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1

Oxygen Isotope Evidence For Past And Present Hydrothermal Regimes Of Long  

Open Energy Info (EERE)

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

2

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

SciTech Connect (OSTI)

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

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

2008-02-21T23:59:59.000Z

3

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

SciTech Connect (OSTI)

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

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

1993-02-01T23:59:59.000Z

4

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

Science Journals Connector (OSTI)

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

2000-01-04T23:59:59.000Z

5

Device and method for separating oxygen isotopes  

DOE Patents [OSTI]

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

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

1984-01-01T23:59:59.000Z

6

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

7

Isotope Evidence for Ozone Formation on Surfaces  

Science Journals Connector (OSTI)

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

Christof Janssen; Béla Tuzson

2010-05-06T23:59:59.000Z

8

It's Elemental - Isotopes of the Element Oxygen  

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

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

9

Geothermal reservoir temperatures estimated from the oxygen isotope...  

Open Energy Info (EERE)

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

10

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

11

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

Science Journals Connector (OSTI)

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

Anatoly L. Buchachenko; Elena O. Dubinina

2011-03-30T23:59:59.000Z

12

Geothermal reservoir temperatures estimated from the oxygen isotope  

Open Energy Info (EERE)

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

13

Oxygen And Carbon Isotope Ratios Of Hydrothermal Minerals From Yellowstone  

Open Energy Info (EERE)

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

14

Hydrogen, Oxygen and Silicon Isotope Systematics in Lunar Material  

Science Journals Connector (OSTI)

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

1977-01-01T23:59:59.000Z

15

Oxygen isotope records of carboniferous seasonality on the Russian platform  

E-Print Network [OSTI]

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

Wang, Huayu

2012-06-07T23:59:59.000Z

16

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

17

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

18

Oxygen-Isotope Exchange between CO2 and Solid Ti18O2  

Science Journals Connector (OSTI)

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

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

2011-05-17T23:59:59.000Z

19

INTRODUCTION The oxygen isotopic compositions of minerals  

E-Print Network [OSTI]

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

González, Luis A.

20

Atmospheric Oxygen: Isotopic Composition and Solubility Fractionation  

Science Journals Connector (OSTI)

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

P. Kroopnick; H. Craig

1972-01-07T23:59:59.000Z

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

Exploring Neutron-Rich Oxygen Isotopes with MoNA  

E-Print Network [OSTI]

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

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

2007-08-20T23:59:59.000Z

22

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

23

Lead and strontium isotopic evidence for crustal interaction...  

Open Energy Info (EERE)

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

24

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

E-Print Network [OSTI]

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

Roth, Justine P.

25

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.

26

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

27

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.

28

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

Science Journals Connector (OSTI)

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

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

2014-10-01T23:59:59.000Z

29

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

E-Print Network [OSTI]

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

Wohlfarth, Barbara

30

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

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

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

31

Lead and strontium isotopic evidence for crustal interaction and  

Open Energy Info (EERE)

Lead and strontium isotopic evidence for crustal interaction and Lead 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, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Lead 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, California Details Activities (1) Areas (1) Regions (0) Abstract: The isotopic compositions of Pb and Sr in Pleistocene basalt, high-silica rhyolite, and andesitic inclusions in rhyolite of the Coso volcanic field indicate that these rocks were derived from different levels of compositionally zoned magmatic systems. The 2 earliest rhyolites

32

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

33

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

34

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

Science Journals Connector (OSTI)

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

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

2013-02-01T23:59:59.000Z

35

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

Science Journals Connector (OSTI)

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

Hisayoshi Yurimoto; Motoo Ito; Hiroshi Nagasawa

1998-12-04T23:59:59.000Z

36

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.

37

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

Open Energy Info (EERE)

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

38

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.

39

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

E-Print Network [OSTI]

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

Kobashi, Takuro

2012-06-07T23:59:59.000Z

40

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

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 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...

42

An Oxygen Isotope Study Of Hydrothermal Alteration In The Lake City  

Open Energy Info (EERE)

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

43

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

44

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

Science Journals Connector (OSTI)

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

L. W. Cooper; M. J. DeNiro

1989-05-01T23:59:59.000Z

45

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

Science Journals Connector (OSTI)

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

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

1997-08-01T23:59:59.000Z

46

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

SciTech Connect (OSTI)

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

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

1994-09-01T23:59:59.000Z

47

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.

48

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

49

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

50

Evidence of natural isotopic distribution from single-molecule SERS  

E-Print Network [OSTI]

We report on the observation of the natural isotopic spread of carbon from single-molecule Surface Enhanced Raman Spectroscopy (SM-SERS). By choosing a dye molecule with a very localized Raman active vibration in a cyano bond (C$\\equiv$N triple bond), we observe (in a SERS colloidal liquid) a small fraction of SM-SERS events where the frequency of the cyano mode is softened and in agreement with the effect of substituting $^{12}$C by the next most abundant $^{13}$C isotope. This example adds another demonstration of single molecule sensitivity in SERS through isotopic editing which is done, in this case, not by artificial isotopic editing but rather by nature itself. It also highlights SERS as a unique spectroscopic tool, capable of detecting an isotopic change in one atom of a single molecule.

P. G. Etchegoin; E. C. Le Ru; M. Meyer

2008-11-03T23:59:59.000Z

51

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

SciTech Connect (OSTI)

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

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

2012-01-01T23:59:59.000Z

52

Evidence of magnetic isotope effects during thermochemical sulfate reduction  

E-Print Network [OSTI]

Thermochemical sulfate reduction experiments with simple amino acid and dilute concentrations of sulfate reveal significant degrees of mass-independent sulfur isotope fractionation. Enrichments of up to 13‰ for [superscript ...

Oduro, Harry D.

53

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.

54

Molecular carbon isotopic evidence for the origin of geothermal hydrocarbons  

Science Journals Connector (OSTI)

... in the flask's headspace. This procedure produced negligible amounts of contaminating hydrocarbons. The geothermal hydrocarbons were separated and combusted, and the carbon dioxide product purified and measured using ... of the pyrolysis and spark discharge experiments, b, Isotopic abundance of hydrocarbons from four geothermal localities as follows: D, Cerro Prieto, well M-5, sampled January 1979; ...

David J. Des Marais; Jason H. Donchin; Nancy L. Nehring; Alfred H. Truesdell

1981-08-27T23:59:59.000Z

55

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...

56

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

SciTech Connect (OSTI)

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

Lee, J.

1981-01-01T23:59:59.000Z

57

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

E-Print Network [OSTI]

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

Paytan, Adina

58

Isotope studies in photosynthesis  

Science Journals Connector (OSTI)

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

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

1953-01-01T23:59:59.000Z

59

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

60

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

E-Print Network [OSTI]

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

Kan, Cynthia

2009-01-01T23:59:59.000Z

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

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

Science Journals Connector (OSTI)

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

Ilya N. Bindeman; John W. Valley

2002-11-01T23:59:59.000Z

62

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

Science Journals Connector (OSTI)

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

Sarah Tynan; Andrea Dutton; Stephen Eggins; Bradley Opdyke

2014-01-01T23:59:59.000Z

63

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

Science Journals Connector (OSTI)

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

Nicholas P. Jew; Jon M. Erlandson…

2014-09-01T23:59:59.000Z

64

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

Science Journals Connector (OSTI)

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

Giulia de Petris; Anna Troiani

2008-03-05T23:59:59.000Z

65

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

E-Print Network [OSTI]

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

66

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

67

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

68

Isotope Analysis  

Science Journals Connector (OSTI)

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

Tandong Yao; Wusheng Yu; Huabiao Zhao…

2014-08-01T23:59:59.000Z

69

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

70

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

E-Print Network [OSTI]

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

Ehleringer, Jim

71

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

Science Journals Connector (OSTI)

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

Richard B. Alley; Kurt M. Cuffey

72

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

Science Journals Connector (OSTI)

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

David A. Fisher

1979-01-01T23:59:59.000Z

73

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

SciTech Connect (OSTI)

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

Kurz, J.L.; Lee, J.

1980-07-30T23:59:59.000Z

74

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

75

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

76

Isotopic evidence for the source of lead in the North Pacific abyssal water  

E-Print Network [OSTI]

The absence of accurate measurements of lead (Pb) isotopic composition in the pristine North Pacific abyssal water has made it difficult to assess the relative importance of what are believed to be the two major Pb sources: ...

Wu, Jingfeng

77

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

78

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

Science Journals Connector (OSTI)

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

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

2014-09-01T23:59:59.000Z

79

How surface complexes impact boron isotope fractionation: Evidence from Fe and Mn oxides sorption experiments  

Science Journals Connector (OSTI)

Although the pH-dependence of boron isotope fractionation between solution and precipitating minerals has been widely used in Earth Sciences, especially for reconstructing ancient seawater pH, the mechanisms by which boron adsorbs on solids or coprecipitates in minerals are still poorly known. Here we have investigated boron isotopic fractionation during its adsorption on goethite (?-FeOOH) and birnessite (K0.1MnO2.2,0.9H2O) as a function of solution pH at T = 25 °C and I = 0.1 M. Maximum partition coefficients (Kd) between adsorbed and aqueous boron, equal to 39 and 34 for goethite and birnessite, respectively, are observed at pH = 8–9. B adsorption at the surface of goethite induces its strong pH-dependent isotopic fractionation ranging from ? = ? 40‰ (10B enrichment on goethite) at pH  10. During adsorption on birnessite at acid and neutral pH, boron isotopic fractionation is lower than during its sorption on goethite (? = ? 15‰), decreases (? increases) with increasing pH above pH = 8, and reverses at pH > 9: 11B enrichment (+ 23‰ at pH = 10.8) is observed at birnessite surface. Based on combined infrared (DRIFT) spectroscopic analysis and modeling of B speciation at oxides–solution interfaces, the observed isotopic fractionations can be rationalized by the formation of trigonal and tetrahedral boron inner-sphere complexes on goethite surface, and tetrahedral inner-sphere and trigonal outer-sphere and inner-sphere complexes on birnessite surface. B isotopic fractionation is strongly dependent on the structure of surface complexes formed: the high steric strain induced by the formation of trigonal boron bidendate binuclear complexes at goethite surface leads to a much higher isotopic fractionation (isotopically lighter sorbed boron) than that following the formation of tetrahedral bidendate binuclear complexes. Conversely, the formation at birnessite surface of trigonal complexes, having almost the same isotopic composition than aqueous boric acid, accounts for the heavier isotopic composition of birnessite than goethite boron, both at acid and alkaline pH. These results show that, in nature, 11B enrichment is expected in waters in equilibrium with iron or manganese oxides and that this enrichment is a function of pH that changes boron speciation in solution and at solid surfaces. This is typically the case for soil solution in Fe- and Mn-rich environments and in seawater. In addition, the markedly different isotopic fractionation factor, at the same pH, of boron sorbed on goethite and birnessite (at pH = 8.2, ? is equal to 0.967 and 0.986 for goethite and birnessite, respectively) may be used to determine past ocean pH values without requiring knowledge of past isotopic composition.

Emmanuel Lemarchand; Jacques Schott; Jérôme Gaillardet

2007-01-01T23:59:59.000Z

80

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

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

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

82

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

E-Print Network [OSTI]

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

Goldsmith, Greg

83

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

84

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

E-Print Network [OSTI]

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

Goddard III, William A.

85

The antiquity of oxygenic photosynthesis: Evidence from stromatolites in sulphate-deficient Archaean lakes  

SciTech Connect (OSTI)

The Tumbiana Formation, about 2,700 million years old, was largely deposited in ephemeral saline lakes, as judged by the unusual evaporite paragenesis of carbonate and halite with no sulfate. Stromatolites of diverse morphology occur in the lacustrine sediments, some with palimpsest fabrics after erect filaments. These stromatolites were probably accreted by phototropic microbes that, from their habitat in shallow isolated basins with negligible sulfate concentrations, almost certainly metabolized by oxygenic photosynthesis.

Buick, R. (Harvard Univ., Cambridge, MA (United States))

1992-01-03T23:59:59.000Z

86

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

SciTech Connect (OSTI)

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

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

1994-11-01T23:59:59.000Z

87

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

88

Carbon Isotopes  

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

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

89

unstable isotope  

Science Journals Connector (OSTI)

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

2014-08-01T23:59:59.000Z

90

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

E-Print Network [OSTI]

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

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

2010-06-15T23:59:59.000Z

91

Evidence for low-temperature isotopic ordering in methyl-monodeuterated lithium acetate dihydrate  

Science Journals Connector (OSTI)

We measured the heat capacities of methyl-monodeuterated lithium acetate dihydrate single crystals (LiC2H2DO2·2H2O) at 2 K < T < 20 K and Raman spectra at ambient conditions. Significant excess heat capacities were found at T = 14.5 K and 5.5 K. The thermodynamic data is compared to that of fully protonated and fully deuterated LiAc and interpreted in terms of phase transitions between a classical dynamically disordered phase above 14.5 K, a phase stable between 14.5 K and 5.5 K in which there is quantum tunnelling of the methyl groups, and an isotopically ordered phase below 5.5 K.

F. Schröder; B. Winkler; J.D. Bauer; E. Haussühl; B. Rivera Escoto; F. Tristan López; M. Avalos Borja; C. Richter; J. Ferner

2012-01-01T23:59:59.000Z

92

Lead Isotopic Composition of Trinitite Melt Glass: Evidence for the Presence of Canadian Industrial Lead in the First Atomic Weapon Test  

Science Journals Connector (OSTI)

Lead Isotopic Composition of Trinitite Melt Glass: Evidence for the Presence of Canadian Industrial Lead in the First Atomic Weapon Test ... (1-7) The PDMs produced subsequent to the first atomic weapon test, Trinity, are available for public research. ... The Trinity atomic weapon test took place on July 16, 1945, at 5:29:45 a.m. ...

Jeremy J. Bellucci; Antonio Simonetti; Christine Wallace; Elizabeth C. Koeman; Peter C. Burns

2013-07-05T23:59:59.000Z

93

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

Open Energy Info (EERE)

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

94

Nitrogen isotopes in the recent solar wind from the analysis of genesis targets: evidence for large scale isotope heterogeneity in the nascent solar system  

SciTech Connect (OSTI)

Nitrogen, the fifth most abundant element in the universe, displays the largest stable isotope variations in the solar system reservoirs after hydrogen. Yet the value of isotopic composition of solar nitrogen, presumably the best proxy of the protosolar nebula composition, is not known. Nitrogen isotopes trapped in Genesis spacecraft target material indicate a 40 % depletion of {sup 15}N in solar wind N relative to inner planets and meteorites, and define a composition for the present-day Sun undistinguishable from that of Jupiter's atmosphere. These results indicate that the isotopic composition of of nitrogen in the outer convective zone of the Sun (OCZ) has not changed through time, and is representative of the protosolar nebula. Large {sup 15}N enrichments during e.g., irradiation, or contributions from {sup 15}N-rich presolar components, are required to account for planetary values.

Wiens, Roger C [Los Alamos National Laboratory; Marty, Bernard [INSU-CNRS; Zimmermann, Laurent [INSU-CNRS; Burnard, Peter G [INSU-CNRS; Burnett, Donald L [CALTECH; Heber, Veronika S [ETH ZURICH; Wieler, Rainer [ETH ZURICH; Bochsler, Peter [UNIV OV BERN

2009-01-01T23:59:59.000Z

95

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

Science Journals Connector (OSTI)

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

Castrillo, Antonio; Casa, Giovanni; Gianfrani, Livio

2007-01-01T23:59:59.000Z

96

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

97

Detailed Atmosphere Modeling for the Neutron Star 1E1207.4–5209: Evidence of Oxygen/Neon Atmosphere  

Science Journals Connector (OSTI)

We present a comprehensive investigation of the two broad absorption features observed in the X-ray spectrum of the neutron star 1E1207.4-5209 based on a recent analysis of the 260 ks XMM-Newton data by Mori et al. Expanding on earlier work by Hailey & Mori, we have examined all previously proposed atmospheric models for 1E1207.4-5209. Using our atomic code, which rapidly solves Schrödinger's equation for arbitrary ions in strong magnetic field, we have systematically constructed atmospheric models by calculating polarization-dependent LTE opacities and addressed all the physics relevant to strongly magnetized plasmas. We have been able to rule out virtually all atmospheric models because they either do not sustain an ionization balance consistent with the claimed atmosphere composition or because they predict line strengths and line widths that are inconsistent with the data. Only oxygen or neon atmospheres at B ~ 1012 G provide self-consistent atmospheric solutions of the appropriate ionization balance that also have line widths, strengths, and energies consistent with the observations. The observed features are likely composed of several bound-bound transition lines from highly ionized oxygen/neon, and they are broadened primarily by motional Stark effects and magnetic field variation over the line-emitting region. Further considerations of plausible mechanisms for the formation of a mid-Z atmosphere likely rule out neon atmospheres and have important implications for the fallback mechanism in supernova ejecta. Future high-resolution spectroscopy missions such as Constellation-X will be able to resolve predicted substructure in the absorption features and will measure magnetic field strength and gravitational redshift independently to better than 10% accuracy.

Kaya Mori; Charles J. Hailey

2006-01-01T23:59:59.000Z

98

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

Science Journals Connector (OSTI)

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

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

2014-07-30T23:59:59.000Z

99

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

100

Nuclear isotope thermometry  

Science Journals Connector (OSTI)

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

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

2000-11-10T23:59:59.000Z

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

Millennial-scale isotope records from a wide-ranging predator show evidence of recent human impact to oceanic food webs  

Science Journals Connector (OSTI)

...Point. Stable Isotope and Accelerator Mass Spectrometry Radiocarbon...and dried at 25 °C in a vacuum oven. Stable isotope data were...CO 2 , and graphitized for Accelerator Mass Spectrometry (AMS) dating...before the age of atmospheric nuclear bomb testing. All radiocarbon...

Anne E. Wiley; Peggy H. Ostrom; Andreanna J. Welch; Robert C. Fleischer; Hasand Gandhi; John R. Southon; Thomas W. Stafford; Jr.; Jay F. Penniman; Darcy Hu; Fern P. Duvall; Helen F. James

2013-01-01T23:59:59.000Z

102

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

Science Journals Connector (OSTI)

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

Wenfeng Deng; Gangjian Wei

2014-08-01T23:59:59.000Z

103

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

Open Energy Info (EERE)

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

104

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

Open Energy Info (EERE)

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

105

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

Open Energy Info (EERE)

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

106

Source components of the Gran Canaria (Canary Islands) shield stage magmas: evidence from olivine composition and Sr–Nd–Pb isotopes  

Science Journals Connector (OSTI)

The Canary Island primitive basaltic magmas are thought to be derived from an HIMU-type upwelling mantle containing isotopically depleted (NMORB)-type component having interacted with an enriched (EM)-type com...

Andrey A. Gurenko; Kaj A. Hoernle…

2010-05-01T23:59:59.000Z

107

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.

108

Isotope Fractionation of Water during Evaporation without Condensation  

Science Journals Connector (OSTI)

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

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

2005-12-03T23:59:59.000Z

109

Nd-isotope evidence for the distal provenance of the historical (c. <3000 BP) lateritic surface cover underlying the Equatorial forest in Gabon (Western Africa)  

Science Journals Connector (OSTI)

Abstract Surficial formations in Gabon, as well as in other places of western Central Africa include a ubiquitous, homogeneous and 1–3 m-thick clayey to sandy lateritic surface cover known as the ‘Cover Horizon’. From 14C radiometric dating it has been concluded that the emplacement of this unit was correlative with a major environmental crisis which affected Central Africa c. 3000–2000 years ago. 10Be and Nd-isotopic analyses have been performed to provide new constraints on the age and origin of this layer. Six samples from two depth profiles investigated for 10Be exhibit an almost constant concentration consistent with a very recent deposition age. Nd-isotopic analyses performed on the silt to clay fraction of eleven samples from widely spaced locations over Gabon attest for mildly radiogenic signatures (?Nd = ?23 to ?17) in ten of them, and a slightly radiogenic signature (?Nd = ?9) in one sample. TDM model ages range from 1.6 to 2.6 Ga, and a perfect discrimination is observed between the Nd-isotopic signature of the Cover Horizon and that of the underlying Congo Craton. This makes an aeolian origin as the most probable for the Cover Horizon. The average ?Nd (c. ?20) is however rather unusual for aeolian sediments or aerosols. A possible source of particles is therefore tested by considering the present-day atmospheric flux over Gabon and adjacent regions. Combined atmospheric modeling and Nd-isotopes leads to the conclusion that the fine fraction of the Cover Horizon could have originated from the northern part of the Namib desert.

D. Thiéblemont; C. Guerrot; Ph. Négrel; R. Braucher; D.L. Bourlès; R. Thiéblemont

2014-01-01T23:59:59.000Z

110

Trace element disequilibria and magnesium isotope heterogeneity in 3655A: Evidence for a complex multi-stage evolution of a typical Allende Type B1 CAI  

SciTech Connect (OSTI)

We used the Panurge ion microprobe to measure concentrations of the rare earth elements (REEs), Ba, Hf, and Sr in melilite, clinopyroxene. plagioclase, and perovskite and Mg isotopes in plagioclase, spinel, melilite, fassaite, hibonite, grossular, and monticellite from the Allende Type B1 calcium-, aluminum-rich inclusion (CAI), USNM 3655A. The distribution and concentration of Ba and the REE in melilite from the melilite-rich mantle of 3655A are unlike those predicted from melilite-melt REE partitioning experiments for closed system crystal fractionation. REE concentrations are lower than expected in the first crystallized gehlenitic melilite, increase rapidly to higher than expected concentrations in melilite with intermediate akermanite contents (Ak30-Ak40), and decrease as expected only during the late stage of mantle crystallization. Barium concentrations in melilite are 10-50 times those expected, and the LREE/HREE ratio increases continuously rather than remaining constant. The unexpected distribution of trace elements in melilite reflects a progressive enrichment of trace elements in the melt during the early stages of crystallization. A partial explanation for this observation is the dissolution of precursor perovskite that contained half or more of the total REE budget of the inclusion. The Mg isotope record of 3655A is distinguished by four salient features: (1) large {sup 26}Mg excesses correlated with the respective Al/Mg ratios in plagioclase, melilite, and hibonite, (2) F{sub Mg}, the mass-dependent fractionation of Mg, is positive. with enrichment of the heavier Mu isotopes in all primary phases, (3) a heterogeneous distribution of F{sub Mg} values. with F{sub Mg} in melilite systematically greater than in either spinel or fassaite, and (4) isotopically normal Mg in the secondary alteration phases, grossular and monticellite. 81 refs., 9 figs., 8 tabs.

Kennedy, A.K.; Hutcheon, I.D.; Beckett, J.R. [California Institute of Technology, Pasadena, CA (United States)] [and others] [California Institute of Technology, Pasadena, CA (United States); and others

1997-04-01T23:59:59.000Z

111

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

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 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

113

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.

114

It's Elemental - The Element Oxygen  

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

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

115

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...

116

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

117

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

E-Print Network [OSTI]

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

Banner, Jay L.

118

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

119

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

Open Energy Info (EERE)

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

120

Isotopic Analysis- Fluid At Indian Valley Hot Springs Geothermal Area  

Open Energy Info (EERE)

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

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

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

Open Energy Info (EERE)

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

122

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

123

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.

124

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

125

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

126

lead-isotope dating  

Science Journals Connector (OSTI)

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

2014-08-01T23:59:59.000Z

127

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...

128

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

129

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

130

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

131

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

132

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

Open Energy Info (EERE)

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

133

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones  

Science Journals Connector (OSTI)

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

H. Bocherens; D.G. Drucker

2007-01-01T23:59:59.000Z

134

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones  

Science Journals Connector (OSTI)

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

H. Bocherens; D.G. Drucker

2013-01-01T23:59:59.000Z

135

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

136

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

137

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

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

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

138

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

Open Energy Info (EERE)

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

139

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...

140

Isotopically pumped isotopic CF4 laser  

Science Journals Connector (OSTI)

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

Eckhardt, Roger; Telle, John; Haynes, Larry

1982-01-01T23:59:59.000Z

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.


141

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

142

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

143

Isotope Geothermometry | Open Energy Information  

Open Energy Info (EERE)

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

144

It's Elemental - Isotopes of the Element Nitrogen  

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

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

145

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

146

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

147

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

148

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

149

Electrochemical Isotope Effect and Lithium Isotope Separation  

Science Journals Connector (OSTI)

In a series of papers Kavner et al. (2005, 2008)(2, 3) derive an equation predicting isotopic fractionation due to an electrochemical isotope effect (?EIE), defined by the ratio of electron transfer rates (k?/k) for isotopically substituted species (prime for heavy isotopologues): where v, ?G, kB, T, m, ?eq, QP/QR, z, e, and ? denote collision frequency, activation free energy, Boltzmann’s constant, temperature, mass in motion, equilibrium fractionation factor, partition function ratio of abundant isotopologues of product (P) and reactant (R), number of electrons, charge of electron, and Marcus reorganization energy, respectively. ... fractional isotope evolution of Zn isotopes during an electroplating process which stepwise removes most of the Zn from the aq. ...

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

2009-07-06T23:59:59.000Z

150

Perchlorate Isotope Forensics  

Science Journals Connector (OSTI)

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

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

2005-11-04T23:59:59.000Z

151

Isotope Effect in Adhesion  

Science Journals Connector (OSTI)

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

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

2000-05-25T23:59:59.000Z

152

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

Open Energy Info (EERE)

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

153

Isotopic Resonance Hypothesis: Experimental Verification by Escherichia coli Growth Measurements  

E-Print Network [OSTI]

Isotopic composition of reactants affects the rates of chemical and biochemical reactions. As a rule, enrichment of heavy stable isotopes leads to slower reactions. But the recent isotopic resonance hypothesis suggests that the dependence of the reaction rate upon the enrichment degree is not monotonous; instead, at some resonance isotopic compositions, the kinetics increases, while at off resonance compositions the same reactions progress slower. To test the predictions of this hypothesis for the elements C, H, N and O, we designed a precise (standard error plus or minus 0.05%) experiment to measure the bacterial growth parameters in minimal media with varying isotopic compositions. A number of predicted resonance conditions were tested, which kinetic enhancements as strong as plus 3% discovered at these conditions. The combined evidence extremely strongly supports the existence of isotopic resonances. This phenomenon has numerous implications for the origin of life and astrobiology, and possible application...

Xie, Xueshu

2014-01-01T23:59:59.000Z

154

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

155

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

156

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

157

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...

158

ARM - Measurement - Isotope ratio  

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

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

159

Isotope Program Transportation | Department of Energy  

Office of Environmental Management (EM)

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

160

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

E-Print Network [OSTI]

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

Fantle, Matthew

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

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

162

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

163

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

164

Mass-Independent Isotope Effects  

Science Journals Connector (OSTI)

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

Anatoly L. Buchachenko

2013-01-09T23:59:59.000Z

165

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

166

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

167

Solar Activity Index: Validity Supported by Oxygen Isotope Dating  

Science Journals Connector (OSTI)

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

J. R. Bray

1970-05-01T23:59:59.000Z

168

Method for the Analysis of Oxygen Isotopic Composition of Soil  

E-Print Network [OSTI]

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

Paytan, Adina

169

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

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

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

170

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

171

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...

172

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

173

Chemical And Isotopic Investigation Of Warm Springs Associated With Normal  

Open Energy Info (EERE)

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

174

NIDC: Online Catalog of Isotope Products | Product List  

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

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

175

Mantle Helium And Carbon Isotopes In Separation Creek Geothermal Springs,  

Open Energy Info (EERE)

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

176

Celebrating The Isotope  

Science Journals Connector (OSTI)

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

GEORGE B. KAUFFMAN

2013-12-02T23:59:59.000Z

177

Isotope - based Quantum Information  

E-Print Network [OSTI]

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

Vladimir G. Plekhanov

2009-09-04T23:59:59.000Z

178

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

179

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

180

Plants making oxygen  

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

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

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

Algae for Oxygen  

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

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

182

lead-isotope age  

Science Journals Connector (OSTI)

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

2014-08-01T23:59:59.000Z

183

ISOTOPES IN WATER  

Science Journals Connector (OSTI)

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

W. GEORGE DARLING; ADRIAN H. BATH…

2006-01-01T23:59:59.000Z

184

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

185

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

186

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

Open Energy Info (EERE)

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

187

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

188

Atomic Spectroscopy and Separated Isotopes  

Science Journals Connector (OSTI)

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

J. R. McNally Jr.

1952-01-01T23:59:59.000Z

189

Radioactive Kr Isotopes  

Science Journals Connector (OSTI)

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

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

1948-10-01T23:59:59.000Z

190

Solar energy: Hydrogen and oxygen  

Science Journals Connector (OSTI)

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

John J. Farrell

1982-01-01T23:59:59.000Z

191

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

192

Optical oxygen concentration monitor  

DOE Patents [OSTI]

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

Kebabian, P.

1997-07-22T23:59:59.000Z

193

Isotope separation apparatus  

DOE Patents [OSTI]

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

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

1980-01-01T23:59:59.000Z

194

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

195

Oxygen in Underwater Cave  

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

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

196

Isotope Effect of Mercury Diffusion in Air  

Science Journals Connector (OSTI)

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

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

2013-12-23T23:59:59.000Z

197

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

Open Energy Info (EERE)

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

198

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

Open Energy Info (EERE)

And Local Trends In Helium Isotopes, Basin And Range Province, And Local Trends In Helium Isotopes, Basin And Range Province, Western North America- Evidence For Deep Permeable Pathways Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Regional And Local Trends In Helium Isotopes, Basin And Range Province, Western North America- Evidence For Deep Permeable Pathways Details Activities (1) Areas (1) Regions (0) Abstract: Fluids from the western margin of the Basin and Range have helium isotope ratios as high as ~6-7 Ra, indicating a strong mantle melt influence and consistent with recent and current volcanic activity. Moving away from these areas, helium isotope ratios decrease rapidly to 'background' values of around 0.6 Ra, and then gradually decrease toward the east to low values of ~0.1 Ra at the eastern margin of the Basin and

199

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

200

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

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

Isotopic Analysis At Separation Creek Area (Van Soest, Et Al., 2002) | Open  

Open Energy Info (EERE)

Isotopic Analysis At Separation Creek Area (Van Soest, Et Al., 2002) Isotopic Analysis At Separation Creek Area (Van Soest, Et Al., 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Separation Creek Area (Van Soest, Et Al., 2002) Exploration Activity Details Location Separation Creek Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful DOE-funding Unknown References M. C. van Soest, B. M. Kennedy, W. C. Evans, R. H. Mariner (2002) Mantle Helium And Carbon Isotopes In Separation Creek Geothermal Springs, Three Sisters Area, Central Oregon- Evidence For Renewed Volcanic Activity Or A Long Term Steady State System(Question) Retrieved from "http://en.openei.org/w/index.php?title=Isotopic_Analysis_At_Separation_Creek_Area_(Van_Soest,_Et_Al.,_2002)&oldid=687475"

202

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

203

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

204

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

205

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

206

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

207

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.

208

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

209

Comparisons between stable isotope tr  

Science Journals Connector (OSTI)

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

2007-05-31T23:59:59.000Z

210

Evidence for Deformed Ground States in Light Kr Isotopes  

Science Journals Connector (OSTI)

The levels in Kr74,76 were studied with in-beam ?-spectroscopy techniques and the ?+ decay of Rb76. The energies of the 21+ states in Kr74,76 deviate from smooth behavior compared with the higher spin levels. The yrast cascade B(E2)'s are highly collective. The Kr74,76 ground states have unusually large deformation. The origin of this deformation and of shape coexistence in this region is described in terms of the protons driving the deformation.

R. B. Piercey; J. H. Hamilton; R. Soundranayagam; A. V. Ramayya; C. F. Maguire; X. -J. Sun; Z. Z. Zhao; R. L. Robinson; H. J. Kim; S. Frauendorf; J. Döring; L. Funke; G. Winter; J. Roth; L. Cleemann; J. Eberth; W. Neumann; J. C. Wells; J. Lin; A. C. Rester; H. K. Carter

1981-11-23T23:59:59.000Z

211

Evidence of magnetic isotope effects during thermochemical sulfate reduction  

Science Journals Connector (OSTI)

...4). The acid/water would come from...nitrogen flow. Water lost to evaporation...mL of Milli-Q water through a septum...in ref. 38). Recovery was incomplete because...through radical condensation reactions. 1 Farquhar...Thiemens MH ( 2000 ) Atmospheric influence of Earth’s earliest...

Harry Oduro; Brian Harms; Herman O. Sintim; Alan J. Kaufman; George Cody; James Farquhar

2011-01-01T23:59:59.000Z

212

Evidence for an Ancient Osmium Isotopic Reservoir in Earth  

Science Journals Connector (OSTI)

...ophiolites in the Klamath mountains have extremely...ancient platinum group element reservoir...Oregon Josephine Creek Klamath Mountains mass spectra...platinum platinum group plutonic rocks...ophiolites in the Klamath mountains have extremely...ancient platinum group element reservoir...

Anders Meibom; Robert Frei

2002-04-19T23:59:59.000Z

213

Rotational dynamics in ammonia borane: Evidence of strong isotope effects  

SciTech Connect (OSTI)

This work reports anelastic spectroscopy measurements on the partially deuterated (ND3BH3 and NH3BD3) and perdeuterated (ND3BD3) ammonia borane (NH3BH3) compounds. The relaxations previously reported in NH3BH3 are observed in all the samples, and are ascribed to the rotational and torsional dynamics of NH(D)3BH(D)3 complexes. A new thermally activated peak appears at 70 K (for a vibration frequency of 1 kHz) in the spectrum of NH3BD3 and ND3BD3. The peak is practically a single-time Debye process, indicating absence of interaction between the relaxing units, and has a strikingly high intensity. A secondary relaxation process is also detected around 55 K. The anelastic spectrum of the ND3BH3 only displays this less intense process at 55 K. The analysis of the peaks supplies information about the dynamics of the relaxing species, and the obtained results provide indications on the effect of partial and selective deuteration on the hydrogen (deuterium) dynamics.

Cantelli, Rosario; Paolone, Annalisa; Palumbo, Oriele; Leardini, F.; Autrey, Thomas; Karkamkar, Abhijeet J.; Luedtke, Avery T.

2013-12-15T23:59:59.000Z

214

Evidence of magnetic isotope effects during thermochemical sulfate reduction  

Science Journals Connector (OSTI)

...36 : 189 – 192 . 29 Cameron JH Grace TM ( 1982 ) Sulfate reduction with carbon is strongly influenced by bed temperature . Tappi J 65 : 84 – 87 . 30 Cameron JH Grace TM ( 1983 ) Kinetic study of sulfate reduction with carbon . Ind Eng Chem Fundam 22...

Harry Oduro; Brian Harms; Herman O. Sintim; Alan J. Kaufman; George Cody; James Farquhar

2011-01-01T23:59:59.000Z

215

Isotopic Analysis- Rock At Coso Geothermal Area (1984) | Open Energy  

Open Energy Info (EERE)

Analysis- Rock At Coso Geothermal Area (1984) Analysis- Rock At Coso Geothermal Area (1984) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At Coso Geothermal Area (1984) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Isotopic Analysis- Rock Activity Date 1984 Usefulness not indicated DOE-funding Unknown Exploration Basis To analyze evidence for crustal interaction and compositional zonation in the source regions of Pleistocene basaltic and rhyolitic magmas of the Coso volcanic field Notes The isotopic compositions of Pb and Sr in Pleistocene basalt, high-silica rhyolite, and andesitic inclusions in rhyolite of the Coso volcanic field indicate that these rocks were derived from different levels of compositionally zoned magmatic systems. The two earliest rhyolites probably

216

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

217

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...

218

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

219

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

220

Advanced isotope separation  

SciTech Connect (OSTI)

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

Not Available

1982-05-04T23:59:59.000Z

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

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

222

OXYGEN ABUNDANCES IN CEPHEIDS  

SciTech Connect (OSTI)

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

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

2013-07-01T23:59:59.000Z

223

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

E-Print Network [OSTI]

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

V. Somà; A. Cipollone; C. Barbieri; P. Navrátil; T. Duguet

2013-12-07T23:59:59.000Z

224

Isotopic Analysis- Fluid | Open Energy Information  

Open Energy Info (EERE)

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

225

Isotope Development & Production | Nuclear Science | ORNL  

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

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

226

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

227

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

228

On the earliest evidence for habitual use of fire in Europe  

Science Journals Connector (OSTI)

...progress (23). At Beeches Pit, dated to Marine Isotope Stage (MIS) 11 (Dataset S1), the evidence...The Campitello finds date to the end of Marine Isotope Stage (MIS...ago (35). Pieces of flint showing use wear as a result of their probable function...

Wil Roebroeks; Paola Villa

2011-01-01T23:59:59.000Z

229

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

SciTech Connect (OSTI)

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

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

2010-04-14T23:59:59.000Z

230

BWR oxygen control demonstration program  

SciTech Connect (OSTI)

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

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

1981-05-01T23:59:59.000Z

231

Oxygen to the core  

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

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

232

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

233

Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Area (Ito &  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Area (Ito & Tanaka, 1995) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Rock At Valles Caldera - Sulphur Springs Area (Ito & Tanaka, 1995) Exploration Activity Details Location Valles Caldera - Sulphur Springs Area Exploration Technique Isotopic Analysis- Rock Activity Date Usefulness not indicated DOE-funding Unknown References Hisatoshi Ito, Kazuhiro Tanaka (1995) Insights On The Thermal History Of The Valles Caldera, New Mexico- Evidence From Zircon

234

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

E-Print Network [OSTI]

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

Zeebe, Richard E.

235

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

236

MTBE, Oxygenates, and Motor Gasoline  

Gasoline and Diesel Fuel Update (EIA)

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

237

Plants and Night Oxygen Production  

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

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

238

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

239

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

240

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

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

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

242

Isotopic Analysis- Rock | Open Energy Information  

Open Energy Info (EERE)

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

243

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.

244

Isotopes Np240 and Np241  

Science Journals Connector (OSTI)

The 1-hour neptunium activity which had previously been assigned to Np241 has been identified as the lower isomer of Np240. The decay energy of the 1-hour Np240 has been found to be 2.05 Mev compared with 2.18 Mev for that of the 7.3-min Np240. Gamma rays of energies 1160, 1000, 915, 595, 565, 435, 245, 160, and 85 kev have been found to be associated with the decay of Np240. The best value for the half-life of Np240 is 63±2 min. The isotope Np241 has been found to have a 16-min half-life with strong evidence for an isomer with a 3.4-hour half-life.

Richard M. Lessler and Maynard C. Michel

1960-04-01T23:59:59.000Z

245

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

246

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

247

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

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

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

248

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

249

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

250

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

251

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

252

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

253

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

Science Journals Connector (OSTI)

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

Abigail R. D’Ambrosia; William C. Clyde; Henry C. Fricke; Amy E. Chew

2014-01-01T23:59:59.000Z

254

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

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

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

255

Copper isotope fractionation in acid mine drainage. | EMSL  

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

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

256

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...

257

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

258

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...

259

Angling chromium to let oxygen through | EMSL  

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

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

260

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...

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

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

262

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...

263

Platinum Monolayer Electrocatalysts for Oxygen Reduction Reaction...  

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

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

264

Oxygenate Supply/Demand Balances  

Gasoline and Diesel Fuel Update (EIA)

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

265

The System Boron—Oxygen  

Science Journals Connector (OSTI)

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

Gert Heller

1993-01-01T23:59:59.000Z

266

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

267

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

268

Definition: Isotopic Analysis- Fluid | Open Energy Information  

Open Energy Info (EERE)

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

269

Definition: Isotopic Analysis | Open Energy Information  

Open Energy Info (EERE)

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

270

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

271

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

Science Journals Connector (OSTI)

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

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

2007-07-01T23:59:59.000Z

272

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

273

Researchers Directly Observe Oxygen Signature in the Oxygen-evolving  

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

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

274

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

275

Isotopic Analysis At Lassen Volcanic National Park Area (Janik & Mclaren,  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Isotopic Analysis At Lassen Volcanic National Park Area (Janik & Mclaren, 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Lassen Volcanic National Park Area (Janik & Mclaren, 2010) Exploration Activity Details Location Lassen Volcanic National Park Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful DOE-funding Unknown Notes Both fluid and gas isotopic analysis. References Cathy J. Janik, Marcia K. McLaren (2010) Seismicity And Fluid Geochemistry At Lassen Volcanic National Park, California- Evidence For Two

276

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

Open Energy Info (EERE)

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

277

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

Open Energy Info (EERE)

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

278

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.

279

The Isotope Effect in Band Spectra, IV: the Spectrum of Silicon Nitride  

Science Journals Connector (OSTI)

Silicon nitride bands.—(1) A system of bands shaded toward the red, lying between 3800 and 5300A was obtained by Jevons in 1913 by the introduction of SiCl4 vapor into active nitrogen. His measurements have been repeated and extended to all possible heads. It is important that no oxygen be present. From a sharp intense head each band decreases rapidly in intensity to zero at the null line, then increases to a maximum at about m=13 in the negative branch, in which the lines get far enough apart to be resolved. With the aid of the quantum theory, Jevons' arrangement was revised, and correct initial (n?) and final (n??) vibrational quantum numbers assigned. The null lines of the Si28N bands correspond to the wave-number equation: ??=24234.2+1016.30 n?-17.77n?2+0.410n?4-0.00487n?-1145.00n??+6.570n??2. Partial analysis of the band structure indicates that the lines of any band are given by the equation: ?=??+B?+2B?m+Cm2 where B?=0.728-0.097n? and C=-0.0121-0.0097n?+0.0053n??; from this the internuclear distance for the vibrationless SiN molecule is 1.56×10-8 cm. Additional weak heads are present whose positions agree very closely with those calculated for the isotopes Si29N and Si30N, isotope 29 being slightly the stronger. This agreement definitely excludes SiO or any other compound than SiN as the emitter of the bands, confirming the chemical evidence. The agreement is also definite, but not conclusive, evidence against the existence of half-quantum numbers for SiN, a result opposite to that for BO. Plate I shows most of the Si28N bands together with some isotope heads. The intensity distribution in each band corresponds to thermal equilibrium at about 80°C. In respect to the initial vibrational quantum number, the distribution is non-thermal and corresponds to a high effective temperature as in other cases such as BO and CN. The intensity distribution with respect to ?n is similar to that of the violet CN bands. The sequence ?n=0 is by far the strongest, other sequences of diminishing intensity being observed as far as -3 and +3 or +4. (2) New system of bands, extensive but weak, probably also due to SiN, is described. They all have double heads (??=27), are shaded toward the red and extend from the ultraviolet through the green. An equation for the heads is given. The intensity distribution is characterized by numerically large values of ?n and by the absence of the band (0?0) and some neighboring bands.

Robert S. Mulliken

1925-09-01T23:59:59.000Z

280

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

Science Journals Connector (OSTI)

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

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

2001-01-01T23:59:59.000Z

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

AVLIS enrichment of medical isotopes  

SciTech Connect (OSTI)

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

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

1996-12-31T23:59:59.000Z

282

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

283

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

284

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.

285

Hydrogen Isotopes in Lunar Volcanic Glasses and Melt Inclusions Reveal a Carbonaceous Chondrite Heritage  

Science Journals Connector (OSTI)

...2), and that the water was not completely lost...evidence that Earth’s water budget and isotopic...high-temperature convective atmospheric envelope surrounding...and simply inherited water from the proto-Earth...observations by the Gravity Recovery and Interior Laboratory...

Alberto E. Saal; Erik H. Hauri; James A. Van Orman; Malcolm J. Rutherford

2013-06-14T23:59:59.000Z

286

Magnesium Isotope Effects in Enzymatic Phosphorylation  

Science Journals Connector (OSTI)

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

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

2008-02-05T23:59:59.000Z

287

Magnetic Isotope Effect in the Photolysis of Organotin Compounds  

Science Journals Connector (OSTI)

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

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

2006-03-02T23:59:59.000Z

288

D-D fusion induced by oxygen clusters impacting deuterated ice targets  

Science Journals Connector (OSTI)

Deuterated ice targets were bombarded by oxygen clusters at incident energies of 115 and 172.5 keV per oxygen atom. The fusion yields were measured by detecting the 3-MeV protons from the D(D,p)3H channel. Comparisons of the fusion yields from clusters with those from single atoms at the same energy per oxygen atom show no evidence of collective enhancement, in disagreement with a recent report [Bae, Beuhler, Chu, Friedlander, and Friedman, Phys. Rev. A 48, 4461 (1993)].

J. F. Liang; R. Vandenbosch; D. I. Will

1995-02-01T23:59:59.000Z

289

Magnesium-Isotope Fractionation During Plant Growth  

Science Journals Connector (OSTI)

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

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

2008-10-01T23:59:59.000Z

290

Slow Neutron Scattering by the Titanium Isotopes  

Science Journals Connector (OSTI)

Neutron diffraction studies are reported on isotopically enriched samples of TiO2 from which are evaluated the coherent scattering amplitudes of the titanium isotopes. Scattering amplitudes of +0.48, +0.33, -0.58, +0.08, and +0.55×10-12 cm were established for the titanium isotopes of mass 46, 47, 48, 49, and 50, respectively. The major isotope Ti48 is thus responsible for the anomalous scattering amplitude, -0.34×10-12 cm, characteristic of the normal element. Pronounced nuclear scattering resonance effects on the observed neutron scattering are suggested to occur for most of the isotopes.

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

1960-05-01T23:59:59.000Z

291

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

292

Isotopic Constraints on the Chemical Evolution of Geothermal Fluids, Long Valley, CA  

SciTech Connect (OSTI)

A spatial survey of the chemical and isotopic composition of fluids from the Long Valley hydrothermal system was conducted. Starting at the presumed hydrothermal upwelling zone in the west moat of the caldera, samples were collected from the Casa Diablo geothermal field and a series of monitoring wells defining a nearly linear, ~;;14 km long, west-to-east trend along the proposed fluid flow path (Sorey et al., 1991). Samples were analyzed for the isotopes of water, Sr, Ca, and noble gases, the concentrations of major cations and anions and total CO2. Our data confirm earlier models in which the variations in water isotopes along the flow path reflect mixing of a single hydrothermal fluid with local groundwater. Variations in Sr data are poorly constrained and reflect fluid mixing, multiple fluid-pathways or water-rock exchange along the flow path as suggested by Goff et al. (1991). Correlated variations among total CO2, noble gases and the concentration and isotopic composition of Ca suggest progressive fluid degassing (loss of CO2, noble gases) driving calcite precipitation as the fluid flows west-to-east across the caldera. This is the first evidence that Ca isotopes may trace and provide definitive evidence of calcite precipitation along fluid flow paths in geothermal systems.

Brown, Shaun; Kennedy, Burton; DePaolo, Donald; Evans, William

2008-08-01T23:59:59.000Z

293

Definition: Isotopic Analysis- Rock | Open Energy Information  

Open Energy Info (EERE)

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

294

Diffusion in single crystals of melilite: I. Oxygen  

SciTech Connect (OSTI)

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

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

1989-09-01T23:59:59.000Z

295

Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems  

SciTech Connect (OSTI)

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

Nimz, G. J., LLNL

1998-06-01T23:59:59.000Z

296

Kinetic Isotope Effects in Cycloreversion of Rhenium (V) Diolates  

Science Journals Connector (OSTI)

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

Kevin P. Gable; Fedor A. Zhuravlev

2002-03-21T23:59:59.000Z

297

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

298

Microbial oceanography of anoxic oxygen minimum zones  

E-Print Network [OSTI]

Vast expanses of oxygen-deficient and nitrite-rich water define the major oxygen minimum zones (OMZs) of the global ocean. They support diverse microbial communities that influence the nitrogen economy of the oceans, ...

Ulloa, Osvaldo

299

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.

300

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

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

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

302

Imaging Oxygen Molecules Up Close | EMSL  

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

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

303

Fusion reactions with germanium isotopes  

Science Journals Connector (OSTI)

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

H. Esbensen

2003-09-04T23:59:59.000Z

304

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

305

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

306

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

307

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.

308

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

309

Oxygen and Nitrogen Contamination During Arc Welding  

E-Print Network [OSTI]

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

Eagar, Thomas W.

310

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

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

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

311

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

312

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

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

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

313

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

314

Nuclear Energy Protocol for Research Isotopes Owen Lowe  

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

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

315

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

316

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

317

Strategic Isotope Production | ornl.gov  

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

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

318

Electromagnetic Isotope Separation Lab (EMIS) | ORNL  

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

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

319

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

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

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

320

EIS-0249: Medical Isotopes Production Project  

Broader source: Energy.gov [DOE]

This EIS evaluates the potential environmental impacts of a proposal to establish a production capability for molybdenum-99 (Mo-99) and related medical isotopes.

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

Category:Isotope Geothermometry | Open Energy Information  

Open Energy Info (EERE)

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

322

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...

323

Science with Beams of Radioactive Isotopes  

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

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

324

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...

325

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

326

Carbon-14 production compared to oxygen isotope records from Camp Century, Greenland and Devon Island, Canada  

Science Journals Connector (OSTI)

Carbon-14 production rate variations that are not explainable by geomagnetic changes are thought to be in antiphase with solar activity and as such should be in antiphase with paleotemperature records or proxy te...

David Andrew Fisher

1982-01-01T23:59:59.000Z

327

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

E-Print Network [OSTI]

variability of regional Holocene climate modification within the Rocky Mountain region. Herein we show

Hren, Michael

328

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

329

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

Science Journals Connector (OSTI)

Fusion reactions in the crust of an accreting neutron star are an important source of heat, and the depth at which these reactions occur is important for determining the temperature profile of the star. Fusion reactions depend strongly on the nuclear charge Z. Nuclei with Z?6 can fuse at low densities in a liquid ocean. However, nuclei with Z=8 or 10 may not burn until higher densities where the crust is solid and electron capture has made the nuclei neutron rich. We calculate the S factor for fusion reactions of neutron rich nuclei including O24+O24 and Ne28+Ne28. We use a simple barrier penetration model. The S factor could be further enhanced by dynamical effects involving the neutron rich skin. This possible enhancement in S should be studied in the laboratory with neutron rich radioactive beams. We model the structure of the crust with molecular dynamics simulations. We find that the crust of accreting neutron stars may contain micro-crystals or regions of phase separation. Nevertheless, the screening factors that we determine for the enhancement of the rate of thermonuclear reactions are insensitive to these features. Finally, we calculate the rate of thermonuclear O24+O24 fusion and find that O24 should burn at densities near 1011 g/cm3. The energy released from this and similar reactions may be important for the temperature profile of the star.

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

2008-04-29T23:59:59.000Z

330

Oxygen isotope analyses and deep-sea temperature changes: implications for rates of oceanic mixing  

Science Journals Connector (OSTI)

... fluxes into the deep sea come primarily from three sources: formation of deep water, geothermal heating, and cross-thermocline diffusion20. At steady Fig. 1 Schematic heat budget of ... (Qu) is balanced by heat input from sinking near-surface water «?s), geothermal heating (Qg), and cross-thermocline diffusion (Qd). The combination of these effects ...

Alan C. Mix; Nicklas G. Pisias

1988-01-21T23:59:59.000Z

331

Oxygen isotope fractionation between amorphous silica and water at 34–93°C  

Science Journals Connector (OSTI)

... , P-3 and P-4) along the reinjection lines in the Otake and Hatchobaru geothermal power plants. Although it would have been preferable to obtain the amorphous silica at ... temperatures, these four points were the only ones available for this experiment. The same geothermal water from the Otake station flows at P-l and P-4; at P- ...

Itsuro Kita; Sachihiro Taguchi; Osamu Matsubaya

1985-03-07T23:59:59.000Z

332

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

Science Journals Connector (OSTI)

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

T. A. RAFTER; Y. MIZUTANI

1967-12-09T23:59:59.000Z

333

Effect of seawater carbonate concentration on foraminiferal carbon and oxygen isotopes  

Science Journals Connector (OSTI)

... and G. bulloides were collected by scuba divers from surface waters of the San Pedro Basin, Southern California ... , Southern California Bight, USA, and were maintained in laboratory culture at 22 ± 0.2?°C ...

Howard J. Spero; Jelle Bijma; David W. Lea; Bryan E. Bemis

1997-12-04T23:59:59.000Z

334

Equilibrium Oxygen, Hydrogen and Carbon Isotope Fractionation Factors Applicable to Geologic Systems  

Science Journals Connector (OSTI)

...temperature. The fourth term (e/2/eUi/2) varies with temperature, but is mainly...light molecules. The last term ([1-eUi]) relates to the spacing of energy levels...mode (3) f(x)gi = [(e/2)/(eUi/2)][(1-eUi)]gi. Frequencies...

Thomas Chacko; David R. Cole; Juske Horita

335

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

336

Unexpected variations in the triple oxygen isotope composition of stratospheric carbon dioxide  

Science Journals Connector (OSTI)

...1 ): 80 – 83 . 8 Clayton RN ( 2002 ) Solar System - Self-shielding in the solar nebula . Nature 415 ( 6874 ): 860 – 861...N, 118o W), Westover Air Reserve Base (Massachusetts, USA, 42° N, 72° W), and Kiruna...

Aaron A. Wiegel; Amanda S. Cole; Katherine J. Hoag; Elliot L. Atlas; Sue M. Schauffler; Kristie A. Boering

2013-01-01T23:59:59.000Z

337

Oxygen isotopic composition of chondritic interplanetary dust particles: A genetic link between carbonaceous chondrites and  

E-Print Network [OSTI]

a Lawrence Livermore National Laboratory, Glenn T. Seaborg Institute, P.O. Box 808, Livermore, CA 94550, USA

338

Oxygen Isotope Variations at the Margin of a CAI Records Circulation Within the Solar Nebula  

Science Journals Connector (OSTI)

...spinel ± hibonite of the rim that is akermanite-rich and relatively sodium-poor...reservoir. The transition from the akermanite-rich melilite layer to the spinel...exhibits a compositional range between akermanite [Ca 2 (MgSi 2 O 7 )] and gehlenite...

Justin I. Simon; Ian D. Hutcheon; Steven B. Simon; Jennifer E. P. Matzel; Erick C. Ramon; Peter K. Weber; Lawrence Grossman; Donald J. DePaolo

2011-03-04T23:59:59.000Z

339

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

340

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.

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

Oxygen isotope anomaly observed in water vapor from Alert, Canada and the implication for the stratosphere  

Science Journals Connector (OSTI)

...stratospheric input of anomalous water, injections of stratospheric tritium (mainly produced by atmospheric detonations of thermonuclear devices during 1954?1963) to various sites in Greenland and Antarctica were recorded in snow pits (e.g., ref...

Ying Lin; Robert N. Clayton; Lin Huang; Noboru Nakamura; James R. Lyons

2013-01-01T23:59:59.000Z

342

Vibrational dynamics in isotopically substituted vitreous GeO2  

Science Journals Connector (OSTI)

We report the polarized Raman spectra of vitreous Ge O216, Ge O218, Ge70O2, and Ge74O2. This yields the O16?O18 and Ge70?Ge74 isotopic shifts for nearly all vibrational modes of the pure glassy material. The shifts of the broad high-frequency (infrared-active) modes are as predicted by a nearest-neighbor central-force ideal continuous—random-network model. The shift of the broad dominant Raman line indicates a small but significant dependence on the Ge mass, and this suggests an effect of disorder not included in the central-force theory. The narrow "defect" line at 530 cm-1 appears to be all oxygen motion, and is tentatively identified with a regular ring of bonds. The narrow line at 345 cm-1 is unique in that it exhibits very little oxygen shift; it seems to consist largely of Ge motion, for which we have no firm explanation.

F. L. Galeener; A. E. Geissberger; G. W. Ogar; Jr.; R. E. Loehman

1983-10-15T23:59:59.000Z

343

Muon Capture in Oxygen-16  

Science Journals Connector (OSTI)

The muon capture rate in oxygen is used as a means for measuring the induced pseudoscalar coupling constant (CP) of weak interactions. The capture rate between the JP=0+ ground state of O16 and the 0-, 1-, 2-, and 3- states of N16 are calculated as a function of CP with different nuclear models. Using the experimental values of the transition rates, we then determine CP. We find that the transition rate, and therefore CP, depends strongly on the nuclear model. We conclude that 5

Vincent Gillet and David A. Jenkins

1965-10-11T23:59:59.000Z

344

Research with fast radioactive isotope beams at RIKEN  

Science Journals Connector (OSTI)

......moments of neutron-rich boron isotopes were measured by the...many neutron-rich isotopes. To exploit fully the...most straightforward determination of the charge distribution...called KISS (KEK isotope separation system......

Tohru Motobayashi; Hiroyoshi Sakurai

2012-01-01T23:59:59.000Z

345

Isotope-Selective Detection and Imaging of Organic Nanolayers  

Science Journals Connector (OSTI)

Isotope-Selective Detection and Imaging of Organic Nanolayers ... We show isotopic selectivity of MRFM for three nuclei, 1H, 31P, and 13C, in organic materials. ... data to further distinguish and characterize the 2 isotopes. ...

H. J. Mamin; T. H. Oosterkamp; M. Poggio; C. L. Degen; C. T. Rettner; D. Rugar

2009-07-09T23:59:59.000Z

346

Solvent Isotope-Induced Equilibrium Perturbation for Isocitrate Lyase  

Science Journals Connector (OSTI)

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

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

2013-11-21T23:59:59.000Z

347

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

SciTech Connect (OSTI)

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

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

2008-08-07T23:59:59.000Z

348

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

349

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

350

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...

351

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...

352

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...

353

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...

354

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...

355

Stable Isotope, Site-Specific Mass Tagging For Protein Identification  

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

Stable Isotope, Site-Specific Mass Tagging For Protein Identification Stable Isotope, Site-Specific Mass Tagging For Protein Identification Proteolytic peptide mass mapping as...

356

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...

357

Isotopic Analysis- Gas At Chena Geothermal Area (Kolker, Et Al...  

Open Energy Info (EERE)

Laboratory sampling and analysis of He isotopes from Chena Hot Springs. Notes Helium isotope measurements indicate there is no magmatic or mantle input at the Chena Geothermal...

358

Development of a Micropyrolyzer for Enhanced Isotope Ratio Measurement...  

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

Micropyrolyzer for Enhanced Isotope Ratio Measurement. Development of a Micropyrolyzer for Enhanced Isotope Ratio Measurement. Abstract: This paper presents design, fabrication and...

359

The Quest for the Heaviest Uranium Isotope  

E-Print Network [OSTI]

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

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

2011-07-06T23:59:59.000Z

360

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

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

Isotopic paleoceanography of the Caribbean and east Pacific: role of Panama uplift in late Neogene time  

SciTech Connect (OSTI)

Comparisons of carbon isotopic data on benthic foraminifera from Deep Sea Drilling Project sites 502 (western Caribbean) and 503 (eastern Pacific) indicate that the difference between the Atlantic and the Pacific in the per mil enrichment in carbon-13 of total dissolved carbon dioxide increased about 6 million years ago and again 3 million years ago, when the difference reached the modern level (1 per mil). Comparisons of planktonic foraminiferal oxygen isotopic data for the Caribbean and the Pacific suggest that the salinity of Caribbean surface waters began increasing 4 million years ago, possibly in response to shoaling of the Panama isthmus. These results suggest that modern circulation patterns in the Caribbean and eastern Pacific developed by 3 million years ago in concert with changing tectonic, climatic, and biogeographic patterns.

Keigwin, L.

1982-07-23T23:59:59.000Z

362

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...

363

ISOTOPES  

E-Print Network [OSTI]

Research, Division of Nuclear Sciences of the Basic Energy Sciences ProgramResearch, Division of Nuclear Sciences of the Basic Energy Sciences Program

Lederer, C. Michael

2013-01-01T23:59:59.000Z

364

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

365

ISOTOPES  

E-Print Network [OSTI]

uranium, heavy-water-moderated CANDU reactor, as contrastedis important, and in the CANDU power reactor, which uses

Lederer, C. Michael

2013-01-01T23:59:59.000Z

366

It's Elemental - Isotopes of the Element Francium  

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

Radon Radon Previous Element (Radon) The Periodic Table of Elements Next Element (Radium) Radium Isotopes of the Element Francium [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Francium has no naturally occurring isotopes. Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 199 12 milliseconds Alpha Decay > 0.00% Electron Capture No Data Available 200 49 milliseconds Alpha Decay 100.00% 201 62 milliseconds Alpha Decay 100.00% 201m 19 milliseconds Alpha Decay 100.00% 202 0.30 seconds Alpha Decay 100.00% 202m 0.29 seconds Alpha Decay 100.00% 203 0.55 seconds Alpha Decay <= 100.00% 204 1.8 seconds Alpha Decay 92.00%

367

It's Elemental - Isotopes of the Element Radon  

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

Astatine Astatine Previous Element (Astatine) The Periodic Table of Elements Next Element (Francium) Francium Isotopes of the Element Radon [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Radon has no naturally occurring isotopes. Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 193 1.15 milliseconds Alpha Decay 100.00% 194 0.78 milliseconds Alpha Decay 100.00% 195 6 milliseconds Alpha Decay 100.00% 195m 5 milliseconds Alpha Decay 100.00% 196 4.4 milliseconds Alpha Decay 99.90% Electron Capture ~ 0.10% 197 53 milliseconds Alpha Decay 100.00% 197m 25 milliseconds Alpha Decay 100.00% 198 65 milliseconds Alpha Decay No Data Available

368

Selected Isotopes for Optimized Fuel Assembly Tags  

SciTech Connect (OSTI)

In support of our ongoing signatures project we present information on 3 isotopes selected for possible application in optimized tags that could be applied to fuel assemblies to provide an objective measure of burnup. 1. Important factors for an optimized tag are compatibility with the reactor environment (corrosion resistance), low radioactive activation, at least 2 stable isotopes, moderate neutron absorption cross-section, which gives significant changes in isotope ratios over typical fuel assembly irradiation levels, and ease of measurement in the SIMS machine 2. From the candidate isotopes presented in the 3rd FY 08 Quarterly Report, the most promising appear to be Titanium, Hafnium, and Platinum. The other candidate isotopes (Iron, Tungsten, exhibited inadequate corrosion resistance and/or had neutron capture cross-sections either too high or too low for the burnup range of interest.

Gerlach, David C.; Mitchell, Mark R.; Reid, Bruce D.; Gesh, Christopher J.; Hurley, David E.

2008-10-01T23:59:59.000Z

369

A survey of alternative oxygen production technologies  

Science Journals Connector (OSTI)

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

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

2001-01-01T23:59:59.000Z

370

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

371

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

372

Oxygen penetration into the bulk of palladium  

Science Journals Connector (OSTI)

Oxygen penetration into the bulk of palladium ... During heating, the reaction rate exhibited an activity maximum at 650 K, whereas no activity maximum was found during the ... ...

C. T. Campbell; D. C. Foyt; J. M. White

1977-01-01T23:59:59.000Z

373

Oxygen-Enriched Combustion | Department of Energy  

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

tip sheet discusses how an increase in oxygen in combustion air can reduce the energy loss in the exhaust gases and increase process heating system efficiency. PROCESS HEATING...

374

Renewable Oxygenate Blending Effects on Gasoline Properties  

Science Journals Connector (OSTI)

Renewable Oxygenate Blending Effects on Gasoline Properties ... National Renewable Energy Laboratory, Golden, Colorado 80401, United States ... Energy Fuels, 2011, 25 (10), ...

Earl Christensen; Janet Yanowitz; Matthew Ratcliff; Robert L. McCormick

2011-08-16T23:59:59.000Z

375

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

376

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. 5 figures.

Tsuo, Y.S.

1991-08-20T23:59:59.000Z

377

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

378

Radon-222 Emanation and the High Apparent Lead Isotope Ages in Lunar Dust  

Science Journals Connector (OSTI)

... 232Th decay chains may be a significant mechanism for a partial redistribution of the post-radon lead daughters. Kraner2 suggested that there may be an alpha-emitting radioactive deposit on ... radioactive deposit on the lunar surface as a result of the decay in space of radon isotopes which might diffuse out of lunar surface material. Turkevich3 reported evidence for such ...

J. A. S. ADAMS; PAULO M. BARRETTO; RONALD B. CLARK; JOE S. DUVAL

1971-05-21T23:59:59.000Z

379

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

380

Direct Observation of the Oxygenated Species during Oxygen Reduction on a  

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

Direct Observation of the Oxygenated Species during Oxygen Reduction on a Direct Observation of the Oxygenated Species during Oxygen Reduction on a Platinum Fuel Cell Cathode Friday, December 20, 2013 Fuel Cell Figure 1 Figure 1. In situ x-ray spectroscopy identification and DFT simulations of oxygenated intermediates on a platinum fuel-cell cathode. The study shows that two types of hydroxyl intermediates (non-hydrated OH and hydrated OH) with distinct activities coexist on a fuel-cell cathode. The performance of polymer-electrolyte-membrane (PEM) fuel cells is limited by the reduction at the cathode of various oxygenated intermediates in the four-electron pathway of the oxygen reduction reaction. A research team led by SLAC scientists performed x-ray spectroscopy identification and DFT simulations of oxygenated intermediates on a platinum fuel-cell cathode

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

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

382

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

383

Isotopic composition of Silurian seawater  

SciTech Connect (OSTI)

Direct isotopic analyses of 21 samples of the Silurian hydrosphere preserved as fluid inclusions in Silurian halite deposits in the Michigan Basin Salina Group yield delta/sup 18/O, deltaD ranging from 0.2 to +5.9 and -26 to -73, respectively. delta/sup 18/O has the same range as observed for modern halite facies evaporite waters and is a few per thousand higher than 100 analyses of fluid inclusions in Permian halite. deltaD is about 20 to 30 per thousand lower than modern and Permian examples. The trajectory of evaporating seawater on a deltaD-delta/sup 18/O diagram initially has a positive slope of 3-6, but hooks strongly downward to negative values, the shape of the hook depending upon humidity. Halite begins to precipitate at delta values similar to those observed for the most /sup 18/O rich fluid inclusions. Subsequent evaporation yields progressively more negative delta values as observed for the fluid inclusions. The fluid inclusion data can be readily explained in terms of evaporating seawater and are consistent with the degree of evaporation deduced from measured bromide profiles. These data are strongly inconsistent with arguments that Silurian seawater was 5.5 per thousand depleted in /sup 18/O. delta/sup 18/O for evaporite waters is systematically related to that of seawater, and does not show a -5.5 per thousand shift in the Silurian, even allowing for variables which affect the isotope evaporation trajectory. The lower deltaD may indicate a component of gypsum dehydration waters or may suggest a D-depleted Silurian hydrosphere.

Knauth, L.P.; Kealy, S.; Larimer, S.

1985-01-01T23:59:59.000Z

384

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

385

Mass, energy, and exergy balance analysis of chemical looping with oxygen uncoupling (CLOU) process  

Science Journals Connector (OSTI)

Abstract Chemical looping with oxygen uncoupling (CLOU) is a promising concept for efficient combustion of solid fuels with an inherent capture of the greenhouse gas CO 2 . This paper presents a CLOU process scheme with stoichiometric mass, energy, and exergy balances. A CLOU reactor system using medium volatile bituminous coal as fuel and silica-supported CuO as an oxygen carrier is analyzed. The analysis includes the estimation of various design and operational parameters, thermal considerations, and evaluation of the overall performance. The operation of a reactor system of two interacting circulating fluidized beds (CFBs) is greatly influenced by the hydrodynamics. For the CuO oxygen carrier, the hydrodynamic operating range appeared feasible considering the maximum solid circulation rates in current CFB boilers. Depending upon the reactor temperatures, oxygen carrier inventories of 400–680 kg/MW in the system were found necessary for stoichiometric combustion of the fuel. The temperature difference between the reactors should not exceed 50 °C, as otherwise, problems may arise with the heat balance. Exergetic efficiencies in the range of 63–70% were obtained for different combinations of relevant design parameters. It is evident that the possible operating conditions in the system are closely related to the properties of the chosen oxygen carrier. However, the calculation procedure and design criteria presented here are applicable to any oxygen carrier to be used in the process.

Petteri Peltola; Tero Tynjälä; Jouni Ritvanen; Timo Hyppänen

2014-01-01T23:59:59.000Z

386

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

387

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

388

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

389

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.

390

Singlet oxygen luminescence detection with a fibre-coupled superconducting  

E-Print Network [OSTI]

Singlet oxygen luminescence detection with a fibre-coupled superconducting nanowire single Triplet State Singlet State 1O2 Ground State Oxygen 3O2 Singlet oxygen Free space singlet oxygen luminescence detection Fibre-based singlet oxygen luminescence detection References Superconducting Detector

Greenaway, Alan

391

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

392

Laser Ablation Molecular Isotopic Spectrometry: Parameter influence on boron isotope measurements  

Science Journals Connector (OSTI)

Laser Ablation Molecular Isotopic Spectrometry (LAMIS) was recently reported for optical isotopic analysis of condensed samples in ambient air and at ambient pressure. LAMIS utilizes molecular emissions which exhibit larger isotopic spectral shits than in atomic transitions. For boron monoxide 10BO and 11BO, the isotopic shifts extend from 114 cm?1 (0.74 nm) to 145–238 cm?1 (5–8 nm) at the B 2?+ (v = 0) ? X 2?+ (v = 2) and A 2?i (v = 0) ? X 2?+ (v = 3) transitions, respectively. These molecular isotopic shifts are over two orders of magnitude larger than the maximum isotopic shift of approximately 0.6 cm?1 in atomic boron. This paper describes how boron isotope abundance can be quantitatively determined using LAMIS and how atomic, ionic, and molecular optical emission develops in a plasma emanating from laser ablation of solid samples with various boron isotopic composition. We demonstrate that requirements for spectral resolution of the measurement system can be significantly relaxed when the isotopic abundance ratio is determined using chemometric analysis of spectra. Sensitivity can be improved by using a second slightly delayed laser pulse arriving into an expanding plume created by the first ablation pulse.

Xianglei Mao; Alexander A. Bol'shakov; Dale L. Perry; Osman Sorkhabi; Richard E. Russo

2011-01-01T23:59:59.000Z

393

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

394

It's Elemental - Isotopes of the Element Magnesium  

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

Sodium Sodium Previous Element (Sodium) The Periodic Table of Elements Next Element (Aluminum) Aluminum Isotopes of the Element Magnesium [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 24 78.99% STABLE 25 10.00% STABLE 26 11.01% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 19 4.0 picoseconds Double Proton Emission 100.00% 20 90.8 milliseconds Electron Capture 100.00% Electron Capture with delayed Proton Emission ~ 27.00% 21 122 milliseconds Electron Capture 100.00% Electron Capture with delayed Proton Emission 32.60% Electron Capture with delayed Alpha Decay < 0.50%

395

It's Elemental - Isotopes of the Element Chlorine  

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

Sulfur Sulfur Previous Element (Sulfur) The Periodic Table of Elements Next Element (Argon) Argon Isotopes of the Element Chlorine [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 35 75.76% STABLE 37 24.24% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 28 No Data Available Proton Emission (suspected) No Data Available 29 < 20 nanoseconds Proton Emission No Data Available 30 < 30 nanoseconds Proton Emission No Data Available 31 150 milliseconds Electron Capture 100.00% Electron Capture with delayed Proton Emission 0.70% 32 298 milliseconds Electron Capture 100.00%

396

It's Elemental - Isotopes of the Element Potassium  

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

Argon Argon Previous Element (Argon) The Periodic Table of Elements Next Element (Calcium) Calcium Isotopes of the Element Potassium [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 39 93.2581% STABLE 40 0.0117% 1.248×10+9 years 41 6.7302% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 32 No Data Available Proton Emission (suspected) No Data Available 33 < 25 nanoseconds Proton Emission No Data Available 34 < 25 nanoseconds Proton Emission No Data Available 35 178 milliseconds Electron Capture 100.00% Electron Capture with delayed Proton Emission 0.37% 36 342 milliseconds Electron Capture 100.00%

397

It's Elemental - Isotopes of the Element Phosphorus  

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

Silicon Silicon Previous Element (Silicon) The Periodic Table of Elements Next Element (Sulfur) Sulfur Isotopes of the Element Phosphorus [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 31 100% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 24 No Data Available Electron Capture (suspected) No Data Available Proton Emission (suspected) No Data Available 25 < 30 nanoseconds Proton Emission 100.00% 26 43.7 milliseconds Electron Capture 100.00% Electron Capture with delayed Proton Emission No Data Available 27 260 milliseconds Electron Capture 100.00% Electron Capture with

398

It's Elemental - Isotopes of the Element Gallium  

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

Zinc Zinc Previous Element (Zinc) The Periodic Table of Elements Next Element (Germanium) Germanium Isotopes of the Element Gallium [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 69 60.108% STABLE 71 39.892% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 56 No Data Available Proton Emission (suspected) No Data Available 57 No Data Available Proton Emission (suspected) No Data Available 58 No Data Available Proton Emission (suspected) No Data Available 59 No Data Available Proton Emission (suspected) No Data Available 60 70 milliseconds Electron Capture 98.40%

399

It's Elemental - Isotopes of the Element Sodium  

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

Neon Neon Previous Element (Neon) The Periodic Table of Elements Next Element (Magnesium) Magnesium Isotopes of the Element Sodium [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 23 100% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 18 1.3×10-21 seconds Proton Emission 100.00% 19 < 40 nanoseconds Proton Emission No Data Available 20 447.9 milliseconds Electron Capture with delayed Alpha Decay 20.05% Electron Capture 100.00% 21 22.49 seconds Electron Capture 100.00% 22 2.6027 years Electron Capture 100.00% 23 STABLE - - 24 14.997 hours Beta-minus Decay 100.00%

400

It's Elemental - Isotopes of the Element Neon  

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

Fluorine Fluorine Previous Element (Fluorine) The Periodic Table of Elements Next Element (Sodium) Sodium Isotopes of the Element Neon [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 20 90.48% STABLE 21 0.27% STABLE 22 9.25% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 16 9×10-21 seconds Double Proton Emission 100.00% 17 109.2 milliseconds Electron Capture with delayed Alpha Decay No Data Available Electron Capture 100.00% Electron Capture with delayed Proton Emission 100.00% 18 1.6670 seconds Electron Capture 100.00% 19 17.22 seconds Electron Capture 100.00% 20 STABLE - -

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

It's Elemental - Isotopes of the Element Copper  

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

Nickel Nickel Previous Element (Nickel) The Periodic Table of Elements Next Element (Zinc) Zinc Isotopes of the Element Copper [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 63 69.15% STABLE 65 30.85% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 52 No Data Available Proton Emission No Data Available 53 < 300 nanoseconds Electron Capture No Data Available Proton Emission No Data Available 54 < 75 nanoseconds Proton Emission No Data Available 55 27 milliseconds Electron Capture 100.00% Electron Capture with delayed Proton Emission 15.0% 56 93 milliseconds Electron Capture 100.00%

402

It's Elemental - Isotopes of the Element Boron  

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

Beryllium Beryllium Previous Element (Beryllium) The Periodic Table of Elements Next Element (Carbon) Carbon Isotopes of the Element Boron [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 10 19.9% STABLE 11 80.1% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 6 No Data Available Double Proton Emission (suspected) No Data Available 7 3.255×10-22 seconds Proton Emission No Data Available Alpha Decay No Data Available 8 770 milliseconds Electron Capture 100.00% Electron Capture with delayed Alpha Decay 100.00% 9 8.439×10-19 seconds Proton Emission 100.00% Double Alpha Decay 100.00%

403

It's Elemental - Isotopes of the Element Tungsten  

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

Tantalum Tantalum Previous Element (Tantalum) The Periodic Table of Elements Next Element (Rhenium) Rhenium Isotopes of the Element Tungsten [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 180 0.12% >= 6.6×10+17 years 182 26.50% STABLE 183 14.31% > 1.3×10+19 years 184 30.64% STABLE 186 28.43% > 2.3×10+19 years Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 157 275 milliseconds Electron Capture No Data Available 158 1.25 milliseconds Alpha Decay 100.00% 158m 0.143 milliseconds Isomeric Transition No Data Available Alpha Decay No Data Available 159 7.3 milliseconds Alpha Decay ~ 99.90%

404

It's Elemental - Isotopes of the Element Carbon  

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

Boron Boron Previous Element (Boron) The Periodic Table of Elements Next Element (Nitrogen) Nitrogen Isotopes of the Element Carbon [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 12 98.93% STABLE 13 1.07% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 8 1.981×10-21 seconds Proton Emission 100.00% Alpha Decay No Data Available 9 126.5 milliseconds Electron Capture 100.00% Electron Capture with delayed Proton Emission 61.60% Electron Capture with delayed Alpha Decay 38.40% 10 19.308 seconds Electron Capture 100.00% 11 20.334 minutes Electron Capture 100.00% 12 STABLE - -

405

It's Elemental - Isotopes of the Element Rhenium  

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

Tungsten Tungsten Previous Element (Tungsten) The Periodic Table of Elements Next Element (Osmium) Osmium Isotopes of the Element Rhenium [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 185 37.40% STABLE 187 62.60% 4.33×10+10 years Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 159 No Data Available No Data Available No Data Available 160 0.82 milliseconds Proton Emission 91.00% Alpha Decay 9.00% 161 0.44 milliseconds Proton Emission 100.00% Alpha Decay <= 1.40% 161m 14.7 milliseconds Alpha Decay 93.00% Proton Emission 7.00% 162 107 milliseconds Alpha Decay 94.00% Electron Capture 6.00%

406

Isotope ratio determination in boron analysis  

Science Journals Connector (OSTI)

Traditionally, boron (B) isotope ratios have been determined using thermal ionization...+, Cs+, or O-...for analyte ionization. TIMS can be used in negative or positive ion modes with high sensitivity and precisi...

Ram N. Sah; Patrick H. Brown

1998-12-01T23:59:59.000Z

407

Magnetic moments of long isotopic chains  

E-Print Network [OSTI]

Dipole magnetic moments of several long isotopic chains are analyzed within the self-consistent Finite Fermi System theory based on the Generalized Energy Density Functional method with exact account for the pairing and quasi-particle continuum. New data for nuclei far from the beta-stability valley are included in the analysis. For a number of semi-magic isotopes of the tin and lead chains a good description of the data is obtained, with accuracy of 0.1 - 0.2 mu_N. A chain of non-magic isotopes of copper is also analyzed in detail. It is found that the systematic analysis of magnetic moments of this long chain yields rich information on the evolution of the nuclear structure of the Cu isotopes. In particular, it may give a signal of deformation for the ground state of some nuclei in the chain.

I. N. Borzov; E. E. Saperstein; S. V. Tolokonnikov; G. Neyens; N. Severijns

2008-04-28T23:59:59.000Z

408

ICE CORE RECORDS | Greenland Stable Isotopes  

Science Journals Connector (OSTI)

Abstract Greenland ice cores contain a wealth of information on past climatic conditions throughout the Northern Hemisphere. A historical perspective on the climatic interpretation of stable isotopes in water and ice is presented in the introduction, while the remainder of the article is devoted to the current interpretation of stable isotope data from Greenland ice cores. The progress in our understanding of stable isotope signals, on timescales from seasons to glacial cycles, is discussed and evaluated through numerous examples from Greenland ice cores. Stable isotope profiles from the Camp Century, Dye-3, GISP2, GRIP, NGRIP, and Renland deep ice cores are emphasized, as they all provide climatic information dating back into the Eemian period.

B.M. Vinther; S.J. Johnsen

2013-01-01T23:59:59.000Z

409

Nuclear Astrophysics in Rare Isotope Facilities  

E-Print Network [OSTI]

Nuclear reactions in stars are difficult to measure directly in the laboratory at the small astrophysical energies. In recent years indirect methods with rare isotopes have been developed and applied to extract low-energy astrophysical cross sections.

C. A. Bertulani

2009-11-02T23:59:59.000Z

410

Gaseous isotope separation using solar wind phenomena  

Science Journals Connector (OSTI)

...isotope separation using solar wind phenomena Chia-Gee...essentially the same as that of the solar wind propagation, in which...the author was measuring solar wind parameters under Dr. H. S. Bridge at Massachusetts Institute of Technology in...

Chia-Gee Wang

1980-01-01T23:59:59.000Z

411

NONRADIOGENIC ISOTOPES IN GEOLOGY: A REVIEW  

Science Journals Connector (OSTI)

...has revised Brown's figures. Seaborg and Pearlman (1948) and more recently...51, p. 263-300. and Jenks, Glenn (1944) Isotopic composition of...Science,vol. 79, p. 565. Seaborg, Glenn T., and Pearlman, I. (1948...

412

Storage of Hydrogen Isotopes in Uranium Alloys  

Science Journals Connector (OSTI)

Tritium Properties and Interactions with Material / Proceedings of the Third Topical Meeting on Tritium Technology in Fission, Fusion and Isotopic Applications (Toronto, Ontario, Canada, May 1-6, 1988)

T. Yamamoto; Supardjo; T. Terai; F. Ono; S. Tanaka; M. Yamawaki

413

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

414

Isotope/element fractionation during surface adsorption  

Science Journals Connector (OSTI)

The adsorption of ions onto mineral surfaces accompanies isotope/element fractionation in planets and asteroids. A model based on simple classical physics is presented to predict these fractionations. The agreement between the experimentally observed isotope/element ratios and their predicted values is found to be excellent. This fractionation can be demonstrated experimentally in advanced physics laboratories using macroscopic particles. The success of the model shows students that even a very complex naturally occurring process can be explained quantitatively with simple physics.

Gamini Seneviratne; Asiri Nanayakkara

2004-01-01T23:59:59.000Z

415

Manifestation and Origin of the Isotope Effect  

E-Print Network [OSTI]

This article reviews from one point of view the current status of the manifestations of isotope effect in a nuclear, atomic and molecular as well as solid state physics. Although these manifestations vary, they have one common feature - they all depend on mass. At present time the Standard Model can't explain the origin of the mass of elementary particles and their hierarchy. The last one don't permit to find the origin of the isotope effect.

V. G. Plekhanov

2009-07-12T23:59:59.000Z

416

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

417

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

418

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...

419

Natural Ores as Oxygen Carriers in Chemical Looping Combustion  

Science Journals Connector (OSTI)

Natural Ores as Oxygen Carriers in Chemical Looping Combustion ... Chemical looping combustion (CLC) is a combustion technology that utilizes oxygen from oxygen carriers (OC), such as metal oxides, instead of air to combust fuels. ...

Hanjing Tian; Ranjani Siriwardane; Thomas Simonyi; James Poston

2013-01-02T23:59:59.000Z

420

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

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

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

422

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...

423

E-Print Network 3.0 - abundance isotopic Sample Search Results  

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

Search Sample search results for: abundance isotopic Page: << < 1 2 3 4 5 > >> 1 ISOTOPE FRACTIONATION Isotopes are atoms whose nuclei contain the same number of protons but...

424

E-Print Network 3.0 - alpha-deuterium isotope effects Sample...  

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

deuterium isotope effects Search Powered by Explorit Topic List Advanced Search Sample search results for: alpha-deuterium isotope effects Page: << < 1 2 3 4 5 > >> 1 ISOTOPE...

425

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.

426

Isotope Program Facilities | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

include the High Flux Isotope Reactor at Oak Ridge National Laboratory and the Advanced Test Reactor at Idaho National Laboratory. The DOE Isotope Program also supports isotope...

427

E-Print Network 3.0 - applied isotope techniques Sample Search...  

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

Sciences and Ecology ; Biology and Medicine 100 Electrochemical Isotope Effect and Lithium Isotope Separation Jay R. Black, Summary: that the magnitude of isotopic...

428

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

429

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

430

The Northwest Geysers High-Temperature Reservoir- Evidence For Active  

Open Energy Info (EERE)

Geysers High-Temperature Reservoir- Evidence For Active Geysers High-Temperature Reservoir- Evidence For Active Magmatic Degassing And Implications For The Origin Of The Geysers Geothermal Field Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: The Northwest Geysers High-Temperature Reservoir- Evidence For Active Magmatic Degassing And Implications For The Origin Of The Geysers Geothermal Field Details Activities (2) Areas (1) Regions (0) Abstract: Noble gas isotope abundances in steam from the Coldwater Creek field of the Northwest Geysers, California, show mixing between a nearly pure mid-ocean ridge (MOR) type magmatic gas with high 3He/4He and low radiogenic 40*Ar (R/Ra > 8.3 and 40*Ar/4He < 0.07), and a magmatic gas diluted with crustal gas (R/Ra 0.25). The

431

Final Report, NEAC Subcommittee for Isotope Research & Production Planning  

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

Final Report, NEAC Subcommittee for Isotope Research & Production Final Report, NEAC Subcommittee for Isotope Research & Production Planning Final Report, NEAC Subcommittee for Isotope Research & Production Planning Isotopes, including both radioactive and stable isotopes, make important contributions to research, medicine, and industry in the United States and throughout the world. For nearly fifty years, the Department of Energy (DOE) has actively promoted the use of isotopes by funding (a) production of isotopes at a number of national laboratories with unique nuclear reactors or particle accelerators, (b) nuclear medicine research at the laboratories and in academia, (c) research into industrial applications of isotopes, and (d) research into isotope production and processing methods. The radio- pharmaceutical and radiopharmacy industries have their origin in

432

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

433

TRIFID (TRansuranic Isotopic Fraction Interrogation Device): A second generation plutonium isotopic analysis system  

SciTech Connect (OSTI)

The TRIFID (Transuranic Isotopic Fraction Interrogation Device) system is a second generation plutonium isotopic analysis system which incorporates many new and unique features in the area of isotopic data acquisition and isotopic analysis instrument consisting of a Canberra Series 95-MCA interfaced to a Compaq 386 computer. The entire TRIFID software package, including MCA communications and isotopic analysis routines, was developed using the C programming language. Extensive use has been made of user friendly screens and menus for ease of operation and training and to facilitate use by technical level operators. Automated TRIFID features provide for MCA/ADC setup and acquisition, spectral storage, isotopic analysis, and report generation. One unique feature of the TRIFID system design allows it to be pre-programed for an entire day's counting. The isotopic analysis module (EPICS) contains an expert system formalism which is used to detect and assay for spectral interferences, and to automatically adjust peak fitting constraints based on spectral intensity variations. A TRIFID system has been in operation in a production laboratory at the Rocky Flats Plant since September 1988. Marked decreases in training and hands-on operation time have been achieved in comparison to the older, preceding isotopic systems. 2 refs., 3 figs.

Fleissner, J G; Coressel, T W; Freier, D A; Macklin, L L

1989-01-01T23:59:59.000Z

434

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....

435

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...

436

Oxygen Carriers for Solid Fuel Chemical Looping Combustion Process...  

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

Oxygen Carriers for Solid Fuel Chemical Looping Combustion Process Regenerable Mixed Copper-Iron-Inert Support Oxygen Carriers National Energy Technology Laboratory Contact NETL...

437

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...

438

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 &...

439

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...

440

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...

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

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)...

442

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...

443

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...

444

Oxygen Transport Studies in Nanocrystalline Ceria Films. | EMSL  

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

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

445

Lattice Distortions and Oxygen Vacancies Produced in Au+-Irradiated...  

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

Lattice Distortions and Oxygen Vacancies Produced in Au+-Irradiated Nanocrystalline Cubic Zirconia. Lattice Distortions and Oxygen Vacancies Produced in Au+-Irradiated...

446

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...

447

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...

448

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...

449

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...

450

LED–LED portable oxygen gas sensor  

Science Journals Connector (OSTI)

A portable instrument for oxygen determination, based on the quenching of phosphorescent octaethylporphyrin by gaseous O2..., has been developed using the fluorimetric paired emitter–detector diode technique (FPE...

I. M. Perez de Vargas-Sansalvador; C. Fay…

2012-12-01T23:59:59.000Z

451

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

452

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

453

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

454

Interactions of oxygen with Zr(0001)  

SciTech Connect (OSTI)

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

Flinn, B.J.

1992-01-01T23:59:59.000Z

455

Oxy-combustion: Oxygen Transport Membrane Development  

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

combustion: Oxygen Transport combustion: Oxygen Transport Membrane Development Background The mission of the U.S. Department of Energy's (DOE) Existing Plants, Emissions & Capture (EPEC) Research & Development (R&D) Program is to develop innovative environmental control technologies to enable full use of the nation's vast coal reserves, while at the same time allowing the current fleet of coal-fired power plants to comply with existing and emerging environmental regulations. The EPEC R&D

456

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

457

Underground coal gasification using oxygen and steam  

SciTech Connect (OSTI)

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

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

2009-07-01T23:59:59.000Z

458

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

459

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

460

Isotope Effects on the Enzymatic and Nonenzymatic Reactions of Chorismate  

Science Journals Connector (OSTI)

The isotopic composition of the latter was determined by isotope ratio mass spectrometry, enabling determination of isotope effects at the mechanistically interesting key positions O7, C1, and C9. ... Heavy atom isotope effects on the nonenzymatic Claisen rearrangement to give prephenate, 18k1 and 13k1, were determined at 60 °C as described for the enzymatic reactions and calculated from the following relationship: where xk1 is the apparent isotope effect, expressed as a ratio of the rate constants for the light and heavy (x) isotopes. ...

S. Kirk Wright; Michael S. DeClue; Ajay Mandal; Lac Lee; Olaf Wiest; W. Wallace Cleland; Donald Hilvert

2005-08-27T23:59:59.000Z

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

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

462

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

463

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

464

Isotopic Analysis At Geysers Area (Kennedy & Truesdell, 1996) | Open Energy  

Open Energy Info (EERE)

Geysers Area (Kennedy & Truesdell, 1996) Geysers Area (Kennedy & Truesdell, 1996) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Geysers Area (Kennedy & Truesdell, 1996) Exploration Activity Details Location Geysers Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness could be useful with more improvements DOE-funding Unknown Notes The evidence provided by the noble gases for a magmatic gas component in the Northwest Geysers adds new constraints to genetic models of the system and its evolution. The high proportion of magmatic gas and high total NCG in HTR steam are inconsistent with an origin of the vapor-dominated Northwest Geysers reservoir from deep boiling of a connate or metamorphic water. Instead, the strong magmatic component suggests that the HTR and the

465

ALS Evidence Confirms Combustion Theory  

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

are produced, generally, when insufficient oxygen or other factors result in incomplete combustion of organic matter (e.g., in engines and incinerators, when biomass burns in...

466

Isotope Shift Measurements of Stable and Short-Lived Lithium Isotopes for Nuclear Charge Radii Determination  

E-Print Network [OSTI]

Changes in the mean-square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a new laser spectroscopic approach to determine the charge radii of lithium isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8 ms lifetime isotope with production rates on the order of only 10,000 atoms/s. The method was applied to all bound isotopes of lithium including the two-neutron halo isotope Li-11 at the on-line isotope separators at GSI, Darmstadt, Germany and at TRIUMF, Vancouver, Canada. We describe the laser spectroscopic method in detail, present updated and improved values from theory and experiment, and discuss the results.

W. Nörtershäuser; R. Sánchez; G. Ewald; A. Dax; J. Behr; P. Bricault; B. A. Bushaw; J. Dilling; M. Dombsky; G. W. F. Drake; S. Götte; H. -J. Kluge; Th. Kühl; J. Lassen; C. D. P. Levy; K. Pachucki; M. Pearson; M. Puchalski; A. Wojtaszek; Z. -C. Yan; C. Zimmermann

2010-09-02T23:59:59.000Z

467

REPORT OF SURVEY OF OAK RIDGE ISOTOPE  

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

OAK RIDGE ISOTOPE OAK RIDGE ISOTOPE ENRICHMENT (CALUTRON) FACILITY BUILDING 9204-3 U.S. Department of Energy Office of Environmental Management & Office of Nuclear Energy Report of Survey of Oak Ridge Isotope Enrichment (Calutron) Facility Building 9204-3 FINAL May 8, 2000 Contents 1. Introduction 1.1 Purpose 1.2 Facility Description 1.3 Organization Representatives 1.4 Survey Participants 2. Summary, Conclusions & Recommendations 2.1 Transfer Considerations 2.2 Post-Transfer EM Path Forward & Management Risk 3. Survey Results 4. Stabilization and Other Actions Required for Transfer 5. Surveillance & Maintenance After Transfer 6. Other Transfer Details 7. Attachments and References Appendix A - Detailed Survey Notes

468

Isotopic substitution in a model polaronic system  

Science Journals Connector (OSTI)

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

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

1999-04-01T23:59:59.000Z

469

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

470

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

471

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

472

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

473

Mass-Spectrometric Measurement of Lithium, Beryllium, and Boron Isotopes Produced in O16 by High-Energy Protons, and Some Astrophysical Implications  

Science Journals Connector (OSTI)

A special mass-spectrometric method has been developed to determine the isotopic ratios and isotopic absolute cross sections of Li, Be, and B, formed by spallation of oxygen irradiated by protons of energy 135, 550, and 19 GeV. A brief description is given of the ion source of the mass spectrometer—of an ion sputtering type—which permits a very efficient ionization of beryllium and boron. The performances are given; they allow the analysis of 10-12 to 10-13 g of these elements. The oxygen target is made of very high purity water, and special handling techniques have been worked out to reduce contamination to an acceptable level. The determination of each of the isotopic ratios Li7/Li6, Be9/Be7, Be10/Be9, and B11/B10 requires a specific method, which is described. Isotope dilution techniques are used to obtain the absolute cross sections; values in millibarns for 135-MeV protons are as follows: Li6:10±2, Li7:8.0±2.5, Be9:1.7±0.5, Be10:0.35±0.20, B10:11±3, and B11:25±8. There are no significant changes at the higher energies. The above cross sections give support to conclusions based previously on calculated values concerning the spallation origin of Li, Be, and B in the solar system, in stars, and in the cosmic radiation.

F. Yiou; M. Baril; J. Dufaure de Citres; P. Fontes; E. Gradsztajn; R. Bernas

1968-02-20T23:59:59.000Z

474

Report of Survey of Oak Ridge Isotope Enrichment (Calutron) Facility...  

Office of Environmental Management (EM)

Report of Survey of Oak Ridge Isotope Enrichment (Calutron) Facility Building 9204-3 Report of Survey of Oak Ridge Isotope Enrichment (Calutron) Facility Building 9204-3 The...

475

Isotope effects in methanol synthesis and the reactivity of copper...  

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

Isotope effects in methanol synthesis and the reactivity of copper formates on a CuSiO2 catalyst. Isotope effects in methanol synthesis and the reactivity of copper formates on a...

476

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

Open Energy Info (EERE)

gas abundances and isotopic compositions. The helium isotopic compositions of fluids produced from the Dixie Valley geothermal field range from 0.70 to 0.76 Ra, are among the...

477

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

478

Absorption process for producing oxygen and nitrogen and solution therefor  

DOE Patents [OSTI]

Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible. 1 figure

Roman, I.C.; Baker, R.W.

1990-09-25T23:59:59.000Z

479

Absorption process for producing oxygen and nitrogen and solution therefor  

DOE Patents [OSTI]

Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible.

Roman, Ian C. [Wilmington, DE; Baker, Richard W. [Palo Alto, CA

1990-09-25T23:59:59.000Z

480

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

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

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

482

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

483

A View of Antarctic Ice-Sheet Evolution from Sea-Level and Deep-Sea Isotope Changes During the Late Cretaceous-Cenozoic  

E-Print Network [OSTI]

sheet in the earliest Oligocene (33.55 Ma), but there is physical evidence for glaciation in the Eocene. Though there are inherent limitations in sea-level and deep-sea isotope records, both place constraints on the size and extent of Late Cretaceous...

Miller, K. G.; Wright, J. D.; Katz, M. E.; Browning, J. V.; Cramer, B. S.; Wade, Bridget S.; Mizintseva, S. F.

2008-01-01T23:59:59.000Z

484

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

485

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

486

On the solar nickel and oxygen abundances  

E-Print Network [OSTI]

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

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

2008-11-05T23:59:59.000Z

487

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

488

Oxygen Hydration Mechanism for the Oxygen Reduction Reaction at Pt and Pd Fuel Cell Catalysts  

Science Journals Connector (OSTI)

Oxygen Hydration Mechanism for the Oxygen Reduction Reaction at Pt and Pd Fuel Cell Catalysts ... Catalytic Reactions on the Open-Edge Sites of Nitrogen-Doped Carbon Nanotubes as Cathode Catalyst for Hydrogen Fuel Cells ... Despite significant progress made the past decade on reducing the platinum catalyst loading in the PEMFC electrodes, further ... ...

Yao Sha; Ted H. Yu; Boris V. Merinov; Pezhman Shirvanian; William A. Goddard; III

2011-02-24T23:59:59.000Z

489

Equilibrium Isotope Effect for Hydrogen Absorption in Palladium  

Science Journals Connector (OSTI)

The method using addition of isotopes to the system in sequence to investigate isotope exchange effects has not been previously reported. ... (1) A simple model was proposed(1) that described the dependence of the desorption plateau pressure on a linear combination of the isotopic fractions in the solid and the plateau pressures of the single-isotope?Pd systems; that is, H?Pd and D?Pd. ...

Weifang Luo; Donald F. Cowgill; Rion A. Causey

2009-10-21T23:59:59.000Z

490

Isotopic Enrichment of Tritiated Water by a Bipolar Electrolysis Process  

Science Journals Connector (OSTI)

Isotope Separation / Proceedings of the Sixth International Conference on Tritium Science and Technology Tsukuba, Japan November 12-16, 2001

S. Heinze; D. Ducret; J.-P. Verdin; T. Pelletier

491

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...

492

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

493

Final Report on Isotope Ratio Techniques for Light Water Reactors  

SciTech Connect (OSTI)

The Isotope Ratio Method (IRM) is a technique for estimating the energy or plutonium production in a fission reactor by measuring isotope ratios in non-fuel reactor components. The isotope ratios in these components can then be directly related to the cumulative energy production with standard reactor modeling methods.

Gerlach, David C.; Gesh, Christopher J.; Hurley, David E.; Mitchell, Mark R.; Meriwether, George H.; Reid, Bruce D.

2009-07-01T23:59:59.000Z

494

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

495

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

496

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

497

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

498

Isotope Explorer Users Manual S.Y.F. Chu*  

E-Print Network [OSTI]

Transfer B. Data from Local Disk or the Table of Isotopes CD-ROM C. Isotope Explorer as Helper Application disk (e.g. from the Table of Isotopes CD-ROM). The ENSDF database on the 1999 update CD-ROM

499

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

500

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