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1

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

Open Energy Info (EERE)

Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal System Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal System Details Activities (3) Areas (1) Regions (0) Abstract: Fluids from springs, fumaroles, and wells throughout Dixie Valley, NV were analyzed for noble 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 highest values in the valley, and indicate that similar to 7.5% of the total helium is derived from the mantle. A lack of recent volcanics or other potential sources requires flow of mantle-derived helium up along the

2

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...

3

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

Open Energy Info (EERE)

Pathways 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...

4

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

Open Energy Info (EERE)

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

5

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

6

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

7

Helium isotopes in geothermal systems- Iceland, The Geysers, Raft River and  

Open Energy Info (EERE)

Helium isotopes in geothermal systems- Iceland, The Geysers, Raft River and Helium isotopes in geothermal systems- Iceland, The Geysers, Raft River and Steamboat Springs Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Helium isotopes in geothermal systems- Iceland, The Geysers, Raft River and Steamboat Springs Details Activities (3) Areas (3) Regions (0) Abstract: Helium isotope ratios have been measured in geothermal fluids from Iceland, The Geysers, Raft River, Steamboat Springs and Hawaii. These ratios have been interpreted in terms of the processes which supply He in distinct isotopic ratios (i.e. magmatic He, ~10 Ra; atmospheric He, R,sub>a; and crustal He, ~0.1 Ra) and in terms of the processes which can alter the isotopic ratio (hydrologic mixing, U-Th series alpha production and weathering release of crustal He, magma aging and

8

Helium Isotopes In Geothermal And Volcanic Gases Of The Western United  

Open Energy Info (EERE)

Helium Isotopes In Geothermal And Volcanic Gases Of The Western United Helium Isotopes In Geothermal And Volcanic Gases Of The Western United States, I, Regional Variability And Magmatic Origin Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Helium Isotopes In Geothermal And Volcanic Gases Of The Western United States, I, Regional Variability And Magmatic Origin Details Activities (1) Areas (1) Regions (0) Abstract: Helium isotope ratios in gases of thirty hot springs and geothermal wells and of five natural gas wells in the western United States show no relationship to regional conductive heat flow, but do show a correlation with magma-based thermal activity and reservoir fluid temperature (or total convective heat discharge). Gases from high-T (> 200°C) reservoirs have 3He/4He > 2 _ the atmospheric value, with high He

9

Helium generation rates in isotopically tailored Fe-Cr-Ni alloys irradiated in FFTF/MOTA  

SciTech Connect

Three Fe-Cr-Ni alloys have been doped with 0.4% {sup 59}Ni for side-by-side irradiations of doped and undoped materials in order to determine the effects of fusion-relevant levels of helium production on microstructural development and mechanical properties. The alloys were irradiated in three successive cycles of the Materials Open Test Assembly (MOTA) located in the Fast Flux Test Facility (FFTF). Following irradiation, helium levels were measured by isotope dilution mass spectrometry. The highest level of helium achieved in doped alloys was 172 appm at 9.1 dpa for a helium(appm)-to-dpa ratio of 18.9. The overall pattern of predicted helium generation rates in doped and undoped alloys is in good agreement with the helium measurements.

Greenwood, L.R.; Garner, F.A. [Pacific Northwest Lab., Richland, WA (United States); Oliver, B.M. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.

1991-11-01T23:59:59.000Z

10

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

SciTech Connect

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

Dobson, Patrick

2013-02-11T23:59:59.000Z

11

Flow Of Mantle Fluids Through The Ductile Lower Crust- Helium Isotope  

Open Energy Info (EERE)

Of Mantle Fluids Through The Ductile Lower Crust- Helium Isotope Of Mantle Fluids Through The Ductile Lower Crust- Helium Isotope Trends Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Flow Of Mantle Fluids Through The Ductile Lower Crust- Helium Isotope Trends Details Activities (5) Areas (5) Regions (0) Abstract: Heat and mass are injected into the shallow crust when mantle fluids are able to flow through the ductile lower crust. Minimum He-3/He-4 ratios in surface fluids from the northern Basin and Range Province, western North America, increase systematically from low crustal values in the east to high mantle values in the west, a regional trend that correlates with the rates of active crustal deformation. The highest ratios occur where the extension and shear strain rates are greatest. The

12

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

13

Upper-mantle dynamics revealed by helium isotope variations along the southeast Indian ridge  

Science Journals Connector (OSTI)

... present helium isotope data for MORB glasses recovered along ?5,800?km of the southeast Indian ridge, and develop an approach to quantitatively relate spatial variations in geochemical and geophysical ... quantitatively relate spatial variations in geochemical and geophysical parameters at the Earth's surface. A point-to- ...

D. W. Graham; J. E. Lupton; F. J. Spera; D. M. Christie

2001-02-08T23:59:59.000Z

14

A systematic regional trend in helium isotopes across the northernbasin and range province, Western North America  

SciTech Connect

An extensive study of helium isotopes in fluids collectedfrom surface springs, fumaroles and wells across the northern Basin andRange Province reveals a systematic trend of decreasing 3He/4He ratiosfrom west to east. The western margin of the Basin and Range ischaracterized by mantle-like ratios (6-8 Ra) associated with active orrecently active crustal magma systems (e.g., Coso, Long Valley,Steamboat, and the Cascade volcanic complex). Moving towards the east,the ratios decline systematically to a background value of ~;0.1 Ra. Theregional trend is consistent with extensive mantle melting concentratedalong the western margin and is coincident with an east-to-west increasein the magnitude of northwest strain. The increase in shear strainenhances crustal permeability resulting in high vertical fluid flow ratesthat preserve the high helium isotope ratios at the surface. Superimposedon the regional trend are "helium spikes," local anomalies in the heliumisotope composition. These "spikes" reflect either local zones of mantlemelting or locally enhanced crustal permeability. In the case of theDixie Valley hydrothermal system, it appears to be a combination ofboth.

Kennedy, B. Mack; van Soest, Matthijs C.

2006-05-01T23:59:59.000Z

15

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

DOE Data Explorer (OSTI)

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

Dobson, Patrick

16

Nitrogen cycle of the Baltic Sea from an isotopic perspective Baltic Sea Research Institute-Warnemunde (IOW), Rostock, Germany  

E-Print Network (OSTI)

Nitrogen cycle of the Baltic Sea from an isotopic perspective M. Voss Baltic Sea Research Institute-Warnemu¨nde, Hamburg, Germany S. Hille, T. Neumann, and J. W. Dippner Baltic Sea Research Institute-Warnemu¨nde (IOW

Dippner, Joachim W.

17

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...

18

unstable isotope  

Science Journals Connector (OSTI)

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

2014-08-01T23:59:59.000Z

19

Hydrogen and helium entrapment in flowing liquid metal plasma-facing surfaces  

E-Print Network (OSTI)

Hydrogen and helium entrapment in flowing liquid metal plasma-facing surfaces Ahmed Hassanein the PFC surface (helium and hydrogen isotopes) while accommodating high heat loads. To study this problem. Hydrogen isotope (DT) particles are likely be trapped in the liquid metal surface (e.g., lithium) due

Harilal, S. S.

20

Isotopic Analysis At Northern Basin & Range Region (Kennedy ...  

Open Energy Info (EERE)

useful regional reconnaissance DOE-funding Unknown Notes The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced...

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

Isotopic Analysis At Nw Basin & Range Region (Kennedy & Van Soest...  

Open Energy Info (EERE)

useful regional reconnaissance DOE-funding Unknown Notes The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced...

22

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

Open Energy Info (EERE)

useful regional reconnaissance DOE-funding Unknown Notes The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced...

23

Helium Ion Microscope | EMSL  

NLE Websites -- All DOE Office Websites (Extended Search)

other characterization capabilities. User Portal Name: Helium Ion Microscope Instrument ID: 34104 Availability: 10 hours a day, 5 days a week Facility: Quiet Wing Quick Specs...

24

Evolution of the geothermal fluids at Los Azufres, Mexico, as traced by noble gas isotopes, 18  

E-Print Network (OSTI)

Evolution of the geothermal fluids at Los Azufres, Mexico, as traced by noble gas isotopes, 18 O, D: Noble gases Strontium isotopes Helium isotopes Geothermal energy Los Azufres Araró Mexico Isotopes of noble gases, CO2, H2O and Sr were measured in 10 geothermal wells and 8 hot springs, fumaroles and mud

Long, Bernard

25

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

Open Energy Info (EERE)

Kennedy at the University of California at Berkeley, CA. Isotopic ratios of helium and CO2 determined for gases sampled at LVEW were 3.66 Ra (3He4He ratio) and -6.4 %o (delta...

26

The Helium Question  

Science Journals Connector (OSTI)

...1976 1977 1978 (%) Kansas 55.34 51.58 48...U.S. naturai gas production, except from Alaska...Cryogenic transmis-sion of electricity, already technically...are so inefficient or site-dependent. Superconductivity...to supplement its own production with heli-um purchased...

Earl Cook

1979-12-07T23:59:59.000Z

27

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

Open Energy Info (EERE)

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

28

Effective Helium Burning Rates and the Production of the Neutrino Nuclei  

E-Print Network (OSTI)

Effective values for the key helium burning reaction rates, triple-alpha and 12C(alpha,gamma)16O, are obtained by adjusting their strengths so as to obtain the best match with the solar abundance pattern of isotopes uniquely or predominately made in core collapse supernovae. These effective rates are then used to determine the production of the neutrino isotopes. The use of effective rates considerably reduces the uncertainties in the production factors arising from uncertainties in the helium burning rates, and improves our ability to use the production of 11B to constrain the neutrino emission from supernovae.

Sam M. Austin; Christopher West; Alexander Heger

2014-02-26T23:59:59.000Z

29

Effective Helium Burning Rates and the Production of the Neutrino Nuclei  

E-Print Network (OSTI)

Effective values for the key helium burning reaction rates, triple-alpha and 12C(alpha,gamma)16O, are obtained by adjusting their strengths so as to obtain the best match with the solar abundance pattern of isotopes uniquely or predominately made in core collapse supernovae. These effective rates are then used to determine the production of the neutrino isotopes. The use of effective rates considerably reduces the uncertainties in the production factors arising from uncertainties in the helium burning rates, and improves our ability to use the production of 11B to constrain the neutrino emission from supernovae.

Austin, Sam M; Heger, Alexander

2014-01-01T23:59:59.000Z

30

Isotopic Analysis At U.S. West Region (Welhan, Et Al., 1988) | Open Energy  

Open Energy Info (EERE)

U.S. West Region (Welhan, Et Al., 1988) U.S. West Region (Welhan, Et Al., 1988) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At U.S. West Region (Welhan, Et Al., 1988) Exploration Activity Details Location U.S. West Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful DOE-funding Unknown Notes Helium isotope ratios are not correlated with regional heat flow in the western United States. High helium isotope ratios (R/RA > 2) occur only in magma-based geothermal systems. A direct correlation exists between geothermal reservoir temperature and helium isotope ratio of the fluids, suggesting that both heat and helium in a geothermal reservoir are derived from a shallow magmatic source. The rapid lateral decrease in 3He away from

31

Helium dilution refrigeration system  

DOE Patents (OSTI)

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

Roach, Patrick R. (Darien, IL); Gray, Kenneth E. (Naperville, IL)

1988-01-01T23:59:59.000Z

32

The Viscosity of Liquid Helium  

Science Journals Connector (OSTI)

2 September 1935 research-article The Viscosity of Liquid Helium J. O. Wilhelm A. D. Misener A. R. Clark The Royal Society is collaborating with JSTOR to digitize, preserve...

1935-01-01T23:59:59.000Z

33

Roughening transition and helium crystals  

Science Journals Connector (OSTI)

Crystal shapes or crystal growth mechanisms depend drastically on whether the crystal surface is smooth or rough, i.e. whether the temperature is lower or higher than its roughening temperature. Helium appeared r...

S. Balibar; F. Gallet; E. Rolley; P. E. Wolf

1985-01-01T23:59:59.000Z

34

Liquid helium cryo TEM | EMSL  

NLE Websites -- All DOE Office Websites (Extended Search)

cryo TEM Liquid helium cryo TEM The JEOL JEM-3000SFF was designed for high-resolution cryogenic transmission electron microscopy (cryo-EM) of biological samples and expands EMSL...

35

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

36

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

Open Energy Info (EERE)

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

37

Carbon Isotopes  

NLE Websites -- All DOE Office Websites (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)

38

Electric Dipole Polarizabilities of Hydrogen and Helium Isotopes  

E-Print Network (OSTI)

The electric dipole polarizabilities of $^3$H, $^3$He, and $^4$He are calculated directly using the Schr\\"odinger equation with the latest generation of two- and three-nucleon interactions. These polarizabilities are necessary in order to obtain accurate nuclear-polarization corrections for transitions involving S-waves in one- and two-electron atoms. Our results are compared to previous results, and it is shown that direct calculations of the electric polarizability of $^4$He using modern nuclear potentials are smaller than published values calculated using experimental photoabsorption data. The status of this topic is assessed in the context of precise measurements of transitions in one- and two-electron atoms.

I. Stetcu; S. Quaglioni; J. L. Friar; A. C. Hayes; P. Navrátil

2009-04-23T23:59:59.000Z

39

Helium isotopes in geothermal systems- Iceland, The Geysers,...  

Open Energy Info (EERE)

MOR type magmatic He again implying an active volcanic source possibly a "leaky" transform related to the San Andreas Fault System. Raft River contains only crustal He...

40

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

Open Energy Info (EERE)

Isotopic Analysis At Dixie Valley Geothermal Field Area (Kennedy & Van Isotopic Analysis At Dixie Valley Geothermal Field Area (Kennedy & Van Soest, 2006) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Dixie Valley Geothermal Field Area (Kennedy & Van Soest, 2006) Exploration Activity Details Location Dixie Valley Geothermal Field Area Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful DOE-funding Unknown Notes Fluids from springs, fumaroles, and wells throughout Dixie Valley, NV were analyzed for noble 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 highest values in the valley, and indicate that _7.5% of the total helium is derived from the

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

Isotopic Analysis At Central Nevada Seismic Zone Region (Kennedy & Van  

Open Energy Info (EERE)

Isotopic Analysis At Central Nevada Seismic Zone Region (Kennedy & Van Isotopic Analysis At Central Nevada Seismic Zone Region (Kennedy & Van Soest, 2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Central Nevada Seismic Zone Region (Kennedy & Van Soest, 2007) Exploration Activity Details Location Central Nevada Seismic Zone Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown Notes The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced permeability and that mantle fluids can penetrate the ductile lithosphere, even in regions where there is no substantial magmatism. Superimposed on the regional trend are local,

42

from Isotope Production Facility  

NLE Websites -- All DOE Office Websites (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...

43

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

44

On the Triplets of Helium  

Science Journals Connector (OSTI)

It is well known that the inversion of the helium triplets and their deviation from interval rule are due to the spin-other-orbit and to the magnetic spin-spin interactions (respectively), which may be neglected in comparison with the spin-orbit interaction in treating the spectra of heavy elements. The preliminary calculation of Heisenberg is compared with the correct calculation of Breit for the lowest triplet. The extension to higher triplets, by Araki, is simplified and generalized, and the comparison with experiment is discussed.

D. R. Inglis

1942-03-01T23:59:59.000Z

45

Closed cycle liquid helium refrigerators  

Science Journals Connector (OSTI)

We have developed closed cycle liquid helium refrigerators using a Joule Thomson circuit precooled by commercially available two staged Gifford Mac Mahon cryocoolers. The Joule Thomson counterflow heat exchangers are modular and have been thermo-hydraulically characterized. Fully automatic cool down and operation are achieved by two pneumatically driven by pass and expansion valves. Several apparatus have been built or are under assembly with cooling power ranging from 100 mW up to 5 Watt, for temperature ranging from 2.8 K up to 4.5 K. A trouble free operation with several warm up and cool down cycles has been proven over 7000 hours.

G. Claudet; R. Lagnier; A. Ravex

1992-01-01T23:59:59.000Z

46

Neutron Scattering from Liquid Helium at Large Momentum Transfer  

Science Journals Connector (OSTI)

......letter Letters to the Editor Neutron Scattering from Liquid Helium at Large...Vol. 46 (1971), No. 1 Neutron Scattering from Liquid Helium at Large...Feynman diagram for the elastic scattering of a neutron from liquid helium, where......

Sigenobu Sunakawa; Kazuo Okajima; Kiyohisa Matsuda

1971-07-01T23:59:59.000Z

47

Superfluid helium as a technical coolant  

E-Print Network (OSTI)

The characteristics of superfluid helium as a technical coolant, which derive from its specific transport properties, are presented with particular reference to the working area in the phase diagram (saturated or pressurised helium II). We then review the principles and scaling laws of heat transport by equivalent conduction and by forced convection in pressurised helium II, thus revealing intrinsic limitations as well as technological shortcomings of these cooling methods. Once properly implemented, two-phase flow of saturated helium II presents overwhelming advantages over the previous solutions, which dictated its choice for cooling below 1.9 K the long strings of superconducting magnets in the Large Hadron Collider (LHC), a 26.7 km circumference particle collider now under construction at CERN, the European Laboratory for Particle Physics near Geneva (Switzerland). We report on recent results from the ongoing research and development programme conducted on thermohydraulics of two-phase saturated helium II...

Lebrun, P

1997-01-01T23:59:59.000Z

48

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

49

Isotopic Analysis-Fluid At Steamboat Springs Geothermal Area (1982) | Open  

Open Energy Info (EERE)

Isotopic Analysis-Fluid At Steamboat Springs Geothermal Area (1982) Isotopic Analysis-Fluid At Steamboat Springs Geothermal Area (1982) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis-Fluid At Steamboat Springs Geothermal Area (1982) Exploration Activity Details Location Steamboat Springs Geothermal Area Exploration Technique Isotopic Analysis-Fluid Activity Date 1982 Usefulness not indicated DOE-funding Unknown Notes Helium isotope ratios have been measured in geothermal fluids. These ratios have been interpreted in terms of the processes which supply He in distinct isotopic ratios (i.e. magmatic He, ~10 Ra; atmospheric He, Ra; and crustal He, ~0.1 Ra) and in terms of the processes which can alter the isotopic ratio (hydrologic mixing, U-Th series alpha production and weathering

50

Helium refrigeration considerations for cryomodule design  

SciTech Connect

Many of the present day accelerators are based on superconducting radio frequency (SRF) cavities, packaged in cryo-modules (CM), which depend on helium refrigeration at sub-atmospheric pressures, nominally 2 K. These specialized helium refrigeration systems are quite cost intensive to produce and operate. Particularly as there is typically no work extraction below the 4.5-K supply, it is important that the exergy loss between this temperature level and the CM load temperature(s) be minimized by the process configuration choices. This paper will present, compare and discuss several possible helium distribution process arrangements to support the CM loads.

Ganni, V.; Knudsen, P. [Thomas Jefferson National Accelerator Facility (JLab), Newport News, VA 23606 (United States)

2014-01-29T23:59:59.000Z

51

Phase transitions of helium in aerogel  

Science Journals Connector (OSTI)

The effect of dilute quenched impurities on the liquid-vapor critical point, superfluid and He3?He4 phase separation transitions were studied by introducing liquid helium into aerogel. Aerogel is a highly porous ...

M. H. W. Chan

1996-01-01T23:59:59.000Z

52

NIDC: Online Catalog of Isotope Products | Product List  

NLE Websites -- All DOE Office Websites (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

53

Equation of state of metallic helium  

SciTech Connect

The effective ion-ion interaction, free energy, pressure, and electric resistance of metallic liquid helium have been calculated in wide density and temperature ranges using perturbation theory in the electron-ion interaction potential. In the case of conduction electrons, the exchange interaction has been taken into account in the random-phase approximation and correlations have been taken into account in the local-field approximation. The solid-sphere model has been used for the nuclear subsystem. The diameter of these spheres is the only parameter of this theory. The diameter and density of the system at which the transition of helium from the singly ionized to doubly ionized state occurs have been estimated by analyzing the pair effective interaction between helium atoms. The case of doubly ionized helium atoms has been considered. Terms up to the third order of perturbation theory have been taken into account in the numerical calculations. The contribution of the third-order term is significant in all cases. The electric resistance and its temperature dependence for metallic helium are characteristic of simple divalent metals in the liquid state. The thermodynamic parameters-temperature and pressure densities-are within the ranges characteristic of the central regions of giant planets. This makes it possible to assume the existence of helium in the metallic state within the solar system.

Shvets, V. T., E-mail: tarval@breezein.net [Odessa State Academy of Refrigeration (Ukraine)

2013-01-15T23:59:59.000Z

54

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

55

isotopic ratio | EMSL  

NLE Websites -- All DOE Office Websites (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...

56

ISAC SC-LINAC PHASE-II HELIUM REFRIGERATOR COMMISSIONING AND FIRST OPERATIONAL EXPERIENCE AT TRIUMF  

SciTech Connect

ISAC Phase-II is an upgrade of the radioactive isotope superconducting linear accelerator, SC-linac, at TRIUMF. The Phase-I section of the accelerator, medium-beta, is operational and is cooled with a 600 W helium refrigerator, commissioned in March 2005. An identical refrigerator is being used with the Phase-II segment of the accelerator; which is now under construction. The second refrigerator has been commissioned and tested with the Phase-I section of the linac and is used for Phase-II linac development, including new SC-cavity performance tests. The commissioning of the Phase-II refrigeration system and recent operational experience is presented.

Sekachev, I.; Kishi, D.; Laxdal, R. E. [TRIUMF, Vancouver, BC, V6T 2A3 (Canada)

2010-04-09T23:59:59.000Z

57

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"

58

Isotopic Analysis-Fluid At Raft River Geothermal Area (1982) | Open Energy  

Open Energy Info (EERE)

Analysis-Fluid At Raft River Geothermal Area Analysis-Fluid At Raft River Geothermal Area (1982) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Isotopic Analysis- Fluid Activity Date 1982 Usefulness not useful DOE-funding Unknown Exploration Basis Determine which reservoir model best matches the isotope data. Notes 1) Chemical and light-stable isotope data are presented for water samples from the Raft River geothermal area and nearby. On the basis of chemical character, as defined by a trilinear plot of per cent milliequivalents, and light-stable isotope data, the waters in the geothermal area can be divided into waters that have and have not mixed with cold water. 2) Helium isotope ratios have been measured in geothermal fluids. These ratios have been interpreted in terms of the processes which supply He in distinct isotopic

59

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

60

Stable isotope studies  

SciTech Connect

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

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

Modeling-Computer Simulations At Dixie Valley Geothermal Area...  

Open Energy Info (EERE)

is currently being utilized. References B. M. Kennedy, M. C. van Soest (2006) A Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal System Additional References...

62

Industry Perspective  

Energy.gov (U.S. Department of Energy (DOE))

Fuel cell and biogas industries perspectives. Presented by Mike Hicks, Fuel Cell and Hydrogen Energy Association, at the NREL/DOE Biogas and Fuel Cells Workshop held June 11-13, 2012, in Golden, Colorado.

63

Helium-filled aluminum flight tubes  

NLE Websites -- All DOE Office Websites (Extended Search)

Helium-filled aluminum flight tubes. Helium-filled aluminum flight tubes. Detector housing for the CCD camera lens, mirror, and scintillator. For more information, contact Instrument Scientist: Hassina Bilheux, bilheuxhn@ornl.gov, 865.384.9630 neutrons.ornl.gov/instruments/HFIR/factsheets/Instrument-cg1d.pdf The CG-1D beam is used for neutron imaging measurements using a white beam. Apertures (with different diameters D (pinhole geometry) are used at the entrance of the helium-filled flight path to allow L/D variation from 400 to 800. L is the distance between the aperture and the detector (where the image is produced). Samples sit on a translation/ rotation stage for alignment and tomography purposes. Detectors for CG-1D include

64

Helium corona-assisted air discharge  

SciTech Connect

Operation of atmospheric discharge of electronegative gases including air at low voltages yet without consuming any inert gas will enormously promote the application of non-thermal plasmas. By taking advantage of the low onset voltage for helium corona, air discharge was successfully launched at much reduced voltages with a needle-plate system partly contained in a helium-filled glass bulb--for a needle-plate distance of 12 mm, 1.0 kV suffices. Ultraviolet emission from helium corona facilitates the discharging of air, and the discharge current manifests distinct features such as relatively broad Trichel pulses in both half periods. This design allows safe and economic implementation of atmospheric discharge of electronegative gases, which will find a broad palette of applications in surface modification, plasma medicine and gas treatment, etc.

Jiang Nan; Gao Lei; Ji Ailing; Cao Zexian [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2011-10-15T23:59:59.000Z

65

Isotopic Analysis At Walker-Lane Transitional Zone Region (Kennedy & Van  

Open Energy Info (EERE)

Kennedy & Van Kennedy & Van Soest, 2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Walker-Lane Transitional Zone Region (Kennedy & Van Soest, 2007) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown Notes The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced permeability and that mantle fluids can penetrate the ductile lithosphere, even in regions where there is no substantial magmatism. Superimposed on the regional trend are local, high 3He/4He anomalies indicating hidden magmatic activity and/or deep

66

Underground helium travels to the Earth's surface via aquifers...  

NLE Websites -- All DOE Office Websites (Extended Search)

carried to the surface with the flow of water. The only place where helium is made on Earth is underground, where deep veins of uranium and thorium give off atoms of helium as...

67

Fluid helium at conditions of giant planetary interiors  

Science Journals Connector (OSTI)

...the nonmetal-to-metal transition in fluid helium . Phys Rev Lett 98 : 190602 . 41 Ternovoi VY Filimonov AS Pyalling AA Mintsev VB Fortov VE ( 2002 ) Thermophysical properties of helium under multiple shock compression in Shock Compression of Condensed...

Lars Stixrude; Raymond Jeanloz

2008-01-01T23:59:59.000Z

68

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

69

Impact of nuclear irradiation on helium bubble nucleation at interfaces in liquid metals coupled to permeation through stainless steels  

E-Print Network (OSTI)

The impact of nucleating gas bubbles in the form of a dispersed gas phase on hydrogen isotope permeation at interfaces between liquid metals, like LLE, and structural materials, like stainless steel, has been studied. Liquid metal to structural material interfaces involving surfaces, may lower the nucleation barrier promoting bubble nucleation at active sites. Hence, hydrogen isotope absorption into gas bubbles modelling and control at interfaces may have a capital importance regarding design, operation and safety. He bubbles as a permeation barrier principle is analysed showing a significant impact on hydrogen isotope permeation, which may have a significant effect on liquid metal systems, e.g., tritium extraction systems. Liquid metals like LLE under nuclear irradiation in, e.g., breeding blankets of a nuclear fusion reactor would generate tritium which is to be extracted and recirculated as fuel. At the same time that tritium is bred, helium is also generated and may precipitate in the form of nano bubbles...

Fradera, Jorge

2013-01-01T23:59:59.000Z

70

Potential applications of high temperature helium  

SciTech Connect

This paper discusses the DOE MHTGR-SC program`s recent activity to improve the economics of the MHTGR without sacrificing safety performance and two potential applications of high temperature helium, the MHTGR gas turbine plant and a process heat application for methanol production from coal.

Schleicher, R.W. Jr.; Kennedy, A.J.

1992-09-01T23:59:59.000Z

71

Potential applications of high temperature helium  

SciTech Connect

This paper discusses the DOE MHTGR-SC program's recent activity to improve the economics of the MHTGR without sacrificing safety performance and two potential applications of high temperature helium, the MHTGR gas turbine plant and a process heat application for methanol production from coal.

Schleicher, R.W. Jr.; Kennedy, A.J.

1992-09-01T23:59:59.000Z

72

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)...

73

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

74

Isotopic Analysis-Fluid At Geysers Geothermal Area (1982) | Open Energy  

Open Energy Info (EERE)

82) 82) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis-Fluid At Geysers Geothermal Area (1982) Exploration Activity Details Location Geysers Geothermal Area Exploration Technique Isotopic Analysis-Fluid Activity Date 1982 Usefulness not indicated DOE-funding Unknown Notes Helium isotope ratios have been measured in geothermal fluids. These ratios have been interpreted in terms of the processes which supply He in distinct isotopic ratios (i.e. magmatic He, ~10 Ra; atmospheric He, Ra; and crustal He, ~0.1 Ra) and in terms of the processes which can alter the isotopic ratio (hydrologic mixing, U-Th series alpha production and weathering release of crustal He, magma aging and tritiugenic addition of 3He). Raft

75

Proposed method for laser spectroscopy of pionic helium atoms to determine the charged-pion mass  

E-Print Network (OSTI)

Metastable pionic helium ($\\pi{\\rm He}^+$) is a three-body atom composed of a helium nucleus, an electron occupying the $1s$ ground state, and a negatively charged pion $\\pi^-$ in a Rydberg state with principal- and orbital angular momentum quantum numbers of $n\\sim \\ell+1\\sim 16$. We calculate the spin-independent energies of the $\\pi{\\rm ^3He}^+$ and $\\pi{\\rm ^4He}^+$ isotopes in the region $n=15$--19. These include relativistic and quantum electrodynamics corrections of orders $R_{\\infty}\\alpha^2$ and $R_{\\infty}\\alpha^3$ in atomic units, where $R_{\\infty}$ and $\\alpha$ denote the Rydberg and fine structure constants. The fine-structure splitting due to the coupling between the electron spin and the orbital angular momentum of the $\\pi^-$, and the radiative and Auger decay rates of the states are also calculated. Some states $(n,\\ell)=(16,15)$ and $(17,16)$ retain nanosecond-scale lifetimes against $\\pi^-$ absorption into the helium nucleus. We propose to use laser pulses to induce $\\pi^-$ transitions from these metastable states, to states with large ($\\sim 10^{11}$ s$^{-1}$) Auger rates. The $\\pi{\\rm He}^{2+}$ ion that remains after Auger emission of the $1s$ electron undergoes Stark mixing with the $s$, $p$, and $d$ states during collisions with the helium atoms in the experimental target. This leads to immediate nuclear absorption of the $\\pi^-$. The resonance condition between the laser beam and the atom is thus revealed as a sharp spike in the rates of neutrons, protons, deuterons, and tritons that emerge....(continued)

Masaki Hori; Anna Sótér; Vladimir I. Korobov

2014-04-30T23:59:59.000Z

76

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

77

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

78

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

79

ARM - Measurement - Isotope ratio  

NLE Websites -- All DOE Office Websites (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

80

Combined cold compressor/ejector helium refrigerator  

DOE Patents (OSTI)

A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

Brown, Donald P. (Southold, NY)

1985-01-01T23:59:59.000Z

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

Combined cold compressor/ejector helium refrigerator  

DOE Patents (OSTI)

A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

Brown, D.P.

1984-06-05T23:59:59.000Z

82

Isotope engineering of silicon and diamond for quantum computing and sensing applications  

E-Print Network (OSTI)

Some of the stable isotopes of silicon and carbon have zero nuclear spin, whereas many of the other elements that constitute semiconductors consist entirely of stable isotopes that have nuclear spins. Silicon and diamond crystals composed of nuclear-spin-free stable isotopes (Si-28, Si-30, or C-12) are considered to be ideal host matrixes to place spin quantum bits (qubits) for quntum computing and sensing applications because their coherent properties are not disrupted thanks to the absence of host nuclear spins. The present article describes the state-of-the-art and future perspective of silicon and diamond isotope engineering for development of quantum information processing devices.

Kohei M. Itoh; Hideyuki Watanabe

2014-10-15T23:59:59.000Z

83

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...

84

In situ controlled modification of the helium density in single helium-filled nanobubbles  

SciTech Connect

We demonstrate that the helium density and corresponding pressure can be modified in single nano-scale bubbles embedded in semiconductors by using the electron beam of a scanning transmission electron microscope as a multifunctional probe: the measurement probe for imaging and chemical analysis and the irradiation source to modify concomitantly the pressure in a controllable way by fine tuning of the electron beam parameters. The control of the detrapping rate is achieved by varying the experimental conditions. The underlying physical mechanisms are discussed; our experimental observations suggest that the helium detrapping from bubbles could be interpreted in terms of direct ballistic collisions, leading to the ejection of the helium atoms from the bubble.

David, M.-L., E-mail: marie-laure.david@univ-poitiers.fr; Pailloux, F. [Institut Pprime, UPR 3346 CNRS-Université de Poitiers, SP2MI, 86962 Futuroscope-Chasseneuil cedex (France); Canadian Centre for Electron Microscopy, Mc Master University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Alix, K.; Mauchamp, V.; Pizzagalli, L. [Institut Pprime, UPR 3346 CNRS-Université de Poitiers, SP2MI, 86962 Futuroscope-Chasseneuil cedex (France); Couillard, M.; Botton, G. A. [Canadian Centre for Electron Microscopy, Mc Master University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Department of Materials Science and Engineering, Mc Master University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada)

2014-03-28T23:59:59.000Z

85

Neutron-induced helium implantation in GCFR cladding  

SciTech Connect

The neutron-induced implantation of helium atoms on the exterior surfaces of the cladding of a prototypic gas-cooled fast reactor (GCFR) has been investigated analytically. A flux of recoil helium particles as high as 4.2 x 10/sup 10/ He/cm/sup 2/.s at the cladding surface has been calculated at the peak power location in the core of a 300-MWe GCFR. The calculated profile of the helium implantation rates indicates that although some helium is implanted as deep as 20 ..mu..m, more than 99% of helium particles are implanted in the first 2-..mu..m-deep layer below the cladding surface. Therefore, the implanted helium particles should mainly affect surface properties of the GCFR cladding.

Yamada, H.; Poeppel, R. B.; Sevy, R. H.

1980-10-01T23:59:59.000Z

86

Nuclear sizes and the isotope shift  

Science Journals Connector (OSTI)

Darwin-Foldy nuclear-size corrections in electronic atoms and nuclear radii are discussed from the nuclear-physics perspective. The interpretation of precise isotope-shift measurements is formalism dependent, and care must be exercised in interpreting these results and those obtained from relativistic electron scattering from nuclei. We strongly advocate that the entire nuclear-charge operator be used in calculating nuclear-size corrections in atoms rather than relegating portions of it to the nonradiative recoil corrections. A preliminary examination of the intrinsic deuteron radius obtained from isotope-shift measurements suggests the presence of small meson-exchange currents (exotic binding contributions of relativistic order) in the nuclear charge operator, which contribute approximately 12%.

J. L. Friar; J. Martorell; D. W. L. Sprung

1997-12-01T23:59:59.000Z

87

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

88

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

SciTech Connect

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

Jewett, J.R., Fluor Daniel Hanford

1997-02-24T23:59:59.000Z

89

Helium 4 Dimer in Two Coaxial Adjacent Nanotubes  

Science Journals Connector (OSTI)

The ground state properties of the helium 4 dimer, within the geometry defined by two adjacent nanotubes with different radii and hard core walls,...

J. Brana; S. Kili?; L. Vranješ

2002-01-01T23:59:59.000Z

90

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

91

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

92

Stable isotope enrichment  

SciTech Connect

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

93

EMSL - isotopic ratio  

NLE Websites -- All DOE Office Websites (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...

94

Alternatives for Helium-3 in Multiplicity Counters  

SciTech Connect

Alternatives to helium-3 are being actively pursued due to the shortage and rising costs of helium-3. For safeguards applications, there are a number of ongoing investigations to find alternatives that provide the same capability in a cost-effective manner. One of the greatest challenges is to find a comparable alternative for multiplicity counters, since they require high efficiency and short collection or die-away times. Work has been progressing on investigating three commercially available alternatives for high efficiency multiplicity counters: boron trifluoride (BF3) filled proportional tubes, boron-lined proportional tubes, and lithium fluoride with zinc sulfide coated light guides. The baseline multiplicity counter used for the investigation is the Epithermal Neutron Multiplicity Counter with 121 helium-3 filled tubes at 10 atmosphere pressure, which is a significant capability to match. The primary tool for the investigation has been modeling and simulation using the Monte Carlo N-Particle eXtended (MCNPX) radiation transport program, with experiments to validate the models. To directly calculate the coincidence rates in boron-lined (and possibly other) detectors, the MCNPX code has been enhanced to allow the existing coincidence tally to be used with energy deposition rather than neutron capture reactions. This allows boron-lined detectors to be modeled more accurately. Variations of tube number and diameter along with variations in the amount of inter-tube moderator have been conducted for the BF3 and boron-lined cases. Tube pressure was investigated for BF3, up to two atmospheres, as well as optimal boron thickness in the boron-lined tubes. The lithium fluoride was modeled as sheets of material with light guides in between, and the number and thickness of the sheets investigated. The amount of light guide, which in this case doubles as a moderator, was also optimized. The results of these modeling and simulation optimization investigations are described and results presented.

Ely, James H.; Siciliano, Edward R.; Lintereur, Azaree T.; Swinhoe, Martyn T.

2013-04-01T23:59:59.000Z

95

Kosterlitz-Thouless Transition in Helium Films  

E-Print Network (OSTI)

and the Materials Science Center, Cornell University, Ithaca, Xetv York 14853 (Received 4 November 1988) The superAuid response of helium Alms with transition temperatures ranging from 70 mK to 0.5 K has been studied using a torsional oscillator technique. A... KOSTERLITZ- THOULESS TRANSITION IN. . . 8935 =n ~Koln(R/ro)+E, (T), (1.2) where R is the size of the system and Ko =p, o( T)(A'/m) . In the above expression the core radius ro serves to cut off the divergence of the flow fields at small distances...

Agnolet, Glenn; MCQUEENEY, DF; REPPY, JD.

1989-01-01T23:59:59.000Z

96

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

97

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

98

RECENT ADVANCES IN HEAT TRANSFER TO HELIUM 1  

E-Print Network (OSTI)

509 RECENT ADVANCES IN HEAT TRANSFER TO HELIUM 1 C. JOHANNES Service de Recherches Appliquées, L boiling, forced convection heat transfer. Relations between critical nucleate flux and some parameters confronted with the problem of calculating the heat transfer from the helium to the superconducting material

Paris-Sud XI, Université de

99

DIRECT EVALUATION OF THE HELIUM ABUNDANCES IN OMEGA CENTAURI  

SciTech Connect

A direct measure of the helium abundances from the near-infrared transition of He I at 1.08 {mu}m is obtained for two nearly identical red giant stars in the globular cluster Omega Centauri. One star exhibits the He I line; the line is weak or absent in the other star. Detailed non-local thermal equilibrium semi-empirical models including expansion in spherical geometry are developed to match the chromospheric H{alpha}, H{beta}, and Ca II K lines, in order to predict the helium profile and derive a helium abundance. The red giant spectra suggest a helium abundance of Y {<=} 0.22 (LEID 54064) and Y = 0.39-0.44 (LEID 54084) corresponding to a difference in the abundance {Delta}Y {>=} 0.17. Helium is enhanced in the giant star (LEID 54084) that also contains enhanced aluminum and magnesium. This direct evaluation of the helium abundances gives observational support to the theoretical conjecture that multiple populations harbor enhanced helium in addition to light elements that are products of high-temperature hydrogen burning. We demonstrate that the 1.08 {mu}m He I line can yield a helium abundance in cool stars when constraints on the semi-empirical chromospheric model are provided by other spectroscopic features.

Dupree, A. K.; Avrett, E. H., E-mail: dupree@cfa.harvard.edu, E-mail: eavrett@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2013-08-20T23:59:59.000Z

100

A VACANCY MODEL IN SOLID HELIUM IV B. CASTAING  

E-Print Network (OSTI)

536 A VACANCY MODEL IN SOLID HELIUM IV B. CASTAING Groupe de Physique des Solides de l here a new approach to the problem of vacancies in solid Helium 4, describing them as small liquid droplets. In this model the vacancy effective mass is very small : 0.1 mHe, where mHe is the atomic mass

Boyer, Edmond

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101

Steam reformers heated by helium from high temperature reactors  

Science Journals Connector (OSTI)

The manifold possibilities of the application of helium-heated steam reformers combined with high temperature nuclear reactors are elucidated in this article. It is shown that the thermodynamic interpretation of the processes does not cause difficulties because of the good heat transfer in helium at high pressure and that helium peak temperatures of 950°C are sufficient for carrying out the process. The mechanical design of the reformer tube does not lead to problems because the helium and process pressures are so chosen as to be approximately equal. The problems of hydrogen and tritium permeation as well as the contamination of the reformer tube with solid fission products seem to be solvable using the knowledge available at present. Furthermore, the various possibilities for the design arrangements of helium-heated reformer tube furnaces are shown. The status of development attained to date is outlined and in conclusion there is a survey regarding the next steps to be taken in steam reformer technology.

K. Kugeler; M. Kugeler; H.F. Niessen; K.H. Hammelmann

1975-01-01T23:59:59.000Z

102

Double photoionization of helium with synchrotron x-rays: Proceedings  

SciTech Connect

This report contains papers on the following topics: Overview and comparison of photoionization with charged particle impact; The ratio of double to single ionization of helium: the relationship of photon and bare charged particle impact ionization; Double photoionization of helium at high energies; Compton scattering of photons from electrons bound in light elements; Electron ionization and the Compton effect in double ionization of helium; Elimination of two atomic electrons by a single energy photon; Double photoionization of helium at intermediate energies; Double Photoionization: Gauge Dependence, Coulomb Explosion; Single and Double Ionization by high energy photon impact; The effect of Compton Scattering on the double to single ionization ratio in helium; and Double ionization of He by photoionization and Compton scattering. These papers have been cataloged separately for the database.

Not Available

1994-01-01T23:59:59.000Z

103

Industry Perspective  

NLE Websites -- All DOE Office Websites (Extended Search)

idatech.com idatech.com info@idatech.com 63065 NE 18 th Street Bend, OR 97701 541.383.3390 Industry Perspective Biogas and Fuel Cell Workshop National Renewable Energy Laboratory June 11 - 13, 2012 Mike Hicks Chairman of the Board of Directors, FCHEA Treasurer of the Board of Directors, FCS&E Engineering Manager, Technology Development & Integration, IdaTech Outline 1. Critical Factors * Fuel Purity * Fuel Cost 2. Natural Gas - The Wild Card & Competition 3. IdaTech's Experience Implementing Biofuel Critical Factor - Fuel Purity All fuel cell system OEMs have fuel purity specifications * Independent of * Raw materials or feed stocks * Manufacturing process * Depends on * Fuel processor technology * Fuel cell technology - low temp PEM versus SOFC

104

Manufacturing Perspective  

NLE Websites -- All DOE Office Websites (Extended Search)

EOT_RT_Sub_Template.ppt | 1/6/2009 | 1 EOT_RT_Sub_Template.ppt | 1/6/2009 | 1 BOEING is a trademark of Boeing Management Company. Copyright © 2009 Boeing. All rights reserved. Compressed Hydrogen Storage Workshop Manufacturing Perspective Karl M. Nelson (karl.m.nelson@boeing.com) Boeing Research & Technology Engineering, Operations & Technology | Boeing Research & Technology Materials & Fabrication Technology EOT_RT_Sub_Template.ppt | 1/12/2009 | Structural Tech 2 Copyright © 2009 Boeing. All rights reserved. DOE Hydrogen Program Development of Advanced Manufacturing Technologies for Low Cost Hydrogen Storage Vessels Mark Leavitt, Alex Ly Quantum Fuel Systems Technologies Worldwide Inc. Karl Nelson, Brice Johnson The Boeing Company Ken Johnson, Kyle Alvine, Stan Pitman, Michael Dahl, Daryl Brown

105

F Band in Isotopically Enriched LiF  

Science Journals Connector (OSTI)

The effect of isotopic composition on the optical obsorption spectrum of the F center in LiF has been investigated. The results of measurements on single crystals of x-ray irradiated Li6F (almost 96% lithium-6) and Li7F (almost 100% lithium-7) indicate that the average F-band width at half-maximum in the former is larger by about 3% at liquid-helium temperature, and by about 1% at room temperature. Theory shows that the half-widths in the two isotopic forms vary inversely as the fourth root of the mass of the alkali ions at low temperature, and as the temperature is increased the predicted half-width difference monotonically decreases to zero. The predicted half-width difference at low temperatures is about 4%, and at room temperature about 1%, both in reasonable agreement with experiment. At both room and liquid-helium temperatures the position of the F-band maximum in Li7F is slightly displaced to higher energy than in Li6F. The peak-position shift is in approximate agreement with the contributions arising from the difference in alkali mass and lattice constant of the two crystals as estimated at low temperature.

Herbert Rabin and Michael Reich

1964-07-06T23:59:59.000Z

106

Scattering of Fast Neutrons by Helium  

Science Journals Connector (OSTI)

Measurements have been made of the angular distribution of helium recoils for incident neutrons of energies from 0.6 to 1.6 Mev. The distribution curves also permit estimates of the total cross section in this energy range. The results confirm the existence of a cross-section peak of about 6.8×10-24 cm2 around 1 Mev and indicate, under the assumption of s- and p-wave scattering only, that the peak is double. But preliminary attempts to fit the data to Bloch's detailed theory of s- and p-scattering with a split p-level have not been successful, and the sign of the postulated splitting is not established.

T. A. Hall and P. G. Koontz

1947-08-01T23:59:59.000Z

107

Continuous Photoelectric Absorption Cross Section of Helium  

Science Journals Connector (OSTI)

The continuous photoelectric absorption cross section of helium has been measured in the spectral region extending from 180 to 600 A with greater accuracy and the observations are found to agree with the calculations of Huang and Stewart and Wilkinson. A grazing incidence spectrometer with a photomultiplier was used for a single measurement at 180 A while the remaining measurements were carried out in a normal incidence spectrometer utilizing photographic techniques. Whereas in previous experiments the absorbing gas sample was allowed to fill the entire spectrometer chamber, in the current measurements the gas was confined to a small cell provided with sufficiently transparent windows. The use of an absorption cell reduces contamination and facilitates the measurement of gas pressures. The results indicate that the cross section varies from a value of 0.98±0.04 Mb at 180 A to a value of 7.7±0.3 Mb at the absorption edge located at 504 A.

D. J. Baker; Jr.; D. E. Bedo; D. H. Tomboulian

1961-12-01T23:59:59.000Z

108

Helium in the outer solar atmosphere  

Science Journals Connector (OSTI)

We construct models of the outer solar atmosphere comprising the region from the mid chromosphere and into the solar wind in order to study the force and energy balance in models with a significant helium abundance. The corona is created by dissipation of an energy flux from the Sun. The energy flux is lost as radiation from the top of the chromosphere and as gravitational and kinetic solar wind energy flux. We find that in models with significant ion heating of the extended corona most of the energy flux is lost in the solar wind. The ion temperatures are higher than the electron temperature in these models and the ?-particle temperature is much higher than the proton temperature. Roughly speaking we find that the relative ?-particle and proton fluxes are set by the degree of chromospheric mixing while the speeds are set by the details of the coronal heating process.

V. H. Hansteen; E. Leer; T. E. Holzer

1997-01-01T23:59:59.000Z

109

Helium solubility in SON68 nuclear waste glass  

SciTech Connect

Helium behavior in a sodium borosilicate glass (SON68) dedicated to the immobilization of high-level nuclear waste is examined. Two experimental approaches on nonradioactive glass specimens are implemented: pressurized helium infusion experiments and {sup 3}He ion implantation experiments. The temperature variation of helium solubility in SON68 glass was determined and analyzed with the harmonic oscillator model to determine values of the energy of interaction E(0) at the host sites (about -4000 J/mol), the vibration frequency (about 1.7 x 10{sup 11} s{sup -1}), and the density of solubility sites (2.2 x 10{sup 21} sites cm{sup -3}). The implantation experiments show that a non diffusive transport phenomenon (i.e., athermal diffusion) is involved in the material when the helium concentration exceeds 2.3 x 10{sup 21} He cm{sup -3}, and thus probably as soon as it exceeds the density of solubility sites accessible to helium in the glass. We propose that this transport mechanism could be associated with the relaxation of the stress gradient induced by the implanted helium profile, which is favored by the glass damage. Microstructural characterization by TEM and ESEM of glass specimens implanted with high helium concentrations showed a homogeneous microstructure free of bubbles, pores, or cracking at a scale of 10 nm. (authors)

Fares, Toby; Peuget, Sylvain; Bouty, Olivier; Broudic, Veronique; Maugeri, Emilio; Bes, Rene; Jegou, Christophe [CEA, DEN, DTCD SECM LMPA, F-30207 Marcoule, Bagnols Sur Cez, (France); Chamssedine, Fadel; Sauvage, Thierry [CNRS, CEMHTI, F-245071 Orleans, (France); Deschanels, Xavier [LNAR, Marcoule Inst Separat Chem, F-30207 Bagnols Sur Ceze, (France)

2012-12-15T23:59:59.000Z

110

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

111

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

112

Thermophysical Properties of Helium under Multiple Shock Compression  

Science Journals Connector (OSTI)

The results on measurements of thermodynamic properties and electrical conductivity of Helium compressed with shock wave reverberation technique up to pressure and density of 200 GPa and 1.4 g/cc are presented. The increase of the Helium conductivity up to the values of 1000 1/(Ohm?cm) was found at the densities more than 0.7 g/cc and temperature more than 15 kK. Comparison of the experimental results with different theoretical models of thermodynamic and transport properties of shocked Helium was done.

Vladimir Ya. Ternovoi; Alexander S. Filimonov; Alexei A. Pyalling; Viktor B. Mintsev; Vladimir E. Fortov

2002-01-01T23:59:59.000Z

113

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

114

Flow of mantle fluids through the ductile lower crust: Helium isotope trends  

E-Print Network (OSTI)

particularly for geothermal energy development. Mantlex 10 kWh of accessible geothermal energy. This is a sizable

Kennedy, B. Mack; van Soest, Matthijs C.

2008-01-01T23:59:59.000Z

115

Spallation-Fission Competition in Heaviest Elements; Helium Ion Induced Reactions in Plutonium Isotopes  

E-Print Network (OSTI)

James W. Cobble, and Glenn T. Seaborg Radiation LaboratoryJames W. Cobble, and Glenn T. Seaborg Radiation Laboratory

Glass, Richard A.; Carr, Robert J.; Cobble, James W.; Seaborg, Glenn T.

1956-01-01T23:59:59.000Z

116

Flow of mantle fluids through the ductile lower crust: Helium isotope trends  

E-Print Network (OSTI)

particularly for geothermal energy development. Mantlex 10 kWh of accessible geothermal energy. This is a sizableBasic Energy Sciences and Office of Geothermal Technologies

Kennedy, B. Mack; van Soest, Matthijs C.

2008-01-01T23:59:59.000Z

117

HELIUM ISOTOPE COMPOSITION OF FLUID INCLUSIONS HOSTED IN MASSIVE SULFIDES FROM MODERN SUBMARINE HYDROTHERMAL SYSTEMS  

Science Journals Connector (OSTI)

...resistance-heated furnace. Procedural blanks were...inclusions. The crushing efficiency depends on factors such...must be noted that the high-temperature (100...Oomori, T., 1990, Venting of carbon-dioxide-rich...2 orders of magnitude higher than expected for equilibrium...

Volker Lüders; Samuel Niedermann

118

Isotopes of helium, hydrogen, and carbon as groundwater tracers in aquifers along the Colorado River  

E-Print Network (OSTI)

hard rock formations and unconsolidated sediments can act asand Cherry, 1979). Unconsolidated deposits, particularlySemi-Pervious Good Unconsolidated Sand & Gravel Consolidated

Haber, Samuel Ainsworth

2009-01-01T23:59:59.000Z

119

Fermi-liquid droplets in liquid-solid solutions of the helium isotopes  

SciTech Connect

For temperatures below phase separation of 1000-ppm /sup 3/He in solid /sup 4/He we measure a heat capacity ..gamma..T for a pressure between melting of pure /sup 3/He and /sup 4/He. Together with the confined sample geometry this results in liquid /sup 3/He droplets (phiapprox.10/sup 3/A) either dilute or pure depending on the phase diagram topology which is discussed theoretically. In the case of a pure /sup 3/He droplet we find an anomalously high effective mass m*/m=10, which could be explained by paramagnon effects enhanced by the confined geometry.

Hebral, B.; Greenberg, A.S.; Beal-Monod, M.T.; Papoular, M.; Frossati, G.; Godfrin, H.; Thoulouze, D.

1981-01-05T23:59:59.000Z

120

SRS upgrades helium recovery system | National Nuclear Security  

NLE Websites -- All DOE Office Websites (Extended Search)

upgrades helium recovery system | National Nuclear Security upgrades helium recovery system | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Home > NNSA Blog > SRS upgrades helium recovery system SRS upgrades helium recovery system Posted By Office of Public Affairs Savannah River Site (SRS) Tritium Programs recently completed a project to design, build and relocate a new system for separating and capturing

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

Heat Transfer in Liquid Helium below 1 degrees K  

Science Journals Connector (OSTI)

...September 1955 research-article Heat Transfer in Liquid Helium below 1 degrees...is proportional to the specific heat and the diameter of the specimen. Thus the sole mechanism of heat transfer appears to be by phonons which...

1955-01-01T23:59:59.000Z

122

Helium Pumping Wall for a Liquid Lithium Tokamak Richard Majeski...  

NLE Websites -- All DOE Office Websites (Extended Search)

Helium Pumping Wall for a Liquid Lithium Tokamak Richard Majeski This invention is designed to be a subsystem of a device, a tokamak with walls or plasma facing components of...

123

Performance Assessment of a Recuperative Helium Gas Turbine System  

Science Journals Connector (OSTI)

Helium is considered an ideal working fluid for closed cycle gas turbines powered by the heat of nuclear reactors or solar concentrators. Energetic and exergetic based thermodynamic analyses ... applied to an act...

Rami Salah El-Emam; Ibrahim Dincer

2014-01-01T23:59:59.000Z

124

Development of High Expansion Ratio Helium Turbo Expander  

Science Journals Connector (OSTI)

The authors developed a high expansion ratio radial inflow turbine for a helium liquefier of 100 L/h capacity for use with a 70 MW superconductive generator. The following results were obtained from this devel...

N. Ino; A. Machida; K. Ttsugawa; Y. Arai; M. Matsuki…

1991-01-01T23:59:59.000Z

125

Creep properties of Hastelloy-X in impure helium environments  

SciTech Connect

In impure helium environments, Hastelloy-X is susceptible to carburization and oxidation. These effects are investigated separately, and are related to the creep behavior of the alloy. Experiments were carried out at 900/sup 0/C in both helium and air. Carburization resulted in a slight increase of the creep strength up to the onset of the tertial creep. Suppression of the creep crack growth by oxidation was confirmed using notched plate specimens of Inconel alloy 600 and Hastelloy-X. Although the difference of creep strength in air and in helium was very small and considered to be inclusive in the usual scatter, a pessimistic ratio of rupture stress in helium to that in air was estimated to be 0.9.

Nakanishi, T.; Kawakami, H.

1984-08-01T23:59:59.000Z

126

A New Wide Range Equation of State for Helium-4  

E-Print Network (OSTI)

A NEW WIDE RANGE EQUATION OF STATE FOR HELIUM-4 A Dissertation by DIEGO ORLANDO ORTIZ VEGA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR... Copyright 2013Diego Orlando Ortiz Vega ii ABSTRACT A multiparametric and fundamental equation of state is presented for the fluid thermodynamic properties of helium. The equation is valid for temperatures from the ?- line (~2.17 K) to 1500 K...

Ortiz Vega, Diego O

2013-08-01T23:59:59.000Z

127

Process Options for Nominal 2-K Helium Refrigeration System Designs  

SciTech Connect

Nominal 2-K helium refrigeration systems are frequently used for superconducting radio frequency and magnet string technologies used in accelerators. This paper examines the trade-offs and approximate performance of four basic types of processes used for the refrigeration of these technologies; direct vacuum pumping on a helium bath, direct vacuum pumping using full or partial refrigeration recovery, cold compression, and hybrid compression (i.e., a blend of cold and warm sub-atmospheric compression).

Peter Knudsen, Venkatarao Ganni

2012-07-01T23:59:59.000Z

128

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

129

Isotopic Analysis At Cascades Region (Kennedy & Van Soest, 2007) | Open  

Open Energy Info (EERE)

Analysis At Cascades Region (Kennedy & Van Soest, 2007) Analysis At Cascades Region (Kennedy & Van Soest, 2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis-Fluid At Cascades Region (Kennedy & Van Soest, 2007) Exploration Activity Details Location Cascades Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown Notes The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced permeability and that mantle fluids can penetrate the ductile lithosphere, even in regions where there is no substantial magmatism. Superimposed on the regional trend are local, high 3He/4He anomalies indicating hidden magmatic activity and/or deep

130

Isotopic Analysis At Nw Basin & Range Region (Kennedy & Van Soest, 2007) |  

Open Energy Info (EERE)

Nw Basin & Range Region (Kennedy & Van Soest, 2007) Nw Basin & Range Region (Kennedy & Van Soest, 2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Nw Basin & Range Region (Kennedy & Van Soest, 2007) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown Notes The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced permeability and that mantle fluids can penetrate the ductile lithosphere, even in regions where there is no substantial magmatism. Superimposed on the regional trend are local, high 3He/4He anomalies indicating hidden magmatic activity and/or deep

131

Isotopic Analysis At Northern Basin & Range Region (Kennedy & Van Soest,  

Open Energy Info (EERE)

Northern Basin & Range Region (Kennedy & Van Soest, Northern Basin & Range Region (Kennedy & Van Soest, 2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Isotopic Analysis- Fluid At Northern Basin & Range Region (Kennedy & Van Soest, 2007) Exploration Activity Details Location Northern Basin and Range Geothermal Region Exploration Technique Isotopic Analysis- Fluid Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown Notes The correspondence of helium isotope ratios and active transtensional deformation indicates a deformation-enhanced permeability and that mantle fluids can penetrate the ductile lithosphere, even in regions where there is no substantial magmatism. Superimposed on the regional trend are local, high 3He/4He anomalies indicating hidden magmatic activity and/or deep

132

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

133

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

134

GENERATION OF RADIOXENON ISOTOPES  

SciTech Connect

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

135

Detection of significant differences between absorption spectra of neutral helium and low temperature photoionized helium plasmas  

SciTech Connect

In this work, spectral investigations of photoionized He plasmas were performed. The photoionized plasmas were created by irradiation of helium stream, with intense pulses from laser-plasma extreme ultraviolet (EUV) source. The EUV source was based on a double-stream Xe/Ne gas-puff target irradiated with 10 ns/10 J Nd:YAG laser pulses. The most intense emission from the source spanned a relatively narrow spectral region below 20 nm, however, spectrally integrated intensity at longer wavelengths was also significant. The EUV radiation was focused onto a gas stream, injected into a vacuum chamber synchronously with the EUV pulse. The long-wavelength part of the EUV radiation was used for backlighting of the photoionized plasmas to obtain absorption spectra. Both emission and absorption spectra in the EUV range were investigated. Significant differences between absorption spectra acquired for neutral helium and low temperature photoionized plasmas were demonstrated for the first time. Strong increase of intensities and spectral widths of absorption lines, together with a red shift of the K-edge, was shown.

Bartnik, A.; Wachulak, P.; Fiedorowicz, H.; Fok, T.; Jarocki, R.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)] [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)

2013-11-15T23:59:59.000Z

136

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

137

David Lee, Douglas Osheroff, Superfluidity, and Helium 3  

NLE Websites -- All DOE Office Websites (Extended Search)

David Lee, Douglas Osheroff, Superfluidity, and Helium 3 David Lee, Douglas Osheroff, Superfluidity, and Helium 3 Resources with Additional Information David M. Lee and Douglas D. Osheroff received the 1996 Nobel Prize in Physics for 'their discovery of superfluidity in helium-3'. "In 1976, Lee shared with Richardson and Osheroff their earliest recognition for studies of superfluidity, the Simon Memorial Prize of the British Physical Society. The Buckley Prize of the American Physical Society followed for the trio in 1981. ... Douglas D. Osheroff Douglas D. Osheroff Courtesy AIP Emilio Segrè Visual Archives, AIP Meggers Gallery of Nobel Laureates David Lee David M. Lee Photo by Janerik Henriksson, Courtesy AIP Emilio Segrè Visual Archievs, W.F. Meggers Gallery of Nobel Laureate From 1966-67, Lee was a visiting scientist at Brookhaven National Laboratory ... ."1 His research at Cornell University includes " Low Temperature Physics: Normal and superfluid 3He, studies of the orientation of solid helium by optical birefringence, solid 3He and 4He, lambda phase diagram of 3He - 4He mixtures, quasiparticle tunneling in superconductors, magnetic resonance and ultrasound techniques, cooling by adiabatic demagnetization and the Pomeranchuk technique, spin waves in spin polarized hydrogen gas, high concentrations of hydrogen and nitrogen atons via matrix isolation by impurity-helium solids, magnetism, electron spin resonance."2

138

Coexistence of superfluid and solid helium in aerogel  

SciTech Connect

The results of recent neutron scattering studies of solid helium in silica aerogel are discussed. Previously I.V. Kalinin et al., Pis'ma Zh. Eksp. Teor. Fiz. 87 (1), 743 (2008) [JETP Lett. 87 (1), 645 (2008)], we detected the existence of a superfluid phase in solid helium at a temperature below 0.6 K and a pressure of 51 bar, although, according to the phase diagram, helium should be in the solid state under these conditions. This work is a continuation of the above studies whose main goal was to examine the detected phenomenon and to establish basic parameters of the existence of a superfluid phase. We have determined the temperature of the superfluid transition from solid to superfluid helium, T{sub C} = 1.3 K, by analyzing experimental data. The superfluid phase excitation parameters (lifetime, intensity, and energy) have a temperature dependence similar to that of bulk helium. The superfluid phase coexists with the solid phase in the entire measured temperature range from T = 0.05 K to T{sub C} and is a nonequilibrium one and disappears at T{sub C}.

Kalinin, I. V. [Institute for Physics and Power Engineering (Russian Federation); Kats, E. I.; Koza, M. [Institut Laue-Langevin (France); Lauter, V. V. [Oak Ridge National Laboratory (United States); Lauter, H. [Institut Laue-Langevin (France); Puchkov, A. V., E-mail: puchkov@ippe.r [Institute for Physics and Power Engineering (Russian Federation)

2010-08-15T23:59:59.000Z

139

A cryogenic axial-centrifugal compressor for superfluid helium refrigeration  

E-Print Network (OSTI)

CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.

Decker, L; Schustr, P; Vins, M; Brunovsky, I; Lebrun, P; Tavian, L

1997-01-01T23:59:59.000Z

140

Strong nuclear force in cold antihydrogen-helium collisions  

SciTech Connect

We calculate cross sections for elastic scattering and annihilation in antihydrogen-helium collisions at low energies. The calculations are based on the Born-Oppenheimer approximation, and incorporate the effects of the strong interaction through a scattering length approach. We find that the strong nuclear force not only causes significant annihilation, but also cannot be neglected in the elastic channel. In the zero energy limit we obtain the scattering length a=-7.69-3.80i a.u. for ground state antihydrogen-helium collisions. Annihilation is found to dominate over elastic scattering up to a temperature about 3 K. Loosely bound metastable antihydrogen-helium states are also investigated, and it is found that a number of relatively long-lived states with up to three units of angular momentum exist.

Jonsell, S. [Department of Physics, Umeaa University, SE-90187 Umeaa (Sweden); Froelich, P.; Eriksson, S. [Department of Quantum Chemistry, Box 518, Uppsala University, SE-75120 Uppsala (Sweden); Strasburger, K. [Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

2004-12-01T23:59:59.000Z

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

Isotopes Tell Origin and Operation of the Sun  

E-Print Network (OSTI)

The Iron Sun formed on the collapsed core of a supernova and now acts as a magnetic plasma diffuser, as did the precursor star, separating ions by mass. This process covers the solar surface with lightweight elements and with lighter isotopes of each element. Running difference images expose rigid, iron-rich structures below the fluid photosphere made of lightweight elements. The energy source for the Sun and ordinary stars seems to be neutron-emission and neutron-decay, with partial fusion of the decay product, rather than simple fusion of hydrogen into helium or heavier elements. Neutron-emission from the solar core and neutron-decay generate about sixty five percent of solar luminosity and H-fusion generates about thirty-five percent. The upward flow of H ions maintains mass-separation in the Sun. Only about one percent of this neutron decay product survives its upward journey to depart as solar-wind hydrogen.

O. Manuel; Sumeet A. Kamat; Michael Mozina

2005-09-28T23:59:59.000Z

142

Supercritical Helium Cooling of the LHC Beam Screens  

E-Print Network (OSTI)

The cold mass of the LHC superconducting magnets, operating in pressurised superfluid helium at 1.9 K, must be shielded from the dynamic heat loads induced by the circulating particle beams, by means of beam screens maintained at higher temperature. The beam screens are cooled between 5 and 20 K by forced flow of weakly supercritical helium, a solution which avoids two-phase flow in the long, narr ow cooling channels, but still presents a potential risk of thermohydraulic instabilities. This problem has been studied by theoretical modelling and experiments performed on a full-scale dedicated te st loop.

Hatchadourian, E; Tavian, L

1998-01-01T23:59:59.000Z

143

White Dwarfs in NGC 6791: Avoiding the Helium Flash  

E-Print Network (OSTI)

We propose that the anomalously bright white dwarf luminosity function observed in NGC 6791 (Bedin et al 2005) is the consequence of the formation of 0.5 Msun white dwarfs with Helium cores instead of Carbon cores. This may happen if mass loss during the ascent of the Red Giant Branch is strong enough to prevent a star from reaching the Helium flash. Such a model can explain the slower white dwarf cooling (relative to standard models) and fits naturally with scenarios advanced to explain Extreme Horizontal Branch stars, a population of which are also found in this cluster.

Brad Hansen

2005-07-12T23:59:59.000Z

144

Radial characterisation of the helium plasma produced by the axial injection torch (TIA) at atmospheric pressure  

Science Journals Connector (OSTI)

This work presents the radial characterisation of a helium plasma produced by the “Torch à Injection Axiale ... using a collisional-radiative model for helium at atmospheric pressure, the electronic density and e...

R. Álvarez; A. Rodero; M. C. Quintero

2000-03-01T23:59:59.000Z

145

Date: Thursday May 23, 2013 Program: UHV Helium Ion Microscopy HR  

E-Print Network (OSTI)

Date: Thursday May 23, 2013 Program: UHV Helium Ion Microscopy HR Speakers: Gregor Hlawacek Helium selected investigations performed with the UTwente UHV-HIM in the last few years. The actual challenge, why

Twente, Universiteit

146

DESIGN OPTIMIZATION OF HIGH-PERFORMANCE HELIUM-COOLED DIVERTOR PLATE CONCEPT  

E-Print Network (OSTI)

DESIGN OPTIMIZATION OF HIGH-PERFORMANCE HELIUM-COOLED DIVERTOR PLATE CONCEPT X.R. Wanga , S Consulting, Fliederweg 3, 76351 Linkenheim, Germany A helium-cooled plate-type divertor design concept has of the concept in the high heat flux zone. This paper describes the design optimization of the helium

Raffray, A. René

147

SUSTAINABILITY New Perspectives  

E-Print Network (OSTI)

the basic principle of sustainability to all areas of human activity, from energy to all manner of consumerSUSTAINABILITY New Perspectives and Opportunities Globalization TrendLab 2012 #12;Globalization TrendLab 2012 Sustainability New Perspectives and Opportunities #12;Based on a conference organized

Edwards, Paul N.

148

Turbulent Mixing on Helium-Accreting White Dwarfs  

E-Print Network (OSTI)

An attractive scenario for producing Type Ia supernovae (SNe Ia) is a double detonation, where detonation of an accreted helium layer triggers ignition of a C/O core. Whether or not such a mechanism can explain some or most SNe Ia depends on the properties of the helium burning, which in turn is set by the composition of the surface material. Using a combination of semi-analytic and simple numerical models, I explore when turbulent mixing due to hydrodynamic instabilities during the accretion process can mix C/O core material up into the accreted helium. Mixing is strongest at high accretion rates, large white dwarf (WD) masses, and slow spin rates. The mixing would result in subsequent helium burning that better matches the observed properties of SNe Ia. In some cases, there is considerable mixing that can lead to more than 50% C/O in the accreted layer at the time of ignition. These results will hopefully motivate future theoretical studies of such strongly mixed conditions. Mixing also has implications for...

Piro, Anthony L

2015-01-01T23:59:59.000Z

149

Heat Transfer Between Solids and Liquid Helium II  

Science Journals Connector (OSTI)

...February 1961 research-article Heat Transfer Between Solids and Liquid Helium...According to this author, the transfer of heat from the solid surface to the...least, some other mechanism of heat transfer may be involved. The Royal Society...

1961-01-01T23:59:59.000Z

150

Thermonuclear .Ia Supernovae from Helium Shell Detonations: Explosion Models and Observables  

Science Journals Connector (OSTI)

During the early evolution of an AM Canum Venaticorum system, helium is accreted onto the surface of a white dwarf under conditions suitable for unstable thermonuclear ignition. The turbulent motions induced by the convective burning phase in the He envelope become strong enough to influence the propagation of burning fronts and may result in the onset of a detonation. Such an outcome would yield radioactive isotopes and a faint rapidly rising thermonuclear ".Ia" supernova. In this paper, we present hydrodynamic explosion models and observable outcomes of these He shell detonations for a range of initial core and envelope masses. The peak UVOIR bolometric luminosities range by a factor of 10 (from 5 ? 1041 to 5 ? 1042 erg s–1), and the R-band peak varies from M R,peak = –15 to –18. The rise times in all bands are very rapid (40Ca through 56Ni) and unburnt He. Thus, the spectra around peak light lack signs of intermediate-mass elements and are dominated by Ca II and Ti II features, with the caveat that our radiative transfer code does not include the nonthermal effects necessary to produce He features.

Ken J. Shen; Dan Kasen; Nevin N. Weinberg; Lars Bildsten; Evan Scannapieco

2010-01-01T23:59:59.000Z

151

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

152

Instructions for filling liquid Helium for the 800 MHz magnet This is a twoperson job and will require 2 x 100 liter tanks of liquid helium if filling  

E-Print Network (OSTI)

and will require 2 x 100 liter tanks of liquid helium if filling from 207 mm (41%). · Move the ladder to the side and place the helium tank to the right of the leg facing the 500 system and as close to the magnet as possible. · Cut all ties from the helium tanks · Hand tighten the homemade fitting to the vent port

Oliver, Douglas L.

153

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

154

Advanced isotope separation  

SciTech Connect

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

155

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

156

Isotope Development & Production | Nuclear Science | ORNL  

NLE Websites -- All DOE Office Websites (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...

157

Cogeneration - A Utility Perspective  

E-Print Network (OSTI)

are discussed from a utility perspective as how they influence utility participation in future projects. The avoided cost methodology is examined, and these payments for sale of energy to the utility are compared with utility industrial rates. In addition...

Williams, M.

1983-01-01T23:59:59.000Z

158

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.

159

IMPROVEMENTS OF HELIUM LIQUEFACTION/REFRIGERATION PLANTS AND APPLICATIONS  

Science Journals Connector (OSTI)

Design features for a new range of helium liquefiers and refrigerators with capacities ranging from 30 to 280 l/h of liquid helium (LHe) and 100 to 900 Watt respectively. The latest He cold box development shows an increased efficiency due to improved turbine and heat exchanger design. Other benefits of the new design include short cool-down times and a very compact design which offers better flexibility and process control. The modularity of the system was designed in order to cover a wide range of applications like sophisticated shield cooling at different temperature levels or simultaneous operation modes for He liquefaction and refrigeration purposes. The presentation will highlight the individual improvements in the design.

K.-H. Berdais; H. Wilhelm; Th. Ungricht

2008-01-01T23:59:59.000Z

160

Elastic Electron Scattering from Tritium and Helium-3  

DOE R&D Accomplishments (OSTI)

The mirror nuclei of tritium and helium-3 have been studied by the method of elastic electron scattering. Absolute cross sections have been measured for incident electron energies in the range 110 - 690 MeV at scattering angles lying between 40 degrees and 135 degrees in this energy range. The data have been interpreted in a straightforward manner and form factors are given for the distributions of charge and magnetic moment in the two nuclei over a range of four-momentum transfer squared 1.0 - 8.0 F{sup -2}. Model-independent radii of the charge and magnetic moment distributions are given and an attempt is made to deduce form factors describing the spatial distribution of the protons in tritium and helium-3.

Collard, H.; Hofstadter, R.; Hughes, E. B.; Johansson, A.; Yearian, M. R.; Day, R. B.; Wagner, R. T.

1964-10-00T23:59:59.000Z

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

Coefficients of the second viscosity in bulk liquid helium  

Science Journals Connector (OSTI)

The coefficients of the second viscosity in bulk liquid helium are evaluated explicitly as a function of temperature via interactions between the anomalous excitation spectrums. The four coefficients of the second viscosity exhibit a T-1 dependence at low temperatures (well below 0.6 K), which is due to three-phonon processes originating from the anomalous dispersion at very low momenta and temperatures.

Chung-In Um; Chul-Won Jun; Thomas F. George

1992-09-01T23:59:59.000Z

162

Multiple reheat helium Brayton cycles for sodium fast reactors  

SciTech Connect

Sodium fast reactors (SFR) traditionally adopt the steam Rankine cycle for power conversion. The resulting potential for water-sodium reaction remains a continuing concern which at least partly delays the SFR technology commercialization and is a contributor to higher capital cost. Supercritical CO2 provides an alternative, but is also capable of sustaining energetic chemical reactions with sodium. Recent development on advanced inert-gas Brayton cycles could potentially solve this compatibility issue, increase thermal efficiency, and bring down the capital cost close to light water reactors. In this paper, helium Brayton cycles with multiple reheat and intercooling states are presented for SFRs with reactor outlet temperatures in the range of 510°C to 650°C. The resulting thermal efficiencies range from 39% and 47%, which is comparable with supercritical recompression CO2 cycles (SCO2 cycle). A systematic comparison between multiple reheat helium Brayton cycle and the SCO2 cycle is given, considering compatibility issues, plant site cooling temperature effect on plant efficiency, full plant cost optimization, and other important factors. The study indicates that the multiple reheat helium cycle is the preferred choice over SCO2 cycle for sodium fast reactors.

Haihua Zhao; Per F. Peterson

2008-07-01T23:59:59.000Z

163

Mathematical modeling of a Fermilab helium liquefier coldbox  

SciTech Connect

Fermilab Central Helium Liquefier (CHL) facility is operated 24 hours-a-day to supply 4.6{degrees}K for the Fermilab Tevatron superconducting proton-antiproton collider Ring and to recover warm return gases. The centerpieces of the CHL are two independent cold boxes rated at 4000 and 5400 liters/hour with LN{sub 2} precool. These coldboxes are Claude cycle and have identical heat exchangers trains, but different turbo-expanders. The Tevatron cryogenics demand for higher helium supply from CHL was the driving force to investigate an installation of an expansion engine in place of the Joule-Thompson valve. A mathematical model was developed to describe the thermo- and gas-dynamic processes for the equipment included in the helium coldbox. The model is based on a finite element approach, opposite to a global variables approach, thus providing for higher accuracy and conversion stability. Though the coefficients used in thermo- and gas-dynamic equations are unique for a given coldbox, the general approach, the equations, the methods of computations, and most of the subroutines written in FORTRAN can be readily applied to different coldboxes. The simulation results are compared against actual operating data to demonstrate applicability of the model.

Geynisman, M.G.; Walker, R.J.

1995-12-01T23:59:59.000Z

164

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

165

The Helium-Core Mass at the Helium Flash in Low-Mass Red Giant Stars: Observations and Theory  

E-Print Network (OSTI)

The method developed by Raffelt (1990a,b,c) to estimate a possible increase in the standard values of the helium-core mass at the tip of the red giant branch, $\\Mc$, from properties of the color-magnitude diagrams of Galactic globular clusters is employed. In the present study, we revise and update Raffelt's database, including also constraints from RR Lyrae pulsation, and find that a small increase, by $\\Delta\\Mc \\approx 0.01\\pm 0.015 \\Msun$, cannot be ruled out with the present data and evolutionary models. Our new upper limits on $\\Delta\\Mc$ are less restrictive than those previously obtained by Raffelt, as are the corresponding constraints on novel astroparticle phenomena which may affect the evolution of low-mass red giants. Within the estimated uncertainties, however, the standard values of $\\Mc$ may also be acceptable. Raffelt's method does not rule out a low envelope helium abundance in globular cluster giants, though again the standard values are compatible with the available constraints. The influence of a non-solar ratio for the $\\alpha$-capture elements upon these results is also investigated. In addition, we review several aspects of the input physics employed in red giant stellar evolutionary calculations, with the purpose of evaluating possible sources of uncertainty in the value of the helium-core mass at the helium flash that is obtained from evolutionary computations, such as: heat conduction by electrons in the degenerate core; Coulomb effects upon the Equation of State; triple-$\\alpha$ reaction rates and screening factors; neutrino emission rates, both standard and enhanced by a possible non-zero magnetic moment; stellar rotation; microscopic element diffusion; and energy losses by axions and Weakly Interacting Massive Particles.

M. Catelan; J. A. de Freitas Pacheco; J. E. Horvath

1995-09-12T23:59:59.000Z

166

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.

167

Production of carbon monoxide-free hydrogen and helium from a high-purity source  

DOE Patents (OSTI)

The invention provides vacuum swing adsorption processes that produce an essentially carbon monoxide-free hydrogen or helium gas stream from, respectively, a high-purity (e.g., pipeline grade) hydrogen or helium gas stream using one or two adsorber beds. By using physical adsorbents with high heats of nitrogen adsorption, intermediate heats of carbon monoxide adsorption, and low heats of hydrogen and helium adsorption, and by using vacuum purging and high feed stream pressures (e.g., pressures of as high as around 1,000 bar), pipeline grade hydrogen or helium can purified to produce essentially carbon monoxide -free hydrogen and helium, or carbon monoxide, nitrogen, and methane-free hydrogen and helium.

Golden, Timothy Christopher (Allentown, PA); Farris, Thomas Stephen (Bethlehem, PA)

2008-11-18T23:59:59.000Z

168

Effects of sequential tungsten and helium ion implantation on nano-indentation hardness of tungsten  

SciTech Connect

To simulate neutron and helium damage in a fusion reactor first wall sequential self-ion implantation up to 13 dpa followed by helium-ion implantation up to 3000 appm was performed to produce damaged layers of {approx}2 {mu}m depth in pure tungsten. The hardness of these layers was measured using nanoindentation and was studied using transmission electron microscopy. Substantial hardness increases were seen in helium implanted regions, with smaller hardness increases in regions which had already been self-ion implanted, thus, containing pre-existing dislocation loops. This suggests that, for the same helium content, helium trapped in distributed vacancies gives stronger hardening than helium trapped in vacancies condensed into dislocation loops.

Armstrong, D. E. J.; Edmondson, P. D.; Roberts, S. G. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)] [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

2013-06-24T23:59:59.000Z

169

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

170

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

171

Gas-chromatographische Bestimmung von Wasserstoff bei Verwendung von Helium als Trägergas  

Science Journals Connector (OSTI)

Die bei dem Trägergas Helium zuweilen auftretenden M-förmigen Wasserstoffpeaks lassen sich durch Vergrößern oder Verkleinern des Probenvolumens in eine auswertbare Form bringen.

Holm Pauschmann

1964-01-01T23:59:59.000Z

172

Interim Report on the Optimization and Feasibility Studies for the Neutron Detection without Helium-3 Project  

SciTech Connect

This report provides the status and results of the first year's effort in modeling and simulation to investigate alternatives to helium-3 for neutron detection in safeguards applications.

Ely, James H.

2012-03-19T23:59:59.000Z

173

Atmospheric Pressure Helium Plasma Jet with Different Types of Discharge Setup  

Science Journals Connector (OSTI)

New techniques are demonstrated to generate cold plasma inside the glass capillary and hollow optical fiber. The plasma jet is generated using helium gas and experiments are carried...

Hosseinzadeh Kassani, Sahar; Lee, Changyoung; Yoon, Changsik; Choi, Honggu; Oh, Kyunghwan

174

Atmospheric-Pressure Helium Inductively Coupled Plasmas for Elemental Mass Spectrometry  

Science Journals Connector (OSTI)

Analytical and fundamental characteristics of helium inductively coupled plasma mass spectrometry (He ICPMS) were explored for atmospheric-pressure plasmas generated in a 13-mm He...

Zhang, Hao; Nam, Sang-Ho; Cai, Mingxiang; Montaser, Akbar

1996-01-01T23:59:59.000Z

175

Microsoft Word - 911138_0_SSC-6 Helium Circulator Test Plan_rel...  

NLE Websites -- All DOE Office Websites (Extended Search)

SERVICES FOR THE NEXT GENERATION NUCLEAR PLANT (NGNP) WITH HYDROGEN PRODUCTION Test Plan for Helium Circulators (PHTS, SCS, SHTS) Prepared by General Atomics For the...

176

Onboard Hydrogen/Helium Sensors in Support of the Global Technical...  

NLE Websites -- All DOE Office Websites (Extended Search)

Onboard HydrogenHelium Sensors in Support of the Global Technical Regulation: An Assessment of Performance in Fuel Cell Electric Vehicle Crash Tests Matthew B. Post, Robert...

177

Ultra high vacuum pumping system and high sensitivity helium leak detector  

DOE Patents (OSTI)

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

Myneni, Ganapati Rao (Yorktown, VA)

1997-01-01T23:59:59.000Z

178

Ultra high vacuum pumping system and high sensitivity helium leak detector  

DOE Patents (OSTI)

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10{sup {minus}13} atm cc/s. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces back streaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium. 2 figs.

Myneni, G.R.

1997-12-30T23:59:59.000Z

179

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

NLE Websites -- All DOE Office Websites (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...

180

Copper isotope fractionation in acid mine drainage. | EMSL  

NLE Websites -- All DOE Office Websites (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...

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

Isotope production facility produces cancer-fighting actinium  

NLE Websites -- All DOE Office Websites (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...

182

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

183

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

184

Helium Refrigerator Design for Pulsed Heat Load in Tokamaks  

SciTech Connect

Nuclear fusion reactors of the Tokamak type will be operated in a pulsed mode requiring the helium refrigerator to remove periodically large heat loads in time steps of approximately one hour. What are the necessary steps for a refrigerator to cope with such load variations?A series of numerical simulations has been performed indicating the possibility of an active refrigerator control with low exergetic losses. A basic comparison is made between the largest existing refrigerator sizes and the size required to service for example the ITER requirements.

Kuendig, A.; Schoenfeld, H. [Linde Kryotechnik AG, Dattlikonerstrasse 5, CH-8422 Pfungen (Switzerland)

2006-04-27T23:59:59.000Z

185

Cathode fall measurement in a dielectric barrier discharge in helium  

SciTech Connect

A method based on the “zero-length voltage” extrapolation is proposed to measure cathode fall in a dielectric barrier discharge. Starting, stable, and discharge-maintaining voltages were measured to obtain the extrapolation zero-length voltage. Under our experimental conditions, the “zero-length voltage” gave a cathode fall of about 185 V. Based on the known thickness of the cathode fall region, the spatial distribution of the electric field strength in dielectric barrier discharge in atmospheric helium is determined. The strong cathode fall with a maximum field value of approximately 9.25 kV/cm was typical for the glow mode of the discharge.

Hao, Yanpeng; Zheng, Bin; Liu, Yaoge [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)] [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)

2013-11-15T23:59:59.000Z

186

Radiative Lifetimes of Some Electronic States of Helium  

Science Journals Connector (OSTI)

In this paper we describe our measurements of the radiative lifetimes of the 3 3 P 3 3 D 4 1 D and 4 3 D electronic states of helium using a low-energy positive ion accelerator. The lifetimes in nanoseconds are 3 3 P?(111±5) 3 3 D?(14±3) 4 1 D?(34±4) and 4 3 D?(32±1) . In addition we discuss the desirability and feasibility of introducing undergraduates to this type of research.

Stanley A. Chin-Bing; Charles E. Head; Albert E. Green Jr.

1970-01-01T23:59:59.000Z

187

A pencil beam algorithm for helium ion beam therapy  

SciTech Connect

Purpose: To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. Methods: The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10{sup 7} ions per beam. For comparison a special evaluation software was developed calculating the gamma indices for dose distributions. Results: In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy falloff of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a {gamma}-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the {gamma}-index criterion was exceeded in some areas giving a maximum {gamma}-index of 1.75 and 4.9% of the voxels showed {gamma}-index values larger than one. The calculation precision of the presented algorithm was considered to be sufficient for clinical practice. Although only data for helium beams was presented, the performance of the pencil beam algorithm for proton beams was comparable. Conclusions: The pencil beam algorithm developed for helium ions presents a suitable tool for dose calculations. Its calculation speed was evaluated to be similar to other published pencil beam algorithms. The flexible design allows easy customization of measured depth-dose distributions and use of varying beam profiles, thus making it a promising candidate for integration into future treatment planning systems. Current work in progress deals with RBE effects of helium ions to complete the model.

Fuchs, Hermann; Stroebele, Julia; Schreiner, Thomas; Hirtl, Albert; Georg, Dietmar [Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria); PEG MedAustron, 2700 Wiener Neustadt (Austria); Department of Nuclear Medicine, Medical University of Vienna, 1090 Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna (Austria); Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria)

2012-11-15T23:59:59.000Z

188

Quartz Tuning Fork: Thermometer, Pressure- and Viscometer for Helium Liquids  

E-Print Network (OSTI)

Commercial quartz oscillators of the tuning-fork type with a resonant frequency of ~32 kHz have been investigated in helium liquids. The oscillators are found to have at best Q values in the range 10^5-10^6, when measured in vacuum below 1.5 K. However, the variability is large and for very low temperature operation the sensor has to be preselected. We explore their properties in the regime of linear viscous hydrodynamic response in normal and superfluid 3He and 4He, by comparing measurements to the hydrodynamic model of the sensor.

R. Blaauwgeers; M. Blazkova; M. Clovecko; V. B. Eltsov; R. de Graaf; J. Hosio; M. Krusius; D. Schmoranzer; W. Schoepe; L. Skrbek; P. Skyba; R. E. Solntsev; D. E. Zmeev

2006-08-17T23:59:59.000Z

189

The effect of helium nano-bubbles on the structures stability and electronic properties of palladium tritides: a density functional theory study  

Science Journals Connector (OSTI)

...effect of helium nano-bubbles on the structures stability and electronic properties...found to contain helium gas bubbles. The stability of metal tritides decreases...The effects of helium bubbles on metal tritides are clearly...

2014-01-01T23:59:59.000Z

190

Systems Engineering Perspective  

E-Print Network (OSTI)

Systems Engineering Management An Israeli Perspective C. Gallagher 12 November 2004 #12;The SA'AR 5 1994 Positive Cash Flow Some Extended Warranties On-site Involved Israeli Engineers #12;Characteristics Manning Sea Keeping Stability ---Helicopter Safe ---1200 Tonnes, L/B 6.7 Quality Marine Equipment ---Some

191

Climatological Perspectives on  

E-Print Network (OSTI)

Climatological Perspectives on Flooding in Colorado Nolan Doesken, State ClimatologistNolan Doesken, State Climatologist Colorado Climate CenterColorado Climate Center Presented atPresented at Flood Task Force 2007 KickFlood Task Force 2007 Kick--Off Meeting,Off Meeting, Thursday, March 29, 2007,Thursday

192

Further experiments with liquid helium. C. On the change of electric resistance of pure metals at very low temperatures etc. IV. The resistance of pure mercury at helium temperatures  

Science Journals Connector (OSTI)

Since the appearance of the last Communication dealing with liquid helium temperatures (December 1910) liquid helium has been succesfully transferred from the apparatus in which it was liquefied to another ves...

H. Kamerlingh Onnes

1991-01-01T23:59:59.000Z

193

The helium-rich cataclysmic variable SBSS 1108+574  

E-Print Network (OSTI)

We present time-resolved spectroscopy and photometry of the dwarf nova SBSS 1108+574, obtained during the 2012 outburst. Its quiescent spectrum is unusually rich in helium, showing broad, double-peaked emission lines from the accretion disc. We measure a line flux ratio HeI 5875/Halpha = 0.81 +/- 0.04, a much higher ratio than typically observed in cataclysmic variables (CVs). The outburst spectrum shows hydrogen and helium in absorption, with weak emission of Halpha and HeI 6678, as well as strong HeII emission. From our photometry, we find the superhump period to be 56.34 +/- 0.18 minutes, in agreement with the previously published result. The spectroscopic period, derived from the radial velocities of the emission lines, is found to be 55.3 +/- 0.8 minutes, consistent with a previously identified photometric orbital period, and significantly below the normal CV period minimum. This indicates that the donor in SBSS 1108+574 is highly evolved. The superhump excess derived from our photometry implies a mass r...

Carter, P J; de Miguel, E; Goff, W; Koff, R A; Krajci, T; Marsh, T R; Gänsicke, B T; Breedt, E; Groot, P J; Nelemans, G; Roelofs, G H A; Rau, A; Koester, D; Kupfer, T

2013-01-01T23:59:59.000Z

194

Neutron Irradiation Tests of Pressure Transducers in Liquid Helium  

E-Print Network (OSTI)

The superconducting magnets of the future Large Hadron Collider (LHC) at CERN will operate in pressurised superfluid helium (1 bar, 1.9 K). About 500 pressure transducers will be placed in the liquid helium bath for monitoring the filling and the pressure transients after resistive transitions. Their precision must remain better than 100 mbar at pressures below 2 bar and better than 5% for higher pressures (up to 20 bar), with temperatures ranging from 1.8 K to 300 K. All the tested transducers are based on the same principle: the fluid or gas is separated from a sealed reference vacuum by an elastic membrane; its deformation indicates the pressure. The transducers will be exposed to high neutron fluence (2 kGy, 1014 n/cm2 per year) during the 20 years of machine operation. This irradiation may induce changes both on the membranes characteristics (leakage, modification of elasticity) and on gauges which measure their deformations. To investigate these effects and select the transducer to be used in the LHC, a...

Amand, J F; Casas-Cubillos, J; Thermeau, J P

1999-01-01T23:59:59.000Z

195

Ignition and extinction phenomena in helium micro hollow cathode discharges  

SciTech Connect

Micro hollow cathode discharges (MHCD) were produced using 250??m thick dielectric layer of alumina sandwiched between two nickel electrodes of 8??m thickness. A through cavity at the center of the chip was formed by laser drilling technique. MHCD with a diameter of few hundreds of micrometers allowed us to generate direct current discharges in helium at up to atmospheric pressure. A slowly varying ramped voltage generator was used to study the ignition and the extinction periods of the microdischarges. The analysis was performed by using electrical characterisation of the V-I behaviour and the measurement of He*({sup 3}S{sub 1}) metastable atoms density by tunable diode laser spectroscopy. At the ignition of the microdischarges, 2??s long current peak as high as 24?mA was observed, sometimes followed by low amplitude damped oscillations. At helium pressure above 400?Torr, an oscillatory behaviour of the discharge current was observed just before the extinction of the microdischarges. The same type of instability in the extinction period at high pressure also appeared on the density of He*({sup 3}S{sub 1}) metastable atoms, but delayed by a few ?s relative to the current oscillations. Metastable atoms thus cannot be at the origin of the generation of the observed instabilities.

Kulsreshath, M. K.; Schwaederle, L.; Dufour, T.; Lefaucheux, P.; Dussart, R. [GREMI, CNRS/Université d'Orléans (UMR7344), Orléans (France); Sadeghi, N. [LIPhy, CNRS and Universite Joseph Fourier (UMR5588), Grenoble (France); Overzet, L. J. [GREMI, CNRS/Université d'Orléans (UMR7344), Orléans (France); PSAL, UTDallas, Richardson, Texas 75080-3021 (United States)

2013-12-28T23:59:59.000Z

196

The Source of the Helium Visible Lines in Eta Carinae  

E-Print Network (OSTI)

We assume that the helium-I lines emitted by the massive binary system Eta Carinae are formed in the acceleration zone of the less-massive secondary star. We calculate the Doppler shift of the lines as a function of orbital phase and of several parameters of the binary system. We find that a good fit is obtained if the helium lines are formed in the region where the secondary wind speed is 430 km/sec. The acceptable binary eccentricity is in the range 0.9-0.95, and the inclination angle (the angle between a line perpendicular to the orbital plane and the line of sight) is in the range 40-55 degrees. Lower values of e require higher values of i, and vice versa. The binary system is oriented such that the secondary star is in our direction (closer to us) during periastron passage. The orbital motion can account in part to the Doppler shift of the peak in X-ray emission.

Amit Kashi; Noam Soker

2007-02-25T23:59:59.000Z

197

The Source of the Helium Visible Lines in Eta Carinae  

E-Print Network (OSTI)

We assume that the helium-I lines emitted by the massive binary system Eta Carinae are formed in the acceleration zone of the less-massive secondary star. We calculate the Doppler shift of the lines as a function of orbital phase and of several parameters of the binary system. We find that a good fit is obtained if the helium lines are formed in the region where the secondary wind speed is 430 km/sec. The acceptable binary eccentricity is in the range 0.9-0.95, and the inclination angle (the angle between a line perpendicular to the orbital plane and the line of sight) is in the range 40-55 degrees. Lower values of e require higher values of i, and vice versa. The binary system is oriented such that the secondary star is in our direction (closer to us) during periastron passage. The orbital motion can account in part to the Doppler shift of the peak in X-ray emission.

Kashi, A; Kashi, Amit; Soker, Noam

2007-01-01T23:59:59.000Z

198

Technical Report No.7, Investigation of radon and helium as possible fluid-phase precursors to earthquakes. Technical Report No. 2, Additional task: Radon, helium and geochemical monitoring on the Palmdale uplift.  

E-Print Network (OSTI)

Imperial Valley) HELIUM AND All with RADON IN WELL SAMPLES of the wells in the Southern Network are geothermal

Craig, H; Lupton, J E; Chung, Y; Horowitz, R M

1977-01-01T23:59:59.000Z

199

Faraday and Cotton-Mouton Effects of Helium at = 1064 nm A. Cad`ene1  

E-Print Network (OSTI)

Faraday and Cotton-Mouton Effects of Helium at = 1064 nm A. Cad`ene1 , D. Sordes1 , P. Berceau1 of the Faraday and the Cotton-Mouton effects of helium gas at = 1064 nm. Our apparatus is based on an up and Cotton-Mouton effect. Our measurements give for the first time the experimental value of the Faraday

Paris-Sud XI, Université de

200

Difference in formation of hydrogen and helium clusters in tungsten K. O. E. Henriksson,a  

E-Print Network (OSTI)

Difference in formation of hydrogen and helium clusters in tungsten K. O. E. Henriksson,a K online 12 October 2005 The experimentally observed large difference in the depths of hydrogen and helium and He embrittlement of materials. Yet many of the basic properties of such systems are not well

Krasheninnikov, Arkady V.

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

The Solar Wind Helium Abundance: Variation with Wind Speed and the Solar Cycle  

E-Print Network (OSTI)

The Solar Wind Helium Abundance: Variation with Wind Speed and the Solar Cycle Matthias R. Aellig Alamos National Lab., Los Alamos, NM 87545 Abstract We investigate the helium abundance in the solar wind of 1994 and early 2000 are analyzed. In agreement with similar work for previous solar cycles, we find

Richardson, John

202

Cryogenic (<20 K) helium cooling mitigates radiation damage to protein crystals  

Science Journals Connector (OSTI)

Comparison of diffraction data collected from matched protein crystals bathed in helium at a set temperature of 8 K and nitrogen at 100 K indicate that the use of cryogenic helium can increase the diffractive lifetime of crystals and measurably mitigate radiation damage.

Chinte, U.

2007-03-16T23:59:59.000Z

203

Activation of the liquid helium contamination during its passage in the Collider ring  

SciTech Connect

Radioactivation of possible contamination of the liquid helium trapped in the arcs of the Collider ring of the Superconducting Super Collider and transported by the liquid helium is estimated. This estimation is used to calculate the dose rate on the filter of the refrigerator plant located at the top of the shaft.

Lopez, G.

1994-01-01T23:59:59.000Z

204

Comparison Between Air and Helium for Use as Working Fluids in the Energy-Conversion Cycle of the MPBR  

E-Print Network (OSTI)

A comparison between air and helium for use as working fluids in the energy-conversion cycle of the MPBR is presented. To date, helium has been selected in the MPBR indirect-cycle working reference design. Air open- and ...

Galen, T. A.

205

Helium Refrigerator Liquid Nitrogen Pre-Cooler Component Parameter Sensitivity Analysis  

SciTech Connect

For helium refrigerators using liquid nitrogen (LN) pre-cooling it is not uncommon for the ambient helium refrigeration return stream(s) exiting the cold box to be significantly colder and for the cycle to use more nitrogen than estimated by the process studies. Often there is an emphasis on the length of 300 to 80-K helium-nitrogen heat exchangers to ensure the exiting nitrogen is as close to ambient as possible. However, it is really the size and flow distribution of the 300 to 80-K helium-helium heat exchangers which are the dominate influence of the nitrogen consumption. As such, an analysis was done to identify and quantify the sensitivity the key parameters in the refrigerator LN pre-cooler section affecting the LN consumption.

Peter Knudsen, Venkatarao Ganni

2010-04-01T23:59:59.000Z

206

The Initiation and Propagation of Helium Detonations in White Dwarf Envelopes  

E-Print Network (OSTI)

Detonations in helium-rich envelopes surrounding white dwarfs have garnered attention as triggers of faint thermonuclear ".Ia" supernovae and double detonation Type Ia supernovae. However, recent studies have found that the minimum size of a hotspot that can lead to a helium detonation is comparable to, or even larger than, the white dwarf's pressure scale height, casting doubt on the successful ignition of helium detonations in these systems. In this paper, we examine the previously neglected effects of C/O pollution and a full nuclear reaction network, and we consider hotspots with spatially constant pressure in addition to constant density hotspots. We find that the inclusion of these effects significantly decreases the minimum hotspot size for helium-rich detonation ignition, making detonations far more plausible during turbulent shell convection or during double white dwarf mergers. The increase in burning rate also decreases the minimum shell mass in which a helium detonation can successfully propagate ...

Shen, Ken J

2014-01-01T23:59:59.000Z

207

AVLIS enrichment of medical isotopes  

SciTech Connect

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

208

The Transformation of the Nitrogen Isotope of Mass 15 into Carbon and Helium by Bombardment with Protons  

Science Journals Connector (OSTI)

...proton width of the maximum is 250 eV. Extrapolation of the one-level dispersion formula, together with the theory of thermonuclear reactions, gives a lifetime of 3 10 years for N in the sun. A photographic method of determining the angular distribution...

1949-01-01T23:59:59.000Z

209

A systematic regional trend in helium isotopes across the northern basin and range province, Western North America  

E-Print Network (OSTI)

high potential for geothermal energy development. Over thespring; CF: Cove Fort geothermal energy plant. Additionalspring; CF: Cove Fort geothermal energy plant. Additional

Kennedy, B. Mack; van Soest, Matthijs C.

2006-01-01T23:59:59.000Z

210

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

211

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

212

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

DOE Data Explorer (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.

213

The helium-core mass at the helium flash in low-mass red giant stars observations and theory  

E-Print Network (OSTI)

The method developed by Raffelt (1990a,b,c) to estimate a possible increase in the standard values of the helium-core mass at the tip of the red giant branch, \\Mc, from properties of the color-magnitude diagrams of Galactic globular clusters is employed. In the present study, we revise and update Raffelt's database, including also constraints from RR Lyrae pulsation, and find that a small increase, by \\Delta\\Mc \\approx 0.01\\pm 0.015 \\Msun, cannot be ruled out with the present data and evolutionary models. Our new upper limits on \\Delta\\Mc are less restrictive than those previously obtained by Raffelt, as are the corresponding constraints on novel astroparticle phenomena which may affect the evolution of low-mass red giants. Within the estimated uncertainties, however, the standard values of \\Mc may also be acceptable. Raffelt's method does not rule out a low envelope helium abundance in globular cluster giants, though again the standard values are compatible with the available constraints. The influence of a ...

Catelan, M

1995-01-01T23:59:59.000Z

214

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

215

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

216

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

217

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

218

An MCMC determination of the primordial helium abundance  

SciTech Connect

Spectroscopic observations of the chemical abundances in metal-poor H II regions provide an independent method for estimating the primordial helium abundance. H II regions are described by several physical parameters such as electron density, electron temperature, and reddening, in addition to y, the ratio of helium to hydrogen. It had been customary to estimate or determine self-consistently these parameters to calculate y. Frequentist analyses of the parameter space have been shown to be successful in these parameter determinations, and Markov Chain Monte Carlo (MCMC) techniques have proven to be very efficient in sampling this parameter space. Nevertheless, accurate determination of the primordial helium abundance from observations of H II regions is constrained by both systematic and statistical uncertainties. In an attempt to better reduce the latter, and continue to better characterize the former, we apply MCMC methods to the large dataset recently compiled by Izotov, Thuan, and Stasi?ska (2007). To improve the reliability of the determination, a high quality dataset is needed. In pursuit of this, a variety of cuts are explored. The efficacy of the He I ?4026 emission line as a constraint on the solutions is first examined, revealing the introduction of systematic bias through its absence. As a clear measure of the quality of the physical solution, a ?{sup 2} analysis proves instrumental in the selection of data compatible with the theoretical model. Nearly two-thirds of the observations fall outside a standard 95% confidence level cut, which highlights the care necessary in selecting systems and warrants further investigation into potential deficiencies of the model or data. In addition, the method also allows us to exclude systems for which parameter estimations are statistical outliers. As a result, the final selected dataset gains in reliability and exhibits improved consistency. Regression to zero metallicity yields Y{sub p} = 0.2534 ± 0.0083, in broad agreement with the WMAP result. The inclusion of more observations shows promise for further reducing the uncertainty, but more high quality spectra are required.

Aver, Erik; Olive, Keith A.; Skillman, Evan D., E-mail: aver@physics.umn.edu, E-mail: olive@umn.edu, E-mail: skillman@astro.umn.edu [School of Physics and Astronomy, University of Minnesota, 116 Church St. SE, Minneapolis, MN 55455 (United States)

2012-04-01T23:59:59.000Z

219

Gas Turbine Manufacturers Perspective  

NLE Websites -- All DOE Office Websites (Extended Search)

Viability and Experience of IGCC From a Viability and Experience of IGCC From a Gas Turbine Manufacturers Perspective ASME - IGCC ASME - IGCC Turbo Turbo Expo Expo June 2001 June 2001 GE Power Systems g Klaus Brun, Ph.D. - Manager Process Power Plant Product & Market Development Robert M. Jones - Project Development Manager Process Power Plants Power Systems Power Systems General Electric Company General Electric Company ABSTRACT GE Power Systems g Economic Viability and Experience of IGCC From a Gas Turbine Manufacturers Perspective High natural gas fuel gas prices combined with new technology developments have made IGCC a competitive option when compared to conventional combined cycle or coal steam turbine cycles. Although the initial investment costs for an IGCC plant are still comparatively high, the low

220

Zeeman deceleration of electron-impact-excited metastable helium atoms  

E-Print Network (OSTI)

We present experimental results that demonstrate - for the first time - the Zeeman deceleration of helium atoms in the metastable 2^3S_1state. A more than 40% decrease of the kinetic energy of the beam is achieved for deceleration from 490 m/s to a final velocity of 370 m/s. Metastable atom generation is achieved with an electron-impact-excitation source whose performance is enhanced through an additional discharge-type process which we characterize in detail. Comparison of deceleration data at different electron beam pulse durations confirms that a matching between the initial particle distribution and the phase-space acceptance of the decelerator is crucial for the production of a decelerated packet with a well-defined velocity distribution. The experimental findings are in good agreement with three-dimensional numerical particle trajectory simulations.

Dulitz, Katrin; Softley, Timothy P

2015-01-01T23:59:59.000Z

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

Options for Cryogenic Load Cooling with Forced Flow Helium Circulation  

SciTech Connect

Cryogenic pumps designed to circulate super-critical helium are commonly deemed necessary in many super-conducting magnet and other cooling applications. Acknowledging that these pumps are often located at the coldest temperature levels, their use introduces risks associated with the reliability of additional rotating machinery and an additional load on the refrigeration system. However, as it has been successfully demonstrated, this objective can be accomplished without using these pumps by the refrigeration system, resulting in lower system input power and improved reliability to the overall cryogenic system operations. In this paper we examine some trade-offs between using these pumps vs. using the refrigeration system directly with examples of processes that have used these concepts successfully and eliminated using such pumps

Peter Knudsen, Venkatarao Ganni, Roberto Than

2012-06-01T23:59:59.000Z

222

Friction-Induced Fluid Heating in Nanoscale Helium Flows  

SciTech Connect

We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.

Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

2010-05-21T23:59:59.000Z

223

Design of oilfree all turbo-type helium refrigerator  

Science Journals Connector (OSTI)

We have designed a high efficient, compact 300 W oilfree all turbo-type heliumrefrigerator capable of long maintenance free continuous operation. The main compressor at ambient temperature which is driven by a helium gas turbine attached to the same shaft, is supported by magnetic bearings, and, has an inlet and outlet pressure of 0.35 \\{MPa\\} and 0.7 MPa. Four turbo expanders are employed, including one at 80 K because LN2 is not used in this system. Each expander drives a cold compressor, accompanying a generator brake by use of an induction motor. This provides very easy control. Variable nozzles are adopted to the expanders, and the number of valves are diminished as much as possible to reduce line pressure loss. Concerning a heat exchanger, we have examined a micro tube laminar flow heat exchanger which is compact and enables high efficiency at low temperature. This heat exchanger can reduce pressure loss greatly.

N. Saji; S. Nagai; H. Asakura; Y. Kaneko

1994-01-01T23:59:59.000Z

224

Equation of state and optical properties of warm dense helium  

Science Journals Connector (OSTI)

We investigate the physical properties of warm dense helium under the conditions found in the atmospheres of cool white dwarfs using both a chemical model and ab initio simulations. A chemical model is developed for the low-ionization limit that includes the species He, He+, He2+, and electrons, and interactions between them. The ab initio calculations consist in quantum molecular dynamics (QMD) simulations. We use the generalized gradient approximation (GGA) to calculate the equation of state and the electrical and optical properties within the linear response theory. We further use an exact exchange hybrid (PBE0) density functional as well as the GW approximation to estimate the uncertainties on the electrical and optical properties resulting from the GGA approximation. While both the chemical model and the QMD simulations are in excellent agreement with the measured equation of state, a qualitative discrepancy exists with the measured conductivity.

P. M. Kowalski, S. Mazevet, D. Saumon, and M. Challacombe

2007-08-10T23:59:59.000Z

225

The Role of Helium in the Outer Solar Atmosphere  

Science Journals Connector (OSTI)

We construct models of the outer solar atmosphere comprising the region from the mid-chromosphere and into the solar wind in order to study the force and energy balance in models with a significant helium abundance. The corona is created by dissipation of an energy flux from the Sun. The energy flux is lost as radiation from the top of the chromosphere and as gravitational and kinetic solar wind energy flux. We find that in models with significant ion heating of the extended corona most of the energy flux is lost in the solar wind. The ion temperatures are higher than the electron temperature in these models, and the ?-particle temperature is much higher than the proton temperature, so there is energy transfer from the ?-particle fluid to the protons and electrons, but this energy exchange between the different species is relatively small. To a fairly good approximation we can say that the energy flux deposited in the protons and ?-particles is lost as kinetic and gravitational energy flux in the proton and ?-particle flow. How this energy flux is divided between gravitational and kinetic energy flux (i.e., how large the particle fluxes and flow speeds are) depends upon details of the heating process. We also find that mixing processes in the chromosphere play an important role in determining the coronal helium abundance and the relative solar wind proton and ?-particle fluxes. Roughly speaking, we find that the relative ?-particle and proton fluxes are set by the degree of chromospheric mixing, while the speeds are set by the details of the coronal heating process.

V. H. Hansteen; E. Leer; T.

1997-01-01T23:59:59.000Z

226

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

227

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

228

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

229

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

230

THE EFFECTS OF CURVATURE AND EXPANSION ON HELIUM DETONATIONS ON WHITE DWARF SURFACES  

SciTech Connect

Accreted helium layers on white dwarfs have been highlighted for many decades as a possible site for a detonation triggered by a thermonuclear runaway. In this paper, we find the minimum helium layer thickness that will sustain a steady laterally propagating detonation and show that it depends on the density and composition of the helium layer, specifically {sup 12}C and {sup 16}O. Detonations in these thin helium layers have speeds slower than the Chapman-Jouget (CJ) speed from complete helium burning, v{sub CJ} = 1.5 × 10{sup 9} cm s{sup –1}. Though gravitationally unbound, the ashes still have unburned helium (?80% in the thinnest cases) and only reach up to heavy elements such as {sup 40}Ca, {sup 44}Ti, {sup 48}Cr, and {sup 52}Fe. It is rare for these thin shells to generate large amounts of {sup 56}Ni. We also find a new set of solutions that can propagate in even thinner helium layers when {sup 16}O is present at a minimum mass fraction of ?0.07. Driven by energy release from ? captures on {sup 16}O and subsequent elements, these slow detonations only create ashes up to {sup 28}Si in the outer detonated He shell. We close by discussing how the unbound helium burning ashes may create faint and fast 'Ia' supernovae as well as events with virtually no radioactivity, and speculate on how the slower helium detonation velocities impact the off-center ignition of a carbon detonation that could cause a Type Ia supernova in the double detonation scenario.

Moore, Kevin; Bildsten, Lars [Department of Physics, University of California, Santa Barbara, CA (United States); Townsley, Dean M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL (United States)

2013-10-20T23:59:59.000Z

231

Long-term changes in solar wind elemental and isotopic ratios: A compairosn of two lunar ilmenites of different antiquities  

SciTech Connect

An ilmenite separate from lunar regolith breccia 79035, a sample presumed to have been exposed to solar wind more than 2 Ga ago, was analyzed for noble gas and nitrogen elemental and isotopic abundances by stepwise oxidation and pyrolysis. The gases appear to be distributed between two distinct reservoirs in the ilmenite, defined by release patterns and isotopic considerations. One of the reservoirs, near grain surfaces, yields elemental ratios that for the most part are solar while the other, sited at greater depths within grains, has severely fractionated elemental abundances and generally heavier isotopic ratios as well. Xenon provides an exception to the solar abundance pattern in the near-surface reservoir, being enhanced by about a factor of 2 relative to the expected value. A comparison of the 79035 separate with a previously analyzed ilmenite from soil 71501, which received its solar wind exposure much more recently, indicates that the two-fold xenon enhancement occurs in the fractionated reservoir as well as the solar one, and that it may therefore be attributable to a change in the solar wind elemental abundances. Other differences between the two ilmenites occur in helium and neon isotopic ratios and in He/Ar elemental ratios. Since mineralogical influences on retentivities of the gases in the two samples should be the same, and possible contributions of non-solar wind components to one ilmenite in preference to the other can generally be eliminated or accounted for, all of these differences may reflect changes in the solar wind over time.

Becker, R.H.; Pepin, R.O. (Univ. of Minneapolis, MN (USA))

1989-05-01T23:59:59.000Z

232

The effect of a micro bubble dispersed gas phase on hydrogen isotope transport in liquid metals under nuclear irradiation  

E-Print Network (OSTI)

The present work intend to be a first step towards the understanding and quantification of the hydrogen isotope complex phenomena in liquid metals for nuclear technology. Liquid metals under nuclear irradiation in,e.g., breeding blankets of a nuclear fusion reactor would generate tritium which is to be extracted and recirculated as fuel. At the same time that tritium is bred, helium is also generated and may precipitate in the form of nano bubbles. Other liquid metal systems of a nuclear reactor involve hydrogen isotope absorption processes, e.g., tritium extraction system. Hence, hydrogen isotope absorption into gas bubbles modelling and control may have a capital importance regarding design, operation and safety. Here general models for hydrogen isotopes transport in liquid metal and absorption into gas phase, that do not depend on the mass transfer limiting regime, are exposed and implemented in OpenFOAMR CFD tool for 0D to 3D simulations. Results for a 0D case show the impact of a He dispersed phase of na...

Fradera, Jorge

2013-01-01T23:59:59.000Z

233

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

234

50 years of helium liquefaction at the MIT Cryogenic Engineering Laboratory  

Science Journals Connector (OSTI)

The evolution of the helium liquefaction facility of the MIT Cryogenic Engineering Laboratory and the history of its operation over the last 50 years are described. Professor Samuel C. Collins created the liquid-helium facility based on his earlier developments. The chronology of the laboratory helium liquefiers is given with a brief description of each one. The current facility based on the Model 2000 liquefier is described and operating experience is given. The reasons for the very high availability of the liquefaction system are developed.

Joseph L. Smith Jr.

2002-01-01T23:59:59.000Z

235

Helium effects on the mechanical properties of neutron-irradiated Cr-Mo ferritic steels  

SciTech Connect

In the first wall of a fusion rector, large amounts of transmutation helium will be produced simultaneously with the displacement damage caused by high-energy neutrons from the fusion reaction. One method used to simulate irradiation effects for ferritic steels is to add nickel to the steels and irradiate them in a mixed-spectrum reactor. Fast neutrons in the spectrum produce displacement damage, while transmutation helium is produced by a two-step reaction of {sup 58}Ni with thermal neutrons. This technique has been used to investigate the effect of helium on tensile properties and toughness. Results from these studies are summarized.

Klueh, R.L.

1990-01-01T23:59:59.000Z

236

Laser-driven nanoplasmas in doped helium droplets: Local ignition and anisotropic expansion  

E-Print Network (OSTI)

Doping a helium nanodroplet with a tiny xenon cluster of a few atoms only, sparks complete ionization of the droplet at laser intensities below the ionization threshold of helium atoms. As a result, the intrinsically inert and transparent droplet turns into a fast and strong absorber of infrared light. Microscopic calculations reveal a two-step mechanism to be responsible for the dramatic change: Avalanche-like ionization of the helium atoms on a femtosecond time scale, driven by field ionization due to the quickly charged xenon core is followed by resonant absorption enabled by an unusual cigar-shaped nanoplasma within the droplet.

Mikaberidze, Alexey; Rost, Jan M

2009-01-01T23:59:59.000Z

237

Laser-Driven Nanoplasmas in Doped Helium Droplets: Local Ignition and Anisotropic Growth  

Science Journals Connector (OSTI)

Doping a helium nanodroplet with only a tiny xenon cluster of a few atoms sparks complete ionization of the droplet at laser intensities below the ionization threshold of helium atoms. As a result, the intrinsically inert and transparent droplet turns into a fast and strong absorber of infrared light. Microscopic calculations reveal a two-step mechanism to be responsible for the dramatic change: Avalanchelike ionization of the helium atoms on a femtosecond time scale, driven by field ionization due to the quickly charged xenon core, is followed by resonant absorption enabled by an unusual cigar-shaped nanoplasma within the droplet.

Alexey Mikaberidze, Ulf Saalmann, and Jan M. Rost

2009-03-25T23:59:59.000Z

238

Perspectives on Energy Efficiency | Department of Energy  

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

Perspectives on Energy Efficiency Perspectives on Energy Efficiency Presentation on EE policies, industry examples, efficiency ratings for home, and ISO 50001....

239

Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems  

SciTech Connect

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

240

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

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

Perspective: Nonadiabatic dynamics theory  

Science Journals Connector (OSTI)

Nonadiabatic dynamics—nuclear motion evolving on multiple potential energy surfaces—has captivated the interest of chemists for decades. Exciting advances in experimentation and theory have combined to greatly enhance our understanding of the rates and pathways of nonadiabatic chemical transformations. Nevertheless there is a growing urgency for further development of theories that are practical and yet capable of reliable predictions driven by fields such as solar energy interstellar and atmospheric chemistry photochemistry vision single molecule electronics radiation damage and many more. This Perspective examines the most significant theoretical and computational obstacles to achieving this goal and suggests some possible strategies that may prove fruitful.

John C. Tully

2012-01-01T23:59:59.000Z

242

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

243

On the mechanism of electromagnetic microwave absorption in superfluid helium  

SciTech Connect

In experiments on electromagnetic (EM) wave absorption in the microwave range in superfluid (SF) helium [1-3], a narrow EM field absorption line with a width on the order of (20-200) kHz was observed against the background of a wide absorption band with a width of 30-40 GHz at frequencies f{sub 0} Almost-Equal-To 110-180 GHz corresponding to the roton gap energy {Delta}{sub r}(T) in the temperature range 1.4-2.2 K. Using the so-called flexoelectric mechanism of polarization of helium atoms ({sup 4}He) in the presence of density gradients in SF helium (HeII), we show that nonresonance microwave absorption in the frequency range 170-200 GHz can be due to the existence of time-varying local density gradients produced by roton excitations in the bulk HeII. The absorption bandwidth is determined by the roton-roton scattering time in an equilibrium Boltzmann gas of rotons, which is t{sub r-r} Almost-Equal-To 3.4 Multiplication-Sign 10{sup -11} s at T = 1.4 K and decreases upon heating. We propose that the anomalously narrow microwave resonance absorption line in HeII at the roton frequency f{sub 0}(T) = {Delta}r(T)/2{pi}h appears due to the following two factors: (i) the discrete structure of the spectrum of the surface EM resonator modes in the form of a periodic sequence of narrow peaks and (ii) the presence of a stationary dipole layer in HeII near the resonator surface, which forms due to polarization of {sup 4}He atoms under the action of the density gradient associated with the vanishing of the density of the SF component at the solid wall. For this reason, the relaxation of nonequilibrium rotons generated in such a surface dipole layer is strongly suppressed, and the shape and width of the microwave resonance absorption line are determined by the roton density of states, which has a sharp peak at the edge of the roton gap in the case of weak dissipation. The effective dipole moments of rotons in the dipole layer can be directed either along or across the normal to the resonator surface, which explains the experimentally observed symmetric doublet splitting of the resonance absorption line in an external dc electric field perpendicular to the resonator surface. We show that negative absorption (induced emission) of EM field quanta observed after triggering a Kapitza 'heat gun' occurs when the occupation numbers for roton states due to 'pumping' of rotons exceed the occupation numbers of EM field photons in the resonator.

Pashitskii, E. A., E-mail: pashitsk@iop.kiev.ua; Pentegov, V. I. [National Academy of Sciences of Ukraine, Institute of Physics (Ukraine)

2012-08-15T23:59:59.000Z

244

Magnesium Isotopes in Halo Stars  

E-Print Network (OSTI)

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

Jorge Melendez; Judith G. Cohen

2007-08-29T23:59:59.000Z

245

Direct Detection of Vacuum Ultraviolet Radiation for Nonmetal Determinations with a Helium Microwave-Induced Plasma  

Science Journals Connector (OSTI)

A study of the determination of metals, nonmetals, and metalloids (F, Cl, Br, I, S, P, Se, As, Sb, and Pb) in the vacuum-ultraviolet spectral region with a kilowatt-plus helium...

Alvarado, Jorge; Carnahan, Jon W

1993-01-01T23:59:59.000Z

246

High-frequency two-photon ionization of helium and cesium  

Science Journals Connector (OSTI)

Calculations of the two-photon ionization of metastable levels of helium and the first three s levels of cesium are presented. The calculations are carried out to second order in a...

Marinescu, M; Sadeghpour, H R; Dalgarno, A

1993-01-01T23:59:59.000Z

247

Modeling the point-spread function in helium-ion lithography  

E-Print Network (OSTI)

We present here a hybrid approach to modeling helium-ion lithography that combines the power and ease-of-use of the Stopping and Range of Ions in Matter (SRIM) software with the results of recent work simulating secondary ...

Winston, Donald

248

Development of Small Size Claude Cycle Helium Refrigerator with Micro Turbo-Expander  

Science Journals Connector (OSTI)

In the field of small size helium refrigerators, need for a maintenance free and vibration free system is rapidly increasing, especially for the application to cryoelectronic devices such as NMR-CT and Josephs...

H. Izumi; S. Harada; K. Matsubara; S. Saito

1986-01-01T23:59:59.000Z

249

Products of High-Energy Deuteron and Helium Ion Bombardments of Copper  

E-Print Network (OSTI)

AND HELIUM ION BOHBARDMENTS OF COPPER D. R. Miller, R. C.observations made when natural copper (stable mass numbersof the Bombardment of Natural Copper with 190 Mev Deuterons

Miller, D.R.

2010-01-01T23:59:59.000Z

250

Conception design of helium ion FFAG accelerator with induction accelerating cavity  

E-Print Network (OSTI)

In the recent decades of particle accelerator R&D area, fixed field alternating gradient (FFAG) accelerator has become a highlight for some advantages of its higher beam intensity and lower cost, although there are still some technical challenges. In this paper, FFAG accelerator is adopted to accelerate helium ion beam on the one hand for the study of helium embrittlement on fusion reactor envelope material and on the other hand for promoting the conception research and design of FFAG accelerator and exploring the possibility of developing high power FFAG accelerators. The conventional period focusing unit of helium ion FFAG accelerator and three-dimensional model of the large aperture combinatorial magnet by OPERA-TOSCA are given. For low energy and low revolution frequency, induction acceleration is proposed to replace conventional radio frequency(RF) acceleration for helium ion FFAG accelerator, which avoids the potential breakdown of acceleration field caused by wake field and improves the acceleratio...

Huan-li, Luo; Xiang-qi, Wang; Hong-Liang, Xu

2013-01-01T23:59:59.000Z

251

CONDITIONS FOR SUCCESSFUL HELIUM DETONATIONS IN ASTROPHYSICAL ENVIRONMENTS  

SciTech Connect

Several models for Type Ia-like supernova events rely on the production of a self-sustained detonation powered by nuclear reactions. In the absence of hydrogen, the fuel that powers these detonations typically consists of either pure helium (He) or a mixture of carbon and oxygen (C/O). Studies that systematically determine the conditions required to initiate detonations in C/O material exist, but until now no analogous investigation of He matter has been conducted. We perform one-dimensional reactive hydrodynamical simulations at a variety of initial density and temperature combinations and find critical length scales for the initiation of He detonations that range between 1 and 10{sup 10} cm. A simple estimate of the length scales over which the total consumption of fuel will occur for steady-state detonations is provided by the Chapman-Jouguet (CJ) formalism. Our initiation lengths are consistently smaller than the corresponding CJ length scales by a factor of {approx}100, providing opportunities for thermonuclear explosions in a wider range of low-mass white dwarfs (WDs) than previously thought possible. We find that virialized WDs with as little mass as 0.24 M{sub Sun} can be detonated, and that even less massive WDs can be detonated if a sizable fraction of their mass is raised to a higher adiabat. That the initiation length is exceeded by the CJ length implies that certain systems may not reach nuclear statistical equilibrium within the time it takes a detonation to traverse the object. In support of this hypothesis, we demonstrate that incomplete burning will occur in the majority of He WD detonations and that {sup 40}Ca, {sup 44}Ti, or {sup 48}Cr, rather than {sup 56}Ni, is the predominant burning product for many of these events. We anticipate that a measure of the quantity of the intermediate-mass elements and {sup 56}Ni produced in a helium-rich thermonuclear explosion can potentially be used to constrain the nature of the progenitor system.

Holcomb, Cole; Guillochon, James; De Colle, Fabio; Ramirez-Ruiz, Enrico [TASC, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

2013-07-01T23:59:59.000Z

252

Background - Historical Perspective  

NLE Websites -- All DOE Office Websites (Extended Search)

Historical Perspective Historical Perspective The Highway Trust Fund (HTF) was established in 1956 (Public Law 84-627) to ensure a dependable source of Federal funding to support highway programs. Prior to 1956, motor fuel and vehicle taxes went to the General Fund; although highway funding was provided from the General Fund, there was no relationship between fuel tax receipts and highway funding. Since 1956, legislation has periodically extended taxation of motor fuels and the HTF. The Transportation Equity Act for the 21st Century (TEA-21) extended the HTF through September 30, 2005. The HTF currently contains two accounts: the Highway Account and the Mass Transit Account; this document only concerns funds in the Highway Account. The income and outlays for transportation have increased steadily over time. The closing balance of funds in the Highway Account of the HTF remained at around $10 billion from 1983 through 1995. In 2000, the closing balance in the Highway Account was over $22.5 billion. It is necessary to maintain a balance of funds in the HTF to be able to meet unpaid commitments. This balance is not surplus funds because the HTF functions as a reimbursable program and must maintain funds for reimbursing obligations. The closing balance (income - outlays = closing balance) is shown in the following chart for 1957 through 2000 (the latest available data).

253

Maximum Reasonable Radioxenon Releases from Medical Isotope Production Facilities and Their Effect on Monitoring Nuclear Explosions  

SciTech Connect

Fission gases such as 133Xe are used extensively for monitoring the world for signs of nuclear testing in systems such as the International Monitoring System (IMS). These gases are also produced by nuclear reactors and by fission production of 99Mo for medical use. Recently, medical isotope production facilities have been identified as the major contributor to the background of radioactive xenon isotopes (radioxenon) in the atmosphere (Saey, et al., 2009). These releases pose a potential future problem for monitoring nuclear explosions if not addressed. As a starting point, a maximum acceptable daily xenon emission rate was calculated, that is both scientifically defendable as not adversely affecting the IMS, but also consistent with what is possible to achieve in an operational environment. This study concludes that an emission of 5×109 Bq/day from a medical isotope production facility would be both an acceptable upper limit from the perspective of minimal impact to monitoring stations, but also appears to be an achievable limit for large isotope producers.

Bowyer, Ted W. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Kephart, Rosara F.; Eslinger, Paul W. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Friese, Judah I. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Miley, Harry S. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Saey, Paul R. [Vienna University of Technology, Atomic Institute of the Austrian Universities, Vienna (Austria)

2013-01-01T23:59:59.000Z

254

Nuclear Energy Protocol for Research Isotopes Owen Lowe  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

255

Diameters of Single-Wall Carbon Nanotubes Depending on Helium Gas Pressure in an Arc Discharge  

Science Journals Connector (OSTI)

Diameters of Single-Wall Carbon Nanotubes Depending on Helium Gas Pressure in an Arc Discharge ... So far, relatively large quantities of SWNTs have been produced by using Y?Ni and Fe?Ni catalysts for the electric arc discharge method28-30 and by using a Co?Ni catalyst for the pulsed laser ablation method. ... The electric current of the arc discharge also affected the yield of SWNTs though its effect was not as serious as the helium pressure. ...

Yahachi Saito; Yoshihiko Tani; Atsuo Kasuya

2000-02-26T23:59:59.000Z

256

Corrosion behavior of zirconia-coated Hastelloy X in a high-temperature helium environment  

SciTech Connect

The corrosion behavior of Hastelloy X coated with (NiCrAl)/(ZrO/sub 2/-CaC/sub 2/) was examined, after serving as the liner tube of helium engineering demonstration loop (HENDEL) hot gas duct. The Hastelloy X with the ceramic coating system was exposed to high-temperature helium gas for --6000 h. The compositions of oxide films formed on Hastelloy X were entirely different between the noncoated and ceramic-coated tubes.

Kondo, Y.; Fukaya, K.

1989-01-01T23:59:59.000Z

257

Discrete Visible Luminescence of Helium Atoms and Molecules Desorbing from Helium Clusters: The Role of Electronic, Vibrational, and Rotational Energy Transfer  

SciTech Connect

Discrete visible and near-infrared luminescence of a beam of photoexcited helium clusters is reported. The emission lines are attributed to free helium atoms and molecules desorbing from clusters in electronically excited states. Depending on the excitation energy, various atomic and molecular singlet and triplet states are involved in the relaxation process. With increasing cluster size the intensity of molecular transitions becomes dominant. The temperature of ejected molecules could be estimated to T{sub vib}{approximately}2500 K and T{sub rot}{approximately}450 K and is much higher than that of the cluster itself. {copyright} {ital 1997} {ital The American Physical Society}

von Haeften, K.; von Pietrowski, R.; Moeller, T. [Hamburger Synchrotronstrahlungslabor HASYLAB Deutsches Elektronen Synchroton DESY, Hamburg, Notkestr. 85, 22603 Hamburg (Germany)] [Hamburger Synchrotronstrahlungslabor HASYLAB Deutsches Elektronen Synchroton DESY, Hamburg, Notkestr. 85, 22603 Hamburg (Germany); Joppien, M.; Moussavizadeh, L. [II. Institute fuer Experimentalphysik, Universitaet Hamburg (Germany)] [II. Institute fuer Experimentalphysik, Universitaet Hamburg (Germany); de Castro, A.R. [Laboratorio National de Luz Sincrotron, Campinas 13081-90 (Brazil)] [Laboratorio National de Luz Sincrotron, Campinas 13081-90 (Brazil)

1997-06-01T23:59:59.000Z

258

Strategic Isotope Production | ornl.gov  

NLE Websites -- All DOE Office Websites (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.

259

Electromagnetic Isotope Separation Lab (EMIS) | ORNL  

NLE Websites -- All DOE Office Websites (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

260

View from the Bridge: Commercial Vehicle Perspective  

Energy.gov (U.S. Department of Energy (DOE))

Truck manufacturer's perspective on technologies to achieve truck propulsion system efficiency gains

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

A DEEPLY ECLIPSING DETACHED DOUBLE HELIUM WHITE DWARF BINARY  

SciTech Connect

Using Liverpool Telescope+RISE photometry we identify the 2.78 hr period binary star CSS 41177 as a detached eclipsing double white dwarf binary with a 21,100 K primary star and a 10,500 K secondary star. This makes CSS 41177 only the second known eclipsing double white dwarf binary after NLTT 11748. The 2 minute long primary eclipse is 40% deep and the secondary eclipse 10% deep. From Gemini+GMOS spectroscopy, we measure the radial velocities of both components of the binary from the H{alpha} absorption line cores. These measurements, combined with the light curve information, yield white dwarf masses of M{sub 1} = 0.283 {+-} 0.064 M{sub sun} and M{sub 2} = 0.274 {+-} 0.034 M{sub sun}, making them both helium core white dwarfs. As an eclipsing, double-lined spectroscopic binary, CSS 41177 is ideally suited to measuring precise, model-independent masses and radii. The two white dwarfs will merge in roughly 1.1 Gyr to form a single sdB star.

Parsons, S. G.; Marsh, T. R.; Gaensicke, B. T. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Drake, A. J. [California Institute of Technology, 1200 E. California Blvd, CA 91225 (United States); Koester, D. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Kiel (Germany)

2011-07-10T23:59:59.000Z

262

Collisional Thermalization of Hydrogen and Helium in Solar Wind Plasma  

E-Print Network (OSTI)

In situ observations of the solar wind frequently show the temperature of $\\alpha$-particles (fully ionized helium), $T_\\alpha$, to significantly differ from that of protons (ionized hydrogen), $T_p$. Many heating processes in the plasma act preferentially on $\\alpha$-particles, even as collisions among ions act to gradually establish thermal equilibrium. Measurements from the $\\textit{Wind}$ spacecraft's Faraday cups reveal that, at $r=1.0\\ \\textrm{AU}$ from the Sun, the observed values of the $\\alpha$-proton temperature ratio, $\\theta_{\\alpha p} \\equiv T_\\alpha\\,/\\,T_p$ has a complex, bimodal distribution. This study applied a simple model for the radial evolution of $\\theta_{\\alpha p}$ to these data to compute expected values of $\\theta_{\\alpha p}$ at $r=0.1\\ \\textrm{AU}$. These inferred $\\theta_{\\alpha p}$-values have no trace of the bimodality seen in the $\\theta_{\\alpha p}$-values measured at $r=1.0\\ \\textrm{AU}$ but are instead consistent with the actions of the known mechanisms for $\\alpha$-particle p...

Maruca, Bennett A; Sorriso-Valvo, Luca; Kasper, Justin C; Stevens, Michael L

2013-01-01T23:59:59.000Z

263

EFFECT OF TRITIUM AND DECAY HELIUM ON WELDMENT FRACTURE TOUGHNESS  

SciTech Connect

The fracture toughness data collected in this study are needed to assess the long-term effects of tritium and its decay product on tritium reservoirs. The results show that tritium and decay helium have negative effects on the fracture toughness properties of stainless steel and its weldments. The data and report from this study has been included in a material property database for use in tritium reservoir modeling efforts like the Technology Investment Program ''Lifecycle Engineering for Tritium Reservoirs''. A number of conclusions can be drawn from the data: (1) For unexposed Type 304L stainless steel, the fracture toughness of weldments was two to three times higher than the base metal toughness. (2) Tritium exposure lowered the fracture toughness properties of both base metals and weldments. This was characterized by lower J{sub Q} values and lower J-da curves. (3) Tritium-exposed-and-aged base metals and weldments had lower fracture toughness values than unexposed ones but still retained good toughness properties.

Morgan, M; Scott West, S; Michael Tosten, M

2006-09-26T23:59:59.000Z

264

An Atomistic study of Helium Resolution in bcc Iron  

SciTech Connect

The evolution of gas-stabilized bubbles in irradiated materials can be a significant factor in the microstructural processes that lead to mechanical property and dimensional changes in structural materials exposed to high-energy neutrons. Helium generation and accumulation is particularly important under DT fusion irradiation conditions. Although the process of ballistic resolutioning of gas from bubbles has been long-discussed in the literature, there have been few computational studies of this mechanism. Resolutioning could limit bubble growth by ejecting gas atoms back into the metal matrix. A detailed atomistic study of ballistic He resolutioning from bubbles in bcc iron has been carried out using molecular dynamics. A newly-developed Fe-He interatomic potential was employed, with the iron matrix described by the potential of Ackland and co-workers from 1997. The primary variables examined were: irradiation temperature (100 and 600K), iron knock-on atom energy (5 and 20 keV), bubble radius (~0.5 and 1.0 nm), and He-to-vacancy ratio in the bubble (0.25, 0.5 and 1.0) in order to obtain an assessment of this dynamic resolutioning mechanism. The results presented here focus on the 5 keV cascades which indicate a modest, but potentially significant level of He removal by this process.

Stoller, Roger E [ORNL; Stewart, David M [ORNL

2011-01-01T23:59:59.000Z

265

A Miniature Helium Turbo-Expander for Cryogenic Refrigeration Systems  

Science Journals Connector (OSTI)

Publisher Summary This chapter highlights the features of a miniature helium turbo expander for cryogenic refrigeration systems. The Cryogenic Engineering Laboratory of the National Bureau of Standards has investigated the use of small, high speed turbines, supported by gas lubricated journal bearings, in small capacity refrigeration system. Two systems have been studied, one that operates at 4.2 K and another at 30 K. As a result of optimization studies, a 20:1 pressure ratio was used for the 4.2 K system. It is found that although the final low temperature is obtained with an expansion valve, work extraction is necessary for system operation. Refrigeration at 30 K is accomplished by shutting the expansion valve, and leaving the low temperature loop of the system unused. Refrigeration is obtained downstream of the turbine. It is found that for this system, optimization studies indicated best performance at 4:1 pressure ratio. A program was initiated to investigate the performance of a 4:1 pressure ratio turbine for this application. A design goal of 70% was selected from the qualitative reasoning that in larger sizes 80 to 90% was common, but in small machines friction and leakage losses tend to be relatively high.

M.T. NORTON

1965-01-01T23:59:59.000Z

266

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...

267

EIS-0249: Medical Isotopes Production Project  

Energy.gov (U.S. Department of Energy (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.

268

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...

269

Integration of Nontraditional Isotopic Systems Into Reaction...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

270

Science with Beams of Radioactive Isotopes  

NLE Websites -- All DOE Office Websites (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...

271

Integration of Nontraditional Isotopic Systems Into Reaction...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

272

Perspectives on Energy Efficiency  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

2 2 nd U.S.-China Energy Efficiency Forum Dr. Arun Majumdar Director Advanced Research Projects Agency- Energy U.S. Department of Energy May 6, 2011 Berkeley, California Perspectives on Energy Efficiency 2 | U.S. Department of Energy energy.gov Policy Framework R&D - Advance innovative technologies for appliances, equipment, and products - Integrated buildings approaches Market Priming - Pull new products, practices and services into market faster at scale - Technical support to ENERGY STAR / new higher tier Codes & Standards - Leverage market priming and advanced technologies - Broaden coverage and update frequently to capture savings opportunities Increasing Energy Efficiency (Metrics) Number of Unit Sales At least $23B net benefits Over 3.5 quads saved annually Over 2

273

End User Perspective - Industrial  

NLE Websites -- All DOE Office Websites (Extended Search)

Solid State Research Center Solid State Research Center DOE Fuel Cell Portable Power Workshop End User Perspective - Industrial Consumer Electronics Power (< 20-50W) Department of Energy Fuel Cell Portable Power Workshop Jerry Hallmark Manager Energy Technologies Lab Motorola Labs Solid State Research Center DOE Fuel Cell Portable Power Workshop Outline * Energy & Power of Portable Devices * Fuel Cell Applications & Cost * Key Requirements & Challenges * Fuels for Portable Fuel Cells * Fuel Transportation Regulations and Standards * Methanol Fuel Cells - Direct Methanol Fuel Cells - Reformed Methanol Fuel Cells * Technical Challenges 2 Solid State Research Center DOE Fuel Cell Portable Power Workshop Portable Electronics Yearly Energy Usage  :KU 1990 1980  :KU

274

journal Environmental Health Perspectives  

NLE Websites -- All DOE Office Websites (Extended Search)

Pollutant exposures from unvented gas cooking burners A simulation Pollutant exposures from unvented gas cooking burners A simulation based assessment for Southern California journal Environmental Health Perspectives year month abstract p Background Residential natural gas cooking burners NGCBs can emit substantial quantities of pollutants and they are typically used without venting p p Objective Quantify pollutant concentrations and occupant exposures resulting from NGCB use in California homes p p Methods A mass balance model was applied to estimate time dependent pollutant concentrations throughout homes and the exposure concentrations experienced by individual occupants The model was applied to estimate nitrogen dioxide NO2 carbon monoxide CO and formaldehyde HCHO concentrations for one week each in summer and winter for a representative sample

275

Control: A perspective  

Science Journals Connector (OSTI)

Abstract Feedback is an ancient idea, but feedback control is a young field. Nature long ago discovered feedback since it is essential for homeostasis and life. It was the key for harnessing power in the industrial revolution and is today found everywhere around us. Its development as a field involved contributions from engineers, mathematicians, economists and physicists. It is the first systems discipline; it represented a paradigm shift because it cut across the traditional engineering disciplines of aeronautical, chemical, civil, electrical and mechanical engineering, as well as economics and operations research. The scope of control makes it the quintessential multidisciplinary field. Its complex story of evolution is fascinating, and a perspective on its growth is presented in this paper. The interplay of industry, applications, technology, theory and research is discussed.

Karl J. A?ström; P.R. Kumar

2014-01-01T23:59:59.000Z

276

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

277

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

278

DOE Perspectives on Advanced Hydrocarbon-based Biofuels | Department...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

DOE Perspectives on Advanced Hydrocarbon-based Biofuels DOE Perspectives on Advanced Hydrocarbon-based Biofuels Zia Haq, DPA Coordinator, presentation on DOE Perspectives on...

279

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

280

A perspective of generative reuse  

Science Journals Connector (OSTI)

This paper presents a perspective of generative reuse technologies as they have evolved over the last 15 years or so and a discussion of how generative reuse addresses some key reuse problems. Over that time period, a number of different ...

Ted J. Biggerstaff

1998-01-01T23:59:59.000Z

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

Financial crisis : through various perspectives  

E-Print Network (OSTI)

The 2007 financial crisis can be viewed from various perspectives. First, it can be explained in a wider macroeconomic context, for example by looking at the housing bubble. Monetary policy can be explained according to ...

Kim, Joon Hee

2010-01-01T23:59:59.000Z

282

THE HELIUM CONTENT OF GLOBULAR CLUSTERS: NGC 6121 (M4)  

SciTech Connect

In the context of the multiple stellar population scenario in globular clusters, helium (He) has been proposed as a key element to interpret the observed multiple main sequences, subgiant branches, and red giant branches, as well as the complex horizontal branch (HB) morphology. In particular, second-generation stars belonging to the bluer part of the HB are thought to be more He-rich ({Delta}Y = 0.03 or more) but also more Na-rich/O-poor than those located in the redder part that should have Y equal to the cosmological value. Up to now this hypothesis was only partially confirmed in NGC 6752, where stars of the redder zero-age HB showed an He content of Y = 0.25 {+-} 0.01, fully compatible with the primordial He content of the universe, and were all Na-poor/O-rich. Here we study hot blue horizontal branch (BHB) stars in the GC NGC 6121 (M4) to measure their He plus O/Na content. Our goal is to complete the partial results obtained for NGC 6752, focusing our attention on targets located on the bluer part of the HB of M4. We observed six BHB stars using the VLT2/UVES spectroscopic facility. Spectra of signal-to-noise ratio {approx} 150 were obtained and the very weak He line at 5875 A measured for all our targets. We compared this feature with synthetic spectra to obtain He abundances. In addition O, Na, and Fe abundances were estimated. Stars turned out to be all Na-rich and O-poor and to have a homogeneous He content with a mean value of Y = 0.29 {+-} 0.01(random) {+-} 0.01(systematic), which is enhanced by {Delta}Y {approx} 0.04 with respect to the most recent measurements of the primordial He content of the universe (Y {approx} 0.24/0.25). The high He content of blue HB stars in M4 is also confirmed by the fact that they are brighter than red HB stars (RHB). Theoretical models suggest the BHB stars are He-enhanced by {Delta}(Y) = 0.02/0.03 with respect to the RHB stars. The whole sample of stars has a metallicity of [Fe/H] = -1.06 {+-} 0.02 (internal error), in agreement with other studies available in the literature. This is a rare direct measurement of the (primordial) He abundance for stars belonging to the Na-rich/O-poor population of GC stars in a temperature regime where the He content is not altered by sedimentation or extreme mixing as suggested for the hottest, late helium flash HB stars. Our results support theoretical predictions that the Na-rich/O-poor population is also more He-rich than the Na-poor/O-rich generation and that a leading contender for the second parameter is the He abundance.

Villanova, S.; Geisler, D. [Departamento de Astronomia, Casilla 160, Universidad de Concepcion (Chile); Piotto, G. [Dipartimento di Astronomia, Universita di Padova, Vicolo dell'Osservatorio 3, I-35122 Padua (Italy); Gratton, R. G., E-mail: svillanova@astro-udec.cl, E-mail: dgeisler@astro-udec.cl, E-mail: giampaolo.piotto@unipd.it, E-mail: raffaele.gratton@oapd.inaf.it [Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova (Italy)

2012-03-20T23:59:59.000Z

283

Hydrogen and helium traces in type Ib-c supernovae  

E-Print Network (OSTI)

The spectroscopic properties of a selected optical photospheric spectra of core collapse supernovae (CCSNe) are investigated.Special attention is devoted to traces of hydrogen at early phases. The generated spectra are found to match the observed ones reasonably well, including a list of only 23 candidate ions. Guided by SN Ib 1990I, the observed trough near 6300\\AA is attributed to H$\\alpha$ in almost all Type Ib events, although in some objects it becomes too weak to be discernible, especially at later phases. Alternative line identifications are discussed. Differences in the way hydrogen manifests its presence within CCSNe are highlighted. In Type Ib SNe, the H$\\alpha$ contrast velocity (i.e. line velocity minus the photospheric velocity) seems to increase with time at early epochs, reaching values as high as 8000 km s$^{-1}$ around 15-20 days after maximum and then remains almost constant. The derived photospheric velocities, indicate a lower velocity for Type II SNe 1987A and 1999em as compared to SN Ic 1994I and SN IIb 1993J, while Type Ib events display a somewhat larger variation. The scatter, around day 20, is measured to be $\\sim$5000 km s$^{-1}$. Following two simple approaches, rough estimates of ejecta and hydrogen masses are given. A mass of hydrogen of approximately 0.02 $M_\\odot$ is obtained for SN 1990I, while SNe 1983N and 2000H ejected $\\sim$0.008 $M_\\odot$ and $\\sim$0.08 $M_\\odot$ of hydrogen, respectively. SN 1993J has a higher hydrogen mass, $\\sim 0.7$ $M_\\odot$ with a large uncertainty. A low mass and thin hydrogen layer with very high ejection velocities above the helium shell, is thus the most likely scenario for Type Ib SNe. Some interesting and curious issues relating to oxygen lines suggest future investigations.

A. Elmhamdi; I. J. Danziger; D. Branch; B. Leibundgut; E. Baron; R. P. Kirshner

2006-04-04T23:59:59.000Z

284

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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...

285

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

286

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

287

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

288

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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...

289

Stable Isotope, Site-Specific Mass Tagging For Protein Identification  

NLE Websites -- All DOE Office Websites (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...

290

Enriched Stable Isotope Materials and Chemistry | ornl.gov  

NLE Websites -- All DOE Office Websites (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...

291

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

NLE Websites -- All DOE Office Websites (Extended Search)

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

292

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

293

Advanced Mass Spectrometers for Hydrogen Isotope Analyses  

SciTech Connect

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

294

High flux isotope reactor cold source preconceptual design study report  

SciTech Connect

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

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

1995-12-01T23:59:59.000Z

295

Isotopes  

NLE Websites -- All DOE Office Websites (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...

296

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

297

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

298

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

299

Chemical and Isotopic Composition and Gas Concentrations of Ground Water and Surface Water from Selected Sites At and Near the Idaho National Engineering and Environmental Laboratory, Idaho, 1994-97  

SciTech Connect

>From May 1994 through May 1997, the US Geological Survey, in cooperation with the US Department of Energy, collected water samples from 86 wells completed in the Snake River Plain aquifer at and near the Idaho National Engineering and Environmental Laboratory. The samples were analyzed for a variety of chemical constituents including all major elements and 22 trace elements. Concentrations of scandium, yttrium, and the lanthanide series were measured in samples from 11 wells and 1 hot spring. The data will be used to determine the fraction of young water in the ground water. The fraction of young water must be known to calculate the ages of ground water using chlorofluorocarbons. The concentrations of the isotopes deuterium, oxygen-18, carbon-13, carbon-14, and tritium were measured in many ground water, surface-water and spring samples. The isotopic composition will provide clues to the origin and sources of water in the Snake River Plain aquifer. Concentrations ! of helium-3 , helium-4, total helium, and neon were measured in most groundwater samples, and the results will be used to determine the recharge temperature, and to date the ground waters.

E. Busenberg; L. N. Plummer; M. W. Doughten; P. K. Widman; R. C. Bartholomay (USGS)

2000-05-30T23:59:59.000Z

300

It's Elemental - Isotopes of the Element Francium  

NLE Websites -- All DOE Office Websites (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%

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

It's Elemental - Isotopes of the Element Radon  

NLE Websites -- All DOE Office Websites (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

302

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

303

Selected Isotopes for Optimized Fuel Assembly Tags  

SciTech Connect

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

304

Assessment of Embrittlement of VHTR Structural Alloys in Impure Helium Environments  

SciTech Connect

The helium coolant in high-temperature reactors inevitably contains low levels of impurities during steady-state operation, primarily consisting of small amounts of H{sub 2}, H{sub 2}O, CH{sub 4}, CO, CO{sub 2}, and N{sub 2} from a variety of sources in the reactor circuit. These impurities are problematic because they can cause significant long-term corrosion in the structural alloys used in the heat exchangers at elevated temperatures. Currently, the primary candidate materials for intermediate heat exchangers are Alloy 617, Haynes 230, Alloy 800H, and Hastelloy X. This project will evaluate the role of impurities in helium coolant on the stress-assisted grain boundary oxidation and creep crack growth in candidate alloys at elevated temperatures. The project team will: • Evaluate stress-assisted grain boundary oxidation and creep crack initiation and crack growth in the temperature range of 500-850°C in a prototypical helium environment. • Evaluate the effects of oxygen partial pressure on stress-assisted grain boundary oxidation and creep crack growth in impure helium at 500°C, 700°C, and 850°C respectively. • Characterize the microstructure of candidate alloys after long-term exposure to an impure helium environment in order to understand the correlation between stress-assisted grain boundary oxidation, creep crack growth, material composition, and impurities in the helium coolant. • Evaluate grain boundary engineering as a method to mitigate stress-assisted grain boundary oxidation and creep crack growth of candidate alloys in impure helium. The maximum primary helium coolant temperature in the high-temperature reactor is expected to be 850-1,000°C.Corrosion may involve oxidation, carburization, or decarburization mechanisms depending on the temperature, oxygen partial pressure, carbon activity, and alloy composition. These corrosion reactions can substantially affect long-term mechanical properties such as crack- growth rate and fracture toughness, creep rupture, and fatigue. Although there are some studies on the effects of impurities in helium coolant on creep rupture and fatigue strength, very little is known about their effects on creep crack initiation and crack growth rate at elevated temperatures.

Crone, Wendy; Cao, Guoping; Sridhara, Kumar

2013-05-31T23:59:59.000Z

305

DOUBLE-DETONATION SUB-CHANDRASEKHAR SUPERNOVAE: SYNTHETIC OBSERVABLES FOR MINIMUM HELIUM SHELL MASS MODELS  

SciTech Connect

In the double-detonation scenario for Type Ia supernovae, it is suggested that a detonation initiates in a shell of helium-rich material accreted from a companion star by a sub-Chandrasekhar-mass white dwarf. This shell detonation drives a shock front into the carbon-oxygen white dwarf that triggers a secondary detonation in the core. The core detonation results in a complete disruption of the white dwarf. Earlier studies concluded that this scenario has difficulties in accounting for the observed properties of Type Ia supernovae since the explosion ejecta are surrounded by the products of explosive helium burning in the shell. Recently, however, it was proposed that detonations might be possible for much less massive helium shells than previously assumed (Bildsten et al.). Moreover, it was shown that even detonations of these minimum helium shell masses robustly trigger detonations of the carbon-oxygen core (Fink et al.). Therefore, it is possible that the impact of the helium layer on observables is less than previously thought. Here, we present time-dependent multi-wavelength radiative transfer calculations for models with minimum helium shell mass and derive synthetic observables for both the optical and {gamma}-ray spectral regions. These differ strongly from those found in earlier simulations of sub-Chandrasekhar-mass explosions in which more massive helium shells were considered. Our models predict light curves that cover both the range of brightnesses and the rise and decline times of observed Type Ia supernovae. However, their colors and spectra do not match the observations. In particular, their B - V colors are generally too red. We show that this discrepancy is mainly due to the composition of the burning products of the helium shell of the Fink et al. models which contain significant amounts of titanium and chromium. Using a toy model, we also show that the burning products of the helium shell depend crucially on its initial composition. This leads us to conclude that good agreement between sub-Chandrasekhar-mass explosions and observed Type Ia supernovae may still be feasible but further study of the shell properties is required.

Kromer, M.; Sim, S. A.; Fink, M.; Roepke, F. K.; Seitenzahl, I. R.; Hillebrandt, W., E-mail: mkromer@mpa-garching.mpg.d [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, D-85748 Garching (Germany)

2010-08-20T23:59:59.000Z

306

Control of radio-frequency atmospheric pressure argon plasma characteristics by helium gas mixing  

SciTech Connect

The control of plasma characteristics is one of the important issues in many atmospheric pressure plasma applications. In order to accomplish this control, a feasibility study was performed by investigating the role of helium gas in an argon glow plasma that were produced in ambient air by 13.56 MHz radio-frequency power. Optical emission spectroscopy was used to measure rotational temperature and emission spectra acquired between 300 and 840 nm. Based on electrical and optical measurements, parameters such as gas temperature, breakdown voltage, power coupling efficiency, spatial uniformity of rotational temperature, and the sum of the emission intensity were controlled by varying the argon and helium gas mixing ratio. The addition of helium gas (from 0 to 10 lpm) to the argon flow (of 10 lpm) lowered the breakdown voltage (from 430 to 300 V{sub pk}) and the rotational temperature (from 465 to 360 K). However, an excessive addition of helium resulted in a reduction of the spatial uniformity and efficiency of power coupling. When the ratio of helium to argon flow was between 0.3 and 0.5, a high spatial uniformity with a relatively low gas temperature and breakdown voltage was achieved. This suggests that mixing of the supply gas is a useful way of controlling the plasma characteristics that may be utilized for applications with specific required discharge conditions.

Moon, Se Youn; Han, Jewoo; Choe, W. [Department of Physics, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2006-01-15T23:59:59.000Z

307

Estimation of tritium and helium inventory in the tritium handling system in Korea  

SciTech Connect

In Korea, the Wolsong Tritium Removal Facility (WTRF) is under construction to reduce the amount of tritium present in the moderator and coolant of the CANDU type Wolsong nuclear power plants. Recently, a study on the tritium handling system for recovery of the tritium collected from the WTRF was started. Some tritium would enter the steel of the container walls and subsequently decay to helium. This helium can deteriorate the mechanical properties of the material of the tritium handling system. To evaluate the tritium and helium inventory in the stainless steel wall of this system, the time-dependent diffusion equation was developed, solved and the results are presented in this paper. These results were compared to previous work that evaluated the tritium inventory in the stainless steel wall of 50-L tritium containers. Tritium and helium concentration profiles and the corresponding inventories were evaluated with respect to the various parameters such as exposure time, temperature, and partial pressure. After 24 years, the helium inventory in the wall of the tritium handling system exceeds the tritium inventory. (authors)

Yook, D.; Lee, S.; Lee, K. [Dept. of Nuclear Eng., KAIST, 373-1, Kusong-dong, Yusong-gu, Daejon 305-701 (Korea, Republic of); Song, K. M.; Shon, S. H. [KEPRI, 103-16 Munji-Dong, Yuseong-Gu, Daejeon, 305-380 (Korea, Republic of)

2008-07-15T23:59:59.000Z

308

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

309

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

310

HELIUM SHELL DETONATIONS ON LOW-MASS WHITE DWARFS AS A POSSIBLE EXPLANATION FOR SN 2005E  

SciTech Connect

Recently, several Type Ib supernovae (SNe; with the prototypical SN 2005E) have been shown to have atypical properties. These SNe are faint (absolute peak magnitude of {approx} - 15) and fast SNe that show unique composition. They are inferred to have low ejecta mass (a few tenths of a solar mass) and to be highly enriched in calcium, but poor in silicon elements and nickel. These SNe were therefore suggested to belong to a new class of calcium-rich faint SNe explosions. Their properties were proposed to be the result of helium detonations that may occur on helium accreting white dwarfs. In this paper, we theoretically study the scenario of helium detonations and focus on the results of detonations in accreted helium layers on low-mass carbon-oxygen (CO) cores. We present new results from one-dimensional simulations of such explosions, including their light curves and spectra. We find that when the density of the helium layer is low enough the helium detonation produces large amounts of intermediate elements, such as calcium and titanium, together with a large amount of unburnt helium. Alternatively, enough carbon enrichment of the accreted helium as a result of convective undershoot at the early stages of the runaway can avoid the production of iron group elements as the alpha particles are consumed avoiding iron production. Our results suggest that the properties of calcium-rich faint SNe could indeed be consistent with the helium-detonation scenario on small CO cores. Above a certain density (larger CO cores) the detonation leaves mainly {sup 56}Ni and unburnt helium, and the predicted spectrum will unlikely fit the unique features of this class of SNe. Finally, none of our studied models reproduces the bright, fast-evolving light curves of another type of peculiar SNe suggested to originate in helium detonations (SNe 1885A, 1939B, and 2002bj).

Waldman, Roni; Livne, Eli; Glasner, Ami [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Sauer, Daniel [Stockholm University, Department for Astronomy, AlbaNova University Center, 106 91 Stockholm (Sweden); Perets, Hagai [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Mazzali, Paolo [Max-Planck Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching (Germany); Truran, James W. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Gal-Yam, Avishay [Benoziyo Center for Astrophysics, Faculty of Physics, Weizmann Institute of Science, Rehovot 76100 (Israel)

2011-09-01T23:59:59.000Z

311

Heat transfer enhancement on thin wires in superfluid helium forced flows  

E-Print Network (OSTI)

In this paper, we report the first evidence of an enhancement of the heat transfer from a heated wire by an external turbulent flow of superfluid helium. We used a standard Pt-Rh hot-wire anemometer and overheat it up to 21 K in a pressurized liquid helium turbulent round jet at temperatures between 1.9 K and 2.12 K. The null-velocity response of the sensor can be satisfactorily modeled by the counter flow mechanism while the extra cooling produced by the forced convection is found to scale similarly as the corresponding extra cooling in classical fluids. We propose a preliminary analysis of the response of the sensor and show that -contrary to a common assumption- such sensor can be used to probe local velocity in turbulent superfluid helium.

Duri, Davide; Moro, Jean-Paul; Roche, Philippe-Emmanuel; Diribarne, Pantxo

2014-01-01T23:59:59.000Z

312

The role of HeH+ in cool helium rich white dwarfs  

E-Print Network (OSTI)

HeH$^+$ is found to be the dominant positive ion over a wide range of temperatures and densities relevant to helium rich white dwarfs. The inclusion of HeH$^+$ in ionization equilibrium computations increases the abundance of free electrons by a significant factor. For temperatures below 8000 K, He$^-$ free-free absorption is increased by up to a factor of 5, by the inclusion of HeH$^+$. Illustrative model atmospheres and spectral energy distributions are computed, which show that HeH$^+$ has a strong effect upon the density and pressure structure of helium rich white dwarfs with teff < 8000 K. The inclusion of HeH$^+$ significantly reddens spectral energy distributions and broad band color indices for models with Teff < 5500 K. This has serious implications for existing model atmospheres, synthetic spectra and cooling curves for helium rich white dwarfs.

G. J. Harris; A. E. Lynas-Gray; S. Miller; J. Tennyson

2004-11-12T23:59:59.000Z

313

Neutron-induced dpa, transmutations, gas production, and helium embrittlement of fusion materials  

E-Print Network (OSTI)

In a fusion reactor materials will be subjected to significant fluxes of high-energy neutrons. As well as causing radiation damage, the neutrons also initiate nuclear reactions leading to changes in the chemical composition of materials (transmutation). Many of these reactions produce gases, particularly helium, which cause additional swelling and embrittlement of materials. This paper investigates, using a combination of neutron-transport and inventory calculations, the variation in displacements per atom (dpa) and helium production levels as a function of position within the high flux regions of a recent conceptual model for the "next-step" fusion device DEMO. Subsequently, the gas production rates are used to provide revised estimates, based on new density-functional-theory results, for the critical component lifetimes associated with the helium-induced grain-boundary embrittlement of materials. The revised estimates give more optimistic projections for the lifetimes of materials in a fusion power plant co...

Gilbert, M R; Nguyen-Manh, D; Zheng, S; Packer, L W; Sublet, J -Ch

2013-01-01T23:59:59.000Z

314

Isotopic composition of Silurian seawater  

SciTech Connect

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

315

The Evolution of Low Mass Helium Stars towards Supernova Type I Explosion  

E-Print Network (OSTI)

We explore the hypothesis, that helium stars in a certain mass range can evolve to a carbon core explosion similar to what is widely accepted as an explanation for the SN I phenomenon. This should happen when their carbon-oxygen core grows thanks to the helium shell burning above the core. We found that in the mass range of about 1.7-2.2 Msun, indeed this can happen. The main new insight we believe we gained is the crucial importance of an "early" off-center ignition of carbon, which at a later stage prevents the carbon which forms below the helium burning shell and ignites, from burning the carbon all the way to the center. When helium is almost depleted in the convective envelope by the helium burning shell at its bottom, the now super-Chandrasekhar mass carbon-oxygen core contracts, and the residual degenerate carbon at the center is ignited, resulting in a runaway similar to the classical SN I scenario. Since the structure and behavior of the carbon-oxygen core of the helium stars of our interest is very similar to that of a mass accreting carbon-oxygen star, we also thoroughly examined the behavior of carbon-oxygen stars. We discovered that the models which ignite carbon off-center (in the mass range of about 1.05-1.18 Msun, depending on the carbon mass fraction) present an interesting SN I progenitor scenario of their own, since whereas in the standard scenario runaway always takes place at the same density of about 2E9 gr/cm3, in our case, due to the small amount of carbon ignited, we get a whole range of densities from 1E9 up to 6E9 gr/cm3.

Roni Waldman; Zalman Barkat

2006-11-21T23:59:59.000Z

316

Application of JLab 12GeV helium refrigeration system for the FRIB accelerator at MSU  

SciTech Connect

The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system.

Ganni, V.; Knudsen, P.; Arenius, D. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Casagrande, F. [MSU-FRIB, East Lansing, MI 48824 (United States)

2014-01-29T23:59:59.000Z

317

Stopping Cross Sections of Some Hydrocarbon Gases for 40-200-keV Helium Ions  

Science Journals Connector (OSTI)

The stopping cross sections of air, CH4, C2H2, C2H4, C3H8, (CH2)3, and C3H6 have been measured for incident helium ions in the energy range 40 to 200 keV. The data are in good agreement with previous experiment work, and have standard deviations between 2 and 6%. They obey an energy dependence ?=?E12 in accord with the calculation of Lindhard and Scharff. It has been shown that while there is probably an effect due to chemical binding on the helium-ion stopping cross sections of hydrocarbons, this effect is small.

John T. Park

1965-05-31T23:59:59.000Z

318

Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas  

SciTech Connect

In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H{sub 2} from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H{sub 2} in helium recycle gas are less than 1 ppb.

Chu, X. X.; Zhang, D. X.; Qian, Y.; Liu, W. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800 (China); Zhang, M. M.; Xu, D. [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China)

2014-01-29T23:59:59.000Z

319

Ultrasonic attenuation and volume viscosity in liquid argon, nitrogen and helium  

E-Print Network (OSTI)

. Ultrasonic attenuation in liquid nitrogen at 49. 45 Hc/sec ll. Dersity dependence of the volume viscosity in l. iquid nitrogen 12. Density dependence of Qv/&(S in liquid nitrogen 40 13. Ultrasonic attenuation in liquid helium at 4. 20 K 43 14. Ultrasonic... attenuation in liquid helium at 3. 69"K 44 15. Qv in liquid argon and nitrogen as a function of reduced density 51 LIST OF TABLES 1. Data and results for the calculation of volume viscosity in liquid argon 2. Data and results for the calculation of volume...

Singer, James Robert

2012-06-07T23:59:59.000Z

320

Nanometer-scale tunnel formation in metallic glass by helium ion irradiation  

SciTech Connect

We have shown that upon high fluence helium ion irradiation, metallic glass Cu{sub 50}Zr{sub 45}Ti{sub 5} becomes highly porous at the depth of the helium projected range. The resulting porous region is characterized by the formation of a tunnel like structure and self-linkage of nanometer size gas bubbles. Furthermore, the irradiation leads to the formation of nanometer size Cu{sub x}Zr{sub y} crystals that are randomly distributed. The results of this study indicate that the He-filled bubbles have attractive interactions and experience considerable mobility. Movement of the bubbles is believed to be assisted by ballistic collisions.

Shao Lin [Department of Nuclear Engineering, Texas A and M University, College Station, Texas 77843 (United States); Materials Science and Engineering Program, Texas A and M University, College Station, Texas 77843 (United States); Gorman, Brian P. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401 (United States); Aitkaliyeva, Assel [Materials Science and Engineering Program, Texas A and M University, College Station, Texas 77843 (United States); David Theodore, N. [CHD-Fab, Freescale Semiconductor, Inc., Chandler, Arizona 85224 (United States); Xie Guoqiang [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

2012-07-23T23:59:59.000Z

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

The Chemical Evolution of Helium in Globular Clusters: Implications for the Self-Pollution Scenario  

E-Print Network (OSTI)

We investigate the suggestion that there are stellar populations in some globular clusters with enhanced helium (Y from 0.28 to 0.40) compared to the primordial value. We assume that a previous generation of massive Asymptotic Giant Branch (AGB) stars have polluted the cluster. Two independent sets of AGB yields are used to follow the evolution of helium and CNO using a Salpeter initial mass function (IMF) and two top-heavy IMFs. In no case are we able to produce the postulated large Y ~ 0.35 without violating the observational constraint that the CNO content is nearly constant.

Amanda Karakas; Yeshe Fenner; Alison Sills; Simon Campbell; John Lattanzio

2006-08-17T23:59:59.000Z

322

The Chemical Evolution of Helium in Globular Clusters: Implications for the Self-Pollution Scenario  

E-Print Network (OSTI)

We investigate the suggestion that there are stellar populations in some globular clusters with enhanced helium (Y from 0.28 to 0.40) compared to the primordial value. We assume that a previous generation of massive Asymptotic Giant Branch (AGB) stars have polluted the cluster. Two independent sets of AGB yields are used to follow the evolution of helium and CNO using a Salpeter initial mass function (IMF) and two top-heavy IMFs. In no case are we able to produce the postulated large Y ~ 0.35 without violating the observational constraint that the CNO content is nearly constant.

Karakas, A I; Sills, A; Campbell, S; Lattanzio, J C; Karakas, Amanda; Fenner, Yeshe; Sills, Alison; Campbell, Simon; Lattanzio, John

2006-01-01T23:59:59.000Z

323

Perspectives GmbH | Open Energy Information  

Open Energy Info (EERE)

Perspectives GmbH Jump to: navigation, search Name: Perspectives GmbH Place: Hamburg, Germany Zip: 22045 Product: Germany-based consultancy focusing on CDMJI projects as well as...

324

INFORMATION STANDARDIZATION FROM A DESIGN PERSPECTIVE  

E-Print Network (OSTI)

475 INFORMATION STANDARDIZATION FROM A DESIGN PERSPECTIVE ALEXANDER KOUTAMANIS Delft University is that it should be supported by extensive standardization of design and building information. This standardization, continuity, flexibility and adaptability. From a design perspective standardization refers to three distinct

Paris-Sud XI, Université de

325

Chemi-ionization reactions involving metastable helium atoms at high energy P. Pradel and J. J. Laucagne  

E-Print Network (OSTI)

1263 Chemi-ionization reactions involving metastable helium atoms at high energy P. Pradel and J. J dépend du défaut d'énergie de la réaction. Abstract - Total chemi-ionization cross-sections have been. Introduction. Over the last decade the chemi-ionization of atomic or molecular gases by metastable helium

Paris-Sud XI, Université de

326

Gas Exchange of Algae: II. Effects of Oxygen, Helium, and Argon on the Photosynthesis of Chlorella pyrenoidosa  

Science Journals Connector (OSTI)

...verify that nitrogen, helium...and exit gases was identical...that the solubility of the gases in the algal...dioxide in nitrogen, helium...error due to water vapor pressure...properties of the gas molecules...closely matches nitrogen (Handbook...

Elizabeth C. B. Ammann; Victoria H. Lynch

1966-07-01T23:59:59.000Z

327

High-temperature gas-cooled reactor helium compatibility studies: results of 10,000-hour exposure of selected alloys in simulated reactor helium  

SciTech Connect

Work on the HTGR Helium Compatibility Task accomplished during the period March 31, 1977 through September 30, 1979, is documented in this report. Emphasis is on the results and analyses of creep data to 10,000 h and the detailed metallurgical evaluations performed on candidate alloy specimens tested for up to 10,000 h. Long-term creep and unstressed aging data in controlled-impurity helium and in air at 800, 900, and 1000/sup 0/C are reported for alloys included in the program in FY-76, including the wrought solid-solution-strengthened alloys, Hastelloy X, Hastelloy S, RA 333, and HD 556, and the centrifugally cast austenitic alloys, HK 40, Supertherm, Manaurite 36X, Manaurite 36XS, and Manaurite 900.

Lechtenberg, T.A.; Stevenson, R.D.; Johnson, W.R.

1980-05-01T23:59:59.000Z

328

DOE Perspectives on Sustainable Bioenergy Landscapes  

Energy.gov (U.S. Department of Energy (DOE))

DOE Perspectives on Sustainable Bioenergy Landscapes; Kristen Johnson, Sustainability Program Technology Manager, Bioenergy Technologies Office; November 19, 2014

329

Biochar and Carbon Sequestration: A Regional Perspective  

E-Print Network (OSTI)

Biochar and Carbon Sequestration: A Regional Perspective A report prepared for East of England #12;Low Carbon Innovation Centre Report for EEDA Biochar and Carbon Sequestration: A Regional Perspective 20/04/2009 ii Biochar and Carbon Sequestration: A Regional Perspective A report prepared for East

Everest, Graham R

330

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

331

It's Elemental - Isotopes of the Element Magnesium  

NLE Websites -- All DOE Office Websites (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%

332

It's Elemental - Isotopes of the Element Chlorine  

NLE Websites -- All DOE Office Websites (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%

333

It's Elemental - Isotopes of the Element Potassium  

NLE Websites -- All DOE Office Websites (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%

334

It's Elemental - Isotopes of the Element Phosphorus  

NLE Websites -- All DOE Office Websites (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

335

It's Elemental - Isotopes of the Element Oxygen  

NLE Websites -- All DOE Office Websites (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%

336

It's Elemental - Isotopes of the Element Gallium  

NLE Websites -- All DOE Office Websites (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%

337

It's Elemental - Isotopes of the Element Sodium  

NLE Websites -- All DOE Office Websites (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%

338

It's Elemental - Isotopes of the Element Neon  

NLE Websites -- All DOE Office Websites (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 - -

339

It's Elemental - Isotopes of the Element Copper  

NLE Websites -- All DOE Office Websites (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%

340

It's Elemental - Isotopes of the Element Boron  

NLE Websites -- All DOE Office Websites (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%

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

It's Elemental - Isotopes of the Element Tungsten  

NLE Websites -- All DOE Office Websites (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%

342

It's Elemental - Isotopes of the Element Carbon  

NLE Websites -- All DOE Office Websites (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 - -

343

It's Elemental - Isotopes of the Element Rhenium  

NLE Websites -- All DOE Office Websites (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%

344

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

345

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

346

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

347

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

348

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...

349

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

350

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

351

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

352

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

353

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

354

Helium irradiation effects in polycrystalline Si, silica, and single crystal Si  

SciTech Connect

Transmission electron microscopy (TEM) has been used to investigate the effects of room temperature 6 keV helium ion irradiation of a thin ({approx_equal}55 nm thick) tri-layer consisting of polycrystalline Si, silica, and single-crystal Si. The ion irradiation was carried out in situ within the TEM under conditions where approximately 24% of the incident ions came to rest in the specimen. This paper reports on the comparative development of irradiation-induced defects (primarily helium bubbles) in the polycrystalline Si and single-crystal Si under ion irradiation and provides direct measurement of a radiation-induced increase in the width of the polycrystalline layer and shrinkage of the silica layer. Analysis using TEM and electron energy-loss spectroscopy has led to the hypothesis that these result from helium-bubble-induced swelling of the silicon and radiation-induced viscoelastic flow processes in the silica under the influence of stresses applied by the swollen Si layers. The silicon and silica layers are sputtered as a result of the helium ion irradiation; however, this is estimated to be a relatively minor effect with swelling and stress-related viscoelastic flow being the dominant mechanisms of dimensional change.

Abrams, K. J.; Greaves, G.; Berg, J. A. van den [Materials and Physics Research Centre, University of Salford, Salford (United Kingdom); Hinks, J. A.; Donnelly, S. E. [School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Pawley, C. J. [Materials and Physics Research Centre, University of Salford, Salford (United Kingdom); School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Eyidi, D. [Institut Pprime, Universite de Poitiers, Poitiers (France); Ward, M. B. [Institute for Materials Research, University of Leeds, Leeds (United Kingdom)

2012-04-15T23:59:59.000Z

355

Helium ion beam milling to create a nano-structured domain wall magnetoresistance spin valve  

Science Journals Connector (OSTI)

We have fabricated and measured single domain wall magnetoresistance devices with sub-20 nm gap widths using a novel combination of electron beam lithography and helium ion beam milling. The measurement wires and external profile of the spin valve are fabricated by electron beam lithography and lift-off. The critical bridge structure is created using helium ion beam milling, enabling the formation of a thinner gap (and so a narrower domain wall) than that which is possible with electron beam techniques alone. Four-point probe resistance measurements and scanning electron microscopy are used to characterize the milled structures and optimize the He ion dose. Successful operation of the device as a spin valve is demonstrated, with a 0.2% resistance change as the external magnetic field is cycled. The helium ion beam milling efficiency as extracted from electrical resistance measurements is 0.044 atoms/ion, about half the theoretical value. The gap in the device is limited to a maximum of 20 nm with this technique due to sub-surface swelling caused by injected ions which can induce catastrophic failure in the device. The fine patterning capabilities of the helium ion microscope milling technique indicate that sub-5 nm constriction widths could be possible.

Yudong Wang; S A Boden; D M Bagnall; H N Rutt; C H de Groot

2012-01-01T23:59:59.000Z

356

Heat capacity of adsorbed Helium-3 at ultra-low temperatures  

E-Print Network (OSTI)

Heat capacity of adsorbed Helium-3 at ultra-low temperatures J. Elbs, C. Winkelmann, Yu. M. Bunkov of monolayers of 3He adsorbed on the surface of a cell filled with superfluid 3He. We found that at ultra low. The replacement of adsorbed 3He by 4He changes the heat capacity of the sample by an order of magnitude

Boyer, Edmond

357

Helium corona-assisted air discharge Nan Jiang, Lei Gao, Ailing Ji, and Zexian Caoa)  

E-Print Network (OSTI)

of non-thermal plasmas. By taking advantage of the low onset voltage for helium corona, air discharge of vacuum. In order to reduce the expense associated with vacuum systems, many atmospheric non- thermal profit the application of non-thermal plasmas. Inspired by our own research on gas discharges, espe

Zexian, Cao

358

Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model  

E-Print Network (OSTI)

Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model Geoffroy J isotherms of 4He in a silica aerogel be- come discontinuous below a critical temperature. We show by the aerogel structure, but to the disorder-driven critical point predicted for the athermal out

Boyer, Edmond

359

Possible observation of the roughening transition in helium S. Balibar and B. Castaing  

E-Print Network (OSTI)

L-329 Possible observation of the roughening transition in helium S. Balibar and B. Castaing Groupe. Abstract. 2014 We suggest that the surface of hcp 4He crystals undergoes a roughening transition at 1 K of the roughening transition was first introduced by Burton, Cabrera and Franck [1] in order to explain different

Paris-Sud XI, Université de

360

Critical Casimir Effect and Wetting by Helium Mixtures T. Ueno,* S. Balibar, T. Mizusaki,  

E-Print Network (OSTI)

He-4He mixtures against a sapphire window. We have found that this angle is finite and does not tend [1­4]. We found an exception to it by studying helium mixtures in contact with a sapphire window [5 of the fluctuations of superfluidity, i.e., a critical Casimir effect [7­11] in the 4 He-rich film between

Caupin, Frédéric

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

Crystallization and melting of a system of charges in a liquid helium cluster  

SciTech Connect

A system of like (positive or negative) charges forming 'snowballs' or 'bubbles' in a three-dimensional liquid helium cluster is investigated. The charges are confined inside the cluster by an 'image potential' produced by the polarization of liquid helium. The stability of a multiply charged helium cluster is considered. Computer simulations are used to investigate the crystallization and melting of the system of charges depending on the dimensionless parameter T* = k{sub B}T{epsilon}R/e{sup 2}, where k{sub B} is the Boltzmann constant, T is the temperature, {epsilon} is the dielectric constant of liquid helium, R is the cluster radius, and e is a unit charge. Various characteristics, including symmetry groups and moments, have been found for equilibrium configurations of charges in a cluster with N = 1-100 charges. At small N {approx} 10, Thomson's model of successive filling of 'belts' of charges can be used to describe the structure of equilibrium configurations of charges. At large N, the description of the structure formed by charges using the idea of a quasi-two-dimensional 'closed triangular lattice' with topological defects is more adequate. Formally, this description is valid starting from N = 4. The melting of a 'lattice' of charges is described. A number of our conclusions can be generalized to clusters of other noble gases.

Livshits, A. M., E-mail: livshits@isan.troitsk.ru; Lozovik, Yu. E. [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation)

2007-10-15T23:59:59.000Z

362

D0 Silicon Upgrade: Gas Helium Storage Tank Pressure Vessel Engineering Note  

SciTech Connect

This is to certify that Beaird Industries, Inc. has done a white metal blast per SSPC-SP5 as required per specifications on the vessel internal. Following the blast, a black light inspection was performed by Beaird Quality Control personnel to assure that all debris, grease, etc. was removed and interior was clean prior to closing vessel for helium test.

Rucinski, Russ; /Fermilab

1996-11-11T23:59:59.000Z

363

A liquid-helium cooled large-area silicon PIN photodiode x-ray detector  

E-Print Network (OSTI)

An x-ray detector using a liquid-helium cooled large-area silicon PIN photodiode has been developed along with a tailor-made charge sensitive preamplifier whose first-stage JFET has been cooled. The operating temperature of the JFET has been varied separately and optimized. The x- and $\\gamma$-ray energy spectra for an \

Yoshizumi Inoue; Shigetaka Moriyama; Hideyuki Hara; Makoto Minowa; Fumio Shimokoshi

1995-04-27T23:59:59.000Z

364

Feasibility of measuring surface electron spin dynamics by inelastic scattering of metastable helium atoms  

E-Print Network (OSTI)

helium atoms M. El-Batanouny, G. Murthy, and C. R. Willis Department of Physics, Boston University atoms (He*) from surfaces of magnetic insulators to study the dynamical properties of surface electron a metastable He atom and the surface electron spins are determined by a configuration interaction calculation

Kais, Sabre

365

Neutron scattering study of the excitation spectrum of solid helium at ultra-low temperatures  

Science Journals Connector (OSTI)

There has been a resurgence of interest in the properties of solid helium due to the recent discovery of non-classical rotational inertia (NCRI) in solid 4He by Chan and coworkers below 200 mK which they have int...

Elizabeth Blackburn; John Goodkind; Sunil K. Sinha; Collin Broholm; John Copley…

2008-10-01T23:59:59.000Z

366

Creep and rupture behavior of a special grade Hastelloy-X in simulated HTGR helium  

SciTech Connect

Creep and rupture tests were conducted for Hastelloy-XR (a modified version of the conventional Hastelloy alloy X) at 800, 900, and 1000/sup 0/C in simulated high-temperature gas-cooled reactor helium. Creep testing machines with special control of helium chemistry were used. As a result, the scatter of creep-rupture data could be reduced, and the variability of creep-rupture behavior due to manufacturing history could be resolved. Results of metallography and carbon analysis of ruptured specimens showed that the material improved resistance to corrosion in the helium environment, and carbon intrusion during the steady-state creep stage was suppressed to a negligible level. Under refined test conditions combined with the quality controlled material, it was demonstrated that there was little significant difference between helium and air in the creep-rupture results obtained at 800 to 1000/sup 0/C up to about 10/sup 4/h. The importance of maintaining the protective function of the surface oxide film of alloys was stressed in securing reproducibility and predictability of long-time creep performance.

Kurata, Y.; Kondo, T.; Ogawa, Y.

1984-08-01T23:59:59.000Z

367

Gas-Surface Energy Exchange in Collisions of Helium Atoms with Aligned Single-Walled Carbon  

E-Print Network (OSTI)

1 Gas-Surface Energy Exchange in Collisions of Helium Atoms with Aligned Single-Walled Carbon #12;2 ABSTRACT Since gas flows in micro/nano devices are dominated by the interaction of gas molecules accommodation of gas molecules on surfaces. The scattering of gas molecules on quartz surfaces covered with VA

Maruyama, Shigeo

368

Helium, Iron and Electron Particle Transport and Energy Transport Studies on the TFTR Tokamak  

DOE R&D Accomplishments (OSTI)

Results from helium, iron, and electron transport on TFTR in L-mode and Supershot deuterium plasmas with the same toroidal field, plasma current, and neutral beam heating power are presented. They are compared to results from thermal transport analysis based on power balance. Particle diffusivities and thermal conductivities are radially hollow and larger than neoclassical values, except possibly near the magnetic axis. The ion channel dominates over the electron channel in both particle and thermal diffusion. A peaked helium profile, supported by inward convection that is stronger than predicted by neoclassical theory, is measured in the Supershot The helium profile shape is consistent with predictions from quasilinear electrostatic drift-wave theory. While the perturbative particle diffusion coefficients of all three species are similar in the Supershot, differences are found in the L-Mode. Quasilinear theory calculations of the ratios of impurity diffusivities are in good accord with measurements. Theory estimates indicate that the ion heat flux should be larger than the electron heat flux, consistent with power balance analysis. However, theoretical values of the ratio of the ion to electron heat flux can be more than a factor of three larger than experimental values. A correlation between helium diffusion and ion thermal transport is observed and has favorable implications for sustained ignition of a tokamak fusion reactor.

Synakowski, E. J.; Efthimion, P. C.; Rewoldt, G.; Stratton, B. C.; Tang, W. M.; Grek, B.; Hill, K. W.; Hulse, R. A.; Johnson, D .W.; Mansfield, D. K.; McCune, D.; Mikkelsen, D. R.; Park, H. K.; Ramsey, A. T.; Redi, M. H.; Scott, S. D.; Taylor, G.; Timberlake, J.; Zarnstorff, M. C. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Kissick, M. W. (Wisconsin Univ., Madison, WI (United States))

1993-03-00T23:59:59.000Z

369

Fusion Engineering and Design 82 (2007) 22172225 Integrated thermo-fluid analysis towards helium flow  

E-Print Network (OSTI)

Fusion Engineering and Design 82 (2007) 2217­2225 Integrated thermo-fluid analysis towards helium. Andob, I. Komadab a Fusion Engineering Sciences, Mechanical and Aerospace Eng. Department, University the ITER test blanket module (TBM) warrants the need of extensive computer aided engineering (CAE

Abdou, Mohamed

370

Helium enhancements in globular cluster stars from Asymptotic Giant Branch star pollution  

E-Print Network (OSTI)

Using a chemical evolution model we investigate the intriguing suggestion that there are populations of stars in some globular clusters (e.g. NGC 2808, omega Centauri) with enhanced levels of helium (Y from about 0.28 to 0.40) compared to the majority of the population that presumably have a primordial helium abundance. We assume that a previous generation of massive low-metallicity Asymptotic Giant Branch (AGB) stars has polluted the cluster gas via a slow stellar wind. We use two independent sets of AGB yields computed from detailed models to follow the evolution of helium, carbon, nitrogen and oxygen in the cluster gas using a Salpeter initial mass function (IMF) and a number of top-heavy IMFs. In no case were we able to fit the observational constraints, Y > 0.30 and C+N+O approximately constant. Depending on the shape of the IMF and the yields, we either obtained Y approximately greater than 0.30 and large increases in C+N+O or Y < 0.30 and C+N+O approximately constant. These results suggest that either AGB stars alone are not responsible for the large helium enrichment or that any dredge-up from this generation of stars was less than predicted by standard models.

Amanda Karakas; Yeshe Fenner; Alison Sills; Simon Campbell; John Lattanzio

2006-05-21T23:59:59.000Z

371

Perspectives Computational Biology in Brazil  

E-Print Network (OSTI)

Perspectives Computational Biology in Brazil Goran Neshich Introduction At the request of the PLoS Computational Biology Editor-in- Chief, I agreed to write about computational biology in Brazil (see author of the field itself is short); b) the current state of the field in Brazil; c) the influence of computational

Neshich, Goran

372

Theoretical Perspectives on Protein Folding  

E-Print Network (OSTI)

Theoretical Perspectives on Protein Folding D. Thirumalai,1 Edward P. O'Brien,2 Greg Morrison,3 Understanding how monomeric proteins fold under in vitro conditions is crucial to describing their functions remains to be done to solve the protein folding problem in the broadest sense. 159 Annu.Rev.Biophys.2010

Thirumalai, Devarajan

373

Biomedical Ontologies: a functional perspective  

E-Print Network (OSTI)

Biomedical Ontologies: a functional perspective Daniel L. Rubin, Nigam H. Shah and Natalya F. Noy in biology makes it difficult for researchers to stay abreast of current biomedical knowl- edge and to make, their attributes and relationships among the entities in a domain of discourseçare increasingly enabling biomedical

Rubin, Daniel L.

374

E-Print Network 3.0 - abundance isotopic Sample Search Results  

NLE Websites -- All DOE Office Websites (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...

375

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

NLE Websites -- All DOE Office Websites (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...

376

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.

377

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...

378

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

379

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

NLE Websites -- All DOE Office Websites (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...

380

Final Report, NEAC Subcommittee for Isotope Research & Production Planning  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

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

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

382

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

SciTech Connect

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

383

Measurements of the volt-ampere characteristics and the breakdown voltages of direct-current helium and hydrogen discharges in microgaps  

SciTech Connect

The discharge phenomena for micro meter gap sizes include many interesting problems from engineering and physical perspectives. In this paper, the authors deal with the experimental and theoretical results of the breakdown voltage and current-voltage characteristics of the direct-current helium and hydrogen discharges. The measurements were performed at a constant pressure of around one atmosphere, while varying the gap size between two parallel plane tungsten electrodes between 1??m and 100??m. From the measured breakdown voltage curves, the effective yields and the ionization coefficients were derived for both gases. Present data for the ionization coefficients correlate with the data obtained for the breakdown voltage curves measured for fixed 100??m interelectrode separation. The current-voltage characteristics were plotted for the various gap sizes illustrating the role of the field emission effects in the microgaps. Based on the Fowler-Nordheim theory, the enhancement factors were determined. The gap spacing dependence of the field emission current can be explained by the introduction of two ideas, the first being a space charge effect by emitted electrons, and the second a change in the breakdown mechanism. Experimental results, presented here, demonstrate that Townsend phenomenology breaks down when field emission becomes the key mechanism affecting the breakdown and deforming the left hand side of the breakdown voltage curves.

Klas, M.; Matej?ik, Š. [Department of Experimental Physics, Comenius University, Mlynskadolina F2, 84248 Bratislava (Slovakia); Radjenovi?, B.; Radmilovi?-Radjenovi?, M. [Institute of Physics, University of Belgrade, P.O. Box 57, 11080 Belgrade (Serbia)

2014-10-15T23:59:59.000Z

384

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

385

Investigation of Countercurrent Helium-Air Flows in Air-ingress Accidents for VHTRs  

SciTech Connect

The primary objective of this research is to develop an extensive experimental database for the air- ingress phenomenon for the validation of computational fluid dynamics (CFD) analyses. This research is intended to be a separate-effects experimental study. However, the project team will perform a careful scaling analysis prior to designing a scaled-down test facility in order to closely tie this research with the real application. As a reference design in this study, the team will use the 600 MWth gas turbine modular helium reactor (GT-MHR) developed by General Atomic. In the test matrix of the experiments, researchers will vary the temperature and pressure of the helium— along with break size, location, shape, and orientation—to simulate deferent scenarios and to identify potential mitigation strategies. Under support of the Department of Energy, a high-temperature helium test facility has been designed and is currently being constructed at Ohio State University, primarily for high- temperature compact heat exchanger testing for the VHTR program. Once the facility is in operation (expected April 2009), this study will utilize high-temperature helium up to 900°C and 3 MPa for loss-of-coolant accident (LOCA) depressurization and air-ingress experiments. The project team will first conduct a scaling study and then design an air-ingress test facility. The major parameter to be measured in the experiments is oxygen (or nitrogen) concentration history at various locations following a LOCA scenario. The team will use two measurement techniques: 1) oxygen (or similar type) sensors employed in the flow field, which will introduce some undesirable intrusiveness, disturbing the flow, and 2) a planar laser-induced fluorescence (PLIF) imaging technique, which has no physical intrusiveness to the flow but requires a transparent window or test section that the laser beam can penetrate. The team will construct two test facilities, one for high-temperature helium tests with local sensors and the other for low- temperature helium tests with the PLIF technique. The results from the two instruments will provide a means to cross-calibrate the measurement techniques.

Sun, Xiaodong; Christensen, Richard; Oh, Chang

2013-10-03T23:59:59.000Z

386

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

387

REPORT OF SURVEY OF OAK RIDGE ISOTOPE  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

388

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

389

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

390

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

391

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

392

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

393

Heat Transfer from an Oxidized Large Copper Surface to Liquid Helium: Dependence on Surface Orientation and Treatment  

Science Journals Connector (OSTI)

Heat transfer of large copper plates (18 × 76 mm) in liquid helium has been measured as a function of orientation and treatment of the heat transfer surface. The results relate to applications of large ... clarif...

A. Iwamoto; T. Mito; K. Takahata; N. Yanagi…

1996-01-01T23:59:59.000Z

394

Excitation frequency effects on atmospheric-pressure helium RF microplasmas: plasma density, electron energy and plasma impedance  

Science Journals Connector (OSTI)

...The effects of the driving RF frequency on the properties of low temperature atmospheric pressure helium microplasmas are discussed in light...?...m microdischarge driven at constant input power with a 10 MHz–...

K. McKay; F. Iza; M. G. Kong

2010-12-01T23:59:59.000Z

395

Application of a Microwave-Induced Helium Plasma Detector at Atmospheric Pressure for Gas Chromatographic Capillary Columns  

Science Journals Connector (OSTI)

......microwave-induced plasma emission detector...microwave- induced plasma that operates at atmospheric pressure using helium...to within 1 cm of the plasma discharge. The quartz...Raytheon PGM-10X2 2450 MHz microwave power supply......

Stanley P. Wasik; Frederick P. Schwarz

1980-12-01T23:59:59.000Z

396

Muon transfer induced by collisional excitation of helium muonide He?+ after muon catalyzed fusionafter muon catalyzed fusion  

Science Journals Connector (OSTI)

Possibility of negative muon transfer from helium muonide He?+...to T /or D/ through collisional excitation after muon catalyzed fusion has been pointed out. The...+...in the medium of tritium or deuterium. It is...

K. Yoshihara; T. Sekine

1988-09-01T23:59:59.000Z

397

Radiation Resistance of Structural Materials of Nuclear Reactors on Irradiation with High-Energy Hydrogen and Helium Ions  

Science Journals Connector (OSTI)

Basic principles of determination of the radiation resistance of structural materials of nuclear reactors with implantation of high-energy hydrogen and helium atoms have been presented. ... them with hydrogen and...

F. F. Komarov; A. F. Komarov; Vl. V. Pil?ko…

2013-11-01T23:59:59.000Z

398

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

Science Journals Connector (OSTI)

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

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

399

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...

400

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

NLE Websites -- All DOE Office Websites (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...

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

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

402

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

403

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

404

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

405

Exergy Analysis of the Cryogenic Helium Distribution System for the Large Hadron Collider (LHC)  

E-Print Network (OSTI)

The Large Hadron Collider (LHC) at CERN features the world’s largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility..

Claudet, S; Tavian, L; Wagner, U; 10.1063/1.3422294

2010-01-01T23:59:59.000Z

406

Helium circulator design considerations for modular high temperature gas-cooled reactor plant  

SciTech Connect

Efforts are in progress to develop a standard modular high temperature gas-cooled reactor (MHTGR) plant that is amenable to design certification and serial production. The MHTGR reference design, based on a steam cycle power conversion system, utilizes a 350 MW(t) annular reactor core with prismatic fuel elements. Flexibility in power rating is afforded by utilizing a multiplicity of the standard module. The circulator, which is an electric motor-driven helium compressor, is a key component in the primary system of the nuclear plant, since it facilitates thermal energy transfer from the reactor core to the steam generator; and, hence, to the external turbo-generator set. This paper highlights the helium circulator design considerations for the reference MHTGR plant and includes a discussion on the major features of the turbomachine concept, operational characteristics, and the technology base that exists in the U.S.

McDonald, C.F.; Nichols, M.K.

1987-01-01T23:59:59.000Z

407

Helium circulator design considerations for modular high temperature gas-cooled reactor plant  

SciTech Connect

Efforts are in progress to develop a standard modular high temperature gas-cooled reactor (MHTGR) plant that is amenable to design certification and serial production. The MHTGR reference design, based on a steam cycle power conversion system, utilizes a 350 MW(t) annular reactor core with prismatic fuel elements. Flexibility in power rating is afforded by utilizing a multiplicity of the standard module. The circulator, which is an electric motor-driven helium compressor, is a key component in the primary system of the nuclear plant, since it facilitates thermal energy transfer from the reactor core to the steam generator; and, hence, to the external turbo-generator set. This paper highlights the helium circulator design considerations for the reference MHTGR plant and includes a discussion on the major features of the turbomachine concept, operational characteristics, and the technology base that exists in the US.

McDonald, C.F.; Nichols, M.K.

1986-12-01T23:59:59.000Z

408

OGLE-2013-SN-079: a lonely supernova consistent with a helium shell detonation  

E-Print Network (OSTI)

We present observational data for a peculiar supernova discovered by the OGLE-IV survey and followed by the Public ESO Spectroscopic Survey for Transient Objects. The inferred redshift of z=0.07 implies an absolute magnitude in the rest-frame I-band of M$_{I}\\sim-17.6$ mag. This places it in the luminosity range between normal Type Ia SNe and novae. Optical and near infrared spectroscopy reveal mostly Ti and Ca lines, and an unusually red color arising from strong depression of flux at rest wavelengths detonation of a helium shell around a low-mass CO white dwarf and "double-detonation" models that include a secondary detonation of a CO core following a primary detonation in an overlying helium shell.

Inserra, C; Wyrzykowski, L; Smartt, S J; Fraser, M; Nicholl, M; Shen, K J; Jerkstrand, A; Gal-Yam, A; Howell, D A; Maguire, K; Mazzali, P; Valenti, S; Taubenberger, S; Benitez-Herrera, S; Bersier, D; Blagorodnova, N; Campbell, H; Chen, T -W; Elias-Rosa, N; Hillebrandt, W; Kostrzewa-Rutkowska, Z; Kozlowski, S; Kromer, M; Lyman, J D; Polshaw, J; Ropke, F K; Ruiter, A J; Smith, K; Spiro, S; Sullivan, M; Yaron, O; Young, D; Yuan, F

2014-01-01T23:59:59.000Z

409

Frequency-dependent polarizability of helium including relativistic effects with nuclear recoil terms  

E-Print Network (OSTI)

Future metrology standards will be partly based on physical quantities computed from first principles rather than measured. In particular, a new pressure standard can be established if the dynamic polarizability of helium can be determined from theory with an uncertainty smaller than 0.2 ppm. We present calculations of the frequency-dependent part of this quantity including relativistic effects with full account of leading nuclear recoil terms and using highly optimized explicitly correlated basis sets. A particular emphasis is put on uncertainty estimates. At the He-Ne laser wavelength of 632.9908 nm, the computed polarizability value of 1.391 811 41 a.u. has uncertainty of 0.1 ppm that is two orders of magnitude smaller than those of the most accurate polarizability measurements. We also obtained an accurate expansion of the helium refractive index in powers of density.

Piszczatowski, Konrad; Komasa, Jacek; Jeziorski, Bogumil; Szalewicz, Krzysztof

2015-01-01T23:59:59.000Z

410

EXERGY ANALYSIS OF THE CRYOGENIC HELIUM DISTRIBUTION SYSTEM FOR THE LARGE HADRON COLLIDER (LHC)  

SciTech Connect

The Large Hadron Collider (LHC) at CERN features the world's largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility.

Claudet, S.; Lebrun, Ph.; Tavian, L.; Wagner, U. [CERN, CH-1211, Geneva, 23 (Switzerland)

2010-04-09T23:59:59.000Z

411

Superfluid helium testing of a stainless steel to titanium piping transition joint  

SciTech Connect

Stainless steel-to-titanium bimetallic transitions have been fabricated with an explosively bonded joint. This novel joining technique was conducted by the Russian Federal Nuclear Center, working under contract for the Joint Institute for Nuclear Research. These bimetallic transitions are being considered for use in future superconducting radio-frequency cavity cryomodule assemblies. This application requires cryogenic testing to demonstrate that this transition joint remains leak-tight when sealing superfluid helium. To simulate a titanium cavity vessel connection to a stainless steel service pipe, bimetallic transition joints were paired together to fabricate piping assemblies. These piping assemblies were then tested in superfluid helium conditions at Fermi National Accelerator Laboratory test facilities. The transition joint test program will be described. Fabrication experience and test results will be presented.

Soyars, W.; /Fermilab; Basti, A.; Bedeschi, F.; /INFN, Pisa; Budagov, J.; /Dubna, JINR; Foley, M.; Harms, E.; Klebaner, A.; Nagaitsev, S.; /Fermilab; Sabirov, B.; Dubna, JINR

2009-11-01T23:59:59.000Z

412

A Continuous 4He Refrigerator for Use in a Superfluid Helium Bath  

SciTech Connect

In cryogenic applications in space, the base temperature, Tmin of the helium bath in the dewar is typically determined by the design of the porous plug and the associated plumbing. For certain experiments, the required operating temperature of the instrument is lower than the bath temperature. In the laboratory, temperatures below 1.2 K require very large pumps or the use of 3He systems. We have demonstrated a modified 4He refrigerator with a continuous fill from a superfluid helium bath with a base temperature more than 0.5 K below the bath temperature. We describe the operation as well as the mechanism of such a refrigerator. For operation in space the refrigerator would need to be equipped with a porous plug to retain the fluid.

Wang, Suwen; Avaloff, D.; Nissen, J. A.; Stricker, D. A.; Lipa, J. A. [Hansen Experimental Physics Laboratory, Stanford University, Stanford, California (United States)

2006-09-07T23:59:59.000Z

413

Simultaneous measurements of super-radiance at multiple wavelengths from helium excited states: (I) Experiment  

E-Print Network (OSTI)

In this paper, we report the results of measurements of the intensities and delays of super-radiance decays from excited helium atoms at multiple wavelengths. The experiment was performed using extreme ultraviolet radiation produced by the free electron laser at the SPring-8 Compact SASE Source test accelerator facility as an excitation source. We observed super-radiant transitions on the $1s3p \\to 1s2s$ ($\\lambda=$502 nm), $1s3d \\to 1s2p$ ($\\lambda=$668 nm), and $1s3s \\to 1s2p$ ($\\lambda=$728 nm) transitions. The pulse energy of each transition and its delay time were measured as a function of the target helium gas density. Several interesting features of the data, some of which appear to contradict with the predictions of the simple two-level super-radiance theory, are pointed out.

Nakajima, Kyo; Iwayama, Hiroshi; Kuma, Susumu; Miyamoto, Yuki; Nagasono, Mitsuru; Ohae, Chiaki; Togashi, Tadashi; Yabashi, Makina; Shigemasa, Eiji; Sasao, Noboru

2014-01-01T23:59:59.000Z

414

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

415

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

416

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...

417

A Colorado Perspective: The New Energy Economy  

E-Print Network (OSTI)

transmission, have languished. Colorado looks forward withA Colorado Perspective: The New Energy Economy Jim Martin*REPORTING .. VIII. COLORADO'S STATE

Martin, Jim; Brannon, Ginny

2009-01-01T23:59:59.000Z

418

Medical students' perspectives on clinical empathy training.  

E-Print Network (OSTI)

on Clinical Empathy Training B Afghani 1 , S Besimanto 2 , Aon Clinical Empathy Training Education for Health, Volumethe barriers to empathy training from the perspective of

Afghani, Behnoosh; Besimanto, Shabnam; Amin, Alpesh; Shapiro, Johanna

2011-01-01T23:59:59.000Z

419

Line Management Perspective: National Nuclear Security Administration...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Perspective: National Nuclear Security Administration (NNSA) Addthis Description Slide Presentation by Jim McConnell, Acting Associate Administrator for Infrastructure and...

420

Utility Partnership Webinar Series: Industrial Customer Perspectives...  

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

Email: jredick@bcs-hq.com Presentations: http:www1.eere.energy.govindustryutilities A premier aerospace and defense company 3 An Industrial Customer Perspective on...

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

FIRST_Research Perspective_Overbury_PCET  

NLE Websites -- All DOE Office Websites (Extended Search)

the system PQ adsorbed on OLC FIRST Center Research Perspective: PCET Reactions and SorptionDynamics of Quinones on Carbon Surfaces with Pseudocapacitive Energy Storage...

422

Oil market in international and Norwegian perspectives.  

E-Print Network (OSTI)

??Crude oil is the most important energy source in global perspective. About 35 percent of the world’s primary energy consumption is supplied by oil, followed… (more)

Singsaas, Julia Nazyrova

2009-01-01T23:59:59.000Z

423

Interacting double dark resonances in a hot atomic vapor of helium  

SciTech Connect

We experimentally and theoretically study two different tripod configurations using metastable helium ({sup 4}He*), with the probe field polarization perpendicular and parallel to the quantization axis, defined by an applied weak magnetic field. In the first case, the two dark resonances interact incoherently and merge together into a single electromagnetically induced transparency peak with increasing coupling power. In the second case, we observe destructive interference between the two dark resonances inducing an extra absorption peak at the line center.

Kumar, S.; Ghosh, R. [School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Laupretre, T.; Bretenaker, F.; Goldfarb, F. [Laboratoire Aime Cotton, CNRS-Universite Paris Sud 11, F-91405 Orsay Cedex (France)

2011-08-15T23:59:59.000Z

424

Modeling and Simulation Optimization and Feasibility Studies for the Neutron Detection without Helium-3 Project  

SciTech Connect

This report details the results of the modeling and simulation work accomplished for the ‘Neutron Detection without Helium-3’ project during the 2011 and 2012 fiscal years. The primary focus of the project is to investigate commercially available technologies that might be used in safeguards applications in the relatively near term. Other technologies that are being developed may be more applicable in the future, but are outside the scope of this study.

Ely, James H.; Siciliano, Edward R.; Swinhoe, Martyn T.; Lintereur, Azaree T.

2013-01-01T23:59:59.000Z

425

Final Technical Report for the Neutron Detection without Helium-3 Project  

SciTech Connect

This report details the results of the research and development work accomplished for the ‘Neutron Detection without Helium-3’ project conducted during the 2011-2013 fiscal years. The primary focus of the project was to investigate commercially available technologies that might be used in safeguards applications in the relatively near term. Other technologies that are being developed may be more applicable in the future, but were outside the scope of this study.

Ely, James H.; Bliss, Mary; Kouzes, Richard T.; Lintereur, Azaree T.; Robinson, Sean M.; Siciliano, Edward R.; Swinhoe, Martyn T.; Woodring, Mitchell L.

2013-11-01T23:59:59.000Z

426

The role of correlation in the ground state energy of confined helium atom  

SciTech Connect

We analyze the ground state energy of helium atom confined by spherical impenetrable walls, and the role of the correlation energy in the total energy. The confinement of an atom in a cavity is one way in which we can model the effect of the external pressure on an atom. The calculations of energy of the system are carried out by the variational method. We find that the correlation energy remains almost constant for a range values of size of the boxes analyzed.

Aquino, N. [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Apartado Postal 55-534, 09340 México Distrito Federal (Mexico)

2014-01-14T23:59:59.000Z

427

Final Report on Isotope Ratio Techniques for Light Water Reactors  

SciTech Connect

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

428

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

429

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

430

Discovery of rubidium, strontium, molybdenum, and rhodium isotopes  

SciTech Connect

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

431

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

432

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

433

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

434

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

435

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

436

THE EXPANDING BIPOLAR SHELL OF THE HELIUM NOVA V445 PUPPIS  

SciTech Connect

From multi-epoch adaptive optics imaging and integral field unit spectroscopy, we report the discovery of an expanding and narrowly confined bipolar shell surrounding the helium nova V445 Puppis (Nova Puppis 2000). An equatorial dust disc obscures the nova remnant, and the outflow is characterized by a large polar outflow velocity of 6720 +- 650 km s{sup -1} and knots moving at even larger velocities of 8450 +- 570 km s{sup -1}. We derive an expansion parallax distance of 8.2 +- 0.5 kpc and deduce a pre-outburst luminosity of the underlying binary of log L/L{sub sun} = 4.34 +- 0.36. The derived luminosity suggests that V445 Puppis probably contains a massive white dwarf accreting at high rate from a helium star companion making it part of a population of binary stars that potentially lead to supernova Ia explosions due to accumulation of helium-rich material on the surface of a massive white dwarf.

Woudt, P. A.; Warner, B. [Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Steeghs, D.; Marsh, T. R. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Karovska, M.; Roelofs, G. H. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138-1516 (United States); Groot, P. J.; Nelemans, G. [Department of Astrophysics, Radboud University Nijmegen, P.O. Box 9010, 6500 GL, Nijmegen (Netherlands); Nagayama, T. [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Smits, D. P. [Department of Mathematical Sciences, University of South Africa, UNISA, Pretoria 0003 (South Africa); O'Brien, T., E-mail: Patrick.Woudt@uct.ac.z [University of Manchester, Jodrell Bank Observatory, Macclesfield, Cheshire SK11 9DL (United Kingdom)

2009-11-20T23:59:59.000Z

437

SPECTRA OF COSMIC-RAY PROTONS AND HELIUM PRODUCED IN SUPERNOVA REMNANTS  

SciTech Connect

Data obtained in the Advanced Thin Ionization Calorimeter (ATIC-2), Cosmic Ray Energetics and Mass (CREAM), and Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) experiments suggest that the elemental interstellar spectra of cosmic rays below the knee at a few times 10{sup 6} GeV are not simple power laws, but that they experience hardening at a magnetic rigidity of about 240 GV. Another essential feature is the difference between proton and helium energy spectra, such that the He/p ratio increases by more than 50% in the energy range from 10{sup 2} to 10{sup 4} GV. We consider the concavity of the particle spectrum resulting from the nonlinear nature of diffusive shock acceleration in supernova remnants (SNRs) as a possible reason for the observed spectrum hardening. The increase of the helium-to-proton ratio with energy can be interpreted as a consequence of cosmic-ray acceleration by forward and reverse shocks in SNRs. The contribution of particles accelerated by reverse shocks makes the concavity of the produced overall cosmic-ray spectrum more pronounced. The spectra of protons and helium nuclei accelerated in SNRs and released into the interstellar medium are calculated. The derived steady-state interstellar spectra are in reasonably good agreement with observations.

Ptuskin, Vladimir; Zirakashvili, Vladimir [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Science (IZMIRAN), Troitsk, Moscow Region 142190 (Russian Federation)] [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Science (IZMIRAN), Troitsk, Moscow Region 142190 (Russian Federation); Seo, Eun-Suk [Department of Physics and Institute of Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)] [Department of Physics and Institute of Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)

2013-01-20T23:59:59.000Z

438

FLOATING PRESSURE CONVERSION AND EQUIPMENT UPGRADES OF TWO 3.5KW, 20K, HELIUM REFRIGERATORS  

SciTech Connect

Two helium refrigerators, each rated for 3.5 KW at 20 K, are used at NASA's Johnson Space Center (JSC) in Building No. 32 to provide cryogenic-pumping within two large thermal-vacuum chambers. These refrigerators were originally commissioned in 1996. New changes to the controls of these refrigerators were recently completed. This paper describes some of the control issues that necessitated the controls change-over. It will describe the modifications and the new process control which allows the refrigerators to take advantage of the Ganni Cycle “floating pressure” control technology. The controls philosophy change-over to the floating pressure control technology was the first application on a helium gas refrigeration system. Previous implementations of the floating pressure technology have been on 4 K liquefaction and refrigeration systems, which have stored liquid helium volumes that have level indications used for varying the pressure levels (charge) in the system for capacity modulation. The upgrades have greatly improved the performance, stability, and efficiency of these two refrigerators. The upgrades have also given the operators more information and details about the operational status of the main components (compressors, expanders etc.) of the refrigerators at all operating conditions (i.e. at various loads in the vacuum chambers). The performance data of the two systems, pre and post upgrading are presented.

J. Homan, V. Ganni, A. Sidi-Yekhlef, J. Creel, R. Norton, R. Linza, G. Vargas, J. Lauterbach, J. Urbin, D. Howe

2010-04-01T23:59:59.000Z

439

Helium enrichment and Carbon-star Production in Metal-rich Populations  

E-Print Network (OSTI)

We present new theoretical stellar evolutionary models of metal-rich asymptotic giant branch (AGB) stars. Stellar models are evolved with initial masses between 1Msun and 7Msun at Z=0.007, and 1Msun and 8Msun at Z=0.014 (solar) and at Z=0.03. We evolve models with a canonical helium abundance and with helium enriched compositions (Y=0.30, 0.35, 0.40) at Z=0.014 and Z=0.03. The efficiency of third dredge-up and the mass range of carbon stars decreases with an increase in metallicity. We predict carbon stars form from initial masses between 1.75-7Msun at Z=0.007 and between 2-4.5Msun at solar metallicity. At Z=0.03 the mass range for C-star production is narrowed to 3.25-4Msun. The third dredge-up is reduced when the helium content of the model increases owing to the reduced number of thermal pulses on the AGB. A small increase of Delta Y = 0.05 is enough to prevent the formation of C stars at Z=0.03, depending on the mass-loss rate, whereas at Z=0.014, an increase of Delta Y = 0.1 is required to prevent the fo...

Karakas, Amanda I

2014-01-01T23:59:59.000Z

440

THE ON-SITE STATUS OF THE KSTAR HELIUM REFRIGERATION SYSTEM  

Science Journals Connector (OSTI)

Since the first design of the KSTAR helium refrigeration system (HRS) in year 2000 many modifications and changes have been applied due to both system optimization and improved knowledge of the KSTAR cold components. The present specification of the HRS had been fixed on March 2005. Consequent manufacturing of main equipment such as “Compressor Station” (C/S) “Cold Box” (C/B) and “Distribution Box ?1” (D/B ?1) was completed by or under the supervision of Air Liquide DTA by the end of year 2006. The major components of the C/S are 2 low and 2 high pressure compressor units and an oil-removal system. The cooling power of the C/B at 4.5 K equivalent is 9 kW achieved by using 6 turbo-expanders. The D/B ?1 is a cryostat housing 49 cryogenic valves 2 supercritical helium circulators 1 cold compressor and 7 heat exchangers immersed in a 6? m 3 liquid helium storage.

H.-S. Chang; D. S. Park; J. J. Joo; K. M. Moon; K. W. Cho; Y. S. Kim; J. S. Bak; H. M. Kim; M. C. Cho; I. K. Kwon; E. Fauve; J.-M. Bernhardt; P. Dauguet; J. Beauvisage; F. Andrieu; S.-H. Yang; G. M. Gistau Baguer

2008-01-01T23:59:59.000Z

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

Supernovae from direct collisions of white dwarfs and the role of helium shell ignition  

E-Print Network (OSTI)

Models for supernovae (SNe) arising from thermonuclear explosions of white dwarfs (WDs) have been extensively studied over the last few decades, mostly focusing on the single degenerate (accretion of material of a WD) and double degenerate (WD-WD merger) scenarios. In recent years it was suggested that WD-WD direct collisions provide an additional channel for such explosions. Here we extend the studies of such explosions, and explore the role of Helium-shells in affecting the thermonuclear explosions. We study both the impact of low-mass helium ($\\sim0.01$ M$_{\\odot})$ shells, as well as high mass shells ($\\ge0.1$ M$_{\\odot}$). We find that detonation of the massive helium layers precede the detonation of the WD Carbon-Oxygen (CO) bulk during the collision and can change the explosive evolution and outcomes for the cases of high mass He-shells. In particular, the He-shell detonation propagates on the WD surface and inefficiently burns material prior to the CO detonation that later follows in the central parts...

Papish, Oded

2015-01-01T23:59:59.000Z

442

Helium enhancements in globular cluster stars from Asymptotic Giant Branch star pollution  

E-Print Network (OSTI)

Using a chemical evolution model we investigate the intriguing suggestion that there are populations of stars in some globular clusters (e.g. NGC 2808, omega Centauri) with enhanced levels of helium (Y from about 0.28 to 0.40) compared to the majority of the population that presumably have a primordial helium abundance. We assume that a previous generation of massive low-metallicity Asymptotic Giant Branch (AGB) stars has polluted the cluster gas via a slow stellar wind. We use two independent sets of AGB yields computed from detailed models to follow the evolution of helium, carbon, nitrogen and oxygen in the cluster gas using a Salpeter initial mass function (IMF) and a number of top-heavy IMFs. In no case were we able to fit the observational constraints, Y > 0.30 and C+N+O approximately constant. Depending on the shape of the IMF and the yields, we either obtained Y approximately greater than 0.30 and large increases in C+N+O or Y < 0.30 and C+N+O approximately constant. These results suggest that eith...

Karakas, A I; Sills, A; Campbell, S; Lattanzio, J C; Karakas, Amanda; Fenner, Yeshe; Sills, Alison; Campbell, Simon; Lattanzio, John

2006-01-01T23:59:59.000Z

443

Laser Isotope Enrichment for Medical and Industrial Applications  

SciTech Connect

Laser Isotope Enrichment for Medical and Industrial Applications by Jeff Eerkens (University of Missouri), Jay Kunze (Idaho State University), and Leonard Bond (Idaho National Laboratory) The principal isotope enrichment business in the world is the enrichment of uranium for commercial power reactor fuels. However, there are a number of other needs for separated isotopes. Some examples are: 1) Pure isotopic targets for irradiation to produce medical radioisotopes. 2) Pure isotopes for semiconductors. 3) Low neutron capture isotopes for various uses in nuclear reactors. 4) Isotopes for industrial tracer/identification applications. Examples of interest to medicine are targets to produce radio-isotopes such as S-33, Mo-98, Mo-100, W-186, Sn-112; while for MRI diagnostics, the non-radioactive Xe-129 isotope is wanted. For super-semiconductor applications some desired industrial isotopes are Si-28, Ga-69, Ge-74, Se-80, Te-128, etc. An example of a low cross section isotope for use in reactors is Zn-68 as a corrosion inhibitor material in nuclear reactor primary systems. Neutron activation of Ar isotopes is of interest in industrial tracer and diagnostic applications (e.g. oil-logging). . In the past few years there has been a sufficient supply of isotopes in common demand, because of huge Russian stockpiles produced with old electromagnetic and centrifuge separators previously used for uranium enrichment. Production of specialized isotopes in the USA has been largely accomplished using old ”calutrons” (electromagnetic separators) at Oak Ridge National Laboratory. These methods of separating isotopes are rather energy inefficient. Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation repression. In this scheme a gas, of the selected isotopes for enrichment, is irradiated with a laser at a particular wavelength that would excite only one of the isotopes. The entire gas is subject to low temperatures sufficient to cause condensation on a cold surface. Those molecules in the gas that the laser excited are not as likely to condense as are the unexcited molecules. Hence the gas drawn out of the system will be enriched in the isotope that was excited by the laser. We have evaluated the relative energy required in this process if applied on a commercial scale. We estimate the energy required for laser isotope enrichment is about 20% of that required in centrifuge separations, and 2% of that required by use of "calutrons".

Leonard Bond

2006-07-01T23:59:59.000Z

444

The de Haas-van Alphen Effect in Enriched Tin Isotopes  

Science Journals Connector (OSTI)

The de Haas-van Alphen effect has been investigated in tin isotopes in the liquid helium temperature range, and no conclusive evidence has been found indicating a dependence of the effect upon atomic mass. However, some new features of the effect have been investigated which are interpreted as being caused by at least two independent groups of electrons. One group of electrons, having effective masses m3=1.1m0 (where m0 is the free electron mass) parallel to the tetragonal axis and m1=0.16m0 perpendicular to the tetragonal axis, and having a chemical potential of E0=0.25 electron volt, gives rise to short period oscillations in the magnetic susceptibility as the magnetic field is varied. A second group of electrons having a chemical potential E0=0.20 electron volts and for which the effective masses are not so clearly defined gives rise to longer period oscillations such that the observed de Haas-van Alphen oscillations exhibit beats between the long and short period terms.

Ted G. Berlincourt

1952-10-15T23:59:59.000Z

445

A View from the Bridge - DOE Perspective | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

A View from the Bridge - DOE Perspective A View from the Bridge - DOE Perspective Broad view of DOE's approach to addressing transportation sector oil dependence...

446

Mid-Blend Ethanol Fuels - Implementation Perspectives | Department...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Mid-Blend Ethanol Fuels - Implementation Perspectives Mid-Blend Ethanol Fuels - Implementation Perspectives Breakout Session 2: Frontiers and Horizons Session 2-B: End Use and Fuel...

447

Perspectives Regarding Diesel Engine Emissions Reduction in the...  

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

Perspectives Regarding Diesel Engine Emissions Reduction in the Northeast Perspectives Regarding Diesel Engine Emissions Reduction in the Northeast 2004 Diesel Engine Emissions...

448

2010 Emissions from an Electronics Perspective | Department of...  

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

10 Emissions from an Electronics Perspective 2010 Emissions from an Electronics Perspective 2005 Diesel Engine Emissions Reduction (DEER) Conference Presentations and Posters...

449

Geothermal R&D: The DOE Perspective | Department of Energy  

Energy Savers (EERE)

R&D: The DOE Perspective Geothermal R&D: The DOE Perspective Internation-Forum-Mexico.pdf More Documents & Publications GEA Geothermal Summit Presentation Lauren Boyd Geothermal...

450

It's Elemental - Isotopes of the Element Nitrogen  

NLE Websites -- All DOE Office Websites (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%

451

Radioactive isotopes in Danish drinking water  

E-Print Network (OSTI)

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

452

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.

453

Review of hydrogen isotope permeability through materials  

SciTech Connect

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

Steward, S.A.

1983-08-15T23:59:59.000Z

454

Mikhail Avilov Facility for Rare Isotope Beams  

E-Print Network (OSTI)

Challenges Chemical Challenges Radiation Challenges Summary #12; World-leading heavy ion accelerator facility for rare isotope science · Nuclear Structure · Nuclear Astrophysics · Fundamental Interactions Target vacuum vessel M. Avilov, May 2014 5th HP Targetry Workshop, FNAL, Slide 4 Target Beam dump Beam

McDonald, Kirk

455

Carbon IsotopesCarbon Isotopes A Short Course VU March, 2009  

E-Print Network (OSTI)

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

Miami, University of

456

Method of enhancing selective isotope desorption from metals  

DOE Patents (OSTI)

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

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

1984-01-01T23:59:59.000Z

457

Method of preparing mercury with an arbitrary isotopic distribution  

DOE Patents (OSTI)

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

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

1986-12-16T23:59:59.000Z

458

Method of preparing mercury with an arbitrary isotopic distribution  

DOE Patents (OSTI)

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

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

1986-01-01T23:59:59.000Z

459

19 - The human resources perspective  

Science Journals Connector (OSTI)

Publisher Summary Security convergence is often associated with the accompanying challenges of ensuring that people and people practices are equal to the task. This chapter describes the human resource challenges from the perspective of an organization, which is about to embark upon security convergence. It is noted that true security convergence of physical and IT security requires a leader, who possesses the appropriate talent, ability, and experience. Also, because only a limited number of organizations have converged their IT and physical security operations, there are still relatively few individuals with hands-on experience of leading security convergence. From an HR perspective, there are a number of specific challenges comprising this new world. No matter what the environment is, there are new threats, new demands, and new business drivers and an imperative to respond in order to survive and prosper, as well as to meet the appropriate legislative or governance challenges. Whether it is a need to meet the dictates of corporate governance, or the commercial imperative to protect proprietary information, or simply the need to maximize internal efficiencies, the challenge persists.

Dave Tyson

2007-01-01T23:59:59.000Z

460

Isotope selective near-resonant two-photon ionization of 41Ca isotope via the 4s11s 1S0 intermediate state  

Science Journals Connector (OSTI)

Isotope selective excitation of a 41Ca isotope using a near-resonant two-photon ionization scheme 4s2 1S0-->422.7924...

Sankari, M

2008-01-01T23:59:59.000Z

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

Diffusion of Kr Isotopes in Solid Ar  

Science Journals Connector (OSTI)

The diffusion coefficient D=D0e-Q0RT and isotope effect for Kr78 and Kr86 in solid Ar have been measured using a tracer technique. The activation energy QKr0 depends on the interchange parameter w, but is estimated to lie in the range 3500-3900 cal mole-1, with the most reliable w giving the lower value. Thus, the two calculated QKr0 (3853 and 4050 cal mole-1) for the vacancy mechanism using a two-body (12, 6) potential appear somewhat high, but in reasonable agreement with experiment. The isotope effect gives f?K?(D78D86-1)[(8678)12-1]=0.48±0.25 which, since QKr0?QAr0, suggests that ?K?0.6 for a single-vacancy mechanism. {Here f is the correlation factor and ?K?(?278?286-1)[(8678)12-1], where ?2 is the tracer jump rate.}

E. H. C. PARKER; B. L. SMITH; H. R. GLYDE

1969-12-15T23:59:59.000Z

462

High-purity, isotopically enriched bulk silicon  

SciTech Connect

The synthesis and characterization of dislocation-free, undoped, single crystals of Si enriched in all 3 stable isotopes is reported: {sup 28}Si (99.92%), {sup 29}Si (91.37%), and {sup 30}Si (89.8%). A silane-based process compatible with the relatively small amounts of isotopically enriched precursors that are practically available was used. The silane is decomposed to silicon on a graphite starter rod heated to 700-750 C in a recirculating flow reactor. A typical run produces 35 gm of polycrystalline Si at a growth rates of 5 {micro}m/min and conversion efficiency >95%. Single crystals are grown by the floating zone method and characterized by electrical and optical measurements. Concentrations of shallow dopants (P and B) are as low as mid-10{sup 13} cm{sup -3}. Concentrations of C and O lie below 10{sup 16} and 10{sup 15} cm{sup -3}, respectively.

Ager III, J.W.; Beeman, J.W.; Hansen, W.L.; Haller, E.E.; Sharp, I.D.; Liao, C.; Yang, A.; Thewalt, M.L.W.; Riemann, H.

2004-11-17T23:59:59.000Z

463

Anomalous isotopic composition of cosmic rays  

SciTech Connect

Recent measurements of nonsolar isotopic patterns for the elements neon and (perhaps) magnesium in cosmic rays are interpreted within current models of stellar nucleosynthesis. One possible explanation is that the stars currently responsible for cosmic-ray synthesis in the Galaxy are typically super-metal-rich by a factor of two to three. Other possibilities include the selective acceleration of certain zones or masses of supernovas or the enhancement of /sup 22/Ne in the interstellar medium by mass loss from red giant stars and planetary nebulas. Measurements of critical isotopic ratios are suggested to aid in distinguishing among the various possibilities. Some of these explanations place significant constraints on the fraction of cosmic ray nuclei that must be fresh supernova debris and the masses of the supernovas involved. 1 figure, 3 tables.

Woosley, S.E.; Weaver, T.A.

1980-06-20T23:59:59.000Z

464

Use of Multiple Reheat Helium Brayton Cycles to Eliminate the Intermediate Heat Transfer Loop for Advanced Loop Type SFRs  

SciTech Connect

The sodium intermediate heat transfer loop is used in existing sodium cooled fast reactor (SFR) plant design as a necessary safety measure to separate the radioactive primary loop sodium from the water of the steam Rankine power cycle. However, the intermediate heat transfer loop significantly increases the SFR plant cost and decreases the plant reliability due to the relatively high possibility of sodium leakage. A previous study shows that helium Brayton cycles with multiple reheat and intercooling for SFRs with reactor outlet temperature in the range of 510°C to 650°C can achieve thermal efficiencies comparable to or higher than steam cycles or recently proposed supercritical CO2 cycles. Use of inert helium as the power conversion working fluid provides major advantages over steam or CO2 by removing the requirement for safety systems to prevent and mitigate the sodium-water or sodium-CO2 reactions. A helium Brayton cycle power conversion system therefore makes the elimination of the intermediate heat transfer loop possible. This paper presents a pre-conceptual design of multiple reheat helium Brayton cycle for an advanced loop type SFR. This design widely refers the new horizontal shaft distributed PBMR helium power conversion design features. For a loop type SFR with reactor outlet temperature 550°C, the design achieves 42.4% thermal efficiency with favorable power density comparing with high temperature gas cooled reactors.

Haihua Zhao; Hongbin Zhang; Samuel E. Bays

2009-05-01T23:59:59.000Z

465

Diffusional exchange of isotopes in a metal hydride sphere.  

SciTech Connect

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

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

2011-04-01T23:59:59.000Z

466

PERSPECTIVES  

Science Journals Connector (OSTI)

...5 and #6 at Fukushima Daiichi. One of the three emergency diesel generators installed at Unit 6 remained available, and operators...underscores the inherently fragile nature of the international oil market, which can potentially affect the world economy. Naturally...

467

Perspective  

NLE Websites -- All DOE Office Websites (Extended Search)

considered as the first scale. Aggregate can be separated in a mortar scale including sand and a concrete scale including coarse aggregate. The result of this two-step is an...

468

PERSPECTIVE  

Science Journals Connector (OSTI)

...as well as the contamination of local aquifers via underground methane leakage (see...importance of preventing contamination of aquifers and/or methane leakage and identify...environ- mental costs and benefits of fracking. Annual Review of Environment and Resources...

469

PERSPECTIVES  

Science Journals Connector (OSTI)

...technology. The two blocs in the Cold War, one led by the United States and Europe the other led by the Soviet Union, were in a nuclear arms...problem. Our new refrigerators and compact fluorescent bulbs consume one quarter as much power as the devices...

470

PERSPECTIVE  

Science Journals Connector (OSTI)

...assessed. Social impacts can be significant...mation of a rural environment into a temporary...mitigation of impacts are being made...environmental impacts. As we noted...and benefits of fracking. Annual Review of Environment and Resources...

471

PERSPECTIVE  

Science Journals Connector (OSTI)

...the cumu- lative impacts of energy-efficiency...THE ENVIRONMENTAL IMPACTS OF SHALE GAS DEVELOPMENT...associated environmental impacts. As we noted at the...costs and benefits of fracking. Annual Review of Environment and Resources 39...

472

PERSPECTIVES  

Science Journals Connector (OSTI)

...reconsideration of Japan's nuclear fuel cycle policy...reprocessing of spent nuclear fuel, and final...Rokkasho reprocessing plant, there was already...about the current nuclear fuel cycle strategy...development of nuclear power in Japan have changed...natural disasters and terrorism will be a crucial...

473

PERSPECTIVES  

Science Journals Connector (OSTI)

...global nuclear power depends on...realistic assessments are made...emeritus of nuclear engineering...the nuclear power plants and environmental...the health risks in areas...reprocessing plant, there was...the current nuclear fuel cycle...of nuclear power in Japan...disasters and terrorism will be a...reducing the risk of proliferating...

474

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

SciTech Connect

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

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

2010-09-09T23:59:59.000Z

475

A passively-safe fusion reactor blanket with helium coolant and steel structure  

SciTech Connect

Helium is attractive for use as a fusion blanket coolant for a number of reasons. It is neutronically and chemically inert, nonmagnetic, and will not change phase during any off-normal or accident condition. A significant disadvantage of helium, however, is its low density and volumetric heat capacity. This disadvantage manifests itself most clearly during undercooling accident conditions such as a loss of coolant accident (LOCA) or a loss of flow accident (LOFA). This thesis describes a new helium-cooled tritium breeding blanket concept which performs significantly better during such accidents than current designs. The proposed blanket uses reduced-activation ferritic steel as a structural material and is designed for neutron wall loads exceeding 4 MW/m{sup 2}. The proposed geometry is based on the nested-shell concept developed by Wong, but some novel features are used to reduce the severity of the first wall temperature excursion. These features include the following: (1) A ``beryllium-joint`` concept is introduced, which allows solid beryllium slabs to be used as a thermal conduction path from the first wall to the cooler portions of the blanket. The joint concept allows for significant swelling of the beryllium (10 percent or more) without developing large stresses in the blanket structure. (2) Natural circulation of the coolant in the water-cooled shield is used to maintain shield temperatures below 100 degrees C, thus maintaining a heat sink close to the blanket during the accident. This ensures the long-term passive safety of the blanket.

Crosswait, K.M.

1994-04-01T23:59:59.000Z

476

NEUTRAL INTERSTELLAR HELIUM PARAMETERS BASED ON IBEX-Lo OBSERVATIONS AND TEST PARTICLE CALCULATIONS  

SciTech Connect

Because of its high ionization potential and weak interaction with hydrogen, neutral interstellar helium (NISHe) is almost unaffected at the heliospheric interface with the interstellar medium and freely enters the solar system. This second most abundant species provides some of the best information on the characteristics of the interstellar gas in the local interstellar cloud. The Interstellar Boundary Explorer (IBEX) is the second mission to directly detect NISHe. We present a comparison between recent IBEX NISHe observations and simulations carried out using a well-tested quantitative simulation code. Simulation and observation results compare well for times when measured fluxes are dominated by NISHe (and contributions from other species are small). Differences between simulations and observations indicate a previously undetected secondary population of neutral helium, likely produced by interaction of interstellar helium with plasma in the outer heliosheath. Interstellar neutral parameters are statistically different from previous in situ results obtained mostly from the GAS/Ulysses experiment, but they do agree with the local interstellar flow vector obtained from studies of interstellar absorption: the newly established flow direction is ecliptic longitude 79.{sup 0}2, latitude -5.{sup 0}1, the velocity is {approx}22.8 km s{sup -1}, and the temperature is 6200 K. These new results imply a markedly lower absolute velocity of the gas and thus significantly lower dynamic pressure on the boundaries of the heliosphere and different orientation of the Hydrogen Deflection Plane compared to prior results from Ulysses. A different orientation of this plane also suggests a new geometry of the interstellar magnetic field, and the lower dynamic pressure calls for a compensation by other components of the pressure balance, most likely a higher density of interstellar plasma and strength of interstellar magnetic field.

Bzowski, M.; Kubiak, M. A.; Sokol, J. M.; Hlond, M. [Space Research Centre PAS, Warsaw (Poland); Moebius, E.; Bochsler, P.; Leonard, T.; Heirtzler, D.; Kucharek, H.; Schwadron, N. A. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH (United States); Crew, G. B. [Haystack Observatory, Massachusetts Institute of Technology, Westford, MA (United States); Fuselier, S. A. [Lockheed Martin, Space Physics Lab, 3251 Hanover Street, Palo Alto, CA 94304 (United States); McComas, D. J., E-mail: stephen.a.fuselier@linco.com [Southwest Research Institute, San Antonio, TX (United States)

2012-02-01T23:59:59.000Z

477

Polarization study of the extreme-ultraviolet emission from helium following electron impact  

Science Journals Connector (OSTI)

Experimental results are presented on the degree of linear polarization of the extreme-ultraviolet emission of neutral and ionized helium following electron-impact excitation and ionization excitation of helium. The polarization of the photon emission from the decay of He (1snp) 1Po states with wavelengths of 517 to 584 Å has been extended to electron-impact energies of 1500 eV, and compared with theory for electron-impact excitation of neutral helium. In addition, the polarization of a number of the He+ decays with wavelengths between 256 and 1640 Å have been measured. Particular attention has been paid to the (2p) 2Po?(1s) 2S and (3p) 2Po?(1s) 2S decays with wavelengths of 304 and 256 Å, respectively. These have been measured from threshold (66 and 73 eV, respectively) to 1500 eV using a characterized molybdenum/silicon multilayer mirror polarimeter whose reflection and polarization characteristics have been optimized at 304 Å He+(2p) 2Po results are compared with a recent threshold alignment measurement and distorted-wave Born-approximation calculation for the (e-,2e-) reaction of ionization excitation. Very good agreement with the threshold theoretical predictions is obtained. These results indicate that near threshold, partial waves with L>0 contribute substantially to the two-electron wave function of the escaping electrons. Measurements on the unresolved multiplets at 1215 and 1640 Å, made using a more conventional reflection-type polarization analyzer, indicate that relative fine-structure cross sections are quite different than predicted by some theories.

H. Merabet, M. Bailey, R. Bruch, D. V. Fursa, I. Bray, J. W. McConkey, and P. Hammond

1999-08-01T23:59:59.000Z

478

High Flux Isotope Reactor power upgrade status  

SciTech Connect

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

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

1997-03-01T23:59:59.000Z

479

Sulfur-isotope separation by distillation  

SciTech Connect

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

Mills, T.R.

1982-01-01T23:59:59.000Z

480

Concerning the Facility for Rare Isotope Beams  

ScienceCinema (OSTI)

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

Symons, James

2013-05-29T23:59:59.000Z

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481

Thermal behavior of bovine serum albumin after exposure to barrier discharge helium plasma jet  

Science Journals Connector (OSTI)

Non-thermal plasma jets at atmospheric pressure are useful tools nowadays in plasma medicine. Various applications are tested such as cauterization coagulation wound healing natural and artificial surfaces decontamination and sterilization. In order to know more about the effects of gas plasma on biological supramolecules we exposed proteinpowders to a barrier discharge helium plasma jet. Then spectroscopic investigations were carried out in order to obtain information on protein secondary tertiary and quaternary structures. We obtained a reduction of the protein alpha-helix content after the plasma exposure and a different behavior for both thermal denaturation/renaturation kinetics and thermal aggregation process.

R. Jijie; V. Pohoata; I. Topala

2012-01-01T23:59:59.000Z

482

Quantum Cascade Laser Spectroscopy and Photoinduced Chemistry of Al–(CO)n Clusters in Helium Nanodroplets  

Science Journals Connector (OSTI)

Quantum Cascade Laser Spectroscopy and Photoinduced Chemistry of Al–(CO)n Clusters in Helium Nanodroplets ... Only aluminum carbonyl clusters of the form Al–(CO)n are observed in this study, and a future report will discuss the larger Alm–(CO)n species. ... The QCL frequency is tuned by rotating a grating with a stepper motor (0.01 cm–1 steps) or by scanning the cavity length continuously (?30 GHz tuning) by applying a 0–100 V sine wave ramp to a piezo element. ...

Tao Liang; Steven D. Flynn; Alexander M. Morrison; Gary E. Douberly

2011-05-26T23:59:59.000Z

483

Alignment of the 2p State of 2-Mev Amu Helium-Like Sulfur  

E-Print Network (OSTI)

PHYSICAL REVIEW A VOLUME 26, NUMBER 6 DECEMBER 1982 Alignment of the 2P state of 2-MeV/amu helium1ike sulfur D. A. Church, R. A. Kenefick, D.-W. Wang, * and R. L. Watson Department ofPhysics and Cyclotron Institute, Texas AckM University... occurring at lower collision energies which 26 3093 1982 The American Physical Society 3094 CHURCH, KENEFICK, WANG, AND WATSON 26 match outer-shell electron velocities may be useful in defining the atomic character of the total ion- target interaction...

Church, David A.; Kenefick, R. A.; Wang, D. W.; Watson, R. L.

1982-01-01T23:59:59.000Z

484

Kinetics of muonic helium in muon-catalyzed d-d and d-t fusion  

Science Journals Connector (OSTI)

An accurate kinetics treatment is applied to the muonic helium atoms formed by a muon’s sticking to the charged particle produced in muon-catalyzed d-d and d-t fusion. Cross sections for l- and n- changing transitions are included to describe density-dependent stripping and x-ray production. Coupled with recent accurate calculations of the initial sticking, the results are generally in very good agreement with experiments. The noteworthy exception is that the density dependence of the sticking is much weaker than previously observed, in agreement with preliminary results of a new experiment.

James S. Cohen

1987-04-06T23:59:59.000Z

485

Lattice-Boltzmann simulation of laser interaction with weakly ionized helium plasmas  

SciTech Connect

This paper presents a lattice Boltzmann method for laser interaction with weakly ionized plasmas considering electron impact ionization and three-body recombination. To simulate with physical properties of plasmas, the authors' previous work on the rescaling of variables is employed and the electromagnetic fields are calculated from the Maxwell equations by using the finite-difference time-domain method. To calculate temperature fields, energy equations are derived separately from the Boltzmann equations. In this way, we attempt to solve the full governing equations for plasma dynamics. With the developed model, the continuous-wave CO{sub 2} laser interaction with helium is simulated successfully.

Li Huayu; Ki, Hyungson [Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan 48824-1226 (United States); School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2010-07-15T23:59:59.000Z

486

Fabrication of carbon nanotube nanogap electrodes by helium ion sputtering for molecular contacts  

SciTech Connect

Carbon nanotube nanogaps have been used to contact individual organic molecules. However, the reliable fabrication of a truly nanometer-sized gap remains a challenge. We use helium ion beam lithography to sputter nanogaps of only (2.8 ± 0.6) nm size into single metallic carbon nanotubes embedded in a device geometry. The high reproducibility of the gap size formation provides a reliable nanogap electrode testbed for contacting small organic molecules. To demonstrate the functionality of these nanogap electrodes, we integrate oligo(phenylene ethynylene) molecular rods, and measure resistance before and after gap formation and with and without contacted molecules.

Thiele, Cornelius, E-mail: Cornelius.Thiele@kit.edu [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany) [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); DFG Center for Functional Nanostructures (CFN), 76028 Karlsruhe (Germany); Vieker, Henning; Beyer, André; Gölzhäuser, Armin [Faculty of Physics, Bielefeld University, 33615 Bielefeld (Germany)] [Faculty of Physics, Bielefeld University, 33615 Bielefeld (Germany); Flavel, Benjamin S.; Hennrich, Frank [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany)] [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); Muñoz Torres, David; Eaton, Thomas R. [Department of Chemistry, University of Basel, 4056 Basel (Switzerland)] [Department of Chemistry, University of Basel, 4056 Basel (Switzerland); Mayor, Marcel [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany) [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); DFG Center for Functional Nanostructures (CFN), 76028 Karlsruhe (Germany); Department of Chemistry, University of Basel, 4056 Basel (Switzerland); Kappes, Manfred M. [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany) [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); DFG Center for Functional Nanostructures (CFN), 76028 Karlsruhe (Germany); Institut für Physikalische Chemie, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Löhneysen, Hilbert v. [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany) [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); DFG Center for Functional Nanostructures (CFN), 76028 Karlsruhe (Germany); Physikalisches Institut, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Institut für Festkörperphysik, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); and others

2014-03-10T23:59:59.000Z

487

3D Numerical Experimentation on the Core Helium Flash of low-mass Red Giants  

E-Print Network (OSTI)

We model the core helium flash in a low-mass red giant using Djehuty, a fully three-dimensional (3D) code. The 3D structures were generated from converged models obtained during the 1D evolutionary calculation of a 1$\\Msun$ star. Independently of which starting point we adopted, we found that after some transient relaxation the 3D model settled down with a briskly convecting He-burning shell that was not very different from what the 1D model predicted.

David S. P. Dearborn; John C. Lattanzio; Peter P. Eggleton

2005-12-02T23:59:59.000Z

488

EVOLUTION OF THE STANDARD HELIUM LIQUEFIER AND REFRIGERATOR RANGE DESIGNED BY AIR LIQUIDE DTA, FRANCE.  

Science Journals Connector (OSTI)

The standard helium liquefier and refrigerator range called Helial and designed by Air Liquide DTA has recently been upgraded in order to improve the efficiency of these machines. Indeed over the multi-range markets requiring these cryogenic systems (international laboratories aerospace applications synchrotrons HTS applications…) the technological solution has to provide increasingly high performances. The new Helial Evolution range equipped with very reliable DTA turbo-expanders constitutes a highly efficient product for this wide application field. The optimizations adaptations and results of the Helial Evolution series doubling the performance for the same power consumption will be presented.

A. Caillaud; S. Crispel; V. Grabié; G. Aigouy

2008-01-01T23:59:59.000Z

489

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

E-Print Network (OSTI)

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

Grossman, Lawrence

490

Word Pro - Perspectives.lwp  

Gasoline and Diesel Fuel Update (EIA)

2 2 xvii Energy Perspectives 18.97 in 1970 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 0 30 60 90 120 Quadrillion Btu Figure 1. Energy Overview The United States was self-sufficient in energy until the late 1950s when energy consumption began to outpace domestic production. The Nation imported more energy to fill the gap. In 2002, net imported energy accounted for 26 percent of all energy consumed. Figure 1. Energy Overview Overview Exports Production Imports Consumption 1950 1960 1970 1980 1990 2000 0 5 10 15 20 25 per Chained (1996) Dollar Thousand Btu Figure 3. Energy Use per Dollar of Gross Domestic Product Over the second half of the 20th century, the rate at which energy was consumed per dollar of the economy's output of goods and services fell dramatically. By the end of the century, the rate was half of the mid-century

491

Word Pro - Perspectives.lwp  

Gasoline and Diesel Fuel Update (EIA)

7 7 xix Energy Perspectives 18.97 in 1970 1950 1960 1970 1980 1990 2000 0 20 40 60 80 100 120 Quadrillion Btu The United States was self-sufficient in energy until the late 1950s when energy consumption began to outpace domestic production. At that point, the Nation began to import more energy to fill the gap. In 2007, net imported energy accounted for 29 percent of all energy consumed. Figure 1. Primary Energy Overview Overview Exports Production Imports Consumption 1950 1960 1970 1980 1990 2000 0 5 10 15 20 25 Thousand Btu per Chained (2000) Dolla Figure 3. Energy Use per Dollar of Gross Domestic Product After 1970, the amount of energy consumed to produce a dollar's worth of the Nation's output of goods and services trended down. The decline resulted from efficiency improvements and structural changes in the econ-

492

Word Pro - Perspectives.lwp  

Gasoline and Diesel Fuel Update (EIA)

Annual Energy Review 2009 Annual Energy Review 2009 xix 1950 1960 1970 1980 1990 2000 0 20 40 60 80 100 120 Quadrillion Btu The United States was self-sufficient in energy until the late 1950s when energy consumption began to outpace domestic production. At that point, the Nation began to import more energy to meet its needs. In 2009, net imported energy accounted for 24 percent of all energy consumed. Figure 1. Primary Energy Overview Energy Perspectives Overview Exports Production Imports Consumption 1950 1960 1970 1980 1990 2000 0 5 10 15 20 25 Thousand Btu per Chained (2005) Dolla Figure 3. Energy Use per Dollar of Gross Domestic Product After 1970, the amount of energy consumed to produce a dollar's worth of the Nation's output of goods and services trended down. The decline resulted from efficiency improvements and structural changes in the econ-

493

Board Staff Perspectives Quality Council  

NLE Websites -- All DOE Office Websites (Extended Search)

Nuclear Facilities Safety Nuclear Facilities Safety Board Th B d & T h i l S ff Q li A The Board & Technical Staff Quality Assurance Perspectives for 2011 2010 Dr. W. San Horton, PMP, CSQE Member of the Technical Staff Defense Nuclear Facilities Safety Board DISCLAIMER The ie s and opinions presented are solel the a thor's No information contained in the presentation nor an associated The views and opinions presented are solely the author's. No information contained in the presentation nor any associated discussion should be construed as official or unofficial views or positions of the Defense Nuclear Facilities Safety Board Defense Nuclear Facilities Safety Board T i Topics B i I f ti B d * Basic Information on Board * Who, what, mission, size, location * Organization of the Board and the Board's staff

494

Word Pro - Perspectives.lwp  

Gasoline and Diesel Fuel Update (EIA)

6 6 xix Energy Perspectives 18.97 in 1970 1950 1960 1970 1980 1990 2000 0 20 40 60 80 100 120 Quadrillion Btu The United States was self-sufficient in energy until the late 1950s when energy consumption began to outpace domestic production. At that point, the Nation began to import more energy to fill the gap. In 2006, net imported energy accounted for 30 percent of all energy consumed. Figure 1. Energy Overview Overview Exports Production Imports Consumption 1950 1960 1970 1980 1990 2000 0 5 10 15 20 25 Thousand Btu per Chained (2000) Dolla Figure 3. Energy Use per Dollar of Gross Domestic Product After 1970, the amount of energy consumed to produce a dollar's worth of the Nation's output of goods and services trended down. The decline resulted from efficiency improvements and structural changes in the econ-

495

The torque dependence of the H-mode power threshold in hydrogen, deuterium and helium plasmas in DIII-D  

SciTech Connect

On DIII-D, the H-mode power threshold has been determined for hydrogen, deuterium and helium plasmas heated by neutral beam injection and/or by electron cyclotron heating and as a function of the applied torque plasmas for plasma configurations in the favourable ion grad-B drift direction. The H-mode threshold power has been determined to increase with input torque for all the main ion species (hydrogen, deuterium and helium). The H-mode threshold power for similar plasma parameters and configurations is the least for deuterium, followed by helium and hydrogen in that order. The plasma geometry also affects the power threshold, which is dependent on the X-point height.

Gohil, P. [General Atomics; Jernigan, T. C. [Oak Ridge National Laboratory (ORNL); Osborne, T.H. [General Atomics, San Diego; Scoville, J. T. [General Atomics, San Diego; Strait, E. J. [General Atomics

2010-01-01T23:59:59.000Z

496

Design and test of a wet type helium turbo-expander with an alternator as a brake  

SciTech Connect

A wet type helium turbo-expander with expected adiabatic efficiency of 70% at inlet pressure, temperature, and outlet pressure of 1.3 MPa, 6.0 K, and 0.2 MPa, respectively, has been developed. An alternator is adopted as a brake where a permanent magnet is held in the turbine shaft. And a self-acting gas bearing is used at thrust and journal bearings. An electromagnet supports thrust bearing to lift up the thrust disk when initiating operation. Design mass flow rate of the turbine is determined to be 60 g/s, corresponding to the JT mass flow rate in the existing helium liquefier/refrigerator. In the cryogenic performance test, the turbine had increased helium liquefaction rate by four times larger than the liquefaction rate without turbine operation.

Kato, T.; Miyake, A.; Kawano, K.; Hamada, K.; Hiyama, T.; Iwamoto, S.; Ebisu, H.; Tsuji, H. [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan); Saji, N.; Kaneko, Y. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)] [and others

1994-12-31T23:59:59.000Z

497

Ab initio Equation of State data for hydrogen, helium, and water and the internal structure of Jupiter  

E-Print Network (OSTI)

The equation of state of hydrogen, helium, and water effects interior structure models of giant planets significantly. We present a new equation of state data table, LM-REOS, generated by large scale quantum molecular dynamics simulations for hydrogen, helium, and water in the warm dense matter regime, i.e.for megabar pressures and temperatures of several thousand Kelvin, and by advanced chemical methods in the complementary regions. The influence of LM-REOS on the structure of Jupiter is investigated and compared with state-of-the-art results within a standard three-layer model consistent with astrophysical observations of Jupiter. Our new Jupiter models predict an important impact of mixing effects of helium in hydrogen with respect to an altered compressibility and immiscibility.

N. Nettelmann; B. Holst; A. Kietzmann; M. French; R. Redmer; D. Blaschke

2007-12-06T23:59:59.000Z

498

Measurement of quasi-isentropic compressibility of helium and deuterium at pressures of 1500-2000 GPa  

SciTech Connect

The quasi-isentropic compressibility of helium and deuterium plasmas at pressures of up to 1500-2000 GPa has been measured using devices with spherical geometry and an X-ray diagnostic complex comprising three betatrons and a multichannel imaging system with electro-optic gamma detectors. A deuterium density of 4.5 g/cm{sup 3} and a helium density of 3.8 g/cm{sup 3} have been obtained at pressures of 2210 and 1580 GPa, respectively. The internal energy of a deuterium plasma at the indicated pressure is about 1 MJ/cm{sup 3}, which is about 100 times greater than the specific energy of condensed chemical explosives. Analysis of the obtained data shows that the degree of helium ionization under the achieved plasma compression parameters is about 0.9.

Mochalov, M. A., E-mail: postmaster@ifv.vniief.ru; Il'kaev, R. I. [Russian Federal Nuclear Center, All-Russia Institute of Experimental Physics (Russian Federation); Fortov, V. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Mikhailov, A. L.; Makarov, Yu. M.; Arinin, V. A.; Blikov, A. O.; Baurin, A. Yu.; Komrakov, V. A.; Ogorodnikov, V. A.; Ryzhkov, A. V.; Pronin, E. A.; Yukhimchuk, A. A. [Russian Federal Nuclear Center, All-Russia Institute of Experimental Physics (Russian Federation)

2012-10-15T23:59:59.000Z

499

Effect of superfluid helium at the inner coil face on cooling and stability in superconducting accelerator magnets  

Science Journals Connector (OSTI)

For the upcoming luminosity upgrade of CERN's Large Hadron Collider a main issue is to increase the effective heat removal from the superconducting cables in the final focusing quadrupole magnets. The focus here is on the effect of superfluid helium in the thin annular space between the windings and the beam pipe which is studied using finite element modeling. Below the lambda temperature the effect of helium is described by an effective thermal conductivity. The temperature distribution is strongly dependent on the heat flux and therefore on the dimensions of the cooling channels and the spatial distribution of the heat source. Especially the influence of the so-called ground-insulation flaps partly blocking helium flow in the annulus is of interest. For a high energy deposition the flaps are a limiting factor. A solution is to implement a corrugated edged flap such that openings exist while sufficient electrical insulation is maintained.

2012-01-01T23:59:59.000Z

500

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