Powered by Deep Web Technologies
Note: This page contains sample records for the topic "oxygen isotope evidence" 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.


1

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

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

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

2

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

3

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

4

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

E-Print Network [OSTI]

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

5

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

6

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

SciTech Connect (OSTI)

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

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

1993-02-01T23:59:59.000Z

7

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

8

Oxygen isotope exchange between water and semiquinones  

SciTech Connect (OSTI)

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

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

1988-09-14T23:59:59.000Z

9

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

10

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.

11

Lead and strontium isotopic evidence for crustal interaction...  

Open Energy Info (EERE)

and strontium isotopic evidence for crustal interaction and compositional zonation in the source regions of Pleistocene basaltic and rhyolitic magmas of the Coso volcanic field,...

12

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

13

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.

14

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

15

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...

16

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

17

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

18

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.

19

Constraints on Hadean zircon protoliths from oxygen isotopes, Ti-thermometry, and rare earth elements  

E-Print Network [OSTI]

, and analysis of zircon/melt partitioning of rare earth elements (REEs) provide mutually consistent lines, 3 tables. Keywords: Hadean; crust; ion microprobe; oxygen; zircon thermometry; rare earth elements oxygen isotopes, Ti-thermometry, and rare earth elements, Geochem. Geophys. Geosyst., 8, Q06014, doi:10

20

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

Open Energy Info (EERE)

boiling or by isotopic exchange at low waterrock ratios in new fractures. The mineralogy and apparent 18O enrichments of hydrothermal fracture-filling minerals are...

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

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

22

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.

23

Rare sulfur and triple oxygen isotope geochemistry of volcanogenic sulfate aerosols  

E-Print Network [OSTI]

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

Bindeman, Ilya N.

24

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...

25

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

E-Print Network [OSTI]

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

Stoner, Joseph

26

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 and in the case of the calcium isotopes at ${}^{60}$Ca. To produce such behavior, the resulting symmetry energy must be soft, with predicted values for the symmetry energy and its slope at saturation density being $J\\!=\\!(30.92\\pm0.47)$ MeV and $L\\!=\\!(51.0\\pm1.5)$ MeV, respectively. As a consequence, the neutron-skin thickness of ${}^{208}$Pb is rather small: $R_{\\rm skin}^{208}\\!=\\!(0.161\\pm0.011)$ fm. This same model - labelled "FSUGarnet" - predicts $R_{1.4}\\!=\\!(13.1\\pm0.1)$ km for the radius of a "canonical" 1.4$M_{\\odot}$ neutron star, yet is also able to support a two-solar-mass neutron star.

Wei-Chia Chen; J. Piekarewicz

2015-03-10T23:59:59.000Z

27

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

28

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.

29

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

30

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

SciTech Connect (OSTI)

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

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

2012-11-01T23:59:59.000Z

31

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

E-Print Network [OSTI]

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

32

Vegetation succession and carbon sequestration in a coastal wetland in northwest Florida: Evidence from carbon isotopes  

E-Print Network [OSTI]

Vegetation succession and carbon sequestration in a coastal wetland in northwest Florida: Evidence from carbon isotopes Yonghoon Choi and Yang Wang Department of Geological Sciences, Florida State. Measurements of stable carbon isotopic ratios as well as carbon (C), nitrogen (N), and phosphorus (P) contents

Wang, Yang

33

Mercury methylation in oxygen deficient zones of the oceans: No evidence for the predominance of anaerobes  

E-Print Network [OSTI]

Mercury methylation in oxygen deficient zones of the oceans: No evidence for the predominance Keywords: Methylmercury Oxygen minimum zone Arabian Sea Equatorial Eastern Pacific Mercury methylation Although a large fraction of the world's population is exposed to mercury through consumption of marine

Morel, François M. M.

34

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...

35

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

E-Print Network [OSTI]

(HCO3 2-, CO 3 2-, and CO2(aq)) were investigated at 15, 25, and 40 (degrees)C. To investigate oxygen isotope exchange between HCO3 2-, CO 3 -2, and H2O, NaHCO3 solutions were prepared and the pH was adjusted over a range of 2 to 12 by the addition...

Beck, William Cory

2004-11-15T23:59:59.000Z

36

Phosphorus dynamics in soils irrigated with reclaimed waste water or fresh water --A study using oxygen isotopic composition of phosphate  

E-Print Network [OSTI]

sludge) fertilization. Water scarcity in arid places (like Israel) has led to the use of reclaimed wastePhosphorus dynamics in soils irrigated with reclaimed waste water or fresh water -- A study using fractionation Oxygen isotopes Reclaimed waste water Transformations of phosphate (Pi) in different soil

Paytan, Adina

37

Strontium isotope evidence of Neanderthal mobility at the site of Lakonis, Greece using laser-ablation PIMMS  

E-Print Network [OSTI]

Strontium isotope evidence of Neanderthal mobility at the site of Lakonis, Greece using laser the measurement of strontium isotope ratios in tooth enamel using laser- ablation, which allows us to use much in a coastal limestone cave, yet the strontium isotope values indicate the enamel was formed while

Smith, Tanya M.

38

EVIDENCE FOR MAGNESIUM ISOTOPE HETEROGENEITY IN THE SOLAR PROTOPLANETARY DISK  

SciTech Connect (OSTI)

With a half-life of 0.73 Myr, the {sup 26}Al-to-{sup 26}Mg decay system is the most widely used short-lived chronometer for understanding the formation and earliest evolution of the solar protoplanetary disk. However, the validity of {sup 26}Al-{sup 26}Mg ages of meteorites and their components relies on the critical assumption that the canonical {sup 26}Al/{sup 27}Al ratio of {approx}5 x 10{sup -5} recorded by the oldest dated solids, calcium-aluminium-rich inclusions (CAIs), represents the initial abundance of {sup 26}Al for the solar system as a whole. Here, we report high-precision Mg-isotope measurements of inner solar system solids, asteroids, and planets demonstrating the existence of widespread heterogeneity in the mass-independent {sup 26}Mg composition ({mu}{sup 26}Mg*) of bulk solar system reservoirs with solar or near-solar Al/Mg ratios. This variability may represent heterogeneity in the initial abundance of {sup 26}Al across the solar protoplanetary disk at the time of CAI formation and/or Mg-isotope heterogeneity. By comparing the U-Pb and {sup 26}Al-{sup 26}Mg ages of pristine solar system materials, we infer that the bulk of the {mu}{sup 26}Mg* variability reflects heterogeneity in the initial abundance of {sup 26}Al across the solar protoplanetary disk. We conclude that the canonical value of {approx}5 x 10{sup -5} represents the average initial abundance of {sup 26}Al only in the CAI-forming region, and that large-scale heterogeneity-perhaps up to 80% of the canonical value-may have existed throughout the inner solar system. If correct, our interpretation of the Mg-isotope composition of inner solar system objects precludes the use of the {sup 26}Al-{sup 26}Mg system as an accurate early solar system chronometer.

Larsen, Kirsten K.; Trinquier, Anne; Paton, Chad; Schiller, Martin; Wielandt, Daniel; Connelly, James N.; Nordlund, Ake; Krot, Alexander N.; Bizzarro, Martin [Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Copenhagen DK-1350 (Denmark); Ivanova, Marina A. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow 119991 (Russian Federation)

2011-07-10T23:59:59.000Z

39

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. Navrátil

2014-12-01T23:59:59.000Z

40

Evidence for a mantle component shown by rare gases, C and N isotopes in polycrystalline diamonds from Orapa (Botswana)  

E-Print Network [OSTI]

Evidence for a mantle component shown by rare gases, C and N isotopes in polycrystalline diamonds. Farley Abstract In an attempt to constrain the origin of polycrystalline diamond, combined analyses in the source of the polycrystalline diamonds from Orapa. The y13 C and y15 N isotopic values of À1.04 to À9.79x

Cartigny, Pierre

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

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

42

Strontium isotope evidence for migration in late Pleistocene Rangifer: Implications for Neanderthal hunting strategies at the Middle Palaeolithic site of Jonzac, France  

E-Print Network [OSTI]

Strontium isotope evidence for migration in late Pleistocene Rangifer: Implications for Neanderthal, it is essential to understand the behavioural ecology of their prey. Here, we present strontium isotope data from

43

ZIRCONIUM—HAFNIUM ISOTOPE EVIDENCE FROM METEORITES FOR THE DECOUPLED SYNTHESIS OF LIGHT AND HEAVY NEUTRON-RICH NUCLEI  

SciTech Connect (OSTI)

Recent work based on analyses of meteorite and terrestrial whole-rock samples showed that the r- and s- process isotopes of Hf were homogeneously distributed throughout the inner solar system. We report new Hf isotope data for Calcium-Aluminum-rich inclusions (CAIs) of the CV3 carbonaceous chondrite Allende, and novel high-precision Zr isotope data for these CAIs and three carbonaceous chondrites (CM, CO, CK). Our Zr data reveal enrichments in the neutron-rich isotope {sup 96}Zr (?1? in {sup 96}Zr/{sup 90}Zr) for bulk chondrites and CAIs (?2?). Potential isotope effects due to incomplete sample dissolution, galactic and cosmic ray spallation, and the nuclear field shift are assessed and excluded, leading to the conclusion that the {sup 96}Zr isotope variations are of nucleosynthetic origin. The {sup 96}Zr enrichments are coupled with {sup 50}Ti excesses suggesting that both nuclides were produced in the same astrophysical environment. The same CAIs also exhibit deficits in r-process Hf isotopes, which provides strong evidence for a decoupling between the nucleosynthetic processes that produce the light (A ? 130) and heavy (A > 130) neutron-rich isotopes. We propose that the light neutron-capture isotopes largely formed in Type II supernovae (SNeII) with higher mass progenitors than the supernovae that produced the heavy r-process isotopes. In the context of our model, the light isotopes (e.g. {sup 96}Zr) are predominantly synthesized via charged-particle reactions in a high entropy wind environment, in which Hf isotopes are not produced. Collectively, our data indicates that CAIs sampled an excess of materials produced in a normal mass (12-25 M{sub ?}) SNII.

Akram, W.; Schönbächler, M. [School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Sprung, P. [Institut für Planetologie, Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster (Germany); Vogel, N. [Institute for Geochemistry and Petrology, ETH, Clausiusstrasse 25, 8092 Zürich (Switzerland)

2013-11-10T23:59:59.000Z

44

Evidence for Thiol-Dependent Production of Oxygen Radicals by 4-Methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione  

E-Print Network [OSTI]

to a peroxide species that undergoes a trace metal-catalyzed, Fenton-type reaction to generate oxygen radicalsEvidence for Thiol-Dependent Production of Oxygen Radicals by 4-Methyl-5-pyrazinyl-3H-1,2-dithiole the conversion of molecular oxygen to reactive oxygen radicals. Using a plasmid-based assay that monitors DNA

Gates, Kent. S.

45

Isotopic evidence for neogene hominid paleoenvironments in the Kenya Rift Valley  

SciTech Connect (OSTI)

Bipedality, the definitive characteristic of the earliest hominids, has been regarded as an adaptive response to a transition from forested to more-open habitats in East Africa sometime between 12 million and 5 million years ago. Analyses of the stable carbon isotopic composition ([delta][sup 13]C) of paleosol carbonate and organic matter from the Tugen Hills succession in Kenya indicate that a heterogeneous environment with a mix of C3 and C4 plants has persisted for the last 15.5 million years. Open grasslands at no time dominated this portion of the rift valley. The observed [delta][sup 13]C values offer no evidence for a shift from more-closed C3 environments to C4 grasslands habitats. If hominids evolved in East Africa during the Late Miocene, they did so in an ecologically diverse setting.

Kingston, J.D.; Hill, A. (Yale Univ., New Haven, CT (United States)); Marino, B.D. (Harvard Univ., Cambridge, MA (United States))

1994-05-13T23:59:59.000Z

46

Seismic evidence of up to 200 m lake-level change in Southern Patagonia since Marine Isotope Stage 4  

E-Print Network [OSTI]

Seismic evidence of up to 200 m lake-level change in Southern Patagonia since Marine Isotope Stage Laguna Potrok Aike is located north of the Strait of Magellan (south- eastern Patagonia). Seismic, Patagonia, seismic reflection profiles. INTRODUCTION During the past decade, several studies have shown

Gilli, Adrian

47

Isotopic evidence of a near surface history for the source rocks of the central Coast Plutonic Complex, British Columbia, Canada  

E-Print Network [OSTI]

Isotopic evidence of a near surface history for the source rocks of the central Coast Plutonic portion of the source rocks resided at near surface levels at some time prior to burial and partial an evolved crustal source. We argue that these data indicate that the rocks that formed the source region

Wetmore, Paul H.

48

Isotopic Evidence of a Near Surface History for the Source Rocks of the Central Coast Mountains Batholith, British  

E-Print Network [OSTI]

Isotopic Evidence of a Near Surface History for the Source Rocks of the Central Coast Mountains from 322 Ma to ~50 Ma indicate that the source regions for these rocks were relatively uniform and typical for island arcs around the Pacific. Initial whole-rock 87 Sr/86 Sr range from 0.7032 up to 0

Wetmore, Paul H.

49

Isotopic evidence for source changes of nitrate in rain at Bermuda Meredith Galanter Hastings and Daniel M. Sigman  

E-Print Network [OSTI]

), or nitrate (NO3 Ã? ), is a significant contributor to acid rain, an important species in marineIsotopic evidence for source changes of nitrate in rain at Bermuda Meredith Galanter Hastings O is 68.6% and 76.9% (versus Vienna Standard Mean Ocean Water). The few cool season rain events

Sigman, Daniel M.

50

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

E-Print Network [OSTI]

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

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

2007-01-12T23:59:59.000Z

51

Oxygen Isotope Evidence For Past And Present Hydrothermal Regimes Of Long  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth'sOklahoma/GeothermalOrange County is aOrmesa IOvonic BatteryValley Caldera,

52

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

53

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

54

Tracing Paleoclimate over the Past 25,000 Years Using Evidence from Radiogenic Isotopes  

E-Print Network [OSTI]

The objective of this dissertation is to apply radiogenic isotopes extracted from marine sediments to investigate aspects of global climate change over the past 25 kyr, especially ocean and atmospheric circulation, continental aridity, and hydrology...

Xie, Ruifang

2013-04-30T23:59:59.000Z

55

Oxygen abundances in the Galactic Bulge: evidence for fast chemical enrichment  

E-Print Network [OSTI]

AIMS: We spectroscopically characterize the Galactic Bulge to infer its star formation timescale, compared to the other Galactic components, through the chemical signature on its individual stars. METHODS: We derived iron and oxygen abundances for 50 K giants in four fields towards the Galactic bulge. High resolution (R=45,000) spectra for the target stars were collected with FLAMES-UVES at the VLT. RESULTS: Oxygen, as measured from the forbidden line at 6300 \\AA, shows a well-defined trend with [Fe/H], with [O/Fe] higher in bulge stars than in thick disk ones, which were known to be more oxygen enhanced than thin disk stars. CONCLUSIONS: These results support a scenario in which the bulge formed before and more rapidly than the disk, and therefore the MW bulge can be regarded as a prototypical old spheroid, with a formation history similar to that of early-type (elliptical) galaxies.

M. Zoccali; A. Lecureur; B. Barbuy; V. Hill; A. Renzini; D. Minniti; Y. Momany; A. Gomez; S. Ortolani

2006-09-01T23:59:59.000Z

56

Enriched stable carbon isotopes in the pore waters of carbonate sediments dominated by seagrasses: Evidence  

E-Print Network [OSTI]

Enriched stable carbon isotopes in the pore waters of carbonate sediments dominated by seagrasses inorganic carbon (d13 C-DIC) were carried out in shallow water carbonate sediments of the Great Bahamas Bank (GBB) to further examine sediment­seagrass relationships and to more quantitatively describe the cou

Burdige, David

57

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

58

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.

59

MAGNESIUM ISOTOPE EVIDENCE FOR SINGLE STAGE FORMATION OF CB CHONDRULES BY COLLIDING PLANETESIMALS  

SciTech Connect (OSTI)

Chondrules are igneous spherical objects preserved in chondritic meteorites and believed to have formed during transient heating events in the solar protoplanetary disk. Chondrules present in the metal-rich CB chondrites show unusual chemical and petrologic features not observed in other chondrite groups, implying a markedly distinct formation mechanism. Here, we report high-precision Mg-isotope data for 10 skeletal olivine chondrules from the Hammadah al Hamra 237 (HH237) chondrite to probe the formation history of CB chondrules. The {sup 27}Al/{sup 24}Mg ratios of individual chondrules are positively correlated to their stable Mg-isotope composition (?{sup 25}Mg), indicating that the correlated variability was imparted by a volatility-controlled process (evaporation/condensation). The mass-independent {sup 26}Mg composition (?{sup 26}Mg*) of chondrules is consistent with single stage formation from an initially homogeneous magnesium reservoir if the observed ?{sup 25}Mg variability was generated by non-ideal Rayleigh-type evaporative fractionation characterized by a ? value of 0.5142, in agreement with experimental work. The magnitude of the mass-dependent fractionation (?300 ppm) is significantly lower than that suggested by the increase in {sup 27}Al/{sup 24}Mg values, indicating substantial suppression of isotopic fractionation during evaporative loss of Mg, possibly due to evaporation at high Mg partial pressure. Thus, the Mg-isotope data of skeletal chondrules from HH237 are consistent with their origin as melts produced in the impact-generated plume of colliding planetesimals. The inferred ?{sup 26}Mg* value of –3.87 ± 0.93 ppm for the CB parent body is significantly lower than the bulk solar system value of 4.5 ± 1.1 ppm inferred from CI chondrites, suggesting that CB chondrites accreted material comprising an early formed {sup 26}Al-free component.

Olsen, Mia B.; Schiller, Martin; Krot, Alexander N.; Bizzarro, Martin [Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Copenhagen DK-1350 (Denmark)] [Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Copenhagen DK-1350 (Denmark)

2013-10-10T23:59:59.000Z

60

Identification of an Archean marine oxygen oasis  

SciTech Connect (OSTI)

The early Earth was essentially anoxic. A number of indicators suggest the presence of oxygenic photosynthesis 2700 3000 million years (Ma) ago, but direct evidence for molecular oxygen (O2) in seawater has remained elusive. Here we report rare earth element (REE) analyses of 2800 million year old shallowmarine limestones and deep-water iron-rich sediments at Steep Rock Lake, Canada. These show that the seawater from which extensive shallow-water limestones precipitated was oxygenated, whereas the adjacent deeper waters where iron-rich sediments formed were not. We propose that oxygen promoted limestone precipitation by oxidative removal of dissolved ferrous iron species, Fe(II), to insoluble Fe(III) oxyhydroxide, and estimate that at least 10.25 M oxygen concentration in seawater was required to accomplish this at Steep Rock. This agrees with the hypothesis that an ample supply of dissolved Fe(II) in Archean oceans would have hindered limestone formation. There is no direct evidence for the oxygen source at Steep Rock, but organic carbon isotope values and diverse stromatolites in the limestones suggest the presence of cyanobacteria. Our findings support the view that during the Archean significant oxygen levels first developed in protected nutrient-rich shallow marine habitats. They indicate that these environments were spatially restricted, transient, and promoted limestone precipitation. If Archean marine limestones in general reflect localized oxygenic removal of dissolved iron at the margins of otherwise anoxic iron-rich seas, then early oxygen oases are less elusive than has been assumed.

Riding, Dr Robert E [University of Tennessee (UT); Fralick, Dr Philip [Lakehead University, Canada; Liang, Liyuan [ORNL

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

HETEROGENEOUS ISOTOPIC ANOMALIES OF SM AND GD IN THE NORTON COUNTY METEORITE: EVIDENCE FOR IRRADIATION FROM THE ACTIVE EARLY SUN  

SciTech Connect (OSTI)

Large and heterogeneous isotopic variations of {sup 150}Sm/{sup 149}Sm and {sup 158}Gd/{sup 157}Gd due to neutron capture reactions caused by cosmic-ray irradiation were found in chemical and mineral separates from the Norton County meteorite. The light-colored separates, consisting mainly of enstatite (Mg{sub 2}Si{sub 2}O{sub 6}), have a very large neutron fluence of 1.98 Multiplication-Sign 10{sup 17} n cm{sup -2}, which is 10 times higher than that of the whole rock. Furthermore, four chemical separates showed a large variation in neutron fluences, ranging from 1.82 Multiplication-Sign 10{sup 16} to 1.87 Multiplication-Sign 10{sup 17} n cm{sup -2}. The variable amounts of neutron fluences from a small single fragment of the Norton County meteorite cannot be simply explained by single-stage cosmic-ray irradiation in space. Rare earth element (REE) analyses revealed that the fractions with high neutron fluences have similar chemical properties to those in the early condensates in the solar system, showing depletions of Eu and Yb in their REE abundance patterns. The data provide evidence for an activity of the early Sun (T Tauri), suggesting the migration of early and intense irradiation materials into the Norton County meteorite's parent body.

Hidaka, Hiroshi; Kondo, Tomoyo [Department of Earth and Planetary Systems Science, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan); Yoneda, Shigekazu, E-mail: hidaka@hiroshima-u.ac.jp [Department of Science and Engineering, National Museum of Nature and Science, Tokyo 169-0073 (Japan)

2012-02-20T23:59:59.000Z

62

Cluster structures in Oxygen isotopes  

E-Print Network [OSTI]

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

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

2007-06-01T23:59:59.000Z

63

SILICON CARBIDE GRAINS OF TYPE C PROVIDE EVIDENCE FOR THE PRODUCTION OF THE UNSTABLE ISOTOPE {sup 32}Si IN SUPERNOVAE  

SciTech Connect (OSTI)

Carbon-rich grains are observed to condense in the ejecta of recent core-collapse supernovae (SNe) within a year after the explosion. Silicon carbide grains of type X are C-rich grains with isotopic signatures of explosive SN nucleosynthesis have been found in primitive meteorites. Much rarer silicon carbide grains of type C are a special sub-group of SiC grains from SNe. They show peculiar abundance signatures for Si and S, isotopically heavy Si, and isotopically light S, which appear to be in disagreement with model predictions. We propose that C grains are formed mostly from C-rich stellar material exposed to lower SN shock temperatures than the more common type X grains. In this scenario, extreme {sup 32}S enrichments observed in C grains may be explained by the presence of short-lived {sup 32}Si ({tau}{sub 1/2} = 153 yr) in the ejecta, produced by neutron capture processes starting from the stable Si isotopes. No mixing from deeper Si-rich material and/or fractionation of Si from S due to molecular chemistry is needed to explain the {sup 32}S enrichments. The abundance of {sup 32}Si in the grains can provide constraints on the neutron density reached during the SN explosion in the C-rich He shell material. The impact of the large uncertainty of the neutron capture cross sections in the {sup 32}Si region is discussed.

Pignatari, M.; Rauscher, T.; Thielemann, F.-K. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Zinner, E. [Laboratory for Space Sciences and the Physics Department, Washington University, St. Louis, MO 63130 (United States); Bertolli, M. G. [Theoretical Division (T-2), LANL, Los Alamos, NM 87545 (United States); Trappitsch, R. [Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637 (United States); Hoppe, P. [Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, D-55128 Mainz (Germany); Fryer, C. [Computational Physics and Methods (CCS-2), LANL, Los Alamos, NM 87545 (United States); Herwig, F. [Department of Physics and Astronomy, University of Victoria, Victoria, BC (Canada); Hirschi, R. [Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Timmes, F. X. [Joint Institute for Nuclear Astrophysics, Notre Dame, IN 46556 (United States)

2013-07-01T23:59:59.000Z

64

Nitrogen and Oxygen Abundance Variations in the Outer Ejecta of Eta Carinae: Evidence for Recent Chemical Enrichment  

E-Print Network [OSTI]

We present optical spectra of the ionized `Outer Ejecta' of Eta Carinae that reveal differences in chemical composition at various positions. In particular, young condensations just outside the dusty Homunculus Nebula show strong nitrogen lines and little or no oxygen -- but farther away, nitrogen lines weaken and oxygen lines become stronger. The observed variations in the apparent N/O ratio may signify either that the various blobs were ejected with different abundances, or more likely, that the more distant condensations are interacting with normal-composition material. The second hypothesis is supported by various other clues involving kinematics and X-ray emission, and would suggest that Eta Car is enveloped in a ``cocoon'' deposited by previous stellar-wind mass loss. In particular, all emission features where we detect strong oxygen lines are coincident with or outside the soft X-ray shell. In either case, the observed abundance variations suggest that Eta Car's ejection of nitrogen-rich material is a recent phenomenon -- taking place in just the last few thousand years. Thus, Eta Carinae may be at a critical stage of evolution when ashes of the CNO cycle have just appeared at its surface. Finally, these spectra reveal some extremely fast nitrogen-rich material, with Doppler velocities up to 3200 km/s, and actual space velocities that may be much higher. This is the fastest material yet seen in Eta Car's nebula, but with unknown projection angles its age is uncertain.

Nathan Smith; Jon A. Morse

2004-02-20T23:59:59.000Z

65

Silicon carbide grains of type C provide evidence for the production of the unstable isotope $^{32}$Si in supernovae  

E-Print Network [OSTI]

Carbon-rich grains are observed to condense in the ejecta of recent core-collapse supernovae, within a year after the explosion. Silicon carbide grains of type X are C-rich grains with isotpic signatures of explosive supernova nucleosynthesis have been found in primitive meteorites. Much rarer silicon carbide grains of type C are a special sub-group of SiC grains from supernovae. They show peculiar abundance signatures for Si and S, isotopically heavy Si and isotopically light S, which appear to to be in disagreement with model predictions. We propose that C grains are formed mostly from C-rich stellar material exposed to lower SN shock temperatures than the more common type X grains. In this scenario, extreme $^{32}$S enrichments observed in C grains may be explained by the presence of short-lived $^{32}$Si ($\\tau$$_{1/2}$ = 153 years) in the ejecta, produced by neutron capture processes starting from the stable Si isotopes. No mixing from deeper Si-rich material and/or fractionation of Si from S due to mole...

Pignatari, M; Bertolli, M G; Trappitsch, R; Hoppe, P; Rauscher, T; Fryer, C; Herwig, F; Hirschi, R; Timmes, F X; Thielemann, F -K

2013-01-01T23:59:59.000Z

66

Evidence of the production of hot hydrogen atoms in RF plasmas by catalytic reactions between hydrogen and oxygen species  

E-Print Network [OSTI]

Selective H-atom line broadening was found to be present throughout the volume (13.5 cm ID x 38 cm length) of RF generated H2O plasmas in a GEC cell. Notably, at low pressures (ca. hydrogen was 'hot' with energies greater than 40 eV with a pressure dependence, but only a weak power dependence. The degree of broadening was virtually independent of the position studied within the GEC cell, similar to the recent finding for He/H2 and Ar/H2 plasmas in the same GEC cell. In contrast to the atomic hydrogen lines, no broadening was observed in oxygen species lines at low pressures. Also, in control Xe/H2 plasmas run in the same cell at similar pressures and adsorbed power, no significant broadening of atomic hydrogen, Xe, or any other lines was observed. Stark broadening or acceleration of charged species due to high electric fields can not explain the results since (i) the electron density was insufficient by orders of magnitude, (ii) the RF field was essentially confined to the cathode fall region in contrast to the broadening that was independent of position, and (iii) only the atomic hydrogen lines were broadened. Rather, all of the data is consistent with a model that claims specific, predicted, species can act catalytically through a resonant energy transfer mechanism to create hot hydrogen atoms in plasmas.

Jonathan Phillips; Chun Ku Chen; Randell Mills

2004-02-06T23:59:59.000Z

67

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 atmosphere—perhaps by as much as 300 million years. The… (more)

Olson, Stephanie

2013-01-01T23:59:59.000Z

68

Isotopic Analysis-Fluid At Long Valley Caldera Geothermal Area...  

Open Energy Info (EERE)

1971) prior to analysis by mass spectrometry. Water samples were analyzed for their oxygen isotope ratios using the carbon dioxide-equilibration method. Waters analyzed from the...

69

RADIOCARBON AND STABLE ISOTOPE EVIDENCE OF DIETARY CHANGE FROM THE MESOLITHIC TO THE MIDDLE AGES IN THE IRON GATES: NEW RESULTS FROM LEPENSKI VIR  

E-Print Network [OSTI]

A previous radiocarbon dating and stable isotope study of directly associated ungulate and human bone samples from Late Mesolithic burials at Schela Cladovei in Romania established that there is a freshwater reservoir effect of approximately 500 yr...

Bonsall, C.; Cook, G. T.; Hedges, R. E. M.; Higham, T. F. G.; Pickard, C.; Radovanovic, I.

2004-01-01T23:59:59.000Z

70

Oxygen analyzer  

DOE Patents [OSTI]

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

Benner, William H. (Danville, CA)

1986-01-01T23:59:59.000Z

71

Isotope separation by selective photodissociation of glyoxal  

DOE Patents [OSTI]

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

Marling, John B. (Pleasanton, CA)

1976-01-01T23:59:59.000Z

72

Supersaturated N2O in a perennially ice-covered Antarctic lake: Molecular and stable isotopic evidence for a biogeochemical relict  

E-Print Network [OSTI]

Supersaturated N2O in a perennially ice-covered Antarctic lake: Molecular and stable isotopic Abstract The east lobe of Lake Bonney, a permanently ice-covered lake in the McMurdo Dry Valleys2O was produced via incomplete nitrification and has undergone virtually no subsequent consumption

Priscu, John C.

73

Oxygen analyzer  

DOE Patents [OSTI]

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

Benner, W.H.

1984-05-08T23:59:59.000Z

74

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

SciTech Connect (OSTI)

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

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

2008-11-17T23:59:59.000Z

75

Petrologic and stable isotopic evidence for reaction-enhanced fluid flow during metamorphism of Precambrian-Cambrian sedimentary rocks, Lone Mountain, Nevada  

SciTech Connect (OSTI)

Upper Precambrian to Cambrian sedimentary rocks, regionally metamorphosed during the Mesozoic to produce marbles and calc-silicate rocks, were contact metamorphosed at the end of the Cretaceous by the Lone Mountain granitic pluton. Mineral assemblages within the calc-silicates were in equilibrium with H[sub 2]O-rich fluids, while the marbles were in equilibrium with more CO[sub 2]-rich fluids. Mineralogical variation between two different calc-silicate lithologies is the result of differences in bulk rock chemical composition, which also results in differences in isotopic composition between the calc-silicate lithologies. delta O-18 and delta C-13 values show differences of greater than 6 and 4 per mil respectively across lithologic boundaries between interlayered calc-silicates and between interlayered marbles and calc-silicates. The absence of any systematic variation between delta O-18 and delta C-13 values in the calc-silicates suggests that isotopic variation due to decarbonation reactions was limited. The differences in mineralogy and isotopic composition indicate that permeability was enhanced by reaction, permitting the focused flow of fluid through the calc-silicates. Calculated mass balance variations in delta O-18 based on reaction space analysis and Rayleigh decarbonation cannot explain the observed variations of delta O-18, requiring infiltration of externally derived fluids, while the delta C-13 compositions in the calc-silicates can be explained by Rayleigh decarbonation alone.

Richards, I.J.; Labotka, T.C. (Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geochemical Sciences)

1992-01-01T23:59:59.000Z

76

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

77

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.

78

E-Print Network 3.0 - astatine isotopes Sample Search Results  

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

that includes a methane group (CH3) bonded to a halogen element (astatine, bromine... heavy water -- Water in which the molecules contain oxygen and deuterium, an isotope of...

79

Regional And Local Trends In Helium Isotopes, Basin And Range...  

Open Energy Info (EERE)

Range Province, Western North America- Evidence For Deep Permeable Pathways Abstract Fluids from the western margin of the Basin and Range have helium isotope ratios as high as...

80

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...

Note: This page contains sample records for the topic "oxygen isotope evidence" 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 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

82

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

Open Energy Info (EERE)

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

83

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

84

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

85

Climate change deduced from isotopes in tree rings  

SciTech Connect (OSTI)

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

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

1997-11-01T23:59:59.000Z

86

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.

87

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

88

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

89

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

90

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...

91

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

92

O isotopic composition of CaCO3 measured by continuous ow isotope ratio mass spectrometry  

E-Print Network [OSTI]

for the stable isotopes of carbon-13 and oxygen-18 to determine the ratios of the rare (usually the heavy The reaction of acid with calcite produces solid calcium hydrogen phosphate, liquid water, and two gases, water then are exposed to a dry- ice slush, and the carbon dioxide sublimates while the water stays frozen. After two

93

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

94

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

95

Carbon isotope ratios of organic compound fractions in oceanic suspended particles  

E-Print Network [OSTI]

Radiocarbon evidence of fossil-carbon cycling in sediments1968), Metabolic fractionation of carbon isotopes in marineof particulate organic carbon using bomb 14 C, Nature,

Hwang, Jeomshik; Druffel, Ellen R. M

2006-01-01T23:59:59.000Z

96

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...

97

EVIDENCE FOR CO DISSOCIATION ON RHODIUM SURFACES  

SciTech Connect (OSTI)

Carbon monoxide adsorbs molecularly on rhodium surfaces at 300K, but if the rhodium samples are heated in the presence of carbon monoxide, there is evidence for carbon-oxygen bond breaking at step and/or defect sites. The effects of step and defect site density, subsurface oxygen concentration, and oxygen dissolution into the rhodium lattice on CO dissociation are discussed.

Castner, D.G.; Dubois, L.H.; Sexton, B.A.; Somorjai, G.A.

1980-06-01T23:59:59.000Z

98

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

99

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

100

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

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

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

E-Print Network [OSTI]

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

Banner, Jay L.

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

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

104

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

105

Solid state oxygen sensor  

DOE Patents [OSTI]

Solid state oxygen sensors are provided with a yttria-doped zirconia as an electrolyte and use the electrochemical oxygen pumping of the zirconia electrolyte. A linear relationship between oxygen concentration and the voltage arising at a current plateau occurs when oxygen accessing the electrolyte is limited by a diffusion barrier. A diffusion barrier is formed herein with a mixed electronic and oxygen ion-conducting membrane of lanthanum-containing perovskite or zirconia-containing fluorite. A heater may be used to maintain an adequate oxygen diffusion coefficient in the mixed conducting layer.

Garzon, Fernando H. (Sante Fe, NM); Chung, Brandon W. (Los Alamos, NM); Raistrick, Ian D. (Los Alamos, NM); Brosha, Eric L. (Los Alamos, NM)

1996-01-01T23:59:59.000Z

106

On the maximum value of the cosmic abundance of oxygen and the oxygen yield  

E-Print Network [OSTI]

We search for the maximum oxygen abundance in spiral galaxies. Because this maximum value is expected to occur in the centers of the most luminous galaxies, we have constructed the luminosity - central metallicity diagram for spiral galaxies, based on a large compilation of existing data on oxygen abundances of HII regions in spiral galaxies. We found that this diagram shows a plateau at high luminosities (-22.3 oxygen abundance 12+log(O/H) ~ 8.87. This provides strong evidence that the oxygen abundance in the centers of the most luminous metal-rich galaxies reaches the maximum attainable value of oxygen abundance. Since some fraction of the oxygen (about 0.08 dex) is expected to be locked into dust grains, the maximum value of the true gas+dust oxygen abundance in spiral galaxies is 12+log(O/H) ~ 8.95. This value is a factor of ~ 2 higher than the recently estimated solar value. Based on the derived maximum oxygen abundance in galaxies, we found the oxygen yield to be about 0.0035, depending on the fraction of oxygen incorporated into dust grains.

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

2007-01-11T23:59:59.000Z

107

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

108

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

109

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...

110

Stable isotopes of authigenic minerals in variably-saturated fractured tuff  

SciTech Connect (OSTI)

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

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

1988-11-01T23:59:59.000Z

111

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

112

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

113

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

114

Oxygen partial pressure sensor  

DOE Patents [OSTI]

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

Dees, D.W.

1994-09-06T23:59:59.000Z

115

Geothermal reservoir temperatures estimated from the oxygen isotope...  

Open Energy Info (EERE)

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...

116

Geothermal Reservoir Temperatures Estimated from the Oxygen Isotope...  

Open Energy Info (EERE)

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...

117

Continuous surface ocean measurements of dissolved oxygen isotopes  

E-Print Network [OSTI]

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

Rafelski, Lauren Elmegreen

2012-01-01T23:59:59.000Z

118

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

Open Energy Info (EERE)

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

119

Oxygen isotope records of carboniferous seasonality on the Russian platform  

E-Print Network [OSTI]

in the prismatic secondary layers. Forty-one 8180 cycles are found in six profiles, with amplitudes ranging from 0.2%c to 2.7%c. The majority of cycles vary in amplitude from-0.4%0 to-1.2%0, with a mean of-0.8%o, representing annual temperature change of 2'C to 6'C...

Wang, Huayu

2012-06-07T23:59:59.000Z

120

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

Open Energy Info (EERE)

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...

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

Fractionation of Oxygen Isotopes in Phosphate during its Interactions with  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicyFeasibilityFieldMinds" Give Forms (AllKurt'sKinneeffectsIron

122

Geothermal reservoir temperatures estimated from the oxygen isotope  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to: navigation, searchGeaugaInformation Mexico - A Survey of Work

123

Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy ResourcesLoading map...(UtilityCounty,Orleans County, Vermont:OttawaCounty,2.8247524°,is a city inDrill

124

Geothermal Reservoir Temperatures Estimated from the Oxygen Isotope  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat Jump to: navigation, search OpenEIOpen EnergyRecoveryType

125

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

126

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

127

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

128

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...

129

Stable isotope enrichment  

ScienceCinema (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

2014-07-15T23:59:59.000Z

130

Integrated turbomachine oxygen plant  

SciTech Connect (OSTI)

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

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

2014-06-17T23:59:59.000Z

131

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

2005-07-12T23:59:59.000Z

132

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.

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

2004-11-23T23:59:59.000Z

133

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

134

Discovery of the Tungsten Isotopes  

E-Print Network [OSTI]

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

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

2009-03-25T23:59:59.000Z

135

Discovery of the Tin Isotopes  

E-Print Network [OSTI]

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

S. Amos; M. Thoennessen

2010-09-08T23:59:59.000Z

136

Discovery of the tungsten isotopes  

SciTech Connect (OSTI)

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

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

2010-05-15T23:59:59.000Z

137

Discovery of the Tungsten Isotopes  

E-Print Network [OSTI]

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

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

2009-01-01T23:59:59.000Z

138

Laser isotope separation  

DOE Patents [OSTI]

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

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

1988-01-01T23:59:59.000Z

139

Photochemical isotope separation  

DOE Patents [OSTI]

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

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

1987-01-01T23:59:59.000Z

140

Photochemical isotope separation  

DOE Patents [OSTI]

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

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

1987-04-28T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

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

E-Print Network [OSTI]

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

Ehleringer, Jim

142

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

143

Electron diffraction study of the sillenites Bi{sub 12}SiO{sub 20}, Bi{sub 25}FeO{sub 39} and Bi{sub 25}InO{sub 39}: Evidence of short-range ordering of oxygen-vacancies in the trivalent sillenites  

SciTech Connect (OSTI)

We present an electron diffraction study of three sillenites, Bi{sub 12}SiO{sub 20}, Bi{sub 25}FeO{sub 39}, and Bi{sub 25}InO{sub 39} synthesized using the solid-state method. We explore a hypothesis, inspired by optical studies in the literature, that suggests that trivalent sillenites have additional disorder not present in the tetravalent compounds. Electron diffraction patterns of Bi{sub 25}FeO{sub 39} and Bi{sub 25}InO{sub 39} show streaks that confirm deviations from the ideal sillenite structure. Multi-slice simulations of electron-diffraction patterns are presented for different perturbations to the sillenite structure - partial substitution of the M site by Bi{sup 3+}, random and ordered oxygen-vacancies, and a frozen-phonon model. Although comparison of experimental data to simulations cannot be conclusive, we consider the streaks as evidence of short-range ordered oxygen-vacancies.

Scurti, Craig A.; Arenas, D. J. [Department of Physics, University of North Florida, Jacksonville, FL 32224 (United States); Auvray, Nicolas [Department of Physics, University of North Florida, Jacksonville, FL 32224 (United States); Laboratoire de Nanotechnologie et d’Instrumentation Optique - UMR CNRS 6279, Université Technologie de Troyes, 12 rue Marie Curie, Troyes 10010 (France); Lufaso, Michael W. [Department of Chemistry, University of North Florida, Jacksonville, FL 32224 (United States); Takeda, Seiji [The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Kohno, Hideo [School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502 Japan (Japan)

2014-08-15T23:59:59.000Z

144

The Effect of Bicarbonate on Photosynthetic Oxygen Evolution in Flashing Light in Chloroplast Fragments  

E-Print Network [OSTI]

been resupplied. However, the final oxygen-evolving reac- tion after the accumulation of four positive of HCO3- in the Hill reaction indicates that this ion plays a critical role in the oxygen- evolving mechanism (1-3). Evidence is available that strongly suggests that HC03- acts on the oxygen-evolving side

Govindjee

145

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

146

High Selectivity Oxygen Delignification  

SciTech Connect (OSTI)

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

Lucian A. Lucia

2005-11-15T23:59:59.000Z

147

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

148

A Hydrogen Isotope of Mass 2 Before the publication of this definitive paper on the  

E-Print Network [OSTI]

. They probably estimated the chemical differences among isotopes to be small, perhaps too small to be measured, spectrographic evidence for the lines of 2 H obtained from samples of commercial tank hydro- gen. These lines

149

Transportation of medical isotopes  

SciTech Connect (OSTI)

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

Nielsen, D.L.

1997-11-19T23:59:59.000Z

150

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

151

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

152

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

SciTech Connect (OSTI)

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

Arndt Schimmelmann; Maria Mastalerz

2010-03-30T23:59:59.000Z

153

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

154

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

155

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

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

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

156

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

157

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

158

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

159

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

160

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

Note: This page contains sample records for the topic "oxygen isotope evidence" 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 METHODS IN HOMOGENEOUS CATALYSIS.  

SciTech Connect (OSTI)

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

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

2000-12-01T23:59:59.000Z

162

ARM - Measurement - Isotope ratio  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAciddropletgovMeasurementsIsotope ratio ARM

163

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. Ã? 2002 Elsevier Science B.V. All rights reserved. Keywords: sphaerosiderites; Cretaceous; oxygen

González, Luis A.

164

Laser isotope separation of erbium and other isotopes  

DOE Patents [OSTI]

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

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

1995-01-01T23:59:59.000Z

165

Water isotopes and the general circulation  

E-Print Network [OSTI]

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

Noone, David

166

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

167

Contiguous Platinum Monolayer Oxygen Reduction Electrocatalysts...  

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

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

168

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...

169

Home Monitoring of Oxygen Saturation and Symptoms for Sickle Cell Disease  

E-Print Network [OSTI]

Home Monitoring of Oxygen Saturation and Symptoms for Sickle Cell Disease Introduction and Aims There is evidence that the vaso-occlusive crises and other complications associated with sickle cell disease (SCD oxygen levels and the onset of sickle cell crises. A secondary objective of the study is to investigate

Oakley, Jeremy

170

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

171

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

172

High Selectivity Oxygen Delignification  

SciTech Connect (OSTI)

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

Arthur J. Ragauskas

2005-09-30T23:59:59.000Z

173

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

174

Lead and strontium isotopic evidence for crustal interaction and  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat JumpInc Place:Keystone CleanLaton, California:Laxenburg,Project Jump

175

Chromatographic hydrogen isotope separation  

DOE Patents [OSTI]

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

Aldridge, Frederick T. (Livermore, CA)

1981-01-01T23:59:59.000Z

176

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

SciTech Connect (OSTI)

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

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

1982-01-01T23:59:59.000Z

177

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

178

Oxygen-reducing catalyst layer  

DOE Patents [OSTI]

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

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

2011-03-22T23:59:59.000Z

179

Chemisorption and catalysis by metal clusters. II. Chemisorption of carbon monoxide and of oxygen by supported osmium clusters derived from Os/sub 3/(CO)/sub 12/ and from Os/sub 6/(CO)/sub 18/  

SciTech Connect (OSTI)

Carbon monoxide and oxygen have been chemisorbed at 293 K on the high-nuclearity carbonyl-protected clusters (the various species A) obtained by heating in vacuo to 523 K Os/sub 3/(CO)/sub 12/ or Os/sub 6/(CO)/sub 18/ impregnated on silica, alumina, or titania. The adsorption isotherms have a conventional appearance, but most are composed of a primary and a secondary region. Material adsorbed in the secondary region is removed by evacuation at room temperature whereas that adsorbed in the primary region is removed by evacuation at elevated temperatures. For species A/alumina and the species A/titania the primary region is complete and the secondary region commences when the pressure over the adsorbent is 0.2 Torr. Species A/silica gave no secondary region in oxygen adsorption. Adsorption and subsequent temperature-programmed desorption of (/sup 18/O)CO occurred without any dilution by (/sup 16/O)CO, indicating that ligand-(/sup 16/O)CO and adsorbed-(/sup 18/O)CO do not exchange even at elevated temperatures. The two species A/aluminas catalyzed oxygen isotope exchange at 293 K. From the experimental evidence it is deduced that carbon monoxide and oxygen each adsorbs molecularly in both the primary and the secondary regions. In the primary region carbon monoxide adsorption occurs at osmium sites on the cluster framework, whereas in the secondary region it occurs at ligand-carbon bonded to osmium. For oxygen, adsorption in the primary region is again at osmium sites on the cluster framework but that in the secondary region is at osmium sites of the cluster framework suitably modified as a result of the support-cluster interaction.

Hunt, D.J.; Jackson, S.D.; Moyes, R.B.; Wells, P.B.; Whyman, R.

1984-04-01T23:59:59.000Z

180

Isotopic Trends in Production of Superheavies  

SciTech Connect (OSTI)

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

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

2005-11-21T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

The marine biogeochemistry of zinc isotopes  

E-Print Network [OSTI]

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

John, Seth G

2007-01-01T23:59:59.000Z

182

Electrochemical studies of quinone oxygen  

SciTech Connect (OSTI)

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

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

1990-02-01T23:59:59.000Z

183

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

184

Isotope separation by laser means  

DOE Patents [OSTI]

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

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

1982-06-15T23:59:59.000Z

185

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

186

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

187

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

SciTech Connect (OSTI)

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

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

1980-05-01T23:59:59.000Z

188

Mixed oxygen ion/electron-conducting ceramics for oxygen separation  

SciTech Connect (OSTI)

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

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

1995-05-01T23:59:59.000Z

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 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

190

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

191

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.

192

Method for laser induced isotope enrichment  

DOE Patents [OSTI]

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

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

2004-09-07T23:59:59.000Z

193

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

194

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

E-Print Network [OSTI]

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

Mcdonough, William F.

195

Compelling Research Opportunities using Isotopes  

SciTech Connect (OSTI)

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

None

2009-04-23T23:59:59.000Z

196

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

197

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

198

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

199

Physics with isotopically controlled semiconductors  

SciTech Connect (OSTI)

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

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

2010-07-15T23:59:59.000Z

200

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

Note: This page contains sample records for the topic "oxygen isotope evidence" 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.


201

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

202

Evolution of Photosynthesis and Biospheric Oxygenation Contingent Upon Nitrogen Fixation?  

E-Print Network [OSTI]

How photosynthesis by Precambrian cyanobacteria oxygenated Earth's biosphere remains incompletely understood. Here it is argued that the oxic transition, which took place between approximately 2.3 and 0.5 Gyr ago, required a great proliferation of cyanobacteria, and this in turn depended on their ability to fix nitrogen via the nitrogenase enzyme system. However, the ability to fix nitrogen was not a panacea, and the rate of biospheric oxygenation may still have been affected by nitrogen constraints on cyanobacterial expansion. Evidence is presented for why cyanobacteria probably have a great need for fixed nitrogen than other prokaryotes, underscoring the importance of their ability to fix nitrogen. The connection between nitrogen fixation and the evolution of photosynthesis is demonstrated by the similarities between nitrogenase and enzymes critical for the biosynthesis of (bacterio)chlorophyll. It is hypothesized that biospheric oxygenation would not have occurred if the emergence of cyanobacteria had not ...

Grula, J W

2006-01-01T23:59:59.000Z

203

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

204

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

E-Print Network [OSTI]

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

205

Modulation of mixed-phase titania photoluminescence by oxygen adsorption  

SciTech Connect (OSTI)

We investigate the effect of oxygen (O{sub 2}) adsorption on photoluminescence properties of mixed-phase titania nanoparticle films deposited by femtosecond pulsed laser deposition, aiming to assess preliminary conclusions about the feasibility of opto-chemical sensing based on titania. We evidence that O{sub 2} produces opposite responses in rutile and anatase photoluminescence efficiency, highlighting interesting potentialities for future double-parametric optical sensing based on titania. The results evidence an important role of lattice oxygen atoms, suggesting that the standard Schottky barrier mechanism driving the response toward gas species in most used metal-oxide sensors (e.g., tin dioxide) is not the only active mechanism in titania.

Pallotti, D.; Orabona, E.; Amoruso, S.; Maddalena, P. [Dipartimento di Fisica, Universitá degli Studi di Napoli “Federico II,” Via Cintia, I-80126 Napoli (Italy); Institute for Superconductors, Oxides and Innovative Materials and Devices, CNR-SPIN, U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy); Lettieri, S., E-mail: stefano.lettieri@spin.cnr.it [Institute for Superconductors, Oxides and Innovative Materials and Devices, CNR-SPIN, U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy)

2014-07-21T23:59:59.000Z

206

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...

207

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

208

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...

209

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

210

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...

211

Oxygen Concentration Microgradients for Cell Culture  

E-Print Network [OSTI]

for technology that can control microscale oxygen gradientstechnology is the ability to rapidly generate and alter oxygentechnology should enable numerous studies in the field of biology where oxygen

Park, Jaehyun

2010-01-01T23:59:59.000Z

212

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

213

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...

214

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

215

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

216

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

217

Identification and lattice location of oxygen impurities in -Si3N4 J. C. Idrobo,1,2,3,a  

E-Print Network [OSTI]

Identification and lattice location of oxygen impurities in -Si3N4 J. C. Idrobo,1,2,3,a M. P. Oxley but there is no direct evidence for their identity or lattice location. In bulk materials electron microscopy can of oxygen in the bulk material. Scanning transmission electron microscopy S/TEM has the spatial resolution

Pennycook, Steve

218

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.

219

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

E-Print Network [OSTI]

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

Ehleringer, Jim

220

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

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

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

222

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.

223

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

DOE Patents [OSTI]

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

Schultz, Hyman (Jefferson Boro, PA)

1992-01-01T23:59:59.000Z

224

Oxygen uptake of benthic systems  

E-Print Network [OSTI]

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

Priebe, William Franklin

1972-01-01T23:59:59.000Z

225

Isotope Cancer Treatment Research at LANL  

ScienceCinema (OSTI)

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

Weidner, John; Nortier, Meiring

2014-06-02T23:59:59.000Z

226

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

SciTech Connect (OSTI)

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

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

2013-11-13T23:59:59.000Z

227

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

228

Atomic oxygen patterning from a biomedical needle-plasma source  

SciTech Connect (OSTI)

A “plasma needle” is a cold plasma source operating at atmospheric pressure. Such sources interact strongly with living cells, but experimental studies on bacterial samples show that this interaction has a surprising pattern resulting in circular or annular killing structures. This paper presents numerical simulations showing that this pattern occurs because biologically active reactive oxygen and nitrogen species are produced dominantly where effluent from the plasma needle interacts with ambient air. A novel solution strategy is utilised coupling plasma produced neutral (uncharged) reactive species to the gas dynamics solving for steady state profiles at the treated biological surface. Numerical results are compared with experimental reports corroborating evidence for atomic oxygen as a key bactericidal species. Surface losses are considered for interaction of plasma produced reactants with reactive solid and liquid interfaces. Atomic oxygen surface reactions on a reactive solid surface with adsorption probabilities above 0.1 are shown to be limited by the flux of atomic oxygen from the plasma. Interaction of the source with an aqueous surface showed hydrogen peroxide as the dominant species at this interface.

Kelly, Seán; Turner, Miles M. [School of Physical Science and National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland)] [School of Physical Science and National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland)

2013-09-28T23:59:59.000Z

229

Isotope specific resolution recovery image reconstruction in high resolution PET imaging  

SciTech Connect (OSTI)

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution recovery image reconstruction. The benefits are expected to be more substantial for more energetic positron emitting isotopes such as Oxygen-15 and Rubidium-82.

Kotasidis, Fotis A. [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom)] [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom); Angelis, Georgios I. [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia)] [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia); Anton-Rodriguez, Jose; Matthews, Julian C. [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom)] [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom); Reader, Andrew J. [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom)] [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland) [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland); Geneva Neuroscience Centre, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30 001, Groningen 9700 RB (Netherlands)

2014-05-15T23:59:59.000Z

230

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

231

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

232

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

233

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.

234

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

235

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

236

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

237

AN ELECTRICAL OXYGEN-TEMPERATURE METER  

E-Print Network [OSTI]

426 AN ELECTRICAL OXYGEN-TEMPERATURE METER FOR FISHERY BIOLOGISTS SEP 2 1196: vuUiJo HIM. . SPECIAL and Wildlife, Daniel H. Janzen, Director AN ELECTRICAL OXYGEN-TEMPERATURE METER FOR FISHERY BIOLOGISTS -temperature meter 11 Maintenance and trouble -shooting 12 #12;AN ELECTRICAL OXYGEN-TEMPERATURE METER

238

Effects of oxygen on fracturing fluids  

SciTech Connect (OSTI)

The stability of polysaccharide gels at high temperature is limited by such factors as pH, mechanical degradation, and oxidants. Oxygen is unavoidably placed in fracturing fluids through dissolution of air. To prevent premature degradation of the fracturing fluid by this oxidant, oxygen scavengers are commonly used. In this paper, the effects of oxygen and various oxygen scavengers on gel stability will be presented. Mechanical removal of oxygen resulted in surprisingly stable fracturing gels at 275 F. However, chemical removal of oxygen gave mixed results. Test data from sodium thiosulfate, sodium sulfite, and sodium erythorbate used as oxygen scavengers/gel stabilizers showed that the efficiency of oxygen removal from gels did not directly coincide with the viscosity retention of the gel, and large excesses of additives were necessary to provide optimum gel stabilization. The inability of some oxygen scavengers to stabilize the gel was the result of products created from the interaction of oxygen with the oxygen scavenger, which in turn, produced species that degraded the gel. The ideal oxygen scavenger should provide superior gel stabilization without creating detrimental side reaction products. Of the materials tested, sodium thiosulfate appeared to be the most beneficial.

Walker, M.L.; Shuchart, C.E.; Yaritz, J.G.; Norman, L.R.

1995-11-01T23:59:59.000Z

239

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.

240

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

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

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

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

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

242

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

243

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 indium–gallium–zinc 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

244

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

245

Analysis of hydrogen isotope mixtures  

DOE Patents [OSTI]

An apparatus and method for determining the concentrations of hydrogen isotopes in a sample. Hydrogen in the sample is separated from other elements using a filter selectively permeable to hydrogen. Then the hydrogen is condensed onto a cold finger or cryopump. The cold finger is rotated as pulsed laser energy vaporizes a portion of the condensed hydrogen, forming a packet of molecular hydrogen. The desorbed hydrogen is ionized and admitted into a mass spectrometer for analysis.

Villa-Aleman, Eliel (Aiken, SC)

1994-01-01T23:59:59.000Z

246

Lycopene cyclase paralog CruP protects against reactive oxygen species in oxygenic  

E-Print Network [OSTI]

, quenching singlet oxygen generated during the water-splitting process of photo- synthesis (10, 11). VariousLycopene cyclase paralog CruP protects against reactive oxygen species in oxygenic photosynthetic cyclase. Instead, we show that CruP aids in preventing accumulation of reactive oxygen species (ROS

Wurtzel, Eleanore

247

Experimental Effects of Atomic Oxygen on the Development of an Electric Discharge Oxygen Iodine Laser  

E-Print Network [OSTI]

state I. Conventionally, a two-phase (gas-liquid) chemistry singlet oxygen generator (SOG) producesExperimental Effects of Atomic Oxygen on the Development of an Electric Discharge Oxygen Iodine of the electric discharge iodine laser continues, the role of oxygen atoms downstream of the discharge region

Carroll, David L.

248

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

249

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

250

IS THE SUN LIGHTER THAN THE EARTH? ISOTOPIC CO IN THE PHOTOSPHERE, VIEWED THROUGH THE LENS OF THREE-DIMENSIONAL SPECTRUM SYNTHESIS  

SciTech Connect (OSTI)

We consider the formation of solar infrared (2-6 {mu}m) rovibrational bands of carbon monoxide (CO) in CO5BOLD 3D convection models, with the aim of refining abundances of the heavy isotopes of carbon ({sup 13}C) and oxygen ({sup 18}O, {sup 17}O), to compare with direct capture measurements of solar wind light ions by the Genesis Discovery Mission. We find that previous, mainly 1D, analyses were systematically biased toward lower isotopic ratios (e.g., R {sub 23} {identical_to} {sup 12}C/{sup 13}C), suggesting an isotopically 'heavy' Sun contrary to accepted fractionation processes that were thought to have operated in the primitive solar nebula. The new 3D ratios for {sup 13}C and {sup 18}O are R {sub 23} = 91.4 {+-} 1.3 (R {sub Circled-Plus} = 89.2) and R {sub 68} = 511 {+-} 10 (R {sub Circled-Plus} = 499), where the uncertainties are 1{sigma} and 'optimistic'. We also obtained R {sub 67} = 2738 {+-} 118 (R {sub Circled-Plus} = 2632), but we caution that the observed {sup 12}C{sup 17}O features are extremely weak. The new solar ratios for the oxygen isotopes fall between the terrestrial values and those reported by Genesis (R {sub 68} = 530, R {sub 67} = 2798), although including both within 2{sigma} error flags, and go in the direction favoring recent theories for the oxygen isotope composition of Ca-Al inclusions in primitive meteorites. While not a major focus of this work, we derive an oxygen abundance, {epsilon}{sub O} {approx} 603 {+-} 9 ppm (relative to hydrogen; log {epsilon} {approx} 8.78 on the H = 12 scale). The fact that the Sun is likely lighter than the Earth, isotopically speaking, removes the necessity of invoking exotic fractionation processes during the early construction of the inner solar system.

Ayres, Thomas R. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States)] [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Lyons, J. R. [Department of Earth and Space Sciences, University of California, Los Angeles, CA (United States)] [Department of Earth and Space Sciences, University of California, Los Angeles, CA (United States); Ludwig, H.-G.; Caffau, E. [Zentrum fuer Astronomie der Universitaet Heidelberg, Heidelberg (Germany)] [Zentrum fuer Astronomie der Universitaet Heidelberg, Heidelberg (Germany); Wedemeyer-Boehm, S., E-mail: Thomas.Ayres@Colorado.edu [Institute of Theoretical Astrophysics, University of Oslo, Oslo (Norway)

2013-03-01T23:59:59.000Z

251

Atom trap trace analysis of krypton isotopes  

SciTech Connect (OSTI)

A new method of ultrasensitive isotope trace analysis has been developed. This method, based on the technique of laser manipulation of neutral atoms, has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton gas sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. This method is free of contamination from other isotopes and elements and can be applied to several different isotope tracers for a wide range of applications. The demonstrated detection efficiency is 1 x 10{sup {minus}7}. System improvements could increase the efficiency by many orders of magnitude.

Bailey, K.; Chen, C. Y.; Du, X.; Li, Y. M.; Lu, Z.-T.; O'Connor, T. P.; Young, L.

1999-11-17T23:59:59.000Z

252

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...

253

Stable Isotope Protocols: Sampling and Sample Processing  

E-Print Network [OSTI]

plants, benthic microalgae [BMI], benthic macroalgae) andin a dessicator, prior to analysis. A.2 Benthic microalgaeBenthic microalgae (BMI) can be collected for isotope

Levin, Lisa A; Currin, Carolyn

2012-01-01T23:59:59.000Z

254

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...

255

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

E-Print Network [OSTI]

of quartz cement Ann M.E. Marchanda,*, Calum I. Macaulayb , R. Stuart Haszeldinea , Anthony E. Fallickc--direct measurements were not possible) precipitated in the sandstones at temperatures jC; (2) the second zone B in the sandstones most likely between 70 and 90 jC; (3) the third zone C (homogeneous CL pattern and directly

Haszeldine, Stuart

256

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

E-Print Network [OSTI]

feedstock is processed into Syngas (mixture of CO and H2)called synthetic gas or syngas) reacts with catalysts (feedstock is processed into Syngas (mixture of CO and H2)

Chan, Sharleen

257

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

E-Print Network [OSTI]

in this area would be revolutionary, reducing toxic gas emissions6 and the devastation of natural environments7 relative to natural abundance H2O under single and multi-turnover conditions. The findings reported here while bolstering the global economy.8 A major objective in the basic energy sciences is to improve

Roth, Justine P.

258

CARBON AND OXYGEN ISOTOPIC ANALYSIS: BUG, CHEROKEE, AND PATTERSON CANYON FIELDS, SAN JUAN COUNTY, UTAH  

SciTech Connect (OSTI)

Over 400 million barrels (64 million m{sup 3}) of oil have been produced from the shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation in the Paradox Basin, Utah and Colorado. With the exception of the giant Greater Aneth field, the other 100 plus oil fields in the basin typically contain 2 to 10 million barrels (0.3-1.6 million m{sup 3}) of original oil in place. Most of these fields are characterized by high initial production rates followed by a very short productive life (primary), and hence premature abandonment. Only 15 to 25 percent of the original oil in place is recoverable during primary production from conventional vertical wells. An extensive and successful horizontal drilling program has been conducted in the giant Greater Aneth field. However, to date, only two horizontal wells have been drilled in small Ismay and Desert Creek fields. The results from these wells were disappointing due to poor understanding of the carbonate facies and diagenetic fabrics that create reservoir heterogeneity. These small fields, and similar fields in the basin, are at high risk of premature abandonment. At least 200 million barrels (31.8 million m{sup 3}) of oil will be left behind in these small fields because current development practices leave compartments of the heterogeneous reservoirs undrained. Through proper geological evaluation of the reservoirs, production may be increased by 20 to 50 percent through the drilling of low-cost single or multilateral horizontal legs from existing vertical development wells. In addition, horizontal drilling from existing wells minimizes surface disturbances and costs for field development, particularly in the environmentally sensitive areas of southeastern Utah and southwestern Colorado.

David E. Eby; Thomas C. Chidsey Jr; Kevin McClure; Craig D. Morgan; Stephen T. Nelson

2003-12-01T23:59:59.000Z

259

Growth rates, stable oxygen isotopes (d18 O), and strontium (Sr/Ca)  

E-Print Network [OSTI]

Mg calcite, 21 mol% Mg) from Palau, four A. wellsi (highMg calcite, 21 mol% Mg) from Saipan, and three specimen from Palau spanning 1945­2001.5. In Saipan, speciesspecific and mineralogical effects appear. On multidecadal timescales, A. wellsi sclerosponge d18 O in Palau tracked the Southern Oscillation Index

Adkins, Jess F.

260

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

E-Print Network [OSTI]

UEET characterized engine/ combustor emissions focusing onof alternative fuels and new combustor technology while

Chan, Sharleen

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

The effect of phosphomonoesterases on the oxygen isotope composition of phosphate  

E-Print Network [OSTI]

a a Institute of Agricultural Sciences, ETH Zurich, Eschikon 33, CH-8315 Lindau, Switzerland b Laboratory of Organic Chemistry, ETH Zurich, ETH Ho¨nggerberg, CH-8093 Zurich, Switzerland c Geological Institute, ETH Zurich, Sonneggstrasse 5, CH-8092 Zurich, Switzerland Received 2 May 2013; accepted in revised form 6

Gilli, Adrian

262

Isotopic dependence of predissociation linewidths in the Schumann-Runge bands of oxygen  

E-Print Network [OSTI]

Cheung,A.S.-C. Mok,D.K.-W. Yoshino,K. Parkinson,W.H. Jamieson,M.J. Dalgarno,A. Child,M.S. Journal of Chemical Physics, Vol. 103 pp 2369-2371

Cheung, A.S.-C.; Mok, D.K.-W.; Yoshino, K.; Parkinson, W.H.; Jamieson, M.J.

263

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

264

An Oxygen Isotope Study Of Hydrothermal Alteration In The Lake City  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of InspectorConcentrating SolarElectricEnergyCT Biomass Facility Jump to:Operations at the Coso Geothermal

265

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

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160 East 300Algoil JumpAltergyExperiments | Open Energy InformationWaterItaly | Open

266

15N2 formation and fast oxygen isotope exchange during pulsed 15N18O  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies | BlandinePrincetonOPT OpticsFrequently Asked12

267

A simplified method for obtaining high-purity perchlorate from groundwater for isotope analyses.  

SciTech Connect (OSTI)

Investigations into the occurrence and origin of perchlorate (ClO{sub 4}{sup -}) found in groundwater from across North America have been sparse until recent years, and there is mounting evidence that natural formation mechanisms are important. New opportunities for identifying groundwater perchlorate and its origin have arisen with the utilization of improved detection methods and sampling techniques. Additionally, application of the forensic potential of isotopic measurements has begun to elucidate sources, potential formation mechanisms and natural attenuation processes. Procedures developed appear to be amenable to enable high precision stable isotopic analyses, as well as lower precision AMS analyses of {sup 36}Cl. Immediate work is in analyzing perchlorate isotope standards and developing full analytical accuracy and uncertainty expectations. Field samples have also been collected, and will be analyzed when final qa/qc samples are deemed acceptable.

vonKiparski, G; Hillegonds, D

2011-04-04T23:59:59.000Z

268

OXYGEN 18 EXCHANGE REACTIONS OF ALDEHYDES AND KETONES  

E-Print Network [OSTI]

OXYGEN 18 EXCHANGE REACTIONS OF ALDEHYDES AND KETONES TWO-eng-48 OXYGEN 18 EXCHANGE REACTIONS OF ALDEHYDES AND KETONES

Byrn, Marianne; Calvin, Melvin

1965-01-01T23:59:59.000Z

269

Gamma Spectrum from Neutron Capture on Tungsten Isotopes  

E-Print Network [OSTI]

FROM NEUTRON CAPTURE ON TUNGSTEN ISOTOPES A. M. HURST ?1,2 ,capture on the stable tungsten isotopes is presented, withknown decay schemes of the tungsten isotopes from neutron

Hurst, Aaron

2011-01-01T23:59:59.000Z

270

Spatial periphery of lithium isotopes  

SciTech Connect (OSTI)

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

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

2013-12-15T23:59:59.000Z

271

Evolution of Photosynthesis and Biospheric Oxygenation Contingent Upon Nitrogen Fixation?  

E-Print Network [OSTI]

How photosynthesis by Precambrian cyanobacteria oxygenated Earth's biosphere remains incompletely understood. Here it is argued that the oxic transition, which took place between approximately 2.3 and 0.5 Gyr ago, required a great proliferation of cyanobacteria, and this in turn depended on their ability to fix nitrogen via the nitrogenase enzyme system. However, the ability to fix nitrogen was not a panacea, and the rate of biospheric oxygenation may still have been affected by nitrogen constraints on cyanobacterial expansion. Evidence is presented for why cyanobacteria probably have a great need for fixed nitrogen than other prokaryotes, underscoring the importance of their ability to fix nitrogen. The connection between nitrogen fixation and the evolution of photosynthesis is demonstrated by the similarities between nitrogenase and enzymes critical for the biosynthesis of (bacterio)chlorophyll. It is hypothesized that biospheric oxygenation would not have occurred if the emergence of cyanobacteria had not been preceded by the evolution of nitrogen fixation, and if these organisms had not also acquired the ability to fix nitrogen at the beginning of or very early in their history. The evolution of nitrogen fixation also appears to have been a precondition for the evolution of (bacterio)chlorophyll-based photosynthesis. Given that some form of chlorophyll is obligatory for true photosynthesis, and its light absorption and chemical properties make it a "universal pigment," it may be predicted that the evolution of nitrogen fixation and photosynthesis are also closely linked on other Earth- like planets.

John W. Grula

2006-05-12T23:59:59.000Z

272

Evidence for serpentinite fluid in convergent margin systems: The example of El Salvador (Central America) arc lavas  

E-Print Network [OSTI]

Evidence for serpentinite fluid in convergent margin systems: The example of El Salvador (Central isotopes, has been carried out on El Salvador subduction-related lavas. The rocks have arc), Evidence for serpentinite fluid in convergent margin systems: The example of El Salvador (Central America

Doglioni, Carlo

273

THE GENESIS SOLAR WIND CONCENTRATOR TARGET: MASS FRACTIONATION CHARACTERISED BY NE ISOTOPES  

SciTech Connect (OSTI)

The concentrator on Genesis provides samples of increased fluences of solar wind ions for precise determination of the oxygen isotopic composition of the solar wind. The concentration process caused mass fractionation as function of the radial target position. They measured the fractionation using Ne released by UV laser ablation along two arms of the gold cross from the concentrator target to compare measured Ne with modeled Ne. The latter is based on simulations using actual conditions of the solar wind during Genesis operation. Measured Ne abundances and isotopic composition of both arms agree within uncertainties indicating a radial symmetric concentration process. Ne data reveal a maximum concentration factor of {approx} 30% at the target center and a target-wide fractionation of Ne isotopes of 3.8%/amu with monotonously decreasing {sup 20}Ne/{sup 22}Ne ratios towards the center. The experimentally determined data, in particular the isotopic fractionation, differ from the modeled data. They discuss potential reasons and propose future attempts to overcome these disagreements.

WIENS, ROGER C. [Los Alamos National Laboratory; OLINGER, C. [Los Alamos National Laboratory; HEBER, V.S. [Los Alamos National Laboratory; REISENFELD, D.B. [Los Alamos National Laboratory; BURNETT, D.S. [Los Alamos National Laboratory; ALLTON, J.H. [Los Alamos National Laboratory; BAUR, H. [Los Alamos National Laboratory; WIECHERT, U. [Los Alamos National Laboratory; WIELER, R. [Los Alamos National Laboratory

2007-01-02T23:59:59.000Z

274

Isotopic Analysis- Fluid At Dixie Valley Geothermal Area (Kennedy...  

Open Energy Info (EERE)

permeable fluid flow pathways and the helium Isotopic composition of the surface fluids. The authors suggest that helium isotopes are the best and possibly the only...

275

CRAD, Engineering - Oak Ridge National Laboratory High Flux Isotope...  

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

Oak Ridge National Laboratory High Flux Isotope Reactor CRAD, Engineering - Oak Ridge National Laboratory High Flux Isotope Reactor February 2007 A section of Appendix C to DOE G...

276

CRAD, Maintenance - Oak Ridge National Laboratory High Flux Isotope...  

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

Maintenance - Oak Ridge National Laboratory High Flux Isotope Reactor CRAD, Maintenance - Oak Ridge National Laboratory High Flux Isotope Reactor February 2007 A section of...

277

CRAD, Engineering - Oak Ridge National Laboratory High Flux Isotope...  

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

Engineering - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR CRAD, Engineering - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR...

278

CRAD, Maintenance - Oak Ridge National Laboratory High Flux Isotope...  

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

Maintenance - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR CRAD, Maintenance - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR...

279

CRAD, Management- Oak Ridge National Laboratory High Flux Isotope...  

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

Management- Oak Ridge National Laboratory High Flux Isotope Reactor CRAD, Management- Oak Ridge National Laboratory High Flux Isotope Reactor February 2007 A section of Appendix C...

280

Enriched Stable Isotope Materials and Chemistry | ornl.gov  

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

Enriched Stable Isotope Materials and Chemistry SHARE Enriched Stable Isotope Materials and Chemistry Reductiondistillation of calcium-48 metal valued at over 900,000. An...

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

applied isotope techniques: Topics by E-print Network  

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

M. 22 Applied Radiation and Isotopes 55 (2001) 707713 Bronchial dosimeter for radon progeny Biology and Medicine Websites Summary: Applied Radiation and Isotopes 55 (2001)...

282

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

2012-01-17T23:59:59.000Z

283

Positive and inverse isotope effect on superconductivity  

E-Print Network [OSTI]

This article improves the BCS theory to include the inverse isotope effect on superconductivity. An affective model can be deduced from the model including electron-phonon interactions, and the phonon-induced attraction is simply and clearly explained on the electron Green function. The focus of this work is on how the positive or inverse isotope effect occurs in superconductors.

Tian De Cao

2009-09-04T23:59:59.000Z

284

Advanced Mass Spectrometers for Hydrogen Isotope Analyses  

SciTech Connect (OSTI)

This report is a summary of the results of a joint Savannah River Laboratory (SRL) - Savannah River Plant (SRP) ''Hydrogen Isotope Mass Spectrometer Evaluation Program''. The program was undertaken to evaluate two prototype hydrogen isotope mass spectrometers and obtain sufficient data to permit SRP personnel to specify the mass spectrometers to replace obsolete instruments.

Chastagner, P.

2001-08-01T23:59:59.000Z

285

Isotopes  

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

are saving lives, advancing cutting-edge research and keeping the U.S. safe. Strontium-82 produced at Los Alamos is used in hospitals nation- and world-wide for critical...

286

ISOTOPES  

E-Print Network [OSTI]

1955). Production of Heavy water, 37. G.M. Keyser, D.B.Economy of Production of Heavy Water, Turin, Italy (1970),world production of heavy water to ~1ay, 1977. From data

Lederer, C. Michael

2013-01-01T23:59:59.000Z

287

ISOTOPES  

E-Print Network [OSTI]

constructed to enrich liquid UF6 slightly as feed for thej) b. Optimum a. s: .X. UF6 feed, (kg per year) XBL 7912 -

Lederer, C. Michael

2013-01-01T23:59:59.000Z

288

Isotopes  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFunInfrared LandResponsesIon/SurfacePump-Testing Sign

289

ISOTOPES  

E-Print Network [OSTI]

5-7. 1975, British Nuclear Engineering Society (1975). 87.London, March British Nuclear Engineering Society (1975).T.H. Pigford, Nuclear Chemical Engineering (1St edition),

Lederer, C. Michael

2013-01-01T23:59:59.000Z

290

Myocardial Reloading after Extracorporeal Membrane Oxygenation...  

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

Protein Synthesis. Abstract: Extracorporeal membrane oxygenation (ECMO) unloads the heart providing a bridge to recovery in children after myocardial stunning. Mortality after...

291

Oxygen Concentration Microgradients for Cell Culture.  

E-Print Network [OSTI]

??There is a growing need for technology that can control microscale oxygen gradients onto a tissue or culture sample in vitro. This dissertation introduces the… (more)

Park, Jaehyun

2010-01-01T23:59:59.000Z

292

Oxygen ion-beam microlithography  

DOE Patents [OSTI]

A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used.

Tsuo, Y. Simon (Lakewood, CO)

1991-01-01T23:59:59.000Z

293

Recovery Act: Novel Oxygen Carriers for Coal-fueled Chemical Looping  

SciTech Connect (OSTI)

Chemical Looping Combustion (CLC) could totally negate the necessity of pure oxygen by using oxygen carriers for purification of CO{sub 2} stream during combustion. It splits the single fuel combustion reaction into two linked reactions using oxygen carriers. The two linked reactions are the oxidation of oxygen carriers in the air reactor using air, and the reduction of oxygen carriers in the fuel reactor using fuels (i.e. coal). Generally metal/metal oxides are used as oxygen carriers and operated in a cyclic mode. Chemical looping combustion significantly improves the energy conversion efficiency, in terms of the electricity generation, because it improves the reversibility of the fuel combustion process through two linked parallel processes, compared to the conventional combustion process, which is operated far away from its thermo-equilibrium. Under the current carbon-constraint environment, it has been a promising carbon capture technology in terms of fuel combustion for power generation. Its disadvantage is that it is less mature in terms of technological commercialization. In this DOE-funded project, accomplishment is made by developing a series of advanced copper-based oxygen carriers, with properties of the higher oxygen-transfer capability, a favorable thermodynamics to generate high purity of CO{sub 2}, the higher reactivity, the attrition-resistance, the thermal stability in red-ox cycles and the achievement of the auto-thermal heat balance. This will be achieved into three phases in three consecutive years. The selected oxygen carriers with final-determined formula were tested in a scaled-up 10kW coal-fueled chemical looping combustion facility. This scaled-up evaluation tests (2-day, 8-hour per day) indicated that, there was no tendency of agglomeration of copper-based oxygen carriers. Only trace-amount of coke or carbon deposits on the copper-based oxygen carriers in the fuel reactor. There was also no evidence to show the sulphidization of oxygen carriers in the system by using the high-sulfur-laden asphalt fuels. In all, the scaled-up test in 10 kW CLC facility demonstrated that the preparation method of copper-based oxygen carrier not only help to maintain its good reactivity, also largely minimize its agglomeration tendency.

Pan, Wei-Ping; Cao, Yan

2012-11-30T23:59:59.000Z

294

Atomic vapor laser isotope separation of lead-210 isotope  

DOE Patents [OSTI]

An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207.

Scheibner, Karl F. (Tracy, CA); Haynam, Christopher A. (Pleasanton, CA); Johnson, Michael A. (Pleasanton, CA); Worden, Earl F. (Diablo, CA)

1999-01-01T23:59:59.000Z

295

Atomic vapor laser isotope separation of lead-210 isotope  

DOE Patents [OSTI]

An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207. 5 figs.

Scheibner, K.F.; Haynam, C.A.; Johnson, M.A.; Worden, E.F.

1999-08-31T23:59:59.000Z

296

Transient oxygen consumption rate measurements with the BDT?M? oxygen biosensor system  

E-Print Network [OSTI]

Oxygen consumption rate (OCR) is a reliable indicator of tissue health. Recently, the OCR of isolated human islets has been shown to predict transplant outcome in diabetic mice. The Oxygen Biosensor System (OBS) is a ...

Low, Clarke Alan

2008-01-01T23:59:59.000Z

297

IMPACT OF OXYGENATED FUEL ON DIESEL ENGINE PERFORMANCE AND EMISSIONS  

SciTech Connect (OSTI)

As evidenced by recent lawsuits brought against operators of large diesel truck fleets [1] and by the Consent Decree brought against the heavy-duty diesel manufacturers [2], the environmental and health effects of diesel engine emissions continue to be a significant concern. Reduction of diesel engine emissions has traditionally been achieved through a combination of fuel system, combustion chamber, and engine control modifications [3]. Catalytic aftertreatment has become common on modern diesel vehicles, with the predominant device being the diesel oxidation catalytic converter [3]. To enable advanced after-treatment devices and to directly reduce emissions, significant recent interest has focused on reformulation of diesel fuel, particularly the reduction of sulfur content. The EPA has man-dated that diesel fuel will have only 15 ppm sulfur content by 2007, with current diesel specifications requiring around 300 ppm [4]. Reduction of sulfur will permit sulfur-sensitive aftertreatment devices, continuously regenerating particulate traps, NOx control catalysts, and plasma assisted catalysts to be implemented on diesel vehicles [4]. Another method of reformulating diesel fuel to reduce emissions is to incorporate oxygen in the fuel, as was done in the reformulation of gasoline. The use of methyl tertiary butyl ether (MTBE) in reformulated gasoline has resulted in contamination of water resources across the country [5]. Nonetheless, by relying on the lessons learned from MTBE, oxygenation of diesel fuel may be accomplished without compromising water quality. Oxygenation of diesel fuel offers the possibility of reducing particulate matter emissions significantly, even for the current fleet of diesel vehicles. The mechanism by which oxygen content leads to particulate matter reductions is still under debate, but recent evidence shows clearly that ''smokeless'' engine operation is possible when the oxygen content of diesel fuel reaches roughly 38% by weight [6]. The potential improvements in energy efficiency within the transportation section, particularly in sport utility vehicles and light-duty trucks, that can be provided by deployment of diesel engines in passenger cars and trucks is a strong incentive to develop cleaner burning diesel engines and cleaner burning fuels for diesel engines. Thus, serious consideration of oxygenated diesel fuels is of significant practical interest and value to society. In the present work, a diesel fuel reformulating agent, CETANERTM, has been examined in a popular light-medium duty turbodiesel engine over a range of blending ratios. This additive is a mixture of glycol ethers and can be produced from dimethyl ether, which itself can be manufactured from synthesis gas using Air Products' Liquid Phase Dimethyl Ether (LPDME TM) technology. CETANERTM is a liquid, has an oxygen content of 36 wt.%, has a cetane number over 100 and is highly miscible in diesel fuel. This combination of physical and chemical properties makes CETANERTM an attractive agent for oxygenating diesel fuel. The present study considered CETANERTM ratios from 0 to 40 wt.% in a California Air Resources Board (CARB) specification diesel fuel. Particulate matter emissions, gaseous emissions and in-cylinder pressure traces were monitored over the AVL 8-Mode engine test protocol [7]. This paper presents the results from these measurements and discusses the implications of using high cetane number oxygenates in diesel fuel reformulation.

Boehman, Andre L.

2000-08-20T23:59:59.000Z

298

High density adsorbed oxygen on Rh,,111... and enhanced routes to metallic oxidation using atomic oxygen  

E-Print Network [OSTI]

High density adsorbed oxygen on Rh,,111... and enhanced routes to metallic oxidation using atomic oxygen K. D. Gibson, Mark Viste, Errol C. Sanchez, and S. J. Sibener The James Franck Institute; accepted 30 November 1998 Exposure of Rh 111 to atomic oxygen leads to the facile formation of a full

Sibener, Steven

299

New Oxygen-Production Technology Proving Successful  

Broader source: Energy.gov [DOE]

The Office of Fossil Energy's National Energy Technology Laboratory has partnered with Air Products and Chemicals Inc. of Allentown, Penn. to develop the Ion Transport Membrane (ITM) Oxygen, a revolutionary new oxygen-production technology that requires less energy and offers lower capital costs than conventional technologies.

300

Oxygen and Nitrogen Contamination During Arc Welding  

E-Print Network [OSTI]

) ) : ,- Oxygen and Nitrogen Contamination During Arc Welding T. W. Eagar Department of }faterials, shielded metal arc, self-shielded metal arc, and submerged arc welding are reviewed. Calcu- lations upon heating is also discussed. Introduction Oxygen and nitrogen ~ontamination of weld metal

Eagar, Thomas W.

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

Modelling Hydrogen Reduction and Hydrodeoxygenation of Oxygenates  

SciTech Connect (OSTI)

Based on Density Functional Theory (DFT) simulations, we have studied the reduction of nickel oxide and biomass derived oxygenates (catechol, guaiacol, etc.) in hydrogen. Both the kinetic barrier and thermodynamic favorability are calculated with respect to the modeled reaction pathways. In early-stage reduction of the NiO(100) surface by hydrogen, the pull-off of the surface oxygen atom and simultaneous activation of the nearby Ni atoms coordinately dissociate the hydrogen molecules so that a water molecule can be formed, leaving an oxygen vacancy on the surface. In hydrogen reaction with oxygenates catalyzed by transition metals, hydrogenation of the aromatic carbon ring normally dominates. However, selective deoxygenation is of particular interest for practical application such as biofuel conversion. Our modeling shows that doping of the transition metal catalysts can change the orientation of oxygenates adsorbed on metal surfaces. The correlation between the selectivity of reaction and the orientation of adsorption are discussed.

Zhao, Y.; Xu, Q.; Cheah, S.

2013-01-01T23:59:59.000Z

302

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

This quarterly technical progress report will summarize work accomplished for the Program through the fourth quarter January-March 2001 in the following task areas: Task 1 - Oxygen Enhanced Combustion, Task 2 - Oxygen Transport Membranes and Task 4 - Program Management. This report will also recap the results of the past year. The program is proceeding in accordance with the objectives for the first year. OTM material characterization was completed. 100% of commercial target flux was demonstrated with OTM disks. The design and assembly of Praxair's single tube high-pressure test facility was completed. The production of oxygen with a purity of better than 99.5% was demonstrated. Coal combustion testing was conducted at the University of Arizona. Modest oxygen enhancement resulted in NOx emissions reduction. The injector for oxygen enhanced coal based reburning was conducted at Praxair. Combustion modeling with Keystone boiler was completed. Pilot-scale combustion test furnace simulations continued this quarter.

David R. Thompson; Lawrence E. Bool; Jack C. Chen

2001-04-01T23:59:59.000Z

303

Oxygen ion-conducting dense ceramic  

DOE Patents [OSTI]

Preparation, structure, and properties of mixed metal oxide compositions containing at least strontium, cobalt, iron and oxygen are described. The crystalline mixed metal oxide compositions of this invention have, for example, structure represented by Sr.sub..alpha. (Fe.sub.1-x Co.sub.x).sub..alpha.+.beta. O.sub..delta. where x is a number in a range from 0.01 to about 1, .alpha. is a number in a range from about 1 to about 4, .beta. is a number in a range upward from 0 to about 20, and .delta. is a number which renders the compound charge neutral, and wherein the composition has a non-perovskite structure. Use of the mixed metal oxides in dense ceramic membranes which exhibit oxygen ionic conductivity and selective oxygen separation, are described as well as their use in separation of oxygen from an oxygen-containing gaseous mixture.

Balachandran, Uthamalingam (Hinsdale, IL); Kleefisch, Mark S. (Naperville, IL); Kobylinski, Thaddeus P. (Lisle, IL); Morissette, Sherry L. (Las Cruces, NM); Pei, Shiyou (Naperville, IL)

1997-01-01T23:59:59.000Z

304

Oxygen ion-conducting dense ceramic  

DOE Patents [OSTI]

Preparation, structure, and properties of mixed metal oxide compositions containing at least strontium, cobalt, iron and oxygen are described. The crystalline mixed metal oxide compositions of this invention have, for example, structure represented by Sr.sub..alpha. (Fe.sub.1-x Co.sub.x).sub..alpha.+.beta. O.sub..delta. where x is a number in a range from 0.01 to about 1, .alpha. is a number in a range from about 1 to about 4, .beta. is a number in a range upward from 0 to about 20, and .delta. is a number which renders the compound charge neutral, and wherein the composition has a non-perovskite structure. Use of the mixed metal oxides in dense ceramic membranes which exhibit oxygen ionic conductivity and selective oxygen separation, are described as well as their use in separation of oxygen from an oxygen-containing gaseous mixture.

Balachandran, Uthamalingam (Hinsdale, IL); Kleefisch, Mark S. (Naperville, IL); Kobylinski, Thaddeus P. (Lisle, IL); Morissette, Sherry L. (Las Cruces, NM); Pei, Shiyou (Naperville, IL)

1996-01-01T23:59:59.000Z

305

Theory of the helium isotope shift  

E-Print Network [OSTI]

Theory of the isotope shift of the centroid energies of light few-electron atoms is reviewed. Numerical results are presented for the isotope shift of the $2^3P$-$2^3S$ and $2^1S$-$2^3S$ transition energies of $^3$He and $^4$He. By comparing theoretical predictions for the isotope shift with the experimental results, the difference of the squares of the nuclear charge radii of $^3$He and $^4$He, $\\delta R^2$, is determined with high accuracy.

Yerokhin, Vladimir A

2015-01-01T23:59:59.000Z

306

Selective photooxidation of hydrocarbons in zeolites by oxygen  

DOE Patents [OSTI]

A selective photooxidation process for the conversion of hydrocarbon molecules to partially oxygenated derivatives, which comprises the steps of adsorbing a hydrocarbon and oxygen onto a dehydrated zeolite support matrix to form a hydrocarbon-oxygen contact pair, and subsequently exposing the hydrocarbon-oxygen contact pair to visible light, thereby forming a partially oxygenated derivative.

Frei, Heinz (Berkeley, CA); Blatter, Fritz (Berkeley, CA); Sun, Hai (Berkeley, CA)

1998-01-01T23:59:59.000Z

307

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

Conventional wisdom says adding oxygen to a combustion system enhances product throughput, system efficiency, and, unless special care is taken, increases NOx emissions. This increase in NOx emissions is typically due to elevated flame temperatures associated with oxygen use leading to added thermal NOx formation. Innovative low flame temperature oxy-fuel burner designs have been developed and commercialized to minimize both thermal and fuel NOx formation for gas and oil fired industrial furnaces. To be effective these systems require close to 100% oxy-fuel combustion and the cost of oxygen is paid for by fuel savings and other benefits. For applications to coal-fired utility boilers at the current cost of oxygen, however, it is not economically feasible to use 100% oxygen for NOx control. In spite of this conventional wisdom, Praxair and its team members, in partnership with the US Department of Energy National Energy Technology Laboratory, have developed a novel way to use oxygen to reduce NOx emissions without resorting to complete oxy-fuel conversion. In this concept oxygen is added to the combustion process to enhance operation of a low NOx combustion system. Only a small fraction of combustion air is replaced with oxygen in the process. By selectively adding oxygen to a low NOx combustion system it is possible to reduce NOx emissions from nitrogen-containing fuels, including pulverized coal, while improving combustion characteristics such as unburned carbon. A combination of experimental work and modeling was used to define how well oxygen enhanced combustion could reduce NOx emissions. The results of this work suggest that small amounts of oxygen replacement can reduce the NOx emissions as compared to the air-alone system. NOx emissions significantly below 0.15 lbs/MMBtu were measured. Oxygen addition was also shown to reduce carbon in ash. Comparison of the costs of using oxygen for NOx control against competing technologies, such as SCR, show that this concept offers substantial savings over SCR and is an economically attractive alternative to purchasing NOx credits or installing other conventional technologies. In conjunction with the development of oxygen based low NOx technology, Praxair also worked on developing the economically enhancing oxygen transport membrane (OTM) technology which is ideally suited for integration with combustion systems to achieve further significant cost reductions and efficiency improvements. This OTM oxygen production technology is based on ceramic mixed conductor membranes that operate at high temperatures and can be operated in a pressure driven mode to separate oxygen with infinite selectivity and high flux. An OTM material was selected and characterized. OTM elements were successfully fabricated. A single tube OTM reactor was designed and assembled. Testing of dense OTM elements was conducted with promising oxygen flux results of 100% of target flux. However, based on current natural gas prices and stand-alone air separation processes, ceramic membranes do not offer an economic advantage for this application. Under a different DOE-NETL Cooperative Agreement, Praxair is continuing to develop oxygen transport membranes for the Advanced Boiler where the economics appear more attractive.

David R. Thompson; Lawrence E. Bool; Jack C. Chen

2004-04-01T23:59:59.000Z

308

Nonequilibrium clumped isotope signals in microbial methane  

E-Print Network [OSTI]

Methane is a key component in the global carbon cycle with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its ...

Wang, David T.

309

A SUPERCONDUCTING-SOLENOID ISOTOPE SPECTROMETER  

E-Print Network [OSTI]

A SUPERCONDUCTING-SOLENOID ISOTOPE SPECTROMETER FOR PRODUCTION OF NEUTRON-RICH NUCLEI ( 136 Xe Superconducting Cyclotron Laboratory's weekly \\Green Sheet," 30 July 1999 #12; c Thomas W. O'Donnell 2000 All

O'Donnell, Tom

310

Oxygen and Nitrogen in Leo A and GR 8  

E-Print Network [OSTI]

We present elemental abundances for multiple HII regions in Leo A and GR 8 obtained from long slit optical spectroscopy of these two nearby low luminosity dwarf irregular galaxies. As expected from their luminosities, and in agreement with previous observations, the derived oxygen abundances are extremely low in both galaxies. High signal-to-noise ratio observations of a planetary nebula in Leo A yield 12 + log(O/H) = 7.30 +/- 0.05; "semi-empirical" calculations of the oxygen abundance in four HII regions in Leo A indicate 12 + log(O/H) = 7.38 +/- 0.10. These results confirm that Leo A has one of the lowest ISM metal abundances of known nearby galaxies. Based on results from two HII regions with high signal-to-noise measurements of the weak [O III] 4363 line, the mean oxygen abundance of GR 8 is 12 + log(O/H) = 7.65 +/- 0.06; using "empirical" and "semi-empirical" methods, similar abundances are derived for 6 other GR 8 HII regions. Similar to previous results in other low metallicity galaxies, the mean log(N/O) = -1.53 +/- 0.09 for Leo A and -1.51 +/- 0.07 for GR 8. There is no evidence of significant variations in either O/H or N/O in the HII regions. The metallicity-luminosity relation for nearby (D oxygen abundances has a mean correlation of 12 + log(O/H) = 5.67 - 0.151 M_B with a dispersion in oxygen about the relationship of 0.21. These observations confirm that gas-rich low luminosity galaxies have extremely low elemental abundances in the ionized gas-phase of their interstellar media. Although Leo A has one of the lowest metal abundances of known nearby galaxies, detection of tracers of an older stellar population indicate that it is not a newly formed galaxy as has been proposed for some other similarly low metallicity star forming galaxies.

L. van Zee; E. D. Skillman; M. P. Haynes

2005-09-22T23:59:59.000Z

311

Oxygen and organic matter thresholds for benthic faunal activity on the Pakistan margin oxygen minimum zone (7001100 m)  

E-Print Network [OSTI]

Oxygen and organic matter thresholds for benthic faunal activity on the Pakistan margin oxygen increased animal activity associated with increasing bottom-water oxygen concentration. We examined faunal community responses to oxygen and organic matter gradients across the lower oxygen minimum zone (OMZ

Levin, Lisa

312

Oxygen Discharge and Post-Discharge Kinetics Experiments and Modeling for the Electric Oxygen-Iodine Laser System  

E-Print Network [OSTI]

Oxygen Discharge and Post-Discharge Kinetics Experiments and Modeling for the Electric Oxygen a low-pressure oxygen/helium/nitric oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited species adds levels

Carroll, David L.

313

Lithium in Jack Hills zircons: Evidence for extensive weathering of Earth's earliest crust Takayuki Ushikubo a,  

E-Print Network [OSTI]

Lithium in Jack Hills zircons: Evidence for extensive weathering of Earth's earliest crust Takayuki Hills lithium weathering continental crust Hadean In situ Li analyses of 4348 to 3362 Ma detrital of REEs. The Jack Hills zircons also have fractionated lithium isotope ratios (7 Li=-19 to+13) about five

Mcdonough, William F.

314

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

315

E-Print Network 3.0 - allende cv3 chondrite Sample Search Results  

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

of Geological Sciences, University of Tennessee Collection: Geosciences 9 RARE EARTH ELEMENTS AND OXYGEN ISOTOPES IN ALLENDE CHONDRULES AS EVIDENCE FOR CAI MIXING IN...

316

Characterization of an oxygen suspension used for intravenous infusion  

E-Print Network [OSTI]

Oxygenated fluid mixture can be used to treat critically ill patients suffering from asphyxia, lung injury, and cardiac arrest. This oxygenated fluid delivered intravenously re-oxygenates the bloodstream, allowing for more ...

Peña, Kristen Helen

2012-01-01T23:59:59.000Z

317

Reactive oxygen species: a breath of life or death?  

E-Print Network [OSTI]

AP1, activator protein-1; ODD, oxygen-dependent degradationSignaling response when oxygen levels decrease (Fig. 1C;3. Halliwell B. Reactive oxygen species in living sys- tems:

Fruehauf, John P; Meyskens, Frank L Jr

2007-01-01T23:59:59.000Z

318

Blood oxygen transport and depletion : the key of consummate divers  

E-Print Network [OSTI]

and Dill, D. B. (1935). Oxygen dissociation curves of birdE. (1964). A venous blood oxygen reservoir in the divingand Torrance, J. D. (1977). Oxygen-Affinity of Avian Blood.

Meir, Jessica Ulrika

2009-01-01T23:59:59.000Z

319

Imaging Intrinsic Diffusion of Bridge-Bonded Oxygen Vacancies...  

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

Intrinsic Diffusion of Bridge-Bonded Oxygen Vacancies on TiO2(110). Imaging Intrinsic Diffusion of Bridge-Bonded Oxygen Vacancies on TiO2(110). Abstract: Since oxygen atom...

320

Oxygen Tension Modulates Neurite Outgrowth in PC12 Cells Through A Mechanism Involving HIF and VEGF  

E-Print Network [OSTI]

neural repair. Keywords Oxygen tension . Neurite extension .respective physiological oxygen microenvironments (Chen etet al. 2008). For example, oxygen tension differentially

Genetos, Damian C.; Cheung, Whitney K.; Decaris, Martin L.; Leach, J. Kent

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope evidence" 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.


321

Long-term oxygen sensor implantation in the porcine subcutaneous environment  

E-Print Network [OSTI]

Membrane-­?Covered  Oxygen  Electrode.   Analytical  Microvascular  and  tissue  oxygen   distribution.  vitro  stability  of  an  oxygen  sensor.   Anal  Chem,  

Kumosa, Lucas Stefan

2011-01-01T23:59:59.000Z

322

Strontium and carbon isotope stratigraphy of the Llandovery (Early Silurian): Implications for tectonics and weathering  

E-Print Network [OSTI]

Strontium and carbon isotope stratigraphy of the Llandovery (Early Silurian): Implications online 2 June 2010 Keywords: Silurian Strontium isotopes Carbon isotopes Weathering K-bentonites A high

Saltzman, Matthew R.

323

Tetraoxygen on Reduced Ti02(110): Oxygen Adsorption and Reactions...  

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

Tetraoxygen on Reduced Ti02(110): Oxygen Adsorption and Reactions with Oxygen Vacancies. Tetraoxygen on Reduced Ti02(110): Oxygen Adsorption and Reactions with Oxygen Vacancies....

324

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...

325

Selective reduction of NOx in oxygen rich environments with plasma...  

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

reduction of NOx in oxygen rich environments with plasma-assisted catalysis: Catalyst development and mechanistic studies Selective reduction of NOx in oxygen rich environments...

326

Oxygen Diffusion (OD) Dramatically Improves Wear-Resistance of...  

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

Oxygen Diffusion (OD) Dramatically Improves Wear-Resistance of Titanium Oxygen Diffusion (OD) Dramatically Improves Wear-Resistance of Titanium 2007 Diesel Engine-Efficiency &...

327

Oxygen detected in atmosphere of Saturn's moon Dione  

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

Oxygen detected in atmosphere of Saturn's moon Dione Oxygen detected in atmosphere of Saturn's moon Dione Scientists and an international research team have announced discovery of...

328

Virtual Oxygen Sensor for Innovative NOx and PM Emission Control...  

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

Virtual Oxygen Sensor for Innovative NOx and PM Emission Control Technologies Virtual Oxygen Sensor for Innovative NOx and PM Emission Control Technologies A virtual O2 sensor for...

329

Effects of Oxygen-Containing Functional Groups on Supercapacitor...  

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

Oxygen-Containing Functional Groups on Supercapacitor Performance. Effects of Oxygen-Containing Functional Groups on Supercapacitor Performance. Abstract: Molecular dynamics (MD)...

330

Testing Oxygen Reduction Reaction Activity with the Rotating...  

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

Testing Oxygen Reduction Reaction Activity with the Rotating Disc Electrode Technique Testing Oxygen Reduction Reaction Activity with the Rotating Disc Electrode Technique...

331

Isolation, Characterization of an Intermediate in an Oxygen Atom...  

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

Characterization of an Intermediate in an Oxygen Atom-Transfer Reaction, and the Determination of the Bond Isolation, Characterization of an Intermediate in an Oxygen Atom-Transfer...

332

Direct Measurement of Oxygen Incorporation into Thin Film Oxides...  

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

Measurement of Oxygen Incorporation into Thin Film Oxides at Room Temperature Upon Ultraviolet Phton Irradiation. Direct Measurement of Oxygen Incorporation into Thin Film Oxides...

333

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...

334

Electron-Stimulated Production of Molecular Oxygen in Amorphous...  

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

Water. Electron-Stimulated Production of Molecular Oxygen in Amorphous Solid Water. Abstract: The low-energy, electron-stimulated production of molecular oxygen from pure amorphous...

335

Bimetallic and Ternary Alloys for Improved Oxygen Reduction Catalysis...  

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

Bimetallic and Ternary Alloys for Improved Oxygen Reduction Catalysis . Bimetallic and Ternary Alloys for Improved Oxygen Reduction Catalysis . Abstract: The research described in...

336

Advantages of Oxygenates Fuels over Gasoline in Direct Injection...  

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

Advantages of Oxygenates Fuels over Gasoline in Direct Injection Spark Ignition Engines Advantages of Oxygenates Fuels over Gasoline in Direct Injection Spark Ignition Engines...

337

Reactive Gliosis Reactive Oxygen Species: Superoxide  

E-Print Network [OSTI]

. By sensing the electric signals generated by other 3368 Reactive Gliosis #12;individuals, mormyrids are alsoReactive Gliosis Glial Scar Reactive Oxygen Species: Superoxide Anions Neuroinflammation motor output. Reafferent Control in Electric Communication Reafferent Control in Electric Communication

338

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

This quarterly technical progress report will summarize work accomplished for the Program through the thirteenth quarter, April-June 2003, in the following task areas: Task 1--Oxygen Enhanced Combustion, Task 3--Economic Evaluation and Task 4--Program Management. The program is proceeding in accordance with project objectives. REI's model was modified to evaluate mixing issues in the upper furnace of a staged unit. Analysis of the results, and their potential application to this unit is ongoing. Economic evaluation continues to confirm the advantage of oxygen-enhanced combustion. A contract for a commercial demonstration has been signed with the Northeast Generation Services Company to supply oxygen and license the oxygen enhanced low NOx combustor technology for use at the 147-megawatt coal fired Mt. Tom Station in Holyoke, MA. Commercial proposals have been submitted. Economic analysis of a beta site test performance was conducted.

David R. Thompson; Lawrence E. Bool; Jack C. Chen

2003-08-01T23:59:59.000Z

339

Design optimization of oxygenated fluid pump  

E-Print Network [OSTI]

In medical emergencies, an oxygen-starved brain quickly suffers irreparable damage. In many cases, patients who stop breathing can be resuscitated but suffer from brain damage. Dr. John Kheir from Boston Children's Hospital ...

Piazzarolo, Bruno Aiala

2012-01-01T23:59:59.000Z

340

Electron-impact excitation of neutral oxygen  

E-Print Network [OSTI]

Aims: To calculate transition rates from ground and excited states in neutral oxygen atoms due to electron collisions for non-LTE modelling of oxygen in late-type stellar atmospheres, thus enabling reliable interpretation of oxygen lines in stellar spectra. Methods: A 38-state R-matrix calculation in LS-coupling has been performed. Basis orbitals from the literature (Thomas et al.) are adopted, and a large set of configurations are included to obtain good representations of the target wavefunctions. Rate coefficients are calculated by averaging over a Maxwellian velocity distribution. Results: Estimates for the cross sections and rate coefficients are presented for transitions between the seven lowest LS states of neutral oxygen. The cross sections for excitation from the ground state compare well with existing experimental and recent theoretical results.

P. S. Barklem

2006-09-25T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

Injectable polymer for in vivo oxygen sensing  

E-Print Network [OSTI]

This thesis documents the synthesis and characterization of an elastomeric polymer that is oxygen sensitive and can be interrogated using Magnetic Resonance Imaging (MRI) or Magnetic Resonance (MR) technology to report the ...

Imaad, Syed M. (Syed Muhammad)

2013-01-01T23:59:59.000Z

342

Oxygen Enriched Combustion System Performance Study  

E-Print Network [OSTI]

}ched combustlon systems are technically, envlronmentally and economically feasible and offer significant energy savings and/or productivity improvement, and then to verify the performance of selected systems in research furnaces. Tests of several commercial... for 35 - 100 percent oxygen. The absolute levels of the NO x emissions also depended on the furnace temperature. INTRODUCTION Oxygen enriched combustion has been found to have significant energy saving potential in industrial furnace applications...

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

343

UW Cosmogenic Isotopes Al-Be 1 EXTRACTION OF Al & Be FROM QUARTZ FOR ISOTOPIC ANALYSIS  

E-Print Network [OSTI]

UW Cosmogenic Isotopes Al-Be 1 EXTRACTION OF Al & Be FROM QUARTZ FOR ISOTOPIC ANALYSIS Summary This method is used to separate Al and Be for AMS analysis from pure quartz samples. After adding Be carrier, quartz is dissolved in HF. The solution is sub-sampled for determination of total Al content, then dried

Stone, John

344

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

This quarterly technical progress report will summarize work accomplished for the Program in the seventh quarter October-December 2001 in the following task areas: Task 1 - Oxygen Enhanced Combustion, Task 2 - Oxygen Transport Membranes, Task 3 - Economic Evaluation and Task 4 - Program Management. Computational fluid dynamic (CFD) modeling of oxygen injection strategies was performed during the quarter resulting in data that suggest the oxygen injection reduces NOx emissions while reducing LOI. Pilot-scale testing activities concluded at the University of Utah this quarter. Testing demonstrated that some experimental conditions can lead to NOx emissions well below the 0.15 lb/MMBtu limit. Evaluation of alternative OTM materials with improved mechanical properties continued this quarter. Powder procedure optimization continued and sintering trial began on an element with a new design. Several OTM elements were tested in Praxair's single tube high-pressure test facility under various conditions. A modified PSO1d element demonstrated stable oxygen product purity of >98% and oxygen flux of 68% of target. Updated test results and projected economic performance have been reviewed with the Utility Industrial Advisors. The economic comparison remains very favorable for O{sub 2} enhanced combustion. Discussions regarding possible Beta sites have been held with three other utilities in addition to the industrial advisors. Proposals will be prepared after the completion of full scale burner testing. Beta test cost estimating work has been initiated.

David R. Thompson; Lawrence E. Bool; Jack C. Chen

2002-01-01T23:59:59.000Z

345

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

This quarterly technical progress report will summarize work accomplished for the Program through the fourth quarter January-March 2002 in the following task areas: Task 1--Oxygen Enhanced Combustion, Task 2--Oxygen Transport Membranes, Task 3--Economic Evaluation and Task 4--Program Management. This report will also recap the results of the past year. The program is proceeding in accordance with the objectives for the second year. The first round of pilot scale testing with 3 bituminous coals was completed at the University of Utah. Full-scale testing equipment is in place and experiments are underway. Coal combustion lab-scale testing was completed at the University of Arizona. Modest oxygen enhancement resulted in NOx emissions reduction. Combustion modeling activities continued with pilot-scale combustion test furnace simulations. 75% of target oxygen flux was demonstrated with small PSO1 tube in Praxair's single tube high-pressure test facility. The production of oxygen with a purity of better than 99.999% was demonstrated. Economic evaluation has confirmed the advantage of oxygen-enhanced combustion. Two potential host sites have been identified.

David R. Thompson; Lawrence E. Bool; Jack C. Chen

2002-04-01T23:59:59.000Z

346

Magnetism in Lithium–Oxygen Discharge Product  

SciTech Connect (OSTI)

Nonaqueous lithium–oxygen batteries have a much superior theoretical gravimetric energy density compared to conventional lithium-ion batteries, and thus could render long-range electric vehicles a reality. A molecular-level understanding of the reversible formation of lithium peroxide in these batteries, the properties of major/minor discharge products, and the stability of the nonaqueous electrolytes is required to achieve successful lithium–oxygen batteries. We demonstrate that the major discharge product formed in the lithium–oxygen cell, lithium peroxide, exhibits a magnetic moment. These results are based on dc-magnetization measurements and a lithium– oxygen cell containing an ether-based electrolyte. The results are unexpected because bulk lithium peroxide has a significant band gap. Density functional calculations predict that superoxide- type surface oxygen groups with unpaired electrons exist on stoichiometric lithium peroxide crystalline surfaces and on nanoparticle surfaces; these computational results are consistent with the magnetic measurement of the discharged lithium peroxide product as well as EPR measurements on commercial lithium peroxide. The presence of superoxide-type surface oxygen groups with spin can play a role in the reversible formation and decomposition of lithium peroxide as well as the reversible formation and decomposition of electrolyte molecules.

Lu, Jun; Jung, Hun-Ji; Lau, Kah Chun; Zhang, Zhengcheng; Schlueter, John A.; Du, Peng; Assary, Rajeev S.; Greeley, Jeffrey P.; Ferguson, Glen A.; Wang, Hsien-Hau; Hassoun, Jusef; Iddir, Hakim; Zhou, Jigang; Zuin, Lucia; Hu, Yongfeng; Sun, Yang-Kook; Scrosati, Bruno; Curtiss, Larry A.; Amine, Khalil

2013-05-13T23:59:59.000Z

347

Atomic Oxygen in the Comae of Comets  

E-Print Network [OSTI]

We report on the detection of atomic oxygen lines in the spectra of 8 comets. These forbidden lines are a result of the photodissociation of the parent oxygen-bearing species directly into an excited state. We used high resolution spectra obtained at the McDonald Observatory 2.7m telescope to resolve the cometary oxygen lines from the telluric oxygen lines and from other cometary emissions. We find that the relative intensities of the two red lines (6300.304 and 6363.776A) are consistent with theory. The green line (5577.339A) has an intensity which is about 10% of the sum of the intensities of the two red lines. We show that collisional quenching may be important in the inner coma. If we assume the relative excitation rates of potential parents which have appeared in the literature, then H2O would be the parent of the cometary green oxygen line. However, those rates have been questioned. We measured the width of the three oxygen lines and find that the green line is wider than either of the two red lines. The finding of a wider line could imply a different parent for the green and red lines. However, the constancy of the green to red line flux ratio suggests the parent is the same for these lines but that the exciting photons have different energies.

Anita L. Cochran

2008-07-03T23:59:59.000Z

348

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

Increased environmental regulations will require utility boilers to reduce NO{sub x} emissions to less than 0.15lb/MMBtu in the near term. Conventional technologies such as Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) are unable to achieve these lowered emission levels without substantially higher costs and major operating problems. Oxygen enhanced combustion is a novel technology that allows utilities to meet the NO{sub x} emission requirements without the operational problems that occur with SCR and SNCR. Furthermore, oxygen enhanced combustion can achieve these NO{sub x} limits at costs lower than conventional technologies. The objective of this program is to demonstrate the use of oxygen enhanced combustion as a technical and economical method of meeting the EPA State Implementation Plan for NO{sub x} reduction to less than 0.15lb/MMBtu for a wide range of boilers and coal. The oxygen enhanced coal combustion program (Task 1) focused this quarter on the specific objective of exploration of the impact of oxygen enrichment on NO{sub x} formation utilizing small-scale combustors for parametric testing. Research efforts toward understanding any limitations to the applicability of the technology to different burners and fuels such as different types of coal are underway. The objective of the oxygen transport membrane (OTM) materials development program (Task 2.1) is to ascertain a suitable material composition that can be fabricated into dense tubes capable of producing the target oxygen flux under the operating conditions. This requires that the material have sufficient oxygen permeation resulting from high oxygen ion conductivity, high electronic conductivity and high oxygen surface exchange rate. The OTM element development program (Task 2.2) objective is to develop, fabricate and characterize OTM elements for laboratory and pilot reactors utilizing quality control parameters to ensure reproducibility and superior performance. A specific goal is to achieve a material that will sinter to desired density without compromising other variables such as reaction to binder systems or phase purity. Oxygen-enhanced combustion requires a facility which is capable of supplying high purity oxygen (>99.5%) at low costs. This goal can be achieved through the thermal integration of high temperature air separation with ceramic OTM. The objective of the OTM process development program (Task 2.3) is to demonstrate successfully the program objectives on a lab-scale single OTM tube reactor under process conditions comparable to those of an optimum large-scale oxygen facility. This quarterly technical progress report will summarize work accomplished for the Program through the first quarter April--June 2000 in the following task areas: Task 1 Oxygen Enhanced Coal Combustion; Task 2 Oxygen Transport Membranes; and Task 4 Program Management.

Lawrence E. Bool; Jack C. Chen; David R. Thompson

2000-07-01T23:59:59.000Z

349

Oxygen generator for medical applications (USIC)  

SciTech Connect (OSTI)

The overall Project objective is to develop a portable, non-cryogenic oxygen generator capable of supplying medical grade oxygen at sufficient flow rates to allow the field application of the Topical Hyperbaric Oxygen Therapy (THOT{reg_sign}) developed by Numotech, Inc. This project was sponsored by the U.S. Department of Energy Global Initiatives for Proliferation Prevention (GIPP) and is managed by collaboration between Sandia National Laboratories (SNL), Numotech, Inc, and LLC SPE 'Spektr-Conversion.' The project had two phases, with the objective of Phase I being to develop, build and test a laboratory prototype of the membrane-pressure swing adsorber (PSA) system producing at 15 L/min of oxygen with a minimum of 98% oxygen purity. Phase II objectives were to further refine and identify the pre-requisites needed for a commercial product and to determine the feasibility of producing 15 L/min of oxygen with a minimum oxygen purity of 99%. In Phase I, Spektr built up the necessary infrastructure to perform experimental work and proceeded to build and demonstrate a membrane-PSA laboratory prototype capable of producing 98% purity oxygen at a flow rate of 5 L/min. Spektr offered a plausible path to scale up the process for 15 L/min. Based on the success and experimental results obtained in Phase I, Spektr performed work in three areas for Phase II: construction of a 15 L/min PSA; investigation of compressor requirements for the front end of the membrane/PSA system; and performing modeling and simulation of assess the feasibility of producing oxygen with a purity greater than 99%. Spektr successfully completed all of the tasks under Phase II. A prototype 15 L/min PSA was constructed and operated. Spektr determined that no 'off the shelf' air compressors met all of the specifications required for the membrane-PSA, so a custom compressor will likely need to be built. Modeling and simulation concluded that production of oxygen with purities greater than 99% was possible using a Membrane-PSA system.

Staiger, C. L.

2012-03-01T23:59:59.000Z

350

Laser Isotope Separation Employing Condensation Repression  

SciTech Connect (OSTI)

Molecular laser isotope separation (MLIS) techniques using condensation repression (CR) harvesting are reviewed and compared with atomic vapor laser isotope separation (AVLIS), gaseous diffusion (DIF), ultracentrifuges (UCF), and electromagnetic separations (EMS). Two different CR-MLIS or CRISLA (Condensation Repression Isotope Separation by Laser Activation) approaches have been under investigation at the University of Missouri (MU), one involving supersonic super-cooled free jets and dimer formation, and the other subsonic cold-wall condensation. Both employ mixtures of an isotopomer (e.g. {sup i}QF{sub 6}) and a carrier gas, operated at low temperatures and pressures. Present theories of VT relaxation, dimerization, and condensation are found to be unsatisfactory to explain/predict experimental CRISLA results. They were replaced by fundamentally new models that allow ab-initio calculation of isotope enrichments and predictions of condensation parameters for laser-excited and non-excited vapors which are in good agreement with experiment. Because of supersonic speeds, throughputs for free-jet CRISLA are a thousand times higher than cold-wall CRISLA schemes, and thus preferred for large-quantity Uranium enrichments. For small-quantity separations of (radioactive) medical isotopes, the simpler coldwall CRISLA method may be adequate.

Eerkens, Jeff W.; Miller, William H.

2004-09-15T23:59:59.000Z

351

Surface Exchange and Bulk Diffusivity of LSCF as SOFC Cathode: Electrical Conductivity Relaxation and Isotope Exchange Characterizations  

SciTech Connect (OSTI)

The oxygen diffusion coefficient (D) and surface exchange coefficient (k) of a typical SOFC cathode material, La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-?} (LSCF) were characterized by both electrical conductivity relaxation (ECR) and oxygen isotope exchange (IE) methods. Conductivity relaxation experiments were conducted at 800°C for small step changes in partial pressure of oxygen (P{sub O{sub 2}} ), both decreasing and increasing, from 0.02 atm to 0.20 atm. The results revealed P{sub O{sub 2}} dependent hysteresis with the reduction process requiring more equilibration time than oxidation. Analysis of the experimental data indicated that the surface exchange coefficient is a function of the final oxygen partial pressure in an isothermal system. In addition, both forward and backward oxygen reduction reaction constants, which are vital for the fundamental understanding of SOFC cathode reaction mechanisms, are investigated based on the relationship between surface exchange coefficient and P{sub O{sub 2}} . The direct comparisons between the results from both ECR and IE were presented and the possible experimental errors in both methods were discussed.

Li, Yihong; Gerdes, Kirk; Horita, Teruhisa; Liu, Xingbo

2013-05-05T23:59:59.000Z

352

Evidence of Southern Health  

E-Print Network [OSTI]

POS Evidence of Coverage Southern Health Services, Inc. SH.POS.11-09 #12;Table of Contents SH................................................................................................10 Facts about Southern Health .....................................................................12 Members' Responsibilities to Know How and When to Seek Care ............................13 Section

Acton, Scott

353

Dissecting Oxygenic Photosynthesis: The Evolution of the "Z"-Scheme  

E-Print Network [OSTI]

of the "period four oxygen clock" and the structure of the oxygen-evolving center. After a brief mention the maximum quantum yield, i.e., the number of oxygen molecules evolved per photon of light absorbed11CHAPTER Dissecting Oxygenic Photosynthesis: The Evolution of the "Z"-Scheme for Thylakoid

Govindjee

354

Oxygen Toxicity Calculations by Erik C. Baker, P.E.  

E-Print Network [OSTI]

1 Oxygen Toxicity Calculations by Erik C. Baker, P.E. Management of exposure to oxygen toxicity myself using the good ole' FORTRAN programming language, I found that incorporating oxygen toxicity for others. Background Two oxygen toxicity parameters are typically "tracked" in technical diving

Read, Charles

355

Energetic neutral atoms at Mars 4. Imaging of planetary oxygen  

E-Print Network [OSTI]

Energetic neutral atoms at Mars 4. Imaging of planetary oxygen S. Barabash and M. Holmstro of the Martian oxygen exosphere/corona results in the production of planetary oxygen ions. The newborn ions start. The oxygen ions can then charge exchange with the neutral gases (H, H2, and O) of the Martian exosphere

Lukyanov, Alex

356

Atomic line emission analyzer for hydrogen isotopes  

DOE Patents [OSTI]

Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using a metal hydride.

Kronberg, James W. (108 Independent Blvd., Aiken, SC 29801)

1993-01-01T23:59:59.000Z

357

Atomic line emission analyzer for hydrogen isotopes  

DOE Patents [OSTI]

Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using, a metal hydride.

Kronberg, J.W.

1991-05-08T23:59:59.000Z

358

Apparatus for separating and recovering hydrogen isotopes  

DOE Patents [OSTI]

An apparatus for recovering hydrogen and separating its isotopes. The apparatus includes a housing bearing at least a fluid inlet and a fluid outlet. A baffle is disposed within the housing, attached thereto by a bracket. A hollow conduit is coiled about the baffle, in spaced relation to the baffle and the housing. The coiled conduit is at least partially filled with a hydride. The hydride can be heated to a high temperature and cooled to a low temperature quickly by circulating a heat transfer fluid in the housing. The spacing between the baffle and the housing maximizes the heat exchange rate between the fluid in the housing and the hydride in the conduit. The apparatus can be used to recover hydrogen isotopes (protium, deuterium and tritium) from gaseous mixtures, or to separate hydrogen isotopes from each other.

Heung, Leung K. (Aiken, SC)

1994-01-01T23:59:59.000Z

359

Atomic line emission analyzer for hydrogen isotopes  

DOE Patents [OSTI]

Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using a metal hydride.

Kronberg, J.W.

1993-03-30T23:59:59.000Z

360

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

This quarterly technical progress report will summarize work accomplished for the Program through the eleventh quarter, October-December 2002, in the following task areas: Task 1 - Oxygen Enhanced Combustion, Task 2 - Oxygen Transport Membranes, Task 3 - Economic Evaluation and Task 4 - Program Management. The program is proceeding in accordance with the objectives for the third year. Pilot scale experiments conducted at the University of Utah were aimed at confirming the importance of oxygen injection strategy for different types of burners. CFD modeling at REI was used to better understand the potential for increased corrosion under oxygen enhanced combustion conditions. Data from a full-scale demonstration test in Springfield, MO were analyzed. OTM element development continued with preliminary investigation of an alternative method of fabrication of PSO1d elements. OTM process development continued with long-term testing of a PSO1d element. Economic evaluation has confirmed the advantage of oxygen-enhanced combustion. Proposals have been submitted for two additional beta test sites. A first commercial proposal has been submitted. Economic analysis of a beta site test performance was conducted.

David R. Thompson; Lawrence E. Bool; Jack C. Chen

2003-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

This quarterly technical progress report will summarize work accomplished for the Program through the twelfth quarter, January-March 2003, in the following task areas: Task 1--Oxygen Enhanced Combustion, Task 2--Oxygen Transport Membranes, Task 3--Economic Evaluation and Task 4--Program Management. The program is proceeding in accordance with the objectives for the third year. Pilot scale experiments conducted at the University of Utah explored both the effectiveness of oxygen addition and the best way to add oxygen with a scaled version of Riley Power's newest low NOx burner design. CFD modeling was done to compare the REI's modeling results for James River Unit 3 with the NOx and LOI results obtained during the demonstration program at that facility. Investigation of an alternative method of fabrication of PSO1d elements was conducted. OTM process development work has concluded with the completion of a long-term test of a PSO1d element Economic evaluation has confirmed the advantage of oxygen-enhanced combustion. Proposals have been submitted for two additional beta test sites. Commercial proposals have been submitted. Economic analysis of a beta site test performance was conducted.

David R. Thompson; Lawrence E. Bool; Jack C. Chen

2003-04-01T23:59:59.000Z

362

Oxygenates du`jour...MTBE? Ethanol? ETBE?  

SciTech Connect (OSTI)

There are many different liquids that contain oxygen which could be blended into gasoline. The ones that have been tried and make the most sense are in the alcohol (R-OH) and ether (R-O-R) chemical family. The alcohols considered are: methanol (MeOH), ethanol (EtOH), tertiary butyl alcohol (TBA). The ethers are: methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary amyl ethyl ether (TAEE), di-isopropyl ether (DIPE). Of the eight oxygenates listed above, the author describes the five that are still waiting for widespread marketing acceptance (methanol, TBA, TAME, TAEE, and DIPE). He then discusses the two most widely used oxygenates in the US, MTBE and ethanol, along with the up-and-coming ethanol ether, ETBE. Selected physical properties for all of these oxygenates can be found in Table 2 at the end of this paper. A figure shows a simplified alcohol/ether production flow chart for the oxygenates listed above and how they are interrelated.

Wolfe, R.

1995-12-31T23:59:59.000Z

363

Oxygen abundance of open cluster dwarfs  

E-Print Network [OSTI]

We present oxygen abundances of dwarfs in the young open cluster IC 4665 deduced from the OI $\\lambda$7774 triplet lines and of dwarfs in the open cluster Pleiades derived from the [OI] $\\lambda$6300 forbidden line. Stellar parameters and oxygen abundances were derived using the spectroscopic synthesis tool SME (Spectroscopy Made Easy). We find a dramatic increase in the upper boundary of the OI triplet abundances with decreasing temperature in the dwarfs of IC 4665, consistent with the trend found by Schuler et al. in the open clusters Pleiades and M 34, and to a less extent in the cool dwarfs of Hyades (Schuler et al. 2006a) and UMa (King & Schuler 2005). By contrast, oxygen abundances derived from the [OI] $\\lambda$6300 forbidden line for stars in Pleiades and Hyades (Schuler et al. 2006b) are constant within the errors. Possible mechanisms that may lead a varying oxygen triplet line abundance are examined, including systematic errors in the stellar parameter determinations, the NLTE effects, surface activities and granulation. The age-related effects stellar surface activities (especially the chromospheric activities) are suggested by our analysis to blame for the large spreads of oxygen triplet line abundances.

Z. -X. Shen; X. -W. Liu; H. -W. Zhang; B. Jones; D. N. C. Lin

2007-03-30T23:59:59.000Z

364

Oxygen-Reducing Biocathodes Operating with Passive Oxygen Transfer in Microbial Fuel Cells  

E-Print Network [OSTI]

Oxygen-Reducing Biocathodes Operating with Passive Oxygen Transfer in Microbial Fuel Cells Xue Xia, Justin C. Tokash, Fang Zhang, Peng Liang, Xia Huang,*, and Bruce E. Logan*,, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P

365

Method for production of an isotopically enriched compound  

DOE Patents [OSTI]

A method is presented for producing and isolating an isotopically enriched compound of a desired isotope from a parent radionuclide. The method includes forming, or placing, a precipitate containing a parent radionuclide of the desired daughter isotope in a first reaction zone and allowing sufficient time for the parent to decay into the desired gaseous daughter radioisotope. The method further contemplates collecting the desired daughter isotope as a solid in a second reaction zone through the application of temperatures below the freezing point of the desired isotope to a second reaction zone that is connected to the first reaction zone. Specifically, a method is presented for producing isotopically enriched compounds of xenon, including the radioactive isotope Xe-131m and the stable isotope Xe-131.

Watrous, Matthew G.

2012-12-11T23:59:59.000Z

366

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

367

Laser isotope separation by multiple photon absorption  

DOE Patents [OSTI]

Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO[sub 2] laser light may be used to highly enrich [sup 34]S in natural SF[sub 6] and [sup 11]B in natural BCl[sub 3]. 8 figs.

Robinson, C.P.; Rockwood, S.D.; Jensen, R.J.; Lyman, J.L.; Aldridge, J.P. III.

1987-04-07T23:59:59.000Z

368

Laser isotope separation by multiple photon absorption  

DOE Patents [OSTI]

Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

Robinson, C. Paul (Los Alamos, NM); Rockwood, Stephen D. (Los Alamos, NM); Jensen, Reed J. (Los Alamos, NM); Lyman, John L. (Los Alamos, NM); Aldridge, III, Jack P. (Los Alamos, NM)

1987-01-01T23:59:59.000Z

369

Isotopic abundance in atom trap trace analysis  

DOE Patents [OSTI]

A method and system for detecting ratios and amounts of isotopes of noble gases. The method and system is constructed to be able to measure noble gas isotopes in water and ice, which helps reveal the geological age of the samples and understand their movements. The method and system uses a combination of a cooled discharge source, a beam collimator, a beam slower and magneto-optic trap with a laser to apply resonance frequency energy to the noble gas to be quenched and detected.

Lu, Zheng-Tian; Hu, Shiu-Ming; Jiang, Wei; Mueller, Peter

2014-03-18T23:59:59.000Z

370

Isotope Research Materials Laboratory | ornl.gov  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFunInfrared LandResponsesIon/SurfacePump-Testing Sign InIsotope ProgramIsotope

371

Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Geothermal...  

Open Energy Info (EERE)

navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Geothermal Area (Phillips, 2004)...

372

Isotopic Analysis At Lassen Volcanic National Park Area (Janik...  

Open Energy Info (EERE)

navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At Lassen Volcanic National Park Area (Janik & Mclaren, 2010) Exploration Activity...

373

Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Geothermal...  

Open Energy Info (EERE)

navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Geothermal Area (Ito & Tanaka, 1995)...

374

Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Area...  

Open Energy Info (EERE)

navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Area (Ito & Tanaka, 1995) Exploration...

375

Isotopic Analysis At Valles Caldera - Redondo Geothermal Area...  

Open Energy Info (EERE)

navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis At Valles Caldera - Redondo Geothermal Area (Phillips, 2004) Exploration Activity...

376

Isotopic Analysis- Gas At Dixie Valley Geothermal Area (Kennedy...  

Open Energy Info (EERE)

search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Gas At Dixie Valley Geothermal Area (Kennedy & Soest, 2006) Exploration Activity Details...

377

Oxygen: From Environment to Genes. The periodic occurrence of oxygen minima can powerfully influence organisms living in near  

E-Print Network [OSTI]

Oxygen: From Environment to Genes. The periodic occurrence of oxygen minima can powerfully to the winter of 2014. Their scholarly work is presented in this collection. #12;1 Oxygen: From Environment", 2013, 2014 Table of contents Page 2. Laura Lilly - Low-oxygen formation along the California current. 6

378

Interaction of light with the ZnO surface: Photon induced oxygen "breathing," oxygen vacancies, persistent photoconductivity,  

E-Print Network [OSTI]

Interaction of light with the ZnO surface: Photon induced oxygen "breathing," oxygen vacancies donation of oxygen vacancies. Our findings suggest that the observed decomposition of the ZnO lattice may. The formation of oxygen-vacancy rich surface is suggested to induce surface delta doping, causing accumulation

Shalish, Ilan

379

Photochemical Escape of Oxygen from Early Mars  

E-Print Network [OSTI]

Photochemical escape is an important process for oxygen escape from present Mars. In this work, a 1-D Monte-Carlo Model is developed to calculate escape rates of energetic oxygen atoms produced from O2+ dissociative recombination reactions (DR) under 1, 3, 10, and 20 times present solar XUV fluxes. We found that although the overall DR rates increase with solar XUV flux almost linearly, oxygen escape rate increases from 1 to 10 times present solar XUV conditions but decreases when increasing solar XUV flux further. Analysis shows that atomic species in the upper thermosphere of early Mars increases more rapidly than O2+ when increasing XUV fluxes. While the latter is the source of energetic O atoms, the former increases the collision probability and thus decreases the escape probability of energetic O. Our results suggest that photochemical escape be a less important escape mechanism than previously thought for the loss of water and/or CO2 from early Mars.

Zhao, Jinjin

2015-01-01T23:59:59.000Z

380

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

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

Discovery of dysprosium, holmium, erbium, thulium, and ytterbium isotopes  

SciTech Connect (OSTI)

Currently, thirty-one dysprosium, thirty-two holmium, thirty-two erbium, thirty-three thulium, and thirty-one ytterbium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

Fry, C.; Thoennessen, M., E-mail: thoennessen@nscl.msu.edu

2013-09-15T23:59:59.000Z

382

Discovery of palladium, antimony, tellurium, iodine, and xenon isotopes  

SciTech Connect (OSTI)

Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty xenon isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

Kathawa, J.; Fry, C.; Thoennessen, M., E-mail: thoennessen@nscl.msu.edu

2013-01-15T23:59:59.000Z

383

Discovery of the astatine, radon, francium, and radium isotopes  

SciTech Connect (OSTI)

Thirty-nine astatine, thirty-nine radon, thirty-five francium, and thirty-four radium isotopes have so far been observed; the discovery of these isotopes is described. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

Fry, C.; Thoennessen, M., E-mail: thoennessen@nscl.msu.edu

2013-09-15T23:59:59.000Z

384

Discovery of samarium, europium, gadolinium, and terbium isotopes  

SciTech Connect (OSTI)

Currently, thirty-four samarium, thirty-four europium, thirty-one gadolinium, and thirty-one terbium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

May, E.; Thoennessen, M., E-mail: thoennessen@nscl.msu.edu

2013-01-15T23:59:59.000Z

385

Discovery of Rubidium, Strontium, Molybdenum, and Rhodium Isotopes  

E-Print Network [OSTI]

Currently, thirty-one rubidium, thirty-five strontium, thirty-five molybdenum and thirty-eight rhodium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

Parker, A M

2011-01-01T23:59:59.000Z

386

Discovery of rubidium, strontium, molybdenum, and rhodium isotopes  

SciTech Connect (OSTI)

Currently, 31 rubidium, 35 strontium, 35 molybdenum, and 38 rhodium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

Parker, A.M.; Thoennessen, M., E-mail: thoennessen@nscl.msu.edu

2012-07-15T23:59:59.000Z

387

Discovery of Rubidium, Strontium, Molybdenum, and Rhodium Isotopes  

E-Print Network [OSTI]

Currently, thirty-one rubidium, thirty-five strontium, thirty-five molybdenum and thirty-eight rhodium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

A. M. Parker; M. Thoennessen

2011-02-11T23:59:59.000Z

388

Discovery of the actinium, thorium, protactinium, and uranium isotopes  

E-Print Network [OSTI]

Currently, 31 actinium, 31 thorium, 28 protactinium, and 23 uranium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

C. Fry; M. Thoennessen

2012-03-06T23:59:59.000Z

389

Discovery of Chromium, Manganese, Nickel, and Copper Isotopes  

E-Print Network [OSTI]

Twenty-seven chromium, twenty-five manganese, thirty-one nickel and twenty-six copper isotopes have so far been observed and the discovery of these isotopes is discussed. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

K. Garofali; R. Robinson; M. Thoennessen

2010-12-07T23:59:59.000Z

390

Discovery of Cesium, Lanthanum, Praseodymium and Promethium Isotopes  

E-Print Network [OSTI]

Currently, forty-one cesium, thirty-five lanthanum, thirty-two praseodymium, and thirty-one promethium, isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

May, E

2011-01-01T23:59:59.000Z

391

Discovery of Cesium, Lanthanum, Praseodymium and Promethium Isotopes  

E-Print Network [OSTI]

Currently, forty-one cesium, thirty-five lanthanum, thirty-two praseodymium, and thirty-one promethium, isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

E. May; M. Thoennessen

2011-09-08T23:59:59.000Z

392

Hydrogen isotope fractionation during lipid biosynthesis by Tetrahymena thermophila  

E-Print Network [OSTI]

Hydrogen isotope fractionation during lipid biosynthesis by Tetrahymena thermophila Sitindra S Accepted 7 September 2013 Available online 16 September 2013 a b s t r a c t Hydrogen isotope ratio values from recording the hydrogen isotope composition of ambient water, dD values of lipids also depend

393

ALS Evidence Confirms Combustion Theory  

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

ALS Evidence Confirms Combustion Theory ALS Evidence Confirms Combustion Theory Print Wednesday, 22 October 2014 11:43 Researchers recently uncovered the first step in the process...

394

A review of stable water isotopeA review of stable water isotope modellingmodelling  

E-Print Network [OSTI]

fractionation · Kinetic fractionation 2. Modelling the stable water isotope cycle · Rayleigh distillation model Institution of Oceanography) Harald SODEMANN (Norwegian Institute for Air Research) Kristof 18Ovapour=-40 18Oocean=0 18Osnow=-3018Orain=-2 Equilibrium fractionationEquilibrium fractionation

Sturm, Christophe "Kristof"

395

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

SciTech Connect (OSTI)

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

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

1988-01-01T23:59:59.000Z

396

Isotope-labeled immunoassays without radiation waste  

E-Print Network [OSTI]

of California, Davis, CA 95616; and Center for Accelerator Mass Spectrometry, Lawrence Livermore National, such as liquid scintillation counting (LSC) and autoradiography, use the radiation generated in the isotope in areas such as environmental monitoring and food analysis. Accelerator mass spectrometry (AMS) developed

Hammock, Bruce D.

397

Radiation Sources External Beam and Isotopes  

E-Print Network [OSTI]

Radiation Sources External Beam and Isotopes J. Daniel Bourland, PhD Professor Department of Radiation Oncology Departments of Physics and Biomedical Engineering Wake Forest School of Medicine Winston Radiation · Photons: electromagnetic radiation, no mass, E = h · X rays: origins are from atomic energy

398

Review of hydrogen isotope permeability through materials  

SciTech Connect (OSTI)

This report is the first part of a comprehensive summary of the literature on hydrogen isotope permeability through materials that do not readily form hydrides. While we mainly focus on pure metals with low permeabilities because of their importance to tritium containment, we also give data on higher-permeability materials such as iron, nickel, steels, and glasses.

Steward, S.A.

1983-08-15T23:59:59.000Z

399

Trace Element and Isotopic Fluxes/ Subducted Slab  

E-Print Network [OSTI]

3.20.7.2.1 Devolatilization 34 3.20.7.2.2 Boron and lithium isotopes 35 3.20.7.3 Carbon and Nitrogen forearcs. In addi- tion, subduction erosion from the forearc hanging walls can impact geochemical evolut

Bebout, Gray E.

400

5, 547577, 2008 Isotope hydrology of  

E-Print Network [OSTI]

HESSD 5, 547­577, 2008 Isotope hydrology of cave dripwaters L. Fuller et al. Title Page Abstract.hydrol-earth-syst-sci-discuss.net/5/547/2008/ © Author(s) 2008. This work is licensed under a Creative Commons License. Hydrology and Earth System Sciences Discussions Papers published in Hydrology and Earth System Sciences Discussions

Boyer, Edmond

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

Radioactive isotopes in Danish drinking water  

E-Print Network [OSTI]

Radioactive isotopes in Danish drinking water Sven P. Nielsen Risø National Laboratory Working OF INVESTIGATION 11 3 DESCRIPTION OF INVESTIGATION 12 4 RADIOACTIVITY IN DRINKING WATER 13 5 SAMPLING 15 6 27 #12;4 #12;5 Preface This project for investigation of radioactivity in drinking water shall

402

Carbon IsotopesCarbon Isotopes A Short Course VU March, 2009  

E-Print Network [OSTI]

. Historical CO2 record from the Vostok ice core. In Trends: A Compendium of Data on Global Change. Carbon · Bitumen · Coal Range of Carbon Isotopes PDB Hoefs 1982 #12;2/25/2009 3 Range of Carbon Isotopes PDB Hoefs 1982 12CO2 Photosynthesis 12CO2 Respiration 13CO2 CO2+ RUBP = PGA (=27) RUBISCO #12;2/25/2009 4

Miami, University of

403

Evidence of reactive oxygen species-mediated damage to mitochondrial DNA in children with typical autism  

E-Print Network [OSTI]

1997:77–102. 3. Lin MT, Beal MF: Mitochondrial dysfunction13:262–270. 5. Albers DS, Beal MF: Mitochondrial dysfunctionAMS, Mecocci P, Cormio A, Beal MF, Cherubini A, Cantatore P,

Napoli, Eleonora; Wong, Sarah; Giulivi, Cecilia

2013-01-01T23:59:59.000Z

404

Method of enhancing selective isotope desorption from metals  

DOE Patents [OSTI]

A method of enhancing the thermal desorption of a first isotope of a diatomic gas from a metal comprises the steps of (a) establishing a partial pressure of a second isotope of the diatomic gas in vicinity of the metal; heating the metal to a temperature such that the first isotope is desorbed from the metal; and reducing the partial pressure of the desorbed first isotope while maintaining the partial pressure of the second isotope substantially constant. The method is especially useful for enhancing the desorption of tritium from the Zr-Al getter in a plasma confinement device.

Knize, Randall J. (Plainsboro, NJ); Cecchi, Joseph L. (Lawrenceville, NJ)

1984-01-01T23:59:59.000Z

405

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

406

Oxygen addition to sulfur of metal thiolates  

E-Print Network [OSTI]

, and characterized. Molecular oxygen or hydrogen peroxide reacted with (N,N'-bis(mercaptoethyl)-1,5-diazacyclooctane-nickel(II), (BME-DACO)2Ni3 +2, to produce a trimetallic, (N,N'-bismercaptoethyl-1,5-diazacyclooctane-nickel(II))-nickelate, (BME-DACO)2Ni3 2...

Soma, Takako

2012-06-07T23:59:59.000Z

407

Method of preparing mercury with an arbitrary isotopic distribution  

DOE Patents [OSTI]

This invention provides for a process for preparing mercury with a predetermined, arbitrary, isotopic distribution. In one embodiment, different isotopic types of Hg[sub 2]Cl[sub 2], corresponding to the predetermined isotopic distribution of Hg desired, are placed in an electrolyte solution of HCl and H[sub 2]O. The resulting mercurous ions are then electrolytically plated onto a cathode wire producing mercury containing the predetermined isotopic distribution. In a similar fashion, Hg with a predetermined isotopic distribution is obtained from different isotopic types of HgO. In this embodiment, the HgO is dissolved in an electrolytic solution of glacial acetic acid and H[sub 2]O. The isotopic specific Hg is then electrolytically plated onto a cathode and then recovered. 1 fig.

Grossman, M.W.; George, W.A.

1986-12-16T23:59:59.000Z

408

Method of preparing mercury with an arbitrary isotopic distribution  

DOE Patents [OSTI]

This invention provides for a process for preparing mercury with a predetermined, arbitrary, isotopic distribution. In one embodiment, different isotopic types of Hg.sub.2 Cl.sub.2, corresponding to the predetermined isotopic distribution of Hg desired, are placed in an electrolyte solution of HCl and H.sub.2 O. The resulting mercurous ions are then electrolytically plated onto a cathode wire producing mercury containing the predetermined isotopic distribution. In a similar fashion, Hg with a predetermined isotopic distribution is obtained from different isotopic types of HgO. In this embodiment, the HgO is dissolved in an electrolytic solution of glacial acetic acid and H.sub.2 O. The isotopic specific Hg is then electrolytically plated onto a cathode and then recovered.

Grossman, Mark W. (Belmont, MA); George, William A. (Rockport, MA)

1986-01-01T23:59:59.000Z

409

Oxygen-producing inert anodes for SOM process  

DOE Patents [OSTI]

An electrolysis system for generating a metal and molecular oxygen includes a container for receiving a metal oxide containing a metallic species to be extracted, a cathode positioned to contact a metal oxide housed within the container; an oxygen-ion-conducting membrane positioned to contact a metal oxide housed within the container; an anode in contact with the oxygen-ion-conducting membrane and spaced apart from a metal oxide housed within the container, said anode selected from the group consisting of liquid metal silver, oxygen stable electronic oxides, oxygen stable crucible cermets, and stabilized zirconia composites with oxygen stable electronic oxides.

Pal, Uday B

2014-02-25T23:59:59.000Z

410

Stable carbon isotope ratio of polycyclic aromatic hydrocarbons (PAHs) in the environment: validation of isolation and stable carbon isotope analysis methods  

E-Print Network [OSTI]

, purification and compound specific isotope analysis methods were developed to accurately measure the stable carbon isotope ratio of individual PAHs. Development of the method included improving accuracy and precision of the isotopic measurement by producing...

Kim, Moon Koo

2004-11-15T23:59:59.000Z

411

Nucleosynthetic osmium isotope anomalies in acid leachates of the Murchison meteorite  

E-Print Network [OSTI]

We present osmium isotopic results obtained by sequential leaching of the Murchison meteorite, which reveal the existence of very large internal anomalies of nucleosynthetic origin. The Os isotopic anomalies are correlated, and can be explained by the variable contributions of components derived from the s, r and p-processes of nucleosynthesis. Much of the s-process rich osmium is released by relatively mild leaching, suggesting the existence of an easily leachable s-process rich presolar phase, or alternatively, of a chemically resistant r-process rich phase. The s-process composition of Os released by mild leaching diverges slightly from that released by aggressive digestion techniques, perhaps suggesting that the presolar phases attacked by these differing procedures condensed in different stellar environments. The correlation between 190Os and 188Os can be used to constrain the s-process 190Os/188Os ratio to be 1.275 pm 0.043. Such a ratio can be reproduced in a nuclear reaction network for a MACS value for 190Os of ~200 pm 22 mbarn at 30 keV. We also present evidence for extensive internal variation of 184Os abundances in the Murchison meteorite. This suggests that p process rich presolar grains (e.g., supernova condensates) may be present in meteorites in sufficient quantities to influence the Os isotopic compositions of the leachates.

L. Reisberg; N. Dauphas; A. Luguet; D. G. Pearson; R. Gallino; C. Zimmermann

2008-12-15T23:59:59.000Z

412

Removal site evaluation report for the Isotope Facilities at Oak Ridge National Laboratory, Oak Ridge, Tennessee  

SciTech Connect (OSTI)

This removal site evaluation (RmSE) report of the Isotope Facilities at Oak Ridge National Laboratory (ORNL) was prepared to provide the Environmental Restoration Program with information necessary to evaluate whether hazardous and/or radiological contaminants in and around the Isotopes Facility pose a substantial risk to human health or the environment and if remedial site evaluations (RSEs) or removal actions are required. The scope of the project included: (1) a review of historical evidence regarding operations and use of the facility; (2) interviews with facility personnel concerning current and past operating practices; (3) a site inspection; and (4) identification of hazard areas requiring maintenance, removal, or remedial actions. The results of RmSE indicate that no substantial risks exist from contaminants present in the Isotope Facilities because adequate controls and practices exist to protect human health and the environment. The recommended correction from the RmSE are being conducted as maintenance actions; accordingly, this RmSE is considered complete and terminated.

NONE

1996-07-01T23:59:59.000Z

413

The Economics of Oxygen Enriched Air Production Via Membranes  

E-Print Network [OSTI]

Oxygen enriched air combustion is a recognized approach to energy conservation. Conventional methods of producing oxygen enriched air: Pressure Swing Adsorption and Cryogenics, are energy-intensive and expensive. In this paper the economics of using...

Gollan, A.; Kleper, M. H.

1984-01-01T23:59:59.000Z

414

Breath is a mixture of nitrogen, oxygen, carbon dioxide, water  

E-Print Network [OSTI]

12 SCIENCE Breath is a mixture of nitrogen, oxygen, carbon dioxide, water vapour, inert gases. On the basis of proton affinity, the major constituents of air and breath (nitrogen, oxygen, carbon dioxide

415

OXYGEN TRANSFER IN TRICKLING FILTERS By BruceE. Logan~  

E-Print Network [OSTI]

OXYGEN TRANSFER IN TRICKLING FILTERS By BruceE. Logan~ ABSTRACT: Insufficientoxygen transfer can result in anaerobic biofilmsand odor generation during biochemicaloxygen demand (BOD) removal plastic media trickling filters occurs by diffusion of oxygen through thin fluid films, previous models

416

Design, measurement, and analysis of oxygenated fluid pump system  

E-Print Network [OSTI]

The author sought out the opportunity to design and implement a system for pumping oxygenated fluid and mixing it with saline, for the purpose of providing sufficient levels of oxygen for patients undergoing forms of ...

Mason, Alexander M., IV (Alexander Martin)

2012-01-01T23:59:59.000Z

417

Label-free oxygen-metabolic photoacoustic microscopy in vivo  

E-Print Network [OSTI]

tomography (PET) using radioactively labeled oxy- gen. Many other pathological and physiological functions of oxygen consumption instead of the static oxygen concentration.11 If the region of interest has well

Wang, Lihong

418

Optimization of Oxygen Purity for Coal Conversion Energy Reduction  

E-Print Network [OSTI]

The conversion of coal into gaseous and liquid fuels and chemical feedstock will require large quantities of oxygen. This oxygen will be produced in large multi-train air separation plants which will consume about 350 kilowatt hours of energy...

Baker, C. R.; Pike, R. A.

1982-01-01T23:59:59.000Z

419

Optical Perfusion and Oxygenation Characterization in a Liver Phantom  

E-Print Network [OSTI]

Continuous monitoring of blood perfusion and oxygenation is essential in assessing the health of a transplanted organ. Particularly, monitoring the perfusion and oxygenation of the organ during the two-week period after the transplant procedure...

King, Travis J.

2012-02-14T23:59:59.000Z

420

Methane Adsorption and Dissociation and Oxygen Adsorption and...  

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

Methane Adsorption and Dissociation and Oxygen Adsorption and Reaction with CO on Pd Nanoparticles on MgO(100) and on Pd(111). Methane Adsorption and Dissociation and Oxygen...

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

Inhibitive Influence of Oxygen Vacancies for Photoactivity on...  

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

Inhibitive Influence of Oxygen Vacancies for Photoactivity on TiO2(110). Inhibitive Influence of Oxygen Vacancies for Photoactivity on TiO2(110). Abstract: Scanning tunneling...

422

Oxygen-induced magnetic properties and metallic behavior of a...  

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

Oxygen-induced magnetic properties and metallic behavior of a BN sheet. Oxygen-induced magnetic properties and metallic behavior of a BN sheet. Abstract: In this paper, ab initio...

423

Nanoscale Phase Separation, Cation Ordering, and Surface Oxygen...  

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

Separation, Cation Ordering, and Surface Oxygen Chemistry in Pristine Li1.2Ni0.2Mn0.6O2 for Li-Ion Batteries. Nanoscale Phase Separation, Cation Ordering, and Surface Oxygen...

424

On the reduction of oxygen from dispersed media  

E-Print Network [OSTI]

The reduction of oxygen from an organic phase dispersed in a concentrated electrolyte is investigated. Dispersed organic phases are used to enhance oxygen transport in fermenters and artificial blood substitutes. This work ...

Roushdy, Omar H., 1977-

2007-01-01T23:59:59.000Z

425

Ambient dissolved oxygen concentrations in Delaware's Inland Bays. Final report, June 6, 1984  

SciTech Connect (OSTI)

Ambient dissolved oxygen concentrations were measured at dawn during August, 1983, in Rehoboth and Indian River Bays. In Indian River Bay, 59% of the D.O. measurements were below the State minimum water quality standard of 5 mg L/sup -1/, while in Rehoboth Bay 17% of the values fail to meet the State standards. Diurnal dissolved oxygen curves measured at 5 stations in the Bays and tributary creeks, provide evidence that, although the Bays are in reasonable balance with respect to apparent net daytime photosynthesis (Pa) and nighttime respiration (Rn), the absolute values of Pa and Rn are very high, compared with other coastal ecosystems, except for central Rehoboth Bay. These conclusions are consistent with the annual nutrient loads to the systems, which are about double for Indian River when contrasted with Rehoboth. 11 references, 1 figure, 7 tables.

Biggs, R.B.

1984-01-01T23:59:59.000Z

426

Rates and products of degradation for MTBE and other oxygenate fuel additives in the subsurface environment  

SciTech Connect (OSTI)

The recent realization that oxygenated fuel additives such as MTBE are becoming widely distributed groundwater contaminants has created a sudden and pressing demand for data on the processes that control their environmental fate. Explaining and predicting the subsequent environmental fate of these compounds is going to require extrapolations over long time frames that will be very sensitive to the quality of input data on each compound. To provide such data, they have initiated a systematic study of the pathways and kinetics of fuel oxygenate degradation under subsurface conditions. Batch experiments in simplified model systems are being performed to isolate specific processes that may contribute to MTBE degradation. A variety of degradation pathways can be envisioned that lead to t-butyl alcohol (TBA) as the primary or secondary product. However, experiments to date with a facultative iron reducing bacteria showed no evidence for TBA formation. Continuing experiments include mixed cultures from a range of aquifer materials representative of NAWQA study sites.

Tratnyek, P.G.; Church, C.D.; Pankow, J.F. [Oregon Graduate Inst., Portland, OR (United States). Dept. of Environmental Science and Engineering

1995-12-31T23:59:59.000Z

427

Inorganic origin of carbon dioxide during low temperature thermal recovery of bitumen: Chemical and isotopic evidence  

SciTech Connect (OSTI)

Carbon dioxide, produced at low temperatures, is the dominant gaseous species evolved during steam-assisted thermal recovery of bitumen at the Tucker Lake pilot, Cold Lake, Alberta. Two possible sources for the produced CO{sub 2} are considered: pyrolysis of bitumen and dissolution of carbonate minerals. Data from natural systems and experiments by other authors suggest that clay-carbonate reactions are the dominant source of CO{sub 2}. Bitumen pyrolysis may contribute small amounts of CO{sub 2}, probably by decarboxylation, early in the production cycle but cannot contribute significant volumes. The recognition of production of CO{sub 2} by reactive calcite destruction at temperatures between 70 and 220{degree}C suggests that this process may be responsible for the production of large quantities of CO{sub 2} in natural systems, particularly in lithofeldspathic sands and shales with high carbonate content and abundant clays. Organic acids have been suggested to be the source of CO{sub 2} in diagenetic fluids, but the results presented here suggest that this hypothesis requires more complete investigation.

Hutcheon, I.; Abercrombia, H.J.; Krouse, H.R. (Univ. of Calgary, Alberta (Canada))

1990-01-01T23:59:59.000Z

428

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

E-Print Network [OSTI]

. 7 249. 2 ? 254. 2 1. 9 502. 5 498. 9 ? 506. 1 Calculation of Tracer Uptake/Loss by Plants The daily percent dose transpired values were calculated according to the following steps: 1. ) ppm excess = ppm postdose ? ppm background where ppm... tissue of annual broomweed (Fig. 7). Consequently, there was also a strong correlation between the calculated values of the daily percent dose transpired for all sample periods (Table 3). Analysis of variance (e = . 05) indicated that the daily...

Yoder, Carolyn Kay

1993-01-01T23:59:59.000Z

429

Diffusional exchange of isotopes in a metal hydride sphere.  

SciTech Connect (OSTI)

This report describes the Spherical Particle Exchange Model (SPEM), which simulates exchange of one hydrogen isotope by another hydrogen isotope in a spherical metal hydride particle. This is one of the fundamental physical processes during isotope exchange in a bed of spherical metal particles and is thus one of the key components in any comprehensive physics-based model of exchange. There are two important physical processes in the model. One is the entropy of mixing between the two isotopes; the entropy of mixing is increased by having both isotopes randomly placed at interstitial sites on the lattice and thus impedes the exchange process. The other physical process is the elastic interaction between isotope atoms on the lattice. The elastic interaction is the cause for {beta}-phase formation and is independent of the isotope species. In this report the coupled diffusion equations for two isotopes in the {beta}-phase hydride are solved. A key concept is that the diffusion of one isotope depends not only on its concentration gradient, but also on the concentration gradient of the other isotope. Diffusion rate constants and the chemical potentials for deuterium and hydrogen in the {beta}-phase hydride are reviewed because these quantities are essential for an accurate model of the diffusion process. Finally, a summary of some of the predictions from the SPEM model are provided.

Wolfer, Wilhelm G.; Hamilton, John C.; James, Scott Carlton

2011-04-01T23:59:59.000Z

430

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

This quarterly technical progress report will summarize work accomplished for the Program through the second quarter July--September 2000 in the following task areas: Task 1-Oxygen Enhanced Combustion, Task 2-Oxygen Transport Membranes and Task 4-Program Management. The program is proceeding in accordance with the objectives for the first year. OTM tube characterization is well underway, the design and assembly of the high pressure permeation test facility is complete and the facility will be in full operation during the next quarter. Combustion testing has been initiated at both the University of Arizona and Praxair. Testing at the University of Arizona has experienced some delays; steps have been take to get the test work back on schedule. Completion of the first phase of the testing is expected in next quarter. Combustion modeling has been started at both REI and Praxair, preliminary results are expected in the next quarter.

Lawrence E. Bool; Jack C. Chen; David R. Thompson

2000-10-01T23:59:59.000Z

431

Electrical insulator assembly with oxygen permeation barrier  

DOE Patents [OSTI]

A high-voltage electrical insulator for electrically insulating a thermoelectric module in a spacecraft from a niobium-1% zirconium alloy wall of a heat exchanger filled with liquid lithium while providing good thermal conductivity between the heat exchanger and the thermoelectric module. The insulator has a single crystal alumina layer (SxAl[sub 2]O[sub 3], sapphire) with a niobium foil layer bonded thereto on the surface of the alumina crystal facing the heat exchanger wall, and a molybdenum layer bonded to the niobium layer to act as an oxygen permeation barrier to preclude the oxygen depleting effects of the lithium from causing undesirable niobium-aluminum intermetallic layers near the alumina-niobium interface. 3 figures.

Van Der Beck, R.R.; Bond, J.A.

1994-03-29T23:59:59.000Z

432

Isotopic noble gas signatures released from medical isotope production facilities - Simulations and measurements  

SciTech Connect (OSTI)

Journal article on the role that radioxenon isotopes play in confirming whether or not an underground explosion was nuclear in nature. Radioxenon isotopes play a major role in confirming whether or not an underground explosion was nuclear in nature. It is then of key importance to understand the sources of environmental radioxenon to be able to distinguish civil sources from those of a nuclear explosion. Based on several years of measurements, combined with advanced atmospheric transport model results, it was recently shown that the main source of radioxenon observations are strong and regular batch releases from a very limited number of medical isotope production facilities. This paper reviews production processes in different medical isotope facilities during which radioxenon is produced. Radioxenon activity concentrations and isotopic compositions are calculated for six large facilities. The results are compared with calculated signals from nuclear explosions. Further, the outcome is compared and found to be consistent with radioxenon measurements recently performed in and around three of these facilities. Some anomalies in measurements in which {sup 131m}Xe was detected were found and a possible explanation is proposed. It was also calculated that the dose rate of the releases is well below regulatory values. Based on these results, it should be possible to better understand, interpret and verify signals measured in the noble gas measurement systems in the International Monitoring of the Comprehensive Nuclear-Test-Ban Treaty.

Saey, Paul R.; Bowyer, Ted W.; Ringbom, Anders

2010-09-09T23:59:59.000Z

433

High Flux Isotope Reactor power upgrade status  

SciTech Connect (OSTI)

A return to 100-MW operation is being planned for the High Flux Isotope Reactor (HFIR). Recent improvements in fuel element manufacturing procedures and inspection equipment will be exploited to reduce hot spot and hot streak factors sufficiently to permit the power upgrade without an increase in primary coolant pressure. Fresh fuel elements already fabricated for future use are being evaluated individually for power upgrade potential based on their measured coolant channel dimensions.

Rothrock, R.B.; Hale, R.E. [Oak Ridge National Lab., TN (United States); Cheverton, R.D. [Delta-21 Resources Inc., Oak Ridge, TN (United States)

1997-03-01T23:59:59.000Z

434

Concerning the Facility for Rare Isotope Beams  

ScienceCinema (OSTI)

James Symons, Nuclear Science Division Director at Lawrence Berkeley Lab, and Daniela Leitner, head of operations at Berkeley Lab's 88-Inch Cyclotron, discuss major contributions to the new Facility for Rare Isotope Beams (FRIB) at Michigan State University, including ion source, which will based on the VENUS source built for the 88-Inch Cyclotron, and the GRETA gamma-ray detector now under construction there.

Symons, James

2013-05-29T23:59:59.000Z

435

Optically pumped isotopic ammonia laser system  

DOE Patents [OSTI]

An optically pumped isotopic ammonia laser system which is capable of producing a plurality of frequencies in the middle infrared spectral region. Two optical pumping mechanisms are disclosed, i.e., pumping on R(J) and lasing on P(J) in response to enhancement of rotational cascade lasing including stimulated Raman effects, and, pumping on R(J) and lasing on P(J+2). The disclosed apparatus for optical pumping include a hole coupled cavity and a grating coupled cavity.

Buchwald, Melvin I. (Santa Fe, NM); Jones, Claude R. (Los Alamos, NM); Nelson, Leonard Y. (Seattle, WA)

1982-01-01T23:59:59.000Z

436

A miniature inexpensive, oxygen sensing element  

SciTech Connect (OSTI)

An exhaustive study was conducted to determine the feasibility of Nernst-type oxygen sensors based on ceramics containing Bi{sub 2}O{sub 3}. The basic sensor design consisted of a ceramic sensing module sealed into a metal tube. The module accommodated an internal heater and thermocouple. Thermal-expansion-matched metals, adhesives, and seals were researched and developed, consistent with sequential firings during sensor assembly. Significant effort was devoted to heater design/testing and to materials' compatibility with Pt electrodes. A systematic approach was taken to develop all sensor components which led to several design modifications. Prototype sensors were constructed and exhaustively tested. It is concluded that development of Nerst-type oxygen sensors based on Bi{sub 2}O{sub 3} will require much further effort and application of specialized technologies. However, during the course of this 3-year program much progress was reported in the literature on amperometric-type oxygen sensors, and a minor effort was devoted here to this type of sensor based on Bi{sub 2}O{sub 3}. These studies were made on Bi{sub 2}O{sub 3}-based ceramic samples in a multilayer-capacitor-type geometry and amperometric-type oxygen sensing was demonstrated at very low temperatures ({approximately} 160{degree}C). A central advantage here is that these types of sensors can be mass-produced very inexpensively ({approximately} 20--50 cents per unit). Research is needed, however, to develop an optimum diffusion-limiting barrier coating. In summary, the original goals of this program were not achieved due to unforeseen problems with Bi{sub 2}O{sub 3}-based Nernst sensors. However, a miniature amperometric sensor base on Bi{sub 2}O{sub 3} was demonstrated in this program, and it is now seen that this latter sensor is far superior to the originally proposed Nernst sensor. 6 refs., 24 figs.

Arenz, R.W.

1991-10-07T23:59:59.000Z

437

Oxygen stabilized zirconium vanadium intermetallic compound  

DOE Patents [OSTI]

An oxygen stabilized intermetallic compound having the formula Zr.sub.x OV.sub.y where x=0.7 to 2.0 and y=0.18 to 0.33. The compound is capable of reversibly sorbing hydrogen at temperatures from -196.degree. C. to 450.degree. C. at pressures down to 10.sup.-6 Torr. The compound is also capable of selectively sorbing hydrogen from gaseous mixtures in the presence of CO and CO.sub.2.

Mendelsohn, Marshall H. (Woodridge, IL); Gruen, Dieter M. (Downers Grove, IL)

1982-01-01T23:59:59.000Z

438

Hydrogen isotope separation utilizing bulk getters  

DOE Patents [OSTI]

Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

Knize, Randall J. (Los Angeles, CA); Cecchi, Joseph L. (Lawrenceville, NJ)

1991-01-01T23:59:59.000Z

439

Hydrogen isotope separation utilizing bulk getters  

DOE Patents [OSTI]

Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

Knize, Randall J. (Los Angeles, CA); Cecchi, Joseph L. (Lawrenceville, NJ)

1990-01-01T23:59:59.000Z

440

Hydrogen isotope separation utilizing bulk getters  

DOE Patents [OSTI]

Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen. 4 figures.

Knize, R.J.; Cecchi, J.L.

1991-08-20T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL  

SciTech Connect (OSTI)

This quarterly technical progress report will summarize work accomplished for the Program through the ninth quarter April-June 2002 in the following task areas: Task 1--Oxygen Enhanced Combustion, Task 2--Oxygen Transport Membranes, Task 3--Economic Evaluation and Task 4--Program Management. The program is proceeding in accordance with the objectives for the third year. Full-scale testing using the Industrial Boiler Simulation Facility (ISBF) at Alstom Power was completed. The pilot scale experiments to evaluate the effect of air preheat and transport air stoichiometric ratio (SR) on NOx emissions were conducted at the University of Utah. Combustion modeling activities continued with full-scale combustion test furnace simulations. An OTM element was tested in Praxair's single tube high-pressure test facility and two thermal cycles were completed. PSO1d elements of new dimension were tested resulting in a lower flux than previous PSO1d elements of different dimensions, however, no element deformation was observed. Economic evaluation has confirmed the advantage of oxygen-enhanced combustion. Two potential host beta sites have been identified and proposals submitted.

David R. Thompson; Lawrence E. Bool; Jack C. Chen

2002-08-01T23:59:59.000Z

442

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

443

Quasi-Reversible Oxygen Exchange of Amorphous IGZO Thin Films  

E-Print Network [OSTI]

MRSEC Quasi-Reversible Oxygen Exchange of Amorphous IGZO Thin Films NSF Grant # 1121262 A. U. Adler of varying oxygen partial pressure. Oxygen exchange was confirmed by 18O tracer diffusion (time of carrier content vs. pO2) analysis should be applicable for studying the underlying carrier generation

Shahriar, Selim

444

Oxygen Reduction DOI: 10.1002/anie.201403264  

E-Print Network [OSTI]

Oxygen Reduction DOI: 10.1002/anie.201403264 Dramatic Increase in the Oxygen Reduction Reaction solvation) is used to predict how the energies and barriers for the mechanistic steps of the oxygen. In these electro- chemical devices, H2 (generated e.g. from solar energy conversion) reacts with O2 to produce

Goddard III, William A.

445

IMPROVEMENTS IN MODELLING DISSOLVED OXYGEN IN ACTIVATED SLUDGE SYSTEMS  

E-Print Network [OSTI]

1 IMPROVEMENTS IN MODELLING DISSOLVED OXYGEN IN ACTIVATED SLUDGE SYSTEMS Jacek Makinia*, Scott A in a full-scale activated sludge reactor. The Activated Sludge Model No. 1 was used to describe for dissolved oxygen. KEYWORDS Activated sludge; dispersion; dissolved oxygen dynamics; mass transfer

Wells, Scott A.

446

Oceanic oxygen changes as a bellwether of climate change  

E-Print Network [OSTI]

Oceanic oxygen changes as a bellwether of climate change Term paper in Biogeochemistry@ethz.ch] Tutor: Prof. Dr. Nicholas Gruber [nicholas.gruber@env.ethz.ch] Abstract The response of oceanic oxygen of climate change. Recent publications indicate that the oceanic oxygen outgassing is substaintially larger

Fischlin, Andreas

447

Fiber-optic oxygen sensor using molybdenum chloride cluster luminescence  

E-Print Network [OSTI]

Fiber-optic oxygen sensor using molybdenum chloride cluster luminescence Ruby N. Ghosh,a) Gregory L on a reflection-mode fiber-optic oxygen sensor based on the 3 O2 quenching of the red emission from hexanuclear molybdenum chloride clusters. Measurements of the probe operating in a 0%­21% gaseous oxygen environment have

Ghosh, Ruby N.

448

THE OXYGEN REQUIREMENTS OF SHELLFISH By Philip H. Mitchell  

E-Print Network [OSTI]

THE OXYGEN REQUIREMENTS OF SHELLFISH ~ By Philip H. Mitchell 2°7 #12;Blank page retained for pagination #12;THE OXYGEN REQUIREMENTS OF SHELLFISH. By PHILIP H. MITCHELL. J1, The respiratory exchanges to temperature changes, a smaller utili- zation of oxygen in proportion to the body weight with increase in size

449

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...

450

Green fluorescent protein based indicators of dynamic redox changes and reactive oxygen species  

E-Print Network [OSTI]

attached a singlet oxygen generator to the C-terminal ofencoded singlet oxygen generators, which is currentlyassays. A. Singlet oxygen generator and sensor are tethered;

Dooley, Colette

2006-01-01T23:59:59.000Z

451

E-Print Network 3.0 - acute oxygen sensing Sample Search Results  

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

dissolved oxygen with global warming. In coastal regimes oxygen deficits represent acute ecosystem... Ocean oxygen minima expansions and their biological impacts Lothar Stramma...

452

Oxygen-driven relaxation processes in pre-irradiated Ar cryocrystals  

E-Print Network [OSTI]

Excitations of Solid Oxygen ?in Russian?, B. I. Verkin andNUMBER 11 NOVEMBER 2006 Oxygen-driven relaxation processes? Relaxation processes in oxygen-containing Ar cryocrystals

Savchenko, E. V; Belov, A. G; Gumenchuk, G. B; Ponomaryov, A. N; Bondybey, V. E

2006-01-01T23:59:59.000Z

453

OXYGEN REDUCTION WITH CARBON SUPPORTED METALLIC CLUSTER CATALYSTS IN ALKALINE ELECTROLYTE  

E-Print Network [OSTI]

be published in the Proceedings OXYGEN REDUCTION WITH CARBONof California. LBL-11891 Oxygen Reduction with Carbonof Pt interacts with both oxygen and water more strongly

Ross Jr., Philip N.

2013-01-01T23:59:59.000Z

454

E-Print Network 3.0 - active oxygen control Sample Search Results  

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

Powered by Explorit Topic List Advanced Search Sample search results for: active oxygen control Page: << < 1 2 3 4 5 > >> 1 Oxygen Modulation via Microfluidic Devices Oxygen...

455

Magnesium isotopic systematics of chondrules and CAIs from Allende, Murchison, Murray and Bjurbole. F.-, M. Wadhwa1,  

E-Print Network [OSTI]

Magnesium isotopic systematics of chondrules and CAIs from Allende, Murchison, Murray and Bjurbole: Magnesium isotopic analyses were performed at the Isotope Geochemistry Labora- tory of the Field Museum

Grossman, Lawrence

456

Stable isotopes composition of precipitation fallen over Cluj-Napoca, Romania, between 2009-2012  

SciTech Connect (OSTI)

The paper presents the deuterium and oxygen 18 content from All precipitations events, which have occured over Cluj-Napoca, Romania from 2009 until 2012. Time series for ?{sup 2}H and ?{sup 18}O values point out both the seasonal variation that has increased amplitude reflecting the continental character of the local climate as well as dramatic variations of isotopic content of successive precipitation events, emphasizing the anomalous values. These fluctuations are the footprint of the variations and trends in climate events. Local Meteoric Water Line (LMWL), reflecting the ?{sup 2}H - ?{sup 18}O correlation, has the slop and the intercept slightly deviated from the GMWL, indicating that the dominant process affecting local precipitations are close to the equilibrium condition. LMWL has a slope smaller then that of the GMWL in the warm season due to lower humidity and a slope closest to the slop of GMWL in cold season with high humidity. The ?{sup 2}H and ?{sup 18}O values both for the precipitation events and monthly mean values are positively correlated with the temperature values with a very good correlation factor. The values of ?{sup 2}H and ?{sup 18}O are not correlated with amount of precipitation, the 'amount effect' of isotopic composition of precipitation is not observed for this site.

Puscas, R.; Feurdean, V. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania)] [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania); Simon, V. [Babes-Bolyai University Faculty of Physics (Romania)] [Babes-Bolyai University Faculty of Physics (Romania)

2013-11-13T23:59:59.000Z

457

Dilute Oxygen Combustion Phase IV Final Report  

SciTech Connect (OSTI)

Novel furnace designs based on Dilute Oxygen Combustion (DOC) technology were developed under subcontract by Techint Technologies, Coraopolis, PA, to fully exploit the energy and environmental capabilities of DOC technology and to provide a competitive offering for new furnace construction opportunities. Capital cost, fuel, oxygen and utility costs, NOx emissions, oxide scaling performance, and maintenance requirements were compared for five DOC-based designs and three conventional air5-fired designs using a 10-year net present value calculation. A furnace direct completely with DOC burners offers low capital cost, low fuel rate, and minimal NOx emissions. However, these benefits do not offset the cost of oxygen and a full DOC-fired furnace is projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The incremental cost of the improved NOx performance is roughly $6/lb NOx, compared with an estimated $3/lb. NOx for equ8pping a conventional furnace with selective catalytic reduction (SCCR) technology. A furnace fired with DOC burners in the heating zone and ambient temperature (cold) air-fired burners in the soak zone offers low capital cost with less oxygen consumption. However, the improvement in fuel rate is not as great as the full DOC-fired design, and the DOC-cold soak design is also projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The NOx improvement with the DOC-cold soak design is also not as great as the full DOC fired design, and the incremental cost of the improved NOx performance is nearly $9/lb NOx. These results indicate that a DOC-based furnace design will not be generally competitive with conventional technology for new furnace construction under current market conditions. Fuel prices of $7/MMBtu or oxygen prices of $23/ton are needed to make the DOC furnace economics favorable. Niche applications may exist, particularly where access to capital is limited or floor space limitations are critical. DOC technology will continue to have a highly competitive role in retrofit applications requiring increases in furnace productivity.

Riley, M.F.

2003-04-30T23:59:59.000Z

458

Oxygen enrichment in carbon-rich planetary nebulae  

E-Print Network [OSTI]

We study the relation between the chemical composition and the type of dust present in a group of 20 Galactic planetary nebulae (PNe) that have high quality optical and infrared spectra. The optical spectra are used, together with the best available ionization correction factors, to calculate the abundances of Ar, C, Cl, He, N, Ne, and O relative to H. The infrared spectra are used to classify the PNe in two groups depending on whether the observed dust features are representative of oxygen-rich or carbon-rich environments. The sample contains one object from the halo, eight from the bulge, and eleven from the local disc. We compare their chemical abundances with nucleosynthesis model predictions and with the ones obtained in seven Galactic H II regions of the solar neighbourhood. We find evidence of O enrichment (by $\\sim$ 0.3 dex) in all but one of the PNe with carbon-rich dust (CRD). Our analysis shows that Ar, and especially Cl, are the best metallicity indicators of the progenitors of PNe. There is a tig...

Delgado-Inglada, Gloria; Peimbert, Manuel; Stasi?ska, Gra?yna; Morisset, Christophe

2015-01-01T23:59:59.000Z

459

Magnetic interaction in oxygenated alpha Fe-phthalocyanines  

SciTech Connect (OSTI)

Alpha iron phthalocyanines (?-FePc) oxygenated at low temperatures were investigated with the help of {sup 57}Fe Mössbauer spectroscopy, magnetization measurements (SQUID) and X-ray diffractometry (XRD). Mössbauer spectroscopy revealed that upon oxygenation of ?-FePc, new species were formed which could be associated with Fe{sup III}Pc oxygen adducts. Unexpectedly, magnetically split spectrum of oxygenated ?-FePc was observed below 20 K. In-field Mössbauer spectra in a 5 T external magnetic field at 5K and magnetization measurements indicate antiferromagnetic coupling in oxygenated ?-FePc.

Kuzmann, Ern?, E-mail: kuzmann@caesar.elte.hu; Homonnay, Zoltán; Horváth, Attila [Institute of Chemistry, Eötvös Loránd University, P.O. Box 32, 1512 Budapest (Hungary); Pechousek, Jiri; Cuda, Jan; Machala, Libor; Zoppellaro, Giorgio; Zboril, Radek [Regional Centre of Advanced Technologies and Materials, Departments of Experimental Physics and Physical Chemistry, Faculty of Science Palacky University, 17. Listopadu 1192/12, 771 46 Olomouc (Czech Republic); Yin, Houping; Wei, Yen [Department of Chemistry, Drexel University, Philadelphia, PA 19104 (United States); Klencsár, Zoltán [Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, 1117 (Hungary); Kubuki, Shiro [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachi-Oji, Tokyo 192-0397 (Japan); Nath, Amar [Department of Chemistry, University of North Carolina, Asheville, NC 28804 (United States)

2014-10-27T23:59:59.000Z

460

System and method for high precision isotope ratio destructive analysis  

DOE Patents [OSTI]

A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

2013-07-02T23:59:59.000Z

Note: This page contains sample records for the topic "oxygen isotope evidence" 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

A Strontium Isotopic Study Of Newberry Volcano, Central Oregon...  

Open Energy Info (EERE)

Strontium Isotopic Study Of Newberry Volcano, Central Oregon- Structural And Thermal Implications Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal...

462

Isotopic Analysis- Fluid At Long Valley Caldera Geothermal Area...  

Open Energy Info (EERE)

Farrar, Et Al., 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Long Valley Caldera Geothermal Area (Farrar, Et...

463

Isotope and Temperature Effects in Liquid Water Probed by Soft...  

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

of temperature and isotope substitution (replacing the hydrogen with deuterium to make "heavy" water). Their findings shed new light on the unique microscopic and macroscopic...

464

Chemical And Isotopic Investigation Of Warm Springs Associated...  

Open Energy Info (EERE)

water (high TDS, > 5000 mgl). Deviations from the meteoric water line are the result of rock-water isotopic exchange, mixing or evaporation. Fluid source regions and residence...

465

Geochemistry and Isotopes of Fluids from Sulphur Springs, Valles...  

Open Energy Info (EERE)

and Isotopes of Fluids from Sulphur Springs, Valles Caldera, New Mexico Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Geochemistry and...

466

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

Open Energy Info (EERE)

Jamie N. Gardner, Rosemary Vidale, Robert Charles (1985) Geochemistry and Isotopes of Fluids from Sulphur Springs, Valles Caldera, New Mexico Additional References Retrieved from...

467

Isotopic Analysis- Fluid At Roosevelt Hot Springs Geothermal...  

Open Energy Info (EERE)

of the Roosevelt Hot Springs Geothermal Area. Notes Stable isotope analysis of thermal fluids determined meteoric origin primarily from the Mineral Mountains with a small...

468

A Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal...  

Open Energy Info (EERE)

A Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal System Abstract Fluids from springs, fumaroles, and wells throughout Dixie Valley, NV were analyzed for noble...

469

Isotopic Analysis- Rock At Kilauea East Rift Geothermal Area...  

Open Energy Info (EERE)

Technique Isotopic Analysis- Rock Activity Date 1989 - 2000 Usefulness not indicated DOE-funding Unknown Exploration Basis The purpose of this study was to analyze deep core...

470

Isotopic Analysis- Fluid At Kilauea East Rift Geothermal Area...  

Open Energy Info (EERE)

navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Kilauea East Rift Geothermal Area (Scholl, Et Al., 1993) Exploration...

471

Isotopic Analysis- Fluid At Indian Valley Hot Springs Geothermal...  

Open Energy Info (EERE)

Activity: Isotopic Analysis- Fluid At Indian Valley Hot Springs Geothermal Area (1990) Exploration Activity Details Location Indian Valley Hot Springs Geothermal Area...

472

Isotopic Analysis At Walker-Lane Transitional Zone Region (Kennedy...  

Open Energy Info (EERE)

Zone Region (Kennedy & Van Soest, 2007) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity...

473

Isotopic Analysis At Valles Caldera - Redondo Geothermal Area...  

Open Energy Info (EERE)

White, Et Al., 1992) Exploration Activity Details Location Valles Caldera - Redondo Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date - 1992 Usefulness...

474

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

Open Energy Info (EERE)

Activity: Isotopic Analysis- Fluid At Valles Caldera - Sulphur Springs Geothermal Area (White, Et Al., 1992) Exploration Activity Details Location Valles Caldera - Sulphur Springs...

475

Isotopic Analysis At Valles Caldera - Redondo Geothermal Area...  

Open Energy Info (EERE)

White, 1986) Exploration Activity Details Location Valles Caldera - Redondo Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date - 1986 Usefulness not...

476

Integrated Approach to Use Natural Chemical and Isotopic Tracers...  

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

Integrated Approach to Use Natural Chemical and Isotopic Tracers to Estimate Fracture Spacing and Surface Area in EGS Systems Integrated Approach to Use Natural Chemical and...

477

Integrated Approach to Use Natural Chemical and Isotopic Tracers...  

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

Approach to Use Natural Chemical and Isotopic Tracers to Estimate Fracture Spacing and Surface Area in EGS Systems B. Mack Kennedy (Presenter) and H. H. Liu Lawrence Berkeley...

478

Hydrogeological And Isotopic Survey Of Geothermal Fields In The...  

Open Energy Info (EERE)

Hydrogeological And Isotopic Survey Of Geothermal Fields In The Buyuk Menderes Graben, Turkey Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article:...

479

Workshop on The Nation's Needs for Isotopes: Present and Future...  

Office of Science (SC) Website

Workshop on The Nation's Needs for Isotopes: Present and Future Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Funding Opportunities...

480

Dissolved Oxygen in Allen CreekDissolved Oxygen in Allen Creek Dissolved oxygen (DO) enters the water by diffusion from air, as a by-product of photosynthesis and  

E-Print Network [OSTI]

Dissolved Oxygen in Allen CreekDissolved Oxygen in Allen Creek Dissolved oxygen (DO) enters and rapids. There is an inverse relationship between temperature and DO, i.e. colder water holds more oxygen it supplies oxygen to aquatic organisms. Higher DO levels also give the water a better taste. Figure 2. During

Tyler, Christy

Note: This page contains sample records for the topic "oxygen isotope evidence" 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.


481

FORMATION OF MOLECULAR OXYGEN AND OZONE ON AMORPHOUS SILICATES  

SciTech Connect (OSTI)

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

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

2012-09-01T23:59:59.000Z

482

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

483

Carbon and oxygen stable isotopes in the Toa Baja Well, Puerto Rico: implications for burial diagenesis and hydrocarbon generation  

E-Print Network [OSTI]

that the bulk of the sediment pile has not been exposed to temperatures above the oil window and possibly hydrocarbons have been generated deeper in the basin....

Gonzalez, Luis A.

1991-03-01T23:59:59.000Z

484

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

E-Print Network [OSTI]

utility libraries to which it must be linked after A general description of the program function precedes the program listing.

Creager, W.N.

2009-01-01T23:59:59.000Z

485

The oxygen isotope effect on the polaronic infrared photo-induced absorption spectra of La2CuO4  

E-Print Network [OSTI]

consisting of the two pronounced low-energy (LE) and high- energy (HE) features are observed in the layered the discovery of the high- temperature superconductivity in layered cuprates by Bednorz and Müller a large exchange and in situ during the exchange process using mass spectrometry. This was 84±2 % the rest being

486

Oxygen Isotope Effects on Electron Transfer to O2 Probed Using Chemically Modified Flavins Bound to Glucose Oxidase  

E-Print Network [OSTI]

-reaching consequences, possibly leading to improved biosensors1 and fuel cells2 and to the development of "green2 of ) 28 kcal mol-1 at optimal pH, which is similar to the value obtained earlier from temperature

Roth, Justine P.

487

Comparison of species-specific oxygen isotope paleotemperature equations: Sensitivity analysis using planktonic foraminifera from the Cariaco Basin, Venezuela  

E-Print Network [OSTI]

using planktonic foraminifera from the Cariaco Basin, Venezuela Katherine E. Wejnert a, , Robert C, Venezuela a b s t r a c ta r t i c l e i n f o Article history: Received 6 December 2011 Received in revised biweekly sediment trap samples collected in Cariaco Basin, Venezuela between 2003 and 2008. Sixteen

Meyers, Steven D.

488

Phosphorus cycling in the Sargasso Sea: Investigation using the oxygen isotopic composition of phosphate, enzyme-labeled  

E-Print Network [OSTI]

of the ocean are extremely low (M) and phosphorus (P) availability could limit primary productivity is supported by DOP uptake. Citation: McLaughlin, K., J. A. Sohm, G. A. Cutter, M. W. Lomas, and A. Paytan al., 2006; Lomas et al., 2010; Torres-Valdes et al., 2009]. However, the complex biogeochemical

Paytan, Adina

489

Phosphorus cycling in the Sargasso Sea: Investigation using the oxygen isotopic composition of phosphate, enzyme-labeled  

E-Print Network [OSTI]

of vast areas of the ocean are extremely low (M) and phosphorus (P) availability could limit primary, G. A. Cutter, M. W. Lomas, and A. Paytan (2013), Phosphorus cycling in the Sargasso Sea in the ocean via the biological pump [Dyhrman et al., 2006; Lomas et al., 2010; Torres-Valdes et al., 2009

Paytan, Adina

490

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

E-Print Network [OSTI]

and thence to temperature #1;(Arppe and Karhu, 2010; Navarro et al., 2004; Skrzypek et al., 2011; Tütken et al., 2007). These investigations require two data conversions that are based on well demonstrated correlations: Z1 A species-specific conversion...

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

2014-07-18T23:59:59.000Z

491

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

SciTech Connect (OSTI)

The oxygen reduction/evolution reaction (ORR/OER) mechanisms in nonaqueous Li-O2 batteries have been investigated by using electron paramagnetic resonance spectroscopy in this work. We identified the superoxide radical anion (O2•-) as an intermediate in the ORR process using 5,5-dimethyl-pyrroline N-oxide as a spin trap, while no O2•- in OER was detected during the charge process. These findings provide insightful understanding on the fundamental oxygen reaction mechanisms in rechargeable nonaqueous Li-O2 batteries.

Cao, Ruiguo; Walter, Eric D.; Xu, Wu; Nasybulin, Eduard N.; Bhattacharya, Priyanka; Bowden, Mark E.; Engelhard, Mark H.; Zhang, Jiguang

2014-09-30T23:59:59.000Z

492

How Plants Do It: Light, Oxygen, Action!  

SciTech Connect (OSTI)

Plants have been doing it with ease for millions of years, and yet science has yet to fully comprehend how: Photosynthesis. It's a fundamental process of all plant life on Earth, using the simple and abundant ingredients of water and light to create food and enrich the planet's atmosphere with life-giving oxygen. In this talk, Professor Yachandra discusses how understanding the process of photosynthesis holds the key to a whole new level of mastery of how energy is produced, with enormous implications for the economy and the environment.

Yachandra, Vittal (University of California, Berkeley) [University of California, Berkeley

2008-08-26T23:59:59.000Z

493

SUPPORTED DENSE CERAMIC MEMBRANES FOR OXYGEN SEPARATION  

SciTech Connect (OSTI)

Mixed-conducting membranes have the ability to conduct oxygen with perfect selectivity at elevated temperatures, which makes them an extremely attractive alternative for oxygen separation and membrane reactor applications. The ability to reliably fabricate these membranes in thin or thick films would enable solid-state divisional limitations to be minimized, thus providing higher oxygen flux. Based on that motivation, the overall objective for this project is to develop and demonstrate a strategy for the fabrication of supported Wick film ceramic mixed conducting membranes, and improve the understanding of the fundamental issues associated with reliable fabrication of these membranes. The project has focused on the mixed-conducting ceramic composition SrCo{sub 0.5}FeO{sub x} because of its superior permeability and stability in reducing atmospheres. The fabrication strategy employed involves the deposition of SrCo{sub 0.5}FeO{sub x} thick films onto porous supports of the same composition. In the second year of this project, we completed characterization of the sintering and phase behavior of the porous SrCo{sub 0.5}FeO{sub x} supports, leading to a standard support fabrication methodology. Using a doctor blade method, pastes made from aerosol-derived SrCo{sub 0.5}FeO{sub x} powder dispersed with polyethylene glycol were applied to the supports, and the sintering behavior of the thick film membranes was examined in air and nitrogen atmospheres. It has been demonstrated that the desired crystalline phase content can be produced in the membranes, and that the material in the membrane layer can be highly densified without densifying the underlying support. However, considerable cracking and opening of the film occurred when films densified to a high extent. The addition of MgO into the SrCo{sub 0.5}FeO{sub x} supports was shown to inhibit support sintering so that temperatures up to 1300 C, where significant liquid formation occurs, could be used for film sintering. This successfully reduced cracking, however the films retained open porosity. The investigation of this concept will be continued in the final year of the project. Investigation of a metal organic chemical vapor deposition (MOCVD) method for defect mending in dense membranes was also initiated. An appropriate metal organic precursor (iron tetramethylheptanedionate) was identified whose deposition can be controlled by access to oxygen at temperatures in the 280-300 C range. Initial experiments have deposited iron oxide, but only on the membrane surface; thus refinement of this method will continue.

Timothy L. Ward

2000-06-30T23:59:59.000Z

494

Oxygen stabilized zirconium-vanadium-iron alloy  

DOE Patents [OSTI]

An oxygen stabilized intermetallic compound having the formula (Zr.sub.1-x Ti.sub.x).sub.2-u (V.sub.1-y Fe.sub.y)O.sub.z where x=0.0 to 0.9, y=0.01 to 0.9, z=0.25 to 0.5 and u=0 to 1. The compound is capable of reversibly sorbing hydrogen at temperatures from -196.degree. C. to 200.degree. C. at pressures down to 10.sup.-6 torr. The compound is suitable for use as a hydrogen getter in low pressure, high temperature applications such as magnetic confinement fusion devices.

Mendelsohn, Marshall H. (Woodridge, IL); Gruen, Dieter M. (Downers Grove, IL)

1982-01-01T23:59:59.000Z

495

Jupiter Oxygen Corporation | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to:46 - 429 Throttled (botOpen6 Climate ZoneJeromeCounty isJupiter Oxygen Corporation

496

Comparison of atmospheric hydrology over convective continental regions using water vapor isotope measurements from space  

E-Print Network [OSTI]

. Correlation analysis shows that mixing with boundary layer air, enhanced isotopic fractionation during precipitation, and subsiding air parcels contribute to intraseasonal isotopic variability. These local controls distillation in a Lagrangrian framework underestimates the observed isotopic depletion during the monsoons

497

GEOCHEMISTRY AND ISOTOPE HYDROLOGY OF GROUNDWATERS IN THE STRIPA GRANITE RESULTS AND PRELIMINARY INTERPRETATION  

E-Print Network [OSTI]

S. Italy). In Isotope Hydrology, IAEA Symposium. Sm-129/53,isotopic variations in hydrology. At. Energy Rev. 14: 621-70 GEOCHEMISTRY AND ISOTOPE HYDROLOGY OF GROUNDWATERS IN THE

Fritz, P.

2011-01-01T23:59:59.000Z

498

E-Print Network 3.0 - argon isotopes Sample Search Results  

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

one of the earliest isotope... this is not always the case--see later). The naturally occurring isotopes of argon are measured by mass spectrometry... isotopes but also small...

499

E-Print Network 3.0 - argon isotopic chains Sample Search Results  

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

one of the earliest isotope... this is not always the case--see later). The naturally occurring isotopes of argon are measured by mass spectrometry... isotopes but also small...

500

Isotope Specific Remediation Media and Systems - 13614  

SciTech Connect (OSTI)

On March 11, 2011, now two years ago, the magnitude 9.0 Great East Japan earthquake, Tohoku, hit off the Fukushima coast of Japan. While, of course, most of the outcome of this unprecedented natural and manmade disaster was a negative, both in Japan and worldwide, there have been some extremely invaluable lessons learned and new emergency recovery technologies and systems developed. As always, the mother of invention is necessity. Among these developments has been the development and full-scale implementation of proven isotope specific media (ISMs) with the intent of surgically removing specific hazardous isotopes for the purpose of minimizing dose to workers and the environment. The first such ISMs to be deployed at the Fukushima site were those removing cesium (Cs-137) and iodine (I-129). Since deployment on June 17, 2011, along with treated cooling water recycle, some 70% of the curies in the building liquid wastes have been removed by the Kurion system alone. The current levels of cesium are now only 2% of the original levels. Such an unprecedented, 'external cooling system' not only allowed the eventual cold shut down of the reactors in mid-December, 2011, but has allowed workers to concentrate on the cleanup of other areas of the site. Water treatment will continue for quite some time due to continued leakage into the buildings and the eventual goal of cleaning up the reactors and fuel pools themselves. With the cesium removal now in routine operation, other isotopes of concern are likely to become priorities. One such isotope is that of strontium, and yttrium (Sr-90 and Y-90), which is still at original levels causing further dose issues as well as impediments to discharge of the treated waste waters. For over a year now, a new synthetic strontium specific media has been under development and testing both in our licensed facility in Oak Ridge, Tennessee, but also in confirmatory tests by the Japan Atomic Energy Agency (JAEA) in Japan for Tokyo Electric Power Company (TEPCO). The tests have proven quite successful, even in high salt conditions, and, with loading and dose calculations being completed, will be proposed to add to the existing cesium system. There is no doubt, as high gamma isotopes are removed, other recalcitrant isotopes such as this will require innovative removal media, systems and techniques. Also coming out of this international effort are other ISM media and systems that can be applied more broadly to both Commercial Nuclear Power Plants (NPPs) as well as in Department of Energy (DOE) applications. This cesium and strontium specific media has further been successfully tested in 2012 at a Magnox station in the UK. The resulting proposed mitigation systems for pond and vault cleanup look quite promising. An extremely unusual ISM for carbon 14 (C-14), nickel (Ni-63) and cesium (Cs-137) has been developed for Diablo Canyon NPP for dose reduction testing in their fuel pool. These media will be deployed in Submersible Media Filter (SMF) and Submersible Columns (SC) systems adapted to standard Tri-Nuclear{sup R} housings common in the U.S. and UK. External Vessel Systems (mini-Fukushima) have also been developed as a second mitigation system for D and D and outages. Finally, technetium (Tc- 99) specific media developed for the Waste Treatment Plant (WTP) recycle or condensate (secondary) waste streams (WM 2011) are being further perfected and tested for At-Tank Tc-99 removal, as well as At Tank Cs media. In addition to the on-going media development, systems for deploying such media have developed over the last year and are in laboratory- and full-scale testing. These systems include the fore mentioned Submersible Media Filters (SMF), Submersible Columns (SC) and external pilot- and full-scale, lead-lag, canister systems. This paper will include the media development and testing, as well as that of the deployment systems themselves. (authors)

Denton, Mark S.; Mertz, Joshua L. [Kurion, Inc. Oak Ridge, Tennessee 37831 (United States)] [Kurion, Inc. Oak Ridge, Tennessee 37831 (United States); Morita, Keisuke [Japan Atomic Energy Agency, Tokai Research and Development Center, Fukushima Project Team, Tokai-mura, Ibaraki-ken, 319-1195 (Japan)] [Japan Atomic Energy Agency, Tokai Research and Development Center, Fukushima Project Team, Tokai-mura, Ibaraki-ken, 319-1195 (Japan)

2013-07-01T23:59:59.000Z