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1

Advances in studying bioinorganic reaction mechanisms: isotopic probes of activated oxygen  

E-Print Network [OSTI]

Advances in studying bioinorganic reaction mechanisms: isotopic probes of activated oxygen intermediates in metalloenzymes Justine P Roth Metalloenzymes catalyze reactions of molecular oxygen and its reduced forms through the controlled formation of metal- bound, activated oxygen intermediates

Roth, Justine P.

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

Isotope studies in photosynthesis  

Science Journals Connector (OSTI)

Isotope studies in photosynthesis ... Examines the use of isotopic oxygen, hydrogen, carbon, and phosphorus in the study of photosynthesis. ...

J. A. Bassham; A. A. Benson; Melvin Calvin

1953-01-01T23:59:59.000Z

4

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

Open Energy Info (EERE)

Oxygen Isotope Study Of Silicates In The Larderello Geothermal Field, Oxygen Isotope Study Of Silicates In The Larderello Geothermal Field, Italy Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: An Oxygen Isotope Study Of Silicates In The Larderello Geothermal Field, Italy Details Activities (0) Areas (0) Regions (0) Abstract: Stable-isotope analyses were carried out on hydrothermal minerals sampled from the deep metamorphic units at Larderello, Italy. The D18O values obtained for the most retentive minerals, quartz and tourmaline, are from + 12.0‰ to + 14.7‰ and 9.9‰, respectively, and indicate deposition from an 18O-rich fluid. Calculated D18O values for these fluids range from + 5.3‰ to + 13.4‰. These values, combined with available fluid inclusion and petrographic data, are consistent with the proposed

5

An Oxygen Isotope Study Of Hydrothermal Alteration In The Lake City  

Open Energy Info (EERE)

Isotope Study Of Hydrothermal Alteration In The Lake City Isotope Study Of Hydrothermal Alteration In The Lake City Caldera, San Juan Mountains, Colorado Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: An Oxygen Isotope Study Of Hydrothermal Alteration In The Lake City Caldera, San Juan Mountains, Colorado Details Activities (2) Areas (1) Regions (0) Abstract: A 23-m.y.-old, fossil meteoric-hydrothermal system in the Lake City caldera (11 _ 14 km) has been mapped out by measuring Δ 18O values of 300 rock and mineral samples. Δ 18O varies systematically throughout the caldera, reaching values as low as -2. Great topographic relief, regional tilting, and variable degrees of erosion within the caldera all combine to give us a very complete section through the hydrothermal system, from the

6

Respiration, photosynthesis, and oxygen isotope fractionation in ...  

Science Journals Connector (OSTI)

Jan 25, 1971 ... Respiration, photosynthesis, and oxygen isotope fractionation in oceanic surface water1. Peter M. Kroopnick. Department of Oceanography,.

2000-01-04T23:59:59.000Z

7

Photo-oxidation of Water by Molecular Oxygen: Isotope Exchange and Isotope Effects  

Science Journals Connector (OSTI)

In order to detect the reaction, we used water highly enriched with isotopes 17O and 18O, controlling the isotope composition of molecular oxygen before and after reaction. ... stability of heavy-isotope clumps'; slower kinetics of reactions requiring the breakage of bonds between heavy isotopes; the mass dependence of diffusive and thermo-gravitational fractionations; mixing between components that differ from one another in bulk isotopic compn.; biochem. ... Study of oxygen three-isotope behavior during thermal decompn. of naturally occurring carbonates of calcium and magnesium in vacuo revealed that, surprisingly, anomalous isotopic compns. ...

Anatoly L. Buchachenko; Elena O. Dubinina

2011-03-30T23:59:59.000Z

8

Device and method for separating oxygen isotopes  

DOE Patents [OSTI]

A device and method for separating oxygen isotopes with an ArF laser which produces coherent radiation at approximately 193 nm. The output of the ArF laser is filtered in natural air and applied to an irradiation cell where it preferentially photodissociates molecules of oxygen gas containing .sup.17 O or .sup.18 O oxygen nuclides. A scavenger such as O.sub.2, CO or ethylene is used to collect the preferentially dissociated oxygen atoms and recycled to produce isotopically enriched molecular oxygen gas. Other embodiments utilize an ArF laser which is narrowly tuned with a prism or diffraction grating to preferentially photodissociate desired isotopes. Similarly, desired mixtures of isotopic gas can be used as a filter to photodissociate enriched preselected isotopes of oxygen.

Rockwood, Stephen D. (Los Alamos, NM); Sander, Robert K. (Los Alamos, NM)

1984-01-01T23:59:59.000Z

9

Oxygen isotope study of the Long Valley magma system, California: isotope thermometry and convection in large silicic magma bodies  

Science Journals Connector (OSTI)

Products of voluminous pyroclastic eruptions with eruptive draw-down of several kilometers provide a snap-shot view of batholith-scale magma chambers, and quench pre-eruptive isotopic fractionations (i.e., temper...

Ilya N. Bindeman; John W. Valley

2002-11-01T23:59:59.000Z

10

Geothermal reservoir temperatures estimated from the oxygen isotope  

Open Energy Info (EERE)

reservoir temperatures estimated from the oxygen isotope reservoir temperatures estimated from the oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Geothermal reservoir temperatures estimated from the oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes Details Activities (3) Areas (3) Regions (0) Abstract: The oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes have been tested as a geothermometer in three areas of the western United States. Limited analyses of spring and borehole fluids and existing experimental rate studies suggest that dissolved sulfate and water are probably in isotopic equilibrium in all reservoirs of significant size with temperatures above

11

Oxygen isotope records of carboniferous seasonality on the Russian platform  

E-Print Network [OSTI]

OXYGEN ISOTOPE RECORDS OF CARBONIFEROUS SEASONALITY ON THE RUSSIAN PLATFORM A Thesis by HUAYU WANG 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 May 1998 Major Subject: Geology OXYGEN ISOTOPE RECORDS OF CARBONIFFROUS SEASONALITY ON THE RUSSIAN PLATFORM A Thesis by HUAYU WANG Submitted to Texas ARM University in partial fulfillment of the requirements for the degree of MASTER...

Wang, Huayu

2012-06-07T23:59:59.000Z

12

Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone  

Open Energy Info (EERE)

Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone Drill Cores Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone Drill Cores Details Activities (3) Areas (1) Regions (0) Abstract: Oxygen and carbon isotope ratios were measured for hydrothermal minerals (silica, clay and calcite) from fractures and vugs in altered rhyolite, located between 28 and 129 m below surface (in situ temperatures ranging from 81 to 199°C) in Yellowstone drill holes. The purpose of this study was to investigate the mechanism of formation of these minerals. The Δ18O values of the thirty-two analyzed silica samples (quartz, chalcedony, α-cristobalite, and β-cristobalite) range from -7.5 to +2.8‰. About one

13

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

E-Print Network [OSTI]

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

Chakraborty, Subrata

2013-01-01T23:59:59.000Z

14

It's Elemental - Isotopes of the Element Oxygen  

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

Nitrogen Nitrogen Previous Element (Nitrogen) The Periodic Table of Elements Next Element (Fluorine) Fluorine Isotopes of the Element Oxygen [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 16 99.757% STABLE 17 0.038% STABLE 18 0.205% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 12 1.139×10-21 seconds Proton Emission No Data Available 13 8.58 milliseconds Electron Capture 100.00% Electron Capture with delayed Proton Emission 100.00% 14 70.620 seconds Electron Capture 100.00% 15 122.24 seconds Electron Capture 100.00% 16 STABLE - - 17 STABLE - - 18 STABLE - - 19 26.88 seconds Beta-minus Decay 100.00%

15

The Oxygen core inside the Magnesium isotopes  

E-Print Network [OSTI]

We have studied the ground state bulk properties of magnesium isotopes using axially symmetric relativistic mean field formalism. The BCS pairing approach is employed to take care of the pairing correlation for the open shell nuclei. The contour plot of the nucleons distribution are analyzed at various parts of the nucleus, where clusters are located. The presence of an $^{16}$O core along bubble like $\\alpha$-particle(s) and few {\\it nucleons} are found in the Mg isotopes.

Bhuyan, M

2013-01-01T23:59:59.000Z

16

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 GEOTHERMAL...

17

Oxygen isotope analysis of multiple, single ostracod valves as a proxy for combined variability in seasonal temperature and lake water oxygen isotopes  

Science Journals Connector (OSTI)

Paleoclimate studies in lakes typically use oxygen isotopic ratios in samples that consist of multiple ostracod specimens, to obtain an average ?18O value that reflects the mean temperature and ?18O of lake water...

Yama Dixit; David A. Hodell; Rajiv Sinha; Cameron A. Petrie

2014-10-01T23:59:59.000Z

18

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

19

Hydrogen, Oxygen and Silicon Isotope Systematics in Lunar Material  

Science Journals Connector (OSTI)

31 March 1977 research-article Hydrogen, Oxygen and Silicon Isotope Systematics...are supported: (1) The bulk of the hydrogen in the lunar soils represents protons...samples of relatively detuerium rich hydrogen are found, probably resulting from in...

1977-01-01T23:59:59.000Z

20

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

E-Print Network [OSTI]

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

Chan, Sharleen

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Oxygen-Isotope Exchange between CO2 and Solid Ti18O2  

Science Journals Connector (OSTI)

Oxygen-Isotope Exchange between CO2 and Solid Ti18O2 ... Analysis of the isotopic composition of the gases produced has revealed ... ...

Svatopluk Civis?; Martin Ferus; Pavel Kuba?t; Marke?ta Zukalova?; Ladislav Kavan

2011-05-17T23:59:59.000Z

22

INTRODUCTION The oxygen isotopic compositions of minerals  

E-Print Network [OSTI]

- perature and aridity is not so well understood. Because the middle Holocene was a period of elevated solar of the Gulf of Mexico, Pacific, andArctic air masses (Bryson, 1966; Fig. 1). Gulf of Mexico air sup- plies of Mexico air masses and its precipitation is isotopically more negative than gulf moisture (e.g., typically

González, Luis A.

23

Atmospheric Oxygen: Isotopic Composition and Solubility Fractionation  

Science Journals Connector (OSTI)

...where the subscripts aq and gas refer to the aqueous phase and the gas phase, respectively. The single-stage...adsorption and desorp-tion of oxygen gas on type SA molecular sieve...material seems to be debris of the Cyprus-sized planetesimal that produced...

P. Kroopnick; H. Craig

1972-01-07T23:59:59.000Z

24

Exploring Neutron-Rich Oxygen Isotopes with MoNA  

E-Print Network [OSTI]

The Modular Neutron Array (MoNA) was used in conjunction with a large-gap dipole magnet (Sweeper) to measure neutron-unbound states in oxygen isotopes close to the neutron dripline. While no excited states were observed in 24O, a resonance at 45(2) keV above the neutron separation energy was observed in 23O.

N. Frank; T. Baumann; D. Bazin; J. Brown; P. A. DeYoung; J. E. Finck; A. Gade; J. Hinnefeld; R. Howes; J. -L. Lecouey; B. Luther; W. A. Peters; H. Scheit; A. Schiller; M. Thoennessen

2007-08-20T23:59:59.000Z

25

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

26

Competitive oxygen-18 kinetic isotope effects expose OO bond formation in water oxidation  

E-Print Network [OSTI]

Competitive oxygen-18 kinetic isotope effects expose O­O bond formation in water oxidation. Roth*a Competitive oxygen kinetic isotope effects (18 O KIEs) on water oxidation initiated by ruthenium during oxygenic photo- synthesis.1 Formation of the O­O bond in molecular oxygen has been proposed

Roth, Justine P.

27

Stable isotope studies  

SciTech Connect (OSTI)

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.

Ishida, T.

1992-01-01T23:59:59.000Z

28

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

E-Print Network [OSTI]

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

Roth, Justine P.

29

Ice-free conditions in Sweden during Marine Oxygen Isotope Stage 3? BARBARA WOHLFARTH  

E-Print Network [OSTI]

Ice-free conditions in Sweden during Marine Oxygen Isotope Stage 3? BARBARA WOHLFARTH BOREAS Wohlfarth, B. 2010 (April): Ice-free conditions in Sweden during Marine Oxygen Isotope Stage 3? Boreas, Vol dates for Sweden older than the Last Glacial Maximum ice advance were eval- uated. Acceptable 14 C dates

Wohlfarth, Barbara

30

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...

31

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

E-Print Network [OSTI]

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

Grossman, Lawrence

32

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

E-Print Network [OSTI]

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.

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

2008-03-05T23:59:59.000Z

33

Carbon and oxygen isotope stratigraphy of the oxfordian carbonate rocks in Amu Darya basin  

Science Journals Connector (OSTI)

Based on the detailed research on petrologic and geochemical characteristics of deposition and diagenesis of Oxfordian carbonate rocks in Amu Darya Basin, Turkmenistan, carbon and oxygen isotopes were analyzed...

Rongcai Zheng ???; Yanghui Pan ???; Can Zhao ??; Lei Wu ??

2013-02-01T23:59:59.000Z

34

Oxygen Isotope Exchange Between Refractory Inclusion in Allende and Solar Nebula Gas  

Science Journals Connector (OSTI)

...in Fig. 2. Figure 2 Distribution of akermanite contents (mol %) and oxygen isotope...O-poor region, whereas an obvious akermanite content gap is not observed at the contact. The akermanite content increases near and at the grain...

Hisayoshi Yurimoto; Motoo Ito; Hiroshi Nagasawa

1998-12-04T23:59:59.000Z

35

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

E-Print Network [OSTI]

Holocene Paleohydrology and Paleoclimate at Treeline, North-Central Russia, Inferred from Oxygen Institute for Geography, Russian Academy of Sciences, Staromonetny Pereulok 29, Moscow 109017, Russia, 1998 Lake-water oxygen-isotope histories for three lakes in northern Russia, derived from the cellulose

Edwards, Thomas W.D.

36

Oxygen Isotope Evidence For Past And Present Hydrothermal Regimes Of Long  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Oxygen Isotope Evidence For Past And Present Hydrothermal Regimes Of Long Valley Caldera, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Oxygen Isotope Evidence For Past And Present Hydrothermal Regimes Of Long Valley Caldera, California Details Activities (3) Areas (1) Regions (0) Abstract: Whole-rock oxygen isotope compositions of cores and cuttings from Long Valley exploration wells show that the Bishop Tuff has been an important reservoir for both fossil and active geothermal systems within the caldera. The deep Clay Pit-1 and Mammoth-1 wells on the resurgent dome

37

Holocene hydrologic balance of tropical South America from oxygen isotopes of lake sediment opal, Venezuelan Andes  

E-Print Network [OSTI]

Holocene hydrologic balance of tropical South America from oxygen isotopes of lake sediment opal is derived from Atlantic Ocean evaporation which is modified by passage over lowland South America suggest that the decreasing 18 O reflects a decrease in the fraction of moisture entering South America

Wolfe, Alexander P.

38

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

E-Print Network [OSTI]

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...

Kobashi, Takuro

2012-06-07T23:59:59.000Z

39

Modern stalagmite oxygen isotopic composition and its implications of climatic change from a high-elevation cave in the eastern Qinghai-Tibet Plateau over the past 50 years  

E-Print Network [OSTI]

Yuan D X, Qin J M, et al. Oxygen and carbon isotopic charac-R L, Wang X F, et al. Oxygen isotopic records of stalagmitesVerlag Modern stalagmite oxygen isotopic composition and its

2007-01-01T23:59:59.000Z

40

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

E-Print Network [OSTI]

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. In the case of the calcium isotopes, the drip line is predicted to be reached beyond ${}^{60}$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.

Wei-Chia Chen; J. Piekarewicz

2014-12-25T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

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

E-Print Network [OSTI]

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.

A. Cipollone; C. Barbieri; P. Navrtil

2014-12-01T23:59:59.000Z

42

Depletion of heavy isotopes of oxygen and hydrogen in tissue water of intertidal plants: implications for water economy  

Science Journals Connector (OSTI)

Stable oxygen and hydrogen isotope ratios of leaf and thallus water of the intertidal seagrasses Phyllospadix scouleri and P. torreyi and the marine algae Egregia menziesii, Gelidium coulteri, and Corallina vanco...

L. W. Cooper; M. J. DeNiro

1989-05-01T23:59:59.000Z

43

Mechanistic studies using kinetic isotope effects  

E-Print Network [OSTI]

MECHANISTIC STUDIES USING KINETIC ISOTOPE EFFECTS A Thesis by BRIAN E. SCHULMFIER Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requtrements for the degree of MASTER OF SCIENCE December... 1999 Major Subject: Chemistry MECHANISTIC STUDIES USING KINETIC ISOTOPE EFFECTS A Thesis by BRIAN E. SCHULMEIER Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved...

Schulmeier, Brian E.

2012-06-07T23:59:59.000Z

44

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

E-Print Network [OSTI]

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...

Wagner, Amy Jo

2011-02-22T23:59:59.000Z

45

Helium and oxygen isotope analyses of hydrothermal fluids from the East Pacific Rise between 17S and 19S  

Science Journals Connector (OSTI)

?Hydrothermal vent fields south of the Garret Fracture zone were sampled for the isotope composition of helium and oxygen ([18O]H2O/[16OH2O). The helium isotopes end-member (3He?/?4He=8.3R ...

P. Jean-Baptiste; A. Dapoigny; M. Stievenard; J. L. Charlou

1997-08-01T23:59:59.000Z

46

Determination of oxygen self-diffusion in akermanite, anorthite, diopside, and spinel: Implications for oxygen isotopic anomalies and the thermal histories of Ca-Al-rich inclusions  

SciTech Connect (OSTI)

Oxygen self-diffusion coefficients have been measured for three natural diopsidic clinopyroxenes, a natural anorthite, a synthetic magnesium aluminate spinel, and a synthetic akermanite for oxygen fugacities ranging from the NNO to IW buffers. The oxygen diffusion data are used to evaluate the effects of three different types of thermal histories upon the oxygen isotopic compositions of minerals found in Type B Ca-Al-rich inclusions (CAIBs) in carbonaceous chondrites: (1) gas-solid exchange during isothermal heating, (2) gas-solid exchange as a function of cooling rate subsequent to instantaneous heating, and (3) isotopic exchange with a gaseous reservoir during partial melting and recrystallization. With the assumptions that the mineral compositions within a CAIB were uniformly enriched in [sup 16]O prior to any thermal processing, that effective diffusion dimensions may be estimated from observed grain sizes, and that diffusion in diopside is similar to that in fassaitic clinopyroxene, none of the above scenarios can reproduce the relative oxygen isotopic anomalies observed in CAIBs without improbably long or unrealistically intense thermal histories relative to current theoretical models of nebular evolution. The failure of these simple models, coupled with recent observations of disturbed magnesium isotopic abundances and correlated petrographic features in anorthite and melilite indicative of alteration and recrystallization, suggests that the oxygen isotopic compositions of these phases may have also been modified by alteration and recrystallization possibly interspersed with multiple melting events. Because the modal abundance of spinel remains relatively constant for plausible melting scenarios, and its relatively sluggish diffusion kinetics prevent substantial equilibration, Mg-Al spinel is the most reliable indicator of the oxygen isotopic composition of precursor material which formed Type B CAIs.

Ryerson, F.J. (Lawrence Livermore National Lab., CA (United States)); McKeegan, K.D. (Univ. of California, Los Angeles, CA (United States))

1994-09-01T23:59:59.000Z

47

OXYGEN ISOTOPIC COMPOSITIONS OF THE ALLENDE TYPE C CAIs: EVIDENCE FOR ISOTOPIC EXCHANGE DURING NEBULAR MELTING AND ASTEROIDAL THERMAL METAMORPHISM  

SciTech Connect (OSTI)

Based on the mineralogy and petrography, coarse-grained, igneous, anorthite-rich (Type C) calcium-aluminum-rich inclusions (CAIs) in the CV3 carbonaceous chondrite Allende have been recently divided into three groups: (i) CAIs with melilite and Al,Ti-diopside of massive and lacy textures (coarse grains with numerous rounded inclusions of anorthite) in a fine-grained anorthite groundmass (6-1-72, 100, 160), (ii) CAI CG5 with massive melilite, Al,Ti-diopside and anorthite, and (iii) CAIs associated with chondrule material: either containing chondrule fragments in their peripheries (ABC, TS26) or surrounded by chondrule-like, igneous rims (93) (Krot et al., 2007a,b). Here, we report in situ oxygen isotopic measurements of primary (melilite, spinel, Al,Ti-diopside, anorthite) and secondary (grossular, monticellite, forsterite) minerals in these CAIs. Spinel ({Delta}{sup 17}O = -25{per_thousand} to -20{per_thousand}), massive and lacy Al,Ti-diopside ({Delta}{sup 17}O = -20{per_thousand} to -5{per_thousand}) and fine-grained anorthite ({Delta}{sup 17}O = -15{per_thousand} to -2{per_thousand}) in 100, 160 and 6-1-72 are {sup 16}O-enriched relative spinel and coarse-grained Al,Ti-diopside and anorthite in ABC, 93 and TS26 ({Delta}{sup 17}O ranges from -20{per_thousand} to -15{per_thousand}, from -15{per_thousand} to -5{per_thousand}, and from -5{per_thousand} to 0{per_thousand}, respectively). In 6-1-72, massive and lacy Al,Ti-diopside grains are {sup 16}O-depleted ({Delta}{sup 17}O {approx} -13{per_thousand}) relative to spinel ({Delta}{sup 17}O = -23{per_thousand}). Melilite is the most {sup 16}O-depleted mineral in all Allende Type C CAIs. In CAI 100, melilite and secondary grossular, monticellite and forsterite (minerals replacing melilite) are similarly {sup 16}O-depleted, whereas grossular in CAI 160 is {sup 16}O-enriched ({Delta}{sup 17}O = -10{per_thousand} to -6{per_thousand}) relative to melilite ({Delta}{sup 17}O = -5{per_thousand} to -3{per_thousand}). We infer that CAIs 100, 160 and CG5 experienced melting in an {sup 16}O-rich ({Delta}{sup 17}O < -20{per_thousand}) nebular gas in the CAI-forming region. The Type C and Type-B-like portions of CAI 6-1-72 experienced melting in an {sup 16}O-depleted ({Delta}{sup 17}O {ge} -13{per_thousand}) nebular gas. CAIs ABC, TS26 and 93 experienced isotopic exchange during re-melting in the presence of an {sup 16}O-poor ({Delta}{sup 17}O {ge} -10{per_thousand}) nebular gas in the chondrule-forming region(s). Subsequently, Allende Type C CAIs experienced post-crystallization isotopic exchange with an {sup 16}O-poor reservoir that affected largely melilite and anorthite. Because pseudomorphic replacement of lacy melilite by grossular, monticellite and forsterite occurred during thermal metamorphism, some oxygen isotopic exchange of melilite and anorthite must have continued after formation of these secondary minerals. We suggest that some or all oxygen isotopic exchange in melilite and anorthite occurred during fluid-assisted thermal metamorphism on the CV parent asteroid. Similar processes may have also affected melilite and anorthite of CAIs in metamorphosed CO chondrites.

Krot, A N; Chaussidon, M; Yurimoto, H; Sakamoto, N; Nagashima, K; Hutcheon, I D; MacPherson, G J

2008-02-21T23:59:59.000Z

48

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]

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

Gates, Kent. S.

49

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]

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

Grossman, Lawrence

50

Continuum Effects and Three-Nucleon Forces in Neutron-Rich Oxygen Isotopes  

SciTech Connect (OSTI)

We employ interactions from chiral effective field theory and compute binding energies, excited states, and radii for isotopes of oxygen with the coupled-cluster method. Our calculation includes the effects of three-nucleon forces and of the particle continuum, both of which are important for the description of neutron-rich isotopes in the vicinity of the nucleus 24O. Our main results are the placement of the neutron drip-line at 24O, the assignment of spins, parities and resonance widths for several low-lying states of the drip-line nucleus, and an efficient approximation that incorporates the effects of three-body interactions.

Hagen, Gaute [ORNL; Hjorth-Jensen, M. [University of Oslo, Norway; Jansen, G R [University of Oslo, Norway; Machleidt, R [University of Idaho; Papenbrock, T. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)

2012-01-01T23:59:59.000Z

51

Density Functional Theory Study of Oxygen Reduction Activity...  

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

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

52

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...

53

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...

54

Post-eruptive alteration of silicic ignimbrites and lavas, Gran Canaria, Canary Islands: Strontium, neodymium, lead, and oxygen isotopic evidence  

SciTech Connect (OSTI)

Isotopic analyses of Miocene comenditic, pantelleritic, and trachyphonolitic ignimbrites and lavas from Gran Canaria, Canary Islands, provide evidence for posteruptive mobility of Rb, Sr, and O. Calculated initial [sup 87]Sr/[sup 86]Sr ratios in whole-rock samples from basaltic lavas and feldspar mineral separates from ignimbrites define a magmatic trend in the stratigraphic section, from ratios of 0.70340 at the base of the Mogan Formation to 0.70305 in the lower Fataga Formation. However, calculated apparent initial [sup 87]Sr/[sup 86]Sr ratios in hydrated vitrophyre and devitrified matrix separates range from 0.7035 to 0.7090. [delta][sup 18]O ratios in basalts and feldspars vary little, from +5.7 to +6.1, yet range from +6.5 to +15.0 in the ignimbrite matrices. In contrast to the Sr and O isotope ratios, Pb and Nd isotope ratios are identical within analytical error in feldspars and their silicic ignimbrite matrices. Sequential leaching experiments and the oxygen data suggest that low-temperature, posteruptive interaction with meteoric water, perhaps containing a small seawater component, has modified Rb and Sr concentrations in the matrices, such that calculated apparent initial [sup 87]Sr/[sup 86]Sr ratios are not those of the magmas when they were erupted. Mobilization of Rb and Sr must occur significantly after eurption. Nd and Pb isotope systems appear to be unaffected by this process. Therefore, [sup 87]Sr/[sup 86]Sr ratios determined by whole rock analysis of silicic rocks from hotspot-type oceanic islands are suspect and should not be incorporated into mantle tracer studies, although analysis of phenocrysts may produce useful data. 40 refs., 5 figs., 3 tabs.

Cousens, B.L. (Universite de Montreal, Quebec (Canada)); Spera, F.J. (Univ. of California, Santa Barbara (United States)); Dobson, P.F. (Unocal Corp., Brea, CA (United States))

1993-02-01T23:59:59.000Z

55

RADIOCHEMICAL STUDIES OF NEUTRON DEFICIENT ACTINIDE ISOTOPES  

E-Print Network [OSTI]

Isotope Targets and Foils, AERE-R 5097, Paper 10 (1965). V.Isotope Targets and Foils, AERE-R 5097 Paper 12 (1965). K.M.Isotope Targets and Foils, AERE-R-5097 Paper 11 (1965). M.

Williams, Kimberly Eve

2011-01-01T23:59:59.000Z

56

Deuterium and oxygen-18 isotope effects on nucleophilic displacement by water  

SciTech Connect (OSTI)

Kinetic deuterium isotope effects (k/sub H/sub 2/O//k/sub D/sub 2/O/) have been measured for nucleophilic attack by water at primary alkyl carbon (S-methylthiophenium ion (MeTh+), methyl trifluoromethane-sulfonate (MeOTf), methyl and ethyl perchlorate (MeOClO/sub 3/, EtOClO/sub 3/)) in aprotic solvents (acetonitrile (MeCN) and tetrahydrothiophene-1, 1-dioxide (TMSO/sub 2/; solfolane)) and L/sub 2/O. In L/sub 2/O solvent k/sub H/sub 2/O//k/sub D/sub 2/O/ is significantly greater than unity while it is reduced to near unity in aprotic solvents. The oxygen-18 isotope effect has also been observed to be 1.002 +- 0.004 for the reaction of MeTh/sup +/ with dilute H/sub 2/O in TMSO/sub 2/ at 35/sup 0/C. For the reaction of MeTh/sup +/ and MeOClO/sub 3/ in aprotic solvents the chemical reaction kinetics are discussed.

Lee, J.

1981-01-01T23:59:59.000Z

57

Phosphate oxygen isotope ratios as a tracer for sources and cycling of phosphate in North San Francisco Bay, California  

E-Print Network [OSTI]

and restoration of these ecosystems. [3] Phosphorus (P) is a required element for life and consequently, its is low relative to input and phosphate is not heavily cycled in the ecosystem, the oxygen isotopic.1029/2005JG000079. 1. Introduction [2] Urban and agricultural runoff are major sources of phosphate to aquatic

Paytan, Adina

58

Use of Oxygen Isotopic Exchange to Explore Catalytic Activity and the Mechanism of Oxygen Reduction on Oxides.  

E-Print Network [OSTI]

??The electrochemical performance of intermediate temperature solid oxide fuel cells is limited by high polarization losses incurred from the oxygen reduction reaction at the cathode. (more)

Kan, Cynthia

2009-01-01T23:59:59.000Z

59

Oxygen reduction on platinum : an EIS study  

E-Print Network [OSTI]

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 ...

Golfinopoulos, Theodore

2009-01-01T23:59:59.000Z

60

Oxygen isotope records of the Australian flat oyster (Ostrea angasi) as a potential temperature archive  

Science Journals Connector (OSTI)

Abstract The response of the oxygen isotope ratio (?18O) in shells of the Australian native flat oyster Ostrea angasi to changes in water temperature has been assessed using growth experiments conducted for one year at two locations on the east coast of Australia. The analysed ?18O of the oyster shells (?18Oshell) closely follows the predicted oyster shell ?18O constructed from measured ?18O in the water (?18Owater) and water temperature. Influxes of freshwater that occur in the estuarine habitats of O. angasi can modify the ?18Owater, and consequently ?18Oshell. Salinity fluctuations can also cause interruptions to shell growth in this species. This can cause overestimated temperatures in O. angasi ?18Oshell temperature reconstructions. A ?18Oshelltemperature calibration was established for O. angasi, yielding the relationship: TC=13.97?(3.57?18Oshell??18Owater)+(0.17?18Oshell??18Owater)2, n=79, R2=0.79, which, within the experimental uncertainties of the data, is similar to other published biogenic carbonate paleotemperature equations.

Sarah Tynan; Andrea Dutton; Stephen Eggins; Bradley Opdyke

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Oxygen isotope analysis of California mussel shells: seasonality and human sedentism at an 8,200-year-old shell midden on Santa Rosa Island, California  

Science Journals Connector (OSTI)

To evaluate coastal settlement and land use strategies among maritime hunter-gatherers, we analyzed oxygen isotope (?18O) data from 131 marine carbonate samples from 21 California mussel (Mytilus californianus) s...

Nicholas P. Jew; Jon M. Erlandson

2014-09-01T23:59:59.000Z

62

Effects of nitrate and water on the oxygen isotopic analysis of barium sulfate precipitated from  

E-Print Network [OSTI]

on an anion-exchange resin such as IRA-4005 before being precipitated as BaSO4. Isotopic analyses of O (d18 O by (1) ion chromatographic separation of SO4 2S from NO3 S , (2) increasing the salinity- ing H2O and NO3 S . These procedures are demonstrated for SO4 2S isotopic reference materials

63

Isotope Analysis  

Science Journals Connector (OSTI)

Naturally occurring oxygen includes three stable isotopes,16O,17O, and18O, with the relative abundances of 99.763%, 0.0375%, and 0.1995%, respectively. Isotopic analysis does not consider the absolute abundances ...

Tandong Yao; Wusheng Yu; Huabiao Zhao

2014-08-01T23:59:59.000Z

64

DME-to-oxygenates process studies  

SciTech Connect (OSTI)

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.

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

65

Isotopic Analysis- Fluid At Fenton Hill HDR Geothermal Area ...  

Open Energy Info (EERE)

samples analyzed during this investigation were analyzed for their hydrogen and oxygen isotope contents as a part of previous studies (Goff & Grigsby, 1982; Vuataz & Goff, 1986)....

66

Isotopic Analysis- Fluid At Valles Caldera - Sulphur Springs...  

Open Energy Info (EERE)

samples analyzed during this investigation were analyzed for their hydrogen and oxygen isotope contents as a part of previous studies (Goff & Grigsby, 1982; Vuataz & Goff, 1986)....

67

Isotopic Analysis- Fluid At Valles Caldera - Redondo Area (Rao...  

Open Energy Info (EERE)

samples analyzed during this investigation were analyzed for their hydrogen and oxygen isotope contents as a part of previous studies (Goff & Grigsby, 1982; Vuataz & Goff, 1986)....

68

A Strontium Isotopic Study Of Newberry Volcano, Central Oregon- Structural  

Open Energy Info (EERE)

Strontium Isotopic Study Of Newberry Volcano, Central Oregon- Structural Strontium Isotopic Study Of Newberry Volcano, Central Oregon- Structural And Thermal Implications Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Strontium Isotopic Study Of Newberry Volcano, Central Oregon- Structural And Thermal Implications Details Activities (2) Areas (1) Regions (0) Abstract: Ratios of 87Sr/86Sr were determined in twenty-seven basaltic rocks from Newberry. These ratios range from 0.70330 to 0.70414; most fall between 0.7035 and 0.7038. Covariance of Al2O3/FeO* ratio, TiO2 content, and Th content with 87Sr/86Sr suggests that some isotopic ratios reflect shallow crustal contamination, but the data also suggest that two mantle sources, a prominent one at 0.7036 and a less-prominent one at 0.7033 or less, are represented. The hypothesis of crustal contamination is supported

69

Preliminary study: isotopic safeguards techniques (IST) LMFBR fuel cycles  

SciTech Connect (OSTI)

This memorandum presents the preliminary results of the effort to investigate the applicability of isotope correlation techniques (ICT), formulated for the LWR system, to the LMFBR fuel cycle. The detailed isotopic compositional changes with burnup developed for the CRBR was utilized as the reference case. This differs from the usual LMFBR design studies in that the core uranium is natural uranium rather than depleted. Nevertheless, the general isotopic behavior should not differ significantly and does allow an initial insight into the expected behavior of isotopic correlations for the LMFBR power systems such as: the U.K. PFR and reprocessing plant; the French Phenix and Superphenix; and the US reference conceptual design studies (CDS) of homogeneous and heterogeneous LMFBR systems as they are developed.

Persiani, P.J.; Kroc, T.K.

1980-06-01T23:59:59.000Z

70

A rapid and precise method for sampling and determining the oxygen isotope ratio of atmospheric  

E-Print Network [OSTI]

2002; Accepted 1 March 2002 A quantitative method for cryogenically sampling atmospheric water vapor recovery of a vaporized, known, 18 O water standard to 0.2% precision. Copyright # 2002 John Wiley & Sons differentially affect both the concentration and isotope ratio of atmospheric water vapor.5,8,9 Measurements

Ehleringer, Jim

71

Oxygen- and Hydrogen-Isotopic Ratios of Water in Precipitation: Beyond Paleothermometry  

Science Journals Connector (OSTI)

...of water can be used to test Earth-system models focused on the hydrologic cycle...of the hydrologic cycles of Earth-system models that include appropriate isotopic...testing hydrologic cycles in Earth system models; this direction will be most...

Richard B. Alley; Kurt M. Cuffey

72

Solid phases of spatially nanoconfined oxygen: A neutron scattering study  

SciTech Connect (OSTI)

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.

Kojda, Danny [Helmholtz-Zentrum Berlin fr Materialien und Energie GmbH, 14109 Berlin (Germany) [Helmholtz-Zentrum Berlin fr Materialien und Energie GmbH, 14109 Berlin (Germany); Freie Universitt Berlin, 14195 Berlin (Germany); Wallacher, Dirk; Hofmann, Tommy, E-mail: tommy.hofmann@helmholtz-berlin.de [Helmholtz-Zentrum Berlin fr Materialien und Energie GmbH, 14109 Berlin (Germany)] [Helmholtz-Zentrum Berlin fr 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 Universitt Hamburg-Harburg, 21073 Hamburg (Germany)] [Technische Universitt Hamburg-Harburg, 21073 Hamburg (Germany)

2014-01-14T23:59:59.000Z

73

Identification of isotopically primitive interplanetary dust particles: A NanoSIMS isotopic imaging study  

E-Print Network [OSTI]

Identification of isotopically primitive interplanetary dust particles: A NanoSIMS isotopic imaging contain larger regions with more modest enrichments in 15 N, leading to average bulk N isotopic of those IDPs that have anomalous bulk N isotopic compositions. These particles typically also contain

74

Comparison of 105 years of oxygen isotope and insoluble impurity profiles from the Devon Island and Camp Century ice cores  

Science Journals Connector (OSTI)

Oxygen-isotope profiles for the Devon Island ice cap and Camp Century Greenland are affected by a number of variables, some of which must have been the same for both sites. The two ?(18O) records spanning about 120,000 years are brought into relative alignment by comparison of major ? features, and subsequent verification that the insoluble particulate concentration records were also in phase for this alignment. The difference between the ? profiles is shown to be mainly a function of the altitude of the accumulation area for Camp Century. This altitude seems to have been higher than present for the last 100,000 years, suggesting the present flow line through the site has never been shorter. The maximum altitude for the Camp Century accumulation area is 1500 m above the present site and is almost synchronous with the maximum in particulate concentration that occurs at 16,000 yr B.P. The synchronism is likely due to the maximum sea-level lowering that exposed vast areas of continental shelf to wind erosion.

David A. Fisher

1979-01-01T23:59:59.000Z

75

Deuterium and oxygen-18 isotope effects on nucleophilic displacement by monomeric water in aprotic solvents  

SciTech Connect (OSTI)

The H/sub 2/O/D/sub 2/O rate-constant ratio for nucleophilic attack by water at a methyl carbon (eq 1) is reduced to very near unity when the water is a dilute solute in L/sub 2/O+CH/sub 3/X..-->..L/sub 2/O/sup +/CH/sub 3/+X/sup -/ a dipolar aprotic solvent. This effect was observed for three leaving groups (CH/sub 3/X equals 1-methylthiophenium ion (MeTh/sup +/), methyl perchlorate (MeOCl/sub 3/), and methyl trifluoromethanesulfonate (MeOTf)) and for two aprotic solvents acetonitrile (MeCn), and tetrahydrothiophene 1,1-dioxide (TMSO:'';sulfolane). It was also observed that the corresponding H/sub 2//sup 16/O/H/sub 2//sup 18/O rate-constant ratio is 1.002 +- 0.004 (95% confidence limits) for the reaction of MeTh/sup +/ with dilute H/sub 2/O in TMSO/sub 2/ at 35/sup 0/C. Although alternative explanations exist (vide infra), these observations are consistent with a mechanism in which no significant positive charge is present on the L/sub 2/O oxygen in the rate-determining transition state and thus in which the rate-determining process does not involve (and is not preceded by) any significant covalent-bonding interaction between the nucleophile and the methyl carbon. All reactions were followed by uv spectroscopy in a Cary 16K spectrophotometer.

Kurz, J.L.; Lee, J.

1980-07-30T23:59:59.000Z

76

Ab-initio coupled-cluster effective interactions for the shell model: Application to neutron-rich oxygen and carbon isotopes  

E-Print Network [OSTI]

We derive and compute effective valence-space shell-model interactions from ab-initio coupled-cluster theory and apply them to open-shell and neutron-rich oxygen and carbon isotopes. Our shell-model interactions are based on nucleon-nucleon and three-nucleon forces from chiral effective-field theory. We compute the energies of ground and low-lying states, and find good agreement with experiment. In particular our calculations are consistent with the N=14, 16 shell closures in oxygen-22 and oxygen-24, while for carbon-20 the corresponding N=14 closure is weaker. We find good agreement between our coupled-cluster effective-interaction results with those obtained from standard single-reference coupled-cluster calculations for up to eight valence neutrons.

G. R. Jansen; J. Engel; G. Hagen; P. Navratil; A. Signoracci

2014-02-11T23:59:59.000Z

77

IAEA-CN-80/66 ISOTOPE TRACERS IN GLOBAL WATER AND CLIMATE STUDIES  

E-Print Network [OSTI]

comprehensive source of data for evaluating the modern global isotope field generated by atmospheric generalIAEA-CN-80/66 ISOTOPE TRACERS IN GLOBAL WATER AND CLIMATE STUDIES OF THE PAST AND PRESENT T Agency, Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, AUSTRIA Abstract ISOTOPE TRACERS IN GLOBAL WATER

Edwards, Thomas W.D.

78

Fusion of neutron-rich oxygen isotopes in the crust of accreting neutron stars  

Science Journals Connector (OSTI)

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?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 O24+O24 and Ne28+Ne28. 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 O24+O24 fusion and find that O24 should burn at densities near 1011 g/cm3. The energy released from this and similar reactions may be important for the temperature profile of the star.

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

2008-04-29T23:59:59.000Z

79

Using Nitrogen and Oxygen Isotope Compositions of Nitrate to Distinguish Contaminant Sources in Hanford Soil and Groundwater  

E-Print Network [OSTI]

stable isotopes at the Hanford Site, WA: Environ. Sci.Contaminant Transport at the Hanford Site, WA: Vadose ZoneRev. 0, Lockheed Martin Hanford Corporation, Richland, WA.

Conrad, Mark

2008-01-01T23:59:59.000Z

80

Spectroscopic study of the ? phase of solid oxygen  

Science Journals Connector (OSTI)

The infrared spectrum of the ? phase of solid oxygen has been studied between room temperature and 20 K as a function of pressure up to 63 GPa. Besides the strong absorption in the fundamental O2 vibron mode and the broad doublet in the overtone region, another peak is detected in the far infrared region. The analysis of the overtone bands allows the determination of the density of states of the O2 vibron region which consists of two separated energy regions, including one the infrared and the other the Raman bands observed in the 15001650?cm-1 range. This result, consistent with the analysis of the other Raman and infrared bands at lower frequency, is interpreted on the basis of a crystal composed by a molecular unit formed by four oxygen atoms. This hypothesis explains the strong infrared absorption which is in contrast with the model of a crystal composed by diatomic oxygen molecules. Very thin crystalline slabs (measure the intensity of the strong infrared absorption at 15001550?cm-1. The measurement of the Raman spectrum as a function of the incident power and of the laser excitation frequency shows how the intensity and the frequency of the Raman lines are affected by the experimental conditions. Finally, a simple chain model provides indirect proof of our assignment of the low-frequency infrared mode and allows to rule out an association in polymeric units formed by more than four atoms even at pressures close to the insulator-metal transition.

Federico A. Gorelli; Lorenzo Ulivi; Mario Santoro; Roberto Bini

2001-02-20T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

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]

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

Ben-Arie, Jezekiel

82

Oxygen isotope fractionation effects in soil water via interaction with cations (Mg, Ca, K, Na) adsorbed to phyllosilicate clay minerals  

E-Print Network [OSTI]

) adsorbed to phyllosilicate clay minerals Erik Oerter a, , Kari Finstad a , Justin Schaefer b , Gregory R approaches to the measurement of the d18 O value of soil water. The adsorbed cation isotope effect may bear

Goldsmith, Greg

83

Stable-Isotope Studies Of Rocks And Secondary Minerals In A Vapor...  

Open Energy Info (EERE)

Stable-Isotope Studies Of Rocks And Secondary Minerals In A Vapor-Dominated Hydrothermal System At The Geysers, Sonoma County, California Jump to: navigation, search GEOTHERMAL...

84

Oxygen Atom Transfer and Oxidative Water Incorporation in Cuboidal Mn3MOn Complexes Based on Synthetic, Isotopic Labeling,  

E-Print Network [OSTI]

is performed by the oxygen-evolving center (OEC) of photo- system II (PSII).2 The OEC consists of a Mn4Ca, United States *S Supporting Information ABSTRACT: The oxygen-evolving complex (OEC) of photo- system IIOxygen Atom Transfer and Oxidative Water Incorporation in Cuboidal Mn3MOn Complexes Based

Goddard III, William A.

85

Stable isotopes of hydrogen and oxygen in surface water and ground water at selected sites on or near the Idaho National Engineering Laboratory, Idaho  

SciTech Connect (OSTI)

Relative stable isotopic ratios for hydrogen and oxygen compared to standard mean ocean water are presented for water from 4 surface-water sites and 38 ground-water sites on or near the Idaho National Engineering Laboratory (INEL). The surface-water samples were collected monthly from March 1991 through April 1992 and after a storm event on June 18, 1992. The ground-water samples either were collected during 1991 or 1992. These data were collected as part of the US Geological Survey`s continuing hydrogeological investigations at the INEL. The relative isotopic ratios of hydrogen and oxygen are reported as delta {sup 2}H ({delta}{sup 2}H) and as delta {sup 18}O ({delta}{sup 18}O), respectively. The values of {delta}{sup 2}H and {delta}{sup 18}O in water from the four surface-water sites ranged from -143.0 to -122 and from -18.75 to -15.55, respectively. The values of {delta}{sup 2}H and {delta}{sup 18}O in water from the 38 ground-water sites ranged from -141.0 to -120.0 and from -18.55 to -14.95, respectively.

Ott, D.S.; Cecil, L.D.; Knobel, L.L.

1994-11-01T23:59:59.000Z

86

Carbon Isotopes  

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

Atmospheric Trace Gases » Carbon Isotopes Atmospheric Trace Gases » Carbon Isotopes Carbon Isotopes Gateway Pages to Isotopes Data Modern Records of Carbon and Oxygen Isotopes in Atmospheric Carbon Dioxide and Carbon-13 in Methane 800,000 Deuterium Record and Shorter Records of Various Isotopic Species from Ice Cores Carbon-13 13C in CO Measurements from Niwot Ridge, Colorado and Montana de Oro, California (Tyler) 13C in CO2 NOAA/CMDL Flask Network (White and Vaughn) CSIRO GASLAB Flask Network (Allison, Francey, and Krummel) CSIRO in situ measurements at Cape Grim, Tasmania (Francey and Allison) Scripps Institution of Oceanography (Keeling et al.) 13C in CH4 NOAA/CMDL Flask Network (Miller and White) Northern & Southern Hemisphere Sites (Quay and Stutsman) Northern & Southern Hemisphere Sites (Stevens)

87

unstable isotope  

Science Journals Connector (OSTI)

unstable isotope, radioisotope ? unstabiles Isotop n, nichtstabiles Isotop, radioaktives Isotop, Radioisotop

2014-08-01T23:59:59.000Z

88

Isotopic studies of Yucca Mountain soil fluids and carbonate pedogenesis  

SciTech Connect (OSTI)

Secondary carbonates occurring within the soils, faults, and subsurface fractures of Yucca Mountain contain some of the best available records of paleoclimate and palehydrology for the potential radioactive waste repository site. This article discusses conceptual and analytical advances being made with regard to the interpretation of stable isotope data from pedogenic carbonates, specifically related to the {sup 13}C content of soil CO{sub 2}, CaCO{sub 3}, precipitation mechanisms, and isotopic fractionations between parent fluids and precipitating carbonates. The {sup 13}C content of soil carbon dioxide from Yucca Mountain and vicinity shows most of the usual patterns expected in such contexts: Decreasing {sup 13}C content with depth decreasing {sup 13}C with altitude and reduced {sup 13}C during spring. These patterns exist within the domain of a noisy data set; soil and vegetational heterogeneities, weather, and other factors apparently contribute to isotopic variability in the system. Several soil calcification mechanisms appear to be important, involving characteristic physical and chemical environments and isotopic fractionations. When CO{sub 2} loss from thin soil solutions is an important driving factor, carbonates may contain excess heavy isotopes, compared to equilibrium precipitation with soil fluids. When root calcification serves as a proton generator for plant absorption of soil nutrients, heavy isotope deficiencies are likely. Successive cycles of dissolution and reprecipitation mix and redistribute pedogenic carbonates, and tend to isotopically homogenize and equilibrate pedogenic carbonates with soil fluids.

McConnaughey, T.A.; Whelan, J.F.; Wickland, K.P.; Moscati, R.J.

1994-12-31T23:59:59.000Z

89

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

Office of Scientific and Technical Information (OSTI)

and J.G. Whipple, Test and Evaluation o f Polymeric Membranes for Oxygen-Enrichment of Air, DOEAD- 127 10- 1, U S . Department of Energy, 1989. Sawyer, R.F., N.P. Cemansky, and...

90

Feasibility study of medical isotope production at Sandia National Laboratories  

SciTech Connect (OSTI)

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.

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

91

Isotopic Analysis- Fluid At Sierra Valley Geothermal Area (1990) | Open  

Open Energy Info (EERE)

Isotopic Analysis- Fluid At Sierra Valley Geothermal Area (1990) Isotopic Analysis- Fluid At Sierra Valley Geothermal Area (1990) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Sierra Valley Geothermal Area (1990) Exploration Activity Details Location Sierra Valley Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1990 Usefulness not indicated DOE-funding Unknown Exploration Basis Determine the recharge of the area Notes Hydrogen and oxygen isotope data on waters of Coso thermal and nonthermal waters were studied. Hydrogen and oxygen isotopes do not uniquely define the recharge area for the Coso geothermal system but strongly suggest Sierran recharge with perhaps some local recharge. References Whelan, J. A. (1 September 1990) Water geochemistry study of

92

Isotopic Analysis- Fluid At Rose Valley Geothermal Area (1990) | Open  

Open Energy Info (EERE)

Isotopic Analysis- Fluid At Rose Valley Geothermal Area (1990) Isotopic Analysis- Fluid At Rose Valley Geothermal Area (1990) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Rose Valley Geothermal Area (1990) Exploration Activity Details Location Rose Valley Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1990 Usefulness not indicated DOE-funding Unknown Exploration Basis Determine the recharge of the area Notes Hydrogen and oxygen isotope data on waters of Coso thermal and nonthermal waters were studied. Hydrogen and oxygen isotopes do not uniquely define the recharge area for the Coso geothermal system but strongly suggest Sierran recharge with perhaps some local recharge. References Whelan, J. A. (1 September 1990) Water geochemistry study of

93

Isotope studies of human remains from Mayutian, Yunnan Province, China  

Science Journals Connector (OSTI)

Abstract In order to examine human mobility during the first millennium BC in the Red River region of Southeast Asia, we examine strontium and stable isotopes in human dental enamel from the Mayutian site. We here report the initial results from this area. Local individuals have 87Sr/86Sr values of 0.70960.0003. The highest status individual of Mayutian is distinctly different (0.7066) suggesting a geographic origin further northwest, possibly near Dali. Stable isotopes reveal a mixture of C3 and C4 resources in the diet and indicate that they did not have an agricultural strategy that was dominated by either millet or rice.

Xingxiang Zhang; James Burton; Zhengyao Jin; Minghua Xiao; Anchuan Fan; Jifeng Xu

2014-01-01T23:59:59.000Z

94

Full $fp$-shell study of even-even $^{48-56}$Ti isotopes  

E-Print Network [OSTI]

The level schemes and transition rates {\\em B}({\\em E}2;$\\uparrow$) of eve-even $^{48-56}$Ti isotopes were studied by performing large-scale shell model calculations with FPD6 and GXPF1 effective interactions. Excellent agreement were obtained by comparing the first 2$^{+}$ level for all isotopes with the recently available experimental data, but studying the transition strengths {\\em B}({\\em E}2; 0$^+_{g.s.} \\to2^+_1$) for all Ti isotopes using constant proton-neutron effective charges prove the limitations of the present large-scale calculations to reproduce the experiment in detail.

F. A. Majeed; A. A. Auda

2006-02-02T23:59:59.000Z

95

High flux isotope reactor cold source preconceptual design study report  

SciTech Connect (OSTI)

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.

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

1995-12-01T23:59:59.000Z

96

Isotopic Analysis- Fluid At Indian Valley Hot Springs Geothermal Area  

Open Energy Info (EERE)

Isotopic Analysis- Fluid At Indian Valley Hot Springs Geothermal Area Isotopic Analysis- Fluid At Indian Valley Hot Springs Geothermal Area (1990) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Indian Valley Hot Springs Geothermal Area (1990) Exploration Activity Details Location Indian Valley Hot Springs Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1990 Usefulness not indicated DOE-funding Unknown Exploration Basis Determine the recharge of the area Notes Hydrogen and oxygen isotope data on waters of Coso thermal and nonthermal waters were studied. Hydrogen and oxygen isotopes do not uniquely define the recharge area for the Coso geothermal system but strongly suggest Sierran recharge with perhaps some local recharge. References

97

Stable-Isotope Studies Of Rocks And Secondary Minerals In A Vapor-Dominated  

Open Energy Info (EERE)

Stable-Isotope Studies Of Rocks And Secondary Minerals In A Vapor-Dominated Stable-Isotope Studies Of Rocks And Secondary Minerals In A Vapor-Dominated Hydrothermal System At The Geysers, Sonoma County, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Stable-Isotope Studies Of Rocks And Secondary Minerals In A Vapor-Dominated Hydrothermal System At The Geysers, Sonoma County, California Details Activities (5) Areas (1) Regions (0) Abstract: The Geysers, a vapor-dominated hydrothermal system, is developed in host rock of the Franciscan Formation, which contains veins of quartz and calcite whose Δ18O values record the temperatures and isotopic compositions of fluids prevailing during at least two different episodes of rock-fluid interaction. The first episode took place at about 200°C, during which marine silica and carbonate apparently interacted with ocean

98

Studies of the Di-iron(VI) Intermediate in Ferrate-Dependent Oxygen Evolution from Water  

E-Print Network [OSTI]

Information ABSTRACT: Molecular oxygen is produced from water via the following reaction of potassium ferrateStudies of the Di-iron(VI) Intermediate in Ferrate-Dependent Oxygen Evolution from Water Rupam consumption of natural abundance water. The derived 18 O KIEs provide insights concerning the identity

Roth, Justine P.

99

First decay study of the very neutron-rich isotope 93Br  

Science Journals Connector (OSTI)

The decay of the mass-separated, very neutron-rich isotope 93Br has been studied by ? spectroscopy. A level scheme of its daughter 93Kr has been constructed. Level energies, ?-ray branching ratios, and multipolarities suggest spins and parities which are in accord with a smooth systematics of the N=57 isotones for Z<~40, suggesting the N=56 subshell closure still to be effective in Kr isotopes. So far, there is no indication of a progressive onset of deformation in neutron-rich Kr isotopes.

G. Lhersonneau; A. Whr; B. Pfeiffer; K.-L. Kratz; the ISOLDE Collaboration

2001-02-20T23:59:59.000Z

100

Isotope-selective excitation of 41Ca isotope in Doppler-free two-photon continuous-wave excitation: a case study  

Science Journals Connector (OSTI)

Seven schemes are studied theoretically for Doppler-free two-photon excitation of rare 41Ca isotope using single-mode continuous-wave lasers. The ionization efficiencies...

Kumar, P V Kiran; Sankari, M; Acharyulu, G V S G; Suryanarayana, M V

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Experimental studies of 1 ton/day coal slurry feed type oxygen blown, entrained flow gasifier  

Science Journals Connector (OSTI)

Experimental Studies of a 1 Ton/Day coal slurry feed type oxygen blown, entrained flow gasifier have been performed with the slurry concentration and gasifier temperature at 65% and above 1,300...2.../coal feed r...

Young-Chan Choi; Tae-Jun Park; Jae-Ho Kim

2001-07-01T23:59:59.000Z

102

Global Climatic and Stable Isotopic Correlations During the Early Permian (Cisuralian)  

E-Print Network [OSTI]

and effects of global warming. This study presents new oxygen and carbon stable isotopic data (?18O and ?13C, VPDB) from carefully screened, early Permian brachiopod shells from the Ural Mountains. Using cathodoluminescence (CL) microscopy, 24 specimens were...

Noret, Jordan R.

2009-06-09T23:59:59.000Z

103

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

E-Print Network [OSTI]

of around 45 to 50°C. The study of uranium activity ratios for these Triassic formation waters allows us, uranium isotopes, oxygen isotopes, hydrogen isotopes, geothermometry, Trias, Paris Basin 1 hal-00563924,version1-7Feb2011 Author manuscript, published in "Chemical Geology 283, 3-4 (2011) 226-241" DOI : 10

Boyer, Edmond

104

Isotopic Analysis At San Juan Volcanic Field Area (Larson & Jr, 1986) |  

Open Energy Info (EERE)

Isotopic Analysis At San Juan Volcanic Field Area (Larson & Jr, 1986) Isotopic Analysis At San Juan Volcanic Field Area (Larson & Jr, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At San Juan Volcanic Field Area (Larson & Jr, 1986) Exploration Activity Details Location San Juan Volcanic Field Area Exploration Technique Isotopic Analysis- Rock Activity Date Usefulness not indicated DOE-funding Unknown Notes Oxygen isotopes. References Peter B. Larson, Hugh P. Taylor Jr (1986) An Oxygen Isotope Study Of Hydrothermal Alteration In The Lake City Caldera, San Juan Mountains, Colorado Retrieved from "http://en.openei.org/w/index.php?title=Isotopic_Analysis_At_San_Juan_Volcanic_Field_Area_(Larson_%26_Jr,_1986)&oldid=687474" Categories: Exploration Activities

105

Preliminary results from an isotope hydrology study of the Kilauea Volcano  

Open Energy Info (EERE)

results from an isotope hydrology study of the Kilauea Volcano results from an isotope hydrology study of the Kilauea Volcano area, Hawaii Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Preliminary results from an isotope hydrology study of the Kilauea Volcano area, Hawaii Abstract Deuterium (D) content of groundwater and precipitation, and tritium content of selected groundwater samples are used to infer flow paths for ground water in the Kilauea volcano area. The spatial distribution of calculated recharge elevations and residence times for groundwater samples tends to support the idea that Kilauea's rift zones comprise leaky boundaries within the regional groundwater flow system, partly isolating the groundwater in the area bounded by the rift zones and the Pacific Ocean. The south wesr

106

Carbon Isotopic Studies of Assimilated and Ecosystem Respired CO2 in a Southeastern Pine Forest  

SciTech Connect (OSTI)

Carbon dioxide is the major greenhouse gas responsible for global warming. Southeastern pine forests appear to be among the largest terrestrial sinks of carbon dioxide in the US. This collaborative study specifically addressed the isotopic signatures of the large fluxes of carbon taken up by photosynthesis and given off by respiration in this ecosystem. By measuring these isotopic signatures at the ecosystem level, we have provided data that will help to more accurately quantify the magnitude of carbon fluxes on the regional scale and how these fluxes vary in response to climatic parameters such as rainfall and air temperature. The focus of the MBL subcontract was to evaluate how processes operating at the physiological and ecosystem scales affects the resultant isotopic signature of plant waxes that are emitted as aerosols into the convective boundary layer. These wax aerosols provide a large-spatial scale integrative signal of isotopic discrimination of atmospheric carbon dioxide by terrestrial photosynthesis (Conte and Weber 2002). The ecosystem studies have greatly expanded of knowledge of wax biosynthetic controls on their isootpic signature The wax aerosol data products produced under this grant are directly applicable as input for global carbon modeling studies that use variations in the concentration and carbon isotopic composition of atmospheric carbon dioxide to quantify the magnitude and spatial and temporal patterns of carbon uptake on the global scale.

Maureen H. Conte

2008-04-10T23:59:59.000Z

107

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

SciTech Connect (OSTI)

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 elementsincluding alkaline earth elements, sodium, chromium, copper, manganese, lead, titanium, and zincduring 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 CUBwater interaction.

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

108

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

2005-08-01T23:59:59.000Z

109

Strontium isotopic study of subsurface brines from Illinois basin  

SciTech Connect (OSTI)

The abundance of the radiogenic isotope /sup 87/Sr in a subsurface brine can be used as a tracer of brine origin, evolution, and diagenetic effects. The authors have determined the /sup 87/Sr//sup 86/Sr ratios of over 60 oil-field waters from the Illinois basin, where brine origin is perplexing because of the absence of any significant evaporite strata. Initially, they analyzed brines from 15 petroleum-producing sandstone and carbonate units; waters from Ordovician, Silurian, Devonian, and Mississippian strata have /sup 87/Sr//sup 86/Sr ratios in the range 0.7079-0.7108. All but those from the Ste. Genevieve Limestone (middle Mississippian) are more radiogenic in /sup 87/Sr//sup 86/Sr than seawater values for this interval of geologic time. The detrital source of the more radiogenic /sup 87/Sr may be the New Albany Shale group, considered to be a major petroleum source rock in the basin. The /sup 87/Sr//sup 86/Sr ratios of Ste. Genevieve brines apparently evolved without a contribution from fluid-shale interaction.

hetherington, E.A.; Stueber, A.M.; Pushkar, P.

1986-05-01T23:59:59.000Z

110

Preliminary Study of Variations of Oxygen and Sulphur Isotope in Natural Sulphates  

Science Journals Connector (OSTI)

... variety of sulphates. O, Sulphate ion in sea water; A, sulphate ion in geothermal water, Wairakei, New Zealand; 0, sulphate ion in Lake Vanda, Antarctica; n ... in sulphate ion and the associated water. |S|, Sea waters2-4; A, geothermal water, Wairakei, New Zealand; O, saline water4; o, Lake Vanda, Antarctica. ...

T. A. RAFTER; Y. MIZUTANI

1967-12-09T23:59:59.000Z

111

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

E-Print Network [OSTI]

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

Bell, Alexis

112

Feasibility study of plutonium isotopic analysis of resin beads by nondestructive gamma-ray spectroscopy  

SciTech Connect (OSTI)

We have initiated a feasibility study on the use of nondestructive low-energy gamma-ray spectroscopy for plutonium isotopic analysis on resin beads. Seven resin bead samples were measured, with each sample containing an average of 9 ..mu..g of plutonium; the isotopic compositions of the samples varied over a wide range. The gamma-ray spectroscopy results, obtained from 4-h counting-time measurements, were compared with mass spectrometry results. The average ratios of gamma-ray spectroscopy to mass spectrometry were 1.014 +- 0.025 for /sup 238/Pu//sup 239/Pu, 0.996 +- 0.018 for /sup 240/Pu//sup 239/Pu, and 0.980 +- 0.038 for /sup 241/Pu//sup 239/Pu. The rapid, automated, and accurate nondestructive isotopic analysis of resin beads may be very useful to process technicians and International Atomic Energy Agency inspectors. 3 refs., 1 fig., 3 tabs.

Li, T.K.

1985-01-01T23:59:59.000Z

113

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

SciTech Connect (OSTI)

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.

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

1994-08-01T23:59:59.000Z

114

Environmental isotope investigation of groundwater flow in the Honey Lake Basin, California and Nevada  

SciTech Connect (OSTI)

The hydrology of Honey Lake Basin was studied using environmental isotope measurements of approximately 130 water samples collected during 1995 and 1996. The principal analytical methods included hydrogen, oxygen and carbon stable isotope ratio measurements, radiocarbon and tritium dating, and measurements of dissolved noble gas abundances.

Rose, T.P.; Davisson, M.L.; Hudson, G.B.; Varian, A.R.

1997-07-01T23:59:59.000Z

115

Oxygen isotope ratio measurements in CO2 by means of a continuous-wave quantum cascade laser at 4.3 ?m  

Science Journals Connector (OSTI)

A mid-infrared laser spectrometer was developed for simultaneous high-precision 18O/16O and 17O/16O isotope ratio measurements in carbon...

Castrillo, Antonio; Casa, Giovanni; Gianfrani, Livio

2007-01-01T23:59:59.000Z

116

Heat conduction of single-walled carbon nanotube isotope-superlattice structures: A molecular dynamics study  

E-Print Network [OSTI]

-folding effect to thermal boundary resistance of lattice interface. The crossover mechanism is explained-dimensional materials. In our previous molecular dynamics study, isotope-effects on the thermal conduction were of heat conduction of SWNTs subjected to nanoscale intrinsic thermal resistances. Here, in order to reduce

Maruyama, Shigeo

117

Calorimetric studies of oxygen adsorption on silver powder and of CO and CO/sub 2/ interactions with preadsorbed oxygen on silver  

SciTech Connect (OSTI)

The initial rapid oxygen adsorption on powdered silver ethylene oxidation catalyst had a heat of adsorption that decreased from 70 to 40 kcal/mole as the adsorbed amount increased from 2 to 20 jmole/sq m. The rapid oxygen adsorption covered about one-fourth of the silver surface. Carbon monoxide adsorbed on the oxygen-covered silver with an initial heat of adsorption of 90 kcal/mole which decreased after 0.6 jmole/sq m CO were adsorbed and was approx. 70 kcal/mole at 2 jmole/sq m CO. Carbon dioxide adsorbed on the oxygen-covered surface with 38 kcal/mole heat of adsorption that was independent of coverage. The adsorption study provided evidence for the formation of adsorbed carbonate (CO/sub 3/) surface complexes.

Vass, M.I.; Budrugeac, P.

1980-07-01T23:59:59.000Z

118

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

SciTech Connect (OSTI)

We use density functional theory to study the difference in the structure, stability and catalytic reactivity between ultrathin, 0.5- 1.0 nm diameter, platinum nanotubes and nanowires. Model nanowires were formed by inserting an inner chain of platinum atoms in small diameter nanotubes. In this way more stable, nonhollow structures were formed. The difference in the electronic structure of platinum nanotubes and nanowires was examined by inspecting the density of surface states and band structure. Furthermore, reactivity towards the oxygen reduction reaction of platinum nanowires was addressed by studying the change in the chemisorption energies of oxygen and hydroxyl groups, induced by inserting the inner chain of platinum atoms into the hollow nanotubes. Both ultrathin platinum nanotubes and nanowires show distinct properties compared to bulk platinum. Nanotubes with diameters larger than 1 nm show promise for use as oxygen reduction catalysts.

Matanovic, Ivana; Kent, Paul; Garzon, Fernando; Henson, Neil J.

2012-10-10T23:59:59.000Z

119

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

SciTech Connect (OSTI)

We used density functional theory to study the difference in the structure, stability and catalytic reactivity between ultrathin, 0.51.0 nm diameter, platinum nanotubes and nanowires. Model nanowires were formed by inserting an inner chain of platinum atoms in small diameter nanotubes. In this way more stable, non-hollow structures were formed. The difference in the electronic structure of platinum nanotubes and nanowires was examined by inspecting the density of surface states and band structure. Furthermore, reactivity toward the oxygen reduction reaction of platinum nanowires was assessed by studying the change in the chemisorption energies of oxygen, hydroxyl, and hydroperoxyl groups, induced by converting the nanotube models to nanowires. Both ultrathin platinum nanotubes and nanowires show distinct properties compared to bulk platinum. Single-wall nanotubes and platinum nanowires with diameters larger than 1 nm show promise for use as oxygen reduction catalysts.

Matanovic, Ivana; Kent, Paul; Garzon, Fernando; Henson, Neil J.

2013-03-14T23:59:59.000Z

120

Isotopic Analysis- Rock At Long Valley Caldera Area (Smith & Suemnicht,  

Open Energy Info (EERE)

Isotopic Analysis- Rock At Long Valley Caldera Area (Smith & Suemnicht, Isotopic Analysis- Rock At Long Valley Caldera Area (Smith & Suemnicht, 1991) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At Long Valley Caldera Area (Smith & Suemnicht, 1991) Exploration Activity Details Location Long Valley Caldera Area Exploration Technique Isotopic Analysis- Rock Activity Date Usefulness useful DOE-funding Unknown Notes This oxygen isotope and fluid inclusion study has allowed us to determine the pathways of fluid circulation, set limits on the thermal regime, and link the source of the heat to prolonged volcanic activity. At shallow depths in the caldera References Brian M. Smith, Gene A. Suemnicht (1991) Oxygen Isotope Evidence For Past And Present Hydrothermal Regimes Of Long Valley Caldera, California

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Isotopic Analysis- Fluid At Coso Geothermal Area (1990) | Open Energy  

Open Energy Info (EERE)

Analysis- Fluid At Coso Geothermal Area (1990) Analysis- Fluid At Coso Geothermal Area (1990) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Coso Geothermal Area (1990) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1990 Usefulness not indicated DOE-funding Unknown Exploration Basis Determine the recharge of the area Notes Hydrogen and oxygen isotope data on waters of Coso thermal and nonthermal waters were studied. Hydrogen and oxygen isotopes do not uniquely define the recharge area for the Coso geothermal system but strongly suggest Sierran recharge with perhaps some local recharge. References Whelan, J. A. (1 September 1990) Water geochemistry study of Indian Wells Valley, Inyo and Kern Counties, California. Supplement.

122

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

E-Print Network [OSTI]

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

Mcdonough, William F.

123

Time-Resolved EPR Study of Singlet Oxygen in the Gas Phase Marco Ruzzi,  

E-Print Network [OSTI]

Time-Resolved EPR Study of Singlet Oxygen in the Gas Phase Marco Ruzzi, Elena Sartori, Alberto States ABSTRACT: X-band EPR spectra of singlet O2(1 g) and triplet O2(3 g - ) were observed in the gas, and perfluoronaphthalene in the gas phase. The EPR spectrum of O2(1 g) was also observed under microwave discharge

Turro, Nicholas J.

124

EIS Studies of Porous Oxygen Electrodes with Discrete II. Transmission Line Modeling  

E-Print Network [OSTI]

EIS Studies of Porous Oxygen Electrodes with Discrete Particles II. Transmission Line Modeling Chad conclusions. We describe a new model based on an array of parallel, nonuniform transmission lines to be the first porous electrode transmission line model that incorporates such physically realistic features

125

An isotopic study of the Coso, California, geothermal area | Open Energy  

Open Energy Info (EERE)

study of the Coso, California, geothermal area study of the Coso, California, geothermal area Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: An isotopic study of the Coso, California, geothermal area Details Activities (1) Areas (1) Regions (0) Abstract: Thirty-nine water samples were collected from the Coso geothermal system and vicinity and were analyzed for major chemical constituents and deltaD and delta^18/O. Non-thermal ground waters from the Coso Range were found to be isotopically heavier than non-thermal ground waters from the Sierra Nevada to the west. The deltaD value for the deep thermal water at Coso is similar to that of the Sierra water, suggesting that the major recharge for the hydrothermal system comes from the Sierra Nevada rather than from local precipitation on the Coso Range. The delta^18/O values of

126

Isotope Evidence for Ozone Formation on Surfaces  

Science Journals Connector (OSTI)

Remarkably, the gas-phase recombination or association reaction of ozone has an unusually large (?10%) isotope effect and shows almost equal enrichments of the ozone molecules containing two different oxygen isotopes. ... For a better understanding of the pressure and temperature dependence of ozone isotopic composition in oxygen discharges, we developed a relatively simple isotope kinetic model that accounts for the processes of (i) heterogeneous ozone formation at the reactor walls, (ii) isotope exchange of oxygen atoms with O2 molecules, and (iii) ozone formation in the gas phase. ...

Christof Janssen; Bla Tuzson

2010-05-06T23:59:59.000Z

127

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

2005-02-01T23:59:59.000Z

128

Stable isotope studies. Final report, March 1, 1972--February 29, 1992  

SciTech Connect (OSTI)

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.

Ishida, T.

1992-10-01T23:59:59.000Z

129

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

SciTech Connect (OSTI)

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 Li4+xTi5O12/LiPON/LixV2O5 cell and examine in situ the chemistry of Li-O2 reaction products on LixV2O5 as a function of applied voltage under ultra high vacuum (UHV) and near ambient-pressure of oxygen using X-ray photoelectron spectroscopy (APXPS). Oxygen reduction and evolution reactions take place on the surface of the mixed electronic and Li+ ionic conductor, LixV2O5, which eliminate parasitic reactions between oxygen reduction/evolution reaction intermediates and aprotic electrolytes used in Li-O2 batteries reported to date. Under UHV, reversible lithium intercalation and de-intercalation from LixV2O5 was noted, where the changes in the vanadium valence state revealed from XPS in this study were comparable to that reported previously from Li/LixV2O5 thin film batteries. In presence of oxygen near ambient pressure, the LixV2O5 surface was covered gradually by the reaction product of oxygen reduction, namely lithium peroxide (Li2O2) (approximately 1-2 unit cells) upon discharge. Interestingly, the LixV2O5 surface became re-exposed upon charging, and the oxidation of Li2O2 began at much lower overpotentials (~240 mV) than the charge overpotentials of Li-O2 cells (~1000 mV) with aprotic electrolytes, which can be attributed to subnanometer-thick Li2O2 with surfaces free of contaminants such as carbonate species. Our study provides first evidence of reversible lithium peroxide formation and decomposition in situ on an oxide surface using a solid-state cell, and new insights into the reaction mechanism of Li-O2 chemistry.

Lu, Yi-chun [Massachusetts Institute of Technology (MIT); Crumlin, Ethan [Massachusetts Institute of Technology (MIT); Veith, Gabriel M [ORNL; Harding, Jonathon [Massachusetts Institute of Technology (MIT); Dudney, Nancy J [ORNL; Liu, Zhi [Lawrence Berkeley National Laboratory (LBNL); Shao-Horn, Yang [Massachusetts Institute of Technology (MIT)

2012-01-01T23:59:59.000Z

130

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

E-Print Network [OSTI]

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.

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. Flp; G. Gervino; A. Guglielmetti; C. Gustavino; Gy. Gyrky; 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. Szcs; F. Terrasi; H. P. Trautvetter; D. Trezzi

2012-10-01T23:59:59.000Z

131

California GAMA Special Study: An isotopic and dissolved gas investigation of nitrate source and transport to a public supply well in California's Central Valley  

SciTech Connect (OSTI)

This study investigates nitrate contamination of a deep municipal drinking water production well in Ripon, CA to demonstrate the utility of natural groundwater tracers in constraining the sources and transport of nitrate to deep aquifers in the Central Valley. The goal of the study was to investigate the origin (source) of elevated nitrate and the potential for the deep aquifer to attenuate anthropogenic nitrate. The site is ideal for such an investigation. The production well is screened from 165-325 feet below ground surface and a number of nearby shallow and deep monitoring wells were available for sampling. Furthermore, potential sources of nitrate contamination to the well had been identified, including a fertilizer supply plant located approximately 1000 feet to the east and local almond groves. A variety of natural isotopic and dissolved gas tracers including {sup 3}H-{sup 3}He groundwater age and the isotopic composition of nitrate are applied to identify nitrate sources and to characterize nitrate transport. An advanced method for sampling production wells is employed to help identify contaminant contributions from specific screen intervals. Nitrate transport: Groundwater nitrate at this field site is not being actively denitrified. Groundwater parameters indicate oxic conditions, the dissolved gas data shows no evidence for excess nitrogen as the result of denitrification, and nitrate-N and -O isotope compositions do not display patterns typical of denitrification. Contaminant nitrate source: The ambient nitrate concentration in shallow groundwater at the Ripon site ({approx}12 mg/L as nitrate) is typical of shallow groundwaters affected by recharge from agricultural and urban areas. Nitrate concentrations in Ripon City Well 12 (50-58 mg/L as nitrate) are significantly higher than these ambient concentrations, indicating an additional source of anthropogenic nitrate is affecting groundwater in the capture zone of this municipal drinking water well. This study provides two new pieces of evidence that the Ripon Farm Services Plant is the source of elevated nitrate in Ripon City Well 12. (1) Chemical mass balance calculations using nitrate concentration, nitrate isotopic composition, and initial tritium activity all indicate that that the source water for elevated nitrate to Ripon City Well 12 is a very small component of the water produced by City Well 12 and thus must have extremely high nitrate concentration. The high source water nitrate concentration ({approx}1500 mg/L as nitrate) required by these mass balance calculations precludes common sources of nitrate such as irrigated agriculture, dairy wastewater, and septic discharge. Shallow groundwater under the Ripon Farm Services RFS plant does contain extremely high concentrations of nitrate (>1700 mg/L as nitrate). (2) Nitrogen and oxygen isotope compositions of nitrate indicate that the additional anthropogenic nitrate source to Ripon City Well 12 is significantly enriched in {delta}{sup 18}O-NO{sub 3}, an isotopic signature consistent with synthetic nitrate fertilizer, and not with human or animal wastewater discharge (i.e. dairy operations, septic system discharge, or municipal wastewater discharge), or with organic fertilizer. Monitoring wells on and near the RFS plant also have high {delta}{sup 18}O-NO{sub 3}, and the plant has handled and stored synthetic nitrate fertilizer that will have this isotopic signature. The results described here highlight the complexity of attributing nitrate found in long screened, high capacity wells to specific sources. In this case, the presence of a very high concentration source near the well site combined with sampling using multiple isotopic tracer techniques and specialized depth-specific techniques allowed fingerprinting of the source in the mixed-age samples drawn from the production well.

Singleton, M J; Moran, J E; Esser, B K; Roberts, S K; Hillegonds, D J

2010-04-14T23:59:59.000Z

132

Automated data extraction from in situ protein stable isotope...  

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

data extraction from in situ protein stable isotope probing studies. Automated data extraction from in situ protein stable isotope probing studies. Abstract: Protein stable isotope...

133

Perchlorate Isotope Forensics  

Science Journals Connector (OSTI)

In this study, comprehensive stable isotope analyses (37Cl/35Cl and 18O/17O/16O) of perchlorate from known synthetic and natural sources reveal systematic differences in isotopic characteristics that are related to the formation mechanisms. ... ?37Cl and ?18O are measures of mass-dependent fractionation of Cl and O isotopes by normal physical, chemical, or biological processes. ...

John Karl Bhlke; Neil C. Sturchio; Baohua Gu; Juske Horita; Gilbert M. Brown; W. Andrew Jackson; Jacimaria Batista; Paul B. Hatzinger

2005-11-04T23:59:59.000Z

134

Negative Oxygen Isotope Effect on the Static Spin Stripe Order in Superconducting La2?xBaxCuO4(x=1/8) Observed by Muon-Spin Rotation  

Science Journals Connector (OSTI)

Large negative oxygen-isotope (O16?and?O18) effects (OIEs) on the static spin-stripe-ordering temperature Tso and the magnetic volume fraction Vm were observed in La2?xBaxCuO4(x=1/8) by means of muon-spin-rotation experiments. The corresponding OIE exponents were found to be ?Tso=?0.57(6) and ?Vm=?0.71(9), which are sign reversed to ?Tc=0.46(6) measured for the superconducting transition temperature Tc. This indicates that the electron-lattice interaction is involved in the stripe formation and plays an important role in the competition between bulk superconductivity and static stripe order in the cuprates.

Z. Guguchia; R. Khasanov; M. Bendele; E. Pomjakushina; K. Conder; A. Shengelaya; H. Keller

2014-07-30T23:59:59.000Z

135

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

136

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

SciTech Connect (OSTI)

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.

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

2010-11-30T23:59:59.000Z

137

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

E-Print Network [OSTI]

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 ...

Lu, Yi-chun

138

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

E-Print Network [OSTI]

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 ...

Crumlin, Ethan J

2012-01-01T23:59:59.000Z

139

A neutronic feasibility study for LEU conversion of the high flux isotope reactor (HFIR).  

SciTech Connect (OSTI)

A neutronic feasibility study was performed to determine the uranium densities that would be required to convert the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) from HEU (93%) to LEU (<20%)fuel. The LEU core that was studied is the same as the current HEU core, except for potential changes in the design of the fuel plates. The study concludes that conversion of HFIR from HEU to LEU fuel would require an advanced fuel with a uranium density of 6-7 gU/cm{sup 3} in the inner fuel element and 9-10 gU/cm{sup 3} in the outer fuel element to match the cycle length of the HEU core. LEU fuel with uranium density up to 4.8 gU/cm{sup 3} is currently qualified for research reactor use. Modifications in fuel grading and burnable poison distribution are needed to produce an acceptable power distribution.

Mo, S. C.

1998-01-14T23:59:59.000Z

140

Density functional theory study of oxygen and water adsorption on SrTiO3(001)  

E-Print Network [OSTI]

effortlessly leading to the formation of a pair of hydroxyl groups. For the titanium dioxide termina- tionDensity functional theory study of oxygen and water adsorption on SrTiO3(001) D I S S E R TAT I O N and they are computationally feasible. For the oxygen and water adsorption the binding energy is controlled by long-range sur

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

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

SciTech Connect (OSTI)

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

Dobson, Patrick

2013-02-11T23:59:59.000Z

142

An experimental study of magnesium-isotope fractionation in chlorophyll-a photosynthesis  

E-Print Network [OSTI]

phosphorylation is a magnesium nuclear spin controlledMagnetic isotope effect of magnesium in phosphoglycerateexchange activities in magnesium chelatase subunits of

Black, J R; Yin, Q Z; Casey, W H

2006-01-01T23:59:59.000Z

143

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

E-Print Network [OSTI]

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

Mcdonough, William F.

144

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

145

Project EARTH-13-AH1: Isotopic studies of continental weathering -the transport of germanium in soils and plants  

E-Print Network [OSTI]

Project EARTH-13-AH1: Isotopic studies of continental weathering - the transport of germanium silicate weathering is important if we are to understand the carbon cycle 1,2 . The similarity of Ge and Si for weathering intensity3,7-9 . However, factors driving Ge behaviour in soil remain largely unknown although

Henderson, Gideon

146

Doped Graphene as a Material for Oxygen Reduction Reaction in Hydrogen Fuel Cells: A Computational Study  

E-Print Network [OSTI]

Doped Graphene as a Material for Oxygen Reduction Reaction in Hydrogen Fuel Cells: A Computational be used to make an efficient and relatively inexpensive graphene-based material for hydrogen fuel cells fuel cells for oxygen reduction at the cathode. In an attempt to find a cheap yet efficient catalyst

Krasheninnikov, Arkady V.

147

High-Velocity Oxygen Fuel Thermal Spray of Fe-Based Amorphous Alloy: a Numerical and Experimental Study  

E-Print Network [OSTI]

High-Velocity Oxygen Fuel Thermal Spray of Fe-Basedusing a high velocity oxygen fuel (HVOF) spray processstructure. [12] High velocity oxygen fuel (HVOF) thermal

Ajdelsztajn, L.; Dannenberg, J.; Lopez, J.; Yang, N.; Farmer, J.; Lavernia, E. J.

2009-01-01T23:59:59.000Z

148

Nuclear shape coexistence: A study of the even-even Hg isotopes using the interacting boson model with configuration mixing  

E-Print Network [OSTI]

Background: The Po, Pb, Hg, and Pt region is known for the presence of coexisting structures that correspond to different particle-hole configurations in the Shell Model language or equivalently to nuclear shapes with different deformation. Purpose: We intend to study the configuration mixing phenomenon in the Hg isotopes and to understand how different observables are influenced by it. Method: We study in detail a long chain of mercury isotopes, $^{172-200}$Hg, using the interacting boson model with configuration mixing. The parameters of the Hamiltonians are fixed through a least square fit to the known energies and absolute B(E2) transition rates of states up to $3$ MeV. Results: We obtained the IBM-CM Hamiltonians and we calculate excitation energies, B(E2)'s, quadrupole shape invariants, wave functions, isotopic shifts, and mean field energy surfaces. Conclusions: We obtain a fairly good agreement with the experimental data for all the studied observables and we conclude that the Hamiltonian and the states we obtain constitute a good approximation to the Hg isotopes.

J. E. Garcia-Ramos; K. Heyde

2013-12-17T23:59:59.000Z

149

Study of hydrogen isotopes super permeation through vanadium membrane on 'Prometheus' setup  

SciTech Connect (OSTI)

To develop the membrane pumping technology by means of superpermeable membranes at RFNC-VNIIEF in the 'Prometheus' setup, the experiments on superpermeation of hydrogen isotopes through metal membranes were carried out. The experimental results on superpermeation of thermal atoms of hydrogen isotopes including tritium through a cylindrical vanadium membrane are presented. The possibility of effective pumping, compression and recuperation of hydrogen isotopes by means of superpermeable membrane was demonstrated. The evaluation of membrane pumping rates and asymmetry degree of pure vanadium membrane was given. The work was performed under the ISTC-2854 project. (authors)

Musyaev, R. K.; Yukhimchuk, A. A.; Lebedev, B. S. [Russian Federal Nuclear Center-All-Russian Research Inst. of Experimental Physics RFNC-VNIIEF, 607188, Sarov, Nizhny Novgorod Region (Russian Federation); Busnyuk, A. O.; Notkin, M. E.; Samartsev, A. A.; Livshits, A. I. [St. Peterburg State Univ. of Telecommunications SUT, St. Peterburg (Russian Federation)

2008-07-15T23:59:59.000Z

150

Geochemical study of boron isotopes in the process of loess weathering  

Science Journals Connector (OSTI)

In this paper the boron contents and boron isotopic composition of acid-soluble phases in loess and paleosol samples are determined for the first time. The boron contents of acid-soluble phases in the Luochuan...

Zhiqi Zhao; Congqiang Liu; Yingkai Xiao

2003-02-01T23:59:59.000Z

151

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

E-Print Network [OSTI]

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...

Downer, Roswell Curtis

2012-06-07T23:59:59.000Z

152

Boron isotopic variations in hydrous rhyolitic melts: a case study from Long Valley, California  

Science Journals Connector (OSTI)

In this paper, we present boron isotope analyses of variably degassed rhyolitic glasses from Long Valley, California. The following results indicate that...2O-rich (~3wt%) melt inclusions from late erupted Bisho...

A. K. Schmitt; J. I. Simon

2004-01-01T23:59:59.000Z

153

New experimental study of low-energy (p,gamma) resonances in magnesium isotopes  

E-Print Network [OSTI]

Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H shell burning. In particular, the strengths of low-energy resonances with E < 200 keV in 25Mg(p,gamma)26Al determine the production of 26Al and a precise knowledge of these nuclear data is highly desirable. Absolute measurements at such low-energies are often very difficult and hampered by gamma-ray background as well as changing target stoichiometry during the measurements. The latter problem can be partly avoided using higher energy resonances of the same reaction as a normalization reference. Hence the parameters of suitable resonances have to be studied with adequate precision. In the present work we report on new measurements of the resonance strengths omega_gamma of the E = 214, 304, and 326 keV resonances in the reactions 24Mg(p,gamma)25Al, 25Mg(p,gamma)26Al, and 26Mg(p,gamma)27Al, respectively. These studies were performed at the LUNA facility in the Gran Sasso underground laboratory using multiple experimental techniques and provided results with a higher accuracy than previously achieved.

B. Limata; F. Strieder; A. Formicola; G. Imbriani; M. Junker; H. W. Becker; D. Bemmerer; A. Best; R. Bonetti; C. Broggini; A. Caciolli; P. Corvisiero; H. Costantini; A. DiLeva; Z. Elekes; Zs. Flp; G. Gervino; A. Guglielmetti; C. Gustavino; Gy. Gyrky; A. Lemut; M. Marta; C. Mazzocchi; R. Menegazzo; P. Prati; V. Roca; C. Rolfs; C. Rossi Alvarez; C. Salvo; E. Somorjai; O. Straniero; F. Terrasi; H. -P. Trautvetter

2010-06-28T23:59:59.000Z

154

Study on modification of Cu-based oxygen carrier for chemical looping combustion  

Science Journals Connector (OSTI)

Chemical looping combustion (CLC) is a promising technology for...2O4...spinel, formed after the first few redox cycles, which is responsible for promoting the thermal stability of the oxygen carriers. SEM result...

Hou-yin Zhao; Yan Cao; William Orndorff

2013-09-01T23:59:59.000Z

155

Determination of Hydrocarbons Types and Oxygenates in Motor Gasoline: A Comparative Study by Different Analytical Techniques  

Science Journals Connector (OSTI)

Various standard and published methods based on chromatographic and spectroscopic techniques are routinely used for hydrocarbon types (aromatics, olefins, oxygenates, etc.) in gasoline range fuel products for the assessment of product quality monitoring (...

V. Bansal; G. J. Krishna; A. P. Singh; A. K. Gupta; A. S. Sarpal

2007-12-04T23:59:59.000Z

156

Experimental study of active magnetic bearing on a 150M3 turbo oxygen gas expander  

Science Journals Connector (OSTI)

This paper is concerned with the investigation, experiment and design analyses on the application of active magnetic bearings for a 150M3 turbo oxygen gas expander having 1.16 kg weight and 30...

Wang Xiping Ph. D; Zhang Zhiming; Yu Liang

1998-12-01T23:59:59.000Z

157

Isotopic tracer studies of oxygen transport through SiO2 films at 1000?C using secondary ion mass spectrometry  

Science Journals Connector (OSTI)

Dry oxides (?8 ppm H2O) grown on Si(100) at 1000?C at 1 atm using purified 1 6O2 and purified 1 8O2 were analyzed using secondary ion mass spectrometry.1 8O is observed at the interface in the bulk of the 1 6O oxide and at the surface in agreement with other recent reports. Our results show little lattice diffusion in agreement with Mikkelsens work [Appl. Phys. Lett. 4 5 1187 (1984)]. A previous report [J. Electrochem. Soc. 1 3 1 1944 (1984)] of appreciable lattice diffusion is due to higher water content.

C. J. Han; C. R. Helms

1986-01-01T23:59:59.000Z

158

Atomic Spectroscopy and Separated Isotopes  

Science Journals Connector (OSTI)

The advantages in the use of separated isotopes in atomic spectroscopy for the determination of nuclear momentsI ? Q and for studies of the isotope-shift phenomena are discussed. Illustrations of spectra are given for mercury uranium and samarium. In addition a summary is given of twenty-two so-called problem nuclei i.e. those naturally occurring isotopes for which the nuclear moments are completely uncertain. Concluding remarks are made on such problems as the evaluation of the absolute magnitude of isotope shifts the role of forbidden transitions in isotope spectra and the potential future value of spectro-isotopic assay techniques.

J. R. McNally Jr.

1952-01-01T23:59:59.000Z

159

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

SciTech Connect (OSTI)

The structure, stability, and catalytic activity of a number of single- and double-wall platinum (n,m) nanotubes ranging in diameter from 0.3 to 2.0 nm were studied using plane-wave based density functional theory in the gas phase and water environment. The change in the catalytic activity toward the oxygen reduction reaction (ORR) with the size and chirality of the nanotube was studied by calculating equilibrium adsorption potentials for ORR intermediates and by constructing free energy diagrams in the ORR dissociative mechanism network. In addition, the stability of the platinum nanotubes is investigated in terms of electrochemical dissolution potentials and by determining the most stable state of the material as a function of pH and potential, as represented in Pourbaix diagrams. Our results show that the catalytic activity and the stability toward electrochemical dissolution depend greatly on the diameter and chirality of the nanotube. On the basis of the estimated overpotentials for ORR, we conclude that smaller, approximately 0.5 nm in diameter single-wall platinum nanotubes consistently show a huge, up to 400 mV larger overpotential than platinum, indicating very poor catalytic activity toward ORR. This is the result of substantial structural changes induced by the adsorption of any chemical species on these tubes. Single-wall n = m platinum nanotubes with a diameter larger than 1 nm have smaller ORR overpotentials than bulk platinum for up to 180 mV and thus show improved catalytic activity relative to bulk. We also predict that these nanotubes can endure the highest cell potentials but dissolution potentials are still for 110 mV lower than for the bulk, indicating a possible corrosion problem.

Matanovic, Ivana; Kent, Paul; Garzon, Fernando; Henson, Neil J.

2012-07-13T23:59:59.000Z

160

Dynamical Host/Guest Interactions in Zeolites:? Framework Isotope Effects on Proton Transfer Studied by Car?Parrinello Molecular Dynamics  

Science Journals Connector (OSTI)

Dynamical Host/Guest Interactions in Zeolites:? Framework Isotope Effects on Proton Transfer Studied by Car?Parrinello Molecular Dynamics ... While in liquids the proper relaxation mechanisms can be described in terms of the orientational correlation functions of solvent molecules,8 in solids and in zeolites in particular, velocity or dipole autocorrelation functions (or their Fourier Transform giving the power or IR spectra) are good candidates to describe this phenomenon. ... A single band in the stretching region indicates the absence of water molecules. ...

Ettore Fois; Aldo Gamba

1999-03-02T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

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

E-Print Network [OSTI]

isotopes of Kr II. TABLE I. Compilation of the Natural Abundances and the Masses of the Krypton Isotopes A N 78 42 80 44 82 46 83 47 84 48 86 50 Abundance(%) 0. 35 2. 25 11. 6 11. 5 57. 0 17, 3 Mass(amu) 77. 920397 79. 916375 81. 913483... does not need to be considered in the error analysis since it leads only to a broadening but not to s. shift of the measured signals. The voltage uncer- tainties are limited by the voltage divider. For 6V/V=10, 6(AV)/ZV=IO 6mr ? 6rns=10 amu and p=0...

Li, Yingfeng

2012-06-07T23:59:59.000Z

162

Theoretical study of odd-mass Fr isotopes using the collective clusterization approach of the dynamical cluster-decay model  

Science Journals Connector (OSTI)

The reaction dynamics of various odd-mass Fr isotopes is studied over a wide range of incident energies, spread across the Coulomb barrier. The specific reactions analyzed are 18O+197Au and 19F+192,194,196,198,200Pt, forming odd-mass 211?219Fr* compound systems where some data are available for three of these isotopes: 213,215,217Fr*. Based on the dynamical cluster-decay model (DCM), we have extended our calculations of the evaporation residue (ER) cross sections to the mainly fissioning 215Fr*, using the systematics of 213,217Fr* isotopes where the available ER cross sections (as well as fusion-fission cross sections) were studied earlier within the DCM. In order to obtain a clear picture of the dynamics involved, including entrance channel effects, the variations of fragmentation potential, preformation factor, and decay barrier height are analyzed. The relevance of barrier modification effects is also explored in the decay of 213,215,217Fr* nuclei. In addition, fusion-fission (ff) cross sections are extended to 213,217Fr* systems where some more data has recently become available. Also, the fission fragment anisotropies (so far measured and studied for 215Fr* alone) are estimated for 213,217Fr* using DCM for the use of nonsticking moment of inertia, and relevant comparison with the sticking moment-of-inertia approach is analyzed. Furthermore, the shell closure effects of the decay fragments are investigated for odd-mass 211?219Fr* isotopes.

Gudveen Sawhney; Gurvinder Kaur; Manoj K. Sharma; Raj K. Gupta

2013-09-09T23:59:59.000Z

163

Low-lying dipole excitations in vibrational nuclei: The Cd isotopic chain studied in photon scattering experiments  

SciTech Connect (OSTI)

High-resolution nuclear resonance fluorescence experiments (NRF) were performed on {sup 110,111,112,114,116}Cd at the bremsstrahlung facility of the 4.3-MV Dynamitron accelerator in Stuttgart to study the low-lying dipole strength distributions in these vibrational nuclei. Numerous excited states, most of them previously unknown, were observed in the excitation energy range up to 4 MeV. Detailed spectroscopic information has been obtained on excitation energies, spins, decay widths, decay branchings, and transition probabilities. For states in the even-even isotopes {sup 110,112,114,116}Cd, parities could be assigned from linear polarization measurements. Together with our previous results for {sup 108,112,113,114}Cd from NRF studies without polarization measurements, systematics was established for the dipole strength distributions of the stable nuclei within the Cd isotopic chain. The results are discussed with respect to the systematics of E1 two-phonon excitations and mixed-symmetry states in even-even nuclei near the Z=50 shell closure and the fragmentation of these excitation modes in the odd-mass Cd isotopes.

Kohstall, C.; Belic, D.; Kneissl, U.; Nord, A.; Pitz, H.H.; Scheck, M.; Stedile, F. [Institut fuer Strahlenphysik, Universitaet Stuttgart, D-70569 Stuttgart (Germany); Brentano, P. von; Fransen, C.; Gade, A.; Herzberg, R.-D.; Jolie, J.; Linnemann, A.; Pietralla, N.; Werner, V. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Cologne (Germany); Yates, S.W. [Departments of Chemistry and Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)

2005-09-01T23:59:59.000Z

164

DNA combing on low-pressure oxygen plasma modified polysilsesquioxane substrates for single-molecule studies  

E-Print Network [OSTI]

DNA combing on low-pressure oxygen plasma modified polysilsesquioxane substrates for single-molecule.1063/1.4878635 A highly parallel microfluidic droplet method enabling single-molecule counting for digital enzyme-treatment and molecular diagnosis Biomicrofluidics 6, 034119 (2012); 10.1063/1.4748358 Single molecule analysis

165

PROPOSITION DE SUJET DE THESE Fundamental study of oxygen exchange and diffusion in cathode  

E-Print Network [OSTI]

materials for fuel cells G. Dezanneau, in collaboration with G. Geneste (CEA) Fuel cells are electrochemical devices that allow the conversion of hydrogen into electricity and heat. One of the main limitations factor for the cell efficiency. This efficiency is basically driven by the oxygen exchange and diffusion

Bezerianos, Anastasia

166

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

E-Print Network [OSTI]

, but very low concentrations of U (Th (- alization (Watkinson and Dunning 1979) and zone-refining processes (Brügmann et al. 1989). Based on recent high concentrations of U and Th compared to mantle rocks, which makes Pb isotope compositions

167

The lost years of green turtles: using stable isotopes to study cryptic lifestages  

Science Journals Connector (OSTI)

...50-year mystery in the biology of marine turtles posed by Archie Carr...ecology and trophic structure in marine and terrestrial ecosystems...trophic position, and, in marine environments, carbon isotopes...although it is susceptible to wear, retains a history of diet...

2007-01-01T23:59:59.000Z

168

Isotopes in Environmental and Health Studies Vol. 41, No. 4, December 2005, 293302  

E-Print Network [OSTI]

deployable quantum cascade laser-based sensor is described, along with line selection strategy for 13/12CO2 sensors; IR spectrometry; Natural isotope ratios; Volcanoes 1. Introduction Tunable laser absorption for the detection of low gas concentra- tion levels by improving the signal-to-noise ratio of the spectrometer

169

Intramolecular Isotope Effects for the Study of Reactions with MassTransfer Limitations  

E-Print Network [OSTI]

Page Figure 1 The origin of the kinetic isotope effect.............................................. 15 Figure 2 The solvent cage complexes of substrate and radical in intermolecular case............................................................................... 16 Figure 3 The solvent cage complex of substrate and radical in the intramolecular case ............................................................................ 17 Figure 4 Hydrogens to be used to calculate intermolecular KIE...

Wagner, Joshua G.

2010-01-16T23:59:59.000Z

170

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

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

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

Dobson, Patrick

171

?-decay studies of the francium isotopes 198Fr and 199Fr  

Science Journals Connector (OSTI)

Very neutron deficient francium isotopes have been produced in fusion evaporation reactions using 60Ni ions on 141Pr targets. The gas-filled recoil separator RITU was employed to collect the fusion products and to separate them from the scattered beam. The activities were implanted into a position sensitive silicon detector after passing through a gas-counter system. The isotopes were identified using spatial and time correlations between the implants and the decays. Two ?-particle activities, with E?=7613(15) keV and T1/2 = (15?5+12) ms and E?=7684(15) keV and T1/2 = (16?5+13) ms were identified in the new isotope 198Fr. In addition, the half-life and ?-particle energy of 199Fr were measured with improved precision. The measured decay properties deduced for 199Fr and 198Fr suggest that there is an onset of ground-state deformation at N=112 in the Fr isotopes.

J. Uusitalo; J. Sarn; S. Juutinen; M. Leino; S. Eeckhaudt; T. Grahn; P. T. Greenlees; U. Jakobsson; P. Jones; R. Julin; S. Ketelhut; A.-P. Leppnen; M. Nyman; J. Pakarinen; P. Rahkila; C. Scholey; A. Semchenkov; J. Sorri; A. Steer; M. Venhart

2013-06-10T23:59:59.000Z

172

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

2005-11-01T23:59:59.000Z

173

Isotope Fractionation of Water during Evaporation without Condensation  

Science Journals Connector (OSTI)

Specifially, isotope fractionation factors associated with free evaporation (?evap) have been measured as a function of the isotopic composition and temperature of the liquid. ... Liquid-vapor fractionation of oxygen and hydrogen isotopes of water from the freezing to the critical temperature ...

Christopher D. Cappa; Walter S. Drisdell; Jared D. Smith; Richard J. Saykally; Ronald C. Cohen

2005-12-03T23:59:59.000Z

174

Simple, rapid method for the preparation of isotopically labeled formaldehyde  

DOE Patents [OSTI]

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.

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

175

Theoretical studies of transition metal surfaces as electrocatalysts for oxygen electroreduction  

E-Print Network [OSTI]

........................................................................... 42 5.1. Introduction ......................................................................................................... 42 5.2. Surface Structure, Changes Due to Alloying and Adsorbed Species................... 43 5.3. Electronic Structure... experiences upon alloying and when interacting with adsorbates... 42 Fig. 5.2. Surface relaxation on the Pt (111) and PdCo alloys. Both the clean surface and the one with oxygen adsorbed in the fcc hollow site is shown. All distances...

Lamas, Eduardo J.

2007-09-17T23:59:59.000Z

176

Application of the flooded-agglomerate model to study oxygen reduction on thin porous coating rotating disk electrode  

SciTech Connect (OSTI)

The study of the oxygen reduction reaction on dispersed platinum on carbon catalysts has been the object of several publications for over 20 years, because of the importance of these materials for application in various kinds of fuel cells. In this work, the thin-film/flooded-agglomerate model of gas diffusion electrodes was used to study the oxygen reduction reaction (ORR) on rotating disk electrodes with thin porous coating in alkaline solutions. Vulcan XC-72 carbon and 10, 20, and 30% w/w Pt/C catalysts were used as electrode materials. Fitting of the theoretical equations to the experimental data was employed to simulate the polarization characteristics of the ORR on the catalysts and to obtain the oxygen concentration profiles along the thickness of the flooded agglomerate as a function of the electrode potential and the structural parameters of the electrodes. The method was found to be a simple and adequate way to evaluate the performance of the supported catalysts. The predicted effect of doubling of the Tafel slope of the ORR due to diffusion of the reactant in the flooded agglomerate was confirmed experimentally. The kinetic parameters obtained for the ORR in alkaline media indicated that, for the lower Pt/C ratios, there is a strong participation of the carbon substrate in the catalysis of the reaction.

Perez, J.; Tanaka, A.A.; Gonzalez, E.R.; Ticianelli, E.A. (Sao Paulo Univ., Sao Carlos (Brazil). Inst. de Fisica e Quimica de Sao Carlos)

1994-02-01T23:59:59.000Z

177

ISOTOPES IN WATER  

Science Journals Connector (OSTI)

The study of isotopic prosies ha two different though related basic aims: an understanding of the way in which the water cycle in linked to alterations in climate, and how the carbon cycle has responded to the...

W. GEORGE DARLING; ADRIAN H. BATH

2006-01-01T23:59:59.000Z

178

Growth Rates, Stable Oxygen Isotopes (18O), and Strontium (Sr/Ca) Composition in Two Species of Pacific Sclerosponges (Acanthocheatetes wellsi and Astrosclera willeyana) with 18O Calibration and Application to Paleoceanography  

SciTech Connect (OSTI)

The isotopic and elemental composition of sclerosponge skeletons is used to reconstruct paleoceanographic records. Yet few studies have systematically examined the natural variability in sclerosponge skeletal {delta}{sup 18}O, growth, and Sr/Ca, and how that may influence the interpretation of sclerosponge proxy records. Here, we analyzed short records in seven specimens of Acanthocheatetes wellsi (high-Mg calcite, 21 mol% Mg) from Palau, four A. wellsi (high-Mg calcite, 21 mol% Mg) from Saipan, and three Astrosclera willeyana (aragonite) sclerosponges from Saipan, as well as one long record in an A. wellsi specimen from Palau spanning 1945-2001.5. In Saipan, species-specific and mineralogical effects appear to have a negligible effect on sclerosponge {delta}{sup 18}O, facilitating the direct comparison of {delta}{sup 18}O records between species at a given location. At both sites, A. wellsi {delta}{sup 18}O and growth rates were sensitive to environmental conditions, but Sr/Ca was not sensitive to the same conditions. High-resolution {delta}{sup 18}O analyses confirmed this finding as both A. wellsi and A. willeyana deposited their skeleton in accordance with the trends in isotopic equilibrium with seawater, though with a 0.27{per_thousand} offset in the case of A. willeyana. In the high-Mg-calcite species A. wellsi, Mg may be interfering with Sr incorporation into the skeleton. On multidecadal timescales, A. wellsi sclerosponge {delta}{sup 18}O in Palau tracked the Southern Oscillation Index variability post-1977, but not pre-1977, coincident with the switch in the Pacific Decadal Oscillation (PDO) at {approx}1976. This suggests that water mass circulation in the region is influenced by El Nino-Southern Oscillation variability during positive PDO phases, but not during negative ones.

Grottoli, A.; Adkins, J; Panero, W; Reaman, D; Moots, K

2010-01-01T23:59:59.000Z

179

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

E-Print Network [OSTI]

, E. A. Schweikert The determination of sub-part-per-m1111on levels of oxygen in germanium has been investigated. The method developed involves a post-irradiation chemi- cal separation of fluorine-18 produced via 0( He, p) F. 16 3 18 Selenium..., arsenic, and german1um rad1oisotopes formed from the matrix are successively precipitated and fluorine-18 recovered by distillation of fluosilicic ac1d and orecioitation of lanthanum fluor1de. The experimental detection limit for this method is es...

Francis, Georgann

2012-06-07T23:59:59.000Z

180

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

E-Print Network [OSTI]

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

Grossman, Ethan L.

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

It's Elemental - The Element Oxygen  

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

Nitrogen Nitrogen Previous Element (Nitrogen) The Periodic Table of Elements Next Element (Fluorine) Fluorine The Element Oxygen [Click for Isotope Data] 8 O Oxygen 15.9994 Atomic Number: 8 Atomic Weight: 15.9994 Melting Point: 54.36 K (-218.79°C or -361.82°F) Boiling Point: 90.20 K (-182.95°C or -297.31°F) Density: 0.001429 grams per cubic centimeter Phase at Room Temperature: Gas Element Classification: Non-metal Period Number: 2 Group Number: 16 Group Name: Chalcogen What's in a name? From the greek words oxys and genes, which together mean "acid forming." Say what? Oxygen is pronounced as OK-si-jen. History and Uses: Oxygen had been produced by several chemists prior to its discovery in 1774, but they failed to recognize it as a distinct element. Joseph

182

A study of QM/Langevin-MD simulation for oxygen-evolving center of photosystem II  

SciTech Connect (OSTI)

We have performed three QM/Langevin-MD simulations for oxygen-evolving complex (OEC) and surrounding residues, which are different configurations of the oxidation numbers on Mn atoms in the Mn{sub 4}O{sub 5}Ca cluster. By analyzing these trajectories, we have observed sensitivity of the change to the configuration of Mn oxidation state on O atoms of carboxyl on three amino acids, Glu354, Ala344, and Glu333. The distances from Mn to O atoms in residues contacting with the Mn{sub 4}O{sub 5}Ca cluster were analyzed for the three trajectories. We found the good correlation of the distances among the simulations. However, the distances with Glu354, Ala344, and Glu333 have not shown the correlation. These residues can be sensitive index of the changes of Mn oxidation numbers.

Uchida, Waka; Kimura, Yoshiro; Wakabayashi, Masamitsu [Department of Biomolecular Engineering, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Hatakeyama, Makoto; Ogata, Koji; Nakamura, Shinichiro [RIKEN Research Cluster for Innovation, Nakamura Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yokojima, Satoshi [Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan and RIKEN Research Cluster for Innovation, Nakamura Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2013-12-10T23:59:59.000Z

183

Experimental and theoretical study of pressure effects on hydrogen isotope fractionation in the system brucite-water at elevated temperatures  

Science Journals Connector (OSTI)

A detailed, systematic experimental and theoretical study was conducted to investigate the effect of pressure on equilibrium D/H fractionation between brucite (Mg(OH)2) and water at temperatures from 200 to 600C and pressures up to 800 MPa. A fine-grained brucite was isotopically exchanged with excess amounts of water, and equilibrium D/H fractionation factors were calculated by means of the partial isotope exchange method. Our experiments unambiguously demonstrated that the D/H fractionation factor between brucite and water increased by 4.4 to 12.4 with increasing pressure to 300 or 800 \\{MPa\\} at all the temperatures investigated. The observed increases are linear with the density of water under experimental conditions. We calculated the pressure effects on the reduced partition function ratios (?-factor) of brucite (300800 K and P ? 800 MPa) and water (400600C and P ? 100 MPa), employing a statistical-mechanical method similar to that developed by Kieffer (1982) and a simple thermodynamic method based on the molar volumes of normal and heavy waters, respectively. Our theoretical calculations showed that the reduced partition function ratio of brucite increases linearly with pressure at a given temperature (as much as 12.6 at 300 K and 800 MPa). The magnitude of the pressure effects rapidly decreases with increasing temperature. On the other hand, the ?-factor of water decreases 4 to 5 with increasing pressure to 100 \\{MPa\\} at 400 to 600C. Overall D/H isotope pressure effects combined from the separate calculations on brucite and water are in excellent agreement with the experimental results under the same temperature-pressure range. Our calculations also suggest that under the current experimental conditions, the magnitude of the isotope pressure effects is much larger on water than brucite. Thus, the observed pressure effects on D/H fractionation are common to other systems involving water. It is very likely that under some geologic conditions, pressure is an important variable in controlling D/H partitioning.

Juske Horita; David R. Cole; Veniamin B. Polyakov; Thomas Driesner

2002-01-01T23:59:59.000Z

184

Fuel Grading Study on a Low-Enriched Uranium Fuel Design for the High Flux Isotope Reactor  

SciTech Connect (OSTI)

An engineering design study that would enable the conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium to low-enriched uranium fuel is ongoing at Oak Ridge National Laboratory. The computational models used to search for a low-enriched uranium (LEU) fuel design that would meet the requirements for the conversion study, and the recent results obtained with these models during FY 2009, are documented and discussed in this report. Estimates of relevant reactor performance parameters for the LEU fuel core are presented and compared with the corresponding data for the currently operating high-enriched uranium fuel core. These studies indicate that the LEU fuel design would maintain the current performance of the HFIR with respect to the neutron flux to the central target region, reflector, and beam tube locations.

Ilas, Germina [ORNL; Primm, Trent [ORNL

2009-11-01T23:59:59.000Z

185

E-Print Network 3.0 - allende meteorite isotopically Sample Search...  

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

of Geophysical Sciences, University of Chicago Collection: Geosciences 31 RARE EARTH ELEMENTS AND OXYGEN ISOTOPES IN ALLENDE CHONDRULES AS EVIDENCE FOR CAI MIXING IN...

186

Design Study for a Low-Enriched Uranium Core for the High Flux Isotope Reactor, Annual Report for FY 2008  

SciTech Connect (OSTI)

This report documents progress made during FY 2008 in studies of converting the High Flux Isotope Reactor (HFIR) from highly 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 reactor performance from the current level. Results of selected benchmark studies imply that calculations of LEU performance are accurate. Scoping experiments with various manufacturing methods for forming the LEU alloy profile are presented.

Primm, Trent [ORNL; Chandler, David [ORNL; Ilas, Germina [ORNL; Miller, James Henry [ORNL; Sease, John D [ORNL; Jolly, Brian C [ORNL

2009-03-01T23:59:59.000Z

187

Fe isotope fractionation during phase separation in the NaClH2O system: An experimental study with implications for seafloor hydrothermal vents  

Science Journals Connector (OSTI)

Abstract Phase separation has been proposed as a possible mechanism contributing to the Fe isotope composition of hydrothermal fluids at mid-ocean ridges. The uncertainty results largely from the emphasis on field data that can involve competing processes that obscure cause and effect of any one process. To better understand the potential significance of phase separation in the NaClFeH2O system on Fe isotope fractionation, temperature and pressure of a Fe-bearing NaCl fluid in a titanium flow reactor were carefully adjusted to produce vapor liquid halite, while the Fe isotope composition between coexisting phases was monitored. Two different PT regions were emphasized: (1) 424420?C, 35.231.5 MPa; and (2) 464466?C, 29.824.7 MPa. Both regions were chosen to simulate the range of physical conditions that are experienced by hydrothermal fluids at mid-ocean ridges (MORs). Decompression induced phase separation in both PT regions results in the vapor phase becoming enriched in the heavier isotopes of Fe, as the Fe/Cl ratio decreases. The coexisting NaCl-rich liquid phase remains essentially constant with respect to Fe/Cl ratio and Fe isotope composition. Coinciding with the lowest vapor chlorinity in the vaporliquid stability field, the Fe/Cl ratio of the vapor abruptly increases, while the Fe isotope fractionation between the vapor and liquid ( 10 3 ln ? ? V / L 56 / 54 ) reached a maximum value of + 0.145 0.048 . Subsequently, Fe isotope fractionation decreased upon transition into the vaporhalite stability field (PT region 2). We infer that the observed Fe isotope fractionation between vapor liquid halite is caused by differences in Fe speciation among coexisting chloride-bearing phases. The experimental study confirms for the first time that measurable Fe isotope variability can result from phase separation in high temperature hydrothermal systems. The species-dependent Fe isotope fractionation reported here is small relative to predicted mineralmineral and mineralfluid fractionations, especially if redox effects are involved as might occur during vent fluidseawater mixing reactions and/or magmatic activity associated with seafloor eruptive episodes.

Drew D. Syverson; Nicholas J. Pester; Paul R. Craddock; William E. Seyfried Jr.

2014-01-01T23:59:59.000Z

188

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

189

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

190

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

SciTech Connect (OSTI)

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

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

2012-10-01T23:59:59.000Z

191

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...

192

Isotopic fractionation of carbon, deuterium and nitrogen : a full chemical study  

E-Print Network [OSTI]

Context. The increased sensitivity and high spectral resolution of millimeter telescopes allow the detection of an increasing number of isotopically substituted molecules in the interstellar medium. The 14N/ 15N ratio is difficult to measure directly for carbon containing molecules. Aims. We want to check the underlying hypothesis that the 13C/ 12C ratio of nitriles and isonitriles is equal to the elemental value via a chemical time dependent gas phase chemical model. Methods. We have built a chemical network containing D, 13C and 15N molecular species after a careful check of the possible fractionation reactions at work in the gas phase. Results. Model results obtained for 2 different physical conditions corresponding respectively to a moderately dense cloud in an early evolutionary stage and a dense depleted pre-stellar core tend to show that ammonia and its singly deuterated form are somewhat enriched in 15N, in agreement with observations. The 14N/ 15N ratio in N2H+ is found to be close to the elemental v...

Roueff, E; Hickson, K M

2015-01-01T23:59:59.000Z

193

Definition: Isotopic Analysis- Fluid | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Isotopic Analysis- Fluid Jump to: navigation, search Dictionary.png Isotopic Analysis- Fluid Isotopes are atoms of the same element that have different numbers of neutrons. An isotopic analysis looks at a particular isotopic element(s) in a given system, while the conditions which increase/decrease the number of neutrons are well understood and measurable. Fluid isotopes are used to characterize a fluids origin, age, and/or interaction with rocks or other fluids based on unique isotopic ratios or concentrations.[1] View on Wikipedia Wikipedia Definition Isotope geochemistry is an aspect of geology based upon study of the relative and absolute concentrations of the elements and their isotopes in

194

Stable isotope patterns found in early Eocene equid tooth rows of North America: Implications for reproductive behavior and paleoclimate  

Science Journals Connector (OSTI)

Abstract Reproductive behaviors of early Eocene equids were likely different from their modern-day counterparts as a result of their small body size and warmer global temperatures. To better understand the paleoenvironment and ecology of these early horses, teeth of Protorohippus montanum jaws from a single stratigraphic locality in early Eocene sedimentary deposits of Wyoming were sampled for oxygen and carbon isotope analysis. These enamel data along with an inferred body mass of ~7.5kg suggests that adult teeth formed over a matter of months, with the final tooth erupting at ~1.3years of age. Thus, average isotopic values from each tooth likely represent environmental conditions from a single season. Results indicate two isotopic patterns. In the case of isotopic pattern A, the second forming molars (m/2s) have significantly lower isotopic ratios compared to other teeth within the jaw. This suggests the first forming molars (m/1s) formed during a cooling fall season, followed by formation of the m/2s during the cooler winter. In the case of isotopic pattern B, results suggest that m/1s formed during a warming spring season, while the m/2s formed during the following warmer summer season. Isotopic ratios of m/1s may represent an individual's birth season (or in utero season, depending on timing of initial formation), implying that early equids experienced at least two birth seasons per year. These results suggest that temperatures and reduced seasonality of the early Eocene played a strong role in early equid birth cycles. Lastly, the mean and variance in carbon and oxygen isotope ratios was not significantly different across tooth positions of all jaws when all individuals were grouped together, regardless of their pattern assignment. Such results indicate that isotopic data from fourth premolars, first molars, second molars, and third molars can be combined for purposes of temporal reconstructions of paleoclimate, thus increasing the potential sample sizes for these types of studies.

Abigail R. DAmbrosia; William C. Clyde; Henry C. Fricke; Amy E. Chew

2014-01-01T23:59:59.000Z

195

Isotope (?13C and ?18O) compositions of dolomites from the Permian evaporitic sequences of the Eastern Russian Plate: Evidence from the Syukeevo gypsum deposit  

Science Journals Connector (OSTI)

Carbon and oxygen isotope compositions has been studied in dolomites of the Syukeevo gypsum deposit located in the Eastern Russian Plate. Values of ?13C in the dolomites vary from 0.3 to 6.6 ; ?18O, from 28.0 to...

R. Kh. Sungatullin; V. N. Kuleshov; R. I. Kadyrov

2014-09-01T23:59:59.000Z

196

Solvent Isotope-Induced Equilibrium Perturbation for Isocitrate Lyase  

Science Journals Connector (OSTI)

Solvent Isotope-Induced Equilibrium Perturbation for Isocitrate Lyase ... Solvent isotopic composition can influence both the rates of enzyme-catalyzed reactions (solvent kinetic isotope effects) and, in the case of solvent-derived deuterium incorporation into nonexchangeable CH bonds in products, solvent equilibrium isotope effects. ... In this study, we report the solvent isotope-induced transient change in the concentration and isotopic composition of the reactants. ...

Christine E. Quartararo; Timin Hadi; Sean M. Cahill; John S. Blanchard

2013-11-21T23:59:59.000Z

197

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

E-Print Network [OSTI]

and hydrogen, oxygen, and strontium isotopes. dD and d18 O values fall close to the global meteoric water lineRegional groundwater flow paths in Trans-Pecos, Texas inferred from oxygen, hydrogen, and strontium isotopes, and major ion chemistry are used to con- strain flow paths in a fracture-controlled regional

Banner, Jay L.

198

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This report covers the following tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints; Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability; Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres; Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures; Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability; and Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-04-01T23:59:59.000Z

199

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

In the present quarter, oxygen transport perovskite ceramic membranes 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.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-07-01T23:59:59.000Z

200

The role of oxygen in hydrogen sensing by a platinum-gate silicon carbide gas sensor: An ultrahigh vacuum study  

E-Print Network [OSTI]

The role of oxygen in hydrogen sensing by a platinum-gate silicon carbide gas sensor: An ultrahigh conditions that elucidate the role of oxygen in the functioning of silicon carbide field-effect gas sensors hydrogen-depleted state; competition between hydrogen oxidation and hydrogen diffusion to metal/ oxide

Tobin, Roger G.

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201

Density Functional Theory Study of an Oxygen Reduction Reaction on a Pt3Ti Alloy Electrocatalyst  

Science Journals Connector (OSTI)

Besides activity for ORR, the long-term stability of cathode electrocatalyst in a harsh acidic environment is a serious challenge in the development of durable electrocatalysts for wide scale application of PEMFC. ... To discover less expensive and more active cathode catalysts, a novel combinatorial workflow was developed to study alloy-based electrocatalysts. ...

Shyam Kattel; Zhiyao Duan; Guofeng Wang

2013-03-20T23:59:59.000Z

202

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)

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.

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

203

Isotopic equilibration of carbon monoxide catalyzed by supported ruthenium  

SciTech Connect (OSTI)

Isotopic equilibration of carbon monoxide catalyzed by supported ruthenium was studied with oxygen-18 and carbon-13 labeled carbon monoxide in the presence and absence of hydrogen. The results showed that carbon monoxide was present on commercial alumina-supported ruthenium in a reactive undissociated form at 373/sup 0/K; that it adsorbed as a single carbonyl and in a geminal dicarbonyl form; and that hydrogen inhibited the exchange reaction by competitive adsorption and by stabilizing the carbonyl bond. The results elucidate the carbon monoxide methanation and Fischer-Tropsch reactions on this catalyst.

Bossi, A. (Cent. Ric. Novara); Zanderighi, L.; Carnisio, G.; Garbassi, F.; Giunchi, G.; Petrini, G.

1980-09-01T23:59:59.000Z

204

Oxygen Transport Ceramic Membranes Quarterly Report  

E-Print Network [OSTI]

/Reaction rates in Ion 21 Transport Membranes using Isotope Tracer and Transient Kinetic Techniques CONCLUSIONS 30Oxygen Transport Ceramic Membranes Quarterly Report January 2003 ­ March 2003 Principal Authors on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane

Eagar, Thomas W.

205

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2000-10-01T23:59:59.000Z

206

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

SciTech Connect (OSTI)

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)

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

207

Experimental Study of a New PVC Foam Insulation System for Liquid-Hydrogen-Liquid-Oxygen Space Vehicles  

Science Journals Connector (OSTI)

This paper discusses the development of a rigid external foam insulation for liquid-hydrogen-liquid-oxygen space vehicles...1...], dealing with the use of Klegecell G 300,* a PVC closed-cell foam. This foam does ...

F. J. Muller

1971-01-01T23:59:59.000Z

208

An experimental study of magnesium-isotope fractionation in chlorophyll-a photosynthesis  

E-Print Network [OSTI]

of America 94 , 13351-13356. Jasper P. and Silver S. (1977)concentration in the cytoplasm (Jasper and Silver, 1977).and active transport (Jasper and Silver, 1977). Studies have

Black, J R; Yin, Q Z; Casey, W H

2006-01-01T23:59:59.000Z

209

High-pressure neutron diffraction study on HD isotope effects in brucite  

Science Journals Connector (OSTI)

A neutron powder diffraction study of hydrogenated and deuterated brucite was conducted at ambient temperature and at...a axis, parallel to the sheets of MgO octahedra, decrease only slightly with pressure with ...

Juske Horita; Antnio M. dos Santos

2010-12-01T23:59:59.000Z

210

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

E-Print Network [OSTI]

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 ...

McNichol, Ann P., 1956-

1986-01-01T23:59:59.000Z

211

Levels of isotopes Pa233,235,237 and Ac229,231 studied by the (t ,?) reaction  

Science Journals Connector (OSTI)

The U234(t ,?)Pa233, U236(t ,?)Pa 235, U238(t ,?)Pa 237, Th230(t ,?)Ac 229, and Th232(t ,?)Ac 231 reactions were studied with a 15-MeV triton beam. The reaction results are interpreted in terms of a distorted-wave-Born-approximation analysis. Theoretical cross sections, calculated in the framework of the Nilsson model with pairing and Coriolis interactions included, are compared with experimental values. The following Nilsson proton configurations are identified in all of the residual nuclei: 1/2+[400], 3/2+[402], 3/2+[651], 1/2-[530]. The 1/2-[541] and 9/2-[514] configurations are tentatively assigned. Due to the increase in deformation with neutron number, the ground state configuration of the Pa isotopes changes from 3/2-[530] to 1/2+[400] as A increases.NUCLEAR REACTIONS U234(t ,?), U236(t ,?), U238(t ,?), Th230(t ,?), and Th232-(t ,?), E=15 MeV, measured ?(E?,?), deduced levels, J, ?, K, enriched targets.

R. C. Thompson; W. Wilcke; J. R. Huizenga; W. K. Hensley; D. G. Perry

1977-06-01T23:59:59.000Z

212

Ab-initio study of hydrogen doping and oxygen vacancy at anatase TiO{sub 2} surface  

SciTech Connect (OSTI)

Density functionalpseudopotential calculations were performed to study the effects of hydrogen doping and oxygen vacancy, both individually and together, on the electronic structure and stability of (001) surface of TiO{sub 2} in the anatase phase. Based on our calculations, O/Ti termination is the most stable one, and it appears that p-states of deep and surface O atoms and d-orbitals of surface Ti atoms have roles in the valence band and, the conduction band comes from the d-orbitals of deep Ti atoms. Although, no considerable change was seen during H doping, a mid-gap state appeared below the conduction band in the O vacancy configuration. In the framework of ab-initio atomistic thermodynamics, we argue that the anatase TiO{sub 2} prefers a defected O layer termination in the [001] direction. The obtained electronic structures indicate that H doping in the bulk creates the empty mid-gap state below the conduction band and hence decreases the band gap of the system. This phenomenon may explain the enhanced photocatalytic activity of the anatase TiO{sub 2} (001) surface after hydrogenation.

Sotoudeh, M.; Mohammadizadeh, M. R., E-mail: zadeh@ut.ac.ir [Superconductivity Research Laboratory (SRL), Department of Physics, University of Tehran, North Kargar Ave., P.O. Box 14395-547, Tehran (Iran, Islamic Republic of); Hashemifar, S. J. [Departement of Physics, Isfahan University of Technology, 84156 83111, Isfahan (Iran, Islamic Republic of)] [Departement of Physics, Isfahan University of Technology, 84156 83111, Isfahan (Iran, Islamic Republic of); Abbasnejad, M. [Department of Physics, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)] [Department of Physics, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

2014-02-15T23:59:59.000Z

213

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

E-Print Network [OSTI]

?-conjugating substituent is distal to the oxazolidinone but decreased steric interaction when the Ï?-conjugating substituent is proximal to the oxazolidinone. Dynamic effects were studied in Diels-Alder reaction between acrolein and methyl vinyl ketone. This reaction...

Wang, Zhihong

2007-04-25T23:59:59.000Z

214

Slow Neutron Scattering by the Titanium Isotopes  

Science Journals Connector (OSTI)

Neutron diffraction studies are reported on isotopically enriched samples of TiO2 from which are evaluated the coherent scattering amplitudes of the titanium isotopes. Scattering amplitudes of +0.48, +0.33, -0.58, +0.08, and +0.5510-12 cm were established for the titanium isotopes of mass 46, 47, 48, 49, and 50, respectively. The major isotope Ti48 is thus responsible for the anomalous scattering amplitude, -0.3410-12 cm, characteristic of the normal element. Pronounced nuclear scattering resonance effects on the observed neutron scattering are suggested to occur for most of the isotopes.

C. G. Shull; M. K. Wilkinson; M. H. Mueller

1960-05-01T23:59:59.000Z

215

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

SciTech Connect (OSTI)

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.

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

216

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

SciTech Connect (OSTI)

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.

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

217

Abstract Variation in the carbon isotopic composition of ecosystem respiration (13CR) was studied for 3 years  

E-Print Network [OSTI]

coast to the eastern side of the Cascade Mountains (a 250-km transect). Mean annual precipita- tion of gas exchange and associated changes in photosynthetic carbon isotope discrimination. Recent freeze). The extent to which and 13CR vary could po- tentially alter conclusions about the timing and nature

Ehleringer, Jim

218

lead-isotope dating  

Science Journals Connector (OSTI)

lead-isotope dating, lead-lead dating, lead-isotope age measurement, lead-lead age measurement ? Blei-Isotopen(-Alters)bestimmung, f, Blei-Isotopen-Datierung

2014-08-01T23:59:59.000Z

219

isotopic ratio | EMSL  

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

isotopic ratio isotopic ratio Leads No leads are available at this time. Magnesium behavior and structural defects in Mg+ ion implanted silicon carbide. Abstract: As a candidate...

220

Study of the relation between oxygen vacancies and ferromagnetism in Fe-doped TiO{sub 2} nano-powders  

SciTech Connect (OSTI)

In this work, we present an experimental and theoretical study of structural and magnetic properties of Fe doped rutile TiO{sub 2} nanopowders. We show that Fe-doping induces the formation of oxygen vacancies in the first-sphere coordination of iron ions, which are in +2 and +3 oxidation states. We found that Fe ions form dimers that share one oxygen vacancy in the case of Fe{sup 3+} and two oxygen vacancies in the case of Fe{sup 2+}. The saturation magnetization is almost independent of iron concentration and slightly increases with the relative fraction of Fe{sup 2+}. Ab initio calculations show that two Fe ions sharing an oxygen vacancy are coupled ferromagnetically, forming a bound magnetic polaron (BMP), but two neighbor BMPs are aligned antiparallel to each other. Extra electron doping plays a fundamental role mediating the magnetic coupling between the ferromagnetic entities: carriers, possibly concentrated at grain boundaries, mediate between the BMP to produce ferromagnetic alignment.

Mudarra Navarro, Azucena M.; Rodrguez Torres, Claudia E., E-mail: torres@fisica.unlp.edu.ar; Fabiana Cabrera, A. [Departamento de Fsica Facultad de Ciencias Exactas, UNLP, Instituto de Fsica La Plata, CCT-La Plata, CONICET, CC 67, 1900 La Plata (Argentina); Bilovol, Vitaliy [Laboratorio de Slidos Amorfos, INTECIN-CONICET, Facultad de Ingeniera, UBA, Av. Paseo Coln 850, Buenos Aires C1063ACV (Argentina); Errico, L. A. [Departamento de Fsica Facultad de Ciencias Exactas, UNLP, Instituto de Fsica La Plata, CCT-La Plata, CONICET, CC 67, 1900 La Plata (Argentina); Universidad Nacional del Noroeste de la Pcia. de Buenos Aires (UNNOBA), Monteagudo 2772, Pergamino. CP 2700 Buenos Aires (Argentina); Weissmann, M. [Depto. de Fsica, Comisin Nacional de Energa Atmica, Av. del Libertador 8250, 1429 Buenos Aires (Argentina)

2014-06-14T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

E-Print Network 3.0 - ameliorating reactive oxygen Sample Search...  

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

structure and surface relaxation Summary: reactivity of each type of oxygen the adsorption of hydrogen over different oxygen sites is studied. Full... oxygen is the reactive...

222

Thermodynamic and kinetic studies of a catalytic process to convert glycerol into solketal as an oxygenated fuel additive  

E-Print Network [OSTI]

exchange resin Kinetics a b s t r a c t Glycerol is a byproduct of biodiesel industry and can be converted as an oxygenated fuel additive Malaya R. Nanda a , Zhongshun Yuan a , Wensheng Qin b , Hassan S. Ghaziaskar c was completely eliminated above 400 rpm. Moisture content demonstrated an adverse effect on the yield

Qin, Wensheng

223

PHYSICAL REVIEW B 84, 245206 (2011) First-principles study of band gap engineering via oxygen vacancy doping  

E-Print Network [OSTI]

formulate guidelines that can be used to predict the location of oxygen vacancies in perovskite solid transport of O2- ions through the oxide electrolyte membrane over a range of temperatures. In solar energy several chemical compositions and different cation arrangements for the two Zr-modified solid solutions

Rappe, Andrew M.

224

Surface reactivity and oxygen migration in amorphous indium-gallium-zinc oxide films annealed in humid atmosphere  

SciTech Connect (OSTI)

An isotope tracer study, i.e., {sup 18}O/{sup 16}O exchange using {sup 18}O{sub 2} and H{sub 2}{sup 18}O, was performed to determine how post-deposition annealing (PDA) affected surface reactivity and oxygen diffusivity of amorphous indiumgalliumzinc oxide (a-IGZO) films. The oxygen tracer diffusivity was very high in the bulk even at low temperatures, e.g., 200?C, regardless of PDA and exchange conditions. In contrast, the isotope exchange rate, dominated by surface reactivity, was much lower for {sup 18}O{sub 2} than for H{sub 2}{sup 18}O. PDA in a humid atmosphere at 400?C further suppressed the reactivity of O{sub 2} at the a-IGZO film surface, which is attributable to OH-terminated surface formation.

Watanabe, Ken, E-mail: Watanabe.Ken@nims.go.jp [International Center for Young Scientists (ICYS-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)] [International Center for Young Scientists (ICYS-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan); Lee, Dong-Hee [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan) [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Sakaguchi, Isao; Haneda, Hajime [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan)] [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Nomura, Kenji [Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan)] [Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Kamiya, Toshio [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan) [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Hosono, Hideo [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan) [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Ohashi, Naoki, E-mail: Ohashi.Naoki@nims.go.jp [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan) [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan)

2013-11-11T23:59:59.000Z

225

Mitochondrial reactive oxygen species and cancer  

E-Print Network [OSTI]

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 ...

Chandel, Navdeep S

226

Soil Studies with Isotopes  

Science Journals Connector (OSTI)

... reference are even strained to include the use of steam from nuclear reactors for the desalination of water. The proceedings are divided into five sections dealing respectively with equipment and ... moisture profile; soil water movement ; the interaction between soil, vegetation and water; and desalination of water for agriculture. Among the most valuable contributions are comparisons between the performance ...

E. C. CHILDS

1968-06-15T23:59:59.000Z

227

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals. This project has the following 6 main tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2001-12-01T23:59:59.000Z

228

Dipole strength distributions in the stable Ba isotopes {sup 134-138}Ba: A study in the mass region of a nuclear shape transition  

SciTech Connect (OSTI)

The low-lying dipole strength distributions in the odd-mass isotopes {sup 135,137}Ba were studied in nuclear resonance fluorescence experiments (NRF) performed at the Stuttgart Dynamitron facility using bremsstrahlung beams with end point energies of 4.1, 3.1, and 2.5 MeV. Numerous excited states, most of them unknown so far, were observed in the excitation energy range up to 4 MeV. Detailed spectroscopic information has been obtained on excitation energies, decay widths, decay branching ratios, and transition probabilities. The results for {sup 137}Ba are compared with calculations in the framework of the Quasiparticle-Phonon Model. The new data for {sup 135,137}Ba complete the systematics of low-lying dipole excitations as observed for the even Ba isotopes {sup 134,136,138}Ba in previous NRF experiments in Stuttgart. The complete systematics within the Ba isotopic chain, exhibiting a nuclear shape transition, is discussed with respect to E1 two-phonon excitations, M1 scissors mode excitations, and in regard to the new critical point symmetries.

Scheck, M.; Garrel, H. von; Belic, D.; Kneissl, U.; Kohstall, C.; Nord, A.; Pitz, H.H.; Stedile, F. [Institut fuer Strahlenphysik, Universitaet Stuttgart, D-70569 Stuttgart (Germany); Tsoneva, N. [Institut fuer Theor. Physik, Universitaet Giessen, D-35392 Giessen (Germany); Brentano, P. von; Fransen, C.; Gade, A.; Jolie, J.; Linnemann, A.; Pietralla, N.; Werner, V. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Cologne (Germany); Stoyanov, C. [Institute for Nuclear Research and Nuclear Energy, 1784 Sofia (Bulgaria)

2004-10-01T23:59:59.000Z

229

Isotope Science and Production  

E-Print Network [OSTI]

of Energy National Isotope Program http://www.nuclear.energy.gov/isotopes/nelsotopes2a.html Isotopes for Environmental Science Isotopes produced at Los Alamos National Laboratory are used as environmental tracers change and its effects. Los Alamos National Laboratory can produce Si-32 needed for oceanographic tracing

230

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

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.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2003-01-01T23:59:59.000Z

231

Local origins of interdecadal Pacific variability in the tropical and North Pacific Ocean: evidence from a comparative study of coral oxygen isotope records  

Science Journals Connector (OSTI)

Interdecadal Pacific variability (IPV) is commonly observed in both the tropical and mid-latitude Pacific Ocean, and has a widespread influence on surface climate in the Pan-Pacific Basin. This variability is rec...

Wenfeng Deng; Gangjian Wei

2014-08-01T23:59:59.000Z

232

The Stroke Oxygen Study (SO2S) - a multi-center, study to assess whether routine oxygen treatment in the first 72hours after a stroke improves long-term outcome: study protocol for a randomized controlled trial  

Science Journals Connector (OSTI)

The remit of the Data Monitoring and Safety Committee (DMSC) will be to ensure that patients are ... studies, and any other analyses that the DMSC may request. The DMSC will advise the chair of the TSC...

Christine Roffe; Tracy Nevatte; Peter Crome; Richard Gray; Julius Sim

2014-03-01T23:59:59.000Z

233

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones  

Science Journals Connector (OSTI)

Teeth and bones of fossil vertebrates can preserve a record of Quaternary terrestrial environments in the form of isotopic compositions of carbon (13C/12C), nitrogen (15N/14N), and oxygen (18O/16O). These isotopic signatures in teeth and bones have yielded valuable information on the extent of savanna environments under tropical climates, on the ancient levels of aridity, on the spread of dense forests at the beginning of the Holocene, and on the paleodiet of hominids and their associated fauna.

H. Bocherens; D.G. Drucker

2007-01-01T23:59:59.000Z

234

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones  

Science Journals Connector (OSTI)

Abstract Teeth and bones of fossil vertebrates can preserve a record of Quaternary terrestrial environments in the form of the isotopic compositions of carbon (13C/12C), nitrogen (15N/14N), and oxygen (18O/16O). These isotopic signatures in teeth and bones have yielded valuable information on the extent of savanna environments under tropical climates, on the ancient levels of aridity, on the spread of dense forests at the beginning of the Holocene, and on the paleodiet of Hominids and their associated fauna.

H. Bocherens; D.G. Drucker

2013-01-01T23:59:59.000Z

235

Light-induced oxygen-ordering dynamics in ,,Y,Pr...Ba2Cu3O6.7: A Raman spectroscopy and Monte Carlo study  

E-Print Network [OSTI]

Light-induced oxygen-ordering dynamics in ,,Y,Pr...Ba2Cu3O6.7: A Raman spectroscopy and Monte Carlo energy barrier which impedes oxygen movement in the plane unless the oxygen atoms are excited by light for oxygen reordering in the chain plane being at the origin of Raman photobleaching and related effects. DOI

Nabben, Reinhard

236

The Quest for the Heaviest Uranium Isotope  

E-Print Network [OSTI]

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.

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

2011-07-06T23:59:59.000Z

237

Water column oxygen demand and sediment oxygen flux: patterns of oxygen depletion in tidal creeks  

Science Journals Connector (OSTI)

Five study sites were chosen in Futch Creek, Hewletts Creek and Pages Creek,...1). Sites were chosen to reflect a range in the values of dissolved oxygen levels, chlorophyll a concentrations and nutrient (nitroge...

Tara A. MacPherson; Lawrence B. Cahoon; Michael A. Mallin

2007-07-01T23:59:59.000Z

238

In situ Carbon 13 and Oxygen 18 Ratios of Atmospheric CO2 from Cape Grim,  

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

Oxygen Isotopes and Ratios » 13C and 18O Oxygen Isotopes and Ratios » 13C and 18O Ratios, Atmospheric CO2, Cape Grim In situ Carbon 13 and Oxygen 18 Ratios of Atmospheric CO2 from Cape Grim, Tasmania, Australia: 1982-1993 DOI: 10.3334/CDIAC/atg.db1014 data Data Investigators Francey R. J. and C. E. Allison Description Since 1982, a continuous program of sampling atmospheric CO2 to determine stable isotope ratios has been maintained at the Australian Baseline Air Pollution Station, Cape Grim, Tasmania (40°, 40'56"S, 144°, 41'18"E). The process of in situ extraction of CO2 from air, the preponderance of samples collected in conditions of strong wind from the marine boundary layer of the Southern Ocean, and the determination of all isotope ratios relative to a common high purity CO2 reference gas with isotopic δ13C close to

239

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

240

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

SciTech Connect (OSTI)

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)

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

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

E-Print Network 3.0 - atmospheric oxygen concentration Sample...  

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

< 1 2 3 4 5 > >> 1 Sulfur and oxygen isotope composition of the atmosphere in Saxony (Germany) Tichomirowa et al. Summary: Conclusions Mean SO2 concentrations in 2003 12;Sulfur...

242

Isotopically pumped isotopic CF4 laser  

Science Journals Connector (OSTI)

Single-mode optical pumping of CF4 to generate 16-m frequencies has been extended to include the isotopic species 12CF4,...

Eckhardt, Roger; Telle, John; Haynes, Larry

1982-01-01T23:59:59.000Z

243

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)

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.

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

244

Artificial oxygen transport protein  

DOE Patents [OSTI]

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.

Dutton, P. Leslie

2014-09-30T23:59:59.000Z

245

Modeling non-steady state radioisotope transport in the vadose zone--A case study using uranium isotopes at Pena Blanca, Mexico  

SciTech Connect (OSTI)

Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and {sup 234}U/{sup 238}U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and {alpha}-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Pena Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced {sup 234}U/{sup 238}U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using {sup 234}U/{sup 238}U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

Ku, T. L.; Luo, S.; Goldstein, S. J.; Murrell, M. T.; Chu, W. L.; Dobson, P. F.

2009-06-01T23:59:59.000Z

246

Water geochemistry study of Indian Wells Valley, Inyo and Kern Counties,  

Open Energy Info (EERE)

geochemistry study of Indian Wells Valley, Inyo and Kern Counties, geochemistry study of Indian Wells Valley, Inyo and Kern Counties, California. Supplement. Isotope geochemistry and Appendix H. Final report Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Water geochemistry study of Indian Wells Valley, Inyo and Kern Counties, California. Supplement. Isotope geochemistry and Appendix H. Final report Details Activities (4) Areas (4) Regions (0) Abstract: Hydrogen and oxygen isotope data on waters of Indian Wells Valley, the Sierra, Rose Valley, and Coso thermal and nonthermal waters were studied. The isotope ratios of Sierran waters are a function of latitude with both ratios becoming depleted in the heavier isotopes from south to north. Assuming that groundwater recharge is from the Sierra, recharge areas for the various groundwater types can be designated.

247

Advanced isotope separation  

SciTech Connect (OSTI)

The Study Group briefly reviewed the technical status of the three Advanced Isotope Separation (AIS) processes. It also reviewed the evaluation work that has been carried out by DOE's Process Evaluation Board (PEB) and the Union Carbide Corporation-Nuclear Division (UCCND). The Study Group briefly reviewed a recent draft assessment made for DOE staff of the nonproliferation implications of the AIS technologies. The staff also very briefly summarized the status of GCEP and Advanced Centrifuge development. The Study Group concluded that: (1) there has not been sufficient progress to provide a firm scientific, technical or economic basis on which to select one of the three competing AIS processes for full-scale engineering development at this time; and (2) however, should budgetary restraints or other factors force such a selection, we believe that the evaluation process that is being carried out by the PEB provides the best basis available for making a decision. The Study Group recommended that: (1) any decisions on AIS processes should include a comparison with gas centrifuge processes, and should not be made independently from the plutonium isotope program; (2) in evaluating the various enrichment processes, all applicable costs (including R and D and sales overhead) and an appropriate discounting approach should be included in order to make comparisons on a private industry basis; (3) if the three AIS programs continue with limited resources, the work should be reoriented to focus only on the most pressing technical problems; and (4) if a decision is made to develop the Atomic Vapor Laser Isotope Separation process, the solid collector option should be pursued in parallel to alleviate the potential program impact of liquid collector thermal control problems.

Not Available

1982-05-04T23:59:59.000Z

248

Isotope Geothermometry | Open Energy Information  

Open Energy Info (EERE)

Isotope Geothermometry Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Isotope Geothermometry Details Activities (0) Areas (0) Regions (0)...

249

It's Elemental - Isotopes of the Element Nitrogen  

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

Carbon Carbon Previous Element (Carbon) The Periodic Table of Elements Next Element (Oxygen) Oxygen Isotopes of the Element Nitrogen [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 14 99.636% STABLE 15 0.364% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 10 No Data Available Proton Emission 100.00% 11 5.49×10-22 seconds Proton Emission 100.00% 12 11.000 milliseconds Electron Capture 100.00% 13 9.965 minutes Electron Capture 100.00% 14 STABLE - - 15 STABLE - - 16 7.13 seconds Beta-minus Decay 100.00% Beta-minus Decay with delayed Alpha Decay 1.2×10-3 % 17 4.173 seconds Beta-minus Decay 100.00%

250

Carbonate clumped isotope constraints on Silurian ocean temperature and seawater d18  

E-Print Network [OSTI]

temperature is the carbonate-water oxygen isotope exchange thermometer, also known as the carbonate d18 O thermometer (Urey, 1947). This thermometer is based on the temperature dependence of the fractionation between

251

THE ISOTOPES OF AMERICIUM  

E-Print Network [OSTI]

spectrographic analysis of the americium samples. It is a48 J'---_I" THE ISOTOPES OF AMERICIUM K. Street, Jr. , A.Elements THE ISOTOPES OF AMERICIUM K. Street, Jr. , A.

Street, K.; Ghiroso, A.; Seaborg, G.T.

2008-01-01T23:59:59.000Z

252

Electrochemical Isotope Effect and Lithium Isotope Separation  

Science Journals Connector (OSTI)

In a series of papers Kavner et al. (2005, 2008)(2, 3) derive an equation predicting isotopic fractionation due to an electrochemical isotope effect (?EIE), defined by the ratio of electron transfer rates (k?/k) for isotopically substituted species (prime for heavy isotopologues): where v, ?G, kB, T, m, ?eq, QP/QR, z, e, and ? denote collision frequency, activation free energy, Boltzmanns constant, temperature, mass in motion, equilibrium fractionation factor, partition function ratio of abundant isotopologues of product (P) and reactant (R), number of electrons, charge of electron, and Marcus reorganization energy, respectively. ... fractional isotope evolution of Zn isotopes during an electroplating process which stepwise removes most of the Zn from the aq. ...

Jay R. Black; Grant Umeda; Bruce Dunn; William F. McDonough; Abby Kavner

2009-07-06T23:59:59.000Z

253

Isotope Effect in Adhesion  

Science Journals Connector (OSTI)

Isotope Effect in Adhesion ... We report the first observation of an isotope effect in adhesion. ... The results are presented in Figure 3. Clearly, the isotope effect is very significant, substantiating the proposed H-bonding interactions between the PDMS and Si?OH(D) surfaces. ...

Gun Young Choi; Abraham Ulman; Yitzhak Shnidman; Walter Zurawsky; Cathy Fleischer

2000-05-25T23:59:59.000Z

254

Isotopic Analysis-Fluid At Yellowstone Caldera Geothermal Region (1977) |  

Open Energy Info (EERE)

Isotopic Analysis-Fluid At Yellowstone Caldera Geothermal Region (1977) Isotopic Analysis-Fluid At Yellowstone Caldera Geothermal Region (1977) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis-Fluid At Yellowstone Caldera Geothermal Region (1977) Exploration Activity Details Location Yellowstone Caldera Geothermal Region Exploration Technique Isotopic Analysis-Fluid Activity Date 1977 Usefulness not indicated DOE-funding Unknown Exploration Basis Estimate deep reservoir temperature Notes The oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes have been tested. Methods are described to calculate the effects of boiling and dilution. The geothermometer, is applied to thermal systems of Yellowstone Park, Wyoming, Long Valley, California, and Raft River, Idaho to estimate deep reservoir temperatures

255

Concentrations and activity ratios of uranium isotopes in groundwater from Donana National Park, South of Spain  

SciTech Connect (OSTI)

The levels and distribution of natural radionuclides in groundwaters from the unconfined Almonte-Marismas aquifer, upon which Donana National Park is located, have been analysed. Most sampled points were multiple piezometers trying to study the vertical distribution of the hydrogeochemical characteristics in the aquifer. Temperature, pH, electrical conductivity, dissolved oxygen and redox potential were determined in the field. A large number of parameters, physico-chemical properties, major and minor ions, trace elements and natural radionuclides (U-isotopes, Th-isotopes, Ra-isotopes and {sup 210}Po), were also analysed. In the southern zone, where aeolian sands crop out, water composition is of the sodium chloride type, and the lower U-isotopes concentrations have been obtained. As water circulates through the aquifer, bicarbonate and calcium concentrations increase slightly, and higher radionuclides concentrations were measured. Finally, we have demonstrated that {sup 234}U/{sup 238}U activity ratios can be used as markers of the type of groundwater and bedrock, as it has been the case for old waters with marine origin confined by a marsh in the south-east part of aquifer.

Bolivar, J. P.; Olias, M.; Gonzalez-Garcia, F. [Department of Applied Physics, University of Huelva, Campus de El Carmen, 21071-Huelva (Spain); Garcia-Tenorio, R. [Department of Applied Physics II, University of Sevilla, ETSA Arquitectura, 41012-Sevilla (Spain)

2008-08-07T23:59:59.000Z

256

Oxygen Transport Membranes  

SciTech Connect (OSTI)

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

S. Bandopadhyay

2008-08-30T23:59:59.000Z

257

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

SciTech Connect (OSTI)

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.

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

258

ChemicalChemical StratigraphyStratigraphy Oxygen, Carbon, Strontium,  

E-Print Network [OSTI]

2/25/2009 1 ChemicalChemical StratigraphyStratigraphy Oxygen, Carbon, Strontium, Sulphur Isotopes Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department evolves over time, with the geological time line running from right to left in this graph. The increased

Miami, University of

259

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

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

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

260

ARM - Measurement - Isotope ratio  

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

govMeasurementsIsotope ratio govMeasurementsIsotope ratio ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Isotope ratio Ratio of stable isotope concentrations. Categories Atmospheric Carbon, Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments FLASK : Flask Samplers for Carbon Cycle Gases and Isotopes Field Campaign Instruments FLASK : Flask Samplers for Carbon Cycle Gases and Isotopes Datastreams FLASK : Flask Samplers for Carbon Cycle Gases and Isotopes

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Isotope Program Transportation | Department of Energy  

Office of Environmental Management (EM)

Isotope Program Transportation Isotope Program Transportation Isotope Program Transportation More Documents & Publications Nuclear Fuel Storage and Transportation Planning Project...

262

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

263

Direct Observation of the Oxygenated Species during Oxygen Reduction on a  

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

Direct Observation of the Oxygenated Species during Oxygen Reduction on a 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 spectroscopy identification and DFT simulations of oxygenated intermediates on a platinum fuel-cell cathode. The study shows that two types of hydroxyl intermediates (non-hydrated OH and hydrated OH) with distinct activities coexist on a fuel-cell cathode. The performance of polymer-electrolyte-membrane (PEM) fuel cells is limited by the reduction at the cathode of various oxygenated intermediates in the four-electron pathway of the oxygen reduction reaction. A research team led by SLAC scientists performed x-ray spectroscopy identification and DFT simulations of oxygenated intermediates on a platinum fuel-cell cathode

264

NASA [National Aeronautics and Space Administration] low power DIPS [Dynamic Isotope Power System] conceptual design study; Final report  

SciTech Connect (OSTI)

This report describes the conceptual design and integration of a low power (0.5 to 1.0 kWe) Dynamic Isotope Power System (DIPS) Low Power (LPD) with the Mariner Mark II (MMII) spacecraft for use on interplanetary and space exploration missions as an alternative to RTGs. A detailed MMII/LPD system description is provided that discusses, among other things, the design requirements, design point selection, system layout and spacecraft integration, mechanical design, electrical system design, interface assessments, reliability, and safety. Performance characteristics are given for the reference 500 We LPD using a peak cycle temperature of 1100 K. Parametrics are provided giving the LPD performance characteristics at power levels up to 1.0 kWe and peak cycle temperatures as high as 1300 K. A side-by-side comparison of the LPD performance with the RTG performance is provided. Finally, program plans, costs, and schedules are provided giving the overall plan for design, development, fabrication, qualification, and acceptance of the LPD system.

Otting, W.

1990-12-01T23:59:59.000Z

265

The global geochemical cycles of iron and calcium: using novel isotope systems to understand weathering, global mass budgets, natural reaction rates, and paleoclimate  

E-Print Network [OSTI]

. Traditional geochemical proxies utilize variations in the oxygen, carbon, and boron isotopic compositionThe global geochemical cycles of iron and calcium: using novel isotope systems to understand of California, Berkeley Spring 2005 #12;The global geochemical cycles of iron and calcium: using novel isotope

Fantle, Matthew

266

Novel Isotope Effects on the Pairing Pseudogap in High-$T_{c}$ Cuprates: Evidences for Polaronic Metal and Precursor BCS-Like Pairing of Large Polarons  

E-Print Network [OSTI]

We have studied the novel isotope effects on the pairing pseudogap in underdoped and optimally doped cuprates within the large-polaron model and two non-standard BCS-like approaches. We have shown that in the intermediate-coupling regime the precursor pairing of large polarons occurs at a mean-field temperature $T^{\\ast}>T_{c}$ and the near-absent, sizable and very large oxygen and copper isotope effects on $T^{\\ast}$ exist in cuprates with small and large Fermi surfaces. Our results for $T^{\\ast}$, isotope shifts and exponents in slightly underdoped and optimally doped cuprates are in quantitative agreement with existing experiments and explain the discrepancy between various experiments.

S. Dzhumanov; O. K. Ganiev; Sh. S. Djumanov

2010-06-15T23:59:59.000Z

267

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

S. Bandopadhyay; T. Nithyanantham

2006-12-31T23:59:59.000Z

268

Oxygen enriched fireflooding  

SciTech Connect (OSTI)

Both pure oxygen and enriched air have been considered in fireflooding for enhanced oil recovery. Laboratory and field testing have conclusively shown that oxygen is practical and cost effective for this application. For reservoirs that require a large volume of high pressure gas, oxygen is cheaper than air simply based on compression costs. Additional process benefits with oxygen include: Faster Oil Production; Lower Injection Pressure; Greater Well Spacing; Increased Carbon Dioxide Partial Pressure; Lower Gas-to-Oil Ratios; and Purer Produced Gas. These features provide a compelling case for oxygen, once the safety and materials compatibility issues are properly addressed.

Shahani, G.H.; Gunardson, H.H. [Air Products and Chemicals, Allentown, PA (United States)

1995-02-01T23:59:59.000Z

269

Reactor Physics Studies of Reduced-Tantaulum-Content Control and Safety Elements for the High Flux Isotope Reactor  

SciTech Connect (OSTI)

Some of the unirradiated High Flux Isotope Reactor (HFIR) control elements discharged during the late 1990s were observed to have cladding damage--local swelling or blistering. The cladding damage was limited to the tantalum/europium interface of the element and is thought to result from interaction of hydrogen and europium to form a compound of lower density than europium oxide, thus leading to a ''blistering'' of the control plate cladding. Reducing the tantalum loading in the control plates should help preclude this phenomena. The impact of the change to the control plates on the operation of the reactor was assessed. Regarding nominal, steady-state reactor operation, the impact of the change in the power distribution in the core due to reduced tantalum content was calculated and found to be insignificant. The magnitude and impact of the change in differential control element worth was calculated, and the differential worths of reduced tantalum elements vs the current elements from equivalent-burnup critical configurations were determined to be unchanged within the accuracy of the computational method and relevant experimental measurements. The location of the critical control elements symmetric positions for reduced tantalum elements was found to be 1/3 in. less withdrawn relative to existing control elements regardless of the value of fuel cycle burnup (time in the fuel cycle). The magnitude and impact of the change in the shutdown margin (integral rod worth) was assessed and found to be unchanged. Differential safety element worth values for the reduced-tantalum-content elements were calculated for postulated accident conditions and were found to be greater than values currently assumed in HFIR safety analyses.

Primm, R.T., III

2003-11-01T23:59:59.000Z

270

Mass-Independent Isotope Effects  

Science Journals Connector (OSTI)

Scientific interests: ESR and NMR spectroscopies, molecular magnets, mechanisms of chemical and biochemical reactions, spin physics and chemistry, isotopes and isotope effects in chemistry and biochemistry. ... Another mass-independent isotope effect was detected in 1983 as a deviation of isotopic distribution in reaction products from that which would be expected from the mass-dependent isotope effect. ... Later, Nomura et al.(92) have found isotopic 233U anomaly in the U4+U6+ exchange reaction; they noted that the isotope effect was correlated with isotope shifts in the atomic spectra of uranium isotopes. ...

Anatoly L. Buchachenko

2013-01-09T23:59:59.000Z

271

CERIUM OXIDE (CeO2) PROMOTED OXYGEN CARRIER DEVELOPMENT AND SCALE MODELING STUDY FOR CHEMICAL LOOPING COMBUSTION.  

E-Print Network [OSTI]

??According to IPCC reports, the greenhouse gas CO2 is responsible for global climate change. Studies show that CO2 concentration reached a level of 400 ppm (more)

Liu, Fang

2013-01-01T23:59:59.000Z

272

Hybrid isotope separation scheme  

DOE Patents [OSTI]

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.

Maya, J.

1991-06-18T23:59:59.000Z

273

Hybrid isotope separation scheme  

DOE Patents [OSTI]

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.

Maya, Jakob (Brookline, MA)

1991-01-01T23:59:59.000Z

274

Solar Activity Index: Validity Supported by Oxygen Isotope Dating  

Science Journals Connector (OSTI)

...CENTURIES OF CLIMATIC RECORD FROM CAMP CENTURY ON GREENLAND ICE SHEET, SCIENCE...sup> concentration in Greenland Camp Century ice core, correlation with solar...activity absolute age Arctic region Camp Century ice core dates general listing...

J. R. Bray

1970-05-01T23:59:59.000Z

275

Method for the Analysis of Oxygen Isotopic Composition of Soil  

E-Print Network [OSTI]

, including phosphorus (P) recycling by soil microorganisms, uptake by plants and P adsorption, precipitation.Twoagriculturalsoilsamples receiving reclaimed wastewater or fresh water were analyzed, and results indicate that all soil fractions, where rates of biological uptake and recycling through the biomass are relatively low, 18 OP (the ratio

Paytan, Adina

276

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

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

near-surface soils and sediments and interact strongly with dissolved phosphates via sorption, co-precipitation, mineral transformation and redox-cycling reactions. Iron oxide...

277

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...

278

Stable isotope enrichment  

SciTech Connect (OSTI)

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

Egle, Brian

2014-07-14T23:59:59.000Z

279

EMSL - isotopic ratio  

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

isotopic-ratio en Magnesium behavior and structural defects in Mg+ ion implanted silicon carbide. http:www.emsl.pnl.govemslwebpublicationsmagnesium-behavior-and-structural-def...

280

A survey of alternative oxygen production technologies  

Science Journals Connector (OSTI)

Utilization of the Martian atmosphere for the production of fuel and oxygen has been extensively studied. The baseline fuel production process is a Sabatier reactor which produces methane and water from carbon dioxide and hydrogen. The oxygen produced from the electrolysis of the water is only half of that needed for methane-based rocket propellant and additional oxygen is needed for breathing air fuel cells and other energy sources. Zirconia electrolysis cells for the direct reduction of CO 2 are being developed as an alternative means of producing oxygen but present many challenges for a large-scale oxygen production system. The very high operating temperatures and fragile nature of the cells coupled with fairly high operating voltages leave room for improvement. This paper will survey alternative oxygen production technologies present data on operating characteristics materials of construction and some preliminary laboratory results on attempts to implement each.

Dale E. Lueck; Clyde F. Parrish; William J. Buttner; Jan M. Surma

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Oxygen ion conducting materials  

DOE Patents [OSTI]

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.

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

2003-01-01T23:59:59.000Z

282

Chemical And Isotopic Investigation Of Warm Springs Associated With Normal  

Open Energy Info (EERE)

Isotopic Investigation Of Warm Springs Associated With Normal Isotopic Investigation Of Warm Springs Associated With Normal Faults In Utah Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Chemical And Isotopic Investigation Of Warm Springs Associated With Normal Faults In Utah Details Activities (3) Areas (1) Regions (0) Abstract: Thermal springs associated with normal faults in Utah have been analyzed for major cations and anions, and oxygen and hydrogen isotopes. Springs with measured temperatures averaging greater than 40°C are characterized by Na + K- and SO4 + Cl-rich waters containing 103 to 104 mg/l of dissolved solids. Lower temperature springs, averaging less than 40°C, are more enriched in Ca + Mg relative to Na + K. Chemical variations monitored through time in selected thermal springs are probably produced by

283

NIDC: Online Catalog of Isotope Products | Product List  

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

List List Please select an available isotope product from the lists below. If you would like an isotope product that is not listed, you can make a request by clicking here. Stable Isotope Products Radio-Isotope Products Antimony Argon (Alt) Barium Bromine Bromine (Alt) Cadmium Calcium Carbon (Alt) Cerium Chlorine Chlorine (Alt) Chromium Copper Dysprosium Erbium Europium Gadolinium Gallium Germanium Hafnium Helium (Alt) Indium Iridium Iron Krypton (Alt) Lanthanum Lead Lithium Lutetium Magnesium Mercury Molybdenum Neodymium Neon (Alt) Nickel Nitrogen (Alt) Osmium Oxygen (Alt) Palladium Platinum Potassium Rhenium Rubidium Ruthenium Samarium Selenium Silicon Silver Strontium Sulfur Sulfur (Alt) Tantalum Tellurium Thallium Tin Titanium Tungsten Vanadium Xenon (Alt) Ytterbium Zinc Zirconium Actinium-225 Aluminum-26 Americium-241

284

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

285

Isotopic Analysis At Dixie Valley Geothermal Field Area (Laney, 2005) |  

Open Energy Info (EERE)

Isotopic Analysis At Dixie Valley Geothermal Field Area (Laney, 2005) Isotopic Analysis At Dixie Valley Geothermal Field Area (Laney, 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Dixie Valley Geothermal Field Area (Laney, 2005) Exploration Activity Details Location Dixie Valley Geothermal Field Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness not indicated DOE-funding Unknown Notes Gas and Isotopes Geochemistry, Kennedy, van Soest and Shevenell. During FY04, we concentrated on two primary projects. The first was a detailed study of helium isotope systematics throughout Dixie Valley and the inter-relationship between the Dixie Valley geothermal reservoir and local hydrology. The second is the construction of a helium isotope "map" of the

286

Celebrating The Isotope  

Science Journals Connector (OSTI)

Celebrating The Isotope ... The notion of isotopes and the rest of Soddys lifetime body of work on radioactivity, the group displacement laws, the social responsibility of scientists, and the environment have had a profound effect on science and society. ...

GEORGE B. KAUFFMAN

2013-12-02T23:59:59.000Z

287

Isotope - based Quantum Information  

E-Print Network [OSTI]

This paper is brief review of three aspects of the isotope - based quantum information: computation, teleportation and cryptography. Our results demonstrate not only that entanglement exists in elementary excitation of isotope - mixed solids but also it can be used for quantum information processing.

Vladimir G. Plekhanov

2009-09-04T23:59:59.000Z

288

Laboratory studies of stratospheric bromine chemistry: Kinetics of the reactions of bromine monoxide with nitrogen dioxide and atomic oxygen  

SciTech Connect (OSTI)

A laser flash photolysis - long path absorption - technique has been employed to study the kinetics of the reaction BrO+NO2+M(k[sub 16]) yields products as a function of temperature (248-346 K), pressure (16-800 Torr), and buffer gas identity (N2, CF4). 351 nm photolysis of NO2/Br2/N2 mixtures generated BrO. The BrO decay in the presence of excess NO2 was followed by UV absorption at 338.3 nm. The reaction is in the falloff regime between third and second order over the entire range of conditions investigated. This is the first study where temperature dependent measurements of k[sub 16](P,T) have been reported at pressures greater than 12 Torr; hence, these results help constrain choices of k[sub 16](P,T) for use in modeling stratospheric BrO(x) chemistry. The kinetics of the important stratospheric reaction BrO+O(P-3)(k[sub 14]) yields Br+O2 in N2 buffer gas have been studied as a function of temperature (233-328 K) and pressure (25-150 Torr) using a novel dual laser flash photolysis/long path absorption/resonance fluorescence technique. 248 nm pulsed laser photolysis of Br2/O3/N2 mixtures produces O atoms in excess over Br2. After a delay sufficient for BrO to be generated, a 532 nm laser pulse photolysis a small fraction of the O3 to generate O(P-3). The decay of O(P-3) in the presence of an excess, known concentration of BrO, as determined by UV absorption at 338.3 nm and by numerical simulation, is then followed by time-resoved atomic resonance fluorescence spectroscopy. The experimental results have shown the reaction kinetics to be independent of pressure, to increase with decreasing temperature, and to be faster than suggested by the only previous (indirect) measurement. The resulting Anhenius expression for k[sub 14](T) is k[sub 14](T) = 1.64 x 10(exp -11) exp(263/T) cm(exp 3) molecule(exp-1)s(exp -1). The absolute accuracy of k[sub 14](T) at any temperature within the range studied is estimated to be +/- 25%.

Thorn, R.P.

1993-01-01T23:59:59.000Z

289

Oxygen concentration of Eu sub 1 Ba sub 2 Cu sub 3 O sub 7 minus x in vacuum: An atom probe study  

SciTech Connect (OSTI)

Atom Probe mass analysis, at 85 K, using a wide-angle instrument was used to measure the oxygen content and metallic stoichiometry of the near-surface region of the superconducting ceramic oxide Eu{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} ({ital x}{approx equal}0.1) after vacuum exposure at room temperature. Routine specimen preparation, handling, and field-ion imaging produced a specimen which had already lost oxygen such that its measured surface oxygen content corresponded to {ital x}=0.73 and the metallic stoichiometry of the surface was not the expected 1:2:3 but was enhanced in Ba and Eu. The specimen was subsequently exposed to vacuum for up to 80 h at room temperature and no additional loss of oxygen was detected. It was concluded that either (1) a stoichiometric low-oxygen surface also would not have lost oxygen or (2) the nonstoichiometric layer forms a barrier for subsequent oxygen loss.

Elswijk, H.B.; Melmed, A.J.; Camus, P.P. (National Institute of Standards and Technology, Surface Science Division, Gaithersburg, Maryland 20899 (US))

1989-12-18T23:59:59.000Z

290

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

2004-02-01T23:59:59.000Z

291

Matrix effect and partitioning of boron isotopes between immiscible Si-rich and B-rich liquids in the SiAlBCaNaO system: A SIMS study of glasses quenched from centrifuge experiments  

Science Journals Connector (OSTI)

The results of a study of isotopic fractionation of boron between silica-rich (LS) and borate-rich (LB) immiscible liquids in the system SiBAlCaNa are reported. Partitioning experiments were performed on glasses produced by quenching immiscible coexisting Si-rich and B-rich borosilicate melt pairs that had been equilibrated at high temperature and separated with the aid of a high temperature centrifuge furnace [Veksler, I.V., Dorfman, A.M., Dingwell, D.B., Zotov, N., 2002. Element partitioning between immiscible borosilicate liquids: a high-temperature centrifuge study. Geochim. Cosmochim. Acta 66, 26032614]. Here B/Si and 11B/10B ratios have been determined using secondary ion mass spectrometry (SIMS). The determinations encountered unexpectedly strong matrix effect (up to 12) due to contrasting chemical compositions of the immiscible melts. Employment of ?60 V high-voltage offset (not used during routine SIMS B isotope measurements) effectively eliminated the initially observed matrix effect. With this improved SIMS technique, we obtained the result that the coexisting quenched immiscible liquids have the same 11B/10B ratio within 1.2 (2?) analytical uncertainty. Thus little or no significant two-liquid fractionation of 10B and 11B isotopes was observed in the temperature range between 950 and 1350 C. This is despite the observation that significantly different proportions of trigonal vs. tetrahedrally coordinated B in these immiscible liquids have been determined by Raman spectroscopic analyses. The essential observations (i.e., a strong matrix effect and a lack of significant B isotope fractionation between the glasses) were both supported by independent thermal ionization mass spectrometry (TIMS) analyses of one selected centrifuged pair. Those glasses showed no difference in B isotopic composition within the quoted 2? analytical error of 1.0.

A.A. Gurenko; I.V. Veksler; A. Meixner; R. Thomas; A.M. Dorfman; D.B. Dingwell

2005-01-01T23:59:59.000Z

292

O and Pb isotopic analyses of uranium minerals by ion microprobe and UPb ages from the Cigar Lake deposit  

E-Print Network [OSTI]

O and Pb isotopic analyses of uranium minerals by ion microprobe and U­Pb ages from the Cigar Lake intergrown uranium minerals and oxygen isotopic analyes of uraninite from the unconformity-type Cigar Lake uranium deposit. Secondary uranium minerals intergrown with uraninite, such as coffinite, USiO4ÁnH2O

Fayek, Mostafa

293

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

E-Print Network [OSTI]

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

Polinkovsky, Mark E.; Polinkovsky, Mark E.

2012-01-01T23:59:59.000Z

294

Chemical accelerator studies of isotope effects on collision dynamics of ionmolecule reactions: Kr++HD  

E-Print Network [OSTI]

The reaction of Kr+ with HD has been studied as a function of relative collision energy over the range 0.083.1 eV (c.m.) by measuring integral reaction cross sections and the velocity vector distributions of product ions ...

Chivalak, S.; Hierl, Peter M.

1977-01-01T23:59:59.000Z

295

Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems  

SciTech Connect (OSTI)

A variety of physical processes affect solute concentrations within catchment waters. The isotopic compositions of the solutes can indicate which processes have determined the observed concentrations. These processes together constitute the physical history of the water. Many solutes in natural waters are derived from the interaction between the water and the rock and/or soil within the system - these are termed `lithogenic` solutes. The isotopic compositions of these solutes provide information regarding rock-water interactions. Many other solutes have their isotopic compositions determined both within and outside of the catchment - i.e., in addition to being derived from catchment rock and soil, they are solutes that are also transported into the catchment. Important members of this group include solutes that have isotopic compositions produced by atomic particle interactions with other nuclides. The source of the atomic particles can be cosmic radiation (producing `cosmogenic` nuclides in the atmosphere and land surface), anthropogenic nuclear reactions (producing `thermonuclear` nuclides), or radioactive and fission decay of naturally-occurring elements, principally {sup 238}U (producing `in-situ` lithogenic nuclides in the deep subsurface). Current language usage often combines all of the atomic particle-produced nuclides under the heading `cosmogenic nuclides`, and for simplicity we will often follow that usage here, although always indicating which variety is being discussed. This paper addresses the processes that affect the lithogenic and cosmogenic solute concentrations in catchment waters, and how the isotopic compositions of the solutes can be used in integrative ways to identify these processes, thereby revealing the physical history of the water within a catchment system. The concept of a `system` is important in catchment hydrology. A catchment is the smallest landscape unit that can both participate in all of the aspects of the hydrologic cycle and also be treated as a mostly closed system for mass balance considerations. It is the near closure of the system that permits well- constrained chemical mass balance calculations to be made. These calculations generally focus of lithogenic solutes, and therefore in our discussions of lithogenic nuclides in the paper, the concept of chemical mass balance in a nearly dosed system will play an important role. Examination of the isotopic compositions of solutes provides a better understanding of the variety of processes controlling mass balance. It is with this approach that we examined the variety of processes occurring within the catchment system, such as weathering and soil production, generation of stormflow and streamflow (hydrograph separation), movement of soil pore water, groundwater flow, and the overall processes involved with basinal water balance. In this paper, the term `nuclide` will be used when referring to a nuclear species that contains a particular number of protons and neutrons. The term is not specific to any element. The term `isotope` will be used to distinguish nuclear species of a given element (atoms with the same number of protons). That is to say, there are many nuclides in nature - for example, {sup 36}Cl, {sup 87}Sr, {sup 238}U; the element has four naturally-occurring isotopes - {sup 87}Sr, and {sup 88}Sr. This paper will first discuss the general principles that underlie the study of lithogenic and cosmogenic nuclides in hydrology, and provide references to some of the more important studies applying these principles and nuclides. We then turn in the second section to a discussion of their specific applications in catchment- scale systems. The final section of this paper discusses new directions in the application of lithogenic and cosmogenic nuclides to catchment hydrology, with some thoughts concerning possible applications that still remain unexplored.

Nimz, G. J., LLNL

1998-06-01T23:59:59.000Z

296

Plants making oxygen  

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

Plants making oxygen Plants making oxygen Name: Doug Status: N/A Age: N/A Location: N/A Country: N/A Date: Around 1993 Question: How many plants are needed to make enough oxygen for one person for one hour? We are experimenting with Anacharis plants. Replies: The problem can be solved when broken down into smaller questions: 1. How much oxygen does a person need in an hour? 2. How much oxygen does a plant produce in an hour? 3. Based on the above, how many plants will provide the oxygen needs of the person for the hour? Here is the solution to the first question: A resting, healthy adult on an average, cool day breathes in about 53 liters of oxygen per hour. An average, resting, health adult breathes in about 500 mL of air per breath. This is called the normal tidal volume. Now, 150 mL of this air will go to non- functioning areas of the lung, called the "dead space." The average breath rate for this average person is 12 breaths per minute. So, the amount of air breathed in by the person which is available for use is 12 x (500 mL -150 mL) = 4,200 mL/minute. Multiply by 60 to get 252,000 mL/hour. That is, every hour, the person will breathe in 252 L of air. Now, on an average, cool, clear day, only 21% of that air is oxygen. So, 21% of 252 L is 53 L. So, in an hour, the person breathes in about 53 L of oxygen.

297

Algae for Oxygen  

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

Algae for Oxygen Algae for Oxygen Name: Pam Burkardt Status: N/A Age: N/A Location: N/A Country: N/A Date: N/A Question: Hi, I am Pam Burkardt, a seventh grader at Fox Chapel School. I have a question on algae. I read somewhere that someday people might take bath tubs full of algae onto spaceships to provide oxygen for the crew. How much oxygen does algae give off, is this really possible? Replies: I think that most of the oxygen in the atmosphere comes in fact from one-celled plants in the oceans, like algae. They are likely to produce a lot of oxygen per unit weight because they don't have non-photosynthesizing bark, roots, branches, etc., nor (I think) a major dormant period like temperate-zone plants. The cost of space travel at present is dominated by the expense of heaving weight up into Earth orbit (it costs very little extra to send it to the Moon, for example, or Mars). For missions of short duration the weight of the compressed oxygen you need to carry is less than the weight of algae, water and extra plumbing you'd need to carry if you relied on algae to produce your oxygen. The important use of green plants would be in very long duration space flight (years) or permanent inhabitation of worlds like the Moon, where you need an unlimited supply of oxygen. Now if you want to fantasize, Venus' atmosphere is almost all carbon dioxide. Suppose you dropped a whole lot of specially gene-tailored one-celled plants into the atmosphere (not the surface, it's too hot). Why then they might eat up all the carbon dioxide and produce a breathable atmosphere. The "greenhouse effect" would go away, and Venus would become a nice habitable if tropical world only 50 million miles away.

298

lead-isotope age  

Science Journals Connector (OSTI)

lead-isotope age, lead-lead age [An age in years calculated from the ratio of lead-207 to lead-206, a by-product of the uranium-thorium-lead age method] ? Blei-Isotopen-Alter n

2014-08-01T23:59:59.000Z

299

Isotopic effect study in the LHCD and LHH experiments in hydrogen/deuterium plasmas of the FT-2 tokamak  

SciTech Connect (OSTI)

Results of comparative experimental studies of the efficiency of lower hybrid current drive (LHCD) and lower hybrid heating (LHH) in the FT-2 tokamak in hydrogen and deuterium plasmas are presented. In the new comparative experimental runs in deuterium/hydrogen plasmas suppression of the LHCD and beginning of the interaction of LH waves with ions is controlled by the plasma density rise. Role of parametric instabilities in CD switch-off is considered. In order to analyze the experimentally observed effect of LHCD the GRILL3D and FRTC codes has been used.

Lashkul, S. I.; Altukhov, A. B.; Gusakov, E. Z.; Dyachenko, V. V.; Esipov, L. A.; Irzak, M. A.; Kantor, M. Yu.; Kouprienko, D. V.; Saveliev, A. N. [A. F. Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg (Russian Federation); Shatalin, S. V. [St. Petersburg State Polytekhnical University, St. Petersburg (Russian Federation); Stepanov, A. Yu. [A.F. Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg (Russian Federation)

2014-02-12T23:59:59.000Z

300

Nuclear isotope thermometry  

Science Journals Connector (OSTI)

We discuss different aspects which might influence temperatures deduced from experimental isotopic yields in the multifragmentation process. It is shown that fluctuations due to the finite size of the system and distortions due to the decay of hot primary fragments conspire to blur the temperature determination in multifragmentation reactions. These facts suggest that caloric curves obtained through isotope thermometers, which were taken as evidence for a first-order phase transition in nuclear matter, should be investigated very carefully.

S. R. Souza, W. P. Tan, R. Donangelo, C. K. Gelbke, W. G. Lynch, and M. B. Tsang

2000-11-10T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

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)

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)

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

302

Bridge-bonded atomic oxygen on Pt(110)  

Science Journals Connector (OSTI)

We use hybrid density-functional theory (DFT) and scanning tunneling microscopy (STM) to study oxygen adsorption on the Pt(110) surface. In the STM images oxygen appear as bright protrusions on the ridges of the missing row reconstructed surface. DFT calculations of binding energies for atomic oxygen on a bridge site shows a clear preference over hollow sites.

E. Janin; H. von Schenck; M. Gthelid; U. O. Karlsson; M. Svensson

2000-05-15T23:59:59.000Z

303

Long Baseline Neutrino Experiment Target Material Radiation Damage Studies Using Energetic Protons of the Brookhaven Linear Isotope Production (BLIP) Facility  

E-Print Network [OSTI]

One of the future multi-MW accelerators is the LBNE Experiment where Fermilab aims to produce a beam of neutrinos with a 2.3 MW proton beam as part of a suite of experiments associated with Project X. Specifically, the LBNE Neutrino Beam Facility aims for a 2+ MW, 60 -120 GeV pulsed, high intensity proton beam produced in the Project X accelerator intercepted by a low Z solid target to facilitate the production of low energy neutrinos. The multi-MW level LBNE proton beam will be characterized by intensities of the order of 1.6 e+14 p/pulse, {\\sigma} radius of 1.5 -3.5 mm and a 9.8 microsecond pulse length. These parameters are expected to push many target materials to their limit thus making the target design very challenging. To address a host of critical design issues revealed by recent high intensity beam on target experience a series of experimental studies on radiation damage and thermal shock response conducted at BNL focusing on low-Z materials have been undertaken with the latest one focusing on LBNE.

Simos, N; Hurh, P; Mokhov, N; Kotsina, Z

2014-01-01T23:59:59.000Z

304

Isotopes Environ. Health Stud., 2003, Vol. 39(1), pp. 4152 TREE SPECIES OF THE CENTRAL AMAZON AND  

E-Print Network [OSTI]

AND SOIL MOISTURE ALTER STABLE ISOTOPE COMPOSITION OF NITROGEN AND OXYGEN IN NITROUS OXIDE EVOLVED FROM SB RAS, Krasnoyarsk, Russia; b Department of Biological Sciences and Merriam-Powell Center; Oxygen 18; Tree species; Tropical soils INTRODUCTION The increase in the atmospheric concentration

Lehmann, Johannes

305

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

S. Bandopadhyay; N. Nagabhushana

2003-08-07T23:59:59.000Z

306

Active oxygen species and mechanism for low-temperature CO oxidation reaction on a TiO{sub 2}-supported Au catalyst prepared from Au(PPh{sub 3})(NO{sub 3}) and as-precipitated titanium hydroxide  

SciTech Connect (OSTI)

The active oxygen species and mechanism for catalytic CO oxidation with O{sub 2} on a highly active TiO{sub 2}-supported Au catalyst (denoted as Au/Ti(OH){sub 4}{sup *}), which was prepared by supporting a Au-phophine complex on as-precipitated wet titanium hydroxide followed by calcination at 673 K, have been studied by means of oxygen isotope exchange, O{sub 2} temperature-programmed desorption (O{sub 2} TPD), electron spin resonance (ESR), and Fourier-transformed infrared spectroscopy (FT-IR). Surface lattice oxygen atoms on the Au/Ti(OH){sub 4}{sup *} catalyst were inactive for oxygen exchange with O{sub 2} and CO and also for CO oxidation at room temperature. The surface lattice oxygen atoms were exchanged only with the oxygen atoms of CO{sub 2}, probably via carbonates. O{sub 2} did not dissociate to atomic oxygen on the catalyst. The catalyst showed a paramagnetic signal at g = 2.002 due to unpaired electrons trapped at oxygen vacancies mainly at the surface. O{sub 2} adsorbed on the oxygen vacancies to form superoxide O{sub 2}{sup {minus}} with g{sub 1} = 2.020, g{sub 2} = 2.010, and g{sub 3} = 2.005, which are characteristic of O{sub 2}{sup {minus}} with an angular arrangement. Upon CO exposure, all the adsorbed oxygen species disappeared. The mechanism for the catalytic CO oxidation on the active Au/Ti(OH){sub 4}{sup *} catalyst is discussed in detail and compared with mechanisms reported previously.

Liu, H.; Kozlov, A.I.; Kozlova, A.P.; Shido, Takafumi; Asakura, Kiyotaka; Iwasawa, Yasuhiro [Univ. of Tokyo (Japan)] [Univ. of Tokyo (Japan)

1999-07-25T23:59:59.000Z

307

Isotopic Analysis At Clear Lake Area (Thompson, Et Al., 1992) | Open Energy  

Open Energy Info (EERE)

Clear Lake Area (Thompson, Et Al., 1992) Clear Lake Area (Thompson, Et Al., 1992) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Clear Lake Area (Thompson, Et Al., 1992) Exploration Activity Details Location Clear Lake Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful DOE-funding Unknown Notes Deuterium and oxygen- 18 values of the thermal waters indicate that they recharged locally and became K271enriched in oxygen-18 by exchange with rock. The isotopic composition of the waters indicates that they are of meteoric origin. A plot of deuterium versus chloride indicates that as the chloride concentration increases, the deuterium composition remains essentially constant. A plot of oxygen-18 versus chloride shows that the

308

Radioactive Kr Isotopes  

Science Journals Connector (OSTI)

A radioactive isotope of 1.1-hour half-life has been produced in krypton by alpha-particle bombardment of Se74, enriched electromagnetically from 0.9 percent to 14.1 percent. Assignment of the isotope is made to Kr77. Aluminum absorption measurements indicate a positron end point of 1.7 Mev. In addition to annihilation radiation, gamma-rays and K-capture have been observed. The ratio of K-capture to positron emission from the Se74(?,n) reaction is computed as 2.6. The krypton 1.42-day isotope has been produced by an ?,n reaction on electromagnetically enriched Se76. The isotope is located as Kr79 and its half-life confirmed. A positron end point of 1.0 Mev is determined by aluminum absorption measurements. In addition to annihilation radiation, gamma-rays and K-capture have been observed. The ratio of K-capture to positron emission from the Se76(?,n) reaction is computed to be 50. The cross-section ratio for formation of Kr77 compared to Kr79 by alpha-particle bombardment of selenium is computed as 1.4. The 4.6-hour Kr85 isotope has been produced by a Se(?,n) reaction.

L. L. Woodward; D. A. Mccown; M. L. Pool

1948-10-01T23:59:59.000Z

309

Multicycle study on chemical-looping combustion of simulated coal gas with a CaSO{sub 4} oxygen carrier in a fluidized bed reactor  

SciTech Connect (OSTI)

The cyclic test of a CaSO{sub 4}-based oxygen carrier (natural anhydrite) in alternating reducing simulated coal gas and oxidizing conditions was performed at 950{degree}C in a fluidized bed reactor at atmospheric pressure. A high concentration of CO{sub 2} was obtained in the reduction. The H{sub 2} and CO conversions and CO{sub 2} yield increased initially and final decreased significantly. The release of SO{sub 2} and H{sub 2}S during the cyclic test was found to be responsible for the decrease of reactivity of a CaSO{sub 4} oxygen carrier. The oxygen carrier conversion after the reduction reaction decreased gradually in the cyclic test. Through the comparison of mass-based reaction rates as a function of mass conversion at typical cycles, it was also evident that the reactivity of a CaSO{sub 4} oxygen carrier increased for the initial cycles but finally decreased after around 15 cycles. X-ray diffraction analysis revealed that the presence and intensity of the reduction sulfur species was in accordance with the results of gas conversion. The content of CaO was higher than expected, suggesting the formation of SO{sub 2} and H{sub 2}S during the cycles. Surface morphology analysis demonstrates that the natural anhydrite particle surface varied from impervious to porous after the cyclic test. It was also observed that the small grains on the surface of the oxygen carrier sintered in the cyclic tests. Energy-dispersive spectrum analysis also demonstrated the decrease of oxygen intensity after reduction, and CaO became the main component after the 20th oxidation. Pore structure analysis suggested that the particles agglomerated or sintered in the cyclic tests. The possible method for sulfur mitigation is proposed. Finally, some basic consideration on the design criteria of a CLC system for solid fuels using a CaSO{sub 4} oxygen carrier is discussed by the references and provides direction for future work. 49 refs., 10 figs., 5 tabs.

Qilei Song; Rui Xiao; Zhongyi Deng; Wenguang Zheng; Laihong Shen; Jun Xiao [Southeast University, Nanjing (China). Thermoenergy Engineering Research Institute

2008-11-15T23:59:59.000Z

310

Solar energy: Hydrogen and oxygen  

Science Journals Connector (OSTI)

Solar energy: Hydrogen and oxygen ... Demonstrating the electrolysis of water with solar energy. ...

John J. Farrell

1982-01-01T23:59:59.000Z

311

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

E-Print Network [OSTI]

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.

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

2006-06-07T23:59:59.000Z

312

Optical oxygen concentration monitor  

DOE Patents [OSTI]

A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen`s A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2,000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest. 4 figs.

Kebabian, P.

1997-07-22T23:59:59.000Z

313

Isotope separation apparatus  

DOE Patents [OSTI]

Isotope separation apparatus consisting of a plurality of cells disposed adjacent to each other in an evacuated container. A common magnetic field is established extending through all of the cells. A source of energetic electrons at one end of the container generates electrons which pass through the cells along the magnetic field lines. Each cell includes an array of collector plates arranged in parallel or in tandem within a common magnetic field. Sets of collector plates are disposed adjacent to each other in each cell. Means are provided for differentially energizing ions of a desired isotope by applying energy at the cyclotron resonant frequency of the desired isotope. As a result, the energized desired ions are preferentially collected by the collector plates.

Arnush, Donald (Rancho Palos Verdes, CA); MacKenzie, Kenneth R. (Pacific Palisades, CA); Wuerker, Ralph F. (Palos Verdes Estates, CA)

1980-01-01T23:59:59.000Z

314

GENERATION OF RADIOXENON ISOTOPES  

SciTech Connect (OSTI)

With the continued population of the International Monitoring System (IMS) network and the certification of radioxenon laboratory systems it has become necessary to calibrate and test these systems using as many of the radioxenon isotopes as possible. Several very promising techniques have been explored recently that allow for convenient production of Xe-133, Xe-131m, the short-lived isotope Xe-135, and even the difficult to obtain Xe-133m. IMS national and international laboratories have traditionally obtained Xe-133 from medical isotope suppliers. The activity of these medical dose samples is extremely high (~ 740 MBq) and requires very careful fume hood work to dilute down to appropriate levels (~ 10 Bq). By waiting for 10 or more half-lives it is possible to reduce the handling regimen considerably, while also obtaining a strong Xe-131m signature due to its longer half-life (11.9 days). The short-lived isotope Xe-135 (9.14 hrs) and the longer lived parent nuclide Xe-133m (2.2 day half-life) are never present in these samples. To obtain these isotopes another source or technique is required. This paper will discuss the two techniques developed and implemented at Pacific Northwest National Lab (PNNL) and show the results obtained from each technique. The first is an in-house method that allows for on demand production of two of these isotopes, Xe-133 and Xe-135, using HEU and a modest flux neutron source. The second method uses a research reactor at the Pullman campus of Washington State University to produce Xe-133, Xe-133m and Xe-135.

McIntyre, Justin I.; Pratt, Sharon L.; Bowyer, Ted W.; Cooper, Matthew W.; Hayes, James C.; Heimbigner, Tom R.; Hubbard, Charles W.; Miley, Harry S.; Ripplinger, Mike D.

2008-09-23T23:59:59.000Z

315

Oxygen in Underwater Cave  

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

Oxygen in Underwater Cave Oxygen in Underwater Cave Name: Natalie Status: student Grade: 9-12 Location: HI Country: USA Date: Spring 2011 Question: Is it possible for there to be free oxygen in an underwater cave? If it is, then how does it work? Replies: Yes it is possible as I have personally experienced. If the cave roof rises to a level above the water, air dissolved in the water will slowly out gas until the water is at the same level at all places. A pocket of breathable air will form. In many caves the roof dips below water level in one place but it above it on both sides. Think of a U shaped tube where the bottom of the U is blocked by water. This is called a siphon and I have passed through many of these to find breathable air on the other side. R. W. "Bob" Avakian Oklahoma State Univ. Inst. of Technology

316

Isotope Effect of Mercury Diffusion in Air  

Science Journals Connector (OSTI)

Isotope fractionation describes the separation of a reservoir with one isotope composition into fractions with different isotope compositions due to small isotopic differences in equilibrium partitioning, rates of mass transfer, or rates of transformation. ... (29) ?202Hg is the value most frequently used to examine mass dependent fractionation of mercury isotopes as 202Hg is the heaviest mercury isotope without significant isobaric interferences. ...

Paul G. Koster van Groos; Bradley K. Esser; Ross W. Williams; James R. Hunt

2013-12-23T23:59:59.000Z

317

Electronic Structure of the Mn(4)Ca Cluster in the Oxygen-Evolving Complex of Photosystem Ii Studied By Resonant Inelastic X-Ray Scattering  

SciTech Connect (OSTI)

Oxygen-evolving complex (Mn{sub 4}Ca cluster) of Photosystem II cycles through five intermediate states (S{sub i}-states, i=0--4) before a molecule of dioxygen is released. During the S-state transitions, electrons are extracted from the OEC, either from Mn or alternatively from a Mn ligand. The oxidation state of Mn is widely accepted as Mn{sub 4}(III{sub 2},IV{sub 2}) and Mn{sub 4}(III,IV{sub 3}) for S{sub 1} and S{sub 2} states, while it is still controversial for the S{sub 0} and S{sub 3} states. We used resonant inelastic X-ray scattering (RIXS) to study the electronic structure of Mn{sub 4}Ca complex in the OEC. The RIXS data yield two-dimensional plots that provide a significant advantage by obtaining both K-edge pre-edge and L-edge-like spectra simultaneously. The second energy dimension separates the pre-edge (1s to 3d) transitions from the main K-edge (1s to 4p), and thus more precise analysis is possible. The 1s2p RIXS final state electron configuration along the energy transfer axis is identical to conventional L-edge absorption spectroscopy and the RIXS spectra are therefore sensitive to the metal spin state. We have collected data from PS II samples in the each of the S-states and compared them with data from various inorganic Mn complexes. The spectral changes in the Mn 1s2p{sub 3/2} RIXS spectra between the S-states are small compared to those of the oxides of Mn and coordination complexes. The results indicate strong covalency for the electronic configuration in the OEC, and we conclude that the electron is transferred from a strongly delocalized orbital, compared to those in Mn oxides or coordination complexes. The magnitude for the S{sub 0} to S{sub 1}, and S{sub 1} to S{sub 2} transitions is twice as large as that during the S{sub 2} to S{sub 3} transition, indicating that the electron for this transition is extracted from a highly delocalized orbital with little change in charge density at the Mn atoms. The RIXS spectra of S{sub 0} and S{sub 3} states also showed characteristic features which were not clear from the K-edge spectroscopy.

Yano, J.; Pushkar, Y.; Messinger, J.; Bergmann, U.; Glatzel, P.; Yachandra, V.K.

2009-06-04T23:59:59.000Z

318

Isotopic Analysis-Fluid At Raft River Geothermal Area (1977) | Open Energy  

Open Energy Info (EERE)

Isotopic Analysis-Fluid At Raft River Geothermal Area (1977) Isotopic Analysis-Fluid At Raft River Geothermal Area (1977) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis-Fluid At Raft River Geothermal Area (1977) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1977 Usefulness not indicated DOE-funding Unknown Exploration Basis Estimate deep reservoir temperature Notes The oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes have been tested. Methods are described to calculate the effects of boiling and dilution. The geothermometer, is applied to thermal systems of Yellowstone Park, Wyoming, Long Valley, California, and Raft River, Idaho to estimate deep reservoir temperatures

319

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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.

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

320

Boron and lead isotope signatures of subduction-zone mlange formation: Hybridization and fractionation along the  

E-Print Network [OSTI]

Boron and lead isotope signatures of subduction-zone mélange formation: Hybridization Angeles, CA, 90095, USA Accepted 9 January 2007 Editor: S.L. Goldstein Abstract The B and Pb isotope studies have directly addressed potential fractionation of B isotopes and U­Th­Pb by analysis of high

Bebout, Gray E.

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
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321

Oxygen Coverage Dependence of NO Oxidation on Pt(111). | EMSL  

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

Dependence of NO Oxidation on Pt(111). Abstract: The interaction of NO with adsorbed atomic oxygen on Pt(111) was studied with temperature programmed desorption (TPD),...

322

Oxygen-nutrient relationships in the Pacific Ocean  

Science Journals Connector (OSTI)

Aug 18, 1972 ... In the northeastern Pacific Ocean the oxygen-phosphate ... different stations in the Pacific and Indian Oceans to study their water masses.

2000-01-04T23:59:59.000Z

323

Optical oxygen concentration monitor  

DOE Patents [OSTI]

A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen's A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest.

Kebabian, Paul (Acton, MA)

1997-01-01T23:59:59.000Z

324

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)

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.

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 Universitt Darmstadt, 64287 Darmstadt (Germany); Schroeder, Thomas [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Brandenburgische Technische Universitt, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

2014-05-28T23:59:59.000Z

325

Isotopic substitution in a model polaronic system  

Science Journals Connector (OSTI)

The effect of isotopic substitution in the excitation spectrum of a model polaronic system is presented. To study this effect we use a three-site many-body Hamiltonian, with two phonon modes, which includes electronic correlations and electron-phonon interactions. Under isotopic substitution, the shift of the lowest excitation energy changes sign for intermediate electron-phonon coupling, coinciding with the onset of polaronic behavior. This manifests as a strong change of the dynamics of polaron tunneling, a behavior opposite to that found in purely phonon excitations. Additionally, a small change in the static polaronic distortion appears under isotopic substitution. This change in the local structure has opposite signs for low and intermediate electron-phonon coupling compared to that found in the strong-coupling limit.

J. Mustre de Leon; R. de Coss; A. R. Bishop; S. A. Trugman

1999-04-01T23:59:59.000Z

326

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

E-Print Network [OSTI]

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

Myers, Tom

327

Underground coal gasification using oxygen and steam  

SciTech Connect (OSTI)

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.

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

2009-07-01T23:59:59.000Z

328

Interactions of oxygen with Zr(0001)  

SciTech Connect (OSTI)

Interaction of oxygen with Zr(0001) have been studied using low energy electron diffraction (LEED), work function ([Delta][phi]), static and dynamic secondary ion mass spectrometry (SSIMS, DSIMS), thermal desorption spectroscopy (TDS), Auger electron spectroscopy (AES) and nuclear reaction analysis (NRA). The initial sticking coefficient of oxygen is close to unity up to [approximately]0.75 ML at 90, 293 and 473 K. Oxygen chemisorption is disordered at room temperature and below. Heating the disordered surface to [approximately]473 K causes all oxygen to move to subsurface sites. A (1x2) ordered oxygen underlayer is formed consisting of three rotated domains of (1x2) superstructure with the oxygen atoms located between the first and second planes of zirconium atoms. This structure is stable up to about 573 K, above which temperature oxygen diffuses into the bulk. AES measurements employing oxide and metal signals were used to model the growth of oxide which was found to be temperature dependent. Both NRA and AES indicate linear oxygen uptake kinetics at 90 K with abrupt passivation as the limiting thickness is reached. SSIMS ion yield data taken during the oxidation of Zr(0001) at 90, 293 and 473 K was interpretable in the context of the oxygen coverage. Dissolution into the bulk of the saturated oxide layer grown at 90 K appears to occur by an island-type mechanism rather than layer-by-layer dissolution from the oxide-metal interface. Large [Delta][phi] changes that occur upon oxidation at 90 K and temperature ramping of the saturated oxide to 300 K are attributable to reversible molecular oxygen adsorption on the oxide. The diffusion of oxygen normal to the [0001] plane of zirconium has been measured by AES: D[sub 0] = (4.14.[+-]1.92) x 10[sup [minus]2] cm[sup [minus]2] s[sup [minus]1] and E[sub a]= 199.1 [+-]2.6 kJ mol[sup [minus]1]. The fundamental vibrational frequency for the [alpha]-Zr lattice was calculated to be (6.3 [+-] 2.9) x 10[sup 13]s[sup [minus]1].

Flinn, B.J.

1992-01-01T23:59:59.000Z

329

Establishing the LaMnO3 Surface Phase Diagram in an Oxygen Environment: An ab Initio Kinetic Monte Carlo Simulation Study  

Science Journals Connector (OSTI)

Following the Sabatier principle, we note that phase boundaries on the surface phase diagrams are expected to correlate well with the high catalytic activity regimes on the pressure and temperature scales. ... The excess oxygen molecules not chemisorbed on the surface were washed out by helium fed to the reactor at a 50 cm3 min1 flow rate. ... After comparing the activities of the LSCF catalysts for the catalytic combustion of toluene, it was found that the substitution by little amts. of Sr and Fe improved the activity of LaCoO3. ...

G. Pilania; P.-X. Gao; R. Ramprasad

2012-12-01T23:59:59.000Z

330

High pressure oxygen furnace  

DOE Patents [OSTI]

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.

Morris, D.E.

1992-07-14T23:59:59.000Z

331

High pressure oxygen furnace  

DOE Patents [OSTI]

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.

Morris, Donald E. (Kensington, CA)

1992-01-01T23:59:59.000Z

332

Oxygen abundances in the most oxygen-rich spiral galaxies  

E-Print Network [OSTI]

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.

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

2006-01-06T23:59:59.000Z

333

Oxygen Concentration Microgradients for Cell Culture  

E-Print Network [OSTI]

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

Park, Jaehyun

2010-01-01T23:59:59.000Z

334

The mid-Cretaceous water bearer: isotope mass balance quantication of the Albian hydrologic cycle  

E-Print Network [OSTI]

. Witzke a;b;c a Department of Geoscience, University of Iowa, Iowa City, IA 52242-1379, USA b Center of the equable `greenhouse' Albian Stage in the KWIB. The mass balance model tracks the evolving isotopic conditions. ? 2002 Elsevier Science B.V. All rights reserved. Keywords: sphaerosiderites; Cretaceous; oxygen

González, Luis A.

335

Surface-cycling of rhenium and its isotopes  

E-Print Network [OSTI]

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. ...

Miller, Christian Alexander

2009-01-01T23:59:59.000Z

336

Mantle Helium And Carbon Isotopes In Separation Creek Geothermal...  

Open Energy Info (EERE)

we present the helium and carbon isotope results from the initial study of a fluid chemistry-monitoring program started in the summer of 2001 near the South Sister volcano in...

337

On the solar nickel and oxygen abundances  

E-Print Network [OSTI]

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.

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

2008-11-05T23:59:59.000Z

338

Comparisons between stable isotope tr  

Science Journals Connector (OSTI)

Nitrogen spiraling in streams: Comparisons between stable isotope tracer and nutrient addition experiments. AbstractA common method to quantify stream.

2007-05-31T23:59:59.000Z

339

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

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

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

2005-05-01T23:59:59.000Z

340

Hydrogen isotope fractionation in algae: III. Theoretical interpretations  

Science Journals Connector (OSTI)

Abstract Hydrogen isotope measurements of lipid biomarkers preserved in sediments are most commonly interpreted as qualitative, rather than quantitative indicators of paleoprecipitation owing to an imperfect knowledge of all factors controlling the isotopic fractionation occurring during biosynthesis. Here, we first offer a brief review of appropriate procedures for preparing enriched isotope substrates for use in tracer studies and outline the approximate ?D threshold at which this transition occurs. We then present new interpretations to explain deviations from common stable isotope effects observed in our previous culture experiments and other studies. We draw particular attention to the disagreement between intercept and slope for productsubstrate relationships from those predicted for isotope systems, even when R2 values are high, and attribute it to kinetic isotope fractionation. We demonstrate that reconstructing paleoenvironmental water ?D values by simply adding a ? to measured biomarkers ?D values will result in a bias toward deuterium enriched values. This applies even to implicit reconstructions in the form of qualitative interpretations of measured lipid ?D values as indicators of past hydroclimate. We therefore recommend reconstructing water ?D values from lipid ?D values using fractionation factor (?). We also discuss the apparently contradictory increase in D/H fractionation observed at elevated temperature and suggest that this may be the result of the unique wave-particle duality of hydrogen isotopes, which permits isotopologues to avoid surmounting the activation energy barrier that is necessary in traditional kinetic reactions.

Zhaohui Zhang; Daniel B. Nelson; Julian P. Sachs

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

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...

342

Isotopic Composition of Solar Wind Calcium: First in Situ Measurement by CELIAS/MTOF on Board SOHO  

E-Print Network [OSTI]

We present first results on the Ca isotopic abundances derived from the high resolution Mass Time-of-Flight (MTOF) spectrometer of the charge, element, and isotope analysis system (CELIAS) experiment on board the Solar and Heliospheric Observatory (SOHO). We obtain isotopic ratios 40Ca/42Ca = (128+-47) and 40Ca/44Ca = (50+-8), consistent with terrestrial values. This is the first in situ determination of the solar wind calcium isotopic composition and is important for studies of stellar modeling and solar system formation since the present-day solar Ca isotopic abundances are unchanged from their original isotopic composition in the solar nebula.

R. Kallenbach; F. M. Ipavich; P. Bochsler; S. Hefti; P. Wurz; M. R. Aellig; A. B. Galvin; J. Geiss; F. Gliem; G. Gloeckler; H. Grunwaldt; M. Hilchenbach; D. Hovestadt; B. Klecker

1998-02-07T23:59:59.000Z

343

Composite oxygen transport membrane  

DOE Patents [OSTI]

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.

Christie, Gervase Maxwell; Lane, Jonathan A.

2014-08-05T23:59:59.000Z

344

OXYGEN ABUNDANCES IN CEPHEIDS  

SciTech Connect (OSTI)

Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTE analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.

Luck, R. E.; Andrievsky, S. M. [Department of Astronomy, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7215 (United States); Korotin, S. N.; Kovtyukh, V. V., E-mail: luck@fafnir.astr.cwru.edu, E-mail: serkor@skyline.od.ua, E-mail: val@deneb1.odessa.ua, E-mail: scan@deneb1.odessa.ua [Department of Astronomy and Astronomical Observatory, Odessa National University, Isaac Newton Institute of Chile, Odessa Branch, Shevchenko Park, 65014 Odessa (Ukraine)

2013-07-01T23:59:59.000Z

345

Oxygen Atoms Display Novel Behavior on Common Catalyst  

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

11, 2008 11, 2008 Oxygen Atoms Display Novel Behavior on Common Catalyst Like waltzing dancers, the two atoms of an oxygen molecule usually behave identically when they separate on the surface of a catalyst. However, new research from the Environmental Molecular Sciences Laboratory reveals that on a particular catalyst, the oxygen atoms act like a couple dancing the tango: one oxygen atom plants itself while the other shimmies away, probably with energy partially stolen from the stationary one. Scientists from EMSL and Pacific Northwest National Laboratory discovered this unanticipated behavior while studying how oxygen interacts with reduced titanium oxide, a popular catalyst and a model oxide. Their research began with a slice of titanium oxide crystal, oriented so that titanium and oxygen

346

Isotope effect in the presence of a pseudogap  

Science Journals Connector (OSTI)

We investigate the question of whether the unusual doping dependence of the isotope exponent observed in underdoped high-Tc superconductors might be related to another unusual phenomenon observed in these systems: the pseudogap phenomenon. Within different approximations we study the influence of a phenomenological pseudogap on the isotope exponent and find that it generally strongly increases the isotope exponent, in qualitative agreement with experiments on underdoped high-Tc compounds. This result is stable against strong-coupling self-energy corrections and also holds for recently proposed spin-fluctuation exchange models, if a weak additional electron-phonon coupling is considered.

T. Dahm

2000-03-01T23:59:59.000Z

347

Oxygen control in makeup water for PWRs  

SciTech Connect (OSTI)

This study describes the oxygen control program and improvements to the make-up water system components of PWR nuclear plants with the ultimate goal of reducing corrosion related problems in the steam generators and other secondary system components. A PWR plant that has a vacuum degasifier has been selected to establish the basis for the program. Following the investigation of the make-up water system components, the report presents instrumentation developed for the program. Recommendations are provided for improvements to the various make-up water system components to lower the dissolved oxygen levels. 5 refs., 23 figs., 3 tabs.

Silaghy, F. (Burns and Roe, Inc., Oradell, NJ (USA))

1990-08-01T23:59:59.000Z

348

Leading chiral three-nucleon forces along isotope chains in the calcium region  

E-Print Network [OSTI]

Three-nucleon forces (3NFs), and in particular terms of the Fujita-Miyazawa type, strongly influence the structure of neutron-rich exotic isotopes. Ab-initio calculations have shown that chiral two- and three-nucleon interactions correctly reproduce binding energy systematics and neutron driplines of oxygen and nearby isotopes. Exploiting the novel self-consistent Gorkov-Green's function approach, we present the first investigation of Ar, K, Ca, Sc and Ti isotopic chains. Leading chiral 3N interactions are mandatory to reproduce the trend of binding energies throughout these chains and to obtain a good description of two-neutron separation energies. At the same time, nuclei in this mass region are systematically overbound by about 40 MeV and the $N=20$ magic gap is significantly overestimated. We conclude that ab-initio many-body calculations of mid-mass isotopic chains challenge modern theories of elementary nuclear interactions.

V. Som; A. Cipollone; C. Barbieri; P. Navrtil; T. Duguet

2013-12-07T23:59:59.000Z

349

Isotopic Analysis- Fluid | Open Energy Information  

Open Energy Info (EERE)

Isotopic Analysis- Fluid Isotopic Analysis- Fluid Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Isotopic Analysis- Fluid Details Activities (61) Areas (32) Regions (6) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Fluid Lab Analysis Parent Exploration Technique: Fluid Lab Analysis Information Provided by Technique Lithology: Water rock interaction Stratigraphic/Structural: Hydrological: Origin of hydrothermal fluids; Mixing of hydrothermal fluids Thermal: Isotopic ratios can be used to characterize and locate subsurface thermal anomalies. Dictionary.png Isotopic Analysis- Fluid: Isotopes are atoms of the same element that have different numbers of neutrons. An isotopic analysis looks at a particular isotopic element(s) in

350

Isotope Development & Production | Nuclear Science | ORNL  

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

of the "Calutrons" (electromagnetic enrichment devices) were converted by ORNL to the separation and enrichment of stable isotopes and some actinide isotopes. Until 1998 when...

351

Isotope shifts of multipole lines of Pb I and Pb II  

Science Journals Connector (OSTI)

Studies of isotope shifts of three multipole lines between levels of the ground configuration 6s26p2 of Pb I, i.e.:...

Wasowicz, Tomasz Jaroslaw; Werbowy, Slawomir; Kwela, Jerzy; Drozdowski, Ryszard

2010-01-01T23:59:59.000Z

352

E-Print Network 3.0 - apport des isotopes Sample Search Results  

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

Novel, J.P., Ravello, M., Dray, M., and Zuppi, G.M., 1996, Apport des analyses... ISOTOPE COMPOSITION OF PRECIPITATION AND SURFACE WATERS: CONSIDERATIONS FOR STUDIES OF...

353

Tunneling of coupled methyl groups in lithium acetate: The isotope effect  

Science Journals Connector (OSTI)

We studied by high resolution inelastic neutron scattering the isotope effect of tunneling of coupled methyl groups in lithium acetate dihydrate (LIAC). Fully protonated, fully...

A. Heidemann; H. Friedrich; E. Gnther

1989-01-01T23:59:59.000Z

354

Maser and Infrared Studies of Oxygen-Rich Late/Post-AGB Stars and Water Fountains: Development of a New Identification Method  

E-Print Network [OSTI]

We explored an efficient method to identify evolved stars with oxygen-rich envelopes in the late AGB or post-AGB phase of stellar evolution, which include a rare class of objects - the "water fountains". Our method considers the OH and H2O maser spectra, the near infrared Q-parameters (these are colour indices accounting for the effect of extinction), and far-infrared AKARI colours. Here we first present the results of a new survey on OH and H2O masers. There were 108 colour-selected objects: 53 of them were observed in the three OH maser lines (1612, 1665, and 1667 MHz), with 24 detections (16 new for 1612 MHz); and 106 of them were observed in the H2O maser line (22 GHz) with 24 detections (12 new). We identify a new potential water fountain source, IRAS19356+0754, with large velocity coverages of both OH and H2O maser emission. In addition, several objects with high velocity OH maser emission are reported for the first time. The Q-parameters as well as the infrared [09]-[18] and [18]-[65] AKARI colours of ...

Yung, Bosco; Henkel, Christian

2014-01-01T23:59:59.000Z

355

Theoretical study on OH{sup ?} site and electronic spin state of oxygen-evolving complex in photosystem II at the dark S{sub 1} state  

SciTech Connect (OSTI)

Possible protonation and electronic-spin states of oxygen-evolving complex (OEC) in photosystem II have been investigated by using QM(DFT-UB3LYP)/MM(Amber) calculation, in order to elucidate which OEC state satisfies the known experimental results at the dark stable state (S{sub 1}), i.e. OEC involves Mn{sub 4}(III{sub 2},IV{sub 4})-cluster and a S=0 state as the lowest energy electronic-spin state at S{sub 1}. The configuration of Mn oxidation numbers and the lowest energy spin state within the Mn{sub 4}-cluster depend on the protonation state of one oxo-anion bridging three Mn ions. When all water-ligands and oxo-bridges form H{sub 2}O and O{sup 2?}, respectively, the resulting OEC model involved Mn{sub 4}(III{sub 2},IV{sub 2})-cluster and one S=0 state as the lowest energy spin state. To rationalize the O{sup 2?}-bridge model at S{sub 1} state, a new H{sup +}-release scheme during the H{sub 2}O-splitting reaction is proposed.

Hatakeyama, Makoto; Ogata, Koji; Nakamura, Shinichiro [RIKEN Research Cluster for Innovation, Nakamura Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Uchida, Waka [Department of Biomolecular Engineering, Tokyo Institute of Technology, B-70, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

2013-12-10T23:59:59.000Z

356

BWR oxygen control demonstration program  

SciTech Connect (OSTI)

A number of cracks have occurred recently in certain BWR piping systems. The operating environment associated with oxidizing species such as oxygen and hydrogen peroxide is considered one of the factors in the mechanism of cracking. In April 1976, NWT Corporation was contracted to perform a BWR oxygen control demonstration program. Means for reducing reactor water oxygen and hydrogen peroxide concentrations during startup and shutdown transients were defined and demonstrated at Vermont Yankee and Browns Ferry Unit 3. Results of the demonstrations and an analytical review of impacts of major system variables on oxygen transients are discussed herein.

Pearl, W.L.; Kassen, W.R.; Sawochka, S.G.

1981-05-01T23:59:59.000Z

357

Oxygen to the core  

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

1-01 1-01 For immediate release: 01/10/2013 | NR-13-01-01 Oxygen to the core Anne M Stark, LLNL, (925) 422-9799, stark8@llnl.gov Printer-friendly An artist's conception of Earth's inner and outer core. LIVERMORE, Calif. -- An international collaboration including researchers from Lawrence Livermore National Laboratory has discovered that the Earth's core formed under more oxidizing conditions than previously proposed. Through a series of laser-heated diamond anvil cell experiments at high pressure (350,000 to 700,000 atmospheres of pressure) and temperatures (5,120 to 7,460 degrees Fahrenheit), the team demonstrated that the depletion of siderophile (also known as "iron loving") elements can be produced by core formation under more oxidizing conditions than earlier

358

Pool octanes via oxygenates  

SciTech Connect (OSTI)

Increasingly stringent antipollution regulations placed on automobile exhaust gases with consequent reduction or complete lead ban from motor gasoline result in octane shortage at many manufacturing sites. Attractive solutions to this problem, especially in conjunction with abundant methanol supplies, are the hydration and etherification of olefins contained in light product streams from cracking unit or produced by field gas dehydrogenation. A comparison is made between oxygenates octane-volume pool contributions and established refinery technologies. Process reviews for bulk manufacture of fuel-grade isopropanol (IPA), secondary butanol (SBA), tertiary butanol (TBA), methyl tertiary butyl ether (MTBE) and tertiary amyl methyl ether (TAME) are presented together with the characteristic investment and operating data. The implantation of these processes into a typical FCCU refinery complex with the resulting octane-pool improvement possibilities is descried.

Prezelj, M.

1987-09-01T23:59:59.000Z

359

Stable isotopes in late Pennsylvanian brachiopods: stratigraphic and paleoenvironmental implications  

E-Print Network [OSTI]

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...

Zhang, Chuanlun

2012-06-07T23:59:59.000Z

360

ISOTOPE FRACTIONATION Isotopes are atoms whose nuclei contain the same number of protons but a different number of neutrons. The  

E-Print Network [OSTI]

the most abundant isotope appears in the denominator: b R = b E / a E (stable boron isotopes = , [ ] [ ] [ ] [ ]OOCOOC2 OOCOOC2 O 16181616 16181818 CO 18 2 + + = . The isotopic composition, , of a sample, determined____________________________ ISOTOPE FRACTIONATION ____________________________ Isotopes are atoms

Zeebe, Richard E.

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Sulfur-isotope separation by distillation  

SciTech Connect (OSTI)

Sulfur-isotope separation by low-temperature distillation of hydrogen sulfide was studied in an 8-m, 25-mm diameter distillation column. Column temperature was controlled by a propane-propylene heat pipe. Column packing HETP was measured using nitric oxide in the column. The column was operated at pressures from 45 to 125 kPa. The relative volatility of S-32 vs. S-34 varied from 1.0008 to 1.0014.

Mills, T.R.

1982-01-01T23:59:59.000Z

362

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...

363

The High Flux Isotope Reactor at Oak Ridge National Laboratory  

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

The High Flux Isotope Reactor at ORNL The High Flux Isotope Reactor at ORNL Aerial of the High Flux Isotope Reactor Site The High Flux Isotope Reactor site is located on the south side of the ORNL campus and is about a three-minute drive from her sister neutron facility, the Spallation Neutron Source. Operating at 85 MW, HFIR is the highest flux reactor-based source of neutrons for research in the United States, and it provides one of the highest steady-state neutron fluxes of any research reactor in the world. The thermal and cold neutrons produced by HFIR are used to study physics, chemistry, materials science, engineering, and biology. The intense neutron flux, constant power density, and constant-length fuel cycles are used by more than 500 researchers each year for neutron scattering research into

364

Mantle Helium And Carbon Isotopes In Separation Creek Geothermal Springs,  

Open Energy Info (EERE)

Mantle Helium And Carbon Isotopes In Separation Creek Geothermal Springs, Mantle Helium And Carbon Isotopes In Separation Creek Geothermal Springs, Three Sisters Area, Central Oregon- Evidence For Renewed Volcanic Activity Or A Long Term Steady State System(Question) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Mantle Helium And Carbon Isotopes In Separation Creek Geothermal Springs, Three Sisters Area, Central Oregon- Evidence For Renewed Volcanic Activity Or A Long Term Steady State System(Question) Details Activities (1) Areas (1) Regions (0) Abstract: Here we present the helium and carbon isotope results from the initial study of a fluid chemistry-monitoring program started in the summer of 2001 near the South Sister volcano in central Oregon. The Separation Creek area which is several miles due west of the volcano is the locus of

365

MTBE, Oxygenates, and Motor Gasoline  

Gasoline and Diesel Fuel Update (EIA)

MTBE, Oxygenates, and MTBE, Oxygenates, and Motor Gasoline Contents * Introduction * Federal gasoline product quality regulations * What are oxygenates? * Who gets gasoline with oxygenates? * Which areas get MTBE? * How much has been invested in MTBE production capacity? * What does new Ethanol capacity cost? * What would an MTBE ban cost? * On-line information resources * Endnotes * Summary of revisions to this analysis Introduction The blending of methyl tertiary butyl ether (MTBE) into motor gasoline has increased dramatically since it was first produced 20 years ago. MTBE usage grew in the early 1980's in response to octane demand resulting initially from the phaseout of lead from gasoline and later from rising demand for premium gasoline. The oxygenated gasoline program stimulated an

366

Plants and Night Oxygen Production  

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

Plants and Night Oxygen Production Plants and Night Oxygen Production Name: Ashar Status: other Grade: other Location: Outside U.S. Country: India Date: Winter 2011-2012 Question: I would like to know if there are any plants which produces oxygen at night (without photosynthesis). I was told by a friend that Holy Basil (Ocimum tenuiflorum) produces oxygen even at night and I'm not convinced. I would like to get confirmation from experts. Replies: Some plants (particularly those of dry regions, e.g., deserts) only open their stomates at night to avoid drying out to intake CO2 (and output O2) (CAM photosynthesis) http://en.wikipedia.org/wiki/Crassulacean_acid_metabolism Sincerely, Anthony R. Brach, PhD Missouri Botanical Garden Bringing oxygen producing plants into your home is a way to mimic the healthy lifestyle factors of longevity in humans from the longest lived cultures.

367

Oxygen detection using evanescent fields  

DOE Patents [OSTI]

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.

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

2007-08-28T23:59:59.000Z

368

Apparatus and process for separating hydrogen isotopes  

DOE Patents [OSTI]

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.

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

2013-06-25T23:59:59.000Z

369

Stable Carbon Isotope Ratios of Phenolic Compounds in Secondary Particulate Organic Matter Formed by Photooxidation of Toluene  

E-Print Network [OSTI]

Compound-specific stable carbon isotope ratios for phenolic compounds in secondary particulate organic matter (POM) formed by photooxidation of toluene were studied. Secondary POM generated by photooxidation of toluene using a continuous-flow reactor and an 8 cubic meter indoor smog chamber was collected, and then extracted with acetonitrile. Eight phenolic compounds were identified in the extracts by a gas chromatograph coupled with a mass spectrometer, and their compound-specific stable carbon isotope ratios were determined by a gas chromatograph coupled with a combustion furnace followed by an isotope ratio mass spectrometer. The majority of the products, including methylnitrophenols and methylnitrocatechols, were isotopically depleted by 5 to 6 permil compared to the initial isotope ratio for toluene, whereas the isotope ratio for 4_nitrophenol remained the same as the initial isotope ratio for toluene. Based on the reaction mechanisms postulated in literature, stable carbon isotope ratios of these produc...

Irei, Satoshi; Huang, Lin; Auld, Janeen; Collin, Fabrice; Hastie, Donald

2014-01-01T23:59:59.000Z

370

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-01-01T23:59:59.000Z

371

Isotopic Analysis- Rock | Open Energy Information  

Open Energy Info (EERE)

Isotopic Analysis- Rock Isotopic Analysis- Rock Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Isotopic Analysis- Rock Details Activities (13) Areas (11) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Water rock interaction Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Isotopic Analysis- Rock: Isotopes are atoms of the same element that have different numbers of neutrons. An isotopic analysis looks at a particular isotopic element(s) in a given system, while the conditions which increase/decrease the number of neutrons are well understood and measurable.

372

Low Oxygen Environments in Chesapeake Bay  

E-Print Network [OSTI]

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

Boynton, Walter R.

373

Novel hybrid isotope separation scheme and apparatus  

DOE Patents [OSTI]

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.

Maya, J.

1991-06-18T23:59:59.000Z

374

Novel hybrid isotope separation scheme and apparatus  

DOE Patents [OSTI]

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.

Maya, Jakob (Brookline, MA)

1991-01-01T23:59:59.000Z

375

Frostbite Theater - Liquid Oxygen vs. Liquid Nitrogen - Liquid Oxygen and  

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

Cells vs. Liquid Nitrogen! Cells vs. Liquid Nitrogen! Previous Video (Cells vs. Liquid Nitrogen!) Frostbite Theater Main Index Next Video (Paramagnetism) Paramagnetism Liquid Oxygen and Fire! What happens when nitrogen and oxygen are exposed to fire? [ Show Transcript ] Announcer: Frostbite Theater presents... Cold Cuts! No baloney! Joanna and Steve: Just science! Joanna: Hi! I'm Joanna! Steve: And I'm Steve! Joanna: And this is a test tube of liquid nitrogen! Steve: And this is a test tube of liquid oxygen! Joanna: Let's see what happens when nitrogen and oxygen are exposed to fire. Steve: Fire?! Joanna: Yeah! Steve: Really?! Joanna: Why not! Steve: Okay! Joanna: As nitrogen boils, it changes into nitrogen gas. Because it's so cold, it's denser than the air in the room. The test tube fills up with

376

Raman spectroscopic and mass spectrometric investigations of the hydrogen isotopes and isotopically labelled methane  

SciTech Connect (OSTI)

Suitable analytical methods must be tested and developed for monitoring the individual process steps within the fuel cycle of a fusion reactor and for tritium accountability. The utility of laser-Raman spectroscopy accompanied by mass spectrometry with an Omegatron was investigated using the analysis of all hydrogen isotopes and isotopically labeled methanes as an example. The Omegatron is useful for analyzing all hydrogen isotopes mixed with the stable helium isotopes. The application of this mass spectrometer were demonstrated by analyzing mixtures of deuterated methanes. In addition, it was employed to study the radiochemical Witzbach exchange reaction between tritium and methanes. A laser-Raman spectrometer was designed for analysis of tritium-containing gases and was built from individual components. A tritium-compatible, metal-sealed Raman cuvette having windows with good optical properties and additional means for measuring the stray light was first used successfully in this work. The Raman spectra of the hydrogen isotopes were acquired in the pure rotation mode and in the rotation-vibration mode and were used for on. The deuterated methanes were measured by Raman spectroscopy, the wavenumbers determined were assigned to the corresponding vibrations, and the wavenumbers for the rotational fine-structure were summarized in tables. The fundamental Vibrations of the deuterated methanes produced Witzbach reactions were detected and assigned. The fundamental vibrations of the molecules were obtained with Raman spectroscopy for the first time in this work. The @-Raman spectrometer assembled is well suited for the analysis of tritium- containing gases and is practical in combination with mass spectrometry using an Omegatron, for studying gases used in fusion.

Jewett, J.R., Fluor Daniel Hanford

1997-02-24T23:59:59.000Z

377

Oxygen transfer in the implant environment  

E-Print Network [OSTI]

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

Goor, Jared Braden

2007-01-01T23:59:59.000Z

378

OXYGEN DIFFUSION IN UO2-x  

E-Print Network [OSTI]

~ 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.

Kim, K.C.

2013-01-01T23:59:59.000Z

379

PRIMARY RESEARCH PAPER Water column oxygen demand and sediment oxygen flux  

E-Print Network [OSTI]

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

Mallin, Michael

380

Synthesis, Characterization, and Oxygenation Studies of Carboxylate-Bridged Diiron(II) Complexes with Aromatic Substrates Tethered to Pyridine Ligands and the Formation of a Unique Trinuclear Complex  

E-Print Network [OSTI]

In this study, diiron(II) complexes were synthesized as small molecule mimics of the reduced active sites in the hydroxylase components of bacterial multicomponent monooxygenases (BMMs). Tethered aromatic substrates were ...

Friedle, Simone

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Copper isotope fractionation in acid mine drainage. | EMSL  

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

Copper isotope fractionation in acid mine drainage. Copper isotope fractionation in acid mine drainage. Abstract: We surveyed the Cu isotopic composition of primary minerals and...

382

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...

383

Polycyclic Aromatic Triptycenes: Oxygen Substitution Cyclization Strategies  

E-Print Network [OSTI]

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 ...

VanVeller, Brett

384

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...

385

Angling chromium to let oxygen through | EMSL  

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

which enable facile oxygen anion diffusion at low temperature. Brighter spheres are strontium ions; less-bright spheres are chromium ions. Oxygen anions are barely visible, and...

386

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...

387

OXYGEN DIFFUSION IN HYPOSTOICHIOMETRIC URANIUM DIOXIDE  

E-Print Network [OSTI]

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

Kim, Kee Chul

2010-01-01T23:59:59.000Z

388

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...

389

Platinum Monolayer Electrocatalysts for Oxygen Reduction Reaction...  

Broader source: Energy.gov (indexed) [DOE]

Platinum Monolayer Electrocatalysts for Oxygen Reduction Reaction Platinum Monolayer Electrocatalysts for Oxygen Reduction Reaction Presentation slides from the June 19, 2012, Fuel...

390

Oxygenate Supply/Demand Balances  

Gasoline and Diesel Fuel Update (EIA)

Oxygenate Supply/Demand Oxygenate Supply/Demand Balances in the Short-Term Integrated Forecasting Model By Tancred C.M. Lidderdale This article first appeared in the Short-Term Energy Outlook Annual Supplement 1995, Energy Information Administration, DOE/EIA-0202(95) (Washington, DC, July 1995), pp. 33-42, 83-85. The regression results and historical data for production, inventories, and imports have been updated in this presentation. Contents * Introduction o Table 1. Oxygenate production capacity and demand * Oxygenate demand o Table 2. Estimated RFG demand share - mandated RFG areas, January 1998 * Fuel ethanol supply and demand balance o Table 3. Fuel ethanol annual statistics * MTBE supply and demand balance o Table 4. EIA MTBE annual statistics * Refinery balances

391

The System BoronOxygen  

Science Journals Connector (OSTI)

This presentation covers the years 1985 to 1988 and, in part, to 1992. It continues the previous discussion of the system boronoxygen in Boron Compounds 3rd Suppl. Vol. 2, 1987, pp. 1/184, and earlier liter...

Gert Heller

1993-01-01T23:59:59.000Z

392

Studies on the Surface Oxygen Species and the Catalytic Activity for CO Oxidation of La1-xSrxCo1-xMnxO3, a Perovskite-Type Oxides Catalyst  

Science Journals Connector (OSTI)

The surface oxygen distribution the active oxygen species for CO on the perovskite-type catalyst La1-xSrxCo1-xMnxO3...and its catalytic oxidation activity with CO as probe were investigated by means of XRD, TPD a...

Rong Li; Jiantai Ma; Jingli Xu; Xia Zhou

2000-07-01T23:59:59.000Z

393

PLANETARY-SCALE STRONTIUM ISOTOPIC HETEROGENEITY AND THE AGE OF VOLATILE DEPLETION OF EARLY SOLAR SYSTEM MATERIALS  

SciTech Connect (OSTI)

Isotopic anomalies in planetary materials reflect both early solar nebular heterogeneity inherited from presolar stellar sources and processes that generated non-mass-dependent isotopic fractionations. The characterization of isotopic variations in heavy elements among early solar system materials yields important insight into the stellar environment and formation of the solar system, and about initial isotopic ratios relevant to long-term chronological applications. One such heavy element, strontium, is a central element in the geosciences due to wide application of the long-lived {sup 87}Rb-{sup 87}Sr radioactive as a chronometer. We show that the stable isotopes of Sr were heterogeneously distributed at both the mineral scale and the planetary scale in the early solar system, and also that the Sr isotopic heterogeneities correlate with mass-independent oxygen isotope variations, with only CI chondrites plotting outside of this correlation. The correlation implies that most solar system material formed by mixing of at least two isotopically distinct components: a CV-chondrite-like component and an O-chondrite-like component, and possibly a distinct CI-chondrite-like component. The heterogeneous distribution of Sr isotopes may indicate that variations in initial {sup 87}Sr/{sup 86}Sr of early solar system materials reflect isotopic heterogeneity instead of having chronological significance, as interpreted previously. For example, given the differences in {sup 84}Sr/{sup 86}Sr between calcium aluminum inclusions and eucrites ({epsilon}{sup 84}Sr > 2), the difference in age between these materials would be {approx}6 Ma shorter than previously interpreted, placing the Sr chronology in agreement with other long- and short-lived isotope systems, such as U-Pb and Mn-Cr.

Moynier, Frederic; Podosek, Frank A. [Department of Earth and Planetary Science and McDonnell Center for Space Sciences, Washington University, St. Louis, MO 63130 (United States); Day, James M. D. [Geosciences Research Division, Scripps Institution of Oceanography, La Jolla, CA 92093-0244 (United States); Okui, Wataru; Yokoyama, Tetsuya [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Bouvier, Audrey [Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455-0231 (United States); Walker, Richard J., E-mail: moynier@levee.wustl.edu, E-mail: fap@levee.wustl.edu, E-mail: jmdday@ucsd.edu, E-mail: rjwalker@umd.edu, E-mail: okui.w.aa@m.titech.ac.jp, E-mail: tetsuya.yoko@geo.titech.ac.jp, E-mail: abouvier@umn.edu [Department of Geology, University of Maryland, College Park, MD 20742 (United States)

2012-10-10T23:59:59.000Z

394

Definition: Isotopic Analysis | Open Energy Information  

Open Energy Info (EERE)

Analysis Analysis Jump to: navigation, search Dictionary.png Isotopic Analysis Isotopes are atoms of the same element that have different numbers of neutrons. An isotopic analysis looks at a particular isotopic element(s) in a given system, while the conditions which increase/decrease the number of neutrons are well understood and measurable.[1] View on Wikipedia Wikipedia Definition Isotope analysis is the identification of isotopic signature, the distribution of certain stable isotopes and chemical elements within chemical compounds. This can be applied to a food web to make it possible to draw direct inferences regarding diet, trophic level, and subsistence. Isotope ratios are measured using mass spectrometry, which separates the different isotopes of an element on the basis of their mass-to-charge

395

Novel Membranes and Processes for Oxygen Enrichment  

SciTech Connect (OSTI)

The overall goal of this project is to develop a membrane process that produces air containing 25-35% oxygen, at a cost of $25-40/ton of equivalent pure oxygen (EPO2). Oxygen-enriched air at such a low cost will allow existing air-fueled furnaces to be converted economically to oxygen-enriched furnaces, which in turn will improve the economic and energy efficiency of combustion processes significantly, and reduce the cost of CO{sub 2} capture and sequestration from flue gases throughout the U.S. manufacturing industries. During the 12-month Concept Definition project: We identified a series of perfluoropolymers (PFPs) with promising oxygen/nitrogen separation properties, which were successfully made into thin film composite membranes. The membranes showed oxygen permeance as high as 1,200 gpu and oxygen/nitrogen selectivity of 3.0, and the permeance and selectivity were stable over the time period tested (60 days). We successfully scaled up the production of high-flux PFP-based membranes, using MTR's commercial coaters. Two bench-scale spiral-wound modules with countercurrent designs were made and parametric tests were performed to understand the effect of feed flow rate and pressure, permeate pressure and sweep flow rate on the membrane module separation properties. At various operating conditions that modeled potential industrial operating conditions, the module separation properties were similar to the pure-gas separation properties in the membrane stamps. We also identified and synthesized new polymers [including polymers of intrinsic microporosity (PIMs) and polyimides] with higher oxygen/nitrogen selectivity (3.5-5.0) than the PFPs, and made these polymers into thin film composite membranes. However, these membranes were susceptible to severe aging; pure-gas permeance decreased nearly six-fold within two weeks, making them impractical for industrial applications of oxygen enrichment. We tested the effect of oxygen-enriched air on NO{sub x} emissions using a Bloom baffle burner at GTI. The results are positive and confirm that oxygen-enriched combustion can be carried out without producing higher levels of NOx than normal air firing, if lancing of combustion air is used and the excess air levels are controlled. A simple economic study shows that the membrane processes can produce O{sub 2} at less than $40/ton EPO{sub 2} and an energy cost of 1.1-1.5 MMBtu/ton EPO{sub 2}, which are very favorable compared with conventional technologies such as cryogenics and vacuum pressure swing adsorption processes. The benefits of integrated membrane processes/combustion process trains have been evaluated, and show good savings in process costs and energy consumption, as well as reduced CO{sub 2} emissions. For example, if air containing 30% oxygen is used in natural gas furnaces, the net natural gas savings are an estimated 18% at a burner temperature of 2,500 F, and 32% at a burner temperature of 3,000 F. With a 20% market penetration of membrane-based oxygen-enriched combustion in all combustion processes by 2020, the energy savings would be 414-736 TBtu/y in the U.S. The comparable net cost savings are estimated at $1.2-2.1 billion per year by 2020, calculated as the value of fuel savings subtracted from the cost of oxygen production. The fuel savings of 18%-32% by the membrane/oxygen-enriched combustion corresponds to an 18%-32% reduction in CO{sub 2} emissions, or 23-40 MM ton/y less CO{sub 2} from natural gas-fired furnaces by 2020. In summary, results from this project (Concept Definition phase) are highly promising and clearly demonstrate that membrane processes can produce oxygen-enriched air in a low cost manner that will lower operating costs and energy consumption in industrial combustion processes. Future work will focus on proof-of-concept bench-scale demonstration in the laboratory.

Lin, Haiqing

2011-11-15T23:59:59.000Z

396

Yucca Mountain Area Saturated Zone Dissolved Organic Carbon Isotopic Data  

SciTech Connect (OSTI)

Groundwater samples in the Yucca Mountain area were collected for chemical and isotopic analyses and measurements of water temperature, pH, specific conductivity, and alkalinity were obtained at the well or spring at the time of sampling. For this project, groundwater samples were analyzed for major-ion chemistry, deuterium, oxygen-18, and carbon isotopes of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). The U.S. Geological Survey (USGS) performed all the fieldwork on this project including measurement of water chemistry field parameters and sample collection. The major ions dissolved in the groundwater, deuterium, oxygen-18, and carbon isotopes of dissolved inorganic carbon (DIC) were analyzed by the USGS. All preparation and processing of samples for DOC carbon isotopic analyses and geochemical modeling were performed by the Desert Research Institute (DRI). Analysis of the DOC carbon dioxide gas produced at DRI to obtain carbon-13 and carbon-14 values was conducted at the University of Arizona Accelerator Facility (a NSHE Yucca Mountain project QA qualified contract facility). The major-ion chemistry, deuterium, oxygen-18, and carbon isotopes of DIC were used in geochemical modeling (NETPATH) to determine groundwater sources, flow paths, mixing, and ages. The carbon isotopes of DOC were used to calculate groundwater ages that are independent of DIC model corrected carbon-14 ages. The DIC model corrected carbon-14 calculated ages were used to evaluate groundwater travel times for mixtures of water including water beneath Yucca Mountain. When possible, groundwater travel times were calculated for groundwater flow from beneath Yucca Mountain to down gradient sample sites. DOC carbon-14 groundwater ages were also calculated for groundwaters in the Yucca Mountain area. When possible, groundwater travel times were estimated for groundwater flow from beneath Yucca Mountain to down gradient groundwater sample sites using the DOC calculated groundwater ages. The DIC calculated groundwater ages were compared with DOC calculated groundwater ages and both of these ages were compared to travel times developed in ground-water flow and transport models. If nuclear waste is stored in Yucca Mountain, the saturated zone is the final barrier against the release of radionuclides to the environment. The most recent rendition of the TSPA takes little credit for the presence of the saturated zone and is a testament to the inadequate understanding of this important barrier. If radionuclides reach the saturated zone beneath Yucca Mountain, then there is a travel time before they would leave the Yucca Mountain area and flow down gradient to the Amargosa Valley area. Knowing how long it takes groundwater in the saturated zone to flow from beneath Yucca Mountain to down gradient areas is critical information for potential radionuclide transport. Radionuclide transport in groundwater may be the quickest pathway for radionuclides in the proposed Yucca Mountain repository to reach land surface by way of groundwater pumped in Amargosa Valley. An alternative approach to ground-water flow and transport models to determine the travel time of radionuclides from beneath Yucca Mountain to down gradient areas in the saturated zone is by carbon-14 dating of both inorganic and organic carbon dissolved in the groundwater. A standard method of determining ground-water ages is to measure the carbon-13 and carbon-14 of DIC in the groundwater and then correct the measured carbon-14 along a flow path for geochemical reactions that involve carbon containing phases. These geochemical reactions are constrained by carbon-13 and isotopic fractionations. Without correcting for geochemical reactions, the ground-water ages calculated from only the differences in carbon-14 measured along a flow path (assuming the decrease in carbon-14 is due strictly to radioactive decay) could be tens of thousands of years too old. The computer program NETPATH, developed by the USGS, is the best geochemical program for correcting carbon-14 activities for geochemical r

Thomas, James; Decker, David; Patterson, Gary; Peterman, Zell; Mihevc, Todd; Larsen, Jessica; Hershey, Ronald

2007-06-25T23:59:59.000Z

397

Increased intrapulmonary retention of radiolabeled neutrophils in early oxygen toxicity  

SciTech Connect (OSTI)

Sequential lung injuries, such as oxygen toxicity followed by septicemia, are common during the adult respiratory distress syndrome (ARDS). As these forms of vascular injury may be mediated in part by polymorphonuclear leukocytes (PMN), aberrant interactions between PMN and previously injured pulmonary endothelium are of both theoretical interest and clinical importance. The present study was undertaken to test the hypothesis that early oxygen toxicity at a dose that injuries pulmonary endothelium relatively selectively alters intrapulmonary neutrophil kinetics. Unanesthetized rats breathing 1.0 atmospheres oxygen for 36 h showed ultrastructural endothelial damage but no edema, injury, or neutrophilic inflammation by histologic criteria. However, in these oxygen-toxic animals, whereas initial accumulation of radiolabeled PMN in lungs was normal, washout of PMN was abnormal at 120 min after infusion, at which point the pulmonary retention of radiolabeled PMN in the lungs of oxygen-treated animals was significantly higher than in control animals (139% of control, p less than 0.0096). Features of our methodology, including avoidance of osmotic stress and use of paired control animals, appear to have greatly enhanced the sensitivity of radiolabeled neutrophils for detecting a subtle abnormality of neutrophil-endothelial interactions. Our studies in the oxygen toxicity model provide the first demonstration in vivo of abnormal intrapulmonary neutrophil kinetics in early oxygen toxicity prior to the onset of histologic evidence of lung injury or inflammation.

Rinaldo, J.E.; English, D.; Levine, J.; Stiller, R.; Henson, J.

1988-02-01T23:59:59.000Z

398

Researchers Directly Observe Oxygen Signature in the Oxygen-evolving  

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

Researchers Directly Observe Oxygen Signature in the Researchers Directly Observe Oxygen Signature in the Oxygen-evolving Complex of Photosynthesis Arguably the most important chemical reaction on earth is the photosynthetic splitting of water to molecular oxygen by the Mn-containing oxygen-evolving complex (Mn-OEC) in the protein known as photosystem II (PSII). It is this reaction which has, over the course of some 3.8 billion years, gradually filled our atmosphere with O2 and consequently enabled and sustained the evolution of complex aerobic life. Coupled to the reduction of carbon dioxide, biological photosynthesis contributes foodstuffs for nutrition while recycling CO2 from the atmosphere and replacing it with O2. By utilizing sunlight to power these energy-requiring reactions, photosynthesis also serves as a model for addressing societal energy needs as we enter an era of diminishing fossil fuel resources and climate change. Understanding, at the molecular level, the dynamics and mechanisms behind photosynthesis is of fundamental importance and will prove critical to the future design of devices aimed at converting sunlight into electrochemical energy and transportable fuel.

399

Isotopic Analysis At Geysers Area (Lambert & Epstein, 1992) | Open Energy  

Open Energy Info (EERE)

Isotopic Analysis- Rock At Geysers Area (Lambert & Isotopic Analysis- Rock At Geysers Area (Lambert & Epstein, 1992) Exploration Activity Details Location Geysers Area Exploration Technique Isotopic Analysis- Rock Activity Date Usefulness useful DOE-funding Unknown Notes Measurements of 180/160, 13C/12C and D/H ratio variations were made by the usual methods (McCrea, 1950; Taylor and Epstein, 1962; Epstein and Taylor, 1970) using mass spectrometers of the type described by Nier (1947) with modifications by McKinney et al. (1950). Results are reported in 8-notation with respect to the SMOW (Craig, 1961 ) and PDB (Urey et al., 1951 ) standards. Analytical precisions for multiple analyses of any single sample were _+ 0.2%0 for oxygen and carbon and _ 1%o for hydrogen. Inhomogeneities of cuttings fractions gave rise to variations within single cuttings

400

Isotopic Analysis-Fluid At Long Valley Caldera Geothermal Area (1977) |  

Open Energy Info (EERE)

Fluid At Long Valley Caldera Geothermal Area (1977) Fluid At Long Valley Caldera Geothermal Area (1977) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis-Fluid At Long Valley Caldera Geothermal Area (1977) Exploration Activity Details Location Long Valley Caldera Geothermal Area Exploration Technique Isotopic Analysis-Fluid Activity Date 1977 Usefulness not indicated DOE-funding Unknown Exploration Basis Estimate deep reservoir temperature Notes The oxygen isotope compositions of dissolved sulfate and water from hot springs and shallow drillholes have been tested. Methods are described to calculate the effects of boiling and dilution. The geothermometer, is applied to thermal systems of Yellowstone Park, Wyoming, Long Valley, California, and Raft River, Idaho to estimate deep reservoir temperatures

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

OXYGEN ADSORPTION ON NITROGEN CONTAINING CARBON SURFACES  

E-Print Network [OSTI]

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

Truong, Thanh N.

402

In Situ Studies of the Active Sites for the Water Gas Shift Reaction over Cu-CeO2 Catalysts: Complex Interaction Between Metallic Copper and Oxygen Vacancies of Ceria  

SciTech Connect (OSTI)

New information about the active sites for the water gas shift (WGS) reaction over Cu-CeO{sub 2} systems was obtained using in-situ, time-resolved X-ray diffraction (TR-XRD), X-ray absorption spectroscopy (TR-XAS, Cu K and Ce L3 edges), and infrared spectroscopy (DRIFTS). Cu-CeO{sub 2} nanoparticles prepared by a novel reversed microemulsion method (doped Ce1-xCuxO2 sample) and an impregnation method (impregnated CuO{sub x}/CeO{sub 2} sample) were studied. The results from all of the samples indicate that both metallic copper and oxygen vacancies in ceria were involved in the generation of active sites for the WGS reaction. Evidence was found for a synergistic Cu-O vacancy interaction. This interaction enhances the chemical activity of Cu, and the presence of Cu facilitates the formation of O vacancies in ceria under reaction conditions. Water dissociation occurred on the O vacancy sites or the Cu-O vacancy interface. No significant amounts of formate were formed on the catalysts during the WGS reaction. The presence of strongly bound carbonates is an important factor for the deactivation of the catalysts at high temperatures. This work identifies for the first time the active sites for the WGS reaction on Cu-CeO{sub 2} catalysts and illustrates the importance of in situ structural studies for heterogeneous catalytic reactions.

Wang,X.; Rodriguez, J.; Hanson, J.; Gamarra, D.; Martinez-Arias, A.; Fernandez-Garcia, M.

2006-01-01T23:59:59.000Z

403

Flammability of selected heat resistant alloys in oxygen gas mixtures  

SciTech Connect (OSTI)

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.

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

1995-12-31T23:59:59.000Z

404

Measuring oxygen reduction/evolution reactions on the nanoscale  

SciTech Connect (OSTI)

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.

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

405

Boron isotope geochemistry during diagenesis. Part I. Experimental determination of fractionation during illitization of smectite  

Science Journals Connector (OSTI)

Experiments were performed to measure the isotopic fractionation of boron between illite/smectite (I/S) clay minerals and water as a function of temperature (300 and 350C) and degree of illitization. Corresponding changes in the oxygen isotopes were monitored as an indication of the approach to equilibrium. The kinetics of the B-isotope exchange follows the mineralogical restructuring of smectite as it recrystallizes to illite. An initial decline in ?11BI/S occurs when the I/S is randomly ordered (RO). The ?11BI/S values reach a plateau during R1 ordering of the I/S, representing a metastable condition. The greatest change in ?11BI/S is observed during long-range (R3) ordering of the I/S when neoformation occurs. Values of ?11BI/S measured on the equilibrium reaction products were used to construct a B-isotope fractionation curve. There is a linear correlation among data from these experiments and 1100C basaltic melt-fluid fractionation experiments (Hervig and Moore, 2000) that can be extrapolated to include adsorption experiments at 25C (Palmer et al., 1987). Unlike other stable isotopic systems (e.g., oxygen) there is no mineral-specific fractionation of B-isotopes, but rather a coordination dependence of the fractionation. Under diagenetic conditions B is predominantly in trigonal coordination in fluids but substitutes in tetrahedral sites of silicates. The preference of 10B for tetrahedral bonds is the major fractionating factor of B in silicates.

Lynda B Williams; Richard L Hervig; John R Holloway; Ian Hutcheon

2001-01-01T23:59:59.000Z

406

Vibrational Dynamics of Isotopically Dilute Nitrogen to 104 GPa  

Science Journals Connector (OSTI)

Raman studies to 104 GPa of a 14N2 host with dilute 15N2 and 14N15N isotopic species indicate an increase in vibrational coupling with pressure. The lowest frequency branch of the isotopic species 15N2 reaches a plateau around 100 GPa suggesting the onset of bond weakening for molecules located on particular sites. An unusual intensity increase is observed for the isotopic ?1 guest modes. The phase transitions above 20 GPa appear to involve an increase in the number of inequivalent sites, with possibly subtle changes in the orientational behavior of particular molecules in the pressure range 25 to 50 GPa not readily revealed in recent x-ray diffraction studies.

H. Olijnyk and A. P. Jephcoat

1999-07-12T23:59:59.000Z

407

AVLIS enrichment of medical isotopes  

SciTech Connect (OSTI)

Under the Sponsorship of the United states Enrichment Corporation (USEC), we are currently investigating the large scale separation of several isotopes of medical interest using atomic vapor isotope separation (AVLIS). This work includes analysis and experiments in the enrichment of thallium 203 as a precursor to the production of thallium 201 used in cardiac imaging following heart attacks, on the stripping of strontium 84 from natural strontium as precursor to the production of strontium 89, and on the stripping of lead 210 from lead used in integrated circuits to reduce the number of alpha particle induced logic errors.

Haynam, C.A.; Scheibner, K.F.; Stern, R.C.; Worden, E.F. [Lawrence Livermore National Laboratory, CA (United States)

1996-12-31T23:59:59.000Z

408

Spinelolivine magnesium isotope thermometry in the mantle and implications for the Mg isotopic composition of Earth  

E-Print Network [OSTI]

Spinel­olivine magnesium isotope thermometry in the mantle and implications for the Mg isotopic: magnesium isotopes mantle geochemistry meteorites MC-ICPMS The magnesium isotopic composition of Earth., 2004; Poitrasson et al., 2005; Georg et al., 2007; Poitrasson, 2007; Weyer et al., 2007). Magnesium

Manning, Craig

409

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.

410

Magnesium Isotope Effects in Enzymatic Phosphorylation  

Science Journals Connector (OSTI)

So far as magnesium isotope effect in phosphorylation is an unexpected and unusual phenomenon, it is worthy to shortly describe materials and technologies used in isotopic biochemical experiments. ... Isotope-containing MgCl2 samples were obtained using treatment of magnesium oxides 24MgO, 25MgO, 26MgO, and *MgO with analytically pure HCl (*Mg means magnesium with natural abundance of the three isotopes; see Table 1). ...

Anatoly L. Buchachenko; Dmitry A. Kouznetsov; Natalia N. Breslavskaya; Marina A. Orlova

2008-02-05T23:59:59.000Z

411

Magnetic Isotope Effect in the Photolysis of Organotin Compounds  

Science Journals Connector (OSTI)

Fractionation of isotopes in chemical and biochemical reactions is induced by two isotope effects; their origin and physical nature are shown in Figure 1. ... The classical isotope effect (CIE) sorts isotopic nuclei on their masses; the magnetic isotope effect (MIE) demonstrates nuclear spin selectivity of reactions and separates isotopic nuclei according to their magnetic moments.1 ...

Anatoly L. Buchachenko; Vladimir L. Ivanov; Vitaly A. Roznyatovsky; Yuri A. Ustynyuk

2006-03-02T23:59:59.000Z

412

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the fifth quarterly report on a new study to develop a ceramic membrane/metal joint. Results of wetting experiments on commercially available Nickel based brazing alloys on perovskite surfaces are described. Additionally, experimental and numerical investigations on the strength of concentric ceramic/metal joints are presented.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2001-02-01T23:59:59.000Z

413

On The Importance of Organic Oxygen for Understanding Organic Aerosol  

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

On The Importance of Organic Oxygen for Understanding Organic Aerosol On The Importance of Organic Oxygen for Understanding Organic Aerosol Particles Title On The Importance of Organic Oxygen for Understanding Organic Aerosol Particles Publication Type Journal Article Year of Publication 2006 Authors Pang, Yanbo, B. J. Turpin, and Lara A. Gundel Journal Journal of Aerosol Science and Technology Volume 40 Start Page Chapter Pagination 128-133 Abstract This study shows how aerosol organic oxygen data could provide new and independent information about organic aerosol mass, aqueous solubility of organic aerosols, formation of secondary organic aerosol (SOA) and the relative contributions of anthropogenic and biogenic sources. For more than two decades atmospheric aerosol organic mass concentration has usually been estimated by multiplying the measured carbon content by an assumed organic mass (OM)-to-organic carbon (OC ) factor of 1.4. However, this factor can vary from 1.0 to 2.5 depending on location. This great uncertainty about aerosol organic mass limits our understanding of the influence of organic aerosol on climate, visibility and health.New examination of organic aerosol speciation data shows that the oxygen content is the key factor responsible for the observed range in the OM-to-OC factor. When organic oxygen content is excluded, the ratio of non-oxygen organic mass to carbon mass varies very little across different environments (1.12 to 1.14). The non-oxygen-OM-to-non-oxygen OC factor for all studied sites (urban and non-urban) is 1.13± 0.02. The uncertainty becomes an order of magnitude smaller than the uncertainty in the best current estimates of organic mass to organic carbon ratios (1.6± 0.2 for urban and 2.1± 0.2 for non-urban areas). When aerosol organic oxygen data become available, organic aerosol mass can be quite accurately estimated using just OC and organic oxygen (OO) without the need to know whether the aerosol is fresh or aged. In addition, aerosol organic oxygen data will aid prediction of water solubility since compounds with OO-to-OC higher than 0.4 have water solubilities higher than 1g per 100 g water

414

doi:10.1016/S0016-7037(02)01176-6 Experimental study of evaporation and isotopic mass fractionation of potassium in silicate  

E-Print Network [OSTI]

chondrule composition melts was studied using a vacuum furnace. Though Na is the less volatile of the two. With long heating duration, the release of light K condensed within the furnace leads to interaction and evolution of the solar system depends greatly on how well we understand the solar nebular environment

415

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the fourth quarterly report on a new study to develop a ceramic membrane/metal joint. The first experiments using the La-Sr-Fe-O ceramic are reported. Some of the analysis performed on the samples obtained are commented upon. A set of experiments to characterize the mechanical strength and thermal fatigue properties of the joints has been designed and begun. Finite element models of joints used to model residual stresses are described.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2000-07-01T23:59:59.000Z

416

Strontium isotope geochemistry of alluvial groundwater: a tracer for groundwater resources characterisation Hydrology and Earth System Sciences, 8(5), 959972 (2004) EGU  

E-Print Network [OSTI]

Strontium isotope geochemistry of alluvial groundwater: a tracer for groundwater resources characterisation 959 Hydrology and Earth System Sciences, 8(5), 959972 (2004) © EGU Strontium isotope geochemistry for corresponding author : p.negrel@brgm.fr Abstract This study presents strontium isotope and major ion data

Paris-Sud XI, Université de

417

Oxygenated fuels for clean heavy-duty diesel engines  

Science Journals Connector (OSTI)

For diesel engines, changing the fuel composition is an alternative route towards achieving lower emission levels. The potential of oxygenated fuels to significantly reduce particulate matter emissions has already been demonstrated earlier. In this study, this research has been extrapolated towards lower emission levels. Exhaust gas recirculation (EGR) was applied to a modern EURO-3-type HD diesel engine. Tests were done at different engine working points, with EGR-levels and start of fuel delivery timings set to give NOx emissions between 3.5 and 2.0 g/kWh with regular diesel fuel. Fourteen blends of a low-sulphur diesel fuel respectively of a gas-to-liquid synthetic diesel fuel with different oxygenates were tested. The corresponding fuel matrix covers a range of fuel oxygen mass fractions up to 15%. Results are presented and the impact of fuel oxygen mass fraction and Cetane Number are analysed and compared with results from previous research.

P.J.M. Frijters; R.S.G. Baert

2006-01-01T23:59:59.000Z

418

E-Print Network 3.0 - accumulate reactive oxygen Sample Search...  

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

Sciences, University of Manitoba Collection: Geosciences 90 Transient Studies of Oxygen Removal Pathways and Catalytic Redox Cycles during NO Decomposition on Cu-ZSM5 Summary: ....

419

Effect of metal oxide and oxygen on the growth of single-walled carbon nanotubes by electric arc discharge  

Science Journals Connector (OSTI)

The effect of oxygen on the growth of single-walled carbon nanotubes was studied with NiCo alloy powder as catalyst under helium atmosphere of 500Torr by electric arc discharge. The oxygen included in nickel or...

Delong He; Yongning Liu; Tingkai Zhao; Jiewu Zhu

2008-03-01T23:59:59.000Z

420

Oxygen sorption and thermal regeneration of sorption centers on catalysts of ammonia synthesis in helium and hydrogen flow  

Science Journals Connector (OSTI)

The interaction of oxygen with catalysts for ammonia synthesis in helium and hydrogen flow has been studied. Various catalysts sorb from 7 to 12 oxygen layers. 2 to 4 layers can be removed by thermal activatio...

A. V. Krylova; V. V. Morozov; S. S. Lachinov

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

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.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2003-01-01T23:59:59.000Z

422

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

In this quarter a systematic analysis on the decomposition behavior of the OTM membranes at air and nitrogen were initiated to understand the structural and stoichiometric changes associated with elevated temperatures. Evaluation of the flexural strengths using 4-point bend test was also started for the dual phase membranes. Initial results on the synthesis of dual phase composite materials have been obtained. The measurements have focused on the compatibility of mixed conductors with the pure ionic conductors yttria stabilized zirconia (YSZ) and gadolinium doped ceria (GDC). The initial results obtained for three different mixed conductors suggest that (GDC) is the better choice. A new membrane permeation system has been designed and tested and sintering studies of biphasic systems are in progress.

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

2006-05-01T23:59:59.000Z

423

Magnesium-Isotope Fractionation During Plant Growth  

Science Journals Connector (OSTI)

With three stable isotopes naturally abundant (24Mg, 78.992%; 25Mg, 10.003%; 26Mg, 11.005%), magnesium stable isotope fractionation may provide insights into these cycles. ... Measurements of the magnesium isotopic composition of chlorophylls, seeds, shoots, roots, leaves, exudates, and the limiting nutrient solution over time show that the plant appears to establish an isotopic equilibrium with the nutrient available to it and that the plant (in particular, the seeds and exudates) becomes enriched in the heavy isotopes of magnesium in a mass-dependent relationship as the plant reaches maturity. ...

Jay R. Black; Emanuel Epstein; William D. Rains; Qing-zhu Yin; William H. Casey

2008-10-01T23:59:59.000Z

424

Rare Isotopes in Cosmic Explosions and Accelerators on Earth  

ScienceCinema (OSTI)

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.

Hendrik Schatz

2010-01-08T23:59:59.000Z

425

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

A non-agglomerated and nanocrystalline-sized powder was successfully produced using ethylene glycol nitrate methods. The LSFT powder prepared using this method exhibits well dispersed and nano-sized particles about 100-200 nm. The density of LSFT sintered at 1300 C was about 90% of the theoretical density at which is 100 C less than that of the previous LSFT which was sintered at 1400 C. The sample sintered at 1400 C exhibited the evidence of a liquid phase at the grain boundaries and 2nd phase formation which probably caused low mechanical stability. The electrical conductivity and Seebeck coefficient were measured as a function of temperature. The LSFT-CGO specimens were cut from the as sintered bars and used for the evaluation of Mechanical Properties after polishing. The effect of strain rate on the flexural strength of the LSFT-CGO test specimens was studied. Three strain rates 6, 60 and 600 {micro}m/ min were chosen for this study. It is observed from the results that with increasing cross head speed the membrane takes higher loads to fail. A reduction in the strength of the membrane was observed at 1000 C in N{sub 2}. Two different routes were investigated to synthesis GDC using either formate or carbonate precursors. The precursor and CGO particle morphologies were examined by scanning electron microscopy. The thermal decomposition behaviors of Ce(Gd)(HCOO){sub 3} and Ce(Gd)(CO{sub 3})(OH) were determined by thermogravimetric analysis (TGA) at a rate of 3 C/min in air. The X-ray powder diffraction patterns of the precursor and CGO were collected and nitrogen adsorption isotherms were measured. Conductivity measurements were made by AC impedance spectroscopy on sintered disks in air using platinum electrodes.

S. Bandopadhyay; T. Nithyanantham

2006-06-30T23:59:59.000Z

426

Isotope Effects in Isotope-Exchange Reactions:? Evidence for a Large 12C/13C Kinetic Isotope Effect in the Gas Phase  

Science Journals Connector (OSTI)

Isotope effects are key to understanding reaction mechanisms because isotopic substitution affects reaction rates and equilibrium constants. ... These values are considered in relation to the vapor pressures of isotopic compds., the geologic abundance of C and O isotopes, the relative abundance of O isotopes in air and H2O, and variations in the at. ...

Giulia de Petris; Anna Troiani

2008-03-05T23:59:59.000Z

427

Definition: Isotopic Analysis- Rock | Open Energy Information  

Open Energy Info (EERE)

Isotopic Analysis- Rock Isotopic Analysis- Rock Jump to: navigation, search Dictionary.png Isotopic Analysis- Rock Isotopes are atoms of the same element that have different numbers of neutrons. An isotopic analysis looks at a particular isotopic element(s) in a given system, while the conditions which increase/decrease the number of neutrons are well understood and measurable.[1] View on Wikipedia Wikipedia Definition References ↑ http://wwwrcamnl.wr.usgs.gov/isoig/isopubs/itchch2.html Ret LikeLike UnlikeLike You like this.Sign Up to see what your friends like. rieved from "http://en.openei.org/w/index.php?title=Definition:Isotopic_Analysis-_Rock&oldid=687702" Category: Definitions What links here Related changes Special pages Printable version Permanent link Browse properties

428

Diffusion in single crystals of melilite: I. Oxygen  

SciTech Connect (OSTI)

Diffusion profiles of {sup 18}O tracer in single crystals of gehlenite and akermanite following annealing at 1,000{degree}-1,300{degree}C have been determined by a depth-profiling technique using secondary ion mass spectrometry. From the {sup 18}O depth profiling the lattice diffusion coefficients for oxygen along the crystallographic axes in gehlenite and akermanite, D{sup 1}{sub geh}//c, D{sup 1}{sub ak}//{alpha} and D{sup 1}{sub ak}//c, respectively, are given by three different equations. Present results are two to four orders of magnitude lower than those previously reported for melilite solid solutions. These high diffusion rates in melilite solid solutions and the heterogeneous distribution of O isotopes in the Allende Ca, Al-rich inclusions (CAIs) have been examined considering the contribution of fast diffusion along dislocations and possible changes in diffusion rate with gehlenite-akermanite ratios in melilite. For this purpose, diffusion coefficients of O along dislocations were calculated by analyzing tailing of the O-diffusion profiles. From the effective diffusion rate in melilite solid solution obtained by lattice and dislocation diffusion rates, it is unlikely that the O-isotope differences in the Allende CAI minerals are the result of diffusion processes during a postcrystallization thermal event.

Yurimoto, Hisayoshi (Univ. of Tsukuba, Ibaraki (Japan)); Morioka, Masana (Univ. of Tokyo (Japan)); Nagasawa, Hiroshi (Gakushuin Univ., Tokyo (Japan))

1989-09-01T23:59:59.000Z

429

Quantifying the areal extent and dissolved oxygen concentrations of Archean oxygen oases.  

E-Print Network [OSTI]

??Several lines of evidence indicate that the advent of oxygenic photosynthesis preceded the oxygenation of the atmosphereperhaps by as much as 300 million years. The (more)

Olson, Stephanie

2013-01-01T23:59:59.000Z

430

Neutron Stimulated Emission Computed Tomography of Stable Isotopes  

E-Print Network [OSTI]

Neutron Stimulated Emission Computed Tomography of Stable Isotopes Carey E. Floyd Jr.*ab , Calvin North Carolina Keywords: imaging, neutrons, tomography, spectroscopy ABSTRACT Here we report on the development of a new molecular imaging technique using inelastic scattering of fast neutrons. Earlier studies

431

Isotope Effects and Medium Effects on Sulfuryl Transfer Reactions  

Science Journals Connector (OSTI)

Kinetic isotope effects and medium effects have been measured for sulfuryl-transfer reactions of the sulfate ester p-nitrophenyl sulfate (pNPS). The results are compared to those from previous studies of phosphoryl transfer, a reaction with mechanistic ...

Richard H. Hoff; Paul Larsen; Alvan C. Hengge

2001-08-30T23:59:59.000Z

432

Kinetic Isotope Effects in Cycloreversion of Rhenium (V) Diolates  

Science Journals Connector (OSTI)

The isotope effects were all calculated from these ratios according to the equation25 (F = extent of reaction; R = isotopic ratio vs reference at extent of reaction F; R0 = initial isotopic ratio vs reference). ... The magnitudes of small kinetic isotope effects (KIEs) are amplified in the isotopic compn. of starting materials recovered from reactions taken to high conversions. ... The magnitudes of small kinetic isotope effects (KIEs) are amplified in the isotopic compn. of starting materials recovered from reactions taken to high conversions. ...

Kevin P. Gable; Fedor A. Zhuravlev

2002-03-21T23:59:59.000Z

433

Accretionary wedge harzburgite serpentinization and rodingitization constrained by perovskite U/Pb SIMS age, trace elements and Sm/Nd isotopes: Case study from the Western Carpathians, Slovakia  

Science Journals Connector (OSTI)

Abstract Perovskite-bearing harzburgites occur in a mlange type blueschist-bearing accretionary wedge complex of the Inner Western Carpathians Meliata Unit in Slovakia. Although dark rounded, slightly hydrated relic cores of harzburgite boulders are perovskite-free, perovskite (Prv) occurrence in the surrounding serpentinites and rodingites enabled dating of hydration, resulting in two metamorphicmetasomatic Prv generations. Perovskite (1) grows parallel to relic clinopyroxene exsolution lamellae or forms randomly oriented grain clusters in serpentinized orthopyroxene (Opx1) porphyroclasts, often accompanied by tiny andradite lamellae clusters, or it is partly replaced by Ti-andradite. Perovskite crystallization indicates evolving rodingitization fluids pervading the boundary between the harzburgite cores and Prv-free serpentinite. This strictly limited occurrence of Prv (1) within a 1 to 20-cm across-zone implies slightly postponed Prv crystallization to serpentinization by LREE(Ce,La), Ca2+, Ti/Fe3+-enriched aqueous fluids. A grain scale metasomatic mechanism partitioned Ca and Ti from the host orthopyroxene porphyroclasts, spinel (Ti) and grain-boundary pervasive fluids to Prv. In contrast, Prv (2) occurs in a 1 to 3cm across chlorite-rich blackwall zone between hosting serpentinite and rodingite veins, thus indicating channelled rodingitization fluid flow and accompanying hydraulic fracturing. Here, Prv (2) is ingrown by chlorite and apatite. Part of this Prv (2) formed in a rodingite vein mineral assemblage composed of diopside, andradite, vesuvianite, epidote/zoisite, apatite and chlorite. Both perovskite 1 and 2 are replaced by pyrophanite along the grain rims and interiors; most likely via fluid-aided coupled dissolutionreprecipitation at increased SiFeMnAl element solubility in rodingitization fluids pervading serpentinized harzburgite. Both Prv generations, especially Prv (2), can be partly to almost totally replaced by (Ti-) Adr. Overgrowths of spinel by andradite are occasionally observed in contact zones between the serpentinites and rodingites. LA-ICP-MS study revealed strong depletion in LREE from Prv (1) to Prv (2), and a more typically positive Eu anomaly for Prv (2). Our spider diagram depicts relative enrichment in U, Nb, La, Ce, Pr, Nd, and decreased Rb, Ba, Th, Ta, Pb, Sr, Zr in both Prv generations. The U/Pb SIMS concordia ages of Prv (1) from 3 samples range from 1371Ma to 1351Ma, with a mean of 135.60.58Ma, while Prv (2) was dated at 133.75.4Ma. Such negligible age differences imply a relatively short-lived rodingitization event responsible for crystallization of both Prv generations. The 143Nd/144Nd mean value of Prv (1) is 0.5121530.000017 by LA-MC-ICP-MS, thus corresponding to the initial ?Nd(t=135)=?8.20.4 (math's mean). This suggests that the subducted and dehydrated continental crust was the main source of the interactive fluids which initiated serpentinization and rodingitization in the Neotethyan Meliatic accretionary wedge following closure of the MeliataHallstatt Triassic to Jurassic oceanic back-arc basin and the high-pressure metamorphism dated at ca. 160150Ma by 40Ar/39Ar.

Xian-Hua Li; Marin Puti; Yue-Heng Yang; Mat Koppa; Marian Dyda

2014-01-01T23:59:59.000Z

434

Interaction of mineral matter of coal with oxygen carriers in chemical-looping combustion (CLC)  

Science Journals Connector (OSTI)

Abstract The chemical-looping combustion (CLC) and chemical-looping with oxygen uncoupling (CLOU) processes are novel solutions for efficient combustion with direct separation of carbon dioxide. These processes use a metal oxide as an oxygen carrier to transfer oxygen from an air to a fuel reactor, where the fuel reacts with the solid oxygen carrier. When utilizing coal in CLC, the oxygen carrier particles could be affected through interaction with the ash-forming mineral matter found in coal, causing deactivation and/or agglomeration. In this work, possible interactions between minerals commonly encountered in coal and several promising oxygen carriers that are currently under investigation for their use in CLC are studied by both experiment and thermodynamic equilibrium calculations. Possible interaction was studied for both highly reducing and oxidizing conditions at 900C. Under highly reducing conditions pyrite was found to have by far the most deteriorating effect on the oxygen carrier particles, as the sulfur in the pyrite reacted with the oxygen carrier to form sulfides. Quartz and clay minerals were found to have a rather low influence on the oxygen carriers. Out of the oxygen carriers investigated, CuO/MgAl2O4 and the Mn3O4/ZrO2 oxygen carriers tended to be quite reactive towards mineral matter whereas ilmenite has been shown to be the most robust oxygen carrier. Although sulfur can clearly deactivate Ni, Cu and Mn based oxygen carriers under sub-stoichiometric conditions, when the fuel is converted fully to CO2 and H2O, sulfides are only expected for Ni-based oxygen carriers.

Martin Keller; Mehdi Arjmand; Henrik Leion; Tobias Mattisson

2014-01-01T23:59:59.000Z

435

Isotopic Analysis At Dixie Valley Geothermal Field Area (Kennedy & Van  

Open Energy Info (EERE)

Dixie Valley Geothermal Field Area (Kennedy & Van Dixie Valley Geothermal Field Area (Kennedy & Van Soest, 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Dixie Valley Geothermal Field Area (Kennedy & Van Soest, 2005) Exploration Activity Details Location Dixie Valley Geothermal Field Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful DOE-funding Unknown Notes Dixie Valley study suggests that helium isotopes may provide a new tool for mapping zones of deep permeability and therefore the potential for high fluid temperatures. The permeable zones are identified by local enrichments in 3He relative to a regional helium isotope trend. More work needs to be done, but it appears that helium isotopes may provide the best and perhaps

436

Tracking the Sources of Nitrate in Groundwater Using Coupled Nitrogen and Boron Isotopes:? A Synthesis  

Science Journals Connector (OSTI)

Studied were carried out in three different hydrogeological contexts in Francefractured bedrock (Arguenon, Brittany), deep alluvial groundwater (Pia, Pyrenees), and subsurface alluvial groundwater (Ile du Chambon, Allier)in order to determine whether, regardless of the hydrogeological context, the combined use of nitrogen and boron would allow both the identification of pollution sources and the semiquantification of their respective contributions to the observed NO3 levels in groundwater. ... For isotope measurements, the groundwater samples were collected in either 10-L jerry cans (for nitrogen isotopes determination) or 1-L bottles (for boron isotopes). ... The stable isotopes of the conservative element boron, 11B and 10B, have been employed as co-migrating isotopic tracers to trace potential sources of nitrate obsd. in groundwater pumped from a large capacity 0.167 m3/s irrigation well in the Avra Valley of southeastern Arizona. ...

David Widory; Emmanuelle Petelet-Giraud; Philippe Ngrel; Bernard Ladouche

2004-12-04T23:59:59.000Z

437

Microbial oceanography of anoxic oxygen minimum zones  

E-Print Network [OSTI]

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, ...

Ulloa, Osvaldo

438

The Role of Oxygen in Coal Gasification  

E-Print Network [OSTI]

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...

Klosek, J.; Smith, A. R.; Solomon, J.

439

Microchemical systems for singlet oxygen generation  

E-Print Network [OSTI]

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 ...

Hill, Tyrone F. (Tyrone Frank), 1980-

2008-01-01T23:59:59.000Z

440

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 ARRA-enabled upgrades enhance research capabilities STM images of the same TiO2(110) area upon O2 chemisorption...

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Strontium isotopic variations of Neoproterozoic seawater: Implications for crustal evolution  

SciTech Connect (OSTI)

The authors report high precision Sr isotopic data on carbonates from the Neoproterozoic Shaler Group, Victoria Island, Northwest Territories, Canada. Samples with low {sup 87}Rb/{sup 86}Sr ratios (<0.01) were selected for Sr isotopic analysis. {delta}{sup 18}O, Mn, Ca, Mg, and Sr data were used to recognize altered samples. The altered samples are characterized by high Mn/Sr ({ge}2) and variable {delta}{sup 18}O; most are dolomites. The data indicate that between ca. 790-850 Ma the {sup 87}Sr/{sup 86}Sr ratio of seawater varied between 0.70676 and 0.70561. The samples show smooth and systematic variation, with the lowest {sup 87}Sr/{sup 86}Sr value of 0.70561 at ca. 830 Ma. The low {sup 87}Sr/{sup 86}Sr ratio of carbonates from the lower parts of the section is similar to a value reported for one sample from the Adrar of Mauritania ({approx}900 Ma), West African Craton. Isotopic ratios from the upper part of the Shaler section are identical to values from the lower part of the Neoproterozoic Akademikerbreen Group, Spitsbergen. Although a paucity of absolute age determinations hinders attempts at the precise correlation of Neoproterozoic successions, it is possible to draw a broad outline of the Sr isotopic composition of seawater for this period. Data from this study and the literature are used to construct a curve of the {sup 87}Sr/{sup 86}Sr ratio of Neoproterozoic seawater. The Sr isotope composition of seawater reflects primarily the balance between continental Sr input through river input and mantle input via hydrothermal circulation of seawater through mid-ocean ridges. Coupling of Nd and Sr isotopic systems allows the authors to model changes in seafloor spreading rates (or hydrothermal flux) and continental erosion. The Sr hydrothermal flux and the erosion rate (relative to present-day value) are modeled for the period 500-900 Ma.

Asmerom, Y.; Jacobsen, S.B.; Knoll, A.H.; Butterfield, N.J. (Harvard Univ., Cambridge, MA (United States)); Swett, K. (Univ. of Iowa, Iowa City (United States))

1991-10-01T23:59:59.000Z

442

Fusion reactions with germanium isotopes  

Science Journals Connector (OSTI)

Measurements of the fusion of 16O and 27Al with a series of germanium isotopes are analyzed within a coupled-channels approach. It is found that couplings based interactions that are linear in the deformation amplitudes are insufficient in reproducing the data. In order to obtain reasonable fits, it is necessary also to include couplings based on quadratic interactions. The analysis suggests that the nuclear radius of 72Ge is significantly smaller than predicted from a smooth interpolation between other germanium isotopes. The large prolate deformation of 74Ge, which has been proposed as the preferred solution to measurements of the quadrupole moment of the 2+ state, is not supported by the analysis; the near spherical solution is more likely.

H. Esbensen

2003-09-04T23:59:59.000Z

443

Global Security, Medical Isotopes, and Nuclear Science  

SciTech Connect (OSTI)

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.

Ahle, L E

2007-09-17T23:59:59.000Z

444

Composite oxygen ion transport element  

SciTech Connect (OSTI)

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.

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

445

Catalyst containing oxygen transport membrane  

SciTech Connect (OSTI)

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.

Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

2012-12-04T23:59:59.000Z

446

Magnesium Isotopes in Halo Stars  

E-Print Network [OSTI]

We have determined Mg isotope ratios in halo field dwarfs and giants in the globular cluster M71 based on high S/N high spectral resolution (R = 10$^5$) Keck HIRES spectra. Unlike previous claims of an important contribution from intermediate-mass AGB stars to the Galactic halo, we find that our $^{26}$Mg/$^{24}$Mg ratios can be explained by massive stars.

Jorge Melendez; Judith G. Cohen

2007-08-29T23:59:59.000Z

447

Frequency effects on the production of reactive oxygen species in atmospheric radio frequency helium-oxygen discharges  

SciTech Connect (OSTI)

Several experimental and computational studies have shown that increasing frequency can effectively enhance the discharge stability in atmospheric radio-frequency (rf) discharges, but the frequency effects on the reactivity of rf discharges, represented by the densities of reactive oxygen species (ROS), are still far from fully understood. In this paper, a one-dimensional fluid model with 17 species and 65 reactions taken into account is used to explore the influences of the driving frequency on the production and destruction of ROS in atmospheric rf helium-oxygen discharges. From the computational results, with an increase in the frequency the densities of ROS decrease always at a constant power density, however, in the relatively higher frequency discharges the densities of ROS can be effectively improved by increasing the input power density with an expanded oxygen admixture range, while the discharges operate in the {alpha} mode, and the numerical data also show the optimal oxygen admixture for ground state atomic oxygen, at which the peak atomic oxygen density can be obtained, increases with the driving frequency.

Zhang, Yuantao T.; He Jin [Shandong Provincial Key Lab of UHV Technology and Gas Discharge Physics, School of Electrical Engineering, Shandong University, Jinan, Shandong Province 250061 (China)

2013-01-15T23:59:59.000Z

448

Oxygen Detection via Nanoscale Optical Indicators  

E-Print Network [OSTI]

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

Ghosh, Ruby N.

449

8, 22252248, 2008 Detection of oxygen  

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

450

Oxygen and Nitrogen Contamination During Arc Welding  

E-Print Network [OSTI]

) ) : ,- Oxygen and Nitrogen Contamination During Arc Welding T. W. Eagar Department of }faterials, mechanisms, and expected levels of oxygen and nitrogen contamination during gas tungsten arc, gas metal arc indicating the importance of dec9mposition of SiOz into silicon monoxide and oxygen are presented, indicating

Eagar, Thomas W.

451

RADIOCHEMICAL STUDIES OF NEUTRON DEFICIENT ACTINIDE ISOTOPES  

E-Print Network [OSTI]

Column Chromatography 2. Americium and Curium t IV. COUNTINGberkellum, curium, and americium compared with theirfor the separation of curium and americium (trans- plutonium

Williams, Kimberly Eve

2011-01-01T23:59:59.000Z

452

The Mechanisms of Oxygen Reduction and Evolution Reactions in...  

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

Mechanisms of Oxygen Reduction and Evolution Reactions in Nonaqueous Lithium-Oxygen Batteries. The Mechanisms of Oxygen Reduction and Evolution Reactions in Nonaqueous...

453

Oxygen consumption of bovine granulosa cells in vitro.  

E-Print Network [OSTI]

??The oxygen consumption rate of granulosa cells is considered to be a key determinant of oocyte oxygenation in follicles. The oxygen status of the oocyte (more)

Li, Dongxing

2012-01-01T23:59:59.000Z

454

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

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

Dependency of Thin Film Samaria Doped Ceria for Oxygen Sensing . Thickness Dependency of Thin Film Samaria Doped Ceria for Oxygen Sensing . Abstract: High temperature oxygen...

455

Nuclear Energy Protocol for Research Isotopes Owen Lowe  

Broader source: Energy.gov (indexed) [DOE]

Protocol for Protocol for Research Isotopes Owen Lowe Office of Isotopes for Medicine and Science Office of Nuclear Energy, Science and Technology April 16, 2002 Isotopes for Life Isotopes for Life Isotopes for Life Office of Nuclear Energy, Science and Technology Lowe/April16_02 NEPRI to NERAC.ppt (2) Nuclear Energy Protocol For Research Isotopes Nuclear Energy Protocol For Research Isotopes Why NEPRI? 6 NEPRI implements DOE funding priorities for fiscal year 2003 6 NEPRI will * Bring order to DOE's responses to requests for research isotopes * Introduce a high-quality peer review to the selection of research isotopes * Enable DOE to concentrate on operating its unique isotope production facilities Isotopes for Life Isotopes for Life Isotopes for Life Office of Nuclear Energy, Science and Technology

456

Singlet Oxygen Singlet oxygen generation and detection are growing fields with applications in such areas as  

E-Print Network [OSTI]

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

Wells, Mathew G. - Department of Physical and Environmental Sciences, University of Toronto

457

Oxygen permeation in bismuth-based materials part I: Sintering and oxygen permeation fluxes  

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

458

Oxygen Distribution in the Macaque Retina Jameel Ahmed* Rod D. Braun,^ Robert Dunn, Jr. * and Robert A. Linsenmeier*X  

E-Print Network [OSTI]

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

Linsenmeier, Robert

459

Strategic Isotope Production | ornl.gov  

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

Strategic Isotope Strategic Isotope Production SHARE Strategic Isotope Production Typical capsules used in the transport of 252Cf source material inside heavily shielded shipping casks. ORNL's unique facilities at the High Flux Isotope Reactor (HFIR), Radiochemical Engineering Development Center (REDC), Irradiated Fuels Examination Laboratory (IFEL), and Irradiated Materials Examination Testing facility (IMET) are routinely used in the production, purification, packaging, and shipping of a number of isotopes of national importance, including: 75Se, 63Ni, 238Pu, 252Cf, and others. The intense neutron flux of the HFIR (2.0 x 1015 neutrons/cm²·s) permits the rapid formation of such isotopes. These highly irradiated materials are then processed and packaged for shipping using the facilities at the REDC, IFEL, and IMET.

460

Electromagnetic Isotope Separation Lab (EMIS) | ORNL  

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

Electromagnetic Isotope Separation Lab Electromagnetic Isotope Separation Lab May 30, 2013 ORNL established the Stable Isotope Enrichment Laboratory (SIEL) as part of a project funded by the DOE Office of Science, Nuclear Physics Program to develop a modernized electromagnetic isotope separator (EMIS), optimized for separation of a wide range of stable isotopes. The SIEL is located in the Building 6010 Shield Test Station, space formerly allocated to the Oak Ridge Electron Linear Accelerator, on the main campus of ORNL. ORNL staff have designed and built a nominal 10 mA ion current EMIS (sum of all isotopes at the collector) in the SIEL. This EMIS is currently being tested to determine basic performance metrics such as throughput and enrichment factor per pass. This EMIS unit and space will be used to

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Stable Isotope Dynamics in Cownose Rays (Rhinoptera bonasus) within the Northwestern Gulf of Mexico  

E-Print Network [OSTI]

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...

St. Clair, Katherine I

2014-07-25T23:59:59.000Z

462

Stable nitrogen isotope measurements of marine bacterial proteins and nucleic acids: tracers of microbial activity  

E-Print Network [OSTI]

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...

Kovacs, Jeffrey Paul

2012-06-07T23:59:59.000Z

463

A stable isotope stratigraphy for the Axel Heiberg Fossil Forest and its application to Eocene climate  

E-Print Network [OSTI]

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 ...

Byrne, Monica C. (Monica Catherine)

2005-01-01T23:59:59.000Z

464

Tracing dust provenance, cycling, and history in the Wasatch Mountains using strontium isotopes and tree rings.  

E-Print Network [OSTI]

??To further our understanding of dust cycling from the Great Basin to the Rocky Mountains, this study uses strontium concentrations and isotopes (87Sr/86Sr) to investigate (more)

Miller, Olivia Leigh

2013-01-01T23:59:59.000Z

465

Kinetics of Precursor Labeling in Stable Isotope Labeling in Cell Cultures (SILAC) Experiments  

Science Journals Connector (OSTI)

Recent advances in mass spectrometry have enabled proteome-wide analyses of cellular protein turnover. These studies have been greatly propelled by the development of stable isotope labeling in cell cultures (SILAC), a set of standardized protocols, ...

Tian Zhang; John C. Price; Eslam Nouri-Nigjeh; Jun Li; Marc K. Hellerstein; Jun Qu; Sina Ghaemmaghami

2014-10-09T23:59:59.000Z

466

E-Print Network 3.0 - age sm-nd isotopic Sample Search Results  

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

Sm-Nd isotopic study of the Martian meteorite Zagami LARS E. BORG,1, * JENNIFER E... --Uranium-lead, Rb-Sr, and Sm-Nd ... Source: Asmerom, Yemane - Department of Earth and...

467

Hydrogen absorption characteristics of oxygen-stabilized rare-earth iron intermetallic compounds  

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

468

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]

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 ...

Harris, Eliza

469

Development of high through-put Sr isotope analysis for monitoring reservoir integrity for CO{sub 2} storage.  

SciTech Connect (OSTI)

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.

Wall, Andy; Jain, Jinesh; Stewart, Brian; Capo, Rosemary; Hakala, Alexandra J.; Hammack, Richard; Guthrie, George

2012-01-01T23:59:59.000Z

470

Oxygen abundance in the Sloan Digital Sky Survey  

E-Print Network [OSTI]

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.

F. Shi; X. Kong; F. Z. Cheng

2006-03-10T23:59:59.000Z

471

Enforcement Letter, International Isotopes Idaho Inc - August...  

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

Isotopes Idaho, Inc. related to the Relocation of an Irradiated Pellet at the Test Reactor Area Hot Cell Facility at the Idaho National Engineering and Environmental...

472

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.

473

Category:Isotope Geothermometry | Open Energy Information  

Open Energy Info (EERE)

Login | Sign Up Search Category Edit History Facebook icon Twitter icon Category:Isotope Geothermometry Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home...

474

Integration of Nontraditional Isotopic Systems Into Reaction...  

Broader source: Energy.gov (indexed) [DOE]

minerals in geothermal systems (feldspars, epidote, and calcite) often control fracture permeability changes. Measurements of Ca and Sr isotopic fractionation at high...

475

Science with Beams of Radioactive Isotopes  

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

2015 The International Chemical Congress of Pacific Basin Societies Science with Beams of Radioactive Isotopes ( 340) Honolulu, Hawaii, USA December 15-20, 2015 Science...

476

Integration of Nontraditional Isotopic Systems Into Reaction...  

Broader source: Energy.gov (indexed) [DOE]

of EGS For Exploration, Evaluation of Water-Rock Interaction, and Impacts of Water Chemistry on Reservoir Sustainability Integration of Nontraditional Isotopic Systems Into...

477

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

E-Print Network [OSTI]

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

Pennycook, Steve

478

An inverse approach to understanding benthic oxygen isotope records from the last deglaciation  

E-Print Network [OSTI]

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 ...

Amrhein, Daniel Edward

2014-01-01T23:59:59.000Z

479

Carbon-14 production compared to oxygen isotope records from Camp Century, Greenland and Devon Island, Canada  

Science Journals Connector (OSTI)

Carbon-14 production rate variations that are not explainable by geomagnetic changes are thought to be in antiphase with solar activity and as such should be in antiphase with paleotemperature records or proxy te...

David Andrew Fisher

1982-01-01T23:59:59.000Z

480

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

E-Print Network [OSTI]

variability of regional Holocene climate modification within the Rocky Mountain region. Herein we show

Hren, Michael

Note: This page contains sample records for the topic "oxygen isotope study" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.