FN Thomson Reuters Web of Science™ VR 1.0 PT S AU Riddell, WT Piascik, RS AF Riddell, WT Piascik, RS BE Panontin, TL Sheppard, SD TI Stress ratio effects on crack opening loads and crack growth rates in aluminum alloy 2024 SO FATIGUE AND FRACTURE MECHANICS: TWENTY-NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 29th National Symposium on Fatigue and Fracture Mechanics CY JUN 24-26, 1997 CL STANFORD, CA SP ASTM Comm E8 Fatigue & Fracture DE aluminum alloy 2024; fatigue crack growth; stress ratio; crack closure; mean stress; compliance ID FATIGUE THRESHOLD; CLOSURE BEHAVIOR; MEAN STRESS; PROPAGATION; STEEL AB The effects of stress ratio (R) and crack-opening behavior on fatigue crack growth rates (da/dN) for Aluminum Alloy (AA) 2024-T3 were investigated using conant-Delta K testing, closure measurements, and fractography. Fatigue crack growth rates were obtained for a range of Delta K and stress ratios. Results show that constant Delta K fatigue crack growth for R ranging from near 0 to near 1 is divided into three regions. In legion I, at low R, da/dN increases with increasing R. In Region II, at intermediate R, fatigue crack growth rates are relatively independent of R. In Region III, at high R, further increases in da/dN are observed with increasing R. Near-crack-tip surface closure measurements, using a new noncontact displacement method, show that Region I transient crack growth rates are a result of crack closure. Increasing fatigue surface microvoid density, coinciding with increasing da/dN for Region III fatigue crack growth, suggests that a K-max -dependent damage mechanism is responsible for the transient fatigue crack growth rates characteristic of Region III. For AA 2024-T3, the onset of Region III correlates with a critical value of K-max (13 MPa m(1/2)). Region II fatigue crack growth is unaffected by both closure and K-max effects. In this intrinsic region, Delta K = Delta K-eff. Rates from this region are used to test the validity of closure measurements for Region I fatigue crack growth. Poor correlation of da/dN and Delta K-eff occurs when Delta K-eff are calculated from the fully open load obtained by the reduced strain technique. Good correlation of da/dN and Delta K-eff are found when Delta K-eff, is calculated from local opening loads approximately 0.1 mm behind the crack-tip. C1 NASA, Langley Res Ctr, Natl Res Council, Hampton, VA 23681 USA. RP Riddell, WT (reprint author), NASA, Langley Res Ctr, Natl Res Council, MS 188E, Hampton, VA 23681 USA. NR 40 TC 4 Z9 4 U1 0 U2 7 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2486-4 J9 AM SOC TEST MATER PY 1999 VL 1332 BP 407 EP 425 DI 10.1520/STP14961S PG 19 WC Engineering, Mechanical; Mechanics; Metallurgy & Metallurgical Engineering SC Engineering; Mechanics; Metallurgy & Metallurgical Engineering GA BM73J UT WOS:000079623500022 ER PT S AU Dawicke, DS Newman, JC AF Dawicke, DS Newman, JC BE Panontin, TL Sheppard, SD TI Residual strength predictions for multiple site damage cracking using a three-dimensional finite element analysis and a CTOA criterion SO FATIGUE AND FRACTURE MECHANICS: TWENTY-NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 29th National Symposium on Fatigue and Fracture Mechanics CY JUN 24-26, 1997 CL STANFORD, CA SP ASTM Comm E8 Fatigue & Fracture DE fracture; CTOA; 2024-T3; multiple site damage; stable crack growth AB Fracture tests were conducted on 2.3 mm thick 2024-T3 aluminum alloy middle crack tension, M(T), compact tension, C(T), and multiple-site damage (MSD) specimens covering a wide range in specimen widths (30 to 610 mm). Three-dimensional, elastic-plastic finite element analyses were conducted for each experiment. A critical CTOA value of 5.25 degrees was determined from a 152.4 mm wide C(T) fracture test and was then used to predict the fracture behavior of the other tests. The critical angle was within the scatter in the experimental surface CTOA measurements. All of the predicted failure stresses for the single crack specimens, except for the smallest C(T) and M(T) specimens, were within 5% of the experimental failure stresses. The CTOA criterion predicted stable tearing, link-up stresses, and maximum stresses to within 7% of the experimental measurements. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Dawicke, DS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 20 TC 12 Z9 12 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 0-8031-2486-4 J9 AM SOC TEST MATER PY 1999 VL 1332 BP 815 EP 829 DI 10.1520/STP14985S PG 15 WC Engineering, Mechanical; Mechanics; Metallurgy & Metallurgical Engineering SC Engineering; Mechanics; Metallurgy & Metallurgical Engineering GA BM73J UT WOS:000079623500046 ER PT S AU Nishioka, OS Panontin, TL AF Nishioka, OS Panontin, TL BE Panontin, TL Sheppard, SD TI Ductile crack growth from simulated defects in strength overmatched butt welds SO FATIGUE AND FRACTURE MECHANICS: TWENTY-NINTH VOLUME SE American Society for Testing and Materials Special Technical Publications LA English DT Proceedings Paper CT 29th National Symposium on Fatigue and Fracture Mechanics CY JUN 24-26, 1997 CL STANFORD, CA SP ASTM Comm E8 Fatigue & Fracture DE ductile fracture; micromechanics; void growth and coalescence; Gurson-Tvergaard; weld; defect; J-integral ID NUCLEATION; FRACTURE; FAILURE AB Defects that develop in welds during the fabrication process are frequently manifested as embedded flaws from lack of fusion or lack of penetration. Fracture analyses of welded structures must be able to assess the effect of such defects on the structural integrity of weldments; however, the transferability of R-curves measured in laboratory specimens to defective structural welds has not been fully examined. In the current study, the fracture behavior of an overmatched butt weld containing a simulated buried, lack-of-penetration defect is studied. A specimen designed to simulate pressure vessel butt welds is considered; namely, a center crack panel specimen, of 1.25 inch by 1.25 inch cross section, loaded in tension. The stress-relieved double-V weld has a yield strength 50% higher than that of the plate material, and displays upper shelf fracture behavior at room temperature, Specimens are precracked or notched, loaded monotonically while load-CMOD measurements are made, then stopped and heat tinted to mark the extent of ductile crack growth. These measurements are compared to predictions made using finite element analysis of the specimens using the fracture mechanics code Warp3D, which models void growth using the Gurson-Tvergaard dilitant plasticity formulation within fixed sized computational cells ahead of the crack front, Calibration data for the finite element analyses, namely cell size and initial material porosities, are obtained by matching computational predictions to experimental results from tests of welded compact tension specimens. The calibrated methodology is then used to predict ductile crack growth in defective welds in a structural crack geometry. The R-curves measured in compact tension specimens are compared to those obtained in multi-specimen weld tests, and conclusions as to the transferability of R-curves are discussed. C1 NASA, Mat & Failure Anal Grp, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Nishioka, OS (reprint author), NASA, Mat & Failure Anal Grp, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 18 TC 0 Z9 0 U1 0 U2 1 PU AMER SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 0066-0558 BN 0-8031-2486-4 J9 AM SOC TEST MATER PY 1999 VL 1332 BP 862 EP 883 DI 10.1520/STP14988S PG 22 WC Engineering, Mechanical; Mechanics; Metallurgy & Metallurgical Engineering SC Engineering; Mechanics; Metallurgy & Metallurgical Engineering GA BM73J UT WOS:000079623500049 ER PT B AU Brewer, DA LaBel, KA Ritter, JC Barth, JL Clifton, KS Pearson, SD Peden, J Campbell, A Liang, R AF Brewer, DA LaBel, KA Ritter, JC Barth, JL Clifton, KS Pearson, SD Peden, J Campbell, A Liang, R BE Sharp, R Dressendorfer, P TI The Orbiting Technology Testbed (OTTI) space experiments SO FIFTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 5th European Conference on Radiation and Its Effects on Components and Systems (RADECS 99) CY SEP 13-17, 1999 CL FONTEVRAUD, FRANCE SP Commissariat Energie Atom, IEEE Nucl & Plasma Sci Soc, COGEMA, CNES, TEMIC, CEA DAM, CEA DTA ID SINGLE EVENT UPSET AB Future science, operational, and commercial objectives in space can only be accomplished within cost and schedule constraints by rapidly developing and infusing new technology into missions, improving the capability to reliably predict performance in the space environment, and reducing operational costs. A trade study was performed to determine the optimum combination of space and ground developments and validations needed to accomplish these goals. A concept for a program, the Orbiting Technology Testbed Initiative (OTTI), was defined to address these goals. Results of the trade study and the resultant OTTI concept are described below. C1 NASA, Washington, DC 20546 USA. RP Brewer, DA (reprint author), NASA, Headquarters, Washington, DC 20546 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5726-4 PY 1999 BP 11 EP 17 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Fluids & Plasmas; Physics, Particles & Fields SC Engineering; Instruments & Instrumentation; Physics GA BQ97X UT WOS:000165216900003 ER PT B AU Barak, J AF Barak, J BE Sharp, R Dressendorfer, P TI Empirical modeling of proton induced SEU rates SO FIFTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 5th European Conference on Radiation and Its Effects on Components and Systems (RADECS 99) CY SEP 13-17, 1999 CL FONTEVRAUD, FRANCE SP Commissariat Energie Atom, IEEE Nucl & Plasma Sci Soc, COGEMA, CNES, TEMIC, CEA DAM, CEA DTA ID UPSET AB A new method for calculating proton induced SEU (p-SEU) rates in orbit from heavy ion cross section data is presented. It is based on a simple expression to derive the p-SEU cross section from the heavy ion results which leads to an 'effective LET flux' for the protons in the given orbit. The resulted p-SEU rates are in good agreement with those calculated from measured p-SEU cross section data. A comparison with other empirical models is given. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barak, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5726-4 PY 1999 BP 167 EP 172 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Fluids & Plasmas; Physics, Particles & Fields SC Engineering; Instruments & Instrumentation; Physics GA BQ97X UT WOS:000165216900031 ER PT B AU Reed, RA Marshall, PW Carts, MA Henegar, GL Katz, RB AF Reed, RA Marshall, PW Carts, MA Henegar, GL Katz, RB BE Sharp, R Dressendorfer, P TI Proton-induced single event upset characterization of a 1 Giga-sample per second analog to digital converter SO FIFTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 5th European Conference on Radiation and Its Effects on Components and Systems (RADECS 99) CY SEP 13-17, 1999 CL FONTEVRAUD, FRANCE SP Commissariat Energie Atom, IEEE Nucl & Plasma Sci Soc, COGEMA, CNES, TEMIC, CEA DAM, CEA DTA AB Some high-speed space-borne data acquisition and dissemination systems require conversion of an analog data signal into a digital signal for on-board digital processing. The NASA Geoscience Laser Altimeter System (GLAS) is one such instrument. It uses the Signal Processing Technologies SPT7760 to convert an analog signal from the laser altimeter. The analog data is converted by the SPT7760 at 1 Giga-sample per second (Gsps). These types of data handling applications can typically withstand a relatively high bit error ratio (BER). In this paper, we describe the a novel approach for proton-induced single event upset characterization of the SPT7760. Data is given for operating sample rates from 125 Msps to 1 Gsps. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reed, RA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5726-4 PY 1999 BP 188 EP 192 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Fluids & Plasmas; Physics, Particles & Fields SC Engineering; Instruments & Instrumentation; Physics GA BQ97X UT WOS:000165216900034 ER PT B AU Johnston, AH Rax, BG AF Johnston, AH Rax, BG BE Sharp, R Dressendorfer, P TI Proton damage in linear and digital optocouplers SO FIFTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 5th European Conference on Radiation and Its Effects on Components and Systems (RADECS 99) CY SEP 13-17, 1999 CL FONTEVRAUD, FRANCE SP Commissariat Energie Atom, IEEE Nucl & Plasma Sci Soc, COGEMA, CNES, TEMIC, CEA DAM, CEA DTA ID GAAS AB Fundamental differences in design influence the way that linear and digital optocouplers are degraded by radiation. Linear optocouplers are more affected by current drive conditions because the detector operates in a high-injection region when the LED produces normal light output, and do not have the extra operating margin that is inherent in digital optocouplers. Although LED degradation is often the dominant degradation mechanism in space environments, degradation of optocouplers with improved LEDs is limited by photoresponse degradation. Phototransistor gain has a relatively minor effect except at very high radiation levels. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnston, AH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5726-4 PY 1999 BP 437 EP 443 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Fluids & Plasmas; Physics, Particles & Fields SC Engineering; Instruments & Instrumentation; Physics GA BQ97X UT WOS:000165216900076 ER PT B AU LaBel, KA Marshall, PW Gruner, TD Reed, RA Settles, B Wilmot, J Dougherty, LF Russo, A Foster, MG Yuknis, W Garrison-Darrin, A AF LaBel, KA Marshall, PW Gruner, TD Reed, RA Settles, B Wilmot, J Dougherty, LF Russo, A Foster, MG Yuknis, W Garrison-Darrin, A BE Sharp, R Dressendorfer, P TI Radiation evaluation method of commercial off-the-shelf (COTS) electronic printed circuit boards (PCBs) SO FIFTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 5th European Conference on Radiation and Its Effects on Components and Systems (RADECS 99) CY SEP 13-17, 1999 CL FONTEVRAUD, FRANCE SP Commissariat Energie Atom, IEEE Nucl & Plasma Sci Soc, COGEMA, CNES, TEMIC, CEA DAM, CEA DTA ID ISSUES AB We present a radiation evaluation methodology and proton ground test results for candidate COTS PCBs and their associated electronics for low-altitude, low-inclination orbits. We will also discuss the implications associated with mission orbit and duration. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP LaBel, KA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Darrin, Margaret/H-4305-2011 NR 6 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5726-4 PY 1999 BP 528 EP 534 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Fluids & Plasmas; Physics, Particles & Fields SC Engineering; Instruments & Instrumentation; Physics GA BQ97X UT WOS:000165216900092 ER PT B AU Barak, J Barth, JL Seidleck, CM Marshall, CJ Marshall, PW Carts, MA Reed, RA AF Barak, J Barth, JL Seidleck, CM Marshall, CJ Marshall, PW Carts, MA Reed, RA BE Sharp, R Dressendorfer, P TI Single event upsets in the dual-port-board SRAMs of the MPTB experiment SO FIFTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 5th European Conference on Radiation and Its Effects on Components and Systems (RADECS 99) CY SEP 13-17, 1999 CL FONTEVRAUD, FRANCE SP Commissariat Energie Atom, IEEE Nucl & Plasma Sci Soc, COGEMA, CNES, TEMIC, CEA DAM, CEA DTA ID SEU AB The in-flight data of SEUs in the devices of panels B and C of the MPTB experiments are presented. Ground test data for M65656 are used to calculate the SEU rates in this device using the calculated flux of ions along the orbit. The models used are CREME96, simple expressions derived here, and the figure of merit model. A very good agreement is found between these calculations and the observed rates. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barak, J (reprint author), NASA, Goddard Space Flight Ctr, Code 562-1, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5726-4 PY 1999 BP 582 EP 587 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Fluids & Plasmas; Physics, Particles & Fields SC Engineering; Instruments & Instrumentation; Physics GA BQ97X UT WOS:000165216900101 ER PT J AU Brodziak, J Hendrickson, L AF Brodziak, J Hendrickson, L TI An analysis of environmental effects on survey catches of squids Loligo pealei and Illex illecebrosus in the northwest Atlantic SO FISHERY BULLETIN LA English DT Article ID LONG-FINNED SQUID; GROWTH AB An analysis of environmental effects on autumn survey catches of two commercially exploited squid species, Loligo pealei and Illex illecebrosus, was conducted. Research survey data collected during 1967-94 were used to determine the significance and relative importance of average depth of tow, time of day, bottom temperature, and surface temperature on bottom trawl catches of L. pealei, a neritic species, and I. illecebrosus, an oceanic species. We examined habitat associations of both species by using randomization methods and found that L. pealei was consistently associated with all of the environmental factors examined. In comparison with L. pealei, catches of I. illecebrosus were much lower and associations with environmental factors were inconsistent. We also examined whether environmental conditions affected catches of juvenile and adult squid differentially. Depth had an important effect on the magnitude of juvenile and adult L. pealei catches, with the ratio of juvenile to adult catches decreasing with depth. Depth had a similar, but less pronounced, effect on I. illecebrosus catches. Time of day also affected L. pealei and I. illecebrosus catches. Catches of both species were lowest at night and diel effects were more pronounced for juveniles than for adults. Bottom and surface temperatures had a substantial effect on catches of juvenile and adult L. pealei but had a variable influence on I. illecebrosus catches. The joint effects of depth stratification, time of day, and annual squid abundance on survey catches were also analyzed to determine correction factors for diel differences in catchability of juvenile and adult squid. Significant diel differences in catchability were detected for juvenile and adult L. pealei and for juvenile I. illecebrosus and diel correction factors were determined for survey catches of these size categories. In contrast, significant diel differences in catchability of adult I. illecebrosus were not detected. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Newport, OR 97365 USA. NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Brodziak, J (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2030 S Marine Sci Dr, Newport, OR 97365 USA. NR 39 TC 32 Z9 36 U1 2 U2 3 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 1999 VL 97 IS 1 BP 9 EP 24 PG 16 WC Fisheries SC Fisheries GA 155WN UT WOS:000077969500002 ER PT J AU Polovina, JJ Kleiber, P Kobayashi, DR AF Polovina, JJ Kleiber, P Kobayashi, DR TI Application of TOPEX-POSEIDON satellite altimetry to simulate transport dynamics of larvae of spiny lobster, Panulirus marginatus in the Northwestern Hawaiian Islands, 1993-1996 SO FISHERY BULLETIN LA English DT Article ID GENETIC-VARIATION; SEA-LEVEL; RECRUITMENT; ARCHIPELAGO; HEIGHTS AB A commercially valuable trap fishery for spiny lobster (Panulirus marginatus) has existed in the Northwestern Hawaiian Islands since the late 1970s. Fisheries landings and research trapping show that spawning biomass and recruitment to the fishery collapsed in 1990 in the northern portion of the fishing ground and that there has been no recovery to the present, although recruitment remained strong at banks 670 km to the southeast. An advection-diffusion model is used to investigate larval transport dynamics between these two regions. The movement model is driven by geostrophic currents computed every 10 days from sea surface height obtained from TOPEX-POSEIDON satellite altimetry. The larval transport simulations indicate that even though larvae have a pelagic period of 12 months. banks differ substantially in the proportion of larvae they retain from resident spawners as well as the proportion of larvae they receive from other banks. In particular, recruitment to the northern portion of the fishing grounds is weak due to a very low local spawning biomass and a very limited contribution of larvae from the area of strong recruitment and high spawning biomass in the southeast. The results also suggest that satellite altimetry can provide useful information on physical dynamics for recruitment studies. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Polovina, JJ (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, 2570 Dole St, Honolulu, HI 96822 USA. NR 14 TC 57 Z9 64 U1 0 U2 3 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 1999 VL 97 IS 1 BP 132 EP 143 PG 12 WC Fisheries SC Fisheries GA 155WN UT WOS:000077969500013 ER PT S AU Yu, W AF Yu, W BE Gnade, B Kelley, EF TI Surface plasmon tunable filter and flat panel display device SO FLAT PANEL DISPLAY TECHNOLOGY AND DISPLAY METROLOGY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Flat Panel Display Technology and Display Metrology CY JAN 27-29, 1999 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, SPIE DE surface plasmon; tunable filter; flat panel display; LCD AB Surface plasmon tunable filter (SPTF) is a new technology underdevelopment at Jet Propulsion Lab. I had discussed the theoretical model and possible applications of using surface plasmon tunable filters for flat panel display device in several SPIE meetings. Now a prototype of surface plasmon tunable filter has been fabricated at JPL, and the experiment measurement will be discussed in this paper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yu, W (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 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 0-8194-3107-9 J9 P SOC PHOTO-OPT INS PY 1999 VL 3636 BP 69 EP 72 PG 4 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Optics SC Materials Science; Optics GA BN06L UT WOS:000080536100008 ER PT S AU Munoz, C Rushby, J AF Munoz, C Rushby, J BE Wing, JM Woodcock, J Davies, J TI Structural embeddings: Mechanization with method SO FM'99-FORMAL METHODS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 1st World Congress on Formal Methods in the Development of Computing Systems (FM 99) CY SEP 20-24, 1999 CL TOULOUSE, FRANCE SP AMAST, Aerospatiale Airbus, Alcatel Space, CCIT, CEPIS, CNES, CNRS, Cap Gemimi, Carnegie Mellon Univ, Conseil Reg Midi Pyrenees, DGA, EATCS, ESA, ETAPS, European Union, FACS, FME, France Telecom, IFIP, INRIA, IPSJ, IRIT, JSSST, LAAS, Mairie Toulouse, Matra Marconi Space, ONERA, Tech Univ Delft, Tech Univ Denmark, Tech Univ Graz, Translimina, Univ Oxford, Univ Reading ID PVS; REQUIREMENTS; VERIFICATION; SYSTEMS; LOGIC AB The most powerful tools for analysis of formal specifications are general-purpose theorem provers and model checkers, but these tools provide scant methodological support. Conversely, those approaches that do provide 8 cell-developed method generally have less powerful automation. It is natural, therefore, to try to combine the better-developed methods with the more powerful general-purpose tools. An obstacle is that the methods and the tools often employ very different logics. We argue that methods are separable From their logics and are largely concerned with the structure and organization of specifications. We propose a technique called structural embedding that allows the structural elements of a method to be supported by a general-purpose tool, while substituting the logic of the tool for that of the method. We have found this technique quite effective and we provide some examples of its application. We also suggest how general-purpose systems could be restructured to support this activity better. C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. SRI Int, Comp Sci Lab, Menlo Park, CA 94025 USA. RP Munoz, C (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Mail Stop 132C,3 W Reid St, Hampton, VA 23681 USA. NR 42 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66587-0 J9 LECT NOTES COMPUT SC PY 1999 VL 1708 BP 452 EP 471 PG 20 WC Computer Science, Theory & Methods SC Computer Science GA BP83L UT WOS:000086370500026 ER PT S AU Chiar, JE Pendleton, YJ AF Chiar, JE Pendleton, YJ BE Greenberg, JM Li, A TI The nature and evolution of interstellar organics SO FORMATION AND EVOLUTION OF SOLIDS IN SPACE SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Study Institute on Formation and Evolution of Solids in Space CY MAR 10-21, 1997 CL ETTORE MAJORANA CTR SCI CULTURE, ERICE, ITALY SP NATO, Sci Affairs Div HO ETTORE MAJORANA CTR SCI CULTURE ID TIME-DEPENDENT CHEMISTRY; OPHIUCHI MOLECULAR CLOUD; INFRARED-EMISSION BANDS; TAURUS DARK CLOUDS; GALACTIC-CENTER; GRAIN MANTLES; ABSORPTION FEATURES; ICE ANALOGS; MU-M; MICRON SPECTRA AB Infrared spectroscopy of solid state absorption features in dense and diffuse interstellar clouds has greatly advanced our understanding of the composition of dust in these regions. However, serious questions regarding the evolution of dust grains have now developed as a result of recent compositional discoveries. The creation of complex organic refractory material on or in icy mantles of grains residing in the protected environs of dense molecular clouds is thought to be the pathway by which organic carriers are formed. Two absorption features in particular, one near 3.4 mu m and another clear 4.62 mu m have been attributed to an organic refractory residue which can be produced by ultraviolet photolysis of interstellar ices. However, even though the production site for both features is expected to occur within dense molecular clouds, these features are observed in very different physical regimes of the interstellar medium (ISM). The 3.4 mu m feature is observed in the low density, low temperature portion of the diffuse ISM, and the 4.62 mu m feature is observed towards embedded protostars in high density molecular clouds. Dust grains are thought to cycle between the dense and diffuse clouds fairly efficiently and on rather short timescales, thus the noteworthy absence of the diffuse ISM 3.4 mu m hydrocarbon absorption Band and the unique presence of the 4.62 mu m band in the spectra of dense molecular cloud objects presents difficulties for the production site and/or the cycling efficiency. In this paper, we focus on comparisons between the dense and diffuse clouds which specifically address the nature and evolution of the organic component of interstellar dust. A greater understanding of the origin and distribution of interstellar organics is essential in any evaluation of the organic inventory available for incorporation into planetary systems and the precursor planetesimal stage. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chiar, JE (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 84 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-5474-5 J9 NATO ADV SCI I C-MAT PY 1999 VL 523 BP 29 EP 52 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM63C UT WOS:000079308500003 ER PT S AU Charnley, SB AF Charnley, SB BE Greenberg, JM Li, A TI The organic chemistry of TMC-1 revisited SO FORMATION AND EVOLUTION OF SOLIDS IN SPACE SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Study Institute on Formation and Evolution of Solids in Space CY MAR 10-21, 1997 CL ETTORE MAJORANA CTR SCI CULTURE, ERICE, ITALY SP NATO, Sci Affairs Div HO ETTORE MAJORANA CTR SCI CULTURE ID METHANOL; CLOUDS; MOLECULES; TAURUS AB I reconsider the formation of complex interstellar molecules in the dark cloud TMC-1. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Charnley, SB (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. EM charnley@dusty.arc.nasa.gov RI Charnley, Steven/C-9538-2012 NR 22 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-5474-5 J9 NATO ADV SCI I C-MAT PY 1999 VL 523 BP 131 EP 137 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM63C UT WOS:000079308500009 ER PT S AU Tielens, AGGM AF Tielens, AGGM BE Greenberg, JM Li, A TI The destruction of interstellar dust SO FORMATION AND EVOLUTION OF SOLIDS IN SPACE SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Study Institute on Formation and Evolution of Solids in Space CY MAR 10-21, 1997 CL ETTORE MAJORANA CTR SCI CULTURE, ERICE, ITALY SP NATO, Sci Affairs Div HO ETTORE MAJORANA CTR SCI CULTURE ID GRAIN DESTRUCTION; CHEMICAL EVOLUTION; SOLAR NEIGHBORHOOD; STELLAR WINDS; MASS-LOSS; SHOCKS; STARS; PHYSICS; ENERGY; SPACE AB This paper reviews the detailed physics of the processes involved in the destruction of interstellar dust in interstellar shocks: sputtering by impacting gas atoms, and vaporization and shattering by grain-grain collisions. An analytical formalism is developed that describes these processes. The structure of interstellar shocks is discussed and the fate of grains in the cooling postshock gas is followed. Theoretical calculations show that high velocity shocks (v > 50 km/s) destroy interstellar dust efficiently. A simple stick model for evolution of interstellar dust in the interstellar medium (ISM), which includes dust destruction by shocks in the Warm ISM, accretion in the cloud phases, stardust injection, and mixing between the interstellar cloud and intercloud phases is described. It is concluded that fast shocks occur so frequently that the lifetime of refractory grains such as graphite and silicates is only 5 x 10(8) yr, much shorter than the stardust injection timescale. Consequently, growth of interstellar dust through accretion in the cloud phases of the ISM has to be rapid as well. This model is also used to derive rather directly dust lifetimes against destruction and accretion timescales from observations of depletions in the cloud and intercloud phases of the ISM. These are compared to the theoretically calculated lifetimes and the implications are discussed. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Tielens, AGGM (reprint author), NASA, Ames Res Ctr, MS245-3, Moffett Field, CA 94035 USA. NR 86 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-5474-5 J9 NATO ADV SCI I C-MAT PY 1999 VL 523 BP 331 EP 375 PG 45 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM63C UT WOS:000079308500024 ER PT S AU Duong, TA Daud, T AF Duong, TA Daud, T BE Mira, J SanchezAndres, JV TI Cascade Error Projection: A learning algorithm for hardware implementation SO FOUNDATIONS AND TOOLS FOR NEURAL MODELING, PROCEEDINGS, VOL I SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 5th International Work-Conference on Artificial and Natural Neural Networks (IWANN 99) CY JUN 02-04, 1999 CL ALICANTE, SPAIN SP Asociac Espanola Redes Neuronales, Univ Nacl Educ Distancia, Univ Miguel Hernandez, IFIP, Spanish RIG IEEE Neural Networks Council AB In this paper, we workout a detailed mathematical analysis for a new learning algorithm termed Cascade Error Projection (CEP) and a general learning framework. This frame work can be used to obtain the cascade correlation learning algorithm by choosing a particular set of parameters. Furthermore, CEP learning algorithm is operated only on one layer, whereas the other set of weights can he calculated deterministically. In association with the dynamical stepsize change concept to convert the weight update from infinite space into a finite space, the, relation between the current stepsize and the previous energy level is also given and the estimation procedure for optimal stepsize is used for validation of our proposed technique. The weight values of zero are used for starting the learning for every layer, and a single hidden unit is applied instead of using a pool of candidate hidden units similar to cascade correlation scheme. Therefore, simplicity in hardware implementation is also obtained. Furthermore, this analysis allows us to select from other methods (such as the conjugate gradient descent or the Newton's second order) one of which will be a good candidate for the learning technique. The choice of learning technique depends on the constraints of the problem (e.g, speed, performance. and hardware implementation); one technique may be more suitable than others. Moreover, for a discrete weight space. the theoretical analysis presents the capability of learning with limited weight quantization. Finally, 5- to 8-bit parity and chaotic time series prediction problems are investigated; the simulation results demonstrate that 4-bit or more weight quantization is sufficient for learning neural network using CEP. In addition, it is demonstrated that this technique is able to compensate for less bit weight resolution by incoporating additional hidden units However, generation result may suffer somewhat with lower bit weight quantization. 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 12 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 3-540-66069-0 J9 LECT NOTES COMPUT SC PY 1999 VL 1606 BP 450 EP 457 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA BQ95X UT WOS:000165140200048 ER PT S AU Jeganathan, M Portillo, A Racho, C Lee, S Erickson, D DePew, J Monacos, S Biswas, A AF Jeganathan, M Portillo, A Racho, C Lee, S Erickson, D DePew, J Monacos, S Biswas, A BE Mecherle, GS TI Lessons learnt from the Optical Communications Demonstrator (OCD) SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE DE optical communications; laser communications; beacon acquisition; tracking; free-space; LEO; GEO; OCD ID DESIGN AB The Optical Communications Demonstrator (OCD) is a laboratory based lasercom terminal that was developed to validate several key technologies such as precision beam pointing, high bandwidth beacon tracking and beacon acquisition. The unique architecture of OCD uses a single focal plane array (FPA) and a single fine steering mirror (FSM) for beacon acquisition, beacon tracking and point-ahead compensation. A fiber-coupled laser transmitter further reduces the complexity of the terminal. Over the last year, system level integration, test and characterization of the terminal were conducted. Here we present results from the integration and test (I&T) of the terminal with the Lasercom Terminal Evaluation Station (LTES), with particular emphasis on the fine tracking performance. Furthermore, we will describe lessons learnt from the implementation and testing of OCD that are relevant to the design of future flight optical communication terminals. The completed OCD is now being used in a series of ground-ground experiments to understand atmospheric effects and to gain experience operating the OCD. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jeganathan, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 161-135, Pasadena, CA 91109 USA. NR 15 TC 15 Z9 15 U1 2 U2 7 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 23 EP 30 DI 10.1117/12.346188 PG 8 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500003 ER PT S AU Biswas, A Ceniceros, J Novak, M Jeganathan, M Portillo, A Erickson, D Depew, J Sanii, B Lesh, JR AF Biswas, A Ceniceros, J Novak, M Jeganathan, M Portillo, A Erickson, D Depew, J Sanii, B Lesh, JR BE Mecherle, GS TI 45 Km horizontal path optical link experiment SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE DE free-space optical communications; atmospheric scintillation; lasercom; terrestrial optical link ID SCINTILLATION; SPACE AB Mountain-top to mountain-top optical link experiments have been initiated at JPL, in order to perform a systems level evaluation of optical communications. Progress made so far is reported. The NASA, JPL developed optical communications demonstrator (OCD) is used to transmit a laser signal from Strawberry Peak (SP), located in the San Bernadino mountains of California. This laser beam is received by a 0.6 m aperture telescope at JPL's Table Mountain Facility (TMF), located in Wrightwood, California. The optical link is bi-directional with the TMF telescope transmitting a continuous 4-wave (cw) 780 nm beacon and the OCD sending back a 840 nm, 100-500 Mbps pseudo noise (PN) modulated, laser beam. The optical link path is at an average altitude of 2 Km above sea level, covers a range of 46.8 Km and provides an atmospheric channel equivalent to similar to 4 air masses. Average received power measured at either end fall well within the uncertainties predicted by link analysis. The reduction in normalized intensity variance (sigma(I)(2)) for the 4-beam beacon, compared to each individual beam, at SP, was from similar to 0.68 to 0.22. With some allowance for intra-beam mis-alignment, this is consistent with incoherent averaging. The sigma(I)(2) measured at TMF similar to 0.43 +/-0.22 exceeded the expected aperture averaged value of < 0.1, probably because of beam wander. The focused spot sizes of similar to 162 +/- 6 mu m at the TMF Coude and similar to 64 +/- 3 mu m on the OCD compare to the predicted size range of 52-172 mu m and 57-93 mu m, respectively. This is consistent with 4-5 arcsec of atmospheric "seeing". The preliminary evaluation of OCD's fine tracking indicates that the uncompensated tracking error is similar to 3.3 mu rad compared to similar to 1.7 mu rad observed in the laboratory. Fine tracking performance was intermittent, primarily due to beacon fades on the OCD tracking sensor. The best bit error rates observed while tracking worked were 1E-5 to 1E-6. C1 CALTECH, Jet Prop Lab, Opt Commun Grp, Pasadena, CA 91109 USA. RP Biswas, A (reprint author), CALTECH, Jet Prop Lab, Opt Commun Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 4 Z9 4 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 43 EP 53 DI 10.1117/12.346202 PG 11 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500005 ER PT S AU Chen, C Alexander, JW Hemmati, H Monacos, S Yan, T Lee, S Lesh, JR Zingales, S AF Chen, C Alexander, JW Hemmati, H Monacos, S Yan, T Lee, S Lesh, JR Zingales, S BE Mecherle, GS TI System requirements for a deep space optical transceiver SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE AB The functional requirements and design drivers for an Optical Communications subsystem are assessed based on the system requirements imposed by a proposed Europa Orbiter mission. Unlike near-Earth optical communications systems, deep space missions impose a unique set of requirements that drives the subsystem design. Significant challenges on laser efficiency, thermal control, pointing and tracking, stray/scatter light control, and subsystem mass/power need to be addressed for a successful subsystem implementation. The baseline design concept for a lasercom subsystem for the Europa orbiter mission employs a 30-cm diameter, diffraction-limited telescope, and a diode pumped solid state laser operating at 1.06 mu m to support downlink communications. The baseline pointing and tracking approach is to perform Earth Image tracking with occasional calibration using the Earth-moon or Earth-star images. At high phase angles when the Earth image does not provide sufficient brightness for high rate tracking, inertial sensors (accelerometers) measurements are used to propagate the knowledge of the optical boresight at a higher rate in between celestial reference updates. Additionally, uplink beacon tracking will be used to support pointing at short range and near solar opposition when Earth image along does not provide sufficient signal power for tracking. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chen, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 12 Z9 12 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 142 EP 152 DI 10.1117/12.346174 PG 11 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500014 ER PT S AU Yan, TY Chen, CC AF Yan, TY Chen, CC BE Mecherle, GS TI Design and development of a baseline deep space optical PPM transceiver SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE AB One of the NASA technology development program at the Jet Propulsion Laboratory aims to increase the information return capability while reducing the size of the spacecraft via laser communications. The deep space optical transceiver developed under this program employs pulse position modulation (PPM) for both uplink and downlink transmissions. An integral part of the transceiver is the development of signal acquisition and tracking subsystem. This paper describes the baseline design of the electronic assembly within the transceiver and modifications that are necessary for deep space communications. A two phase breadboard activity will be described to reduce technological risks associated with the development. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yan, TY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 154 EP 164 DI 10.1117/12.346175 PG 11 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500015 ER PT S AU Biswas, A Hemmati, H Lesh, JR AF Biswas, A Hemmati, H Lesh, JR BE Mecherle, GS TI High data-rate laser transmitters for free-space laser communications SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE ID AMPLIFIERS; RADIATION AB Master-oscillator power-amplifier (MOPA) laser systems, for future lasercom terminals to be flown in space are being developed and characterized. These lasers fall into groups for applications in deep space and near earth (including GEO) orbiting satellites. For deep space applications a diode pumped Q-switched Nd:YVO4 oscillator and a multi-pass Nd:YAG amplifier laser with an average output power of 1.5 W and capable of supporting repetition rates of 100 KHz was studied. This laser emits at 1064 nm and was tested with pulse position modulation at data rates of 400 Kbps. The laser pulse width (similar to 2 ns FWHM) and timing jitter (+/- 8 ns) are reported with relevant discussions pertaining to deep space performance. For near earth applications, a two stage diode pumped fiber amplifier system providing 1072 nm emission with 4 W of average power and capable of supporting data rates of 2.5 Gbps is briefly described. A second semiconductor flared amplifier system emitting at 980 nm has also been developed and is awaiting characterization. C1 CALTECH, Jet Prop Lab, Opt Commun Grp, Pasadena, CA 91106 USA. RP Biswas, A (reprint author), CALTECH, Jet Prop Lab, Opt Commun Grp, 4800 Oak Grove Dr, Pasadena, CA 91106 USA. NR 22 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 169 EP 178 PG 10 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500016 ER PT S AU Ortiz, GG Jeganathan, M Sandusky, JV Hemmati, H AF Ortiz, GG Jeganathan, M Sandusky, JV Hemmati, H BE Mecherle, GS TI Design of a 2.5 Gbps optical transmitter for the International Space Station SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE DE optical communications; laser transmitter; high data tate; MOPA; PRBS generator; boresight reference signal ID COMMUNICATIONS DEMONSTRATOR AB A high data rate laser transmitter assembly (LTA) has been designed as the source for an optical free-space communication link between the International Space Station and the 1-meter Optical Communication Telescope Laboratory (OCTL) to be built at the Table Mountain Facility (TMF, Wrightwood, CA). The transmitter design concept uses a fiber-based master oscillator power amplifier (MOPA) configuration with an average output power of 200 mW at a 1550 nm transmit wavelength. This transmitter source is also designed to provide a signal at 980 nm to the silicon-based focal plane array for the point-ahead beam control function. This novel integration of a 980 nm boresight signal allows the use of silicon based imagers for the acquisition/tracking and point-ahead functions, yet permits the transmit signal to be at any wavelength outside the silicon sensitivity. The LTA, a sub-system of the Flight Terminal, has been designed to have a selectable data rate from 155 - 2500 Mbps in discrete steps. It also incorporates a 2.5 Gbps pseudo-random bit sequence (PRBS) generator for complete link testing and diagnostics. The design emphasizes using commercial off the shelf components (COTS). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ortiz, GG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 161-135, Pasadena, CA 91109 USA. NR 8 TC 2 Z9 2 U1 1 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 179 EP 184 DI 10.1117/12.346177 PG 6 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500017 ER PT S AU Sandusky, JV Jeganathan, M Ortiz, G Biswas, A Lee, S Parker, G Liu, B Johnson, D DePew, J Lesh, JR AF Sandusky, JV Jeganathan, M Ortiz, G Biswas, A Lee, S Parker, G Liu, B Johnson, D DePew, J Lesh, JR BE Mecherle, GS TI Overview of the preliminary design of the Optical Communication Demonstration and High-Rate Link Facility SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE DE optical communication; International Space Station; lasercomm AB This paper presents an overview of the preliminary design of both the flight and ground systems of the Optical Communication Demonstration and High-Rate Link Facility which will demonstrate optical communication from the International Space Station to ground after its deployment in October 2002. The overview of the preliminary design of the Flight System proceeds by contrasting it with the design of the laboratory-model unit, emphasizing key changes and the rationale behind the design choices. After presenting the preliminary design of the Ground System, the timetable for the construction and deployment of the flight and ground systems is outlined. C1 CALTECH, Jet Prop Lab, Opt Commun Grp, Pasadena, CA 91109 USA. RP Sandusky, JV (reprint author), CALTECH, Jet Prop Lab, Opt Commun Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 5 Z9 5 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 185 EP 191 DI 10.1117/12.346178 PG 7 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500018 ER PT S AU Ceniceros, JM Lesh, JR AF Ceniceros, JM Lesh, JR BE Mecherle, GS TI Optical communications study for the Next Generation Space Telescope SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE AB The Next Generation Space Telescope (NGST), part of NASA's Origins program, is a follow on to the Hubble Space Telescope expected to provide timely new science along with answering fundamental questions. NGST is a large diameter, infrared optimized telescope with imaging and spectrographic detectors which will be used to help study the origin of galaxies. Due to the large data NGST will collect, Goddard Space Flight Center has considered the use of optical communications for data downlink. The Optical Communications Group at the Jet Propulsion Laboratory has performed a study on optical communications systems for NGST. The objective of the study was to evaluate the benefits gained through the use of optical communication technologies. Studies were performed for each of four proposed NGST orbits. The orbits considered were an elliptical orbit about the semi stable second Lagrangian point, a 1 by 3 AU elliptic orbit around the sun, a 1 AU drift orbit, and a 1 AU drift orbit at a 15 degree incline to the ecliptic plane. An appropriate optical communications system was determined for each orbit. Systems were evaluated in terms of mass, power consumption, size, and cost for each of the four proposed orbits. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ceniceros, JM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 161-135, Pasadena, CA 91109 USA. NR 3 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 192 EP 200 DI 10.1117/12.346180 PG 9 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500019 ER PT S AU Wilson, KE Britcliffe, M Golshan, N AF Wilson, KE Britcliffe, M Golshan, N BE Mecherle, GS TI Progress in design and construction of the optical communications laser laboratory SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE DE free space optical communications; lasercom; telescopes; ground stations; adaptive optics; astrometry; Table Mountain Facility ID EXPERIMENTAL OPERATIONS AB The deployment of advanced hyperspectral imaging and other Earth sensing instruments on board Earth observing satellites is driving the demand for high-data-rate communications. Optical communications meet the required data rates with small, low-mass, and low-power communications packages. JPL, as NASA's lead center in optical communications, plans to construct a 1-m Optical Communications Telescope Laboratory (OCTL) at its Table Mountain Facility (TMF) complex in the San Gabriel Mountains of Southern California. The design of the building has been completed, and the construction contractor has been selected. Ground breaking is expected to start at the beginning of the 1999 TMF construction season. A request for proposal (RFP) has been issued for the procurement of the telescope system. Prior to letting the RFP we conducted a request for information with industry for the telescope system. Several vendors responded favorably and provided information on key elements of the proposed design. These inputs were considered in developing the final requirements in the RFP. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilson, KE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 201 EP 205 DI 10.1117/12.346181 PG 5 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500020 ER PT S AU Hemmati, H Page, NA AF Hemmati, H Page, NA BE Mecherle, GS TI Preliminary opto-mechanical design for the X2000 transceiver SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE DE optical communication; optical design AB Preliminary optical design and mechanical conceptual design for a 30 cm aperture transceiver are described. A common aperture is used for both transmit and receive. Special attention was given to off-axis and scattered light rejection and isolation of the receive channel from the transmit channel. Requirements, details of the design and preliminary performance analysis of the transceiver are provided. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hemmati, H (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 6 Z9 6 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 206 EP 211 DI 10.1117/12.346182 PG 6 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500021 ER PT S AU Tsou, HP Yan, TY AF Tsou, HP Yan, TY BE Mecherle, GS TI Maximum likelihood based extended-source spatial acquisition and tracking for planetary optical communications SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE DE laser-pointing; extended-source image acquisition tracking; maximum likelihood estimation; optical communications AB This paper describes an extended-source spatial acquisition and tracking scheme for planetary optical communications. This scheme uses the Sun-lit Earth image as the beacon signal, which can be computed according to the current Sun-Earth-Probe angle from a pre-stored Earth image or a received snapshot taken by other Earth-orbiting satellite. Onboard the spacecraft, the reference image is correlated in the transform domain with the received image obtained from a detector array, which is assumed to have each of its pixels corrupted by an independent additive white Gaussian noise. The coordinate of the ground station is acquired and tracked, respectively, by an open-loop acquisition algorithm and a closed-loop tracking algorithm derived from the maximum likelihood criterion. As shown in the paper, the optimal spatial acquisition requires solving two nonlinear equations, or iteratively solving their linearized variants, to estimate the coordinate when translation in the relative positions of onboard and ground transceivers is considered. Similar assumption of linearization leads to the closed-loop spatial tracking algorithm in which the loop feedback signals can be derived from the weighted transform-domain correlation. Numerical results using a sample Sun-lit Earth image demonstrate that sub-pixel resolutions can be achieved by this scheme in a high disturbance environment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tsou, HP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 214 EP 221 DI 10.1117/12.346183 PG 8 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500022 ER PT S AU Alexander, JW Lee, S Chen, C AF Alexander, JW Lee, S Chen, C BE Mecherle, GS TI Pointing and tracking concepts for deep space missions SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE AB This paper summarizes part of a FY1998 effort on the design and development of an optical communications (Opcomm) subsystem for the Advanced Deep Space System Development (ADSSD) Project. This study was funded by the JPL X2000 program to develop an optical communications (Opcomm) subsystem for use in future planetary missions. The goal of this development effort was aimed at providing prototype hardware with the capability of performing uplink, downlink, and ranging functions from deep space distances. Such a system was envisioned to support future deep space missions in the Outer Planets/Solar Probe (OPSP) mission set such as the Pluto express and Europa orbiter by providing a significant enhancement of data return capability. A study effort was initiated to develop a flyable engineering model optical terminal to support the proposed Europa Ol biter mission - as either the prime telecom subsystem or for mission augmentation. The design concept was to extend the prototype lasercom terminal development effort currently conducted by JPL's Optical Communications Group. The subsystem would track the sun illuminated Earth at Europa and farther distances for pointing reference. During the course of the study, a number of challenging issues were found. These included thermo-mechanical distortion, straylight control, and pointing. This paper focuses on the pointing aspects required to locate and direct a laser beam from a spacecraft (S/C) near Jupiter to a receiving station on Earth. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Alexander, JW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 14 Z9 14 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 230 EP 249 DI 10.1117/12.346185 PG 20 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500024 ER PT S AU Racho, C Portillo, A AF Racho, C Portillo, A BE Mecherle, GS TI Characterization and design of digital pointing subsytem for optical communication demonstrator SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE AB The Optical Communications Demonstrator (OCD) is a laboratory-based lasercom demonstration terminal designed to validate several key technologies, including beacon acquisition, high bandwidth tracking, precision beam pointing, and point-ahead compensation functions. It has been under active development over the past few years. The instrument uses a CCD array detector for both spatial acquisition and high-bandwidth tracking, and a fiber coupled laser transmitter. The array detector tracking concept provides wide field-of-view acquisition and permits effective platform jitter compensation and point-ahead control using only one steering mirror. This paper describes the detailed design and characterization of the digital control loop system which includes the Fast Steering Mirror (FSM), the CCD image tracker, and the associated electronics. The objective of this work is to improve the overall system performance using laboratory measured data. The design of the digital control loop is based on a linear time invariant open loop model. The closed loop performance is predicted using the theoretical model. With the digital filter programmed into the OCD control software, data is collected to verify the predictions. This paper presents the results of the system modeling and perfomance analysis. It has been shown that measurement data closely matches theoretical predictions. An important part of the laser communication experiment is the ability of FSM: to track the laser beacon within the required tolerances. The pointing must be maintained to an accuracy that is much smaller than the transmit signal beamwidth. For an earth orbit distance, the system must be able to track the receiving station to within a few microradians. The failure to do so will result in a severely degraded system performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Racho, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 6 Z9 6 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 250 EP 261 DI 10.1117/12.346186 PG 12 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500025 ER PT S AU Biswas, A Hemmati, H Lesh, JR AF Biswas, A Hemmati, H Lesh, JR BE Mecherle, GS TI High data-rate laser transmitters for free-space laser communications SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE AB Master-oscillator power-amplifier (MOPA) laser systems, for future lasercom terminals to be flown in space are being developed and characterized. These lasers fall into groups for applications in deep space and near earth (including GEO) orbiting satellites. For deep space applications a diode pumped Q-switched Nd:YVO4 oscillator and a multi-pass Nd:YAG amplifier laser with an average output power of 1.5 W and capable of supporting repetition rates of 100 KHz was studied. This laser emits at 1064 nm and was tested with pulse position modulation at data rates of 400 Kbps. The laser pulse width (similar to 2 ns FWHM) and timing jitter (+/- 8 ns) are reported with relevant discussions pertaining to deep space performance. For near earth applications, a two stage diode pumped fiber amplifier system providing 1072 nm emission with 4 W of average power and capable of supporting data rates of 2.5 Gbps is briefly described. A second semiconductor flared amplifier system emitting at 980 nm has also been developed and is awaiting characterization. C1 CALTECH, Jet Prop Lab, Opt Commun Grp, Pasadena, CA 91106 USA. RP Biswas, A (reprint author), CALTECH, Jet Prop Lab, Opt Commun Grp, 4800 Oak Grove Dr, Pasadena, CA 91106 USA. NR 4 TC 2 Z9 2 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 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 269 EP 277 DI 10.1117/12.346189 PG 9 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500027 ER PT S AU Erickson, DM Tsiang, DH Jeganathan, M AF Erickson, DM Tsiang, DH Jeganathan, M BE Mecherle, GS TI Upgrade of the atmospheric visibility monitoring system SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XI CY JAN 26-27, 1999 CL SAN JOSE, CA SP SPIE DE atmospheric visibility; atmospheric transmission; atmospheric attenuation; cloud-cover statistics; free-space optical communication; laser Communication; AVM AB The Atmospheric Visibility Monitoring (AVM) project gathers data on the transmission of light through the atmosphere. These data are measured and collected at autonomous observatories using stellar photometric techniques. The information gathered is used to build statistical models that assess the quality of future space-to-ground optical communication links. The first of the three currently running AVM observatories became operational in 1994. Jet Propulsion Laboratory (JPL) is upgrading all three observatories. The upgrade includes new Charge Coupled Device (CCD) imagers, Windows NT-based computers and new control software. The new CCDs improve the following: near IR performance, daylight photometry, pixel field-of-view, intensity resolution and signal-to-noise ratios. Employing these new CCDs requires upgrading the CPU, operating system and control software. Together these changes improve the quality of future data obtained and processed by the AVM system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Erickson, DM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3085-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3615 BP 310 EP 315 DI 10.1117/12.346193 PG 6 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BN04H UT WOS:000080481500031 ER PT B AU Barnard, S Biswas, R Saini, S Van der Wijngaart, R Yarrow, M Zechtzer, L Foster, I Larsson, O AF Barnard, S Biswas, R Saini, S Van der Wijngaart, R Yarrow, M Zechtzer, L Foster, I Larsson, O GP IEEE COMP SOC IEEE COMP SOC TI Large-scale distributed computational fluid dynamics on the Information Power Grid using globus SO FRONTIERS '99 - THE SEVENTH SYMPOSIUM ON THE FRONTIERS OF MASSIVELY PARALLEL COMPUTATION, PROCEEDINGS LA English DT Proceedings Paper CT 7th Symposium on the Frontiers of Massively Parallel Computation (Frontiers 99) CY FEB 21-25, 1999 CL ANNAPOLIS, MD SP IEEE Comp Soc Tech Comm Comp Architecture, USRA, CESDIS, NASA Goddard Space Flight Ctr AB This paper describes an experiment in which a large-scale scientific application developed for tightly-coupled parallel machines is adapted to the distributed execution environment of the information Power Grid (IPG). A brief overview of the IPG and a description of the computational fluid dynamics (CFD) algorithm are given. The Globus metacomputing toolkit is used as the enabling device for the geographically-distributed computation. Modifications related to latency hiding and load balancing were required for an efficient implementation of the CFD application in the LPG environment. Performance results on a pair of SGI Origin 2000 machines indicate that real scientific applications can be effectively implemented on the IPG; however a significant amount of continued effort is required to make such an environment useful and accessible to scientists and engineers. C1 NASA, Ames Res Ctr, NAS Div, Moffett Field, CA 94035 USA. RP Barnard, S (reprint author), NASA, Ames Res Ctr, NAS Div, Moffett Field, CA 94035 USA. NR 15 TC 7 Z9 7 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 0-7695-0087-0 PY 1999 BP 60 EP 67 DI 10.1109/FMPC.1999.750585 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BM59P UT WOS:000079197000007 ER PT B AU Frumkin, M Yan, J AF Frumkin, M Yan, J GP IEEE COMP SOC IEEE COMP SOC TI HPF implementation of ARC3D SO FRONTIERS '99 - THE SEVENTH SYMPOSIUM ON THE FRONTIERS OF MASSIVELY PARALLEL COMPUTATION, PROCEEDINGS LA English DT Proceedings Paper CT 7th Symposium on the Frontiers of Massively Parallel Computation (Frontiers 99) CY FEB 21-25, 1999 CL ANNAPOLIS, MD SP IEEE Comp Soc Tech Comm Comp Architecture, USRA, CESDIS, NASA Goddard Space Flight Ctr AB We present an HPF implementation of ARC3D code along with the profiling and performance data on SGI Origin 2000. Advantages and limitations of HPF as a parallel programming language for CFD applications are discussed. For achieving good performance results we used the data distributions optimized for implementation of implicit and explicit operators of the solver and boundary conditions. We compare the results with MPI and directive based implementations. C1 NASA, Ames Res Ctr, Numer Aerosp Simulat Syst Div, Moffett Field, CA 94035 USA. RP Frumkin, M (reprint author), NASA, Ames Res Ctr, Numer Aerosp Simulat Syst Div, Moffett Field, CA 94035 USA. NR 15 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 BN 0-7695-0087-0 PY 1999 BP 81 EP 88 DI 10.1109/FMPC.1999.750587 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BM59P UT WOS:000079197000009 ER PT B AU Ma, KL AF Ma, KL GP IEEE COMP SOC IEEE COMP SOC TI Parallel rendering of 3D AMR data on the SGI/Cray T3E SO FRONTIERS '99 - THE SEVENTH SYMPOSIUM ON THE FRONTIERS OF MASSIVELY PARALLEL COMPUTATION, PROCEEDINGS LA English DT Proceedings Paper CT 7th Symposium on the Frontiers of Massively Parallel Computation (Frontiers 99) CY FEB 21-25, 1999 CL ANNAPOLIS, MD SP IEEE Comp Soc Tech Comm Comp Architecture, USRA, CESDIS, NASA Goddard Space Flight Ctr AB This paper describes work-in-progress on developing parallel visualization strategies for 3D Adaptive Mesh Refinement (AMR) data. AMR is a simple and powerful tool for modeling many important scientific and engineering problems. However visualization tools for 3D AMR data are not generally available. Converting AMR data onto a uniform mesh would result in high storage requirements, and rendering the uniform-mesh data on an average graphics workstation can be painfully slow if not impossible. The adaptive nature of the embedded mesh demands sophisticated visualization calculations. In this work, we compare the performance and storage requirements of a parallel volume renderer for regular-mesh data with a new parallel renderer based on adaptive sampling. While both renderers can achieve interactive visualization, the new approach offers significant performance gains, as indicated by our experiments on the SGI/Cray T3E. C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. RP NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Mail Stop 403, Hampton, VA 23681 USA. EM kma@icase.edu NR 24 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 BN 0-7695-0087-0 PY 1999 BP 138 EP 145 DI 10.1109/FMPC.1999.750593 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BM59P UT WOS:000079197000015 ER PT B AU Tilton, JC AF Tilton, JC GP IEEE COMP SOC IEEE COMP SOC TI A recursive PVM implementation of an image segmentation algorithm with performance results comparing the HIVE and the Cray T3E SO FRONTIERS '99 - THE SEVENTH SYMPOSIUM ON THE FRONTIERS OF MASSIVELY PARALLEL COMPUTATION, PROCEEDINGS LA English DT Proceedings Paper CT 7th Symposium on the Frontiers of Massively Parallel Computation (Frontiers 99) CY FEB 21-25, 1999 CL ANNAPOLIS, MD SP IEEE Comp Soc Tech Comm Comp Architecture, USRA, CESDIS, NASA Goddard Space Flight Ctr AB A recursive PVM (Parallel Virtual Machine) implementation of a high quality but computationally intensive image segmentation approach is described and the performance of the algorithm on the HIVE and on the Gray T3E is contrasted. The image segmentation algorithm, which is designed for the analysis of multispectral or hyperspectral remotely sensed imagery data, is a hybrid of region growing and spectral clustering that produces a hierarchical set of image segmentations based on detected natural convergence points. The HIVE is a Beowulf-class parallel computer consisting of 66 Pentium Pro PCs (64 slaves and 2 controllers) with 2 processors per PC (for 128 total slave processors) which was developed and assembled by the Applied Information Sciences Branch at NASA's Goddard Space Flight Center. The Gray T3E is a supercomputer with 512 available processors, which is installed at the NASA Center for Computational Science at NASA's Goddard Space Flight Center. Timing results on Landsat Multispectral Scanner data show that the algorithm runs approximately 1.5 times faster on the HIVE, even though the HIVE is some 86 times less costly than the Gray T3E. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tilton, JC (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 935, Greenbelt, MD 20771 USA. NR 10 TC 6 Z9 6 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 0-7695-0087-0 PY 1999 BP 146 EP 153 DI 10.1109/FMPC.1999.750594 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BM59P UT WOS:000079197000016 ER PT B AU Dorband, J Kouatchou, J Michalakes, J Ranawake, U AF Dorband, J Kouatchou, J Michalakes, J Ranawake, U GP IEEE COMP SOC IEEE COMP SOC TI Implementing MM5 on NASA Goddard space flight center computing systems: a performance study SO FRONTIERS '99 - THE SEVENTH SYMPOSIUM ON THE FRONTIERS OF MASSIVELY PARALLEL COMPUTATION, PROCEEDINGS LA English DT Proceedings Paper CT 7th Symposium on the Frontiers of Massively Parallel Computation (Frontiers 99) CY FEB 21-25, 1999 CL ANNAPOLIS, MD SP IEEE Comp Soc Tech Comm Comp Architecture, USRA, CESDIS, NASA Goddard Space Flight Ctr AB We analyze and test the performance of the fifth-generation PSU/NCAR mesoscale model MM5 on parallel computers at NASA Goddard Space Flight Center. We show hour MM5 code scales on the Gray J90, the Gray T3E and a cluster of PCs. More precisely, we are interested in finding the elapsed time, load balancing, speedup, number of floating point operations per second, and performance versus cost. Results obtained with two test problems show the efficiency of MM5 on the above computers especially with large size problems. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dorband, J (reprint author), NASA, Goddard Space Flight Ctr, Code 935, Greenbelt, MD 20771 USA. RI Koutachou, Jules/D-4773-2016 OI Koutachou, Jules/0000-0002-5525-9875 NR 6 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 BN 0-7695-0087-0 PY 1999 BP 200 EP 207 DI 10.1109/FMPC.1999.750601 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BM59P UT WOS:000079197000023 ER PT S AU Sharma, PK Narayanan, SR Hickey, GS AF Sharma, PK Narayanan, SR Hickey, GS BE Blitz, JP Little, CB TI Assessment of a thermally regenerative battery concept utilizing intercalation phenomena in graphite SO FUNDAMENTAL AND APPLIED ASPECTS OF CHEMICALLY MODIFIED SURFACES SE ROYAL SOCIETY OF CHEMISTRY SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 7th International Symposium on Chemically Modified Surfaces CY JUN 24-28, 1998 CL NORTHWESTERN UNIV, EVANSTON, IL HO NORTHWESTERN UNIV AB Graphite is known to form intercalation compounds with halogens, such as bromine, and with alkali metals, such as potassium, cesium or lithium. The guest species enter the space between uniform layers of graphite atoms and form weak compounds at room temperature. The intercalation of such species in graphite is also associated with charge effects on the graphite as well as the intercalated species. One may conceptualize a battery based on this phenomenon in which graphite electrodes capable of undergoing intercalation reactions are immersed in a nonaqueous solution of a salt such as lithium bromide. The two electrodes are separated by an ion exchange membrane impermeable to bromine or Br-3(-) anions. The intercalation of bromine into the graphite cathode leads to net power output. Since intercalation of bromine in graphite is thermally reversible, the battery can be recharged by simply heating the cathode to a temperature sufficient to drive the bromine out of the graphite. In principal, the battery can also be recharged electrochemically. The critical step to verify this electro-regenerative battery concept was identified as CBr + e(-) double right arrow Br- + C Experimentation was carried out using an electrochemical cell and bromine-intercalated graphite to verify that the above reaction step can occur electrochemically. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sharma, PK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 2 U2 5 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0260-6291 BN 0-85404-714-X J9 ROY SOC CH PY 1999 IS 235 BP 311 EP 317 DI 10.1533/9781845698591.311 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Polymer Science SC Chemistry; Materials Science; Polymer Science GA BR35Z UT WOS:000166187600028 ER PT B AU Yang, TC Durante, M George, KA Yamada, S AF Yang, TC Durante, M George, KA Yamada, S BE BaumstarkKhan, C Kozubek, S Horneck, G TI Genomic alterations in radiogenic cell transformation SO FUNDAMENTALS FOR THE ASSESSMENT OF RISKS FROM ENVIRONMENTAL RADIATION SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SUB-SER 2, ENVIRONMENTAL SECURITY LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Fundamentals for the Assessment of Risks from Environmental Radiation CY OCT 06-10, 1997 CL BRNO, CZECH REPUBLIC SP NATO ID FISSION-SPECTRUM NEUTRONS; PROGENY ALPHA-PARTICLES; X SKIN FIBROBLAST; C3H 10T1/2 CELLS; NEOPLASTIC TRANSFORMATION; ONCOGENIC TRANSFORMATION; BIOLOGICAL EFFECTIVENESS; EMBRYO CELLS; C-MYC; CYCLE AB For risk assessment, carcinogenic effects of radiation is very important to know, since most people are exposed to relatively low doses. Various experimental results indicate that cancer has cellular origin, and cultured mammalian cells have been used as a model system to study the radiation responses and the mechanism(s) of tumorigenesis at molecular and cellular level. Recent investigations focus on identifying the sensitive phase(s) of cell cycle and type(s) of genomic alteration which can be important in radiogenic cell transformation. Significant enhancement of sensitivity in G2/M was observed for X- and gamma-rays, but not for high-LET radiation. The role of chromosomal aberrations and cancer genes, including both oncogenes and tumor suppressor genes, in neoplastic transformation by ionizing radiation has been examined. Despite extensive efforts, there is no consistent results as to which oncogene(s) may be involved in radiation cell transformation. Cell fusion studies suggest that the transforming gene(s) is recessive. Some investigations have observed alterations in oncogene(s) in radiation transformed cells. These results, however, were not found in different cell systems. In addition to cancer gene studies, cytogenetic analyses of transformed cells were performed by many investigators and significant progress has been made. Common loss or translocation of specific chromosomes were detected in radiation transformed or tumor cells. Also genomic instability was observed in irradiated cells in culture. Overall the role of oncogenes in radiation cell transformation remains unclear. The tumor suppressor genes are likely to be involved in radiation carcinogenesis but are yet to be identified. Complex exchanges of chromosomes, which can be effectively induced by high-LET heavy ions, may be important genetic alterations in radiation cell transformation. Further studies on the relationship between chromosomal alterations and genomic instability and/or inactivation of tumor suppressor genes are warranted. C1 NASA, Lyndon B Johnson Space Ctr, Radiat Biophys Lab, Houston, TX 77058 USA. RP Yang, TC (reprint author), NASA, Lyndon B Johnson Space Ctr, Radiat Biophys Lab, Houston, TX 77058 USA. RI Durante, Marco/K-1315-2014 NR 30 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5667-5 J9 NATO ASI 2 PY 1999 VL 55 BP 281 EP 288 PG 8 WC Biophysics; Genetics & Heredity SC Biophysics; Genetics & Heredity GA BN32D UT WOS:000081618100036 ER PT J AU Diaz, FRC AF Diaz, FRC TI Research status of the Variable Specific Impulse Magnetoplasma Rocket SO FUSION TECHNOLOGY LA English DT Article; Proceedings Paper CT 1998 International Conference on Open Magnetic Systems for Plasma Confinement CY JUL 27-31, 1998 CL BUDKER INST NUCL PHYS, NOVOSIBIRSK, RUSSIA SP Int Atom Energy Agcy HO BUDKER INST NUCL PHYS AB The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is described. As an open-ended, RF-heated, mirror-like plasma device, the system provides access to very high and variable plasma exhaust velocities of interest in high-speed interplanetary propulsion. The three-stage system is highly asymmetric and its value rests more in its capability as a power amplifier than as a plasma confinement device. During operation, a low-temperature, high-density plasma is generated in an injector which delivers it axially to a central heating stage. Once there, the flow is further heated to the desired conditions by ion cyclotron resonance techniques before exhausting it through a magnetic nozzle to provide modulated thrust. The system has been under study since 1980. At present, a multi-center theoretical and experimental program is under way, involving several research groups in the United States and which focuses on the development of the physics and engineering of these devices. This paper provides a status report of these activities, review the applicability of the technology, and examine new areas which should be addressed in the future. C1 NASA, Lyndon B Johnson Space Ctr, Adv Space Prop Lab, Houston, TX 77059 USA. RP Diaz, FRC (reprint author), NASA, Lyndon B Johnson Space Ctr, Adv Space Prop Lab, 13000 Space Ctr Blvd, Houston, TX 77059 USA. NR 11 TC 9 Z9 9 U1 1 U2 2 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD JAN PY 1999 VL 35 IS 1T BP 87 EP 93 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 155QY UT WOS:000077958900012 ER PT J AU Squire, JP Chang, FR Baity, FW Barber, GC Carter, MD Goulding, RH Sparks, D McCaskill, G Ilin, AV Bengtson, RD Bussell, RG Jacobson, VT Glover, TW AF Squire, JP Chang, FR Baity, FW Barber, GC Carter, MD Goulding, RH Sparks, D McCaskill, G Ilin, AV Bengtson, RD Bussell, RG Jacobson, VT Glover, TW TI Experimental status of the development of a variable specific impulse magnetoplasma rocket SO FUSION TECHNOLOGY LA English DT Article; Proceedings Paper CT 1998 International Conference on Open Magnetic Systems for Plasma Confinement CY JUL 27-31, 1998 CL BUDKER INST NUCL PHYS, NOVOSIBIRSK, RUSSIA SP Int Atom Energy Agcy HO BUDKER INST NUCL PHYS ID PLASMA AB The Advanced Space Propulsion Laboratory (ASPL) is developing a Variable Specific Impulse Magnetoplasma Rocket(VASIMR)(1) using a Radio Frequency (RF) heated magnetic mirror operated asymmetrically. The system comprises of three stages: 1) plasma ionization and injection into the magnetic system; 2) ion heating by action of Ion Cyclotron Resonance Heating (ICRH); 3) plasma exhaust through a magnetic nozzle. The central experimental device is a small versatile tandem mirror configured system. The system can also be easily reconfigured to operate as a simple mirror. The total length of the device is 3.2 m, and the maximum magnetic field is 3.0 T. The exhaust end connects to a 5 m(3) vacuum chamber where we are installing a 40,000 liter/second pumping capacity. Radio frequency power is available at approximately 3 MHz at up to 200 kW. A set of plasma diagnostics is being developed and installed, starting with two fast reciprocating probes, one quadruple Langmuir and one Mach(2). We are now evaluating the use of a helicon(3) RF plasma source for an efficient ionization stage of the system. Initial results from experiments using a single double-half turn antenna are presented. In addition, we are exploring the use of a Lorentz Force Accelerator (LFA) as a plasma injector source.(4). C1 Rice Univ, NASA, JSC, Adv Space Prop Lab, Houston, TX 77059 USA. Oak Ridge Natl Lab, San Diego, CA 92186 USA. Lockheed Martin Space Mission Syst & Serv, Houston, TX 77058 USA. Univ Texas, Dept Phys, Austin, TX 78712 USA. RP Squire, JP (reprint author), Rice Univ, NASA, JSC, Adv Space Prop Lab, 13000 Space Ctr Blvd, Houston, TX 77059 USA. NR 12 TC 4 Z9 4 U1 2 U2 3 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD JAN PY 1999 VL 35 IS 1T BP 243 EP 247 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 155QY UT WOS:000077958900042 ER PT J AU Ilin, AV Diaz, FRC Squire, JP Carter, MD AF Ilin, AV Diaz, FRC Squire, JP Carter, MD TI Monte-Carlo particle dynamics in a Variable Specific Impulse Magnetoplasma Rocket SO FUSION TECHNOLOGY LA English DT Article; Proceedings Paper CT 1998 International Conference on Open Magnetic Systems for Plasma Confinement CY JUL 27-31, 1998 CL BUDKER INST NUCL PHYS, NOVOSIBIRSK, RUSSIA SP Int Atom Energy Agcy HO BUDKER INST NUCL PHYS AB The self-consistent mathematical model in Variable Specific impulse Magnetoplasma Rocket (VASIMR)(1) is examined. Of particular importance is the effect of a magnetic nozzle in enhancing the axial momentum of the exhaust. Also, different geometries and rocket asymmetries are considered. The magnetic configuration is modeled with an adaptable mesh, which increases accuracy without compromising the speed of the simulation. The single particle trajectories are integrated with an adaptive time-scheme, which can quickly solve extensive Monte-Carlo simulations for systems of hundred thousands of particles in a reasonable time (1-2 hours) and without the need for a powerful supercomputer. C1 Lockheed Martin Space, Mission Syst & Serv, Houston, TX 77058 USA. NASA, JSC, Adv Space Prop Lab, Houston, TX 77059 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Ilin, AV (reprint author), Lockheed Martin Space, Mission Syst & Serv, 6700 Bay Area Blvd, Houston, TX 77058 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD JAN PY 1999 VL 35 IS 1T BP 330 EP 334 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 155QY UT WOS:000077958900060 ER PT B AU Borne, KD Bushouse, H Colina, L Lucas, RA AF Borne, KD Bushouse, H Colina, L Lucas, RA BE Merritt, D Sellwood, JA Valluri, M TI Dynamics of ultraluminous galaxies SO GALAXY DYNAMICS: A RUTGERS SYMPOSIUM SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Rutgers Symposium on Galaxy Dynamics CY AUG 08-12, 1998 CL RUTGERS UNIV, PISCATAWAY, NJ SP Rutgers Univ HO RUTGERS UNIV C1 NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Greenbelt, MD 20771 USA. RP Borne, KD (reprint author), NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Greenbelt, MD 20771 USA. EM borne@xfiles.gsfc.nasa.gov NR 8 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 1-58381-007-2 J9 ASTR SOC P PY 1999 VL 182 BP 461 EP 462 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN98P UT WOS:000083761200119 ER PT S AU Nakagawa, T Kii, T Fujimoto, R Miyazaki, T Inoue, H Ogasaka, Y Arnaud, K Kawabe, R AF Nakagawa, T Kii, T Fujimoto, R Miyazaki, T Inoue, H Ogasaka, Y Arnaud, K Kawabe, R BE Barnes, JE Sanders, DB TI ASCA observations of luminous infrared galaxies - Evolution from starburst to AGN? SO GALAXY INTERACTIONS AT LOW AND HIGH REDSHIFT SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 186th Symposium of the International-Astronomical-Union on Galaxy Interaction at Low and high Redshifts CY AUG 26-30, 1997 CL KYOTO, JAPAN SP Int Astron Union C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Nobeyama Radio Observ, Minamisa Ku, Nagano 38413, Japan. RP Nakagawa, T (reprint author), Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229, Japan. NR 5 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-5832-5 J9 IAU SYMP PY 1999 IS 186 BP 341 EP 344 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ09W UT WOS:000087175400081 ER PT S AU Stockman, HS Mather, J AF Stockman, HS Mather, J BE Barnes, JE Sanders, DB TI NGST: Seeing the first stars and galaxies form SO GALAXY INTERACTIONS AT LOW AND HIGH REDSHIFT SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 186th Symposium of the International-Astronomical-Union on Galaxy Interaction at Low and high Redshifts CY AUG 26-30, 1997 CL KYOTO, JAPAN SP Int Astron Union ID REIONIZATION; UNIVERSE AB The Next Generation Space Telescope (NGST) is a key element in NASA's Origins program. The primary goals for the NGST are observing the origins of stars, galaxies, and the elements that are necessary for life. To reach those goals, the telescope must work in the near and mid-infrared at wavelengths where the Earth's atmosphere outshines the distant galaxies by up to 8 orders of magnitude. NASA, industry, US astronomers and international collaborators have completed the initial feasibility study and have begun the development of the technologies required to make the mission affordable and ready to launch by 2007. We describe the three missions developed in the feasibility studies: a 6 m monolithic telescope in a 1 x 3 AU elliptical orbit, and two 8 m deployable telescopes put into L2 halo orbits. All three telescopes are radiation cooled to temperatures of 30-60 K. All three achieve point-source imaging sensitivities of 1 nanoJansky in a 3 hr exposure. Such sensitivity and diffraction-limited imaging can see the birth of stellar clusters at redshifts of z = 10 - 20 - even before the universe was reionized. We also illustrate NGST's potential for studying the detailed interactions and mergers of galaxies during the peak of metal production at redshifts of z = 1 - 2, an epoch when dust may mask much of the galactic light and the regions of ongoing star formation. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stockman, HS (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-5832-5 J9 IAU SYMP PY 1999 IS 186 BP 493 EP 499 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ09W UT WOS:000087175400144 ER PT B AU Bonnell, JT Norris, JP AF Bonnell, JT Norris, JP BE Poutanen, J Svensson, R TI On the brightness distribution of soft, "no high energy emission", gamma-ray bursts SO GAMMA-RAY BURSTS: THE FIRST THREE MINUTES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Gamma-Ray Bursts - The First Three Minutes CY FEB 06-11, 1999 CL GRAFTAVALLEN, SWEDEN SP Nord Inst Theoret Phys, Swedish Nat Sci Res Council, Anna-Greta & Holger Crafoord Fund ID BATSE; IDENTIFICATION; DIVERSITY AB The inhomogeneous brightness distribution of BATSE detected gamma-ray bursts is considered a natural consequence of their cosmological origin. However, subclasses of gamma-ray bursts have been shown to have significantly more homogeneous brightness distributions. Pendleton et al. (1997) have found such a result for gamma-ray bursts with no detectable emission at energies > 300 keV. Accordingly, it has been suggested that these no high energy (NHE) emission bursts represent an underluminous population of nearby sources. A distinct homogeneous NHE brightness distribution has also been considered as evidence for beaming of different spectral components of the prompt burst emission. We synthesize brightness distributions of gamma-ray bursts based on a sample of typical bright bursts with intrinsic high energy emission and find that the resulting synthetic NHE bursts do indeed have a more nearly homogeneous intensity distribution when an appropriate decrease in signal to noise and redshifted spectrum is incorporated. The NHE class of gamma-ray bursts is therefore likely due to brightness bias. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bonnell, JT (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 23 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 1-58381-016-1 J9 ASTR SOC P PY 1999 VL 190 BP 263 EP 270 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP44C UT WOS:000085157500018 ER PT B AU Bartolotta, PA Krause, DL AF Bartolotta, PA Krause, DL BE KIM, YW Dimiduk, DM Loretto, MH TI Titanium aluminide applications in the high speed civil transport SO GAMMA TITANIUM ALUMINIDES 1999 LA English DT Proceedings Paper CT 2nd International Symposium on Gamma Titanium Aluminides held in Conjunction with the TMS 1999 Annual Meeting CY MAR 01-04, 1999 CL SAN DIEGO, CA SP TMSSMD Titanium Comm, AFRL, GKSS, HOWMET, IRC, Kyoto Univ, GE AB It is projected that within the next two decades, overseas air travel will increase to over 600,000 passengers per day. The High Speed Civil Transport (HSCT) is a second-generation supersonic commercial aircraft proposed to meet this demand. The expected fleet of 500 to 1500 aircraft is required to meet EPA environmental goals; the HSCT propulsion system requires advanced technologies to reduce exhaust and noise pollution. A part of the resultant strategy for noise attenuation is the use of an extremely large exhaust nozzle. In the nozzle, several critical components are fabricated from titanium aluminide: the divergent flap uses wrought gamma; the nozzle sidewall is a hybrid fabrication of both wrought gamma face sheet and cast gamma substructure. This paper describes the HSCT program and the use of titanium aluminide for its components. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Bartolotta, PA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 46 Z9 46 U1 0 U2 2 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-451-8 PY 1999 BP 3 EP 10 PG 8 WC Materials Science, Multidisciplinary; Mechanics; Metallurgy & Metallurgical Engineering SC Materials Science; Mechanics; Metallurgy & Metallurgical Engineering GA BP80P UT WOS:000086245200001 ER PT B AU Haith, GL Lohn, JD Colombano, SP Stassinopoulos, D AF Haith, GL Lohn, JD Colombano, SP Stassinopoulos, D BE Banzhaf, W Daida, J Eiben, AE Garzon, MH Honavar, V Jakiela, M Smith, RE TI Coevolution for problem simplification SO GECCO-99: PROCEEDINGS OF THE GENETIC AND EVOLUTIONARY COMPUTATION CONFERENCE LA English DT Proceedings Paper CT Genetic and Evolutionary Computation Conference (GECCO-99) at the 8th International Conference on Genetic Algorithms/4th Annual Genetic Programming Conference CY JUL 13-17, 1999 CL ORLANDO, FL SP European Network Excellence Evolutionary Comp, Evolut Artificielle, ICES, Int Soc Adapt Behav, Amer Assoc Artificial Intelligence AB This paper explores a coevolutionary approach applicable to difficult problems with limited failure/success performance feedback. Like familiar "predator-prey" frameworks this algorithm evolves two populations of individuals - the solutions (predators) and the problems (prey). The approach extends previous work by rewarding only the problems that match their difficulty to the level of solution competence. In complex problem domains with limited feedback, this "tractability constraint" helps provide an adaptive fitness gradient that effectively differentiates the candidate solutions. The algorithm generates selective pressure toward the evolution of increasingly competent solutions by rewarding solution generality and uniqueness and problem tractability and difficulty. Relative (inverse-fitness) and absolute (static objective function) approaches to evaluating problem difficulty are explored and discussed. On a simple control task, this coevolutionary algorithm was found to have significant advantages over a genetic algorithm with either a static fitness function or a fitness function that changes on a hand-tuned schedule. C1 NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. RP Haith, GL (reprint author), NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA BN 1-55860-611-4 PY 1999 BP 244 EP 251 PG 8 WC Computer Science, Theory & Methods SC Computer Science GA BQ96Q UT WOS:000165164700032 ER PT B AU Stoica, A Lazaro, CS Keymeulen, D Hayworth, K AF Stoica, A Lazaro, CS Keymeulen, D Hayworth, K BE Banzhaf, W Daida, J Eiben, AE Garzon, MH Honavar, V Jakiela, M Smith, RE TI Evolution of CMOS circuits in simulations and directly in hardware on a programmable chip SO GECCO-99: PROCEEDINGS OF THE GENETIC AND EVOLUTIONARY COMPUTATION CONFERENCE LA English DT Proceedings Paper CT Genetic and Evolutionary Computation Conference (GECCO-99) at the 8th International Conference on Genetic Algorithms/4th Annual Genetic Programming Conference CY JUL 13-17, 1999 CL ORLANDO, FL SP European Network Excellence Evolutionary Comp, Evolut Artificielle, ICES, Int Soc Adapt Behav, Amer Assoc Artificial Intelligence AB The paper introduces an approach to automated synthesis of CMOS circuits, based on evolution on a Programmable Transistor Array (PTA). The PTA is a reconfigurable architecture that allows evolutionary synthesis in simulations as well as on a reconfigurable chip implementing the PTA. Thus, the PTA allows, for the first time, analog circuits obtained by evolutionary design to be immediately validated in hardware on the programmable PTA chip. The paper describes a software experiment showing evolutionary synthesis of a circuit with a desired DC characteristic. The hardware implementation of a PTA chip is then described, and the same evolutionary experiment is performed directly on the chip demonstrating circuit synthesis/self-configuration in hardware. The experiment shows that some solutions obtained in simulated evolutions may not be valid when programmed in hardware. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stoica, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA BN 1-55860-611-4 PY 1999 BP 1198 EP 1203 PG 6 WC Computer Science, Theory & Methods SC Computer Science GA BQ96Q UT WOS:000165164700201 ER PT B AU Desjarlais, LM Akbarzadeh-T, MR Wright, CW AF Desjarlais, LM Akbarzadeh-T, MR Wright, CW BE Banzhaf, W Daida, J Eiben, AE Garzon, MH Honavar, V Jakiela, M Smith, RE TI Control system optimization using genetic algorithms with the SoftLab toolkit SO GECCO-99: PROCEEDINGS OF THE GENETIC AND EVOLUTIONARY COMPUTATION CONFERENCE LA English DT Proceedings Paper CT Genetic and Evolutionary Computation Conference (GECCO-99) at the 8th International Conference on Genetic Algorithms/4th Annual Genetic Programming Conference CY JUL 13-17, 1999 CL ORLANDO, FL SP European Network Excellence Evolutionary Comp, Evolut Artificielle, ICES, Int Soc Adapt Behav, Amer Assoc Artificial Intelligence AB This paper presents techniques for using genetic algorithms within the SoftLab software environment to automate the optimization of control systems. SoftLab is a framework for the design and simulation of control systems, using soft computing components. It allows users to construct systems by connecting computational modules into dataflow networks. We discuss the set of modules provided for implementing genetic algorithms and demonstrate how even the problem-specific aspects of the genetic algorithm can be easily specified through interpreted scripts, avoiding the need to compile or link in order to set up a new test problem. C1 Univ New Mexico, NASA, Ctr Autonomous Control Engn, Albuquerque, NM 87131 USA. RP Desjarlais, LM (reprint author), Univ New Mexico, NASA, Ctr Autonomous Control Engn, Albuquerque, NM 87131 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA BN 1-55860-611-4 PY 1999 BP 1774 EP 1774 PG 1 WC Computer Science, Theory & Methods SC Computer Science GA BQ96Q UT WOS:000165164700303 ER PT J AU Jahnke, LL Summons, RE Hope, JM des Marais, DJ AF Jahnke, LL Summons, RE Hope, JM des Marais, DJ TI Carbon isotopic fractionation in lipids from methanotrophic bacteria II: The effects of physiology and environmental parameters on the biosynthesis and isotopic signatures of biomarkers SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID METHYLOCOCCUS-CAPSULATUS BATH; SOLUBLE METHANE MONOOXYGENASE; FATTY-ACIDS; METHYLOSINUS-TRICHOSPORIUM; PROKARYOTIC TRITERPENOIDS; FAMILY METHYLOCOCCACEAE; OXIDIZING BACTERIA; ISOPRENIC UNITS; MONO-OXYGENASE; OXIDATION AB Controls on the carbon isotopic signatures of methanotroph biomarkers have been further explored using cultured organisms. Growth under conditions which select far the membrane-bound particulate form of the methane monooxygenase enzyme (pMMO) leads to a significantly higher isotopic fractionation than does growth based on the soluble isozyme in both RuMP and serine pathway methanotrophs; in an RuMP type the Delta delta(13)C(biomass) equaled -23.9 parts per thousand for pMMO and -12.6 parts per thousand for sMMO. The distribution of biomarker lipids does not appear to be significantly affected by the dominance of one or the other MMO type and their isotopic compositions generally track those of the parent biomass. The C-13 fractionation behaviour of serine pathway methanotrophs is very complex, reflecting the assimilation of both methane and carbon dioxide and concomitant dissimilation of methane-derived carbon. A limitation in CH4 availability leads to the production of biomass which is C-13-enriched with respect to both carbon substrates and this occurs irrespective of MMO type. This startling result indicates that there must be an additional fractionation step downstream from the MMO reaction which leads to incorporation of C-13-enriched carbon at the expense of dissimilation of C-13-depleted CO2. In these organisms, polyisoprenoid lipids are C-13-enriched compared to polymethylenic lipid which is the reverse of that found in the RuMP types. Serine cycle hopanoids, for example, can vary anywhere from 12 parts per thousand depleted to 10 parts per thousand enriched with respect to the CH4 substrate depending on its concentration. Decrease in growth temperature caused an overall increase in isotopic fractionation. In the total biomass, this effect tended to be masked by physiological factors associated with the type of organism and variation in the bulk composition. The effect was, however, clearly evident when monitoring the C-13 signature of total lipid and individual biomarkers. Our results demonstrate that extreme carbon isotopic depletion in field samples and fossil biomarker lipids can be indicative of methanotrophy but the converse is not always true. For example, the hopanoids of a serine cycle methanotroph may be isotopically enriched by more than 10 parts per thousand compared to the substrate methane when the latter is limiting. In other words, hopanoids from some methanotrophs such as M. trichosporium would be indistinguishable from those of cyanobacteria or heterotrophic bacteria on the basis of either chemical structure or carbon isotopic signature. Copyright (C) 1999 Elsevier Science Ltd. C1 NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. Australian Geol Survey Org, Canberra, ACT 2601, Australia. RP Jahnke, LL (reprint author), NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. NR 71 TC 95 Z9 96 U1 1 U2 27 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JAN PY 1999 VL 63 IS 1 BP 79 EP 93 DI 10.1016/S0016-7037(98)00270-1 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 194WQ UT WOS:000080218100007 PM 11541777 ER PT J AU Farrell, WM Hess, RA MacDowall, RJ AF Farrell, WM Hess, RA MacDowall, RJ TI O-mode emission at the Io torus: A real or virtual source? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ULYSSES; RADIO AB We examine the nature of an ordinary (o-made) emission observed near the Io plasma torus during the 1992 Ulysses encounter with Jupiter. The emission appears to intensify by factors of 10-100 in local torus density depletions. We: examine whether these intensifications are due to local generation within the density depletion or reflection of a remotely generated emission. Based on the observed emission spectra, we find that a virtual source is most consistent with the character of the local enhancements. This virtual source observation near the dense toms may de relevant to the understanding of a newly discovered torus-related hectometric emission by the Galileo orbiter. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Raytheon STX, Lanham, MD USA. RP Farrell, WM (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI MacDowall, Robert/D-2773-2012; Farrell, William/I-4865-2013 NR 12 TC 3 Z9 3 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 1 PY 1999 VL 26 IS 1 BP 1 EP 4 DI 10.1029/1998GL900178 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 158MF UT WOS:000078118700001 ER PT J AU Keim, ER McKeen, SA Gao, RS Donnelly, SG Wamsley, RC Del Negro, LA Fahey, DW Hanisco, TF Lanzendorf, EJ Proffitt, MH Margitan, JJ Hintsa, EJ Jaegle, L Webster, CR May, RD Scott, DC Salawitch, RJ Wilson, JC McElroy, CT Atlas, EL Flocke, F Bui, TP AF Keim, ER McKeen, SA Gao, RS Donnelly, SG Wamsley, RC Del Negro, LA Fahey, DW Hanisco, TF Lanzendorf, EJ Proffitt, MH Margitan, JJ Hintsa, EJ Jaegle, L Webster, CR May, RD Scott, DC Salawitch, RJ Wilson, JC McElroy, CT Atlas, EL Flocke, F Bui, TP TI NOy partitioning from measurements of nitrogen and hydrogen radicals in the upper troposphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOWER STRATOSPHERE; FATE AB Recent studies using NO, NOy, OH and HO2 (HOx) observations have postulated acetone and convection of peroxides as significant sources of HOx in the upper troposphere (UT). This work focuses on the effect these additional HOx sources have on the modeled NOy partitioning and comparisons of the modeled NOx/NOy ratio to observations. The measured NOx/NOy ratio is usually much higher than predicted regardless of the presence of acetone in the model. The exception occurs for air parcels having low NOy and O-3 values. For these air parcels the measured NOx/NOy ratio is much Power than the calculated ratio unless acetone is included in the model. In all cases acetone increases the fraction of NOy that is peroxy acetyl nitrate (PAN) from typical values of much less than 0.1 to values as high as 0.35. Including acetone also reduces the scatter in a comparison between modeled and observed NOx/NOy ratios. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Harvard Univ, Dept Chem, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Denver, Dept Engn, Denver, CO 80208 USA. Atmospher Environm Serv, Downsview, ON M3H 5T4, Canada. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Keim, ER (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Salawitch, Ross/B-4605-2009; 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; Fahey, David/0000-0003-1720-0634 NR 17 TC 9 Z9 9 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 1999 VL 26 IS 1 BP 51 EP 54 DI 10.1029/1998GL900219 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 158MF UT WOS:000078118700014 ER PT J AU Mlynczak, MG Zhou, DK Lopez-Puertas, M Zaragoza, G Russell, JM AF Mlynczak, MG Zhou, DK Lopez-Puertas, M Zaragoza, G Russell, JM TI Kinetic requirements for the measurement of mesospheric water vapor at 6.8 mu m under non-LTE conditions SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RELAXATION; OXYGEN; H2O AB We present accuracy requirements for specific kinetic parameters used to calculate the populations and vibrational temperatures of the H2O(010) and H2O(020) states in the terrestrial mesosphere. The requirements are based on rigorous simulations of the retrieval of mesospheric water vapor profiles from measurements of water vapor infrared emission made by limb scanning instruments on orbiting satellites. Major improvements in the rate constants that describe vibration-to-vibration exchange between the H2O(010) and O-2(1) states are required in addition to improved specification of the rate of quenching of O-2(1) by atomic oxygen (O). It is also necessary to more accurately determine the yield of vibrationally excited O-2(1) resulting from ozone photolysis. A contemporary measurement of the rate of quenching of H2O(010) by N-2 and O-2 is also desirable. These rates are either highly uncertain or have never before been measured at atmospheric temperatures. The suggested improvements are necessary for the interpretation of water vapor emission measurements at 6.8 mu m to be made from a new spaceflight experiment in less than 2 years. The approach to retrieving water vapor under non-LTE conditions is also presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Utah State Univ, Logan, UT 84322 USA. CSIC, Inst Astrofis Andalucia, Granada, Spain. Univ Oxford, Dept Phys, Oxford OX1 2JD, England. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Mlynczak, MG (reprint author), NASA, Langley Res Ctr, Mail Stop 401B, Hampton, VA 23681 USA. RI Zaragoza, Guillermo/D-8412-2011; Mlynczak, Martin/K-3396-2012; Lopez Puertas, Manuel/M-8219-2013 OI Lopez Puertas, Manuel/0000-0003-2941-7734 NR 13 TC 10 Z9 10 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 1 PY 1999 VL 26 IS 1 BP 63 EP 66 DI 10.1029/1998GL900232 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 158MF UT WOS:000078118700017 ER PT J AU Zhou, DK Mlynczak, MG Lopez-Puertas, M Zaragoza, G AF Zhou, DK Mlynczak, MG Lopez-Puertas, M Zaragoza, G TI Evidence of non-LTE effects in mesospheric water vapor from spectrally-resolved emissions observed by CIRRIS-1A SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NONLOCAL THERMODYNAMIC-EQUILIBRIUM; BANDS AB Evidence of non-LTE effects in mesospheric water vapor as determined by infrared spectral emission measurements taken from the space shuttle is reported. A cryogenic Michelson interferometer in the CIRRIS-1A shuttle payload yielded high quality atmospheric infrared spectra. These measurements demonstrate the enhanced daytime emissions of H2O (020-->010) which are the result of non-LTE processes and in agreement with non-LTE models. The radiance ratios of H2O (010-->000) and (020-->010) Q(1) transitions during daytime are compared with non-LTE model calculations to assess the vibration-to-vibration exchange rate between H2O and O-2 in the mesosphere. An exchange rate of 1.2x10(-12) cm(3) s(-1) is derived. C1 Utah State Univ, Space Dynam Lab, Logan, UT 84341 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Inst Astrofis Andalucia, E-18080 Granada, Spain. Univ Oxford, Dept Phys, Oxford OX1 3PU, England. RP Zhou, DK (reprint author), Utah State Univ, Space Dynam Lab, Logan, UT 84341 USA. RI Zaragoza, Guillermo/D-8412-2011; Mlynczak, Martin/K-3396-2012; Lopez Puertas, Manuel/M-8219-2013; OI Lopez Puertas, Manuel/0000-0003-2941-7734; Zaragoza, Guillermo/0000-0002-4452-9980 NR 14 TC 11 Z9 11 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 1 PY 1999 VL 26 IS 1 BP 67 EP 70 DI 10.1029/1998GL900233 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 158MF UT WOS:000078118700018 ER PT S AU Ji, Y Yao, XS Maleki, L AF Ji, Y Yao, XS Maleki, L BE Streit, DC TI Ultra-low phase noise compact-sized x-band optoelectronic oscillator SO GIGAHERTZ DEVICES AND SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Gigahertz Devices and Systems CY SEP 20, 1999 CL BOSTON, MA SP SPIE DE optoelectronics; oscillator; DFB laser; fiber delay line; phase noise; dielectric resonator filter; frequency stability AB We report the performance of an optoelectronic oscillator (OEO) constructed with a DFB laser, a semiconductor Mach-Zehnder modulator, and a dielectric resonator based RF filter. We achieved a phase noise of -50dBc/Hz at 10Hz and -130 dBc/Hz at 10 kHz from a 10 GHz oscillation frequency, a performance comparable with that of an OEO constructed with a diode-pump YAG laser and a LiNbO3 modulator. The demonstration proves the feasibility of a high performance, low cost, and compact OEO. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ji, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 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 0-8194-3454-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3861 BP 58 EP 67 DI 10.1117/12.373021 PG 10 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BP46C UT WOS:000085206100008 ER PT J AU Parry, M Rosenzweig, C Iglesias, A Fischer, G Livermore, M AF Parry, M Rosenzweig, C Iglesias, A Fischer, G Livermore, M TI Climate change and world food security: a new assessment SO GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS LA English DT Article DE climate change; food security; crop yields AB Building on previous work quantitative estimates of climate change impacts on global food production have been made for the UK Hadley Centre's HadCM2 greenhouse gas only ensemble experiment and the more recent HadCM3 experiment (Hulme et al., 1999). The consequences for world food prices and the number of people at risk of hunger as defined by the Food and Agriculture Organisation(FAO, 1988) have also been assessed. Climate change is expected to increase yields at high and mid-latitudes, and lead to decreases at lower latitudes. This pattern becomes more pronounced as time progresses. The food system may be expected to accommodate such regional variations at the global level, with production, prices and the risk of hunger being relatively unaffected by the additional stress of climate change. By the 2080s the additional number of people at risk of hunger due to climate change is about 80 million people ( +/- 10 million depending on which of the four HadCM2 ensemble members is selected). However, some regions (particularly the arid and sub-humid tropics) will be adversely affected. A particular example is Africa, which is expected to experience marked reductions in yield, decreases in production, and increases in the risk of hunger as a result of climate change. The continent can expect to have between 55 and 65 million extra people at risk of hunger by the 2080s under the HadCM2 climate scenario. Under the HadCM3 climate scenario the effect is even more severe? producing an estimated additional 70 + million people at risk of hunger in Africa. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Univ E Anglia, Jackson Environm Inst, Norwich NR4 7TJ, Norfolk, England. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Politecn Madrid, E-28040 Madrid, Spain. Int Inst Appl Syst Anal, A-2361 Laxenburg, Austria. RP Parry, M (reprint author), Univ E Anglia, Jackson Environm Inst, Norwich NR4 7TJ, Norfolk, England. NR 27 TC 105 Z9 109 U1 5 U2 65 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0959-3780 J9 GLOBAL ENVIRON CHANG JI Glob. Environ. Change-Human Policy Dimens. PY 1999 VL 9 SU S BP S51 EP S67 DI 10.1016/S0959-3780(99)00018-7 PG 17 WC Environmental Sciences; Environmental Studies; Geography SC Environmental Sciences & Ecology; Geography GA 254HG UT WOS:000083605400005 ER PT S AU Content, D AF Content, D BE Kathman, AD TI Diffraction grating groove analysis used to predict efficiency and scatter performance SO GRADIENT INDEX, MINIATURE, AND DIFFRACTIVE OPTICAL SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Gradient Index, Miniature, and Diffractive Optical Systems CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE diffraction gratings; Hubble space telescope; atomic force microscope; microinterferometer; scattered light; Space Telescope Imaging Spectrograph ID COUPLED-WAVE ANALYSIS; RELIEF GRATINGS; X-RAY; SCALAR; INDEX AB Atomic force microscopy and other advanced metrology tools now allow detailed determination of the groove profiles and surface morphology of diffraction gratings and other diffractive structures. Modern electromagnetic models allow prediction of the efficiency performance of diffraction gratings in many applications. In addition, tools exist to predict the scatter from low roughness mirrors such as are used for ultraviolet to X-ray optical systems. We describe a program to apply these tools and software developed using commercial off the shelf tools such as IDL and PcGrate to a highly selected set of diffraction gratings developed for the HST/STIS instruments. Both efficiency and scatter predictions are compared with experimental data. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. RP Content, D (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, MC551, Greenbelt, MD 20771 USA. NR 30 TC 12 Z9 12 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 0-8194-3264-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3778 BP 19 EP 30 DI 10.1117/12.363756 PG 12 WC Optics SC Optics GA BN88E UT WOS:000083314600003 ER PT S AU Grugel, RN Lee, CP Anilkumar, AV Wang, TG Shen, XF Croll, A Bune, A AF Grugel, RN Lee, CP Anilkumar, AV Wang, TG Shen, XF Croll, A Bune, A BE Schwabe, D TI Promoting microstructural uniformity during floating-zone crystal growth SO GRAVITATIONAL EFFECTS IN MATERIALS AND FLUID SCIENCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT G0 1 Symposium of COSPAR Scientific Commission G Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res ID TENSION DRIVEN FLOW; THERMOCAPILLARY CONVECTION; VIBRATION AB It is demonstrated in floating-zone configurations utilizing silicone oil and nitrate salts that mechanically induced vibration effectively minimizes detrimental, gravity independent, thermocapillary flow. The processing parameters leading to crystal improvement and aspects of the on-going modeling effort are discussed. Plans for applying the crystal growth technique to commercially relevant materials, e.g., silicon, as well as the value of processing in a microgravity environment are presented. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. Vanderbilt Univ, Nashville, TN USA. Univ Freiburg, Inst Kristallog, D-7800 Freiburg, Germany. RP Grugel, RN (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, MS ES 75, Huntsville, AL 35812 USA. RI Croell, Arne/A-2480-2013 OI Croell, Arne/0000-0002-8673-9994 NR 17 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 10 BP 1195 EP 1198 DI 10.1016/S0273-1177(99)00719-X PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Materials Science, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Materials Science; Meteorology & Atmospheric Sciences GA BP27G UT WOS:000084542400002 ER PT S AU Grugel, RN Kim, S AF Grugel, RN Kim, S BE Schwabe, D TI Promoting uniform composite growth in directionally solidified hypermonotectic alloys SO GRAVITATIONAL EFFECTS IN MATERIALS AND FLUID SCIENCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT G0 1 Symposium of COSPAR Scientific Commission G Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res AB Liquid-liquid phase separation occurs when an alloy of hypermonotectic composition passes, at its representative temperature, into the miscibility gap. in addition to gravity driven separation, factors such as preferential wetting and coarsening preclude uniform microstructural development during controlled directional solidification (DS) processing. Several novel techniques which account for these detrimental effects and promote microstructural uniformity are reexamined. In particular, ongoing work that utilizes ultrasonic vibration in conjunction with DS is presented and discussed. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. Hoseo Univ, Dept Mat Sci & Engn, Chung Nam, South Korea. RP Grugel, RN (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, MS ES75, Huntsville, AL 35812 USA. NR 19 TC 1 Z9 1 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 10 BP 1263 EP 1266 DI 10.1016/S0273-1177(99)00730-9 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Materials Science, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Materials Science; Meteorology & Atmospheric Sciences GA BP27G UT WOS:000084542400013 ER PT S AU Michael, BP Nuth, JA Lilleleht, LU Bussoletti, E Colangeli, L Palumbo, P AF Michael, BP Nuth, JA Lilleleht, LU Bussoletti, E Colangeli, L Palumbo, P BE Schwabe, D TI A nucleation experiment in low gravity conditions: Monitoring and collection of Mg and Zn particles SO GRAVITATIONAL EFFECTS IN MATERIALS AND FLUID SCIENCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT G0 1 Symposium of COSPAR Scientific Commission G Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res AB An experiment on the nucleation and growth of solid particles from the condensation of vapor in low gravity conditions was performed onboard NASA's KC-135 Microgravity Research Aircraft. In addition to the systems to monitor relevant physical parameters, two systems have been developed and used to observe the growth process of the particles and to extract these particles for further microscopic analyses. A dynamic light scattering system is used to measure the in situ mean particle size while a second independent system allows the collection of the nucleated particles directly from the condensation front. These samples have been analyzed in the lab using Scanning Electron Microscopy (SEM). Mean particle sizes are approximately 300 nm and 150 nm for Mg and Zn particles, respectively. Evidence for particle-particle coagulation of Mg into "fractal" like clusters is seen while Zn shows no evidence for any coagulation over the conditions explored. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Virginia, Charlottesville, VA USA. Ist Univ Navale, Naples, Italy. Osservatorio Astron Capodimonte, I-80131 Naples, Italy. RP Michael, BP (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Nuth, Joseph/E-7085-2012; Michael, Patrick/N-6948-2013 OI Michael, Patrick/0000-0002-4742-4543 NR 6 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 10 BP 1273 EP 1277 DI 10.1016/S0273-1177(99)00732-2 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Materials Science, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Materials Science; Meteorology & Atmospheric Sciences GA BP27G UT WOS:000084542400015 ER PT S AU Rogers, MJB Hrovat, K Moskowitz, ME AF Rogers, MJB Hrovat, K Moskowitz, ME BE Schwabe, D TI Effects of exercise equipment on the microgravity environment SO GRAVITATIONAL EFFECTS IN MATERIALS AND FLUID SCIENCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT G0 1 Symposium of COSPAR Scientific Commission G Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res AB Numerous types of exercise equipment have flown on manned space flights to evaluate and maintain crew members' physical condition while on orbit. Vibrations associated with the use of some exercise equipment cause concern among microgravity scientists who are usually looking for a quiescent environment in which to run their experiments. We discuss the impact of aerobic (bicycle ergometer, treadmill) and non-aerobic (resistance devices) exercise on the microgravity environment of the Space Shuttle Orbiters and the Mir Space Station. In general, characteristic vibration disturbances due to ergometer exercise show the pedalling frequency at 2.5 to 3 Hz and the crew members' body rocking side-to-side at about half the pedalling frequency. For treadmill exercise, the footfall frequency on the treadmill platform can be clearly seen in the 1 to 2 Hz range, along with upper harmonics. The use of resistance exercise devices does not typically cause vibrations. Several vibration isolation systems used on the Orbiters and planned for the International Space Station are introduced. Finally, the responses of specific experiments to exercise vibrations are outlined. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Lewis Res Ctr, USRA, NCMR, Cleveland, OH 44135 USA. NASA, Lewis Res Ctr, PIMS Tal Cut, Cleveland, OH 44135 USA. Honeywell BCAS, Glendale, AZ USA. RP Rogers, MJB (reprint author), NASA, Lewis Res Ctr, USRA, NCMR, MS 110-3, Cleveland, OH 44135 USA. NR 4 TC 2 Z9 4 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 10 BP 1283 EP 1287 DI 10.1016/S0273-1177(99)00734-6 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Materials Science, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Materials Science; Meteorology & Atmospheric Sciences GA BP27G UT WOS:000084542400017 PM 11542665 ER PT S AU Antar, BN Ethridge, E Maxwell, D AF Antar, BN Ethridge, E Maxwell, D BE Schwabe, D TI Utilization of low gravity environment for measuring the viscosity of highly viscous liquids SO GRAVITATIONAL EFFECTS IN MATERIALS AND FLUID SCIENCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT G0 1 Symposium of COSPAR Scientific Commission G Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res AB The method of drop coalescence is utilized for determining the viscosity of highly undercooled liquids. Low gravity environment is necessary in order to avoid problems connected with droplet deformation due other body forces that are present under terrestrial conditions. The drop coalescence method is preferred over the drop oscillation technique since the latter method can only be applied for liquids with vanishingly small viscosities. The technique developed relies on both the highly accurate solution of the equations of motion for fluid flows as well as on data from experiments conducted in near zero gravity environment. Results are presented for method validation experiments performed recently on board the NASA/KC-135 aircraft. These experiments gave excellent results which will be discussed together with plans for implementing the method in a shuttle flight experiment. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Univ Tennessee, Inst Space, Tullahoma, TN 37388 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Antar, BN (reprint author), Univ Tennessee, Inst Space, Tullahoma, TN 37388 USA. NR 2 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 10 BP 1289 EP 1292 DI 10.1016/S0273-1177(99)00735-8 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Materials Science, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Materials Science; Meteorology & Atmospheric Sciences GA BP27G UT WOS:000084542400018 ER PT S AU Zhao, AX Narayanan, R Fripp, AL AF Zhao, AX Narayanan, R Fripp, AL BE Schwabe, D TI A 3D numerical model for flow profiles in a Bridgman tube - The effects of constant and periodic off axis orientation in a low gravity environment SO GRAVITATIONAL EFFECTS IN MATERIALS AND FLUID SCIENCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT G0 1 Symposium of COSPAR Scientific Commission G Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res AB A 3D numerical calculation is performed on a model that depicts the flow profiles due to thermo-solutal convection in a cylindrical tube. The calculations were drone with the purpose of delineating the qualitative features of the flow profiles for the cases when the container's axis is perfectly aligned with respect to the mean gravity vector and also when it changes periodically with respect to the gravity vector. It is found that the flow profiles are similar to those of the Rayleigh-Benard problem in the case of perfect alignment while a swirling pattern appears when the tube's axis is not aligned with the gravity vector. This indicates that it might be preferable to have a slight tilt in the container axis during crystal growth as swirling flow will diminish axial mixing. The solutal convection is the dominant feature of the flow and is affected considerably by the gravity level. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Zhao, AX (reprint author), Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. NR 4 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 J9 ADV SPACE RES PY 1999 VL 24 IS 10 BP 1397 EP 1402 DI 10.1016/S0273-1177(99)00752-8 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Materials Science, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Materials Science; Meteorology & Atmospheric Sciences GA BP27G UT WOS:000084542400035 ER PT B AU Frederick, SY AF Frederick, SY BE Thompson, WR TI The Anglo-German rivalry, 1890-1914 SO GREAT POWER RIVALRIES SE STUDIES IN INTERNATIONAL RELATIONS LA English DT Proceedings Paper CT Conference on Great Power Rivalries CY 1995 CL INDIANA UNIV, BLOOMINGTON, IN SP Indiana Univ HO INDIANA UNIV C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 39 TC 1 Z9 1 U1 1 U2 2 PU UNIV SOUTH CAROLINA PRESS PI COLUMBIA PA COLUMBIA, SC 29208 USA BN 1-57003-279-3 J9 STUD INT R PY 1999 BP 306 EP 336 PG 31 WC Political Science SC Government & Law GA BP72X UT WOS:000085992600012 ER PT S AU Deutschmann, J Bar-Itzhack, I Larimore, WE Harman, R AF Deutschmann, J Bar-Itzhack, I Larimore, WE Harman, R BE Culp, RD Weimer, DJ TI Improved modeling in a Matlab-based navigation system SO GUIDANCE AND CONTROL 1999 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 22nd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 03-07, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Sci AB An innovative approach to autonomous navigation is available for low earth orbit satellites. The system is developed in Matlab and utilizes an Extended Kalman Filter (EKF) to estimate the attitude and trajectory based on spacecraft magnetometer and gyro data. Preliminary tests of the system with real spacecraft data from the Rossi X-Ray Timing Explorer Satellite (RXTE) indicate the existence of unmodeled errors in the magnetometer data. Incorporating into the EKF a statistical model that describes the colored component of the effective measurement of the magnetic field vector could improve the accuracy of the trajectory and attitude estimates and also improve the convergence time. This model is identified as a first order Markov process. With the addition of the model, the EKF attempts to estimate the non-white components of the noise allowing for more accurate estimation of the original state vector, i.e. the orbital elements and the attitude. Working in Matlab allows for easy incorporation of new models into the EKF and the resulting navigation system is generic and can easily be applied to future missions resulting in an alternative in onboard or ground-based navigation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Deutschmann, J (reprint author), NASA, Goddard Space Flight Ctr, Code 572, Greenbelt, MD 20771 USA. NR 10 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 0-87703-456-7 J9 ADV ASTRONAUT SCI PY 1999 VL 101 BP 95 EP 103 PG 9 WC Engineering, Aerospace SC Engineering GA BN14B UT WOS:000080857900008 ER PT S AU Scott, S Sabelhaus, P Rapp, J Mazzocco, C Bjork, B Hawkins, K Tralie, J Deshield, M AF Scott, S Sabelhaus, P Rapp, J Mazzocco, C Bjork, B Hawkins, K Tralie, J Deshield, M BE Culp, RD Weimer, DJ TI LANDSAT-7 failure detection and correction SO GUIDANCE AND CONTROL 1999 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 22nd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 03-07, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Sci AB The LANDSAT-7 Satellite maintains continuity with the more than 25 years of Earth remote Sensing data produced by previous LANDSAT missions while providing significant radiometric and geometric performance enhancements. LANDSAT-7's spacecraft bus design is based on the highly successful DMSP/TIROS heritage with enhancements that provide extended duration safe-operation autonomy. This paper describes the systematic approach taken to define, implement, and test the Failure Detection and Correction (FDAC) design features added to the heritage design. The result is a design that is substantially more tolerant to on-orbit failures and more likely to ensure successful recovery from them. LANDSAT-7's Failure Detection and Correction (FDAC) design consists of three major detection elements and a layered array of corrective measures. Detection is rooted in the function called Redundancy Management (REDMN), which continuously monitors selective spacecraft functions and performance, and manages component switching to ensure adequate space vehicle health and safety. LANDSAT-7's design incorporates a second key function called Interconnect Monitor (ICMON) that uses weighted component failure and performance telemetry data to deduce common hardware data path anomalies that otherwise manifest themselves as multiple component failures. ICMON essentially supercedes REDMN by switching to alternate data paths in an attempt to avoid multiple component switching. The third element is an added telemetry function called Status Monitor (SMON), which enhances visibility into all FDAC functions thereby improving ground reconstruction of events leading to an anomaly and facilitating quick recovery to nominal operations. Corrective measures rely on component switching and backup mode switching, including a newly added attitude-safe and energy-safe Sun Painting Attitude Mode. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Scott, S (reprint author), NASA, Goddard Space Flight Ctr, Code 730, Greenbelt, MD 20771 USA. NR 2 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 0-87703-456-7 J9 ADV ASTRONAUT SCI PY 1999 VL 101 BP 181 EP 199 PG 19 WC Engineering, Aerospace SC Engineering GA BN14B UT WOS:000080857900013 ER PT S AU Howard, RT Bryan, TC Book, ML Dabney, RW AF Howard, RT Bryan, TC Book, ML Dabney, RW BE Culp, RD Weimer, DJ TI The Video Guidance Sensor: A flight proven technology SO GUIDANCE AND CONTROL 1999 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 22nd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 03-07, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Sci AB The Video Guidance Sensor (VGS) flew on Shuttle mission STS-95 in October of 1998 to test the VGS functional characteristics on orbit. The flight experiment sensor was designed to operate from 1.5 meter range out to 110 meter range, with a field-of-view of 16 X 21 degrees. This was the second flight of the VGS, and during these two flights, both long range and short range data were gathered under a variety of lighting conditions, orbital exposure times, and temperatures. The VGS tracked its target at a 5 Hz rate and returned 6-degree-of-freedom information on the target's position and attitude relative to the sensor. The VGS was mounted in the Shuttle cargo bay, and its target was mounted on the Spartan spacecraft being carried on this mission. The VGS is a sensor designed to allow an automated vehicle to dock with a spacecraft equipped with a passive target. The VGS is a part of an Automated Rendezvous and Capture (AR&C) system being developed and tested by NASA. The orbital testing included operations with the target on the Shuttle's Remote Manipulator System (RMS) near the start of each flight of the VGS, long-range data (on the STS-95 flight) during the Shuttle rendezvous with the Spartan two days later, and some more RMS operations later in the mission. The data returned from the orbital testing included VGS diagnostics, acquisition, and tracking data, RMS positions, hand-held laser range data, tapes of the data from the VGS video camera, and orbital positioning data from the Spartan and the Shuttle to allow correlation of the VGS data with orbital best-estimate-of-truth data. The Video Guidance Sensor performed well in all phases of the testing, and the VGS is being incorporated into the ground testing of a complete automated rendezvous and docking system. Work on the development of the next generation VGS is continuing. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Howard, RT (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 8 TC 5 Z9 5 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-456-7 J9 ADV ASTRONAUT SCI PY 1999 VL 101 BP 281 EP 298 PG 18 WC Engineering, Aerospace SC Engineering GA BN14B UT WOS:000080857900018 ER PT S AU Ward, DK Andrews, SF McComas, DC O'Donnell, JR AF Ward, DK Andrews, SF McComas, DC O'Donnell, JR BE Culp, RD Weimer, DJ TI Use of the MATRIXx integrated toolkit on the microwave anisotropy probe attitude control system SO GUIDANCE AND CONTROL 1999 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 22nd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 03-07, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Sci AB Recent advances in analytical software tools allow the analysis, simulation, flight code, and documentation of an algorithm to be generated from a single source, all within one integrated analytical design package. NASA's Microwave Anisotropy Probe project has used one such package, Integrated Systems' MATRIXx suite, in the design of the spacecraft's Attitude Control System. The project's experience with the linear analysis, simulation, code generation, and documentation tools will be presented and compared with more traditional development tools. In particular, the quality of the flight software generated will be examined in detail. Finally, lessons learned on each of the tools will be shared. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ward, DK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 3 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 0-87703-456-7 J9 ADV ASTRONAUT SCI PY 1999 VL 101 BP 317 EP 334 PG 18 WC Engineering, Aerospace SC Engineering GA BN14B UT WOS:000080857900020 ER PT S AU Holmes, E Ha, K Hawkins, K Lombardo, J Phillips, R Ram, M Sabelhaus, P Scott, S AF Holmes, E Ha, K Hawkins, K Lombardo, J Phillips, R Ram, M Sabelhaus, P Scott, S BE Culp, RD Weimer, DJ TI Landsat-7 simulation and testing environments SO GUIDANCE AND CONTROL 1999 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 22nd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 03-07, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Sci AB A spacecraft Attitude Control and Determination Subsystem (ACDS) is heavily dependent upon simulation throughout its entire development, implementation and ground test cycle, Engineering simulation tools are typically developed to design and analyze control systems to validate the design and software simulation tools are required to qualify the flight software. However, the need for simulation does not end here. Operating the ACDS of a spacecraft on the ground requires the simulation of spacecraft dynamics, disturbance modeling and celestial body motion. Sensor data must also be simulated and substituted for actual sensor data on the ground so that the spacecraft will respond by sending commands to the actuators as they will on orbit. And finally, the simulator is the primary training tool and test-bed for the Flight Operations Team. In this paper various ACDS simulations developed for or used by the Landsat 7 project will be described. The paper will include a description of each tool, its unique attributes, and its role in the overall development and testing of the ACDS. Finally, a section is included which discusses how the coordinated use of these simulation tools can maximize the probability of uncovering software, hardware and operations errors during the ground test process. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Holmes, E (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 7 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 0-87703-456-7 J9 ADV ASTRONAUT SCI PY 1999 VL 101 BP 335 EP 349 PG 15 WC Engineering, Aerospace SC Engineering GA BN14B UT WOS:000080857900021 ER PT S AU Robertson, B Placanica, S Morgenstern, W AF Robertson, B Placanica, S Morgenstern, W BE Culp, RD Weimer, DJ TI TRMM on-orbit Attitude Control System performance SO GUIDANCE AND CONTROL 1999 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 22nd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 03-07, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Sci AB This paper presents an overview of the Tropical Rainfall Measuring Mission (TRMM) Attitude Control System (ACS) along with detailed inflight performance results for each operational mode. TRMM is a joint mission between NASA and the National Space Development Agency (NASDA) of Japan designed to monitor and study tropical rainfall and the associated release of energy. The TRMM spacecraft is an Earth-pointed, zero momentum bias satellite launched on November 27, 1997 from Tanegashima Space Center, Japan. Launched to provide a validation for poorly known rainfall data sets generated by global climate models, TRMM has demonstrated its utility by reducing uncertainties in global rainfall measurements by a factor of two. The ACS is comprised of Attitude Control Electronics (ACE), an Earth Sensor Assembly (ESA), Digital Sun Sensors (DSS), Inertial Reference Units (IRU), Three Axis Magnetometers (TAM), Coarse Sun Sensors (CSS), Magnetic Torquer Bars (MTB), Reaction Wheel Assemblies (RWA), Engine Valve Drivers (EVD) and thrusters. While in Mission Mode, the ESA provides roll and pitch axis attitude error measurements and the DSS provide yaw updates twice per orbit. In addition, the TAM in combination with the IRU and DSS can be used to provide pointing in a contingency attitude determination mode which does not rely on the ESA. Although the ACS performance to date has been highly successful, lessons were learned during checkout and initial on-orbit operation. This paper describes the design, on-orbit checkout, performance and lessons learned for the TRMM ACS. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Robertson, B (reprint author), NASA, Goddard Space Flight Ctr, Code 571, Greenbelt, MD 20771 USA. NR 3 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 0-87703-456-7 J9 ADV ASTRONAUT SCI PY 1999 VL 101 BP 421 EP 436 PG 16 WC Engineering, Aerospace SC Engineering GA BN14B UT WOS:000080857900027 ER PT S AU Zimbelman, D Watzin, JG AF Zimbelman, D Watzin, JG BE Culp, RD Weimer, DJ TI On-orbit performance of the Transition Region And Coronal Explorer (TRACE) Attitude Control System SO GUIDANCE AND CONTROL 1999 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 22nd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 03-07, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Sci AB This paper presents an overview of the Transition Region And Coronal Explorer (TRACE) Attitude Control System (ACS) along with detailed in-flight performance results for each operational mode. The TRACE spacecraft is the fourth in NASA's Small Explorer (SMEX) series of missions and was successfully launched on April 1, 1998. The primary science objective is to explore the relationship between the fine scale magnetic fields in the solar surface and features in the photosphere, chromosphere, transition region, and corona. TRACE is unique in a sense that an instrument provided guide telescope is used to generate fine pointing error signals for both the ACS and a separate active instrument Image Stabilization System. In addition, the guide telescope provides the mechanism for maneuvering the vehicle to specified targets on the sun. Furthermore TRACE represents the first flight of the Goddard Space Flight Center developed high torque reaction wheel and three-axis gyro pack. Following the ACS description, flight data for each ACS mode will be presented and discussed with respect to the mission level requirements. For example, the ACS is required to point the main science telescope at a specified solar target with an accuracy of 20 are-seconds. Flight data shows that the spacecraft is not only satisfying this requirement but is achieving an attitude pointing accuracy of 0.25 are-seconds (80 times better). Additional data will be shown to highlight the ACS response to events such as the main science telescope door opening and lunar occultation periods. C1 NASA, Goddard Space Flight Ctr, GN&C Syst Engn Branch, Greenbelt, MD 20771 USA. RP Zimbelman, D (reprint author), NASA, Goddard Space Flight Ctr, GN&C Syst Engn Branch, Code 571, Greenbelt, MD 20771 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-456-7 J9 ADV ASTRONAUT SCI PY 1999 VL 101 BP 437 EP 455 PG 19 WC Engineering, Aerospace SC Engineering GA BN14B UT WOS:000080857900028 ER PT S AU McClanahan, TP Mikheeva, I Trombka, JI Floyd, SR Boynton, WV Bailey, H Bhangoo, J Starr, R Clark, PE Evans, LG Squyres, S McCartney, E Noe, E McNutt, R Bruckner, J AF McClanahan, TP Mikheeva, I Trombka, JI Floyd, SR Boynton, WV Bailey, H Bhangoo, J Starr, R Clark, PE Evans, LG Squyres, S McCartney, E Noe, E McNutt, R Bruckner, J BE James, RB Schirato, RC TI Data processing for the Near Earth Asteroid Rendezvous (NEAR), X-ray and Gamma-ray spectrometer (XGRS) ground system SO HARD X-RAY, GAMMA-RAY, AND NEUTRON DETECTOR PHYSICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hard X-Ray, Gamma-Ray, and Neutron Detector Physics CY JUL 19-23, 1999 CL DENVER, CO SP SPIE DE NEAR; XGRS; 433 Eros; X-ray; gamma-ray; asteroid; virtual; visualization; model; data processing AB An X-ray and Gamma-ray spectrometer (XGRS) is onboard the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433Eros. The Eros asteroid is highly nonspherical in physical shape and the development of data management and analysis methodologies are in several areas a divergence from traditional remotely sensed geographical information systems techniques. Field of view and asteroid surface geometry must be derived virtually and then combined with real measurements of solar, spectral and instrument calibration information to derive meaningful scientific results. Spatial resolution of planned geochemical maps will be improved from the initial conditions of low statistical significance per integration by repeated surface flyovers and regional spectral accumulation. This paper describes the results of a collaborative effort of design and development of the NEAR XGRS instrument ground system undertaken by participants at the Goddard Space Flight Center, University of Arizona, Cornell University, Applied Physics Laboratory, and Max Plank institute. C1 NASA, Goddard Space Flight Ctr, Astrchem Branch, Greenbelt, MD 20771 USA. RP McClanahan, TP (reprint author), NASA, Goddard Space Flight Ctr, Astrchem Branch, Greenbelt, MD 20771 USA. RI McNutt, Ralph/E-8006-2010 OI McNutt, Ralph/0000-0002-4722-9166 NR 5 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 0-8194-3254-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3768 BP 74 EP 87 DI 10.1117/12.366572 PG 14 WC Instruments & Instrumentation; Optics; Physics, Multidisciplinary; Physics, Condensed Matter SC Instruments & Instrumentation; Optics; Physics GA BN97V UT WOS:000083737600008 ER PT S AU Parker, BH Stahle, CM Barthelmy, SD Parsons, AM Tueller, J Van Sant, JT Munoz, BF Snodgrass, SJ Mullinix, RE AF Parker, BH Stahle, CM Barthelmy, SD Parsons, AM Tueller, J Van Sant, JT Munoz, BF Snodgrass, SJ Mullinix, RE BE James, RB Schirato, RC TI Correlation between bulk material defects and spectroscopic response in cadmium zinc telluride detectors SO HARD X-RAY, GAMMA-RAY, AND NEUTRON DETECTOR PHYSICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hard X-Ray, Gamma-Ray, and Neutron Detector Physics CY JUL 19-23, 1999 CL DENVER, CO SP SPIE DE CdZnTe; infrared transmission imaging; spectral mapping ID CDZNTE AB One of the critical challenges for large area cadmium zinc telluride (CdZnTe) detector arrays is obtaining material capable of uniform imaging and spectroscopic response. Two complementary nondestructive techniques for characterizing bulk CdZnTe have been developed to identify material with a uniform response. The first technique, infrared transmission imaging, allows for rapid visualization of bulk defects. The second technique, x-ray spectral mapping, provides a map of the material spectroscopic response when it is configured as a planar detector. The two techniques have been used to develop a correlation between bulk defect type and detector performance. The correlation allows for the use of infrared imaging to rapidly develop wafer mining maps. The mining of material free of detrimental defects has the potential to dramatically increase the yield and quality of large area CdZnTe defector arrays. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Parker, BH (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Tueller, Jack/D-5334-2012; Barthelmy, Scott/D-2943-2012; Parsons, Ann/I-6604-2012 NR 10 TC 9 Z9 9 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 0-8194-3254-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3768 BP 129 EP 137 DI 10.1117/12.366576 PG 9 WC Instruments & Instrumentation; Optics; Physics, Multidisciplinary; Physics, Condensed Matter SC Instruments & Instrumentation; Optics; Physics GA BN97V UT WOS:000083737600013 ER PT S AU Barthelmy, SD Cline, TL Butterworth, P Palmer, D Trombka, J McClanahan, T Gold, R Hurley, K AF Barthelmy, SD Cline, TL Butterworth, P Palmer, D Trombka, J McClanahan, T Gold, R Hurley, K BE James, RB Schirato, RC TI Automatic NEAR-XGRS data processing system for rapid and precise GRB localizations with the interplanetary network SO HARD X-RAY, GAMMA-RAY, AND NEUTRON DETECTOR PHYSICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hard X-Ray, Gamma-Ray, and Neutron Detector Physics CY JUL 19-23, 1999 CL DENVER, CO SP SPIE DE Gamma Ray Burst; GRB; automated analysis & distribution ID 28 FEBRUARY 1997; GAMMA-RAY BURST AB The on-board flight software for the Near Earth Asteroid Rendezvous (NEAR) spacecraft was modified to produce continuous 1-sec sampled rate information from the shield of the X-ray and Gamma Ray Spectrometer (XGRS) instrument. Since the XGRS shield can also detect Gamma Ray Bursts (GRB), this rate information can be used in combination with the GRB detections by the Ulysses and near-Earth GRB instruments as part of the Interplanetary Network (IPN) to triangulate the source direction of GRBs. It is the long baseline of NEAR (similar to 1.5 AU) combined with the Ulysses baseline (similar to 5 AU) that makes small error box locations possible. We have developed an automated system to analyze the periodic telemetry dumps from the NEAR spacecraft It extracts this new data type, scans the rate information for increases which are plausibly of GRB origin, and combines these with the GRB detections from the other spacecraft. Because the processing is automated (for all spacecraft), the time delay to produce the triangulated positions is kept to a minimum, up to 48 hours (all but a few minutes of which is due to the inherent delay of the TM dumps). This automated processing and distribution of the GRB locations is done within the GRB Coordinates Network (GCN) system. About 60 localizations per year with errors ranging from a few to tens of arcminutes are expected. These rapid precise localizations may provide about 10 times the rate currently provided by the WFC and NFI instruments on BeppoSAX. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barthelmy, SD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI McClanahan, Timothy/C-8164-2012; Barthelmy, Scott/D-2943-2012 NR 10 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 0-8194-3254-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3768 BP 444 EP 450 DI 10.1117/12.366611 PG 7 WC Instruments & Instrumentation; Optics; Physics, Multidisciplinary; Physics, Condensed Matter SC Instruments & Instrumentation; Optics; Physics GA BN97V UT WOS:000083737600046 ER PT B AU Unwin, S Pitesky, J Shao, M AF Unwin, S Pitesky, J Shao, M BE Egret, D Heck, A TI Science with the Space Interferometry Mission SO HARMONIZING COSMIC DISTANCE SCALES IN A POST-HIPPARCOS ERA SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Colloquium on Harmonizing Cosmic Distance Scales in a Post-Hipparcos Era CY SEP 14-16, 1998 CL HAGUENAU, FRANCE SP Astron Soc Pacific ID GLOBULAR-CLUSTERS AB The Space Interferometry Mission (SIM) will be NASA's first dedicated space-based optical interferometer. SIM will produce a wealth of new astronomical data and serve as a technology pathfinder for future astrophysics missions. It will provide 4 microarcsecond (mu as) precision absolute position measurements of stars down to 20th magnitude, and 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, size, and dynamics of our Galaxy. In this paper we present selected topics from the SIM science program which bear upon determining the extragalactic distance scale. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Unwin, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 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 1-886733-88-0 J9 ASTR SOC P PY 1999 VL 167 BP 38 EP 43 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN45B UT WOS:000081943200004 ER PT B AU Madore, BF Freedman, WL AF Madore, BF Freedman, WL BE Egret, D Heck, A TI Helium core flash and tip of the red giant branch distances SO HARMONIZING COSMIC DISTANCE SCALES IN A POST-HIPPARCOS ERA SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Colloquium on Harmonizing Cosmic Distance Scales in a Post-Hipparcos Era CY SEP 14-16, 1998 CL HAGUENAU, FRANCE SP Astron Soc Pacific ID HUBBLE-SPACE-TELESCOPE; RR LYRAE STARS; DWARF ELLIPTICAL GALAXIES; GLOBULAR-CLUSTER SYSTEM; STELLAR POPULATIONS; RESOLVED GALAXIES; PHOTOMETRY; INDICATOR; NGC-3115; CONSTANT AB Theory suggests and observations confirm that the tip of the first-ascent red giant branch can be used as an accurate and precise distance indicator for all galaxies displaying a measurable population of low-metallicty stars. The bolometric luminosity at which the helium core flash is triggered in low-mass stars is well understood to be largely independent of the mass and/or the chemical composition of the layers surrounding the degenerate He core. The bolometric luminosity at core flash is then expected to be a standard candle of relatively high stellar luminosity and having low dispersion. Empirical evidence suggest that, for a wide range of atmospheric metallicities, the emergent I-band flux shares the low dispersion in luminosity predicted by theory. The early history of using the brightest stars in globular clusters as distance indicators is reviewed and contrasted with the modern, tip of the red giant branch (TRGB) method currently being employed extensively in the determination of extragalactic distances. Recent applications of the TRGB method are also reviewed. Finally, comparisons are made with the Cepheid distance scale, and prospects for future applications are outlined. C1 CALTECH, Jet Prop Lab, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. RP Madore, BF (reprint author), CALTECH, Jet Prop Lab, NASA, IPAC Extragalact Database, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 37 TC 2 Z9 2 U1 1 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-88-0 J9 ASTR SOC P PY 1999 VL 167 BP 161 EP 174 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN45B UT WOS:000081943200015 ER PT S AU Kosovichev, AG Duvall, TL Scherrer, PH AF Kosovichev, AG Duvall, TL Scherrer, PH BE Frohlich, C Foing, BH TI Time-distance helioseismology SO HELIOSEISMOLOGY AND SOLAR VARIABILITY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT Symposium E2 1 of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astron Union, Ctr Natl Etudes Spatiales, European Space Agcy, Sci Comm Solar Terrestrial Phys, Comm Space Res ID INSTRUMENT AB The time-distance helioseismology (or helioseismic tomography) is a new promising method for probing 3-D structures and flows beneath the solar surface, which is potentially important for studying the birth of active regions in the sun's interior and for understanding the relation between the internal dynamics of active regions and chromospheric and coronal activity. In this method, the time for waves to travel along subsurface ray paths is determined from the temporal cross correlation of signals at two separated surface points. By measuring the times for many pairs of points from Dopplergrams covering the visible hemisphere, a tremendous quantity of information about the state of the solar interior is derived. As an example, we present the results for supergranular flows and for an active region which emerged near the center of the solar disk in July 1996, and was studied from SOHO/MDI for nine days, both before and after its emergence at the surface. Initial results show a complicated structure of the emerging region in the interior, and suggest that the emerging flux ropes travel very quickly through the depth range of our observations. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RI Duvall, Thomas/C-9998-2012 NR 12 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 2 BP 163 EP 171 DI 10.1016/S0273-1177(99)00496-2 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN87S UT WOS:000083308300004 ER PT S AU Wilhelm, K Lemaire, P Dammasch, IE Hollandt, J Schuhle, U Curdt, W Kucera, T Hassler, DM Huber, MCE AF Wilhelm, K Lemaire, P Dammasch, IE Hollandt, J Schuhle, U Curdt, W Kucera, T Hassler, DM Huber, MCE BE Frohlich, C Foing, BH TI Solar irradiances of UV and EUV lines during the minimum of the sunspot activity in 1996 SO HELIOSEISMOLOGY AND SOLAR VARIABILITY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT Symposium E2 1 of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astron Union, Ctr Natl Etudes Spatiales, European Space Agcy, Sci Comm Solar Terrestrial Phys, Comm Space Res ID ULTRAVIOLET SPECTROMETER SUMER; RADIOMETRIC CALIBRATION; SOHO AB Full Sun observations in UV and EUV emission lines were performed by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on SOHO (Solar and Heliospheric Observatory) in 1996. The radiometric preflight calibration of SUMER is traceable to a primary radiometric source standard - the electron storage ring BESSY. Based on this calibration and on its inflight refinements, the irradiance values at SOHO have been obtained for the lines HeI (lambda 584.33), O v (lambda 629.74), Ne VIII (lambda 770.41), Sv (lambda 786.47), O IV (lambda 787.72), S VI (lambda lambda 933.39, 944.52), HI Ly epsilon (lambda 937.80), C III (lambda 977.04), N V (lambda 1238.81), Si I (lambda 1256.52), and C IV (lambda 1548.20), and the continuum near 1549 Angstrom. Tn this contribution, we compare our measurements with other recent irradiance determinations and discuss, in particular, the observations in the C IV line. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Inst Astrophys Spatiale, F-91405 Orsay, France. Phys Tech Bundesanstalt, D-10587 Berlin, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SW Res Inst, Boulder, CO 80302 USA. European Space Agcy, Estec, Dept Space Sci, NL-2200 AG Noordwijk, Netherlands. RP Wilhelm, K (reprint author), Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. RI Kucera, Therese/C-9558-2012; Hollandt, Jorg/A-2124-2014 NR 12 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 2 BP 229 EP 232 DI 10.1016/S0273-1177(99)00505-0 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN87S UT WOS:000083308300013 ER PT B AU Ebisawa, K AF Ebisawa, K BE Poutanen, J Svensson, R TI X-ray energy spectra of galactic black hole candidates SO HIGH ENERGY PROCESSES IN ACCRETING BLACK HOLES SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Workshop on High Energy Processes in Accreting Black Holes CY JUN 29-JUL 04, 1998 CL GRAFTAVALLEN, SWEDEN SP Nord Inst Theoret Phys, Copenhagen, Theoret Astrophys Ctr, Copenhagen, Nord Acad Adv Studies, Swedish Nat Sci Res Council, Wennergren Fdn Scientif Res, Anna Greta & Holger Crafoord Fund ID SOURCE GRO J1655-40; DISK CORONA MODELS; CYGNUS X-1; ACCRETION DISK; SUPERLUMINAL SOURCE; DYNAMICAL EVIDENCE; COMPACT OBJECTS; BINARY-SYSTEMS; HIGH STATE; LMC X-3 AB Based on the recent observations with high energy astronomical satellites, X-ray spectral properties which are considered proper to the Galactic black hole candidates are reviewed. Recent high quality observations strongly suggest that in the "soft" spectral state an optically thick accretion disk extends down to similar to three Schwarzschild radius around the black hole, while in the "hard" spectral state inner edge of the optically thick disk recedes much further from the disk. Origins of the ultra-soft component in the soft state and the power-law component in the hard state have been understood, the former as an optically thick disk component and the latter as a thermal Comptonization component. However, origin of the hard-tail component in the soft state, which intriguingly does not show a clear spectral break up to at least several hundred keV, is still controversial. The two Galactic superluminal jet sources GRS1915 + 105 and GRO J1655-40 show unique X-ray observational features, while some of their characteristics are reminiscent of the "ultra-high" state of the other nominal black hole candidates. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ebisawa, K (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 69 TC 8 Z9 8 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-81-3 J9 ASTR SOC P PY 1999 VL 161 BP 39 EP 53 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN27T UT WOS:000081412100003 ER PT S AU Ranawake, UA Dorband, JE AF Ranawake, UA Dorband, JE BE Sloot, P Bubak, M Hoekstra, A Hertzberger, B TI BVIEW: A tool for monitoring distributed systems SO HIGH-PERFORMANCE COMPUTING AND NETWORKING, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference and Exhibition on High-Performance Computing and Networking (HPCN EUROPE 99) CY APR 12-14, 1999 CL AMSTERDAM, NETHERLANDS SP Dutch HPCN Fdn, Dutch Org Sci Res, Univ Amsterdam AB The advent of distributed computer systems with hundreds of processors has created the need for software tools for monitoring their resource usage and system status. In this paper, we describe the design, implementation, and performance of the BVIEW software tool for monitoring distributed systems. Our tool has been tested on a 64 node PC cluster running the Linux operating system. However, it could be easily ported to any Unix based workstation cluster. C1 NASA, Goddard Space Flight Ctr, UMBC, USRA,CESDIS, Greenbelt, MD 20771 USA. RP Ranawake, UA (reprint author), NASA, Goddard Space Flight Ctr, UMBC, USRA,CESDIS, Greenbelt, MD 20771 USA. NR 4 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 3-540-65821-1 J9 LECT NOTES COMPUT SC PY 1999 VL 1593 BP 1167 EP 1170 PG 4 WC Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods SC Computer Science GA BQ39Q UT WOS:000088252100122 ER PT B AU Prasad, D Gary, GA Ambastha, AK AF Prasad, D Gary, GA Ambastha, AK BE Rimmele, TR Balasubramaniam, KS Radick, RR TI Complex H-alpha loop activity in a long duration flare SO HIGH RESOLUTION SOLAR PHYSICS: THEORY, OBSERVATIONS, AND TECHNIQUES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 19th NSO/SP International Workshop on High Resolution Solar Physics - Theory Observations and Techniques CY SEP 28-OCT 02, 1998 CL SUNSPOT, NM SP Natl Solar Observ, Natl Opt Astron Observ, NSF, Div Astron & Atmospher Sci, NASA, Off Space Sci, USAF, Off Sci Res, European Off Aerosp Res & Dev, Asian Off Aerosp Res & Dev, USAF, Res Labs, Space Hazards Branch ID MAGNETIC-FIELD AB A long duration flare was observed int reactive region NOAA 6555 on March 23, 1991 at a location of low magnetic shear. This flare displayed complex H-alpha loop activity during the decay phase. Initially, there were a few long loops orientated at an angle of about 45 degree with the east-west axis followed by the appearence of east-west axis. This configuration was aligned shorter loops. By using different magnetic field models, we have extrapolated the photospheric magnetograms to the chromospheric heights. The magnetic field lines computed by using: the potential field model correspond to most of the observed H-alpha loops. In this paper, we report the analysis of high resolution chromospheric observations of the event and describe a possible senario for the post-flare loop activity. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Prasad, D (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, ES82, Huntsville, AL 35812 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-009-9 J9 ASTR SOC P PY 1999 VL 183 BP 523 EP 530 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN98Q UT WOS:000083761400063 ER PT B AU Gezari, D Livingston, W Varosi, F AF Gezari, D Livingston, W Varosi, F BE Rimmele, TR Balasubramaniam, KS Radick, RR TI Thermal structure in sunspots and dynamic solar infrared granulation imaged at 4.8, 12.4, and 18.1 microns SO HIGH RESOLUTION SOLAR PHYSICS: THEORY, OBSERVATIONS, AND TECHNIQUES SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT 19th NSO/SP International Workshop on High Resolution Solar Physics - Theory Observations and Techniques CY SEP 28-OCT 02, 1998 CL SUNSPOT, NM SP Natl Solar Observ, Natl Opt Astron Observ, NSF, Div Astron & Atmospher Sci, NASA, Off Space Sci, USAF, Off Sci Res, European Off Aerosp Res & Dev, Asian Off Aerosp Res & Dev, USAF, Res Labs, Space Hazards Branch AB We have carried out a program of mid-infrared (4.8, 12.4, and 18.1 mu) imaging of the Sun at the McMath/Pierce Solar Telescope. Observations at these wavelengths provide several unique advantages, including the ability to make direct measurements of the gas temperature at well defined altitudes above the photosphere. Images in this new wavelength band have revealed new structure surrounding sunspots, and changing "infrared granulation" that differs significantly in cell structure and time scale of variation compared to granulation seen in visible light. The infrared also holds the potential for high spatial resolution imaging by minimizing the effects of atmospheric seeing. C1 NASA, Goddard Space Flight Ctr, Infrared Astrophys Branch, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Infrared Astrophys Branch, Code 685, Greenbelt, MD 20771 USA. EM gezari@astrolab.gsfc.nasa.gov; wcl@noao.edu NR 6 TC 9 Z9 9 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-009-9 J9 ASTR SOC P PY 1999 VL 183 BP 559 EP 566 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN98Q UT WOS:000083761400067 ER PT S AU Singh, M AF Singh, M BE Niihara, K Nakano, K Sekino, T Yasuda, E TI Design, fabrication and characterization of high temperature joints in ceramic composites SO HIGH TEMPERATURE CERAMIC MATRIX COMPOSITES III SE KEY ENGINEERING MATERIALS LA English DT Article; Proceedings Paper CT 3rd International Conference on High Tempurature Ceramic Matrix Composites (HT-CMC 3) CY SEP 06-09, 1998 CL OSAKA, JAPAN SP Ceram Soc Japan, Amer Ceram Soc, European Ceram Soc, Fine Ceram Res Assoc DE design; fabrication; testing; joints; ceramics; composites AB Ceramic joining has been recognized as one of the enabling technologies for the successful utilization of ceramic components in a number of demanding, high temperature applications. Various joint design philosophies and design issues have been discussed along with an affordable, robust ceramic joining technology (ARCJoinT). A wide variety of silicon carbide-based composite materials, in different shapes and sizes, have been joined using this technology. This technique is capable of producing joints with tailorable thickness and composition. The room and high temperature mechanical properties and fractography of ceramic joints have been reported. These joints maintain their mechanical strength up to 1200 degrees C in air. This technology is suitable for the joining of large and complex shaped ceramic composite components and with certain modifications, can be applied to repair of ceramic components damaged in service. C1 NASA, Lewis Res Ctr, FDC, NYMA, Cleveland, OH 44135 USA. RP Singh, M (reprint author), NASA, Lewis Res Ctr, FDC, NYMA, MS 106-5, Cleveland, OH 44135 USA. NR 17 TC 34 Z9 35 U1 0 U2 0 PU TRANS TECH PUBLICATIONS PI CLAUSTHAL ZELLERFE PA EINERSBERGER BLICK 28, PO BOX 266, W-3392 CLAUSTHAL ZELLERFE, GERMANY SN 1013-9826 BN 0-87849-818-4 J9 KEY ENG MAT PY 1999 VL 164-1 BP 415 EP 419 PG 5 WC Materials Science, Ceramics; Materials Science, Composites SC Materials Science GA BN11H UT WOS:000080750200093 ER PT B AU Smette, A Claeskens, JF Surdej, J AF Smette, A Claeskens, JF Surdej, J BE Carilli, CL Radford, SJE Menten, KM Langston, GI TI Gravitational lensing by damped Ly-alpha absorbers SO HIGHLY REDSHIFTED RADIO LINES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Highly Redshifted Radio Lines CY OCT 09-11, 1997 CL GREEN BANK, WV ID LUMINOSITY FUNCTION; LYMAN-ALPHA; GALAXIES; QUASARS; REDSHIFT; SYSTEMS AB Spiral galaxies are thought to be the main responsible for the damped Ly-alpha (DLA) systems seen in QSO spectra. They can also act as gravitational lenses, affecting quantities derived in DLA surveys. Assuming that z > 0 spiral galaxies are similar to local ones, we find that, at z similar to 0.5, the number density of DLA systems may be over-estimated by up to 90% and the H I cosmological density (Omega(HI)) by up to 170 % in a survey using bright b(q) similar or equal to 16, z(q) greater than or similar to 2 QSOs and in the absence of important extinction by dust. Applying our model to existing surveys, we find that Omega(HI) is significantly over-estimated only in the z < 1.7 ones (by 34 %). Furthermore, statistical tests indicate that these surveys are indeed affected by gravitational lensing at a 2.3% confidence level. If luminosity functions for flat-spectrum radio-sources and optically selected QSOs are similar in shape and slopes, similar Gling effects should affect surveys for 21cm absorbers using bright, high-z flat-spectrum radio-sources. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smette, A (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 15 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 1-886733-76-7 J9 ASTR SOC P PY 1999 VL 156 BP 146 EP 151 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM90S UT WOS:000080088300020 ER PT S AU Launius, RD AF Launius, RD BE Harris, RA TI The view from Washington SO HISTORY OF THE EUROPEAN SPACE AGENCY SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT International Symposium on the History of the European Space Agency CY NOV 11-13, 1998 CL SCI MUSEUM, LONDON, ENGLAND SP European Space Agcy, Sci Museum, London HO SCI MUSEUM ID COOPERATION C1 NASA, Washington, DC 20546 USA. NR 49 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 92-9092-744-5 J9 ESA SP PUBL PY 1999 VL 436 BP 201 EP 215 PG 15 WC History; History & Philosophy Of Science SC History; History & Philosophy of Science GA BP31D UT WOS:000084659000019 ER PT B AU Whittle, J AF Whittle, J BE Sasse, MA Johnson, C TI Improving functional programming environments SO HUMAN-COMPUTER INTERACTION - INTERACT '99 LA English DT Proceedings Paper CT International Conference on Human-Computer Interaction (INTERACT 99) CY AUG 30-SEP 03, 1999 CL EDINBURGH, SCOTLAND SP Int Federat Informat Processing TC 13 DE functional programming; editors; evaluation AB This paper presents a novel program editor, CYNTHIA, for the functional programming language ML. Motivated by the current lack of good programming environments for functional programming, CYNTHIA incorporates programming by analogy, whereby users write programs by applying abstract transformations to existing programs, and sophisticated correctness-checking techniques such as checking for semantic errors, e.g. non-termination. CYNTHIA has been used in two introductory courses in ML and the results of these evaluations are presented here. It was found that students using CYNTHIA committed fewer errors than students using a compiler/text editor approach. In addition, errors that were made could be corrected more easily. C1 NASA, Ames Res Ctr, Recom Technol, Mt View, CA 94040 USA. RP Whittle, J (reprint author), NASA, Ames Res Ctr, Recom Technol, M-S 269-2, Mt View, CA 94040 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU I O S PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS BN 0-9673355-0-7 PY 1999 BP 497 EP 503 PG 3 WC Computer Science, Cybernetics; Computer Science, Information Systems SC Computer Science GA BP26E UT WOS:000084509200061 ER PT S AU Barth, E Beard, BL Ahumada, AJ AF Barth, E Beard, BL Ahumada, AJ BE Rogowitz, BE Pappas, TN TI Nonlinear features in vernier acuity SO HUMAN VISION AND ELECTRONIC IMAGING IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging IV CY JAN 25-28, 1999 CL SAN JOSE, CA SP SPIE, Soc Imaging Sci & Technol DE spatial vision; nonlinear operators; pattern recognition; vernier acuity; visual noise; position uncertainty; nonlinear system identification AB Nonlinear contributions to pattern classification by humans an analyzed by using previously obtained data on discrimination between aligned lines and offset lines. We show that the optimal linear model (which had been identified by correlating the noise added to the presented patterns with the observer's response) can be rejected even when the parameters of the model are estimated individually for each observer. We use a new measure of agreement to reject the linear model and to test simple nonlinear operators. The first nonlinearity is position uncertainty. The linear kernels are shrunk to different extents and convolved with the input images. A Gaussian window weights the results of the convolutions and the maximum in that window is selected as the internal variable. The size of the window is chosen such as to maintain a constant total amount of spatial filtering, i.e. the smaller kernels have a larger position uncertainty. The results of two observers indicate that the best agreement is obtained at a moderate degree of position uncertainty, similar to plus-minus one min of are. Finally, we analyze the effect of orientation uncertainty and show that agreement can be further improved in some cases. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Barth, E (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 8 TC 14 Z9 14 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 0-8194-3115-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3644 BP 88 EP 96 DI 10.1117/12.348485 PG 9 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Computer Science, Information Systems; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BN20A UT WOS:000081058100007 ER PT S AU Watson, AB Hu, J McGowan, JF Mulligan, JB AF Watson, AB Hu, J McGowan, JF Mulligan, JB BE Rogowitz, BE Pappas, TN TI Design and performance of a digital video quality metric SO HUMAN VISION AND ELECTRONIC IMAGING IV SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging IV CY JAN 25-28, 1999 CL SAN JOSE, CA SP SPIE, Soc Imaging Sci & Technol AB The growth of digital video has given rise to a need for computational methods for evaluating the visual quality of digital video. We have developed a new digital video quality metric, which we call DVQ (Digital Video Quality)(1). Here we provide a brief description of the metric, and give a preliminary report on its performance. DVQ accepts a pair of digital video sequences, and computes a measure of the magnitude of the visible difference between them. The metric is based on the Discrete Cosine Transform. It incorporates aspects of early visual processing, including light adaptation, luminance and chromatic channels, spatial and temporal filtering, spatial frequency channels, contrast masking, and probability summation. It also includes primitive dynamics of light adaptation and contrast masking. We have applied the metric to digital video sequences corrupted by various typical compression artifacts, and compared the results to quality ratings made by human observers. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Watson, AB (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 11 TC 30 Z9 30 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 0-8194-3115-X J9 PROC SPIE PY 1999 VL 3644 BP 168 EP 174 DI 10.1117/12.348437 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Computer Science, Information Systems; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BN20A UT WOS:000081058100014 ER PT S AU Blackmon, TT Nguyen, L Neveu, C Rasmussen, D Zbinden, E Maimone, M Matthies, L Thayer, S Teza, J Broz, V Osborn, J Hebert, M Steele, J Thomas, G AF Blackmon, TT Nguyen, L Neveu, C Rasmussen, D Zbinden, E Maimone, M Matthies, L Thayer, S Teza, J Broz, V Osborn, J Hebert, M Steele, J Thomas, G BE Rogowitz, BE Pappas, TN TI Virtual reality mapping system for Chornobyl accident site assessment SO HUMAN VISION AND ELECTRONIC IMAGING IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging IV CY JAN 25-28, 1999 CL SAN JOSE, CA SP SPIE, Soc Imaging Sci & Technol DE Chornobyl; telerobotics; stereo vision; 3d surface reconstruction; virtual reality AB Initiated by the Department of Energy's International Nuclear Safety Program, an effort is underway to deliver and deploy a telerobotic diagnostic system for structural evaluation and monitoring within the Chornobyl Unit-4 shelter. A mobile robot, named Pioneer, will enter the damaged Chornobyl structure and deploy devices to measure radiation, temperature and humidity; acquire core samples of concrete structures for subsequent engineering analysis; and make photo-realistic three-dimensional (3D) maps of the building interior. This paper details the latter element, dubbed 'C-Map', the Chornobyl Mapping System. C-Map consists of an automated 3D modeling system using stereo computer vision along with an interactive, virtual reality (VR) software program to acquire and analyze the photo-realistic 3D maps of the damaged building interior. C1 NASA, Ames Res Ctr MS 269 3, Intelligent Mechaisms Grp, Moffett Field, CA 94035 USA. RP Blackmon, TT (reprint author), NASA, Ames Res Ctr MS 269 3, Intelligent Mechaisms Grp, Moffett Field, CA 94035 USA. NR 9 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 0-8194-3115-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3644 BP 338 EP 345 DI 10.1117/12.348454 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Computer Science, Information Systems; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BN20A UT WOS:000081058100031 ER PT B AU Heap, SR Lanz, TM Brown, T Hubeny, I AF Heap, SR Lanz, TM Brown, T Hubeny, I BE Bunker, AJ VanBreugel, WJM TI Mid-UV spectroscopic dating of LBDS 53W091 SO HY-REDSHIFT UNIVERSE: GALAXY FORMATION AND EVOLUTION AT HIGH REDSHIFT SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Meeting on the Hy-Redshift Universe - Galaxy Formation and Evolution at High Redshift CY JUN 21-24, 1999 CL UNIV CALIF, BERKELEY, CA SP Univ Calif HO UNIV CALIF AB We have calibrated age-related spectral diagnostics in the mid-UV in terms of age and metallicity. We then make a preliminary application to dating the red galaxy, LBDS 53W091 at z = 1.55. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Heap, SR (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI heap, sara/E-2237-2012 NR 7 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 1-58381-019-6 J9 ASTR SOC P PY 1999 VL 193 BP 167 EP 170 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85L UT WOS:000086435200023 ER PT B AU Mushotzky, R AF Mushotzky, R BE Bunker, AJ VanBreugel, WJM TI X-ray observations of groups and clusters - A relic of the high redshift universe SO HY-REDSHIFT UNIVERSE: GALAXY FORMATION AND EVOLUTION AT HIGH REDSHIFT SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Meeting on the Hy-Redshift Universe - Galaxy Formation and Evolution at High Redshift CY JUN 21-24, 1999 CL UNIV CALIF, BERKELEY, CA SP Univ Calif HO UNIV CALIF ID INTRACLUSTER MEDIUM; RICH CLUSTERS; POOR GROUPS; GALAXIES; EVOLUTION; ABUNDANCES; ENRICHMENT; ASCA AB I review the evidence from clusters and groups of galaxies for 'relic' evidence of the high redshift universe. Contrary to the received wisdom, clusters are old. Their x-ray emitting intergalactic medium in massive clusters is a reservoir of metal and energy injection from the main epoch of star formation. There are strong indications that nongravitational energy was extremely important in the formation of low-mass clusters and groups, implying that gravity did not dominate the process on all scales below that of massive, rich clusters. The data indicate that most of the metals in the universe are not in stars but in the hot gas and thus the use of stars to trace metal formation and evolution misses most of the processed material. The group data shows that galaxies are very poor tracers of mass on the scale of 10(13) M. and since groups are the 'average' place in the universe this probably holds for most of the visible universe. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mushotzky, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 48 TC 7 Z9 7 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-019-6 J9 ASTR SOC P PY 1999 VL 193 BP 323 EP 335 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85L UT WOS:000086435200046 ER PT B AU Dwek, E AF Dwek, E BE Bunker, AJ VanBreugel, WJM TI The extragalactic background light: Detections and limits and their cosmological implications SO HY-REDSHIFT UNIVERSE: GALAXY FORMATION AND EVOLUTION AT HIGH REDSHIFT SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT International Meeting on the Hy-Redshift Universe - Galaxy Formation and Evolution at High Redshift CY JUN 21-24, 1999 CL UNIV CALIF, BERKELEY, CA SP Univ Calif HO UNIV CALIF ID STAR-FORMATION HISTORY; HUBBLE DEEP FIELD; GALAXIES; RADIATION; SPECTRUM AB The extragalactic background light (EBL) provides important constraints on models for the origin of galaxies, stars, metals, and dust in the universe. It is also a source of opacity for ultrahigh energy cosmic ray nuclei and photons. This contribution reviews the current observational status of the EEL in the 0.1 to 1000 mu m wavelength regime, and examines its cosmological implications. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. EM eli.dwek@gsfc.nasa.gov NR 43 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 1-58381-019-6 J9 ASTR SOC P PY 1999 VL 193 BP 498 EP 508 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85L UT WOS:000086435200066 ER PT B AU Eisenhardt, P AF Eisenhardt, P BE Bunker, AJ VanBreugel, WJM TI Future observations with SIRTF and other mid-infrared/sub-mm missions SO HY-REDSHIFT UNIVERSE: GALAXY FORMATION AND EVOLUTION AT HIGH REDSHIFT SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Meeting on the Hy-Redshift Universe - Galaxy Formation and Evolution at High Redshift CY JUN 21-24, 1999 CL UNIV CALIF, BERKELEY, CA SP Univ Calif HO UNIV CALIF ID TELESCOPE-FACILITY SIRTF; HIGH-REDSHIFT GALAXIES; STAR-FORMING GALAXIES; HUBBLE DEEP FIELD AB Infrared observations are crucial for studies of high redshift galaxies. I summarize the capabilities of three future infrared space observatories, and give a few examples of applications to the study of galaxy formation and evolution. SIRTF, with its 85 cm, 5.5 K telescope, will be launched in December 2001, providing natural background limited imaging from 3 - 180 mu m and spectroscopy from 5 - 40 mu m over its expected 5 year lifetime. The Next Generation Sky Survey was a proposed (but not selected) Medium Explorer surveying the entire sky at 3.5, 4.7, 12 and 23 mu m with a thousand to a million times better sensitivity than previous all-sky infrared surveys. The larger (3.5 m) but warmer (70 K) Far Infrared and Sub-mm Telescope. is planned for launch in 2007, providing imaging and spectroscopy from 80 - 670 mu m over its 3 year lifetime. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Eisenhardt, P (reprint author), CALTECH, Jet Prop Lab, MS 169-327,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 28 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 1-58381-019-6 J9 ASTR SOC P PY 1999 VL 193 BP 639 EP 650 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85L UT WOS:000086435200085 ER PT B AU Mushotzky, R AF Mushotzky, R BE Bunker, AJ VanBreugel, WJM TI The future Hy-redshift universe - A Hy-E perspective SO HY-REDSHIFT UNIVERSE: GALAXY FORMATION AND EVOLUTION AT HIGH REDSHIFT SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Meeting on the Hy-Redshift Universe - Galaxy Formation and Evolution at High Redshift CY JUN 21-24, 1999 CL UNIV CALIF, BERKELEY, CA SP Univ Calif HO UNIV CALIF ID ROSAT DEEP SURVEY; X-RAY SOURCES; GALAXY FORMATION; LOCKMAN FIELD; BLACK-HOLES AB Deep imaging x-ray observations are probably the best way of detecting high-redshift active galaxies which are, presumably, embedded in high-redshift galaxies. We review the present x-ray data on faint sources and the capabilities of Chandra and XMM for the high-redshift universe. We briefly discuss the exciting possibility of directly detecting the formation of galaxies by observing the cooling of gas in potential wells. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mushotzky, R (reprint author), Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 29 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 1-58381-019-6 J9 ASTR SOC P PY 1999 VL 193 BP 651 EP 661 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85L UT WOS:000086435200086 ER PT J AU Friedson, AJ AF Friedson, AJ TI New observations and modelling of a QBO-like oscillation in Jupiter's stratosphere SO ICARUS LA English DT Article ID QUASI-BIENNIAL OSCILLATION; GENERAL-CIRCULATION MODEL; GRAVITY-WAVES; EQUATORIAL STRATOSPHERE; COMET SHOEMAKER-LEVY-9; INFRARED OBSERVATIONS; SPATIAL-ORGANIZATION; LATITUDINAL SHEAR; UPPER TROPOSPHERE; PLANETARY-WAVES AB We present a new analysis of the "quasi-quadrennial'' oscillation (QQO), a quasi-periodic oscillation of longitude-mean temperatures and winds occurring at low latitudes in Jupiter's stratosphere that may be a phenomenon closely related to Earth's quasi-biennial oscillation (Leovy et al. 1991, Nature 354, 380-382). Measurements of 7.8-mu m thermal emission from the jovian stratosphere acquired during the period 1991-1995 extend observations of this oscillation for an additional cycle beyond those presented in Orton ef al. (1991, Science 252, 537-542), showing that this similar to 4-yr-period signal has persisted for at least 15 yr. Numerical simulations of the QQO are performed to compare the brightness temperature patterns obtained to the groundbased measurements. By coupling these simulations with a radiative transfer model, we find that the amplitude of the oscillation must be significantly larger than previously estimated by Leovy et al. (1991.). Long-period, large-scale equatorial waves on Jupiter are found to be ineffective in driving a QQO that produces the observed amplitude of the brightness temperature oscillations. Simulations in which the wave driving occurs through the interaction of small-scale, short-period gravity waves with their critical levels produce a QQO whose associated brightness temperature variations are in much better agreement with the observations. The amplitude of the QQO predicted by these simulations is large, suggesting that it may have a very significant effect on Jupiter's stratospheric thermal structure at ion: latitudes, some of which may be apparent in the vertical temperature profiles measured by the Galileo Atmospheric Structure Instrument and by the Voyager 1 radio occultation experiment. (C) 1999 Academic Press. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP Friedson, AJ (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, MS 169-237, Pasadena, CA 91109 USA. EM Andrew.J.Friedson@jpl.nasa.gov NR 47 TC 32 Z9 32 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD JAN PY 1999 VL 137 IS 1 BP 34 EP 55 DI 10.1006/icar.1998.6038 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162XT UT WOS:000078373100004 ER PT J AU McKay, CP Lorenz, RD Lunine, JI AF McKay, CP Lorenz, RD Lunine, JI TI Analytic solutions for the antigreenhouse effect: Titan and the early Earth SO ICARUS LA English DT Article DE Titan; atmosphere; greenhouse effect; antigreenhouse effect ID OPTICAL-PROPERTIES; ATMOSPHERE; TROPOSPHERE; REANALYSIS; GREENHOUSE; METHANE; OCEAN; SUN AB The antigreenhouse effect results from a high altitude haze which blocks sunlight while allowing transmission of thermal infrared. An antigreenhouse is observed on Titan and has been proposed for the early Earth. Here, ne derive an analytic solution useful for computing the atmospheric and surface temperature with both the greenhouse and antigreenhouse effects included. In agreement with detailed calculations, the analytic solution predicts that a runaway greenhouse on early Titan caused by accretional heat would collapse when the flux fell to 0.9 W m(-2). For the present value of the solar luminosity a runaway greenhouse collapses at a geothermal heat flux of 0.4 W m(-2). We show that the antigreenhouse effect may compromise attempts to solve the faint young sun problem on the early Earth with a methane-ammonia greenhouse shielded by an organic haze, more than doubling the infrared opacity needed to warm the early Earth compared to the case with no antigreenhouse, (C) 1999 Academic Press. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RI Lorenz, Ralph/B-8759-2016 OI Lorenz, Ralph/0000-0001-8528-4644 NR 18 TC 33 Z9 34 U1 0 U2 9 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 1999 VL 137 IS 1 BP 56 EP 61 DI 10.1006/icar.1998.6039 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162XT UT WOS:000078373100005 ER PT J AU Brandt, JC Caputo, FM Hoeksema, JT Niedner, MB Yi, Y Snow, M AF Brandt, JC Caputo, FM Hoeksema, JT Niedner, MB Yi, Y Snow, M TI Disconnection events (DEs) in Halley's comet 1985-1986. The correlation with crossings of the heliospheric current sheet (HCS) SO ICARUS LA English DT Article ID PLASMA-TAIL ACTIVITY; SECTOR BOUNDARIES; SOLAR-WIND; P/HALLEY; DYNAMICS AB Disconnection events (DEs) from Halley's comet are analyzed as a group tin order to minimize the impact of uncertainties in any single event) for correlation with solar-wind features. This analysis utilizes new coronal source-surface model results and new fitting techniques to determine the best calculated heliospheric current sheet (HCS) location. Details for several DEs are presented. The results confirm that the 19 DEs are associated with crossings of the HCS. No other property of the solar wind shows a one-to-one association with DEs. Thus, theoretical efforts should concentrate on conditions at BCS crossings (see Y, Yi et at, 1996, J. Geophys. Res, 101,27,586-27,601). (C) 1999 Academic Press. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Stanford Univ, Wilcox Solar Observ, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Brandt, JC (reprint author), Univ Colorado, Atmospher & Space Phys Lab, Campus Box 392, Boulder, CO 80309 USA. RI Niedner, Malcolm/E-2244-2012 NR 35 TC 21 Z9 21 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 1999 VL 137 IS 1 BP 69 EP 83 DI 10.1006/icar.1998.6030 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162XT UT WOS:000078373100007 ER PT J AU Ostro, SJ Hudson, RS Rosema, KD Giorgini, JD Jurgens, RF Yeomans, DK Chodas, PW Winkler, R Rose, R Choate, D Cormier, RA Kelley, D Littlefair, R Benner, LAM Thomas, ML Slade, MA AF Ostro, SJ Hudson, RS Rosema, KD Giorgini, JD Jurgens, RF Yeomans, DK Chodas, PW Winkler, R Rose, R Choate, D Cormier, RA Kelley, D Littlefair, R Benner, LAM Thomas, ML Slade, MA TI Asteroid 4179 Toutatis: 1996 radar observations SO ICARUS LA English DT Article DE asteroids; radar; Toutatis ID PHYSICAL-PROPERTIES; 4179-TOUTATIS; SCATTERING; IMAGES; MARS; PLANETS; COMETS; VENUS AB We report initial results of daily delay/Doppler observations of Toutatis with the Goldstone 8510-MHz (3.5-cm) radar during Nov. 25-Dec. 3, 1996. Using the physical model of Toutatis derived from 1992 radar observations (Hudson and Ostro 1995, Science 270, 84-86) to analyze the new data, we obtain refined estimates of the asteroid's orbit, spin state, and surface properties. The asteroid's centimeter-to-decameter surface characteristics are strikingly uniform. The disc-integrated circular polarization (SC/OC) ratio mu(c) averages 0.29 +/- 0.01 and is independent of rotational orientation at the several percent level. Dual-polarization images reveal a slight drop in mu(c) at echo leading edges, which we interpret as the signature of a smooth surface component. The OC radar albedo averages 0.24 +/- 0.03; it depends on rotational orientation, as expected from the asteroid's angular scattering behavior (limb-darkening slightly more than Lambertian). The OC albedo of a sphere with Toutatis' radar properties would be 0.21, or three times the lunar value. The radar properties and available nonradar constraints are consistent with Toutatis' surface having a smooth component that is at least 1/3 covered by rocks at least as large as the wavelength. if this S-class asteroid is mineralogically similar to stony-iron meteorites, then the smooth surface component probably is regolith whose porosity resembles that of lunar soil. if the mineralogy is ordinary chondritic, then the smooth surface component is probably solid with not much more than a centimeter of overlying regolith. We report delay-Doppler astrometry referenced to the asteroid's center of mass (COM) for each day of our experiment. An orbit solution that incorporates those measurements as well as the radar astrometry reported by Ostro et al. (1995, Science 270, 80-83) and 588 optical astrometric observations from 1988 through March 1997 has weighted rms residuals of 0.98 arcs, 0.10 Hz (1.8 mm s(-1) in radial velocity), and 0.49 mu s in time delay (73 m in range). integration of that orbit into the past and future shows that Toutatis' pattern of close approaches to Venus, Earth, and Mars is highly asymmetric about the current epoch. The probability of the orbit intersecting Earth is zero for at least the next six centuries. Toutatis will make its closest planetary approach since at least 1353 and until at least 2562 on Sep. 29, 2004, when the closest COM-to-COM separation of Earth and Toutatis will be 1,549,834 +/- 10 km (4.0 lunar distances). We use refined spin-state parameters and the 1995 shape model to generate "movies" that predict the asteroid's rotational motion during its 2004 close approach, in geocentric and inertial frames. (C) 1999 Academic Press. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Washington State Univ, Sch Elect Engn & Comp Sci, Pullman, WA 99164 USA. RP Ostro, SJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ostro@echo.jpl.nasa.gov NR 69 TC 47 Z9 49 U1 2 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 1999 VL 137 IS 1 BP 122 EP 139 DI 10.1006/icar.1998.6031 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162XT UT WOS:000078373100009 ER PT B AU Wernet, MP AF Wernet, MP GP IEEE IEEE IEEE TI Fuzzy logic enhanced digital PIV processing software SO ICIASF'99: INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 18th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF'99) CY JUN 14-17, 1999 CL TOULOUSE, FRANCE SP Onera-Ctr, Inst Elect & Electr Engineers, European Off Aerosp Res & Dev, Delegat Gen Armement, Conseil Reg Midi-Pyrenees, Mairie Toulouse, Co Presenting Instrument Syst ID VELOCIMETRY AB Digital Particle image Velocimetry (DPIV) is an instantaneous, planar velocity measurement technique that is ideally suited for studying transient flow phenomena in high speed turbomachinery. DPIV is being actively used at the NASA Glenn Research Center to study both stable and unstable operating conditions in a high speed centrifugal compressor. Commercial PIV systems are readily available which provide near real rime feedback of the PN image data quality. These commercial systems are well designed to facilitate the expedient acquisition of PIV image data. However, as with any general purpose system, these commercial PIV systems do not meet all of the data processing needs required for PIV image data reduction in our compressor research program. An in-house PIV PROCessing (PIVPROC) code has been developed for reducing PIV data The PIVPROC software incorporates fuzzy logic data validation for maximum information recovery from PIV image data. PIVPROC enables combined cross-correlation/particle tracking wherein the highest possible spatial resolution velocity measurements are obtained. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Wernet, MP (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5716-7 PY 1999 BP 21 EP 210 DI 10.1109/ICIASF.1999.827141 PG 190 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BQ47C UT WOS:000088436500002 ER PT B AU Shams, QA Zuckerwar, AJ AF Shams, QA Zuckerwar, AJ GP IEEE IEEE IEEE TI Electronically scanned pressure measurement scanner for cryogenic wind tunnel applications SO ICIASF'99: INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 18th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF'99) CY JUN 14-17, 1999 CL TOULOUSE, FRANCE SP Onera-Ctr, Inst Elect & Electr Engineers, European Off Aerosp Res & Dev, Delegat Gen Armement, Conseil Reg Midi-Pyrenees, Mairie Toulouse, Co Presenting Instrument Syst AB Electronically scanned pressure (ESP) measurement modules are used in Rind tunnels to measure surface pressures on models. Measurement channels are connected to pressure ports through small diameter tubing. Use of current state-of-the art ESP scanners in cryogenic wind tunnels has led to several practical problems which contribute to additional expense and loss of data quality. First current use of ESP scanners in cryogenic wind tunnels (at room temperature below 25 C) dictates the need for protection against the thermal environment. nle current solution is the use of a heater box which causes a number of operational problems. The installation of the hearer bos is time-consuming and labor-intensive. Its size reduces the amount of space available for scanner installation. Secondly, a wind tunnel test must be interrupted for on-line calibration which consumes as much as 15% of the total test time. Finally, the pressure and balance measurements are taken in separate runs because of an "apparent strain" problem. An electronically scanned pressure measurement module capable of operating directly in a cryogenic environment has been developed and tested over an extended temperature span Total uncertainty, which is measured at less than 0.1% of FSO at 1 atmospheric reference pressure will be discussed. C1 NASA, Langley Res Ctr, NYMA Inc, Hampton, VA 23681 USA. RP Shams, QA (reprint author), NASA, Langley Res Ctr, NYMA Inc, MS 236, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5716-7 PY 1999 BP 361 EP 366 DI 10.1109/ICIASF.1999.827176 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BQ47C UT WOS:000088436500036 ER PT B AU Seasholtz, R Panda, J AF Seasholtz, R Panda, J GP IEEE IEEE IEEE TI Multiple point dynamic gas density measurements using molecular Rayleigh scattering SO ICIASF'99: INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 18th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF'99) CY JUN 14-17, 1999 CL TOULOUSE, FRANCE SP Onera-Ctr, Inst Elect & Electr Engineers, European Off Aerosp Res & Dev, Delegat Gen Armement, Conseil Reg Midi-Pyrenees, Mairie Toulouse, Co Presenting Instrument Syst AB A nonintrusive technique for measuring dynamic gas density properties is described. Molecular Rayleigh scattering is used to measure the time-history of gas density simultaneously at eight spatial locations at a 50 kHz sampling rate. The data are analyzed using the Welch method of modified periodograms to reduce measurement uncertainty. Cross-correlations, power spectral density functions, cross-spectral density functions, and coherence functions may be obtained from the data. The technique is demonstrated using low speed co-flowing jets with a heated inner jet. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Seasholtz, R (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5716-7 PY 1999 BP 431 EP 4310 DI 10.1109/ICIASF.1999.827183 PG 3880 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BQ47C UT WOS:000088436500043 ER PT B AU Laubach, SL Burdick, JW AF Laubach, SL Burdick, JW GP IEEE IEEE TI An autonomous sensor-based path-planner for planetary microrovers SO ICRA '99: IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Robotics and Automation (ICRA '99) CY MAY 10-15, 1999 CL DETROIT, MI SP IEEE, Robot & Automat Soc AB With the success of Mars Pathfinder's Sojourner rover, a new era of planetary exploration has opened, with demand for highly capable mobile robots. These robots must be able to traverse long distances over rough, unknown terrain autonomously, under severe resource constraints. Based on the authors' firsthand experience with the Mars Pathfinder mission, this paper reviews issues which are critical for successful autonomous navigation of planetary revers. We next report on the "Wedgebug" algorithm for planetary rover navigation. This algorithm is complete, correct, requires minimal memory for storage of its world model, and uses only on-board sensors, which are guided by the algorithm to efficiently sense only the data needed for motion planning. The implementation of a version of Wedgebug on the Rocky7 Mars Rover prototype at the Jet Propulsion Laboratory (JPL) is described, and experimental results from operation in simulated martian terrain are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Laubach, SL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 15 Z9 18 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5181-9 PY 1999 BP 347 EP 354 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BN32H UT WOS:000081625700058 ER PT B AU Lovchik, CS Diftler, MA AF Lovchik, CS Diftler, MA GP IEEE IEEE TI The Robonaut Hand: A dexterous robot hand for space SO ICRA '99: IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Robotics and Automation (ICRA '99) CY MAY 10-15, 1999 CL DETROIT, MI SP IEEE, Robot & Automat Soc AB A highly anthropomorphic human scale robot hand designed for space based operations is presented. This five finger hand combined with its integrated wrist and forearm has fourteen independent degrees of freedom. The device approximates very well the kinematics and required strength of an astronaut's hand when operating through a pressurized space suit glove. The mechanisms used to meet these requirements are described in detail along with the design philosophy behind them. Integration experiences reveal the challenges associated with obtaining the required capabilities within the desired size. C1 NASA, Johnson Space Ctr, Robot Technol Branch, Houston, TX 77058 USA. RP NASA, Johnson Space Ctr, Robot Technol Branch, Houston, TX 77058 USA. EM lovchik@jsc.nasa.gov; diftler@jsc.nasa.gov NR 16 TC 187 Z9 215 U1 4 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5180-0; 0-7803-5181-9 PY 1999 BP 907 EP 912 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BN32H UT WOS:000081625700144 ER PT B AU Backes, PG Rabideau, G Tso, KS Chien, S AF Backes, PG Rabideau, G Tso, KS Chien, S GP IEEE IEEE TI Automated planning and scheduling for planetary rover distributed operations SO ICRA '99: IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Robotics and Automation (ICRA '99) CY MAY 10-15, 1999 CL DETROIT, MI SP IEEE, Robot & Automat Soc ID MARS AB Automated planning and scheduling, including automated path planning, has been integrated with an Internet-based distributed operations system for planetary rover operations. The resulting prototype system enables faster generation of valid rover command sequences by a distributed planetary rover operations team. The Web Interface for Telescience (WITS) provides Internet-based distributed collaboration, the Automated Scheduling and Planning ENvironment (ASPEN) provides automated planning and scheduling, and an automated path planner provides path planning. The system was demonstrated on the Rocky7 research rover at JPL. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 4 Z9 5 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5180-0; 0-7803-5181-9 PY 1999 BP 984 EP 991 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BN32H UT WOS:000081625700156 ER PT B AU Estlin, T Fisher, F Mutz, D Chien, S AF Estlin, T Fisher, F Mutz, D Chien, S GP IEEE IEEE TI Automated planning for a Deep Space Communications Station SO ICRA '99: IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Robotics and Automation (ICRA '99) CY MAY 10-15, 1999 CL DETROIT, MI SP IEEE, Robot & Automat Soc AB This paper describes the application of Artificial Intelligence planning techniques to the problem of antenna track plan generation for a NASA Deep Space Communications Station. The described system Enables an antenna communications station to automatically respond to a set of tracking goals by correctly configuring the appropriate hardware and software to provide the requested communication services. To perform this task, the Automated Scheduling and Planning Environment (ASPEN) has been applied to automatically produce antenna tracking plans that are tailored to support a set of input goals. In this paper, we describe the antenna automation problem, the ASPEN planning and scheduling system, how ASPEN is used to generate antenna track plans, the results of several technology demonstrations, and future work utilizing dynamic planning technology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Estlin, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5181-9 PY 1999 BP 1410 EP 1417 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BN32H UT WOS:000081625700223 ER PT B AU Olson, CF AF Olson, CF GP IEEE IEEE TI Subpixel localization and uncertainty estimation using occupancy grids SO ICRA '99: IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Robotics and Automation (ICRA '99) CY MAY 10-15, 1999 CL DETROIT, MI SP IEEE, Robot & Automat Soc AB We describe techniques for performing mobile robot localization using occupancy grids that allow subpixel localization and uncertainty estimation in the pixelized pose space. The techniques are based on a localization method where matching is performed between the visible landmarks at the current robot position and a previously generated map of the environment. A likelihood function over the space of possible robot positions is formulated as a function of the probability distribution for the map matching error. Subpixel localization and uncertainty estimation are performed by fitting the likelihood function with a parameterized surface. The performance of the method is analyzed using synthetic experiments and an example is given using the Rocky 7 Mars rover prototype. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 125-209, Pasadena, CA 91109 USA. NR 8 TC 10 Z9 10 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5180-0; 0-7803-5181-9 PY 1999 BP 1987 EP 1992 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BN32H UT WOS:000081625700314 ER PT B AU Seraji, H AF Seraji, H GP IEEE IEEE TI Traversability index: A new concept for planetary rovers SO ICRA '99: IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Robotics and Automation (ICRA '99) CY MAY 10-15, 1999 CL DETROIT, MI SP IEEE, Robot & Automat Soc AB Traversability Index is introduced in this paper as a new and simple measure for traversability of planetary surfaces by mobile robots. This index is developed using the framework of fuzzy logic, and is expressed by linguistic fuzzy sets that quantify the suitability of the terrain for traversal based on its physical properties, such as slope and roughness. The Traversability Index is used for classifying planetary surfaces, and provides a simple means for incorporating the terrain quality data (out to about 10 meters) into the rover navigation strategy. A set of fuzzy navigation rules is developed using the Traversability Index to guide the rover toward the safest and the most traversable terrain. In addition, another set of fuzzy rules is developed to drive the rover from its initial position to a user-specified goal position. These two rule sets are integrated in a two-stage procedure for autonomous rover navigation without a prior knowledge about the environment. A computer simulation study is presented to demonstrate the capability of the rover to reach the goal safely while avoiding impassable terrains. 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 12 TC 15 Z9 17 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5181-9 PY 1999 BP 2006 EP 2013 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BN32H UT WOS:000081625700317 ER PT S AU Hughes, JS McMahon, SK AF Hughes, JS McMahon, SK GP IEEE COMP SOC IEEE COMP SOC TI The Planetary Data System - Distributed Inventory System SO IEEE FORUM ON RESEARCH AND TECHNOLOGY ADVANCES IN DIGITAL LIBRARIES, PROCEEDINGS SE PROCEEDINGS - IEEE INTERNATIONAL FORUM ON RESEARCH AND TECHNOLOGY ADVANCES IN DIGITAL LIBRARIES LA English DT Proceedings Paper CT IEEE Forum on Research and Technology Advances in Digital Libraries CY MAY 19-21, 1999 CL BALTIMORE, MD SP IEEE Comp Soc, Tech Comm Digital Lib, Rutgers, CIMIC, Forsch Zentrum Informat Technik GmbH, Natl Lib Med, NASA, CESDIS, GTE Labs, Oracle Corp, Sun Microsyst, Silicon Graph C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hughes, JS (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 COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1092-9959 BN 0-7695-0219-9 J9 P IEEE INT FORUM RES PY 1999 BP 86 EP 86 DI 10.1109/ADL.1999.777695 PG 1 WC Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Computer Science GA BN77E UT WOS:000082879600009 ER PT S AU Halem, M Hoban, S AF Halem, M Hoban, S GP IEEE COMP SOC IEEE COMP SOC TI Digital Earth SO IEEE FORUM ON RESEARCH AND TECHNOLOGY ADVANCES IN DIGITAL LIBRARIES, PROCEEDINGS SE PROCEEDINGS - IEEE INTERNATIONAL FORUM ON RESEARCH AND TECHNOLOGY ADVANCES IN DIGITAL LIBRARIES LA English DT Proceedings Paper CT IEEE Forum on Research and Technology Advances in Digital Libraries CY MAY 19-21, 1999 CL BALTIMORE, MD SP IEEE Comp Soc, Tech Comm Digital Lib, Rutgers, CIMIC, Forsch Zentrum Informat Technik GmbH, Natl Lib Med, NASA, CESDIS, GTE Labs, Oracle Corp, Sun Microsyst, Silicon Graph C1 NASA, GSFC, Greenbelt, MD 20771 USA. RP Halem, M (reprint author), NASA, GSFC, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1092-9959 BN 0-7695-0219-9 J9 P IEEE INT FORUM RES PY 1999 BP 96 EP 96 DI 10.1109/ADL.1999.777701 PG 1 WC Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Computer Science GA BN77E UT WOS:000082879600014 ER PT B AU Menzies, T Easterbrook, S Nuseibeh, B Waugh, S AF Menzies, T Easterbrook, S Nuseibeh, B Waugh, S GP IEEE IEEE TI An empirical investigation of multiple viewpoint reasoning in requirements engineering SO IEEE INTERNATIONAL SYMPOSIUM ON REQUIREMENTS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 4th IEEE International Symposium on Requirement Engineering (RE 99) CY JUN 07-11, 1999 CL UNIV LIMERICK, LIMERICK, IRELAND SP IEEE Comp Soc TC Software Engn, ACM SIGSOFT, IFIP Working Grp 2.9, RENOIR HO UNIV LIMERICK ID ABDUCTION AB Multiple viewpoints are often used in Requirements Engineering to facilitate traceability to stakeholders, to structure the requirements process, and to provide richer modelling by incorporating multiple conflicting descriptions. In the latter case, the need to reason with inconsistent models; introduces considerable extra complexity. This paper describes an empirical study of the utility of multiple world reasoning (using abduction)far domain modelling. In the study we used a range of different models (ranging from correct to very incorrect), different fanouts, different amounts of data available from the domain, and different modelling primitives for representing time. In the experiments there was no significant change in the expressive power of models that incorporate multiple conflicting viewpoints. Whilst this does not negate the advantages of viewpoints during requirements elicitation, it does suggest some limits to the utility of viewpoints during requirements modelling. C1 NASA, WVU Software Res Lab, Fairmont, WV 26654 USA. RP Menzies, T (reprint author), NASA, WVU Software Res Lab, Fairmont, WV 26654 USA. NR 29 TC 2 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0188-5 PY 1999 BP 100 EP 109 DI 10.1109/ISRE.1999.777990 PG 10 WC Computer Science, Software Engineering SC Computer Science GA BN33C UT WOS:000081640800016 ER PT J AU Barnes, NP Walsh, BM AF Barnes, NP Walsh, BM TI Amplified spontaneous emission - Application to Nd : YAG lasers SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE amplified spontaneous emission; Nd : YAG; solid-state lasers AB Amplified spontaneous emission can seriously degrade the Q-switched performance of a strong four-level transition such as the 1.064 Irm Nd:YAG transition or can even prevent oscillation on a weaker quasi-four-level transition such as the 0.946-mu m Nd:YAG transition, To characterize, and thus be able to mitigate, amplified spontaneous emission, a closed-form model is developed. By employing a closed-form solution, the differential equations describing both the evolution and decay of the upper laser manifold population density can be solved exactly. An advantage of this model is the separation of the spectral and spatial portions of amplified spontaneous emission. Gain measurements, as a function of time and pump energy, are compared with the model and good agreement is found. With these principles in mind, a flashlamp-pumped Nd:YAG laser was designed to operate at 0.946 mu m. At room temperature, a threshold of 12 J and a slope efficiency of 0.009 was achieved. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Boston Coll, Chestnut Hill, MA 02167 USA. RP Barnes, NP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 18 TC 68 Z9 70 U1 1 U2 13 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD JAN PY 1999 VL 35 IS 1 BP 101 EP 109 DI 10.1109/3.737626 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 152EZ UT WOS:000077764400016 ER PT J AU Waters, R Patterson, J Van Zeghbroeck, B AF Waters, R Patterson, J Van Zeghbroeck, B TI Micromechanical optoelectronic switch and amplifier (MIMOSA) SO IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS LA English DT Article DE cavity resonant filter; Fabry-Perot interferometers; filters; membranes; microelectromechanical devices; micromachining; modulation; tunable filter; voltage control AB We report for the first time the monolithic integration of a micromechanical modulator and a p-n photodiode on a silicon substrate yielding a versatile optoelectronic device, Because both devices are monolithically integrated on a silicon substrate, the combination is compact with minimal parasitic elements. We demonstrate that such a device combination yields a transistor-like element with positive and negative small-signal voltage amplification, The maximum small-signal voltage gain achieved is 500 while the modulated current of the device exhibits a maximum ON-OFF ratio of 3:1, In addition, while the theoretical current gain of the device is infinite, a 10-pA noise level limited the measured de current gain to 10(6). C1 Univ Colorado, Dept Elect Engn, Boulder, CO 80309 USA. Univ Colorado, Optoelect Comp Syst Ctr, Boulder, CO 80309 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Waters, R (reprint author), Univ Colorado, Dept Elect Engn, Boulder, CO 80309 USA. NR 10 TC 5 Z9 5 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1077-260X J9 IEEE J SEL TOP QUANT JI IEEE J. Sel. Top. Quantum Electron. PD JAN-FEB PY 1999 VL 5 IS 1 BP 33 EP 35 DI 10.1109/2944.748102 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 190PK UT WOS:000079972900007 ER PT J AU Gat, E Ciholas, M AF Gat, E Ciholas, M TI Using Linux to build fast networks SO IEEE SOFTWARE LA English DT Article C1 NASA, Jet Propuls Lab, Pasadena, CA USA. Cedar Technol, Newburgh, IN USA. RP Gat, E (reprint author), NASA, Jet Propuls Lab, Pasadena, CA 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 90720-1314 USA SN 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD JAN-FEB PY 1999 VL 16 IS 1 BP 78 EP 78 PG 1 WC Computer Science, Software Engineering SC Computer Science GA 160BY UT WOS:000078211500033 ER PT J AU White, AL AF White, AL TI Two matrix norm conditions for asymptotic stability in the presence of controller disturbances SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Article DE asynchronous; multirate; stability tests; stochastic; synchronous AB The stability analysis for digital control systems is extended to consider controller misbehavior. This approach shows that it is possible for a system to survive repeated controller perturbations because of plant dynamics. This idea is placed on a quantitative basis by deriving results about asymptotic stability in terms of matrix norms. These results are intended to be both general in application and convenient for experiments. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP White, AL (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM a.l.white@larc.nasa.gov NR 14 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9286 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD JAN PY 1999 VL 44 IS 1 BP 169 EP 172 DI 10.1109/9.739115 PG 4 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA 155YV UT WOS:000077975300029 ER PT J AU Simon, MK Alouini, MS AF Simon, MK Alouini, MS TI A unified performance analysis of digital communication with dual selective combining diversity over correlated Rayleigh and Nakagami-m fading channels SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article; Proceedings Paper CT 7th Communication Theory Mini-Conference in conjunction with IEEE Global Communication Conference (Globecom 98) CY NOV, 1998 CL SYDNEY, AUSTRALIA SP IEEE Commun Soc DE fading correlation; Nakagami fading; selection combining diversity ID RECEPTION; SIGNALS AB Using a simple finite integral representation for the bivariate Rayleigh cumulative distribution function recently discovered by the authors, we present expressions for the outage probability and average error probability performances of a dual selective diversity system with correlated slow Rayleigh fading either in closed form (in particular for binary differential phase-shift keying) or in terms of a single integral with finite limits and an integrand composed of elementary (exponential and trigonometric) functions. Because of their simple form, these expressions readily allow numerical evaluation for cases of practical interest, The results are also extended to the case of slow Nakagami-m fading using an alternate representation of the generalized Marcum Q-function. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Dept Elect Engn, Commun Grp, Pasadena, CA 91109 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 27 TC 89 Z9 89 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD JAN PY 1999 VL 47 IS 1 BP 33 EP 43 DI 10.1109/26.747811 PG 11 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 169FC UT WOS:000078736000008 ER PT J AU Johnson, JT Shin, RT Kong, JA Tsang, L Pak, K AF Johnson, JT Shin, RT Kong, JA Tsang, L Pak, K TI A numerical study of ocean polarimetric thermal emission SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE emission; remote sensing; rough surfaces ID MONTE-CARLO SIMULATIONS; RANDOM ROUGH SURFACES; BACKSCATTERING ENHANCEMENT; ELECTROMAGNETIC-WAVES; IMPROVED MODEL; SEA-SURFACE; WATER AB A numerical model for polarimetric thermal emission from penetrable ocean surfaces rough in two directions is presented, The numerical model is based on Monte Carlo simulation with an iterative version of the method of moments (MOM) known as the sparse matrix flat surface iterative approach (SMF-SIA), extended to the penetrable surface case through a numerical impedance boundary condition (NIBC) method, Since the small U-B brightnesses obtained from ocean surfaces (usually less than 1.5 K, or 0.5% of a 300-K physical temperature) require extremely accurate simulations to avoid large errors, a parallel version of the algorithm is developed to allow matrix elements to be integrated accurately and stored, The high accuracy required also limits simulations to near Bat surface profiles, so that only high-frequency components of the ocean spectrum are modeled, Variations in nadir polarimetric brightness temperatures with spectrum low- and high-frequency cutoffs show the Bragg (or shortwave) portion of the spectrum to contribute significantly to emission azimuthal signatures, as predicted by the small perturbation or composite surface approximate theories, Quantitative comparisons with approximate methods show perturbation theory to slightly overestimate linear brightness temperatures, but accurately predict their azimuthal variations, while physical optics (PO) significantly underestimates both linear brightness temperatures and their azimuthal variations, Further simulations with the numerical model allow sensitivities to ocean spectrum models to be investigated and demonstrate the importance of an accurate azimuthal description for the ocean spectrum. C1 Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. MIT, Dept Elect Engn, Cambridge, MA 02139 USA. MIT, Elect Res Lab, Cambridge, MA 02139 USA. Univ Washington, Dept Elect Engn, Electromagnet & Remote Sensing Lab, Seattle, WA 98195 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnson, JT (reprint author), Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. NR 36 TC 39 Z9 39 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 8 EP 20 DI 10.1109/36.739089 PN 1 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NU UT WOS:000078122300002 ER PT J AU Reul, N Branger, H Bliven, LF Giovanangeli, JP AF Reul, N Branger, H Bliven, LF Giovanangeli, JP TI The influence of oblique waves on the azimuthal response of a Ku-band scatterometer: A laboratory study SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE azimuthal response; oblique waves; scatterometer; sea surface ID RADAR CROSS-SECTION; AFFECTING MICROWAVE BACKSCATTER; TURBULENT BOUNDARY-LAYER; WIND-WAVES; SURFACE-WAVES; WATER-WAVES; STRESS; SEA; DEPENDENCE; OCEAN AB We conducted experiments in the large wind-wave tank at IRPHE1 to examine the influence of longer waves propagating at oblique angles to the mind direction on microwave backscattering. Measurements were made of wind, wave directional spectra, and cross sections from a 13.5-GHz scatterometer at 30 degrees from nadir incidence angle, We characterize the scatterometric azimuthal scans with respect to the magnitude and the direction of the maximum backscattered power. Scans of solely wind waves are used to assess the effects of oblique waves, for which the scans yield trends that are related to the oblique-wave direction relative to the wind and the oblique-wave steepness, in particular, cross-section maxima are enhanced by oblique waves and the direction of marina rotates from the wind axis toward the oblique-wave direction. These scatterometer data, in addition to other oblique-wave studies, led us to conclude that wind vectors produced from standard retrieval algorithms for scatterometers should be used with prudence in regions with significant veering winds, such as near meteorological fronts. C1 Inst Rech Phenomenes Hors Equilibre, Lab Ocean Atmosphere, F-13288 Marseille 9, France. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Lab Hydrospher Proc, Wallops Island, VA 23337 USA. RP Reul, N (reprint author), Inst Rech Phenomenes Hors Equilibre, Lab Ocean Atmosphere, Parc Sci Luminy, F-13288 Marseille 9, France. RI reul, nicolas/C-4895-2009; bliven, francis/E-1450-2012; Branger, Hubert/E-1879-2016 OI Branger, Hubert/0000-0002-9888-681X NR 53 TC 4 Z9 4 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 36 EP 47 DI 10.1109/36.739094 PN 1 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NU UT WOS:000078122300004 ER PT J AU Njoku, EG Rahmat-Samii, Y Sercel, J Wilson, WJ Moghaddam, M AF Njoku, EG Rahmat-Samii, Y Sercel, J Wilson, WJ Moghaddam, M TI Evaluation of an inflatable antenna concept for microwave sensing of soil moisture and ocean salinity SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aperture antennas; hydrology; inflatable antennas; microwave radiometry; ocean salinity or sea surface salinity; remote sensing; soil moisture ID RADIOMETER; PATTERN; FIFE AB A spaceborne inflatable antenna concept is evaluated for passive microwave sensinlkg of soil moisture and ocean salinity. The concept makes use of a large-diameter, offset-fed, parabolic-torus antenna with multiple feeds in a conical pushbroom configuration. An inflatable structure provides the means for deploying the large-aperture, low-mass, and low-cost antenna system in space, suitable for operation in the 1-3-GHz frequency range needed for soil moisture and salinity sensing. The concept is designed to provide multichannel, constant-incidence-angle, wide-swath, and high-radiometric-precision observations of the earth's surface. These capabilities facilitate estimation of soil moisture and salinity, with global coverage every two to three days, Simulations show that a 25-m diameter, 1.41- and 2.69-GHz, dual-polarized system should be capable of providing surface soil moisture estimates with an accuracy of similar to 0.04 g-cm(-3) (where vegetation water content is less than similar to 5 kg-m(-2)) at a spatial resolution of similar to 30 km, Although inflatable systems represent a new and untested technology for remote-sensing applications, the advantages of low packaged volume, low manufacturing cost, and low mass provide an incentive for their study. This paper evaluates one possible concept for incorporating the capabilities of inflatable systems into a scientific mission and for demonstrating these capabilities for remote-sensing applications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. RP Njoku, EG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM eni.g.njoku@jpl.nasa.gov NR 47 TC 25 Z9 25 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 63 EP 78 DI 10.1109/36.739121 PN 1 PG 16 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NU UT WOS:000078122300007 ER PT J AU Njoku, EG Li, L AF Njoku, EG Li, L TI Retrieval of land surface parameters using passive microwave measurements at 6-18 GHz SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE hydrology; inverse problems; microwave radiometry; remote sensing; soil; vegetation ID PLANT WATER-CONTENT; SOIL-MOISTURE; POLARIZATION DIFFERENCE; BRIGHTNESS TEMPERATURES; INVERSE PROBLEMS; 37 GHZ; VEGETATION; MODEL; SMMR; EMISSION AB An approach is evaluated for retrieval of land surface parameters (soil moisture, vegetation water content, and surface temperature) using satellite microwave radiometer data in the 6-18-GHz frequency range, The approach is applicable to data that will be acquired by the Advanced Microwave Scanning Radiometer (AMSR), planned for launch on the Japanese Advanced Earth Observing Satellite (ADEOS)-II and Earth Observing System (EOS) PM-1 platforms in 1999 and 2000, respectively. The retrieval method is based on a radiative transfer (RT) model for land-surface and atmospheric emission, with model coefficients that can be tuned over specific calibration regions and applied globally. The method uses an iterative, least-squares algorithm, based on six channels of radiometric data. Simulations using this algorithm indicate that, for an assumed sensor noise of 0.3 K in all channels, soil moisture and vegetation water content retrieval accuracies of 0.06 g cm(-3) and 0.15 kg m(-2), respectively, should be achievable in regions of vegetation water content less than approximately 1.5 kg m(-2), A surface temperature accuracy of 2 C should be achievable, except for bare soils, where discrimination between moisture and temperature variability is difficult using this algorithm. These accuracies are for retrievals averaged over the sensor footprint, and they exclude conditions of precipitation, open water, snow cover, frozen ground, or high topographic relief within the footprint. The algorithm has been tested using data from the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) for the years 1982-1985, over the African Sahel, and the retrieval results compared to output from an operational numerical weather prediction model, The retrieval algorithm is shown to discriminate well between soil moisture, vegetation, and temperature variations and provide estimates consistent with the expected accuracies, Future work will investigate possible improvements to the algorithm using alternate formulations, possibly with fewer channels, and extend testing of the algorithm to other regions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Njoku, EG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM eni.g.njoku@jpl.nasa.gov NR 54 TC 299 Z9 350 U1 5 U2 52 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 79 EP 93 DI 10.1109/36.739125 PN 1 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NU UT WOS:000078122300008 ER PT J AU Gu, DG Gillespie, AR Adams, JB Weeks, R AF Gu, DG Gillespie, AR Adams, JB Weeks, R TI A statistical approach for topographic correction of satellite images by using spatial context information SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE forest mapping; image classification; remote sensing; spatial contextual information; topographic correction ID TM DATA; NORMALIZATION; REFLECTANCE; TERRAIN AB The geometric and systematic errors associated with the acquisition and coregistration of a satellite image and digital terrain model (DTM) will significantly affect the results of topographic corrections, The conventional pixel-based topographic correction methods have not handled these errors well. The corrected images, although exhibiting no significant residual topography in average, usually show high and nonhomogenous variability across the scene. In this paper, me propose a contextual approach for minimizing this artifactual and undesirable feature in the corrected images. The new approach compensates the topographic shading and shadowing by using the local reflectance estimated from the spatial contexts. Since the noises have much less effects on the extracted contextual information, errors are reduced for the estimated reflectance and the signal-to-noise ratios are improved on the shaded slopes. As a result, not only is the variance lower and spatially more homogenous, the fine textures and community boundaries are also well preserved on the corrected images. For the purpose of image interpretation, the reduced variability for each cover type may lead to significant improvements of land cover differentiation, In the testing site of a forested scene, for example, the overall classification accuracy has improved about 9% in the contextually corrected image over the conventionally corrected images. C1 Univ Washington, Dept Geol Sci 351310, Seattle, WA 98195 USA. RP Gu, DG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 15 Z9 19 U1 0 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 236 EP 246 DI 10.1109/36.739158 PN 1 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NU UT WOS:000078122300022 ER PT J AU Lyapustin, AI AF Lyapustin, AI TI A method for determining atmospheric optical parameters and surface albedo from multiangle, satellite measurements: Sea surface applications SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosol; algorithms; optical thickness; reflection; remote sensing; scattering function ID IMAGERY AB A new method is presented for determining the atmospheric optical thickness, aerosol scattering function, and surface albedo using measurements of the upward radiance at different view angles. It is applicable over the surface with reflectance not exceeding approximate to 10%. The suggested approach is based on forming the data bank of aerosol scattering functions, complete enough in a sense of describing the real diversity of atmospheric phase functions both over sea and land. A performed sensitivity study shows that the error of determining the optical thickness does not exceed 10-15%. Aerosol absorption and anisotropy of the surface in typical conditions can induce additional errors up to 10 and 15%. Over the surface of Lambertian type, albedo is retrieved with an error less than 0.01, whereas over the anisotropic surface, it turns out to be close to the product of the hemispheric surface albedo and a factor of surface anisotropy. For the typical viewing geometry, characterized by fixed azimuth and varying zenith view angle, this method gives the best choice of scattering function from the data bank in a sense of proximity of its shape and anisotropy factor to those of the true atmospheric scattering function. Experimental applications of the method to the multiangle data of spectrometer MKS-M2, collected over the Caspian Sea, shows its utility in the remote sensing of atmospheric aerosol and surface albedo. C1 NASA, Univ Space Res Assoc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lyapustin, AI (reprint author), NASA, Univ Space Res Assoc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Lyapustin, Alexei/H-9924-2014 OI Lyapustin, Alexei/0000-0003-1105-5739 NR 23 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 277 EP 286 DI 10.1109/36.739162 PN 1 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NU UT WOS:000078122300026 ER PT J AU Hussein, ZA Rahmat-Samii, Y AF Hussein, ZA Rahmat-Samii, Y TI Application of cylindrical near-field measurement technique to the calibration of spaceborne radar antennas: NASA scatterometer and SeaWinds SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE antenna measurements; cylindrical near-field measurements; near-held error analysis; radar antenna calibration AB Modern spaceborne radar scatterometers, such as the NASA scatterometer (NSCAT) and SeaWinds radar instruments, require precise determination of the normalized backscattered radar cross section within a few tenth of a decibel, This is needed to achieve the desired wind velocity and direction measurement accuracy of 2 mis and 20 degrees, respectively. This high level of precision demands a priori prelaunch accurate knowledge and determination of the radar antenna's absolute gain and relative radiation patterns characteristics over wide angular range. such characterizations may be performed on a far-field range, compact range, or in an indoor near-field measurement Facility, Among the unique advantage of the near-held measurement is that most of the information of the radar antenna radiation properties fan be obtained anywhere outside the near-field measurement surface. Two recently designed radar scatterometers are considered in this paper, NASA scatterometer (NSCAT) and SeaWinds, to demonstrate the utility of a newly completed cylindrical near-field measurement range. As an example of an advanced calibration methodology, the data based on a recently measured JPL/NASA scatterometer (NSCAT) radar antenna are used to experimentally demonstrate the role of the probe pattern compensation, probe multiple reflection effects, probe mispositioning effects, scan area truncation effects, etc, A measurement lest on a standard gain horn (SGH) has been performed to achieve and verify the absolute gain calibration accuracy. A comparison between direct far-field measured data and those obtained from cylindrical near-field measurements for the SeaWinds radar antenna was found in excellent agreement. Tt is demonstrated that the near-field measurement technique is a viable approach in accurately characterizing the performance of spaceborne radar antennas. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. RP Hussein, ZA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 23 TC 0 Z9 0 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 360 EP 373 DI 10.1109/36.739069 PN 2 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NY UT WOS:000078122700004 ER PT J AU Costantini, M Farina, A Zirilli, F AF Costantini, M Farina, A Zirilli, F TI A fast phase unwrapping algorithm for SAR interferometry SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE interferometry; phase unwrapping; synthetic aperture radar (SAR) ID SYNTHETIC APERTURE RADARS; FORMULATION AB Phase unwrapping is the key problem in building the elevation map of a scene from interferometric synthetic aperture radar (SAR) system data. Phase unwrapping consists in the reconstruction of the phase difference of the radiation received by two SAR systems as a function of the azimuth and slant range coordinates. The data available to reconstruct the phase difference are a measure of the difference module 2 pi, We propose a phase unwrapping method that makes use of the equivalent, in a discrete space, of the irrotational property of a gradient vector field. This property if used first to locate the areas where the discrete vector held estimated from the available data must be corrected, and then, with the knowledge of some a priori information, to perform the correction needed to obtain a useful estimate of the discrete gradient of the phase difference function, from which the phase difference function is reconstructed. The use of the fast Fourier transform makes it possible to have a fast algorithm, that is to process an image of N pixel in 0(N log N) elementary operations. Tests of the method proposed here on real and simulated data are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Area Sistemi Alenia, I-00131 Rome, Italy. Univ Rome La Sapienza, Dipartimento Matemat G Castelnuovo, I-00185 Rome, Italy. RP Costantini, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 23 TC 37 Z9 38 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 452 EP 460 DI 10.1109/36.739085 PN 2 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NY UT WOS:000078122700010 ER PT J AU Lyapustin, AI Muldashev, TZ AF Lyapustin, AI Muldashev, TZ TI Multiangle monitoring of atmospheric aerosol and surface reflectance from MIR station SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB This paper presents the data of a series of multiangle experiments performed from the orbital station MIR in 1993-1994 over the semiarid regions of Kazakstan and the forest test sites of Zabaikal'e and Khabarovsky Krai (Russia), Collected data were processed to obtain the optical thickness and scattering function of atmospheric aerosol and surface albedo in ten spectral bands of spectrometer MKS-M2. To this end, the following approach was adopted. In the visible part of the spectrum, where the reflectance of observed surfaces is relatively low, they were assumed to be Lambertian, On this basis, spectral dependencies of the above parameters were obtained using the multiangle method reported earlier. In the near-infrared (NIR) part of the spectrum, where the surface reflectance is considerable and its anisotropy gives a substantial contribution to the angular dependence of radiance, the optical thickness was obtained via the extrapolation from the visible spectral interval and then the effective surface albedo was estimated from measurements. To test the validity of the Lambertian assumption, a qualitative criterion is suggested. Obtained results were also verified by the ground albedo measurements: spectral albedo retrieved for the semiarid terrain and the measurements in subsatellite point coincided with the average accuracy 0.01. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Space Res Inst, Alma Ata, Kazakhstan. RP Lyapustin, AI (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. EM alyapustin@pop900.gsfc.nasa.gov RI Lyapustin, Alexei/H-9924-2014 OI Lyapustin, Alexei/0000-0003-1105-5739 NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1999 VL 37 IS 1 BP 589 EP 595 DI 10.1109/36.739122 PN 2 PG 7 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 158NY UT WOS:000078122700024 ER PT J AU Manohar, M Tilton, JC AF Manohar, M Tilton, JC TI Model-based vector quantization with application to remotely sensed image data SO IEEE TRANSACTIONS ON IMAGE PROCESSING LA English DT Article DE data compression; image coding; vector quantization ID TRANSMISSION; ALGORITHM AB Model-based vector quantization (MVQ) is introduced here as a variant of vector quantization (VQ), MVQ has the asymmetrical computational properties of conventional VQ, but does not require the use of pregenerated codebooks, This is a great advantage, since codebook generation is usually a computationally intensive process, and maintenance of codebooks for coding and decoding can pose difficulties. MVQ uses a simple mathematical model for mean removed errors combined with a human visual system model to generate parameterized codebooks, The error model parameter (lambda) is included with the compressed image as side information from which the same codebook is regenerated for decoding. As far as the user is concerned, MVQ is a codebookless VQ variant. After a brief introduction, the problems associated with codebook generation and maintenance are discussed. We then give a description of the MVQ algorithm, followed by an evaluation of the performance of MVQ on remotely sensed image data sets from NASA sources. The results obtained with MVQ are compared with other VQ techniques and JPEG/DCT. Finally, we demonstrate the performance of MVQ as a part of a progressive compression system suitable for use in an image archival and distribution installation. C1 Bowie State Univ, Dept Comp Sci, Bowie, MD 20715 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Manohar, M (reprint author), Bowie State Univ, Dept Comp Sci, Bowie, MD 20715 USA. NR 20 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1057-7149 J9 IEEE T IMAGE PROCESS JI IEEE Trans. Image Process. PD JAN PY 1999 VL 8 IS 1 BP 15 EP 21 DI 10.1109/83.736678 PG 7 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 154CW UT WOS:000077871900002 PM 18262861 ER PT J AU Simons, RN Lee, RQ AF Simons, RN Lee, RQ TI On-wafer characterization of millimeter-wave antennas for wireless applications SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE gain; input impedance of antenna; linearly tapered slot antenna; mutual coupling; on-wafer characterization; TRL calibration standards AB This paper demonstrates a deembedding technique and a direct on-substrate measurement technique for fast and inexpensive characterization of miniature antennas for wireless applications at millimeterwave frequencies. The technique is demonstrated by measurements on a tapered slot antenna (TSA). The measured results at Ka-band frequencies include input impedance, mutual coupling between two TSA's, and absolute gain of TSA. C1 NASA, Lewis Res Ctr, NYMA Grp, Cleveland, OH 44135 USA. RP Simons, RN (reprint author), NASA, Lewis Res Ctr, NYMA Grp, Cleveland, OH 44135 USA. NR 8 TC 17 Z9 17 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD JAN PY 1999 VL 47 IS 1 BP 92 EP 96 DI 10.1109/22.740086 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA 158DE UT WOS:000078100100015 ER PT B AU Owens, K Matthies, L AF Owens, K Matthies, L GP IEEE COMP SOC IEEE COMP SOC TI Passive night vision sensor comparison for unmanned ground vehicle stereo vision navigation SO IEEE WORKSHOP ON COMPUTER VISION BEYOND THE VISIBLE SPECTRUM: METHODS AND APPLICATIONS (CVBVS'99) - PROCEEDINGS LA English DT Proceedings Paper CT IEEE Workshop on Computer Vision Beyond the Visible Spectrum - Methods and Applications (CVBVS 99) CY JUN 22, 1999 CL FT COLLINS, CO SP IEEE, IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence AB One goal of the "Demo III" unmanned ground vehicle program is to enable autonomous nighttime navigation at speeds of up to 10 m.p.h. To perform obstacle detection at night with stereo vision will require night vision cameras that produce adequate image quality for the driving speeds, vehicle dynamics, obstacle sizes, and scene conditions that will be encountered. This paper analyzes the suitability of four classes of night vision cameras (3-5 mu m cooled FLIR, 8-12 mu m cooled FLIR, 8-12 mu m uncooled FLIR, and image intensifiers) for night stereo vision, using criteria based on stereo matching quality, image signal to noise ratio, motion blur, and synchronization capability We find that only cooled FLIRs will enable stereo vision performance that meets the goals of the Demo III program for nighttime autonomous mobility. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Owens, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 4 Z9 4 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 0-7695-0050-1 PY 1999 BP 59 EP 68 DI 10.1109/CVBVS.1999.781095 PG 10 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BN32P UT WOS:000081630700007 ER PT B AU Inge, JT Sydnor, GH Lubasch, R Bhatia, R Krattiger, H AF Inge, JT Sydnor, GH Lubasch, R Bhatia, R Krattiger, H GP IEEE IEEE TI Commissioning and operational experience for the 135,000 HP adjustable speed drive at NASA's National Transonic Facility SO IEMDC'99 - IEEE INTERNATIONAL ELECTRIC MACHINES AND DRIVES CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Electric Machines and Drives Conference (IEMDC 99) CY MAY 09-12, 1999 CL SEATTLE, WA SP IEEE, IEEE, Power Engn Soc, IEEE, Ind Applicat Soc AB The world's largest adjustable speed drive system is now operational at NASA's National Transonic Facility. The successful activation of this newly installed system was achieved through structured factory tests and a comprehensive commissioning plan. Data from the commissioning tests are presented. The tests validate the design, characterize the operational envelope, and demonstrate that performance requirements were met. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Inge, JT (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 4 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5293-9 PY 1999 BP 694 EP 697 DI 10.1109/IEMDC.1999.769217 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BN28R UT WOS:000081429300207 ER PT B AU Smith, DE Weld, DS AF Smith, DE Weld, DS GP IJCAII IJCAII IJCAII TI Temporal planning with mutual exclusion reasoning SO IJCAI-99: PROCEEDINGS OF THE SIXTEENTH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, VOLS 1 & 2 LA English DT Proceedings Paper CT 16th International Joint Conference on Artificial Intelligence (IJCAI 99) CY JUL 31-AUG 06, 1999 CL STOCKHOLM, SWEDEN SP Int Joint Conference Artificial Intelligence Inc, Scandinavian Al Soc AB Many planning domains require a richer notion of time in which actions can overlap and have different durations. The key to fast performance in classical planners (e.g., Graphplan, IPP, and Blackbox) has been the use of a disjunctive representation with powerful mutual exclusion reasoning. This paper presents TGP, a new algorithm for temporal planning. TGP operates by incrementally expanding a compact planning graph representation that handles actions of differing duration. The key to TGP performance is tight mutual exclusion reasoning which is based on an expressive language for bounding mutexes and includes mutexes between actions and propositions. Our experiments demonstrate that mutual exclusion reasoning remains valuable in a rich temporal setting. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Smith, DE (reprint author), NASA, Ames Res Ctr, Mail Stop 269-2, Moffett Field, CA 94035 USA. NR 15 TC 7 Z9 7 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA BN 1-55860-613-0 PY 1999 BP 326 EP 333 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BR27X UT WOS:000165996800048 ER PT B AU Morris, P Muscettola, N AF Morris, P Muscettola, N GP IJCAII IJCAII IJCAII TI Managing temporal uncertainty through waypoint controllability SO IJCAI-99: PROCEEDINGS OF THE SIXTEENTH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, VOLS 1 & 2 LA English DT Proceedings Paper CT 16th International Joint Conference on Artificial Intelligence (IJCAI 99) CY JUL 31-AUG 06, 1999 CL STOCKHOLM, SWEDEN SP Int Joint Conference Artificial Intelligence Inc, Scandinavian Al Soc AB Simple Temporal Networks have proved useful in applications that involve metric time. However, many applications involve events whose timing is not controlled by the execution agent. A number of properties relating to overall controllability in such cases have been introduced in [Vidal and Ghallab, 1996] and [Vidal and Fargier, 1997], including Weak and Strong Controllability. We derive some new results concerning; these properties. In particular, we prove the negation of Weak Controllability is NP-hard, confirming a conjecture in [Vidal and Fargier, 1997]. We also introduce a more general controllability property of which Weak and Strong Controllability are special cases. A propagation algorithm is provided for determining whether the property holds, and we identify tractable cases where the algorithm runs in polynomial time. C1 NASA, Ames Res Ctr, Caelum Res, Moffett Field, CA 94035 USA. RP Morris, P (reprint author), NASA, Ames Res Ctr, Caelum Res, Mail Stop 269-1, Moffett Field, CA 94035 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA BN 1-55860-613-0 PY 1999 BP 1253 EP 1258 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BR27X UT WOS:000165996800178 ER PT S AU Bookout, PS Ricks, E AF Bookout, PS Ricks, E GP SPIE SPIE TI Evaluation of MPLM design and mission 6A coupled loads analyses SO IMAC - PROCEEDINGS OF THE 17TH INTERNATIONAL MODAL ANALYSIS CONFERENCE, VOLS I AND II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 17th International Modal Analysis Conference (IMAC) on Modal Analysis - Reducing the Time to Market CY FEB 08-11, 1999 CL KISSIMMEE, FL SP Soc Exptl Mech Inc AB Through the development of a space shuttle payload, there are usually several coupled loads analyses (CLA) performed: preliminary design, critical design, final design and verification loads analysis (VLA). A final design CLA is the last analysis conducted prior to model delivery to the shuttle program for the VLA. The finite element models used in the final design CLA and the VLA are test verified dynamic math models. Mission 6A is the first of many flights of the Multi-Purpose Logistics Module (MPLM). The MPLM was developed by Alenia Spazio S.p.A. (an Italian aerospace company) and houses the international Standard Payload Racks (ISPR) for transportation to the space station in the shuttle. Marshall Space Flight Center (MSFC), the payload integrator of the MPLM for Mission 6A, performed the final design CLA using the M6.0ZC shuttle data for liftoff and landing conditions using the proper shuttle cargo manifest. Alenia performed the preliminary and critical design CLAs for the development of the MPLM. However, these CLAs did not use the current Mission 6A cargo manifest. An evaluation of the preliminary and critical design performed by Alenia and the final design performed by MSFC is presented. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Bookout, PS (reprint author), NASA, George C Marshall Space Flight Ctr, ED23, Huntsville, AL 35812 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SOC EXPERIMENTAL MECHANICS INC PI BETHEL PA 7 SCHOOL ST, BETHEL, CT 06801 USA SN 0277-786X BN 0-912053-64-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3727 BP 758 EP 762 PG 5 WC Engineering, Aerospace; Engineering, Civil; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BM61W UT WOS:000079283700118 ER PT S AU Levine, MB AF Levine, MB GP SPIE SPIE TI On-orbit microdynamic behavior of a flexible structure: IPEX II SO IMAC - PROCEEDINGS OF THE 17TH INTERNATIONAL MODAL ANALYSIS CONFERENCE, VOLS I AND II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 17th International Modal Analysis Conference (IMAC) on Modal Analysis - Reducing the Time to Market CY FEB 08-11, 1999 CL KISSIMMEE, FL SP Soc Exptl Mech Inc AB The Interferometry Program Experiments (IPEX) I and II are the first free-flying space experiments specifically designed to characterize the sub-micron microdynamic behavior of large flexible optical structures subjected to on-orbit thermal-mechanical disturbances These technology demonstration flight experiments are precursors to the 10-meter baseline Space Interferometry Mission (SIM) scheduled to launch in 2005, and will address the mission's nanometer-level structural stability requirements. Of particular interest is the existence of dynamic instability mechanisms within joints and materials due to sudden thermal variations (a.k.a. thermal snap), or other internal strain energy redistribution events. This information is needed to characterize potentially uncontrollable high-frequency vibrational disturbances, and to validate structural designs and modeling approaches for joint-dominated extruding structures. The data obtained from IPEX-II, performed aboard the ASTRO-SPAS during the Space Shuttle STS-85 mission in August 1997, will be used to assess the magnitude and characteristics of these dynamic instabilities on a real flight structure. 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 6 TC 0 Z9 0 U1 0 U2 0 PU SOC EXPERIMENTAL MECHANICS INC PI BETHEL PA 7 SCHOOL ST, BETHEL, CT 06801 USA SN 0277-786X BN 0-912053-64-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3727 BP 915 EP 921 PG 7 WC Engineering, Aerospace; Engineering, Civil; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BM61W UT WOS:000079283700142 ER PT S AU Pappa, RS AF Pappa, RS GP SPIE SPIE TI GIF animation of mode shapes and other data on the Internet SO IMAC - PROCEEDINGS OF THE 17TH INTERNATIONAL MODAL ANALYSIS CONFERENCE, VOLS I AND II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 17th International Modal Analysis Conference (IMAC) on Modal Analysis - Reducing the Time to Market CY FEB 08-11, 1999 CL KISSIMMEE, FL SP Soc Exptl Mech Inc ID DATA-COMPRESSION AB The World Wide Web abounds with animated cartoons and advertisements competing for our attention. Most of these figures are animated Graphics Interchange Format (GIF) files. These flies contain a series of ordinary GIF images plus control information, and they provide an exceptionally simple, effective way to animate on the Internet. To date, however, this format has rarely been used for technical data, although there is no inherent reason not to do so. This paper describes a procedure for creating high-resolution animated GIFs of mode shapes and other types of structural dynamics data with readily available software. The paper shows three example applications using recent modal test data and video footage of a high-speed sled run. A fairly detailed summary of the GIF file format is provided in the appendix. All of the animations discussed in the paper are posted on the Internet at the following address: http://sdb-www.larc.nasa.gov/SDB/Research/data/pappa_data/imac17_figs.. C1 NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23681 USA. RP Pappa, RS (reprint author), NASA, Langley Res Ctr, Struct Dynam Branch, Hampton, VA 23681 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU SOC EXPERIMENTAL MECHANICS INC PI BETHEL PA 7 SCHOOL ST, BETHEL, CT 06801 USA SN 0277-786X BN 0-912053-64-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3727 BP 1130 EP 1144 PG 15 WC Engineering, Aerospace; Engineering, Civil; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BM61W UT WOS:000079283700176 ER PT S AU Cao, TT Zimmerman, DC James, GH AF Cao, TT Zimmerman, DC James, GH GP SPIE SPIE TI Identification of Ritz vectors from the space shuttle vertical stabilizer assembly test article SO IMAC - PROCEEDINGS OF THE 17TH INTERNATIONAL MODAL ANALYSIS CONFERENCE, VOLS I AND II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 17th International Modal Analysis Conference (IMAC) on Modal Analysis - Reducing the Time to Market CY FEB 08-11, 1999 CL KISSIMMEE, FL SP Soc Exptl Mech Inc AB Load dependent Ritz vectors have been demonstrated to offer great potential in the areas of finite element model correlation and structural damage detection. To verify the feasibility and accuracy of the new Ritz Realization Algorithm (RRA), dynamic response data and static test results from the Space Shuttle vertical stabilizer assembly experimental database are utilized. The cost of this new system identification procedure is minimum since it utilizes the same data used in a traditional modal survey test. Comparing to static test data, accurate Ritz vectors were extracted using data from accelerometer and laser scanning vibrometer modal survey tests. C1 NASA, Lyndon B Johnson Space Ctr, Struct & Dynam Branch, Houston, TX 77058 USA. RP Cao, TT (reprint author), NASA, Lyndon B Johnson Space Ctr, Struct & Dynam Branch, Houston, TX 77058 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SOC EXPERIMENTAL MECHANICS INC PI BETHEL PA 7 SCHOOL ST, BETHEL, CT 06801 USA SN 0277-786X BN 0-912053-64-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3727 BP 2005 EP 2010 PG 6 WC Engineering, Aerospace; Engineering, Civil; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BM61W UT WOS:000079283700301 ER PT S AU Mouroulis, P AF Mouroulis, P BE Descour, MR Shen, SS TI Spectral and spatial uniformity in pushbroom imaging spectrometers SO IMAGING SPECTROMETRY V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Imaging Spectrometry V CY JUL 19-21, 1999 CL DENVER, CO SP SPIE, Remote Sensing Soc DE pushbroom imaging spectrometer; spectrometer design; spatial and spectral uniformity AB Two simple and compact pushbroom spectrometer form are described that can satisfy stringent spectral and spatial uniformity requirements in terms of minimizing distortion as well as the variation of the pixel spectral and spatial response functions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mouroulis, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 17 Z9 17 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 0-8194-3239-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3753 BP 133 EP 141 DI 10.1117/12.366313 PG 9 WC Engineering, Aerospace; Geosciences, Multidisciplinary; Remote Sensing; Optics; Spectroscopy SC Engineering; Geology; Remote Sensing; Optics; Spectroscopy GA BP12B UT WOS:000084180200015 ER PT S AU Sutliff, TJ AF Sutliff, TJ BE Piuri, V Savino, M TI Space Acceleration Measurement System-II: Microgravity instrumentation for the International Space Station research community SO IMTC/99: PROCEEDINGS OF THE 16TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS. 1-3 SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 16th IEEE Instrumentation and Measurement Technology Conference CY MAY 24-26, 1999 CL VENICE, ITALY SP IEEE, Instrumentat & Measurement Soc, AEI, ANIPLA, FAST, IMEKO TC-4, Politecn Milano AB The International Space Station opens for business in the year 2000, rud with the opening, science investigations will take advantage of the unique conditions it provides as an on-orbit laboratory for research. With initiation of scientific studies comes a need to understand the environment present during research. The Space Acceleration Measurement System-II provides researchers a consistent means to understand the vibratory conditions present during experimentation on the International Space Station. The Space Acceleration Measurement System-II, or SAMS-II, detects vibrations present while the space station is operating. SAMS-II on-orbit hardware is comprised of two basic building block elements: a centralized control unit and multiple Remote Triaxial Sensors deployed to measure the acceleration environment at the point of scientific research, generally,within a research rack. Ground Operations Equipment is deployed to complete the command, control curd data telemetry elements of the SAMS-II implementation. Initially, operations consist of user requirements development, Measurement sensor deployment and use, rud data recovery on the ground Future system enhancements will provide additional user functionality ann support more simultaneous users. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Sutliff, TJ (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 1 Z9 2 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 0-7803-5277-7 J9 IEEE IMTC P PY 1999 BP 254 EP 259 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BN32J UT WOS:000081629700048 ER PT S AU Greenberg, PS Wernet, MP AF Greenberg, PS Wernet, MP BE Piuri, V Savino, M TI Quantitative velocity field measurements in reduced-gravity combustion science and fluid physics experiments SO IMTC/99: PROCEEDINGS OF THE 16TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS. 1-3 SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 16th IEEE Instrumentation and Measurement Technology Conference CY MAY 24-26, 1999 CL VENICE, ITALY SP IEEE, Instrumentat & Measurement Soc, AEI, ANIPLA, FAST, IMEKO TC-4, Politecn Milano ID PARTICLE AB Systems have been developed and demonstrated for performing quantitative velocity measurements in reduced-gravity combustion science and fluid physics investigations. The unique constraints and operational environments inherent to reduced-gravity experimental facilities pose special challenges to the development of hardware and software systems. Both point and planar velocimetric capabilities are described with particular attention being given to the development of systems to support the international Space Station laboratory. Emphasis has been placed on optical methods, primarily arising from the sensitivity of the phenomena of interest to intrusive probes. Limitations on available power, volume, data storage, and attendant expertise have motivated the use of solid-state sources and detectors, as well as efficient analysis capabilities emphasizing interactive data display and parameter control. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Greenberg, PS (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 0-7803-5277-7 J9 IEEE IMTC P PY 1999 BP 391 EP 396 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BN32J UT WOS:000081629700073 ER PT S AU Day, P Adriaans, MJ Klemme, B Sergatskov, D Duncan, R AF Day, P Adriaans, MJ Klemme, B Sergatskov, D Duncan, R BE Piuri, V Savino, M TI High resolution thermometers based on Pd(Mn) for studies of critical phenomena aboard the ISS SO IMTC/99: PROCEEDINGS OF THE 16TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS. 1-3 SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 16th IEEE Instrumentation and Measurement Technology Conference CY MAY 24-26, 1999 CL VENICE, ITALY SP IEEE, Instrumentat & Measurement Soc, AEI, ANIPLA, FAST, IMEKO TC-4, Politecn Milano ID HELIUM EXPERIMENT; POINT AB A high resolution thermometer was developed using a dilute alloy of Mn in Pd as the magnetic sensing element instead of the traditional paramagnetic salt. Use of the alloy material facilitated a significant decrease in the total mass of the device to about 3.5 g. The noise and drift of the device were measured and found to be comparable with that of the larger HRTs used on past flight experiments. The origin of the noise observed in stare-of-the-art HRTs and the potential of the new thermometric material for achieving lower noise figures is discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Day, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 0-7803-5277-7 J9 IEEE IMTC P PY 1999 BP 409 EP 412 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BN32J UT WOS:000081629700076 ER PT S AU Welander, P Barmatz, M Hahn, I AF Welander, P Barmatz, M Hahn, I BE Piuri, V Savino, M TI A new small nano-Kelvin resolution thermometer for low temperature experiments SO IMTC/99: PROCEEDINGS OF THE 16TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS. 1-3 SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 16th IEEE Instrumentation and Measurement Technology Conference CY MAY 24-26, 1999 CL VENICE, ITALY SP IEEE, Instrumentat & Measurement Soc, AEI, ANIPLA, FAST, IMEKO TC-4, Politecn Milano ID HEAT-CAPACITY; LAMBDA-POINT; HELIUM AB A small, high resolution paramagnetic susceptibility thermometer was developed using a GdCl3 paramagnetic salt. The device uses a SQUID (Superconducting Quantum interference Device) magnetometer to determine the temperature dependent magnetization of the salt in a magnetic field The magnetic field is provided by a pair of small samarium cobalt permanent magnet disks situated inside the thermometer housing. This eliminates the need for a heavy charging solenoid used in a conventional SQUID based magnetic thermometer system. This thermometer can resolve approximately 10(-9) K near the liquid-gas critical point of He-3 (similar to 3.31 K). The drift rate of the thermometer war measured to be < 2 x 10(-13) K/s. This light weight thermometer (similar to 7 g) is a candidate for use in future low temperature Space Shuttle and International Space Station experiments. The present thermometer design easily permits a variety of magnetic materials for use in other applications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Welander, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 0-7803-5277-7 J9 IEEE IMTC P PY 1999 BP 413 EP 416 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BN32J UT WOS:000081629700077 ER PT S AU DeLombard, R Hrovat, K McPherson, KM AF DeLombard, R Hrovat, K McPherson, KM BE Piuri, V Savino, M TI Comparison tools for assessing the microgravity environment of orbital missions, carriers and conditions SO IMTC/99: PROCEEDINGS OF THE 16TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS. 1-3 SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 16th IEEE Instrumentation and Measurement Technology Conference CY MAY 24-26, 1999 CL VENICE, ITALY SP IEEE, Instrumentat & Measurement Soc, AEI, ANIPLA, FAST, IMEKO TC-4, Politecn Milano AB The Principal Component Spectral Analysis and the Quasi-steady, Three-dimensional Histogram techniques provide the means to describe, on a single plot, the microgravity acceleration environment of a long period of time, such as a day, week, or month. This allows a straight forward comparison of the microgravity environment between microgravity increments on the International Space Station, locations within the International Space Station, and/or different operating conditions. Traditional data display methods (e.g. acceleration versus time), while adequate for shorter time periods, would utilize more plots for art extensive period of time, often making interpretation more difficult. These new techniques provide a single page representation of a large set of microgravity acceleration data. These techniques, in conjunction with other techniques, may be employed to derive useful information from acceleration data to characterize or compare the microgravity environment. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP DeLombard, R (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 0-7803-5277-7 J9 IEEE IMTC P PY 1999 BP 929 EP 934 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BN32J UT WOS:000081629700168 ER PT S AU Simmons, LL AF Simmons, LL BE Piuri, V Savino, M TI SIRTF, the Space Infrared Telescope Facility SO IMTC/99: PROCEEDINGS OF THE 16TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS. 1-3 SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 16th IEEE Instrumentation and Measurement Technology Conference CY MAY 24-26, 1999 CL VENICE, ITALY SP IEEE, Instrumentat & Measurement Soc, AEI, ANIPLA, FAST, IMEKO TC-4, Politecn Milano AB The Space Infrared Telescope Facility (SIRTF) is the last of the NASA Great Observatories, and a cornerstone of the NASA Origins Missions. The Observatory will include an 85 cm telescope in a unique orbit around the sun. The telescope will be launched at ambient temperature and cooled to 5.5 K in space. The science instruments will use large detector arrays that will be background limited, and capable of a broad range of astrophysical investigations. The SIRTF architecture will accommodate up to 5 years of cryogenic space operations This talk will describe both the scientific and technical capabilities of SIRTF. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Simmons, LL (reprint author), CALTECH, Jet Prop Lab, 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 SN 1091-5281 BN 0-7803-5277-7 J9 IEEE IMTC P PY 1999 BP 971 EP 974 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BN32J UT WOS:000081629700175 ER PT S AU Marr, J Dallas, S Laskin, R Unwin, S Yu, J AF Marr, J Dallas, S Laskin, R Unwin, S Yu, J BE Piuri, V Savino, M TI Space interferometry mission: Measuring the universe SO IMTC/99: PROCEEDINGS OF THE 16TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS. 1-3 SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 16th IEEE Instrumentation and Measurement Technology Conference CY MAY 24-26, 1999 CL VENICE, ITALY SP IEEE, Instrumentat & Measurement Soc, AEI, ANIPLA, FAST, IMEKO TC-4, Politecn Milano AB The Space Interferometry Mission (SIM) will be the NASA Origins Program's first space based long baseline interferometric observatory. SIM will use a 10 m Michelson stellar interferometer to provide 4 mu as precision absolute position measurements of stars down to 20th magnitude over its 5 yr. mission lifetime. SIM will also provide technology demonstrations of synthesis imaging and interferometric nulling. This paper describes the what, why and how of the SIM mission, including an overall mission & system description, science objectives, general description of how SIM makes its measurements, description of the design concepts now under consideration, operations concept, and supporting technology program. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Marr, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 301-486, Pasadena, CA 91109 USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 0-7803-5277-7 J9 IEEE IMTC P PY 1999 BP 1117 EP 1122 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BN32J UT WOS:000081629700200 ER PT S AU Shapiro, M Miller, E AF Shapiro, M Miller, E GP IEEE COMPUTER IEEE COMPUTER TI Managing databases with binary large objects SO INFORMATION-BASED ACCESS TO STORAGE: THE FOUNDATION OF INFORMATION SYSTEMS, PROCEEDINGS SE IEEE SYMPOSIUM ON MASS STORAGE SYSTEMS - PROCEEDINGS LA English DT Proceedings Paper CT 16th IEEE Symposium on Mass Storage Systems in Cooperation with the 7th NASA Goddard Conference on Mass Storage Systems and Technologies CY MAR 15-18, 1999 CL SAN DIEGO, CA SP IEEE, Comp Soc, Inst Elect & Electr Engineets Inc, NASA, Goddard Space Flight Ctr AB We present recommendations on Performance Management for databases supporting Binary Large Objects (BLOB) that, under a wide range of conditions, save both storage space and database transactions processing time. The research shows that for database applications where ad hoc retrieval queries prevail, storing the actual values of BLOBs in the database may be the best choice to achieve better performance, whereas storing BLOBs externally is the best approach where multiple Delete/Insert/Update operations on BLOBs dominate. Performance measurements are used to discover System Performance Bottlenecks and their resolution. We propose a strategy of archiving large data collections in order to reduce data management overhead in the Relational Database and maintain acceptable response time. C1 Univ Maryland Baltimore Cty, NASA, GSFC, Boeing IS, Baltimore, MD 21228 USA. RP Shapiro, M (reprint author), Univ Maryland Baltimore Cty, NASA, GSFC, Boeing IS, Baltimore, MD 21228 USA. NR 16 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 1051-9173 BN 0-7695-0204-0 J9 IEEE S MASS STOR SYS PY 1999 BP 185 EP 193 DI 10.1109/MASS.1999.830036 PG 9 WC Computer Science, Information Systems SC Computer Science GA BP90L UT WOS:000086558000018 ER PT S AU Rupert, AH McTrusty, TJ Peak, J AF Rupert, AH McTrusty, TJ Peak, J BE Wood, JL TI Haptic interface enhancements for navy divers SO INFORMATION SYSTEMS FOR NAVY DIVERS AND AUTONOMOUS UNDERWATER VEHICLES OPERATING IN VERY SHALLOW WATER AND SURF ZONE REGIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Information Systems for Navy Divers and Autonomous Underwater Vehicles Operating in Very Shallow Water and Surf Zone Regions CY APR 07-08, 1999 CL ORLANDO, FL SP SPIE DE haptic; touch; diver; spatial orientation; situation awareness; navigation; prosthesis AB Terrestrial orientation and navigation information is provided by three or more redundant, concordant, veridical, and independent sources of sensory information: the skin-muscle-joint somatosensory system, the inner ear vestibular apparatus, and the visual system. The frequent absence of contact with the bottom and the buoyancy provided by water render the skin-muscle-joint system ineffectual as a reliable source of sensory information. A novel device, utilizing the intuitive nature of the tactile/haptic system, has been developed to enhance the orientation performance of personnel in sensory deprived underwater environments. The tactile situation awareness system (TSAS) consists of sensors providing orientation, guidance, and or communication information to a collection of electromechanical stimulators (tactors) held in close contact with the skin. In preliminary tests, divers equipped with TSAS or traditional visual displays swam a triangular course to evaluate the possible benefits of tactile displays for use in the very shallow water diving environments. The TSAS permitted divers to navigate more accurately and offered information at a lower level of cognitive effort, thereby permitting divers to devote more attention to essential mission-related tasks. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Rupert, AH (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 13 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 0-8194-3185-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3711 BP 246 EP 252 DI 10.1117/12.354661 PG 7 WC Computer Science, Information Systems; Engineering, Marine SC Computer Science; Engineering GA BN69Y UT WOS:000082635900025 ER PT S AU Foote, MC AF Foote, MC BE Andresen, BF Scholl, MS TI Temperature stabilization requirements for unchopped thermal detectors SO INFRARED TECHNOLOGY AND APPLICATIONS XXV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Infrared Technology and Applications XXV Conference CY APR 05-09, 1999 CL ORLANDO, FL SP SPIE DE thermistor; bolometer; thermopile; detector; IR; thermal; temperature stabilization ID LINEAR ARRAYS; THERMOPILE AB The temperature stabilization requirements of unchopped thermistor bolometers and thermopile detectors are analyzed. The detector temperature, on which the bolometer output signal depends, is quite sensitive to changes in instrument temperature but relatively insensitive to changes in scene temperature. In contrast, the difference in temperature between detector and substrate (instrument), on which the thermopile signal depends, is equally sensitive to changes in instrument and scene temperature. Expressions for these dependencies are derived based on a simplified instrument model. It is shown that for a typical uncooled thermal imager, the temperature stabilization requirements for a bolometer are two orders of magnitude more stringent than those for a thermopile detector. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Foote, MC (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 10 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 0-8194-3172-9 J9 P SOC PHOTO-OPT INS PY 1999 VL 3698 BP 344 EP 350 DI 10.1117/12.354536 PG 7 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BN59F UT WOS:000082322000037 ER PT S AU Gunapala, SD Bandara, SV Singh, A Liu, JK Rafol, SB Luong, EM Mumolo, JM Tran, NQ Vincent, JD Shott, CA Long, J LeVan, PD AF Gunapala, SD Bandara, SV Singh, A Liu, JK Rafol, SB Luong, EM Mumolo, JM Tran, NQ Vincent, JD Shott, CA Long, J LeVan, PD BE Andresen, BF Scholl, MS TI 8-9 and 14-15 mu m two-color 640x486 GaAs/AlGaAs Quantum Well Infrared Photodetector (QWIP) focal plane array camera SO INFRARED TECHNOLOGY AND APPLICATIONS XXV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Infrared Technology and Applications XXV Conference CY APR 05-09, 1999 CL ORLANDO, FL SP SPIE ID FABRICATION; PERFORMANCE; DETECTORS AB An optimized long-wavelength two-color Quantum Well Infrared Photodetector (QWIP) device structure has been designed. This device structure was grown on a three-inch semi-insulating GaAs substrate by molecular beam epitaxy (MBE). This wafer was processed into several 640x486 format monolithically integrated 8-9 and 14-15 mu m two-color (or dual wavelength) QWIP focal plane arrays (FPAs). These FPAs were then hybridized to 640x486 silicon CMOS readout multiplexers. A thinned (i.e., substrate removed) FPA hybrid was integrated into a liquid helium cooled dewar to perform electrical and optical characterization and to demonstrate simultaneous two-color imagery. The 8-9 mu m detectors in the FPA have shown background limited performance (BLIP) at 70 K operating temperature, at 300 K background with f/2 cold stop. The 14-15 mu m detectors of the FPA have reached BLIP at 40 K operating temperature at the same background conditions. In this paper we discuss the performance of this long-wavelength dualband QWIP FPA in quantum efficiency, detectivity, noise equivalent temperature difference (NE Delta T), uniformity, and operability. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 15 TC 40 Z9 40 U1 0 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3172-9 J9 P SOC PHOTO-OPT INS PY 1999 VL 3698 BP 687 EP 697 DI 10.1117/12.354502 PG 11 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BN59F UT WOS:000082322000073 ER PT S AU Lin, SC Wilkins, R Nersesyan, M Luss, D AF Lin, SC Wilkins, R Nersesyan, M Luss, D BE Bansal, NP Singh, JP TI Combustion synthesis of Cd-In-Ga-O powder for novel thin film growth substrate SO INNOVATIVE PROCESSING AND SYNTHESIS OF CERAMICS, GLASSES, AND COMPOSITES II SE CERAMIC TRANSACTIONS LA English DT Proceedings Paper CT 100th Annual Meeting of the American-Ceramic-Society CY MAY 03-06, 1998 CL CINCINNATI, OH SP Amer Ceram Soc ID HIGH-TEMPERATURE SYNTHESIS; DEFECTS; LIGAO2 AB Self-propagating High-temperature Synthesis (SHS) method was used for producing CdIn1.673Ga0.327O4 complex oxide, a potential substrate for growing GaN thin film. The SHS process was conducted using two initial mixtures, CdIn2O3-Ga2O3, and Cd-In-Ga2O3 reaching combustion temperatures 837 degrees C and 1,400 degrees C, respectively. The combination of these mixtures enabled us to carry out the synthesis below the sublimation temperature of the desired product (approximate to 1,100 degrees C) and to increase its yield. Post-treatment increased the homogeneity of the product. C1 Prairie View A&M Univ, NASA, Ctr Appl Radiat Res, Prairie View, TX 77446 USA. RP Lin, SC (reprint author), Prairie View A&M Univ, NASA, Ctr Appl Radiat Res, Prairie View, TX 77446 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 1042-1122 BN 1-57498-060-2 J9 CERAM TRANS PY 1999 VL 94 BP 23 EP 33 PG 11 WC Materials Science, Ceramics; Materials Science, Composites SC Materials Science GA BN02S UT WOS:000080430700003 ER PT S AU Bhatt, RT Palczer, AR AF Bhatt, RT Palczer, AR BE Bansal, NP Singh, JP TI Surface area, and oxidation effects on nitridation kinetics of silicon powder compacts SO INNOVATIVE PROCESSING AND SYNTHESIS OF CERAMICS, GLASSES, AND COMPOSITES II SE CERAMIC TRANSACTIONS LA English DT Proceedings Paper CT 100th Annual Meeting of the American-Ceramic-Society CY MAY 03-06, 1998 CL CINCINNATI, OH SP Amer Ceram Soc AB Commercially available silicon powders were wet-attrition-milled from 2 to 48 hr to achieve surface areas (SA's) ranging from 1.3 to 70 m(2)/g. The surface area effects on the nitridation kinetics of silicon powder compacts were determined at 1250 or 1350 degrees C for 4 hr. In addition, the influence of nitridation environment, and preoxidation on nitridation kinetics of a silicon powder of high surface area (approximate to 63 m(2)/g) was investigated. As the surface area increased, so did the percentage nitridation after 4 hr in N-2 at 1250 or 1350 degrees C. Silicon powders of high surface area (>40 m(2)/g) can be nitrided to > 70% at 1250 degrees C in 4 hr. The nitridation kinetics of the high-surface-area powder compacts were significantly delayed by preoxidation treatment. Conversely, the nitridation environment had no significant influence on the nitridation kinetics of the same powder. Impurities present in the starting powder, and those accumulated during attrition milling, appeared to react with the silica layer on the surface of silicon particles to form a molten silicate layer, which provided a path for rapid diffusion of nitrogen and enhanced the nitridation kinetics of high surface area silicon powder. C1 USA, Lewis Res Ctr, Res Lab, Cleveland, OH 44135 USA. RP Bhatt, RT (reprint author), USA, Lewis Res Ctr, Res Lab, 21000 Brook Pk Rd, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 1042-1122 BN 1-57498-060-2 J9 CERAM TRANS PY 1999 VL 94 BP 549 EP 560 PG 12 WC Materials Science, Ceramics; Materials Science, Composites SC Materials Science GA BN02S UT WOS:000080430700049 ER PT S AU Yendler, B AF Yendler, B BE Tamponnet, C TI Preliminary evaluation of soil moisture probe for use with arcillite SO INSTRUMENTATION FOR MONITORING AND CONTROL IN CELSS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.7 Symposium of COSPAR Sciencific Commission F at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res AB There is a need for reliable methods of measuring the level and distribution of water in the solid substrates that are used for growing plants in space. In a microgravity environment, water distribution is governed generally by capillary forces. Arcillite is the solid substrate used in the ASTROCULTURE(TM) system which was developed for growing plants in spacer The goal of this study is to evaluate the applicability of heat pulse moisture sensors for measuring moisture levels in Arcillite. The ASTROCULTURE system uses suction as a means of controlling the moisture level in Arcillite, but the spatial distribution of the moisture is left unknown. Studies of the moisture content in a cell experiment were conducted to calibrate a heat pulse moisture sensor and then the sensor was used in a suction experiment to verify moisture content and distribution. Results of the studies demonstrate that head pulse moisture sensors can be used to monitor moisture content and distribution within the root module of the ASTROCULTURE system. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Ames Res Ctr, Lockheed Martin Engn & Sci Co, Moffett Field, CA 94035 USA. RP Yendler, B (reprint author), NASA, Ames Res Ctr, Lockheed Martin Engn & Sci Co, Mail Stop 239-23, Moffett Field, CA 94035 USA. NR 5 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 0-08-043588-2 J9 ADV SPACE RES PY 1999 VL 22 IS 10 BP 1419 EP 1423 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Instruments & Instrumentation; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Instruments & Instrumentation; Meteorology & Atmospheric Sciences GA BM68L UT WOS:000079454700004 ER PT S AU Blackwell, C AF Blackwell, C BE Tamponnet, C TI Effective speed-up of slowly responding measurement systems SO INSTRUMENTATION FOR MONITORING AND CONTROL IN CELSS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.7 Symposium of COSPAR Sciencific Commission F at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res AB In some applications, the slow response of measurement systems can present significant control problems or cause difficulties in interpreting data sequences, even though they are quite accurate in indicating the value of an unchanging measured parameter. Happily, instrument systems often have characteristics which make it possible to apply certain advanced systems control techniques which can compensate for the inherent slowness of the instrument system. In this paper, some means of dealing with this problem in some scenarios are described. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Blackwell, C (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043588-2 J9 ADV SPACE RES PY 1999 VL 22 IS 10 BP 1437 EP 1441 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Instruments & Instrumentation; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Instruments & Instrumentation; Meteorology & Atmospheric Sciences GA BM68L UT WOS:000079454700006 ER PT S AU Soffen, G AF Soffen, G BE Hoover, RB TI Life is everywhere? SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology II CY JUL 20-22, 1999 CL DENVER, CO SP SPIE DE extraterrestrial life; cosmos; biogenesis; life detection; optical microscopy; microbiology; microfossils; Mars; space missions AB The question of the existence of extraterrestrial life is of great scientific interest. Presently we have knowledge of life only on the Earth that appears to have a single and unique biogenesis. Arguments are made that it is more likely that the living process exists throughout the cosmos, than that the Earth is the only inhabited planet. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Soffen, G (reprint author), NASA, Goddard Space Flight Ctr, 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 0-8194-3241-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3755 BP 2 EP 7 DI 10.1117/12.375083 PG 6 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BP48Y UT WOS:000085289800001 ER PT S AU Yu, W AF Yu, W BE Hoover, RB TI Microscope-on-chip using micro-channel and solid state image sensors SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology II CY JUL 20-22, 1999 CL DENVER, CO SP SPIE DE microscope; micro-channel; image sensor; optical microscope AB Recently, Jet Propulsion Laboratory has invented and developed a miniature optical microscope, microscope-on-chip using micro-channel and solid state image sensors. It is lightweight, low-power, fast speed instrument, it has no image lens, does not need focus adjustment, and the total mass is less than 100g. A prototype has been built and demonstrated at JPL. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yu, W (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 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 0-8194-3241-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3755 BP 33 EP 36 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BP48Y UT WOS:000085289800004 ER PT S AU Hoover, RB AF Hoover, RB BE Hoover, RB TI Astrobiological significance of microorganisms in permafrost and ice SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology II CY JUL 20-22, 1999 CL DENVER, CO SP SPIE ID CRYOCONITE HOLES; ALGAL MATS; REMOVAL; EARTH; SPACE; LAKES AB Microorganisms of the permafrost, glaciers, and polar ice sheets of planet Earth provide analogs for microbial life forms that may be encountered in ice or permafrost of Mars, Europa, Callisto, Ganymede, or even asteroids or comets. Most bodies of our Solar System are frozen worlds. The microbiota of the terrestrial cryosphere help establish the thermal and temporal limitations of life on Earth and provide clues to of where and how we should search for evidence of life elsewhere in the Cosmos. Consequently, these life forms are relevant to Astrobiology. Cryopreserved microorganisms can remain viable (in deep anabiosis) in permafrost and ice for millions of years and may contain intact ancient DNA, lipids, enzymes, proteins and genes. Some microorganisms carry out metabolic processes in water films and brine, acidic, or alkaline channels in permafrost or ice at temperatures far below OC. Complex microbial ecosystems may inhabit snow, ice-bubbles, and cryoconite holes on glaciers and the polar caps. At the NASA Marshall Space Flight Center we employed the Environmental Scanning Electron Microscope to study the morphology, ultra-microstructure and chemical composition of microorganisms in-situ in ancient permafrost and ice. In this paper we present images of cryopreserved microorganisms from deep ice cores above Lake Vostok and thermokarst ponds of the Fox Tunnel of Alaska. C1 NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Hoover, RB (reprint author), NASA, George C Marshall Space Flight Ctr, Dept Space Sci, SD50, Huntsville, AL 35812 USA. NR 27 TC 2 Z9 2 U1 2 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3241-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3755 BP 59 EP 71 DI 10.1117/12.375087 PG 13 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BP48Y UT WOS:000085289800007 ER PT S AU Hoover, RB Rozanov, AY AF Hoover, RB Rozanov, AY BE Hoover, RB TI Biomorphic structures in Mighei carbonaceous chondrite SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology II CY JUL 20-22, 1999 CL DENVER, CO SP SPIE C1 NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Hoover, RB (reprint author), NASA, George C Marshall Space Flight Ctr, Dept Space Sci, ES82, Huntsville, AL 35812 USA. NR 9 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 0-8194-3241-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3755 BP 120 EP 127 DI 10.1117/12.375070 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BP48Y UT WOS:000085289800013 ER PT S AU Hoover, RB Abyzov, SS Ivanov, MV AF Hoover, RB Abyzov, SS Ivanov, MV BE Hoover, RB TI Environmental Scanning Electron Microscopy investigations of ancient microorganisms from deep ice above Lake Vostok SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology II CY JUL 20-22, 1999 CL DENVER, CO SP SPIE AB Extensive microbiological studies carried out at Vostok Station, Antarctica over the past several years have revealed a complex assemblage of well preserved microbial cells. The Antarctic ice sheet provides an ideal model for the investigation of the types of microbial forms and the state of preservation that may be expected after long term preservation in ice. The diversity of forms that are present in the Vostok core material is very great with many different taxonomic groups are represented in the ice sheet horizons above 300000 years. The microorganisms encountered include diatoms and other algae, cyanobacteria, bacteria and bacterial spores, fungi, yeasts, actinomycetes, and plant pollen. The microorganisms of the Earth's polar ice sheets provide analogs for microbiota that might be encountered in the polar ice sheets and glaciers of Mars, and the ice of comets or frozen moons such as Europa, Callisto, Ganymede, and Miranda. Since most bodies of our Solar System are frozen worlds, the microbial life of the terrestrial cryosphere is extremely important to Astrobiology. These microorganisms help establish the thermal and temporal limitations of life on Earth. The ice microbiota help define how and where we should look for signatures of life elsewhere, and they may hold clues to the distribution of life in the Cosmos. Some microorganisms can remain viable for geological periods frozen in ice. We have used the Environmental Scanning Electron Microscope at the NASA Marshall Space Flight Center to investigate the ultra-microstructure, morphology, and chemical composition of cryopreserved microorganisms from deep ice cores just above Lake Vostok in Antarctica and a database of images has been generated. C1 NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Hoover, RB (reprint author), NASA, George C Marshall Space Flight Ctr, Dept Space Sci, SD50, Huntsville, AL 35812 USA. NR 13 TC 1 Z9 1 U1 1 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 0-8194-3241-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3755 BP 187 EP 197 DI 10.1117/12.375076 PG 11 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BP48Y UT WOS:000085289800018 ER PT S AU Richmond, RC Sridhar, R Zhou, Y Daly, MJ AF Richmond, RC Sridhar, R Zhou, Y Daly, MJ BE Hoover, RB TI Physico-chemical survival pattern for the radiophile D-radiodurans: A polyextremophile model for life on Mars SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology II CY JUL 20-22, 1999 CL DENVER, CO SP SPIE ID DOUBLE-STRAND BREAKS; DEINOCOCCUS-RADIODURANS; RADIATION-RESISTANT; MICROCOCCUS-RADIODURANS; PERMAFROST; HYPOTHESIS; INDUCTION; DEUTERIUM; GLYCEROL; ALH84001 C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Richmond, RC (reprint author), NASA, George C Marshall Space Flight Ctr, SD48, Huntsville, AL 35812 USA. NR 53 TC 11 Z9 11 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 0-8194-3241-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3755 BP 210 EP 222 DI 10.1117/12.375078 PG 13 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BP48Y UT WOS:000085289800020 ER PT J AU MacLeod, TC Ho, FD AF MacLeod, TC Ho, FD TI Integrating partial polarization into a Metal-Ferroelectric-Semiconductor Field Effect Transistor model SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 11TH International Symposium on Integrated Ferroelectrics CY MAR 07-10, 1999 CL COLORADO SPRINGS, COLORADO DE ferroelectric transistors; partial polarization AB The ferroelectric channel in a Metal-Ferroelectric-Semiconductor Field Effect Transistor (MFSFET) can partially change its polarization when the gate voltage nears the polarization threshold voltage as shown by Aizawa([1]). This causes the MFSFET Drain current to change with repeated pulses of the same gate voltage near the polarization threshold voltage. A previously developed model [2] assumed that for a given gate voltage and channel polarization, a single Drain current value would be generated. The earlier model accurately predicts the Drain current given a series of increasing and decreasing pulses, but does not predict the current well for a series of random pulses. A study has been done to characterize the effects of partial polarization on the Drain current of a MFSFET. These effects have been incorporated into a more comprehensive mathematical model of the MFSFET. The model takes into account the hysteresis nature of the MFSFET and the time dependent decay as well as the effects of partial polarization. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. RP MacLeod, TC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 4 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 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 1999 VL 27 IS 1-4 BP 1137 EP 1145 PG 9 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 290RU UT WOS:000085692300011 ER PT J AU Miranda, FA Van Keuls, FW Subramanyam, G Mueller, CH Romanofsky, RR Rosado, G AF Miranda, FA Van Keuls, FW Subramanyam, G Mueller, CH Romanofsky, RR Rosado, G TI Correlation between material properties of ferroelectric thin films and design parameters for microwave device applications: Modeling examples and experimental verification SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 11TH International Symposium on Integrated Ferroelectrics CY MAR 07-10, 1999 CL COLORADO SPRINGS, COLORADO DE ferroelectric films; tunable microwave components; microstripline configuration; characteristic impedance; effective dielectric constant; attenuation; SrTiO3; BaxSr1-xTiO3; LaAlO3; 10-20 GHz AB The application of thin ferroelectric films for frequency and phase agile components is the topic of interest of many research groups worldwide. Consequently, proof-of-concepts (POC) of different tunable microwave components using either (HTS, metal)/ferroelectric thin film/dielectric heterostructures or (thick, thin) film "flip-chip" technology have been reported. Either as ferroelectric thin film characterization tools or from the point of view of circuit implementation approach, both configurations have their respective advantages and limitations. However, we believe that because of the progress made so far using the heterostructure (i.e., multilayer) approach, and due to its intrinsic features such as planar configuration and monolithic integration, a study on the correlation of circuit geometry aspects and ferroelectric material properties could accelerate the insertion of this technology into working systems. In this paper, we will discuss our study performed on circuits based on microstrip lines at frequencies above 10 GHz, where the multilayer configuration offers greater ease of insertion due to circuit's size reduction. Modeled results of relevant circuit parameters such as the characteristic impedance, effective dielectric constant, and attenuation as a function of ferroelectric film's dielectric constant, tan delta, and thickness, will be presented for SrTiO3 and BaxSr1-xTiO3 ferroelectric films. A comparison between the modeled and experimental data for some of these parameters will be presented. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Univ Dayton, Dayton, OH 45469 USA. Univ Puerto Rico, Humacao, PR 00791 USA. RP Miranda, FA (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 1 Z9 1 U1 1 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 1999 VL 24 IS 1-4 BP 195 EP 214 DI 10.1080/10584589908215592 PG 20 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 290KD UT WOS:000085674700021 ER PT J AU Subramanyam, G Van Keuls, FW Miranda, FA Canedy, CL Aggarwal, S Venkatesan, T Ramesh, R AF Subramanyam, G Van Keuls, FW Miranda, FA Canedy, CL Aggarwal, S Venkatesan, T Ramesh, R TI Correlation of electric field and critical design parameters for ferroelectric tunable microwave filters SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 11TH International Symposium on Integrated Ferroelectrics CY MAR 07-10, 1999 CL COLORADO SPRINGS, COLORADO DE ferroelectric thin-films; microwave frequencies; microstrip lines; tunable bandpass filters AB The correlation of electric field and critical design parameters such as the insertion loss, frequency tunability, return loss, and bandwidth of conductor/ferroelectric/dielectric microstrip tunable K-band microwave filters is discussed in this work. This work is based primarily on barium strontium titanate (BSTO) ferroelectric thin film based tunable microstrip filters for room temperature applications. Two new parameters which we believe will simplify the evaluation of ferroelectric thin films for tunable microwave filters, are defined. The first of these, called the sensitivity parameter, is defined as the incremental change in center frequency with incremental change in maximum applied electric field (E (PEAK)) in the filter. The other, the loss parameter, is defined as the incremental or decremental change in insertion loss of the filter with incremental change in maximum applied electric field. At room temperature, the Au/BSTO/LAO microstrip filters exhibited a sensitivity parameter value between 15 and 5 MHz/cm/kV. The loss parameter varied for different bias configurations used for electrically tuning the filter. The loss parameter varied from 0.05 to 0.01 dB/cm/kV at room temperature. C1 Univ Dayton, Dayton, OH 45469 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Univ Maryland, College Pk, MD 20742 USA. RP Subramanyam, G (reprint author), Univ Dayton, Dayton, OH 45469 USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 10 TC 14 Z9 14 U1 3 U2 6 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 1999 VL 24 IS 1-4 BP 273 EP 285 DI 10.1080/10584589908215597 PG 13 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 290KD UT WOS:000085674700026 ER PT S AU Georgeff, M Pell, B Pollack, M Tambe, M Wooldridge, M AF Georgeff, M Pell, B Pollack, M Tambe, M Wooldridge, M BE Muller, JP Singh, MP Rao, AS TI The belief-desire-intention model of agency SO INTELLIGENT AGENTS V: AGENT THEORIES, ARCHITECTURES, AND LANGUAGES SE LECTURE NOTES IN ARTIFICIAL INTELLIGENCE LA English DT Article; Proceedings Paper CT 5th International Workshop on Agent Theories, Architectures, and Languages (ATAL 98) CY JUL 04-07, 1998 CL PARIS, FRANCE C1 Australian AI Inst, Melbourne, Vic 3000, Australia. NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. Univ Pittsburgh, Dept Comp Sci, Intelligent Syst Program, Pittsburgh, PA 15260 USA. Univ So Calif, Dept Comp Sci, ISI, Marina Del Rey, CA 90292 USA. Univ London Queen Mary & Westfield Coll, Dept Elect Engn, London E1 4NS, England. RP Georgeff, M (reprint author), Australian AI Inst, Level 6,171 Trobe St, Melbourne, Vic 3000, Australia. RI Wooldridge, Michael/A-1329-2012 NR 18 TC 57 Z9 58 U1 1 U2 2 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65713-4 J9 LECT NOTES ARTIF INT PY 1999 VL 1555 BP 1 EP 10 PG 10 WC Computer Science, Artificial Intelligence SC Computer Science GA BP13B UT WOS:000084208600001 ER PT B AU Cooper, BA Hange, DW Mikulic, JJ AF Cooper, BA Hange, DW Mikulic, JJ BE Cuschieri, J Glegg, S Yong, Y TI Engineered solutions to reduce occupational noise exposure at the NASA Glenn Research Center: A five-year progress summary (1994-1999) SO INTER-NOISE 99: PROCEEDINGS OF THE 1999 INTERNATIONAL CONGRESS ON NOISE CONTROL ENGINEERING, VOLS 1-3 LA English DT Proceedings Paper CT International Congress on Noise Control Engineering CY DEC 06-08, 1999 CL FT LAUDERDALE, FL SP Int Inst Noise Control Engn, Inst Noise Control Engn USA C1 NASA, John H Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Cooper, BA (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU INST NOISE CONTROL ENGINEERING PI POUGHKEEPSIE PA PO BOX 3206, ARLINGTON BRANCH, POUGHKEEPSIE, NY 12603 USA BN 0-9622072-3-3 PY 1999 BP 1069 EP 1074 PG 4 WC Acoustics SC Acoustics GA BR05W UT WOS:000165528400200 ER PT B AU Grosveld, FW AF Grosveld, FW BE Cuschieri, J Glegg, S Yong, Y TI Calibration of the Structural Acoustics Loads and Transmission facility at NASA Langley Research Center SO INTER-NOISE 99: PROCEEDINGS OF THE 1999 INTERNATIONAL CONGRESS ON NOISE CONTROL ENGINEERING, VOLS 1-3 LA English DT Proceedings Paper CT International Congress on Noise Control Engineering CY DEC 06-08, 1999 CL FT LAUDERDALE, FL SP Int Inst Noise Control Engn, Inst Noise Control Engn USA C1 NASA, Langley Res Ctr, Lockheed Martin Engn & Sci Co, Hampton, VA 23681 USA. RP Grosveld, FW (reprint author), NASA, Langley Res Ctr, Lockheed Martin Engn & Sci Co, Mail Stop 463, Hampton, VA 23681 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU INST NOISE CONTROL ENGINEERING PI POUGHKEEPSIE PA PO BOX 3206, ARLINGTON BRANCH, POUGHKEEPSIE, NY 12603 USA BN 0-9622072-3-3 PY 1999 BP 1541 EP 1546 PG 6 WC Acoustics SC Acoustics GA BR05W UT WOS:000165528400289 ER PT S AU Desch, MD Ogilvie, KW Franz, H AF Desch, MD Ogilvie, KW Franz, H BE Sibeck, DG Kudela, K TI The WIND program: 1998-2000 SO INTERBALL IN THE ISTP PROGRAM: STUDIES OF THE SOLAR WIND-MAGNETOSPHERE-IONOSPHERE INTERACTION SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Coordinated Studies of the Solar Wind-Magnetosphere-Ionosphere Interaction - Interball Observations CY SEP 07-11, 1998 CL TECH UNIV, KOSICE, SLOVAKIA SP Tech Univ, Fac Elect Engn & Informat, P J Safarik Univ, Fac Sci, Slovak Acad Sci, Inst Exptl Phys, Charles Univ, Fac Math & Phys, NATO Sci Affairs Div HO TECH UNIV ID MAGNETIC CLOUD; GEOTAIL C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Desch, MD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Franz, Heather/F-3508-2012 NR 16 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-5863-5 J9 NATO ADV SCI I C-MAT PY 1999 VL 537 BP 29 EP 39 PG 11 WC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences GA BP44J UT WOS:000085158600003 ER PT S AU Kessel, RL Chen, SH AF Kessel, RL Chen, SH BE Sibeck, DG Kudela, K TI On the Earth's bow shock near solar minimum SO INTERBALL IN THE ISTP PROGRAM: STUDIES OF THE SOLAR WIND-MAGNETOSPHERE-IONOSPHERE INTERACTION SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Coordinated Studies of the Solar Wind-Magnetosphere-Ionosphere Interaction - Interball Observations CY SEP 07-11, 1998 CL TECH UNIV, KOSICE, SLOVAKIA SP Tech Univ, Fac Elect Engn & Informat, P J Safarik Univ, Fac Sci, Slovak Acad Sci, Inst Exptl Phys, Charles Univ, Fac Math & Phys, NATO Sci Affairs Div HO TECH UNIV ID WIND C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kessel, RL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-5863-5 J9 NATO ADV SCI I C-MAT PY 1999 VL 537 BP 87 EP 102 PG 16 WC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences GA BP44J UT WOS:000085158600007 ER PT S AU Szabo, A Lepping, RP Larson, DE AF Szabo, A Lepping, RP Larson, DE BE Sibeck, DG Kudela, K TI Crossing the heliospheric current sheet SO INTERBALL IN THE ISTP PROGRAM: STUDIES OF THE SOLAR WIND-MAGNETOSPHERE-IONOSPHERE INTERACTION SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Coordinated Studies of the Solar Wind-Magnetosphere-Ionosphere Interaction - Interball Observations CY SEP 07-11, 1998 CL TECH UNIV, KOSICE, SLOVAKIA SP Tech Univ, Fac Elect Engn & Informat, P J Safarik Univ, Fac Sci, Slovak Acad Sci, Inst Exptl Phys, Charles Univ, Fac Math & Phys, NATO Sci Affairs Div HO TECH UNIV ID INTERPLANETARY MAGNETIC-FIELD; PLANETARY SECTOR BOUNDARIES; ELECTRONS; CLOUDS; PLASMA AB The heliospheric current sheet (HCS), the largest coherent structure in the heliosphere, is a wavy surface separating the two opposite magnetic polarity hemispheres of the heliosphere. Joint WIND magnetic field and electron observations near solar minimum conditions and far away from the Earth's bow shock reveal that while sector boundary crossings are usually marked by many, up to dozens of large field directional discontinuities, in most cases only one of them is a true sector polarity reversal and, hence, a bona fide crossing of the global HCS. Though a number of multiple HCS Crossings were identified along with magnetic cloud occlusions, most observations during our analysis interval are consistent with a single HCS surface with significant magnetic field kinks nearby it. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Szabo, A (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-5863-5 J9 NATO ADV SCI I C-MAT PY 1999 VL 537 BP 231 EP 237 PG 7 WC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences GA BP44J UT WOS:000085158600017 ER PT B AU Mandutianu, S Stoica, A AF Mandutianu, S Stoica, A BE Arabnia, HR TI An evolvable multi-agent approach to space operations engineering SO INTERNATIONAL CONFERENCE ON ARTIFICIAL INTELLIGENCE, VOL I AND II LA English DT Proceedings Paper CT 1999 International Conference on Artificial Intelligence (ICAI 99) CY JUN 28-JUL 01, 1999 CL LAS VEGAS, NV SP Comp Sci Res, Eudc & Applicat Press, Comp Vis Res & Applicat Tech, Int Assoc Math & Comp Simulat, Int Technol Inst, Korea Info Proc Soc, Natl Super Comp Ctr Enery & Environm, Las Vegas, Dept Energy, Sundance Digital Signal Proc, Inc, World Sci & Engn Soc AB A complex system of spacecraft and ground tracking stations, as well as a constellation of satellites or spacecraft, has to be able to reliably withstand sudden environment changes, resource fluctuations, dynamic resource configuration, limited communication bandwidth, etc., while maintaining the consistency of the system as a whole. It is not known in advance when a change in the environment might occur or when a particular exchange will happen. A higher degree of sophistication for the communication mechanisms between different parts of the system is required. The actual behavior has to be determined while the system is performing and the course of action can be decided at the individual level. Under such circumstances, the solution will highly benefit from increased on-board and on the ground adaptability and autonomy. An evolvable architecture based on intelligent agents that communicate and cooperate with each other can offer advantages in this direction. This paper presents an architecture of an evolvable agent-based system (software and software/hardware hybrids) as well as some plans for further implementation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mandutianu, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 161-260, Pasadena, CA 91109 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU C S R E A PRESS PI ATHENS PA 115 AVALON DR, ATHENS, GA 30606 USA BN 1-892512-18-1 PY 1999 BP 598 EP 604 PG 7 WC Computer Science, Artificial Intelligence SC Computer Science GA BN96N UT WOS:000083679100097 ER PT B AU Chien, CH Lyon, RG Murphy, TP AF Chien, CH Lyon, RG Murphy, TP BE Arabnia, HR TI Parallelization of the optical system modeling package SO INTERNATIONAL CONFERENCE ON PARALLEL AND DISTRIBUTED PROCESSING TECHNIQUES AND APPLICATIONS, VOL VI, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA 99) CY JUN 28-JUL 01, 1999 CL LAS VEGAS, NV SP Comp Sci Res Educ & Applicat Press, Comp Vis Res & Applicat Tech, Int Assoc Math & Comp Simulat, Int Technol Inst, Java High Performance Comp Res Grp, Korea Informat Processing Soc, US DOE, Natl Supercomp Ctr Energy & Environm Las Vegas, Sundance Digital Signal Processing Inc, World Sci & Engn Soc DE space telescope; optical sensors; parallel FFT; estimation functions ID SPREAD AB PMOD is an optical Point spread function MODeling code initially developed for modeling the Hubble Space Telescope [1, 2]. The code was previously ported from a NASA/Goddard Space Flight Center (GSFC) Gray YMP to a MasPar MP2 (circa 1995). It is currently being ported to NASA/GSFC's HIVE [3, 4], a 128 processor cluster of Pentium Pros, to be subsequently used for modeling future NASA optical sensors. We analyze the network performance of HIVE with proposed functions and also found in the code conversion the main bottleneck to be a 2D Fast Fourier Transform(FFT) algorithm. Herein, we discuss the PMOD code and conversion to the HIVE architecture with determination of the optimal number of processors for a given 2D FFT size for a specific FFT algorithm [5]. C1 NASA, Goddard Space Flight Ctr, Ctr Excellence Space Data & Informat Sci, Greenbelt, MD 20771 USA. RP Chien, CH (reprint author), NASA, Goddard Space Flight Ctr, Ctr Excellence Space Data & Informat Sci, Code 930-5, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU C S R E A PRESS PI ATHENS PA 115 AVALON DR, ATHENS, GA 30606 USA BN 1-892512-14-9 PY 1999 BP 2941 EP 2946 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BP04U UT WOS:000083968700042 ER PT B AU Cheng, BN Chao, Y Wang, P Bondarenko, M AF Cheng, BN Chao, Y Wang, P Bondarenko, M BE Arabnia, HR TI Climate ocean modeling on a Beowulf class system SO INTERNATIONAL CONFERENCE ON PARALLEL AND DISTRIBUTED PROCESSING TECHNIQUES AND APPLICATIONS, VOLS I-V, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA 99) CY JUN 28-JUL 01, 1999 CL LAS VEGAS, NV SP Comp Sci Res Educ & Applicat Press, Comp Vis Res & Applicat Tech, Int Assoc Math & Comp Simulat, Int Technol Inst, Java High Performance Comp Res Grp, Korea Informat Processing Soc, US DOE, Natl Supercomp Ctr Energy & Environm Las Vegas, Sundance Digital Signal Processing Inc, World Sci & Engn Soc DE Beowulf; cluster computing; ocean modeling; parallel programming AB With the growing power and shrinking cost of personal computers, the availability of fast ethernet interconnections, and public domain software packages, it is now possible to combine them to build desktop parallel computers (named Beowulf or PC clusters) at a fraction of what it would cost to buy systems of comparable pouter from supercomputer companies. This led us to build and assemble our own system, specifically for climate ocean, modeling. In this article, we present our experience with such a system, discuss its network performance, and provide some performance comparison data with both HP SPP2000 and Gray T3E for an ocean model used in present-day oceanographic research. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cheng, BN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU C S R E A PRESS PI ATHENS PA 115 AVALON DR, ATHENS, GA 30606 USA BN 1-892512-15-7 PY 1999 BP 1305 EP 1310 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Mathematics, Applied SC Computer Science; Engineering; Mathematics GA BR81L UT WOS:000167653300193 ER PT J AU Degani, A Shafto, M Kirlik, A AF Degani, A Shafto, M Kirlik, A TI Modes in human-machine systems: Constructs, representation, and classification SO INTERNATIONAL JOURNAL OF AVIATION PSYCHOLOGY LA English DT Article; Proceedings Paper CT 9th International Symposium on Aviation Psychology CY APR 28-MAY 01, 1997 CL COLUMBUS, OHIO ID DEVICES AB This article surveys and discusses human interaction with automated control systems that employ modes. We focus our discussion on the features of the control system that lead to mode confusion and error. We first provide working definitions of the term mode and discuss key constructs that contribute to mode error, such as mode ambiguity and user expectations. Following this, we discuss human interaction with automated control systems in general and cockpit automation in particular. To provide a formal description of human interaction with such control systems, we introduce a modeling language, Statecharts, which is used by system engineers to specify complex control systems. We use the Statecharts language to describe the 3 types of modes that are commonly found in modem control systems: interface, functional, and supervisory modes. Examples from cockpit automation are used to illustrate each type of mode. The article concludes with a brief discussion of the links between the mode constructs and formal representation of human interaction with control systems. C1 San Jose State Univ, San Jose, CA 95192 USA. NASA, Ames Res Ctr, Mt View, CA USA. Georgia Inst Technol, Dept Ind & Syst Engn, Atlanta, GA 30332 USA. RP Degani, A (reprint author), NASA, Ames Res Ctr, MS 262-4,Code IHI, Moffett Field, CA 94035 USA. NR 28 TC 25 Z9 25 U1 1 U2 8 PU LAWRENCE ERLBAUM ASSOC INC PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430-2262 USA SN 1050-8414 J9 INT J AVIAT PSYCHOL JI Int. J. Aviat. Psychol. PY 1999 VL 9 IS 2 BP 125 EP 138 DI 10.1207/s15327108ijap0902_3 PG 14 WC Psychology, Applied SC Psychology GA 181LP UT WOS:000079443100003 ER PT J AU Arian, E Vatsa, VN AF Arian, E Vatsa, VN TI A preconditioning method for shape optimization governed by the Euler equations SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE airfoil optimization; Euler; optimal shape; preconditioning AB We consider a classical aerodynamic shape optimization problem subject to the compressible Euler how equations. The gradient of the cost functional with respect to the shape variables is derived With the adjoint method at the continuous level. The Hessian (second order derivative of the cost functional with respect to the shape variables) is approximated also at the continuous level, as first introduced by Arian and Ta'asan [1]. The approximation of the Hessian is used to approximate the Newton step which is essential to accelerate the numerical solution of the optimization problem. The design space is discretized in the maximum dimension, i.e., the location of each point on the intersection of the computational mesh with the airfoil is taken to be an independent design variable. We give numerical examples for 86 design variables in two different flow speeds and achieve an order of magnitude reduction in the cost functional at a computational effort of a full solution of the analysis partial differential equation (PDE). C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Aerodynam & Acoust Methods Branch, Hampton, VA 23681 USA. RP Arian, E (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. NR 25 TC 4 Z9 5 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1061-8562 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PY 1999 VL 12 IS 1 BP 17 EP 27 DI 10.1080/10618569908940813 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 237AE UT WOS:000082630800002 ER PT J AU Povitsky, A Ofengeim, D AF Povitsky, A Ofengeim, D TI Numerical study of interaction of a vortical density inhomogeneity with shock and expansion waves SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE vortices; unstructured grids; automatic mesh refinement; Euler equations; vortical density inhomogeneity; shock wave; expansion wave ID GAS; VORTEX AB We studied the interaction of a vortical density inhomogeneity (VDI) with shock and expansion waves. We call the VDI the region of concentrated vorticity (vortex) with a density different from that of ambiance. Non-parallel directions of the density gradient normal to the VDI surface and the pressure gradient across a shock wave result in an additional vorticity. The roll-up of the initial round VDI towards a non-symmetrical shape is studied numerically. Numerical modeling of this interaction is performed by a 2-D Euler code. The use of an adaptive unstructured numerical grid makes it possible to obtain high accuracy and capture regions of induced vorticity with a moderate overall number of mesh points. For the validation of the code, the computational results are compared with available experimental results and good agreement is obtained. The interaction of the VDI with a propagating shock wave is studied for a range of initial and induced circulations and obtained flow patterns are presented. The splitting of the VDI develops into the formation of a non-symmetrical vortex pair and not in a set of vortices. A method for the analytical computation of an overall induced circulation Gamma(1) as a result of the interaction of a moving VDI with a number of waves is proposed. Simplified, approximated, expressions for Gamma(1) are derived and their accuracy is discussed. The splitting of the VDI passing through the Prandtl-Meyer expansion wave is studied numerically. The obtained VDI patterns are compared to those for the interaction of the VDI with a propagating shock wave for the same values of initial and induced circulations. These patterns have similar shapes for corresponding time moments. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Univ Manchester, Inst Sci & Technol, Dept Mech Engn, Manchester M60 1QD, Lancs, England. RP Povitsky, A (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1061-8562 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PY 1999 VL 12 IS 2 BP 165 EP 176 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 247CW UT WOS:000083203900005 ER PT J AU Ghanayem, O Stoica, A AF Ghanayem, O Stoica, A TI Fuzzy reasoning using positional information SO INTERNATIONAL JOURNAL OF GENERAL SYSTEMS LA English DT Article DE fuzzy reasoning; alpha-cut; centre of gravity; nonlinear reasoning; power systems stabiliser ID POWER-SYSTEM; CONTROLLER AB The paper argues in favour of reasoning methods that process positional information, i.e. information about the position of the input with respect to the class prototype, and thus achieve a better specification of the corresponding output class. It is shown that such an approach leads to reducing or cancelling unwanted nonlinearities (of input-output characteristic) imposed by reasoning methods, nonlinearities that alter the dependence expressed in the knowledge base. Two methods which use positional information are presented: (a) the mapping of alpha-cut borders (MACB) (Stoica, 1993, Proc. Fifth IFSA World Congress, pp. 1266-1269), inspired from a particular interpretation of the representation theorem and (b) the Left/Right Centre of Gravity (L/R COG) (Ghanayem, 1995, Proc. IEA/AIE, pp. 41-45). The methods are tested in implementing a power system stabiliser (PSS). Simulation results show better performance of methods that use positional information, as compared with classic Mamdani (Mamdani, 1975, International Journal of Man-Machine Studies, 7, 1-13) reasoning. Reflections on a "best" reasoning method conclude the paper. C1 Simoco Pacific Pty Ltd, Raywood Commun, Mulgrave, Vic 3170, Australia. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Ghanayem, O (reprint author), Simoco Pacific Pty Ltd, Raywood Commun, 745 Springvale Rd, Mulgrave, Vic 3170, Australia. EM omarghanayem@hotmail.com NR 17 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 0308-1079 J9 INT J GEN SYST JI Int. J. Gen. Syst. PY 1999 VL 28 IS 2-3 BP 173 EP 199 DI 10.1080/03081079908935234 PG 27 WC Computer Science, Theory & Methods; Ergonomics SC Computer Science; Engineering GA 240RG UT WOS:000082838500005 ER PT J AU Siegel, R AF Siegel, R TI Radiative exchange in a parallel-plate enclosure with translucent protective coatings on its walls SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID THERMAL BARRIER COATINGS AB Thermal barrier and protective coatings are used for reducing temperatures in metal walls in high temperature applications, and for protection in corrosive environments. Radiative transfer is important at elevated temperatures, and hot coated surfaces that view each other can exchange radiation. Radiative exchange calculations are usually for surfaces that are opaque, and each surface has a specific radiating temperature. The analysis must be different when some or all of the surfaces have translucent coatings. Some protective coating materials such as zirconia and alumina, are partially transparent to portions of the thermal radiation spectrum. Hence, the radiative exchange process is more complex since radiation from a coated area depends on the temperatures within its coating. These temperatures are unknown, and they depend on the exchange process. The exchange analyzed here is for a parallel-plate enclosure that can have different heating conditions for the internal and external surfaces of each coated wall. Each wall has an opaque outer layer such as a metal plate, and a translucent coating on the inside. The coatings on opposite walls view each other and exchange radiation. An analytical method is developed for obtaining the temperature distribution in each coating and its opaque substrate. Illustrative results are provided for coatings with Various optical thicknesses, and are compared with results for opaque coatings. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NASA, Lewis Res Ctr, Res & Technol Directorate, Cleveland, OH 44135 USA. RP Siegel, R (reprint author), NASA, Lewis Res Ctr, Res & Technol Directorate, Cleveland, OH 44135 USA. EM robert.siegel@lerc.nasa.gov NR 10 TC 8 Z9 9 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD JAN PY 1999 VL 42 IS 1 BP 73 EP 84 DI 10.1016/S0017-9310(98)00152-5 PG 12 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 144YP UT WOS:000077343700007 ER PT J AU Karasik, BS McGrath, WR AF Karasik, BS McGrath, WR TI Microwave transmission technique for accurate impedance characterization of superconductive bolometric mixers SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE hot-electron bolometer mixer; impedance; mixer bandwidth ID HOT-ELECTRON BOLOMETER; LOW-NOISE; BANDWIDTH; GAIN; THZ AB The impedance of the submillimeter superconducting hot-electron bolometer mixer was measured in the range 0.2-4 GHz. A special technique relying on determination of the S-21 transmission parameter of the device was used. Many advantages of the technique (wide frequency range, in situ calibration, low test power, accuracy) are demonstrated. The estimate of the mixer bandwidth from the impedance data using the mixer theory is in good agreement with the results of the direct bandwidth measurements. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Karasik, BS (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, 1800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Karasik, Boris/C-5918-2011 NR 12 TC 3 Z9 3 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD JAN PY 1999 VL 20 IS 1 BP 21 EP 32 DI 10.1023/A:1021795432650 PG 12 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 158AE UT WOS:000078093200002 ER PT J AU Dorney, DJ Gundy-Burlet, KL Sondak, DL AF Dorney, DJ Gundy-Burlet, KL Sondak, DL TI A survey of hot streak experiments and simulations SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article ID TURBINE STAGE; REDISTRIBUTION AB Experimental and computational data have shown that the flow exiting gas-turbine combustors can contain large circumferential and radial temperature non-uniformities. The temperature non-uniformities, or hot streaks, can have a significant impact on the performance and durability of first-stage turbine airfoils. This paper contains a survey of the hot streak experiments and simulations that have been performed during the last two decades, and the impact they have had on the design of high-pressure turbine stages. C1 Virginia Commonwealth Univ, Dept Engn Mech, Richmond, VA 23284 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Boston Univ, Boston, MA 02215 USA. RP Dorney, DJ (reprint author), Virginia Commonwealth Univ, Dept Engn Mech, 601 W Main St,POB 843015, Richmond, VA 23284 USA. NR 46 TC 16 Z9 20 U1 1 U2 2 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 1999 VL 16 IS 1 BP 1 EP 15 PG 15 WC Engineering, Aerospace SC Engineering GA 196WU UT WOS:000080331500001 ER PT J AU Lepicovsky, J Bruckner, RJ Bencic, TJ Braunscheidel, EP AF Lepicovsky, J Bruckner, RJ Bencic, TJ Braunscheidel, EP TI Modern experimental techniques in turbine engine testing SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article AB The paper describes application of two modem experimental techniques, thin-film thermocouples and pressure sensitive paint, to measurement in turbine engine components. A growing trend of using computational codes in turbomachinery design and development requires experimental techniques to refocus from overall performance testing to acquisition of detailed data on flow and heat transfer physics to validate these codes for design applications. The discussed experimental techniques satisfy this shift in focus. Both techniques are nonintrusive in practical terms. The thin-film thermocouple technique improves accuracy of surface temperature and heat transfer measurements. The pressure sensitive paint technique supplies surface field pressure data rather than discrete point values only. The paper summarizes NASA experience with these techniques and suggests improvements to ease the application of these techniques for future turbomachinery research and code verifications. C1 Dynacs Engn Inc, NASA leRC Grp, Brook Pk, OH 44142 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Lepicovsky, J (reprint author), Dynacs Engn Inc, NASA leRC Grp, Brook Pk, OH 44142 USA. NR 6 TC 1 Z9 1 U1 0 U2 1 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 1999 VL 16 IS 2 BP 61 EP 70 PG 10 WC Engineering, Aerospace SC Engineering GA 244YB UT WOS:000083077400001 ER PT J AU Dorney, DJ Ashpis, DE AF Dorney, DJ Ashpis, DE TI Study of low Reynolds number effects on the losses in low-pressure turbine blade rows SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article ID BOUNDARY-LAYER-TRANSITION; TURBULENCE; SIMULATIONS; SEPARATION; FLOWS AB Experimental data from jet-engine tests have indicated that unsteady blade row interactions land separation can have a significant impact on the efficiency of low-pressure turbine stages. Measured turbine efficiencies at takeoff can be as much as two points higher than those at cruise conditions. Several recent studies have revealed that Reynolds number effects may contribute to the lower efficiencies at cruise conditions. In the current study numerical experiments have been performed to study the models available for low Reynolds number flows, and to quantify the Reynolds number dependence of low-pressure turbine cascades and stages. The predicted aerodynamic results exhibit good agreement with design data. C1 Virginia Commonwealth Univ, Dept Mech Engn, Richmond, VA 23284 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Dorney, DJ (reprint author), Virginia Commonwealth Univ, Dept Mech Engn, 601 W Main St,POB 843015, Richmond, VA 23284 USA. NR 28 TC 2 Z9 2 U1 0 U2 0 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 1999 VL 16 IS 2 BP 91 EP 105 PG 15 WC Engineering, Aerospace SC Engineering GA 244YB UT WOS:000083077400004 ER PT J AU Choy, F Xu, G Polyshchuk, V Zakrajsek, JJ Townsend, DP AF Choy, F Xu, G Polyshchuk, V Zakrajsek, JJ Townsend, DP TI Effect of gear tooth imperfection on dynamics of gear transmission systems SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article ID VIBRATION AB Imperfections in gear teeth often result from errors in the manufacturing process or from material wear during operation. Such imperfections in gear teeth can cause excessive vibrations or even an early failure of the transmission system. This paper examines the effects of gear tooth imperfection on the dynamic characteristics of a gear transmission system. The imperfection of a gear tooth was modeled numerically as the deviation of the gear tooth profile from its ideal, or designed geometry. The resulting changes in gear mesh stiffness due to various profile changes because of wear and damage patterns were evaluated acid incorporated into the global dynamic simulation of the gear transmission system. A parametric study was performed to examine the sensitivity of the system vibration due to gear tooth imperfections. The basic parameters used in this study are the magnitude and geometry of tooth profile changes, the number of consecutive gear teeth damaged, and configuration of the gear system. The results of the global dynamic simulations illustrate the feasibility of using changes in gear mesh stiffness in modeling gear tooth imperfections due to damage and wear. C1 Univ Akron, Dept Mech Engn, Akron, OH 44325 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Choy, F (reprint author), Univ Akron, Dept Mech Engn, Akron, OH 44325 USA. NR 24 TC 2 Z9 2 U1 0 U2 1 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 1999 VL 16 IS 3 BP 161 EP 175 PG 15 WC Engineering, Aerospace SC Engineering GA 247CZ UT WOS:000083204200004 ER PT S AU Mayr, HG Mengel, JG Reddy, CA Chan, KL Porter, HS AF Mayr, HG Mengel, JG Reddy, CA Chan, KL Porter, HS BE Burns, A Killeen, T Rees, D TI The role of gravity waves in maintaining the QBO and SAO at equatorial latitudes SO IONOSPHERIC/THERMOSPHERIC/MESOSPHERIC COUPLING SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C1 1 and C1 2 Symposia of COSPAR Scientific Commission C Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res, Int Union Geodesy & Geophys Int Assoc Geomagnetism & Aeron, Int Union Radio Sci, Sci Comm Solar Terr Phys, Int Union Geodesy & Geophys Int Assoc Meteorol & Atmospher Sci ID DOPPLER-SPREAD PARAMETERIZATION; QUASI-BIENNIAL OSCILLATION; MIDDLE ATMOSPHERE; SEMIANNUAL OSCILLATION; MOMENTUM DEPOSITION; KELVIN WAVE; ZONAL WIND; MODEL; STRATOSPHERE; MESOSPHERE AB We present a numerical spectral model (NSM) that describes the equatorial oscillations in the zonal circulation, the Quasi-biennial Oscillations (QBO) and Semi-annual Oscillations (SAO). The oscillations are generated by the momentum deposition of small scale gravity waves (GW) described with the Doppler spread parameterization (DSP) of I-lines. We discuss here the GW mechanism and some of the conditions that are favorable for generating the QBO and SAG. Our model reproduces the salient features observed and leads to the following conclusions: (1) In 2D, a QBO can be generated with a period of about 30 months, peak amplitude close to 20 m/s near 30 km, and downward propagation velocity of 1.2 km/months, close to the observed values. The QBO phase reverses near 70 km and extends with significant amplitude into the upper mesosphere. (2) SAO amplitudes between 5 and 30 m/s are generated that peak at about 55 km with eastward phase during equinox. A second peak with opposite phase is produced above 70 km. (3) The computed oscillations depend on the rate of radiative cooling and on the chosen eddy viscosity that is tied in the DSP to the GW source but is uncertain to some degree. (4) GW filtering by the QBO at lower altitudes can account for the large variability in the SAO that is observed. The SAO in turn also affects the QBO, and under certain conditions the seasonal (semiannual) variations in the solar forcing can act as a pacemaker to seed and synchronize the QBO. (5) In a 3D version of the model that computes also tides and planetary waves, the amplitudes of the SAG, and even the QBO, are significantly reduced compared to 2D. The tides and planetary waves apparently absorb some of the GW momentum that otherwise in 2D goes into the equatorial oscillations of the zonal circulation. (7) The QBO is also generated in 3D with Kelvin and Rossby gravity waves that deposit momentum through nonlinear advection and radiative cooling. However, the wave amplitudes need to be carefully tuned in order to generate such an oscillation, in contrast to the GW mechanism which is robust. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SM&A Corp, Vienna, VA USA. Vikram Sarabhai Space Ctr, Trivandrum 695022, Kerala, India. Hong Kong Univ Sci & Technol, Hong Kong, Peoples R China. Furman Univ, Greenville, SC 29613 USA. RP Mayr, HG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 35 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 11 BP 1531 EP 1540 DI 10.1016/S0273-1177(99)00876-5 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP27H UT WOS:000084544200019 ER PT S AU Mayr, HG Mengel, JG Chan, KL Porter, HS AF Mayr, HG Mengel, JG Chan, KL Porter, HS BE Burns, A Killeen, T Rees, D TI Seasonal variations and planetary wave modulation of diurnal tides influenced by gravity waves SO IONOSPHERIC/THERMOSPHERIC/MESOSPHERIC COUPLING SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C1 1 and C1 2 Symposia of COSPAR Scientific Commission C Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res, Int Union Geodesy & Geophys Int Assoc Geomagnetism & Aeron, Int Union Radio Sci, Sci Comm Solar Terr Phys, Int Union Geodesy & Geophys Int Assoc Meteorol & Atmospher Sci ID DOPPLER-SPREAD PARAMETERIZATION; LOWER THERMOSPHERE; MIDDLE ATMOSPHERE; MOMENTUM DEPOSITION; SEMIDIURNAL TIDE; PROPAGATING TIDE; MEAN WINDS; SOLAR; MESOSPHERE; LATITUDE AB A nonlinear, 3D, time dependent numerical spectral model (NSM) is discussed, extending from the ground up into the thermosphere. The NSM incorporates the Doppler spread parameterization (DSP) for small scale gravity waves (GW) developed by Hines and is applied in a study of the diurnal tides and the mean zonal circulation, interacting self consistently. Our model results lead to the following conclusions: (1) Due to absorption of GW momentum in the regime of increasing horizontal winds, the amplitude of the fundamental diurnal tide is amplified at altitudes between 80 and 120 km. (2) The semidiurnal ride is also amplified in this way when it is excited without the diurnal tide. With the diurnal tide, however, the amplitude of the semidiurnal tide is reduced. Wave filtering causes strong nonlinear coupling between the two tidal components. (3) The annual variation in the zonal circulation causes GW filtering to produce a strong semiannual variation in the diurnal tide, which is observed on UARS (4) Preliminary results show large seasonal modulations of the semidiurnal tide that appear in part to be caused by GW filtering associated with the seasonal variations in the diurnal tide. (5) The tides are modulated with periods that are related to the planetary waves that are generated by dynamical processes in the mesosphere. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SM&A Corp, Vienna, VA USA. Hong Kong Univ Sci & Technol, Hong Kong, Peoples R China. Furman Univ, Greenville, SC 29613 USA. RP Mayr, HG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. OI Chan, Kwing/0000-0002-6428-1812 NR 26 TC 8 Z9 9 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 11 BP 1541 EP 1544 DI 10.1016/S0273-1177(99)00877-7 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP27H UT WOS:000084544200020 ER PT S AU Biswas, R Das, SK Harvey, D Oliker, L AF Biswas, R Das, SK Harvey, D Oliker, L GP IEEE COMP SOC IEEE COMP SOC TI Portable parallel programming for the dynamic load balancing of unstructured grid applications SO IPPS/SPDP 1999: 13TH INTERNATIONAL PARALLEL PROCESSING SYMPOSIUM & 10TH SYMPOSIUM ON PARALLEL AND DISTRIBUTED PROCESSING, PROCEEDINGS SE INTERNATIONAL PARALLEL PROCESSING SYMPOSIUM. PROCEEDINGS LA English DT Proceedings Paper CT 13th Parallel Processing Symposium / 10th Symposium on Parallel and Distributed Processing (IPPS/SPDP 1999) CY APR 12-16, 1999 CL SAN JUAN, PR SP IEEE Comp Soc, Tech Comm Parallel Proc, ACM SIGARCH ID MESHES; COMPUTATION AB The ability to dynamically adapt an unstructured grid (or mesh) is a powerful tool for solving computational problems with evolving physical features; however, an efficient parallel implementation is rather difficult, particularly from the viewpoint of portability on various multiprocessor platforms. We address this problem by developing PLUM an automatic and architecture-independent framework for adaptive numerical computations in a message-passing environment. Portability is demonstrated by comparing performance on an SP2, an Origin2000, and a T3E, without any code modifications. We also present a general-purpose load balancer that utilizes symmetric broadcast networks (SBN) as the underlying communication pattern, with a goal to providing a global view of system loads across processors. Experiments on an SP2 and an Origin2000 demonstrate the portability of our approach which achieves superb load balance at the cost of minimal extra overhead. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. RP Biswas, R (reprint author), NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. NR 10 TC 6 Z9 6 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 1063-7133 BN 0-7695-0143-5 J9 IPPS PROC PY 1999 BP 338 EP 342 DI 10.1109/IPPS.1999.760497 PG 5 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BM87D UT WOS:000079971800051 ER PT S AU Weisbin, CR Rodriguez, G Schenker, PS Das, H Hayati, SA Baumgartner, ET Maimone, M Nesnas, IA Volpe, RA AF Weisbin, CR Rodriguez, G Schenker, PS Das, H Hayati, SA Baumgartner, ET Maimone, M Nesnas, IA Volpe, RA BE Perry, M TI Autonomous rover technology for Mars sample return SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB Planetary revers enable good sample selection and retrieval for Mars sample return missions. After landing, the revers search for the best possible scientific samples in the region around a lander, and they return these selected samples to an ascent vehicle that launches the samples into Mars orbit. To streamline the search for, the acquisition, and the retrieval of samples, rover autonomy is a critical technology. This paper summarizes a series of experimental results in the evaluation and demonstration of planetary rover autonomy, with a particular emphasis on rover system technology capabilities under development for a 2005 Mars sample return mission and its precursor missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Weisbin, CR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 179-224, Pasadena, CA 91109 USA. NR 16 TC 2 Z9 2 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 1 EP 10 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700001 ER PT S AU Rabideau, G Knight, R Chien, S Fukunaga, A Govindjee, A AF Rabideau, G Knight, R Chien, S Fukunaga, A Govindjee, A BE Perry, M TI Iterative repair planning for spacecraft operations using the ASPEN system SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB This paper describes the Automated Scheduling and Planning Environment (ASPEN). ASPEN encodes complex spacecraft knowledge of operability constraints, flight rules, spacecraft hardware, science experiments and operations procedures to allow for automated generation of low level spacecraft sequences. Using a technique called iterative repair, ASPEN classifies constraint violations (i.e., conflicts) and attempts to repair each by performing a planning or scheduling operation. It must reason about which conflict to resolve first and what repair method to try for the given conflict. ASPEN is currently being utilized in the development of automated planner/scheduler systems for several spacecraft, including the UFO-1 naval communications satellite and the Citizen Explorer (CX1) satellite, as well as for planetary rover operations and antenna ground systems automation. This paper focuses on the algorithm and search strategies employed by ASPEN to resolve spacecraft operations constraints, as well as the data structures for representing these constraints. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rabideau, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 18 TC 4 Z9 4 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 99 EP 106 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700014 ER PT S AU Seraji, H AF Seraji, H BE Perry, M TI Traversability index: A new concept for planetary rovers SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB Traversability Index is introduced in this paper as a new and simple measure for traversability of natural terrains by mobile robots. This index is developed using the framework of fuzzy logic, and is expressed by linguistic fuzzy sets that quantify the suitability of the terrain for traversal based on its physical properties, such as slope and roughness. The Traversability Index; is used for classifying natural terrains, and provides a simple means for incorporating the terrain quality data (out to about 10 meters) into We rover navigation strategy. A set of fuzzy navigation rules is developed using the Traversability Index to guide the rover toward the safest and the most traversable terrain. In addition, another set of fuzzy rules is developed to drive the rover from its initial position to a user-specified goal position. These two rule sets am integrated in a two-stage procedure for autonomous rover navigation without a priori knowledge about the environment. A computer simulation study is presented to demonstrate the capability of the rover to reach the goal safely while avoiding impassable terrains. 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 12 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 159 EP 166 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700022 ER PT S AU Bresina, JL Golden, K Smith, DE Washington, R AF Bresina, JL Golden, K Smith, DE Washington, R BE Perry, M TI Increased flexibility and robustness of Mars rovers SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB Our overall objective is to improve the productivity of Mars revers by increasing the flexibility and robustness of their autonomous behavior. To achieve this objective, we set out to increase the on-board autonomy of revers and enable commanding at a higher level with a more flexible command language. In February, 1999, we demonstrated some of our rover autonomy technologies as part of a Marsokhod rover field test that simulated aspects of the Mars '01-'05 missions. In this paper, we present the commanding language employed in this field test, called the Contingent Rover Language (CRL), and describe the ground tools and on-board executive capabilities that were developed to generate and execute CRL plans. A key feature of CRL is that it enables the encoding of contingent plans specifying what to do if a failure occurs, as well as what to do if a serendipitous science opportunity arises. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bresina, JL (reprint author), NASA, Ames Res Ctr, Mail Stop 269-2, Moffett Field, CA 94035 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 167 EP 173 PG 3 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700023 ER PT S AU Atkinson, DJ AF Atkinson, DJ BE Perry, M TI Autonomy technology challenges of Europa and Titan exploration missions SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB This paper discusses requirements for autonomy technology that arise from the unique attributes of proposed exploration missions to Titan, a moon of Saturn, and Europa, an ice-encrusted moon of Jupiter. Recently, the Project Design Center(1) at NASA Jet Propulsion Laboratory was the focal point for an intensive study of these missions. The mission to Europa tentatively includes a communications station on the surface of the ice, a "cryobot" which will melt through the ice to the ice/water interface, and a "hydrobot" which would freeswim under the water in a scientific search for hydrothermal vents. Autonomous commanding and fault protection technologies are key requirements of this mission, as well as the ability to conduct a science mission with very limited communication to other spacecraft or Earth. The proposed Titan mission includes an "Aerobot", a robotically controlled lighter-than-air vehicle. Part of the mission for the Titan Aerobot includes sampling and scientific analysis of surface materials. Some of the significant drivers of autonomy requirements on a Titan mission include the difficulty in selecting sampling sites, the consequences of long round trip light time delays for commanding, and exogenous events such as weather. Autonomous site selection, commanding, science operations, and robust fault detection, isolation and recovery are a few of the mission critical areas that are discussed in the paper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Atkinson, DJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 126-221, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 175 EP 181 PG 3 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700024 ER PT S AU Fisher, F Estlin, T Mutz, D Chien, S AF Fisher, F Estlin, T Mutz, D Chien, S BE Perry, M TI An AI approach to ground station autonomy for deep space communications SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB This paper describes components of a system for an autonomous deep space tracking station. The system enables fully automated routine operations encompassing scheduling and resource allocation, antenna acid receiver predict generation, track procedure generation from service requests, and closed loop control and error recovery for the station subsystems. This system has been validated by the construction of a prototype Deep Space Terminal (DS-T) tracking station, which has performed a series of demonstrations of autonomous ground station control for downlink services with NASA's Mars Global Surveyor (MGS). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fisher, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 17 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 191 EP 198 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700026 ER PT S AU Parrish, JC AF Parrish, JC BE Perry, M TI The ranger telerobotic shuttle experiment: An on-orbit satellite servicer SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA Special Publications LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands ID SPACE AB The Ranger Telerobotic Shuttle Experiment (RTSX) is a Space Shuttle-based flight experiment to demonstrate key telerobotic technologies for servicing assets in Earth orbit. The flight system will be teleoperated from onboard the Space Shuttle and from a ground control station at the NASA Johnson Space Center. The robot, along with supporting equipment and task elements, will be located in the Shuttle payload bay. A number of relevant servicing operations will be performed-including extravehicular activity (EVA) worksite setup, orbit replaceable unit (ORU) exchange, and other dexterous tasks. The program is underway toward an anticipated launch date in CY2001, and the hardware and software for the flight article and a neutral buoyancy functional equivalent are transitioning from design to manufacture. C1 NASA, Headquarters Off Space Sci, Adv Technol & Miss Studies Div, Washington, DC 20546 USA. RP NASA, Headquarters Off Space Sci, Adv Technol & Miss Studies Div, Mail Code SM, Washington, DC 20546 USA. EM jparrish@hq.nasa.gov NR 10 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 92-9092-760-7 J9 ESA SPEC PUBL PY 1999 VL 440 BP 225 EP 232 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700031 ER PT S AU Yen, J Jain, A Balaram, J AF Yen, J Jain, A Balaram, J BE Perry, M TI ROAMS: Rover analysis, modeling and simulation SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB In this paper, we present the development of ROAMS system for real-time simulation of mobile robotic vehicles. The purpose for the simulation is to provide a virtual testing ground for various subsystems and components of the robotic vehicle, which includes a mechanical subsystem, an electrical subsystem, internal and external sensors, and on-board control software. Using the DARTS/DSHELL framework, the realtime simulator can be applied to both operator-in-the-loop and off-line simulation. This flexibility permits ROAMS to be utilized for various rover tasks in planetary exploration missions, including those of system engineering, scientific research, and operation teams. However, to achieve real-time in the simulation of complex physical systems is non-trivial. Efforts have been made to build the rover model for an efficient and stable simulator. Currently, the rover model is comprised of its mechanical, electrical, and sensor subsystems, all connected with the on-board software. With additional terrain and rock models, we developed a novel solution technique that leads to real-time simulation of the rover traversing Mars-like terrain. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yen, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 249 EP 254 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700034 ER PT S AU Estlin, T Yen, J Petras, R Mutz, D Castano, R Rabideau, G Steele, R Jain, A Chien, S Mjolsness, E Gray, A Mann, T Hayati, S Das, H AF Estlin, T Yen, J Petras, R Mutz, D Castano, R Rabideau, G Steele, R Jain, A Chien, S Mjolsness, E Gray, A Mann, T Hayati, S Das, H BE Perry, M TI An integrated architecture for cooperating rovers SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB This paper presents a rover execution architecture for controlling multiple, cooperating revers. The overall goal of this architecture is to coordinate multiple revers in performing complex tasks for planetary science. This architecture integrates a number of systems and research efforts on single revers and extends them for multiple rover operations. Techniques from a number of different fields are utilized, including AI planning and scheduling, real-time systems and simulation, terrain modeling, and AI machine learning. In this paper, we discuss each architecture component, describe how components interact and present the geological scenario we are using to evaluate the overall architecture. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Estlin, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 19 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 255 EP 262 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700035 ER PT S AU Rajan, K Plaunt, C Pell, B Muscettola, N AF Rajan, K Plaunt, C Pell, B Muscettola, N BE Perry, M TI Integrated planning and execution for satellite telecommunications SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB The next generation of communications satellites may be designed as a fast packet-switched constellation of spacecraft able to withstand substantial bandwidth capacity fluctuation ranging from unstable weather phenomena to intentional jamming of communication. We have designed and partially implemented an architecture for managing satellite telecommunations network resources. Our approach supports advance reservations and dynamic requests, negotiation and fulfilment of prioritized Quality of Service (QoS) contracts, graceful degradation in the presence of dynamic tasks and environmental changes, and optimization of geometrically constrained resources. Our integration of planning and execution to address this task uses planning to avoid resource contentions among requested activities and to configure an independently competent execution system. Our system can be used in routine operations or as a simulation-based design tool. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Rajan, K (reprint author), NASA, Ames Res Ctr, Mail Stop 269-2, Moffett Field, CA 94035 USA. NR 29 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 265 EP 275 PG 7 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700036 ER PT S AU Plaunt, C Jonsson, AK Frank, J AF Plaunt, C Jonsson, AK Frank, J BE Perry, M TI Satellite tele-communications scheduling as dynamic constraint satisfaction SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB We consider a single satellite telecommunications problem in which a dynamic set of calls must be assigned to beams of the satellite. These assignments must satisfy beam-coverage constraints, capacity constraints and requirements based on the priorities of incoming calls; additionally, the satellite must respond quickly to the changing call load and environment. We show how this problem can be solved by using constraint satisfaction technology. We model the problem as a Dynamic Constrained Optimization Problem (DCOP) and present an algorithm inspired by hill-climbing search. We present empirical results from a simulation showing that the algorithm meets the requirements imposed by the problem domain, and finds solutions that are within 2% of the optimal. C1 NASA, Ames Res Ctr, Caelum Res Corp, Moffett Field, CA 94035 USA. RP Plaunt, C (reprint author), NASA, Ames Res Ctr, Caelum Res Corp, Mail Stop 269-2, Moffett Field, CA 94035 USA. NR 9 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 277 EP 284 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700037 ER PT S AU DeCoste, D AF DeCoste, D BE Perry, M TI Adaptive resource profiling SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB This paper addresses the problem of learning resource profiles: upper and lower prediction bounds for engineering resources (e.g. power). We argue for data-driven techniques which specifically learn interval-valued predictions (i.e. best and worst-case bounding functions), as opposed to probabilistic (i.e. soft) predictions. We present and discuss a simple preliminary example using actual data from a rover prototype in a laboratory test-bed environment. We discuss extensions to this work, including integration with an onboard planner that could use these resource profiles, toward improving overall science throughput. C1 CALTECH, Jet Prop Lab, Machine Learning Syst Grp, Pasadena, CA 91109 USA. RP DeCoste, D (reprint author), CALTECH, Jet Prop Lab, Machine Learning Syst Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 285 EP 289 PG 5 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700038 ER PT S AU Barrett, A AF Barrett, A BE Perry, M TI Autonomy architectures for a constellation of spacecraft SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB This paper describes three autonomy architectures for a system that continuously plans to control a fleet of spacecraft using collective mission goals instead of goals or command sequences for each spacecraft. A fleet of self-commanding spacecraft would autonomously coordinate itself to satisfy high level science and engineering goals in a changing partially-understood environment - making feasible the operation of tens or even a hundred spacecraft (such as for interferometer or magnetospheric constellation missions). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Barrett, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 18 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 291 EP 296 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700039 ER PT S AU Maimone, MW Nesnas, IA Das, H AF Maimone, MW Nesnas, IA Das, H BE Perry, M TI Autonomous rock tracking and acquisition from a Mars rover SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB Future Mars exploration missions will perform two types of experiments: science instrument placement for close-up measurement, and sample acquisition for return to Earth. In this paper we describe algorithms we developed for these tasks, and demonstrate them in held experiments using a self-contained Mars Rover prototype, the Rocky 7 rover. Our algorithms perform visual servoing on an elevation map instead of image features, because the latter are subject to abrupt scale changes during the approach. This allows us to compensate for the poor odometry that results from motion on loose terrain. We demonstrate the successful grasp of a 5 cm long rock over Im away using 103-degree field-of-view stereo cameras, and placement of a flexible mast on a rock outcropping over 5m away using 43 degree FOV stereo cameras. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Maimone, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 329 EP 334 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700044 ER PT S AU Ghavimi, AR Serricchio, F Dolgin, B Hadaegh, FY AF Ghavimi, AR Serricchio, F Dolgin, B Hadaegh, FY BE Perry, M TI Autonomous sample acquisition for planetary and small body explorations SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB Robotic drilling and autonomous sample acquisition are considered as the key technology requirements in future planetary or small body exploration missions. Core sampling or subsurface drilling operation is envisioned to be off revers or landers. These supporting platforms are inherently flexible, light, and can withstand only limited amount of reaction forces and torques. This, together with unknown properties of sampled materials, makes the sampling operation a tedious task and quite challenging. This paper highlights the recent advancements in the sample acquisition control system design and development for the in situ scientific exploration of planetary and small interplanetary missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ghavimi, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 335 EP 339 PG 3 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700045 ER PT S AU Tunstel, E AF Tunstel, E BE Perry, M TI Evolution of autonomous self-righting behaviors for articulated nanorovers SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB Miniature rovers with articulated mobility mechanisms are being developed for planetary surface exploration on Mars and small solar system bodies. These vehicles are designed to be capable of autonomous recovery from overturning during surface operations. This paper describes a proposed computational means of developing motion behaviors that achieve the autonomous recovery function. Its aim is to reduce the effort involved in developing self-righting control behaviors. The approach is based on the integration of evolutionary computing with a dynamics simulation environment for evolving and evaluating motion behaviors. The automated behavior design approach is outlined and its underlying genetic programming infrastructure is described. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tunstel, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 107-102, Pasadena, CA 91109 USA. NR 12 TC 6 Z9 6 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 341 EP 346 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700046 ER PT S AU Nayak, PP Bernard, DE Dorais, G Gamble, EB Kanefsky, B Kurien, J Millar, W Muscettola, N Rajan, K Rouquette, N Smith, BD Taylor, W Tung, YW AF Nayak, PP Bernard, DE Dorais, G Gamble, EB Kanefsky, B Kurien, J Millar, W Muscettola, N Rajan, K Rouquette, N Smith, BD Taylor, W Tung, YW BE Perry, M TI Validating the DS1 remote agent experiment SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB This paper describes the validation of the Remote Agent Experiment. A primary goal of this experiment was to provide an onboard demonstration of spacecraft autonomy. This demonstration included both nominal operations with goal-oriented commanding and closed-loop plan execution, and fault protection capabilities with failure diagnosis and recovery, on-board replanning following unrecoverable failures, and system-level fault protection. Other equally important goals of the experiment were to decrease the risk of deploying Remote Agents on future missions and to familiarize the spacecraft engineering community with the Remote Agent approach. These goals were achieved by successfully integrating the Remote Agent with the Deep Space 1 flight software, developing a layered testing approach, and taking various steps to gain the confidence of the spacecraft team. In this paper we describe how we achieved our goals, and discuss the actual on-board demonstration in May, 1999, when the Remote Agent took control of Deep Space 1. C1 NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Nayak, PP (reprint author), NASA, Ames Res Ctr, RIACS, MS 269-2, Moffett Field, CA 94035 USA. NR 8 TC 1 Z9 2 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 349 EP 356 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700047 ER PT S AU Wyatt, J Sherwood, R Sue, M Szijjarto, J AF Wyatt, J Sherwood, R Sue, M Szijjarto, J BE Perry, M TI Flight validation of on-demand operations: The Deep Space One Beacon Monitor Operations Experiment SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB The Beacon Monitor Operations Experiment is one of twelve new technologies currently being flight validated on NASA's Deep Space One mission. The technology enables a spacecraft to routinely indicate the urgency of ground contact using a tone signal rather than telemetry while also summarizing onboard data until a telemetry downlink is required. The two subsystems (tone communication and onboard summarization) have been deployed on DS1 and are in the final stages of flight-testing. The system can be used by missions to lower operational cost and in some instances to decrease mission risk. NASA will see a measurable unburdening of the antenna network if several missions use the technology. This paper provides a description of the technology and shares the results to date. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wyatt, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-270, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 357 EP 362 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700048 ER PT S AU Jonsson, AK Muscettola, N Morris, PH Rajan, K AF Jonsson, AK Muscettola, N Morris, PH Rajan, K BE Perry, M TI Next generation remote agent planner SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands ID SYSTEM AB In May 1999, as part of a unique technology validation experiment onboard the Deep Space One spacecraft, the Remote Agent became the first complete autonomous spacecraft control architecture to run as flight software onboard an active spacecraft. As one of the three components of the architecture, the Remote Agent Planner had the task of laying out the course of action to be taken, which included activities such as turning, thrusting, data gathering, and communicating. Building on the successful approach developed for the Remote Agent Planner, the Next Generation Remote Agent Planner is a completely redesigned and reimplemented version of the planner. The new system provides all the key capabilities of the original planner, while adding functionality, improving performance and providing a modular and extendible implementation. The goal of this ongoing project is to develop a system that provides both a basis for future applications and a framework for further research in the area of autonomous planning for spacecraft. In this article, we present an introductory overview of the Next Generation Remote Agent Planner. We present a new and simplified definition of the planning problem, describe the basics of the planning process, lay out the new system design and examine the functionality of the core reasoning module. C1 NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Jonsson, AK (reprint author), NASA, Ames Res Ctr, RIACS, Mail Stop 269-2, Moffett Field, CA 94035 USA. NR 9 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 363 EP 370 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700049 ER PT S AU Blackmon, T Neveu, C Allport, C Nguyen, L Kline, A Smith, D Anderson, C Gupta, V AF Blackmon, T Neveu, C Allport, C Nguyen, L Kline, A Smith, D Anderson, C Gupta, V BE Perry, M TI Command generation for planetary revers using virtual reality SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands ID TELEROBOTICS AB A system architecture is proposed for command generation of planetary revers through the specification of high-level goals in virtual reality (VR). Through the use of an integrated planning and scheduling system, connected with a high-fidelity simulation model of the rover and its environment, a contingent command sequence could be determined from a set of specified science goals (with given task priorities, constraints, pre-requisites, etc...). As part of NASA's Advanced Technology Program, this paper describes the work in progress towards enabling such a system and the demonstration of the current status for the Marsokhod '99 Field Experiment in the Mojave Dessert. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Blackmon, T (reprint author), NASA, Ames Res Ctr, Mail Stop 269-3, Moffett Field, CA 94035 USA. NR 21 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 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 423 EP 432 PG 8 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700057 ER PT S AU Laubach, SL Olson, CF Burdick, JW Hayati, S AF Laubach, SL Olson, CF Burdick, JW Hayati, S BE Perry, M TI Long range navigation for Mars rovers using sensor-based path planning and visual localisation SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA Special Publications LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB The Mars Pathfinder mission illustrated the benefits of including a mobile robotic explorer on a planetary mission. However, for future Mars rover missions, significantly increased autonomy in navigation is required in order to meet demanding mission criteria. To address these requirements, we have developed new path planning and localisation capabilities that allow a rover to navigate robustly to a distant landmark. These algorithms have been implemented on the JPL Rocky 7 prototype microrover and have been tested extensively in the JPL MarsYard, as well as in natural terrain. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Samad.a.Hayati@jpl.nasa.gov NR 7 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 92-9092-760-7 J9 ESA SPEC PUBL PY 1999 VL 440 BP 455 EP 461 PG 3 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700061 ER PT S AU Ghavimi, AR Serricchio, F Dolgin, B Hadaegh, FY AF Ghavimi, AR Serricchio, F Dolgin, B Hadaegh, FY BE Perry, M TI Autonomous landing and smart anchoring for in-situ exploration of small bodies SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands AB Future NASA missions include in-situ scientific explorations of small interplanetary objects like comets and asteroids. Sample acquisition systems are envisioned to operate directly from the landers that are anchored to the surface. Landing and anchoring proves to be challenging in the absence of an attitude control system and in the presence of nearly zero-gravity environments with uncertain surface terrain and unknown mechanical properties. This paper presents recent advancements in developing a novel landing and anchoring control system for the exploration of small bodies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ghavimi, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 2 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 609 EP 614 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700082 ER PT S AU Johnson, AE Matthies, LH AF Johnson, AE Matthies, LH BE Perry, M TI Precise image-based motion estimation for autonomous small body exploration SO ISAIRAS '99: FIFTH INTERNATIONAL SYMPOSIUM ON ARTIFICIAL INTELLIGENCE, ROBOTICS AND AUTOMATION IN SPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th International Symposium on Artificial Intelligence, Robotics and Automation in Space (ISAIRAS 99) CY JUN 01-03, 1999 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, Italian Space Agcy, Italy, French Natl Space Agcy, France, Inst Space & Astronaut Sci, Japan, Natl Aerosp Lab, Japan, NASA, US, Natl Space Dev Agcy, Japan, Netherlands Agcy Aerosp Programs, Netherlands ID COMPUTER AB Space science and solar system exploration are driving NasA to develope an array of small body missions ranging in scope from near body flybys to complete sample return. This paper presents an algorithm for on board motion estimation that will enable the precision guidance necessary for autonomatic feature tracking between a pair of descent camera images followed by two frame motion estimation and scale recovery using laser altimetry data. The output of algorithm is an estimate of rigid motion (attitude and position) and motion covariance between frames. This motion estimate can be passed directly to the spacecraft guidance and control system to enable rapid execution of safe and precise trajectories. C1 CALTECH, Jet Prop Lab, Autonomy & Control Sect, Pasadena, CA 91109 USA. RP Johnson, AE (reprint author), CALTECH, Jet Prop Lab, Autonomy & Control Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 9 Z9 9 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-760-7 J9 ESA SP PUBL PY 1999 VL 440 BP 627 EP 634 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Computer Science GA BN59B UT WOS:000082313700085 ER PT B AU Noor, AK Peters, JM AF Noor, AK Peters, JM BE Mang, HA Rammerstorfer, FG TI Recent advances in sensitivity analysis for nonlinear structural mechanics problems SO IUTAM SYMPOSIUM ON DISCRETIZATION METHODS IN STRUCTURAL MECHANICS SE SOLID MECHANICS AND ITS APPLICATIONS LA English DT Proceedings Paper CT IUTAM/IACM Symposium on Discretization Methods in Structural Mechanics CY JUN 02-06, 1997 CL AUSTRALIAN ACAD SCI, VIENNA, AUSTRIA SP Int Union Theoret & Appl Mech, Int Assoc Computat Mech, IUTAM, IACM Working Party Computat Mech, Austrian Acad Sci, Austrian Fed Minist Sci & Transport, Creditanstalt Wien Rilkeplatz, Austria, Vienna Univ Technol, Inst Strength Mat, Austria, Vienna Univ Technol, Inst Lightweight struct & Aerosp Engn, Austria HO AUSTRALIAN ACAD SCI ID DISTRIBUTED-MEMORY COMPUTERS; REDUCED-BASIS TECHNIQUE; ELASTOPLASTICITY; SYSTEMS; PANELS AB Recent developments in the sensitivity analysis for nonlinear structural mechanics and dynamics problems are reviewed. The activities are grouped into two general categories, namely, computational strategies and facilities for evaluating the sensitivity coefficients, and new applications. Brief description is given of the activities pertaining to the first category. More detailed discussion is presented fbr two recent applications: a) hierarchical sensitivity coefficients of the various response quantities of sandwich panels with composite face sheets with respect to the different laminate, layer and micromechanical characteristics of the face sheets and core; and b) sensitivity analysis of the large strain response of viscoplastic solids subjected to dynamic loading. Sample numerical results are presented and some of the future directions for research on sensitivity analysis of large-scale nonlinear structures are outlined. 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 27 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5591-1 J9 SOLID MECH APPL PY 1999 VL 68 BP 207 EP 216 PG 10 WC Mechanics SC Mechanics GA BN24Q UT WOS:000081260200024 ER PT B AU Chandrasekhara, MS Wilder, MC Carr, LW AF Chandrasekhara, MS Wilder, MC Carr, LW BE Meier, GEA Viswanath, PR TI The control of compressible dynamic stall using adaptive airfoils SO IUTAM SYMPOSIUM ON MECHANICS OF PASSIVE AND ACTIVE FLOW CONTROL SE FLUID MECHANICS AND ITS APPLICATIONS LA English DT Proceedings Paper CT IUTAM Symposium on Mechanics of Passive and Active Flow Control CY SEP 07-11, 1998 CL GOTTINGEN, GERMANY SP Deutsch Zentrum Luft & Raumfahrt eV, Int Union Theoret & Appl Mech, Offset & Dissertat Druck Jurgen Kinzel, Sartorius AG, Sparkasse Gottingen, Volksbank Gottingen C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chandrasekhara, MS (reprint author), NASA, Ames Res Ctr, MS 260-1, Moffett Field, CA 94035 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5928-3 J9 FLUID MEC A PY 1999 VL 53 BP 75 EP 80 PG 6 WC Automation & Control Systems; Mechanics SC Automation & Control Systems; Mechanics GA BP62G UT WOS:000085708300011 ER PT B AU Lin, JC AF Lin, JC BE Meier, GEA Viswanath, PR TI Application of micro-vortex generators for turbulent flow separation control SO IUTAM SYMPOSIUM ON MECHANICS OF PASSIVE AND ACTIVE FLOW CONTROL SE FLUID MECHANICS AND ITS APPLICATIONS LA English DT Proceedings Paper CT IUTAM Symposium on Mechanics of Passive and Active Flow Control CY SEP 07-11, 1998 CL GOTTINGEN, GERMANY SP Deutsch Zentrum Luft & Raumfahrt eV, Int Union Theoret & Appl Mech, Offset & Dissertat Druck Jurgen Kinzel, Sartorius AG, Sparkasse Gottingen, Volksbank Gottingen C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lin, JC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 11 TC 3 Z9 3 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5928-3 J9 FLUID MEC A PY 1999 VL 53 BP 81 EP 88 PG 8 WC Automation & Control Systems; Mechanics SC Automation & Control Systems; Mechanics GA BP62G UT WOS:000085708300012 ER PT S AU Jones, JP Nitzberg, B AF Jones, JP Nitzberg, B BE Feielson, DG Rudolph, L TI Scheduling for parallel supercomputing: A historical perspective of achievable utilization SO JOB SCHEDULING STRATEGIES FOR PARALLEL PROCESSING SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 5th Annual Workshop on Job Scheduling Strategies for Parallel Processing held in Conjunction with the IPPS/SPDP '99 Conference CY APR 16, 1999 CL SAN JUAN, PR SP IPPS, SPDP AB The NAS facility has operated parallel supercomputers for the past 11 years, including the Intel iPSC/860, Intel Paragon, Thinking Machines CM-5, IBM SP-2, and Gray Origin 2000. Across this wide variety of machine architectures, across a span of 10 years, across a large number of different users, and through thousands of minor configuration and policy changes, the utilization of these machines shows three general trends: (1) scheduling using a naive FCFS first-fit policy results in 40-60% utilization, (2) switching to the more sophisticated dynamic backfilling scheduling algorithm improves utilization by about 15 percentage points (yielding about 70% utilization), and (3) reducing the maximum allowable job size further increases utilization. Most surprising is the consistency of these trends. Over the lifetime of the NAS parallel systems, we made hundreds, perhaps thousands, of small changes to hardware, software, and policy, yet utilization was affected little. In particular, these results show that the goal of achieving near 100% utilization while supporting a real parallel supercomputing workload is unrealistic. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MRJ Technol Solut, M-S 258-6, Moffett Field, CA 94035 USA. EM jjones@nas.nasa.gov NR 12 TC 33 Z9 33 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66676-1 J9 LECT NOTES COMPUT SC PY 1999 VL 1659 BP 1 EP 16 PG 16 WC Computer Science, Theory & Methods SC Computer Science GA BR52F UT WOS:000166710400001 ER PT S AU Chapin, SJ Cirne, W Feitelson, DG Jones, JP Leutenegger, ST Schwiegelshohn, U Smith, W Talby, D AF Chapin, SJ Cirne, W Feitelson, DG Jones, JP Leutenegger, ST Schwiegelshohn, U Smith, W Talby, D BE Feielson, DG Rudolph, L TI Benchmarks and standards for the evaluation of parallel job schedulers SO JOB SCHEDULING STRATEGIES FOR PARALLEL PROCESSING SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 5th Annual Workshop on Job Scheduling Strategies for Parallel Processing held in Conjunction with the IPPS/SPDP '99 Conference CY APR 16, 1999 CL SAN JUAN, PR SP IPPS, SPDP ID TRACE-DRIVEN SIMULATION; WORKLOAD CHARACTERIZATION; PROCESSOR ALLOCATION; SYSTEMS; METASYSTEMS; COMPUTER AB The evaluation of parallel job schedulers hinges on the workloads used. It is suggested that this be standardized, in terms of both format and content, so as to ease the evaluation and comparison of different systems. The question remains whether this can encompass both traditional parallel systems and metacomputing systems. This paper is based on a panel on this subject that was held at the workshop, and the ensuing discussion; its authors are both the panel members and participants from the audience. Naturally, not all of us agree with all the opinions expressed here... C1 Syracuse Univ, Dept Elect Engn & Comp Sci, Syracuse, NY 13244 USA. Univ Calif San Diego, Dept Comp Sci & Engn, La Jolla, CA 92093 USA. Hebrew Univ Jerusalem, Inst Comp Sci, IL-91904 Jerusalem, Israel. NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. Univ Denver, Dept Math & Comp Sci, Denver, CO 80208 USA. Univ Dortmund, Comp Engn Inst, D-44221 Dortmund, Germany. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP Chapin, SJ (reprint author), Syracuse Univ, Dept Elect Engn & Comp Sci, Syracuse, NY 13244 USA. EM chapin@cs.virginia.edu; walfredo@cs.ucsd.edu; feit@cs.huji.ac.il; jjones@nas.nasa.gov; leut@cs.du.edu; uwe@ds.e-technik.uni-dortmund.de; wsmith@mcs.anl.gov; davidt@cs.huji.ac.il NR 63 TC 34 Z9 34 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66676-1 J9 LECT NOTES COMPUT SC PY 1999 VL 1659 BP 67 EP 90 PG 24 WC Computer Science, Theory & Methods SC Computer Science GA BR52F UT WOS:000166710400004 ER PT S AU Martin, MD Hyon, JJ AF Martin, MD Hyon, JJ GP SOC PHOTOOPT INSTRUMENTAT ENGINEERS SOC PHOTOOPT INSTRUMENTAT ENGINEERS TI Evaluation of DVD-R for archival applications SO JOINT INTERNATIONAL SYMPOSIUM ON OPTICAL MEMORY AND OPTICAL DATA STORAGE 1999 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Joint International Symposium on Optical Memory and Optical Data Storage (ISOM/ODS 99) CY JUL 11-15, 1999 CL KOLOA, HI SP IEEE, Lasers & Electroopt Soc, Opt Soc Amer, SPIE, Int Soc Opt Engn, Japan Soc Appl Phys C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Martin, MD (reprint author), CALTECH, Jet Prop Lab, Mail Stop 171-264,4800 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 0-8194-3458-2 J9 P SOC PHOTO-OPT INS PY 1999 VL 3864 BP 86 EP 88 PG 3 WC Computer Science, Hardware & Architecture; Optics; Physics, Applied SC Computer Science; Optics; Physics GA BN96P UT WOS:000083679500027 ER PT S AU Chao, TH Zhou, HY Reyes, G AF Chao, TH Zhou, HY Reyes, G GP SOC PHOTOOPT INSTRUMENTAT ENGINEERS SOC PHOTOOPT INSTRUMENTAT ENGINEERS TI High-density holographic memory and its applications to optical pattern recognition SO JOINT INTERNATIONAL SYMPOSIUM ON OPTICAL MEMORY AND OPTICAL DATA STORAGE 1999 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Joint International Symposium on Optical Memory and Optical Data Storage (ISOM/ODS 99) CY JUL 11-15, 1999 CL KOLOA, HI SP IEEE, Lasers & Electroopt Soc, Opt Soc Amer, SPIE, Int Soc Opt Engn, Japan Soc Appl Phys C1 CALTECH, Jet Prop Lab, Pasadena, CA 91355 USA. RP Chao, TH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91355 USA. NR 3 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 0-8194-3458-2 J9 P SOC PHOTO-OPT INS PY 1999 VL 3864 BP 181 EP 183 PG 3 WC Computer Science, Hardware & Architecture; Optics; Physics, Applied SC Computer Science; Optics; Physics GA BN96P UT WOS:000083679500058 ER PT J AU Cobb, TQ Johnson, WS Lowther, SE St Clair, TL AF Cobb, TQ Johnson, WS Lowther, SE St Clair, TL TI Optimization of surface treatment and adhesive selection for bond durability in Ti-15-3 laminates SO JOURNAL OF ADHESION LA English DT Article DE titanium bonding; polyimide adhesive; titanium surface treatment; high temperature bonding; titanium composite; hybrid titanium composite laminate; titanium graphite reinforced laminate; adhesive durability; aerospace bonding AB The promising mechanical performance of a baseline Hybrid Titanium Composite Laminate (HTCL) inspired an investigation into maximizing the strength and environmental performance of this new aerospace material. This research focused upon finding the strongest and most durably combination of three commercially-available titanium surface treatments (i.e., Pasa-Jell 107(TM), Boeing's Sol-Gel, and Turco 5578(R)) and two polyimide adhesives (i.e., LaRC(TM)-IAX and FM5(R)) for use in HTCL. The tests employed the cracked-lap shear (CLS) specimen geometry for fatigue crack growth measurements and also for fracture toughness analyses of the bonded specimens. The CLS geometry models several bonded applications found in the aerospace industry, and it also represents the debonding characteristics of a cracked titanium foil in HTCL. The environmental performance of these six material combinations has been evaluated after 5,000 hours of continuous exposure to either a Hot/Wet environment that subjected the bonded specimens to 160 degrees F (71 degrees C) with relative humidity in excess of 95%, or to a Hot/Dry environment of 350 degrees F (177 degrees C) with a relative humidity of less than 5%. These two exposure environments utilized in this study are the most aggressive long-term environments that the HTCL is projected to experience while in service. Test results showed that the best combination of the titanium surface treatments and the polyimide adhesives in the FM5(R) adhesive used in conjunction with Boeing's Sol-Gel titanium surface treatment. Though the FM5(R)/Sol-Gel system was the strongest of all combinations, its performance dropped to less than 50% of its original strength after exposure to the Hot/Dry environment. An important finding is that this bonded system did not significantly degrade after exposure to the Hot/Wet environment. The only other material combination that showed substantial bond strength was the FM5(R)/Pasa-Jell 107 system, though its strength also dropped to less than 50% of its original strength after exposure to the Hot/Dry environment. C1 Georgia Inst Technol, Atlanta, GA 30332 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Johnson, WS (reprint author), Georgia Inst Technol, 778 Atlantic Dr, Atlanta, GA 30332 USA. NR 20 TC 6 Z9 6 U1 0 U2 3 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0021-8464 J9 J ADHESION JI J. Adhes. PY 1999 VL 71 IS 2-3 BP 115 EP 141 DI 10.1080/00218469908014844 PG 27 WC Engineering, Chemical; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA 254AU UT WOS:000083590000001 ER PT J AU Cagliostro, DE Pallix, J Ridge, J Chao, S Hsu, MT AF Cagliostro, DE Pallix, J Ridge, J Chao, S Hsu, MT TI Multifunctional alkoxysilanes as water repellents: Waterproofing alumina thermal insulation with methyldimethoxysilane SO JOURNAL OF ADVANCED MATERIALS LA English DT Article AB Methyldimethoxysilane (MDMS), a multifunctional alkoxysilane, is an effective and rapid waterproofing agent for ceramic tiles and blankets used as thermal insulation on aerospace vehicles. This insulation is composed of silica or alumina. The physical, hydrolytic, and thermal properties of a film formed on alumina from exposure to MDMS weve measured Contact angles, spectra, and relative concentrations were reported as function of hydrolytic and thermal stability. The effectiveness of waterproofing was determined by immersion and measuring water pickup for a porous insulation. It was found that the initial film deposited was partially soluble in water but left a stable residue attached to the alumina surface. This film imparted water repellency to the alumina and was gradually lost by vaporization, solubility and chemical processes when exposed to elevated temperatures and to water At 400-600 degrees C, infrared spectra showed that both the -SiH and -SiCH3 functional groups in the film oxidized in air and water repellency, was lost. Substantial oxidation was accompanied by wetting and a decrease in contact angle. Exposure of alumina based thermal insulation to MDMS resulted in effective waterproofing at lower concentrations and in shorter exposure times compared to a monofunctional alkoxysilane, dimethyethoxysilane (DMES), presently used as a waterproofing agent. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. San Jose State Univ, San Jose, CA 95192 USA. HC Chem Co, San Jose, CA USA. RP Cagliostro, DE (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 16 TC 2 Z9 2 U1 1 U2 2 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 USA SN 1070-9789 J9 J ADV MATER JI J. Adv. Mater. PD JAN PY 1999 VL 31 IS 1 BP 27 EP 35 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 209HY UT WOS:000081043200005 ER PT J AU Noor, AK Peters, JM AF Noor, AK Peters, JM TI Analysis of composite panels subjected to thermo-mechanical loads SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article ID REDUCED BASIS TECHNIQUE; FLAT AB The results of a detailed study of the effect of cutout on the nonlinear response of curved unstiffened panels are presented. The panels are subjected to combined temperature gradient through-the-thickness combined with pressure loading and edge shortening or edge shear. The analysis is based on a first-order, shear-deformation, Sanders-Budiansky-type shell theory with the effects of large displacements, moderate rotations, transverse shear deformation, and laminated anisotropic material behavior included. A mixed formulation is used with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the panel. The nonlinear displacements, strain energy, principal strains, transverse shear stresses, transverse shear strain energy density, and their hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the nonlinear response to variations in the panel parameters, as well as in the material properties of the individual layers. Numerical results are presented for cylindrical panels and show the effects of variations in the loading and the size of the cutout on the global and local response quantities as well as their sensitivity to changes in the various panel, layer, and micromechanical parameters. 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 12 TC 7 Z9 7 U1 0 U2 0 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD JAN PY 1999 VL 12 IS 1 BP 1 EP 5 DI 10.1061/(ASCE)0893-1321(1999)12:1(1) PG 5 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 147AD UT WOS:000077465300001 ER PT J AU Giles, GL AF Giles, GL TI Design-oriented analysis of aircraft fuselage structures using equivalent plate methodology SO JOURNAL OF AIRCRAFT LA English DT Article ID ANALYTIC SENSITIVITIES; SHAPE OPTIMIZATION AB A design-oriented analysis capability for aircraft fuselage structures that utilizes equivalent plate methodology is described. This new capability is implemented as an addition to the existing wing-analysis procedure in the equivalent Laminated plate solution (ELAPS) computer code. The wing and fuselage analyses are combined to model entire airframes. The paper focuses on the fuselage model definition, the associated analytical formulation, and the approach used to couple the wing and fuselage analyses. The modeling approach used to minimize the amount of preparation of input data by the user and to facilitate the making of design changes is described. The fuselage analysis is based on ring and shell equations, but the procedure is formulated to be analogous to that used for plates to take advantage of the existing code in ELAPS. Connector springs are used to couple the wing and fuselage models. Typical fuselage analysis results are presented for two analytical models. Results for a ring-stiffened cylinder model are compared with results from conventional finite element analyses to assess the accuracy of this new analysis capability. The connection of plate and ring segments is demonstrated using a second model that is representative of the wing structure for a channel-wing aircraft configuration. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Giles, GL (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 24 TC 6 Z9 7 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 1999 VL 36 IS 1 BP 21 EP 28 DI 10.2514/2.2441 PG 8 WC Engineering, Aerospace SC Engineering GA 165YW UT WOS:000078550300004 ER PT J AU Reuther, JJ Jameson, A Alonso, JJ Rimlinger, MJ Saunders, D AF Reuther, JJ Jameson, A Alonso, JJ Rimlinger, MJ Saunders, D TI Constrained multipoint aerodynamic shape optimization using an adjoint formulation and parallel computers, part 1 SO JOURNAL OF AIRCRAFT LA English DT Article AB This paper is the first of a two-paper series (Reuther, J. J,, Jameson, A., Alonso, J, J., Rimlinger, M, J,, and Saunders, D,, ("Constrained Multipoint Aerodynamic Shape Optimization Using an Adjoint Formulation and Parallel Computers, Part 2," Journal of Aircraft, Vol, 36, No, 1, 1999, pp, 61-74), that describes a shape optimization method for aerodynamic design problems invoking complex aircraft configurations and multiple design points that are subject to geometric constraints. The aerodynamic performance is evaluated using a set of high-fidelity governing equations discretized on body-conforming multiblock meshes. The design process is greatly accelerated through the use of an adjoint method for the calculation of sensitivity information and by means of a parallel implementation for distributed memory computers. This paper focuses on the details of the development and implementation of the complete design algorithm. A general adjoint formulation of the design optimization problem is presented along with a detailed derivation of the adjoint system for the Euler equations. The multiblock approach for the now and adjoint solution algorithm and the mesh perturbation procedure are described. The extension of this approach to treat multipoint and constrained shape optimization of complete aircraft configurations is also discussed. Finally, the details of the parallel implementation are examined. C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. Stanford Univ, Dept Aeronaut & Astronaut, Stanford, CA 94305 USA. RP Reuther, JJ (reprint author), NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. NR 56 TC 115 Z9 118 U1 0 U2 10 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 1999 VL 36 IS 1 BP 51 EP 60 DI 10.2514/2.2413 PG 10 WC Engineering, Aerospace SC Engineering GA 165YW UT WOS:000078550300007 ER PT J AU Reuther, JJ Jameson, A Alonso, JJ Rimlinger, MJ Saunders, D AF Reuther, JJ Jameson, A Alonso, JJ Rimlinger, MJ Saunders, D TI Constrained multipoint aerodynamic shape optimization using an adjoint formulation and parallel computers, part 2 SO JOURNAL OF AIRCRAFT LA English DT Article AB This is the second part of a two-paper series that describes the derivation, development, add practical application of a shape optimization method for aerodynamic design problems involving complex aircraft configurations including multiple design points, subject to geometric constraints. The aerodynamic performance is evaluated using the Euler equations discretized on body-conforming multiblock meshes, The design process is greatly accelerated by the use of control theory for the calculation of sensitivity information and the implementation of the method on distributed memory parallel computers. Whereas the first paper of the series (Reuther, J. J,, Jameson, A., Alonso, J, J., Rimlinger, M. J., and Saunders, D., "Constrained Multipoint Aerodynamic Shape Optimization Using an Adjoint Formulation and Parallel Computers, Part 1," Jounrnal of Aircraft, Vol. 36, No. 1 1999, pp, 51-60) placed emphasis on the foundations of the control theory approach and presented a general framework for the design of complex configurations, this second paper focuses on the performance of the overall design method and its practical application to realistic design problems. More specifically, the accuracy of the adjoint-based sensitivity information is examined and compared with the sensitivities provided by the finite difference method. The parallel scalability of the design method is analyzed and demonstrated. Aerodynamic performance improvements are obtained for example wing design problems using both multipoint drag minimization and single-point inverse techniques. Design examples include both transonic and supersonic cases and involve wing aerodynamic design in the presense of complex aircraft configurations with all resulting configurations satisfying geometric constraints. C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. Stanford Univ, Dept Aeronaut & Astronaut, Stanford, CA 94305 USA. RP Reuther, JJ (reprint author), NASA, Ames Res Ctr, Adv Comp Sci Res Inst, M-S 227-6, Moffett Field, CA 94035 USA. NR 11 TC 59 Z9 60 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 1999 VL 36 IS 1 BP 61 EP 74 DI 10.2514/2.2414 PG 14 WC Engineering, Aerospace SC Engineering GA 165YW UT WOS:000078550300008 ER PT J AU Newman, JC Taylor, AC Barnwell, RW Newman, PA Hou, GJW AF Newman, JC Taylor, AC Barnwell, RW Newman, PA Hou, GJW TI Overview of sensitivity analysis and shape optimization for complex aerodynamic configurations SO JOURNAL OF AIRCRAFT LA English DT Review ID AUTOMATIC DIFFERENTIATION; DESIGN; DERIVATIVES; EQUATIONS; FLOW; STRATEGY; SYSTEMS AB This paper presents a brief overview of some of the more recent advances in steady aerodynamic shape-design sensitivity analysis and optimization, based on advanced computational fluid dynamics (CFD), The focus here is on those methods particularly well-suited to the study of geometrically complex configurations and their potentially complex associated flow physics. When nonlinear state equations are considered in the optimization process, difficulties are found in the application of sensitivity analysis. Some techniques for circumventing such difficulties are currently being explored and are included here. Attention is directed to methods that utilize automatic differentiation to obtain aerodynamic sensitivity derivatives for both complex configurations and complex flow physics. Various examples of shape-design sensitivity analysis for unstructured-grid CFD algorithms are demonstrated for different formulations of the sensitivity equations. Finally, the use of advanced, unstructured-grid CFDs in multidisciplinary analyses and multidisciplinary sensitivity analyses within future optimization processes is recommended and encouraged. C1 Mississippi State Univ, Dept Aerosp Engn, Mississippi State, MS 39762 USA. Old Dominion Univ, Dept Engn Mech, Norfolk, VA 23529 USA. Virginia Polytech Inst & State Univ, Virginia Consortium Engn & Sci Univ, Dept Aerosp & Ocean Engn, Hampton, VA 23666 USA. Virginia Polytech Inst & State Univ, Dept Engn Sci & Mech, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Hampton, VA 23681 USA. RP Newman, JC (reprint author), Mississippi State Univ, Dept Aerosp Engn, Mississippi State, MS 39762 USA. NR 121 TC 66 Z9 69 U1 2 U2 17 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 1999 VL 36 IS 1 BP 87 EP 96 DI 10.2514/2.2416 PG 10 WC Engineering, Aerospace SC Engineering GA 165YW UT WOS:000078550300010 ER PT J AU Samareh, JA AF Samareh, JA TI Status and future of geometry modeling and grid generation for design and optimization SO JOURNAL OF AIRCRAFT LA English DT Article ID HEXAHEDRAL MESH GENERATION; B-SPLINES; COMPUTATIONS; FLUID AB Geometry modeling and grid generation (GMGG) have played, and will continue to play, an important role in computational aerosciences. During the last two decades, tremendous progress has occurred in GMGG; however, GMGG is still the biggest bottleneck to routine applications for complicated computational fluid dynamics and computational structures mechanics models for analysis, design, and optimization. We are still far from incorporating GMGG tools in a design and optimization environment for complicated configurations. It is still a challenging task to parameterize an existing model in today's computer-aided design systems, and the models created are not always good enough for automatic grid generation tools. Despite many advances in grid generation, the process is still the most labor-intensive and time-consuming part of the computational aerosciences for analysis, design, and optimization. In an ideal design environment, a design engineer would use a parametric model to evaluate alternative designs effortlessly and optimize an existing design for a new set of design objectives and constraints. For this ideal environment to be realized, the GMGG tools must have the following characteristics: 1) be automated, 2) provide consistent geometry across all disciplines, 3) be parametric, 4) provide sensitivity derivatives, and 5) fit in the product development cycle times. This paper reviews the status of GMGG for analysis, design, and optimization processes, and it focuses on some emerging ideas that will advance the GMGG toward the ideal design environment. C1 NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Hampton, VA 23681 USA. RP Samareh, JA (reprint author), NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, MS 159, Hampton, VA 23681 USA. EM j.a.samareh@larc.nasa.gov NR 81 TC 29 Z9 29 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 1999 VL 36 IS 1 BP 97 EP 104 DI 10.2514/2.2417 PG 8 WC Engineering, Aerospace SC Engineering GA 165YW UT WOS:000078550300011 ER PT J AU Chamis, CC AF Chamis, CC TI Coupled multidisciplinary optimization of engine structural performance SO JOURNAL OF AIRCRAFT LA English DT Article AB Effective computational simulation procedures are described for modeling the inherent multidisciplinary interactions that govern the accurate response of propulsion structural systems, Results are presented for propulsion system structural responses including multidisciplinary coupling effects using 1) coupled multidiscipline thermal/structural/acoustic tailoring, 2) an integrated system of multidisciplinary simulators, 3) coupled material-behavior/fabrication process tailoring, 4) sensitivities using a probabilistic simulator, 5) a coupled materials/structures/fracture/probabilistic behavior simulator, and 6) engine structure technology benefit estimators. The results demonstrate that superior designs can be achieved if the analysis/tailoring methods account for the multidisciplinary coupling effects. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chamis, CC (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 21 TC 4 Z9 4 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 1999 VL 36 IS 1 BP 190 EP 199 DI 10.2514/2.2425 PG 10 WC Engineering, Aerospace SC Engineering GA 165YW UT WOS:000078550300018 ER PT J AU Rowell, LF Braun, RD Olds, JR Unal, R AF Rowell, LF Braun, RD Olds, JR Unal, R TI Multidisciplinary conceptual design optimization of space transportation systems SO JOURNAL OF AIRCRAFT LA English DT Article ID LAUNCH-VEHICLE DESIGN; ALGORITHM AB This paper presents a recent history of progress both in disciplinary modeling and in optimization methods and frameworks for space transportation systems conceptual design and analysis. The disciplinary models and process typically used for space transportation analyses are identified, including physics-based and empirical models. The diverse characteristics of these disciplinary models require equally diverse integration and optimization approaches to enable implementation of automated, multidisciplinary design systems. Two general approaches are described for integrating these disciplinary models into computational frameworks for automated vehicle synthesis and optimization. Several optimization approaches are discussed including parameter, gradient-based, stochastic, and collaborative methods. Representative examples are given of multidisciplinary applications of optimization methods to the launch vehicle conceptual design problem. A primary goal for the future is to enable a space transportation design-to-cost capability. C1 NASA, Langley Res Ctr, Vehicle Anal Branch, Hampton, VA 23681 USA. Georgia Inst Technol, Sch Aerosp Engn, Atlanta, GA 30332 USA. Old Dominion Univ, Dept Engn Management, Norfolk, VA 23529 USA. RP Rowell, LF (reprint author), NASA, Langley Res Ctr, Vehicle Anal Branch, Hampton, VA 23681 USA. NR 48 TC 13 Z9 13 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 1999 VL 36 IS 1 BP 218 EP 226 DI 10.2514/2.2428 PG 9 WC Engineering, Aerospace SC Engineering GA 165YW UT WOS:000078550300021 ER PT J AU Rogers, JL AF Rogers, JL TI Tools and techniques for decomposing and managing complex design projects SO JOURNAL OF AIRCRAFT LA English DT Article AB Many companies are looking for new tools and techniques to aid a design manager in making decisions that can reduce the time and cost of a design cycle. One tool that is available to aid in this decision-making process is the design manager's aid for intelligent decomposition (DeMAID). Since the initial public release of DeMAID in 1989, much research has been done in the areas of decomposition, concurrent engineering, and process management, and many new tools and techniques have been developed. Based on this research and development, numerous enhancements have been added to DeMAID to aid the design manager in saving both cost and time in a design cycle. The key enhancement, a genetic algorithm (GA), is available in the most recent public release called DeMAID/GA. The GA orders the sequence of design processes to minimize the cost and time to converge to a solution. Several of the most recent advances are discussed and compared with the enhancements in DeMAID/GA. An example of an aircraft conceptual design project is used to show how these enhancements can be applied to improve the design cycle. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Rogers, JL (reprint author), NASA, Langley Res Ctr, M-S 159, Hampton, VA 23681 USA. NR 27 TC 13 Z9 13 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 1999 VL 36 IS 1 BP 266 EP 274 DI 10.2514/2.2434 PG 9 WC Engineering, Aerospace SC Engineering GA 165YW UT WOS:000078550300026 ER PT J AU Schols, JL Weinman, JA Alexander, GD Stewart, RE Angus, LJ Lee, ACL AF Schols, JL Weinman, JA Alexander, GD Stewart, RE Angus, LJ Lee, ACL TI Microwave properties of frozen precipitation around a North Atlantic cyclone SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID BULK ICE SCHEME; RADIATIVE-TRANSFER; MODEL; RADAR; STORMS; SNOWFLAKES; LAYER; SNOW AB Microwave brightness temperatures emanating from a North Atlantic cyclone were measured by the Special Sensor Microwave/Imager (SSM/I) on the Defense Meteorological Satellite Program satellite. As other investigators have found before, low 85.5-GHz brightness temperatures (215 +/- 20 K) were observed from cumulonimbus clouds along the squall line; however, 85.5-GHz microwave brightness temperatures observed from the nimbostratus clouds north of the low center were significantly higher (255 +/- 20 K). In situ measurements from aircraft during the Canadian Atlantic Storm Program II showed that heavy snowfall consisting of large tenuous aggregates existed in the nimbostratus clouds at the time of the SSM/I overpass. Distributions of snow, rain, liquid cloud water, and cloud ice mass were computed from a modified version of the fifth-generation Pennsylvania State University-NCAR Mesoscale Model. That model employed a mixed-phase ice microphysics (MPIM) scheme that only considered one type of frozen hydrometeor. The frozen hydrometeor size distributions, density, and mass flux were modified to match the in situ observations where they were available and to account for the SSM/I observations using radiative transfer theory. Those revised hydrometeor representations were constrained to preserve the vertical hydrometeor mass flux distributions obtained from the MPIM scheme throughout the analysis. Frozen dense accreted particles were required near the squall line to account for the microwave scattering effect. Snow aggregates, with density that decreased with increasing size, were needed to reproduce the high brightness temperatures observed from the nimbostratus clouds. C1 SAIC, GSC, Seabrook, MD 20706 USA. NASA, Goddard Space Flight Ctr, Microwave Sensors Branch, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD USA. Atmospher Environm Serv, Downsview, ON, Canada. NOAA, FSL, Boulder, CO USA. UK Meteorol Off, Farnborough, Hants, England. RP Schols, JL (reprint author), SAIC, GSC, 7501 Forbes Blvd,S 103, Seabrook, MD 20706 USA. EM schols@ltpmail.gsfc.nasa.gov NR 41 TC 23 Z9 24 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JAN PY 1999 VL 38 IS 1 BP 29 EP 43 DI 10.1175/1520-0450(1999)038<0029:MPOFPA>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 157HC UT WOS:000078054700003 ER PT J AU Chien, S Stechert, A Mutz, D AF Chien, S Stechert, A Mutz, D TI Efficient heuristic hypothesis ranking SO JOURNAL OF ARTIFICIAL INTELLIGENCE RESEARCH LA English DT Article AB This paper considers the problem of learning the ranking of a set of stochastic alternatives based upon incomplete information (i.e., a limited number of samples). We describe a system that, at each decision cycle, outputs either a complete ordering on the hypotheses or decides to gather additional information (i.e., observations) at some cost. The ranking problem is a generalization of the previously studied hypothesis selection problem-in selection, an algorithm must select the single best hypothesis, while in ranking, an algorithm must order all the hypotheses. The central problem we address is achieving the desired ranking quality while minimizing the cost of acquiring additional samples. We describe two algorithms for hypothesis ranking and their application for the 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 and real-world datasets. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chien, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 20 TC 3 Z9 4 U1 0 U2 1 PU AI ACCESS FOUNDATION PI MARINA DEL REY PA USC INFORMATION SCIENCES INST, 4676 ADMIRALITY WAY, MARINA DEL REY, CA 90292-6695 USA SN 1076-9757 J9 J ARTIF INTELL RES JI J. Artif. Intell. Res. PY 1999 VL 10 BP 375 EP 397 PG 23 WC Computer Science, Artificial Intelligence SC Computer Science GA 208YG UT WOS:000081019600001 ER PT J AU Haeffelin, M Kandel, R Stubenrauch, C AF Haeffelin, M Kandel, R Stubenrauch, C TI Improved diurnal interpolation of reflected broadband shortwave observations using ISCCP data SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID RADIATION BUDGET EXPERIMENT; OUTGOING LONGWAVE RADIATION; METEOSAT OBSERVATIONS; EXPERIMENT ERBE; EARTH; CLOUD; VARIABILITY; CLIMATE AB The multisatellite Earth Radiation Budget Experiment (ERBE) was designed to provide complete temporal coverage of the solar-reflected and earth-emitted radiation. Following operation of ERBE scanners on as Few as one and as many as three satellites between November 1984 and February 1990, narrow-held-of-view earth radiation budget measurements were resumed in March 1994 by the Scanner for Radiation Budget (ScaRaB) mission and in December 1997 by the first Clouds and the Earth's Radiant Energy System (CERES) instrument, each time on a single satellite. Due to sparse temporal sampling, diurnal variations must be accounted for in order to establish accurate unbiased daily and monthly mean radiant exitance. When the ERBE diurnal interpolation algorithm is used alone, large discrepancies appear between monthly mean radiative fluxes obtained from single- and multisatellite data. The authors extend the algorithm by accounting for diurnally varying cloud cover using International Satellite Cloud Climatology Project (ISCCP) data products. Significant improvements are found in regions where clouds have a pronounced diurnal cycle. Further improvements are obtained by also taking into account diurnal variations of cloud properties such as optical thickness using either ISCCP cloud radiance data or a cloud classification. These approaches require the development of directional models to represent the angular dependence of the cloud albedo corresponding to the ISCCP cloud classification. C1 Ecole Polytech, Meteorol Dynam Lab, Palaiseau, France. RP Haeffelin, M (reprint author), NASA, Langley Res Ctr, Ms 420, Hampton, VA 23681 USA. NR 23 TC 10 Z9 10 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JAN PY 1999 VL 16 IS 1 BP 38 EP 54 DI 10.1175/1520-0426(1999)016<0038:IDIORB>2.0.CO;2 PG 17 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 160YU UT WOS:000078261600004 ER PT J AU Considine, GD AF Considine, GD TI Examining horizontal variability in ground-based microwave retrievals of liquid water path SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID BOUNDARY-LAYER CLOUDS; FLUXES; MODEL AB Estimating horizontal length scales associated with variability in cloud liquid water path (LWP) is important in improving both satellite retrievals of cloud properties and in improving cloud models. A microwave radiometer (MWR) at the Atmospheric Radiation Measurement Southern Great Plains (SGP) site provides measurements of the horizontal variability in cloud LWP. Estimating the length scales in time series is typically done using Fourier analysis, but Fourier methods can be quite badly biased by the presence of intermittency in the data, Cloud LWP can contain very localized structures due to convective plumes, so there is some question as to whether decomposing the measurements into a series of Fourier modes will provide physically meaningful results. To explore this problem, LWP measurements are simultaneously decomposed into a series of Fourier modes along with a series of discrete pulses. The pulses in the fitted basis set tend to pick up intermittency, so that the resulting magnitudes of Fourier modes have been filtered of discrete structures. This method, once demonstrated to be effective on proxy data, is applied to analyze the MWR LWP measurements. The results indicate that applying Fourier analysis to gauge scales of variability in LWP over the SGP site can yield misleading results. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Considine, GD (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Mail Stop 401-B, Hampton, VA 23681 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JAN PY 1999 VL 16 IS 1 BP 70 EP 79 DI 10.1175/1520-0426(1999)016<0070:EHVIGB>2.0.CO;2 PG 10 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 160YU UT WOS:000078261600006 ER PT J AU McKeown, W Leighton, R AF McKeown, W Leighton, R TI Mapping heat flux SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID THERMAL-BOUNDARY-LAYER; AIR-WATER-INTERFACE; OPTICAL-CONSTANTS AB An infrared camera technique designed for remote sensing of air-water heat flux has been developed. The technique uses the differential absorption of water between 3.817 and 4.514 microns. This difference causes each channel's radiance to originate over a different range of depths inside the air-water interface temperature gradient. Since this gradient varies only with total heat flux, the radiance difference between channels caused by the gradient also varies with heat flux. Laboratory experiments showed that this radiance difference correlates well with heat flux measured independently with calorimetry. A regression relation between camera output and heat flux is determined initially using time variations of the radiance difference and heat Aux, This relation is modified by a partial differential analysis of the relative contributions of temperature and heat Aux using data from experiments designed for this evaluation. The result is applied to the spatial variations of radiance difference in a single image pair. Error is controlled in this sensitive measurement with narrowband filters, a low-noise infrared camera, and frame averaging. averaging ail image pixels reduces modeled and measured error to rmse Q congruent to 3.1 W m(-2). C1 USN, Res Lab, Div Oceanog, Remote Sensing Applicat,Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. USN, Res Lab, Washington, DC 20375 USA. RP McKeown, W (reprint author), USN, Res Lab, Div Oceanog, Remote Sensing Applicat,Stennis Space Ctr, Code 7340, Stennis Space Ctr, MS 39529 USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JAN PY 1999 VL 16 IS 1 BP 80 EP 91 DI 10.1175/1520-0426(1999)016<0080:MHF>2.0.CO;2 PG 12 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 160YU UT WOS:000078261600007 ER PT J AU Lean, J Rind, D AF Lean, J Rind, D TI Evaluating sun-climate relationships since the Little Ice Age SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT 9th Quadrennual SCOSTEP Symposium on Solar-Terrestrial Physics CY AUG, 1997 CL UPPSALA, SWEDEN ID TOTAL SOLAR IRRADIANCE; GLOBAL CLIMATE; MAUNDER MINIMUM; TIME-SERIES; VARIABILITY; CYCLE; SOLAR-CYCLE-22; CIRCULATION; TEMPERATURE; HOLOCENE AB From the coldest period of the Little Ice Age to the present time, the surface temperature of the Earth increased by perhaps 0.8 degrees C. Solar variability may account for part of this warming which, during the past 350 years, generally tracks fluctuating solar activity levels. While increases in greenhouse gas concentrations art: widely assumed to be the primary cause of recent climate change, surface temperatures nevertheless varied significantly during pre-industrial periods, under minimal levels of greenhouse gas variations. A climate forcing of 0.3 W m(-2) arising from a speculated 0.13% solar irradiance increase can account for the 0.3 degrees C surface warming evident in the paleoclimate record from 1650 to 1790, assuming that climate sensitivity is 1 degrees C W-1 m(-2) (which is within the IPCC range). The empirical Sun-climate relationship defined by these pre-industrial data suggests that solar variability may have contributed 0.25 degrees C of the 0.6 degrees C subsequent warming from 1900 to 1990, a scenario which time dependent GCM simulations replicate when forced with reconstructed solar irradiance. Thus, while solar Variability likely played a dominant role in modulating climate during the Little Ice Age prior to 1850, its influence since 1900 has become an increasingly less significant component of climate change in the industrial epoch. It is unlikely that Sun-climate relationships can account for much of the warming since 1970, not withstanding recent attempts to deduce long term solar irradiance fluctuations from the observational data base, which has notable occurrences of instrumental drifts. Empirical evidence suggests that Sun-climate relationships exist on decadal as well as centennial time scales, but present sensitivities of the climate system are insufficient to explain these short-term relationships. Still to be simulated over the time scale of the Little Ice Age to the present is the combined effect of direct radiative forcing, indirect forcing via solar-induced ozone changes in the atmosphere, and speculated charged particle mechanisms whose pathways and sensitivities are not yet specified. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 USN, EO Hulburt Ctr Space Res, Res Lab, Washington, DC 20375 USA. Columbia Univ, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Lean, J (reprint author), USN, EO Hulburt Ctr Space Res, Res Lab, 4555 Overlook Ave SW, Washington, DC 20375 USA. OI Lean, Judith/0000-0002-0087-9639 NR 63 TC 67 Z9 75 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD JAN PY 1999 VL 61 IS 1-2 BP 25 EP 36 DI 10.1016/S1364-6826(98)00113-8 PG 12 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 180HQ UT WOS:000079380400004 ER PT J AU Bilitza, D AF Bilitza, D TI Science tools on the Internet - access to information, data and models SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT 9th Quadrennual SCOSTEP Symposium on Solar-Terrestrial Physics CY AUG, 1997 CL UPPSALA, SWEDEN AB In just a few years the Internet has become an essential element in national and international science endeavors. Transfer of data, models, and related software across the net has skyrocketed. Interactive WorldWideWeb modules let the users do everything from simply specifying time periods for data retrieval to plotting complex data sets, to computing model parameters and to finding magnetic conjunctions between points in space. This paper reviews Internet sources for solar-terrestrial data and models, with special emphasis on systems that are related to, or a result of, the Solar Terrestrial Energy Program (STEP). We also discuss on-line systems that provide specific interactive services to the research community, like data finding,, viewing, and browsing capabilities, comparison with model parameters, etc. This html document provides links to a large number of WWW sites that might be of interest for STEP research. It does not attempt to be a comprehensive guide to such sites but rather to provide access to selected typical sites for the specific capabilities discussed. Throughout the paper Universal Resource Locator (URL) addresses are highlighted in italics; the links to all the services mentioned are available on the WWW at http://nssdc.gsfc.nasa.gov/space/STEP-links.htm/. (C) 1999 Elsevier Science Ltd. All rights reserved. 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, Greenbelt, MD 20771 USA. NR 1 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD JAN PY 1999 VL 61 IS 1-2 BP 167 EP 180 DI 10.1016/S1364-6826(98)00123-0 PG 14 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 180HQ UT WOS:000079380400017 ER PT J AU Pierson, JM McKinney, KA Toohey, DW Margitan, J Schmidt, U Engel, A Newman, PA AF Pierson, JM McKinney, KA Toohey, DW Margitan, J Schmidt, U Engel, A Newman, PA TI An investigation of C1O photochemistry in the chemically perturbed arctic vortex SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE chlorine monoxide; photochemistry; modeling; partitioning ID ANTARCTIC OZONE DEPLETION; IN-SITU MEASUREMENTS; INSITU OBSERVATIONS; LOWER STRATOSPHERE; HETEROGENEOUS CHEMISTRY; CHLORINE MONOXIDE; HYDROGEN-CHLORIDE; CLO; WINTER; INSTRUMENT AB A new lightweight in, situ instrument designed to measure ClO was flown on a balloon launched into the arctic vortex at dawn on February 3, 1995 at Kiruna, Sweden during the Second European Stratospheric Arctic and Mid-latitude Experiment (SESAME), together with instruments to measure ozone and long-lived tracers. Observations on ascent and descent at different solar zenith angles are compared to results from Lagrangian and box model calculations that assume the airmasses at similar potential temperatures had comparable photochemical histories. Between 20 and 22 km, in a region where ClO was significantly enhanced, a model constrained by currently recommended rate parameters significantly underestimates the abundances of ClO that were observed on ascent at High solar zenith angles, whereas the agreement is much better if a smaller ClO-Cl2O2 equilibrium constant, one inferred from previous ER-2 aircraft observations of ClO in the Arctic during nighttime, is assumed. On ascent, ClO is additionally enhanced in a narrow region between 20 and 21 km. We believe the most plausible explanation for this feature is rapid photolysis of OClO produced by the slow bimolecular reaction ClO + ClO over the 48 hours prior to the observations when the airmass was warmed to 225 K by adiabatic compression while in polar darkness. These results suggest that under special circumstances, OClO can be produced by a reaction other than one involving BrO, and, hence, OClO is not necessarily a universal proxy for BrO abundances in the perturbed polar vortex. C1 Univ Calif Irvine, Earth Syst Sci, Irvine, CA 92697 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Frankfurt, Inst Meteorol & Geophys, D-60325 Frankfurt, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pierson, JM (reprint author), Univ Calif Irvine, Earth Syst Sci, Irvine, CA 92697 USA. RI Toohey, Darin/A-4267-2008; Newman, Paul/D-6208-2012; Engel, Andreas/E-3100-2014 OI Toohey, Darin/0000-0003-2853-1068; Newman, Paul/0000-0003-1139-2508; Engel, Andreas/0000-0003-0557-3935 NR 40 TC 28 Z9 28 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD JAN PY 1999 VL 32 IS 1 BP 61 EP 81 DI 10.1023/A:1006136712267 PG 21 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 178VE UT WOS:000079289200004 ER PT J AU Kostenuik, PJ Harris, J Halloran, BP Turner, RT Morey-Holton, ER Bikle, DD AF Kostenuik, PJ Harris, J Halloran, BP Turner, RT Morey-Holton, ER Bikle, DD TI Skeletal unloading causes resistance of osteoprogenitor cells to parathyroid hormone and to insulin-like growth factor-I SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Article ID OSTEOBLAST-ENRICHED CULTURES; FETAL-RAT BONE; OVARIECTOMIZED RATS; GENE-EXPRESSION; FEMORAL-NECK; ESTROGEN; INCREASES; DIFFERENTIATION; BISPHOSPHONATES; PROLIFERATION AB Skeletal unloading decreases bone formation and osteoblast number in vivo and decreases the number and proliferation of bone marrow osteoprogenitor (BMOp) cells in vitro, We tested the ability of parathyroid hormone (PTH) to stimulate BMOp cells in vivo by treating Sprague Dawley rats (n = 32) with intermittent PTH(1-34) (1 h/day at 8 mu g/100 g of body weight), or with vehicle via osmotic minipumps during 7 days of normal weight bearing or hind limb unloading, Marrow cells were pushed from the femur and cultured at the same initial density for up to 21 days, PTH treatment of normally loaded rats caused a 2.5-fold increase in the number of BMOp cells, with similar increases in alkaline phosphatase (ALP) activity and mineralization, compared,vith cultures from vehicle-treated rats, PTH treatment of hind limb unloaded rats failed to stimulate BMOp cell number, ALP activity, or mineralization. Hind limb unloading had no significant effect on PTH receptor mRNA or protein levels in the tibia. Direct in vitro PTH challenge of BMOp cells isolated from normally loaded bone failed to stimulate their proliferation and inhibited their differentiation, suggesting that the in vivo anabolic effect of intermittent PTH on BMOp cells was mediated indirectly by a PTH-induced factor, We hypothesize that this factor is insulin-like growth factor-I (IGF-I), which stimulated the in vitro proliferation and differentiation of BMOp cells isolated from normally loaded bone, but not from unloaded bone, These results suggest that IGF-I mediates the ability of PTH to stimulate BMOp cell proliferation in normally loaded bone, and that BMOp cells in unloaded bone are resistant to the anabolic effect of intermittent PTH therapy due to their resistance to IGF-I. C1 Vet Adm Med Ctr, San Francisco, CA 94121 USA. Univ Calif San Francisco, Dept Med, San Francisco, CA USA. Univ Calif San Francisco, Dept Physiol, San Francisco, CA USA. Boston Univ, Med Ctr, Dept Orthoped Surg, Boston, MA USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Mayo Clin, Dept Orthoped, Rochester, MN USA. Mayo Clin, Dept Biochem & Mol Biol, Rochester, MN USA. RP Bikle, DD (reprint author), Vet Adm Med Ctr, 4150 Clement St 111N, San Francisco, CA 94121 USA. NR 40 TC 88 Z9 93 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD JAN PY 1999 VL 14 IS 1 BP 21 EP 31 DI 10.1359/jbmr.1999.14.1.21 PG 11 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 151HZ UT WOS:000077715800005 PM 9893062 ER PT J AU Topaler, MS Allison, TC Schwenke, DW Truhlar, DG AF Topaler, MS Allison, TC Schwenke, DW Truhlar, DG TI What is the best semiclassical method for photochemical dynamics of systems with conical intersections? (vol 109, pg 3321, 1998) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Correction C1 Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Topaler, MS (reprint author), Univ Minnesota, Dept Chem, 207 Pleasant St SE, Minneapolis, MN 55455 USA. RI schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 1 TC 11 Z9 12 U1 0 U2 0 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 1 PY 1999 VL 110 IS 1 BP 687 EP 688 DI 10.1063/1.477916 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 151AC UT WOS:000077697900083 ER PT J AU Chou, MD Lee, KT Tsay, SC Fu, Q AF Chou, MD Lee, KT Tsay, SC Fu, Q TI Parameterization for cloud longwave scattering for use in atmospheric models SO JOURNAL OF CLIMATE LA English DT Article AB A parameterization for the scattering of thermal infrared (longwave) radiation by clouds has been developed based on discrete-ordinate multiple-scattering calculations. The effect of backscattering is folded into the emission of an atmospheric layer and the absorption between levels by scaling the cloud optical thickness. The scaling is a function of the single-scattering albedo and asymmetry factor. For wide ranges of cloud particle size, optical thickness, height, and atmospheric conditions, flux errors induced by the parameterization are small. They are <4 W m(-2) (2%) in the upward flux at the top of the atmosphere and <2 W m(-2) (1%) in the downward flux at the surface. Compared to the case that scattering by clouds is neglected, the flux errors are more than a factor of 2 smaller. The maximum error in cooling rate is approximate to 8%, which occurs at the top of clouds, as well as at the base of high clouds where the difference between the cloud and surface temperatures is large. With the scaling approximation, radiative transfer equations for a cloudy atmosphere are identical with those for a clear atmosphere, and the difficulties in applying a multiple-scattering algorithm to a partly cloudy atmosphere (assuming homogeneous clouds) are avoided. The computational efficiency is practically the same as that for a clear atmosphere. The parameterization represents a significant reduction in one source of the errors involved in the calculation of longwave cooling in cloudy atmospheres. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Kangnung Natl Univ, Dept Atmospher & Environm Sci, Kangnung, South Korea. Dalhousie Univ, Dept Oceanog, Atmospher Sci Program, Halifax, NS, Canada. RP Chou, MD (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 913, Greenbelt, MD 20771 USA. EM chou@climate.gsfc.nasa.gov RI Tsay, Si-Chee/J-1147-2014 NR 15 TC 78 Z9 80 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JAN PY 1999 VL 12 IS 1 BP 159 EP 169 DI 10.1175/1520-0442-12.1.159 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 165XZ UT WOS:000078548300014 ER PT J AU Dickinson, LC Farley, GL Hinders, MK AF Dickinson, LC Farley, GL Hinders, MK TI Prediction of effective three-dimensional elastic constants of translaminar reinforced composites SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article AB A Trans-Laminar;Reinforced (TLR) composite is defined as composite laminate with up to five percent volume of fibrous reinforcement oriented in a trans-laminar fashion in the through-thickness direction. The objective of this work was to examine the effect of important parameters on elastic response. Detailed finite element models of unit cells were used to study the effects of adding TLR on the elastic constants. Parameters investigated included TLR material, TLR volume fraction, TLR diameter, TLR through-thickness angle, ply stacking sequence, and the microstructural features of pure resin regions and curved in-plane fibers. The work was limited to materials with at least one ply interface. Adding a few percent TLR had a small negative effect on the in-plane extensional and shear moduli, E-x, E-y and G(xy), but a large positive effect (up to 60 percent) on the thickness direction extensional modulus, E-z. The volume fraction and the axial modulus of the TLR were the controlling parameters affecting E-z. The out-of-plane shear moduli, G(xz) and G(yz), were significantly affected only with the use of a TLR with a shear modulus an order of magnitude greater than that of the composite lamina. A simple stiffness averaging method for calculating the elastic constants was found to compare closely with the finite element results, with the greatest difference being found in the inter-laminar shear moduli, G(xz) and G(yz). C1 3TEX Inc, Raleigh, NC 27606 USA. NASA, Langley Res Ctr, Army Res Lab, Vehicle Struct Directorate, Hampton, VA 23681 USA. Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23187 USA. RP Dickinson, LC (reprint author), 3TEX Inc, NC State Centennial Campus, Raleigh, NC 27606 USA. NR 27 TC 34 Z9 35 U1 0 U2 5 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 1999 VL 33 IS 11 BP 1002 EP 1029 PG 28 WC Materials Science, Composites SC Materials Science GA 217BF UT WOS:000081478900004 ER PT J AU Bednarcyk, BA Pindera, MJ AF Bednarcyk, BA Pindera, MJ TI Inelastic response of a woven carbon/copper composite, part I: Experimental characterization SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article ID UNIDIRECTIONAL COMPOSITES; SHEAR CHARACTERIZATION; COMPRESSIVE STRENGTH; IMPACT PROPERTIES; TENSION; LAMINATE; FAILURE AB This paper presents the results of an extensive mechanical characterization of a new woven metal matrix composite, namely 8-harness (8H) satin carbon/copper (C/Cu). While woven polymer matrix composites have existed for some time, woven metal matrix composites such as C/Cu are now being developed for the first time. Due to the high thermal conductivity of the copper matrix, this material system is a good candidate for high heat flux applications such as those associated with space power radiator panels and computer chip casings. The mechanical characterization of the 8H satin C/Cu composite was carried out using monotonic and cyclic tension, compression, and Iosipescu shear tests, as well as combined tension-compression tests. Experiments involving applied compression were performed using a novel gripping apparatus not previously described in the open literature. Specimens containing small amounts of chromium and titanium in the copper matrix, in addition to specimens with pure copper matrix, were tested in order to investigate the effect of these alloying elements on the mechanical response. Previous data from thermal expansion and mechanical tests on unidirectional C/Cu composites suggested that the addition of small amounts of these alloying elements to the copper matrix improved the fiber/matrix bond. In addition to the monotonic and cyclic stress-strain response generated using the three types of mechanical tests, a summary of initial moduli, yield stress, and ultimate strength data for this novel woven metal matrix composite is provided and contrasted with the corresponding pure copper data. Further, the presented results provide a basis for validating a new micromechanical model developed by the authors for woven metal matrix composites which is the subject of Parts II and III of this paper. C1 NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. Univ Virginia, Dept Civil Engn & Appl Mech, Charlottesville, VA 22903 USA. RP Bednarcyk, BA (reprint author), NASA, Glenn Res Ctr, Ohio Aerosp Inst, MS 6-1,2100 Brookpk Rd, Cleveland, OH 44135 USA. NR 20 TC 9 Z9 9 U1 2 U2 4 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 1999 VL 33 IS 19 BP 1807 EP 1842 PG 36 WC Materials Science, Composites SC Materials Science GA 254AH UT WOS:000083589000003 ER PT J AU Searles, K Odegard, G Kumosa, M Castelli, M AF Searles, K Odegard, G Kumosa, M Castelli, M TI Failure investigation of graphite/polyimide fabric composites at room and elevated temperatures using the biaxial Iosipescu test SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article ID MIXED-MODE FRACTURE; SHEAR TEST METHOD AB The biaxial and modified biaxial Iosipescu shear test methods were applied to determine the shear dominated, biaxial mechanical response of graphite/PMR-15 and graphite/Avimid-R woven fabric composites at room and elevated temperatures. Three different composite architectures were examined: T650-35 warp-aligned, 8-harness satin (8HS) fabric in a PMR-15 matrix, T650-35 warp-aligned, 8HS fabric in an Avimid-R matrix and T650-35 0 degrees/90 degrees, 8HS fabric in an Avimid-R matrix. Several biaxial Iosipescu tests were performed at room temperature under shear, shear-tension, and shear-compression loading conditions to characterize damage and obtain biaxial, shear dominated failure properties. Shear tests were also conducted at elevated temperatures approaching 316 degrees C to determine the effects of temperature on the shear strengths of the composites investigated. A nonlinear finite element analysis is briefly introduced to evaluate the effects of specimen sliding and geometric nonlinearities on the stress and strain distributions in the biaxial Iosipescu specimens. In addition, the effects of different loading block geometries on the stress distribution in the Iosipescu specimens subjected to biaxial loads were also investigated. Within this investigation, it was found that graphite/Avimid-R was more resistant to biaxial, shear dominated failure at room temperature in comparison to graphite/PMR-15. However, the graphite/PMR-15 composite system exhibited better shear strength properties at elevated temperatures above 232 degrees C. It was also found that the effect of compression along the notch root axis generated by the loading blocks did not affect the loads at failure. C1 Univ Denver, Dept Engn, Denver, CO 80208 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. OI Odegard, Gregory/0000-0001-7577-6565 NR 29 TC 14 Z9 14 U1 1 U2 8 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 1999 VL 33 IS 22 BP 2038 EP 2079 PG 42 WC Materials Science, Composites SC Materials Science GA 264AU UT WOS:000084158100001 ER PT J AU Coats, TW Harris, CE AF Coats, TW Harris, CE TI A progressive damage methodology for residual strength predictions of notched composite panels SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article DE composites; damage; matrix cracks; fiber fracture; internal state variable; residual strength ID LAMINATED COMPOSITES; STRESS-CONCENTRATIONS; FRACTURE; MODEL AB The translaminate fracture behavior of carbon/epoxy structural laminates with through-penetration notches was investigated to develop a residual strength prediction methodology for composite structures. An experimental characterization of several composite materials systems revealed a fracture resistance behavior that resembles the R-curve behavior exhibited by ductile metals. Fractographic examinations led to the postulate that the damage growth resistance was primarily due to fractured fibers in the principal load-carrying plies being bridged by intact fibers of the adjacent plies. The load transfer associated with this bridging mechanism suggests that a progressive damage analysis methodology will be appropriate for predicting the residual strength of laminates with through-penetration notches. A progressive damage methodology developed by the authors was used to predict the initiation and growth of matrix cracks and fiber fracture. The residual strength predictions for different panel widths, notch lengths, and material systems were in reasonable agreement to the experimental failure loads. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Natl Res Council, Washington, DC 20418 USA. RP Harris, CE (reprint author), NASA, Langley Res Ctr, MS-121, Hampton, VA 23681 USA. NR 27 TC 24 Z9 25 U1 0 U2 3 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 1999 VL 33 IS 23 BP 2193 EP 2224 PG 32 WC Materials Science, Composites SC Materials Science GA 362WP UT WOS:000089801500003 ER PT J AU Dickinson, LC Farley, GL Hinders, MK AF Dickinson, LC Farley, GL Hinders, MK TI Translaminar reinforced composites: A review SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Review DE stitched composites; Z-fiber; 3D composites; through-thickness reinforcement AB A trans-laminar-reinforced (TLR) composite may be defined as a composite laminate with up to 5% volume of fibrous reinforcement oriented in a translaminar or through-thickness direction. The TLR can be continuous threads as in stitched laminates, or it can be discontinuous rods or pins as in Z-fiber materials. These materials may be considered a subset of 3D composites, with the distinction that the material structure is a simple layered structure with only a few percent volume of reinforcement through-the-thickness. It has been repeatedly documented in the literature that adding either type of TLR to an otherwise two-dimensional laminate results in the following advantages: substantially improved compression-after-impact response, considerably increased fracture toughness in Mode I (double cantilever beam) and Mode II (end notch flexure), and severely restricted size and growth of impact damage and edge delamination. TLR has also been used to eliminate catastrophic stiffener disbonding in stiffened structures, and in cocured structures it may be used as a substitute for mechanical fasteners. TLR directly protects the Achilles' heel of laminated composites, that is, delamination. As little as 1% volume of TLR significantly alters the mechanical response of laminates. While there is a significant volume of literature, which is reviewed in this paper, there is still a very incomplete understanding of the mechanisms and parameters affecting those mechanisms responsible for the significant changes in the laminate response. C1 3TEX Inc, Raleigh, NC 27606 USA. USA, Res Lab, Vehicle Struct Directorate, NASA,LARC, Hampton, VA 23681 USA. RP Dickinson, LC (reprint author), 3TEX Inc, NC State Centennial Campus, Raleigh, NC 27606 USA. NR 151 TC 29 Z9 31 U1 4 U2 12 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD JAN PY 1999 VL 21 IS 1 BP 3 EP 15 PG 13 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA 159EQ UT WOS:000078159200001 ER PT J AU Balsara, DS Spicer, D AF Balsara, DS Spicer, D TI Maintaining pressure positivity in magnetohydrodynamic simulations SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID HYPERBOLIC CONSERVATION-LAWS; SCHEME AB Higher order Godunov schemes for solving the equations of magnetohydrodynamics (MHD) have recently become available. Because such schemes update the total energy, the pressure is a derived variable. In several problems in laboratory physics, magnetospheric physics, and astrophysics the pressure can be several orders of magnitude smaller than either the kinetic energy or the magnetic energy. Thus small discretization errors in the total energy can produce situations where the gas pressure can become negative. In this paper we design a linearized Riemann solver that works directly on the entropy density equation. We also design switches that allow us to use such a Riemann solver safely in conjunction with a normal Riemann solver for MHD. This allows us to reduce the discretization errors in the evaluation of the pressure variable. As a result we formulate strategies that maintain the positivity of pressure in all circumstances. We also show via test problems that the strategies designedhere work. (C) 1999 Academic Press. C1 Univ Illinois, NCSA, Urbana, IL 61801 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Illinois, NCSA, Urbana, IL 61801 USA. EM dbalsara@ncsa.uiuc.edu; spicer@gauss.gsfc.nasa.gov NR 11 TC 67 Z9 67 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD JAN 1 PY 1999 VL 148 IS 1 BP 133 EP 148 DI 10.1006/jcph.1998.6108 PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 152NL UT WOS:000077783600007 ER PT J AU Bozzolo, G Noebe, RD Ferrante, J Amador, C AF Bozzolo, G Noebe, RD Ferrante, J Amador, C TI An introduction to the BFS method and its use to model binary NiAl alloys SO JOURNAL OF COMPUTER-AIDED MATERIALS DESIGN LA English DT Article DE alloys; BFS method; defect structure; intermetallics; semiempirical methods ID FIRST-PRINCIPLES; INTERATOMIC POTENTIALS; POINT-DEFECTS; CU-AU; UNIVERSAL FEATURES; PHASE-STABILITY; RANGE ORDER; AL ALLOYS; AG-AU; INTERMETALLICS AB We introduce the Bozzolo-Ferrante-Smith (BFS) method for alloys as a computationally efficient tool for aiding in the process of alloy design. An intuitive description of the BFS method is provided, followed by a formal discussion of its implementation. The method is applied to the study of the defect structure of NiAl binary alloys. The groundwork is laid for a detailed progression to higher order NiAl-based alloys linking theoretical calculations and computer simulations based on the BFS method and experimental work validating each step of the alloy design process. C1 Ohio Aerosp Inst, Cleveland, OH 44142 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Cleveland State Univ, Dept Phys, Cleveland, OH 44115 USA. Univ Nacl Autonoma Mexico, Fac Quim, Dept Fis & Quim Teor, Mexico City 04510, DF, Mexico. RP Ohio Aerosp Inst, 22800 Cedar Point Rd, Cleveland, OH 44142 USA. RI Amador-Bedolla, Carlos/E-7448-2010 OI Amador-Bedolla, Carlos/0000-0001-9590-2645 NR 57 TC 25 Z9 25 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0928-1045 J9 J COMPUT-AIDED MATER JI J. Comput-Aided Mater. Des. PY 1999 VL 6 IS 1 BP 1 EP 32 DI 10.1023/A:1026403832705 PG 32 WC Computer Science, Interdisciplinary Applications; Materials Science, Multidisciplinary SC Computer Science; Materials Science GA 336DU UT WOS:000088287300001 ER PT J AU Bozzolo, G Noebe, RD Ferrante, J Garg, A Honecy, FS Amador, C AF Bozzolo, G Noebe, RD Ferrante, J Garg, A Honecy, FS Amador, C TI BFS simulation and experimental analysis of the effect of Ti additions on the structure of NiAl SO JOURNAL OF COMPUTER-AIDED MATERIALS DESIGN LA English DT Article DE alloys; defect structure; heusler phase; intermetallics; semiempirical methods; ternary alloy ID SITE PREFERENCE; INTERMETALLIC COMPOUNDS; DEFECT STRUCTURE; SOLID-SOLUTIONS; POINT-DEFECTS; B2 STRUCTURE; ALLOYS; FEAL; SEGREGATION; CREEP AB The Bozzolo-Ferrante-Smith (BFS) method for alloy energetics is applied to the study of ternary additions to NiAl. A description of the method and its application to alloy design is given. Two different approaches are used in the analysis of the effect of Ti additions to NiAl. First, a thorough analytical study is performed, where: the energy of formation, lattice parameter and bulk modulus are calculated for a large number of possible atomic distributions of Nil Al and Ti. Substitutional site preference schemes and formation of precipitates are thus predicted and analyzed. The second approach used consists of the determination of temperature effects on the final results, as obtained by performing a number of large-scale numerical simulations using the Monte Carlo-Metropolis procedure and BFS for the calculation of the energy at every step in the simulation. The results indicate a sharp preference of Ti for Al sites in Ni-rich NiAl alloys and the formation of ternary Heusler precipitates beyond the predicted solubility limit of 5 at. % Ti. Experimental analysis of three Ni-Al-Ti alleys confirms the theoretical predictions. C1 Ohio Aerosp Inst, Cleveland, OH 44142 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NASA, Lewis Res Ctr, AYT Corp, Cleveland, OH 44135 USA. Univ Nacl Autonoma Mexico, Fac Quim, Dept Fis & Quim Teor, Mexico City 04510, DF, Mexico. RP Ohio Aerosp Inst, 22800 Cedar Point Rd, Cleveland, OH 44142 USA. RI Amador-Bedolla, Carlos/E-7448-2010 OI Amador-Bedolla, Carlos/0000-0001-9590-2645 NR 44 TC 10 Z9 10 U1 1 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0928-1045 J9 J COMPUT-AIDED MATER JI J. Comput-Aided Mater. Des. PY 1999 VL 6 IS 1 BP 33 EP 68 DI 10.1023/A:1026487816775 PG 36 WC Computer Science, Interdisciplinary Applications; Materials Science, Multidisciplinary SC Computer Science; Materials Science GA 336DU UT WOS:000088287300002 ER PT J AU Forsythe, EL Snell, EH Malone, CC Pusey, ML AF Forsythe, EL Snell, EH Malone, CC Pusey, ML TI Crystallization of chicken egg white lysozyme from assorted sulfate salts SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 7th International Conference on Crystallization of Biological Macromolecules CY MAY 03-08, 1998 CL GRANADA, SPAIN DE lysozyme; sulfates; trigonal; monoclinic; crystallization ID DYNAMIC LIGHT-SCATTERING; PROTEIN CRYSTALLIZATION; PHASE-TRANSITION; CRYSTAL-GROWTH; SOLUBILITY; TEMPERATURE; RESOLUTION; EXAMPLE; IONS AB Chicken egg white lysozyme has been found to crystallize from ammonium, sodium, potassium, rubidium, magnesium, and manganese sulfates at acidic and basic pH, with protein concentrations from 60 to 190 mg/ml. Crystals have also been grown at 4 degrees C in the absence of any other added salts using isoionic lysozyme which was titrated to pH 4.6 with dilute sulfuric acid. Four different crystal forms have been obtained, depending upon the temperature, protein concentration, and precipitating salt employed. Crystals grown at 15 degrees C were generally tetragonal, with space group P4(3)2(1)2. Crystallization at 20 degrees C typically resulted in the formation of orthorhombic crystals, space group P2(1)2(1)2(1). The tetragonal <-> orthorhombic transition appeared to be a function of both the temperature and protein concentration, occurring between 15 and 20 degrees C and between 100 and 125 mg/ml protein concentration. Crystallization from 1.2 M magnesium sulfate at pH 7.8 gave a trigonal crystal, space group P3(1)2(1), a = b = 87.4, c = 73.7, gamma = 120 degrees, which diffracted to 2.8 Angstrom. Crystallization from ammonium sulfate at pH 4.6, generally at lower temperatures, was also found to result in a monoclinic form, space group C2, a = 65.6, b = 95.0, c = 41.2, beta = 119.2 degrees. A crystal of similar to 0.2 x 0.2 x 0.5 mm grown from bulk solution diffracted to similar to 3.5 Angstrom. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, Biophys ES76, NAS,NRC Associate, Huntsville, AL 35812 USA. USRA, Huntsville, AL 35806 USA. RP Pusey, ML (reprint author), NASA, George C Marshall Space Flight Ctr, Biophys ES76, NAS,NRC Associate, Huntsville, AL 35812 USA. EM pusey@crystal.msfc.nasa.gov NR 34 TC 25 Z9 26 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JAN PY 1999 VL 196 IS 2-4 BP 332 EP 343 DI 10.1016/S0022-0248(98)00843-4 PG 12 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 161YY UT WOS:000078319200020 ER PT J AU Carter, DC Wright, B Miller, T Chapman, J Twigg, P Keeling, K Moody, K White, M Click, J Ruble, JR Ho, JX Adcock-Downey, L Bunick, G Harp, J AF Carter, DC Wright, B Miller, T Chapman, J Twigg, P Keeling, K Moody, K White, M Click, J Ruble, JR Ho, JX Adcock-Downey, L Bunick, G Harp, J TI Diffusion-controlled crystallization apparatus for microgravity (DCAM): flight and ground-based applications SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 7th International Conference on Crystallization of Biological Macromolecules CY MAY 03-08, 1998 CL GRANADA, SPAIN DE DCAM; protein; crystal; microgravity; Mir; diffusion AB A versatile microdialysis counterdiffusion apparatus was developed in response to special exploratory opportunities for long-duration protein crystal growth experiments presented by the US and Russian Space Program. Challenged to reduce man-tended dependence during this phase, the hardware was designed to eliminate in-flight activation or deactivation. In addition, a disposable interface was incorporated in the design to allow for improved logistics and handling during the pre-flight loading and post-flight distribution of the flight samples for each experiment. The hardware is referred to as the diffusion-controlled crystallization apparatus for microgravity or DCAM (pronounced "dee-cam") which utilizes the dialysis method and allows the equilibration rate of each individual experiment to be passively controlled from several days to several months. Precision control of the rate of approach to supersaturation has routinely produced macro (5 mm to 1.25 cm) crystals for a variety of proteins in this hardware. A description of the hardware and preliminary results from a series of US Shuttle/Mir flight experiments are presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 New Century Pharmaceut Inc, Huntsville, AL 35824 USA. Code ES76 Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Space Res Assoc, Huntsville, AL 35805 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Carter, DC (reprint author), New Century Pharmaceut Inc, 895 Martin Rd, Huntsville, AL 35824 USA. NR 6 TC 27 Z9 30 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JAN PY 1999 VL 196 IS 2-4 BP 602 EP 609 DI 10.1016/S0022-0248(98)00857-4 PG 8 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 161YY UT WOS:000078319200047 ER PT J AU Carter, DC Wright, B Miller, T Chapman, J Twigg, P Keeling, K Moody, K White, M Click, J Ruble, JR Ho, JX Adcock-Downey, L Dowling, T Chang, CH Ala, P Rose, J Wang, BC Declercq, JP Evrard, C Rosenberg, J Wery, JP Clawson, D Wardell, M Stallings, W Stevens, A AF Carter, DC Wright, B Miller, T Chapman, J Twigg, P Keeling, K Moody, K White, M Click, J Ruble, JR Ho, JX Adcock-Downey, L Dowling, T Chang, CH Ala, P Rose, J Wang, BC Declercq, JP Evrard, C Rosenberg, J Wery, JP Clawson, D Wardell, M Stallings, W Stevens, A TI PCAM: a multi-user facility-based protein crystallization apparatus for microgravity SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 7th International Conference on Crystallization of Biological Macromolecules CY MAY 03-08, 1998 CL GRANADA, SPAIN DE PCAM; protein; crystal; microgravity; vapor-diffusion; shuttle ID SINGLE-CRYSTAL GROWTH AB A facility-based protein crystallization apparatus for microgravity (PCAM) has been constructed and flown on a series of Space Shuttle Missions. The hardware development was undertaken largely because of the many important examples of quality improvements gained from crystal growth in the diffusion-limited environment in space. The concept was based on the adaptation for microgravity of a commonly available crystallization tray to increase sample density, to facilitate co-investigator participation and to improve flight logistics and handling. A co-investigator group representing scientists from industry, academia, and government laboratories has been established. Microgravity applications of the hardware have produced improvements in a number of structure-based crystallographic studies and include examples of enabling research. Additionally, the facility has been used to support fundamental research in protein crystal growth which has delineated factors contributing to the effect of microgravity on the growth and quality of protein crystals. (C) 1999 Elsevier Science B.V. All rights reserved. C1 New Century Pharmaceut Inc, Huntsville, AL 35824 USA. George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Dupont Merck Pharmaceut Co, Expt Stn, Wilmington, DE 19880 USA. Univ Georgia, Dept Biochem & Mol Biol, Athens, GA 30602 USA. Catholic Univ Louvain, Lab Chem Phys & Cristallog, B-3000 Louvain, Belgium. Univ Pittsburgh, Dept Biol Sci, Pittsburgh, PA 15260 USA. Eli Lilly & Co, Lilly Corp Ctr, Indianapolis, IN 46285 USA. Washington Univ, Sch Med, Dept Biochem & Mol Biophys, St Louis, MO 63110 USA. Monsanto, Searle BB4K, St Louis, MO 63198 USA. RP Carter, DC (reprint author), New Century Pharmaceut Inc, 895 Martin Rd, Huntsville, AL 35824 USA. NR 20 TC 19 Z9 21 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JAN PY 1999 VL 196 IS 2-4 BP 610 EP 622 DI 10.1016/S0022-0248(98)00858-6 PG 13 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 161YY UT WOS:000078319200048 ER PT J AU Carter, DC Lim, K Ho, JX Wright, BS Twigg, PD Miller, TY Chapman, J Keeling, K Ruble, J Vekilov, PG Thomas, BR Rosenberger, F Chernov, AA AF Carter, DC Lim, K Ho, JX Wright, BS Twigg, PD Miller, TY Chapman, J Keeling, K Ruble, J Vekilov, PG Thomas, BR Rosenberger, F Chernov, AA TI Lower dimer impurity incorporation may result in higher perfection of HEWL crystals grown in microgravity - A case study SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 7th International Conference on Crystallization of Biological Macromolecules CY MAY 03-08, 1998 CL GRANADA, SPAIN DE protein crystals; impurities; microgravity ID EGG-WHITE LYSOZYME; PROTEIN CRYSTALS; REFINEMENT; DYNAMICS; KINETICS AB Crystals of tetragonal hen egg white lysozyme (HEWL) grown on a series of space missions and their terrestrial counterparts were analyzed by gel electrophoresis and X-ray diffraction. The crystals were produced by vapor-diffusion and dialysis methods. The microgravity and terrestrial grown HEWL crystals were found to have effective partitioning coefficients (K-eff) for an oxidatively formed covalent dimer impurity (MW 28 K) of 2 and 9, respectively, i.e. the latter contain 4.5 times more dimers. The microgravity grown crystals allowed the collection of 24% more useful reflections and improved the resolution from 1.6 to 1.35 Angstrom. Other improvements were also noted including lower isotropic B-factors of 16.9, versus 23.8 Angstrom(2) for their terrestrial counterparts. High-resolution laser interferometry was applied quantitatively to evaluate the influence of dimer impurity on growth kinetics. It is shown that the growth of the (1 0 1) face from solution into which 1% dimers were introduced decelerates with increasing solution flow rate and the growth stops at a flow rate of about 0.2 mm/s. This effect occurs faster than in ultrapure solutions. The covalently bound dimers essentially increase the amplitudes of the striation-inducing growth rate fluctuations. The effect is ascribed to the enhanced transport of growth inhibiting HEWL dimer to the interface. Theoretical analysis shows that a stagnant solution around a growing crystal is strongly depleted with respect to impurity by about 60% for the measured growth parameters as compared to the solution bulk. Thus, a crystal in microgravity grows from essentially purer solution than the ones in the presence of convection flows. Therefore, it traps less stress inducing impurity and should be more perfect. For crystal/impurity systems where K-eff is small enough microgravity should have an opposite effect. (C) 1999 Elsevier Science B.V. All rights reserved. C1 New Century Pharmaceut, Huntsville, AL 35824 USA. NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Ctr Micrograv & Mat Res, Huntsville, AL 35899 USA. Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Carter, DC (reprint author), New Century Pharmaceut, 895 Martin Rd, Huntsville, AL 35824 USA. EM dcarter@newcenturypharm.com NR 48 TC 56 Z9 57 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JAN PY 1999 VL 196 IS 2-4 BP 623 EP 637 DI 10.1016/S0022-0248(98)00859-8 PG 15 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 161YY UT WOS:000078319200049 ER PT J AU Choi, SR Gyekenyesi, JP AF Choi, SR Gyekenyesi, JP TI Elevated-temperature "ultra" fast fracture strength of advanced ceramics: An approach to elevated temperature "inert" strength SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT International Gas Turbine and Aeroengine Congress and Exhibition CY JUN 02-05, 1998 CL STOCKHOLM, SWEDEN ID HOT-PRESSED SI3N4; SILICON-NITRIDE; 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 with a series of "ultra" fast test rates. The test materials included four monolithic and one SiC whisker-reinforced composite silicon nitrides. Of the five test materials, four silicon nitrides exhibited the 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 responsible for elevated-temperature failure can be eliminated or minimized by using the "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 Cleveland State Univ, Cleveland, OH 44115 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), Cleveland State Univ, Cleveland, OH 44115 USA. NR 28 TC 10 Z9 10 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD JAN PY 1999 VL 121 IS 1 BP 18 EP 24 DI 10.1115/1.2816306 PG 7 WC Engineering, Mechanical SC Engineering GA 166TC UT WOS:000078592400004 ER PT J AU Lazar, A Rancher, J AF Lazar, A Rancher, J TI Simulation of radionuclide dispersion in the Pacific Ocean from Mururoa atoll SO JOURNAL OF ENVIRONMENTAL RADIOACTIVITY LA English DT Article ID VARIABILITY; MODEL AB A series of numerical simulations was carried out to evaluate, on a Tropical South Pacific scale, the consequences over 10 yr of radionuclide releases to the ocean from French Polynesian nuclear test sites. Tracer advection and diffusion terms were computed based on a dispersion model using ocean dynamics and turbulent mixing coefficients derived from an Ocean General Circulation Model on the basis of a yearly climatological average. Preliminary experiments demonstrated sensitivity of the results to injection depth and type. Two instant unit releases were then carried out at the model characteristic depths of 5 and 364 m: maximum concentrations decrease by factors of more than 10(4) and 10(3), respectively, over 10 yr. Temporal evolution tables for concentrations are given and can be applied to any given quantity of tracer introduced from Mururoa atoll into the Pacific Ocean. Taken as a whole, our results present, from qualitative and quantitative viewpoints, different dispersion scenarios as a function of release characteristics. Finally, a comparison with the surface release study by Ribbe and Tomczak (1990) shows that, while the order of magnitude of tracer concentrations is comparable, the direction of propagation is significantly different. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Paris 06, CNRS, Lab Oceanog Dynam & Climatol, ORSTOM,Unite Mixte Rech, Paris, France. RP Lazar, A (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Code 970, Greenbelt, MD 20771 USA. RI lazar, alban/B-7290-2013 NR 15 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 0265-931X J9 J ENVIRON RADIOACTIV JI J. Environ. Radioact. PY 1999 VL 43 IS 1 BP 31 EP 49 DI 10.1016/S0265-931X(98)00032-0 PG 19 WC Environmental Sciences SC Environmental Sciences & Ecology GA 164DV UT WOS:000078448000003 ER PT J AU Chao, BF Zhou, YH AF Chao, BF Zhou, YH TI Meteorological excitation of interannual polar motion by the North Atlantic Oscillation SO JOURNAL OF GEODYNAMICS LA English DT Article ID ATMOSPHERIC ANGULAR-MOMENTUM; EL-NINO; SOUTHERN OSCILLATION; GEOPOTENTIAL HEIGHT; CHANDLER-WOBBLE; EARTHS WOBBLE; HEMISPHERE; LENGTH; WINTER; TEMPERATURES AB Variations of the atmospheric angular momentum (AAM) is responsible for almost all of the observed length-of-day (LOD) variation on time scales from several days to several years, and much of the observed polar motion on the intra-seasonal time scale. El Nino/Southern Oscillation (ENSO) and Quasi-Biennial Oscillation (QBO) have been singled out to successfully explain interannual LOD variations. However, excitation sources for the interannual polar motion, including the 14 month Chandler wobble, have not been positively identified. This paper studies the correlation of the observed polar motion Psi with the North Atlantic Oscillation (NAO), an interannual, mid-latitude, north-south seesaw in the atmosphere-ocean system. An index (NAOI) used as a proxy to measure the strength of NAO is compared with the observed interannual polar motion excitation during 1964-1994. Cross-correlation functions and coherence spectra demonstrate significant correlations between NAOI and Psi, especially in the x component as expected from NAO's location and general pattern. This constitutes: a positive identification of excitation of interannual polar motion by a meteorological system. Furthermore, our corresponding results with respect to ENSO strongly suggest that a combination of meteorological systems will better explain the observed interannual polar motion and perhaps the Chandler wobble. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Space Geodesy Branch, Greenbelt, MD 20771 USA. Chinese Acad Sci, Shanghai Astron Observ, Shanghai, Peoples R China. RP Chao, BF (reprint author), NASA, Goddard Space Flight Ctr, Space Geodesy Branch, Greenbelt, MD 20771 USA. RI Chao, Benjamin Fong/N-6156-2013 NR 38 TC 12 Z9 13 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD JAN PY 1999 VL 27 IS 1 BP 61 EP 73 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 142QH UT WOS:000077211400004 ER PT J AU Aguero, VM Burke, WJ Gilchrist, BE Stone, NH Gentile, LC Williams, SD Cooke, DL Thompson, DC Bonifazi, C Lebreton, JP AF Aguero, VM Burke, WJ Gilchrist, BE Stone, NH Gentile, LC Williams, SD Cooke, DL Thompson, DC Bonifazi, C Lebreton, JP TI Current collection at the shuttle orbiter during the tethered satellite system tether break SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID TSS-1 AB We present measurements of currents, orbiter potentials, and plasma spectra during high-voltage arcing coincident with the tether break event on the Tethered Satellite System reflight. In addition to the unexpectedly high tether currents observed, plasma spectra indicate the presence of ion and electron populations with broad energy ranges. These data were used, in combination with satellite and orbiter current collection models to investigate the circuit behavior of the system's components. We find that arcing at the lower end of,the tether supported the current flow in the tether during each phase of the break event, but with different mechanisms dominant depending on the location of the break paint. With the break point inside deployer control structures, current arced to the orbiter ground, charging it to high negative potentials and allowing secondary ionization of neutral molecules near orbiter conducting surfaces. The most likely source of these neutrals is air trapped inside the tether at I atm of pressure that escaped through the hole in the tether insulation. When the break point was exposed to the exterior environment the tether current arced directly to the plasma. As long as the break point remained near the orbiter, the collection of electrons by conducting surfaces caused it to float at a low level of negative charging. The source of the energetic elections detected in the payload bay remains uncertain. However, they can only have come from a region within the sheath that was more negatively charged than the orbiter's conducting surfaces. C1 SRI Int, Menlo Park, CA 94025 USA. Agenzia Spaziale Italiana, I-00198 Rome, Italy. USAF, Res Lab, Hanscom AFB, MA 01731 USA. Boston Coll, Inst Sci Res, Chestnut Hill, MA 02467 USA. Space Phys Res Lab, Ann Arbor, MI 48109 USA. European Space Agcy, European Space Res & Technol Ctr, NL-2200 AG Noordwijk, Netherlands. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Utah State Univ, Ctr Atmospher & Space Sci, SER218D, Logan, UT 84322 USA. Stanford Univ, Star Lab, Stanford, CA 94305 USA. RP Aguero, VM (reprint author), SRI Int, 333 Ravenswood Ave,MS-408-95, Menlo Park, CA 94025 USA. EM vaguero@unix.-sri.com; burke@plh.af.mil; gilchrst@eecs.-umich.edu; nobie.stone@-msfc.nasa.gov; gentile@plh.af.mil; scott@nova.stanford.edu; cooke@pepper.plh.af.mil; thompson@demise.cass.usu.edu; bonifazi@asirom.rm.asi.it; jlebreto@estec.esa.nl NR 18 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1999 VL 104 IS A1 BP 105 EP 114 DI 10.1029/1998JA900008 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158LB UT WOS:000078116000009 ER PT J AU Pesnell, WD Goldberg, RA Jackman, CH Chenette, DL Gaines, EE AF Pesnell, WD Goldberg, RA Jackman, CH Chenette, DL Gaines, EE TI A search of UARS data for ozone depletions caused by the highly relativistic electron precipitation events of May 1992 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR PROTON EVENTS; ETALON SPECTROMETER CLAES; MIDDLE ATMOSPHERE; ENERGY DEPOSITION; JULY 13; CYCLE-21; FLUXES AB Highly relativistic electron precipitation (HRE) events containing significant fluxes of electrons with E > 1 MeV have been predicted by models to deplete mesospheric ozone. For the electron fluxes measured during the great HRE of May 1992, depletions were predicted to occur between altitudes of 55 and 80 km, where HOx reactions cause a local minimum in the ozone number density and mixing ratio. Measurements of the precipitating electron fluxes by the particle environment monitor (PEM) tend to underestimate their intensity; thus the predictions of ozone depletion should be considered an estimate of a lower limit. Since the horizontal distribution of the electron precipitation follows the terrestrial magnetic field, it would show a distinct boundary equatorward of the L = 3 magnetic shell and be readily distinguished from material that was not affected by; the HRE precipitation. To search for possible ozone depletion effects, we have analyzed data from the cryogenic limb array etalon spectrometer and microwave limb sounder instruments on UARS for the above HRE. A simplified diurnal model is proposed to understand the ozone data from UARS, also illustrating the limitations of the UARS instruments for seeing the ozone depletions caused by the HRE events. This diurnal analysis limits the relative ozone depletion at around 60 km altitude to values of < 10% during the very intense May 1992 event, consistent with our prediction using ari improved Goddard Space Flight Center two-dimensional model. C1 Nomad Res Inc, Bowie, MD 20716 USA. Lockheed Martin Adv Technol Ctr, Space Phys Dept, Palo Alto, CA 94304 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Pesnell, WD (reprint author), Nomad Res Inc, 2804 Nomad Court, Bowie, MD 20716 USA. EM Pesnell@NomadResearch.com; Richard.A.Goldberg.2@gsfc.nasa.gov; Charles.Jackman@gsfc.nasa.gov; Chenette@spasci.com; Gaines@spasci.com RI Pesnell, William/D-1062-2012; Goldberg, Richard /E-1881-2012; Jackman, Charles/D-4699-2012 OI Pesnell, William/0000-0002-8306-2500; NR 33 TC 9 Z9 9 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1999 VL 104 IS A1 BP 165 EP 175 DI 10.1029/1998JA900030 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158LB UT WOS:000078116000013 ER PT J AU Lakhina, GS Tsurutani, BT AF Lakhina, GS Tsurutani, BT TI A generation mechanism for the polar cap boundary layer broadband plasma waves SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTROSTATIC SOLITARY WAVES; HYBRID DRIFT INSTABILITY; DAYSIDE MAGNETOPAUSE; DIFFUSION-PROCESSES; FREQUENCY WAVES; VELOCITY SHEAR; TURBULENCE; FLUCTUATIONS; MAGNETOTAIL; REGIONS AB Recent Polar observations indicate the presence of broadband plasma waves in the frequency range of similar to 10(1) Hz td about 10(4) Hz on magnetic field Lines mapping into the polar cap boundary layer, at altitudes of about 6 to 8 R-E (where R-E is the Earth radius). These waves are quite similar to the broadband plasma waves observed in the low latitude boundary layer, and they appear to be a mixture of electromagnetic and electrostatic modes. A linear theory for the generation of these waves is developed. The theory is fully electromagnetic and takes into account the free energy available due to the presence of field-aligned currents, and gradients in the currents, plasma densities, and magnetic fields. A generalized dispersion relation for the coupled lower hybrid, whistler, and current convective modes is obtained. It is found; that the presence of density gradients, the current convective modes develop a finite real frequency, but at the same time their growth rates are reduced. On the other hand, sharp density gradients can lead to the excitation of a lower hybrid drift instability when the hat ions are present in the boundary layer. In general, the current convective and lower hybrid drift modes are coupled, and the dispersion relation has to be solved numerically. The inclusion of electromagnetic effects leads to the reduction of the growth rates. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lakhina, GS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Lakhina, Gurbax /C-9295-2012; OI Lakhina, Gurbax /0000-0002-8956-486X NR 48 TC 9 Z9 9 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1999 VL 104 IS A1 BP 279 EP 291 DI 10.1029/98JA02724 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158LB UT WOS:000078116000023 ER PT J AU Fairfield, DH Mukai, T Brittnacher, M Reeves, GD Kokubun, S Parks, GK Nagai, T Matsumoto, H Hashimoto, K Gurnett, DA Yamamoto, T AF Fairfield, DH Mukai, T Brittnacher, M Reeves, GD Kokubun, S Parks, GK Nagai, T Matsumoto, H Hashimoto, K Gurnett, DA Yamamoto, T TI Earthward flow bursts in the inner magnetotail and their relation to auroral brightenings, AKR intensifications, geosynchronous particle injections and magnetic activity SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID KILOMETRIC RADIATION; CURRENT DISRUPTION; MAGNETOSPHERE; DYNAMICS; MODELS; SHEET; FIELD AB High-velocity magnetotail flow bursts measured by the Geotail Low Energy Plasma experiment in the premidnight equatorial region between 10 and 15 R-E have been compared with other magnetospheric phenomena. These bursts, typically characterized by earthward velocities approaching 1000 km/s and lasting for times of the order of 1 min, are associated with magnetotail dipolarizations and large magnetic field fluctuations. Using supporting measurements of the International Solar Terrestrial Physics program it is found that the flow bursts are closely associated with auroral brightenings, AKR onsets, geosynchronous particle injections, and ground magnetic activity. Flow bursts for which Polar UVI images are available showed auroral brightenings that developed near the footpoint Geotail field line. AKR intensifications usually accompanied the flow bursts in close time coincidence, whereas dispersionless geosynchronous particle injections tended to be delayed by 1-3 min. Since flow bursts often exhibit the earliest onsets of these various phenomena, it seems likely that this chain of events is initiated in the tail beyond 15 RE, presumably by magnetic reconnection. It is concluded that flow bursts are a fundamental magnetotail process of limited spacial extent that are important in energy and magnetic flux transport in the magnetosphere. Magnetotail flow bursts are intimately connected to auroral acceleration processes and AKR generation at several thousand kilometer altitude and a full explanation of substorms will have to explain this relationship. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Washington, Geophys Program, Seattle, WA 98195 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Nagoya Univ, STELAB, Toyokawa 442, Japan. Kyoto Univ, Ctr Radio Atmospher Sci, Uji, Kyoto 611, Japan. ISAS, Sagamihara, Kanagawa 229, Japan. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Tokyo Inst Technol, Tokyo 152, Japan. RP Fairfield, DH (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 695, Greenbelt, MD 20771 USA. EM u2dhf@lepdhf.gsfc.nasa.gov; mukai@fujitubo.gtl.isas.ac.jp; brib@geophys.washington.edu; reeves@lanl.gov; kokubun@stelab.nagoya-u.ac.jp; parks@geophys.washington.edu; matsumot@kurasc.kyoto-u.ac.jp; kozo@kurasc.kyoto-u.ac.jp; gurnett@space.physics.uiowa.edu RI Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 35 TC 115 Z9 116 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1999 VL 104 IS A1 BP 355 EP 370 DI 10.1029/98JA02661 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158LB UT WOS:000078116000028 ER PT J AU Berdichevsky, D Thejappa, G Fitzenreiter, RJ Lepping, RL Yamamoto, T Kokubun, S McEntire, RW Williams, DJ Lin, RP AF Berdichevsky, D Thejappa, G Fitzenreiter, RJ Lepping, RL Yamamoto, T Kokubun, S McEntire, RW Williams, DJ Lin, RP TI Widely spaced wave-particle observations during GEOTAIL and Wind magnetic conjunctions in the Earth's ion foreshock with near-radial interplanetary magnetic field SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID UPSTREAM SOLAR-WIND; BOW SHOCK; ACCELERATION; SPACECRAFT; INSTRUMENT; BOUNDARY; EVENTS; PLASMA AB Several events have been identified of an ion foreshock extending up to 250 RE upstream of the Earth. These events occur mostly during periods of slowly drifting radial interplanetary magnetic field (IMF) when the 1-min average values of the strengths of the IMF and the solar wind (SW) speeds are mostly steady. For their analysis an analytical solution to the problem of the closest approach of an IMF line to two spacecraft is given. We used this method to find intervals of magnetic conjunction between the bow shock and the upstream regions at GEOTAIL and Wind. This solution is obtained by determining the minimum angle theta las a function of time) between the mean direction of the IMF (measured at Wind) and the vector-difference (r(WI)-r) of the locations of Wind and the point (attached on the field line) which went earlier by GEOTAIL. Here we take into account the mean drift of the flux lines with the SW, by assuming that the spacecraft were located in the same heliospheric magnetic domain. We have tested this method against a set of selected cases which show a steady presence of the ion foreshock close to the bow shock (GEOTAIL) and its sporadic presence far upstream (Wind). We have found our method to be accurate within a few Earth radii (RE). We have identified an outstanding candidate for the bow shock, GEOTAIL, and Wind sequential magnetic conjunction, which occurred on June 11, 1995. Additionally, this diagnostic technique has been applied to nine more intervals of simultaneous occurrences of intensity enhancements of broadband ultralow-frequency (ULF) waves, and fluctuating fluxes of scattered energetic ions (40-140 keV). Very broad ion foreshock regions (> 40 RE) are commonly observed during the subset of events characterized by a high-speed SW. The observed frequencies of the ULF waves are basically enhanced transversal modes in the range from similar to 1/10 to 2/3 of proton cyclotron frequency, f(CP) Fluctuations in the energetic, ion fluxes were also observed in this frequency range for all the cases. Therefore we argue that the nature of the coupling between ULF waves and energetic ions is similar both in the near as well as far upstream regions of the Earth's bow shock. C1 NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Greenbelt, MD 20771 USA. Nagoya Univ, Solar Terr Environm Lab, Aichi 442, Japan. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Univ Maryland, Dept Astr, College Pk, MD 20742 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. RP Berdichevsky, D (reprint author), NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Code 661, Greenbelt, MD 20771 USA. NR 42 TC 6 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1999 VL 104 IS A1 BP 463 EP 482 DI 10.1029/1998JA900018 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158LB UT WOS:000078116000036 ER PT J AU Steffen, K Abdalati, W Sherjal, I AF Steffen, K Abdalati, W Sherjal, I TI Faceted crystal formation in the northeast Greenland low-accumulation region SO JOURNAL OF GLACIOLOGY LA English DT Article ID ICE-SHEET; DEPTH-HOAR; SNOW; GROWTH; TEMPERATURE AB Snow-pit analysis in the low-accumulation region in northeast Greenland indicated a mean annual accumulation of 12 +/- 1.6 cm. It also revealed numerous faceted layers that were not related to the summer horizon of previous years. In general, the faceted crystals were found under a wind crust. These crusts appear to originate during the winter. Snow- and air-temperature data from automatic weather stations suggest that the katabatic storms are responsible for the formation of the wind crusts and the faceted layers. Frequent, abrupt temperature changes up to 30 degrees C were observed within two days, due to turbulent mixing of cold-air inversions. The near-surface air-temperature variations are correlated with wind speed, the latter leading the former by 6-9 hours for increasing wind, and 1-4 hours for decreasing wind. Because of low accumulation, katabatic storms affect the same snow surface for several months, causing repeated air-temperature fluctuations. This leads to strong vapor-pressure gradients and faceted crystal growth in the top snow layer On average we found two faceted layers (in addition to the summer layer) per year for a 1 year record. In addition to its climatological significance in the snow record, the formation of these layers is especially important to understand for the interpretation of microwave satellite observations of the firn. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Ctr Study Earth Space, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Steffen, K (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Ctr Study Earth Space, Campus Box 216, Boulder, CO 80309 USA. RI Steffen, Konrad/C-6027-2013 OI Steffen, Konrad/0000-0001-8658-1026 NR 28 TC 14 Z9 14 U1 0 U2 1 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 1999 VL 45 IS 149 BP 63 EP 68 PG 6 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 193LX UT WOS:000080138700008 ER PT J AU Michel, R Rignot, E AF Michel, R Rignot, E TI Flow of Glaciar Moreno, Argentina, from repeat-pass Shuttle Imaging Radar images: comparison of the phase correlation method with radar interferometry SO JOURNAL OF GLACIOLOGY LA English DT Article ID SOUTHERN PATAGONIA ICEFIELD; SURFACE-PROPERTIES; SATELLITE; AMERICA; DYNAMICS AB High-resolution radar images of Glaciar Moreno, Argentina, acquired by the Shuttle Imaging Radar C (SIR-C) on 9 and 10 October 1994 at 24 cm wavelength (L-band), are utilized to map the glacier velocity both interferometrically and using the phase correlation method. The precision of the interferometric ice velocities is 1.8 cm d(-1) (6 m a(-1)) (1 sigma). The phase correlation method measures ice velocity with a precision of 14 cm d(-1) (50 m a(-1)) with image data at a 6 m sample spacing acquired 1 day apart. Averaged strain rates are measured with a precision of 10(-4) d(-1) at a 240 m sample spacing with the phase correlation method, and 10(-5) d(-1) with radar interferometry. The phase correlation method is less precise than radar interferometry, but it performs better in areas of rapid flow, is more robust to temporal changes in glacier scattering and measures the glacier velocity in two dimensions with only one image pair. Using this technique, we find that Glaciar Moreno flows at 400 m a(-1) in the terminal valley and 800 m a(-1) at the calving front, in agreement with velocities recorded a decade ago. Assuming steady-state now conditions, the vertical strain rates measured by SIR-C are combined with prior data on mass ablation to estimate the glacier thickness and ice discharge. The calculated discharge is 0.6 +/- 0.2 km(3) ice a(-1) at 300 m elevation, and 1.1 +/- 0.2 km3 ice a(-1) at the equilibrium-line elevation (1150 m), which yields a balance accumulation of 6 +/- 1 m ice a(-1). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Michel, R (reprint author), CEA, Geophys Lab, BP 12, F-91680 Bruyeres Le Chatel, France. RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 24 TC 95 Z9 100 U1 0 U2 4 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 1999 VL 45 IS 149 BP 93 EP 100 PG 8 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 193LX UT WOS:000080138700011 ER PT J AU Joughin, I Fahnestock, M Kwok, R Gogineni, P Allen, C AF Joughin, I Fahnestock, M Kwok, R Gogineni, P Allen, C TI Ice flow of Humboldt, Petermann and Ryder Gletscher, northern Greenland SO JOURNAL OF GLACIOLOGY LA English DT Article ID SATELLITE RADAR INTERFEROMETRY; SHEET MOTION; GLACIER; ACCUMULATION; TOPOGRAPHY; DYNAMICS; VELOCITY; MODEL AB Radar interferometry, ice-penetrating radar profiles and an elevation model are used to determine the velocity fields, rates of ice discharge, approximate states of balance and catchment area for three large outlet glaciers in northeast Greenland. Discharge through flux gates is calculated for Humboldt and Petermann Gletscher, which are found to be in balance (at the level that the accumulation is known). A large difference between the measured and estimated fluxes for Ryder Gletscher may be a reflection of unsteady flow behavior for this glacier. The patterns of ice flow for the three glaciers considered are each unique, showing that the nature of ice discharge varies substantially from basin to basin, controlled by bed conditions and the presence of subglacial troughs and obstructions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland, Dept Meteorol, Joint Ctr Earth Syst Sci, College Pk, MD 20742 USA. Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. RP Joughin, I (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kwok, Ron/A-9762-2008; Joughin, Ian/A-2998-2008; Fahnestock, Mark/N-2678-2013 OI Kwok, Ron/0000-0003-4051-5896; Joughin, Ian/0000-0001-6229-679X; NR 33 TC 18 Z9 19 U1 1 U2 6 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 1999 VL 45 IS 150 BP 231 EP 241 DI 10.3189/002214399793377284 PG 11 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 229QA UT WOS:000082205000006 ER PT J AU Forster, RR Rignot, E Isacks, BL Jezek, KC AF Forster, RR Rignot, E Isacks, BL Jezek, KC TI Interferometric radar observations of Glaciares Europa and Penguin, Hielo Patagonico Sur, Chile SO JOURNAL OF GLACIOLOGY LA English DT Article ID ICE-SHEET MOTION; SOUTHERN PATAGONIA; SATELLITE; GREENLAND; GLACIER; TOPOGRAPHY; ICEFIELD; DYNAMICS; MORENO AB Repeat-pass L-band interferometric synthetic aperture radar (InSAR) data for part of Hielo Patagonico Sur, Chile, were collected by the space-shuttle-based Spaceborne Imaging Radar C (SIR-C) over a 4 day span in October 1994. Three co-registered complex SAR images are used to generate phase-coherence maps, a digital elevation model (DEM) and an ice-velocity map. The phase-coherence maps indicate low coherence in the 5-15 km approaching the termini due to large displacements, ice deformation and melting. However, the coherence is high over nearly all of the remaining imaged icefield. Ice-velocity precision is greater than 2 cm d(-1) while the DEM is good to about 25 m. A flow divide between two of the glaciers is mapped by locating a narrow band of near-zero ice velocity. Horizontal ice-surface velocity profiles calculated along flowlines show there is a high degree of spatial variability reaching a peak value of 5.5 m d(-1) located 3.5 km from the terminus of Glaciar Europa. Longitudinal strain rates along the center lines calculated from these velocities at the locations of the initiation of crevassing are used to compute the tensile strength of ice (169-224 kPa). C1 Cornell Univ, Dept Geol Sci, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. RP Forster, RR (reprint author), Univ Utah, Dept Geog, Salt Lake City, UT 84112 USA. RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 44 TC 19 Z9 19 U1 1 U2 3 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 1999 VL 45 IS 150 BP 325 EP 337 DI 10.3189/002214399793377220 PG 13 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 229QA UT WOS:000082205000015 ER PT J AU Pappa, RS AF Pappa, RS TI Independent analysis of the space station node modal test data SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID EIGENSYSTEM REALIZATION-ALGORITHM; IDENTIFICATION AB With complex structures, comparison of independently derived sets of experimental modal parameters is an excellent way to increase confidence in the results. Modal identification results are presented using the eigensystem realization algorithm on frequency response functions from the modal test of the space station resource node. The resource node is the first U.S.-built structure for the International Space Station. The modal test was conducted by the NASA Marshall Space Flight Center in January 1997 for The Boeing Company, who designed and built the node. The calculated parameters are compared with independent results obtained by the test team using commercial software. There was excellent correlation of mode shapes between the two sets of results for the first 21 vibration modes of the structure up to 35 Hz. From 35 to 50 Hz, about 60% of 25 additional modes had excellent correlation. Natural frequencies and damping factors of most modes agreed within 0.1 Hz and 0.2%, respectively. C1 NASA, Struct Dynam Branch, Struct Div, Langley Res Ctr, Hampton, VA 23681 USA. RP Pappa, RS (reprint author), NASA, Struct Dynam Branch, Struct Div, Langley Res Ctr, Hampton, VA 23681 USA. NR 9 TC 3 Z9 4 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1999 VL 22 IS 1 BP 22 EP 27 DI 10.2514/2.4366 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 157WB UT WOS:000078083700002 ER PT J AU Wang, PKC Hadaegh, FY Lau, K AF Wang, PKC Hadaegh, FY Lau, K TI Synchronized formation rotation and attitude control of multiple free-flying spacecraft SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB In the observation slewing of long baseline interferometers formed by multiple free-flying spacecraft in formation, it is required to rotate the entire formation about a given axis and to synchronize individual spacecraft rotation with formation rotation. Using a particle model for spacecraft formation dynamics and a rigid-body model for spacecraft attitude dynamics, control laws are derived for this mode of operation in the absence of a gravitational field and disturbances. A simplified control law suitable for implementation is also obtained. It is shown that under mild conditions the formation alignment error decays to zero exponentially with time. Computer simulation studies are made far a free-flying spacecraft triad in a triangular formation. The results show that the developed control laws are effective in synchronized formation rotation. C1 Univ Calif Los Angeles, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, PKC (reprint author), Univ Calif Los Angeles, Los Angeles, CA 90095 USA. NR 10 TC 116 Z9 129 U1 0 U2 8 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1999 VL 22 IS 1 BP 28 EP 35 DI 10.2514/2.4367 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 157WB UT WOS:000078083700003 ER PT J AU Boyle, DP Chamitoff, GE AF Boyle, DP Chamitoff, GE TI Autonomous maneuver tracking for self-piloted vehicles SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID INVERSE SIMULATION; AIRCRAFT MANEUVERS; FLIGHT AB A fully autonomous flight vehicle must be capable of accurately tracking a desired trajectory far the safe and effective completion of a given mission. An approach to maneuver autopilot design is presented based on a six-degree-of-freedom nonlinear trimming algorithm coupled with a robust tracking controller Acceleration commands required for closed-loop tracking of a desired trajectory in an Earth-fixed reference frame are provided by a simple guidance strategy. The trimming algorithm generates optimal state commands and feedforward controls to accomplish the maneuver, while assuring that these commands fan be tracked by an inner-loop controller without violating vehicle performance or actuator constraints. This approach is demonstrated in simulated flight of an actual fixed-wing uninhabited aerial vehicle, named Ariel. Excellent tracking performance is achieved for a representative three-dimensional trajectory using a high-fidelity aircraft model with nonlinear dynamics and realistic wind gust disturbances. In addition, an analysis of system robustness to uncertainty in the vehicle model is performed. C1 Univ Sydney, Dept Aeronaut Engn, Sydney, NSW 2006, Australia. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Boyle, DP (reprint author), Univ Sydney, Dept Aeronaut Engn, Sydney, NSW 2006, Australia. NR 22 TC 17 Z9 17 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1999 VL 22 IS 1 BP 58 EP 67 DI 10.2514/2.4371 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 157WB UT WOS:000078083700007 ER PT J AU Goodson, T Chuang, JCH Hanson, J AF Goodson, T Chuang, JCH Hanson, J TI Optimal finite thrust orbit transfers with large numbers of burns SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID DIFFERENTIAL INCLUSION; DIRECT TRANSCRIPTION; COLLOCATION AB This paper presents new theoretical results that are used to construct a new algorithm for the computation of fuel-optimal multiple-burn orbit transfers of low and medium thrust. Intuitively, one might want to think of an optimal multiple-burn transfer problem not as one large trajectory problem but as a sequence of optimal one-burn transfers between intermediate orbits that are optimally chosen. For spherical-body gravity, a strong relationship is shown to exist between these two problems. Theoretical results are used to transform the traditional set of necessary conditions to an equivalent set of conditions. Based on these results, a new numerical method that iteratively computes optimal orbit transfers is presented. Numerical results for an 11-burn transfer are presented to demonstrate the new algorithm. C1 Georgia Inst Technol, Atlanta, GA 30332 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Goodson, T (reprint author), Georgia Inst Technol, Atlanta, GA 30332 USA. NR 27 TC 6 Z9 7 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1999 VL 22 IS 1 BP 139 EP 148 DI 10.2514/2.4360 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 157WB UT WOS:000078083700016 ER PT J AU Miyoshi, K AF Miyoshi, K TI Space tribology developments in the USA - Today and tomorrow SO JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS LA Japanese DT Article DE space tribology; space mechanisms; lubricants; surface engineering; coatings and thin films C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Miyoshi, K (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 10 TC 0 Z9 0 U1 1 U2 3 PU JAPAN SOC TRIBOLOGISTS PI TOKYO PA KIKAI SHINKO KAIKAN NO 407-2 5-8 SHIBA-KOEN 3-CHOME MINATO-KU, TOKYO, 105, JAPAN SN 0915-1168 J9 J JPN SOC TRIBOLOGIS JI J. Jpn. Soc. Tribol. PY 1999 VL 44 IS 5 BP 320 EP 326 PG 7 WC Engineering, Mechanical SC Engineering GA 212HY UT WOS:000081212300009 ER PT J AU Kaur, I Grimm, EA Pierson, DL AF Kaur, I Grimm, EA Pierson, DL TI Effect of spaceflight on the functions of NK and LAK cells. SO JOURNAL OF LEUKOCYTE BIOLOGY LA English DT Meeting Abstract C1 Enterprise Advisory Serv Inc, Houston, TX USA. Univ Texas, MD Anderson Canc Ctr, Houston, TX 77030 USA. NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0741-5400 J9 J LEUKOCYTE BIOL JI J. Leukoc. Biol. PY 1999 SU S MA 13 BP 11 EP 11 PG 1 WC Cell Biology; Hematology; Immunology SC Cell Biology; Hematology; Immunology GA 225QX UT WOS:000081973200013 ER PT J AU Zhong, F Meyer, H AF Zhong, F Meyer, H TI Heat transport in a pure fluid near the critical point: Steady state and relaxation dynamics SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article ID VAPOR CRITICAL-POINT; THAN-T-C; TEMPERATURE PROPAGATION; DENSITY EQUILIBRATION; THERMAL-CONDUCTIVITY; HE-3; GRAVITY; MICROGRAVITY; HELIUM AB The steady-slate conditions and relaxation dynamics of a fluid layer during heat transport experiments near the liquid-vapor critical point are studied theoretically. The application is to He-3 along the critical isochore and under normal gravity-where experimental data are available-as well as zero gravity. First, the steady-state density stratification from gravity and from heat flow is calculated The resulting observable thermal conductivity <(lambda)over bar>(obs) is obtained as a function of the temperature difference Delta T (or the heat current Q) across the fluid layer and becomes a strong non-linear function of Delta T as T-c is approached The calculated <(lambda)over bar>(obs) is compared with that from experiments both above and below T-c. Second, the spatial profiles of temperature and density and their temporal evolutions are calculated above T-c as Delta T is established after Q is switched on, or conversely as Delta T decays to zero after Q has been switched off From the calculations, done both from a closed-form expression and from simulations, the "observable" and "asymptotic" relaxation times for reaching the steady state are calculated as a function of Q, and compared with the experiments above T-c. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Duke Univ, Dept Phys, Durham, NC 27708 USA. RP Zhong, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 28 TC 5 Z9 5 U1 1 U2 2 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD JAN PY 1999 VL 114 IS 1-2 BP 231 EP 255 DI 10.1023/A:1021862122617 PG 25 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 157TD UT WOS:000078077000009 ER PT J AU Li, FM Huang, LY Shi, Y Jin, XG Wu, ZQ Shen, ZH Chuang, K Lyon, RE Harris, FW Cheng, SZD AF Li, FM Huang, LY Shi, Y Jin, XG Wu, ZQ Shen, ZH Chuang, K Lyon, RE Harris, FW Cheng, SZD TI Thermal degradation mechanism and thermal mechanical properties of two high-performance aromatic polyimide fibers SO JOURNAL OF MACROMOLECULAR SCIENCE-PHYSICS LA English DT Article ID ORGANO-SOLUBLE POLYIMIDES; FILMS; DIANHYDRIDE; POLYMERIZATION AB Two organo-soluble aromatic polyimides have been synthesized by introducing pendant groups of trifluromethyl or methyl onto the 2- and 2'-positions of a biphenyl diamine and reacting each of them with biphenyltetracarboxylic dianhydride (BPDA): 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (PFMB) or 2,2'-dimethyl-4,4'-diaminobiphenyl (DMB). These two polyimides, BPDA-PFMB and BPDA-DMB, are prepared via a one-step polycondensation method, and they can be fabricated into fibers, films, and other application forms. Our research shows that in fiber applications, these two fibers exhibit excellent mechanical properties and outstanding thermal and thermooxidative stability. Their longterm mechanical tensile performance at high temperatures is found to be critically associated with the type of side pendant groups at the 2- and 2'-positions of the diamines. High-resolution pyrolysis-gas chromatography/mass spectrometry (PyGC-MS) results show that the pyrorgams of these two polyimides possess more than 16 pyrolyzates. Based on the compositions and distributions of the pyrolyzates at different temperatures, the thermal degradation mechanisms for both of the polyimides are found to be the same. C1 Chinese Acad Sci, Inst Chem, Beijing 100080, Peoples R China. Univ Akron, Maurince Morton Inst, Akron, OH 44325 USA. Univ Akron, Dept Polymer Sci, Akron, OH 44325 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Atlantic City Int Airport, Fed Aviat Adm, Fire Res Branch, Atlantic City, NJ 08405 USA. RP Cheng, SZD (reprint author), Chinese Acad Sci, Inst Chem, Beijing 100080, Peoples R China. NR 24 TC 15 Z9 17 U1 2 U2 13 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 USA SN 0022-2348 J9 J MACROMOL SCI PHYS JI J. Macromol. Sci.-Phys. PY 1999 VL B38 IS 1-2 BP 107 EP 122 DI 10.1080/00222349908248109 PG 16 WC Polymer Science SC Polymer Science GA 183FF UT WOS:000079543000009 ER PT J AU Danks, RA AF Danks, RA TI Management and a load of hot air SO JOURNAL OF MANAGEMENT IN ENGINEERING LA English DT Editorial Material C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Danks, RA (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0742-597X J9 J MANAGE ENG JI J. Manage. Eng. PD JAN-FEB PY 1999 VL 15 IS 1 BP 7 EP 7 PG 1 WC Engineering, Industrial; Engineering, Civil SC Engineering GA 147JE UT WOS:000077565400009 ER PT J AU Ivchenko, VO Krupitsky, AE Kamenkovich, VM Wells, NC AF Ivchenko, VO Krupitsky, AE Kamenkovich, VM Wells, NC TI Modeling the Antarctic circumpolar current: A comparison of FRAM and equivalent barotropic model results SO JOURNAL OF MARINE RESEARCH LA English DT Article ID GENERAL-CIRCULATION MODEL; OCEAN CIRCULATION; SOUTHERN-OCEAN AB Analyzing the FRAM simulations, Kinworth (1992) noticed a strong tendency for self-similarity in the vertical structure of the velocity field of the Antarctic Circumpolar Current (ACC). By assuming the self-similarity as a hypothesis, Krupitsky et al. (1996) developed an equivalent barotropic (EB) model of the ACC capable of describing the horizontal structure of the ACC. Compared to the multi-level-primitive-equation GCM, the EB model appeared substantially simpler and therefore useful in pilot process-oriented and sensitivity studies. In the present study dynamical and kinematical comparisons of the EB and FRAM outputs are given. C1 Univ Southampton, Dept Oceanog, Southampton S014 3ZH, Hants, England. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, MS 39529 USA. RP Ivchenko, VO (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 11 Z9 11 U1 0 U2 1 PU KLINE GEOLOGY LABORATORY PI NEW HAVEN PA YALE UNIV, NEW HAVEN, CT 06520-8109 USA SN 0022-2402 J9 J MAR RES JI J. Mar. Res. PD JAN PY 1999 VL 57 IS 1 BP 29 EP 45 DI 10.1357/002224099765038553 PG 17 WC Oceanography SC Oceanography GA 173AT UT WOS:000078959300002 ER PT J AU Zhu, DM Miller, RA AF Zhu, DM Miller, RA TI Determination of creep behavior of thermal barrier coatings under laser imposed high thermal and stress gradient conditions SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID RELAXATION; ZIRCONIA; FATIGUE AB A laser sintering/creep technique has been established to determine the creep behavior of thermal barrier coatings under steady-state high heat flux conditions. For a plasma sprayed zirconia-g wt. % yttria coating, a significant primary creep strain and a low apparent creep activation energy were observed. Possible creep mechanisms involved include stress induced mechanical sliding and temperature and stress enhanced cation diffusion through the splat and grain boundaries. The elastic modulus evolution, stress response, and total accumulated creep strain variation across the ceramic coating are simulated using a finite difference approach. The modeled creep response is consistent with experimental observations. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 36 TC 36 Z9 37 U1 0 U2 7 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD JAN PY 1999 VL 14 IS 1 BP 146 EP 161 DI 10.1557/JMR.1999.0023 PG 16 WC Materials Science, Multidisciplinary SC Materials Science GA 168PG UT WOS:000078701000023 ER PT J AU Aglan, H Gan, Y El-Hadik, M Faughnan, P Bryan, C AF Aglan, H Gan, Y El-Hadik, M Faughnan, P Bryan, C TI Evaluation of the fatigue fracture resistance of unfilled and filled polytetrafluoroethylene materials SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID STYRENE BLOCK-COPOLYMERS; ADHESIVE JOINTS; AMORPHOUS POLYMERS; COMPOSITES; TOUGHNESS; BEHAVIOR; STRENGTH; MECHANISMS; ENERGIES; FAILURE AB Polytetrafluoroethylenes (PTFEs) and their composites are a special class of fluorocarbons with very high chemical resistance and wide service temperature. This makes them good candidate materials for load-bearing components exposed to harsh environments, including some space applications. In the present work, fatigue crack propagation (FCP) behavior of four materials from the fluorocarbon family, including PTFE without filler (virgin PTFE), PTFE with 15% glass fiber, PTFE with '15% graphite particles, and PTFE with 25% glass fiber, were studied. Tension/tension FCP experiments were carried out using single-edge notch (SEN) specimens under load control. The maximum stress was kept constant at 8 MPa for each material at a frequency of 3 Hz. The minimum to maximum stress ratio was 0.27. FCP data such as the number of cycles, crack length, and hysteresis loops were recorded in order to establish the crack speed, the energy release rate, J*, and the change in work (W) over dot (i). Parameters that characterize the resistance of PTFEs to FCP have been successfully determined by the modified crack layer (MCL) model. These parameters are gamma', the specific energy of damage, which reflects the FCP resistance of the PTFE materials, and the dissipative characteristic of the materials, beta'. It has been found that the MCL model describes the behavior of the PTFEs over the entire range of the energy release rate and discriminates the subtle effects introduced by changing the filler type and dosage as well as the processing conditions. The values of the specific energy of damage gamma' have been found to decrease by increasing the dosage of the fiberglass fillers. Graphite particulate filler also reduced the value of gamma' more than fiberglass filler for the same dosage. Microscopic analysis of the fracture surface in the stable crack propagation region of each material revealed that there exists a strong correlation between the value of gamma' and the amount of damage energy manifested by different mechanisms and species during the fatigue process. (C) 1999 Kluwer Academic Publishers. C1 Tuskegee Univ, Dept Engn Mech, Tuskegee, AL 36088 USA. NASA, Kennedy Space Ctr, FL USA. RP Aglan, H (reprint author), Tuskegee Univ, Dept Engn Mech, Tuskegee, AL 36088 USA. NR 57 TC 29 Z9 34 U1 2 U2 13 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD JAN 1 PY 1999 VL 34 IS 1 BP 83 EP 97 DI 10.1023/A:1004465507788 PG 15 WC Materials Science, Multidisciplinary SC Materials Science GA 173GE UT WOS:000078972100012 ER PT J AU Choi, SR Gyekenyesi, JP AF Choi, SR Gyekenyesi, JP TI Slow crack growth analysis of brittle materials with finite thickness subjected to constant stress-rate flexural loading SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID DYNAMIC FATIGUE; INDENTATION FLAWS; GLASS AB A two-dimensional, numerical analysis of slow crack growth (SCG) was performed for brittle materials with finite thickness subjected to constant stress-rate ("dynamic fatigue") loading in flexure. The numerical solution showed that the conventional, simple, one-dimensional analytical solution can be used with a maximum error of about 5% in determining the SCG parameters of a brittle material with the conditions of a normalized thickness (a ratio of specimen thickness to initial crack size) T > 3.3 and of a SCG parameter n greater than or equal to 10. The change in crack shape from semicircular to elliptical configurations was significant particularly at both low stress rate and low T, attributed to predominant difference in stress intensity factor along the crack front. The numerical solution of SCG parameters was supported within the experimental range by the data obtained from constant stress-rate flexural testing for soda-lime glass microslides at ambient temperature. (C) 1999 Kluwer Academic Publishers. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Cleveland State Univ, Cleveland, OH 44115 USA. RP Choi, SR (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 20 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PY 1999 VL 34 IS 16 BP 3875 EP 3882 DI 10.1023/A:1004618722388 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 223DM UT WOS:000081825100005 ER PT J AU Kleiner, I Brown, LR Tarrago, G Kou, QL Picque, N Guelachvili, G Dana, V Mandin, JY AF Kleiner, I Brown, LR Tarrago, G Kou, QL Picque, N Guelachvili, G Dana, V Mandin, JY TI Positions and intensities in the 2 nu(4)/nu(1)/nu(3) vibrational system of (NH3)-N-14 near 3 mu m SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID FREQUENCY MEASUREMENTS; INFRARED INTENSITIES; FOURIER-TRANSFORM; CARS SPECTROSCOPY; ENERGY-LEVELS; AMMONIA; NH3; MOLECULES; SPECTRA; MOMENT AB Line positions and line intensities of the nu(1), nu(3), and 2 nu(4) bands of (NH3)-N-14 were analyzed using line positions from 0.0054 cm(-1) apodized resolution FT spectra recorded at Orsay and using line intensities from 0.011 cm(-1) unapodized resolution FT spectra recorded at Kitt Peak National Observatory. About 2110 lines with J' w less than or equal to 10 were assigned from which 1832 line positions were fitted using an effective rotation-inversion Hamiltonian to achieve an rms of 0.085 cm(-1), Nearly 1000 line intensities were measured with an accuracy of 6% or better and modeled to 11 terms of dipole moment expansion to +/-9.4%. The bandstrengths of the nu(1), nu(3), and 2 nu(4) bands (determined for the first time in the case of the 2 nu(4) band) are, respectively, 23.6(2), 11.8(1), and 2.82(4) cm(-2)/atm at 296 K. A prediction of the line positions and intensities was generated for some similar to 2700 lines with intensities calculated greater than 1 x 10(-4) cm(-2) atm(-1) at 296 K, suitable for planetological purposes. Tentative assignments involving 22 upper state levels of 4 nu(2)(s) were identified, but these were not included in the modeling at the present stage. The theoretical model and the set of programs developed for treating the infrared system nu(1)/nu/2 nu(4) of ammonia are briefly discussed. (C) 1999 Academic Press. C1 Univ Paris Sud, Photophys Mol Lab, CNRS, Unite Propre, F-91405 Orsay, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Paris Sud, Lab Phys Mol & Applicat, F-91405 Orsay, France. Univ Paris 06, Lab Phys Mol & Applicat, F-75252 Paris 05, France. RP Kleiner, I (reprint author), Univ Paris Sud, Photophys Mol Lab, CNRS, Unite Propre, Batiment 213, F-91405 Orsay, France. NR 30 TC 76 Z9 76 U1 0 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JAN PY 1999 VL 193 IS 1 BP 46 EP 71 DI 10.1006/jmsp.1998.7728 PG 26 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 151JT UT WOS:000077717500005 ER PT J AU Subbarao, GV Wheeler, RM Stutte, GW Levine, LH AF Subbarao, GV Wheeler, RM Stutte, GW Levine, LH TI How far can sodium substitute for potassium in red beet? SO JOURNAL OF PLANT NUTRITION LA English DT Article ID SALT STRESS; GLYCINEBETAINE; ACCUMULATION AB Sodium (Na) movement between plants and humans is one of the more critical aspects of bioregenerative systems of life support, which NASA is studying for the establishment of long-term bases on the Lunar or Martian surface. This study was conducted to determine the extent to which Na can replace potassium (K) in red beet (Beta vulgaris L. ssp vulgaris) without adversely affecting metabolic functions such as water relations, photosynthetic rates, and thus growth. Two cultivars, Ruby Queen and Klein Bol,were grown fbr 42 days at 1200 mu mol mol(-1) CO2 in a growth chamber using a re-circulating nutrient film technique with 0%, 75%, 95%, and 98% Na substitution for K in a modified half-strength Hoagland solution. Total biomass of Ruby Queen was greatest at 95% Na substitution and equal at 0% and 98% Na substitution. For Klein Bol, there was a 75% reduction in total biomass at 98% Na substitution. Nearly 95% of the total plant K was replaced with Na at 98% Na substitution in both cultivars. Potassium concentrations in leaves decreased from 120 g kg(-1) dwt in 0% Na substitution to 3.5 g kg(-1) dwt at 98% Na substitution. Leaf chlorophyll concentration, photosynthetic rate, and osmotic potential were not affected in either cultivar by Na substitution for K. Leaf glycinebetaine levels were doubled at 75% Na substitution in Klein Bol, but decreased at higher levels of Na substitution. For Ruby Queen, glycinebetaine levels in leaf increased with the first increase of Na levels and were maintained at the higher Na levels. These results indicate that in some cultivars of red beet, 95% of the normal tissue K can be replaced by Na without a reduction in growth. C1 US Natl Res Council, Kennedy Space Ctr, FL 32899 USA. NASA, Biomed Off, Kennedy Space Ctr, FL 32899 USA. Dynamac Corp, Kennedy Space Ctr, FL 32899 USA. RP Subbarao, GV (reprint author), US Natl Res Council, Kennedy Space Ctr, FL 32899 USA. NR 40 TC 37 Z9 42 U1 1 U2 10 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 USA SN 0190-4167 J9 J PLANT NUTR JI J. Plant Nutr. PY 1999 VL 22 IS 11 BP 1745 EP 1761 DI 10.1080/01904169909365751 PG 17 WC Plant Sciences SC Plant Sciences GA 247HN UT WOS:000083215500007 PM 11542657 ER PT J AU Bain, DB Smith, CE Liscinsky, DS Holdeman, JD AF Bain, DB Smith, CE Liscinsky, DS Holdeman, JD TI Flow coupling effects in jet-in-crossflow flowfields SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 32nd Joint Propulsion Conference CY JUL 01-03, 1996 CL LAKE BUENA VISTA, FLORIDA SP Amer Inst Aeronaut & Astronaut, ASME, SAE, ASEE ID DILUTION AB The combustor designer is typically required to design liner orifices that effectively mix airjets with crossflow effluent. Computational fluid dynamics (CFD) combustor analysis is typically used in the design process; however, the jets are usually assumed to enter the combustor with a uniform velocity and turbulence profile. The jet-mainstream flow coupling is usually neglected because of the computational expense. This study was performed to understand the effect of jet and mainstream how coupling, and to investigate jet boundary conditions that are commonly used in combustor internal calculations. A case representative of a plenum-fed quick-mix section of a rich burn/quick mix/lean burn combustor, i.e,, a jet to mainstream mass-how ratio of about 3 and a jet to mainstream momentum-flux ratio of about 30, was investigated. This case showed that the jet velocity entering the combustor nas very nonuniform, with a low normal velocity at the leading edge of the orifice and a high normal velocity at the trailing edge of the orifice, Three different combustor-only cases were analyzed, each with a uniform inlet jet profile. None of the cases matched the plenum-fed calculations. To assess liner thickness effects, a thin-walled case was also analyzed. The CFD analysis shelved the thin-walled jets had more penetration than the thick-walled jets. C1 CFD Res Corp, Huntsville, AL 35805 USA. United Technol Res Ctr, Combust Technol Grp, E Hartford, CT 06108 USA. NASA, Lewis Res Ctr, Turbomachinery & Propuls Syst Div, Cleveland, OH 44135 USA. RP Bain, DB (reprint author), CFD Res Corp, Huntsville, AL 35805 USA. NR 21 TC 6 Z9 6 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1999 VL 15 IS 1 BP 10 EP 16 DI 10.2514/2.5411 PG 7 WC Engineering, Aerospace SC Engineering GA 159EU UT WOS:000078159500002 ER PT J AU Barber, TJ Chiappetta, LM DeBonis, JR Georgiadis, NJ Yoder, DA AF Barber, TJ Chiappetta, LM DeBonis, JR Georgiadis, NJ Yoder, DA TI Assessment of parameters influencing the prediction of shear-layer mixing SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 33rd Joint Propulsion Conference CY JUL 06-09, 1997 CL SEATTLE, WASHINGTON SP Amer Inst Aeronaut & Astronaut, ASME, SAE, ASEE ID MODEL; TURBULENCE; FLOWS AB A multisite team has completed an investigation of modeling high-speed mixing layers using the computational methods currently being applied to predict high-speed civil transport (HSCT) nozzle flowfields. The objectives of this investigation were to 1) calibrate the codes used by the various team members against the same benchmark experimental data, and 2) assess the accuracy of the Navier-Stokes codes in calculating turbulent flows having now characteristics similar to those of HSCT engine nozzles by varying user-specified input parameters, e.g., grid, turbulence model, boundary conditions. Two how geometries were investigated using the Eve codes of NASTAR, PAB3D, GIF3D, NASTD, and NPARC. The first was the heated supersonic round jet. For this configuration, with a jet-exit Mach number similar to that of the primary now from miser chutes, three nozzle flow temperatures were investigated with the five codes. Using the same grid, boundary conditions, and kappa-epsilon turbulence model (in the mixing region), very similar results were obtained for all codes, but the solutions did not agree well with the experimental velocity and temperature profiles. Further calculations using different turbulence models, compressibility corrections, and axisymmetric dissipation corrections improved the agreement with experimental data, but the corrections are not universally applicable. The second configuration was a two-dimensional supersonic mixing layer. For the flow case examined, with two supersonic streams, the five codes again produced very similar results using the same grid, boundary conditions, and turbulence model. The agreement with experimental data was better than for the round nozzle. Based on the results of this investigation, it was determined that consistent nozzle flow predictions may be obtained by the team members using the different codes investigated hereby using consistent computational grids, boundary conditions, and turbulence models. The deficiencies of these codes in predicting high-temperature compressible jets were identified and are directly related to the turbulence models currently employed. The consistency that was achieved will allow for a computational fluid dynamics procedure to be established for performing a multisite parametric design and analysis effort by the team members. C1 United Technol Res Ctr, Aeromech Chem & Fluid Syst Dept, E Hartford, CT 06108 USA. NASA, Lewis Res Ctr, Turbomachinery & Propuls Syst Div, Nozzle Branch, Cleveland, OH 44135 USA. RP Barber, TJ (reprint author), United Technol Res Ctr, Aeromech Chem & Fluid Syst Dept, E Hartford, CT 06108 USA. NR 32 TC 10 Z9 11 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1999 VL 15 IS 1 BP 45 EP 53 DI 10.2514/2.5390 PG 9 WC Engineering, Aerospace SC Engineering GA 159EU UT WOS:000078159500007 ER PT J AU Kratz, DP Rose, FG AF Kratz, DP Rose, FG TI Accounting for molecular absorption within the spectral range of the CERES window channel SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID WATER-VAPOR; RADIATIVE-TRANSFER; NONHOMOGENEOUS ATMOSPHERES; CONTINUUM ABSORPTION; REGION; CO2; PARAMETERIZATIONS; COEFFICIENTS; CFC-11; H2O AB Infrared active molecular species residing within the atmosphere cause the emerging thermal infrared spectrum of the Earth to be characterized by both line and continuum absorption (emission). Accounting for the molecular absorption within the atmosphere is critical for the proper interpretation of the satellite measured radiances. Thus, correlated k-distribution procedures have been created to account for the molecular line absorption located within the spectral range of the Clouds and the Earth's Radiant Energy System (CERES) infrared window channel (8-12 mu m); The derivation of the correlated k-distributions is based upon an exponential sum fitting of transmissions (ESFT) procedure that has been applied to monochromatic calculations at predetermined reference pressure and temperature conditions. In addition, an empirically derived, yet highly accurate parameterization of the CKD-2.1 code has been developed to calculate the atmospheric absorption attributed to the water vapor continuum located within the spectral range of the CERES infrared window channel. The multiplication transmissivity approximation has been employed to account for the overlap of the spectral features of different molecular species. The accuracy of the radiative transfer procedures incorporating the correlated k-distribution routines and the parameterized CKD-2.1 continuum routines has been established through comparisons with the reference monochromatic procedures. The correlated k-distribution yields an upwelling top of atmosphere (TOA) flux for the midlatitude summer (MLS)atmosphere that is within 0.1% of the monochromatic procedures for the CERES window channel. Neglecting the contributions from all the molecular species in the correlated k-distribution except H2O and O-3 yields an upwelling TOA flux for the MLS atmosphere with a 1.5% overestimation. Under circumstances where rapid processing is extremely critical, an error of this magnitude may be deemed acceptable; Neglecting the contributions from all of the molecular species yields an upwelling TOA flux for the MLS atmosphere with a 17.7% overestimation. An error of this magnitude is certainly not acceptable but does emphasize the need to account for the molecular absorption within the spectral range of the CERES window channel instrument. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. RP Kratz, DP (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. OI Rose, Fred G/0000-0003-0769-0772 NR 36 TC 35 Z9 35 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JAN PY 1999 VL 61 IS 1 BP 83 EP 95 DI 10.1016/S0022-4073(97)00203-3 PG 13 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 142QX UT WOS:000077212800009 ER PT J AU Bush, BC Pope, SK Bucholtz, A Valero, FPJ Strawa, A AF Bush, BC Pope, SK Bucholtz, A Valero, FPJ Strawa, A TI Surface radiation measurements during the ARESE campaign SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID SOLAR-RADIATION; ABSORPTION; CLOUDS; UNCERTAINTIES; SATELLITE; MODELS AB We describe a comprehensive set of surface radiative flux measurements made during the Fall 1995 ARM Enhanced Shortwave Experiment (ARESE) at a variety of locations in northern Oklahoma. Accurate measurements of solar spectral broadband (0.224-3.91 mu m and 0.68-3.3 mu m) and narrow spectral bandpass (10 nm) downwelling irradiances were made over atmospheric conditions ranging from "pristine" clear to heavy overcast. Precise instrument calibrations are used during analyses in deriving absolute downwelling fluxes accurate to about 1% for the broadband and 3% for the spectral instruments. Measured instrument angular responses are incorporated in these analyses to minimize deviations from ideal cosine responses. All calibrated irradiance measurements are available through the ARM ARESE archive via anonymous FTP at ftp.arm.gov and the World Wide Web at www.arm.gov. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif San Diego, Scripps Inst Oceanog, Atmospher Res Lab, La Jolla, CA 92093 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bush, BC (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Atmospher Res Lab, 9500 Gilman Dr,Dept 0242, La Jolla, CA 92093 USA. NR 23 TC 10 Z9 10 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JAN PY 1999 VL 61 IS 2 BP 237 EP 247 DI 10.1016/S0022-4073(97)00218-5 PG 11 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 142QC UT WOS:000077210800010 ER PT J AU Gnoffo, PA Weilmuenster, KJ Hamilton, HH Olynick, DR Venkatapathy, E AF Gnoffo, PA Weilmuenster, KJ Hamilton, HH Olynick, DR Venkatapathy, E TI Computational aerothermodynamic design issues for hypersonic vehicles SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Review ID ULTRAVIOLET ROCKET EXPERIMENTS; CHEMICAL-KINETIC PROBLEMS; NAVIER-STOKES EQUATIONS; FUTURE NASA MISSIONS; REACTING FLOWS; MARS ENTRIES; ALGORITHM; SCHEMES; BODIES; EARTH AB The current status of computational aerothermodynamics is discussed, with emphasis on its capabilities and limitations for contributions to the design process of hypersonic vehicles. Some topics to be highlighted include 1) aerodynamic coefficient predictions with emphasis on high-temperature gas effects; 2) surface heating and temperature predictions for thermal protection system design in a high-temperature, thermochemical nonequilibrium environment; 3) methods for extracting and extending computational fluid dynamic solutions for efficient utilization by all members of a multidisciplinary design team; 4) physical models; 5) validation process and error estimation; and 6) gridding and solution generation strategies. Recent experiences in the design of the X-33 will be featured. Computational aerothermodynamic contributions to problems in planetary entry, including the Mars Pathfinder and Stardust (Comet Sample return), will also provide a context for this discussion. Some of the barriers that currently limit computational aerothermodynamics to a predominantly reactive mode in the design process will also be discussed, with the goal of providing focus for future research. C1 NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Thermosci Inst, Hampton, VA 23681 USA. RP NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23681 USA. NR 190 TC 25 Z9 26 U1 0 U2 15 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 EI 1533-6794 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1999 VL 36 IS 1 BP 21 EP 43 DI 10.2514/2.3430 PG 23 WC Engineering, Aerospace SC Engineering GA 166LJ UT WOS:000078577800002 ER PT J AU Zeiler, TA McGhee, D Brunty, JA AF Zeiler, TA McGhee, D Brunty, JA TI Preliminary static aeroelastic analysis of reusable launch vehicle stability and control derivatives SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID HARMONIC GRADIENT-METHOD AB During the development and design of the X-33 reusable launch vehicle, loads and control analyses had been done using propulsive and aerodynamic loads derived from such sources as computational fluid dynamics and wind-tunnel models of a rigid vehicle. Required control forces and moments were determined using rigid vehicle trajectory analyses, and the detailed control load distributions were determined for achieving the required control forces and moments, again using rigid vehicle analyses. However, static aeroelastic effects on load distributions were not being considered. The objective of the work reported here was the development of models and solutions for including static aeroelasticity in the calculation of X-33 loads and in the determination of stability and control derivatives. The theory underlying the NASTRAN solutions is presented, and some of the results for the stability and control derivatives are discussed. C1 Univ Alabama, Dept Aerosp Engn & Mech, Tuscaloosa, AL 35487 USA. NASA, George C Marshall Space Flight Ctr, Struct Dynam & Loads Branch, Huntsville, AL 35812 USA. RP Zeiler, TA (reprint author), Univ Alabama, Dept Aerosp Engn & Mech, Tuscaloosa, AL 35487 USA. NR 15 TC 2 Z9 2 U1 1 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1999 VL 36 IS 1 BP 67 EP 74 DI 10.2514/2.3434 PG 8 WC Engineering, Aerospace SC Engineering GA 166LJ UT WOS:000078577800006 ER PT J AU Glass, DE Camarda, CJ Merrigan, MA Sena, JT AF Glass, DE Camarda, CJ Merrigan, MA Sena, JT TI Fabrication and testing of Mo-Re heat pipes embedded in carbon/carbon SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Two heat-pipe test articles were fabricated and tested, furthering the development of a refractory-composite/heat-pipe-cooled leading edge. A 3-ft-long, molybdenum-rhenium heat pipe with lithium working fluid was fabricated and tested in a vacuum chamber at an operating temperature of 2460 degrees F, verifying the heat-pipe design, Following the fabrication of the initial heat pipe, three additional heat pipes were fabricated and embedded in carbon/carbon. The carbon/carbon heat pipe test article was successfully tested using quartz lamps in a vacuum chamber in both horizontal and vertical orientations. Startup and steady-state data indicated similar operation in both orientations but different behavior among the three heat pipes. Radiography and eddy current evaluations were performed on the test article and indicated differing carbon/carbon thicknesses and a potential disbond. C1 Analyt Serv & Mat Inc, Hampton, VA 23666 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Glass, DE (reprint author), Analyt Serv & Mat Inc, 107 Res Dr, Hampton, VA 23666 USA. NR 18 TC 8 Z9 11 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1999 VL 36 IS 1 BP 79 EP 86 DI 10.2514/2.3436 PG 8 WC Engineering, Aerospace SC Engineering GA 166LJ UT WOS:000078577800008 ER PT J AU Bokulic, RS Moore, WV AF Bokulic, RS Moore, WV TI Near earth asteroid rendezvous (NEAR) spacecraft solar conjunction experiment SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The Near Earth Asteroid Rendezvous spacecraft was occulted by the solar disk on Feb. 19, 1997, During the period between Feb. 7 and March 3, 1997, the spacecraft X-band telecommunications system was used to carry out a combination of engineering and radio science measurements through the solar corona, The engineering results of that experiment are reported. Statistics on the uplink command acceptance rate and downlink frame error rate show that the performance of both links was reasonably good at a sun-Earth-probe (SEP) angle of about 2 deg, but degraded rapidly as the angle fell to 1 deg, Representative open-loop receiver data show moderate dips in downlink carrier amplitude (up to 4 dB) at an SEP angle of 3 deg and large dips in downlink carrier amplitude (up to 15 dB) at an SEP angle of 1 deg, Recommendations are given for future solar conjunction events, particularly in the area of ground receiver optimization, The experimental results provide a unique data set useful for the design of future planetary missions. C1 CALTECH, Jet Prop Lab, Telecommun Sci & Engn Div, Commun Syst & Res Stn, Pasadena, CA 91109 USA. RP Bokulic, RS (reprint author), Johns Hopkins Univ, Appl Phys Lab, Dept Space, Radio Frequency Commun Sect, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. NR 7 TC 6 Z9 7 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1999 VL 36 IS 1 BP 87 EP 91 DI 10.2514/2.3418 PG 5 WC Engineering, Aerospace SC Engineering GA 166LJ UT WOS:000078577800009 ER PT J AU Garrett, HB Drouilhet, SJ Oliver, JP Evans, RW AF Garrett, HB Drouilhet, SJ Oliver, JP Evans, RW TI Interplanetary meteoroid environment model update SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 36th Aerospace Sciences Meeting CY JAN 12-15, 1998 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut ID ZODIACAL LIGHT; PIONEER-10 AB The effects of the sporadic meteoroid environment on interplanetary spacecraft have an important impact on mission design, A reformulation is described of the Divine interplanetary meteoroid model, called the meteoroid engineering model (METEM), that is capable of estimating many of those effects, METEM and the original Divine model it is based on made use of the new meteoroid data obtained since the 1970s, when the original NASA meteoroid models were developed, to provide a comprehensive phase space description of the environment. METEM allows detailed estimates of the meteoroids' directionality and variation with distance from the sun, It incorporates several different meteoroid populations, each population being described in terms of a distribution function in velocity phase space, These distribution functions are integrated along a spacecraft trajectory to give the meteoroid fluence as a function of velocity and angle relative to a specified surface. METEM predictions of mission meteoroid fluences are explicitly compared with those of the standard NASA models for three representative trajectories tan inner solar system, Helios-like mission; a mission at 1 AU; and a Cassini-like, outer solar system mission). In addition, the METEM model is used to estimate the angular variations in the meteoroid fluence expected along these trajectories, a unique feature of this new class of models that provides additional insights into how a spacecraft can be designed to protect it from meteoroids. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Moorhead State Univ, Dept Math, Moorhead, MN 56560 USA. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. OAO Corp, Greenway Ctr 7500, Greenbelt, MD 20770 USA. RP Garrett, HB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 17 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1999 VL 36 IS 1 BP 124 EP 132 DI 10.2514/2.3424 PG 9 WC Engineering, Aerospace SC Engineering GA 166LJ UT WOS:000078577800015 ER PT J AU Williamsen, J Blacklock, K Evans, HJ Guay, TD AF Williamsen, J Blacklock, K Evans, HJ Guay, TD TI Quantifying and reducing international space station vulnerability following orbital debris penetration SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The increase in the orbital debris environment in low Earth orbit has prompted NASA to develop new strategies to examine the effects of penetration on spacecraft and crew. In 1992, NASA's Marshall Space Flight Center developed the Manned Spacecraft and Crew Survivability computer program to quantify the likelihood of an orbital debris particle causing loss of the International Space Station or its crew following penetration, i.e., vulnerability. The personal computer-based model computes the likelihood of occurrence for six failure modes that may lead to crew or station loss: 1) critical cracking, 2) critical equipment loss, 3) thrust-induced loss of control or joint failure, 4) fatal and nonfatal injury to crew, 5) crew hypoxia during escape and injured crew member rescue, and 6) station late loss due to critical module depressurization. The ability of the crew to perform countermeasures, i.e., shut hatches, rescue the injured, or egress the station, has been implemented into the model to assess the effectiveness of different crew protocols in reducing the overall probability of loss. By varying these parameters and selecting alternate crew operations and internal equipment designs, one can identify the optimum configurations that, if implemented, may quantifiably increase overall station and crew member survivability. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Sverdrup Technol Inc, Struct Div, Huntsville, AL 35806 USA. RP Williamsen, J (reprint author), Univ Denver, Denver Res Inst, 2050 E Iliff Ave, Denver, CO 80208 USA. NR 15 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1999 VL 36 IS 1 BP 133 EP 141 DI 10.2514/2.3425 PG 9 WC Engineering, Aerospace SC Engineering GA 166LJ UT WOS:000078577800016 ER PT J AU Wessen, RR Porter, D AF Wessen, RR Porter, D TI Market-based approach for manifesting shuttle secondary payloads SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB One of the many activities required to launch a Space Shuttle is the determination of its manifest, that Is, the selection of those payloads to be launched on a gh en mission. This task Is complicated because payload demands for Shuttle resources are requested from multiple users, the individuals generating the manifests Ire different from those requesting the resources, and a relatively large amount of time must be spent justifying why certain payloads were manifested at the expense of others. To improve this process, a market-based system was developed to explore its ability to increase the efficiency of manifesting Space Shuttle secondary payloads. These payloads, located in the Shuttle middeck lockers, are requested by many users. The proposed market-based system allocates a budget of tokens to users, who in turn use the tokens to bid for access to resources in the Shuttle middeck. The results of our experiments with this market-based process show that it can produce higher-quality manifests than a committee-driven process and requires less time to arrive at a solution. C1 Univ Arizona, Econ Sci Lab, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Miss Syst Engn Sect, Pasadena, CA 91109 USA. RP Wessen, RR (reprint author), CALTECH, Jet Prop Lab, Miss Syst Engn Sect, 4800 Oak Grove Dr,Mail Stop 301-250D, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1999 VL 36 IS 1 BP 142 EP 147 DI 10.2514/2.3426 PG 6 WC Engineering, Aerospace SC Engineering GA 166LJ UT WOS:000078577800017 ER PT J AU Morscher, GN Martinez-Fernandez, J AF Morscher, GN Martinez-Fernandez, J TI Fiber effects on minicomposite mechanical properties for several silicon carbide fiber chemically vapor-infiltrated silicon carbide matrix systems SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID REINFORCED BRITTLE-MATRIX; HYSTERESIS MEASUREMENTS; CONSTITUENT PROPERTIES; INTERFACIAL ROUGHNESS; MICROCOMPOSITE TEST; CERAMIC FIBERS; COMPOSITES; CRACKING AB Several different types of SiC fiber tows were coated with BN and composited using chemically vapor-infiltrated SiC to form single-tow minicomposites. The types of SiC fiber included Nicalon(TM), Hi-Nicalon(TM), and the new Sylramic(TM) polycrystalline SiC fiber. The interfacial shear stresses were determined from unload-reload tensile hysteresis-loop tests, The ultimate stress and strain properties also were determined for the minicomposites. The ultimate strengths of the newer Hi-Nicalon and Sylramic fibers were superior to that of Nicalon minicomposites with similar fiber volume fractions. The Sylramic minicomposites had the lowest strain to failure and highest interfacial shear strength, respectively, because of the high modulus of the fiber and the rough surface of this fiber type. The apparent interfacial shear strength increased as the stress increased for the Sylramic minicomposites, which also was attributed to the surface roughness of this fiber. C1 Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. Univ Seville, Dept Fis Mat Condensada, Seville, Spain. RP Morscher, GN (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RI MARTINEZ FERNANDEZ, JULIAN/K-1826-2012 OI MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638 NR 31 TC 24 Z9 24 U1 2 U2 12 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JAN PY 1999 VL 82 IS 1 BP 145 EP 155 PG 11 WC Materials Science, Ceramics SC Materials Science GA 158UC UT WOS:000078134500019 ER PT J AU Tai, WP Watanabe, T Jacobson, NS AF Tai, WP Watanabe, T Jacobson, NS TI High-temperature stability of alumina in argon and argon/water-vapor environments SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CORROSION AB The high-temperature stability of alumina (Al2O3) in argon and argon/water-vapor (Ar/H2O) environments has been investigated. Samples were exposed at temperatures of 1300 degrees C-1700 degrees C for 10 h, The microstructure, flexural strength, and volume all showed significant changes in the Ar/H2O environment at 1700 degrees C. Samples also became whiter, because of the oxidation of graphite impurities that had diffused from the hot-processing dies, In the Ar/H2O environment at 1700 degrees C, grain-boundary etching occurred and was much more severe than in the pure-argon environment, which was very likely caused by the enhanced formation of gaseous Al(OH)(3) and Al(OH)(2) along grain boundaries. In addition, in the Ar/H2O environment, substantial grain growth occurred in the surface vicinity. This grain growth, together with grain-boundary etching, led to a decrease in flexural strength. C1 Kyushu Natl Ind Res Inst, Dept Inorgan Composite Mat, Tosu, Saga 841, Japan. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Tai, WP (reprint author), Kyushu Natl Ind Res Inst, Dept Inorgan Composite Mat, Tosu, Saga 841, Japan. RI Jacobson, Nathan/A-9411-2009 NR 10 TC 21 Z9 22 U1 0 U2 3 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JAN PY 1999 VL 82 IS 1 BP 245 EP 248 PG 4 WC Materials Science, Ceramics SC Materials Science GA 158UC UT WOS:000078134500039 ER PT J AU Hassan, AA Thompson, T Duque, EPN Melton, J AF Hassan, AA Thompson, T Duque, EPN Melton, J TI Resolution of tail buffet phenomena for AH-64D (TM) Longbow Apache (TM) SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article; Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VIRGINIA SP Amer Helicopter Soc AB A cooperative numerical investigation involving researchers from McDonnell Douglas Helicopter Systems (MDHS), the US Army Aeroflightdynamics Directorate (AFDD) and the NASA Ames Research Center (ARC) was conducted to identify the cause, as well as the solution(s), to a pilot-reported horizontal and vertical tail buffeting problem on the Longbow Apache AH-64D helicopter in low speed descent flight, The investigation was conducted using the NASA Ames steady, three-dimensional, compressible Euler code, "TIGER." With the exception of the rotor, all geometric details of the flight test aircraft were modeled, Grid adaptation of a Cartesian computational grid near and on the surface of the configuration was used to preserve geometric integrity and solution accuracy, Flowfield diagnostics were performed using a combination of streamwise particle trajectories and cross flow vorticity plots. Numerical results indicated that two potential contributors, namely the blunt bases of the two side-mounted extended forward avionics bays (EFABS) and the bases of the two channel-like grooves created as a result of the attachment of the EFABS to the fuselage, were responsible for the shedding of high levels of vorticity which convected downstream and impacted the surfaces of the empenage, To reduce the observed levels of shed vorticity, three geometric modifications to the baseline helicopter Fuselage configuration were made. A flight test program for the helicopter with a number of suggested modifications was conducted to verify their effectiveness on resolution of the tail buffet problem. Numerical results and supporting flight test data confirming the effectiveness of the geometric modifications are presented. C1 Boeing Co, CFD, Mesa, AZ USA. NASA, Ames Res Ctr, Army Aeroflightdynam Directorate, Moffett Field, CA 94035 USA. RP Hassan, AA (reprint author), Boeing Co, CFD, Mesa, AZ USA. NR 9 TC 1 Z9 1 U1 1 U2 3 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JAN PY 1999 VL 44 IS 1 BP 16 EP 25 PG 10 WC Engineering, Aerospace SC Engineering GA 165ZU UT WOS:000078552400002 ER PT J AU Wang, PKC Hadaegh, FY AF Wang, PKC Hadaegh, FY TI Minimum-fuel formation reconfiguration of multiple free-flying spacecraft SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB The formation reconfiguration of multiple free-flying spacecraft is posed as an optimization problem involving minimum fuel expenditure. A method for obtaining simple solutions to this problem is proposed. The basic idea is to break up the formation reconfiguration process into a sequence of simple maneuvers involving a small number of spacecraft at a time. Moreover, the spacecraft move along straightline paths in the three-dimensional space. Thus, the minimum-fuel reconfiguration problem can be reduced to an optimization problem involving permutation groups. The proposed approach requires seeking fuel minimization over the set of all spacecraft permutation cycles of lengths greater than or equal to 2. Examples are given to illustrate the application of the proposed method. C1 Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, PKC (reprint author), Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. NR 17 TC 20 Z9 22 U1 0 U2 1 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JAN-JUN PY 1999 VL 47 IS 1-2 BP 77 EP 102 PG 26 WC Engineering, Aerospace SC Engineering GA 294TF UT WOS:000085925900005 ER PT J AU Sayir, A AF Sayir, A TI New developments in high temperature materials, Istanbul, Turkey, 12-15 August 1998 - Preface SO JOURNAL OF THE EUROPEAN CERAMIC SOCIETY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Sayir, A (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0955-2219 J9 J EUR CERAM SOC JI J. European Ceram. Soc. PY 1999 VL 19 IS 13-14 BP V EP VI PG 2 WC Materials Science, Ceramics SC Materials Science GA 243PE UT WOS:000083005800001 ER PT J AU Kriven, WM Palko, JW Sinogeikin, S Bass, JD Sayir, A Brunauer, G Boysen, H Frey, F Schneider, J AF Kriven, WM Palko, JW Sinogeikin, S Bass, JD Sayir, A Brunauer, G Boysen, H Frey, F Schneider, J TI High temperature single crystal properties of mullite SO JOURNAL OF THE EUROPEAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT Meeting on New Developments in High Temperature Materials CY AUG 12-15, 1998 CL ISTANBUL, TURKEY DE elastic modulus; fibers; X-ray methods; thermal expansion; mullite ID THERMAL-EXPANSION; ELASTIC PROPERTIES AB Extensive neutron diffraction and Rietveld studies of dense, hot pressed mullite (3Al(2)O(3). 2SiO(2)) have been conducted up to 1650 degrees C in air, yielding a complete set of lattice parameters and axial thermal expansion coefficients. Unconstrained powders of the same stoichiometric composition were also analyzed by X-ray diffraction and Rietveld techniques up to 900 degrees C in air, from which lattice parameters and thermal expansion coefficients were obtained. An earlier reported structural discontinuity was confirmed by XRD to lie in the temperature range 425 to 450 degrees C. Single-crystalline mullite fibers of composition 2.5Al(2)O(3). SiO2 were grown from the melt by a laser-heated, float zone method. A partial set of the single-crystal elastic moduli were determined from various sections of fiber, by Brillouin spectroscopy, from room temperature up to 1400 degrees C. They indicated a roughly 10% reduction in stiffness over that temperature range. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. Univ Illinois, Dept Geol, Urbana, IL 61801 USA. NASA, Glenn Res Ctr, Cleveland, OH USA. Univ Munich, Inst Kristallog & Angew Mineral, Munich, Germany. RP Kriven, WM (reprint author), Univ Illinois, Dept Mat Sci & Engn, 1304 W Green St, Urbana, IL 61801 USA. RI Bass, Jay/G-2599-2013 NR 34 TC 38 Z9 38 U1 1 U2 24 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0955-2219 J9 J EUR CERAM SOC JI J. European Ceram. Soc. PY 1999 VL 19 IS 13-14 BP 2529 EP 2541 DI 10.1016/S0955-2219(99)00124-7 PG 13 WC Materials Science, Ceramics SC Materials Science GA 243PE UT WOS:000083005800036 ER PT J AU Chubb, DL Pal, AT Patton, MO Jenkins, PP AF Chubb, DL Pal, AT Patton, MO Jenkins, PP TI Rare earth doped high temperature ceramic selective emitters SO JOURNAL OF THE EUROPEAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT Meeting on New Developments in High Temperature Materials CY AUG 12-15, 1998 CL ISTANBUL, TURKEY DE emitters; rare earth aluminium garnets; films; optical properties AB As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study develops a spectral emittance model for films of rare earth containing materials. Although there are several possible rave earth doped high temperature materials, this study was confined to rare earth aluminum garnets. Good agreement between experimental and theoretical spectral emittances was found for erbium, thulium and erbium-holmium aluminum garnets. Spectral emittances of these films are sensitive to temperature differences across the film. Emitter efficiency is also a sensitive function of temperature. For thulium aluminum garnet the efficiency is 0.38 at 1700 K but only 0.19 at 1262 K. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Essential Res Inc, Cleveland, OH 44122 USA. RP Chubb, DL (reprint author), NASA, Glenn Res Ctr, 21000 Brook Pk Rd, Cleveland, OH 44135 USA. NR 18 TC 48 Z9 49 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0955-2219 J9 J EUR CERAM SOC JI J. European Ceram. Soc. PY 1999 VL 19 IS 13-14 BP 2551 EP 2562 DI 10.1016/S0955-2219(99)00096-5 PG 12 WC Materials Science, Ceramics SC Materials Science GA 243PE UT WOS:000083005800038 ER PT J AU Clancey, WJ AF Clancey, WJ TI The conscious mind: In search of a fundamental theory. SO JOURNAL OF THE LEARNING SCIENCES LA English DT Book Review C1 NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. RP Clancey, WJ (reprint author), NASA, Ames Res Ctr, Computat Sci Div, M-S 269-3, Moffett Field, CA 94035 USA. NR 30 TC 0 Z9 0 U1 1 U2 3 PU LAWRENCE ERLBAUM ASSOC INC PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430-2262 USA SN 1050-8406 J9 J LEARN SCI JI J. Learn. Sci. PY 1999 VL 8 IS 3-4 BP 541 EP 556 PG 16 WC Education & Educational Research; Psychology, Educational SC Education & Educational Research; Psychology GA 239GC UT WOS:000082759600012 ER PT J AU Launius, RD AF Launius, RD TI Flying high: The story of Boeing and the rise of the jetliner industry SO JOURNAL OF THE WEST LA English DT Book Review C1 NASA, Washington, DC 20546 USA. RP Launius, RD (reprint author), NASA, Washington, DC 20546 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU J WEST INC PI MANHATTAN PA P O BOX 1009 1531 YUMA, MANHATTAN, KS 66502 USA SN 0022-5169 J9 J WEST JI J. West PD JAN PY 1999 VL 38 IS 1 BP 113 EP 113 PG 1 WC History SC History GA 168RK UT WOS:000078706200065 ER PT J AU Siegel, R AF Siegel, R TI Transient thermal analysis of parallel translucent layers by using Green's functions SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID COATINGS AB An analysis is developed for computing transient thermal behavior in a composite of two parallel translucent layers with a space between them. The radiative two-nux equation is coupled with the transient energy equation, and both equations are solved by using Green's functions. Illustrative results are provided for transient heating of two parallel translucent layers that exchange radiation. The external boundaries of the two-layer combination are each exposed to a radiative environment, and all boundaries can be convectively heated or cooled. The layer refractive indices are larger than one, and internal reflections are included with boundaries assumed diffuse. The analysis includes internal emission, absorption, isotropic scattering, and heat conduction. Transient results from the present method are verified for a single gray layer by comparison with a finite difference solution that incorporates a numerical solution of the exact radiative transfer equations for the radiative heat source. Illustrative transient temperature distributions show the effects of an insulating gap between layers, when one side of the two-layer composite is subjected to heating by radiation and convection, while the other side is being cooled. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 21 Z9 23 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN-MAR PY 1999 VL 13 IS 1 BP 10 EP 17 DI 10.2514/2.6423 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 162TP UT WOS:000078363100002 ER PT J AU Park, CS Newfield, ME Fletcher, DG Gokcen, T AF Park, CS Newfield, ME Fletcher, DG Gokcen, T TI Spectroscopic measurements of shock-layer flows in an arcjet facility SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 36th Aerospace Sciences Meeting CY JAN 12-15, 1998 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut AB Under two different test conditions, radiation emanating from the freestream and shock-layer flow over a 15.24-cm-diam blunt-body test article as measured in NASA Ames Research Center's 20 MW Aerodynamic Heating Facility Arcjet, The test gas was a mixture of air and argon. Spatially resolved emission spectra were obtained over a 2000-8900 Angstrom wavelength range using a charge-coupled device camera (1024 x 256 array) attached to a spectrograph, The optical system was calibrated using tungsten and deuterium radiation sources, Previously developed analytical tools were used to determine the following line-of-sight-averaged thermodynamic properties from the calibrated spectra: 1) rotational temperature of the freestream and 2) rotational and vibrational temperatures within the shock layer, Based on the variation in intensity of emission spectra along the stagnation streamline, shock standoff distance was determined. Two sets of data for each test condition were compared to evaluate the repeatability of measurements, Considering likely sources of errors, an uncertainty analysis was performed to estimate the error bounds of the determined properties. C1 NASA, Ames Res Ctr, Thermosci Inst, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Reacting Flow Environm Branch, Moffett Field, CA 94035 USA. RP Park, CS (reprint author), NASA, Ames Res Ctr, Thermosci Inst, Moffett Field, CA 94035 USA. NR 9 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN-MAR PY 1999 VL 13 IS 1 BP 60 EP 67 DI 10.2514/2.6401 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 162TP UT WOS:000078363100008 ER PT J AU Mirmira, SR Fletcher, LS Baker, KW AF Mirmira, SR Fletcher, LS Baker, KW TI Interfacial contact resistance of single-crystal ceramics for solar concentrators SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 36th Aerospace Sciences Meeting CY JAN 12-15, 1998 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut ID CONDUCTANCE AB An experimental investigation was conducted to determine the thermal conductivity and overall thermal resistance of stacks of single-crystal alumina and magnesia, and zirconia. From these data, the interfacial thermal resistance between the ceramic materials was evaluated over a range of pressures of 70-1720 kPa, and at two temperatures of 20 and 60 degrees C. For all three materials, the interfacial thermal resistance decreases significantly with an increase in pressure at lower pressures, beyond which it decreases more gradually. Further, the effect of temperature on the interfacial thermal resistance is negligible for the temperature range investigated. These data were used to develop an equation relating the dimensionless interfacial thermal resistance to the crystal material properties, surface characteristics, crystal thickness, apparent interface pressure, and mean interface temperature. C1 Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Mirmira, SR (reprint author), Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. NR 20 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN-MAR PY 1999 VL 13 IS 1 BP 110 EP 116 DI 10.2514/2.6407 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 162TP UT WOS:000078363100014 ER PT J AU Glass, DE Merrigan, MA Sena, JT Camarda, CJ AF Glass, DE Merrigan, MA Sena, JT Camarda, CJ TI Startup and transient performance of a Nb-1%Zr potassium heat pipe SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article C1 Analyt Serv & Mat Inc, Hampton, VA 23666 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN-MAR PY 1999 VL 13 IS 1 BP 153 EP 155 DI 10.2514/2.6414 PG 3 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 162TP UT WOS:000078363100020 ER PT J AU Hah, C Loellbach, J AF Hah, C Loellbach, J TI Development of hub corner stall and its influence on the performance of axial compressor blade rows SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article ID 3-DIMENSIONAL VISCOUS FLOWS; ROTOR AB A detailed investigation has been performed to study hub corner stall phenomena in compressor blade rows. Three-dimensional flows in a subsonic annular compressor stator and in a transonic compressor rotor have been analyzed numerically by solving the Reynolds-averaged Navier-Stokes equations. The numerical results and the existing experimental data are interrogated to understand the mechanism of compressor hub corner stall. Both the measurements and the numerical solutions for the stator indicate that a strong twisterlike vortex is formed near the rear part of the blade suction surface. Low-momentum fluid inside the hub boundary layer is transported toward the suction side of the blade by this vortex. On the blade suction surface near the hub, this vortex forces fluid to move against the main flow direction and a limiting stream surface is formed near the hub. The formation of this vortex is the main mechanism of hub corner stall. When the aerodynamic loading is increased the vortex initiates further upstream, which results in a larger corner stall region. For the transonic compressor rotor studied in this paper, the numerical solution indicates that a mild hub corner stall exists at 100 percent rotor speed The hub corner stall, however, disappears at the reduced blade loaning, which occurs at 60 percent rotor design speed The present study demonstrates that hub corner stall is caused by a three-dimensional vortex system and that it does not seem to be correlated with a simple diffusion factor for the blade row. C1 NASA, Lewis Res Ctr, ICOMP, Cleveland, OH 44135 USA. RP Hah, C (reprint author), NASA, Lewis Res Ctr, ICOMP, Cleveland, OH 44135 USA. NR 17 TC 46 Z9 52 U1 2 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JAN PY 1999 VL 121 IS 1 BP 67 EP 77 PG 11 WC Engineering, Mechanical SC Engineering GA 158UH UT WOS:000078135100008 ER PT J AU Clement, G Wood, SJ Lathan, CE Peterka, RJ Reschke, MF AF Clement, G Wood, SJ Lathan, CE Peterka, RJ Reschke, MF TI Effects of body orientation and rotation axis on pitch visual-vestibular interaction SO JOURNAL OF VESTIBULAR RESEARCH-EQUILIBRIUM & ORIENTATION LA English DT Article DE vestibulo-ocular reflex; optokinetic nystagmus; visual-vestibular interaction; otoliths ID VERTICAL OPTOKINETIC NYSTAGMUS; EYE-MOVEMENT RESPONSES; LINEAR ACCELERATION; OCULAR REFLEX; MICROGRAVITY; GRAVITY; MONKEY; SPACEFLIGHT; HUMANS; MODEL AB Spatial transformations of the vestibular-optokinetic system must account for changes in head position with respect to gravity in order to produce compensatory oculomotor responses. The purpose of this experiment was to study the influence of gravity on the vestibule-ocular reflex (VOR) in darkness and on visual-vestibular interaction in the pitch plane in human subjects using two different comparisons: (1) Earth-horizontal axis (EHA) rotation about an upright versus a supine body orientation, and (2) Earth-horizontal versus Earth-vertical (EVA) rotation axes. Visual-vestibular responses (VVR) were evaluated by measuring the slow phase velocity of nystagmus induced during sinusoidal motion of the body in the pitch plane (at 0.2 Hz and 0.8 Hz) combined with a constant-velocity vertical optokinetic stimulation (at +/- 36 degrees/s). The results showed no significant effect on the gain or phase of the VOR in darkness or on the VVR responses at 0.8 Hz between EHA upright and EHA supine body orientations. However, there was a downward shift in the VOR bias in darkness in the supine orientation. There were systematic changes in VOR and VVR between EHA and EVA for 0.2 Hz, including a reduced modulation gain, increased phase lead, and decreased bias during EVA rotation. The same trend was also observed at 0.8 Hz, but at a lesser extent, presumably due to the effects of eccentric rotation in our EVA condition and/or to the different canal input across frequencies. The change in the bias at 0.2 Hz between rotation in darkness and rotation with an optokinetic stimulus was greater than the optokinetic responses without rotation. During EHA, changes in head position relative to gravity preserve graviceptor input to the VVR regardless of body orientation. However, the modifications in VVR gain and phase when the rotation axis is aligned with gravity indicate that this graviceptive information is important for providing compensatory eye movements during visual-vestibular interaction in the pitch plane. C1 Coll France, CNRS, Lab Physiol Percept & Act, F-75231 Paris, France. Krug Life Sci, Neurosci Lab, Houston, TX USA. Catholic Univ Amer, Dept Mech Engn, Washington, DC 20064 USA. RS Dow Neurol Sci Inst, Portland, OR USA. NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. RP Clement, G (reprint author), Univ Toulouse 3, Fac Med, CNRS UMR 5549, 133 Route Narbonne, F-31062 Toulouse, France. NR 40 TC 7 Z9 7 U1 0 U2 2 PU IOS PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 0957-4271 J9 J VESTIBUL RES-EQUIL JI J. Vestib. Res.-Equilib. Orientat. PY 1999 VL 9 IS 1 BP 1 EP 11 PG 11 WC Neurosciences; Otorhinolaryngology SC Neurosciences & Neurology; Otorhinolaryngology GA 191ZN UT WOS:000080052900001 PM 10334011 ER PT J AU Hillman, EJ Bloomberg, JJ McDonald, PV Cohen, HS AF Hillman, EJ Bloomberg, JJ McDonald, PV Cohen, HS TI Dynamic visual acuity while walking in normals and labyrinthine-deficient patients SO JOURNAL OF VESTIBULAR RESEARCH-EQUILIBRIUM & ORIENTATION LA English DT Article DE oscillopsia; walking; human; dynamic visual acuity ID SPACE-FLIGHT; VESTIBULAR FUNCTION; HEAD STABILIZATION; TREADMILL WALKING; LOCOMOTOR TASKS; PERFORMANCE; HUMANS; GAZE AB We describe a new, objective, easily administered test of dynamic visual acuity (DVA) while walking. Ten normal subjects and five patients with histories of severe bilateral vestibular dysfunction participated in this study. Subjects viewed a visual display of numerals of different font sizes presented on a laptop computer while they stood still and while they walked on a motorized treadmill. Treadmill speed was adapted for 4 of 5 patients. Subjects were asked to identify the numerals as they appeared on the computer screen. Test results were reasonably repeatable in normals. The percent correct responses at each font size dropped slightly while walking in normals and dropped significantly more in patients. Patients performed significantly worse than normals while standing still and while walking. This task may be useful for evaluating post-flight astronauts and vestibularly impaired patients. C1 NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. Baylor Coll Med, Bobby R Alford Dept Otorhinolaryngol & Commun Sci, Houston, TX 77030 USA. Wyle Life Sci, Houston, TX USA. RP Bloomberg, JJ (reprint author), NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Mail Code SD3, Houston, TX 77058 USA. FU NIDCD NIH HHS [5R29DCO2412-02] NR 24 TC 47 Z9 49 U1 0 U2 1 PU IOS PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 0957-4271 J9 J VESTIBUL RES-EQUIL JI J. Vestib. Res.-Equilib. Orientat. PY 1999 VL 9 IS 1 BP 49 EP 57 PG 9 WC Neurosciences; Otorhinolaryngology SC Neurosciences & Neurology; Otorhinolaryngology GA 191ZN UT WOS:000080052900006 PM 10334016 ER PT J AU Clement, G Wood, SJ Reschke, MF Berthoz, A Igarashi, M AF Clement, G Wood, SJ Reschke, MF Berthoz, A Igarashi, M TI Yaw and pitch visual-vestibular interaction in weightlessness SO JOURNAL OF VESTIBULAR RESEARCH-EQUILIBRIUM & ORIENTATION LA English DT Article DE vestibulo-ocular reflex; optokinetic nystagmus; visual-vestibular interaction; weightlessness ID SPATIAL ORIENTATION; OPTOKINETIC NYSTAGMUS; LINEAR ACCELERATION; SPACELAB-1 MISSION; EARTHS GRAVITY; MICROGRAVITY; READAPTATION; SENSORIMOTOR; POSTURE; FLIGHT AB Both yaw and pitch visual-vestibular interactions at two separate frequencies of chair rotation (0.2 and 0.8 Hz) in combination with a single velocity of optokinetic stimulus (36 degrees/s) were used to investigate the effects of sustained weightlessness on neural strategies adopted by astronaut subjects to cope with the stimulus rearrangement of spaceflight. Pitch and yaw oscillation in darkness at 0.2 and 0.8 Hz without optokinetic stimulation, and constant velocity linear optokinetic stimulation at 18, 36, and 54 degrees/s presented relative to the head with the subject stationary, were used as controls for the visual-vestibular interactions. The results following 8 days of space flight showed no significant changes in: (1) either the horizontal and vertical vestibule-ocular reflex (VOR) gain, phase, or bias; (2) the yaw visual-vestibular response (VVR); or (3) the horizontal or vertical optokinetic (OKN) slow phase velocity (SPV). However, significant changes were observed: (1) when during pitch VVR at 0.2 Hz late inflight, the contribution of the optokinetic input to the combined oculomotor response was smaller than during the stationary OKN SPV measurements, followed by an increased contribution during the immediate postflight testing; and (2) when during pitch VVR at 0.8 Hz, the component of the combined oculomotor response due to the underlying vertical VOR was more efficiently suppressed early inflight and less suppressed immediately postflight compared with preflight observations. The larger OKN response during pitch VVR at 0.2 Hz and the better suppression of VOR during pitch VVR at 0.8 Hz postflight are presumably due to the increased role of vision early inflight and immediately after spaceflight, as previously observed in various studies. These results suggest that the subjects adopted a neural strategy to structure their spatial orientation in weightlessness by reweighting visual, otolith, and perhaps tactile/somatic signals. C1 Coll France, CNRS, Lab Physiol Percept & Act, Paris, France. Krug Life Sci, Neurosci Lab, Houston, TX USA. NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX USA. Nihon Univ, Univ Res Ctr, Tokyo, Japan. RP Clement, G (reprint author), Univ Toulouse 3, Fac Med, CNRS UMR 5549, 133 Route Narbonne, F-31062 Toulouse, France. NR 29 TC 9 Z9 9 U1 0 U2 1 PU IOS PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 0957-4271 J9 J VESTIBUL RES-EQUIL JI J. Vestib. Res.-Equilib. Orientat. PY 1999 VL 9 IS 3 BP 207 EP 220 PG 14 WC Neurosciences; Otorhinolaryngology SC Neurosciences & Neurology; Otorhinolaryngology GA 221BM UT WOS:000081695700009 PM 10436474 ER PT J AU Black, FO Paloski, WH Reschke, MF Igarashi, M Guedry, F Anderson, DJ AF Black, FO Paloski, WH Reschke, MF Igarashi, M Guedry, F Anderson, DJ TI Disruption of postural readaptation by inertial stimuli following space flight SO JOURNAL OF VESTIBULAR RESEARCH-EQUILIBRIUM & ORIENTATION LA English DT Article DE orbital space flight; postural instability; space adaptation syndrome; otolith control of posture; countermeasures ID SHUTTLE FLIGHTS; LEG MUSCLES; RESPONSES; REFLEX; ADAPTATION; SUPPORT; STANCE AB Postural instability (relative to pre-flight) has been observed in all shuttle astronauts studied upon return from orbital missions. Postural stability was more closely examined in four shuttle astronaut subjects before and after an 8 day orbital mission. Results of the pre- and post- flight postural stability studies were compared with a larger (n = 34) study of astronauts returning from shuttle missions of similar duration. Results from both studies indicated that inadequate vestibular feedback was the must significant sensory deficit contributing to the postural instability observed post flight. For two of the four IML-1 astronauts, post-flight postural instability and rate of recovery toward their earth-normal performance matched the performance of the larger sample. However, post-flight postural control in one returning astronaut was substantially below mean performance. This individual, who was within normal limits with respect to postural control before the mission, indicated that recovery to pre-flight postural stability was also interrupted by a post-flight pitch plane rotation test. A similar, though less extreme departure from the mean recovery trajectory was present in another astronaut following the same post-flight rotation test. The pitch plane rotation stimuli included otolith stimuli in the form of both transient tangential and constant centripetal linear acceleration components. We inferred from these findings that adaptation on orbit and re-adaptation on earth involved a change in sensorimotor integration of vestibular signals most likely from the otolith organs. C1 Legacy Holladay Pk Med Ctr, Clin Res & Technol Ctr, Legacy Hlth Syst, Portland, OR 97208 USA. NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. Nihon Univ, Tokyo, Japan. USN Aerosp Med Res Lab, Pensacola, FL USA. Univ Michigan, Ann Arbor, MI 48109 USA. RP Black, FO (reprint author), Legacy Holladay Pk Med Ctr, Clin Res & Technol Ctr, Legacy Hlth Syst, POB 3950, Portland, OR 97208 USA. FU NIDCD NIH HHS [2 RO1 DC 00205] NR 25 TC 19 Z9 21 U1 0 U2 0 PU IOS PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 0957-4271 J9 J VESTIBUL RES-EQUIL JI J. Vestib. Res.-Equilib. Orientat. PY 1999 VL 9 IS 5 BP 369 EP 378 PG 10 WC Neurosciences; Otorhinolaryngology SC Neurosciences & Neurology; Otorhinolaryngology GA 246FM UT WOS:000083153800006 PM 10544375 ER PT B AU Plescia, JB AF Plescia, JB BE Dressler, BO Sharpton, VL TI Gravity signature of the Teague Ring impact structure, Western Australia SO LARGE METEORITE IMPACTS AND PLANETARY EVOLUTION II SE GEOLOGICAL SOCIETY OF AMERICA SPECIAL PAPERS LA English DT Proceedings Paper CT 2nd International Conference on Large Meteorite Impacts and Planetary Evolution CY SEP 01-03, 1997 CL SUDBURY, CANADA SP Barringer Crater Co, Falconbridge Ltd, Geol Survey Canada, Inco Ltd, Lunar & Planetary Inst, Ontario Minist No Dev & Mines, Ontario Geol Survey, Quebec Minist Ressources Nat AB Teague Ring is an impact structure in Western Australia (25 degrees 50' S; 120 degrees 55' E) having a diameter of about 31 km and an age of approximately 1,630 Ma. A gravity survey over the feature defines a significant negative Bouguer anomaly of about -12 mGal, This gravity anomaly is modeled as a mass of material, corresponding to the central crystalline core of the structure, having a negative density contrast, with respect to the adjacent rocks of -0.13 g cm(-3) and extending to a depth of similar to 5 km, At Teague Ring, the extensive allochthonous and autochthonous breccia deposits (typically producing low-density material) have been removed by several kilometers of erosion. Therefore, the low-density material is interpreted to be caused by the fracturing of the crystalline basement complex below such brecciated material. The magnitude of the Teague Ring gravity anomaly is consistent with those of other similar-size terrestrial impact structures. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Plescia, JB (reprint author), US Geol Survey, 2255 N Gemini Dr, Flagstaff, AZ 86001 USA. RI Plescia, Jeffrey/B-7738-2016 NR 27 TC 1 Z9 1 U1 0 U2 2 PU GEOLOGICAL SOC AMER INC PI BOULDER PA 3300 PENROSE PL, PO BOX 9140, BOULDER, CO 80301 USA BN 0-8137-2339-6 J9 GEOL S AM S PY 1999 IS 339 BP 165 EP 175 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA BP87T UT WOS:000086466500009 ER PT S AU Rampino, MR AF Rampino, MR BE Dressler, BO Sharpton, VL TI Impact crises, mass extinctions, and galactic dynamics: The case for a unified theory SO LARGE METEORITE IMPACTS AND PLANETARY EVOLUTION II SE Geological Society of America Special Papers LA English DT Proceedings Paper CT 2nd International Conference on Large Meteorite Impacts and Planetary Evolution CY SEP 01-03, 1997 CL SUDBURY, CANADA SP Barringer Crater Co, Falconbridge Ltd, Geol Survey Canada, Inco Ltd, Lunar & Planetary Inst, Ontario Minist No Dev & Mines, Ontario Geol Survey, Quebec Minist Ressources Nat ID CRATER FORMATION RATE; OORT COMET CLOUD; PERIODICITY HYPOTHESIS; STATISTICAL TEST; DARK-MATTER; RECORD; PLANE; OSCILLATION; BOUNDARY; EOCENE AB A general model in which mass extinctions of life on Earth are related to impacts of asteroids and comets whose flux is partly modulated by the dynamics of the Milky Way Galaxy is supported by several lines of astronomical and geologic evidence. The flux of Earth-crossing objects, and calculations of the environmental effects of impacts, predict that collisions with large bodies (mostly comets) greater than or equal to 5 km in diameter (greater than or equal to 10(7) Mt TNT equivalent) could be sufficient to explain the record of similar to 25 extinction pulses in the last 545 m.y. The same evidence implies that the five major mass extinctions are related to impacts of the largest bodies (greater than or equal to 10 km in diameter, greater than or equal to 10(8) Mt events). Tests of "kill curve" relationships for impact-induced extinctions suggest that a possible threshold for catastrophic global extinction pulses occurs with impacts that produce craters with diameters between similar to 100 and 150 km, Seven of the recognized extinction peaks have thus far been correlated with concurrent (in some cases, multiple) stratigraphic impact markers and/or large impact craters. Recent statistical analyses support previous findings that the record of extinction events exhibits a periodic component of similar to 30 m.y. Additionally, spectral peaks of 30 +/- 0.5 m.y, and 35 +/- 2 m.y. have been extracted from recently revised sets of well-dated large impact craters. These results could be explained by periodic or quasi-periodic showers of Oort cloud comets. The pacemaker for such comet showers may involve the Sun's vertical oscillation through the galactic disk, with a similar cycle time between crossings of the galactic plane. Further tests of the model will involve the identification and quantification of the dark matter component in the galactic disk and improved resolution of the putative periodic signature in the record of large craters and extinction events. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Rampino, MR (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NR 60 TC 1 Z9 1 U1 0 U2 1 PU GEOLOGICAL SOC AMER INC PI BOULDER PA 3300 PENROSE PL, PO BOX 9140, BOULDER, CO 80301 USA SN 0072-1077 BN 0-8137-2339-6 J9 GEOL SOC AM SPEC PAP PY 1999 IS 339 BP 241 EP 248 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA BP87T UT WOS:000086466500016 ER PT B AU Bunch, TE Becker, L Des Marais, D Tharpe, A Schultz, PH Wolbach, W Glavin, DP Brinton, KL Bada, JL AF Bunch, TE Becker, L Des Marais, D Tharpe, A Schultz, PH Wolbach, W Glavin, DP Brinton, KL Bada, JL BE Dressler, BO Sharpton, VL TI Carbonaceous matter in the rocks of the Sudbury Basin, Ontario, Canada SO LARGE METEORITE IMPACTS AND PLANETARY EVOLUTION II SE GEOLOGICAL SOCIETY OF AMERICA SPECIAL PAPERS LA English DT Proceedings Paper CT 2nd International Conference on Large Meteorite Impacts and Planetary Evolution CY SEP 01-03, 1997 CL SUDBURY, CANADA SP Barringer Crater Co, Falconbridge Ltd, Geol Survey Canada, Inco Ltd, Lunar & Planetary Inst, Ontario Minist No Dev & Mines, Ontario Geol Survey, Quebec Minist Ressources Nat ID IMPACT STRUCTURE; AMINO-ACIDS; FULLERENES; SEDIMENTS AB Petrographic, chemical, and isotopic analyses and field studies have found a probable source for the abundant carbon in the Onaping Black Member, Fragments of a pre-impact, C-rich mudstone, found throughout the breccia deposits, contain an average of similar to 15 vol% kerogen which has a delta(13)C of 30 per mil, comparable to the bulk average of carbonaceous matter in the Black Member and to "poorly graphitized carbon" (PGC) present as fine particulates in the breccias, We suggest that shock processing on impact or in the impact cloud reduced some of the kerogen to PGC, which then fell back into ongoing deposition, particularly in the lower Black Member, PGC decreases in content upward through the deposits and is replaced by unprocessed kerogen as the main contributor to the carbon inventory, Soot of classic shape but smaller size has been identified and quantified in the lower Onwatin, Future investigations may show that the soot extends downward into the upper Black Member, The Dn ratios for detected aminos acids imply that they are both terrestrial in origin and of recent geologic age (<200 k.y.), In addition to the fullerenes reported earlier, other fullerene species of C-74, C-78, C-84, and C-100 have been identified, Two sources for the fullerenes in the Sudbury impact deposits were that the fullerences synthesized during the impact event and/or in the impact cloud, or that they were present in the bolide and survived impact, Accretionary-mantled clasts (up to 5 cm in size) and accretionary lapilli (less than or equal to 1 mm) are found mostly in the lower Black Member, The presence of lapilli, in particular, implies that the impact debris cloud was still active over the impact area during crater wall slumping and resurge-driven deposition of the lower Black Member, We attribute most of the carbon inventory in the Black Member to shock processing of preexisting terrestrial carbonaceous matter, although we do not preclude input from the impacting bolide and late depositional stage biotic activity. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Bunch, TE (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RI Glavin, Daniel/D-6194-2012 OI Glavin, Daniel/0000-0001-7779-7765 NR 36 TC 4 Z9 4 U1 0 U2 1 PU GEOLOGICAL SOC AMER INC PI BOULDER PA 3300 PENROSE PL, PO BOX 9140, BOULDER, CO 80301 USA BN 0-8137-2339-6 J9 GEOL S AM S PY 1999 IS 339 BP 331 EP 343 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA BP87T UT WOS:000086466500026 ER PT B AU Akbarzadeh-T, MR Jamshidi, M AF Akbarzadeh-T, MR Jamshidi, M BE Koussoulas, NT Groumpos, PP TI Hierarchical fuzzy control of flexible link robotic systems SO LARGE SCALE SYSTEMS: THEORY AND APPLICATIONS 1998 (LSS'98), VOL 1 LA English DT Proceedings Paper CT 8th IFAC/IFORS/IMACS/IFIP Symposium on Large Scale Systems - Theory and Applications 1998 (LSS 98) CY JUL 15-17, 1998 CL RION, GREECE SP Int Federat Automat Control, Tech Comm Large Scale Syst, Tech Comm Mfg Modeling Management & Control, Tech Comm Adv Mfg Technol, Tech Comm Man Machine Syst, Int Federat Operat Res Soc, Int Assoc Math & Comp Simulat, Int Federat Informat Proc, Greek Minist Dev, Gen Secretariat Res & Dev, Tech Chamber Greece, European Commiss, DG III, Univ Patras, Res Comm, Greek Minist Culture, Greek Minist Educ DE fuzzy control; flexible arms; large scale systems; hierarchical control; distributed parameter systems AB Experimental results are presented for hierarchical fuzzy control of a single link flexible robotic system. Furthermore, the various modules of the experimental test-bed are discussed. In particular, the computing facilities are capable of fast update of the control action which is a necessary part of control of flexible robots with fast operation. The control architecture consists of two levels. The higher level is a fuzzy classifier which determines various spatial features of the arm, the lower level is a fuzzy controller which determines the control action based on the results from the higher level fuzzy classifier and other temporal sensory information such as robot's angular positions. Copyright (C) 1998 IFAC. C1 Univ New Mexico, NASA, Ctr Autonomous Control Engn, Albuquerque, NM 87131 USA. RP Akbarzadeh-T, MR (reprint author), Univ New Mexico, NASA, Ctr Autonomous Control Engn, Albuquerque, NM 87131 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND BN 0-08-043034-1 PY 1999 BP 105 EP 110 PG 4 WC Automation & Control Systems; Engineering, Multidisciplinary SC Automation & Control Systems; Engineering GA BN82U UT WOS:000083105500016 ER PT B AU Hadaegh, FY Lu, WM Wang, PKC AF Hadaegh, FY Lu, WM Wang, PKC BE Koussoulas, NT Groumpos, PP TI Adaptive control of formation flying spacecraft for interferometry SO LARGE SCALE SYSTEMS: THEORY AND APPLICATIONS 1998 (LSS'98), VOL 1 LA English DT Proceedings Paper CT 8th IFAC/IFORS/IMACS/IFIP Symposium on Large Scale Systems - Theory and Applications 1998 (LSS 98) CY JUL 15-17, 1998 CL RION, GREECE SP Int Federat Automat Control, Tech Comm Large Scale Syst, Tech Comm Mfg Modeling Management & Control, Tech Comm Adv Mfg Technol, Tech Comm Man Machine Syst, Int Federat Operat Res Soc, Int Assoc Math & Comp Simulat, Int Federat Informat Proc, Greek Minist Dev, Gen Secretariat Res & Dev, Tech Chamber Greece, European Commiss, DG III, Univ Patras, Res Comm, Greek Minist Culture, Greek Minist Educ DE formation flying; separated spacecraft; interferometry adaptive control ID SYSTEMS AB This paper presents an adaptive control system for coordination and control of a fleet of micro-spacecraft moving in formation. A fleet of spacecraft are given as a collection of systems which interact with each other in a cooperative manner to achieve a common objective. To provide a desired formation, basic mathematical models for controlled movement of rigid bodies in free space is presented followed by the adaptive control law for formation manipulations and formation keeping. The formation control performance in the presence of constant but unknown disturbances is illustrated by simulations. Copyright (C) 1998 IFAC. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hadaegh, FY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND BN 0-08-043034-1 PY 1999 BP 117 EP 122 PG 4 WC Automation & Control Systems; Engineering, Multidisciplinary SC Automation & Control Systems; Engineering GA BN82U UT WOS:000083105500018 ER PT J AU Cowan, TE Perry, MD Key, MH Ditmire, TR Hatchett, SP Henry, EA Moody, JD Moran, MJ Pennington, DM Phillips, TW Sangster, TC Sefcik, JA Singh, MS Snavely, RA Stoyer, MA Wilks, SC Young, PE Takahashi, Y Dong, B Fountain, W Parnell, T Johnson, J Hunt, AW Kuhl, T AF Cowan, TE Perry, MD Key, MH Ditmire, TR Hatchett, SP Henry, EA Moody, JD Moran, MJ Pennington, DM Phillips, TW Sangster, TC Sefcik, JA Singh, MS Snavely, RA Stoyer, MA Wilks, SC Young, PE Takahashi, Y Dong, B Fountain, W Parnell, T Johnson, J Hunt, AW Kuhl, T TI High energy electrons, nuclear phenomena and heating in petawatt laser-solid experiments SO LASER AND PARTICLE BEAMS LA English DT Article; Proceedings Paper CT 25th European Conference on Laser Interaction with Matter (ECLIM 1998) CY MAY 07, 1998 CL FORMIA, ITALY AB The Petawatt laser at Lawrence Livermore National Laboratory (LLNL) has opened a new regime of laser matter interactions in which the quiver motion of plasma electrons is fully relativistic with energies extending well above the threshold for nuclear processes. In addition to similar to few MeV ponderomotive electrons produced in ultra intense laser-solid interactions, we have found a high energy component of electrons extending to similar to 100 MeV apparently from relativistic selffocusing and plasma acceleration in the underdense preformed plasma. The generation of hard bremsstrahlung, photonuclear reactions, and preliminary evidence for positron-electron pair production will be discussed. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Alabama, Huntsville, AL 35899 USA. George C Marshall Space Flight Ctr, Huntsville, AL 35899 USA. Univ Space Res Assoc, Huntsville, AL 35806 USA. Harvard Univ, Cambridge, MA 02138 USA. Gesell Schwerionenforsch GmbH, D-6100 Darmstadt, Germany. RP Cowan, TE (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Kuhl, Thomas/C-2243-2012; Cowan, Thomas/A-8713-2011 OI Kuhl, Thomas/0000-0001-6306-4579; Cowan, Thomas/0000-0002-5845-000X NR 20 TC 114 Z9 117 U1 0 U2 6 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0263-0346 J9 LASER PART BEAMS JI Laser Part. Beams PY 1999 VL 17 IS 4 BP 773 EP 783 PG 11 WC Physics, Applied SC Physics GA 309EJ UT WOS:000086755100023 ER PT S AU Degnan, JJ AF Degnan, JJ BE Schreiber, U Werner, C TI Engineering progress on the fully automated, photon-counting SLR2000 satellite laser ranging station SO LASER RADAR RANGING AND ATMOSPHERIC LIDAR TECHNIQUES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Ranging and Atmospheric Lidar Techniques II CY SEP 20-21, 1999 CL FLORENCE, ITALY SP Univ Florence, Dept Earth Sci, European Opt Sci, SPIE, CNR, NASA, Italian Soc Opt & Photon, Italian Space Agcy C1 NASA, Goddard Space Flight Ctr, Geosci Technol Off, Greenbelt, MD 20771 USA. RP Degnan, JJ (reprint author), NASA, Goddard Space Flight Ctr, Geosci Technol Off, Code 920 3, Greenbelt, MD 20771 USA. NR 7 TC 9 Z9 9 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 0-8194-3460-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3865 BP 76 EP 82 DI 10.1117/12.373041 PG 7 WC Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Geology; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BP39R UT WOS:000084986500009 ER PT S AU Hoge, FE AF Hoge, FE BE Kamerman, GW Werner, C TI Recent advances in laser remote sensing SO LASER RADAR TECHNOLOGY AND APPLICATIONS IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Technology and Applications IV CY JUN 16, 1999 CL MUNICH, GERMANY SP Soc Photo Opt Instrumentat Engineers, European Opt Soc, Commiss European Communities, Directorate Gen Sci Res & Dev, Wissenschaftl Gesell Lasertech e V DE laser; lidar; remote sensing; airborne; satellite; oceanic; inherent optical properties; Raman ID INHERENT OPTICAL-PROPERTIES; DISSOLVED ORGANIC-MATTER; PASSIVE CORRELATION SPECTROSCOPY; INDUCED FLUORESCENCE EMISSIONS; CHLOROPHYLL-A FLUORESCENCE; MONOMOLECULAR SEA SLICKS; WATER RAMAN BACKSCATTER; OCEAN COLOR MEASUREMENT; ABSORPTION-COEFFICIENT; SATELLITE RETRIEVAL AB Current terrestrial and hydrographic laser remote sensing research and applications are briefly reviewed. New progress in airborne oceanic lidar instrumentation and applications is then highlighted. Topics include the unique role of airborne active-passive (laser-solar) correlation spectroscopy methods in oceanic radiative transfer studies. Based on a perceived need for high resolution, improved specificity, and wider range of applicability than fluorescence methods, laser-induced resonance Raman and atomic emission spectra of oceanic constituents are suggested. C1 NASA, Goddard Space Flight Ctr, Observat Sci Branch, Lab Hydrospher Proc,Wallops Flight Facil, Wallops Island, VA 23337 USA. RP Hoge, FE (reprint author), NASA, Goddard Space Flight Ctr, Observat Sci Branch, Lab Hydrospher Proc,Wallops Flight Facil, Wallops Island, VA 23337 USA. NR 58 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 0-8194-3181-8 J9 P SOC PHOTO-OPT INS PY 1999 VL 3707 BP 2 EP 9 DI 10.1117/12.351331 PG 8 WC Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BN20D UT WOS:000081059300001 ER PT S AU Atlas, R AF Atlas, R BE Kamerman, GW Werner, C TI Application of lidar winds to data assimilation and numerical weather prediction SO LASER RADAR TECHNOLOGY AND APPLICATIONS IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Technology and Applications IV CY JUN 16, 1999 CL MUNICH, GERMANY SP Soc Photo Opt Instrumentat Engineers, European Opt Soc, Commiss European Communities, Directorate Gen Sci Res & Dev, Wissenschaftl Gesell Lasertech e V DE lidar; wind; weather; remote sensing ID IMPACT AB One of the major applications of space-based doppler wind lidar is to improve atmospheric analyses and numerical weather prediction (NWP). Since the mid 1980's, Observing System Simulation Experiments (OSSE's) have been conducted in order to evaluate the potential impact of lidar winds on NWP. These experiments have shown tremendous potential for satellite lidar observations to improve atmospheric analyses and forecasts. In addition, the OSSE's are providing an evaluation of trade-offs in lidar design, and are currently being used to define the specific requirements for lidar winds in terms of horizontal and vertical coverage and accuracy. 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 4 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 0-8194-3181-8 J9 P SOC PHOTO-OPT INS PY 1999 VL 3707 BP 268 EP 277 DI 10.1117/12.351349 PG 10 WC Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BN20D UT WOS:000081059300026 ER PT S AU Howard, RT Bryan, TC Book, ML AF Howard, RT Bryan, TC Book, ML BE Kamerman, GW Werner, C TI On-orbit testing of the Video Guidance Sensor SO LASER RADAR TECHNOLOGY AND APPLICATIONS IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Technology and Applications IV CY JUN 16, 1999 CL MUNICH, GERMANY SP Soc Photo Opt Instrumentat Engineers, European Opt Soc, Commiss European Communities, Directorate Gen Sci Res & Dev, Wissenschaftl Gesell Lasertech e V DE video; guidance; sensor; automatic rendezvous; docking; alignment AB The Video Guidance Sensor (VGS), part of NASA's Automated Rendezvous and Capture program, was flown on Shuttle mission STS-95 in October of 1998 to test on-orbit the functional characteristics of the VGS. This was the second flight of the VGS (the first flight was in 1997 on STS-87), and this time long-range tracking data was gathered during the experiment. The flight experiment sensor was designed to operate from 1.5 meter range out to 110 meter range, with a field-of-view of 16 by 21 degrees. The VGS tracked its target at a 5 Hz rate and returned 6-degree-of-freedom information on the target's position and attitude relative to the sensor. The VGS was mounted in the Shuttle cargo bay, and its target was mounted on the Spartan spacecraft being carried on this mission. The orbital testing of the VGS included operations with the target on the Shuttle's Remote Manipulator System (RMS) at the start of the 10-day mission, long-range data during the Shuttle rendezvous with the Spartan two days later, and some more RMS operations later in the mission. The data returned from the orbital testing included VGS diagnostics, acquisition, and tracking data, RMS positions, hand-held laser range data, tapes of the data from the VGS video camera, and orbital positioning data from the Spartan and the Shuttle to allow correlation of the VGS data with orbital best-estimate-of-truth data. The Video Guidance Sensor performed well in all phases of the testing, and the VGS is being incorporated into the ground testing of a complete automated rendezvous and docking system. Work on the development of the next generation VGS is continuing. C1 NASA, George C Marshall Space Flight Ctr, Orbital Syst & Robot Team, Huntsville, AL 35812 USA. RP Howard, RT (reprint author), NASA, George C Marshall Space Flight Ctr, Orbital Syst & Robot Team, Huntsville, AL 35812 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 0-8194-3181-8 J9 P SOC PHOTO-OPT INS PY 1999 VL 3707 BP 290 EP 300 DI 10.1117/12.351352 PG 11 WC Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BN20D UT WOS:000081059300028 ER PT S AU Ilchenko, VS Yao, XS Maleki, L AF Ilchenko, VS Yao, XS Maleki, L BE Kudryashov, AV TI High-Q microsphere cavity for laser stabilization and optoelectronic microwave oscillator SO LASER RESONATORS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Resonators II CY JAN 27-29, 1999 CL SAN JOSE, CA SP SPIE DE microspheres; fiber optics; microwave photonics ID WHISPERING-GALLERY MODES; FUSED-SILICA MICROSPHERES; RESONANCES; EXCITATION; MICRORESONATORS; MICROCAVITY; SCATTERING; RESONATOR; FIBER AB With submillimeter size and optical Q up to similar to 10(10), microspheres with whispering-gallery (WG) modes are attractive new component for fiber-optics/photonics applications and a potential core in ultra-compact high-spectral-purity optical and microwave oscillators. In addition to earlier demonstrated optical locking of diode laser to WG mode in a microsphere, we report on microsphere application in the microwave optoelectronic oscillator, OEO. In OEO, a steady-state microwave modulation of optical carrier is obtained in a closed loop including electro-optical modulator, fiber-optic delay, detector and microwave amplifier. OEO demonstrates exceptionally low phase noise (-140 dBc/Hz at 10kHz from similar to 10GHz carrier) with a fiber length similar to 2km. Current technology allows to put all parts of the OEO, except the fiber, on the same chip. Microspheres, with their demonstrated Q equivalent to a kilometer fiber storage, can replace fiber delays in a truly integrated device. We have obtained microwave oscillation in microsphere-based OEO at 5 to 18 GHz, with 1310nm and 1550nm optical carrier, in two configurations: 1)with external DFB pump laser, and 2)with a ring laser including microsphere and a fiber optic amplifier. Also reported is a simple and efficient fiber coupler for microspheres facilitating their integration with existing fiber optics devices. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ilchenko, VS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 28 TC 20 Z9 20 U1 0 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 0-8194-3081-1 J9 P SOC PHOTO-OPT INS PY 1999 VL 3611 BP 190 EP 198 DI 10.1117/12.349244 PG 9 WC Optics; Physics, Applied SC Optics; Physics GA BN13W UT WOS:000080851100021 ER PT B AU Ramaty, R Lingenfelter, RE AF Ramaty, R Lingenfelter, RE BE Ramaty, R VangioniFlam, E Casse, M Olive, K TI Spallogenic light elements and cosmic-ray origin SO LIBEB, COSMIC RAYS, AND RELATED X- AND GAMMA-RAYS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on LiBeB, Cosmic Rays and Gamma-Ray CY DEC 09-11, 1998 CL INST ASTROPHYS PARIS, PARIS, FRANCE SP Inst Astrophys Paris HO INST ASTROPHYS PARIS ID 25 APRIL 1998; ORION COMPLEX; EARLY GALAXY; SUPERNOVA; LINES; ABUNDANCES; EVOLUTION; SN-1987A; ISOTOPES; GRAINS AB Using a Monte Carlo code which incorporates hitherto ignored effects, the delayed mixing into the ISM of the nucleosynthetic yields of supernovae and the relationship between these yields and the supernova ejecta kinetic energy (including events with very large ejecta energies, e.g. collapsars/hypernovae), we tested the viability of the three recent evolutionary models for the origin of the spallogenic light elements, specifically Be. We find that the CRI, in which the cosmic rays are accelerated out of an ISM which is increasingly metal poor at early times, significantly under-predicts the measured Be abundance at the lowest [Fe/H], the increase in [O/Fe] with decreasing [Fe/H] indicated by recent data notwithstanding. We also find that the CRS, in which cosmic rays with composition similar to that of the current epoch cosmic rays are accelerated out of fresh supernova ejecta and thus maintain a constant metallicity at all epochs, can account for the measured Be abundances with an acceleration efficiency that is in good agreement with the current epoch cosmic-ray data. In addition, we show that the LECR, in which a postulated low energy component also accelerated out of fresh ejecta coexists with the CRI cosmic rays, can account for the observations as well, except that the required acceleration efficiency becomes prohibitively large for some of the parameters that have been previously assumed for this as-yet undetected cosmic-ray component. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ramaty, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 45 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 1-886733-93-7 J9 ASTR SOC P PY 1999 VL 171 BP 104 EP 117 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN88S UT WOS:000083346900013 ER PT S AU Ragen, TJ AF Ragen, TJ BE Musick, JA TI Human activities affecting the population trends of the Hawaiian monk seat SO LIFE IN THE SLOW LANE: ECOLOGY AND CONSERVATION OF LONG-LIVED MARINE ANIMALS SE AMERICAN FISHERIES SOCIETY SYMPOSIUM LA English DT Proceedings Paper CT Symposium on Conservation of Long-Lived Marine Animals CY AUG 24, 1997 CL MONTEREY, CA SP Amer Fisheries Soc AB The history of the Hawaiian monk seal is one of remarkable evolutionary persistence but recent and severe decline. The species may have persisted in the Hawaiian Archipelago for the past 15 million years. Its initial contact with humans probably occurred when Polynesians first settled the Archipelago, perhaps 2,000 years ago. Shortly thereafter the monk seal was likely extirpated in the main Hawaiian Islands and reduced to its current configuration of six main reproductive colonies. The first written record of the species is from 1805, when it was discovered on Lisianski Island. Through the remainder of the 1800s, it was exploited for skins and oil and for food by shipwrecked sailors. By the turn of the century, at least two of the six reproductive colonies had been extirpated and the species was severely depleted. In this century, the Hawaiian monk seal has suffered more from habitat competition and loss than from direct exploitation. Habitat loss has occurred in the form of permanent human settlement with associated disturbance, deposition of marine debris, physical and biological alteration of its terrestrial environment, and biological alteration of its marine environment. Thus, human activities have played a major role in determining the status and trends of the species over the past two centuries. The historical record also suggests that human access to the Northwestern Hawaiian Islands is increasing, and such activities may become a greater impediment to recovery if they are not limited to those compatible with wildlife conservation. Unfortunately, we are often unable to predict the compatibility of proposed activities. In the face of such uncertainty, is further development of the Northwestern Hawaiian Islands worth the risk of extinction of the Hawaiian monk seal?. C1 Natl Marine Fisheries Serv, Juneau, AK 99802 USA. RP Ragen, TJ (reprint author), Natl Marine Fisheries Serv, 709 W 9th St,Room 461, Juneau, AK 99802 USA. NR 58 TC 8 Z9 10 U1 7 U2 18 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE, STE 110, BETHESDA, MD 20814-2199 USA SN 0892-2284 BN 1-888569-15-8 J9 AM FISH S S PY 1999 VL 23 BP 183 EP 194 PG 12 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA BN69L UT WOS:000082615800014 ER PT S AU Lamotte, L Saugier, B Smernoff, DT Andre, M AF Lamotte, L Saugier, B Smernoff, DT Andre, M BE Brechignac, F MacElroy, R TI A simplified closed artificial ecosystem - Recycling of organic matter into wheat plants SO LIFE SCIENCES: ARTIFICIAL ECOSYSTEMS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4 3 and F4 4 Symposia of COSPAR Scientific Commission F Held at 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND ID CARBON AB A simplified closed system consisting of a plant growth chamber coupled to a decomposition chamber was used to study carbon exchange dynamics. The CO2 produced via the decomposition of wheat straw was used for photosynthetic carbon uptake by wheat plants. The atmosphere of the two chambers was connected through a circuit of known flow rate. Thus, monitoring the CO2 concentrations in both compartments allowed measurement of the carbon exchange between the chambers, and estimation of the rate of respiration processes in the decomposition chamber and photosynthetic rate in the producer chamber. The objective for CELSS research was to simulate a system where a compartment producing food via photosynthesis, would be supplied by CO2 produced from respiration processes. The decomposition of biomass by the decomposer simulated both the metabolism of a crew and the result of a recycling system for inedible biomass. Concerning terrestrial ecosystems, the objective was to study organic matter decomposition in soil and other processes related to permanent grasslands. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Univ Paris 11, CNRS, Ecol Vegetale Lab, F-91405 Orsay, France. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CEA, Dept Ecophysiol Vegetale & Microbiol, F-13108 St Paul Durance, France. RP Lamotte, L (reprint author), Univ Paris 11, CNRS, Ecol Vegetale Lab, F-91405 Orsay, France. NR 24 TC 2 Z9 2 U1 0 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 3 BP 303 EP 308 DI 10.1016/S0273-1177(99)00483-4 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Ecology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA BP22T UT WOS:000084442300006 PM 11542538 ER PT S AU Mancinelli, RL Smernoff, DT White, MR AF Mancinelli, RL Smernoff, DT White, MR BE Brechignac, F MacElroy, R TI Controlling denitrification in closed artificial ecosystems SO LIFE SCIENCES: ARTIFICIAL ECOSYSTEMS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4 3 and F4 4 Symposia of COSPAR Scientific Commission F Held at 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND AB Denitrification, the dissimilatory reduction of NO3- to N2O and N-2, is found in a wide variety of organisms. In closed artificial systems, especially closed plant growth chambers, a significant loss of fixed-N occurs through denitrification, thereby decreasing the efficiency of the system and fouling the atmosphere with N2O. Denitrification is a form of anaerobic respiration. Whenever available, however, denitrifiers preferentially use O-2 as their terminal electron acceptor. As a result, rates of denitrification and growth are a function of O-2 Typically,, in closed systems O-2 consumption is greater than the diffusion of O-2 through the medium to the cell, decreasing the O-2 level near the cell and denitrification occurs. Using Pseudomonas fluorescens (ATCC # 17400) as a model organism grown in a two L bioreactor under varying levels of O-2 we studied its effects on population growth and its ability to mitigate denitrification in closed systems. The results indicate that denitrification occurs in a closed system even when it is considered aerobic, that is well mixed and sparged with either air, or sufficient pure O-2 to cause a complete turnover in the gaseous atmosphere in the bioreactor vessel every five minutes. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mancinelli, RL (reprint author), NASA, Ames Res Ctr, MS 239-12, Moffett Field, CA 94035 USA. RI Mancinelli, Rocco/L-8971-2016 NR 10 TC 1 Z9 1 U1 1 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 3 BP 329 EP 334 DI 10.1016/S0273-1177(99)00319-1 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Ecology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA BP22T UT WOS:000084442300009 PM 11542541 ER PT S AU Yang, TC George, KA Wu, H Miller, D Miller, J AF Yang, TC George, KA Wu, H Miller, D Miller, J BE Yang, TC TI Cytogenetic effects of energetic ions with shielding SO LIFE SCIENCES: BIODOSIMETRY, CHROMOSOME DAMAGE AND CARCINOGENESIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F2 4 Symposium of COSPAR Scientific Commission F, at the 32nd COSPAR Scientific Assembly on Life Sciences - Biodosimetry, Chromosome Damage and Carcinogenesis CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP COSPAR Scientif Commiss F, NASA, European Space Agcy, Natl Space Dev Agcy Japan, Russian Space Agcy AB In order to understand the effects of shielding on the induction of biological damages by charged particles, we conducted experiments with accelerated protons (250 MeV) and iron particles (I GeV/u). Human lymphocytes in vitro were exposed to particle beams through polyethylene with various thickness, and chromosomal aberrations were determined using FISH technique. Dose response curves for chromosome aberrations were obtained and compared for various particle types. Experimental results indicated that for a given absorbed dose at the cell, the effectiveness of protons and iron particles in the induction of chromosomal aberrations was not significantly altered by polyethylene with thickness up to 30-cm and 15-cm respectively. Comparing with gamma rays, charged particles were very effective in producing complex chromosomal damages, which may be an important mechanism in alterating functions in nondividing tissues, such as nervous systems. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Lyndon B Johnson Space Ctr, Radiat Biophys Lab, Houston, TX 77058 USA. Wyle Labs, Houston, TX 77058 USA. Kelsey Seybold Clin, Houston, TX 77058 USA. Loma Linda Univ, Med Ctr, Loma Linda, CA 92350 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Yang, TC (reprint author), NASA, Lyndon B Johnson Space Ctr, Radiat Biophys Lab, Houston, TX 77058 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043640-4 J9 ADV SPACE RES PY 1999 VL 22 IS 12 BP 1683 EP 1690 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Biology; Genetics & Heredity; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Genetics & Heredity; Geology; Meteorology & Atmospheric Sciences GA BM91D UT WOS:000080096200006 ER PT S AU Yamada, S Yang, TC George, K Okayasu, R Ando, K Tsujii, H AF Yamada, S Yang, TC George, K Okayasu, R Ando, K Tsujii, H BE Yang, TC TI Microsatellite instability in human mammary epithelial cells transformed by heavy ions SO LIFE SCIENCES: BIODOSIMETRY, CHROMOSOME DAMAGE AND CARCINOGENESIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F2 4 Symposium of COSPAR Scientific Commission F, at the 32nd COSPAR Scientific Assembly on Life Sciences - Biodosimetry, Chromosome Damage and Carcinogenesis CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP COSPAR Scientif Commiss F, NASA, European Space Agcy, Natl Space Dev Agcy Japan, Russian Space Agcy ID GENOMIC INSTABILITY; MISMATCH REPAIR; BREAST; CANCER; GENE; CHROMOSOME; P53; CARCINOMAS; PROTEIN; LINES AB We analyzed DNA and proteins obtained from normal and transformed human mammary epithelial cells for studying the neoplastic transformation by high-LET irradiation in vitro. We also examined microsatellite instability in human mammary cells transformed to various stages of carcinogenesis, such as normal, growth variant and tumorigenic, using microsatellite marker D5S177 on the chromosome 5 and CY17 on the Chromosome 10. Microsatellite instabilities were detected in the tumorigenic stage. These results suggest that microsatellite instability may play a role in the progression of tumorigenecity. The cause of the genomic instability has been suggested as abnormalities of DNA-repair systems which may be due to one of the three reasons: 1) alterations of cell cycle regulating genes. 2) mutations in any of the DNA mismatch repair genes, 3) mutation in any of the DNA strand breaks repair genes. No abnormality of these genes and encoded proteins, however was found in the present studies. These studies thus suggest that the microsatellite instability is induced by an alternative mechanism. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Natl Inst Radiol Sci, Res Ctr Charged Particle Therapy, Chiba 2638555, Japan. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Texas, Med Branch, Galveston, TX 77555 USA. RP Yamada, S (reprint author), Natl Inst Radiol Sci, Res Ctr Charged Particle Therapy, Chiba 2638555, Japan. RI Okayasu, Ryuichi/F-2071-2013 OI Okayasu, Ryuichi/0000-0001-5091-7210 NR 17 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043640-4 J9 ADV SPACE RES PY 1999 VL 22 IS 12 BP 1709 EP 1717 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Biology; Genetics & Heredity; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Genetics & Heredity; Geology; Meteorology & Atmospheric Sciences GA BM91D UT WOS:000080096200009 ER PT S AU Soffen, GA AF Soffen, GA BE Raulin, F Kobayashi, K Brack, A TI Astrobiology SO LIFE SCIENCES: EXOBIOLOGY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 3/F3 5 Symposia of COSPAR Scientific Commission F on Life Science - Exobiology at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Univ Paris 12, Yokohama natl Univ, Int Soc Studing Origin Life, natl Aeronautical Space Adm, European Space Agcy, Ctr natl Etudes Spatiakes, Natl Space Dev Agcy Japan, Comm space Res AB If we believe life to be a cosmic imperative, the understanding of life processes becomes a universal aspect of cosmology. How does life fit into our understanding of the universe. As a compliment to NASA's 'Origins' Program we are developing a new venture to embark on one of the great scientific questions of our time, our origins, evolution and our destiny. NASA already deals with a number of related biological questions. We are introducing a new unifying approach to biology within the NASA... Astrobiology. Astrobiology is the study of the chemistry, physics and adaptations that influence the origin, evolution and destiny of life. We intent to raise the conscious level relating relevant biological questions to the formation and development of the universe through space missions and research programs. By linking certain aspects of exobiology, ecology, gravitational biology, and adding efforts in molecular biology, evolutionary biology, and planetary biology and joining this to Astronomy and planetology, we seek a deeper understanding of where the living process fits in to our cosmological theories. We do this through laboratory experiments, space observations, computer modeling, missions and discovery of what appear to be extreme conditions for us, but conditions in which life thrives. NASA has formed an international 'virtual' Astrobiology Institute as a nucleus to initiate this consolidating idea. NASA's technology will play a major role in this endeavor. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA HQ, Washington, DC USA. RP Soffen, GA (reprint author), NASA HQ, Code S, Washington, DC USA. NR 0 TC 4 Z9 4 U1 0 U2 4 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 2 BP 283 EP 288 DI 10.1016/S0273-1177(99)00048-4 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BN11U UT WOS:000080760700002 ER PT S AU Brack, A Clancy, P Fitton, B Hofmann, B Horneck, G Kurat, G Maxwell, J Ori, G Pillinger, C Raulin, F Thomas, N Westall, F AF Brack, A Clancy, P Fitton, B Hofmann, B Horneck, G Kurat, G Maxwell, J Ori, G Pillinger, C Raulin, F Thomas, N Westall, F BE Raulin, F Kobayashi, K Brack, A TI An integrated exobiology package for the search for life on Mars SO LIFE SCIENCES: EXOBIOLOGY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 3/F3 5 Symposia of COSPAR Scientific Commission F on Life Science - Exobiology at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Univ Paris 12, Yokohama natl Univ, Int Soc Studing Origin Life, natl Aeronautical Space Adm, European Space Agcy, Ctr natl Etudes Spatiakes, Natl Space Dev Agcy Japan, Comm space Res AB A multi-user integrated suite of instruments designed to optimize the search for evidence of life on Mars is described. The package includes: * Surface inspection and surface environment analysis to identify the potential Mars landing sites, to inspect the surface geology and mineralogy, to search for visible surficial microbial macrofossils, to study the surface radiation budget and surface oxidation processes, to search for niches for extant life. * Analysis of surface and subsurface minerals and organics to characterize the surface mineralogy, to analyse the surface and subsurface oxidants, to analyze the mineralogy of subsurface aliquots, to analyze the organics present in the subsurface aliquots (elemental and molecular composition, isotopes, chirality). * Macroscopic and microscopic inspection of subsurface aliquots to search for life's indicators (paleontological, biological, mineralogical) and to characterize the mineralogy of the subsurface aliquots. The study is led by ESA Manned Spaceflight and Microgravity Directorate. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 CNRS, Ctr Biophys Mol, Orleans, France. ESA, ESTEC, Noordwijk, Netherlands. ESC, Noordwijk, Netherlands. Nat Hist Museum, Bern, Switzerland. DLR, Inst Aerosp Med, Porz Wahn, Germany. Nat Hist Museum, Vienna, Austria. Univ Bristol, Dept Chem, Bristol, Avon, England. Univ Annunzio, Dipartimento Sci, Pescara, Italy. Open Univ, Planetary Sci Res Inst, Milton Keynes, Bucks, England. CNRS, LISA, Creteil, France. Univ Paris 12, Creteil, France. Univ Paris 07, Creteil, France. Max Planck Inst Aeron, Lindau, Germany. NASA, Lyndon B Johnson Space Ctr, Planetary Sci Branch, Houston, TX 77058 USA. RP Brack, A (reprint author), CNRS, Ctr Biophys Mol, 1A Ave Rech Sci, Orleans, France. OI ORI, Gian Gabriele/0000-0002-6460-1476 NR 2 TC 13 Z9 13 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 2 BP 301 EP 308 DI 10.1016/S0273-1177(99)00051-4 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BN11U UT WOS:000080760700005 ER PT S AU Israel, G Cabane, M Coll, P Coscia, D Raulin, F Niemann, H AF Israel, G Cabane, M Coll, P Coscia, D Raulin, F Niemann, H BE Raulin, F Kobayashi, K Brack, A TI The Cassini-Huygens ACP experiment and exobiological implications SO LIFE SCIENCES: EXOBIOLOGY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 3/F3 5 Symposia of COSPAR Scientific Commission F on Life Science - Exobiology at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Univ Paris 12, Yokohama natl Univ, Int Soc Studing Origin Life, natl Aeronautical Space Adm, European Space Agcy, Ctr natl Etudes Spatiakes, Natl Space Dev Agcy Japan, Comm space Res ID TITANS ATMOSPHERE; AEROSOLS; SIMULATIONS; GROWTH AB Since the discovery of its dense nitrogen atmosphere Titan, the largest satellite of Saturn has always been the subject of a strong interest by the scientific community of the exobiologists. The main reason is that Titan's atmosphere is believed to be over geologic time a permanent source of N- containing organic molecules (mostly nitriles) and of various hydrocarbons. Some of these species polymerize to form very complex organic chains which condense into aerosols. The result of this microphysical and photochemical activity is that substantial organic sediments may have accumulated on Titan's surface. The objectives of the Aerosol Collector Pyrolyser (ACP) instrument of the Huygens Probe are (1) to determine the chemical composition of the photochemical aerosols and (2) to measure the relative abundances of condensed organic gases forming the shells of the falling particles. The method consists in sampling the particles during the descent of the Probe. The method used for chemical analysis is Pyro-GC-MS technique in which the collected matter is heated in an oven and the produced pyrolysates are injected in a special inlet of the GCMS instrument (H. Nieman) of the Probe. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 CNRS, Serv Aeron, F-91371 Verrieres Buisson, France. CNRS, LISA, F-94010 Creteil, France. Univ Paris 12, F-94010 Creteil, France. Univ Paris 07, F-94010 Creteil, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Israel, G (reprint author), CNRS, Serv Aeron, BP 3, F-91371 Verrieres Buisson, France. NR 26 TC 10 Z9 10 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 2 BP 319 EP 331 DI 10.1016/S0273-1177(99)00053-8 PG 13 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BN11U UT WOS:000080760700007 ER PT S AU Mahaffy, PR A'Hearn, MF Atreya, SK Bar-Nun, A Bruston, P Cabane, M Carignan, GR Coll, P Crifo, JF Ehrenfreund, P Harpold, D Gorevan, S Israel, G Kasprzak, W Mumma, MJ Niemann, HB Owen, T Raulin, F Riedler, W Schutte, W Sternberg, R Strazzulla, G AF Mahaffy, PR A'Hearn, MF Atreya, SK Bar-Nun, A Bruston, P Cabane, M Carignan, GR Coll, P Crifo, JF Ehrenfreund, P Harpold, D Gorevan, S Israel, G Kasprzak, W Mumma, MJ Niemann, HB Owen, T Raulin, F Riedler, W Schutte, W Sternberg, R Strazzulla, G BE Raulin, F Kobayashi, K Brack, A TI The Champollion cometary molecular analysis experiment SO LIFE SCIENCES: EXOBIOLOGY SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F3 3/F3 5 Symposia of COSPAR Scientific Commission F on Life Science - Exobiology at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Univ Paris 12, Yokohama Natl Univ, Int Soc Studying Origin Life, Natl Aeronautical Space Adm, European Space Agcy, Ctr Natl Etudes Spatiakes, Natl Space Dev Agcy Japan, Comm Space Res ID PROBE MASS-SPECTROMETER; CARBON SUBOXIDE; SWS OBSERVATIONS; B2 HYAKUTAKE; HALLEY; WATER; ORIGIN; GAS; ATMOSPHERES; DISCOVERY AB The Chemical Analysis of Released Gas Experiment (CHARGE), is one of several investigations selected for the Champollion New Millennium DS4 Mission. CHARGE is presently being designed to carry out a detailed molecular and isotopic analysis of material collected from the surface and several centimeters below the surface of comet Tempel I. The highest priority scientific issues addressed by this investigation include: the chemical conditions present in the region of cometary formation; the chemical changes during cometary formation and over the lifetime of the comet; the relationship of comets to other primitive and more evolved bodies in the solar system and to the parent interstellar cloud; the contribution of cometary material to the atmospheres and oceans of planets; and the nature of the mixture of ices and dust grains which give rise to the coma and extended sources of gas as a comet approaches perihelion. CHARGE will be designed to thermally process samples of solid phase material from near the ambient temperature to approximately 900 K. Gases evolved from the frozen ices will be continuously analyzed as a function of sample temperature by a quadrupole mass spectrometer with a mass range of 2 to 300 amu. A broad range of major and trace species, both organic and inorganic, from the gases evolved from the solid samples will undergo both chemical and cold trapping for subsequent analysis by gas chromatograph mass spectrometer (GCMS) analysis. CHARGE technology heritage includes the Galileo Probe Mass Spectrometer (Niemann et al., 1996) that successfully measured the composition of Jupiter's atmosphere in December of 1995. The landed portion of the mission will enable analysis of subsurface materials and allow identification of organic species present at sub-parts per million mole-fraction in the nucleus. Prior to the landed operations, CHARGE will carry out measurements from orbit for a period of several weeks. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Tel Aviv Univ, IL-69978 Tel Aviv, Israel. Univ Paris 07, LISA, F-94010 Creteil, France. Univ Paris 12, F-94010 Creteil, France. CNRS, F-94010 Creteil, France. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. Leiden Univ, Leiden, Netherlands. Honeybee Robot, New York, NY USA. Univ Hawaii, Honolulu, HI 96822 USA. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. Citta Univ Catania, I-95125 Catania, Italy. RP Mahaffy, PR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Mahaffy, Paul/E-4609-2012; mumma, michael/I-2764-2013; Harpold, Dan/I-3345-2013 NR 43 TC 3 Z9 3 U1 1 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 1999 VL 23 IS 2 BP 349 EP 359 DI 10.1016/S0273-1177(99)00056-3 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BN11U UT WOS:000080760700010 ER PT S AU Akiyama, H Shiraishi, A Haruyama, J Terazono, J Yano, H AF Akiyama, H Shiraishi, A Haruyama, J Terazono, J Yano, H BE Raulin, F Kobayashi, K Brack, A TI Mission to Europa's sub-surface ocean and search for possible biological traces SO LIFE SCIENCES: EXOBIOLOGY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 3/F3 5 Symposia of COSPAR Scientific Commission F on Life Science - Exobiology at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Univ Paris 12, Yokohama natl Univ, Int Soc Studing Origin Life, natl Aeronautical Space Adm, European Space Agcy, Ctr natl Etudes Spatiakes, Natl Space Dev Agcy Japan, Comm space Res AB Recent close encounters to Europa, a giant Jovian satellite, by the Galileo spacecraft reenforced the hypothesis that there might exist a liquid ocean of H2O in Europa. It can be assumed that Europa, like the Earth, has biological systems under its sub surface ocean, and that marine organisms consume chemical nutrients released by geological activities even though there is no sunlight. The purpose of this paper is to introduce conceptual and feasibility studies of a spacecraft mission to explore Europa's hypothetical sub-surface ocean. In this paper, we present possible searches for the possible biological evidence through the observation of traces. We analyze the scientific rationale, the methodology and the instrumentation of our investigation held in this mission. The designs of spacecraft and mission profile is' also reviewed. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Nishimatsu Construct Co Ltd, Kanagawa 2428520, Japan. Univ Tokyo, Bunkyo Ku, Tokyo 1138654, Japan. Natl Space Dev Agcy Japan, Ibaragi 3050047, Japan. Japan Space Forum, Minato Ku, Tokyo 1050013, Japan. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Akiyama, H (reprint author), Nishimatsu Construct Co Ltd, 2570-4 Shimotsuruma, Kanagawa 2428520, Japan. NR 8 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 2 BP 367 EP 370 DI 10.1016/S0273-1177(99)00059-9 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BN11U UT WOS:000080760700012 ER PT S AU Kern, VD Sack, FD White, NJ Anderson, K Wells, W Martin, C AF Kern, VD Sack, FD White, NJ Anderson, K Wells, W Martin, C BE Hasenstein, KH Sato, A Cogoli, A Takahashi, K TI Spaceflight hardware allowing unilateral irradiation and chemical fixation in petri dishes SO LIFE SCIENCES: MICROGRAVITY RESEARCH II SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F1 4, F1 5 and F1 6 Symposia of COSPAR Scientific Commission E Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res, European Space Agcy, Natl Space Dev Agcy Japan, NASA, Ctr Natl Etud Spatiales, Inst Med Aerospatiale, Serv Sante Armee, Ctr Etude & Rech Med Aerospatiale, Amer Inst Aeronaut & Astronaut, Inst Space & Astronaut Sci, Daimler Benz Aerosp AG AB To accommodate a spaceflight experiment with moss (SPM), experiment-unique equipment (EUE) was developed by engineers at Kennedy Space Center. The hardware allows sterile culture for an extended period of time in commercial petri dishes, lateral illumination of each culture with light of a specific wavelength (660 nm; other wavelengths are possible) and a range of intensities (0.05-5 mu Mol photons m(-2)s(-1)), incubation in complete darkness, and chemical fixation to terminate the experiment under conditions of microgravity. The use of a fixative required triple containment to protect the astronaut crew. An external panel on the experiment container allowed the timing of illumination and fixation to be controlled by the crew. Light quality is provided by light emitting diodes (LEDs) that are located in the lid of the outer container, the BRIC (Biological Research In Canisters)-LED. Each canister accommodates 6 Petri Dish Fixation Units (PDFUs), and each PDFU holds one 6 cm petri dish. All components are autoclavable. LED illumination is piped through a transparent glass rod. Each PDFU contains fixative in a reservoir that is released by the depression of an actuator. This hardware performed well during its first flight, the 16-day STS-87 mission in Nov./Dec., 1997 as part of the Collaborative USA and Ukrainian Experiment (CUE). It supported vigorous and sterile moss growth, cells were maintained in position and were well-fixed, and there was a vigorous and consistent response to light. Although here used for moss, in future flight experiments this unique new hardware can be used for many types of organisms normally grown in petri dishes, with or without a requirement for illumination. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Ohio State Univ, Dept Plant Biol, Columbus, OH 43210 USA. Bionet Corp, Kennedy Space Ctr, FL USA. NASA, Kennedy Space Ctr, FL USA. RP Kern, VD (reprint author), Ohio State Univ, Dept Plant Biol, 1735 Neil Ave, Columbus, OH 43210 USA. NR 0 TC 11 Z9 11 U1 2 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 6 BP 775 EP 778 DI 10.1016/S0273-1177(99)00412-3 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology; Meteorology & Atmospheric Sciences GA BP17T UT WOS:000084336700014 PM 11542622 ER PT S AU Yoffe, B Darlington, GJ Soriano, HE Krishnan, B Risin, D Pellis, NR Khaoustov, VI AF Yoffe, B Darlington, GJ Soriano, HE Krishnan, B Risin, D Pellis, NR Khaoustov, VI BE Hasenstein, KH Sato, A Cogoli, A Takahashi, K TI Cultures of human liver cells in simulated microgravity environment SO LIFE SCIENCES: MICROGRAVITY RESEARCH II SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F1 4, F1 5 and F1 6 Symposia of COSPAR Scientific Commission E Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res, European Space Agcy, Natl Space Dev Agcy Japan, NASA, Ctr Natl Etud Spatiales, Inst Med Aerospatiale, Serv Sante Armee, Ctr Etude & Rech Med Aerospatiale, Amer Inst Aeronaut & Astronaut, Inst Space & Astronaut Sci, Daimler Benz Aerosp AG ID PRIMARY HUMAN HEPATOCYTES; DIFFERENTIATION; ANGIOGENESIS; EXPRESSION; GROWTH AB We used microgravity-simulated bioreactors that create the unique environment of low shear force and high-mass transfer to establish long-term cultures of primary human liver cells (HLC). To assess the feasibility of establishing HLC cultures, human liver cells obtained either from cells dissociated by collagenase perfusion or minced tissues were cultured in rotating vessels. Formation of multidimensional tissue-like spheroids (up to 1.0 cm) comprised of hepatocytes and. biliary epithelial cells that arranged as bile duct-like structures along newly formed vascular sprouts were observed. Electron microscopy revealed clusters of round hepatocytes and bile canaliculi with multiple microvilli and tight junctions. Scanning EM revealed rounded hepatocytes that were organized in tight clusters surrounded by a complex mesh of extracellular matrix. Also, we observed that co-culture of hepatocytes with endothelial cells stimulate albumin mRNA expression. In summary, a simulated microgravity environment is conducive for the establishment of long-term HLC cultures and allows the dissection of the mechanism of liver regeneration and cell-to-cell interactions that resembles in vivo conditions, (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Baylor Coll Med, Vet Adm Med Ctr, Houston, TX 77030 USA. Wyle Labs, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Yoffe, B (reprint author), Baylor Coll Med, Vet Adm Med Ctr, 2002 Holcombe Blvd, Houston, TX 77030 USA. NR 22 TC 21 Z9 23 U1 0 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 6 BP 829 EP 836 DI 10.1016/S0273-1177(99)00079-4 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology; Meteorology & Atmospheric Sciences GA BP17T UT WOS:000084336700021 PM 11542629 ER PT S AU Davis, WL McKay, CP Hynes, SF AF Davis, WL McKay, CP Hynes, SF BE Ehrenfreund, P Robert, F TI Remote sensing for organics on Mars SO LIFE SCIENCES: NEW INSIGHTS INTO COMPLEX ORGANICS IN SPACE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 1 Symposium of COSPRA Scientific Commission F Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Ctr Natl Etudes Spatiales, Comm Space Res ID BLACK-SEA SEDIMENTS; FLUVIAL VALLEYS; MARTIAN SOIL; CHLOROPHYLL; LIFE; ORIGIN; WATER; SPECTROSCOPY; MORPHOLOGY; EVOLUTION AB The detection of organics on Mars remains an important scientific objective. Advances in instrumentation and laboratory techniques provide new insight into the lower level detection limit of complex organics in closely packed media. Preliminary results demonstrate that algae present in a palagonite medium do exhibit a spectral reflectance feature in the visible range for dry mass weight ratios of algae to palagonite greater than 6%-which corresponds to 30 mg algae in a 470 mg (just optically thick (< 3 mm) layer) palagonite matrix. This signature most probably represents chlorophyll a, a light harvesting pigment with an emission peak at 678 nm. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 SETI Inst, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Northwestern State Univ, Natchioches, LA 71457 USA. RP Davis, WL (reprint author), SETI Inst, Moffett Field, CA 94035 USA. NR 51 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 4 BP 489 EP 496 DI 10.1016/S0273-1177(99)00083-6 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Multidisciplinary Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Science & Technology - Other Topics GA BP10H UT WOS:000084113500010 PM 11543336 ER PT S AU Van Baalen, J Roach, S AF Van Baalen, J Roach, S BE Flener, P TI Using decision procedures to accelerate domain-specific deductive synthesis systems SO LOGIC-BASED PROGRAM SYNTHESIS AND TRANSFORMATION SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 8th International Workshop on Logic-Based Program Synthesis and Transformation (LOPSTR 98) CY JUN 15-19, 1998 CL MANCHESTER, ENGLAND SP Assoc Logic Programming, ESPRIT Network Excellence Computat Logic, Prolog Dev Ctr A S, Brondby Copenhagen AB This paper describes a class of decision procedures that we have found useful for efficient, domain-specific deductive synthesis, and a method for integrating this type of procedure into a general-purpose refutation-based theorem prover. We suggest that this is a large and interesting class of procedures and show how to integrate these procedures to accelerate a general-purpose theorem prover doing deductive synthesis. While much existing research on decision procedures has been either in isolation or in the context of interfacing procedures to non-refutation-based theorem provers, this appears to be the first reported work on decision procedures in the context of refutation-based deductive synthesis where witnesses must be found. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. EM jvb@ptolemy.arc.nasa.gov; sroach@ptolemy.arc.nasa.gov NR 17 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 3-540-65765-7 J9 LECT NOTES COMPUT SC PY 1999 VL 1559 BP 61 EP 80 PG 20 WC Computer Science, Software Engineering SC Computer Science GA BN74D UT WOS:000082776300004 ER PT B AU Ritzert, F Keller, D Vasudevan, V AF Ritzert, F Keller, D Vasudevan, V BE Fuchs, GE Dannemann, KA Deragon, TC TI Investigation of the formation of topologically close packed phase instabilities in nickel-base superalloy Rene N6 SO LONG TERM STABILITY OF HIGH TEMPERATURE MATERIALS LA English DT Proceedings Paper CT Symposium on Long Term Stability of High Temperature Materials at the 1999 TMS Annual Meeting CY FEB 28-MAR 04, 1999 CL SAN DIEGO, CA SP TMS AB Topologically close packed (TCP) phase instability in third generation Ni-base superalloys is understood to hinder component performance when used in high-temperature jet engine applications. The detrimental effects on high temperature performance from these brittle phases includes weakening of the Ni-rich matrix through the depletion of potent solid solution strengthening elements. Thirty-four compositional variations of polycrystalline Rene N6 were defined from a design-of-experiments approach and then cast, homogenized, and finally aged to promote TCP formation. Our prior work reported on the results of the multiple regression modeling of these alloys in order to predict the volume fraction of TCP. This paper will present further regression modeling results on these alloys in order to predict the occurrence of TCP in third generation Ni-base superalloy microstructures. Kinetic results are also discussed. C1 NASA, Glrnn Res Ctr, Cleveland, OH 44135 USA. RP Ritzert, F (reprint author), NASA, Glrnn Res Ctr, Cleveland, OH 44135 USA. NR 7 TC 2 Z9 2 U1 1 U2 3 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-453-4 PY 1999 BP 111 EP 121 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BP03V UT WOS:000083949800007 ER PT B AU Boyan, JA AF Boyan, JA BE Bratko, I Dzeroski, S TI Least-Squares temporal difference learning SO MACHINE LEARNING, PROCEEDINGS LA English DT Proceedings Paper CT 16th International Conference on Machine Learning (ICML 99) CY JUN 27-30, 1999 CL BLED, SLOVENIA SP HERMES SoftLab, DaimlerChrysler Res & Technol Ctr, JerovsekComp, Jozef Stefan Inst, Micro Res, MLNET-II ESPRIT IV Project 29288, Slovenian Minist Sci & Technol, TEMIDA, TSE TRADE ID REINFORCEMENT AB TD(lambda) is a popular family of algorithms for approximate policy evaluation in large MDPs. TD(lambda) works by incrementally updating the value function after each observed transition. It has two major drawbacks: it makes inefficient use of data, and it requires the user to manually tune a stepsize schedule for good performance. For the case of linear value function approximations and lambda = 0, the Least-Squares TD (LSTD) algorithm of Bradtke and Barto (Bradtke and Barto, 1996) eliminates all stepsize parameters and improves data efficiency. This paper extends Bradtke and Barto's work in three significant ways. First, it presents a simpler derivation of the LSTD algorithm. Second, it generalizes from lambda = 0 to arbitrary values of lambda; at the extreme of lambda = 1, the resulting algorithm is shown to be a practical formulation of supervised linear regression. Third, it presents a novel, intuitive interpretation of LSTD as a model-based reinforcement learning technique. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Boyan, JA (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA BN 1-55860-612-2 PY 1999 BP 49 EP 56 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BV38D UT WOS:000178755300006 ER PT J AU Zhou, X Breen, ML Duraj, SA Hepp, AF AF Zhou, X Breen, ML Duraj, SA Hepp, AF TI Synthesis and structural characterization of bis(4-methylpyridine)dichloro (dimethyldithiocarbamate) gallium(III), GaCl2(4-mepy)(2)(S2CN(CH3)(2)) SO MAIN GROUP METAL CHEMISTRY LA English DT Article ID PRECURSORS AB The synthesis and structure of the gallium dithiocarbamate, GaCl2(4-mepy)(2) (S2CN(CH3)(2)), is described. Tetramethylthiuramdisulfide, (CH3)(2)NC(S)S-S(S)CN(CH3)(2), reacts with Ga2Cl4 in 4-methylpyridine at 25 degrees C to form a new gallium(lll) dithiocarbamate. The gallium(lll) dithiocarbamate, GaCl2(4-mepy)(2)(S2CN(CH3)(2)), exists in the solid state as a distorted-octahedral molecule in which the chloride ions are cis to one another and trans to the sulfurs of the dithiocarbamatedisulfide ligand. The compound crystallizes in the P (1) over bar (No. 2) space group with a = 9.0863(11) Angstrom, b = 9.2030(13) Angstrom, c = 14.0530(20) Angstrom, alpha = 81.55 (1)degrees, beta = 73.93(1)degrees, gamma= 60.82(1)degrees, Z= 2, V (Angstrom(3)) = 985.80(20), R-F = 0.055 and R-w = 0.052. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. Tulane Univ, Dept Chem, New Orleans, LA 70118 USA. RP Duraj, SA (reprint author), NASA, Lewis Res Ctr, MS 302-1, Cleveland, OH 44135 USA. NR 14 TC 5 Z9 5 U1 0 U2 2 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-7575 J9 MAIN GROUP MET CHEM JI Main Group Met. Chem. PD JAN PY 1999 VL 22 IS 1 BP 35 EP 39 PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 168TA UT WOS:000078707700006 ER PT J AU Bower, JR Seki, MP Young, RE Bigelow, KA Hirota, J Flament, P AF Bower, JR Seki, MP Young, RE Bigelow, KA Hirota, J Flament, P TI Cephalopod paralarvae assemblages in Hawaiian Islands waters SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE Paralarvae; cephalopod; Hawaiian Islands; distribution; assemblage ID OMMASTREPHIDAE; COMMUNITY; PACIFIC; LARVAE; SEA AB The distribution and abundance of cephalopod paralarvae near the Hawaiian Islands are described. Paralarvae were collected during 5 plankton surveys in 1991 to 1993. The 404 tows at 59 stations collected 10 375 paralarvae from 21 families and 57 species. The most numerous families were the Ommastrephidae (23% of total catch), Pyroteuthididae (17%), Enoploteuthididae (16%), Onychoteuthididae (14%), and Chtenopterygidae (8%). The most numerous species were Ommastrephes bartramii (18%), Pterygioteuthis microlampas (15%), Chtenopteryx sicula (8%), and Onychoteuthis compacta (6%). Analysis of paralarval distribution patterns identified 2 paralarval assemblages: 'island associated' and 'oceanic'. The 15 'island-associated' species showed increased paralarval abundance near the islands, suggesting preferential spawning in this area. Epipelagic nearshore spawners included Onychoteuthis sp. C, Sthenoteuthis oualaniensis, and Nototodarus hawaiiensis. Mesopelagic nearshore spawners included 3 reported members of the Hawaiian Mesopelagic Boundary Community (Abralia trigonura, Liocranchia reinhardti, and Chiroteuthis picteti) and 3 probable new members (Liocranchia valdiviae, Histioteuthis hoylei and Enoploteuthis jonesi). C1 Hokkaido Univ, Fac Fisheries, Hakodate, Hokkaido 0418611, Japan. Univ Hawaii Manoa, Dept Oceanog, Honolulu, HI 96822 USA. Secretariat Pacific Community, Ocean Fisheries Programme, Noumea 98848, New Caledonia. Natl Marine Fisheries Serv, Honolulu Lab, SW Fisheries Sci Ctr, NOAA, Honolulu, HI 96822 USA. RP Bower, JR (reprint author), Hokkaido Univ, Fac Fisheries, 3-1-1 Minato Cho, Hakodate, Hokkaido 0418611, Japan. EM akaika@pop.fish.hokudai.ac.jp NR 55 TC 18 Z9 23 U1 1 U2 5 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 1999 VL 185 BP 203 EP 212 DI 10.3354/meps185203 PG 10 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 237CG UT WOS:000082636700017 ER PT J AU Freese, L Auster, PJ Heifetz, J Wing, BL AF Freese, L Auster, PJ Heifetz, J Wing, BL TI Effects of trawling on seafloor habitat and associated invertebrate taxa in the Gulf of Alaska SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE trawling impacts; occupied submersible; seafloor habitat; mobile fishing gear; invertebrate bycatch ID EPIBENTHIC SCAVENGING INVERTEBRATES; CLYDE SEA AREA; LABORATORY EXPERIMENTS; BEHAVIORAL ECOLOGY; NORTH-SEA; BAIT; IMPACT; DISTURBANCE; COMMUNITIES; ATTRACTIONS AB Short-term effects of bottom trawling on a 'hard-bottom' (pebble, cobble, and boulder) seafloor were studied on the outer continental shelf in the eastern Gulf of Alaska. Eight sites were trawled in August 1996; then, from a research submersible we videotaped each trawl path and a nearby reference transect to obtain quantitative data. Boulders were displaced, and large epifaunal invertebrates were removed or damaged by a single trawl pass. These structural components of habitat were the dominant features on the seafloor. There was a significant decrease in density, and an increase in damage, to sponges and anthozoans in trawled versus reference transects. Changes in density, or damage to most motile invertebrates were not detected. Delayed mortality, of apparently undamaged invertebrates, may have resulted in greater impact than we detected. Alternatively, over time, some invertebrates may have recovered from any damage previously suffered. A subsequent survey at these sites will address these questions. C1 Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. Univ Connecticut, Natl Undersea Res Ctr N Atlantic & Great Lakes, Groton, CT 06340 USA. RP Freese, L (reprint author), Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM linc.freese@noaa.gov NR 33 TC 111 Z9 115 U1 1 U2 24 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 1999 VL 182 BP 119 EP 126 DI 10.3354/meps182119 PG 8 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 214PK UT WOS:000081336200010 ER PT J AU Ryer, CH Olla, BL AF Ryer, CH Olla, BL TI Light-induced changes in the prey consumption and behavior of two juvenile planktivorous fish SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE visual threshold; nonvisual feeding; behavior; illumination; nocturnal ID POLLOCK THERAGRA-CHALCOGRAMMA; WALLEYE POLLOCK; LATERAL-LINE; VERTICAL-DISTRIBUTION; LEPOMIS-MACROCHIRUS; ANOPLOPOMA-FIMBRIA; LARGEMOUTH BASS; YELLOW PERCH; FOOD; PALLAS AB Walleye pollock and sablefish, as 0+ yr juveniles, are pelagic particulate feeding planktivores. We conducted a series of laboratory experiments to determine how illumination influences prey consumption in these species, utilizing live Artemia sp. as prey. Both juvenile walleye pollock and sablefish were characterized by a sigmoidal relationship between the log of illumination and the number of prey consumed, with greater prey consumption at higher illuminations. The threshold illumination below which fish were no longer able to visually forage was approximately 5 x 10(-7) mu E s(-1) m(-2) for walleye pollock and 5 x 10(-5) mu E s(-1) m(-2) for sablefish, indicating that walleye pollock are better adapted for visual feeding at depth or at night than are sablefish. This is consistent with what is known about their vertical distributions at this Life stage; walleye pollock make daily vertical migrations which keep them at lower illuminations than sablefish, which remain at or near the water surface throughout the diel cycle. Although feeding more effectively in the light, both species were capable of detecting and capturing prey in darkness. C1 NOAA, Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Alaska Fisheries Sci Ctr,Fisheries Behav Ecol Grp, Newport, OR 97365 USA. RP Ryer, CH (reprint author), NOAA, Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Alaska Fisheries Sci Ctr,Fisheries Behav Ecol Grp, Newport, OR 97365 USA. EM cliff.ryer@hmsc.orst.edu NR 55 TC 46 Z9 46 U1 1 U2 10 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 1999 VL 181 BP 41 EP 51 DI 10.3354/meps181041 PG 11 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 204PE UT WOS:000080772700004 ER PT S AU Leon, R AF Leon, R BE Goodnick, SM Kailey, WF Longshore, RE Zhang, YH TI Intermixing induced tunability in infrared emitting InGaAs/GaAs quantum dots. SO MATERIALS AND ELECTRONICS FOR HIGH-SPEED AND INFRARED DETECTORS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials and Electronics for High-Speed and Infrared Detectors CY JUL 19-23, 1999 CL DENVER, CO SP SPIE ID TIME-RESOLVED PHOTOLUMINESCENCE; PHONON BOTTLENECK; BARRIER HEIGHT; LUMINESCENCE; EMISSION; WELLS AB The effects of intermixing on the radiative emission from InGaAs/GaAs quantum dot (QD) structures with excited state luminescence are presented. Thermally induced compositional disordering of the InGaAs/GaAs interface has been used to blue-shift all peaks and tune their intersublevel energy spacings (Delta E[(i + 1) - i]). The inhomogeneously broadened photoluminescence (PL) peaks narrowed. The intersublevel spacings Delta E[(i + 1)- i] were reduced and could be tuned continuously for values of Delta E[(i+1) - i] greater, similar and lower than the LO phonon energies in InAs and GaAs. Experiments and calculations of interdiffusion in InGaAs/GaAs quantum wells of the same ternary composition determined values for activation energies and diffusivities These established values for diffusion lengths corresponding to the observed blue shifts and reduction of Delta E[(i + 1) - i] with annealing temperature. Rate equation simulations of our experimentally obtained pi, spectra were used to estimate relaxation lifetime ratios for intersublevel transitions. A slight trend towards increasing thermalization rates at values Delta E[(i+1) - i] similar to LO phonon energies was found. However, PL measurements showed strong emission from excited states for all Delta E[(i+1) - i] values, which ranged from 53 to 25 meV. 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. NR 22 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 0-8194-3280-6 J9 P SOC PHOTO-OPT INS PY 1999 VL 3794 BP 8 EP 14 DI 10.1117/12.366743 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Materials Science, Multidisciplinary; Optics SC Engineering; Instruments & Instrumentation; Materials Science; Optics GA BN98D UT WOS:000083742300002 ER PT S AU Wilson, JW Cucinotta, FA Miller, J Shinn, JL Thibeault, SA Singleterry, RC Simonsen, LC Kim, MH AF Wilson, JW Cucinotta, FA Miller, J Shinn, JL Thibeault, SA Singleterry, RC Simonsen, LC Kim, MH BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI Materials for shielding astronauts from the hazards of space radiations SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd ID GALACTIC COSMIC-RAYS; MODEL AB One major obstacle to human space exploration is the possible limitations imposed by the adverse effects of long-term exposure to the space environment. Even before human spaceflight began, the potentially brief exposure of astronauts to the very intense random solar energetic particle (SEP) events was of great concern. A new challenge appears in deep space exploration from exposure to the low-intensity heavy-ion flux of the galactic cosmic rays (GCR) since the missions an of long duration and the accumulated exposures can be high. Because cancer induction rates increase behind low to rather large thickness of aluminum shielding according to available biological data on mammalian exposures to GCR like ions, the shield requirements for a Mars mission are prohibitively expensive in terms of mission launch costs. Preliminary studies indicate that materials with high hydrogen content and low atomic number constituents are most efficient in protecting the astronauts. This occurs for two reasons: the hydrogen is efficient in breaking up the heavy GCR ions into smaller less damaging fragments and the light constituents produce few secondary radiations (especially few biologically damaging neutrons). An overview of the materials related issues and their impact on human space exploration will be given. C1 NASA, Langley Res Ctr, Hampton, VA 23682 USA. RP Wilson, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23682 USA. NR 28 TC 8 Z9 11 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 3 EP 15 PG 13 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100001 ER PT S AU Ferguson, D Siebert, M Wilt, D Kolecki, J AF Ferguson, D Siebert, M Wilt, D Kolecki, J BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI The abrasion of aluminum, platinum, and nickel by Martian dust as determined by the Mars Pathfinder Wheel Abrasion Experiment SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd AB The Mars Pathfinder Wheel Abrasion Experiment (WAE) spun a specially prepared wheel with strips of aluminum, platinum, and nickel, in the Martian soil. These materials were chosen because of their differing hardnesses, their ability to stick to anodized aluminum, and their comparative chemical inertness under Earth launch and Mars landing conditions. Abrasion of those samples was detected by the change in their specular reflectances of sunlight as measured by a photovoltaic sensor mounted above the wheel. The degree of abrasion occurring on the samples is discussed, along with comparisons to the abrasion seen in Earth-based laboratory experiments using Martian soil analogs. Conclusions are reached about the hardness, grain size, and angularity of the Martian soil particles, and the precautions which must be undertaken to avoid abrasion on moving parts exposed to the Martian dust. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ferguson, D (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 1 Z9 1 U1 1 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 17 EP 23 PG 7 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100002 ER PT S AU Hickey, GS AF Hickey, GS BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI Materials for thermal control for Mars surface operations SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd AB The thermal environment for Mars surface exploration provides unique challenges for materials for use in structure and thermal control. The Sojourner Mars Rover has a lightweight integrated structure/insulation that has been environmentally tested and qualified for the Pathfinder mission to Mars. The basic structure with insulation, called the Warm Electronics Box (WEB), accounts for only 10% of the total Rover mass. The WEB is a thermal isolating composite structure with co-cured thermal control surfaces and an ultra-lightweight hydrophobic solid silica aerogel which minimizes conduction and radiation. This design provides excellent thermal insulation at low gas pressures and meets the structural requirements for spacecraft launch loads and for a 60 g impact landing at Mars without damage to the insulation or structure. Since the Pathfinder mission, this basic design concept has been developed and improved for future Mars surface robotic missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hickey, GS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 3 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 25 EP 31 PG 7 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100003 ER PT S AU Hepp, AF Linne, DL Landis, GA AF Hepp, AF Linne, DL Landis, GA BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI Metal alloy propellants produced from lunar resources SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd ID POWER AB The ultimate success of a permanent lunar base will depend upon the use of available resources. Two important resources available on the moon are oxygen and metals. We examine issues, including lunar resources, processing, power, and engine performance, surrounding the use of lunar resources for metal/oxygen engines, including the performance of metal alloys as rocket fuels. Results of this analysis have uncovered several promising candidates including alloys of Al-Ca, Al-Mg, Al-Si, Ca-Mg, and Ca-Si. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hepp, AF (reprint author), NASA, John H Glenn Res Ctr, Lewis Field, Cleveland, OH 44135 USA. NR 19 TC 0 Z9 0 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 39 EP 47 PG 9 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100005 ER PT S AU Hoffman, RW Fatemi, NS Stan, MA Jenkins, P Weizer, VG Scheiman, DA Brinker, DJ AF Hoffman, RW Fatemi, NS Stan, MA Jenkins, P Weizer, VG Scheiman, DA Brinker, DJ BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI High efficiency monolithic multi-junction solar cells using lattice-mismatched growth SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd AB The demand for spacecraft power has dramatically increased recently. Higher efficiency, multijunction devices are being developed to satisfy the demand. The multi-junction cells presently being developed and flown do not employ optimized bandgap combinations for ultimate efficiency due to the traditional constraint of maintaining lattice match to available substrates. We are developing a new approach to optimize the bandgap combination and improve the device performance that is based on relaxing the condition of maintaining lattice match to the substrate. We have designed cells based on this approach, fabricated single junction components cells and tested their performance. We will report on our progress toward achieving beginning-of-life AMO multi-junction device conversion efficiencies above 30%. C1 NASA, Lewis Res Ctr, Essential Res Inc, Cleveland, OH 44135 USA. RP Hoffman, RW (reprint author), NASA, Lewis Res Ctr, Essential Res Inc, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 10 TC 6 Z9 6 U1 1 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 51 EP 62 PG 12 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100006 ER PT S AU Landis, GA Bailey, SG Sexton, A AF Landis, GA Bailey, SG Sexton, A BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI A testbed for testing materials properties in space SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd AB The Photovoltaic Engineering Testbed (PET) is a facility to fly on the International Space Station to test advanced solar cell types in the space environment. The purpose is to reduce the cost of validating new technologies and bringing them to spaceflight readiness by measuring them in the in-space environment. The facility is scheduled to be launched in 2002. C1 NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, Lewis Res Ctr, Ohio Aerosp Inst, Mailstop 302-1, Cleveland, OH 44135 USA. NR 2 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 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 79 EP 82 PG 4 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100009 ER PT S AU Chubb, DL Pal, AT Patton, MO Jenkins, PP AF Chubb, DL Pal, AT Patton, MO Jenkins, PP BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI Rare earth doped yttrium aluminium garnet (YAG) selective emitters SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd AB As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study presents a spectral emittance model for films and cylinders of rare earth doped yttrium aluminum garnets. Good agreement between experimental and theoretical film spectral emittances was found for erbium and holmium aluminum garnets. Spectral emittances of films are sensitive to temperature differences across the film. For operating conditions of interest, the film emitter experiences a linear temperature variation whereas the cylinder emitter has a more advantageous uniform temperature. Emitter efficiency is also a sensitive function of temperature. For holminum aluminum garnet film the efficiency is 0.35 at 1446K but only 0.27 at 1270 K. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chubb, DL (reprint author), NASA, Lewis Res Ctr, 21000 Brook Pk Rd, Cleveland, OH 44135 USA. NR 19 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 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 107 EP 121 PG 15 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100013 ER PT S AU Good, BS Bozzolo, G Noebe, RD AF Good, BS Bozzolo, G Noebe, RD BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI Monte Carlo prediction of alloy structure SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE Materials Research Society Symposium Proceedings LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd ID MECHANICAL-PROPERTIES; SEGREGATION AB As the performance demands on metal alloys of interest to the aerospace community continue to increase, the complexity of these alloys has tended to grow as well, with corresponding increases in the cost and time needed to develop future generations of materials. While the traditional empirical approach to designing these materials has proven effective, as the complexity of the materials grows, such methods will become less efficient, limiting prospects for further improvement. The incorporation of theoretically- and computationally-based input into the design process has the potential to both improve the quality of, and reduce the time to design, new materials. Among the most fundamental issues in new materials design, the prediction of the crystallographic structure of solids has long been a goal of researchers in the field of computer simulation. To become an effective tool for assisting in the process of alloy design, a computational scheme must make use of an energy method fast enough to allow consideration of a large number of candidate structures, and an efficient energy minimization scheme. In this work, we discuss our application of Monte Carlo methods, using the BFS semi-empirical energy method developed in our laboratory, to the problem of prediction of the crystallographic structure of multi-component metal alloys. Using a simple Metropolis Monte Carlo method in conjunction with an accurate and transferable method for computing energetics, we have investigated the crystallographic structure of a variety of fcc- and bcc-based intermetallic compounds, and have considered the influence of alloying additions in compounds having up to five constituents. We discuss the successes and limitations of the methodology, and the prospects for obtaining accurate prediction of physical properties from our results. We also emphasize the role of this type of methodology as part of a synergistic experimental-theoretical effort for alloy design. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Good, BS (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOC PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 137 EP 148 PG 12 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100016 ER PT S AU Klimeck, G Salazar-Lazaro, CH Stoica, A Cwik, T AF Klimeck, G Salazar-Lazaro, CH Stoica, A Cwik, T BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI "Genetically engineered" nanostructure devices SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd ID SIMULATION; TRANSPORT; DIODE AB Material variations on an atomic scale enable the quantum mechanical functionality of devices such as resonant tunneling diodes (RTDs), quantum well infrared photodetectors (QWIPs), quantum well lasers, and heterostructure field effect transistors (HFETs). The design and optimization of such heterostructure devices requires a detailed understanding of quantum mechanical electron transport. The Nanoelectronic Modeling Tool (NEMO) is a general-purpose quantum device design and analysis tool that addresses this problem. NEMO was combined with a parallelized genetic algorithm package (PGAPACK) to optimize structural and material parameters. The electron transport simulations presented here are based on a full band simulation, including effects of non-parabolic bands in the longitudinal and transverse directions relative to the electron transport and Hartree charge self-consistency. The first result of the genetic algorithm driven quantum transport calculation with convergence of a random structure population to experimental data is presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Klimeck, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Klimeck, Gerhard/A-1414-2012 OI Klimeck, Gerhard/0000-0001-7128-773X NR 9 TC 6 Z9 6 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 149 EP 154 PG 6 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100017 ER PT S AU Southward, RE Thompson, DS Thompson, DW Scott, JL Broadwater, ST AF Southward, RE Thompson, DS Thompson, DW Scott, JL Broadwater, ST BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI Highly reflective and surface conductive silver-polyimide films fabricated via reduction of silver(I) in a thermally curing poly(amic acid) matrix SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd AB Highly reflective and surface conductive silvered polyimide films have been prepared by the incorporation of the (1,1,1-trifluoro-2,4-pentanedionato)silver(I) complex into a dimethylacetamide solution of the poly(amic acid) formed from 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) and 4,4'-oxydianiline (ODA). Thermal curing of the silver(I)containing poly(amic acid) films leads to cycloimidization with concomitant silver(I) reduction yielding a reflective and conductive silvered film surface. C1 NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. RP Southward, RE (reprint author), NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. NR 13 TC 4 Z9 5 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 163 EP 168 PG 6 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100019 ER PT S AU Frazier, DO Paley, MS Penn, BG Abdeldayem, HA Smith, DD Witherow, WK Carswell, WE Zugrav, MI AF Frazier, DO Paley, MS Penn, BG Abdeldayem, HA Smith, DD Witherow, WK Carswell, WE Zugrav, MI BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI The effects of ground and space processing on the properties of organic, polymeric, and colloidal materials SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE Materials Research Society Symposium Proceedings LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd ID PHTHALOCYANINE THIN-FILMS; 3RD-ORDER OPTICAL NONLINEARITIES; ANGLE SPECTROSCOPIC ELLIPSOMETRY; COPPER PHTHALOCYANINE; LANGMUIR-BLODGETT; MICROGRAVITY ENVIRONMENT; 2ND-HARMONIC GENERATION; POLYDIACETYLENE FILMS; CRYSTAL-STRUCTURES; SINGLE-CRYSTALS AB In recent years, a great deal of interest has been directed toward the use of organic materials in the development of high-efficiency optoelectronic and photonic devices. There is a myriad of possibilities among organic materials, which allows flexibility in the design of unique structures with a variety of functional groups. The use of nonlinear optical (NLO) organic materials as thin-film waveguides allows full exploitation of their desirable qualities by permitting long interaction lengths and large susceptibilities allowing modest power input.(1) There are several methods in use to prepare thin films such as Langmuir-Blodgett (LB) and self-assembly techniques,(2-4) vapor deposition,(5-7) growth from sheared solution or melt,(8,9) and melt growth between glass plates.(10) Organic-based materials have many features that make them desirable for use in optical devices, such as high second- and third-order nonlinearity, flexibility of molecular design, and damage resistance to optical radiation. However, processing difficulties for crystals and thin films has hindered their use in devices. We discuss the potential role of microgravity processing of a few organic and polymeric materials. It is of interest to note how materials with second- and third-order NLO behavior may be improved in a diffusion-limited environment and ways in which convection may be detrimental to these materials. We focus our discussion on third-order materials for all-optical switching, and second-order materials for frequency conversion and electro-optics. The goal of minimizing optical loss obviously depends on processing methods. For solution-based processes, such as solution crystal growth and solution photopolymerization, it is well known that thermal- and solutal-density gradients can initiate buoyancy-driven convection. Resultant fluid flows can affect transport of material to and from growth interfaces and become manifest in the morphology and homogeneity of the growing film or crystal. Likewise, buoyancy-driven convection can hinder production of defect-free, high-quality crystals or films during crystal and film growth by vapor deposition. C1 NASA, Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP NASA, Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NR 78 TC 0 Z9 0 U1 0 U2 4 PU MATERIALS RESEARCH SOC PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 183 EP 201 PG 19 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100022 ER PT S AU Chen, PS Stanton, WP AF Chen, PS Stanton, WP BE Hepp, AF Prahl, JM Keith, TG Bailey, SG Fowler, JR TI Artificial aging effects on cryogenic fracture toughness of the main structural alloy for the super light weight tank SO MATERIALS IN SPACE-SCIENCE, TECHNOLOGY AND EXPLORATION SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials in Space-Science, Technology and Exploration at the 1998 MRS Fall Meeting CY NOV 29-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc, NASA, Elsevier Sci Ltd ID ALUMINUM-LITHIUM ALLOYS; TEMPERATURES; BEHAVIOR; AMBIENT AB At Marshall Space Flight Center (MSFC), a new aging technique has been developed that can significantly enhance the cryogenic fracture toughness (CFT) of Alloy 2195, as well as reducing the statistical spread of fracture toughness values. This technique improves cryogenic properties by promoting T-1 nucleation and growth in the matrix, so that T-1 nucleation and growth can be suppressed in the subgrain boundaries. It also minimizes mechanical property scatter due to unavoidable variations in thermomechanical processing parameters and alloy chemistry. C1 George C Marshall Space Flight Ctr, Res Inst, Met Res Facil, IIT, Huntsville, AL 35812 USA. RP Chen, PS (reprint author), George C Marshall Space Flight Ctr, Res Inst, Met Res Facil, IIT, Bldg 4628, Huntsville, AL 35812 USA. NR 7 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 1-55899-457-2 J9 MATER RES SOC SYMP P PY 1999 VL 551 BP 285 EP 290 PG 6 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BP33N UT WOS:000084731100033 ER PT S AU Volz, MP Szofran, FR Cobb, SD Ritter, TM AF Volz, MP Szofran, FR Cobb, SD Ritter, TM BE Ramachandran, N TI Influence of applied thermal gradients and a static magnetic field on Bridgman-grown GeSi alloys SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE Bridgman crystal growth; magnetic field; segregation; germanium; silicon ID DIRECTIONALLY SOLIDIFIED HGCDTE; GE1-XSIX MIXED-CRYSTALS; MACROSEGREGATION; CONVECTION AB The effect of applied axial and radial thermal gradients and an axial static magnetic field on the macrosegregation profiles of Bridgman-grown GeSi alloy crystals has been assessed. The axial thermal gradients were adjusted by changing the control setpoints of a seven-zone vertical Bridgman furnace. The radial thermal gradients were affected by growing samples in ampoules with different thermal conductivities, namely graphite, hot-pressed boron nitride (BN), and pyrolytic boron nitride (PBN). Axial macrosegregation profiles of these samples fell between the predictions for a completely mixed melt and one where solute transport is dominated by diffusion. All of the samples were grown on Ge seeds. This resulted in a period of free growth until the Si concentration in the sold was in equilibrium with the Si concentration in the liquid. The length of crystal grown during this period was inversely proportional to the applied axial thermal gradient. Several samples were grown in an axial 5 Tesla magnetic field. Measured macroscopic segregation profiles on these samples indicate that the magnetic field did not, in general, reduce the melt flow velocities to below the growth velocities. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Volz, MP (reprint author), NASA, George C Marshall Space Flight Ctr, SD47, Huntsville, AL 35812 USA. NR 17 TC 1 Z9 1 U1 3 U2 6 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 23 EP 30 DI 10.1117/12.351282 PG 8 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700003 ER PT S AU Ramachandran, N AF Ramachandran, N BE Ramachandran, N TI Physical vapor transport of ZnSe - Modeling studies: Current status and future course SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE physical vapor transport; numerical modeling; microgravity; Stefan flux; buoyancy ID CRYSTAL-GROWTH; MICROGRAVITY CONDITIONS; CDTE AB Bulk growth of wide band gap II-VI semiconductors by physical vapor transport (PVT) has been developed and refined over the past several years at NASA Marshall Space Flight Center. Results from a modeling study of PVT crystal growth of ZnSe are reported in this paper. The PVT process is numerically investigated using a two-dimensional formulation of the governing equations and associated boundary conditions. Both the incompressible Boussinesq approximation and a compressible model are tested to determine the influence of gravity on the process and to discern the differences between the two approaches. The influence of a residual gas is included in the models. The results show that both the incompressible and compressible approximations provide comparable results and the presence of a residual gas tends to measurably reduce the mass flux in the system. Detailed flow, thermal and concentration profiles are provided. The simulations show that the Stefan flux dominates the system flow field and the subtle gravitational effects can be gauged by subtracting this flux from the calculations. Shear flows, due to solutal buoyancy, of the order of 50 microns/s for the horizontal growth orientation and 10 microns/s for the vertical orientation are predicted. Whether these flows can fully account for the observed gravity related growth morphological effects and inhomogeneous solute and dopant distributions is a matter of conjecture. A template for future modeling efforts in this area is suggested which incorporates a mathematical approach to the tracking of the growth front based on energy of formation concepts. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Ramachandran, N (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, SD 47, Huntsville, AL 35812 USA. NR 18 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 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 73 EP 84 DI 10.1117/12.351297 PG 12 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700008 ER PT S AU Banks, CE Zhu, S Frazier, DO Penn, B Abdeldayem, H Hicks, R Sarkisov, S AF Banks, CE Zhu, S Frazier, DO Penn, B Abdeldayem, H Hicks, R Sarkisov, S BE Ramachandran, N TI Electrical field effects in phthalocyanine film growth by vapor deposition SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE organic material; electrical field; phthalocyanine; non-linear optical material; vapor growth ID THIN-FILMS AB Phthalocyanine films have been synthesized by vapor deposition on quartz substrates. Some substrates were coated with a very thin gold film for introducing electrical field. These films have been characterized by x-ray diffraction and scanning electron microscopy. The films have excellent chemical and optical stability. However, the surface of these films grown without electrical field shows whisk-like morphology. When films are deposited under an electrical field, a dense film with flat surface is obtained. A change of film structure in growth orientations and solid state phases is also observed for the film synthesized under electrical fields. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Banks, CE (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. OI banks, craig/0000-0002-0756-9764 NR 13 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 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 85 EP 92 DI 10.1117/12.351266 PG 8 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700009 ER PT S AU Kassemi, M AF Kassemi, M BE Ramachandran, N TI Steady and oscillatory thermocapillary convection generated by a bubble in 1-G and low-G applications SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE bubbles; microgravity; thermocapillary convection; natural convection; oscillatory flows AB Three recent microgravity experiments have been hampered by convection caused by unwanted voids and/or bubbles which evolved in the melt. In this paper, we study steady and oscillatory thermocapillary and natural convective flows generated by a bubble in the surrounding fluid environment using a controlled model experiment with silicone oil. The dynamic characteristics of the time-dependent convection are captured using a combined numerical-experimental approach. It is shown that only below the critical Marangoni number, steady state conditions are attainable. With increasing Ma number, there is a complete transition from steady state up to a final non-periodic fluctuating flow regime through several complicated symmetric and asymmetric oscillatory states. The most prevalent oscillatory mode corresponds to a symmetric up and down fluctuation of the temperature and flow fields associated with an axially travelling wave. Careful examination of the numerical results reveals that the origin of this class of convective instability is closely related to an intricate temporal coupling between large-scale thermal structures which develop in the fluid and the temperature sensitive surface of the bubble. Gravity and natural convection play an important role in the formation of these thermal structures and the initiation of the oscillatory convection. Consequently, in low-g, the time evolution of the temperature and flow fields around the bubble are very different from their l-g counterparts for all Ma numbers. C1 NASA, Glenn Res Ctr, Natl Microgravity Res Ctr, Cleveland, OH USA. RP Kassemi, M (reprint author), NASA, Glenn Res Ctr, Natl Microgravity Res Ctr, Cleveland, OH USA. NR 8 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 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 154 EP 168 DI 10.1117/12.351273 PG 15 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700016 ER PT S AU Robinson, MB Li, DL Rathz, TJ AF Robinson, MB Li, DL Rathz, TJ BE Ramachandran, N TI Undercooling of Cu-based binary alloys in a flux and long drop tube SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE undercooling; Cu-based alloys; drop tube; fluxing; liquid separation; dispersion; coalescence ID THERMODYNAMIC ANALYSIS; NB; SYSTEM AB Several Cu-based alloys such as Cu-Co, Cu-Fe and Cu-Nb, which are of considerable technological importance, possess a flattened liquidus implying a thermodynamic tendency to immiscibility upon undercooling. In this paper, both container and containerless processing were used to study the undercooling behavior, metastable liquid separation and microstructural development in the Cu-based systems. For undercooling experiments in an oxide flux, the melt separation temperature could be measured and the metastable liquid miscibility gap has been directly determined; while containerless processing in the 105 m drop tube permits larger undercooling to be achieved prior to solidification. All phase-separated samples were found to exhibit droplet-shaped morphologies, however there were various droplet size distributions, dependent upon composition, undercooling and cooling rate. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Robinson, MB (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NR 19 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 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 202 EP 208 DI 10.1117/12.351278 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700020 ER PT S AU Zhu, S Su, CH Lehoczky, SL George, MA AF Zhu, S Su, CH Lehoczky, SL George, MA BE Ramachandran, N TI Morphology and structure of ZnO films synthesized by off-axis sputtering deposition SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE ZnO; photonic material; off-axis sputtering; morphology; growth mechanism AB A growth mechanism is studied by investigating the morphology and structure of ZnO films under different growth conditions and orientations. ZnO films are deposited on (0001) sapphire and quartz substrates by off-axis sputtering deposition at various pressures and temperatures. All films reveal highly textured structures on glass substrates and epitaxial growth on sapphire substrates. X-ray diffraction, scanning probe microscopy, and electrical measurements are used to characterize these films. The full width at half maximum of theta rocking curves for epitaxial films is less than 0.5 degrees. In textured films, it rises to several degrees. The morphology on the surface of textured films is of a granular round shape. The epitaxial films reveal flat surface but some hexagonal facets appear when the growth temperature is increased. At a pressure of 150 mTorr, a morphology transition from large flat grains to hexagonal facets occurs at 550 degrees C. Also, the conductivity of films decreases with the increase of growth temperatures. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Zhu, S (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. NR 13 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 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 218 EP 224 DI 10.1117/12.351280 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700022 ER PT S AU Rhim, WK AF Rhim, WK BE Ramachandran, N TI Development of an electrostatic levitator and containerless processing of metals, alloys, and semiconductors SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE electrostatic levitator; thermophysical properties; undercooling and solidification; molten metals and semiconductors; density; specific heat; surface tension; viscosity; electrical resistivity; hemispherical total emissivity ID NONCONTACT MEASUREMENT TECHNIQUE; HEMISPHERICAL TOTAL EMISSIVITY; ZR41.2TI13.8CU12.5NI10.0BE22.5 ALLOY; LIQUID; DROPS; HEAT; STABILITY; PARTICLES; ZIRCONIUM; VOLUMES AB Present capability of the High Temperature Electrostatic Levitator (HTESL) at JPL for the containerless materials processing is described. The capability includes the measurements of various thermophysical properties and the studies of undercooling and nucleation phenomena The thermophyscial properties that can be measured include the density, the volume expansion, the ratio between the specific heat capacity and the hemispherical total emissivity, the surface tension, the viscosity, the spectral emissivity, and the electrical resistivity. For liquids where the Wiedemann-Franz-Lorenz law applies, their thermal conductivities can be determined indirectly from the electrical resistivities. The capability of determining the statistical nature of nucleation and the Temperature-Time-Transformation (T-T-T) curves has also been demontrated. Experimental results on pure metals, alloys, and semiconductors were use to support the argument. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rhim, WK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 183-401, Pasadena, CA 91109 USA. NR 39 TC 0 Z9 0 U1 2 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 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 252 EP 263 DI 10.1117/12.351285 PG 12 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700026 ER PT S AU Mazuruk, K AF Mazuruk, K BE Ramachandran, N TI Methods of viscosity measurements in sealed ampoules SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE AB Viscosity of semiconductor and metallic melts is usually measured by oscillating cup method. This method utilizes the melts contained in vacuum sealed silica ampoules, thus the problems related to volatility, contamination, and high temperature and pressure can be alleviated. In a typical design, the time required for a single measurement is of the order of one hour. In order to reduce this time to a minute range, a high resolution (0.05 arc.sec) angular detection system is implemented in our design of the viscometer. Furthermore, an electromagnet generating a rotational magnetic field(RMF) is incorporated into the apparatus. This magnetic field can be used to remotely and nonintrusively measure the electrical conductivity of the melt. It can also be used to induce a well controlled rotational flow in the system. The transient behavior of this flow can potentially yield the viscosity of the fluid. Based on RMF implementation, two novel viscometry methods are proposed in this work: a) the transient torque method, b) the resonance method. A unified theoretical approach to the three methods (oscillating cup, transient torque, and resonance) is presented along with the initial test results of the constructed apparatus. Advantages of each of the method are discussed. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Mazuruk, K (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 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 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 264 EP 273 DI 10.1117/12.351286 PG 10 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700027 ER PT S AU Paradis, PF Rhim, WK AF Paradis, PF Rhim, WK BE Ramachandran, N TI Thermophysical properties of zirconium measured using electrostatic levitation SO MATERIALS RESEARCH IN LOW GRAVITY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials Research in Low Gravity II CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE zirconium; thermophysical properties; high temperature; containerless laser processing; electrostatic levitation ID NONCONTACT MEASUREMENT TECHNIQUE; EMISSIVITY; NICKEL; HEAT AB Six thermophysical properties of both the solid and liquid zirconium measured using the high-temperature electrostatic levitator at IPL are presented. These properties are: density, thermal expansion coefficient, constant pressure heat capacity, hemispherical total emissivity, surface tension and viscosity. For the first time, we report the densities and the thermal expansion coefficients of both the solid as well as liquid Zr over wide ranges of temperatures. Over the 1700 similar to 2300 K temperature span, the liquid density can be expressed as rho(1)(T) = 6.24 x 10(3) - 0.29 (T - Tm) kg/m(3) with T-m = 2128 K, and the corresponding volume expansion coefficient as alpha(1) = 4.6 x 10(-5) /K. Similarly, over the 1250 similar to 2100 K range, the measured density of the solid can be expressed as rho(S)(T) = 6.34 x 10(3) - 0.15 (T - T-m), giving a volume expansion coefficient alpha(S) = 2.35 x 10(-5) /K. The constant pressure heat capacity of the liquid phase could be estimated as C-pl(T) = 39.72 - 7.42 x 10(-3) (T - T-m) J/mol/K if the hemispherical total emissivity of the liquid phase epsilon(Tl) remains constant at 0.3 over the 1825 similar to 2200 K range. Over the 1400 - 2100 K temperature span, the hemispherical total emissivity of the solid phase could be rendered as epsilon(Ts)(T) = 0.29 - 9.91 x 10(3) (T - T-m). The measured surface tension and the viscosity of the molten zirconium over the 1850 similar to 2200 K range can be expressed as sigma(T) = 1.459 x 10(3) - 0.244 (T - T-m) mN/m and as eta(T) = 4.83 - 5.31 x 10(-3)(T -T-m) mPa.s, respectively. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Paradis, PF (reprint author), CALTECH, Jet Prop Lab, M-S 183-401, Pasadena, CA 91109 USA. NR 22 TC 1 Z9 1 U1 1 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3278-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3792 BP 292 EP 300 DI 10.1117/12.351289 PG 9 WC Crystallography; Materials Science, Multidisciplinary; Optics SC Crystallography; Materials Science; Optics GA BN40Q UT WOS:000081827700030 ER PT J AU Huband, J Li, W Smith, R AF Huband, J Li, W Smith, R TI An explicit representation of Bloor-Wilson PDE surface model by using canonical basis for Hermite interpolation SO MATHEMATICAL ENGINEERING IN INDUSTRY LA English DT Article ID PARTIAL-DIFFERENTIAL EQUATIONS AB The Bloor-Wilson PDE surface model uses a solution to a fourth-order elliptic PDE, along with four boundary conditions, to generate a surface patch between two fixed boundary curves. The analytic solution to the PDE system is simple to derive, but does not provide a function explicitly in terms of the boundary conditions. When implemented, this form of the function requires several computational steps. By using a canonical basis representation for Hermite interpolation, one can determine a solution to the PDE explicitly in terms of the boundary conditions. This explicit representation will reduce the number of computational steps to generate a surface patch. C1 Georgia So Univ, Dept Math, Statesboro, GA 30460 USA. Old Dominion Univ, Norfolk, VA 23529 USA. NASA, LaRC, Hampton, VA 23681 USA. RP Huband, J (reprint author), Georgia So Univ, Dept Math, Statesboro, GA 30460 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU VSP BV PI ZEIST PA PO BOX 346, 3700 AH ZEIST, NETHERLANDS SN 0169-121X J9 MATH ENG IND JI Math. Eng. Ind. PY 1999 VL 7 IS 4 BP 421 EP 431 PG 11 WC Mathematics, Interdisciplinary Applications SC Mathematics GA 224UC UT WOS:000081916700003 ER PT B AU Wolf, DR AF Wolf, DR BE VonderLinden, W Dose, V Fischer, R Preuss, R TI A Bayesian reflection on surfaces - The multiresolution inference of continuous-basis fields SO MAXIMUM ENTROPY AND BAYESIAN METHODS SE FUNDAMENTAL THEORIES OF PHYSICS LA English DT Proceedings Paper CT 18th International Workshop on Maximum Entropy and Bayesian Methods of Statistical Analysis CY JUL 27-31, 1998 CL GARCHING, GERMANY SP Deutsch Phys Gesell, Max Planck Inst Plasmaphys DE field; inference; manifold; surface; Bayesian inference; Kalman Filter; multigrid; maximally informative inference; stochastic process; adaptive scale inference; knowledge representation; minimum description length AB The topic of this paper is a novel continuous-basis field representation and inference framework applied to the inference of continuous surfaces from measurements (for example camera image data). Traditional approaches to surface representation and inference are briefly reviewed. The new field representation and inference paradigm is then introduced within a maximally informative (MI) (see [1]) inference framework. The knowledge representation is introduced and discussed in the context of MI inference. Then, using the MI inference approach, the here-named Generalized Kalman Filter (GKF) equations are derived. The GKF equations allow the update of field knowledge from previous knowledge at any scale, and new data, to new knowledge at any other scale. The GKF equations motivate a location-dependent scale or multigrid approach to the MI inference of continuous-basis fields. Several problems are uniquely solved: The MI inference of fields, where the basis for the field is itself a continuous object and generally is not representable in a finite manner; the tradeoff between accuracy of representation in terms of information learned, and memory or storage capacity in bits the approximation of probability distributions so that a maximal amount of information about the object being inferred is preserved by the approximation. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wolf, DR (reprint author), NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5766-3 J9 FUND THEOR PY 1999 VL 105 BP 83 EP 90 PG 8 WC Physics, Mathematical SC Physics GA BP62H UT WOS:000085708600008 ER PT B AU Wolf, DR AF Wolf, DR BE VonderLinden, W Dose, V Fischer, R Preuss, R TI Posterior moments of the Cauchy distribution SO MAXIMUM ENTROPY AND BAYESIAN METHODS SE Fundamental Theories of Physics LA English DT Proceedings Paper CT 18th International Workshop on Maximum Entropy and Bayesian Methods of Statistical Analysis CY JUL 27-31, 1998 CL GARCHING, GERMANY SP Deutsch Phys Gesell, Max Planck Inst Plasmaphys DE Cauchy distribution; Bayesian estimation; moment analysis; parameter estimation; parameter inference; sufficient statistics AB The posterior moments of parameters specifying distributions are minimum mean square Bayesian estimators for the corresponding moments of those parameters, and as such are ubiquitous in the Bayesian approach to statistical inference of distributions. The Cauchy distribution is most notable for its wide tails decided absence of high-order moments, and non-existence of less-than-data dimension sufficient statistics. Thus it vastly differs qualitatively from the Gaussian distribution, where tails are small, moments of all orders exist, and dimension-two sufficient statistics always exist. In this paper the posterior moments of the position parameter of the Cauchy distribution are found in closed form. (Estimating the other parameter, the width or distance parameter of the Cauchy is done using the same mathematics.) The interplay between the amount of data acquired for the estimation of the position parameter and the existence of higher order moments of the inferred posterior distribution for the postition parameter is made explicit. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wolf, DR (reprint author), NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. EM greywolf@ptolemy.arc.nasa.gov NR 3 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5766-3 J9 FUND THEOR PHYS PY 1999 VL 105 BP 149 EP 155 PG 7 WC Physics, Mathematical SC Physics GA BP62H UT WOS:000085708600016 ER PT S AU Starnes, JH Ambur, DR AF Starnes, JH Ambur, DR BE Soares, CAM Soares, CMM Freitas, MJM TI Some composite structures experiences at NASA Langley Research Center SO MECHANICS OF COMPOSITE MATERIALS AND STRUCTURES SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES E, APPLIED SCIENCES LA English DT Proceedings Paper CT Conference of the NATO-Advanced-Study-Institute on Mechanics of Composite Materials and Structures CY JUL 12-24, 1998 CL TROIA, PORTUGAL SP NATO, Inst Adv Study, IDMEC, Inst Mech Engn, Inst Super Tecn, Tech Univ Lisbon ID IMPACT RESPONSE; LAMINATED COMPOSITE; PLATES; CFRP; SUBJECT; DAMAGE; LOADS; MASS AB The results of an analytical and experimental study of the effect of impactor mass and plate radius of curvature on the low-speed impact response of laminated composite plates is presented. Dropped-weight and airgun impact responses, damage characteristics, and residual strengths of quasi-isotropic and orthotropic plates are presented for a range of impact energy levels determined by systematically varying the mass of the impactor. The flat plate responses are compared with the responses of curved plates with three different radii of curvature. Measured contact forces and damage areas are also presented. The results indicate that contact force and damage area are nonlinear functions of the impactor mass and vary considerably over the entire range of impact energy levels considered. The different damage levels caused by impactors with a given impact-energy level and with different masses significantly influence the compressive residual strength of impact damaged plates. The trends in the results for contact force, damage area, and compression-after-impact strength are clear and consistent when the data are expressed as a function of the impactor momentum. The contact force, damage initiation, and residual strength results for curved plates suggest that the low-speed impact response of plates is also a function of the radius of curvature. C1 NASA, Langley Res Ctr, Struct Mech Branch, Hampton, VA 23681 USA. RP Starnes, JH (reprint author), NASA, Langley Res Ctr, Struct Mech Branch, Hampton, VA 23681 USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0168-132X BN 0-7923-5870-8 J9 NATO ADV SCI I E-APP PY 1999 VL 361 BP 489 EP 508 PG 20 WC Engineering, Mechanical; Mechanics; Materials Science, Composites SC Engineering; Mechanics; Materials Science GA BP45R UT WOS:000085198800033 ER PT J AU Litvin, FL Lu, J Townsend, DP Howkins, M AF Litvin, FL Lu, J Townsend, DP Howkins, M TI Computerized simulation of meshing of conventional helical involute gears and modification of geometry SO MECHANISM AND MACHINE THEORY LA English DT Article AB The authors propose approaches for computerized simulation of meshing of aligned and misaligned involute helical gear. Algorithms for TCA (tooth contact analysis) computer programs were proposed. Influence of misalignment on the shift of the bearing contact and transmission errors has been investigated. Numerical examples that illustrate the developed theory are provided. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Illinois, Dept Engn Mech, Gear Res Lab, Chicago, IL 60607 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Allison Engine Co, Indianapolis, IN 46206 USA. RP Litvin, FL (reprint author), Univ Illinois, Dept Engn Mech, Gear Res Lab, 842 W Taylor St, Chicago, IL 60607 USA. NR 6 TC 28 Z9 38 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-114X J9 MECH MACH THEORY JI Mech. Mach. Theory PD JAN PY 1999 VL 34 IS 1 BP 123 EP 147 DI 10.1016/S0094-114X(98)00013-5 PG 25 WC Engineering, Mechanical SC Engineering GA 131LW UT WOS:000076578400008 ER PT J AU Pohorille, A New, MH Schweighofer, K Wilson, MA AF Pohorille, A New, MH Schweighofer, K Wilson, MA TI Insights from computer simulations into the interaction of small molecules with lipid bilayers SO MEMBRANE PERMEABILITY SE CURRENT TOPICS IN MEMBRANES LA English DT Review ID NICOTINIC ACETYLCHOLINE-RECEPTOR; MEYER-OVERTON HYPOTHESIS; MONTE-CARLO SIMULATIONS; WATER-HEXANE INTERFACE; DYNAMICS SIMULATIONS; TRANSMEMBRANE REGION; GENERAL-ANESTHESIA; SOLUTE DIFFUSION; ION-CHANNEL; MEMBRANES C1 NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. RP Pohorille, A (reprint author), NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. NR 72 TC 11 Z9 11 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 USA SN 1063-5823 J9 CURR TOP MEMBR PY 1999 VL 48 BP 49 EP 76 PG 28 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA BN74G UT WOS:000082776900003 ER PT S AU Budraa, NK Jackson, HW Barmatz, M Pike, WT Mai, JD AF Budraa, NK Jackson, HW Barmatz, M Pike, WT Mai, JD GP IEEE IEEE TI Low pressure and low temperature hermetic wafer bonding using microwave heating SO MEMS '99: TWELFTH IEEE INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, TECHNICAL DIGEST SE PROCEEDINGS: IEEE MICRO ELECTRO MECHANICAL SYSTEMS WORKSHOP LA English DT Proceedings Paper CT 12th IEEE International Conference on Micro Electro Mechanical Systems (MEMS 99) CY JAN 17-21, 1999 CL ORLANDO, FL SP IEEE Robot & Automat Soc AB We bonded gold on silicon substrates (Au/Si) for a MEMS application by using microwave radiation in a single-mode cavity. Microwave radiation selectively heats materials; the energy is deposited in the metallic portion of the substrates in this application. This concentration of the energy forms the bonding rather quickly and with minimal heating of the substrate. The short bonding process- time allows for minimal diffusion of the Si into the metallization. Since no pressure is applied to form the bonding, mechanical stresses are minimized. The substrates bonded by our technique formed a hermetically sealed micro-cavity. Preliminary He leak-tests from these bonded samples show leak-rates on the order of 3x10(9) atom cc/s. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Budraa, NK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 15 Z9 15 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1084-6999 BN 0-7803-5195-9 J9 PROC IEEE MICR ELECT PY 1999 BP 490 EP 492 DI 10.1109/MEMSYS.1999.746877 PG 3 WC Automation & Control Systems; Engineering, Electrical & Electronic; Engineering, Mechanical; Optics SC Automation & Control Systems; Engineering; Optics GA BM43W UT WOS:000078743100086 ER PT S AU Lawton, RA Abraham, M Lawrence, E AF Lawton, RA Abraham, M Lawrence, E BE Lawton, RA Miller, WM Lin, G Ramesham, R TI Characterization of non-planar motion in MEMS involving scanning laser interferometery SO MEMS RELIABILITY FOR CRITICAL AND SPACE APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on MEMS Reliability for Critical and Space Applications CY SEP 21-22, 1999 CL SANTA CLARA, CA SP SPIE, SolidState Technol, Semicond Equipment & Mat Int, Natl Inst Sand & Technol, Sandia Natl Labs, Inst Elect Engineers Japan, Japan Soc Mech Engn, Reliabil Engn Assoc Japan AB A study to evaluate three processes used for the release of standard devices produced by MCNC using the MUMPS process was undertaken by Jet Propulsion Laboratory with the collaboration of The Aerospace Corporation, and Polytec PI. The processes used were developed at various laboratories and are commonly the final step in the production of micro-electro-mechanical systems prior to packaging. It is at this stage of the process when the devices become extremely delicate and are subject to yield losses due to handling errors or the phenomenon of stiction. The effects of post processing with HF on grain boundries and subsequent thermal processing producing native oxide growth during packaging will require further investigation. C1 CALTECH, Jet Prop Lab, MST Spaceflight Qualificat Lab, Pasadena, CA 91101 USA. RP Lawton, RA (reprint author), CALTECH, Jet Prop Lab, MST Spaceflight Qualificat Lab, 4800 Oak Grove Dr,MS 300-220, Pasadena, CA 91101 USA. 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 0-8194-3477-9 J9 P SOC PHOTO-OPT INS PY 1999 VL 3880 BP 46 EP 50 DI 10.1117/12.359370 PG 5 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Optics; Physics, Applied SC Engineering; Materials Science; Optics; Physics GA BP12V UT WOS:000084201200006 ER PT S AU Ramesham, R Ghaffarian, R Kim, NP AF Ramesham, R Ghaffarian, R Kim, NP BE Lawton, RA Miller, WM Lin, G Ramesham, R TI Reliability issues of COTS MEMS for aerospace applications SO MEMS RELIABILITY FOR CRITICAL AND SPACE APPLICATIONS SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on MEMS Reliability for Critical and Space Applications CY SEP 21-22, 1999 CL SANTA CLARA, CA SP SPIE, SolidState Technol, Semicond Equipment & Mat Int, Natl Inst Sand & Technol, Sandia Natl Labs, Inst Elect Engineers Japan, Japan Soc Mech Engn, Reliabil Engn Assoc Japan DE commercial-off-the-shelf; COTS; microelectromechanical systems; MEMS; reliability; pressure sensors; accelerometer; and aerospace environment ID SENSORS AB During the last decade, research and development of microelectromechanical systems (MEMS) has shown a significant promise for a variety of commercial applications including automobile and medical purposes. For example, accelerometers are widely used for air bag in automobile and pressure sensors for various industrial applications. Same of the MEMS devices have potential to become the commercial-off-the-shelf (COTS) components. While high reliability applications including aerospace require much more sophisticated technology development, they would achieve significant cost savings if they could utilize COTS components in their systems. This paper reviews the current status of MEMS packaging technology from COTS to specific application provides lessons learned, and finally, identifies a need for a systematic approach for this purpose. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ramesham, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 125-152, Pasadena, CA 91109 USA. EM Rajeshuni.Ramesham@jpl.nasa.gov NR 35 TC 5 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 0-8194-3477-9 J9 PROC SPIE PY 1999 VL 3880 BP 83 EP 88 DI 10.1117/12.359357 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Optics; Physics, Applied SC Engineering; Materials Science; Optics; Physics GA BP12V UT WOS:000084201200011 ER PT S AU Man, KF AF Man, KF BE Lawton, RA Miller, WM Lin, G Ramesham, R TI MEMS reliability for space applications by elimination of potential failure modes through testing and analysis SO MEMS RELIABILITY FOR CRITICAL AND SPACE APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on MEMS Reliability for Critical and Space Applications CY SEP 21-22, 1999 CL SANTA CLARA, CA SP SPIE, SolidState Technol, Semicond Equipment & Mat Int, Natl Inst Sand & Technol, Sandia Natl Labs, Inst Elect Engineers Japan, Japan Soc Mech Engn, Reliabil Engn Assoc Japan DE MEMS devices; reliability; qualification; failure mode; test; analysis; modeling; space environments; mitigation ID MICROELECTROMECHANICAL SYSTEMS MEMS; SILICON; ADHESION; ACCELEROMETERS; FRICTION; SURFACES AB As the design of Micro-Electro-Mechanical System (MEMS) devices matures and their application extends to critical areas, the issues of reliability and long-term survivability become increasingly important. This paper reviews some general approaches to addressing the reliability and qualification of MEMS devices for space applications. The failure modes associated with different types of MEMS devices that are likely to occur, not only under normal terrestrial operations, but also those that are encountered in the harsh environments of space, will be identified. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Man, KF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 29 TC 9 Z9 9 U1 0 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3477-9 J9 P SOC PHOTO-OPT INS PY 1999 VL 3880 BP 120 EP 129 DI 10.1117/12.359361 PG 10 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Optics; Physics, Applied SC Engineering; Materials Science; Optics; Physics GA BP12V UT WOS:000084201200015 ER PT S AU Jackman, CH Fleming, EL Vitt, FM Considine, DB AF Jackman, CH Fleming, EL Vitt, FM Considine, DB BE Rottger, J Fukao, S Krivolutsky, A TI The influence of solar proton events on the ozone layer SO MESOPAUSE AND EXTRA-TERRESTRIAL INFLUENCES ON THE OZONE LAYER SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C2 1 and C2 2 Symposia of COSPAR Scientific Commission C Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Sci Comm Solar Terr Phys, Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Int Union Radio Sci, Comm Space Res, Int Union Geodesy & Geophys, Int Assoc Meteorol & Atmospher Sci ID MIDDLE ATMOSPHERE; 2-DIMENSIONAL MODEL; OCTOBER 1989 AB Our two-dimensional chemistry and transport atmospheric model was used to simulate the influence of solar proton events (SPEs) over the 1965 to 1995 time period. Extremely large particle events with huge fluxes of very high energy protons occurred in August 1972 and October 1989 and caused large increases in long-lived NOy constituents, which affected ozone for several months to years past the events. Our simulations show that the SPE-produced NOy constituents in the upper stratosphere caused direct ozone losses. However, interference of the NOy constituents with the halogen loss cycles for ozone destruction actually led to some total ozone production. We predict a seasonal dependence for the impact on polar ozone, with larger (smaller) decreases predicted for SPEs occurring in the fall or winter (spring or summer). (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Applicat Corp, Vienna, VA 22180 USA. NOAA, Sterling Software, SEC, Boulder, CO 80303 USA. Univ Maryland, Dept Meteorol, Joint Ctr Earth Syst Sci, College Pk, MD 20742 USA. RP Jackman, CH (reprint author), NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA. RI Jackman, Charles/D-4699-2012 NR 11 TC 13 Z9 13 U1 2 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 5 BP 625 EP 630 DI 10.1016/S0273-1177(99)00481-0 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP17N UT WOS:000084313200013 ER PT J AU Pilcher, CB AF Pilcher, CB TI "Martian Meteorites: Where Do We Stand and Where are We Going?" Houston, Texas - 1998 November 2-4 SO METEORITICS & PLANETARY SCIENCE LA English DT Editorial Material C1 NASA, Washington, DC 20546 USA. RP Pilcher, CB (reprint author), NASA, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 1999 VL 34 IS 1 BP 3 EP 4 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 161QX UT WOS:000078301400002 ER PT J AU Ghaffarian, R Kim, NP AF Ghaffarian, R Kim, NP TI Ball grid array reliability assessment for aerospace applications SO MICROELECTRONICS RELIABILITY LA English DT Article AB Reliability of ball grid arrays (BGAs) was evaluated with special emphasis on space applications. This work was performed as part of a consortium led by the Jet Propulsion Laboratory (JPL) to help build the infrastructure necessary for implementing this technology. Nearly 200 test vehicles, each with four package types, were assembled and tested using an experiment design. The most critical variables incorporated in this experiment were package type, board material, surface finish, solder volume, and environmental condition. The packages used for this experiment were commercially available packages with over 250 I/Os including both plastic and ceramic EGA packages. The test vehicles were subjected to thermal and dynamic environments representative of aerospace applications. Two different thermal cycling conditions were used, the JPL cycle ranged from -30 degrees C to 100 degrees C and the Boeing cycle ranged from -55 degrees C to 125 degrees C. The test vehicles were monitored continuously to detect electrical failure and their failure mechanisms were characterized. They were removed periodically for optical inspection, scanning electron microscopy (SEM) evaluation, and cross-sectioning for crack propagation mapping. Data collected from both facilities were analyzed and fitted to distributions using the Weibull distribution and Coffin-Manson relationships for failure projection. This paper will describe experiment results as well as those analyses. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Boeing Def & Space Grp, Seattle, WA USA. RP Ghaffarian, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 10 Z9 10 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD JAN PY 1999 VL 39 IS 1 BP 107 EP 112 DI 10.1016/S0026-2714(98)00185-1 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 180LL UT WOS:000079387400013 ER PT J AU Subramanian, RS Zhang, L Balasubramaniam, R AF Subramanian, RS Zhang, L Balasubramaniam, R TI Mass transport from a drop executing thermocapillary motion SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article ID LARGE MARANGONI NUMBERS; MIGRATION AB The problem of mass transport from a drop to a continuous phase is posed when the drop is executing thermocapillary migration. Solutions ave obtained in two limiting cases via asymptotic analyses. In the first, convective transport of species plays a small role compared with molecular transport, implying that the compositional Peclet number Pe is small. In this case, using the method of matched asymptotic expansions, the concentration field is obtained to O(Pe(3)). In the opposite limiting case, wherein the Peclet number is large, the solution of the leading order boundary layer problem is given. In both situations, results are provided for the quasi-steady Sherwood number and the time evolution of the radius of a pure component drop. C1 Clarkson Univ, Dept Chem Engn, Potsdam, NY 13699 USA. Corning Inc, Corning, NY 14831 USA. NASA, Glenn Res Ctr, Natl Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. RP Subramanian, RS (reprint author), Clarkson Univ, Dept Chem Engn, Potsdam, NY 13699 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 86 04 20, D-81679 MUNICH, GERMANY SN 0938-0108 J9 MICROGRAVITY SCI TEC JI Microgravity Sci. Technol. PY 1999 VL 12 IS 3-4 BP 107 EP 115 PG 9 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA 443YD UT WOS:000169370400004 ER PT S AU Desai, U Orwig, L Clark, D Appleby, M AF Desai, U Orwig, L Clark, D Appleby, M BE Smith, JH Karam, JM TI New fabrication methodology for fine feature-high aspect ratio structures made from high Z materials SO MICROMACHINING AND MICROFABRICATION PROCESS TECHNOLOGY V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Micromachining and Microfabrication Process Technology V CY SEP 20-22, 1999 CL SANTA CLARA, CA SP SPIE, SolidState Technol, Semicond Equipment & Mat Int, Natl Inst Stand & Technol, Sandia Natl Labs, Inst Elect Engineers Japan, Japan Soc Mech Engn, Reliabil Engn Assoc Japan DE coded apertures; collimators; imaging; x-rays AB Radiological imaging relies heavily on collimators to achieve diagnostic x-ray images. These collimating structures are required due to the lack of efficient x-ray reflectors or refractors needed to make lenses or mirrors. In order to achieve higher resolution x-ray images, finer collimator geometries are needed. The two critical parameters that define the fineness of a collimator are the length of the collimator structure and the aperture size. Current collimator fabrication technology provides structures with coarse cell sizes, which require long structural lengths, to achieve image optimization. Finer collimator. geometries would help reduce the overall length of collimating structures. Tecomet, of Woburn, MA has developed a new technology to fabricate fine-featured, high aspect ratio structures made from high Z materials. These collimating structures have been made from tungsten with aspect ratios above 50:1 and geometry features less than 20 microns. This technology has enabled advancements in the design of x-ray coded apertures. This has opened the door to new ideas for x-ray imaging. Optimized coders, made from tungsten, can now be designed and fabricated to achieve very high angular resolution. Significant reduction in weigh is realized due to the reduction in collimator thickness. The collimators made using these fabrication methods also provide greater long-term structural stability compared to collimators used in diagnostic x-ray imaging using lead. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Desai, U (reprint author), NASA, Goddard Space Flight Ctr, Code 682, Greenbelt, MD 20771 USA. NR 3 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 0-8194-3471-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3874 BP 321 EP 329 DI 10.1117/12.361236 PG 9 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Optics; Physics, Applied SC Engineering; Materials Science; Optics; Physics GA BP12R UT WOS:000084199900035 ER PT S AU Li, MJ Allen, CA Gordon, SA Kuhn, JL Mott, DB Stahle, CK Wang, LQL AF Li, MJ Allen, CA Gordon, SA Kuhn, JL Mott, DB Stahle, CK Wang, LQL BE Smith, JH Karam, JM TI Fabrication of pop-up detector arrays on Si wafers SO MICROMACHINING AND MICROFABRICATION PROCESS TECHNOLOGY V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Micromachining and Microfabrication Process Technology V CY SEP 20-22, 1999 CL SANTA CLARA, CA SP SPIE, SolidState Technol, Semicond Equipment & Mat Int, Natl Inst Stand & Technol, Sandia Natl Labs, Inst Elect Engineers Japan, Japan Soc Mech Engn, Reliabil Engn Assoc Japan DE pop-up detectors; microfabrification; photolithography; silicon wafers; anisotropic etching ID FRACTURE; SILICON AB High sensitivity is a basic requirement for a new generation of thermal detectors. To meet the requirement, close-packed, two-dimensional silicon detector arrays have been developed in NASA Goddard Space Flight Center. The goal of the task is to fabricate detector arrays configured with thermal detectors such as infrared bolometers and x-ray calorimeters to use in space flight missions. This paper focuses on the fabrication and the mechanical testing of detector arrays in a 0.2 mm pixel size, the smallest pop-up detectors being developed so far. These array structures, nicknamed "PUDs" for "Pop-Up Detectors", are fabricated on 1 mu m thick, single-crystal, silicon membranes. Their designs have been refined so we can utilize the flexibility of thin silicon films by actually folding the silicon membranes to 90 degrees in order to obtain close-packed two-dimensional arrays. The PUD elements consist of a detector platform and two legs for mechanical support while also serving as electrical and thermal paths. Torsion bars and cantilevers connecting the detector platform to the legs provide additional flexures for strain relief. Using micro-electromechanical structure (MEMS) fabrication techniques, including photolithography, anisotropic chemical etching, reactive-ion etching, and laser dicing, we have fabricated PUD detector arrays of fourteen designs with a variation of four parameters including cantilever length, torsion bar length and width, and leg length. Folding tests were conducted to test mechanical stress distribution for the array structures. We obtained folding yields and selected optimum design parameters to reach minimal stress levels. Computer simulation was also employed to verify mechanical behaviors of PUDs in the folding process. In addition, scanning electron microscopy was utilized to examine the flatness of detectors and the alignment of detector pixels in arrays. The fabrication of thermistors and heaters on the pop-up detectors is under way, preparing us for the next step of the experiment, the thermal test. C1 NASA, GSFC, STX, Raytheon Corp, Greenbelt, MD 20770 USA. RP Li, MJ (reprint author), NASA, GSFC, STX, Raytheon Corp, Greenbelt, MD 20770 USA. NR 9 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 0-8194-3471-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3874 BP 422 EP 431 DI 10.1117/12.361247 PG 10 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Optics; Physics, Applied SC Engineering; Materials Science; Optics; Physics GA BP12R UT WOS:000084199900045 ER PT S AU Pickett, JS Gurnett, DA Menietti, JD LeDocq, MJ Scudder, JD Frank, LA Sigwarth, JB Ackerson, KL Morgan, DD Franz, JR Kintner, PM Tsurutani, BT Ho, CM Chen, J Fritz, TA Russell, CT Peterson, WK Kasahara, Y Kimura, I Watanabe, S Arkos, GG Rostoker, G Kokubun, S Fukunishi, H Pfaff, RF Mozer, FS Hsieh, SY Mukai, T Chandler, MO AF Pickett, JS Gurnett, DA Menietti, JD LeDocq, MJ Scudder, JD Frank, LA Sigwarth, JB Ackerson, KL Morgan, DD Franz, JR Kintner, PM Tsurutani, BT Ho, CM Chen, J Fritz, TA Russell, CT Peterson, WK Kasahara, Y Kimura, I Watanabe, S Arkos, GG Rostoker, G Kokubun, S Fukunishi, H Pfaff, RF Mozer, FS Hsieh, SY Mukai, T Chandler, MO BE Matsumoto, H Omura, Y TI Plasma waves observed during cusp energetic particle events and their correlation with Polar and Akebono satellite and ground data SO MICROSCOPIC PROCESSES IN SPACE PLASMAS AND THEIR ROLE IN MACROSCALE PHENOMENA SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT Symposium D0 2 of COSPAR Scientific Commission D held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Union Radio Sci, Comm Space Res ID ELECTRIC-FIELD STRUCTURES; WHISTLER-MODE WAVES; EXOS-D SATELLITE; LION ROARS; GEOTAIL OBSERVATIONS; ELECTROSTATIC NOISE; SPACECRAFT; FREQUENCY; MAGNETOSHEATH; INSTRUMENT AB We present Polar plasma wave data during cusp energetic particle (CEP) events at 6-9 R-E. These data suggest the presence of coherent electrostatic structures that are highly localized and that have typical velocities on the order of hundreds to thousands of km/s along the ambient magnetic field. Some of the wave signatures are solitary waves and some are wave packets. The Polar wave instrument also provides evidence that some of the bursts of electromagnetic waves (with frequencies of a few hundred Hz and just below the electron cyclotron frequency around 800 Hz to 1-2 kHz) that are observed are coherent and propagating both up and down the field lines. Electron cyclotron harmonic (ECH) waves are often detected but their duration is usually short (< 1 s). Low Frequency (< 1 kHz), broadband, bursty electromagnetic waves are also present. The Polar wave data results are used to obtain a better understanding of the macro/microphysics during a CEP event that takes place on September 11, 1996, by correlating various Polar (similar to 7.0 R-E) and Akebono (similar to 1.4 R-E) data while both spacecraft are in or near the cusp/cleft region and nearly on the same field line, and magnetometer data from the Canadian Intermagnet and Canopus ground stations, which lie near the base of the magnetic footprint passing through Polar. Solar wind and magnetic field data from the interplanetary medium and magnetosheath are provided by the Geotail and IMP-8 satellites, respectively. Some of the cusp waves may be indicators of the reconnection process taking place through the cusp, the result of mixing of magnetosheath with magnetospheric plasma, and the consequence of an anisotropic electron population in a depressed magnetic field. The low frequency electromagnetic waves are still under study to determine their role, if any, in the heating and acceleration of the MeV He ions during CEP events. (C) 1999 COSPAR, Published by Elsevier Science Ltd. C1 Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Cornell Univ, Sch Elect Engn, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Lockheed Martin Palo Alto Res Lab, Palo Alto, CA 94304 USA. Kyoto Univ, Grad Sch Elect & Commun, Kyoto 60601, Japan. Osaka Inst Technol, Osaka 535, Japan. Tohoku Univ, Dept Geophys, Sendai, Miyagi 980, Japan. Univ Calgary, Inst Space Res, Calgary, AB T2N 1N4, Canada. Nagoya Univ, Solar Terr Environm Lab, Aichi 442, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alberta, Dept Phys, Edmonton, AB T6G 2J1, Canada. RP Pickett, JS (reprint author), Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. RI Pfaff, Robert/F-5703-2012; Scudder, Jack/D-8417-2013; Peterson, WK/A-8706-2009; OI Pfaff, Robert/0000-0002-4881-9715; Scudder, Jack/0000-0001-7975-5630; Peterson, WK/0000-0002-1513-6096; Russell, Christopher/0000-0003-1639-8298 NR 38 TC 25 Z9 25 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 24 IS 1 BP 23 EP 33 DI 10.1016/S0273-1177(99)00418-4 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN87R UT WOS:000083308000003 ER PT B AU Kogut, A AF Kogut, A BE DeOliveiraCosta, A Tegmark, M TI Anomalous microwave emission SO MICROWAVE FOREGROUNDS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Microwave Foregrounds CY NOV 14-15, 1998 CL INST ADV STUDY, PRINCETON, NJ SP Alfred P Sloan Fdn HO INST ADV STUDY ID H-ALPHA EMISSION; GALACTIC EMISSION; INFRARED CIRRUS; SKY MAPS; RADIOMETER; RADIATION; COMPONENT; SCALES; DUST AB Improved knowledge of diffuse Galactic emission is important to maximize the scientific return from scheduled CMB anisotropy missions. Cross-correlation of microwave maps with maps of the far-IR dust continuum show a ubiquitous microwave emission component whose spatial distribution is traced by far-IR dust emission. The spectral index of this emission, beta(radio) = -2.2(-0.7)(+0.5), is suggestive of free-free emission but does not preclude other candidates. Comparison of H alpha and microwave results show that both data sets have positive correlations with the far-IR dust emission. Microwave data: however, are consistently brighter than can be explained solely from free-free emission traced by H alpha. This "anomalous" microwave emission can be explained as electric dipole radiation from small spinning dust grains. The anomalous component at 53 GHz is 2.5 times as bright as the free-free emission traced by Her, providing an approximate normalization for models with significant spinning dust emission. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Kogut, A (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 685, Greenbelt, MD 20771 USA. NR 24 TC 13 Z9 13 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-006-4 J9 ASTR SOC P PY 1999 VL 181 BP 91 EP 99 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN98N UT WOS:000083761100004 ER PT S AU Ksendzov, A Martin, RD Modarress, D Gharib, M AF Ksendzov, A Martin, RD Modarress, D Gharib, M BE Motomedi, ME Goering, R TI Miniature illuminator for laser Doppler velocimeter assembled on micromachined silicon optical bench SO MINIATURIZED SYSTEMS WITH MICRO-OPTICS AND MEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Miniaturized Systems with Micro-Optics and MEMS CY SEP 20-22, 1999 CL SANTA CLARA, CA SP SPIE, SolidState Technol, Semicond Equipment & Mat Int, Natl Inst Stand & Technol, Sandia Natl Labs, Inst Elect Engineers Japan, Japan Soc Mech Engn, Reliabil Engn Assoc Japan DE Doppler velocimeter; anemometer; micromachined; silicon optical bench AB We have built a miniature illuminator for Laser Doppler velocimeter on micromachined silicon optical bench utilizing a novel optical scheme. We used two intersecting coherent beams from the two opposing facets of semiconductor laser die to form a standing interference pattern needed for the particle detection and velocity measurement. Such devices are of interest to NASA for investigating wind patterns and dust loading on planets with atmosphere. They have been applied to problems where the liquid or gas flux must be characterized without disturbing the flow. In addition, the small probe volume makes possible local flow characterization and profiling. The device fabrication, and the results of the fringe characterization and velocity measurements are presented and discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ksendzov, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 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 0-8194-3475-2 J9 P SOC PHOTO-OPT INS PY 1999 VL 3878 BP 304 EP 309 DI 10.1117/12.361273 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BP12U UT WOS:000084201000033 ER PT B AU Ellis, SR Menges, BM AF Ellis, SR Menges, BM BE Ohta, Y Tamura, H TI Operator localization of virtual objects SO MIXED REALITY: MERGING REAL AND VIRTUAL WORLDS LA English DT Proceedings Paper CT 1st International Symposium on Mixed Reality (ISMR 99) CY MAR, 1999 CL YOKOHAMA, JAPAN ID DISTANCE TENDENCY 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 16 TC 1 Z9 1 U1 0 U2 0 PU OHMSHA LTD PI TOKYO PA 1-3 KANDA NISHIKI-CHO, CHIYODA-KU, TOKYO, 101, JAPAN BN 4-274-90283-8 PY 1999 BP 305 EP 323 PG 19 WC Computer Science, Information Systems SC Computer Science GA BR63K UT WOS:000166990100020 ER PT S AU Jones, JA Wu, JJ AF Jones, JA Wu, JJ BE Gage, DW Choset, HM TI Inflatable rovers for planetary applications SO MOBILE ROBOTS XIV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Mobile Robots XIV CY SEP 20-22, 1999 CL BOSTON, MA SP SPIE DE robotics; rover; planetary; Mars; Titan; inflatable AB A new task has recently been initiated at the Jet Propulsion Laboratory (JPL) to design, fabricate and test an inflatable rover that can be used for various planetary applications, including operation on the Earth's moon, on Mars, on Saturn's moon Titan and on Jupiter's moon, Europa. The primary application is for operation on Mars and, as such, the prototype model in development has large inflatable wheels (1.5-m diameter) that can traverse over 99 percent of the Martian surface, which is believed to be populated by rocks smaller than 0.5 meters in diameter. The 20-kg prototype requires 18 W to travel 2 km/hr on Earth, and could be capable of traveling 30 km/hr on Mars with about 100 W of power. The bench-model unit has been tested with a simple 'joy stick' type of radio control system as well as with a commercially available color-tracking camera system. C1 CALTECH, Jet Prop Lab, Div Appl Mech 35, Pasadena, CA 91109 USA. RP Jones, JA (reprint author), CALTECH, Jet Prop Lab, Div Appl Mech 35, M-S 157-316, Pasadena, CA 91109 USA. NR 7 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 0-8194-3431-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3838 BP 63 EP 68 DI 10.1117/12.369242 PG 6 WC Automation & Control Systems; Optics SC Automation & Control Systems; Optics GA BP12H UT WOS:000084182400007 ER PT B AU Owen, WM Synnott, SP Null, GW AF Owen, WM Synnott, SP Null, GW BE Dvorak, R Haupt, HF Wodnar, K TI High-accuracy asteroid astrometry from table mountain observatory SO MODERN ASTROMETRY AND ASTRODYNAMICS LA English DT Proceedings Paper CT International Conference on Modern Astrometry and Astrodynamics Honoring Heinrich Eichhorn CY MAY 25-26, 1998 CL VIENNA OBSERVATORY, VIENNA, AUSTRIA HO VIENNA OBSERVATORY DE astrometry; asteroids; CCD; reduction techniques ID EXTRAGALACTIC REFERENCE FRAME; ATMOSPHERIC LIMITATIONS; POSITIONS AB We have installed a large-format CCD camera on the 0.6-meter telescope at JPL's Table Mountain Observatory and used it to obtain high-accuracy astrometric observations of asteroids and other solar system targets of interest. The detector contains 4096x 4096 15-mu m pixels and produces a field of view 21'.9 square at a resolution of 0 ".321/pixel. The field is wide enough to obtain sufficient reference stars from the ACT Catalog, and the oversampled images can produce centroids to a precision of 10-30 milliarcseconds. We describe the calibration and reduction procedures, including routine use of the overlapping field technique, that are necessary in order to obtain an accurate mapping of distortions in the focal plane. Our observations have enabled a successful flyby of 253 Mathilde, predicted ground tracks for several asteroid occultations, and will support onboard autonomous navigation for the Deep Space One mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Owen, WM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 29 TC 0 Z9 0 U1 0 U2 0 PU VERLAG OSTERREICHISCHEN AKAD WISSENSCHAFTEN PI VIENNA PA DR IGNAY-SEIPEL-PLATZ 2, A-1010 VIENNA, AUSTRIA BN 3-7001-2774-X PY 1999 BP 89 EP 101 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN17D UT WOS:000080928900009 ER PT B AU Standish, EM Nobili, AM AF Standish, EM Nobili, AM BE Dvorak, R Haupt, HF Wodnar, K TI The observations of Galileo SO MODERN ASTROMETRY AND ASTRODYNAMICS LA English DT Proceedings Paper CT International Conference on Modern Astrometry and Astrodynamics Honoring Heinrich Eichhorn CY MAY 25-26, 1998 CL VIENNA OBSERVATORY, VIENNA, AUSTRIA HO VIENNA OBSERVATORY DE Galileo; Neptune AB A truly startling discovery was found by Stillman Drake and Charles Kowal when they were studying the observations of the astronomer Galileo. That discovery is related here, and the implications which it has for modern-day astronomy are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Standish, EM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,301-150, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU VERLAG OSTERREICHISCHEN AKAD WISSENSCHAFTEN PI VIENNA PA DR IGNAY-SEIPEL-PLATZ 2, A-1010 VIENNA, AUSTRIA BN 3-7001-2774-X PY 1999 BP 151 EP 158 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN17D UT WOS:000080928900015 ER PT J AU McMurry, AD Jordan, C Carpenter, KG AF McMurry, AD Jordan, C Carpenter, KG TI The outer atmosphere of alpha Tau - II. Fluorescent lines SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE line : formation; stars : atmospheres; stars : chromospheres; stars : individual : alpha Tau ID LATE-TYPE STARS; FE-II; CARBON-MONOXIDE; EXCITATION; SPECTRA; H-2; CO AB The Goddard High Spectrograph (GHRS) on the Hubble Space Telescope has been used to observe alpha Tau (K5 III). The resulting spectra contain many sharp fluorescent lines. Most of these have been identified as lines of Fe II, Ca II and H-2, radiatively excited by H Ly alpha. The chromospheric model developed in an accompanying paper has been used to calculte the fluxes in these lines. The Ca II lines have been modelled with a full radiative transfer calculation, but the Fe II and H-2 systems are more complex and, for these, a simpler calculation has been made. Overall, the trend in the Fe II line fluxes provides evidence for a multi-component model of the atmosphere, a chromosphere with intrusions of hotter material or vice versa. The hotter material could be in shocks propagating through the chromosphere. Comparisons of the observed and calculated fluxes of individual lines of Fe II show that some atomic data need to be improved. The analysis of the H-2 lines is restricted by a lack of suitable molecular data. The two observed CA II lines are reproduced to within a factor of 2. C1 Univ Oxford, Dept Phys Theoret Phys, Oxford OX1 3NP, England. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP McMurry, AD (reprint author), Univ Oxford, Dept Phys Theoret Phys, 1 Keble Rd, Oxford OX1 3NP, England. RI Carpenter, Kenneth/D-4740-2012 NR 30 TC 17 Z9 17 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JAN 1 PY 1999 VL 302 IS 1 BP 48 EP 58 DI 10.1046/j.1365-8711.1999.02077.x PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162GB UT WOS:000078336600011 ER PT J AU Clark, JS Lyuty, VM Zaitseva, GV Larionov, VM Larionova, LV Finger, M Tarasov, AE Roche, P Coe, MJ AF Clark, JS Lyuty, VM Zaitseva, GV Larionov, VM Larionova, LV Finger, M Tarasov, AE Roche, P Coe, MJ TI Long-term variability of the Be/X-ray binary A0535+26 - 3. Photometry SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE accretion, accretion discs; binaries : close; circumstellar matter; stars : emission-line, Be; stars : individual : A0535+26; X-rays : stars ID IRAS OBSERVATIONS; STARS; BEHAVIOR AB UBV-band photometric observations of the Be/X-ray binary system HDE 245770/A0535+26 over the last decade are presented. It is shown that the emission at all wavelengths is correlated, and that no resolvable time-lag exists between variations in differing wavebands, This is suggestive of emission from only one source within the system. It is found that the optical continuum can be understood as optically thin free-free and bound-free emission from material in the circumstellar disc around the primary Oe star. We find a change in the emission measure of the disc by a factor of similar to 40 over the course of the observations. If this is interpreted as a variation in the mass-loss rate from the primary, it corresponds to a change by a factor of similar to 6. Period searches on the optical light curve reveal no evidence for modulation of the circumstellar envelope at the orbital period; therefore it seems unlikely that the mass-loss rate from the primary is affected by the neutron star at periastron. No positive correlation exists between the optical and X-ray light curves; such a result appears to exclude models for the X-ray behaviour in which accretion is directly fed from the dense circumstellar wind of the primary. It is likely that X-ray outbursts are instead triggered by discrete mass ejection events from the primary. C1 Univ Sussex, Ctr Astron, CPES, Brighton BN1 9QH, E Sussex, England. Univ Southampton, Dept Phys, Southampton SO17 1BJ, Hants, England. Moscow State Univ, Sternberg Astron Inst, Moscow, Russia. St Petersburg State Univ, Inst Astron, St Petersburg, Russia. NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Crimean Astrophys Observ, UA-334413 Nauchny, Crimea, Ukraine. RP Clark, JS (reprint author), Univ Sussex, Ctr Astron, CPES, Brighton BN1 9QH, E Sussex, England. RI Larionov, Valeri/H-1349-2013 OI Larionov, Valeri/0000-0002-4640-4356 NR 21 TC 30 Z9 31 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JAN 1 PY 1999 VL 302 IS 1 BP 167 EP 172 DI 10.1046/j.1365-8711.1999.02112.x PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 162GB UT WOS:000078336600023 ER PT S AU Matsumoto, K Heki, K Rowlands, DD AF Matsumoto, K Heki, K Rowlands, DD BE Ip, WH Foing, BH Masson, PL TI Impact of far-side satellite tracking on gravity estimation in the SELENE project SO MOON AND MARS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT Symposia B0 3 and B0 4 of COSPAR Scientific Commission B held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP NASA, Int Astronom Union, Inst Space & Astronaut Sci, Int Union Geodes & Geophys, Ctr Natl Etudes Spatiales, Comm Space Res ID LUNAR AB Preliminary results of numerical simulation are presented to examine the gravity estimation capability in the Japanese lunar exploration project SELENE (SELenological and ENgineering Explorer), which will be launched in 2003. One of the new characteristics of the SELENE lunar gravimetry is 4-way satellite-to-satellite Doppler tracking of a low-altitude lunar orbiter by means of a high-altitude relay satellite. It is shown that planned satellites configuration will provide a good far-side data coverage of the lunar orbiter and will improve lunar gravity field as well as far-side selenoid. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Natl Astron Observ, Div Earth Rotat, Mizusawa, Iwate 0230861, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Matsumoto, K (reprint author), Natl Astron Observ, Div Earth Rotat, 2-12 Hoshigaoka, Mizusawa, Iwate 0230861, Japan. RI Rowlands, David/D-2751-2012 NR 8 TC 8 Z9 9 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 11 BP 1809 EP 1812 DI 10.1016/S0273-1177(99)00542-6 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP01A UT WOS:000083814100002 ER PT S AU Kamata, Y Takeshima, T Okada, T Terada, K AF Kamata, Y Takeshima, T Okada, T Terada, K BE Ip, WH Foing, BH Masson, PL TI Detection of X-ray fluorescence line feature from the lunar surface SO MOON AND MARS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT Symposia B0 3 and B0 4 of COSPAR Scientific Commission B held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP NASA, Int Astronom Union, Inst Space & Astronaut Sci, Int Union Geodes & Geophys, Ctr Natl Etudes Spatiales, Comm Space Res ID BOARD ASCA; TELESCOPE AB We present the results of an analysis by ASCA (Japanese X-ray astronomy satellite) observation of the lunar surface on July 10th - 11th, 1993, In spite of the fact that the X-ray surface brightness is estimated to be at nearly CXB (Cosmic X-ray Background) level, the X-ray spectrum shows significant deviations in relation to Al-K alpha and Si-K alpha fluorescence X-rays, According to the intensity ratios of Al/Si (1-2) and Mg/Si (<0.4), the properties of the X-ray spectrum is consistent with an intermediate abundance ratio between highlands and mares (or relatively similar to highland values). However, the X-ray illuminated region on the lunar surface are mainly covered with mare regions and the emission of Al-K and Si-K fluorescence arises from both day side and night side region of the moon. These facts indicate the existence of X-ray production due to bremsstrahlung, with high energy particles impacting even on the night side. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Nagoya Univ, Res Ctr Adv Energy Convers, Chikusa Ku, Nagoya, Aichi 4648602, Japan. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Hiroshima Univ, Fac Sci, Dept Earth & Planetary Syst Sci, Hiroshima 739, Japan. RP Kamata, Y (reprint author), Nagoya Univ, Res Ctr Adv Energy Convers, Chikusa Ku, Furo Cho, Nagoya, Aichi 4648602, Japan. NR 16 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 11 BP 1829 EP 1832 DI 10.1016/S0273-1177(99)00539-6 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP01A UT WOS:000083814100007 ER PT S AU Ness, NF Acuna, MH Connerney, J Wasilewski, P Mazelle, C Sauvaud, J Vignes, D d'Uston, C Reme, H Lin, R Mitchell, DL McFadden, J Curtis, D Cloutier, P Bauer, SJ AF Ness, NF Acuna, MH Connerney, J Wasilewski, P Mazelle, C Sauvaud, J Vignes, D d'Uston, C Reme, H Lin, R Mitchell, DL McFadden, J Curtis, D Cloutier, P Bauer, SJ BE Ip, WH Foing, BH Masson, PL TI MGS magnetic fields and electron reflectometer investigation: Discovery of paleomagnetic fields due to crustal remanence SO MOON AND MARS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT Symposia B0 3 and B0 4 of COSPAR Scientific Commission B held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP NASA, Int Astronom Union, Inst Space & Astronaut Sci, Int Union Geodes & Geophys, Ctr Natl Etudes Spatiales, Comm Space Res ID MARTIAN BOW SHOCK; MARS; POSITION; SHAPE AB The MGS MAG/ER investigation provides vector measurements of the magnetic field and the ionospheric electron density near periapsis. The instrumentation consists of twin triaxial fluxgate magnetometers and a "top hat" electrostatic analyzer of electrons in the energy range of 1 eV to 20 keV. Results include extensive mapping of the detached bow shock wave in the solar wind, the nature: and structure of the ionopause and magnetic pile-up boundaries. The most surprising result is the discovery of localized magnetic fields of planetary origin, presumably clue to remanent crustal magnetization. Maximum fields measured while below the ionosphere exceed 300 nT. We present an initial study of one of these very localized fields and extrapolations to the Martian surface in the Acidalia planitia. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNRS, Ctr Ecol Ressources Renouvelables, F-31055 Toulouse, France. Univ Calif Berkeley, Berkeley, CA 94720 USA. Rice Univ, Houston, TX 77251 USA. Graz Univ, Graz, Austria. RP Ness, NF (reprint author), Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RI connerney, john/I-5127-2013; OI Bauer, Siegfried/0000-0003-4213-2047 NR 16 TC 24 Z9 23 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 11 BP 1879 EP 1886 DI 10.1016/S0273-1177(99)00271-9 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP01A UT WOS:000083814100017 ER PT S AU Bougher, S Keating, G Zurek, R Murphy, J Haberle, R Hollingsworth, J Clancy, RT AF Bougher, S Keating, G Zurek, R Murphy, J Haberle, R Hollingsworth, J Clancy, RT BE Ip, WH Foing, BH Masson, PL TI Mars Global Surveyor aerobraking: Atmospheric trends and model interpretation SO MOON AND MARS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT Symposia B0 3 and B0 4 of COSPAR Scientific Commission B held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP NASA, Int Astronom Union, Inst Space & Astronaut Sci, Int Union Geodes & Geophys, Ctr Natl Etudes Spatiales, Comm Space Res ID GENERAL-CIRCULATION; THERMOSPHERE; IONOSPHERE; VENUS; POLAR AB Mars Global Surveyor (MGS) recently obtained coordinated Power-atmosphere (thermal and dust) measurements and simultaneous upper atmosphere accelerometer data (densities, scale heights and temperatures) for the purpose of safely aerobraking the spacecraft toward its mapping orbit (Keating et al. 1998). Much useful scientific information was also gleaned that describes the coupling of these atmospheric regions during this Phase I aerobraking period (September 1997-March 1998; Ls = 184-300). The major features of this aerobraking data are presented, and its trends elucidated in order to : (1) illustrate the aerobraking environment experienced by the spacecraft, and (2) decompose the processes responsible for the atmospheric variations observed. Coupled general circulation models of the Mars lower and upper atmospheres are exercised to investigate the solar-orbital, seasonal, wave, and dust variations observed during MGS aerobraking. The precession of the MGS periapsis position during Phase I permits longitudinal, latitudinal, local time, and vertical variations of the thermosphere to be monitored. Future aerobraking activities at Mars will benefit greatly from this MGS aerobraking data and its model interpretation. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. George Washington Univ, NASA Langley, Newport News, VA 23606 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. New Mexico State Univ, Las Cruces, NM 88003 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Space Sci Inst, Boulder, CO 80309 USA. RP Bougher, S (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RI Bougher, Stephen/C-1913-2013 OI Bougher, Stephen/0000-0002-4178-2729 NR 16 TC 44 Z9 44 U1 1 U2 5 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 11 BP 1887 EP 1897 DI 10.1016/S0273-1177(99)00272-0 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP01A UT WOS:000083814100018 ER PT S AU Harri, AM Marsal, O Lognonne, P Leppelmeier, GW Spohn, T Glassmeier, KH Angrilli, F Banerdt, WB Barriot, JP Bertaux, JL Berthelier, JJ Calcutt, S Cerisier, JC Crisp, D Dehant, V Giardini, D Jaumann, R Langevin, Y Menvielle, M Musmann, G Pommereau, JP Di Pippo, S Guerrier, D Kumpulainen, K Larsen, S Mocquet, A Polkko, J Runavot, J Schumacher, W Siili, T Simola, J Tillman, JE AF Harri, AM Marsal, O Lognonne, P Leppelmeier, GW Spohn, T Glassmeier, KH Angrilli, F Banerdt, WB Barriot, JP Bertaux, JL Berthelier, JJ Calcutt, S Cerisier, JC Crisp, D Dehant, V Giardini, D Jaumann, R Langevin, Y Menvielle, M Musmann, G Pommereau, JP Di Pippo, S Guerrier, D Kumpulainen, K Larsen, S Mocquet, A Polkko, J Runavot, J Schumacher, W Siili, T Simola, J Tillman, JE CA NetLander Team BE Ip, WH Foing, BH Masson, PL TI Network science landers for Mars SO MOON AND MARS SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT Symposia B0 3 and B0 4 of COSPAR Scientific Commission B held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP NASA, Int Astronom Union, Inst Space & Astronaut Sci, Int Union Geodes & Geophys, Ctr Natl Etudes Spatiales, Comm Space Res ID TERRESTRIAL PLANETS; BOUNDARY-LAYER; PATHFINDER; SURFACE; MANTLE; WINDS; METEOROLOGY; SEISMOLOGY; MODELS; FLOW AB The NetLander Mission will deploy four landers to the Martian surface. Each lander includes a network science payload with instrumentation for studying the interior of Mars, the atmosphere and the subsurface, as well as the ionospheric structure and geodesy. The NetLander Mission is the first planetary mission focusing on investigations of the interior of the planet and the large-scale circulation of the atmosphere. A broad consortium of national space agencies and research laboratories will implement the mission. It is managed by CNES (the French Space Agency), with other major players being FMI (the Finnish Meteorological Institute), DLR (the German Space Agency), and other research institutes. According to current plans, the NetLander Mission will be launched in 2005 by means of an Ariane V launch, together with the Mars Sample Return mission. The landers will be separated from the spacecraft and targeted to their locations on the Martian surface several days prior to the spacecraft's arrival at Mars. The landing system employs parachutes and airbags. During the baseline mission of one Martian year, the network payloads will conduct simultaneous seismological, atmospheric, magnetic, ionospheric, geodetic measurements and ground penetrating radar mapping supported by panoramic images. The payloads also include entry phase measurements of the atmospheric vertical structure. The scientific data could be combined with simultaneous observations of the atmosphere and surface of Mars by the Mars Express Orbiter that is expected to be functional during the NetLander Mission's operational phase. Communication between the landers and the Earth would take place via a data relay onboard the Mars Express Orbiter. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Ctr Natl Etud Spatiales, CNES, F-31055 Toulouse, France. Inst Phys Globe Paris, Dep Etudes Spatiales, F-94107 St Maur, France. Tech Univ Carolo Wilhelmina Braunschweig, Inst Geophys, D-38106 Braunschweig, Germany. Univ Padua, I-35131 Padua, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Observ Midi Pyrenees, F-31400 Toulouse, France. CNRS Reduit Verriere, Serv Aeron, F-91371 Verrieres Le Buisson, France. CETP, F-94107 St Maur, France. Univ Oxford, Dept Atmospher Ocean & Plantet Phys, Oxford OX1 3PU, England. Observ Royal Belgique, B-1180 Brussels, Belgium. ASI, Italian Space Agency, Rome, Italy. ETH Honggerberg, Inst Geophys, CH-8093 Zurich, Switzerland. Aerospace Inc, F-33165 St Medard Zalles, France. DLR, Inst Planetary Explorat, Sect Planetary Geol, D-12489 Berlin, Germany. Space Syst Finland Ltd, Espoo 02200, Finland. Univ Paris 11, Inst Astrophys, F-91405 Orsay, France. Risoe Natl Lab, Roskilde, Denmark. RST, Rostock Raumfahrt & Umwellschutz Ltd, D-18119 Warnemunde, Germany. Finavitec Syst, Tampere 44100, Finland. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Munster, Inst Planetol, D-4400 Munster, Germany. Univ Nantes, Lab Geophys & Planetol, F-44322 Nantes, France. RP Finnish Meteorol Inst, Box 503, FIN-00101 Helsinki, Finland. RI Giardini, Domenico/F-5406-2011; Lognonne, Philippe/F-8846-2010; Harri, Ari-Matti/C-7142-2012; OI Harri, Ari-Matti/0000-0001-8541-2802; Calcutt, Simon/0000-0002-0102-3170 NR 49 TC 31 Z9 31 U1 0 U2 8 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 1999 VL 23 IS 11 BP 1915 EP 1924 DI 10.1016/S0273-1177(99)00279-3 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP01A UT WOS:000083814100023 ER PT S AU Ming, DW Allen, ER AF Ming, DW Allen, ER BE Misaelides, P Macasek, F Pinnavaia, TJ Colella, C TI Zeoponic substrates for space applications: Advances in the use of natural zeolites for plant growth SO NATURAL MICROPOROUS MATERIALS IN ENVIRONMENTAL TECHNOLOGY SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES E, APPLIED SCIENCES LA English DT Proceedings Paper CT Conference of the NATO Advanced Research Workshop on the Application of Natural Microporous Materials in Environmental Technology CY OCT 26-30, 1998 CL SMOLENICE CASTLE, SLOVAKIA SP NATO ID PHOSPHATE ROCK SYSTEMS; CLINOPTILOLITE; PHOSPHORUS; AMMONIUM; EXCHANGE; MIXTURES; RELEASE AB Natural zeolites have unique physical and chemical properties, which make them attractive for use in slow-release fertilisation for plants, zeoponic plant growth substrates, and soil conditioning and remediation. Zeoponic substrates are defined as artificial soils in which zeolites are a major component. Over the past 10 years, the National Aeronautics and Space Administration (NASA) has been developing a zeoponic substrate for plant growth in space. The primary zeolite used in these substrates is clinoptilolite, because of its selectivity for K+ and NH4+ and its stability in soil-based systems. In addition to NH4- and K-exchanged clinoptilolite, substrates developed by NASA contain either natural or synthetic apatite. Slow-release fertilisation has been achieved in this system by dissolution of either natural or synthetic apatite and cation exchange reactions of clinoptilolite. The synthetic apatites are hydroxyapatites in which Mg, S, and the micronutrients have been substituted into its structure for either Ca and PO4. Hence, these substrates have the capability of supplying all of the essential plant growth nutrients with only the addition of water. In several NASA studies, wheat grown in zeoponic substrates produced greater total dry matter as compared to wheat grown in control substrates watered with nutrient solutions. In another study, however, significantly less wheat grain was produced by plant grown in zeoponic substrates compared to plants grown in control substrates, and this was attributed to reduced seed set caused by the NH4-N source from clinoptilolite exchange. In a subsequent study, the addition of nitrifying bacteria and dolomite to zeoponic substrates produced higher wheat seed yields than control substrates, suggesting that the nitrifying bacteria converted NH4-N to NO3-N, which is more likely to enhance seed set. In a recent plant-growth chamber study, wheat seed production from plant grown in a hydroponic system slightly out performed a zeoponics system; however, the seed production from plants grown in the zeoponics substrate was equivalent to approximately 200 bushels/acre, substantially higher than yields obtained in the field. Wheat and brassica have been grown in zeoponic substrates on the U.S.A. Space Shuttle. During an 8-day flight the growth and development of both plant species on orbit appeared normal and similar to those of plants grown in ground controls. Zeoponic substrates may be used for long-term, plant growth experiments on the International Space Station. Several companies in the United States are marketing zeoponic or zeolite-based products, primarily for the golf industry. One company has developed a zeoponic substrate called "Zeopro(TM)", which is being used as a slow-release fertiliser on golf greens. Because of the recent progress made in the development of zeoponic substrates, we anticipate that the application of zeoponic substrates in the horticultural, agricultural, and turfgrass industries will significantly increase over the next few years. it is likely that these products will be used to improve fertiliser-use efficiency and in environmental protection. With continued sound scientific research, it is likely that zeolites will be: used extensively in the plant growth industry during the first part of 21(st) century. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Ming, DW (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SN2, Houston, TX 77058 USA. NR 31 TC 3 Z9 3 U1 1 U2 3 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0168-132X BN 0-7923-5888-0 J9 NATO ADV SCI I E-APP PY 1999 VL 362 BP 157 EP 176 PG 20 WC Chemistry, Analytical; Chemistry, Physical; Environmental Sciences; Materials Science, Multidisciplinary; Mineralogy SC Chemistry; Environmental Sciences & Ecology; Materials Science; Mineralogy GA BP45S UT WOS:000085199600011 ER PT S AU Andrews, RJ AF Andrews, RJ BE Trembly, B Slikker, W TI Neuroprotective "agents" in surgery - Secret "agent" man, or common "agent" machine? SO NEUROPROTECTIVE AGENTS: FOURTH INTERNATIONAL CONFERENCE SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article; Proceedings Paper CT 4th International Conference on Neuroprotective Agents - Clinical and Experimental Aspects CY NOV 15-19, 1998 CL ANNAPOLIS, MARYLAND SP US FDA, Natl Ctr Toxicol Res, Dept Vet Affairs Med Ctr ID CORONARY-ARTERY BYPASS; COMPLICATIONS; STROKE; IDENTIFICATION; ANGIOPLASTY; PROGRESS; OUTCOMES; TRIALS; BIOPSY AB The search for clinically-effective neuroprotective agents has received enormous support in recent years-an estimated $200 million by pharmaceutical companies on clinical trials for traumatic brain injury alone, At the same time, the pathophysiology of brain injury has proved increasingly complex, rendering the likelihood of a single agent "magic bullet" even more remote. On the other hand, great progress continues with technology that makes surgery less invasive and less risky. One example is the application of endovascular techniques to treat coronary artery stenosis, where both the invasiveness of sternotomy and the significant neurological complication rate (due to microemboli showering the cerebral vasculature) can be eliminated. In this paper we review aspects of intraoperative neuroprotection both present and future. Explanations for the slow progress on pharmacologic neuroprotection during surgery are presented, Examples of technical advances that have had great impact on neuroprotection during surgery are given both from coronary artery stenosis surgery and from surgery for Parkinson's disease. To date, the progress in neuroprotection resulting from such technical advances is an order of magnitude greater than that resulting from pharmacologic agents used during surgery. The progress over the last 20 years in guidance during surgery (CT and MRT image-guidance) and in surgical access (endoscopic and endovascular techniques) will soon be complemented by advances in our ability to evaluate biological tissue intraoperatively in real-time. As an example of such technology, the NASA Smart Probe project is considered. In the long run (i.e., in 10 years or more), pharmacologic "agents" aimed at the complex pathophysiology of nervous system injury in man-will be-the key to true intraoperative neuroprotection. In the near term, however, it is more likely that mundane "agents" based on computers, microsensors, and microeffectors will be the major impetus to improved intraoperative neuroprotection. C1 Texas Tech Univ, Div Neurosurg, Hlth Sci Ctr, El Paso, TX 79905 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Andrews, RJ (reprint author), Texas Tech Univ, Div Neurosurg, Hlth Sci Ctr, 4800 Alberta Ave, El Paso, TX 79905 USA. NR 30 TC 5 Z9 5 U1 0 U2 1 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-222-3 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1999 VL 890 BP 59 EP 72 DI 10.1111/j.1749-6632.1999.tb07981.x PG 14 WC Biochemistry & Molecular Biology; Multidisciplinary Sciences; Clinical Neurology; Pharmacology & Pharmacy SC Biochemistry & Molecular Biology; Science & Technology - Other Topics; Neurosciences & Neurology; Pharmacology & Pharmacy GA BP50F UT WOS:000085330700006 PM 10668414 ER PT J AU Miyoshi, K AF Miyoshi, K TI Diamondlike carbon films: Tribological properties and practical applications SO NEW DIAMOND AND FRONTIER CARBON TECHNOLOGY LA English DT Article DE DLC; tribology; applications; environment; hydrogen; temperature AB The self-lubricating and wear-resistant properties of diamondlike carbon (DLC) films and their applications are reviewed. DLC films, both amorphous, nonhydrogenated DLC (a-DLC) and amorphous, hydrogenated DLC (H-DLC), are examined in contact with chemical-vapor-deposited (CVD) diamond, silicon nitride, or 440C stainless steel in ultrahigh vacuum, dry nitrogen, humid air, and water. The effects of environment and temperature and the role of hydrogen in tribological response with respect to the coefficient of friction and the wear-rate are discussed. Although actual tribological applications of DLC films are already well established for many products, DLC is not a cure-all. However, there is continually growing interest and challenge in commercializing DLC for a wide variety of tribological applications. Actual and potential tribological applications of DLC films are addressed. C1 NASA, John H Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP NASA, John H Glenn Res Ctr Lewis Field, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 25 TC 5 Z9 5 U1 0 U2 0 PU MYU, SCIENTIFIC PUBLISHING DIVISION PI TOKYO PA 1-23-3-303 SENDAGI, TOKYO, 113-0022, JAPAN SN 1344-9931 J9 NEW DIAM FRONT C TEC JI New Diam. Front. Carbon Technol. PY 1999 VL 9 IS 6 BP 381 EP 394 PG 14 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA 307EW UT WOS:000086641200002 ER PT J AU Miyoshi, K AF Miyoshi, K TI Special issue on environmental durability of diamondlike and diamond films and coatings - Preface SO NEW DIAMOND AND FRONTIER CARBON TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr Lewis Field, Washington, DC 20546 USA. RP Miyoshi, K (reprint author), NASA, Glenn Res Ctr Lewis Field, Washington, DC 20546 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU MYU K K PI TOKYO PA SCIENTIFIC PUBLISHING DIV, 2-32-3 SENDAGI, BUNKYO-KU, TOKYO, 113, JAPAN SN 1344-9931 J9 NEW DIAM FRONT C TEC JI New Diam. Front. Carbon Technol. PY 1999 VL 9 IS 6 BP U3 EP U5 PG 3 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA 307EW UT WOS:000086641200001 ER PT B AU Elitzur, M AF Elitzur, M BE Taylor, AR Landecker, TL Joncas, G TI OH 1720 MHz masers - the best indicators of C-shocks and maser saturation SO NEW PERSPECTIVES ON THE INTERSTELLAR MEDIUM SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on New Perspectives on the Interstellar Medium CY AUG 22-28, 1998 CL NARAMATA, CANADA SP Astron Soc Pacific ID SUPERNOVA-REMNANTS; EMISSION; W28 AB Recent observations uncovered a new family of masers: OH 1720 MHz emission from the shocked region where a supernova remnant strikes a molecular cloud. The presence of this maser implies moderate temperatures (50 - 125 K) and densities (similar to 10(5) cm(-3)), and OK column densities of order 10(16) cm(-2). These conditions can exist only if the shocks are of C-type. J-shocks fail by such a wide margin that this maser could become the most powerful indicator of C-shocks. Circular polarization profiles of these masers provide the first direct evidence for maser saturation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Elitzur, M (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 11 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 1-886733-89-9 J9 ASTR SOC P PY 1999 VL 168 BP 201 EP 204 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN45C UT WOS:000081943300026 ER PT S AU Snowden, SL AF Snowden, SL BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI 10(6)-10(7) K gas in the Magellanic Clouds SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID ROSAT; SKY AB The Large Magellanic Cloud contains an extensive distribution of hot plasma and is one of the brightest extragalactic regions in the diffuse 0.5 - 2.0 keV X-ray sky. The plasma is not isothermal but increases in color temperature from west to east from similar to10(6.6) K to similar to10(6.9) K. The total flux from this plasma is similar to 10(38) ergs s(-1). The average emission measure is similar to 0.014 cm(-6) pc, which if the emitting plasma is distributed uniformly throughout the LMC, implies a space density of n(e) similar to 0.002 cm(-3). There is an apparent 1/4 keV enhancement in the southwest of the LMC, which if associated with the LMC implies a considerable emission measure of - 106 K plasma. (The foreground column density of Galactic neutral hydrogen is similar to 6 x 10(2) cm(-2), or several optical depths for 1/4 keV emission.) The Small Magellanic Cloud exhibits less diffuse X-ray emission in the 0.5 - 2.0 keV band than the LMC with a total flux of similar to 4 x 10(36) ergs s(-1). The average emission measure of similar to 0.006 cm(-6) pc also implies a space density of n(e) similar to 0.002 cm(-3). The optical depth of Galactic HI for 1/4 keV X-rays from the SMC is considerably lower than that for the LMC. However, while there is a significant variation in the 1/4 keV band intensity over the SMC field, it is in general not particularly well correlated with anything associated with the SMC, although there is an enhancement which may be related to the leading edge of the SMC. Considerably more work is needed to unravel the origin of the structure, which may be associated instead with either emission or absorption variations in either the disk or halo of the Milky Way. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Snowden, SL (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 32 EP 36 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600006 ER PT S AU Petre, R AF Petre, R BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI Supernova remnants in the Magellanic Clouds SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID OB-ASSOCIATIONS; ABUNDANCES AB Over the past decade, substantial progress has been made in understanding the properties of Magellanic Cloud supernova remnants and their role in the ISM. Among the notable results are the "typing" of progenitors via the X-ray spectra of their remnants, the use of X-ray spectra to measure ISM abundances, and the discovery of remnants with unique properties. I summarize recent studies of MC SNRs, and describe how a refined understanding of the SNR population requires consideration of the unique attributes of each remnant. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Petre, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 74 EP 77 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600013 ER PT S AU Stanimirovic, S Staveley-Smith, L Sault, RJ Dickey, JM Snowden, SL AF Stanimirovic, S Staveley-Smith, L Sault, RJ Dickey, JM Snowden, SL BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI Fractal structure in the interstellar medium of the small Magellanic Cloud? SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID GALACTIC NEUTRAL HYDROGEN; POWER SPECTRUM; EMISSION AB We use the spatial power spectrum for a statistical study of HI in the SMC in order to probe the intrinsic topology of the ISM. A remarkable power-law fit to the spatial power spectrum was found, supporting an alternative ISM model having a fractal nature resulting from interstellar turbulence. C1 Univ Western Sydney Nepean, Kingswood, NSW 2747, Australia. CSIRO, Australia Telescope Natl Facil, Epping, NSW 2121, Australia. Univ Minnesota, Minneapolis, MN 55455 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stanimirovic, S (reprint author), Univ Western Sydney Nepean, POB 10, Kingswood, NSW 2747, Australia. RI Staveley-Smith, Lister/A-1683-2011; Dickey, John/C-6156-2013 OI Staveley-Smith, Lister/0000-0002-8057-0294; NR 4 TC 0 Z9 0 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 103 EP 105 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600020 ER PT S AU Sonneborn, G Pun, CSJ Garnavich, P Kirshner, R AF Sonneborn, G Pun, CSJ Garnavich, P Kirshner, R BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI Birth of supernova remnant 1987A SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID EMISSION AB Recent observations of SN 1987A made with HST/STIS show that the shock interaction of supernova debris with the innermost edge of the circumstellar ring has begun. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02139 USA. RP Sonneborn, G (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 136 EP 138 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600036 ER PT S AU Hwang, U Petre, R Gotthelf, E Hughes, J Keohane, J AF Hwang, U Petre, R Gotthelf, E Hughes, J Keohane, J BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI X-ray spectroscopy of the supernova remnant N103B SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID LARGE MAGELLANIC CLOUD; NOVA REMNANTS AB We report and interpret a new, 100 ks X-ray observation of the supernova remnant N103B obtained by the ASCA Observatory. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. RP Hwang, U (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 141 EP 142 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600038 ER PT S AU Points, S Chu, YH Kim, S Gruendl, R Smith, RC Snowden, S Brandner, W AF Points, S Chu, YH Kim, S Gruendl, R Smith, RC Snowden, S Brandner, W BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI The kinematic structure of the supergiant shell LMC 2 SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID LARGE MAGELLANIC CLOUD C1 Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. JPL, IPAC, Pasadena, CA 91125 USA. RP Points, S (reprint author), Univ Illinois, Dept Astron, 1002 W Green St, Urbana, IL 61801 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 156 EP 157 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600045 ER PT S AU Zinnecker, H Brandl, B Brandner, W Moneti, A Hunter, D AF Zinnecker, H Brandl, B Brandner, W Moneti, A Hunter, D BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI 30 Doradus: The low-mass stars SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID STARBURST; GALAXIES AB We present a first analysis of our deep NICMOS/HST F160W images of the 30 Doradus cluster, aimed at detecting the low-mass stellar population (M less than or equal to 2 MD). We find that the infrared luminosity function keeps rising towards the faint end and that there is no indication of a low-mass IMF cut-off down to at least 1.5 M.. We also find a change of slope (steepening) in the luminosity function as a function of radial distance from the cluster center. The faintest stars we have detected have H=22.5 mag, corresponding to about M = 0.4 M. at an age of 2 Myr. C1 Inst Astrophys, D-14482 Potsdam, Germany. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, IPAC, Pasadena, CA 91109 USA. VILSPA, ISO Sci Operat Ctr, Madrid 28080, Spain. Lowell Observ, Flagstaff, AZ 86001 USA. RP Zinnecker, H (reprint author), Inst Astrophys, Sternwarte 16, D-14482 Potsdam, Germany. NR 10 TC 1 Z9 1 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 222 EP 226 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600059 ER PT S AU Parker, JW Hill, JK Cornett, R Hollis, J Zamkoff, E Bohlin, RC O'Connell, RW Neff, SG Smith, AM Stecher, TP Roberts, MS AF Parker, JW Hill, JK Cornett, R Hollis, J Zamkoff, E Bohlin, RC O'Connell, RW Neff, SG Smith, AM Stecher, TP Roberts, MS BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI Ultraviolet Imaging Telescope observations of the Magellanic Clouds SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID STELLAR ASSOCIATIONS; UIT; PHOTOMETRY; 30-DORADUS AB We present an analysis of wide-field, far-ultraviolet images of the LMC and SMC obtained by the Ultraviolet Imaging Telescope. The photometric catalog of over 37,000 stars allows us to make large-scale, statistical studies of massive star formation in OB associations and in the field population. Our results show that: (1) the most probable slope for the initial mass function (IMF) of field stars is Gamma = -1.80, slightly steeper than the Salpeter slope; and (2) there doesn't seem to be a single, unique IMF slope for stars in OB associations, with a range of values from Gamma = -1.0 to -2.0. We also analyze the stellar vs. diffuse UV flux, and the population of OB star candidates in the field. C1 SW Res Inst, Boulder, CO 80302 USA. NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Greenbelt, MD 20771 USA. STScI, Baltimore, MD 21218 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. RP Parker, JW (reprint author), SW Res Inst, Boulder, CO 80302 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 237 EP 238 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600062 ER PT S AU Welty, DE Frisch, PC Hobbs, LM York, DG Blades, JC Lauroesch, JT Sonneborn, G AF Welty, DE Frisch, PC Hobbs, LM York, DG Blades, JC Lauroesch, JT Sonneborn, G BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI Interstellar abundances in the Magellanic Clouds SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID 1987A AB We discuss the relative gas-phase abundances found for the predominantly neutral interstellar clouds - located in the Galactic disk and halo, in the LMC or SMC, and (perhaps) in between - along the lines of sight to Sk 108 in the SMC and to SN 1987A in the LMC. C1 Univ Chicago, Chicago, IL 60637 USA. STScI, Greenbelt, MD 20771 USA. Northwestern Univ, Evanston, IL 60208 USA. Goddard Space Flight Ctr, Baltimore, MD 21218 USA. RP Welty, DE (reprint author), Univ Chicago, 5640 S Ellis Ave, Chicago, IL 60637 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 277 EP 278 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600074 ER PT S AU Sweigart, AV AF Sweigart, AV BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI Radiation-pressure ejection of planetary nebulae in asymptotic-giant-branch stars SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council AB We have investigated the possibility that radiation pressure might trigger planetary nebula (PN) ejection during helium-shell flashes in asymptotic-giant-branch (AGB) stars. We find that the outward flux at the base of the hydrogen envelope during a flash will reach the Eddington limit when the envelope mass M-env falls below a critical value that depends on the core mass M-H and composition. These results may help to explain the helium-burning PN nuclei found in the Magellanic Clouds. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sweigart, AV (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 370 EP 371 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600099 ER PT S AU Vanlandingham, KM Schwarz, GJ Starrfield, S Hauschildt, PH Shore, SN Sonneborn, G AF Vanlandingham, KM Schwarz, GJ Starrfield, S Hauschildt, PH Shore, SN Sonneborn, G BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI Analyses of the LMC novae SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council AB In the past 10 years, 6 classical novae have been observed in the Large Magellanic Cloud (LMC). We have begun a study of these objects using ultraviolet spectra obtained by IUE and optical spectra from nova surveys. We are using the results of this study to further our understanding of novae and stellar evolution. Our study includes analysis of both the early, optically thick spectra using model atmospheres (Hauschildt et al. 1992), and the later nebular spectra using optimization of photoionization codes (Ferland 1996; James & Roos 1993). By analysing all the LMC novae in a consistent manner, we can compare their individual results and use their combined properties to calibrate Galactic novae. In addition, our studies can be used to determine the elemental abundances of the nova ejecta, the amount of mass ejected, and the contribution of novae to the ISM abundances. To date we have analysed Nova LMC 1988#1 (Schwarz et al. 1998) and Nova LMC 1990#1 (Vanlandingham et al. 1999), and have obtained preliminary results for Nova LMC 1991. The results of this work are presented in this poster. C1 Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. Indiana Univ, Dept Phys & Astron, South Bend, IN 46634 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Vanlandingham, KM (reprint author), Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 391 EP 392 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600109 ER PT S AU Grebel, EK Brandner, W AF Grebel, EK Brandner, W BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI Recent star formation history of the Magellanic Clouds SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID LMC AB A new age calibration of Cepheids and supergiants is used to study the large-scale recent star formation history of the LMC and the SMC. We find evidence for migration of star formation along the LMC bar as well as for the existence of long-lived (approximate to 200 Myr) extended star-forming features. C1 Univ Calif Santa Cruz, UCO, Lick Observ, Santa Cruz, CA 95064 USA. JPL, IPAC, Pasadena, CA 91125 USA. RP Grebel, EK (reprint author), Univ Calif Santa Cruz, UCO, Lick Observ, Santa Cruz, CA 95064 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 470 EP 471 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600135 ER PT S AU Li, PS Thronson, HA AF Li, PS Thronson, HA BE Chu, YH Suntzeff, NB Hesser, JE Bohlender, DA TI New particle simulation of the Magellanic Clouds SO NEW VIEWS OF THE MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 190th Symposium of the International-Astronomical-Union CY JUL 12-17, 1998 CL VICTORIA, CANADA SP Int Astron Union, Canadian Inst Theoret Astrophys, Univ Victoria, Dept Phys & Astron, Herzberg Inst Astrophys, Natl Res Council ID STREAM; GALAXY AB We use a modified TreeSPH code to simulate the MilkyWay-LMC-SMC system using the latest observational results from Hipparcos on the proper motion of the Clouds. More than 120,000 particles are used for the simulation. Gravitational and hydrodynamic interactions among gaseous and stellar components in the system have been considered. The Magellanic Stream, some high velocity clouds, and the barred structure of LMC are reproduced. A leading gas arm from the SMC is predicted. From the simulation, the long term binary status of LMC-SMC is questioned as frequent encounters between the LMC and the SMC will have difficulty in explaining the survival of the SMC. C1 Univ Wyoming, Laramie, WY 82071 USA. NASA, Off Space Sci, Washington, DC 20546 USA. RP Li, PS (reprint author), Univ Wyoming, POB 3905,Univ Stn, Laramie, WY 82071 USA. RI Thronson, Harley/E-3382-2012 NR 4 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-021-8 J9 IAU SYMP PY 1999 IS 190 BP 503 EP 505 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU32Y UT WOS:000175704600142 ER PT B AU Wilkie, WK Belvin, WK Park, KC AF Wilkie, WK Belvin, WK Park, KC BE Hagood, NW Atalla, MJ TI Torsional stiffness optimization of piezoelectric active twist helicopter rotor blades SO NINTH INTERNATIONAL CONFERENCE ON ADAPTIVE STRUCTURES AND TECHNOLOGIES LA English DT Proceedings Paper CT 9th International Conference on Adaptive Structures and Technologies CY OCT 14-16, 1998 CL BOSTON, MA SP MIT, Act Mat & Struct Lab, USAF, Off Sci Res ID FIBER COMPOSITES AB Results from an analytical effort to examine several aeroelastic performance trade-offs inherent in the design of piezoelectric active twist helicopter rotor blades are given. The development of a hovering flight eigenanalysis suitable for efficient design optimization studies of active twist rotor blades is described. This eigenvalue analysis, together with a suitable aeroelastic performance index, is used to optimize the torsional stiffness of a conceptual full-scale active fiber composite helicopter rotor blade. The hovering flight optimized blade design is then examined under forward flight dynamic stall conditions using a nonlinear, time-domain numerical aeroelasticity simulation. Forward flight dynamic stall vibratory load trends for the optimized active twist blade are compared to results for a non-optimized baseline active twist rotor design, and with those for a conventional, passive structure, helicopter blade. It is shown that increasing the torsional stiffness of the baseline active twist design, depite reducing overall twist actuation authority, improves overall active and passive dynamic stall performance qualities. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Wilkie, WK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. RI park, k.c./E-8898-2010 NR 14 TC 0 Z9 0 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-755-5 PY 1999 BP 213 EP 224 PG 12 WC Automation & Control Systems; Instruments & Instrumentation; Materials Science, Multidisciplinary; Mechanics SC Automation & Control Systems; Instruments & Instrumentation; Materials Science; Mechanics GA BP99T UT WOS:000086846600021 ER PT S AU Generazio, ER AF Generazio, ER BE Green, RE TI Overview of the National Aeronautics and Space Administration's Nondestructive Evaluation (NDE) Program SO NONDESTRUCTIVE CHARACTERIZATION OF MATERIALS IX SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Symposium on Nondestructive Characterization of Materials CY JUN 28-JUL 02, 1999 CL SYDNEY, AUSTRALIA SP Amer Soc Nondestruct Testing, NASA, Langley Res Ctr, Natl Sci Fdn, USN, Off Res, USA, Res Off Far E, USAF, Asian Off Aerosp R&D, USN, Off Res Int Field Off Asia AB NASA's Office of Safety and Mission Assurance sponsors an Agency-wide NDE Program that supports Aeronautics and Space Transportation Technology, Human Exploration and Development of Space, Earth Science, and Space Science Enterprises. For each of these Enterprises, safety is the number one priority. Development of the next generation aero-space launch and transportation vehicles, satellites, and deep space probes have highlighted the enabling role that NDE plays in these advanced technology systems. Specific areas of advanced component development component integrity, and structural heath management are critically supported by NDE technologies. The simultaneous goals of assuring safety, maintaining overall operational efficiency, and developing and utilizing revolutionary technologies to expand human activity and space-based commerce in the frontiers of air and space places increasing demands on the Agencies NDE infrastructure and resources. Tn this presentation, an overview of NASA's NDE Program will be presented, that includes a background and status of current Enterprise NDE issues, and the NDE investment areas being developed to meet Enterprise safety and mission assurance needs through the year 2009 and beyond. C1 NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23665 USA. RP Generazio, ER (reprint author), NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23665 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 1-56396-911-4 J9 AIP CONF PROC PY 1999 VL 497 BP 251 EP 256 PG 6 WC Materials Science, Characterization & Testing; Physics, Applied SC Materials Science; Physics GA BP29Z UT WOS:000084618600037 ER PT S AU Bar-Cohen, Y Mal, A Lih, SS Chang, ZS AF Bar-Cohen, Y Mal, A Lih, SS Chang, ZS BE Mal, AK TI Composite materials stiffness determination and defects characterization using enhanced leaky Lamb wave dispersion data acquisition method SO NONDESTRUCTIVE EVALUATION OF AGING AIRCRAFT, AIRPORTS, AND AEROSPACE HARDWARE III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware III CY MAR 03-05, 1999 CL NEWPORT BEACH, CA SP Soc Photo Opt Instrumentat Engineers, Soc Rxptl Mech Inc, Amer Soc Nondestruct Testing, Japanese Soc Nondestruct Inspect DE leaky Lamb waves (LLW); NDE; composites; stiffness constants; aging aircraft AB The leaky Lamb wave (LLW) technique is approaching a maturity level that is making it an attractive quantitative NDE tool for composites and bonded joints. Since it was first observed in 1982, the phenomenon has been studied extensively, particularly in composite materials. The wave is induced by oblique insonification using a pitch-catch arrangement and the plate wave modes are detected by identifying minima in the reflected spectra to obtain the dispersion data. The wave behavior in multi-orientation laminates has been well documented and corroborated experimentally with high accuracy. The sensitivity of the wave to the elastic constants of the material and to the boundary conditions led to the capability to measure the elastic properties of bonded joints. Recently, the authors significantly enhanced the LLW method's capability by increasing the speed of the data acquisition, the number of modes that can be identified and the accuracy of the data inversion. In spite of the theoretical and experimental progress, methods that employ oblique insonification of composites are still not being applied as standard industrial NDE methods, The authors investigated the issues that are hampering the transition of the LLW to industrial applications and identified 4 key issues. The current capability of the method and the nature of these issues are described in this paper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 82-105, Pasadena, CA 91109 USA. NR 8 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 0-8194-3056-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3586 BP 250 EP 255 DI 10.1117/12.339892 PG 6 WC Engineering, Aerospace; Materials Science, Characterization & Testing; Optics SC Engineering; Materials Science; Optics GA BM82F UT WOS:000079846700026 ER PT S AU Cmar-Mascis, NA Winfree, WP Parker, FR AF Cmar-Mascis, NA Winfree, WP Parker, FR BE Mal, AK TI Advanced radiographic methods for visualization of corrosion in aircraft structures SO NONDESTRUCTIVE EVALUATION OF AGING AIRCRAFT, AIRPORTS, AND AEROSPACE HARDWARE III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware III CY MAR 03-05, 1999 CL NEWPORT BEACH, CA SP Soc Photo Opt Instrumentat Engineers, Soc Rxptl Mech Inc, Amer Soc Nondestruct Testing, Japanese Soc Nondestruct Inspect DE x-ray; radiography; corrosion; aircraft; computed tomography; laminography; NDE ID RAY AB Methods for enhanced detection and characterization of corrosion in aircraft structures are presented. A unique Reverse Geometry X-ray(R) system was utilized for real time radiographic imaging of structures. This system has several possible advantages as compared to conventional radiography. First, the x-ray detector can be miniaturized and easily positioned inside a complex structure (such as an aircraft wing) 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 positions of flaws and enhances separation of features at the surface from features inside the structure. A method is presented for calibration of the eight detectors for reduction of radiographic data to thickness measurements. Results are presented for measurements on a varying thickness sample. Laminographic reconstruction of data from the multiple detector system is presented. Laminographic imaging methods are shown to be capable of separating surface features from corrosion in the lap joint and locating corrosion in multilayer structures. Removal of surface features to enhance definition of corrosion boundaries is discussed. C1 NASA, Langley Res Ctr, USA, Res Lab,Vehicle Technol Ctr, Hampton, VA 23681 USA. RP Cmar-Mascis, NA (reprint author), NASA, Langley Res Ctr, USA, Res Lab,Vehicle Technol Ctr, MS 231, Hampton, VA 23681 USA. NR 8 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 0-8194-3056-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3586 BP 332 EP 341 DI 10.1117/12.339901 PG 10 WC Engineering, Aerospace; Materials Science, Characterization & Testing; Optics SC Engineering; Materials Science; Optics GA BM82F UT WOS:000079846700035 ER PT S AU Bar-Cohen, Y Mal, AK Lasser, M AF Bar-Cohen, Y Mal, AK Lasser, M BE Mal, AK TI NDE of hidden flaws in aging aircraft structures using obliquely backscattered ultrasonic signals (OBUS) SO NONDESTRUCTIVE EVALUATION OF AGING AIRCRAFT, AIRPORTS, AND AEROSPACE HARDWARE III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware III CY MAR 03-05, 1999 CL NEWPORT BEACH, CA SP Soc Photo Opt Instrumentat Engineers, Soc Rxptl Mech Inc, Amer Soc Nondestruct Testing, Japanese Soc Nondestruct Inspect DE ultrasonic backscattering; NDE; aging aircraft; corrosion detection; flaw imaging AB Corrosion is a relatively slow material degradation process to which metallic structures of aircraft are subjected during service and it can appear in many forms. Generally, corrosion protection for preventing or inhibiting the formation and growth of corrosion damage on aircraft structures is wed-established technology. Unfortunately, despite preventive measures, corrosion does occur and its probability of formation significantly increases as structures age. Corrosion detection and characterization at the initiation stages, while hidden under paint or in concealed areas, still poses a challenge to inspection science and technology. Corrosion damage is costly and it carries the risk of loss of life as well as hardware in case of catastrophic failure. The authors are investigating the application of obliquely backscattered ultrasonic signals (OBUS) as a means of detecting and characterizing corrosion under paint in metallic panels. OBUS were measured using oblique insonification and were used to produce C-scan images of corrosion damage located on both top and bottom faces of test panels through the paint. A combination of OBUS data and a sensor-array real-time imaging (SARTI) system is being developed for field applications. SARTI uses Charged Coupled Device (CCD) to display ultrasonic data and the integrated system has the potential to reduce the need for paint stripping prior to inspection. The main features of the combined OBUS and SARTI are described in this paper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 82-105, Pasadena, CA 91109 USA. NR 8 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 0-8194-3056-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3586 BP 347 EP 353 DI 10.1117/12.339903 PG 7 WC Engineering, Aerospace; Materials Science, Characterization & Testing; Optics SC Engineering; Materials Science; Optics GA BM82F UT WOS:000079846700037 ER PT S AU Gyekenyesi, AL Baaklini, GY AF Gyekenyesi, AL Baaklini, GY BE Baaklini, GY Lebowitz, CA Boltz, ES TI Thermoelastic stress analysis: The mean stress effect in metallic alloys SO NONDESTRUCTIVE EVALUATION OF AGING MATERIALS AND COMPOSITES III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Nondestructive Evaluation of Aging Materials and Composites III CY MAR 03-05, 1999 CL NEWPORT BEACH, CA SP Soc Photo Opt Instrumentat Engineers, Soc Exptl Mech Inc, Amer Soc Nondestruct Testing, Japanese Soc Nondestruct Testing DE thermoelastic stress analysis; TSA; thermoelastic constant; residual stress; mean stress; stress pattern analysis by thermal emission; SPATE AB The primary objective of this study involved the utilization of the thermoelastic stress analysis (TSA) method to demonstrate the mean stress dependence of the thermoelastic constant. Titanium and nickel base alloys, commonly employed in aerospace gas turbines, were the materials of interest. The repeatability of the results was studied through a statistical analysis of the data. Although the mean stress dependence was well established, the ability to confidently quantify it was diminished by the experimental variations. If calibration of the thermoelastic response to mean stress can be successfully implemented, it is feasible to use the relationship to determine a structures residual stress state. C1 NASA, Lewis Res Ctr, Cleveland, OH 44115 USA. RP Gyekenyesi, AL (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,MS 6-1, Cleveland, OH 44115 USA. NR 7 TC 3 Z9 3 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 0-8194-3055-2 J9 P SOC PHOTO-OPT INS PY 1999 VL 3585 BP 142 EP 151 DI 10.1117/12.339842 PG 10 WC Materials Science, Characterization & Testing; Optics SC Materials Science; Optics GA BM82E UT WOS:000079846400015 ER PT S AU Cramer, KE Winfree, WP Reid, D Johnson, J AF Cramer, KE Winfree, WP Reid, D Johnson, J BE Reuter, WG TI Thermographic detection and quantitative characterization of corrosion by application of thermal line source SO NONDESTRUCTIVE EVALUATION OF UTILITIES AND PIPELINES III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Nondestructive Evaluation of Utilities and Pipelines III CY MAR 04, 1999 CL NEWPORT BEACH, CA SP Soc Photo Opt Instrumentat Engineers, Soc Exptl Mech Inc, Amer Soc Nondestruct Testing, Japanese Soc Nondestruct Inspect DE infrared; thermal; NDE; corrosion ID AIRCRAFT AB Wall thinning in utility boiler waterwall tubing is a significant inspection concern for boiler operators. Historically, conventional ultrasonics has been used for inspection of these tubes. This technique has proved to be very labor intensive and slow. This has resulted in a "spot check" approach to inspections, making thickness measurements over a relatively small percentage of the total boiler wall area. NASA Langley Research Center has developed a thermal NDE technique designed to image and quantitatively characterize the amount of material thinning present in steel tubing. The technique involves the movement of a thermal line source across the outer surface of the tubing followed by an infrared imager at st fixed distance behind the line source. Quantitative images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal Line source, coupled with this analysis technique, represents a significant improvement in the inspection speed for large structures such as boiler waterwalls while still providing high-resolution thickness measurements. A theoretical basis for the technique will be presented thus demonstrating the quantitative nature of the technique. Further, results of laboratory experiments on flat panel specimens with fabricated material loss regions will be presented to demonstrate the capabilities of the technique. Additionally, the results of applying this technology to actual waterwall tubing samples will be presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cramer, KE (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 6 TC 2 Z9 2 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 0-8194-3058-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3588 BP 29 EP 38 DI 10.1117/12.339947 PG 10 WC Materials Science, Characterization & Testing; Optics SC Materials Science; Optics GA BM81Z UT WOS:000079833500004 ER PT S AU Watson, MD Jayroe, RR AF Watson, MD Jayroe, RR BE Winston, R TI Fresnel lens solar concentrator design based on geometric optics and blackbody radiation equation SO NONIMAGING OPTICS: MAXIMUM EFFICIENCY LIGHT TRANSFER V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 5th Conference on Nonimaging Optics - Maximum Efficiency Light Transfer CY JUL 21-22, 1999 CL DENVER, CO SP SPIE DE solar concentration; geometrical optics; blackbody; circle of least confusion; flux AB Fresnel lenses have been used for years as solar concentrators in a variety of applications. Several variables effect the final design of these lenses including: lens diameter, image spot distance from the lens, and bandwidth focused in the image spot. Defining the image spot as the geometrical optics circle of least confusion, a set of design equations has been derived to define the groove angles for each groove on the lens. These equations allow the distribution of light by wavelength within the image spot to be calculated. Combining these equations with the blackbody radiation equations power, power distribution, and flux within the image spot can be calculated. In addition, equations have been derived to design a lens to produce maximum flux in a given spot size. Using these equations, a lens may be designed to optimize the spot energy concentration for given energy source. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Watson, MD (reprint author), NASA, George C Marshall Space Flight Ctr, MS SD72,MSFC, Huntsville, AL 35812 USA. NR 4 TC 3 Z9 3 U1 2 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 0-8194-3267-9 J9 P SOC PHOTO-OPT INS PY 1999 VL 3781 BP 85 EP 93 DI 10.1117/12.368239 PG 9 WC Optics SC Optics GA BN97Y UT WOS:000083741800010 ER PT J AU Lu, P Burken, JJ AF Lu, P Burken, JJ TI Controlling aircraft with engine thrust only: nonlinear challenges SO NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS LA English DT Article DE nonlinear control; flight control; nonlinear dynamics ID PREDICTIVE CONTROL; SYSTEMS; DESIGN C1 Iowa State Univ, Dept Aerosp Engn & Engn Mech, Ames, IA 50011 USA. NASA, Dryden Flight Res Ctr, Edwards, CA 93523 USA. RP Lu, P (reprint author), Iowa State Univ, Dept Aerosp Engn & Engn Mech, Ames, IA 50011 USA. NR 17 TC 1 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0362-546X J9 NONLINEAR ANAL-THEOR JI Nonlinear Anal.-Theory Methods Appl. PD JAN PY 1999 VL 35 IS 1 BP 21 EP 35 PG 15 WC Mathematics, Applied; Mathematics SC Mathematics GA 114RH UT WOS:000075622300002 ER PT S AU Goldstein, ML Ghosh, S Siergar, E Jayanti, V AF Goldstein, ML Ghosh, S Siergar, E Jayanti, V BE Passot, T Sulem, PL TI Modeling the dissipation range of magnetofluid turbulence SO NONLINEAR MHD WAVES AND TURBULENCE SE LECTURE NOTES IN PHYSICS LA English DT Proceedings Paper CT Workshop on Nonlinear MHD Waves and Turbulence CY DEC 01-04, 1998 CL NICE, FRANCE SP CRNS ID INTERPLANETARY ALFVENIC FLUCTUATIONS; SOLAR-WIND; MAGNETOHYDRODYNAMIC TURBULENCE; VOYAGER OBSERVATIONS; MAGNETIC-FIELD; MHD TURBULENCE; EVOLUTION; DYNAMICS; INSTABILITY; TEMPERATURE AB Fluid descriptions of plasma phenomena are valuable tools for simulating large-scale phenomena. Fluid simulations, however, generally use idealized models to describe the dissipation of energy at small scales. The physical dissipation scale is usually considerably smaller than what can be evaluated numerically when using fluid descriptions of macroscopic phenomena. Here we review several approaches for describing dissipation in magnetofluid turbulence. These simulations divide into two general classes: those that employ mathematical models of the dissipation to concentrate dissipation to regions of large gradients in the fluid parameters, and those that use generalizations of Ohm's law to model kinetic effects more completely described by the Vlasov-Maxwell equations. The former class includes using either hyperresistivity and hyperviscosity or nonlinear dissipation operators to locate dissipation in regions of strong gradients. These terms replace the standard Navier-Stokes dissipation term in the magnetohydrodynamic (MHD) equations. The second class of models includes one that modifies the magnetofluid equations by including the Hall and Finite Larmor radius corrections to Ohm's Law and another approach that uses a coarse-grained fluid description to describe the effect of the ion cyclotron instability on the elements of the pressure tensor. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Goldstein, ML (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Goldstein, Melvyn/B-1724-2008 NR 62 TC 5 Z9 5 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0075-8450 BN 3-540-66697-4 J9 LECT NOTES PHYS PY 1999 VL 536 BP 269 EP 290 PG 22 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Mathematics, Applied; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Geochemistry & Geophysics; Mathematics; Physics GA BR08P UT WOS:000165612700011 ER PT J AU Swank, JH AF Swank, JH TI The Rossi X-ray Timing Explorer SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID RXTE OBSERVATIONS; GRS-1915+105; STAR 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. RI Swank, Jean/F-2693-2012 NR 44 TC 22 Z9 22 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 12 EP 19 DI 10.1016/S0920-5632(98)00175-3 PG 8 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800003 ER PT J 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 TI Rossi-XTE long-term monitoring of Eta Carinae SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 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. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. CNR, Ist Astrofis Spaziale, Area Ric Tor Vergata, I-00133 Rome, Italy. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. RP Corcoran, MF (reprint author), NASA, Goddard Space Flight Ctr, Code 660-2, Greenbelt, MD 20771 USA. RI Swank, Jean/F-2693-2012 NR 4 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 33 EP 35 DI 10.1016/S0920-5632(98)00178-9 PG 3 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800006 ER PT J AU Viotti, R Corcoran, MF Damineli, A Grandi, P AF Viotti, R Corcoran, MF Damineli, A Grandi, P TI BeppoSAX observations of Eta Carinae: A multicolour study of its recent low and high states SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID RADIO OUTBURST; VARIABILITY AB We report on a ongoing campaign of multiwavelength observations of the superluminous galactic object eta Carinae, following its mid 1992 low state. The BeppoSAX LEGS and MECS observations of December 1996 detected many sources in the eta Car field, eta Car itself is by far the brightest, with a multi-component spectrum. The object was in a high state in agreement with ASCA and RossiXTE observations. Optical (LNA), ultraviolet (IUE), and radio observations indicate a general flux modulation following the 5.52 y cycle. A gradual decrease of these fluxes since 1995 are suggestive of the approaching of the next low state. C1 CNR, Ist Astrofis Spaziale, Area Ric Roma Tor Vergata, I-00133 Rome, Italy. USRA, Columbia, MD 21045 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Boulder, CO 80309 USA. IAGUSP, Sao Paulo, Brazil. RP Viotti, R (reprint author), CNR, Ist Astrofis Spaziale, Area Ric Roma Tor Vergata, I-00133 Rome, Italy. RI Damineli, Augusto/D-8210-2012; OI Damineli, Augusto/0000-0002-7978-2994; Grandi, Paola/0000-0003-1848-6013 NR 16 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 36 EP 39 DI 10.1016/S0920-5632(98)00179-0 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800007 ER PT J AU Rothschild, RE Lingenfelter, RE Blanco, PR Gruber, DE Heindl, WA MacDonald, D Marsden, DF Pelling, MR Jahoda, K Allen, GE Swank, JH Woosley, SE Nomoto, K Higdon, C AF Rothschild, RE Lingenfelter, RE Blanco, PR Gruber, DE Heindl, WA MacDonald, D Marsden, DF Pelling, MR Jahoda, K Allen, GE Swank, JH Woosley, SE Nomoto, K Higdon, C TI RXTE observations of Cas A SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID CASSIOPEIA-A; TI-44 AB Rossi X-ray Timing Explorer (RXTE) observations of the bright supernova remnant Cas A have revealed a hard power law component above 10 keV in addition to two thermal components inferred from ASCA measurements of the many line centroids from low-Z elements. The power law can be shown to be consistent with synchrotron emission from radio to hard x-rays by electrons of up to 4x10(13) eV. Measurement of the 1157 keV line by CGRO from Sc-44 in the chain of decay of Ti-44 predicts that the two Ti-44 lines at 68 and 78 keV should appear at the CGRO intensity. RXTE has placed upper limits on such lines that are marginally consistent with the CGRO measurement. Implications of these results on sites for cosmic ray acceleration and nucleosynthesis are discussed. C1 Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Tokyo, Sch Sci, Dept Astron, Bunkyo Ku, Tokyo 113, Japan. Claremont Coll, Joint Sci Ctr, Claremont, CA 91711 USA. RP Rothschild, RE (reprint author), Univ Calif San Diego, Ctr Astrophys & Space Sci, 9500 Gilman Dr, La Jolla, CA 92093 USA. RI Nomoto, Ken'ichi/A-4393-2011; Jahoda, Keith/D-5616-2012; Swank, Jean/F-2693-2012 NR 10 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 68 EP 73 DI 10.1016/S0920-5632(98)00186-8 PG 6 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800014 ER PT J AU Strohmayer, TE Swank, JH Zhang, W AF Strohmayer, TE Swank, JH Zhang, W TI The periods discovered by RXTE in thermonuclear flash bursts SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID X-RAY-BURSTS; NEUTRON-STARS; BINARY; PULSARS 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. RI Swank, Jean/F-2693-2012 NR 14 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 129 EP 134 DI 10.1016/S0920-5632(98)00195-9 PG 6 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800023 ER PT J AU Israel, GL Angelini, L Burderi, L Campana, S Dal Fiume, D Frontera, F Mereghetti, S Orlandini, M van Paradijs, J Parmar, AN Piraino, S Ricci, D Santangelo, A Stella, L Vietri, M White, NE AF Israel, GL Angelini, L Burderi, L Campana, S Dal Fiume, D Frontera, F Mereghetti, S Orlandini, M van Paradijs, J Parmar, AN Piraino, S Ricci, D Santangelo, A Stella, L Vietri, M White, NE TI SAX and XTE observations of GX 1+4, SMCX-1, RX J0146.9+6121 and 4U 0142+614, a sample of X-ray pulsators with extreme properties SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID PULSARS AB We report and discuss preliminary results obtained from the analysis of a sample of X-ray pulsars observed by SAX and XTE. The sample includes GX1+4, a similar to 125 s period low-mass X-ray pulsar which shows extreme properties and spin-up/down behaviour; 4U 0142+614, a member of the recently identified class of "Anomalous" X-ray pulsars, SMC X-1, a short period (similar to 0.71 s) X-ray pulsar in a high-mass binary, and RX J0146.9+6121, the slowest spinning accreting neutron star currently known (similar to 25 min period). C1 ICRA, Osservatorio Astron Roma, I-00040 Monte Porzio Catone, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Penn, Philadelphia, PA 19104 USA. Univ Amsterdam, UAH, NL-1012 WX Amsterdam, Netherlands. ESA, ESTEC, F-75738 Paris 15, France. RP Israel, GL (reprint author), ICRA, Osservatorio Astron Roma, Via Osservatorio 2, I-00040 Monte Porzio Catone, Italy. RI White, Nicholas/B-6428-2012; Orlandini, Mauro/H-3114-2014; OI Israel, GianLuca/0000-0001-5480-6438; White, Nicholas/0000-0003-3853-3462; Orlandini, Mauro/0000-0003-0946-3151; Piraino, Santina/0000-0003-0122-6899; Burderi, Luciano/0000-0001-5458-891X; Campana, Sergio/0000-0001-6278-1576; Parmar, Arvind/0000-0002-3307-6517; MEREGHETTI, SANDRO/0000-0003-3259-7801 NR 5 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 141 EP 144 DI 10.1016/S0920-5632(98)00197-2 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800025 ER PT J 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 TI Peak luminosities of bursts from GRO J1744-28 measured with the RXTE PCA; Italia: wij post 17 two 4s - a one man marching band - got darn bright. SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID RAY TIMING EXPLORER; COUNTER ARRAY EXPERIMENT; PERFORMANCE 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. MIT, Ctr Space Res, Cambridge, MA 02138 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 10 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 210 EP 215 DI 10.1016/S0920-5632(98)00210-2 PG 6 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800038 ER PT J AU Heindl, W Blanco, P Gruber, D Pelling, M Rothschild, R Jahoda, K AF Heindl, W Blanco, P Gruber, D Pelling, M Rothschild, R Jahoda, K TI A search for cyclotron lines in the bursting pulsar, GRO J1744-28 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY AB We report a search for cyclotron line absorption in the pulsed spectrum of the "Bursting Pulsar", GRO J1744-28 using the Proportional Counter Array (PCA) and the High Energy X-ray Timing Experiment (HEXTE) on the Rossi X-ray Timing Explorer (RXTE). We focus on data obtained around the peak of the 1996-1997 outburst. Improvements made in these analyses include the use of more accurate PCA and HEXTE detector response matrices, data with a larger overlapping energy band, and a continuum model especially well suited to cyclotron line searches. We find that the spectrum can be adequately fit with a smooth continuum model typical of other X-ray pulsars, with no modification for cyclotron absorption required. In fact, the data are inconsistent with cyclotron features with depths greater than a few percent of the continuum. C1 Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Heindl, W (reprint author), Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. RI Jahoda, Keith/D-5616-2012 NR 13 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 216 EP 219 DI 10.1016/S0920-5632(98)00211-4 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800039 ER PT J AU Zand, JJMI Strohmayer, TE Baykal, A AF Zand, JJMI Strohmayer, TE Baykal, A TI Spin down and oscillations in 4U 1907+09: a retrograde disk? SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID QUASI-PERIODIC OSCILLATIONS; RAY; PULSAR AB X-ray observations of the accretion-powered X-ray pulsar 4U 1907+09, obtained during February 1996 with the Proportional Counter Array on the Rossi X-ray Timing Experiment (RXTE), have shown interesting features of which three are: 1) a flare occurred lasting at least a few hours and close to the time of apastron; 2) the spin down rate, when measured since the pulsar discovery in 1983, is within 8% equal to a value of (P)over dot(pulse) = +0.225 s yr(-1), this suggest that the pulsar is in a monotonous spin down mode; 3) transient similar to 18 s oscillations appeared during the flare. The oscillations may be interpreted as Keplerian motion of an accretion disk near the magnetospheric radius. This, and the notion that the co-rotation radius is much larger than any conceivable value for the magnetospheric radius (because of the long spin period), renders it unlikely that this pulsar spins near equilibrium like is suspected for other slowing accreting X-ray pulsars. We suggest as an alternative that perhaps the frequent occurrence of a retrograde transient accretion disk may be consistently slowing the pulsar down. Further observations of flares can provide more evidence of this. C1 SRON, NL-3584 CA Utrecht, Netherlands. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Middle E Tech Univ, Dept Phys, TR-06531 Ankara, Turkey. RP Zand, JJMI (reprint author), SRON, Sorbonnelaan 2, NL-3584 CA Utrecht, Netherlands. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 224 EP 227 DI 10.1016/S0920-5632(98)00213-8 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800041 ER PT J AU Boirin, L Olive, JF Barret, D Grindlay, JE Swank, JH Smale, AP AF Boirin, L Olive, JF Barret, D Grindlay, JE Swank, JH Smale, AP TI RXTE/PCA observation of the X-ray burster 1E1724-3045 - Aperiodic variability of the persistent emission SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY AB We report on the November 1996 Rossi X-ray Timing Explorer (RXTE) observation of the X-ray burster 1E1724-3045 with the Proportional Counter Array (PCA). The persistent X-ray emission shows a high level of noise variability, the so-called High Frequency Noise (HFN), with a fractional Root heart Squared (RMS) of similar to 25% in the 2 x 10(-3) - 40 Hz range (2-20 keV). The Fourier Power Density Spectrum (PDS) can be modeled in terms of the sum of two "shot noise" components with two characteristic timescales of BSO and 16 msec. The PDS contains also a third component: a broad Quasi Periodic Oscillation-like (QPO) feature centered at 0.8 Hz. Neither the shot timescales nor the QPO frequency do not vary with energy, whereas the integrated RMS of all three components shows a positive correlation. In addition, in the 2-20 keV energy band, we found significant evidence for a high frequency component which shows up to 500 Hz in he PDS. In terms of the shot noise model, a Lorentzian fit of this component implies a shot duration of about 1.4 ms. The reality of this component has been tested with the help of simulations. Our observation of the burster 1E1724-3045 reveals timing properties, such as low frequency QPO and high level of RMS for the HFN, also displayed by Black Hole Candidates (BHC). C1 Ctr Etud Spatiale Rayonnements, CNRS, UPS, F-31029 Toulouse, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Boirin, L (reprint author), Ctr Etud Spatiale Rayonnements, CNRS, UPS, F-31029 Toulouse, France. RI Swank, Jean/F-2693-2012 NR 9 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 245 EP 248 DI 10.1016/S0920-5632(98)00218-7 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800046 ER PT J AU Gotthelf, EV Kaspi, VM AF Gotthelf, EV Kaspi, VM TI X-ray emission from the 63 ms radio pulsar PSR J1105-6107 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID STARS 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, Univ Space Res Assoc, Greenbelt, MD 20771 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Univ Space Res Assoc, Greenbelt, MD 20771 USA. EM gotthelf@gsfc.nasa.gov; vicky@space.mit.edu NR 15 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 EI 1873-3832 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 261 EP 264 DI 10.1016/S0920-5632(98)00222-9 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800050 ER PT J AU Gierlinski, M Zdziarski, AA Coppi, PS Poutanen, J Ebisawa, K Johnson, WN AF Gierlinski, M Zdziarski, AA Coppi, PS Poutanen, J Ebisawa, K Johnson, WN TI Thermal/non-thermal model of Cyg X-1 in the soft state SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID X-RAY C1 Jagiellonian Univ, Astron Observ, PL-30244 Krakow, Poland. Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Yale Univ, Dept Astron, New Haven, CT 06520 USA. Univ Uppsala, Astron Observ, S-75120 Uppsala, Sweden. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. RP Gierlinski, M (reprint author), Jagiellonian Univ, Astron Observ, Orla 171, PL-30244 Krakow, Poland. RI Johnson, Neil/G-3309-2014; Poutanen, Juri/H-6651-2016; OI Poutanen, Juri/0000-0002-0983-0049; Gierlinski, Marek/0000-0001-9149-3514 NR 10 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 312 EP 315 DI 10.1016/S0920-5632(98)00231-X PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800059 ER PT J AU de Martino, D Matt, G Barcaroli, R Belloni, T Beuermann, K Bonnet-Bidaud, JM Chiappetti, L Done, C Gansicke, BT Mouchet, M Mukai, K AF de Martino, D Matt, G Barcaroli, R Belloni, T Beuermann, K Bonnet-Bidaud, JM Chiappetti, L Done, C Gansicke, BT Mouchet, M Mukai, K TI BeppoSAX observations of AM Her type stars SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID X-RAY-EMISSION; WHITE-DWARF; HERCULIS; MODE; SPECTROSCOPY; ACCRETION AB First BeppoSAX-NFI observations obtained in the framework of a program aiming to detect simultaneously the soft and hard X-ray emissions and the long term behaviour of AM Her type stars are presented. BL Hyi, the prototipe AM Her and the peculiar V1309 Ori are systems characterized by a strong variability and are elucidative examples of different accretion patterns and modes which can be present in these systems. C1 Osservatorio Astron Capodimonte, I-80131 Naples, Italy. Univ Rome 3, Dipartimento Fis, Rome, Italy. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Sternwarte Gottingen, D-3400 Gottingen, Germany. CEN, Serv Astrophys, Saclay, France. CNR, IFCTR, Milan, Italy. Observ Paris, DAEC, Meudon, France. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD USA. RP de Martino, D (reprint author), Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy. RI Gaensicke, Boris/A-9421-2012; done, chris/D-4605-2016; OI Gaensicke, Boris/0000-0002-2761-3005; done, chris/0000-0002-1065-7239; Chiappetti, Lucio/0000-0001-7857-7908; de Martino, Domitilla/0000-0002-5069-4202 NR 17 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 368 EP 371 DI 10.1016/S0920-5632(98)00242-4 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800070 ER PT J AU Belloni, T Matt, G De Martino, D Chiappetti, L Giovannelli, F Haberl, F Osborne, J Mukai, K Molendi, S Mouchet, M AF Belloni, T Matt, G De Martino, D Chiappetti, L Giovannelli, F Haberl, F Osborne, J Mukai, K Molendi, S Mouchet, M TI The broad-band X-ray spectrum of RE 0751+14 (PQ Gem) SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID INTERMEDIATE POLAR RE-0751+14; EMISSION AB RE 0751+14 is a member of the class of Soft Intermediate Polars. Unlike classical Intermediate Polars, they are characterized by the presence of a soft component in their X-ray spectra, in addition to the hard component. typical of these systems. The broad-band coverage of the Narrow-Field instruments on board BeppoSAX is ideal for the study of such objects. Here we report the preliminary results of the analysis of a BeppoSAX pointing to RE 0751+14. Both components are clearly detected, and their temperature determined (similar to 50 eV and similar to 40 keV), enabling the possibility of studying them simultaneously. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Roma 3, Dipartimento Fis, Rome, Italy. Osservatorio Astron Capodimonte, I-80131 Naples, Italy. CNR, IFCTR, Milan, Italy. CNR, Ist Astrofis Spaziale, I-00044 Frascati, Italy. MPE, Garching, Germany. Univ Leicester, Leicester, Leics, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Belloni, T (reprint author), Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. OI Chiappetti, Lucio/0000-0001-7857-7908; de Martino, Domitilla/0000-0002-5069-4202; Molendi, Silvano/0000-0002-2483-278X NR 24 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 372 EP 375 DI 10.1016/S0920-5632(98)00243-6 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800071 ER PT J AU Maccarone, MC Tavani, M Sacco, B Cusumano, G Gotthelf, E Mukherjee, R Halpern, J Mattox, JR AF Maccarone, MC Tavani, M Sacco, B Cusumano, G Gotthelf, E Mukherjee, R Halpern, J Mattox, JR TI BeppoSAX and ASCA observations of the field containing the gamma-ray transient GRO J1838-04 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID GALACTIC PLANE; EMISSION AB We present preliminary results of BeppoSAX and ASCA observations of the Galactic field containing the unidentified gamma-ray transient GRO J1838-04. Several weak X-ray sources are detected within the EGRET error box. No obvious counterpart of GRO J1838-04 is evident from these observations. More multiwavelength observations are necessary to identify the nature of this non-blazar gamma-ray transient. C1 CNR, IFCAI, I-90146 Palermo, Italy. CNR, IFCTR, I-20133 Milan, Italy. Columbia Univ, CAL, New York, NY 10027 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Boston Univ, Dept Astron, Boston, MA 02215 USA. RP Maccarone, MC (reprint author), CNR, IFCAI, Via Ugo La Malfa 153, I-90146 Palermo, Italy. OI Maccarone, Maria Concetta/0000-0001-8722-0361; Cusumano, Giancarlo/0000-0002-8151-1990 NR 12 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 379 EP 382 DI 10.1016/S0920-5632(98)00245-X PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800073 ER PT J AU Orr, A Parmar, AN Yaqoob, T Guainazzi, M AF Orr, A Parmar, AN Yaqoob, T Guainazzi, M TI BeppoSAX observations of low-energy spectral features in AGN SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID GALAXY MCG-6-30-15; WARM ABSORBER; RAY; ABSORPTION; NUCLEI; ASCA AB The combination of the broad band coverage and moderate spectral resolution of the LEGS and MECS instruments on-board BeppoSAX allow the spectra of AGN to be studied in unprecedented detail down to 0.1 keV. We: describe the calibration and the performance of the LEGS and report on observations of low-energy absorption features in the spectra of both a low (MCG-6-30-15) and a high luminosity (3C 273) AGN. These features provide important diagnostics on the location and nature of the material surrounding the AGN. A comparison of LEGS and ASCA/SIS low energy performance is also presented in the case of 3C 273. C1 European Space Agcy, Estec, Dept Space Sci, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. BeppoSAX Sci Data Ctr, ASI, Nuova Telespazio, I-00131 Rome, Italy. RP Orr, A (reprint author), European Space Agcy, Estec, Dept Space Sci, Div Astrophys, POB 299, NL-2200 AG Noordwijk, Netherlands. OI Parmar, Arvind/0000-0002-3307-6517 NR 18 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 496 EP 500 DI 10.1016/S0920-5632(98)00269-2 PG 5 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800097 ER PT J AU Yaqoob, T McKernan, B AF Yaqoob, T McKernan, B TI A simple new method for analysing gapped time-series: X-ray variability of MCG-6-30-15 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID ACTIVE GALACTIC NUCLEI; GALAXY MCG-6-30-15; POWER SPECTRUM; BLACK-HOLE; LINE 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. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. RP Yaqoob, T (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 515 EP 518 DI 10.1016/S0920-5632(98)00273-4 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800101 ER PT J AU Gruber, DE MacDonald, D Rothschild, RE Boldt, E Mushotzky, RF Fabian, AC AF Gruber, DE MacDonald, D Rothschild, RE Boldt, E Mushotzky, RF Fabian, AC TI Granularity of the diffuse background observed SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID COLD MATTER; RAY; GALAXIES; ORIGIN; NUCLEI AB First results are reported from a program for measuring the field-to-field fluctuation level of the cosmic diffuse background by using differences between the two background positions of each deep exposure with the HEXTE instrument on RXTE. With 8 million live seconds accumulated to date a fluctuation level on the 15-25 keV band is observed which is consistent with extrapolations from the HEAO-1 measurements. Positive results are expected eventually at higher energies. Models of AGN origin will eventually be constrained by this program. C1 Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. RP Gruber, DE (reprint author), Univ Calif San Diego, Ctr Astrophys & Space Sci, 9500 Gilman Dr, La Jolla, CA 92093 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 625 EP 628 DI 10.1016/S0920-5632(98)00310-7 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800122 ER PT J AU Valinia, A Marshall, FE AF Valinia, A Marshall, FE TI RXTE measurement of the diffuse X-ray emission from the Galactic ridge: Implications for the energetics of the interstellar medium SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 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 16 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 629 EP 632 DI 10.1016/S0920-5632(98)00311-9 PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800123 ER PT J 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 TI RXTE observations of GRB afterglows SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 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 flux 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 ang 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. Univ Space Res Assoc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. MIT, Ctr Space Res, Cambridge, MA 02138 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 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; Swank, Jean/F-2693-2012; OI Preece, Robert/0000-0003-1626-7335 NR 13 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 640 EP 645 DI 10.1016/S0920-5632(98)00314-4 PG 6 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800125 ER PT J AU Hurley, K Cline, T Frontera, F Dal Fiume, D Orlandini, M Costa, E Piro, L Feroci, RI AF Hurley, K Cline, T Frontera, F Dal Fiume, D Orlandini, M Costa, E Piro, L Feroci, RI TI Ulysses/BeppoSAX observations of cosmic gamma-ray-bursts SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT Symposium on the Active X-ray Sky CY OCT 21-24, 1996 CL ROME, ITALY ID 28 FEBRUARY 1997 AB BeppoSAX has been added to the 3rd Interplanetary Network of gamma-ray burst detectors. Of the 8 events observed to date by Ulysses and the BeppoSAX Gamma Ray Burst Monitor (GRBM), four have been localized by triangulation, resulting in annuli whose 3 sigma widths are as small as 63''. These data give error boxes whose sizes are sometimes smaller than those obtained with the SAX Wide Field Camera (WFC). They can be used to confirm the association between fading X-ray and optical sources and gamma-ray bursts. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Ferrara, I-44100 Ferrara, Italy. CNR, Ist Tesre, I-40129 Bologna, Italy. CNR, Ist Astrofis Spaziale, I-00044 Frascati, Italy. RP Hurley, K (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RI PIRO, LUIGI/E-4954-2013; Orlandini, Mauro/H-3114-2014; OI PIRO, LUIGI/0000-0003-4159-3984; Orlandini, Mauro/0000-0003-0946-3151; Costa, Enrico/0000-0003-4925-8523; Feroci, Marco/0000-0002-7617-3421 NR 12 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JAN PY 1999 VL 69 IS 1-3 BP 660 EP 663 DI 10.1016/S0920-5632(98)00317-X PG 4 WC Physics, Particles & Fields SC Physics GA 121WM UT WOS:000076038800128 ER PT B AU Pickett, BK Cassen, P Durisen, RH Link, R AF Pickett, BK Cassen, P Durisen, RH Link, R BE Miyama, SM Tomisaka, K Hanawa, T TI Three-dimensional hydrodynamics of protostellar disks: The effects of thermal energetics SO NUMERICAL ASTROPHYSICS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT International Conference on Numerical Astrophysics 1998 (NAP 98) CY MAR 10-13, 1998 CL TOKYO, JAPAN SP Natl Astron Observ Japan, Theoret Astrophys Div, NAOJ, Solar Phys Div, NAOJ, Astron Date Anal Ctr, Minist Educ, Sci, Culture & Sport ID ROTATING PROTOSTARS AB We use a second-order three-dimensional hydrodynamics code with self-gravity to investigate the role that thermal energetics plays in the development of nonaxisymmetric instabilities in protostellar disks. The initial axisymmetric equilibrium state is a continuous, fluid star/disk system, in which the star, the disk, and the star/disk boundary are resolved in 3D in our hydrodynamics code. An adiabatic evolution is compared to two previous simulations of the same model in which either local isentropy or local isothermality is maintained in the disk throughout the calculation. In all three cases, the model is highly unstable to multiple low-order nonaxisymmetric disturbances which induce significant mass and angular momentum transport in a few dynamical times. The star and star/disk boundary are dominated by three- and four-armed disturbances, whereas the disk is susceptible to a two-armed spiral. These disturbances saturate at moderate nonlinear amplitude in the adiabatic and isentropic evolutions; the same instabilities in the isothermal evolution lead to the disruption of the disk and concentration of material into several dense, thin arcs and arclets. Figures, tables and animations are included in the CD-ROM supplement. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Pickett, BK (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5566-0 J9 ASTROPHYS SPACE SC L PY 1999 VL 240 BP 177 EP 178 PG 2 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BN22F UT WOS:000081148900056 ER PT B AU Meier, DL Godon, P AF Meier, DL Godon, P BE Miyama, SM Tomisaka, K Hanawa, T TI Multi-dimensional astrophysical structural analysis - A new field of numerical astrophysics SO NUMERICAL ASTROPHYSICS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT International Conference on Numerical Astrophysics 1998 (NAP 98) CY MAR 10-13, 1998 CL TOKYO, JAPAN SP Natl Astron Observ Japan, Theoret Astrophys Div, NAOJ, Solar Phys Div, NAOJ, Astron Date Anal Ctr, Minist Educ, Sci, Culture & Sport 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 2 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5566-0 J9 ASTROPHYS SPACE SC L PY 1999 VL 240 BP 403 EP 404 PG 2 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BN22F UT WOS:000081148900123 ER PT J AU Shaw, PT Chao, SY Fu, LL AF Shaw, PT Chao, SY Fu, LL TI Sea surface height variations in the South China Sea from satellite altimetry SO OCEANOLOGICA ACTA LA English DT Article DE South China Sea; sea level; wind stress curl; altimetry; Topex Poseidon ID OCEAN TIDES; EL-NINO; TOPEX/POSEIDON; REANALYSIS; WATER AB Sea surface elevation in the South China Sea is examined in the Topex/Poseidon altimeter data from 1992 to 1995. Sea level anomalies are smoothed along satellite tracks and in time with tidal errors reduced by harmonic analysis. The smoothed data are sampled every ten days with an along-track separation of about 40 km. The data reveal significant annual variations in sea level. In winter, low sea level is over the entire deep basin with two local lows centred off Luzon and the Sunda Shelf. In summer, sea level is high off Luzon and off the Sunda Shelf, and a low off Vietnam separates the two highs. The boundary between the Vietnam low and Sunda high coincides with the location of a jet leaving the coast of Vietnam described in earlier studies. Principal component analysis shows that the sea level variation consists mainly of two modes, corresponding well to the first two modes of the wind stress curl. Mode 1 represents the oscillation in the southern basin and shows little inter-annual variation. The mode 2 oscillation is weak in the southern basin and is strongest off central Vietnam. During the winters of 1992-1993 and 1994-1995 and the following summers, the wind stress curl is weak, and the mode 2 sea level variation in the northern basin is reduced, resulting in weaker winter and summer gyres. Weakening of the Vietnam low in summer implies diminishing of the eastward jet leaving the coast of Vietnam. The results are consistent with model simulations. (C) Elsevier, Paris / Ifremer / Cnrs / Ird. C1 N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Raleigh, NC 27695 USA. Univ Maryland, Horn Point Environm Lab, Ctr Environm Sci, Cambridge, MD 21613 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shaw, PT (reprint author), N Carolina State Univ, Dept Marine Earth & Atmospher Sci, POB 8208, Raleigh, NC 27695 USA. NR 20 TC 113 Z9 134 U1 1 U2 17 PU GAUTHIER-VILLARS/EDITIONS ELSEVIER PI PARIS PA 23 RUE LINOIS, 75015 PARIS, FRANCE SN 0399-1784 J9 OCEANOL ACTA JI Oceanol. Acta PD JAN-FEB PY 1999 VL 22 IS 1 BP 1 EP 17 DI 10.1016/S0399-1784(99)80028-0 PG 17 WC Oceanography SC Oceanography GA 175KW UT WOS:000079093400001 ER PT B AU Digby, S Antczak, T Leben, R Born, G Barth, S Cheney, R Foley, D Goni, GJ Jacobs, G Shay, N AF Digby, S Antczak, T Leben, R Born, G Barth, S Cheney, R Foley, D Goni, GJ Jacobs, G Shay, N GP MTS MTS TI Altimeter data for operational use in the marine environment SO OCEANS '99 MTS/IEEE : RIDING THE CREST INTO THE 21ST CENTURY, VOLS 1-3 LA English DT Proceedings Paper CT MTS/IEEE Conference on Riding the Crest Into the 21st Century (OCEANS 99) CY SEP 13-16, 1999 CL SEATTLE, WA SP Marine Technol Soc, Ocean Engn Soc, Inst Elect & Electr Engn AB TOPEX/Poseidon has been collecting altimeter data continuously since October 1992. Altimeter data have been used to produce maps of sea surface height, geostrophic velocity, significant wave height, and wind speed. This information is of proven use to mariners as well as to the scientific community. Uses of the data include commercial and recreational vessel routing, ocean acoustics, input to geographic information systems developed for the fishing industry, identification of marine mammal habitats, fisheries management, and monitoring ocean debris. As with sea surface temperature data from the Advanced Very High Resolution Radiometer (AVHRR) in the late 1980s and early 1990s, altimeter data from TOPEX/Poseidon and ERS-1 and -2 are in the process of being introduced to the marine world for operational maritime use. It is anticipated that over the next few years companies that specialize in producing custom products for shipping agencies, fisheries and yacht race competitors will be incorporating altimeter data into their products. The data are also being incorporated into weather and climate forecasts by operational agencies both in the US and Europe. This paper will discuss these products, their uses, operational demonstrations and means of accessing the data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Digby, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 7 TC 0 Z9 0 U1 0 U2 3 PU MARINE TECHNOLOGY SOC PI WASHINGTON PA 1828 L ST NW,SUITE 906, WASHINGTON, DC 20035 USA BN 0-933957-24-6 PY 1999 BP 605 EP 613 PG 3 WC Engineering, Marine; Engineering, Electrical & Electronic; Oceanography SC Engineering; Oceanography GA BP25F UT WOS:000084482300093 ER PT B AU Dufficy, T AF Dufficy, T BE Harmon, D TI Sharing a world of resources SO ON THE FRONTIERS OF CONSERVATION: PROCEEDINGS OF THE TENTH CONFERENCE ON RESEARCH AND RESOURCE MANAGEMENT IN PARKS AND ON PUBLIC LANDS LA English DT Proceedings Paper CT 10th Conference on Research and Resource Management in Parks and on Public Lands/George-Wright-Society Biennial Conference CY MAR 22-26, 1999 CL ASHEVILLE, NC SP George Wright Soc, US Natl Pk Serv, US Geol Survey, Biol Resources Div C1 NASA, Goddard Space Flight Ctr, Natl Pk Serv, Off Publ Affairs, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU GEORGE WRIGHT SOCIETY, INC. PI HANCOCK PA PO BOX 65, HANCOCK, MI 49930-0065 USA PY 1999 BP 31 EP 33 PG 3 WC Environmental Studies; Public Administration SC Environmental Sciences & Ecology; Public Administration GA BP35H UT WOS:000084811100004 ER PT S AU Smith, DD Yoon, Y Boyd, RW Banks, C Paley, MS AF Smith, DD Yoon, Y Boyd, RW Banks, C Paley, MS BE Lal, RB Frazier, DO TI Transmission measurements of the third-order susceptibility of gold SO OPERATIONAL CHARACTERISTICS AND CRYSTAL GROWTH OF NONLINEAR OPTICAL MATERIALS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Operational Characteristics and Crystal Growth of Nonlinear Optical Materials CY JUL 19-20, 1999 CL DENVER, CO SP SPIE DE effective medium theory; optical composites; nonlinear optics; z-scan; percolation; gold colloid AB Gold nanoparticle composites are known to display large optical nonlinearities. In order to assess the validity of generalized effective medium theories (EMTs) for describing the optical properties of metal nanoparticle composites, we have used the z-scan technique to measure the third-order susceptibility of gold nanoparticle composites across the entire range of fill fractions. These materials range from low concentration statistically random gold sols, to aggregated thin (two-dimensional) composite films, to quasi-bulk thin films above the percolation threshold. These measurements allow the nonlinearity of gold to be determined both directly and by deduction from applicable effective medium theories. We compare our results with predictions which ascribe the nonlinear response to a Fermi-smearing mechanism. We demonstrate that the nonlinear susceptibility changes sign due to a phase shift between the applied field and the local field, and that this sign change occurs at the percolation threshold. Further for films whose thickness is less than an optical wavelength we introduce a two-dimensional form of the Maxwell Garnett model. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Smith, DD (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, ES-76, Huntsville, AL 35812 USA. NR 19 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 0-8194-3279-2 J9 P SOC PHOTO-OPT INS PY 1999 VL 3793 BP 74 EP 83 DI 10.1117/12.351400 PG 10 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Optics SC Materials Science; Optics GA BN65Z UT WOS:000082519600010 ER PT S AU Abdeldayem, H Frazier, DO Paley, MS AF Abdeldayem, H Frazier, DO Paley, MS BE Lal, RB Frazier, DO TI All-optical nand logic gate using organic materials SO OPERATIONAL CHARACTERISTICS AND CRYSTAL GROWTH OF NONLINEAR OPTICAL MATERIALS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Operational Characteristics and Crystal Growth of Nonlinear Optical Materials CY JUL 19-20, 1999 CL DENVER, CO SP SPIE DE optical logic gate; third order nonlinear optics; organic materials; optical devices ID REVERSE SATURABLE ABSORPTION; CONJUGATED POLYMER; SOLUBLE POLYDIACETYLENES AB Conventional electronic logic circuits in today's computers impose extreme limitations on computational speed, complexity, compactness. In highly dense electronic logic circuits the connections simply cannot handle electrical signals swiftly and reliably. On the other hand, optical interconnections and optical integrated circuits are sought to provide answers to future computing and compactness demands. Optical devices are immune from electromagnetic interference and free from electrical short circuits. They have low-loss transmission and provide large bandwidth (i.e. multiplexing capability) and are manufacturable in compact sizes, are lightweight and inexpensive. Recently, we demonstrated an all-optical NAND logic gate having nanosecond response time by waveguiding two collinear nanosecond white light caused by focusing a pulsed Nd:YAG laser at 1064 nm along with a cw He-Ne laser at 632.8 nm through a polydiacetylene derivative of 2-methyl-4-nitroaniline (PDAMNA) thin film. The physics involved in the process was explained based on Z-scan studies of the same polymer using He-Ne laser. These studies show an induced absorption by an excited state, resulting in a reverse saturable absorption (RSA) in the system. The RSA figure of merit in PDAMNA was estimated. The size and sign of the real and imaginary parts of the third order nonlinearity were evaluated. These studies also demonstrate for the first time to our knowledge, that reverse saturable absorption in an optical system can be used to build similar logic gates. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Abdeldayem, H (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NR 19 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 0-8194-3279-2 J9 P SOC PHOTO-OPT INS PY 1999 VL 3793 BP 113 EP 119 DI 10.1117/12.351404 PG 7 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Optics SC Materials Science; Optics GA BN65Z UT WOS:000082519600014 ER PT B AU Noriega-Crespo, A AF Noriega-Crespo, A BE Guenther, EW Stecklum, B Klose, S TI The spectroscopic properties of embedded stellar outflows SO OPTICAL AND INFRARED SPECTROSCOPY OF CIRCUMSTELLAR MATTER SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Workshop on Optical and Infrared Spectroscopy of Circumstellar Matter CY MAR 10-12, 1999 CL TAUTENBURG, GERMANY ID HERBIG-HARO OBJECTS; MOLECULAR OUTFLOWS; EXCITING SOURCE; JET; EMISSION; NGC-1333; HYDROGEN; HH-7-11 AB The relationship between optical stellar jets and embedded molecular outflows is explored through the HH 7-11 system, One of the best studied stellar outflows. Preliminary results from the ISO spectrometers (SWS & LWS) are presented. The data includes the HH 7-11 flow, its red-shifted counterpart and the SVS 13 source, in the active star formation region NGC 1333. Atomic/ionic ([OI] 63 mu m, [OI] 145 mu m, [SiII] 34.8 mu m, [CII] 158 mu m) and molecular (H(2), CO, H(2)O) lines are detected at various positions along the bipolar flow. At far infrared wavelengths very little difference was found between the properties of the two HH 7-11 outflow lobes. An interesting result since the red-shifted,lobe is embedded. Unlike the theoretical prediction from low velocity molecular:C-shock models, H(2)O has a minor role in the overall cooling of the outflow. C1 CALTECH, Jet Prop Lab, Infrared Proc & Anal Ctr, Pasadena, CA 91125 USA. RP Noriega-Crespo, A (reprint author), CALTECH, Jet Prop Lab, Infrared Proc & Anal Ctr, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. EM alberto@ipac.caltech.edu NR 29 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 1-58381-014-5 J9 ASTR SOC P PY 1999 VL 188 BP 83 EP 92 PG 10 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BP47K UT WOS:000085237700011 ER PT S AU Zimmerli, GA Min, KY Goldburg, WI AF Zimmerli, GA Min, KY Goldburg, WI BE Cha, SS BryanstonCross, PJ Mercer, CR TI Measuring the probability distribution of velocity differences using homodyne correlation spectroscopy SO OPTICAL DIAGNOSTICS FOR FLUIDS/HEAT/COMBUSTION AND PHOTOMECHANICS FOR SOLIDS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Diagnostics for Fluids Heat Combustion and Photomechanics for Solids CY JUL 21-23, 1999 CL DENVER, CO SP SPIE DE homodyne correlation spectroscopy; turbulence; probability density function ID PHOTON-CORRELATION SPECTROSCOPY; TURBULENCE AB A novel method of measuring the probability density of velocity differences in turbulent flow is described. The method is based on the light-scattering technique known as homodyne correlation spectroscopy. Using fiber optic probes to image two different scattering volumes in a turbulent fluid, it is possible to recover the probability density function (p.d.f.) of velocity differences without invoking Taylor's frozen turbulence assumption. The design of the instrument is described, together with the optical alignment procedure. Some of the fundamental limitations to the accuracy of the technique are discussed. Measurements of the p.d.f. from uniform and turbulent flow are presented, where the turbulence was generated using a mechanical stirrer in a beaker of water. C1 NASA, Glenn Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Zimmerli, GA (reprint author), NASA, Glenn Ctr Micrograv Res, MS 110-3, Cleveland, OH 44135 USA. NR 11 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 0-8194-3269-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3783 BP 46 EP 53 DI 10.1117/12.365761 PG 8 WC Instruments & Instrumentation; Mechanics; Materials Science, Characterization & Testing; Optics SC Instruments & Instrumentation; Mechanics; Materials Science; Optics GA BN97Z UT WOS:000083741900005 ER PT S AU Fleming, GA Burner, AW AF Fleming, GA Burner, AW BE Cha, SS BryanstonCross, PJ Mercer, CR TI Deformation measurements of smart aerodynamic surfaces SO OPTICAL DIAGNOSTICS FOR FLUIDS/HEAT/COMBUSTION AND PHOTOMECHANICS FOR SOLIDS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Diagnostics for Fluids Heat Combustion and Photomechanics for Solids CY JUL 21-23, 1999 CL DENVER, CO SP SPIE DE Video Model Deformation; Projection Moire Interferometry; VMD; PMI; Smart Wing; shape memory alloy; SMA; twist ID PROJECTION AB Video Model Deformation (VMD) and Projection Moire Interferometry (PMI) were used to acquire wind tunnel model deformation measurements of the Northrop Grumman-built Smart Wing tested in the NASA Langley Transonic Dynamics Tunnel. The F18-E/F planform Smart Wing was outfitted with embedded shape memory alloys to actuate a seamless trailing edge aileron and flap, and an embedded torque tube to generate wing twist. The VMD system was used to obtain highly accurate deformation measurements at three spanwise locations along the main body of the wing, and at spanwise locations on the flap and aileron. The PMI system was used to obtain full-field wing shape and deformation measurements over the entire wing lower surface. Although less accurate than the VMD system, the PMI system revealed deformations occurring between VMD target rows indistinguishable by VMD. This paper presents the VMD and PMI techniques and discusses their application in the Smart Wing test. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Fleming, GA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 22 TC 4 Z9 4 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 0-8194-3269-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3783 BP 228 EP 238 DI 10.1117/12.365741 PG 11 WC Instruments & Instrumentation; Mechanics; Materials Science, Characterization & Testing; Optics SC Instruments & Instrumentation; Mechanics; Materials Science; Optics GA BN97Z UT WOS:000083741900024 ER PT S AU Tuma, M Gruhlke, R Brown, T AF Tuma, M Gruhlke, R Brown, T BE Cha, SS BryanstonCross, PJ Mercer, CR TI Evidence of enhanced fluorescence via cross coupling in an integrated thin-film fluorescence sensor SO OPTICAL DIAGNOSTICS FOR FLUIDS/HEAT/COMBUSTION AND PHOTOMECHANICS FOR SOLIDS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Diagnostics for Fluids Heat Combustion and Photomechanics for Solids CY JUL 21-23, 1999 CL DENVER, CO SP SPIE DE fluorescence sensor; surface plasmon cross coupling; enhanced fluorescence ID MOLECULAR FLUORESCENCE; GAS SENSORS; SURFACE; SHIFTS; NO2 AB A fluorescence sensor-system has been proposed that integrates optical and electronic components in a thin-film geometry. Predicted properties of this sensor include: increased sensitivity, shielding from unwanted radiation, wavelength filtering, potential operation at high temperatures, and miniaturization. The sensor can be tuned to measure a wide variety of species by varying its thin-film corrugation period. The optical properties of the sensor are determined, in large part, by optical cross coupling through a corrugated metal film and enhanced fluorescence. Measurements evaluating these processes are presented. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Tuma, M (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 18 TC 2 Z9 2 U1 4 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 0-8194-3269-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3783 BP 339 EP 346 DI 10.1117/12.365754 PG 8 WC Instruments & Instrumentation; Mechanics; Materials Science, Characterization & Testing; Optics SC Instruments & Instrumentation; Mechanics; Materials Science; Optics GA BN97Z UT WOS:000083741900037 ER PT J AU Tveekrem, JL Keski-Kuha, RAM Webb, AT AF Tveekrem, JL Keski-Kuha, RAM Webb, AT TI Gas permeability through thin-foil x-ray filters SO OPTICAL ENGINEERING LA English DT Article DE x ray; filter; permeation; leak rate; outgassing; contamination AB We have measured the permeation rates of helium and water through thin-foil UV-blocking filters used in the ASTRO-E/X-Ray Spectrometer (XRS) instrument. In the XRS program, there is a concern that outgassed contaminants such as water could permeate through the outermost filter, which will be at room temperature, and freeze on the inner filters, which will be at cryogenic temperatures, The filters tested consisted of similar to 1000 Angstrom Al on similar to 1000 Angstrom of either Lexan or polyimide. Results discussed include the permeation rate as a function of pressure difference across a filter, the ratio of helium to water permeation rate, and the effect of the aluminum layer thickness on permeation. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)02301-6]. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, ManTech Syst Engn Corp, Greenbelt, MD 20771 USA. RP Tveekrem, JL (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, Code 551, Greenbelt, MD 20771 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JAN PY 1999 VL 38 IS 1 BP 120 EP 123 DI 10.1117/1.602248 PG 4 WC Optics SC Optics GA 157XY UT WOS:000078088000017 ER PT S AU Zhao, F Logan, JE Shaklan, S Shao, M AF Zhao, F Logan, JE Shaklan, S Shao, M BE Yamaguchi, I TI A common-path, multi-channel heterodyne laser interferometer for sub-nanometer surface metrology SO OPTICAL ENGINEERING FOR SENSING AND NANOTECHNOLOGY (ICOSN'99) SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Conference on Optical Sensing and Nanotechnology (ICOSN 99) CY JUN 16-18, 1999 CL YOKOHAMA, JAPAN SP Opt Soc Japan, SPIE DE heterodyne interferometry; metrology; nano-technology ID PHASE-SHIFTING INTERFEROMETRY AB A multi-channel heterodyne laser interferometer is proposed for measurement of optical surface deformations at the sub-nanometer level. This interferometer employs a common-path configuration and heterodyne detection, by which fringe errors due to laser frequency fluctuations and optical path variations due to vibration can be reduced. By measuring the heterodyne signal phase among sub-apertures (pixels) with a 2-D detector array, the surface height can be reconstructed and surface deformation can be measured by comparing consecutive measurements. Detection of sub-nanometer level surface deformation is achieved using high precision digital phase meters and athermalized opto-mechanical systems. This paper describes the interferometer design criteria and experiment methodologies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zhao, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 11 Z9 11 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 0-8194-3214-8 J9 P SOC PHOTO-OPT INS PY 1999 VL 3740 BP 642 EP 645 DI 10.1117/12.347766 PG 4 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BN88B UT WOS:000083313900143 ER PT S AU Halverson, PG Johnson, DR Kuhnert, A Shaklan, SB Spero, R AF Halverson, PG Johnson, DR Kuhnert, A Shaklan, SB Spero, R BE Yamaguchi, I TI A multichannel averaging phasemeter for picometer precision laser metrology SO OPTICAL ENGINEERING FOR SENSING AND NANOTECHNOLOGY (ICOSN'99) SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Conference on Optical Sensing and Nanotechnology (ICOSN 99) CY JUN 16-18, 1999 CL YOKOHAMA, JAPAN SP Opt Soc Japan, SPIE DE laser interferometry; picometer metrology; nanometer metrology; laser metrology; heterodyne interferometry; VME data acquisition; FPGA circuits; cyclic averaging ID STELLAR INTERFEROMETER; GAUGES AB The Micro-Arcsecond Metrology (MAM) team at the Jet Propulsion Laboratory has developed a precision phasemeter for the Space Interferometry Mission (SIM). The current version of the phasemeter is well-suited for picometer accuracy distance measurements and tracks at speeds up to 50 cm/sec, when coupled to SIM's 1.3 micron wavelength heterodyne laser metrology gauges. Since the phasemeter is implemented with industry standard FPGA chips, other accuracy/speed tradeoff points can be programmed for applications such as metrology for earth-based long-baseline astronomical interferometry (planet finding), and industrial applications such as translation stage and machine tool positioning. The phasemeter is a standard VME module, supports 6 metrology gauges, a 128 MHz clock, has programmable hardware averaging, and a maximum range of 2(32) cycles (2000 meters at 1.3 microns). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Halverson, PG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 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 0-8194-3214-8 J9 P SOC PHOTO-OPT INS PY 1999 VL 3740 BP 646 EP 649 DI 10.1117/12.347767 PG 4 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BN88B UT WOS:000083313900144 ER PT S AU Jacobson, D Bunton, P AF Jacobson, D Bunton, P BE Stahl, HP TI Development of lightweight mirror technology for the NGST program SO OPTICAL MANUFACTURING AND TESTING III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Optical Manufacturing and Testing III CY JUL 20-23, 1999 CL DENVER, CO SP SPIE DE optical; manufacturing; mirror; segmented; NGST AB Recognizing the need to launch larger aperture telescopes to orbit with current launch capability, the Next Generation Space Telescope (NGST) program began in 1997, an aggressive technology development effort in lightweight optics. This effort has developed technologies in Silicon Carbide, Beryllium, silicon, glass and hybrid mirrors to name a few. The advancement of mirror technology to below the 15 kg/m(2) areal density is challenging enough without the added requirements for NGST that the mirror operate at approximately 35 Kelvin. This paper will discuss the various NGST technology developments including applications relative to bonding or joining mirror materials, subscale developments, the minor system demonstrator program, the advanced mirror demonstrator program and development of the minor test program. Specific attention will be given to technical issues related to lightweight minor development and processing. Other issues to be addressed are the development of the roadmap to the NGST flight minor development and to assess the technology readiness for NGST. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Jacobson, D (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 2 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 0-8194-3268-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3782 BP 114 EP 122 DI 10.1117/12.369177 PG 3 WC Optics SC Optics GA BP26G UT WOS:000084509400012 ER PT S AU Smith, WS Hraba, JF Jones, GW AF Smith, WS Hraba, JF Jones, GW BE Stahl, HP TI Manufacturing and testing an 8.3 meter astronomical mirror SO OPTICAL MANUFACTURING AND TESTING III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Optical Manufacturing and Testing III CY JUL 20-23, 1999 CL DENVER, CO SP SPIE AB The optical manufacturing facilities, equipment and processes used to manufacture and test an 8.3 meter diameter primary mirror are described. The very successful first light of the SUBARU telescope gives the final confirmation of the manufacturing and testing procedures. This achievement resulted from the cooperative efforts of three organizations working together to produce what is currently the largest and best optical quality monolithic 8 meter class astronomical telescope. The processes outlined here have set a new standard in optical quality for all future large astronomical instruments. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Smith, WS (reprint author), NASA, George C Marshall Space Flight Ctr, SD70, Huntsville, AL 35812 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 0-8194-3268-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3782 BP 157 EP 168 DI 10.1117/12.369238 PG 4 WC Optics SC Optics GA BP26G UT WOS:000084509400016 ER PT S AU Fischer, DG Ovryn, B AF Fischer, DG Ovryn, B BE Stahl, HP TI Surface profilometry of a thick liquid lens on a solid surface using a high numerical aperture phase shifting laser feedback interferometer SO OPTICAL MANUFACTURING AND TESTING III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Optical Manufacturing and Testing III CY JUL 20-23, 1999 CL DENVER, CO SP SPIE ID MICROLENS FABRICATION AB We have developed a model that predicts the effective optical path length (OPL) through a thick, refractive specimen on a reflective substrate as measured with a high numerical aperture, confocal interference microscope. Assuming an infinitesimal pinhole, only one "magic ray" contributes to the measured OPL. It is possible to correct for the refractive errors and to unambiguously interpret the data. We present a comparison of our model predictions with experimental measurements of a fluid drop on a silicon substrate, obtained with a phase shifting laser feedback microscope. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. RP Fischer, DG (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, MS 110-3,21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 19 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 0-8194-3268-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3782 BP 378 EP 387 DI 10.1117/12.369214 PG 2 WC Optics SC Optics GA BP26G UT WOS:000084509400038 ER PT S AU Juday, RD Rollins, JM Monroe, SE Morelli, MV AF Juday, RD Rollins, JM Monroe, SE Morelli, MV BE Casasent, DP Chao, TH TI Optical results with Rayleigh quotient discrimination filters SO OPTICAL PATTERN RECOGNITION X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Pattern Recognition X CY APR 07-08, 1999 CL ORLANDO, FL SP SPIE - Int Soc Opt Engn DE optimal filters; discrimination; optical correlation; pattern recognition AB We report experimental laboratory results using filters that optimize the Rayleigh quotient [Richard D. Juday, "Generalized Rayleigh quotient approach to filter optimization", JOSA-A 15(4), 777-790 (April 1998)] for discriminating between two similar objects. That quotient is the ratio of the correlation responses to two differing objects. In distinction from previous optical processing methods it includes the phase of both objects - not the phase of only the "accept" object - in the computation of the filter. In distinction from digital methods it is explicitly constrained to optically realizable filter values throughout the optimization process. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Juday, RD (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 10 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 0-8194-3189-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3715 BP 60 EP 70 DI 10.1117/12.341327 PG 11 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BM94Q UT WOS:000080212700006 ER PT S AU Juday, RD AF Juday, RD BE Casasent, DP Chao, TH TI Quantifying the utility of a spatial light modulator SO OPTICAL PATTERN RECOGNITION X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Pattern Recognition X CY APR 07-08, 1999 CL ORLANDO, FL SP SPIE - Int Soc Opt Engn DE optimal filter; optical correlation; spatial light modulator AB Some methods of quantifying the utility of a spatial light modulator for optical correlation pattern recognition are introduced and compared with earlier methods. An SLM should be judged according to the problem it is being used in, and the metric optimized in the filter construction can be used to measure the utility of the SLM. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Juday, RD (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code ER5, Houston, TX 77058 USA. NR 3 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 0-8194-3189-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3715 BP 108 EP 111 DI 10.1117/12.341290 PG 4 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BM94Q UT WOS:000080212700011 ER PT S AU Herren, KA Gregory, DA AF Herren, KA Gregory, DA BE Casasent, DP Chao, TH TI The calculation of fractal dimension in the presence of non-fractal clutter SO OPTICAL PATTERN RECOGNITION X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Pattern Recognition X CY APR 07-08, 1999 CL ORLANDO, FL SP SPIE - Int Soc Opt Engn DE image processing; fractals; fractal dimension; wavelets; wavelet transform ID WAVELET TRANSFORM AB The area of information processing has grown dramatically over the last 50 years. In the areas of image processing and information storage the technology requirements have far outpaced the ability of the community to meet demands. The need for faster recognition algorithms and more efficient storage of large quantities of data has forced the user to accept less than lossless retrieval of that data for analysis. In addition to clutter which is not the object of interest in the data set, often the throughput requirements forces the user to accept "noisy" data and to tolerate the clutter inherent in that data. It has been shown that some of this clutter, both the unavoidable clutter (clouds, trees, etc) as well as the noise introduced on the data by processing requirements can be modeled as fractal or fractal-like. Traditional methods, using Fourier deconvolution on these sources of noise in frequency space, lead to loss of signal and can, in many cases, completely eliminate the target of interest. One parameter used to characterize fractal-like noise, the fractal dimension, has been investigated and fractal dimension images are presented. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Herren, KA (reprint author), NASA, George C Marshall Space Flight Ctr, EB52, Huntsville, AL 35812 USA. NR 13 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 0-8194-3189-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3715 BP 216 EP 227 DI 10.1117/12.341303 PG 12 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BM94Q UT WOS:000080212700023 ER PT S AU Zhou, HY Chao, TH AF Zhou, HY Chao, TH BE Casasent, DP Chao, TH TI MACH filter synthesizing for detecting targets in cluttered environment for gray-scale optical correlator SO OPTICAL PATTERN RECOGNITION X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Pattern Recognition X CY APR 07-08, 1999 CL ORLANDO, FL SP SPIE - Int Soc Opt Engn DE correlation filter synthesizing; gray-scale optical correlator; noise and clutter suppression ID UNCONSTRAINED CORRELATION FILTERS; NOISE AB We have recently demonstrated a compact, high speed, gray-scale optical correlator for target detection. The capability of the direct gray-scale scene input and the gray-scale (real-valued) filter modulation enables us to implement a near-theoretical optimal filter on the optical correlator. This paper describes filter synthesizing algorithm for detecting targets in cluttered background input scene and the projection from the complex filter version to the real version for implementation on the gray-scale optical correlator. It is based on optimal-tradeoff MACH filter. It was found that using an appropriate simulated noise image to substitute the commonly used white noise in the filter design procedure is a very effective way to suppress clutter noise while maintain high tolerance for distortion. Both simulation and experimental results are provided. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zhou, HY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 303-300, Pasadena, CA 91109 USA. NR 10 TC 21 Z9 21 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 0-8194-3189-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3715 BP 394 EP 398 DI 10.1117/12.341322 PG 5 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BM94Q UT WOS:000080212700041 ER PT S AU Chao, TH Reyes, G Zhou, HY AF Chao, TH Reyes, G Zhou, HY BE Casasent, DP Chao, TH TI Automatic Target Recognition field demonstration using a grayscale optical correlator SO OPTICAL PATTERN RECOGNITION X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Pattern Recognition X CY APR 07-08, 1999 CL ORLANDO, FL SP SPIE - Int Soc Opt Engn DE grayscale optical correlator; automatic target recognition; real-time field demonstration; optical MACH correlation filter ID CORRELATION FILTERS AB Jet Propulsion Laboratory (JPL) has recently developed a camcorder-sized grayscale optical correlator (GOC) [1] for realtime automatic target recognition applications. Key features of this GOC include: A grayscale input SLM to accommodate direct interface with the input imaging sensor, A real-valued (bipolar-amplitude) filter spatial light modulator to enable use of a MACH (Maximum Average Correlation Height) composite correlation filter algorithm, compact and portable. This GOC architecture has greatly improve the system complexity by removing the need of preprocess (binarization) the input, and the powerful MACH composite filter has greatly reduced the number of filter templates. Updating of the GOC system will be described in this paper, a recent real-time field demonstration for target recognition and tracking at Mojave Dessert, CA will also be reported. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chao, TH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 15 Z9 15 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 0-8194-3189-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3715 BP 399 EP 406 DI 10.1117/12.341323 PG 8 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BM94Q UT WOS:000080212700042 ER PT S AU Keys, AS Fork, RL Nelson, TR Loehr, JP AF Keys, AS Fork, RL Nelson, TR Loehr, JP BE Beiser, L Sagan, SF Marshall, GF TI Resonant transmissive modulator construction for use in beam steering array SO OPTICAL SCANNING: DESIGN AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Scanning - Design and Application CY JUL 21-22, 1999 CL DENVER, CO SP SPIE DE optical beam steering; diffractive optics; distributed Bragg reflector; quantum confined stark effect; simulated annealing; phase modulator; electro-optic modulator; multi-layer stack ID ELECTROMAGNETIC MODE DENSITY; QUANTUM-WELL STRUCTURES; BRAGG-REFLECTOR; WAVE-GUIDES; BAND-GAP; ELECTROABSORPTION; ABSORPTION; FINITE; LIGHT; EDGE AB We describe a design for an agile, electronically-configurable, optical beam steering array to be used in directional free-space transmission of optical signals. The proposed device employs a one-dimensional array of tunable resonant transmissive modulators constructed from customized multi-layered stacks of dielectric materials. Each modulator may be individually configured to transmit an optical signal with a known amount of phase and group velocity modulation. Proper configuration of each individual modulator results in diffractive interactions between multiple modulator outputs, providing a method for directional optical signal transmission. Of particular focus within this paper is the design of the individual modulator. We generate custom transmission functions by varying the parameters describing the modulator's specific construction, such as number of layers within the multi-layer stack, refractive indices of stack materials, layer thickness, and combinations of periodic versus non-periodic layer repetitions. A computational optimization of the variables describing the stack's construction strives to maximize the amount of optical signal modulation obtainable within defined limits. Our optimization is based largely on maximizing transmitted phase delay. We discuss trade-offs between methods of increasing device performance versus practical limitations of fabrication technologies. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Keys, AS (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 24 TC 2 Z9 2 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 0-8194-3273-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3787 BP 115 EP 125 DI 10.1117/12.351636 PG 11 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BN65X UT WOS:000082518800012 ER PT S AU Smith, W Larar, A Zhou, D Sisko, C Li, J Huang, B Howell, H Revercomb, H Cousins, D Gazarik, M Mooney, D Mango, S AF Smith, W Larar, A Zhou, D Sisko, C Li, J Huang, B Howell, H Revercomb, H Cousins, D Gazarik, M Mooney, D Mango, S BE Larar, AM TI NAST-I: Results from revolutionary aircraft sounding spectrometer SO OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE remote sensing; spectrometry; infrared radiation; Fourier transform spectrometer; interferometry AB A new high spectral resolution (0.25 cm(-1)) and high spatial resolution (2.6 km) scanning (46 km swath width) Fourier Transform Spectrometer (FTS) has been built for flight on NASA high altitude (similar to 20 km) aircraft. The instrument, called the NPOESS Aircraft Sounding Testbed-Interferometer (NAST-I), has been flown during several field campaigns to provide experimental observations needed to finalize specifications and to test proposed designs for future satellite instruments; specifically, the Cross-track Infrared Sounder (CrIS) to fly on the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NAST-I provides new and exciting observations of mesoscale structure of the atmosphere, including the fine scale thermodynamic characteristics of hurricanes. The NAST-I instrument is described, its excellent spectral and radiometric performance is demonstrated, and surface and atmospheric remote sensing results obtained during airborne measurement campaigns are presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, W (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. RI Li, Jun/H-3579-2015 OI Li, Jun/0000-0001-5504-9627 NR 5 TC 25 Z9 25 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 0-8194-3242-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3756 BP 2 EP 8 DI 10.1117/12.366362 PG 7 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BN97T UT WOS:000083736000001 ER PT S AU Refaat, TF Luck, WS De Young, RJ AF Refaat, TF Luck, WS De Young, RJ BE Larar, AM TI An advanced water vapor lidar detection system for aircraft and space deployment SO OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE atmospheric water vapor; lidar; DIAL; LASE; detection system; APD AB An advanced compact differential absorption lidar detection system for atmospheric water vapor measurement is reported. This system interfaces the lidar receiver telescope to a personal computer and contains an advanced avalanche photodiode detector, signal conditioning circuit, 14-bit 10 MHz digitizer and a microcontroller. The whole system was realized on one electronic card. Characterization results indicate low noise with reduced size, reduced mass and an extended measurement range over current lidar detection systems. The new system can be incorporated in spacecraft lidar systems. Simulated lidar return measurements were performed with the new system in order to obtain its minimum detectable signal limits. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP De Young, RJ (reprint author), NASA, Langley Res Ctr, MS 401A, Hampton, VA 23681 USA. NR 9 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 0-8194-3242-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3756 BP 92 EP 99 DI 10.1117/12.366419 PG 8 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BN97T UT WOS:000083736000009 ER PT S AU Chu, WP Mauldin, LE AF Chu, WP Mauldin, LE BE Larar, AM TI Overview of the SAGE III Experiment SO OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE remote sensing; space-borne instrument; aerosols; ozone; environmental monitoring; climate monitoring ID STRATOSPHERIC AEROSOL; INVERSION AB The Stratospheric Aerosol and gas Experiment III (SAGE III) is part of the NASA EOS program designed for long term monitoring of atmospheric ozone and aerosol, together with other atmospheric species important to the study of global change. SAGE III is an advanced version of the previous occultation instruments such as SAM II, SAGE I, and SAGE II which have provided long term data on aerosol and ozone for the last twenty years. SAGE III will continue these long term measurements well into the first decade of the 21st century. SAGE LII will measure profiles of aerosols, ozone, water vapor, nitrogen dioxide, temperature, pressure, chlorine dioxide, and nitrogen trioxide using the solar and lunar occultation techniques. Currently two SAGE III instruments will be launched between 1999 and 2003. The First SAGE III will be on a Russian Meteor 3M spacecraft to be launched in the Fall of 1999. The second SAGE III will be on the Space Station in 2003. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Chu, WP (reprint author), NASA, Langley Res Ctr, MS 475, Hampton, VA 23681 USA. NR 11 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 0-8194-3242-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3756 BP 102 EP 109 DI 10.1117/12.366363 PG 8 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BN97T UT WOS:000083736000010 ER PT S AU Veiga, RE AF Veiga, RE BE Larar, AM TI Preflight characterization of the SAGE III instrument SO OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research CY JUL 19-21, 1999 CL DENVER, CO SP SPIE AB The SAGE III instrument design, and sampling modes are presented. The central focus will be on the instrument test data useful for characterization and their relevance to processing algorithms. The following effects will be discussed: spectrometer stray light and Sine spread'; CCD substrate scattering into the readout registers; dark current; charge transfer efficiency; wavelength calibration; and etaloning Test data from Sun/Moon-Look testing from all three instruments will be presented. C1 NASA, Langley Res Ctr, Sci Applicat Int Corp, Hampton, VA 23861 USA. RP Veiga, RE (reprint author), NASA, Langley Res Ctr, Sci Applicat Int Corp, MS 475, Hampton, VA 23861 USA. NR 2 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 0-8194-3242-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3756 BP 110 EP 120 DI 10.1117/12.366364 PG 11 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BN97T UT WOS:000083736000011 ER PT S AU Moore, AS Cisewski, MS Roell, MM Rawls, JR Veiga, RE Borchardt, RP Graves, SS Hayhurst, AR Hickman, JC Holloway, SE Mauldin, LE Tutterow, RD AF Moore, AS Cisewski, MS Roell, MM Rawls, JR Veiga, RE Borchardt, RP Graves, SS Hayhurst, AR Hickman, JC Holloway, SE Mauldin, LE Tutterow, RD BE Larar, AM TI Direct solar and lunar viewing ground testing to simulate earth orbit scenarios with the Stratospheric Aerosol and Gas Experiment III (SAGE-III) space instrument SO OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE remote sensing; aerosols; ozone; SAGE-III; stratosphere; global coverage; testing; solar scan AB The instrument description and ground test simulations of on-orbit scenarios for the Stratospheric Aerosol and Gas Experiment III (SAGE-III) are presented. SAGE-III is a spectrographic instrument that has been developed in the U.S. and will orbit aboard a Russian Meteor-3M spacecraft beginning Fail of 1999. It will orbit at a nominal altitude of 1020 km and inclination of 99.6 degrees for global coverage. The instrument will measure the attenuated solar and lunar radiation from 290 nm to 1550 nm wavelength range through the stratosphere. The radiant data are normalized to the non-attenuated radiation measured above the atmosphere during each occultation event. The data are used to calculate the vertical distribution of stratospheric aerosols, ozone and other species that are critical in studying trends and global change. After on-orbit operations begin, the autonomy of the instrument will not need up-link commands to acquire science data or to transmit the data back to the United States and Russia. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Moore, AS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 3 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 0-8194-3242-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3756 BP 121 EP 128 PG 8 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BN97T UT WOS:000083736000012 ER PT S AU Szatkowski, LS Bradley, OH Mauldin, LE Wusk, MB Chu, WP Farwell, LC Galeone, P AF Szatkowski, LS Bradley, OH Mauldin, LE Wusk, MB Chu, WP Farwell, LC Galeone, P BE Larar, AM TI The stratospheric aerosol and gas experiment III (SAGE III) mission aboard the International Space Station SO OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE SAGE; International Space Station; EXPRESS; lunar occultation; solar occultation; spectrometer; aerosols; ozone; atmospheric science; attached payload AB This paper presents the SAGE III mission for the International Space Station. SAGE III is fifth in a series of instruments developed to monitor aerosols and gaseous constituents in the stratosphere and troposphere. Three instruments are being developed by the National Aeronautics and Space Administration (NASA) Langley Research Center for the Earth Science Enterprise: one for a high-inclined orbit aboard the Russian Meteor-3M (M3M) spacecraft; one for a mid-inclined (51.6 deg) orbit on the International Space Station, the subject of this paper, and a third for a potential flight of opportunity (FOO) mission. The SAGE III/ISS payload is comprised of international components: a pointing platform called the Hexapod, provided by the European Space Agency and the Expedite the Processing of Experiments to International Space Station (ISS) (EXPRESS) pallet adapter, (part of a carrier system to be built by Brazil for NASA. The SAGE III/ISS mission is manifested for a launch on the ISS Utilization Flight (UF) 3, currently scheduled to launch February 2003. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Szatkowski, LS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 2 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 0-8194-3242-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3756 BP 164 EP 171 DI 10.1117/12.366370 PG 8 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BN97T UT WOS:000083736000017 ER PT S AU Halama, GE McAdoo, J Jhabvala, M Ewin, A Fortin, M Bredthauer, R Abedin, N AF Halama, GE McAdoo, J Jhabvala, M Ewin, A Fortin, M Bredthauer, R Abedin, N BE Larar, AM TI SAGE III alternative detector design and characterization SO OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE CCD; photodiode; grating; spectrometer; interlined; near-infrared; solar; occultation; ultraviolet; SAGE III AB The Stratospheric Aerosol and Gas Experiment (SAGE) III requires a detector that provides spectral coverage from 280 - 1050 nm. In order to achieve higher responsivity at the ultra-violet wavelengths a backside-thinned silicon CCD technology was chosen. For strength, the backside-thinned detector was bonded to a soda glass substrate. The device thinness allowed the long near infrared wavelengths to pass through the silicon, scatter off the soda glass, and cause cross talk into nearby pixels. Reflections from the soda glass caused etalon-like effects and gave the thinned CCD a highly temperature dependent response. These difficulties led the project manager to examine different options for a replacement detector. Photodiode/CCD technology based on the Moderate-Resolution Imaging Spectrometer-Tilt (MODIS-T) and Gas and Aerosol Monitoring Sensorcraft (GAMS) detectors systems was combined and used to design and fabricate a backup detector far the SAGE III program. The device design and characterization are presented. The design focused on elimination of the scattering due to the soda glass and the temperature dependent etalon effect, increasing charge storage capacity. The detector was designed to allow a retrofit with the existing SAGE III spectrometer. The primary disadvantage of the new detector is its loss of responsivity at the shorter wavelengths. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Halama, GE (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 4 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 0-8194-3242-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3756 BP 172 EP 189 DI 10.1117/12.366372 PG 18 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BN97T UT WOS:000083736000018 ER PT S AU Larar, AM Roettker, WA Puschell, JJ Cook, WB AF Larar, AM Roettker, WA Puschell, JJ Cook, WB BE Larar, AM TI Fabry-Perot interferometer for geostationary-based observations of tropospheric ozone SO OPTICAL SPECTROSCOPIC TECHNIQUES AND INSTRUMENTATION FOR ATMOSPHERIC AND SPACE RESEARCH III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research CY JUL 19-21, 1999 CL DENVER, CO SP SPIE DE Fabry-Perot interferometry; geostationary observations; tropospheric chemistry; tropospheric ozone AB Monitoring tropospheric chemistry from space is the next frontier for advancing present-day remote sensing capabilities to meet future high-priority atmospheric science measurement needs. Paramount to these measurement requirements is that for tropospheric ozone, one of the most important gas-phase trace constituents in the lower atmosphere. Such space-based observations of tropospheric trace species are challenged by the need for sufficient horizontal resolution to identify constituent spatial distribution inhomogeneities (that result from non-uniform sources/sinks and atmospheric transport) and the need for adequate temporal resolution to resolve daytime and diurnal variations. Both of these requirements can be fulfilled from a geostationary Earth orbit(GEO) measurement configuration. An advanced atmospheric remote sensing concept for the measurement of tropospheric ozone from a GEO-based platform is presented. The concept is centered about an imaging Fabry-Perot interferometer (FPI) observing a narrow spectral interval within the strong 9.6 micron ozone infrared band with a spectral resolution similar to 0.07 cm(-1). This concept could also simplify other atmospheric chemistry sensor designs (which typically require spectral resolutions in the range of 0.01 - 0.1 cm(-1)), since such an FPI approach could be implemented for those spectral bands requiring the highest spectral resolution and thus simplify overall design complexity. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Larar, AM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 11 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 0-8194-3242-3 J9 P SOC PHOTO-OPT INS PY 1999 VL 3756 BP 192 EP 201 DI 10.1117/12.366373 PG 10 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BN97T UT WOS:000083736000019 ER PT S AU Kim, Q Cunningham, TJ Pain, B Lange, MJ Olsen, GH AF Kim, Q Cunningham, TJ Pain, B Lange, MJ Olsen, GH BE Feldman, MR Grote, JG HibbsBrenner, MK TI Characteristics of monolithically integrated InGaAs active pixel imager array SO OPTOELETRONIC INTEGRATED CIRCUITS AND PACKAGING III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optoelectronic Integrated Circuits and Packaging III CY JAN 28-29, 1999 CL SAN JOSE, CA SP SPIE, Def Adv Res Projects Agnecy DE dual (Visible/IR) responses; active pixel sensor (APS); InGaAs; InP imaging detector ID FET AB Switching and amplifying characteristics of a newly developed monolithic InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate. It consists of an InGaAs photodiode connected to InP depletion-mode junction field effect transistors (JFETs) for low leakage, low power, and fast control of circuit signal amplifying, buffering, selection, and reset. This monolithically integrated active pixel sensor configuration eliminates the need for hybridization with silicon multiplexer. In addition, the configuration allows the sensor to be front illuminated, making it sensitive to visible as well as near infrared signal radiation. Adapting the existing 1.55 mu m fiber optical communication technology, this integration will be an ideal system of optoelectronic integration for dual band (Visible/IR) applications near room temperature, for use in atmospheric gas sensing in space, and for target identification on earth. In this paper, two different types of small 4x1 test arrays will be described. The effectiveness of switching and amplifying circuits will be discussed in terms of circuit effectiveness (leakage, operating frequency, and temperature) in preparation for the second phase demonstration of integrated, two-dimensional monolithic InGaAs active pixel sensor arrays for applications in transportable shipboard surveillance, night vision, and emission spectroscopy. 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, Pasadena, CA 91109 USA. NR 6 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 0-8194-3101-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3631 BP 122 EP 130 DI 10.1117/12.348303 PG 3 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BN09U UT WOS:000080681700015 ER PT S AU Kuhn, JL Benner, SM Butler, CD Silk, EA AF Kuhn, JL Benner, SM Butler, CD Silk, EA BE Derby, EA Gordon, CG Vukobratovich, D Yoder, PR Zweben, C TI Thermal and mechanical performance of a carbon/carbon composite spacecraft radiator SO OPTOMECHANICAL ENGINEERING AND VIBRATION CONTROL SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optomechanical Engineering and Vibration Control CY JUL 20-23, 1999 CL DENVER, CO SP SPIE DE spacecraft radiator; carbon-carbon composite; thermal/vacuum testing; vibration testing; thermal modeling; structural modeling; EO-1; and performance AB Carbon-carbon composite materials offer greater thermal efficiency, stiffness to weight ratio, tailorability, and dimensional stability than aluminum. These lightweight thermal materials could significantly reduce the overall costs associated with satellite thermal control and weight. However, the high cost and long lead-time for carbon-carbon manufacture have limited their widespread usage. Consequently, an informal partnership between government and industrial personnel called the Carbon-Carbon Spacecraft Radiator Partnership (CSRP) was created to foster carbon-carbon composite use for thermally and structurally demanding space radiator applications. The first CSRP flight opportunity is on the New Millennium Program (NMP) Earth Orbiter-1 (EO-1) spacecraft, scheduled for launch in late 1999. For EO-1, the CSRP designed and fabricated a Carbon-Carbon Radiator (CCR) with carbon-carbon facesheets and aluminum honeycomb core, which will also serve as a structural shear panel. While carbon-carbon is an ideal thermal candidate for spacecraft radiators, in practice there are technical challenges that may compromise performance. In this work, the thermal and mechanical performance of the EO-1 CCR is assessed by analysis and testing. Both thermal and mechanical analyses were conducted to predict the radiator response to anticipated launch and on-orbit loads. The thermal model developed was based on thermal balance test conditions. The thermal analysis was performed using SINDA version 4.0. Structural finite element modeling and analysis were performed using SDRC/I-DEAS and UAI/NASTRAN, respectively. In addition, the CCR was subjected to flight qualification thermal/vacuum and vibration tests. The panel meets or exceeds the requirements for space flight and demonstrates promise for future satellite missions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kuhn, JL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 5 TC 1 Z9 1 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 0-8194-3272-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3786 BP 162 EP 178 DI 10.1117/12.363792 PG 17 WC Acoustics; Engineering, Mechanical; Instruments & Instrumentation; Materials Science, Composites; Optics SC Acoustics; Engineering; Instruments & Instrumentation; Materials Science; Optics GA BN92H UT WOS:000083488000016 ER PT S AU Willis, PB Dyer, J Dummer, S AF Willis, PB Dyer, J Dummer, S BE Derby, EA Gordon, CG Vukobratovich, D Yoder, PR Zweben, C TI Fabrication and thermo-optical properties of the MLS composite primary reflector SO OPTOMECHANICAL ENGINEERING AND VIBRATION CONTROL SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optomechanical Engineering and Vibration Control CY JUL 20-23, 1999 CL DENVER, CO SP SPIE DE EOS; MLS; composites; reflectors; microwaves; coatings; silicon suboxide; ozone AB The Microwave Limb Sounder (MLS) is a limb-sounding radiometer sensing emissions in the millimeter and sub-millimeter range. MLS will contribute to an understanding of atmospheric chemistry by assessing stratospheric and tropospheric ozone depletion, climate forcings and volcanic effects. The heart of the antenna is the primary reflector, constructed from graphite/cyanate composites in a facesheet/core construction. The reflector has an aperture of one square meter, a mass of 8.7 kilos and final figure accuracy of 4.37 microns rms. The surface is also modified to ensure RF reflectivity, prevent solar concentration and provide thermal balance to the spacecraft. The surface is prepared by precision bead-blasting then coated with vapor deposited aluminum (VDA) and finally a layer of silicon suboxide (SiOx) to control the infrared emissivity. The resulting surface has a solar absorptance of 0.43 and an absorptance/emittance ratio of 1.3. BRDF analysis shows that 93% of the incident thermal energy is reflected outside a 10 degree angle of cone. For its mass and aperture, we believe this reflector to have the highest figure accuracy yet achieved in a composite antenna construction. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Willis, PB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 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 0-8194-3272-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3786 BP 200 EP 205 DI 10.1117/12.363796 PG 6 WC Acoustics; Engineering, Mechanical; Instruments & Instrumentation; Materials Science, Composites; Optics SC Acoustics; Engineering; Instruments & Instrumentation; Materials Science; Optics GA BN92H UT WOS:000083488000019 ER PT S AU Ford, VG White, ML Hochberg, E McGown, J AF Ford, VG White, ML Hochberg, E McGown, J BE Derby, EA Gordon, CG Vukobratovich, D Yoder, PR Zweben, C TI Optomechanical design of nine cameras for the earth observing system multi-angle imaging spectro-radiometer, TERRA platform SO OPTOMECHANICAL ENGINEERING AND VIBRATION CONTROL SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optomechanical Engineering and Vibration Control CY JUL 20-23, 1999 CL DENVER, CO SP SPIE DE optomechanical; refractive lens; passive thermal compensation; lens positioning; MISR; lens centering AB The Multi-Angle Imaging Spectro-Radiometer (MISR) is a push-broom instrument using nine cameras to collect data at nine different angles through the atmosphere. The science goals are to monitor global atmospheric particulates, cloud movements, and vegetative changes. The camera optomechanical requirements were: to operate within specification over a temperature range of 0C to 10C; to survive a temperature range of -40C to 80C; to survive launch loads and on-orbit radiation; to be non-contaminating both to itself and to other instruments; and to remained aligned though the mission. Each camera has its own lens, detector, and thermal control. The lenses are refractive; thus passive thermal focus compensation and maintaining lens positioning and centering were dominant issues. Because of the number of cameras, modularity was stressed in the design. This paper will describe the final design of the cameras, the driving design considerations, and the results of qualification testing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Ford, VG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 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 0-8194-3272-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3786 BP 264 EP 272 DI 10.1117/12.363804 PG 9 WC Acoustics; Engineering, Mechanical; Instruments & Instrumentation; Materials Science, Composites; Optics SC Acoustics; Engineering; Instruments & Instrumentation; Materials Science; Optics GA BN92H UT WOS:000083488000026 ER PT J AU Teece, MA Fogel, ML Dollhopf, ME Nealson, KH AF Teece, MA Fogel, ML Dollhopf, ME Nealson, KH TI Isotopic fractionation associated with biosynthesis of fatty acids by a marine bacterium under oxic and anoxic conditions SO ORGANIC GEOCHEMISTRY LA English DT Article DE bacteria; Shewanella putrefaciens; serine pathway; isotope fractionation; fatty acids; compound specific isotope analysis ID SEDIMENTARY ORGANIC-MATTER; STABLE CARBON-ISOTOPE; BLACK-SEA; SHEWANELLA-PUTREFACIENS; FACULTATIVE ANAEROBE; MOLECULAR EVIDENCE; REDUCING BACTERIA; LIPID-COMPOSITION; DIVERSE ORIGINS; WATER COLUMN AB Shewanella putrefaciens (Strain MR-4), a gram negative facultative marine bacterium, was grown to stationary phase under both aerobic and anaerobic conditions using lactate as the sole carbon source. Aerobically-produced cells were slightly enriched in C-13 (+ 1.5 parts per thousand) relative to the lactate carbon source, whereas those from anaerobic growth were depleted in C-13 (-2.2 parts per thousand). The distribution of fatty acids produced under aerobic conditions was similar to that resulting from anaerobic growth, being dominated by C-16:1 omega 7 and C-16:0 fatty acids with a lesser amount of the C-18:1 omega 7 component. Low concentrations of saturated even numbered normal fatty acids in the C-14 to C-18 range, and iso-C-15:0 were synthesized under both conditions. Fatty acids from anaerobic cultures (average delta(13)C = -37.8 parts per thousand) were considerably depleted in C-13 relative to their aerobically-synthesized counterparts (-28.8 parts per thousand). The distinct differences in isotopic composition of both whole cells and individual fatty acid components result from differences in assimilation pathways. Under aerobic conditions, the primary route of assimilation involves the pyruvate dehydrogenase enzyme complex which produces acetyl-CoA, the precursor to lipid synthesis. In contrast, under anaerobic conditions formate, and not acetate, is the central intermediate in carbon assimilation with the precursors to fatty acid synthesis being produced via the serine pathway. Anaerobically-produced bacterial fatty acids were depleted by up to 12 parts per thousand relative to the carbon source. Therefore, detection of isotopically depleted fatty acids in sediments may be falsely attributed to a terrestrial origin, when in fact they are the result of bacterial resynthesis. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. Univ Wisconsin, Ctr Great Lakes Studies, Milwaukee, WI 53204 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Teece, MA (reprint author), Carnegie Inst Washington, Geophys Lab, 5251 Broad Branch Rd NW, Washington, DC 20015 USA. RI Fogel, Marilyn/M-2395-2015 OI Fogel, Marilyn/0000-0002-1176-3818 NR 54 TC 81 Z9 85 U1 8 U2 23 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0146-6380 J9 ORG GEOCHEM JI Org. Geochem. PY 1999 VL 30 IS 12 BP 1571 EP 1579 DI 10.1016/S0146-6380(99)00108-4 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 266ME UT WOS:000084303100010 ER PT J AU Summers, DP AF Summers, DP TI Sources and sinks for ammonia and nitrite on the early earth and the reaction of nitrite with ammonia SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article ID AQUEOUS-SOLUTION; CARBON-DIOXIDE; ATMOSPHERE; EVOLUTION; NITROGEN; REDUCTION; FIXATION; IMPACTS; SYSTEMS; OXYGEN AB An analysis of sources and sinks for ammonia and nitrite on the early Earth was conducted. Rates of formation and destruction, and steady state concentrations of both species were determined by steady state kinetics. The importance of the reaction of nitrite with ammonia on the feasibility of ammonia formation from nitrite was evaluated. The analysis considered conditions such as temperature, ferrous iron concentration, and pH. For sinks we considered the reduction of nitrite to ammonia, reaction between nitrite and ammonia, photochemical destruction of both species, and destruction at hydrothermal vents. Under most environmental conditions, the primary sink for nitrite is reduction to ammonia. The reaction between ammonia and nitrite is not an important sink for either nitrite or ammonia. Destruction at hydrothermal vents is important at acidic pH's and at low ferrous iron concentrations. Photochemical destruction, even in a worst case scenario, is unimportant under many conditions except possibly under acidic, low iron concentration, or low temperature conditions. The primary sink for ammonia is photochemical destruction in the atmosphere. Under acidic conditions, more of the ammonia is tied up as ammonium (reducing its vapor pressure and keeping it in solution) and hydrothermal destruction becomes more important. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Summers, DP (reprint author), NASA, Ames Res Ctr, SETI Inst, M-S 239-4, Moffett Field, CA 94035 USA. NR 31 TC 24 Z9 24 U1 0 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PD JAN PY 1999 VL 29 IS 1 BP 33 EP 46 DI 10.1023/A:1006517823004 PG 14 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 173KG UT WOS:000078979300003 PM 10077867 ER PT J AU Quinn, RC Zent, AP AF Quinn, RC Zent, AP TI Peroxide-modified titanium dioxide: A chemical analog of putative Martian soil oxidants SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article ID HYDROXYLATED TIO2 SURFACES; VIKING BIOLOGY EXPERIMENTS; LIFE DETECTION EXPERIMENT; PHOTO-ADSORPTION; MARS; DESORPTION; SEARCH; OXYGEN; MODEL AB Hydrogen peroxide chemisorbed on titanium dioxide (peroxide-modified titanium dioxide) is investigated as a chemical analog to the putative soil oxidants responsible for the chemical reactivity seen in the Viking biology experiments. When peroxide-modified titanium dioxide (anatase) was exposed to a solution similar to the Viking labeled release (LR) experiment organic medium, CO2 gas was released into the sample cell headspace. Storage of these samples at 10 degrees C for 48 hr prior to exposure to organics resulted in a positive response while storage for 7 days did not. In the Viking LR experiment, storage of the Martian surface samples for 2 sols (similar to 49 hr) resulted in a positive response while storage for 141 sols essentially eliminated the initial rapid release of CO2. Heating the peroxide-modified titanium dioxide to 50 degrees C prior to exposure to organics resulted in a negative response. This is similar to, but not identical to, the Viking samples where heating to approximately 46 degrees C diminished the response by 54-80% and heating to 51.5 apparently eliminated the response. When exposed to water vapor, the peroxide-modified titanium dioxide samples release O-2 in a manner similar to the release seen in the Viking gas exchange experiment (GEx). Reactivity is retained upon heating at 50 degrees C for three hours, distinguishing this active agent from the one responsible for the release of CO2 from aqueous organics. The release of CO2 by the peroxide-modified titanium dioxide is attributed to the decomposition of organics by outer-sphere peroxide complexes associated with surface hydroxyl groups, while the release of O-2 upon humidification is attributed to more stable inner-sphere peroxide complexes associated with Ti4+ cations. Heating the peroxide-modified titanium dioxide to 145 degrees C inhibited the release of O-2, while in the Viking experiments heating to this temperature diminished but did not eliminated the response. Although the thermal stability of the titanium-peroxide complexes in this work is lower than the stability seen in the Viking experiments, it is expected that similar types of complexes will form in titanium containing minerals other than anatase and the stability of these complexes will vary with surface hydroxylation and mineralogy. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Quinn, RC (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 239-14, Moffett Field, CA 94035 USA. NR 28 TC 45 Z9 46 U1 3 U2 18 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PD JAN PY 1999 VL 29 IS 1 BP 59 EP 72 DI 10.1023/A:1006506022182 PG 14 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 173KG UT WOS:000078979300005 PM 10077869 ER PT J AU Baskaran, S Ramachandran, N Noever, D AF Baskaran, S Ramachandran, N Noever, D TI Probabilistic and other neural nets in multi-hole probe calibration and flow angularity pattern recognition SO PATTERN ANALYSIS AND APPLICATIONS LA English DT Article DE calibration wind tunnel; fluid dynamics; multi-hole probes; numerical simulation; probabilistic neural nets ID NETWORK AB The use of probabilistic (PNN) and multilayer feedforward (MLFNN) neural networks is investigated for the calibration of multi-hole pressure probes and the prediction of associated flow angularity patterns in test flow fields. Both types of network are studied in detail for their calibration and prediction characteristics. The current formalism can be applied to any multi hole probe, however the test results for the most commonly used five-hole Cone and Prism probe types alone are reported in this paper. C1 Raytheon Co, STX MSFC NASA E576, Huntsville, AL 35812 USA. Univ Vienna, Inst Theoret Chem, Vienna, Austria. NASA, Univ Space Res Assoc, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Baskaran, S (reprint author), Raytheon Co, STX MSFC NASA E576, Huntsville, AL 35812 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1433-7541 J9 PATTERN ANAL APPL JI Pattern Anal. Appl. PY 1999 VL 2 IS 1 BP 92 EP 98 DI 10.1007/s100440050018 PG 7 WC Computer Science, Artificial Intelligence SC Computer Science GA 256CG UT WOS:000083707600011 ER PT J AU Goshtasby, AA Le Moigne, J AF Goshtasby, AA Le Moigne, J TI Image registration - Guest editors' introduction SO PATTERN RECOGNITION LA English DT Editorial Material C1 Wright State Univ, Dept Comp Sci & Engn, Dayton, OH 45435 USA. NASA, Goddard Space Flight Ctr, CESDIS, USRA, Greenbelt, MD 20771 USA. RP Goshtasby, AA (reprint author), Wright State Univ, Dept Comp Sci & Engn, Dayton, OH 45435 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0031-3203 J9 PATTERN RECOGN JI Pattern Recognit. PD JAN PY 1999 VL 32 IS 1 BP 1 EP 2 PG 2 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 161PP UT WOS:000078298000001 ER PT J AU Mount, DM Netanyahu, NS Le Moigne, J AF Mount, DM Netanyahu, NS Le Moigne, J TI Efficient algorithms for robust feature matching SO PATTERN RECOGNITION LA English DT Article; Proceedings Paper CT CESDIS Image Registration Workshop CY 1997 CL GREENBELT, MARYLAND SP NASA Goddard Space Flight Ctr DE image registration; point pattern matching; Hausdorff distance; approximation algorithms ID IMAGE REGISTRATION; HAUSDORFF DISTANCE; POINT; CONGRUENCE; OBJECTS AB One of the basic building blocks in any point-based registration scheme involves matching feature points that are extracted from a sensed image to their counterparts in a reference image. This leads to the fundamental problem of point matching: Given two sets of points, find the (affine) transformation that transforms one point set so that its distance from the other point set is minimized. Because of measurement errors and the presence of outlying data points, it is important that the distance measure between the two point sets be robust to these effects. We measure distances using the partial Hausdorff distance. Point matching can be a computationally intensive task, and a number of theoretical and applied approaches have been proposed for solving this problem. In this paper, we present two algorithmic approaches to the point matching problem, in an attempt to reduce its computational complexity, while still providing a guarantee of the quality of the final match. Our first method is an approximation algorithm, which is loosely based on a branch-and-bound approach due to Huttenlocher and Rucklidge, (Technical Report 1321, Dept. of Computer Science, Cornell University, Ithaca, 1992; Proc. IEEE Conf. on Computer vision and Pattern Recognition, New York, 1993, pp. 705-706). We show that by varying the approximation error bounds, it is possible to achieve a tradeoff between the quality of the match and the running time of the algorithm. Our second method involves a Monte Carlo method for accelerating the search process used in the first algorithm. This algorithm operates within the framework of a branch-and-bound procedure, but employs point-to-point alignments to accelerate the search. We show that this combination retains many of the strengths of branch-and-bound search, but provides significantly faster search times by exploiting alignments. With high probability, this method succeeds in finding an approximately optimal match. We demonstrate the algorithms' performances on both synthetically generated data points and actual satellite images. (C) 1999 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Div Space Data & Comp, Univ Space Res Assoc,CESDIS, Greenbelt, MD 20771 USA. Univ Maryland, Ctr Automat Res, College Pk, MD 20742 USA. Univ Maryland, Dept Comp Sci, College Pk, MD 20742 USA. Univ Maryland, Inst Adv Comp Studies, College Pk, MD 20742 USA. RP Netanyahu, NS (reprint author), NASA, Goddard Space Flight Ctr, Div Space Data & Comp, Univ Space Res Assoc,CESDIS, Code 930-5, Greenbelt, MD 20771 USA. NR 37 TC 83 Z9 91 U1 2 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0031-3203 J9 PATTERN RECOGN JI Pattern Recognit. PD JAN PY 1999 VL 32 IS 1 BP 17 EP 38 DI 10.1016/S0031-3203(98)00086-7 PG 22 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 161PP UT WOS:000078298000003 ER PT J AU Watson, AB Hu, J AF Watson, A. B. Hu, J. TI ShowTime: A QuickTime-based infrastructure for vision research displays SO PERCEPTION LA English DT Meeting Abstract C1 [Watson, A. B.] NASA, Vis Grp, Ames Res Ctr, Moffett Field, CA 94035 USA. [Hu, J.] Raytheon Corp, Waltham, MA USA. EM abwatson@mail.arc.nasa.gov NR 0 TC 4 Z9 4 U1 0 U2 1 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1999 VL 28 SU S BP 45 EP 45 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AQ UT WOS:000207910500141 ER PT J AU Eckstein, MP Beutter, BR Stone, LS AF Eckstein, M. P. Beutter, B. R. Stone, L. S. TI Human saccades in search: second chances are worth a second peak SO PERCEPTION LA English DT Meeting Abstract C1 [Eckstein, M. P.] Cedars Sinai Med Ctr, Los Angeles, CA 90048 USA. [Beutter, B. R.; Stone, L. S.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM miguel@medphysics.csmcs.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1999 VL 28 SU S BP 111 EP 111 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AQ UT WOS:000207910500352 ER PT J AU Chukova, SV Ahumada, AJ Vershinina, EA AF Chukova, S. V. Ahumada, A. J., Jr. Vershinina, E. A. TI Prior stimuli affect both size threshold and decision time SO PERCEPTION LA English DT Meeting Abstract C1 [Chukova, S. V.; Vershinina, E. A.] Russian Acad Sci, IP Pavlov Physiol Inst, Vis Physiol Lab, St Petersburg 199034, Russia. [Ahumada, A. J., Jr.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM svch@infran.ru NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1999 VL 28 SU S BP 145 EP 145 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AQ UT WOS:000207910500468 ER PT J AU Neveu, C AF Neveu, C. TI Formal models of blur detection SO PERCEPTION LA English DT Meeting Abstract C1 [Neveu, C.] NASA, Ames Res Ctr, Auton & Robot Grp, Moffett Field, CA 94035 USA. EM neveu@artemis.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1999 VL 28 SU S BP 147 EP 147 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AQ UT WOS:000207910500474 ER PT J AU Watson, AB Hu, J AF Watson, A. B. Hu, J. TI Show Time: A Quick Time-based infrastructure for vision research displays SO PERCEPTION LA English DT Meeting Abstract C1 [Watson, A. B.] NASA, Ames Res Ctr, Vis Grp, Moffett Field, CA 94035 USA. [Hu, J.] Raytheon Corp, Waltham, MA USA. EM abwatson@mail.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1999 VL 28 SU S BP 147 EP 147 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AQ UT WOS:000207910500473 ER PT J AU Quattrochi, DA Atkinson, PM AF Quattrochi, DA Atkinson, PM TI Introduction to this special issue on Geostatistics and Scaling of Remote Sensing and Spatial Data SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Editorial Material C1 NASA, George C Marshall Space Flight Ctr, Global Hydrol & Climate Ctr, Huntsville, AL 35812 USA. Univ Southampton, Dept Geog, Southampton SO17 1BJ, Hants, England. RP Quattrochi, DA (reprint author), NASA, George C Marshall Space Flight Ctr, Global Hydrol & Climate Ctr, HR20, Huntsville, AL 35812 USA. RI Atkinson, Peter/L-9508-2013 NR 0 TC 2 Z9 2 U1 1 U2 5 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JAN PY 1999 VL 65 IS 1 BP 40 EP 40 PG 1 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 152NW UT WOS:000077784500004 ER PT J AU Emerson, CW Lam, NSN Quattrochi, DA AF Emerson, CW Lam, NSN Quattrochi, DA TI Multi-scale fractal analysis of image texture and pattern SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article; Proceedings Paper CT Annual Meeting of the Association-of-American-Geographers CY MAR 25-29, 1998 CL BOSTON, MASSACHUSETTS SP Assoc Amer Geographers ID REMOTE-SENSING DATA; TOPOGRAPHIC SURFACES; RESOLUTION AB Analyses of the fractal dimension of Normalized Difference Vegetation Index (NDVI) images of homogeneous laud covers near Huntsville, Alabama revealed that the fractal dimension of an image of an agricultural land cover indicates greater complexity as pixel size increases, a forested land cover gradually grows smoother, and an urban image remains roughly self-similar over the range of pixel sizes analyzed (10 to 80 meters). A similar analysis of Landsat Thematic Mapper images of the East Humboldt Range in Nevada taken four months apart show a more complex relation between pixel size and fractal dimension. The major visible difference between the spring and late summer NDVI images is the absence of high elevation snow cover in the summer image. This change significantly alters the relation between fractal dimension and pixel size. The slope of the fractal dimension-resolution relation provides indications of how image classification or feature identification will be affected by changes in sensor spatial resolution. C1 SW Missouri State Univ, Dept Geog Geol & Planning, Springfield, MO 65804 USA. Louisiana State Univ, Dept Geog & Anthropol, Baton Rouge, LA 70803 USA. NASA, George C Marshall Space Flight Ctr, Global Hydrol & Climate Ctr, Huntsville, AL 35812 USA. RP Emerson, CW (reprint author), SW Missouri State Univ, Dept Geog Geol & Planning, Springfield, MO 65804 USA. EM cwe836f@mail.smsu.edu NR 27 TC 69 Z9 70 U1 0 U2 13 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JAN PY 1999 VL 65 IS 1 BP 51 EP 61 PG 11 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 152NW UT WOS:000077784500006 ER PT J AU Qiu, HL Lam, NSN Quattrochi, DA Gamon, JA AF Qiu, HL Lam, NSN Quattrochi, DA Gamon, JA TI Fractal characterization of hyperspectral imagery SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article; Proceedings Paper CT Annual Meeting of the Association-of-American-Geographers CY MAR 25-29, 1998 CL BOSTON, MASSACHUSETTS SP Assoc Amer Geographers ID DIMENSION AB Two AVIRIS hyperspectral images selected from the Los Angeles area, one representing urban and the other rural, were used to examine their spatial complexity across their entire spectrum of the remote sensing data. Using the ICAMS (Image Characterization And Modeling System) software, we computed the fractal dimension values using the isarithm and triangular prism methods for all 224 bands in the two AVIRIS scenes. The resultant fractal dimensions reflect changes in image complexity across the spectral range of the hyperspectral images. Both the isarithm and triangular prism methods detect unusually high D values on the spectral bands that fall within the atmospheric absorption and scattering zones where signal-to-noise ratios are low. Fractal dimensions for the urban area resulted in higher values than for the rural landscape, and the differences between the resulting D values are more distinct in the visible bands. The triangular prism method is sensitive to a few random speckles in the images, leading to a lower dimensionality. On the contrary the isarithm method will ignore the speckles and focus on the major variation dominating the surface, thus resulting in a higher dimension. It is seen where the fractal curves plotted for the entire bandwidth range of the hyperspectral images could be used to distinguish landscape types as well as for screening noisy bands. C1 Calif State Univ Los Angeles, Dept Geog & Urban Anal, Los Angeles, CA 90032 USA. Louisiana State Univ, Dept Geog & Anthropol, Baton Rouge, LA 70803 USA. NASA, Global Hydrol & Climate Ctr, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Calif State Univ Los Angeles, Dept Biol & Microbiol, Los Angeles, CA 90032 USA. RP Qiu, HL (reprint author), Calif State Univ Los Angeles, Dept Geog & Urban Anal, Los Angeles, CA 90032 USA. RI Gamon, John/A-2641-2014 OI Gamon, John/0000-0002-8269-7723 NR 17 TC 33 Z9 38 U1 0 U2 4 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JAN PY 1999 VL 65 IS 1 BP 63 EP 71 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 152NW UT WOS:000077784500007 ER PT B AU Eisenhardt, P Simpson, C AF Eisenhardt, P Simpson, C BE Weymann, RJ StorrieLombardi, LJ Sawicki, M Brunner, RJ TI Photometric redshifts for distant galaxies using SIRTF's Infrared Array Camera SO PHOTOMETRIC REDSHIFTS AND HIGH REDSHIFT GALAXIES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Photometric Redshifts and High Redshift Galaxies CY APR 28-30, 1999 CL CARNEGIE OBSERV, PASADENA, CA HO CARNEGIE OBSERV ID TELESCOPE-FACILITY SIRTF; HUBBLE DEEP FIELD; STAR-FORMATION; LYMAN LIMIT; QSO FIELDS AB We discuss the ability of the Space Infrared Telescope Facility's Infrared Array Camera to detect distant (z similar to 3) galaxies and measure their photometric redshifts. We use an approach based on the 1.6 mu m peak in galaxy spectra, which is complementary to those based on the Lyman Break or the 4000 Angstrom break, because it scales linearly with dynamical mass locally, and is relatively insensitive to dust and to the current star formation rate. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Eisenhardt, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-327, Pasadena, CA 91109 USA. NR 17 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 1-58381-017-X J9 ASTR SOC P PY 1999 VL 191 BP 43 EP 48 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85J UT WOS:000086435000007 ER PT S AU Laskin, RA AF Laskin, RA BE Taylor, EW Berghmans, F TI The space interferometry mission (SIM) - Meeting the technology challenge SO PHOTONICS FOR SPACE AND RADIATION ENVIRONMENTS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Photonics for Space and Enhanced Radiation Environments CY SEP 20-21, 1999 CL UNIV FLORENCE, FLORENCE, ITALY SP Univ Florence, Dept Earth Sci, European Opt Soc, SPIE, CNR, NASA, Italian Soc Opt & Photon, Italian Space Agcy HO UNIV FLORENCE DE interferometry; metrology; pointing; control; nanometer; picometer; optics; lasers ID SPATIAL INTERFEROMETRY; METROLOGY 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, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 73 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 0-8194-3467-1 J9 P SOC PHOTO-OPT INS PY 1999 VL 3872 BP 95 EP 107 DI 10.1117/12.373274 PG 13 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BP46H UT WOS:000085207000011 ER PT J AU Marcinkevicius, S Leon, R AF Marcinkevicius, S Leon, R TI Carrier capture and emission in self-assembled InGaAs/GaAs quantum dots SO PHYSICA SCRIPTA LA English DT Article; Proceedings Paper CT 18th Nordic Semiconductor Meeting CY JUN 07-10, 1998 CL LINKOPING, SWEDEN SP Spectra Precision, Gamma Optronics, Epigress, Hamamatsu, Scandnordax, GammaData, Wafertech Sancdinavia, Crysis ID RELAXATION; LUMINESCENCE; LIFETIMES; STATES; WELLS AB We have investigated photoexcited carrier dynamics in as-grown and intermixed InGaAs/GaAs quantum dots and quantum wells by time-resolved photoluminescence with subpicosecond temporal resolution. Experiments were performed in the high excitation regime in the temperature range 60-300 K. At low temperatures, carrier lifetime in the dots is determined by the radiative recombination, while at temperatures over 150 K carrier thermal emission becomes dominant. Carrier capture into the dots was found to be fast and governed by the carrier-carrier scattering. In particular, the carrier capture time of 0.72 ps has been observed at room temperature and high excitation intensity for the intermixed dots. C1 Royal Inst Technol, Dept Phys Opt, S-10044 Stockholm, Sweden. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Marcinkevicius, S (reprint author), Royal Inst Technol, Dept Phys Opt, S-10044 Stockholm, Sweden. NR 16 TC 1 Z9 1 U1 0 U2 1 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1999 VL T79 BP 79 EP 82 DI 10.1238/Physica.Topical.079a00079 PG 4 WC Physics, Multidisciplinary SC Physics GA 188YW UT WOS:000079877800017 ER PT J AU Proffitt, CR Leckrone, DS AF Proffitt, CR Leckrone, DS TI The application of highly accurate laboratory wavelengths to abundance and isotope measurements in B stars SO PHYSICA SCRIPTA LA English DT Article; Proceedings Paper CT 6th International Colloquium on Atomic Spect and Oscillator Strengths (ASOS 6) CY AUG 09-13, 1998 CL UNIV VICTORIA, VICTORIA, CANADA SP Herzberg Inst Astrophys, Natl Res Council Canada, Natl Inst Stand & Technol, Univ Victoria, Dept Phys & Astron HO UNIV VICTORIA ID CHI-LUPI; ELEMENTS; BORON; GHRS AB The relative positions of absorption lines in stellar spectra observed at high dispersion and high signal-to-noise with the Hubble Space Telescope's Goddard High Resolution Spectrograph (HST/GHRS) can often be measured with a precision of about 0.001 Angstrom. Similar capabilities are expected from the Space Telescope Imaging Spectrograph (STIS). Under what circumstances do such astronomical data justify the acquisition of laboratory data with comparable accuracy? We will review a number of our GHRS spectra of B stars where such laboratory data have been critical to achieving our scientific goals. Studies of isotope ratios are one case where precision wavelengths are essential, and we will discuss our work on heavy element isotope anomalies in the HgMn stars chi Lupi and Hn 7775, as well as work on boron isotope ratios in early-B stars. In some cases the interpretation and even the identification of an individual absorption feature can be critically influenced by the laboratory data. C1 Comp Sci Corp, Sci Programs, Cincinnati, OH 45202 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. RP Proffitt, CR (reprint author), Comp Sci Corp, Sci Programs, Cincinnati, OH 45202 USA. NR 25 TC 0 Z9 0 U1 0 U2 1 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1999 VL T83 BP 128 EP 131 DI 10.1238/Physica.Topical.083a00128 PG 4 WC Physics, Multidisciplinary SC Physics GA 262UM UT WOS:000084084900017 ER PT J AU Greenwood, JB Smith, SJ Chutjian, A AF Greenwood, JB Smith, SJ Chutjian, A TI Absolute measurements of electron excitation cross sections in C3+ SO PHYSICA SCRIPTA LA English DT Article; Proceedings Paper CT IX International Conference on Physics of Highly Charged Ions CY SEP 09-14, 1998 CL BENSHEIM, GERMANY ID RESONANCE TRANSITIONS; IMPACT EXCITATION; 2S-2P EXCITATION AB Spectral emissions from C3+, of importance in solar, planetary and astrophysical plasmas. In these plasmas the population of excited states is often dominated by electron impact excitation. Accurate cross sections for this process are required to determine parameters such as electron and ion densities. The 2s S-2 - 2P 2P transition in C3+ is of particular interest as it allows direct comparisons among the results of several different experimental and theoretical groups. Employing the electron energy-loss technique we have measured cross sections to several eV above threshold, a region where there is still significant disagreement among previous results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chutjian, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Greenwood, Jason/L-4799-2014 NR 16 TC 1 Z9 1 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1999 VL T80B BP 281 EP 282 DI 10.1238/Physica.Topical.080a00281 PG 2 WC Physics, Multidisciplinary SC Physics GA 227RH UT WOS:000082093100045 ER PT J AU Bhatia, AK Drachman, RJ AF Bhatia, AK Drachman, RJ TI Polarizability of the ground state of the hydrogen molecular ion SO PHYSICAL REVIEW A LA English DT Article ID SPECTROSCOPY; H-2 AB The dipole polarizabilities of the ground states of the ions H-2(+) and D-2(+) have been calculated without making use of the Born-Oppenheimer approximation. Instead, the ions were treated as three-body systems whose ground states are spherically symmetric, and the polarizabilities were calculated using second-order perturbation theory with intermediate p pseudostates. The wave functions of both the ground and intermediate states are taken to be of generalized Hylleraas form, but it is necessary to use quite high powers of the internuclear coordinate to simulate the localized motion of the nuclei; We obtain good values of;the groundstate energies, and report values of the polarizabilities, to be compared with recent measurements. [S1050-2947(99)02001-6]. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 12 TC 40 Z9 40 U1 3 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JAN PY 1999 VL 59 IS 1 BP 205 EP 208 DI 10.1103/PhysRevA.59.205 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 158JD UT WOS:000078111500033 ER PT J AU Tuve, C Albergo, S Boemi, D Caccia, Z Chen, CX Costa, S Crawford, HJ Cronqvist, M Engelage, J Greiner, L Guzik, TG Knott, CN Insolia, A Lindstrom, PJ Mitchell, JW Potenza, R Russo, GV Soutoul, A Testard, O Tricomi, A Tull, CE Waddington, CJ Webber, WR Wefel, JP AF Tuve, C Albergo, S Boemi, D Caccia, Z Chen, CX Costa, S Crawford, HJ Cronqvist, M Engelage, J Greiner, L Guzik, TG Knott, CN Insolia, A Lindstrom, PJ Mitchell, JW Potenza, R Russo, GV Soutoul, A Testard, O Tricomi, A Tull, CE Waddington, CJ Webber, WR Wefel, JP TI Neutron production in coincidence with fragments from the Ca-40+H reaction at E-lab=357A and 565A MeV SO PHYSICAL REVIEW C LA English DT Article ID PRODUCTION CROSS-SECTIONS; HEAVY-ION COLLISIONS; AU-AU COLLISIONS; NICKEL PROJECTILES; RELATIVISTIC NEON; ENERGY-DEPENDENCE; HYDROGEN; INTERMEDIATE; CRITICALITY; 0-DEGREES AB Neutron production, in coincidence with fragments emitted in the Ca-40+H reaction at E-lab=357A and 565A MeV, has been measured using a 3-module version of the multifunctional neutron spectrometer MUFFINS. The mean neutron multiplicities for neutrons detected in the angular range covered by MUFFINS (0 degrees - 3.2 degrees) have been estimated from the comparison between the neutron cross sections, in coincidence with the fragments, and the elemental cross sections. We have found evidence for a preequilibrium emission of prompt neutrons in superposition to a "slower" deexcitation of the equilibrated remnant by emission of nucleons and fragments, as already seen in inclusive rapidity distributions. The energy dependence of die inclusive neutron production cross sections, measured in a previous work, is here interpreted as due to the stronger neutron focusing in the forward direction at the higher energy. Comparison with a BNV+phase space coalescence model is discussed. [S0556-2813(99)01101-2]. C1 Univ Catania, I-95129 Catania, Italy. Ist Nazl Fis Nucl, I-95129 Catania, Italy. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Minnesota, Minneapolis, MN 55455 USA. New Mexico State Univ, Las Cruces, NM 88003 USA. CENS, Serv Astrophys, F-91191 Gif Sur Yvette, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Catania, I-95129 Catania, Italy. RI Insolia, Antonio/M-3447-2015; TUVE', Cristina/P-3933-2015; OI Insolia, Antonio/0000-0002-9040-1566; TUVE', Cristina/0000-0003-0739-3153; Tricomi, Alessia Rita/0000-0002-5071-5501; Costa, Salvatore/0000-0001-9919-0569 NR 25 TC 5 Z9 5 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD JAN PY 1999 VL 59 IS 1 BP 233 EP 238 PG 6 WC Physics, Nuclear SC Physics GA 158JC UT WOS:000078111400027 ER PT B AU Kleinsasser, AW AF Kleinsasser, AW BE Ohta, H Ishii, C TI High-T-c SNS junctions: A new generation of proximity-coupled Josephson devices SO PHYSICS AND APPLICATIONS OF MESOSCOPIC JOSEPHSON JUNCTIONS LA English DT Proceedings Paper CT International Symposium on Physics and Applications of Mesoscopic Josephson Junctions CY MAR 06-07, 1997 CL COMMUN RES LAB, JAPAN SP Ctr Excellence HO COMMUN RES LAB ID SUPERCONDUCTOR-SEMICONDUCTOR CONTACTS; EDGE JUNCTIONS; STATIONARY PROPERTIES; CRITICAL-TEMPERATURE; WEAK LINKS; DC SQUIDS; BARRIER; SILICON; CONSTRICTIONS; YBA2CU3O7-X AB The subjects of mesoscopic Josephson junctions and the proximity effect are intimately related. This paper reviews this evolution of proximity-coupled Josephson junctions from the early investigations on low temperature superconductor-normal-superconductor junctions through the introduction of hybrid superconductor-semiconductor devices and the resulting interest in mesoscopic Josephson junctions, to the recent development of high temperature devices. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kleinsasser, AW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 56 TC 0 Z9 0 U1 0 U2 1 PU PHYSICAL SOCIETY JAPAN PI TOKYO PA RM 211 KIKAI-SHINKO BLDG 3-5-8 SHIBA KOEN MINATO-KU, TOKYO, 105, JAPAN BN 4-89027-007-8 PY 1999 BP 179 EP 195 PG 17 WC Thermodynamics; Physics, Condensed Matter; Physics, Mathematical SC Thermodynamics; Physics GA BP31B UT WOS:000084658800010 ER PT J AU Pauluhn, A Chao, Y AF Pauluhn, A Chao, Y TI Tracking eddies in the subtropical north-western Atlantic Ocean SO PHYSICS AND CHEMISTRY OF THE EARTH PART A-SOLID EARTH AND GEODESY LA English DT Article ID BRAZIL CURRENT RETROFLECTION AB Anticyclonic eddies generated in the North Brazil Current retroflection area are traced along the coast of North Brazil and into the Caribbean Sea using TOPEX/ POSEIDON altimetric observations and a 1/6 degrees eddy-resolving ocean general circulation model simulation. About 16 to 20 anticyclonic eddies were identified during the period from October 1992 to June 1997. These eddies propagate northwestward along the continental shelf. As these eddies approach the Lesser Antilles island chain, their amplitudes decrease. Most of these eddies were able to penetrate the narrow passages of the Windward Islands. Once they enter the Caribbean Sea, their amplitudes increase, probably due to the strong meridional shear of the Caribbean Current. It takes more than a year for these eddies to travel from the North Brazil coast, through the Caribbean Sea and eventually to the Yucatan Peninsula. The observed eddy sizes range from 200 to 600 km, their average amplitude is about 15 cm, their average propagation speed is around 14 cm/s, and their time scale is about 80 to 100 days. In contrast to the tropical instability waves which are only present in the autumn season, no seasonal dependence is observed in the generation of these anticyclonic eddies. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Hamburg, Inst Meereskunde, D-2000 Hamburg, Germany. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Pauluhn, A (reprint author), HTA Bern, INTEC, Bern, Switzerland. NR 18 TC 10 Z9 10 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1895 J9 PHYS CHEM EARTH PT A JI Phys. Chem. Earth Pt. A-Solid Earth Geod. PY 1999 VL 24 IS 4 BP 415 EP 421 DI 10.1016/S1464-1895(99)00052-6 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 234RD UT WOS:000082497400017 ER PT J AU Davis, AB Cahalan, RF Spinehirne, D McGill, MJ Love, SP AF Davis, AB Cahalan, RF Spinehirne, D McGill, MJ Love, SP TI Off-beam lidar: an emerging technique in cloud remote sensing based on radiative Green-function theory in the diffusion domain SO PHYSICS AND CHEMISTRY OF THE EARTH PART B-HYDROLOGY OCEANS AND ATMOSPHERE LA English DT Article ID STRATOCUMULUS; SPACE AB Atmospheric lidars do not penetrate directly most boundary-layer clouds due to their large optical density. However, the lidar's photons are not absorbed but scattered out of the beam. Typically, about half are actually transmitted through the cloud and the other half escape the cloud by reflection in extended diffuse patterns that evolve in time. For all practical purposes, these are the cloud's space-time Green functions (GFs). In a Fourier-Laplace expansion of the space-time GF, the leading term is representative of solar remote-sensing (i.e., steady/uniform source) while higher-order terms correspond to active approaches with temporal- and/or spatial- resolution capabilities. Radiative GF theory is tractable within the limits of photon-diffusion theory and homogeneous clouds. Monte Carlo simulations with realistically variable cloud models are used to extend the range of validity of analytical GF theory with minor modifications. GF theory tells us that physical and optical cloud thicknesses can be retrieved from off-beam cloud lidar returns. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, Space & Remote Sensing Sci Grp NIS 2, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Mesoscale Dynam Branch, Greenbelt, MD 20771 USA. RP Davis, AB (reprint author), Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, Space & Remote Sensing Sci Grp NIS 2, POB 1663,Mail Stop C-323, Los Alamos, NM 87545 USA. RI McGill, Matthew/D-8176-2012; Cahalan, Robert/E-3462-2012 OI Cahalan, Robert/0000-0001-9724-1270 NR 25 TC 22 Z9 23 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1909 J9 PHYS CHEM EARTH PT B JI Phys. Chem. Earth Pt B-Hydrol. Oceans Atmos. PY 1999 VL 24 IS 3 BP 177 EP 185 DI 10.1016/S1464-1909(98)00034-3 PG 9 WC Meteorology & Atmospheric Sciences; Oceanography; Water Resources SC Meteorology & Atmospheric Sciences; Oceanography; Water Resources GA 234NT UT WOS:000082491300005 ER PT J AU Chepfer, H Goloub, P Sauvage, L Flamant, PH Brogniez, G Spinhirne, J Lavorato, M Sugimoto, N Pelon, J AF Chepfer, H Goloub, P Sauvage, L Flamant, PH Brogniez, G Spinhirne, J Lavorato, M Sugimoto, N Pelon, J TI Validation of POLDER/ADEOS data using a ground-based lidar network: Preliminary results for cirrus clouds SO PHYSICS AND CHEMISTRY OF THE EARTH PART B-HYDROLOGY OCEANS AND ATMOSPHERE LA English DT Article ID POLARIZATION AB POLDER-1 on board the Japanese ADEOS platform has collected 8 months of data (October 1996 to June 1997). POLDER is a visible radiometer with multi-directional and polarization capabilities. These features allow to obtain information both on cloud thermodynamical phase and cloud altitude. The POLDER cloud algorithms are currently under validation. For cirrus clouds, a validation based on a comparison between cloud properties inferred from POLDER-1 data and cloud properties retrieved from a ground-based lidar network is currently under consideration. In this paper, preliminary comparisons between cloud altitude inferred from POLDER-1 and lidars are presented. These comparisons show an underestimation of cloud altitude by POLDER-1 for optically thin clouds. A first theoretical analysis based on radiative transfer simulations allows to explain the difference between POLDER and lidar altitudes. Moreover. a preliminary comparison between thermodynamical cloud phase (liquid water / ice) obtained with POLDER-1 and cloud temperature inferred from radiosoundings and cloud altitudes shows that cirrus clouds at temperatures lower than -40 degrees C are correctly identified as ice layers by POLDER-1 (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Ecole Polytech, Inst Pierre Simon Laplace, Meteorol Dynam Lab, F-91128 Palaiseau, France. Univ Lille 1, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CONICET, CEILAP, CITELA, Villa Martelli, Argentina. Natl Inst Environm Studies, Tsukuba, Ibaraki, Japan. RP Chepfer, H (reprint author), Ecole Polytech, Inst Pierre Simon Laplace, Meteorol Dynam Lab, F-91128 Palaiseau, France. RI Sugimoto, Nobuo/C-5189-2015 OI Sugimoto, Nobuo/0000-0002-0545-1316 NR 7 TC 5 Z9 6 U1 2 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1909 J9 PHYS CHEM EARTH PT B JI Phys. Chem. Earth Pt B-Hydrol. Oceans Atmos. PY 1999 VL 24 IS 3 BP 203 EP 206 DI 10.1016/S1464-1909(98)00038-0 PG 4 WC Meteorology & Atmospheric Sciences; Oceanography; Water Resources SC Meteorology & Atmospheric Sciences; Oceanography; Water Resources GA 234NT UT WOS:000082491300009 ER PT J AU Davies, AB Cahalan, RF Spinhirne, JD McGill, MJ Love, SP AF Davies, AB Cahalan, RF Spinhirne, JD McGill, MJ Love, SP TI Off-beam lidar: An emerging technique in cloud remote sensing based on radiative green-function theory in the diffusion domain (vol 24, pg 177, 1999) SO PHYSICS AND CHEMISTRY OF THE EARTH PART B-HYDROLOGY OCEANS AND ATMOSPHERE LA English DT Correction ID STRATOCUMULUS; SPACE AB Atmospheric lidars do not penetrate directly most boundary-layer clouds due to their large optical density. However, the lidar's photons are not absorbed but scattered out of the beam. Typically, about half are actually transmitted through the cloud and the other half escape the cloud by reflection in extended diffuse patterns that evolve in time. For all practical purposes, these are the cloud's space-time Green functions (GFs). In a Fourier-Laplace expansion of the space-time GF, the leading term is representative of solar remote-sensing (i.e., steady/uniform source) while higher-order terms correspond to active approaches with temporal- and/or spatial- resolution capabilities. Radiative GF theory is tractable within the limits of photon-diffusion theory and homogeneous clouds. Monte Carlo simulations with realistically variable cloud models are used to extend the range of validity of analytical GF theory with minor modifications. GF theory tells us that physical and optical cloud thicknesses can be retrieved from off-beam cloud lidar returns. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Space & Remote Sensing Sci Grp NIS2, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Mesoscale Dynam Branch, Greenbelt, MD 20771 USA. RP Davies, AB (reprint author), Univ Calif Los Alamos Natl Lab, Space & Remote Sensing Sci Grp NIS2, POB 1663,Mail Stop C-323, Los Alamos, NM 87545 USA. RI McGill, Matthew/D-8176-2012 NR 26 TC 24 Z9 24 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1909 J9 PHYS CHEM EARTH PT B JI Phys. Chem. Earth Pt B-Hydrol. Oceans Atmos. PY 1999 VL 24 IS 6 BP 757 EP 765 DI 10.1016/S1464-1909(99)00077-5 PG 9 WC Meteorology & Atmospheric Sciences; Oceanography; Water Resources SC Meteorology & Atmospheric Sciences; Oceanography; Water Resources GA 235EA UT WOS:000082526000043 ER PT J AU Ducharne, A Koster, RD Suarez, MJ Kumar, P AF Ducharne, A Koster, RD Suarez, MJ Kumar, P TI A catchment-based land surface model for GCMs and the framework for its evaluation SO PHYSICS AND CHEMISTRY OF THE EARTH PART B-HYDROLOGY OCEANS AND ATMOSPHERE LA English DT Article ID SOIL-MOISTURE; HYDROLOGY; SCHEMES; RUNOFF; PARAMETRIZATION; SENSITIVITY; SIMILARITY; TOPMODEL; BOUNDARY; PROJECT AB A new GCM-scale land surface modeling strategy that explicitly accounts for subgrid soil moisture variability and its effects on evaporation and runoff is now being explored. In a break from traditional modeling strategies, the continental surface is disaggregated into a mosaic of hydrological catchments, with boundaries that are not dictated by a regular grid but by topography. Within each catchment, the variability of soil moisture is deduced from TOP-MODEL equations with a special treatment of the unsaturated zone. This paper gives an overview of this new approach and presents the general framework for its off-line evaluation over North-America. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Lab Atmospheres Climate & Radiat Branch, Greenbelt, MD 20771 USA. Univ Illinois, Dept Civil Engn, Urbana, IL 61801 USA. RP Ducharne, A (reprint author), Univ Space Res Assoc, Greenbelt, MD 20771 USA. RI Kumar, Praveen/D-2036-2010; Koster, Randal/F-5881-2012 OI Kumar, Praveen/0000-0002-4787-0308; Koster, Randal/0000-0001-6418-6383 NR 27 TC 7 Z9 7 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1909 J9 PHYS CHEM EARTH PT B JI Phys. Chem. Earth Pt B-Hydrol. Oceans Atmos. PY 1999 VL 24 IS 7 BP 769 EP 773 DI 10.1016/S1464-1909(99)00078-7 PG 5 WC Meteorology & Atmospheric Sciences; Oceanography; Water Resources SC Meteorology & Atmospheric Sciences; Oceanography; Water Resources GA 235EB UT WOS:000082526100002 ER PT J AU Daglis, IA Baumjohann, W Gleiss, J Orsini, S Sarris, ET Scholer, M Tsurutani, BT Vassiliadis, D AF Daglis, IA Baumjohann, W Gleiss, J Orsini, S Sarris, ET Scholer, M Tsurutani, BT Vassiliadis, D TI Recent advances, open questions and future directions in solar-terrestrial research SO PHYSICS AND CHEMISTRY OF THE EARTH PART C-SOLAR-TERRESTIAL AND PLANETARY SCIENCE LA English DT Article ID ENERGETIC NEUTRAL ATOMS; LATITUDE BOUNDARY-LAYER; MAGNETOSPHERIC ION COMPOSITION; INTERPLANETARY MAGNETIC-FIELD; PLASMA SHEET INSTABILITIES; FLUX-TRANSFER EVENTS; CROSS-TAIL CURRENT; RING CURRENT; AMPTE CCE; GEOMAGNETIC STORMS AB The International Symposium on Solar-Terrestrial Coupling Processes was held in Paros, Greece, on June 23-27, 1997. The Symposium was sponsored by NASA, the European Geophysical Society, the Creek Ministry of the Aegean, and the Creek Ministry of Development. It was attended by 85 scientists from 13 countries, and included six sessions on topics ranging from Interplanetary Disturbances to Particle Acceleration. In addition to the six sessions a panel discussion session was held. Eight scientists reported on recent advances, open questions and future directions in solar-terrestrial research. This review paper is based on the panelists' reports and includes individual sections on seven particular topics of special interest to solar-terrestrial research. The topics range from the significance of solar wind composition and interplanetary disturbances to promising new technologies and methods. Solar-terrestrial research deserves the special attention of the scientific community, both because of the attractive physics underlying the various phenomena associated with them, as well as because of the applied aspect of the sometimes destructive effects of solar-terrestrial coupling on a wide variety of technological systems. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Natl Observ Athens, Inst Ionospher & Space Res, Penteli 15236, Greece. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Int Space Sci Inst, CH-3012 Bern, Switzerland. CNR, Ist Fis Spazio Interplanetario, I-00133 Rome, Italy. Democritus Univ Thrace, GR-67100 Xanthi, Greece. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Daglis, IA (reprint author), Natl Observ Athens, Inst Ionospher & Space Res, Penteli 15236, Greece. RI Baumjohann, Wolfgang/A-1012-2010; Daglis, Ioannis/L-6100-2013 OI Baumjohann, Wolfgang/0000-0001-6271-0110; Daglis, Ioannis/0000-0002-0764-3442 NR 160 TC 15 Z9 15 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1917 J9 PHYS CHEM EARTH PT C JI Phys. Chem. Earth Pt. C-Solar-Terr. Planet. Sci. PY 1999 VL 24 IS 1-3 BP 5 EP 28 DI 10.1016/S1464-1917(98)00003-8 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 238LM UT WOS:000082711800003 ER PT J AU Klimas, AJ Vassiliadis, D Baker, DN Valdivia, JA AF Klimas, AJ Vassiliadis, D Baker, DN Valdivia, JA TI Data-derived analogues of the solar wind-magnetosphere interaction SO PHYSICS AND CHEMISTRY OF THE EARTH PART C-SOLAR-TERRESTIAL AND PLANETARY SCIENCE LA English DT Article ID GEOMAGNETIC-ACTIVITY; PREDICTION; DYNAMICS; MODELS AB Nonlinear dynamics methods have been applied successfully to predict various aspects of geomagnetic activity. In the local-linear prediction method past input and output data are convolved with filter functions to produce a prediction of future output. For solar wind input and geomagnetic activity output, the local-linear filter functions constitute a low-dimensional nonlinear model of the magnetospheric dynamics. This prediction model is data-derived; it is an unbiased representation of the magnetospheric dynamics. In principle this model contains a wealth of data-derived information concerning substorm and storm processes. Such models, however, are not amenable to physical interpretation. We present a method for transforming a local-linear prediction model to dynamical system analogues of two types: (1) A local-linear analogue composed of readily recognized physical components, suitable for identifying time-scales, coupling strengths, dissipation rates, etc. implied by the input-output data. (2) For prediction applications, a nonlinear analogue containing a small number of free parameters which are fixed from a training interval in the input-output data. Both of these are data-derived, low order, ordinary differential equations. They represent the collective effects of the many magnetospheric phenomena that couple the solar wind driver to the geomagnetic response. We illustrate the method using intervals of ISEE-3 and IMP-8 solar wind data for input, and D-st and AL index data for output. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Space Res Assoc, Seabrook, MD 20706 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Natl Res Council, Greenbelt, MD 20771 USA. RP Klimas, AJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Valdivia, Juan/A-3631-2008 OI Valdivia, Juan/0000-0003-3381-9904 NR 18 TC 9 Z9 9 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1917 J9 PHYS CHEM EARTH PT C JI Phys. Chem. Earth Pt. C-Solar-Terr. Planet. Sci. PY 1999 VL 24 IS 1-3 BP 37 EP 44 DI 10.1016/S1464-1917(98)00005-1 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 238LM UT WOS:000082711800005 ER PT J AU Tsurutani, BT Gonzalez, WD Kamide, Y Ho, CM Lakhina, GS Arballo, JK Thorne, RM Pickett, JS Howard, RA AF Tsurutani, BT Gonzalez, WD Kamide, Y Ho, CM Lakhina, GS Arballo, JK Thorne, RM Pickett, JS Howard, RA TI The interplanetary causes of magnetic storms, HILDCAAs and viscous interaction SO PHYSICS AND CHEMISTRY OF THE EARTH PART C-SOLAR-TERRESTIAL AND PLANETARY SCIENCE LA English DT Article ID SOLAR-WIND; ULYSSES OBSERVATIONS; GEOMAGNETIC-ACTIVITY; INTERACTION REGIONS; ALFVEN WAVES; HEAVY-IONS; MAGNETOSPHERE; PLASMA; ORIGIN; IRON AB A review of the interplanetary causes of geomagnetic activity is presented. Intense southward interplanetary magnetic fields in the sheath region ahead of fast interplanetary manifestations of solar CMEs (ICMEs), acid the intrinsically high B-Z fields of magnetic clouds within ICMEs, are the two most predominant causes of major storms with D-ST less than or equal to -100 nT. This is true during solar maximum when ICMEs dominate the interplanetary medium and also during the declining phase of the solar cycle when corotating streams and proto-corotating interaction regions (PCIRs) are the dominant large scale structures. PCIRs are high magnetic field regions caused by the interaction of coronal hole high-speed streams with the upstream slow speed streams. PCIRs cause only moderate to weak magnetic storms (rarely storms with D-ST less than or equal to -100 nT) because of the highly variable B-Z structure within them. It is thought that the B-Z fluctuations within the PCIR are compressed high-speed stream Alfven waves. The B-Z fluctuations associated with nonlinear Alfven waves within the high-speed streams cause continuous auroral activity called HILDCAAs. These HILDCAA events lead to annual AE averages that are sometimes higher during the solar cycle descending phase (such as in 1974) than during solar maximum (1979 or 1981). We quantify an upper limit of the efficiency of viscous interaction energy input into the magnetosphere: 1 to 3 x 10(-3) of the solar wind ram energy. This is in contrast to an efficiency of 5 to 10 x 10(-2) for magnetic reconnection during substorms and magnetic storms. Finally, a specific mechanism of viscous interaction is explored: low latitude boundary layer (LLBL) resonant wave-particle interactions. The waves are sufficiently intense to cross-field diffuse magnetosheath plasma onto closed field lines to create the LLBL. Pitch angle scattering will lead to auroral energy deposition of similar to 1 erg cm(-2) s(-1), sufficient for the creation of the dayside aurora. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Inst Nacl Pesquisas Espaciais, BR-12201 Sao Jose Dos Campos, SP, Brazil. Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Aichi 442, Japan. Indian Inst Geomagnetism, Bombay 400005, Maharashtra, India. Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90024 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Lakhina, Gurbax /C-9295-2012; OI Lakhina, Gurbax /0000-0002-8956-486X NR 41 TC 9 Z9 9 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1917 J9 PHYS CHEM EARTH PT C JI Phys. Chem. Earth Pt. C-Solar-Terr. Planet. Sci. PY 1999 VL 24 IS 1-3 BP 93 EP 99 DI 10.1016/S1464-1917(98)00014-2 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 238LM UT WOS:000082711800014 ER EF