Sample records for oxygen isotope study

  1. An Oxygen Isotope Study Of Silicates In The Larderello Geothermal...

    Open Energy Info (EERE)

    Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: An Oxygen Isotope Study Of Silicates In The Larderello Geothermal Field, Italy Abstract...

  2. IN-SITU STUDY OF OXYGEN ISOTOPES IN GRAPHITE FROM L3 CHONDRITES: INDICATIONS FOR OXYGEN ISOTOPIC HETEROGENEITY. S. Mostefaoui1, FJ. Stadermann2, and A. El Goresy1. !Max-

    E-Print Network [OSTI]

    IN-SITU STUDY OF OXYGEN ISOTOPES IN GRAPHITE FROM L3 CHONDRITES: INDICATIONS FOR OXYGEN ISOTOPIC in-situ measurements of oxygen isotopes in graphite from the Khohar and Mez6-Madaras (L3) chondrites. Oxygen isotopic measurements were conducted with the Washington University ion microprobe (a modified

  3. Experimental studies of oxygen isotope fractionation in the carbonic acid system at 15, 25, and 40 (degrees)C 

    E-Print Network [OSTI]

    Beck, William Cory

    2004-11-15T23:59:59.000Z

    In light of recent studies that show oxygen isotope fractionation in carbonate minerals to be a function of HCO3 2-; and CO3 2- concentrations, the oxygen isotope fractionation and exchange between water and components ...

  4. Experimental studies of oxygen isotope fractionation in the carbonic acid system at 15, 25, and 40 (degrees)C

    E-Print Network [OSTI]

    Beck, William Cory

    2004-11-15T23:59:59.000Z

    In light of recent studies that show oxygen isotope fractionation in carbonate minerals to be a function of HCO3 2-; and CO3 2- concentrations, the oxygen isotope fractionation and exchange between water and components of the carbonic acid system...

  5. Fractionation of Oxygen Isotopes in Phosphate during its Interactions...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fractionation of Oxygen Isotopes in Phosphate during its Interactions with Iron Oxides. Fractionation of Oxygen Isotopes in Phosphate during its Interactions with Iron Oxides....

  6. Oxygen isotope fractionation in the vacuum ultraviolet photodissociation of carbon monoxide: Wavelength, pressure and temperature dependency.

    E-Print Network [OSTI]

    Chakraborty, Subrata

    2013-01-01T23:59:59.000Z

    Oxygen isotope fractionation in the vacuum ultravioletmeasurement of the associated oxygen isotopic composition ofwavelength dependency of the oxygen isotopic composition in

  7. Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From...

    Open Energy Info (EERE)

    Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone Drill Cores Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Oxygen...

  8. Geothermal reservoir temperatures estimated from the oxygen isotope...

    Open Energy Info (EERE)

    reservoir temperatures estimated from the oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes Jump to: navigation, search OpenEI...

  9. Geothermal Reservoir Temperatures Estimated from the Oxygen Isotope...

    Open Energy Info (EERE)

    Temperatures Estimated from the Oxygen Isotope Compositions of Dissolved Sulfate and Water from Hot Springs and Shallow Drillholes Jump to: navigation, search OpenEI Reference...

  10. Oxygen isotopic exchange: A useful tool for characterizing oxygen conducting oxides

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Oxygen isotopic exchange: A useful tool for characterizing oxygen conducting oxides Bassat J we obtain in both cases data concerning the oxygen diffusion in the bulk and the oxygen exchange with regards to the oxygen reduction reaction. Detailed experimental and analytical processes are given

  11. Oxygen isotope exchange between water and semiquinones

    SciTech Connect (OSTI)

    Stevenson, G.R.; Wang, Z.Y.; Reiter, R.C.; Peters, S.J.

    1988-09-14T23:59:59.000Z

    A reaction is described that can be utilized to produce /sup 17/O-labeled anion radicals that yield strong well resolved ESR signals exhibiting splitting from the /sup 17/O nucleus. The oxygen anthraquinone has been studied, and the results are reported herein. 7 references, 1 figure.

  12. The JET Hydrogen-Oxygen Recombination Sensor – A Safety Device for Hydrogen Isotope Processing Systems

    E-Print Network [OSTI]

    The JET Hydrogen-Oxygen Recombination Sensor – A Safety Device for Hydrogen Isotope Processing Systems

  13. The influence of kinetics on the oxygen isotope composition of calcium carbonate

    E-Print Network [OSTI]

    Watkins, Jim

    The influence of kinetics on the oxygen isotope composition of calcium carbonate James M. Watkins a and calcium carbonate. Although oxygen isotope separation is expected on theoretical grounds, the temperature on equilibrium fractionation of oxygen isotopes between calcium carbonate and water. Equili- brium oxygen isotope

  14. Triple Oxygen Isotope Measurement of Nitrate to Analyze Impact of Aircraft Emissions

    E-Print Network [OSTI]

    Chan, Sharleen

    P. ; Craig, H. Atmospheric oxygen: isotopic composition andM.H. 1986. A non-mass-dependent oxygen isotope effect in theof ozone from molecular oxygen: the role of symmetry in

  15. Oxygen isotopic ratios in intermediate-mass red giants

    E-Print Network [OSTI]

    Lebzelter, Thomas; Hinkle, Kenneth; Nowotny, Walter; Aringer, Bernhard

    2015-01-01T23:59:59.000Z

    Context. The abundances of the three main isotopes of oxygen are altered in the course of the CNO-cycle. When the first dredge-up mixes the burning products to the surface, the nucleosynthesis processes can be probed by measuring oxygen isotopic ratios. Aims. By measuring 16O/17O and 16O/18O in red giants of known mass we compare the isotope ratios with predictions from stellar and galactic evolution modelling. Methods. Oxygen isotopic ratios were derived from the K-band spectra of six red giants. The sample red giants are open cluster members with known masses of between 1.8 and 4.5 Msun . The abundance determination employs synthetic spectra calculated with the COMARCS code. The effect of uncertainties in the nuclear reaction rates, the mixing length, and of a change in the initial abundance of the oxygen isotopes was determined by a set of nucleosynthesis and mixing models using the FUNS code. Results. The observed 16O/17O ratios are in good agreement with the model results, even if the measured values do ...

  16. Oxygen isotopic disequilibrium in plagioclasecorundumhercynite xenoliths from the Voisey's Bay Intrusion, Labrador, Canada

    E-Print Network [OSTI]

    Oxygen isotopic disequilibrium in plagioclase­corundum­hercynite xenoliths from the Voisey's Bay to skeletal. Ion microprobe analyses indicate that oxygen isotopic equilibrium was neither established during corundum is characterized by 18 O values between 2.5 and 7.6. Oxygen isotopic equilibration with mantle

  17. Far Infrared Conductivity of Charge Density Wave Materials and the Oxygen Isotope Effect in High-T{sub c}

    E-Print Network [OSTI]

    Creager, W.N.

    2009-01-01T23:59:59.000Z

    determined. With 180 isotope enrichments of approximatelyand consistent 180 isotope enrichments of approximately 80%.enrichment, 0.90; the same group has reported oxygen isotope

  18. Hydrothermal flow systems in the Midcontinent Rift: Oxygen and hydrogen isotopic studies of the North Shore Volcanic Group and related hypabyssal sills, Minnesota

    SciTech Connect (OSTI)

    Park, Y.R.; Ripley, E.M. [Indiana Univ., Bloomington, IN (United States). Dept. of Geological Sciences] [Indiana Univ., Bloomington, IN (United States). Dept. of Geological Sciences

    1999-06-01T23:59:59.000Z

    Rift-related lavas of the North Shore Volcanic Group (NSVG) are intruded by plutonic rocks of the Duluth Complex along the unconformity between the NSVG and the underlying Proterozoic metasedimentary rocks (Animikie Group) and Archean volcano-sedimentary and plutonic rocks. Heat associated with the emplacement of the mafic intrusions generated fluid flow in the overlying plateau lavas. {delta}{sup 18}O values for whole rocks from the NSVG and hypabyssal sills range from 5.5 to 17.7{per_thousand} and 5.3 to 11.5{per_thousand}, respectively, and most values are higher than those considered normal for basaltic rocks (5.4 to 6.0{per_thousand}). In general, there is a positive correlation between whole rock {delta}{sup 18}O and water content, which suggests that elevated {delta}{sup 18}O values are related primarily to secondary mineral growth and isotopic exchange during hydrothermal alteration and metamorphism. {delta}{sup 18}O{sub H{sub 2}O} values computed from amygdule-filling minerals such as smectite, chlorite, and epidote found in low- to high-temperature metamorphic zones range from {approximately}{minus}1 to 6{per_thousand} with an average value of {approximately}3{per_thousand}. Smectite in the lower-grade zones gives computed {delta}D{sub H{sub 2}O} values between {minus}26 and {minus}83{per_thousand}, whereas epidote in the higher-grade zones gives {delta}D{sub H{sub 2}O} values of {minus}15 to 6{per_thousand}. Fluid isotopic compositions computed from epidote and smectite values are suggestive of the involvement of at least two fluids during the early stages of amygdule filling. Fluid {delta}D and {delta}{sup 18}O values determined from epidote at the higher metamorphic grades indicate that seawater dominated the deeper portions of the system where greenschist facies assemblages and elevated {delta}{sup 18}O values were produced in flow interiors, as well as margins. Smectite isotopic compositions suggest that meteoric water was predominant in the shallower portions of the system. The increase in {delta}{sup 18}O values of massive flow interiors with depth is interpreted as a result of rock interaction with a fluid of constant oxygen isotopic composition with increasing temperature. The stable isotopic data are supportive of previous suggestions that seawater was involved in the hydrothermal system associated with the Midcontinent Rift. Although the origin of the seawater remains problematic, it appears that marine incursions may have occurred during the late stages of Portage Lake volcanism, and periodically thereafter.

  19. Oxygen isotope composition of evapotranspiration and its relation to C4 photosynthetic discrimination

    E-Print Network [OSTI]

    Minnesota, University of

    the relation between canopy leaf water 18 O enrichment, 18 OCO2 photosynthetic discrimination (18 D), isotopeOxygen isotope composition of evapotranspiration and its relation to C4 photosynthetic; published 23 March 2011. [1] The oxygen isotope of water (18 OH2O) and carbon dioxide (18 OCO2

  20. Instructions for use Petrology, trace element abundances and oxygen isotopic1

    E-Print Network [OSTI]

    Tsunogai, Urumu

    Instructions for use #12;1 Petrology, trace element abundances and oxygen isotopic1 compositions@jamstec.go.jp15 16 17 #12;2 ABSTRACT1 We report the petrology, trace element abundances and oxygen isotopic and isotopic compositions as well as in their petrology.1 CAIs are composed of refractory minerals

  1. Oxygen isotope records of goethite from ferricrete deposits indicate regionally varying Holocene climate change in

    E-Print Network [OSTI]

    Hren, Michael

    Oxygen isotope records of goethite from ferricrete deposits indicate regionally varying Holocene isotopes of goethite from ferricrete deposits were measured from both northern and southern Rocky Mountain in oxygen isotope values of 14 C-dated goethites in the northern Rocky Mountains suggests a regional

  2. Stable isotope studies

    SciTech Connect (OSTI)

    Ishida, T.

    1992-01-01T23:59:59.000Z

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs.

  3. Oxygen Isotope Effects as Probes of Electron Transfer Mechanisms and Structures of

    E-Print Network [OSTI]

    Roth, Justine P.

    Oxygen Isotope Effects as Probes of Electron Transfer Mechanisms and Structures of Activated O2, Maryland 21218 RECEIVED ON JULY 26, 2008 C O N S P E C T U S Competitively determined oxygen (18 O) isotope effects can be power- ful probes of chemical and biological transformations involving molec- ular oxygen

  4. The bound coherent neutron scattering length of the oxygen isotopes

    SciTech Connect (OSTI)

    Fischer, Henry E [Institut Laue-Langevin (ILL); Simonson, J Michael {Mike} [ORNL; Neuefeind, Joerg C [ORNL; Lemmel, Hartmut [Technical University Vienna; Rauch, Helmut [E141 Atominstitut der Österreichischen Universitäten,; Zeidler, Anita [University of Bath; Salmon, Phil [University of Bath

    2012-01-01T23:59:59.000Z

    The technique of neutron interferometry was used to measure the bound coherent neutron scattering length bcoh of the oxygen isotopes 17O and 18O. From the measured difference in optical path between two water samples, either H2 17O or H2 18O versus H2 natO, where nat denotes the natural isotopic composition, we obtain bcoh , 17O = 5.867(4) fm and bcoh , 18O = 6.009(5) fm, based on the accurately known value of bcoh , natO = 5.805(4) fm which is equal to bcoh , 16O within the experimental uncertainty. Our results for bcoh , 17O and bcoh , 18O differ appreciably from the standard tabulated values of 5.6(5) fm and 5.84(7) fm, respectively. In particular, our measured scattering length contrast of 0.204(3) fm between 18O and natO is nearly a factor of 6 greater than the tabulated value, which renders feasible neutron diffraction experiments using 18O isotope substitution and thereby offers new possibilites for measuring the partial structure factors of oxygen-containing compounds, such as water.

  5. Calibration of sclerosponge oxygen isotope records to temperature using high-resolution d18

    E-Print Network [OSTI]

    Miami, University of

    Calibration of sclerosponge oxygen isotope records to temperature using high-resolution d18 O data; available online 21 May 2009 Abstract A revised calibration is presented relating the oxygen isotope an existing calibration which was determined using measurements of salinity rather than directly measured d18

  6. 15N2 formation and fast oxygen isotope exchange during pulsed...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    N2 formation and fast oxygen isotope exchange during pulsed 15N18O exposure of MnOxCeO2. 15N2 formation and fast oxygen isotope exchange during pulsed 15N18O exposure of MnOx...

  7. Holocene Paleohydrology and Paleoclimate at Treeline, North-Central Russia, Inferred from Oxygen Isotope

    E-Print Network [OSTI]

    Edwards, Thomas W.D.

    18 O from secondary evap- orative isotopic enrichment is aided by knowledge of the distribu- tion Isotope Records in Lake Sediment Cellulose Brent B. Wolfe, Thomas W. D. Edwards,1 and Ramon Aravena, 1998 Lake-water oxygen-isotope histories for three lakes in northern Russia, derived from the cellulose

  8. OXYGEN ISOTOPE MEASUREMENTS OF A RARE MURCHISON TYPE A CAI AND ITS RIM. J. E. P. , J. I. Simon2

    E-Print Network [OSTI]

    Grossman, Lawrence

    OXYGEN ISOTOPE MEASUREMENTS OF A RARE MURCHISON TYPE A CAI AND ITS RIM. J. E. P. Matzel1 , J. I-rich inclusions (CAIs) from CV chondrites commonly show oxygen isotope hetero- geneity among different mineral large and systematic variations in oxygen isotope composition within the margin and Wark-Lovering rim

  9. Oxygen isotope anomalies of the Sun and the original environment of the Solar system

    E-Print Network [OSTI]

    Jeong-Eun Lee; Edwin A. Bergin; James R. Lyons

    2008-03-15T23:59:59.000Z

    We present results from a model of oxygen isotopic anomaly production through selective photodissociation of CO within the collapsing proto-Solar cloud. Our model produces a proto-Sun with a wide range of Delta_17O values depending on the intensity of the ultraviolet radiation field. Dramatically different results from two recent Solar wind oxygen isotope measurements indicate that a variety of compositions remain possible for the solar oxygen isotope composition. However, constrained by other measurements from comets and meteorites, our models imply the birth of the Sun in a stellar cluster with an enhanced radiation field and are therefore consistent with a supernova source for 60Fe in meteorites.

  10. Oxygen isotope records of carboniferous seasonality on the Russian platform

    E-Print Network [OSTI]

    Wang, Huayu

    1998-01-01T23:59:59.000Z

    Seven isotopic and eight trace element (TE) profiles across shell growth lines are presented, based on over 1000 stable isotope and electron microprobe analyses on six brachiopod shells (Gigantoproductus), to quantify seasonal temperature change...

  11. Oxygen isotope heterogeneity and disequilibria of olivine crystals in large volume Holocene basalts from Iceland: Evidence

    E-Print Network [OSTI]

    Bindeman, Ilya N.

    and compositional zoning in selected grains, and subtle to severe D18 O (melt-olivine) and D18 O (plagioclase isotope laser fluorination analyses of 55 individual and bulk olivine crystals, coexisting individual different lavas, and variable core-to-rim oxygen isotopic zoning is present in selected olivine grains. Many

  12. Mechanistic studies using kinetic isotope effects

    E-Print Network [OSTI]

    Schulmeier, Brian E.

    1999-01-01T23:59:59.000Z

    Understanding reaction mechanisms is an important aspect of chemistry. A now convenient way to study reaction mechanisms is kinetic isotope effects at natural abundance. This technique circumvents the cumbersome methods of traditional isotope effect...

  13. Oxygen isotope content of CO2 in nocturnal ecosystem respiration: 1. Observations in forests along a precipitation transect in Oregon,

    E-Print Network [OSTI]

    Ehleringer, Jim

    in the vapor pressure deficit of air that caused isotopic enrichment of soil and leaf water. The enriched soil to evaporative enrichment overshadowed the original isotopic composition of precipitation as a first orderOxygen isotope content of CO2 in nocturnal ecosystem respiration: 1. Observations in forests along

  14. Electrochemical studies of quinone oxygen

    SciTech Connect (OSTI)

    Deanhardt, M.L. (Lander College, Greenwood, SC (US)); Mushrush, G.W.; Stalick, W.M. (Chemistry Dept., George mason Univ., Fairfax, VA (US)); Watkins, J.M. Jr. (Naval Research Lab., Fuels Section, Code 6180, Washington, DC (US))

    1990-02-01T23:59:59.000Z

    Asphaltenes are a chemically complex mixture of aromatic and heteroaromatic compounds. This material contains oxygen in various functional groups. The distribution includes esters, carboxylic acids, phenolic and most probably quinone type oxygen functionalities. The present work details the complete electrochemical behaviour of quinone type oxygen. The method is quinone specific. A condensed aromatic quinone, 9,10-anthraquinone, was selected as representative of complex quinones. By this method quinones can be determined in the presence of other oxygen functional groups, alcohols, carboxylic acids, ethers, and other carbonyls.

  15. Paleogene cooling (55-30 MA) as inferred from oxygen isotope variation within mollusc shells

    E-Print Network [OSTI]

    Kobashi, Takuro

    2001-01-01T23:59:59.000Z

    by the sudden appearance of a major continental glacier on Antarctica. We examine this cooling trend by analyzing oxygen isotope variation within mollusc shells from the Gulf Coastal Plain of the southern U.S. Our records show a secular cooling trend of mean...

  16. Pore water evolution in oilfield sandstones: constraints from oxygen isotope microanalyses of quartz cement

    E-Print Network [OSTI]

    Haszeldine, Stuart

    Pore water evolution in oilfield sandstones: constraints from oxygen isotope microanalyses to trace the origin and evolution of pore waters in three distinct reservoirs of the Brae Formation water evolution was reconstructed from the time of deposition of the sandstones in the Upper Jurassic

  17. Rare sulfur and triple oxygen isotope geochemistry of volcanogenic sulfate aerosols

    E-Print Network [OSTI]

    Bindeman, Ilya N.

    Rare sulfur and triple oxygen isotope geochemistry of volcanogenic sulfate aerosols I.N. Bindeman a of Technology, Pasadena, CA, USA c Department of Earth and Planetary Sciences, McGill University, Montreal, Que., Canada d Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland

  18. Age through tandem correlation of Quaternary relative paleointensity (RPI) and oxygen isotope data at IODP Site U1306 (Eirik Drift, SW

    E-Print Network [OSTI]

    Stoner, Joseph

    Age through tandem correlation of Quaternary relative paleointensity (RPI) and oxygen isotope data paleointensity Oxygen isotopes Deep Western Boundary Current a b s t r a c t Planktic oxygen isotope (d18 O) and relative paleointensity (RPI) data are used in tandem to generate an age model for the last 1 Myr from

  19. Oxygen isotope constraints on the origin of impact glasses from the cretaceous-tertiary boundary

    SciTech Connect (OSTI)

    Blum, J.D.; Chamberlain, C.P. (Dartmouth Coll, Hanover, NH (United States))

    1992-08-21T23:59:59.000Z

    Laser-extraction oxygen isotope and major element analyses of individual glass spherules from Haitian Cretaceous-Tertiary boundary sediments demonstrate that the glasses fall on a mixing line between an isotopically heavy ({delta}{sup 18}O = 14 per mil) high-calcium composition and an isotopically light ({delta}{sup 18}O = 6 per mil) high-silicon composition. This trend can be explained by melting of heterogeneous source rocks during the impact of an asteroid (or comet) {approximately}65 million years ago. The data indicate that the glasses are a mixture of carbonate and silicate rocks and exclude derivation of the glasses either by volcanic processes or as mixtures of sulfate-high evaporate and silicate rocks.

  20. Searching for isovector signatures in the neutron-rich oxygen and calcium isotopes

    E-Print Network [OSTI]

    Wei-Chia Chen; J. Piekarewicz

    2015-03-10T23:59:59.000Z

    We search for potential isovector signatures in the neutron-rich oxygen and calcium isotopes within the framework of a relativistic mean-field theory with an exact treatment of pairing correlations. To probe the isovector sector we calibrate a few relativistic density functionals using the same isoscalar constraints but with one differing isovector assumption. It is found that under certain conditions, the isotopic chain in oxygen can be made to terminate at the experimentally observed ${}^{24}$O isotope and in the case of the calcium isotopes at ${}^{60}$Ca. To produce such behavior, the resulting symmetry energy must be soft, with predicted values for the symmetry energy and its slope at saturation density being $J\\!=\\!(30.92\\pm0.47)$ MeV and $L\\!=\\!(51.0\\pm1.5)$ MeV, respectively. As a consequence, the neutron-skin thickness of ${}^{208}$Pb is rather small: $R_{\\rm skin}^{208}\\!=\\!(0.161\\pm0.011)$ fm. This same model - labelled "FSUGarnet" - predicts $R_{1.4}\\!=\\!(13.1\\pm0.1)$ km for the radius of a "canonical" 1.4$M_{\\odot}$ neutron star, yet is also able to support a two-solar-mass neutron star.

  1. Chiral three-nucleon forces and the evolution of correlations along the oxygen isotopic chain

    E-Print Network [OSTI]

    A. Cipollone; C. Barbieri; P. Navrátil

    2014-12-01T23:59:59.000Z

    The impact of three-nucleon forces (3NFs) along the oxygen chain is investigated for the spectral distribution for attachment and removal of a nucleon, spectroscopic factors and matter radii. We employ self-consistent Green's function (SCGF) theory which allows a comprehensive calculation of the single particle spectral function. For the closed subshell isotopes, $^{14}$O, $^{16}$O, $^{22}$O, $^{24}$O and $^{28}$O, we perform calculations with the Dyson-ADC(3) method. The remaining open shell isotopes are studied using the newly developed Gorkov-SCGF formalism up to second order. We produce plots for the full-fledged spectral distributions. The spectroscopic factors for the dominant quasiparticle peaks are found to depend very little on the leading order (NNLO) chiral 3NFs. The latters have small impact on the calculated matter radii, which, however are consistently obtained smaller than experiment. Similarly, single particle spectra tend to be diluted with respect to experiment. This effect might hinder, to some extent, the onset of correlations and screen the quenching of calculated spectroscopic factors. The most important effects of 3NFs is thus the fine tuning of the energies for the dominant quasiparticle states, which govern the shell evolution and the position of driplines. Although present chiral NNLO 3NFs interactions do reproduce the binding energies correctly in this mass region, the details of the nuclear wave function remain at odd with the experiment showing too small radii and a too dilute single particle spectrum, similar to what already pointed out for larger masses. This suggests a lack of repulsion in the present model of NN+3N interactions which is mildly apparent already for masses in the A=14--28 range.

  2. Oxygen and Carbon Isotopes and Coral Growth in the Gulf of Mexico and Caribbean Sea as Environmental and Climate Indicators

    E-Print Network [OSTI]

    Wagner, Amy Jo

    2011-02-22T23:59:59.000Z

    thanks goes to the crew of the M/V Fling; the Flower Garden Banks National Marine Sanctuary (FGBNMS) staff, E. Hickerson, G.P. Schmal, L. Kurjelja; the Florida Keys National Marine Sanctuary staff, J. Halas, B. Causey, A. Massey; U.S. Geological Survey... OXYGEN AND CARBON ISOTOPES AND CORAL GROWTH IN THE GULF OF MEXICO AND CARIBBEAN SEA AS ENVIRONMENTAL AND CLIMATE INDICATORS A Dissertation by AMY JO WAGNER Submitted to the Office of Graduate Studies of Texas A&M University...

  3. Transferring oxygen isotopes to 1,2,4-benzotriazine 1-oxides forming the corresponding 1,4-dioxides by using the HOF$CH3CN complex

    E-Print Network [OSTI]

    Gates, Kent. S.

    Transferring oxygen isotopes to 1,2,4-benzotriazine 1-oxides forming the corresponding 1,4-dioxides Available online 14 August 2012 Keywords: Oxygen transfer 18 O isotope Tirapazamine HOF$CH3CN F2/N2 N is their ability to capitalize on the low oxygen (hypoxic) environment found in many solid tumors. The lead

  4. HETEROGENEOUS OXYGEN ISOTOPIC COMPOSITION OF A COMPLEX WARK-LOVERING RIM AND THE MARGIN OF A REFRACTORY INCLUSION FROM LEOVILLE. J. I. Simon1

    E-Print Network [OSTI]

    Grossman, Lawrence

    HETEROGENEOUS OXYGEN ISOTOPIC COMPOSITION OF A COMPLEX WARK-LOVERING RIM AND THE MARGIN inclusion interiors. Extreme oxygen isotopic heterogeneity measured in CAIs has been explained by mixing between distinct oxygen gas reservoirs in the nebula [13]. Some WL rims contain relatively simple mineral

  5. Theoretical Study of the Structure, Stability and Oxygen Reduction...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Study of the Structure, Stability and Oxygen Reduction Activity ofUltrathin Platinum Nanowires. Theoretical Study of the Structure, Stability and Oxygen Reduction Activity...

  6. Density Functional Study of the Structure, Stability and Oxygen...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Study of the Structure, Stability and Oxygen Reduction Activity of Ultrathin Platinum Nanowires. Density Functional Study of the Structure, Stability and Oxygen Reduction Activity...

  7. Oxygen Transport Studies in Nanocrystalline Ceria Films. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Transport Studies in Nanocrystalline Ceria Films. Oxygen Transport Studies in Nanocrystalline Ceria Films. Abstract: Oxygen uptake and conductivity were measured by nuclear...

  8. Density Functional Theory Study of Oxygen Reduction Activity...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Density Functional Theory Study of Oxygen Reduction Activity on Ultrathin Platinum Nanotubes. Density Functional Theory Study of Oxygen Reduction Activity on Ultrathin Platinum...

  9. CAN GALACTIC CHEMICAL EVOLUTION EXPLAIN THE OXYGEN ISOTOPIC VARIATIONS IN THE SOLAR SYSTEM?

    SciTech Connect (OSTI)

    Lugaro, Maria [Monash Centre for Astrophysics (MoCA), Building 28, Monash University, Clayton, VIC 3800 (Australia); Liffman, Kurt [CSIRO/MSE, P.O. Box 56, Highett, VIC 3190 (Australia); Ireland, Trevor R. [Planetary Science Institute and Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Maddison, Sarah T., E-mail: maria.lugaro@monash.edu [Centre for Astrophysics and Supercomputing, Swinburne University, H39, P.O. Box 218, Hawthorn, VIC 3122 (Australia)

    2012-11-01T23:59:59.000Z

    A number of objects in primitive meteorites have oxygen isotopic compositions that place them on a distinct, mass-independent fractionation line with a slope of one on a three-isotope plot. The most popular model for describing how this fractionation arose assumes that CO self-shielding produced {sup 16}O-rich CO and {sup 16}O-poor H{sub 2}O, where the H{sub 2}O subsequently combined with interstellar dust to form relatively {sup 16}O-poor solids within the solar nebula. Another model for creating the different reservoirs of {sup 16}O-rich gas and {sup 16}O-poor solids suggests that these reservoirs were produced by Galactic chemical evolution (GCE) if the solar system dust component was somewhat younger than the gas component and both components were lying on the line of slope one in the O three-isotope plot. We argue that GCE is not the cause of mass-independent fractionation of the oxygen isotopes in the solar system. The GCE scenario is in contradiction with observations of the {sup 18}O/{sup 17}O ratios in nearby molecular clouds and young stellar objects. It is very unlikely for GCE to produce a line of slope one when considering the effect of incomplete mixing of stellar ejecta in the interstellar medium. Furthermore, the assumption that the solar system dust was younger than the gas requires unusual timescales or the existence of an important stardust component that is not theoretically expected to occur nor has been identified to date.

  10. Oxygen isotope content of CO2 in nocturnal ecosystem respiration: 2. Short-term dynamics of foliar and soil component fluxes in an

    E-Print Network [OSTI]

    Ehleringer, Jim

    Oxygen isotope content of CO2 in nocturnal ecosystem respiration: 2. Short-term dynamics of foliar; accepted 29 October 2003; published 23 December 2003. [1] The oxygen isotope contents (d18 O) of soil showed enrichment over a 2-week sampling period as the weather became hot and dry (leaves 0.9 to 15

  11. doi:10.1016/j.gca.2005.04.017 A model for oxygen and sulfur isotope fractionation in sulfate during bacterial sulfate

    E-Print Network [OSTI]

    Gilli, Adrian

    describing the fraction- ation relationship between the sulfur and the oxygen isotope composition of residual sulfate ( 34 SSO4_residual, 18 OSO4_residual) and the amount of residual sulfate. The model is based exclusively on oxygen isotope exchange between cell-internal sulfur compounds and ambient water

  12. Enriched Background Isotope Study (EBIS) Litter reciprocal transplant studies to understand sources, transport and

    E-Print Network [OSTI]

    1 Enriched Background Isotope Study (EBIS) Litter reciprocal transplant studies to understand were removed from this archived version.] #12;3 Enriched Background Isotope Study (EBIS): Litter

  13. Oxygen isotope fractionation in the vacuum ultraviolet photodissociation of carbon monoxide: Wavelength, pressure and temperature dependency.

    E-Print Network [OSTI]

    Chakraborty, Subrata

    2013-01-01T23:59:59.000Z

    The extent of heavy isotope enrichment (? 17 O and ? 18 O)range of the heavy isotope enrichment (? 17 O and ? 18 O) isThe extent of heavy isotope enrichment (? 17 O and ? 18 O)

  14. Oxygen reduction on platinum : an EIS study

    E-Print Network [OSTI]

    Golfinopoulos, Theodore

    2009-01-01T23:59:59.000Z

    The oxygen reduction reaction (ORR) on platinum over yttria-stabilized zirconia (YSZ) is examined via electrochemical impedance spectroscopy (EIS) for oxygen partial pressures between 10-4 and 1 atm and at temperatures ...

  15. ISOTOPES

    E-Print Network [OSTI]

    Lederer, C. Michael

    2013-01-01T23:59:59.000Z

    rare (0.017%) isotope 36s at enrichments of 70% at a price32). The enrichment of carbon isotopes by C02-carbamatesulfur isotopes by S02-NaHS03 exchange and the enrichment of

  16. Seasonal radiocarbon and oxygen isotopes in a Galapagos coral: Calibration with climate indices

    E-Print Network [OSTI]

    Druffel, Ellen R. M; Griffin, Sheila; Glynn, Danielle S; Dunbar, Robert B; Mucciarone, David A; Toggweiler, J. Robert

    2014-01-01T23:59:59.000Z

    stable isotopes in Palmyra corals during the past century,radiocarbon content of corals from the Galapagos Islands,1981), Radiocarbon in annual coral rings from the eastern

  17. Oxygen Enriched Combustion System Performance Study 

    E-Print Network [OSTI]

    Chen, S. L.; Kwan, Y.; Abele, A. R.; Silver, L. S.; Kobayashi, H.

    1987-01-01T23:59:59.000Z

    , and then to verify the performance of selected systems in research furnaces. Tests of several commercial burner designs have been conducted at scales of 1 x 10^6 Btu/hr and 10 x 10^6 Btu/hr. The burners represent both conventional air fired designs and oxygen...

  18. An Oxygen Isotope Study Of Hydrothermal Alteration In The Lake...

    Open Energy Info (EERE)

    the highly fractured Eureka Graben, southwest of the caldera, was probably the principal source of recharge groundwater for the Lake City system. (2) Fluid flow within the caldera...

  19. DME-to-oxygenates process studies

    SciTech Connect (OSTI)

    Tartamella, T.L.; Sardesai, A.; Lee, S. [Univ. of Akron, OH (United States); Kulik, C.J. [Electric Power Research Inst., Palo Alto, CA (United States)

    1994-12-31T23:59:59.000Z

    The feasibility of the production of hydrocarbons from dimethyl ether (DNM) has been illustrated in a fixed bed micro-reactor as well as a bench scale fluidized bed reactor by the University of Akron/EPRI DME-to-Hydrocarbon (DTG) Process. The DTG process has distinct advantages over its methanol based counterpart. Specifically, the DTG process excels in the area of higher productivity, higher per-pass conversion, and lower heat duties than the MTG process. Also of special importance is the production of oxygenates -- including MTBE, ETBE, and TAME. DME may be reacted with isobutylene to produce a mixture of MTBE and ETBE. The properties of ETBE excel over MTBE in the areas of lower RVP and higher RON. According to industrial reports, MTBE is the fastest growing chemical (1992 US capacity 135,350 BPD, with expected growth of 34%/year to 1997). Also, recent renewed interest as an octane-enhancer and as a source of oxygen has spurred a growing interest in nonrefinery synthesis routes to ETBE. TAME, with its lower RVP and higher RON has proven useful as a gasoline blending agent and octane enhancer and may also be produced directly from DME. DME, therefore, serves as a valuable feedstock in the conversion of may oxygenates with wide-scale industrial importance. It should be also noted that the interest in the utilization of DME as process feedstock is based on the favorable process economics of EPRI/UA`s liquid phase DME process.

  20. Isotopic dilution and solvent effect studies using raman difference spectroscopy

    E-Print Network [OSTI]

    Johnson, Andrew Norman

    1984-01-01T23:59:59.000Z

    ISOTOPIC DILUTION AND SOLVENT EFFECT STUDIES USING RAMAN DIFFERENCE SPECTROSCOPY A Thesis by ANDREW NORMAN JOHNSON Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE August 1984 Major Subject: Chemistry ISOTOPIC DILUTION AND SOLVENT EFFECT STUDIES USING RAMAN DIFFERENCE SPECTROSCOPY A Thesis by ANDREW NORMAN JOHNSON Approved as to style and content by: Jaan Laane (Chairman of Committee) J. . Bevan...

  1. 15N2 formation and fast oxygen isotope exchange during pulsed 15N18O exposure of MnOx/CeO2

    SciTech Connect (OSTI)

    Kwak, Ja Hun; Szanyi, Janos

    2014-12-23T23:59:59.000Z

    Pulsing 15N18O onto an annealed 1% Mn16Ox/Ce16O2 catalyst resulted in very fast oxygen isotope exchange and 15N2 formation at 295 K. In the 1st 15N18O pulse, due to the presence of large number of surface oxygen defects, extensive 15N218O and 15N2 formations were observed. In subsequent pulses oxygen isotope exchange dominated as a result of highly labile oxygen in the oxide. We gratefully acknowledge the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy/Vehicle Technologies Program for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.

  2. Solid phases of spatially nanoconfined oxygen: A neutron scattering study

    SciTech Connect (OSTI)

    Kojda, Danny [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 14109 Berlin (Germany) [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 14109 Berlin (Germany); Freie Universität Berlin, 14195 Berlin (Germany); Wallacher, Dirk; Hofmann, Tommy, E-mail: tommy.hofmann@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 14109 Berlin (Germany)] [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 14109 Berlin (Germany); Baudoin, Simon; Hansen, Thomas [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France)] [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Huber, Patrick [Technische Universität Hamburg-Harburg, 21073 Hamburg (Germany)] [Technische Universität Hamburg-Harburg, 21073 Hamburg (Germany)

    2014-01-14T23:59:59.000Z

    We present a comprehensive neutron scattering study on solid oxygen spatially confined in 12 nm wide alumina nanochannels. Elastic scattering experiments reveal a structural phase sequence known from bulk oxygen. With decreasing temperature cubic ?-, orthorhombic ?- and monoclinic ?-phases are unambiguously identified in confinement. Weak antiferromagnetic ordering is observed in the confined monoclinic ?-phase. Rocking scans reveal that oxygen nanocrystals inside the tubular channels do not form an isotropic powder. Rather, they exhibit preferred orientations depending on thermal history and the very mechanisms, which guide the structural transitions.

  3. Large-amplitude Qn-Qp collectivity in the neutron-rich oxygen isotope 20O

    E-Print Network [OSTI]

    A. P. Severyukhin; M. Bender; H. Flocard; P. -H. Heenen

    2007-01-12T23:59:59.000Z

    By means of HFB calculations with independent constraints on axial neutron and proton quadrupole moments Q_n and Q_p, we investigate the large amplitude isoscalar and isovector deformation properties of the neutron-rich isotope 20O. Using the particle-number and angular-momentum projected Generator Coordinate Method, we analyze the collective dynamics in the {Q_n, Q_p} plane. The parameterization SLy4 of the Skyrme interaction is used for all calculations in connection with a density-dependent zero-range pairing interaction. Our results show that already for this moderately neutron-rich nucleus the transition moments are modified when independent neutron and proton collective dynamics are allowed.

  4. Isotopes

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12 Investigation Peer ReviewIronNuclear Physics » Isotopes

  5. Intramolecular Isotope Effects for the Study of Reactions with MassTransfer Limitations

    E-Print Network [OSTI]

    Wagner, Joshua G.

    2010-01-16T23:59:59.000Z

    The research presented provides a method to use the comparison of intermolecular isotope effects vs. the intramolecular isotope effects for the study of reactions in which study of the rate limiting step is ambiguous due to interfering mass transfer...

  6. avec oxygenation modelisation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Experimental calibration of oxygen isotope fractionation between quartz and zircon Dustin Trail a the results of an experimental calibration of oxygen isotope fractionation...

  7. A method of determining the dissolved oxygen in the moisture of a porous medium and some oxygen diffusion studies

    E-Print Network [OSTI]

    Runkles, Jack Ralph

    1952-01-01T23:59:59.000Z

    this dissolved oxygen The sample chamber apparatus gives ocnsplcte seal of the bottle from the atmosphere The ohsabor does not require a large ameunt Of nitrogen Sb remove all the oxygen from it, It is easily portable and light in weight The proposed method... METHOD QF DETRHRIUIHO THE DISSOLVED OXmEK IE THE MOISTURE OF A POROUS ERDD% @AD SMfE QXYOEB DKFFUSIOE STUDIES ' INTRO DUO fQRF, I Oxygen, bas been known to be important in plant growth fox maay years There has been a great deal of xesearoh...

  8. Oxygen Modulation via Microfluidic Devices Oxygen is a key but under-studied metabolic variable. It influences biological phenomena as diverse as

    E-Print Network [OSTI]

    Ben-Arie, Jezekiel

    Oxygen Modulation via Microfluidic Devices Oxygen is a key but under-studied metabolic variable methods to modulate oxygen are crude and inefficient. Our lab has developed a suite of devices which can rapidly alter oxygen conditions surrounding cells in both position and time.[1-3]. Moreover, because

  9. Lead isotope study of the late Archean Lac des Iles palladium deposit, Canada: enrichment of platinum

    E-Print Network [OSTI]

    ARTICLE Lead isotope study of the late Archean Lac des Iles palladium deposit, Canada: enrichment Lead isotopic compositions of mineral separates are presented from the mineralized zones (Roby Province of Canada. Plagioclase separates show Pb isotope ratios similar to those of the late Archean

  10. Fusion of neutron rich oxygen isotopes in the crust of accreting neutron stars

    E-Print Network [OSTI]

    Horowitz, C J; Berry, D K

    2007-01-01T23:59:59.000Z

    Fusion reactions in the crust of an accreting neutron star are an important source of heat, and the depth at which these reactions occur is important for determining the temperature profile of the star. Fusion reactions depend strongly on the nuclear charge $Z$. Nuclei with $Z\\le 6$ can fuse at low densities in a liquid ocean. However, nuclei with $Z=8$ or 10 may not burn until higher densities where the crust is solid and electron capture has made the nuclei neutron rich. We calculate the $S$ factor for fusion reactions of neutron rich nuclei including $^{24}$O + $^{24}$O and $^{28}$Ne + $^{28}$Ne. We use a simple barrier penetration model. The $S$ factor could be further enhanced by dynamical effects involving the neutron rich skin. This possible enhancement in $S$ should be studied in the laboratory with neutron rich radioactive beams. We model the structure of the crust with molecular dynamics simulations. We find that the crust of accreting neutron stars may contain micro-crystals or regions of phase sep...

  11. Fusion of neutron rich oxygen isotopes in the crust of accreting neutron stars

    E-Print Network [OSTI]

    C. J. Horowitz; H. Dussan; D. K. Berry

    2008-04-07T23:59:59.000Z

    Fusion reactions in the crust of an accreting neutron star are an important source of heat, and the depth at which these reactions occur is important for determining the temperature profile of the star. Fusion reactions depend strongly on the nuclear charge $Z$. Nuclei with $Z\\le 6$ can fuse at low densities in a liquid ocean. However, nuclei with Z=8 or 10 may not burn until higher densities where the crust is solid and electron capture has made the nuclei neutron rich. We calculate the $S$ factor for fusion reactions of neutron rich nuclei including $^{24}$O + $^{24}$O and $^{28}$Ne + $^{28}$Ne. We use a simple barrier penetration model. The $S$ factor could be further enhanced by dynamical effects involving the neutron rich skin. This possible enhancement in $S$ should be studied in the laboratory with neutron rich radioactive beams. We model the structure of the crust with molecular dynamics simulations. We find that the crust of accreting neutron stars may contain micro-crystals or regions of phase separation. Nevertheless, the screening factors that we determine for the enhancement of the rate of thermonuclear reactions are insensitive to these features. Finally, we calculate the rate of thermonuclear $^{24}$O + $^{24}$O fusion and find that $^{24}$O should burn at densities near $10^{11}$ g/cm$^3$. The energy released from this and similar reactions may be important for the temperature profile of the star.

  12. The Kinetics of Dissociations of Aluminum - Oxygen Bonds in Aqueous Complexes - An NMR Study

    SciTech Connect (OSTI)

    Dr. William Casey

    2003-09-03T23:59:59.000Z

    OAK B262 The Kinetics of Dissociations of Aluminum--Oxygen Bonds in Aqueous Complexes--An NMR Study. In this project we determined rates and mechanisms of Al(III)-O bond rupture at mineral surfaces and in dissolved aluminum complexes. We then compared the experimental results to simulations in an attempt to predict rate coefficients. Most of the low-temperature reactions that are geochemically important involve a bonded atom or molecule that is replaced with another. We probe these reactions at the most fundamental level in order to establish a model to predict rates for the wide range of reactions that cannot be experimentally studied. The chemistry of small aluminum cluster (Figure) provides a window into the hydrolytic processes that control rates of mineral formation and the transformation of adsorbates into extended structures. The molecule shown below as an example exposes several types of oxygens to the bulk solution including seven structurally distinct sets of bridging hydroxyls. This molecule is a rich model for the aqueous interface of aluminum (hydr)oxide minerals, since it approaches colloidal dimensions in size, yet is a dissolved complex with +18 charge. We have conducted both {sup 17}O- {sup 27}Al- and {sup 19}F-NMR experiments to identify the reactive sites and to determine the rates of isotopic exchange between these sites and the bulk solution. The research was enormously successful and led to a series of papers that are being used as touchstones for assessing the accuracy of computer models of bond ruptures in water.

  13. Light stable isotope study of the Roosevelt Hot Springs thermal area, Southwestern Utah

    SciTech Connect (OSTI)

    Rohrs D.T.; Bowman, J.R.

    1980-05-01T23:59:59.000Z

    The isotopic composition of hydrogen, oxygen, and carbon has been determined for regional cold springs, thermal fluids, and rocks and minerals from the Roosevelt Hot Springs thermal area. The geothermal system has developed within plutonic granitic rocks and amphibolite facies gneiss, relying upon fracture-controlled permeability for the migration of the thermal fluids. Probably originating as meteoric waters in the upper elevations of the Mineral Mountains, the thermal waters sampled in the production wells display an oxygen isotopic shift of at least +1.2. Depletions of delta /sup 18/O in wole rock, K-feldspar, and biotite have a positive correlation with alteration intensity. W/R mass ratios, calculated from the isotopic shifts of rock and water, range up to 3.0 in a producing horizon of one well, although the K-feldspar has experienced only 30% exchange with the thermal waters. While veinlet quartz has equilibrated with the thermal waters, the /sup 18/O values of K-mica clay, an alteration product of plagioclase, mimic the isotopic composition of K-feldspar and whole rock. This suggests that locally small W/R ratios enable plagioclase to influence its alteration products by isotopic exchange.

  14. Task Technical Plan for Studies of Oxygen Consumption in the Catalyzed Hydrolysis of Tetraphenylborate Ion

    SciTech Connect (OSTI)

    Fink, S.D. [Westinghouse Savannah River Company, AIKEN, SC (United States)

    1996-12-20T23:59:59.000Z

    This document presents the plan for studies of how dissolved oxygen affects the catalytic decomposition of the tetraphenylborate ion in alkaline aqueous solution.

  15. Heavy-atom isotope effects on the acid-catalyzed hydrolysis of methyl benzoate

    SciTech Connect (OSTI)

    Marlier, J.F.; O'Leary, M.H.

    1981-05-08T23:59:59.000Z

    Results of the use of a previously reported technique of four-heavy atom isotope effects for study of the acid-catalyzed hydrolysis of methyl benzoate are reported. Ether oxygen and methyl carbon isotope effects on the reaction were measured by the usual natural-abundance isotope-ratio technique. The carbonyl oxygen isotope effect was measured by the pseudo-natural-abundance double-label method as was the carbonyl carbon isotope effect. The results led to the assumption that the hydrolysis of methyl benzoate proceeds by way of a tetrahedral intermediate. The small amount of oxygen exchange with the solvent that accompanies the hydrolysis indicated that it is intermediate formation rather than decomposition that is rate determining. The small magnitude of the observed carbon isotope effect on the acid-catalyzed hydrolysis of methyl benzoate compared to carbon isotope effects on other reactions of this compound indicate that the transition state is relatively reactant-like. (BLM)

  16. Experimental studies of the transfer phenomena of tritium in an isotope exchange column for recovery tritium

    E-Print Network [OSTI]

    Experimental studies of the transfer phenomena of tritium in an isotope exchange column for recovery tritium Anisia Bornea, Ion Cristescu, Marius Zamfirache, Carmen Varlam National Institute of R processes for tritium separation, is the catalyst isotope exchange water-hydrogen. The main problem

  17. Isotopic studies of the environmental chemistry of lead 

    E-Print Network [OSTI]

    Sugden, Carol Louise

    Lead emitted into the environment, primarily from the combustion of leaded petrol and industrial activities, such as metal smelting and coal burning, retains the isotopic signature of the ores from which it is derived. Accordingly, it is possible...

  18. Feasibility study of medical isotope production at Sandia National Laboratories

    SciTech Connect (OSTI)

    Massey, C.D.; Miller, D.L.; Carson, S.D. [Sandia National Labs., Albuquerque, NM (United States). Environmental Regulatory Assessment Dept.] [and others

    1995-12-01T23:59:59.000Z

    In late 1994, Sandia National Laboratories in Albuquerque, New Mexico, (SNL/NM), was instructed by the Department of Energy (DOE) Isotope Production and Distribution Program (IPDP) to examine the feasibility of producing medically useful radioisotopes using the Annular Core Research Reactor (ACRR) and the Hot Cell Facility (HCF). Los Alamos National Laboratory (LANL) would be expected to supply the targets to be irradiated in the ACRR. The intent of DOE would be to provide a capability to satisfy the North American health care system demand for {sup 99}Mo, the parent of {sup 99m}Tc, in the event of an interruption in the current Canadian supply. {sup 99m}Tc is used in 70 to 80% of all nuclear medicine procedures in the US. The goal of the SNL/NM study effort is to determine the physical plant capability, infrastructure, and staffing necessary to meet the North American need for {sup 99}Mo and to identify and examine all issues with potential for environmental impact.

  19. Quantification and propagation of errors when converting vertebrate biomineral oxygen isotope data to temperature for palaeoclimate reconstruction

    E-Print Network [OSTI]

    Pryor, Alexander J. E.; Stevens, Rhiannon E.; O’Connell, Tamsin C.; Lister, John R.

    2014-07-18T23:59:59.000Z

    interglacial-glacial cycle contexts at the Hallera Avenue site, Wroc?aw (Poland) (3 measurements ranging between 13.4‰ and 14.1‰; Skrzypek et al., 2011, Supplementary Data). The isotopic data were interpreted as indicating temperatures 2–4ºC higher than... using ?18Oprecipitation data from local or regional International Atomic Energy Agency monitoring stations that may not include (or be restricted to) data from the years when the analysed fauna were alive, rather than being estimated from water sources...

  20. JOIJKUAL I)E I'HYSIQUE Diffusion study of oxygen implanted in nickel oxide

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    JOIJKUAL I)E I'HYSIQUE Diffusion study of oxygen implanted in nickel oxide M. Meyer, S. Barbezat, C coefficients d'autodiffusion de I'oxygene dans l'oxyde de nickel, mesurkes rkemment, par Cchange isotopique implanted in nickel oxide; the experiments are carried out by annealing between 1 300 and 1 500 OC nickel

  1. Isotope shift and hyperfine structure studies of the krypton ion and the thallium atom

    E-Print Network [OSTI]

    Li, Yingfeng

    1991-01-01T23:59:59.000Z

    ISOTOPE SHIFT AND HYPERFINE STRUCTURE STUDIES OF THE KRYPTON ION AND THE THALLIUM ATOM A Thesis by YINGFENG LI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree...) Lewis A. Ford (Member) Christian P. Burger (Member) Richard L. Arnowitt (Head of Department) August 1991 777 ABSTRACT Isotope Shift and Hyperfine Structure Studies of the Krypton Ion and the Thallium Atom. tAugust 1991) Yingfeng Li, B. S...

  2. Delayed neutron studies of separated isotopes of Br, Rb, I, and Cs

    E-Print Network [OSTI]

    Reeder, R L; Wright, J F

    1976-01-01T23:59:59.000Z

    Discusses delayed neutron studies of separated isotopes of Br, Rb, I, and Cs are currently in progress at the Spectrometer for On-Line Analysis of Radionuclides (SOLAR) facility operated by Battelle, Pacific Northwest Laboratories. (2 refs).

  3. High flux isotope reactor cold source preconceptual design study report

    SciTech Connect (OSTI)

    Selby, D.L.; Bucholz, J.A.; Burnette, S.E. [and others

    1995-12-01T23:59:59.000Z

    In February 1995, the deputy director of Oak Ridge National Laboratory (ORNL) formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced Neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. The anticipated cold source will consist of a cryogenic LH{sub 2} moderator plug, a cryogenic pump system, a refrigerator that uses helium gas as a refrigerant, a heat exchanger to interface the refrigerant with the hydrogen loop, liquid hydrogen transfer lines, a gas handling system that includes vacuum lines, and an instrumentation and control system to provide constant system status monitoring and to maintain system stability. The scope of this project includes the development, design, safety analysis, procurement/fabrication, testing, and installation of all of the components necessary to produce a working cold source within an existing HFIR beam tube. This project will also include those activities necessary to transport the cold neutron beam to the front face of the present HFIR beam room. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and research and development (R and D), (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the preconceptual phase and establishes the concept feasibility. The information presented includes the project scope, the preliminary design requirements, the preliminary cost and schedule, the preliminary performance data, and an outline of the various plans for completing the project.

  4. Hydrogen and oxygen isotope variations in the high Himalaya peraluminous Manaslu leucogranite: evidence for heterogeneous sedimentary source

    SciTech Connect (OSTI)

    France-Lanord, C.; Sheppard, S.M.F.; Le Fort, P.

    1988-02-01T23:59:59.000Z

    The Manaslu granite belongs to the High Himalaya leucogranitic belt which was produced by melting of the crust during postcollisional thrusting. deltaD and delta/sup 18/O values have been determined for whole rock and coexisting minerals from the approx. 8 km thick Manaslu massif and its 50 km long dyke sheet, its country rocks and the Formation 1 (F1) paragneisses which are the source of the granite. From the distribution of deltaD values in the granite and its country rocks, circulation of very low deuterium meteoric hydrothermal waters was extremely localized. Because these waters are depleted in deuterium by up to 50% relative to modern meteoric waters, the Manaslu area was either at an altitude substantially higher than that of today or a mountain chain once existed to the south. The F1 gneisses have delta/sup 18/O/sub quartz/ between 12 and 14.3 per thousand which confirms that the granite was generated from F1, but deltaD values are approx. = 20 per thousand higher than in the granite. Infiltration of low deltaD fluid (approx. =-90 per thousand) into the hot but dry F1 probably triggered partial melting; these fluids could have come from the dehydration of the Midlands sediments which are separated from the overlying F1 by the Main Central Thrust. The correlations among delta/sup 18/O, (/sup 87/Sr/sup 86/Sr)/sub 20 Ma/ and epsilon Nd values in both F1 and the granite indicate that the variations of these isotopic ratios in the Manaslu are inherited from those in F1 at the time of melting. In turn, these ratios in F1 are related to the proportion of quartz and phyllosilicates for the isotopic ratios of Nd and O, and to the quantity of radiogenic Sr generated within the sediment, which is a function of age and Rb content. Some other Himalayan leucogranites require either other crustal source rocks of the delta/sup 18/O and /sup 87/Sr/sup 86/Sr ratios to F1 vary along the Himalaya.

  5. Effective interactions and shell model studies of heavy tin isotopes

    E-Print Network [OSTI]

    M. P. Kartamyshev; T. Engeland; M. Hjorth-Jensen; E. Osnes

    2006-10-05T23:59:59.000Z

    We present results from large-scale shell-model calculations of even and odd tin isotopes from 134Sn to 142}Sn with a shell-model space defined by the 1f7/2,2p3/2,0h9/2,2p1/2,1f5/2,0i13/2 single-particle orbits. An effective two-body interaction based on modern nucleon-nucleon interactions is employed. The shell-model results are in turn analyzed for their pairing content using a generalized seniority approach. Our results indicate that a pairing-model picture captures a great deal of the structure and the correlations of the lowest lying states for even and odd isotopes.

  6. Chemical, multi-isotopic (Li-B-Sr-U-H-O) and thermal characterization of Triassic formation waters from the Paris Basin

    E-Print Network [OSTI]

    Boyer, Edmond

    of around 45 to 50°C. The study of uranium activity ratios for these Triassic formation waters allows us with water essentially resulting from a seawater-derived brine endmember diluted by meteoric waters. The data, uranium isotopes, oxygen isotopes, hydrogen isotopes, geothermometry, Trias, Paris Basin 1 hal-00563924

  7. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-08-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the previous research, the reference point of oxygen occupancy was determined and verified. In the current research, the oxygen occupancy was investigated at 1200 C as a function of oxygen activity and compared with that at 1000 C. The cause of bumps at about 200 C was also investigated by using different heating and cooling rates during TGA. The fracture toughness of LSFT and dual phase membranes at room temperature is an important mechanical property. Vicker's indentation method was used to evaluate this toughness. Through this technique, a K{sub Ic} (Mode-I Fracture Toughness) value is attained by means of semi-empirical correlations between the indentation load and the length of the cracks emanating from the corresponding Vickers indentation impression. In the present investigation, crack propagation behavior was extensively analyzed in order to understand the strengthening mechanisms involved in the non-transforming La based ceramic composites. Cracks were generated using Vicker's indenter and used to identify and evaluate the toughening mechanisms involved. Preliminary results of an electron microscopy study of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Modeling of the isotopic transients on operating membranes (LSCrF-2828 at 900 C) and a ''frozen'' isotope profile have been analyzed in conjunction with a 1-D model to reveal the gradient in oxygen diffusivity through the membrane under conditions of high chemical gradients.

  8. A Study of Oxygen Vacancy Formation and Annihilation in Submonolayer Coverages of TiO2 Dispersed on MCM-48

    E-Print Network [OSTI]

    Bell, Alexis

    A Study of Oxygen Vacancy Formation and Annihilation in Submonolayer Coverages of TiO2 Dispersed.932), suggesting the formation of oxygen vacancies. The fraction of Ti that could be reduced increased with TiO2 the TiO2 overlayer as the size of the titania patches increases. The amount of oxygen removed during

  9. Nonresonant ionization of oxygen molecules by femtosecond pulses: Plasma dynamics studied by time-resolved terahertz spectroscopy

    E-Print Network [OSTI]

    Apkarian, V. Ara

    contribution to laser plasmas generated in air,26 ionized oxygen O2 + plays an important role in the upperNonresonant ionization of oxygen molecules by femtosecond pulses: Plasma dynamics studied by time for exploring laser-induced ionization and plasma formation in gases. Plasma was produced in gaseous oxygen

  10. Oxygen enriched combustion system performance study. Phase 2: 100 percent oxygen enriched combustion in regenerative glass melters, Final report

    SciTech Connect (OSTI)

    Tuson, G.B.; Kobayashi, H.; Campbell, M.J.

    1994-08-01T23:59:59.000Z

    The field test project described in this report was conducted to evaluate the energy and environmental performance of 100% oxygen enriched combustion (100% OEC) in regenerative glass melters. Additional objectives were to determine other impacts of 100% OEC on melter operation and glass quality, and to verify on a commercial scale that an on-site Pressure Swing Adsorption oxygen plant can reliably supply oxygen for glass melting with low electrical power consumption. The tests constituted Phase 2 of a cooperative project between the United States Department of Energy, and Praxair, Inc. Phase 1 of the project involved market and technical feasibility assessments of oxygen enriched combustion for a range of high temperature industrial heating applications. An assessment of oxygen supply options for these applications was also performed during Phase 1, which included performance evaluation of a pilot scale 1 ton per day PSA oxygen plant. Two regenerative container glass melters were converted to 100% OEC operation and served as host sites for Phase 2. A 75 ton per day end-fired melter at Carr-Lowrey Glass Company in Baltimore, Maryland, was temporarily converted to 100% OEC in mid- 1990. A 350 tpd cross-fired melter at Gallo Glass Company in Modesto, California was rebuilt for permanent commercial operation with 100% OEC in mid-1991. Initially, both of these melters were supplied with oxygen from liquid storage. Subsequently, in late 1992, a Pressure Swing Adsorption oxygen plant was installed at Gallo to supply oxygen for 100% OEC glass melting. The particular PSA plant design used at Gallo achieves maximum efficiency by cycling the adsorbent beds between pressurized and evacuated states, and is therefore referred to as a Vacuum/Pressure Swing Adsorption (VPSA) plant.

  11. STUDY OF USING OXYGEN-ENRICHED COMBUSTION AIR FOR LOCOMOTIVE...

    Office of Scientific and Technical Information (OSTI)

    with specified efficiencies. The actual intake and exhaust valve events and the manifold control volumes and surface areas were obtained from a previous study conducted at the...

  12. Strontium Isotope Study of Coal Untilization By-products Interacting with Environmental Waters

    SciTech Connect (OSTI)

    Spivak-Birndorf, Lev J; Stewart, Brian W; Capo, Rosemary C; Chapman, Elizabeth C; Schroeder, Karl T; Brubaker, Tonya M

    2011-09-01T23:59:59.000Z

    Sequential leaching experiments on coal utilization by-products (CUB) were coupled with chemical and strontium (Sr) isotopic analyses to better understand the influence of coal type and combustion processes on CUB properties and the release of elements during interaction with environmental waters during disposal. Class C fly ash tended to release the highest quantity of minor and trace elements—including alkaline earth elements, sodium, chromium, copper, manganese, lead, titanium, and zinc—during sequential extraction, with bottom ash yielding the lowest. Strontium isotope ratios ({sup 87}Sr/{sup 86}Sr) in bulk-CUB samples (total dissolution of CUB) are generally higher in class F ash than in class C ash. Bulk-CUB ratios appear to be controlled by the geologic source of the mineral matter in the feed coal, and by Sr added during desulfurization treatments. Leachates of the CUB generally have Sr isotope ratios that are different than the bulk value, demonstrating that Sr was not isotopically homogenized during combustion. Variations in the Sr isotopic composition of CUB leachates were correlated with mobility of several major and trace elements; the data suggest that arsenic and lead are held in phases that contain the more radiogenic (high-{sup 87}Sr/{sup 86}Sr) component. A changing Sr isotope ratio of CUB-interacting waters in a disposal environment could forecast the release of certain strongly bound elements of environmental concern. This study lays the groundwork for the application of Sr isotopes as an environmental tracer for CUB–water interaction.

  13. Nitrogen and carbon isotope values of individual amino acids: a tool to study foraging ecology of penguins in the Southern Ocean

    E-Print Network [OSTI]

    Brest, Université de

    but further work is required to determine the trophic enrichment factors for compound-specific isotopeNitrogen and carbon isotope values of individual amino acids: a tool to study foraging ecology, 79360 Villiers-en-Bois, France Running header: Compound-specific isotope analysis and penguin isotopic

  14. An Oxygen Isotope Study Of Hydrothermal Alteration In The Lake City

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty EditCalifornia: Energy Resources Jump to:Almo,TransmissionOperations at the

  15. An Oxygen Isotope Study Of Silicates In The Larderello Geothermal Field,

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to:Ezfeedflag JumpID-fTriWildcat Place:Alvan BlanchAmiteIn TheContinental Scientific

  16. Isotope effect studies of the pyruvate-dependent histidine decarboxylase from Lactobacillus 30a

    SciTech Connect (OSTI)

    Abell, L.M.; O'Leary, M.H.

    1988-08-09T23:59:59.000Z

    The decarboxylation of histidine by the pyruvate-dependent histidine decarboxylase of Lactobacillus 30 a shows a carbon isotope effect k/sup 12//k/sup 13/ = 1.0334 +/- 0.0005 and a nitrogen isotope effect k/sup 14//k/sup 15/ = 0.9799 +/- 0.0006 at pH 4.8, 37/sup 0/C. The carbon isotope effect is slightly increased by deuteriation of the substrate and slightly decreased in D/sub 2/O. The observed nitrogen isotope effect indicates that the imine nitrogen in the substrate-Schiff base intermediate complex is ordinarily protonated, and the pH dependence of the carbon isotope effect indicates that both protonated and unprotonated forms of this intermediate are capable of undergoing decarboxylation. As with the pyridoxal 5'-phosphate dependent enzyme, Schiff base formation and decarboxylation are jointly rate-limiting, with the intermediate histidine-pyruvate Schiff base showing a decarboxylation/Schiff base hydrolysis ratio of 0.5-1.0 at pH 4.8. The decarboxylation transition state is more reactant-like for the pyruvate-dependent enzyme than for the pyridoxal 5'-phosphate dependent enzyme. These studies find no particular energetic or catalytic advantage to the use of pyridoxal 5'-phosphate over covalently bound pyruvate in catalysis of the decarboxylation of histidine.

  17. Study of asymmetric fission yield behavior from neutron-deficient Hg isotope

    SciTech Connect (OSTI)

    Perkasa, Y. S. [Department of Physics, Sunan Gunung Djati State Islamic University Bandung, Jl. A.H Nasution No. 105 Cibiru, Bandung (Indonesia); Waris, A., E-mail: awaris@fi.itb.ac.id; Kurniadi, R., E-mail: awaris@fi.itb.ac.id; Su'ud, Z., E-mail: awaris@fi.itb.ac.id [Nuclear Physics and Biophysics Research Division, Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesa No. 10 Bandung 40132 (Indonesia)

    2014-09-30T23:59:59.000Z

    A study of asymmetric fission yield behavior from a neutron-deficient Hg isotope has been conducted. The fission yield calculation of the neutron-deficient Hg isotope using Brownian Metropolis shape had showed unusual result at decreasing energy. In this paper, this interesting feature will be validated by using nine degree of scission shapes parameterization from Brosa model that had been implemented in TALYS nuclear reaction code. This validation is intended to show agreement between both model and the experiment result. The expected result from these models considered to be different due to dynamical properties that implemented in both models.

  18. Semiclassical wave packet study of anomalous isotope effect in ozone formation

    E-Print Network [OSTI]

    Reid, Scott A.

    Semiclassical wave packet study of anomalous isotope effect in ozone formation Evgeny Vetoshkin represent the metastable O3 * species and play a central role in the process of ozone formation.1063/1.2778432 I. INTRODUCTION Ozone O3 is formed in the stratosphere as a product of the following recombination

  19. Isotopic Tracer Studies of Reaction Pathways for Propane Oxidative Dehydrogenation on Molybdenum Oxide Catalysts

    E-Print Network [OSTI]

    Iglesia, Enrique

    Isotopic Tracer Studies of Reaction Pathways for Propane Oxidative Dehydrogenation on Molybdenum of propane over ZrO2-supported MoOx catalysts. Competitive reactions of C3H6 and CH3 13 CH2CH3 showed combustion of propene, or by direct combustion of propane. A mixture of C3H8 and C3D8 undergoes oxidative

  20. Experimental and theoretical studies of oxygen gradients in rat pial microvessels

    E-Print Network [OSTI]

    Popel, Aleksander S.

    no substantial impact on the transmural PO2 gradient. Journal of Cerebral Blood Flow & Metabolism (2008) 28, 1597Experimental and theoretical studies of oxygen gradients in rat pial microvessels Maithili Sharan1 near cortical arterioles and transmural PO2 gradients in the pial arterioles of the rat. Under control

  1. Cluster structures in Oxygen isotopes

    E-Print Network [OSTI]

    N. Furutachi; M. kimura; A. Doté; Y. Kanada-En'yo; S. oryu

    2007-06-01T23:59:59.000Z

    Cluster structure of 16O,18O and 20O is investigated by the antisymmettrized molecular dynamics (AMD) plus generator coordinate method (GCM). We have found the K^{\\pi}=0$_2^+$ and 0$_1^-$ rotational bands of 18O that have the prominent 14C+\\alpha cluster structure. Clustering systematics becomes richer in 20O. We suggest the K^{\\pi}=0$_2^+$ band that is the mixture of the 12C+\\alpha+4n and 14C+6He cluster structures, and the K^{\\pi}=0$_1^-$ band that has the 14C+6He cluster structure. The K^{\\pi}=0$_3^+$ and 0$_2^-$ bands that have the prominent 16C+\\alpha cluster structure are also found.

  2. A lithium isotopic study of sub-greenschist to greenschist facies metamorphism in an accretionary prism, New Zealand

    E-Print Network [OSTI]

    Mcdonough, William F.

    A lithium isotopic study of sub-greenschist to greenschist facies metamorphism in an accretionary November 2010 Editor: R.W. Carlson Keywords: lithium slab-derived fluids accretionary prism quartz veins. Introduction The fluid-mobile element lithium increasingly receives attention because of the large isotopic

  3. A theoretical and experimental study of pressure broadening of the oxygen A-band by helium

    SciTech Connect (OSTI)

    Grimminck, Dennis L. A. G.; Spiering, Frans R.; Janssen, Liesbeth M. C.; Avoird, Ad van der; Zande, Wim J. van der; Groenenboom, Gerrit C., E-mail: Gerritg@theochem.ru.nl [Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

    2014-05-28T23:59:59.000Z

    The rotationally resolved magnetic dipole absorption spectrum of the oxygen A-band b{sup 1}?{sub g}{sup +}(v=0)?X{sup 3}?{sub g}{sup ?}(v=0) perturbed by collisions with helium was studied theoretically using the impact approximation. To calculate the relaxation matrix, scattering calculations were performed on a newly computed helium-oxygen (b{sup 1}?{sub g}{sup +}) interaction potential as well as on a helium-oxygen (X{sup 3}?{sub g}{sup ?}) interaction potential from the literature. The calculated integrated line cross sections and broadening coefficients are in good agreement with experimental results from the literature. Additionally, cavity ring-down experiments were performed in the wings of the spectral lines for a quantitative study of line-mixing, i.e., the redistribution of rotational line intensities by helium-oxygen collisions. It is shown that inclusion of line-mixing in the theory is required to reproduce the experimentally determined absolute absorption strengths as a function of the density of the helium gas.

  4. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-02-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. The in situ electrical conductivity and Seebeck coefficient measurements were made on LSFT at 1000 and 1200 C over the oxygen activity range from air to 10{sup -15} atm. The electrical conductivity measurements exhibited a p to n type transition at an oxygen activity of 1 x 10{sup -10} at 1000 C and 1 x 10{sup -6} at 1200 C. Thermogravimetric studies were also carried out over the same oxygen activities and temperatures. Based on the results of these measurements, the chemical and mechanical stability range of LSFT were determined and defect structure was established. The studies on the fracture toughness of the LSFT and dual phase membranes exposed to air and N{sub 2} at 1000 C was done and the XRD and SEM analysis of the specimens were carried out to understand the structural and microstructural changes. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affect the mechanical properties. A complete transformation of fracture behavior was observed in the N{sub 2} treated LSFT samples. Further results to investigate the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Recent results on transient kinetic data are presented. The 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model is used to study ''frozen'' profiles in patterned or composite membranes.

  5. A Mass Spectrometry Study of Isotope Separation in the Laser Plume

    E-Print Network [OSTI]

    Suen, Timothy Wu

    2012-01-01T23:59:59.000Z

    Zhang, and J. A. Nees, “Isotope Enrichment in Laser-AblationA. Naik, “Comment on “Isotope Enrichment in Laser-AblationP. Pronko, “Isotope separation and enrichment by ultrafast

  6. Stable isotopes of authigenic minerals in variably-saturated fractured tuff

    SciTech Connect (OSTI)

    Weber, D.S.; Evans, D.D.

    1988-11-01T23:59:59.000Z

    Identifying stable isotope variation and mineralogical changes in fractured rock may help establish the history of climatic and geomorphological processes that might affect the isolation properties of a waste repository site. This study examines the use of the stable isotope ratios of oxygen ({sup 18}O/{sup 16}O) and carbon ({sup 13}C/{sup 12}C) in authigenic minerals as hydrogeochemical tools tracing low-temperature rock-water interaction in variably-saturated fractured stuff. Isotopic compositions of fracture-filling and rock matrix minerals in the Apache Leap tuff, near Superior, Arizona were concordant with geothermal temperatures and in equilibrium with water isotopically similar to present-day meteoric water and groundwater. Oxygen and carbon isotope ratios of fracture-filling, in unsaturated fractured tuff, displayed an isotopic gradient believed to result from near-surface isotopic enrichment due to evaporation rather than the effects of rock-water interaction. Oxygen isotope ratios of rock matrix opal samples exhibited an isotopic gradient believed to result from, leaching and reprecipitation of silica at depth. Methods and results can be used to further define primary flowpaths and the movement of water in variably-saturated fractured rock. 71 refs., 23 figs., 3 tabs.

  7. Preparation and characterisation of isotopically enriched Ta$_2$O$_5$ targets for nuclear astrophysics studies

    E-Print Network [OSTI]

    A. Caciolli; D. A. Scott; A. Di Leva; A. Formicola; M. Aliotta; M. Anders; A. Bellini; D. Bemmerer; C. Broggini; M. Campeggio; P. Corvisiero; R. Depalo; Z. Elekes; Zs. Fülöp; G. Gervino; A. Guglielmetti; C. Gustavino; Gy. Gyürky; G. Imbriani; M. Junker; M. Marta; R. Menegazzo; E. Napolitani; P. Prati; V. Rigato; V. Roca; C. Rolfs; C. Rossi Alvarez; E. Somorjai; C. Salvo; O. Straniero; F. Strieder; T. Szücs; F. Terrasi; H. P. Trautvetter; D. Trezzi

    2012-10-01T23:59:59.000Z

    The direct measurement of reaction cross sections at astrophysical energies often requires the use of solid targets of known thickness, isotopic composition, and stoichiometry that are able to withstand high beam currents for extended periods of time. Here, we report on the production and characterisation of isotopically enriched Ta$_2$O$_5$ targets for the study of proton-induced reactions at the Laboratory for Underground Nuclear Astrophysics facility of the Laboratori Nazionali del Gran Sasso. The targets were prepared by anodisation of tantalum backings in enriched water (up to 66% in $^{17}$O and up to 96% in $^{18}$O). Special care was devoted to minimising the presence of any contaminants that could induce unwanted background reactions with the beam in the energy region of astrophysical interest. Results from target characterisation measurements are reported, and the conclusions for proton capture measurements with these targets are drawn.

  8. Preparation and characterisation of isotopically enriched Ta$_2$O$_5$ targets for nuclear astrophysics studies

    E-Print Network [OSTI]

    Caciolli, A; Di Leva, A; Formicola, A; Aliotta, M; Anders, M; Bellini, A; Bemmerer, D; Broggini, C; Campeggio, M; Corvisiero, P; Depalo, R; Elekes, Z; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Marta, M; Menegazzo, R; Napolitani, E; Prati, P; Rigato, V; Roca, V; Rolfs, C; Alvarez, C Rossi; Somorjai, E; Salvo, C; Straniero, O; Strieder, F; Szücs, T; Terrasi, F; Trautvetter, H P; Trezzi, D

    2012-01-01T23:59:59.000Z

    The direct measurement of reaction cross sections at astrophysical energies often requires the use of solid targets of known thickness, isotopic composition, and stoichiometry that are able to withstand high beam currents for extended periods of time. Here, we report on the production and characterisation of isotopically enriched Ta$_2$O$_5$ targets for the study of proton-induced reactions at the Laboratory for Underground Nuclear Astrophysics facility of the Laboratori Nazionali del Gran Sasso. The targets were prepared by anodisation of tantalum backings in enriched water (up to 66% in $^{17}$O and up to 96% in $^{18}$O). Special care was devoted to minimising the presence of any contaminants that could induce unwanted background reactions with the beam in the energy region of astrophysical interest. Results from target characterisation measurements are reported, and the conclusions for proton capture measurements with these targets are drawn.

  9. Final Progress Report: Isotope Identification Algorithm for Rapid and Accurate Determination of Radioisotopes Feasibility Study

    SciTech Connect (OSTI)

    Rawool-Sullivan, Mohini [Los Alamos National Laboratory; Bounds, John Alan [Los Alamos National Laboratory; Brumby, Steven P. [Los Alamos National Laboratory; Prasad, Lakshman [Los Alamos National Laboratory; Sullivan, John P. [Los Alamos National Laboratory

    2012-04-30T23:59:59.000Z

    This is the final report of the project titled, 'Isotope Identification Algorithm for Rapid and Accurate Determination of Radioisotopes,' PMIS project number LA10-HUMANID-PD03. The goal of the work was to demonstrate principles of emulating a human analysis approach towards the data collected using radiation isotope identification devices (RIIDs). It summarizes work performed over the FY10 time period. The goal of the work was to demonstrate principles of emulating a human analysis approach towards the data collected using radiation isotope identification devices (RIIDs). Human analysts begin analyzing a spectrum based on features in the spectrum - lines and shapes that are present in a given spectrum. The proposed work was to carry out a feasibility study that will pick out all gamma ray peaks and other features such as Compton edges, bremsstrahlung, presence/absence of shielding and presence of neutrons and escape peaks. Ultimately success of this feasibility study will allow us to collectively explain identified features and form a realistic scenario that produced a given spectrum in the future. We wanted to develop and demonstrate machine learning algorithms that will qualitatively enhance the automated identification capabilities of portable radiological sensors that are currently being used in the field.

  10. Inductively coupled plasma mass spectrometry for stable isotope metabolic tracer studies of living systems

    SciTech Connect (OSTI)

    Luong, E.

    1999-05-10T23:59:59.000Z

    This dissertation focuses on the development of methods for stable isotope metabolic tracer studies in living systems using inductively coupled plasma single and dual quadrupole mass spectrometers. Sub-nanogram per gram levels of molybdenum (Mo) from human blood plasma are isolated by the use of anion exchange alumina microcolumns. Million-fold more concentrated spectral and matrix interferences such as sodium, chloride, sulfate, phosphate, etc. in the blood constituents are removed from the analyte. The recovery of Mo from the alumina column is 82 {+-} 5% (n = 5). Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is utilized for the quantitative ultra-trace concentration determination of Mo in bovine and human blood samples. The average Mo concentration in reference bovine serum determined by this method is 10.2 {+-} 0.4 ng/g, while the certified value is 11.5 {+-} 1.1 ng/g (95% confidence interval). The Mo concentration of one pool of human blood plasma from two healthy male donors is 0.5 {+-} 0.1 ng/g. The inductively coupled plasma twin quadrupole mass spectrometer (ICP-TQMS) is used to measure the carbon isotope ratio from non-volatile organic compounds and bio-organic molecules to assess the ability as an alternative analytical method to gas chromatography combustion isotope ratio mass spectrometry (GC-combustion-IRMS). Trytophan, myoglobin, and {beta}-cyclodextrin are chosen for the study, initial observation of spectral interference of {sup 13}C{sup +} with {sup 12}C{sup 1}H{sup +} comes from the incomplete dissociation of myoglobin and/or {beta}-cyclodextrin.

  11. Experimental and analytical study to model temperature profiles and stoichiometry in oxygen-enriched in-situ combustion

    E-Print Network [OSTI]

    Rodriguez, Jose Ramon

    2004-09-30T23:59:59.000Z

    EXPERIMENTAL AND ANALYTICAL STUDY TO MODEL TEMPERATURE PROFILES AND STOICHIOMETRY IN OXYGEN-ENRICHED IN-SITU COMBUSTION A Dissertation by JOSE RAMON RODRIGUEZ Submitted to the Office of Graduate Studies of Texas A... AND STOICHIOMETRY IN OXYGEN-ENRICHED IN-SITU COMBUSTION A Dissertation by JOSE RAMON RODRIGUEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR...

  12. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; N. Nagabhushana; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-02-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. Thermogravimetric analysis (TGA) was carried out on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} to investigate oxygen deficiency ({delta}) of the sample. The TGA was performed in a controlled atmosphere using oxygen, argon, carbon monoxide and carbon dioxide with adjustable gas flow rates. In this experiment, the weight loss and gain of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} was directly measured by TGA. The weight change of the sample was evaluated at between 600 and 1250 C in air or 1000 C as a function of oxygen partial pressure. The oxygen deficiencies calculated from TGA data as a function of oxygen activity and temperature will be estimated and compared with that from neutron diffraction measurement in air. The LSFT and LSFT/CGO membranes were fabricated from the powder obtained from Praxair Specialty Ceramics. The sintered membranes were subjected to microstructure analysis and hardness analysis. The LSFT membrane is composed of fine grains with two kinds of grain morphology. The grain size distribution was characterized using image analysis. In LSFT/CGO membrane a lot of grain pullout was observed from the less dense, porous phase. The hardness of the LSFT and dual phase membranes were studied at various loads. The hardness values obtained from the cross section of the membranes were also compared to that of the values obtained from the surface. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. Measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} as a function of temperature an oxygen partial pressure are reported. Further analysis of the dilatometry data obtained previously is presented. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The CO-CO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

  13. Mechanistic studies of photo-induced proton-coupled electron transfer and oxygen atom transfer reactions in model systems

    E-Print Network [OSTI]

    Hodgkiss, Justin M. (Justin Mark), 1978-

    2007-01-01T23:59:59.000Z

    Time-resolved optical spectroscopy has been employed for mechanistic studies in model systems designed to undergo photo-induced proton-coupled electron transfer (PCET) and oxygen atom transfer (OAT) reactions, both of which ...

  14. A study of helium-3 activation applied to the determination of oxygen in germanium 

    E-Print Network [OSTI]

    Francis, Georgann

    1972-01-01T23:59:59.000Z

    A STUDY OF HELIUM-g ACTIVATION APPLIED TO THE DETERMINATION OF OXYGEN IN GERNAMUM A Thesis by Georgann Francis Submitted to the Graduate College of Texas A&M University in Partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE December 1972 MaJor SubJect: Chemistry A S GiiY 0" '. . .' i, liJi", ? g AG I'JATION ' PPLI 'i: TO Ii, . 3. . Ti:PNI i'. ATION O:iYGEI~I IN G 'iliiANIUIi A Thesi s by GcorGann Francis Approyed as to style and content by: ' /" YOhairican...

  15. Isotope Trace Studies of Diffusion in Silicates and of Geological Transport Processes Using Actinide Elements

    SciTech Connect (OSTI)

    Prof. G. J. Wasserburg

    2001-01-19T23:59:59.000Z

    Over the past year we have competed two studies of Os concentration and isotopic composition in rivers from the Himalayan uplift and in hydrothermal fluids from the Juan de Fuca Ridge. Both of these studies have been published. We have completed a study of paleo-climate in Soreq Cave, Israel, and have expanded our studies of the transport of U-Th through riverine and estuarine environments. We are completing two studies of weathering and transport in the vadose in two very different environments--one a tropical regime with a deep laterite profile and the other a northern arboreal forest with only a thin weathering zone. We have begun a new study of U-Th in aquifers with low water velocity.

  16. ForCent model development and testing using the Enriched Background Isotope Study experiment

    SciTech Connect (OSTI)

    Parton, W.J.; Hanson, P. J.; Swanston, C.; Torn, M.; Trumbore, S. E.; Riley, W.; Kelly, R.

    2010-10-01T23:59:59.000Z

    The ForCent forest ecosystem model was developed by making major revisions to the DayCent model including: (1) adding a humus organic pool, (2) incorporating a detailed root growth model, and (3) including plant phenological growth patterns. Observed plant production and soil respiration data from 1993 to 2000 were used to demonstrate that the ForCent model could accurately simulate ecosystem carbon dynamics for the Oak Ridge National Laboratory deciduous forest. A comparison of ForCent versus observed soil pool {sup 14}C signature ({Delta} {sup 14}C) data from the Enriched Background Isotope Study {sup 14}C experiment (1999-2006) shows that the model correctly simulates the temporal dynamics of the {sup 14}C label as it moved from the surface litter and roots into the mineral soil organic matter pools. ForCent model validation was performed by comparing the observed Enriched Background Isotope Study experimental data with simulated live and dead root biomass {Delta} {sup 14}C data, and with soil respiration {Delta} {sup 14}C (mineral soil, humus layer, leaf litter layer, and total soil respiration) data. Results show that the model correctly simulates the impact of the Enriched Background Isotope Study {sup 14}C experimental treatments on soil respiration {Delta} {sup 14}C values for the different soil organic matter pools. Model results suggest that a two-pool root growth model correctly represents root carbon dynamics and inputs to the soil. The model fitting process and sensitivity analysis exposed uncertainty in our estimates of the fraction of mineral soil in the slow and passive pools, dissolved organic carbon flux out of the litter layer into the mineral soil, and mixing of the humus layer into the mineral soil layer.

  17. Fundamental studies of heterostructured oxide thin film electrocatalysts for oxygen reduction at high temperatures

    E-Print Network [OSTI]

    Crumlin, Ethan J

    2012-01-01T23:59:59.000Z

    Searching for active and cost-effective catalysts for oxygen electrocatalysis is essential for the development of efficient clean electrochemical energy technologies. Perovskite oxides are active for surface oxygen exchange ...

  18. In Situ Ambient Pressure X-ray Photoelectron Spectroscopy Studies of Lithium-Oxygen Redox Reactions

    E-Print Network [OSTI]

    Lu, Yi-chun

    The lack of fundamental understanding of the oxygen reduction and oxygen evolution in nonaqueous electrolytes significantly hinders the development of rechargeable lithium-air batteries. Here we employ a solid-state ...

  19. Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate-Scale Hydrodynamic Model

    SciTech Connect (OSTI)

    Yang, Zhaoqing; Khangaonkar, Tarang; Labiosa, Rochelle G.; Kim, Taeyun

    2010-11-30T23:59:59.000Z

    The Washington State Department of Ecology contracted with Pacific Northwest National Laboratory to develop an intermediate-scale hydrodynamic and water quality model to study dissolved oxygen and nutrient dynamics in Puget Sound and to help define potential Puget Sound-wide nutrient management strategies and decisions. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or dominate human impacts to dissolved oxygen levels in the sensitive areas. In this study, an intermediate-scale hydrodynamic model of Puget Sound was developed to simulate the hydrodynamics of Puget Sound and the Northwest Straits for the year 2006. The model was constructed using the unstructured Finite Volume Coastal Ocean Model. The overall model grid resolution within Puget Sound in its present configuration is about 880 m. The model was driven by tides, river inflows, and meteorological forcing (wind and net heat flux) and simulated tidal circulations, temperature, and salinity distributions in Puget Sound. The model was validated against observed data of water surface elevation, velocity, temperature, and salinity at various stations within the study domain. Model validation indicated that the model simulates tidal elevations and currents in Puget Sound well and reproduces the general patterns of the temperature and salinity distributions.

  20. Study of iron structure stability in high temperature molten lead-bismuth eutectic with oxygen injection using molecular dynamics simulation

    SciTech Connect (OSTI)

    Arkundato, Artoto [Physics Department, Faculty of Mathematical and Natural Sciences, Jember University, Jl. Kalimantan 37 Jember (Indonesia); Su'ud, Zaki [Physics Department, Faculty of Mathematical and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung (Indonesia); Sudarko [Chemistry Department, Faculty of Mathematical and Natural Sciences, Jember University, Jl. Kalimantan 37 Jember (Indonesia); Shafii, Mohammad Ali [Physics Department, Faculty of Mathematical and Natural Sciences, Andalas University, Padang (Indonesia); Celino, Massimo [ENEA, CR Casaccia, Via Anguillarese 301, Rome (Italy)

    2014-09-30T23:59:59.000Z

    Corrosion of structural materials in high temperature molten lead-bismuth eutectic is a major problem for design of PbBi cooled reactor. One technique to inhibit corrosion process is to inject oxygen into coolant. In this paper we study and focus on a way of inhibiting the corrosion of iron using molecular dynamics method. For the simulation results we concluded that effective corrosion inhibition of iron may be achieved by injection 0.0532 wt% to 0.1156 wt% oxygen into liquid lead-bismuth. At this oxygen concentration the structure of iron material will be maintained at about 70% in bcc crystal structure during interaction with liquid metal.

  1. Isotope Tracer Studies of Diffusion in Sillicates and of Geological Transport Processes Using Actinide Elements

    SciTech Connect (OSTI)

    Wasserburg, Gerald J

    2008-07-31T23:59:59.000Z

    The objectives were directed toward understanding the transport of chemical species in nature, with particular emphasis on aqueous transport in solution, in colloids, and on particles. Major improvements in measuring ultra-low concentrations of rare elements were achieved. We focused on two areas of studies: (1) Field, laboratory, and theoretical studies of the transport and deposition of U, Th isotopes and their daughter products in natural systems; and (2) Study of calcium isotope fractionation effects in marine carbonates and in carbonates precipitated in the laboratory, under controlled temperature, pH, and rates of precipitation. A major study of isotopic fractionation of Ca during calcite growth from solution has been completed and published. It was found that the isotopic shifts widely reported in the literature and attributed to biological processes are in fact due to a small equilibrium fractionation factor that is suppressed by supersaturation of the solution. These effects were demonstrated in the laboratory and with consideration of the solution conditions in natural systems, where [Ca{sup 2+}] >> [CO{sub 3}{sup 2-}] + [HCO{sub 3}{sup -}]. The controlling rate is not the diffusion of Ca, as was earlier proposed, but rather the rate of supply of [CO{sub 3}{sup 2-}] ions to the interface. This now opens the issues of isotopic fractionation of many elements to a more physical-chemical approach. The isotopic composition of Ca {Delta}({sup 44}Ca/{sup 40}Ca) in calcite crystals has been determined relative to that in the parent solutions by TIMS using a double spike. Solutions were exposed to an atmosphere of NH{sub 3} and CO{sub 2}, provided by the decomposition of (NH4)2CO3. Alkalinity, pH, and concentrations of CO{sub 3}{sup 2-}, HCO{sub 3}{sup -}, and CO{sub 2} in solution were determined. The procedures permitted us to determine {Delta}({sup 44}Ca/{sup 40}Ca) over a range of pH conditions, with the associated ranges of alkalinity. Two solutions with greatly different Ca concentrations were used, but, in all cases, the condition [Ca] >> [CO{sub 3}{sup 2-}] was met. A wide range in {Delta}({sup 44}Ca/{sup 40}Ca) was found for the calcite crystals, extending from 0.04 {+-} 0.13 to -1.34 {+-} 0.15 {per_thousand}, generally anticorrelating with the amount of Ca removed from the solution. The results show that {Delta}({sup 44}Ca/{sup 40}Ca) is a linear function of the saturation state of the solution with respect to calcite ({Omega}). The two parameters are very well correlated over a wide range in {Omega} for each solution with a given [Ca]. Solutions, which were vigorously stirred, showed a much smaller range in {Delta}({sup 44}Ca/{sup 40}Ca) and gave values of -0.42 {+-} 0.14 {per_thousand}, with the largest effect at low {Omega}. It is concluded that the diffusive flow of CO{sub 3}{sup 2-} into the immediate neighborhood of the crystal-solution interface is the rate-controlling mechanism and that diffusive transport of Ca{sup 2+} is not a significant factor. The data are simply explained by the assumptions that: (a) the immediate interface of the crystal and the solution is at equilibrium with {Delta}({sup 44}Ca/{sup 40}Ca) {approx} -1.5 {+-} 0.25 {per_thousand}, and (b) diffusive inflow of CO{sub 3}{sup 2-} causes supersaturation, thus precipitating Ca from the regions, exterior to the narrow zone of equilibrium. We consider this model to be a plausible explanation of the available data reported in the literature. The well-resolved but small and regular isotope fractionation shifts in Ca are thus not related to the diffusion of very large hydrated Ca complexes, but rather due to the ready availability of Ca in the general neighborhood of the crystal solution interface. The largest isotopic shift which occurs is a small equilibrium effect which is then subdued by supersaturation precipitation for solutions where [Ca{sup 2+}] >> [CO{sub 3}{sup 2-}] + [HCO{sub 3}{sup -}]. It is shown that there is a clear temperature dependence of the net isotopic shifts, which is simply due to changes in {Omega}

  2. oxygen-plasma | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    oxygen-plasma oxygen-plasma Leads No leads are available at this time. Conversion of 1,2-Propylene Glycol on Rutile TiO2(110). Abstract: We have studied the reactions of...

  3. Elevated CO2 increases tree-level intrinsic water use efficiency: insights from carbon and oxygen isotope analyses in tree rings across three forest FACE sites

    SciTech Connect (OSTI)

    Battipaglia, Giovanna [Second University of Naples; Saurer, Matthias [Paul Scherrer Institut, Villigen, Switzerland; Cherubini, Paulo [WSL Swiss Federal Institute for Forest, Snow and Landscape Research; Califapietra, Carlo [University of Tuscia; McCarthy, Heather R [Duke University; Norby, Richard J [ORNL; Cotrufo, M. Francesca [Colorado State University, Fort Collins

    2013-01-01T23:59:59.000Z

    Elevated CO2 increases intrinsic water use efficiency (WUEi) of forests, but the magnitude of this effect and its interaction with climate is still poorly understood. We combined tree ring analysis with isotope measurements at three Free Air CO2 Enrichment (FACE, POP-EUROFACE, in Italy; Duke FACE in North Carolina and ORNL in Tennessee, USA) sites, to cover the entire life of the trees. We used 13C to assess carbon isotope discrimination ( 13C ci/ca) and changes in WUEi, while direct CO2 effects on stomatal conductance were explored using 18O as a proxy. Across all the sites, elevated CO2 increased 13C-derived WUEi on average by 73% for Liquidambar styraciflua, 77% for Pinus taeda and 75% for Populus sp., but through different ecophysiological mechanisms. Our findings provide a robust means of predicting WUEi responses from a variety of tree species exposed to variable environmental conditions over time, and species-specific relationships that can help modeling elevated CO2 and climate impacts on forest productivity, carbon and water balances.

  4. Shell-model study of quadrupole collectivity in light tin isotopes

    E-Print Network [OSTI]

    Coraggio, L; Gargano, A; Itaco, N; Kuo, T T S

    2015-01-01T23:59:59.000Z

    A realistic shell-model study is performed for neutron-deficient tin isotopes up to mass A=108. All shell-model ingredients, namely two-body matrix elements, single-particle energies, and effective charges for electric quadrupole transition operators, have been calculated by way of the many-body perturbation theory, starting from a low-momentum interaction derived from the high-precision CD-Bonn free nucleon-nucleon potential. The focus has been put on the enhanced quadrupole collectivity of these nuclei, which is testified by the observed large B(E2;0+ -> 2+)s. Our results evidence the crucial role played by the Z=50 cross-shell excitations that need to be taken into account explicitly to obtain a satisfactory theoretical description of light tin isotopes. We find also that a relevant contribution comes from the calculated neutron effective charges, whose magnitudes exceed the standard empirical values. An original double-step procedure has been introduced to reduce effectively the model space in order to ov...

  5. Shell-model study of quadrupole collectivity in light tin isotopes

    E-Print Network [OSTI]

    L. Coraggio; A. Covello; A. Gargano; N. Itaco; T. T. S. Kuo

    2015-04-13T23:59:59.000Z

    A realistic shell-model study is performed for neutron-deficient tin isotopes up to mass A=108. All shell-model ingredients, namely two-body matrix elements, single-particle energies, and effective charges for electric quadrupole transition operators, have been calculated by way of the many-body perturbation theory, starting from a low-momentum interaction derived from the high-precision CD-Bonn free nucleon-nucleon potential. The focus has been put on the enhanced quadrupole collectivity of these nuclei, which is testified by the observed large B(E2;0+ -> 2+)s. Our results evidence the crucial role played by the Z=50 cross-shell excitations that need to be taken into account explicitly to obtain a satisfactory theoretical description of light tin isotopes. We find also that a relevant contribution comes from the calculated neutron effective charges, whose magnitudes exceed the standard empirical values. An original double-step procedure has been introduced to reduce effectively the model space in order to overcome the computational problem.

  6. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-10-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, Moessbauer spectroscopy was used to study the local environmentals of LSFT with various level of oxygen deficiency. Ionic valence state, magnetic interaction and influence of Ti on superexchange are discussed Stable crack growth studies on Dense OTM bars provided by Praxair were done at elevated temperature, pressure and elevated conditions. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. The initial measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Neutron diffraction measurements of the same composition are in agreement with both the stoichiometry and the kinetic behavior observed in coulometric titration measurements. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The COCO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

  7. Helium isotope study of geothermal features in Chile with field and laboratory data

    SciTech Connect (OSTI)

    Dobson, Patrick

    2013-02-11T23:59:59.000Z

    Helium isotope and stable isotope data from the El Tatio, Tinginguirica, Chillan, and Tolhuaca geothermal systems, Chile. Data from this submission are discussed in: Dobson, P.F., Kennedy, B.M., Reich, M., Sanchez, P., and Morata, D. (2013) Effects of volcanism, crustal thickness, and large scale faulting on the He isotope signatures of geothermal systems in Chile. Proceedings, 38th Workshop on Geothermal Reservoir Engineering, Stanford University, Feb. 11-13, 2013

  8. Isotope effect studies of the pyridoxal 5'-phosphate dependent histidine decarboxylase from Morganella morganii

    SciTech Connect (OSTI)

    Abell, L.M.; O'Leary, M.H.

    1988-08-09T23:59:59.000Z

    The pyridoxal 5'-phosphate dependent histidine decarboxylase from Morganella morganii shows a nitrogen isotope effect k/sup 14//k/sup 15/ = 0.9770 +/- 0.0021, a carbon isotope effect k/sup 12//k/sup 13/ = 1.0308 +/- 0.0006, and a carbon isotope effect for L-(..cap alpha..-/sup 2/H)histidine of 1.0333 +/- 0.0001 at pH 6.3, 37/sup 0/C. These results indicate that the overall decarboxylation rate is limited jointly by the rate of Schiff base interchange and by the rate of decarboxylation. Although the observed isotope effects are quite different from those for the analogous glutamate decarboxylase from Escherichia coli, the intrinsic isotope effects for the two enzymes are essentially the same. The difference in observed isotope effects occurs because of a roughly twofold difference in the partitioning of the pyridoxal 5'-phosphate-substrate Schiff base between decarboxylation and Schiff base interchange. The observed nitrogen isotope effect requires that the imine nitrogen in this Schiff base is protonated. Comparison of carbon isotope effects for deuteriated and undeuteriated substrates reveals that the deuterium isotope effect on the decarboxylation step is about 1.20; thus, in the transition state for the decarboxylation step, the carbon-carbon bond is about two-thirds broken.

  9. Simulation study of dose enhancement in a cell due to nearby carbon and oxygen in particle radiotherapy

    E-Print Network [OSTI]

    Shin, Jae Ik; Cho, Sungho; Kim, Eun Ho; Song, Yongkeun; Jung, Won-Gyun; Yoo, SeungHoon; Shin, Dongho; Lee, Se Byeong; Yoon, Myonggeun; Incerti, Sebastian; Geso, Moshi; Rosenfeld, Anatoly B

    2015-01-01T23:59:59.000Z

    The aim of this study is to investigate the dose-deposition enhancement by alpha-particle irradiation in a cellular model using carbon and oxygen chemical compositions.A simulation study was performed to study dose enhancement due to carbon and oxygen for a human cell where Geant4 code used for the alpha-particle irradiation to the cellular phantom. The characteristic of dose enhancement in the nucleus and cytoplasm by the alpha-particle radiation was investigated based on concentrations of the carbon and oxygen compositions and was compared with those by gold and gadolinium.The results show that both the carbon and oxygen-induced dose enhancement was found to be more effective than those of gold and gadolinium. We found that the dose-enhancement effect was more dominant in the nucleus than in the cytoplasm if carbon or oxygen is uniformly distributed in a whole cell. In the condition that the added chemical composition was inserted only into the cytoplasm, the effect of the dose enhancement in nucleus become...

  10. Environmental TEM study of electron beam induced electro-chemistry of Pr????Ca????MnO? catalysts for oxygen evolution

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mildner, Stephanie; Zhu, Yimei; Beleggia, Marco; Mierwaldt, Daniel; Hansen, Thoma Willum; Wagner, Jakob Birkedal; Yazdi, Sadegh; Kasama, Takeshi; Ciston, Jim; Jooss, Christian

    2015-03-12T23:59:59.000Z

    Environmental Transmission Electron Microscopy (ETEM) studies offer great potential for gathering atomic scale information on the electronic state of electrodes in contact with reactants but also pose big challenges due to the impact of the high energy electron beam. In this article, we present an ETEM study of a Pr????Ca????MnO? (PCMO) thin film electro-catalyst for water splitting and oxygen evolution in contact with water vapor. We show by means of off-axis electron holography and electrostatic modeling that the electron beam gives rise to a positive electric sample potential due to secondary electron emission. The value of the electric potential dependsmore »on the primary electron flux, the sample -conductivity and grounding, and gas properties. We present evidence that two observed electro-chemical reactions are driven by a beam induced electrostatic potential of the order of a volt. The first reaction is an anodic electrochemical oxidation reaction of oxygen depleted amorphous PCMO which results in recrystallization of the perovskite structure. The second reaction is oxygen evolution which can be detected by the oxidation of a silane additive and formation of SiO2–x at catalytically active surfaces. Recently published in-situ XANES observation of subsurface oxygen vacancy formation during oxygen evolution at a positive potential [³²] is confirmed in this work. The quantification of beam induced potentials is an important step for future controlled electro-chemical experiments in an ETEM.« less

  11. Geochemical, oxygen, and neodymium isotope compositions of metasediments from the Abitibi greenstone belt and Pontiac Subprovince, Canada: Evidence for ancient crust and Archean terrane juxtaposition

    SciTech Connect (OSTI)

    Feng, R.; Kerrich, R. (Univ. of Saskatchewan, Saskatoon (Canada)); Maas, R. (Curtin Univ. of Technology, Perth (Australia))

    1993-02-01T23:59:59.000Z

    The Abitibi greenstone belt (AGB) and Pontiac Subprovince (PS) in the southwestern Superior Province are adjacent greenstone-plutonic and metasedimentary-dominated terranes, respectively, separated by a major fault zone. Metasediments from these two contrasting terranes are compared in terms of major- and trace-element and O- and Nd-isotope compositions, and detrital zircon ages. The following two compositional populations of metasediments are present in the low-grade, Abitibi southern volcanic zone: (1) a mafic-element-enriched population (MEP) characterized by flat, depleted REE patterns; enhanced Mg, Cr, Co, Ni, and Sc; low-incompatible-element contents; and minor or absent normalized negative troughs at Nb, Ta, and Ti; and (2) a low-mafic-element population (LMEP) featuring LREE-enriched patterns; enhanced Rb, Cs, Ba, Th, and U contents; and pronounced normalized negative troughs at Nb, Ta, and Ti. These geochemical features are interpreted to indicate that the MEP sediments were derived from an ultramafic- and mafic-dominated oceanic provenance, whereas the LMEP sediments represent mixtures of mafic and felsic are source rocks. The PS metasediments are essentially indistinguishable from Abitibi LMEP on the basis of major-element and transition metal abundances, suggesting comparable types of source rocks and degrees of maturity, but are distinct in terms of some trace elements and O-isotope compositions. The Pontiac metasediments are depleted in [sup 18]O and enriched in Cs, Ba, Pb, Th, U, Nb, Ta, Hf, Zr, and total REE and also have higher ratios of Rb/K, Cs/Rb, Ba/Rb, Ta/Nb, Th/La, and Ba/La relative to the Abitibi LMEP. Two subtypes of REE patterns have been identified in PS metasediments. The first subtype is interpreted to be derived from provenances of mixed mafic and felsic volcanic rocks, whereas the Eu-depleted type has features that are typical of post-Archean sediments or Archean K-rich granites and volcanic equivalents. 100 refs., 9 figs., 4 tabs.

  12. Mollusc shell periostracum as an alternative to tissue in isotopic studies

    E-Print Network [OSTI]

    Delong, Michael D.; Thorp, James H.

    2009-06-01T23:59:59.000Z

    such as mollusc shells, however, are often abundant because of their ease of storage. We used stable isotope ratios of carbon and nitrogen to determine if there was a relationship between the isotopic composition of the periostracum of the shell and soft body...

  13. Limited lithium isotopic fractionation during progressive metamorphic dehydration in metapelites: A case study

    E-Print Network [OSTI]

    Mcdonough, William F.

    Limited lithium isotopic fractionation during progressive metamorphic dehydration in metapelites-zone metamorphism far removed from the pluton to partially melted rocks adjacent to the pluton. Lithium on the aureole scale. Published by Elsevier B.V. Keywords: Lithium; Isotope fractionation; Metamorphic

  14. Isotopic Tracer Studies of Propane Reactions on H-ZSM5 Zeolite Joseph A. Biscardi and Enrique Iglesia*

    E-Print Network [OSTI]

    Iglesia, Enrique

    Isotopic Tracer Studies of Propane Reactions on H-ZSM5 Zeolite Joseph A. Biscardi and Enrique unlabeled products from mixtures of propene and propane-2-13C reactants. Aromatic products of propane-2-13C-Parmer) that allowed differential reactor operation (propane reactions were

  15. Applied Radiation and Isotopes 58 (2003) 333338 Study of air pollutants in Hong Kong using energy dispersive

    E-Print Network [OSTI]

    Yu, K.N.

    2003-01-01T23:59:59.000Z

    Applied Radiation and Isotopes 58 (2003) 333­338 Study of air pollutants in Hong Kong using energy were located within the area defined by vehicular emissions. As such, the main air pollutant monitoring site also fell into this same identified area, so the main air pollutant could also be vehicular

  16. A systematic study of carbon-oxygen white dwarf mergers: mass combinations for Type Ia supernovae

    E-Print Network [OSTI]

    Sato, Yushi; Tanikawa, Ataru; Nomoto, Ken'ichi; Maeda, Keiichi; Hachisu, Izumi

    2015-01-01T23:59:59.000Z

    Mergers of two carbon-oxygen (CO) white dwarfs (WDs) have been considered as progenitors of Type Ia supernovae (SNe Ia). Based on smoothed particle hydrodynamics (SPH) simulations, previous studies claimed that mergers of CO WDs lead to an SN Ia explosion either in the dynamical merger phase or stationary rotating merger remnant phase. However, the mass range of CO WDs that lead to an SN Ia has not been clearly identified yet. In the present work, we perform systematic SPH merger simulations for the WD masses ranging from $0.5~M_{\\odot}$ to $1.1~M_{\\odot}$ with higher resolutions than the previous systematic surveys and examine whether or not carbon burning occurs dynamically or quiescently in each phase. We further study the possibility of SN Ia explosion and estimate the mass range of CO WDs that lead to an SN Ia. We found that when the both WDs are massive, i.e., in the mass range of $0.9~M_{\\odot} {\\le} M_{1,2} {\\le} 1.1~M_{\\odot}$, they can explode as an SN Ia in the merger phase. On the other hand, when...

  17. Stable isotope fractionation by thermal diffusion through partially molten wet and dry silicate rocks

    E-Print Network [OSTI]

    Bindeman, Ilya N.

    isotope redistribution by thermal diffusion leading to enrichment of light isotopes at the hot endStable isotope fractionation by thermal diffusion through partially molten wet and dry silicate 2012 Editor: T.M. Harrison Keywords: thermal diffusion hydrogen isotope separation oxygen isotopes

  18. Understanding denitrification with stable isotope measurements of N2: proof of concept study

    E-Print Network [OSTI]

    Downer, Roswell Curtis

    2004-01-01T23:59:59.000Z

    The biologically mediated removal of nitrogen from estuarine and shallow coastal waters was investigated using a new method for the determination of N? isotope ratios. This method employs the use of a chromatographic separation technique to purify...

  19. Coral Isotope Record of Environmental Change in the Northwest Gulf of Mexico

    E-Print Network [OSTI]

    Miner, Adrian

    2013-08-30T23:59:59.000Z

    carbon and oxygen isotopes in coral skeletal material must be well understood. We have studied a Montastrea faveolata coral core from the Flower Garden Banks deposited over the 161 year period from 1844 to 2005. Annual growth bands revealed by X...

  20. Oxygen analyzer

    DOE Patents [OSTI]

    Benner, William H. (Danville, CA)

    1986-01-01T23:59:59.000Z

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N.sub.2), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable oxygen obtained by decomposing the sample at 1135.degree. C., or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135.degree. C. as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N.sub.2, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  1. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-11-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the current research, the electrical conductivity and Seebeck coefficient were measured as a function of temperature in air. Based on these measurements, the charge carrier concentration, net acceptor dopant concentration, activation energy of conduction and mobility were estimated. The studies on the fracture toughness of the LSFT and dual phase membranes at room temperature have been completed and reported previously. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affects the mechanical properties. To study the effect of temperature on the membranes when exposed to an inert environment, the membranes (LAFT and Dual phase) were heat treated at 1000 C in air and N{sub 2} atmosphere and hardness and fracture toughness of the membranes were studied after the treatment. The indentation method was used to find the fracture toughness and the effect of the heat treatment on the mechanical properties of the membranes. Further results on the investigation of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appears to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model will serve to study ''frozen'' profiles in patterned or composite membranes.

  2. Thermodynamic study of the MWG system/components and measurement of the oxygen partial pressure in the heat source capsule

    SciTech Connect (OSTI)

    David, D.J.

    1980-06-23T23:59:59.000Z

    A thermodynamic study of the Milliwatt Generator heat source capsule was performed to determine the effects of the oxide fuel on container materials at elevated temperatures in order to evaluate the factors affecting embrittlement of T-111 alloy. The study indicates that relatively slow oxidation of the T-111 of the capsule occurs during pretreatment. Yttrium added to the /sup 238/PuO/sub 2/ fuel charge is functioning in its designed role as an oxygen getter and is stabilizing at an O/Pu ratio of 1.75. The free energy of formation of hafnium oxide has been measured and found to be -70632 cal/mole; this suggests that the ability of hafnium to strongly function as an oxygen getter may be largely determined by the kinetics, and the free energy may play a lesser role.

  3. Isotope separation by selective photodissociation of glyoxal

    DOE Patents [OSTI]

    Marling, John B. (Pleasanton, CA)

    1976-01-01T23:59:59.000Z

    Dissociation products, mainly formaldehyde and carbon monoxide, enriched in a desired isotope of carbon, oxygen, or hydrogen are obtained by the selective photodissociation of glyoxal wherein glyoxal is subjected to electromagnetic radiation of a predetermined wavelength such that photon absorption excites and induces dissociation of only those molecules of glyoxal containing the desired isotope.

  4. Oxygen analyzer

    DOE Patents [OSTI]

    Benner, W.H.

    1984-05-08T23:59:59.000Z

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N/sub 2/), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable obtained by decomposing the sample at 1135/sup 0/C, or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135/sup 0/C as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N/sub 2/, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  5. Isotopic fractionations associated with phosphoric acid digestion of carbonate minerals: Insights from first-principles theoretical

    E-Print Network [OSTI]

    Goddard III, William A.

    Isotopic fractionations associated with phosphoric acid digestion of carbonate minerals: Insights for oxygen- and carbon-isotope analysis of carbonate minerals since 1950, and was recently established of oxygen isotope acid digestion fractionations among different carbonate minerals. We suggest these results

  6. Dispersal of Adult Culex Mosquitoes in an Urban West Nile Virus Hotspot: A Mark-Capture Study Incorporating Stable Isotope Enrichment of Natural Larval Habitats

    E-Print Network [OSTI]

    Hamer, Gabriel L.; Anderson, Tavis K.; Donovan, Danielle J.; Brawn, Jeffrey D.; Krebs, Bethany L.; Gardner, Allison M.; Ruiz, Marilyn O.; Brown, William M.; Kitron, Uriel D.; Newman, Christina M.; Goldberg, Tony L.; Walker, Edward D.

    2014-03-27T23:59:59.000Z

    Dispersal is a critical life history behavior for mosquitoes and is important for the spread of mosquito-borne disease. We implemented the first stable isotope mark-capture study to measure mosquito dispersal, focusing on Culex pipiens in southwest...

  7. Studies of Plutonium-238 Production at the High Flux Isotope Reactor

    SciTech Connect (OSTI)

    Lastres, Oscar [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Chandler, David [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)] [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Jarrell, Joshua J [ORNL] [ORNL; Maldonado, G. Ivan [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK)

    2011-01-01T23:59:59.000Z

    The High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) is a versatile 85 MW{sub th}, pressurized, light water-cooled and -moderated research reactor. The core consists of two fuel elements, an inner fuel element (IFE) and an outer fuel element (OFE), each constructed of involute fuel plates containing high-enriched-uranium (HEU) fuel ({approx}93 wt% {sup 235}U/U) in the form of U{sub 3}O{sub 8} in an Al matrix and encapsulated in Al-6061 clad. An over-moderated flux trap is located in the center of the core, a large beryllium reflector is located on the outside of the core, and two control elements (CE) are located between the fuel and the reflector. The flux trap and reflector house numerous experimental facilities which are used for isotope production, material irradiation, and cold/thermal neutron scattering. Over the past five decades, the US Department of Energy (DOE) and its agencies have been producing radioisotope power systems used by the National Aeronautics and Space Administration (NASA) for unmanned, long-term space exploration missions. Plutonium-238 is used to power Radioisotope Thermoelectric Generators (RTG) because it has a very long half-life (t{sub 1/2} {approx} 89 yr.) and it generates about 0.5 watts/gram when it decays via alpha emission. Due to the recent shortage and uncertainty of future production, the DOE has proposed a plan to the US Congress to produce {sup 238}Pu by irradiating {sup 237}Np as early as in fiscal year 2011. An annual production rate of 1.5 to 2.0 kg of {sup 238}Pu is expected to satisfy these needs and could be produced in existing national nuclear facilities like HFIR and the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL). Reactors at the Savannah River Site were used in the past for {sup 238}Pu production but were shut down after the last production in 1988. The nation's {sup 237}Np inventory is currently stored at INL. A plan for producing {sup 238}Pu at US research reactor facilities such as the High Flux Isotope Reactor at ORNL has been initiated by the US DOE and NASA for space exploration needs. Two Monte Carlo-based depletion codes, TRITON (ORNL) and VESTA (IRSN), were used to study the {sup 238}Pu production rates with varying target configurations in a typical HFIR fuel cycle. Preliminary studies have shown that approximately 11 grams and within 15 to 17 grams of {sup 238}Pu could be produced in the first irradiation cycle in one small and one large VXF facility, respectively, when irradiating fresh target arrays as those herein described. Important to note is that in this study we discovered that small differences in assumptions could affect the production rates of Pu-238 observed. The exact flux at a specific target location can have a significant impact upon production, so any differences in how the control elements are modeled as a function of exposure, will also cause differences in production rates. In fact, the surface plot of the large VXF target Pu-238 production shown in Figure 3 illustrates that the pins closest to the core can potentially have production rates as high as 3 times those of pins away from the core, thus implying that a cycle-to-cycle rotation of the targets may be well advised. A methodology for generating spatially-dependent, multi-group self-shielded cross sections and flux files with the KENO and CENTRM codes has been created so that standalone ORIGEN-S inputs can be quickly constructed to perform a variety of {sup 238}Pu production scenarios, i.e. combinations of the number of arrays loaded and the number of irradiation cycles. The studies herein shown with VESTA and TRITON/KENO will be used to benchmark the standalone ORIGEN.

  8. Isotope tracer studies of diffusion in silicates and of geological transport processes in aqueous systems using actinide elements

    SciTech Connect (OSTI)

    Wasserburg, G.J.

    1999-02-01T23:59:59.000Z

    This research program has moved ahead with success in several areas. The isotopic composition of osmium in seawater and in some rivers was directly determined for the first time. The concentration of osmium was first estimated in both seawater and rivers. A major effort was directed toward the transport of the U,Th series nuclides in a watershed in Sweden. A serious effort was directed at developing a transport model for the U,Th series nuclides in aquifers. A detailed study of {sup 238}U-{sup 230}Th dating of a cave in Israel was carried out collaboratively. The Os-Re fractionation between silicate and sulfide melts were determined in MORB basalts and glasses and the isotopic composition of Os was measured in sulfide samples.

  9. Simple, rapid method for the preparation of isotopically labeled formaldehyde

    DOE Patents [OSTI]

    Hooker, Jacob Matthew (Port Jefferson, NY); Schonberger, Matthias (Mains, DE); Schieferstein, Hanno (Aabergen, DE); Fowler, Joanna S. (Bellport, NY)

    2011-10-04T23:59:59.000Z

    Isotopically labeled formaldehyde (*C.sup..sctn.H.sub.2O) is prepared from labeled methyl iodide (*C.sup..sctn.H.sub.3I) by reaction with an oxygen nucleophile having a pendant leaving group. The mild and efficient reaction conditions result in good yields of *C.sup..sctn.H.sub.2O with little or no *C isotopic dilution. The simple, efficient production of .sup.11CH.sub.2O is described. The use of the .sup.11CH.sub.2O for the formation of positron emission tomography tracer compounds is described. The reaction can be incorporated into automated equipment available to radiochemistry laboratories. The isotopically labeled formaldehyde can be used in a variety of reactions to provide radiotracer compounds for imaging studies as well as for scintillation counting and autoradiography.

  10. Isotopes in Environmental and Health Studies Vol. 41, No. 1, March 2005, 6985

    E-Print Network [OSTI]

    Mora, Miguel A.

    of environmental pollution of this portion of the Texas­Mexico border. Keywords: Birds; Carbon-13; Contaminants along the U.S. border with Mexico. We collected swallows during 1999 and 2000 from eight locations along gradient in the Texas­ Mexico border and to discern if stable isotopes could help discriminate between

  11. Helium isotope study of geothermal features in Chile with field and laboratory data

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Dobson, Patrick

    Dobson, P.F., Kennedy, B.M., Reich, M., Sanchez, P., and Morata, D. (2013) Effects of volcanism, crustal thickness, and large scale faulting on the He isotope signatures of geothermal systems in Chile. Proceedings, 38th Workshop on Geothermal Reservoir Engineering, Stanford University, Feb. 11-13, 2013

  12. Circumstellar {sup 12}C/{sup 13}C isotope ratios from millimeter observations of CN and CO: Mixing in carbon- and oxygen-rich stars

    SciTech Connect (OSTI)

    Milam, S. N.; Woolf, N. J.; Ziurys, L. M. [Department of Chemistry, University of Arizona, Tucson, AZ 85721 (United States)], E-mail: Stefanie.N.Milam@nasa.gov, E-mail: nwoolf@as.arizona.edu, E-mail: lziurys@as.arizona.edu

    2009-01-01T23:59:59.000Z

    A survey of the {sup 12}C/{sup 13}C ratio toward circumstellar envelopes has been conducted at millimeter wavelengths using the facilities of the Arizona Radio Observatory (ARO). The ratios were obtained for a sample of local C- and O-rich asymptotic giant branch and supergiant stars from observations of the {sup 12}C and {sup 13}C isotopologues of CO and CN, respectively. The J = 1 {yields} 0 transitions of both molecules were observed at {lambda} = 3 mm using the ARO 12 m telescope, while the J = 2 {yields} 1 lines of the two species were measured using the ARO Sub-Millimeter Telescope (SMT) at {lambda} = 1 mm. The {sup 12}C/{sup 13}C ratios were determined from the CO data by modeling both transitions simultaneously with a circumstellar radiative transfer code, which can account for the high opacities present in the emission from this species. In the case of CN, the hyperfine structure was used to evaluate opacity effects. Ratios obtained independently from CO and CN are in good agreement. For the C-rich envelopes, the ratios fall in the range {sup 12}C/{sup 13}C {approx} 25-90, while the O-rich shells have values of 10-35. Ratios of {sup 12}C/{sup 13}C {approx} 3-14 are found for the supergiant stars, with the exception of VY CMa, where the values lie in the range 25-46. All ratios obtained in this study are {<=} 89, the solar value, suggesting that substantial carbon-13 enrichment may be currently occurring in the local interstellar medium. A qualitative model was constructed based on first and third dredge-up convective mixing that can reproduce the observed ratios. Substantial mixing of H-burning products must occur to explain the ratios in the O-rich objects, while a wide range of {sup 12}C/{sup 13}C values can be generated by only a few percent mixing of He-burning ashes in the C-rich case. The {sup 12}C/{sup 13}C ratios obtained in this study should help improve stellar yield models and contribute to the understanding of Galactic chemical evolution.

  13. XANES, EXAFS and Kbeta spectroscopic studies of the oxygen-evolving complex in Photosystem II

    SciTech Connect (OSTI)

    Robblee, John H.

    2000-12-01T23:59:59.000Z

    A key question for the understanding of photosynthetic water oxidation is whether the four oxidizing equivalents necessary to oxidize water to dioxygen are accumulated on the four Mn ions of the oxygen evolving complex (OEC), or whether some ligand-centered oxidations take place before the formation and release of dioxygen during the S{sub 3} {r_arrow} [S{sub 4}] {r_arrow} S{sub 0} transition. Progress in instrumentation and flash sample preparation allowed us to apply Mn K{beta} X-ray emission spectroscopy (Kb XES) to this problem for the first time. The K{beta} XES results, in combination with Mn X-ray absorption near-edge structure (XANES) and electron paramagnetic resonance (EPR) data obtained from the same set of samples, show that the S{sub 2} {r_arrow} S{sub 3} transition, in contrast to the S{sub 0} {r_arrow} S{sub 1} and S{sub 1} {r_arrow} S{sub 2} transitions, does not involve a Mn-centered oxidation. This is rationalized by manganese {mu}-oxo bridge radical formation during the S{sub 2} {r_arrow} S{sub 3} transition. Using extended X-ray absorption fine structure (EXAFS) spectroscopy, the local environment of the Mn atoms in the S{sub 0} state has been structurally characterized. These results show that the Mn-Mn distance in one of the di-{mu}-oxo-bridged Mn-Mn moieties increases from 2.7 {angstrom} in the S{sub 1} state to 2.85 {angstrom} in the S{sub 0} state. Furthermore, evidence is presented that shows three di-{mu}-oxo binuclear Mn{sub 2} clusters may be present in the OEC, which is contrary to the widely held theory that two such clusters are present in the OEC. The EPR properties of the S{sub 0} state have been investigated and a characteristic ''multiline'' signal in the S{sub 0} state has been discovered in the presence of methanol. This provides the first direct confirmation that the native S{sub 0} state is paramagnetic. In addition, this signal was simulated using parameters derived from three possible oxidation states of Mn in the S{sub 0} state. The dichroic nature of X-rays from synchrotron radiation and single-crystal Mn complexes have been exploited to selectively probe Mn-ligand bonds using XANES and EXAFS spectroscopy. The results from single-crystal Mn complexes show that dramatic dichroism exists in these complexes, and are suggestive of a promising future for single-crystal studies of PS II.

  14. A study of helium-3 activation applied to the determination of oxygen in germanium

    E-Print Network [OSTI]

    Francis, Georgann

    1972-01-01T23:59:59.000Z

    of a new oxygen standard for trace analys1s, The feas1bility of using thin alum1num foils is ex- am1ned, and their use under experimental conditions is illustrated. iv ACKNOWLEDGENENTS I would like to gratefully acknowledge Professor E. A... (Muscovite) ranging 1n thick- ness from 10 to 13 microns were used as standards, 12, 7 micron alum1num foils served as degraders, and as supplementary beam monitors, Irradiation Terminal and Focusing Irradiation of samples was carried out using...

  15. Glaciation, aridification, and carbon sequestration in the Permo-Carboniferous: The isotopic record from low latitudes

    E-Print Network [OSTI]

    Grossman, Ethan L.

    Glaciation, aridification, and carbon sequestration in the Permo-Carboniferous: The isotopic record and carbon sequestration in the Late Paleozoic, we have compiled new and published oxygen and carbon isotopic Carboniferous Stable isotopes Carbon cycling Brachiopods To evaluate the isotopic record of climate change

  16. Problems and prospects in future applications of stable isotopes in the life sciences and medicine

    SciTech Connect (OSTI)

    Matwiyoff, N.A.; Unkefer, C.J.; Walker, T.E.

    1982-01-01T23:59:59.000Z

    In the last decade, there has been a resurgence of interest in the use of stable isotopes of carbon, oxygen, and nitrogen in the life sciences and medicine fueled by the increased availability of the isotopes and isotopically labeled compounds and of instruments for their detection. Accelerated development of /sup 13/C, /sup 15/N, and /sup 17/ /sup 18/O can be expected in the future for studies of drug bioavailability, nutrition and body protein economy, viability of organs for transplant, and for non-invasive tests of metabolic diseases and dysfunctions. These accelerated developments depend on continued improvements in nmr and ms instrumentation and in methods for the synthesis of isotopically labeled compounds. The main part of this paper explores the possibilities of biosynthesis for the selective enrichment of natural products, especially amino acids, with /sup 13/C.

  17. Spectroscopic study of semipolar (112{sup ¯}2)-HVPE GaN exhibiting high oxygen incorporation

    SciTech Connect (OSTI)

    Schustek, Philipp, E-mail: philipp.schustek@gmail.com [Institute of Quantum Matter, Ulm University, 89081 Ulm (Germany); Research Unit, Parc Sanitari Sant Joan de Déu and Foundation Sant Joan de Déu, Esplugues de Llobregat, 08950, Barcelona (Spain); Hocker, Matthias; Thonke, Klaus [Institute of Quantum Matter, Ulm University, 89081 Ulm (Germany); Klein, Martin; Scholz, Ferdinand [Institute of Optoelectronics, Ulm University, 89081 Ulm (Germany); Simon, Ulrich [Scientific Computing Centre Ulm, Ulm University, 89081 Ulm (Germany)

    2014-10-28T23:59:59.000Z

    Spatially resolved luminescence and Raman spectroscopy investigations are applied to a series of (112{sup ¯}2)-GaN samples grown by hydride vapor phase epitaxy (HVPE) grown over an initial layer deposited by metal organic vapor phase epitaxy on patterned sapphire substrates. Whereas these two differently grown GaN layers are crystallographically homogeneous, they differ largely in their doping level due to high unintentional oxygen uptake in the HVPE layer. This high doping shows up in luminescence spectra, which can be explained by a free-electron recombination band for which an analytical model considering the Burstein-Moss shift, conduction band tailing, and the bandgap renormalization is included. Secondary ion mass spectrometry, Raman spectroscopy, and Hall measurements concordantly determine the electron density to be above 10{sup 19?}cm{sup ?3}. In addition, the strain state is assessed by Raman spectroscopy and compared to a finite element analysis.

  18. A neutron diffraction study of oxygen and nitrogen ordering in a kinetically stable orthorhombic iron doped titanium oxynitride

    SciTech Connect (OSTI)

    Wu, On Ying; Parkin, Ivan P [Department of Chemistry, Materials Chemistry Research Centre, University College London, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Hyett, Geoffrey, E-mail: g.hyett@leeds.ac.uk [School of Chemistry, University of Leeds, Leeds, LS2 9JT (United Kingdom)

    2012-06-15T23:59:59.000Z

    The synthesis of a polycrystalline powder sample of iron doped orthorhombic titanium oxynitride, Ti{sub 2.92}Fe{sub 0.01}O{sub 4.02}N{sub 0.98}, on the scale of 0.7 g has been achieved. This was conducted by the unusual route of delamination from a steel substrate of a thin film deposited using atmospheric pressure chemical vapour deposition. The structure of the titanium oxynitride is presented, determined from a combined analysis of X-ray and neutron powder diffraction data. The use of neutron diffraction allows the position of the oxygen and nitrogen ions in the material to be reported unambiguously for the first time. In this study Ti{sub 2.92}Fe{sub 0.01}O{sub 4.02}N{sub 0.98} is found to crystallise in the Cmcm space group, iso-structural pseudobrookite, with lattice parameters a=3.81080(6) A, b=9.6253(2) A, and c=9.8859(2) A, and contains partial oxygen-nitrogen ordering. Of the three anion sites in this structure one is exclusively occupied by oxygen, while the remaining two sites are occupied by oxygen and nitrogen in a disordered manner. Testing indicates that this iron doped titanium oxynitride is a metastable phase that decomposes above 700 Degree-Sign C into TiN and TiO{sub 2}, the thermodynamic products. - Graphical abstract: We report the synthesis of Ti{sub 2.92}Fe{sub 0.01}O{sub 4.02}N{sub 0.98} deposited as a thin film using atmospheric pressure chemical vapour deposition onto stainless steel, which is then delaminated to produce a polycrystalline powder sample. This powder sample was used in a neutron diffraction experiment, and analysis of this data has allowed the position of the oxygen and nitrogen ions in the material to be reported unambiguously for the first time. Ti{sub 2.92}Fe{sub 0.01}O{sub 4.02}N{sub 0.98} is found to crystallise in the Cmcm space group iso-structural pseudobrookite and contains partial oxygen-nitrogen ordering. Highlights: Black-Right-Pointing-Pointer Partial oxygen and nitrogen ordering has been observed using neutron diffraction. Black-Right-Pointing-Pointer A large powder sample has been made by removal of a CVD film from a steel substrate. Black-Right-Pointing-Pointer Structural details of Ti{sub 2.92}Fe{sub 0.01}O{sub 4.02}N{sub 0.98} are reported for the first time.

  19. Study of oxygen reduction mechanism on Ag modified1 Sm1.8Ce0.2CuO4 cathode for solid oxide fuel cell2

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    to oxygen dissociation and diffusion process.26 KEYWORDS: Solid oxide fuel cell; Silver infiltrationStudy of oxygen reduction mechanism on Ag modified1 Sm1.8Ce0.2CuO4 cathode for solid oxide fuel cell2 3 4 Li-Ping Sun1 -- Hui Zhao1 -- Qiang Li1 -- Li-Hua Huo1 -- Jean-Paul Viricelle*2 --5 Christophe

  20. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-05-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C in N{sub 2}. Space group of R3c was found to result in a better refinement and is used in this study. The difference for crystal structure, lattice parameters and local crystal chemistry for LSFT nearly unchanged when gas environment switched from air to N{sub 2}. Stable crack growth studies on Dense OTM bars provided by Praxair were done at room temperature in air. A bridge-compression fixture was fabricated to achieve stable pre-cracks from Vickers indents. Post fracture evaluation indicated stable crack growth from the indent and a regime of fast fracture. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. The thermal and chemical expansion of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were studied at 800 {le} T {le} 1000 C and at {approx} 1 x 10{sup -15} {le} pO{sub 2} {le} 0.21 atm. The thermal expansion coefficient of the sample was calculated from the dilatometric analysis in the temperature range between room temperature and 1200 C in air. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The CO-CO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

  1. ISOTOPE METHODS IN HOMOGENEOUS CATALYSIS.

    SciTech Connect (OSTI)

    BULLOCK,R.M.; BENDER,B.R.

    2000-12-01T23:59:59.000Z

    The use of isotope labels has had a fundamentally important role in the determination of mechanisms of homogeneously catalyzed reactions. Mechanistic data is valuable since it can assist in the design and rational improvement of homogeneous catalysts. There are several ways to use isotopes in mechanistic chemistry. Isotopes can be introduced into controlled experiments and followed where they go or don't go; in this way, Libby, Calvin, Taube and others used isotopes to elucidate mechanistic pathways for very different, yet important chemistries. Another important isotope method is the study of kinetic isotope effects (KIEs) and equilibrium isotope effect (EIEs). Here the mere observation of where a label winds up is no longer enough - what matters is how much slower (or faster) a labeled molecule reacts than the unlabeled material. The most careti studies essentially involve the measurement of isotope fractionation between a reference ground state and the transition state. Thus kinetic isotope effects provide unique data unavailable from other methods, since information about the transition state of a reaction is obtained. Because getting an experimental glimpse of transition states is really tantamount to understanding catalysis, kinetic isotope effects are very powerful.

  2. Structural evolution across the insulator-metal transition in oxygen-deficient BaTiO3-? studied using neutron total scattering and Rietveld analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jeong, I.-K.; Lee, Seunghun; Jeong, Se-Young; Won, C. J.; Hur, N.; Llobet, A.

    2011-08-01T23:59:59.000Z

    Oxygen-deficient BaTiO3-? exhibits an insulator-metal transition with increasing ?. We performed neutron total scattering measurements to study structural evolution across an insulator-metal transition in BaTiO3-?. Despite its significant impact on resistivity, slight oxygen reduction (?=0.09) caused only a small disturbance on the local doublet splitting of Ti-O bond. This finding implies that local polarization is well preserved under marginal electric conduction. In the highly oxygen-deficient metallic state (?=0.25), however, doublet splitting of the Ti-O bond became smeared. The smearing of the local Ti-O doublet is complemented with long-range structural analysis and demonstrates that the metallic conduction in the highly oxygen-reducedmore »BaTiO3-? is due to the appearance of nonferroelectric cubic lattice.« less

  3. Structural evolution across the insulator-metal transition in oxygen-deficient BaTiO3-? studied using neutron total scattering and Rietveld analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jeong, I.-K.; Lee, Seunghun; Jeong, Se-Young; Won, C. J.; Hur, N.; Llobet, A.

    2011-08-01T23:59:59.000Z

    Oxygen-deficient BaTiO3-? exhibits an insulator-metal transition with increasing ?. We performed neutron total scattering measurements to study structural evolution across an insulator-metal transition in BaTiO3-?. Despite its significant impact on resistivity, slight oxygen reduction (?=0.09) caused only a small disturbance on the local doublet splitting of Ti-O bond. This finding implies that local polarization is well preserved under marginal electric conduction. In the highly oxygen-deficient metallic state (?=0.25), however, doublet splitting of the Ti-O bond became smeared. The smearing of the local Ti-O doublet is complemented with long-range structural analysis and demonstrates that the metallic conduction in the highly oxygen-reduced BaTiO3-? is due to the appearance of nonferroelectric cubic lattice.

  4. Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate Scale Water Quality Model

    SciTech Connect (OSTI)

    Khangaonkar, Tarang; Sackmann, Brandon S.; Long, Wen; Mohamedali, Teizeen; Roberts, Mindy

    2012-10-01T23:59:59.000Z

    The Salish Sea, including Puget Sound, is a large estuarine system bounded by over seven thousand miles of complex shorelines, consists of several subbasins and many large inlets with distinct properties of their own. Pacific Ocean water enters Puget Sound through the Strait of Juan de Fuca at depth over the Admiralty Inlet sill. Ocean water mixed with freshwater discharges from runoff, rivers, and wastewater outfalls exits Puget Sound through the brackish surface outflow layer. Nutrient pollution is considered one of the largest threats to Puget Sound. There is considerable interest in understanding the effect of nutrient loads on the water quality and ecological health of Puget Sound in particular and the Salish Sea as a whole. The Washington State Department of Ecology (Ecology) contracted with Pacific Northwest National Laboratory (PNNL) to develop a coupled hydrodynamic and water quality model. The water quality model simulates algae growth, dissolved oxygen, (DO) and nutrient dynamics in Puget Sound to inform potential Puget Sound-wide nutrient management strategies. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or control human impacts to DO levels in the sensitive areas. The project did not include any additional data collection but instead relied on currently available information. This report describes model development effort conducted during the period 2009 to 2012 under a U.S. Environmental Protection Agency (EPA) cooperative agreement with PNNL, Ecology, and the University of Washington awarded under the National Estuary Program

  5. Time Resolved in Situ XAFS Study of the Electrochemical Oxygen Intercalation in SrFeO2.5 Brownmillerite Structure: Comparison with the Homologous SrCoO2.5 System

    E-Print Network [OSTI]

    Frenkel, Anatoly

    temperature oxygen ionic conductors are key materials for the development of the next generation solid oxideTime Resolved in Situ XAFS Study of the Electrochemical Oxygen Intercalation in SrFeO2 to reversibly intercalate oxygen in an electrochemical reaction at room temperature to reach SrMO3 stoichiometry

  6. DESIGN STUDY FOR A LOW-ENRICHED URANIUM CORE FOR THE HIGH FLUX ISOTOPE REACTOR, ANNUAL REPORT FOR FY 2010

    SciTech Connect (OSTI)

    Cook, David Howard [ORNL; Freels, James D [ORNL; Ilas, Germina [ORNL; Jolly, Brian C [ORNL; Miller, James Henry [ORNL; Primm, Trent [ORNL; Renfro, David G [ORNL; Sease, John D [ORNL; Pinkston, Daniel [ORNL

    2011-02-01T23:59:59.000Z

    This report documents progress made during FY 2010 in studies of converting the High Flux Isotope Reactor (HFIR) from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in performance to users from the current level. Studies are reported of support to a thermal hydraulic test loop design, the implementation of finite element, thermal hydraulic analysis capability, and infrastructure tasks at HFIR to upgrade the facility for operation at 100 MW. A discussion of difficulties with preparing a fuel specification for the uranium-molybdenum alloy is provided. Continuing development in the definition of the fuel fabrication process is described.

  7. Study of the Role of Terrestrial Processes in the Carbon Cycle Based on Measurements of the Abundance and Isotopic Composition of Atmospheric CO2

    SciTech Connect (OSTI)

    Stephen C. Piper; Ralph F. Keeling

    2012-01-03T23:59:59.000Z

    The main objective of this project was to continue research to develop carbon cycle relationships related to the land biosphere based on remote measurements of atmospheric CO2 concentration and its isotopic ratios 13C/12C, 18O/16O, and 14C/12C. The project continued time-series observations of atmospheric carbon dioxide and isotopic composition begun by Charles D. Keeling at remote sites, including Mauna Loa, the South Pole, and eight other sites. Using models of varying complexity, the concentration and isotopic measurements were used to study long-term change in the interhemispheric gradients in CO2 and 13C/12C to assess the magnitude and evolution of the northern terrestrial carbon sink, to study the increase in amplitude of the seasonal cycle of CO2, to use isotopic data to refine constraints on large scale changes in isotopic fractionation which may be related to changes in stomatal conductance, and to motivate improvements in terrestrial carbon cycle models. The original proposal called for a continuation of the new time series of 14C measurements but subsequent descoping to meet budgetary constraints required termination of measurements in 2007.

  8. UPS STUDY OF THE ADSORPTION OF OXYGEN ON REDUCED SrTi03 SURFACES

    E-Print Network [OSTI]

    Ferrer, S.

    2013-01-01T23:59:59.000Z

    Figure Captions Figure 1. UPS spectra of a reduced SrTi0 3 (Journal of Applied Physics UPS STUDY OF THE ADSORPTION OFof California. LBL 11614 UPS STUDY OF THE ADSORPTION OF

  9. from Isotope Production Facility

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cancer-fighting treatment gets boost from Isotope Production Facility April 13, 2012 Isotope Production Facility produces cancer-fighting actinium 2:32 Isotope cancer treatment...

  10. MECHANISTIC STUDIES OF ARYL-OXYGEN BOND ACTIVATION IN A NICKEL(0) DIPHOSPHINE-ETHER COMPLEX

    E-Print Network [OSTI]

    Winfree, Erik

    with nickel precursors was studied. A series of nickel(0) complexes containing nickel-arene interactions.1).1a,1b Quenching of the lithium species with an electrophilic species leads to the functionalization

  11. Isotope Geochemistry of Thermal and Nonthermal Waters in the...

    Open Energy Info (EERE)

    geothermal fluids display a positive oxygen 18 shift of not less than 2 because of rock-water isotopic exchange at 220-300C. The Valles geothermal system is capped by a...

  12. A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines

    SciTech Connect (OSTI)

    Westbrook, C K; Pitz, W J; Curran, H J

    2005-11-14T23:59:59.000Z

    A detailed chemical kinetic modeling approach is used to examine the phenomenon of suppression of sooting in diesel engines by addition of oxygenated hydrocarbon species to the fuel. This suppression, which has been observed experimentally for a few years, is explained kinetically as a reduction in concentrations of soot precursors present in the hot products of a fuel-rich diesel ignition zone when oxygenates are included. Oxygenates decrease the overall equivalence ratio of the igniting mixture, producing higher ignition temperatures and more radical species to consume more soot precursor species, leading to lower soot production. The kinetic model is also used to show how different oxygenates, ester structures in particular, can have different soot-suppression efficiencies due to differences in molecular structure of the oxygenated species.

  13. Stable Isotope Fractionations in Biogeochemical Reactive Transport

    E-Print Network [OSTI]

    Druhan, Jennifer Lea

    2012-01-01T23:59:59.000Z

    34 S fractionation . Summary A mesoscale study of isotopicion exchange and ! 44 Ca . A mesoscale study of isotopicmodeling and ! 34 S . A mesoscale study of isotopic

  14. Climatic isotope signals in tree rings masked by air pollution: A case study conducted along the Mont Blanc Tunnel access road (Western Alps, Italy)

    E-Print Network [OSTI]

    Climatic isotope signals in tree rings masked by air pollution: A case study conducted along, Switzerland h i g h l i g h t s air pollution on the climatic signal recorded in the d13 C chronologies. Air pollution loads strongly influence the photosynthetic process.

  15. A quantum Monte Carlo study of electron correlation in transition metal oxygen molecules

    E-Print Network [OSTI]

    Mitas, Lubos

    methods and their impacts on the electronic structure. We evaluate binding energies and compare the ac- curacy of various approaches including single and multi-reference trial wave functions in QMC. Ó 2003 to come. Most studies have employed mainstream approaches such as Hartree­Fock and post-Har- tree

  16. Climate change deduced from isotopes in tree rings

    SciTech Connect (OSTI)

    Pendall, E.G.; Leavitt, S.W.

    1997-11-01T23:59:59.000Z

    This paper describes the theory of carbon, hydrogen, and oxygen isotopic signatures in cellulose for the purpose of paleoclimatic reconstruction. Mechanisms governing tree ring cellulose isotopic variability are investigated, and applications to the southwestern United States are delineated. A monitoring program of pinyon trees and comparison to climatic parameters is briefly described. Variables measured included deviations in hydrogen and oxygen-18 isotopic composition in precipitation, soil water, stem and leaf water, and atmospheric vapor. Water from phloem tissue was found to be isotopically identical to the xylem sap, suggesting that cellulose precursors can exchange isotopically with source water before cellulose is made in the trunk, thus removing most of the isotopic signal from the leaves. Overall results suggest that, on arid sites in the southwestern US receiving adequate summer rain, a precipitation seasonality signal may be recorded. 21 refs., 2 figs.

  17. Isotopically controlled semiconductors

    E-Print Network [OSTI]

    Haller, Eugene E.

    2006-01-01T23:59:59.000Z

    16 Isotopically Controlled Semiconductors Eugene E. Hallerof isotopically engineered semiconductors; for outstandingisotopically controlled semiconductor crystals. This article

  18. Isotope Cancer Treatment Research at LANL

    ScienceCinema (OSTI)

    Weidner, John; Nortier, Meiring

    2014-06-02T23:59:59.000Z

    Los Alamos National Laboratory has produced medical isotopes for diagnostic and imaging purposes for more than 30 years. Now LANL researchers have branched out into isotope cancer treatment studies. New results show that an accelerator-based approach can produce clinical trial quantities of actinium-225, an isotope that has promise as a way to kill tumors without damaging surrounding healthy cells.

  19. Accurate determination of Curium and Californium isotopic ratios by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) in 248Cm samples for transmutation studies

    SciTech Connect (OSTI)

    Gourgiotis, A.; Isnard, H.; Aubert, M.; Dupont, E.; AlMahamid, I.; Cassette, P.; Panebianco, S.; Letourneau, A.; Chartier, F.; Tian, G.; Rao, L.; Lukens, W.

    2011-02-01T23:59:59.000Z

    The French Atomic Energy Commission has carried out several experiments including the mini-INCA (INcineration of Actinides) project for the study of minor-actinide transmutation processes in high intensity thermal neutron fluxes, in view of proposing solutions to reduce the radiotoxicity of long-lived nuclear wastes. In this context, a Cm sample enriched in {sup 248}Cm ({approx}97 %) was irradiated in thermal neutron flux at the High Flux Reactor (HFR) of the Laue-Langevin Institute (ILL). This work describes a quadrupole ICP-MS (ICP-QMS) analytical procedure for precise and accurate isotopic composition determination of Cm before sample irradiation and of Cm and Cf after sample irradiation. The factors that affect the accuracy and reproducibility of isotopic ratio measurements by ICP-QMS, such as peak centre correction, detector dead time, mass bias, abundance sensitivity and hydrides formation, instrumental background, and memory blank were carefully evaluated and corrected. Uncertainties of the isotopic ratios, taking into account internal precision of isotope ratio measurements, peak tailing, and hydrides formations ranged from 0.3% to 1.3%. This uncertainties range is quite acceptable for the nuclear data to be used in transmutation studies.

  20. Plutonium Isotopes in the Terrestrial Environment at the Savannah River Site, USA: A Long-Term Study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Armstrong, Christopher R.; Brant, Heather A.; Nuessle, Patterson R.; Hall, Gregory; Halverson, Justin E.; Cadieux, James R.

    2015-02-03T23:59:59.000Z

    This work presents the findings of a long term plutonium study at Savannah River Site (SRS) conducted between 2003 and 2013. Terrestrial environmental samples were obtained at Savannah River National Laboratory (SRNL) in A-area. Plutonium content and isotopic abundances were measured over this time period by alpha spectrometry and three stage thermal ionization mass spectrometry (3STIMS). Here we detail the complete sample collection, radiochemical separation, and measurement procedure specifically targeted to trace plutonium in bulk environmental samples. Total plutonium activities were determined to be not significantly above atmospheric global fallout. However, the 238Pu/239+240Pu activity ratios attributed to SRS are above atmospheric global fallout ranges. The 240Pu/239Pu atom ratios are reasonably consistent from year to year and are lower than fallout, while the 242Pu/239Pu atom ratios are higher than fallout values. Overall, the plutonium signatures obtained in this study reflect a mixture of weapons-grade, higher burn-up, and fallout material. This study provides a blue print for long term low level monitoring of plutonium in the environment.

  1. Numerical study of the effect of oxygenated blending compounds on soot formation in shock tubes

    SciTech Connect (OSTI)

    Boehm, H. [Physikalische Chemie I, Universitaet Bielefeld (Germany); Braun-Unkhoff, M. [Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany)

    2008-04-15T23:59:59.000Z

    This numerical study deals with the influence of blends on the amount of soot formed in shock tubes, which were simulated by assuming a homogeneous plug flow reactor model. For this purpose, first, the reaction model used here was validated against experimental results previously obtained in the literature. Then, the soot volume fractions of various mixtures of methyl tert-butyl ether (MTBE)-benzene, isobutene-benzene, methanol-benzene, and ethanol-benzene diluted in argon were simulated and compared to the results of benzene-argon pyrolysis at 1721 K and 5.4 MPa. For MTBE, isobutene, methanol, and ethanol, small amounts of additives to benzene-argon mixtures promoted soot formation, for the shock tube model assumed, while higher concentrations of these additives led to smaller soot volume fractions in comparison to pure benzene-argon pyrolysis. The most significant soot promotion effect was found for the additives MTBE and isobutene. The channel for MTBE decomposition producing isobutene and methanol is very effective at temperatures beyond 1200 K. Thus, both MTBE-benzene and isobutene-benzene mixtures diluted in argon showed rather similar behavior in regard to soot formation. Special emphasis was directed toward the causes for the concentration-dependent influence of the blends on the amount of soot formed. Aromatic hydrocarbons and acetylene were identified as key gas-phase species that determine the trends in the formation of soot of various mixtures. From reaction flux analysis for phenanthrene, it was deduced that the combinative routes including phenyl species play a major role in forming PAHs, especially at early reaction times. It is found that the additives play an important role in providing material to grow side chains, such as by reaction channels including phenylacetylene or benzyl, which are confirmed to form aromatic hydrocarbons and thus to influence the amount of soot formed, particularly when the concentrations of the blends are increased. (author)

  2. An intramolecular theory of the mass-independent isotope effect for ozone. I.

    E-Print Network [OSTI]

    Hathorn, Bryan C.

    An intramolecular theory of the mass-independent isotope effect for ozone. I. B. C. Hathorn and R-independent isotope effect for ozone formation and dissociation is described. The experiments include the enrichment and asymmetric ozone isotopomers, the enrichment of ozone formed from heavily enriched oxygen isotopes

  3. Measurements of stable isotope ratios in milk samples from a farm placed in the mountains of Transylvania

    SciTech Connect (OSTI)

    Magdas, D. A., E-mail: gabriela.cristea@itim-cj.ro; Cristea, G., E-mail: gabriela.cristea@itim-cj.ro; Bot, A.; Puscas, R.; Radu, S.; Mirel, V. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania)] [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania); Cordea, D. V.; Mihaiu, M. [University of Agricultural Science and Veterinary Medicine, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania)] [University of Agricultural Science and Veterinary Medicine, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania)

    2013-11-13T23:59:59.000Z

    Product origin is of great importance for consumers especially because its association in consumer's perception with food quality, freedom from disease or pollution. Stable isotope ratio analysis is a powerful technique in food authenticity and traceability control which has been introduced within the European wine industry to ensure authenticity of wine provenance and to detect adulteration. Isotopic ratios measurements have also been successfully to other food commodities like: fruit juices, honey and dairy foods. The ?{sup 18}O and ?{sup 2}H content in milk water reflects the isotope composition of the ground water drunk by animals. Seasonal effects are also very important: in summer, milk water contains higher ?{sup 18}O and ?{sup 2}H values due to the fresh plants that are ate by animals. Relative carbon stable isotope abundances in total milk reflect the isotopic composition of the diet fed to the dairy cows. In this study the hydrogen, oxygen and carbon isotopic composition of 15 milk samples coming from a unit placed in the mountains of Transylvania was investigated. The distribution of the obtained isotopic values was than discussed taking into account that all the animals were feed with the same type of forage and consumed water was taken from the same source.

  4. Carbon–Oxygen Bond Formation via Organometallic Baeyer–Villiger Transformations: A Computational Study on the Impact of Metal Identity

    SciTech Connect (OSTI)

    Figg, Travis M. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry and Center for Advanced Scientific Computing and Modeling; Webb, Joanna R. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemistry; Cundari, Thomas R. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry and Center for Advanced Scientific Computing and Modeling; Gunnoe, T. Brent [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemistry

    2012-02-01T23:59:59.000Z

    Metal-mediated formation of C–O bonds is an important transformation that can occur by a variety of mechanisms. Recent studies suggest that oxygen-atom insertion into metal–hydrocarbyl bonds in a reaction that resembles the Baeyer–Villiger transformation is a viable process. In an effort to identify promising new systems, this study is designed to assess the impact of metal identity on such O-atom insertions for the reaction [(bpy)xM(Me)(OOH)]n ? [(bpy)xM(OMe)(OH)]n (x = 1 or 2; bpy = 2,2'-bipyridyl; n is varied to maintain the d-electron count at d? or d?). Six d?-square-planar complexes (M = PtII, PdII, NiII, IrI, RhI, and CoI) and eight d?-octahedral systems (M = IrIII, RhIII, CoIII, FeII RuII, OsII, MnI, and TcI) are studied. Using density functional theory calculations, the structures and energies of ground-state and transition-state species are elucidated. This study shows clear trends in calculated ?G’s for the O-atom insertions. The organometallic Baeyer–Villiger insertions are favored by lower coordination numbers (x = 1 versus x = 2), earlier transition metals, and first-row (3d) transition metals.

  5. Geochemical and carbon isotopic studies of crude oil destruction, bitumen precipitation, and sulfate reduction in the deep Smackover Formation

    SciTech Connect (OSTI)

    Sassen, R. (Louisiana State Univ., Baton Rouge (USA))

    1988-01-01T23:59:59.000Z

    Crude oil generated by the Lower Smackover source facies migrated to Upper Smackover reservoirs where slow thermal cracking of crude oil resulted in the formation of gas-condensate and late solid bitumen. Ultimately, only pyrobitumen, methane, and nonhydrocarbon gases including hydrogen sulfide persist in the deepest Smackover reservoirs. The carbon isotopic compositions of crude oils became heavier during crude oil destruction. The carbon isotopic compositions of asphaltenes, NSO-compounds, and saturated hydrocarbons in late solid bitumen and the Lower Smackover source facies became isotopically lighter during crude oil destruction. It is suggested that some isotopically-light components from crude oils were incorporated in late solid bitumen by reactions involving thermochemical sulfate reduction. Thermochemical sulfate reduction and crude oil destruction occurred over a long span of geologic time at temperatures in the 120-150C range.

  6. Study of Gamow-Teller transitions in isotopes of titanium within the quasi particle random phase approximation

    E-Print Network [OSTI]

    Sadiye Cakmak; Jameel-Un Nabi; Tahsin Babacan; Cevad Selam

    2014-08-21T23:59:59.000Z

    The Gamow-Teller (GT) transition is inarguably one of the most important nuclear weak transitions of the spin-isosopin $\\sigma\\tau$ type. It has many applications in nuclear and astrophysics. These include, but are not limited to, r-process $\\beta$-decays, stellar electron captures, neutrino cooling rates, neutrino absorption and inelastic scattering on nuclei. The quasiparticle random phase approximation (QRPA) is an efficient way to generate GT strength distribution. In order to better understand both theoretical systematics and uncertainties, we compare the GT strength distributions, centroid and width calculations for $^{40-60}$Ti isotopes, using the pn-QRPA, Pyatov method (PM) and the Schematic model (SM). The pn-QRPA and SM are further sub-divided into three categories in order to highlight the role of particle-particle (pp) force and deformation of the nucleus in the GT strength calculations. In PM, we study only the influence of the pp force in the calculation. We also compare with experimental results and other calculations where available. We found that the inclusion of pp force and deformation significantly improves the performance of SM and pn-QRPA models. Incorporation of pp force leads to pinning down the centroid value in the PM. The calculated GT strength functions using the pn-QRPA (C) and SM (C) models are in reasonable agreement with measured data.

  7. A study of the remineralization of organic carbon in nearshore sediments using carbon isotopes

    E-Print Network [OSTI]

    McNichol, Ann P., 1956-

    1986-01-01T23:59:59.000Z

    A study of the remineralization of organic carbon was conducted in the organic-rich sediments of Buzzards Bay, MA. Major processes affecting the carbon chemistry in sediments are reflected by changes in the stable carbon ...

  8. Mitochondrial reactive oxygen species and cancer

    E-Print Network [OSTI]

    Chandel, Navdeep S

    Mitochondria produce reactive oxygen species (mROS) as a natural by-product of electron transport chain activity. While initial studies focused on the damaging effects of reactive oxygen species, a recent paradigm shift ...

  9. Kinetic isotope effects, dynamic effects, and mechanistic studies of organic reactions

    E-Print Network [OSTI]

    Wang, Zhihong

    2007-04-25T23:59:59.000Z

    yields two products in a ratio of 3.0 �± 0.5. Theoretical studies shows that only one transition structure is involved in the formation of both. Quasiclassical trajectory calculations on an MP2 surface give a prediction of a product ratio of 45:14 (3.2...

  10. Design Study for a Low-Enriched Uranium Core for the High Flux Isotope Reactor, Annual Report for FY 2006

    SciTech Connect (OSTI)

    Primm, R. T. [ORNL] [ORNL; Ellis, R. J. [ORNL] [ORNL; Gehin, J. C. [ORNL] [ORNL; Clarno, K. T. [ORNL] [ORNL; Williams, K. A. [ORNL] [ORNL; Moses, D. L. [ORNL] [ORNL

    2006-11-01T23:59:59.000Z

    Neutronics and thermal-hydraulics studies show that, for equivalent operating power [85 MW(t)], a low-enriched uranium (LEU) fuel cycle based on uranium-10 wt % molybdenum (U-10Mo) metal foil with radially, “continuously graded” fuel meat thickness results in a 15% reduction in peak thermal flux in the beryllium reflector of the High Flux Isotope Reactor (HFIR) as compared to the current highly enriched uranium (HEU) cycle. The uranium-235 content of the LEU core is almost twice the amount of the HEU core when the length of the fuel cycle is kept the same for both fuels. Because the uranium-238 content of an LEU core is a factor of 4 greater than the uranium-235 content, the LEU HFIR core would weigh 30% more than the HEU core. A minimum U-10Mo foil thickness of 84 ?m is required to compensate for power peaking in the LEU core although this value could be increased significantly without much penalty. The maximum U-10Mo foil thickness is 457?m. Annual plutonium production from fueling the HFIR with LEU is predicted to be 2 kg. For dispersion fuels, the operating power for HFIR would be reduced considerably below 85 MW due to thermal considerations and due to the requirement of a 26-d fuel cycle. If an acceptable fuel can be developed, it is estimated that $140 M would be required to implement the conversion of the HFIR site at Oak Ridge National Laboratory from an HEU fuel cycle to an LEU fuel cycle. To complete the conversion by fiscal year 2014 would require that all fuel development and qualification be completed by the end of fiscal year 2009. Technological development areas that could increase the operating power of HFIR are identified as areas for study in the future.

  11. Recent studies have demonstrated that limitations to oxygen transport in lizards occur within both the respiratory and

    E-Print Network [OSTI]

    Bennett, Albert F.

    both the respiratory and cardiovascular systems. The lateral flexions of the trunk that occur during this constraint by employing an accessory ventilatory mechanism called the gular pump, thus maintaining oxygen of the main veins in the abdominal compartment. Systemic venous return and ventricular preload are major

  12. Recoil Studies in the Reaction of 12-C Ions with the Enriched Isotope 118-Sn

    E-Print Network [OSTI]

    A. R. Balabekyan; A. S. Danagulyan; J. R. Drnoyan; N. A. Demekhina; G. H. Hovhannisyan; J. Adam; V. G. Kalinnikov; M. I. Krivopustov; V. S. Pronskikh; V. I. Stegailov; A. A. Solnyshkin; V. M. Tsoupko-Sitnikov; S. G. Mashnik; K. K. Gudima

    2009-05-04T23:59:59.000Z

    The recoil properties of the product nuclei from the interaction of 2.2 GeV/nucleon 12-C ions from Nuclotron of the Laboratory of High Energies (LHE), Joint Institute for Nuclear Research (JINR) at Dubna with a 118-Sn target have been studied using catcher foils. The experimental data were analyzed using the mathematical formalism of the standard two-step vector model. The results for 12-C ions are compared with those for deuterons and protons. Three different Los Alamos versions of the Quark-Gluon String Model (LAQGSM) were used for comparison with our experimental data.

  13. Comparative study of high-spin isomers in semi-magic $Z$=50 isotopic and $N$=82 isotonic chains

    E-Print Network [OSTI]

    Bhoomika Maheshwari; Ashok Kumar Jain; P. C. Srivastava

    2014-08-08T23:59:59.000Z

    A comparative study of high spin nuclear isomers observed in the semi-magic $Z$=50 isotopic and $N$=82 isotonic chains has been carried out. The ${11/2}^-$, ${10}^+$ and ${27/2}^-$ isomers, which occur commonly in both the chains, display nearly identical systematics in excitation energy and half-life. An energy gap of ${\\sim 4}$ MeV between the ${0^+}$ ground states and ${10}^+$ isomers and, the ${11/2}^-$ and ${27/2}^-$ isomers exists before the mid-shell, which becomes a constant ${\\sim 3}$ MeV after the mid-shell region. The large scale shell model calculations are able to reproduce the observed energy systematics for both the chains reasonably well. The shell model occupancies and the basic seniority rules have been used to fix the seniority quantum number. The seniority of all the isomeric states as well as those involved in the decay from$/$to the isomers have been assigned and the alignment properties are also discussed. The seniorities of the ${10}^+$ and ${27/2}^-$ isomeric states before the mid-shell are higher, which become lower after the mid-shell, due to the dominant role played by the $h_{11/2}$ orbital. The empirical systematics and the calculated results suggest that the change in the energy gap around the mid-shell, may be interpreted in terms of a change in the seniority of the isomeric states. However, the seniority of the ${11/2}^-$ state remains conserved throughout both the chains. The systematics of the half-lives in both the chains have been understood on the basis of seniority and decay modes. Predictions for new isomers have also been made based on these systematics.

  14. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect (OSTI)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2003-01-01T23:59:59.000Z

    In the present quarter, the possibility of using a more complex interfacial engineering approach to the development of reliable and stable oxygen transport perovskite ceramic membranes/metal seals is discussed. Experiments are presented and ceramic/metal interactions are characterized. Crack growth and fracture toughness of the membrane in the reducing conditions are also discussed. Future work regarding this approach is proposed are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

  15. Isotope characterization of shallow aquifers in the Horombe region, South of Madagascar

    E-Print Network [OSTI]

    Fareze, L P; Ramaroson, V; Andriambololona, Raoelina; Andriamiarintsoa, G; Razafitsalama, P R; Rahobisoa, J J; Randrianarison, H; Ranaivoarisoa, A; Marah, H

    2012-01-01T23:59:59.000Z

    The present study deals with the problem of evaluation of the recharge mechanism and the characterization of the groundwater flow system in the basement shallow aquifer, which is one of the groundwater resource in the semi-arid South region of Madagascar. Stable isotopes (deuterium and oxygen-18) and tritium are used to achieve with accuracy the hydrogeological and geochemical dynamics study. Chemical analysis is used to provide complementary information to the investigation. A space distribution of tritium concentration and isotopic composition in groundwater shows evidence of two opposite categories of aquifers, which is confirmed by the chemical analysis results and by the geological features of the study site. Some groundwater flow path directions have been identified in the study area thanks to the tritium concentration space distribution and the geological formation. Besides, the groundwater recharge of the shallow aquifers in the South of Madagascar has been characterized by the exponential mixing mode...

  16. Design Study for a Low-enriched Uranium Core for the High Flux Isotope Reactor, Annual Report for FY 2007

    SciTech Connect (OSTI)

    Primm, Trent [ORNL; Ellis, Ronald James [ORNL; Gehin, Jess C [ORNL; Ilas, Germina [ORNL; Miller, James Henry [ORNL; Sease, John D [ORNL

    2007-11-01T23:59:59.000Z

    This report documents progress made during fiscal year 2007 in studies of converting the High Flux Isotope Reactor (HFIR) from highly enriched uranium (HEU) fuel to low enriched uranium fuel (LEU). Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. A high volume fraction U/Mo-in-Al fuel could attain the same neutron flux performance as with the current, HEU fuel but materials considerations appear to preclude production and irradiation of such a fuel. A diffusion barrier would be required if Al is to be retained as the interstitial medium and the additional volume required for this barrier would degrade performance. Attaining the high volume fraction (55 wt. %) of U/Mo assumed in the computational study while maintaining the current fuel plate acceptance level at the fuel manufacturer is unlikely, i.e. no increase in the percentage of plates rejected for non-compliance with the fuel specification. Substitution of a zirconium alloy for Al would significantly increase the weight of the fuel element, the cost of the fuel element, and introduce an as-yet untried manufacturing process. A monolithic U-10Mo foil is the choice of LEU fuel for HFIR. Preliminary calculations indicate that with a modest increase in reactor power, the flux performance of the reactor can be maintained at the current level. A linearly-graded, radial fuel thickness profile is preferred to the arched profile currently used in HEU fuel because the LEU fuel media is a metal alloy foil rather than a powder. Developments in analysis capability and nuclear data processing techniques are underway with the goal of verifying the preliminary calculations of LEU flux performance. A conceptual study of the operational cost of an LEU fuel fabrication facility yielded the conclusion that the annual fuel cost to the HFIR would increase significantly from the current, HEU fuel cycle. Though manufacturing can be accomplished with existing technology, several engineering proof-of-principle tests would be required. The RERTR program is currently conducting a series of generic fuel qualification tests at the Advanced Test Reactor. A review of these tests and a review of the safety basis for the current, HEU fuel cycle led to the identification of a set of HFIR-specific fuel qualification tests. Much additional study is required to formulate a HFIR-specific fuel qualification plan from this set. However, one such test - creating a graded fuel profile across a flat foil - has been initiated with promising results.

  17. One electron oxygen reduction in room temperature ionic liquids: A comparative study of Butler-Volmer and Symmetric Marcus-Hush theories using microdisc electrodes

    E-Print Network [OSTI]

    Tanner, Eden E L; Barnes, Edward O; Compton, Richard G

    2015-01-01T23:59:59.000Z

    The voltammetry for the reduction of oxygen at a microdisc electrode is reported in two room temperature ionic liquids: 1-butyl-1-methylpyyrolidinium bis(trifluoromethylsulfonyl) imide ([Bmpyrr][NTf2]) and trihexyltetradecylphosphonium bis9trifluoromethylsulfonyl) imide ([P14,6,6,6][NTf2]) at 298 K. Simulated voltammograms using Butler-Volmer theory and Symmetric Marcus-Hush (SMH) theory were compared with experimental data. Butler-Volmer theory consistently provided experimental parameters with a higher level of certainty than SMH theory. A value of solvent reorganisation energy for oxygen reduction in ionic liquids was inferred for the first time as 0.4-0.5 eV, which is attributable to inner-sphere reorganisation with a negligible contribution from solvent reorganisation. The developed Butler-Volmer and Symmetric Marcus-Hush programs are also used to theoretically study the possibility of kinetically limited steady state currents, and to establish an approximate equivalence relationship between microdisc el...

  18. Mixed oxygen ion/electron-conducting ceramics for oxygen separation

    SciTech Connect (OSTI)

    Stevenson, J.W.; Armstrong, B.L.; Armstrong, T.R.; Bates, J.L.; Pederson, L.R.; Weber, W.J.

    1995-05-01T23:59:59.000Z

    Solid mixed-conducting electrolytes in the series La{sub l-x}A{sub x}Co{sub l-y}Fe{sub y}O{sub 3-{delta}} (A = Sr,Ca,Ba) are potentially useful as passive membranes to separate high purity oxygen from air and as cathodes in fuel cells. All of the compositions studied exhibited very high electrical conductivities. At lower temperatures, conductivities increased with increasing temperature, characterized by activation energies of 0.05 to 0.16 eV that are consistent with a small polaron (localized electronic carrier) conduction mechanism. At higher temperatures, electronic conductivities tended to decrease with increasing temperature, which is attributed to decreased electronic carrier populations associated with lattice oxygen loss. Oxygen ion conductivities were higher than that of yttria stabilized zirconia and increased with the cobalt content and also increased with the extent of divalent A-site substitution. Thermogravimetric studies were conducted to establish the extent of oxygen vacancy formation as a function of temperature, oxygen partial pressure, and composition. These vacancy populations strongly depend on the extent of A-site substitution. Passive oxygen permeation rates were established for each of the compositions as a function of temperature and oxygen partial pressure gradient. For 2.5 mm thick membranes in an oxygen vs nitrogen partial pressure gradient, oxygen fluxes at 900 C ranged from approximately 0.3 sccm/cm{sup 2} for compositions high in iron and with low amounts of strontium A-site substitution to approximately 0.8 sccm/cm{sup 2} for compositions high in cobalt and strontium. A-site substitution with calcium instead of strontium resulted in substantially lower fluxes.

  19. Physics with isotopically controlled semiconductors

    SciTech Connect (OSTI)

    Haller, E. E., E-mail: eehaller@lbl.gov [University of California at Berkeley, Department of Materials Science and Engineering (United States)

    2010-07-15T23:59:59.000Z

    This paper is based on a tutorial presentation at the International Conference on Defects in Semiconductors (ICDS-25) held in Saint Petersburg, Russia in July 2009. The tutorial focused on a review of recent research involving isotopically controlled semiconductors. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, is the most prominent effect for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples.

  20. Isotope Science and Production

    E-Print Network [OSTI]

    Isotope Science and Production 35 years of experience in isotope production, processing, and applications. Llllll Committed to the safe and reliable production of radioisotopes, products, and services nuclear materials in trucks and cargo containers. Isotopes for Threat Reduction Isotope production at Los

  1. Artificial oxygen transport protein

    DOE Patents [OSTI]

    Dutton, P. Leslie

    2014-09-30T23:59:59.000Z

    This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

  2. First-principles study of band gap engineering via oxygen vacancy doping in perovskite ABB'O? solid solutions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Qi, Tingting; Curnan, Matthew T.; Kim, Seungchul; Bennett, Joseph W.; Grinberg, Ilya; Rappe, Andrew M.

    2011-12-01T23:59:59.000Z

    Oxygen vacancies in perovskite oxide solid solutions are fundamentally interesting and technologically important. However, experimental characterization of the vacancy locations and their impact on electronic structure is challenging. We have carried out first-principles calculations on two Zr-modified solid solutions, Pb(Zn1/3Nb2/3)O? and Pb(Mg1/3Nb2/3)O?, in which vacancies are present. We find that the vacancies are more likely to reside between low-valent cation-cation pairs than high-valent cation-cation pairs. Based on the analysis of our results, we formulate guidelines that can be used to predict the location of oxygen vacancies in perovskite solid solutions. Our results show that vacancies can have a significant impact on both the conduction and valence band energies, in some cases lowering the band gap by ?0.5 eV. The effects of vacancies on the electronic band structure can be understood within the framework of crystal field theory.

  3. Experimental study on transmission of an overdriven detonation wave from propane/oxygen to propane/air

    SciTech Connect (OSTI)

    Li, J.; Lai, W.H. [National Cheng Kung University, Institute of Aeronautics and Astronautics, Tainan (China); Chung, K. [National Cheng Kung University, Aerospace Science and Technology Research Center, Tainan (China); Lu, F.K. [University of Texas at Arlington, Mechanical and Aerospace Engineering Department, Aerodynamics Research Center, TX 76019 (United States)

    2008-08-15T23:59:59.000Z

    Two sets of experiments were performed to achieve a strong overdriven state in a weaker mixture by propagating an overdriven detonation wave via a deflagration-to-detonation transition (DDT) process. First, preliminary experiments with a propane/oxygen mixture were used to evaluate the attenuation of the overdriven detonation wave in the DDT process. Next, experiments were performed wherein a propane/oxygen mixture was separated from a propane/air mixture by a thin diaphragm to observe the transmission of an overdriven detonation wave. Based on the characteristic relations, a simple wave intersection model was used to calculate the state of the transmitted detonation wave. The results showed that a rarefaction effect must be included to ensure that there is no overestimate of the post-transmission wave properties when the incident detonation wave is overdriven. The strength of the incident overdriven detonation wave plays an important role in the wave transmission process. The experimental results showed that a transmitted overdriven detonation wave occurs instantaneously with a strong incident overdriven detonation wave. The near-CJ state of the incident wave leads to a transmitted shock wave, and then the transition to the overdriven detonation wave occurs downstream. The attenuation process for the overdriven detonation wave decaying to a near-CJ state occurs in all tests. After the attenuation process, an unstable detonation wave was observed in most tests. This may be attributed to the increase in the cell width in the attenuation process that exceeds the detonability cell width limit. (author)

  4. First-principles study of band gap engineering via oxygen vacancy doping in perovskite ABB'O? solid solutions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Qi, Tingting; Curnan, Matthew T.; Kim, Seungchul; Bennett, Joseph W.; Grinberg, Ilya; Rappe, Andrew M.

    2011-12-01T23:59:59.000Z

    Oxygen vacancies in perovskite oxide solid solutions are fundamentally interesting and technologically important. However, experimental characterization of the vacancy locations and their impact on electronic structure is challenging. We have carried out first-principles calculations on two Zr-modified solid solutions, Pb(Zn1/3Nb2/3)O? and Pb(Mg1/3Nb2/3)O?, in which vacancies are present. We find that the vacancies are more likely to reside between low-valent cation-cation pairs than high-valent cation-cation pairs. Based on the analysis of our results, we formulate guidelines that can be used to predict the location of oxygen vacancies in perovskite solid solutions. Our results show that vacancies can have a significant impactmore »on both the conduction and valence band energies, in some cases lowering the band gap by ?0.5 eV. The effects of vacancies on the electronic band structure can be understood within the framework of crystal field theory.« less

  5. The Quest for the Heaviest Uranium Isotope

    E-Print Network [OSTI]

    S. Schramm; D. Gridnev; D. V. Tarasov; V. N. Tarasov; W. Greiner

    2012-01-17T23:59:59.000Z

    We study Uranium isotopes and surrounding elements at very large neutron number excess. Relativistic mean field and Skyrme-type approaches with different parametrizations are used in the study. Most models show clear indications for isotopes that are stable with respect to neutron emission far beyond N=184 up to the range of around N=258.

  6. Regional groundwater flow paths in Trans-Pecos, Texas inferred from oxygen,

    E-Print Network [OSTI]

    Banner, Jay L.

    isotopes Matthew M. Uliana a,*, Jay L. Banner b , John M. Sharp Jr. b a Department of Earth and hydrogen, oxygen, and strontium isotopes. dD and d18 O values fall close to the global meteoric water line in the alluvial fill at the upgradient end of the flow system. ª 2006 Elsevier B.V. All rights reserved. 0022

  7. Hydrogen isotope fractionation during lipid biosynthesis by Haloarcula marismortui

    E-Print Network [OSTI]

    Hydrogen isotope fractionation during lipid biosynthesis by Haloarcula marismortui Sitindra S studied the controls on the fractionation of hydrogen isotopes during lipid biosynthesis by Haloarcula marismortui, a halophilic archaea, in pure culture experiments by varying organic substrate, the hydrogen

  8. Delayed neutron measurements from fast fission of actinide waste isotopes

    E-Print Network [OSTI]

    Charlton, William S.

    1997-01-01T23:59:59.000Z

    A study was performed to determine the delayed neutron emission properties from fast fission of several actinide waste isotopes. The specific isotopes evaluated were U-235, Np-237, and Am-243. A calculational technique based on the microscopic...

  9. Isotopic studies of sources of uranium in sediments of the Ashtabula River, Ohio, U.S.A.

    SciTech Connect (OSTI)

    Ketterer, M.E.; Wetzel, W.C.; Layman, R.R.; Matisoff, G.; Bonniwell, E.C.

    2000-03-15T23:59:59.000Z

    Uranium contamination of anthropogenic origin has been identified in unconsolidated sediment of a 1.5 km portion of the Ashtabula River near its confluence with Lake Erie. Uranium concentrations as high as 188 {mu}g/g dry sediment are present. A small tributary of the Ashtabula River, Fields Brook, is the apparent point of origin of the uranium in the Ashtabula River sediments. {sup 137}Cs dating of a sediment core indicates that the U contamination occurred during the post-1964 time frame. The horizons of elevated U concentration also exhibit > 10x elevations in Zr, Nb, Hf, Ta, and W. {sup 238}U/{sup 235}U isotopic ratios indicate that the uranium is largely but not exclusively of natural composition. Distinct horizons of slightly {sup 235}U-depleted ({sup 238}U/{sup 235}U > 137.88) and slightly {sup 235}U-enriched ({sup 238}U/{sup 235}U < 137.88) uranium are also present. {sup 210}Pb activities and {sup 232}Th/{sup 230}Th isotopic measurements indicate that a significant portion of the uranium contains {sup 238}U daughters in approximate secular equilibrium. It is inferred that at least two distinct sources of anthropogenic U contamination exist: (a) discharges from the processing of enriched and depleted U metal by a DOE contractor facility and (B) U-bearing wastes from the production of TiO{sub 2} from limonite and associated minerals. These isotopic methodologies are potentially useful in settings where releases of nonnatural {sup 238}U/{sup 235}U composition materials and/or naturally occurring radioactive material (NORM) have taken place.

  10. Studies on the room temperature growth of nanoanatase phase TiO{sub 2} thin films by pulsed dc magnetron with oxygen as sputter gas

    SciTech Connect (OSTI)

    Karuppasamy, A.; Subrahmanyam, A. [Semiconductor Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2007-03-15T23:59:59.000Z

    The anatase phase titanium dioxide (TiO{sub 2}) thin films were deposited at room temperature by pulsed dc magnetron sputtering using pure oxygen as sputter gas. The structural, optical, electrical, and electrochromic properties of the films have been studied as a function of oxygen pressure in the chamber. The x-ray diffraction results indicate that the films grown above 4.5x10{sup -2} mbar are nanocrystalline (grain size of 28-43 nm) with anatase phase. The films deposited at the chamber pressure of 7.2x10{sup -2} mbar are found to be highly crystalline with a direct optical band gap of 3.40 eV, refractive index of 2.54 (at {lambda}=400 nm), and work function of 4.77 eV (determined by the Kelvin probe measurements). From the optical emission spectra of the plasma and transport of ions in matter calculations, we find that the crystallization of TiO{sub 2} at room temperature is due to the impingement of electrons and ions on the growing films. Particularly, the negative oxygen ions reflected from the target by 'negative ion effects' and the enhanced density of TiO, TiO{sup +}, TiO{sub 2}{sup +}, and O{sup 2+} particles in the plasma are found to improve the crystallization even at a relatively low temperature. From an application point of view, the film grown at 7.2x10{sup -2} mbar was studied for its electrochromic properties by protonic intercalation. It showed good electrochromic behavior with an optical modulation of {approx}45%, coloration efficiency of 14.7 cm{sup 2} C{sup -1}, and switching time (t{sub c}) of 50 s for a 2x2 cm{sup 2} device at {lambda}=633 nm.

  11. Soil water utilization by herbaceous species of the southern Great Plains: evidence from isotopically labeled water

    E-Print Network [OSTI]

    Yoder, Carolyn Kay

    1993-01-01T23:59:59.000Z

    Understanding spatial and temporal patterns of soil water utilization by plants has broad implications for physiological, ecological, and hydrological processes. Water labeled with the stable isotopes deuterium ('H) or oxygen-18 ("'O) was injected...

  12. Effect of continuous positive airway pressure versus supplemental oxygen on sleep quality in obstructive sleep apnea: A placebo-CPAP-controlled study

    E-Print Network [OSTI]

    Loredo, J S; Ancoli-Israel, S; Kim, E J; Lim, W J; Dimsdale, J E

    2006-01-01T23:59:59.000Z

    generator, CPAP mask and tubing, heated humidifier (Fisher and Pykel HC100, Aukland New Zealand), and oxygen

  13. Assumptions and Criteria for Performing a Feasability Study of the Conversion of the High Flux Isotope Reactor Core to Use Low-Enriched Uranium Fuel

    SciTech Connect (OSTI)

    Primm, R.T., III; Ellis, R.J.; Gehin, J.C.; Moses, D.L.; Binder, J.L.; Xoubi, N. (U. of Cincinnati)

    2006-02-01T23:59:59.000Z

    A computational study will be initiated during fiscal year 2006 to examine the feasibility of converting the High Flux Isotope Reactor from highly enriched uranium fuel to low-enriched uranium. The study will be limited to steady-state, nominal operation, reactor physics and thermal-hydraulic analyses of a uranium-molybdenum alloy that would be substituted for the current fuel powder--U{sub 3}O{sub 8} mixed with aluminum. The purposes of this document are to (1) define the scope of studies to be conducted, (2) define the methodologies to be used to conduct the studies, (3) define the assumptions that serve as input to the methodologies, (4) provide an efficient means for communication with the Department of Energy and American research reactor operators, and (5) expedite review and commentary by those parties.

  14. Oxygen Transport Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay

    2008-08-30T23:59:59.000Z

    The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the small polaron conduction mechanism. Scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) were used to develop strategies to detect and characterize vacancy creation, dopant segregations and defect association in the oxygen conducting membrane material. The pO{sub 2} and temperature dependence of the conductivity, non-stoichiometry and thermal-expansion behavior of compositions with increasing complexity of substitution on the perovskite A and B sites were studied. Studies with the perovskite structure show anomalous behavior at low oxygen partial pressures (<10{sup -5} atm). The anomalies are due to non-equilibrium effects and can be avoided by using very strict criteria for the attainment of equilibrium. The slowness of the oxygen equilibration kinetics arises from two different mechanisms. In the first, a two phase region occurs between an oxygen vacancy ordered phase such as brownmillerite SrFeO{sub 2.5} and perovskite SrFeO{sub 3-x}. The slow kinetics is associated with crossing the two phase region. The width of the miscibility gap decreases with increasing temperature and consequently the effect is less pronounced at higher temperature. The preferred kinetic pathway to reduction of perovskite ferrites when the vacancy concentration corresponds to the formation of significant concentrations of Fe{sup 2+} is via the formation of a Ruddlesden-Popper (RP) phases as clearly observed in the case of La{sub 0.5}Sr{sub 0.5}FeO{sub 3-x} where LaSrFeO{sub 4} is found together with Fe. In more complex compositions, such as LSFTO, iron or iron rich phases are observed locally with no evidence for the presence of discrete RP phase. Fracture strength of tubular perovskite membranes was determined in air and in reducing atmospheric conditions. The strength of the membrane decreased with temperature and severity of reducing conditions although the strength distribution (Weibull parameter, m) was relatively unaltered. Surface and volume dominated the fracture origins and the overall fracture was purely transgranular. The dual phas

  15. Covalency in Metal-Oxygen Multiple Bonds Evaluated Using Oxygen...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Multiple Bonds Evaluated Using Oxygen K-edge Spectroscopy and Electronic Structure Theory . Covalency in Metal-Oxygen Multiple Bonds Evaluated Using Oxygen K-edge Spectroscopy...

  16. Investigation of the electrocatalysis for oxygen reduction reaction by Pt and binary Pt alloys: an XRD, XAS and electrochemical study

    SciTech Connect (OSTI)

    Mukerjee, S.; McBreen, J. [Brookhaven National Lab., Upton, NY (United States); Srinivasan, S. [Texas A and M Univ., College Station, TX (United States). Texas Engineering Experiment Station

    1995-12-31T23:59:59.000Z

    Electrocatalysis for the oxygen reduction reaction (ORR) on five binary Pt alloy electrocatalysts (PtCr/C, PtMn/C, PtFe/C, PtCo/C and PtNi/C) supported on carbon have been investigated. The electrochemical characteristics for ORR in a proton conducting fuel cell environment has been correlated with the electronic and structural parameters determined under in situ conditions using XANES and EXAFS technique respectively. Results indicate that all the alloys possess higher Pt 5d band vacancies as compared to Pt/C. There is also evidence of lattice contraction in the alloys (supported by XRD results). Further, the Pt/C shows increase in Pt 5 d band vacancies during potential transitions from 0.54 to 0.84 V vs. RHE, which has been ration@ on the basis of OH type adsorption. In contrast to this, the alloys do not exhibit such an enhancement. Detailed EXAFS analysis supports the presence of OH species on Pt/C and its relative absence in the alloys. Correlation of the electrochemical results with bond distances and d-band vacancies show a volcano type behavior with the PtCr/C on top of the curve.

  17. The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis

    E-Print Network [OSTI]

    photosynthesis Robert E. Kopp*, Joseph L. Kirschvink, Isaac A. Hilburn, and Cody Z. Nash Division of Geological biomarker, trace element, and isotopic evidence have been used to claim that oxygenic photosynthesis evolved phases. First, oxygenic photosynthesis evolved and brought into the world locally oxic environments

  18. The structure of molten CaSiO3: A neutron diffraction isotope substitution and aerodynamic levitation study.

    SciTech Connect (OSTI)

    Skinner, Lawrie [State University of New York, Stony Brook; Benmore, Chris J [Argonne National Laboratory (ANL); Weber, Richard [Argonne National Laboratory (ANL); Santodonato, Louis J [ORNL; Tumber, Sonia [Materials Development, Inc., Evanston, IL; Neuefeind, Joerg C [ORNL; Lazareva, Lena [State University of New York, Stony Brook; Du, Jincheng [University of North Texas; Parise, John B [Stony Brook University (SUNY)

    2012-01-01T23:59:59.000Z

    We have performed neutron diffraction isotopic substitution experiments on aerodynamically levitated droplets of CaSiO3, to directly extract intermediate and local structural information on the Ca environment. The results show a substantial broadening of the Ca-O peak in the pair distribution function of the melt compared to the glass, which comprises primarily of 6- and 7-fold coordinated Ca-polyhedra. The broadening can be explained by a re-distribution of Ca-O bond lengths, especially towards longer distances in the liquid. The first order neutron difference function provides a rigorous test of recent molecular dynamics simulations and supports the model of the presence of short chains or channels of edge shared Ca-octahedra in the liquid state. It is suggested that the polymerization of Ca-polyhedra is responsible for the fragile viscosity behavior of the melt and the glass forming ability in CaSiO3.

  19. Study of optical properties of asymmetric bipolar pulse DC magnetron sputtered Ta{sub 2}O{sub 5} thin film as a function of oxygen content in deposition ambient

    SciTech Connect (OSTI)

    Haque, S. Maidul, E-mail: skmaidulhaque@gmail.com; Shinde, D. D., E-mail: skmaidulhaque@gmail.com; Misal, J. S., E-mail: skmaidulhaque@gmail.com [Photonics and Nano-technology Section, Atomic and Molecular Physics Division, BARC, Visakhapatnam-530012 (India); Bhattacharyya, D.; Sahoo, N. K. [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai - 400085 (India)

    2014-04-24T23:59:59.000Z

    Tantalum penta-oxide thin films have been deposited by reactive sputtering technique using asymmetric bipolar pulsed DC source at various oxygen percentage viz. 0 to 50 %. The optical properties of the films have been studied by spectroscopic ellipsometry measurements. It has been observed that compact films with low void fraction, high refractive index and band gap can be obtained by the above technique with oxygen percentage in the range of 30–40%. The films deposited with zero or very low oxygen content have high deposition rate and yield metal rich films with large voids, defects, low band gap and high refractive index. Similarly films deposited with >40% oxygen content again contain voids and defects due to the presence of large amount of gas molecules in the sputtering ambient.

  20. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; T. Nithyanantham

    2006-12-31T23:59:59.000Z

    Ti doping on La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (LSF) tends to increase the oxygen equilibration kinetics of LSF in lower oxygen activity environment because of the high valence state of Ti. However, the addition of Ti decreases the total conductivity because the acceptor ([Sr{prime}{sub La}]) is compensated by the donor ([Ti{sub Fe}{sup {sm_bullet}}]) which decreases the carrier concentration. The properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 1-x}Ti{sub x}O{sub 3-{delta}} (LSFT, x = 0.45) have been experimentally and theoretically investigated to elucidate (1) the dependence of oxygen occupancy and electrochemical properties on temperature and oxygen activity by thermogravimetric analysis (TGA) and (2) the electrical conductivity and carrier concentration by Seebeck coefficient and electrical measurements. In the present study, dual phase (La{sub 0.2}Sr{sub 0.8}Fe{sub 0.6}Ti{sub 0.4}O{sub 3-{delta}}/Ce{sub 0.9}Gd{sub 0.1}O{sub 2-{delta}}) membranes have been evaluated for structural properties such as hardness, fracture toughness and flexural strength. The effect of high temperature and slightly reducing atmosphere on the structural properties of the membranes was studied. The flexural strength of the membrane decreases upon exposure to slightly reducing conditions at 1000 C. The as-received and post-fractured membranes were characterized using XRD, SEM and TG-DTA to understand the fracture mechanisms. Changes in structural properties of the composite were sought to be correlated with the physiochemical features of the two-phases. We have reviewed the electrical conductivity data and stoichiometry data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} some of which was reported previously. Electrical conductivity data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCrF) were obtained in the temperature range, 752 {approx} 1055 C and in the pO{sub 2} range, 10{sup -18} {approx} 0.5 atm. The slope of the plot of log {sigma} vs. log pO{sub 2} is {approx} 1/5 in the p-type region, pO{sub 2} = 10{sup -5} {approx} 10{sup -1} atm. The pO{sub 2} at which the p-n transition is observed increases with increasing temperature. The activation energy for ionic conduction was estimated to be 0.86 eV from an Arrhenius plot of the minimum conductivity vs. reciprocal temperature. At temperatures below 940 C, a plateau in the conductivity isotherm suggests the presence of a two-phase region. Most likely, phase separation occurs to form a mixture of a perovskite phase and an oxygen vacancy ordered phase related to brownmillerite. Additional data for the oxygen non stoichiometry are presented.

  1. Oxygen as a site specific structural probe in neutron diffraction

    SciTech Connect (OSTI)

    Neuefeind, Joerg C [ORNL; Simonson, J Michael {Mike} [ORNL; Salmon, Phil [University of Bath; Zeidler, Anita [University of Bath; Fischer, Henry E [Institut Laue-Langevin (ILL); Rauch, Helmut [E141 Atominstitut der & #xD6; sterreichischen Universit& #xE4; ten,; Markland, Thomas [Columbia University; Lemmel, Hartmut [Technical University Vienna

    2011-01-01T23:59:59.000Z

    Oxygen is a ubiquitous element, playing an essential role in most scientific and technological disciplines, and is often incorporated within a structurally disordered material where examples include molten silicates in planetary science, glasses used for lasers and optical communication, and water in biological processes. Establishing the structure of a liquid or glassy oxide and thereby its relation to the functional properties of a material is not, however, a trivial task owing to the complexity associated with atomic disorder. Here we approach this challenge by measuring the bound coherent neutron scattering lengths of the oxygen isotopes with the sensitive technique of neutron interferometry. We find that there is a small but finite contrast of 0.204(6) fm between the scattering lengths of the isotope 18O and oxygen of natural isotopic abundance natO, contrary to tables of recommended values. This has enabled us to investigate the structure of both light and heavy water by exploiting, for the first time, the method of oxygen isotope substitution in neutron diffraction, thus circumventing many of the significant problems associated with more traditional methods in which hydrogen is substituted by deuterium. We find a difference of ~0.5% between the O-H and O-D intra-molecular bond distances which is much smaller than recent estimates based on diffraction data and is found to be in excellent agreement with path integral molecular dynamics simulations made with a flexible polarisable water model. Our results demonstrate the potential for using oxygen isotope substitution as a powerful and effective site specific probe in a plethora of materials, of pertinence as instrumentation at next generation neutron sources comes online

  2. Oxygen partial pressure sensor

    DOE Patents [OSTI]

    Dees, D.W.

    1994-09-06T23:59:59.000Z

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.

  3. Active Oxygen Vacancy Site for Methanol Synthesis from CO2 Hydrogenation on In2O3(110): A DFT Study

    SciTech Connect (OSTI)

    Ye, Jingyun; Liu, Changjun; Mei, Donghai; Ge, Qingfeng

    2013-06-03T23:59:59.000Z

    Methanol synthesis from CO2 hydrogenation on the defective In2O3(110) surface with surface oxygen vacancies has been investigated using periodic density functional theory calculations. The relative stabilities of six possible surface oxygen vacancies numbered from Ov1 to Ov6 on the perfect In2O3(110) surface were examined. The calculated oxygen vacancy formation energies show that the D1 surface with the Ov1 defective site is the most thermodynamically favorable while the D4 surface with the Ov4 defective site is the least stable. Two different methanol synthesis routes from CO2 hydrogenation over both D1 and D4 surfaces were studied and the D4 surface was found to be more favorable for CO2 activation and hydrogenation. On the D4 surface, one of the O atoms of the CO2 molecule fills in the Ov4 site upon adsorption. Hydrogenation of CO2 to HCOO on the D4 surface is both thermodynamically and kinetically favorable. Further hydrogenation of HCOO involves both forming the C-H bond and breaking the C-O bond, resulting in H2CO and hydroxyl. The HCOO hydrogenation is slightly endothermic with an activation barrier of 0.57 eV. A high barrier of 1.14 eV for the hydrogenation of H2CO to H3CO indicates that this step is the rate-limiting step in the methanol synthesis on the defective In2O3(110) surface. We gratefully acknowledge the supports from the National Natural Science Foundation of China (#20990223) and from US Department of Energy, Basic Energy Science program (DE-FG02-05ER46231). D. Mei was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. The computations were performed in part using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at Pacific Northwest National Laboratory in Richland, Washington. PNNL is a multiprogram national laboratory operated for DOE by Battelle.

  4. Hyperbaric Oxygen Treatment in Radiation-Induced Cystitis and Proctitis: A Prospective Cohort Study on Patient-Perceived Quality of Recovery

    SciTech Connect (OSTI)

    Oscarsson, Nicklas, E-mail: nicklas.oscarsson@vgregion.se [Department of Anaesthesiology and Intensive Care Medicine, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg (Sweden); Arnell, Per [Department of Anaesthesiology and Intensive Care Medicine, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg (Sweden); Lodding, Pär [Department of Urology, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg (Sweden); Ricksten, Sven-Erik; Seeman-Lodding, Heléne [Department of Anaesthesiology and Intensive Care Medicine, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg (Sweden)

    2013-11-15T23:59:59.000Z

    Purpose: In this prospective cohort study, the effects of hyperbaric oxygen treatment (HBOT) were evaluated concerning patient-perceived symptoms of late radiation-induced cystitis and proctitis secondary to radiation therapy for pelvic cancer. Methods and Materials: Thirty-nine patients, 35 men and 4 women with a mean age of 71 (range, 35-84) years were included after informed consent and institutional ethics approval. They had all been treated with radiation therapy for prostate (n=34), cervix (n=2), or rectal (n=3) cancer using external beam radiation at a dose of 25 to 75 Gy. Patients with hematuria requiring blood transfusion were excluded. The HBOT was delivered with 100% oxygen for 90 minutes at 2.0 to 2.4 atmospheres (ATA). Mean number of treatments was 36 (28-40). Symptoms were prospectively assessed using the Expanded Prostate Index Composite score before, during, and 6 to 12 months after HBOT. Results: The HBOT was successfully conducted, and symptoms were alleviated in 76% for patients with radiation cystitis, 89% for patients with radiation proctitis, and 88% of patients with combined cystitis and proctitis. Symptom reduction was demonstrated by an increased Expanded Prostate Index Composite score in the urinary domain from 50 ± 16 to 66 ± 20 after treatment (P<.001) and in the bowel domain from 48 ± 18 to 68 ± 18 after treatment (P<.001). For 31% of the patients with cystitis and 22% with proctitis, there were only trivial symptoms after HBOT. The improvement was sustained at follow-up in both domains 6 to 12 months after HBOT. No severe side effects were observed related to HBOT, and treatment compliance was high. Conclusions: HBOT can be an effective and safe treatment modality for late radiation therapy-induced soft tissue injuries in the pelvic region.

  5. Integrated turbomachine oxygen plant

    SciTech Connect (OSTI)

    Anand, Ashok Kumar; DePuy, Richard Anthony; Muthaiah, Veerappan

    2014-06-17T23:59:59.000Z

    An integrated turbomachine oxygen plant includes a turbomachine and an air separation unit. One or more compressor pathways flow compressed air from a compressor through one or more of a combustor and a turbine expander to cool the combustor and/or the turbine expander. An air separation unit is operably connected to the one or more compressor pathways and is configured to separate the compressed air into oxygen and oxygen-depleted air. A method of air separation in an integrated turbomachine oxygen plant includes compressing a flow of air in a compressor of a turbomachine. The compressed flow of air is flowed through one or more of a combustor and a turbine expander of the turbomachine to cool the combustor and/or the turbine expander. The compressed flow of air is directed to an air separation unit and is separated into oxygen and oxygen-depleted air.

  6. Oxygen ion conducting materials

    DOE Patents [OSTI]

    Carter, J. David; Wang, Xiaoping; Vaughey, John; Krumpelt, Michael

    2004-11-23T23:59:59.000Z

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  7. Oxygen ion conducting materials

    DOE Patents [OSTI]

    Vaughey, John; Krumpelt, Michael; Wang, Xiaoping; Carter, J. David

    2005-07-12T23:59:59.000Z

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  8. Oxygen ion conducting materials

    DOE Patents [OSTI]

    Vaughey, John (Elmhurst, IL); Krumpelt, Michael (Naperville, IL); Wang, Xiaoping (Downers Grove, IL); Carter, J. David (Bolingbrook, IL)

    2003-01-01T23:59:59.000Z

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  9. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-05-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C. It was found that space group of R3c yielded a better refinement than a cubic structure of Pm3m. Oxygen occupancy was nearly 3 in the region from room temperature to 700 C, above which the occupancy decreased due to oxygen loss. Dense OTM bars provided by Praxair were loaded to fracture at varying stress rates. Studies were done at room temperature in air and at 1000 C in a specified environment to evaluate slow crack growth behavior. The X-Ray data and fracture mechanisms points to non-equilibrium decomposition of the LSFCO OTM membrane. The non-equilibrium conditions could probably be due to the nature of the applied stress field (stressing rates) and leads to transition in crystal structures and increased kinetics of decomposition. The formations of a Brownmillerite or Sr2Fe2O5 type structures, which are orthorhombic are attributed to the ordering of oxygen vacancies. The cubic to orthorhombic transitions leads to 2.6% increase in strains and thus residual stresses generated could influence the fracture behavior of the OTM membrane. Continued investigations on the thermodynamic properties (stability and phase-separation behavior) and total conductivity of prototype membrane materials were carried out. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previously characterization, stoichiometry and conductivity measurements for samples of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were reported. In this report, measurements of the chemical and thermal expansion as a function of temperature and p{sub O2} are described.

  10. Continuous surface ocean measurements of dissolved oxygen isotopes

    E-Print Network [OSTI]

    Rafelski, Lauren Elmegreen

    2012-01-01T23:59:59.000Z

    through a 130 micron Amiad strainer that was modified to beP T 40 L min Flowmeter Strainer 5.7 L min 100 mL min Bagfiltered with a 130 micron strainer. This water goes into a

  11. Oxygen Isotope Evidence For Past And Present Hydrothermal Regimes...

    Open Energy Info (EERE)

    to exist beneath the western moat, perhaps beneath Mammoth Mountain. Authors Brian M. Smith and Gene A. Suemnicht Published Journal Journal of Volcanology and Geothermal...

  12. Continuous surface ocean measurements of dissolved oxygen isotopes

    E-Print Network [OSTI]

    Rafelski, Lauren Elmegreen

    2012-01-01T23:59:59.000Z

    Figure 6.2: Fossil fuel emissions perof Carbon Dioxide from Fossil Fuels, editors W. P. Elliott,Carbon dioxide emissions from fossil fuels: A procedure for

  13. OXYGEN ISOTOPIC RATIOS IN COOL R CORONAE BOREALIS STARS

    SciTech Connect (OSTI)

    Garcia-Hernandez, D. A. [Instituto de Astrofisica de Canarias (IAC), C/Via Lactea s/n, 38200 La Laguna, Tenerife (Spain); Lambert, David L. [W. J. McDonald Observatory, University of Texas at Austin. 1 University Station, C1400. Austin, TX 78712-0259 (United States); Rao, N. Kameswara [Indian Institute of Astrophysics, Bangalore 560 034 (India); Hinkle, Ken H. [National Optical Astronomy Observatory (NOAO), Tucson, AZ 85726 (United States); Eriksson, Kjell, E-mail: agarcia@iac.e, E-mail: dll@astro.as.utexas.ed, E-mail: nkrao@iiap.res.i, E-mail: hinkle@noao.ed, E-mail: Kjell.Eriksson@astro.uu.s [Department of Physics and Astronomy, Uppsala University, Box 515, 75120 Uppsala (Sweden)

    2010-05-01T23:59:59.000Z

    We investigate the relationship between R Coronae Borealis (RCB) stars and hydrogen-deficient carbon (HdC) stars by measuring precise {sup 16}O/{sup 18}O ratios for five cool RCB stars. The {sup 16}O/{sup 18}O ratios are derived by spectrum synthesis from high-resolution (R {approx} 50, 000) K-band spectra. Lower limits to the {sup 16}O/{sup 17}O and {sup 14}N/{sup 15}N ratios as well as Na and S abundances (when possible) are also given. RCB stars in our sample generally display less {sup 18}O than HdC stars-the derived {sup 16}O/{sup 18}O ratios range from 3 to 20. The only exception is the RCB star WX CrA, which seems to be an HdC-like star with {sup 16}O/{sup 18}O = 0.3. Our result of a higher {sup 16}O/{sup 18}O ratio for the RCB stars must be accounted for by a theory of the formation and evolution of HdC and RCB stars. We speculate that a late dredge-up of products of He burning, principally {sup 12}C and {sup 16}O, may convert an {sup 18}O-rich HdC star into an {sup 18}O-poor RCB star as the H-deficient star begins its final evolution from a cool supergiant to the top of the white dwarf cooling track.

  14. Geothermal Reservoir Temperatures Estimated from the Oxygen Isotope

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation, search OpenEI Reference LibraryAdd to libraryOpenCX TypeProvince, Northern

  15. Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,OwlsMichigan:Ohio:Drill

  16. Geothermal reservoir temperatures estimated from the oxygen isotope

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are8COaBulkTransmissionSitingProcess.pdf Jump1946865°,Park,2005)EnergyAmatitlan Geothermal Areagreenhousecompositions

  17. Mechanisms of deformation in gum metal TNTZ-O and TNTZ titanium alloys: A comparative study on the oxygen influence

    E-Print Network [OSTI]

    Boyer, Edmond

    of these properties are obtained after cold working. These properties make this alloy an excellent candidate also been shown by in situ X-ray diffraction tensile tests [13] and [14]. This transformationMechanisms of deformation in gum metal TNTZ-O and TNTZ titanium alloys: A comparative study

  18. Hybrid isotope separation scheme

    DOE Patents [OSTI]

    Maya, J.

    1991-06-18T23:59:59.000Z

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus. 2 figures.

  19. Hybrid isotope separation scheme

    DOE Patents [OSTI]

    Maya, Jakob (Brookline, MA)

    1991-01-01T23:59:59.000Z

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus.

  20. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; W.B. Yelon; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-02-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and initial studies on newer composition of Ti doped LSF. Dense OTM bars provided by Praxair were loaded to fracture at varying stress rates. Studies were done at room temperature in air and at 1000 C in a specified environment to evaluate slow crack growth behavior. In addition, studies were also begun to obtain reliable estimates of fracture toughness and stable crack growth in specific environments. Newer composition of Ti doped LSF membranes were characterized by neutron diffraction analysis. Quench studies indicated an apparent correlation between the unit cell volume and oxygen occupancy. The studies however, indicated an anomaly of increasing Fe/Ti ratio with change in heat treatment. Ti doped LSF was also characterized for stoichiometry as a function of temp and pO{sub 2}. The non stoichiometry parameter {delta} was observed to increase almost linearly on lowering pO{sub 2} until a ideal stoichiometric composition of {delta} = 0.175 was approached.

  1. Stable isotope enrichment

    ScienceCinema (OSTI)

    Egle, Brian

    2014-07-15T23:59:59.000Z

    Brian Egle is working to increase the nation's capacity to produce stable isotopes for use including medicine, industry and national security.

  2. Isotopically controlled semiconductors

    E-Print Network [OSTI]

    Haller, E.E.

    2004-01-01T23:59:59.000Z

    and phonons in semiconductors,” J. Non-Cryst. Solids 141 (LVM) Spectroscopy of Semiconductors,” Mat. Res. Soc. Symp.Isotopically Engineered Semiconductors – New Media for the

  3. Stable isotope enrichment

    SciTech Connect (OSTI)

    Egle, Brian

    2014-07-14T23:59:59.000Z

    Brian Egle is working to increase the nation's capacity to produce stable isotopes for use including medicine, industry and national security.

  4. Microfluidic advantage : novel techniques for protein folding and oxygen control in cell cultures

    E-Print Network [OSTI]

    Polinkovsky, Mark E.; Polinkovsky, Mark E.

    2012-01-01T23:59:59.000Z

    Novel Techniques for Protein Folding and Oxygen Control inTemperature Jump System to Study Fast Protein FoldingNovel Techniques for Protein Folding and Oxygen Control in

  5. Discovery of the Tungsten Isotopes

    E-Print Network [OSTI]

    A. Fritsch; J. Q. Ginepro; M. Heim; A. Schuh; A. Shore; M. Thoennessen

    2009-03-25T23:59:59.000Z

    Thirty-five tungsten isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  6. Discovery of the Titanium Isotopes

    E-Print Network [OSTI]

    D. Meierfrankenfeld; M. Thoennessen

    2010-09-08T23:59:59.000Z

    Twentyfive titanium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  7. Discovery of the Tin Isotopes

    E-Print Network [OSTI]

    S. Amos; M. Thoennessen

    2010-09-08T23:59:59.000Z

    Thirty-eight tin isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  8. Discovery of the tungsten isotopes

    SciTech Connect (OSTI)

    Fritsch, A.; Ginepro, J.Q.; Heim, M.; Schuh, A.; Shore, A. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Thoennessen, M. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)], E-mail: thoennessen@nscl.msu.edu

    2010-05-15T23:59:59.000Z

    Thirty-five tungsten isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  9. Discovery of the Tungsten Isotopes

    E-Print Network [OSTI]

    Fritsch, A; Heim, M; Schuh, A; Shore, A; Thoennessen, M

    2009-01-01T23:59:59.000Z

    Thirty-five tungsten isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  10. antimony isotopes: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1 Hartmut Bracht 258 Late Pleistocene C4 Plant Dominance and Summer Rainfall in the Southwestern United States from Isotopic Study of Herbivore Teeth Geosciences Websites Summary:...

  11. SELECTIVE REDUCTION OF NOX IN OXYGEN RICH ENVIRONMENTS WITH PLASMA-ASSISTED CATALYSIS: CATALYST DEVELOPMENT AND MECHANISTIC STUDIES

    SciTech Connect (OSTI)

    Peden, C; Barlow, S; Hoard, J; Kwak, J; *Balmer-Millar, M; *Panov, A; Schmieg, S; Szanyi, J; Tonkyn, R

    2003-08-24T23:59:59.000Z

    The control of NOx (NO and NO2) emissions from so-called ''lean-burn'' vehicle engines remains a challenge. In recent years, there have been a number of reports that show that a plasma device combined with a catalyst can reduce as high as 90% or more of NOx in simulated diesel and other ''lean-burn'' exhaust. In the case of propylene containing simulated diesel exhaust, the beneficial role of a plasma treatment is now thought to be due to oxidation of NO to NO2, and the formation of partially oxidized hydrocarbons that are more active for the catalytic reduction of NO2 than propylene. Thus, the overall system can be most usefully described as hydrocarbon selective catalytic reduction (SCR) enhanced by 'reforming' the exhaust with a non-thermal plasma (NTP) device. For plasma-enhanced catalysis, both zeolite- and alumina-based materials have shown high activity, albeit in somewhat different temperature ranges, when preceded by an NTP reactor. This paper will briefly describe our research efforts aimed at optimizing the catalyst materials for NTP-catalysis devices based, in part, on our continuing studies of the NTP- and catalytic-reaction mechanisms. Various alkali- and alkaline earth-cation-exchanged Y zeolites have been prepared, their material properties characterized, and they have been tested as catalytic materials for NOx reduction in laboratory NTP-catalysis reactors. Interestingly, NO2 formed in the plasma and not subsequently removed over these catalysts, will back-convert to NO, albeit to varying extents depending upon the nature of the cation. Besides this comparative reactivity, we will also discuss selected synthesis strategies for enhancing the performance of these zeolite-based catalyst materials. A particularly important result from our mechanistic studies is the observation that aldehydes, formed during the plasma treatment of simulated diesel exhaust, are the important species for the reduction of NOx to N2. Indeed, acetaldehyde has been found to be especially effective in the thermal reduction of both NO and NO2 over Ba- and Na-Y zeolite catalysts.

  12. Seasonal cycle of carbon dioxide and its isotopic composition in an urban atmosphere: Anthropogenic and biogenic effects

    E-Print Network [OSTI]

    Ehleringer, Jim

    and summer. The effects of gasoline combustion, natural gas combustion, and biogenic respiration of plants isotopic tracers. The calculations showed large contributions of natural gas combustion in the winter burning, and fossil fuel combustion impart carbon and oxygen isotope signals to the atmosphere that can

  13. REEVALUATION OF ISOTOPIC SCALE FOR CO2 IN NIES AND ITS RELATION WITH INTER-COMPARISON WORKS

    E-Print Network [OSTI]

    bottle during preservation. We tried several chemical treatments and heating of the glass bottles property; We found that the extraction by NIES glass vacuum line have little effect on isotope values. On the other hand oxygen isotope ratio in the sample was found to be modified by contact with water in a glass

  14. (Carbon isotope fractionation inplants)

    SciTech Connect (OSTI)

    O'Leary, M.H.

    1990-01-01T23:59:59.000Z

    The objectives of this research are: To develop a theoretical and experimental framework for understanding isotope fractionations in plants; and to develop methods for using this isotope fractionation for understanding the dynamics of CO{sub 2} fixation in plants. Progress is described.

  15. Laser isotope separation

    DOE Patents [OSTI]

    Robinson, C. Paul (Los Alamos, NM); Jensen, Reed J. (Los Alamos, NM); Cotter, Theodore P. (Munich, DE); Boyer, Keith (Los Alamos, NM); Greiner, Norman R. (Los Alamos, NM)

    1988-01-01T23:59:59.000Z

    A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium.

  16. Photochemical isotope separation

    DOE Patents [OSTI]

    Robinson, C. Paul (Los Alamos, NM); Jensen, Reed J. (Los Alamos, NM); Cotter, Theodore P. (Los Alamos, NM); Greiner, Norman R. (Los Alamos, NM); Boyer, Keith (Los Alamos, NM)

    1987-01-01T23:59:59.000Z

    A process for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium.

  17. Photochemical isotope separation

    DOE Patents [OSTI]

    Robinson, C.P.; Jensen, R.J.; Cotter, T.P.; Greiner, N.R.; Boyer, K.

    1987-04-28T23:59:59.000Z

    A process is described for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium. 8 figs.

  18. The Growth of Thin Epitaxial Copper Films on Ruthenium (0001)and Oxygen-Precovered Ruthenium (0001) as studied by x-rayphotoelectron diffraction. University of California, Davis, Department of Physics, Ph.D. Thesis

    SciTech Connect (OSTI)

    Ruebush, Scott Daniel

    1997-06-01T23:59:59.000Z

    In the first part of this dissertation, the variation of mean emitter depths with direction for core photoelectron emission from single crystals, including the effects of both isotropic inelastic scattering and single and multiple elastic scattering was theoretically studied. The mean emitter depth was found to vary by as much as ±30% with direction. In the second part of this dissertation, x-ray photoelectron diffraction (XPD) was used to study the structure and growth mechanisms of Cu films grown on a clean and an oxygen-precovered Ru(OOO1) surface. Experimental Cu 2p3/2 (Ekin = 556 eV) and Ru 3d (Ekin = 1205 eV) intensities were measured for Cu coverages from submonolayer up to several monolayer (ML) on the clean Ru(OOO1) surface. In addition, the O 1s (Ekin = 958 eV) intensity was measured for Cu grown on oxygen precovered Ru(OOO1). These XPD intensities have been analyzed using single scattering cluster (SSC) and multiple scattering cluster (MSC) models. The first Cu layer has been found to grow pseudomorphically on the Ru(OOO1) surface in agreement with prior studies of the Cu/Ru(OOO 1) system. Thus, the initial growth is layer-by-layer. For higher coverages, XPD shows that the short-range structure of the Cu films is fcc Cu(l 11), but with significant interlayer relaxation (compared to bulk Cu(l 11)) that persists up to {ge}8 ML. When oxygen is preadsorbed on the Ru(OOO1) surface before Cu film growth (possibly to act as a surfactant promoting smoother growth), XPD shows that the first ~3 ML of Cu grow as 3-D islands. In addition, XPD shows that, during Cu growth, all of the oxygen "floats" on the CU surface, in contrast to prior studies which found that 30% of the oxygen remains at the Cu/Ru intetiace. XPD also indicates that the oxygen is highly disordered on the Cu overlayer surface. In thicker layers with oxygen prsent, the Cu grows as Cu(l 11) with equal occupations of two possible domains rotated by 1800 from each other. In general, this work demonstrates the considerable usefulness of XPD in studying epitaxial overlayer growth with and without surfactants present.

  19. A strontium and neodymium isotopic study of Apollo 17 high-Ti mare basalts: Resolution of ages, evolution of magmas, and origins of source heterogeneities

    SciTech Connect (OSTI)

    Paces, J.B.; Neal, C.R.; Taylor, L.A. (Univ. of Tennessee, Knoxville (United States)); Nakai, Shun'ichi; Halliday, A.N.; Lee, D.C. (Univ. of Michigan, Ann Arbor (United States))

    1991-07-01T23:59:59.000Z

    A combined Sr and Nd isotopic study of 15 Apollo 17 high-Ti mare basalts was undertaken to investigate geochronological and compositional differences between previously identified magma types (A, B1, B2, and C). Whole-rock and mineral separates for one of the least-evolved Type B1 basalts, 70139, yield Sm-Nd and Rb-Sr isochron ages of 3.71 {plus minus} 0.12 Ga and 3.65 {plus minus} 0.07 Ga and a Rb-Sr isochron age of 3.67 {plus minus} 0.10 Ga. Although these two ages are non-resolvable by themselves, compilation of all available geochronological data allows resolution of Type A and B1/B2 ages at high levels of confidence (> 99%). The most reliably dated samples, classified according to their geochemical type, yield weighted average ages of 3.75 {plus minus} 0.02 Ga for Type A (N = 4) and 3.69 {plus minus} 0.02 Ga for Type B1/B2 (N = 3) basalts. Insufficient geochronological data are available to place the rare, Type C basalts within this stratigraphy. The authors propose that age differences correlate with geochemical magma type, and that early magmatism was dominated by eruption of Type A basalts while later activity was dominated by effusion of Type B1 and B2 basalts.

  20. High Selectivity Oxygen Delignification

    SciTech Connect (OSTI)

    Lucian A. Lucia

    2005-11-15T23:59:59.000Z

    Project Objective: The objectives of this project are as follows: (1) Examine the physical and chemical characteristics of a partner mill pre- and post-oxygen delignified pulp and compare them to lab generated oxygen delignified pulps; (2) Apply the chemical selectivity enhancement system to the partner pre-oxygen delignified pulps under mill conditions (with and without any predetermined amounts of carryover) to determine how efficiently viscosity is preserved, how well selectivity is enhanced, if strength is improved, measure any yield differences and/or bleachability differences; and (3) Initiate a mill scale oxygen delignification run using the selectivity enhancement agent, collect the mill data, analyze it, and propose any future plans for implementation.

  1. EMSL - oxygen-plasma

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    oxygen-plasma en Conversion of 1,2-Propylene Glycol on Rutile TiO2(110). http:www.emsl.pnl.govemslwebpublicationsconversion-12-propylene-glycol-rutile-tio2110

  2. Study of the Susceptibility of Oxygen-Free Phosphorous Doped Copper to Corrosion in Simulated Groundwater in the Presence of Chloride and Sulfide

    SciTech Connect (OSTI)

    Escobar, Ivan; Lamas, Claudia [Chilean Commission for Nuclear Energy, Amunategui No 95, Santiago, 834-0701 (Chile); Werme, Lars [Svensk Kaernbraenslehantering AB (SKB), Stockholm (Sweden)]|[Department of Physics, Uppsala University, Uppsala (Sweden); Oversby, Virginia [VMO Konsult, Stockholm (Sweden)

    2007-07-01T23:59:59.000Z

    Oxygen free high conductivity copper, doped with phosphorus (Cu OFP) has been chosen as the material for the fabrication of high level nuclear waste containers in Sweden. This material will be the corrosion barrier for spent fuel in the environment of a deep geological repository in granitic rock. The service life of this container is expected to exceed 1,000,000 years. During this time, which includes several glaciations, water of different compositions, including high concentration of chloride ions, will contact the copper surface. This work reports a study of the susceptibility of Cu OFP to corrosion when chloride ions are present, in deionized water (DW) and in synthetic groundwater (SGW). The techniques used were electrochemical methods such as corrosion potential evolution and Tafel curves. The system was studied with Electrochemical Impedance Spectroscopy (EIS). We also used as characterization techniques Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The main conclusions are that copper is more susceptible to corrosion at high chloride ion concentration. When the chloride concentration is low, it is possible to form copper chloride crystals, but at the highest concentration, copper chloride complexes are formed, leaving the copper surface without deposits. When the chloride concentration is low (<0.1 M) the corrosion process is mainly controlled by diffusion, while at higher concentrations (0.1 M to 1 M) corrosion is controlled by charge transfer processes. At low concentration of sulfide (<3 . 10{sup -5} M), copper corrosion in the presence of chloride is controlled by diffusional processes, while at higher concentrations corrosion is controlled by charge transfer processes. (authors)

  3. SNP in TXNRD2 Associated With Radiation-Induced Fibrosis: A Study of Genetic Variation in Reactive Oxygen Species Metabolism and Signaling

    SciTech Connect (OSTI)

    Edvardsen, Hege, E-mail: hege.edvardsen@rr-research.no [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway) [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway); K. G. Jebsen Breast cancer centre, Institute for Clinical Medicine, University of Oslo, Oslo (Norway); Landmark-Høyvik, Hege [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway) [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway); K. G. Jebsen Breast cancer centre, Institute for Clinical Medicine, University of Oslo, Oslo (Norway); Reinertsen, Kristin V. [National Resource Centre for Late Effects after Cancer Treatment, OUS Radiumhospitalet, Oslo (Norway)] [National Resource Centre for Late Effects after Cancer Treatment, OUS Radiumhospitalet, Oslo (Norway); Zhao, Xi [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway) [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway); K. G. Jebsen Breast cancer centre, Institute for Clinical Medicine, University of Oslo, Oslo (Norway); Grenaker-Alnæs, Grethe Irene; Nebdal, Daniel [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway)] [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway); Syvänen, Ann-Christine [Department of Medical Sciences, Uppsala University, Uppsala (Sweden)] [Department of Medical Sciences, Uppsala University, Uppsala (Sweden); Rødningen, Olaug [Department of Medical Genetics, OUS Ullevaal, Oslo (Norway)] [Department of Medical Genetics, OUS Ullevaal, Oslo (Norway); Alsner, Jan; Overgaard, Jens [Department of Experimental Clinical Oncology, Ahus University Hospital (Norway)] [Department of Experimental Clinical Oncology, Ahus University Hospital (Norway); Borresen-Dale, Anne-Lise [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway) [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway); K. G. Jebsen Breast cancer centre, Institute for Clinical Medicine, University of Oslo, Oslo (Norway); Fosså, Sophie D. [K. G. Jebsen Breast cancer centre, Institute for Clinical Medicine, University of Oslo, Oslo (Norway) [K. G. Jebsen Breast cancer centre, Institute for Clinical Medicine, University of Oslo, Oslo (Norway); National Resource Centre for Late Effects after Cancer Treatment, OUS Radiumhospitalet, Oslo (Norway); Kristensen, Vessela N. [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway) [Department of Genetics, Institute for Cancer Research, OUS Radiumhospitalet, Oslo (Norway); K. G. Jebsen Breast cancer centre, Institute for Clinical Medicine, University of Oslo, Oslo (Norway); Department of Clinical Molecular Biology (EpiGen), Division of Medicine, Ahus University Hospital (Norway)

    2013-07-15T23:59:59.000Z

    Purpose: The aim of the study was to identify noninvasive markers of treatment-induced side effects. Reactive oxygen species (ROS) are generated after irradiation, and genetic variation in genes related to ROS metabolism might influence the level of radiation-induced adverse effects (AEs). Methods and Materials: 92 breast cancer (BC) survivors previously treated with hypofractionated radiation therapy were assessed for the AEs subcutaneous atrophy and fibrosis, costal fractures, lung fibrosis, pleural thickening, and telangiectasias (median follow-up time 17.1 years). Single-nucleotide polymorphisms (SNPs) in 203 genes were analyzed for association to AE grade. SNPs associated with subcutaneous fibrosis were validated in an independent BC survivor material (n=283). The influence of the studied genetic variation on messenger ribonucleic acid (mRNA) expression level of 18 genes previously associated with fibrosis was assessed in fibroblast cell lines from BC patients. Results: Subcutaneous fibrosis and atrophy had the highest correlation (r=0.76) of all assessed AEs. The nonsynonymous SNP rs1139793 in TXNRD2 was associated with grade of subcutaneous fibrosis, the reference T-allele being more prevalent in the group experiencing severe levels of fibrosis. This was confirmed in another sample cohort of 283 BC survivors, and rs1139793 was found significantly associated with mRNA expression level of TXNRD2 in blood. Genetic variation in 24 ROS-related genes, including EGFR, CENPE, APEX1, and GSTP1, was associated with mRNA expression of 14 genes previously linked to fibrosis (P?.005). Conclusion: Development of subcutaneous fibrosis can be associated with genetic variation in the mitochondrial enzyme TXNRD2, critically involved in removal of ROS, and maintenance of the intracellular redox balance.

  4. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; N. Nagabhushana

    2003-08-07T23:59:59.000Z

    In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/ Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Existing facilities were modified for evaluation of environmental assisted slow crack growth and creep in flexural mode. Processing of perovskites of LSC, LSF and LSCF composition were continued for evaluation of mechanical properties as a function of environment. These studies in parallel to those on the LSFCO composition is expect to yield important information on questions such as the role of cation segregation and the stability of the perovskite structure on crack initiation vs. crack growth. Studies have been continued on the La{sub 1-x}Sr{sub x}FeO{sub 3-d} composition using neutron diffraction and TGA studies. A transition from p-type to n-type of conductor was observed at relative low pO{sub 2}, at which the majority carriers changed from the holes to electrons because of the valence state decreases in Fe due to the further loss of oxygen. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport. Data obtained at 850 C show that the stoichiometry in La{sub 0.2}Sr{sub 0.8}Fe{sub 0.8}Cr{sub 0.2}O{sub 3-x} vary from {approx}2.85 to 2.6 over the pressure range studied. From the stoichiometry a lower limit of 2.6 corresponding to the reduction of all Fe{sup 4+} to Fe{sup 3+} and no reduction of Cr{sup 3+} is expected.

  5. A calcium oxygen secondary battery

    SciTech Connect (OSTI)

    Pujare, N.U.; Semkow, K.W.; Sammells, A.F.

    1988-01-01T23:59:59.000Z

    The authors report preliminary work performed in their laboratory on a high-temperature electrochemically reversible calcium-oxygen cell. Following an analogous strategy to that recently discussed for the lithium-oxygen secondary system, this calcium-oxygen cell utilizes stabilized zirconia oxygen vacancy conducting solid electrolytes to achieve effective separation between half-cell reactions.

  6. High-purity, isotopically enriched bulk silicon

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    Russia. The stated isotope enrichments are summarized inenrichments >99% have been achieved for each isotope andthe enrichment is highest, are presented. isotope at. % nat.

  7. Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes

    E-Print Network [OSTI]

    Thomas R. Ayres; Claude Plymate; Christoph U. Keller

    2006-06-07T23:59:59.000Z

    A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum intensities and center-limb behavior constrained the temperature profile of the deep photosphere, while CO center-limb behavior defined the thermal structure at higher altitudes. The oxygen abundance was self consistently determined from weak CO absorptions. Our analysis was meant to complement recent studies based on 3-D convection models which, among other things, have revised the historical solar oxygen (and carbon) abundance downward by a factor of nearly two; although in fact our conclusions do not support such a revision. Based on various considerations, an oxygen abundance of 700+/-100 ppm (parts per million relative to hydrogen) is recommended; the large uncertainty reflects the model sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O, and 18O.

  8. Vibronic origin of sulfur mass-independent isotope effect in photoexcitation of SO[subscript 2] and the implications to the early earth's atmosphere

    E-Print Network [OSTI]

    Whitehill, Andrew Richard

    Signatures of mass-independent isotope fractionation (MIF) are found in the oxygen ([superscript 16]O, [superscript 17]O, [superscript 18]O) and sulfur ([superscript 32]S, [superscript 33]S, [superscript 34]S, [superscript ...

  9. active oxygen probe: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: I present here the results of the first principles studies of the adsorption energetics of the intermediates of the oxygen electro-reduction reaction (ORR)...

  10. Thickness Dependency of Thin Film Samaria Doped Ceria for Oxygen...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    High temperature oxygen sensors are widely used for exhaust gas monitoring in automobiles. This particular study explores the use of thin film single crystalline samaria...

  11. Rb-Sr and Sm-Nd isotopic study of the Glen Mountains layered complex: initiation of rifting within the southern Oklahoma aulacogen

    SciTech Connect (OSTI)

    Lambert, D.D.; Unruh, D.M.; Gilbert, M.C.

    1988-01-01T23:59:59.000Z

    Rb-Sr and Sm-Nd isotopic data for rocks and minerals of the Glen Mountains layered complex (GMLC), a midcontinent mafic layered intrusion in the Wichita Mountains of southwestern Oklahoma, constrain the time of initiation of rifting within the southern Oklahoma aulacogen and provide information on the chemistry of the early Paleozoic mantle. Four whole-rock samples define a Rb-Sr isochron corresponding to a maximum crystallization age of 577 +/- 165 Ma and an initial Sr isotopic composition of 0.70359 +/- 2. A three-point Sm-Nd mineral-whole-rock (internal) isochron for an anorthositic gabbro provides a crystallization age of 528 +/- 29 Ma. These data suggest that the GMLC was emplaced into the southern Oklahoma aulacogen during the initial phase of rifting along the southern margin of the North American craton in the early Paleozoic. This Sm-Nd internal isochron age is within analytical uncertainty of U-Pb zircon ages for granites and rhyolites from the Wichita Mountains; therefore, mafic and felsic magmatism may have been contemporaneous within the rift during the early stages of development. Hybrid rocks and composite dikes in the Wichita Mountains provide field evidence for contemporaneous mafic and felsic magmas. Initial Sr and Nd isotopic data suggest that magmas parental to the GMLC were derived from a depleted mantle source. However, Nd isotopic data for the GMLC plot distinctly below data for the depleted mantle source cited by DePaolo and thus suggest that the parental magmas of the GMLC were either contaminated by Proterozoic crust of the southern midcontinent or were derived from a heterogenous mantle source region that had variable initial Nd isotopic compositions.

  12. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; N. Nagabhushana; Thomas W. Eagar; Harold R. Larson; Raymundo Arroyave; X.-D Zhou; Y.-W. Shin; H.U. Anderson; Nigel Browning; Alan Jacobson; C.A. Mims

    2003-11-01T23:59:59.000Z

    The present quarterly report describes some of the initial studies on newer compositions and also includes newer approaches to address various materials issues such as in metal-ceramic sealing. The current quarter's research has also focused on developing a comprehensive reliability model for predicting the structural behavior of the membranes in realistic conditions. In parallel to industry provided compositions, models membranes have been evaluated in varying environment. Of importance is the behavior of flaws and generation of new flaws aiding in fracture. Fracture mechanics parameters such as crack tip stresses are generated to characterize the influence of environment. Room temperature slow crack growth studies have also been initiated in industry provided compositions. The electrical conductivity and defect chemistry of an A site deficient compound (La{sub 0.55}Sr{sub 0.35}FeO{sub 3}) was studied. A higher conductivity was observed for La{sub 0.55}Sr{sub 0.35}FeO{sub 3} than that of La{sub 0.60}Sr{sub 0.40}FeO{sub 3} and La{sub 0.80}Sr{sub 0.20}FeO{sub 3}. Defect chemistry analysis showed that it was primarily contributed by a higher carrier concentration in La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. Moreover, the ability for oxygen vacancy generation is much higher in La{sub 0.55}Sr{sub 0.35}FeO{sub 3} as well, which indicates a lower bonding strength between Fe-O and a possible higher catalytic activity for La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. The program continued to investigate the thermodynamic properties (stability and phase separation behavior) and total conductivity of prototype membrane materials. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previous report listed initial measurements on a sample of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-x} prepared in-house by Praxair. Subsequently, a second sample of powder from a larger batch of sample were characterized and compared with the results from the previous batch.

  13. FORMATION OF MOLECULAR OXYGEN AND OZONE ON AMORPHOUS SILICATES

    SciTech Connect (OSTI)

    Jing Dapeng; He Jiao; Vidali, Gianfranco [Physics Department, Syracuse University, Syracuse, NY 13244 (United States); Brucato, John Robert; Tozzetti, Lorenzo [Osservatorio Astrofisico di Arcetri, INAF, I-50125 Florence (Italy); De Sio, Antonio [Department of Physics and Astronomy, University of Florence, I-50125 Florence (Italy)

    2012-09-01T23:59:59.000Z

    Oxygen in the interstellar medium is seen in the gas phase, in ices (incorporated in H{sub 2}O, CO, and CO{sub 2}), and in grains such as (Mg{sub x} Fe{sub 1-x} )SiO{sub 3} or (Mg{sub x} Fe{sub 1-x} ){sub 2}SiO{sub 4}, 0 < x < 1. In this investigation, we study the diffusion of oxygen atoms and the formation of oxygen molecules and ozone on the surface of an amorphous silicate film. We find that ozone is formed at low temperature (<30 K), and molecular oxygen forms when the diffusion of oxygen atoms becomes significant, at around 60 K. This experiment, besides being the first determination of the diffusion energy barrier (1785 {+-} 35 K) for oxygen atoms on a silicate surface, suggests bare silicates as a possible storage place for oxygen atoms in low-A{sub v} environments.

  14. Transportation of medical isotopes

    SciTech Connect (OSTI)

    Nielsen, D.L.

    1997-11-19T23:59:59.000Z

    A Draft Technical Information Document (HNF-1855) is being prepared to evaluate proposed interim tritium and medical isotope production at the Fast Flux Test Facility (FFTF). This assessment examines the potential health and safety impacts of transportation operations associated with the production of medical isotopes. Incident-free and accidental impacts are assessed using bounding source terms for the shipment of nonradiological target materials to the Hanford Site, the shipment of irradiated targets from the FFTF to the 325 Building, and the shipment of medical isotope products from the 325 Building to medical distributors. The health and safety consequences to workers and the public from the incident-free transportation of targets and isotope products would be within acceptable levels. For transportation accidents, risks to works and the public also would be within acceptable levels. This assessment is based on best information available at this time. As the medical isotope program matures, this analysis will be revised, if necessary, to support development of a final revision to the Technical Information Document.

  15. Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy

    E-Print Network [OSTI]

    Myers, Tom

    Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy A. J. Ptak, L. J-assisted molecular-beam epitaxy to study the dependence of oxygen incorporation on polarity and oxygen partial pressure. Oxygen incorporates at a rate ten times faster on nitrogen-polar GaN than on the Ga polarity

  16. Neutron Stimulated Emission Computed Tomography of Stable Isotopes

    E-Print Network [OSTI]

    on the development of a new molecular imaging technique using inelastic scattering of fast neutrons. Earlier studies characteristic gamma photons through inelastic scattering of an external neutron beam. These stable isotopes canNeutron Stimulated Emission Computed Tomography of Stable Isotopes Carey E. Floyd Jr.*ab , Calvin

  17. In-operando hard X-ray photoelectron spectroscopy study on the impact of current compliance and switching cycles on oxygen and carbon defects in resistive switching Ti/HfO{sub 2}/TiN cells

    SciTech Connect (OSTI)

    Sowinska, Malgorzata, E-mail: sowinska@ihp-microelectronics.com; Bertaud, Thomas; Walczyk, Damian; Calka, Pauline; Walczyk, Christian [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Thiess, Sebastian [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Alff, Lambert [Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Schroeder, Thomas [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

    2014-05-28T23:59:59.000Z

    In this study, direct experimental materials science evidence of the important theoretical prediction for resistive random access memory (RRAM) technologies that a critical amount of oxygen vacancies is needed to establish stable resistive switching in metal-oxide-metal samples is presented. In detail, a novel in-operando hard X-ray photoelectron spectroscopy technique is applied to non-destructively investigates the influence of the current compliance and direct current voltage sweep cycles on the Ti/HfO{sub 2} interface chemistry and physics of resistive switching Ti/HfO{sub 2}/TiN cells. These studies indeed confirm that current compliance is a critical parameter to control the amount of oxygen vacancies in the conducting filaments in the oxide layer during the RRAM cell operation to achieve stable switching. Furthermore, clear carbon segregation towards the Ti/HfO{sub 2} interface under electrical stress is visible. Since carbon impurities impact the oxygen vacancy defect population under resistive switching, this dynamic carbon segregation to the Ti/HfO{sub 2} interface is suspected to negatively influence RRAM device endurance. Therefore, these results indicate that the RRAM materials engineering needs to include all impurities in the dielectric layer in order to achieve reliable device performance.

  18. Isotopically selective, Doppler-free, saturation spectroscopy of lutetium isotopes via resonance ionization mass spectrometry

    SciTech Connect (OSTI)

    Fearey, B.L.; Parent, D.C.; Keller, R.A.; Miller, C.M.

    1988-01-01T23:59:59.000Z

    A new technique utilizing RIMS to obtain very high resolution atomic spectra with isotopic selectivity has been demonstrated. This technique allows the precise determination of HF splitting constants, limited only by the transition's natural linewidth. In addition, it is also feasible with this technique to accurately determine atomic isotope shifts. The exact determination of HF component line positions provides data for isotopically selective ionization which, in turn, will increase RIMS' dynamic range. Future work includes the incorporation of a /open quotes/vibrating/close quotes/ mirror and the study of rarer isotopes, i.e., /sup 174/Lu, /sup 173/Lu, /sup 172/Lu, /sup 171/Lu, and possibly, /sup 170/Lu. 13 refs., 3 figs.

  19. Significance of Isotopically Labile Organic Hydrogen in Thermal Maturation of Organic Matter

    SciTech Connect (OSTI)

    Arndt Schimmelmann; Maria Mastalerz

    2010-03-30T23:59:59.000Z

    Isotopically labile organic hydrogen in fossil fuels occupies chemical positions that participate in isotopic exchange and in chemical reactions during thermal maturation from kerogen to bitumen, oil and gas. Carbon-bound organic hydrogen is isotopically far less exchangeable than hydrogen bound to nitrogen, oxygen, or sulfur. We explore why organic hydrogen isotope ratios express a relationship with organic nitrogen isotope ratios in kerogen at low to moderate maturity. We develop and apply new techniques to utilize organic D/H ratios in organic matter fractions and on a molecular level as tools for exploration for fossil fuels and for paleoenvironmental research. The scope of our samples includes naturally and artificially matured substrates, such as coal, shale, oil and gas.

  20. Direct Observation of the Oxygenated Species during Oxygen Reduction...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Observation of the Oxygenated Species during Oxygen Reduction on a Platinum Fuel Cell Cathode Friday, December 20, 2013 Fuel Cell Figure 1 Figure 1. In situ x-ray...

  1. A combined Sm-Nd, Rb-Sr, and U-Pb isotopic study of Mg-suite norite 78238: Further evidence for early differentiation of the Moon

    SciTech Connect (OSTI)

    Edmunson, J; E.Borg, L; Nyquist, L E; Asmerom, Y

    2008-11-17T23:59:59.000Z

    Lunar Mg-suite norite 78238 was dated using the Sm-Nd, Rb-Sr, and U-Pb isotopic systems in order to constrain the age of lunar magma ocean solidification and the beginning of Mg-suite magmatism, as well as to provide a direct comparison between the three isotopic systems. The Sm-Nd isotopic system yields a crystallization age for 78238 of 4334 {+-} 37 Ma and an initial {var_epsilon}{sub Nd}{sup 143} value of -0.27 {+-} 0.74. The age-initial {var_epsilon}{sub Nd}{sup 143} (T-I) systematics of a variety of KREEP-rich samples, including 78238 and other Mg-suite rocks, KREEP basalts, and olivine cumulate NWA 773, suggest that lunar differentiation was completed by 4492 {+-} 61 Ma assuming a Chondritic Uniform Reservoir bulk composition for the Moon. The Rb-Sr isotopic systematics of 78238 were disturbed by post-crystallization processes. Nevertheless, selected data points yield two Rb-Sr isochrons. One is concordant with the Sm-Nd crystallization age, 4366 {+-} 53 Ma. The other is 4003 {+-} 95 Ma and is concordant with an Ar-Ar age for 78236. The {sup 207}Pb-{sup 206}Pb age of 4333 {+-} 59 Ma is concordant with the Sm-Nd age. The U-Pb isotopic systematics of 78238 yield linear arrays equivalent to younger ages than the Pb-Pb system, and may reflect fractionation of U and Pb during sample handling. Despite the disturbed nature of the U-Pb systems, a time-averaged {mu} ({sup 238}U/{sup 204}Pb) value of the source can be estimated at 27 {+-} 30 from the Pb-Pb isotopic systematics. Because KREEP-rich samples are likely to be derived from source regions with the highest U/Pb ratios, the relatively low {mu} value calculated for the 78238 source suggests the bulk Moon does not have an exceedingly high {mu} value.

  2. doi:10.1016/j.gca.2003.12.008 Nd-, O-, and H-isotopic evidence for complex, closed-system fluid evolution of the

    E-Print Network [OSTI]

    Siebel, Wolfgang

    , Eberhard-Karls-Universita¨t, Wilhelmstra e 56, D-72074 Tu¨bingen, Germany 2 Institut de Mine´ralogie et Ge, clinopyroxene, and olivine separates ( 5.2 to 5.7 relative to VSMOW) and neodymium isotope compositions ( Nd. In contrast to the homogeneous oxygen and neodymium isotopic data, D values for hand-picked amphibole

  3. Underground coal gasification using oxygen and steam

    SciTech Connect (OSTI)

    Yang, L.H.; Zhang, X.; Liu, S. [China University of Mining & Technology, Xuzhou (China)

    2009-07-01T23:59:59.000Z

    In this paper, through model experiment of the underground coal gasification, the effects of pure oxygen gasification, oxygen-steam gasification, and moving-point gasification methods on the underground gasification process and gas quality were studied. Experiments showed that H{sub 2} and CO volume fraction in product gas during the pure oxygen gasification was 23.63-30.24% and 35.22-46.32%, respectively, with the gas heating value exceeding 11.00 MJ/m{sup 3}; under the oxygen-steam gasification, when the steam/oxygen ratio stood at 2: 1, gas compositions remained virtually stable and CO + H{sub 2} was basically between 61.66 and 71.29%. Moving-point gasification could effectively improve the changes in the cavity in the coal seams or the effects of roof inbreak on gas quality; the ratio of gas flowing quantity to oxygen supplying quantity was between 3.1:1 and 3.5:1 and took on the linear changes; on the basis of the test data, the reasons for gas quality changes under different gasification conditions were analyzed.

  4. Spatial periphery of lithium isotopes

    SciTech Connect (OSTI)

    Galanina, L. I., E-mail: galan_lidiya@mail.ru; Zelenskaja, N. S. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2013-12-15T23:59:59.000Z

    The spatial structure of lithium isotopes is studied with the aid of the charge-exchange and (t, p) reactions on lithium nuclei. It is shown that an excited isobaric-analog state of {sup 6}Li (0{sup +}, 3.56MeV) has a halo structure formed by a proton and a neutron, that, in the {sup 9}Li nucleus, there is virtually no neutron halo, and that {sup 11}Li is a Borromean nucleus formed by a {sup 9}Li core and a two-neutron halo manifesting itself in cigar-like and dineutron configurations.

  5. A direct and rapid leaf water extraction method for isotopic analysis

    E-Print Network [OSTI]

    Yakir, Dan

    Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot, Israel for isotopic analysis via pyrolysis gas chromatography isotope ratio mass spectrometry (PYR/GC/IRMS). The new-scale studies that require high-throughput leaf water isotopic analysis. Copyright # 2008 John Wiley & Sons, Ltd

  6. COUPLING LEAD ISOTOPE ANALYSIS AND PETROGRAPHY TO CHARACTERIZE FABRICS OF STORAGE AND TRADE

    E-Print Network [OSTI]

    Claeys, Philippe

    COUPLING LEAD ISOTOPE ANALYSIS AND PETROGRAPHY TO CHARACTERIZE FABRICS OF STORAGE AND TRADE Brussels, Belgium 6 Director of research at Hala Sultan Tekke, Area 8, Cyprus Lead isotopes, thin sections and com- pared to lead isotope results on the same samples. This study shows that a specific

  7. LEAD ISOTOPIC ANALYSIS FOR THE IDENTIFICATION OF LATE BRONZE AGE POTTERY FROM HALA SULTAN

    E-Print Network [OSTI]

    Claeys, Philippe

    LEAD ISOTOPIC ANALYSIS FOR THE IDENTIFICATION OF LATE BRONZE AGE POTTERY FROM HALA SULTAN TEKKE, 9000 Ghent 5 Department of Geology, Université de Liège, Allée du 6­Août B18, 4000 Liège Lead isotopic the effectiveness of using lead isotopic analysis in provenance studies, along with other analytical techniques

  8. Hydration of DNA by tritiated water and isotope distribution: a study by /sup 1/H, /sup 2/H, and /sup 3/H NMR spectroscopy

    SciTech Connect (OSTI)

    Mathur-De Vre, R.; Grimee-Declerck, R.; Lejeune, P.; Bertinchamps, A.J.

    1982-06-01T23:59:59.000Z

    The hydration layer of DNA (0.75%) in tritiated water represents 3.5% of solvent /sup 3/HHO. The combined effects of temperature (-6 to -40/sup 0/C) and H/sub 2/O//sup 2/H/sub 2/O solvent composition on the spin-lattice relaxation times of water protons and deuterons suggest selective distribution of isotopes in the hydration layer. The ''hydration isotope'' effect and the localization of tritiated water molecules in the hydration layer of DNA have important implications in describing the radiobiological effects of tritiated water because the initial molecular damage caused by /sup 3/HHO (internal radiation source) localizes close to /sup 3/H due to the short range and low energy of /sup 3/H ..beta.. rays.

  9. Serum carbon and nitrogen stable isotopes as potential biomarkers of dietary intake and their relation with incident type 2 diabetes: the EPIC-Norfolk study

    E-Print Network [OSTI]

    Patel, Pinal S.; Cooper, Andrew J.M.; O’Connell, Tamsin C.; Kuhnle, Gunter G.C.; Kneale, Catherine K.; Mulligan, Angela M.; Luben, Robert N.; Brage, Soren; Khaw, Kay-Tee; Wareham, Nicholas J.; Forouhi, Nita G.

    2014-07-02T23:59:59.000Z

    as potential nutritional biomarkers for dis- tinguishing between meat, fish, and plant-based foods, which are isotopically distinct. The technique has a long history in ar- cheology and ecology as a method of dietary analysis (14, 15), but few epidemiologic... intake (g/d) was calculated from the frequency and amount (medium serving size) of each reported food by using in- house software (30). Protein intake from different food sources (fish, meat, dairy products, egg, vegetables, and cereal) was calculated...

  10. 7, 1271512750, 2007 Hydrogen isotope

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    imply that there must be a very strong concomitant isotopic enrichment in the radical channel (CH2O + hACPD 7, 12715­12750, 2007 Hydrogen isotope fractionation in the photolysis of formaldehyde T. S a Creative Commons License. Atmospheric Chemistry and Physics Discussions Hydrogen isotope fractionation

  11. Oxygen Concentration Microgradients for Cell Culture

    E-Print Network [OSTI]

    Park, Jaehyun

    2010-01-01T23:59:59.000Z

    The Chemotactic Effect of Oxygen on Bacteria,” J. Pathol.Measurement and Control of Oxygen Levels in MicrofluidicA Microfabricated Electrochemical Oxygen Generator for High-

  12. Oxygen abundances in the most oxygen-rich spiral galaxies

    E-Print Network [OSTI]

    L. S. Pilyugin; T. X. Thuan; J. M. Vilchez

    2006-01-06T23:59:59.000Z

    Oxygen abundances in the spiral galaxies expected to be richest in oxygen are estimated. The new abundance determinations are based on the recently discovered ff-relation between auroral and nebular oxygen line fluxes in HII regions. We find that the maximum gas-phase oxygen abundance in the central regions of spiral galaxies is 12+log(O/H)~8.75. This value is significantly lower than the previously accepted value. The central oxygen abundance in the Milky Way is similar to that in other large spirals.

  13. High pressure oxygen furnace

    DOE Patents [OSTI]

    Morris, Donald E. (Kensington, CA)

    1992-01-01T23:59:59.000Z

    A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior.

  14. High pressure oxygen furnace

    DOE Patents [OSTI]

    Morris, D.E.

    1992-07-14T23:59:59.000Z

    A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized, the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior. 5 figs.

  15. Using in situ X-ray absorption spectroscopy to study the local structure and oxygen ion conduction mechanism in (La{sub 0.6}Sr{sub 0.4})(Co{sub 0.2}Fe{sub 0.8})O{sub 3-{delta}}

    SciTech Connect (OSTI)

    Itoh, Takanori, E-mail: tknitoh@seimichemical.co.jp [AGC SeimiChemical Co., Ltd., 3-2-10 Chigasaki, Chigasaki City, Kanagawa 253-8585 (Japan); Nakayama, Masanobu [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya-city, Aichi 466-8555 (Japan)

    2012-08-15T23:59:59.000Z

    To study the local structure and oxygen ion conduction mechanism in (La{sub 0.6}Sr{sub 0.4})(Co{sub 0.2}Fe{sub 0.8})O{sub 3-{delta}} (LSCF) as a function of the oxygen partial pressure (P(O{sub 2})), in situ the Co and Fe K-edge X-ray absorption spectroscopy (XAS) was measured at elevated temperatures of 900 and 1000 K. The reduction of the Co and Fe valence, i.e., the oxygen content (3-{delta}) in LSCF, followed the change of P(O{sub 2}) from 1 to 10{sup -4} atm during{approx}4000 s. The quantitative analysis of the X-ray absorption near edge structure (XANES) and the extended X-ray absorption fine structure (EXAFS) indicated that the Fe valence was higher than the Co valence at oxidative condition ({delta} Almost-Equal-To 0) in LSCF. Whereas the Co valence decreased more than the Fe valence after reduction of P(O{sub 2}) at both 900 and 1000 K. From the relaxation plots of the valence and the oxygen content (3-{delta}) for Co and Fe after changing P(O{sub 2}), we successfully determined D{sub chem} and E{sub a} of an oxygen ion migration around Co and Fe in LSCF. A structural model with and without oxygen vacancies and an oxygen ion conduction mechanism for LSCF are proposed based on these results. - Graphical abstract: A structural model with and without oxygen vacancies, and the oxygen ion conduction mechanism of LSCF were speculated. In other words, oxygen vacancies would form more preferentially around Co than Fe from the results of in situ XAS analysis during reduction, and oxygen ions needs to pass through at the vicinity of Fe from the results of D{sub chem} and E{sub a}. Highlights: Black-Right-Pointing-Pointer Study of the oxygen ion conduction mechanism in (La{sub 0.6}Sr{sub 0.4})(Co{sub 0.2}Fe{sub 0.8})O{sub 3-{delta}} (LSCF). Black-Right-Pointing-Pointer Using in situ X-ray absorption for study of valence and oxygen diffusion coefficient. Black-Right-Pointing-Pointer The oxygen vacancies should be preferentially localized around Co in LSCF. Black-Right-Pointing-Pointer The values of the dynamics parameters for Co and Fe are close to each other.

  16. On the solar nickel and oxygen abundances

    E-Print Network [OSTI]

    Pat Scott; Martin Asplund; Nicolas Grevesse; A. Jacques Sauval

    2009-01-27T23:59:59.000Z

    Determinations of the solar oxygen content relying on the neutral forbidden transition at 630 nm depend upon the nickel abundance, due to a Ni I blend. Here we rederive the solar nickel abundance, using the same ab initio 3D hydrodynamic model of the solar photosphere employed in the recent revision of the abundances of C, N, O and other elements. Using 17 weak, unblended lines of Ni I together with the most accurate atomic and observational data available we find log epsilon_Ni = 6.17 +/- 0.02 (statistical) +/- 0.05 (systematic), a downwards shift of 0.06 to 0.08 dex relative to previous 1D-based abundances. We investigate the implications of the new nickel abundance for studies of the solar oxygen abundance based on the [O I] 630 nm line in the quiet Sun. Furthermore, we demonstrate that the oxygen abundance implied by the recent sunspot spectropolarimetric study of Centeno & Socas-Navarro needs to be revised downwards from log epsilon_O = 8.86 +/- 0.07 to 8.71 +/- 0.10. This revision is based on the new nickel abundance, application of the best available gf-value for the 630 nm forbidden oxygen line, and a more transparent treatment of CO formation. Determinations of the solar oxygen content relying on forbidden lines now appear to converge around log epsilon_O = 8.7.

  17. This journal is c the Owner Societies 2011 Phys. Chem. Chem. Phys., 2011, 13, 421427 421 On the electron-induced isotope fractionation in low temperature

    E-Print Network [OSTI]

    Kaiser, Ralf I.

    . Sivaraman,a A. M. Mebel,b N. J. Mason,*a D. Babikovc and R. I. Kaiser*de Received 4th May 2010, Accepted 26 and isotopologues involving non-thermal, non-equilibrium chemistry by irradiation of oxygen ices with high energy measured oxygen isotopes in the solar wind and from comet Wild 2 by collecting (and returning) `dust

  18. Carbon kinetic isotope effects on the hydration of carbon dioxide and the dehydration of bicarbonate ion

    SciTech Connect (OSTI)

    Marlier, J.F.; O'Leary, M.H.

    1984-09-05T23:59:59.000Z

    /sup 13/C kinetic isotope effects on the hydration of CO/sub 2/ and the dehydration of HCO/sub 3//sup -/ in aqueous solution have been measured by rapid removal of the product and conversion to an isotopically stable form, followed by isotope-ratio analysis. The isotope effect on hydration is k/sup 12//k/sup 13/ = 1.0069 +/- 0.0003 at 24/sup 0/C. The isotope effect on dehydration is 1.0147 +/- 0.0007. The ratio of these two values gives an equilibrium isotope effect of K/sup 12//K/sup 13/ = 1.0077, in good agreement with previously measured values. The small magnitudes of the kinetic isotope effects indicate that the transition state for conversion of HCO/sub 3//sup -/ to CO/sub 2/ is very similar to that of HCO/sub 3//sup -/. This information together with previously measured solvent isotope effects indicates that the mechanism of HCO/sub 3//sup -/ dehydration probably involves general-acid-catalyzed donation of a proton from H/sub 3/O/sup +/ to the departing oxygen, rather than unimolecular decomposition of the zwitterion H/sub 2/O/sup +/-CO/sub 2//sup -/ in the rate-determining step. 21 references, 2 figures.

  19. Contiguous Platinum Monolayer Oxygen Reduction Electrocatalysts...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Contiguous Platinum Monolayer Oxygen Reduction Electrocatalysts on High-Stability-Low-Cost Supports Contiguous Platinum Monolayer Oxygen Reduction Electrocatalysts on...

  20. Stabilization of Platinum Nanoparticle Electrocatalysts for Oxygen...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Platinum Nanoparticle Electrocatalysts for Oxygen Reduction Using Poly(diallyldimethylammonium chloride). Stabilization of Platinum Nanoparticle Electrocatalysts for Oxygen...

  1. Preliminary results obtained with an apparatus for studying the effect of carbon dioxide on consumption of oxygen by respiring cotton roots

    E-Print Network [OSTI]

    Hinesly, Thomas Daniel

    1956-01-01T23:59:59.000Z

    'ai . ivy. -ioX~&ie6-'Xe;:: -', -. " -':. . ;;, ?, :;=-'--, -', :?. q =. ==-. -~Wm yekkvy~apbM kii4hok-'M4xeleiW-'~ ~:mC ? -' EXCOiCBCCk . $28 ) y, Sg. :C98BQ 5g 4 p3. @5$gRM hli4Z'838 C4X i&5 @tibet 4@BX, ~ B, QgDQ@p. ~ gyle~'ggq@ ~~ ~ ~~w ~ZQSi@B tkg..., giveri poet d4metyx 8't'j-eyeeMfe. te~~ ' . --, 'i~~'-", ~:4emn4a- ef::thj:Xe4ewmgt -eo ji of-;the ~4="'=, -=-" =- -:: ' t -~e' be9ijj eet'Retied~; bent M' oxygen. tempted heeezey cf. -'. oxL4k't'lQxl Qf', eR~sg llpectl'g 4epszl@exlt 'Qp55, ~e4...

  2. Oxygen Transport Ceramic Membranes

    SciTech Connect (OSTI)

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-05-01T23:59:59.000Z

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped Ti-substituted perovskites, La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Ti{sub x}O{sub 3}, with 0 {le} x {le} 0.20, were investigated by neutron diffraction, magnetization, electric resistivity, and magnetoresistance (MR) measurements. All samples show a rhombohedral structure (space group R3C) from 10 K to room temperature. At room temperature, the cell parameters a, c and the unit cell volume increase with increasing Ti content. However, at 10 K, the cell parameter a has a maximum value for x = 0.10, and decreases for x > 0.10, while the unit cell volume remains nearly constant for x > 0.10. The average (Mn,Ti)-O bond length increases up to x = 0.15, and the (Mn,Ti)-O-(Mn,Ti) bond angle decreases with increasing Ti content to its minimum value at x = 0.15 at room temperature. Below the Curie temperature TC, the resistance exhibits metallic behavior for the x {le} 0.05 samples. A metal (semiconductor) to insulator transition is observed for the x {ge} 0.10 samples. A peak in resistivity appears below TC for all samples, and shifts to a lower temperature as x increases. The substitution of Mn by Ti decreases the 2p-3d hybridization between O and Mn ions, reduces the bandwidth W, and increases the electron-phonon coupling. Therefore, the TC shifts to a lower temperature and the resistivity increases with increasing Ti content. A field-induced shift of the resistivity maximum occurs at x {le} 0.10 compounds. The maximum MR effect is about 70% for La{sub 0.7}Sr{sub 0.3}Mn{sub 0.8}Ti{sub 0.2}O{sub 3}. The separation of TC and the resistivity maximum temperature T{sub {rho},max} enhances the MR effect in these compounds due to the weak coupling between the magnetic ordering and the resistivity as compared with La{sub 0.7}Sr{sub 0.3}MnO{sub 3}. The bulk densities of the membranes were determined using the Archimedes method. The bulk density was 5.029 and 5.57 g/cc for LSFT and dual phase membranes, respectively. The microstructure of the dual phase membrane was analyzed using SEM. It is evident from the micrograph that the microstructure is composed of dual phases. The dense circular regions are enclosed by the less dense, continuous phase which accommodates most of the pores. The pores are normally aggregated and found clustered along the dense regions where as the dense regions do not have pores. Upon closer observation of the micrograph it is revealed that the dense region has a clear circular cleavage or crack as their boundary. The circular cleavage clearly encompasses a dense region and which consists of no pore or any flaw that is visible. The size distribution of the dense, discontinuous regions is varying from 5 to 20 {micro}m with a D{sub 50} of 15 {micro}m. The grain size distribution was estimated from the micrographs using image analysis and a unimodal distribution of grains was observed with an average grain size of 1.99 {micro}m. The chemical compositions of the membranes were analyzed using EDS analysis and no other impurities were observed. The XRD analysis was carried out for the membranes and the phase purity was confirmed. The fracture toughness of LSFT membranes at room temperature has to be calculated using the Vickers indentation method. An electrochemical cell has been designed and built for measurements of the ionic conductivity by the use of blocking electrodes. Preliminary measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Modifications to the apparatus to improve the data quality have been completed. Electron microscopy studies of the origin of the slow kinetics on reduction of ferrites have been initiated. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradient

  3. Laser isotope separation of erbium and other isotopes

    DOE Patents [OSTI]

    Haynam, Christopher A. (3035 Ferdale Ct., Pleasanton, CA 94566); Worden, Earl F. (117 Vereda del Ciervo, Diablo, CA 94528)

    1995-01-01T23:59:59.000Z

    Laser isotope separation is accomplished using at least two photoionization pathways of an isotope simultaneously, where each pathway comprises two or more transition steps. This separation method has been applied to the selective photoionization of erbium isotopes, particularly for the enrichment of .sup.167 Er. The hyperfine structure of .sup.167 Er was used to find two three-step photoionization pathways having a common upper energy level.

  4. Laser isotope separation of erbium and other isotopes

    DOE Patents [OSTI]

    Haynam, C.A.; Worden, E.F.

    1995-08-22T23:59:59.000Z

    Laser isotope separation is accomplished using at least two photoionization pathways of an isotope simultaneously, where each pathway comprises two or more transition steps. This separation method has been applied to the selective photoionization of erbium isotopes, particularly for the enrichment of {sup 167}Er. The hyperfine structure of {sup 167}Er was used to find two three-step photoionization pathways having a common upper energy level. 3 figs.

  5. Composite oxygen transport membrane

    DOE Patents [OSTI]

    Christie, Gervase Maxwell; Lane, Jonathan A.

    2014-08-05T23:59:59.000Z

    A method of producing a composite oxygen ion membrane and a composite oxygen ion membrane in which a porous fuel oxidation layer and a dense separation layer and optionally, a porous surface exchange layer are formed on a porous support from mixtures of (Ln.sub.1-xA.sub.x).sub.wCr.sub.1-yB.sub.yO.sub.3-.delta. and a doped zirconia. In the porous fuel oxidation layer and the optional porous surface exchange layer, A is Calcium and in the dense separation layer A is not Calcium and, preferably is Strontium. Preferred materials are (La.sub.0.8Ca.sub.0.2).sub.0.95Cr.sub.0.5Mn.sub.0.5O.sub.3-.delta. for the porous fuel oxidation and optional porous surface exchange layers and (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.5Fe.sub.0.5O.sub.3-.delta. for the dense separation layer. The use of such materials allows the membrane to sintered in air and without the use of pore formers to reduce membrane manufacturing costs. The use of materials, as described herein, for forming the porous layers have application for forming any type of porous structure, such as a catalyst support.

  6. Carbon isotope variability across the Ediacaran Yangtze platform in South China: Implications for a large surface-to-deep

    E-Print Network [OSTI]

    Jiang, Ganqing

    Carbon isotope variability across the Ediacaran Yangtze platform in South China: Implications Formation; Dengying Formation; Yangtze platform; South China 1. Introduction Recent carbon isotope studies of South China and position of the Ediacaran carbonate platform margin (coarse dashed line). (B

  7. Surface-cycling of rhenium and its isotopes

    E-Print Network [OSTI]

    Miller, Christian Alexander

    2009-01-01T23:59:59.000Z

    The application of elemental and isotopic metal palaeoredox tracers to the geologic past rests on an understanding of modern metal cycles. This study reevaluates the surface-cycling of Mo and Re in near-surface reservoirs. ...

  8. High Selectivity Oxygen Delignification

    SciTech Connect (OSTI)

    Arthur J. Ragauskas

    2005-09-30T23:59:59.000Z

    The overall objective of this program was to develop improved extended oxygen delignification (EOD) technologies for current U.S. pulp mill operations. This was accomplished by: (1) Identifying pulping conditions that optimize O and OO performance; (2) Identifying structural features of lignin that enhance reactivity towards EOD of high kappa pulps; (3) Identifying factors minimizing carbohydrate degradation and improve pulp strength of EOD high kappa pulps; (4) Developing a simple, reproducible method of quantifying yield gains from EOD; and (5) Developing process conditions that significantly reduce the capital requirements of EOD while optimizing the yield benefits. Key research outcomes included, demonstrating the use of a mini-O sequence such as (E+O)Dkf:0.05(E+O) or Dkf:0.05(E+O)(E+O) without interstage washing could capture approximately 60% of the delignification efficiency of a conventional O-stage without the major capital requirements associated with an O-stage for conventional SW kraft pulps. The rate of formation and loss of fiber charge during an O-stage stage can be employed to maximize net fiber charge. Optimal fiber charge development and delignification are two independent parameters and do not parallel each other. It is possible to utilize an O-stage to enhance overall cellulosic fiber charge of low and high kappa SW kraft pulps which is beneficial for physical strength properties. The application of NIR and multi-variant analysis was developed into a rapid and simple method of determining the yield of pulp from an oxygen delignification stage that has real-world mill applications. A focus point of this program was the demonstration that Kraft pulping conditions and oxygen delignification of high and low-kappa SW and HW pulps are intimately related. Improved physical pulp properties and yield can be delivered by controlling the H-factor and active alkali charge. Low AA softwood kraft pulp with a kappa number 30 has an average improvement of 2% in yield and 4 cP in viscosity in comparison to high AA pulp for the oxygen delignification. This difference is also seen for high-kappa SW kraft pulps with an average improvement of {approx}3% in yield and 3 cP in viscosity for low AA high kappa number 50 pulp. Low AA hardwood kappa number 20 pulp had an average improvement of {approx}4% in yield and 6-12 cP in viscosity as compared to high AA pulp. Lower kraft cooking temperature (160 vs. 170 C) in combination with the medium AA provides a practical approach for integrating high kappa pulping of hardwoods (i.e., low rejects) with an advanced extended oxygen delignification stage. ECF pulp bleaching of low and high kappa kraft SW and HW pulps exhibit comparable optical and physical strength properties when bleached D(EPO)D.

  9. Water isotopes and the general circulation

    E-Print Network [OSTI]

    Noone, David

    is depleted. #12;Distillation: vapor and condensate Isotopic fractionation -35 -30 -25 -20 -15 -10 -5 0 5 0 0 of idealized isotopic fractionation Expression of isotopic fractionation in nature Attributing signals" 18 = (R/Rstandard-1)x1000 R = moles of H2 18O/moles of H2 16O #12;Isotopic fractionation Isotopic

  10. Oxygen-reducing catalyst layer

    DOE Patents [OSTI]

    O'Brien, Dennis P. (Maplewood, MN); Schmoeckel, Alison K. (Stillwater, MN); Vernstrom, George D. (Cottage Grove, MN); Atanasoski, Radoslav (Edina, MN); Wood, Thomas E. (Stillwater, MN); Yang, Ruizhi (Halifax, CA); Easton, E. Bradley (Halifax, CA); Dahn, Jeffrey R. (Hubley, CA); O'Neill, David G. (Lake Elmo, MN)

    2011-03-22T23:59:59.000Z

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  11. Studies of the C-terminal Region of the Gamma Subunit of the Chloroplast ATP Synthase

    E-Print Network [OSTI]

    He, Feng

    2008-06-18T23:59:59.000Z

    and Girvin 1999). 4. The Binding Change Mechanism and Rotational Catalysis of the ATP Synthase Isotopic exchange studies of 18 O and 32 P revealed that the ? phosphate bond of the nucleotide is broken and reformed with oxygen from water during... et al. 2003). The ? rotation has also been observed in EcF 1 (Omote, Sambonmatsu et al. 1999) and hybrid F 1 that contained ? and ? subunits from the bacterium Rhodospirillum rubrum and ? subunit from spinach chloroplast F 1 (Tucker, Schwarz et...

  12. Active Oxygen Vacancy Site for Methanol Synthesis from CO2 Hydrogenati...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Oxygen Vacancy Site for Methanol Synthesis from CO2 Hydrogenation on In2O3(110): A DFT Study. Active Oxygen Vacancy Site for Methanol Synthesis from CO2 Hydrogenation on...

  13. Acetone-Assisted Oxygen Vacancy Diffusion on TiO2(110). | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Acetone-Assisted Oxygen Vacancy Diffusion on TiO2(110). Acetone-Assisted Oxygen Vacancy Diffusion on TiO2(110). Abstract: We have studied the dynamic relationship between acetone...

  14. Isotopic mass-dependence of noble gas diffusion coefficients inwater

    SciTech Connect (OSTI)

    Bourg, I.C.; Sposito, G.

    2007-06-25T23:59:59.000Z

    Noble gas isotopes are used extensively as tracers inhydrologic and paleoclimatic studies. These applications requireknowledge of the isotopic mass (m) dependence of noble gas diffusioncoefficients in water (D), which has not been measured but is estimatedusing experimental D-values for the major isotopes along with an untestedrelationship from kinetic theory, D prop m-0.5. We applied moleculardynamics methods to determine the mass dependence of D for four noblegases at 298 K, finding that D prop m-beta with beta<0.2, whichrefutes the kinetic theory model underlying all currentapplications.

  15. Novel Isotope Effects and Organic Reaction Mechanisms

    E-Print Network [OSTI]

    Kelly, Kelmara K.

    2010-07-14T23:59:59.000Z

    to account for the observed isotope effects. In the dimerization of cyclopentadiene, novel "dynamic" isotope effects are observed on the 13C distribution in the product, and a method for the prediction of these isotope effects is developed here...

  16. am-be isotopic neutron: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of fast neutrons. Earlier studies characteristic gamma photons through inelastic scattering of an external neutron beam. These stable isotopes canNeutron Stimulated...

  17. Chromatographic hydrogen isotope separation

    DOE Patents [OSTI]

    Aldridge, Frederick T. (Livermore, CA)

    1981-01-01T23:59:59.000Z

    Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  18. ARM - Measurement - Isotope ratio

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDC documentationBarrow,ice particleSizegovMeasurementsIsotope ratio

  19. The marine biogeochemistry of zinc isotopes

    E-Print Network [OSTI]

    John, Seth G

    2007-01-01T23:59:59.000Z

    Zinc (Zn) stable isotopes can record information about important oceanographic processes. This thesis presents data on Zn isotopes in anthropogenic materials, hydrothermal fluids and minerals, cultured marine phytoplankton, ...

  20. Stable Isotope Fractionations in Biogeochemical Reactive Transport

    E-Print Network [OSTI]

    Druhan, Jennifer Lea

    2012-01-01T23:59:59.000Z

    characteristic of stable isotope enrichment. The values of !isotope ratios of sulfur in these sulfate samples demonstrated a clear enrichmentisotope ( 34 S) (Canfield, 2001). The characteristic enrichment

  1. Strategic Isotope Production | ornl.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Strategic Isotope Production SHARE Strategic Isotope Production Typical capsules used in the transport of 252Cf source material inside heavily shielded shipping casks. ORNL's...

  2. Isotopic Trends in Production of Superheavies

    SciTech Connect (OSTI)

    Antonenko, N.V. [Institut fuer Theoretische Physik der Justus-Liebig-Universitaet, D-35392 Giessen (Germany); Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Adamian, G.G.; Zubov, A.S. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Scheid, W. [Institut fuer Theoretische Physik der Justus-Liebig-Universitaet, D-35392 Giessen (Germany)

    2005-11-21T23:59:59.000Z

    The isotopic trends are discussed for cold and hot fusion reactions leading to superheavies. The possibilities of production of new isotopes in incomplete fusion reactions are treated.

  3. Oxygen detection using evanescent fields

    DOE Patents [OSTI]

    Duan, Yixiang (Los Alamos, NM); Cao, Weenqing (Los Alamos, NM)

    2007-08-28T23:59:59.000Z

    An apparatus and method for the detection of oxygen using optical fiber based evanescent light absorption. Methylene blue was immobilized using a sol-gel process on a portion of the exterior surface of an optical fiber for which the cladding has been removed, thereby forming an optical oxygen sensor. When light is directed through the optical fiber, transmitted light intensity varies as a result of changes in the absorption of evanescent light by the methylene blue in response to the oxygen concentration to which the sensor is exposed. The sensor was found to have a linear response to oxygen concentration on a semi-logarithmic scale within the oxygen concentration range between 0.6% and 20.9%, a response time and a recovery time of about 3 s, ant to exhibit good reversibility and repeatability. An increase in temperature from 21.degree. C. to 35.degree. C. does not affect the net absorption of the sensor.

  4. Isotope Research 229 Th production

    E-Print Network [OSTI]

    Isotope Research ­ 229 Th production We recently completed an ARRA-funded project of this type on 229 Th production reactions [Str11]. This long-lived isotope is important as a precursor to 225 Ac of accelerator production of 229 Th via the 230 Th(p,2n)229 Pa reaction. The 229 Pa decays primarily by electron

  5. Method of separating boron isotopes

    DOE Patents [OSTI]

    Jensen, Reed J. (Los Alamos, NM); Thorne, James M. (Provo, UT); Cluff, Coran L. (Provo, UT); Hayes, John K. (Salt Lake City, UT)

    1984-01-01T23:59:59.000Z

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)dichloroborane as the feed material. The photolysis can readily be achieved with CO.sub.2 laser radiation and using fluences significantly below those required to dissociate BCl.sub.3.

  6. Method of separating boron isotopes

    DOE Patents [OSTI]

    Jensen, R.J.; Thorne, J.M.; Cluff, C.L.

    1981-01-23T23:59:59.000Z

    A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)-dichloroborane as the feed material. The photolysis can readily by achieved with CO/sub 2/ laser radiation and using fluences significantly below those required to dissociate BCl/sub 3/.

  7. Low Oxygen Environments in Chesapeake Bay

    E-Print Network [OSTI]

    Boynton, Walter R.

    Low Oxygen Environments in Chesapeake Bay Jeremy Testa Chesapeake Biological Laboratory University of Maryland Center for Environmental Science Why we care about low oxygen? What causes low oxygen? Where and When does Chesapeake Bay lose oxygen? #12;#12;Hypoxia and Chesapeake Animals Low dissolved oxygen

  8. Stable isotopes in late Pennsylvanian brachiopods: stratigraphic and paleoenvironmental implications

    E-Print Network [OSTI]

    Zhang, Chuanlun

    1989-01-01T23:59:59.000Z

    STABLE ISOTOPES IN LATE PENNSYLVANIAN BRACHIOPODS: STRATIGRAPHIC AND PALEOENVIRONMENTAL IMPLICATIONS A Thesis by CHUANLUN ZHANG Submitted to the Office of Graduate Studies of Texas A%M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1989 Major Subject: Geology Stable Isotopes in Late Pennsylvanian Brachiopods: Stratigraphic and Paleoenvironmental Implications A Thesis by CHUANLUN ZHANG Approved as to the style and content by: Ethan L...

  9. Isotope separation by laser means

    DOE Patents [OSTI]

    Robinson, C. Paul (Los Alamos, NM); Jensen, Reed J. (Los Alamos, NM); Cotter, Theodore P. (Los Alamos, NM); Greiner, Norman R. (Los Alamos, NM); Boyer, Keith (Los Alamos, NM)

    1982-06-15T23:59:59.000Z

    A process for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium.

  10. OXYGEN DIFFUSION IN UO2-x

    E-Print Network [OSTI]

    Kim, K.C.

    2013-01-01T23:59:59.000Z

    ~ K.C. K:i.m, "Oxygen Diffusion in Hypostoichiometricsystem for enriching uo 2 in oxygen-18 or for stoichiometry+nal of Nuclear Materials OXYGEN DIFFUSION IN U0 2 _:x K.C.

  11. Oxygen transfer in the implant environment

    E-Print Network [OSTI]

    Goor, Jared Braden

    2007-01-01T23:59:59.000Z

    Temperature dependence of oxygen diffusion and consumptionRN. Influence of temperature on oxygen diffusion in hamster341-347, 1988. Cox ME. Oxygen Diffusion in Poly(dimethyl

  12. Oxygen impurity and microalloying effect in a Zr-based bulk metallic glass alloy

    E-Print Network [OSTI]

    Pennycook, Steve

    Oxygen impurity and microalloying effect in a Zr-based bulk metallic glass alloy C.T. Liu*, M composition Zr­10 at.%Al­5% Ti­17.9% Cu­14.6% Ni (BAM-11) was used to study the effects of oxygen impurities and microalloying on the microstructure and mechanical properties. Oxygen impurity at a level of 3000 appm

  13. PRIMARY RESEARCH PAPER Water column oxygen demand and sediment oxygen flux

    E-Print Network [OSTI]

    Mallin, Michael

    PRIMARY RESEARCH PAPER Water column oxygen demand and sediment oxygen flux: patterns of oxygen dissolved oxygen (DO) levels often occur during summer in tidal creeks along the southeastern coast of the USA. We analyzed rates of oxygen loss as water-column biochemical oxygen demand (BOD5) and sediment

  14. RESOLUTION OF URANIUM ISOTOPES WITH KINETIC PHOSPHORESCENCE ANALYSIS

    SciTech Connect (OSTI)

    Miley, Sarah M.; Hylden, Anne T.; Friese, Judah I.

    2013-04-01T23:59:59.000Z

    This study was conducted to test the ability of the Chemchek™ Kinetic Phosphorescence Analyzer Model KPA-11 with an auto-sampler to resolve the difference in phosphorescent decay rates of several different uranium isotopes, and therefore identify the uranium isotope ratios present in a sample. Kinetic phosphorescence analysis (KPA) is a technique that provides rapid, accurate, and precise determination of uranium concentration in aqueous solutions. Utilizing a pulsed-laser source to excite an aqueous solution of uranium, this technique measures the phosphorescent emission intensity over time to determine the phosphorescence decay profile. The phosphorescence intensity at the onset of decay is proportional to the uranium concentration in the sample. Calibration with uranium standards results in the accurate determination of actual concentration of the sample. Different isotopes of uranium, however, have unique properties which should result in different phosphorescence decay rates seen via KPA. Results show that a KPA is capable of resolving uranium isotopes.

  15. Investigation of the electrocatalytic oxygen reduction and evolution reactions in lithium–oxygen batteries

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zheng, Dong; Zhang, Xuran; Qu, Deyu; Yang, Xiao-Qing; Lee, Hung-Sui; Qu, Deyang

    2015-08-01T23:59:59.000Z

    Oxygen reduction and oxygen evolution reactions were studied on graphite electrodes with different crystal orientations. The kinetics for the redox couple O2/O2•- are very fast, therefore no catalyst seems necessary to assist the charge transfer process. Apparently, the main source of the overpotential for the O2 reduction reaction is from mass diffusion. Li2O2 becomes soluble in non-aqueous electrolytes in the presence of the tetraethylammonium tetrafluoroborate additive. The soluble B-O22- ions can be oxidized electro-catalytically. The edge orientation of graphite demonstrates superior catalytic activity for the oxidation over basal orientation. The findings reveal an opportunity for recharging Li-air batteries efficiently andmore »a new strategy of developing the catalyst for oxygen evolution reaction.« less

  16. Investigation of the electrocatalytic oxygen reduction and evolution reactions in lithium–oxygen batteries

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zheng, Dong [Univ. of Wisconsin, Milwaukee, WI (United States). Collece of Engineering and Applied Science; Zhang, Xuran [Wuhan Univ. of Technology, Wuhan (China). School of Science; Qu, Deyu [Wuhan Univ. of Technology, Wuhan (China). School of Science; Yang, Xiao-Qing [Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Dept.; Lee, Hung-Sui [Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Dept.; Qu, Deyang [Univ. of Wisconsin, Milwaukee, WI (United States). Collece of Engineering and Applied Science

    2015-08-01T23:59:59.000Z

    Oxygen reduction and oxygen evolution reactions were studied on graphite electrodes with different crystal orientations. The kinetics for the redox couple O2/O2•- are very fast, therefore no catalyst seems necessary to assist the charge transfer process. Apparently, the main source of the overpotential for the O2 reduction reaction is from mass diffusion. Li2O2 becomes soluble in non-aqueous electrolytes in the presence of the tetraethylammonium tetrafluoroborate additive. The soluble B-O22- ions can be oxidized electro-catalytically. The edge orientation of graphite demonstrates superior catalytic activity for the oxidation over basal orientation. The findings reveal an opportunity for recharging Li-air batteries efficiently and a new strategy of developing the catalyst for oxygen evolution reaction.

  17. Extracorporeal membrane oxygenation promotes long chain fatty...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    membrane oxygenation promotes long chain fatty acid oxidation in the immature swine heart in vivo. Extracorporeal membrane oxygenation promotes long chain fatty acid oxidation...

  18. Electrocatalytic Reactivity for Oxygen Reduction of Palladium...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Reactivity for Oxygen Reduction of Palladium-Modified Carbon Nanotubes Synthesized in Supercritical Fluid. Electrocatalytic Reactivity for Oxygen Reduction of Palladium-Modified...

  19. OXYGEN DIFFUSION IN HYPOSTOICHIOMETRIC URANIUM DIOXIDE

    E-Print Network [OSTI]

    Kim, Kee Chul

    2010-01-01T23:59:59.000Z

    Research Division OXYGEN DIFFUSION IN HYPOSTOICHIOMETRIC11905 -DISCLAIMER - OXYGEN DIFFUSION IN HYPOSTOICHIOMETRICc o n e e n i g woroxygen self-diffusion coefficient

  20. Formation, characterization and reactivity of adsorbed oxygen...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Formation, characterization and reactivity of adsorbed oxygen on BaOPt(111). Formation, characterization and reactivity of adsorbed oxygen on BaOPt(111). Abstract: The formation...

  1. Angling chromium to let oxygen through | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Angling chromium to let oxygen through Angling chromium to let oxygen through Released: September 10, 2014 New semiconducting material works at lower temperatures Scanning...

  2. Polycyclic Aromatic Triptycenes: Oxygen Substitution Cyclization Strategies

    E-Print Network [OSTI]

    VanVeller, Brett

    The cyclization and planarization of polycyclic aromatic hydrocarbons with concomitant oxygen substitution was achieved through acid catalyzed transetherification and oxygen-radical reactions. The triptycene scaffold ...

  3. Apparatus and process for separating hydrogen isotopes

    DOE Patents [OSTI]

    Heung, Leung K; Sessions, Henry T; Xiao, Xin

    2013-06-25T23:59:59.000Z

    The apparatus and process for separating hydrogen isotopes is provided using dual columns, each column having an opposite hydrogen isotopic effect such that when a hydrogen isotope mixture feedstock is cycled between the two respective columns, two different hydrogen isotopes are separated from the feedstock.

  4. Method for laser induced isotope enrichment

    DOE Patents [OSTI]

    Pronko, Peter P.; Vanrompay, Paul A.; Zhang, Zhiyu

    2004-09-07T23:59:59.000Z

    Methods for separating isotopes or chemical species of an element and causing enrichment of a desired isotope or chemical species of an element utilizing laser ablation plasmas to modify or fabricate a material containing such isotopes or chemical species are provided. This invention may be used for a wide variety of materials which contain elements having different isotopes or chemical species.

  5. Compelling Research Opportunities using Isotopes

    SciTech Connect (OSTI)

    None

    2009-04-23T23:59:59.000Z

    Isotopes are vital to the science and technology base of the US economy. Isotopes, both stable and radioactive, are essential tools in the growing science, technology, engineering, and health enterprises of the 21st century. The scientific discoveries and associated advances made as a result of the availability of isotopes today span widely from medicine to biology, physics, chemistry, and a broad range of applications in environmental and material sciences. Isotope issues have become crucial aspects of homeland security. Isotopes are utilized in new resource development, in energy from bio-fuels, petrochemical and nuclear fuels, in drug discovery, health care therapies and diagnostics, in nutrition, in agriculture, and in many other areas. The development and production of isotope products unavailable or difficult to get commercially have been most recently the responsibility of the Department of Energy's Nuclear Energy program. The President's FY09 Budget request proposed the transfer of the Isotope Production program to the Department of Energy's Office of Science in Nuclear Physics and to rename it the National Isotope Production and Application program (NIPA). The transfer has now taken place with the signing of the 2009 appropriations bill. In preparation for this, the Nuclear Science Advisory Committee (NSAC) was requested to establish a standing subcommittee, the NSAC Isotope Subcommittee (NSACI), to advise the DOE Office of Nuclear Physics. The request came in the form of two charges: one, on setting research priorities in the short term for the most compelling opportunities from the vast array of disciplines that develop and use isotopes and two, on making a long term strategic plan for the NIPA program. This is the final report to address charge 1. NSACI membership is comprised of experts from the diverse research communities, industry, production, and homeland security. NSACI discussed research opportunities divided into three areas: (1) medicine, pharmaceuticals, and biology, (2) physical sciences and engineering, and (3) national security and other applications. In each area, compelling research opportunities were considered and the subcommittee as a whole determined the final priorities for research opportunities as the foundations for the recommendations. While it was challenging to prioritize across disciplines, our order of recommendations reflect the compelling research prioritization along with consideration of time urgency for action as well as various geopolitical market issues. Common observations to all areas of research include the needs for domestic availability of crucial stable and radioactive isotopes and the education of the skilled workforce that will develop new advances using isotopes in the future. The six recommendations of NSACI reflect these concerns and the compelling research opportunities for potential new discoveries. The science case for each of the recommendations is elaborated in the respective chapters.

  6. Electrochemical Isotope Effect and Lithium Isotope Separation Jay R. Black,

    E-Print Network [OSTI]

    Mcdonough, William F.

    results showing a large lithium isotope separation due to electrodeposition. The fractionation is tunable lithium were plated from solutions of 1 M LiClO4 in propylene carbonate (PC) on planar nickel electrodes

  7. A lithium oxygen secondary battery

    SciTech Connect (OSTI)

    Semkow, K.W.; Sammells, A.F.

    1987-08-01T23:59:59.000Z

    In principle the lithium-oxygen couple should provide one of the highest energy densities yet investigated for advanced battery systems. The problem to this time has been one of identifying strategies for achieving high electrochemical reversibilities at each electrode under conditions where one might anticipate to also achieve long materials lifetimes. This has been addressed in recent work by us via the application of stabilized zirconia oxygen vacancy conducting solid electrolytes, for the effective separation of respective half-cell reactions.

  8. PUBLICATIONS ROBERT EVERETT CRISS 1999 Criss, R.E., Principles of Stable Isotope Distribution, Oxford University Press,

    E-Print Network [OSTI]

    of a rainfall-driven theoretical hydrograph compared to common models and observed data. Water Resources and the global power. Int. J. of Earth Science (Bykov Special Issue), 97, p. 241-244 Criss, R. E., (2008) Terrestrial oxygen isotope variations and their implications for planetary lithospheres. Rev. Mineral., 68, ch

  9. Novel hybrid isotope separation scheme and apparatus

    DOE Patents [OSTI]

    Maya, Jakob (Brookline, MA)

    1991-01-01T23:59:59.000Z

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which the specific isotope is to be isolated, radiating the gas with frequencies characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photoionization reaction of the desired isotope, and collecting the specific isotope ion by suitable ion collection means.

  10. Novel hybrid isotope separation scheme and apparatus

    DOE Patents [OSTI]

    Maya, J.

    1991-06-18T23:59:59.000Z

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which the specific isotope is to be isolated, radiating the gas with frequencies characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photoionization reaction of the desired isotope, and collecting the specific isotope ion by suitable ion collection means. 3 figures.

  11. Selective photoionisation of lutetium isotopes

    SciTech Connect (OSTI)

    D'yachkov, Aleksei B; Kovalevich, S K; Labozin, Valerii P; Mironov, Sergei M; Panchenko, Vladislav Ya; Firsov, Valerii A; Tsvetkov, G O; Shatalova, G G [National Research Centre 'Kurchatov Institute', Moscow (Russian Federation)

    2012-10-31T23:59:59.000Z

    A three-stage laser photoionisation scheme intended for enriching the {sup 176}Lu isotope from natural lutetium was considered. An investigation was made of the hyperfine structure of the second excited state 5d6s7s {yields} {sup 4}D{sub 3/2} with an energy of 37194 cm{sup -1} and the autoionisation state with an energy of 53375 cm{sup -1} of the {sup 176}Lu and {sup 175}Lu isotopes. The total electron momentum of the autoionisation level and the constant A of hyperfine magnetic interaction were determined. Due to a small value of the isotopic shift between {sup 176}Lu and {sup 175}Lu, appreciable selectivity of their separation may be achieved with individual hyperfine structure components. The first tentative enrichment of the 176Lu isotope was performed to a concentration of 60 % - 70 %. (laser applications and other topics in quantum electronics)

  12. Z .Physics of the Earth and Planetary Interiors 110 1999 191210 Oxygen in the Earth's core: a first-principles study

    E-Print Network [OSTI]

    Alfè, Dario

    -principles electronic structure calculations based on DFT have been used to study the thermodynamic, structural, structural and dynamical properties of solid and liquid materials, including liquid metals Z .Stich et al conditions. It is shown that earlier first-principles calculations indicating very large enthalpies

  13. Acetylation and glycation of fibrinogen in vitro occur at specific lysine residues in a concentration dependent manner: A mass spectrometric and isotope labeling study

    SciTech Connect (OSTI)

    Svensson, Jan, E-mail: jan.svensson@ki.se [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden) [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden); Bergman, Ann-Charlotte [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden)] [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Adamson, Ulf [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden)] [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden); Blombaeck, Margareta [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden)] [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Wallen, Hakan; Joerneskog, Gun [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden)] [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden)

    2012-05-04T23:59:59.000Z

    Highlights: Black-Right-Pointing-Pointer Fibrinogen was incubated in vitro with glucose or aspirin. Black-Right-Pointing-Pointer Acetylations and glycations were found at twelve lysine sites by mass spectrometry. Black-Right-Pointing-Pointer The labeling by aspirin and glucose occurred dose-dependently. Black-Right-Pointing-Pointer No competition between glucose and aspirin for binding to fibrinogen was found. -- Abstract: Aspirin may exert part of its antithrombotic effects through platelet-independent mechanisms. Diabetes is a condition in which the beneficial effects of aspirin are less prominent or absent - a phenomenon called 'aspirin resistance'. We investigated whether acetylation and glycation occur at specific sites in fibrinogen and if competition between glucose and aspirin in binding to fibrinogen occurs. Our hypothesis was that such competition might be one explanation to 'aspirin resistance' in diabetes. After incubation of fibrinogen in vitro with aspirin (0.8 mM, 24 h) or glucose (100 mM, 5-10 days), we found 12 modified sites with mass spectrometric techniques. Acetylations in the {alpha}-chain: {alpha}K191, {alpha}K208, {alpha}K224, {alpha}K429, {alpha}K457, {alpha}K539, {alpha}K562, in the {beta}-chain: {beta}K233, and in the {gamma}-chain: {gamma}K170 and {gamma}K273. Glycations were found at {beta}K133 and {gamma}K75, alternatively {gamma}K85. Notably, the lysine 539 is a site involved in FXIII-mediated cross-linking of fibrin. With isotope labeling in vitro, using [{sup 14}C-acetyl]salicylic acid and [{sup 14}C]glucose, a labeling of 0.013-0.084 and 0.12-0.5 mol of acetylated and glycated adduct/mol fibrinogen, respectively, was found for clinically (12.9-100 {mu}M aspirin) and physiologically (2-8 mM glucose) relevant plasma concentrations. No competition between acetylation and glycation could be demonstrated. Thus, fibrinogen is acetylated at several lysine residues, some of which are involved in the cross-linking of fibrinogen. This may mechanistically explain why aspirin facilitates fibrin degradation. We find no support for the idea that glycation of fibrin(ogen) interferes with acetylation of fibrinogen.

  14. Isotope production facility produces cancer-fighting actinium

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cancer therapy gets a boost from new isotope Isotope production facility produces cancer-fighting actinium A new medical isotope project shows promise for rapidly producing major...

  15. OXYGEN ADSORPTION ON NITROGEN CONTAINING CARBON SURFACES

    E-Print Network [OSTI]

    Truong, Thanh N.

    OXYGEN ADSORPTION ON NITROGEN CONTAINING CARBON SURFACES Alejandro Montoya, Jorge O. Gil, Fanor-rich site of the carbon basal plane of graphite and then, it dissociates into oxygen atoms.1,2 Oxygen atoms at the edge of the carbon surface can form covalent bonds with oxygen. These sites can chemisorb

  16. Flammability of selected heat resistant alloys in oxygen gas mixtures

    SciTech Connect (OSTI)

    Zawierucha, R.; McIlroy, K.; Million, J.F. [Praxair, Inc., Tonawanda, NY (United States)

    1995-12-31T23:59:59.000Z

    Within recent years, the use of oxygen has increased in applications where elevated temperatures and corrosion may be significant factors. In such situations, traditional alloys used in oxygen systems will not be adequate. Where alternative alloys must be utilized, based upon environmental requirements, it is essential that they may be characterized with respect to their ignition and combustion resistance in oxygen. Promoted ignition and promoted ignition-combustion are terms which have been used to describe a situation where a substance with low oxygen supports the combustion of a compatibility ignites and more ignition resistant material. In this paper, data will be presented on the promoted ignition-combustion behavior of selected heat resistant engineering alloys that may be considered for gaseous oxygen applications in severe environments. In this investigation, alloys have been evaluated via both flowing and static (fixed volume) approaches using a rod configuration. Oxygen-nitrogen gas mixtures with compositions ranging from approximately 40 to 99.7% oxygen at pressures of 3.55 to 34.6 MPa were used in the comparative studies.

  17. Measuring oxygen reduction/evolution reactions on the nanoscale

    SciTech Connect (OSTI)

    Kalinin, Sergei V [ORNL; Jesse, Stephen [ORNL; Kumar, Amit [ORNL; Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine; Ciucci, Francesco [Harvard-Smithsonian Center for Astrophysics

    2011-01-01T23:59:59.000Z

    The efficiency of fuel cells and metal-air batteries is significantly limited by the activation of oxygen reduction and evolution reactions (ORR/OER). Despite the well-recognized role of oxygen reaction kinetics on the viability of energy technologies, the governing mechanisms remain elusive and until now addressable only by macroscopic studies. This lack of nanoscale understanding precludes optimization of material architecture. Here we report direct measurements of oxygen reduction/evolution reactions and oxygen vacancy diffusion on oxygen-ion conductive solid surfaces with sub-10 nanometer resolution. In electrochemical strain microscopy (ESM), the biased scanning probe microscopy tip acts as a moving, electrocatalytically active probe exploring local electrochemical activity. The probe concentrates an electric field in a nanometer-scale volume of material, and bias-induced, picometer-level surface displacements provide information on local electrochemical processes. Systematic mapping of oxygen activity on bare and Pt-functionalized yttria-stabilized zirconia (YSZ) surfaces is demonstrated. This approach allows directly visualization of ORR/OER activation process at the triple-phase boundary, and can be extended to broad spectrum of oxygen-conductive and electrocatalytic materials.

  18. Infrared Spectroscopy and Stable Isotope Geochemistry of Hydrous Silicate Glasses

    SciTech Connect (OSTI)

    Stolper, Edward

    2007-03-05T23:59:59.000Z

    The focus of this DOE-funded project has been the study of volatile components in magmas and the atmosphere. Over the twenty-one year period of this project, we have used experimental petrology and stable isotope geochemistry to study the behavior and properties of volatile components dissolved in silicate minerals and melts and glasses. More recently, we have also studied the concentration and isotopic composition of CO2 in the atmosphere, especially in relation to air quality issues in the Los Angeles basin.

  19. Method and device for the determination of low concentrations of oxygen in carbonaceous materials

    DOE Patents [OSTI]

    Schultz, Hyman (Jefferson Boro, PA)

    1992-01-01T23:59:59.000Z

    Oxygen in carbonaceous materials is converted to carbon monoxide (CO) by pyrolyzing the material in a stream of oxygen-free helium. The CO is reacted with Ni.sup.63, a readioactive isotope of nickel, to form nickel tetracarbonyl (Ni.sup.63 (CO).sub.4) which is carried by the helium stream into a flow-through gas proportional counter. The quantity of Ni(CO).sub.4 is determined by the radioactivity of the gas as measured by the gas proportional counter. After exiting the flow through counter the Ni.sup.63 (CO).sub.4 is destroyed by exposing it to high temperatures. The Ni.sup.63 is retained within the apparatus while the CO is flushed from the system after being oxidized to carbon dioxide (CO.sub.2). The detection limit is estimated to be less than 1 part per billion oxygen for a 10 mg sample.

  20. Oxygen uptake of benthic systems

    E-Print Network [OSTI]

    Priebe, William Franklin

    1972-01-01T23:59:59.000Z

    mg/hr/sq m between standard and maximum mixing. Hanes and Irvine (23) made a determination of the effects of temperature on quiescent oxygen uptake rates by covering sludge with aerated water and allowing the supernatant to be totally de- pleted.... ECTROLTSIS STSTDI FOA MEMURIRC BOO. FIGURE 2. SWITCH ELECTROQE IN CONTACT WITH ELECTROIYTE. OXYGEN GENERATOR OFF. FIGURE 3. SWIICH ELECI'RODE NOT IN CONTACT' WITH -' ECTROLYTE. 0 0 0 a 0 0 0 ~ O0 0 o 0 0 o o 0 0 0 0 PIERRE A. HIGH SPEED NIXINC...

  1. Oxygen uptake of benthic systems 

    E-Print Network [OSTI]

    Priebe, William Franklin

    1972-01-01T23:59:59.000Z

    mg/hr/sq m between standard and maximum mixing. Hanes and Irvine (23) made a determination of the effects of temperature on quiescent oxygen uptake rates by covering sludge with aerated water and allowing the supernatant to be totally de- pleted.... ECTROLTSIS STSTDI FOA MEMURIRC BOO. FIGURE 2. SWITCH ELECTROQE IN CONTACT WITH ELECTROIYTE. OXYGEN GENERATOR OFF. FIGURE 3. SWIICH ELECI'RODE NOT IN CONTACT' WITH -' ECTROLYTE. 0 0 0 a 0 0 0 ~ O0 0 o 0 0 o o 0 0 0 0 PIERRE A. HIGH SPEED NIXINC...

  2. Nickel isotopes in stellar matter

    E-Print Network [OSTI]

    Jameel-Un Nabi

    2014-08-19T23:59:59.000Z

    Isotopes of nickel play a key role during the silicon burning phase up to the presupernova phase of massive stars. Electron capture rates on these nickel isotopes are also important during the phase of core contraction. I present here the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions for key nickel isotopes. The calculation is performed within the frame-work of pn-QRPA model. A judicious choice of model parameters, specially of the Gamow-Teller strength parameters and the deformation parameter, resulted in a much improved calculation of GT strength functions. The excited state GT distributions are much different from the corresponding ground-state distributions resulting in a failure of the Brink's hypothesis. The electron capture and positron decay rates on nickel isotopes are also calculated within the framework of pn-QRPA model relevant to the presupernova evolution of massive stars. The electron capture rates on odd-A isotopes of nickel are shown to have dominant contributions from parent excited states during as early as silicon burning phases. Comparison is being made with the large scale shell model calculation. During the silicon burning phases of massive stars the electron capture rates on $^{57,59}$Ni are around an order of magnitude bigger than shell model rates and can bear consequences for core-collapse simulators.

  3. Isotopic consequences of consumer food choice: Hydrogen and oxygen stable isotope ratios in foods from fast food restaurants versus supermarkets

    E-Print Network [OSTI]

    Ehleringer, Jim

    . Erkkila a,b , Thure E. Cerling a,b,c , James R. Ehleringer a,b a Department of Biology, University of Utah) regions of the USA (Leff, Ramankutty, & Foley, 2004; Monfreda, Ramankutty, & Foley, 2008). The result can

  4. Identification of sources of lead exposure in French children by lead isotope analysis: a cross-

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Identification of sources of lead exposure in French children by lead isotope analysis: a cross://www.ehjournal.net/content/10/1/75 (28 August 2011) #12;RESEARCH Open Access Identification of sources of lead exposure in French children by lead isotope analysis: a cross- sectional study Youssef Oulhote1,2,3* , Barbara Le Bot

  5. Carbon isotope evidence for recent climate-related enhancement of CO2 assimilation and peat accumulation

    E-Print Network [OSTI]

    Carbon isotope evidence for recent climate-related enhancement of CO2 assimilation and peat change. In this study, peat cores up to 2 m in depth from four moss banks on Signy Island were used included radiocarbon dating (to determine peat accumulation rates) and stable carbon isotope composition

  6. Isotopically Enriched Films and Nanostructures by Ultrafast Pulsed Laser Deposition

    SciTech Connect (OSTI)

    Peter Pronko

    2004-12-13T23:59:59.000Z

    This project involved a systematic study to apply newly discovered isotopic enrichment effects in laser ablation plumes to the fabrication of isotopically engineered thin films, superlattices, and nanostructures. The approach to this program involved using ultrafast lasers as a method for generating ablated plasmas that have preferentially structured isotopic content in the body of the ablation plasma plumes. In examining these results we have attempted to interpret the observations in terms of a plasma centrifuge process that is driven by the internal electro-magnetic fields of the plasma itself. The research plan involved studying the following phenomena in regard to the ablation plume and the isotopic mass distribution within it: (1) Test basic equations of steady state centrifugal motion in the ablation plasma. (2) Investigate angular distribution of ions in the ablation plasmas. (3) Examine interactions of plasma ions with self-generated magnetic fields. (3) Investigate ion to neutral ratios in the ablation plasmas. (5) Test concepts of plasma pumping. (6) Fabricate isotopically enriched nanostructures.

  7. Online Catalog of Isotope Products from DOE's National Isotope Development Center

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The National Isotope Development Center (NIDC) interfaces with the User Community and manages the coordination of isotope production across the facilities and business operations involved in the production, sale, and distribution of isotopes. A virtual center, the NIDC is funded by the Isotope Development and Production for Research and Applications (IDPRA) subprogram of the Office of Nuclear Physics in the U.S. Department of Energy Office of Science. The Isotope subprogram supports the production, and the development of production techniques of radioactive and stable isotopes that are in short supply for research and applications. Isotopes are high-priority commodities of strategic importance for the Nation and are essential for energy, medical, and national security applications and for basic research; a goal of the program is to make critical isotopes more readily available to meet domestic U.S. needs. This subprogram is steward of the Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL), the Brookhaven Linear Isotope Producer (BLIP) facility at BNL, and hot cell facilities for processing isotopes at ORNL, BNL and LANL. The subprogram also coordinates and supports isotope production at a suite of university, national laboratory, and commercial accelerator and reactor facilities throughout the Nation to promote a reliable supply of domestic isotopes. The National Isotope Development Center (NIDC) at ORNL coordinates isotope production across the many facilities and manages the business operations of the sale and distribution of isotopes.

  8. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect (OSTI)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2003-01-01T23:59:59.000Z

    In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Processing of perovskites of LSC, LSF and LSCF composition for evaluation of mechanical properties as a function of environment are begun. The studies are to be in parallel with LSFCO composition to characterize the segregation of cations and slow crack growth in environmental conditions. La{sub 1-x}Sr{sub x}FeO{sub 3-d} has also been characterized for paramagnetic ordering at room temperature and the evolution of magnetic moments as a function of temperature are investigated. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport.

  9. Oxygen Enriched Combustion System Performance Study

    E-Print Network [OSTI]

    Chen, S. L.; Kwan, Y.; Abele, A. R.; Silver, L. S.; Kobayashi, H.

    determined with detailed measurements. The detailed measurements, including furnace gas temperature profile, total and radiant heat flux, will be integrated and evaluated with a numerical heat transfer model. The model will then be used to extrapolate...

  10. Isotope Development & Production | Nuclear Science | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Medical Radioisotope Radiochemical Separation & Processing Strategic Isotope Production Super Heavy Element Discovery Nuclear Security Science & Technology Nuclear Systems...

  11. (Carbon isotope fractionation in plants): Annual technical progress report

    SciTech Connect (OSTI)

    O'Leary, M.H.

    1988-01-01T23:59:59.000Z

    Plants fractionate carbon isotopes during photosynthesis in ways which reflect photosynthetic pathway and environment. The fractionation is product of contributions from diffusion, carboxylation and other factors which can be understood using models which have been developed in our work. The object of our work is to use this fractionation to learn about the factors which control the efficiency of photosynthesis. Unlike previous studies, we do not rely principally on combustion methods, but instead develop more specific methods with substantially higher resolving power. We have recently developed a new short-term method for studying carbon isotope fractionation which promises to provide a level of detail about temperature, species, and light intensity effects on photosynthesis which has not been available until now. We are studying the isotopic compositions of metabolites (particularly aspartic acid) in C/sub 3/ plants in order to determine the role of phosphoenolpyruvate carboxylase in C/sub 3/ photosynthesis. We are studying the relative roles of diffusion and carboxylation in nocturnal CO/sub 2/ fixation in CAM plants. We are studying the use of isotopic content as an index of water-use efficiency in C/sub 3/ plants. We are developing new methods for studying carbon metabolism in plants. 3 refs

  12. Isotopes of helium, hydrogen, and carbon as groundwater tracers in aquifers along the Colorado River

    E-Print Network [OSTI]

    Haber, Samuel Ainsworth

    2009-01-01T23:59:59.000Z

    composition of radiogenic helium and its use to studyH. , Lupton, J.E. (1981) Helium-3 and mantle volatiles inand Izbicki, J.A. (2003). Helium isotope studies in the

  13. Ultimate Isotope Precision for Carbonates Thermo Scientific

    E-Print Network [OSTI]

    Lachniet, Matthew S.

    Ultimate Isotope Precision for Carbonates Thermo Scientific KIEL IV Carbonate Device Part of Thermo integration cycle Ultimate Isotope Precision for Carbonates The Thermo Scientific KIEL IV Carbonate DeviceV Thermo Scientific MAT 253 or the 3-kV DELTA V isotope ratio mass spectrometer meets the requirements

  14. Natural mercury isotope variation in coal deposits and organic soils

    SciTech Connect (OSTI)

    Abir, Biswas; Joel D. Blum; Bridget A. Bergquist; Gerald J. Keeler; Zhouqing Xie [University of Michigan, Ann Arbor, MI (United States). Department of Geological Sciences

    2008-11-15T23:59:59.000Z

    There is a need to distinguish among sources of Hg to the atmosphere in order to more fully understand global Hg pollution. In this study we investigate whether coal deposits within the United States, China, and Russia-Kazakhstan, which are three of the five greatest coal-producing regions, have diagnostic Hg isotopic fingerprints that can be used to discriminate among Hg sources. We also investigate the Hg isotopic composition of modern organic soil horizons developed in areas distant from point sources of Hg in North America. Mercury stored in coal deposits displays a wide range of both mass dependent fractionation and mass independent fractionation. {delta}{sup 202}Hg varies in coals by 3{per_thousand} and {Delta}{sup 201}Hg varies by 0.9{per_thousand}. Combining these two Hg isotope signals results in what may be a unique isotopic 'fingerprint' for many coal deposits. Mass independent fractionation of mercury has been demonstrated to occur during photochemical reactions of mercury. This suggests that Hg found in most coal deposits was subjected to photochemical reduction near the Earth's surface prior to deposition. The similarity in MDF and MIF of modern organic soils and coals from North America suggests that Hg deposition from coal may have imprinted an isotopic signature on soils. This research offers a new tool for characterizing mercury inputs from natural and anthropogenic sources to the atmosphere and provides new insights into the geochemistry of mercury in coal and soils. 35 refs., 2 figs., 1 tab.

  15. $?$-decay of key titanium isotopes in stellar environment

    E-Print Network [OSTI]

    Jameel-Un Nabi; Irgaziev Bakhadir

    2011-08-04T23:59:59.000Z

    Amongst iron regime nuclei, $\\beta$-decay rates on titanium isotopes are considered to be important during the late phases of evolution of massive stars. The key $\\beta$-decay isotopes during presupernova evolution were searched from available literature and a microscopic calculation of the decay rates were performed using the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. As per earlier simulation results electron capture and $\\beta$-decay on certain isotopes of titanium are considered to be important for the presupernova evolution of massive stars. Earlier the stellar electron capture rates and neutrino energy loss rates due to relevant titanium isotopes were presented. In this paper we finally present the $\\beta$-decay rates of key titanium isotopes in stellar environment. The results are also compared against previous calculations. The pn-QRPA $\\beta$-decay rates are bigger at high stellar temperatures and smaller at high stellar densities compared to the large scale shell model results. This study can prove useful for the core-collapse simulators.

  16. The use of carbon stable isotope ratios in drugs characterization

    SciTech Connect (OSTI)

    Magdas, D. A., E-mail: gabriela.cristea@itim-cj.ro; Cristea, G., E-mail: gabriela.cristea@itim-cj.ro; Bot, A., E-mail: gabriela.cristea@itim-cj.ro; Mirel, V., E-mail: gabriela.cristea@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania)

    2013-11-13T23:59:59.000Z

    Isotopic Ratio Mass Spectrometry (IRMS) is an effective toll to be used for drug product authentication. The isotopic composition could be used to assist in the differentiation between batches of drugs and assist in the identification of counterfeit materials on the market. Only two factors affect the isotopic ratios in pharmaceutical components: the isotopic composition of the raw materials and the synthetic processes performed upon them. Counterfeiting of pharmaceutical drugs threatens consumer confidence in drug products companies' economical well-being. In this preliminary study, the analyzed samples consist in two types of commercially available analgesics, which were purchases from Romanian pharmacies. Differences in ?{sup 13}C between batches from ?29.7 to ?31.6% were observed, demonstrating that this method can be used to differentiate among individual drug batches and subsequently identify counterfeits on the market. On the other hand, carbon isotopic ratios differences among producers were recorded, the variations being between ?31.3 to ?34.9% for the same type of analgesic, but from different manufactures.

  17. Methods for separating oxygen from oxygen-containing gases

    DOE Patents [OSTI]

    Mackay, Richard (Lafayette, CO); Schwartz, Michael (Boulder, CO); Sammells, Anthony F. (Boulder, CO)

    2000-01-01T23:59:59.000Z

    This invention provides mixed conducting metal oxides particularly useful for the manufacture of catalytic membranes for gas-phase oxygen separation processes. The materials of this invention have the general formula: A.sub.x A'.sub.x A".sub.2-(x+x') B.sub.y B'.sub.y B".sub.2-(y+y') O.sub.5+z ; where x and x' are greater than 0; y and y' are greater than 0; x+x' is less than or equal to 2; y+y' is less than or equal to 2; z is a number that makes the metal oxide charge neutral; A is an element selected from the f block lanthanide elements; A' is an element selected from Be, Mg, Ca, Sr, Ba and Ra; A" is an element selected from the f block lanthanides or Be, Mg, Ca, Sr, Ba and Ra; B is an element selected from the group consisting of Al, Ga, In or mixtures thereof; and B' and B" are different elements and are independently selected from the group of elements Mg or the d-block transition elements. The invention also provides methods for oxygen separation and oxygen enrichment of oxygen deficient gases which employ mixed conducting metal oxides of the above formula. Examples of the materials used for the preparation of the membrane include A.sub.x Sr.sub.x' B.sub.y Fe.sub.y' Co.sub.2-(y+y') O.sub.5+z, where x is about 0.3 to about 0.5, x' is about 1.5 to about 1.7, y is 0.6, y' is between about 1.0 and 1.4 and B is Ga or Al.

  18. The Role of Oxygen in Coal Gasification 

    E-Print Network [OSTI]

    Klosek, J.; Smith, A. R.; Solomon, J.

    1986-01-01T23:59:59.000Z

    Air Products supplies oxygen to a number of coal gasification and partial oxidation facilities worldwide. At the high operating pressures of these processes, economics favor the use of 90% and higher oxygen purities. The effect of inerts...

  19. Microbial oceanography of anoxic oxygen minimum zones

    E-Print Network [OSTI]

    Ulloa, Osvaldo

    Vast expanses of oxygen-deficient and nitrite-rich water define the major oxygen minimum zones (OMZs) of the global ocean. They support diverse microbial communities that influence the nitrogen economy of the oceans, ...

  20. Microchemical systems for singlet oxygen generation

    E-Print Network [OSTI]

    Hill, Tyrone F. (Tyrone Frank), 1980-

    2008-01-01T23:59:59.000Z

    Chemical Oxygen-Iodine Lasers (COIL) are a technology of interest for industrial and military audiences. COILs are flowing gas lasers where the gain medium of iodine atoms is collisionally pumped by singlet delta oxygen ...

  1. Imaging Oxygen Molecules Up Close | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Imaging Oxygen Molecules Up Close Imaging Oxygen Molecules Up Close Released: March 20, 2011 ARRA-enabled upgrades enhance research capabilities STM images of the same TiO2(110)...

  2. Rare Isotopes in Cosmic Explosions and Accelerators on Earth

    ScienceCinema (OSTI)

    Hendrik Schatz

    2010-01-08T23:59:59.000Z

    Rare isotopes are nature?s stepping stones to produce the heavy elements, and they are produced in large quantities in stellar explosions. Despite their fleeting existence, they shape the composition of the universe and the observable features of stellar explosions. The challenge for nuclear science is to produce and study the very same rare isotopes so as to understand the origin of the elements and a range of astronomical observations. I will review the progress that has been made to date in astronomy and nuclear physics, and the prospects of finally addressing many of the outstanding issues with the future Facility for Rare Isotope Beams (FRIB), which DOE will build at Michigan State University.

  3. Electron spin decoherence in isotope-enriched silicon

    E-Print Network [OSTI]

    Wayne M. Witzel; Malcolm S. Carroll; Andrea Morello; Lukasz Cywinski; S. Das Sarma

    2010-10-27T23:59:59.000Z

    Silicon is promising for spin-based quantum computation because nuclear spins, a source of magnetic noise, may be eliminated through isotopic enrichment. Long spin decoherence times, $T_2$, have been measured in isotope-enriched silicon but come far short of the $T_2 = 2 T_1$ limit. The effect of nuclear spins on $T_2$ is well established. However, the effect of background electron spins from ever present residual phosphorus impurities in silicon can also produce significant decoherence. We study spin decoherence decay as a function of donor concentration, $^{29}$Si concentration, and temperature using cluster expansion techniques specifically adapted to the problem of a sparse dipolarly coupled electron spin bath. Our results agree with the existing experimental spin echo data in Si:P and establish the importance of background dopants as the ultimate decoherence mechanism in isotope-enriched silicon.

  4. Isotopic Scaling and the Symmetry Energy in Spectator Fragmentation

    E-Print Network [OSTI]

    Auger, G; Begemann-Blaich, M L; Bellaize, N; Bittiger, R; Bocage, F; Borderie, B; Bougault, R; Bouriquet, B; Charvet, J L; Chbihi, A; Dayras, R; Durand, D; Frankland, J D; Galíchet, E; Gourio, D; Guinet, D; Hudan, S; Imme, G; Lautesse, P; Lavaud, F; Legrain, R; López, O; Lynen, U; Müller, W F J; Nalpas, L; Orth, H; Plagnol, E; Raciti, G; Rosato, E; Saija, A; Schwarz, C; Seidel, W; Sfienti, C; Tamain, B; Trautmann, W; Trzcinski, A; Turzó, K; Vient, E; Vigilante, M; Volant, C; Zwieglinski, B; Botvina, A S; The INDRA Collaboration

    2004-01-01T23:59:59.000Z

    Isotopic effects in the fragmentation of excited target residues following collisions of $^{12}$C on $^{112,124}$Sn at incident energies of 300 and 600 MeV per nucleon were studied with the INDRA 4$\\pi$ detector. The measured yield ratios for light particles and fragments with atomic number $Z \\leq$ 5 obey the exponential law of isotopic scaling. The deduced scaling parameters decrease with increasing centrality to values as low as $\\alpha = 0.25 \\pm 0.02$ for the central event group at 600 MeV per nucleon. Symmetry term coefficients, deduced from these data within the statistical description of isotopic scaling, are near $\\gamma =$ 25 MeV for peripheral and $\\gamma <$ 10 MeV for central collisions.

  5. Shape co-existence and parity doublet in Zr isotopes

    E-Print Network [OSTI]

    Bharat Kumar

    2014-12-05T23:59:59.000Z

    We studied the ground and excited states properties for Zr isotopes starting^M from proton to neutron drip-lines using the relativistic and non-relativistic mean field formalisms with BCS and Bogolyubov pairing. The celebrity NL3 and SLy4 parameter sets are used in the calculations. We find spherical ground and low-lying^M superdeformed excited states in most of the isotopes. Several couples of^M $\\Omega^{\\pi}=1/2^{\\pm}$ parity doublets configurations are found,^M while analyzing the single-particle energy levels of the superdeformed ^M configurations.

  6. The Mechanisms of Oxygen Reduction and Evolution Reactions in...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The Mechanisms of Oxygen Reduction and Evolution Reactions in Nonaqueous Lithium-Oxygen Batteries. The Mechanisms of Oxygen Reduction and Evolution Reactions in Nonaqueous...

  7. Type Ia supernovae from exploding oxygen-neon white dwarfs

    E-Print Network [OSTI]

    Marquardt, Kai S; Ruiter, Ashley J; Seitenzahl, Ivo R; Ohlmann, Sebastian T; Kromer, Markus; Pakmor, Ruediger; Roepke, Friedrich K

    2015-01-01T23:59:59.000Z

    The progenitor problem of Type Ia supernovae (SNe Ia) is still unsolved. Most of these events are thought to be explosions of carbon-oxygen (CO) white dwarfs (WDs), but for many of the explosion scenarios, particularly those involving the externally triggered detonation of a sub-Chandrasekhar mass WD (sub-M Ch WD), there is also a possibility of having an oxygen-neon (ONe) WD as progenitor. We simulate detonations of ONe WDs and calculate synthetic observables from these models. The results are compared with detonations in CO WDs of similar mass and observational data of SNe Ia. We perform hydrodynamic explosion simulations of detonations in initially hydrostatic ONe WDs for a range of masses below the Chandrasekhar mass (M Ch), followed by detailed nucleosynthetic postprocessing with a 384-isotope nuclear reaction network. The results are used to calculate synthetic spectra and light curves, which are then compared with observations of SNe Ia. We also perform binary evolution calculations to determine the nu...

  8. Isotope specific resolution recovery image reconstruction in high resolution PET imaging

    SciTech Connect (OSTI)

    Kotasidis, Fotis A. [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom)] [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom); Angelis, Georgios I. [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia)] [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia); Anton-Rodriguez, Jose; Matthews, Julian C. [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom)] [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom); Reader, Andrew J. [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom)] [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland) [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland); Geneva Neuroscience Centre, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30 001, Groningen 9700 RB (Netherlands)

    2014-05-15T23:59:59.000Z

    Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution recovery image reconstruction. The benefits are expected to be more substantial for more energetic positron emitting isotopes such as Oxygen-15 and Rubidium-82.

  9. Oxygen Distribution in the Macaque Retina Jameel Ahmed* Rod D. Braun,^ Robert Dunn, Jr. * and Robert A. Linsenmeier*X

    E-Print Network [OSTI]

    Linsenmeier, Robert

    Oxygen Distribution in the Macaque Retina Jameel Ahmed* Rod D. Braun,^ Robert Dunn, Jr. * and Robert A. Linsenmeier*X Purpose. Oxygen distribution was characterized in the macaque retina, which is more like the human retina than others studied previously. Methods. Profiles of oxygen tension (Po2

  10. Composite oxygen ion transport element

    DOE Patents [OSTI]

    Chen, Jack C. (Getzville, NY); Besecker, Charles J. (Batavia, IL); Chen, Hancun (Williamsville, NY); Robinson, Earil T. (Mentor, OH)

    2007-06-12T23:59:59.000Z

    A composite oxygen ion transport element that has a layered structure formed by a dense layer to transport oxygen ions and electrons and a porous support layer to provide mechanical support. The dense layer can be formed of a mixture of a mixed conductor, an ionic conductor, and a metal. The porous support layer can be fabricated from an oxide dispersion strengthened metal, a metal-reinforced intermetallic alloy, a boron-doped Mo.sub.5Si.sub.3-based intermetallic alloy or combinations thereof. The support layer can be provided with a network of non-interconnected pores and each of said pores communicates between opposite surfaces of said support layer. Such a support layer can be advantageously employed to reduce diffusion resistance in any type of element, including those using a different material makeup than that outlined above.

  11. Catalyst containing oxygen transport membrane

    DOE Patents [OSTI]

    Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

    2012-12-04T23:59:59.000Z

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  12. Effects of oxygen on fracturing fluids

    SciTech Connect (OSTI)

    Walker, M.L.; Shuchart, C.E.; Yaritz, J.G.; Norman, L.R.

    1995-11-01T23:59:59.000Z

    The stability of polysaccharide gels at high temperature is limited by such factors as pH, mechanical degradation, and oxidants. Oxygen is unavoidably placed in fracturing fluids through dissolution of air. To prevent premature degradation of the fracturing fluid by this oxidant, oxygen scavengers are commonly used. In this paper, the effects of oxygen and various oxygen scavengers on gel stability will be presented. Mechanical removal of oxygen resulted in surprisingly stable fracturing gels at 275 F. However, chemical removal of oxygen gave mixed results. Test data from sodium thiosulfate, sodium sulfite, and sodium erythorbate used as oxygen scavengers/gel stabilizers showed that the efficiency of oxygen removal from gels did not directly coincide with the viscosity retention of the gel, and large excesses of additives were necessary to provide optimum gel stabilization. The inability of some oxygen scavengers to stabilize the gel was the result of products created from the interaction of oxygen with the oxygen scavenger, which in turn, produced species that degraded the gel. The ideal oxygen scavenger should provide superior gel stabilization without creating detrimental side reaction products. Of the materials tested, sodium thiosulfate appeared to be the most beneficial.

  13. Oxygen Detection via Nanoscale Optical Indicators

    E-Print Network [OSTI]

    Ghosh, Ruby N.

    Oxygen Detection via Nanoscale Optical Indicators Ruby N. Ghosh Dept. of Physics Michigan State University East Lansing, MI, USA weekschr@msu.edu Abstract--Oxygen plays a ubiquitous role in terrestrial developed an optical technique for monitoring oxygen in both gas and liquid phases utilizing nanoscale metal

  14. 8, 22252248, 2008 Detection of oxygen

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 8, 2225­2248, 2008 Detection of oxygen emission related to spring bloom H. Yamagishi et al Chemistry and Physics Discussions Detection of regional scale sea-to-air oxygen emission related to spring bloom near Japan by using in-situ measurements of atmospheric oxygen/nitrogen ratio H. Yamagishi 1 , Y

  15. MIXING AND TRANSPORT OF SHORT-LIVED AND STABLE ISOTOPES AND REFRACTORY GRAINS IN PROTOPLANETARY DISKS

    SciTech Connect (OSTI)

    Boss, Alan P., E-mail: boss@dtm.ciw.edu [Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States)

    2013-08-10T23:59:59.000Z

    Analyses of primitive meteorites and cometary samples have shown that the solar nebula must have experienced a phase of large-scale outward transport of small refractory grains as well as homogenization of initially spatially heterogeneous short-lived isotopes. The stable oxygen isotopes, however, were able to remain spatially heterogeneous at the {approx}6% level. One promising mechanism for achieving these disparate goals is the mixing and transport associated with a marginally gravitationally unstable (MGU) disk, a likely cause of FU Orionis events in young low-mass stars. Several new sets of MGU models are presented that explore mixing and transport in disks with varied masses (0.016 to 0.13 M{sub Sun }) around stars with varied masses (0.1 to 1 M{sub Sun }) and varied initial Q stability minima (1.8 to 3.1). The results show that MGU disks are able to rapidly (within {approx}10{sup 4} yr) achieve large-scale transport and homogenization of initially spatially heterogeneous distributions of disk grains or gas. In addition, the models show that while single-shot injection heterogeneity is reduced to a relatively low level ({approx}1%), as required for early solar system chronometry, continuous injection of the sort associated with the generation of stable oxygen isotope fractionations by UV photolysis leads to a sustained, relatively high level ({approx}10%) of heterogeneity, in agreement with the oxygen isotope data. These models support the suggestion that the protosun may have experienced at least one FU Orionis-like outburst, which produced several of the signatures left behind in primitive chondrites and comets.

  16. Oxygen permeation in bismuth-based materials part I: Sintering and oxygen permeation fluxes

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Oxygen permeation in bismuth-based materials part I: Sintering and oxygen permeation fluxes E;2 Abstract Oxygen permeation measurements were performed on two layered bismuth based oxide ceramics. Oxygen permeability for these systems was compared to permeability of the cubic fluorite type structure

  17. Singlet Oxygen Singlet oxygen generation and detection are growing fields with applications in such areas as

    E-Print Network [OSTI]

    Wells, Mathew G. - Department of Physical and Environmental Sciences, University of Toronto

    Singlet Oxygen Singlet oxygen generation and detection are growing fields with applications in such areas as cancer treatment, photosensitized oxidations, and biomolecular degradation. Ground state oxygen state of an oxygen molecule is a singlet state, which can readily react with other singlet molecules

  18. Lycopene cyclase paralog CruP protects against reactive oxygen species in oxygenic

    E-Print Network [OSTI]

    Wurtzel, Eleanore

    , quenching singlet oxygen generated during the water-splitting process of photo- synthesis (10, 11). VariousLycopene cyclase paralog CruP protects against reactive oxygen species in oxygenic photosynthetic cyclase. Instead, we show that CruP aids in preventing accumulation of reactive oxygen species (ROS

  19. Experimental Effects of Atomic Oxygen on the Development of an Electric Discharge Oxygen Iodine Laser

    E-Print Network [OSTI]

    Carroll, David L.

    state I. Conventionally, a two-phase (gas-liquid) chemistry singlet oxygen generator (SOG) producesExperimental Effects of Atomic Oxygen on the Development of an Electric Discharge Oxygen Iodine of the electric discharge iodine laser continues, the role of oxygen atoms downstream of the discharge region

  20. Achievements in testing of the MGA and FRAM isotopic software codes under the DOE/NNSA-IRSN cooperation of gamma-ray isotopic measurement systems

    SciTech Connect (OSTI)

    Vo, Duc [Los Alamos National Laboratory; Wang, Tzu - Fang [LLNL; Funk, Pierre [IRSN; Weber, Anne - Laure [IRSN; Pepin, Nicolas [IRSN; Karcher, Anna [IRSN

    2009-01-01T23:59:59.000Z

    DOE/NNSA and IRSN collaborated on a study of gamma-ray instruments and analysis methods used to perform isotopic measurements of special nuclear materials. The two agencies agreed to collaborate on the project in response to inconsistencies that were found in the various versions of software and hardware used to determine the isotopic abundances of uranium and plutonium. IRSN used software developed internally to test the MGA and FRAM isotopic analysis codes for criteria used to stop data acquisition. The stop-criterion test revealed several unusual behaviors in both the MGA and FRAM software codes.

  1. Hydrogen absorption characteristics of oxygen-stabilized rare-earth iron intermetallic compounds

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Hydrogen absorption characteristics of oxygen-stabilized rare-earth iron intermetallic compounds M Abstract. -- The thermal behavior of oxygen-stabilized RjFegO^-hydrogen (R = Y, Dy, Ho) systems was studied decade to the study of the hydrogenation characte- ristics of a variety of intermetallic compounds, our

  2. Blast furnace injection of massive quantities of coal with enriched air or pure oxygen

    SciTech Connect (OSTI)

    Ponghis, N.; Dufresne, P.; Vidal, R.; Poos, A. (Center de Recherches Metallurgiques, Liege (Belgium))

    1993-01-01T23:59:59.000Z

    An extensive study of the phenomena associated with the blast furnace injection of massive quantities of coal is described. Trials with conventional lances or oxy-coal injectors and hot blast at different oxygen contents - up to 40% - or with cold pure oxygen were realized at coal to oxygen ratios corresponding to a range of 150 to 440 kg. Pilot scale rigs, empty or filled with coke, as well as industrial blast furnaces were utilized.

  3. The structure of oxygen difluoride and an attempted preparation of cyanogen fluoride

    E-Print Network [OSTI]

    Hilton, Albert Ray

    1959-01-01T23:59:59.000Z

    ...................................................... 45 Figure 5. A Graphical Determination of the Fluorine Carbon Force Constant for FCN ...................... . . . ............ 46 Page vi ABSTRACT The molecular structure of oxygen difluoride (OF2 ) gas was studied by a standard microwave... components, where J is the total angular momentum quantum number of the initial state. 11 EXPERIMENTAL PROCEDURE 1. Preparation of Oxygen Difluoride Oxygen difluoride was prepared by passing fluorine gas through a cold, dilute, aqueous solution of sodium...

  4. 137Cs Activities and 135Cs/137Cs Isotopic Ratios at Idaho National Laboratory: A Case Study in Environmental Nuclear Forensic Analysis

    SciTech Connect (OSTI)

    Mathew S Snow; Morgan Kelley; Darin C. Snyder; James E. Delmore; Sue B. Clark

    2015-01-01T23:59:59.000Z

    Abstract is still in progress. Below is the current outline: -Some statement regarding how Cs can be useful for nuclear forensic analysis of environmental samples. -Then some other statement stating how the SDA provides an excellent case study for such an analysis. -137Cs concentration patterns suggest that the 137Cs came from localized releases in the near vicinity of the SDA, while observations of thermal 135Cs/137Cs ratios suggests some contribution from thermal fission product waste buried within the SDA. -137Cs activity patterns, combined with 135Cs/137Cs ratios, known Cs environmental chemistry, and historical data, suggest the Cs was most likely released from Pit 9 and Trench 48 during the 1969 flood. -Knowledge of the release event and excavations narrows the possible window for waste disposed of at SDA to 5 months (Trench 48) to 1.2 years (Pit 9). -Only 3 waste generators disposed of waste during this timeframe, however, as Rocky Flats Site did not generate any appreciable 137Cs waste, and as best estimates suggest that the INL disposed 2000 times as much non-actinide waste at the SDA than off-site processes, INL related operations are determined to be the most likely contributor to the observed Cs contamination. -While 135Cs/137Cs ratios have the potential to reveal information regarding the reactor design and operating conditions which led to the fission event, the large number of different INL reactors which most likely contributed to waste within Trench 48 and Pit 9, combined with evidence of a mixture of thermal and fast fission product Cs (most likely originating from global + regional fallout) precludes the ability to further refine the 135Cs/137Cs ratios. -However, at other sites which do not contain such large quantities of highly diverse contamination, secondary nuclide monitors which have similar environmental mobilities to Cs (such as Pu or Sr) might enable correction for the quantity of fallout within samples.

  5. Oxygen abundance in the Sloan Digital Sky Survey

    E-Print Network [OSTI]

    F. Shi; X. Kong; F. Z. Cheng

    2006-03-10T23:59:59.000Z

    We present two samples of $\\hii$ galaxies from the Sloan Digital Sky Survey (SDSS) spectroscopic observations data release 3. The electron temperatures($T_e$) of 225 galaxies are calculated with the photoionized $\\hii$ model and $T_e$ of 3997 galaxies are calculated with an empirical method. The oxygen abundances from the $T_e$ methods of the two samples are determined reliably. The oxygen abundances from a strong line metallicity indicator, such as $R_{23}$, $P$, $N2$, and $O3N2$, are also calculated. We compared oxygen abundances of $\\hii$ galaxies obtained with the $T_e$ method, $R_{23}$ method, $P$ method, $N2$ method, and $O3N2$method. The oxygen abundances derived with the $T_e$ method are systematically lower by $\\sim$0.2 dex than those derived with the $R_{23}$ method, consistent with previous studies based on $\\hii$ region samples. No clear offset for oxygen abundance was found between $T_e$ metallicity and $P$, $N2$ and $O3N2$ metallicity. When we studied the relation between N/O and O/H, we found that in the metallicity regime of $\\zoh > 7.95$, the large scatter of the relation can be explained by the contribution of small mass stars to the production of nitrogen. In the high metallicity regime, $\\zoh > 8.2$, nitrogen is primarily a secondary element produced by stars of all masses.

  6. Foraging Ecology of Green Turtles (Chelonia mydas) on the Texas Coast, as Determined by Stable Isotope Analysis

    E-Print Network [OSTI]

    Gorga, Catherine Concetta Theresa

    2011-10-21T23:59:59.000Z

    FORAGING ECOLOGY OF GREEN TURTLES (Chelonia mydas) ON THE TEXAS COAST, AS DETERMINED BY STABLE ISOTOPE ANALYSIS A Thesis by CATHERINE CONCETTA THERESA GORGA Submitted to the Office of Graduate Studies of Texas A&M University... Coast, as Determined by Stable Isotope Analysis Copyright 2010 Catherine Concetta Theresa Gorga FORAGING ECOLOGY OF GREEN TURTLES (Chelonia mydas) ON THE TEXAS COAST, AS DETERMINED BY STABLE ISOTOPE ANALYSIS A Thesis by CATHERINE...

  7. On the origin of the giant isotopic effect of hydrogen on the magnetic properties of YFe2A4.2 (A 5 H, D): A high pressure study

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    in room-temperature magnetic refrigeration has appeared, which promises several advantages over convenOn the origin of the giant isotopic effect of hydrogen on the magnetic properties of YFe2A4.2 (A 5 on the magnetic properties of YFe2A4.2 compounds (A ¼ H, D) and probe the role of the cell volume difference, we

  8. Source and thermal maturity of bitumen in Precambrian Nonesuch Formation inferred from isotopic compositions of individual normal alkanes

    SciTech Connect (OSTI)

    Hieshima, G.B. (Indiana Univ., Bloomington (United States))

    1991-03-01T23:59:59.000Z

    As part of a continuing study of organic geochemistry of the 1.05 Ga Nonesuch Formation in the North American Mid-Continents rift, isotopic compositions of individual normal alkanes were measured using compound-specific isotopic analysis. This is a relatively new technique that can be used in conjunction with traditional biomarker analysis in interpretation of thermal maturity, oil-source rock correlation, and paleoecologic reconstruction. Carbon-isotopic compositions of individual normal alkanes from C{sub 15} to C{sub 25} in five bitumens and one oil from Nonesuch strata vary from {minus}28.8 to {minus}34.5{per thousand} (versus PDB). Within a given sample, isotopic compositions of n-alkanes span a range of 2 to 4 {per thousand}%. Homologues from C{sub 15} to C{sub 19} are isotopically light (depleted) by approximately 0.5{per thousand} relative to higher homologues from C{sub 20} to C{sub 25}. Two sources of normal alkanes are interpreted from the distribution of isotopic compositions. Based on chain length, the series from C{sub 15} to C{sub 19} may have been derived from algal components. Isotopically heavy, higher homologues are suspected to have been derived from bacterial sources. The pattern of isotopic compositions of bitumens is similar to that of the oil, demonstrating an oil-source rock relationship. Superimposed upon this primary, bimodal distribution of normal alkanes is the influence of thermal maturity on isotopic composition. Normal alkanes in samples of higher thermal maturity are enriched isotopically by 0.25 to 2{per thousand} relative to those of lower thermal maturity. Isotopic enrichment with increasing thermal maturity is interpreted to be the result of either addition of isotopically heavy components derived from kerogen and/or preferential loss through cracking of isotopically light components in bitumen.

  9. Global Security, Medical Isotopes, and Nuclear Science

    SciTech Connect (OSTI)

    Ahle, L E

    2007-09-17T23:59:59.000Z

    Over the past century basic nuclear science research has led to the use of radioactive isotopes into a wide variety of applications that touch our lives everyday. Some are obvious, such as isotopes for medical diagnostics and treatment. Others are less so, such as National/Global security issues. And some we take for granted, like the small amount of 241Am that is in every smoke detector. At the beginning of this century, we are in a position where the prevalence and importance of some applications of nuclear science are pushing the basic nuclear science community for improved models and nuclear data. Yet, at the same time, the push by the basic nuclear science community to study nuclei that are farther and farther away from stability also offer new opportunities for many applications. This talk will look at several global security applications of nuclear science, summarizing current R&D and need for improved nuclear data It will also look at how applications of nuclear science, such as to medicine, will benefit from the push for more and more powerful radioactive ion beam facilities.

  10. OXYGEN 18 EXCHANGE REACTIONS OF ALDEHYDES AND KETONES

    E-Print Network [OSTI]

    Byrn, Marianne; Calvin, Melvin

    1965-01-01T23:59:59.000Z

    OXYGEN 18 EXCHANGE REACTIONS OF ALDEHYDES AND KETONES TWO-eng-48 OXYGEN 18 EXCHANGE REACTIONS OF ALDEHYDES AND KETONES

  11. Oxygen Abundance Measurements of SHIELD Galaxies

    E-Print Network [OSTI]

    Haurberg, Nathalie C; Cannon, John M; Marshall, Melissa V

    2015-01-01T23:59:59.000Z

    We have derived oxygen abundances for 8 galaxies from the Survey of HI in Extremely Low-mass Dwarfs (SHIELD). The SHIELD survey is an ongoing study of very low-mass galaxies, with M$_{\\rm HI}$ between 10$^{6.5}$ and 10$^{7.5}$ M$_{\\odot}$, that were detected by the Arecibo Legacy Fast ALFA (ALFALFA) survey. H$\\alpha$ images from the WIYN 3.5m telescope show that these 8 SHIELD galaxies each possess one or two active star-forming regions which were targeted with long-slit spectral observations using the Mayall 4m telescope at KPNO. We obtained a direct measurement of the electron temperature by detection of the weak [O III] $\\lambda$4363 line in 2 of the HII regions. Oxygen abundances for the other HII regions were estimated using a strong-line method. When the SHIELD galaxies are plotted on a B-band luminosity-metallicity diagram they appear to suggest a slightly shallower slope to the relationship than normally seen. However, that offset is systematically reduced when the near-infrared luminosity is used ins...

  12. The effect of bed temperature on oxygen partial pressures in an atmospheric fluidized bed combustor

    SciTech Connect (OSTI)

    Malik, S.R. [PCSIR, Karachi (Pakistan). Fuel Research Centre; Gibbs, B.M. [Univ. of Leeds (United Kingdom). Dept. of Fuel and Energy

    1996-12-31T23:59:59.000Z

    One of the factors which cause corrosion of in-bed material is the existence of low oxygen levels. Therefore, oxygen`s partial pressure measurements are important for corrosion studies in atmospheric fluidized bed combustor (AFBC). The effect of bed temperature on oxygen levels has been discussed in this paper. The experiments were conducted on a 0.3 meters square combustor. In-bed oxygen partial pressures were measured using zirconia oxygen probes and recorded on a computerized data logging system. Detail statistical analysis of the data has been presented. The probability density function (PDF) was the most important statistical parameter which reveals not only how long environment is exposed to oxidizing reducing conditions but also the probability whether corrosion could occur.

  13. Diffusion in silicon isotope heterostructures

    SciTech Connect (OSTI)

    Silvestri, Hughes Howland

    2004-05-14T23:59:59.000Z

    The simultaneous diffusion of Si and the dopants B, P, and As has been studied by the use of a multilayer structure of isotopically enriched Si. This structure, consisting of 5 pairs of 120 nm thick natural Si and {sup 28}Si enriched layers, enables the observation of {sup 30}Si self-diffusion from the natural layers into the {sup 28}Si enriched layers, as well as dopant diffusion from an implanted source in an amorphous Si cap layer, via Secondary Ion Mass Spectrometry (SIMS). The dopant diffusion created regions of the multilayer structure that were extrinsic at the diffusion temperatures. In these regions, the Fermi level shift due to the extrinsic condition altered the concentration and charge state of the native defects involved in the diffusion process, which affected the dopant and self-diffusion. The simultaneously recorded diffusion profiles enabled the modeling of the coupled dopant and self-diffusion. From the modeling of the simultaneous diffusion, the dopant diffusion mechanisms, the native defect charge states, and the self- and dopant diffusion coefficients can be determined. This information is necessary to enhance the physical modeling of dopant diffusion in Si. It is of particular interest to the modeling of future electronic Si devices, where the nanometer-scale features have created the need for precise physical models of atomic diffusion in Si. The modeling of the experimental profiles of simultaneous diffusion of B and Si under p-type extrinsic conditions revealed that both species are mediated by neutral and singly, positively charged Si self-interstitials. The diffusion of As and Si under extrinsic n-type conditions yielded a model consisting of the interstitialcy and vacancy mechanisms of diffusion via singly negatively charged self-interstitials and neutral vacancies. The simultaneous diffusion of P and Si has been modeled on the basis of neutral and singly negatively charged self-interstitials and neutral and singly positively charged P species. Additionally, the temperature dependence of the diffusion coefficient of Si in Ge was measured over the temperature range of 550 C to 900 C using a buried Si layer in an epitaxially grown Ge layer.

  14. Analysis of hydrogen isotope mixtures

    DOE Patents [OSTI]

    Villa-Aleman, Eliel (Aiken, SC)

    1994-01-01T23:59:59.000Z

    An apparatus and method for determining the concentrations of hydrogen isotopes in a sample. Hydrogen in the sample is separated from other elements using a filter selectively permeable to hydrogen. Then the hydrogen is condensed onto a cold finger or cryopump. The cold finger is rotated as pulsed laser energy vaporizes a portion of the condensed hydrogen, forming a packet of molecular hydrogen. The desorbed hydrogen is ionized and admitted into a mass spectrometer for analysis.

  15. High-Precision Measurements of [superscript 33]S and [superscript 34]S Fractionation during SO[subscript 2] Oxidation Reveal Causes of Seasonality in SO[subscript 2] and Sulfate Isotopic Composition

    E-Print Network [OSTI]

    Harris, Eliza

    This study presents high-precision isotope ratio-mass spectrometric measurements of isotopic fractionation during oxidation of SO[subscript 2] by OH radicals in the gas phase and H[subscript 2]O[subscript 2] and transition ...

  16. Stable Isotope Dynamics in Cownose Rays (Rhinoptera bonasus) within the Northwestern Gulf of Mexico

    E-Print Network [OSTI]

    St. Clair, Katherine I

    2014-07-25T23:59:59.000Z

    investigation, there is limited information available on feeding patterns of cownose rays in the northwestern Gulf of Mexico. Stable isotope analysis has been used to study the foraging ecology of various species, but only recently applied to elasmobranchs...

  17. Floral succession and isotopic diagenesis of the Anahuac Formation at Damon Mound, Texas

    E-Print Network [OSTI]

    De Freest, Eric Scott

    1993-01-01T23:59:59.000Z

    , and L-5) have been studied for calcareous algal succession paleoecological interpretation and isotopic diagenesis. The Damon Mound reef complex is an ancient analog to present Gulf Coast bathymetric highs. The reef column represents a sequence...

  18. Stable nitrogen isotope measurements of marine bacterial proteins and nucleic acids: tracers of microbial activity

    E-Print Network [OSTI]

    Kovacs, Jeffrey Paul

    1996-01-01T23:59:59.000Z

    Stable nitrogen isotopes ([]15N) can trace elemental cycling in aquatic ecosystems if the enzyme mediated fractionations associated with nutrient uptake and assimilation are negligible or consistently predictable. In this study, bacterial proteins...

  19. A stable isotope stratigraphy for the Axel Heiberg Fossil Forest and its application to Eocene climate

    E-Print Network [OSTI]

    Byrne, Monica C. (Monica Catherine)

    2005-01-01T23:59:59.000Z

    The Eocene era was a warm, climatically dynamic transitional period between the Paleocene greenhouse world and the Oligocene icehouse world. This study details carbon and hydrogen isotopic and biomarker analyses of samples ...

  20. ISOTOPIC COMPOSITION OF LIGHT NUCLEI IN COSMIC RAYS: RESULTS FROM AMS-01

    E-Print Network [OSTI]

    Becker, R.

    The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper, we ...

  1. Developments in ITM oxygen technology for IGCC

    SciTech Connect (OSTI)

    Stein, V.E.E.; Richards, R.E.

    1999-07-01T23:59:59.000Z

    In partnership with the U.S. Department of Energy (DOE), an Air Products-led team (with Ceramatec, Eltron Research, McDermott Technology, NREC, Texaco, the Pennsylvania State University, and the University of Pennsylvania) is developing a new technology for air separation - Ion Transport Membrane Oxygen - based on the use of mixed-conducting ceramic membranes that have both electronic and oxygen ionic conductivity when operated at high temperature, typically 800 to 900 C. Under the influence of an oxygen partial-pressure driving force, the ITM Oxygen process achieves a high-purity, high-flux separation of oxygen from a compressed-air stream. By integrating the energy-rich, oxygen-depleted, non-permeate stream with a gas turbine system, the ITM Oxygen process becomes a co-producer of high-purity oxygen, power, and steam. Under a recent CRADA entitled ``Ion Transport Membranes (ITM) for Oxygen-Blown IGCC Systems and Indirect Coal Liquefaction,'' Air Products and DOE completed an initial quantification of the benefits of an ITM Oxygen-integrated IGCC facility. Compared to the cryogenic oxygen base case, the ITM Oxygen technology can potentially: reduce total installed costs by 7%; improve thermal efficiency for the integrated IGCC system by about 3%, leading to further decreases in carbon dioxide and sulfur emissions; and reduce the cost of generated electric power by more than 6%. The ITM Oxygen development project will proceed in three phases. Phase 1, which commenced under a DOE Cooperative Agreement in October 1998, is a 3-year effort focusing on construction of a technology development unit (TDU) for process concept validation tests at a capacity of 0.1 ton-per-day (TPD) oxygen. To accomplish this objective, the Air Products team will address relevant technical challenges in ITM Oxygen materials, engineering, membrane module development, and performance testing. During Phase 1 the team will also verify the economic prospects for integrating ITM Oxygen technology with IGCC and other advanced power generation systems. After at least one intermediate scaleup, Phase 2 and 3 activities will culminate with scaleup to a 25- to 50-TPD pre-commercial demonstration unit, fully integrated with a gas turbine. Meeting these challenges of developing cost-effective fabrication techniques for ITM Oxygen devices, and successfully integrating them with commercially available gas turbine engines, is key to bringing ITM Oxygen technology to the marketplace.

  2. Natural Ores as Oxygen Carriers in Chemical Looping Combustion

    SciTech Connect (OSTI)

    Tian, Hanjing; Siriwardane, Ranjani; Simonyi, Thomas; Poston, James

    2013-08-01T23:59:59.000Z

    Chemical looping combustion (CLC) is a combustion technology that utilizes oxygen from oxygen carriers (OC), such as metal oxides, instead of air to combust fuels. The use of natural minerals as oxygen carriers has advantages, such as lower cost and availability. Eight materials, based on copper or iron oxides, were selected for screening tests of CLC processes using coal and methane as fuels. Thermogravimetric experiments and bench-scale fixed-bed reactor tests were conducted to investigate the oxygen transfer capacity, reaction kinetics, and stability during cyclic reduction/oxidation reaction. Most natural minerals showed lower combustion capacity than pure CuO/Fe{sub 2}O{sub 3} due to low-concentrations of active oxide species in minerals. In coal CLC, chryscolla (Cu-based), magnetite, and limonite (Fe-based) demonstrated better reaction performances than other materials. The addition of steam improved the coal CLC performance when using natural ores because of the steam gasification of coal and the subsequent reaction of gaseous fuels with active oxide species in the natural ores. In methane CLC, chryscolla, hematite, and limonite demonstrated excellent reactivity and stability in 50-cycle thermogravimetric analysis tests. Fe{sub 2}O{sub 3}-based ores possess greater oxygen utilization but require an activation period before achieving full performance in methane CLC. Particle agglomeration issues associated with the application of natural ores in CLC processes were also studied by scanning electron microscopy (SEM).

  3. RADIOCHEMICAL STUDIES OF NEUTRON DEFICIENT ACTINIDE ISOTOPES

    E-Print Network [OSTI]

    Williams, Kimberly Eve

    2011-01-01T23:59:59.000Z

    Vandenbosch, J.R. Huizenga, Nuclear Fission, Academic Press,J.R. - Huizenga, Nuclear Fission, Academic Press, NY, p.fission barrier at the saddle "c c , - B point and T i s the nuclear

  4. RADIOCHEMICAL STUDIES OF NEUTRON DEFICIENT ACTINIDE ISOTOPES

    E-Print Network [OSTI]

    Williams, Kimberly Eve

    2011-01-01T23:59:59.000Z

    Nuclei" XI Winter Meeting on Nuclear Physics (January 1973).Nuclei" XI Winter Meeting on Nuclear Physics (January,

  5. Europium, Samarium, and Neodymium Isotopic Fractions in Metal-Poor Stars

    E-Print Network [OSTI]

    Ian U. Roederer; James E. Lawler; Christopher Sneden; John J. Cowan; Jennifer S. Sobeck; Catherine A. Pilachowski

    2007-12-16T23:59:59.000Z

    We have derived isotopic fractions of europium, samarium, and neodymium in two metal-poor giants with differing neutron-capture nucleosynthetic histories. These isotopic fractions were measured from new high resolution (R ~ 120,000), high signal-to-noise (S/N ~ 160-1000) spectra obtained with the 2dCoude spectrograph of McDonald Observatory's 2.7m Smith telescope. Synthetic spectra were generated using recent high-precision laboratory measurements of hyperfine and isotopic subcomponents of several transitions of these elements and matched quantitatively to the observed spectra. We interpret our isotopic fractions by the nucleosynthesis predictions of the stellar model, which reproduces s-process nucleosynthesis from the physical conditions expected in low-mass, thermally-pulsing stars on the AGB, and the classical method, which approximates s-process nucleosynthesis by a steady neutron flux impinging upon Fe-peak seed nuclei. Our Eu isotopic fraction in HD 175305 is consistent with an r-process origin by the classical method and is consistent with either an r- or an s-process origin by the stellar model. Our Sm isotopic fraction in HD 175305 suggests a predominantly r-process origin, and our Sm isotopic fraction in HD 196944 is consistent with an s-process origin. The Nd isotopic fractions, while consistent with either r-process or s-process origins, have very little ability to distinguish between any physical values for the isotopic fraction in either star. This study for the first time extends the n-capture origin of multiple rare earths in metal-poor stars from elemental abundances to the isotopic level, strengthening the r-process interpretation for HD 175305 and the s-process interpretation for HD196944.

  6. Development of high through-put Sr isotope analysis for monitoring reservoir integrity for CO{sub 2} storage.

    SciTech Connect (OSTI)

    Wall, Andy; Jain, Jinesh; Stewart, Brian; Capo, Rosemary; Hakala, Alexandra J.; Hammack, Richard; Guthrie, George

    2012-01-01T23:59:59.000Z

    Recent innovations in multi-collector ICP-mass spectrometry (MC-ICP-MS) have allowed for rapid and precise measurements of isotope ratios in geological samples. Naturally occurring Sr isotopes has the potential for use in Monitoring, Verification, and Accounting (MVA) associated with geologic CO2 storage. Sr isotopes can be useful for: Sensitive tracking of brine migration; Determining seal rock leakage; Studying fluid/rock reactions. We have optimized separation chemistry procedures that will allow operators to prepare samples for Sr isotope analysis off site using rapid, low cost methods.

  7. Stable Isotope Signatures for Microbial Forensics

    SciTech Connect (OSTI)

    Kreuzer, Helen W.

    2012-01-03T23:59:59.000Z

    The isotopic distribution of the atoms composing the molecules of microorganisms is a function of the substrates used by the organisms. The stable isotope content of an organism is fixed so long as no further substrate consumption and biosynthesis occurs, while the radioactive isotopic content decays over time. The distribution of stable isotopes of C, N, O and H in heterotrophic microorganisms is a direct function of the culture medium, and therefore the stable isotope composition can be used to associate samples with potential culture media and also with one another. The 14C content depends upon the 14C content, and therefore the age, of the organic components of the culture medium, as well as on the age of the culture itself. Stable isotope signatures can thus be used for sample matching, to associate cultures with specific growth media, and to predict characteristics of growth media.

  8. Stable Isotope Enrichment Capabilities at ORNL

    SciTech Connect (OSTI)

    Egle, Brian [ORNL; Aaron, W Scott [ORNL; Hart, Kevin J [ORNL

    2013-01-01T23:59:59.000Z

    The Oak Ridge National Laboratory (ORNL) and the US Department of Energy Nuclear Physics Program have built a high-resolution Electromagnetic Isotope Separator (EMIS) as a prototype for reestablishing a US based enrichment capability for stable isotopes. ORNL has over 60 years of experience providing enriched stable isotopes and related technical services to the international accelerator target community, as well as medical, research, industrial, national security, and other communities. ORNL is investigating the combined use of electromagnetic and gas centrifuge isotope separation technologies to provide research quantities (milligram to several kilograms) of enriched stable isotopes. In preparation for implementing a larger scale production facility, a 10 mA high-resolution EMIS prototype has been built and tested. Initial testing of the device has simultaneously collected greater than 98% enriched samples of all the molybdenum isotopes from natural abundance feedstock.

  9. Triple Oxygen Isotope Measurement of Nitrate to Analyze Impact of Aircraft Emissions

    E-Print Network [OSTI]

    Chan, Sharleen

    UEET characterized engine/ combustor emissions focusing onof alternative fuels and new combustor technology while

  10. An inverse approach to understanding benthic oxygen isotope records from the last deglaciation

    E-Print Network [OSTI]

    Amrhein, Daniel Edward

    2014-01-01T23:59:59.000Z

    Observations suggest that during the last deglaciation (roughly 20,000-10,000 years ago) the Earth warmed substantially, global sea level rose approximately 100 meters in response to melting ice sheets and glaciers, and ...

  11. Oxygen Kinetic Isotope Effects upon Catalytic Water Oxidation by a Monomeric Ruthenium Complex

    E-Print Network [OSTI]

    Roth, Justine P.

    Alfredo M. Angeles-Boza and Justine P. Roth* Department of Chemistry, Johns Hopkins University, 3400 North experimental data. INTRODUCTION Progress toward establishing a hydrogen economy1 requires a greater of oxidant have confirmed that 1 equiv of O2 is evolved every time 4 equiv of oxidant [ox] and base [B

  12. Competitive oxygen-18 kinetic isotope effects expose OO bond formation in water oxidation

    E-Print Network [OSTI]

    Roth, Justine P.

    in this area would be revolutionary, reducing toxic gas emissions6 and the devastation of natural environments7 relative to natural abundance H2O under single and multi-turnover conditions. The findings reported here while bolstering the global economy.8 A major objective in the basic energy sciences is to improve

  13. The effect of phosphomonoesterases on the oxygen isotope composition of phosphate

    E-Print Network [OSTI]

    Gilli, Adrian

    with acid phosphatases from wheat germ and potato tuber and alkaline phosphatase from Escherichia coli were phosphatases have been detected in marine systems (Perry, 1972; Hoppe, 2003), in freshwater lakes and rivers

  14. Isotopic dependence of predissociation linewidths in the Schumann-Runge bands of oxygen

    E-Print Network [OSTI]

    Cheung, A.S.-C.; Mok, D.K.-W.; Yoshino, K.; Parkinson, W.H.; Jamieson, M.J.

    Cheung,A.S.-C. Mok,D.K.-W. Yoshino,K. Parkinson,W.H. Jamieson,M.J. Dalgarno,A. Child,M.S. Journal of Chemical Physics, Vol. 103 pp 2369-2371

  15. Triple Oxygen Isotope Measurement of Nitrate to Analyze Impact of Aircraft Emissions

    E-Print Network [OSTI]

    Chan, Sharleen

    present trends of Fischer-Tropsch synthesis. Appl.Catal. ,at Figure 3: Overview of Fischer-Tropsch process. Carbonand undergoes the Fischer Tropsch process through catalysts

  16. consistent with the climate history from oxygen isotopes and the general notion that

    E-Print Network [OSTI]

    Hedges, Blair

    , R. A. Am. J. Sci. 294, 56­91 (1994). 3. Frakes, L. A., Francis, J. E. & Syktus, J. I. Climate Modes

  17. Triple Oxygen Isotope Measurement of Nitrate to Analyze Impact of Aircraft Emissions

    E-Print Network [OSTI]

    Chan, Sharleen

    feedstock is processed into Syngas (mixture of CO and H2)called synthetic gas or syngas) reacts with catalysts (feedstock is processed into Syngas (mixture of CO and H2)

  18. Oxygen Isotope Evidence For Past And Present Hydrothermal Regimes Of Long

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation, searchOfRoseConcernsCompany OilInformationPre-TaxShelfOxfordValley Caldera,

  19. Properties of Reactive Oxygen Species by Quantum Monte Carlo

    E-Print Network [OSTI]

    Andrea Zen; Bernhardt L. Trout; Leonardo Guidoni

    2014-06-16T23:59:59.000Z

    The electronic properties of the oxygen molecule, in its singlet and triplet states, and of many small oxygen-containing radicals and anions have important roles in different fields of Chemistry, Biology and Atmospheric Science. Nevertheless, the electronic structure of such species is a challenge for ab-initio computational approaches because of the difficulties to correctly describe the statical and dynamical correlation effects in presence of one or more unpaired electrons. Only the highest-level quantum chemical approaches can yield reliable characterizations of their molecular properties, such as binding energies, equilibrium structures, molecular vibrations, charge distribution and polarizabilities. In this work we use the variational Monte Carlo (VMC) and the lattice regularized Monte Carlo (LRDMC) methods to investigate the equilibrium geometries and molecular properties of oxygen and oxygen reactive species. Quantum Monte Carlo methods are used in combination with the Jastrow Antisymmetrized Geminal Power (JAGP) wave function ansatz, which has been recently shown to effectively describe the statical and dynamical correlation of different molecular systems. In particular we have studied the oxygen molecule, the superoxide anion, the nitric oxide radical and anion, the hydroxyl and hydroperoxyl radicals and their corresponding anions, and the hydrotrioxyl radical. Overall, the methodology was able to correctly describe the geometrical and electronic properties of these systems, through compact but fully-optimised basis sets and with a computational cost which scales as $N^3-N^4$, where $N$ is the number of electrons. This work is therefore opening the way to the accurate study of the energetics and of the reactivity of large and complex oxygen species by first principles.

  20. Stable Isotope Protocols: Sampling and Sample Processing

    E-Print Network [OSTI]

    Levin, Lisa A; Currin, Carolyn

    2012-01-01T23:59:59.000Z

    plants, benthic microalgae [BMI], benthic macroalgae) andin a dessicator, prior to analysis. A.2 Benthic microalgaeBenthic microalgae (BMI) can be collected for isotope

  1. EIS-0249: Medical Isotopes Production Project

    Broader source: Energy.gov [DOE]

    This EIS evaluates the potential environmental impacts of a proposal to establish a production capability for molybdenum-99 (Mo-99) and related medical isotopes.

  2. Integration of Nontraditional Isotopic Systems Into Reaction...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Water-Rock Interaction, and Impacts of Water Chemistry on Reservoir Sustainability Integration of Nontraditional Isotopic Systems Into Reaction-Transport Models of EGS For...

  3. Atom trap trace analysis of krypton isotopes

    SciTech Connect (OSTI)

    Bailey, K.; Chen, C. Y.; Du, X.; Li, Y. M.; Lu, Z.-T.; O'Connor, T. P.; Young, L.

    1999-11-17T23:59:59.000Z

    A new method of ultrasensitive isotope trace analysis has been developed. This method, based on the technique of laser manipulation of neutral atoms, has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton gas sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. This method is free of contamination from other isotopes and elements and can be applied to several different isotope tracers for a wide range of applications. The demonstrated detection efficiency is 1 x 10{sup {minus}7}. System improvements could increase the efficiency by many orders of magnitude.

  4. Method for isotope enrichment by photoinduced chemiionization

    DOE Patents [OSTI]

    Dubrin, James W. (Walnut Creek, CA)

    1985-01-01T23:59:59.000Z

    Isotope enrichment, particularly .sup.235 U enrichment, is achieved by irradiating an isotopically mixed vapor feed with radiant energy at a wavelength or wavelengths chosen to selectively excite the species containing a desired isotope to a predetermined energy level. The vapor feed if simultaneously reacted with an atomic or molecular reactant species capable of preferentially transforming the excited species into an ionic product by a chemiionization reaction. The ionic product, enriched in the desired isotope, is electrostatically or electromagnetically extracted from the reaction system.

  5. O isotopic composition of CaCO3 measured by continuous ow isotope ratio mass spectrometry

    E-Print Network [OSTI]

    d13 C and d18 O isotopic composition of CaCO3 measured by continuous ¯ow isotope ratio mass. This new method streamlines the classical phosphoric acid/calcium carbonate (H3PO4/CaCO3) reaction method XL continuous flow isotope ratio mass spectrometer. Conditions for which the H3PO4/CaCO3 reaction

  6. Electrochemical oxygen pumps. Final CRADA report.

    SciTech Connect (OSTI)

    Carter, J. D.

    2009-10-01T23:59:59.000Z

    All tasks of the Work Plan of ISTC Project 2277p have been completed, thus: (1) techniques of chemical synthesis were developed for more than ten recipes of electrolyte based on cerium oxide doped with 20 mole% of gadolinium (CeGd)O{sub 2}, doped by more than 10 oxide systems including 6 recipes in addition to the Work Plan; (2) electric conductivity and mechanical strength of CeGd specimens with additions of oxide systems were performed, two candidate materials for the electrolyte of electrochemical oxygen pump (pure CeGd and CeGd doped by 0.2 wt% of a transition metal) were chosen; (3) extended studies of mechanical strength of candidate material specimens were performed at room temperature and at 400, 600, 800 C; (4) fixtures for determination of mechanical strength of tubes by external pressure above 40 atmospheres at temperature up to 700 C were developed and fabricated; and (5) technology of slip casting of tubes from pure (Ce,Gd)O{sub 2} and of (Ce,Gd)O{sub 2} doped by 0.2 wt% of a transition metal, withstanding external pressure of minimum 40 atmospheres at temperature up to 700 C was developed, a batch of tubes was sent for testing to Argonne National Laboratory; (6) technology of making nanopowder from pure (Ce,Gd)O{sub 2} was developed based on chemical synthesis and laser ablation techniques, a batch of nanopowder with the weight 1 kg was sent for testing to Argonne National Laboratory; (7) a business plan for establishing a company for making powders of materials for electrochemical oxygen pump was developed; and (8) major results obtained within the Project were reported at international conferences and published in the Russian journal Electrochemistry. In accordance with the Work Plan a business trip of the following project participants was scheduled for April 22-29, 2006, to Tonawanda, NY, USA: Manager Victor Borisov; Leader of technology development Gennady Studenikin; Leader of business planning Elena Zadorozhnaya; Leader of production Vasily Lepalovsky; and Translator Vladimir Litvinov. During this trip project participants were to discuss with the project Technical Monitor J.D. Carter and representative of Praxair Inc. J. Chen the results of project activities (prospects of transition metal-doped material application in oxygen pumps), as well as the prospects of cooperation with Praxair at the meeting with the company management in the following fields: (1) Deposition of thin films of oxide materials of complex composition on support by magnetron and ion sputtering, research of coatings properties; (2) Development of block-type structure technology (made of porous and dense ceramics) for oxygen pump. The block-type structure is promising because when the size of electrolyte block is 2 x 2 inches and assembly height is 10 inches (5 blocks connected together) the area of active surface is ca. 290 square inches (in case of 8 slots), that roughly corresponds to one tube with diameter 1 inch and height 100 inches. So performance of the system made of such blocks may be by a factor of two or three higher than that of tube-based system. However one month before the visit, J. Chen notified us of internal changes at Praxair and the cancellation of the visit to Tonawanda, NY. During consultations with the project Technical Monitor J.D. Carter and Senior Project Manager A. Taylor a decision was made to extend the project term by 2 quarters to prepare proposals for follow-on activities during this extension (development of block-type structures made of dense and porous oxide ceramics for electrochemical oxygen pumps) using the funds that were not used for the trip to the US.

  7. Ab Initio Nuclear Structure and Reaction Calculations for Rare Isotopes

    SciTech Connect (OSTI)

    Draayer, Jerry P [Louisiana State University

    2014-09-28T23:59:59.000Z

    We have developed a novel ab initio symmetry-adapted no-core shell model (SA-NCSM), which has opened the intermediate-mass region for ab initio investigations, thereby providing an opportunity for first-principle symmetry-guided applications to nuclear structure and reactions for nuclear isotopes from the lightest p-shell systems to intermediate-mass nuclei. This includes short-lived proton-rich nuclei on the path of X-ray burst nucleosynthesis and rare neutron-rich isotopes to be produced by the Facility for Rare Isotope Beams (FRIB). We have provided ab initio descriptions of high accuracy for low-lying (including collectivity-driven) states of isotopes of Li, He, Be, C, O, Ne, Mg, Al, and Si, and studied related strong- and weak-interaction driven reactions that are important, in astrophysics, for further understanding stellar evolution, X-ray bursts and triggering of s, p, and rp processes, and in applied physics, for electron and neutrino-nucleus scattering experiments as well as for fusion ignition at the National Ignition Facility (NIF).

  8. Enhanced collectivity in neutron-deficient Sn isotopes in energy functional based collective Hamiltonian

    E-Print Network [OSTI]

    Z. P. Li; C. Y. Li; J. Xiang; J. M. Yao; J. Meng

    2012-09-26T23:59:59.000Z

    The low-lying collective states in Sn isotopes are studied by a five-dimensional collective Hamiltonian with parameters determined from the triaxial relativistic mean-field calculations using the PC-PK1 energy density functional. The systematics for both the excitation energies of $2^+_1$ states and $B(E2;0^+_1\\to 2^+_1)$ values are reproduced rather well, in particular, the enhanced E2 transitions in the neutron-deficient Sn isotopes with Ncollectivity in the isotopes around N=58.

  9. Age and isotopic relationships among the angrites Lewis Cliff 86010 and Angra dos Reis

    SciTech Connect (OSTI)

    Lugmair, G.W. (Univ. of California, San Diego, La Jolla (United States)); Galer, S.J.G. (Univ. of California, San Diego, La Jolla (United States) Max-Planck-Inst. fuer Chemie, Mainz (West Germany))

    1992-04-01T23:59:59.000Z

    Results of a wide-ranging isotopic investigation of the unique Antarctican angrite LEW-86010 (LEW) are presented, together with a reassessment of the type angrite Angra dos Reis (ADOR). The principal objectives of this study are to obtain precise radiometric ages, initial Sr isotopic compositions, and to search for the erstwhile presence of the short-lived nuclei {sup 146}Sm and {sup 26}Al via their daughter products. The isotopic compositions of Sm, U, Ca, and Ti were also measured. This allows a detailed appraisal to be made of the relations between, and the genealogy of, these two angrites.

  10. Existence of long-lived isotopes of a superheavy element in natural Au

    E-Print Network [OSTI]

    A. Marinov; I. Rodushkin; A. Pape; Y. Kashiv; D. Kolb; R. Brandt; R. V. Gentry; H. W. Miller; L. Halicz; I. Segal

    2007-02-25T23:59:59.000Z

    Evidence for the existence of long-lived isotopes with atomic mass numbers 261 and 265 and abundance of (1-10)x10$^{-10}$ relative to Au has been found in a study of natural Au using an inductively coupled plasma - sector field mass spectrometer. The measured masses fit the predictions made for the masses of $^{261}$Rg and $^{265}$Rg (Z=111) and for some isotopes of nearby elements. The possibility that these isotopes belong to the recently discovered class of long-lived high spin super- and hyperdeformed isomeric states is discussed.

  11. Positive parity states and some electromagnetic transition properties of even-odd europium isotopes

    SciTech Connect (OSTI)

    Yazar, Harun Resit, E-mail: yazar@nevsehir.edu.tr [Nevsehir University, Faculty of Art and Science (Turkey)

    2013-06-15T23:59:59.000Z

    The positive-parity low-spin states of even-odd Europium isotopes ({sup 151-155}Eu) were studied within the framework of the interacting boson-fermion model. The calculated positive low-spin state energy spectra of the odd Eu isotope were found to agree quite well with the experimental data. The B(E2) values were also calculated and it was found that the calculated positive-parity low-spin state energy spectra of the odd-A Eu isotopes agree quite well with the experimental data.

  12. Discovery of Isotopes of Elements with Z $\\ge$ 100

    E-Print Network [OSTI]

    M. Thoennessen

    2012-03-09T23:59:59.000Z

    Currently, 163 isotopes of elements with Z $\\ge$ 100 have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  13. Gamma Spectrum from Neutron Capture on Tungsten Isotopes

    E-Print Network [OSTI]

    Hurst, Aaron

    2011-01-01T23:59:59.000Z

    FROM NEUTRON CAPTURE ON TUNGSTEN ISOTOPES A. M. HURST ?1,2 ,capture on the stable tungsten isotopes is presented, withknown decay schemes of the tungsten isotopes from neutron

  14. Myocardial Reloading after Extracorporeal Membrane Oxygenation...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Protein Synthesis. Abstract: Extracorporeal membrane oxygenation (ECMO) unloads the heart providing a bridge to recovery in children after myocardial stunning. Mortality after...

  15. The Role of Oxygen in Coal Gasification

    E-Print Network [OSTI]

    Klosek, J.; Smith, A. R.; Solomon, J.

    in downst eam absorbs oxygen from air at low pressure by units. Selection of the optimum oxygen urHy contact with a circulating molten salt. High must be performed by optimizing the capit land purity (>99.5%) oxygen is regenerated from the operating... are evaluated, the use of oxygen is often preferred over air regardless of the pressure requirement. GOX GAN WASTE AIR FROM MOL SIEVE MAIN EXCHANGERS EXPANDER Figure 4 - Low Pressure Cryogenic Cycle Below about 95% purity, the specific power (k...

  16. THE GENESIS SOLAR WIND CONCENTRATOR TARGET: MASS FRACTIONATION CHARACTERISED BY NE ISOTOPES

    SciTech Connect (OSTI)

    WIENS, ROGER C. [Los Alamos National Laboratory; OLINGER, C. [Los Alamos National Laboratory; HEBER, V.S. [Los Alamos National Laboratory; REISENFELD, D.B. [Los Alamos National Laboratory; BURNETT, D.S. [Los Alamos National Laboratory; ALLTON, J.H. [Los Alamos National Laboratory; BAUR, H. [Los Alamos National Laboratory; WIECHERT, U. [Los Alamos National Laboratory; WIELER, R. [Los Alamos National Laboratory

    2007-01-02T23:59:59.000Z

    The concentrator on Genesis provides samples of increased fluences of solar wind ions for precise determination of the oxygen isotopic composition of the solar wind. The concentration process caused mass fractionation as function of the radial target position. They measured the fractionation using Ne released by UV laser ablation along two arms of the gold cross from the concentrator target to compare measured Ne with modeled Ne. The latter is based on simulations using actual conditions of the solar wind during Genesis operation. Measured Ne abundances and isotopic composition of both arms agree within uncertainties indicating a radial symmetric concentration process. Ne data reveal a maximum concentration factor of {approx} 30% at the target center and a target-wide fractionation of Ne isotopes of 3.8%/amu with monotonously decreasing {sup 20}Ne/{sup 22}Ne ratios towards the center. The experimentally determined data, in particular the isotopic fractionation, differ from the modeled data. They discuss potential reasons and propose future attempts to overcome these disagreements.

  17. Shell model description of Ge isotopes

    E-Print Network [OSTI]

    J. G. Hirsch; P. C. Srivastava

    2012-04-12T23:59:59.000Z

    A shell model study of the low energy region of the spectra in Ge isotopes for $38\\leq N\\leq 50$ is presented, analyzing the excitation energies, quadrupole moments, $B(E2)$ values and occupation numbers. The theoretical results have been compared with the available experimental data. The shell model calculations have been performed employing three different effective interactions and valence spaces.We have used two effective shell model interactions, JUN45 and jj44b, for the valence space $f_{5/2} \\, p \\,g_{9/2}$ without truncation. To include the proton subshell $f_{7/2}$ in valence space we have employed the $fpg$ effective interaction due to Sorlin {\\it et al.}, with $^{48}$Ca as a core and a truncation in the number of excited particles.

  18. Photonuclear Reaction Cross Sections for Gallium Isotopes

    E-Print Network [OSTI]

    Serkan Akkoyun; Tuncay Bayram

    2014-09-08T23:59:59.000Z

    The photon induced reactions which are named as photonuclear reactions have a great importance in many field of nuclear, radiation physics and related fields. Since we have planned to perform photonuclear reaction on gallium target with bremmstrahlung photons from clinical linear accelerator in the future, the cross-sections of neutron (photo-neutron ({\\gamma},xn)) and proton (photo-proton ({\\gamma},xn)) productions after photon activation have been calculated by using TALYS 1.2 computer code in this study. The target nucleus has been considered gallium which has two stable isotopes, 69Ga and 71Ga. According to the results, we have seen that the calculations are in harmony in the limited literature values. Furthermore, the pre-equilibrium and compound process contributions to the total cross-section have been investigated.

  19. Oxygen ion-beam microlithography

    DOE Patents [OSTI]

    Tsuo, Y. Simon (Lakewood, CO)

    1991-01-01T23:59:59.000Z

    A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used.

  20. Oxygen ion-beam microlithography

    DOE Patents [OSTI]

    Tsuo, Y.S.

    1991-08-20T23:59:59.000Z

    A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used. 5 figures.

  1. Geothermal waters from the Taupo Volcanic Zone, New Zealand: Li,1 B and Sr isotopes characterization2

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Geothermal waters from the Taupo Volcanic Zone, New Zealand: Li,1 B and Sr isotopes 13 In this study, we report chemical and isotope data for 23 geothermal water samples collected geothermal waters collected from deep boreholes16 in different geothermal fields (Ohaaki, Wairakei, Mokai

  2. Transient oxygen consumption rate measurements with the BDT?M? oxygen biosensor system

    E-Print Network [OSTI]

    Low, Clarke Alan

    2008-01-01T23:59:59.000Z

    Oxygen consumption rate (OCR) is a reliable indicator of tissue health. Recently, the OCR of isolated human islets has been shown to predict transplant outcome in diabetic mice. The Oxygen Biosensor System (OBS) is a ...

  3. Tropical Pacific nutrient dynamics in the modern and pleistocene ocean : insights from the nitrogen isotope system

    E-Print Network [OSTI]

    Rafter, Patrick Anthony

    2009-01-01T23:59:59.000Z

    nitrogen isotopes, an enrichment that is conventionallyisotopes upon denitrification also imparts a strong isotopic enrichment

  4. Isotopic Scaling in Nuclear Reactions

    E-Print Network [OSTI]

    M. B. Tsang; W. A. Friedman; C. K. Gelbke; W. G. Lynch; G. Verde; H. Xu

    2001-03-26T23:59:59.000Z

    A three parameter scaling relationship between isotopic distributions for elements with Z$\\leq 8$ has been observed that allows a simple description of the dependence of such distributions on the overall isospin of the system. This scaling law (termed iso-scaling) applies for a variety of reaction mechanisms that are dominated by phase space, including evaporation, multifragmentation and deeply inelastic scattering. The origins of this scaling behavior for the various reaction mechanisms are explained. For multifragmentation processes, the systematics is influenced by the density dependence of the asymmetry term of the equation of state.

  5. Stable carbon and nitrogen isotope enrichment in primate tissues

    E-Print Network [OSTI]

    Crowley, Brooke E.; Carter, Melinda L.; Karpanty, Sarah M.; Zihlman, Adrienne L.; Koch, Paul L.; Dominy, Nathaniel J.

    2010-01-01T23:59:59.000Z

    carbon and nitrogen isotope enrichment in primate tissuesfactor (a) and isotope enrichment values (e), which provideisotope values from different modern primate tissues. Additionally, using these mean apparent enrichment

  6. CRAD, Engineering - Oak Ridge National Laboratory High Flux Isotope...

    Broader source: Energy.gov (indexed) [DOE]

    Engineering - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR CRAD, Engineering - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR...

  7. CRAD, Engineering - Oak Ridge National Laboratory High Flux Isotope...

    Broader source: Energy.gov (indexed) [DOE]

    Oak Ridge National Laboratory High Flux Isotope Reactor CRAD, Engineering - Oak Ridge National Laboratory High Flux Isotope Reactor February 2007 A section of Appendix C to DOE G...

  8. aluminium isotopes: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: Currently, 31 actinium, 31 thorium, 28 protactinium, and 23 uranium isotopes have so far been observed; the discovery of these isotopes is discussed. For...

  9. americium isotopes: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: Currently, 31 actinium, 31 thorium, 28 protactinium, and 23 uranium isotopes have so far been observed; the discovery of these isotopes is discussed. For...

  10. activated bismuth isotopes: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: Currently, 31 actinium, 31 thorium, 28 protactinium, and 23 uranium isotopes have so far been observed; the discovery of these isotopes is discussed. For...

  11. astatine isotopes: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CERN Preprints Summary: Currently, 31 actinium, 31 thorium, 28 protactinium, and 23 uranium isotopes have so far been observed; the discovery of these isotopes is discussed. For...

  12. A Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal...

    Open Energy Info (EERE)

    Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal System Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Helium Isotope...

  13. Isotopic Analysis- Fluid At Dixie Valley Geothermal Area (Kennedy...

    Open Energy Info (EERE)

    geothermal resources with deep, fault hosted permeable fluid flow pathways and the helium Isotopic composition of the surface fluids. The authors suggest that helium isotopes...

  14. applied isotope techniques: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    M. 22 Applied Radiation and Isotopes 55 (2001) 707713 Bronchial dosimeter for radon progeny Biology and Medicine Websites Summary: Applied Radiation and Isotopes 55 (2001)...

  15. High density adsorbed oxygen on Rh,,111... and enhanced routes to metallic oxidation using atomic oxygen

    E-Print Network [OSTI]

    Sibener, Steven

    High density adsorbed oxygen on Rh,,111... and enhanced routes to metallic oxidation using atomic oxygen K. D. Gibson, Mark Viste, Errol C. Sanchez, and S. J. Sibener The James Franck Institute; accepted 30 November 1998 Exposure of Rh 111 to atomic oxygen leads to the facile formation of a full

  16. Advanced Mass Spectrometers for Hydrogen Isotope Analyses

    SciTech Connect (OSTI)

    Chastagner, P.

    2001-08-01T23:59:59.000Z

    This report is a summary of the results of a joint Savannah River Laboratory (SRL) - Savannah River Plant (SRP) ''Hydrogen Isotope Mass Spectrometer Evaluation Program''. The program was undertaken to evaluate two prototype hydrogen isotope mass spectrometers and obtain sufficient data to permit SRP personnel to specify the mass spectrometers to replace obsolete instruments.

  17. Positive and inverse isotope effect on superconductivity

    E-Print Network [OSTI]

    Tian De Cao

    2009-09-04T23:59:59.000Z

    This article improves the BCS theory to include the inverse isotope effect on superconductivity. An affective model can be deduced from the model including electron-phonon interactions, and the phonon-induced attraction is simply and clearly explained on the electron Green function. The focus of this work is on how the positive or inverse isotope effect occurs in superconductors.

  18. MARK E. CONRAD Center for Isotope Geochemistry

    E-Print Network [OSTI]

    Ajo-Franklin, Jonathan

    with stable isotopes, fate and transport of groundwater contaminants, vadose zone hydrology, metal uptake by lichens, paleoclimatic patterns in California and stable isotope systematics of clay minerals. Geologist of gold property in the Mother Lode of California. Exploration Geologist (Anaconda Minerals Company; 6

  19. [Carbon isotope fractionation inplants]. Final report

    SciTech Connect (OSTI)

    O`Leary, M.H.

    1990-12-31T23:59:59.000Z

    The objectives of this research are: To develop a theoretical and experimental framework for understanding isotope fractionations in plants; and to develop methods for using this isotope fractionation for understanding the dynamics of CO{sub 2} fixation in plants. Progress is described.

  20. Oxygen and Nitrogen Contamination During Arc Welding

    E-Print Network [OSTI]

    Eagar, Thomas W.

    ) ) : ,- Oxygen and Nitrogen Contamination During Arc Welding T. W. Eagar Department of }faterials, shielded metal arc, self-shielded metal arc, and submerged arc welding are reviewed. Calcu- lations upon heating is also discussed. Introduction Oxygen and nitrogen ~ontamination of weld metal

  1. New Oxygen-Production Technology Proving Successful

    Broader source: Energy.gov [DOE]

    The Office of Fossil Energy's National Energy Technology Laboratory has partnered with Air Products and Chemicals Inc. of Allentown, Penn. to develop the Ion Transport Membrane (ITM) Oxygen, a revolutionary new oxygen-production technology that requires less energy and offers lower capital costs than conventional technologies.

  2. Inferences from the vertical distribution of Fe isotopic compositions1 on pedogenetic processes in soils2

    E-Print Network [OSTI]

    Boyer, Edmond

    studied using Fe isotopes and classical soil parameters.4 In the Cambisol, Fe transfer is limited; in-situ in soils2 Z. Fekiacova1 , S. Pichat2 , S. Cornu1 and J. Balesdent1 3 4 5 1 INRA - UR1119 Géochimie des sols.geoderma.2013.06.007 #12;2 ABSTRACT1 The isotopic compositions of major elements in soils can help understand

  3. An informatics based analysis of the impact of isotope substitution on phonon modes in graphene

    SciTech Connect (OSTI)

    Broderick, Scott; Srinivasan, Srikant; Rajan, Krishna [Department of Material Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States); Ray, Upamanyu; Balasubramanian, Ganesh, E-mail: bganesh@iastate.edu [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2014-06-16T23:59:59.000Z

    It is shown by informatics that the high frequency short ranged modes exert a significant influence in impeding thermal transport through isotope substituted graphene nanoribbons. Using eigenvalue decomposition methods, we have extracted features in the phonon density of states spectra that reveal correlations between isotope substitution and phonon modes. This study also provides a data driven computational framework for the linking of materials chemistry and transport properties in 2D systems.

  4. Nucleon density in the nuclear periphery determined with antiprotonic x-rays cadmium and tin isotopes

    E-Print Network [OSTI]

    Schmidt, R; Czosnyka, T; Von Egidy, T; Gulda, K; Hartmann, F J; Jastrzebski, J J; Ketzer, B; Kisielinski, M; Klos, B; Kurcewicz, W; Lubinski, P; Napiorkowski, P J; Pienkowski, L; Smolanczuk, R; Widmann, E; Wycech, S

    2003-01-01T23:59:59.000Z

    The x-ray cascade from antiprotonic atoms was studied for 106Cd, 116Cd, 112Sn, 116Sn, 120Sn, and 124Sn. Widths and shifts of the levels due to strong interaction were deduced. Isotopic effects in the Cd and Sn isotopes are clearly seen. The results are used to investigate the nucleon density in the nuclear periphery. The deduced neutron distributions are compared with the results of the previously introduced radiochemical method and with HFB calculations.

  5. The effect of plutonium dioxide water surface coverage on the generation of hydrogen and oxygen

    SciTech Connect (OSTI)

    Veirs, Douglas K. [Los Alamos National Laboratory; Berg, John M. [Los Alamos National Laboratory; Crowder, Mark L. [Savannah River National Laboratory

    2012-06-20T23:59:59.000Z

    The conditions for the production of oxygen during radiolysis of water adsorbed onto plutonium dioxide powder are discussed. Studies in the literature investigating the radiolysis of water show that both oxygen and hydrogen can be generated from water adsorbed on high-purity plutonium dioxide powder. These studies indicate that there is a threshold in the amount of water below which oxygen is not generated. The threshold is associated with the number of monolayers of adsorbed water and is shown to occur at approximately two monolayers of molecularly adsorbed water. Material in equilibrium with 50% relative humidity (RH) will be at the threshold for oxygen generation. Using two monolayers of molecularly adsorbed water as the threshold for oxygen production, the total pressure under various conditions is calculated assuming stoichiometric production of hydrogen and oxygen. The specific surface area of the oxide has a strong effect on the final partial pressure. The specific surface areas resulting in the highest pressures within a 3013 container are evaluated. The potential for oxygen generation is mitigated by reduced relative humidity, and hence moisture adsorption, at the oxide surface which occurs if the oxide is warmer than the ambient air. The potential for oxygen generation approaches zero as the temperature difference between the ambient air and the material approaches 6 C.

  6. OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

    SciTech Connect (OSTI)

    David R. Thompson; Lawrence E. Bool; Jack C. Chen

    2001-04-01T23:59:59.000Z

    This quarterly technical progress report will summarize work accomplished for the Program through the fourth quarter January-March 2001 in the following task areas: Task 1 - Oxygen Enhanced Combustion, Task 2 - Oxygen Transport Membranes and Task 4 - Program Management. This report will also recap the results of the past year. The program is proceeding in accordance with the objectives for the first year. OTM material characterization was completed. 100% of commercial target flux was demonstrated with OTM disks. The design and assembly of Praxair's single tube high-pressure test facility was completed. The production of oxygen with a purity of better than 99.5% was demonstrated. Coal combustion testing was conducted at the University of Arizona. Modest oxygen enhancement resulted in NOx emissions reduction. The injector for oxygen enhanced coal based reburning was conducted at Praxair. Combustion modeling with Keystone boiler was completed. Pilot-scale combustion test furnace simulations continued this quarter.

  7. Descriptions of carbon isotopes within the energy density functional theory

    SciTech Connect (OSTI)

    Ismail, Atef [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia and Department of Physics, Al-Azhar University, 71524 Assiut (Egypt); Cheong, Lee Yen; Yahya, Noorhana [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Tammam, M. [Department of Physics, Al-Azhar University, 71524 Assiut (Egypt)

    2014-10-24T23:59:59.000Z

    Within the energy density functional (EDF) theory, the structure properties of Carbon isotopes are systematically studied. The shell model calculations are done for both even-A and odd-A nuclei, to study the structure of rich-neutron Carbon isotopes. The EDF theory indicates the single-neutron halo structures in {sup 15}C, {sup 17}C and {sup 19}C, and the two-neutron halo structures in {sup 16}C and {sup 22}C nuclei. It is also found that close to the neutron drip-line, there exist amazing increase in the neutron radii and decrease on the binding energies BE, which are tightly related with the blocking effect and correspondingly the blocking effect plays a significant role in the shell model configurations.

  8. ISOTOPES

    E-Print Network [OSTI]

    Lederer, C. Michael

    2013-01-01T23:59:59.000Z

    constructed to enrich liquid UF6 slightly as feed for thej) b. Optimum a. s: .X. UF6 feed, (kg per year) XBL 7912 -

  9. ISOTOPES

    E-Print Network [OSTI]

    Lederer, C. Michael

    2013-01-01T23:59:59.000Z

    lithium hydroxide (56, 14), A plant utilizing this reaction to produce 1000 kg per year of 99.99% 7Li at a price

  10. ISOTOPES

    E-Print Network [OSTI]

    Lederer, C. Michael

    2013-01-01T23:59:59.000Z

    §fissile materials in fast breeder reactors currently underwater reactor, FBR = fast breeder reactor. The band belowinc 1 udes heavy-water reactors, fast breeders, and 11

  11. ISOTOPES

    E-Print Network [OSTI]

    Lederer, C. Michael

    2013-01-01T23:59:59.000Z

    1978). United States Gas Centrifuge Program for 72. Energy~~;h)radius in a gas centrifuge with va 400 m/s. P 0 and U68,14) of a gas centrifuge with radius = 0.09145 m, length=

  12. ISOTOPES

    E-Print Network [OSTI]

    Lederer, C. Michael

    2013-01-01T23:59:59.000Z

    the columns used to separate UF5, which had a separativeof uranium by dissociation of UF5, by multiple vibrational

  13. Atomic vapor laser isotope separation of lead-210 isotope

    DOE Patents [OSTI]

    Scheibner, K.F.; Haynam, C.A.; Johnson, M.A.; Worden, E.F.

    1999-08-31T23:59:59.000Z

    An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207. 5 figs.

  14. Atomic vapor laser isotope separation of lead-210 isotope

    DOE Patents [OSTI]

    Scheibner, Karl F. (Tracy, CA); Haynam, Christopher A. (Pleasanton, CA); Johnson, Michael A. (Pleasanton, CA); Worden, Earl F. (Diablo, CA)

    1999-01-01T23:59:59.000Z

    An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207.

  15. OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

    SciTech Connect (OSTI)

    David R. Thompson; Lawrence E. Bool; Jack C. Chen

    2004-04-01T23:59:59.000Z

    Conventional wisdom says adding oxygen to a combustion system enhances product throughput, system efficiency, and, unless special care is taken, increases NOx emissions. This increase in NOx emissions is typically due to elevated flame temperatures associated with oxygen use leading to added thermal NOx formation. Innovative low flame temperature oxy-fuel burner designs have been developed and commercialized to minimize both thermal and fuel NOx formation for gas and oil fired industrial furnaces. To be effective these systems require close to 100% oxy-fuel combustion and the cost of oxygen is paid for by fuel savings and other benefits. For applications to coal-fired utility boilers at the current cost of oxygen, however, it is not economically feasible to use 100% oxygen for NOx control. In spite of this conventional wisdom, Praxair and its team members, in partnership with the US Department of Energy National Energy Technology Laboratory, have developed a novel way to use oxygen to reduce NOx emissions without resorting to complete oxy-fuel conversion. In this concept oxygen is added to the combustion process to enhance operation of a low NOx combustion system. Only a small fraction of combustion air is replaced with oxygen in the process. By selectively adding oxygen to a low NOx combustion system it is possible to reduce NOx emissions from nitrogen-containing fuels, including pulverized coal, while improving combustion characteristics such as unburned carbon. A combination of experimental work and modeling was used to define how well oxygen enhanced combustion could reduce NOx emissions. The results of this work suggest that small amounts of oxygen replacement can reduce the NOx emissions as compared to the air-alone system. NOx emissions significantly below 0.15 lbs/MMBtu were measured. Oxygen addition was also shown to reduce carbon in ash. Comparison of the costs of using oxygen for NOx control against competing technologies, such as SCR, show that this concept offers substantial savings over SCR and is an economically attractive alternative to purchasing NOx credits or installing other conventional technologies. In conjunction with the development of oxygen based low NOx technology, Praxair also worked on developing the economically enhancing oxygen transport membrane (OTM) technology which is ideally suited for integration with combustion systems to achieve further significant cost reductions and efficiency improvements. This OTM oxygen production technology is based on ceramic mixed conductor membranes that operate at high temperatures and can be operated in a pressure driven mode to separate oxygen with infinite selectivity and high flux. An OTM material was selected and characterized. OTM elements were successfully fabricated. A single tube OTM reactor was designed and assembled. Testing of dense OTM elements was conducted with promising oxygen flux results of 100% of target flux. However, based on current natural gas prices and stand-alone air separation processes, ceramic membranes do not offer an economic advantage for this application. Under a different DOE-NETL Cooperative Agreement, Praxair is continuing to develop oxygen transport membranes for the Advanced Boiler where the economics appear more attractive.

  16. Atomic oxygen patterning from a biomedical needle-plasma source

    SciTech Connect (OSTI)

    Kelly, Seán; Turner, Miles M. [School of Physical Science and National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland)] [School of Physical Science and National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland)

    2013-09-28T23:59:59.000Z

    A “plasma needle” is a cold plasma source operating at atmospheric pressure. Such sources interact strongly with living cells, but experimental studies on bacterial samples show that this interaction has a surprising pattern resulting in circular or annular killing structures. This paper presents numerical simulations showing that this pattern occurs because biologically active reactive oxygen and nitrogen species are produced dominantly where effluent from the plasma needle interacts with ambient air. A novel solution strategy is utilised coupling plasma produced neutral (uncharged) reactive species to the gas dynamics solving for steady state profiles at the treated biological surface. Numerical results are compared with experimental reports corroborating evidence for atomic oxygen as a key bactericidal species. Surface losses are considered for interaction of plasma produced reactants with reactive solid and liquid interfaces. Atomic oxygen surface reactions on a reactive solid surface with adsorption probabilities above 0.1 are shown to be limited by the flux of atomic oxygen from the plasma. Interaction of the source with an aqueous surface showed hydrogen peroxide as the dominant species at this interface.

  17. Neutrino and antineutrino energy loss rates in massive stars due to isotopes of titanium

    E-Print Network [OSTI]

    Nabi, Jameel-Un

    2011-01-01T23:59:59.000Z

    Weak interaction rates on titanium isotopes are important during the late phases of evolution of massive stars. A search was made for key titanium isotopes from available literature and a microscopic calculation of weak rates of these nuclei were performed using the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. Earlier the author presented the stellar electron capture rates on titanium isotopes. In this paper I present the neutrino and antineutrino energy loss rates due to capture and decay rates on isotopes of titanium in stellar environment. Accurate estimate of neutrino energy loss rates are needed for the study of the late stages of the stellar evolution, in particular for cooling of neutron stars and white dwarfs. The results are also compared against previous calculations. At high stellar temperatures the calculated neutrino and antineutrino energy loss rates are bigger by more than two orders of magnitude as compared to the large scale shell model results and favor stellar c...

  18. Oxygen and organic matter thresholds for benthic faunal activity on the Pakistan margin oxygen minimum zone (7001100 m)

    E-Print Network [OSTI]

    Levin, Lisa

    Oxygen and organic matter thresholds for benthic faunal activity on the Pakistan margin oxygen increased animal activity associated with increasing bottom-water oxygen concentration. We examined faunal community responses to oxygen and organic matter gradients across the lower oxygen minimum zone (OMZ

  19. Oxygen Discharge and Post-Discharge Kinetics Experiments and Modeling for the Electric Oxygen-Iodine Laser System

    E-Print Network [OSTI]

    Carroll, David L.

    Oxygen Discharge and Post-Discharge Kinetics Experiments and Modeling for the Electric Oxygen a low-pressure oxygen/helium/nitric oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited species adds levels

  20. Boundaries of the Peruvian Oxygen Minimum Zone shaped by coherent mesoscale dynamics

    E-Print Network [OSTI]

    Bettencourt, João H; García, Emilio Hernández; Montes, Ivonne; Sudre, Joël; Dewitte, Boris; Paulmier, Aurélien; Garçon, Véronique

    2015-01-01T23:59:59.000Z

    Dissolved oxygen in sea water is a major factor affecting marine habitats and biogeochemical cycles. Oceanic zones with oxygen deficits represent significant portions of the area and volume of the oceans and are thought to be expanding. The Peruvian oxygen minimum zone is one of the most pronounced and lies in a region of strong mesoscale activity in the form of vortices and frontal regions, whose effect in the dynamics of the oxygen minimum zone is largely unknown. Here, we study this issue from a modeling approach and a Lagrangian point of view, using a coupled physical-biogeochemical simulation of the Peruvian oxygen minimum zone and finite-size Lyapunov exponent fields to understand the link between mesoscale dynamics and oxygen variations. Our results show that, at depths between 380 and 600 meters, mesoscale structures have a relevant dual role. First, their mean positions and paths delimit and maintain the oxygen minimum zone boundaries. Second, their high frequency fluctuations entrain oxygen across t...