FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Hjorvarsson, B Dura, JA Isberg, P Watanabe, T Udovic, TJ Andersson, G Majkrzak, CF AF Hjorvarsson, B Dura, JA Isberg, P Watanabe, T Udovic, TJ Andersson, G Majkrzak, CF TI Reversible tuning of the magnetic exchange coupling in Fe/V (001) superlattices using hydrogen SO PHYSICAL REVIEW LETTERS LA English DT Article ID LAYERS AB The interlayer ordering between ferromagnetic Fe layers in Fe/V (001)superlattices is switched from initially parallel to antiparallel, as well as antiparallel to parallel, upon introducing hydrogen to the V layers. This process is reversible upon removal of the hydrogen. the results unambiguously prove that the major cause of the interlayer coupling transitions is not the hydrogen-induced changes of the thickness of the V layers, but most likely the distortion of the Fermi surface in the V layers. C1 NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. RP Hjorvarsson, B (reprint author), UNIV UPPSALA, DEPT PHYS, BOX 530, S-75121 UPPSALA, SWEDEN. RI Dura, Joseph/B-8452-2008; Hjorvarsson, Bjorgvin/B-3022-2011; OI Dura, Joseph/0000-0001-6877-959X; Hjorvarsson, Bjorgvin/0000-0003-1803-9467; Andersson, Gabriella/0000-0002-9479-1952 NR 16 TC 116 Z9 116 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD AUG 4 PY 1997 VL 79 IS 5 BP 901 EP 904 DI 10.1103/PhysRevLett.79.901 PG 4 WC Physics, Multidisciplinary SC Physics GA XN809 UT WOS:A1997XN80900032 ER PT J AU Dunn, ML Ledbetter, H AF Dunn, ML Ledbetter, H TI Elastic-plastic behavior of textured short-fiber composites SO ACTA MATERIALIA LA English DT Article ID METAL-MATRIX COMPOSITES; FINITE-ELEMENT TECHNIQUES; AL-SIC COMPOSITES; ELASTOPLASTIC BEHAVIOR; REINFORCED COMPOSITES; RESIDUAL-STRESS; MULTIPHASE MATERIALS; TENSILE PROPERTIES; DEFORMATION; CONSTANTS AB We propose a relatively simple micromechanics model to predict the elastic-plastic response of short-fiber composites with a preferred orientation of the reinforcement, i.e. a texture. Our theoretical efforts are directed toward a composite system with an elastic-plastic matrix containing elastic reinforcement, but the extension to allow elastic-plastic response of the reinforcement is straightforward. The theory is based on the combination of our recent model for textured elasticity of short-fiber composites and the often-used idea of a linear comparison composite to simulate the nonlinear behavior of the actual composite as proposed by Hill(J. Mech. Phys. Solids, 1965, 13, 89) and Hutchinson (Proc. R. Sec. London, 1970, A319, 247). We compute the effective stress of the heterogeneously deforming matrix from the distortional energy of the matrix using the approach recently proposed by Qiu and Weng (J. appl. Mech., 1992, 59, 261, J. appl. Mech., 1995, 62, 1039). We give simple, easily used, results for orientation distributions of practical significance. We compare our predictions with measured stress-strain curves for an extruded SiC/6061-Al short-fiber composite with a fiber orientation distribution that is axially symmetric about the extrusion axis. The predictions are in excellent agreement with measurements for the axial and transverse Young's moduli and the 0.2% yield stress. Good agreement is obtained between the predicted and measured how stress over the entire range of deformation. (C) 1997 Acta Metallurgica Inc. C1 NATL INST STAND & TECHNOL,MAT SCI & ENGN LAB,BOULDER,CO 80303. RP Dunn, ML (reprint author), UNIV COLORADO,DEPT MECH ENGN,CTR ACOUST MECH & MAT,BOULDER,CO 80309, USA. OI DUNN, MARTIN/0000-0002-4531-9176 NR 70 TC 41 Z9 41 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD AUG PY 1997 VL 45 IS 8 BP 3327 EP 3340 DI 10.1016/S1359-6454(96)00401-6 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA XP072 UT WOS:A1997XP07200022 ER PT J AU Brandt, JC Heap, SR Beaver, EA Boggess, A Carpenter, KG Ebbets, DC Hutchings, JB Jura, M Leckrone, DS Linsky, JL Maran, SP Savage, BD Smith, AM Trafton, LM Walter, FM Weymann, RJ Snow, M Randall, CE Tripp, TM Ake, TB Crenshaw, DM Bruhweiler, FC AF Brandt, JC Heap, SR Beaver, EA Boggess, A Carpenter, KG Ebbets, DC Hutchings, JB Jura, M Leckrone, DS Linsky, JL Maran, SP Savage, BD Smith, AM Trafton, LM Walter, FM Weymann, RJ Snow, M Randall, CE Tripp, TM Ake, TB Crenshaw, DM Bruhweiler, FC TI Observations of 3C 273 with the Goddard High Resolution Spectrograph on the Hubble Space Telescope .2. SO ASTRONOMICAL JOURNAL LA English DT Article ID LYMAN-ALPHA CLOUDS; GALACTIC HALO; LOW-REDSHIFT; 3C-273; ABSORPTION; ABUNDANCE; SYSTEMS; SIGHT AB Observations of the quasar 3C 273 taken with the Goddard High Resolution Spectrograph in 1993 November and December are presented here. We have included both the fully-reduced spectra, and spectra combined with our earlier (1991) observations. There are a total of IO new medium resolution exposures covering four wavelength regions: 1164-1201 Angstrom, 1214-1251 Angstrom, 1537-1573 Angstrom, and 1633-1670 Angstrom. We confirm the suggestion of Morris et al. (1991, ApJ, 377, L21) that the galactic Si IV lambda 1393 line is blended with an extragalactic Ly alpha line by observing the Ly beta counterpart to this extragalactic line. We obtain an improved upper limit on the C IV/H I ratio in these weak low redshift Ly alpha absorption systems by coadding the corresponding C IV spectral regions. Improved line profiles for the galactic C IV and N V absorption are also presented and discussed. The improved measurements lead to a downward revision of the galactic C IV column density, log N(C IV) = 14.46+/-0.04. (C) 1997 American Astronomical Society. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV CALIF SAN DIEGO,CTR ASTROPHYS & SPACE SCI,LA JOLLA,CA 92093. BALL AEROSP & TECHNOL CORP,BOULDER,CO 80306. DOMINION ASTROPHYS OBSERV,VICTORIA,BC V8X 4M6,CANADA. UNIV CALIF LOS ANGELES,DEPT PHYS & ASTRON,LOS ANGELES,CA 90095. UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. NASA,GODDARD SPACE FLIGHT CTR,SPACE SCI DIRECTORATE,GREENBELT,MD 20771. UNIV WISCONSIN,DEPT AGRON,MADISON,WI 53706. UNIV TEXAS,MCDONALD OBSERV,AUSTIN,TX 78712. UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. SUNY STONY BROOK,STONY BROOK,NY 11794. OBSERV CARNEGIE INST WASHINGTON,PASADENA,CA 91101. UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,BOULDER,CO 80309. PRINCETON UNIV OBSERV,PRINCETON,NJ 08544. NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,SCI PROGRAMS,GREENBELT,MD 20771. CATHOLIC UNIV AMER,INST ASTROPHYS,WASHINGTON,DC 20064. RP Brandt, JC (reprint author), UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,CAMPUS BOX 392,BOULDER,CO 80309, USA. RI heap, sara/E-2237-2012; Carpenter, Kenneth/D-4740-2012; Randall, Cora/L-8760-2014 OI Randall, Cora/0000-0002-4313-4397 NR 18 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 1997 VL 114 IS 2 BP 554 EP 564 DI 10.1086/118492 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XN548 UT WOS:A1997XN54800007 ER PT J AU Meyers, MP Walko, RL Harrington, JY Cotton, WR AF Meyers, MP Walko, RL Harrington, JY Cotton, WR TI New RAMS cloud microphysics parameterization .2. The two-moment scheme SO ATMOSPHERIC RESEARCH LA English DT Article ID SECONDARY ICE PARTICLES; NUMERICAL-SIMULATION; MICROSCALE STRUCTURE; SIZE DISTRIBUTIONS; CONVECTIVE CLOUDS; FRONTAL RAINBANDS; MODEL DESCRIPTION; WIND-TUNNEL; GRAUPEL; COLLECTION AB This paper is the second in a series of articles describing the new microphysics scheme in the Regional Atmospheric Modeling System (RAMS). in this part, a new two-moment microphysical parameterization is described. The proposed scheme predicts the mixing ratio and number concentration of rain, pristine ice crystals, snow, aggregates, graupel and hail. The general gamma distribution is the basis function used for hydrometeor size in each category. Additional features include: use of stochastic collection for number concentration tendency; breakup of rain droplets formulated into the collection efficiency; diagnosis of ice crystal habit dependent on temperature and saturation; evaporation and melting of each species assuming that the smallest particles completely disappear first; and more complex shedding formulations which take into account the amount of water mass on the coalesced hydrometeor. Preliminary sensitivity testing of the new microphysical scheme in an idealized convective simulation shows that the two-moment prediction scheme allows more flexibility of the size distribution enabling the mean diameter to evolve in contrast to the one-moment scheme. Sensitivity to the prescribed input parameters such as cloud droplet concentrations and the shape parameter nu is demonstrated in the model results. (C) 1997 Elsevier Science B.V. C1 COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523. RP Meyers, MP (reprint author), NATL WEATHER SERV,792 EAGLE DR,GRAND JCT,CO 81506, USA. NR 45 TC 274 Z9 298 U1 2 U2 13 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD AUG PY 1997 VL 45 IS 1 BP 3 EP 39 DI 10.1016/S0169-8095(97)00018-5 PG 37 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YK819 UT WOS:A1997YK81900002 ER PT J AU Griffies, SM Bryan, K AF Griffies, SM Bryan, K TI A predictability study of simulated North Atlantic multidecadal variability SO CLIMATE DYNAMICS LA English DT Article ID DECADAL CLIMATE VARIABILITY; OCEAN-ATMOSPHERE MODELS; THERMOHALINE CIRCULATION; TRANSIENT RESPONSES; GRADUAL CHANGES; HEAT-TRANSPORT; DYNAMICS; CO2; OSCILLATION; RESOLUTION AB The North Atlantic is one of the few places on the globe where the atmosphere is linked to the deep ocean through air-sea interaction. While the internal variability of the atmosphere by itself is only predictable over a period of one to two weeks, climate Variations are potentially predictable for much longer periods of months or even years because of coupling with the ocean. This work presents details from the first study to quantify the predictability for simulated multidecadal climate variability over the North Atlantic. The model used for this purpose is the GFDL coupled ocean-atmosphere climate model used extensively for studies of global warming and natural climate variability. This model contains fluctuations of the North Atlantic and high-latitude oceanic circulation with variability concentrated in the 40-60 year range. Oceanic predictability is quantified through analysis of the time-dependent behavior of large-scale empirical orthogonal function (EOF) patterns for the meridional stream function, dynamic topography, 170 m temperature, surface temperature and surface salinity. The results indicate that predictability in the North Atlantic depends on three main physical mechanisms. The first involves the oceanic deep convection in the subpolar region which acts to integrate atmospheric fluctuations, thus providing for a red noise oceanic response as elaborated by Hasselmann. The second involves the large-scale dynamics of the thermohaline circulation, which can cause the oceanic variations to have an oscillatory character on the multidecadal time scale. The third involves nonlocal effects on the North Atlantic arising from periodic anomalous fresh water transport advecting southward from the polar regions in the East Greenland Current. When the multidecadal oscillatory variations of the thermohaline circulation are active, the first and second EOF patterns for the North Atlantic dynamic topography have predictability time scales on the order of 10-20 y, whereas EOF-1 of SST has predictability time scales of 5-7 y. When the thermohaline variability has weak multidecadal power, the Hasselmann mechanism is dominant and the predictability is reduced by at least a factor of two. When the third mechanism is in an extreme phase, the North Atlantic dynamic topography patterns realize a 10-20 year predictability time scale. Additional analysis of SST in the Greenland Sea, in a region associated with the southward propagating fresh water anomalies, indicates the potential for decadal scale predictability for this high latitude region as well. The model calculations also allow insight into regional variations of predictability, which might be useful information for the design of a monitoring system for the North Atlantic. Predictability appears to break down most rapidly in regions of active convection in the high-latitude regions of the North Atlantic. C1 PRINCETON UNIV,ATMOSPHER & OCEAN SCI PROGRAM,PRINCETON,NJ 08544. RP Griffies, SM (reprint author), GEOPHYS FLUID DYNAM LAB,ROUTE 1,FORRESTAL CAMPUS,PRINCETON,NJ 08542, USA. NR 54 TC 108 Z9 109 U1 1 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD AUG PY 1997 VL 13 IS 7-8 BP 459 EP 487 DI 10.1007/s003820050177 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XX047 UT WOS:A1997XX04700001 ER PT J AU Berger, JR Tewary, VK AF Berger, JR Tewary, VK TI Boundary integral equation formulation for interface cracks in anisotropic materials SO COMPUTATIONAL MECHANICS LA English DT Article ID STRESS INTENSITY FACTORS; ELASTIC GREEN-FUNCTION; BICRYSTAL INTERFACES; ELEMENT ANALYSIS; BIMATERIAL; MEDIA AB We present a boundary integral formulation for anisotropic interface crack problems based on an exact Green's function. The fundamental displacement and traction solutions needed for the boundary integral equations are obtained from the Green's function. The traction-free boundary conditions on the crack faces are satisfied exactly with the Green's function so no discretization of the crack surfaces is necessary. The analytic forms of the interface crack displacement and stress fields are contained in the exact Green's function thereby offering advantage over modeling strategies for the crack. The Green's function contains both the inverse square root and oscillatory singularities associated with the elastic, anisotropic interface crack problem. The integral equations for a boundary element analysis are presented and an example problem given for interface cracking in a copper-nickel bimaterial. C1 NATL INST STAND & TECHNOL,DIV MAT RELIABIL,BOULDER,CO 80303. RP Berger, JR (reprint author), COLORADO SCH MINES,DIV ENGN,GOLDEN,CO 80401, USA. RI Berger, John/F-5169-2010 NR 18 TC 16 Z9 16 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0178-7675 J9 COMPUT MECH JI Comput. Mech. PD AUG PY 1997 VL 20 IS 3 BP 261 EP 266 DI 10.1007/s004660050246 PG 6 WC Mathematics, Interdisciplinary Applications; Mechanics SC Mathematics; Mechanics GA XW394 UT WOS:A1997XW39400007 ER PT J AU Jayaram, S Connacher, HI Lyons, KW AF Jayaram, S Connacher, HI Lyons, KW TI Virtual assembly using virtual reality techniques SO COMPUTER-AIDED DESIGN LA English DT Article DE virtual reality; virtual prototyping; virtual assembly; path planning; design by manufacture; virtual manufacturing AB Virtual reality is a technology which is often regarded as a natural extension to 3D computer graphics with advanced input and output devices. This technology has only recently matured enough to warrant serious engineering applications. The integration of this new technology with software systems for engineering, design, and manufacturing will provide a new boost to the field of computer-aided engineering. One aspect of design and manufacturing which may be significantly affected by virtual reality is design for assembly. This paper presents a research effort aimed at creating a virtual assembly design environment. Copyright (C) 1997 Elsevier Science Ltd. C1 NATL INST STAND & TECHNOL,MFG SYST INTEGRAT DIV,GAITHERSBURG,MD 20899. RP Jayaram, S (reprint author), WASHINGTON STATE UNIV,SCH MECH & MAT ENGN,PULLMAN,WA 99164, USA. NR 16 TC 163 Z9 197 U1 7 U2 31 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0010-4485 J9 COMPUT AIDED DESIGN JI Comput.-Aided Des. PD AUG PY 1997 VL 29 IS 8 BP 575 EP 584 DI 10.1016/S0010-4485(96)00094-2 PG 10 WC Computer Science, Software Engineering SC Computer Science GA XW829 UT WOS:A1997XW82900005 ER PT J AU Mann, DA BowersAltman, J Rountree, RA AF Mann, DA BowersAltman, J Rountree, RA TI Sounds produced by the striped cusk-eel Ophidion marginatum (Ophidiidae) during courtship and spawning SO COPEIA LA English DT Article ID CYNOSCION-NEBULOSUS; POGONIAS-CROMIS C1 NEW JERSEY DIV FISH GAME & WILDLIFE ENDANGERED,TRENTON,NJ 08625. NOAA,NATL MARINE FISHERIES SERV,WOODS HOLE,MA 02543. RP Mann, DA (reprint author), UNIV MARYLAND,DEPT ZOOL,COLLEGE PK,MD 20742, USA. NR 12 TC 38 Z9 40 U1 0 U2 6 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS BUSINESS OFFICE PI CARBONDALE PA SOUTHERN ILLINOIS UNIV, DEPT ZOOLOGY, CARBONDALE, IL 62901-6501 SN 0045-8511 J9 COPEIA JI Copeia PD AUG 1 PY 1997 IS 3 BP 610 EP 612 DI 10.2307/1447568 PG 3 WC Zoology SC Zoology GA XQ307 UT WOS:A1997XQ30700015 ER PT J AU Dufaux, DP Zachariah, MR AF Dufaux, DP Zachariah, MR TI Aerosol mineralization of chlorofluorocarbons by sodium vapor reduction SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID FLAME AB This paper describes a new method for the destruction of chlorofluorocarbons (CFCs). The process consists of mixing vapor-phase CFCs and sodium at atmospheric pressure in an exothermic single-pass process leading to the mineralization of the carbon and halogen components. The process has demonstrated high destruction efficiencies for a surrogate CFC (CF4) as well as high efficiency for the formation of the equilibrium-predicted products of reaction: benign salt-coated carbon aerosols, large enough to be filtered with existing filtering technologies, with no volatile products. The rapidity of the chemistry and condensation process and the low cost of sodium should enable the construction of industrial-scale reactors that are fairly small and economical to build and operate. The application of this chemistry would be toward destruction of CFC stockpiles and as a treatment of the effluent of plasma reactors used in semiconductor processing. C1 NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. NR 17 TC 10 Z9 10 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD AUG PY 1997 VL 31 IS 8 BP 2223 EP 2228 DI 10.1021/es960882v PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XN758 UT WOS:A1997XN75800037 ER PT J AU Daskalakis, KD OConnor, TP Crecelius, EA AF Daskalakis, KD OConnor, TP Crecelius, EA TI Evaluation of digestion procedures for determining silver in mussels and oysters SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CRASSOSTREA-GIGAS THUNBERG AB Determinations of silver concentrations in mussel and oyster tissue digested with nitric acid were low relative to those measured in undigested tissue analyzed by ultrasonic graphite furnace atomic absorption spectroscopy. Good results were obtained, however, using a mixture of hydrochloric and nitric acids for digestion. Archived NOAA Mussel Watch samples collected in 1986-1993 and originally analyzed following HNO3 or HNO3-HClO4 digestion were reanalyzed with HNO3-HCl digestion in 1995. Results suggest that only 44% of the redeteremined Ag concentrations were within 20% of the original values. Most of the reanalyses yielded higher concentrations, and one-tenth of them were more than 100% higher. Temporal trends in Ag concentrations in the coastal United States have been estimated using the revised data. Statistically significant decreases, mostly in the Northeast have been observed. This is probably an indication of lower Ag discharged in waste waters. C1 NOAA,NORCA 21 NATL STATUS & TRENDS PROGRAM,SILVER SPRING,MD 20910. BATTELE,MARINE SCI LAB,SEQUIM,WA 98382. NR 14 TC 11 Z9 12 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD AUG PY 1997 VL 31 IS 8 BP 2303 EP 2306 DI 10.1021/es9608959 PG 4 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XN758 UT WOS:A1997XN75800048 ER PT J AU Short, JW Heintz, RA AF Short, JW Heintz, RA TI Identification of Exxon Valdez oil in sediments and tissues from Prince William Sound and the northwestern Gulf of Alaska based on a PAH weathering model SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article AB We used a first-order loss-rate kinetic model of polynuclear aromatic hydrocarbon (PAH) weathering to evaluate 7767 environmental samples collected for the Exxon Valdez oil spill (EVOS) for the presence of spilled oil. The model was developed from experiments with gravel coated with crude oil and washed for 6 months. The modeled PAH included the 14 most persistent compounds of 31 analyzed by GC/MS. Parameters include loss-rate constants related to the energy required for PAH to escape from petroleum and a quantitative index of weathering. The model accounts for 91% of the temporal variability of modeled PAH concentrations. We compared the discrepancies between measured and model-predicted PAH concentrations of EVOS samples with a probability distribution of these discrepancies derived from the experimental weathering results, Only 1541 field samples contained sufficient PAH for valid application of the model; three-fourths fit the model at alpha greater than or equal to 0.01 type I error, 9% fit an alternate model characterized by the absence of weathering, 17% fit neither model, and a few fit both models. The 1164 total samples that fit the weathering model account for 86% of the summed PAH concentrations detected in all 7767 samples. We conclude that first-order loss-rate kinetics account for the dominant PAH weathering processes in the EVOS and that the rate of weathering is determined mainly by the ratio of surface area to volume of petroleum in the environment. RP Short, JW (reprint author), NOAA,ALASKA FISHERIES SCI CTR,NATL MARINE FISHERIES SERV,11305 GLACIER HIGHWAY,JUNEAU,AK 99801, USA. NR 33 TC 96 Z9 96 U1 0 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD AUG PY 1997 VL 31 IS 8 BP 2375 EP 2384 DI 10.1021/es960985d PG 10 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XN758 UT WOS:A1997XN75800059 ER PT J AU Mann, FM Cheng, ET Wasson, O Chadwick, MB Young, PG Fischer, U Oyama, Y Forrest, RA AF Mann, FM Cheng, ET Wasson, O Chadwick, MB Young, PG Fischer, U Oyama, Y Forrest, RA TI Summary report on the 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics - Del Mar '95 SO FUSION ENGINEERING AND DESIGN LA English DT Editorial Material C1 TSI RES INC,SOLANA BEACH,CA. NIST,GAITHERSBURG,MD 20899. LOS ALAMOS NATL LAB,LOS ALAMOS,NM. FZK,KARLSRUHE,GERMANY. JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. UNITED KINGDOM ATOM ENERGY AUTHOR,ABDINGTON,ENGLAND. RP Mann, FM (reprint author), WESTINGHOUSE HANFORD CO,RICHLAND,WA 99352, USA. NR 2 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 1 EP 7 DI 10.1016/S0920-3796(97)00026-4 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500001 ER PT J AU Haight, RC Bateman, FB Grimes, SM Brient, CE Massey, TN Wasson, OA Carlson, AD Zhou, H AF Haight, RC Bateman, FB Grimes, SM Brient, CE Massey, TN Wasson, OA Carlson, AD Zhou, H TI Measurement of the angular distribution of neutron-proton scattering at 10 MeV SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics CY DEC 04-06, 1995 CL DEL MAR, CA SP Int Atom Energy Agcy, Nucl Data Sect DE ENDF/B-VI angular distribution; neutron-proton scattering; Arndt phase shifts ID NUCLEON AB The relative angular distribution of neutrons scattered from protons was measured at an incident neutron energy of 10 MeV at the Ohio University Accelerator Laboratory. An array of 11 detector telescopes at laboratory angles of 0-60 degrees was used to detect recoil protons from neutron interactions with a CH2 target. Data for seven of these telescopes were obtained with one set of electronics and are presented here. These data, from 108 to 180 degrees for the center-of-mass scattering angles, have a small slope which agrees better with angular distributions predicted by the Arndt phase shifts than with the ENDF/B-VI angular distribution. (C) 1997 Elsevier Science S.A. C1 OHIO UNIV,ATHENS,OH 45701. NIST,GAITHERSBURG,MD 20899. BEIJING NORMAL UNIV,BEIJING 100875,PEOPLES R CHINA. RP Haight, RC (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 11 TC 3 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 49 EP 56 DI 10.1016/S0920-3796(97)00030-6 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500006 ER PT J AU Haight, RC Bateman, FB Sterbenz, SM Grimes, SM Wasson, OA MaierKomor, P Vonach, H AF Haight, RC Bateman, FB Sterbenz, SM Grimes, SM Wasson, OA MaierKomor, P Vonach, H TI An update on (n,charged particle) research at WNR SO FUSION ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 2nd International Workshop on Nuclear Data for Fusion Reactor Technology and Related Topics CY DEC 04-06, 1995 CL DEL MAR, CA SP Int Atom Energy Agcy, Nucl Data Sect DE alpha-particles; LANSCE; neutron-induced reactions ID HELIUM PRODUCTION; NEUTRONS; ISOTOPES; NICKEL; COPPER; IRON AB Neutron-induced reactions producing light charged particles continue to be investigated at the spallation fast-neutron source at the Los Alamos Neutron Science Center (LANSCE). New data on the cross sections for alpha-particle production for neutrons on Ni-58 and Ni-60 are presented from threshold to 50 MeV. Recent changes in the experiment now allow protons, deuterons, tritons, He-3 and alpha-particles to be identified. (C) 1997 Elsevier Science S.A. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. OHIO UNIV,ATHENS,OH 45701. NIST,GAITHERSBURG,MD 20899. TECH UNIV MUNICH,D-8000 MUNICH,GERMANY. INST RADIUMFORSCH & KERNPHYS,A-1090 VIENNA,AUSTRIA. NR 19 TC 3 Z9 3 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD AUG PY 1997 VL 37 IS 1 BP 73 EP 77 DI 10.1016/S0920-3796(97)00033-1 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA YA835 UT WOS:A1997YA83500009 ER PT J AU Mackie, RL Livelybrooks, DW Madden, TR Larsen, JC AF Mackie, RL Livelybrooks, DW Madden, TR Larsen, JC TI A magnetotelluric investigation of the San Andreas fault at Carrizo Plain, California SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STATIC SHIFT; DISTORTION; REMOVAL; BASIN AB High quality, wide-band magnetotelluric data, were collected along two profiles crossing the San Andreas fault at Carrizo Plain, California for crustal imaging as part of the San Andreas Deep Drilling Project. Two-dimensional inversions of the data indicate that the upper crustal part of the San Andreas fault does not appear here as an anomalously conductive zone. Additionally, a broad resistive zone under the Temblor Mountains (east of the fault) suggests resistive crystalline or metamorphic rocks may be present here as opposed to the more conducting Franciscan assemblage, contradicting the generally-accepted geologic model. C1 UNIV OREGON,DEPT PHYS,EUGENE,OR 97403. MIT,EARTH RESOURCES LAB,CAMBRIDGE,MA 02139. NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. RP Mackie, RL (reprint author), INDIANA UNIV,DEPT GEOL SCI,BLOOMINGTON,IN 47405, USA. NR 24 TC 34 Z9 35 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 1 PY 1997 VL 24 IS 15 BP 1847 EP 1850 DI 10.1029/97GL01604 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XP337 UT WOS:A1997XP33700002 ER PT J AU Barnes, JE Hofmann, DJ AF Barnes, JE Hofmann, DJ TI Lidar measurements of stratospheric aerosol over Mauna Loa Observatory SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PINATUBO AB Dual-wavelength aerosol lidar backscatter measurements at Mauna Loa Observatory are used to monitor and characterize the 15-30 km stratospheric aerosol layer. The decay of aerosol loading following the El Chichon, Mexico (17 degrees N) and Pinatubo, Philippine Islands (15 degrees N) volcanic eruptions of 1982 and 1991, respectively, depends on the phase of the quasibiennial oscillation (QBO) in tropical stratospheric winds. Averaged over a 3-year period, these effects are removed and an exponential decay with a characteristic (e(-1)) decay time of about 1 year is observed for both eruptions. By the end of 1996, about 5 1/2 years after the Pinatubo eruption, stratospheric aerosol levels at Mauna Loa had decayed to pre-eruption levels, approximately matching the lowest aerosol levels seen here in the past 17 years (about 6 x 10(-5) sr(-1) at 694 nm integrated between 15.8 and 33 km). However, this background stratospheric aerosol level at Mauna Loa may depend on the QBO, being slightly lower during the westerly phase. Analyses of aerosol backscatter, backscatter wavelength dependence, and trajectories provide evidence for a minor injection of aerosol from the Rabaul eruption in Papua, New Guinea (4 degrees S) in September of 1994. C1 MAUNA LOA OBSERV,HILO,HI 96721. RP Barnes, JE (reprint author), NOAA,CLIMATE MONITORING & DIAGNOST LAB,R E CG,325 BROADWAY,BOULDER,CO 80303, USA. NR 11 TC 67 Z9 67 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 1 PY 1997 VL 24 IS 15 BP 1923 EP 1926 DI 10.1029/97GL01943 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XP337 UT WOS:A1997XP33700021 ER PT J AU Waltrip, BC Oldham, NM AF Waltrip, BC Oldham, NM TI Wideband wattmeter based on RMS voltage measurements SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE binary inductive voltage divider; buffer amplifier; digital voltmeter (DVM); law of cosines; power; three-voltmeter method; wattmeter AB A wideband wattmeter for measuring active power over a frequency range of de to 500 kHz is described. The wattmeter is based on the three-voltmeter method in which three rms voltage measurements are used to calculate power, The wattmeter active power uncertainty is estimated to be within 0.03% from de to 20 kHz and within 1.5% to 500 kHz. RP Waltrip, BC (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 8 TC 7 Z9 8 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9456 EI 1557-9662 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD AUG PY 1997 VL 46 IS 4 BP 781 EP 783 DI 10.1109/19.650772 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA YB638 UT WOS:A1997YB63800008 ER PT J AU Souders, TM Waltrip, BC Laug, OB AF Souders, TM Waltrip, BC Laug, OB TI Wideband sampling voltmeter SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE broadband; error analysis; signal sampling; timing; voltage measurement; voltmeter AB A high-accuracy sampling voltmeter, designed to span the frequency range of 10 Hz-200 MHz, is described, The instrument operates autonomously, at a measurement update rate of at least one per second, A novel quasiequivalent time sampling process is used, with a custom strobed comparator as the sampling device and decision element, The architecture and control are presented, along with the time-base design principles, Major error sources associated with the time-base are also discussed. RP Souders, TM (reprint author), NATL INST STAND & TECHNOL,US DEPT COMMERCE,TECHNOL ADM,GAITHERSBURG,MD 20899, USA. NR 7 TC 19 Z9 19 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD AUG PY 1997 VL 46 IS 4 BP 947 EP 953 DI 10.1109/19.650806 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA YB638 UT WOS:A1997YB63800042 ER PT J AU DeWit, R AF DeWit, R TI Diffraction elastic constants of a cubic polycrystal SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article AB New expressions for the diffraction elastic constants are presented for a cubic polycrystal that is statistically homogeneous, isotropic and disordered. The results are an extension of the theory of statistical continuum mechanics and differ from a previous derivation given by Bollenrath, Hauk, & Muller [Z. Metallkde (1967), 58, 76-82]. RP DeWit, R (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 5 TC 21 Z9 21 U1 0 U2 9 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD AUG 1 PY 1997 VL 30 BP 510 EP 511 DI 10.1107/S0021889896012812 PN 4 PG 2 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA XW118 UT WOS:A1997XW11800014 ER PT J AU Gupta, S McNider, RT Trainer, M Zamora, RJ Knupp, K Singh, MP AF Gupta, S McNider, RT Trainer, M Zamora, RJ Knupp, K Singh, MP TI Nocturnal wind structure and plume growth rates due to inertial oscillations SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID 4-DIMENSIONAL DATA ASSIMILATION; PLANETARY BOUNDARY-LAYER; NUMERICAL-MODELS; SIMULATION; DISPERSION; TRANSPORT; BREEZES; SEA AB Theoretical plume growth rates depend upon the atmospheric spatial energy spectrum. Current grid-based numerical models generally resolve large-scale (synoptic) energy, while planetary boundary layer turbulence is parameterized. Energy at intermediate scales is often neglected. In this study, boundary layer radar profilers are used to examine the temporal energy spectrum, which can provide information about the atmospheric structure affecting plume growth rates. A boundary layer model (BLM) into which the radar information has been assimilated is used to drive a Lagrangian particle model (LPM) that is subsequently employed to examine plume growth rates. Profiler and aircraft data taken during the 1995 Southern Oxidants Study in Nashville, Tennessee, are used in the model study for assimilation and evaluation. The results show that the BLM without assimilation significantly underestimates the strength of the diurnal-inertial spectral peak, which in turn causes an underestimate of plume spread. Comparison with measures of plume width from aircraft data also shows that assimilation of radar information greatly improves plume spread rates predicted by the LPM. C1 NOAA,AERON LAB,BOULDER,CO 80303. NOAA,ENVIRONM TECHNOL LAB,BOULDER,CO 80303. UNIV ALABAMA,DEPT ATMOSPHER SCI,HUNTSVILLE,AL 35899. RP Gupta, S (reprint author), UNIV ALABAMA,DEPT ATMOSPHER SCI,HUNTSVILLE,AL 35899, USA. RI Trainer, Michael/H-5168-2013 NR 34 TC 21 Z9 23 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD AUG PY 1997 VL 36 IS 8 BP 1050 EP 1063 DI 10.1175/1520-0450(1997)036<1050:NWSAPG>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN978 UT WOS:A1997XN97800010 ER PT J AU Atkinson, DG Bailey, DT Irwin, JS Touma, JS AF Atkinson, DG Bailey, DT Irwin, JS Touma, JS TI Improvements to the EPA Industrial Source Complex dispersion model SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID DEPOSITION; PARTICLE AB Air quality models are a key component in determining air pollution control requirements. The Industrial Source Complex (ISC2) model is a steady-state Gaussian plume model that is used for modeling point, area, volume, and line sources. Since its development in the 1970s by the U.S. Environmental Protection Agency, this widely used model has undergone several updates as state-of-the science techniques have become available. Some of the recent modifications to the ISC2 model include a numerically efficient area-source algorithm tested in wind tunnel experiments, a dry-deposition algorithm that can account for a full range of particle she distributions, an algorithm for calculating wet-deposition flux using the scavenging coefficient approach, and an algorithm for modeling open-pit sources. These modifications, which are part of the current ISCST3 model, are described in detail within this paper. In addition, a plume depletion model demonstration was performed to compare observed and estimated crosswind integrated concentrations of a depositing tracer as functions of travel time and stability. RP Atkinson, DG (reprint author), US EPA,ATMOSPHER SCI MODELING DIV,ARL,NOAA,MD14,RES TRIANGLE PK,NC 27711, USA. NR 19 TC 4 Z9 4 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD AUG PY 1997 VL 36 IS 8 BP 1088 EP 1095 DI 10.1175/1520-0450(1997)036<1088:ITTEIS>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN978 UT WOS:A1997XN97800013 ER PT J AU Schwede, DB Paumier, JO AF Schwede, DB Paumier, JO TI Sensitivity of the Industrial Source Complex model to input deposition parameters SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID PRECIPITATION AB The Industrial Source Complex model has recently been revised to include algorithms for estimating dry and wet deposition of particles in addition to air concentration. This study examines the sensitivity of the maximum model predictions to changes in input parameters controlling deposition, such as the shape of the particle size distribution, resolution of the size distribution, and scavenging coefficients. The modeled deposition values are more sensitive than the concentrations to changes in these parameters. The model is particularly sensitive to the use of the plume depletion option, with deposition values lowered by up to 40% when the depletion option is selected. Changes in the specification of the particle size distribution affected the highest deposition values by as much as 25%. Neither concentration nor deposition seem particularly sensitive to the use of gridded terrain data. C1 NOAA,AIR RESOURCES LAB,ATMOSPHER SCI MODELING DIV,RES TRIANGLE PK,NC. PACIFIC ENVIRONM SERV INC,RES TRIANGLE PK,NC. NR 12 TC 12 Z9 12 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD AUG PY 1997 VL 36 IS 8 BP 1096 EP 1106 DI 10.1175/1520-0450(1997)036<1096:SOTISC>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN978 UT WOS:A1997XN97800014 ER PT J AU Lee, RF Irwin, JS AF Lee, RF Irwin, JS TI Improving concentration measures used for evaluating air quality models SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article AB An unfortunate difficulty in model evaluation is that the concentration measure that most models predict, namely the ensemble mean concentration under the plume centerline (or at some location relative to the plume centerline), cannot be measured directly. The problem can be ameliorated by judicious selection of a concentration measure against which to compare model predictions. Insufficient attention has been given in the past to the selection of an appropriate measure for use in air quality model evaluation studies, which may have resulted in biases in the results of those studies. Some studies have used the maximum concentrations along the arc (arc maximum) as the measure of choice. In this paper, the authors have considered two additional candidate measures, the fitted maximum concentrations and the near-centerline concentrations, which, intuitively, relate more closely to the ensemble mean concentrations. This study shows that the maximum concentrations along the arc are significantly higher than either the fitted maxima or the near-centerline concentrations. In addition, of the latter two measures, the authors conclude that use of the near-centerline concentration is preferable to the use of fitted maximum for the purposes of evaluating model performance. RP Lee, RF (reprint author), US EPA,MD 14,NOAA,ARL,ATMOSPHER SCI MODELING DIV,RES TRIANGLE PK,NC 27711, USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD AUG PY 1997 VL 36 IS 8 BP 1107 EP 1112 DI 10.1175/1520-0450(1997)036<1107:ICMUFE>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN978 UT WOS:A1997XN97800015 ER PT J AU Zhang, NF AF Zhang, NF TI Detection capability of residual control chart for stationary process data SO JOURNAL OF APPLIED STATISTICS LA English DT Article ID STATISTICAL PROCESS-CONTROL; AUTOCORRELATED DATA AB In recent years, methods for dealing with autocorrelated data in the statistical process control environment have been proposed. A primary method is based on modeling the process data and applying control charts to the residuals. However, the residual charts do not have the same properties as the traditional charts. In the literature, there has been no systematic study on the detection capability of the residual chart for the stationary processes. The article develops a measure of the detection capability of the residual chart for the general stationary processes. Conditions under which the residual chart reduces or increases the detection capability are given. The relationships between the detection capability and the average run length of the residual chart are also established. C1 NIST,STAT ENGN DIV,GAITHERSBURG,MD 20899. NR 11 TC 18 Z9 22 U1 0 U2 0 PU CARFAX PUBL CO PI ABINGDON PA PO BOX 25, ABINGDON, OXFORDSHIRE, ENGLAND OX14 3UE SN 0266-4763 J9 J APPL STAT JI J. Appl. Stat. PD AUG PY 1997 VL 24 IS 4 BP 475 EP 492 PG 18 WC Statistics & Probability SC Mathematics GA YE655 UT WOS:A1997YE65500008 ER PT J AU Mikhin, DY Godin, OA Boebel, O Zenk, W AF Mikhin, DY Godin, OA Boebel, O Zenk, W TI Simulations of acoustic imprints of meddles in the Iberian Basin: Toward acoustic detection of meddles SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID MEDITERRANEAN WATER; MOVING-MEDIA; SOUND; ATLANTIC; LENSES; FIELDS; OCEAN; CURRENTS; MEDDIES AB Ocean currents' effect on long-range sound propagation, though considerable in many cases, is difficult to separate from much stronger effects due to sound speed inhomogeneities, as flow velocity is usually much smaller than typical variations in the sound speed. Dramatic improvement can be achieved in reciprocal transmission experiments when sound signals propagate in opposite directions between two transceivers (source-receiver pairs). The presence of a current results in the breaking of the principle of acoustic reciprocity, thus making it possible to use nonreciprocity of acoustic field as an indicator of water movement. In this paper, reciprocal acoustic transmissions through a submesoscale interthermocline lens of Mediterranean Water (meddy) in the Atlantic are considered theoretically as a possible tool for meddles detection. A simple model of acoustic ray-travel-time nonreciprocity due to a meddy is proposed. The analytic estimates obtained from the model show that the influence of rotary flow is more important than that of drift and seems to be measurable. The problem is studied in more detail via computer simulations. The environmental model used in the simulations corresponds to case studies performed in the Iberian Basin in 1989 and 1991. Numerical simulations show that travel times between two transceivers can be gathered into several groups; for the most part, rays in each set have similar geometry for both propagation directions. However, the lens strongly affects the number of rays in each group, their launch angles, and number of surface interactions, making it impossible to identify these arrivals as required for conventional ocean acoustic tomography. In spite of complexity of ray structure, travel-time nonreciprocity predicted by the model proposed is in good agreement with numerical results. This fact suggests that the model could be used to estimate some parameters of a meddy. C1 NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33149. UNIV VICTORIA,SCH EARTH & OCEAN SCI,VICTORIA,BC V8W 2Y2,CANADA. RUSSIAN ACAD SCI,PP SHIRSHOV OCEANOL INST,ACOUST WAVE PROPAGAT LAB,MOSCOW,RUSSIA. CHRISTIAN ALBRECHTS UNIV KIEL,INST MEERESKUNDE,ABT MEERESPHYS,KIEL,GERMANY. RI Godin, Oleg/E-6554-2011 OI Godin, Oleg/0000-0003-4599-2149 NR 41 TC 6 Z9 6 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD AUG PY 1997 VL 14 IS 4 BP 938 EP 949 DI 10.1175/1520-0426(1997)014<0938:SOAIOM>2.0.CO;2 PG 12 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XN532 UT WOS:A1997XN53200015 ER PT J AU Hoerling, MP Kumar, A Zhong, M AF Hoerling, MP Kumar, A Zhong, M TI El Nino, La Nina, and the nonlinearity of their teleconnections SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; EXTRATROPICAL RESPONSE; SOUTHERN OSCILLATION; NORTHERN WINTER; PACIFIC; ORGANIZATION; ATMOSPHERE; TRANSIENTS; ANOMALIES; MODELS AB The paradigm of an atmospheric system varying linearly with respect to extreme phases of the EI Nino-Southern Oscillation is questioned. It is argued that the global response to tropical Pacific sea surface temperature forcing will be inherently nonlinear. A physical basis far this intrinsic nonlinearity is the thermodynamic control on deep convection. Climate statistics for warm and cold events of the tropical Pacific are analyzed separately for the northern winter periods during 1950-96. Composite analysis of 500-mb heights reveal planetary-scale teleconnection patterns, as noted in earlier studies. A new result is the evidence for an appreciable 35 degrees longitude phase shift between the warm and cold event circulation composites, and the two wave trains appear to have different tropical origins. A large nonlinear component in North American surface climate anomalies is also found, which is consistent with such a phase shift in teleconnections. In the Tropics, rainfall anomalies also show evidence of nonlinear behavior. The maximum rain anomalies along the equator are located east of the date line during warm events, but west of the date line during cold events. The interpretation of this behavior is complicated, however, by the fact that composite warm event SST anomalies are not the exact inverse of their cold event counterparts. Idealized atmospheric general circulation model (AGCM) experiments are performed in order to test the question of whether the observed nonlinearity is an intrinsic property of the atmospheric system. The model is forced with a composite SST anomaly that undergoes a realistic seasonally varying ENSO life cycle, as described by E. Rasmusson and T. Carpenter. Both positive and negative phases of the SST anomaly are used, and a 40-member ensemble of warm and cold event model simulations is conducted. A nonlinear climate response in the AGCM is found that closely resembles the observed composites, including a shift in the equatorial positions of the maxmium rain responses and a phase shift of teleconnection patterns in the upper troposphere. Barotropic model experiments indicate that the inherent nonlinearity in the tropical rain response may itself be responsible for the phase shift in the extratropical teleconnection patterns. C1 NOAA,NCEP,WASHINGTON,DC. RP Hoerling, MP (reprint author), UNIV COLORADO,CDC,CIRES,BOULDER,CO 80309, USA. RI yu, yan/C-2322-2012 NR 33 TC 468 Z9 485 U1 9 U2 75 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD AUG PY 1997 VL 10 IS 8 BP 1769 EP 1786 DI 10.1175/1520-0442(1997)010<1769:ENOLNA>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU085 UT WOS:A1997XU08500001 ER PT J AU Livezey, RE Masutani, M Leetmaa, A Rui, H Ji, M Kumar, A AF Livezey, RE Masutani, M Leetmaa, A Rui, H Ji, M Kumar, A TI Teleconnective response of the Pacific-North American region atmosphere to large central equatorial Pacific SST anomalies SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURES; SOUTHERN OSCILLATION; CIRCULATION PATTERNS; HEMISPHERE WINTER; CLIMATE; SKILL; PRECIPITATION; VERIFICATION; VARIABILITY; FIELD AB A prominent year-round ensemble response to a global sea surface temperature (SST) anomaly held fixed to that for January 1992 (near the peak of a major warm El Nino-Southern Oscillation episode) was observed in a 20-yr integration of the general circulation model used for operational seasonal prediction by the U.S. National Weather Service. This motivated a detailed observational reassessment of the teleconnections between strong SST anomalies in the central equatorial Pacific Ocean and Pacific-North America region 700-hPa heights and U.S. surface temperatures and precipitation. The approach used consisted of formation of monthly mean composites formed separately from cases in which the SST anomaly in a key area of the central equatorial Pacific Ocean was either large and positive or Large and negative. Extensive permutation tests were conducted to test null hypotheses of no signal in these composites. The results provided a substantial case for the presence of teleconnections to either the positive-or negative-SST anomalies in every month of the year. These signals were seasonally varying (sometimes with substantial month to month changes) and, when present for both SST-anomaly signs in a particular month, usually were not similarly phased patterns of opposite polarity (i.e., the SST-teleconnected variable relationships were most often nonlinear). A suite of 13 45-yr integrations of the same model described above was run with global SST analyses reconstructed from the observational record. Corresponding composites from the model were formed and compared visually and quantitatively with the high-confidence observational signals. The quantitative comparisons included skill analyses utilizing a decomposition that relates the squared differences between two maps to phase correspondence and amplitude and bias error terms and analyses of the variance about composite means. For the latter, in the case of the model runs it was possible to estimate the portions of this variance attributable to case to case variation in SSTs and to internal variability. Comparisons to monthly mean maps and analyses of variance for the 20-yr run with SSTs fixed to January 1992 Values were also made. The visual and quantitative comparisons all revealed different aspects of prominent model systematic errors that have important implications for the optimum exploitation of the model for use in prediction. One of these implications was that the current model's ensemble responses to SST forcing will not be optimally useful until after nonlinear correction of SST-field-dependent systematic errors. C1 RES & DATA SYST CORP,GREENBELT,MD. NOAA,NCEP,NWS,ENVIRONM MODELING CTR,WASHINGTON,DC 20233. RP Livezey, RE (reprint author), NOAA,NCEP,NWS,CLIMATE PREDICT CTR,WASHINGTON,DC 20233, USA. NR 30 TC 118 Z9 119 U1 1 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD AUG PY 1997 VL 10 IS 8 BP 1787 EP 1820 DI 10.1175/1520-0442(1997)010<1787:TROTPN>2.0.CO;2 PG 34 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU085 UT WOS:A1997XU08500002 ER PT J AU Klein, SA AF Klein, SA TI Synoptic variability of low-cloud properties and meteorological parameters in the subtropical trade wind boundary layer SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; TO-CUMULUS TRANSITION; NUMERICAL-SIMULATION; RELATIVE-HUMIDITY; STRATOCUMULUS; MODEL; SCHEME; CIRCULATION; SATELLITE; ASTEX AB Synoptic variability of low-cloud properties, temperature advection, and thermodynamic soundings of the trade wind boundary layer are analyzed, using the long data record from ocean weather station November (30 degrees N, 140 degrees W). The variations in low-cloud amount at this subtropical site are most strongly correlated with variations in temperature advection. the stability of the lower troposphere, and the relative humidity of the cloud layer. No single predictor is capable of explaining more than 13% of the variance in low-cloud amount. However, the amount of variance explained increases considerably when the data are averaged over several days. Four parameterizations for the amount of stratiform cloud under a subsidence inversion are tested against the observed amount of low clouds. The four parameterizations are based upon relative humidity. the inversion strength, a muting line slope, and the amount of condensed water. All parameterizations are positively correlated with the observed cloud amounts, although the variance explained is less than 16%. RP PRINCETON UNIV, NOAA, GODDARD FLUID DYNAM LAB, PROGRAM ATMOSPHER & OCEAN SCI, PO 308, PRINCETON, NJ 08542 USA. RI Klein, Stephen/H-4337-2016 OI Klein, Stephen/0000-0002-5476-858X NR 55 TC 61 Z9 63 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD AUG PY 1997 VL 10 IS 8 BP 2018 EP 2039 DI 10.1175/1520-0442(1997)010<2018:SVOLCP>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XU085 UT WOS:A1997XU08500014 ER PT J AU Bryan, K AF Bryan, K TI A numerical method for the study of the circulation of the world ocean (Reprinted from the Journal of Computational Physics, vol 4, pg 347-376, 1969) SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Reprint AB A model is presented for studying ocean circulation problems taking into account the complicated outline and bottom topography of the World Ocean, To obtain an efficient scheme for the study of low-frequency, large-scale current systems, surface gravity-inertial waves are filtered out by the ''rigid-lid'' approximation. To resolve special features of the ocean circulation, such as the Equatorial Undercurrent, the numerical model allows for a variable spacing in either the zonal or meridional direction, The model is designed to be as consistent as possible with the continuous equations with respect to energy. It is demonstrated that no fictitious energy generation or decay is associated with the nonlinear terms in the finite difference form of the momentum equations. The energy generation by buoyancy forces for the numerical model is also designed in such a way that no energy ''leak'' occurs in the transformation from potential to kinetic energy. (C) 1969 Academic Press. RP Bryan, K (reprint author), ESSA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08540 USA. NR 20 TC 7 Z9 7 U1 1 U2 4 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 AUG PY 1997 VL 135 IS 2 BP 154 EP 169 DI 10.1006/jcph.1997.5699 PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XQ327 UT WOS:A1997XQ32700012 ER PT J AU Coriell, SR Mitchell, WF Murray, BT Andrews, JB Arikawa, Y AF Coriell, SR Mitchell, WF Murray, BT Andrews, JB Arikawa, Y TI Analysis of monotectic growth: infinite diffusion in the L-2 phase SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE monotectic; aluminum-indium; eutectic; diffusion ID LAMELLAR EUTECTIC GROWTH; LARGE THERMAL-GRADIENT; IMMISCIBLE ALLOYS; AL-IN; SOLIDIFICATION; SYSTEMS AB The Jackson-Hunt model of eutectic solidification is applied to monotectic solidification in which a liquid (L-1) transforms into rods of a different liquid (L-2) in a solid matrix. Limiting cases of no diffusion and infinite diffusion (complete mixing) in the L-2 phase are considered. An adaptive refinement and multigrid algorithm (MGGHAT) is used to obtain numerical solutions for the concentration field in the L-1 phase; this allows consideration of a general phase diagram. Density differences between the three phases, which cause fluid flow, are treated approximately. Specific calculations are carried out for aluminum-indium alloys. Infinite diffusion in the L-2 phase has only a small effect on the relationship between interface undercooling and rod spacing. C1 UNIV ALABAMA,DEPT MAT SCI & ENGN,BIRMINGHAM,AL 35294. RP Coriell, SR (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 34 TC 22 Z9 23 U1 2 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 AUG PY 1997 VL 179 IS 3-4 BP 647 EP 657 DI 10.1016/S0022-0248(97)00177-2 PG 11 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA XT429 UT WOS:A1997XT42900040 ER PT J AU Peterson, ME Pelroy, GA Poysky, FT Paranjpye, RN Dong, FM Pigott, GM Eklund, MW AF Peterson, ME Pelroy, GA Poysky, FT Paranjpye, RN Dong, FM Pigott, GM Eklund, MW TI Heat-pasteurization process for inactivation of nonproteolytic types of Clostridium botulinum in picked dungeness crabmeat SO JOURNAL OF FOOD PROTECTION LA English DT Article DE Clostridium botulinum; Dungeness crab; heat pasteurization ID BLUE-CRAB; LISTERIA-MONOCYTOGENES; RESISTANCE; SPORES; MEAT AB Development of a heat-pasteurization process is described for picked meat of Dungeness crabs (Cancer magister) contained in oxygen-impermeable flexible pouches. For each time-temperature treatment, 30 samples, each inoculated with an equal mixture of three strains of C. botulinum nonproteolytic type B, for a total of 10(7) spores, provided the basis for calculation of the thermal resistance (a 70 process). Following heat processing, the crabmeat was removed from the pouches and transferred to enrichment medium where it was incubated anaerobically for 150 days. Endpoints at which spores survived were determined by the presence of toxin in the enrichment medium. Process times ranged from 90 min at 88.9 degrees C to 20.3 min at 94.4 degrees C. D values (the time at each temperature required to reduce the inoculum by 1 log) ranged from 12.9 for the 88.9 degrees C process to 2.9 for the 94.4 degrees C process. The relative sterilization value, F-0, was .054 and the pasteurization value, F-185(16) was 240. This pasteurization process safely extends refrigerated shelf life by inactivating spores of Clostridium botulinum nonproteolytic types B, E, and F and also non-spore-forming pathogens such as Listeria monocytogenes. The process does not, however, inactivate the heat-resistant proteolytic strains of C. botulinum or other more heat-resistant spore-formers. The packages and master cartons of the pasteurized product, therefore, should be labeled ''Keep refrigerated-Continuous refrigeration below 38 degrees F (3.3 degrees C) required.'' C1 UNIV WASHINGTON,SCH FISHERIES,INST FOOD SCI & TECHNOL,SEATTLE,WA 98105. RP Peterson, ME (reprint author), NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES CTR,US DEPT COMMERCE,UTILIZATION RES DIV,SEATTLE,WA 98112, USA. NR 32 TC 15 Z9 15 U1 2 U2 9 PU INT ASSOC MILK FOOD ENVIRONMENTAL SANITARIANS, INC PI DES MOINES PA 6200 AURORA AVE SUITE 200W, DES MOINES, IA 50322-2838 SN 0362-028X J9 J FOOD PROTECT JI J. Food Prot. PD AUG PY 1997 VL 60 IS 8 BP 928 EP 934 PG 7 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA XT095 UT WOS:A1997XT09500009 ER PT J AU Govoni, JJ AF Govoni, JJ TI The association of the population recruitment of gulf menhaden, Brevoortia patronus, with Mississippi River discharge SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT 27th International Liege Colloguium on Ocean Hydrodynamics CY MAY 08-12, 1995 CL LIEGE, BELGIUM SP Minist Educ & Res, Belgium, Natl Sci Bdn Belgium, Univ Liege, ICSU, Sci Comm Oceanog Res, Int Assoc Phys Sci Ocean, UNESCO, Intergovt Oceanog Commiss, European Union, USN, Off Naval Res, Natl Sci Fdn, US DE recruitment; river discharge; cross-shelf transport ID SPATIAL-DISTRIBUTION; CONTINENTAL-SHELF; LARVAL FISHES; NORTHERN GULF; FRESH-WATER; TEXAS SHELF; PLUME; LOUISIANA; GROWTH; MEXICO AB Gulf menhaden, Brevoortia patronus, which constitutes a major industrial reduction fishery in the USA, spawn across the northern Gulf of Mexico with a focus of spawning about the Mississippi Delta. This species is estuarine dependent; adults spawn over the continental shelf and their larvae are transported, by mechanisms that are presently not well understood, to estuarine nursery areas. Larval gulf menhaden, along with some other surface oriented larval fishes, appear to aggregate along the Mississippi River plume front, while evidence of the ecological consequences of this aggregation in terms of the feeding, growth, and survival of larvae is ambiguous. On an annual scale, Mississippi River discharge is negatively associated with numbers of half year old recruits. Discharge of the Mississippi River and the population recruitment of gulf menhaden may be plausibly linked through the action of the river's plume and its front on the shoreward transport of larvae. Greater river discharge results in an expansive plume that might project larvae farther offshore and prolong the shoreward transport of larvae. An indirect, decadal scale, positive response of recruitment and river discharge is possible, but not certain. Recruitment became elevated after 1975 when river discharge increased and became highly variable. This response might owe to enhanced primary and secondary production driven by nutrient influx from the Mississippi River. (C) 1997 Elsevier Science B.V. RP Govoni, JJ (reprint author), NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES CTR,BEAUFORT LAB,101 PIVERS ISL RD,BEAUFORT,NC 28516, USA. NR 39 TC 20 Z9 20 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD AUG PY 1997 VL 12 IS 1-4 BP 101 EP 108 DI 10.1016/S0924-7963(96)00091-7 PG 8 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA YB095 UT WOS:A1997YB09500008 ER PT J AU Hitchcock, GL Wiseman, WJ Boicourt, WC Mariano, AJ Walker, N Nelsen, TA Ryan, E AF Hitchcock, GL Wiseman, WJ Boicourt, WC Mariano, AJ Walker, N Nelsen, TA Ryan, E TI Property fields in an effluent plume of the Mississippi river SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT 27th International Liege Colloguium on Ocean Hydrodynamics CY MAY 08-12, 1995 CL LIEGE, BELGIUM SP Minist Educ & Res, Belgium, Natl Sci Bdn Belgium, Univ Liege, ICSU, Sci Comm Oceanog Res, Int Assoc Phys Sci Ocean, UNESCO, Intergovt Oceanog Commiss, European Union, USN, Off Naval Res, Natl Sci Fdn, US ID SPATIAL-DISTRIBUTION; LOUISIANA BIGHT; LARVAL FISHES; SHELF; ACCUMULATION; TEMPERATURE; CURRENTS; REGIONS; FRONTS; EXPORT AB Surface property distributions were mapped in the Mississippi River plume during May and August, 1993 while following surface drifters. Prevailing winds were the primary factor controlling the orientation of the plume. In May, under typical southeasterly winds, the plume turned anticyclonically towards the coast, while in August, under anomalous westerly winds, the plume turned east. Remote imagery of sea surface temperature and suspended sediments confirmed the direction of the plume. Optimally interpolated maps of surface salinity, temperature, chlorophyll a fluorescence, and transmissivity from underway sampling, and periodic nutrient samples, reveal the plume structure. In May concentrations of nitrate, silicate, and phosphate decreased linearly with increasing salinity. Chlorophyll a increased to peak concentrations of 10 mu g l(-1) in the plume, although higher pigment biomass was observed near the coast. In August nitrate and silicate concentrations decreased conservatively near the mouth of SW Pass, except where pigment biomass was enhanced in a convergent surface front. Surface nutrient concentrations in the plume also decreased with increasing salinity. The observations provide the first Lagrangian view of surface property distributions in the Mississippi River plume, and indicate that significant temporal variability exists in physical and biological properties within a day after waters are discharged from the river delta. (C) 1997 Elsevier Science B.V. C1 LOUISIANA STATE UNIV,INST COASTAL STUDIES,BATON ROUGE,LA 70803. UNIV MARYLAND,HORN POINT ENVIRONM LAB,CAMBRIDGE,MD 21613. NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33149. RP Hitchcock, GL (reprint author), UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MIAMI,FL 33149, USA. RI Walker, Nan/D-8819-2013 NR 40 TC 45 Z9 46 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD AUG PY 1997 VL 12 IS 1-4 BP 109 EP 126 DI 10.1016/S0924-7963(96)00092-9 PG 18 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA YB095 UT WOS:A1997YB09500009 ER PT J AU Ilavsky, J Berndt, CC Karthikeyan, J AF Ilavsky, J Berndt, CC Karthikeyan, J TI Mercury intrusion porosimetry of plasma-sprayed ceramic SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID VALIDITY; PRESSURE AB Limitations and corrections for the application of mercury intrusion porosimetry (MIP) in measuring plasma-sprayed ceramic (alumina-titania) deposits are studied. The data reduction procedures of the MIP technique are discussed; the importance of which changes between different machines and samples. Thus, it is proposed that each published result should be accompanied by the specific data reduction procedures and assumptions used so that data may be compared. Preparation of plasma-sprayed ceramic samples has a significant influence on the MIP result. Sample fragmentation into irregular pieces (below about 1.2 mm effective diameter) prior to the MIP measurement resulted in an increase of surface effects such that the surface roughness dominated the MIP data and the measured porosity volume increased. Variation in sample thickness between 0.8 and 4.7 mm did not change the measured porosity. Orientation (parallel or perpendicular to the substrate) of the flat surface did not have a measurable effect on the MIP results. C1 SUNY STONY BROOK,THERMAL SPRAY LAB,STONY BROOK,NY 11794. NATL INST STAND & TECHNOL,CERAM GRP,GAITHERSBURG,MD 20899. RI Ilavsky, Jan/D-4521-2013 OI Ilavsky, Jan/0000-0003-1982-8900 NR 21 TC 27 Z9 27 U1 1 U2 3 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD AUG 1 PY 1997 VL 32 IS 15 BP 3925 EP 3932 DI 10.1023/A:1018612815364 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA XP279 UT WOS:A1997XP27900004 ER PT J AU Hughes, RA Brown, JM Evenson, KM AF Hughes, RA Brown, JM Evenson, KM TI Rotational spectrum of the AsH radical in its a(1)Delta state, studied by far-infrared laser magnetic resonance SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID POTENTIAL-ENERGY CURVES; SPECTROSCOPY AB The rotational spectrum of AsH in ils metastable a(1) Delta state has been recorded using a far-infrared laser magnetic resonance spectrometer. The AsH radical was produced inside the spectrometer by the reaction of arsine (AsH3) with fluorine atoms. Hyperfine splitting from both As-75 and H-1 nuclei were observed, and analysis of the spectra yielded accurate values for rotational, hyperfine, and Zeeman parameters. (C) 1997 Academic Press. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. RP Hughes, RA (reprint author), PHYS & THEORET CHEM LAB,S PARKS RD,OXFORD OX1 3QZ,ENGLAND. NR 16 TC 1 Z9 1 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD AUG PY 1997 VL 184 IS 2 BP 454 EP 459 DI 10.1006/jmsp.1997.7351 PG 6 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA XY001 UT WOS:A1997XY00100024 ER PT J AU Flosadottir, AH Larsen, JC Smith, JT AF Flosadottir, AH Larsen, JC Smith, JT TI The relation of seafloor voltages to ocean transports in North Atlantic circulation models: Model results and practical considerations for transport monitoring SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID INDUCED ELECTROMAGNETIC-FIELDS; ELECTRIC-FIELD; MAGNETIC-FIELDS; LOW-FREQUENCY; SCALE; INSTRUMENT AB Motionally induced voltage differences offer one of the few observational methods sensitive to changes in large-scale ocean transports. They present a useful contrast to most oceanographic data by virtue of their natural spatial integration, temporal continuity, and potentially long duration. However, widespread oceanographic use of the voltages observable with seafloor cables has been impeded by uncertainties of interpretation. Interpretation in terms of volume transport fluctuations has proved successful in the Straits of Florida and for a short cable in the easternmost part of the Bering Strait. Still, a number of order experimental studies resulted in disappointment, the Bering Strait work has been little known, and the Florida success might be a special case. The question considered in this paper is: Does a linear relationship between net transport and voltage difference fluctuations hold for long, open-ocean cables? This question is addressed by using a numerical model based on two years of results from the WOCE Community Modeling Effort, which simulated the wind-driven and thermohaline circulation in the North Atlantic using mean monthly winds and realistic topography with a resolution sufficient to permit mesoscale eddies. The model includes the effects of spatial and temporal variations of seawater temperature and salinity, electric current loops, the effects associated with the meandering of ocean currents over realistic topography and sediment thickness, realistic earth conductivity, and the spatially varying geomagnetic field. The main result is that the relationship between voltage and net cross-cable transport fluctuations can be remarkably linear over long distances. In view of the difficulties of long-term, large-scale transport monitoring by other methods, the implication of this work is that well chosen and carefully interpreted voltage observations herd great promise. This should be explored through renewed modeling, observation, and interpretation efforts. C1 UNIV WASHINGTON,DEPT GEOPHYS,SEATTLE,WA 98195. RP Flosadottir, AH (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. NR 54 TC 12 Z9 12 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD AUG PY 1997 VL 27 IS 8 BP 1547 EP 1565 DI 10.1175/1520-0485(1997)027<1547:TROSVT>2.0.CO;2 PG 19 WC Oceanography SC Oceanography GA XT237 UT WOS:A1997XT23700005 ER PT J AU Baringer, MO Price, JF AF Baringer, MO Price, JF TI Mixing and spreading of the Mediterranean outflow SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID WATER; GIBRALTAR; STRAIT; STRESS; SEA; SHEAR; UNDERCURRENT; CIRCULATION; VARIABILITY; FREQUENCY AB Hydrographic and current profiler data taken during the 1988 Gulf of Cadiz Expedition have been analyzed to diagnose the mixing, spreading, and descent of the Mediterranean outflow. The theta-S properties and the thickness and width of the outflow were similar to that seen in earlier surveys. The transport of pure Mediterranean Water (i.e., water with S greater than or equal to 38.4 psu) was estimated to be about 0.4 x 10(6) m(3) s(-1), which is lower than historical estimates-most of which were indirect-but comparable to other recent estimates made from direct velocity observations. The outflow transport estimated at the west end of the Strait of Gibraltar was about 0.7 x 10(6) m(3) s(-1) of mixed water, and the transport increased to about 1.9 x 10(6) m(3) s(-1) within the eastern Gulf of Cadiz. This increase in transport occurred by entrainment of fresher North Atlantic Central Water, and the salinity anomaly of the outflow was consequently reduced. The velocity-weighted salinity decreased to 36.7 psu within 60 km of the strait and decreased by about another 0.1 before the deeper portion of the outflow began to separate from of the bottom near Cape St. Vincent. Entrainment appears to have been correlated spatially with the initial descent of the continental slope and with the occurrence of bulk Froude numbers slightly greater than 1. In the western Gulf of Cadiz, where entrainment was much weaker, Froude numbers were consistently well below 1. The outflow began in the eastern Strait of Gibraltar as a narrow (10 km wide) current having a very narrow range of theta-S properties. The outflow broadened as it descended the continental slope of the northern Gulf of Cadiz and reached a maximum width of 80 km in the western Gulf of Cadiz. The descent of the outflow was very asymmetric: The southern (offshore) edge of the outflow descended about 1000 m from Gibraltar to Cape St. Vincent, while the northern (onshore) edge of the outflow descended only a few hundred meters. The northern, onshore side thus remained considerably higher in the water column and thus entrained relatively warm North Atlantic Central Water. This caused the outflow to develop horizontal theta-S variability and, by about 140 km downstream, the across-stream variation in temperature on an isopycnal was more than 2 degrees C. Much of the volume transport in the western Gulf of Cadiz was contained within two preferred modes or cores. The deeper, offshore core had a central sigma(theta) = 27.8 kg m(-3), and the shallower onshore core, which was still in contact with the bottom in the Gulf of Cadiz, had a central sigma(theta) = 27.5 kg m(-3). These two cores develop as a result of the spreading and horizontally varying entrainment noted above, combined with topographic steering. C1 WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543. RP Baringer, MO (reprint author), NOAA,ATLANTIC OCEANOG & METEOROL LAB,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Baringer, Molly/D-2277-2012 OI Baringer, Molly/0000-0002-8503-5194 NR 68 TC 188 Z9 188 U1 0 U2 14 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD AUG PY 1997 VL 27 IS 8 BP 1654 EP 1677 DI 10.1175/1520-0485(1997)027<1654:MASOTM>2.0.CO;2 PG 24 WC Oceanography SC Oceanography GA XT237 UT WOS:A1997XT23700011 ER PT J AU Baringer, MO Price, JF AF Baringer, MO Price, JF TI Momentum and energy balance of the Mediterranean outflow SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID CURRENTS; STRAIT; STRESS; OCEAN; PLUME AB Field data taken in the Gulf of Cadiz have been analyzed to describe some aspects of the momentum and energy balance of the Mediterranean outflow. A crucial component of the momentum balance is the total stress (entrainment stress and bottom drag), which has been estimated from a form of the Bernoulli function evaluated from density and current observations. For the first 60 km west of the Camarinal Sill the outflow was confined within a narrow channel on the continental shelf. At about 70 km downstream the outflow crossed over the shelf-slope break and began to descend the continental slope. The buoyancy force increased substantially, and the outflow underwent a geostrophic adjustment, albeit one heavily influenced by mixing and dissipation. The current direction turned 90 degrees to the right at a near-inertial rate. In this region, the estimated geostrophic velocity greatly underestimated the actual current, and the estimated curvature Rossby number was about 0.5. Current speeds were in excess of 1 m s(-1) and the total stress was as large as 5 Pa. The entrainment stress, estimated independently from property fluxes, reached a maximum of about 1 Pa, or considerably smaller than the inferred bottom stress. By about 130 km downstream, the current was aligned approximately along the local topography. The current amplitude and the estimated stress were then much less, about 0.3 m s(-1) and 0.3 Pa. The entrainment stress was also very small in this region well downstream of the strait. This slightly damped geostrophic flow continued on to Cape St. Vincent where the outflow began to separate from the bottom. Bottom stress thus appears to be a crucial element in the dynamics of the Mediterranean outflow, allowing or causing the outflow to descend more than a kilometer into the North Atlantic. In the regions of strongest bottom stress the inferred drag coefficient was about 2 - 12 (x 10(-3)) depending upon which outflow speed is used in the usual quadratic form. Entrainment stress was small by comparison to the bottom stress, but the entrainment effect upon the density anomaly was crucial in eroding the density anomaly of the outflow. The observed entrainment rate appears to follow, roughly, a critical internal Froude number function. C1 WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543. RP Baringer, MO (reprint author), NOAA,ATLANTIC OCEANOG & METEOROL LAB,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Baringer, Molly/D-2277-2012 OI Baringer, Molly/0000-0002-8503-5194 NR 24 TC 75 Z9 75 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD AUG PY 1997 VL 27 IS 8 BP 1678 EP 1692 DI 10.1175/1520-0485(1997)027<1678:MAEBOT>2.0.CO;2 PG 15 WC Oceanography SC Oceanography GA XT237 UT WOS:A1997XT23700012 ER PT J AU Munro, RG AF Munro, RG TI Evaluated material properties for a sintered alpha-alumina SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID ELEVATED-TEMPERATURES; DUCTILE TRANSITION; CERAMICS; MECHANISM; TOUGHNESS; STRENGTH; CREEP AB Results of a data evaluation exercise are presented for a particular specification of sintered alpha-alumina (mass fraction of Al2O3, greater than or equal to 0.995; relative density (rho/rho(theoretical)), greater than or equal to 0.98; and nominal grain size, 5 mu m). A comprehensive set of material property data is established based on published physical, mechanical, and thermal properties of alumina specimens that conform to the constraints of the material specification. The criteria imposed on the properties are that the values should be derived from independent experimental studies, that the values for physically related properties should be mutually self-consistent, and that the sets of values should be compatible with established material property relations. The properties assessed in this manner include crystallography, thermal expansion, density, sound velocity, elastic modulus, shear modulus, Poisson's ratio, bulk modulus, compressive strength, flexural strength, Weibull characteristic strength, Weibull modulus, tensile strength, hardness, fracture toughness, creep rate, creep rate stress exponent, creep activation energy, friction coefficient, wear coefficient, melting point, specific heat, thermal conductivity, and thermal diffusivity. RP NIST, DIV CERAM, GAITHERSBURG, MD 20899 USA. NR 57 TC 339 Z9 355 U1 13 U2 119 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 1997 VL 80 IS 8 BP 1919 EP 1928 PG 10 WC Materials Science, Ceramics SC Materials Science GA XQ331 UT WOS:A1997XQ33100001 ER PT J AU Jorgensen, DP LeMone, MA Trier, SB AF Jorgensen, DP LeMone, MA Trier, SB TI Structure and evolution of the 22 February 1993 TOGA COARE squall line: Aircraft observations of precipitation, circulation, and surface energy fluxes SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MESOSCALE CONVECTIVE SYSTEM; 10-11 JUNE 1985; DOPPLER RADAR DATA; KINEMATIC STRUCTURE; NUMERICAL-SIMULATION; VERTICAL PROFILE; TRANSITION ZONE; MATCHING MODELS; BOUNDARY-LAYER; VORTEX COUPLET AB This study documents the precipitation and kinematic structure of a mature, eastward propagating, oceanic squall line system observed by instrumented aircraft during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). Doppler radar and low-level in situ observations are used to show the evolution of the convection from an initially linear NNW-SSE-oriented convective line to a highly bow-shaped structure with an embedded low- to midlevel counterclockwise rotating vortex on its northern flank. In addition to previously documented features of squall lines such as highly upshear-tilted convection on its leading edge, a channel of strong front-to-rear flow that ascended with height over a ''rear-inflow'' that descended toward the convective line, and a pronounced low-level cold pool apparently fed from convective and mesoscale downdrafts from the convective line; rearward, the observations of this system showed distinct multiple maxima in updraft strength with height and reflectivity bands extending rearward transverse to the principal convective line. Vertical motions within the active convective region of the squall line system were determined using a new approach that utilized near-simultaneous observations by the Doppler radars on two aircraft with up to four Doppler radial velocity estimates at echo top. Echo-top vertical motion can then be derived directly, which obviates the traditional dual-Doppler assumption of no vertical velocity at the top boundary and results in a more accurate estimate of tropospheric vertical velocity through downward integration of horizontal divergence. Low-level Eight-level observations of temperature, wind speed, and dew point collected rearward of the squall line are used to estimate bulk fluxes of dry and moist static energy. The strong near-surface fluxes, due to the warm sea and high winds, combined with estimates of mesoscale advection, are used to estimate boundary layer recovery time; they indicate that the boundary layer could recover from the effects of the cold dome within about 3 h of first cold air injection if the observed near-surface winds were maintained. However, the injection and spreading of air from above leads to cooling at a fixed spot similar to 20 km rearward of the convective line (surface theta(c) minimum point), suggesting that the cold pool could be still intensifying at the time of observation. Recovery time at a point is probably similar to that measured in previous studies. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. RP NOAA, NSSL, MESOSCALE RES DIV, MAIL CODE N-C-MRD, 325 BROADWAY, BOULDER, CO 80303 USA. NR 54 TC 89 Z9 95 U1 1 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD AUG 1 PY 1997 VL 54 IS 15 BP 1961 EP 1985 DI 10.1175/1520-0469(1997)054<1961:SAEOTF>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN924 UT WOS:A1997XN92400003 ER PT J AU Sanogo, O Zachariah, MR AF Sanogo, O Zachariah, MR TI Kinetic studies of the reaction of tetraethoxysilane with oxygen atoms SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID GAS-PHASE AB The temperature dependent kinetics of the reaction of tetraethoxysilane (TEOS) with O atom have been determined by fast flow reactor molecular beam sampling. The rate of constant has the form k = 3.4 x 10 (-11) exp (-1304 K/T) cm(3) s(-1) over the temperature range 300 to 673 K and similar to that of H atom abstraction from carbon-bonded ethoxy groups. Gas-phase products of the chemistry have been analyzed which suggest that following formation of the primary radical, subsequent reactions lead to the formation of R3SiO and/or RnSi(OH)(4-n) (n < 4). These species are believed to undergo both four center elimination of ethylene and addition reactions to produce Si-O-Si ligands by dehydration. RP Sanogo, O (reprint author), NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 13 TC 23 Z9 23 U1 0 U2 6 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD AUG PY 1997 VL 144 IS 8 BP 2919 EP 2923 DI 10.1149/1.1837918 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XT453 UT WOS:A1997XT45300062 ER PT J AU Hayashi, Y Golder, DG AF Hayashi, Y Golder, DG TI United mechanisms for the generation of low- and high-frequency tropical waves .2. Theoretical interpretations SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article ID EVAPORATION-WIND FEEDBACK; CONVECTIVE ADJUSTMENT SCHEME; GENERALIZED STABILITY THEORY; MADDEN-JULIAN OSCILLATION; EQUATORIAL BETA-PLANE; ROSSBY-GRAVITY-WAVES; INTRASEASONAL OSCILLATIONS; CUMULUS PARAMETERIZATION; SCALE CIRCULATIONS; MODEL AB It is assumed that low-and high-frequency tropical waves are generated by the united mechanisms consisting of the evaporation-wind feedback (EWF), saturation-triggering (ST), and lateral-triggering mechanisms. Through the EWF mechanism, some waves become unstable owing to evaporation-wind feedback. Through the ST mechanism, other waves are triggered by the intermittent onset of moist convection, upon saturation, to neutralize any pre-existing conditionally unstable stratification. These mechanisms are theoretically interpreted by partitioning moist convective adjustment into two consecutive processes of diagnostic and prognostic adjustments. The two processes respectively restore and maintain convective equilibrium, and are crucial to the ST and EWF mechanisms. As a step to toward a unified theory, EWF instability is examined by the use of a theoretical Kelvin-wave model, which incorporates only the prognostic-adjustment process in the linearized perturbation equations, thereby excluding the ST mechanism. The solutions indicate that wave instability results from the EWF mechanism and not from the wave-CISK mechanism. For a plausible choice of adjustable parameters, one strongly unstable mode corresponds to the observed 40-50-day oscillation, while two weakly unstable modes correspond to the observed 25-30-day and 10-20-day oscillations. These results are compared with those from the numerical experiments conducted in Part I, using a nonlinear model incorporating the original moist convective adjustment scheme. It is then speculated that the 40-50- and 25-30-day modes can strongly grow through the linear and nonlinear EWF mechanisms respectively, while the 10-20-day mode can strongly amplify through the ST mechanism. RP Hayashi, Y (reprint author), PRINCETON UNIV, NOAA, GEOPHYS FLUID DYNAM LAB, POB 308, PRINCETON, NJ 08542 USA. NR 62 TC 5 Z9 5 U1 0 U2 0 PU METEOROLOGICAL SOC JAPAN PI TOKYO PA C/O JAPAN METEOROLOGICAL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO, 100-0004, JAPAN SN 0026-1165 EI 2186-9057 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD AUG PY 1997 VL 75 IS 4 BP 775 EP 797 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XY694 UT WOS:A1997XY69400002 ER PT J AU Sansonetti, CJ AF Sansonetti, CJ TI Precise measurements of hyperfine components in the spectrum of molecular iodine SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID FOURIER-TRANSFORM SPECTROSCOPY; LASER; LINES AB Absolute wave numbers with a typical uncertainty of 1 MHz (95% confidence) were measured for 102 hyperfine-structure components of I-127(2). The data cover the range 560 to 656 nm with no gaps larger than The spectra were observed by use of Doppler-free frequency-modulation spectroscopy with a tunable The laser was locked to selected iodine components, and its wave number was measured with a high-precision Fabry-Perot wavemeter. The accuracy of the results is confirmed by the good agreement of nine of the lines with previous results from other laboratories. These measurements provide a well-distributed set of precise reference lines for this spectral region. RP Sansonetti, CJ (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 17 TC 26 Z9 26 U1 3 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD AUG PY 1997 VL 14 IS 8 BP 1913 EP 1920 DI 10.1364/JOSAB.14.001913 PG 8 WC Optics SC Optics GA XP661 UT WOS:A1997XP66100001 ER PT J AU Terao, Y Takamoto, M Mattingly, GE AF Terao, Y Takamoto, M Mattingly, GE TI Preliminary intercomparison of anemometer calibration systems at very low speeds between the national standard laboratories in Japan and the USA SO JSME INTERNATIONAL JOURNAL SERIES B-FLUIDS AND THERMAL ENGINEERING LA English DT Article DE flow measurements; current meter; LDV; air speed measurement; tow carriage; wind tunnel; national standard; transfer standard; thermal anemometer; ultrasonic anemometer AB An international comparison of air speed standards has been conducted by Japan and the USA using anemometers. The national standard for low air speed measurement in Japan uses a tow carriage system with a laser-based speed determination system. In the USA, a specially designed low-speed wind tunnel equipped with a laser Doppler anemometer comprises the national standard. Two anemometers, one thermal and one ultrasonic, were selected as the transfer standards, and these were tested in the air speed range of 0.1 to 1 m/s. The results showed the two national standards to agree within the calibration uncertainties which were nominated to be between 1% and 9%. The results also indicated that the thermal anemometer used in this program had a transient characteristic and a sensitivity to the atmospheric pressure that required special analysis and data handling procedures. These characteristics and the procedures implemented are discussed and explanations are given that should improve future testing. C1 NIST,GAITHERSBURG,MD 20899. RP Terao, Y (reprint author), NATL RES LAB METROL,1-1-4 UMEZONO,TSUKUBA,IBARAKI 305,JAPAN. NR 12 TC 2 Z9 2 U1 1 U2 2 PU JAPAN SOC MECHANICAL ENGINEERS PI TOKYO PA SHINANOMACHI-RENGAKAN BLDG, SHINANOMACHI 35, SHINJUKU-KU, TOKYO 160, JAPAN SN 1340-8054 J9 JSME INT J B-FLUID T JI JSME Int. J. Ser. B-Fluids Therm. Eng. PD AUG PY 1997 VL 40 IS 3 BP 509 EP 515 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA YB575 UT WOS:A1997YB57500022 ER PT J AU Morgan, CA Cordell, JR Simenstad, CA AF Morgan, CA Cordell, JR Simenstad, CA TI Sink or swim? Copepod population maintenance in the Columbia River estuarine turbidity-maxima region SO MARINE BIOLOGY LA English DT Article ID EURYTEMORA-AFFINIS; VERTICAL MIGRATION; RETENTION; ZOOPLANKTON; RHYTHMS; LARVAE; FOOD AB Maintenance of estuarine zooplankton populations in large river-dominated estuaries with short residence times has been an intriguing subject of investigation. During three different hydrological seasons, autumn 1990, summer 1991, and spring 1992, we intensively sampled zooplankton populations in the estuarine turbidity maxima (ETM) region of the Columbia River estuary of Oregon and Washington, USA. One of the principal objectives was to investigate retention mechanisms of the predominant zooplankton species, the harpacticoid copepod Coullana canadensis and the epibenthic calanoid copepod Eurytemora affinis. In the ETM, C, canadensis densities mirrored those of turbidity gradients and were almost always greater at the river bed, while E. affinis densities were greater higher in the water column during the flood and lower in the water column during the ebb. Cross-correlation and time-series analyses determined that C. canadensis densities were highly positively correlated with turbidity and that most of the variability was explained by the lunisolar diurnal (K-1) and principal lunar (M-2) tidal components occurring once every 23.93 h and once every 12.42 h, respectively. This indicates that C. canadensis populations are most probably maintained in the estuary through the same near-bottom circulation features that trap and concentrate particles in the ETM. In contrast, densities of the more motile species E. affinis were highly correlated with negative velocities, or ebb tide, and most of the variability in population densities could be explained by the principal lunar tidal component; therefore, we hypothesize that this species is probably vertically migrating on a tidal cycle into different flow layers to avoid population losses out of the estuary. C1 UNIV WASHINGTON,FISHERIES RES INST,SEATTLE,WA 98195. RP Morgan, CA (reprint author), CZES,NMFS,HATFIELD MARINE SCI CTR,2030 S MARINE SCI DR,NEWPORT,OR 97365, USA. NR 40 TC 72 Z9 77 U1 1 U2 18 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD AUG PY 1997 VL 129 IS 2 BP 309 EP 317 DI 10.1007/s002270050171 PG 9 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA XW285 UT WOS:A1997XW28500011 ER PT J AU Phillips, WD AF Phillips, WD TI Quantum motion of atoms confined in an optical lattice SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article; Proceedings Paper CT 6th NEC Symposium on Quantum Optical Phenomena in Spatially Confined Materials - Fundamental Approaches to New Material Phases CY OCT 13-17, 1996 CL KARUIZAWA, JAPAN SP NEC Corp DE atomic fluorescence spectrum; Bragg scattering; laser cooling of atoms; optical lattice ID RESONANCE RADIATION PRESSURE; COLD CESIUM ATOMS; INTENSITY CORRELATIONS; RAYLEIGH SPECTROSCOPY; QUANTIZED MOTION; STIMULATED RAMAN; DOPPLER LIMIT; MOLASSES; FLUORESCENCE; CRYSTAL AB An optical lattice is a periodic array of potential wells for atoms, formed by the interference of several laser beams. These lattices have interesting similarities to and differences from solid crystal lattices. We study the motion of atoms trapped and laser-cooled in such lattices by measuring the atoms' temperature when released, by examining the spectrum of light emitted by the atoms, and by Bragg scattering of light from the lattice. We find results that are in good quantitative agreement with detailed quantum mechanical calculations. (C) 1997 Elsevier Science S.A. RP NATL INST STAND & TECHNOL, ATOM PHYS DIV, PHY A167, GAITHERSBURG, MD 20899 USA. NR 52 TC 3 Z9 3 U1 3 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD AUG 1 PY 1997 VL 48 IS 1-2 BP 13 EP 18 DI 10.1016/S0921-5107(97)00074-3 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA XY086 UT WOS:A1997XY08600004 ER PT J AU Coletti, JG Pearson, DW DeWerd, LA OBrien, CM Lamperti, PJ AF Coletti, JG Pearson, DW DeWerd, LA OBrien, CM Lamperti, PJ TI Comparison of exposure standards in the mammography x-ray region SO MEDICAL PHYSICS LA English DT Article DE free-air ionization chamber; calibration; mammography; dosimetry AB Direct comparisons of the National Institute of Standards and Technology's (NIST) Ritz 20 kV to 100 kV standard free-air ionization chamber and a portable variable-length free-air ionization chamber designed by the University of Wisconsin - Madison Accredited Dosimetry Calibration Laboratory (UW-ADCL) were made on NISTs low-energy tungsten x-ray range. As a result of this direct comparison, NIST has established a UW-ADCL designed chamber, the Attix chamber, as the national standard chamber for the mammography energy x-ray range. The Ritz standard chamber and the Attix standard chamber have been extensively compared using the new molybdenum and rhodium beam qualities. The results indicate that exposure measurements in the mammography energy x-ray region with the two free-air chambers can be made with a discrepancy of less than 0.35%. (C) 1997 American Association of Physicists in Medicine. C1 UNIV WISCONSIN,DEPT MED PHYS,MADISON,WI 53706. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. FU NCI NIH HHS [1 R01 CA60575-01A1] NR 8 TC 10 Z9 10 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0094-2405 J9 MED PHYS JI Med. Phys. PD AUG PY 1997 VL 24 IS 8 BP 1263 EP 1267 DI 10.1118/1.598148 PG 5 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA XR369 UT WOS:A1997XR36900009 PM 9284250 ER PT J AU Smirnova, TG Brown, JM Benjamin, SG AF Smirnova, TG Brown, JM Benjamin, SG TI Performance of different soil model configurations in simulating ground surface temperature and surface fluxes SO MONTHLY WEATHER REVIEW LA English DT Article ID BOUNDARY-LAYER; NUMERICAL-MODEL; WEATHER PREDICTION; MOISTURE; PARAMETERIZATION; CIRCULATION; SENSITIVITY; ATMOSPHERE; HYDROLOGY AB This study compares three modifications to the one-dimensional planetary boundary layer scheme that is implemented in the sigma-theta hybrid-b version of the Mesoscale Analysis and Prediction System (MAPS) and the Rapid Update Cycle (RUC). All three modifications are based on the incorporation of a simple soil model into the basic version to more accurately calculate the moisture and heat fluxes across the ground surface. The presented schemes are of increasing sophistication: the first model combines the soil model with heat and moisture budget equations for the ground surface and uses an explicit numerical scheme to compute the surface fluxes: the second model uses a more energy-conservative implicit solution for the latent and sensible surface fluxes and heat and moisture soil fluxes: the third model further incorporates a simple parameterization of the evapotranspiration process. The comparison includes the effect of different schemes on diurnal changes of surface temperature and soil heat Aux. The schemes are tested for two case studies; a dry case from the O'Neill, Nebraska. Great Plains Turbulence Field Program and a moist case from the First ISLSCP (international Satellite Land Surface Climatology Project) Field Experiment. Tests are performed to evaluate sensitivity to soil parameters related to thermal diffusivity and to vertical resolution of the soil scheme. Overall, the comparison supports the idea that implementation of a multilevel soil model is competitive with and can even improve the ground surface temperature forecast over that produced by the present MAPS implementation of the force restore method. The case study demonstrates that incorporation of a primitive evapotranspiration model can give positive results. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Smirnova, TG (reprint author), NOAA,ENVIRONM RES LAB,FSL,R E FS1,325 BROADWAY,BOULDER,CO 80303, USA. RI Benjamin, Stan/C-5818-2015; Smirnova, Tatiana/D-3350-2015; Brown, John/D-3361-2015 OI Benjamin, Stan/0000-0002-5751-8236; NR 52 TC 106 Z9 114 U1 1 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD AUG PY 1997 VL 125 IS 8 BP 1870 EP 1884 DI 10.1175/1520-0493(1997)125<1870:PODSMC>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XP303 UT WOS:A1997XP30300010 ER PT J AU Zhao, QY Carr, FH AF Zhao, QY Carr, FH TI A prognostic cloud scheme for operational NWP models SO MONTHLY WEATHER REVIEW LA English DT Article ID CONVECTIVE ADJUSTMENT SCHEME; STEP-MOUNTAIN COORDINATE; WEATHER PREDICTION MODEL; MID-LATITUDE CYCLONES; WATER-CONTENT; PARAMETERIZATION; MESOSCALE; CONDENSATION AB An explicit cloud prediction model has been developed and incorporated into the Era Model at the National Centers for Environmental Prediction. In this scheme, only one predictive variable, cloud mixing ratio, is added to the model's prognostic equations to represent both cloud liquid water and cloud ice. Precipitation is diagnostically calculated from cloud mixing ratio. Extensive tests have been performed. The statistical results show a significant improvement in the model precipitation forecasts. Diagnostic studies suggest that the inclusion of cloud ice is important in transferring water vapor to precipitation and in the enhancement of latent hear release; the latter subsequently affects the vertical motion field significantly. C1 GEN SCI CORP,NATL CTR ENVIRONM PREDICT,WASHINGTON,DC. UNIV OKLAHOMA,SCH METEOROL,NORMAN,OK 73019. NR 28 TC 142 Z9 148 U1 1 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD AUG PY 1997 VL 125 IS 8 BP 1931 EP 1953 DI 10.1175/1520-0493(1997)125<1931:APCSFO>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XP303 UT WOS:A1997XP30300014 ER PT J AU NataliSora, I Huang, Q Santoro, A Cava, RJ Krajewski, JJ Peck, WF AF NataliSora, I Huang, Q Santoro, A Cava, RJ Krajewski, JJ Peck, WF TI Crystal structure of Y(0.95)Ca(0.05)CuO(2.54): a new oxygen-deficient perovskite chemically and structurally related to the ''123'' superconductor SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA D-CONDENSED MATTER ATOMIC MOLECULAR AND CHEMICAL PHYSICS FLUIDS PLASMAS BIOPHYSICS LA English DT Article; Proceedings Paper CT VIII Congress of SATT CY OCT 01-04, 1996 CL COMO, ITALY SP SATT ID DELAFOSSITES AB The crystal structure of Y0.95Ca0.05CuO2.54(1) has been determined by neutron powder diffraction at room temperature. The compound crystallizes with the symmetry of the hexagonal space group P6(3)/m and lattice parameters alpha = 6.1991(2), c = 11.2059(3) Angstrom. The configuration of the atoms in the unit cell may be alternatively described as an AgFeO2-type structure with extra oxygen atoms in the copper plane, or as an oxygen-deficient perovskite of general formula ABO(3-x) (x = 0.46) chemically and structually related to the ''123'' superconductor oxide. In the unit cell the sequence of layers is ...[(Y3O6)(Cu2.43O1.62 + Cu-0.57)(Y3O6)(Cu2.43O1.62 + Cu-0.57)]... . The yttrium and calcium atoms are mixed over three symmetrically independent sites. The coordination number of Y/Ca atoms is seven. The defective layer can be derived from a defective perovskite layer BO2 in which rows of oxygen atoms are interleaved with double rows of oxygen vacancies, giving an oxygen stoichiometry of O-2.67. The shifts of the oxygen atoms from their original perovskite positions and the hexagonal distortion of the lattice result in tetrahedral coordination around each Cu atom. The additional oxygen vacancies in the copper layers necessary to reduce the oxygen stoichiometry to O-2.54 are assumed to be randomly distributed. C1 UNIV BRESCIA, DIPARTIMENTO CHIM & FIS MAT, I-25123 BRESCIA, ITALY. UNIV MARYLAND, COLLEGE PK, MD 20742 USA. AT&T BELL LABS, MURRAY HILL, NJ 07974 USA. RP NataliSora, I (reprint author), NIST, DIV REACTOR RADIAT, GAITHERSBURG, MD 20899 USA. RI Natali Sora, Isabella/C-8357-2011 NR 8 TC 0 Z9 0 U1 1 U2 3 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 0392-6737 J9 NUOVO CIMENTO D JI Nuovo Cimento Soc. Ital. Fis. D-Condens. Matter At. Mol. Chem. Phys. Fluids Plasmas Biophys. PD AUG-SEP PY 1997 VL 19 IS 8-9 BP 1093 EP 1101 PG 9 WC Physics, Multidisciplinary SC Physics GA YE563 UT WOS:A1997YE56300014 ER PT J AU Paek, EG Choe, JY Oh, TK Hong, JH Chang, TY AF Paek, EG Choe, JY Oh, TK Hong, JH Chang, TY TI Nonmechanical image rotation with an acousto-optic dove prism SO OPTICS LETTERS LA English DT Article AB We report what we believe to be the first method for nonmechanical and programmable image rotation. The method uses a pair of crossed acousto-optic beam deflectors and a polygon mirror to emulate the mechanical dove prism. It is capable of fast (of the order of microseconds) image rotation to an arbitrary angle in a programmable manner. An experimental result that proves the concept is provided. C1 USN,CTR SURFACE WARFARE,DAHLGREN,VA 22448. ROCKWELL INT SCI CTR,THOUSAND OAKS,CA 91360. RP Paek, EG (reprint author), NIST,INFORMAT TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 9 TC 15 Z9 16 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD AUG 1 PY 1997 VL 22 IS 15 BP 1195 EP 1197 DI 10.1364/OL.22.001195 PG 3 WC Optics SC Optics GA XM918 UT WOS:A1997XM91800023 PM 18185793 ER PT J AU Keimer, B Fong, HF Lee, SH Milius, DL Aksay, IA AF Keimer, B Fong, HF Lee, SH Milius, DL Aksay, IA TI Doping dependence of the magnetic resonance peak in YBa2Cu3O6+x SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID SUPERCONDUCTING ORDER-PARAMETER; NEUTRON-SCATTERING; CUPRATE SUPERCONDUCTORS; FLUCTUATIONS; EXCITATIONS; BILAYER; GAP AB We report inelastic neutron scattering experiments on the doping dependence of the energy and spectral weight of the sharp magnetic resonance peak in YBa2Cu3O6+x. These measurements also shed light on the relationship between the magnetic excitations in the normal and superconducting states. C1 NIST,REACTOR DIV,GAITHERSBURG,MD 20899. PRINCETON UNIV,DEPT CHEM ENGN,PRINCETON,NJ 08544. RP Keimer, B (reprint author), PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544, USA. RI Aksay, Ilhan/B-9281-2008 NR 25 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 232 EP 235 DI 10.1016/S0921-4534(97)00222-0 PN 1 PG 4 WC Physics, Applied SC Physics GA XZ904 UT WOS:A1997XZ90400064 ER PT J AU Lei, M Migliori, A Ledbetter, H AF Lei, M Migliori, A Ledbetter, H TI Acoustic evidence against BCS behavior in monocrystal YBa2Cu3O7 SO PHYSICA C LA English DT Article; Proceedings Paper CT International Conference on Materials and Mechanisms of Superconductivity - High Temperature Superconductors V CY FEB 28-MAR 04, 1997 CL BEIJING, PEOPLES R CHINA SP IChemE ID ANELASTIC RELAXATION AB Using a detwinned YBa2Cu3O7 monocrystal and acoustic-resonance spectroscopy, we measured internal friction Q(-1) = Delta f/f(r) through the 91-K superconducting-transition temperature. We show measurements for the first ten macroscopic resonance frequencies f(r). None of the modes show classic BCS-model behavior based on simple-pairing, isotropic-s-electron, weak-coupling assumptions. Beside being non-BCS-like, essentially every mode behaves differently, suggesting a strongly anisotropic energy gap Delta(k), and practically ruling out any simple Fermi-surface gap function, especially s-wave. Some modes actually show increasing Q(-1) upon cooling below T-c, suggesting either strong Fermi-surface changes or lattice-relaxation mechanisms. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. RP Lei, M (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 8 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD AUG PY 1997 VL 282 BP 1077 EP 1078 DI 10.1016/S0921-4534(97)00643-6 PN 2 PG 2 WC Physics, Applied SC Physics GA XZ905 UT WOS:A1997XZ90500320 ER PT J AU Bohn, JL Julienne, PS AF Bohn, JL Julienne, PS TI Prospects for influencing scattering lengths with far-off-resonant light SO PHYSICAL REVIEW A LA English DT Article ID LONG-RANGE STATES; PHOTOASSOCIATION SPECTROSCOPY; GROUND-STATE; ATOMS; SPECTRA; LI-7(2) AB We explore a recent proposal [Fedichev et al., Phys. Rev. Lett. 77, 2913 (1996)] for altering the mean interaction strength between ultracold atoms using an appropriately detuned laser. Although care must be taken to minimize laser-driven loss processes, we find large ranges of intensities and detunings where useful changes might be affected. Accordingly, we present simple formulas for the effects of laser light that should prove useful in designing specific experiments. We demonstrate the validity of these formulas by comparison with exact close-coupling models. In particular, we find that useful changes of the mean-field interaction require sufficiently high laser intensities that the rate of laser-induced stimulated emission exceeds the natural spontaneous emission rate. C1 NATL INST STAND & TECHNOL,QUANTUM PHYS DIV,BOULDER,CO 80309. NIST,ATOM PHYS DIV,GAITHERSBURG,MD 20899. RP Bohn, JL (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. RI Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 36 TC 128 Z9 128 U1 2 U2 10 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 AUG PY 1997 VL 56 IS 2 BP 1486 EP 1491 DI 10.1103/PhysRevA.56.1486 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XQ618 UT WOS:A1997XQ61800058 ER PT J AU Wang, P Gallagher, A Cooper, J AF Wang, P Gallagher, A Cooper, J TI Selective reflection by Rb SO PHYSICAL REVIEW A LA English DT Article ID SODIUM VAPOR; SPECTROSCOPY; INTERFACE; RESONANCE AB Perpendicular reflection of low-power, near-resonant radiation at a sapphire-Ph-vapor interface (selective reflection) has been measured for Rb densities of 3 x 10(14)-3 x 10(17)/cm(3). At the lowest density the eight hyperfine components are essentially isolated, and at the highest pressure they are highly blended. The data have been fitted to a coherent superposition of the reflected field amplitudes of the eight components, including the well-known starting transient and wall interaction. At low to moderate densities this yields a good lit to the data, and a result for the Rb-Rb collisional shift. At the higher densities the rapid attenuation of the incident field has a major effect on the reflection spectrum, and an approximation to this is included in the calculation, assuming exponential attenuation at the equilibrium-vapor rate. This provides improved fits to the data and allows the apparent Lorentz-Lorenz plus collisional shift to be evaluated. However, the data do not fully fit this calculation, and a complete self-consistent-field calculation appears necessary to fully understand the high-pressure results. C1 UNIV COLORADO, BOULDER, CO 80309 USA. RP Wang, P (reprint author), NATL INST STAND & TECHNOL, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. NR 23 TC 28 Z9 28 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 1997 VL 56 IS 2 BP 1598 EP 1606 DI 10.1103/PhysRevA.56.1598 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XQ618 UT WOS:A1997XQ61800073 ER PT J AU Armen, GB Southworth, SH Levin, JC Arp, U LeBrun, T MacDonald, MA AF Armen, GB Southworth, SH Levin, JC Arp, U LeBrun, T MacDonald, MA TI Xenon spectator and diagram L-3-M4,5M4,5 Auger intensities near the L-3 threshold SO PHYSICAL REVIEW A LA English DT Article ID POST-COLLISION INTERACTION; SYNCHROTRON RADIATION; POSTCOLLISION INTERACTION; SPECTRA; STATES AB Calculations based on the theory of radiationless resonant Raman scattering are employed in the interpretation of new Xe L-3-M4,5M4,5 Auger spectra recorded using synchrotron radiation tuned to energies across the L-3 edge. Fits of theoretical line shapes to the spectra are employed in separating intensities due to nd spectator (resonant) and diagram Auger processes. Near-threshold Anger intensity, previously attributed to diagram decay, is found to be due to the large-n spectator lines that result from postcollision-interaction-induced ''recapture'' of threshold photoelectrons to nd orbitals. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. NIST,GAITHERSBURG,MD 20899. SERC,DARESBURY LAB,ENGN & PHYS SCI RES COUNCIL,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. RP Armen, GB (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37996, USA. RI Arp, Uwe/C-2854-2009; OI Arp, Uwe/0000-0002-6468-9455 NR 18 TC 22 Z9 22 U1 0 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 AUG PY 1997 VL 56 IS 2 BP R1079 EP R1082 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XQ618 UT WOS:A1997XQ61800005 ER PT J AU Gebbie, KB Rumble, JR AF Gebbie, KB Rumble, JR TI Jean Weil Gallagher - Obituary SO PHYSICS TODAY LA English DT Item About an Individual RP Gebbie, KB (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD AUG PY 1997 VL 50 IS 8 BP 78 EP 78 DI 10.1063/1.881865 PN 1 PG 1 WC Physics, Multidisciplinary SC Physics GA XP137 UT WOS:A1997XP13700022 ER PT J AU Phelan, FR AF Phelan, FR TI Simulation of the injection process in resin transfer molding SO POLYMER COMPOSITES LA English DT Article ID FLOW AB A simulation based on Darcy's law for modeling mold filling in resin transfer molding has been developed. The simulation uses a new Flow Analysis Network (FAN) technique to predict and track the movement of the free-surface, and a finite element method to solve the governing equation set for each successive flow front location. A variety of element types have been incorporated into the simulation, enabling modeling of flow for a variety of conditions of industrial interest including runner distribution systems, ''2.5-D'' shell geometries, and fully 3-D flows. The FAN technique developed here has two main benefits: it enables conservation of mass, even for highly distorted element shapes, and also, allows elements of different dimension to be simultaneously used in a single simulation. At present, the simulation predicts flow front position as a function of time, and the pressure distribution during the filling process for a number of inlet gating conditions. A number of examples are presented and discussed to highlight the simulation's capabilities, including the filling of a complex automotive part. RP Phelan, FR (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 21 TC 64 Z9 64 U1 1 U2 7 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0272-8397 J9 POLYM COMPOSITE JI Polym. Compos. PD AUG PY 1997 VL 18 IS 4 BP 460 EP 476 DI 10.1002/pc.10298 PG 17 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA XR286 UT WOS:A1997XR28600004 ER PT J AU Neff, RA Woerdeman, DL Parnas, RS AF Neff, RA Woerdeman, DL Parnas, RS TI Use of a charged coupled device (CCD) camera for evanescent wave optical fiber cure monitoring of liquid composite molding resins SO POLYMER COMPOSITES LA English DT Article ID EPOXY AB An optical fiber evanescent wave fluorescence cure sensor described in a previous paper (1) has been interfaced with a fast detector and computer software to provide real-time monitoring of fast-reacting systems. Advantages to the new system include a reduction in data acquisition time (to 200 ms from 3 min), improved time resolution (to 5 sec from 10 min), and improved signal quality. Isothermal cure monitoring measurements were conducted in both distal and evanescent wave sampling modes for an epoxy-amine system. Following a second order background correction, the results for the two sampling modes were identical. Thus the evanescent wave measurement was unable to detect differences between the chemistry in the bulk and at the fiber-resin interface (if there were any differences to observe). The sensor system was also demonstrated for a fast curing (<3 min gel time) polyurethane-isocyanurate system designed for high volume (short cycle time) automotive applications. The system is currently being modified for implementation in a ''real world'' manufacturing environment. C1 COLL FRANCE,PHYS MAT CONDENSEE LAB,F-75231 PARIS 05,FRANCE. RP Neff, RA (reprint author), NIST,DIV POLYMERS,GAITHERSBURG,MD 20899, USA. NR 20 TC 13 Z9 13 U1 0 U2 4 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0272-8397 J9 POLYM COMPOSITE JI Polym. Compos. PD AUG PY 1997 VL 18 IS 4 BP 518 EP 525 DI 10.1002/pc.10304 PG 8 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA XR286 UT WOS:A1997XR28600010 ER PT J AU Schutte, CJH Bertie, JE Bunker, PR Hougen, JT Mills, IM Watson, JKG Winnewisser, BP AF Schutte, CJH Bertie, JE Bunker, PR Hougen, JT Mills, IM Watson, JKG Winnewisser, BP TI Notations and conventions in molecular spectroscopy .1. General spectroscopic notation SO PURE AND APPLIED CHEMISTRY LA English DT Article AB The field of Molecular Spectroscopy was surveyed in order to determine a set of conventions and symbols which are in common use in the spectroscopic literature. This document, which is Part 1 in a series, establishes the notations and conventions used for general spectroscopic notations and deals with quantum mechanics, quantum numbers (vibrational states, angular momentum and energy levels), spectroscopic transitions, and miscellaneous notations (e.g. spectroscopic terms). Further parts will follow, dealing inter alia with symmetry, notation, permutation and permutation-inversion symmetry notation, vibration-rotation spectroscopy and electronic spectroscopic. C1 UNIV ALBERTA,DEPT CHEM,EDMONTON,AB T6G 2G2,CANADA. NATL RES COUNCIL CANADA,STEACIE INST MOL SCI,OTTAWA,ON K1A 0R6,CANADA. NIST,DIV MOL PHYS,GAITHERSBURG,MD 20899. UNIV READING,DEPT CHEM,CATALYSIS RES GRP,READING RG6 2AD,BERKS,ENGLAND. UNIV GIESSEN,INST PHYS CHEM,D-6300 GIESSEN,GERMANY. RP Schutte, CJH (reprint author), UNIV S AFRICA,POB 392,ZA-0001 PRETORIA,SOUTH AFRICA. NR 4 TC 3 Z9 3 U1 2 U2 7 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD AUG PY 1997 VL 69 IS 8 BP 1633 EP 1639 DI 10.1351/pac199769081633 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA XW531 UT WOS:A1997XW53100002 ER PT J AU Schutte, CJH Bertie, JE Bunker, PR Hougen, JT Mills, IM Watson, JKG Winnewisser, BP AF Schutte, CJH Bertie, JE Bunker, PR Hougen, JT Mills, IM Watson, JKG Winnewisser, BP TI Notations and conventions in molecular spectroscopy .2. Symmetry notation SO PURE AND APPLIED CHEMISTRY LA English DT Article AB The field of Molecular Spectroscopy was surveyed in order to determine a set of conventions and symbols which are in common use in the spectroscopic literature. This document, which is Part 2 in a series, establishes the notations and conventions used for the description of symmetry, in rigid molecules, using the Schoenflies notation. It deals firstly with the symmetry operators of the molecular point groups (also drawing attention to the difference between symmetry operators and elements). The conventions and notations of the molecular point groups are then established, followed by those of the representations of these groups as used in molecular spectroscopy. Further parts will follow, dealing inter alia with permutation and permutation-inversion symmetry notation, vibration-rotation spectroscopy and electronic spectroscopy. C1 UNIV ALBERTA,DEPT CHEM,EDMONTON,AB T6G 2G2,CANADA. NATL RES COUNCIL CANADA,STEACIE INST MOL SCI,OTTAWA,ON K1A 0R6,CANADA. NIST,DIV MOL PHYS,GAITHERSBURG,MD 20899. UNIV READING,DEPT CHEM,READING RG6 2AD,BERKS,ENGLAND. UNIV GIESSEN,INST PHYS CHEM,D-6300 GIESSEN,GERMANY. RP Schutte, CJH (reprint author), UNIV S AFRICA,POB 392,ZA-0001 PRETORIA,SOUTH AFRICA. NR 9 TC 11 Z9 11 U1 2 U2 7 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD AUG PY 1997 VL 69 IS 8 BP 1641 EP 1649 DI 10.1351/pac199769081641 PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA XW531 UT WOS:A1997XW53100003 ER PT J AU Bunker, PR Schutte, CJH Hougen, JT Mills, IM Watson, JKG Winnewisser, BP AF Bunker, PR Schutte, CJH Hougen, JT Mills, IM Watson, JKG Winnewisser, BP TI Notations and conventions in molecular spectroscopy .3. Permutation and permutation-inversion symmetry notation SO PURE AND APPLIED CHEMISTRY LA English DT Article AB The field of Molecular Spectroscopy was surveyed in order to determine a set of conventions and symbols which are in common use in the spectroscopic literature. This document, which is Part 3 in a series, deals with symmetry notation referring to groups that involve nuclear permutations and the inversion operation. Further parts will follow, dealing inter alia with vibration-rotation spectroscopy and electronic spectroscopy. C1 UNIV S AFRICA,ZA-0001 PRETORIA,SOUTH AFRICA. NIST,DIV MOL PHYS,GAITHERSBURG,MD 20899. UNIV READING,DEPT CHEM,READING RG6 2AD,BERKS,ENGLAND. UNIV GIESSEN,INST PHYS CHEM,D-6300 GIESSEN,GERMANY. RP Bunker, PR (reprint author), NATL RES COUNCIL CANADA,STEACIE INST MOL SCI,100 SUSSEX DR,OTTAWA,ON K1A 0R6,CANADA. NR 4 TC 4 Z9 4 U1 2 U2 4 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD AUG PY 1997 VL 69 IS 8 BP 1651 EP 1657 DI 10.1351/pac199769081651 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA XW531 UT WOS:A1997XW53100004 ER PT J AU Pipino, ACR Hudgens, JW Huie, RE AF Pipino, ACR Hudgens, JW Huie, RE TI Evanescent wave cavity ring-down spectroscopy with a total-internal-reflection minicavity SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID LASER-ABSORPTION SPECTROSCOPY; THEORETICAL-ANALYSIS; KINETICS; RESONATOR; PROPAGATION; SCATTERING; STABILITY; SURFACES; SYSTEMS AB A miniature-cavity realization of the cavity ring-down concept, which permits extension of the technique to spectroscopy of surfaces, thin films, liquids, and, potentially, solids, is explored using a wave-optics model. The novel spectrometer design incorporates a monolithic, total-internal-reflection-ring cavity of regular polygonal geometry with at least one convex facet to induce stability. Evanescent waves generated by total-internal reflection probe absorption by matter in the vicinity of the cavity. Optical radiation enters or exits the resonator by photon tunneling, which permits precise control of input and output coupling. The broadband nature of total-internal reflection circumvents the narrow bandwidth restriction imposed by dielectric mirrors in conventional gas-phase cavity ring-down spectroscopy. Following a general discussion of design criteria, calculations are presented for square and octagonal cavity geometries that quantify intrinsic losses and reveal an optimal cavity size for each geometry. Calculated absorption spectra for the NO3 radical from 450 to 750 nm in a nitric acid solution an presented to demonstrate bandwidth and sensitivity. RP Pipino, ACR (reprint author), NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899, USA. RI Huie, Robert/A-5645-2010 NR 69 TC 84 Z9 84 U1 1 U2 17 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD AUG PY 1997 VL 68 IS 8 BP 2978 EP 2989 DI 10.1063/1.1148230 PG 12 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA XR753 UT WOS:A1997XR75300005 ER PT J AU Newell, DB Richman, SJ Nelson, PG Stebbins, RT Bender, PL Faller, JE Mason, J AF Newell, DB Richman, SJ Nelson, PG Stebbins, RT Bender, PL Faller, JE Mason, J TI An ultra-low-noise, low-frequency, six degrees of freedom active vibration isolator SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID SEISMIC NOISE AB To extend the operating frequency band of earth-based interferometric gravitational wave (GW) detectors down to 1 Hz, an unconventional system is required that provides approximately a factor of one million vibration isolation for the horizontal and more for the vertical, starting at 1 Hz. To this end, a three-stage ultra-low-noise, high-performance active and passive isolation system is being designed and constructed in order to demonstrate that a high degree of reduction can be achieved for vibrations at the support points of a GW detector's final pendulum system. The first stage of this system has been fully characterized and is the main subject of this article. It is an equilateral triangular platform, 1.1 m on a side, with a total mass of 460 kg, including the vacuum system that will contain the other two stages. Active isolation is achieved by six servocontrol loops, using signals from low-frequency displacement sensors to feed back to noncontacting force transducers. The first stage has been actively isolated from vibrations in all six degrees of freedom by at least a factor of 100 at I Hz and above. The system noise limitations at 2 Hz and above are roughly 2x10(-11) and 5x10(-11) m/root Hz for vertical and horizontal translations, respectively. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. UNIV COLORADO,BOULDER,CO 80309. METROPOLITAN STATE COLL,DENVER,CO 80217. RI Stebbins, Robin/G-5009-2013 NR 14 TC 27 Z9 29 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD AUG PY 1997 VL 68 IS 8 BP 3211 EP 3219 DI 10.1063/1.1148269 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA XR753 UT WOS:A1997XR75300048 ER PT J AU Piotrowicz, SR AF Piotrowicz, SR TI TOGA observing system & GOOS SO SEA TECHNOLOGY LA English DT Article RP Piotrowicz, SR (reprint author), NOAA,ROCKVILLE,MD 20852, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD AUG PY 1997 VL 38 IS 8 BP 39 EP 44 PG 6 WC Engineering, Ocean SC Engineering GA XT271 UT WOS:A1997XT27100006 ER PT J AU Filliben, JJ Li, KC AF Filliben, JJ Li, KC TI A systematic approach to the analysis of complex interaction patterns in two-level factorial designs SO TECHNOMETRICS LA English DT Article DE data visualization; dimension reduction; linear-domain analysis; partition tree; principal Hessian direction; residual analysis; splitting ID DIMENSION REDUCTION; TESTABILITY AB Analysis of data from two-level full factorial designs often ends up with a final prediction equation that gives only the significant main-effect and interaction terms. When the number of interactions is small, simple and useful interpretation of the equation can then be drawn immediately. This article addresses a different situation in which the number of significant interactions may be large so that additional efforts are needed to sort but the pattern and the relationship between them. In particular, we bring out a class of models in which most interactions can be attributed to just one or two (or very few) factors, and conditional on these factors, the models become essentially linear. We offer a strategy for uncovering this structure by linear domain splitting, whereby a complicated global model is replaced by a series of local domain-specific linear models. We present a recommended methodology (PHD-principal Hessian direction) for systematically proceeding from the global equation to local split-domain analyses. The net result is that guided tree-structured paths are offered for visiting the source-of-interaction factors in sequence, which appropriately reflects their relative importance and mutual relationship. The final stage modeling is simpler (linear). The quality of the fit can be assessed separately in each region, and the analyst comes away with greater insight as to the sensitivity and robustness of the various factor effects over various regions. Applications in digital electronics testing are illustrated by analyzing a dataset collected for studying the conversion error of a digital-to-analog converter. C1 UNIV CALIF LOS ANGELES,DEPT MATH,LOS ANGELES,CA 90024. RP Filliben, JJ (reprint author), NATL INST STAND & TECHNOL,STAT ENGN DIV,GAITHERSBURG,MD 20899, USA. NR 14 TC 10 Z9 10 U1 1 U2 1 PU AMER STATISTICAL ASSOC PI ALEXANDRIA PA 1429 DUKE ST, ALEXANDRIA, VA 22314 SN 0040-1706 J9 TECHNOMETRICS JI Technometrics PD AUG PY 1997 VL 39 IS 3 BP 286 EP 297 DI 10.2307/1271133 PG 12 WC Statistics & Probability SC Mathematics GA XM272 UT WOS:A1997XM27200005 ER PT J AU Saugier, B Granier, A Pontailler, JY Dufrene, E Baldocchi, DD AF Saugier, B Granier, A Pontailler, JY Dufrene, E Baldocchi, DD TI Transpiration of a boreal pine forest measured by branch bag, sap flow and micrometeorological methods SO TREE PHYSIOLOGY LA English DT Article DE canopy transpiration; eddy covariance method; jack pine; Pinus banksiana; transpiration rate; water loss; water vapor flux ID STOMATAL CONDUCTANCE; MARITIME PINE; FLUX; CO2; MODEL; STAND AB Three independent methods were used to evaluate transpiration of a boreal forest: the branch bag, sap flow and eddy covariance methods. The branch bag method encloses several thousand needles and gives a continuous record of branch transpiration, The sap flow method provides a continuous record of sap velocity and an estimate of tree transpiration. The eddy covariance method typically measures evaporation rates between a forest and the atmosphere. We deployed an extra eddy covariance system below the forest to estimate canopy transpiration by difference, The three systems detected small water vapor fluxes despite a plentiful supply of energy to drive evaporation. We also observed that transpiration rates were low even when the soil was well supplied with water. Low rates of transpiration were attributed to the canopy's low leaf area index and the marked reduction in stomatal conductance as vapor pressure deficits increased. Water vapor fluxes, derived from the sap flow method, lagged behind those derived by the branch bag method by 1 to 2 h. The sap flow method also suffered from sampling errors caused by the non-uniformity of flow across the sapwood and the spatial variability of sapwood cross section throughout the forest. Despite technical difficulties associated with hourly measurements, daily totals of transpiration agreed well with values derived from micrometeorological systems. C1 INRA,UNITE ECOL FORESTIERE,F-54280 CHAMPENOUX,FRANCE. NOAA,ATMOSPHER TURBULENCE & DIFFUS DIV,ARL,OAK RIDGE,TN 37831. RP Saugier, B (reprint author), UNIV PARIS 11,CNRS,URA 2154,BATIMENT 362,F-91405 ORSAY,FRANCE. RI Baldocchi, Dennis/A-1625-2009 OI Baldocchi, Dennis/0000-0003-3496-4919 NR 24 TC 96 Z9 112 U1 1 U2 22 PU HERON PUBLISHING PI VICTORIA PA 202, 3994 SHELBOURNE ST, VICTORIA BC V8N 3E2, CANADA SN 0829-318X J9 TREE PHYSIOL JI Tree Physiol. PD AUG-SEP PY 1997 VL 17 IS 8-9 BP 511 EP 519 PG 9 WC Forestry SC Forestry GA YK381 UT WOS:A1997YK38100003 ER PT J AU Chinchilla, D Eisenstein, E AF Chinchilla, D Eisenstein, E TI Genetic and biophysical approaches reveal control features of allosteric threonine deaminase SO FASEB JOURNAL LA English DT Meeting Abstract C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 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 0892-6638 J9 FASEB J JI Faseb J. PD JUL 31 PY 1997 VL 11 IS 9 SU S MA 978 BP A1025 EP A1025 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ZK302 UT WOS:000073305601463 ER PT J AU Holden, MJ Mayhew, M Bunk, D Roitberg, A Vilker, VL AF Holden, MJ Mayhew, M Bunk, D Roitberg, A Vilker, VL TI Probing the interactions of putidaredoxin with redox partners in camphor P450 5-monooxygenase SO FASEB JOURNAL LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 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 0892-6638 J9 FASEB J JI Faseb J. PD JUL 31 PY 1997 VL 11 IS 9 SU S MA P108 BP A790 EP A790 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ZK302 UT WOS:000073305600109 ER PT J AU Zondlo, J Eisenstein, E AF Zondlo, J Eisenstein, E TI The effect of GroES instability on chaperonin-mediated protein folding SO FASEB JOURNAL LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Ctr Adv Res Biotechnol, Rockville, MD 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 0892-6638 J9 FASEB J JI Faseb J. PD JUL 31 PY 1997 VL 11 IS 9 SU S MA 1080 BP A1042 EP A1042 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ZK302 UT WOS:000073305601565 ER PT J AU Zhang, M Fulcher, J Scofield, RA AF Zhang, M Fulcher, J Scofield, RA TI Rainfall estimation using artificial neural network group SO NEUROCOMPUTING LA English DT Article DE neural network set; generalised neural network set; neural network group; ANSER expert system; reasoning neural network; reasoning neural network group; satellite data; rainfall estimation ID CLASSIFICATION; MEMORY AB Recent artificial neural network research has focused on simple models, but such models have not proved very successful in describing complex systems. Neural network group theory is a step towards bridging this gap between simple models and complex systems. We first develop artificial neural network group theory, then proceed to show how neural network groups are able to approximate arty kind of piecewise continuous function, and to any degree of accuracy. These principles are then illustrated by way of an ANN expert system for rainfall estimation, It is shown that using this approach, rainfall estimates can be computed around 10 times faster than conventional techniques, and with average errors for the overall precipitation event falling below 10%. Based on our work to date, we conclude that neural network group theory holds considerable potential for complex problem solving in various domains. C1 UNIV WOLLONGONG,DEPT COMP SCI,WOLLONGONG,NSW 2522,AUSTRALIA. UNIV WESTERN SYDNEY MACARTHUR,DEPT COMP & INFORMAT SYST,CAMPBELLTOWN,NSW 2560,AUSTRALIA. NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,SATELLITE APPLICAT LAB,WASHINGTON,DC 20233. UNIV WOLLONGONG,CTR INFORMAT TECHNOL RES,WOLLONGONG,NSW,AUSTRALIA. NR 26 TC 35 Z9 36 U1 3 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-2312 J9 NEUROCOMPUTING JI Neurocomputing PD JUL 31 PY 1997 VL 16 IS 2 BP 97 EP 115 DI 10.1016/S0925-2312(96)00022-7 PG 19 WC Computer Science, Artificial Intelligence SC Computer Science GA XN617 UT WOS:A1997XN61700002 ER PT J AU Colucci, DM McKenna, GB Filliben, JI Lee, A Curliss, DB Bowman, KB Russell, JD AF Colucci, DM McKenna, GB Filliben, JI Lee, A Curliss, DB Bowman, KB Russell, JD TI Isochoric and isobaric glass formation: Similarities and differences SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE glass transition; isobaric; isochoric; polymer; poly(carbonate); PVT behavior; free volume theory ID VOLUME-TEMPERATURE RELATIONSHIPS; ENTHALPY RELAXATION; AMORPHOUS POLYMERS; PRIOR HISTORY; TRANSITION REGION; PRESSURE; POLYSTYRENE AB Pressure-volume-temperature (PVT) studies were performed on a glass-forming polymer, poly(carbonate) (PC), under both isobaric and isochoric (constant volume) conditions. An isochoric glass transition was observed and the formation points were found to be consistent with those obtained isobarically. Although the isobaric and isochoric responses were, as expected, the same in the rubbery state, the glassy state values were found to be different and dependent upon the glass formation history. The isobaric data exhibited larger changes in going from the rubber to the glass, hence a ''stronger'' glass transition, than did the isochoric data. Inserting the experimental values for the thermal expansion coefficient alpha and isothermal compressibility beta, into appropriate thermodynamic relations, measures of the strength of each transition are defined. Strength estimates based on literature values of alpha and beta are compared to the experimental measures of the isochoric and isobaric transitions. In addition, both the isobaric and isochoric PVT results were analyzed in terms of the Fox and Flory free volume theory which assumes that the glass transition is an iso-free volume state. While the isobaric results were consistent with the Fox and Flory theory, the isochoric results were not consistent with the idea of an iso-free volume glass transition. (C) 1997 John Wiley & Sons, Inc. C1 NIST, STAT ENGN DIV, GAITHERSBURG, MD 20899 USA. MICHIGAN STATE UNIV, DEPT MECH & MAT SCI, E LANSING, MI 48824 USA. USAF, WRIGHT LAB, MAT DIRECTORATE, WRIGHT PATTERSON AFB, OH 45433 USA. RP NIST, DIV POLYMERS, GAITHERSBURG, MD 20899 USA. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 56 TC 40 Z9 40 U1 2 U2 12 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0887-6266 EI 1099-0488 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD JUL 30 PY 1997 VL 35 IS 10 BP 1561 EP 1573 DI 10.1002/(SICI)1099-0488(19970730)35:10<1561::AID-POLB8>3.0.CO;2-U PG 13 WC Polymer Science SC Polymer Science GA XH937 UT WOS:A1997XH93700008 ER PT J AU Cess, RD Zhang, MH Potter, GL Alekseev, V Barker, HW Bony, S Colman, RA Dazlich, DA DelGenio, AD Deque, M Dix, MR Dymnikov, V Esch, M Fowler, LD Fraser, JR Galin, V Gates, WL Hack, JJ Ingram, WJ Kiehl, JT Kim, Y LeTreut, H Liang, XZ McAvaney, BJ Meleshko, VP Morcrette, JJ Randall, DA Roeckner, E Schlesinger, ME Sporyshev, PV Taylor, KE Timbal, B Volodin, EM Wang, W Wang, WC Wetherald, RT AF Cess, RD Zhang, MH Potter, GL Alekseev, V Barker, HW Bony, S Colman, RA Dazlich, DA DelGenio, AD Deque, M Dix, MR Dymnikov, V Esch, M Fowler, LD Fraser, JR Galin, V Gates, WL Hack, JJ Ingram, WJ Kiehl, JT Kim, Y LeTreut, H Liang, XZ McAvaney, BJ Meleshko, VP Morcrette, JJ Randall, DA Roeckner, E Schlesinger, ME Sporyshev, PV Taylor, KE Timbal, B Volodin, EM Wang, W Wang, WC Wetherald, RT TI Comparison of the seasonal change in cloud-radiative forcing from atmospheric general circulation models and satellite observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BUDGET EXPERIMENT DATA; CLIMATE; EARTH; ABSORPTION AB We compare seasonal changes in cloud-radiative forcing (CRF) at the top of the atmosphere from 18 atmospheric general circulation models, and observations from the Earth Radiation Budget Experiment (ERBE). To enhance the CRF signal and suppress interannual variability, we consider only zonal mean quantities for which the extreme months (January and July), as well as the northern and southern hemispheres, have been differenced. Since seasonal variations of the shortwave component of CRF are caused by seasonal changes in both cloudiness and solar irradiance, the latter was removed. In the ERBE data, seasonal changes in CRF are driven primarily by changes in cloud amount. The same conclusion applies to the models. The shortwave component of seasonal CRF is a measure of changes in cloud amount at all altitudes, while the longwave component is more a measure of upper level clouds. Thus important insights into seasonal cloud amount variations of the models have been obtained by comparing both components, as generated by the models, with the satellite data. For example, in 10 of the 18 models the seasonal oscillations of zonal cloud patterns extend too far poleward by one latitudinal grid. C1 RUSSIAN ACAD SCI, OTDELENIE CHISLITELNOI MATEMATIKI, MOSCOW 117334, RUSSIA. CANADIAN CLIMATE CTR, DOWNSVIEW, ON M3H 5T4, CANADA. METEOROL DYNAM LAB, F-75231 PARIS 05, FRANCE. BUR METEOROL RES CTR, MELBOURNE, VIC 3001, AUSTRALIA. COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. NATL CTR RECH METEOROL, F-31057 TOULOUSE, FRANCE. CSIRO, DIV ATMOSPHER RES, ASPENDALE, VIC 3195, AUSTRALIA. MAX PLANCK INST METEOROL, D-21046 HAMBURG, GERMANY. LAWRENCE LIVERMORE NATL LAB, PROGRAM CLIMATE MODEL DIAG & INTERCOMPARISON, LIVERMORE, CA 94550 USA. NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. UK METEOROL OFF, HADLEY CTR CLIMATE PREDICT & RES, BRACKNELL RG12 2SY, BERKS, ENGLAND. SUNY ALBANY, ATMOSPHER SCI RES CTR, ALBANY, NY 12205 USA. GLAVNAYA GEOFIZICHESKAYA OBSERV IMENI AI VOEIKOVA, ST PETERSBURG 194018, RUSSIA. EUROPEAN CTR MEDIUM RANGE WEATHER FORECASTS, READING RG2 9AX, BERKS, ENGLAND. UNIV ILLINOIS, DEPT ATMOSPHER SCI, URBANA, IL 61801 USA. PRINCETON UNIV, NOAA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08540 USA. RP SUNY STONY BROOK, MARINE SCI RES CTR, INST TERR & PLANETARY ATMOSPHERES, STONY BROOK, NY 11794 USA. RI alexeev, vladimir/B-2234-2010; Taylor, Karl/F-7290-2011; Del Genio, Anthony/D-4663-2012; Dix, Martin/A-2334-2012; Randall, David/E-6113-2011; Meleshko, Valentin/D-2157-2016; Sporyshev, Petr/P-7323-2015; OI alexeev, vladimir/0000-0003-3519-2797; Taylor, Karl/0000-0002-6491-2135; Del Genio, Anthony/0000-0001-7450-1359; Dix, Martin/0000-0002-7534-0654; Randall, David/0000-0001-6935-4112; Sporyshev, Petr/0000-0002-4047-8178; Bony, Sandrine/0000-0002-4791-4438 NR 19 TC 38 Z9 39 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1997 VL 102 IS D14 BP 16593 EP 16603 DI 10.1029/97JD00927 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN384 UT WOS:A1997XN38400014 ER PT J AU Ferraro, RR AF Ferraro, RR TI Special sensor microwave imager derived global rainfall estimates for climatological applications SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PRECIPITATION; SSM/I; RETRIEVAL; CLOUD; MODEL; LAND AB Global monthly rainfall estimates have been produced from over 8 years of measurements from the Defense Meteorological Satellite Program series of special sensor microwave/imagers (SSM/Is) and are analyzed to depict seasonal, annual, and interannual variability. This SSM/I product is one of the components of the blended Global Precipitation Climatology Project rainfall climatology. The primary algorithm used is an 85 GHz scattering-based algorithm over land, and a combined 85 GHz scattering and 19/37 GHz emission over ocean, both of which have been calibrated with ground-based radar data. Errors associated with the SSM/I derived monthly rainfall are characterized through comparisons with various gauge-based, climatological, and other satellite-derived rainfall estimates. During the period of June 1990 to December 1991 the 85 GHz channels aboard the SSM/I failed, so no monthly rainfall estimates are available. An alternative algorithm, using a newly developed 37 GHz scattering approach over land, and emission only over ocean, was developed to obtain a continuous record of rainfall estimates for the entire SSM/I time series. Although the 37 GHz scattering algorithm is sensitive to rain rates in excess of 8 mm/h, the correlation between the 37 and 85 GHz monthly estimates over land can be as high as 0.9 (but varies regionally) when comparing both approaches during a period of useable 85 GHz measurements. The error in the monthly rainfall using this algorithm is typically larger in comparison with measurements from rain gauges. Over ocean the emission only algorithm produces a lesser amount of rain than the scattering-based algorithm, most likely attributed to the lack of a proper beam-filling correction. During the period of January 1992 to the present there were two SSM/I satellites in full. operation, with sampling times of approximately 0600/1800 and 1000/2200 LT. Comparisons between the single and dual satellites are made and are compared with gauge data sets. In general, it is found that the dual-satellite estimates reduce the RMS errors, although the improvements are both regionally and seasonally dependent. RP NOAA, NESDIS,OFF RES & APPLICAT,E RA2,5200 AUTH RD, ROOM 601Q, CAMP SPRINGS, MD 20746 USA. RI Ferraro, Ralph/F-5587-2010 OI Ferraro, Ralph/0000-0002-8393-7135 NR 45 TC 163 Z9 167 U1 1 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1997 VL 102 IS D14 BP 16715 EP 16735 DI 10.1029/97JD01210 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN384 UT WOS:A1997XN38400022 ER PT J AU Lopez, RE Aubagnac, JP AF Lopez, RE Aubagnac, JP TI The lightning activity of a hailstorm as a function of changes in its microphysical characteristics inferred from polarimetric radar observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DOPPLER RADAR; THUNDERSTORMS; HAIL; ICE; ELECTRIFICATION; PRECIPITATION; STORMS; WATER AB The progression of cloud-to-ground (CG) lightning activity in an Oklahoma hailstorm with well-developed supercell organization is related to changes in the microphysical characteristics of the storm as inferred from polarimetric radar observations. A decision tree based on the observed values of radar reflectivity Z(H), differential reflectivity Z(DR), and specific differential phase K-DP is used to identify regions in the storm containing graupel, hail, supercooled liquid water, and rain. Mixing ratios of graupel/hail and liquid water are obtained in terms of Z(H), Z(DR), and K-DP. One of the objectives of the study is to relate the development of graupel aloft, and the descent of graupel and hail, to fluctuations in CG lightning production. The results indicate that the development of graupel above the freezing level is related to the overall increase and decrease in the production of CG flashes (probably by providing the negative charge necessary for the flashes). However, it is the fluctuating descent of small hail below the height of the negatively charged graupel region that is correlated with the three or four pulses in the CG lightning activity (apparently by producing the electric bias needed for the discharge of the graupel layers aloft). C1 UNIV OKLAHOMA, COOPERAT INST MESOSCALE METEOROL STUDIES, NORMAN, OK 73019 USA. RP NOAA, NATL SEVERE STORMS LAB, 1313 HALLEY CIRCLE, NORMAN, OK 73069 USA. NR 23 TC 21 Z9 24 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1997 VL 102 IS D14 BP 16799 EP 16813 DI 10.1029/97JD00645 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN384 UT WOS:A1997XN38400029 ER PT J AU Husar, RB Prospero, JM Stowe, LL AF Husar, RB Prospero, JM Stowe, LL TI Characterization of tropospheric aerosols over the oceans with the NOAA advanced very high resolution radiometer optical thickness operational product SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID TROPICAL NORTH-ATLANTIC; EASTERN-UNITED-STATES; SCALE AIR-POLLUTION; SAHARAN DUST; ATMOSPHERIC SULFUR; ANTHROPOGENIC AEROSOLS; SATELLITE MEASUREMENTS; MARINE ATMOSPHERE; GREENHOUSE GASES; TRACE-ELEMENTS AB The National Oceanic and Atmospheric Administration (NOAA) advanced very high resolution radiometer (AVHRR) is an instrument on a polar orbiting satellite that provides information on global aerosol distributions. The remote sensing algorithm is based on measurements of backscattered solar radiation which yield a measure of the ''radiatively equivalent'' aerosol optical thickness tau(sat)(A) (EAOT) over the oceans. Seasonally composited EAOT data for the period July 1989 to June 1991 reveal many spatially coherent plume-like patterns that can usually be interpreted in terms of known (or reasonably hypothesized) sources in association with climatological wind fields. The largest and most persistent areas of high EAOT values are associated with wind-blown dust and biomass burning sources; especially prominent are sources in Africa, the middle East, and the Asian subcontinent. Prominent plumes over the midlatitude North Atlantic are attributed to pollution emissions from North America and Europe. Large plumes attributed to pollution aerosols and dust from sources in Asia are clearly visible over the western and central North Pacific. On a global scale the annually averaged northern hemisphere EAOT values are about 1.7 times greater than those in the southern hemisphere. Considering each hemisphere separately, EAOT values in summer are about twice those in winter. Within the midlatitude band 30 degrees-60 degrees (i.e., where anthropogenic emissions are greatest) the summer/winter ratio is about 3. The temporal variability of monthly mean EAOT in specific ocean regions often shows characteristic seasonal patterns that are usually consistent with aerosol measurements made in the marine boundary layer. Nonetheless, there are features in the EAOT distributions that can not be readily interpreted at this time. The AVHRR EAOT distributions demonstrate that satellite products can serve as a useful tool for the planning and implementation of focused aerosol research programs and that they will be especially important in studies of climate-related processes. C1 WASHINGTON UNIV, CTR AIR POLLUT IMPACT & TREND ANAL, ST LOUIS, MO 63130 USA. NOAA, NESDID, NATL ENVIRONM SATELLITE DATA & INFORMAT SERV, WASHINGTON, DC 20233 USA. RP UNIV MIAMI, ROSENSTIEL SCH MARINE & ATMOSPHER SCI, 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA. RI Husar, Rudolf/A-9000-2009; OI Prospero, Joseph/0000-0003-3608-6160 NR 130 TC 515 Z9 523 U1 2 U2 37 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1997 VL 102 IS D14 BP 16889 EP 16909 DI 10.1029/96JD04009 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN384 UT WOS:A1997XN38400036 ER PT J AU Stowe, LL Ignatov, AM Singh, RR AF Stowe, LL Ignatov, AM Singh, RR TI Development, validation, and potential enhancements to the second-generation operational aerosol product at the national environmental satellite, data, and information service of the national oceanic and atmospheric administration SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OPTICAL-PROPERTIES; SAHARAN-DUST; AVHRR DATA; CLOUD; EQUATORIAL; RADIOMETER; THICKNESS; TURBIDITY; RETRIEVAL; ATLANTIC AB A revised (phase 2) single-channel algorithm for aerosol optical thickness, tau(SAT)(A), retrieval over oceans from radiances in channel 1 (0.63 mu m) of the advanced very high resolution radiometer (AVHRR) has been implemented at the National Oceanic and Atmospheric Administration's National Environmental Satellite Data and Information Service for the NOAA 14 satellite launched December 30, 1994. It is based on careful validation of its operational predecessor (phase 1 algorithm), implemented for NOAA 11 in 1989. Both algorithms scale the upward satellite radiances in cloud-free conditions to aerosol optical thickness using an updated radiative transfer model of the ocean and atmosphere. Application of the phase 2 algorithm to three matchup Sun-photometer and satellite data sets, one with NOAA 9 in 1988 and two with NOAA 11 in 1989 and 1991, respectively, show systematic error is less than 10%, with a random error of sigma(tau) approximate to 0.04. First results of tau(SAT)(A) retrievals from NOAA 14 using the phase 2 algorithm, and from checking its internal consistency, are presented. The potential two-channel (phase 3) algorithm for the retrieval of an aerosol size parameter, such as the Junge size distribution exponent, by adding either channel 2 (0.83 mu m) from the current AVHRR instrument, or a 1.6-mu m channel to be available on the Tropical Rainfall Measurement Mission and the NOAA-KLM satellites by 1997 is under investigation. The possibility of using this additional information in the retrieval of a more accurate estimate of aerosol optical thickness is being explored. C1 SM SYST & RES CORP INC, BOWIE, MD 20716 USA. RP NOAA, NATL ENVIRONM SATELLITE DATA & INFORMAT SERV, OFF RES & APPLICAT, E-RA11, NSC ROOM 711E, WASHINGTON, DC 20233 USA. RI Ignatov, Alexander/F-5594-2010 OI Ignatov, Alexander/0000-0002-7463-5944 NR 47 TC 198 Z9 209 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1997 VL 102 IS D14 BP 16923 EP 16934 DI 10.1029/96JD02132 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN384 UT WOS:A1997XN38400038 ER PT J AU Clark, DK Gordon, HR Voss, KJ Ge, Y Broenkow, W Trees, C AF Clark, DK Gordon, HR Voss, KJ Ge, Y Broenkow, W Trees, C TI Validation of atmospheric correction over the oceans SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ZONE COLOR SCANNER; RADIANCE DISTRIBUTION; DIFFUSE-REFLECTANCE; PHASE FUNCTION; WATER; RETRIEVAL; EXTINCTION; WHITECAPS; SYSTEM; LIDAR AB By validation of atmospheric correction, we mean quantification of the uncertainty expected to be associated with the retrieval of the water-leaving radiance from the measurement of the total radiance exiting the ocean-atmosphere system. This uncertainty includes that associated with the measurement or estimation of auxiliary data required for the retrieval process, for example, surface wind speed, surface atmospheric pressure, and total ozone concentration. For a definitive validation this quantification should be carried out over the full range of atmospheric types expected to be encountered. However, funding constraints require that the individual validation campaigns must be planned to address the individual components of the atmospheric correction algorithm believed to represent the greatest potential sources of error. In this paper we develop a strategy for validation of atmospheric correction over the oceans that is focused on EOS/MODIS. We also provide a description of the instrumentation and methods to be used in the implementation of the plan. C1 SAN JOSE STATE UNIV, MOSS LANDING MARINE LABS, MOSS LANDING, CA 95039 USA. RES & DATA CORP, GREENBELT, MD 20770 USA. UNIV MIAMI, DEPT PHYS, CORAL GABLES, FL 33124 USA. SAN DIEGO STATE UNIV, CHORS, SAN DIEGO, CA 92120 USA. RP NOAA, NESDIS, CAMP SPRINGS, MD 20746 USA. RI Voss, Kenneth /A-5328-2013 OI Voss, Kenneth /0000-0002-7860-5080 NR 47 TC 123 Z9 124 U1 2 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1997 VL 102 IS D14 BP 17209 EP 17217 DI 10.1029/96JD03345 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN384 UT WOS:A1997XN38400058 ER PT J AU Herzler, J Manion, JA Tsang, W AF Herzler, J Manion, JA Tsang, W TI Single-pulse shock tube studies of the decomposition of ethoxy compounds SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MECHANISM AB Tetraethyl orthocarbonate (TEOC), diethyl carbonate (DEC), and diethoxymethane (DEM) have been decomposed in single-pulse shock tube experiments. TEOC decomposes to give DEC, ethylene, and ethanol as organic products, while DEC results in only the latter two, In both cases the ethylene to ethanol ratio is equal to 1, and the mechanisms appear to involve molecular eliminations, The rate expressions for the initial processes are the following: k(TEOC --> products) = 10(13.91+/-0.14) exp((-27 529 +/- 348)K/T) s(-1), T = 1005-1180 K; k(DEC --> C2H5OCO2H + C2H4) = 10(12.03+/-0.11) exp((-23 290 +/- 26 7 K/T) s(-1), T = 955-1095 K. The listed uncertainties are one standard deviation. DEM decomposes more slowly than the other two compounds. For each DEM reacted, 1.2 ethylene and 0.5 ethanol are produced. Methane and ethane are also observed as products. The mechanism is postulated to involve both molecular and bond-breaking channels. It is concluded that ethanol arises only through the molecular channel, and on this basis the following rate expressions have been derived: k(DEM --> products) = 10(15.93+/-0.15) exp((-36 179 +/- 403 K/T) s(-1), T = 1150-1260 K; k(DEM --> ethanol + products) = 10(15.07+/-0.45) exp((-34 517 +/- 1090 K/T) s(-1); k(DEM --> ethyl + OCH2OC2H5) = 10(16.32+/-0.45) exp((-38 214 +/- 1160 K/T) s(-1). The results are compared with those dealing with the stability of analogous ethers, esters, and silicon compounds. For carbon compounds the addition of ethoxy groups to the compound destabilizes the molecule. It is further concluded that rate data on the molecular decompositions of ethoxy carbon compounds cannot be easily extrapolated to silicon-containing species. C1 NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. NR 18 TC 10 Z9 10 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 24 PY 1997 VL 101 IS 30 BP 5494 EP 5499 DI 10.1021/jp970653a PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XM730 UT WOS:A1997XM73000014 ER PT J AU Herzler, J Manion, JA Tsang, W AF Herzler, J Manion, JA Tsang, W TI Single-pulse shock tube study of the decomposition of tetraethoxysilane and related compounds SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TETRAMETHYL ORTHOSILICATE; GAS-PHASE; MECHANISM; KINETICS; TEOS AB Tetraethoxysilane (TEOS) has been decomposed in single-pulse shock tube experiments over the temperature range 1160-1285 K and pressures of about 150 kPa (1.5 bar). The main observed products are ethylene and ethanol. The yields of these products as a percentage of decomposed TEOS increase with temperature. Studies have also been carried out with tetra-n-propoxysilane (TPOS), dimethyldiethoxysilane (DMDEOS), and trimethylethoxysilane (TMEOS). Evidence is presented that in all cases the main initial reaction is a 1,2-elimination to form the olefin and the corresponding silanol. A smaller contribution from C-C bond-breaking channels is also observed. In combination with lower temperature results and the thermochemistry, the following rate expressions for the elementary processes are recommended: k[TEOS --> C2H4 + HOSi(OC2H5)(3)] = 1.04 x 10(10)T(1.1) exp(-30 950 K/T) s(-1); k[TEOS --> CH3 + CH2OSi(OC2H5)(3)] = 4 x 10(17) exp(-43 300 K/T) s(-1). The observed ethanol product is postulated to arise from decomposition of the silanol in a gas phase reaction. A kinetic model which quantitatively accounts for the observed products in the decomposition of TEOS, DMDEOS, and TMEOS has been developed. The model includes radical reactions as well as molecular reactions of the silanol and subsequently formed products, including silicates and silyl acids. The model requires an activation energy of less than or equal to 200 kJ mol(-1) for the reaction which forms ethanol from the silanol. Such a low barrier is apparently at odds with recently calculated values for the thermochemistry of some silicon compounds. C1 NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. NR 12 TC 31 Z9 31 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 24 PY 1997 VL 101 IS 30 BP 5500 EP 5508 DI 10.1021/jp9706543 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XM730 UT WOS:A1997XM73000015 ER PT J AU Turnipseed, AA Gilles, MK Burkholder, JB Ravishankara, AR AF Turnipseed, AA Gilles, MK Burkholder, JB Ravishankara, AR TI Kinetics of the IO radical .1. Reaction of IO with ClO SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MARINE ATMOSPHERE; OZONE DEPLETION; SELF-REACTION; BRO; IODINE; PHOTOCHEMISTRY; MECHANISM; PRODUCT; CF3I AB The rate coefficient for the IO + ClO --> products (5) reaction was measured by coupling discharge flow and pulsed laser-induced fluorescence techniques. Rate coefficients were measured from 200 to 362 K by monitoring the temporal profile of IO in an excess of ClO The rate coefficient is described by the expression: k(5)(T) = (5.1 +/- 1.7) x 10-(12) exp[(280 +/- 80)/T] cm(3) molecule(-1) s(-1) where the quoted uncertainties include estimated systematic errors, Atomic iodine was identified as a major product of reaction 5. A branching ratio of Phi = 0.14 +/- 0.04 at 298 K was obtained for the sum of channels which do not produce I atoms. C1 NOAA,AERON LAB,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 33 TC 27 Z9 27 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 24 PY 1997 VL 101 IS 30 BP 5517 EP 5525 DI 10.1021/jp970914g PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XM730 UT WOS:A1997XM73000017 ER PT J AU Gilles, MK Turnipseed, AA Burkholder, JB Ravishankara, AR Solomon, S AF Gilles, MK Turnipseed, AA Burkholder, JB Ravishankara, AR Solomon, S TI Kinetics of the IO radical .2. Reaction of IO with BrO SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID OZONE DEPLETION; MECHANISM; IODINE AB The rate coefficient for the IO + BrO --> products (1) reaction was measured using pulsed laser photolysis with a discharge flow tube for radical production and pulsed laser-induced fluorescence and UV absorption for detection of IO and BrO radicals, respectively. Reaction 1 was studied under pseudo-first-order conditions in IO with an excess of BrO between 204 and 388 K at total pressures of 6-15 Torr. The Arrhenius expression obtained for non-iodine atom producing channels is k(la)(T) = (2.5 +/- 1.0) x 10(-11) exp[(260 +/- 100)/T] cm(3) molecule(-1) s(-1) independent of pressure. The rate coefficient for the reaction BrO + BrO --> products (2) and the UV absorption cross sections of BrO as a function of temperature were also determined as part of this study. The implications of these results to the loss rate of stratospheric ozone are discussed. C1 NOAA,AERON LAB,ERL,R E AL2,BOULDER,CO 80303. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 28 TC 46 Z9 46 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 24 PY 1997 VL 101 IS 30 BP 5526 EP 5534 DI 10.1021/jp9709159 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XM730 UT WOS:A1997XM73000018 ER PT J AU Holmes, TM Nichols, SB McChesney, T AF Holmes, TM Nichols, SB McChesney, T TI Tornado-associated fatalities - Arkansas, 1997 (Reprinted from MMWR, vol 46, pg 412-416, 1997) SO JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION LA English DT Reprint ID INJURIES C1 AMER RED CROSS,DISASTER HLTH SERV,FALLS CHURCH,VA. US DEPT COMMERCE,NOAA,NATL WEATHER SERV,WASHINGTON,DC 20230. NATL CTR CHRON DIS PREVENT & HLTH PROMOT,DIV NUTR & PHYS ACTIV,MATERNAL & CHILD HLTH BRANCH,ATLANTA,GA 30333. CTR DIS CONTROL,NATL CTR ENVIRONM HLTH,DIV ENVIRONM HAZARDS & HLTH EFFECTS,HLTH STUDIES BRANCH,ATLANTA,GA 30333. RP Holmes, TM (reprint author), ARKANSAS DEPT HLTH,LITTLE ROCK,AR 72205, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU AMER MEDICAL ASSOC PI CHICAGO PA 515 N STATE ST, CHICAGO, IL 60610 SN 0098-7484 J9 JAMA-J AM MED ASSOC JI JAMA-J. Am. Med. Assoc. PD JUL 23 PY 1997 VL 278 IS 4 BP 279 EP 280 PG 2 WC Medicine, General & Internal SC General & Internal Medicine GA XL059 UT WOS:A1997XL05900012 ER PT J AU Zielinski, RG Kline, SR Kaler, EW Rosov, N AF Zielinski, RG Kline, SR Kaler, EW Rosov, N TI A small-angle neutron scattering study of water in carbon dioxide microemulsions SO LANGMUIR LA English DT Article ID PROPANE AB Phase behavior and small angle neutron scattering (SANS) experiments were performed on mixtures of D2O/CO2/ammonium carboxylate perfluoropolyether (PFPE) surfactant as a function of pressure (192-287 bar) and D2O composition (0.8-2.0 wt %) at 35 degrees C. SANS measurements provided direct evidence of water-swollen inverted micelles in CO2. At a constant PFPE concentration of 2.1 wt % in CO2, the microemulsion core radius increased from 20 to 36 Angstrom as the D2O concentration increased from 0.8 to 2.0 wt %. For a constant water concentration, parameters extracted from model fits of the SANS spectra indicated that as the phase boundary was approached on reducing pressure, micellar structure remained essentially unchanged, while critical fluctuations increased. C1 UNIV DELAWARE,DEPT CHEM ENGN,CTR MOL & ENGN THERMODYNAM,NEWARK,DE 19716. NIST,CTR NEUTRON RES,GAITHERSBURG,MD 20899. NR 19 TC 110 Z9 113 U1 1 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUL 23 PY 1997 VL 13 IS 15 BP 3934 EP 3937 DI 10.1021/la9700836 PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA XM642 UT WOS:A1997XM64200007 ER PT J AU Anderson, DT Davis, S Nesbitt, DJ AF Anderson, DT Davis, S Nesbitt, DJ TI Sequential solvation of HCl in argon: High resolution infrared spectroscopy of ArnHCl (n=1, 2, 3) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BOUND-STATE CALCULATIONS; SIGMA-BENDING VIBRATION; DER-WAALS CLUSTERS; LASER SPECTROSCOPY; AR-HCL; INTERMOLECULAR FORCES; ROTATIONAL SPECTRUM; SUPERSONIC JET; RED SHIFTS; ARHCL AB High-resolution near-infrared spectra of the nu(HCl)=1<--0 fundamental stretch in Ar2HCl and Ar3HCl have been characterized using a slit-jet infrared spectrometer. Analysis of the jet-cooled, rotationally resolved spectra (i) permits unambiguous identification of the cluster size, (ii) provides vibrationally averaged geometries in the nu(HCl)=1 excited state, and (iii) allows the vibrational shift of the HCl chromophore to be measured as a function of the number of Ar atoms in the complex. The equilibrium structures of ArnHCl (n=1-3) clusters calculated using accurate Ar-Ar and Ar-HCl pair potentials are consistent with the vibrationally averaged structures inferred spectroscopically. The vibrational red-shifts for ArnHCl (n=1-3) reflect a near-linear dependence on the number of Ar atoms, which is qualitatively reproduced by simple classical calculations on nu(HCl)=0 and 1 pairwise additive potential surfaces. Theoretical predictions of the ArnHCl red-shifts in a fee lattice indicate good agreement with experimental matrix results. However, to achieve this asymptotic limit requires up to n approximate to 54 Ar atoms; this underscores a clear sensitivity to non-nearest neighbor Ar-HCl interactions significantly outside the first solvation shell. Finally, for smaller ArnHCl clusters with only one solvation shell (n=12), the potentials predict an energetic preference for HCl in surface vs interior sites. Analysis indicates that this effect is predominantly due to Ar/HCl size mismatch, which destabilizes the nearest neighbor Ar shell for HCl solvated in the center of the cluster. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Anderson, DT (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 48 TC 41 Z9 41 U1 0 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 22 PY 1997 VL 107 IS 4 BP 1115 EP 1127 DI 10.1063/1.474458 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XL402 UT WOS:A1997XL40200010 ER PT J AU Burt, EA Ghrist, RW Myatt, CJ Holland, MJ Cornell, EA Wieman, CE AF Burt, EA Ghrist, RW Myatt, CJ Holland, MJ Cornell, EA Wieman, CE TI Coherence, correlations, and collisions: What one learns about Bose-Einstein condensates from their decay SO PHYSICAL REVIEW LETTERS LA English DT Article AB We have used three-body recombination rates as a sensitive probe of the statistical correlations between atoms in Bose-Einstein condensates (BEC) and in ultracold noncondensed dilute atomic gases. We infer that density fluctuations are suppressed in the BEC samples. We measured the three-body recombination rate constants for condensates and cold noncondensates from number loss in the F = 1,m(f) = -1 hyperfine state of Rb-87. The ratio of these is 7.4(2.6) which agrees with the theoretical factor of 3! and demonstrates that condensate atoms are less bunched than noncondensate atoms. C1 UNIV COLORADO, DEPT PHYS, BOULDER, CO 80309 USA. RP UNIV COLORADO, NATL INST STAND & TECHNOL, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. NR 31 TC 349 Z9 350 U1 4 U2 25 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 21 PY 1997 VL 79 IS 3 BP 337 EP 340 DI 10.1103/PhysRevLett.79.337 PG 4 WC Physics, Multidisciplinary SC Physics GA XL549 UT WOS:A1997XL54900002 ER PT J AU Burns, TJ Davies, MA AF Burns, TJ Davies, MA TI Nonlinear dynamics model for chip segmentation in machining SO PHYSICAL REVIEW LETTERS LA English DT Article ID PLASTIC-DEFORMATION; SHEAR BAND; INSTABILITY; SIMULATION; CRITERION; MECHANISM; FLOW AB We have developed a new model for chip formation in machining which includes a mechanism for thermomechanical feedback. This leads to an interpretation of metal cutting as a process which is similar in many ways to an open chemical reactor. As the cutting speed is increased, there is a Hopf bifurcation, which explains the observed change from continuous to segmented chip formation. C1 NATL INST STAND & TECHNOL,AUTOMATED PROD TECHNOL DIV,MFG ENGN LAB,GAITHERSBURG,MD 20899. RP Burns, TJ (reprint author), NATL INST STAND & TECHNOL,MATH & COMPUTAT SCI DIV,INFORMAT TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 27 TC 33 Z9 33 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 21 PY 1997 VL 79 IS 3 BP 447 EP 450 DI 10.1103/PhysRevLett.79.447 PG 4 WC Physics, Multidisciplinary SC Physics GA XL549 UT WOS:A1997XL54900029 ER PT J AU Svalgaard, M Gilbert, SL AF Svalgaard, M Gilbert, SL TI Stability of short, single-mode erbium-doped fiber lasers SO APPLIED OPTICS LA English DT Article DE fiber lasers; Bragg gratings; frequency stability; intensity noise; relaxation oscillations ID FREQUENCY AB We conducted a detailed study of the stability of short, erbium-doped fiber lasers fabricated with two UV-induced Bragg gratings written into the doped fiber. We find that the relative intensity noise of single-longitudinal-mode fiber grating lasers is approximately 3 orders of magnitude lower than that of a single-frequency 1.523-mu m helium-neon laser. The frequency noise spectrum contains few resonances, none of which exceeds 0.6 kHz/Hz(1/2) rms; the integrated rms frequency noise from 50 Hz to 63 kHz is 36 kHz. We also demonstrate a simple method for monitoring the laser power and number of oscillating modes during laser fabrication. RP NATL INST STAND & TECHNOL, 325 BROADWAY, BOULDER, CO 80303 USA. NR 9 TC 7 Z9 7 U1 1 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 20 PY 1997 VL 36 IS 21 BP 4999 EP 5005 DI 10.1364/AO.36.004999 PG 7 WC Optics SC Optics GA XL474 UT WOS:A1997XL47400014 PM 18259307 ER PT J AU Holland, EA Braswell, BH Lamarque, JF Townsend, A Sulzman, J Muller, JF Dentener, F Brasseur, G Levy, H Penner, JE Roelofs, GJ AF Holland, EA Braswell, BH Lamarque, JF Townsend, A Sulzman, J Muller, JF Dentener, F Brasseur, G Levy, H Penner, JE Roelofs, GJ TI Variations in the predicted spatial distribution of atmospheric nitrogen deposition and their impact on carbon uptake by terrestrial ecosystems SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID 3-DIMENSIONAL MODEL; FOREST DECLINE; SOIL; NOX; EMISSIONS; CYCLE; CHEMISTRY; BIOSPHERE; GROWTH; OZONE AB Widespread mobilization of nitrogen into the atmosphere from industry, agriculture, and biomass burning and its subsequent deposition have the potential to alleviate nitrogen limitation of productivity in terrestrial ecosystems, and may contribute to enhanced terrestrial carbon uptake. To evaluate the importance of the spatial distribution of nitrogen deposition for carbon uptake and to better quantify its magnitude and uncertainty NOy-N deposition fields from five different three-dimensional chemical models, GCTM, GRANTOUR, IMAGES, MOGUNTIA, and ECHAM were used to drive NDEP, a perturbation model of terrestrial carbon uptake. Differences in atmospheric sources of NOx-N, transport, resolution, and representation of chemistry, contribute to the distinct spatial patterns of nitrogen deposition on the global land surface; these differences lead to distinct patterns of carbon uptake that vary between 0.7 and 1.3 Gt C yr(-1) globally. Less than 10% of the nitrogen was deposited on forests which were most able to respond with increased carbon storage because of the wide C:N ratio of wood as well as its long lifetime. Addition of NHx-N to NOy-N deposition, increased global terrestrial carbon storage to between 1.5 and 2.0 Gt C yr(-1), while the ''missing terrestrial sink'' is quite similar in magnitude. Thus global air pollution appears to be an important influence on the global carbon cycle. If N fertilization of the terrestrial biosphere accounts for the ''missing'' C sink or a substantial portion of it, we would expect significant reductions in its magnitude over the next century as terrestrial ecosystems become N saturated and O-3 pollution expands. C1 UNIV NEW HAMPSHIRE, DURHAM, NH 03824 USA. UNIV COLORADO, BOULDER, CO 80309 USA. BELGIAN INST SPACE AERON, B-1180 BRUSSELS, BELGIUM. AGR UNIV WAGENINGEN, DEPT AIR QUAL, NL-6700 EV WAGENINGEN, NETHERLANDS. UNIV MICHIGAN, ANN ARBOR, MI 48109 USA. INST MARINE & ATMOSPHER RES, NL-3584 CC UTRECHT, NETHERLANDS. GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08542 USA. RP Holland, EA (reprint author), NATL CTR ATMOSPHER RES, POB 3000, BOULDER, CO 80307 USA. RI Penner, Joyce/J-1719-2012; Lamarque, Jean-Francois/L-2313-2014; Braswell, Bobby/D-6411-2016 OI Lamarque, Jean-Francois/0000-0002-4225-5074; Braswell, Bobby/0000-0002-4061-9516 NR 82 TC 204 Z9 225 U1 2 U2 53 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1997 VL 102 IS D13 BP 15849 EP 15866 DI 10.1029/96JD03164 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XM347 UT WOS:A1997XM34700001 ER PT J AU Bakwin, PS Hurst, DF Tans, PP Elkins, JW AF Bakwin, PS Hurst, DF Tans, PP Elkins, JW TI Anthropogenic sources of halocarbons, sulfur hexafluoride, carbon monoxide, and methane in the southeastern United States SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NITROUS-OXIDE; ATMOSPHERE; EMISSIONS; CHLOROFORM; RELEASE; CH3CCL3; TRENDS; OH AB Mixing ratios of several radiatively active and ozone depleting trace gases were measured at 1-hour intervals from December 1994 to August 1996 at 496 m above the ground on a communications tower in eastern North Carolina. The time series show variability on a range of timescales, most apparently diurnal cycles, pollution episodes with synoptic time scale, seasonal cycles, and long-term trends. We focus on the pollution episodes and analyze the time series to reveal relationships between species in polluted air. These relationships are used to determine relative sources of the constituents on a regional scale. Using tetrachloroethene (C2Cl4) as a reference compound and assuming that the tower site is representative of the whole continent with respect to emissions ratios, we estimate source strengths of the other species for North America. For methyl chloroform (CH3CCl3) our emissions estimate:is in excellent accord with an estimate from industrial production figures, giving confidence in our methods and assumptions. For carbon monoxide (GO) our estimate also agrees very well with an independent estimate of North American sources based on national inventories. Sources of chlorofluorocarbons 11, 12, and 113 are much lower than expected from global emissions inventories, a finding that may indicate that the ratio of North American to global emissions of these compounds has dropped dramatically since the mid-1980s, as was indeed the case for CH3CCl3, or that emissions of these compounds have decreased more rapidly in recent years than industry estimates, or must likely both. We also estimate the North American source of sulfur hexafluoride (SF6). C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Bakwin, PS (reprint author), NOAA, CLIMATE MONITORING & DIAGNOST LAB, R E CG1, 325 BROADWAY, BOULDER, CO 80303 USA. RI Hurst, Dale/D-1554-2016 OI Hurst, Dale/0000-0002-6315-2322 NR 42 TC 42 Z9 43 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1997 VL 102 IS D13 BP 15915 EP 15925 DI 10.1029/97JD00869 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XM347 UT WOS:A1997XM34700006 ER PT J AU Stecher, HA Luther, GW MacTaggart, DL Farwell, SO Crosley, DR Dorko, WD Goldan, PD Beltz, N Krischke, U Luke, WT Thornton, DC Talbot, RW Lefer, BL Scheuer, EM Benner, RL Wu, JG Saltzman, ES Gallagher, MS Ferek, RJ AF Stecher, HA Luther, GW MacTaggart, DL Farwell, SO Crosley, DR Dorko, WD Goldan, PD Beltz, N Krischke, U Luke, WT Thornton, DC Talbot, RW Lefer, BL Scheuer, EM Benner, RL Wu, JG Saltzman, ES Gallagher, MS Ferek, RJ TI Results of the gas-phase sulfur intercomparison experiment (GASIE): Overview of experimental setup, results and general conclusions SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB Seven techniques for the field measurement of trace atmospheric SO2 were compared simultaneously over 1 month in 1994 using samples produced in situ by dynamic dilution. Samples included SO2 in dry air, in humid air, and in air with potentially interfering gases added, In addition, 2 days of comparison using diluted ambient air were conducted. Six of the seven techniques compared well, with good linear response and no serious interferences but with a range of calibration differences of about 50%, C1 UNIV FRANKFURT, ZENTRUM UMWELTFORSCH, D-60325 FRANKFURT, GERMANY. UNIV ALASKA, INST GEOPHYS, FAIRBANKS, AK 99701 USA. UNIV ALASKA, DEPT CHEM, FAIRBANKS, AK 99701 USA. SRI INT, MOL PHYS LAB, MENLO PK, CA 94025 USA. NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20889 USA. S DAKOTA SCH MINES & TECHNOL, GRAD OFF, RAPID CITY, SD 57701 USA. UNIV WASHINGTON, DEPT ATMOSPHER SCI, SEATTLE, WA 98195 USA. UNIV MIAMI, ROSENSTIEL SCH MARINE & ATMOSPHER SCI, MIAMI, FL 33149 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. UNIV NEW HAMPSHIRE, INST STUDY EARTH OCEANS & SPACE, DURHAM, NH 03824 USA. NOAA, AIR RESOURCES LAB, SILVER SPRING, MD 20910 USA. UNIV DELAWARE, COLL MARINE STUDIES, LEWES, DE 19958 USA. DREXEL UNIV, DEPT CHEM, PHILADELPHIA, PA 19104 USA. RI Luther, III, George/A-6384-2008; Lefer, Barry/B-5417-2012; Luke, Winston/D-1594-2016 OI Luther, III, George/0000-0002-0780-885X; Lefer, Barry/0000-0001-9520-5495; Luke, Winston/0000-0002-1993-2241 NR 4 TC 18 Z9 18 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1997 VL 102 IS D13 BP 16219 EP 16236 DI 10.1029/97JD01362 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XM347 UT WOS:A1997XM34700031 ER PT J AU MacTaggart, DL Farwell, SO Haakenson, TJ Bamesberger, WL Dorko, WD AF MacTaggart, DL Farwell, SO Haakenson, TJ Bamesberger, WL Dorko, WD TI Generation and evaluation of test gas mixtures for the gas-phase sulfur intercomparison experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INSTRUMENTATION; DILUTION; DIOXIDE AB The automated sulfur gas dilution system (ASGDS) was used during the Gas-Phase Sulfur Intercomparison Experiment (GASIE) to generate and analyze test gas mixtures containing pptv levels of SO2 in the presence of various suites of potential measurement interferent gases. These test gas mixtures were provided in a 100 standard liters per minute air matrix manifold, allowing simultaneous sampling by all seven intercomparison participants. The test gas mixtures were homogeneous within the 90-min test periods of the synthetic air phases of GASIE, allowing rigorous intercomparison of any two or more data points obtained during a given test period. A number of delivered SO2 concentrations were successfully replicated throughout the experiment, permitting the collection of a sufficient amount of data for statistical evaluation, The SO2 concentrations measured by the ASGDS quality control instrumentation agreed with values obtained by the intercomparison participants but were different from the set point values. C1 WASHINGTON STATE UNIV, LAB ATMOSPHER RES, PULLMAN, WA 99164 USA. NATL INST STAND & TECHNOL, CHEM B156, GAITHERSBURG, MD 20899 USA. UNIV IDAHO, DEPT CHEM, MOSCOW, ID 83844 USA. RP MacTaggart, DL (reprint author), S DAKOTA SCH MINES & TECHNOL, RAPID CITY, SD 57701 USA. NR 16 TC 4 Z9 4 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1997 VL 102 IS D13 BP 16237 EP 16245 DI 10.1029/96JD03676 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XM347 UT WOS:A1997XM34700032 ER PT J AU Luke, WT AF Luke, WT TI Evaluation of a commercial pulsed fluorescence detector for the measurement of low-level SO2 concentrations during the gas-phase sulfur intercomparison experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PER-TRILLION LEVELS; ATMOSPHERIC SULFUR; DIOXIDE; AIR AB A modified pulsed fluorescence (PF) detector (Thermo Environmental Instruments, Model 43s) was used to measure low levels of SO2 in a rigorous, blind intercomparison experiment (Gas-Phase Intercomparison Experiment (GASIE)). The PF detector was able to detect as little as 30 pptv SO2 in a 25-min sampling interval. The coefficients of variation for measurements of approximately 30, 60, 200, 330, and 600 pptv were approximately 40, 9, 6.5, 3, and 3%, respectively. Overall uncertainty of the measurements at 30 pptv approaches +/- 100%. As inferred from GASIE results, the response of the PF detector may be reduced (quenched) by approximately 7% and 15% at water vapor mixing ratios of 1 and 1.5 mole percent (relative humidities of 35-50% at 20-25 degrees C and 1 atm), respectively. These results are uncertain, however, due to lack of extensive data. Post-GASIE tests point to moderate interferences from NO (rejection ratio of 35), CS2 (rejection ratio of 20), and a number of highly fluorescent aromatic hydrocarbons such as benzene, toluene, o-xylene, m-xylene, p-xylene, m-ethyltoluene, ethylbenzene, and 1,2,4-trimethylbenzene. Rejection ratios for these compounds increase from approximately 17-123 to circa 1200-3800 as the sample flow rate is decreased from 2000 to 300 standard cubic centimeters per minute (seem), and the hydrocarbons are more efficiently removed by the instrument's proprietary hydrocarbon ''kicker'' membrane. At a flow rate of 300 seem and a pressure drop of 645 torr across the kicker, the interference from ppmv levels of many aromatic hydrocarbon was eliminated entirely. None of the tested interferants were removed by the carbonate-impregnated paper filter used to zero the instrument during GASIE; thus they induced no net response in the PF detector. These results illustrate the importance of using a selective zeroing method to scrub SO2 without removing potential interferants from the sample flow, thus preserving the overall composition of the sampling matrix. RP Luke, WT (reprint author), NOAA, AIR RESOURCES LAB,R E AR,SSMC-3,ROOM 3439, 1315 EAST WEST HIGHWAY, SILVER SPRING, MD 20910 USA. RI Luke, Winston/D-1594-2016 OI Luke, Winston/0000-0002-1993-2241 NR 20 TC 45 Z9 46 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1997 VL 102 IS D13 BP 16255 EP 16265 DI 10.1029/96JD03347 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XM347 UT WOS:A1997XM34700034 ER PT J AU Ferek, RJ Covert, PA Luke, W AF Ferek, RJ Covert, PA Luke, W TI Intercomparison of measurements of sulfur dioxide in ambient air by carbonate-impregnated filters and Teco pulsed-fluorescence analyzers SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB In two previous University of Washington field programs, airborne measurements of SO2 using carbonate-impregnated filters and a Teco pulsed-fluorescence analyzer showed excellent agreement over a range of ambient concentrations from 2 to 127 ppbv. As part of the Gas-Phase Sulfur Intercomparison Experiment (GASIE), ambient air, diluted fivefold to tenfold with zero air, was sampled in the concentration range of 0.02 to 4 ppbv. With the bulk of the measurements in the range of 40 to 230 parts per trillion by volume (pptv), agreement between the two techniques was again very good (regression equation: Teco = 1.07(filter)+ 4.5 pptv, r = 0.93). Using careful precleaning, impregnation, storage, and handling techniques for the filter substrates, at sub-100 pptv concentrations, the filter method is capable of an accuracy of better than +/-10% with a +/-7 pptv uncertainty (due to blank variability) for 6 m(3) samples. In addition, the Teco model 43 S is capable of rather precise measurements of sub-100 pptv concentrations (approximately +/-16 pptv) provided a suitable averaging time is employed (at least 10 min). C1 NOAA, AIR RESOURCES LAB, SILVER SPRING, MD 20910 USA. RP Ferek, RJ (reprint author), UNIV WASHINGTON, DEPT ATMOSPHER SCI, BOX 351640, SEATTLE, WA 98195 USA. RI Luke, Winston/D-1594-2016; OI Luke, Winston/0000-0002-1993-2241; Covert, Paul/0000-0002-7434-4995 NR 11 TC 7 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1997 VL 102 IS D13 BP 16267 EP 16272 DI 10.1029/96JD03587 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XM347 UT WOS:A1997XM34700035 ER PT J AU Talbot, RW Scheuer, EM Lefer, BL Luke, WT AF Talbot, RW Scheuer, EM Lefer, BL Luke, WT TI Measurements of sulfur dioxide during GASIE with the mist chamber technique SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PER-TRILLION LEVELS; ATMOSPHERIC SULFUR; CLOUD ALBEDO; ACETIC-ACIDS; CLIMATE; PHYTOPLANKTON; GASES; AIR AB This paper highlights the performance of the mist chamber/ion chromatography (MC/IC) technique for measuring atmospheric sulfur dioxide (SO2) during the Gas-Phase Sulfur Intercomparison Experiment (GASIE). The technique was found to be free of interference from CO, CO2, CH4, NOx, O-3, CH3SCH3, and H2O vapor. Repeated measurements at various mixing ratios of SO2 indicated that the coefficient of variation in the MC/IC measurement is 3-5% at 300-500 parts per trillion by volume (pptv), 4-7% at 150 pptv, 10% at 50 pptv, and as great as 20% near 20 pptv. In ambient air diluted five- to tenfold with zero air, the MC/IC technique tracked the other methods over the range of 30-3500 pptv. This agreement reinforced the conclusions obtained during the other test phases of GASIE. The MC/IC method has desirable features such as simplicity, small size, and weight of required equipment, sample integration times of 10 min or less, low pptv detection capabilities, and relatively modest implementation costs. In addition, a suite of important soluble gases can be measured simultaneously including nitric, formic, and acetic acids. C1 NOAA, AIR RESOURCES LAB, SILVER SPRING, MD 20910 USA. RP Talbot, RW (reprint author), UNIV NEW HAMPSHIRE, INST STUDY EARTH OCEANS & SPACE, MORSE HALL, DURHAM, NH 03824 USA. RI Lefer, Barry/B-5417-2012; Luke, Winston/D-1594-2016 OI Lefer, Barry/0000-0001-9520-5495; Luke, Winston/0000-0002-1993-2241 NR 26 TC 9 Z9 9 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1997 VL 102 IS D13 BP 16273 EP 16278 DI 10.1029/97JD00132 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XM347 UT WOS:A1997XM34700036 ER PT J AU Farahani, M Antonucci, JM Phinney, CS Karam, LR AF Farahani, M Antonucci, JM Phinney, CS Karam, LR TI Mass spectrometric analysis of polymers derived from N-aryl-alpha-amino acid initiators SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article ID DENTIN AB Previous studies have demonstrated that the interaction of carboxylic acids with aryl amines produces free radicals that can initiate the polymerization of acrylic monomers. N-Aryl-alpha-amino acids (NAAA) represent a special class of this type of initiator that combines in one molecule the carboxylic acid and aryl amine functionalities necessary for the generation of radical species. The mechanism(s) of radical formation in these molecules is thought to involve both electron transfer and hydrogen abstraction reactions that can occur by intra- and intermolecular pathways. Acrylic monomers, i.e., methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), were activated with various amounts of several NAAAs. Specific NAAAs investigated include N-phenylglycine (NPG) and N-p-tolylglycine (NTG). Polymerization was conducted at ambient or near ambient temperatures, and the polymers then were analyzed by electron impact mass spectrometry. Results indicate that these polymers have end groups derived directly from the NAAA initiators. (C) 1997 John Wiley & Sons, Inc. C1 NATL INST STAND & TECHNOL,DIV POLYMERS,GAITHERSBURG,MD 20809. NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20809. NATL INST STAND & TECHNOL,DEPT RADIAT PHYS,GAITHERSBURG,MD 20809. RP Farahani, M (reprint author), NIST,AMER DENT ASSOC HLTH FDN,PAFFENBARGER RES CTR,GAITHERSBURG,MD 20899, USA. NR 6 TC 9 Z9 9 U1 0 U2 4 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD JUL 18 PY 1997 VL 65 IS 3 BP 561 EP 565 DI 10.1002/(SICI)1097-4628(19970718)65:3<561::AID-APP16>3.0.CO;2-# PG 5 WC Polymer Science SC Polymer Science GA XG034 UT WOS:A1997XG03400016 ER PT J AU Easterling, DR Horton, B Jones, PD Peterson, TC Karl, TR Parker, DE Salinger, MJ Razuvayev, V Plummer, N Jamason, P Folland, CK AF Easterling, DR Horton, B Jones, PD Peterson, TC Karl, TR Parker, DE Salinger, MJ Razuvayev, V Plummer, N Jamason, P Folland, CK TI Maximum and minimum temperature trends for the globe SO SCIENCE LA English DT Article ID SURFACE AIR-TEMPERATURE; CLIMATE-CHANGE; UNITED-STATES; TIME-SERIES AB Analysis of the global mean surface air temperature has shown that its increase is due, at least in part, to differential changes in daily maximum and minimum temperatures, resulting in a narrowing of the diurnal temperature range (DTR). The analysis, using station metadata and improved areal coverage for much of the Southern Hemisphere landmass, indicates that the DTR is continuing to decrease in most parts of the world that urban effects on globally and hemispherically averaged time series are negligible, and that circulation variations in parts oi the Northern Hemisphere appear to be related to the DTR. Atmospheric aerosol loading in the Southern Hemisphere is much less than that in the Northern Hemisphere, suggesting that there are likely a number of factors, such as increases in cloudiness, contributing to the decreases in DTR. C1 METEOROL OFF, HADLEY CTR, BRACKNELL RB12 2SZ, BERKS, ENGLAND. UNIV E ANGLIA, CLIMAT RES UNIT, NORWICH NR4 7TJ, NORFOLK, ENGLAND. MATL INST WATER & ATMOSPHER RES, AUCKLAND, NEW ZEALAND. ALL RUSSIA RES INST HYDROMETEOROL INFORMAT, OBNINSK, RUSSIA. NATL CLIMATE CTR, BUR METEOROL, MELBOURNE, VIC, AUSTRALIA. DYNTEL INC, NATL CLIMAT DATA CTR, ASHEVILLE, NC 28801 USA. RP Easterling, DR (reprint author), NATL CLIMAT CTR, ASHEVILLE, NC 28801 USA. RI Jones, Philip/C-8718-2009; Folland, Chris/I-2524-2013 OI Jones, Philip/0000-0001-5032-5493; NR 22 TC 802 Z9 902 U1 8 U2 119 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 18 PY 1997 VL 277 IS 5324 BP 364 EP 367 DI 10.1126/science.277.5324.364 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XL358 UT WOS:A1997XL35800044 ER PT J AU Guyard, L Hapiot, P Neta, P AF Guyard, L Hapiot, P Neta, P TI Redox chemistry of bipyrroles: Further insights into the oxidative polymerization mechanism of pyrrole and oligopyrroles SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID LINEAR SWEEP VOLTAMMETRY; ELECTROCHEMICAL POLYMERIZATION; CATION RADICALS; ONE-ELECTRON; THIOPHENE OLIGOMERS; PHOTOCHEMICAL GENERATION; CYCLIC VOLTAMMETRY; AQUEOUS-SOLUTIONS; DEPROTONATION; ACETONITRILE AB The oxidation of 2,2'-bipyrrole, 5-methyl-2,2'-bipyrrole, and 5,5'-dimethyl-2,2'-bipyrrole has been investigated by means of electrochemistry, flash photolysis, and pulse radiolysis. The bipyrrole cation radical was found to give polypyrrole or oligopyrrole under electrochemical and chemical oxidation and also under UV-light irradiation of the solution in the presence of CCl4 as an electron acceptor, The cation radicals have been characterized by their optical absorption spectra, and their decay processes have been followed. In all processes (chemical, electrochemical, and photochemical), the first step involves the reaction between two cation radicals. The cation radical does not react on starting bipyrrole nor on pyrrole monomer, Depending on pH, the cation radical can deprotonate to form a neutral radical. It was found that only the cation radicals, but not the neutral radicals, produce higher oligomers, which explains the inhibition of polymerization by strong bases. C1 UNIV PARIS 07,ELECTROCHIM MOL LAB,CNRS,URA 438,F-75251 PARIS 05,FRANCE. UNIV FRANCHE COMTE,LAB CHIM & ELECTROCHIM MOL,F-25030 BESANCON,FRANCE. NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20889. NR 59 TC 84 Z9 84 U1 2 U2 19 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUL 17 PY 1997 VL 101 IS 29 BP 5698 EP 5706 DI 10.1021/jp9706083 PG 9 WC Chemistry, Physical SC Chemistry GA XM058 UT WOS:A1997XM05800013 ER PT J AU Abe, K Akagi, T Anderson, BD Anthony, PL Arnold, RG Averett, T Band, HR Berisso, CM Bogorad, P Borel, H Bosted, PE Breton, V Buenerd, MJ Cates, GD Chupp, TE Churchwell, S Coulter, KP Daoudi, M Decowski, P Erickson, R Fellbaum, JN Fonvieille, H Gearhart, R Ghazikhanian, V Griffioen, KA Hicks, RS Holmes, R Hughes, EW Igo, G Incerti, S Johnson, JR Kahl, W Khayat, M Kolomensky, YG Kuhn, SE Kumar, K Kuriki, M LombardNelsen, R Manley, DM Marroncle, J Maruyama, T Marvin, T Meyer, W Meziani, ZE Miller, D Mitchell, G Olson, M Peterson, GA Petratos, GG Pitthan, R Prepost, R Raines, P Raue, BA Reyna, D Rochester, LS Rock, SE Romalis, MV Sabatie, F Shapiro, G Shaw, J Smith, TB Sorrell, L Souder, PA Staley, F StLorant, S Stuart, LM Suekane, F Szalata, ZM Terrien, Y Thompson, AK Toole, T Wang, X Watson, JW Welsh, RC Wesselmann, FR Wright, T Young, CC Youngman, B Yuta, H Zhang, WM Zyla, P AF Abe, K Akagi, T Anderson, BD Anthony, PL Arnold, RG Averett, T Band, HR Berisso, CM Bogorad, P Borel, H Bosted, PE Breton, V Buenerd, MJ Cates, GD Chupp, TE Churchwell, S Coulter, KP Daoudi, M Decowski, P Erickson, R Fellbaum, JN Fonvieille, H Gearhart, R Ghazikhanian, V Griffioen, KA Hicks, RS Holmes, R Hughes, EW Igo, G Incerti, S Johnson, JR Kahl, W Khayat, M Kolomensky, YG Kuhn, SE Kumar, K Kuriki, M LombardNelsen, R Manley, DM Marroncle, J Maruyama, T Marvin, T Meyer, W Meziani, ZE Miller, D Mitchell, G Olson, M Peterson, GA Petratos, GG Pitthan, R Prepost, R Raines, P Raue, BA Reyna, D Rochester, LS Rock, SE Romalis, MV Sabatie, F Shapiro, G Shaw, J Smith, TB Sorrell, L Souder, PA Staley, F StLorant, S Stuart, LM Suekane, F Szalata, ZM Terrien, Y Thompson, AK Toole, T Wang, X Watson, JW Welsh, RC Wesselmann, FR Wright, T Young, CC Youngman, B Yuta, H Zhang, WM Zyla, P TI Next-to-leading order QCD analysis of polarized deep inelastic scattering data SO PHYSICS LETTERS B LA English DT Article ID SPIN STRUCTURE-FUNCTION; DEPENDENT PARTON DISTRIBUTIONS; STRUCTURE-FUNCTION G1(X); R=SIGMA-L/SIGMA-T; BJORKEN SUM-RULE; E-P; PRECISION-MEASUREMENT; ELECTRON-SCATTERING; PROTON; DEUTERON AB We present a next-to-leading order perturbative QCD analysis of world data on the spin dependent structure functions g(l)(p), g(l)(n), and g(l)(d), including the new experimental information on the Q(2) dependence of g(l)(n). Careful attention is paid to the experimental and theoretical uncertainties. The data constrain the first moments of the polarized valence quark distributions, but only qualitatively constrain the polarized sea quark and gluon distributions. The NLO results are used to determine the Q(2) dependence of the ratio g(l)/F-l and evolve the experimental data to a constant Q(2) = 5 GeV2. We determine the first moments of the polarized structure functions of the proton and neutron and find agreement with the Bjorken sum rule. (C) 1997 Published by Elsevier Science B.V. C1 UNIV CLERMONT FERRAND,LPC IN2P3,CNRS,F-63170 AUBIERE,FRANCE. UNIV CALIF BERKELEY,BERKELEY,CA 94720. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. CALTECH,PASADENA,CA 91125. CEA SACLAY,DAPNIA,SPHN,F-91191 GIF SUR YVETTE,FRANCE. KENT STATE UNIV,KENT,OH 44242. UNIV MASSACHUSETTS,AMHERST,MA 01003. UNIV MICHIGAN,ANN ARBOR,MI 48109. NIST,GAITHERSBURG,MD 20899. NORTHWESTERN UNIV,EVANSTON,IL 60201. OLD DOMINION UNIV,NORFOLK,VA 23529. UNIV PENN,PHILADELPHIA,PA 19104. PRINCETON UNIV,PRINCETON,NJ 08544. SMITH COLL,NORTHAMPTON,MA 01063. SO OREGON STATE COLL,ASHLAND,OR 97520. STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SYRACUSE UNIV,SYRACUSE,NY 13210. TEMPLE UNIV,PHILADELPHIA,PA 19122. TOHOKU UNIV,SENDAI,MIYAGI 980,JAPAN. COLL WILLIAM & MARY,WILLIAMSBURG,VA 23187. UNIV WISCONSIN,MADISON,WI 53706. INST NUCL SCI,IN2P3,CNRS,F-38026 GRENOBLE,FRANCE. RUHR UNIV BOCHUM,D-44780 BOCHUM,GERMANY. RP Abe, K (reprint author), AMERICAN UNIV,WASHINGTON,DC 20016, USA. RI Averett, Todd/A-2969-2011; Kolomensky, Yury/I-3510-2015; Sabatie, Franck/K-9066-2015; OI Kolomensky, Yury/0000-0001-8496-9975; Sabatie, Franck/0000-0001-7031-3975; Wesselmann, Frank/0000-0001-7834-7977; Kumar, Krishna/0000-0001-5318-4622; Incerti, Sebastien/0000-0002-0619-2053 NR 76 TC 127 Z9 127 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUL 17 PY 1997 VL 405 IS 1-2 BP 180 EP 190 DI 10.1016/S0370-2693(97)00641-2 PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XM606 UT WOS:A1997XM60600027 ER PT J AU Markley, TJ Toby, BH Pearlstein, RM Ramprasad, D AF Markley, TJ Toby, BH Pearlstein, RM Ramprasad, D TI New synthesis routes to lithium and cesium cyanide salts SO INORGANIC CHEMISTRY LA English DT Article AB New simple synthesis routes for two alkali cyanide salts, LiCN, and CsCN have been demonstrated. A crystal structure of LiCN . 0.6DMF . 0.4DMAc was obtained. The structure can be described as infinite sheets of Li pairs, linked end-on by cyanide ligands. The Li atoms are bridged above and below the sheet by a DMF or DMAc oxygen atom. C1 NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. RP Markley, TJ (reprint author), AIR PROD & CHEM INC,CORP SCI & TECHNOL CTR,7201 HAMILTON BLVD,ALLENTOWN,PA 18195, USA. RI Toby, Brian/F-3176-2013 OI Toby, Brian/0000-0001-8793-8285 NR 8 TC 17 Z9 17 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD JUL 16 PY 1997 VL 36 IS 15 BP 3376 EP & DI 10.1021/ic961395j PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA XL588 UT WOS:A1997XL58800025 ER PT J AU Wanninkhof, R Hitchcock, G Wiseman, WJ Vargo, G Ortner, PB Asher, W Ho, DT Schlosser, P Dickson, ML Masserini, R Fanning, K Zhang, JZ AF Wanninkhof, R Hitchcock, G Wiseman, WJ Vargo, G Ortner, PB Asher, W Ho, DT Schlosser, P Dickson, ML Masserini, R Fanning, K Zhang, JZ TI Gas exchange, dispersion, and biological productivity on the west Florida shelf: Results from a Lagrangian tracer study SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB A Lagrangian tracer study was performed on the west Florida shelf in April 1996 using deliberately injected trace gases. Although such studies have been performed previously, this work is the first where the deliberate tracers, in conjunction with carbon system parameters, are used to quantify changes in water column carbon inventories due to air-sea exchange and net community metabolism. The horizontal dispersion and the gas transfer velocity were determined over a period of 2 weeks from the change in both the concentrations and the concentration ratio of the two injected trace gases, sulfur hexafluoride (SF6) and helium-3 (He-3). The second moment of the patch grew to 1.6 x 10(3) km(2) over a period of 11 days. The gas transfer velocity, normalized to CO2 exchange at 20 degrees C, was 8.4 cm hr(-1) at an average wind speed, U-10, of 4.4 m s(-1) for the duration of the experiment, which is in good agreement with empirical estimates. Remineralization rates exceeded productivity, causing an increase in dissolved inorganic carbon of about 1 mu mol kg(-1) day(-1) in the water column. During this period of senescence, 80% of the increase in inorganic carbon is attributed to community remineralization and 20% due to invasion of atmospheric CO2. C1 UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,DEPT MARINE BIOL,MIAMI,FL 33149. LOUISIANA STATE UNIV,INST COASTAL STUDIES,BATON ROUGE,LA 70803. UNIV S FLORIDA,DEPT MARINE SCI,ST PETERSBURG,FL 33701. UNIV WASHINGTON,JISAU,SEATTLE,WA 98105. LAMONT DOHERTY EARTH OBSERV,PALISADES,NY 10964. COLUMBIA UNIV,DEPT EARTH & ENVIRONM SCI,PALISADES,NY 10964. UNIV RHODE ISL,GRAD SCH OCEANOG,NARRAGANSETT,RI 02882. RP Wanninkhof, R (reprint author), NOAA,ATLANTIC OCEANOG & METEOROL LAB,OCEAN CHEM DIV,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Zhang, Jia-Zhong/B-7708-2008; Ho, David/A-3154-2011; Schlosser, Peter/C-6416-2012 OI Zhang, Jia-Zhong/0000-0002-1138-2556; Ho, David/0000-0002-0944-6952; Schlosser, Peter/0000-0002-6514-4203 NR 14 TC 58 Z9 58 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1997 VL 24 IS 14 BP 1767 EP 1770 DI 10.1029/97GL01757 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XL837 UT WOS:A1997XL83700013 ER PT J AU Harrison, DE Larkin, NK AF Harrison, DE Larkin, NK TI Darwin sea level pressure, 1876-1996: Evidence for climate change? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOUTHERN OSCILLATION AB It has been argued that there was a period of prolonged ENSO conditions between 1990-95 so anomalous that it is ''highly unlikely'' to be due to ''natural decadal-timescale variation'' [Trenberth and Hear, 1996]. This conclusion follows from their study of the Darwin sea level pressure anomaly record, which found that the 1990-95 period would occur randomly about once every 1100-3000 yrs. Taking into account the uncertainty in number of degrees of freedom in the Darwin time series, we find that conditions like those of 1990-95 may be expected as often as every 150-200 yrs at the 95% confidence level. Student's-t, ARMA, and Bootstrap/Monte Carlo tests of the time series all yield similar results. We therefore suggest that the 1990-95 period may plausibly be an aspect of the natural variability of the tropical Pacific. C1 UNIV WASHINGTON,JOINT INST STUDY ATMOSPHERE & OCEANS,SEATTLE,WA 98195. RP Harrison, DE (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. RI Harrison, Don/D-9582-2013 NR 11 TC 36 Z9 36 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1997 VL 24 IS 14 BP 1779 EP 1782 DI 10.1029/97GL01789 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XL837 UT WOS:A1997XL83700016 ER PT J AU Korsgen, H Evenson, KM Brown, JM AF Korsgen, H Evenson, KM Brown, JM TI The bending vibration of FeD2 at 226 cm(-1), detected by far-infrared laser magnetic resonance spectroscopy SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BOND; FEH; SPECTRUM AB We report the first gas phase observation of a bending vibration in an open shell molecule by far-infrared laser magnetic resonance. The spectrum is due to FeD2; its observation shows that rovibrational transitions can be detected with such a spectrometer. The molecule was produced in the reaction between deuterium atoms and iron pentacarbonyl. FeD2 has a linear (5) Delta ground state and shows the effects of Renner-Teller coupling in the excited vibrational (010) level. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL, BOULDER, CO 80303 USA. PHYS & THEORET CHEM LAB, OXFORD OX1 3QZ, ENGLAND. NR 19 TC 11 Z9 11 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 15 PY 1997 VL 107 IS 3 BP 1025 EP 1027 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XK179 UT WOS:A1997XK17900038 ER PT J AU Hallberg, R AF Hallberg, R TI Stable split time stepping schemes for large-scale ocean modeling SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID SURFACE AB An explicit time integration of the primitive equations, which are often used for numerical ocean simulations, would be subject to a short time step limit imposed by the rapidly varying external gravity waves. One way to make this time step limit less onerous is to split the primitive equations into a simplified two-dimensional set of equations that describes the evolution of the external gravity waves and a much more slowly evolving three-dimensional remainder. The two-dimensional barotropic equations can be rapidly integrated over a large number of short time steps, while a much longer time step can be used with the much more complicated remainder. Unfortunately, it has recently been demonstrated that an inexact splitting into the fast and slow equations can lead to instability in the explicit integration of the slow equations. Here a more exact splitting of the equations is proposed. The proposed spl it time stepping scheme is demonstrated to be stable for linear inertia-gravity waves, subject to a time step limit based on the inertial frequency and internal gravity wave speeds. (C) 1997 Academic Press. C1 PRINCETON UNIV,NOAA,GFDL,PRINCETON,NJ 08542. RP Hallberg, R (reprint author), PRINCETON UNIV,PROGRAM ATMOSPHER & OCEAN SCI,FORRESTAL CAMPUS,US ROUTE 1,POB 308,PRINCETON,NJ 08542, USA. NR 9 TC 65 Z9 66 U1 1 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUL 15 PY 1997 VL 135 IS 1 BP 54 EP 65 DI 10.1006/jcph.1997.5734 PG 12 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA XL997 UT WOS:A1997XL99700004 ER PT J AU Ezer, T Mellor, GL AF Ezer, T Mellor, GL TI Simulations of the Atlantic Ocean with a free surface sigma coordinate ocean model SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID MERIDIONAL HEAT-FLUX; NORTH-ATLANTIC; THERMOHALINE CIRCULATION; GENERAL-CIRCULATION; GULF-STREAM; SEA-LEVEL; INTERPENTADAL VARIABILITY; ANNUAL CYCLE; TRANSPORT; RESOLUTION AB A sigma coordinate, free surface numerical model with turbulence dynamics has been implemented for the Atlantic Ocean and the Greenland Sea, from 80 degrees S to 80 degrees N. It is driven at the surface by monthly mean sea surface temperature and wind stress climatologies and is executed for 30 years. This is the first time that a model of this type, previously used mostly for coastal and regional simulations, has been implemented for the entire Atlantic Ocean and run for a long period of time. The model horizontal circulation, thermohaline overturning circulation, and meridional heat fluxes are described; the results are compared with observations and the results of other models. The model produces intense deep western boundary currents and complicated gyre structures associated with small-scale topographic variations. The meridional overturning circulation consists of about 14 Sv (1 Sv = 10(6) m(3) s(-1)) of southward flowing deep water mass crossing the equator and a northward heat flux with a maximum value of more than 1 PW (10(15) W). Although the maximum meridional heat flux is comparable to estimates obtained from observations, the amplitude of the seasonal variations of northward heat flux across 26 degrees N is underestimated in comparison with observations; it is similar to that obtained by other models. RP Ezer, T (reprint author), PRINCETON UNIV, PROGRAM ATMOSPHER & OCEAN SCI, POB CN710, SAYRE HALL, PRINCETON, NJ 08544 USA. OI Ezer, Tal/0000-0002-2018-6071 NR 60 TC 49 Z9 54 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1997 VL 102 IS C7 BP 15647 EP 15657 DI 10.1029/97JC00984 PG 11 WC Oceanography SC Oceanography GA XL452 UT WOS:A1997XL45200008 ER PT J AU Lee, K Millero, FJ Wanninkhof, R AF Lee, K Millero, FJ Wanninkhof, R TI The carbon dioxide system in the Atlantic Ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID DISSOCIATION-CONSTANTS; PH MEASUREMENTS; BORIC-ACID; SEA-WATER; SEAWATER; CO2; THERMODYNAMICS; CONSISTENCY; CALIBRATION; TEMPERATURE AB During the National Oceanic and Atmospheric Administration's Ocean Atmosphere Carbon Exchange Study expedition in the eastern North Atlantic in summer 1993, measurements of four CO2 parameters, along with hydrographic properties, were made: fugacity of CO2, fCO(2) (measured at 20 degrees C and in situ); pH (measured at 20 degrees C); total inorganic carbon, TCO2; and total alkalinity, TA. The major objective of this cruise was to establish a benchmark against which future measurements of the transient invasion of CO2 can be made. The large-scale distributions of surface water CO2 parameters were related to temperature and salinity in this region. The subsurface TA and TCO, measurements were fitted to multiple linear functions of salinity, in situ temperature, apparent oxygen utilization, and silicate. The measurements of the inorganic carbon system were also used to examine the internal consistency of the carbonate system in this area. The measurements were internally consistent to +/- 1,3 % in fCO(2), +/- 0.006 in pH, +/- 3 mu mol kg(-1) in TCO2, and +/- 3 mu mol kg(-1) in TA if proper carbonic acid dissociation constants are used for different input combinations. The thermodynamic constants of Goyet and Poisson [1989], Roy et al. [1993], Millero [1995], and Lee and Millero [1995] were most consistent with the measurements of pH (at 20 degrees C), TCO2, and TA. However, if fCO(2) (at 20 degrees C) is used in thermodynamic calculations, the constants of Mehrbach et al. [1973] gave the best representation of measurements. The constants of Lee and Millero [1995] were also reasonable agreement with these measurements. C1 NOAA,ATLANTIC OCEANOG & METEOROL LAB,DIV OCEAN CHEM,MIAMI,FL 33149. RP Lee, K (reprint author), UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,4600 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Lee, Kitack/G-7184-2015 NR 35 TC 46 Z9 51 U1 1 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1997 VL 102 IS C7 BP 15693 EP 15707 DI 10.1029/97JC00067 PG 15 WC Oceanography SC Oceanography GA XL452 UT WOS:A1997XL45200012 ER PT J AU Jung, YG Choi, SC Oh, CS Paik, UG AF Jung, YG Choi, SC Oh, CS Paik, UG TI Residual stress and thermal properties of zirconia/metal (nickel, stainless steel 304) functionally graded materials fabricated by hot pressing SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID TO-METAL JOINTS; GRADIENT MATERIALS; CERAMICS AB To analyse the residual stress and the thermal properties of functionally graded materials (FGMs), disc-type tetragonal zirconia polycrystal (TZP)/Ni- and TZP/stainless steel 304 (SUS304)-FGM were hot pressed, and compared with directly jointed materials (DJMs). The continuous interface and the microstructure of FGMs were characterized by electron probe microanalysis, wavelength dispersive spectrometry, optical microscopy and scanning electron microscopy. It has been verified that the defect-like cracks in FGMs are induced by the preferential shear stress and shown to cause fracture. These facts have corresponded well with the residual stress distribution analysed by the finite element method. The thermal diffusivity and the thermal conductivity of FGMs and DJMs were also measured by the laser flash technique. As a consequence, this work has described the interfacial stability, the residual stress release mechanism and the thermal protection characteristics of FGMs via a compositional gradient. C1 NIST,DIV CERAM,GAITHERSBURG,MD 20899. RP Jung, YG (reprint author), HANYANG UNIV,DEPT INORGAN MAT ENGN,SEOUL 133791,SOUTH KOREA. NR 34 TC 35 Z9 36 U1 3 U2 7 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD JUL 15 PY 1997 VL 32 IS 14 BP 3841 EP 3850 DI 10.1023/A:1018640126751 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA XM074 UT WOS:A1997XM07400030 ER PT J AU Montgomery, MT Lu, CG AF Montgomery, MT Lu, CG TI Free waves on barotropic vortices .1. Eigenmode structure SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RAPIDLY ROTATING VORTICES; SHALLOW-WATER; INSTABILITIES; BALANCE AB To understand the nature of coupling between a hurricane vortex and asymmetries in its near-core region, it is first necessary to have an understanding of the spectrum of free waves on barotropic vortices. As foundation for upcoming work examining the nonaxisymmetric initial-value problem in inviscid and swirling boundary layer vortex flows, the complete spectrum of free waves on barotropic vortices is examined here. For a variety of circular vortices in gradient balance the linearized momentum and continuity equations are solved as a matrix eigenvalue problem for perturbation height and wind fields. Vortex eigensolutions ale found to fall into two continuum classes. Eigenmodes with frequencies greater than the advective frequency for azimuthal wavenumber n are modified gravity-inertia waves possessing nonzero potential vorticity in the near-core region. Eigenmodes whose frequencies scale with the advective frequency comprise both gravity-inertia waves and Rossby-shear waves. Linearly superposing the Rossby-shear waves approximates the sheared disturbance solutions. For wavenumbers greater than a minimum number, Rossby-shear waves exhibit gravity wave characteristics in the near-vortex region. Although such eigenstructure changes are not anticipated by traditional scaling analyses using solely external how parameters, a criterion extending Rossby's characterization of ''balanced'' and ''unbalanced'' flow to that of azimuthal waves on a circular vortex is developed that correctly predicts the observed behavior from incipient vortices to hurricane-like vortices. The criterion is consistent with asymmetric balance theory. Possible applications of these results to the wave-mean-flow dynamics of geophysical vortex flows are briefly discussed. C1 NOAA,ERL,FORECAST SYST LAB,BOULDER,CO 80303. RP Montgomery, MT (reprint author), COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523, USA. NR 26 TC 36 Z9 39 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 15 PY 1997 VL 54 IS 14 BP 1868 EP 1885 DI 10.1175/1520-0469(1997)054<1868:FWOBVP>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XL168 UT WOS:A1997XL16800004 ER PT J AU Chen, J Jonsson, L Wilkins, JW Levine, ZH AF Chen, J Jonsson, L Wilkins, JW Levine, ZH TI Nonlinear local-field corrections to the optical second-harmonic susceptibility of insulating crystals SO PHYSICAL REVIEW B LA English DT Article ID 2ND-HARMONIC GENERATION; CUBIC SEMICONDUCTORS; DIELECTRIC-RESPONSE; SILICON; GAN; PSEUDOPOTENTIALS; FORMALISM; QUARTZ; ALN; BN AB There are two kinds of local-field corrections to the optical second-harmonic susceptibility in insulating crystals: those linear and those nonlinear In the macroscopic electric field originating from the linearly and nonlinearly induced microscopic charge densities, respectively. An algebraic relation is established between these two local-field corrections, which obviates the need to calculate the nonlinearly induced density. There is a hierarchy of local-field corrections consisting of first-, second-, and third-order corrections containing one, two, and three matrix elements of the linear local field, respectively. Our calculations show that the first-order local-field correction gives the leading correction. We demonstrate that the first-order correction from the previously neglected nonlinear local fields is exactly one half of the linear-local-field correction in the static limit. The newly computed total local-field corrections range from -21% to +30% for the 15 semiconductors and insulators studied. The expression recently obtained for the second-harmonic susceptibility using the (2n+1) theorem [A. Dal Corso et al., Phys. Rev. B 53, 15 638 (1996)] is shown to be equivalent to the expression we obtained using a sum-over-states method. C1 OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. NR 32 TC 32 Z9 32 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1997 VL 56 IS 4 BP 1787 EP 1799 DI 10.1103/PhysRevB.56.1787 PG 13 WC Physics, Condensed Matter SC Physics GA XY366 UT WOS:A1997XY36600025 ER PT J AU Mansky, P Russell, TP Hawker, CJ Mays, J Cook, DC Satija, SK AF Mansky, P Russell, TP Hawker, CJ Mays, J Cook, DC Satija, SK TI Interfacial segregation in disordered block copolymers: Effect of tunable surface potentials SO PHYSICAL REVIEW LETTERS LA English DT Article ID DIBLOCK COPOLYMERS; MIXTURES AB The response of disordered P(d-S-b-MMA) diblock copolymers to variable strength surface fields has been studied by neutron reflectivity. Surface interactions were controlled by end grafting P(S-r-MMA) random copolymers with various styrene contents onto Si substrates. segregation of the block copolymer was proportional to the surface potential. in the degree of segregation was observed as the brush composition was varied. Conditions were found which yielded neutral boundary conditions simultaneously at the vacuum and substrate interfaces. C1 IBM CORP,ALMADEN RES CTR,SAN JOSE,CA 95120. UNIV ALABAMA,DEPT CHEM,BIRMINGHAM,AL 35294. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Mansky, P (reprint author), UNIV MASSACHUSETTS,DEPT POLYMER SCI & ENGN,AMHERST,MA 01032, USA. RI Hawker, Craig/G-4971-2011 OI Hawker, Craig/0000-0001-9951-851X NR 26 TC 178 Z9 180 U1 5 U2 35 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 14 PY 1997 VL 79 IS 2 BP 237 EP 240 DI 10.1103/PhysRevLett.79.237 PG 4 WC Physics, Multidisciplinary SC Physics GA XK293 UT WOS:A1997XK29300015 ER PT J AU Herman, A Kumar, VB Arkin, PA Kousky, JV AF Herman, A Kumar, VB Arkin, PA Kousky, JV TI Objectively determined 10-day African rainfall estimates created for famine early warning systems SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID PRECIPITATION AB A method of estimation of accumulated precipitation which incorporates numerical model analyses, satellite and surface data has been developed for the African continent. An estimate for accumulated convective cloud precipitation is computed from cold cloud top temperature duration with a bias removal made from the use of rain-gauge data. Orographic precipitation from relatively warm cloud sources is estimated using a combination of surface and satellite data, orography, and numerical model analyses of relative humidity and wind. The results of a comparison of these precipitation estimates with independent rainfall data show this method produces skilful analyses of estimated accumulated precipitation for the Sahel region of Africa. C1 NATL CTR ENVIRONM PREDICT,CLIMATE PREDICT CTR,CAMP SPRINGS,MD 20746. RP Herman, A (reprint author), RES & DATA SYST CORP,GREENBELT,MD 20770, USA. RI Arkin, Phillip/F-5808-2010 NR 8 TC 113 Z9 116 U1 4 U2 11 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUL 10 PY 1997 VL 18 IS 10 BP 2147 EP 2159 DI 10.1080/014311697217800 PG 13 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA XH143 UT WOS:A1997XH14300006 ER PT J AU Wheat, CG Mottl, MJ Baker, ET Feely, RA Lupton, JE Sansone, FJ Resing, JA Lebon, G Becker, NC AF Wheat, CG Mottl, MJ Baker, ET Feely, RA Lupton, JE Sansone, FJ Resing, JA Lebon, G Becker, NC TI Chemical plumes from low-temperature hydrothermal venting on the eastern flank of the Juan de Fuca Ridge SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID MID-ATLANTIC RIDGE; WATER-COLUMN; PACIFIC RISE; DISSOLVED IRON; MARIANA MOUNDS; OCEANIC-CRUST; GUAYMAS BASIN; MANGANESE; SILICA; FLOW AB We report evidence for chemical anomalies in the water column from low-temperature ridge-flank hydrothermal venting. During cruises in 1992 and 1994, samples were taken from the water column for trace metals, nutrients, dissolved gases, and particles near each of three basaltic outcrops overlying 3.5 m. y. old crust on the eastern flank of the Juan de Fuca Ridge in Cascadia Basin. The water column above one of these outcrops, Baby Bare, which rises about 70 m above a flat turbidite plain, was the most thoroughly sampled. Thermal, chemical (Mn, Fe, delta(He-3)%, CH4, and O-2), and particulate anomalies in the water column confirm the existence of (1) early diagenesis of organic matter in seafloor sediment which produces a flux of dissolved metals and nutrients to bottom seawater, (2) hydrothermal emissions which are both focused (spring-like) and diffuse, and (3) resuspension of sediment by turbulent flow of tidal currents about a topographical high. On the basis of data from the water column and thermal and chemical pore water data from 46 piston and gravity sediment cores near and on Baby Bare (FlankFlux 90 and 92), we constrain the composition of seawater in basement and thus the composition of spring-like water. Given this composition, no measurable dissolved silica or phosphate hydrothermal anomalies are expected in the water column. C1 UNIV HAWAII, DEPT GEOL & GEOPHYS, HONOLULU, HI 96822 USA. OREGON STATE UNIV, HATFIELD MARINE SCI CTR, NOAA, PACIFIC MARINE ENVIRONM LAB, NEWPORT, OR 97365 USA. UNIV HAWAII, DEPT OCEANOG, HONOLULU, HI 96822 USA. RP Wheat, CG (reprint author), NOAA, PACIFIC MARINE ENVIRONM LAB, 7600 SAND POINT WAY NE, SEATTLE, WA 98115 USA. RI Sansone, Francis/B-9915-2013 NR 67 TC 22 Z9 22 U1 0 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JUL 10 PY 1997 VL 102 IS B7 BP 15433 EP 15446 DI 10.1029/96JB03890 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XJ831 UT WOS:A1997XJ83100045 ER PT J AU Abe, K Akagi, T Anderson, BD Anthony, PL Arnold, RG Averett, T Band, HR Berisso, CM Bogorad, P Borel, H Bosted, PE Breton, V Buenerd, MJ Cates, GD Chupp, TE Churchwell, S Coulter, KP Daoudi, M Decowski, P Erickson, R Fellbaum, JN Fonvieille, H Gearhart, R Ghazikhanian, V Griffioen, KA Hicks, RS Holmes, R Hughes, EW Igo, G Incerti, S Johnson, JR Kahl, W Khayat, M Kolomensky, YG Kuhn, SE Kumar, K Kuriki, M LombardNelsen, R Manley, DM Marroncle, J Maruyama, T Marvin, T Meyer, W Meziani, ZE Miller, D Mitchell, G Olson, M Peterson, GA Petratos, GG Pitthan, R Prepost, R Raines, P Raue, BA Reyna, D Rochester, LS Rock, SE Romalis, MV Sabatie, F Shapiro, G Shaw, J Smith, TB Sorrell, L Souder, PA Staley, F StLorant, S Stuart, LM Suekane, F Szalata, ZM Terrien, Y Thompson, AK Toole, T Wang, X Watson, JW Welsh, RC Wesselmann, FR Wright, T Young, CC Youngman, B Yuta, H Zhang, WM Zyla, P AF Abe, K Akagi, T Anderson, BD Anthony, PL Arnold, RG Averett, T Band, HR Berisso, CM Bogorad, P Borel, H Bosted, PE Breton, V Buenerd, MJ Cates, GD Chupp, TE Churchwell, S Coulter, KP Daoudi, M Decowski, P Erickson, R Fellbaum, JN Fonvieille, H Gearhart, R Ghazikhanian, V Griffioen, KA Hicks, RS Holmes, R Hughes, EW Igo, G Incerti, S Johnson, JR Kahl, W Khayat, M Kolomensky, YG Kuhn, SE Kumar, K Kuriki, M LombardNelsen, R Manley, DM Marroncle, J Maruyama, T Marvin, T Meyer, W Meziani, ZE Miller, D Mitchell, G Olson, M Peterson, GA Petratos, GG Pitthan, R Prepost, R Raines, P Raue, BA Reyna, D Rochester, LS Rock, SE Romalis, MV Sabatie, F Shapiro, G Shaw, J Smith, TB Sorrell, L Souder, PA Staley, F StLorant, S Stuart, LM Suekane, F Szalata, ZM Terrien, Y Thompson, AK Toole, T Wang, X Watson, JW Welsh, RC Wesselmann, FR Wright, T Young, CC Youngman, B Yuta, H Zhang, WM Zyla, P TI Measurement of the neutron spin structure function g(2)(n) and asymmetry A(2)(n) SO PHYSICS LETTERS B LA English DT Article ID DEEP-INELASTIC-SCATTERING; STRUCTURE-FUNCTION G1(X); SUM-RULE; PRECISION-MEASUREMENT; POLARIZED NUCLEONS; POWER CORRECTIONS; PROTON; DEUTERON; LEPTONS; TARGET AB We have measured the neutron structure function g(2)(n) and the virtual photon-nucleon asymmetry A(2)(n) over the kinematic range 0.014 less than or equal to x less than or equal to 0.7 and 1.0 less than or equal to Q(2) less than or equal to 17.0 by scattering 48.3 GeV longitudinally polarized electrons from polarized He-3. Results for A(2)(n) are significantly smaller than the root R positivity limit over most of the measured range and data for g(2)(n), are generally consistent with the twist-2 Wandzura-Wilczek prediction. Using our measured g(2)(n) we obtain results for the twist-3 reduced matrix element d(2)(n), and the integral integral g(2)(n)(x) dx in the range 0.014 less than or equal to x less than or equal to 1.0. Data from this experiment are combined with existing data for g(2)(n) to obtain an average for d(2)(n) and the integral integral g(2)(n)(x) dx. (C) 1997 Published by Elsevier Science B.V. C1 AMERICAN UNIV, WASHINGTON, DC 20016 USA. UNIV CLERMONT FERRAND, LPC, CNRS, IN2P3, F-63170 AUBIERE, FRANCE. UNIV CALIF BERKELEY, BERKELEY, CA 94720 USA. UNIV CALIF LOS ANGELES, LOS ANGELES, CA 90024 USA. CALTECH, PASADENA, CA 91125 USA. CTR ETUD SACLAY, SPHN, DAPNIA, F-91191 GIF SUR YVETTE, FRANCE. KENT STATE UNIV, KENT, OH 44242 USA. UNIV MASSACHUSETTS, AMHERST, MA 01003 USA. UNIV MICHIGAN, ANN ARBOR, MI 48109 USA. NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NORTHWESTERN UNIV, EVANSTON, IL 60201 USA. OLD DOMINION UNIV, NORFOLK, VA 23529 USA. UNIV PENN, PHILADELPHIA, PA 19104 USA. PRINCETON UNIV, PRINCETON, NJ 08544 USA. SMITH COLL, NORTHAMPTON, MA 01063 USA. SO OREGON STATE COLL, ASHLAND, OR 97520 USA. STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94309 USA. SYRACUSE UNIV, SYRACUSE, NY 13210 USA. TEMPLE UNIV, PHILADELPHIA, PA 19122 USA. COLL WILLIAM & MARY, WILLIAMSBURG, VA 23187 USA. UNIV WISCONSIN, MADISON, WI 53706 USA. CNRS, INST NUCL SCI, IN2P3, F-38026 GRENOBLE, FRANCE. RUHR UNIV BOCHUM, D-44780 BOCHUM, GERMANY. RP Abe, K (reprint author), TOHOKU UNIV, SENDAI, MIYAGI 980, JAPAN. RI Averett, Todd/A-2969-2011; Kolomensky, Yury/I-3510-2015; Sabatie, Franck/K-9066-2015 OI Kolomensky, Yury/0000-0001-8496-9975; Sabatie, Franck/0000-0001-7031-3975 NR 32 TC 66 Z9 66 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUL 10 PY 1997 VL 404 IS 3-4 BP 377 EP 382 DI 10.1016/S0370-2693(97)00613-8 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA XK526 UT WOS:A1997XK52600023 ER PT J AU Wladkowski, BD Chenoweth, SA Sanders, JN Krauss, M Stevens, WJ AF Wladkowski, BD Chenoweth, SA Sanders, JN Krauss, M Stevens, WJ TI Acylation of beta-lactams by class A beta-lactamase: An ab initio theoretical study on the effects of the oxy-anion hole SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SITE-DIRECTED MUTAGENESIS; ACYL-ENZYME INTERMEDIATE; STAPHYLOCOCCUS-AUREUS PC1; BACILLUS-LICHENIFORMIS 749/C; CRYSTAL-STRUCTURE; PENICILLIN RECEPTOR; ESCHERICHIA-COLI; SUBSTRATE-BINDING; RIBONUCLEASE-A; RESOLUTION AB The initial acylation step in the beta-lactamase catalyzed hydrolysis of beta-lactams is studied using an ab initio quantum mechanical approach. The computational model incorporates a simple beta-lactam substrate and key residues found in the active site in order to assess the plausibility of a specific mechanism originally proposed by Strynadka et al.(1) and to estimate the stabilizing effects of the oxy-anion hole components founds in these enzymes. The computational model was constructed using information obtained from a high resolution X-ray crystal structure of unbound native beta-lactamase, isolated from Staphylococcus aureus PC1. Within this model, the overall acylation reaction was found to occur with modest activation energy <26 kcal mol(-1) (<109 kT mol(-1)) through a microscopic pathway characterized by discrete proton transfer steps between the substrate and the active site residues Ser-70, Lys-73, and Ser-130. These energetic results are considerably lower than the activation energies found for the uncatalyzed hydrolysis of simple amides in the gas phase. Interestingly, the energetic stabilization of the components, which make up the oxy-anion hole, were found to be modest with only one stationary point on the potential energy surface being significantly reduced by similar to 8 kcal mol(-1) (similar to 33 kJ mol(-1)). C1 NIST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. RP Wladkowski, BD (reprint author), WESTERN MARYLAND COLL,DEPT CHEM,2 COLL HILL,WESTMINSTER,MD 21157, USA. NR 58 TC 40 Z9 40 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUL 9 PY 1997 VL 119 IS 27 BP 6423 EP 6431 DI 10.1021/ja963678g PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA XJ833 UT WOS:A1997XJ83300024 ER PT J AU Bluhm, H Wadas, A Wiesendanger, R Roshko, A Aust, JA Nam, D AF Bluhm, H Wadas, A Wiesendanger, R Roshko, A Aust, JA Nam, D TI Imaging of domain-inverted gratings in LiNbO3 by electrostatic force microscopy SO APPLIED PHYSICS LETTERS LA English DT Article ID SURFACE; WALLS AB Ferroelectric domains in LiNbO3, have been investigated by means of electrostatic force microscopy. Polarization-inverted gratings with 4 mu m periodicity were fabricated by titanium diffusion into both +c and -c faces of single-domain LiNbO3 crystals. The distribution of the electric field in the vicinity of the sample surface was measured using scanning probe microscopy. The electrostatic force image was found to correlate with the shape of the domain-inverted profile observed by scanning electron and optical microscopies. (C) 1997 American Institute of Physics. C1 UNIV HAMBURG, INST PHYS APPL, D-20355 HAMBURG, GERMANY. UNIV HAMBURG, MICROSTRUCT RES CTR, D-20355 HAMBURG, GERMANY. NATL INST STAND & TECHNOL, BOULDER, CO 80303 USA. SPECTRA DIODE LABS, SAN JOSE, CA 95134 USA. RI Wiesendanger, Roland/P-9726-2016 OI Wiesendanger, Roland/0000-0002-0472-4183 NR 12 TC 29 Z9 29 U1 0 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 7 PY 1997 VL 71 IS 1 BP 146 EP 148 DI 10.1063/1.119455 PG 3 WC Physics, Applied SC Physics GA XJ139 UT WOS:A1997XJ13900050 ER PT J AU Abe, K Akagi, T Anderson, BD Anthony, PL Arnold, RG Averett, T Band, HR Berisso, CM Bogorad, P Borel, H Bosted, PE Breton, V Buenerd, MJ Cates, GD Chupp, TE Churchwell, S Coulter, KP Daoudi, M Decowski, P Erickson, R Fellbaum, JN Fonvieille, H Gearhart, R Ghazikhanian, V Griffioen, KA Hicks, RS Holmes, R Hughes, EW Igo, G Incerti, S Johnson, JR Kahl, W Khayat, M Kolomensky, YG Kuhn, SE Kumar, K Kuriki, M LombardNelsen, R Manley, DM Marroncle, J Maruyama, T Marvin, T Meyer, W Meziani, ZE Miller, D Mitchell, G Olson, M Peterson, GA Petratos, GG Pitthan, R Prepost, R Raines, P Raue, B Reyna, D Rochester, LS Rock, SE Romalis, MV Sabatie, F Shapiro, G Shaw, J Smith, TB Sorrell, L Souder, PA Staley, F StLorant, S Stuart, LM Suekane, F Szalata, ZM Terrien, Y Thompson, AK Toole, T Wang, X Watson, JW Welsh, RC Wesselmann, F Wright, T Young, CC Youngman, B Yuta, H Zhang, WM Zyla, P AF Abe, K Akagi, T Anderson, BD Anthony, PL Arnold, RG Averett, T Band, HR Berisso, CM Bogorad, P Borel, H Bosted, PE Breton, V Buenerd, MJ Cates, GD Chupp, TE Churchwell, S Coulter, KP Daoudi, M Decowski, P Erickson, R Fellbaum, JN Fonvieille, H Gearhart, R Ghazikhanian, V Griffioen, KA Hicks, RS Holmes, R Hughes, EW Igo, G Incerti, S Johnson, JR Kahl, W Khayat, M Kolomensky, YG Kuhn, SE Kumar, K Kuriki, M LombardNelsen, R Manley, DM Marroncle, J Maruyama, T Marvin, T Meyer, W Meziani, ZE Miller, D Mitchell, G Olson, M Peterson, GA Petratos, GG Pitthan, R Prepost, R Raines, P Raue, B Reyna, D Rochester, LS Rock, SE Romalis, MV Sabatie, F Shapiro, G Shaw, J Smith, TB Sorrell, L Souder, PA Staley, F StLorant, S Stuart, LM Suekane, F Szalata, ZM Terrien, Y Thompson, AK Toole, T Wang, X Watson, JW Welsh, RC Wesselmann, F Wright, T Young, CC Youngman, B Yuta, H Zhang, WM Zyla, P TI Precision determination of the neutron spin structure function g(1)(n) SO PHYSICAL REVIEW LETTERS LA English DT Article ID DEEP-INELASTIC-SCATTERING; DEPENDENT FREQUENCY-SHIFTS; POLARIZED PROTONS; RB-HE-3 COLLISIONS; HE-3 TARGETS; HIGH-DENSITY; DEUTERON; LEPTONS; ELECTRONS; NUCLEONS AB We report on a precision measurement of the neutron spin structure function g(l)(n) using deep inelastic scattering of polarized electrons by polarized He-3. For the kinematic range 0.014 < x < 0.7 and 1 < Q(2) < 17 (GeV/c)(2), we obtain integral(0.014)(0.7) g(l)(n)(x)dx = -0.036 +/- 0.004(stat) +/- 0.005(syst) at an average Q(2) = 5 (GeV/c)(2). We find relatively large negative values for g(l)(n) at low x. The results call into question the usual Regge theory method for extrapolating to x = 0 to find the full neutron integral integral(0)(1) g(l)(n)(x)dx, needed for testing the quark-parton model and QCD sum rules. C1 AMERICAN UNIV, WASHINGTON, DC 20016 USA. UNIV CALIF BERKELEY, BERKELEY, CA 94720 USA. UNIV CLERMONT FERRAND, LPC, IN2P3, CNRS, F-63170 AUBIERE, FRANCE. UNIV BONN, D-5300 BONN, GERMANY. CALTECH, PASADENA, CA 91125 USA. DAPNIA, F-91191 GIF SUR YVETTE, FRANCE. KENT STATE UNIV, KENT, OH 44242 USA. UNIV CALIF LOS ANGELES, LOS ANGELES, CA 90024 USA. UNIV MASSACHUSETTS, AMHERST, MA 01003 USA. UNIV MICHIGAN, ANN ARBOR, MI 48109 USA. NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NORTHWESTERN UNIV, EVANSTON, IL 60201 USA. OLD DOMINION UNIV, NORFOLK, VA 23529 USA. UNIV PENN, PHILADELPHIA, PA 19104 USA. PRINCETON UNIV, PRINCETON, NJ 08544 USA. SO OREGON STATE COLL, ASHLAND, OR 97520 USA. SMITH COLL, NORTHAMPTON, MA 01063 USA. STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94309 USA. SYRACUSE UNIV, SYRACUSE, NY 13210 USA. TEMPLE UNIV, PHILADELPHIA, PA 19122 USA. COLL WILLIAM & MARY, WILLIAMSBURG, VA 23187 USA. UNIV WISCONSIN, MADISON, WI 53706 USA. RP Abe, K (reprint author), TOHOKU UNIV, ARAMAKI AZA AOBA, SENDAI, MIYAGI 980, JAPAN. RI Averett, Todd/A-2969-2011; Kolomensky, Yury/I-3510-2015; Sabatie, Franck/K-9066-2015; OI Kolomensky, Yury/0000-0001-8496-9975; Sabatie, Franck/0000-0001-7031-3975; Wesselmann, Frank/0000-0001-7834-7977; Incerti, Sebastien/0000-0002-0619-2053 NR 46 TC 330 Z9 330 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 7 PY 1997 VL 79 IS 1 BP 26 EP 30 DI 10.1103/PhysRevLett.79.26 PG 5 WC Physics, Multidisciplinary SC Physics GA XH870 UT WOS:A1997XH87000007 ER PT J AU Fahr, A Laufer, AH Krauss, M Osman, R AF Fahr, A Laufer, AH Krauss, M Osman, R TI Gas phase absorption spectrum and cross sections of vinylperoxy (C2H3O2) radical SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PEROXYL RADICALS; ULTRAVIOLET-ABSORPTION; ELECTRONIC-STRUCTURE; LASER PHOTOLYSIS; VINYL RADICALS; RATE-CONSTANT; KINETICS; OXYGEN; STATES; METHYL AB The absorption spectrum and cross sections of vinylperoxy (C2H3O2, ethenylperoxy) radical have been determined, for the first time in the gas phase, in the spectral range 220-550 nm. The spectrum exhibits a relatively broad and intense absorption centered at about 232 nm, followed by at least two identifiable and weaker absorptions with maxima at about 340 and 420 nm. The absorption tail persists at longer wavelengths into the visible region, To discern competition between the stabilization of the vinylperoxy isomers and reaction, the effect of pressure on the absorption has been examined, Vinylperoxy radicals in these experiments were produced through photochemical production of vinyl radicals followed by reaction of vinyl radicals with molecular oxygen. Vinyl bromide (C2H3Br) photolyzed at 193 nm was used as the precursor of vinyl radicals, and methyl vinyl ketone (CH3COC2H3) photolyzed at 193 nm was used as a precursor of both methyl and vinyl radicals. In the latter system identical concentrations of methyl and vinyl peroxy radicals were produced, and by employing comparative methods and using the literature values for methylperoxy absorption cross sections, the absolute absorption cross sections for vinylperoxy were determined. Ab initio molecular orbital calculations of CH3O2, C2H3O2. C2H3O, and HCO have been employed to characterize the observed spectrum and to identify the species and assign transitions contributing to the spectrum, These calculations suggest that the observed spectrum can primarily be assigned to two stable isomers (conformations) of the vinylperoxy radical with the O-O bond in a cis or trans position relative to the C-C bond, with a minor contribution to the absorption spectrum from the vinery and formyl radicals. For unsaturated radicals and the weak bonds involved here, accurate geometries are difficult to calculate, but the geometry obtained by gradient optimization using the multiconfiguration self-consistent-field method yields excitation energies that most closely agree with experiment. The relative theoretical oscillator strengths of all relevant vinylperoxy and vinery transitions have been evaluated and assist the analysis of the pressure dependence of the absorption spectrum. C1 NIST,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. CUNY MT SINAI SCH MED,DEPT PHYSIOL & BIOPHYS,NEW YORK,NY 10029. RP Fahr, A (reprint author), NIST,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899, USA. NR 38 TC 10 Z9 10 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 3 PY 1997 VL 101 IS 27 BP 4879 EP 4886 DI 10.1021/jp964005n PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XJ439 UT WOS:A1997XJ43900009 ER PT J AU Lovejoy, ER AF Lovejoy, ER TI Kinetics and thermodynamics of the gas phase reaction SO3+NH3+N-2<->H3NSO3+N-2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID RATE-CONSTANT; ACID AB The kinetics of the gas phase reaction SO3 + NH3 + N-2 reversible arrow H3NSO3 + N-2 were studied with a flow reactor coupled to a chemical ionization mass spectrometer for detection of SO3 and H3NSO3. The rate coefficient for the association reaction SO3 + NH3 + N-2 was measured as a function of temperature (280-340 K) and pressure (20-80 Torr of N-2). Analysis of the SO3 decay and H3NSO3 appearance at higher temperatures yielded rate coefficients for H3NSO3 decomposition and the enthalpy of the reaction SO3 + NH3 reversible arrow H3NSO3: Delta H(298K)degrees = -24 +/- 1 kcal mol(-1). RP Lovejoy, ER (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 15 TC 4 Z9 4 U1 2 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 3 PY 1997 VL 101 IS 27 BP 4950 EP 4953 DI 10.1021/jp970652i PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XJ439 UT WOS:A1997XJ43900019 ER PT J AU Burns, TJ Davis, RW Moore, EF AF Burns, TJ Davis, RW Moore, EF TI Dynamical systems approach to particle transport modeling in dilute gas-particle transport modeling in dilute gas-particle flows with application to a chemical vapor deposition reactor (vol 26, pg 193, 1997) SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Correction, Addition AB A general method for treating the transport of particles in dilute gas-particle hows is presented. This method formulates the particle transport equations as a dynamical system, and utilizes the corresponding theory to analyze the resulting dynamics. As an illustration of this technique, the transport of contaminant particles in a barrel-type CVD reactor is analyzed. The background gas how field is determined via a numerical simulation of the Navier-Stokes equations. The analysis reveals the presence of particle attractors in the flow which are particle size specific. The features of these attractors are discussed, as is their behavior with varying particle size. (C) 1997 American Association for Aerosol Research. C1 NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. RP Burns, TJ (reprint author), NIST,COMP & APPL MATH LAB,GAITHERSBURG,MD 20899, USA. NR 32 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD JUL PY 1997 VL 27 IS 1 BP R4 EP & PG 22 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XF497 UT WOS:A1997XF49700001 ER PT J AU Bunk, DH AF Bunk, DH TI Characterization of the glycation of albumin in freeze dried and frozen human serum SO ANALYTICAL CHEMISTRY LA English DT Article ID LIQUID-CHROMATOGRAPHY; ALKALINE-PHOSPHATASE; MASS-SPECTROMETRY; IDENTIFICATION; GLYCOSYLATION; INVIVO AB Human serum albumin (HSA) in fresh frozen and freeze-dried serum reference materials was examined by mass spectrometry and a variety of affinity chromatography techniques. The relative molecular mass distribution of HSA in fresh frozen serum was found to be identical to that of an HSA standard. However, the HSA in the freeze-dried reference serum exhibited a relative molecular mass distribution that was shifted to higher mass, broader, and substantially more heterogeneous than that of HSA in fresh frozen serum, A proteolytic cyanogen bromide digestion of the HSA from freeze-dried serum contained adducts similar to 162 u higher in mass than digest fragments 124-298 and 447-548, suggesting glycation. The presence of glycation on fragments 124-298 and 447-548 correlates with the known sites of HSA glycation. Glycation was further confirmed by the mass spectral analysis of the retained and unretained fractions from glycoaffinity chromatography of HSA from freeze-dried serum. The relative molecular weight of the HSA in the retained fraction indicated the presence of a doubly glycated species, The chemical heterogeneity of Cys-34, the site of the only free thiol in HSA, was examined and found not to be a substantial source of molecular mass heterogeneity for HSA from either fresh frozen or freeze-dried serum. RP Bunk, DH (reprint author), NIST,BLDG 222-B208,GAITHERSBURG,MD 20899, USA. NR 22 TC 18 Z9 19 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 1 PY 1997 VL 69 IS 13 BP 2457 EP 2463 DI 10.1021/ac961205m PG 7 WC Chemistry, Analytical SC Chemistry GA XG497 UT WOS:A1997XG49700041 PM 9212708 ER PT J AU Graczyk, TK Balazs, GH Work, T Aguirre, AA Ellis, DM Murakawa, SKK Morris, R AF Graczyk, TK Balazs, GH Work, T Aguirre, AA Ellis, DM Murakawa, SKK Morris, R TI Cryptosporidium sp. infections in green turtles, Chelonia mydas, as a potential source of marine waterborne oocysts in the Hawaiian Islands SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID PARVUM OOCYSTS; WILD AB For the first time, Cryptosporidium sp. oocysts were identified in fecal and intestinal samples from free-ranging marine turtles, Chelonia mydas, from the Hawaiian Islands. The oocysts produced positive reactions with commercial test kits recommended for the detection of human-infectious waterborne oocysts of Cryptosporidium parvum. C1 NATL MARINE FISHERIES SERV,HONOLULU LAB,SW FISHERIES SCI CTR,HONOLULU,HI 96822. JOINT INST MARINE & ATMOSPHER RES,HONOLULU,HI 96822. NATL WILDLIFE HLTH RES CTR,HONOLULU FIELD STN,HONOLULU,HI 96850. MAKAI ANIM CLIN,KAILUA,HI 96734. RP Graczyk, TK (reprint author), JOHNS HOPKINS UNIV,SCH HYG & PUBL HLTH,DEPT MOL MICROBIOL & IMMUNOL,615 N WOLFE ST,BALTIMORE,MD 21205, USA. RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 NR 21 TC 12 Z9 15 U1 0 U2 7 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD JUL PY 1997 VL 63 IS 7 BP 2925 EP 2927 PG 3 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA XJ182 UT WOS:A1997XJ18200065 PM 16535658 ER PT J AU Cole, KD Lee, TK Lubon, H AF Cole, KD Lee, TK Lubon, H TI Aqueous two-phase partitioning of milk proteins - Application to human protein C secreted in pig milk SO APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY LA English DT Article DE protein C; expression; recombinant animal; milk; aqueous two-phase extraction; purification ID 2-PHASE SYSTEMS; POLYETHYLENE-GLYCOL; POLYSACCHARIDE SYSTEMS; POLYACRYLAMIDE GELS; BETA-LACTOGLOBULIN; ALPHA-LACTALBUMIN; BOVINE WHEY; SEPARATION; EXTRACTION; ELECTROPHORESIS AB Milk of transgenic pigs secreting recombinant human Protein C (rHPC) was used as a model system to determine the utility of aqueous two-phase extraction systems (ATPS) for the initial step in the purification of proteins from milk. The major challenges in purification of recombinant proteins from milk are removal of casein micelles (that foul processing equipment) and elimination of the host milk proteins from the final product. When milk was partitioned in ATPS composed of polyethylene glycol (PEG) and ammonium sulfate (AS), the phases were clarified and most of the caseins precipitated at the interphase. The partition coefficients of the major milk proteins and rHPC were dependent upon the molecular weight of the PEG used in the ATPS. Higher-partition coefficients of the major whey proteins, beta-lactoglobulin, and a-lactalbumin were observed in ATPS made up of lower molecular-weight PEG (1000 or 1450) as compared to systems using higher molecular-weight PEG. Lowering the pH of the ATPS from 7.5 to 6.0 resulted in increased precipitation of the caseins and decreased their concentration in both phases. rHPC had a partition coefficient of 0.04 in a system composed of AS and PEG 1450. The rHPC in pig milk was shown to be highly heterogenous by hive-dimensional gel electrophoresis. The heterogeneity was owing to inefficient proteolytic processing of the single chain to the heterodimeric form and differences in glycosylation and other post-translational processing. Differential partitioning of the multiple forms of purified rHPC in the ATPS was not observed. rHPC after processing in ATPS was recovered in a clear phase free of most major milk proteins. ATPS are useful as the initial processing step in the purification of recombinant proteins from milk because clarification and enrichment is combined in a single step. C1 AMER RED CROSS,JEROME H HOLLAND LAB,PLASMA DERIVAT LAB,ROCKVILLE,MD 20855. RP Cole, KD (reprint author), NATL INST STAND & TECHNOL,DIV BIOTECHNOL,GAITHERSBURG,MD 20899, USA. NR 25 TC 1 Z9 2 U1 0 U2 0 PU HUMANA PRESS INC PI TOTOWA PA 999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 SN 0273-2289 J9 APPL BIOCHEM BIOTECH JI Appl. Biochem. Biotechnol. PD JUL-AUG PY 1997 VL 67 IS 1-2 BP 97 EP 112 DI 10.1007/BF02787845 PG 16 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA XY762 UT WOS:A1997XY76200009 PM 9382491 ER PT J AU Booth, JC Beall, JA Ono, RH Stork, FJB Rudman, DA Vale, LR AF Booth, JC Beall, JA Ono, RH Stork, FJB Rudman, DA Vale, LR TI Third-order harmonic generation in high-temperature superconducting coplanar waveguides at microwave frequencies SO APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 6th International Superconductive Electronics Conference (ISEC 97) CY JUN 25-28, 1997 CL BERLIN, GERMANY SP Phys Tech Bundesanstalt, German Natl Inst Metrol ID IMPLANTATION AB We use third-harmonic measurements of coplanar waveguide (CPW) transmission lines to explore the behavior of nonlinearities in microwave devices fabricated from high-T-c superconductors. Our measurements focus on the effect of varying the CPW geometry, including center conductor linewidth, line length, and film thickness, on the nonlinearity of the transmission line circuit as measured by the third-order intercept. The third-order intercepts decrease (indicating more nonlinearity) with increasing line length for all geometries studied. Also, differences in the third-order intercepts between lines of different linewidth and film thickness can be explained quantitatively by appropriately scaling the incident microwave power. These observations demonstrate that the sources of nonlinearity in our CPW transmission lines are distributed along the line length, and depend on the detailed form of the current distribution within the superconductor. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Booth, JC (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0964-1807 J9 APPL SUPERCOND JI Appl. Supercond. PD JUL-DEC PY 1997 VL 5 IS 7-12 BP 379 EP 384 DI 10.1016/S0964-1807(98)00056-8 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 116UN UT WOS:000075743500027 ER PT J AU Huber, ME Corey, AM Lumpkins, KL Nafe, FN Rantschler, JO Hilton, GC Martinis, JM Steinbach, AH AF Huber, ME Corey, AM Lumpkins, KL Nafe, FN Rantschler, JO Hilton, GC Martinis, JM Steinbach, AH TI DC SQUID series arrays with intracoil damping to reduce resonance distortions SO APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 6th International Superconductive Electronics Conference (ISEC 97) CY JUN 25-28, 1997 CL BERLIN, GERMANY SP Phys Tech Bundesanstalt, German Natl Inst Metrol ID INPUT COIL; NOISE AB We report on low-noise DC SQUID series arrays incorporating intracoil damping, which show smooth DC characteristics. The voltage-flux characteristics of these devices are reproducible upon repeated cooling and do not require multiple heating/cooling cycles to maximize peak-to-peak output voltage modulation depth. The devices consist of 100 DC SQUIDs with individual signal and feedback coils connected in series. The total input inductance is 600 nH, and the peak-to-peak output modulation is 4 mV with a transfer function of 350 V/A. The bandwidth is 5 MHz and the equivalent input current noise is approximately 2.5 pA/root Hz. With these characteristics, these devices are useful as preamplifiers for microcalorimeter X-ray detectors. Published by Elsevier Science Ltd. C1 Univ Colorado, Dept Phys, Denver, CO 80217 USA. Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RP Huber, ME (reprint author), Univ Colorado, Dept Phys, POB 173364, Denver, CO 80217 USA. RI Huber, Martin/B-3354-2011 NR 14 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0964-1807 J9 APPL SUPERCOND JI Appl. Supercond. PD JUL-DEC PY 1997 VL 5 IS 7-12 BP 425 EP 429 DI 10.1016/S0964-1807(98)00065-9 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 116UN UT WOS:000075743500034 ER PT J AU Vong, RJ Baker, BM Brechtel, FJ Collier, RT Harris, JM Kowalski, AS McDonald, NC McInnes, LM AF Vong, RJ Baker, BM Brechtel, FJ Collier, RT Harris, JM Kowalski, AS McDonald, NC McInnes, LM TI Ionic and trace element composition of cloud water collected on the Olympic Peninsula of Washington State SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE acid rain; size-dependent composition; organic acids; PLS regression ID CHEMICAL-COMPOSITION; PRECIPITATION CHEMISTRY; FLOW PATTERNS; DROP SIZE; FOG; SULFATE; DEPOSITION; DEPENDENCE; AEROSOL; IDENTIFICATION AB Field measurements of the chemical composition of boundary-layer clouds that formed in clean, marine air are presented as a background reference point for comparison to cloud water composition in more polluted regions. An impaction-based sampler was used to simultaneously collect cloud water on two stages, where the ratio of droplet diameter was similar to 1.1 for the two droplet size fractions. Analysis revealed that large droplets were more concentrated than smaller cloud droplets by a factor of 1.5 for sea-salt-derived species. Cloud water concentrations of ionic species were generally five times greater the concentrations of the same ions in rain water. Aqueous-phase solute concentrations in cloud varied over two orders of magnitude but generally were quite low, correlated to each other and to aerosol (CN) concentration, but negatively correlated to LWC. Air-equivalent solute concentrations were calculated, allowing the detection of the influence of air-mass trajectory on cloud-water composition. A multivariate statistical analysis of the cloud water data suggested sea salt, biogenic, crustal, and anthropogenic emission source contributions; the last two sources existed only for continental air-mass trajectories. Coastal and oceanic trajectories were selected for the purpose of estimating a northern hemisphere, mid-latitude, marine, background cloud water composition of 8 neq m(-3) non-sea salt SO42- and 4 neq m(-3) NO3-. (C) 1997 Elsevier Science Ltd. C1 NOAA,ENVIRONM RES LAB,BOULDER,CO 80303. UNIV WASHINGTON,DEPT CHEM,SEATTLE,WA 98195. RP Vong, RJ (reprint author), OREGON STATE UNIV,COLL OCEAN & ATMOSPHER SCI,CORVALLIS,OR 97331, USA. RI Kowalski, Andrew/A-7515-2008; OI Kowalski, Andrew/0000-0001-9777-9708; McDonald, Noreen/0000-0002-4854-7035 NR 59 TC 31 Z9 32 U1 11 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUL PY 1997 VL 31 IS 13 BP 1991 EP 2001 DI 10.1016/S1352-2310(96)00337-8 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XA623 UT WOS:A1997XA62300008 ER PT J AU McKendry, IG Steyn, DG Lundgren, J Hoff, RM Strapp, W Anlauf, K Froude, F Martin, JB Banta, RM Olivier, LD AF McKendry, IG Steyn, DG Lundgren, J Hoff, RM Strapp, W Anlauf, K Froude, F Martin, JB Banta, RM Olivier, LD TI Elevated ozone layers and vertical down-mixing over the Lower Fraser Valley, BC SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE ozone; vertical mixing; layers aloft; lidar; air quality ID POLLUTANT TRANSPORT; COASTAL ENVIRONMENT; SOUTHERN-CALIFORNIA; LOWER ATMOSPHERE; LOS-ANGELES; SEA-BREEZE; LIDAR AB Vertical profiling data, including lidar, are used to illustrate elevated layer development during two days of the Pacific'93 field study. Results indicate that multiple processes may produce layers. The ''chimney effect'', where pollutants are vented along the heated sidewalls of the valley, is shown to be important, while evidence is also shown for ''convective debris'' contributing to elevated layer development. These processes are similar to those observed in the Los Angeles Basin. However, the study identified a site-specific process in which a strong elevated layer developed as a result of the propagation of a coastally trapped disturbance (manifested as a low-level marine stratus surge). In addition to distinct elevated layers associated with inversion at the top or above the planetary boundary layer, pollutants (including ozone) are shown to persist overnight in the nocturnal residual layer (RL) that caps the stable boundary layer. In order to investigate the effects of vertical down-mixing on surface ozone concentrations, a transilient turbulence model was applied to vertical profile data for 6 August 1993. After sunrise, this showed significant down-mixing of ozone from the nocturnal RL layer. Furthermore, down-mixing was also shown to contribute to surface concentrations in the early afternoon when the growing mixed layer intercepted the elevated layer created by the coastally trapped disturbance. The mechanisms and structures described show strong similarities to those found in the Los Angeles Basin and suggest that these phenomena likely exist in other polluted coastal environments where they may contribute significantly to the observed ground-level concentrations via vertical mixing processes. (C) 1997 Elsevier Science Ltd. C1 ATMOSPHER ENVIRONM SERV,EGBERT,ON,CANADA. NOAA,ERL,ENVIRONM TECHNOL LAB,BOULDER,CO 80303. RP McKendry, IG (reprint author), UNIV BRITISH COLUMBIA,ATMOSPHER SCI PROGRAMME,VANCOUVER,BC V5Z 1M9,CANADA. RI Darby, Lisa/A-8037-2009; Hoff, Raymond/C-6747-2012; Banta, Robert/B-8361-2008 OI Darby, Lisa/0000-0003-1271-0643; NR 21 TC 67 Z9 67 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUL PY 1997 VL 31 IS 14 BP 2135 EP 2146 DI 10.1016/S1352-2310(96)00127-6 PG 12 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XD987 UT WOS:A1997XD98700011 ER PT J AU Banta, RM Shepson, PB Bottenheim, JW Anlauf, KG Wiebe, HA Gallant, A Biesenthal, T Olivier, LD Zhu, CJ McKendry, IG Steyn, DG AF Banta, RM Shepson, PB Bottenheim, JW Anlauf, KG Wiebe, HA Gallant, A Biesenthal, T Olivier, LD Zhu, CJ McKendry, IG Steyn, DG TI Nocturnal cleansing flows in a tributary valley SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE ozone; katabatic flow; dry deposition; downvalley flows; valley outflow jets; Doppler lidar; Vancouver; BC ID PULSED DOPPLER LIDAR; OZONE; CALIFORNIA; DEPOSITION AB During photochemical air pollution episodes in the lower Fraser Valley (LFV) near Vancouver, BC, daytime upvalley flows carried polluted air, with high ozone (O-3) concentrations, into tributary valleys to the north of the LFV. Nighttime flows out of the valleys had low O-3 concentrations, according to surface measurements, and also had low aerosol concentrations, as measured by a scanning Doppler lidar. Analysis of lidar scan data showed that the flows were highly complex, that the relatively clean flow was confined to the lower levels (lowest similar to 500 m) Of the valley, and that regions of strongest outflow were also the regions of ''cleanest'' air. Measurements of NO2 concentrations well above background levels in the outflow indicate that it was formerly polluted air from which O-3 and aerosols had been removed. Possible removal mechanisms were found to be dry deposition in the katabatic (downslope) flows down the valley sidewalls, in agreement with a previous study in a Swiss valley, or fast chemical reactions with NO and NO3. Nearly horizontal lidar scans showed that the valley exit flows penetrated into the LFV, where they merged with the downvalley/land-breeze system along the Eraser River. C1 YORK UNIV,CTR ATMOSPHER CHEM,N YORK,ON M3J 1P3,CANADA. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. PURDUE UNIV,DEPT EARTH & ATMOSPHER SCI,W LAFAYETTE,IN 47907. ATMOSPHER ENVIRONM SERV,DOWNSVIEW,ON,CANADA. COOPERAT INST RES ENVIRONM SCI,BOULDER,CO. UNIV BRITISH COLUMBIA,DEPT GEOG,VANCOUVER,BC,CANADA. RP Banta, RM (reprint author), NOAA,ERL,ENVIRONM TECHNOL LAB,BOULDER,CO 80303, USA. RI Darby, Lisa/A-8037-2009; Shepson, Paul/E-9955-2012; Banta, Robert/B-8361-2008 OI Darby, Lisa/0000-0003-1271-0643; NR 31 TC 63 Z9 64 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUL PY 1997 VL 31 IS 14 BP 2147 EP 2162 DI 10.1016/S1352-2310(96)00359-7 PG 16 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XD987 UT WOS:A1997XD98700012 ER PT J AU Pottier, JL Pryor, SC Banta, RM AF Pottier, JL Pryor, SC Banta, RM TI Synoptic variability related to boundary layer and surface features observed during Pacific '93 SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE synoptic variability; airborne lidar; Doppler lidar; boundary layer stability; topographically induced flows; ozone episode AB Datasets collected during Pacific '93 enable us to construct a three-dimensional view of the atmosphere over the Fraser Valley (southwest British Columbia), and to examine relationships between conditions aloft and those in the boundary layer. Herein, vertical and horizontal profiles of the atmosphere obtained from a ground based Doppler lidar are examined in conjunction with data from an airborne downward looking lidar, meteorological soundings of temperature and wind profiles, synoptic charts and surface pressure analyses. These data sets aid understanding of the flow structure at a number of levels through the boundary layer and the spatial and temporal variability of topographically-induced flow. (C) 1997 Elsevier Science Ltd. C1 INDIANA UNIV,DEPT GEOG,CLIMATE & METEOROL PROGRAM,BLOOMINGTON,IN 47405. NOAA,ENVIRONM TECHNOL LAB,ERL,R E ET2,BOULDER,CO 80303. RP Pottier, JL (reprint author), ENVIRONM CANADA,ENVIRONM CONSERVAT BRANCH,700-1200 W 73RD AVE,VANCOUVER,BC V6P 6H9,CANADA. RI Banta, Robert/B-8361-2008; OI Pryor, S.C./0000-0003-4847-3440 NR 20 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUL PY 1997 VL 31 IS 14 BP 2163 EP 2173 DI 10.1016/S1352-2310(96)00274-9 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XD987 UT WOS:A1997XD98700013 ER PT J AU Matta, MB Cairncross, C Kocan, RM AF Matta, MB Cairncross, C Kocan, RM TI Effect of a polychlorinated biphenyl metabolite on early life stage survival of two species of trout SO BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID CONGENERS; PCB; FISH; EGG C1 UNIV WASHINGTON,SCH FISHERIES,SEATTLE,WA 98195. RP Matta, MB (reprint author), NOAA,BIN C15700,SEATTLE,WA 98115, USA. NR 17 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0007-4861 J9 B ENVIRON CONTAM TOX JI Bull. Environ. Contam. Toxicol. PD JUL PY 1997 VL 59 IS 1 BP 146 EP 151 PG 6 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA XB893 UT WOS:A1997XB89300023 PM 9184055 ER PT J AU Basist, AN Chelliah, M AF Basist, AN Chelliah, M TI Comparison of tropospheric temperatures derived from the NCEP/NCAR reanalysis, NCEP operational analysis, and the microwave sounding unit SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID NATIONAL-METEOROLOGICAL-CENTER; RADIOSONDE VALIDATION; ANOMALIES; MSU; INTERPOLATION; PRECISION; CLIMATE; TRENDS AB The Climate Prediction Center has used atmospheric temperatures for data analysis from the National Centers for Environmental Prediction (NCEP) model since 1979. Unfortunately, model changes have adversely affected the stability of the climatologic fields, introducing time-varying biases in the anomaly patterns of the Climate Diagnostic Data Base (CDDB). Fortunately, NCEP has addressed this issue by rerunning a state-of-the-art model using fixed assimilation, parameterization, and physics in order to derive a true climatology and anomalies. The authors compare the previous CDDB temperatures with those derived from the stable reanalysis. Results show major improvements for climate diagnostics and monitoring. Also compared are the reanalysis temperatures with brightness temperature T-b observed by the Microwave Sounding Units (MSU), flown aboard the National Oceanic and Atmospheric Administration (NOAA) series of polar-orbiting satellites (TIROS-N to NOAA-14). This MSU dataset has a precision of about 0.02 degrees C globally, and it is available from December 1978. Therefore, the 17 levels of the reanalysis level temperature were weighted to simulate the MSU T-b in order to measure its precision over the 17-yr record. Global time series of the spatial correlations between full fields approach 1.0 throughout the entire record, whereas correlations for the anomaly fields can drop below 0.8 during the high sun season in the Northern Hemisphere. In 1994 the correlations drop below 0.65, which is the largest difference between the two datasets. An EOF on the global T-b differences from both datasets identified a relative drift beginning in 1991. The maximum loading was in the tropical Pacific, although it also extended over the tropical Indian Ocean and the Asian landmass. Results indicate that the reanalysis anomalies are getting progressively colder, relative to the MSU, during the early 1990s. The authors associate this drift with the changes in satellite retrievals and a reduction of Soviet Union data during its breakup. Additional sources of bias may be associated with aerosol contamination after the Mt. Pinotuba eruption and/or drift in the NOAA-11 sensor. Although there is a relative offset in the anomalies, the reanalysis temperatures have a better correspondence with the radiosonde network after 1990. Therefore it appears that the bias is associated with an improvement in the reanalysis input data during the last several years. Since changes in the datasets assimilated into the model can introduce a slight bias, new procedures should be developed to minimizes these effects in any future reanalysis. Finally, although the reanalysis has a slight drift in the later years, the comparison with the MSU spatial anomalies generally showed excellent results. The reanalysis represents a substantial improvement over the CDDB for monitoring climate variability. C1 NOAA,NATL WEATHER SERV,NCEP,CLIMATE PREDICT CTR,WASHINGTON,DC 20233. RP Basist, AN (reprint author), NOAA,NESDIS,NATL CLIMA DATA CTR,GLOBAL CLIMATE LAB,151 PATTON AVE,RM 120,ASHEVILLE,NC 28801, USA. NR 28 TC 54 Z9 60 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUL PY 1997 VL 78 IS 7 BP 1431 EP 1447 DI 10.1175/1520-0477(1997)078<1431:COTTDF>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XP114 UT WOS:A1997XP11400003 ER PT J AU Hammond, SR AF Hammond, SR TI Offset caldera and crater collapse on Juan de Fuca Ridge-flank volcanoes SO BULLETIN OF VOLCANOLOGY LA English DT Article DE volcano; sea floor; caldera; crater; spreading center; hydrothermal; Juan de Fuca ID EAST PACIFIC RISE; NORTHEAST PACIFIC; DIKE INJECTION; SONAR SURVEYS; SEAMOUNTS; CREST; OCEAN; AXIS; EVOLUTION; DEPOSITS AB Forty-three volcanoes located along the flanks of the Juan de Fuca Ridge were selected to study relationships between their morphologies and off-axis magmatic processes. The volcanoes occur both in chains consisting of up to seven distinct cones and isolated edifices. Nearly all of the volcanoes are circular, truncated cones with steep flanks and large, relatively flat summit plateaus. In addition, most of these volcanoes also have prominent and distinctly offset calderas or craters. The most striking characteristic of the volcanoes' morphology is that nearly all of their collapse structures are located on the sides of the volcanoes which face the Juan de Fuca Ridge and many are breached with openings toward the ridge. A simple modal based on these observations accounts for these ridge-facing features. As plate motion transports a volcano away from its magma source beneath the lithosphere, the volcano's magma supply conduits tend to lag behind. Eventually these conduits are abandoned and ridgeward collapse structures are formed. It can be inferred from the model that. on average, individual volcanoes were active for approximately 50000 years and that most eruptions took place early in this interval, If most of the cone-building eruptions occurred during the first thousand years or so, associated hydrothermal activity may have temporarily rivaled the present-day yearly time-averaged hydrothermal output along the entire Juan de Fuca ridge axis. RP Hammond, SR (reprint author), OREGON STATE UNIV,HATFIELD MARINE SCI CTR,NOAA,PACIFIC MARINE ENVIRONM LAB,2115 SE OSU DR,NEWPORT,OR 97365, USA. NR 39 TC 16 Z9 16 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0258-8900 J9 B VOLCANOL JI Bull. Volcanol. PD JUL PY 1997 VL 58 IS 8 BP 617 EP 627 DI 10.1007/s004450050166 PG 11 WC Geosciences, Multidisciplinary SC Geology GA XM660 UT WOS:A1997XM66000003 ER PT J AU Beniston, M Diaz, HF Bradley, RS AF Beniston, M Diaz, HF Bradley, RS TI Climatic change at high elevation sites: An overview SO CLIMATIC CHANGE LA English DT Article ID QUELCCAYA ICE CAP; NORTHERN-HEMISPHERE; GLACIER VARIATIONS; CORE RECORDS; HOLOCENE; TRENDS; PRECIPITATION; TEMPERATURE; VARIABILITY; HISTORY AB This paper provides an overview of climatic changes that have been observed during the past century at certain high-elevation sites, and changes in a more distant past documented by a variety of climate-sensitive environmental indicators, such as tree-rings and alpine glaciers, that serve as a measure of the natural variability of climate in mountains over longer time scales. Detailed studies such as those found in this special issue of Climatic Change, as well as those noted in this review, for the mountain regions of the world, advance our understanding in a variety of ways. They are not only helpful to characterize present and past climatological features in the mountainous zones, but they also provide useful information to the climate modeling community. Because of the expected refinements in the physical parameterizations of climate models in coming years, and the probable increase in the spatial resolution of GCMs, the use of appropriate data from high elevation sites will become of increasing importance for model initialization, verification, and intercomparison purposes. The necessity of accurate projections of climate change is paramount to assessing the likely impacts of climate change on mountain biodiversity, hydrology and cryosphere, and on the numerous economic activities which take place in these regions. C1 NOAA,ERL,CDC,BOULDER,CO 80303. UNIV MASSACHUSETTS,AMHERST,MA 01003. RP Beniston, M (reprint author), UNIV FRIBOURG,INST GEOG,CH-1700 FRIBOURG,SWITZERLAND. OI BENISTON, Martin/0000-0002-3782-5458 NR 83 TC 356 Z9 386 U1 13 U2 123 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD JUL-AUG PY 1997 VL 36 IS 3-4 BP 233 EP 251 DI 10.1023/A:1005380714349 PG 19 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XR067 UT WOS:A1997XR06700001 ER PT J AU Diaz, HF Bradley, RS AF Diaz, HF Bradley, RS TI Temperature variations during the last century at high elevation sites SO CLIMATIC CHANGE LA English DT Article ID CLIMATE; PERSPECTIVE; TRENDS AB Differential temperature changes with altitude can shed light on the relative importance of natural versus anthropogenic climatic change. There has been heightened interest in this subject recently due to the finding that high-elevation tropical glaciers have been retreating and that significant melting from even the highest alpine regions has occurred in some areas during the past 20 years or so, as recorded in ice core records, which do not reveal any similar period during previous centuries to millennia. In this paper we find evidence for appreciable differences in mean temperature changes with elevation during the last several decades of instrumental records. The signal appears to be more closely related to increases in daily minimum temperature than changes in the daily maximum. The changes in surface temperature vary spatially, with Europe (particularly western Europe), and parts of Asia displaying the strongest high altitude warming during the period of record. High-elevation climate records of long standing taken at a number of mountain tops throughout the world, but primarily in Europe, are available from a number of countries. In some cases, meteorological observations at these unique mountain sites have been discontinued for a variety of reasons, usually budgetary. It is hoped that the papers published in this special issue of Climatic Change can contribute to a reassessment of the value of continuing climate measurements at these mountain observatories by the appropriate entities, so that we may continue to have access to climate information from the 'tops of the world'. C1 UNIV MASSACHUSETTS,DEPT GEOSCI,AMHERST,MA 01003. RP Diaz, HF (reprint author), NOAA,ERL,CDC,325 BROADWAY,BOULDER,CO 80303, USA. NR 34 TC 181 Z9 191 U1 7 U2 41 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD JUL-AUG PY 1997 VL 36 IS 3-4 BP 253 EP 279 DI 10.1023/A:1005335731187 PG 27 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XR067 UT WOS:A1997XR06700002 ER PT J AU Code, JE Antonucci, JM Bennett, PS Schumacher, GE AF Code, JE Antonucci, JM Bennett, PS Schumacher, GE TI Photoactivated dentin bonding with N-phenyliminodiacetic acid SO DENTAL MATERIALS LA English DT Article ID HARD TOOTH TISSUES; ADHESIVE; POLYMERIZATION; PHENYLGLYCINE; INITIATION AB Objectives. The overall objective of this study was to correlate adhesive resin and polymerization initiator chemistry with bonding to dentin that had been treated with N-phenyliminodiacetic acid (PIDAA), a self-etching primer with initiator and co-initiator potential. The hypotheses to be tested were that: (1) the nature of the adhesive resin and (2) the type of polymerization initiator system are critical factors that can influence the bonding of composite restoratives to dentin. Methods. Three types of bonding resins: (A) a non-carboxylic acid bonding resin (BisGMA/HEMA); (B) a carboxylic acid monomer (PMDM, the control); and (C) a combination system (BisGMA/HEMA/PMDM), along with two types of initiator systems: (1) a self-curing chemical initiator system based on PIDAA and (2) a dual-cure system involving camphorquinone, PIDAA, and visible light irradiation, were tested with a randomized 3 x 2 full factorial design. Solutions of each resin in acetone were tested with and without camphorquinone. Solution (A) was a 50% solution of 1:1 BisGMA/HEMA; Solution (B), a 10% solution of PMDM; and Solution (C), a 50% solution of 2:2:1 BisGMA/HEMA/PMDM in the ratio of 2:2:1. All percents were on a mass basis. (The photoactivated solutions of A, B, and C also contained 0.5% camphorquinone based on the mass of the resin.) Ninety composite-to-dentin specimens were prepared by a 2-step protocol: 1) 60 s application of 20 mu L of 0.3 mol/L PIDAA in 1:1 v/v acetone/H2O; 2) 60 s application of 20 mu L of one of the six resin solutions, followed by 60 s visible light irradiation. A visible light-activated composite (Silux, 3M) was then applied to each treated surface and irradiated for 60 s. Specimens were stored in distilled H2O (22 degrees C, 24 h) before shear bond testing. The summary statistics were calculated and a two-way ANOVA and Duncan's Multiple Range test were used to discern if the two factors significantly affected the mean shear bond strength. Results. Mean shear bond strengths and standard deviations were obtained (with and without camphorquinone, respectively): (A), 11.0 MPa +/- 3.9 and 4.1 MPa +/- 4.9; (B), 27.0 MPa +/- 5.3 and 13.7 MPa +/- 5.6; (C), 18.3 MPa +/- 5.3 and 7.0 MPa +/- 5.2. The use of camphorquinone significantly enhanced the mean shear bond strengths obtained with the carboxylic, non carboxylic and combination monomer based adhesive systems (p < 0.0001). For PIDAA-treated dentin, moderate shear bond strengths were obtained with a non-carboxylic acid resin solution containing camphorquinone. The addition of both PMDM and camphorquinone to this resin further improved the shear bond strengths. The highest mean shear bond strength was obtained with the combination of PMDM and camphorquinone (p < 0.05). Significance. These results suggest that formulations based on PIDAA, PMDM and camphorquinone are more effective as bonding systems than those formulations without PMDM and camphorquinone. PIDAA, a self-etching primer with initiator and co-initiator abilities, appears to interact positively with both carboxylic acid monomers such as PMDM and the photooxidant camphorquinone. C1 Natl Inst Stand & Technol, Ctr Clin, Natl Inst Hlth, Gaithersburg, MD 20899 USA. Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD USA. RP Antonucci, JM (reprint author), Natl Inst Stand & Technol, Dent & Med Mat Grp, Bldg 224,Room A-139, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [DE09322, YO1 DE30001] NR 29 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0109-5641 J9 DENT MATER JI Dent. Mater. PD JUL PY 1997 VL 13 IS 4 BP 252 EP 257 DI 10.1016/S0109-5641(97)80037-1 PG 6 WC Dentistry, Oral Surgery & Medicine; Materials Science, Biomaterials SC Dentistry, Oral Surgery & Medicine; Materials Science GA 110DJ UT WOS:000075364600006 PM 11696905 ER PT J AU Ballance, LT Pitman, RL Reilly, SB AF Ballance, LT Pitman, RL Reilly, SB TI Seabird community structure along a productivity gradient: Importance of competition and energetic constraint SO ECOLOGY LA English DT Article DE body size; community ecology; competition; energetic constraint; energetic cost of fight; feeding flocks; flight proficiency; productivity gradient; seabird communities; seabird distribution; species composition; tropical Pacific ID EASTERN TROPICAL PACIFIC; INTERSPECIFIC COMPETITION; BODY-SIZE; FLIGHT ENERGETICS; FIELD EXPERIMENTS; SOOTY TERNS; OCEAN; ASSEMBLAGES; ECOLOGY; PHYTOPLANKTON AB The oceanic eastern tropical Pacific supports a speciose seabird community that feeds in flocks and depends for food on schools of tunas and dolphins, which force prey to the surface. We analyzed data collected throughout an area of 40 x 10(6) km(2) of open ocean over 10 years (1979-1988) during 1136 at-sea days, from 1750 feeding flocks comprising 51 688 birds of 49 species. a PCA identified three distinct hock types based on species composition: ''Sooty Tern Flocks'' (n = 941 flocks) with a large number of Sooty Terns (Sterna fuscata), ''Juan-Wedge Flocks'' (n = 402 flocks) with a large number of Juan Fernandez Petrels (Pterodroma externa) and Wedge-tailed Shearwaters (Puffinus pacificus), and ''Booby Flocks'' (n = 407 flocks) with a large number of Red-footed and Masked Boobies (Sula sula and S. dactylatra, respectively). Flock types exhibited largely disjunct distributions that mirrored patterns in thermocline depth and surface water chlorophyll content. Sooty Tern Flocks occurred in areas with deepest thermocline (77.6 m) and lowest chlorophyll (0.14 mg/m(3)), Juan-Wedge Flocks in areas of intermediate thermocline (68.8 m) and chlorophyll (0.16 mg/m(3)), and Booby Flocks in areas of shallowest thermocline (62.5 m) and highest chlorophyll (0.17 mg/m(3)). These differences were statistically significant. As thermocline depth and surface water chlorophyll are reliable indicators of surface water productivity, we conclude that Sooty Tern Flocks foraged in waters of low productivity, Juan-Wedge Flocks in waters of intermediate productivity, and Booby Flocks in waters of highest productivity. Differences in published cost-of-flight values support the hypothesis that energetic constraint determines flock structure at the low-productivity end of the system. Sooty Terns have the lowest flight costs (4.8 W) and feed in waters of lowest productivity. Flight costs are progressively higher for those species feeding in more productive waters (9.9 W for Wedge-tailed Shearwaters, 19.0 W for Red-footed Boobies). Differences in body size support the hypothesis that interference competition determines hock structure at the high-productivity end of the system. The largest species, Masked Boobies (1987 g) and Red-footed Boobies (1003 g), feed in areas of highest productivity; progressively smaller species, Juan Fernandez Petrels (430 g) and Wedge-tailed Shearwaters (388 g), and Sooty Terns (180 g), feed in areas of decreasing productivity. We hypothesize that this community is largely structured by two factors, competition and energetic constraint, that operate at opposite ends of a productivity gradient. As productivity decreases (low prey abundance), flight proficiency is increasingly important because only species with relatively low flight costs will be able to transit between prey patches. As productivity increases (high prey abundance), competitive ability is increasingly important because competitive dominants will exclude other species from feeding flocks. Our hypothesis is in accordance with empirical data and theoretical models designed to explain factors structuring communities for a wide variety of habitats and taxa. C1 UNIV CALIF LOS ANGELES, DEPT BIOL, LOS ANGELES, CA 90024 USA. RP Ballance, LT (reprint author), SW FISHERIES SCI CTR, 8604 LA JOLLA SHORES DR, LA JOLLA, CA 92037 USA. NR 93 TC 125 Z9 133 U1 0 U2 32 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 0012-9658 EI 1939-9170 J9 ECOLOGY JI Ecology PD JUL PY 1997 VL 78 IS 5 BP 1502 EP 1518 DI 10.1890/0012-9658(1997)078[1502:SCSAAP]2.0.CO;2 PG 17 WC Ecology SC Environmental Sciences & Ecology GA XK929 UT WOS:A1997XK92900021 ER PT J AU Xue, HB Sunda, WG AF Xue, HB Sunda, WG TI Comparison of [Cu2+] measurements in lake water determined by ligand exchange and cathodic stripping voltammetry and by ion-selective electrode SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID NATURAL ORGANIC-LIGANDS; COPPER COMPLEXATION; SARGASSO-SEA; SPECIATION; SEAWATER; COMPETITION; EXTRACTION; CHELATORS; PACIFIC AB While there has been a proliferation of techniques for measuring free metal ion concentrations and complexation in natural waters, there has been little direct intercomparison among methods. Here we report the results of an intercomparison among different methods used to determine free cupric ion concentration ([Cu2+]) and organic complexation in lake water samples. The techniques used were potentiometric measurement with a cupric ion-selective electrode (Cu-ISE) and ligand exchange methods involving the addition of three well-characterized ligands with different binding affinities for copper (catechol, 8-hydroxyquinoline, and tropolone) followed by measurement of the Cu chelates of these ligands by adsorptive differential pulse cathodic stripping voltammetry (DPCSV). Good agreement was found among relationships between [Cu2+] and the total concentration of natural copper species ([Cu-nat]) determined via titration with the three ligand exchange/DPCSV methods. Relationships between [Cu2+] and [Cu-nat] measured by these methods also agreed with those determined with a cupric ion electrode within the overlapping range of detection windows for each method ([Cu-nat] = 40-100 nM). At lower Cu concentrations, the Cu electrode gave erroneously high [Cu2+] readings, apparently due to a failure of the electrode membrane to equilibrate with the sample. The agreement among the different methods provides support for the validity of each individual method of measuring [Cu2+] and natural Cu complexation. By combining Cu titration data measured by DPCSV and Cu-ISE we obtained a more complete description of the Cu-complexing characteristics of water samples from two Swiss lakes than could be obtained with any single method. Equilibrium modeling of this composite data indicated the presence of at least three ligand classes. These ranged in concentration from 38 +/- 19 nM far the strongest binding ligand class, which had conditional binding constants in the range of 10(15) at pH 7.8-8.0, to 8 +/- 2 mu M for the weakest class of ligands, which had 8 conditional constant of 10(8.6) M-1. C1 NOAA, NATL MARINE FISHERIES SERV, BEAUFORT LAB, BEAUFORT, NC 28516 USA. SWISS FED INST ENVIRONM SCI & TECHNOL, LIMNOL RES CTR, CH-6047 KASTANIENBAUM, SWITZERLAND. NR 25 TC 76 Z9 77 U1 0 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD JUL PY 1997 VL 31 IS 7 BP 1902 EP 1909 DI 10.1021/es960551i PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XH483 UT WOS:A1997XH48300030 ER PT J AU Lauenstein, GG Cantillo, AY AF Lauenstein, GG Cantillo, AY TI Analytical evaluation of laboratories wishing to perform environmental characterization studies SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE quality assurance; analytical testing; contracts; trace elements; organic contaminants AB Laboratories competing to analyze bivalve mollusks under contract to the National Oceanic and Atmospheric Administration's Mussel Watch Project were required to undergo analytical tests of their ability to quantify environmental contaminants as part of the contract evaluation process. During the 1989 selection process laboratories that appeared to qualify on the basis of their written proposals were provided a gravimetrically prepared solution with ''unknown'' quantities of an undefined number of organic contaminants that are regularly quantified for the Mussel Watch Project. In 1994, competing laboratories were once again tested but this time using matrix materials for the quantification of both trace elements and organic contaminants. Three laboratory groups participated in the exercises. For the 1989 gravimetrically prepared solutions, all participating laboratories were able to identify the contaminants present and in all but two cases were able to report values to within +/-25% of the known values. In 1994, all laboratories were within the acceptance criteria for the quantification of trace elements in the homogenate sample. Analytical laboratory testing is an important first step to ensure that environmental characterization studies are successful. RP Lauenstein, GG (reprint author), NOAA, NATL STATUS & TRENDS PROGRAM, N ORCA21, 1305 EAST WEST HIGHWAY, SILVER SPRING, MD 20910 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD JUL PY 1997 VL 16 IS 7 BP 1345 EP 1350 DI 10.1897/1551-5028(1997)016<1345:AEOLWT>2.3.CO;2 PG 6 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA XM539 UT WOS:A1997XM53900002 ER PT J AU VanDolah, RE Maier, PP Fulton, MH Scott, GI AF VanDolah, RE Maier, PP Fulton, MH Scott, GI TI Comparison of azinphosmethyl toxicity to juvenile red drum (Sciaenops ocellatus) and the mummichog (Fundulus heteroclitus) SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE azinphosmethyl; fish; acute toxicity; sublethal effects ID ESTUARINE AB The acute and sublethal responses of juvenile red drum (Sciaenops ocellatus) and mummichogs (Fundulus heteroclitus) were evaluated to determine the relative effects of exposure to azinphosmethyl (APM). Acute responses were based on 96-h static-renewal bioassays at salinities of 5 and 20%. Sublethal responses were based on inhibition of brain acetylcholinesterase (AChE) activity after 24-h exposures at each salinity and by measuring behavioral and stamina (swimming ability) responses of each species. The acute toxicity tests indicated that juvenile red drum were significantly more sensitive to APM than were mummichogs (mean lethal concentration [LC50] = 6.3-7.1 mu g/L versus 65-84 mu g/L). No significant differences were noted in the LC50 response of either species at reduced salinities. In contrast, mummichogs were more sensitive to APM-induced inhibition of brain AChE activity than juvenile red drum (mean effective concentration [EC50] < 1.0 mu g/L in mummichogs and >5.0 mu g/L in red drum). Behavioral response tests indicated that neither species avoided pesticide-laden water, which may increase their vulnerability to APM runoff. Stamina assays indicated that juvenile red drum experienced a decreased ability to swim after a 6-h exposure to 12 mu g/L APM. Mummichogs were less sensitive with respect to the effects of APM on swimming ability at concentrations as high as 24 mu g/L APM (p < 0.1). C1 NATL MARINE FISHERIES SERV,SE FISHERIES CTR,CHARLESTON LAB,CHARLESTON,SC 29422. RP VanDolah, RE (reprint author), S CAROLINA DEPT NAT RESOURCES,MARINE RESOURCES RES INST,POB 12559,CHARLESTON,SC 29422, USA. NR 29 TC 25 Z9 27 U1 0 U2 2 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD JUL PY 1997 VL 16 IS 7 BP 1488 EP 1493 DI 10.1897/1551-5028(1997)016<1488:COATTJ>2.3.CO;2 PG 6 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA XM539 UT WOS:A1997XM53900023 ER PT J AU Cadrin, SX Vaughan, DS AF Cadrin, SX Vaughan, DS TI Retrospective analysis of virtual population estimates for Atlantic menhaden stock assessment SO FISHERY BULLETIN LA English DT Article ID ERRORS AB Historical and retrospective comparisons of Atlantic menhaden virtual population analyses (VPA) from 1955 to 1995 revealed substantial inconsistency in estimates of management variables in the last year of stock assessments. Estimates of management variables from several historical stock assessments were generally consistent throughout most of the time series. In the last two years, however, historical estimates have deviated from revised estimates. Relative performance of alternative ad hoc methods for estimating fully recruited fishing mortality (F) in terminal years showed that all methods were imprecise, but conventional catch-curve estimates were unbiased and had the least retrospective inconsistency. Retrospective differences in terminal estimates of age-1 F by separable VPA ranged widely for eight alternative settings but were clearly minimized by using seven years of catch data. The general magnitude of retrospective difference was +/- 1.2 billion recruits (46% relative difference), +/-9,000 metric tons of spawning stock biomass (33% relative difference), and +/-4.7 percent maximum spawning potential (106% relative difference). Retrospective differences in recruitment, spawning stock biomass, and spawning potential were positively skewed but not biased, indicating that the frequency of positive and negative inconsistencies are equal but that the positive differences are much greater in magnitude. The skewed distribution of retrospective inconsistency should be considered for managing the Atlantic menhaden fishery. C1 MASSACHUSETTS DIV MARINE FISHERIES,POCASSET,MA 02559. NOAA,NATL MARINE FISHERIES SERV,BEAUFORT LAB,BEAUFORT,NC 28516. NR 33 TC 11 Z9 11 U1 0 U2 2 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1997 VL 95 IS 3 BP 445 EP 455 PG 11 WC Fisheries SC Fisheries GA XH003 UT WOS:A1997XH00300004 ER PT J AU Hettler, WF Peters, DS Colby, DR Laban, EH AF Hettler, WF Peters, DS Colby, DR Laban, EH TI Daily variability in abundance of larval fishes inside Beaufort Inlet SO FISHERY BULLETIN LA English DT Article ID NORTH-CAROLINA; ATLANTIC MENHADEN; BREVOORTIA-TYRANNUS; GROWTH; ICHTHYOPLANKTON; PATTERNS; ESTUARY; BAY AB We measured the daily abundance of larvae of eight species of ocean-spawned, estuarine-dependent fishes to determine the effect of sampling frequency on the mean and variance estimates during larval immigration past a permanent sampling station inside Beaufort Inlet, North Carolina, mid-November 1991 to mid-april 1992. Species of interest were Brevoortia tyrannus, Lagodon rhomboides, Leiostomus xanthurus, Micropogonias undulatus, Mugil cephalus, Paralichthys albigutta, P. dentatus, and P. lethostigma. Our data suggest that sampling at intervals >7 days can lead to excessive variance in abundance estimates. For all species, abundance varied as much as an order of magnitude from night to night. Proportional residuals from polynomial models of the seasonal recruitment pattern for a given species were used to assess the potential influence of nine environmental variables on daily densities. Twenty-seven of 72 correlations of proportional residuals with environmental variables were significant (P<0.05). Proportional residuals were positively correlated with time after dusk for six of eight species and were negatively correlated with turbidity for five of eight species. However, interpretation of correlations must be done cautiously because a species' recruitment pattern may coincide with normal seasonal change in one or more environmental variables. Variability in transport of larvae, from offshore to near the inlet and then through the inlet to the station, probably influences species abundance at the sampling station more than locally acting environmental variables. Daily collections of B. tyrannus larvae provided otoliths (n=1,341) showing that a large number of younger larvae, averaging 55 days posthatch, arrived at the station in mid-March on the date of maximum observed daily density (160 larvae per 100 m(3)). RP Hettler, WF (reprint author), NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,101 PIVERS ISL RD,BEAUFORT,NC 28516, USA. NR 19 TC 31 Z9 31 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1997 VL 95 IS 3 BP 477 EP 493 PG 17 WC Fisheries SC Fisheries GA XH003 UT WOS:A1997XH00300007 ER PT J AU Nichol, DG AF Nichol, DG TI Effects of geography and bathymetry on growth and maturity of yellowfin sole, Pleuronectes asper, in the eastern Bering Sea SO FISHERY BULLETIN LA English DT Article ID SEXUAL MATURITY; SIZE; AGE AB Length at age, length at maturity, and age at maturity of yellowfin sole, Pleuronectes asper, in the eastern Bering Sea, are influenced by area of sampling and bottom depth. Yellowfin sole sampled during spring and summer bottom trawl surveys (1982-94) grew faster in the northwest area compared with the southeast area. Mean lengths at age were generally more than 2 cm greater than those for southeast fish at ages greater than 10 years. Length at 50% maturity in females during 1993 and 1994 was respectively 2.3 cm and 0.94 cm larger in the northwest area than in the southeast area. In contrast, there was no apparent difference in age at 50% maturity between areas. Spring-summer patterns in bathymetric habitation of yellowfin sole differ for immature and mature individuals and cause a potential bias in estimates of growth and maturity. There is a clear relation between length and depth for immature fish, with older, immature fish inhabiting deeper water. In contrast, mature fish distribute similarly by size across a wide range of bottom depths. As a result, estimates of length and age at 50% maturity (L-50, A(50)) tended to increase with increasing bottom depth. Because current resource assessment surveys do not sample the shallowest areas of the summer distribution of yellowfin sole, estimates of L-50 and A(50) are inherently biased high. RP Nichol, DG (reprint author), NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115, USA. NR 24 TC 9 Z9 9 U1 0 U2 2 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1997 VL 95 IS 3 BP 494 EP 503 PG 10 WC Fisheries SC Fisheries GA XH003 UT WOS:A1997XH00300008 ER PT J AU Zimmermann, M AF Zimmermann, M TI Maturity and fecundity of arrowtooth flounder, Atheresthes stomias, from the Gulf of Alaska SO FISHERY BULLETIN LA English DT Article ID ATRESIA AB Maturity and total fecundity are reported for arrowtooth flounder, Atheresthes stomias, from the Gulf of Alaska. Histological examination of both ovarian and testicular tissues revealed that the maturity state of both sexes could not be determined reliably by macroscopic assessment. Maturity for females ranged from the early perinucleus to the migratory nucleus stage; none of the fish had postovulatory follicles or hydrated oocytes, indicating all samples were collected prior to the spawning season. Condition factor (CF), gonadosomatic index (GSI), and hepatosomatic index (HSI) increased significantly in the later stages of female development. Eyed-side ovarian lobes were significantly heavier than blind-side lobes, but oocyte size and density (oocytes/gram) did not vary between lobes of the ovary or within the individual ovarian lobes. Total fecundity increased exponentially with length (F=0.0429 x L-4.020) and linearly with somatic weight (F=350.4 x W - 138,482), with estimates ranging from 250,000 to 2,340,000 oocytes. Histological analysis of tissues indicated that females reach 50% maturity (L-50) at 47 cm, males at 42 cm. This estimate of male L-50 is probably high because no males in this study were ready to spawn, whereas a decrease in CF and an increase in GSI indicate body changes at a size of 30-35 cm. C1 NOAA,NATL MARINE FISHERIES SERV,SEATTLE,WA 98115. RP Zimmermann, M (reprint author), NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. NR 21 TC 19 Z9 22 U1 0 U2 2 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1997 VL 95 IS 3 BP 598 EP 611 PG 14 WC Fisheries SC Fisheries GA XH003 UT WOS:A1997XH00300016 ER PT J AU Thedinga, JF Moles, A Fujioka, JT AF Thedinga, JF Moles, A Fujioka, JT TI Mark retention and growth of jet-injected juvenile marine fish SO FISHERY BULLETIN LA English DT Article ID SALMON RP Thedinga, JF (reprint author), NOAA, NATL MARINE FISHERIES SERV, ALASKA FISHERIES SCI CTR, AUKE BAY LAB, 11305 GLACIER HIGHWAY, JUNEAU, AK 99801 USA. NR 17 TC 2 Z9 2 U1 0 U2 0 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 JUL PY 1997 VL 95 IS 3 BP 629 EP 633 PG 5 WC Fisheries SC Fisheries GA XH003 UT WOS:A1997XH00300019 ER PT J AU Larsen, DA Dickey, JT Dickhoff, WW AF Larsen, DA Dickey, JT Dickhoff, WW TI Quantification of salmon alpha- and thyrotropin (TSH) beta-subunit messenger RNA by an RNase protection assay: Regulation by thyroid hormones SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article ID UNDERYEARLING COHO SALMON; ONCORHYNCHUS-KISUTCH; RIBONUCLEIC-ACIDS; SOLUTION HYBRIDIZATION; CHINOOK SALMON; TELEOST FISH; PITUITARY; CLONING; GONADOTROPIN; EXPRESSION AB In order to study salmon thyroid-stimulating hormone (TSH), we designed a highly specific, sensitive, and rapid RNase protection assay (RPA) for quantification of steady-state levels of salmon TSH beta-subunit mRNA expression. The cDNA encoding the beta-subunit of TSH was isolated from coho salmon pituitary total RNA by reverse-transcriptase PCR, partially sequenced, and used as template for synthesizing a radioactively labeled, sequence-specific, antisense probe, and sense standard for the RPA. This assay along with a similar RPA previously designed for coho salmon total alpha-subunit mRNA, was used to examine the effects of feeding T3 (0, 10, 100 mu g/g) and methimazole (a thyroid inhibitor) (2.5 mg/g) on TSH subunit gene expression after 2 and 4 weeks. The low dose of T3 (10 mu g/g) caused no change in TSH beta mRNA after 2 and 4 weeks and a transient increase in alpha mRNA after 2; weeks, followed by no significant effect after 4 weeks. The high dose of T3 (100 mu g/g) caused a decrease in TSH beta mRNA after 4 weeks and no change in total alpha mRNA after 2 and 4 weeks. In contrast, methimazole treatment; caused significant increases in both TSH beta mRNA (250%) and alpha mRNA (50%) levels after 4 weeks. These findings confirm that, as in mammals, TSH alpha- and beta-subunit expression in teleosts may be differentially regulated by negative feedback from the thyroid hormones. (C) 1997 Academic Press. C1 UNIV WASHINGTON,SCH FISHERIES,SEATTLE,WA 98195. RP Larsen, DA (reprint author), NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,2725 MONTLAKE BLVD E,SEATTLE,WA 98112, USA. NR 50 TC 29 Z9 29 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0016-6480 J9 GEN COMP ENDOCR JI Gen. Comp. Endocrinol. PD JUL PY 1997 VL 107 IS 1 BP 98 EP 108 DI 10.1006/gcen.1997.6900 PG 11 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA XF363 UT WOS:A1997XF36300010 PM 9208309 ER PT J AU Pinkel, R Merrifield, M McPhaden, M Picaut, J Rutledge, S Siegel, D Washburn, L AF Pinkel, R Merrifield, M McPhaden, M Picaut, J Rutledge, S Siegel, D Washburn, L TI Solitary waves in the western equatorial Pacific Ocean SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SULU SEA; MICROSTRUCTURE; SOLITONS; PACKETS; SHELF; BAY AB During the spring tides of early January and February 1993, groups of solitary internal waves were observed propagating through the Intensive Flux Array of the TOGA COARE experiment. The waves appear to originate near the islands of Nugarba (3 degrees S 30'S - 154 degrees 30'E). They travel north-eastward at 2.5-3 m/s, closely coupled with the semi-diurnal baroclinic tide. Peak amplitudes exceed 60 m. Velocities are in excess of .8 m/s. Sea-surface vertical displacements of order .3 m can be inferred directly from the lateral acceleration of surface waters. The Equatorial Undercurrent is displaced by soliton passage but apparently is unaffected otherwise. The intrinsic shear of the solitary crests is small compared to ambient equatorial shears. The crests, while not themselves unstable, are effective at triggering instabilities on the background flow. The motions potentially contribute 10-15 Watts/m(2) to the flux of heat into the mixed layer. C1 UNIV HAWAII,HONOLULU,HI 96822. NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. ORSTOM,GRP SURTROPAC,NOUMEA,NEW CALEDONIA. COLORADO STATE UNIV,FT COLLINS,CO 80523. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. RP Pinkel, R (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,CODE 0213,LA JOLLA,CA 92093, USA. RI Siegel, David/C-5587-2008; McPhaden, Michael/D-9799-2016 NR 18 TC 12 Z9 12 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1997 VL 24 IS 13 BP 1603 EP 1606 DI 10.1029/97GL01610 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XJ380 UT WOS:A1997XJ38000015 ER PT J AU Musman, S Jahn, JM LaBelle, J Swartz, WE AF Musman, S Jahn, JM LaBelle, J Swartz, WE TI Imaging spread-F structures using GPS observations at Alcantara, Brazil SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EQUATORIAL; IRREGULARITIES AB During October 1994, a dual-frequency GPS receiver was operated in Alcantara, Brazil, at the same site where the Cornell University Portable Radar Interferometer (CUPRI) was performing spread-F measurements for an ongoing rocket campaign. We present data for two nights during which several spread-F plumes drifted through the field-of-view of CUPRI. Fluctuations in the total electron content (TEC) measured with the GPS receiver were correlated with those plumes. We define a ''roughness'' measure from a specialized high frequency filter. Plots of ''roughness'' in a magnetic longitude versus time space show initially low activity followed by regions of dramatic localized onsets and a slower subsequent decline. Features in the roughness image are well-correlated with plumes in the CUPRI backscatter power map. C1 NOAA,NATL GEOPHYS DATA CTR,BOULDER,CO 80303. DARTMOUTH COLL,DEPT PHYS & ASTRON,HANOVER,NH 03755. CORNELL UNIV,DEPT ELECT ENGN,ITHACA,NY 14853. RP Musman, S (reprint author), NOAA,GEOSCI LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 12 TC 23 Z9 23 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1997 VL 24 IS 13 BP 1703 EP 1706 DI 10.1029/97GL00834 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XJ380 UT WOS:A1997XJ38000040 ER PT J AU Kedzierski, MA AF Kedzierski, MA TI Effect of inclination on the performance of a compact crazed plate condenser and evaporator SO HEAT TRANSFER ENGINEERING LA English DT Article ID HEAT-TRANSFER; PRESSURE-DROP AB This study experimentally quantified the change in heat transfer and pressure drop associated with tilting a compact brazed heat exchanger from the intended vertical position. Both clock wise and counterclockwise rotations within a plane perpendicular to the fittings were examined. A SWEP B15 x 36 was tested as an R-22 evaporator and condensor under fixed refrigerant state conditions suitable to high-efficiency water-source heat pumps. This study showed that a substantial performance penalty occurred when evaporator was rotated past 30 degrees from the vertical. The evaporator hear transfer in the horizontal position was 60-75% of the vertical value. For a rotation angle of 30 degrees the degraded heat transfer was within 5% of the vertical value. Rotation direction and entering refrigerant state had little effect on the performance of the evaporator for rotation angles less than 60 degrees. Only when the evaporator was rotated to the horizontal position did rotation direction and refrigerant state have much effect. At the horizontal position, a subcooled-entering refrigerant and a counter clockwise rotation both tended to lessen the evaporator heat transfer degradation. Rotation of the condenser to the horizontal position improved the overall heat transfer coefficient by approximately 17-30%. Rotation direction had a negligible effect on the performance of the condenser for angles less than 60 degrees. Both the evaporator and condenser pressure drops were influenced by flow distribution changes as the heat exchangers were rotated. RP Kedzierski, MA (reprint author), NIST,US DEPT COMMERCE,THERMAL MACHINERY GRP,BLDG & FIRE RES LAB,BLDG 226,ROOM B114,GAITHERSBURG,MD 20899, USA. NR 10 TC 16 Z9 16 U1 0 U2 1 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0145-7632 J9 HEAT TRANSFER ENG JI Heat Transf. Eng. PD JUL-SEP PY 1997 VL 18 IS 3 BP 25 EP 38 DI 10.1080/01457639708939899 PG 14 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA XR310 UT WOS:A1997XR31000002 ER PT J AU Beichl, I Sullivan, F AF Beichl, I Sullivan, F TI (Monte Carlo) time after time SO IEEE COMPUTATIONAL SCIENCE & ENGINEERING LA English DT Article ID SIMULATION; GROWTH RP NIST, COMP & APPL MATH LAB, GAITHERSBURG, MD 20899 USA. NR 8 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 90720-1314 USA SN 1070-9924 J9 IEEE COMPUT SCI ENG JI IEEE Comput. Sci. Eng. PD JUL-SEP PY 1997 VL 4 IS 3 BP 91 EP 94 DI 10.1109/99.615434 PG 4 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Mathematics, Applied SC Computer Science; Engineering; Mathematics GA XX979 UT WOS:A1997XX97900014 ER PT J AU Wiebe, PH Stanton, TK Benfield, MC Mountain, DG Greene, CH AF Wiebe, PH Stanton, TK Benfield, MC Mountain, DG Greene, CH TI High-frequency acoustic volume backscattering in the Georges Bank coastal region and its interpretation using scattering models SO IEEE JOURNAL OF OCEANIC ENGINEERING LA English DT Article DE coastal oceanography; forward problem; Georges Bank; high-frequency acoustics; internal waves; inverse problem; volume backscattering models; zooplankton volume backscattering ID SUSPENDED SAND CONCENTRATION; SOUND-SCATTERING; ZOOPLANKTON DISTRIBUTIONS; LANGMUIR CIRCULATIONS; VERTICAL-DISTRIBUTION; SEDIMENTARY FURROWS; EUPHAUSIA-SUPERBA; FLUID CYLINDERS; FISH ABUNDANCE; FINITE LENGTH AB High-frequency (120 and 420 kHz) sound was used to survey sound scatterers in the water over Georges Bank, In addition to the biological sound scatterers (the plankton and micronekton), scattering associated with internal waves and suspended sediment was observed, Volume backscattering was more homogeneous in the vertical dimension (with occasional patches) in the shallow central portion of the Bank where there is significant mixing. In the deeper outer portion of the Bank where the water is stratified, volume backscattering was layered and internal waves modulated the vertical position of the layers in the pycnocline, The internal saves typically had amplitudes of 5-20 m, but sometimes much higher, Species composition and size data from samples of the animals and suspended sediment used in conjunction with acoustic scattering models revealed that throughout the region the animals generally dominate the scattering, but there are times and places where sand particles (suspended as high as up to the sea surface) can dominate. The source of the scattering in the internal waves is probably due to a combination of both animals and sound-speed microstructure. Determination of their relative contributions requires further study. C1 LOUISIANA STATE UNIV,COASTAL FISHERIES INST,BATON ROUGE,LA 70803. NE FISHERIES SCI CTR,WOODS HOLE,MA 02543. CORNELL UNIV,ITHACA,NY 14853. RP Wiebe, PH (reprint author), WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543, USA. OI Wiebe, Peter/0000-0002-6059-4651 NR 71 TC 51 Z9 51 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0364-9059 J9 IEEE J OCEANIC ENG JI IEEE J. Ocean. Eng. PD JUL PY 1997 VL 22 IS 3 BP 445 EP 464 DI 10.1109/48.611135 PG 20 WC Engineering, Civil; Engineering, Ocean; Engineering, Electrical & Electronic; Oceanography SC Engineering; Oceanography GA XN699 UT WOS:A1997XN69900005 ER PT J AU Mansoor, A Martzloff, FD AF Mansoor, A Martzloff, FD TI Driving high surge currents into long cables: More begets less SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article; Proceedings Paper CT 1996 IEEE/PES Summer Meeting CY JUL 28-AUG 01, 1996 CL DENVER, CO SP IEEE Power Engn Soc, PES AB Reality checks can and should be applied to proposals for characterizing the surge environment and application of surge-protective devices (SPDs) to end-user, low-voltage power systems, One such check is the fact that driving a large current with steep front toward an SPD installed at the far end of a branch circuit cable could require such a high voltage that the connections at the near end of the cable will flashover, limiting the stress applied to the far-end SPD, Tests and numerical modeling were performed to support this thesis, The results of real-world measurements and modeling, presented in the paper, are in good agreement and validate each other, From that point on, the model allows parametric variations of cable length and surge current amplitude and waveform, of which several examples are presented. C1 NIST,GAITHERSBURG,MD 20899. RP Mansoor, A (reprint author), POWER ELECT APPLICAT CTR,KNOXVILLE,TN 37932, USA. NR 13 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD JUL PY 1997 VL 12 IS 3 BP 1176 EP 1183 DI 10.1109/61.636937 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA XG987 UT WOS:A1997XG98700015 ER PT J AU Thacker, WC Lewandowicz, R AF Thacker, WC Lewandowicz, R TI A comparison of low-dimensional representations of sea-surface temperature anomalies in the North Atlantic SO INTERNATIONAL JOURNAL OF CLIMATOLOGY LA English DT Article DE North Atlantic Ocean; sea-surface temperatures; local variables; regional indices; covariance-matrix principal components; correlation-matrix principal components; skill; predictor selection ID PREDICTION; PREDICTABILITY; OCEAN; ENSO AB Correlation-matrix principal components of North Atlantic sea-surface temperature anomalies for the interval 1950-1970 account for the anomalous variability observed during the interval 1972-1992 better than do similar numbers of covariance-matrix principal components, regional averages, or carefully selected local anomalies. When drift in the seasonal cycle is taken into account, local anomalies for 127 6 degrees x 4 degrees longitude-by-latitude North Atlantic cells could be recovered with an average skill as high as 0.79. Surprisingly, skill increased monotonically with increasing numbers of principal components, and the maximum value was not obtained until 62 were used to characterize the field. Clearly, far more principal components carry useful information about local details than has been previously suspected. (C) 1997 by the Royal Meteorological Society. C1 COOPERAT INST MARINE & ATMOSPHER STUDIES,MIAMI,FL 33149. RP Thacker, WC (reprint author), NOAA,ATLANTIC OCEANOG & METEOROL LAB,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Thacker, Carlisle/I-3813-2013 OI Thacker, Carlisle/0000-0002-9285-8826 NR 21 TC 3 Z9 3 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0899-8418 J9 INT J CLIMATOL JI Int. J. Climatol. PD JUL PY 1997 VL 17 IS 9 BP 953 EP 967 DI 10.1002/(SICI)1097-0088(199707)17:9<953::AID-JOC169>3.0.CO;2-7 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XN618 UT WOS:A1997XN61800003 ER PT J AU Steiner, PJ Kelly, JR Giuseppetti, AA AF Steiner, PJ Kelly, JR Giuseppetti, AA TI Compatibility of ceramic-ceramic systems for fixed prosthodontics SO INTERNATIONAL JOURNAL OF PROSTHODONTICS LA English DT Article ID DENTAL PORCELAINS; LEUCITE AB study evaluated dilatometric data for predicting ceramic-ceramic compatibility for porcelains fired on central incisor copings (n = 72) of high expansion colored IPS-Empress porcelain. Nine body porcelains (leucite 0 wt% to 51 wt%) were each fired onto eight copings. Cracks were detected at 10 x magnification using transilluminating light. Failure was defined as the presence of at least one crack and probability of failure (P-f) as the ratio of failed to total crowns. Thermal contraction coefficients (alpha) were determined using four bars of each porcelain following the protocol of ISO 9693. Absolute differences in thermal contraction, \Delta alpha\, between core and lest porcelains were plotted against P-f and curve fit. Significant differences in ct were found among the porcelains tested (ANOVA, 95% Tukey); the a values ranged from 7.92 to 17.83 x 10(-6)/degrees C; P-f ranged from 0 to 1. Compatible porcelains (no cracks during any firing of all eight crowns) had \Delta alpha\ values less than 1 x 10(-6)/degrees C. Absolute values (\Delta alpha\) were surprisingly predictive of P-f given the very different cooling rates (dilatometry versus dental lab) and the relatively complex crown shape. Standard dilatometry may be useful for predicting the compatibility oi ceramic-ceramic-systems. Three porcelains, IPS-Empress dentin, Duceram, and Will-Ceram were successfully used for veneering IFS Empress cores. C1 NIST, GAITHERSBURG, MD 20899 USA. NATL NAVAL MED CTR, BETHESDA, MD USA. NR 10 TC 23 Z9 29 U1 0 U2 1 PU QUINTESSENCE PUBL CO INC PI CAROL STREAM PA 551 KIMBERLY DR, CAROL STREAM, IL 60188-1881 SN 0893-2174 J9 INT J PROSTHODONT JI Int. J. Prosthodont. PD JUL-AUG PY 1997 VL 10 IS 4 BP 375 EP 380 PG 6 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA XN376 UT WOS:A1997XN37600010 PM 9484048 ER PT J AU Hanley, HJM AF Hanley, HJM TI Particle dispersion in a gas SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE atmospheric pollution; diffusion coefficients; kinetic theory; nonequilibrium thermodynamics; particulate matter, quasi-lorentz model; thermal diffusion factor AB The dispersion mechanism of particles in a gas is discussed from the viewpoint of nonequilibrium thermodynamics and kinetic theory. A heuristic equation, based on the quasi-lorentz model developed by Mason and other workers, for the particle velocity in the presence of a gradient of pressure and temperature is proposed for all values of a parameter s, where a is defined as the ratio of the particle radius r to a multiple of the mean free path, lambda, of the gas medium. A schematic calculation demonstrates the conditions under which molecular diffusion could play a role in a realistic atmospheric pollution problem. RP Hanley, HJM (reprint author), NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,325 BROADWAY,BOULDER,CO 80303, USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD JUL PY 1997 VL 18 IS 4 BP 947 EP 955 DI 10.1007/BF02575240 PG 9 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA XQ594 UT WOS:A1997XQ59400009 ER PT J AU Tobias, DJ Tu, K Klein, ML AF Tobias, DJ Tu, K Klein, ML TI Assessment of all-atom potentials for modeling membranes: molecular dynamics simulations of solid and liquid alkanes and crystals of phospholipid fragments SO JOURNAL DE CHIMIE PHYSIQUE ET DE PHYSICO-CHIMIE BIOLOGIQUE LA English DT Article; Proceedings Paper CT CECAM Meeting on Potential Functions for Simulation of Biomolecular Systems CY SEP 23-25, 1996 CL LYON, FRANCE SP CECAM DE molecular dynamics; energy functions; membranes ID X-RAY-DIFFRACTION; CONSTANT-PRESSURE; N-OCTANE; BUTANE; CONFORMATION; TEMPERATURE; ENERGY; PHASE AB We present and evaluate the performance of an all-atom hydrocarbon potential for use in computer simulations of lipids. The performance is judged by comparing the results of constant pressure and temperature molecular dynamics simulations to experimental data for normal alkanes: solid octane and tricosane, and liquid butane, octane, tetradecane, and eicosane. The model exhibits good overall agreement with experimentally determined crystal structures, densities, energies, and diffusion constants, although some detailed aspects of the Liquid structure and conformational equilibria are not quantitatively reproduced. We have also checked the performance of four different all-atom models for the polar moeities of phospholipid molecules by constant pressure molecular dynamics simulations of crystals of phospholipid fragments: glycerylphosphorylcholine (GPC), cyclopentylphosphorylcholine mono hydrate (CPPC), and dilauroylglycerol (DLG). Simulations of GPC and CPPC showed that recent modifications to the phosphate parameters significantly improved the performance of the CHARMM 22 potential. The results obtained using two potentials based on the work of Stouch et al. reproduced all of the crystal structures quite well. C1 UNIV PENN,DEPT CHEM,CTR MOL MODELING,PHILADELPHIA,PA 19104. NATL INST STAND & TECHNOL,CTR NEUTRON RES,GAITHERSBURG,MD 20899. RI Tobias, Douglas/B-6799-2015 NR 45 TC 33 Z9 33 U1 0 U2 16 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 141 RUE JAVEL, 75747 PARIS, FRANCE SN 0021-7689 J9 J CHIM PHYS PCB JI J. Chim. Phys.-Chim. Biol. PD JUL-AUG PY 1997 VL 94 IS 7-8 BP 1482 EP 1502 PG 21 WC Biochemistry & Molecular Biology; Chemistry, Physical SC Biochemistry & Molecular Biology; Chemistry GA XQ688 UT WOS:A1997XQ68800010 ER PT J AU Straka, JM Rasmussen, EN AF Straka, JM Rasmussen, EN TI Toward improving microphysical parameterizations of conversion precesses SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID NUMERICAL-SIMULATION; MODEL; CONVECTION; STORMS; CLOUD AB Prognostic equations are proposed for use in gridpoint models for the purpose of providing Lagrangian information without the need for computing Lagrangian trajectories. The information provided by the proposed methods might lead to improved representations of microphysical conversion processes. For Example, the proposed methods could help improve the timing and location of the onset of precipitation in cloud models. C1 NATL SEVERE STORMS LAB,NORMAN,OK 73069. RP Straka, JM (reprint author), UNIV OKLAHOMA,ENERGY CTR,SCH METEOROL,100 E BOYD ST,NORMAN,OK 73019, USA. NR 20 TC 12 Z9 12 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUL PY 1997 VL 36 IS 7 BP 896 EP 902 DI 10.1175/1520-0450(1997)036<0896:TIMPOC>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XJ832 UT WOS:A1997XJ83200005 ER PT J AU DiRuggiero, J Santangelo, N Nackerdien, Z Ravel, J Robb, FT AF DiRuggiero, J Santangelo, N Nackerdien, Z Ravel, J Robb, FT TI Repair of extensive ionizing-radiation DNA damage at 95 degrees C in the hyperthermophilic archaeon Pyrococcus furiosus SO JOURNAL OF BACTERIOLOGY LA English DT Article ID BACTERIUM DEINOCOCCUS-RADIODURANS; CHROMOSOMAL PROTEIN; ARCHAEBACTERIUM; RESISTANCE; BREAKS; MC1 AB We investigated the capacity of the hyperthermophile Pyrococcus furiosus for DNA repair by measuring survival at high levels of Co-60 gamma-irradiation. The P. furiosus 2-Mb chromosome was fragmented: into pieces ranging from 500 kb to shorter than 30 kb at a dose of 2,500 Gy and was fully restored upon incubation at 95 degrees C. We suggest that recombination repair could be an extremely active repair mechanism in P. furiosus and that it might be an important determinant of survival of hyperthermophiles at high temperatures. C1 NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. RP DiRuggiero, J (reprint author), UNIV MARYLAND,CTR MARINE BIOTECHNOL,INST BIOTECHNOL,600 E LOMBARD ST,BALTIMORE,MD 21202, USA. RI Ravel, Jacques/D-2530-2009 NR 27 TC 78 Z9 81 U1 1 U2 5 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0021-9193 J9 J BACTERIOL JI J. Bacteriol. PD JUL PY 1997 VL 179 IS 14 BP 4643 EP 4645 PG 3 WC Microbiology SC Microbiology GA XM208 UT WOS:A1997XM20800028 PM 9226280 ER PT J AU Haywood, JM Roberts, DL Slingo, A Edwards, JM Shine, KP AF Haywood, JM Roberts, DL Slingo, A Edwards, JM Shine, KP TI General circulation model calculations of the direct radiative forcing by anthropogenic sulfate and fossil-fuel soot aerosol SO JOURNAL OF CLIMATE LA English DT Article ID GREENHOUSE GASES; ATMOSPHERIC AEROSOLS; CLIMATE MODEL; CLOUDS; SCHEME; CARBON; PARAMETRIZATION; ABSORPTION; PREDICTION; FORECAST AB A new radiation code within a general circulation model is used to assess the direct solar and thermal radiative forcing by sulfate aerosol of anthropogenic origin and soot aerosol from fossil-fuel burning. The radiative effects of different aerosol profiles, relative humidity parameterizations, chemical compositions, and internal and external mixtures of the two aerosol types are investigated. The contribution to the radiative forcing from cloudy sky regions is found to be negligible for sulfate aerosol: this is in contrast to recent studies where the cloudy sky contribution was estimated using a method in which the spatial correlation between cloud amount and sulfate burden was ignored. However, the radiative forcing due to fossil-fuel soot aerosol is enhanced in cloudy regions if soot aerosol exists within or above the cloud. The global solar radiative forcing due to sulfate aerosol is estimated to be -0.38 W m(-2) and the global thermal radiative forcing is estimated to be +0.01 W m(-2). The hemispheric mean radiative forcings vary by only about 10% for reasonable assumptions about the chemical form of the sulfate aerosol and the relative humidity dependence; the uncertainties in the aerosol loading are far more significant. If a soot/sulfate mass ratio of 0.075 is assumed, then the global solar radiative forcing weakens to -0.18 W m(-2) far an external mixture and weakens further for an internal mixture. Additionally, the spatial distribution of the radiative forcing shows strong negative/positive forcing contrasts that may influence the dynamical response of the atmosphere. Although these results are extremely sensitive to the adopted soot/sulfate ratio and the assumed vertical profile, they indicate that fossil fuel soot aerosol map exert a nonnegligible radiative forcing and emphasize the need to consider each anthropogenic aerosol species. C1 UK METEOROL OFF,HADLEY CTR CLIMATE PREDICT & RES,BRACKNELL,BERKS,ENGLAND. UNIV READING,DEPT METEOROL,READING,BERKS,ENGLAND. RP Haywood, JM (reprint author), PRINCETON UNIV,NOAA,GFDL,ATMOSPHER & OCEAN SCI PROGRAM,FORRESTAL CAMPUS,ROUTE 1,PRINCETON,NJ 08542, USA. RI Shine, Keith/D-9093-2012 OI Shine, Keith/0000-0003-2672-9978 NR 58 TC 180 Z9 193 U1 1 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1997 VL 10 IS 7 BP 1562 EP 1577 DI 10.1175/1520-0442(1997)010<1562:GCMCOT>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XP278 UT WOS:A1997XP27800006 ER PT J AU Koster, RD Milly, PCD AF Koster, RD Milly, PCD TI The interplay between transpiration and runoff formulations in land surface schemes used with atmospheric models SO JOURNAL OF CLIMATE LA English DT Article ID SOIL-MOISTURE; PARAMETERIZATION; BIOSPHERE AB The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) has shown that different land surface models (LSMs) driven by the same meteorological forcing can produce markedly different surface energy and water budgets, even when certain critical aspects of the LSMs (vegetation cover, albedo, turbulent drag coefficient, and snowcover) are carefully controlled. To help explain these differences, the authors devised a monthly water balance model that successfully reproduces the annual and seasonal water balances of the different PILPS schemes. Analysis of this model leads to the identification of two quantities that characterize an LSM's formulation of soil water balance dynamics: 1) the efficiency of the soil's evaporation sink integrated over the active soil moisture range, and 2) the fraction of this range over which runoff is generated. Regardless of the LSM's complexity, the combination of these two derived parameters with rates of interception loss, potential evaporation, and precipitation provides a reasonable estimate for the LSM's simulated annual water balance. The two derived parameters shed light on how evaporation and runoff formulations interact in an LSM, and the analysis as a whole underscores the need for compatibility in these formulations. C1 US GEOL SURVEY, GEOPHYS FLUID DYNAM LAB, NOAA, PRINCETON, NJ USA. RP Koster, RD (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HYDROL SCI BRANCH, LAB HYDROSPHER PROC, CODE 974, GREENBELT, MD 20771 USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 27 TC 198 Z9 207 U1 3 U2 10 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 JUL PY 1997 VL 10 IS 7 BP 1578 EP 1591 DI 10.1175/1520-0442(1997)010<1578:TIBTAR>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XP278 UT WOS:A1997XP27800007 ER PT J AU Gaffen, DJ Rosen, RD Salstein, DA Boyle, JS AF Gaffen, DJ Rosen, RD Salstein, DA Boyle, JS TI Evaluation of tropospheric water vapor simulations from the atmospheric model intercomparison project SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; HORIZONTAL RESOLUTION; SURFACE-TEMPERATURE; PRECIPITABLE WATER; CLIMATE SIMULATION; SEASONAL-VARIATION; ECMWF MODEL; PARAMETERIZATION; SENSITIVITY; SCHEME AB Simulations of humidity from 28 general circulation models for the period 1979-88 from the Atmospheric Model Intercomparison Project are compared with observations from radiosondes over North America and the globe and with satellite microwave observations over the Pacific basin. The simulations of decadal mean values of precipitable water (W) integrated over each of these regions tend to be less moist than the real atmosphere in all three cases; the median model values are approximately 5% less than the observed values. The spread among the simulations is larger over regions of high terrain, which suggests that differences in methods of resolving topographic features are important. The mean elevation of the North American continent is substantially higher in the models than is observed, which may contribute to the overall dry bias of the models over that area. The authors do not find a clear association between the mean topography of a model and its mean W simulation, however, which suggests that the bias over land is not purely a matter of orography. The seasonal cycle of W is reasonably well simulated by the models, although over North America they have a tendency to become moister more quickly in the spring than is observed. The interannual component of the variability of W is nor well captured by the models over North America. Globally, the simulated W values show a signal correlated with the Southern Oscillation index but the observations do not. This discrepancy may be related to deficiencies in the radiosonde network, which does not sample the tropical ocean regions well. Overall, the interannual variability of W as well as its climatology and mean seasonal cycle, are better described by the median of the 28 simulations than by individual members of the ensemble. Tests to learn whether simulated precipitable water, evaporation, and precipitation values may be related to aspects of model formulation yield few clear signals, although the authors find, for example, a tendency for the few models that predict boundary layer depth to have large values of evaporation and precipitation. Controlled experiments, in which aspects of model architecture are systematically varied within individual models, may be necessary to elucidate whether and how model characteristics influence simulations. C1 ATMOSPHER & ENVIRONM RES INC,CAMBRIDGE,MA 02139. LAWRENCE LIVERMORE NATL LAB,PROGRAM CLIMATE MODEL DIAG & INTERCOMPARISON,LIVERMORE,CA. RP Gaffen, DJ (reprint author), NOAA,REAR,ENVIRONM RES LABS,AIR RESOURCES LAB,1315 E WEST HIGHWAY,SILVER SPRING,MD 20910, USA. NR 56 TC 17 Z9 17 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1997 VL 10 IS 7 BP 1648 EP 1661 DI 10.1175/1520-0442(1997)010<1648:EOTWVS>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XP278 UT WOS:A1997XP27800012 ER PT J AU Wilson, CL Blue, JL Omidvar, OM AF Wilson, CL Blue, JL Omidvar, OM TI Neurodynamics of learning and network performance SO JOURNAL OF ELECTRONIC IMAGING LA English DT Article AB A simple dynamic model of a neural network is presented. Using the dynamic model of a neural network, we improve the performance of a three-layer multilayer perceptron (MLP). The dynamic model of a MLP is used to make fundamental changes in the network optimization strategy. These changes are: Neuron activation functions are used, which reduce the probability of singular Jacobians; Successive regularization is used to constrain the volume of the weight space being minimized; Boltzmann pruning is used to constrain the dimension of the weight space; and prior class probabilities are used to normalize all error calculations, so that statistically significant samples of rare but important classes can be included without distortion of the error surface. All four of these changes are made in the inner loop of a conjugate gradient optimization iteration and are intended to simplify the training dynamics of the optimization. On handprinted digits and fingerprint classification problems, these modifications improve error-reject performance by factors between 2 and 4 and reduce network size by 40 to 60%. (C) 1997 SPIE and IS&T. C1 NIST, Adv Syst Div, Gaithersburg, MD 20899 USA. NIST, Appl & Computat Math Div, Gaithersburg, MD 20899 USA. Univ Dist Columbia, Dept Comp Sci, Washington, DC 20009 USA. RP Wilson, CL (reprint author), NIST, Adv Syst Div, Gaithersburg, MD 20899 USA. NR 26 TC 1 Z9 1 U1 0 U2 0 PU I S & T - SOC IMAGING SCIENCE TECHNOLOGY PI SPRINGFIELD PA 7003 KILWORTH LANE, SPRINGFIELD, VA 22151 USA SN 1017-9909 J9 J ELECTRON IMAGING JI J. Electron. Imaging PD JUL PY 1997 VL 6 IS 3 BP 379 EP 385 DI 10.1117/12.272656 PG 7 WC Engineering, Electrical & Electronic; Optics; Imaging Science & Photographic Technology SC Engineering; Optics; Imaging Science & Photographic Technology GA ZY366 UT WOS:000074613600014 ER PT J AU Huang, HN Fergen, RE Proni, JR Tsai, JJ AF Huang, HN Fergen, RE Proni, JR Tsai, JJ TI Probabilistic analysis of ocean outfall mixing zones - Closure SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Editorial Material C1 NOAA,ATLANTIC OCEANOG & METEOROL LAB,DIV OCEAN ACOUST,MIAMI,FL 33149. RP Huang, HN (reprint author), HAZEN & SAWYER PC,4011 W CHASE BLVD,RALEIGH,NC 27607, USA. NR 1 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 SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD JUL PY 1997 VL 123 IS 7 BP 725 EP 726 DI 10.1061/(ASCE)0733-9372(1997)123:7(725) PG 2 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA XF801 UT WOS:A1997XF80100021 ER PT J AU Gillette, D AF Gillette, D TI Soil derived dust as a source of silica: Aerosol properties, emissions, deposition, and transport SO JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY LA English DT Article DE aerosol; composition; dust; emission; mineralogy; size-distribution ID WIND EROSION AB Quartz is art abundant mineral in wind generated dust throughout the United States. Of the 18.9 million tons of particles smaller than 10 mu m (PM10) dust emitted into the atmosphere by the wind, a significant fraction is silica. Transport of some of this silica to populated areas is possible. RP Gillette, D (reprint author), NOAA,AIR RESOURCES LAB,ATMOSPHER MODELING SCI DIV,MD-81,RES TRIANGLE PK,NC 27711, USA. NR 17 TC 6 Z9 7 U1 0 U2 1 PU PRINCETON SCIENTIFIC PUBL INC PI PRINCETON PA PO BOX 2155, PRINCETON, NJ 08543 SN 1053-4245 J9 J EXPO ANAL ENV EPID JI J. Expo. Anal. Environ. Epidemiol. PD JUL-SEP PY 1997 VL 7 IS 3 BP 303 EP 311 PG 9 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA XM155 UT WOS:A1997XM15500005 PM 9246593 ER PT J AU Canino, MF AF Canino, MF TI Nucleic acid contents and growth of first-feeding walleye pollock larvae in response to prey densities typical of sub-Arctic ecosystems SO JOURNAL OF FISH BIOLOGY LA English DT Article DE fish larvae; walleye pollock; nucleic acids; protein; growth ID RNA-DNA RATIO; MARINE FISH LARVAE; COD GADUS-MORHUA; THERAGRA-CHALCOGRAMMA PALLAS; PLAICE PLEURONECTES-PLATESSA; HERRING CLUPEA-HARENGUS; NUTRITIONAL CONDITION; RNA/DNA RATIOS; FOOD AVAILABILITY; BIOCHEMICAL-COMPOSITION AB The growth, nucleic acid and protein contents of walleye pollock Theragra chalcogramma larvae reared at prey densities of 10, 30, 50, and 500 prey l(-1) were measured for the first 9 days after the feeding initiation at 6 degrees C. Incremental growth rates of larvae (mm day(-1)) were low and Variable for the first 7 days after feeding initiation. Growth rates and rates of RNA, DNA, and protein accumulation by larvae reared at 500 prey l(-1) were positive while those of larvae reared at the lower prey levels did not differ significantly from zero. The RNA/DNA ratio was variable and exhibited no significant trend among food treatments. Estimates of instantaneous protein growth rates ranged from -6.7 to 13.2% day(-1) at food densities of 10 and 500 prey l(-1), respectively, and were moderately correlated with larval RNA/DNA ratios (r=0.628). The results suggest that in situ protein growth rates of first-feeding pollock larvae may be influenced by prey fields within the range of ambient food densities reported for sub-Arctic ecosystems. (C) 1997 The Fisheries Society of the British Isles. RP Canino, MF (reprint author), NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,7600 SAND POINT WAY NE,BIN C15700,SEATTLE,WA 98115, USA. NR 43 TC 6 Z9 6 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JUL PY 1997 VL 51 IS 1 BP 41 EP 52 PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XJ861 UT WOS:A1997XJ86100005 ER PT J AU Dryer, M Wu, CC Smith, ZK AF Dryer, M Wu, CC Smith, ZK TI Three-dimensional MHD simulation of the April 14, 1994, interplanetary coronal mass ejection and its propagation to Earth and Ulysses SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article; Proceedings Paper CT Chapman Conference on Magnetic Storms CY FEB 12-16, 1996 CL CALIF INST TECHNOL, PROPULS LAB, PASADENA, CA HO CALIF INST TECHNOL, PROPULS LAB ID MAGNETIC CLOUD PROPAGATION; SOLAR-WIND; DYNAMICAL EVOLUTION; ECLIPTIC-PLANE; DISTURBANCES; TEMPERATURE; HELIOSPHERE; STREAMER AB A three-dimensional (3-D), time-dependent, magnetohydrodynamic (MHD) model is used to simulate the interplanetary propagation of a disturbance that started in the low corona via the destabilization of a southern hemisphere helmet-streamer on April 14, 1994. A severe geomagnetic storm occurred at Earth, and a forward-reverse shock structure was detected at Ulysses (3.2 AU) at E30 degrees S60 degrees. The model is initiated at 18Rs (where Rs is the solar radius, 6.95 x 10(5) km) within the supersonic and super-Alfvenic region of the solar wind; hence no consideration is given to the disturbance's evolution from similar to 1Rs to 18Rs. We refer to the interplanetary disturbance as an interplanetary/coronal mass ejection (ICME) to indicate that it may be relevant to what has been referred to in the literature as a CME but is not related to the flux rope or magnetic cloud that has also received much attention. We find that the 3-D MHD model, with a simple pressure pulse (suggested by Yohkoh soft Xray observations), provides a satisfactory comparison with the SSC timing at Earth and the Ulysses observations. C1 NATL CENT UNIV, INST SPACE SCI, CHUNGLI, TAIWAN. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO USA. RP Dryer, M (reprint author), NOAA, SPACE ENVIRONM CTR, BOULDER, CO 80303 USA. RI xue, yansheng/A-9712-2012 NR 40 TC 19 Z9 21 U1 0 U2 1 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 JUL 1 PY 1997 VL 102 IS A7 BP 14065 EP 14074 DI 10.1029/97JA00872 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XJ204 UT WOS:A1997XJ20400005 ER PT J AU Araki, T Fujitani, S Emoto, M Yumoto, K Shiokawa, K Ichinose, T Luehr, H Orr, D Milling, DK Singer, H Rostoker, G Tsunomura, S Yamada, Y Liu, CF AF Araki, T Fujitani, S Emoto, M Yumoto, K Shiokawa, K Ichinose, T Luehr, H Orr, D Milling, DK Singer, H Rostoker, G Tsunomura, S Yamada, Y Liu, CF TI Anomalous sudden commencement on March 24, 1994 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article; Proceedings Paper CT Chapman Conference on Magnetic Storms CY FEB 12-16, 1996 CL CALIF INST TECHNOL, PROPULS LAB, PASADENA, CA HO CALIF INST TECHNOL, PROPULS LAB ID DYNAMIC PRESSURE CHANGES; ELECTRON-DRIFT ECHOES; INNER MAGNETOSPHERE; MAGNETIC-FIELD; ULF WAVES; IONOSPHERE; INJECTION; EQUATOR AB An anomalous geomagnetic sudden commencement (SC) occurred on March 24, 1991. It is characterized by an exceptionally large and sharp impulse observed in its initial part along the noon meridian in middle and low latitudes. The analysis of the SC was made by using high time resolution digital data from the 210 degrees Meridian Magnetometer Chain in the west Pacific, Sub-Auroral Magnetometer Network (SAMNET) in the United Kingdom and southern Scandinavia, the EISCAT Magnetometer Cross in northern Scandinavia and Svalbard, and Canopus in Canada together with other ground and satellite (GOES 6, GOES 7, CRRES, and GMS) data. The results of the analysis suggest that the pulse observed at lower-latitude ground stations was caused by the propagation of a strong magnetospheric compression of short duration (less than 1 min) which has never been observed before this event. The HF Doppler observation in Kyoto near local noon seems to be consistent with existence of the bipolar electric field associated with the propagating compressional magnetic pulse. The SAMNET stations and CRRES in the early morning also detected positive pulses which delays 30-50 s from the pulses in noon sector, Although the delay in the peak time of the pulse observed on the ground is consistent with ionospheric hydromagnetic wave propagation from the dayside to the nightside with finite speed, the initial onset time of the pulse on the ground was almost simultaneous everywhere suggesting the existence of an ''almost instantaneous'' propagation mode below the ionosphere. C1 DOSHISHA UNIV,DEPT ELECT,KYOTO 602,JAPAN. CHINESE ACAD SCI,INST GEOPHYS,BEIJING,PEOPLES R CHINA. TECH UNIV CAROLO WILHELMINA BRAUNSCHWEIG,INST GEOPHYS & METEOROL,D-38106 BRAUNSCHWEIG,GERMANY. UNIV YORK,DEPT PHYS,YORK YO1 5DD,N YORKSHIRE,ENGLAND. UNIV ALBERTA,DEPT PHYS,EDMONTON,AB T6G 2J1,CANADA. NAGOYA UNIV,SOLAR TERR ENVIRONM LAB,TOYOKAWA 442,JAPAN. NOAA,SPACE ENVIRONM LAB,BOULDER,CO 80303. KAKIOKA GEOMAGNET OBSERV,YASATO,IBARAGI 31501,JAPAN. RP Araki, T (reprint author), KYOTO UNIV,DEPT GEOPHYS,KYOTO 606,JAPAN. NR 35 TC 53 Z9 53 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1997 VL 102 IS A7 BP 14075 EP 14086 DI 10.1029/96JA03637 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XJ204 UT WOS:A1997XJ20400006 ER PT J AU Baker, DN Li, X Turner, N Allen, JH Bargatze, LF Blake, JB Sheldon, RB Spence, HE Belian, RD Reeves, GD Kanekal, SG Klecker, B Lepping, RP Ogilvie, K Mewaldt, RA Onsager, T Singer, HJ Rostoker, G AF Baker, DN Li, X Turner, N Allen, JH Bargatze, LF Blake, JB Sheldon, RB Spence, HE Belian, RD Reeves, GD Kanekal, SG Klecker, B Lepping, RP Ogilvie, K Mewaldt, RA Onsager, T Singer, HJ Rostoker, G TI Recurrent geomagnetic storms and relativistic electron enhancements in the outer magnetosphere: ISTP coordinated measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article; Proceedings Paper CT Chapman Conference on Magnetic Storms CY FEB 12-16, 1996 CL CALIF INST TECHNOL, PROPULS LAB, PASADENA, CA HO CALIF INST TECHNOL, PROPULS LAB ID SOLAR; SPACECRAFT; TELESCOPE; PARTICLE; SAMPEX AB New, coordinated measurements from the International Solar-Terrestrial Physics (ISTP) constellation of spacecraft are presented to show the causes and effects of recurrent geomagnetic activity during recent solar minimum conditions. It is found using WIND and POLAR data that even for modest geomagnetic storms, relativistic electron fluxes are strongly and rapidly enhanced within the outer radiation zone of the Earth's magnetosphere. Solar wind data are utilized to identify the drivers of magnetospheric acceleration processes. Yohkoh solar soft X-ray data are also used to identify the solar coronal holes that produce the high-speed solar wind streams which, in turn, cause the recurrent geomagnetic activity. It is concluded that even during extremely quiet solar conditions (sunspot minimum) there are discernible coronal holes and resultant solar wind streams which can produce intense magnetospheric particle acceleration. As a practical consequence of this Sun-Earth connection, it is noted that a long-lasting E>1MeV electron event in late March 1996 appears to have contributed significantly to a major spacecraft (Anik E1) operational failure. C1 NOAA,NATL GEOPHYS DATA CTR,SCOSTEP SECRETARIAT,BOULDER,CO 80302. MONTANA STATE UNIV,DEPT PHYS,BOZEMAN,MT 59717. AEROSP CORP,LOS ANGELES,CA 90009. BOSTON UNIV,CTR SPACE PHYS,BOSTON,MA 02215. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. MAX PLANCK INST PHYS & ASTROPHYS,D-8046 GARCHING,GERMANY. CALTECH,PASADENA,CA 91125. NOAA,RESE,SPACE ENVIRONM CTR,BOULDER,CO 80302. UNIV ALBERTA,DEPT PHYS,EDMONTON,AB,CANADA. RP Baker, DN (reprint author), UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,CAMPUS BOX 590,BOULDER,CO 80303, USA. RI Spence, Harlan/A-1942-2011; Reeves, Geoffrey/E-8101-2011; OI Reeves, Geoffrey/0000-0002-7985-8098; Turner, Niescja/0000-0002-3280-4260 NR 24 TC 103 Z9 104 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1997 VL 102 IS A7 BP 14141 EP 14148 DI 10.1029/97JA00565 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XJ204 UT WOS:A1997XJ20400011 ER PT J AU Codrescu, MV FullerRowell, TJ Kutiev, IS AF Codrescu, MV FullerRowell, TJ Kutiev, IS TI Modeling the F layer during specific geomagnetic storms SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article; Proceedings Paper CT Chapman Conference on Magnetic Storms CY FEB 12-16, 1996 CL CALIF INST TECHNOL, PROPULS LAB, PASADENA, CA HO CALIF INST TECHNOL, PROPULS LAB ID THERMOSPHERIC COMPOSITION; IONOSPHERE; EQUATION; F2-LAYER; GAS AB Important progress has been made recently in developing an understanding of the effects of geomagnetic storms in the thermosphere and ionosphere. Numerical simulations of theoretical storms with the coupled thermosphere ionosphere model (CTIM) have provided a better understanding of the dynamics of the upper atmosphere and have also permitted the identification of the processes responsible for global storm effects at highlatitude and midlatitude. The theory developed based on the model simulations can explain most of the apparent coherence of local time and seasonal dependencies and the apparent randomness in the longitudinal response of the global ionosphere, uncovered through statistical analysis of storm observations. A true test of the model and the theory is their ability to predict the large-scale distribution of storm effects for specific storms. In this paper, CTIM simulation results for the December 79, 1982, period are presented. We compare model results with DE 2 temperature and plasma density data. We also compare modeled electron densities with ionosonde data from several sectors in both hemispheres. The global characteristics of the response are reproduced by the model, and we are able to explain the pronounced longitude differences in the summer hemisphere. The Australian sector passes through midnight during the main driven phase of the storm and experiences the largest energy input and the largest neutral composition changes. The deepest ionospheric negative phase seen in ionosonde data is over Australia and is consistent with this interpretation. Given the large uncertainties in our knowledge of the magnitude and spatial distribution of energy input during a particular storm, predicting local changes is still a challenge. RP Codrescu, MV (reprint author), UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,SPACE ENVIRONM CTR,R E SE,325 BROADWAY,BOULDER,CO 80303, USA. RI Kutiev, Ivan/J-9753-2014 NR 27 TC 43 Z9 44 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1997 VL 102 IS A7 BP 14315 EP 14329 DI 10.1029/97JA00638 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XJ204 UT WOS:A1997XJ20400027 ER PT J AU Lu, G Siscoe, GL Richmond, AD Pulkkinen, TI Tsyganenko, NA Singer, HJ Emery, BA AF Lu, G Siscoe, GL Richmond, AD Pulkkinen, TI Tsyganenko, NA Singer, HJ Emery, BA TI Mapping of the ionospheric field-aligned currents to the equatorial magnetosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HIGH-LATITUDE IONOSPHERE; MAGNETIC-FIELD; ELECTRODYNAMIC FEATURES; LOCALIZED OBSERVATIONS; SYNCHRONOUS ORBIT; AURORAL IMAGES; SUBSTORMS; MODEL; SIGNATURES; CONDUCTANCES AB The assimilative mapping of ionospheric electrodynamics (AMIE)-derived ionospheric field-aligned current patterns during the ninth Coordinated Data Analysis Workshop substorm event have been mapped to the magnetospheric equatorial plane, using the data-based magnetospheric magnetic field model [Tsyganenko, 1995]. We find that at the onset of the substorm expansion phase, a pair of field-aligned currents emerges about 8 R-E tailward of the Earth, near the x axis. This pair of field-aligned currents is consistent with the substorm current wedge model; it lines up in the east-west direction across the near-Earth tail current and has the sense of the nightside region 1 current, i.e., flowing into the ionosphere on the east side and out of the, ionosphere on the west side. The ionospheric counterpart of the substorm wedge currents in the midnight sector, on the other hand, has a northeast-to-southwest alignment. During the expansion phase, the substorm wedge currents intensify and expand in spatial size; however, their peaks remain nearly at the same location in the equatorial magnetosphere, about 8 R-E tailward from the Earth. We also find that the intensification of the substorm wedge currents during the expansion phase is accompanied by the intensification of the region 2-sense currents located closer to the Earth, and the boundary between the region 2 and substorm wedge currents lies around x = -6 R-E. C1 FINNISH METEOROL INST,DEPT GEOPHYS,FIN-00101 HELSINKI,FINLAND. NOAA,SPACE ENVIRONM CTR,BOULDER,CO 80303. BOSTON UNIV,CTR SPACE PHYS,BOSTON,MA 02215. NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX CORP,GREENBELT,MD 20771. RP Lu, G (reprint author), NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,3540 MITCHELL LANE,BOULDER,CO 80301, USA. RI Lu, Gang/A-6669-2011; Tsyganenko, Nikolai/J-7377-2012; Pulkkinen, Tuija/D-8403-2012 OI Tsyganenko, Nikolai/0000-0002-5938-1579; Pulkkinen, Tuija/0000-0002-6317-381X NR 32 TC 11 Z9 11 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1997 VL 102 IS A7 BP 14467 EP 14476 DI 10.1029/97JA00744 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XJ204 UT WOS:A1997XJ20400039 ER PT J AU Riley, P Gosling, JT Pizzo, VJ AF Riley, P Gosling, JT Pizzo, VJ TI A two-dimensional simulation of the radial and latitudinal evolution of a solar wind disturbance driven by a fast, high-pressure coronal mass ejection SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID REVERSE SHOCK PAIRS; INTERPLANETARY; ULYSSES; MHD AB Using a hydrodynamic simulation, we have studied the two-dimensional (symmetry in the azimuthal direction) evolution of a fast, high-pressure coronal mass ejection (CME) ejected into a solar wind with latitudinal variations similar to those observed by Ulysses. Specifically, the latitudinal structure of the ambient solar wind in the meridional plane is approximated by two zones: At low latitudes (< 20 degrees) the solar wind is slow and dense, while at higher latitudes the solar wind is fast and tenuous. The CME is introduced into this ambient wind as a bell-shaped pressure pulse in time, spanning from the equator to 45 degrees with a speed and temperature equal to that of the high-latitude solar wind. We find that such an ejection profile produces radically different disturbance profiles at low and high latitudes. In particular, the low-latitude portion of the ejecta material drives a highly asymmetric disturbance because of the relative difference in speed between the fast CME and slower ambient solar wind ahead. In contrast, the high-latitude portion of the same ejecta material drives a much more radially symmetric disturbance because the relative difference in pressure between the CME and ambient background plasma dominates the dynamics. The simulations reveal a number of other interesting features. First, there is significant distortion of the CME in the interplanetary medium. By similar to 1 AU the CME has effectively separated (in radius as well as latitude) into two pieces. The radial separation is due to the strong velocity shear between the slow and fast ambient solar wind. The latitudinal separation arises from pressure gradients associated with rarefaction regions that develop as the CME propagates outward. Second, there is significant poleward motion of the highest-latitude portion of the CME and its associated disturbance. The main body of the CME expands poleward by similar to 18 degrees, while the forward and reverse waves (produced by the overexpanding portion of the CME) propagate all the way to the pole. Third, the simulations shaw that the high-pressure region, which develops at low latitudes as the fast CME ploughs through the slow ambient solar wind, penetrates significantly (similar to 10 degrees) into the high-latitude fast solar wind. We compare the simulation results with a CME-driven interplanetary disturbance observed at both low and high latitudes and find that the simulation reproduces many of the essential features of the observations. C1 NOAA,SPACE ENVIRONM LAB,BOULDER,CO 80303. RP Riley, P (reprint author), LOS ALAMOS NATL LAB,SPACE & ATMOSPHER SCI GRP,POB 1663,NIS-1,MS D466,LOS ALAMOS,NM 87545, USA. NR 20 TC 66 Z9 66 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1997 VL 102 IS A7 BP 14677 EP 14685 DI 10.1029/97JA01131 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XJ204 UT WOS:A1997XJ20400055 ER PT J AU Feldman, A AF Feldman, A TI Thermal wave imaging of indented diamond coated WC SO JOURNAL OF MATERIALS RESEARCH LA English DT Article AB Photothermal radiometry has been used to obtain thermal wave images in the vicinity of indentations in WC-6% Ni coated with chemical vapor deposited (CVD) diamond. Features in the magnitude and phase of the thermal signal profile are consistent with a one-dimensional thermal wave theory that assumes (i) an air gap extending well beyond the visibly observable indented region, and (ii) a thermal resistance interface between the diamond film and the substrate over the entire coated surface. The theory allows us to estimate the air gap thickness, which decreases as the distance from the indented region increases. Air gap variations of tens of nanometers appear to be easily detectable. RP Feldman, A (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 20 TC 1 Z9 1 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUL PY 1997 VL 12 IS 7 BP 1911 EP 1916 DI 10.1557/JMR.1997.0261 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA XJ194 UT WOS:A1997XJ19400034 ER PT J AU Ilavsky, J Allen, AJ Long, GG Herman, H Berndt, CC AF Ilavsky, J Allen, AJ Long, GG Herman, H Berndt, CC TI Characterization of the closed porosity in plasma-sprayed alumina SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID ANGLE NEUTRON-SCATTERING; COATINGS AB The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry, water immersion methods, and small-angle neutron scattering. A comparison of the results shows that the intrusion techniques did not yield a full porous phase characterization. It has been found that while the amount of closed porosity was 1.4% (+/- 0.5%) of the sample volume, this volume accounted for only 60% of the total internal surface area. The smallest void diameter was found to be 10 nm. C1 SUNY STONY BROOK,DEPT MAT SCI & ENGN,STONY BROOK,NY 11794. RP Ilavsky, J (reprint author), NIST,GAITHERSBURG,MD 20899, USA. RI Ilavsky, Jan/D-4521-2013 OI Ilavsky, Jan/0000-0003-1982-8900 NR 19 TC 12 Z9 13 U1 0 U2 2 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD JUL 1 PY 1997 VL 32 IS 13 BP 3407 EP 3410 DI 10.1023/A:1018616632261 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA XJ843 UT WOS:A1997XJ84300009 ER PT J AU Ohashi, N Tsuura, M Hougen, JT Ernst, WE Rakowsky, S AF Ohashi, N Tsuura, M Hougen, JT Ernst, WE Rakowsky, S TI Effective rotation-pseudorotation Hamiltonian for X-3-type molecules: Application to the (B)over-tilde-(X)over-tilde transition of Na-3 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID SPECTROSCOPY; QUANTIZATION; NA3 AB 0A formalism has been developed for rotation-pseudorotation energy levels of X-3-type molecules in orbitally nondegenerate electronic states (so that Jahn-Teller complications are absent). The formalism includes electron spin, but excludes nuclear spin effects. Correlation diagrams are presented connecting rotational energy levels in the high-barrier asymmetric-rotor limit to those in the low-barrier free-rotor quasi-symmetric-top limit. By applying the formalism to the (B) over tilde state of Na-3, which exhibits nearly free pseudorotation, a global fit of 216 (B) over tilde (u = 1)-(X) over tilde transitions to 15 molecular parameters was carried out, leading to a satisfactory standard deviation of 0.012 cm(-1). (The lower (X) over tilde state was treated as a rigid asymmetric rotor.) The fit contains many j = 0 levels and some j = 1 levels, but only a few j = 2 and j = 3 levels, where j is the pseudorotation quantum number in the B state. Inclusion of traditional spin-rotation terms did not improve the fit, but a phenomenological term coupling electron spin to the pseudorotation angular momentum was able to account for the large spin splittings observed in j > 0 pseudorotational levels, Our ground state rotational constants are consistent with those determined by other workers from analysis of the (A) over tilde-(X) over tilde transition. (C) 1997 Academic Press. C1 NATL INST STAND & TECHNOL,OPT TECH DIV,GAITHERSBURG,MD 20899. PENN STATE UNIV,DEPT PHYS,UNIVERSITY PK,PA 16802. MAX PLANCK INST STROMUNGSFORSCH,D-37073 GOTTINGEN,GERMANY. RP Ohashi, N (reprint author), KANAZAWA UNIV,FAC SCI,DEPT PHYS,KANAZAWA,ISHIKAWA 92011,JAPAN. RI Ernst, Wolfgang E/B-3257-2016 OI Ernst, Wolfgang E/0000-0001-8849-5658 NR 15 TC 16 Z9 16 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUL PY 1997 VL 184 IS 1 BP 22 EP 34 DI 10.1006/jmsp.1997.7306 PG 13 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA XR122 UT WOS:A1997XR12200003 ER PT J AU Linnartz, H Zink, LR Evenson, KM AF Linnartz, H Zink, LR Evenson, KM TI The pure rotational spectra of (KrH+)-Kr-84 and (KrH+)-Kr-86 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID DIPOLE-MOMENT; SPECTROSCOPY; TRANSITIONS; IONS; XEH+; KRH+ AB Rotational absorption spectra of the krypton hydride ion in its ground electronic and vibrational state have been measured with tunable far-infrared radiation. These accurate frequency measurements determine the rotational constants B, D, and H, and yield transition frequencies accurate to 40 kHz (1 sigma). By combining the new results with the former microwave data on several isotopic forms of (KrD+)-Kr-x a Dunham analysis can be performed, yielding accurate information on the Born-Oppenheimer breakdown parameters. (C) 1997 Academic Press. C1 NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,BOULDER,CO 80303. RP Linnartz, H (reprint author), UNIV BASEL,INST PHYS CHEM,KLINGELBERGSTR 80,CH-4056 BASEL,SWITZERLAND. NR 15 TC 9 Z9 9 U1 1 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUL PY 1997 VL 184 IS 1 BP 56 EP 59 DI 10.1006/jmsp.1997.7297 PG 4 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA XR122 UT WOS:A1997XR12200006 ER PT J AU Domenech, JL Fraser, GT Walker, ARH Lafferty, WJ Suenram, RD AF Domenech, JL Fraser, GT Walker, ARH Lafferty, WJ Suenram, RD TI Infrared and microwave molecular-beam studies of N2O5 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID BANDS AB Rotational spectra of the P-r(0) and R-r(0) b-type subbands of N2O5 for both internal rotor states were recorded using a pulsed-nozzle Fourier-transform microwave spectrometer. The present measurements extend our previous results on N2O5 which were confined to the R-r(0), R-r(1), (r)Q(1), and P-r(1), b-type subbands due to limitations in the frequency coverage of the instrument. The present measurements provide new energy-level differences which give a nearly complete experimental picture of the K = 0, 1, and 2 energy levels. The measurements also support our previous picture of N2O5 as a C-2 symmetry molecule with facile geared internal rotation of the two equivalent NO2 groups. Infrared spectra of the 1246 cm(-1) nu(12), N-O stretching fundamental band of N2O5 were also recorded using a lead-salt diode-laser spectrometer and a slit-jet nozzle molecular-beam apparatus. The spectra reveal a complex resolved rotational structure which is at present unanalyzed. (C) 1997 Academic Press. C1 CSIC,INST ESTRUCTURA MAT,E-28006 MADRID,SPAIN. RP Domenech, JL (reprint author), NIST,OPT TECHNOL DIV,GAITHERSBURG,MD 20899, USA. RI Domenech, Jose/F-5561-2013; Hight Walker, Angela/C-3373-2009 OI Domenech, Jose/0000-0001-8629-2566; Hight Walker, Angela/0000-0003-1385-0672 NR 6 TC 5 Z9 5 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUL PY 1997 VL 184 IS 1 BP 172 EP 176 DI 10.1006/jmsp.1997.7323 PG 5 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA XR122 UT WOS:A1997XR12200022 ER PT J AU Williams, KL Sander, LC Wise, SA AF Williams, KL Sander, LC Wise, SA TI Comparison of liquid and super-critical fluid chromatography for the separation of enantiomers on chiral stationary phases SO JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS LA English DT Article DE liquid chromatography; supercritical fluid chromatography; chiral stationary phase; enantiomers ID SUPERCRITICAL CARBON-DIOXIDE; SUBCRITICAL FLUID; BETA-BLOCKERS; PACKED-COLUMNS; OPTICAL RESOLUTION; DRUG DEVELOPMENT; HPLC; SFC; DERIVATIVES; CELLULOSE AB Comparisons of liquid (LC) and supercritical fluid chromatography (SFC) were conducted using commercially available chiral stationary phases (CSPs) bearing three different types of chiral selectors. Chiral compounds of pharmaceutical and agricultural interest were used to probe advantages or limitations of SFC relative to LC for enantiomeric separations. Column equilibration and parameter optimization were generally accomplished more rapidly in SFC than in LC. Although improved resolution was often observed in SFC, analysis times were not always lower in SFC than in LC. In some instances, SFC provided separation capabilities not readily accessible in LC. (C) 1997 Elsevier Science B.V. RP Williams, KL (reprint author), NIST,DIV ANALYT CHEM,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 41 TC 46 Z9 46 U1 2 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0731-7085 J9 J PHARMACEUT BIOMED JI J. Pharm. Biomed. Anal. PD JUL PY 1997 VL 15 IS 11 BP 1789 EP 1799 DI 10.1016/S0731-7085(96)01970-X PG 11 WC Chemistry, Analytical; Pharmacology & Pharmacy SC Chemistry; Pharmacology & Pharmacy GA XP918 UT WOS:A1997XP91800021 PM 9260677 ER PT J AU Fernandez, DP Goodwin, ARH Lemmon, EW Sengers, JMHL Williams, RC AF Fernandez, DP Goodwin, ARH Lemmon, EW Sengers, JMHL Williams, RC TI A formulation for the static permittivity of water and steam at temperatures from 238 K to 873 K at pressures up to 1200 MPa, including derivatives and Debye-Huckel coefficients SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Review DE data correlation; Debye-Huckel coefficients; g-factor; ITS-90; static dielectric constant; static relative permittivity; steam; supercritical steam; supercooled water; water ID DIELECTRIC-CONSTANT; FUNDAMENTAL EQUATION; SUPERCOOLED WATER; CRITICAL REGION; LIQUID WATER; H2O; ELECTROLYTES; FREQUENCIES; BEHAVIOR; RANGE AB A new formulation is presented of the static relative permittivity or dielectric constant of water and steam, including supercooled and supercritical states, The range is from 238 K to 873 K, at pressures up to 1200 MPa. The formulation is based on the ITS-90 temperature scale. It correlates a selected set of data from a recently published collection of all experimental data. The set includes new data in the liquid water and the steam regions that have not been part of earlier correlations. The physical basis for the formulation is the so-called g-factor in the form proposed by Harris and Alder. An empirical 12-parameter form for the g-factor as a function of the independent variables temperature and density is used. For the conversion of experimental pressures to densities, the newest formulation of the equation of slate of water on the ITS-90, prepared by Wagner and Pruss, has been used. All experimental data are compared with the formulation. The reliability of the new formulation is assessed in all subregions. Comparisons with previous formulations are presented. Auxiliary dielectric-constant formulations as functions of temperature are included for the saturated vapor and liquid states. The pressure and temperature derivatives of the dielectric constant and the Debye-Huckel limiting-law slopes are calculated, their reliability is estimated, and they are compared with experimentally derived values and with previous correlations. All equations are given in this paper, along with short tables. An implementation of this formulation for the dielectric constant is available on disk [A. H. Harvey, A. P. Peskin, and S. A. Klein, NIST/ASME Steam Properties, NIST Standard Reference Database 10, Version 2.1, Standard Reference Data Program, NIST, Gaithersburg, MD (1997)]. (C) 1997 American Institute of Physics and American Chemical Society. C1 NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. COMIS NACL ENERGIA ATOM,DEPT QUIM REACTORES,RA-1429 BUENOS AIRES,DF,ARGENTINA. UNIV IDAHO,CTR APPL THERMODYNAM STUDIES,MOSCOW,ID 83844. NR 102 TC 251 Z9 254 U1 7 U2 37 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD JUL-AUG PY 1997 VL 26 IS 4 BP 1125 EP 1166 PG 42 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA XN550 UT WOS:A1997XN55000003 ER PT J AU Beletsky, D OConnor, WP Schwab, DJ Dietrich, DE AF Beletsky, D OConnor, WP Schwab, DJ Dietrich, DE TI Numerical simulation of internal Kelvin waves and coastal upwelling fronts SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SOUTHERN LAKE-MICHIGAN; ONTARIO; OCEAN; MODELS; CIRCULATION; CURRENTS AB Two three-dimensional primitive equation numerical ocean models are applied to the problem of internal Kelvin waves and coastal upwelling in the Great Lakes. One is the Princeton Ocean Model (POM) with a terrain-following (sigma) vertical coordinate, and the other is the Dietrich/Center for Air Sea Technology (DIECAST) model with constant z-level coordinates. The sigma coordinate system is particularly convenient for simulating coastal upwelling, while the z-level system might be better for representing abrupt topographic changes. The models are first tested with a stratified idealized circular lake 100 km in diameter and 100 m deep. Two bottom topographies are considered: a flat bottom and a parabolic depth profile. Three rectilinear horizontal grids are used: 5, 2.5, and 1.25 km. The POM was used with 13 vertical levels, while the DIECAST model was tested with both 13 and 29 vertical levels. The models are driven with an impulsive wind stress imitating the passage of a weather system. In the case of the Aar-bottom basin, the dynamical response to light wind forcing is a small amplitude internal Kelvin wave. For both models, the speed of the Kelvin wave in the model is somewhat less than the inviscid analytic solution wave speed. In the case of strong wind forcing, the thermocline breaks the surface (full upwelling) and a strong surface thermal front appears. After the wind ceases, the edges of this thermal front propagate cyclonically around the lake, quite similar to an internal Kelvin wave. In the case of parabolic bathymetry, Kelvin wave and thermal front propagation is modified by interaction with a topographic wave and a geostrophic circulation. In both models, higher horizontal resolution gives higher wave and frontal speeds. Horizontal resolution is much more critical in the full upwelling case than in the Kelvin wave case. Vertical resolution is not as critical. The models are also applied to Lake Michigan to determine the response to strong northerly winds causing upwelling along the eastern shore. The results are more complex than for the circular basin, but clearly show the characteristics of cyclonically propagating thermal fronts. The resulting northward warm front propagation along the eastern shore compares favorably with observations of temperature fluctuations at municipal water intakes after a storm, although the model frontal speed was less than the observed speed. C1 NOAA,GREAT LAKES ENVIRONM RES LAB,ERL,ANN ARBOR,MI 48105. UNIV MICHIGAN,COOPERAT INST LIMNOL & ECOSYST RES,ANN ARBOR,MI 48109. MISSISSIPPI STATE UNIV,CTR AIR SEA TECHNOL,STENNIS SPACE CTR,MS. RI Schwab, David/B-7498-2012; OI Beletsky, Dmitry/0000-0003-4532-0588 NR 46 TC 47 Z9 47 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUL PY 1997 VL 27 IS 7 BP 1197 EP 1215 DI 10.1175/1520-0485(1997)027<1197:NSOIKW>2.0.CO;2 PG 19 WC Oceanography SC Oceanography GA XM923 UT WOS:A1997XM92300002 ER PT J AU Williams, DF Hayden, LA Marks, RB AF Williams, DF Hayden, LA Marks, RB TI A complete multimode equivalent-circuit theory for electrical design SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE conductor current; conductor representation; conductor voltage; electromagnetic modes; impedance matrix; modal representation; multiconductor transmission line AB This work presents a complete equivalent-circuit theory for lossy multimode transmission lines. Its voltages and currents are based on general linear combinations of standard normalized modal voltages and currents. The theory includes new expressions for transmission line impedance matrices, symmetry and lossless conditions, source representations, and the thermal noise of passive multiports. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Williams, DF (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 28 TC 21 Z9 22 U1 2 U2 3 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD JUL-AUG PY 1997 VL 102 IS 4 BP 405 EP 423 DI 10.6028/jres.102.029 PG 19 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2818 UT WOS:000168726500001 PM 27805153 ER PT J AU Villarrubia, JS AF Villarrubia, JS TI Algorithms for scanned probe microscope image simulation, surface reconstruction, and tip estimation SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE algorithms; atomic force microscopy; blind reconstruction; dimensional metrology; image simulation; mathematical morphology; scanned probe microscopy; scanning tunneling microscopy; surface reconstruction; tip artifacts; tip estimation AB To the extent that tips are not perfectly sharp, images produced by scanned probe microscopies (SPM) such as atomic force microscopy and scanning tunneling microscopy are only approximations of the specimen surface, np-induced distortions are significant whenever the specimen contains features with aspect ratios comparable to the tip's. Treatment of the tip-surface interaction as a simple geometrical exclusion allows calculation of many quantities important for SPM dimensional metrology. Algorithms for many of these are provided here, including the following: (1) calculating an image given a specimen and a tip (dilation), (2) reconstructing the specimen surface given its image and the tip (erosion), (3) reconstructing the tip shape from the image of a known "tip characterizer" (erosion again), and (4) estimating the tip shape from an image of an unknown tip characterizer (blind reconstruction). Blind reconstruction, previously demonstrated only for simulated noiseless images, is here extended to images with noise or other experimental artifacts. The main body of the paper serves as a programmer's and user's guide. It includes theoretical background for all of the algorithms, detailed discussion of some algorithmic problems of interest to programmers, and practical recommendations for users. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Villarrubia, JS (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 41 TC 357 Z9 367 U1 7 U2 52 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD JUL-AUG PY 1997 VL 102 IS 4 BP 425 EP 454 DI 10.6028/jres.102.030 PG 30 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2818 UT WOS:000168726500002 PM 27805154 ER PT J AU Zimmerman, BE Colle, R AF Zimmerman, BE Colle, R TI Standardization of Ni-63 by 4 pi beta liquid scintillation spectrometry with H-3-standard efficiency tracing SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE beta-counting; CIEMAT/NIST Method; liquid scintillation; nickel-63; radioactivity; standards AB The low energy (E-beta max = 66.945 keV +/- 0.004 keV) beta -emitter Ni-63 has become increasingly important in the field of radionuclidic metrology. In addition to having a low beta -endpoint energy, the relatively long half-life (101.1 a +/- 1.4 a) makes it an appealing standard for such applications. This paper describes the recent preparation and calibration of a new solution Standard Reference Material of Ni-63, SRM 4226C, released by the National Institute of Standards and Technology. The massic activity C-A for these standards was determined using 4 pi beta liquid scintillation (LS) spectrometry with H-3-standard efficiency tracing using the CIEMAT/NIST method, and is certified as 50.53 kBq.g(-l) +/- 0.46 Bq.g(-1) at the reference time of 1200 EST August 15, 1995. The uncertainty given is the expanded (coverage factor k = 2 and thus a 2 standard deviation estimate) uncertainty based on the evaluation of 28 different uncertainty components. These components were evaluated on the basis of an exhaustive number (976) of LS counting measurements investigating over 15 variables. Through the study of these variables it was found that LS cocktail water mass fraction and ion concentration play important roles in cocktail stability and consistency of counting results. The results of all of these experiments are discussed. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Zimmerman, BE (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 21 TC 31 Z9 31 U1 0 U2 1 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD JUL-AUG PY 1997 VL 102 IS 4 BP 455 EP 477 DI 10.6028/jres.102.031 PG 23 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2818 UT WOS:000168726500003 PM 27805155 ER PT J AU Murthy, AV Tsai, BK Gibson, CE AF Murthy, AV Tsai, BK Gibson, CE TI Calibration of high heat flux sensors at NIST SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE absolute technique; calibration; heat flux; irradiance; radiation; sensor; transfer technique; uncertainties AB An ongoing program at the National Institute of Standards and Technology (NIST) is aimed at improving and standardizing heat-flux sensor calibration methods. The current calibration needs of U.S. science and industry exceed the current NIST capability of 40 kW/m(2) irradiance. In achieving this goal, as well as meeting lower-level non-radiative heat flux calibration needs of science and industry, three different types of calibration facilities currently are under development at NIST: convection, conduction, and radiation. This paper describes the research activities associated with the NIST Radiation Calibration Facility. Two different techniques, transfer and absolute, are presented. The transfer calibration technique employs a transfer standard calibrated with reference to a radiometric standard for calibrating the sensor; using a graphite tube blackbody. Plans for an absolute calibration facility include the use of a spherical blackbody and a cooled aperture and sensor-housing assembly to calibrate the sensors in a low convective environment. C1 Aerotech Inc, Hampton, VA 23666 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Murthy, AV (reprint author), Aerotech Inc, Hampton, VA 23666 USA. NR 15 TC 7 Z9 7 U1 4 U2 5 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD JUL-AUG PY 1997 VL 102 IS 4 BP 479 EP 488 DI 10.6028/jres.102.032 PG 10 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA V2818 UT WOS:000168726500004 PM 27805156 ER PT J AU Hackley, VA Paik, U Kim, BH Malghan, SG AF Hackley, VA Paik, U Kim, BH Malghan, SG TI Aqueous processing of sintered reaction-bonded silicon nitride .1. Dispersion properties of silicon powder SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID SUSPENSIONS AB An aqueous-based system (Si-Al2O3-Y2O3-Fe2O3) for processing sintered reaction-bonded silicon nitride (SRBSN) was investigated with an emphasis on chemical control of suspension component interactions. Chemical stability and dispersion properties of a commercial silicon powder were characterized using electroacoustic, adsorption isotherm, and rheological measurements. The interactions of silicon with nitriding agent, sintering aids, dispersants, and binder were considered. The effects of pH, electrolyte, aging, particle size, and solids loading were examined. The suspension properties of the silicon powder were influenced by the native oxide film and powder treatment history. The silicon-oxide composite particles exhibit dispersion behavior similar to silica, characterized by a negative surface potential above pH 2. A method to improve the dispersion and homogeneity of suspension components based on the use of quaternary amine dispersants is proposed. RP Hackley, VA (reprint author), NIST,MAT SCI & ENGN LAB,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 32 TC 54 Z9 54 U1 0 U2 8 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUL PY 1997 VL 80 IS 7 BP 1781 EP 1788 PG 8 WC Materials Science, Ceramics SC Materials Science GA XK874 UT WOS:A1997XK87400023 ER PT J AU Roads, J Chen, S Kanamitsu, M Juang, H AF Roads, J Chen, S Kanamitsu, M Juang, H TI GDAS's GCIP energy budgets SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NATIONAL-METEOROLOGICAL-CENTER; HYDROLOGIC-CYCLE; GLOBAL ANALYSES; MODEL; NMC; CLIMATE AB The National Centers for Environmental Prediction's operational global data assimilation system's (GDAS) atmospheric and surface thermodynamic energy cycles are presented for the Mississippi River basin where the Global Energy and Water Cycle Experiment Continental-Scale International project (GCIP) is under way, At the surface, during the winter, incoming solar radiation is balanced by longwave cooling. During the summer, latent and sensible cooling are equally important. In the atmosphere, thermodynamic energy convergence is also important, especially during the winter, In most places, precipitation is largely balanced by thermodynamic energy divergence. Anomalously high surface temperatures appear to be mainly related to decreased surface evaporation. Anomalously high (low) precipitation variations may also be related to anomalously high thermodynamic energy divergence (convergence). Unfortunately, residual terms, which are slightly noticeable for the GCIP climatological balances, are especially noticeable for the anomalous atmospheric balances. C1 NATL CTR ENVIRONM PREDICT,CLIMATE PREDICT CTR,WASHINGTON,DC. RP Roads, J (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,DIV CLIMATE RES,LA JOLLA,CA 92093, USA. NR 38 TC 13 Z9 13 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 1 PY 1997 VL 54 IS 13 BP 1776 EP 1794 DI 10.1175/1520-0469(1997)054<1776:GSGEB>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH843 UT WOS:A1997XH84300007 ER PT J AU Argento, C Jagota, A Carter, WC AF Argento, C Jagota, A Carter, WC TI Surface formulation for molecular interactions of macroscopic bodies SO JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS LA English DT Article DE adhesion and adhesives; contact mechanics; granular material; numerical algorithms ID FRACTURE; CONTACT; FORCES AB The determination of forces resulting from molecular interactions between macroscopic bodies is important for the analysis of a variety of processes such as sintering, adhesion, and fracture. Body forces resulting from these interactions are usually concentrated near the surfaces of the bodies and are responsible for phenomena such as surface tension and surface energy. In the formulation presented here, the volume integrated intermolecular force between bodies is partitioned to obtain a distribution of effective surface tractions. This new surface formulation eliminates the geometrical restrictions associated with the commonly used Derjaguin approximation. The influence of each body on the surface of any other body is represented by a new quantity: the inter-surface stress tensor. Additional forces resulting from interactions within the body, the surface tension, have been considered for liquid-like materials. These self interactions are modeled by the classical Young-Laplace equation relating the effective traction on a surface to the energy of the surface and its curvature. The surface formulation offers considerable reduction in computational complexity compared to a formulation. based on body forces. The efficacy of the technique is demonstrated using several examples. (C) 1997 Elsevier Science Ltd. C1 INDIAN INST TECHNOL,DEPT APPL MECH,DELHI 110016,INDIA. NIST,DIV CERAM,GAITHERSBURG,MD 20899. RP Argento, C (reprint author), DUPONT CO INC,CENT RES & DEV,WILMINGTON,DE 19880, USA. RI Carter, W/K-2406-2012 NR 31 TC 52 Z9 53 U1 2 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-5096 J9 J MECH PHYS SOLIDS JI J. Mech. Phys. Solids PD JUL PY 1997 VL 45 IS 7 BP 1161 EP 1183 DI 10.1016/S0022-5096(96)00121-4 PG 23 WC Materials Science, Multidisciplinary; Mechanics; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA XG420 UT WOS:A1997XG42000006 ER PT J AU Hill, RJ Frehlich, RG AF Hill, RJ Frehlich, RG TI Probability distribution of irradiance for the onset of strong scintillation SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID I-K DISTRIBUTION; INNER-SCALE; ATMOSPHERIC-TURBULENCE; OPTICAL-SCINTILLATION; NUMERICAL-SIMULATION; DENSITY FUNCTION; SURFACE-LAYER; PROPAGATION; SPECTRUM; SCATTERING AB We calculated the probability distribution function (PDF) from simulations for an initially spherical wave propagated through homogeneous atmospheric turbulence. The onset of strong scintillation was calculated. By onset of strong scintillation, we mean conditions of weak scintillation changing to the condition of strong focusing. In addition, one case in the saturation regime was calculated. The simulations' PDF's are compared with several heuristic models of the PDF and are seen to progress from close to log normal for the cases of weakest scintillation to close to the log normally modulated exponential PDF (LNME PDF) for the cases of strong scintillation. The simulations' PDF's are not in agreement with the K PDF for any of the calculated eases. The best agreement was obtained in comparison with Beckmann's PDF [P. Beckmann, Probability in Communication Engineering (Harcourt, Brace, & World, 1967)]. Beckmann's PDF varies from being the log-normal PDF for weak scintillation to being the LNME PDF for strong scintillation and progresses further to the theoretically expected exponential PDF in the limit of saturated scintillation. We recommend that simulation be used to predict the irradiance PDF for plane and diverged waves in homogeneous turbulence in preference to using heuristic models. More complicated propagation cases remain in the domain of heuristic argumentation. (C) 1997 Optical Society of America. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. RP Hill, RJ (reprint author), NOAA,ENVIRONM RES LAB,ENVIRONM TECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 37 TC 71 Z9 79 U1 0 U2 11 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD JUL PY 1997 VL 14 IS 7 BP 1530 EP 1540 DI 10.1364/JOSAA.14.001530 PG 11 WC Optics SC Optics GA XG645 UT WOS:A1997XG64500017 ER PT J AU Jablonski, A Powell, CJ AF Jablonski, A Powell, CJ TI Evaluation of correction parameters for elastic-scattering effects in x-ray photoelectron spectroscopy and Auger electron spectroscopy SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID MEAN FREE PATHS; SURFACE-ANALYSIS; ANGULAR-DISTRIBUTIONS; 50-2000-EV RANGE; QUANTIFICATION; BACKSCATTERING; SOLIDS; XPS AB We describe a relatively simple, reliable, and fast approach for quantitative surface analyses by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) that significantly improves the accuracy of analyses of polycrystalline solids, The common formalism of XPS and AES is based on the assumption, now known to be incorrect, that elastic-electron-scattering effects are negligible. These effects can be taken into account by the use of correction parameters (two for XPS and one for AES) in a modified formalism. These correction parameters can be conveniently expressed in terms of the ratio zeta of the transport mean free path to the inelastic mean free path for a particular material and electron energy, and we give an improved procedure for determining this ratio for elemental solids and compounds at electron energies ranging from 50 to 2000 eV. We test the utility and validity of the derived correction parameters for XPS based on comparisons with parameter values and photoelectron intensities derived from Monte Carlo simulations for some 400 photoelectron lines in 27 elements excited by ME and Al characteristic x rays. It is pointed out that the systematic errors associated with the neglect of elastic-electron scattering in XPS depend on the instrumental configuration, and range from -20% to 30% for two WS configurations investigated here. With the use of the modified XPS formalism and the two correction parameters, these errors were reduced to between -3% and 2% for most of the photoelectron lines, although with a few lines the errors were as large as -10%. Good performance of the modified formalism for AES has been reported previously. We describe and discuss the application of this approach for surface analyses of multi-component solids. The improved procedure for calculating the ratio zeta can also be used for estimation of the mean escape depth of photoelectrons and Auger electrons. (C) 1997 American Vacuum Society. C1 NIST,SURFACE & MICROANAL SCI DIV,GAITHERSBURG,MD 20899. RP Jablonski, A (reprint author), POLISH ACAD SCI,INST PHYS CHEM,KASPRZAKA 44-52,PL-01224 WARSAW,POLAND. NR 28 TC 33 Z9 33 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1997 VL 15 IS 4 BP 2095 EP 2106 DI 10.1116/1.580615 PG 12 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XL335 UT WOS:A1997XL33500043 ER PT J AU Materer, N Goodman, RS Leone, SR AF Materer, N Goodman, RS Leone, SR TI Laser single-photon ionization mass spectrometry measurements of SiCl and SiCl2 during thermal etching of Si(100) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID DOPED POLYCRYSTALLINE SILICON; CHLORINE-CONTAINING PLASMAS; DESORPTION-KINETICS; MOLECULAR CHLORINE; RATE CONSTANTS; SPECTROSCOPY; ADSORPTION; SI(111)7X7; GENERATION; RADIATION AB Pulsed laser single-photon ionization time-of-flight mass spectrometry is used to investigate the etch products resulting from thermal etching of Si(100) with molecular chlorine over a temperature range of 1023-1373 K and a pressure range of 10(-5)-10(-4) Pa. In this regime, two thermal etch products, SiCl2 and SiCl, are directly observed by ionization without fragmentation using 118 nm light. Over this temperature and pressure range, the desorption fluxes of SiCl2 and SiCl are proportional to the dosing chlorine pressure. A phenomenological activation energy of 0.36+/-0.03 eV is observed for the SiCl desorption flux from an Arrhenius plot. The SiCl2 product flux exhibits a complex temperature dependence, first. increasing and then decreasing, and thus this rate is controlled by at least two pathways. One pathway in the lower temperature regime may be a direct desorption channel. The other process at higher temperatures may be a competing reaction that limits the precursor species, most likely SiCl, for the formation of SiCl2 on the surface. The ability to detect the radical species without mass spectral cracking provides the potential to unravel such complex pathways. (C) 1997 American Vacuum Society. C1 NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NR 40 TC 16 Z9 16 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1997 VL 15 IS 4 BP 2134 EP 2142 DI 10.1116/1.580619 PG 9 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XL335 UT WOS:A1997XL33500047 ER PT J AU Jousten, K Filippelli, AR Tilford, CR Redgrave, FJ AF Jousten, K Filippelli, AR Tilford, CR Redgrave, FJ TI Comparison of the standards for high and ultrahigh vacuum at three national standards laboratories SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID CALIBRATION; GAUGES AB A preliminary phase of an international comparison of standards for high and ultrahigh vacuum was carried out by the National Institute of Standards and Technology (NIST), the National Physical Laboratory-Teddington (NPL-UK), and the Physikalisch-Technische Bundesanstalt (PTB). A spinning rotor gauge (SRG), a Bayard-Alpert gauge (BAG) and an extractor gauge (EXG) were chosen as transfer standards. The comparison was carried out in a star-like pattern with PTB as pilot laboratory. The argon pressures generated by the standards at 9 x 10(-4) Pa were compared by measuring the accommodation coefficient of the SRG, the pressures from 3 x 10(-7) Pa to 9 x 10(-4) Pa by measuring the sensitivity of the two ionization gauges. The accommodation coefficients determined at NIST and PTB indicate a difference between the pressures generated by the NIST and PTB standards of (P-NIST-P-PTB)/(PTB)=(0.09 +/- 0.11)% (standard or one-sigma uncertainty). For the pressures between 3 x 10(-7) Pa and 9 x 10(-4) Pa the results obtained at NIST and PTB had a mean difference of [(P-NIST-P-PTB)/P-PTB]=(0.24+/-0.12)%, With a maximum difference of (1.2+/-0.6) at the lowest pressure. The NIST-PTB differences are all within the combined uncertainties of the two standards. Large transfer standard instabilities and inconsistent results in a first NPL-PTB comparison prompted a repeat set of measurements. An average of the two sets of SRG measurements indicates a significant difference between NPL and PTB standards of (P-NPL-P-PTB)/P-PTB = (1.31 +/- 0.14)%. The two sets of ionization gauge measurements effectively repeated, but the results for the individual gauges are inconsistent. The EXG results indicate no significant pressure dependence in the difference between the standards for pressures below 9 x 10(-4) Pa. The BAG results indicate a significant increase in the difference between the standards as the pressure is reduced, with (P-NPL-P-PTB)/P-PTB becoming as large as 5% or 6% at the lower pressures. Several potential problems with the BAG operation were identified, which might indicate that more confidence should be placed in the EXG results. However, there is no reliable evidence that the BAG comparison results were actually affected, and the results for each gauge are so internally consistent that neither can be rejected. Further work should be directed towards resolving this discrepancy. (C) 1997 American Vacuum Society. C1 PHYS TECH BUNDESANSTALT,D-10587 BERLIN,GERMANY. NIST,GAITHERSBURG,MD 20899. NATL PHYS LAB,TEDDINGTON TW11 0LW,MIDDX,ENGLAND. NR 19 TC 13 Z9 13 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1997 VL 15 IS 4 BP 2395 EP 2406 DI 10.1116/1.580754 PG 12 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XL335 UT WOS:A1997XL33500087 ER PT J AU Goodman, RS Materer, N Leone, SR AF Goodman, RS Materer, N Leone, SR TI Ar, N-2 and Cl-2 electron cyclotron resonance plasmas measured by time-of-flight analysis: Neutral kinetic energies and source gas cracking SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID CROSS-SECTION MEASUREMENTS; IMPACT-IONIZATION; ION-TRANSPORT; CHLORINE; TEMPERATURES; ATOMS; FLUORESCENCE; DISCHARGES; REACTORS; DENSITY AB Neutral mean kinetic energies, ion intensities, and neutral source gas cracking from Ar, N-2, and Cl-2 electron cyclotron resonance (ECR) plasmas, are measured by modulated beam time-of-flight (TOF) analysis. The TOF distributions are characterized by a two component form consisting of an effusive Maxwell-Boltzmann distribution and a fast Gaussian component, that accounts for nonthermal species produced in the source. The mean kinetic energies of neutral species are found to range between 0.04 and 0.45 eV, depending on species and plasma conditions. Mean kinetic energies increase at a nearly constant rate, with decreasing pressure from 8.0 x 10(-2) to 2.5 x 10(-2) Pa with constant applied microwave power. At pressures below 2.5 X 10(-2) Pa, the neutral mean kinetic energies sharply increase. This sharp increase in neutral mean kinetic energy is attributed to an abrupt increase in the ion flux out of the source. The increase in kinetic energy can be separated into two contributions, (i) thermal at higher pressures and (ii) nonthermal at lower pressures. This effect is much stronger for atomic neutrals than for molecular neutrals, where internal degrees of freedom can accept energy in momentum transfer collisions. Cracking of N-2 and Cl-2 is also examined as a function of source pressure at constant microwave power. The N:N-2 flux ratio from the ECR source varies between 0.2 and 1.4. The Cl:Cl-2 flux ratio varies from 10 to 16, indicating a very high degree of dissociation in the plasma. Both flux ratios decrease with increasing source pressure. The total flux of Cl increases with increasing source pressure over the entire range, while the N atom flux peaks at similar to 1.3 X 10(-2) Pa and decreases on either side of this pressure. (C) 1997 American Vacuum Society. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Goodman, RS (reprint author), UNIV COLORADO,JILA,NATL INST STAND & TECHNOL,BOULDER,CO 80309, USA. NR 38 TC 7 Z9 7 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1997 VL 15 IS 4 BP 971 EP 982 DI 10.1116/1.589517 PG 12 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA XT088 UT WOS:A1997XT08800036 ER PT J AU Simiu, E Stathopoulos, T AF Simiu, E Stathopoulos, T TI Codification of wind loads on buildings using bluff body aerodynamics and climatological data bases SO JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS LA English DT Article; Proceedings Paper CT 3rd Colloquium on Bluff Body Aerodynamics and Applications CY JUL 28-AUG 01, 1996 CL VIRGINIA POLYTECH INST & STATE UNIV, BLACKSBURG, VIRGINIA SP Natl Sci Fdn, Amer Soc Civil Engineers, Aerosp Div, Amer Assoc Wind Engn HO VIRGINIA POLYTECH INST & STATE UNIV AB Current data storage and computational capabilities allow the development of a new generation of standards whose provisions on wind loads can be structured as knowledge-based systems drawing the requisite information from large data bases. We show several examples demonstrating that such provisions could be significantly more realistic and risk-consistent than their conventional counterparts, which are of necessity based on reductive formulas, tables and plots. We point out the necessary interaction between development of knowledge-based standard provisions and the acquisition of aerodynamics and wind climatology data. Finally, we suggest that in addition to serving structural designers' needs, knowledge-based standard provisions could serve the insurance industry as certified hazard assessment tools that would be more realistic and dependable than similar tools developed without the benefit of careful public scrutiny and broad professional consensus. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Concordia Univ, Fac Engn & Comp Sci, Montreal, PQ H3G 1M8, Canada. RP Simiu, E (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 15 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6105 J9 J WIND ENG IND AEROD JI J. Wind Eng. Ind. Aerodyn. PD JUL-OCT PY 1997 VL 71 BP 497 EP 506 PG 10 WC Engineering, Civil; Mechanics SC Engineering; Mechanics GA YU923 UT WOS:000071770200043 ER PT J AU Antonelis, GA Sinclair, EH Ream, RR Robson, BW AF Antonelis, GA Sinclair, EH Ream, RR Robson, BW TI Inter-island variation in the diet of female northern fur seals (Callorhinus ursinus) in the Bering sea SO JOURNAL OF ZOOLOGY LA English DT Article ID ZALOPHUS-CALIFORNIANUS; PREY; FISH; WEIGHT; LIONS; FECES; FOOD AB The diet of adult female northern fur seals (Callorhinus ursinus) is examined through the analysis of faecal material collected during the summer breeding season at three breeding locations in the Bering Sea: St. Paul Island (1988, 1990) and St. George Island (1988, 1990) of the Pribilof Islands Group (USA), and Medny Island (1990) of the Commander Islands Group (Russia). Prey consumption varies annually and accordingly with the physical and biological environment surrounding each island. Juvenile walleye pollock (Theragra chalcogramma) is the most common prey of northern fur seals from St. Paul Island; the island is surrounded by a broad neritic environment with widely separated frontal zones and is the greatest distance from the continental shelf-edge. Gonatid squid (Gonatopsis borealis/Berryteuthis magister and Gonatus madokai/Gonatus middendorffi) were the most common prey of northern fur seals from Medny Island; the island is surrounded by a compressed neritic environment and is adjacent to the continental shelf-edge and the oceanic marine environment. A combination of walleye pollock and gonatid squid is consumed by northern fur seals from St. George Island; the island has a surrounding oceanographic environment intermediate between the other two islands. Variability in predation on walleye pollock is consistent with fishery information concerning the relative abundance and availability of walleye pollock around St. George and St. Paul Islands. The abundance and availability of these prey resources during the summer breeding season are key factors which influence the health and growth of the northern fur seal populations in the Bering Sea. C1 NOAA, NATL MARINE FISHERIES SERV, ALASKA FISHERIES SCI CTR, NATL MARINE MAMMAL LAB, SEATTLE, WA 98115 USA. NR 61 TC 47 Z9 48 U1 2 U2 7 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0952-8369 EI 1469-7998 J9 J ZOOL JI J. Zool. PD JUL PY 1997 VL 242 BP 435 EP 451 PN 3 PG 17 WC Zoology SC Zoology GA XM704 UT WOS:A1997XM70400003 ER PT J AU Tester, PA Steidinger, KA AF Tester, PA Steidinger, KA TI Gymnodinium breve red tide blooms: Initiation, transport, and consequences of surface circulation SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID FLORIDA CONTINENTAL-SHELF; GULF-OF-MEXICO; LOOP CURRENT; STREAM; WATERS; INTRUSION; SATELLITE; NORTH AB From its source waters in the Gulf of Mexico the led tide dinoflagellate, Gymnodinium breve is moved throughout its oceanic range by major currents and eddy systems. The continental shelf off the west coast of Florida experiences frequent G. breve blooms (in 21 of the last 22 years) where the spatially explicit phases of G. breve blooms are closely coupled to physical processes. Bloom initiation occurs offshore and in association with shoreward movements of the Loop Current or spinoff eddies. A midshelf front maintained by seasonal wind reversals along the Florida west coast may serve as a growth and accumulation region for G. breve blooms and contribute to the reinoculation of nearshore waters. Local eddy circulation in the northeastern Gulf of Mexico and in the Dry Tortugas affects the retention and coastal distribution of blooms while the Florida Current and Gulf Stream transport cells out of the Gulf of Mexico and into the U.S. South Atlantic Eight. The causes of bloom dissipation are not well known but mixing or disruption of the water mass supporting G. bp-eve cells, especially in combination with declining water temperatures, are important factors. C1 FLORIDA DEPT ENVIRONM PROTECT, FLORIDA MARINE RES INST, ST PETERSBURG, FL 33712 USA. RP Tester, PA (reprint author), NOAA, NATL MARINE FISHERIES SERV, SE FISHERIES CTR, BEAUFORT LAB, BEAUFORT, NC 28516 USA. NR 66 TC 189 Z9 194 U1 3 U2 24 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0024-3590 EI 1939-5590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD JUL PY 1997 VL 42 IS 5 BP 1039 EP 1051 PN 2 PG 13 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA YK663 UT WOS:A1997YK66300004 ER PT J AU Turner, JT Tester, PA AF Turner, JT Tester, PA TI Toxic marine phytoplankton, zooplankton grazers, and pelagic food webs SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Review ID DINOFLAGELLATE ALEXANDRIUM-EXCAVATUM; DIATOM NITZSCHIA-PUNGENS; DOMOIC ACID PRODUCTION; RED-TIDE FLAGELLATE; PHAEOCYSTIS-POUCHETII; FISH KILLS; GONYAULAX-TAMARENSIS; CALANUS-PACIFICUS; NARRAGANSETT-BAY; RHODE-ISLAND AB Interactions between toxic phytoplankton and their zooplankton grazers are complex. Some zooplankters ingest some toxic phytoplankters with no apparent harm, whereas others are deleteriously affected. Phycotoxins vary in their modes of action, levels of toxicity and solubility, and affect grazers in different ways. Beyond effects on direct grazers, toxins may accumulate in and be transferred through marine food webs, affecting consumers at higher trophic levels, including fish, seabirds, and marine mammals. Grazers of toxic phytoplankton include protists as well as metazoans, and the impact of zooplankton grazing on development or termination of toxic blooms is poorly understood. In most interactions of toxic phytoplankters with grazers and other marine food-web components, outcomes are situation-specific, and extrapolation of results from one set of circumstances' to another may be inappropriate. C1 NOAA, NATL MARINE FISHERIES SERV, SE FISHERIES CTR, BEAUFORT LAB, BEAUFORT, NC 28516 USA. RP Turner, JT (reprint author), SE MASSACHUSETTS UNIV, DEPT BIOL, N DARTMOUTH, MA 02747 USA. NR 152 TC 273 Z9 286 U1 7 U2 55 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0024-3590 EI 1939-5590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD JUL PY 1997 VL 42 IS 5 BP 1203 EP 1214 PN 2 PG 12 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA YK663 UT WOS:A1997YK66300016 ER PT J AU Millie, DF Schofield, OM Kirkpatrick, GJ Johnsen, G Tester, PA Vinyard, BT AF Millie, DF Schofield, OM Kirkpatrick, GJ Johnsen, G Tester, PA Vinyard, BT TI Detection of harmful algal blooms using photopigments and absorption signatures: A case study of the Florida red tide dinoflagellate, Gymnodinium breve SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID PROROCENTRUM-MINIMUM; HETEROCAPSA-PYGMAEA; QUANTUM YIELD; PHYTOPLANKTON ABSORPTION; PHOTOSYNTHETIC PIGMENTS; MARINE-PHYTOPLANKTON; CARBON FIXATION; WEST FLORIDA; SPECTRA; VARIABILITY AB The utility of photopigments and absorption signatures to detect and enumerate the red tide dinoflagellate, Gymnodinium breve, was evaluated in laboratory cultures and in natural assemblages. The carotenoid, gyroxanthin-diester, was an adequate biomarker for G. breve biomass; water-column concentrations corresponded with cell standing crops and chlorophyll a concentrations during bloom events in Sarasota Bay, Florida. Unlike other carotenoids, the relative abundance of gyroxanthin-diester did not change throughout a range of physiological states in culture and the gyroxanthin-diester: chlorophyll a ratio exhibited little variability in a natural assemblage during bloom senescence. Stepwise discriminant analysis indicated that wavelengths indicative of in vivo absorption by accessory chlorophylls and carotenoids could correctly discern spectra of the fucoxanthin-containing G, breve from spectra of peridinin-containing dinoflagellates, a diatom, a haptophyte, and a prasinophyte. With the use of a similarity algorithm, the increasing contribution of G. breve was discerned in absorption spectra (and corresponding fourth-derivative plots) for hypothetical mixed assemblages. However, the absorption properties of chlorophyll c-containing algae vary little among taxa and it is difficult to discern the contribution of accessory chlorophylls and carotenoids caused by cell packaging. Therefore, the use of absorption spectra alone may not identify the contribution of a chlorophyll c-containing taxon to the composite spectrum of a mixed assemblage. This difficulty in distinguishing among spectra can be minimized by using the similarity algorithm in conjunction with fourth-derivative analysis. C1 MOTE MARINE LAB,SARASOTA,FL 34236. RUTGERS STATE UNIV,INST MARINE & COASTAL SCI,NEW BRUNSWICK,NJ 08903. UNIV TRONDHEIM MUSEUM,TRONDHEIM BIOL STN,N-7018 TRONDHEIM,NORWAY. NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES CTR,BEAUFORT LAB,BEAUFORT,NC 28516. OLD DOMINION UNIV,DEPT OCEANOG,NORFOLK,VA 23508. RP Millie, DF (reprint author), USDA ARS,SO REG RES CTR,POB 19687,NEW ORLEANS,LA 70179, USA. RI Johnsen, Geir/A-1689-2009 NR 69 TC 143 Z9 162 U1 1 U2 18 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD JUL PY 1997 VL 42 IS 5 BP 1240 EP 1251 PN 2 PG 12 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA YK663 UT WOS:A1997YK66300019 ER PT J AU Sunda, WG AF Sunda, WG TI Control of dissolved iron concentrations in the world ocean: A comment SO MARINE CHEMISTRY LA English DT Editorial Material ID CENTRAL NORTH PACIFIC; PHYTOPLANKTON; VERTEX; CARBON; GROWTH RP Sunda, WG (reprint author), NOAA,NATL MARINE FISHERIES SERV,BEAUFORD LAB,101 PIVERS ISL RD,BEAUFORT,NC 28516, USA. NR 17 TC 54 Z9 54 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-4203 J9 MAR CHEM JI Mar. Chem. PD JUL PY 1997 VL 57 IS 3-4 BP 169 EP 172 DI 10.1016/S0304-4203(97)00045-5 PG 4 WC Chemistry, Multidisciplinary; Oceanography SC Chemistry; Oceanography GA XT791 UT WOS:A1997XT79100003 ER PT J AU Clapham, PJ Leatherwood, S Szczepaniak, I Brownell, RL AF Clapham, PJ Leatherwood, S Szczepaniak, I Brownell, RL TI Catches of humpback and other whales from shore stations at Moss Landing and Trinidad, California, 1919-1926 SO MARINE MAMMAL SCIENCE LA English DT Article DE humpback whale; fin whale; sei whale; North Pacific; whaling; population structure; prey; reproduction; abundance ID MEGAPTERA-NOVAEANGLIAE; BALAENOPTERA-PHYSALUS; AMMODYTES-AMERICANUS; BALEEN WHALES; SOUTHERN GULF; MAINE; BEHAVIOR; POPULATION; MIGRATION; ABUNDANCE AB Logbook data from California shore whaling stations at Moss Landing (1919-1922 and 1924) and Trinidad (1920 and 1922-1926) are analyzed. The logs for the two stations record the caking of 2,111 whales, including 1,871 humpbacks, 177 fin whales, 26 sei whales, 3 blue whales, 12 sperm whales, 7 gray whales, 1 sight whale, 1 Baird's beaked whale, and 13 whales of unspecified type (probably humpbacks). Most whales were taken from spring to autumn, but catches were made in all months of some years. The sex ratios of humpback, fin, and sei whales (the three species with sufficient sample sizes to test) did not differ from parity. Primary prey, determined from stomach contents, included sardines and euphausiids for both humpback and fin whales, and ''plankton'' (probably euphausiids) for sei whales. The prevalence of pregnancy was 0.46 among mature female humpbacks and 0.43 among mature female fin whales, although these values are reported with caution. Information on length distribution for all species is summarized. Analysis of the catch data for this and other areas supports the current view that humpback whales along the west coast of the continental United States comprise a single feeding stock and also suggests that the present population is well below pre-exploitation levels. C1 NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,LA JOLLA,CA 92038. OCEAN PK CONSERVAT FDN,ABERDEEN,HONG KONG. CALIF ACAD SCI,DEPT ORNITHOL,SAN FRANCISCO,CA 94118. CALIF ACAD SCI,DEPT MAMMAL,SAN FRANCISCO,CA 94118. NR 63 TC 28 Z9 30 U1 3 U2 14 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1997 VL 13 IS 3 BP 368 EP 394 DI 10.1111/j.1748-7692.1997.tb00646.x PG 27 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA XG057 UT WOS:A1997XG05700002 ER PT J AU Vidal, O Barlow, J Hurtado, LA Torre, J Cendon, P Ojeda, Z AF Vidal, O Barlow, J Hurtado, LA Torre, J Cendon, P Ojeda, Z TI Distribution and abundance of the Amazon river dolphin (Inia geoffrensis) and the tucuxi (Sotalia fluviatilis) in the Upper Amazon river SO MARINE MAMMAL SCIENCE LA English DT Article DE Amazon dolphins; survey techniques; distribution; abundance; Inia; Sotalia; bufeo colorado; tucuxi; boto; bufeo negro ID SHIP SURVEYS; CALIFORNIA AB A boat survey was conducted from 5 to 26 June 1993 to estimate the abundance of the Amazon river dolphin (Inia geoffrensis) and the tucuxi (Solatia fluviatilis) along ca. 120 km of the Amazon River bordering Colombia, Peru, and Brazil. Two survey methods were used: line transects during 5 d and strip transects during 15 d. The line transects were used to estimate the abundance of both species in the main channels of the Amazon at distances greater than 200 m from river banks and islands, and strip transects were used to estimate abundance in the remainder of the habitat. A total of 29 sightings was obtained using line transects, including 8 of Inia, 15 of Solatia, and 6 with both species present. The total number of sightings made while using strip transects was 143, including 78 of Inia, 51 of Solatia, and 14 with both species present. The distributions of sightings with respect to distance from the nearest bank were not significantly different between the two species. Based on the results from the two methods, we estimate that there are 346 (CV = 0.12) Inia and 409 (CV = 0.13) Solatia in the study area. Overall, the mean group size for Inia was 2.9 individuals and for Solatia was 3.9 individuals. Inia density (dolphin/km(2)) was highest in tributaries (4.8), followed by areas around islands (2.7) and along main banks (2.0); while Solatia density was highest in lakes (8.6), followed by areas along main banks (2.8) and around islands (2.0). These are among the highest densities measured to date for any cetacean. C1 ITESM,DEPT CIENCIAS MARINAS,GUAYMAS 85400,SONORA,MEXICO. ITESM,CECARENA,GUAYMAS 85400,SONORA,MEXICO. NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,LA JOLLA,CA 92038. RI Hurtado, Luis/B-5953-2008 OI Hurtado, Luis/0000-0002-9773-4996 NR 29 TC 34 Z9 37 U1 1 U2 24 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1997 VL 13 IS 3 BP 427 EP 445 DI 10.1111/j.1748-7692.1997.tb00650.x PG 19 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA XG057 UT WOS:A1997XG05700006 ER PT J AU Fiscus, CH AF Fiscus, CH TI Cephalopod beaks in a Cuvier's beaked whale (Ziphius cavirostris) from Amchitka Island, Alaska SO MARINE MAMMAL SCIENCE LA English DT Article C1 NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,NATL MARINE MAMMAL LAB,SEATTLE,WA 98115. NR 25 TC 8 Z9 9 U1 1 U2 2 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1997 VL 13 IS 3 BP 481 EP 486 DI 10.1111/j.1748-7692.1997.tb00655.x PG 6 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA XG057 UT WOS:A1997XG05700011 ER PT J AU Henshaw, MD LeDuc, RG Chivers, SJ Dizon, AE AF Henshaw, MD LeDuc, RG Chivers, SJ Dizon, AE TI Identifying beaked whales (family Ziphiidae) using mtDNA sequences SO MARINE MAMMAL SCIENCE LA English DT Article ID FIN WHALE; DNA; PHYSALUS RP Henshaw, MD (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,POB 271,LA JOLLA,CA 92038, USA. NR 24 TC 13 Z9 17 U1 0 U2 2 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1997 VL 13 IS 3 BP 487 EP 495 DI 10.1111/j.1748-7692.1997.tb00656.x PG 9 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA XG057 UT WOS:A1997XG05700012 ER PT J AU Naidu, AS Blanchard, A Kelley, JJ Goering, JJ Hameedi, MJ Baskaran, M AF Naidu, AS Blanchard, A Kelley, JJ Goering, JJ Hameedi, MJ Baskaran, M TI Heavy metals in Chukchi Sea sediments as compared to selected circum-arctic shelves SO MARINE POLLUTION BULLETIN LA English DT Article ID TRACE-METALS; KARA SEA; CONTAMINANTS; ESTUARINE; YENISEY; BLUBBER; RUSSIA; MARINE; OB AB Surficial sediments from 31 stations on the northeastern Chukchi Sea, Alaskan Arctic were analysed by AAS and ICP-AES for Si, Al, Fe, Mn, Cu, Cr, Co, Zn, Ni and V, The metal concentrations are related to the sediment granulometry and show no correlations with organic carbon. Presumably all the heavy metals, except Cr and Co, are either adsorbed on clays and/or coprecipitated with ferrimanganic hydroxide. Cobalt is partitioned in an unknown mineral phase within the sand fraction. Comparison of the heavy metal concentrations in muds of the Chukchi Sea with those of the high arctic shelves of Russia, East Greenland and the Beaufort Sea shows relatively lower levels of most metals in the Chukchi, Presumably these disparities are related to regional differences in sediment chemistries inherited from natural terrigenous sources rather than to any enhanced pollution in the non-Chukchi areas. It is suggested that the concentrations and accumulation rates of the heavy metals reported here can serve as reliable baselines to monitor metal pollution in the Chukchi Sea. (C) 1997 Elsevier Science Ltd. All rights reserved. C1 Univ Alaska, Inst Marine Sci, Fairbanks, AK 99775 USA. NOAA, ORCA2, Silver Spring, MD 20910 USA. Texas A&M Univ, Dept Oceanog, Galveston, TX 77551 USA. RP Univ Alaska, Inst Marine Sci, Fairbanks, AK 99775 USA. RI Blanchard, Arny/C-2429-2008; OI Baskaran, Mark/0000-0002-2218-4328 NR 48 TC 22 Z9 27 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD JUL-DEC PY 1997 VL 35 IS 7-12 BP 260 EP 269 DI 10.1016/S0025-326X(96)00154-3 PG 10 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 101PK UT WOS:000074877200008 ER PT J AU Cantillo, AY Lauenstein, GG OConnor, TP AF Cantillo, AY Lauenstein, GG OConnor, TP TI Mollusc and sediment contaminant levels and trends in south Florida coastal waters SO MARINE POLLUTION BULLETIN LA English DT Article ID BUTYLTINS; MEXICO; GULF AB During the past 50 years, the south Florida ecosystem has been subject to an increase in human population and anthropogenic activity. Concentrations of organic and inorganic contaminants in sediments and molluscs collected in south Florida from 1986 to 1994 show temporal and spatial trends that reflect anthropogenic influence in areas removed from large population centers. Generally, contaminant levels found in south Florida sites are low compared with those found nationwide and as low as any found in uncontaminted sites in Central and South America for which bivalves were collected as part of the International Mussel Watch Program. RP NOAA, NATL OCEAN SERV, OFF OCEAN RESOURCES CONSERVAT & ASSESSMENT, 1305 EAST WEST HWY, SILVER SPRING, MD 20910 USA. NR 16 TC 23 Z9 24 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD JUL PY 1997 VL 34 IS 7 BP 511 EP 521 DI 10.1016/S0025-326X(96)00152-X PG 11 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA XW552 UT WOS:A1997XW55200013 ER PT J AU Schneider, MC Gu, JP Beckermann, C Boettinger, WJ Kattner, UR AF Schneider, MC Gu, JP Beckermann, C Boettinger, WJ Kattner, UR TI Modeling of micro- and macrosegregation and freckle formation in single-crystal nickel-base superalloy directional solidification SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID PHASE-DIAGRAM APPROACH; THERMOSOLUTAL CONVECTION; ALLOY SOLIDIFICATION; LIQUATION CRACKING; BINARY-ALLOYS; LIQUID AB The formation of macrosegregation and freckles by multicomponent thermosolutal convection during the directional solidification of single-crystal Ni-base superalloys is numerically simulated. The model links a previously developed thermodynamic phase equilibrium subroutine with an existing code for simultaneously solving the macroscopic mass, momentum, energy, and species conservation equations for solidification of a multicomponent alloy. Simulation results are presented for a variety of casting speeds and imposed thermal gradients and for two alloy compositions. It is found that for a given alloy composition, the onset of convection and freckle formation occurs at a critical primary dendrite arm spacing, which agrees well with previous experimental findings. The predicted number and shape of the freckle chains in the unstable cases also agree qualitatively with experimental observations. Finally, it is demonstrated how the onset and nature of convection and macrosegregation vary with alloy composition. It is concluded that the present model can provide a valuable tool in predicting freckle defects in directional solidification of Ni-base superalloys. C1 UNIV IOWA,DEPT MECH ENGN,IOWA CITY,IA 52242. NIST,DIV MET,GAITHERSBURG,MD 20899. RP Schneider, MC (reprint author), MAGMA GMBH,SOFTWARE DEV,D-52072 AACHEN,GERMANY. RI Beckermann, Christoph/F-7158-2010 OI Beckermann, Christoph/0000-0002-9976-0995 NR 43 TC 135 Z9 139 U1 11 U2 62 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD JUL PY 1997 VL 28 IS 7 BP 1517 EP 1531 DI 10.1007/s11661-997-0214-3 PG 15 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA XL481 UT WOS:A1997XL48100012 ER PT J AU Braun, RJ Murray, BT Soto, J AF Braun, RJ Murray, BT Soto, J TI Adaptive finite-difference computations of dendritic growth using a phase-field model SO MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING LA English DT Article ID LARGE SUPERCOOLINGS; OPERATING STATE; SOLIDIFICATION; ALLOY; SIMULATIONS AB A phase-field model in two dimensions with surface energy anisotropy is used to simulate dendritic solidification of a pure material from its undercooled melt. The computations are performed using a general purpose adaptive mesh finite-difference algorithm, which was designed to solve coupled sets of nonlinear parabolic partial differential equations. The adaptive computations are compared with a fixed-grid calculation at a dimensionless undercooling of 0.8 using finite-difference schemes developed specifically to solve the phase-field equations. Both algorithms were optimized for vector processors. The comparison is used to discuss the advantages and disadvantages of each approach when used to solve the phase-field equations for the complicated interfacial shapes associated with dendritic solidification. Additionally, the adaptive algorithm is used to simulate dendritic growth for undercoolings as small as 0.1, and results are presented for different values of interface thickness. The results show that a better treatment of the outer boundaries is necessary in order to accurately represent the extent of the thermal field at small undercoolings. C1 NIST,GAITHERSBURG,MD 20899. RP Braun, RJ (reprint author), UNIV DELAWARE,NEWARK,DE 19716, USA. NR 32 TC 7 Z9 7 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0965-0393 J9 MODEL SIMUL MATER SC JI Model. Simul. Mater. Sci. Eng. PD JUL PY 1997 VL 5 IS 4 BP 365 EP 380 DI 10.1088/0965-0393/5/4/006 PG 16 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA XW773 UT WOS:A1997XW77300006 ER PT J AU Rosenbaum, HC Egan, MG Clapham, PJ Brownell, RL Desalle, R AF Rosenbaum, HC Egan, MG Clapham, PJ Brownell, RL Desalle, R TI An effective method for isolating DNA from historical specimens of baleen SO MOLECULAR ECOLOGY LA English DT Article DE ancient DNA; Cetacea; control region; Eubalaena glacialis; historical population genetics; mitochondrial DNA; museum specimens ID POLYMERASE CHAIN-REACTION; MITOCHONDRIAL-DNA; ANCIENT DNA; MUSEUM SPECIMENS; WHALES; POPULATIONS; SEQUENCES; WOLF AB DNA was isolated from an early twentieth century museum specimen of northern right whale baleen. A system of stringent controls and a novel set of cetacean specific primers eliminated contamination from external sources and ensured the authenticity of the results. Sequence analysis revealed that there were informative nucleotide positions between the museum specimen and extant members of the population and closely related species. The results indicate that museum specimens of baleen can be used to assess historical genetic population structure of the great whales. C1 YALE UNIV, DEPT BIOL, NEW HAVEN, CT 06510 USA. FORDHAM UNIV, DEPT BIOL SCI, BRONX, NY 10458 USA. NATL MARINE FISHERIES SERV, SW FISHERIES SCI CTR, LA JOLLA, CA 92038 USA. SMITHSONIAN INST, NHB 390, MRC 108, WASHINGTON, DC 20560 USA. RP Rosenbaum, HC (reprint author), AMER MUSEUM NAT HIST, MOL SYSTEMAT LAB, 79TH ST & CPW, NEW YORK, NY 10024 USA. NR 20 TC 34 Z9 36 U1 0 U2 3 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0962-1083 EI 1365-294X J9 MOL ECOL JI Mol. Ecol. PD JUL PY 1997 VL 6 IS 7 BP 677 EP 681 DI 10.1046/j.1365-294X.1997.00230.x PG 5 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA XJ105 UT WOS:A1997XJ10500010 PM 9226948 ER PT J AU Shaw, BL Pielke, RA Ziegler, CL AF Shaw, BL Pielke, RA Ziegler, CL TI A three-dimensional numerical simulation of a great plains dryline SO MONTHLY WEATHER REVIEW LA English DT Article ID PLANETARY BOUNDARY-LAYER; SEVERE-STORM ENVIRONMENT; SOIL-MOISTURE; SURFACE CHARACTERISTICS; MESOSCALE CIRCULATIONS; CONVECTIVE STORM; SQUALL-LINE; MIXED-LAYER; MODEL; SENSITIVITY AB A three-dimensional, nonhydrostatic, nested grid version of the Colorado State University Regional Atmospheric Modeling System (RAMS) was used to perform simulations of an actual dryline that was observed as part of the COPS-91 field experiment on 15 May 1991. A control run designed to reproduce the observed conditions as accurately as possible was generated and verified against standard National Weather Service observations, PAM-II observations, M-CLASS soundings, and vertical cross-sectional analyses obtained from the NOAA P-3 aircraft. A representative heterogeneous soil moisture field for use in the control simulation was generated using an antecedent precipitation index (API). Representative vegetation coverage based on the USGS normalized difference vegetation index (NDVI) dataset was input into the model. An additional simulation using a homogeneous soil moisture field is compared to the control run. Results of study indicate that the use of realistic heterogeneous soil moisture and vegetation may be extremely important for accurate prediction of dryline formation and morphology. The effect of variable soil moisture appears to be first order, with large impacts on the strength of the thermal and moisture gradients along the dryline, as well as its position, structure, and movement. C1 COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. USAF, INST TECHNOL, WRIGHT PATTERSON AFB, OH 45433 USA. NOAA, NATL SEVERE STORMS LAB, NORMAN, OK 73069 USA. RI Pielke, Roger/A-5015-2009 NR 62 TC 48 Z9 49 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 1997 VL 125 IS 7 BP 1489 EP 1506 DI 10.1175/1520-0493(1997)125<1489:ATDNSO>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XJ257 UT WOS:A1997XJ25700007 ER PT J AU Holle, RL Bennett, SP AF Holle, RL Bennett, SP TI Lightning ground flashes associated with summer 1990 flash floods and streamflow in Tucson, Arizona: An exploratory study SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE CONVECTIVE SYSTEM; DIRECTION FINDERS; MEXICAN MONSOON; WEATHER AB Eight flash flood events occurred in the Tucson area of southeastern Arizona during the 1990 summer when a high-resolution lightning detection network was operated in the region. A total of 3479 cloud-to-ground lightning flashes was composited with respect to times and locations of these hash floods. The analysis region was a square of 40 km on a side that nearly coincided with a small hydrologic region that drains runoff from high mountains around Tucson and results in streamflow near and through the city. Most lightning in the 40-km-square area occurred between 10 h before the flood and the reported time of the flood. Flashes were most frequent around 2 h prior to the flood, but advance timing was not consistent. The most important factor in determining whether a flash flood report followed lightning was the number of consecutive 5-min periods with two or more flashes in the 40-km-square area. Intensity of the maximum flash rate was not systematically related to the amount of flooding, except that the 2 days with highest lightning frequencies were associated with the most widespread flood effects of the summer in the Tucson area. No precursor was found in positive flashes. While lightning data identified many of the hash flood events and avoided most false detections, the sample size was very small and there were no other cases for an independent test. Streamflow increased abruptly after the occurrence of lightning for two flood periods on 19-20 July and another flood on 24 July. About 2 h after the maximum flash rate, streamflow gauges at three locations in the hydrologic region measured rapid rises in runoff that were indicative of the arrival of hash floods. Additional studies with flashes from an operational lightning detection network need to take into account additional factors, such as different locations, seasons, storm types, and precipitable water in low to midlevels, in order to more fully explore the possibility of lightning strikes providing useful precursors of flash flood events, particularly in rugged semiarid terrain. C1 NOAA,NATL SEVERE STORMS LAB,PHOENIX,AZ. RP Holle, RL (reprint author), NOAA,NATL SEVERE STORMS LAB,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. NR 31 TC 14 Z9 15 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 1997 VL 125 IS 7 BP 1526 EP 1536 DI 10.1175/1520-0493(1997)125<1526:LGFAWS>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XJ257 UT WOS:A1997XJ25700009 ER PT J AU Wilson, CL Blue, JL Omidvar, OM AF Wilson, CL Blue, JL Omidvar, OM TI Training dynamics and neural network performance SO NEURAL NETWORKS LA English DT Article DE neurodynamics; successive regularization; structural stability; optical character recognition; fingerprints; optimization; Boltzmann pruning; sine activation AB We use an analysis of a simple model of recurrent network dynamics to gain qualitative insights into the training dynamics of feedforward multilayer perceptrons (MLPs) used for classification. These insights suggest changes to the training methods used for MLPs that improve network performance significantly. In previous work, the probabilistic neural network (PNN) was shown to provide better zero-reject error performance on character and fingerprint classification problems than radial basis function and MLP-based neural network methods. We will show that perfor- mance equal to or better than PNN can be achieved with a single three-layer MLP by making fundamental changes in the network optimization strategy. These changes are: 1) use of neuron activation functions, which reduce the probability of singular Jacobians; 2) use of successive successive regularization to constrain the volume of the minimized weight space; 3) use of Boltzmann pruning to constrain the dimension of the weight space; 4) use of Prior class probabilities to normalize all error calculations, so that statistically significant samples of rare but important classes can be included without distorting the error surface. All four of these changes are made in the inner loop of a conjugate gradient optimization iteration and are intended to simplify the training dynamics of the optimization. On handprinted digits and fingerprint classification problems these modifications improve error-reject performance by factors between 2 and 4, and reduce network size by 40-60%. (C) 1997 Elsevier Science Ltd. C1 UNIV DIST COLUMBIA,DEPT COMP SCI,WASHINGTON,DC 20008. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. NR 28 TC 10 Z9 11 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0893-6080 J9 NEURAL NETWORKS JI Neural Netw. PD JUL PY 1997 VL 10 IS 5 BP 907 EP 923 DI 10.1016/S0893-6080(96)00119-0 PG 17 WC Computer Science, Artificial Intelligence SC Computer Science GA XL505 UT WOS:A1997XL50500011 ER PT J AU Venkataraman, R Fleming, RF McGarry, ED AF Venkataraman, R Fleming, RF McGarry, ED TI A measurement-based method to determine the photofission contribution to fission rate SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB A new measurement-based method has been developed to determine the photofission contribution to measured responses of fission reactions in a mixed radiation field of neutrons and photons. Using this method, reliable upper and lower bounds can be established for the photofission contributions. Knowledge of the photon energy spectrum and the photofission cross sections is not required. The method involves the measurement and calculation of spectral indices of a fission reaction relative to a reaction whose response does not include any photon contribution. The differential changes in the spectral indices are measured as well as calculated with and without a gamma-ray attenuator. The measurements include responses from both neutrons and photons, whereas the calculations include contributions from neutrons only. An equation is derived for the ratio of photofission rate to neutron-induced fission rate using the definitions of the spectral indices. From this equation, algebraic upper and lower bounds can be determined for the photofission contribution using a minimum and a maximum value for the mass attenuation coefficient of the gamma-attenuating material at all photon energies. The method was tested in the radiation field inside the Materials Dosimetry Reference Facility (MDRF), which is a National Institute of Standards and Technology reference neutron field operating at the Ford Nuclear Reactor at the University of Michigan. Established algebraic upper bounds for the photofission contributions to the Np-237 and U-238 fission reactions in the MDRF were found to overlap zero. Conservative statistical upper bounds were established at the la level of confidence, and these are 0.87% for the Np-237 fission reaction and 0.55% for the U-238 fission reaction. C1 NATL INST STAND & TECHNOL,IONIZING RADIAT DIV,GAITHERSBURG,MD 20899. RP Venkataraman, R (reprint author), UNIV MICHIGAN,DEPT NUCL ENGN,ANN ARBOR,MI 48109, USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD JUL PY 1997 VL 126 IS 3 BP 314 EP 323 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA XN257 UT WOS:A1997XN25700005 ER PT J AU Aeppli, G Broholm, C DiTusa, JF Hayden, SM Ito, T Lee, SH Mason, TE Mook, HA Oka, K Perring, TG Schroder, A Takagi, H Xu, G AF Aeppli, G Broholm, C DiTusa, JF Hayden, SM Ito, T Lee, SH Mason, TE Mook, HA Oka, K Perring, TG Schroder, A Takagi, H Xu, G TI Magnetic coherence in the transition metal oxides SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference / 45th Yamada Conference on Physics of Transition Metals (ICPTM 96) CY SEP 24-27, 1996 CL OSAKA, JAPAN SP Yamada Sci Fdn DE Kagome lattice; spin liquid; transition metal oxide ID SUPERCONDUCTING LA1.85SR0.15CUO4; NEUTRON-SCATTERING; SPIN FLUCTUATIONS; KAGOME LATTICE; HALDANE-GAP; EXCITATIONS; DYNAMICS; YBA2CU3O6+X; CHAIN; LA1.86SR0.14CUO4 AB We review neutron scattering experiments which address the coherence of the ground states of four transition metal oxides. The states considered include some which, at the qualitative level, can be described classically and others which require a quantum mechanical understanding. In the former category are the antiferromagnetism of YBa2Cu3O6.15, and the peculiar ground stale of the Kagome compound SrCr9pGa12-9pO19, which is neither an antiferromagnet nor a spin glass. The latter category contains the Haldane quantum spin liquid, seen very clearly in the linear-chain compound Y2BaNiO5, and the superconducting slate of La1.86Sr0.14CuO4. C1 JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. UNIV BRISTOL,HH WILLS PHYS LAB,BRISTOL BS8 1TL,AVON,ENGLAND. ELECTROTECH LAB,TSUKUBA,IBARAKI 305,JAPAN. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV TORONTO,DEPT PHYS,TORONTO,ON M5S 1A7,CANADA. RUTHERFORD APPLETON LAB,ISIS FACIL,DIDCOT OX11 0QX,OXON,ENGLAND. RISO NATL LAB,DEPT SOLID STATE PHYS,DK-4000 ROSKILDE,DENMARK. UNIV TOKYO,ISSP,TOKYO 106,JAPAN. NIST,GAITHERSBURG,MD 20899. RP Aeppli, G (reprint author), NEC RES INST,4 INDEPENDENCE WAY,PRINCETON,NJ 08540, USA. RI Broholm, Collin/E-8228-2011; Hayden, Stephen/F-4162-2011; Xu, Guangyong/A-8707-2010; Takagi, Hidenori/B-2935-2010; Mason, Thomas/M-5809-2014 OI Broholm, Collin/0000-0002-1569-9892; Hayden, Stephen/0000-0002-3209-027X; Xu, Guangyong/0000-0003-1441-8275; Mason, Thomas/0000-0003-1880-3971 NR 28 TC 0 Z9 0 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUL PY 1997 VL 237 BP 30 EP 35 DI 10.1016/S0921-4526(97)00035-5 PG 6 WC Physics, Condensed Matter SC Physics GA XM233 UT WOS:A1997XM23300013 ER PT J AU Neuman, JA Cooper, J Gallagher, A AF Neuman, JA Cooper, J Gallagher, A TI Velocity dependence of energy pooling collisions in strontium SO PHYSICAL REVIEW A LA English DT Article ID CROSS-SECTIONS; ATOMS; SR AB The threshold behavior of the cross section of an endothermic energy pooling reaction is investigated. Zn a vapor cell experiment, pulsed; excitation followed by delayed fluorescence detection narrows the transverse velocity distribution df colliding pairs of laser-excited strontium atoms in the 5s5p P-3(1) level, and laser detuning establishes the collision velocity in the direction of counterpropagating laser-beams. A probe laser detects the excited-state collision product of the endothermic 5s5p 3P1 + 5s5p P-3(1) --> 5s6s S-1(0) + 5s(2 1)S(0) reaction. The cross section rises steeply at threshold and is nearly flat for 1.2-2 times the threshold energy. This behavior can be partly explained by the shape of the molecular potential curve of the collisionally produced state. From the measured 1.1 x 10(-12) cm(3) S-1 thermally averaged rate coefficient, the above-threshold cross section is found to be approximately 6 x 10(-17) cm(2). The thermally averaged rate coefficient for the highly exothermic energy pooling reaction 5s5p P-3(1) + 5s5p P-3(1) --> 5s5p P-1(1) + 5s(2 1)S(0) is also reported and measured to be 1.1 x 10(-10) cm(3) s(-1). The cross section for this exothermic reaction is found to be nearly independent of collision velocity. C1 UNIV COLORADO,BOULDER,CO 80309. RP Neuman, JA (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. RI Neuman, Andy/A-1393-2009 OI Neuman, Andy/0000-0002-3986-1727 NR 25 TC 3 Z9 3 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1997 VL 56 IS 1 BP 432 EP 442 DI 10.1103/PhysRevA.56.432 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XL645 UT WOS:A1997XL64500052 ER PT J AU Dodd, RJ Burnett, K Edwards, M Clark, CW AF Dodd, RJ Burnett, K Edwards, M Clark, CW TI Excitation spectroscopy of vortex states in dilute Bose-Einstein condensed gases SO PHYSICAL REVIEW A LA English DT Article ID ATOMS AB We apply linear-response analysis to the Gross-Pitaevskii equation to obtain the excitation frequencies of a Bose-Einstein condensate in a vortex state, and apply it to a system of rubidium atoms confined in a time-averaged orbiting potential trap. The excitation frequencies of a vortex differ significantly from those of the ground state, and may therefore be used to obtain a spectroscopic signature of the presence of a vortex state. C1 UNIV OXFORD,DEPT PHYS,CLARENDON LAB,OXFORD OX1 3PU,ENGLAND. GEORGIA SO UNIV,DEPT PHYS,STATESBORO,GA 30460. US DEPT COMMERCE,NIST,DIV ELECTRON & OPT PHYS,GAITHERSBURG,MD 20899. US DEPT COMMERCE,NIST,PHYS LAB,GAITHERSBURG,MD 20899. RP Dodd, RJ (reprint author), UNIV MARYLAND,INST PHYS SCI & TECHNOL,COLLEGE PK,MD 20742, USA. RI Clark, Charles/A-8594-2009; OI Clark, Charles/0000-0001-8724-9885; Edwards, Mark/0000-0002-3149-2402 NR 27 TC 114 Z9 115 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1997 VL 56 IS 1 BP 587 EP 590 DI 10.1103/PhysRevA.56.587 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XL645 UT WOS:A1997XL64500069 ER PT J AU Sachidanandam, R Yildirim, T Harris, AB Aharony, A EntinWohlman, O AF Sachidanandam, R Yildirim, T Harris, AB Aharony, A EntinWohlman, O TI Single-ion anisotropy, crystal-field effects, spin reorientation transitions, and spin waves in R2CuO4 (R=Nd, Pr, and Sm) SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC PHASE-TRANSITIONS; NEUTRON-SCATTERING; HEISENBERG-ANTIFERROMAGNET; ND2CUO4; PR2CUO4; LA2CUO4; CU; EXCITATIONS; EXCHANGE; COPPER AB We report a detailed study of single-ion anisotropy and crystal-field effects in rare-earth cuprates R2CuO4 (R=Nd Pr, and Sm). It is found that most of the magnetic properties are mainly due to the coupling between the copper and rare-earth magnetic subsystem which exhibits a large single-ion anisotropy. This anisotropy prefers ordering of rare-earth moments along [100] for R = Pr and Nd and along [001] for X = Sm. Combined with a pseudodipolar interaction arising from the anisotropy of the R-Cu exchange, we can explain the magnetic structures of these materials. The spin reorientation transitions in Nd2CuO4 can be explained in terms of a competition between various interplanar interactions which arises because of the rapid temperature dependence of the Nd moment below about 100 K. Finally we introduce a simple two-dimensional model for the Nd spin-wave spectrum. For zero wave vector, this model gives two optical modes involving Cu spins whose temperature-dependent energies agree with experimental results and an acoustic mode whose energy is predicted to be of order root 2k(4) Delta approximate to 5 mu eV, where k(4) is the fourfold in-plane anisotropy constant and Delta is the Nd doublet splitting. C1 UNIV MARYLAND, COLLEGE PK, MD 20742 USA. NIST, GAITHERSBURG, MD 20899 USA. UNIV PENN, DEPT PHYS, PHILADELPHIA, PA 19104 USA. RP TEL AVIV UNIV, RAYMOND & BEVERLY SACKLER FAC EXACT SCI, SCH PHYS & ASTRON, IL-69978 TEL AVIV, ISRAEL. RI yildirim, taner/A-1290-2009; ENTIN, ORA/F-1114-2012; harris, A Brooks/C-8640-2013 NR 61 TC 79 Z9 80 U1 1 U2 15 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1997 VL 56 IS 1 BP 260 EP 286 DI 10.1103/PhysRevB.56.260 PG 27 WC Physics, Condensed Matter SC Physics GA XJ272 UT WOS:A1997XJ27200052 ER PT J AU Sobolewski, MA AF Sobolewski, MA TI Dynamic model of the radio-frequency plasma sheath in a highly asymmetric discharge cell SO PHYSICAL REVIEW E LA English DT Article ID SECONDARY-ELECTRON EMISSION; CAPACITIVE RF SHEATH; PARALLEL-PLATE; LANGMUIR PROBE; ARGON; TRANSITION; ALUMINUM; ENERGY; ION AB A self-consistent fluid model for the radio-frequency sheath at the powered electrode of a highly asymmetric discharge cell is developed and solved. The model assumes time-independent ion motion and inertialess electrons. The voltage on the powered electrode, assumed to be sinusoidal, is shared between the powered sheath and a series resistance that represents the remainder of the discharge. The model includes ion collisions, sheath conduction currents, and secondary electron emission from the electrode surface. Model results are compared with previous sheath models and with experiment. Current wave forms predicted by the model closely resemble the nonsinusoidal current wave forms measured in highly asymmetric cells. The model accurately predicts the shape of sheath voltage wave forms, but not their de components. The magnitudes and phases of sheath impedances predicted by the model agree with experimental measurements performed in argon discharges at pressures of 4.0-133 Pa. RP Sobolewski, MA (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 22 TC 27 Z9 27 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUL PY 1997 VL 56 IS 1 BP 1001 EP 1011 DI 10.1103/PhysRevE.56.1001 PN B PG 11 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XM377 UT WOS:A1997XM37700057 ER PT J AU Holian, BL Thomson, R AF Holian, BL Thomson, R TI Crack limiting velocity SO PHYSICAL REVIEW E LA English DT Article ID FRACTURE; DYNAMICS AB We address the question of how a dynamic crack can approach zero velocity. Continuum theories usually do not explicitly include the radiation of energy away from the crack tip. We show that its inclusion leads to the prediction of crack velocity that increases smoothly (though sharply) from zero. We then connect an older, simple model of crack propagation (''atoms on rails'') to a recently proposed single-particle model and show how the disappearance of lattice trapping leads to a smooth low-velocity limit. C1 NATL INST STAND & TECHNOL,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899. RP Holian, BL (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 16 TC 4 Z9 4 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUL PY 1997 VL 56 IS 1 BP 1071 EP 1079 DI 10.1103/PhysRevE.56.1071 PN B PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XM377 UT WOS:A1997XM37700065 ER PT J AU Anderson, DM McFadden, GB AF Anderson, DM McFadden, GB TI A diffuse-interface description of internal waves in a near-critical fluid SO PHYSICS OF FLUIDS LA English DT Article ID LIQUID CRITICAL-POINT; PHASE-FIELD MODELS; SHEAR-FLOW; SOLIDIFICATION; EQUATIONS; GROWTH AB We present a diffuse-interface treatment of the internal gravity waves which have been observed experimentally by Berg et al. in xenon near its thermodynamic critical point. The results are compared with theoretical predictions by Berg et al. that were obtained using separate models above and below the critical temperature T-c. The diffuse-interface model applies both above and below T-c, and is formulated by using the density as an order parameter. The diffuse interface is represented as a transition zone of rapid but smooth density variation in the model, and density gradients appear in a capillary tensor, or Korteweg stress term, in the momentum equation. We obtain static density profiles, compute internal wave frequencies and compare with the experimental data and theoretical results of Berg et al. both above and below the critical temperature. The results reveal a singularity in the diffuse-interface model in the limit of incompressible perturbations. RP Anderson, DM (reprint author), NIST,DIV MATH & COMP SCI,GAITHERSBURG,MD 20899, USA. RI McFadden, Geoffrey/A-7920-2008 OI McFadden, Geoffrey/0000-0001-6723-2103 NR 55 TC 32 Z9 32 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUL PY 1997 VL 9 IS 7 BP 1870 EP 1879 DI 10.1063/1.869309 PG 10 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA XH287 UT WOS:A1997XH28700004 ER PT J AU Weinstock, J AF Weinstock, J TI Theory for the off-diagonal element of dissipation in homogeneous cheer turbulence SO PHYSICS OF FLUIDS LA English DT Article ID LOW-REYNOLDS-NUMBER; SHEAR-FLOW; CHANNEL FLOW; STRESS; CLOSURE AB The off-diagonal element, epsilon(12), Of the energy dissipation rate tensor is calculated from straightforward spectral considerations. The derivation is for homogeneous shear flows. Account is taken of the difference between energy spectra and stress spectra, and the dissipation range of the spectra is taken from recent high-resolution numerical simulations. Emphasized, is the theoretically derived power law describing the decrease of epsilon(12)/epsilon With increasing Reynolds number at large Reynolds number. For moderate Reynolds number, the theoretical epsilon(12)/epsilon is compared with numerical simulations. For large Reynolds number, the theory implies local isotropy. RP Weinstock, J (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 18 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUL PY 1997 VL 9 IS 7 BP 2171 EP 2173 DI 10.1063/1.869340 PG 3 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA XH287 UT WOS:A1997XH28700033 ER PT J AU Estler, WT Phillips, SD Borchardt, B Hopp, T Levenson, M Eberhardt, K McClain, M Shen, Y Zhang, X AF Estler, WT Phillips, SD Borchardt, B Hopp, T Levenson, M Eberhardt, K McClain, M Shen, Y Zhang, X TI Practical aspects of touch-trigger probe error compensation SO PRECISION ENGINEERING-JOURNAL OF THE AMERICAN SOCIETY FOR PRECISION ENGINEERING LA English DT Article DE coordinate measuring machines; dimensional metrology; error correction; modeling; probes; touch-trigger probes AB We present extensions to our prior work in modeling and correcting for pretravel variation errors in kinematic seat touch-trigger coordinate measuring machine (CMM) probes with straight styli. A simple correction term is shown to account for a range of probe asymmetries quantitatively, leading to improved error compensation. We also demonstrate probe lobing correction for constrained fits to small datasets, illustrating practical examples for both CMM and machine tool probes. Finally, we discuss statistical and uncertainty issues and demonstrate the effectiveness of the model with actual measurement data. (C) 1997 Elsevier Science Inc. C1 NIST, Div Precis Engn, Gaithersburg, MD 20899 USA. RP Estler, WT (reprint author), NIST, Div Precis Engn, Metrol B113, Gaithersburg, MD 20899 USA. NR 3 TC 19 Z9 19 U1 1 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0141-6359 J9 PRECIS ENG JI Precis. Eng.-J. Am. Soc. Precis. Eng. PD JUL PY 1997 VL 21 IS 1 BP 1 EP 17 DI 10.1016/S0141-6359(97)00062-7 PG 17 WC Engineering, Multidisciplinary; Engineering, Manufacturing; Nanoscience & Nanotechnology; Instruments & Instrumentation SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation GA YP197 UT WOS:000071252300001 ER PT J AU Conkright, RO Davies, K Musman, S AF Conkright, RO Davies, K Musman, S TI Comparisons of ionospheric total electron contents made at Boulder, Colorado, using the global positioning system SO RADIO SCIENCE LA English DT Article AB We discuss two different methods of deriving ionosphere total electron content (TEC) from observations of Global Positioning Satellites (GPS) at Boulder, Colorado. In the first method, data from the National Institute of Standards and Technology Ionospheric Monitoring System (NIMS) are examined for the period of January 1994 to January 1995. In the second method, carrier phase models are constructed for four days in January 1995 and at two stations near Boulder. Both methods are compared with Faraday rotation values. Smoothed NIMS observations are an adequate representation for smoothed TEC variation during the day. Carrier phase models show good agreement with Faraday rotation and consistency between nearby receivers. C1 NOAA,SPACE ENVIRONM LAB,BOULDER,CO 80303. NOAA,GEOSCI LAB,SILVER SPRING,MD 20910. RP Conkright, RO (reprint author), NOAA,NATL GEOPHYS DATA CTR,325 BROADWAY,BOULDER,CO 80303, USA. NR 10 TC 7 Z9 7 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1997 VL 32 IS 4 BP 1491 EP 1497 DI 10.1029/97RS00579 PG 7 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA XM795 UT WOS:A1997XM79500014 ER PT J AU Filla, BJ AF Filla, BJ TI A steady-state high-temperature apparatus for measuring thermal conductivity of ceramics SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A one-sided very-high-temperature guarded hot plate has been built to measure thermal conductivity of monolithic ceramics, ceramic composites, thermal barrier coatings, functional graded materials, and high-temperature metal alloys. It is an absolute, steady-state measurement. device with an operational temperature range of 400-1400 K. Measurements are made in an atmosphere of low-pressure helium. Specimens examined in this apparatus are 70 mm in diameter, with thicknesses ranging between 1 and 8 mm. Optimal specimen thermal conductivities fall in the range of 0.5-30 W/(mK). Internal heated components are composed entirely of high-purity aluminum oxide, boron nitride, beryllium oxide, and fibrous alumina insulation board. Pure nickel and thermocouple-grade platinum-based alloys are the only metals used in the system. Apparatus design, modeling, and operation are described, along with the methods of data analysis that are unique to this system. An analysis of measurement uncertainty yields a combined measurement uncertainty of +/-5%. Experimental measurements on several materials are presented to illustrate the precision and bias of the apparatus. RP Filla, BJ (reprint author), NATL INST STAND & TECHNOL,DIV MAT RELIABIL,BOULDER,CO 80303, USA. NR 18 TC 23 Z9 24 U1 3 U2 23 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 1997 VL 68 IS 7 BP 2822 EP 2829 DI 10.1063/1.1148202 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA XL851 UT WOS:A1997XL85100030 ER PT J AU Bruno, TJ Mayrath, JE AF Bruno, TJ Mayrath, JE TI Concatenated gas saturation vapor pressure apparatus SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB This article presents a gas saturation vapor pressure apparatus capable of simultaneous vapor pressure measurements on a total of up to six samples. The apparatus operates at 280-365 K and total pressures of 100-200 kPa. The apparatus features a series of alternating saturators and adsorbers allowing multiple vapor pressure measurements to be made with a single carrier gas stream. Total carrier gas flow is derived from mass measurements. The apparatus provides multiple simultaneous vapor pressure measurements for series or families of compounds allowing correlations of physical properties within the families. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,PHYS & CHEM PROPERTIES DIV,BOULDER,CO 80303. NR 15 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 1997 VL 68 IS 7 BP 2864 EP 2870 DI 10.1063/1.1148209 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA XL851 UT WOS:A1997XL85100037 ER PT J AU Sorathia, U Lyon, R OHlemiller, T Grenier, A AF Sorathia, U Lyon, R OHlemiller, T Grenier, A TI A review of fire test methods and criteria for composites SO SAMPE JOURNAL LA English DT Editorial Material C1 FED AVIAT ADMIN,WASHINGTON,DC 20591. UNIV COLORADO,NIST,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. RP Sorathia, U (reprint author), USN,CTR SURFACE WARFARE,CARDEROCK DIV,WASHINGTON,DC 20350, USA. NR 26 TC 19 Z9 19 U1 0 U2 2 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0091-1062 J9 SAMPE J JI Sampe J. PD JUL-AUG PY 1997 VL 33 IS 4 BP 23 EP 31 PG 9 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA XK810 UT WOS:A1997XK81000004 ER PT J AU Gilman, JW Kashiwagi, T Lichtenhan, JD AF Gilman, JW Kashiwagi, T Lichtenhan, JD TI Nanocomposites: A revolutionary new flame retardant approach SO SAMPE JOURNAL LA English DT Article ID NYLON 6-CLAY HYBRID; POLYMER AB To evaluate the feasibility of controlling polymer flammability via a nanocomposite approach, we have examined the flammability properties of nylon-6 clay-nanocomposites, The fire retardant (FR) properties of this new class of materials, organic-inorganic nanocomposites, are reported. The cone calorimeter data show that the peak heat release rate (HRR), the most important parameter for predicting fire hazard, is reduced by 63 percent in a nylon-6 clay-nanocomposite containing a clay mass fraction of only five percent. Not only is this a very efficient FR system, hut, it does not have the usual drawbacks associated with other FR additives, That is, the physical properties are not degraded by the additive (clay), instead they are greatly improved. Furthermore, this system does not increase the carbon monoxide or soot produced during the combustion, as many commercial fire retardants do. The nanocomposite structure appears to enhance the performance of the char through reinforcement of the char layer. indeed, transmission electron microscopy (TEM) of a section of Che combustion char from the nylon-6 clay-nanocomposite (five percent) shows a multilayered silicate structure. This layer may act as an insulator and a mass transport barrier slowing the escape of the volatile products generated as the nylon-6 decomposes. C1 PHILLIPS LAB,EDWARDS AFB,CA. RP Gilman, JW (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 17 TC 350 Z9 378 U1 3 U2 66 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0091-1062 J9 SAMPE J JI Sampe J. PD JUL-AUG PY 1997 VL 33 IS 4 BP 40 EP 46 PG 7 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA XK810 UT WOS:A1997XK81000007 ER PT J AU Wu, CC Dryer, M AF Wu, CC Dryer, M TI Three-dimensional mhd simulation of interplanetary magnetic field changes at 1 AU caused by a simulated solar disturbance and a tilted heliospheric current plasma sheet SO SOLAR PHYSICS LA English DT Article ID STORMS; ORIGIN; WIND AB A fully three-dimensional (3D), time-dependent, MHD interplanetary model has been used, for the first time, to study the relationship between one form of solar activity and transient variations of the north-south component, B-z, of the interplanetary magnetic field (IMF) at 1 AU during the active period of a representative solar cycle. Four cases of initial steady-state solar wind conditions, with different tilt angles of the heliospheric current sheet/plasma sheet (HCS/HPS) which is known to be inclined at solar maximum, are used to study the relationship between the location of solar activity and transient variations of the north-south IMF B-z component at 1 AU. We simulated the initialization of the disturbance as a density pulse at different locations near the solar surface for each case of initial steady-state condition and observed the simulated IMF evolution of B-theta (= -B-z) at 1 AU. The results show that, for a given density pulse, the orientation of the corresponding transient variation of B-z has a strong relationship to the location of the density pulse and the initial conditions of the IMF. A recipe for prediction of the initial B-z turning direction is also presented in this study. In previous studies that used this recipe with only a flat HCS/HPS that was coincident with the solar equatorial plane, we found a prediction accuracy of 83% from a data set of 73 events during solar maximum. The present study that incorporates more realistic HCS/HPS tilt angles confirms the earlier work. Our study leads us to suggest that significant B-z values, associated with substantial post-shock temporal periods of hours at 1 AU, could be achieved if large energies (say, 10(32)-10(33) erg) were released at the Sun in a flare or helmet de-stabilization process. C1 NOAA,SPACE ENVIRONM CTR,BOULDER,CO 80303. RP Wu, CC (reprint author), NATL CENT UNIV,INST SPACE SCI,CHUNGLI 32054,TAIWAN. NR 22 TC 15 Z9 15 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JUL PY 1997 VL 173 IS 2 BP 391 EP 408 DI 10.1023/A:1004929802499 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XQ472 UT WOS:A1997XQ47200014 ER PT J AU Martin, A OSullivan, P Mathewson, A Suehle, JS Chaparala, P AF Martin, A OSullivan, P Mathewson, A Suehle, JS Chaparala, P TI Investigation of the influence of ramped voltage stress on intrinsic t(bd) of MOS gate oxides SO SOLID-STATE ELECTRONICS LA English DT Article ID THIN THERMAL OXIDES; DIELECTRIC-BREAKDOWN; SILICON AB This study investigates the influence of a pre-stressing ramped voltage stress prior to a constant voltage stress on the time to breakdown. Constant voltage stress and combined ramped/constant voltage stress measurements were performed on six MOS gate oxide thicknesses. The time to breakdown distributions were compared and an increase of the time to breakdown for pre-stressed oxides was observed in some cases. A further analysis of the current-time characteristics gave conclusions about the trapping properties of the oxide. It was found that the initial positive charge build up in the oxide is an important indicator for degradation which must be considered for highly accelerated reliability measurements on pre-stressed oxides. Since common understanding of oxide breakdown and models for breakdown mechanisms cannot describe all of the experimental results a qualitative model is proposed. (C) 1997 Elsevier Science Ltd. C1 NIST,GAITHERSBURG,MD 20899. NATL SEMICOND CORP,SANTA CLARA,CA 95052. RP Martin, A (reprint author), NATL UNIV IRELAND UNIV COLL CORK,NATL MICROELECT RES CTR,PROSPECT ROW,CORK,IRELAND. OI Mathewson, Alan/0000-0003-4687-7812 NR 17 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD JUL PY 1997 VL 41 IS 7 BP 1013 EP 1020 DI 10.1016/S0038-1101(97)00015-4 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA XJ055 UT WOS:A1997XJ05500015 ER PT J AU McInnes, L Covert, D Baker, B AF McInnes, L Covert, D Baker, B TI The number of sea-salt, sulfate, and carbonaceous particles in the marine atmosphere: EM measurements consistent with the ambient size distribution SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID MICROPROBE MASS ANALYSIS; AEROSOL-PARTICLES; BOUNDARY-LAYER; SPECTROMETRY; CLOUDS AB To evaluate the number of sea-salt, sulfate, and carbonaceous particles associated with the fine and coarse mode aerosol in the marine boundary layer and from the marine/continental interface, the elemental composition of individual aerosol particles was determined with EM. Samples were collected from the Pacific marine boundary layer during a research cruise along 140 degrees W from the southern to northern hemisphere, and from a coastal station in NW Washington. Consistently, the most dominant aerosol types found were ammonium sulfate and acidic sulfate comprising 52 to 96% of the total number at a median diameter of 0.14 mu m. Sea-salt particles were 4 to 13% of the total number, with modes at 0.2 and 0.6 mu m. Carbonaceous particles, mostly as organic compounds, made up the remainder of the submicrometer aerosol at a few % to as much as 31% of the total number for continentally influenced periods. Silica-rich minerals and potassium and calcium salts were observed during such periods, representing a measurable, but small fraction of the total number. Sea-salt particles were 86 to 100% of the number of supermicrometer particles with a mass median diameter of 1.5 mu m. A less abundant, and variable fraction of mineral particles made up the remainder of the coarse aerosol number concentration identified primarily as aluminosilicates, mass median diameter of 0.9 mu m. Very little soot was observed in either the coarse or fine mode. Particle number concentrations were consistently low and airmass trajectories suggest the air originated over the open ocean for the majority of the sampling periods. Overall, normalized EM distributions agreed fairly well with in-situ measurements of the aerosol size distribution. C1 UNIV WASHINGTON,DEPT ATMOSPHER SCI,SEATTLE,WA 98195. UNIV COLORADO,DEPT CHEM,BOULDER,CO 80309. RP McInnes, L (reprint author), NOAA,CLIMATE MONITORING & DIAGNOST LAB,RECG1,325 BROADWAY,BOULDER,CO 80303, USA. NR 29 TC 35 Z9 36 U1 1 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD JUL PY 1997 VL 49 IS 3 BP 300 EP 313 DI 10.1034/j.1600-0889.49.issue3.6.x PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XQ009 UT WOS:A1997XQ00900006 ER PT J AU Fitzhugh, GR Nixon, SW Ahrenholz, DW Rice, JA AF Fitzhugh, GR Nixon, SW Ahrenholz, DW Rice, JA TI Temperature effects on otolith microstructure and birth month estimation from otolith increment patterns in Atlantic menhaden SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID SALMON ONCORHYNCHUS-TSHAWYTSCHA; BREVOORTIA-TYRANNUS; NORTH-CAROLINA; GROWTH INCREMENTS; RECRUITMENT; SURVIVAL; LARVAE; REEF; DAMSELFISH; DURATION AB We demonstrate temperature-influenced increment spacing in the sagittal otoliths of juvenile Atlantic menhaden Brevoortia tyrannus reared at different temperatures and describe otolith increment patterns from wild juveniles born in different months. Tank-reared individuals completed metamorphosis a month earlier at 25 degrees C than at ambient temperatures (10-14 degrees C). We identified several patterns from the sectioned otoliths, including reduced time to metamorphosis, faster transition to the juvenile stage, and increased increment spacing after onset of metamorphosis for those individuals exposed to warmer temperatures. For wild individuals that could be accurately aged, mean otolith increment spacing in the zone from 70 to 80 increments increased 1-2 mu m for fish born in November and December to more than 3 mu m for fish born in February. The increase in increment spacing is consistent with the arrival of individuals across seasonally warming temperatures in the estuary. A discriminant analysis based on otolith increment spacing and metamorphic patterns successfully classified birth month for 59-100% (65% overall) of Atlantic menhaden spawned between November-February. This approach is being developed ultimately to identify the birth month of wild Atlantic menhaden adults in order to test fur differential survival among cohorts born in different months that recruit to the fishery. C1 NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,BEAUFORT LAB,BEAUFORT,NC 28516. RP Fitzhugh, GR (reprint author), N CAROLINA STATE UNIV,DEPT ZOOL,BOX 7617,RALEIGH,NC 27695, USA. NR 38 TC 13 Z9 15 U1 1 U2 3 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD JUL PY 1997 VL 126 IS 4 BP 579 EP 593 DI 10.1577/1548-8659(1997)126<0579:TEOOMA>2.3.CO;2 PG 15 WC Fisheries SC Fisheries GA XU266 UT WOS:A1997XU26600003 ER PT J AU Ying, TN Hsu, SM AF Ying, TN Hsu, SM TI Effect of friction on subsurface strain distribution of steel SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 50th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 14-19, 1995 CL CHICAGO, IL SP Soc Tribologists & Lubricat Engineers DE wear; steel; contact mechanics; stress analysis; friction ID CONTACT; WEAR; WORN AB The effect of friction on the subsurface strain distribution of a 1018 steel is investigated using a two-ball collision apparatus. After the two balls collided with each other, the friction level was recorded and cross sections were made of the balls to examine the surface and subsurface damage from the collision. Various lubricants were used to control the level of friction. At frictional levels higher than 0.4, the strain angles as measured by the grain alignment method are almost parallel to the surface and the depth of the deformed layer is very shallow. At lower frictional levels, the strain angles are small and the depth of the deformed layer is deep. A computer program was developed to map the subsurface gain shape change after each collision. The grain shape reflects the shear strain angle. Results suggest there was a definite relationship between the friction and the subsurface shear strain angles. RP Ying, TN (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 11 TC 3 Z9 3 U1 1 U2 1 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 1997 VL 40 IS 3 BP 429 EP 435 DI 10.1080/10402009708983677 PG 7 WC Engineering, Mechanical SC Engineering GA XR758 UT WOS:A1997XR75800005 ER PT J AU Michel, KH Copley, JRD AF Michel, KH Copley, JRD TI Orientational mode coupling, diffuse scattering, and the order-disorder phase transition in solid C-60 SO ZEITSCHRIFT FUR PHYSIK B-CONDENSED MATTER LA English DT Article ID X-RAY; TEMPERATURE MODIFICATION; MOLECULAR-STRUCTURE; CRYSTAL-STRUCTURE; ROOM-TEMPERATURE; SINGLE-CRYSTAL; C60; DYNAMICS; NEUTRON; FIELD AB We present a theory of the orientational dynamics of solid C-60 which takes into account the coupling of orientational modes belonging to various symmetries and manifolds. Mode coupling strongly enhances the transition temperature and the first order character of the structural phase change to the low temperature

structure. An improved parametrization of the intermolecular potential leads to a transition temperature which is close to the experimental value and to a satisfactory description of the crystal field. The diffuse scattering in the disordered phase is investigated and the interplay of different symmetries is discussed. The theory provides a consistent description of a broad range of experimental properties. C1 NATL INST STAND & TECHNOL, MAT SCI & ENGN LAB, GAITHERSBURG, MD 20899 USA. RP Michel, KH (reprint author), UNIV INSTELLING ANTWERP, DEPT PHYS, B-2610 WILRIJK, BELGIUM. NR 49 TC 21 Z9 21 U1 0 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0722-3277 J9 Z PHYS B CON MAT JI Z. Phys. B-Condens. Mat. PD JUL PY 1997 VL 103 IS 3-4 BP 369 EP 376 DI 10.1007/s002570050390 PG 8 WC Physics, Condensed Matter SC Physics GA XL521 UT WOS:A1997XL52100005 ER PT J AU Lee, C Gido, SP Pitsikalis, M Mays, JW Tan, NB Trevino, SF Hadjichristidis, N AF Lee, C Gido, SP Pitsikalis, M Mays, JW Tan, NB Trevino, SF Hadjichristidis, N TI Asymmetric single graft block copolymers: Effect of molecular architecture on morphology SO MACROMOLECULES LA English DT Article ID 3-MIKTOARM AB This paper reports on the synthesis and morphological characterization of graft, block copolymers in which a single polystyrene (PS) arm was grafted at an asymmetric position along a polyisoprene (PI) backbone. These materials represent a model series of asymmetric simple graft (ASG) block copolymer structures. The synthesis of these materials was carried out with methods developed for three-arm ''miktoarm'' star copolymers using anionic polymerization high-vacuum techniques with cholorosilane linking agents. The three arms were two polyisoprene blocks with different degrees of polymerization and one deuterated polystyrene block, which formed an asymmetric simple graft structure (ASG). Molecular characterization was performed using size exclusion chromatography (SEC) with refractive index and UV detection, membrane osmometry, and low-angle laser light scattering. These techniques confirmed that the materials exhibited narrow molecular weight distributions and low compositional heterogeneity. The morphologies formed by these samples were characterized using transmission electron microscopy (TEM) and small-angle neutron scattering(SANS). The ASG structures were compared with structures formed by Linear diblock copolymers and other samples having miktoarm structures, like I2S (symmetric simple graft with PI backbone and one PS branch grafted from the middle) and I3S (three equal PI arms and one PS arm). Comparisons of the morphologies formed and their dimensions indicated that the chain stretching and lateral crowding due to the miktoarm architecture was partially alleviated by the different lengths of PI blocks in ASG. C1 UNIV MASSACHUSETTS,DEPT POLYMER SCI & ENGN,WM KECK ELECTRON MICROSCOPY LAB,AMHERST,MA 01003. UNIV ALABAMA,DEPT CHEM,BIRMINGHAM,AL 35294. USA,RES LAB,POLYMERS RES BRANCH,ABERDEEN PROVING GROUND,MD 21100. NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. INST ELECT STRUCT & LASER,GR-71110 IRAKLION,CRETE,GREECE. UNIV ATHENS,DEPT CHEM,GR-15771 PANEPISTIMIOPOLI,GREECE. NR 19 TC 45 Z9 45 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 30 PY 1997 VL 30 IS 13 BP 3732 EP 3738 DI 10.1021/ma970172p PG 7 WC Polymer Science SC Polymer Science GA XH723 UT WOS:A1997XH72300003 ER PT J AU Yildirim, T Gehring, PM Neumann, DA Eaton, PE Emrick, T AF Yildirim, T Gehring, PM Neumann, DA Eaton, PE Emrick, T TI Unusual structure, phase transition, and dynamics of solid cubane SO PHYSICAL REVIEW LETTERS LA English DT Article ID ORIENTATIONAL ORDERING TRANSITION; SCATTERING; DISORDER; CRYSTALS; MODES; C-60 AB The cubic structure of the cubane molecule, C8H8, gives rise to many unusual properties in the solid stale. X-ray powder diffraction measurements of solid cubane reveal a large thermal expansion. followed by a strong first-order phase transition at 394 K from an orientationally ordered phase () to a noncubic orientationally disordered phase ( or R3m). The resulting volume expansion is 5.4%. Model calculations predict the correct low- and high-temperature phases. The orientational potential in the disordered phase resembles a rounded square well over a large angular range. Cubane thus represents an ideal example of a system with large-amplitude collective motions. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637. RP Yildirim, T (reprint author), UNIV MARYLAND,COLLEGE PK,MD 20742, USA. RI yildirim, taner/A-1290-2009; OI Gehring, Peter/0000-0002-9236-2046 NR 22 TC 42 Z9 43 U1 0 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 30 PY 1997 VL 78 IS 26 BP 4938 EP 4941 DI 10.1103/PhysRevLett.78.4938 PG 4 WC Physics, Multidisciplinary SC Physics GA XH038 UT WOS:A1997XH03800012 ER PT J AU Ratton, L Kunt, T McAvoy, T Fuja, T Cavicchi, R Semancik, S AF Ratton, L Kunt, T McAvoy, T Fuja, T Cavicchi, R Semancik, S TI A comparative study of signal processing techniques for clustering microsensor data (a first step towards an artificial nose) SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE artificial nose; signal processing; Haar wavelet transform; olfactory model; gas sensing; microsensor; micro-hotplates; tin oxide ID IDENTIFICATION CAPABILITY; PATTERN-RECOGNITION; ARRAY; GAS AB Microsensor technology has progressed to the point where it is now feasible to place several hundred sensors on a computer chip. Such a sensor array can potentially be used in many applications including detecting hazardous chemical emissions, food processsing, and fire detection. This paper addresses an important aspect involved in microsensor applications, namely how the sensor signals are processed. The problem treated involves classifying whether a sensed signal is generated by one of four chemicals. Two broad approaches to processing the sensor signals are discussed, one based on classical signal processing approaches, and one based on a model of how the olfactory system in animals functions. The classical approaches used include: Gram Schmidt orthogonalization, fast Fourier transforms, and Haar wavelets. For the experimental signals treated, the classical approaches give superior results compared to those produced by the olfactory model. (C) 1997 Elsevier Science S.A. C1 UNIV MARYLAND, DEPT CHEM ENGN, SYST RES INST, COLLEGE PK, MD 20742 USA. NIST, CHEM SCI & TECHNOL LAB, GAITHERSBURG, MD 20899 USA. NR 22 TC 51 Z9 53 U1 1 U2 5 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD JUN 30 PY 1997 VL 41 IS 1-3 BP 105 EP 120 DI 10.1016/S0925-4005(97)80283-3 PG 16 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA XX079 UT WOS:A1997XX07900014 ER PT J AU Cooper, MJ DiezRojo, T Rogers, LJ Western, CM Ashfold, MNR Hudgens, JW AF Cooper, MJ DiezRojo, T Rogers, LJ Western, CM Ashfold, MNR Hudgens, JW TI Ion-pair states of the ClO radical observed by multiphoton ionisation spectroscopy SO CHEMICAL PHYSICS LETTERS LA English DT Article ID IONIZATION SPECTROSCOPY; ABSORPTION-SPECTRUM; CIO AB We present isotopically selected multiphoton ionisation spectra of the ClO radical following excitation in the wavelength range 276-261 nm, obtained using both a room-temperature sample and under the rotationally cold conditions in a pulsed molecular beam. In both cases high-resolution rotationally resolved spectra were obtained, with the 'cold' spectra showing discrete rovibrational bands. Analysis of the rotational structure leads to the identification of excited levels of ClO of (2) Pi symmetry resonant at the two-photon energy (72200-76200 cm(-1)). These we deduce to possess extended equilibrium bond lengths (R approximate to 2.4 Angstrom), and thus associate with One or more ion-pair states. Full interpretation of the observed spectra is complicated by the effects of additional wavelength-dependent intensity enhancements due to predissociated levels of the A(2) Pi state accidentally resonant at the energy of one absorbed photon. We report an isotopically resolved room-temperature 2 + 1 REMPI spectrum, involving a progression of vibrational levels of the previously documented C-2 Sigma(-) state of ClO. The observed C-X two-photon transitions are well reproduced using known spectroscopic constants. (C) 1997 Elsevier Science B.V. C1 NIST,CHEM & PHYS PROPERTIES DIV,GAITHERSBURG,MD 20899. RP Cooper, MJ (reprint author), UNIV BRISTOL,SCH CHEM,CANTOCKS CLOSE,BRISTOL BS8 1TS,AVON,ENGLAND. OI Western, Colin/0000-0002-8336-1690; ashfold, michael/0000-0001-5762-7048 NR 22 TC 15 Z9 15 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 27 PY 1997 VL 272 IS 3-4 BP 232 EP 238 DI 10.1016/S0009-2614(97)88014-1 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XH440 UT WOS:A1997XH44000015 ER PT J AU Hamilton, K AF Hamilton, K TI Observation of an ultraslow large-scale wave near the tropical tropopause SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID EQUATORIAL AB An analysis is made of very high resolution radiosonde data taken at seven western Pacific island stations during TOGA-COARE (Tropical Ocean-Global Atmosphere and Coupled Ocean-Atmosphere Response Experiment). Evidence is found for a wave near the tropopause with periods similar to 30-40 days and with very slow (similar to 3 m s(-1)) eastward propagation. This oscillation appears quite coherent across the region considered (a 37 degrees longitude spread). The oscillation has a short vertical wavelength (similar to 3 km) and is strongly attenuated above the tropopause and thus would be very hard to observe in either satellite data or conventional meteorological analyses. RP PRINCETON UNIV, GEOPHYS FLUID DYNAM LAB, NOAA, PRINCETON, NJ 08542 USA. NR 12 TC 2 Z9 2 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1997 VL 102 IS D12 BP 13457 EP 13464 DI 10.1029/97JD00486 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH196 UT WOS:A1997XH19600005 ER PT J AU Feingold, G Boers, R Stevens, B Cotton, WR AF Feingold, G Boers, R Stevens, B Cotton, WR TI A modeling study of the effect of drizzle on cloud optical depth and susceptibility SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; LARGE-EDDY SIMULATION; STRATOCUMULUS CLOUDS; WATER CLOUDS; ALBEDO; PRECIPITATION; RADIATION; ASTEX; TRANSITION; RADIOMETER AB This paper examines the impact of drop spectral broadening, generated by the collection process, on the optical depth, cloud albedo, and susceptibility of marine stratocumulus clouds. The results are arrived at using (1) the output from a Simple box model calculation of collection and (2) the output from an eddy-resolving model of stratocumulus clouds that explicitly represents the size distribution of the drops. It is shown that commonly used relationships for cloud optical properties developed for narrow spectra do not generally apply to spectra undergoing spectral broadening. The optical depth dependence on the drop number concentration to the one-third power is shown to be an overestimate of the optical depth when spectra broaden through collection. In addition, the cloud susceptibility dependence on drop number is shown to be larger for spectra experiencing broadening than for narrow spectra. C1 CSIRO, DIV ATMOSPHER RES, ASPENDALE, VIC 3195, AUSTRALIA. COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. COOPERAT INST RES ATMOSPHERE, BOULDER, CO 80303 USA. RP Feingold, G (reprint author), NOAA, ENVIRONM TECHNOL LAB, 325 BROADWAY, BOULDER, CO 80303 USA. RI Stevens, Bjorn/A-1757-2013; Feingold, Graham/B-6152-2009 OI Stevens, Bjorn/0000-0003-3795-0475; NR 31 TC 41 Z9 42 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1997 VL 102 IS D12 BP 13527 EP 13534 DI 10.1029/97JD00963 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH196 UT WOS:A1997XH19600012 ER PT J AU Post, MJ Grund, CJ Wang, DL Deshler, T AF Post, MJ Grund, CJ Wang, DL Deshler, T TI Evolution of Mount Pinatubo's aerosol size distributions over the continental United States: Two wavelength lidar retrievals and in situ measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BACKSCATTER MEASUREMENTS; PROFILES AB We use lidar measurements at wavelengths of 10.59 and 0.694 mu m, together with contemporaneous in situ measurements of aerosol size distribution width, to retrieve the time-height evolution of lognormal median radius and number density for stratospheric aerosols over the central United States during the hi-st two years after the eruption of Mount Pinatubo. Comparisons with the in situ measurements of median radius and number density are favorable only if the 10.59-mu m backscatter is doubled, indicating a calibration bias in NOAA's climatological data set. The time histories of lidar-retrieved parameters at lower altitudes indicate that material from a new source appeared in the stratospheric aerosol cloud in the fall of 1992, about 500 days after the eruption of Mount Pinatubo. C1 UNIV WYOMING, DEPT ATMOSPHER SCI, LARAMIE, WY 82071 USA. RP Post, MJ (reprint author), NOAA, ENVIRONM TECHNOL LAB, 325 BROADWAY, BOULDER, CO 80303 USA. NR 24 TC 2 Z9 2 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1997 VL 102 IS D12 BP 13535 EP 13542 DI 10.1029/97JD00644 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH196 UT WOS:A1997XH19600013 ER PT J AU Mach, DM Rust, WD AF Mach, DM Rust, WD TI Two-dimensional speed and optical risetime estimates for natural and triggered dart leaders SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LIGHTNING RETURN STROKES; PEAK CURRENT; ELECTROMAGNETIC-RADIATION; PROPAGATION; INTENSITY; VELOCITY; FLASHES; FLORIDA AB We report velocities, risetimes, and other optical measurements of a set of 35 natural and 26 triggered dart leaders. All of the dart leaders are from negative strokes. The data were taken with our return stroke velocity device mounted on the National Severe Storms Laboratory mobile laboratory. The average two-dimensional (2-D) speed for the natural leaders is 1.9 +/- 0.2 x 10(7) m s(-1), while the triggered dart leader average 2-D speed is 1.3 +/- 0.1 x 10(7) m s(-1). These two averages are significantly different. We find no significant change in the dart leader 2-D speed with height. The mean 10-90% optical risetime for the natural dart leaders is 2.6 +/- 0.4 mu s. The optical risetime is evaluated from short channel segments (length of 3.2 +/- 1.7 m) located within 100 m of the ground. The corresponding risetime for triggered leaders is 1.4 +/- 0.4 mu s. These averages are significantly different. We calculated an average dart leader head length of 35 +/- 5.4 m. We find no significant difference between natural and triggered dart leader head lengths. The channel traversed by the dart leader and before the return stroke is often bright enough to be detected by our instrument. We find that the ratio of the channel brightness after the dart leader head to the dart leader head is closer to unity for triggered dart leaders. We see no clear relationship between dart leader optical risetimes and subsequent return stroke peak transmission line model (TLM) current. We find that natural dart leader speeds are correlated with the return stroke peak TLM currents: the peak TLM current increases with increasing natural dart leader 2-D speed. We see no correlation between triggered dart leader speeds and subsequent return stroke peak TLM currents. At a given dart leader speed, natural return strokes will have smaller peak TLM currents. Overall, these results indicate that there are significant differences between natural and triggered dart leaders. C1 NOAA, ENVIRONM RES LAB, NATL SEVERE STORMS LAB, NORMAN, OK 73069 USA. RP Mach, DM (reprint author), GLOBAL HYDROL & CLIMATE CTR, EARTH SYST SCI LAB, 977 EXPLORER BLVD, HUNTSVILLE, AL 35806 USA. NR 30 TC 8 Z9 10 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1997 VL 102 IS D12 BP 13673 EP 13684 DI 10.1029/97JD00926 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH196 UT WOS:A1997XH19600025 ER PT J AU Cullather, RI Bromwich, DH Grumbine, RW AF Cullather, RI Bromwich, DH Grumbine, RW TI Validation of operational numerical analyses in Antarctic latitudes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article; Proceedings Paper CT XXIst General Assembly of the International-Union-of-Geodesy-and-Geophysics CY JUL 02-14, 1995 CL BOULDER, CO SP Int Union Geodesy & Geophys ID NATIONAL-METEOROLOGICAL-CENTER; KATABATIC WIND REGIME; SOUTHERN-HEMISPHERE; ECMWF ANALYSES; PRECIPITATION; SIMULATION; FORECASTS; OCEAN; CLIMATE; SYSTEM AB Available rawinsonde, automatic weather station (AWS), ship, and synthesized long-term observations are used to evaluate the Antarctic numerical analyses of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the U.S. National Centers for Environmental Prediction (NCEP) from 1985 to 1994. Twice-daily variations in the ECMWF surface pressure analyses compare closely with AWS units of the U.S. Antarctic Program and ship observations. The NCEP analyses lover the same period show substantial improvement, particularly during the period 1985-1990. Surface air temperatures and winds do not agree so closely, which may result from analyses error, the localized nature of the fields, or a combination. Validation of the analyses standard pressure level fields using available rawinsonde data reveal a general long-term decrease in RMS errors with time for both analyses. RMS errors in NCEP 200 hPa geopotential heights of over 200 geopotential meters (gpm) for central plateau stations are evident only prior to May 1986. However, a significant upward trend from 1989 to 1993 in geopotential height RMS differences is apparent at several levels. The ECMWF analyses are generally found to be superior and offer a reasonable depiction of the broadscale atmospheric circulation; however, deficiencies in midtropospheric temperatures and lower tropospheric winds are evident. Comparisons of ship data from individual cruises of the S.A. Agulhas and the RN Nathaniel B. Palmer to the numerical analyses reveal substantial agreement for pressure and temperature variables. Observations from the Nathaniel B. Palmer in the Amundsen and Bellingshausen Seas were not available to the weather forecasting centers. Results presented here indicate that a large amount of the available data is being incorporated and that large deficiencies identified in previous studies are being addressed, although areas of concern remain. Deficiencies in comparisons to specific stations are common to both analyses, implying continued communications problems. In particular, grid values corresponding to individual stations including the now-closed Leningradskaya base and Mirnyy are found to be conspicuously deficient at the 200 hPa level for both analyses. C1 NOAA, NWS, NCEP, CAMP SPRINGS, MD 20746 USA. RP Cullather, RI (reprint author), OHIO STATE UNIV, BYRD POLAR RES CTR, POLAR METEOROL GRP, COLUMBUS, OH 43210 USA. RI Grumbine, Robert/B-9865-2008; Bromwich, David/C-9225-2016 NR 43 TC 41 Z9 44 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1997 VL 102 IS D12 BP 13761 EP 13784 DI 10.1029/96JD03328 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH196 UT WOS:A1997XH19600033 ER PT J AU Donaldson, DJ Ravishankara, AR Hanson, DR AF Donaldson, DJ Ravishankara, AR Hanson, DR TI Detailed study of HOCl+HCl->Cl-2+H2O in sulfuric acid SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID EXCESS ACIDITY; HCL; CHLORINE; CLONO2; WATER; TEMPERATURE; KINETICS; ICE AB Reactive uptake coefficients for HOCl as a function of [HCl] were measured in a rotating wetted-wall flow reactor for several sulfuric acid solutions containing between 49 and 67 wt % H2SO4 at 220 and 250 K. The solubility of HOCl in sulfuric acid solutions at 220 and 250 K was also measured. Using these measured solubilities, calculated HCl solubilities, and estimated diffusivities for HOCl, the second-order rate coefficients (k(II)) in the liquid were extracted. At 250 K, k(II) increases with increasing acid concentration, from 3 x 10(5) M-1 s(-1) at 49 wt % acid to 5 x 10(6) M-1 s(-1) at 67 wt %. It is suggested that the reaction may involve an initial protonation of HOCl, followed by reaction of H2OCl+ with Cl-. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV TORONTO,DEPT CHEM,TORONTO,ON M5S 1A1,CANADA. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Donaldson, DJ (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Ravishankara, Akkihebbal/A-2914-2011; Donaldson, James/G-7120-2012 OI Donaldson, James/0000-0002-5090-3318 NR 53 TC 46 Z9 48 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 26 PY 1997 VL 101 IS 26 BP 4717 EP 4725 DI 10.1021/jp9633153 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XG935 UT WOS:A1997XG93500009 ER PT J AU Loeb, V Siegel, V HolmHansen, O Hewitt, R Fraser, W Trivelpiece, W Trivelpiece, S AF Loeb, V Siegel, V HolmHansen, O Hewitt, R Fraser, W Trivelpiece, W Trivelpiece, S TI Effects of sea-ice extent and krill or salp dominance on the Antarctic food web SO NATURE LA English DT Article ID EUPHAUSIA-SUPERBA; AUSTRAL SUMMER; VARIABILITY; PENINSULA; OCEAN AB Krill (Euphausia superba) provide a direct link between primary producers and higher trophic levels in the Antarctic marine food web(1-6). The pelagic tunicate Salpa thompsoni can also be important during spring and summer through the formation of extensive and dense blooms(6-9). Although salps are not a major dietary item for Antarctic vertebrate predators(7,10), their blooms can affect adult krill reproduction and survival of krill larvae. Here we provide data from 1995 and 1996 that support hypothesized relationships between krill, salps and region-wide sea-ice conditions(11,12). We have assessed salp consumption as a proportion of net primary production, and found correlations between herbivore densities and integrated chlorophyll-a that indicate that there is a degree of competition between krill and salps. Our analysis of the relationship between annual sea-ice cover and a longer time series of air temperature measurements(12,13) indicates a decreased frequency of winters with extensive sea-ice development over the last five decades. Our data suggest that decreased krill availability may affect the levels of their vertebrate predators. Regional warming and reduced krill abundance therefore affect the marine food web and krill resource management. C1 BUNDESFORSCH ANSTALT FISCHEREI,INST SEEFISCHEREI,D-22767 HAMBURG,GERMANY. UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093. NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,LA JOLLA,CA 92038. MONTANA STATE UNIV,DEPT BIOL,POLAR OCEANS RES GRP,BOZEMAN,MT 59717. RP Loeb, V (reprint author), MOSS LANDING MARINE LABS,POB 450,MOSS LANDING,CA 95039, USA. NR 29 TC 422 Z9 446 U1 19 U2 117 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD JUN 26 PY 1997 VL 387 IS 6636 BP 897 EP 900 DI 10.1038/43174 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XG416 UT WOS:A1997XG41600050 ER PT J AU Reipa, V Gaigalas, AK Vilker, VL AF Reipa, V Gaigalas, AK Vilker, VL TI Spectroscopic real-time ellipsometry of putidaredoxin adsorption on gold electrodes SO LANGMUIR LA English DT Article ID CYTOCHROME-C; REVERSIBLE ELECTROCHEMISTRY; BARE ELECTRODES; INTERFACE; FILMS AB Adsorption of putidaredoxin (Pdx) on gold electrodes was studied using dynamic spectroscopic ellipsometry and differential capacitance. A method to account for the metal surface optical perturbation during protein adsorption at constant potential is described. The method is based on the concept of the charged transition layer which develops between metal substrate and adsorbate. Transition-layer charge was determined from the differential capacitance and the ellipsometry measurements in buffer solutions. A three-phase (metal substrate/protein film/solution) reflecting surface model was amended with a charged metal transition layer as a fourth phase, which allowed the elucidation of the adsorbed Pdx complex index of refraction spectrum. On the basis of this spectrum, a time dependent protein surface concentration was calculated. For short times, this surface concentration was in good agreement with estimates based on mass transport limited adsorption. C1 UNIV CALIF LOS ANGELES,DEPT CHEM ENGN,LOS ANGELES,CA 90024. RP Reipa, V (reprint author), NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899, USA. NR 26 TC 15 Z9 15 U1 2 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUN 25 PY 1997 VL 13 IS 13 BP 3508 EP 3514 DI 10.1021/la9701541 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA XG715 UT WOS:A1997XG71500035 ER PT J AU Li, WM Cohen, RM Simons, DS Chi, PH AF Li, WM Cohen, RM Simons, DS Chi, PH TI Indium diffusion in n-type gallium arsenide SO APPLIED PHYSICS LETTERS LA English DT Article ID VAPOR-PHASE EPITAXY; GAAS; SUPERLATTICE; INTERDIFFUSION AB Diffusion of indium markers at T=900 degrees C have been measured in undoped and Te-doped GaAs epilayers grown by organometallic vapor phase epitaxy. The diffusivity was found to be a linear function of electron concentration over the range n=2x10(17)-1.5x10(19) cm(-3). The results are consistent with the interdiffusion of AlAs-GaAs superlattices, and the diffusivities of In and Al in GaAs at 900 degrees C are found to be essentially identical within experimental noise. The results strongly suggest that group III interdiffusion in GaAs is controlled by a Ga vacancy with a charge of -1. (C) 1997 American Institute of Physics. C1 NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. RP Li, WM (reprint author), UNIV UTAH,DEPT MAT SCI & ENGN,SALT LAKE CITY,UT 84112, USA. NR 16 TC 10 Z9 10 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 23 PY 1997 VL 70 IS 25 BP 3392 EP 3394 DI 10.1063/1.119181 PG 3 WC Physics, Applied SC Physics GA XH231 UT WOS:A1997XH23100022 ER PT J AU Zeissler, CJ AF Zeissler, CJ TI Comparison of semiconductor pixel array, phosphor plate, and track-etch detectors for alpha autoradiography SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 4th International Conference on Position-Sensitive Detectors CY SEP 09-13, 1996 CL MANCHESTER, ENGLAND AB The need to locate ''hot particles'' during environmental radioactivity characterization benefits from autoradiography. Three detectors are compared for the evaluation of point-source alpha emitters. (PuO2)-Pu-238 particles were used to compare a detector based on a pixel array, a phosphor imaging plate system, and a track-etch detector. The pixel-array detector is based on a charge injection device (CID) having nominally 14 mu m sized pixels in a 7 mm x 9 mm array. Processing at a 30 frames per second rate allows real-time display of results. Background interference is minimal even in long-duration exposures. The phosphor imaging plate system is subject to background accumulation. Track overlap makes single-event discrimination and quantification impractical, but a large exposure area and ease of use are distinct advantages. A system having a pixel size of 50 mu m was used. Track-etch detectors have the largest potential exposure area and best spatial resolution, the latter being limited by the amount of material etched, resolving power of the reading system, and the number of tracks recorded per source. Readout, however, can be time-consuming, and track overlap can make quantification difficult. The best spatial resolution, 10 mu m, was obtained with the track-etch detector, with a precision in location of 1 mu m. The phosphor plate system was capable of detecting 0.002 Bq sources in 2 d, whereas the track-etch and semiconductor pixel array were capable of detecting 0.0002 Bq sources in 2 d. The track-etch method was the most difficult, whereas the most rapid results were obtained with the real-time display of the semiconductor pixel array. RP Zeissler, CJ (reprint author), NATL INST STAND & TECHNOL,MAILSTOP 222-A113,GAITHERSBURG,MD 20899, USA. NR 3 TC 4 Z9 5 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 21 PY 1997 VL 392 IS 1-3 BP 249 EP 253 DI 10.1016/S0168-9002(97)00253-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XU981 UT WOS:A1997XU98100050 ER PT J AU Berkeland, DJ Cruz, FC Bergquist, JC AF Berkeland, DJ Cruz, FC Bergquist, JC TI Sum-frequency generation of continuous-wave light at 194 nm SO APPLIED OPTICS LA English DT Article DE sum-frequency generation; second-harmonic generation; ultraviolet light; lasers; diode lasers; optical cavities ID CAVITY AB Over 2 mW of continuous-wave tunable 194-nm light is produced by sum-frequency mixing approximately 500 mW of 792-nm and 500 mW of 257-nm radiation in beta-barium berate (BBO). The powers in both fundamental beams are enhanced in separate ring cavities whose optical paths overlap in the Brewster-cut BBO crystal. Due to the higher circulating fundamental powers, the sum-frequency-generated power is nearly 2 orders of magnitude greater than previously reported values. (C) 1997 Optical Society of America. RP Berkeland, DJ (reprint author), NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,325 BROADWAY,BOULDER,CO 80303, USA. RI Cruz, Flavio/A-6346-2012 OI Cruz, Flavio/0000-0003-3995-7910 NR 14 TC 34 Z9 34 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 1997 VL 36 IS 18 BP 4159 EP 4162 DI 10.1364/AO.36.004159 PG 4 WC Optics SC Optics GA XE301 UT WOS:A1997XE30100021 PM 18253443 ER PT J AU Shaw, JA Churnside, JH AF Shaw, JA Churnside, JH TI Scanning-laser glint measurements of sea-surface slope statistics SO APPLIED OPTICS LA English DT Article DE ocean optics; laser remote sensing; sea-surface roughness; atmospheric stability; statistical optics ID ROUGHENED WATER-SURFACE; OCEAN COLOR SENSORS; ATMOSPHERIC STABILITY; ROUGHNESS CONSIDERATIONS; LEAVING RADIANCE; BACKSCATTER; DEPENDENCE AB A scanning-laser glint meter designed for field measurements of sea-surface slope statistics is described. A narrow laser beam is scanned in a line, and specular reflections (glints) are counted in bins according to their slope angle. From normalized glint histograms, moments to the fourth order are calculated, and slope probability density functions are approximated with a Gram-Charlier expansion. Field measurements with this instrument show good agreement with previous results when the stability (essentially air-sea temperature difference) is near neutral (zero). Under conditions of negative stability (warm ocean), both the mean-square slope and the probability density function kurtosis increase. RP NOAA, ENVIRONM TECHNOL LAB, 325 BROADWAY, BOULDER, CO 80303 USA. RI Churnside, James/H-4873-2013 NR 39 TC 86 Z9 88 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 1997 VL 36 IS 18 BP 4202 EP 4213 DI 10.1364/AO.36.004202 PG 12 WC Optics SC Optics GA XE301 UT WOS:A1997XE30100026 PM 18253448 ER PT J AU Gilles, MK Turnipseed, AA Burkholder, JB Ravishankara, AR AF Gilles, MK Turnipseed, AA Burkholder, JB Ravishankara, AR TI A study of the Br+IO->I+BrO and the reverse reaction SO CHEMICAL PHYSICS LETTERS LA English DT Article ID REACTION CLO; IO; POTENTIALS; KINETICS; PRODUCT; CF3I AB The rate coefficient, k(1) (298 K)=(5.0+/-1.1)x10(-11) cm(3) molecule(-1) s(-1), for the reaction, Br+10-->I+BrO (1) was determined by monitoring the temporal profiles of IO in an excess of Br. The rate coefficient for the reverse reaction, I+BrO-->IO+Br(-1), k(-1) (298 K)=(1.9+/-1.1)x10(-11) cm(3) molecule(-1) s(-1), was determined by modeling IO temporal profiles, measured in the presence of BrO and O-3, in which the regeneration of IO was observed. From these rate coefficients, the difference in the heats of formations of IO and BrO, Delta(f)H(0) (298 K) (BrO)-Delta(f)H(0) (298 K) (IO), was calculated to be 0.5+/-0.6 kcal mol(-1). (C) 1997 Elsevier Science B.V. C1 NOAA,AERON LAB,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 26 TC 24 Z9 24 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 20 PY 1997 VL 272 IS 1-2 BP 75 EP 82 DI 10.1016/S0009-2614(97)00485-5 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XH266 UT WOS:A1997XH26600013 ER PT J AU Drews, AR WongNg, W Vanderah, TA Roth, RS AF Drews, AR WongNg, W Vanderah, TA Roth, RS TI Preparation and crystal structure of Sr6TiNb4O18 SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE Sr6TiNb4O18; strontium titanium niobium oxide; single-crystal structure determination; microwave dielectric ceramics; crystal growth; X-ray ID SOLIDS AB The crystal structure of newly prepared Sr6TiNb4O18 was determined by single-crystal X-ray diffraction and is described here. This compound crystallizes in space group R3m (No. 160; a = 5.6437(5), c = 41.347(3) Angstrom; Z = 3). The structure consists of infinite perovskite-type slabs, five octahedra in thickness, extending parallel to (111)(perovskite). All Sr ions are 12-coordinated; Nb5+ and Ti4+ are distributed among the octahedral M sites. The cation coordination spheres in and bordering the gaps between the perovskite type slabs are highly distorted with bond valence sums indicative of residual chemical strain: Sr-O bonds are stretched, M-O bonds compressed. Nb5+ preferentially occupies the distorted octahedral sites that border the gaps; the least amount of the higher valent metal is found in octahedral sites embedded in the center of the slabs. Similar crystal-chemical effects were reported for isostructural Ba6TiNb4O18 and for Sr5TiNb4O17, also a perovskite-slab-type structure but with slices cut parallel to (110)(perovskite). C1 NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899. NR 15 TC 15 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD JUN 20 PY 1997 VL 255 IS 1-2 BP 243 EP 247 DI 10.1016/S0925-8388(96)02865-4 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA XJ449 UT WOS:A1997XJ44900039 ER PT J AU Roehl, CM Burkholder, JB Moortgat, GK Ravishankara, AR Crutzen, PJ AF Roehl, CM Burkholder, JB Moortgat, GK Ravishankara, AR Crutzen, PJ TI Temperature dependence of UV absorption cross sections and atmospheric implications of several alkyl iodides SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ULTRAVIOLET-ABSORPTION; METHYL-IODIDE; OZONE DEPLETION; AIR; SPECTRUM; KINETICS; PHOTOCHEMISTRY; RADICALS; METHANES; PHASE AB The ultraviolet absorption spectra of a number of alkyl iodides which have been found in the troposphere, CH3I, C2H5I, CH3CH2CH2I, CH3CHICH3, CH2I2, and CH2ClI, have been measured over the wavelength range 200-380 nm and at temperatures between 298 and 210 K. The absorption spectra of the monoiodides CH3I, C2H5I, CH3CH2CH2I, and CH3CHICH3 are nearly identical in shape and magnitude and consist of single broad bands centered near 260 nn. The addition of a chlorine atom in CH2ClI shifts its spectrum to longer wavelengths (sigma(max) at 270 nm). The spectrum of CH2I2 is further red-shifted, reaching a maximum of 3.85 x 10(-18) cm(2) molecule(-1) at 288 nm and exhibiting strong absorption in the solar actinic region, lambda>290 nm. Atmospheric photolysis rate constants, J values, have been calculated assuming quantum efficiencies of unity for different solar zenith angles as a function of altitude using the newly measured cross sections. Surface photolysis rate constants. calculated from the absorption cross sections measured at 298 K, range from 3 x 10(-6)s(-1) for CH3I to 5 x 10(-3)s(-1) for CH2I2 at a solar zenith angle of 40 degrees. C1 NOAA, AERON LAB, BOULDER, CO 80303 USA. MAX PLANCK INST CHEM, DIV ATMOSPHER CHEM, D-55020 MAINZ, GERMANY. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. UNIV COLORADO, DEPT CHEM & BIOCHEM, BOULDER, CO 80309 USA. RI Crutzen, Paul/F-6044-2012; Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 39 TC 73 Z9 73 U1 0 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 12819 EP 12829 DI 10.1029/97JD00530 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900004 ER PT J AU Waugh, DW Plumb, RA Elkins, JW Fahey, DW Boering, KA Dutton, GS Volk, CM Keim, E Gao, RS Daube, BC Wofsy, SC Loewenstein, M Podolske, JR Chan, KR Proffitt, MH Kelly, K Newman, PA Lait, LR AF Waugh, DW Plumb, RA Elkins, JW Fahey, DW Boering, KA Dutton, GS Volk, CM Keim, E Gao, RS Daube, BC Wofsy, SC Loewenstein, M Podolske, JR Chan, KR Proffitt, MH Kelly, K Newman, PA Lait, LR TI Mixing of polar vortex air into middle latitudes as revealed by tracer-tracer scatterplots SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTARCTIC OZONE HOLE; LOWER STRATOSPHERE; WINTER; TRANSPORT; N2O; DENITRIFICATION; CO2; DEHYDRATION; DYNAMICS; AIRCRAFT AB The occurrence of mixing of polar vortex air with midlatitude air is investigated by examining the scatterplots of insitu measurements of long-lived tracers from the NASA ER-2 aircraft during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE, April, May 1993; northern hemisphere) and the Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/MAESA, March-October 1994; southern hemisphere) campaigns. The tracer-tracer scatterplots from SPADE form correlation curves which differ from those measured during previous aircraft campaigns (Airborne Antarctic Ozone Experiment (AAOE), Airborne Arctic Stratospheric Experiments I (AASE I) and II (AASE II)). It is argued that these anomalous linear correlation curves are ''mixing lines'' resulting from the recent mixing of polar vortex air into the middle latitude environment. Further support for this mixing scenario is provided by contour advection calculations and calculations with a simple one-dimensional strain-diffusion model. The scatterplots from the midwinter deployments of ASHOE/MAESA are consistent with those from previous midwinter measurements (i.e., no mixing lines), but the spring CO2:N2O scatterplots form altitude-dependent mixing lines which indicate that air from the vortex edge region (but not from the inner vortex) is mixing with midlatitude air during this period. These results suggest that at altitudes above about 16 km the mixing of polar vortex air into middle latitudes varies with season: in northern and southern midwinter this mixing rarely occurs, in southern spring mixing of vortex-edge air occurs, and after the vortex breakup mixing of inner vortex air occurs. C1 HARVARD UNIV, DEPT EARTH & PLANETARY SCI, CAMBRIDGE, MA 02138 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80303 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. MIT, DEPT EARTH ATMOSPHER & PLANETARY SCI, CAMBRIDGE, MA 02139 USA. RP Waugh, DW (reprint author), MONASH UNIV, COOPERAT RES CTR SO HEMISPHERE METEOROL, WELLINGTON RD, CLAYTON, VIC 3168, AUSTRALIA. RI Newman, Paul/D-6208-2012; Gao, Ru-Shan/H-7455-2013; Fahey, David/G-4499-2013; Waugh, Darryn/K-3688-2016 OI Newman, Paul/0000-0003-1139-2508; Fahey, David/0000-0003-1720-0634; Waugh, Darryn/0000-0001-7692-2798 NR 51 TC 127 Z9 129 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13119 EP 13134 DI 10.1029/96JD03715 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900028 ER PT J AU Grose, WL Lingenfelser, GS Russell, JM Pierce, RB Fairlie, TD Proffitt, MH AF Grose, WL Lingenfelser, GS Russell, JM Pierce, RB Fairlie, TD Proffitt, MH TI Intercomparison of ozone measurements in the lower stratosphere from the UARS halogen occultation experiment and the ER-2 UV absorption photometer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB Ozone data obtained by the Halogen Occultation Experiment (HALOE) on the NASA Upper Atmosphere Research Satellite (UARS) have been compared with ozone data obtained by the NOAA dual-beam, UV absorption photometer on the NASA ER-2 aircraft during the 1994 Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/MAESA) campaign. This paper describes the measurement characteristics of the two instruments and the precision and accuracy of the two data sets. A total of 26 cases are discussed in which the two different measurements occur within 24 hours, 2.5 degrees latitude, and 10 degrees longitude of each other. Generally, agreement between the two data sets improved the closer in time and space the two measurements occurred. The agreement was better than 10% at ER-2 cruise altitudes (similar to 50-70 mbar) where the error estimated for HALOE is slightly larger than 18%. C1 NASA, LANGLEY RES CTR, SCI APPLICAT INT CORP, HAMPTON, VA 23681 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. HAMPTON UNIV, DEPT PHYS, HAMPTON, VA 23668 USA. RP Grose, WL (reprint author), NASA, LANGLEY RES CTR, SCI & TECHNOL CORP, MS 401B, HAMPTON, VA 23681 USA. RI Pierce, Robert Bradley/F-5609-2010 OI Pierce, Robert Bradley/0000-0002-2767-1643 NR 7 TC 2 Z9 2 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13135 EP 13140 DI 10.1029/96JD03060 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900029 ER PT J AU Nevison, CD Solomon, S Garcia, RR Fahey, DW Keim, ER Loewenstein, M Podolske, JR Gao, RS Wamsley, RC Donnelly, SG DelNegro, LA AF Nevison, CD Solomon, S Garcia, RR Fahey, DW Keim, ER Loewenstein, M Podolske, JR Gao, RS Wamsley, RC Donnelly, SG DelNegro, LA TI Influence of Antarctic denitrification on two-dimensional model NOy/N2O correlations in the lower stratosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WINTER POLAR STRATOSPHERES; CHEMICAL-COMPOSITION; MIDDLE ATMOSPHERE; OZONE EXPERIMENT; HNO3; BREAKING; DYNAMICS; CLONO2; N2O AB The mechanisms responsible for latitudinal and seasonal variations in the stratospheric No-y/N2O correlation, represented by the effective NOy yield from N2O loss, or F-NOy, are explored using the Garcia-Solomon two-dimensional model. The model is run with and without Antarctic denitrification. Model results are compared to in situ NOy/N2O measurements taken onboard the NASA ER-2 high-altitude aircraft in the lower stratosphere during the 1994 Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft campaign, and to global-scale measurements taken onboard the Upper Atmosphere Research Satellite (UARS) from 1992 to 1993. The southern hemisphere midlatitude seasonal cycle observed by the ER-2 and the latitudinal gradients observed by UARS are consistent with the results of the denitrified model, although some aspects of the model results are sensitive to prescribed and/or calculated horizontal diffusion coefficients. The consistency with observations supports the model's prediction of a seasonal cycle in which F-NOy increases at southern midlatitudes during winter due to descent of F-NOy -enriched air from above and decreases in spring due to mixing with F-NOy -depleted air from the denitrified polar vortex. Antarctic denitrification appears to affect midlatitudes mainly by a one-time dilution of the polar vortex following the final warming rather than by flow-through vortex processing during the winter. Because of the high concentrations of NOy at polar latitudes before denitrification a can be removed by a one-time dilution of the large fraction of total stratospheric NOy denitrified polar vortex. The nondenitrified model results generally do not agree well with observations, suggesting that denitrification strongly influences latitudinal and seasonal variations in F-NOy in the southern hemisphere. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO USA. UNIV COLORADO, DEPT BIOL & CHEM, BOULDER, CO 80309 USA. RP Nevison, CD (reprint author), NOAA, ERL, R-E-AL8, 325 BROADWAY, BOULDER, CO 80303 USA. RI Gao, Ru-Shan/H-7455-2013; Fahey, David/G-4499-2013 OI Fahey, David/0000-0003-1720-0634 NR 30 TC 11 Z9 11 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13183 EP 13192 DI 10.1029/96JD03250 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900033 ER PT J AU Keim, ER Loewenstein, M Podolske, JR Fahey, DW Gao, RS Woodbridge, EL Wamsley, RC Donnelly, SG DelNegro, LA Nevison, CD Solomon, S Rosenlof, KH Scott, CJ Ko, MKW Weisenstein, D Chan, KR AF Keim, ER Loewenstein, M Podolske, JR Fahey, DW Gao, RS Woodbridge, EL Wamsley, RC Donnelly, SG DelNegro, LA Nevison, CD Solomon, S Rosenlof, KH Scott, CJ Ko, MKW Weisenstein, D Chan, KR TI Measurements of the NOy - N2O correlation in the lower stratosphere: Latitudinal and seasonal changes and model comparisons SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TOTAL REACTIVE NITROGEN; ANTARCTIC OZONE HOLE; WINTER POLAR STRATOSPHERES; AIRCRAFT MEASUREMENTS; ARCTIC STRATOSPHERE; MIDDLE ATMOSPHERE; ODD NITROGEN; NITRIC-ACID; AASE-II; VORTEX AB The tracer species nitrous oxide, N2O, and the reactive nitrogen reservoir, NOy, were measured in situ using instrumentation carried aboard the NASA ER-2 high altitude aircraft as part of the NASA Airborne Southern Hemisphere Ozone Expedition/Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/MAESA) and Stratospheric Tracers of Atmospheric Transport (STRAT) missions. Measurements were made throughout the latitude range of 70 degrees S to 60 degrees N over the time period of March to October 1994 and October 1995 to January 1996, which includes the period when the Antarctic polar vortex is most intense. The correlation plots of NOy with N2O reveal compact, near-linear curves throughout data obtained in the lower stratosphere (50 mbar to 200 mbar). The average slope of the correlation, Delta NOy/Delta N2O, in the southern hemisphere (SH) exhibited a much larger seasonal variation during this time period than was observed in the northern hemisphere (NH). Between March and October in the potential temperature range of 400 K to 525 K, the correlation slope in the SH midlatitudes increased by 28%. A smaller but still positive increase in the correlation slope was observed for higher-latitude data obtained within or near the edge of the SH polar vortex. At NH midlatitudes the correlation slope did not significantly change between March and October, while between October and January the slope increased by +7%. The larger SH midlatitude increase is consistent with ongoing descent throughout the winter and spring and also suggests that denitrification, the irreversible loss of HNO3 through sedimentation of cloud particles, is not a significant term (<10-15%) in the budget of NOy at SH midlatitudes during the wintertime, A secular increase in the correlation slope is ruled out by comparison with SH data obtained during the 1987 Airborne Antarctic Ozone Expedition (AAOE) aircraft campaign. These results suggest that a seasonal cycle exists in the correlation slope for both hemispheres, with the SH correlation slope returning to the April value during the SH spring and summer. Changes in stratospheric circulation also probably play a role in both the SH and the NH correlation slope seasonal cycles. Comparisons with two-dimensional model results suggest that the slope decreases when the denitrified Antarctic vortex is diluted into midlatitudes upon vortex breakup in the spring and that through the descent of stratospheric air, the slope recovers during the following fall/winter period. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. UNIV COLORADO, DEPT BIOL & CHEM, BOULDER, CO 80309 USA. ATMOSPHER & ENVIRONM RES INC, CAMBRIDGE, MA 02139 USA. RP Keim, ER (reprint author), NOAA, AERON LAB, 325 BROADWAY, BLDG 24, BOULDER, CO 80303 USA. RI Gao, Ru-Shan/H-7455-2013; Rosenlof, Karen/B-5652-2008; Ko, Malcolm/D-5898-2015; Fahey, David/G-4499-2013 OI Rosenlof, Karen/0000-0002-0903-8270; Fahey, David/0000-0003-1720-0634 NR 50 TC 36 Z9 36 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13193 EP 13212 DI 10.1029/96JD03921 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900034 ER PT J AU Rosenlof, KH Tuck, AF Kelly, KK Russell, JM McCormick, MP AF Rosenlof, KH Tuck, AF Kelly, KK Russell, JM McCormick, MP TI Hemispheric asymmetries in water vapor and inferences about transport in the lower stratosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTARCTIC VORTEX; ANNUAL CYCLE; LATE WINTER; OZONE LOSS; HALOE; DEHYDRATION; EVOLUTION; AIR; VARIABILITY; DYNAMICS AB Both satellite water vapor measurements and in situ aircraft measurements indicate that the southern hemisphere lower stratosphere is drier than that of the northern hemisphere in an annual average sense. This is the result of a combination of factors. At latitudes poleward of similar to 50 degrees S, dehydration in the Antarctic polar vortex lowers water vapor mixing ratios relative to those in the north during late winter and spring. Equatorward of similar to 50 degrees S, water vapor in the lower stratosphere is largely controlled by the tropical seasonal cycle in water vapor coupled with the seasonal cycle in extratropical descent. During the tropical moist period (June, July, and August), air ascending in the Indian monsoon region influences the northern hemisphere more than the southern hemisphere, resulting in a moister northern hemisphere lower stratosphere. This tropical influence is confined to levels beneath 60 mbar at low latitudes, and beneath 90 mbar at high latitudes. During the tropical dry period (December, January, and February), dry air spreads initially into both hemispheres. However, the stronger northern hemisphere wintertime descent that exists relative to that of southern hemisphere summer transports the dry air out of the northern hemisphere lower stratosphere more quickly than in the south. This same hemispheric asymmetry in winter descent (greater descent rates during northern hemisphere winter than during southern hemisphere winter) brings down a greater quantity of ''older'' higher water vapor content air in the north, which also acts to moisten the northern hemisphere lower stratosphere relative to the southern hemisphere. These factors all act together to produce a drier southern hemisphere lower stratosphere as compared to that in the north. The overall picture that comes from this study in regards to transport characteristics is that the stratosphere can be divided into three regions. These are (1) the ''overworld'' where mass transport is controlled by nonlocal dynamical processes, (2) the ''tropically controlled transition region'' made up of relatively young air that has passed through (and been dehydrated by) the cold tropical tropopause, and (3) the stratospheric part of the ''middleworld'' or ''lowermost stratosphere'', where troposphere-stratosphere exchange can occur adiabatically. Satellite water vapor measurements indicate that the base of the ''overworld'' is near 60 mbar in the tropics, or near the 450 K isentropic surface. C1 COOPERAT INST RES ENVIRONM SCI, BOULDER, CO USA. HAMPTON UNIV, DEPT PHYS, HAMPTON, VA 23668 USA. RP Rosenlof, KH (reprint author), NOAA, AERON LAB, 325 BROADWAY, BOULDER, CO 80303 USA. RI Tuck, Adrian/F-6024-2011; Rosenlof, Karen/B-5652-2008 OI Tuck, Adrian/0000-0002-2074-0538; Rosenlof, Karen/0000-0002-0903-8270 NR 40 TC 155 Z9 155 U1 2 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13213 EP 13234 DI 10.1029/97JD00873 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900035 ER PT J AU Jaegle, L Webster, CR May, RD Scott, DC Stimpfle, RM Kohn, DW Wennberg, PO Hanisco, TF Cohen, RC Proffitt, MH Kelly, KK Elkins, J Baumgardner, D Dye, JE Wilson, JC Pueschel, RF Chan, KR Salawitch, RJ Tuck, AF Hovde, SJ Yung, YL AF Jaegle, L Webster, CR May, RD Scott, DC Stimpfle, RM Kohn, DW Wennberg, PO Hanisco, TF Cohen, RC Proffitt, MH Kelly, KK Elkins, J Baumgardner, D Dye, JE Wilson, JC Pueschel, RF Chan, KR Salawitch, RJ Tuck, AF Hovde, SJ Yung, YL TI Evolution and stoichiometry of heterogeneous processing in the Antarctic stratosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID NITRIC-ACID TRIHYDRATE; WINTER POLAR STRATOSPHERES; ABSORPTION CROSS-SECTIONS; LIMB EMISSION-SPECTRA; OZONE DEPLETION; ER-2 AIRCRAFT; INSITU MEASUREMENTS; REACTIVE NITROGEN; HYDROGEN-CHLORIDE; SULFATE AEROSOLS AB Simultaneous in situ measurements of HCl and ClO have been made for the first time in the southern hemisphere, allowing a systematic study of the processes governing chlorine activation between 15 and 20 km in the 1994 Antarctic winter. Data for several other gases (O-3, NO, NOy, OH, HO2, N2O, CH4, CO, H2O, CFCs), particulates, and meteorological parameters were collected from the ER-2 aircraft out of New Zealand as part of the 1994 Airborne Southern Hemisphere Ozone Experiment/Measurements of Atmospheric Effects of Stratospheric Ail cl att (ASHOE/MAESA) campaign. Observations from the ER-2 in the fall (April-May), prior to polar night, show that chlorine activation begins with 60-75% of inorganic chlorine as HCl. By midwinter (July-August), near-total removal of HCl is observed. The wintertime loss of HCl in air recently exposed to extreme temperatures is found to be correlated with high levels of reactive chlorine (ClO and its dimer, Cl2O2) in the linear fashion expected from the stoichiometry of the heterogeneous reaction of hydrochloric acid with chlorine nitrate on polar stratospheric ic clouds (PSCs): HCl + ClONO2 --> Cl-2 + HNO3. To constrain the role of different heterogeneous reactions and PSC types, we have used a photochemical trajectory model which includes heterogeneous sulfate and PSC chemistry. Model calculations of the evolution of reactive gases ale compared with the in situ observations. In addition, simultaneous measurements of OH and HO2 are used as a diagnostic for the occurrence of the heterogeneous reaction HOCl + HCl --> Cl-2 + H2O, which contributes to suppressed levels of HOx inside the vortex. It is shown that the amount of chlorine activation is not strongly dependent on the composition of PSCs. However, HOx levels exhibit different signatures depending on the type of heterogeneous surfaces that affected chlorine activation. Furthermore, this analysis implies that in the edge legion of the Antarctic vortex, the observed near-total removal of HCl can result from latitudinal excursions of air parcels in and out of sunlight during the winter, which photochemically resupply HOCl and ClONO2 as oxidation partners for HCl. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. HARVARD UNIV, DEPT CHEM, CAMBRIDGE, MA 02138 USA. NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. CALTECH, JET PROP LAB, DIV ATMOSPHER CHEM, PASADENA, CA 91109 USA. UNIV DENVER, DEPT ENGN, DENVER, CO 80208 USA. CALTECH, DIV GEOL & PLANETARY SCI, PASADENA, CA 91125 USA. RI Salawitch, Ross/B-4605-2009; Cohen, Ronald/A-8842-2011; Tuck, Adrian/F-6024-2011; Wennberg, Paul/A-5460-2012 OI Salawitch, Ross/0000-0001-8597-5832; Cohen, Ronald/0000-0001-6617-7691; Tuck, Adrian/0000-0002-2074-0538; NR 104 TC 17 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13235 EP 13253 DI 10.1029/97JD00935 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900036 ER PT J AU DelNegro, LA Fahey, DW Donnelly, SG Gao, RS Keim, ER Wamsley, RC Woodbridge, EL Dye, JE Baumgardner, D Gandrud, BW Wilson, JC Jonsson, HH Loewenstein, M Podolske, JR Webster, CR May, RD Worsnop, DR Tabazadeh, A Tolbert, MA Kelly, KK Chan, KR AF DelNegro, LA Fahey, DW Donnelly, SG Gao, RS Keim, ER Wamsley, RC Woodbridge, EL Dye, JE Baumgardner, D Gandrud, BW Wilson, JC Jonsson, HH Loewenstein, M Podolske, JR Webster, CR May, RD Worsnop, DR Tabazadeh, A Tolbert, MA Kelly, KK Chan, KR TI Evaluating the role of NAT, NAD, and liquid H2SO4/H2O/HNO3 solutions in Antarctic polar stratospheric cloud aerosol: Observations and implications SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NITRIC-ACID TRIHYDRATE; AIRBORNE LIDAR OBSERVATIONS; TOTAL REACTIVE NITROGEN; SULFURIC-ACID; TEMPERATURE-FLUCTUATIONS; ARCTIC STRATOSPHERE; REFRACTIVE-INDEXES; SULFATE AEROSOLS; OZONE EXPERIMENT; HYDROGEN-BOND AB Airborne measurements of total reactive nitrogen (NOy) and polar stratospheric cloud (PSC) aerosol particles were made in the Antarctic (68 degrees S) as part of the NASA Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/MAESA) campaign in late July 1994. As found in both polar regions during previous studies, substantial PSC aerosol volume containing NOy was observed al temperatures above the frost point, confirming the presence of particles other than water ice. The composition of the aerosol particles is evaluated using equilibrium expressions for nitric acid trihydrate (NAT), nitric acid dihydrate (NAD), and the supercooled ternary solution (STS) composed of nitric acid (HNO3), sulfuric acid (H2SO4), and water (H2O). The equilibrium abundance of condensed HNO3 is calculated for each phase and compared to estimates made using observations of aerosol volume and NOy. The best agreement is found for STS composition, using criteria related to the onset and abundance of aerosol volume along the flight track. Throughout the PSC region, a comparison of the number of particles between 0.4 and 4.0 mu m diameter with the number of available nuclei indicates that a significant fraction of the background aerosol number participates in PSC growth. Modeled STS size distributions at temperatures below 191 K compare favorably with measured size distributions of PSC aerosol. Calculations of the heterogeneous loss of chlorine nitrate (ClONO2) show that the reactivity of the observed PSC surface area is 30 to 300% greater with STS than with NAT composition for temperatures less than 195 K. The total volume of STS PSCs is shown to be more sensitive than NAT to increases in H2O, HNO3, and H2SO4 from supersonic aircraft fleet emissions. Using the current observations and perturbations predicted by the current aircraft assessments, an increase of 50 to 260% in STS aerosol volume is expected at the lowest observed temperatures (190 to 192 K), along with an extension of significant PSC activity to regions similar to 0.7 K higher in temperature. These results improve our understanding of PSC aerosol formation in polar regions while strengthening the requirement to include STS aerosols in studies of polar ozone loss and the effects of aircraft emissions. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. UNIV COLORADO, DEPT CHEM & BIOCHEM, BOULDER, CO 80309 USA. UNIV DENVER, DEPT ENGN, DENVER, CO 80208 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, LA JOLLA, CA 92093 USA. AERODYNE RES INC, BILLERICA, MA 02139 USA. RP DelNegro, LA (reprint author), NOAA, AERON LAB, R-E-AL6, 325 BROADWAY, BOULDER, CO 80303 USA. RI Worsnop, Douglas/D-2817-2009; Gao, Ru-Shan/H-7455-2013; Fahey, David/G-4499-2013 OI Worsnop, Douglas/0000-0002-8928-8017; Fahey, David/0000-0003-1720-0634 NR 80 TC 44 Z9 44 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13255 EP 13282 DI 10.1029/97JD00764 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900037 ER PT J AU McGee, TJ Gross, M Singh, U Kimvilakani, P Matthews, A Bodeker, G Conner, B Tsou, JJ Proffitt, M Margitan, J AF McGee, TJ Gross, M Singh, U Kimvilakani, P Matthews, A Bodeker, G Conner, B Tsou, JJ Proffitt, M Margitan, J TI Vertical profile measurements of ozone at Lauder, New Zealand during ASHOE/MAESA SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERIC OZONE; LIDAR AB The Goddard Space Flight Center stratospheric ozone lidar was deployed at the National Institute for Water and Atmospheric Research (NIWA) facility at Lauder, New Zealand (45 degrees S, 169 degrees E), during all four of the Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/ MAESA) flight periods. The site is about 500 km south of Christchurch. Efforts were made to acquire lidar data before dawn and after sunset on the days the ER-2 was flown. A total of 79 measurements were made on 47 individual nights. Each measurement provided vertical profiles of aerosols, temperature, and ozone. Profiles begin at similar to 8 km and extend to 35, 50-55, and 75 km for aerosols, ozone, and temperature, respectively. NIWA personnel launched electrochemical concentration cell ozonesondes on a number of these occasions. A summary of these data will be presented along with comparisons with data from ER-2 instruments. Average profiles for each of the four ASHOE/MAESA deployments were constructed for use as a climatological profile for model initialization. C1 NATL INST WATER & ATMOSPHER RES, LAUDER, NEW ZEALAND. HUGHES STX CORP, LANHAM, MD 20706 USA. IDEA CORP, BELTSVILLE, MD 20705 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. LOCKHEED ENGN & SCI CO, HAMPTON, VA 23665 USA. RP McGee, TJ (reprint author), NASA, GODDARD SPACE FLIGHT CTR, MC 916, GREENBELT, MD 20771 USA. RI Bodeker, Greg/A-8870-2008; McGee, Thomas/G-4951-2013 OI Bodeker, Greg/0000-0003-1094-5852; NR 8 TC 3 Z9 3 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13283 EP 13289 DI 10.1029/96JD03062 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900038 ER PT J AU Folkins, I Chatfield, R Baumgardner, D Proffitt, M AF Folkins, I Chatfield, R Baumgardner, D Proffitt, M TI Biomass burning and deep convection in southeastern Asia: Results from ASHOE/MAESA SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID POLAR STRATOSPHERIC CLOUD; TROPOSPHERIC OZONE; CARBON-MONOXIDE; ATMOSPHERIC CHEMISTRY; EQUATORIAL PACIFIC; RADIATIVE-TRANSFER; BOUNDARY-LAYER; NITRIC-OXIDE; WATER-VAPOR; TRANSPORT AB There was extensive biomass burning in Indonesia, northern Australia, and New Guinea during September and October 1994. This paper discusses two accidental encounters of biomass plumes from the 1994 Airborne Southern Hemisphere Ozone Experiment and Measurements for Assessing the Effects of Stratospheric Aircraft campaign (ASHOE/MAESA). During the October 23 descent into Fiji, and an ascent from Fiji on October 24, the NASA ER-2 passed through layers highly enhanced in NO, NOy, CO, and O-3. These layers occurred near an altitude of 15 km. Back trajectories and satellite images indicate that the layers probably originated as outflow from a convective disturbance near New Guinea. The measurements indicate that deep convection can inject emissions from southeast Asian biomass burning to near tropical tropopause altitudes. Deep convection magnifies the impact of biomass burning on tropospheric chemistry because of the much longer residence times and chemical lifetimes of species in the upper tropical troposphere. Transport of the products of southeast Asian biomass burning into the upper tropical troposphere, followed by southward high-level outflow and advection by the subtropical jet, may play a significant role in dispersing these emissions on a global scale. Anthropogenic emissions from countries in southeast Asia are likely to increase in the future as these countries become more highly industrialized. This transport mechanism may play a role in increasing the impact of these types of emissions as well. C1 NASA, AMES RES CTR, EARTH SYST SCI DIV, MOFFETT FIELD, CA 94035 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. DALHOUSIE UNIV, ATMOSPHER SCI PROGRAM, DEPT PHYS, HALIFAX, NS B3H 4J1, CANADA. NATL CTR ATMOSPHER RES, DIV ATMOSPHER CHEM, RAF, BOULDER, CO 80307 USA. COOPERAT INST RES ENVIRONM SCI, BOULDER, CO USA. RP Folkins, I (reprint author), DALHOUSIE UNIV, DEPT OCEANOG, HALIFAX, NS B3H 4J1, CANADA. NR 50 TC 66 Z9 65 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1997 VL 102 IS 11D BP 13291 EP 13299 DI 10.1029/96JD03711 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XG179 UT WOS:A1997XG17900039 ER PT J AU Hanson, DR AF Hanson, DR TI Surface-specific reactions on liquids SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID CHEMICAL-REACTION; AQUEOUS SURFACES; INTERFACE AB Surface-specific reactivity is included in the theory of gas-liquid reactions. An expression for the reaction probability (fractional loss of a gas-phase species on collision with a liquid surface) is derived and compared to equations derived previously. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Hanson, DR (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 10 TC 84 Z9 84 U1 0 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JUN 19 PY 1997 VL 101 IS 25 BP 4998 EP 5001 DI 10.1021/jp970461f PG 4 WC Chemistry, Physical SC Chemistry GA XF418 UT WOS:A1997XF41800021 ER PT J AU Onda, M Bitoh, Y Walker, ARH AF Onda, M Bitoh, Y Walker, ARH TI The microwave spectrum and structure of the 1,2,3-trifluorobenzene center dot center dot center dot argon complex SO JOURNAL OF MOLECULAR STRUCTURE LA English DT Article; Proceedings Paper CT XXIIIrd European Congress on Molecular Spectroscopy CY AUG 25-30, 1996 CL BALATONFURED, HUNGARY DE microwave spectroscopy; 1,2,3-trifluorobenzene center dot center dot center dot argon complex; van der Waals complexes AB The microwave spectrum of the 1,2,3-trifluorobenzene...argon complex has been studied with a pulsed-beam Fourier-transform Fabry-Perot-cavity spectrometer (MB-FTMW). The rotational and centrifugal distortion constants of normal and 1(3)-C-13-species of the complex were obtained as follows: A = 1023.9040(1)MHz, B = 831.0917(1)MHz, C = 734.9059(1) MHz, Delta(J) = 1.1384(9) kHz, Delta(JK) = 4.3828(30)kHz, Delta(K) = -4.9329(28) kHz, delta(J) = 0.0081(3) kHz, delta(K) = 1.3756(21) kHz for normal species and A = 1020.921(3) MHz, B = 830.223(2) MHz, C = 732.766(7) MHz for 1-C-13- species. The structure of the complex determined has C-s symmetry and the argon atom is located almost centrally above the benzene ring. (C) 1997 Elsevier Science B.V. C1 NIST,DIV MOL PHYS,GAITHERSBURG,MD 20899. RP Onda, M (reprint author), SOPHIA UNIV,DEPT CHEM,CHIYODA KU,7-1 KIOICHO,TOKYO 102,JAPAN. RI Hight Walker, Angela/C-3373-2009 OI Hight Walker, Angela/0000-0003-1385-0672 NR 6 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2860 J9 J MOL STRUCT JI J. Mol. Struct. PD JUN 16 PY 1997 VL 410 BP 51 EP 54 DI 10.1016/S0022-2860(96)09564-6 PG 4 WC Chemistry, Physical SC Chemistry GA XL065 UT WOS:A1997XL06500013 ER PT J AU Ali, MA Kim, YK Hwang, W Weinberger, NM Rudd, ME AF Ali, MA Kim, YK Hwang, W Weinberger, NM Rudd, ME TI Electron-impact total ionization cross sections of silicon and germanium hydrides SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SILANE; DEPOSITION; SI2H6; SIH4 AB Electron-impact total ionization cross sections of some silicon and germanium compounds have been calculated by applying a new theoretical model that has been found to be reliable for a wide range of molecules. The new theory, the binary-encounter-Bethe (BEB) model, combines the binary-encounter theory and the Bethe theory for electron-impact ionization, and uses simple theoretical molecular orbital data-binding energies, average kinetic energies, and occupation numbers-which are readily available from molecular structure codes. Total ionization cross sections of SiH, SiH2, SiH3, SiH4, Si2H6, Si(CH3)(4), GeH, GeH2, GeH4, GeH4, and Ge2H6 are presented for incident electron energies T from threshold to 1 keV, and compared to available experimental data. Theory and experiment agree well for SiHx, x=1-4, from thresholds to T <80 eV, while theoretical peaks occur at lower T than experimental peaks for SiHx, x=1-3. No experimental data are available for germanium hydrides for comparison. The theoretical cross sections are given by a compact analytic form suitable for applications in plasma processing. (C) 1997 American Institute of Physics. C1 NIST,GAITHERSBURG,MD 20899. UNIV NEBRASKA,DEPT PHYS & ASTRON,LINCOLN,NE 68588. RP Ali, MA (reprint author), HOWARD UNIV,DEPT CHEM,WASHINGTON,DC 20059, USA. NR 22 TC 74 Z9 74 U1 3 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1997 VL 106 IS 23 BP 9602 EP 9608 DI 10.1063/1.473842 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XE026 UT WOS:A1997XE02600021 ER PT J AU Hartling, RC Pereira, JJ Kunkel, JG AF Hartling, RC Pereira, JJ Kunkel, JG TI Characterization of a heat-stable fraction of lipovitellin and development of an immunoassay for vitellogenin and yolk protein in winter flounder (Pleuronectes americanus) SO JOURNAL OF EXPERIMENTAL ZOOLOGY LA English DT Article ID LONG-ISLAND-SOUND; LINKED-IMMUNOSORBENT-ASSAY; RAINBOW-TROUT; SALMO-GAIRDNERI; PSEUDOPLEURONECTES-AMERICANUS; OOCYTE MATURATION; OVARIAN UPTAKE; FUNDULUS OOCYTES; INVITRO; SEQUESTRATION AB An enzyme-linked immunoabsorbent assay was developed for detection and quantification of the yolk protein lipovitellin (Lv) and its plasma precursor, vitellogenin (Vg), in winter flounder (Pleuronectes americanus). Native Lv was found to be a mixture of heat-stable and heat-labile molecules in mature, ovulated eggs. A heat-stable Lv fraction was purified from extracts of unfertilized eggs by brief heat treatment and gel permeation chromatography on Bio-Gel A-1.5. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of heat-stable Lv revealed a single polypeptide of 94 kD, while native Lv also possessed several smaller polypeptides, suggesting that heat-labile Lv contains proteolytic cleavages of the 94-kD polypeptide which destabilize its structure. The Stokes radius of the native protein on Bio-Gel A-1.5 was estimated at 4.50 nm, while the Stokes radii of heat-stable and heat-labile Lv were 4.26 nm and 5.17 nm, respectively. Heat-stable Lv was used to produce a rabbit polyclonal antiserum which reacted with a single 175-kD polypeptide in Western blots of vitellogenic female winter flounder serum, but did not react with any component of male serum. Ouchterlony double diffusion using this antiserum demonstrated immunological identity of Lv, heat-stable Lv, and Vg. The anti-Lv anti-serum was used to construct an homologous ELISA with a linear response between 25 and 300 ng/ml. This assay was used to characterize a Bio-Gel A-1.5 column profile of serum from an estradiol-treated male winter flounder, and a single peak, with Stokes radius of 6.70 nm, was identified as Vg. Winter flounder Vg was confirmed to be a dimer, while Lv from mature eggs was found to be a monomer of a lower molecular weight polypeptide. (C) 1997 Wiley-Liss, Inc. C1 UNIV MASSACHUSETTS,DEPT BIOL,MOL & CELLULAR BIOL PROGRAM,AMHERST,MA 01003. NOAA,NATL MARINE FISHERIES SERV,MILFORD LAB,MILFORD,CT 06460. OI Kunkel, Joseph/0000-0003-4070-5606 NR 48 TC 20 Z9 22 U1 1 U2 2 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0022-104X J9 J EXP ZOOL JI J. Exp. Zool. PD JUN 15 PY 1997 VL 278 IS 3 BP 156 EP 166 DI 10.1002/(SICI)1097-010X(19970615)278:3<156::AID-JEZ5>3.0.CO;2-N PG 11 WC Zoology SC Zoology GA XE033 UT WOS:A1997XE03300005 PM 9181695 ER PT J AU Woicik, JC Bouldin, CE Miyano, KE King, CA AF Woicik, JC Bouldin, CE Miyano, KE King, CA TI Unit cell of strained GeSi SO PHYSICAL REVIEW B LA English DT Article ID ABSORPTION FINE-STRUCTURE; BOND-LENGTH RELAXATION; SI1-XGEX ALLOYS; SILICON; LAYERS AB The local structure within the unit cell of strained-GeSi layers grown on Si(001) has been examined by polarization-dependent extended x-ray-absorption fine structure. First-neighbor bond lengths are found to deviate only slightly from their unstrained values; however, the distortion of the cubic-unit cell by strain leads to measurable polarization-dependent changes in first-shell coordination and second-shell distances. A unifying picture of bond lengths and elasticity in strained-layer semiconductors is presented. C1 CUNY BROOKLYN COLL,DEPT PHYS,BROOKLYN,NY 11210. AT&T BELL LABS,LUCENT TECHNOL,MURRAY HILL,NJ 07974. RP Woicik, JC (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 17 TC 32 Z9 32 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1997 VL 55 IS 23 BP 15386 EP 15389 DI 10.1103/PhysRevB.55.15386 PG 4 WC Physics, Condensed Matter SC Physics GA XH335 UT WOS:A1997XH33500012 ER PT J AU Clark, CW AF Clark, CW TI Closed-form solutions of the Schrodinger equation for a class of smoothed Coulomb potentials SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID LASER FIELDS; IONIZATION; ATOM AB An infinite family of closed-form solutions is exhibited for the Schrodinger equation for the potential V(r) = -Z/root\r\(2)+a(2). Evidence is presented for an approximate dynamical symmetry for large values of the angular momentum l. RP Clark, CW (reprint author), US DEPT COMMERCE,NATL INST STAND & TECHNOL,DIV ELECTRON & OPT PHYS,TECHNOL ADM,GAITHERSBURG,MD 20899, USA. RI Clark, Charles/A-8594-2009 OI Clark, Charles/0000-0001-8724-9885 NR 14 TC 11 Z9 11 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUN 14 PY 1997 VL 30 IS 11 BP 2517 EP 2527 DI 10.1088/0953-4075/30/11/006 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XF690 UT WOS:A1997XF69000006 ER PT J AU Parson, R Faeder, J AF Parson, R Faeder, J TI Ultrafast reaction dynamics in molecular cluster ions SO SCIENCE LA English DT Editorial Material ID RECOMBINATION DYNAMICS; VIBRATIONAL-RELAXATION; CHARGE FLOW; PHOTODISSOCIATION; I2 C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Parson, R (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 13 TC 15 Z9 15 U1 0 U2 6 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 13 PY 1997 VL 276 IS 5319 BP 1660 EP 1661 DI 10.1126/science.276.5319.1660 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA XD947 UT WOS:A1997XD94700030 ER PT J AU Wenthold, PG Kim, JB Jonas, KL Lineberger, WC AF Wenthold, PG Kim, JB Jonas, KL Lineberger, WC TI An experimental and computational study of the electron affinity of boron oxide SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SET MODEL CHEMISTRY; BO; PHOTODETACHMENT; MONOXIDE; ABINITIO; OXYGEN AB The 351 nm photoelectron spectrum of BO- is reported. Detachment to form (2) Sigma(+) BO is observed, and the electron affinity of BO is determined to be 2.508 +/- 0.008 eV. From the photoelectron spectra, vibrational frequencies of 1875 +/- 30 cm(-1) and 1665 +/- 30 cm(-1) are obtained for <(X)over tilde BO> and BO-, respectively, and the bond length in BO- is found to be 1.236 +/- 0.010 Angstrom. The measured EA is used to derive a bond energy in BO- of 9.39 eV. High-level molecular orbital calculations of the electron affinity are reported. The results from multiconfigurational SCF, G2, and complete basis set calculations are in good agreement with experiment. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Wenthold, PG (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 34 TC 41 Z9 42 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 12 PY 1997 VL 101 IS 24 BP 4472 EP 4474 DI 10.1021/jp970645u PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XD906 UT WOS:A1997XD90600022 ER PT J AU Tewari, YB Goldberg, RN Sato, M AF Tewari, YB Goldberg, RN Sato, M TI Thermodynamics of the hydrolysis and cyclization reactions of alpha-, beta-, and gamma-cyclodextrin SO CARBOHYDRATE RESEARCH LA English DT Article DE alpha-, beta-, and gamma-cyclodextrin; cyclomaltodextrin glucanotransferase; enthalpies of reaction; equilibrium constants; thermodynamics ID HEAT-CAPACITIES; MODEL AB A thermodynamic investigation of the hydrolysis and cyclization reactions of cyclomaltohexa-, hepta, and octa-ose (alpha-, beta-, and gamma-cyclodextrins) has been performed using microcalorimetry and high-performance liquid-chromatography. The calorimetric measurements lead to standard molar enthalpy changes Delta(r)H(m) degrees (T = 298.15 K, KH2PO4 buffer (m = 0.10 mol kg(-1), pH = 4.58 to 5.15) for the following reactions: alpha-cyclodextrin(aq) + 6 H2O(1) = 6 D-glucose(aq), beta-cyclodextrin(aq) + 7 H2O(1) = 7 D-glucose(aq), gamma-cyclodextrin(aq) + 8 H2O(1) = 8 D-glucose(aq). Equilibrium constants were determined for the following generalized cyclization reactions (T = 329.6 K, 0.005 mol kg(-1) K-2 HPO4 buffer adjusted to pH = 5.55 with H3PO4) catalyzed by cyclomaltodextrin glucanotransferase: G(u)(aq) = alpha-cyclodextrin(aq) + G((u-6))(aq), G(v)(aq) = beta-cyclodextrin(aq) + G(v-7)(aq), G(w)(aq) = gamma-cyclodextrin(aq) + G((w-8))(aq). Here, G(1) is D-glucose and the G(n)'s (n is a positive integer) are linear maltodextrins; u, v, and w are, respectively, integers greater than or equal to 7, greater than or equal to 8, and greater than or equal to 9. Values of the equilibrium constants, standard molar Gibbs energy change Delta(r)G(m) degrees, standard molar enthalpy change Delta(r)H(m) degrees, standard molar entropy change Delta(r)S(m) degrees, and standard molar heat-capacity change Delta(r)C(p,m)degrees are tabulated for the above reactions at T = 298.15 K. The values of Delta(r)G(m) degrees and Delta(r)S(m) degrees for the first three above-mentioned reactions rely upon an estimated value of Delta(r)S(m) degrees for the hydrolysis reaction of maltose to D-glucose. The thermodynamics of the disproportionation reaction G(m)(aq) + G(n)(aq) = G(m-1)(aq) + G(n+1)(aq) is also discussed. Values of the quantities Delta(r)H(m) degrees/N, Delta(r)G(m) degrees/N, Delta(r)S(m) degrees/N, and Delta(r)C(p,m)degrees/N for the three above-mentioned hydrolysis reactions where N is the number of (1 --> 4)-alpha-D-glucosidic bonds broken in each of these reactions, have been calculated and compared with thermodynamic quantities for the similar hydrolysis reaction of a linear oligosaccharide. (C) 1997 Elsevier Science Ltd. C1 MERCIAN CORP, FUJISAWA, KANAGAWA 251, JAPAN. RP Tewari, YB (reprint author), NIST, DIV BIOTECHNOL, GAITHERSBURG, MD 20899 USA. NR 17 TC 13 Z9 13 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0008-6215 EI 1873-426X J9 CARBOHYD RES JI Carbohydr. Res. PD JUN 11 PY 1997 VL 301 IS 1-2 BP 11 EP 22 DI 10.1016/S0008-6215(97)00073-6 PG 12 WC Biochemistry & Molecular Biology; Chemistry, Applied; Chemistry, Organic SC Biochemistry & Molecular Biology; Chemistry GA XH463 UT WOS:A1997XH46300003 PM 9228736 ER PT J AU Lory, S Strom, MS AF Lory, S Strom, MS TI Structure-function relationship of type-IV prepilin peptidase of Pseudomonas aeruginosa - A review SO GENE LA English DT Article; Proceedings Paper CT Symposium on Type-4 pili:Biogenesis, Adhesins, Protein Export and DNA Import CY NOV 26-29, 1995 CL ROTTACH EGERN, GERMANY SP Alexander von Humboldt Fdn, Max Planck Gesell DE leader peptidase; pilin; MTase; S-adenosylmethionine; protein secretion ID GRAM-NEGATIVE BACTERIA; SECRETION PATHWAY; NEISSERIA-GONORRHOEAE; PULLULANASE SECRETION; PROTEIN-SECRETION; MOLECULAR-CLONING; ESCHERICHIA-COLI; LEADER PEPTIDASE; GENES; PILD AB The bifunctional enzyme prepilin peptidase (PilD) from Pseudomonas aeruginosa is a key determinant in both type-IV pilus biogenesis and extracellular protein secretion, in its roles as a leader peptidase and MTase. It is responsible for endopeptidic cleavage of the unique leader peptides that characterize type-IV pilin precursors, as well as proteins with homologous leader sequences that are essential components of the general secretion pathway found in a variety of Gram-negative pathogens. Following removal of the leader peptides, the same enzyme is responsible for the second posttranslational modification that characterizes the type-IV pilins and their homologues, namely N-methylation of the newly exposed N-terminal amino acid residue. This review discusses some of the work begun in order to answer questions regarding the structure-function relationships of the active sites of this unique enzyme. (C) 1997 Elsevier Science B.V. C1 NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,UTILIZAT RES DIV,SEATTLE,WA 98112. RP Lory, S (reprint author), UNIV WASHINGTON,DEPT MICROBIOL,BOX 357242,SEATTLE,WA 98195, USA. FU NIAID NIH HHS [AI 21451] NR 26 TC 66 Z9 70 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-1119 J9 GENE JI Gene PD JUN 11 PY 1997 VL 192 IS 1 BP 117 EP 121 DI 10.1016/S0378-1119(96)00830-X PG 5 WC Genetics & Heredity SC Genetics & Heredity GA XH496 UT WOS:A1997XH49600015 PM 9224881 ER PT J AU Colle, R Kishore, R AF Colle, R Kishore, R TI An update on the NIST radon-in-water standard generator: Its performance efficacy and long-term stability SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE calibration; emanation; liquid scintillation; measurement; polyethylene; radioactivity; radium-226; radon-222; standard; water ID RN-222 AB A Ra-226-Rn-222 generator that could be used as a transfer standard for radon-in-water measurement calibrations was previously developed and described. The generator utilized a novel Rn-222 emanation source that was comprised of a Ra-226 solution encapsulated in polyethylene. The long-term performance of this standard generator has now been investigated and evaluated. The evaluation included exhaustive and more reliable measurement uncertainty analyses for the generator's performance and routine operation. Modifications to the original protocol for operation of the generator has also resulted in improved precision in the Rn-222 activity concentration in a dispensed aliquant. The evaluation results indicate that the generator performance has remained stable, and that the calibration parameters are still well within their given uncertainty intervals for the originally determined canonical values. Over a period of approximately six years, experimentally determined values of the Rn-222 emanation fraction, the most critical parameter, have remained constant and invariant of conditions within statistical variations of about 0.3% (corresponding to a relative standard deviation of the mean). All evaluation measurements were performed by 4 pi-alpha beta liquid scintillation spectrometry of gravimetrically determined aliquants dispensed from the generator. RP Colle, R (reprint author), NIST,PHYS LAB,GAITHERSBURG,MD 20899, USA. NR 29 TC 9 Z9 9 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 11 PY 1997 VL 391 IS 3 BP 511 EP 528 DI 10.1016/S0168-9002(97)00572-X PG 18 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XM586 UT WOS:A1997XM58600018 ER PT J AU Cherng, A Takagi, S Chow, LC AF Cherng, A Takagi, S Chow, LC TI Effects of hydroxypropyl methylcellulose and other gelling agents on the handling properties of calcium phosphate cement SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article ID HYDROXYAPATITE CEMENT; CHITOSAN AB The calcium phosphate cement (CPC) used in this study was formed by combining equimolar amounts of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA). This powder, when mixed with water, sets to a hard cement in about 30 min. However, the waterbased CPC paste is not highly cohesive and is vulnerable to washout until hardening occurs. The objectives of this study were to investigate the effects on handling properties, washout resistance, cement hardening behavior, and mechanical properties of adding several gelling agents to CPC paste. Aqueous solutions that contained a mass fraction of 2-4% of hydroxypropyl methylcellulose (HPMC), carboxyl methylcellulose (CMC), chitosan acetate, and chitosan lactate were used as cement liquids. Hardening time was measured by the Gilmore needle test; resistance to washout was evaluated by the disintegration of the cement specimen in water with agitation; and mechanical strength was evaluated by the measurement of diametral tensile strength and compressive strength. Handling properties were greatly improved by the addition of HPMC, CMC, chitosan acetate, and chitosan lactate. Hardening time was retarded by the additions of HPMC and CMC, and mechanical strength was weakened by the addition of either the chitosan lactate or the chitosan acetate. (C) 1997 John Wiley & Sons, Inc. RP Cherng, A (reprint author), NATL INST STAND & TECHNOL,PAFFENBARGER RES CTR,AMER DENT ASSOC HLTH FDN,GAITHERSBURG,MD 20899, USA. FU NIDCR NIH HHS [DE 05030, DE 11789] NR 19 TC 105 Z9 110 U1 3 U2 15 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD JUN 5 PY 1997 VL 35 IS 3 BP 273 EP 277 DI 10.1002/(SICI)1097-4636(19970605)35:3<273::AID-JBM1>3.0.CO;2-E PG 5 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA WW450 UT WOS:A1997WW45000001 PM 9138061 ER PT J AU de Bievre, P Kaarls, R Peiser, HS Rasberry, SD Reed, WP AF de Bievre, P Kaarls, R Peiser, HS Rasberry, SD Reed, WP TI Protocols for traceability in chemical analysis - Part I: Definitions and terminology SO ACCREDITATION AND QUALITY ASSURANCE LA English DT Review AB The authors propose definitions and terminology for protocols on traceability links, generally to the international system of units, for specific chemical-analytical measurements in accordance with recognized principles of science. These definitions and terms could be useful in science, technology, commerce or law. A chain of such links leads from a measurand in a sample up to a unit in the International System of Units or? if unavailable, to a value on an internationally recognized measurement scale.;The quality of such a chain is quantified by combining all recognized uncertainties estimated for all its links. These uncertainties of the measured values arise from many potential error sources. The protocols should give details of specific uses of reference materials, measuring instruments and standard measurement methods. C1 Commiss European Communities, Joint Res Ctr, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. Netherlands Measurements Inst, NL-2600 AR Delft, Netherlands. NIST, Rockville, MD 20850 USA. NIST, Gaithersburg, MD 20899 USA. RP de Bievre, P (reprint author), Commiss European Communities, Joint Res Ctr, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. NR 19 TC 18 Z9 18 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0949-1775 J9 ACCREDIT QUAL ASSUR JI Accredit. Qual. Assur. PD JUN PY 1997 VL 2 IS 4 BP 168 EP 179 DI 10.1007/s007690050126 PG 12 WC Chemistry, Analytical; Instruments & Instrumentation SC Chemistry; Instruments & Instrumentation GA YX254 UT WOS:000072021800002 ER PT J AU Thomson, DS Middlebrook, AM Murphy, DM AF Thomson, DS Middlebrook, AM Murphy, DM TI Thresholds for laser-induced ion formation from aerosols in a vacuum using ultraviolet and vacuum-ultraviolet laser wavelengths SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID SULFURIC-ACID; SPHERICAL-PARTICLE; MASS-SPECTROMETRY AB The minimum laser fluence required for the formation of ions from aerosol particles in a vacuum as a function of a number of parameters has been investigated. Although the influences of various particle properties are complex, the threshold energy density does depend on light absorption and lattice energy. Ionization thresholds were lower at 193 and 157 nm than at 248 nm. The range in ion formation thresholds for different types of particles also decreased as the laser wavelength decreased, consistent with the fact that all the substances used are likely to absorb vacuum-ultraviolet radiation fairly strongly. The threshold for negative ion formation was generally greater than that for positive ion formation. Pure sulfuric acid aerosols were ionized well only at 157 nm. (C) 1997 American Association for Aerosol Research. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Thomson, DS (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Middlebrook, Ann/E-4831-2011; Murphy, Daniel/J-4357-2012 OI Middlebrook, Ann/0000-0002-2984-6304; Murphy, Daniel/0000-0002-8091-7235 NR 31 TC 50 Z9 50 U1 0 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD JUN PY 1997 VL 26 IS 6 BP 544 EP 559 DI 10.1080/02786829708965452 PG 16 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XA222 UT WOS:A1997XA22200005 ER PT J AU Schwabacher, M Gelsey, A AF Schwabacher, M Gelsey, A TI Intelligent gradient-based search of incompletely defined design spaces SO AI EDAM-ARTIFICIAL INTELLIGENCE FOR ENGINEERING DESIGN ANALYSIS AND MANUFACTURING LA English DT Article DE optimization; gradients; sequential quadratic programming; rule-based systems AB Gradient-based numerical optimization of complex engineering designs offers the promise of rapidly producing better designs. However, such methods generally assume that the objective function and constraint functions are continuous, smooth, and defined everywhere. Unfortunately, realistic simulators tend to violate these assumptions. We present a rule-based technique for intelligently computing gradients in the presence of such pathologies in the simulators, and show how this gradient computation method can be used as part of a gradient-based numerical optimization system. We tested the resulting system in the domain of conceptual design of supersonic transport aircraft, and found that using rule-based gradients can decrease the cost of design space search by one or more orders of magnitude. C1 NIST, GAITHERSBURG, MD 20899 USA. RUTGERS STATE UNIV, NEW BRUNSWICK, NJ 08903 USA. NR 32 TC 3 Z9 3 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0890-0604 EI 1469-1760 J9 AI EDAM JI AI EDAM-Artif. Intell. Eng. Des. Anal. Manuf. PD JUN PY 1997 VL 11 IS 3 BP 199 EP 210 PG 12 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary; Engineering, Manufacturing SC Computer Science; Engineering GA XQ043 UT WOS:A1997XQ04300003 ER PT J AU Balthazor, RL Moffett, RJ Millward, GH AF Balthazor, RL Moffett, RJ Millward, GH TI A study of the Joule and Lorentz inputs in the production of atmospheric gravity waves in the upper thermosphere SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article ID PROPAGATION; GENERATION; CURRENTS AB First results of a modelling study of atmospheric gravity waves (AGWs) are presented. A fully-coupled global thermosphere-ionosphere-plasmasphere model is used to examine the relative importance of Lorentz forcing and Joule heating in the generation of AGWs. It is found that Joule heating is the dominant component above 110 km. The effects of the direction of the Lorentz forcing component on the subsequent propagation of the AGW are also addressed. It is found that enhancement of zonal E x B forcing results in AGWs at F-region altitudes of similar magnitudes travelling from the region of forcing in both poleward and equatorward directions, whilst enhancement of equatorward meridional E x B forcing results in AGWs travelling both poleward and equatorward, but with the magnitude of the poleward wave severely attenuated compared with the equatorward wave. C1 UNIV COLORADO,CIRES,NOAA,SPACE ENVIRONM LAB,BOULDER,CO 80303. RP Balthazor, RL (reprint author), UNIV SHEFFIELD,SCH MATH & STAT,UPPER ATMOSPHERE MODELLING GRP,SHEFFIELD S3 7RH,S YORKSHIRE,ENGLAND. OI Balthazor, Richard/0000-0002-4568-7446 NR 18 TC 9 Z9 9 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD JUN PY 1997 VL 15 IS 6 BP 779 EP 785 DI 10.1007/s00585-997-0779-6 PG 7 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA XG445 UT WOS:A1997XG44500022 ER PT J AU Gentile, TR Houston, JM Eppeldauer, G Migdall, AL Cromer, CL AF Gentile, TR Houston, JM Eppeldauer, G Migdall, AL Cromer, CL TI Calibration of a pyroelectric detector at 10.6 mu m with the National Institute of Standards and Technology high-accuracy cryogenic radiometer SO APPLIED OPTICS LA English DT Article AB The National Institute of Standards and Technology (NIST) is establishing an infrared detector calibration facility to improve radiometric standards at infrared wavelengths. The absolute response of the cryogenic bolometer that serves as the transfer standard for this facility is being linked to the NIST high-accuracy cryogenic radiometer (HACR) at a few laser wavelengths. At the 10.6-mu m CO2 laser line, this Link is being established through a pyroelectric detector that has been calibrated against the HACR. We describe the apparatus, methods, and uncertainties for the calibration of this pyroelectric detector. RP Gentile, TR (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 13 TC 10 Z9 10 U1 2 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 1 PY 1997 VL 36 IS 16 BP 3614 EP 3621 DI 10.1364/AO.36.003614 PG 8 WC Optics SC Optics GA XB710 UT WOS:A1997XB71000004 PM 18253383 ER PT J AU Karam, LR Mitch, MG Coursey, BM AF Karam, LR Mitch, MG Coursey, BM TI Encapsulation of Tc-99m within fullerenes: A novel radionuclidic carrier SO APPLIED RADIATION AND ISOTOPES LA English DT Article ID CARBON; ATOMS; CAGES; C-60 AB The nature of fullerenes as miniature 'isolation chambers' suggests the possibility of unstable atoms carried within the interior of the molecular cage forming endofullerenes which could isolate potentially reactive atoms from their environment. We have produced, characterized by various techniques including thin layer chromatography, and purified endofullerenes containing gamma-ray emitting Tc-99m, the first direct encapsulation of a radionuclide during fullerene formation. Identification of Tc-99m@C-60 and Tc-99m@C-70 has been accomplished by application of ultra-low level radiation detection methods. Appropriately derivatized, Tc-99m 'radioendofullerenes' could eventually be used as a radiopharmaceutical for medical imaging. (C) 1997 Published by Elsevier Science Ltd. C1 UNIV MARYLAND,DEPT MAT & NUCL ENGN,COLLEGE PK,MD 20742. RP Karam, LR (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 18 TC 11 Z9 12 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD JUN PY 1997 VL 48 IS 6 BP 771 EP 776 DI 10.1016/S0969-8043(96)00315-6 PG 6 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA XD985 UT WOS:A1997XD98500010 ER PT J AU Colle, R AF Colle, R TI Systematic effects of total cocktail mass (volume) and H2O fraction on 4 pi beta liquid scintillation spectrometry of H-3 SO APPLIED RADIATION AND ISOTOPES LA English DT Article AB Detection efficiencies epsilon Of H-3 by 4 pi beta liquid scintillation (LS) spectrometry systematically vary as a function of both total cocktail mass m and cocktail composition (such as the H2O mass fraction f). Quench indicating parameter (QIP) determinations, such as for the Horrocks number H, are also dependent on m and f. These systematic effects were investigated with a matrix of 33 LS cocktails covering a broad array of m and f values: 3.0 g less than or equal to m less than or equal to 21.4 g and 0.002 less than or equal to f less than or equal to 0.52. The effects of m- and f on the LS background counting rates of matched blanks are also treated in detail. The uncertainties associated with these m and f-dependent effects on epsilon and on H are particularly given close scrutiny. The systematics clearly demonstrate that efficiency changes cannot be adequately monitored by quench indicating parameters when the quench changes are induced by multiple causal factors (e.g. simultaneously varying cocktail sizes and compositions). The experimental results presented here have significant implications on the critical importance of understanding the systematics of these variable effects for a given LS system (combination of cocktails and spectrometer), and of very closely matching LS cocktail volumes and compositions in order to achieve reproducible and accurate LS counting results. (C) 1997 Published by Elsevier Science Ltd. RP Colle, R (reprint author), NIST,PHYS LAB,GAITHERSBURG,MD 20899, USA. NR 8 TC 8 Z9 8 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD JUN PY 1997 VL 48 IS 6 BP 815 EP 831 DI 10.1016/S0969-8043(96)00287-4 PG 17 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA XD985 UT WOS:A1997XD98500015 ER PT J AU Colle, R AF Colle, R TI Cocktail mismatch effects in 4 pi beta liquid scintillation spectrometry: Implications based on the systematics of H-3 detection efficiency and quench indicating parameter variations with total cocktail mass (volume) and H2O fraction SO APPLIED RADIATION AND ISOTOPES LA English DT Article ID COUNTING EFFICIENCY; STANDARDIZATION AB Detection efficiency changes for H-3 by 4 pi beta liquid scintillation (LS) spectrometry cannot be adequately monitored by quench indicating parameters when the quench changes are the result of multiple causal factors (e.g. simultaneously Varying cocktail sizes and composition). In consequence, some kinds of cocktail mismatches (between LS counting sources) introduce errors that result from efficiency changes that cannot be fully accounted for by quench monitoring compensations. These cocktail mismatch effects are examined for comparative H-3 measurements and for H-3-standard efficiency tracing methods for the assay of other beta-emitting radionuclides. Inherent errors can occur in both types of radionuclidic assays, as demonstrated with realistic case examples, unless cocktails are very closely matched. The magnitude of the cocktail mismatch effect (and attendant errors) can range from being virtually negligible (particularly for high-energy beta-emitting nuclides and for slight single-variable cocktail composition mismatches) to be being Very significant for high-precision metrology and standardizations (particularly with easily quenched, low-energy beta emitters and for mismatches due to both varying cocktail constituents and concentrations). The findings presented here support the need to understand fully the quenching systematics of a given LS system (combination of cocktails and spectrometer) and the need for very careful control of cocktail preparations. (C) 1997 Published by Elsevier Science Ltd. RP Colle, R (reprint author), NIST,PHYS LAB,GAITHERSBURG,MD 20899, USA. NR 12 TC 8 Z9 8 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD JUN PY 1997 VL 48 IS 6 BP 833 EP 842 DI 10.1016/S0969-8043(96)00288-6 PG 10 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA XD985 UT WOS:A1997XD98500016 ER PT J AU Emmons, LK Carroll, MA Hauglustaine, DA Brasseur, GP Atherton, C Penner, J Sillman, S Levy, H Rohrer, F Wauben, WMF VanVelthoven, PFJ Wang, Y Jacob, D Bakwin, P Dickerson, R Doddridge, B Gerbig, C Honrath, R Hubler, G Jaffe, D Kondo, Y Munger, JW Torres, A VolzThomas, A AF Emmons, LK Carroll, MA Hauglustaine, DA Brasseur, GP Atherton, C Penner, J Sillman, S Levy, H Rohrer, F Wauben, WMF VanVelthoven, PFJ Wang, Y Jacob, D Bakwin, P Dickerson, R Doddridge, B Gerbig, C Honrath, R Hubler, G Jaffe, D Kondo, Y Munger, JW Torres, A VolzThomas, A TI Climatologies of NOx and NOy: A comparison of data and models SO ATMOSPHERIC ENVIRONMENT LA English DT Review ID GENERAL-CIRCULATION MODEL; ARCTIC STRATOSPHERIC EXPEDITION; OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; REACTIVE ODD-NITROGEN; GLOBAL LIGHTNING DISTRIBUTIONS; NITRIC-OXIDE MEASUREMENTS; TRACE GAS CONCENTRATIONS; GASEOUS DRY DEPOSITION; SEASONAL-VARIATION; UPPER TROPOSPHERE AB Climatologies of tropospheric NOx(NO + NO2) and NOy (total reactive nitrogen: NOx + NO3 + 2 x N2O5 + HNO2 + HNO3 + HNO4 + ClONO2 + PAN (peroxyacetylnitrate) + other organic nitrates) have been compiled from data previously published and, in most cases, publicly archived. Emphasis has been on non-urban measurements, including rural and remote ground sites, as well as aircraft data. Although the distribution of data is sparse, a compilation in this manner can begin to provide an understanding of the spatial and temporal distributions of these reactive nitrogen species. The cleanest measurements in the boundary layer are in Alaska, northern Canada and the eastern Pacific, with median NO mixing ratios below 10 pptv, NOx below 50 pptv, and NOy below 300 pptv. The highest NO values (greater than 1 ppbv) were found in eastern North America and Europe, with correspondingly high NOy (similar to 5 ppbv). A significantly narrower range of concentrations is seen in the free troposphere, particularly at 3-6 km, with NO typically about 10 pptv in the boreal summer. NO increases with altitude to similar to 100 pptv at 9-12 km, whereas NOy does not show a trend with altitude, but varies between 100 and 1000 pptv. Decreasing mixing ratios eastward of the Asian and North American continents are seen in all three species at all altitudes. Model-generated climatologies of NOx and NOy from six chemical transport models are also presented and are compared with observations in the boundary layer and the middle troposphere for summer and winter. These comparisons test our understanding of the chemical and transport processes responsible for these species distributions. Although the model results show differences between them, and disagreement with observations, none are systematically different for all seasons and altitudes. Some of the differences between the observations and model results may likely be attributed to the specific meteorological conditions at the time that measurements were made differing from the model meteorology, which is either climatological how from GCMs or actual meteorology for an arbitrary year. Differences in emission inventories, and convection and washout schemes in the models will also affect the calculated NOx and NOy distributions. (C) 1997 Elsevier Science Ltd. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA USA. PRINCETON UNIV, NOAA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08542 USA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, ICG, JULICH, GERMANY. ROYAL NETHERLANDS METEOROL INST, NL-3730 AE DE BILT, NETHERLANDS. HARVARD UNIV, CAMBRIDGE, MA 02138 USA. NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. UNIV MARYLAND, COLLEGE PK, MD 20742 USA. MICHIGAN TECHNOL UNIV, HOUGHTON, MI 49931 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. UNIV ALASKA, FAIRBANKS, AK 99701 USA. NAGOYA UNIV, NAGOYA, AICHI, JAPAN. NASA, WALLOPS FLIGHT FACIL, WALLOPS ISL, VA USA. RP Emmons, LK (reprint author), UNIV MICHIGAN, DEPT ATMOSPHER OCEAN & SPACE SCI, ANN ARBOR, MI 48109 USA. RI Hubler, Gerhard/E-9780-2010; Dickerson, Russell/F-2857-2010; Kondo, Yutaka/D-1459-2012; Rohrer, Franz/I-2052-2012; Gerbig, Christoph/L-3532-2013; Wang, Yuhang/B-5578-2014; Volz-Thomas, Andreas/J-7223-2012; Munger, J/H-4502-2013; Emmons, Louisa/R-8922-2016; OI Dickerson, Russell/0000-0003-0206-3083; Rohrer, Franz/0000-0003-3436-3419; Gerbig, Christoph/0000-0002-1112-8603; Volz-Thomas, Andreas/0000-0003-3700-1667; Munger, J/0000-0002-1042-8452; Emmons, Louisa/0000-0003-2325-6212; Sillman, Sanford/0000-0001-6250-1191 NR 176 TC 93 Z9 95 U1 0 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUN PY 1997 VL 31 IS 12 BP 1851 EP 1904 DI 10.1016/S1352-2310(96)00334-2 PG 54 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA WU835 UT WOS:A1997WU83500009 ER PT J AU Grachev, AA Fairall, CW Zilitinkevich, SS AF Grachev, AA Fairall, CW Zilitinkevich, SS TI Surface-layer scaling for the convection-induced stress regime SO BOUNDARY-LAYER METEOROLOGY LA English DT Article DE surface layer; free convection; roughness length ID PLANETARY BOUNDARY-LAYER; VELOCITY SPECTRA; HEAT FLUX; SEA AB The Prandtl, Obukhov, and Monin and Obukhou similarity theories are widely used to describe the structure of turbulence in the atmospheric surface layer. Currently it is understood that in strong convection with no or very weak mean wind the traditional theory breaks down. In particular, the traditional theory implies a single-valued correspondence between local turbulence statistics and local properties of the flow. In very strong convection, this is not true because of large-scale (similar to 10(3) m) coherent structures, embracing the entire convective boundary layer (CBL). These structures produce random gusts that crucially affect surface-layer turbulence and make it dependent on global properties of the flow, such as the CBL depth. In the present paper the limits of validity of the traditional surface-layer similarity theory are determined and a revised theory of fair weather convection in the surface layer is developed by considering the effect of gustiness. It is shown that the theoretical predictions are consistent with field data from the TOGA COARE and SCOPE experiments. C1 NOAA,ERL,ETL,BOULDER,CO 80303. ALFRED WEGENER INST POLAR & MARINE RES,D-27570 BREMERHAVEN,GERMANY. MAX PLANCK INST METEOROL,D-20146 HAMBURG,GERMANY. RP Grachev, AA (reprint author), RUSSIAN ACAD SCI,INST ATMOSPHER PHYS,PYZHEVSKY 3,MOSCOW 109017,RUSSIA. OI Zilitinkevich, Sergej/0000-0002-3909-5436; GRACHEV, ANDREY/0000-0002-7143-0820 NR 34 TC 21 Z9 21 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0006-8314 J9 BOUND-LAY METEOROL JI Bound.-Layer Meteor. PD JUN PY 1997 VL 83 IS 3 BP 423 EP 439 DI 10.1023/A:1000281625985 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH608 UT WOS:A1997XH60800004 ER PT J AU Meekhof, DM Leibfried, D Monroe, C King, BE Itano, WM Wineland, DJ AF Meekhof, D. M. Leibfried, D. Monroe, C. King, B. E. Itano, W. M. Wineland, D. J. TI Experimental Creation and Measurement of Motional Quantum States of a Trapped Ion SO BRAZILIAN JOURNAL OF PHYSICS LA English DT Article AB We report the creation and full determination of several quantum states of motion of a Be-9(+) ion bound in a rf (Paul) trap. The states are coherently prepared from an ion which has been initially laser cooled to the zero-point of motion. We create states having both classical and nonclassical character including thermal, number, coherent, squeezed, and "Schrodinger cat" states. The motional quantum state is fully reconstructed using two novel schemes that determine the density matrix in the number state basis or the Wigner-function. Our techniques allow well controlled experiments on decoherence and related phenomena on the quantum-classical borderline. C1 [Meekhof, D. M.; Leibfried, D.; Monroe, C.; King, B. E.; Itano, W. M.; Wineland, D. J.] NIST, Boulder, CO 80303 USA. RP Meekhof, DM (reprint author), NIST, 325 Broadway, Boulder, CO 80303 USA. RI Monroe, Christopher/G-8105-2011 FU United States National Security Agency; Office of Naval Research; Army Research Office; Deutsche Forschungsgemeinschaft; N.R.C. FX This work is supported by the United States National Security Agency, the Office of Naval Research and the Army Research Office. D. L. gratefully acknowledges a Deutsche Forschungsgemeinschaft research grant. D. M. M. is supported by a N.R.C. postdoctoral fellowship. We thank W. Vogel, M. Collet, P. Knight, J.I. Cirac and P. Zoller for stimulating discussions. We acknowledge important contributions by J. Bergquist and helpful comments on the manuscript by M. Young, B. Esry and B. Jelenkovic. NR 56 TC 3 Z9 3 U1 1 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0103-9733 EI 1678-4448 J9 BRAZ J PHYS JI Braz. J. Phys. PD JUN PY 1997 VL 27 IS 2 BP 178 EP 192 PG 15 WC Physics, Multidisciplinary SC Physics GA V32LM UT WOS:000208952700015 ER PT J AU Karl, TR Knight, RW AF Karl, TR Knight, RW TI The 1995 Chicago heat wave: How likely is a recurrence? SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID TEMPERATURE; CLIMATE; MAXIMUM AB The deadly heat wave of July 1995 that affected much of the U.S. midwest, most notably Chicago, Illinois, has been put into historical perspective. The heat wave has been found to be remarkably unusual, but only partially because of the extreme high apparent temperatures (an index of the combined effect of temperature and humidity on humans), when the authors calculate a return period of the peak apparent temperature of less than or equal to 23 yr. Of greater significance were the very high temperatures that persisted day and night over an extended 48-h period. Analysis presented here indicates that for Chicago such an extended period of continuously high day and night apparent temperature is unprecedented in modem times. The 2-day period where the minimum apparent temperature failed to go below 31.5 degrees C (89 degrees F) is calculated to be an extremely rare event (probability of occurrence < 0.1%) based on a 10 000-yr-long simulation of a four-parameter (temperatures related to the mean, the intraseasonal daily variance, the interannual variance, and the day-to-day persistence of temperature) probabilistic model. Such unusual heat waves evoke questions related to the future course of the climate and whether this recent event was merely an extreme anomaly or part of an ongoing trend toward more extreme heat waves. A Monte Carlo analysis of trends (1948-95) for various quantiles of the hourly apparent temperatures during the most severe heat waves each year from 26 midwestern stations reveals a modest, statistically insignificant increase of apparent temperatures for a wide range of quantiles without the inclusion of 1995 data. There is a statistically significant increase in apparent temperature with its inclusion, reflected most strongly for upper quantiles or daytime temperatures. It is argued, however, that because of the impact of changes in instrumentation at primary National Weather Service stations, the potential affects of urbanization, and little trend of summer mean temperatures, it is unlikely that the macroscale climate of heat waves in the Midwest or in Chicago is changing in any significant manner. Trends notwithstanding, the authors demonstrate the difficulty associated with projecting changes in the frequency and severity of similar types of events, even if the mean apparent temperature could be accurately predicted for the next century, for example, global warming projections. This is demonstrated using Chicago temperatures. The authors show that accurate projections of the frequency, severity, and duration of heat waves in the Midwest require accurate projections not only of the mean, the interannual variance, the intraseasonal variance, and day-to-day persistence, but also the interrelationships among these quantities within different synoptic-climatic regimes. RP Karl, TR (reprint author), NOAA,NESDIS,NATL CLIMAT DATA CTR,151 PATTON AVE,ASHEVILLE,NC 28801, USA. NR 21 TC 105 Z9 106 U1 0 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1997 VL 78 IS 6 BP 1107 EP 1119 DI 10.1175/1520-0477(1997)078<1107:TCHWHL>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH868 UT WOS:A1997XH86800006 ER PT J AU Nieman, SJ Menzel, WP Hayden, CM Gray, D Wanzong, ST Velden, CS Daniels, J AF Nieman, SJ Menzel, WP Hayden, CM Gray, D Wanzong, ST Velden, CS Daniels, J TI Fully automated cloud-drift winds in NESDIS operations SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID FIELDS AB Cloud-drift winds have been produced from geostationary satellite data in the Western Hemisphere since the early 1970s. During the early years, winds were used as an aid for the short-term forecaster in an era when numerical forecasts were often of questionable quality, especially over oceanic regions. Increased computing resources over the last two decades have led to significant advances in the performance of numerical forecast models. As a result, continental forecasts now stand to gain little from the inspection or assimilation of cloud-drift wind fields. However, the oceanic data void remains, and although numerical forecasts in such areas have improved, they still suffer from a lack of in situ observations. During the same two decades, the quality of geostationary satellite data has improved considerably, and the cloud-drift wind production process has also benefited from increased computing power. As a result, fully automated wind production is now possible, yielding cloud-drift winds whose quality and quantity is sufficient to add useful information to numerical model forecasts in oceanic and coastal regions. This article will detail the automated cloud-drift wind production process, as operated by the National Environmental Satellite Data and Information Service within the National Oceanic and Atmospheric Administration. C1 NOAA,NESDIS,MADISON,WI. NOAA,NESDIS,CAMP SPRINGS,MD. RP Nieman, SJ (reprint author), UNIV WISCONSIN,CIMSS,1225 W DAYTON ST,MADISON,WI 53706, USA. RI Menzel, W. Paul/B-8306-2011; Daniels, Jaime/E-7933-2011 OI Menzel, W. Paul/0000-0001-5690-1201; Daniels, Jaime/0000-0002-9438-6631 NR 24 TC 83 Z9 92 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1997 VL 78 IS 6 BP 1121 EP 1133 DI 10.1175/1520-0477(1997)078<1121:FACDWI>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH868 UT WOS:A1997XH86800007 ER PT J AU Manabe, S Stouffer, RJ AF Manabe, S Stouffer, RJ TI Climate variability of a coupled ocean-atmosphere-land surface model: Implication for the detection of global warming - The Walter Orr Roberts lecture SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article; Proceedings Paper CT Special Symposium on the Land Atmosphere System: An Interdisciplinary Approach at the 77th Annual Meeting of the American-Meteorological-Society CY FEB 04-05, 1997 CL LONG BEACH, CA SP Amer Meteorol Soc AB This lecture evaluates the low-frequency variability of surface air temperature that was obtained from a 1000-yr integration of a coupled ocean-atmosphere-land surface model. The model simulates reasonably well the variability of local and global mean surface air temperature (SAT) at decadal timescales. The physical mechanisms responsible for this variability are explored. Based upon an analysis of the time series of the simulated global mean SAT, it is indicated that the warming trend of similar to 0.5 degrees C century(-1) since the end of the last century was not generated internally through the interaction among the atmosphere, ocean, and land surface. Instead, it appears to have been induced by a sustained change in the thermal forcing such as that resulting from changes in atmospheric greenhouse gas concentration, solar irradiance, and aerosol loading. RP Manabe, S (reprint author), PRINCETON UNIV,NOAA,GEOPHYS FLUID DYNAM LAB,PRINCETON,NJ 08544, USA. NR 16 TC 8 Z9 8 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1997 VL 78 IS 6 BP 1177 EP 1185 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH868 UT WOS:A1997XH86800012 ER PT J AU Laidig, TE Adams, PB Silberberg, KR Fish, HE AF Laidig, TE Adams, PB Silberberg, KR Fish, HE TI Conversions between total, fork, and standard lengths for lingcod, Ophiodon elongatus SO CALIFORNIA FISH AND GAME LA English DT Article C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon, CA 94920 USA. RP Laidig, TE (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, 3150 Paradise Dr, Tiburon, CA 94920 USA. NR 2 TC 3 Z9 3 U1 0 U2 1 PU CALIF FISH AND GAME EDITOR PI SACRAMENTO PA 1416 NINTH ST, SACRAMENTO, CA 95814 USA SN 0008-1078 J9 CALIF FISH GAME JI Calif. Fish Game PD SUM PY 1997 VL 83 IS 3 BP 128 EP 129 PG 2 WC Fisheries; Zoology SC Fisheries; Zoology GA ZG021 UT WOS:000072956800004 ER PT J AU Ansara, I Chart, TG Guillermet, AF Hayes, FH Kattner, UR Pettifor, DG Saunders, N Zeng, K AF Ansara, I Chart, TG Guillermet, AF Hayes, FH Kattner, UR Pettifor, DG Saunders, N Zeng, K TI Thermodynamic modelling of solutions and alloys - Schloss Ringberg, March 10 to March 16, 1996 - Group 2: Alloy system I - Thermodynamic modelling of selected topologically close-packed intermetallic compounds SO CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY LA English DT Article; Proceedings Paper CT Ringberg Workshop 1996 on Solution Modelling CY 1996 CL RINGBERG CASTLE, GERMANY SP Max Planck Gesell ID COUPLED PHASE-DIAGRAMS; METAL BINARY-SYSTEMS; REGULAR SOLUTION MODEL; CR-ZR SYSTEM; SIGMA-PHASE; THERMOCHEMICAL DATA; ATOM DISTRIBUTIONS; TI SYSTEM; NB SYSTEM; TA SYSTEM C1 CHART ASSOCIATES,ASHFORD,KENT,ENGLAND. CONSEJO NACL INVEST CIENT & TECN,CTR ATOM BARILOCHE,SAN CARLOS BARILO,RIO NEGRO,ARGENTINA. UNIV MANCHESTER,MANCHESTER,LANCS,ENGLAND. UMIST,MATER SCI CTR,MANCHESTER M60 1QD,LANCS,ENGLAND. NIST,DIV MET,MSEL,GAITHERSBURG,MD 20899. UNIV OXFORD,DEPT MAT,OXFORD OX1 3PH,ENGLAND. THERMOTECH LTD,GUILDFORD,SURREY,ENGLAND. TECH UNIV CLAUSTHAL,AG ELEKTRON MATER,CLAUSTHAL ZELLERF,GERMANY. RP Ansara, I (reprint author), LAB THERMODYN PHYS CHIM MET,DOMAINE UNIV,ST MARTIN DHER,FRANCE. NR 118 TC 101 Z9 103 U1 0 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0364-5916 J9 CALPHAD JI Calphad-Comput. Coupling Ph. Diagrams Thermochem. PD JUN PY 1997 VL 21 IS 2 BP 171 EP 218 PG 48 WC Thermodynamics; Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Thermodynamics; Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA YJ929 UT WOS:A1997YJ92900004 ER PT J AU Hillert, M Burton, B Saxena, SK Degterov, S Kumar, KCH Ohtani, H Aldinger, F Kussmaul, A AF Hillert, M Burton, B Saxena, SK Degterov, S Kumar, KCH Ohtani, H Aldinger, F Kussmaul, A TI Workshop on thermodynamic modelling of solutions and alloys - Schloss Ringberg, March 10-16, 1996 - Group 4: Modeling of oxides SO CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY LA English DT Article; Proceedings Paper CT Ringberg Workshop 1996 on Solution Modelling CY 1996 CL RINGBERG CASTLE, GERMANY SP Max Planck Gesell ID ORDER C1 NIST,GAITHERSBURG,MD 20899. UPPSALA UNIV,UPPSALA,SWEDEN. ECOLE POLYTECH,MONTREAL,PQ H3C 3A7,CANADA. KATHOLIEKE UNIV LEUVEN,B-3001 LOUVAIN,BELGIUM. TOHOKU UNIV,SENDAI,MIYAGI 980,JAPAN. MAX PLANCK INST,STUTTGART,GERMANY. RP Hillert, M (reprint author), ROYAL INST TECHNOL,S-10044 STOCKHOLM,SWEDEN. RI Kumar, K.C. Hari/D-3123-2012 NR 7 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0364-5916 J9 CALPHAD JI Calphad-Comput. Coupling Ph. Diagrams Thermochem. PD JUN PY 1997 VL 21 IS 2 BP 247 EP 263 PG 17 WC Thermodynamics; Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Thermodynamics; Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA YJ929 UT WOS:A1997YJ92900006 ER PT J AU Merrick, RL Chumbley, MK Byrd, GV AF Merrick, RL Chumbley, MK Byrd, GV TI Diet diversity of Steller sea lions (Eumetopias jubatus) and their population decline in Alaska: a potential relationship SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID SCATS AB We examined the diet of Steller sea lions (Eumetopias jubatus) during June-August 1990-1993 from six areas in the Aleutian Islands and Gulf of Alaska and related these diets to sea lion population changes that occurred during the period. Seven general prey categories were identified, but either walleye pollock (Theragra chalcogramma) or Atka mackerel (Pleurogrammus monopterygius) dominated in every area. The diversity of prey consumed varied among sites. Only the eastern Aleutian Islands area had all seven categories in the diet, and there, walleye pollock and Atka mackerel each made up around 30% of the diet. The remainder was composed mostly of small schooling fish (e.g., Pacific herring (Clupea pallasi) and salmon (Oncorhynchus spp.)). The diet in the Gulf of Alaska included mostly walleye pollock whereas the central and western Aleutian diet was composed mostly of Atka mackerel. Populations in the six areas decreased up to 49% during 1990-1994. A strong positive correlation (r = 0.949, P = 0.004) was found between diet diversity and the amount of decline in an area: as diet diversity decreased, populations decreased. This suggests that sea lions need a variety of prey available, perhaps to buffer significant changes in abundance of any single prey. C1 US FISH & WILDLIFE SERV,ALASKA MARITIME NATL WILDLIFE REFUGE,HOMER,AK 99603. RP Merrick, RL (reprint author), NATL MARINE MAMMAL LAB,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. NR 32 TC 134 Z9 141 U1 0 U2 26 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD JUN PY 1997 VL 54 IS 6 BP 1342 EP 1348 DI 10.1139/cjfas-54-6-1342 PG 7 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XR889 UT WOS:A1997XR88900014 ER PT J AU Marty, GD Heintz, RA Hinton, DE AF Marty, GD Heintz, RA Hinton, DE TI Histology and teratology of pink salmon larvae near the time of emergence from gravel substrate in the laboratory SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID SEX-DIFFERENTIATION; FRY AB During salmonid larval development, emergence from gravel substrate is a major event marked by final yolk absorption and transition to exogenous feeding. The gross and histological changes associated with this fundamental biological process were investigated in pink salmon (Oncorhynchus gorbuscha) 4 weeks before emergence (alevins), at emergence (swim-up fry), and 2 weeks after emergence with or without exogenous feeding. Larvae were derived from artificially spawned eggs reared in gravel-filled incubators in the laboratory. Less than 1% of emergent larvae had gross lesions. These included opercular hypoplasia or dysplasia (semioperculum), spinal anomalies (lordosis and kyphosis), conjoined twins, and ophthalmic dysplasia. Apoptosis, or programmed cell death, was a common cellular change, and several cell types were involved: (i) intragonadal supporting cells, (ii) gastric submucosal gland epithelial cells, and (iii) midventral skin cells. Semiquantitative scores for apoptosis were usually highest in pre-emergent larvae and lowest in postemergent larvae. Larvae that were not fed during the first 2 weeks after emergence had slightly higher scores for apoptosis and hepatocellular megalocytosis than did fed controls. C1 NATL MARINE FISHERIES SERV,AUKE BAY LAB,JUNEAU,AK 99801. RP Marty, GD (reprint author), UNIV CALIF DAVIS,SCH VET MED,DEPT ANAT PHYSIOL & CELL BIOL,DAVIS,CA 95616, USA. NR 23 TC 14 Z9 14 U1 3 U2 14 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD JUN PY 1997 VL 75 IS 6 BP 978 EP 988 DI 10.1139/z97-119 PG 11 WC Zoology SC Zoology GA XC870 UT WOS:A1997XC87000014 ER PT J AU Marty, GD Short, JW Dambach, DM Willits, NH Heintz, RA Rice, SD Stegeman, JJ Hinton, DE AF Marty, GD Short, JW Dambach, DM Willits, NH Heintz, RA Rice, SD Stegeman, JJ Hinton, DE TI Ascites, premature emergence, increased gonadal cell apoptosis, and cytochrome P4501A induction in pink salmon larvae continuously exposed to oil-contaminated gravel during development SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID STENOTOMUS-CHRYSOPS SCUP; MEDAKA ORYZIAS-LATIPES; LAKE TROUT; TISSUES; LIVER; EGGS AB Development of pink salmon (Oncorhynchus gorbuscha) incubating in gravel contaminated with weathered Prudhoe Bay crude oil was retarded at concentrations as low as 55.2 mu g oil/g gravel. Larvae exposed to various levels of oil contamination were sampled 4 weeks before emergence, at emergence, and 13 days after emergence for histopathology (quantitative and semiquantitative) and cytochrome P4501A (CYP1A) induction (using immunohistochemical staining). A subset of postemergent fish was not fed. Hydrocarbon analysis by gas chromatography and mass spectroscopy revealed that tissue uptake of polynuclear aromatic hydrocarbons (PAH) was mediated by oil's dissolution in water, with significant biological effects when the peak total PAH concentration in water was as low as 4.4 mu g/L. Oil-related effects included induction of CYP1A, development of ascites, and increased mortality. Several oil-related changes were indicative of premature emergence. Compared with control fish, for example, exposed fish of the same age and emerging on the same day had greater amounts of yolk and hepatocellular glycogen, increased apoptosis of gonadal cells and midventral skin cells, and less food in the gastrointestinal tract. Histological features were similar within groups of larvae sampled 4 weeks before and 13 days after emergence, and oil-induced changes were not affected by feeding during the first 13 days after emergence. Increased gonadal cell apoptosis may be related to later reproductive impairment documented in field studies of pink salmon up to 4 years after the Exxon Valdez oil spill. C1 NATL MARINE FISHERIES SERV,AUKE BAY LAB,JUNEAU,AK 99801. UNIV PENN,SCH VET MED,DEPT PATHOBIOL,PHILADELPHIA,PA 19104. UNIV CALIF DAVIS,STAT LAB,DAVIS,CA 95616. WOODS HOLE OCEANOG INST,DEPT BIOL,WOODS HOLE,MA 02543. RP Marty, GD (reprint author), UNIV CALIF DAVIS,SCH VET MED,DEPT ANAT PHYSIOL & CELL BIOL,DAVIS,CA 95616, USA. NR 42 TC 117 Z9 121 U1 7 U2 34 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD JUN PY 1997 VL 75 IS 6 BP 989 EP 1007 DI 10.1139/z97-120 PG 19 WC Zoology SC Zoology GA XC870 UT WOS:A1997XC87000015 ER PT J AU Poirier, GE AF Poirier, GE TI Characterization of organosulfur molecular monolayers on Au(111) using scanning tunneling microscopy SO CHEMICAL REVIEWS LA English DT Review ID SELF-ASSEMBLED MONOLAYERS; N-ALKANETHIOLATE MONOLAYERS; PROBE MICROSCOPY; ORGANIC MONOLAYERS; SUPERLATTICE STRUCTURE; SILVER NANOSTRUCTURES; ADSORPTION-KINETICS; FORCE MICROSCOPY; THIOL MONOLAYERS; GOLD SURFACES RP Poirier, GE (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 118 TC 861 Z9 863 U1 16 U2 134 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0009-2665 J9 CHEM REV JI Chem. Rev. PD JUN PY 1997 VL 97 IS 4 BP 1117 EP 1127 DI 10.1021/cr960074m PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA XF530 UT WOS:A1997XF53000007 ER PT J AU Moriyama, S Kagawa, H Duan, CM Dickhoff, WW Plisetskaya, EM AF Moriyama, S Kagawa, H Duan, CM Dickhoff, WW Plisetskaya, EM TI Characterization of two forms of recombinant salmon insulin-like growth factor-I: Activities and complexing with insulin like growth factor-I binding proteins SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY LA English DT Article DE biological/immunological activities; IGFBP; RIA; rsIGF-I; sulfation assay; salmon; Western ligand blot ID TROUT ONCORHYNCHUS-MYKISS; IGF-I; RAINBOW-TROUT; HORMONAL-REGULATION; ESCHERICHIA-COLI; EXPRESSION; FISH; IDENTIFICATION; PURIFICATION; METHIONINE AB Coho salmon insulin-like growth factor I (IGF-I) with N-terminal glycine residue ([Gly]-rsIGF-I) was derived from methionine extended recombinant salmon IGF-I ([Met]-rsIGF-I) produced in Escherichia coli according to (18). Purified [Met]-rsIGF-I was treated with methionine aminopeptidase (MAP) to remove the N-terminal Met residue and resultant [Gly]-rsIGF-I was further purified by HPLC on a reverse-phase C4 column. The partial N-terminal amino acid sequence (residues 1-25) of [Gly]-rsIGF-I was identical to that of the native salmon IGF-I. [Gly]-rsIGF-I appeared on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) as a single band with a molecular weight of 7 kDa and cross-reacted with an antibody against [Met]-rsIGF-I in immunoblot and radioimmunoassay (RIA). In the salmon IGF-I RIA, the dilution curves of [Gly]-rsIGF-I were parallel to the [Met]-rsIGF-I standard curves and the two peptides appeared to be equally potent in displacing label. At concentrations 50 and 100 ng/ml, [Gly]rsIGF-I significantly stimulated the sulfate uptake by the cultured salmon branchial cartilage in a dose-dependent manner. The stimulatory effect of [Gly]-rsIGF-I was equipment to that of [Met]-rsIGF-I. Used as probes in a Western ligand blotting, both [Gly]-rsIGF-I and [Met]-rsIGF-I were able to bind to two IGF binding proteins (IGFBPs) of 23 kDa and 28 kDa from salmon hepatocyte culture medium. The binding could be prevented by preincubation with either unlabeled [Gly]-or [Met]-rsIGF-I. These results indicate that [Gly]-rsIGF-I, which is identical to the native form of IGF-I, and the Met-extended form of recombinant salmon IGF-I, are equally biologically and immunologically active and may substitute for each other in physiological experiments. (C) 1997 Elsevier Science Inc. C1 NATL RES INST AQUACULTURE, NANSEI, MIE 51601, JAPAN. UNIV MICHIGAN, DEPT BIOL, ANN ARBOR, MI 48109 USA. NOAA, NATL MARINE FISHERIES SERV, NW FISHERIES SCI CTR, SEATTLE, WA 98112 USA. UNIV WASHINGTON, SCH FISHERIES, SEATTLE, WA 98195 USA. RP Moriyama, S (reprint author), KITASATO UNIV, SCH FISHERIES SCI, MOL ENDOCRINOL LAB, SANRIKU, IWATE 02201, JAPAN. NR 30 TC 9 Z9 10 U1 1 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1532-0456 J9 COMP BIOCHEM PHYS C JI Comp. Biochem. Physiol. C-Toxicol. Pharmacol. PD JUN PY 1997 VL 117 IS 2 BP 201 EP 206 DI 10.1016/S0742-8413(96)00232-0 PG 6 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology SC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology GA XC743 UT WOS:A1997XC74300012 ER PT J AU Sullivan, J AF Sullivan, J TI SQL test suite goes online SO COMPUTER LA English DT Article RP Sullivan, J (reprint author), NIST,INFORMAT TECHNOL LAB,SOFTWARE DIAGNOST & CONFORMANCE TESTING DIV,GAITHERSBURG,MD 20899, USA. NR 0 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 90720-1314 SN 0018-9162 J9 COMPUTER JI Computer PD JUN PY 1997 VL 30 IS 6 BP 103 EP & DI 10.1109/2.587557 PG 2 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA XB741 UT WOS:A1997XB74100022 ER PT J AU Sadek, F Mohraz, B Taylor, AW Chung, RM AF Sadek, F Mohraz, B Taylor, AW Chung, RM TI A method of estimating the parameters of tuned mass dampers for seismic applications SO EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS LA English DT Article DE building technology; energy dissipation; passive control; seismic design; tall buildings; tuned mass dampers ID RESONANT APPENDAGES; BUILDINGS AB The optimum parameters of tuned mass dampers (TMD) that result in considerable reduction in the response of structures to seismic loading are presented. The criterion used to obtain the optimum parameters is to select, for a given mass ratio, the frequency (tuning) and damping ratios that would result in equal and large modal damping in the first two modes of vibration. The parameters are used to compute the response of several single and multi-degree-of-freedom structures with TMDs to different earthquake excitations. The results indicate that the use of the proposed parameters reduces the displacement and acceleration responses significantly. The method can also be used in vibration control of tall buildings using the so-called 'mega-substructure configuration', where substructures serve as vibration absorbers for the main structure. It is shown that by selecting the optimum TMD parameters as proposed in this paper, significant reduction in the response of tall buildings can be achieved. (C) 1997 by John Wiley & Sons, Ltd. C1 NIST,BLDG & FIRE RES LAB,STRUCT DIV,GAITHERSBURG,MD 20899. SO METHODIST UNIV,DEPT MECH ENGN,DALLAS,TX 75275. NIST,FIRE RES LAB,GAITHERSBURG,MD 20899. NR 21 TC 145 Z9 161 U1 10 U2 41 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0098-8847 J9 EARTHQUAKE ENG STRUC JI Earthq. Eng. Struct. Dyn. PD JUN PY 1997 VL 26 IS 6 BP 617 EP 635 DI 10.1002/(SICI)1096-9845(199706)26:6<617::AID-EQE664>3.0.CO;2-Z PG 19 WC Engineering, Civil; Engineering, Geological SC Engineering GA XD331 UT WOS:A1997XD33100002 ER PT J AU Gould, P Ostrom, P Walker, W AF Gould, P Ostrom, P Walker, W TI Food of flesh-tooted shearwaters Puffinus carneipes associated with high-seas driftnets in the central North Pacific Ocean SO EMU LA English DT Article ID CARBON ISOTOPES; STABLE ISOTOPES; DIET; FRACTIONATION; NITROGEN; TURNOVER; ANIMALS; TISSUES AB We examined digestive tract contents and stable nitrogen isotope ratios in breast muscles of Flesh-footed Shearwaters Puffinus carneipes associated with high-seas driftnet fisheries in the central North Pacific Ocean. Small fish, Lanternfish (Myctophidae) and Pacific Saury Cololabis saira, were the principal prey found in the digestive tracts. Pieces of unidentified fish, possibly Pacific Pomfret Brama japonica, and shredded squid tissue, mostly Neon Flying Squid Ommastrephes bartrami, in the digestive tracts indicate scavenging at driftnet fishing operations. Although soft-bodied animals such as Velella sp. were rare in the digestive tracts, low stable nitrogen isotope values (delta(15)N) suggest Flesh-footed Shearwaters feed heavily on such low trophic level animals. C1 MICHIGAN STATE UNIV, DEPT GEOL SCI, E LANSING, MI 48824 USA. NOAA, NATL MARINE FISHERIES SERV, ALASKA FISHERIES SCI CTR, NATL MARINE MAMMAL LAB, SEATTLE, WA 98115 USA. RP Gould, P (reprint author), US GEOL SURVEY, ALASKA SCI CTR, BIOL RESOURCES DIV, 1011 E TUDOR RD, ANCHORAGE, AK 99503 USA. NR 25 TC 8 Z9 8 U1 0 U2 4 PU CSIRO PUBLISHING PI CLAYTON PA UNIPARK, BLDG 1, LEVEL 1, 195 WELLINGTON RD, LOCKED BAG 10, CLAYTON, VIC 3168, AUSTRALIA SN 0158-4197 EI 1448-5540 J9 EMU JI Emu PD JUN PY 1997 VL 97 BP 168 EP 173 DI 10.1071/MU97020 PN 2 PG 6 WC Ornithology SC Zoology GA XT914 UT WOS:A1997XT91400008 ER PT J AU Checkley, DM Ortner, PB Settle, LR Cummings, SR AF Checkley, DM Ortner, PB Settle, LR Cummings, SR TI A continuous, underway fish egg sampler SO FISHERIES OCEANOGRAPHY LA English DT Article DE pelagic fish eggs; sampling; spawning; Brevoortia tyrannus; Engraulis mordax; Sardinops sagax; Gulf Stream; optical plankton counter ID ZOOPLANKTON; SYSTEM; GULF; PUMP AB We describe a method to sample the highly contagious distribution of pelagic fish eggs. CUFES, the continuous, underway fish egg sampler, consists of a submersible pump, concentrator, electronics and sample collector. This system operates continuously and under nearly all sea conditions, providing a real-time estimate of the volumetric abundance of pelagic fish eggs at pump depth, usually 3 m. CUFES-derived estimates of volumetric abundance agree well with those from nets towed at pump depth and with areal abundance estimated from vertically integrated plankton tows. CUFES has been used successfully to sample the eggs of menhaden, pinfish, sardine, and anchovy off the coasts of the eastern and western United States and South Africa. Two large patches of eggs of the Atlantic menhaden were sampled off North Carolina in winter 1993-94, had a linear scale of 5-10 km, and were found in waters between the Gulf Stream and mid-shelf front. Spawning location may he related to bathymetry. CUFES is now being used to estimate spawner biomass by the daily egg production method. An optical plankton counter provided accurate estimates of the number of Atlantic menhaden eggs sample by CUFES. C1 NOAA,ATLANTIC OCEANOG & METEOROL LAB,MIAMI,FL 33176. NOAA,BEAUFORT LAB,NATL MARINE FISHERIES SERV,BEAUFORT,NC 28518. RP Checkley, DM (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,MARINE LIFE RES GRP,LA JOLLA,CA 92093, USA. NR 33 TC 87 Z9 90 U1 1 U2 9 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD JUN PY 1997 VL 6 IS 2 BP 58 EP 73 DI 10.1046/j.1365-2419.1997.00030.x PG 16 WC Fisheries; Oceanography SC Fisheries; Oceanography GA XP856 UT WOS:A1997XP85600002 ER PT J AU Manooch, CS Potts, JC AF Manooch, CS Potts, JC TI Age, growth and mortality of greater amberjack from the southeastern United States SO FISHERIES RESEARCH LA English DT Article DE age and growth; greater amberjack; southeastern United States AB Rings on 323 sectioned otoliths (sagittae) were used to determine the ages of greater amberjack, Seriola dumerili, sampled from headboats and commercial handline vessels operating out of ports from North Carolina through the Florida Keys. Age and growth determinations were difficult. Rings were identified and counted on 71% of the samples, but measurements could be made on only 48%. The oldest fish examined was 17 years old and was 1552 mm total length (TL). Back-calculated mean lengths at annulus formation were 366, 873, 1207 and 1471 mm TL for ages 1, 5, 10 and 15, respectively. The von Bertalanffy equation describing theoretical growth for TL was L-t = 1648(1 - e(-0.119(t + 1.230))), where t = years. The equation using fork lengths (FL) was L-t = 1514(1 - e(-0.115(t + 1.178)). The weight-length relationship for greater amberjack was W = 7.2 X 10(-8)L(2.700), where W is the whole fish weight (in kg), and L is the total length (in mm). Conversion of total length to fork length may be obtained using the equation: FL = -4.807 + 0.887(TL), and fork length to total length: TL = 20.110 + 1.111(FL). Greater amberjack are fully recruited to the fishery by age 8. Estimates of total instantaneous mortality (Z) ranged from 0.60 to 0.65 depending on the year. (C) 1997 Elsevier Science B.V. RP Manooch, CS (reprint author), NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES CTR,101 PIVERS ISL RD,BEAUFORT,NC 28516, USA. NR 12 TC 12 Z9 13 U1 2 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD JUN PY 1997 VL 30 IS 3 BP 229 EP 240 DI 10.1016/S0165-7836(96)00554-1 PG 12 WC Fisheries SC Fisheries GA XF531 UT WOS:A1997XF53100005 ER PT J AU Donais, MK Saraswati, R Mackey, E Demiralp, R Porter, B Vangel, M Levenson, M Mandic, V Azemard, S Horvat, M May, K Emons, H Wise, S AF Donais, MK Saraswati, R Mackey, E Demiralp, R Porter, B Vangel, M Levenson, M Mandic, V Azemard, S Horvat, M May, K Emons, H Wise, S TI Certification of three mussel tissue standard reference materials (SRM) for methylmercury and total mercury content SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article ID METHYL MERCURY; SAMPLES AB SRM 1974a, Organics in Mussel Tissue (Mytilus edulis); SRM 2974, Organics in Mussel Tissue (freeze-dried); and SRM 2976, Mussel Tissue (trace elements and methylmercury) have been recently certified for methylmercury and total mercury content. Three independent analytical procedures were used to determine the certified methylmercury concentrations. Four independent procedures combined with data from two intercomparison exercises were used to determine the certified total mercury concentrations. These materials are the first certified metal speciation environmental SRMs issued by the National Institute of Standards and Technology. C1 NIST,STAT ENGN DIV,GAITHERSBURG,MD 20899. INT ATOM ENERGY AGCY,MARINE ENVIRONM LAB,MC-98012 MONACO,MONACO. INST APPL PHYS CHEM,RES CTR JULICH,D-52425 JULICH,GERMANY. RP Donais, MK (reprint author), NIST,DIV ANALYT CHEM,GAITHERSBURG,MD 20899, USA. NR 15 TC 25 Z9 25 U1 0 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD JUN PY 1997 VL 358 IS 3 BP 424 EP 430 DI 10.1007/s002160050441 PG 7 WC Chemistry, Analytical SC Chemistry GA XF901 UT WOS:A1997XF90100012 ER PT J AU Schantz, MM Demiralp, R Greenberg, RR Hays, MJ Parris, RM Porter, BJ Poster, DL Sander, LC Sharpless, KS Wise, SA Schiller, SB AF Schantz, MM Demiralp, R Greenberg, RR Hays, MJ Parris, RM Porter, BJ Poster, DL Sander, LC Sharpless, KS Wise, SA Schiller, SB TI Certification of a frozen mussel tissue standard reference material (SRM 1974a) for trace organic constituents SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; NEW-BEDFORD HARBOR; POLYCHLORINATED-BIPHENYLS; MARINE SEDIMENT; MYTILUS-EDULIS; LAKE-SUPERIOR; FOOD-CHAINS; BIOACCUMULATION; CONTAMINANTS; ENVIRONMENT AB NIST SRM 1974a, Organics in Mussel Tissue (Mytilus edulis), has been issued as a frozen tissue homogenate with certified mass fractions for 15 polycyclic aromatic hydrocarbons (PAHs), 20 polychlorinated biphenyl (PCB) congeners, and 7 chlorinated pesticides. Noncertified mass fractions are provided for an additional 18 PAHs, 4 PCB congeners, 4 chlorinated pesticides, 28 inorganic constituents, 16 aliphatic hydrocarbons, and methylmercury. The mass fractions for the measured PAHs range from approximately 1 mu g/kg to 164 mu g/kg dry mass while the mass fractions for the measured PCB congeners range from approximately 3 mu g/kg to 150 mu g/kg dry mass. C1 NIST,STAT ENGN DIV,GAITHERSBURG,MD 20899. RP Schantz, MM (reprint author), NIST,DIV ANALYT CHEM,GAITHERSBURG,MD 20899, USA. OI Sharpless, Katherine/0000-0001-6569-198X NR 32 TC 33 Z9 33 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD JUN PY 1997 VL 358 IS 3 BP 431 EP 440 DI 10.1007/s002160050442 PG 10 WC Chemistry, Analytical SC Chemistry GA XF901 UT WOS:A1997XF90100013 ER PT J AU vanDam, TM Wahr, J Chao, Y Leuliette, E AF vanDam, TM Wahr, J Chao, Y Leuliette, E TI Predictions of crustal deformation and of geoid and sea-level variability caused by oceanic and atmospheric loading SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE geoid; global positioning system; gravity; oceans ID SATELLITE ALTIMETRY; TEMPORAL VARIATIONS AB In this paper we consider several small effects related to oceanic loading of the Earth and atmospheric loading of the oceans. Non-tidal ocean loading induces changes in oceanic bottom pressure, which in turn deform the geoid and the nearby crust. Changes in bottom pressure are derived from estimates of sea-surface height variability and density changes output from an oceanic general circulation model. Sea-surface heights measured by the TOPEX/POSEIDON altimeter are also used to infer changes in bottom pressure. We estimate that non-tidal ocean loading can typically cause approximate to 5 mm of peak-to-peak (2 mm root-mean-square, rms) vertical motion at sites near the shore, with displacements of up to 10 mm possible. Amplitudes of horizontal displacements are about one-third those of vertical ones. Deformation-associated gravity changes are usually of the order of 2-3 mu Gal; however, peak-to-peak changes of 5 mu Gal are also predicted. Loading-induced geoid perturbations in mid-ocean regions are typically 5-10 mm peak-to-peak (3 mm rms) and can extend over a region of 20 degrees. In the case of atmospheric loading of the oceans, we estimate the difference between the inverted barometer correction, usually used to describe the ocean's response to atmospheric pressure, and the complete equilibrium response. There are two sources of this difference. One is that the inverted barometer correction does not conserve oceanic mass. We use National Meteorological Center (NMC) global pressure data to estimate the time-dependent, average change in pressure over the oceans. A time-series of the net pressure over the oceans contains an annual signal with a peak-to-peak amplitude of 1.2 mbar superimposed on a linear trend of 0.09 mbar yr(-1). The secular signal is caused by a redistribution of atmospheric mass from over continental land masses to the oceans. We conclude that this effect introduces additional variability into the ocean's response to pressure at annual, secular, and multi-year timescales, with a total peak-to-peak amplitude of a few tens of millimetres. The second difference between the inverted barometer response and the complete equilibrium response is due to gravitational forcing by the atmosphere and by the displaced mass in the solid Earth and oceans caused by the atmospheric loading. This effect is largest within about 1000 km of the coast and at high latitudes. We use NMC pressure data to estimate the effect, and rind that it causes differences from the inverted barometer solution in those regions of up to 10-30 mm peak-to-peak, with values as large as 50-60 mm possible at certain locations. The time dependence of this effect is negatively correlated with the inverted barometer response. The effect causes an apparent reduction of the inverted barometer response by a few per cent within a few hundred kilometres of the coast, with reductions of more than 6-7 per cent at a few places. C1 UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. CALTECH,JET PROP LAB,PASADENA,CA 91006. RP vanDam, TM (reprint author), UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,CAMPUS BOX 216,BOULDER,CO 80309, USA. RI Leuliette, Eric/D-1527-2010 OI Leuliette, Eric/0000-0002-3425-4039 NR 24 TC 36 Z9 37 U1 3 U2 5 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD JUN PY 1997 VL 129 IS 3 BP 507 EP 517 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XC862 UT WOS:A1997XC86200004 ER PT J AU Titov, VV Synolakis, CE AF Titov, VV Synolakis, CE TI Extreme inundation flows during the Hokkaido-Nansei-Oki tsunami SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RUN-UP; EARTHQUAKE TSUNAMI; CIRCULAR ISLAND; FIELD SURVEY AB The tsunami generated by the July 12, 1993 Hokkaido-Nansei-Oki M-w = 7.8 earthquake produced in Japan the worst local tsunami-related death toll in fifty years, with estimated 10-18m/sec overland flow velocities and 30m runup. These extreme values are the largest recorded in Japan this century and are among the highest ever documented for non-landslide generated tsunamis. We model this event to confirm the estimated overland flow velocities, and we find that, given reasonable ground deformation data, current state-of-the-art shallow-water wave models can predict tsunami inundation correctly including extreme runup, current velocities and overland flow. We find that even small local topographic structures affect the runup to first-order, and that the resolution of the bathymetric data is more important than the grid resolution. Our results qualitatively suggest that for this event-coastal inundation is more correlated with inundation velocities than with inundation heights, explaining also why threshold-type modeling has substantially underpredicted coastal inundation for this and other recent events. C1 UNIV SO CALIF,LOS ANGELES,CA 90089. RP Titov, VV (reprint author), NOAA,PACIFIC MARINE ENVIRONM LAB,7600 SAND POINT WAY NE,SEATTLE,WA 98115, USA. RI Synolakis, Costas/B-3197-2008; OI Synolakis, Costas/0000-0003-0140-5379; Titov, Vasily/0000-0002-1630-3829 NR 30 TC 88 Z9 91 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1997 VL 24 IS 11 BP 1315 EP 1318 DI 10.1029/97GL01128 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XD217 UT WOS:A1997XD21700009 ER PT J AU Haywood, JM Stouffer, RJ Wetherald, RT Manabe, S Ramaswamy, V AF Haywood, JM Stouffer, RJ Wetherald, RT Manabe, S Ramaswamy, V TI Transient response of a coupled model to estimated changes in greenhouse gas and sulfate concentrations. SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN ATMOSPHERE MODEL; GRADUAL CHANGES; AEROSOLS; CO2 AB This study investigates changes in surface air temperature (SAT), hydrology and the thermohaline circulation due to the the radiative forcing of anthropogenic greenhouse gases and the direct radiative forcing (DRF) of sulfate aerosols in the GFDL coupled ocean-atmosphere model. Three 300-year model integrations are performed with increasing greenhouse gas concentrations only, increasing sulfate aerosol concentrations only and increasing greenhouse gas and sulfate aerosol concentrations. A control integration is also performed keeping concentrations of sulfate and carbon dioxide fixed. The global annual mean SAT change when both greenhouse gases and sulfate aerosols are included is in better agreement with observations than when greenhouse gases alone are included. When the global annual mean SAT change from a model integration that includes only increases in greenhouse gases is added to that from a model integration that includes only increases in sulfate, the resulting global SAT change is approximately equal to that from a model integration that includes increases in both greenhouse gases and sulfate aerosol throughout the integration period. Similar results are found for global annual mean precipitation changes and for the geographical distribution of both SAT and precipitation changes indicating that the climate response is linearly additive for the two types of forcing considered here. Changes in the mid-continental summer dryness and thermohaline circulation are also briefly discussed. C1 PRINCETON UNIV,GEOPHYS FLUID DYNAM LAB,PRINCETON,NJ 08542. RP Haywood, JM (reprint author), PRINCETON UNIV,AOS PROGRAM,PRINCETON,NJ 08542, USA. NR 15 TC 110 Z9 124 U1 2 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1997 VL 24 IS 11 BP 1335 EP 1338 DI 10.1029/97GL01163 PG 4 WC Geosciences, Multidisciplinary SC Geology GA XD217 UT WOS:A1997XD21700014 ER PT J AU Gruber, N Sarmiento, JL AF Gruber, N Sarmiento, JL TI Global patterns of marine nitrogen fixation and denitrification SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Review ID OXYGEN-DEFICIENT CONDITIONS; TROPICAL NORTH-PACIFIC; SARGASSO SEA; ARABIAN SEA; NUTRIENT REGENERATION; ATMOSPHERIC NITROGEN; POTENTIAL TEMPERATURE; ATLANTIC THERMOCLINE; ISOPYCNAL SURFACES; MEDITERRANEAN-SEA AB A new quasi-conservative tracer N*, defined as a linear combination of nitrate and phosphate: is proposed to investigate the distribution of nitrogen fixation and denitrification in the world oceans. Spatial patterns of N* are determined in the different ocean basins using data from the Geochemical Ocean Sections Study (GEOSECS) cruises (1972-1978) and from eight additional cruises in the Atlantic Ocean. N* is low (< -3 mu mol kg(-1)) in the Arabian Sea and in the eastern tropical North and South Pacific. This distribution is consistent with direct observations of water column denitrification in these oxygen minimum zones. Low N* concentrations in the Bering Sea and near the continental shelves of the east and west coasts of North America also indicate a sink of N* due to benthic denitrification. High concentrations of N* (>2.0 mu mol kg(-1)) indicative of prevailing: nitrogen fixation are found in the thermocline of the tropical and subtropical North Atlantic and in the Mediterranean. This suggests that on a global scale these basins are acting as sources of fixed nitrogen: while the Indian Ocean and parts of the Pacific Ocean are acting as sinks. Nitrogen fixation is estimated in the North Atlantic Ocean (10 degrees N-50 degrees N) using the N* distribution along isopycnal surfaces and information about the water age. We calculate a fixation rate of 28 Tg N yr(-1) which is about 3 times larger than the most recent global estimate. Our result is in line, however: with some recent suggestions that pelagic nitrogen fixation may be seriously underestimated. The implied flux of 0.072 mol N m(-2) yr(-1) is sufficient to meet all the nitrogen requirement of the estimated net community production in the mixed layer during summer at the Bermuda Atlantic Time-ser ies Study (BATS) site in the northwestern Sargasso Sea. Extrapolation of our North Atlantic estimate to the global ocean suggests that the present-day budget of nitrogen in the ocean may be in approximate balance. C1 PRINCETON UNIV, ATMOSPHER & OCEAN SCI PROGRAM, PRINCETON, NJ 08544 USA. RP Gruber, N (reprint author), UNIV BERN, INST PHYS, SIDLERSTR 5, CH-3012 BERN, SWITZERLAND. RI Gruber, Nicolas/B-7013-2009 OI Gruber, Nicolas/0000-0002-2085-2310 NR 125 TC 686 Z9 709 U1 23 U2 213 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUN PY 1997 VL 11 IS 2 BP 235 EP 266 DI 10.1029/97GB00077 PG 32 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA XP160 UT WOS:A1997XP16000007 ER PT J AU Abend, AG Smith, TD AF Abend, AG Smith, TD TI Differences in stable isotope ratios of carbon and nitrogen between long-finned pilot whales (Globicephala melas) and their primary prey in the western north Atlantic SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT Mini-Symposium on Arctic Oceanographic Processes - 1995, at the 1995 ICES Annual Science Conference CY 1995 CL AALBORG, DENMARK SP Int Council Explorat Sea DE pilot whale; stable isotope; diet; mackerel; squid; trophic level ID FOOD-WEB STRUCTURE; DIET; FRACTIONATION; ANIMALS AB Carbon (C-13/C-12) and nitrogen (N-15/N-14) stable isotope ratios were measured in skin and muscle samples from free-ranging long-finned pilot whales stranded or caught in fishing gear in two locations in the western north Atlantic. Samples of the principal pilot whale prey species, long-finned squid and a secondarily important species, Atlantic mackerel, were collected for stable isotope analysis from three areas in the western north Atlantic. The stable carbon and nitrogen ratios from the mackerel and squid samples did not differ between areas. However, carbon ratios differed between the two prey species, while the nitrogen ratios did not. The difference between the stable nitrogen isotope ratios for prey and predator suggests trophic enrichment of 1.1 to 1.7 parts per thousand, values substantially lower than previously assumed for cetaceans. The differences between carbon ratios among prey species and whale tissues suggest that mackerel comprise a significant proportion of the diet of pilot whales. (C) 1997 International Council for the Exploration of the Sea. C1 UNIV MASSACHUSETTS,DEPT FORESTRY & WILDLIFE MANAGEMENT,AMHERST,MA. NE FISHERIES SCI CTR,WOODS HOLE,MA 02543. NR 14 TC 28 Z9 28 U1 0 U2 6 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD JUN PY 1997 VL 54 IS 3 BP 500 EP 503 DI 10.1006/jmsc.1996.0192 PG 4 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA XG981 UT WOS:A1997XG98100019 ER PT J AU Mechels, SE Schlager, JB Franzen, DL AF Mechels, SE Schlager, JB Franzen, DL TI High-resolution differential-mode delay measurements in optical fibers using a frequency-domain phase-shift technique SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE optical fiber communication; optical fiber dispersion; optical fiber measurements; optical fibers; optical fiber testing AB A frequency-domain phase-shift technique, with a temporal resolution of 0.2 ps, is used to obtain differential mode delay measurements in graded-index multimode fibers. This resolution is a significant improvement over previously reported time-domain methods. As a consequence, useful results can be obtained from fibers as short as 15 m. Measurements performed at 850 nm, on 62.5-mu m core diameter fibers from several different manufacturers, indicate a rich variety of mode delay profiles. Measurements on lengths ranging from 3 to 500 m, indicate that delay profiles are established in the first few meters of fiber, and the general characteristics are retained over long distances. RP Mechels, SE (reprint author), NATL INST STAND & TECHNOL,DIV OPTOELECT,325 BROADWAY,BOULDER,CO 80303, USA. NR 6 TC 8 Z9 9 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD JUN PY 1997 VL 9 IS 6 BP 794 EP 796 DI 10.1109/68.584993 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA XA049 UT WOS:A1997XA04900028 ER PT J AU Proctor, FM Albus, JS AF Proctor, FM Albus, JS TI Open-architecture controllers SO IEEE SPECTRUM LA English DT Article C1 NATL INST STAND & TECHNOL,INTELLIGENT SYST DIV,GAITHERSBURG,MD 20899. RP Proctor, FM (reprint author), NATL INST STAND & TECHNOL,CONTROL GRP,GAITHERSBURG,MD 20899, USA. NR 4 TC 11 Z9 13 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9235 J9 IEEE SPECTRUM JI IEEE Spectr. PD JUN PY 1997 VL 34 IS 6 BP 60 EP 64 DI 10.1109/6.591666 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA XB595 UT WOS:A1997XB59500022 ER PT J AU Bray, SL Ekin, JW Sesselmann, R AF Bray, SL Ekin, JW Sesselmann, R TI Tensile measurements of the modulus of elasticity of Nb3Sn at room temperature and 4 K SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID STRESS AB The critical current of Nb,Sn superconductors is highly sensitive to strain, Consequently, accurate mechanical modeling of these conductors is necessary to interpret experimental data and to predict conductor performance in applications such as large magnet systems, A key parameter in these models is the modulus of elasticity (E, Young's modulus); however, there are large discrepancies in the available data, and there are no published tensile-test data on E for Nb3Sn. Tensile test specimens were prepared from a starting material of Nb tape with 1.4 wt.% ZrO2 precipitates. Tensile measurements of unreacted Nb and partially reacted Nb-Nb3Sn tapes were made at room temperature (293 K) and at 4 K. A modulus of elasticity of 65 +/- 15 GPa was extrapolated from these measurements for polycrystalline Nb3Sn at 4 K, and 150 +/- 15 GPa at room temperature. C1 UNIV COLORADO,BOULDER,CO 80309. RP Bray, SL (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO, USA. NR 20 TC 9 Z9 9 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 1451 EP 1454 DI 10.1109/77.620845 PN 2 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH866 UT WOS:A1997XH86600084 ER PT J AU Goodrich, LF Medina, LT Stauffer, TC AF Goodrich, LF Medina, LT Stauffer, TC TI Repeatability of critical-current measurements on Nb3Sn and Nb-Ti wires SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA AB A varying degree of repeatability has been observed in critical-current (I-c) measurements of Nb3Sn and Nb-Ti wires as a function of the number of thermal cycles from room temperature to 4 K. The increase of I-c between the first and second thermal cycle can be 1% to 2% at 12 T for Nb3Sn wires. This was observed on a Nb3Sn wire by all four laboratories that participated in a recent interlaboratory comparison conducted in the International Thermonuclear Experimental Reactor (ITER) project. These data indicate that if I-c changes beyond the error limits, it increases fairly monotonically with thermal cycling until it eventually saturates. In contrast, the I-c of a Nb-Ti wire is very repeatable with thermal cycling. This suggests that the effect on the Nb3Sn wire is due to its strain sensitivity. Most of these data were taken with the sample on a Ti-6Al-4V measurement mandrel This study also investigated the repeatability of I-c measurements using other mandrel materials. The increase in I-c of Nb3Sn wire could enhance the performance of some applications. However, the lack of repeatability in I-c measurements on Nb3Sn wires is a limitation in precise interlaboratory comparisons. RP Goodrich, LF (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO, USA. NR 5 TC 3 Z9 3 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 1508 EP 1511 DI 10.1109/77.620859 PN 2 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH866 UT WOS:A1997XH86600098 ER PT J AU Ma, ZX deObaldia, E Hampel, G Polakos, P Mankiewich, P Batlogg, B Prusseit, W Kinder, H Anderson, A Oates, DE Ono, R Beall, J AF Ma, ZX deObaldia, E Hampel, G Polakos, P Mankiewich, P Batlogg, B Prusseit, W Kinder, H Anderson, A Oates, DE Ono, R Beall, J TI RF power dependence study of large area YBCO thin films SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID RESONATORS AB In an effort to develop HTS superconducting filters with sufficient power handling capability for PCS (Personal Communication Services) base station transmit applications, we have undertaken a study of the power dependence of large area YBCO thin films on LaAlO3 substrates, We employed a coplanar-wave-guide (CPW) resonator technique to obtain the changes of loss and inductance versus circulating microwave currents in the films. Data have been collected on uniform large area (2'' diameter) films grown by coevaporation and off-axis sputtering techniques under varying deposition conditions, We found correlations between the RF power dependence and other film properties such as penetration depth and crystal structure. The most intrinsic sample, from the coevaporation technique, characterized by the smallest penetration depth, good orthorhombicity and absence of tetragonal phase, shows the least amount of nonlinearity. Such correlations can be used to prescreen films for fabrication and monitor the film production line, However, films from coevaporation and off-axis sputtering show very distinct power dependent behaviors. C1 TECH UNIV MUNICH,D-8046 GARCHING,GERMANY. MIT,LINCOLN LAB,LEXINGTON,MA 02173. NIST,BOULDER,CO. RP Ma, ZX (reprint author), AT&T BELL LABS,LUCENT TECHNOL,700 MT AVE,MURRAY HILL,NJ 07974, USA. NR 16 TC 21 Z9 21 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 1911 EP 1916 DI 10.1109/77.620959 PN 2 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH866 UT WOS:A1997XH86600197 ER PT J AU Stork, FJB Beall, JA Roshko, A DeGroot, DC Rudman, DA Ono, RH Krupka, J AF Stork, FJB Beall, JA Roshko, A DeGroot, DC Rudman, DA Ono, RH Krupka, J TI Surface resistance and morphology of YBCO films as a function of thickness SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID SCANNING TUNNELING MICROSCOPY; YBA2CU3O7 THIN-FILMS; TOPOGRAPHY AB We have examined the thickness dependence of the growth morphology and surface resistance R-s of laser ablated YBa2Cu3O7-x films with transition temperatures over 89 K and critical current densities greater than 10(6) A/cm(2) at 76 K. The thickness was varied from 50 to 1600 nm while all other deposition conditions were maintained constant. The microstructure has been characterized by scanning electron microscopy and scanning tunneling microscopy (STM). The films exhibit two-dimensional island growth at all thicknesses and the island density continuously decreased with film thickness as a power law with an exponent of -0.5. The surface resistance was measured at 76 K with a dielectric rod resonator. for films less than 300 nm thick, the fields penetrated the superconducting films, causing a rapid increase in the apparent R-s with decreasing film thickness. Films thicker than 800 nm showed microcracks and the R-s increased sharply, and no resonance was observed above 1000 nm. C1 WARSAW UNIV TECHNOL,WARSAW,POLAND. RP Stork, FJB (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 15 TC 20 Z9 20 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 1921 EP 1924 DI 10.1109/77.620961 PN 2 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH866 UT WOS:A1997XH86600199 ER PT J AU Li, HQ Ono, RH Vale, LR Rudman, DA Liou, SH Mallison, WH AF Li, HQ Ono, RH Vale, LR Rudman, DA Liou, SH Mallison, WH TI An improved multi-layer fabrication process for YBa2Cu3O7-x-based circuits SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID FILM FLUX TRANSFORMERS; NOISE AB Improved via connections in structures of YBa2Cu3O7-x/SrTiO3/YBa2Cu3O7-x (YBCO/STO/YBCO) multilayers have been made using a combined HF wet-etching and ion-milling process. The critical current density J(C) of the via is as high as 2 x 10(6) A/cm(2) at 76 K, and is dominated by edge contacts in the ab-plane. YBCO and Sr2AlNbO6 (SAN) multilayer test circuits were also made with this process. The 4 degrees crossovers in a SAN test chin had a critical temperature T-C of 88 K and J(C) of 1.5 x 10(6) A/cm(2) at 81 K, very close to those of the planar film, showing no evidence of weak links in the YBCO crossing low angle SAN steps. C1 CONDUCTUS INC,SUNNYVALE,CA 94086. UNIV NEBRASKA,DEPT PHYS,LINCOLN,NE 68588. RP Li, HQ (reprint author), NATL INST STAND & TECHNOL,BOULDER,CO 80303, USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2169 EP 2172 DI 10.1109/77.621023 PN 2 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH866 UT WOS:A1997XH86600260 ER PT J AU Ruggiero, ST Zhong, C Rennert, KJ Vale, LR Rudman, DA AF Ruggiero, ST Zhong, C Rennert, KJ Vale, LR Rudman, DA TI Response of YBCO devices to mid-infrared radiation SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID THIN-FILMS; PHOTORESPONSE AB We present results oil the responsivity of YBCO thin-film devices to mid-infrared (25 mu m) radiation, Light is generated by pulsed diode-laser sources monitored by a calibrated HgCdTe detector, Par the sample geometry studied here, we estimate an upper limit to the low-frequency responsivity, R of similar to 1000 V/W. C1 GRINNELL COLL, DEPT PHYS, GRINNELL, IA 50112 USA. NATL INST STAND & TECHNOL, BOULDER, CO 80303 USA. RP UNIV NOTRE DAME, DEPT PHYS, NOTRE DAME, IN 46556 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1051-8223 EI 1558-2515 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2374 EP 2377 DI 10.1109/77.621717 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700027 ER PT J AU Benz, SP Burroughs, CJ AF Benz, SP Burroughs, CJ TI Constant-voltage steps in arrays of Nb-PdAu-Nb Josephson junctions SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID SHAPIRO STEPS AB Design and fabrication of Nb-PdAu-Nb trilayer Josephson junctions are described. The microwave response of an array of 1000 of these junctions was measured, and constant-voltage step heights were characterized as a function of the microwave amplitude and frequency. Experimental results fit well to point-junction simulations at the 3 GHz design frequency of the microwave distribution network. The observed step height of 3.8 mA shows that the array and microwave distribution are sufficiently uniform for application in programmable Josephson voltage standards. RP Benz, SP (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 10 TC 17 Z9 17 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2434 EP 2437 DI 10.1109/77.621732 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700042 ER PT J AU Hamilton, CA Benz, SP Burroughs, CJ Harvey, TE AF Hamilton, CA Benz, SP Burroughs, CJ Harvey, TE TI SNS programmable voltage standard SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID JOSEPHSON AB Superconductor-Normal-Superconductor (SNS) junctions have been used in the design and fabrication of a 1-V rapidly programmable voltage standard. The superconducting circuit is a series array of 32 768 Nb-PdAu-Nb junctions with taps that divide the array into a binary sequence of smaller array segments with a minimum segment size of 128 junctions. The 16-GHz drive frequency is set by the characteristic frequency of the junctions. A computer-controlled 8-channel bias system controls the current in each segment and allows the rapid selection of any one of 513 discrete voltage levels. The system is designed for fast dc measurements and the synthesis of precise ac waveforms. RP Hamilton, CA (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 5 TC 14 Z9 14 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2472 EP 2475 DI 10.1109/77.621740 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700050 ER PT J AU Ono, RH Koch, JA Steinbach, A Huber, ME Cromar, MW AF Ono, RH Koch, JA Steinbach, A Huber, ME Cromar, MW TI Tightly coupled dc SQUIDs with resonance damping SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA AB We have reduced the effect of resonances on washer style dc SQUIDs coupled to input flux transformers and analyzed our damping structures using a distributed circuit model, a resistance of 1 Omega is placed across each turn of a 137-turn coil coupled to a planar washer dc SQUID reducing the structure in the voltage-flux curve thus extending the range of current biases over which the device operates, The energy sensitivity of the SQUID is predicted to not be degraded by the intra-coil resistors. C1 UNIV COLORADO,DENVER,CO 80217. SUPERCONDUCTING CORE TECHNOL,GOLDEN,CO 80401. RP Ono, RH (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. RI Huber, Martin/B-3354-2011 NR 9 TC 6 Z9 6 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2538 EP 2541 DI 10.1109/77.621756 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700066 ER PT J AU Benz, SP Burroughs, CJ Hamilton, CA AF Benz, SP Burroughs, CJ Hamilton, CA TI Operating margins for a pulse-driven programmable voltage standard SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID JUNCTIONS AB We have designed and fabricated a Josephson voltage standard where the voltage can be rapidly and continuously programmed by changing the repetition frequency of a pulse drive. Simulations are made to optimize the operating margins of the circuit for different pulse waveforms. The response of a 1000-junction array of Nb-PdAu-Nb junctions is measured, and constant-voltage step heights are characterized as a function of the pulse amplitude, pulse width, and frequency. A dc bias range of 0.62 mA is demonstrated over a continuous voltage-tunable range from -6.2 mV to +6.5 mV. RP Benz, SP (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 5 TC 14 Z9 14 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2653 EP 2656 DI 10.1109/77.621784 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700094 ER PT J AU Booth, JC Beall, JA DeGroot, DC Rudman, DA Ono, RH Miller, JR Chen, ML Hong, SH Ma, QY AF Booth, JC Beall, JA DeGroot, DC Rudman, DA Ono, RH Miller, JR Chen, ML Hong, SH Ma, QY TI Microwave characterization of coplanar waveguide transmission lines fabricated by ion implantation patterning of YBa2Cu3O7-delta SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID TEMPERATURE SUPERCONDUCTING FILMS AB We report on the application of Si and Al ion-implantation patterning to the fabrication of low-loss microwave transmission lines in high-temperature superconductor (HTS) thin films, Using this technique, we have fabricated coplanar waveguide (CPW) transmission lines in YBa2Cu3O7-delta (YBCO) thin films deposited on LaAlO3 substrates. We have used both resonant and broadband measurements in order to characterize the performance of the resulting transmission line structures, For the broadband measurements, on-wafer calibrations were used to obtain accurate S-parameters and transmission line propagation constants up to 25 GHz, The propagation constants of the ion-implanted transmission lines do not differ significantly from those of lines patterned using conventional ion over the frequency range studied, with a value for the attenuation constant of approximately 0.03-0.04 dB/cm at 50 K and 10 GHz. The relatively low losses of the ion-implanted devices demonstrate the effectiveness of this method of patterning for HTS microwave device fabrication. C1 COLUMBIA UNIV,NEW YORK,NY. RP Booth, JC (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 8 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2780 EP 2783 DI 10.1109/77.621814 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700124 ER PT J AU Xu, YZ Ekin, JW Russek, SE Fiske, R Clickner, CC Takeuchi, I Trajanovic, Z Venkatesan, T Rogers, CT AF Xu, YZ Ekin, JW Russek, SE Fiske, R Clickner, CC Takeuchi, I Trajanovic, Z Venkatesan, T Rogers, CT TI a-Axis YBa2Cu3O7-delta/Au interface conductance-voltage characteristics SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID ZERO-BIAS ANOMALIES; MAGNETIC SCATTERING; JUNCTIONS; CONTACTS; RANGE AB Conductance-voltage characteristics of interfaces between a-axis YBa2Cu3O7-delta (YBCO) thin films and gold are presented. When the gold counter electrode is deposited in-situ, the junctions have a specific interface resistivity in the 10(-9) Omega-cm(2) range, about an order of magnitude lower than nominal in-situ, c-axis YBCO/noble-metal junctions. As with nominal c-axis YBCO/noble-metal junctions, there is clear evidence at T = 4 K for a peak in the conductance at low bias. In addition, a dip in the middle of the broad peak structure was resolved. It appears to be a feature unique to the a-axis YBCO/Au interface. C1 UNIV MARYLAND,CTR SUPERCONDUCT RES,COLLEGE PK,MD 20742. UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. RP Xu, YZ (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 10 TC 4 Z9 4 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2836 EP 2839 DI 10.1109/77.621870 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700137 ER PT J AU Huber, ME Cromar, MW Ono, RH AF Huber, ME Cromar, MW Ono, RH TI Excess low-frequency flux noise in dc SQUIDs SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID OXIDE/NB JOSEPHSON-JUNCTIONS AB We have fabricated dc superconducting quantum interference devices (SQUIDs) incorporating Nb/Al-oxide/Nb Josephson junctions in both stripline and washer geometries. Low-frequency noise in excess of the predicted by the resistively-shunted junction model is present in both geometries and is demonstrated to be flux noise. This flux noise is no environmental. Improvements in fabrication processing over the past four years have reduced the level of this flux noise. SQUIDs are now fabricated with PdAu resistors, Nb wiring layers, and SiO2 interlayer dielectric. In our best well-coupled SQUIDs, the white-noise energy sensitivity is 5 x 10(31) J.s, with a 1/f knee below 0.1 Hz. We believe further reduction in the flux noise might be obtained with the use of on-chip flux shielding and/or trapping structures. C1 SUPERCONDUCTING CORE TECHNOL,GOLDEN,CO 80401. NATL INST STAND & TECHNOL,BOULDER,CO 80303. RP Huber, ME (reprint author), UNIV COLORADO,DENVER,CO 80217, USA. RI Huber, Martin/B-3354-2011 NR 9 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 2882 EP 2885 DI 10.1109/77.621893 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700148 ER PT J AU McDonald, DG Phelan, RJ Vale, LR Ono, RH Rice, JP Borcherdt, L Rudman, DA Cosgrove, J Rosenthal, P AF McDonald, DG Phelan, RJ Vale, LR Ono, RH Rice, JP Borcherdt, L Rudman, DA Cosgrove, J Rosenthal, P TI Noise from YBCO films: Size and substrate dependence SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID THIN-FILMS; SILICON; SUPERCONDUCTORS; BOLOMETERS AB Electrical noise measurements at 10 Hz are reported for YBCO films at the resistive edge. Results are given for films with widths of 0.1, 1, and 5 mm that were deposited simultaneously on the same substrate, for three different substrate materials. The NET improves by approximately a factor of 10 as the thermometer area is increased by a factor of 2500, with fixed bias current. At temperatures giving maximum dR/dT and with nominally 19 mA bias currents, the 5 mm samples have very low noise equivalent temperatures of 3.1, 3.5, and 4.4 nK/root Hz for LaAlO3, Al2O3, and Si substrates, respectively. These are the lowest values reported up to the present time. Suprisingly, noise from the sample on si is consistent with pure Johnson noise even with bias current as large as 5 mA (0.28 x 10(4) A/cm(2)). For YBCO thicknesses no greater than 50 nm excellent thermometers can be made on any of these substrates in spite of the mechanical strains produced in the films by the substrate. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. ADV FUEL RES INC,E HARTFORD,CT 06138. RP McDonald, DG (reprint author), BOULDER METR INC,BOULDER,CO 80303, USA. NR 13 TC 4 Z9 4 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 3091 EP 3095 DI 10.1109/77.621986 PN 3 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700200 ER PT J AU Vale, LR Ono, RH Rudman, DA AF Vale, LR Ono, RH Rudman, DA TI YBa2Cu3O7-x Josephson junctions on bicrystal Al2O3 and SrTiO3 substrates SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID GRAIN-BOUNDARY JUNCTIONS; RESISTANCE AB Bicrystal grain-boundary junctions (bi-GBJs) have been reproducibly fabricated on SrTiO3 (STO) and r-plane Al2O3 (sapphire) bicrystal substrates. Sapphire bicrystals are candidates for high-frequency applications due to their low dielectric constant and loss tangent. The sapphire bi-GBJs demonstrated resistively shunted junction (RSJ)-like current voltage characteristics, with junction parameters comparable to the STO bi-GBJs and critical current densities J(c) similar to 10(5) A/cm(2). Independent control of junction resistance (R-N) was demonstrated with the used of Au shunt layers. In addition, overlayers such as Au or STO may act to passivate the GBJs and improve long term stability. RP Vale, LR (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 13 TC 30 Z9 30 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 3193 EP 3196 DI 10.1109/77.622009 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700223 ER PT J AU Kunkel, G Hechtfischer, G Frommberger, M Veit, K Kleiner, R Muller, P Prusseit, W Kinder, H Ferchland, L Daalmans, G Ono, RH AF Kunkel, G Hechtfischer, G Frommberger, M Veit, K Kleiner, R Muller, P Prusseit, W Kinder, H Ferchland, L Daalmans, G Ono, RH TI Millimeter-wave radiation in high-T-c Josephson junctions SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA AB We have investigated millimeter-wave radiation from single Josephson junctions and small phase-locked Josephson junction arrays. Josephson junctions were fabricated on sapphire bicrystal substrates. Emission could be measured up to 110 GHz. Resonances in ten-junction circuits yield linewidths narrower than 200 MHz. This type of array might be useful for applications in integrated receiver systems. C1 TECH UNIV MUNICH, PHYS DEPT E10, D-85747 GARCHING, GERMANY. SIEMENS CO, RES & DEV, ERLANGEN, GERMANY. NATL INST STAND & TECHNOL, DIV ELECTROMAGNET TECHNOL, BOULDER, CO 80303 USA. RP UNIV ERLANGEN NURNBERG, ERWIN ROMMEL STR 1, D-91058 ERLANGEN, GERMANY. RI Muller, Paul/H-2179-2013 NR 6 TC 11 Z9 11 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1051-8223 EI 1558-2515 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 3339 EP 3342 DI 10.1109/77.622080 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700259 ER PT J AU Young, BA Nam, SW Brink, PL Cabrera, B Chugg, B Clarke, RM Davies, AK Irwin, KD AF Young, BA Nam, SW Brink, PL Cabrera, B Chugg, B Clarke, RM Davies, AK Irwin, KD TI Technique for fabricating tungsten thin film sensors with T-c <=100 mK on germanium and silicon substrates SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID PARTICLE-DETECTION AB Until recently, our work on superconducting thin film phonon sensors for cryogenic detector applications was limited to silicon substrates only. We have now successfully extended low T-c (less than or equal to 100 mK) tungsten sensor technology and sensor fabrication capability to include high purity substrates as well. Here, we describe a technique for fabricating low T-c superconducting tungsten films on germanium, and we present first results from cryogenic characterization experiments with these films. We also summarize our work on the development of a process to independently etch aluminum and tungsten films deposited on the same germanium substrate, The capability to selectively etch aluminum and tungsten films is critical for the fabrication of our silicon and soon also germanium detectors which utilize overlapping thin films of superconducting tungsten and aluminum for the phonon sensors. C1 SANTA CLARA UNIV,DEPT PHYS,SANTA CLARA,CA 95053. NATL INST STAND & TECHNOL,BOULDER,CO 80303. RP Young, BA (reprint author), STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305, USA. NR 11 TC 6 Z9 6 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 3367 EP 3370 DI 10.1109/77.622094 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700266 ER PT J AU Hamilton, CA Burroughs, CJ Benz, SP AF Hamilton, CA Burroughs, CJ Benz, SP TI Josephson voltage standard - A review SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1996 Applied Superconductivity Conference CY AUG 25-30, 1996 CL PITTSBURGH, PA ID SERIES-ARRAY; JUNCTIONS; ACCURACY AB The unique ability of a Josephson junction to convert a microwave frequency f into a voltage Nhf/2e with high accuracy and the adoption of this phenomenon as the basis for the SI Volt Realization have created a market for Josephson voltage standards that is unassailable from any other technology. This paper reviews the development of Josephson voltage standards including the junction and array design, the microwave circuit, and the system integration, With the dr Josephson standard largely transferred to the commercial sector, NIST is developing a new class of devices in which the output voltage can be rapidly programmed either by digitally selecting the quantum number N or by driving the Josephson array with a variable frequency pulse train. These new devices will make possible fret, high-accuracy characterizations of A/D and D/A converters and the synthesis of ac waveforms. RP Hamilton, CA (reprint author), NATL INST STAND & TECHNOL, 325 BROADWAY, BOULDER, CO 80303 USA. NR 16 TC 30 Z9 30 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1997 VL 7 IS 2 BP 3756 EP 3761 DI 10.1109/77.622234 PN 3 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA XH867 UT WOS:A1997XH86700362 ER PT J AU Mildner, DFR ChenMayer, HH Sharov, VA Fokin, VS Reeder, PL AF Mildner, DFR ChenMayer, HH Sharov, VA Fokin, VS Reeder, PL TI The number of reflections for neutron transmission through cylindrical channels SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article AB The fraction of trajectories that have a given number of reflections during the passage of a neutron beam through a long cylindrical channel is determined when the angular divergence of the incident beam is less than the critical angle of the inner surface of the channel. This is useful for estimating the reflectivity from neutron-transmission measurements. The results are shown on a universal curve. C1 XRAY OPT SYST INC, ALBANY, NY 12205 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RUSSIAN ACAD SCI, INST PHYS & TECHNOL, MOSCOW 117218, RUSSIA. RP Mildner, DFR (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN 1 PY 1997 VL 30 BP 324 EP 326 DI 10.1107/S002188989601374X PN 3 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA XJ447 UT WOS:A1997XJ44700013 ER PT J AU Matrosov, SY AF Matrosov, SY TI Variability of microphysical parameters in high-altitude ice clouds: Results of the remote sensing method SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RADAR; CRYSTALS AB The remote sensing method for retrieving vertical profiles of microphysical parameters in ice clouds from ground-based measurements taken by the Doppler radar and IR radiometer was applied to several cloud cases observed during different field experiments including FIRE-II, ASTEX, and the Arizona Program. The measurements were performed with the NOAA Environmental Technology Laboratory instrumentation. The observed ice clouds were mostly cirrus clouds located in the upper troposphere above 5.6 km. Their geometrical thicknesses varied from a few hundred meters to 3 km. Characteristic cloud particle sizes expressed in median mass diameters of equal-volume spheres varied from about 25 mu m to more than 400 mu m. Typically, characteristic particle sizes were increasing toward the cloud base, with the exception of the lowest range gates where particles were quickly sublimating. Highest particle concentrations were usually observed near the cloud tops. The vertical variability of particle sizes inside an individual cloud could reach one order of magnitude. The standard deviation of the mean profile for a typical cloud is usually factor of 2 or 3 smaller than mean values of particle characteristic size. Typical values of retrieved cloud ice water content varied from 1 to 100 mg m(-1); however, individual variations were as high as four orders of magnitude. There was no consistent pattern in the vertical distribution of ice water content except for the rapid decrease in the vicinity of the cloud base. The relationships between retrieved cloud parameters and measured radar reflectivities were considered. The uncertainty of estimating cloud parameters from the power-law regressions is discussed. The parameters of these regressions varied from cloud to cloud and were comparable to the parameters in corresponding regressions obtained from direct particle sampling in other experiments. Relationships between cloud microphysical parameters and reflectivity can vary even for the same observational case. The variability diminishes if stronger reflectivities are considered. A procedure of ''tuning'' cloud microphysics-reflectivity regressions for individual profiles is suggested. Such a procedure can simplify the radar-radiometer method and make it applicable for a broader range of clouds. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Matrosov, SY (reprint author), NOAA,ERL,ETL,MAILCODE R-E-ET6,325 BROADWAY,BOULDER,CO 80303, USA. NR 29 TC 32 Z9 32 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUN PY 1997 VL 36 IS 6 BP 633 EP 648 DI 10.1175/1520-0450-36.6.633 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XF586 UT WOS:A1997XF58600001 ER PT J AU Ignatov, A AF Ignatov, A TI Estimation of the aerosol phase function in backscatter from simultaneous satellite and sun-photometer measurements SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID OPTICAL-PROPERTIES; ATMOSPHERIC CORRECTION; CLOUD; COLOR; ALGORITHM; THICKNESS; OCEANS; AVHRR AB The backscatter part of the aerosol phase function P-A(chi), where chi is the scattering angle, is difficult to measure from the ground. Experimental data for chi > 120 degrees are not reported in the literature. Customarily, P-A(chi) is calculated from Mie theory using an aerosol size distribution either prescribed or estimated by inversion of spectral or almucantar/aureole measurements. These results clearly require validation using direct measurements. In this paper, an empirical phase function of atmospheric aerosol over the ocean is estimated in backscatter (chi > 130 degrees) from coincident measurements of upward radiance in channel 1 (0.63 mu m) of the Advanced Very High Resolution Radiometer (AVHRR) on board National Oceanic and Atmospheric Administration satellites and sun-photometer aerosol optical thickness, delta(SP)(A). This study uses 31 sun-photometer measurements, collected during two oceanic cruises over the North Atlantic in 1989 and 1991. The accuracies of both satellite radiances and sun-photometer delta(SP)(A) are well documented. The Linearized form of the single-scattering approximation for the radiative transfer equation is used, with some adjustments to account approximately for multiple scattering effects, The newly estimated empirical phase function shows variability from one point to another, but on the average, is close to that expected for maritime aerosols as found in the literature. The results of the present study may be used to constrain the range of variability of the aerosol phase function in real marine atmospheres, which is important for aerosol retrieval from historical Coastal Zone Color Scanner (CZCS), present (AVHRR), and future satellite sensors Moderate-Resolution Imaging Spectroradiometer (MODIS), Multiangle Imaging Spectroradiometer (MISR), and Sea-Viewing-Wide-Field-of-View-Sensor (SeaWiFS). RP Ignatov, A (reprint author), NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,OFF RES & APPLICAT,CLIMATE RES & APPLICAT DIV,WASHINGTON,DC 20233, USA. RI Ignatov, Alexander/F-5594-2010 OI Ignatov, Alexander/0000-0002-7463-5944 NR 35 TC 6 Z9 7 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUN PY 1997 VL 36 IS 6 BP 688 EP 694 DI 10.1175/1520-0450(1997)036<0688:EOTAPF>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XF586 UT WOS:A1997XF58600005 ER PT J AU Lopez, RE Holle, RL Watson, AI Skindlov, J AF Lopez, RE Holle, RL Watson, AI Skindlov, J TI Spatial and temporal distributions of lightning over Arizona from a power utility perspective SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID NORTHEASTERN COLORADO; DIRECTION FINDERS; SOUTHWEST MONSOON; PATTERNS AB This study was designed to determine whether a spatially significant and temporally persistent variation in cloud-to-ground lightning frequency exists across the Salt River Project (SRP) region of central Arizona. Cloud-to-ground lightning data for 8 years from the Bureau of Land Management detection network were compiled to develop maps of lightning strike density across Arizona and the SRP region. In space, lightning frequency varied significantly across both of these topographically diverse regions. There was nearly five times more lightning over the high-altitude eastern border of the SRP region than over the lower western desert portion. The spatial pattern was consistent through time, so that more substantial lightning protection is warranted over the eastern SRP region than over the west. However, lightning frequency is highly variable from month to month and year to year on both the state and SRP scales, so that the value of newly installed lightning protection cannot be judged on experiences from a few years. C1 SALT RIVER PROJECT,PHOENIX,AZ. RP Lopez, RE (reprint author), NOAA,NATL SEVERE STORMS LAB,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. NR 13 TC 13 Z9 13 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUN PY 1997 VL 36 IS 6 BP 825 EP 831 DI 10.1175/1520-0450-36.6.825 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XF586 UT WOS:A1997XF58600017 ER PT J AU Thompson, PE Silvestre, C Jernigan, G Hobart, K Simons, DS Gregg, MR AF Thompson, PE Silvestre, C Jernigan, G Hobart, K Simons, DS Gregg, MR TI Effect of Ge on the segregation of B in Si(100) and Si(110) SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MOLECULAR-BEAM EPITAXY; SB SURFACE SEGREGATION; LOW-TEMPERATURE; SI; SILICON AB The segregation of B from Si1-xGex quantum wells grown using molecular beam epitaxy on Si(100) and Si(110) was investigated using secondary ion mass spectrometry. When a 3 nm B doping slab (n=10(19)/cm(3)) was placed in the center of a 6 nm Si1-xGex quantum well, the B profiles had two distinct exponential decay lengths, Delta(SiGe), the Ge-controlled B decay length and Delta(Si), the B decay length normally measured in Si. Delta(SiGe) was the same for Si(100) and Si(110) and independent of Ge concentration in the well for 0.1 less than or equal to x less than or equal to 0.5. As the Ge concentration was increased in the well, the location of the transition point, from Delta(SiGe) to Delta(Si), which was always found far outside of the SiGe quantum well, increased in distance from the center of the well. C1 NIST,GAITHERSBURG,MD 20899. USAF,INST TECHNOL,WRIGHT PATTERSON AFB,OH 45433. RP Thompson, PE (reprint author), USN,RES LAB,WASHINGTON,DC 20375, USA. NR 14 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1997 VL 81 IS 11 BP 7317 EP 7319 DI 10.1063/1.365359 PG 3 WC Physics, Applied SC Physics GA XC348 UT WOS:A1997XC34800030 ER PT J AU Elliott, DG Pascho, RJ Jackson, LM Matthews, GM Harmon, JR AF Elliott, DG Pascho, RJ Jackson, LM Matthews, GM Harmon, JR TI Renibacterium salmoninarum in spring-summer Chinook salmon smelts at dams on the Columbia and Snake Rivers SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article ID BACTERIAL KIDNEY-DISEASE; LINKED-IMMUNOSORBENT-ASSAY; FLUORESCENT-ANTIBODY TEST; BROOD STOCK SEGREGATION; ONCORHYNCHUS-TSHAWYTSCHA; TRANSMISSION; INFECTION; SEAWATER; PROGENY; TROUT AB We evaluated Renibacterium salmoninarum infection in smelts of hatchery and wild spring-summer chinook salmon Oncorhynchus tshawytscha sampled during most of the out-migration at Little Goose (1988) and Lower Granite dams (1988-1991) on the Snake River and at Priest Rapids and McNary dams on the Columbia River(1988-1990). We sampled 860-2,178 fish per dam each year. Homogenates of kidney-spleen tissue from all fish were tested for the presence of R. salmoninarum antigens by the enzyme-linked immunosorbent assay (ELISA), and homogenates from 10%; of the fish were examined by the fluorescent antibody technique (FAT). Although only 1-11% of fish sampled at a given dam during any 1 year exhibited lesions characteristic of bacterial kidney disease, 86-100% of the fish tested positive for R. salmoninarum antigen by ELISA, whereas 4-17% of the fish tested positive by the FAT. During most years, a majority (68-87%) of fish testing positive by the ELISA had low R. salmoninarum antigen levels, but in 1989. 53% of positive fish from Lower Granite Dam and 52% from McNary Dam showed medium-to-high antigen levels. For most years, the highest mean antigen levels were measured in fish sampled after 75% of the total out-migrants had passed a given dam. When the largest numbers of fish were being collected for bypass or downriver transportation, mean antigen levels were relatively low. C1 NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES CTR,SEATTLE,WA 98112. RP Elliott, DG (reprint author), US GEOL SURVEY,BIOL RESOURCES DIV,NW BIOL SCI CTR,6505 NE 65TH ST,SEATTLE,WA 98115, USA. NR 35 TC 35 Z9 35 U1 0 U2 4 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD JUN PY 1997 VL 9 IS 2 BP 114 EP 126 DI 10.1577/1548-8667(1997)009<0114:RSISSC>2.3.CO;2 PG 13 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA XN522 UT WOS:A1997XN52200005 ER PT J AU Fairall, CW White, AB Edson, JB Hare, JE AF Fairall, CW White, AB Edson, JB Hare, JE TI Integrated shipboard measurements of the marine boundary layer SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article; Proceedings Paper CT 7th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans CY OCT 03-07, 1994 CL NOAA ENVIRONM TECHNOL LAB, BOULDER, CO SP Int Soc Acoust Remote Sensing HO NOAA ENVIRONM TECHNOL LAB ID INERTIAL-DISSIPATION METHOD; WESTERN PACIFIC-OCEAN; SURFACE WIND STRESS; FLUX MEASUREMENTS; MICROWAVE RADIOMETER; TURBULENT FLUXES; SONIC ANEMOMETER; CLOUD PROPERTIES; TROPICAL OCEAN; WATER-VAPOR AB The NOAA Environmental Technology Laboratory air-sea interaction group and collaborators at the Woods Hole Oceanographic Institution have developed a seagoing measurement system suitable for mounting aboard ships. During its development, it was deployed on three different ships and recently completed three cruises in the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment as well as two cruises off the west coast of the United States. The system includes tower-mounted micrometeorological sensors for direct covariance flux measurements and a variety of remote sensors for profiling winds, temperature, moisture, and turbulence. A sonic anemometer/thermometer and a fast-response infrared hygrometer are used for turbulent fluxes. Winds are obtained from a stabilized Doppler radar (wind profiler) and a Doppler sodar. Returned power and Doppler width from these systems are used to deduce profiles of small-scale turbulence. A lidar ceilometer and a microwave radiometer are used to obtain cloud properties. Radiative fluxes are measured with standard pyranometers and pyrgeometers. A conventional rawinsonde system gives intermittent reference soundings. The system is used to study surface fluxes, boundary layer dynamics, cloud-radiative interactions, and entrainment. It has also proven useful in satellite calibration/validations. Following a description of the systems and methods, various examples of data and results are given from recent deployments in the North Atlantic, off the United States west coast, and in the equatorial Pacific Ocean. C1 WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543. RP Fairall, CW (reprint author), NOAA,ENVIRONM RES LABS,ENVIRONM TECHNOL LAB,R-E-ET7,325 BROADWAY,BOULDER,CO 80303, USA. NR 88 TC 80 Z9 81 U1 0 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1997 VL 14 IS 3 BP 338 EP 359 DI 10.1175/1520-0426(1997)014<0338:ISMOTM>2.0.CO;2 PN 1 PG 22 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XC594 UT WOS:A1997XC59400002 ER PT J AU Williams, CR AF Williams, CR TI Principal component analysis of wind profiler observations SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article; Proceedings Paper CT 7th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans CY OCT 03-07, 1994 CL NOAA ENVIRONM TECHNOL LAB, BOULDER, CO SP Int Soc Acoust Remote Sensing HO NOAA ENVIRONM TECHNOL LAB ID EMPIRICAL ORTHOGONAL FUNCTIONS; MESOSCALE CONVECTIVE SYSTEMS; TROPICAL PACIFIC; INTERANNUAL VARIABILITY; VERTICAL STRUCTURE; CHRISTMAS ISLAND; DIURNAL CYCLE; RADAR; OSCILLATION; SATELLITE AB Principal component analysis (PCA) is applied to wind profiler observations to study the vertical profile of the wind field and its temporal evolution. The rationale for decomposing time-height wind profiler data using PCA is twofold. The orthogonal vertical profile vectors are determined empirically from the variance of the observations, and the time evolutions of these vectors are not simple sinusoids, but are temporal varying signals that can be directly related to other measurements. As an example of its utility, PCA is used to compare the annual and interannual variation of zonal wind measured with a 50-MHz VHF wind profiler above Christmas Island, Kiribati, with the difference between surface pressures measured at Tahiti, French Polynesia, and Darwin, Australia. The high correlation coefficients relate the vertical profile of zonal wind observed in the central Pacific with the variation of convection in the western Pacific. Complex PCA (C-PCA) allows the analysis of data consisting of amplitude and phase information. It can describe the phase progression of oscillations embedded within the data. The C-PCA is applied to VHF wind profiler observations to study the seasonal behavior of the diurnal meridional wind observed above Biak, Indonesia, and the oscillatory structures of the vertical wind during a convective precipitation event observed above Darwin. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Williams, CR (reprint author), NOAA,AERON LAB,CIRES,325 BROADWAY,R-E-AL3,BOULDER,CO 80303, USA. RI Williams, Christopher/A-2723-2015 OI Williams, Christopher/0000-0001-9394-8850 NR 41 TC 3 Z9 3 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1997 VL 14 IS 3 BP 386 EP 395 DI 10.1175/1520-0426(1997)014<0386:PCAOWP>2.0.CO;2 PN 1 PG 10 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XC594 UT WOS:A1997XC59400005 ER PT J AU Hill, RJ AF Hill, RJ TI Algorithms for obtaining atmospheric surface-layer fluxes from scintillation measurements SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article; Proceedings Paper CT 7th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans CY OCT 03-07, 1994 CL NOAA ENVIRONM TECHNOL LAB, BOULDER, CO SP Int Soc Acoust Remote Sensing HO NOAA ENVIRONM TECHNOL LAB ID REFRACTIVE-INDEX SPECTRUM; INNER SCALE; OPTICAL-SCINTILLATION; KOLMOGOROV CONSTANTS; BOUNDARY-LAYER; TEMPERATURE STRUCTURE; TURBULENCE; HEAT; HUMIDITY; FLUCTUATIONS AB Algorithms are derived for obtaining atmospheric surface-layer fluxes of heat, humidity, and momentum from scintillation measurements. Both the three-wavelength and two-wavelength methods are examined, as is combining the two-wavelength method with other micrometeorological measurements. Corrections for the effects of strong scintillation are discussed. Deriving turbulence inner-scale and refractive structure parameters from scintillation variances is discussed, as is using these quantities to obtain the energy dissipation rate and structure parameters of temperature and humidity. Given these latter quantities, Monin-Obukhov similarity theory is applied to specific humidity and temperature (equivalently, potential temperature) to obtain the fluxes. RP NOAA, ENVIRONM RES LABS, ENVIRONM TECHNOL LAB, 325 BROADWAY, BOULDER, CO 80303 USA. NR 63 TC 47 Z9 48 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 EI 1520-0426 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1997 VL 14 IS 3 BP 456 EP 467 DI 10.1175/1520-0426(1997)014<0456:AFOASL>2.0.CO;2 PN 1 PG 12 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XC594 UT WOS:A1997XC59400010 ER PT J AU Han, Y Westwater, ER Ferrare, RA AF Han, Y Westwater, ER Ferrare, RA TI Applications of Kalman filtering to derive water vapor profiles from Raman lidar and microwave radiometers SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article; Proceedings Paper CT 7th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans CY OCT 03-07, 1994 CL NOAA ENVIRONM TECHNOL LAB, BOULDER, CO SP Int Soc Acoust Remote Sensing HO NOAA ENVIRONM TECHNOL LAB ID TEMPERATURE; ATMOSPHERE; AEROSOLS; SENSORS AB A two-stage retrieval technique is presented for deriving water vapor profiles from data provided by a Raman lidar, a microwave radiometer, a radio acoustic sounding system, and surface in situ instruments. In the first stage, a Kalman filtering algorithm is applied to derive water vapor profiles using surface in situ and current and past Raman measurements. In the second stage, a statistical inversion technique is applied to combine the Kalman retrieval with radiometric and climatological data. This retrieval method is tested using data collected during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment II experiment. The method is demonstrated to provide accurate profiles at altitudes above which the Raman lidar technique is limited. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. HUGHES STX CORP,LANHAM,MD. RP Han, Y (reprint author), NOAA,ENVIRONM RES LAB,ENVIRONM TECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Han, Yong/F-5590-2010 OI Han, Yong/0000-0002-0183-7270 NR 23 TC 5 Z9 5 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1997 VL 14 IS 3 BP 480 EP 487 DI 10.1175/1520-0426(1997)014<0480:AOKFTD>2.0.CO;2 PN 1 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XC594 UT WOS:A1997XC59400012 ER PT J AU Matejka, T Lewis, SA AF Matejka, T Lewis, SA TI Improving research aircraft navigation by incorporating INS and GPS information in a variational solution SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article; Proceedings Paper CT 7th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans CY OCT 03-07, 1994 CL NOAA ENVIRONM TECHNOL LAB, BOULDER, CO SP Int Soc Acoust Remote Sensing HO NOAA ENVIRONM TECHNOL LAB ID NOAAS P-3 AIRCRAFT; INERTIAL NAVIGATION; LORAN-C AB With the new (potentially more accurate) Global Position System (GPS) measurements available, aircraft navigation systems are significantly improved. Since the GPS can drop out occasionally and exhibit other intermittent errors, it cannot be used exclusively for all navigational needs. The traditional Inertial Navigation System (INS) position and velocity measurements, on the other hand, suffer from large Schuler oscillation and drift errors over the duration of a flight. This work proposes and tests a variational method to determine improved aircraft positions and velocities when both INS and GPS data are available. This technique incorporates GPS position and velocity data and INS acceleration data. The data are weighted by the reciprocal of the variance of their errors. Error characteristics of the data are determined objectively by examining the internal consistency of the data themselves. The resulting improved position and velocity time series are fully internally consistent. The data used for this project come from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment field program conducted from November 1992 to February 1993. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Matejka, T (reprint author), NOAA,NATL SEVERE STORMS LAB,ENVIRONM RES LABS,N-C MRD,325 BROADWAY,BOULDER,CO 80303, USA. NR 14 TC 11 Z9 11 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1997 VL 14 IS 3 BP 495 EP 511 DI 10.1175/1520-0426(1997)014<0495:IRANBI>2.0.CO;2 PN 1 PG 17 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XC594 UT WOS:A1997XC59400014 ER PT J AU Jordan, JR Lataitis, RJ AF Jordan, JR Lataitis, RJ TI A potential source of bias in horizontal winds estimated using a 915-MHz acoustically enhanced profiler SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article; Proceedings Paper CT 7th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans CY OCT 03-07, 1994 CL NOAA ENVIRONM TECHNOL LAB, BOULDER, CO SP Int Soc Acoust Remote Sensing HO NOAA ENVIRONM TECHNOL LAB ID RASS; ACCURACY AB Clear-air Doppler wind profilers perform poorly in dry, calm conditions when reflectivities are low. One solution to this problem is to use acoustic waves, generated by a collocated acoustic source, as the scattering target instead of clear-air turbulence. The idea for such an acoustically enhanced profiler was proposed more than 10 years ago. In a recent Antarctic experimental campaign, a vertically pointing acoustic source was used to extend the coverage of a standard four-beam 915-MHz wind profiler. Preliminary testing of the system revealed large biases in the retrieved wind profiles. A simple theory and a limited dataset suggest that the observed biases are consistent with a nonuniform acoustic illumination of the radar beams caused by the different acoustic and radar beam pointing angles. Our results suggest that this bias can be eliminated by aligning the acoustic and radar beams. C1 NOAA,ERL,ENVIRONM TECHNOL LAB,BOULDER,CO 80303. NR 11 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1997 VL 14 IS 3 BP 543 EP 546 DI 10.1175/1520-0426(1997)014<0543:APSOBI>2.0.CO;2 PN 1 PG 4 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XC594 UT WOS:A1997XC59400019 ER PT J AU Angevine, WM AF Angevine, WM TI Errors in mean vertical velocities measured by boundary layer wind profilers SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article; Proceedings Paper CT 7th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans CY OCT 03-07, 1994 CL NOAA ENVIRONM TECHNOL LAB, BOULDER, CO SP Int Soc Acoust Remote Sensing HO NOAA ENVIRONM TECHNOL LAB ID HEAT-FLUX AB The accuracy of vertical velocities measured by UHF wind-profiling radars has been a matter of discussion for some time. This paper shows that there are significant errors in mean vertical velocities measured by the vertical beam of 915-MHz wind profilers. The erroneous Velocities are 0.1-0.3 m s(-1) downward in daytime convective boundary layers over two sites, hat farmland in Illinois and rolling forest in Wisconsin. Velocities at night are not affected, and different days have different erroneous velocities. The directly measured velocities are compared to vertical velocities calculated from the divergence of the horizontal wind to show that they are indeed in error. The erroneous velocities are not caused by delectable rain, by an error in the beam pointing direction, or by the skewness of the vertical velocity distribution. They are probably due to small targets (particulate scatterers) that have a small fall velocity and are detected by the radar. An online algorithm for removing intermittent contamination reduces the error, but does not eliminate it. The fluctuating component of the velocity is not affected by these errors since it is much larger in magnitude. C1 UNIV COLORADO,CIRES,BOULDER,CO 80309. RP Angevine, WM (reprint author), NOAA,AERON LAB,325 BROADWAY,R-E-AL3,BOULDER,CO 80303, USA. RI Angevine, Wayne/H-9849-2013 OI Angevine, Wayne/0000-0002-8021-7116 NR 13 TC 52 Z9 53 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1997 VL 14 IS 3 BP 565 EP 569 DI 10.1175/1520-0426(1997)014<0565:EIMVVM>2.0.CO;2 PN 1 PG 5 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA XC594 UT WOS:A1997XC59400022 ER PT J AU Brooks, SB Crawford, TL Oechel, WC AF Brooks, SB Crawford, TL Oechel, WC TI Measurement of carbon dioxide emissions plumes from Prudhoe Bay, Alaska oil fields SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE carbon dioxide; emissions; oil production ID CO2 AB Large carbon dioxide plumes with concentrations up to 45 ppm above ambient levels were measured about 15 km downwind of the Prudhoe Bay, Alaska major oil production facilities, located at 70 degrees N Lat, above the Arctic Circle, The measured emissions were 1.3 x 10(3) metric tons (C) hour(-1) (11.4 x 10(6) metric tons (C) year(-1)), six times greater than the combustion emissions assumed by Jaffe and coworkers in J. Atmos. Chem. 20 (1995), 213-227, based on 1989 reported Prudhoe Bay oil facility fuel consumption data, and four times greater than the total C emissions reported by the oil facilities for the same months as the measurement time periods. Variations in the emissions were estimated by extrapolating the observed emissions at a single altitude for all tundra research transect flights conducted downwind of the oil fields. These 30 flights yielded an average emission rate of 1.02 x 10(3) metric tons (C) hour(-1) with a standard deviation of 0.33 x 10(3). These quantity of emissions are roughly equivalent to the carbon dioxide emissions of 7-10 million hectares of arctic tussock tundra (Oechel and Vourlitis, Trends in Ecol. Evolution 9 (1994), 324-329). C1 SAN DIEGO STATE UNIV,DEPT BIOL,SAN DIEGO,CA 92182. RP Brooks, SB (reprint author), NOAA,ATMOSPHER TURBULENCE & DIFFUS DIV,456 S ILLINOIS AVE,POB 2456,OAK RIDGE,TN 37831, USA. RI Oechel, Walter/F-9361-2010 OI Oechel, Walter/0000-0002-3504-026X NR 14 TC 11 Z9 11 U1 0 U2 6 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 JUN PY 1997 VL 27 IS 2 BP 197 EP 207 DI 10.1023/A:1005890318796 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA YD259 UT WOS:A1997YD25900005 ER PT J AU Chen, TH Henderson-Sellers, A Milly, PCD Pitman, AJ Beljaars, ACM Polcher, J Abramopoulos, F Boone, A Chang, S Chen, F Dai, Y Desborough, CE Dickinson, RE Dumenil, L Ek, M Garratt, JR Gedney, N Gusev, YM Kim, J Koster, R Kowalczyk, EA Laval, K Lean, J Lettenmaier, D Liang, X Mahfouf, JF Mengelkamp, HT Mitchell, K Nasonova, ON Noilhan, J Robock, A Rosenzweig, C Schaake, J Schlosser, CA Schulz, JP Shao, Y Shmakin, AB Verseghy, DL Wetzel, P Wood, EF Xue, Y Yang, ZL Zeng, Q AF Chen, TH Henderson-Sellers, A Milly, PCD Pitman, AJ Beljaars, ACM Polcher, J Abramopoulos, F Boone, A Chang, S Chen, F Dai, Y Desborough, CE Dickinson, RE Dumenil, L Ek, M Garratt, JR Gedney, N Gusev, YM Kim, J Koster, R Kowalczyk, EA Laval, K Lean, J Lettenmaier, D Liang, X Mahfouf, JF Mengelkamp, HT Mitchell, K Nasonova, ON Noilhan, J Robock, A Rosenzweig, C Schaake, J Schlosser, CA Schulz, JP Shao, Y Shmakin, AB Verseghy, DL Wetzel, P Wood, EF Xue, Y Yang, ZL Zeng, Q TI Cabauw experimental results from the project for intercomparison of land-surface parameterization schemes SO JOURNAL OF CLIMATE LA English DT Article ID ANNUAL WATER-BALANCE; SOIL-MOISTURE; BIOSPHERE MODEL; BOUNDARY-LAYER; ECMWF MODEL; CLIMATE; HYDROLOGY; STORAGE; FLUXES; GCMS AB In the Project for Intercomparison of Land-Surface Parameterization Schemes phase 2a experiment, meteorological data for the year 1987 from Cabauw, the Netherlands, were used as inputs to 23 land-surface flux schemes designed for use in climate and weather models. Schemes were evaluated by comparing their outputs with long-term measurements of surface sensible heat fluxes into the atmosphere and the ground, and of upward longwave radiation and total net radiative fluxes, and also comparing them with latent heat fluxes derived from a surface energy balance. Tuning of schemes by use of the observed flux data was not permitted. On an annual basis, the predicted surface radiative temperature exhibits a range of 2 K across schemes, consistent with the range of about 10 W m(-2) in predicted surface net radiation. Most modeled values of monthly net radiation differ from the observations by less than the estimated maximum monthly observational error (+/-10 W m(-2)). However, modeled radiative surface temperature appears to have a systematic positive bias in most schemes; this might be explained by an error in assumed emissivity and by models' neglect of canopy thermal heterogeneity. Annual means of sensible and latent heat fluxes, into which net radiation is partitioned, have ranges across schemes of 30 W m(-2) and 25 W m(-2), respectively. Annual totals of evapotranspiration and runoff, into which the precipitation is partitioned, both have ranges of 315 mm. These ranges in annual heat and water fluxes were approximately halved upon exclusion of the three schemes that have no stomatal resistance under non-water-stressed conditions. Many schemes tend to underestimate latent heat flux and overestimate sensible heat flux in summer, with a reverse tendency in winter. For six schemes, root-mean-square deviations of predictions from monthly observations are less than the estimated upper bounds on observation errors (5 W m(-2) for sensible heat flux and 10 W m(-2) for latent heat flux). Actual runoff at the site is believed to be dominated by vertical drainage to groundwater, but several schemes produced significant amounts of runoff as overland flow or interflow. There is a range across schemes of 184 mm (40% of total pore volume) in the simulated annual mean root-zone soil moisture. Unfortunately, no measurements of soil moisture were available for model evaluation. A theoretical analysis suggested that differences in boundary conditions used in various schemes are not sufficient to explain the large variance in soil moisture. However, many of the extreme values of soil moisture could be explained in terms of the particulars of experimental setup or excessive evapotranspiration. C1 MACQUARIE UNIV, CLIMAT IMPACTS CTR, SYDNEY, NSW 2109, AUSTRALIA. US GEOL SURVEY, PRINCETON, NJ USA. NOAA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ USA. ROYAL NETHERLANDS METEOROL INST, NL-3730 AE DE BILT, NETHERLANDS. CNRS, METEOROL DYNAM LAB, PARIS, FRANCE. SCI SYST & APPLICAT INC, NEW YORK, NY USA. NASA, GODDARD SPACE FLIGHT CTR, MESOSCALE DYNAM & PRECIPITAT BRANCH, GREENBELT, MD 20771 USA. PHILLIPS LAB, GPAB, HANSCOM AFB, MA USA. NOAA, DEV DIV, NATL CTR ENVIRONM PREDICT, CAMP SPRINGS, MD USA. CHINESE ACAD SCI, INST ATMOSPHER PHYS, BEIJING, PEOPLES R CHINA. UNIV ARIZONA, INST ATMOSPHER PHYS, TUCSON, AZ 85721 USA. MAX PLANCK INST METEOROL, HAMBURG, GERMANY. CSIRO, DIV ATMOSPHER RES, ASPENDALE, VIC 3195, AUSTRALIA. UNIV READING, DEPT METEOROL, READING, BERKS, ENGLAND. RUSSIAN ACAD SCI, INST WATER PROBLEMS, MOSCOW 103064, RUSSIA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA USA. NASA, GODDARD SPACE FLIGHT CTR, HYDROL SCI BRANCH, GREENBELT, MD 20771 USA. METEOROL OFF, HADLEY CTR CLIMATE PREDICT & RES, BRACKNELL, BERKS, ENGLAND. UNIV WASHINGTON, DEPT CIVIL ENGN, SEATTLE, WA 98195 USA. PRINCETON UNIV, DEPT CIVIL ENGN & OPERAT RES, PRINCETON, NJ 08544 USA. ECMWF, READING, BERKS, ENGLAND. GKSS FORSCHUNGSZENTRUM GEESTHACHT GMBH, INST ATMOSPHER PHYS, GEESTHACHT, GERMANY. METEO FRANCE, CNRM, TOULOUSE, FRANCE. UNIV MARYLAND, DEPT METEOROL, COLLEGE PK, MD 20742 USA. NATL WEATHER SERV, NOAA, OFF HYDROL, SILVER SPRING, MD USA. UNIV NEW S WALES, CTR ADV NUMER COMPUTAT ENGN & SCI, SYDNEY, NSW, AUSTRALIA. INST GEOG, MOSCOW, RUSSIA. ATMOSPHER ENVIRONM SERV, CLIMATE RES BRANCH, DOWNSVIEW, ON, CANADA. CTR OCEAN LAND ATMOSPHERE STUDIES, CALVERTON, MD USA. RI Shao, Yaping/G-3606-2013; Dai, Yongjiu/D-6261-2014; Yang, Zong-Liang/B-4916-2011; Pitman, Andrew/A-7353-2011; Henderson-Sellers, Ann/H-5323-2011; Koster, Randal/F-5881-2012; Chen, Fei/B-1747-2009; lettenmaier, dennis/F-8780-2011; Nasonova, Olga/B-6093-2014; gusev, yugeniy/G-4711-2014; Robock, Alan/B-6385-2016 OI Wood, Eric/0000-0001-7037-9675; Shao, Yaping/0000-0002-2041-5479; Dai, Yongjiu/0000-0002-3588-6644; Pitman, Andrew/0000-0003-0604-3274; Koster, Randal/0000-0001-6418-6383; lettenmaier, dennis/0000-0003-3317-1327; gusev, yugeniy/0000-0003-3886-2143; NR 49 TC 229 Z9 245 U1 3 U2 28 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD JUN PY 1997 VL 10 IS 6 BP 1194 EP 1215 DI 10.1175/1520-0442(1997)010<1194:CERFTP>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XJ208 UT WOS:A1997XJ20800004 ER PT J AU Chen, WY VandenDool, HM AF Chen, WY VandenDool, HM TI Atmospheric predictability of seasonal, annual, and decadal climate means and the role of the ENSO cycle: A model study SO JOURNAL OF CLIMATE LA English DT Article ID NATIONAL-METEOROLOGICAL-CENTER; GENERAL-CIRCULATION MODEL; NUMERICAL WEATHER PREDICTION; DYNAMICAL PREDICTABILITY; SOUTHERN OSCILLATION; FORECAST EXPERIMENTS; TIME AVERAGES; VARIABILITY; ANOMALIES; SKILL AB The characteristics of extratropical low-frequency variability are examined using a comprehensive atmospheric general circulation model. A large experiment consisting of 13 45-yr-long integrations forced by prescribed sea surface temperature (SST) variations is analyzed. The predictability of timescales of seasonal to decadal averages is evaluated. The variability of a climate mean contains not only climate signal arising from external boundary forcing but also climate noise due to the internal dynamics of the climate system, resulting in various levels of predictability that are dependent on the forcing boundary conditions and averaging timescales. The focus of this study deviates from the classic predictability study of Lorenz, which is essentially initial condition sensitive. This study can be considered to be a model counterpart of Madden's ''potential'' predictability study. The tropical SST anomalies impact more on the predictability over the Pacific/North America sector than the Atlantic/Eurasia sector. In the former sector, more significant and positive impacts are found during El Nino and La Nina phases of the ENSO cycle than during the ENSO inactive period of time, Furthermore, the predictability is significantly higher during El Nino than La Nina phases of the ENSO cycle. The predictability of seasonal means exhibits large seasonality for both warm and cold phases of the ENSO cycle. During the warm phases, a high level of predictability is observed from December to April. During the cool phases, the predictability rapidly drops to below normal from November to March, The spring barrier in the atmospheric predictability is therefore a distinct phenomenon for the cold phase, not the warm phase, of the ENSO cycle. The cause of the barrier can be traced to the smaller climate signal and larger climate noise generated during cold events, which in turn can be traced back to the rapidly weakening negative SST anomalies in the tropical Pacific east of the date line. Due to the fact that the signal to noise ratio of this model climate system is very small, an upper bound in atmospheric predictability is present, even when a perfect model atmosphere is considered and large ensemble mean predictions are exploited. The outstanding issues of the dynamical short-term climate prediction employing an atmospheric general circulation model are examined, the current model deficiencies identified, and continuing efforts in model development addressed. C1 NATL WEATHER SERV,CLIMATE PREDICT CTR,NOAA,NCEP,WASHINGTON,DC. NR 50 TC 29 Z9 33 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUN PY 1997 VL 10 IS 6 BP 1236 EP 1254 DI 10.1175/1520-0442(1997)010<1236:APOSAA>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XJ208 UT WOS:A1997XJ20800006 ER PT J AU Zhang, RH Levitus, S AF Zhang, RH Levitus, S TI Interannual variability of the coupled tropical Pacific ocean-atmosphere system associated with the El Nino southern oscillation SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODELS; HEAT-CONTENT VARIABILITY; SEA-SURFACE TEMPERATURE; ROSSBY WAVES; ENSO; GCM; SIMULATION; RESOLUTION; CYCLES; WIND AB Upper-ocean temperature and surface marine meteorological observations are used to examine interannual variability of the coupled tropical Pacific climate system. The basinwide structure and evolution of meteorological and oceanographic fields associated with ENSO events are described using composites, empirical orthogonal functions, and a lagged correlation analysis. The analyses reveal well-defined spatial structures and coherent phase relations among various anomaly fields. There are prominent seesaw patterns and orderly movement of subsurface ocean thermal anomalies. During an El Nino year, positive temperature anomalies occur in the eastern and central tropical Pacific upper ocean. Westerly wind anomalies, displaced well to the west of SST anomalies, occur over the western and central equatorial region. These patterns are accompanied by subsurface negative temperature anomalies in the west, with maxima located at thermocline depths off the equator. A reverse pattern is observed during La Nina. The ENSO evolution is characterized by a very slow propagation of subsurface thermal anomalies around the tropical Pacific basin, showing consistent and coherent oceanic variations in the west and in the east, at subsurface depths and at the sea surface, and on the equator and off the equator of the tropical North pacific. A common feature associated with the onset of El Nino is an appearance of subsurface thermal anomalies in the western Pacific Ocean, which propagate systematically eastward along the equator. Their arrival to the east results in a reversal of SST anomaly polarity, which then correspondingly produces surface wind anomalies in the west, which in turn produce and intensify the subsurface anomalies off the equator, thus terminating one phase of the Southern Oscillation. At the same time, the continual anomaly movement at depth from east to west off the equator provides a phase transition mechanism back to the west. In due course, opposite anomalies are located in the subsurface equatorial western Pacific, introducing an opposite SO phase and beginning a new cycle. Therefore, the phase transitions at the sea surface in the east and at depth in the west are both caused by these preferential, slowly propagating subsurface temperature anomalies, which are essential to the ENSO evolution. Their cycling time around the tropical Pacific basin may determine the period of the El Nino occurrence. The authors' data analyses show an important role of the thermocline displacement in producing and phasing SST anomalies in the eastern and central equatorial Pacific. The coherent subsurface anomaly movement and its phase relation with SST and surface winds determine the nature of interannual variability and provide an oscillation mechanism for the tropical Pacific climate system. It appears that interannual variability represents a slowly evolving air-sea coupled mode, rather than individual free oceanic Rossby and Kelvin wave modes. These results provide an observational basis for verifying theoretical studies and model simulations. C1 NOAA,NATL OCEANOG DATA CTR,OCEAN CLIMATE LAB,SILVER SPRING,MD. NR 49 TC 47 Z9 55 U1 0 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUN PY 1997 VL 10 IS 6 BP 1312 EP 1330 DI 10.1175/1520-0442(1997)010<1312:IVOTCT>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XJ208 UT WOS:A1997XJ20800010 ER PT J AU Bony, S Sud, Y Lau, KM Susskind, J Saha, S AF Bony, S Sud, Y Lau, KM Susskind, J Saha, S TI Comparison and satellite assessment of NASA/DAO and NCEP-NCAR reanalyses over tropical ocean: Atmospheric hydrology and radiation SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; SEASONAL-VARIATION; BUDGET EXPERIMENT; WATER-VAPOR; PARAMETERIZATION; CLOUDS; MODEL; ERBE; FLUX; INTERPOLATION AB This study compares the atmospheric reanalyses that have been produced independently at the Data Assimilation Office (DAO) of Goddard Laboratory for Atmospheres and at the National Centers for Environmental Prediction (NCEP). These reanalyses were produced by using a frozen state-of-the-art version of the global data assimilation system developed at these two centers. For the period 1987-88 and for the tropical oceanic regions of 30 degrees S-30 degrees N, surface and atmospheric fields related to atmospheric hydrology and radiation are compared and assessed, wherever possible, with satellite data. Some common biases as well as discrepancies between the two independent reassimilation products are highlighted. Considering both annual averages and interannual variability (1987-88), discrepancies between DAO and NCEP reanalysis in water vapor, precipitation, and clear-sky longwave radiation at the top of the atmosphere are generally smaller than discrepancies that exist between corresponding satellite estimates. Among common biases identified in the reanalyses, the authors note an underestimation of the total precipitable water and an overestimation of the shortwave cloud radiative forcing in warm convective regions. Both lead to an underestimation of the surface radiation budget. The authors also note an overestimaton of the clear-sky outgoing longwave radiation in most tropical ocean regions, as well as an overestimation of the longwave radiative cooling at the ocean surface. Surface latent and sensible heat fluxes differ by about 20 and 3 W m(-2), respectively, in the two reanalyses, Differences in the surface radiation budget are larger than the uncertainties of satellite-based estimates. Biases in the surface radiation fluxes derived from the reanalyses are primarily due to incorrect shortwave cloud radiative forcing and, to a lesser degree, due to a deficit in the total precipitable water and a cold bias at lower-tropospheric. temperatures. This study suggests that individual features and biases of each set of reanalyses should be carefully studied, especially when using analyzed surface fluxes to force other physical or geophysical models such as ocean circulation models. Over large regions of the tropical oceans, DAO and NCEP reanalyses produce surface net heat fluxes that can differ by up to 50 W m(-2) in the average and by a factor of 2 when considering interannual anomalies. This may lead to vastly different thermal forcings for driving ocean circulations. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. NATL CTR ENVIRONM PREDICT, WASHINGTON, DC USA. RP Bony, S (reprint author), ECOLE NORMALE SUPER, CNRS, METEOROL DYNAM LAB, 24 RUE LHOMOND, F-75231 PARIS 05, FRANCE. RI Lau, William /E-1510-2012; OI Lau, William /0000-0002-3587-3691; Bony, Sandrine/0000-0002-4791-4438 NR 65 TC 48 Z9 49 U1 0 U2 1 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 JUN PY 1997 VL 10 IS 6 BP 1441 EP 1462 DI 10.1175/1520-0442(1997)010<1441:CASAON>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XJ208 UT WOS:A1997XJ20800018 ER PT J AU Kucklick, JR Sivertsen, SK Sanders, M Scott, GI AF Kucklick, JR Sivertsen, SK Sanders, M Scott, GI TI Factors influencing polycyclic aromatic hydrocarbon distributions in South Carolina estuarine sediments SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE polycyclic aromatic hydrocarbons; principal components analysis; sediments; South Carolina; urban runoff ID SOUTHEASTERN UNITED-STATES; TIDAL RIVER SEDIMENTS; ORGANIC CONTAMINANTS; GEOCHEMICAL SIGNIFICANCE; PETROLEUM-HYDROCARBONS; LAKE-SUPERIOR; URBAN RUNOFF; 2 ESTUARIES; DC AREA; BAY AB Surface (2 cm) sediment was collected from three South Carolina estuaries, Winyah Bay, Charleston Harbor and the North Edisto River estuary for a total of 64 samples. The sediment samples were analyzed for 24 individual polycyclic aromatic hydrocarbons (PAHs; two to six rings) by gas chromatography with ion trap mass spectrometric detection. Concentrations of total PAHs were extremely variable, ranging from 33 ng/g dry weight in the Edisto River estuary to 9600 ng/g dry weight in some areas of urbanized Charleston Harbor. The observed variability was not explained by total organic carbon or grain size, indicating that other factors were more important, such as the proximity of the sampling location to sources. Principal components analysis was performed on the percentage of total PAHs, to examine factors that account for the variability of distribution of individual PAHs in a sample. Considering this analysis, the first principal component accounted for 65% of the variability and was related to variations in perylene, a non-anthropogenically produced PAH. The principal components calculated on the PAH distributions in the absence of perylene were related to the fraction of pyrogenic and petroleum-based PAHs in the samples. The majority of the samples with pyrogenic PAH signatures were located adjacent to urban areas, suggesting that the source was urban runoff, whereas samples with petroleum signatures were generally from rural areas. (C) 1997 Elsevier Science B.V. C1 UNIV MARYLAND,CTR ENVIRONM & ESTUARINE STUDIES,CHESAPEAKE BIOL LAB,SOLOMONS,MD 20688. RP Kucklick, JR (reprint author), SE FISHERIES CTR,CHARLESTON LAB,NATL MARINE FISHERIES SERV,219 FT JOHNSON RD,CHARLESTON,SC 29412, USA. NR 37 TC 66 Z9 67 U1 1 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD JUN 1 PY 1997 VL 213 IS 1 BP 13 EP 29 DI 10.1016/S0022-0981(97)00007-5 PG 17 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA XD292 UT WOS:A1997XD29200003 ER PT J AU Siewicki, TC AF Siewicki, TC TI Environmental modeling and exposure assessment of sediment-associated fluoranthene in a small, urbanized, non-riverine estuary SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE exposure analysis; fluoranthene; modeling; oysters; polycyclic aromatic hydrocarbons ID POLYCYCLIC AROMATIC-HYDROCARBONS; EXTRACTABLE ORGANIC-MATTER; STORMWATER RUNOFF; WATER; RATES; PAH; CONTAMINANTS; CHEMICALS; BEHAVIOR; ROADWAY AB Risks posed by fluoranthene (a four-ring polycyclic aromatic hydrocarbon) in urban runoff were estimated by modeling and exposure assessment of a portion of Murrells Inlet, South Carolina, United States. Kinetic rate constants for sediment-associated fluoranthene and fluoranthene runoff concentrations that were determined in earlier studies were used in these assessments. Computer modeling was used to simultaneously integrate environmental conditions and loading in the estuary with the physico-chemical characteristics of fluoranthene. The Exposure Analysis Modeling System (EXAMS-II) quantitatively characterized relationships between land uses and fluoranthene distribution and fate. Factors predicted to affect oyster exposure were: Non-point source runoff loading > base (background) loading > non-point source hydrologic flows. Simulated pulse loads were predicted to cause only nearby, short-term increases. These results suggest that bioconcentration of fluoranthene by oysters is related to adjacent land uses and can be predicted by understanding the major factors affecting its transport and fate. An approach is described that can be used to test alternate landscape modifications for minimizing impacts on both resident fauna and seafood consumers. (C) 1997 Elsevier Science B.V. RP Siewicki, TC (reprint author), NATL OCEAN & ATMOSPHER ADMIN,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,CHARLESTON LAB,CHARLESTON,SC 29412, USA. NR 76 TC 12 Z9 12 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD JUN 1 PY 1997 VL 213 IS 1 BP 71 EP 94 DI 10.1016/S0022-0981(97)00010-5 PG 24 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA XD292 UT WOS:A1997XD29200006 ER PT J AU Redford, S Blackman, MJ AF Redford, S Blackman, MJ TI Luster and fritware production and distribution in medieval Syria SO JOURNAL OF FIELD ARCHAEOLOGY LA English DT Article AB The production of glazed fritware (artificial paste bodied) ceramics in medieval Syria is examined in the light of neutron activation analysis of an excavated sample from the site of Gritille. Reevaluation casts doubt on two main commonplaces of Islamic ceramic history: 1) the decorative technique of lustering, used on some of these fritwares, was highly restricted; and 2) the production of such luxury ceramics in the medieval Islamic world in general was centralized We propose that regional ceramic production corresponded to the decentralized system of government then current in Syria and other geographic and demographic factors there. C1 NIST,CAL,INSTRUMENTAL NEUTRON ACTIVAT ANAL FACIL,GAITHERSBURG,MD 20899. SMITHSONIAN INST,CONSERVAT ANALYT LAB,WASHINGTON,DC 20560. RP Redford, S (reprint author), GEORGETOWN UNIV,SCH FOREIGN SERV,WASHINGTON,DC 20057, USA. NR 34 TC 3 Z9 3 U1 0 U2 0 PU JOURNAL FIELD ARCHAEOLOGY PI BOSTON PA BOSTON UNIV 675 COMMONWEALTH AVE, BOSTON, MA 02215 SN 0093-4690 J9 J FIELD ARCHAEOL JI J. Field Archaeol. PD SUM PY 1997 VL 24 IS 2 BP 233 EP 247 DI 10.2307/530474 PG 15 WC Archaeology SC Archaeology GA XF810 UT WOS:A1997XF81000007 ER PT J AU Olla, BL Davis, MW Schreck, CB AF Olla, BL Davis, MW Schreck, CB TI Effects of simulated trawling on sablefish and walleye pollock: The role of light intensity, net velocity and towing duration SO JOURNAL OF FISH BIOLOGY LA English DT Article DE behaviour; bycatch; cortisol; mortality; stress; towing speed ID PLASMA-CORTISOL CONCENTRATIONS; SCOMBER-SCOMBRUS L; STRESS RESPONSES; CHINOOK SALMON; ONCORHYNCHUS-TSHAWYTSCHA; HANDLING STRESS; COHO SALMON; NORTH-SEA; SURVIVAL; FISH AB Laboratory apparatus which simulated capture of fish in the cod-end of a towed trawl was used to induce post-capture stress as measured by alterations in behavioural, physiological and mortality indices in juvenile walleye pollock Theragra chalcogramma and juvenile and adult sablefish Anoplopoma fimbria. Differences in resistance to net entrainment varied between species with the severity of stress and the potential for recovery depending on light intensity, net velocity and towing duration. At a light intensity which simulated daylight at depth in clear ocean water (0.5 mu mol photons m(-2) s(-1)), walleye pollock juveniles were able to maintain swimming in nets towed at 0.65 m s(-1) for 3 h with no discernible effects on behaviour or mortality. However, when net velocity was increased to >0.75 m s(-1) or light intensity was decreased to <0.002 mu mol photons m(-2) s(-1), fish became entrained in the meshes of the net and exhibited significant alterations in feeding behaviour, predator evasion and increases in plasma cortisol concentrations. Marked increases in stress-induced mortality also occurred, in some cases after a delay of 6 days and eventually reaching 100%. In comparison with walleye pollock, sablefish juveniles became entrained in the meshes of the net at higher velocities (>0.92 m s(-1)) or lower light intensities (<0.0004 mu mol photons m(-2) s(-1)) and were much more resistant to post-capture stress. Towing of net-entrained fish for 15 min caused no detectable changes in feeding and cortisol and for 2 h, no changes in feeding although mortality increased from 0% for 15-min tows to 19% for 2-h tows. Towing for 4 h caused significant alterations in feeding and cortisol with feeding recovering to control levels by 6 days and cortisol by 3 days; mortality was 25%. When adult sablefish were towed for 4 h followed by 15-min exposure to air, feeding was inhibited 6 days after towing, but recovered within 30 days with no mortality observed after 30 days. The results demonstrate the value of using laboratory-based behavioural and biochemical indices to identify factors that may potentially affect post-capture survival among different species of fish. (C) 1997 The Fisheries Society of the British Isles. C1 OREGON STATE UNIV,DEPT FISHERIES & WILDLIFE,OREGON COOPERAT FISHERY RES UNIT,US NATL BIOL SERV,CORVALLIS,OR 97331. RP Olla, BL (reprint author), OREGON STATE UNIV,HATFIELD MARINE SCI CTR,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,NEWPORT,OR 97365, USA. NR 35 TC 58 Z9 60 U1 4 U2 14 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JUN PY 1997 VL 50 IS 6 BP 1181 EP 1194 DI 10.1111/j.1095-8649.1997.tb01646.x PG 14 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XF362 UT WOS:A1997XF36200004 ER PT J AU Poysky, FT Paranjpye, RN Peterson, ME Pelroy, GA Guttman, AE Eklund, MW AF Poysky, FT Paranjpye, RN Peterson, ME Pelroy, GA Guttman, AE Eklund, MW TI Inactivation of Listeria monocytogenes on hot-smoked salmon by the interaction of heat and smoke or liquid smoke SO JOURNAL OF FOOD PROTECTION LA English DT Article DE Listeria monocytogenes; heat inactivation; smoke; liquid smoke ID MOIST HEAT; RAW-MILK; SURVIVAL; STORAGE; POPULATIONS; INHIBITION; PRODUCTS; POULTRY; GROWTH; FOODS AB L. monocytogenes was inoculated onto the surface of brined salmon steaks and heat processed in a commercial smokehouse to simulate a hot process for preparing smoked fish. The minimum temperature required for inactivation of L. monocytogenes was 153 degrees F (67.2 degrees C) when generated smoke was applied throughout the entire process. When generated smoke was added only during the last half of the process, L. monocyrogenes was recovered from steaks heated to temperatures as high as 176 degrees C (80.0 degrees C). When smoke was not applied during the process, L. monocytogenes survived on steaks heated to internal temperatures between 131 degrees and 181 degrees F(55.0 to 82.8 degrees C) but was not isolated from steaks heated above 181 degrees F (82.8 degrees C). When liquid smoke CharSol C-10 was applied as a full-strength (100%) dip before processing, L. monocytogenes was inactivated in samples processed at temperatures as low as 138 degrees F (58.9 degrees C). When liquid smoke 10-Poly or CharSol C-10 was applied at a concentration of 50%, the lethal temperature was increased to the range of 145 to 150 degrees F(62.8 to 65.6 degrees C). With further dilution of C-10 to 25% and 10% the inactivation temperatures increased to 156 degrees F (68.9 degrees C) and 163 degrees F (72.8 degrees C). A full-strength dip of CharOil, the oil-soluble fraction of CharSol C-10, was less effective, and L. monocytogenes survived in salmon steaks processed to an internal temperature of 166 degrees F (74.4 degrees C), the highest temperature tested with this liquid smoke. This study provides evidence that heat alone is not reliable for inactivation of L. monocytogenes during the hot-smoking process. The proper stage and duration of smoke application or proper composition and concentration of liquid smoke in combination with heat are critical for inactivation of the organism. RP Poysky, FT (reprint author), US DEPT COMMERCE,NW FISHERIES SCI CTR,NMFS,NOAA,UTILIZAT RES DIV,2725 MONTLAKE BLVD E,SEATTLE,WA 98112, USA. NR 38 TC 28 Z9 29 U1 1 U2 7 PU INT ASSOC MILK FOOD ENVIRONMENTAL SANITARIANS, INC PI DES MOINES PA 6200 AURORA AVE SUITE 200W, DES MOINES, IA 50322-2838 SN 0362-028X J9 J FOOD PROTECT JI J. Food Prot. PD JUN PY 1997 VL 60 IS 6 BP 649 EP 654 PG 6 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA XE592 UT WOS:A1997XE59200009 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article RP Coffey, HE (reprint author), NOAA,WORLD DATA CTR SOLAR TERR PHYS A,BOULDER,CO 80302, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1997 VL 102 IS A6 BP 11473 EP 11474 DI 10.1029/97JA01295 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XD974 UT WOS:A1997XD97400020 ER PT J AU Hwang, CS Vaudin, MD Stauf, GT AF Hwang, CS Vaudin, MD Stauf, GT TI Influence of substrate annealing on the epitaxial growth of BaTiO3 thin films by metal-organic chemical vapor deposition SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SURFACES; MGO AB BaTiO3 thin films were deposited by metal-organic chemical vapor deposition at 840 degrees C on two differently treated (100) MgO single crystal substrates, One MgO substrate was only mechanically polished and the other substrate was polished and then annealed at 1100 degrees C for 4 h in oxygen, Observation by transmission electron microscopy showed that the BaTiO3 thin film deposited on the unannealed substrate was fine-grained and that the whole film was epitaxial (100) in nature, In contrast, the film deposited on the annealed substrate consisted of large, (100)-oriented, epitaxial grains within which were distributed (110)-oriented grains with random in-plane orientations. These differences in BaTiO3 films deposited on differently treated substrates are discussed with reference to the surface structure of the MgO substrate and nucleation kinetics of BaTiO3 thin films on MgO. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. ADV TECHNOL MAT,DANBURY,CT 06810. RI Hwang, Cheol Seong/C-8568-2009 NR 16 TC 5 Z9 5 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1997 VL 12 IS 6 BP 1625 EP 1633 DI 10.1557/JMR.1997.0222 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA XC344 UT WOS:A1997XC34400030 ER PT J AU Domenech, JL Flaud, JM Fraser, GT Andrews, AM Lafferty, WJ Watson, PL AF Domenech, JL Flaud, JM Fraser, GT Andrews, AM Lafferty, WJ Watson, PL TI Infrared diode-laser molecular-beam spectrum of the nu(2) band of chlorine nitrate at 1293 cm(-1) SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID SPECTROSCOPY; CIONO2 AB The nu(2) band of chlorine nitrate (ClONO2) near 1293 cm(-1) has been measured in a molecular beam with a diode-laser spectrometer. The low rotational temperature of the molecular beam, similar to 23 K, simplifies the spectrum allowing essentially complete assignment of the Cl-35 and Cl-37 lines. An nib hybrid band is observed with the a-type transition moment being approximately a factor of 2 larger than the Lt-type transition moment. An inverted shift of the band origins is found with the Cl-37 band origin blue shifted From the Cl-35 by +0.37 cm(-1). This isotopic shift is attributed to an unidentified anharmonic resonance. Precise spectroscopic constants for the bands of each isotopic species are determined to allow future simulations for modeling atmospheric transmission and for remote sensing applications. (C) 1997 Academic Press. C1 UNIV PARIS 06,CNRS,LAB PHYS MOL & APPLICAT,F-75252 PARIS 05,FRANCE. NATL INST STAND & TECHNOL,DIV MOL PHYS,GAITHERSBURG,MD 20899. DUPONT CO INC,CENT RES & DEV,EXPT STN E328314,WILMINGTON,DE 19880. RP Domenech, JL (reprint author), CSIC,INST ESTRUCTURA MAT,SERRANO 119,E-28006 MADRID,SPAIN. RI Domenech, Jose/F-5561-2013 OI Domenech, Jose/0000-0001-8629-2566 NR 13 TC 13 Z9 13 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUN PY 1997 VL 183 IS 2 BP 228 EP 233 DI 10.1006/jmsp.1997.7260 PG 6 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA XE286 UT WOS:A1997XE28600004 ER PT J AU Chance, KV Park, K Evenson, KM Zink, LR Stroh, F Fink, EH Ramsay, DA AF Chance, KV Park, K Evenson, KM Zink, LR Stroh, F Fink, EH Ramsay, DA TI Improved molecular constants for the ground state of HO2 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article C1 UNIV OREGON, DEPT PHYS, EUGENE, OR 97403 USA. NATL INST STAND & TECHNOL, BOULDER, CO 80303 USA. NOAA, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80303 USA. UNIV COLORADO, BOULDER, CO 80303 USA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, INST STRATOSPHER CHEM, D-52425 JULICH, GERMANY. BERG UNIV GESAMTHSCH WUPPERTAL, PHYS CHEM FACHBEREICH 9, D-42097 WUPPERTAL, GERMANY. NATL RES COUNCIL CANADA, STEACIE INST MOL SCI, OTTAWA, ON K1A 0R6, CANADA. RP Chance, KV (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS, 60 GARDEN ST, CAMBRIDGE, MA 02138 USA. RI Stroh, Fred/A-6505-2009 OI Stroh, Fred/0000-0002-4492-2977 NR 2 TC 18 Z9 18 U1 1 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE 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 JUN PY 1997 VL 183 IS 2 BP 418 EP 418 DI 10.1006/jmsp.1997.7282 PG 1 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA XE286 UT WOS:A1997XE28600025 ER PT J AU Hallberg, R AF Hallberg, R TI Localized coupling between surface and bottom-intensified flow over topography SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID DRIVEN CIRCULATION; STRATIFIED OCEAN; ROSSBY WAVES; SPIN-UP; BASIN AB Substantial bottom topography in a basin with planetary vorticity gradients strongly affects the vertical structure of the linear topographic and planetary Rossby waves that spin up the ocean circulation. There is no barotropic mode with large amplitude topography and stratification. It is shown that the lowest frequency two-layer quasigeostrophic waves that exist with stratification, planetary vorticity gradients, and large-amplitude bottom topography are more strongly concentrated in the vertical than Burger number 1 scaling would indicate (for most orientations of the wavevector) except where the bottom slope is nearly meridional. This concentration increases with decreasing frequency. Ray tracing in an ocean basin suggests that the two layers are linearly coupled in regions with parallel or antiparallel topographic and planetary vorticity gradients, but elsewhere small amplitude motion in the two layers is largely independent. Continuity within isopycnal layers implies that most of the circulation remains within isopycnal layers, even in the regions of linear coupling. The strength of surface(bottom)-intensified flow driven by coupling to bottom(surface)-intensified flow is approximately twice as strong as the surface(bottom) projection of the bottom(surface)-intensified flow. Primitive equation simulations concur with the quasigeostrophic results and indicate that the localized linear coupling between surface-and bottom-intensified flow pertains to a continuous stratification. C1 NOAA,GEOPHYS FLUID DYNAM LAB,PRINCETON,NJ 08542. RP Hallberg, R (reprint author), PRINCETON UNIV,GEOPHYS FLUID DYNAM LAB,FORRESTAL CAMPUS,US ROUTE 1,POB 308,PRINCETON,NJ 08542, USA. NR 20 TC 23 Z9 25 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUN PY 1997 VL 27 IS 6 BP 977 EP 998 DI 10.1175/1520-0485(1997)027<0977:LCBSAB>2.0.CO;2 PG 22 WC Oceanography SC Oceanography GA XR046 UT WOS:A1997XR04600009 ER PT J AU Hare, JE Hara, T Edson, JB Wilczak, JM AF Hare, JE Hara, T Edson, JB Wilczak, JM TI A similarity analysis of the structure of airflow over surface waves SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID TURBULENT BOUNDARY-LAYER; PROGRESSIVE WATER-WAVE; PRESSURE-FLUCTUATIONS; WIND STRESS; AIR-FLOW; BREAKING; FIELD; PROBE AB Previous field investigations of the wave-induced pressure field have focused on determination of the momentum input from wind to the surface waves. This is useful for the estimation of wave growth rate and, in particular, the wave growth parameter p. Due to the difficult nature of experimental study of airflow very close to the wave surface, it has been necessary to extrapolate elevated measurements of the wave-induced pressure field to the surface. This practice may be incorrect without adequate knowledge of the complex vertical structure of the pressure field. In addition, the wave-induced pressure and velocity fields are coupled to the near-surface turbulence. Hence, understanding the nature of the wave-induced how fields is critical for modeling of the nearsurface wind and wave fields. Utilizing a simple similarity hypothesis, detailed vertical structure of the wave-induced pressure and velocity components is examined. Results of this analysis are presented using data obtained in the spring and fall of 1994 during the Riso Air-Sea Experiment program. These results demonstrate that, when compared to theory, simple extrapolation of measurements of the wave-induced pressure field from a fixed height above the surface may contribute to the uncertainty of measured growth rates. In addition, it is demonstrated that an analogous similarity relationship for the wave-induced vertical velocity field yields results that are consistent with previous laboratory studies. C1 PENN STATE UNIV,DEPT METEOROL,UNIVERSITY PK,PA 16802. UNIV RHODE ISL,GRAD SCH OCEANOG,NARRAGANSETT,RI 02882. WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543. RP Hare, JE (reprint author), NOAA,ENVIRONM RES LAB,ETL,MAIL CODE R-E-ET7,325 BROADWAY,BOULDER,CO 80303, USA. RI Hara, Tetsu/G-9779-2011 NR 48 TC 27 Z9 28 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUN PY 1997 VL 27 IS 6 BP 1018 EP 1037 DI 10.1175/1520-0485(1997)027<1018:ASAOTS>2.0.CO;2 PG 20 WC Oceanography SC Oceanography GA XR046 UT WOS:A1997XR04600011 ER PT J AU Lee, A McKenna, GB AF Lee, A McKenna, GB TI Anomalous aging in two-phase systems: Creep and stress relaxation differences in rubber-toughened epoxies SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE creep compliance; physical aging; rubber-toughened epoxies; stress relaxation; superposition; two-phase materials ID POLYMER-MATRIX COMPOSITES; SEMI-CRYSTALLINE POLYMERS; LONG-TERM CREEP; MECHANICAL-BEHAVIOR; SEMICRYSTALLINE POLYMERS; COMPLEX MODULI AB From time-aging time superposition principles, similar to time-temperature superposition, one would expect similar shifting or superposition behaviors for both creep and stress relaxation responses. In particular, for isotropic homogeneous systems, in the linear viscoelastic regime, consideration of superposition in rheology by Markowitz(1) or the discussion by Ferry(2) from the Kramers-Kronig relation would seem to demand that creep and stress relaxation shift in the same way. Here we report on results from creep and stress relaxation measurements in two-phase, rubber-toughened epoxies that exhibit Boltzman additivity of creep or relaxation behaviors and follow the time-aging time superposition behavior in creep, but not in stress relaxation. While the lack of superposition in stress relaxation is, perhaps, not surprising, the finding that the creep responses at different aging times superimpose while the stress relaxation responses do not, presents an anomalous behavior that has not been previously reported. In addition, our findings show that the stress relaxation responses show short time ''softening'' upon aging. Possible reasons for the anomalous behaviors are briefly considered. (C) 1997 John Wiley & Sons, Inc. C1 NIST,DIV POLYMERS,GAITHERSBURG,MD 20899. MICHIGAN STATE UNIV,DEPT MECH & MAT SCI,E LANSING,MI 48824. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 30 TC 23 Z9 23 U1 1 U2 10 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD JUN PY 1997 VL 35 IS 8 BP 1167 EP 1174 DI 10.1002/(SICI)1099-0488(199706)35:8<1167::AID-POLB1>3.0.CO;2-R PG 8 WC Polymer Science SC Polymer Science GA WU851 UT WOS:A1997WU85100001 ER PT J AU Lund, JAK Barnett, HJ Hatfield, CL Gauglitz, EJ Wekell, JC Rasco, B AF Lund, JAK Barnett, HJ Hatfield, CL Gauglitz, EJ Wekell, JC Rasco, B TI Domoic acid uptake and depuration in Dungeness crab (Cancer magister Dana 1852) SO JOURNAL OF SHELLFISH RESEARCH LA English DT Article DE domoic acid; Dungeness crab; cancer magister; razor clams; Siliqua patula; amnesic shellfish poisoning ID MUSSELS MYTILUS-EDULIS; PRINCE-EDWARD-ISLAND; SILIQUA-PATULA DIXON; PSEUDONITZSCHIA-AUSTRALIS; NITZSCHIA-PUNGENS; RAZOR CLAMS; AMINO-ACID; SHELLFISH; BACILLARIOPHYCEAE; OUTBREAK AB The patent marine neurotoxin domoic acid (DA) was detected in razor clams and Dungeness crabs on the Pacific Coast of the United States in 1991, resulting in temporary closures of these fisheries. Closures protect the health of human consumers of clams and crabs but impose significant economic losses to the communities that are dependent on these fisheries. Widespread closures, and in the case of the clams long-lasting ones, were necessary risk management strategies because our knowledge of DA uptake and movement through the food web is very limited. In order to resolve some of these issues and provide health managers with better information concerning this toxin, experiments were conducted on the accumulation and fate of DA in Dungeness crabs. Such information could provide enhanced safety, permit more efficient closures, and lessen the economic effect of future outbreaks. In the first study, razor clams, containing known concentrations of DA, were fed to Dungeness crabs for 5 days to determine the uptake of the toxin by the crabs. Twenty-four hours after the crabs ingested an initial 960 mu g of toxin, 260 mu g of DA (27%) was found in the hepatopancreas (HP) of the crabs. At the end of 6 days, 68% (2,850 mu g), from an accumulated 4,220 mu g of ingested toxin, was present in the HP. DA was never found in the hemolymph or edible muscle of crabs in this experiment, but DA was found in the feces, indicating a route of depuration. The second study examined the depuration of DA by crabs under fed and starved conditions. Crabs fed DA-contaminated clams for 4 days achieved an average concentration of 69.5 mu g of DA/g of HP. After 7 days, crabs that were fed toxin-free clams three times per week showed a 38% reduction in DA concentration, to 43.4 mu g of DA/g, whereas the average toxin concentration in the HP of crabs that were starved was reduced by only 4%, to 66.9 mu g of DA/g. In the last sampling, taken at 21 days, the concentration of DA in the HP of fed crabs decreased by 89% of the initial DA concentration to 7.6 mu g of DA/g, but that of the starved crabs decreased by only 57%, to 29.7 mu g of DA/g. Differences in mean concentrations between starved and fed crabs at 7, 14, and 21 days were significant. Additional measurements at 21 days showed the average weight of a starved crab's HP was only 53% of the fed crab's HP (25.7 vs. 48.7g). Although the mean weight of the starved crabs (770 g) was greater than that of the fed crabs (730 g), the difference was not significant. C1 UNIV WASHINGTON, INST FOOD SCI & TECHNOL, SCH FISHERIES, SEATTLE, WA 98105 USA. RP Lund, JAK (reprint author), NOAA, NATL MARINE FISHERIES SERV, NW FISHERIES SCI CTR, US DEPT COMMERCE, UTILIZAT RES DIV, SEATTLE, WA 98112 USA. NR 34 TC 14 Z9 14 U1 1 U2 6 PU NATL SHELLFISHERIES ASSOC PI GROTON PA C/O DR. SANDRA E. SHUMWAY, UNIV CONNECTICUT, 1080 SHENNECOSSETT RD, GROTON, CT 06340 USA SN 0730-8000 J9 J SHELLFISH RES JI J. Shellfish Res. PD JUN PY 1997 VL 16 IS 1 BP 225 EP 231 PG 7 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XM072 UT WOS:A1997XM07200032 ER PT J AU Grey, IE Roth, RS Balmer, ML AF Grey, IE Roth, RS Balmer, ML TI The crystal structure of Cs2TiSi6O15 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID TITANOSILICATE; CESIUM AB Crystals of a new titanosilicate phase, Cs2TiSi6O15, were grown from a cesium vanadate flux. The compound has monoclinic symmetry, space group C2/c, with a 13.386(5), b = 7.423(3), c = 15.134(5) Angstrom = beta = 107.71(3)degrees, Z = 4. The crystal structure was solved using single crystal X-ray data (MoK alpha radition) and refined to R(F) = 0.039 for 1874 unique reflections. In the structure, isolated titanium-centred octahedra and silica-centred tetrahedra share all corners to form an open framework structure containing large cavities in which the cesium ions are located. Each cavity is bound by three 5-rings, two 6-rings, and two 8-rings. The cavities are linked via the 8-rings into channels parallel to [101]. The cesium ions occur in pairs along the channels, separated by 3.765(2) Angstrom. (C) 1997 Academic Press. C1 NIST, GAITHERSBURG, MD 20899 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP Grey, IE (reprint author), CSIRO, DIV MINERALS, MELBOURNE, VIC, AUSTRALIA. NR 20 TC 13 Z9 13 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD JUN PY 1997 VL 131 IS 1 BP 38 EP 42 DI 10.1006/jssc.1997.7298 PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA XL406 UT WOS:A1997XL40600005 ER PT J AU Podobedov, VB Rice, JP Weber, A Drew, HD AF Podobedov, VB Rice, JP Weber, A Drew, HD TI Raman scattering from single crystal YBa2Cu3O7-delta in a magnetic field SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article DE YBCO; Raman scattering; magnetic field ID HIGH-TC SUPERCONDUCTORS; GAP; VORTEX AB A magneto-Raman study of a YBa2Cu3O7-delta single crystal (T-c=92 K) was carried out at a resolution of 2 cm(-1) over the temperature range 5-125 K. At temperatures below T-c we observed a slight narrowing of the 340 cm(-1) Raman mode in a magnetic field of 5.15 T directed parallel to the c-axis of the crystal. The observed magneto-temperature dependences of the Raman continuum intensity measured in the low-frequency region, at ca. 40 cm(-1), indicate contributions of electronic excitations arising from a pair-breaking process. Within the experimental uncertainty, the Raman intensity of the high-frequency continuum was observed to be independent of the magnetic field strength. C1 UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. RUSSIAN ACAD SCI,INST SPECT,TROITSK 142093,MOSCOW REGION,RUSSIA. RP Podobedov, VB (reprint author), NIST,OPT TECHNOL DIV,GAITHERSBURG,MD 20899, USA. NR 24 TC 4 Z9 4 U1 0 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD JUN PY 1997 VL 10 IS 3 BP 205 EP 209 DI 10.1007/BF02770552 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA XQ501 UT WOS:A1997XQ50100005 ER PT J AU Weickmann, KM Kiladis, GN Sardeshmukh, PD AF Weickmann, KM Kiladis, GN Sardeshmukh, PD TI The dynamics of intraseasonal atmospheric angular momentum oscillations SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MADDEN-JULIAN OSCILLATION; CIRCULATION ANOMALIES; TROPICAL PACIFIC; BALANCE; LENGTH; CYCLE; EARTH; CONVECTION; TORQUES; PERIOD AB The global and zonal atmospheric angular momentum (AAM) budget is computed from seven years of National Centers for Environmental Prediction data and a composite budget of intraseasonal (30-70 day) variations during northern winter is constructed. Regressions on the global AAM tendency are used to produce maps of outgoing longwave radiation, 200-hPa wind, surface stress, and sea level pressure during the composite AAM cycle. The primary synoptic features and surface torques that contribute to the AAM changes are described. In the global budget, the friction and mountain torques contribute about equally to the AAM tendency. The friction torque peaks in phase with subtropical surface easterly wind anomalies in both hemispheres. The mountain torque peaks when anomalies in the midlatitude Northern Hemisphere and subtropical Southern Hemisphere are weak but of the same sign. The picture is different for the zonal mean budget, in which the meridional convergence of the northward relative angular momentum transport and the friction torque are the dominant terms. During the global AAM cycle, zonal AAM anomalies move poleward from the equator to the subtropics primarily in response to momentum transports. These transports are associated with the spatial covariance of the filtered (30-70 day) perturbations with the climatological upper-tropospheric flow. The zonally asymmetric portion of these perturbations develop when convection begins over the Indian Ocean and maximize when convection weakens over the western Pacific Ocean, The 30-70-day zonal mean friction torque results from 1) the surface winds induced by the upper-tropospheric momentum sources and sinks and 2) the direct surface wind response to warm pool convection anomalies. The signal in relative AAM is complemented by one in ''Earth'' AAM associated with meridional redistributions of atmospheric mass. This meridional redistribution occurs preferentially over the Asian land mass and is linked with the 30-70-day eastward moving convective signal. It is preceded by a surface Kelvin-like wave in the equatorial Pacific atmosphere that propagates eastward from the western Pacific region to the South American topography and then moves poleward as an edge wave along the Andes. This produces a mountain torque on the Andes, which also causes the regional and global AAM to change. C1 NOAA,ENVIRONM RES LAB,AERON LAB,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Weickmann, KM (reprint author), NOAA,ERL,CLIMATE DIAGNOST CTR,325 BROADWAY,BOULDER,CO 80303, USA. NR 37 TC 67 Z9 70 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 1 PY 1997 VL 54 IS 11 BP 1445 EP 1461 DI 10.1175/1520-0469(1997)054<1445:TDOIAA>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XC335 UT WOS:A1997XC33500004 ER PT J AU Ohno, Y Lindemann, M Sauter, G AF Ohno, Y Lindemann, M Sauter, G TI Analysis of integrating sphere errors for lamps having different angular intensity distributions SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Article ID SCALE; NIST AB An experiment has been conducted, as a collaboration of the National Institute of Standards and Technology and Physikalisch-Technische Bundesanstalt, to evaluate errors in luminous flux measurements using an integrating sphere for lamps having different angular luminous intensity distributions. Incandescent lamps of seven different types, each having different filament structure and bulb materials were used. Each test lamp was equipped with either a bi-post base or a special mark to allow precise alignment for luminous intensity measurement. The total luminous flux of each lamp was measured using a 2 m integrating sphere at NIST and a three-axis goniophotometer at PTB. The luminous intensity of each lamp in a specified direction was also measured at both laboratories. The ratios of the total luminous flux and the luminous intensity are evaluated so that any possible differences in national realizations of the candela are canceled out. The integrating sphere errors are also obtained theoretically from the goniophotometric data of each lamp and the spatial nonuniformity of the sphere responsivity measured with a rotating beam lamp. The deviations of the integrating sphere measurements, as compared with the goniophotometric results, for all the test lamps are found to be within +/- 0.3 percent, which is within the estimated uncertainties of the measurements, and also in good agreement with the theoretical results. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Ohno, Y (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 5 TC 5 Z9 5 U1 1 U2 4 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD SUM PY 1997 VL 26 IS 2 BP 107 EP + PG 7 WC Optics SC Optics GA ZC938 UT WOS:000072634100052 ER PT J AU Reader, J Acquista, N AF Reader, J Acquista, N TI Long-wavelength transitions and improved energy levels of triply ionized zirconium (Zr IV) SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article AB Fourteen new spectral lines of Zr IV lying between 3200 and 4600 Angstrom were observed with a sliding spark discharge and a 10.7-m normal-incidence spectrograph. The lines were classified as transitions between highly excited energy levels of this ion. The measured wavelengths provide improved values for the known energy levels as well as a value for the previously unknown 6h H-2 term. Wavelengths with standard uncertainties varying from +/-0.0005 to +/-0.0018 Angstrom were determined from the optimized level values for a group of lines between 445 and 1291 Angstrom. An improved ionization energy was determined as 277 602.8 +/- 0.5 cm(-1) (34.41837 +/- 0.00006 eV). (C) 1997 Optical Society of America. RP Reader, J (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 6 TC 6 Z9 6 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUN PY 1997 VL 14 IS 6 BP 1328 EP 1330 DI 10.1364/JOSAB.14.001328 PG 3 WC Optics SC Optics GA XC639 UT WOS:A1997XC63900009 ER PT J AU Chapman, PM Anderson, B Carr, S Engle, V Green, R Hameedi, J Harmon, M Haverland, P Hyland, J Ingersoll, C Long, E Rodgers, J Salazar, M Sibley, PK Smith, PJ Swartz, RC Thompson, B Windom, H AF Chapman, PM Anderson, B Carr, S Engle, V Green, R Hameedi, J Harmon, M Haverland, P Hyland, J Ingersoll, C Long, E Rodgers, J Salazar, M Sibley, PK Smith, PJ Swartz, RC Thompson, B Windom, H TI General guidelines for using the sediment quality triad SO MARINE POLLUTION BULLETIN LA English DT Editorial Material ID INFAUNAL COMMUNITY COMPOSITION; SAN-FRANCISCO BAY; TOXICITY; CONTAMINATION C1 UNIV CALIF, INST MARINE SCI, MONTEREY, CA 93940 USA. TEXAS A&M UNIV, USGS BRD, CTR COASTAL STUDIES, CORPUS CHRISTI, TX 78412 USA. USGS BRD, GULF BREEZE, FL 32561 USA. UNIV WESTERN ONTARIO, DEPT ZOOL, LONDON, ON N6A 5B7, CANADA. NOAA, NOS, ORCA2, SILVER SPRING, MD 20910 USA. USGS, MIDWEST SCI CTR, COLUMBIA, MO 65201 USA. NOAA, NOS, CHARLESTON, SC 29422 USA. NOAA, ORCA, CMBAD, SEATTLE, WA 98115 USA. UNIV MISSISSIPPI, DEPT BIOL, UNIVERSITY, MS 38677 USA. APPL BIOMONITORING, KIRKLAND, WA 98034 USA. US EPA, MID OCEAN ECOL DIV, DULUTH, MN 55803 USA. UNIV MARYLAND, DEPT MATH, COLLEGE PK, MD 20742 USA. US EPA, NEWPORT, OR 97365 USA. SAN FRANCISCO ESTUARY INST, RICHMOND, CA 94804 USA. SKIDAWAY INST OCEANOG, SAVANNAH, GA 31411 USA. RP EVS CONSULTANTS LTD, 195 PEMBERTON AVE, N VANCOUVER, BC V7P 2R4, CANADA. NR 21 TC 58 Z9 65 U1 1 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD JUN PY 1997 VL 34 IS 6 BP 368 EP 372 DI 10.1016/S0025-326X(96)00138-5 PG 5 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA XR026 UT WOS:A1997XR02600011 ER PT J AU Long, ER Wilson, CJ AF Long, ER Wilson, CJ TI On the identification of toxic hot spots using measures of the sediment quality triad SO MARINE POLLUTION BULLETIN LA English DT Editorial Material ID INFAUNAL COMMUNITY COMPOSITION; CONTAMINATION C1 CALIF STATE WATER RESOURCES CONTROL BOARD, SACRAMENTO, CA 94244 USA. RP NOAA, OFF OCEAN RESOURCES CONSERVAT & ASSESSMENT, 7600 SAND PT WAY NE, SEATTLE, WA 98115 USA. NR 5 TC 16 Z9 18 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD JUN PY 1997 VL 34 IS 6 BP 373 EP 374 DI 10.1016/S0025-326X(97)00150-1 PG 2 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA XR026 UT WOS:A1997XR02600012 ER PT J AU Yan, XH ClementeColon, P Pichel, W AF Yan, XH ClementeColon, P Pichel, W TI The Maximum Similarity Shape Matching (MSSM) feature tracking method applied to an oil spill observed in SAR imagery SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article ID SATELLITE AB In this study, the Maximum Similarity Shape Matching (MSSM) method was applied to a pair of airborne SAR images and two pairs of spaceborne SAR images in order to observe the small scale features of an oil spill. A frontal region of the Gulf Stream was chosen as a test case of the technique on airborne SAR imagery. A spill off the coast of Wales, UK, was observed using spaceborne RADARSAT, ERS-1 AND ERS-2 SAR images. The data detected the persistence of slick features associated with the Sea Empress tanker massive oil spill, and showed the evolution of these features from February 22 to February 26, 1996. The MSSM method was applied to the ERS-1 and ERS-2 images. Drift speeds as high as 11 cm/s were calculated. Deformation of the slick features was also evident throughout the five day period. The result of the investigation revealed the trajectory of this particular oil spill, and also demonstrated the possible future application of this method to analysis of SAR imagery, in general, and to oil spill monitoring, in particular. C1 NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,WASHINGTON,DC 20233. RP Yan, XH (reprint author), UNIV DELAWARE,GRAD COLL MARINE STUDIES,CTR REMOTE SENSING,NEWARK,DE 19716, USA. RI Clemente-Colon, Pablo/F-5581-2010; Pichel, William/F-5619-2010 OI Pichel, William/0000-0001-6332-0149 NR 21 TC 2 Z9 2 U1 0 U2 4 PU MARINE TECHNOLOGY SOC INC PI WASHINGTON PA C/O I CLAYION MATTHEWS, 1828 L ST, NW, 9TH FL, WASHINGTON, DC 20036 SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD SUM PY 1997 VL 31 IS 2 BP 8 EP 14 PG 7 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA XT891 UT WOS:A1997XT89100002 ER PT J AU Watson, KL AF Watson, KL TI Oceanic and atmospheric measurements from offshore platforms SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Editorial Material RP Watson, KL (reprint author), NOAA,OFF GLOBAL PROGRAMS,SILVER SPRING,MD 20910, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MARINE TECHNOLOGY SOC INC PI WASHINGTON PA C/O I CLAYION MATTHEWS, 1828 L ST, NW, 9TH FL, WASHINGTON, DC 20036 SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD SUM PY 1997 VL 31 IS 2 BP 69 EP 71 PG 3 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA XT891 UT WOS:A1997XT89100010 ER PT J AU Cahn, JW AF Cahn, JW TI Comment on: Reassessing the nucleation and growth kinetics of solid state phase transformations SO MATERIALS RESEARCH INNOVATIONS LA English DT Editorial Material C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Cahn, JW (reprint author), NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 15 TC 2 Z9 2 U1 0 U2 8 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1432-8917 J9 MATER RES INNOV JI Mater. Res. Innov. PD JUN PY 1997 VL 1 IS 1 BP 64 EP 65 DI 10.1007/s100190050020 PG 2 WC Materials Science, Multidisciplinary SC Materials Science GA YX890 UT WOS:000072090600011 ER PT J AU Hurley, DC Fortunko, CM AF Hurley, DC Fortunko, CM TI Determination of the nonlinear ultrasonic parameter beta using a Michelson interferometer SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article ID SOLIDS AB We describe an accurate optical technique for determining the nonlinear ultrasonic parameter beta. Our technique uses a path-stabilized Michelson laser interferometer, in contrast to more conventional methods which use piezoelectric or capacitive detectors. Features include high spatial resolution (typically 20 mu m), flat bandpass response over a wide range (>30 MHz) and simple self-calibration. We demonstrate the technique using a fused silica disc 19.15 mm thick and a fundamental frequency of 10 MHz. For comparison, beta was also obtained for the same specimen using capacitive and piezoelectric detectors, Errors and correction factors for all three methods are discussed; in particular, we note the importance of including ultrasonic diffraction effects. When such corrections are applied, we obtain the following results: \beta(interf)\ = 11.4 +/- 0.4, \beta(capac)\ = 12.0 +/- 0.4 and \beta(piezo)\ = 10.2 +/- 0.5. These values are in reasonable agreement with each other as well as with published values of \beta\ = 11-14. RP NATL INST STAND & TECHNOL, 325 BROADWAY, BOULDER, CO 80303 USA. NR 25 TC 30 Z9 38 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD JUN PY 1997 VL 8 IS 6 BP 634 EP 642 DI 10.1088/0957-0233/8/6/009 PG 9 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA XE253 UT WOS:A1997XE25300009 ER PT J AU Ziegler, CL Lee, TJ Pielke, RA AF Ziegler, CL Lee, TJ Pielke, RA TI Convective initiation at the dryline: A modeling study SO MONTHLY WEATHER REVIEW LA English DT Article ID SEVERE-STORM ENVIRONMENT; PLANETARY BOUNDARY-LAYER; LARGE-SCALE CONVERGENCE; ELEVATED MIXED LAYERS; SEVERE LOCAL STORMS; SEA-BREEZE FRONT; DEEP CONVECTION; SQUALL-LINE; NUMERICAL SIMULATIONS; SOIL-MOISTURE AB A nonhydrostatic, three-dimensional version of the Colorado State University Regional Atmospheric Modeling System (CSU-RAMS) is used to deduce the processes responsible for the formation of drylines and the subsequent initiation of deep, moist dryline convection. A range of cumuliform cloud types are explicitly simulated along drylines on 15, 16, and 26 May 1991 in accordance with observations. In the simulations, narrow convergence bands along the dryline provide the lift to initiate deep moist convection. The thermally direct secondary convective boundary layer (CBL) circulations along the dryline are frontogenetic and solenoidally forced. Maximum updrafts reach 5 m s(-1) and the bands are 3-9 km wide and 10-100 km or more in length. The updrafts penetrate and are decelerated by the overlying stable air above the CBL, reaching depths of about 2000 m in the cases studied. Moisture convergence along the mesoscale updraft bands destabilizes the local sounding to deep convection, while simultaneously decreasing the CIN to zero where storms subsequently develop. The lapse rates of vapor mixing ratio and potential temperature in the mesoscale updrafts are rather small, indicating that increases of the lifted condensation level (LCL) and level of free convection (LFC) due to mixing following the parcel motion are also small. Simulated convective clouds of all modes, including shallow forced cumulus and storms, develop in regions where the CIN ranges from zero up to the older of the peak kinetic energy of the boundary layer updraft and moisture is sufficiently deep to permit water saturation to develop in the boundary layer. The findings suggest that classic cloud models may not adequately simulate the early development of dryline storms due to their use of thermal bubbles to initiate convection and their assumption of a horizontally homogeneous environment. In contrast, cautious optimism may be warranted in regard to operational numerical prediction of drylines and the threat of attendant deep convection with mesoscale models. C1 COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523. RP Ziegler, CL (reprint author), NATL SEVERE STORMS LAB,MESOSCALE RES & APPLICAT DIV,NOAA,1313 HALLEY CIRCLE,NORMAN,OK 73069, USA. RI Pielke, Roger/A-5015-2009 NR 97 TC 78 Z9 81 U1 1 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 1997 VL 125 IS 6 BP 1001 EP 1026 DI 10.1175/1520-0493(1997)125<1001:CIATDA>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XD651 UT WOS:A1997XD65100001 ER PT J AU Purser, RJ Leslie, LM AF Purser, RJ Leslie, LM TI High-order generalized Lorenz N-cycle schemes for semi-Lagrangian models employing second derivatives in time SO MONTHLY WEATHER REVIEW LA English DT Article ID INTEGRATION SCHEME; NUMERICAL-INTEGRATION; MULTIPLY-UPSTREAM; IMPLICIT; TRAJECTORIES; EQUATIONS AB Having recently demonstrated that significant enhancement of forecast accuracy in a semi-Lagrangian model results from the application of high-order time integration methods to the second-derivative form of the equations governing the trajectories, the authors here extend the range of available methods by introducing a class of what they call ''generalized Lorenz'' (GL) schemes. These explicit GL schemes, like Lorenz's ''N-cycle'' methods, which inspired them, achieve a high formal accuracy in time for linear systems at an economy of storage that is the theoretical optimum. They are shown to possess robustly stable and consistent semi-implicit modifications that allow the deepest (fastest) gravity waves to be created implicitly, so that integrations can proceed efficiently with time steps considerably longer than would be possible in an Eulerian framework. Tests of the GL methods are conducted using an ensemble of 360 forecast cases over the Australian region at high spatial resolution, verifying at 48 h against a control forecast employing time steps sufficiently short to render time truncation errors negligible. Compared with the performance of the best alternative semi-Lagrangian treatment of equivalent storage economy (a quasi-second-order generalized Adams-Bashforth method), our new GL methods produce significant improvements both in formal accuracy and in actual forecast skill. C1 GEN SCI CORP,LAUREL,MD. UNIV NEW S WALES,SYDNEY,NSW,AUSTRALIA. RP Purser, RJ (reprint author), NATL CTR ENVIRONM PREDICT,NOAA,W-NP2 WWB ROOM 207,WASHINGTON,DC 20233, USA. NR 26 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 1997 VL 125 IS 6 BP 1261 EP 1276 DI 10.1175/1520-0493(1997)125<1261:HOGLNC>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XD651 UT WOS:A1997XD65100014 ER PT J AU Bao, JW Errico, RM AF Bao, JW Errico, RM TI An adjoint examination of a nudging method for data assimilation SO MONTHLY WEATHER REVIEW LA English DT Article ID 4-DIMENSIONAL DATA ASSIMILATION; PLANETARY BOUNDARY-LAYER; AREA MESOSCALE MODEL; MONSOON REGION; INITIALIZATION; SENSITIVITY; PREDICTION; CYCLONE AB A regional adjoint modeling system is modified to determine the sensitivities of data assimilation and forecast results with respect to perturbations of the nudging fields and coefficients A generalized linear system is used to explain the sensitivities both mathematically and physically. A linearized shallow-water model is utilized to show that the dynamics determining the sensitivities can be well described in terms of the dynamics of geostrophic adjustment, with the added effects of dissipation and nudging terms. The purpose of the study is to reveal the dynamics responsible for the sensitivities of assimilated fields and forecasts to a given observed variable, and thus to gain insight into what kinds of information are most (or least) effectively assimilated by the nudging method. The results of the adjoint study reveal that the nudging terms contribute significantly to the prognostic tendencies, even if the values of the nudging coefficient are smaller than those commonly used. When either all dynamic fields or only wind fields are nudged, the assimilation result is much more sensitive to the analyzed data at a later time. The sensitivity of the variance of the difference between the assimilation result and the analyzed data at the final time within various bands of horizontal and vertical spatial scales shows that little scale interaction is evident in this study. The qualitative comparison of the sensitivity results for nudging only wind or temperature or both are apparently well explained by referring to results of a sensitivity analysis for a nudged, linear shallow-water model. The latter results-indicate that nudging high-frequency gravity waves toward an analysis that varies on a much slower timescale had little effect on the final assimilation fields, aside from damping. The same was not true for either rotational modes or slowly propagating inertial-gravitational modes. The sensitivity analysis of the shallow water model also explains why nudging temperature alone does not produce desirable results. All the results indicate that the advection is being overwhelmed by the nudging even when the value of the nudging coefficient is half as large as commonly used, but geostrophic and dissipative adjustment are acting effectively. For larger values of the nudging coefficients, the effects of advection are diminished more. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. RP UNIV COLORADO, NOAA, ETL, COOPERAT INST RES ENVIRONM SCI, 325 BROADWAY, BOULDER, CO 80303 USA. NR 37 TC 15 Z9 15 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 1997 VL 125 IS 6 BP 1355 EP 1373 DI 10.1175/1520-0493(1997)125<1355:AAEOAN>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XD651 UT WOS:A1997XD65100020 ER PT J AU Odashima, H Tachikawa, M Zink, LR Evenson, KM AF Odashima, H Tachikawa, M Zink, LR Evenson, KM TI Extension of tunable far-infrared spectroscopy to 7.9 THz SO OPTICS LETTERS LA English DT Article ID FREQUENCY MEASUREMENTS; TRANSITIONS; CONSTANTS; RADIATION; CO2-LASER; CLUSTERS; METHANOL; REGION; BAND AB We generated tunable far-infrared radiation by mixing CO2-laser, (NH3)-N-15-laser, and microwave radiations in a W-Co metal-insulator-metal diode. We used this far-infrared radiation to measure accurately the torsion-rotation transitions of CH3OH in the 6-8-THz region. C1 NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,BOULDER,CO 80303. RP Odashima, H (reprint author), TOYAMA UNIV,DEPT PHYS,GOFUKU 3190,TOYAMA 930,JAPAN. NR 22 TC 5 Z9 5 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 1 PY 1997 VL 22 IS 11 BP 822 EP 824 DI 10.1364/OL.22.000822 PG 3 WC Optics SC Optics GA XC137 UT WOS:A1997XC13700025 PM 18185674 ER PT J AU Lin, HL Peterson, LC Overpeck, JT Trumbore, SE Murray, DW AF Lin, HL Peterson, LC Overpeck, JT Trumbore, SE Murray, DW TI Late Quaternary climate change from delta O-18 records of multiple species of planktonic foraminifera: High-resolution records from the anoxic Cariaco Basin, Venezuela SO PALEOCEANOGRAPHY LA English DT Article ID DEEP-WATER FLUXES; ISOTOPIC COMPOSITION; SARGASSO SEA; ENVIRONMENTAL HISTORY; VERTICAL-DISTRIBUTION; LAST DEGLACIATION; SEASONAL-CHANGES; NORTH-ATLANTIC; LAKE VALENCIA; SOUTH-AMERICA AB Seasonal trade wind-induced upwelling along the southern margin of the Caribbean Sea occurs in response to the annual migration of the Intertropical Convergence Zone. Laminated, high deposition rate sediments of the Cariaco Basin, a small anoxic basin on the Venezuelan continental shelf, clearly record large changes in the past intensity of this upwelling. Because sediments of the Cariaco Basin are largely unbioturbated, they offer a natural opportunity to study the stable isotopic records of multiple planktonic foraminiferal taxa and to evaluate their sensitivity to both the modern hydrography and temporal changes in upwelling intensity and climate. Oxygen isotope data (delta(18)O) from four dominant foraminiferal taxa are presented for the time period covering the last 28 kyr. The delta(18)O data from Globigerina bulloides, after correction for nonequilibrium precipitation, are used as a monitor of sea surface conditions during the winter-spring upwelling season. The delta(18)O data from white Globigerinoides ruber are used as a measure of annual-average conditions in the near surface, while pink G. ruber data are consistent with use as an index of end-member conditions during the summer-fall nonupwelling season. Data from the deeper dwelling Neogloboquadrina dutertrei yield information on conditions near the base of the local thermocline. During the last glacial, delta(18)O data from G. ruber and generally reduced interspecific differences indicate cooling of surface waters over the Cariaco Basin by up to 4 degrees C. This longer-term cooling does not appear to be related to changes in upwelling intensity along the coast but may instead reflect more regional cooling of the larger Caribbean. Superimposed on this pattern, between 12.6 and similar to 10 ka, is a convergence of delta(18)O data between G. bulloides and N. dutertrei, implying much stronger upwelling during the last deglaciation. This scenario is consistent with other evidence for high productivity at this time. At similar to 14 ka, a sharp delta(18)O depletion event observed in all taxa seems to have been produced by increased freshwater discharge to the southern Caribbean, suggesting either higher regional rainfall or the influence of glacial melting in the Andes. Minimum delta(18)O values of pink G. ruber around 6-7 ka record warmer summer sea surface temperatures and/or decreased salinity in the mid-Holocene. C1 BROWN UNIV,DEPT GEOL SCI,PROVIDENCE,RI 02912. NOAA,PALEOCLIMATOL PROGRAM,NATL GEOPHYS DATA CTR,BOULDER,CO 80303. UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MIAMI,FL 33149. UNIV CALIF IRVINE,DEPT EARTH SYST SCI,IRVINE,CA 92717. RI Trumbore, Susan/B-1948-2013 NR 85 TC 70 Z9 72 U1 1 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0883-8305 J9 PALEOCEANOGRAPHY JI Paleoceanography PD JUN PY 1997 VL 12 IS 3 BP 415 EP 427 DI 10.1029/97PA00230 PG 13 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA XB807 UT WOS:A1997XB80700006 ER PT J AU Bush, ABG Philander, SGH AF Bush, ABG Philander, SGH TI The late Cretaceous: Simulation with a coupled atmosphere-ocean general circulation model SO PALEOCEANOGRAPHY LA English DT Article ID SEASONAL CYCLE; PHANEROZOIC TIME; CLIMATE; CO2; SENSITIVITY; TEMPERATURE; VEGETATION; LATITUDE; HISTORY; WATER AB Results are presented for the climate of the late Cretaceous period (similar to 75-65 Ma) as simulated by a global climate model that is interactively coupled to a primitive equation global ocean model. Increased values of atmospheric CO2 and altered land surface albedos are invoked to produce the warm Cretaceous temperatures that have been proposed from biogeographic reconstructions. For comparison, a control simulation of the present climate is performed. The globally averaged atmospheric temperature in the Cretaceous simulation stabilizes after 20 years of integration at a value that is 4 degrees C greater than that of the present day. The lower troposphere in high latitudes contributes a majority of the globally averaged warming as a result of the elimination of the Antarctic and Greenland ice sheets. Nevertheless, equatorial surface temperatures are raised by similar to 5 degrees C above those of the control simulation and offset somewhat the reduction in near-surface baroclinicity caused by the absence of the high-latitude ice sheets. In the Cretaceous simulation, global precipitation is approximately 10% greater than in the present day, with the only region of reduced precipitation occurring beneath the south Eurasian monsoon. Additionally, the amplitude of the seasonal cycle in near-surface temperatures is smaller in the Cretaceous and, in conjunction with increased mean annual temperatures, precludes the presence of any year-round snow or ice in the simulation. In high latitudes, however, there are regions that seasonally drop below freezing. The temperatures in these regions are warmer than have been previously observed in atmosphere-only simulations as a result of poleward heat transport by the ocean's surface currents. C1 PRINCETON UNIV,PROGRAM ATMOSPHER & OCEAN SCI,PRINCETON,NJ 08544. NR 55 TC 55 Z9 59 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0883-8305 J9 PALEOCEANOGRAPHY JI Paleoceanography PD JUN PY 1997 VL 12 IS 3 BP 495 EP 516 DI 10.1029/97PA00721 PG 22 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA XB807 UT WOS:A1997XB80700011 ER PT J AU Elvidge, CD Baugh, KE Kihn, EA Kroehl, HW Davis, ER AF Elvidge, CD Baugh, KE Kihn, EA Kroehl, HW Davis, ER TI Mapping city lights with nighttime data from the DMSP operational linescan system SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article AB The Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) has a unique capability to detect low levels of visible and near-infrared (VNIR) radiance at night. With the OLS ''VIS'' band data, it is possible to detect clouds illuminated by moonlight, plus lights from cities, towns, industrial sites, gas flares, and ephemeral events such as fires and lightning illuminated clouds. This paper presents methods which have been developed for detecting and geolocating VNIR emission sources with nighttime DMSP-OLS data and the analysis of image time series to identify spatially stable emissions from cities, towns, and industrial sites. Results are presented for the United States. C1 NOAA,SOLAR TERRESTRIAL PHYS DIV,NATL GEOPHYS DATA CTR,BOULDER,CO 80303. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. RP Elvidge, CD (reprint author), UNIV NEVADA SYST,DESERT RES INST,RENO,NV 89506, USA. RI Elvidge, Christopher/C-3012-2009 NR 10 TC 316 Z9 340 U1 6 U2 66 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JUN PY 1997 VL 63 IS 6 BP 727 EP 734 PG 8 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA XC407 UT WOS:A1997XC40700009 ER PT J AU Altorfer, F Essmann, R AF Altorfer, F Essmann, R TI NH3 dynamics in Zn(NH3)(4)I-2 and Zn(NH3)(4)Br-2 investigated by incoherent quasielastic neutron scattering SO PHYSICA B LA English DT Article; Proceedings Paper CT 1st European Conference on Neutron Scattering (ECNS 96) CY OCT 08-11, 1996 CL INTERLAKEN, SWITZERLAND SP European Neutron Scattering Assoc, Paul Scherrer Inst, Villigen, Swiss Soc Neutron Scattering DE proton dynamics; diffusion; quasielastic scattering AB We report on studies of NH3 dynamics in Zn(NH3)(4)I-2 and Zn(NH3)(4)Br-2 by means of incoherent quasielastic neutron scattering in the temperature range from 150 to 300 K. Quasielastic experiments were carried out on the Fermi chopper time-of-flight spectrometer at NIST. The Lorentzian full-widths at half-maximum, f(w), of the quasielastic line follow an Arrhenius law and increase from 0.39 [0.25] meV at 150 K to 1.33 [0.80] meV at 300 K. We find an activation energy E-a for the NH3 reorientations of 32(1) and 30(3) meV for Zn(NH3)(4)I-2 and Zn(NH3)(4)Br-2, respectively. C1 NIST,GAITHERSBURG,MD 20899. UNIV MAINZ,FACHBEREICH CHEM & PHARM,D-55099 MAINZ,GERMANY. RP Altorfer, F (reprint author), UNIV MARYLAND,COLLEGE PK,MD 20742, USA. NR 3 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 1997 VL 234 BP 61 EP 63 DI 10.1016/S0921-4526(96)00879-4 PG 3 WC Physics, Condensed Matter SC Physics GA XG666 UT WOS:A1997XG66600025 ER PT J AU Bodeker, P Sonntag, P Schreyer, A Borchers, J Hamacher, K Kaiser, H Zabel, H AF Bodeker, P Sonntag, P Schreyer, A Borchers, J Hamacher, K Kaiser, H Zabel, H TI Spin density waves in epitaxial Fe/Cr films SO PHYSICA B LA English DT Article; Proceedings Paper CT 1st European Conference on Neutron Scattering (ECNS 96) CY OCT 08-11, 1996 CL INTERLAKEN, SWITZERLAND SP European Neutron Scattering Assoc, Paul Scherrer Inst, Villigen, Swiss Soc Neutron Scattering DE antiferromagnetism; proximity effects; spin density wave; thin films AB We have investigated proximity effects of Fe layers on the spin density waves (SDW) in thin epitaxial Cr[001] films with neutron scattering. Unlike in bulk Cr we observe a strong anisotropic occupation of the three possible SDWs. In pure Cr[001] films the SDWs exhibit an almost complete out-of-plane propagation with spins parallel to Q. With only 20 A Fe on top of these Cr films, the SDW becomes completely re-oriented with Q now propagating in the plane but the Cr-spins still point out of the plane. This implies that the Fe and Cr moments are oriented perpendicular to each other. C1 RUHR UNIV BOCHUM,INST EXPT PHYS FESTKORPERPHYS,D-44780 BOCHUM,GERMANY. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. UNIV MISSOURI,RES REACTOR,COLUMBIA,MO 65211. RI Zabel, Hartmut/C-1994-2009 NR 6 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 1997 VL 234 BP 464 EP 466 DI 10.1016/S0921-4526(96)01011-3 PG 3 WC Physics, Condensed Matter SC Physics GA XG666 UT WOS:A1997XG66600174 ER PT J AU Moudden, AH VasiliuDoloc, L Goukassov, A DeLeonGuevara, AM Pinsard, L Revcolevschi, A AF Moudden, AH VasiliuDoloc, L Goukassov, A DeLeonGuevara, AM Pinsard, L Revcolevschi, A TI Spin waves of lightly doped La1-xSrxMnO3 SO PHYSICA B LA English DT Article; Proceedings Paper CT 1st European Conference on Neutron Scattering (ECNS 96) CY OCT 08-11, 1996 CL INTERLAKEN, SWITZERLAND SP European Neutron Scattering Assoc, Paul Scherrer Inst, Villigen, Swiss Soc Neutron Scattering DE magnetoresistance; antiferromagnetism; spin waves AB Neutron scattering has been used to study the spin dynamics of the lightly doped La1-xSrxMnO3. As the dopant concentration increases from 0 to 0.09, the magnetic long-range order changes from a slightly to a strongly canted antiferromagnetic order, while the corresponding transition temperature is reduced from 140 to about 120 K. The spin waves show an anisotropic dispersion relation which can be described by a strong in-plane ferromagnetic coupling J(ab) and a weak inter-plane antiferromagnetic coupling J(c). The spin-wave dispersion exhibits a finite energy gap which decreases with the dopant concentration from about 2.5 meV for x = 0 to about 1.5 meV for x = 0.09. Furthermore, while the ferromagnetic in-plane coupling is slightly enhanced upon doping, the inter-plane antiferromagnetic coupling is strongly reduced, leading to a two-dimensional ferromagnetic system near the concentration x = 0.09. C1 NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. UNIV PARIS 11,CHIM SOLIDE LAB,F-91405 ORSAY,FRANCE. RP Moudden, AH (reprint author), CEA,CNRS,LAB LEON BRILLOUIN,F-91191 GIF SUR YVETTE,FRANCE. NR 8 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 1997 VL 234 BP 859 EP 860 DI 10.1016/S0921-4526(96)01132-5 PG 2 WC Physics, Condensed Matter SC Physics GA XG666 UT WOS:A1997XG66600321 ER PT J AU Swartzendruber, LJ Bennett, LH Vajda, F DellaTorre, E AF Swartzendruber, LJ Bennett, LH Vajda, F DellaTorre, E TI Relationship between the measurement of accommodation and after-effect SO PHYSICA B LA English DT Article; Proceedings Paper CT Workshop on Hysteresis Modeling and Micromagnetism CY MAY 20-22, 1996 CL GEORGE WASHINGTON UNIV, ASHBURN, VA HO GEORGE WASHINGTON UNIV DE hysteresis; after-effect accommodation; magnetic recording materials; remanent coercivity; Preisach model ID PARTICULATE SYSTEMS AB After-effect and accommodation were measured for two types of magnetic materials: nanoparticle pure iron material and a commercial gamma Fe2O3 recording material. The time scale of the observation was from about 10-1000 s. The after-effect was measured by rapidly changing the applied field from positive saturation to a fixed value, H, which was subsequently unchanged for the duration of the measurement. The after-effect was proportional to the logarithm of time. The accommodation was found to be proportional to the logarithm of the number of cycles, and hence also to the logarithm of time. For both samples, it was found that the after-effect curve with the greatest slope occurs at the value of H given by the remanent coercivity, H-ci, and not simply near the coercivity, H-c, as previously reported. This is attributed to the fact that, when measuring the time-dependence in the customary manner, a change in the interaction field also causes an accommodation-like drift in the magnetization. Using a physically derived accommodation model, it has been shown that the maximum accommodation minor loop field extrema have a small separation compared to the major loop width, then the after-effect and accommodation slopes are nearly identical and the two phenomena are then difficult to distinguish from each other. C1 GEORGE WASHINGTON UNIV,INST MAGNET RES,WASHINGTON,DC 20052. DIGITAL MEASUREMENTS SYST INC,BURLINGTON,MA 01803. RP Swartzendruber, LJ (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 8 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 1997 VL 233 IS 4 BP 324 EP 329 DI 10.1016/S0921-4526(97)00317-7 PG 6 WC Physics, Condensed Matter SC Physics GA XG665 UT WOS:A1997XG66500010 ER PT J AU Bennett, LH Donahue, MJ Shapiro, AJ Brown, HJ Gornakov, VS Nikitenko, VI AF Bennett, LH Donahue, MJ Shapiro, AJ Brown, HJ Gornakov, VS Nikitenko, VI TI Investigation of domain-wall formation and motion in magnetic multilayers SO PHYSICA B LA English DT Article; Proceedings Paper CT Workshop on Hysteresis Modeling and Micromagnetism CY MAY 20-22, 1996 CL GEORGE WASHINGTON UNIV, ASHBURN, VA HO GEORGE WASHINGTON UNIV DE magnetic multilayers; magnetization reversal process; antiferromagnetism; magnetic-optical detection; magnetic domains; spin-flop process; domain-wall motion ID INDICATOR AB The magnetization-reversal processes in two electrodeposited [Co64Ni31Cu5 2 nm/Cu](200) multilayers are investigated using an advanced magneto-optical indicator film (MOIF) technique together with SQUID and vector vibrating sample magnetometry. The non-magnetic Cu spacers are congruent to 1 nm thick in one specimen leading to predominantly antiferromagnetic exchange coupling between the ferromagnetic Co64Ni31Cu5 layers, and congruent to 3 nm in the other, with ferromagnetic coupling. The hysteresis loop of the ferromagnetic multilayer is conventional, indicating the stages of domain-wall formation, motion and saturation. Nucleation and movement of domain walls in different layers proceed in a partially uncorrelated manner, and are determined by defects near the surface edge and inside of the multilayer. As a result, the front of the magnetization reversal has a staggered configuration. The antiferromagnetic multilayer has an atypical loop, first with one susceptibility, then a step to a new value, then another susceptibility, and with non-symmetrical behavior about the field axis. Narrow and non-staggered domain-wall images in antiferromagnetically coupled layers are observed. The MOIF technique is used to provide a portrait of the vertical component of the magnetostatic field intensity, helping to elucidate the spin-flip and/or spin-flop processes which are apparently responsible for the hysteresis behavior. C1 NIST,GAITHERSBURG,MD 20899. RUSSIAN ACAD SCI,INST SOLID STATE PHYS,CHERNOGOLOVKA 142432,MOSCOW DISTRICT,RUSSIA. RP Bennett, LH (reprint author), GEORGE WASHINGTON UNIV,INST MAGNET RES,ASHBURN,VA 20147, USA. NR 6 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 1997 VL 233 IS 4 BP 356 EP 364 DI 10.1016/S0921-4526(97)00321-9 PG 9 WC Physics, Condensed Matter SC Physics GA XG665 UT WOS:A1997XG66500015 ER PT J AU Donahue, MJ McMichael, RD AF Donahue, MJ McMichael, RD TI Exchange energy representations in computational micromagnetics SO PHYSICA B-CONDENSED MATTER LA English DT Article DE micromagnetics; exchange energy; hysteresis ID DOMAIN-WALLS; PARTICLES; FILMS AB In order to solve Brown's equations, which describe a continuous medium, computational micromagnetic modeling requires a discrete representation of the magnetization M(r), and a discrete representation of the derivatives of M(r) must be chosen. This choice may be made through an explicit choice of interpolation or through the choice of numerical representation of Brown's equations. In this paper we describe some alternative representations of the exchange energy on a square 2-D grid, and test these representations through comparison with analytical results for magnetization spirals and with simulations testing vortex and domain wall mobility. RP Donahue, MJ (reprint author), NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. RI McMichael, Robert/J-8688-2012; OI McMichael, Robert/0000-0002-1372-664X NR 13 TC 72 Z9 72 U1 2 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 EI 1873-2135 J9 PHYSICA B JI Physica B PD JUN PY 1997 VL 233 IS 4 BP 272 EP 278 DI 10.1016/S0921-4526(97)00310-4 PG 7 WC Physics, Condensed Matter SC Physics GA XG665 UT WOS:A1997XG66500003 ER PT J AU Serpa, FG Morgan, CA Meyer, ES Gillaspy, JD Trabert, E Church, DA Takacs, E AF Serpa, FG Morgan, CA Meyer, ES Gillaspy, JD Trabert, E Church, DA Takacs, E TI Measurement of a magnetic-dipole transition probability in Xe32+ using an electron-beam ion trap SO PHYSICAL REVIEW A LA English DT Article ID HIGHLY-CHARGED IONS; STORAGE-RING; LIFETIME; EXCITATION AB The transition probability for the 3d(4) D-5(2) <-- D-5(3) magnetic-dipole transition in Ti-like Xe (Xe32+) has been measured using an electron-beam ion trap. The unusually weak dependence of the transition energy on nuclear charge Z, and the fact that the transition wavelength remains in the 320- to 400-nm range for 544p resonance. The complex spectra recorded by conventional electron spectroscopy are greatly simplified when recorded in coincidence with fluorescent x rays, allowing a more detailed analysis of the vacancy cascade process. The resulting coincidence spectra are compared with Hartree-Fock calculations, which include shake-up transitions in the resonant case. Small energy shifts of the coincident electron spectra are attributed to postcollision interaction with 1s photoelectrons. C1 ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. EPSRC,DARESBURY LAB,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. RP Arp, U (reprint author), NIST,DIV ELECTRON & OPT PHYS,GAITHERSBURG,MD 20899, USA. RI Arp, Uwe/C-2854-2009; OI Arp, Uwe/0000-0002-6468-9455 NR 67 TC 17 Z9 17 U1 0 U2 4 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 JUN PY 1997 VL 55 IS 6 BP 4273 EP 4284 DI 10.1103/PhysRevA.55.4273 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XE372 UT WOS:A1997XE37200045 ER PT J AU Ellinger, K Cooper, J AF Ellinger, K Cooper, J TI Many-particle effects in laser cooling of one-dimensional optical molasses SO PHYSICAL REVIEW A LA English DT Article ID 2 IDENTICAL ATOMS; RESONANCE FLUORESCENCE; RADIATION; SYSTEMS; FIELD; LIGHT; FORCE; TRAP AB We analyze the influence of long-range dipole-dipole interactions between atoms with Zeeman substructure on atomic polarization-gradient cooling at low laser power. The system we consider is a cloud of N atoms driven by two counterpropagating linear cross-polarized laser beams (lin perpendicular to lin configuration) on a 1/2-3/2 transition. In the semiclassical regime we derive analytical results for the change of the cooling force due to collisions and for the diffusion coefficient in the far-field approximation. For the energy regime where the center-of-mass motion is characterized by oscillations in the optical potentials, we estimate the effect of these far-field collisions on the motion-induced sideband structure of the resonance fluorescence spectrum by using a white-noise approximation for the background light field. This gives a qualitative signature of the heating mechanism in such systems. C1 UNIV COLORADO, NATL INST STAND & TECHNOL, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. RP UNIV INNSBRUCK, INST THEORET PHYS, TECHNIKERSTR 25, A-6020 INNSBRUCK, AUSTRIA. NR 28 TC 6 Z9 6 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1997 VL 55 IS 6 BP 4351 EP 4376 DI 10.1103/PhysRevA.55.4351 PG 26 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XE372 UT WOS:A1997XE37200055 ER PT J AU Fioretti, A Muller, JH Verkerk, P Allegrini, M Arimondo, E Julienne, PS AF Fioretti, A Muller, JH Verkerk, P Allegrini, M Arimondo, E Julienne, PS TI Direct measurement of fine-structure collisional losses from a Cs magneto-optical trap SO PHYSICAL REVIEW A LA English DT Article ID HYPERFINE-STRUCTURE; COLD COLLISIONS; LASER FIELD; ATOMS; SPECTRA AB Losses from a cesium magneto-optical trap induced by fine-structure changing collisions have been measured directly by counting of fluorescence photons emitted at the D-1 resonance line, with the trap lasers operating on the D-2 resonance line. The absolute value of the fine-structure loss rate coefficient has been measured and its dependence on the hyperfine state occupation has been explored. These results provide a fundamental test for the theoretical descriptions of excited-state trap losses. C1 NIST,DIV MOL PHYS,GAITHERSBURG,MD 20899. RP Fioretti, A (reprint author), UNIV PISA,DIPARTIMENTO FIS,UNITA INFM,PIAZZA TORRICELLI 2,I-56126 PISA,ITALY. RI Muller, Jorg Helge/M-5187-2014; Julienne, Paul/E-9378-2012 OI Muller, Jorg Helge/0000-0001-6984-0487; Julienne, Paul/0000-0002-5494-1442 NR 21 TC 29 Z9 29 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1997 VL 55 IS 6 BP R3999 EP R4002 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XE372 UT WOS:A1997XE37200006 ER PT J AU Gatzke, M Birkl, G Jessen, PS Kastberg, A Rolston, SL Phillips, WD AF Gatzke, M Birkl, G Jessen, PS Kastberg, A Rolston, SL Phillips, WD TI Temperature and localization of atoms in three-dimensional optical lattices SO PHYSICAL REVIEW A LA English DT Article ID COLD CESIUM ATOMS; QUANTIZED MOTION; MOLASSES; WAVE; CRYSTAL AB We report temperature measurements of atoms trapped in a three-dimensional (3D) optical lattice, a well-defined laser-cooling situation that can be treated with currently available theoretical tools. We also obtain fluorescence spectra from a 3D optical lattice, from which we obtain quantitative information about the trapping atoms, including the oscillation frequencies, spatial localization, and a temperature, which is in good agreement with our direct measurements. For comparison we study a 1D lattice using the same atom (cesium). C1 NIST,GAITHERSBURG,MD 20899. RI Jessen, Poul/A-5433-2009; rolston, steven/L-5175-2013 OI rolston, steven/0000-0003-1671-4190 NR 24 TC 45 Z9 45 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1997 VL 55 IS 6 BP R3987 EP R3990 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA XE372 UT WOS:A1997XE37200003 ER PT J AU Savin, S Harris, AB Yildirim, T AF Savin, S Harris, AB Yildirim, T TI Towards a microscopic approach to the intermolecular interaction in solid C-60 SO PHYSICAL REVIEW B LA English DT Article ID SINGLE-CRYSTAL C-60; ORIENTATIONAL ORDERING TRANSITION; MOLECULAR-DYNAMICS; PHASE-TRANSITION; GROUND-STATE; X-RAY; C60; BUCKMINSTERFULLERENE; DISORDER; COMPRESSIBILITY AB Although the calculation of the ground-state and thermodynamic properties of solid C-60 have been the subject of intense research, our understanding is still based on ad hoc models that treat phenomenologically both the Coulomb and short-range part of the interaction potential between C-60 molecules. These potentials do not predict well those properties not fitted to fix the free parameters of the model, and they also do not properly represent the Coulomb interaction between molecules. To remedy this situation, here we introduce a semiempirical model in which the Coulomb interaction is treated microscopically using the local-density approximation C-60 molecular charge densities, and the short-range part of the potential is modeled phenomenologically via Lennard-Jones (LJ) 12-6 interactions between the centers, delocalized over the surfaces of C-60 molecules. The regular LJ parameters sigma and epsilon as well as multipole moments of the interaction centers distribution were taken to reproduce the details of the observed low-temperature structure. We found that the Coulomb interaction is dominated by the charge overlap between the neighboring C-60 molecules, and is much larger than the interaction calculated using the multipole expansion of the charge densities. Contrary to common belief, this Coulomb interaction by itself does not lead to the observed low-temperature structure. However, combined with the proposed short-range interaction, it stabilizes Pa(3) over bar spatial structure with the correct setting angle. We make a comprehensive comparison between the wide range of experimental results and predictions of our, as well as previously proposed models. Our results show that the proposed model has the best overall agreement with the experimental observations in both the low- and high-temperature phases. C1 UNIV MARYLAND, COLLEGE PK, MD 20742 USA. NATL INST STAND & TECHNOL, GAITHERSBURG, MD 20899 USA. RP Savin, S (reprint author), UNIV PENN, DEPT PHYS, PHILADELPHIA, PA 19104 USA. RI yildirim, taner/A-1290-2009; harris, A Brooks/C-8640-2013 NR 55 TC 37 Z9 37 U1 0 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1997 VL 55 IS 21 BP 14182 EP 14199 DI 10.1103/PhysRevB.55.14182 PG 18 WC Physics, Condensed Matter SC Physics GA XE371 UT WOS:A1997XE37100037 ER PT J AU Huang, Q Santoro, A Lynn, JW Erwin, RW Borchers, JA Peng, JL Greene, RL AF Huang, Q Santoro, A Lynn, JW Erwin, RW Borchers, JA Peng, JL Greene, RL TI Structure and magnetic order in undoped lanthanum manganite SO PHYSICAL REVIEW B LA English DT Article ID DEFECT CHEMISTRY; LAMNO3+/-DELTA; MAGNETORESISTANCE; LAMNO3+DELTA; DENSITY; FILMS AB The undoped lanthanum manganite system of nominal composition LaMnO3 has been analyzed by neutron powder diffraction for different sample heat treatment methods. Four distinct crystallographic phases have been identified: (i) an orthorhombic phase of space group Pnma and lattice parameters (at 300 K) a = 5.7385(3), b = 7.7024(3), c = 5.5378(2) Angstrom, produced by annealing in a reducing atmosphere. The system develops long-range antiferromagnetic order below T-N = 140 K With the Mn3+ spins coupled ferromagnetically in the a-c plane and antiferromagnetically along b, with the spin direction along a. The volume of this phase increases monotonically with increasing temperature, but both the a and c lattice parameters exhibit negative thermal expansion in alternate temperature regimes. (ii) A second (previously unreported) orthorhombic phase that exhibits a smaller splitting, also of space group Pnma and lattice parameters (at 300 K) a = 5.4954(3), b = 7.7854(4), c = 5.5355(3) Angstrom, produced by annealing in an oxygen (or air) atmosphere. This system orders with a simple ferromagnetic structure at T-c = 140 K, with the spin direction along c. Phases (i) and (ii) can be transformed reversibly by suitable heat treatment of the same sample, and exist with a range of lattice parameters and compositions. The unit-cell volume for the antiferromagnetic phase is considerably larger than for the ferromagnetic phase, which agrees with the double-exchange model proposed for this system. (iii) A monoclinic phase of space group P112(1)/a and lattice parameters (at 200 K) a = 5.4660(4), b = 7.7616(7), c = 5.5241(5) Angstrom, gamma = 90.909 degrees(5) that orders ferromagnetically below 140 K. (iv) A rhombohedral phase of space group R(3) over barc$ and hexagonal lattice parameters (at 300 K) a = 5.5259(2), c = 13.3240(4) Angstrom, that is observed only above room temperature. Occupancy refinements show that phase (i) ideally has the stoichiometric composition LaMnO3, while the results for the Mn-O bond distances suggest that phases (ii), (iii), and (iv) are progressively richer in oxygen (and thus Mn4+). The results of our study strongly suggest the progressive development of cation vacancies in equal numbers on the La and Mn sites as the oxygen content is increased by heat treatment. In the monoclinic phase the Mn ions occupy two crystallographically independent sites, but no evidence of ordering of Mn3+ and Mn4+ was observed. The structures of the four phases are closely related to that of perovskite. The MnO6 octahedra are tilted from the undistorted configuration, the tilt system being a(-)a(-)a(-) in the rhombohedral structure and a(+)b(-)b(-) in both orthorhombic modifications. C1 UNIV MARYLAND,MAT RES PROGRAM,COLLEGE PK,MD 20742. UNIV MARYLAND,CTR SUPERCOND RES,COLLEGE PK,MD 20742. RP Huang, Q (reprint author), NIST,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899, USA. NR 22 TC 260 Z9 266 U1 4 U2 58 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1997 VL 55 IS 22 BP 14987 EP 14999 DI 10.1103/PhysRevB.55.14987 PG 13 WC Physics, Condensed Matter SC Physics GA XF602 UT WOS:A1997XF60200045 ER PT J AU Gonzalez, EJ WongNg, W Piermarini, GJ Wolters, C Schwartz, J AF Gonzalez, EJ WongNg, W Piermarini, GJ Wolters, C Schwartz, J TI X-ray diffraction study of HgBa2CuO4+delta at high pressures SO POWDER DIFFRACTION LA English DT Article ID SUPERCONDUCTING TRANSITION-TEMPERATURE; INDUCED STRUCTURAL-CHANGES; HYDROSTATIC-PRESSURE; ANISOTROPIC COMPRESSIBILITY; CHARGE-TRANSFER; BULK MODULUS; DEPENDENCE; HGBA2CAN-1CUNO2N+2+DELTA; T(C) AB An in situ high pressure study using energy dispersive X-ray diffraction has been carried out on the polycrystalline high-T-c superconductor, HgBa2CuO4+delta (Hg-1201), to study its phase stability under pressure and also to measure its compressibility and bulk modulus. No evidence of pressure-induced polymorphism was found in the pressure range investigated, i.e., from 0.1 MPa (1 atm) to 5 GPa. The compound exhibited anisotropic elastic properties. The axial compressibility along the c axis was measured to be (3.96 +/- 0.35) x 10(-3) GPa(-1) and along the a axis (3.42 +/- 0.13) x 10(-3) GPa(-1), corresponding to an anisotropy ratio of 1.16 +/- 0.11. The bulk modulus was determined to be (94.7 +/- 4.2) GPa and, assuming a Poisson's ratio of 0.2, Young's modulus was estimated to be (170 +/- 8) GPa. (C) 1997 International Centre for Diffraction Data. C1 FLORIDA STATE UNIV,NATL HIGH MAGNET FIELD LAB,TALLAHASSEE,FL 32306. RP Gonzalez, EJ (reprint author), NIST,DIV CERAM,GAITHERSBURG,MD 20899, USA. RI Schwartz, Justin/D-4124-2009 OI Schwartz, Justin/0000-0002-7590-240X NR 33 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0885-7156 J9 POWDER DIFFR JI Powder Diffr. PD JUN PY 1997 VL 12 IS 2 BP 106 EP 112 PG 7 WC Materials Science, Characterization & Testing SC Materials Science GA XG690 UT WOS:A1997XG69000010 ER PT J AU Loezos, JM Vanderah, TA Drews, AR Roth, RS AF Loezos, JM Vanderah, TA Drews, AR Roth, RS TI A series of ''chemically twinned rutile'' oxides, SrM2n+1O4n+5 (M=Ti, Nb; n=3->9) SO POWDER DIFFRACTION LA English DT Article DE SrO-TiO2-Nb2O5; strontium titanium niobates; chemical twinning; rutile slabs; x-ray powder diffraction data AB X-ray powder diffraction data and refined unit cell parameters for SrTi3Nb4O17, SrTi5Nb4O21, SrTi7Nb4O25, SrTi9Nb4O29, SrTi11Nb4O33, SrTi13Nb4O37, and SrTi15Nb4O41 are reported here. The powder patterns for these oxides suggest that they form a homologous series SrM2n+1O4n+5 (M = Ti, Nb; n = 3 --> 9), which is isostructural with the orthorhombic ''chemically twinned rutile'' series found previously in the K2O-TiO2-Ta2O5 and BaO-TiO2-Nb2O5 systems. The structures are built of corner-sharing slabs of the rutile structure; successive members are generated by adding 2TiO(2) to the slab thickness of the previous member. The series crystallizes in space group Cmcm (No. 63), with members exhibiting similar a-, b-dimensions (similar to 6.6, similar to 8.9 Angstrom; respectively), and c-dimensions that linearly increase (by similar to 4.4 Angstrom per member) from 20.8 Angstrom for n = 3 to 47.1 Angstrom for n = 9. (C) 1997 International Centre for Diffraction Data. RP Loezos, JM (reprint author), NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899, USA. NR 8 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0885-7156 J9 POWDER DIFFR JI Powder Diffr. PD JUN PY 1997 VL 12 IS 2 BP 117 EP 125 PG 9 WC Materials Science, Characterization & Testing SC Materials Science GA XG690 UT WOS:A1997XG69000012 ER PT J AU Abdulaev, NG Popp, MP Smith, WC Ridge, KD AF Abdulaev, NG Popp, MP Smith, WC Ridge, KD TI Functional expression of bovine opsin in the methylotrophic yeast Pichia pastoris SO PROTEIN EXPRESSION AND PURIFICATION LA English DT Article ID DOMINANT RETINITIS-PIGMENTOSA; HIGH-LEVEL EXPRESSION; SACCHAROMYCES-CEREVISIAE; SCHIZOSACCHAROMYCES-POMBE; MONOCLONAL-ANTIBODIES; VISUAL RHODOPSIN; COMPETITIVE PCR; RECEPTOR; GENE; SEQUENCE AB The methylotrophic yeast Pichia pastoris was examined for functional expression of bovine opsin. An expression plasmid was constructed where the bovine opsin gene was placed downstream from the P. pastoris alcohol oxidase 1 gene promoter and fused at its amino-terminus to the acid phosphatase secretion signal, Quantitative-competitive PCR analysis of a stable yeast transformant showed that one copy of the opsin gene was integrated into the yeast genome. The expression level in this transformant corresponded to similar to 0.3 mg of opsin per liter of cell culture (A(600) = 1.0). Sucrose density sedimentation analysis indicated that the opsin was associated exclusively with the membrane fraction. Similar to retinal opsin, P. pastoris-expressed opsin migrated as a single band of similar to 37 kDa on SDS-PAGE and showed high mannose N-glycosylation. A portion of the expressed opsin (similar to 4-15%) reacted with 11-cis-retinal to form the rhodopsin chromophore (lambda(max) 500 nm), and after purification showed ground and excited state spectral characteristics indistinguishable from those of the native pigment. Further, the metarhodopsin-II-mediated G-protein-activating potential of yeast expressed rhodopsin was similar to that of native rhodopsin. These results show that P. pastoris cells have the capacity to functionally express bovine opsin. (C) 1997 Academic Press. C1 NATL INST STAND & TECHNOL,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. UNIV MARYLAND,MARYLAND BIOTECHNOL INST,ROCKVILLE,MD 20850. SHEMYAKIN & OVCHINNIKOV INST BIOORGAN CHEM,MOSCOW,RUSSIA. UNIV FLORIDA,DEPT OPHTHALMOL,GAINESVILLE,FL 32610. FU NEI NIH HHS [EY06641, EY11112] NR 46 TC 32 Z9 32 U1 2 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 1046-5928 J9 PROTEIN EXPRES PURIF JI Protein Expr. Purif. PD JUN PY 1997 VL 10 IS 1 BP 61 EP 69 DI 10.1006/prep.1996.0704 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA XB791 UT WOS:A1997XB79100009 PM 9179292 ER PT J AU Britz, G Emerling, D Hare, L Hoerl, R Shade, J AF Britz, G Emerling, D Hare, L Hoerl, R Shade, J TI How to teach others to apply statistical thinking SO QUALITY PROGRESS LA English DT Article C1 IMAT CO,OAKDALE,MN. NATL INST STAND & TECHNOL,STAT ENGN DIV,GAITHERSBURG,MD 20899. GE CO,SCHENECTADY,NY. NABISCO,CONTINUOUS IMPROVEMENT,PARSIPPANY,NJ. RP Britz, G (reprint author), 3M CTR,ST PAUL,MN 55144, USA. NR 6 TC 0 Z9 0 U1 1 U2 3 PU AMER SOC QUALITY CONTROL-ASQC PI MILWAUKEE PA ASQC MEMBERSHIP MANAGER 611 E. WISCONSIN AVENUE, MILWAUKEE, WI 53202 SN 0033-524X J9 QUAL PROG JI Qual. Prog. PD JUN PY 1997 VL 30 IS 6 BP 67 EP 79 PG 13 WC Engineering, Multidisciplinary; Engineering, Industrial; Management; Operations Research & Management Science SC Engineering; Business & Economics; Operations Research & Management Science GA XD660 UT WOS:A1997XD66000032 ER PT J AU Postek, MT Vladar, AE AF Postek, MT Vladar, AE TI Inexpensive digital imaging? SO SCANNING LA English DT Article DE scanning electron microscopy; frame grabber; TV-rate imaging AB The capture of digital images through the use of a frame grabber provides tremendous advantages to scanning electron microscopy. Accessory frame gabbers can range in price from very inexpensive to several thousand dollars. This work investigates the application of one inexpensive ''consumer product'' frame grabber which has recently been introduced to scanning electron microscope (SEM) imaging. The application of this frame grabber to the SEM as a low-cost, entry-level digital imaging tool is explored, and its performance is compared with a more expensive system. C1 HEWLETT PACKARD LABS,USLI RES LAB,PALO ALTO,CA. RP Postek, MT (reprint author), NIST,NANOMETER SCALE METROL GRP,TECHNOL A-347,GAITHERSBURG,MD 20899, USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430 SN 0161-0457 J9 SCANNING JI Scanning PD JUN PY 1997 VL 19 IS 4 BP 297 EP 299 PG 3 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA XF007 UT WOS:A1997XF00700010 ER PT J AU Hwang, JH Kirkpatrick, KS Mason, TO Garboczi, EJ AF Hwang, JH Kirkpatrick, KS Mason, TO Garboczi, EJ TI Experimental limitations in impedance spectroscopy .4. Electrode contact effects SO SOLID STATE IONICS LA English DT Article DE impedance spectroscopy; point contact; contact impedance ID CEMENT PASTE AB A 'spreading resistance' contact between electrode and specimen can increase or even dominate the apparent bulk resistance of an electroceramic specimen. For true point contacts, a single are will appear in impedance spectra, whose diameter is essentially the spreading resistance due to the contact and whose time constant is identical to that of the bulk, but with a correspondingly smaller capacitance. When a planar electrode with multiple point contacts is involved, a separate electrode are occurs whose diameter is due to spreading resistance, but whose capacitance tends to be dominated by the 'air gap' capacitance between the electrode and the rough surface of the ceramic. In this study impedance spectroscopy was employed to study the effects of temperature, oxygen partial pressure, and mechanical loading on the contact impedance of gold electrodes on nanophase cerium dioxide. Results were confirmed by pixel-based computer simulations. C1 NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,EVANSTON,IL 60208. NATL INST STAND & TECHNOL,BLDG MAT DIV,GAITHERSBURG,MD 20899. RI Mason, Thomas/B-7528-2009 NR 23 TC 70 Z9 70 U1 0 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD JUN PY 1997 VL 98 IS 1-2 BP 93 EP 104 DI 10.1016/S0167-2738(97)00075-1 PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA XH789 UT WOS:A1997XH78900012 ER PT J AU Schneir, J Jobe, R Tsai, VW AF Schneir, J Jobe, R Tsai, VW TI High-resolution profilometry for CMP process control SO SOLID STATE TECHNOLOGY LA English DT Article AB Chemical-mechanical polishing (CMP) process cells commonly use profilometry to measure the post-CMP planarization of the wafer. However, as the feature size of ultra large-scale integration technology decreases, it has become increasingly difficult to resolve individual surface features using a profiler. Here we present a new instrument, a high-resolution profiler (HRP), which can be used for surface metrology in the spatial wavelength range of 30 mm to 10 nm. HRP can, for the first time, measure the wafer surface on the macroscopic and microscopic scale with the same instrument. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. UNIV MARYLAND,COLLEGE PK,MD 20742. RP Schneir, J (reprint author), TENCOR INSTRUMENTS,METROL DIV,1 TECHNOL DR,MILPITAS,CA 95035, USA. NR 3 TC 2 Z9 2 U1 0 U2 1 PU PENNWELL PUBL CO SOLID STATE TECHNOLOGY OFFICE PI NASHUA PA TEN TARA BLVD 5TH FLOOR, NASHUA, NH 03062-2801 SN 0038-111X J9 SOLID STATE TECHNOL JI Solid State Technol. PD JUN PY 1997 VL 40 IS 6 BP 203 EP & PG 5 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA XD016 UT WOS:A1997XD01600032 ER PT J AU Galt, JA AF Galt, JA TI The integration of trajectory models and analysis into spill response information systems SO SPILL SCIENCE & TECHNOLOGY BULLETIN LA English DT Article DE oil spill; trajectory model; spill response; response information systems; trajectory analysis AB The spill response community is engaged in a technological rush towards computer-based, information-synthesis systems. Typically, they are modeled after many successful 'incident command' or 'command and control' systems that rely on micro- or mini-computer technology that is friendly and graphically oriented. Virtually all of these systems offer spill trajectory modeling components. What is typically lacking in this modeling output is any reliable way to estimate the uncertainty. This means that advice derived from the models is of questionable value, and when integrated into a complex response plan, the propagation of errors could seriously compromise the usefulness of results. It is shown that no single trajectory model run can provide the necessary information to respond in an optimal,'minimum regret' strategy. However, a well-defined series of model runs used as the basis for trajectory analysis can provide the required information. A discussion of options suggests that the adoption of a minimum standard analysis procedure would significantly improve the ability of integrated response systems to use the predictions of oil distributions. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NOAA, Hazardous Mat Assessment & Response Div, Seattle, WA 98115 USA. RP Galt, JA (reprint author), NOAA, Hazardous Mat Assessment & Response Div, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 11 TC 5 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1353-2561 J9 SPILL SCI TECHNOL B JI Spill Sci. Technol. Bull. PD JUN PY 1997 VL 4 IS 2 BP 123 EP 129 DI 10.1016/S1353-2561(98)00008-5 PG 7 WC Engineering, Environmental; Engineering, Petroleum SC Engineering GA 108EE UT WOS:000075252400007 ER PT J AU Roper, CFE Vecchione, M AF Roper, C. F. E. Vecchione, M. TI IN SITU OBSERVATIONS TEST HYPOTHESES OF FUNCTIONAL MORPHOLOGY IN MASTIGOTEUTHIS (CEPHALOPODA, OEGOPSIDA) SO VIE ET MILIEU-LIFE AND ENVIRONMENT LA English DT Article DE CEPHALOPODS; SQUID; SUBMERSIBLE; DEEP SEA; BEHAVIOR; FUNCTIONAL MORPHOLOGY AB Mastigoteuthis magna observed in situ has a characteristic "tuning fork" posture that can be used as an aid for identification, even for very small squids. Observations of living Mastigoteuthis from submersibles in the western Atlantic Ocean enabled us to test formerly proposed hypotheses concerning functional morphology of these deep sea squids. Hypotheses supported by observations on live animals include : 1) The large fins provide propulsion; simple and double sinusoidal waves move anteriorly or posteriorly, fins flap powerfully, fins roll together ventrally to squeeze water out anteriorly or posteriorly. 2) Tentacular suckers have weak release mechanism; tentacular clubs on live animals feel very sticky, like fly paper, and must be firmly pulled off observer's skin and aquarium wall. 3) Tentacular suckers have sensory function; tentacular tips skim along bottom to allow animal to maintain position in food-rich benthic boundary layer. Observations do not support these hypotheses : 1) Vacuolated arms and head induce head-upwards posture; observations confirm a head-downwards posture maintained by constantly maneuvering fins. 2) Ventral arms lock together to form "gutter" for feeding; live animals hold long ventral arms far apart with proximal part of tentacles enveloped in tentacular sheaths, allowing them to serve as non-tangling trolling lines fishing for minute prey. 3) Well developed eyes and ink sac indicate photic zone habitat; all observations of Mastigoteuthis from submersibles are close to the bottom below 500 m, never in photic zone. We suggest Mastigoteuthis evolved from a Chiroteuthis-like ancestor; its adaptive characters enable it to inhabit the unique trophic zone immediately above the deep sea bottom, feeding on small zooplankters with trolled, non-tangling tentacles. C1 [Roper, C. F. E.] Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. [Vecchione, M.] Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. RP Roper, CFE (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. NR 17 TC 20 Z9 20 U1 0 U2 0 PU OBSERVATOIRE OCEANOLOGIQUE BANYULS PI BANYULS-SUR-MER CEDEX PA LABORATOIRE ARAGO, BP 44, 66651 BANYULS-SUR-MER CEDEX, FRANCE SN 0240-8759 J9 VIE MILIEU JI Vie Milieu PD JUN PY 1997 VL 47 IS 2 BP 87 EP 93 PG 7 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA V22EH UT WOS:000208258000002 ER PT J AU Vecchione, M Young, RE AF Vecchione, M. Young, R. E. TI ASPECTS OF THE FUNCTIONAL MORPHOLOGY OF CIRRATE OCTOPODS: LOCOMOTION AND FEEDING SO VIE ET MILIEU-LIFE AND ENVIRONMENT LA English DT Article DE CEPHALOPOD; OCTOPODA; CIRRATA; IN-SITU; BEHAVIOR; SWIMMING; MUCUS-FEEDING; ANATOMY; SUBMERSIBLE; DEEP-SEA; STAUROTEUTHIS; GRIMPOTEUTHIS AB Cirrate octopods swim by a combination of fin action and medusoid propulsion by the arm/web complex. The fins of cirrate octopods are associated with a unique cartilage-like shell in a shell sac. In cross-section, the fins have distinct proximal and distal regions, both of which are covered by a thin surface sheath of muscle. The distal region is characterized by dorsal and ventral layers of muscle somewhat similar to a typical decapod fin. In the proximal region, the fin cartilage forms a flat central core within the fin and provides skeletal support for attachment of densely packed muscle. Whereas Stauroteuthis maneuvers slowly by sculling with the fins, Grimpoteuthis swims primarily using powerful fin strokes. In Stauroteuthis, the mantle is extensively modified. The mantle opening closely surrounds the funnel, and the posterior mantle muscle is thickened and probably controls water flow for respiration. The "secondary web" in some cirrate species results from a modification of the way the web muscles attach to the arms. The more benthic opisthoteuthids lack this modification. The secondary web enables larger volumes of water to be trapped in the web in some postures. The entrapment of water resulting in a bell-shaped posture in Stauroteuthis could be related to predator defense or to feeding. Buccal secretory glands found in Stauroteuthis and the presence of small copepods in the digestive tract, suggest that this benthopelagic species feeds by entrapping planktonic prey in mucus. C1 [Vecchione, M.] Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. [Young, R. E.] Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. RP Vecchione, M (reprint author), Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. NR 29 TC 25 Z9 25 U1 2 U2 12 PU OBSERVATOIRE OCEANOLOGIQUE BANYULS PI BANYULS-SUR-MER CEDEX PA LABORATOIRE ARAGO, BP 44, 66651 BANYULS-SUR-MER CEDEX, FRANCE SN 0240-8759 J9 VIE MILIEU JI Vie Milieu PD JUN PY 1997 VL 47 IS 2 BP 101 EP 110 PG 10 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA V22EH UT WOS:000208258000004 ER PT J AU Vecchione, M AF Vecchione, M. TI COMMENTARY ON THE INTERNATIONAL SYMPOSIUM ON FUNCTIONAL MORPHOLOGY OF CEPHALOPODS SO VIE ET MILIEU-LIFE AND ENVIRONMENT LA English DT Editorial Material C1 Natl Museum Nat Hist, NMFS Systemat Lab, Washington, DC 20560 USA. RP Vecchione, M (reprint author), Natl Museum Nat Hist, NMFS Systemat Lab, Washington, DC 20560 USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU OBSERVATOIRE OCEANOLOGIQUE BANYULS PI BANYULS-SUR-MER CEDEX PA LABORATOIRE ARAGO, BP 44, 66651 BANYULS-SUR-MER CEDEX, FRANCE SN 0240-8759 J9 VIE MILIEU JI Vie Milieu PD JUN PY 1997 VL 47 IS 2 BP 183 EP 184 PG 2 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA V22EH UT WOS:000208258000016 ER PT J AU Reish, DJ Oshida, PS Mearns, AJ Ginn, TC GodwinSaad, EM Buchman, M AF Reish, DJ Oshida, PS Mearns, AJ Ginn, TC GodwinSaad, EM Buchman, M TI Effects of pollution on saltwater organisms SO WATER ENVIRONMENT RESEARCH LA English DT Review ID METAL C1 US EPA,WASHINGTON,DC 20460. ADVENT GRP,BRENTWOOD,TN. NOAA,SEATTLE,WA. PTI ENVIRONM SERV,BELLEVUE,WA. RP Reish, DJ (reprint author), CALIF STATE UNIV LONG BEACH,DEPT BIOL SCI,LONG BEACH,CA 90840, USA. NR 170 TC 4 Z9 4 U1 0 U2 2 PU WATER ENVIRONMENT FEDERATION PI ALEXANDRIA PA 601 WYTHE ST, ALEXANDRIA, VA 22314-1994 SN 1061-4303 J9 WATER ENVIRON RES JI Water Environ. Res. PD JUN PY 1997 VL 69 IS 4 BP 877 EP 892 DI 10.2175/106143097X135091 PG 16 WC Engineering, Environmental; Environmental Sciences; Limnology; Water Resources SC Engineering; Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA XH757 UT WOS:A1997XH75700041 ER PT J AU Branick, ML AF Branick, ML TI A climatology of significant winter-type weather events in the contiguous United States, 1982-94 SO WEATHER AND FORECASTING LA English DT Article AB A dataset of all significant winter-type weather events reported in Storm Data within the contiguous United States from 1982 through 1994 has been compiled. Statistical analysis of this dataset is used to determine climatological frequencies of winter weather, including seasonal fluctuations, relative frequencies of different hazards (e.g., heavy snow vs freezing precipitation), duration variations, and size (areal coverage) distributions. Findings are intended to assist in development of operational forecasting issues such as staffing requirements, forecast formats and lead times, and local and regional winter weather preparedness activities. In particular, the database is intended to assist in these issues as they apply to the Storm Prediction Center (SPC), which will begin operational short-term forecasting of hazardous winter weather in fall 1997. From the 13-yr database of 1663 events and 2075 event days, significant winter weather is shown to occur somewhere within the contiguous United States almost daily from mid-November through March. High frequencies of winter weather persist into the springtime climatological period of high severe convection frequencies, suggesting the potential need for extra manpower at the SPC during periods of concurrent multiple hazards. Size distributions indicate a marked prevalence of small-scale events, suggesting the importance of mesoscale processes and the need to develop further understanding thereof before effective short-term forecasting of winter weather can improve. Heavy snow was reported in more than 80% of all events, while significant freezing precipitation was reported in about one-fourth of all events. A second goal is to determine the reliability of Storm Data as an observational database for winter weather forecast verification. Examination of Storm Data over the 13-yr period reveals several shortcomings, including a lack of consistency in the way winter weather events are reported from state to state. Although it is shown that a useful database can be constructed from Storm Data, it also is shown that improvements are needed before such a database can be used routinely for forecast verification. Suggestions are offered for establishing greater consistency in Storm Data, as well as for improving real-time verification and ground-truth information by expanding the role of real-time local storm reports to include winter weather in addition to severe convective reports. RP Branick, ML (reprint author), NATL WEATHER SERV,FORECAST OFF,1200 WESTHEIMER DR,NORMAN,OK 73069, USA. NR 6 TC 31 Z9 33 U1 2 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1997 VL 12 IS 2 BP 193 EP 207 DI 10.1175/1520-0434(1997)012<0193:ACOSWT>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XF203 UT WOS:A1997XF20300001 ER PT J AU Tuleya, RE Lord, SJ AF Tuleya, RE Lord, SJ TI The impact of dropwindsonde data on GFDL hurricane model forecasts using global analyses SO WEATHER AND FORECASTING LA English DT Article ID TRACK FORECASTS; SYSTEM; IMPROVEMENTS AB The National Centers for Environmental Prediction (NCEP) and the Hurricane Research Division (HRD) of NOAA have collaborated to postprocess Omega dropwindsonde (ODW) data into the NCEP operational global analysis system for a series of 14 cases of Atlantic hurricanes (or tropical storms) from 1982 to 1989. Objective analyses were constructed with and without ingested ODW data by the NCEP operational global system. These analyses were then used as initial conditions by the Geophysical Fluid Dynamics Laboratory (GFDL) high-resolution regional forecast model. This series of 14 experiments with and without ODWs indicated the positive impacts of ODWs on track forecasts using the GFDL model. The mean forecast track improvement at various forecast periods ranged from 12% to 30% relative to control eases without ODWs: approximately the same magnitude as those of the NCEP global model and higher than those of the VICBAR barotropic model for the same 14 cases. Mean track errors were reduced by 12 km at 12 h, by similar to 50 km for 24-60 h, and by 127 km at 72 h (nine cases). Track improvements were realized with ODWs at similar to 75% of the verifying times for the entire 14-case ensemble. With the improved analysis using ODWs, the GFDL model was able to forecast the interaction of Hurricane Floyd (1987) with an approaching midlatitude trough and the storm's associated movement from the western Caribbean north, then northeastward from the Gulf of Mexico into the Atlantic east of Florida. In addition, the GFDL model with ODWs accurately forecasted the rapid approach and landfall of Hurricane Hugo (1989) onto the U.S. mainland. An assessment of the differences between analyses indicates that the impact of ODWs can be attributable in part to differences of similar to 1 m s(-1) in steering flow of the initial state. In addition to track error, the skill of intensity prediction using the ODW dataset was also investigated. Results indicate a positive impact on intensity forecasts with ODW analyses. However, the overall skill relative to the National Hurricane Center statistical model SHIFOR is shown only after 2 or 3 days. It is speculated that with increased data coverage such as ODWs bath track and intensity error can be further reduced provided that data sampling can be optimized and objective analysis techniques utilizing asynoptic data can be developed and improved. C1 NOAA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ USA. NOAA, NATL CTR ENVIRONM PREDICT, WASHINGTON, DC USA. NR 22 TC 21 Z9 22 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 EI 1520-0434 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1997 VL 12 IS 2 BP 307 EP 323 DI 10.1175/1520-0434(1997)012<0307:TIODDO>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XF203 UT WOS:A1997XF20300007 ER PT J AU Hirschberg, PA Parke, MC Wash, CH Mickelinc, M Spencer, RW Thaler, E AF Hirschberg, PA Parke, MC Wash, CH Mickelinc, M Spencer, RW Thaler, E TI The usefulness of MSU3 analyses as a forecasting aid: A statistical study SO WEATHER AND FORECASTING LA English DT Article ID EXTRATROPICAL CYCLONES; TROPOPAUSE UNDULATIONS; HEIGHT TENDENCY; ANALYTIC MODEL; UNITED-STATES; CYCLOGENESIS; CIRCULATION; DIAGNOSIS; VORTICITY; ANOMALIES AB A statistical analysis is performed on a 6-month global dataset consisting of satellite-derived channel 3 Microwave Sounding Unit (MSU3) brightness temperature and various conventionally derived fields to quantify the potential usefulness of MSU3 analyses in the nowcasting and forecasting of baroclinic waves. High positive spatial and temporal correlations are obtained between the MSU3 brightness temperature and 400-100-mb thickness fields over all wavelengths in the data. Slightly lesser positive correlations are found between the MSU3 and the 200-mb temperature. The MSU3-500-mb and MSU3-50-mb height correlation results indicate a scale dependence in the hydrostatic spreading of thickness anomalies in the vertical, Most significantly, relatively high negative MSU3-500-mb height correlations for the short (less than or equal to synoptic scale) wavelength portion of the data suggest that upper-level thermal anomalies are reflected downward and that MSU3 analyses can be used to track midlevel synoptic-scale baroclinic waves. This conclusion is also supported by relatively high negative MSU3-500-mb vorticity and MSU3-dynamic tropopause correlations along the climatological storm tracks. C1 USN,POSTGRAD SCH,DEPT METEOROL,MONTEREY,CA 93943. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,EARTH SYST SCI DIV,HUNTSVILLE,AL 35812. NATL WEATHER SERV,DENVER,CO. NR 34 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1997 VL 12 IS 2 BP 324 EP 346 DI 10.1175/1520-0434(1997)012<0324:TUOMAA>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XF203 UT WOS:A1997XF20300008 ER PT J AU Smith, SB AF Smith, SB TI An interesting mesoscale storm-environment interaction observed just prior to changes in severe storm behavior - Comments SO WEATHER AND FORECASTING LA English DT Editorial Material ID SUPERCELL THUNDERSTORM RP Smith, SB (reprint author), NOAA,NATL WEATHER SERV,OFF SYST DEV,TECH DEV LAB,W-OSD24,1325 E W HIGHWAY,SSMC2,SILVER SPRING,MD 20910, USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1997 VL 12 IS 2 BP 368 EP 372 DI 10.1175/1520-0434(1997)012<0368:COAIMS>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XF203 UT WOS:A1997XF20300010 ER PT J AU Weaver, J Purdom, J AF Weaver, J Purdom, J TI An interesting mesoscale storm-environment interaction observed just prior to changes in severe storm behavior - Reply SO WEATHER AND FORECASTING LA English DT Editorial Material RP Weaver, J (reprint author), COLORADO STATE UNIV,NOAA,NESDID,RAMM BRANCH,CIRA,W LAPORTE AVE,FT COLLINS,CO 80523, USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1997 VL 12 IS 2 BP 373 EP 374 DI 10.1175/1520-0434(1997)012<0373:R>2.0.CO;2 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XF203 UT WOS:A1997XF20300011 ER PT J AU Siles, BA Nackerdien, ZE Collier, GB AF Siles, BA Nackerdien, ZE Collier, GB TI Analysis of DNA fragmentation using a dynamic size-sieving polymer solution in capillary electrophoresis SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE DNA fragmentation; buffer composition; DNA ID APOPTOSIS; DEATH AB Various natural and induced processes cause DNA fragmentation. Examples of these processes include apoptosis, enzymatic digestion, free radical production from ionizing radiation, photoscission by laser radiation and thermal degradation. Slab gel electrophoresis has been used most often to monitor such DNA damage. We have investigated with capillary electrophoresis the use of a new size-sieving polymer solution, TreviSol-CE (TS-CE), to monitor the DNA fragments produced from a variety of degradation processes. This polymer solution provides high run-to-run migration time and peak width reproducibilities and high separation efficiency of double-stranded DNA fragments in the 500 to 7000 base pair size range. Analysis of apoptotic DNA fragments suggested the presence of multiple nucleosomes within each cell type investigated. For irradiated DNA standards, peak width-at-half-height and peak area were used to monitor the progress of DNA fragmentation. For both apoptotic DNA and irradiated DNA standards, fine structural features of fragmentation were revealed. C1 NIST,DIV ANALYT CHEM,GAITHERSBURG,MD 20899. NIST,DIV BIOTECHNOL,GAITHERSBURG,MD 20899. TREVIGEN INC,GAITHERSBURG,MD 20877. NR 13 TC 9 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD MAY 30 PY 1997 VL 771 IS 1-2 BP 319 EP 329 DI 10.1016/S0021-9673(97)00050-2 PG 11 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA XF413 UT WOS:A1997XF41300035 PM 9210317 ER PT J AU Kuo, SC Zhang, ZY Ross, SK Klemm, RB Johnson, RD Monks, PS Thorn, RP Stief, LJ AF Kuo, SC Zhang, ZY Ross, SK Klemm, RB Johnson, RD Monks, PS Thorn, RP Stief, LJ TI Discharge flow-photoionization mass spectrometric study of HNO: Photoionization efficiency spectrum and ionization energy and proton affinity of NO SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID KINETIC DATA-BASE; AB-INITIO; HIGH-RESOLUTION; PHOTOELECTRON-SPECTROSCOPY; ELECTRONIC STATES; COUPLED-CLUSTER; SURFACES; RADICALS; THERMOCHEMISTRY; ISOMERIZATION AB Photoionization efficiency (PIE) spectra of HNO were measured over the wavelength range lambda = 110-125 nm and in the ionization threshold region, lambda = 118-124 nm, using a discharge flow-photoionization mass spectometer (DF-PIMS) apparatus coupled to a synchrotron radiation source. HNO was generated in situ by the following reaction sequence: N + NO --> N-2 + O; O + C2H4 --> CH3 + HCO; HCO + NO --> HNO + CO. The PIE spectrum displays steplike behavior near threshold and an HN-O stretching frequency in the cation of 1972 +/- 67 cm(-1). A value of 10.18(4) +/- 0.01(2) eV for the adiabatic ionization energy (IE) of HNO was obtained from photoionization thresholds, which correspond to the HNO+(X(2)A') <-- HNO(X(1)A') transition. This result is the first PIMS determination of IE(HNO). Also, an ab initio molecular orbital calculation (QCISD(T)/aug-cc-pVQZ) was performed that yields a value for IE(HNO) of 10.186 +/- 0.050 eV, There is good agreement between the experimental and the theoretical values for IE(HNO) reported here and that from a recent photoelectron spectroscopy study. The present experimental value for IE(HNO) was employed along with other, known thermodynamic quantities to obtain values for the heat of formation of the HNO cation and the absolute proton affinity of NO: Delta(f)H degrees(298)(HNO+) = 1089.73 +/- 1.18 kJ mol(-1) (Delta(f)H degrees(0)(HNO+) = 1092.65 +/- 1.18 kJ mol(-1)); PA(298)(NO) = 531.55 +/- 1.26 kJ mol(-1) (PA(0)(NO) = 526.12 +/- 1.26 kJ mol(-1)). C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. NATL INST STAND & TECHNOL,DIV PHYS & CHEM PROPERTIES,GAITHERSBURG,MD 20899. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RI Monks, Paul/H-6468-2016 OI Monks, Paul/0000-0001-9984-4390 NR 77 TC 16 Z9 16 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 29 PY 1997 VL 101 IS 22 BP 4035 EP 4041 DI 10.1021/jp9705941 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XB799 UT WOS:A1997XB79900007 ER PT J AU Krauss, M Osman, R AF Krauss, M Osman, R TI Electronic spectra of the H and OH adducts of cytosine SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID RADICAL-ADDITION; URACIL; DERIVATIVES; PROTONATION; PATTERN; ANIONS; ESR AB Theoretical assignments of the spectra of the H and OH adduct radicals of cytosine are obtained with ab initio multiconfiguration self-consistent-field calculations. The C6OH isomer is substantially more stable than the C5OH, The C6H isomer is slightly more stable than C5H, but both are much less stable than the N3H isomer. The C5 and C6 adducts for both H and OH are found to support transitions in entirely different spectral regions. Visible absorption transitions are found for the C6 adducts in which the open shell orbital is delocalized by conjugating to a neighboring double bond or system of bonds. In C5 adducts, the open-shell orbital remains localized giving rise to absorption transitions in the UV. The calculations show that the very broad absorption observed at 440 nm is the convolution of two transitions for the C6OH isomer and that the observed peak at 340 nm has contributions from both the C5OH and C6OH isomers but is dominated by the absorption of C5OH. The similarity of the absorption pattern of the cytosine and uracil adducts suggest a general behavior in the spectroscopy of pyrimidine adducts. Base radical calculations were reported at the 8th International Congress of Quantum Chemistry, Prague, June 20, 1994. C1 CUNY MT SINAI SCH MED, DEPT PHYSIOL & BIOPHYS, NEW YORK, NY 10029 USA. RP Krauss, M (reprint author), NIST, CTR ADV RES BIOTECHNOL, 9600 GUDELSKY DR, ROCKVILLE, MD 20850 USA. NR 22 TC 13 Z9 13 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 29 PY 1997 VL 101 IS 22 BP 4117 EP 4120 DI 10.1021/jp962862l PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XB799 UT WOS:A1997XB79900017 ER PT J AU Mazur, V Williams, E Boldi, R Maier, L Proctor, DE AF Mazur, V Williams, E Boldi, R Maier, L Proctor, DE TI Initial comparison of lightning mapping with operational time-of-arrival and interferometric systems SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID VHF RADIO PICTURES; FLASHES; THUNDERSTORMS AB The mapping of lightning radiation sources produced by the operational Time-of-Arrival National Aeronautics and Space Administration/Lightning Detection and Ranging (NASA/LDAR) system is compared with that of the Interferometric French Office National D'Etudes et de Recherches Aerospatiales (ONERA-3D) system. The comparison comprises lightning activity in three Florida storms and also individual flashes in one of these storms. Although limited in scope, the comparison and analysis show a significant difference in the representation of lighting radiation by each mapping system. During the duration of a flash, the LDAR data show a continuity in time and a three-dimensional structure of radiation sources. The ONERA-3D radiation source data are more intermittent in time and have a more two-dimensional structure. The distinction between the radiation sources mapped by the two systems is also reflected in the difference between their propagation speeds, 10(4)-10(5) m s(-1), estimated by the LDAR system, and 10(7)-10(8) m s(-1), estimated by the ONERA-3D system. We infer that this difference occurs because most of the radiation sources mapped with LDAR are associated with virgin breakdown processes typical of slowly propagating negative leaders. On the other hand, most of the radiation sources mapped with ONERA-3D are produced by fast intermittent negative breakdown processes typical of dart leaders and K changes as they traverse the previously ionized channels. Thus each operational system may emphasize different stages of the lightning flash, but neither appears to map the entire flash. C1 MIT, LINCOLN LAB, LEXINGTON, MA 02173 USA. NASA, KENNEDY SPACE CTR, KENNEDY SPACE CTR, FL 32899 USA. MIT, RALPH M PARSONS LAB, CAMBRIDGE, MA 02139 USA. RP Mazur, V (reprint author), NOAA, NATL SEVERE STORMS LAB, NORMAN, OK 73069 USA. NR 20 TC 41 Z9 46 U1 3 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 27 PY 1997 VL 102 IS D10 BP 11071 EP 11085 DI 10.1029/97JD00174 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XB488 UT WOS:A1997XB48800005 ER PT J AU Li, J Freidenreich, SM Ramaswamy, V AF Li, J Freidenreich, SM Ramaswamy, V TI Solar spectral weight at low cloud tops SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WATER-VAPOR; RADIATION; ABSORPTION; ATMOSPHERES AB The spectral distribution of the incoming solar irradiance varies substantially from the top of the atmosphere to the surface. This occurs because of the selective spectral attenuation by the various atmospheric constituents. Using a line-by-line and doubling-adding solar radiative transfer model we formulate a prescription that accounts for this variation in the spectral solar irradiance and thereby determine the appropriate spectral weights for low clouds. The results are sufficiently general with respect to cloud top heights ranging from 680 to 860 mbar, while the range of applicability in terms of the solar zenith position extends to sun angles less than 75 degrees. On the basis of the results here we suggest a reference cloud top height of 760 mbar and a reference zenith angle bf 53 degrees. The error in the radiative quantities relative to the ''benchmark'' calculations is generally less than 5% in most of the spectral bands. As a simple application, it is found that the enhancement of cloud absorption in a two band cloud optical properties parameterization can be largely avoided by using this simple modification of the solar spectral irradiance incident at the top of low-lying clouds. C1 PRINCETON UNIV, NOAA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ USA. PRINCETON UNIV, ATMOSPHER & OCEAN SCI PROGRAM, PRINCETON, NJ USA. RI Li, Jiangnan/J-6262-2016 NR 10 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 27 PY 1997 VL 102 IS D10 BP 11139 EP 11143 DI 10.1029/96JD03762 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XB488 UT WOS:A1997XB48800010 ER PT J AU Munroe, TA Marsh, BN AF Munroe, TA Marsh, BN TI Taxonomic status of three nominal species of Indo-Pacific symphurine tonguefishes (Symphurus: Cynoglossidae: Pleuronectiformes) SO ICHTHYOLOGICAL RESEARCH LA English DT Article DE Symphurus trifasciatus; Symphurus microrhynchus; Symphurus holothuriae; taxonomic review AB The taxonomic status of three rarely captured, nominal species of Indo-Pacific symphurine tonguefishes, Symphurus trifasciatus (Alcock, 1894), S. micuorhynchus (Weber, 1913), and S holothuriae Chabanaud, 1948, is resolved. Symphurus microrhynchus, previously known only from three specimens, is redescribed based on 12 specimens. Symphurus holothuriae, previously reported only from the holotype, is a junior subjective synonym of S. microrhynchus. Symphurus trifasciatus is redescribed based on six specimens, including the lectotype designated in this study. Symphurus microrhynchus is distinguished from congeners by a combination of meristic features, head and opercle shape, dorsal-fin position, and features of its pigmentation. The species occurs in relatively shallow tropical waters from Zanzibar through French Polynesia (the only reported occurrence of a shallow-water Symphurus from a locality on the Pacific Plate), including Indonesia, Papua New Guinea, Vietnam, and northwestern Australia. Symphurus trifasciatus, known from deep waters along both coasts of the Indian subcontinent and adjacent waters, has an overall similarity in body shape and meristic features reminiscent of those in S. microrhynchus, but differs notably in having a longer and wider head, a distinctive opercle shape, number of scale rows on the head, and pigmentation pattern. C1 UNIV OXFORD,DEPT ZOOL,OXFORD OX1 3PS,ENGLAND. RP Munroe, TA (reprint author), NATL MUSEUM NAT HIST,NATL SYSTEMAT LAB,NATL MARINE FISHERIES SERV,MRC-153,WASHINGTON,DC 20560, USA. NR 26 TC 13 Z9 14 U1 0 U2 2 PU ICHTHYOLOGICAL SOC JAPAN PI TOKYO PA BUSINESS CENTER ACADEMIC SOC JAPAN, 5-16-9 HONKOMAGOME, BUNKYO-KU, TOKYO 113, JAPAN SN 1341-8998 J9 ICHTHYOL RES JI Ichthyol. Res. PD MAY 26 PY 1997 VL 44 IS 2 BP 189 EP 200 DI 10.1007/BF02678697 PG 12 WC Zoology SC Zoology GA XG985 UT WOS:A1997XG98500010 ER PT J AU Williams, RM Papanikolas, JM Rathje, J Leone, SR AF Williams, RM Papanikolas, JM Rathje, J Leone, SR TI Compositional control of rovibrational wave packets in the E((1)Sigma(+)(g)) ''shelf'' state of Li-2 via quantum-state-resolved intermediate state selection SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID STIMULATED-EMISSION; CHEMICAL-REACTIONS; ULTRASHORT-PULSE; COHERENT CONTROL; PHASE; SPECTROSCOPY; GEOMETRIES; INTENSITY; DYNAMICS; POLAR AB Compositional control in the preparation of rovibrational wave packets is demonstrated in the E((1) Sigma(g)(+)) state of gas-phase Lip molecules using ultrafast pump-probe laser spectroscopy combined with quantum-state-resolved intermediate state selection. The intermediate state, from which subsequent ultrafast excitation occurs, is a stationary rovibrational level in the A((1) Sigma(u)(+)) Li-2, produced by cw laser excitation from the ground X((1) Sigma(g)(+)) state. The effect that the intermediate state has on the final composition of the wave packet is investigated by comparing the transients resulting from ultrafast pump-probe excitation of two different intermediate states (v(A)=14, J(A) = 18 versus v(A) = 13, J(A) = 18). In these experiments the pump wavelength is compensated so that in each case the same E-state eigenstates (v(E) = 13-18, J(E) = J(A)+/-1) make up the wave packet, but with different amplitudes. Theory predicts, and experiments confirm, that the relative amplitudes of the rovibrational eigenstates are strongly dependent upon the intermediate state and determine the spatial and temporal evolution of the wave packet. Evidence for this includes differences in the observed pump-probe transients and dramatically different amplitudes of the beat frequencies in the Fourier analysis of the time-domain transients. Theoretical three-dimensional wave packet simulations highlight how the composition of the wave packet is used to vary its spatial and temporal evolution. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. UNIV COLORADO, DEPT CHEM & BIOCHEM, BOULDER, CO 80309 USA. NR 47 TC 23 Z9 25 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 1997 VL 106 IS 20 BP 8310 EP 8323 DI 10.1063/1.473894 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XA041 UT WOS:A1997XA04100002 ER PT J AU Atkinson, DB Hudgens, JW AF Atkinson, DB Hudgens, JW TI Chemical kinetic studies using ultraviolet cavity ring-down spectroscopic detection: Self-reaction of ethyl and ethylperoxy radicals and the reaction O-2+C2H5->C2H5O2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LASER-ABSORPTION-SPECTROSCOPY; RATE CONSTANTS; GAS-PHASE; MUTUAL INTERACTION; T-C4H9 RADICALS; ALKYL RADICALS; SPECTRUM; TEMPERATURE; C2H5; O-2 AB A laser photolysis reactor that uses cavity ring-down spectroscopic (CRDS) detection was characterized and used to measure the rate coefficients of three benchmark reactions of known importance to ethane oxidation. At 295 K and approximately 700 Pa (5.5 Torr) total pressure, we obtained the self-reaction rate coefficients of k = (1.99 +/- 0.44) x 10(-11) cm(3) molecule(-1) s(-1) for C2H5 + C2H5 and k = (7.26 +/- 2.4) x 10(-14) cm(3) molecule(-1) s(-1) for C2H5O2 + C2H5O2 We obtained k = (2.7 +/- 0.3) x 10(-12) cm(3) molecule(-1) s(-1) for the pseudo-first-order association reaction O-2 + C2H5 + AT We also measured the absorption cross sections of the ethyl radical, sigma(220) = (252 +/- 42) x 10(-20) cm(2) molecule(-1) and sigma(222) 2 (206 +/- 42) x 10(-20) cm(2) molecule(-1) Stated uncertainties are 2 sigma. The new rate coefficients agree with those obtained previously by other methods. The agreement confirms that ultraviolet CRDS detection is a viable tool for experimental determinations of gas-phase radical-radical and radical-molecule reaction late coefficients. C1 NATL INST STAND & TECHNOL,CHEM SCI & TECHNOL LAB,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. NR 56 TC 68 Z9 68 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 22 PY 1997 VL 101 IS 21 BP 3901 EP 3909 DI 10.1021/jp970240+ PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA XB370 UT WOS:A1997XB37000009 ER PT J AU Udovic, TJ Rush, JJ Huang, Q Anderson, IS AF Udovic, TJ Rush, JJ Huang, Q Anderson, IS TI Neutron scattering studies of the structure and dynamics of rare-earth hydrides and deuterides SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT International Symposium on Metal Hydrogen Systems: Fundamentals and Applications CY AUG 25-30, 1996 CL LES DIABLERETS, SWITZERLAND DE hydrogen; deuterium; yttrium; lanthanum; neutron scattering ID TEMPERATURE-DEPENDENCE; OCTAHEDRAL SUBLATTICE; SOLID-SOLUTIONS; HYDROGEN; YTTRIUM; TRANSITIONS; SYSTEMS; LAD2.25 AB The optic-vibrational density of states and the structural arrangement of hydrogen and/or deuterium dissolved in or compounded with the rare-earth metals (RH(D)(x) where 0 2OH. C1 CNRS, CTR FAIBLES RADIOACTIV, F-91198 GIF SUR YVETTE, FRANCE. UNIV MIAMI, ROSENSTIEL SCH MARINE & ATMOSPHER SCI, MIAMI, FL 33149 USA. MIT, DEPT CHEM, INT GLOBAL ATMOSPHER CHEM PROGRAM OFF, CAMBRIDGE, MA 02139 USA. USN, OCEANOG OFF, BAY ST LOUIS, MS 39529 USA. RP Carsey, TP (reprint author), NOAA, ATLANTIC OCEANOG & METEOROL LAB, 4301 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA. RI Carsey, Thomas/B-7939-2014; Fischer, Charles/A-3843-2017 OI Carsey, Thomas/0000-0001-9964-5092; NR 46 TC 17 Z9 17 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1997 VL 102 IS D9 BP 10653 EP 10665 DI 10.1029/96JD03511 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XA717 UT WOS:A1997XA71700005 ER PT J AU Conny, JM Verkouteren, RM Currie, LA AF Conny, JM Verkouteren, RM Currie, LA TI Carbon 13 composition of tropospheric CO in Brazil: A model scenario during the biomass burn season SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MONOXIDE; AMAZONIA; CERRADO; FRACTIONATION; VEGETATION; EMISSIONS; ISOPRENE; RATIOS; FIRE; NOX AB The stable isotopes of carbon and oxygen are potentially powerful tools for distinguishing sources of CO in the troposphere due to isotopic differences among source emissions that are caused by isotope fractionation in formation or reaction. It is incorrect, however, to assume that the CO source strengths estimated using isotopic measurements on single-day air samples truly represent a season and region. Atmospheric transport and dispersion models are useful for selecting representative sampling locations; dates, and duration to adequately reflect isotopic variation. Here a three-dimensional transport and dispersion model was used to predict surface-level (CO)-C-13/(CO)-C-12 ratios at four remote sites in the rain forest and savanna of Brazil during the 1992 burn season. The purpose was to demonstrate the scope of surface-level CO isotopic variation due to isotopically distinct source emissions and changing meteorology. The model included C-13 signatures of four classes of CO sources: biomass burning, oxidized vegetative nonmethane hydrocarbon (NMHC) emissions, atmospheric methane oxidation, and fossil fuel combustion. Among the four model locations, sites 1 and 2 were well within the burn region, site 3 was at the edge of it, and site 4 was well north of it. The model employed the program HY-SPLIT to track air masses and calculate CO concentrations from emissions at satellite-detected burn sites which were mainly in the Brazilian savanna. An average CO delta(13)C value for burned biomass (-21.3 parts per thousand versus PDB) was determined from our delta(13)C measurements of savanna biomass, reported fuel loadings, and the distribution of savanna plant communities in Brazil. Two model scenarios were created, based mainly on the level of CO from fossil fuel combustion. Scenario A had a low CO contribution from this source (15 ppbv), and scenario B had a higher CO contribution (100.1 ppbv). Both model scenarios used -32.2, -48.3, and -25 parts per thousand for CO delta(13)C values for oxidized vegetative NMHC emissions, CH4 oxidation, and fossil fuel combustion, respectively, based on data reported by others. Sensitivity studies showed that at sites closest to the burn region the model was influenced largely by the C-13 composition of burned biomass for both scenarios. At the site farthest from the burn region the model was influenced moderately by the amount of CO emitted per fire, a greater rate of CH4 oxidation, and a higher (CO)-C-13/(CO)-C-12 ratio for fossil fuel combustion, particularly for scenario B. For the model scenario with minimal CO from fossil fuel combustion (scenario A), results showed surface-level delta(13)C values for August 5, 1992, averaging about -23 parts per thousand, close to the average delta(13)C value for biomass burning CO. Model results for August 11, 1992, showed (CO)-C-13/(CO)-C-12 that ratios at sites 1-3 were, again, close to the ratio for biomass burning CO (delta(13)C = -22.6 parts per thousand to -24.7 parts per thousand). The more C-13-enriched values match closely with the most C-13-enriched measurements that have been reported for July/August in the tropics and southern hemisphere when elevated CO levels are driven by emissions from large-scale biomass burning. At site 4 for August 11, 1992, the calculated surface-level delta(13)C average was -32.6 parts per thousand. Thus results indicate that (CO)-C-13/(CO)-C-12 ratios may be highly variable from week to week in the Amazon region during the biomass burn season. Model results suggest that on August 5, 1992, fossil fuel combustion probably did not alter significantly the (CO)-C-13/(CO)-C-12 ratio in surface-level air at sites 1-4, given the low and high levels of CO from fossil fuel combustion defined in the two model scenarios. In addition, measurements taken at sites 1-3 probably would have been indistinguishable from the C-13 composition of the biomass burning source. At site 4 on August 11, however, other CO sources probably altered significantly the (CO)-C-13/(CO)-C-12 ratio in surface air from that of CO from biomass burning. RP Conny, JM (reprint author), NATL INST STAND & TECHNOL, SURFACE & MICROANAL SCI DIV, GAITHERSBURG, MD 20899 USA. NR 31 TC 12 Z9 12 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1997 VL 102 IS D9 BP 10683 EP 10693 DI 10.1029/97JD00407 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XA717 UT WOS:A1997XA71700008 ER PT J AU Bird, JC Pal, SR Carswell, AI Donovan, DP Manney, GL Harris, JM Uchino, O AF Bird, JC Pal, SR Carswell, AI Donovan, DP Manney, GL Harris, JM Uchino, O TI Observations of ozone structures in the Arctic polar vortex SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID POTENTIAL VORTICITY; LOWER STRATOSPHERE; ANTARCTIC VORTEX; WINTER; EVOLUTION; TRANSPORT; FEBRUARY; LAMINAE; MOTION; TRACER AB Lidar and balloon measurements at the new observatory, AStrO (80.05 degrees N, 86.42 degrees W), near Eureka, in the Canadian Arctic, have revealed laminations inside the ozone layer both inside and outside the polar vortex. These observations have been conducted by the lidar group of the Institute for Space and Terrestrial Science during February-March 1993 and the winters of 1993-1994 and 1994-1995. Observations of the vortex edge region were obtained as it passed over Eureka, revealing ozone profiles rich in structure. This paper discusses the observed ozone structures and their relationship to vortex filaments, the vortex edge structure, low-ozone pockets, motion of the vortex edge region in the ozone profiles, and observed temperatures. Complementing the observations are back trajectories, potential vorticity maps, and Lagrangian domain-filling potential vorticity trajectories. The relations of magnitude and thickness of the laminations to their positions relative to the vortex are revealed by presenting data as a function of potential vorticity. Mechanisms for the formation and transport of the laminae are discussed, as well as their role as a possible exchange mechanism of air masses across the polar vortex boundary. From observations of the laminations and their relation to potential vorticity, it is suggested that motion of the vortex, sometimes associated with warmings, is involved in the formation of laminations, which are subsequently advected as filamentary structures. C1 NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. JET PROP LAB, PASADENA, CA 91109 USA. JAPAN METEOROL AGCY, CHIYODA KU, TOKYO 100, JAPAN. YORK UNIV, DEPT PHYS & ASTRON, N YORK, ON M3J 3K1, CANADA. RP Bird, JC (reprint author), YORK UNIV, INST SPACE & TERR SCI, 4850 KEELE ST, N YORK, ON M3J 3K1, CANADA. NR 41 TC 22 Z9 22 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1997 VL 102 IS D9 BP 10785 EP 10800 DI 10.1029/96JD03787 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XA717 UT WOS:A1997XA71700016 ER PT J AU Torikai, N Noda, I Karim, A Satija, SK Han, CC Matsushita, Y Kawakatsu, T AF Torikai, N Noda, I Karim, A Satija, SK Han, CC Matsushita, Y Kawakatsu, T TI Neutron reflection studies on segment distribution of block chains in lamellar microphase-separated structures SO MACROMOLECULES LA English DT Article ID MOLECULAR-WEIGHT DEPENDENCE; DIBLOCK COPOLYMER FILMS; THIN-FILMS; POLYMER; POLYSTYRENE; MORPHOLOGY; BULK; CONFORMATION; EQUILIBRIUM; MICROSCOPY AB Segment distribution of styrene in an alternating lamellar structure of styrene-2-vinylpyridine diblock copolymer was investigated by neutron reflection. Block copolymers having three types of deuterium-labeled styrene block chains consisting of fully labeled, partially junction-labeled, and partially end-labeled block chains were used in this study. The degree of junction and end labeling was varied to obtain a more complete picture of segment distribution. Spin-coated thin films of these block copolymers on silicon wafers exhibited lamellar structures which were oriented preferentially parallel to the silicon surface. Our results indicate that the poly(2-vinylpyridine) block chain exists at the silicon surface, while polystyrene appears at the air surface in all of the film specimens. The segment distribution at the interface between polystyrene and poly(2-vinylpyridine) lamellae could be well described by an error function. The thickness of the lamellar interface (defined as a full-width half-maximum value of the error function) is evaluated to be about 4.5 nm, suggesting that the blocks are strongly segregated. Accordingly, the segments of a block chain in the vicinity of the chemical junction point between two block chains are determined to be strongly localized near the lamellar interface. However, the free ends are broadly distributed throughout the lamellar microdomain with their net maximum distribution at the center of each microdomain. Such an end-segment distribution of the block chains is shown to be consistent with predictions from a mean field theory. C1 UNIV TOKYO, INST SOLID STATE PHYS, NEUTRON SCATTERING LAB, TOKAI, IBARAKI 31911, JAPAN. NAGOYA UNIV, GRAD SCH ENGN, DEPT APPL CHEM, CHIKUSA KU, NAGOYA, AICHI 46401, JAPAN. NIST, GAITHERSBURG, MD 20899 USA. TOKYO METROPOLITAN UNIV, DEPT PHYS, HACHIOJI, TOKYO 19203, JAPAN. NR 33 TC 51 Z9 51 U1 0 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 EI 1520-5835 J9 MACROMOLECULES JI Macromolecules PD MAY 19 PY 1997 VL 30 IS 10 BP 2907 EP 2914 DI 10.1021/ma961089p PG 8 WC Polymer Science SC Polymer Science GA XA232 UT WOS:A1997XA23200015 ER PT J AU Holland, MJ Jin, DS Chiofalo, ML Cooper, J AF Holland, MJ Jin, DS Chiofalo, ML Cooper, J TI Emergence of interaction effects in Bose-Einstein condensation SO PHYSICAL REVIEW LETTERS LA English DT Article ID GAS; ATOMS AB We present a quantitative evaluation of the predictions of mean-field theory for describing a Bose-Einstein condensate in a magnetic trap by comparing directly with experimental observations. We study the release energy from ballistic expansion and the cloud density profile as a function of mean-field effects. Significant departure of the cloud shape from both the noninteracting limit and the strongly repulsive limit is observed for our parameters, consistent with theoretical prediction. C1 UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. SCUOLA NORMALE SUPER PISA,PISA,ITALY. INFM,PISA,ITALY. RP Holland, MJ (reprint author), NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. NR 20 TC 75 Z9 75 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 19 PY 1997 VL 78 IS 20 BP 3801 EP 3805 DI 10.1103/PhysRevLett.78.3801 PG 5 WC Physics, Multidisciplinary SC Physics GA WZ244 UT WOS:A1997WZ24400001 ER PT J AU LeGarrec, JL Lepage, V Rowe, BR Ferguson, EE AF LeGarrec, JL Lepage, V Rowe, BR Ferguson, EE TI The temperature dependence of the rate constant for O++NO->NO++O from 23 to 30000 K SO CHEMICAL PHYSICS LETTERS LA English DT Article ID NEUTRAL REACTIONS; ENERGY; NO+; O+ AB The rate constant, k, for the charge transfer reaction O+ + NO --> NO+ + O, known to be slow at 300 K (8 x 10(-13) cm(3) s(-1)) and to increase with relative kinetic energy (or temperature, T) to 2 x 10(-10) cm(3) s(-1) at 30000 K, has been measured down to 23 K. The results show that k also increases at low T (3.2 x 10(-11) cm(3) s(-1) at 23 K) which is interpreted as being due to the formation of a long-lived complex in which electronic start curve crossings occur. C1 NOAA,ENVIRONM RES LAB,BOULDER,CO 80303. RP LeGarrec, JL (reprint author), UNIV RENNES 1,UMR,PALMS ASTROCHIM EXPTL,CAMPUS BEAULIEU,F-35042 RENNES,FRANCE. NR 16 TC 5 Z9 5 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 16 PY 1997 VL 270 IS 1-2 BP 66 EP 70 DI 10.1016/S0009-2614(97)00331-X PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WZ410 UT WOS:A1997WZ41000010 ER PT J AU Faeder, J Delaney, N Maslen, PE Parson, R AF Faeder, J Delaney, N Maslen, PE Parson, R TI Charge flow and solvent dynamics in the photodissociation of cluster ions: A nonadiabatic molecular dynamics study of I-2(-)center dot Ar-n SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ELECTRON-TRANSFER; RECOMBINATION; TRANSITIONS; SOLVATION; ENERGY AB Experimental studies of photodissociation in I-2(-). Ar-n clusters have shown a rapid onset of caging for n > 10 and bimodal photofragment distributions in both dissociation and recombination channels. We simulate and interpret these results using a Hamiltonian that accounts for the strong perturbation of the solute electronic structure by the solvent, The high-mass products in the recombination channel are identified with excited state recombination, The two classes of dissociation products are identified with ejection of either a neutral I atom or an I- ion from the cluster, with the latter mechanism driven by the negative polarizability of the excited electronic state. (C) 1997 Elsevier Science B.V. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO 80309. RP Faeder, J (reprint author), UNIV COLORADO,JILA,BOULDER,CO 80309, USA. NR 29 TC 53 Z9 53 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 16 PY 1997 VL 270 IS 1-2 BP 196 EP 205 DI 10.1016/S0009-2614(97)00335-7 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WZ410 UT WOS:A1997WZ41000033 ER PT J AU Ravishankara, AR AF Ravishankara, AR TI Heterogeneous and multiphase chemistry in the troposphere SO SCIENCE LA English DT Article ID SULFURIC-ACID; ATMOSPHERIC CHEMISTRY; HYDROGEN-PEROXIDE; REACTIVE UPTAKE; WATER-VAPOR; FORMIC-ACID; CLOUDS; ICE; AEROSOLS; CLONO2 AB Heterogeneous and multiphase reactions on solids and in liquids, respectively, have the potential to play a major role in determining the composition ai the gaseous troposphere and should be included in models for understanding this region and assessing the effects of anthropogenic emissions. Making a distinction between reactions on solids (heterogeneous reactions) and those occurring in liquid droplets (multiphase reactions) is convenient for understanding, describing, and including them in models of the troposphere. Frameworks are available for including multiphase reactions in numerical models, but they do not yet exist for heterogeneous reactions. For most of these reactions, water not only provides the medium but it is also a reactant. Other substrates such as sulfate and organic and sea-salt aerosols may also be important, but their effects cannot currently be accurately assessed because of a Lack of information on their abundance, nature, and reactivities. Our ability to accurately predict the composition of the troposphere will depend on advances in understanding the microphysics of particle formation, laboratory investigations of heterogeneous and multiphase reactions, and collection of field data on tropospheric particles. C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Ravishankara, AR (reprint author), NOAA,AERON LAB,ENVIRONM RES LABS,325 BROADWAY,BOULDER,CO 80303, USA. RI Ravishankara, Akkihebbal/A-2914-2011 NR 71 TC 409 Z9 429 U1 8 U2 143 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 16 PY 1997 VL 276 IS 5315 BP 1058 EP 1065 DI 10.1126/science.276.5315.1058 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WZ225 UT WOS:A1997WZ22500027 ER PT J AU Mahlman, JD AF Mahlman, JD TI Dynamics of transport processes in the upper troposphere SO SCIENCE LA English DT Article ID GENERAL-CIRCULATION MODEL; STRATOSPHERE; N2O; EXCHANGE; WAVES AB A number of key problems in atmospheric chemistry are shaped by the strength and character of the various mechanisms acting to move and mix air in the upper troposphere. These transport processes are examined from a mechanistic perspective, with primary emphasis on the tropopause and middle-troposphere regions in the extratropics. The roles of vertical and horizontal transport ''barriers'' are explored, including the processes by which such barriers are created and are overcome. These transport considerations lead to a hypothesis concerning the processes that shape the tropopause itself. Some perspectives are offered on the still immature subject of transport in the upper troposphere of the tropics. RP Mahlman, JD (reprint author), NOAA,GEOPHYS FLUID DYNAM LAB,BOX 308,PRINCETON,NJ 08542, USA. NR 34 TC 31 Z9 31 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 16 PY 1997 VL 276 IS 5315 BP 1079 EP 1083 DI 10.1126/science.276.5315.1079 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WZ225 UT WOS:A1997WZ22500030 ER PT J AU Duewer, DL Currie, LA Reeder, DJ Leigh, SD Filliben, JJ Liu, HK Mudd, JL AF Duewer, DL Currie, LA Reeder, DJ Leigh, SD Filliben, JJ Liu, HK Mudd, JL TI Interlaboratory comparison of autoradiographic DNA profiling measurements .4. Protocol effects SO ANALYTICAL CHEMISTRY LA English DT Article AB The observed total interlaboratory uncertainty in restriction fragment length polymorphism (RFLP) measurements is sufficiently small to be of little significance given current forensic needs, However, as the number of RFLP data increase, further reduction in the total uncertainty could help minimize the resources required to evaluate potential profile matches, The large number of data available enable quantitative estimation of the within-laboratory imprecision and among-laboratory bias contributions to the total uncertainty, Some small but consistent among-laboratory measurement biases can be attributed to specific procedural or materials differences, The bias direction is often fragment-specific and thus unpredictable for unknown samples, Actions that would minimize currently recognized sources of interlaboratory bias include the following: (1) all laboratories should use the same algorithm for data interpolation, (2) all laboratories should use the same sizing ladders, (3) each laboratory should prepare control DNA and sample DNA in the same manner and with the identical reagents, (4) all laboratories should adopt a uniform policy on ethidium bromide use, anal (5) all laboratories should adopt the same control DNA sizing acceptability criteria. C1 NIST,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. NIST,COMP & APPL MATH LAB,GAITHERSBURG,MD 20899. FED BUR INVEST ACAD,CTR FORENS SCI RES & TRAINING,LAB DIV,QUANTICO,VA 22135. RI Duewer, David/B-7410-2008 NR 24 TC 17 Z9 18 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 15 PY 1997 VL 69 IS 10 BP 1882 EP 1892 DI 10.1021/ac961070k PG 11 WC Chemistry, Analytical SC Chemistry GA WX861 UT WOS:A1997WX86100012 PM 9164161 ER PT J AU YvonLewis, SA Butler, JH AF YvonLewis, SA Butler, JH TI The potential effect of oceanic biological degradation on the lifetime of atmospheric CH3Br SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID METHYL-BROMIDE AB We use a global, coupled, ocean-atmosphere box model to examine the potential effect that biological degradation and its distribution can have on the lifetime of atmospheric CH3Br. The results of this study show that both the value of the oceanic degradation rate constant and its geographic distribution are important in determining the calculated atmospheric lifetime. The best estimate of the partial lifetime of atmospheric CH3Br with respect to oceanic loss now comes to 1.8 - 1.9 y with a full possible range of 1.1 - 3.9 y, which, together with other, non-oceanic losses, yields a total atmospheric lifetime of 0.7 y (0.6 - 0.9 y). A subsequent revision of the budget for atmospheric CH3Br indicates that estimated sinks of CH3Br today exceed estimated sources by about 70 Gg y(-1). C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP YvonLewis, SA (reprint author), NOAA,CLIMATE MONITORING & DIAGNOST LAB,325 BROADWAY RECG1,BOULDER,CO 80303, USA. RI Yvon-Lewis, Shari/E-4108-2012 OI Yvon-Lewis, Shari/0000-0003-1378-8434 NR 18 TC 62 Z9 66 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 1997 VL 24 IS 10 BP 1227 EP 1230 DI 10.1029/97GL01090 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WZ425 UT WOS:A1997WZ42500018 ER PT J AU Rao, MV Gardner, JA Chi, PH Holland, OW Kelner, G Kretchmer, J Ghezzo, M AF Rao, MV Gardner, JA Chi, PH Holland, OW Kelner, G Kretchmer, J Ghezzo, M TI Phosphorus and boron implantation in 6H-SiC SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID STOICHIOMETRIC DISTURBANCES; COMPOUND SEMICONDUCTORS; ION-IMPLANTATION; SILICON-CARBIDE; DIFFUSION; PROFILES; DISTRIBUTIONS AB Phosphorus and boron ion implantations were performed at various energies in the 50 keV-4 MeV range. Range statistics of P+ and B+ were established by analyzing the as-implanted secondary ion mass spectrometry depth profiles. Anneals were conducted in the temperature range of 1400-1700 degrees C using either a conventional resistive heating ceramic processing furnace or a microwave annealing station. The P implant was found to be stable at any annealing temperature investigated, but the B redistributed during the annealing process. The implant damage is effectively annealed as indicated by Rutherford backscattering measurements. For the 250 keV/1.2x10(15) cm(-2) P implant, annealed at 1600 degrees C for 15 min, the measured donor activation at room temperature is 34% with a sheet resistance of 4.8x10(2) Omega/square. The p-type conduction could not be measured for the B implants. (C) 1997 American Institute of Physics. C1 NIST,GAITHERSBURG,MD 20899. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. USN,RES LAB,WASHINGTON,DC 20375. GE CO,CORP RES & DEV,SCHENECTADY,NY 12301. RP Rao, MV (reprint author), GEORGE MASON UNIV,DEPT ELECT & COMP ENGN,FAIRFAX,VA 22030, USA. NR 38 TC 46 Z9 46 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1997 VL 81 IS 10 BP 6635 EP 6641 DI 10.1063/1.365236 PG 7 WC Physics, Applied SC Physics GA WZ575 UT WOS:A1997WZ57500011 ER PT J AU Shafi, KVPM Gedanken, A Goldfarb, RB Felner, I AF Shafi, KVPM Gedanken, A Goldfarb, RB Felner, I TI Sonochemical preparation of nanosized amorphous Fe-Ni alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT International Alloy Conference (IAC1) CY JUN, 1996 CL ATHENS, GREECE ID IRON; INVAR AB Nanosized amorphous alloy powders of Fe20Ni80, Fe40Ni60, and Fe60Ni40 sonochemical decomposition of solutions of volatile organic precursors, Fe(CO)(5) and Ni(CO)(4) in decalin, under an argon pressure of 100 to 150 kPa at 273 K. Magnetic susceptibility of Fe40Ni60 and Fe60Ni40 indicates blocking temperatures of 35 K and a magnetic particle size of about 6 nm. Thermogravimetric measurements of Fe20Ni80 give Curie temperatures of 322 degrees C for amorphous and 550 degrees C for crystallized forms. Differential scanning calorimetry exhibits an endothermic transition at 335 degrees C from a combination of the magnetic phase transition and alloy crystallization. The Mossbauer spectrum of crystallized Fe20Ni80 shows a sextet pattern with a hyperfine field of 25.04 T. (C) 1997 American Institute of Physics. C1 BAR ILAN UNIV,DEPT CHEM,IL-52900 RAMAT GAN,ISRAEL. NATL INST STAND & TECHNOL,DIV ELECTROMAGNET TECHNOL,BOULDER,CO 80303. RI Goldfarb, Ronald/A-5493-2011 OI Goldfarb, Ronald/0000-0002-1942-7974 NR 25 TC 74 Z9 76 U1 1 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1997 VL 81 IS 10 BP 6901 EP 6905 DI 10.1063/1.365250 PG 5 WC Physics, Applied SC Physics GA WZ575 UT WOS:A1997WZ57500051 ER PT J AU Lee, YY Leone, SR Champkin, P Kaltsoyannis, N Price, SD AF Lee, YY Leone, SR Champkin, P Kaltsoyannis, N Price, SD TI Laser photofragmentation and collision-induced reactions of SiF22+ and SiF32+ SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INDUCED DISSOCIATION REACTIONS; CHARGE-TRANSFER REACTIONS; IONIZATION CROSS-SECTIONS; SINGLE-ELECTRON CAPTURE; RARE-GASES; MOLECULAR DICATIONS; AB-INITIO; ENERGY; IONS; PHOTODISSOCIATION AB Laser photofragmentation processes of the doubly charged ions SiF22+ and SiF32+ are studied at 1064, 532, and 355 nm. The observed photoproducts are compared with those of the reaction pathways induced by the collisions of these dications with the rare gases. Photodissociation, via absorption of a single photon occurs readily for both dications, and the photoion yields are dominated by the products of neutral-loss pathways: SiF2+ from SiF22+ and SiF22+ from SiF32+. A minor contribution from photoinduced charge separation is also observed. For SiF22+, a neutral-loss pathway forming the atomic dication Si2+ is also detected at higher photon energies. The excitation energy required for this fragmentation process is determined to be 2.2 +/- 0.2 eV. Collisions of SiF22+ and SiF32+ with He and Ne are also dominated by neutral-loss reactions, With the heavier rare gases, charge transfer is exothermic and dominates the product ion yield, although neutral-loss reactions still occur. Interpretation of the charge transfer results using Landau-Zener theory suggests that two electronic states of SiF22+, lying at 31.0 +/- 0.5 eV and 35.5 +/- 0.5 eV above the ground state of the neutral molecule, are present in the dication beam. Ab initio calculations reveal SiF32+ adopts an equilibrium geometry of C-2v symmetry with one elongated bond. Hence, electron capture by SiF32+ results in the formation of SiF3+ in an energetically unfavorable conformation. By taking account of these geometry differences in the Landau-Zener algorithm, a satisfactory rationalization of the ion yields from the charge transfer reactions of SiF32+ is achieved. (C) 1997 American Institute of Physics. C1 NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. UNIV LONDON UNIV COLL,DEPT CHEM,LONDON WC1H 0AJ,ENGLAND. RI Price, Stephen/C-2398-2008; OI Kaltsoyannis, Nikolas/0000-0003-0293-5742 NR 58 TC 19 Z9 19 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 1997 VL 106 IS 19 BP 7981 EP 7994 DI 10.1063/1.473809 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WZ032 UT WOS:A1997WZ03200009 ER PT J AU Flosadottir, AH Larsen, JC Smith, JT AF Flosadottir, AH Larsen, JC Smith, JT TI Motional induction in North Atlantic circulation models SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID INDUCED ELECTROMAGNETIC-FIELDS; ELECTRIC-FIELD; MAGNETIC-FIELDS; LOW-FREQUENCY; OCEAN; SCALE; POROSITY; SEA; SEDIMENTS; RESISTIVITY AB Motionally induced voltage differences provide one of the few observation methods sensitive to fluctuations of large-scale ocean transports. However, uncertainties of interpretation have impeded widespread oceanographic use of voltages measured on open-ocean cables. To resolve these uncertainties, we have developed a numerical simulation of the flow-induced voltages in general circulation models. The model includes the effects of flow meandering, the spatial and temporal variations of seawater temperature and salinity, three-dimensional Earth models with realistic sediment conductances, and the full physics applicable to the large-scale, long-period circulation when self-induction may be neglected. For the oceanographic input, we used the World Ocean Circulation Experiment Community Modeling Effort's model, which simulates the wind-driven and thermohaline circulation in the North Atlantic using mean monthly winds and realistic topography with resolution permitting mesoscale eddies. The results are in good agreement with the experimental cable calibration results from the Straits of Florida and with the Mid-Ocean Dynamics Experiment. We find less influence of large-scale electric current loops on the seafloor horizontal electric field than has previously been feared, our results supporting a local relationship of the seafloor electric field and ocean transport and the interpretation of seafloor horizontal electric field measurements in terms of local transport over much of the North Atlantic basin. C1 NOAA,PACIFIC MARINE ENVIRONM LAB,SEATTLE,WA 98115. UNIV WASHINGTON,DEPT GEOPHYS,SEATTLE,WA 98195. NR 73 TC 32 Z9 33 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAY 15 PY 1997 VL 102 IS C5 BP 10353 EP 10372 DI 10.1029/96JC03603 PG 20 WC Oceanography SC Oceanography GA XA569 UT WOS:A1997XA56900002 ER PT J AU Lewis, JM Martin, WJ Guinasso, NL AF Lewis, JM Martin, WJ Guinasso, NL TI Bowen ratio estimates in return flow over the Gulf of Mexico SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID COLD-AIR OUTBREAKS AB The Bowen ratio (and associated turbulent fluxes at the ocean-air interface) has been estimated over the Gulf of Mexico's continental shelf. These estimates are time-averaged values during the outflow phase of a particular return flow event. The study uses standard buoy data and oceanic soundings from the Louisiana-Texas Shelf Physical Oceanography Program (LATEX). Since the buoys are not equipped with water vapor sensors, the latent heat flux is determined indirectly. The calculation is made possible by combining the buoy data with a one-dimensional oceanic slab model and climatological estimates of net radiation. The application also requires a locally isothermal ocean. Estimates have been made for the return flow event of November 3-12, 1992, which exhibited maximum ocean-air temperature differences of similar to 10 degrees C. During a 2 day period when the ocean-air differences were near their maximum and when mixing extended to the seafloor beneath the buoy sites, the Bowen ratio is found to be 0.38 +/- 0.06 (0.35 +/- 0.08) at buoy sites at depths of 14 (24) m. The corresponding estimates of sensible and latent heat flux are 115 +/- 7 (115 +/- 7) and 302 +/- 48 (329 +/- 75) W m(-2), respectively. These values compare favorably with results from other field programs that used bulk aerodynamic methods to estimate turbulent fluxes in cold air outflow. The methodology appears to be generally applicable to return flow events in the Gulf of Mexico. C1 TEXAS A&M UNIV,COLLEGE STN,TX 77845. UNIV OKLAHOMA,COOPERAT INST MESOSCALE METEOROL STUDIES,NORMAN,OK 73019. RP Lewis, JM (reprint author), NOAA,NATL SEVERE STORMS LAB,NORMAN,OK 73069, USA. RI Guinasso, Norman/D-3567-2012 OI Guinasso, Norman/0000-0003-2271-8550 NR 19 TC 3 Z9 3 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAY 15 PY 1997 VL 102 IS C5 BP 10535 EP 10544 DI 10.1029/97JC00048 PG 10 WC Oceanography SC Oceanography GA XA569 UT WOS:A1997XA56900013 ER PT J AU Ralph, FM Neiman, PJ Keller, TL Levinson, D Fedor, L AF Ralph, FM Neiman, PJ Keller, TL Levinson, D Fedor, L TI Observations, simulations, and analysis of nonstationary trapped lee waves SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID PULSED DOPPLER LIDAR; MOUNTAIN WAVES; MOMENTUM FLUX; AIR-FLOW; AIRCRAFT MEASUREMENTS; WIND PROFILERS; GRAVITY-WAVES; VHF RADAR; PRECIPITATION; TROPOSPHERE AB Although considerable understanding of mountain waves has been gained with the aid of the steady-state assumption, it is clear that mountain waves evolve over time. Group velocity arguments indicate that this evolution can occur in less than 1 h. This study uses observations of trapped lee waves to measure the rate at which their horizontal wavelengths change, including a detailed analysis of two events in which such changes are clearly documented. In one case, Doppler lidar observations show a steady increase in horizontal wavelength of 6% h(-1) over 4 h and clearly illustrates the relationship between the wave clouds and wave motions. In a second case, visible satellite imagery reveals an increase in wavelength of 14% h(-1), which is related to temporal changes in vertical air motions measured by wind profilers within the wave field. Hourly vertical profiles of wind and virtual temperature measured by radio acoustic sounding systems (RASS) and wind profilers reveal important changes in the wave environment. These data were used to initialize a two-dimensional nonlinear nonhydrostatic numerical model with soundings representing five times over 8 h. Each simulation produced trapped lee waves. The simulations support the conclusion that the observed increase in wavelength resulted from changes in the wave environment. Uncertainty in the predicted wavelength due to using measurements within the trapped lee waves as initial conditions is shown to be small in this case. The wind profiler and RASS measurement accuracies are adequate to measure changes leading to trapped lee wave nonstationarity. The results from these two case studies are combined with evidence of nonstationarity found in earlier papers and additional events documented here using visible satellite imagery. These 24 observations of nonstationarity indicate that the horizontal wavelength of trapped lee waves can change by as much as 30% h(-1). The average of all events, most of which occurred at midday, is a 9% h(-1) temporal increase. It is suggested that the deepening of the mixed layer thins the elevated stable layer that is a key part of the waveguide and that this thinning causes the systematic temporal increase of the horizontal wavelength. While this study focused on trapped lee waves, it can be inferred that vertically propagating waves can also change significantly over a few hours. Because aircraft measurements of vertical momentum Aux profiles typically require 2-5 h to complete, and stationarity is required over that time, it is recommended that steadiness should be measured rather than assumed in such studies. C1 NCAR,RES APPLICAT PROGRAM,BOULDER,CO. UNIV COLORADO,NOAA,CIRES,BOULDER,CO 80309. RP Ralph, FM (reprint author), NOAA,ERL,ETL,MAIL CODE R-E-ET7,325 BROADWAY,BOULDER,CO 80303, USA. NR 72 TC 68 Z9 71 U1 4 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 15 PY 1997 VL 54 IS 10 BP 1308 EP 1333 DI 10.1175/1520-0469(1997)054<1308:OSAAON>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WZ203 UT WOS:A1997WZ20300002 ER PT J AU Kidder, LH Levin, IW Lewis, EN Kleiman, VD Heilweil, EJ AF Kidder, LH Levin, IW Lewis, EN Kleiman, VD Heilweil, EJ TI Mercury cadmium telluride focal-plane array detection for mid-infrared Fourier-transform spectroscopic imaging SO OPTICS LETTERS LA English DT Article ID MICROSCOPY AB By combining step-scan Fourier-transform Michelson interferometry, an infrared microscope, and mercury cadmium telluride focal-plane array image detection we have constructed a mid-infrared spectroscopic imaging system that simultaneously records high-fidelity images and spectra of materials from 3500 to 900 cm(-1) (2.8 to 11 mu m) at a variety of spectral resolutions. The fidelity of the spectral images is determined by the pixel number density of the focal-plane array. Step-scan imaging principles and instrument design details are outlined. Spatial resolution measurements and infrared chemical imaging examples are presented, and the results are discussed with respect to implications for chemical analysis of biosystems and composite materials. (C) 1997 Optical Society of America. C1 NIDDKD,CHEM PHYS LAB,NIH,BETHESDA,MD 20892. NIST,OPT TECHNOL DIV,GAITHERSBURG,MD 20899. RI Kleiman, Valeria/H-7818-2013 OI Kleiman, Valeria/0000-0002-9975-6558 NR 14 TC 52 Z9 52 U1 2 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 15 PY 1997 VL 22 IS 10 BP 742 EP 744 DI 10.1364/OL.22.000742 PG 3 WC Optics SC Optics GA XA242 UT WOS:A1997XA24200027 PM 18185647 ER PT J AU Ye, J Ma, LS Day, T Hall, JL AF Ye, J Ma, LS Day, T Hall, JL TI Highly selective terahertz optical frequency comb generator (vol 22, pg 301, 1997) SO OPTICS LETTERS LA English DT Correction, Addition C1 NATL INST STAND & TECHNOL,BOULDER,CO 80309. RP Ye, J (reprint author), UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309, USA. RI Ye, Jun/C-3312-2011 NR 1 TC 6 Z9 6 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 15 PY 1997 VL 22 IS 10 BP 746 EP 746 DI 10.1364/OL.22.000746 PG 1 WC Optics SC Optics GA XA242 UT WOS:A1997XA24200029 ER PT J AU WongNg, W Cook, LP Greenwood, W Jiang, F AF WongNg, W Cook, LP Greenwood, W Jiang, F TI Subsolidus and melting phase relationships of the PbOx-CaO-CuO system in air SO PHYSICA C LA English DT Article DE PbOx-CaO-CuO; superconductor related system; phase diagrams; topological melting relationships; primary phase fields ID EQUILIBRIA; DIAGRAM AB Phase equilibrium studies of the PbOx-CaO-CuO system were conducted from the subsolidus at 770 degrees C to the melting of Ca2CuO3 at 1034 degrees C. No ternary oxide compounds were found. Twelve isothermal sections and a liquidus diagram outlining the primary phase fields are presented, At 770 degrees C, in the subsolidus, Ca2PbO4 was found to be in equilibrium with Ca2CuO3, CaO, PbOx and CuO. The eutectic melting temperature is approximate to 780 degrees C, and the eutectic melting reaction is: PbO + Ca2PbO4 + CuO --> liquid. Two additional ternary melting reactions were characterized. Above 1034 degrees C, the only solid compounds remaining are CaO and CuO. (C) 1997 Elsevier Science B.V. C1 UNIV MARYLAND,DEPT GEOL,COLLEGE PK,MD 20742. RP WongNg, W (reprint author), NIST,DIV CERAM,GAITHERSBURG,MD 20899, USA. NR 18 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 15 PY 1997 VL 279 IS 1-2 BP 31 EP 38 DI 10.1016/S0921-4534(97)00078-6 PG 8 WC Physics, Applied SC Physics GA XG695 UT WOS:A1997XG69500004 ER PT J AU Carter, AC Bouldin, CE Kemner, KM Bell, MI Woicik, JC Majetich, SA AF Carter, AC Bouldin, CE Kemner, KM Bell, MI Woicik, JC Majetich, SA TI Surface structure of cadmium selenide nanocrystallites SO PHYSICAL REVIEW B LA English DT Article ID ABSORPTION FINE-STRUCTURE; SEMICONDUCTOR CLUSTERS; AQUEOUS-SOLUTIONS; TRANSITION; COMPLEXES; SULFIDE; FIELD AB Extended x-ray-absorption fine structure (EXAFS), Fourier-transform infrared absorption (FTIR), and elemental analysis were used on a variety of CdSe nanocrystallites (NC's) to study surface structure. All CdSe NC's were grown by standard inverse micelle techniques. Two sets of NC's samples were made. One set was made so that only the size of the NC's was varied, while the surface treatment was kept the same. The other set was made so that only the surface treatment was varied, while the size distribution was kept the same. For the EXAFS experiments, reference compounds similar in structure were measured. FTIR found surface Cd atoms to be passivated by pyridines and water groups. Fourier-filtered first-shell Cd EXAFS also supports the existence of water groups attached to the surface Cd atoms. The lack of any SeO and Si(CH3)(3) in the FTIR signal indicates that most surface Se atoms have unterminated bonds. Fourier-filtered first-shell Se EXAFS spectra indicate that Se has only Cd as its first-nearest neighbor, and that the coordination number is reduced from the bulk value, suggesting surface Se atoms are unpassivated. Our data support the existence of surface Se lone-pair orbitals that can trap an optically excited hole. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20818. CARNEGIE MELLON UNIV,PITTSBURGH,PA 15213. RP Carter, AC (reprint author), USN,RES LAB,WASHINGTON,DC 20357, USA. RI Majetich, Sara/B-1022-2015 OI Majetich, Sara/0000-0003-0848-9317 NR 31 TC 56 Z9 56 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1997 VL 55 IS 20 BP 13822 EP 13828 DI 10.1103/PhysRevB.55.13822 PG 7 WC Physics, Condensed Matter SC Physics GA XD170 UT WOS:A1997XD17000073 ER PT J AU Yang, MX Kash, PW Sun, DH Flynn, GW Bent, BE Holbrook, MT Bare, SR Fischer, DA Gland, JL AF Yang, MX Kash, PW Sun, DH Flynn, GW Bent, BE Holbrook, MT Bare, SR Fischer, DA Gland, JL TI Chemistry of chloroethylenes on Cu(100): Bonding and reactions SO SURFACE SCIENCE LA English DT Article DE alkenes; chemisorption; copper; halides; near edge extended X-ray absorption fine structure (NEXAFS); surface chemical reaction; thermal desorption spectroscopy; work function measurements ID ELECTRON-ENERGY-LOSS; ABSORPTION FINE-STRUCTURE; METHYL HALIDES CL; SHAPE RESONANCES; LOSS SPECTRA; CU(111); ADSORPTION; SURFACES; PT(111); LENGTHS AB The bonding and reactions of chloroethylenes (vinyl chloride, trans- and cis-dichloroethylene, trichloroethylene) on a Cu(100) surface have been investigated by temperature-programmed desorption and reaction, near-edge X-rap absorption fine structure (NEXAFS) studies and measurements of changes of the surface work function. The monolayer molecules adsorb molecularly intact at 95 K via pi coordination. The molecules orient with their molecular planes parallel to the surface with little increase (<0.02 Angstrom) in the C-C bond distance compared with the gas phase values. The degree of thermal dissociation increases with the extent of halogenation, and no chlorine is present in the hydrocarbon reaction products liberated from the surface. Both cis- and trans-1,2-chloroethylene produce acetylene and a small amount of benzene, while dissociation of trichloroethylene generates acetylene and deposits a carbon residue on the surface. Vinyl chloride desorbs from Cu(100) without reaction. (C) 1997 Elsevier Science B.V. C1 DOW CHEM CO USA,MIDLAND,MI 48674. BROOKHAVEN NATL LAB,NATL INST STAND & TECHNOL,NSLS,UPTON,NY 11973. UNIV MICHIGAN,DEPT CHEM,ANN ARBOR,MI 48109. RP Yang, MX (reprint author), COLUMBIA UNIV,DEPT CHEM,NEW YORK,NY 10027, USA. NR 31 TC 35 Z9 35 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 15 PY 1997 VL 380 IS 2-3 BP 151 EP 164 DI 10.1016/S0039-6028(96)01002-3 PG 14 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA XF843 UT WOS:A1997XF84300009 ER PT J AU Lai, NC Korsmeyer, KE Katz, S Holts, DB Laughlin, LM Graham, JB AF Lai, NC Korsmeyer, KE Katz, S Holts, DB Laughlin, LM Graham, JB TI Hemodynamics and blood properties of the shortfin Mako shark (Isurus oxyrinchus) SO COPEIA LA English DT Article ID ELASMOBRANCH FISHES; RAINBOW-TROUT C1 SCRIPPS INST OCEANOG, BIOMED & MARINE BIOL RES DIV, LA JOLLA, CA 92093 USA. NATL MARINE FISHERIES SERV, SW FISHERIES SCI CTR, LA JOLLA, CA 92038 USA. CALIF DEPT FISH & GAME, LONG BEACH, CA 90802 USA. RP Lai, NC (reprint author), SCRIPPS INST OCEANOG, CTR MARINE BIOTECHNOL, LA JOLLA, CA 92093 USA. OI Korsmeyer, Keith/0000-0003-4457-3495 NR 19 TC 17 Z9 17 U1 0 U2 5 PU AMER SOC ICHTHYOLOGISTS & HERPETOLOGISTS PI MIAMI PA MAUREEN DONNELLY, SECRETARY FLORIDA INT UNIV BIOLOGICAL SCIENCES, 11200 SW 8TH STREET, MIAMI, FL 33199 USA SN 0045-8511 EI 1938-5110 J9 COPEIA JI Copeia PD MAY 13 PY 1997 IS 2 BP 424 EP 428 DI 10.2307/1447765 PG 5 WC Zoology SC Zoology GA XA761 UT WOS:A1997XA76100022 ER PT J AU Sandwell, DT Smith, WHF AF Sandwell, DT Smith, WHF TI Marine gravity anomaly from Geosat and ERS 1 satellite altimetry SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID TOPEX/POSEIDON ALTIMETRY; SEASAT; OCEAN; RESOLUTION; ATLANTIC; ACCURACY; BATHYMETRY; TOPOGRAPHY; CURVATURE; SHIPBOARD AB Closely spaced satellite altimeter profiles collected during the Geosat Geodetic Mission (similar to 6 km) and the ERS 1 Geodetic Phase (8 km) are easily converted to grids of vertical gravity gradient and gravity anomaly. The long-wavelength radial orbit error is suppressed below the noise level of the altimeter by taking the along-track derivative of each profile. Ascending and descending slope profiles are then interpolated onto separate uniform grids. These four grids are combined to form comparable grids of east and north vertical deflection using an iteration scheme that interpolates data gaps with minimum curvature. The vertical gravity gradient is calculated directly from the derivatives of the vertical deflection grids, while Fourier analysis is required to construct gravity anomalies from the two vertical deflection grids. These techniques are applied to a combination of high-density data from the dense mapping phases of Geosat and ERS 1 along with lower-density but higher-accuracy profiles from their repeat orbit phases. A comparison with shipboard gravity data shows the accuracy of the satellite-derived gravity anomaly is about 4-7 mGal for random skip tracks. The accuracy improves to 3 mGal when the ship track follows a Geosat Exact Repeat Mission track line. These data provide the first view of the ocean floor structures in many remote areas of the Earth. Some applications include inertial navigation, prediction of seafloor depth, planning shipboard surveys, plate tectonics, isostasy of volcanoes and spreading ridges, and petroleum exploration. C1 NOAA, GEOSCI LAB, SILVER SPRING, MD 20910 USA. RP Sandwell, DT (reprint author), UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, INST GEOPHYS & PLANETARY PHYS, IGPP 0225, 9500 GILMAN DR, LA JOLLA, CA 92093 USA. RI Smith, Walter/F-5627-2010; OI Smith, Walter/0000-0002-8814-015X; Sandwell, David/0000-0001-5657-8707 NR 44 TC 1155 Z9 1211 U1 7 U2 60 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 10 PY 1997 VL 102 IS B5 BP 10039 EP 10054 DI 10.1029/96JB03223 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WY347 UT WOS:A1997WY34700011 ER PT J AU Woodhouse, CA AF Woodhouse, CA TI Tree-ring reconstructions of circulation indices SO CLIMATE RESEARCH LA English DT Article DE circulation indices; tree rings; climate reconstructions; Southwestern US ID NORTH-ATLANTIC OSCILLATION; SOUTHERN OSCILLATION; UNITED-STATES; WINTER TEMPERATURES; SPATIAL PATTERNS; ENSO EVENTS; CLIMATE; VARIABILITY; HEMISPHERE; INDEXES AB Generalized circulation indices, as descriptors of atmospheric circulation features, have been used to analyze the relationships between circulation and regional climates. Currently, data for such circulation indices are limited. Records for some indices extend back into the 19th century, but most are based on data that exist for less than 100 yr. Tree rings have been successfully used to extend records of circulation indices, most notably the Southern Oscillation Index. Researchers are continuing to improve reconstructions and to explore the potential of reconstructing other indices. In contrast to more general indices, it is possible to select and/or construct indices that describe circulation features important to a specific region. These regionally tailored circulation indices, along with more general indices that describe features also influencing the climate of a region, can be reconstructed from tree rings. Reconstructions can provide information about variability in atmospheric circulation and about the interactions between influential circulation features in past centuries. In this paper, an example of such a study is given in which a set of circulation indices, compiled for the southwestern U.S., is reconstructed from tree rings. This preliminary study demonstrates the potential Value of regionally tailored circulation indices and the reconstruction of these circulation indices for gaining an understanding of how circulation patterns may influence regional climates, on scales of decades to centuries. C1 UNIV ARIZONA,TREE RING RES LAB,TUCSON,AZ 85721. RP Woodhouse, CA (reprint author), NOAA,NATL GEOPHYS DATA CTR,PALEOCLIMATOL PROGRAM,325 BROADWAY,BOULDER,CO 80303, USA. NR 66 TC 5 Z9 8 U1 1 U2 1 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0936-577X J9 CLIMATE RES JI Clim. Res. PD MAY 8 PY 1997 VL 8 IS 2 BP 117 EP 127 DI 10.3354/cr008117 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA XH990 UT WOS:A1997XH99000003 ER PT J AU Shoute, LCT Huie, RE AF Shoute, LCT Huie, RE TI Reactions of triplet decafluorobenzophenone with alkenes. A laser flash photolysis study SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PATERNO-BUCHI REACTION; HYDROGEN ABSTRACTION; KETONE TRIPLETS; CHARGE-TRANSFER; PHENYL KETONES; BENZOPHENONE; PHOTOREDUCTION; MECHANISM; KINETICS; PHOTOCHEMISTRY AB Rate constants for the reactions of triplet decafluorobenzophenone ((DFB)-D-3) with 30 alkenes have been measured, with values in the range 10(7)-10(9) L mol(-1) s(-1). The rate constant increases upon substituting electron-donating groups on the double bond, whereas it decreases upon substituting electron-withdrawing groups. For cyclohexene and 2-butene, the rate constant increases with increasing methyl substitution at the double bond, suggesting that steric effects play a minor role in the reaction. Further, there is a linear correlation between log k(r) (k(r) = the second-order rate constant of the reaction of (DFB)-D-3 and alkene) and the ionization potential of the alkene. The extent of hydrogen abstraction was determined by measuring the yield of the ketyl radical. Quantum yields for ketyl radical formation, Phi(K), increase with the ionization potential and the number of activated hydrogens, nH, on the alkene. The absolute values of Phi(K) and a linear correlation between Phi(K)/nH and ionization potential suggest that hydrogen abstraction is preceded by complex formation. C1 NIST,DIV PHYS & CHEM PROPERTIES,GAITHERSBURG,MD 20899. BHABHA ATOM RES CTR,DIV CHEM,BOMBAY 400085,MAHARASHTRA,INDIA. RI Huie, Robert/A-5645-2010 NR 65 TC 3 Z9 3 U1 2 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 8 PY 1997 VL 101 IS 19 BP 3467 EP 3471 DI 10.1021/jp970061s PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WY394 UT WOS:A1997WY39400008 ER PT J AU Bilde, M Mogelberg, TE Sehested, J Nielsen, OJ Wallington, TJ Hurley, MD Japar, SM Dill, M Orkin, VL Buckley, TJ Huie, RE Kurylo, MJ AF Bilde, M Mogelberg, TE Sehested, J Nielsen, OJ Wallington, TJ Hurley, MD Japar, SM Dill, M Orkin, VL Buckley, TJ Huie, RE Kurylo, MJ TI Atmospheric chemistry of dimethyl carbonate: Reaction with OH radicals, UV spectra of CH3OC(O)OCH2 and CH3OC(O)OCH2O2 radicals, reactions of CH3OC(O)OCH2O2 with NO and NO2, and fate of CH3OC(O)OCH2O radicals SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TEMPERATURE-RANGE 240-440-K; GAS-PHASE REACTIONS; HYDROXYL RADICALS; PEROXY-RADICALS; KINETICS; SERIES; 295-K; ATOMS; SPECTROSCOPY; CF3CHCL2 AB A flash photolysis-resonance fluorescence technique was used to study the rate constant for the reaction of OH radicals with dimethyl carbonate over the temperature range 252-370 K, The rate constant exhibited a weak temperature dependence, increasing at both low and high temperature from a minimum value of approximately 3.1 x 10(-13) cm(3) molecule(-1) s(-1) near room temperature. Pulse radiolysis/transient UV absorption techniques were used to study the ultraviolet absorption spectra and kinetics of CH3OC(O)OCH2 and CH3OC(O)CH2O2 radicals at 296 K. Absorption cross sections of CH3OC(O)OCH2 and CH3OC(O)OCH2O2 at 250 nm were (3.16 +/- 0.34) x 10(-18) and (3.04 +/- 0.43) x 10(-18) cm(2) molecule(-1), respectively. Rate constants measured for the self-reactions of CH3OC(O)OCH2 and CH3OC(O)OCH2O2 radicals and reactions of CH3OC(O)OCH2O2 radicals with NO and NO2 were (5.6 +/- 1.1) x 10(-11), (1.27 +/- 0.21) x 10(-11), (1.2 +/- 0.2) x 10(-11), and (1.2 +/- 0.2) x 10(-11) cm(3) molecule(-1) s(-1), respectively. The rate constant for reaction of F atoms with dimethyl carbonate was determined by a pulse radiolysis absolute rate technique to be (6.1 +/- 0.9) x 10(-11) cm(3) molecule(-1) s(-1) A FTIR smog chamber system was used to show that, in 760 Torr of air at 296 K, CH3OC(O)OCH2O radicals are lost via three competing processes: 42 +/- 15% via reaction with O-2, 14 +/- 2% via H atom elimination, and 44 +/- 10% via decomposition and/or isomerization. Relative rate techniques were used to measure rate constants for the reactions of F atoms with CH3OC(O)OCH3, (6.4 +/- 1.4) x 10(-11) cm(3) molecule(-1) s(-1), and Cl atoms with CH3OC(O)OCH3, CH3OC(O)OCH2Cl, CH3OC(O)OCHO, and HC(O)OC(O)OCHO, (2.3 +/- 0.8) x 10(-12), (4.6 +/- 2.8) x 10(-13), (1.7 +/- 0.1) x 10(-13), and (1.7 +/- 0.1) x 10(-14) cm(3) molecule(-1) s(-1), respectively. Results are discussed in the context of the atmospheric chemistry of CH3OC(O)OCH3. C1 RISO NATL LAB,DEPT ENVIRONM SCI & TECHNOL,CHEM REACT SECT,DK-4000 ROSKILDE,DENMARK. FORD MOTOR CO,RES STAFF,DEARBORN,MI 48121. NIST,CTR CHEM PHYS,GAITHERSBURG,MD 20899. RI Kurylo, Michael/H-2201-2012; Nielsen, Ole/B-9988-2011 OI Nielsen, Ole/0000-0002-0088-3937 NR 38 TC 43 Z9 44 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 8 PY 1997 VL 101 IS 19 BP 3514 EP 3525 DI 10.1021/jp961664r PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WY394 UT WOS:A1997WY39400016 ER PT J AU Bendersky, LA Waterstrat, RM AF Bendersky, LA Waterstrat, RM TI Incommensurate structure of the phase Zr3Rh4 SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Letter DE Zr3Rh4 phase; incommensurate modulation; electron diffraction AB The crystallographic structure of the phase Zr3Rh4 has been studied by transmission electron microscopy. It was found that the phase has a basic rhombohedral lattice which is modulated by an incommensurate wave. The basic structure is isomorphous with a structure of the Pu3Pd4-type. RP Bendersky, LA (reprint author), NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899, USA. NR 7 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 5 PY 1997 VL 252 IS 1-2 BP L5 EP L7 DI 10.1016/S0925-8388(96)02417-6 PG 3 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA XE340 UT WOS:A1997XE34000002 ER PT J AU Ladner, JE Wladkowski, BD Svensson, LA Sjolin, L Gilliland, GL AF Ladner, JE Wladkowski, BD Svensson, LA Sjolin, L Gilliland, GL TI X-ray structure of a ribonuclease A-uridine vanadate complex at 1.3 angstrom resolution SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID REFINED CRYSTAL-STRUCTURE; TRANSITION-STATE ANALOGS; PANCREATIC RIBONUCLEASE; ACTIVE-SITE; NEUTRON-DIFFRACTION; SUBSTRATE BINDING; RNASE-A; STEP AB The X-ray crystal structure of a uridine vanadate-ribonuclease A complex has been determined at 1.3 Angstrom resolution. The resulting structure includes all 124 amino-acid residues, a uridine vanadate, 131 water molecules, and a single bound 2-methyl-2-propanol. Side chains of 11 surface residues showing discrete disorder were modeled with multiple conformations. The final crystallographic R factor is 0.197. Structures obtained from high-level ab initio quantum calculations of model anionic oxyvanadate compounds were used to probe the effects of starting structure on the refinement process and final structure of the penta-coordinate phosphorane analog, uridine vanadate. The least-squares refinement procedure gave rise to the same final structure of the inhibitor despite significantly different starting models. Comparison with the previously determined complex of ribonuclease A with uridine vanadate obtained from a joint X-ray/neutron analysis (6RSA) [Wlodawer, Miller & Sjolin (1983). Proc. Natl Acad. Sci. USA, 80, 3628-3631] reveals similarities in the overall enzyme structure and the relative position of the key active-site residues, His12, His119 and Lys41, but significant differences in the V-O bond distances and angles. The influence of ligand binding on the enzyme structure is assessed by a comparison of the current X-ray structure with the phosphate-free ribonuclease A structure (7RSA) [Wlodawer, Svensson, Sjolin & Gilliland (1988). Biochemistry, 27, 2705-2717]. Ligand binding alters the solvent structure, distribution and number of residues with multiple conformations, and temperature factors of the protein atoms. In fact, the temperature factors of atoms of several residues that interact with the ligand are reduced, but those of the atoms of several residues remote from the active site exhibit marked increases. C1 NATL INST STAND & TECHNOL,ROCKVILLE,MD 20850. WESTERN MARYLAND COLL,DEPT CHEM,WESTMINSTER,MD 21157. LUND UNIV,DEPT MOL BIOPHYS,CTR CHEM & CHEM ENGN,S-22100 LUND,SWEDEN. CHALMERS UNIV TECHNOL,DEPT INORGAN CHEM,S-41296 GOTHENBURG,SWEDEN. UNIV GOTHENBURG,S-41296 GOTHENBURG,SWEDEN. RP Ladner, JE (reprint author), UNIV MARYLAND,MARYLAND BIOTECHNOL INST,CTR ADV RES BIOTECHNOL,9600 GUDELSKY DR,ROCKVILLE,MD 20850, USA. RI Sjolin, Lennart/B-2619-2010 NR 47 TC 42 Z9 42 U1 0 U2 4 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD MAY 1 PY 1997 VL 53 BP 290 EP 301 DI 10.1107/S090744499601582X PN 3 PG 12 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA XB256 UT WOS:A1997XB25600008 PM 15299932 ER PT J AU Weissmuller, J Cahn, JW AF Weissmuller, J Cahn, JW TI Mean stresses in microstructures due to interface stresses: A generalization of a capillary equation for solids SO ACTA MATERIALIA LA English DT Article ID THIN-FILMS; SURFACE STRESS; CURVATURE AB We derive a general expression for the mean stress in a solid induced by the stresses of areal and linear defects such as grain boundaries and triple junction lines. The mean stress is a function of measurable stereological quantities, weighted areas of interfaces and lengths of the linear defects, not their curvatures. Generally the stress is non-hydrostatic. For anisotropic and textured microstructures, the mean stress depends on stereological moments of the interface orientation distribution function, but otherwise it is independent of the geometry of the microstructure. In two limiting cases, isolated spherical particles (in a matrix or not) and layer structures, the solution for the stress reduces to results which have been derived previously. These solutions can be used to determine average interface stresses from experimental lattice constant data. Although the specific interface area is always the important quantity in this relation, for the spheres this area/volume reduces to the particle curvatures commonly used in the literature for many microstructures. (C) 1997 Acta Metallurgica Inc. C1 NATL INST STAND & TECHNOL,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899. RI Weissmuller, Jorg/C-3967-2009 OI Weissmuller, Jorg/0000-0002-8958-4414 NR 37 TC 148 Z9 150 U1 4 U2 38 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY PY 1997 VL 45 IS 5 BP 1899 EP 1906 DI 10.1016/S1359-6454(96)00314-X PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA WX194 UT WOS:A1997WX19400009 ER PT J AU Fayer, R Farley, CA Lewis, EJ Trout, JM Graczyk, TK AF Fayer, R Farley, CA Lewis, EJ Trout, JM Graczyk, TK TI Potential role of the Eastern oyster, Crassostrea virginica, in the epidemiology of Cryptosporidium parvum SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article AB Oysters were placed in an aquarium containing artificial seawater, and Cryptosporidium parvum oocysts were added. Oocysts were later found in the gill washings, hemocytes, and gut contents af the oysters, Hemocytes containing oocysts were intubated into four mice. C. parvum stages developed in the ileal epithelia of all of the mice, indicating that the oocysts in the hemocytes remained infective. C1 NATL MARINE FISHERIES SERV,COOPERAT OXFORD LAB,NOAA,OXFORD,MD 21654. JOHNS HOPKINS UNIV,SCH HYG & PUBL HLTH,DEPT MOL MICROBIOL & IMMUNOL,BALTIMORE,MD 21205. RP Fayer, R (reprint author), ARS,IMMUNOL & DIS RESISTANCE LAB,USDA,BELTSVILLE,MD 20705, USA. NR 14 TC 51 Z9 52 U1 2 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD MAY PY 1997 VL 63 IS 5 BP 2086 EP 2088 PG 3 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA WX361 UT WOS:A1997WX36100071 PM 16535617 ER PT J AU Petrov, KP Waltman, S Dlugokencky, EJ Arbore, M Fejer, MM Tittel, FK Hollberg, LW AF Petrov, KP Waltman, S Dlugokencky, EJ Arbore, M Fejer, MM Tittel, FK Hollberg, LW TI Precise measurement of methane in air using diode-pumped 3.4-mu m difference-frequency generation in PPLN SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID LASER; SPECTROMETER; NO2 AB Fast, accurate measurement of the methane mixing ratio in natural air samples using a compact solid-state 3.4-mu m difference-frequency spectrometer is reported. The spectrometer employed bulk periodically poled lithium niobate (PPLN) pumped by a solitary diode laser at 808 nm and a diode-pumped monolithic ring Nd:YAC laser at 1064 nm, and a 300 cm(3) volume multi-pass absorption cell with an 18m path length. The methane mixing ratio was determined by comparing the direct optical absorption measured in the sample with that measured in a reference gas at 100 torr and room temperature. Relative accuracy of better than 1 ppb (parts in 10(9), by mole fraction) was achieved in measurements of natural air that contained 1700-1900 ppb methane. The typical measurement time for each sample was 60 seconds. The accuracy was limited by residual interference fringes in the multi-pass cell that resulted from scattering. Without the use of reference samples, the relative accuracy was 20 ppb; it was limited by the long-term reproducibility of the spectroscopic baseline, which was affected by drift in the optical alignment coupled to changes in the ambient temperature. This work demonstrates the use of diode-pumped difference-frequency generation (DFG) in PPLN in a high-precision infrared spectrometer. Compact, room-temperature solid-state gas sensors can be built based on this technology, for accurate real-time measurements of trace gases in the 3-5 mu m spectroscopic region. C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. NOAA,CLIMATE MONITORING & DIAGNOST LAB,BOULDER,CO 80303. STANFORD UNIV,EDWARD L GINZTON LAB,STANFORD,CA 94305. RP Petrov, KP (reprint author), RICE UNIV,RICE QUANTUM INST,HOUSTON,TX 77251, USA. NR 17 TC 50 Z9 51 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD MAY PY 1997 VL 64 IS 5 BP 567 EP 572 DI 10.1007/s003400050216 PG 6 WC Optics; Physics, Applied SC Optics; Physics GA XB494 UT WOS:A1997XB49400010 ER PT J AU Giroux, ML Shull, JM AF Giroux, ML Shull, JM TI The influence of the photoionizing radiation spectrum on metal-line ratios in LY alpha forest clouds SO ASTRONOMICAL JOURNAL LA English DT Article ID H-II REGIONS; INTERGALACTIC MEDIUM; HIGH-REDSHIFT; HELIUM ABSORPTION; SYSTEMS; QUASARS; EVOLUTION; MODELS AB Recent measurements of Si IV/C IV ratios in the high-redshift Ly alpha forest [Songaila & Cowie, AJ, 112, 335 (1996a); Savaglio et al., A&A (in press) (1997)] have opened a new window on chemical enrichment and the first generations of stars. However, the derivation of accurate Si/C abundances requires reliable ionization corrections, which are strongly dependent on the spectral shape of the metagalactic ionizing background and on the ''local effects'' of hot stars in nearby galaxies. Recent models have assumed power-law quasar ionizing backgrounds plus a decrement at 4 Ryd to account for He II attenuation in intervening clouds. However, we show that realistic ionizing backgrounds based on cosmological radiative transfer models produce more complex ionizing spectra between 1-5 Ryd that are critical to interpreting ions of Si and C. We also make a preliminary investigation of the effects of He II ionization front nonoverlap. Because the attenuation and reemission by intervening clouds enhance Si rv relative to C IV, the observed high Si IV/C rv ratios do not require an unrealistic Si overproduction [Si/C greater than or equal to 3 (Si/C).]. If the ionizing spectrum is dominated by ''local effects'' from massive stars, even larger Si IV/C Iv ratios are possible. However, unless stellar radiation dominates quasars by more than a factor of 10, we confirm the evidence for some Si overproduction by massive stars; values Si/C approximate to 2 (Si/C). fit the measurements better than solar abundances. Ultimately, an adequate interpretation of the ratios of C Iv, Si IV, and C II may require hot, collisionally ionized gas in a multiphase medium. (C) 1997 American Astronomical Society. C1 UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Giroux, ML (reprint author), UNIV COLORADO,CTR ASTROPHYS & SPACE ASTRON,DEPT ASTROPHYS PLANETARY & ATMOSPHER SCI,BOULDER,CO 80309, USA. NR 50 TC 69 Z9 69 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1997 VL 113 IS 5 BP 1505 EP 1513 DI 10.1086/118367 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WX752 UT WOS:A1997WX75200004 ER PT J AU Mehringer, DM Snyder, LE Miao, YT AF Mehringer, DM Snyder, LE Miao, YT TI Detection and confirmation of interstellar acetic acid SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, abundances; ISM, clouds; ISM, individual (Sagittarius B2[LMH); ISM, molecules; radio lines, ISM ID SAGITTARIUS B2; CLOUDS AB We have detected acetic acid (CH3COOH) in the Sgr B2 Large Molecule Heimat source using the Berkeley-Illinois-Maryland Association (BIMA) Array and the Caltech Owens Valley Radio Observatory (OVRO) Millimeter Array. With the BIMA array, we initially detected the 8(*,8)-7(*,7)(2) A blend near 90.2 GHz. The corresponding line from the E symmetry species was sought but may be blended with a line from another species. Interstellar CH3COOH was confirmed using the OVRO array, with which we detected the 9(*,9)-8(*,8) E blend near 100.9 GHz. The corresponding line from the A symmetry species was sought but was found to be blended with the 7(1)-7(0) E line of CH3SH. Our CH3COOH observations represent the first detection and confirmation of an interstellar molecule using interferometric arrays; all past detections and confirmations of new molecules have been made on the basis of single-element telescope observations. C1 UNIV ILLINOIS,DEPT ASTRON,URBANA,IL 61801. NIST,OPT TECHNOL DIV,GAITHERSBURG,MD 20899. NR 18 TC 120 Z9 120 U1 0 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1997 VL 480 IS 1 BP L71 EP & DI 10.1086/310612 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WW284 UT WOS:A1997WW28400018 ER PT J AU Malm, WC Pitchford, ML AF Malm, WC Pitchford, ML TI Comparison of calculated sulfate scattering efficiencies as estimated from size-resolved particle measurements at three national locations SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE visibility; size distribution; sulfur; extinctions ID VISIBILITY REDUCTION; INORGANIC AEROSOL; DISTRIBUTIONS; MODEL AB Size distributions and resulting optical properties of sulfur aerosols were investigated at three national parks by a Davis Rotating-drum Universal-size-cut Monitoring (DRUM) impactor. Sulfur size distribution measurements for 88, 177, and 315 consecutive time periods were made at Grand Canyon National Park during January and February 1988, Meadview, AZ during July, August, and September 1992, and at Shenandoah National Park during summer, 1990, respectively. The DRUM impactor is designed to collect aerosols with an aerodynamic diameter between 0.07 and 15.0 mu m in eight size ranges. Focused beam particle-induced X-ray emission (PIXE) analysis of the aerosol deposits produces a time history of size-resolved elemental composition of varied temporal resolution. As part of the quality assurance protocol, an interagency monitoring of protected visual environments (IMPROVE) channel A sampler collecting 0-2.5 mu m diameter particles was operated simultaneously alongside the DRUM sampler. During these sampling periods, the average sulfur mass, interpreted as ammonium sulfate, is 0.49, 2.30, and 10.36 mu g m(-3) at Grand Canyon, Meadview, and Shenandoah, respectively. The five drum stages were ''inverted'' using the Twomey (1975) scheme to give 486 size distributions, each made up of 72 discreet pairs of dC/dlog(D) and diameter (D). From these distributions mass mean diameters (D-g), geometric standard deviations (sigma(g)), and mass scattering efficiencies (e(m)) were calculated. The geometric mass mean diameters in ascending order were 0.21 mu m at Meadview, 0.32 mu m at Grand Canyon, and 0.42 mu m at Shenandoah. The corresponding sigma(g)'s were 2.1, 2.3, and 1.9. Mie theory mass scattering efficiencies calculated from dC/dlog(D) distributions for the three locations were 2.05, 2.59, and 3.81 m(2) g(-1), respectively. At Shenandoah, mass scattering efficiencies approached five but only when the mass median diameters were approximately 0.4 mu m and sigma(g)'s were about 1.5. sigma(g)'s near 1.5 were frequently measured at Shenandoah, rarely at Grand Canyon, and never during the summer at Meadview. (C) 1997 Elsevier Science Ltd. C1 NATL OCEAN & ATMOSPHER ADM,AIR RESOURCES LAB,SPECIAL OPERAT DIV,LAS VEGAS,NV 89132. RP Malm, WC (reprint author), COLORADO STATE UNIV,COOPERAT INST RES ATMOSPHERE,AIR RESOURCES DIV,NATL PK SERV,FT COLLINS,CO 80523, USA. NR 33 TC 34 Z9 38 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAY PY 1997 VL 31 IS 9 BP 1315 EP 1325 DI 10.1016/S1352-2310(96)00280-4 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA WK704 UT WOS:A1997WK70400006 ER PT J AU Hansen, ADA Polissar, AV Schnell, RC AF Hansen, ADA Polissar, AV Schnell, RC TI Airborne aerosol and black carbon measurements over the East Siberian Sea, Spring 1992 SO ATMOSPHERIC RESEARCH LA English DT Article ID POLLUTION; BARROW; AIR AB In April 1992 we performed measurements of Arctic aerosol properties from an aircraft flying over the East Siberian Sea from Cherskiy (69 degrees N, 161 degrees E) to Bennett Island (76.5 degrees N, 149 degrees E). Eight round-trip flights were made over this 1000 kilometer path, with each flight incorporating several profiling descents from approximately 4.2 km altitude to the surface. On a 10-second time base were recorded measurements of aerosol black carbon (BC), condensation nuclei (CN), air temperature and absolute barometric pressure, from which altitude was deduced. Some profiles showed considerable vertical structure with numerous temperature inversions and stratified aerosol layers. Peak BC and CN concentrations exceeded 1000 ng m(-3) and 1000 cm(-3) respectively. Occasionally, extremely clean air was found in some layers. Other descents showed stable temperature profiles, with aerosol BC and CN distributed throughout the lower 4 km of the atmosphere. In most cases, the surface temperature-inversion layer contained high concentrations of aerosol species. We conclude that the atmosphere in this remote area is strongly affected by anthropogenic emissions from distant source regions, and that the meteorological and aerosol concentration profile structures were similar to those regularly observed in the western sectors of the Arctic in springtime. (C) 1997 Elsevier Science B.V. C1 NOAA,CMDL,MAUNA LOA OBSERV,HILO,HI 96720. RUSSIAN ACAD SCI,INST ATMOSPHER PHYS,MOSCOW,RUSSIA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA. NR 20 TC 5 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD MAY PY 1997 VL 44 IS 1-2 BP 153 EP 165 DI 10.1016/S0169-8095(96)00036-1 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XH721 UT WOS:A1997XH72100013 ER PT J AU Cole, KD AF Cole, KD TI Preparative concentration and size fractionation of DNA by porous media using a combination of flow and low electric field strength SO BIOTECHNOLOGY PROGRESS LA English DT Article ID ELECTROCHROMATOGRAPHY; PROTEINS; OLIGONUCLEOTIDES AB The retention of DNA by porous media during chromatography with an applied axial electric field was investigated. DNA was retained by negative electric fields in columns packed with Sephadex G-75 and G-25. A negative field was defined as the electric field orientation in which the direction of electrophoresis was opposing the direction of buffer flow (positive electrode at the column inlet). A positive field was not effective at retaining the DNA. The electric field strength required to retain the DNA was dependent upon the buffer flow rate. The retention of DNA using Sephadex G-25, a gel filtration medium with a higher degree of cross-linking, required higher electric fields than the more porous Sephadex G-75. A dilute DNA solution was concentrated at the inlet of the chromatography bed by an electric field. Mixtures of DNA restriction fragments were used to determine size-dependent retention. DNA was size-fractionated by varying the electric field strength and flow rate. At a given electric field strength and flow rate, the lower molecular weight DNA fragments were not as strongly retained as the higher molecular weight fragments. Decreasing the flow rate or increasing the electric field strength resulted in increased retention of the lower molecular weight DNA fragments. In this manner, by selecting a specific set of conditions (packing material, flow rate, and electric field strength), the molecular weight of DNA fragments retained by the column can be adjusted. Efficient separation of high molecular weight DNA from bovine serum albumin, a protein with high electrophoretic mobility, was demonstrated using a field of 2 V/cm in a column packed with Sephadex G-75. RP Cole, KD (reprint author), NIST,DIV BIOTECHNOL,BLDG 222,ROOM A353,GAITHERSBURG,MD 20899, USA. NR 17 TC 14 Z9 14 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 8756-7938 J9 BIOTECHNOL PROGR JI Biotechnol. Prog. PD MAY-JUN PY 1997 VL 13 IS 3 BP 289 EP 295 DI 10.1021/bp970025a PG 7 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA XC684 UT WOS:A1997XC68400010 PM 9190079 ER PT J AU Stone, RP Johnson, SW AF Stone, RP Johnson, SW TI Survival, growth, and bioaccumulation of heavy metals by juvenile Tanner crabs (Chionoecetes bairdi) held on weathered mine tailings SO BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article RP Stone, RP (reprint author), NATL MARINE FISHERIES SERV,AUKE BAY LAB,ALASKA FISHERIES SCI CTR,NATL OCEAN & ATMOSPHER ADM,JUNEAU,AK 99801, USA. NR 13 TC 3 Z9 4 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0007-4861 J9 B ENVIRON CONTAM TOX JI Bull. Environ. Contam. Toxicol. PD MAY PY 1997 VL 58 IS 5 BP 830 EP 837 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA WQ347 UT WOS:A1997WQ34700023 PM 9115150 ER PT J AU Lamkin, J AF Lamkin, J TI Description of the larval stages of the Stromateoid fish Ariomma melanum, and its abundance and distribution in the Gulf of Mexico SO BULLETIN OF MARINE SCIENCE LA English DT Article AB The larval stages of Ariomma melanum are described from a series of specimens 2.0 mm to 24 mm SL. Specimens were collected primarily during annual spring ichthyoplankton surveys in the Gulf of Mexico from 1983 to 1987. A. melanum larvae may be identified as small as 2.0 mm based upon characters such as body shape, a bulbous occiput, and distinctive pigmentation patterns. Larvae were found primarily in the northeastern Gulf of Mexico. Adults are also concentrated in this area, occurring at bottom depths that ranged from 225 m to 480 m. Larvae were present at low levels throughout the year with peak abundance occurring in the spring and summer. Variation in abundance was also considerable between years. Larval A. melanum was most abundant in 1983, decreasing to a low in 1986, and was present in large numbers again in 1987. Substantial populations of A. melanum may exist along the deep shelf in the northeastern Gulf of Mexico. Sampling has been sporadic over the depth range of this species sc real abundance is not known. However, even if the stocks are considerable, the potential for commercial exploitation is questionable at this time. RP Lamkin, J (reprint author), NOAA, NMFS, SE FISHERIES SCI CTR, 75 VIRGINIA BEACH DR, MIAMI, FL 33149 USA. NR 11 TC 1 Z9 1 U1 1 U2 1 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 1997 VL 60 IS 3 BP 950 EP 959 PG 10 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA XT896 UT WOS:A1997XT89600016 ER PT J AU Richards, WJ AF Richards, WJ TI A new species of Leidotrigla (Pisces, Triglidae) from the Kermadec Islands of the South Pacific SO BULLETIN OF MARINE SCIENCE LA English DT Article AB A new species of Lepidotrigla from the Kermadec Islands in New Zealand waters is described. This species differs from Lepidotrigla brachyoptera Hutton, the other New Zealand Lepidotrigla, in having smaller scales (20 rows below the lateral line versus 10-11), more second dorsal and anal fin rays (D-2 Dorsal 16-18, mean 16.9 versus 15-17, mean 15.7 and Anal 16-18, mean 17.3 versus 16-18, mean 16.4), narrower interorbital width (5.3-6.0%SL, mean 5.6%SL versus 6.0-9.8%SL, mean 8.3%SL), and shorter gill rakers (1.3-1.7%SL, mean 1.5%SL versus 2.0-2.7%SL, mean 2.3%SL). The two species are allopatric but appear to be more closely related to each other than to other congeners L. brachyoptera is redescribed and compared with the new species. RP Richards, WJ (reprint author), NOAA,SE FISHERIES SCI CTR,75 VIRGINIA BEACH DR,MIAMI,FL 33149, USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 1997 VL 60 IS 3 BP 1050 EP 1059 PG 10 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA XT896 UT WOS:A1997XT89600026 ER PT J AU Sogard, SM AF Sogard, SM TI Size-selective mortality in the juvenile stage of teleost fishes: A review SO BULLETIN OF MARINE SCIENCE LA English DT Review ID COD GADUS-MORHUA; PERCH PERCA-FLAVESCENS; POLLOCK THERAGRA-CHALCOGRAMMA; SALMON ONCORHYNCHUS-KISUTCH; THE-YEAR BLUEFISH; EARLY-LIFE STAGES; ANCHOVY ENGRAULIS-MORDAX; YOUNG MIGRATORY TROUT; YELLOW PERCH; WALLEYE POLLOCK AB Individual variability in body size provides a template for selective mortality processes during early life history stages of teleost fishes. This size variability has generated the logically intuitive hypothesis that larger or faster growing members of a cohort gain a survival advantage over smaller conspecifics via enhanced resistance to starvation, decreased vulnerability to predators, and better tolerance of environmental extremes. This review evaluates field and laboratory studies that have examined size-based differences in survival, with emphasis on the juvenile stage of teleost fishes. The results in general support the ''bigger is better'' hypothesis, although a number of examples indicate non-selective mortality with no obvious size advantages. The reverse pattern, with enhanced survival of smaller individuals, is rare with the notable exception of bird predation. Major size-selective processes during the juvenile stage include overwinter mortality for temperate species, associated with either starvation or intolerance of physical extremes by smaller members of the young-of-the-year cohort, and predation, with smaller fish more susceptible to successful capture by predators. Most studies examining these processes have used indirect methods to evaluate size-selective mortality, with interpretation of results dependent on several critical assumptions. For methods that track size distributions over time, unbiased samples collected from the same population are critical, and changes in size distributions associated with mortality must be distinguished from changes due to individual growth. The latter requirement can be met with the direct, ''characteristics of survivors'' method, but few studies have used this approach. Experimental methods isolating specific mechanisms of size-specific mortality must appropriately represent the natural context of environmental factors. Specific predator/prey combinations, for example, can elucidate size-based prey preferences bur may be irrelevant compared to the natural, multi-species predator field. The composition of the predator field and its correspondence to size-spectrum theory is crucial to the probability of size-selective predation as a cohort progresses through the juvenile stage. Distinction of selection on body size vs. selection on growth rate has received little attention. However, a number of physiological constraints and ecological trade-offs can place restrictions on growth rates and apparently override the advantages of large body size. Identifying the major sources of mortality and how they operate in the juvenile stage has valuable applications in understanding population dynamics and recruitment variability. RP Sogard, SM (reprint author), HATFIELD MARINE SCI CTR, NATL MARINE FISHERIES SERV, ALASKA FISHERIES SCI CTR, NEWPORT, OR 97365 USA. RI Wright, Dawn/A-4518-2011 OI Wright, Dawn/0000-0002-2997-7611 NR 144 TC 703 Z9 711 U1 7 U2 148 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 1997 VL 60 IS 3 BP 1129 EP 1157 PG 29 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA XT896 UT WOS:A1997XT89600029 ER PT J AU Pielke, RA Kimple, J Adams, C Baker, J Changnon, S Heideman, KF Leavitt, P Keener, RN McCarthy, J Miller, K Murphy, AH Pulwarty, RS Roth, R Stanley, EM Stewart, T Zacharias, T AF Pielke, RA Kimple, J Adams, C Baker, J Changnon, S Heideman, KF Leavitt, P Keener, RN McCarthy, J Miller, K Murphy, AH Pulwarty, RS Roth, R Stanley, EM Stewart, T Zacharias, T TI Societal aspects of weather: Report of the Sixth Prospectus Development Team of US Weather Research Program to NOAA and NSF SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material AB U.S. Weather Research Program (USWRP) Prospectus Development Teams (PDTs) are small groups of advisors that are convened by the program's lead scientist on a one-time basis to discuss critical issues and to provide advice related to future directions of the program. PDTs are a principal source of information for the Science Advisory Committee, which is standing committee charged with the duty of making recommendations to the program office based upon overall program objectives. It is generally accepted that weather problems are both social and physical phenomena. Research findings from the social sciences have been crucially important in understanding and improving human responses to economic, social, and environmental weather-related risks. Despite the centrality of this research area, it has in the past received too little attention and too few resources. PDT 6 brought together a broad range of expertise and experience to focus on three main objectives: 1) to discuss and assess the nature and scope of U.S. weather problems, 2) to conduct a brief review of the societal aspects of weather, and 3) to discuss and explore the role of existing and improved weather information in addressing those problems. Several themes emerged in discussion at the workshop. First and foremost, users need to be included in all aspects of the USWRP and not just at the ''end of the line.'' Research in social aspects of weather can help to facilitate constructive interactions between physical scientists and users. Second, societal aspects research can help to focus on issues related to pressing national weather problems. The complex nature of these problems is poorly understood. Problem-oriented social science research can help to identify the factors that characterize the problems and to define the potential and actual value of various research and research-related products. C1 UNIV OKLAHOMA,NORMAN,OK 73019. NATL WEATHER SERV,WASHINGTON,DC. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. ILLINOIS STATE WATER SURVEY,CHAMPAIGN,IL 61820. PHILLIPS LAB,HANSCOM AFB,MA. WEATHER SERV CORP,LEXINGTON,MA. DUKE POWER CO,CHARLOTTE,NC. PREDICT & EVALUAT SYST,CORVALLIS,OR. UNIV COLORADO,BOULDER,CO 80309. CNA INSURANCE,NORTHBROOK,IL. FULTON CTY EMERGENCY MANAGEMENT AGCY,ATLANTA,GA. SUNY ALBANY,ALBANY,NY 12222. NATL CROP INSURANCE PROGRAM,OVERLAND PK,KS. RP Pielke, RA (reprint author), NATL CTR ATMOSPHER RES,ENVIRONM & SOC IMPACTS GRP,POB 3000,BOULDER,CO 80303, USA. NR 16 TC 11 Z9 11 U1 3 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1997 VL 78 IS 5 BP 867 EP 876 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XD572 UT WOS:A1997XD57200010 ER PT J AU Smith, R Paegle, J Clark, T Cotton, W Durran, D Forbes, G Marwitz, J Mass, C McGinley, J Pan, HL Ralph, M AF Smith, R Paegle, J Clark, T Cotton, W Durran, D Forbes, G Marwitz, J Mass, C McGinley, J Pan, HL Ralph, M TI Local and remote effects of mountains on weather: Research needs and opportunities SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material ID MESOSCALE CONVECTIVE SYSTEM; ELEVATED MIXED-LAYER; GRAVITY-WAVE DRAG; LOW-LEVEL JET; UNITED-STATES; GREAT-PLAINS; AIR-FLOW; GENERAL-CIRCULATION; DIURNAL-VARIATIONS; DATA ASSIMILATION C1 UNIV UTAH,SALT LAKE CITY,UT. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. COLORADO STATE UNIV,FT COLLINS,CO 80523. UNIV WASHINGTON,SEATTLE,WA 98195. PENN STATE UNIV,UNIVERSITY PK,PA 16802. UNIV WYOMING,LARAMIE,WY 82071. NATL OCEAN & ATMOSPHER ADM,WASHINGTON,DC. NATL WEATHER SERV,WASHINGTON,DC. RP Smith, R (reprint author), YALE UNIV,DEPT GEOL & GEOPHYS,BOX 208109,NEW HAVEN,CT 06520, USA. RI Durran, Dale/G-3677-2015 OI Durran, Dale/0000-0002-6390-2584 NR 98 TC 42 Z9 42 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1997 VL 78 IS 5 BP 877 EP 892 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XD572 UT WOS:A1997XD57200011 ER PT J AU Schmetz, J Roesli, HP Menzel, WP AF Schmetz, J Roesli, HP Menzel, WP TI Third International Winds Workshop SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material AB The Third International Winds Workshop was held in Ascona, Switzerland. from 10 to 12 June 1996. The workshop was organized by the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), which represents the national weather services of 17 European countries. The Swiss Meteorological Service was the local host. This third winds workshop followed previous meetings in Washington, D.C., in September 1991 and in Tokyo, Japan, in December 1993. The winds workshops have been organized to broaden and formalize the cooperation among users and producers as understanding of the characteristics of satellite-tracked winds increased and their use in numerical weather prediction centers advanced. This report describes the organization of International Winds Workshops as part of the activities of the Coordination Group for Meteorological Satellites and provides an executive summary of, and the recommendations from, the Third International Winds Workshop. C1 SWISS METEOROL INST,LOCARNO,SWITZERLAND. NOAA,NESDIS,MADISON,WI. RP Schmetz, J (reprint author), EUMETSAT,AM KAVALLERIESAND 31,D-64295 DARMSTADT,GERMANY. RI Menzel, W. Paul/B-8306-2011 OI Menzel, W. Paul/0000-0001-5690-1201 NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1997 VL 78 IS 5 BP 893 EP 896 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XD572 UT WOS:A1997XD57200012 ER PT J AU Wagenmaker, D AF Wagenmaker, D TI Fifth Annual US/Canada Workshop on Great Lakes Operational Meteorology SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material RP Wagenmaker, D (reprint author), NOAA,NATL WEATHER SERV,FORECAST OFF,DETROIT,MI, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1997 VL 78 IS 5 BP 970 EP 970 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XD572 UT WOS:A1997XD57200017 ER PT J AU Halpert, MS Bell, GD AF Halpert, MS Bell, GD TI Climate assessment for 1996 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID OUTGOING LONGWAVE RADIATION; SEA-SURFACE TEMPERATURE; 40-50 DAY OSCILLATION; SOUTHERN OSCILLATION; NORTHERN-HEMISPHERE; WINTER TEMPERATURES; EL-NINO; CIRCULATION; PRECIPITATION; CONVECTION AB The climate of 1996 can be characterized by several phenomena that reflect substantial deviations from the mean state of the atmosphere persisting from months to seasons. First, mature cold-episode conditions persisted across the tropical Pacific from November 1995 through May 1996 and contributed to large-scale anomalies of atmospheric circulation, temperature, and precipitation across the Tropics, the North Pacific and North America. These anomalies were in many respects opposite to those that had prevailed during the past several years in association with a prolonged period of tropical Pacific warm-episode conditions (ENSO). Second, strong tropical intraseasonal (Madden-Julian oscillations) activity was observed during most of the year. The impact of these oscillations on extratropical circulation variability was most evident late in the year in association with strong variations in the eastward extent of the East Asian jet and in the attendant downstream circulation, temperature, and precipitation patterns over the eastern North Pacific and central North America. Third, a return to the strong negative phase of the atmospheric North Atlantic oscillation (NAG) during November 1995-February 1996, following a nearly continuous 15-yr period of positive-phase NAO conditions, played a critical role in affecting temperature and precipitation patterns across the North Atlantic, Eurasia, and northern Africa. The NAO also contributed to a significant decrease in wintertime temperatures across large portions of Siberia and northern Russia from those that had prevailed during much of the 1980s and early 1990s. Other regional aspects of the short-term climate during 1996 included severe drought across the southwestern United States and southern plains states during October 1995-May 1996, flooding in the Pacific Northwest region of the United States during the 1995/96 and 1996/97 winters, a cold and extremely snowy 1995/96 winter in the eastern United States, a second consecutive year of above-normal North Atlantic hurricane activity, near-normal rains in the African Sahel, above-normal rainfall across southeastern Africa during October 1995-April 1996, above-normal precipitation for most of the year across eastern and southeastern Australia following severe drought in these areas during 1995, and generally near-normal monsoonal rains in India with significantly below-normal rainfall in Bangladesh and western Burma. The global annual mean surface temperature for land and marine areas during 1996 averaged 0.21 degrees C above the 1961-90 base period means. This is a decrease of 0.19 degrees C from the record warm year of 1995 but was still among the 10 highest values observed since 1860. The global land-only temperature for 1996 was 0.06 degrees C above normal and was the lowest anomaly observed since 1985 (-0.11 degrees C). Much of this relative decrease in global temperatures occurred in the Northern Hemisphere extratropics, where land-only temperatures dropped from 0.42 degrees C above normal in 1995 to 0.04 degrees C below normal in 1996. The year also witnessed a continuation of near-record low atone amounts in the Southern Hemisphere stratosphere, along with an abnormally prolonged appearance of the ''ozone hole'' into early December. The areal extent of the ozone hole in November and early December exceeded that previously observed for any such period on record. However, its areal extent at peak amplitude during late September-early October was near that observed during the past several years. C1 NOAA,CLIMATE PREDICT CTR,NCEP,NWS,WASHINGTON,DC. RP Halpert, MS (reprint author), NOAA,NCEP,CLIMATE PREDICT CTR,W-NP52,NSC,RM 605,5200 AUTH RD,CAMP SPRINGS,MD 20746, USA. NR 43 TC 31 Z9 31 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1997 VL 78 IS 5 BP S1 EP S49 PG 49 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA XD572 UT WOS:A1997XD57200018 ER PT J AU Merrick, RL Loughlin, TR AF Merrick, RL Loughlin, TR TI Foraging behavior of adult female and young-of-the-year Steller sea lions in Alaskan waters SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID ANTARCTIC FUR SEALS; HOME-RANGE; EUMETOPIAS-JUBATUS; NORTHERN; ABUNDANCE; MAMMALS AB One explanation for recent declines in the Alaskan Steller sea lion (Eumetopias jubatus) population is that the availability of preferred prey has changed. Part of our evaluation of this hypothesis involved the use of conventional radio and satellite-linked time-depth recorder transmitters to compare summer and winter foraging of adult female and young-of-the-year Steller sea lions in Alaska waters. Foraging effort was not significantly different seasonally for postpartum adult females, though females with dependent young in winter may increase their foraging effort. In winter, all adult females made longer trips over larger home ranges and dove deeper. Young sea lions exerted less foraging effort, had the shallowest and briefest dives, and had home ranges intermediate in size to the two groups of adult females. Their foraging ability appears to develop throughout the first year. We conclude that adult female sea lions can exploit prey throughout the Gulf of Alaska and Bering Sea, and are constrained only by their reproductive status and seasonal changes in prey availability. Young sea lions' diving is more limited because their physiological and behavioral development constrains them from diving like an adult. Perhaps most important, dives remain shallow through the first year. Consequently, young sea lions could be more easily food-limited by changes in prey distribution. RP Merrick, RL (reprint author), NOAA,NATL MARINE FISHERIES SERV,NATL MARINE MAMMAL LAB,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115, USA. NR 60 TC 144 Z9 149 U1 1 U2 13 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD MAY PY 1997 VL 75 IS 5 BP 776 EP 786 DI 10.1139/z97-099 PG 11 WC Zoology SC Zoology GA XB778 UT WOS:A1997XB77800014 ER PT J AU Takagi, S Chow, LC Shih, S Sieck, BA AF Takagi, S Chow, LC Shih, S Sieck, BA TI Effect of a two-solution fluoride mouth rinse on deposition of loosely bound fluoride on sound root tissue and remineralization of root lesions in vitro SO CARIES RESEARCH LA English DT Article DE calcium fluoride; fluoride uptake; pH-cycling model; root remineralization; sodium hexafluorosilicate; two-solution fluoride rinse ID SURFACE CARIES; TOOTH ENAMEL; INVITRO; DEMINERALIZATION; INVIVO AB A constant-composition fluoride (F) titration method was used to measure the amount of leachable F deposited on root surfaces in vitro by a 1-min rinse with a 12 mmol/l sodium fluoride (228 mu g/g F) solution or a two-solution rinse that contained 2 mmol/l sodium fluorosilicate (228 mu g/g total F) and 10 mmol/l calcium chloride. The mean +/- standard deviations (n = 3) F uptake from the two rinse treatments were 0.70+/-0.24 mu g/cm(2) and 3.25+/-0.74 mu g/cm(2), respectively. In a separate experiment, the effects of sodium fluoride and the two-solution rinses on remineralization of root lesions were evaluated in an in vitro pH cycling model. The results showed that the average decrease in mineral loss (Delta Z) in the two-solution rinse group (60%) was significantly greater than that obtained in the NaF rinse (41%) or the control (9%) group. RP Takagi, S (reprint author), NATL INST STAND & TECHNOL,AMER DENT ASSOC HLTH FDN,PAFFENBARGER RES CTR,GAITHERSBURG,MD 20899, USA. FU NIDCR NIH HHS [DEO5354] NR 18 TC 9 Z9 9 U1 0 U2 1 PU KARGER PI BASEL PA ALLSCHWILERSTRASSE 10, CH-4009 BASEL, SWITZERLAND SN 0008-6568 J9 CARIES RES JI Caries Res. PD MAY-JUN PY 1997 VL 31 IS 3 BP 206 EP 211 PG 6 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA WY178 UT WOS:A1997WY17800009 PM 9165192 ER PT J AU Martys, NS Ferraris, CF AF Martys, NS Ferraris, CF TI Capillary transport in mortars and concrete SO CEMENT AND CONCRETE RESEARCH LA English DT Article ID PERMEABILITY AB Results are presented of a study concerning capillary transport of water in concretes and mortars as a function of water/cement ratio, sand size distribution, and curing. Our studies indicate that the capillary sorption (1) of water in concrete exhibits a complex time dependence. At early times, of the order of one hour, the total water uptake increased with the t(1/2) behavior of typical capillary sorption theories. At longer times, of the order of tens of days, a slow crossover regime is seen as the rate of capillary suction decreases. At very long times, of order hundreds of days, a slower uptake which may be driven by the capillary forces in the smaller gel pores is found. Again the t(1/2) behavior is recovered but with a much smaller sorptivity coefficient. We describe an empirical fitting form for data which describes capillary suction at both short and long times. Aspects of the experimental design including sample drying and exposure to air are discussed. The utility of service life predictions from such measurements is discussed. (C) 1997 Elsevier Science Ltd. RP Martys, NS (reprint author), NIST,BLDG MAT DIV,GAITHERSBURG,MD 20899, USA. NR 22 TC 148 Z9 161 U1 4 U2 29 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0008-8846 J9 CEMENT CONCRETE RES JI Cem. Concr. Res. PD MAY PY 1997 VL 27 IS 5 BP 747 EP 760 DI 10.1016/S0008-8846(97)00052-5 PG 14 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA XE839 UT WOS:A1997XE83900012 ER PT J AU Currie, LA AF Currie, LA TI Detection: International update, and some emerging di-lemmas involving calibration, the blank, and multiple detection decisions SO CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS LA English DT Article; Proceedings Paper CT 3rd International Conference on Environmetrics and Chemometrics CY SEP 11-13, 1995 CL LAS VEGAS, NV SP US EPA, NISS, NIST, Elsevier Sci Publ, Gulf Coast Hazardous Subst Res Ctr, Monsanto Chem Co, Texas A&M Univ DE international standards; IUPAC; ISO; detection limits; quantification limits; hypothesis testing; chemical measurement process; performance characteristics; calibration; multiple detection decisions; multivariate detection limits ID DETECTION LIMITS; NOMENCLATURE; CURVES AB Detection and quantification capabilities represent fundamental performance characteristics of measurement processes, yet there have been decades of confusion and miscommunication regarding the underlying concepts and terminology. New, co-ordinated documents prepared by the International organization for standardization (ISO) [1] and the International union of pure and applied chemistry (IUPAC) [2] promise to alleviate this situation by providing, for the first time, a harmonized position of standards and recommendations for adoption by the international scientific community. The first section of this paper contains a brief introduction to the events leading to the ISO and IUPAC efforts. Section 2 consists of (1) a brief review of the history of 'detection limits' in chemistry, illustrating the critical need for the development of a sound and uniform system of terms and symbols; and (2) a review of the ISO-IUPAC deliberations and the ensuing harmonized position on concepts and nomenclature. Section 3 treats fundamental applications of the underlying concepts, together with a series of unresolved or 'open' questions involving: detection and quantification capabilities in the signal and concentration domains, respectively; and the link between calibration and detection and quantification limits, together with the blank-intercept dichotomy. Also included are special treatments and approximations, developed in part for the IUPAC document, involving the non-central-t, and the exact (non-normal) distribution of the estimated concentration. The final section (Section 4) introduces issues and approaches to multiple independent and multivariate detection decisions and limits, and concludes with a glimpse at some challenges involving the multivariate blank and non-monotonic calibration functions. RP Currie, LA (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 60 TC 105 Z9 107 U1 1 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7439 J9 CHEMOMETR INTELL LAB JI Chemometrics Intell. Lab. Syst. PD MAY PY 1997 VL 37 IS 1 BP 151 EP 181 DI 10.1016/S0169-7439(97)00009-9 PG 31 WC Automation & Control Systems; Chemistry, Analytical; Computer Science, Artificial Intelligence; Instruments & Instrumentation; Mathematics, Interdisciplinary Applications; Statistics & Probability SC Automation & Control Systems; Chemistry; Computer Science; Instruments & Instrumentation; Mathematics GA XB913 UT WOS:A1997XB91300017 ER PT J AU Becker, PR Wise, SA Thorsteinson, L Koster, BJ Rowles, T AF Becker, PR Wise, SA Thorsteinson, L Koster, BJ Rowles, T TI Specimen banking of marine organisms in the United States: Current status and long-term prospective SO CHEMOSPHERE LA English DT Article; Proceedings Paper CT 2nd International Symposium & Workshop on Biological Environmental Specimen Banking (BESB-2) CY MAY 20-23, 1996 CL SWEDISH MUSEUM NAT HIST, STOCKHOLM, SWEDEN HO SWEDISH MUSEUM NAT HIST ID ORGANOCHLORINE CONTAMINANTS; FOOD-CHAINS; FISH AB A major part of the activities conducted over the last decade by the National Biomonitoring Specimen Bank (NBSB) has involved the archival of marine specimens collected by ongoing environmental monitoring programs. These archived specimens include bivalves, marine sediments, and fish tissues collected by the National status and Trends and the Exxon Valdez Oil Spill Damage Assessment programs, and marine mammal tissues collected by the Marine Mammal Health and Stranding Response Program and the Alaska Marine Mammal Tissue Archival Project. In addition to supporting these programs, the specimens have been used to investigate circumpolar patterns of chlorinated hydrocarbon concentrations, genetic separation of marine animal stocks, baseline levels of essential and nonessential elements in marine mammals, and the potential risk to human consumers in the Arctic from anthropogenic contaminants found in local subsistence foods. The NBSB specimens represent a resource that has the potential for addressing future issues of marine environmental quality and ecosystem changes through retrospective analysis; however, an ecosystem-based food web approach would maximize this potential. The current status of the NBSB activities related to the banking of marine organisms is presented and discussed, the long-term prospective of these activities is presented, and the importance of an ecosystem-based food web monitoring approach to the value of specimen banking is discussed. C1 NIST, GAITHERSBURG, MD 20899 USA. US GEOL SURVEY, BIOL RESOURCES DIV, SEATTLE, WA USA. NOAA, OFF PROTECTED RESOURCES, SILVER SPRING, MD USA. RP Becker, PR (reprint author), NATL INST STAND & TECHNOL, CHARLESTON, SC USA. NR 33 TC 10 Z9 10 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-6535 EI 1879-1298 J9 CHEMOSPHERE JI Chemosphere PD MAY PY 1997 VL 34 IS 9-10 BP 1889 EP 1906 DI 10.1016/S0045-6535(97)00051-9 PG 18 WC Environmental Sciences SC Environmental Sciences & Ecology GA WY925 UT WOS:A1997WY92500004 PM 9159892 ER PT J AU Anulacion, BF Bill, BD Collier, TK AF Anulacion, BF Bill, BD Collier, TK TI Stability of cytochrome P4501A-associated enzyme activity in cryogenically stored teleost liver samples SO CHEMOSPHERE LA English DT Article; Proceedings Paper CT 2nd International Symposium & Workshop on Biological Environmental Specimen Banking (BESB-2) CY MAY 20-23, 1996 CL SWEDISH MUSEUM NAT HIST, STOCKHOLM, SWEDEN HO SWEDISH MUSEUM NAT HIST ID IMMUNOHISTOCHEMICAL LOCALIZATION; EXTRAHEPATIC TISSUES; VETULUS AB Induction of cytochrome P4501A (CYP1A), more specifically the associated enzyme activity aryl hydrocarbon hydroxylase (AHH), has been shown to be one of the most sensitive measures of exposure of vertebrate animals to a range of organic chemical contaminants. However, in order to reliably use this biochemical method for analyzing archived samples, the stability of the enzyme activity in storage must be ascertained. Stability of AHH activity was determined for both tissue sections and subcellular fractions of liver collected from English sole (Pleuronectes vetulus), and held in cryogenic storage for up to 24 months. Our overall recommendations for sample collection, handling, storage, and assay are given. RP Anulacion, BF (reprint author), NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,ENVIRONM CONSERVAT DIV,2725 MONTLAKE BLVD E,SEATTLE,WA 98112, USA. NR 18 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-6535 J9 CHEMOSPHERE JI Chemosphere PD MAY PY 1997 VL 34 IS 9-10 BP 2029 EP 2039 DI 10.1016/S0045-6535(97)00065-9 PG 11 WC Environmental Sciences SC Environmental Sciences & Ecology GA WY925 UT WOS:A1997WY92500018 PM 9159902 ER PT J AU Becker, PR Mackey, EA Demiralp, R Schantz, MM Koster, BJ Wise, SA AF Becker, PR Mackey, EA Demiralp, R Schantz, MM Koster, BJ Wise, SA TI Concentrations of chlorinated hydrocarbons and trace elements in marine mammal tissues archived in the US National Biomonitoring Specimen Bank SO CHEMOSPHERE LA English DT Article; Proceedings Paper CT 2nd International Symposium & Workshop on Biological Environmental Specimen Banking (BESB-2) CY MAY 20-23, 1996 CL SWEDISH MUSEUM NAT HIST, STOCKHOLM, SWEDEN HO SWEDISH MUSEUM NAT HIST ID ORGANOCHLORINE CONTAMINANTS; FOOD-CHAINS; PROGRAM; CANADA AB The U.S. National Biomonitoring Specimen Bank (NBSB) provides for the Long term storage of well documented and preserved specimens representing several types of environmental matrices. A major part of this inventory consists of marine mammal tissues (e.g., blubber, liver, kidney, and muscle). Within the NBSB selected specimens are periodically analyzed for chlorinated hydrocarbons and trace elements. Although only 20% of the 560 marine mammal specimens in the NBSB have been analyzed, the database is of value in evaluating the stability of analytes and sample degradation during storage, for comparing with results from samples collected in the future for long-term monitoring, and for comparing with analytical results from other laboratories on samples collected at the same time for monitoring purposes. The NBSB analytical database contains results for 37 elements, many of which are not analyzed routinely by conventional analytical techniques used in monitoring programs, and the following organic compounds: selected PCB congeners, DDT compounds, alpha- and gamma-HCH, HCB, heptachlor epoxide, oxychlordane, cis-chlordane, trans-chlordane, cis-nonachlor, trans-nonachlor, and dieldrin in 9 marine mammal species: northern fur seal (Callorhinus ursinus), ringed seal (Phoca hispida), spotted seal (P. largha), bearded seal (Erignathus barbatus), pilot whale (Globicephala melas), harbor porpoise (Phocoena phocoena), white-sided dolphin (Lagenorhynchus acutus), beluga whale (Delphinapterus leucas), and bowhead whale (Balaena mysticetus). Analyses of beluga whale blubber for toxaphene and additional chlorinated hydrocarbons are obtained through collaboration with the Department of Fisheries and Oceans Canada. C1 NIST, GAITHERSBURG, MD 20899 USA. RP Becker, PR (reprint author), NATL INST STAND & TECHNOL, CHARLESTON, SC USA. NR 38 TC 42 Z9 46 U1 2 U2 16 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-6535 EI 1879-1298 J9 CHEMOSPHERE JI Chemosphere PD MAY PY 1997 VL 34 IS 9-10 BP 2067 EP 2098 DI 10.1016/S0045-6535(97)00069-6 PG 32 WC Environmental Sciences SC Environmental Sciences & Ecology GA WY925 UT WOS:A1997WY92500022 PM 9159906 ER PT J AU Krahn, MM Becker, PR Tilbury, KL Stein, JE AF Krahn, MM Becker, PR Tilbury, KL Stein, JE TI Organochlorine contaminants in blubber of four seal species: Integrating biomonitoring and specimen banking SO CHEMOSPHERE LA English DT Article; Proceedings Paper CT 2nd International Symposium & Workshop on Biological Environmental Specimen Banking (BESB-2) CY MAY 20-23, 1996 CL SWEDISH MUSEUM NAT HIST, STOCKHOLM, SWEDEN HO SWEDISH MUSEUM NAT HIST ID POLYCHLORINATED-BIPHENYLS; PHOCA-HISPIDA; COMMON SEALS; PCBS; RESIDUES; PESTICIDES; MAMMALS; EASTERN; WATERS; TISSUE AB Blubber samples from four Alaska seal species (bearded seal, Erignathus barbatus; harbor seal, Phoca vitulina; northern fur seal, Callorhinus ursinus; ringed seat, P. hispida) were collected for inclusion in the US National Biomonitoring Specimen Bank, as well as for immediate analysis as part of the contaminant monitoring component of the US National Marine Fisheries Service's Marine Mammal Health and Stranding Response Program. The blubber samples were analyzed for organochlorine (OC) contaminants (e.g., PCB congeners, pesticides, DDTs). Results for bearded and ringed seals from the Alaska Arctic revealed low blubber concentrations of OC contaminants. Harbor seals from Prince William Sound, Gulf of Alaska, had somewhat higher blubber concentrations of OC contaminants. In contrast, northern fur seals sampled from the Pribilof Islands had blubber concentrations of certain OC contaminants that were about an order of magnitude higher than those found in the other seal species. Differences in contaminant concentrations among the Alaska seals may be explained by differences in feeding habits and migratory patterns; age or gender did not appear to account for the differences observed. The highest concentrations of OCs were found in harbor seals stranded along the northwestern US mainland, which is consistent with higher concentrations of anthropogenic contaminants being found in urban coastal areas than in more remote Arctic environments. The integration of real-time contaminant monitoring with specimen banking provides important baseline data that can be used to plan and manage banking activities. This includes identifying appropriate specimens that are useful in assessing temporal trends and increasing the utility of the banked samples in assessing chemical contaminant accumulation and relationships to biological effects. C1 NATL INST STAND & TECHNOL, CHARLESTON LAB, CHARLESTON, SC 29412 USA. RP Krahn, MM (reprint author), NOAA, NATL MARINE FISHERIES SERV, NW FISHERIES CTR, ENVIRONM CONSERVAT DIV, 2725 MONTLAKE BLVD E, SEATTLE, WA 98112 USA. NR 30 TC 40 Z9 41 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-6535 EI 1879-1298 J9 CHEMOSPHERE JI Chemosphere PD MAY PY 1997 VL 34 IS 9-10 BP 2109 EP 2121 DI 10.1016/S0045-6535(97)00071-4 PG 13 WC Environmental Sciences SC Environmental Sciences & Ecology GA WY925 UT WOS:A1997WY92500024 PM 9159908 ER PT J AU Tilbury, KL Stein, JE Meador, JP Krone, CA Chan, SL AF Tilbury, KL Stein, JE Meador, JP Krone, CA Chan, SL TI Chemical contaminants in harbor porpoise (Phocoena phocoena) from the north Atlantic coast: Tissue concentrations and intra- and inter-organ distribution SO CHEMOSPHERE LA English DT Article; Proceedings Paper CT 2nd International Symposium & Workshop on Biological Environmental Specimen Banking (BESB-2) CY MAY 20-23, 1996 CL SWEDISH MUSEUM NAT HIST, STOCKHOLM, SWEDEN HO SWEDISH MUSEUM NAT HIST ID POLYCHLORINATED-BIPHENYLS PCBS; CETACEANS; METALS AB Concentrations of chlorinated hydrocarbons (CHs), such as polychlorinated biphenyls (PCBs), were measured in subsamples taken from different anatomical locations of blubber and liver of three apparently healthy harbor porpoises (Phocoena phocoena) incidentally caught in a gill-net fishery along the northwest Atlantic coast; selected elements (e.g., mercury) were measured in subsamples of liver. The vertical distribution (skin to muscle) of contaminants within blubber was also determined. Additionally, the concentrations of CHs and elements were determined in individual samples of brain, lung, kidney, and testis to assess how the disposition of toxic chemicals may be dependent on the physiological characteristics of a specific organ. Statistical analyses of the results showed that the anatomical location of the blubber or liver sample had no significant effect on concentrations of either CHs in blubber and liver, or of selected elements in liver. However, there were statistical differences between strata of blubber (skin to muscle) for the concentrations of CHs. As expected, the results showed that the CH concentrations, based on wet weight, were considerably higher in the blubber than in the other tissues; however, the concentrations of CHs in the different tissues were more comparable when values were based on total lipid weight with the exception of the brain where lipid normalized concentrations were lower than in all other tissues. This low relative accumulation of lipophilic contaminants in the brain tissue may be due to the presence of the blood-brain barrier, or due to a lower proportion of neutral lipids, such as triglycerides, as analysis for percent lipid and for the proportion of specific lipid classes showed. RP Tilbury, KL (reprint author), NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES CTR,DIV ENVIRONM CONSERVAT,2725 MONTLAKE BLVD E,SEATTLE,WA 98112, USA. NR 29 TC 42 Z9 42 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-6535 J9 CHEMOSPHERE JI Chemosphere PD MAY PY 1997 VL 34 IS 9-10 BP 2159 EP 2181 DI 10.1016/S0045-6535(97)00076-3 PG 23 WC Environmental Sciences SC Environmental Sciences & Ecology GA WY925 UT WOS:A1997WY92500029 PM 9159912 ER PT J AU Moss, SC Robertson, JL Neumann, DA Reinhard, L AF Moss, SC Robertson, JL Neumann, DA Reinhard, L TI Anomalous static displacements and their relation to lattice dynamics in Fe0.53Cr0.47 SO COMPUTATIONAL MATERIALS SCIENCE LA English DT Article; Proceedings Paper CT Joint NFS/CNRS Workshop on Alloy Theory CY OCT 11-15, 1996 CL STRASBOURG, FRANCE SP NFS, CNRS AB Summarizing our prior work on X-ray and neutron scattering, we discuss the demands that careful data collection place on the interpretation and understanding of atomic size and atomic displacements in binary alloys, In the present case, when the size difference between pure Fe and pure Cr in their bcc states is only 0.6%, atom size disparities nonetheless place stringent demands on the basic physics of these solid solutions and lead to effects that resemble premonitory fluctuations above the first order phase transition to the Frank-Kasper sigma-phase characterized both by (111) planar collapse and by ordered icosahedral units. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. NIST,GAITHERSBURG,MD 20899. ETH ZENTRUM,CH-8092 ZURICH,SWITZERLAND. RP Moss, SC (reprint author), UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204, USA. NR 12 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0256 J9 COMP MATER SCI JI Comput. Mater. Sci. PD MAY PY 1997 VL 8 IS 1-2 BP 33 EP 38 DI 10.1016/S0927-0256(97)00013-X PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA XE910 UT WOS:A1997XE91000006 ER PT J AU McCormack, R Asta, M Hoyt, JJ Chakoumakos, BC Misture, ST Althoff, JD Johnson, DD AF McCormack, R Asta, M Hoyt, JJ Chakoumakos, BC Misture, ST Althoff, JD Johnson, DD TI Experimental and theoretical investigations of order-disorder in Cu2AlMn SO COMPUTATIONAL MATERIALS SCIENCE LA English DT Article; Proceedings Paper CT Joint NFS/CNRS Workshop on Alloy Theory CY OCT 11-15, 1996 CL STRASBOURG, FRANCE SP NFS, CNRS ID METALLIC ALLOYS; TRANSITIONS; SYSTEM; CU; NI AB A combination of X-ray and neutron powder diffract:on has been used to measure the two long range order parameters vs. temperature below the disorder-B2 transition in the ternary alloy Cu2AlMn. The results indicate that at temperatures just below the critical point the Al + Mn sublattice is enriched in Al. First-principles calculations based on only the atomic numbers of Cu, Mn and Al support the experimentally-observed preference of Al for the Al + Mn sublattice, and reveal the interplay between the constituent binary systems that gives rise to this behavior. C1 SANDIA NATL LABS, COMPUTAT MAT SCI DEPT, LIVERMORE, CA 94551 USA. WASHINGTON STATE UNIV, SCH MECH & MAT ENGN, PULLMAN, WA 99164 USA. OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. OAK RIDGE NATL LAB, HIGH TEMP MAT LAB, OAK RIDGE, TN 37831 USA. RP McCormack, R (reprint author), NIST, MAT SCI & ENGN LAB, GAITHERSBURG, MD 20899 USA. RI Chakoumakos, Bryan/A-5601-2016; OI Chakoumakos, Bryan/0000-0002-7870-6543; Johnson, Duane/0000-0003-0794-7283 NR 21 TC 6 Z9 6 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0256 J9 COMP MATER SCI JI Comput. Mater. Sci. PD MAY PY 1997 VL 8 IS 1-2 BP 39 EP 45 DI 10.1016/S0927-0256(97)00014-1 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA XE910 UT WOS:A1997XE91000007 ER PT J AU McCormack, R Burton, BP AF McCormack, R Burton, BP TI Modeling phase stability in A(B1/3B'(2/3))O-3 perovskites SO COMPUTATIONAL MATERIALS SCIENCE LA English DT Article; Proceedings Paper CT Joint NFS/CNRS Workshop on Alloy Theory CY OCT 11-15, 1996 CL STRASBOURG, FRANCE SP NFS, CNRS ID EFFECTIVE CLUSTER INTERACTIONS; TOTAL-ENERGY CALCULATIONS; ALLOYS AB Order-disorder phenomena on the simple-cubic B-site sublattice in A(B1/3B'(2/3))O-3 perovskites is examined. A simple cubic groundstate analysis in the cube approximation reveals that this approximation is inadequate for A(B1/3B'(2/3))O-3 perovskites, because it cannot predict a common experimentally-observed [111] superstructure. A partial vertex enumeration technique is used to demonstrate that a cube + linear triplet approximation is sufficient. First-principles calculations were performed for Ba(Zn1/3Ta2/3)O-3 (BZT) and Pb(Mg1/3Nb2/3)O-3 (PMN), two technologically interesting materials, in an effort to construct generalized Ising model Hamiltonians to enable simulations of these materials. Both ionic model (SSCAD) and pseudopotential (PP) calculations were done, enumerating the relative energies of a series of B-site superstructures. Structural hierarchies are reasonable and predict the [111] groundstate for both BZT and PMN, despite the fact that it is not observed in the latter. The pseudopotential results also indicate the possibility of metal-insulator transitions in BZT as a function of B-site configuration. The latter result indicates a possible explanation for the curious dielectric properties of non-isovalent mixed B-site materials. Differences were found between the SSCAD and PP calculations for BZT; these indicate the SSCAD calculations are probably sufficient for low-energy excitations, but inaccurate for high-energy structures. RP McCormack, R (reprint author), NIST,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899, USA. NR 24 TC 12 Z9 12 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0256 J9 COMP MATER SCI JI Comput. Mater. Sci. PD MAY PY 1997 VL 8 IS 1-2 BP 153 EP 160 DI 10.1016/S0927-0256(97)00028-1 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA XE910 UT WOS:A1997XE91000021 ER PT J AU Bisagni, JJ OReilly, JE Barnard, AH Wolfteich, CM AF Bisagni, JJ OReilly, JE Barnard, AH Wolfteich, CM TI Determination of optimum aerosol optical thickness ratios for atmospheric correction of coastal zone color scanner data in the Georges Bank Gulf of Maine Region SO CONTINENTAL SHELF RESEARCH LA English DT Article ID NEAP TIDAL CYCLE; ATLANTIC BIGHT; PIGMENT CONCENTRATIONS; VARIABILITY; ESTUARY; IMAGERY; OCEAN AB The influence of varying aerosol optical thickness ratios (AOTR) on the precision and accuracy of satellite-derived CZCS pigment was evaluated using 92 full-resolution CZCS scenes collected along the U.S. northeast coast (NEC) from 1979 to 1986. CZCS pigment was estimated using the standard CZCS two channel bio-optical algorithm and seven sets of AOTR values including individual ratios computed interactively for each NEC image using the ''clear water'' radiance technique (INDIVID); means of the individual NEC ratios (NECAVE, N = 92); means of individual ratios computed from Middle Atlantic Eight (MAB) and NEC scenes (NECMAB, N = 276); means of individual ratios computed from South Atlantic Eight (SAB), MAB and NEC scenes (ECOAST, N = 1091); ''default'' values for global marine aerosols (GLOBAL); and time-varying ratios derived from weak annual signals present in the individual ratios used to compute NECMAB and ECOAST means. Precision was estimated using geometric mean CZCS pigment values computed from the seven sets of images for three 70 x 70 km sub-domains located in the western Gulf of Maine, on southern Georges Bank and over the continental slope. The smallest root mean square difference (RMSD) for geometric mean CZCS pigment (<0.05 log(10) units) was obtained between images processed using means of individual ratios and time-varying ratios, while the largest RMSD (generally >0.1 log(10) units) was obtained between images processed using GLOBAL and INDIVID ratios. Accuracy was estimated using geometric mean CZCS pigment values computed from the seven sets of images and a sea truth data set. After removal of suspect CZCS pigment values, agreement between CZCS pigment and sea truth data was highest using ECOAST mean ratios and a spatial window diameter (temporal window) of 7 km (+/-0.5 days) for N = 546, displaying RMSD (log(10) units), linear regression slope and correlation coefficient of 0.19, 1.00 and 0.88, respectively. ECOAST ''mean'' AOTR values resulted in a superior atmospheric correction for computation of CZCS pigment values from the Georges Bank-Gulf of Maine region when compared with values computed using ''default'' global or individual ''interactively determined'' ratios. ECOAST mean AOTR values should provide a consistent regional atmospheric correction for all CZCS scenes from the Georges Bank-Gulf of Maine region, including scenes which lack low pigment water and therefore cannot make use of the ''clear-water'' radiance technique. C1 UNIV RHODE ISL, GRAD SCH OCEANOG, NARRAGANSETT, RI 02882 USA. RP Bisagni, JJ (reprint author), NOAA, NATL MARINE FISHERIES SERV, NE FISHERIES SCI CTR, NARRAGANSETT, RI 02882 USA. NR 41 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0278-4343 EI 1873-6955 J9 CONT SHELF RES JI Cont. Shelf Res. PD MAY PY 1997 VL 17 IS 6 BP 635 EP + DI 10.1016/S0278-4343(96)00056-8 PG 0 WC Oceanography SC Oceanography GA WL707 UT WOS:A1997WL70700003 ER PT J AU Schlangen, E Garboczi, EJ AF Schlangen, E Garboczi, EJ TI Fracture simulations of concrete using lattice models: Computational aspects SO ENGINEERING FRACTURE MECHANICS LA English DT Article ID COMPUTER-SIMULATION; CRACK-PROPAGATION; BRITTLE-FRACTURE; ELASTIC FRACTURE; PERCOLATION; COMPOSITES; BREAKDOWN; NETWORKS; SOLIDS AB This paper addresses some lattice model techniques used in numerical simulations of fracture in concrete and other random materials. The influence of lattice element type and lattice orientation on the fracture pattern was investigated by simulating a shear loading experiment on a concrete plate. Beam elements with three degrees of freedom per node, and with a random orientation of the beams within the lattice, gave the best comparison with experiment. The effect of element resolution on fracture results was also investigated. A new fracture law has been developed that uses principal tensile stresses in each node of the lattice to determine which beam should break at every step of a simulation. For the implementation of heterogeneity in the model, a method has been developed that uses digital images of the real microstructure of a material. Simulated crack patterns were obtained for a real material, using this technique, which appear quite realistic. Published by Elsevier Science Ltd. C1 NATL INST STAND & TECHNOL,BLDG MAT DIV,GAITHERSBURG,MD 20899. RP Schlangen, E (reprint author), INTRON SME,POB 226,NL-3990 GA HOUTEN,NETHERLANDS. RI Schlangen, Erik/A-3287-2009 NR 41 TC 242 Z9 284 U1 5 U2 48 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD MAY-JUN PY 1997 VL 57 IS 2-3 BP 319 EP 332 DI 10.1016/S0013-7944(97)00010-6 PG 14 WC Mechanics SC Mechanics GA XJ917 UT WOS:A1997XJ91700008 ER PT J AU Caira, JN Benz, GW Borucinska, J Kohler, NE AF Caira, JN Benz, GW Borucinska, J Kohler, NE TI Pugnose eels, Simenchelys parasiticus (Synaphobranchidae) from the heart of a shortfin mako, Isurus oxyrinchus (Lamnidae) SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE shark; scavenger; facultative parasite; parasitic fish AB A 395 kg shortfin mako, Isurus oxyrinchus (Lamnidae) landed at Montauk, New York in June of 1992 was found to contain two dead, but otherwise healthy appearing pugnose eels, Simenchelys parasiticus (Synaphobranchidae) within the lumen of its heart. The path along which the eels made their way into the shark's heart was not found. Histological examination of the shark's heart revealed the presence of medial hyperplasia and hypertrophy of small arterioles, multifocal arteriosclerosis, and relatively high numbers of capillaries per unit area. These phenomena were not observed in similar sections taken from hearts of six uninfected mako sharks. The stomachs of both eels were filled with blood, suggesting that they had been within the shark at least long enough to feed. Consideration of this new record along with the literature supports a trophic designation of facultative endoparasite for the species Simenchelys parasiticus. C1 TENNESSEE AQUARIUM,CHATTANOOGA,TN 37401. UNIV CONNECTICUT,DEPT PATHOBIOL,STORRS,CT 06269. NATL MARINE FISHERIES SERV,NE FISHERIES SCI CTR,NARRAGANSETT,RI 02882. RP Caira, JN (reprint author), UNIV CONNECTICUT,DEPT ECOL & EVOLUTIONARY BIOL,STORRS,CT 06269, USA. NR 22 TC 8 Z9 9 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD MAY PY 1997 VL 49 IS 1 BP 139 EP 144 DI 10.1023/A:1007398609346 PG 6 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA WZ357 UT WOS:A1997WZ35700016 ER PT J AU Beliaeff, B OConnor, TP Daskalakis, DK Smith, PJ AF Beliaeff, B OConnor, TP Daskalakis, DK Smith, PJ TI US Mussel Watch data from 1986 to 1994: Temporal trend detection at large spatial scales SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article AB National Mussel Watch Programs collect bivalves at many sites along their respective coastlines in order to assess chemical contamination of coastal waters. This paper aims at detecting temporal trends at large spatial scales using contaminant data from 1986 to 1994 of the U.S. National Status and Trends Mussel Watch Program. U.S. coasts are divided into 10 large areas. After a logarithmic transformation of the data, linear models are used and include a 'sampling site' effect, a linear trend estimated for each area, weather covariates, and an 'analysis' effect reflecting changes of analytical procedures or even laboratories. Except for the Californian coast, chlorinated organic compounds show rather uniform decreases, which can be attributed to bans put on these contaminants. A few in creasing trends were detected for trace elements, which also showed few decreases. Additions of weather covariates and possible analysis effects were intended to model apparently random between-year variations in contaminant time-series. Although low in terms of percentage of variability explained, the addition of these effects might have avoided the detection of spurious trends for some contaminants. C1 NOAA, NORCA21, SILVER SPRING, MD 20910 USA. IFREMER, F-44311 NANTES 03, FRANCE. UNIV MARYLAND, DEPT MATH, COLLEGE PK, MD 20742 USA. NR 9 TC 40 Z9 43 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X EI 1520-5851 J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY PY 1997 VL 31 IS 5 BP 1411 EP 1415 DI 10.1021/es9606586 PG 5 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA WW948 UT WOS:A1997WW94800038 ER PT J AU Jones, WW AF Jones, WW TI The evolution of HAZARD, the fire hazard assessment methodology SO FIRE TECHNOLOGY LA English DT Article DE fire modeling; building design; fire growth; smoke movement AB The United States alone spends about $700 billion a year on new and renovated construction. About 20% of this money assures safety from unwanted fires, and this portion includes the cost of insurance to families and businesses. This enormous cost could be reduced by introducing fire safe products to the building and transportation industries, both in the United States and abroad, and by introducing advanced detectors, suppression systems, and firefighting equipment to the fire protection industry. In order to show that these products and mechanisms are safe to use, industries need performance measures. Performance-based fire standards are currently being developed to augment prescriptive standards around the world. Performance-based standards are intended to provide flexibility in maintaining accept; ed fire safety levels among competitive products, while ensuring life safety and reducing property loss. At the same time, performance-based requirements should reduce design and construction costs, as well as the cost of maintenance and liability coverage. In order to derive these benefits, evaluation tools are needed. One such tool, HAZARD I, helps users understand the consequences of unwanted fires by making the results of recent fire research available to them. Improvements to the program will include increased applicability, improved usability, the ability to address additional building features, and more accurate treatment of fire behavior and its effects on people and their actions. Many of the improvements made already in the software documentation ate based on the experience of fire protection engineers and others who have used the program. User input, combined with other planned program improvements, constitute the first step in the overall goal of a complete Fire Hazard assessment methodology. RP Jones, WW (reprint author), NATL INST STAND & TECHNOL,BLDG & FIRE RES LAB,FIRE MODELING & APPLICAT GRP,GAITHERSBURG,MD 20899, USA. NR 13 TC 1 Z9 1 U1 1 U2 2 PU NATIONAL FIRE PROTECTION ASSOC PI QUINCY PA ONE BATTERYMARCH PK, QUINCY, MA 02269 SN 0015-2684 J9 FIRE TECHNOL JI Fire Technol. PD MAY-JUN PY 1997 VL 33 IS 2 BP 167 EP 182 DI 10.1023/A:1015399118241 PG 16 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA XE877 UT WOS:A1997XE87700005 ER PT J AU Tuovinen, H Cooper, LY AF Tuovinen, H Cooper, LY TI Validation of ceiling jet flows in a large corridor with vents using the CFD code JASMINE: Errata and additional remarks SO FIRE TECHNOLOGY LA English DT Article AB This paper identifies and corrects errata and provides additional clarifying remarks on the previously published paper.(1) C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Tuovinen, H (reprint author), SWEDISH NATL TESTING & RES INST,BORAS,SWEDEN. NR 5 TC 1 Z9 1 U1 0 U2 2 PU NATIONAL FIRE PROTECTION ASSOC PI QUINCY PA ONE BATTERYMARCH PK, QUINCY, MA 02269 SN 0015-2684 J9 FIRE TECHNOL JI Fire Technol. PD MAY-JUN PY 1997 VL 33 IS 2 BP 183 EP 186 DI 10.1023/A:1015351202311 PG 4 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA XE877 UT WOS:A1997XE87700006 ER PT J AU Tobler, RL Hwang, IS Steeves, MM AF Tobler, RL Hwang, IS Steeves, MM TI Fracture mechanics behavior of a Ni-Fe superalloy sheath for superconducting fusion magnets .1. property measurements SO FUSION ENGINEERING AND DESIGN LA English DT Article ID CRACK AB A seamless extruded conduit for superconductor cabling was fabricated and subjected to mechanical tests. The conduit is made of a nickel-iron alloy having aging and thermal contraction characteristics comparable with Nb3Sn conductors. The conduit in liquid helium at 4 K retains its ductility and offers high strength, toughness, and fatigue resistance. Specimens with surface cracks in tension offer substantial fracture resistance for the practical case of crack propagation in the through-wall direction. Fatigue tests indicate that surface cracks adopt a nearly semicircular shape as they grow through the conduit wall (L-S orientation) at rates in the power-law region that are no faster than rates in the transverse direction (L-T orientation). The serviceability of this material is discussed. C1 SEOUL NATL UNIV,SEOUL 151742,SOUTH KOREA. MIT,CAMBRIDGE,MA 02139. RP Tobler, RL (reprint author), NATL INST STAND & TECHNOL,325 BROADWAY,BOULDER,CO 80303, USA. NR 20 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD MAY PY 1997 VL 36 IS 2-3 BP 251 EP 267 DI 10.1016/S0920-3796(96)00701-6 PG 17 WC Nuclear Science & Technology SC Nuclear Science & Technology GA XN658 UT WOS:A1997XN65800006 ER PT J AU Kim, JH Hwang, IS Tobler, RL AF Kim, JH Hwang, IS Tobler, RL TI Fracture mechanics behavior of a Ni-Fe superalloy sheath for superconducting fusion magnets .2. magnet life analysis model SO FUSION ENGINEERING AND DESIGN LA English DT Article AB From previous results of fatigue crack growth and fracture toughness measurements for a Ni-Fe base superalloy, a primary candidate for the International Thermonuclear Experimental Reactor (ITER) central solenoid (CS) conduit, we derive an improved magnet life analysis model from the framework of Newman and Raju. For the superalloy conduit with an initial semielliptical surface crack in its thickness direction, the model predicts the evolution of crack aspect ratio for a wide range of initial crack geometries under pure tension and bending fatigue. The prediction of final fracture due to fatigue crack growth using the linear elastic fracture mechanics approach is shown to be underconservative. An alternative model based on Newman's elastic-plastic fracture toughness parameter is derived for the base metal with nearly semicircular cracks. The improved life analysis model taking into account the fatigue and fracture behavior is applied to the ITER CS magnet and the results are compared with those from earlier models. Accounting for the crack shape evolution leads to significantly longer life compared to assuming a constant aspect ratio. For the superalloy base metal we find that the expected fatigue life of Engineering Design Activity (EDA) design of the CS magnet is about eight times the design requirement. Even the Conceptual Design Activity (CDA) design with a free-standing CS meets the life requirement when analyzed by the improved model. C1 SEOUL NATL UNIV,DEPT NUCL ENGN,SEOUL 151742,SOUTH KOREA. NATL INST STAND & TECHNOL,DIV MAT RELIABIL,BOULDER,CO 80303. NR 10 TC 1 Z9 1 U1 1 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD MAY PY 1997 VL 36 IS 2-3 BP 269 EP 279 DI 10.1016/S0920-3796(97)00006-9 PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA XN658 UT WOS:A1997XN65800007 ER PT J AU Maestro, MA Planas, JV Moriyama, S Gutierrez, J Planas, J Swanson, P AF Maestro, MA Planas, JV Moriyama, S Gutierrez, J Planas, J Swanson, P TI Ovarian receptors for insulin and insulin-like growth factor I (IGF-I) and effects of IGF-I on steroid production by isolated follicular layers of the preovulatory coho salmon ovarian follicle SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article ID THECA-INTERSTITIAL-CELLS; RAT GRANULOSA-CELLS; GONADOTROPINS GTH-I; ONCORHYNCHUS-KISUTCH; STIMULATING-HORMONE; KINASE-ACTIVITY; TELEOST GONADS; RED SEABREAM; PAGRUS-MAJOR; EXPRESSION AB In this study, receptors for insulin and insulin-like growth factor I (IGF-I) in isolated theca-interstitial layers and granulosa cells of the coho salmon preovulatory ovary were characterized, and the effects of IGF-I on ovarian steroidogenesis were examined. Specific receptors for insulin and IGF-I were found in granulosa and theca-interstitial layers. In both follicular layers, IGF-I receptors were greater in number and higher in affinity than insulin receptors. The effects of IGF-I on in vitro production of testosterone (T) and 17 alpha-hydroxyprogesterone (17OH-P) by theca-interstitial layers and of 17 beta-estradiol (E-2) and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) by granulosa cell layers were evaluated during the preovulatory period. Both human and salmon recombinant IGF-I inhibited the basal and GTH II-stimulated T and 17OH-P production by theca-interstitial layers throughout the preovulatory period. In contrast, IGF-I stimulated the production of both E-2 and 17,20 beta-P by granulosa cell layers prior to germinal vesicle breakdown (GVBD) but only stimulated the production of 17,20 beta-P by granulosa cell layers after GVBD. The inhibitory effects of IGF-I on steroid production by the theca-interstitial layer and the opposite stimulatory effects on steroid production by the granulosa cell layer, coupled by the presence of specific IGF-I receptors in both follicular layers, suggest that IGF-I may play a role in the regulation of steroidogenesis in the preovulatory coho salmon ovary. (C) 1997 Academic Press. C1 UNIV WASHINGTON,SCH FISHERIES,SEATTLE,WA 98195. NW FISHERIES SCI CTR,SEATTLE,WA 98112. RP Maestro, MA (reprint author), UNIV BARCELONA,DEPT BIOCHEM & PHYSIOL,E-08028 BARCELONA,SPAIN. RI Gutierrez, Joaquim/H-2836-2015 OI Gutierrez, Joaquim/0000-0002-3126-2236 NR 53 TC 68 Z9 70 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0016-6480 J9 GEN COMP ENDOCR JI Gen. Comp. Endocrinol. PD MAY PY 1997 VL 106 IS 2 BP 189 EP 201 DI 10.1006/gcen.1996.6863 PG 13 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA WY519 UT WOS:A1997WY51900006 PM 9169115 ER PT J AU Takasaki, N Yamaki, T Hamada, M Park, L Okada, N AF Takasaki, N Yamaki, T Hamada, M Park, L Okada, N TI The salmon SmaI family of short interspersed repetitive elements (SINEs): Interspecific and intraspecific variation of the insertion of SINEs in the genomes of chum and pink salmon SO GENETICS LA English DT Article ID RNA-DERIVED RETROPOSONS; ALU-SEQUENCES; DNA-SEQUENCE; EVOLUTION; AMPLIFICATION; INTROGRESSION; HYBRIDIZATION; TRANSCRIPTION; EUKARYOTES; PHYLOGENY AB The genomes of chum salmon and pink salmon contain a family of short interspersed repetitive elements (SINEs), designated the salmon SmaI family. It is restricted to these two species, a distribution that suggests that this SINE family might have been generated in their common ancestor. When insertions of the SmaI SINEs at 10 orthologous loci of these species were analyzed, however, it was found that there were no shared insertion sites between chum and pink salmon. Furthermore, at six loci where SmaI SINEs have been species-specifically inserted in chum salmon, insertions of SINEs were polymorphic among populations of chum salmon. By contrast, at four loci where SmaI SINEs had been species-specifically inserted in pink salmon, the SINEs were fixed among all populations of pink salmon. The interspecific and intraspecific variation of the SmaI SINEs cannot be explained by the assumption that the SmaI family was amplified in a common ancestor of these two species. To interpret these observations, we propose several possible models, including introgression and the horizontal transfer of SINEs from pink salmon to chum salmon during evolution. C1 TOKYO INST TECHNOL,FAC BIOSCI & BIOTECHNOL,MIDORI KU,YOKOHAMA,KANAGAWA 226,JAPAN. NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,COASTAL ZONE & ESTUARINE STUDIES DIV,SEATTLE,WA 98112. NR 50 TC 29 Z9 29 U1 0 U2 0 PU GENETICS PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202 SN 0016-6731 J9 GENETICS JI Genetics PD MAY PY 1997 VL 146 IS 1 BP 369 EP 380 PG 12 WC Genetics & Heredity SC Genetics & Heredity GA WW880 UT WOS:A1997WW88000030 PM 9136025 ER PT J AU Sackett, WM Conkright, ME AF Sackett, WM Conkright, ME TI Summary and re-evaluation of the high-temperature isotope geochemistry of methane SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID CARBON; EXCHANGE; KEROGEN AB Thirty years of research are brought together into one coherent summary of carbon and hydrogen isotope effects during the thermocatalytic production of methane from model compounds, petroleum, source rocks, and coals. The approach used by the authors and co-workers has been to pyrolyze model and natural compounds and to study the isotopic fractionations associated with molecular structure, temperature, and catalysis. The results from these experiments are summarized. A practical application of these pyrolysis experiments was the development of the pyrolysis-carbon isotope method (PCM) for determining kerogen maturity. This maturity indexing procedure is based on the isotopic difference between the total methane produced by exhaustive pyrolysis and the parent organic carbon and the mole ratio of methane to parent carbon. Data are also summarized for the thermal destruction of methane and carbon isotope exchange between methane and amorphous carbon and carbon dioxide. The latter results are important when determining the source of methane in hydrothermal fluids. Copyright (C) 1997 Elsevier Science Ltd. C1 NOAA,NODC,OCEAN CLIMATE LAB EOC5,SILVER SPRING,MD. RP Sackett, WM (reprint author), UNIV S FLORIDA,DEPT MARINE SCI,ST PETERSBURG,FL 33701, USA. NR 28 TC 3 Z9 3 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 1997 VL 61 IS 9 BP 1941 EP 1952 DI 10.1016/S0016-7037(97)00039-2 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XA887 UT WOS:A1997XA88700015 ER PT J AU Hoerling, MP Kumar, A AF Hoerling, MP Kumar, A TI Why do North American climate anomalies differ from one El Nino event to another? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB This study explores the cause of the appreciable North American climate from one El Nino event to another. Two competing sources of inter-El Nino variations are examined; one associated with differences in sea surface temperature (SST) forcing between El Nino events, and the other associated with purely internal atmospheric processes that operate independently of El Nino. The analysis is based upon a large ensemble of atmospheric general circulation model (AGCM) simulations that are forced with the observed variations in global SSTs during 1950-1994. From investigation of the seven strongest warm events in this record, the AGCM is shown to possess only one dominant large-scale pattern over the Pacific-North American region. The case-to-case variability seen in nature is thus claimed to be primarily due to atmospheric processes, and the inter-El Nino differences in SST appear to be of secondary importance. The significance of these results for an atmosphere-ocean forecasting system are discussed. C1 NOAA,NCEP,ENVIRONM MODELING CTR,CAMP SPRINGS,MD. RP Hoerling, MP (reprint author), UNIV COLORADO,CIRES,CLIMATE DIAGNOST CTR,BOULDER,CO 80309, USA. NR 10 TC 50 Z9 50 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1997 VL 24 IS 9 BP 1059 EP 1062 DI 10.1029/97GL00918 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WX269 UT WOS:A1997WX26900015 ER PT J AU Hanson, DR AF Hanson, DR TI Reaction of N2O5 with H2O on bulk liquids and on particles and the effect of dissolved HNO3 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SULFURIC-ACID PARTICLES; SULFATE AEROSOLS; CLONO2; OZONE; SOLUBILITIES; KINETICS; HCL AB Measurements of the reaction probability (gamma) of N2O5 on similar to 60 wt % H2SO4 were performed at 201 to 230 K on bulk liquids and at 230 K on aerosol particles. The bulk and aerosol results are in good agreement (less than 10% difference). The measurements on bulk liquids show very little change in gamma with temperature from 201 to 230 K. HNO3 was added to the bulk liquids at similar to 201 K and to aerosol particles at 230 K (the H2SO4-content was decreased to keep water activity approximately constant). For [HNO3] levels of 1-to-15 wt %, the N2O5 reaction probability decreased by similar to 15 % from that measured on HNO3-free 60 wt% H2SO4. For 60 wt% H2SO4 aerosol in the stratosphere ([HNO3] similar to 0.3 wt%) the decrease in the N2O5 hydrolysis reaction probability due to HNO3 would be small. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO. RP Hanson, DR (reprint author), NOAA,AERON LAB,R-E-AL2,325 BROADWAY,BOULDER,CO 80303, USA. NR 28 TC 26 Z9 26 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1997 VL 24 IS 9 BP 1087 EP 1090 DI 10.1029/97GL00917 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WX269 UT WOS:A1997WX26900022 ER PT J AU Talukdar, RK Gilles, MK BattinLeclerc, F Ravishankara, AR Fracheboud, JM Orlando, JJ Tyndall, GS AF Talukdar, RK Gilles, MK BattinLeclerc, F Ravishankara, AR Fracheboud, JM Orlando, JJ Tyndall, GS TI Photolysis of ozone at 308 and 248 nm: Quantum yield of O(D-1) as a function of temperature SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID O-2(A(1)DELTA(G)); O-3 AB The quantum yield of O(D-1), Phi(T), in the 308 nm photolysis of ozone has been shown to decrease very slightly with temperature (T), from 0.79+/-0.10 at 298 K to 0.73+/-0.10 at 200 K. At 248 nm, Phi is (0.91+/-0.06) independent of temperature (200-320 K). The rate constant for the reaction of O(1D) with O-3 was measured to be (2.3+/-0.5)x10(-10) cm(3) molecule(-1) s(-1), independent of temperature (200-350 K). The measured quantum yields suggest that the current recommendations over-estimate the effect of temperature on O(D-1) quantum yields in O-3 photolysis at 308 nm. C1 NATL CTR ATMOSPHER RES,DIV ATMOSPHER CHEM,BOULDER,CO 80307. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. CNRS,ENSIC,DCPR,F-54001 NANCY,FRANCE. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. RP Talukdar, RK (reprint author), NOAA,AERON LAB,R-E-AL2,325 BROADWAY,BOULDER,CO 80303, USA. RI TALUKDAR, RANAJIT/G-4530-2013; Ravishankara, Akkihebbal/A-2914-2011 OI TALUKDAR, RANAJIT/0000-0001-6017-8431; NR 19 TC 26 Z9 27 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1997 VL 24 IS 9 BP 1091 EP 1094 DI 10.1029/97GL00831 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WX269 UT WOS:A1997WX26900023 ER PT J AU Reid, GC AF Reid, GC TI On the influence of electrostatic charging on coagulation of dust and ice particles in the upper mesosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NOCTILUCENT CLOUDS; MST RADAR; DENSITY AB The upper mesosphere, at heights above about 80 km, is the region of the atmosphere in which most ablation of incoming meteoric material takes place, and is thought to contain tiny nanometer-size smoke and dust particles with concentrations of several thousand per cubic centimeter. In the extremely cold summer conditions at high latitudes, these particles probably form the condensation nuclei on which ice particles grow, giving rise to a variety of unique phenomena, including noctilucent clouds and localized electron depletions (''biteouts''). Recent work has shown that the particles become electrically charged by scavenging free electrons and positive ions from the background ionosphere. Under normal daytime conditions, calculations of charge balance have shown that most of the particles will carry a single negative charge, and it has been pointed out that electrostatic repulsion will inhibit coagulation of the particles, which would otherwise be an important mechanism for their growth. It is shown here that the opposite is true when ionization rates are very low, for example at night in the absence of energetic-particle precipitation. In this case, positively and negatively charged particles tend to exist in equal numbers, and coagulation is enhanced by charging, instead of being inhibited. Because of the major unknown factors other than charging that affect coagulation, only idealized semi-quantitative estimates of coagulation rates can be made. Electrical charging, however, appears to be a much less serious barrier to coagulation than had been thought, and may actually be a powerful stimulant. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Reid, GC (reprint author), NOAA,ERL,AERON LAB,BOULDER,CO 80303, USA. NR 15 TC 27 Z9 27 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1997 VL 24 IS 9 BP 1095 EP 1098 DI 10.1029/97GL00922 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WX269 UT WOS:A1997WX26900024 ER PT J AU Williams, J Roberts, JM Fehsenfeld, FC Bertman, SB Buhr, MP Goldan, PD Hubler, G Kuster, WC Ryerson, TB Trainer, M Young, V AF Williams, J Roberts, JM Fehsenfeld, FC Bertman, SB Buhr, MP Goldan, PD Hubler, G Kuster, WC Ryerson, TB Trainer, M Young, V TI Regional ozone from biogenic hydrocarbons deduced from airborne measurements of PAN, PPN, and MPAN SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GAS-PHASE REACTION; METHYL VINYL KETONE; NATURAL HYDROCARBONS; ORGANIC NITRATES; UNITED-STATES; METHACROLEIN; ISOPRENE; SITE; OXIDATION; HYDROXYL AB NOx-catalyzed production of ozone over large regions of North America and Europe is a serious air quality problem that often involves biogenic hydrocarbons, mainly isoprene. Peroxy-methacrylic nitric anhydride (MPAN, CH2C(CH3)C(O)OONO2) is formed uniquely from isoprene-NOx photochemistry hence is an indicator of recent ozone production from isoprene. Presented here are the first airborne measurements of MPAN along with PAN (peroxyacetic nitric anhydride, CH3C(O)OONO2), PPN (peroxypropionic nitric anhydride, CH3CH2C(O)OONO2) and ozone measurements. Relationships between these species are used to estimate the contributions of anthropogenic and biogenic hydrocarbons (BHC) to regional tropospheric ozone production, providing direct evidence of ozone production from BHC-NOx photochemistry. C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. YORK UNIV,N YORK,ON M3J 1P3,CANADA. RP Williams, J (reprint author), NOAA,ERL,AERON LAB,BOULDER,CO 80303, USA. RI Roberts, James/A-1082-2009; Kuster, William/E-7421-2010; Hubler, Gerhard/E-9780-2010; Trainer, Michael/H-5168-2013; Ryerson, Tom/C-9611-2009; Fehsenfeld, Frederick/I-4876-2013 OI Roberts, James/0000-0002-8485-8172; Kuster, William/0000-0002-8788-8588; NR 25 TC 87 Z9 90 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1997 VL 24 IS 9 BP 1099 EP 1102 DI 10.1029/97GL00548 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WX269 UT WOS:A1997WX26900025 ER PT J AU Williams, DF AF Williams, DF TI Multiconductor transmission line characterization SO IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY PART B-ADVANCED PACKAGING LA English DT Article DE coupling; electromagnetic modes; measurement; microstrip; multiconductor transmission line AB This paper presents a measurement method that completely characterizes lossy printed multiconductor transmission lines. It determines not only the matrices of impedances and admittances per unit length describing the transmission line in the conductor representation, but also the propagation constants, characteristic impedances, and cross-powers for each mode supported in the line. We apply the method to a pair of lossy coupled asymmetric microstrip lines. RP Williams, DF (reprint author), NATL INST STAND & TECHNOL,BOULDER,CO 80303, USA. NR 15 TC 13 Z9 13 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1070-9894 J9 IEEE T COMPON PACK B JI IEEE Trans. Compon. Packag. Manuf. Technol. Part B-Adv. Packag. PD MAY PY 1997 VL 20 IS 2 BP 129 EP 132 DI 10.1109/96.575563 PG 4 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA WX691 UT WOS:A1997WX69100003 ER PT J AU Suehle, JS Chaparala, P AF Suehle, JS Chaparala, P TI Low electric field breakdown of thin SiO2 films under static and dynamic stress SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article ID DEPENDENT DIELECTRIC-BREAKDOWN; SIO2-FILMS; SILICON; OXIDES; DEGRADATION; RELIABILITY AB A comprehensive study of Time-Dependent Dielectric Breakdown (TDDB) of 6.5-, 9-, 15-, and 22-nm SiO2 films under de and pulsed bias has been conducted over a wide range of electric fields and temperatures, Very high temperatures were used at the wafer level to accelerate breakdown so tests could be conducted at electric fields as low as 4.5 MV/cm. New observations are reported for TDDB that suggest a consistent electric field and temperature dependence for intrinsic breakdown and a changing breakdown mechanism as a function of electric field, The results show that the logarithm of the median-test-time-to failure, log (ta), is described by a linear electric field dependence with a field acceleration parameter that is not dependent on temperature, It has a value of approximately 1 decade/MV/cm for the range of oxide thicknesses studied and shows a slight decreasing trend with decreasing oxide thickness, The thermal activation E-a ranged between 0.7 and 0.95 eV for electric fields below 9.0 MV/cm for all oxide thicknesses, TDDB tests conducted under pulsed bias indicate that increased dielectric lifetime is observed under unipolar and bipolar pulsed stress conditions, but diminishes as the stress electric field and oxide thickness are reduced, This observation provides new evidence that low electric field aging and breakdown is not dominated by charge generation and trapping. C1 UNIV MARYLAND,CTR RELIABIL ENGN,COLLEGE PK,MD 20742. RP Suehle, JS (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 30 TC 75 Z9 75 U1 0 U2 10 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 1997 VL 44 IS 5 BP 801 EP 808 DI 10.1109/16.568042 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA WV648 UT WOS:A1997WV64800017 ER PT J AU Haddad, ZS Short, DA Durden, SL Im, E Hensley, S Grable, MB Black, RA AF Haddad, ZS Short, DA Durden, SL Im, E Hensley, S Grable, MB Black, RA TI A new parametrization of the rain drop size distribution SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID RADAR AB This paper revisits the problem of finding a parametric form for the rain drop size distribution (DSD) which 1) is an appropriate model for tropical rainfall, and 2) involves statistically independent parameters, Using TOGA/COARE data, we derive a parametrization which meets these criteria, This new parametrization is an improvement on the one that was derived in [3], using TRMM ground truth data from Darwin, Australia, The new COARE data allows us to verify that the spatial variability of the two ''shape'' parameters is relatively small, thus confirming that this parametrization should be particularly useful for remote sensing applications, We also derive new DSD-based radar-reflectivity-rain-rate power laws, whose coefficients are directly related to the shape parameters of the DSD, Perhaps most important, since the coefficients are independent of the rain-rate itself, and vary little spatially, the relations are ideally suited for rain retrieval algorithms, It should also prove straightforward to extend this method to the problems of estimating cloud hydrometeors from remote-sensing measurements. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. NOAA, ATLANTIC OCEANOG & METEOROL LAB, MIAMI, FL 33149 USA. RP Haddad, ZS (reprint author), CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RI Black, Robert/C-9617-2009 OI Black, Robert/0000-0001-6938-125X NR 15 TC 82 Z9 82 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1997 VL 35 IS 3 BP 532 EP 539 DI 10.1109/36.581961 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA WZ433 UT WOS:A1997WZ43300004 ER PT J AU Milanovic, V Gaitan, M Bowen, ED Zaghloul, ME AF Milanovic, V Gaitan, M Bowen, ED Zaghloul, ME TI Micromachined microwave transmission lines in CMOS technology SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE CMOS microwave elements; coplanar waveguides; maskless etching; micromachining; MOSIS; suspended transmission lines ID NETWORK ANALYZER AB Coplanar waveguides were designed and fabricated through a commercial CMOS process with post-processing micromachining. The transmission-line layouts were designed with commercial computer-aided design (CAD) tools. Integrated circuits (IC's) were fabricated through the MOSIS service; and subsequently suspended by top-side etching. The absence of the lossy silicon substrate after etching results in significantly improved insertion-loss characteristics, dispersion characteristics, and phase velocity. Two types of layout sire presented for different ranges of characteristic impedance. Measurements of the waveguides both before and after micromachining were performed at frequencies from 1 to 40 GHz using a vector network analyzer and de-embedding techniques, showing improvement Of loss characteristics of orders of magnitude. For the entire range of frequencies, for the 50-Omega layout, losses do not exceed 4 dB/cm. These losses are mainly due to the small width and thickness of the metal strips. Before etching, losses are as high as 38 dB/cm due to currents in the underlying substrate. Phase velocity in the micromachined transmission lines is close to that in free spare. C1 NIST, DIV SEMICOND ELECT, GAITHERSBURG, MD 20899 USA. RF MICROSYST INC, SAN DIEGO, CA 92111 USA. RP GEORGE WASHINGTON UNIV, DEPT ELECT ENGN & COMP SCI, WASHINGTON, DC 20052 USA. NR 17 TC 58 Z9 64 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9480 EI 1557-9670 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD MAY PY 1997 VL 45 IS 5 BP 630 EP 635 DI 10.1109/22.575577 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA WY199 UT WOS:A1997WY19900007 ER PT J AU Mantooth, HA Hefner, AR AF Mantooth, HA Hefner, AR TI Electrothermal simulation of an IGBT PWM inverter SO IEEE TRANSACTIONS ON POWER ELECTRONICS LA English DT Article DE electrothermal; IGBT; inverter; modeling; pulse-width modulation; simulation ID MODEL AB A recently developed electrothermal network simulation methodology is used to analyze the behavior of a full-bridge, pulse-width-modulated (PWM), voltage-source inverter, which uses insulated gate bipolar transistors (IGBT's) as the switching devices, The electrothermal simulations are performed using the Saber circuit simulator and include control logic circuitry, IGBT gate drivers, the physics-based IGBT electrothermal model, and thermal network component models for the power-device silicon chips, packages, and heat sinks. It is shown that the thermal response of the silicon chip determines the IGBT temperature rise during the device switching cycle, The thermal response of the device TO247 package and silicon chip determines the device temperature rise during a single phase of the 60-Hz sinusoidal output, Also, the thermal response of the heat sink determines the device temperature rise during the system startup and after load-impedance changes, It is also shown that the full electrothermal analysis Is required to accurately describe the power losses and circuit efficiency. C1 NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Mantooth, HA (reprint author), ANAL INC,BEAVERTON,OR 97075, USA. NR 11 TC 44 Z9 48 U1 0 U2 15 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8993 J9 IEEE T POWER ELECTR JI IEEE Trans. Power Electron. PD MAY PY 1997 VL 12 IS 3 BP 474 EP 484 DI 10.1109/63.575675 PG 11 WC Engineering, Electrical & Electronic SC Engineering GA WX695 UT WOS:A1997WX69500011 ER PT J AU Cresswell, MW Allen, RA Linholm, LW Guthrie, WF Penzes, WB Gurnell, AW AF Cresswell, MW Allen, RA Linholm, LW Guthrie, WF Penzes, WB Gurnell, AW TI Hybrid optical-electrical overlay test structure SO IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING LA English DT Article; Proceedings Paper CT 1996 IEEE International Conference on Microelectronic Test Structures (ICMTS 1996) CY MAR 25-28, 1996 CL TRENT, ITALY SP IEEE, Electron Devices Soc AB This paper describes the exploratory use of electrical test structures to enable the calibration of optical overlay instruments of the type used to monitor semiconductor-device fabrication processes, Such optical instruments are known to be vulnerable to hard-to-determine systematic process- and instrument-specific errors known as shifts.(1) However, these shift errors generally do not affect electrical test-structure measurements extracted from the same features.(2) Thus the opportunity exists to configure physical standards having overlay that can be certified by electrical means, thereby enabling estimates of the shifts prevailing in a particular application, In this work, a new hybrid test structure, meaning one from which overlay measurements can be extracted electrically, as well as by optical instruments, has been designed and fabricated with built-in overlay values ranging from -60 to +60 nm, A selection of structures constituting a test chip has been patterned in a single conducting film with CD (critical dimension) design rules ranging from 1.0 mu m to 2.0 mu m and fabricated and tested, Electrical overlay parameters, derived from multiple step-and-repeat die-site measurements, generally match the corresponding optical measurements to within several nanometers, subject to limitations of the pattern-replication process, This paper focuses on the extraction of overlay from the electrical measurements, the dependence of the measurements on CD design rules, and their comparison with the corresponding measurements made both by a commercial optical-overlay instrument and by a coordinate-measurement system having measurements traceable to absolute dimensional standards, It is presented as a first step toward the use of electrical measurements for advancing shift management in optical overlay of features patterned in separate lithographic processes. C1 BIORAD SEMICOND,MT VIEW,CA 94043. RP Cresswell, MW (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0894-6507 J9 IEEE T SEMICONDUCT M JI IEEE Trans. Semicond. Manuf. PD MAY PY 1997 VL 10 IS 2 BP 250 EP 255 DI 10.1109/66.572077 PG 6 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA WV976 UT WOS:A1997WV97600009 ER PT J AU Levine, J AF Levine, J TI Incorporating data from a primary frequency standard into a time scale SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article AB It is difficult to combine data from a primary frequency standard with the time-difference measurements that are usually used as input to most time scales because a primary standard usually operates only occasionally on an irregular schedule and because the fundamental output of a primary frequency standard is a frequency rather than a time, and there is often no natural way of inserting this kind of datum into the scale in a manner that is statistically robust. We will present a new time-scale algorithm that seeks to address these problems. We call this frequency-based algorithm AF1, by analogy with the time-based algorithm AT1 that has been used at NIST for many years. Unlike AT1 in which frequency is simply a parameter that specifies how the time of a clock evolves between measurements, however, the frequency of each clock is a fundamental parameter in AF1. This change in focus provides a natural way for incorporating data from a primary frequency standard into the ensemble. We will present the details of the algorithm and results using data from our primary frequency standard, NIST-7. RP Levine, J (reprint author), NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,BOULDER,CO 80303, USA. NR 10 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 SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAY PY 1997 VL 44 IS 3 BP 629 EP 636 DI 10.1109/58.658316 PG 8 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA XB641 UT WOS:A1997XB64100012 ER PT J AU Klein, SA McLinden, MO Laesecke, A AF Klein, SA McLinden, MO Laesecke, A TI An improved extended corresponding states method for estimation of viscosity of pure refrigerants and mixtures SO INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID LA English DT Article DE refrigerant; mixture; viscosity; calculation; design; corresponding state ID THERMODYNAMIC PROPERTIES; TRANSPORT-PROPERTIES; 1,1,1,2-TETRAFLUOROETHANE R134A; FLUIDS; PREDICTION; 2,2-DICHLORO-1,1,1-TRIFLUOROETHANE; PENTAFLUOROETHANE; TEMPERATURES; COEFFICIENTS; FORMULATION AB The extended corresponding states method for calculating the viscosity of pure refrigerants and mixtures is investigated. The accuracy of pure fluid viscosity values is significantly improved by introducing a third shape factor evaluated using available pure fluid viscosity data. A modification to the method of Huber and Ely (Fluid Phase Equilibria, 1992, 80, 45-46) is proposed for estimation of the viscosity of mixtures; this modification eliminates the possibility of discontinuities at the critical point, ensures that the pure component viscosity is provided in the limit of a component mole fraction approaching 1, and improves the overall accuracy of the method. The method has been applied to 12 pure refrigerants including three hydrocarbons and mixtures. The average absolute deviations between the calculated and experimental viscosity values are within 4% for all of the pure fluids and most of the mixtures investigated. Published by Elsevier Science Ltd and IIR. C1 UNIV WISCONSIN,SOLAR ENERGY LAB,MADISON,WI 53706. RP Klein, SA (reprint author), NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,325 BROADWAY,BOULDER,CO 80303, USA. NR 41 TC 42 Z9 47 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0140-7007 J9 INT J REFRIG JI Int. J. Refrig.-Rev. Int. Froid PD MAY PY 1997 VL 20 IS 3 BP 208 EP 217 DI 10.1016/S0140-7007(96)00073-4 PG 10 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA XD848 UT WOS:A1997XD84800006 ER PT J AU Hurly, JJ Schmidt, JW Boyes, SJ Moldover, MR AF Hurly, JJ Schmidt, JW Boyes, SJ Moldover, MR TI Virial equation of state of helium, xenon, and helium-xenon mixtures from speed-of-sound and Burnett P rho T measurements SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE equation-of-state; helium; helium-xenon mixture; speed-of-sound; thermoacoustic refrigerators; thermodynamic properties; virial coefficients; xenon ID THERMOPHYSICAL PROPERTIES; GASEOUS REFRIGERANTS; THERMODYNAMIC PROPERTIES; ACOUSTIC MEASUREMENTS; COEFFICIENTS; APPARATUS; AR; XE AB The virial equation of state was determined for helium, xenon, and helium-xenon mixtures for the pressure and temperature ranges 0.5 to 5 MPa and 210 to 400 K. Two independent experimental techniques were employed: Burnett P rho T measurements and speed-of-sound measurements. The temperature-dependent second and third density virial coefficients For pure xenon and the second and third interaction density virial coefficients For helium-xenon mixtures were determined. The present density virial equations of state for xenon and helium-xenon mixtures reproduce the speed-of-sound data within 0.01% and the P rho T data within 0.02% of the pressures. All the results for helium are consistent, within experimental errors, with recent ab initio calculations, confirming the accuracy of the experimental techniques. C1 NATL INST STAND & TECHNOL,DIV THERMOPHYS,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899. RI Moldover, Michael/E-6384-2013 NR 40 TC 19 Z9 19 U1 0 U2 5 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1997 VL 18 IS 3 BP 579 EP 634 DI 10.1007/BF02575125 PG 56 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA XK364 UT WOS:A1997XK36400001 ER PT J AU Hurly, JJ Schmidt, JW Gillis, KA AF Hurly, JJ Schmidt, JW Gillis, KA TI Equation of state and ideal-gas heat capacity of a gaseous mixture of 1,1,1,2-tetrafluoroethane, pentafluoroethane, and difluoromethane SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE Burnett; CF3CH2F; CF3CHF2; CH2F2; difluoromethane; equation of state; gas density; heat capacity; pentafluoroethane; refrigerant; speed of sound; tetrafluoroethane; virial coefficient ID OF-SOUND MEASUREMENTS; THERMOPHYSICAL PROPERTIES; VIRIAL-COEFFICIENTS; THERMODYNAMIC PROPERTIES; SPEED; REFRIGERANTS AB We present the gas-phase equation of state and ideal-gas heat capacity of a ternary mixture (nominal molar concentration) of 1,1,1,2-tetrafluoroethane (35%), pentafluoroethane (30%), and difluoromethane (35%) for temperatures between 260 and 453 K and pressures between 0.05 and 7.7 MPa. These results were based on two very different measurement techniques. The first technique measured the gas density of the mixture in a Burnett apparatus from 313 to 453 K and From 0.2 to 7.7 MPa. The second technique deduced the gas density and ideal-gas heat capacity from high-accuracy speed-of-sound measurements in the mixture at temperatures between 260 and 400 K and at pressures between 0.05 and 1.0 MPa, The data from the two techniques were analyzed together to obtain an equation of state that reproduced the densities From the Burnett technique with a fractional RMS deviation of 0.038%, and it also reproduced the sound speeds with a Fractional RMS deviation of 0.003%. Finally, the results are compared Co a predictive model based on the properties of the pure fluids. RP Hurly, JJ (reprint author), NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,CHEM SCI & TECHNOL LAB,GAITHERSBURG,MD 20899, USA. NR 23 TC 3 Z9 3 U1 1 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1997 VL 18 IS 3 BP 655 EP 681 DI 10.1007/BF02575127 PG 27 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA XK364 UT WOS:A1997XK36400003 ER PT J AU Goodwin, ARH Mehl, JB AF Goodwin, ARH Mehl, JB TI Measurement of the dipole moments of seven partially fluorinated hydrocarbons with a radiofrequency reentrant cavity resonator SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE dipole moment; dielectric constant; electromagnetic resonator; refrigerant; reentrant cavity ID VIRIAL-COEFFICIENTS; REFRIGERANTS AB Equilibrium dipole moments of gaseous pentafluorodimethyl ether (HFE-125), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1,3,3,3-hexanuoropropane (HFC-236Fa), 1,1,2,2,3-pentafluoropropane (HFC-245ca), 1,1,1,2,2-pentanuoropropane (HFC-245fa), and 1,1,1,2,2,3,3,4-octafluorobutane (HFC-338mccq) were obtained from the resonance frequency of a reentrant cavity at temperatures between 250 and 373 K. The electronic contributions to the polarization were determined for each fluid from liquid-phase optical index of refraction measurements at 297 K. C1 NATL INST STAND & TECHNOL,PHYS & CHEM PROPERTIES DIV,GAITHERSBURG,MD 20899. UNIV DELAWARE,DEPT PHYS & ASTRON,NEWARK,DE 19711. NR 14 TC 14 Z9 14 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1997 VL 18 IS 3 BP 795 EP 806 DI 10.1007/BF02575134 PG 12 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA XK364 UT WOS:A1997XK36400010 ER PT J AU Josell, D Cezairliyan, A vanHeerden, D Murray, BT AF Josell, D Cezairliyan, A vanHeerden, D Murray, BT TI An integral solution for thermal diffusion in periodic multilayer materials: Application to iron/copper multilayers SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE copper; interfaces; iron; laser pulse heating; molybdenum; multilayer; thermal diffusivity; thermal pulse heating; thin films ID TEMPERATURE AB A closed-form solution for heat transfer through a periodic multilayer material utilizing a transfer matrix technique is presented. The benefit of this technique for periodic multilayer samples is that the use of eigenvector decomposition significantly simplifies the solution. Experimental results, obtained in the vicinity of 1200 K on samples composed of 10 bilayers of nominally 2/3 mu m copper and 4/3 mu m iron on 75-mu m molybdenum substrates, are presented. RP Josell, D (reprint author), NATL INST STAND & TECHNOL,DIV MET,GAITHERSBURG,MD 20899, USA. NR 19 TC 7 Z9 7 U1 1 U2 3 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAY PY 1997 VL 18 IS 3 BP 865 EP 885 DI 10.1007/BF02575138 PG 21 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA XK364 UT WOS:A1997XK36400014 ER PT J AU Sharpless, KE Schiller, SB Margolis, SA Thomas, JB Iyengar, GV Colbert, JC Gills, TE Wise, SA AF Sharpless, KE Schiller, SB Margolis, SA Thomas, JB Iyengar, GV Colbert, JC Gills, TE Wise, SA TI Certification of nutrients in Standard Reference Material 1846: Infant formula SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article AB In 1996, the National Institute of Standards and Technology (NIST) released Standard Reference Material 1846 (Infant Formula), which can be used as a control material for assigning values to in-house control materials and for validating analytical methods for measurement of proximates, vitamins, and minerals in infant formula and similar matrixes. The SRM was manufactured by preparing a spray-dried formula base containing fat, protein, carbohydrates, and minerals and then combining that formula base with a dry-blend vitamin premix that supplied the vitamins. The Certificate of Analysis for SRM 1846 provides assigned values for concentrations of proximates (fat, protein, etc.), vitamins, and minerals for which product labeling is required by the Infant Formula Act of 1980 and by the Nutrition Labeling and Education Act of 1990. These assigned values were based on agreement of measurements by NIST and/or collaborating laboratories. Certified values are provided for vitamins A (trans), E, C, B-2, and B-6 and niacin. Noncertified values are provided for solids, ash, fat, nitrogen, protein, carbohydrate, calories, vitamin D, delta-tocopherol, gamma-tocopherol, Vitamin B-1, vitamin B-12, folic acid, pantothenic acid, biotin, choline, inositol, calcium, phosphorus, magnesium, iron, zinc, copper, sodium, potassium, and chloride. Information values are provided for iodine, manganese, selenium, and vitamin K. C1 US FDA,CTR FOOD SAFETY & APPL NUTR,WASHINGTON,DC 20204. USDA,BELTSVILLE,MD 20705. RP Sharpless, KE (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 15 TC 42 Z9 42 U1 0 U2 5 PU AOAC INTERNATIONAL PI GAITHERSBURG PA 481 NORTH FREDRICK AVE, STE 500, GAITHERSBURG, MD 20877-2504 SN 1060-3271 J9 J AOAC INT JI J. AOAC Int. PD MAY-JUN PY 1997 VL 80 IS 3 BP 611 EP 621 PG 11 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA XA023 UT WOS:A1997XA02300019 PM 9170657 ER PT J AU Martner, BE AF Martner, BE TI Vertical velocities in a thunderstorm gust front and outflow SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID GRAVITY CURRENT; DOPPLER RADAR; DYNAMICS AB Continuous vertically pointing measurements of a thunderstorm outflow, including its gust front, were obtained with a Doppler radar near New Salem, North Dakota. The measurements provide a high-resolution depiction of the vertical structure of reflectivity and vertical velocity within the gust front, the outflow, and the parent storm. Earlier gust front remote sensing studies have used Doppler observations obtained with low-elevation-angle scans to accurately measure the horizontal flow pattern from which vertical velocities were subsequently estimated by integrating the continuity equation. In contrast, the New Salem case provides direct, rather than derived, Doppler measurement of vertical velocities with better vertical resolution and vastly superior temporal resolution. The gust front's vertical structure is in general agreement with earlier observations and numerical simulations, except that the transition from strong upward to strong downward motion was more abrupt. The maximum updraft, of almost 10 m s(-1), was measured in the gust front at 1.35 km above ground level and was followed by equally strong downward motion only 1 min later at a slightly higher altitude. The observations support the earlier use of the continuity method for deriving the basic pattern of vertical motions in density currents from quasi-horizontal scan data. RP Martner, BE (reprint author), NOAA,ENVIRONM TECHNOL LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 22 TC 10 Z9 13 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 1997 VL 36 IS 5 BP 615 EP 622 DI 10.1175/1520-0450(1997)036<0615:VVIATG>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WZ020 UT WOS:A1997WZ02000017 ER EF