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Sample records for noble gases he-kr

  1. Noble Gases

    NASA Astrophysics Data System (ADS)

    Podosek, F. A.

    2003-12-01

    The noble gases are the group of elements - helium, neon, argon, krypton, xenon - in the rightmost column of the periodic table of the elements, those which have "filled" outermost shells of electrons (two for helium, eight for the others). This configuration of electrons results in a neutral atom that has relatively low electron affinity and relatively high ionization energy. In consequence, in most natural circumstances these elements do not form chemical compounds, whence they are called "noble." Similarly, much more so than other elements in most circumstances, they partition strongly into a gas phase (as monatomic gas), so that they are called the "noble gases" (also, "inert gases"). (It should be noted, of course, that there is a sixth noble gas, radon, but all isotopes of radon are radioactive, with maximum half-life a few days, so that radon occurs in nature only because of recent production in the U-Th decay chains. The factors that govern the distribution of radon isotopes are thus quite different from those for the five gases cited. There are interesting stories about radon, but they are very different from those about the first five noble gases, and are thus outside the scope of this chapter.)In the nuclear fires in which the elements are forged, the creation and destruction of a given nuclear species depends on its nuclear properties, not on whether it will have a filled outermost shell when things cool off and nuclei begin to gather electrons. The numerology of nuclear physics is different from that of chemistry, so that in the cosmos at large there is nothing systematically special about the abundances of the noble gases as compared to other elements. We live in a very nonrepresentative part of the cosmos, however. As is discussed elsewhere in this volume, the outstanding generalization about the geo-/cosmochemistry of the terrestrial planets is that at some point thermodynamic conditions dictated phase separation of solids from gases, and that the

  2. Noble gases in the moon

    NASA Technical Reports Server (NTRS)

    Manuel, O. K.; Srinivasan, B.; Hennecke, E. W.; Sinclair, D. E.

    1972-01-01

    The abundance and isotopic composition of helium, neon, argon, krypton, and xenon which were released by stepwise heating of lunar fines (15601.64) and (15271.65) were measured spectrometrically. The results of a composition of noble gases released from the lunar fines with noble gases in meteorites and in the earth are presented along with the isotopic composition of noble gases in lunar fines, in meteorites, and in the atmosphere. A study of two isotopically distinct components of trapped xenon in carbonaceous chondrites is also included.

  3. Single-bubble sonoluminescence from noble gases.

    PubMed

    Yasui, K

    2001-03-01

    Single-bubble sonoluminescence (SBSL) from noble gases in water is studied theoretically in order to clarify the reason of the distinguished feature that the luminescence is strong for all noble gases, while the other systems of cavitation luminescence are greatly enhanced by the presence of the heavy noble gas(xenon). It is clarified that in spite of the larger thermal conductivity of lighter noble gases the maximum temperature in a SBSL bubble of lighter noble gases is higher due both to the segregation of water vapor and noble gas inside a SBSL bubble and the stronger acoustic drive of a SBSL bubble of lighter noble gases.

  4. Single-bubble sonoluminescence from noble gases

    NASA Astrophysics Data System (ADS)

    Yasui, Kyuichi

    2001-03-01

    Single-bubble sonoluminescence (SBSL) from noble gases in water is studied theoretically in order to clarify the reason of the distinguished feature that the luminescence is strong for all noble gases, while the other systems of cavitation luminescence are greatly enhanced by the presence of the heavy noble gas(xenon). It is clarified that in spite of the larger thermal conductivity of lighter noble gases the maximum temperature in a SBSL bubble of lighter noble gases is higher due both to the segregation of water vapor and noble gas inside a SBSL bubble and the stronger acoustic drive of a SBSL bubble of lighter noble gases.

  5. Angular correlation studies in noble gases

    NASA Technical Reports Server (NTRS)

    Coleman, P. G.

    1990-01-01

    There has been a recent revival of interest in the measurement of angular correlation of annihilation photons from the decay of positrons and positronium in gases. This revival has been stimulated by the possibility offered by the technique to shed new light on the apparently low positronium formation fraction in the heavier noble gases and to provide information on positronium quenching processes in gases such as oxygen. There is also the potential for learning about positronium slowing down in gases. This review focuses on experimental noble gas work and considers what new information has been, and may be, gained from these studies.

  6. Preserving noble gases in a convecting mantle.

    PubMed

    Gonnermann, Helge M; Mukhopadhyay, Sujoy

    2009-05-28

    High (3)He/(4)He ratios sampled at many ocean islands are usually attributed to an essentially undegassed lower-mantle reservoir with high (3)He concentrations. A large and mostly undegassed mantle reservoir is also required to balance the Earth's (40)Ar budget, because only half of the (40)Ar produced from the radioactive decay of (40)K is accounted for by the atmosphere and upper mantle. However, geophysical and geochemical observations suggest slab subduction into the lower mantle, implying that most or all of Earth's mantle should have been processed by partial melting beneath mid-ocean ridges and hotspot volcanoes. This should have left noble gases in both the upper and the lower mantle extensively outgassed, contrary to expectations from (3)He/(4)He ratios and the Earth's (40)Ar budget. Here we suggest a simple solution: recycling and mixing of noble-gas-depleted slabs dilutes the concentrations of noble gases in the mantle, thereby decreasing the rate of mantle degassing and leaving significant amounts of noble gases in the processed mantle. As a result, even when the mass flux across the 660-km seismic discontinuity is equivalent to approximately one lower-mantle mass over the Earth's history, high (3)He contents, high (3)He/(4)He ratios and (40)Ar concentrations high enough to satisfy the (40)Ar mass balance of the Earth can be preserved in the lower mantle. The differences in (3)He/(4)He ratios between mid-ocean-ridge basalts and ocean island basalts, as well as high concentrations of (3)He and (40)Ar in the mantle source of ocean island basalts, can be explained within the framework of different processing rates for the upper and the lower mantle. Hence, to preserve primitive noble gas signatures, we find no need for hidden reservoirs or convective isolation of the lower mantle for any length of time.

  7. Noble Gases in the Chelyabinsk Meteorites

    NASA Technical Reports Server (NTRS)

    Haba, Makiko K.; Sumino, Hirochika; Nagao, Keisuke; Mikouchi, Takashi; Komatsu, Mutsumi; Zolensky, Michael E.

    2014-01-01

    The Chelyabinsk meteorite fell in Russia on February 15, 2013 and was classified as LL5 chondrite. The diameter before it entered the atmosphere has been estimated to be about 20 m [1]. Up to now, numerous fragments weighing much greater than 100 kg in total have been collected. In this study, all noble gases were measured for 13 fragments to investigate the exposure history of the Chelyabinsk meteorite and the thermal history of its parent asteroid.

  8. Fractionated (Martian) Noble Gases — EFA, Experiments and Meteorites

    NASA Astrophysics Data System (ADS)

    Schwenzer, S. P.; Barnes, G.; Bridges, J. C.; Bullock, M. A.; Chavez, C. L.; Filiberto, J.; Herrmann, S.; Hicks, L. J.; Kelley, S. P.; Miller, M. A.; Moore, J. M.; Ott, U.; Smith, H. D.; Steer, E. D.; Swindle, T. D.; Treiman, A. H.

    2016-08-01

    Noble gases are tracers for physical processes, including adsorption, dissolution and secondary mineral formation. We examine the Martian fractionated atmosphere through literature, terrestrial analogs and experiments.

  9. Where do noble gases hide in space?

    NASA Astrophysics Data System (ADS)

    Pauzat, F.; Ellinger, Y.

    Observations showing anomalous amounts of noble gas, especially in planetary atmospheres, are at the origin of a series of controversial interpretations from 1990 to nowadays (Hersant et al. (2004)). If, in a first step, we adopt a chemical point of view, we have to consider the possibility of associations of such elements (though usually considered as non reactive), with other molecules or atoms. Such complexes could trap the noble gases in some astrophysical objects at one time of their evolution, for example, in the early step of formation of protoplanetary disks. But two questions have to be answered to assert this type of hypothesis: which stable compounds could exist taking into account the environnement and which reactions could lead to such compounds? Hydrogen being by far the most abundant element in space, and neutral systems whose cohesion is driven by weak Van der Waals forces being unable to resist turbulence in space, the first and simplest association to consider is the one between the noble gas and the H3+ ion. Thus, DFT in the B3LYP, PW91 and BHandHLYP formalisms together with ab-initio methods of Coupled Cluster type have been employed to determine the equilibrium geometries, the spectroscopic constants and the bonding energies of the possible complexes between noble gases and hydrogen. We have first performed an extensive study of the associations ArnH3+ possible with Argon (the first noble gas which rose questions in the area of Jupiter's poles). We have found that several Argon atoms can be stabilized around the H3+ ion, the first complexation being in the plane of the ion. The spectroscopic data (rotational constants, dipole moments and IR signatures) were calculated (Pauzat & Ellinger (2005)) so that the laboratory experiments and spatial observations of these species could then be carried out. From our results and previous observations on this complex (Bogey et al. (1987)) we can say that the ArH3+ ion is certainly a good candidate for

  10. Selective Growth of Noble Gases at Metal/Oxide Interface.

    PubMed

    Takahashi, Keisuke; Oka, Hiroshi; Ohnuki, Somei

    2016-02-17

    The locations and roles of noble gases at an oxide/metal interface in oxide dispersed metal are theoretically and experimentally investigated. Oxide dispersed metal consisting of FCC Fe and Y2Hf2O7 (Y2Ti2O7) is synthesized by mechanical alloying under a saturated Ar gas environment. Transmission electron microscopy and density functional theory observes the strain field at the interface of FCC Fe {111} and Y2Hf2O7 {111} whose physical origin emerges from surface reconstruction due to charge transfer. Noble gases are experimentally observed at the oxide (Y2Ti2O7) site and calculations reveal that the noble gases segregate the interface and grow toward the oxide site. In general, the interface is defined as the trapping site for noble gases; however, transmission electron microscopy and density functional theory found evidence which shows that noble gases grow toward the oxide, contrary to the generally held idea that the interface is the final trapping site for noble gases. Furthermore, calculations show that the inclusion of He/Ar hardens the oxide, suggesting that material fractures could begin from the noble gas bubble within the oxides. Thus, experimental and theoretical results demonstrate that noble gases grow from the interface toward the oxide and that oxides behave as a trapping site for noble gases.

  11. Fullerenes and Noble Gases in the Murchison and Allende Meteorites

    NASA Technical Reports Server (NTRS)

    Becker, Luann; Poreda, Robert J.; Bunch, Ted E.

    2000-01-01

    In this work we report the detection of fullerenes (C60 to C250) in the Murchison and Allende meteorites. By exploiting the unique ability of these molecules to trap noble gases, we have determined that fullerene is indeed a new carrier phase for noble gases in meteorites.

  12. Ionization and Positronium Formation in Noble Gases

    NASA Astrophysics Data System (ADS)

    Marler, J. P.; Sullivan, J. P.; Surko, C. M.

    2006-11-01

    This paper reviews key results of our recent study [Marler et al., Phys. Rev. A 71, 022701 (2005)] of direct ionization and positronium formation in the noble gases from the thresholds for these processes to 90 eV. Results for argon and xenon are emphasized. The original study also reports similar results for neon and krypton. The experiment uses a cold, trap-based positron beam and scattering in a strong magnetic field to make absolute cross section measurements. Comparison with a detailed set of previous measurements yields reasonably good absolute agreement. A third, independent analysis was used to resolve the remaining discrepancies to a < 5% level in argon, krypton and xenon. Key aspects of the work, comparison with available theory, and open questions for future research are discussed.

  13. Biomedical imaging with hyperpolarized noble gases

    NASA Astrophysics Data System (ADS)

    Ruppert, Kai

    2014-11-01

    Hyperpolarized noble gases (HNGs), polarized to approximately 50% or higher, have led to major advances in magnetic resonance (MR) imaging of porous structures and air-filled cavities in human subjects, particularly the lung. By boosting the available signal to a level about 100 000 times higher than that at thermal equilibrium, air spaces that would otherwise appear as signal voids in an MR image can be revealed for structural and functional assessments. This review discusses how HNG MR imaging differs from conventional proton MR imaging, how MR pulse sequence design is affected and how the properties of gas imaging can be exploited to obtain hitherto inaccessible information in humans and animals. Current and possible future imaging techniques, and their application in the assessment of normal lung function as well as certain lung diseases, are described.

  14. Sir William Ramsay and the noble gases.

    PubMed

    Davies, Alwyn G

    2012-01-01

    Sir William Ramsay was one of the world's leading scientists at the end of the 19th century, and in a spectacular period of research between 1894 and 1898, he discovered five new elements. These were the noble gases, helium, neon, argon, krypton, and xenon; they added a whole new group to the Periodic Table of the elements, and provided the keystone to our understanding of the electronic structure of atoms, and the way those electrons bind the atoms together into molecules. For this work he was awarded the Nobel Prize in Chemistry in 1904, the first such prize to come to a British subject. He was also a man of great charm, a good linguist, and a composer and performer of music, poetry and song. This review will trace his career, describe his character and give and account of the chemistry which led to the award of the Nobel Prize.

  15. Solubility of noble gases in serpentine - Implications for meteoritic noble gas abundances

    NASA Technical Reports Server (NTRS)

    Zaikowski, A.; Schaeffer, O. A.

    1979-01-01

    An investigation of the solubilities of the noble gases from synthesis and solubility studies of the sheet silicate mineral serpentine in carbonaceous chondrites is presented. Hydrothermal synthesis and exchange experiments were made at 340C and 1 kbar with noble gas partial pressures from 2 times 10 to the -8th power to 0.1 atm. The measured distribution coefficients for noble gases are not sufficiently high to account for the trapped noble gases in carbonaceous chondrites by exchange in solar nebula if meteoritic minerals have comparable distribution coefficients. Also, serpentine gains and loses noble gases to approach equilibrium values with the terrestrial atmosphere, indicating that this exposure may have influenced the noble gas abundances in phyllosilicate minerals of these chondrites. The dispersion of K-Ar ages of carbonaceous chondrites could be the result of phyllosilicates approaching equilibrium solubility of atmospheric Ar-40.

  16. The Noble Gases in A-Level Chemistry.

    ERIC Educational Resources Information Center

    Marchant, G. W.

    1983-01-01

    Suggests two methods of developing the study of the noble gases: first, the discovery of the elements and recent discovery of xenon show the human face of chemistry (historical development); second, the properties of noble gas compounds (particularly xenon) can be used to test the framework of conventional chemistry. (Author/JM)

  17. The diverse biological properties of the chemically inert noble gases.

    PubMed

    Winkler, David A; Thornton, Aaron; Farjot, Géraldine; Katz, Ira

    2016-04-01

    The noble gases represent an intriguing scientific paradox. They are extremely inert chemically but display a remarkable spectrum of clinically useful biological properties. Despite a relative paucity of knowledge of their mechanisms of action, some of the noble gases have been used successfully in the clinic. Studies with xenon have suggested that the noble gases as a class may exhibit valuable biological properties such as anaesthesia; amelioration of ischemic damage; tissue protection prior to transplantation; analgesic properties; and a potentially wide range of other clinically useful effects. Xenon has been shown to be safe in humans, and has useful pharmacokinetic properties such as rapid onset, fast wash out etc. The main limitations in wider use are that: many of the fundamental biochemical studies are still lacking; the lighter noble gases are likely to manifest their properties only under hyperbaric conditions, impractical in surgery; and administration of xenon using convectional gaseous anaesthesia equipment is inefficient, making its use very expensive. There is nonetheless a significant body of published literature on the biochemical, pharmacological, and clinical properties of noble gases but no comprehensive reviews exist that summarize their properties and the existing knowledge of their models of action at the molecular (atomic) level. This review provides such an up-to-date summary of the extensive, useful biological properties of noble gases as drugs and prospects for wider application of these atoms.

  18. Photosensitive dopants for liquid noble gases

    DOEpatents

    Anderson, David F.

    1988-01-01

    In an ionization type detector for high energy radiation wherein the energy of incident radiation is absorbed through the ionization of a liquid noble gas and resulting free charge is collected to form a signal indicative of the energy of the incident radiation, an improvement comprising doping the liquid noble gas with photosensitive molecules to convert scintillation light due to recombination of ions, to additional free charge.

  19. Fullerenes: A New Carrier Phase for Noble Gases in Meteorites

    NASA Technical Reports Server (NTRS)

    Becker, Luann

    2004-01-01

    The major focus of our research effort has been to measure the noble gases encapsulated within fullerenes, a new carbon carrier phase and compare it to the myriad of components found in the bulk meteorite acid residues. We have concentrated on the carbonaceous chondrites (Allende, Murchison and Tagish Lake) since they have abundant noble gases, typically with a planetary signature that dominates the stepped-release of the meteorite bulk acid residue. They also contain an extractable fullerene component that can be isolated and purified from the same bulk material.

  20. Investigation of radioactive noble gases distribution in atmosphere

    SciTech Connect

    Achkasov, S.K.; Duginets, G.A.; Krylov, A.Yu.

    1993-12-31

    This report describes two tasks pertaining to the study of radioactive noble gases in the atmosphere: research of global effects, and using the results of measurements of the concentrations in the atmosphere as a specific tool for control of environmental radiation condition near nuclear facilities.

  1. Noble Gases in the Hamlet Meteorite (LL4)

    NASA Astrophysics Data System (ADS)

    Amari, S.; Sabe, Y.; Shiraishi, T.; Matsuda, J.

    2014-09-01

    We analyzed noble gases in a bulk sample and an HF-HCl residue of Hamlet (LL4). The Xe composition of the residue shows that no diamond is contained in the residue. The 20Ne/22Ne ratio of Hamlet Ne-Q has been determined to be 11.0 ± 0.5.

  2. Impact degassing of water and noble gases from silicates

    NASA Technical Reports Server (NTRS)

    Azuma, S.; Hiyagon, H.; Iijima, Y.; Syono, Y.

    1994-01-01

    Previous shock experiments by Ahrens and his colleagues show that degassing of H2O and CO2 occurs at 8-65GPa from hydrous minerals such as serpentine. In early solar system, the impact degassing would have played an important part in the formation of primary-atmospheres of the terrestrial planets. However, degassing conditions of noble gases are not well-known because there are few experiments for them. We conducted some shock recovery experiments to investigate the degassing condition and to understand the degassing mechanisms of water and noble gases. We used natural richterites (Ri), amphibolites (Am), serpentines (Sep) and orthoclases (or) as target samples. These, except Sep, contain radiogenic noble gases such as (40)Ar. The samples were put in stainless steel containers, and were show by a rail gun at ISAS or single-stage powder guns at Nagoya or Tohoku University, Japan. We used two kinds of containers: 'open' type containers having a ventilating path for released volatiles for most of samples and 'closed' type ones for some samples for comparison. On Ri and Sep, we made shock experiments for pre-heated (at 400-500 C) and unheated targets, and for powdered and uncrushed samples. Water and noble gases were analyzed both for the recovered shocked samples and the unshocked original samples, and the fractions of the degassed volatiles were calculated by comparing them. Water content in the sample was analyzed by thermo-gravimetry. Noble gases were extracted by heating the samples under high vacuum and analyzed with a sector-type mass spectrometer.

  3. Impact degassing of water and noble gases from silicates

    NASA Astrophysics Data System (ADS)

    Azuma, S.; Hiyagon, H.; Iijima, Y.; Syono, Y.

    Previous shock experiments by Ahrens and his colleagues show that degassing of H2O and CO2 occurs at 8-65GPa from hydrous minerals such as serpentine. In early solar system, the impact degassing would have played an important part in the formation of primary-atmospheres of the terrestrial planets. However, degassing conditions of noble gases are not well-known because there are few experiments for them. We conducted some shock recovery experiments to investigate the degassing condition and to understand the degassing mechanisms of water and noble gases. We used natural richterites (Ri), amphibolites (Am), serpentines (Sep) and orthoclases (or) as target samples. These, except Sep, contain radiogenic noble gases such as (40)Ar. The samples were put in stainless steel containers, and were show by a rail gun at ISAS or single-stage powder guns at Nagoya or Tohoku University, Japan. We used two kinds of containers: 'open' type containers having a ventilating path for released volatiles for most of samples and 'closed' type ones for some samples for comparison. On Ri and Sep, we made shock experiments for pre-heated (at 400-500 C) and unheated targets, and for powdered and uncrushed samples. Water and noble gases were analyzed both for the recovered shocked samples and the unshocked original samples, and the fractions of the degassed volatiles were calculated by comparing them. Water content in the sample was analyzed by thermo-gravimetry. Noble gases were extracted by heating the samples under high vacuum and analyzed with a sector-type mass spectrometer.

  4. Fluid clathrate system for continuous removal of heavy noble gases from mixtures of lighter gases

    DOEpatents

    Gross, Kenneth C.; Markun, Francis; Zawadzki, Mary T.

    1998-01-01

    An apparatus and method for separation of heavy noble gas in a gas volume. An apparatus and method have been devised which includes a reservoir containing an oil exhibiting a clathrate effect for heavy noble gases with a reservoir input port and the reservoir is designed to enable the input gas volume to bubble through the oil with the heavy noble gas being absorbed by the oil exhibiting a clathrate effect. The gas having reduced amounts of heavy noble gas is output from the oil reservoir, and the oil having absorbed heavy noble gas can be treated by mechanical agitation and/or heating to desorb the heavy noble gas for analysis and/or containment and allow recycling of the oil to the reservoir.

  5. Fluid clathrate system for continuous removal of heavy noble gases from mixtures of lighter gases

    DOEpatents

    Gross, K.C.; Markun, F.; Zawadzki, M.T.

    1998-04-28

    An apparatus and method are disclosed for separation of heavy noble gas in a gas volume. An apparatus and method have been devised which includes a reservoir containing an oil exhibiting a clathrate effect for heavy noble gases with a reservoir input port and the reservoir is designed to enable the input gas volume to bubble through the oil with the heavy noble gas being absorbed by the oil exhibiting a clathrate effect. The gas having reduced amounts of heavy noble gas is output from the oil reservoir, and the oil having absorbed heavy noble gas can be treated by mechanical agitation and/or heating to desorb the heavy noble gas for analysis and/or containment and allow recycling of the oil to the reservoir. 6 figs.

  6. Ionization and positronium formation in noble gases

    SciTech Connect

    Marler, J.P.; Sullivan, J.P.; Surko, C.M.

    2005-02-01

    Absolute measurements are presented for the positron-impact cross sections for direct ionization and positronium formation of noble gas atoms in the range of energies from threshold to 90 eV. The experiment uses a cold, trap-based positron beam and the technique of studying positron scattering in a strong magnetic field. The current data show generally good, quantitative agreement with previous measurements taken using a qualitatively different method. However, significant differences in the cross sections for both direct ionization and positronium formation are also observed. An analysis is presented that yields another, independent measurement of the direct ionization and positronium formation cross sections that is in agreement with the present, direct measurements to within {+-}10% for argon, krypton, and xenon. Comparison with available theoretical predictions yields good quantitative agreement for direct ionization cross sections, and qualitative agreement in the case of positronium formation.

  7. Seeded optically driven avalanche ionization in molecular and noble gases

    NASA Astrophysics Data System (ADS)

    Polynkin, Pavel; Pasenhow, Bernard; Driscoll, Nicholas; Scheller, Maik; Wright, Ewan M.; Moloney, Jerome V.

    2012-10-01

    We report experimental and numerical results on the dual laser-pulse plasma excitation in molecular and noble gases at atmospheric pressure. Dilute plasma channels generated through filamentation of ultraintense femtosecond laser pulses in air, argon, and helium are densified through the application of multijoule nanosecond heater pulses. Plasma densification in molecular gases is always accompanied by the fragmentation of the plasma channels into discrete bubbles, while in atomic gases, under certain conditions, the densified channels remain smooth and continuous. The densification effect in atomic gases persists through considerably longer delays between the femtosecond and nanosecond pulses compared to that in molecular gases. Using rate equations we trace this difference in the temporal dynamics of densification to the different cooling mechanisms operative in atomic and molecular cases.

  8. Fullerenes: an extraterrestrial carbon carrier phase for noble gases.

    PubMed

    Becker, L; Poreda, R J; Bunch, T E

    2000-03-28

    In this work, we report on the discovery of naturally occurring fullerenes (C60 to C400) in the Allende and Murchison meteorites and some sediment samples from the 65 million-year-old Cretaceous/Tertiary boundary layer (KTB). Unlike the other pure forms of carbon (diamond and graphite), fullerenes are extractable in an organic solvent (e.g., toluene or 1,2,4-trichlorobenzene). The recognition of this unique property led to the detection and isolation of the higher fullerenes in the Kratschmer/Huffmann arc evaporated graphite soot and in the carbon material in the meteorite and impact deposits. By further exploiting the unique ability of the fullerene cage structure to encapsulate and retain noble gases, we have determined that both the Allende and Murchison fullerenes and the KTB fullerenes contain trapped noble gases with ratios that can only be described as extraterrestrial in origin.

  9. Fullerenes: An extraterrestrial carbon carrier phase for noble gases

    PubMed Central

    Becker, Luann; Poreda, Robert J.; Bunch, Ted E.

    2000-01-01

    In this work, we report on the discovery of naturally occurring fullerenes (C60 to C400) in the Allende and Murchison meteorites and some sediment samples from the 65 million-year-old Cretaceous/Tertiary boundary layer (KTB). Unlike the other pure forms of carbon (diamond and graphite), fullerenes are extractable in an organic solvent (e.g., toluene or 1,2,4-trichlorobenzene). The recognition of this unique property led to the detection and isolation of the higher fullerenes in the Kratschmer/Huffmann arc evaporated graphite soot and in the carbon material in the meteorite and impact deposits. By further exploiting the unique ability of the fullerene cage structure to encapsulate and retain noble gases, we have determined that both the Allende and Murchison fullerenes and the KTB fullerenes contain trapped noble gases with ratios that can only be described as extraterrestrial in origin. PMID:10725367

  10. Distribution of solar wind implanted noble gases in lunar samples

    NASA Technical Reports Server (NTRS)

    Kiko, J.; Kirsten, T.

    1986-01-01

    The distribution of solar wind implanted noble gases in lunar samples depends on implantation energy, fluence, diffusion, radiation damage and erosion. It is known that at least the lighter rare gases are fractionated after implantation, but the redistribution processes, which mainly drive the losses, are not well understood. Some information about this one can get by looking at the concentration profiles of solar wind implanted He-4 measured by the Gas Ion Probe in single lunar grains. The observed profiles were divided in three groups. These groups are illustrated and briefly discussed.

  11. Novel MRI Applications of Laser-Polarized Noble Gases

    NASA Astrophysics Data System (ADS)

    Mair, R. W.; Walsworth, R. L.

    2002-04-01

    Gas-phase NMR has great potential as a probe for a variety of interesting physical and biomedical problems that are not amenable to study by water or similar liquid. However, NMR of gases was largely neglected due to the low signal obtained from the thermally-polarized gases with very low sample density. The advent of optical pumping techniques for enhancing the polarization of the noble gases 3He and 129Xe has bought new life to this field, especially in medical imaging where 3He lung inhalation imaging is approaching a clinical application. However, there are numerous applications in materials science that also benefit from the use of these gases. We review primarily non-medical applications of laser-polarized noble gases for both NMR imaging and spectroscopy, and highlight progress with examples from our laboratory including high-resolution imaging at mT applied field strength and velocity imaging of convective flow. Porous media microstucture has been probed with both thermal and laser-polarized xenon, as xenon is an ideal probe due to low surface interaction with the grains of the porous media.

  12. Recent Experimental Advances to Determine (noble) Gases in Waters

    NASA Astrophysics Data System (ADS)

    Kipfer, R.; Brennwald, M. S.; Huxol, S.; Mächler, L.; Maden, C.; Vogel, N.; Tomonaga, Y.

    2013-12-01

    In aquatic systems noble gases, radon, and bio-geochemically conservative transient trace gases (SF6, CFCs) are frequently applied to determine water residence times and to reconstruct past environmental and climatic conditions. Recent experimental breakthroughs now enable ● to apply the well-established concepts of terrestrial noble gas geochemistry in waters to the minute water amounts stored in sediment pore space and in fluid inclusions (A), ● to determine gas exchange processes on the bio-geochemical relevant time scales of minutes - hours (B), and ● to separate diffusive and advective gas transport in soil air (C). A. Noble-gas analysis in water samples (< 1 g) facilitates determining the solute transport in the pore space and identifying the origin of bio- and geogenic fluids in (un) consolidated sediments [1]. Advanced techniques that combine crushing and sieving speleothem samples in ultra-high-vacuum to a specific grain size allow to separate air and water-bearing fluid inclusions and thus enables noble-gas-based reconstruction of environmental conditions from water masses as small as 1mg [2]. B. The coupling of noble gas analysis with approaches of gas chromatography permits combined analysis of noble gases and other gases species (e.g., SF6, CFCs, O2, N2) from a single water sample. The new method substantially improves ground water dating by SF6 and CFCs as excess air is quantified from the same sample and hence can adequately be corrected for [3]. Portable membrane-inlet mass spectrometers enable the quasi-continuous and real-time analysis of noble gases and other dissolved gases directly in the field, allowing, for instance, quantification of O2 turnover rates on small time scales [4]. C. New technical developments perfect 222Rn analysis in water by the synchronous the determination of the short-lived 220Rn. The combined 220,222Rn analysis sheds light on the emanation behaviour of radon by identifying soil water content to be the crucial

  13. Howardite Noble Gases as Indicators of Asteroid Surface Processing

    NASA Technical Reports Server (NTRS)

    Cartwright, J. A.; Mittlefehldt, D. W.; Herrin, J. S.; Ott, U.

    2011-01-01

    The HED (Howardite, Eucrite and Diogenite) group meteorites likely or iginate from the Asteroid 4 Vesta - one of two asteroid targets of NA SA's Dawn mission. Whilst Howardites are polymict breccias of eucriti c and diogenitic material that often contain "regolithic" petrologica l features, neither their exact regolithic nature nor their formation processes are well defined. As the Solar Wind (SW) noble gas compon ent is implanted onto surfaces of solar system bodies, noble gas anal yses of Howardites provides a key indicator of regolithic origin. In addition to SW, previous work by suggested that restricted Ni (300-12 00 micro g/g) and Al2O3 (8-9 wt%) contents may indicate an ancient we ll-mixed regolith. Our research combines petrological, compositional and noble gas analyses to help improve understanding of asteroid reg olith formation processes, which will play an intergral part in the i nterpretation of Dawn mission data. Following compositional and petrological analyses, we developed a regolith grading scheme for our sampl e set of 30 Howardites and polymict Eucrites. In order to test the r egolith indicators suggested by, our 8 selected samples exhibited a r ange of Ni, Al2O3 contents and regolithic grades. Noble gas analyses were performed using furnace stepheating on our MAP 215-50 noble gas mass spectrometer. Of our 8 howardites, only 3 showed evidence of SW noble gases (e.g approaching Ne-20/Ne-22 approximately equals 13.75, Ne-21/Ne-22 approximately equals 0.033). As these samples display low regolithic grades and a range of Ni and Al2O3 contents, so far we are unable to find any correlation between these indicators and "regolit hic" origin. These results have a number of implications for both Ho wardite and Vesta formation, and may suggest complex surface stratigr aphies and surface-gardening processes.

  14. Noble gases, K, U, Th, and Pb in native gold

    NASA Astrophysics Data System (ADS)

    Engster, O.; Niedermann, S.; Thalmann, C.; Frei, R.; Kramers, J.; KräHenbühl, U.; Liu, Y. Z.; Hofmann, B.; Boer, R. H.; Reimold, W. U.; Bruno, L.

    1995-12-01

    We present determinations of the noble gas and Pb isotopic abundances and of K, Th, and U concentrations of native gold. Our results demonstrate that gold is an excellent carrier for crustal volatiles, but direct dating of gold using the U, Th-4He, 40K-40Ar, and U fission Xe methods was not successful for various reasons. The main significance of this work is the great sensitivity of gold for trapped gases as well as for gases that were produced in situ which gives the prospects of using gold and its fluid and solid inclusions for the study of paleogas composition. Numerous nuclear effects characterize the noble gas inventory of placer gold from Switzerland and Italy, vein gold from Italy, South Africa, and Venezuela, and lode gold from South Africa. The degassing patterns obtained by mass spectrometry show a low-temperature release of volatiles around 500°C from fluid inclusions mainly in vein gold and a high-temperature release from solid inclusions and the gold itself. The low-temperature volatiles represent species that were trapped when the gold crystallized. We investigated the following trapped species: the isotopes of He, Ne, Ar, Kr, Xe, and Pb, and the abundances of K, U, Th, H2O, and CO2. The crustal gases trapped by gold comprise 3He from 6Li(n,α)3H → β- → 3He, 4He and 40Ar from the U, Th, and K decay, and Xe from 238U fission. We observe 4He/40Ar = 3.9 for the radiogenic trapped gases of tertiary gold and a ratio of 1.4 for Archean gold. These ratios are consistent with the production ratios from U and K at the respective times and demonstrate that gold can be used as a sampler of ancient atmospheric gases. The concentrations of U and Th range from a few parts per billion to a few parts per million, and those of K and Pb range up to some tens of parts per million. The antiquity of trapped Pb is indicated by the Pb-Pb model age of about 3000 Ma for the lead extracted from vein gold and quartz of the Lily gold mine (South Africa). Gold also

  15. Effect of Noble Gases on Sonoluminescence Temperatures during Multibubble Cavitation

    SciTech Connect

    Didenko, Yuri T.; McNamara, William B. III; Suslick, Kenneth S.

    2000-01-24

    Sonoluminescence spectra were collected from Cr(CO){sub 6} solutions in octanol and dodecane saturated with various noble gases. The emission from excited-state metal atoms serves as an internal thermometer of cavitation. The intensity and temperature of sonoluminescence increases from He to Xe. The intensity of the underlying continuum, however, grows faster with increasing temperature than the line emission. Dissociation of solvent molecules within the bubble consumes a significant fraction of the energy generated by the collapsing bubble, which can limit the final temperature inside the bubble. (c) 2000 The American Physical Society.

  16. Effective Giromagnetic Ratios in Artifical Nuclear Magnetization Pumping of the Noble Gases Mix

    NASA Astrophysics Data System (ADS)

    Popov, E. N.; Barantsev, K. A.; Litvinov, A. N.

    2015-09-01

    Dynamic of the nuclear magnetization of the two noble gases mix was studied in this research. Nuclear magnetization pumped along the induction of external magnetic field. Vector of nuclear magnetization is given a tilt by the week rotational magnetic field, which makes NMR for noble gases. Interaction between the nuclear magnetic moments of the different noble gases adducted to shifts at the frequency of nuclear moments precession in external magnetic field. Effective gyromagnetic ratios of the nuclear of noble gases is defined and it different from the tabulated value. There is theoretical calculation of effective gyromagnetic ratios in this research.

  17. Solubilities of nitrogen and noble gases in basalt melt

    NASA Technical Reports Server (NTRS)

    Miyazaki, A.; Hiyagon, H.; Sugiura, N.

    1994-01-01

    Nitrogen and noble gases are important tracers in geochemistry and chosmochemistry. Compared to noble gases, however, physicochemical properties of nitrogen, such as solubility in melt or melt/silicate partition, are not well known. Solubility of nitrogen in basalt melt depends on redox condition of the atmosphere. For example, solubility of nitrogen in E chondrite melt under reducing conditions is as high as 2 mol percent at 1500 C, suggesting that nitrogen is chemically dissolved in silicate melts, i.e., being dissolved as free anions or replacing oxygen sites in silicate network. However, the solubility and the dissolution mechanism of nitrogen under oxidizing conditions are not well investigated. To obtain nitrogen solubility in silicate melts under various redox conditions and to understand its mechanism, we are conducting experiments by using (15)N(15)N-labeled nitrogen gas. This makes it easy to distinguish dissolved nitrogen from later contamination of atmospheric nitrogen, and hence enables us to measure the nitrogen solubility accurately. As a preliminary experiment, we have measured solubility of nitrogen in basalt melt under the atmospheric oxygen pressure.

  18. Solubilities of noble gases in magnetite - Implications for planetary gases in meteorites.

    NASA Technical Reports Server (NTRS)

    Lancet, M. S.; Anders, E.

    1973-01-01

    Solubilities of noble gases in magnetite were determined by growing magnetite in a noble-gas atmosphere between 450 and 700 K. Henry's law is obeyed at pressures up to .01 atm for He, Ne, Ar and up to .00001 atm for Kr, Xe, with the following distribution coefficients at 500 K: He 0.042, Ne 0.016, Ar 3.6, Kr 1.3, Xe 0.88, some 100 to 100,000 times higher than previous determinations on silicate and fluoride melts. Apparent heats of solution are in sharp contrast with earlier determinations on melts which were small and positive, but are comparable to the values for clathrates. Presumably the gases are held in anion vacancies.

  19. Exploring the Effects on Lipid Bilayer Induced by Noble Gases via Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Chen, Junlang; Chen, Liang; Wang, Yu; Wang, Xiaogang; Zeng, Songwei

    2015-11-01

    Noble gases seem to have no significant effect on the anesthetic targets due to their simple, spherical shape. However, xenon has strong narcotic efficacy and can be used clinically, while other noble gases cannot. The mechanism remains unclear. Here, we performed molecular dynamics simulations on phospholipid bilayers with four kinds of noble gases to elucidate the difference of their effects on the membrane. Our results showed that the sequence of effects on membrane exerted by noble gases from weak to strong was Ne, Ar, Kr and Xe, the same order as their relative narcotic potencies as well as their lipid/water partition percentages. Compared with the other three kinds of noble gases, more xenon molecules were distributed between the lipid tails and headgroups, resulting in membrane’s lateral expansion and lipid tail disorder. It may contribute to xenon’s strong anesthetic potency. The results are well consistent with the membrane mediated mechanism of general anesthesia.

  20. Chemical composition of Titan's lakes and noble gases sequestration

    NASA Astrophysics Data System (ADS)

    Cordier, D.; Mousis, O.; Lunine, J.-I.; Lavvas, P.; Lobo, L.; Ferreira, A.

    2010-04-01

    Titan is one of the most enigmatic objects in the Solar System. The presence of hydrocarbon lakes and even a global ocean have been suspected for decades. The dark features discovered by the CASSINI spacecraft are good candidates for these expected lakes (see McEwen et al. 2005 and Stofan et al. 2007). Their chemical composition has still not been measured but numerical models can give relatively accurate predictions. In the present work, we use the recent model of Titan's lakes chemical composition elaborated by Cordier et al. (2009) in light of the recent Cassini-Huygens measurements in order to investigate the possibility of sequestration of large quantities of noble gases in these liquids. Indeed, the noble gas abundances have been found to be largely in subsolar abundances in the atmosphere of Titan and the origin of this impoverishment is still poorly understood. Our preliminary results show that, under specific circumstances, at least the atmospheric depletion in krypton could be caused by its dissolution in the Titan's surface hydrocarbon liquid phase.

  1. Shock Reflection in a Binary Mixture of Noble Gases

    NASA Astrophysics Data System (ADS)

    Whitlock, S. T.; Baganoff, D.

    1996-11-01

    The standard implementation of Bird's Direct Simulation Monte Carlo (DSMC) method for the simulation of multiple-specie flows uses single-specie transport data as input to an ad hoc combining formula to define parameters used in binary collisions between non-like species. To ascertain the suitability of this approach, we focus on the details of translational nonequilibrium in the flow of a binary mixture of noble gases. Existing experimental results for the one-dimensional reflection of a shock wave in a mixture of helium (He) and xenon (Xe) yield a standard of comparison. The molecular weight and diameter of He:Xe are sufficiently disparate so that the relevant time scales of the reflection process are distinct. Simulations are performed on the Intel Paragon using an adaptation of the DSMC method suitable for the parallel computing environment. Using the best characterizations of noble gas intermolecular potentials that have been published to date, we are able to produce simulations of the reflection process which compare favorably with experiment over a range of Xe concentrations. Investigations of various combining rules to arrive at non-like specie collision parameters indicate that any reasonable combining rule works provided that the single-specie data is physically realistic.

  2. Noble gases in the howardites Bholghati and Kapoeta

    NASA Technical Reports Server (NTRS)

    Swindle, T. D.; Hohenberg, C. M.; Nickols, R. H.; Olinger, C.; Garrison, D. H.; Goswami, J. N.

    1990-01-01

    Analyses of noble gases in whole rock samples of the howardites Bholghati and Kapoeta and grain-size separates of Kapoeta yield evidence for excesses of the Xe isotopes Xe-129 , Xe-131, Xe-132, Xe-134, and Xe-136 in a low-temperture component, similar to lunar excess fission Xe. Such a component may be able to provide chronometric information if the relative abundances of radioactive progenitors (I-129, Pu-244, and U-238) can be determined, but the isotopic spectra obtained are not sufficiently precise to do so. Eucritic clast BH-5 in Bholghati contains Xe produced in situ by the decay of Pu-244. Calculated fission Xe retention ages are 30-70 Ma after the formation of the solar system, consistent with the apparent presence of Sm-146 decay products. Both the clast and the matrix of Bholghati have K-Ar ages of about 2 Ga, suggesting a common thermal event at least that recently.

  3. Noble gases and cosmogenic radionuclides in the Eltanin Pacific meteorite

    SciTech Connect

    Bogard, D D; Garrison, D H; Caffee, M W; Kyte, F; Nishiizumi, K

    2000-01-14

    A 1.5 cm long, 1.2 g specimen of the Eltanin meteorite was found at 10.97 m depth in Polarstern piston core PS2704-1. The early studies indicated that the small fragments of the Eltanin meteorite was debris from a km-sized asteroid which impacted into the deep-ocean basin. In this study, the authors measured {sup 39}Ar-{sup 40}Ar age, noble gases, and cosmogenic radionuclides in splits of specimen as a part of consortium studies of Eltanin meteorite. They concluded that the specimen was about 3 m deep from the asteroid surface. The exposure age of the Eltanin asteroid was about 20 Myr.

  4. Solar Noble Gases from ACFER 111 Metal Etched in Vacuo

    NASA Astrophysics Data System (ADS)

    Pedroni, A.; Begemann, F.

    1992-07-01

    Regolith grains dissolved by stepwise etching release a mixture of near-surface implanted Solar Wind gases (SW) and a deeper- sited, isotopically heavier component attributed to Solar Energetic Particles (SEP) (1,2,3). In all regolith materials examined so far the elemental abundance ratios in both components are distinctly different from the canonical solar values (4). The differences are generally explained to be owing to diffusive elemental fractionation although there is no strong evidence that upon their implantation the composition of the gases was indeed solar. In contrast, the solar noble gases present in the H3-H6 chondritic regolith breccia Acfer 111 appear to be nearly unfractionated and thus offer a unique chance for more accurate analyses. A magnetic fraction of Acfer 111 matrix, consisting of approx. 80% metal and 20% silicates, was etched with a 60 g/mol aqueous solution of HNO3 in a high-vacuum extraction line similar to that in (1). The gases released were drawn off in steps and analyzed; the experiment was stopped when ~97% of the metal and ~50% of the silicates were dissolved. As etching proceeds, the isotopic composition of the released gases changes in a pattern similar to that observed previously in other regolithic materials. The isotopic composition of solar neon decreases from ^20Ne/^22Ne=13.1 in the first step to ^20Ne/^22Ne=11.6, which can be interpreted as a change of the mixing ratio of SW (^20Ne/^22Ne=13.7) and SEP (^20Ne/^22Ne=11.3) neon. The isotopic compositions of solar He, Ar, and Kr are consistent with their also being mixtures of SW and SEP having compositions reported previously (2,3), although our data are compromised to some extent by the presence of planetary gases extracted from the silicates and, in the first steps, by atmospheric contamination probably present in terrestrial weathering products (mostly rust). The elemental composition of noble gases released from Acfer 111 was distinct from previous experiments: The (^4He

  5. Solar Noble Gases in Polymict Ureilites and an Update on Ureilite Noble Gas Data

    NASA Astrophysics Data System (ADS)

    Ott, U.; Lohr, H. P.; Begemann, F.

    1993-07-01

    Ureilites are one of the least understood classes of meteorites; they show signs of being processed, but also appear to be primitive, with abundant carbon and trapped noble gases [1-6]. We have now begun to analyze a number of recently recovered specimens: one from the Saharan desert (Acfer 277) amd five from the Antarctic (LEW 85328, LEW 85440, EET 87720, FRO 90036, and FRO 90054). Analyses of Acfer 277, LEW 85328, and EET 87720 are complete (Table 1). Solar noble gases are present in polymict EET 87720, as shown by the three- isotope plot of Fig. 1. There, in contrast to the bulk data point for Acfer 277, data points for EET 87720 deviate from a mixing line between "typical" spallation Ne (as approximated here by the spallation-dominated 1800 degrees C step for EET 87720) and Ne-U [7] toward higher ^20Ne/^22Ne. A line fitted to the EET 87720 data points passes slightly below Ne-B [8]. The situation is similar for sample F1 from polymict EET 83309 [9], which is shown for comparison. Additional support for the presence of solar gases arises from the abundance of ^4He (~9 x 10^-5 cm^3 STP/g in EET 87720-F1, corrected for spallogenic contributions), which in both cases is far higher than in other ureilite bulk samples [6,10]. Also, in the ratio of spallation-corrected ^4He to trapped ^36Ar, these two polymict ureilites clearly stand out. Helium-4/argon-36 ratios in EET 87720-F1 and EET 83309-F1 are ~20 and ~28 respectively, at least 1 order of magnitude higher than in bulk monomict ureilites and 2 orders of magnitude higher than what appears typical of ureilite diamonds [6]. Nilpena, another polymict ureilite [11], also has a ^4He/^36Ar ratio (2.1 in Nilpena II-1 [7]) higher than all monomict ureilites but one (Dingo Pup Donga), indicating the presence of solar noble gases (in variable contents) as a possible general feature of polymict ureilites, similar to the presence in them of nitrogen with high delta(^15N/^14N) [12]. Monomict LEW 85328 has a very high (^22Ne

  6. The fractionation of noble gases in diamonds of CV3 Efremovka chondrite

    NASA Technical Reports Server (NTRS)

    Fisenko, A. V.; Verchovsky, A. B.; Semjonova, L. F.; Shukolyukov, Yu. A.

    1993-01-01

    It was shown that in diamonds of Efremovka CV3 the noble gases with normal isotopic compositions are fractionated in different degree while the correlation of isotopic anomalous components is nearly constant. Some data for noble gases in DE-4 sample of Efremovka chondrite are considered. In contrast to DE-2 sample the DE-4 was treated except conc. HClO4, 220 C in addition with mixture of conc. H2SO4+H3PO4 (1:1), 220 C, twice. Noble gases analysis were performed in Germany at Max Plank Institute fur Chemie. Noble gases were released by oxidation of samples at stepped heating from 420 C to 810 C and by pyrolysis at 580, 590, and 680 C.

  7. Review: gas-phase ion chemistry of the noble gases: recent advances and future perspectives.

    PubMed

    Grandinetti, Felice

    2011-01-01

    This review article surveys recent experimental and theoretical advances in the gas-phase ion chemistry of the noble gases. Covered issues include the interaction of the noble gases with metal and non-metal cations, the conceivable existence of covalent noble-gas anions, the occurrence of ion-molecule reactions involving singly-charged xenon cations, and the occurrence of bond-forming reactions involving doubly-charged cations. Research themes are also highlighted, that are expected to attract further interest in the future.

  8. Biomedical Magnetic Resonance Imaging and Spectroscopy with Laser Polarized Noble Gases

    NASA Astrophysics Data System (ADS)

    Welsh, R. C.; Rosen, M. S.; Coulter, K. P.; Chupp, T. E.; Swanson, S. D.; Agranoff, B. W.; Prince, M. R.

    1996-05-01

    In the past year, a great deal of attention has been drawn to the use of laser polarized noble gases to produce magnetic resonance images of rodent and human lungs. Initial demonstrations proved the principle that air space images can be produced with noble gases polarized to several percent. (The noble gas density is thousands of times smaller, but the noble gas polarization is thousands of times greater than the proton polarization of order 10-5 at 2 Tesla.) The manifold motivations include improvement of pulmonary and circulatory diagnostic radiology techniques as well as study of physiological function including neurological response. We have undertaken a program of development and application of MR imaging and spectroscopy using laser polarized gases with several goals including development of techniques and technologies to facilitate research and eventual medical applications. This talk will describe this multi-disciplinary program combining laser and optical physics, magnetic resonance tomography, neurophysiology and medical science.

  9. Heavily fractionated noble gases in an acid residue from the Klein Glacier 98300 EH3 chondrite

    NASA Astrophysics Data System (ADS)

    Nakashima, Daisuke; Ott, Ulrich; El Goresy, Ahmed; Nakamura, Tomoki

    2010-09-01

    Noble gases were measured both in bulk samples (stepped pyrolysis and total extraction) and in a HF/HCl residue (stepped pyrolysis and combustion) from the Klein Glacier (KLE) 98300 EH3 chondrite. Like the bulk meteorite and as seen in previous studies of bulk type 3 E chondrites ("sub-Q"), the acid residue contains elementally fractionated primordial noble gases. As we show here, isotopically these are like those in phase-Q of primitive meteorites, but elementally they are heavily fractionated relative to these. The observed noble gases are different from "normal" Q noble gases also with respect to release patterns, which are similar to those of Ar-rich noble gases in anhydrous carbonaceous chondrites and unequilibrated ordinary chondrites (with also similar isotopic compositions). While we cannot completely rule out a role for parent body processes such as thermal and shock metamorphism (including a later thermal event) in creating the fractionated elemental compositions, parent body processes in general seem not be able to account for the distinct release patterns from those of normal Q noble gases. The fractionated gases may have originated from ion implantation from a nebular plasma as has been suggested for other types of primordial noble gases, including Q, Ar-rich, and ureilite noble gases. With solar starting composition, the corresponding effective electron temperature is about 5000 K. This is lower than inferred for other primordial noble gases (10,000-6000 K). Thus, if ion implantation from a solar composition reservoir was a common process for the acquisition of primordial gas, electron temperatures in the early solar system must have varied spatially or temporally between 10,000 and 5000 K. Neon and xenon isotopic ratios of the residue suggest the presence of presolar silicon carbide and diamond in abundances lower than in the Qingzhen EH3 and Indarch EH4 chondrites. Parent body processes including thermal and shock metamorphism and a late thermal

  10. The noble gases: how their electronegativity and hardness determines their chemistry.

    PubMed

    Furtado, Jonathan; De Proft, Frank; Geerlings, Paul

    2015-02-26

    The establishment of an internally consistent scale of noble gas electronegativities is a long-standing problem. In the present study, the problem is attacked via the Mulliken definition, which in recent years gained widespread use to its natural appearance in the context of conceptual density functional theory. Basic ingredients of this scale are the electron affinity and the ionization potential. Whereas the latter can be computed routinely, the instability of the anion makes the judicious choice of computational technique for evaluating electron affinities much more tricky. We opted for Puiatti's approach, extrapolating the energy of high ε solvent stabilized anions to the ε = 1 (gas phase) case. The results give negative electron affinity values, monotonically increasing (except for helium which is an outlier in most of the story) to almost zero at eka-radon in agreement with high level calculations. The stability of the B3LYP results is successfully tested both via improving the level of theory (CCSD(T)) and expanding the basis set. Combined with the ionization energies (in good agreement with experiment), an electronegativity scale is obtained displaying (1) a monotonic decrease of χ when going down the periodic table, (2) top values not for the noble gases but for the halogens, as opposed to most (extrapolation) procedures of existing scales, invariably placing the noble gases on top, and (3) noble gases having electronegativities close to the chalcogens. In the accompanying hardness scale (hardly, if ever, discussed in the literature) the noble gases turn out to be by far the farthest the hardest elements, again with a continuous decrease with increasing Z. Combining χ value of the halogens and the noble gases the Ng(δ+)F(δ-) bond polarity emerging from ab initio calculations naturally emerges. In conclusion, the chemistry of the noble gases is for a large part determined by their extreme hardness, equivalent to a high resistance to change in its

  11. Method and apparatus for measuring purity of noble gases

    SciTech Connect

    Austin, Robert

    2008-04-01

    A device for detecting impurities in a noble gas includes a detection chamber and a source of pulsed ultraviolet light. The pulse of the ultraviolet light is transferred into the detection chamber and onto a photocathode, thereby emitting a cloud of free electrons into the noble gas within the detection chamber. The cloud of electrons is attracted to the opposite end of the detection chamber by a high positive voltage potential at that end and focused onto a sensing anode. If there are impurities in the noble gas, some or all of the electrons within the cloud will bond with the impurity molecules and not reach the sensing anode. Therefore, measuring a lower signal at the sensing anode indicates a higher level of impurities while sensing a higher signal indicates fewer impurities. Impurities in the range of one part per billion can be measured by this device.

  12. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico

    USGS Publications Warehouse

    Mazor, E.; Truesdell, A.H.

    1984-01-01

    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He and 40Ar) and atmospheric noble gases (Ne, Ar and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water that penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic He and 40Ar formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 - 30%) and mixing with shallow cold water occurred (0 - 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 - 3% steam separation and complement other tracers, such as C1 or temperature, which are effective only beyond this range. ?? 1984.

  13. Biomedical magnetic resonance imaging and spectroscopy with laser polarized noble gases

    SciTech Connect

    Welsh, R.C.; Rosen, M.S.; Coulter, K.P.; Chupp, T.E.; Swanson, S.D.; Agranoff, B.W.; Prince, M.R.

    1996-05-01

    In the past year, a great deal of attention has been drawn to the use of laser polarized noble gases to produce magnetic resonance images of rodent and human lungs. Initial demonstrations proved the principle that air space images can be produced with noble gases polarized to several percent. (The noble gas density is thousands of times greater than the proton polarization of order 10{sup {minus}5} at 2 Tesla.) The manifold motivations include improvement of pulmonary and circulatory diagnostic radiology techniques as well as study of physiological function including neurological response. The authors have undertaken a program of development and application of MR imaging and spectroscopy using laser polarized gases with several goals including development of techniques and technologies to facilitate research and eventual medical applications. This talk will describe this multi-disciplinary program combining laser and optical physics, magnetic resonance tomography, neurophysiology and medical science.

  14. Dynamics of a geothermal field traced by noble gases: Cerro Prieto, Mexico

    SciTech Connect

    Mazor, E.; Truesdell, A.H.

    1981-01-01

    Noble gases have been measured mass spectrometrically in samples collected during 1977 from producing wells at Cerro Prieto. Positive correlations between concentrations of radiogenic (He, /sup 40/Ar) and atmospheric noble gases (Ne, Ar, and Kr) suggest the following dynamic model: the geothermal fluids originated from meteoric water penetrated to more than 2500 m depth (below the level of first boiling) and mixed with radiogenic helium and argon-40 formed in the aquifer rocks. Subsequently, small amounts of steam were lost by a Raleigh process (0 to 3%) and mixing with shallow cold water occurred (0 to 30%). Noble gases are sensitive tracers of boiling in the initial stages of 0 to 3% steam separation and complement other tracers, such as Cl or temperature, which are effective only beyond this range.

  15. On the origin of noble gases in mantle plumes.

    PubMed

    Coltice, Nicolas; Ricard, Yanick

    2002-11-15

    The chemical differences between deep- and shallow-mantle sources of oceanic basalts provide evidence that several distinct components coexist within the Earth's mantle. Most of these components have been identified as recycled in origin. However, the noble-gas signature is still a matter of debate and questions the preservation of primitive regions in the convective mantle. We show that a model where the noble-gas signature observed in Hawaii and Iceland comes from a pristine homogeneous deep layer would imply a primitive (3)He content and (3)He/(22)Ne ratio that are very unlikely. On the contrary, mass balances show that the partly degassed peridotite of a marble-cake mantle can be the noble-gas end-member with an apparent 'primitive'-like composition. This component is mixed with recycled oceanic crust in different proportions in the plume sources and in the shallow mantle. A recycling model of the mantle, involving gravitational segregation of the oceanic crust at the bottom of the mantle, potentially satisfies trace-element as well as noble-gas constraints.

  16. Elemental and isotopic compositions of noble gases in the mantle: Pete's path

    NASA Astrophysics Data System (ADS)

    Moreira, Manuel; Péron, Sandrine; Colin, Aurélia

    2016-04-01

    Noble gases are tracers of the origin of the volatiles on Earth and other terrestrial planets. The determination of their isotopic compositions in oceanic basalts allows discriminating between different possible scenarios for the origin of volatiles (chondritic, solar, cometary). However, oceanic basalts show a ubiquitous component having atmospheric noble gas compositions, which reflects a shallow air contamination. This component masks the mantle composition and only step crushing is able to (partially) remove it. Nevertheless, the exact mantle composition is always unconstrained due to the uncertainty on its complete removal. Developed by Pete Burnard (Burnard et al., 1997; Burnard, 1999), single vesicle analysis using laser ablation is a challenging technique to determine the mantle composition, free of atmospheric contamination. We have used this technique to measure He, Ne, Ar isotopes and CO2 in single vesicles from both MORB and OIB (Galapagos, Iceland). Vesicles are located using microtomography and the noble gases are measured using the Noblesse mass spectrometer from IPGP using an Excimer laser to open the vesicles. Both Galapagos and Iceland samples show that the 20Ne/22Ne ratio is limited to ~12.8 in the primitive mantle, suggesting that the origin of the light noble gases can be attributed to irradiated material instead of a simple dissolution of solar gases into a magma ocean (Moreira and Charnoz, 2016). Such a scenario of incorporation of light noble gases by irradiation also explains the terrestrial argon isotopic composition. However, the Kr and Xe contribution of implanted solar wind is small and these two noble gases were carried on Earth by chondrites and/or cometary material. Burnard, P., D. Graham and G. Turner (1997). "Vesicle-specific noble gas analyses of « popping rock »: implications for primordial noble gases in the Earth." Science 276: 568-571. Burnard, P. (1999). "The bubble-by-bubble volatile evolution of two mid-ocean ridge

  17. Stellar condensates in meteorites - Isotopic evidence from noble gases

    NASA Technical Reports Server (NTRS)

    Lewis, R. S.; Alaerts, L.; Matsuda, J.-I.; Anders, E.

    1979-01-01

    The Murchison carbonaceous chondrite contains three isotopically anomalous noble-gas components of apparently presolar origin: two kinds of Ne-E, (Ne-20)/(Ne-22) less than 0.6, and s-process Kr + Xe (enriched in the even isotopes 82, 84, 86, 128, 130, 132). Their carriers are tentatively identified as spinel and two carbonaceous phases, the principal high-temperature stellar condensates at low and high C/O ratios, respectively.

  18. Methane activation using noble gases in a dielectric barrier discharge reactor

    SciTech Connect

    Jo, Sungkwon; Hoon Lee, Dae; Seok Kang, Woo; Song, Young-Hoon

    2013-08-15

    The conversion of methane is measured in a planar-type dielectric barrier discharge reactor using three different noble gases—He, Ne, and Ar—as additives. The empirical results obtained clearly indicate that methane activation is considerably affected by thy type of noble gas used. Through 0-D calculations, the discharge parameters inside the reactor, i.e., electron temperature and electron density, are estimated using experiment results. A comparison of the discharge characteristics and experimental results shows that the electron temperature is an important factor in achieving high methane activation and the mixture with Ar gas shows the highest methane conversion. These results are constructed using the mechanisms of energy and charge transfer from excited and ionized noble gas atoms to methane molecules, considering the number density of active atoms of noble gases. Finally, electron temperatures obtained for gas mixtures having different reactant compositions and concentrations are analyzed to estimate methane activation.

  19. REMOVAL OF TITAN'S ATMOSPHERIC NOBLE GASES BY THEIR SEQUESTRATION IN SURFACE CLATHRATES

    SciTech Connect

    Mousis, Olivier; Picaud, Sylvain; Cordier, Daniel; Mandt, Kathleen E.; Hunter Waite, J. Jr.

    2011-10-10

    A striking feature of the atmosphere of Titan is that no heavy noble gases other than argon were detected by the Gas Chromatograph Mass Spectrometer aboard the Huygens probe during its descent to Titan's surface in 2005 January. Here we provide an explanation of the mysterious absence or rarity of these noble gases in Titan's atmosphere: the thermodynamic conditions prevailing at the surface-atmosphere interface of the satellite allow the formation of multiple guest clathrates that preferentially store some species, including all heavy noble gases, over others. The clean water ice needed for the formation of these clathrates could be delivered by successive episodes of cryovolcanic lavas that have been hypothesized to regularly cover the surface of Titan. The formation of clathrates in the porous lavas and their propensity for trapping Ar, Kr, and Xe would progressively remove these species from the atmosphere of Titan over the course of its history. In some circumstances, a global clathrate crust with an average thickness not exceeding a few meters could be sufficient on Titan for a complete removal of the heavy noble gases from the atmosphere.

  20. Noble Gases in Nakhla and Three Nakhlites Miller Range 090030, 090032, and 090136

    NASA Astrophysics Data System (ADS)

    Nagao, K.; Haba, M. K.; Park, J.; Choi, J.; Baek, J. M.; Park, C.; Lee, J. I.; Lee, M. J.; Mikouchi, T.; Nyquist, L. E.; Herzog, G. F.; Turrin, B. D.; Lindsay, F. N.; Delaney, J. S.; Swisher, C. C., III

    2016-08-01

    Noble gas compositions of the Miller Range nakhlites release Kr and Xe with low 84Kr/132Xe of ≤1 and high 129Xe/132Xe of 1.95-2.13 at low heating temperature (300-400°C). The gases would be heavily fractionated martian atmosphere trapped in aqueously altered materials.

  1. Noble gases and the early history of the Earth: Inappropriate paradigms and assumptions inhibit research and communication

    NASA Technical Reports Server (NTRS)

    Huss, G. R.; Alexander, E. C., Jr.

    1985-01-01

    The development of models as tracers of nobel gases through the Earth's evolution is discussed. A new set of paradigms embodying present knowledge was developed. Several important areas for future research are: (1) measurement of the elemental and isotopic compositions of the five noble gases in a large number of terrestrial materials, thus better defining the composition and distribution of terrestrial noble gases; (2) determinations of relative diffusive behavior, chemical behavior, and the distribution between solid and melt of noble gases under mantle conditions are urgently needed; (3) disequilibrium behavior in the nebula needs investigation, and the behavior of plasmas and possible cryotrapping on cold nebular solids are considered.

  2. Shock waves in noble gases and their mixtures

    NASA Astrophysics Data System (ADS)

    Bratos, M.; Herczynski, R.

    The shock wave structures in pure monatomic gases and in binary gas mixtures are investigated in this paper using a variational approach. The idea of Mott-Smith's distribution function (generalized in the case of a gas mixture) was combined with Tamm's method of solving the Boltzmann equation. The intermolecular potential used is of the Lennard-Jones type. The relation between the dimensionless shock wave thickness and Mach number in front of the shock wave is analyzed. Special attention was paid to the determination of shock wave structures in mixtures of gases with disparate molecular masses. The calculation performed for the shock wave in the binary gas mixture, xenon-helium, confirm the existence of a 'hump' of the density profile of the lighter component. The heavy gas component temperature overshoots its downstream equilibrium value in the case of a mixture of gases with disparate molecular masses and for a small mole fraction of the heavy gas component.

  3. The record of cosmogenic, radiogenic, fissiogenic, and trapped noble gases in recently recovered Chinese and other chondrites

    NASA Astrophysics Data System (ADS)

    Eugster, O.; Michel, Th.; Niedermann, S.; Wang, D.; Yi, W.

    1993-03-01

    Noble-gas isotopic abundances were determined in 36 recently recovered chondrites including 27 chondrites recovered in China. The comparison of the release patterns of trapped noble gases from ordinary and from carbonaceous chondrites showed that the planetary trapped noble gases in ordinary chondrites were released mainly above 1200 C, whereas more than 85 percent of noble gases trapped in carbonaceous chondrites were released at or below 1200 C, indicating that the carrier phases of the trapped noble gases in ordinary and in carbonaceous chondrites may not be the same. It is suggested that the ordinary chondrites started to retain fission Xe about 48 +/- 30 Ma earlier than Angra dos Reis. No systematic differences were observed between H, L, and LL or type 5 and 6 chondrites with respect to the time of fission Xe retention. Eight chondrites displayed neutron capture effects due to secondary cosmic-ray-produced neutrons.

  4. Low field magnetic resonance imaging of laser-polarized noble gases

    NASA Astrophysics Data System (ADS)

    Wong, G. P.; Tseng, C.-H.; Mair, R. W.; Hoffmann, D.; Walsworth, R. L.; Pomeroy, V. R.; Hersman, F. W.; Cory, D. G.

    1998-05-01

    We have demonstrated low field magnetic resonance imaging (MRI) using laser-polarized noble gases. Conventional MRI requires large magnetic fields ( ~ 1 tesla) to create an observable nuclear magnetization via thermal polarization of the nuclear spins (e.g. ^1H spins in water). Alternatively, optical pumping techniques using lasers can create large nuclear spin polarizations (> 10%) in the spin-1/2 noble gases, ^3He and ^129Xe. This laser polarization technique greatly enhances the nuclear magnetic resonance (NMR) detection sensitivity of the noble gases, enabling fast, gas-phase MRI at low magnetic fields (< 100 gauss). Using a simple, wire-wound solenoid, we made images at 21 gauss of laser-polarized ^3He in a variety of samples. Each image took approximately 15 seconds to acquire, with a typical resolution of 1 mm^2. In contrast, a water (^1H) image at the same field with comparable resolution would require ~ 2 months of signal averaging. We also made images that demonstrate the efficacy of low field noble gas MRI for materials that are problematic at high magnetic fields: (i) paramagnetic materials, whose magnetic susceptibilities induce image-distorting field gradients; and (ii) conductors, which prevent high field imaging because of Faraday (i.e. RF) shielding.

  5. Elastic Properties of Films of Water and Noble Gases Condensed at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Pohl, Robert O.

    2003-01-01

    We have shown that there are extensive similarities between the quench-condensed noble gas films and those of amorphous water ice. In particular, both can be quite soft upon deposition and can stiffen considerably when annealed. Furthermore, this stiffening follows a logarithmic time dependence for all substances. The temperature dependence of these behaviors scales with the triple point. The results shown here show a strong thickness dependence, which has implications for any study of mechanical properties of films on substrates. The temperature dependence of the stiffening and the stiffening rate have now been characterized for the noble gases, and these observations provide a roadmap for new experiments on amorphous water ice.

  6. Noble gases in twenty Yamato H-chondrites: Comparison with Allan Hills chondrites and modern falls

    NASA Technical Reports Server (NTRS)

    Loeken, TH.; Scherer, P.; Schultz, L.

    1993-01-01

    Concentration and isotopic composition of noble gases have been measured in 20 H-chrondrites found on the Yamato Mountains ice fields in Antarctica. The distribution of exposure ages as well as of radiogenic He-4 contents is similar to that of H-chrondrites collected at the Allan Hills site. Furthermore, a comparison of the noble gas record of Antarctic H-chrondrites and finds or falls from non-Antarctic areas gives no support to the suggestion that Antarctic H-chrondrites and modern falls derive from differing interplanetary meteorite populations.

  7. Dynamics of strong-field laser-induced microplasma formation in noble gases

    SciTech Connect

    Romanov, D. A.; Compton, R.; Filin, A.; Levis, R. J.

    2010-03-15

    The ultrafast dynamics of microplasmas generated by femtosecond laser pulses in noble gases has been investigated using four-wave mixing (FWM). The time dependence of the FWM signal is observed to reach higher intensity levels faster for Xe, with progressively lower scattering intensity and longer time dynamics for the noble gas series Xe, Kr, Ar, Ne, and He. The temporal dynamics is interpreted in terms of a tunnel ionization and impact cooling mechanism. A formalism to interpret the observed phenomena is presented here with comparison to the measured laser intensity and gas pressure trends.

  8. More on noble gases in Yellowstone National Park hot waters

    USGS Publications Warehouse

    Mazor, E.; Fournier, R.O.

    1973-01-01

    Water and gas samples from research wells in hydrothermal areas of Yellowstone National Park, U.S.A., have been mass spectrometrically analyzed for their rare gas contents and isotopic composition. In agreement with previous findings, the rare gases have been found to originate from infiltrating run-off water, saturated with air at 10 to 20??C. The atmospheric rare gas retention values found for the water varied between 3 and 87 per cent. The fine structure of the Ar, Kr and Xe abundance pattern in the water reveals fraotionational enrichment of the heavier gases due to partial outgassing of the waters. Radiogenic He and Ar have been detected. No positive evidence for magmatic water contribution has been found. Nevertheless, additions of magmatic waters free of rare gas can not be excluded, but if present the proportion is significantly less than 13 to 36 per cent. ?? 1973.

  9. Effect of noble gases on oxygen and glucose deprived injury in human tubular kidney cells.

    PubMed

    Rizvi, Maleeha; Jawad, Noorulhuda; Li, Yuantao; Vizcaychipi, Marcela P; Maze, Mervyn; Ma, Daqing

    2010-07-01

    The noble gas xenon has been shown to be protective in preconditioning settings against renal ischemic injury. The aims of this study were to determine the protective effects of the other noble gases, helium, neon, argon, krypton and xenon, on human tubular kidney HK2 cells in vitro. Cultured human renal tubular cells (HK2) were exposed to noble gas preconditioning (75% noble gas; 20% O(2); 5% CO(2)) for three hours or mock preconditioning. Twenty-four hours after gas exposure, cell injury was provoked with oxygen-glucose deprived (OGD) culture medium for three hours. Cell viability was assessed 24 h post-OGD by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Other cohorts of cultured cells were incubated in the absence of OGD in 75% noble gas, 20% O(2) and 5% CO(2) and cellular signals phospho-Akt (p-Akt), hypoxia-inducible factor-1alpha (HIF-1alpha) and Bcl-2 were assessed by Western blotting. OGD caused a reduction in cell viability to 0.382 +/- 0.1 from 1.0 +/- 0.15 at control (P < 0.01). Neon, argon and krypton showed no protection from injury (0.404 +/- 0.03; 0.428 +/- 0.02; 0.452 +/- 0.02; P > 0.05). Helium by comparison significantly enhanced cell injury (0.191 +/- 0.05; P < 0.01). Xenon alone exerted a protective effect (0.678 +/- 0.07; P < 0.001). In the absence of OGD, helium was also detrimental (0.909 +/- 0.07; P < 0.01). Xenon caused an increased expression of p-Akt, HIF-1alpha and Bcl-2, while the other noble gases did not modify protein expression. These results suggest that unlike other noble gases, preconditioning with the anesthetic noble gas xenon may have a role in protection against renal ischemic injury.

  10. Noble gases in gas shales : Implications for gas retention and circulating fluids.

    NASA Astrophysics Data System (ADS)

    Basu, Sudeshna; Jones, Adrian; Verchovsky, Alexander

    2016-04-01

    Gas shales from three cores of Haynesville-Bossier formation have been analysed simultaneously for carbon, nitrogen and noble gases (He, Ne, Ar, Xe) to constrain their source compositions and identify signatures associated with high gas retention. Ten samples from varying depths of 11785 to 12223 feet from each core, retrieved from their centres, have been combusted from 200-1200°C in incremental steps of 100°C, using 5 - 10 mg of each sample. Typically, Xe is released at 200°C and is largely adsorbed, observed in two of the three cores. The third core lacked any measureable Xe. High 40Ar/36Ar ratio up to 8000, is associated with peak release of nitrogen with distinctive isotopic signature, related to breakdown of clay minerals at 500°C. He and Ne are also mostly released at the same temperature step and predominantly hosted in the pore spaces of the organic matter associated with the clay. He may be produced from the uranium related to the organic matter. The enrichment factors of noble gases defined as (iX/36Ar)sample/(iX/36Ar)air where iX denotes any noble gas isotope, show Ne and Xe enrichment observed commonly in sedimentary rocks including shales (Podosek et al., 1980; Bernatowicz et al., 1984). This can be related to interaction of the shales with circulating fluids and diffusive separation of gases (Torgersen and Kennedy, 1999), implying the possibility of loss of gases from these shales. Interaction with circulating fluids (e.g. crustal fluids) have been further confirmed using 20Ne/N2, 36Ar/N2 and 4He/N2 ratios. Deviations of measured 4He/40Ar* (where 40Ar* represents radiogenic 40Ar after correcting for contribution from atmospheric Ar) from expected values has been used to monitor gas loss by degassing. Bernatowicz, T., Podosek, F.A., Honda, M., Kramer, F.E., 1984. The Atmospheric Inventory of Xenon and Noble Gases in Shales: The Plastic Bag Experiment. Journal of Geophysical Research 89, 4597-4611. Podosek, F.A., Honda, M., Ozima, M., 1980

  11. Incorporation of Solar Noble Gases from a Nebula-Derived Atmosphere During Magma Ocean Cooling

    NASA Technical Reports Server (NTRS)

    Woolum, D. S.; Cassen, P.; Wasserburg, G. J.; Porcelli, D.; DeVincenzi, Donald (Technical Monitor)

    1998-01-01

    The presence of solar noble gases in the deep interior of the Earth is inferred from the Ne isotopic compositions of MORB (Mid-ocean Ridge Basalts) and OIB (Oceanic Island Basalt); Ar data may also consistent with a solar component in the deep mantle. Models of the transport and distribution of noble gases in the earth's mantle allow for the presence of solar Ar/Ne and Xe/Ne ratios and permit the calculation of lower mantle noble gas concentrations. These mantle data and models also indicate that the Earth suffered early (0.7 to 2 x 10(exp 8) yr) and large (greater than 99 percent) losses of noble gases from the interior, a result previously concluded for atmospheric Xe. We have pursued the suggestion that solar noble gases were incorporated in the forming Earth from a massive, nebula-derived atmosphere which promoted large-scale melting, so that gases from this atmosphere dissolved in the magma ocean and were mixed downward. Models of a primitive atmosphere captured from the solar nebula and supported by accretion luminosity indicate that pressures at the Earth's surface were adequate (and largely more than the required 100 Atm) to dissolve sufficient gases. We have calculated the coupled evolution of the magma ocean and the overlying atmosphere under conditions corresponding to the cessation (or severe attenuation) of the sustaining accretion luminosity, prior to the complete removal of the solar nebula. Such a condition was likely to obtain, for instance, when most of the unaccumulated mass resided in large bodies which were only sporadically accreted. The luminosity supporting the atmosphere is then that provided by the cooling Earth, consideration of which sets a lower limit to the time required to solidify the mantle and terminate the incorporation of atmospheric gases within it. In our initial calculations, we have fixed the nebula temperature at To = 300K, a value likely to be appropriate for nebular temperatures at lAU in the early planet-building epoch

  12. Noble Gas Systematics in MORBs and OIBs and Reconstitution of the Time-Evolution of Mantle Composition for Heavy Noble Gases: the Role of Subduction of Atmospheric Noble Gases.

    NASA Astrophysics Data System (ADS)

    Roubinet, C.; Moreira, M. A.

    2014-12-01

    Chondrites are considered as the building rocks of the Earth as they represent remnants of the protoplanetary accretion stage. Among all chondritic classes, heavy noble gases are mainly concentrated in phase Q [1] hence it represents a likely primordial composition of the Earth. This is supported by the observation of [2] who detected this peculiar composition in CO2 well gases thanks to Kr isotopes. As CO2 well gases are supposed to derive from the same reservoir as MORBs [3], this signature should be observed in MORBs and OIBs as well. In this perspective, we will present analyses performed by mass spectrometry of MORBs and OIBs samples for all noble gases. Preliminary results are quite promising as the same trend seems to appear into OIB and MORB data for Kr isotopes. However, our analyses show that this primordial composition isn't displayed for stable isotopes of Xe as already observed by [4-5] and remains a trace in the mantle signature, which appears at first sight atmospheric. We thus propose that subduction of atmospheric noble gases has gradually covered this meteoritic imprint. In order to test this scenario, we will present a modelling performed for Ar and Xe in three distinct reservoirs: mantle, atmosphere and continental crust. The mantle is considered as homogenized by convection and similar to the MORB reservoir. Its degasing is divided in two stages: a massive early degasing followed by a decreasing one describing the cooling of the Earth's interior. Extraction of parent elements from the mantle to the continental crust is also taken into account as well as distillation of atmospheric Xe needed to explain the missing Xe paradox and the present Xe isotopic signature of the atmosphere. Finally, subduction of noble gases is assimilated to simple incorporation into the mantle of elementally fractionated air, enriched in heavy noble gases as supported by [6]. Thus, we show that starting with a chondritic composition, the present mantle composition can

  13. Release of radiogenic noble gases as a new signal of rock deformation

    NASA Astrophysics Data System (ADS)

    Bauer, Stephen J.; Gardner, W. Payton; Lee, Hyunwoo

    2016-10-01

    In this study we investigate the release of radiogenic noble gas isotopes during mechanical deformation. We developed an analytical system for dynamic mass spectrometry of noble gas composition and helium release rate of gas produced during mechanical deformation of rocks. Our results indicate that rocks release accumulated radiogenic helium and argon from mineral grains as they undergo deformation. We found that the release of accumulated 4He and 40Ar from rocks follows a reproducible pattern and can provide insight into the deformation process. Increased gas release can be observed before dilation, and macroscopic failure is observed during high-pressure triaxial rock deformation experiments. Accumulated radiogenic noble gases can be released due to fracturing of mineral grains during small-scale strain in Earth materials. Helium and argon are highly mobile, conservative species and could be used to provide information on changes in the state of stress and strain in Earth materials, and as an early warning signal of macroscopic failure. These results pave the way for the use of noble gases to trace and monitor rock deformation for earthquake prediction and a variety of other subsurface engineering projects.

  14. Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

    SciTech Connect

    Goodson, Boyd McLean

    1999-12-01

    Conventional nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are fundamentally challenged by the insensitivity that stems from the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This dissertation is primarily concerned with the principles and practice of optically pumped nuclear magnetic resonance (OPNMR). The enormous sensitivity enhancement afforded by optical pumping noble gases can be exploited to permit a variety of novel NMR experiments across many disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, and zero-field NMR and MRI.

  15. Adsorption behavior of ternary mixtures of noble gases inside single-walled carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

    Foroutan, Masumeh; Nasrabadi, Amir Taghavi

    2010-09-01

    In order to study the gas-storage and gas-filtering capability of carbon nanotube (CNT) bundles simultaneously, we considered the adsorption behavior of a ternary mixture of noble gases, including Argon (Ar), Krypton (Kr), and Xenon (Xe), i.e., Ar-Kr-Xe mixture, on (10, 10) single-walled carbon nanotube (SWCNT) bundles. Molecular dynamics (MD) simulations at different temperatures of (75, 100, 150, 200, 250, and 300) K were performed, and adsorption energies, self-diffusion coefficients, activation energies, and radial distribution functions (RDFs) were computed to analyze the thermodynamics, transport and structural properties of the adsorption systems. It is observed that the SWCNT bundles have larger contents of heavier noble gases compared to the lighter ones. This interesting behavior of SWCNT bundles makes them proper candidates for gas-storage and gas molecular-sieving processes.

  16. Terrestrial nitrogen and noble gases in lunar soils.

    PubMed

    Ozima, M; Seki, K; Terada, N; Miura, Y N; Podosek, F A; Shinagawa, H

    2005-08-04

    The nitrogen in lunar soils is correlated to the surface and therefore clearly implanted from outside. The straightforward interpretation is that the nitrogen is implanted by the solar wind, but this explanation has difficulties accounting for both the abundance of nitrogen and a variation of the order of 30 per cent in the 15N/14N ratio. Here we propose that most of the nitrogen and some of the other volatile elements in lunar soils may actually have come from the Earth's atmosphere rather than the solar wind. We infer that this hypothesis is quantitatively reasonable if the escape of atmospheric gases, and implantation into lunar soil grains, occurred at a time when the Earth had essentially no geomagnetic field. Thus, evidence preserved in lunar soils might be useful in constraining when the geomagnetic field first appeared. This hypothesis could be tested by examination of lunar farside soils, which should lack the terrestrial component.

  17. Numerical investigation of enhanced femtosecond supercontinuum via a weak seed in noble gases.

    PubMed

    Shanor, C; Ensley, T; Hagan, D J; Van Stryland, E W; Wright, E M; Kolesik, M

    2016-06-27

    Numerical simulations are employed to elucidate the physics underlying the enhanced femtosecond supercontinuum generation previously observed during optical filamentation in noble gases and in the presence of a weak seed pulse. Simulations based on the metastable electronic state approach are shown not only to capture the qualitative features of the experiment, but also reveal the relation of the observed enhancement to recent developments in the area of sub-cycle engineering of filaments.

  18. The role of van der Waals interactions in the adsorption of noble gases on metal surfaces

    SciTech Connect

    Chen, De-Li; Al-Saidi, W A; Johnson, J Karl

    2012-10-03

    Adsorption of noble gases on metal surfaces is determined by weak interactions. We applied two versions of the nonlocal van der Waals density functional (vdW-DF) to compute adsorption energies of Ar, Kr, and Xe on Pt(111), Pd(111), Cu(111), and Cu(110) metal surfaces. We have compared our results with data obtained using other density functional approaches, including the semiempirical vdW corrected DFT-D2. The vdW-DF results show considerable improvements in the description of adsorption energies and equilibrium distances over other DFTbased methods, giving good agreement with experiments. We have also calculated perpendicular vibrational energies for noble gases on the metal surfaces using vdWDF data and found excellent agreement with available experimental results. Our vdW-DF calculations show that adsorption of noble gases on low-coordination sites is energetically favored over high-coordination sites, but only by a few meV. Analysis of the 2-dimensional potential energy surface shows that the high-coordination sites are local maxima on the 2-dimensional potential energy surface and therefore unlikely to be observed in experiments, which provides an explanation of the experimental observations. The DFT-D2 approach with the standard parameterization was found to overestimate the dispersion interactions, and to give the wrong adsorption site preference for four of the nine systems we studied.

  19. Radiative precursors driven by converging blast waves in noble gases

    SciTech Connect

    Burdiak, G. C.; Lebedev, S. V.; Harvey-Thompson, A. J.; Swadling, G. F.; Suzuki-Vidal, F.; Hall, G. N.; Khoory, E.; Pickworth, L.; Bland, S. N.; Grouchy, P. de; Skidmore, J.; Suttle, L.; Bennett, M.; Niasse, N. P. L.; Williams, R. J. R.; Blesener, K.; Atoyan, L.; Cahill, A.; Hoyt, C.; Potter, W.; and others

    2014-03-15

    A detailed study of the radiative precursor that develops ahead of converging blast waves in gas-filled cylindrical liner z-pinch experiments is presented. The experiment is capable of magnetically driving 20 km s{sup −1} blast waves through gases of densities of the order 10{sup −5} g cm{sup −3} (see Burdiak et al. [High Energy Density Phys. 9(1), 52–62 (2013)] for a thorough description). Data were collected for Ne, Ar, and Xe gas-fills. The geometry of the setup allows a determination of the plasma parameters both in the precursor and across the shock, along a nominally uniform line of sight that is perpendicular to the propagation of the shock waves. Radiation from the shock was able to excite NeI, ArII, and XeII/XeIII precursor spectral features. It is shown that the combination of interferometry and optical spectroscopy data is inconsistent with upstream plasmas being in LTE. Specifically, electron density gradients do not correspond to any apparent temperature change in the emission spectra. Experimental data are compared to 1D radiation hydrodynamics HELIOS-CR simulations and to PrismSPECT atomic physics calculations to assist in a physical interpretation of the observations. We show that upstream plasma is likely in the process of being radiatively heated and that the emission from a small percentage of ionised atoms within a cool background plasma dominates the emission spectra. Experiments were carried out on the MAGPIE and COBRA pulsed-power facilities at Imperial College London and Cornell University, respectively.

  20. The solubility of noble gases in crude oil at 25-100°C

    USGS Publications Warehouse

    Kharaka, Yousif K.; Specht, Daniel J.

    1988-01-01

    The solubility of the noble gases He, Ne, Ar, Kr and Xe was measured in two typical crude oils at temperatures of 25–100°C. The oil samples were obtained from the Elk Hills oil field located in southern San Joaquin Valley, California. The experimental procedure consisted of placing a known amount of gas with a known volume of crude oil in a stainless steel hydrothermal pressure vessel. The vessel was housed inside an oven and the entire unit rotates providing continuous mixing. The amount of gas dissolved in oil at a measured temperature and partial pressure of gas was used to calculate the solubility constants for these gases. Results show that the solubility of He and Ne in both oils is approximately the same; solubility then increases with atomic mass, with the solubility of Xe at 25°C being two orders of magnitude higher than that of He. The gas solubilities are somewhat higher in the lower density (higher API gravity) oil. The solubility of Ar is approximately constant in the range of temperatures of this study. The solubilities of He and Ne increase, but those of Kr and Xe decrease with increasing temperatures. Solubilities of noble gases in crude oil are significantly higher than their solubilities in water. For example, the solubilities of He and Xe at 25°C in the light oil of this study are, respectively, 3 and 24 times higher than their solubilities in pure water, and they are 15 and 300 times higher than in a brine with a salinity of 350,000 mg/l dissolved solids. These large and variable differences in the solubilities of noble gases in oil and water indicate that, in sedimentary basins with oil, these gases must be partitioned between oil, water and natural gas before they are used to deduce the origin and residence time of these fluids.

  1. Identifying Glacial Meltwater Sources in Greenland using Noble Gases as Tracers

    NASA Astrophysics Data System (ADS)

    Niu, Y.; Castro, M. C.; Aciego, S.; Hall, C. M.; Stevenson, E. I.; Arendt, C. A.; Das, S. B.

    2015-12-01

    We present a noble gas study in glacial meltwater (GMW) from the Greenland Ice Sheet. It explores the information noble gases can provide in glacial environments with respect to GMW sources, relative source contributions, water residence times, and spatial locations where this GMW originates within the ice sheet. This study seeks to improve our understanding of the dynamics of the ice sheets, critical for the major role they play in climate change. This is possible due to the conservative nature of noble gases and the temperature dependency of their concentrations in water in equilibrium with the atmosphere (ASW) which allows estimation of the altitude at which GMW originated. In addition, crustal He accumulates in water over time, allowing for estimation of water residence times. GMW samples were collected at five locations in southern Greenland. Results show that the major source of subglacial meltwater is ASW rather than old, compressed glacial ice, which has a distinct noble gas signature not seen in our samples. Given that, GMW samples do deviate to a certain extent from ASW, with concentrations displaying two distinct patterns. The first one presents a relative Ar enrichment with respect to Ne, Kr, and Xe, first observed in high-altitude springs in the Galápagos Islands (Warrier et al., 2012). The second one displays a mass-dependent pattern, first observed in Michigan rainwater (Warrier et al., 2013). Ne and Xe analysis suggests that about half of the samples equilibrated at a temperature of ~0°C and altitudes between 1 km and 2 km, with a few samples pointing to lower equilibration altitudes and temperatures between 2°C and 5°C. Two samples suggest an origin as melted ice and lack of equilibration with surface conditions. He concentrations vary between 1.1 and 7 times that of ASW and suggest glacial meltwater ages between 100 and 3600 yrs, a result that is consistent with a preliminary 3H analysis. References: Warrier, R. B., Castro, M. C., and Hall, C

  2. Sorption of noble gases by solids, with reference to meteorites. I - Magnetite and carbon

    NASA Technical Reports Server (NTRS)

    Yang, J.; Lewis, R. S.; Anders, E.

    1982-01-01

    The trapping of meteoritic noble gases by solids is simulated through the synthesis of 18 Fe3O4 samples at 350-720 K in a noble gas atmosphere, by means of the reactions: (1) 3Fe + 4H2O yields Fe3O4 + 4H2, using Ne, Ar, Kr and Xe; and (2) 3Fe + 4CO yields Fe3O4 + 4C + carbides, using Xe. Etching experiments suggest an analogy with 'Phase Q' in meteorites. Adsorbed atmospheric gases are present in all samples, and dominate whenever the noble gas partial pressure in the atmosphere is greater than that in the synthesis. While many of the results of Lancet and Anders (1973) appear to have been dominated by such an atmospheric component, others are suspect. When the doubtful samples of Lancet and Anders are corrected or eliminated, the fractionation pattern no longer peaks at Ar, but rather, as in the present sample, rises monotonically from Ne to Xe. No evidence is found for the earlier study's claim of a strong temperature dependence.

  3. Mass fractionation of noble gases in synthetic methane hydrate: Implications for naturally occurring gas hydrate dissociation

    USGS Publications Warehouse

    Hunt, Andrew G.; Stern, Laura; Pohlman, John W.; Ruppel, Carolyn; Moscati, Richard J.; Landis, Gary P.

    2013-01-01

    As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the ocean-atmosphere system. A key challenge in assessing the impact of dissociating gas hydrates on global atmospheric methane is the lack of a technique able to distinguish between methane recently released from gas hydrates and methane emitted from leaky thermogenic reservoirs, shallow sediments (some newly thawed), coal beds, and other sources. Carbon and deuterium stable isotopic fractionation during methane formation provides a first-order constraint on the processes (microbial or thermogenic) of methane generation. However, because gas hydrate formation and dissociation do not cause significant isotopic fractionation, a stable isotope-based hydrate-source determination is not possible. Here, we investigate patterns of mass-dependent noble gas fractionation within the gas hydrate lattice to fingerprint methane released from gas hydrates. Starting with synthetic gas hydrate formed under laboratory conditions, we document complex noble gas fractionation patterns in the gases liberated during dissociation and explore the effects of aging and storage (e.g., in liquid nitrogen), as well as sampling and preservation procedures. The laboratory results confirm a unique noble gas fractionation pattern for gas hydrates, one that shows promise in evaluating modern natural gas seeps for a signature associated with gas hydrate dissociation.

  4. Sorption of noble gases by solids, with reference to meteorites. I - Magnetite and carbon

    NASA Astrophysics Data System (ADS)

    Yang, J.; Lewis, R. S.; Anders, E.

    1982-06-01

    The trapping of meteoritic noble gases by solids is simulated through the synthesis of 18 Fe3O4 samples at 350-720 K in a noble gas atmosphere, by means of the reactions: (1) 3Fe + 4H2O yields Fe3O4 + 4H2, using Ne, Ar, Kr and Xe; and (2) 3Fe + 4CO yields Fe3O4 + 4C + carbides, using Xe. Etching experiments suggest an analogy with 'Phase Q' in meteorites. Adsorbed atmospheric gases are present in all samples, and dominate whenever the noble gas partial pressure in the atmosphere is greater than that in the synthesis. While many of the results of Lancet and Anders (1973) appear to have been dominated by such an atmospheric component, others are suspect. When the doubtful samples of Lancet and Anders are corrected or eliminated, the fractionation pattern no longer peaks at Ar, but rather, as in the present sample, rises monotonically from Ne to Xe. No evidence is found for the earlier study's claim of a strong temperature dependence.

  5. Sorption of noble gases by solids, with reference to meteorites. II - Chromite and carbon. III - Sulfides, spinels, and other substances; on the origin of planetary gases

    NASA Technical Reports Server (NTRS)

    Yang, J.; Anders, E.

    1982-01-01

    The trapping of noble gases by chromite and carbon, two putative carriers of primordial noble gases in meteorites, was studied by synthesizing 19 samples in a Ne-Ar-Kr-Xe atmosphere at 440-720 K. Noble gas contents are found to approximately obey Henry's Law, but only slight correlations are found with composition, surface area, or adsorption temperature. Geometric mean distribution coefficients for bulk samples and HCl residues in 10 cu cm STP/g atm are: Xe 100, Kr 15, Ar 3.5, and Ne 0.62. Elemental fractionation data support the suggestion of Lewis et al. (1977) that chromite and carbon in C2 and C3 chondrites were formed by the reaction: Fe, Cr + 4CO yields (Fe, Cr)3O4 + 4C + carbides. In contrast to meteoritic minerals, the synthetic specimens show no isotopic fractionation of noble gases. In a subsequent study, attention is given to the cases of sulfides and spinels, on the way to consideration of the origin of planetary gases. Sulfides showed three distinctive trends relative to chromite or magnetite. The elemental fractionation pattern of Ar, Kr and Xe in meteorites, terrestrial rocks and planets resembles the adsorption patterns on the carbons, spinels, sulfides, and other solids studied. The high release temperature of meteoritic noble gases may be explained by transformation of the physisorbed or chemisorbed gas. The ready loss of meteoritic heavy gases on surficial oxidation is consistent with adsorption, as is the high abundance.

  6. Properties of Laser Produced TMAE Plasma Admixed with Air Constituents, Nitrogen and Noble Gases

    NASA Astrophysics Data System (ADS)

    Ding, Guowen; Scharer, John; Kelly, Kurt

    1999-10-01

    A high initial density (> 10^13 cm-3) and a large volume (hundreds of cm^3) plasma is created by a 193 nm laser ionization of an organic molecule, tetrakis(dimethyl-amino)ethylene(TMAE). The properties of this plasma mixed with nitrogen and noble gases are studied. Fast probe measurements which include a detailed considerations of probe structure, probe surface cleaning, shielding, probe perturbation, frequency response, temporal and spatial resolutions, dummy probe corrections and noise analysis will be described. Electron densities obtained by this method are independent on the ion species mixture. A plasma emission diagnostic is used to estimate plasma densities for the higher admixture pressures. Electron density and temperature vs. time for various TMAE, nitrogen and noble gas pressures and laser power will be presented. The role of super-excited and metastable states in the decay process will also be discussed.

  7. Noble gases solubility models of hydrocarbon charge mechanism in the Sleipner Vest gas field

    NASA Astrophysics Data System (ADS)

    Barry, P. H.; Lawson, M.; Meurer, W. P.; Warr, O.; Mabry, J. C.; Byrne, D. J.; Ballentine, C. J.

    2016-12-01

    Noble gases are chemically inert and variably soluble in crustal fluids. They are primarily introduced into hydrocarbon reservoirs through exchange with formation waters, and can be used to assess migration pathways and mechanisms, as well as reservoir storage conditions. Of particular interest is the role groundwater plays in hydrocarbon transport, which is reflected in hydrocarbon-water volume ratios. Here, we present compositional, stable isotope and noble gas isotope and abundance data from the Sleipner Vest field, in the Norwegian North Sea. Sleipner Vest gases are generated from primary cracking of kerogen and the thermal cracking of oil. Gas was emplaced into the Sleipner Vest from the south and subsequently migrated to the east, filling and spilling into the Sleipner Ost fields. Gases principally consist of hydrocarbons (83-93%), CO2 (5.4-15.3%) and N2 (0.6-0.9%), as well as trace concentrations of noble gases. Helium isotopes (3He/4He) are predominantly radiogenic and range from 0.065 to 0.116 RA; reported relative to air (RA = 1.4 × 10-6; Clarke et al., 1976; Sano et al., 1988), showing predominantly (>98%) crustal contributions, consistent with Ne (20Ne/22Ne from 9.70 to 9.91; 21Ne/22Ne from 0.0290 to 0.0344) and Ar isotopes (40Ar/36Ar from 315 to 489). Air-derived noble gas isotopes (20Ne, 36Ar, 84Kr, 132Xe) are introduced into the hydrocarbon system by direct exchange with air-saturated water (ASW). The distribution of air-derived noble gas species are controlled by phase partitioning processes; in that they preferentially partition into the gas (i.e., methane) phase, due to their low solubilities in fluids. Therefore, the extent of exchange between hydrocarbon phases and formation waters - that have previously equilibrated with the atmosphere - can be determined by investigating air-derived noble gas species. We utilize both elemental ratios to address process (i.e., open vs. closed system) and concentrations to quantify the extent of hydrocarbon

  8. Subduction zone fluxes of halogens and noble gases in seafloor and forearc serpentinites

    NASA Astrophysics Data System (ADS)

    Kendrick, Mark A.; Honda, Masahiko; Pettke, Thomas; Scambelluri, Marco; Phillips, David; Giuliani, Andrea

    2013-03-01

    Serpentinites form by hydration of ultramafic lithologies in a range of seafloor and shallow subduction zone settings. Serpentinites are recognised as major reservoirs of fluid mobile elements and H2O in subducting oceanic lithosphere, and together with forearc serpentinites formed in the mantle wedge, provide critical information about shallow-level volatile fluxes during subduction. The current study provides new Cl, as well as the first comprehensive Br, I and noble gas analyses reported for seafloor and forearc chrysotile-lizardite serpentinites. The samples were recovered from IODP drilling campaigns of mid-ocean ridge, passive margin and forearc settings (n=17), and ophiolites in the Italian Alps and Apennines (n=10). The aims of this study were to determine the compositional variability of noble gases and halogens in serpentinites entering subduction zones and evaluate the efficiency of gas loss during the early stages of serpentinite subduction. The chrysotile-lizardite serpentinites and serpentised peridotites contain 43-2300 ppm Cl and 3×10-13-2×10-11 mol g-136Ar, with the concentrations of these elements broadly related to the estimated degree of serpentinisation. The serpentinites have extremely variable Br/Cl and I/Cl ratios with many samples preserving compositions similar to organic-rich sedimentary marine pore fluids. Serpentinites from the Marianas Forearc have very high I concentrations of up to 45 ppm I and I/Cl ratios of ˜14,000 times the seawater value that is even higher than the maximum I/Cl enrichment observed in sedimentary marine pore fluids. The serpentinites have 130Xe/36Ar and 84Kr/36Ar ratios that are mostly close to or above seawater values, and 20Ne/36Ar ratios that range from seawater to lower values. The serpentinites contain <10-270 ppm K and, irrespective of age (0 Ma to ˜160 Ma), are characterised by 40Ar/36Ar ratios of 300-340 that are slightly higher than the seawater value of 296, thus indicating the presence of minor

  9. Degassing and contamination of noble gases in Mid-Atlantic Ridge basalts

    NASA Astrophysics Data System (ADS)

    Burnard, P.; Harrison, D.; Turner, G.; Nesbitt, R.

    2003-01-01

    New He, Ne, Ar and CO2 stepped-crushing data from the Mid-Atlantic Ridge show that contamination of basalts by atmospheric noble gases involves three or more components: unfractionated air, fractionated air with high 36Ar/22Ne (≥45) and fractionated air with low 36Ar/22Ne (≤5). In addition, the magmatic noble gases trapped in these basaltic glasses are variably fractionated such that 4He/40Ar* (where the asterisk indicates corrected for atmospheric contamination based on all 36Ar being atmospheric in origin) is in the range 3-12. Single samples have a range in 4He/40Ar* with the highest ratios in the final crush steps, consistent with the most fractionated (highest 4He/40Ar*) volatiles trapped in the smallest vesicles. It is not possible to distinguish between batch and Rayleigh degassing mechanisms. The complexities of the contamination and magmatic fractionation processes means that it is not possible to estimate 40Ar/36Ar of the mantle source to these basalts other than it must be higher than the highest ratio measured (26,200 ± 5200). Noble gas/CO2 ratios are also variable. While some CO2 adsorption during crushing exaggerates the variations in He/CO2 and Ar/CO2, we show that it is not possible to account for the entire variation as an analytical artefact: some of the variation is present in the vesicles. Variations in He/CO2 cannot be attributed to solubility controlled degassing because of the broadly similar solubilities of He and CO2 in tholeiitic magmas. The large range in He/CO2 in these glasses (factor of 10) is not accompanied by indications of major changes in melting regime or source region chemistry, therefore is thought to reflect late-stage (magmatic) fractionation of CO2 from the noble gases. It is not possible to identify an explicit mechanism, although both CO2 reduction (e.g., to hydrocarbons or graphite) and kinetic CO2-noble gas fractionation could account for the variations.

  10. The quest for regolithic howardites. Part 2: Surface origins highlighted by noble gases

    NASA Astrophysics Data System (ADS)

    Cartwright, J. A.; Ott, U.; Mittlefehldt, D. W.

    2014-09-01

    neon release pattern similar to our defined planetary/FSW dominated regolithic group (CM-rich samples PRA 04401, SCO 06040). Our petrological investigations found no evidence for CM fragments within EET 87513, though a single clast was reported previously (Buchanan et al., 1993). Aside from the Ne release pattern, the remaining noble gas data show more similarity with SW/FSW components. The remaining four howardites CRE 01400, EET 87518, EET 99400, and SAN 03472 and are dominated by cosmogenic noble gases, and show no evidence for a regolithic origin. Our data suggest that a CM-composition is likely present in all samples to some degree, but that this can be overprinted by SW components or cosmogenic components obtained in situ on the vestan surface or during transit to Earth respectively. The presence of CM material is an important parameter for understanding the evolution of Vesta's surface. While we have uncovered three further regolithic howardites (∼13 regolithic total, of ∼41 analysed), further noble gas analysis of HED meteorites is needed to not only determine regolithic origins, but to better characterise the abundance of carbonaceous chondrite material and its effect on the noble gas signatures of such samples.

  11. Are protonated ions efficient sequestration agents for noble gases in the primitive nebula context?

    NASA Astrophysics Data System (ADS)

    Pauzat, Françoise; Ellinger, Yves; ozgurel, Ozge; Bacchus-montabonel, Marie-christine; Mousis, Olivier; Laboratoire de Chimie Théorique, Institut Lumière Matière, Laboratoire d'Astrophysique de Marseille

    2016-10-01

    One explanation for the deficiencies of argon, krypton and xenon observed in the atmosphere of Titan might be related to a scenario of sequestration by H3+ in the gas phase at the early evolution of the solar nebula. The chemical process implied is a radiative association, evaluated as rather efficient in the case of H3+, especially for krypton and xenon. In fact, this mechanism of chemical trapping might not be limited to H3+ only, considering that the protonated ions produced in the destruction of H3+ by its main competitors, namely H2O, CO and N2, present in the primitive nebula, might also give stable complexes with the noble gases.Here, the reactivity of the noble gases Ar, Kr, Xe, with all the protonated ions issued from H2O, CO and N2, expected to be present in the nebula with reasonably high abundances, i.e. H3O+, HCO+, HOC+, N2H+, has been studied with quantum simulation methods, quantum dynamics included. All of them give stable complexes; the rate coefficients of their radiative associations have been calculated as a function of temperature between 10 and 100 °K and found ranging from 10-18 to 10-16 cm3s-1, which can be considered as high for this type of reactions and are comparable to the rates obtained with H3+.Consequently, we can consider this process as universal for all protonated ions, which, if present in the primitive nebula as astrophysical models predict, should act as efficient sequestration agents for all three noble gases, in addition to the original H3+ captor.

  12. Stable Single-Bubble Sonoluminescence without the presence of noble gases

    NASA Astrophysics Data System (ADS)

    Levinsen, M. T.; Dam, J. S.

    2007-10-01

    We report that in spite of the commonly accepted view that stable Single-Bubble Sonoluminescence (SBSL) can only be achieved in water in the presence of a noble gas or hydrogen, long term stable SBSL can in fact be sustained with only diatomic gases like e.g. nitrogen being present. Compared to that of a stable argon bubble, the emission is much weaker and the spectrum looks much colder. Simulations support that the above quoted view, based on the dissociation hypothesis, is an erroneous inference from this theory.

  13. Enhancement of NMR and MRI in the presence of hyperpolarized noble gases

    DOEpatents

    Pines, Alexander; Budinger, Thomas; Navon, Gil; Song, Yi-Qiao; Appelt, Stephan; Bifone, Angelo; Taylor, Rebecca; Goodson, Boyd; Seydoux, Roberto; Room, Toomas; Pietrass, Tanja

    2004-11-16

    The present invention relates generally to nuclear magnetic resonance (NMR) techniques for both spectroscopy and imaging. More particularly, the present invention relates to methods in which hyperpolarized noble gases (e.g., Xe and He) are used to enhance and improve NMR and MRI. Additionally, the hyperpolarized gas solutions of the invention are useful both in vitro and in vivo to study the dynamics or structure of a system. When used with biological systems, either in vivo or in vitro, it is within the scope of the invention to target the hyperpolarized gas and deliver it to specific regions within the system.

  14. Calibration of stack monitors for measurement of noble gases in nuclear facilities.

    PubMed

    Kovar, Petr; Dryak, Pavel; Suran, Jiri; Gudelis, Arunas

    2012-09-01

    In nuclear facilities stack monitors are used for the measurement of the volumetric activity of noble gases. Spectrometric measurement is needed because the content of stack effluents is always a mixture of radionuclides. In some nuclear power plants new types of monitors were installed based on HPGe detectors. For efficiency calibration a standard with the radionuclide Xe-127 was developed and calibration curve constructed in the energy range 81 keV-1293 keV. Experiental efficiencies were checked using an MC model.

  15. Highly concentrated nebular noble gases in porous nanocarbon separates from the Saratov (L4) meteorite

    SciTech Connect

    Amari, Sachiko; Matsuda, Jun-ichi; Stroud, Rhonda M.; Chisholm, Matthew F.

    2013-11-20

    The majority of heavy noble gases (Ar, Kr, and Xe) in primitive meteorites are stored in a poorly understood phase called Q. Although Q is thought to be carbonaceous, the full identity of the phase has remained elusive for almost four decades. In order to better characterize phase Q and, in turn, the early solar nebula, we separated carbon-rich fractions from the Saratov (L4) meteorite. We chose this meteorite because Q is most resistant in thermal alteration among carbonaceous noble gas carriers in meteorites and we hoped that, in this highly metamorphosed meteorite, Q would be present but not diamond: these two phases are very difficult to separate from each other. One of the fractions, AJ, has the highest {sup 132}Xe concentration of 2.1 × 10{sup –6} cm{sup 3} STP g{sup –1}, exceeding any Q-rich fractions that have yet been analyzed. Transmission electron microscopy studies of the fraction AJ and a less Q-rich fraction AI indicate that they both are primarily porous carbon that consists of domains with short-range graphene orders, with variable packing in three dimensions, but no long-range graphitic order. The relative abundance of Xe and C atoms (6:10{sup 9}) in the separates indicates that individual noble gas atoms are associated with only a minor component of the porous carbon, possibly one or more specific arrangements of the nanoparticulate graphene.

  16. Gravity effects on a gliding arc in four noble gases: from normal to hypergravity

    NASA Astrophysics Data System (ADS)

    Potočňáková, L.; Šperka, J.; Zikán, P.; van Loon, J. J. W. A.; Beckers, J.; Kudrle, V.

    2015-04-01

    A gliding arc in four noble gases (He, Ne, Ar, Kr) has been studied under previously unexplored conditions of varying artificial gravity, from normal 1 g gravity up to 18 g hypergravity. Significant differences, mainly the visual thickness of the plasma channel, its maximum elongation and general sensitivity to hypergravity conditions, were observed between the discharges in individual gases, resulting from their different atomic weights and related quantities, such as heat conductivity or ionisation potential. Generally, an increase of the artificial gravity level leads to a faster plasma channel movement thanks to stronger buoyant force and a decrease of maximum height reached by the channel due to more intense losses of heat and reactive species. In relation to this, an increase in current and a decrease in absorbed power was observed.

  17. Noble Gases in Two Fragments of Different Lithologies from the Almahata Sitta Meteorite

    NASA Technical Reports Server (NTRS)

    Nagao, K.; Haba, M. K.; Zolensky, M.; Jenniskens, P.; Shaddad, M. H.

    2014-01-01

    The Almahata Sitta meteorite, whose preat-mospheric body was the asteroid 2008 TC3, fell on October 7, 2008 in the Nubian Desert in northern Sudan [e.g., 1, 2]. Numer-ous fragments have been recovered during several expeditions organized from December 2008 [2]. The meteorite was classified as an anomalous polymict ureilite with several different kinds of chondritic fragments [e.g., 3-5]. Noble gas studies performed on several fragments from the meteorite showed cosmic-ray expo-sure ages of about 20 My [e.g., 6-8], although slightly shorter ages were also reported in [9, 10]. Concentrations of trapped heavy noble gases are variable among the fragments of different lithologies [9, 10]. We report noble gas data on two samples from the #1 and #47 fragments [2], which were the same as those re-ported by Ott et al. [9]. Experimental Procedure: Weights of bulk samples #1 and #47 used in this work were 16.1 mg and 17.6 mg, respectively. Noble gases were extracted by stepwise heating at the tempera-tures of 800, 1200 and 1800°C for #1 and 600, 800, 1000, 1200, 1400, 1600 and 1800°C for #47. Concentrations and isotopic ra-tios of noble gases were measured with a modified-VG5400/MS-III at the Geochemical Research Center, University of Tokyo. Results and Discussion: Cosmogenic He and Ne are domi-nant in both #1 and #47, but trapped Ar, Kr and Xe concentra-tions are much higher in #47 than in #1, showing that noble gas compositions in #47 are similar to those of ureilites. 3He/21Ne and 22Ne/21Ne of cosmogenic He and Ne are 4.8 and 1.12 for #1 and 3.6 and 1.06 for #47, respectively, both of which plot on a Bern line [11]. This indicates negligible loss of cosmogenic 3He from #1 in our sample, unlike the low 3He/21Ne of 3.1 for #1 by Ott et al. [9]. Concentrations of cosmogenic 3He and 21Ne (10-8 cc/g) are 30 and 6.3 for #1 and 32 and 9.0 for #47, respectively, which are higher than those in [9] and give cosmic-ray exposure ages of ca. 20 My depending on assumed production

  18. Bubble formation, vesicularity and fractionation of noble gases during MORB degassing

    NASA Astrophysics Data System (ADS)

    Sator, N.; Guillot, B. B.; Aubry, G.

    2012-12-01

    The fractionation of noble gases in oceanic basalts gives information on the source region and on the transport of volatiles up to the seafloor. For instance, the large distribution (~1-1,000) of the 4He/40Ar* ratio in mid-ocean ridge basalts (MORB), is interpreted as the signature of different degassing scenarios taking place at depth. Thus, a low value of this ratio is explained by a closed system degassing whereas a high value is assigned either to an open system degassing (where vesicles are lost in a magma chamber or at depth during magma ascent) or to a kinetic disequilibrium induced by a rapid magma ascent just prior eruption. Unfortunately, CO2 has a very low solubility in basaltic melts at pressure corresponding to the seafloor and an overwhelming majority of erupted lavas have lost their pristine volatile contents. However notable exceptions are the popping rocks characterized by a large vesicularity, a high CO2 content and a 4He/40Ar* ratio compatible with the expected U/K ratio of the upper mantle. Those samples likely have experienced a CO2 exsolution at about 35 km depth in the oceanic mantle. So, the very existence of these exceptional MORB samples suggests that CO2-rich melts could be present at a greater depth. Thus, explosive eruptions near ocean spreading centers are well documented (Hekinian et al., 2000) and are associated with volcaniclastic deposits containing highly vesicular basalts, a feature which suggests that this volcanism is driven by CO2-rich magmas (Helo et al., 2011). But how much CO2-rich are these magmas, that is the question. The objective of this study is to use molecular dynamics simulation (MD) to evaluate the vesicularity and the fractionation of noble gases in a degassing MORB melt. A previous simulation study (Guillot and Sator, 2011) has shown that the solubility of CO2 in basaltic melts increases steadily with the pressure and deviates significantly from the Henry's law at high pressures. From the CO2 solubility curve

  19. Investigation of Lung Structure-Function Relationships Using Hyperpolarized Noble Gases

    NASA Astrophysics Data System (ADS)

    Thomen, Robert P.

    Magnetic Resonance Imaging (MRI) is an application of the nuclear magnetic resonance (NMR) phenomenon to non-invasively generate 3D tomographic images. MRI is an emerging modality for the lung, but it suffers from low sensitivity due to inherent low tissue density and short T(*/2) . Hyperpolarization is a process by which the nuclear contribution to NMR signal is greatly enhanced to more than 100,000 times that of samples in thermal equilibrium. The noble gases 3He and 129Xe are most often hyperpolarized by transfer of light angular momentum through the electron of a vaporized alkali metal to the noble gas nucleus (called Spin Exchange Optical Pumping). The enhancement in NMR signal is so great that the gas itself can be imaged via MRI, and because noble gases are chemically inert, they can be safely inhaled by a subject, and the gas distribution within the interior of the lung can be imaged. The mechanics of respiration is an elegant physical process by which air is is brought into the distal airspaces of the lungs for oxygen/carbon dioxide gas exchange with blood. Therefore proper description of lung function is intricately related to its physical structure , and the basic mechanical operation of healthy lungs -- from pressure driven airflow, to alveolar airspace gas kinetics, to gas exchange by blood/gas concentration gradients, to elastic contraction of parenchymal tissue -- is a process decidedly governed by the laws of physics. This dissertation will describe experiments investigating the relationship of lung structure and function using hyperpolarized (HP) noble gas MRI. In particular HP gases will be applied to the study of several pulmonary diseases each of which demonstrates unique structure-function abnormalities: asthma, cystic fibrosis, and chronic obstructive pulmonary disease. Successful implementation of an HP gas acquisition protocol for pulmonary studies is an involved and stratified undertaking which requires a solid theoretical foundation in NMR

  20. Opacity and conductivity measurements in noble gases at conditions of planetary and stellar interiors.

    PubMed

    McWilliams, R Stewart; Dalton, D Allen; Konôpková, Zuzana; Mahmood, Mohammad F; Goncharov, Alexander F

    2015-06-30

    The noble gases are elements of broad importance across science and technology and are primary constituents of planetary and stellar atmospheres, where they segregate into droplets or layers that affect the thermal, chemical, and structural evolution of their host body. We have measured the optical properties of noble gases at relevant high pressures and temperatures in the laser-heated diamond anvil cell, observing insulator-to-conductor transformations in dense helium, neon, argon, and xenon at 4,000-15,000 K and pressures of 15-52 GPa. The thermal activation and frequency dependence of conduction reveal an optical character dominated by electrons of low mobility, as in an amorphous semiconductor or poor metal, rather than free electrons as is often assumed for such wide band gap insulators at high temperatures. White dwarf stars having helium outer atmospheres cool slower and may have different color than if atmospheric opacity were controlled by free electrons. Helium rain in Jupiter and Saturn becomes conducting at conditions well correlated with its increased solubility in metallic hydrogen, whereas a deep layer of insulating neon may inhibit core erosion in Saturn.

  1. Opacity and conductivity measurements in noble gases at conditions of planetary and stellar interiors

    PubMed Central

    McWilliams, R. Stewart; Dalton, D. Allen; Konôpková, Zuzana; Mahmood, Mohammad F.; Goncharov, Alexander F.

    2015-01-01

    The noble gases are elements of broad importance across science and technology and are primary constituents of planetary and stellar atmospheres, where they segregate into droplets or layers that affect the thermal, chemical, and structural evolution of their host body. We have measured the optical properties of noble gases at relevant high pressures and temperatures in the laser-heated diamond anvil cell, observing insulator-to-conductor transformations in dense helium, neon, argon, and xenon at 4,000–15,000 K and pressures of 15–52 GPa. The thermal activation and frequency dependence of conduction reveal an optical character dominated by electrons of low mobility, as in an amorphous semiconductor or poor metal, rather than free electrons as is often assumed for such wide band gap insulators at high temperatures. White dwarf stars having helium outer atmospheres cool slower and may have different color than if atmospheric opacity were controlled by free electrons. Helium rain in Jupiter and Saturn becomes conducting at conditions well correlated with its increased solubility in metallic hydrogen, whereas a deep layer of insulating neon may inhibit core erosion in Saturn. PMID:26080401

  2. The spectrum of density fluctuations of noble gases probed by THz neutron and x-ray spectroscopy

    SciTech Connect

    Cunsolo, Alessandro

    2016-02-26

    Approximately 50 years of inelastic scattering studies of noble gases are reviewed to illustrate the main advances achieved in the understanding of the THz dynamics of simple systems. The gradual departure of the spectral shape from the hydrodynamic regime is discussed with an emphasis on the phenomenology of fast (sub-ps) relaxation processes. This review shows that relaxation phenomena in noble gases have an essentially collisional origin, which is also revealed by the parallelism between their characteristic timescale and the interatomic collision time. In addition, recent THz spectroscopy results on noble gases at extreme thermodynamic conditions are discussed to illustrate the need for a revision of our current understanding of the supercritical phase.

  3. The spectrum of density fluctuations of noble gases probed by THz neutron and x-ray spectroscopy

    DOE PAGES

    Cunsolo, Alessandro

    2016-02-26

    Approximately 50 years of inelastic scattering studies of noble gases are reviewed to illustrate the main advances achieved in the understanding of the THz dynamics of simple systems. The gradual departure of the spectral shape from the hydrodynamic regime is discussed with an emphasis on the phenomenology of fast (sub-ps) relaxation processes. This review shows that relaxation phenomena in noble gases have an essentially collisional origin, which is also revealed by the parallelism between their characteristic timescale and the interatomic collision time. In addition, recent THz spectroscopy results on noble gases at extreme thermodynamic conditions are discussed to illustrate themore » need for a revision of our current understanding of the supercritical phase.« less

  4. Noble Gases and Nitrogen Released from a Lunar Soil Pyroxene Separate by Acid Etching

    NASA Astrophysics Data System (ADS)

    Rider, P. E.

    1993-07-01

    We report initial results from a series of experiments designed to measure recently implanted solar wind (SW) ions in lunar soil mineral grains [1]. An acid-etching technique similar to the CSSE method developed at ETH Zurich was used to make abundance and isotope measurements of the SW noble gas and nitrogen compositions. Among the samples examined was a pyroxene separate from soil 75081. It was first washed with H2O to remove contamination from the sample finger walls and grain surfaces. H2O also acted as a weak acid, releasing gases from near-surface sites. Treatment with H2SO3 followed the water washes. Acid pH (~1.8 to ~1.0) and temperature (~23 degrees C to ~90 degrees C) and duration of acid attack (several minutes to several days) were varied from step to step. Finally, the sample was pyrolyzed in several steps to remove the remaining gases, culminating with a high-temperature pyrolysis at 1200 degrees C. Measurements of the light noble gases were mostly consistent with those from previous CSSE experiments performed on pyroxene [2,3]. It should be noted, however, that the Zurich SEP component was not easily distinguishable in the steps where it was expected to be observed. We suspect our experimental protocol masked the SEP reservoir, preventing us from seeing its distinctive signature. The most interesting results from this sample are its Kr and Xe isotopic and elemental compositions. Pyroxene apparently retains heavy noble gases as well as ilmenite (and plagioclase [4]). The heavy noble gas element ratios from this sample along with those previously reported [5,6] are, however, considerably heavier than the theoretically determined "solar system" values [7,8]. Explanations for the difference include the possibility that the derivations are incorrect, that there is another component of lunar origin mixing with the solar component, or that some type of loss mechanism is altering the noble gas reservoirs of the grains. The Kr and Xe isotopic compositions for

  5. Effects of traces of molecular gases (hydrogen, nitrogen) in glow discharges in noble gases

    NASA Astrophysics Data System (ADS)

    Steers, E. B. M.; Smid, P.; Hoffmann, V.

    2008-07-01

    The "Grimm" type of low pressure glow discharge source, introduced some forty years ago, has proved to be a versatile analytical source. A flat sample is used as the cathode and placed about 0.2mm away from the end of a hollow tubular anode leading to an obstructed discharge. When the source was first developed, it was used for the direct analysis of solid metallic samples by optical emission spectroscopy (OES), normally with argon as the plasma gas; it was soon found that, using suitable electrical parameters, the cathode material was sputtered uniformly from a circular crater of diameter equal to that of the tubular anode, so that the technique could be used for compositional depth profile analysis (CDPA). Over the years the capability and applications of the technique have steadily increased. The use of rf powered discharges now permits the analysis of non-conducting layers and samples; improved instrumental design now allows CDPA of ever thinner layers (e.g. resolution of layers 5 nm thick in multilayer stacks is possible). For the original bulk material application, pre-sputtering could be used to remove any surface contamination but for CDPA, analysis must start immediately the discharge is ignited, so that any surface contamination can introduce molecular gases into the plasma gas and have significant analytical consequences, especially for very thin layers; in addition, many types of samples now analysed contain molecular gases as components (either as occluded gas, or e.g. as a nitride or oxide), and this gas enters the discharge when the sample is sputtered. It is therefore important to investigate the effect of such foreign gases on the discharge, in particular on the spectral intensities and hence the analytical results. The presentation will concentrate mainly on the effect of hydrogen in argon discharges, in the concentration range 0-2 % v/v but other gas mixtures (e.g. Ar/N_2, Ne/H_2) will be considered for comparison. In general, the introduction of

  6. Laboratory simulation of meteoritic noble gases. III - Sorption of neon, argon, krypton, and xenon on carbon - Elemental fractionation

    NASA Technical Reports Server (NTRS)

    Wacker, John F.

    1989-01-01

    The sorption of Ne, Ar, Kr, and Xe was studied in carbon black, acridine carbon, and diamond in an attempt to understand the origin of trapped noble gases in meteorites. The results support a model in which gases are physically adsorbed on interior surfaces formed by a pore labyrinth within amorphous carbons. The data show that: (1) the adsorption/desorption times are controlled by choke points that restrict the movement of noble gas atoms within the pore labyrinth, and (2) the physical adsorption controls the temperature behavior and elemental fractionation patterns.

  7. Solar wind noble gases and nitrogen in metal from lunar soil 68501

    NASA Technical Reports Server (NTRS)

    Becker, Richard H.; Pepin, Robert O.

    1994-01-01

    Noble gases and N were analyzed in handpicked metal separates from lunar soil 68501 by a combination of step-wise combustions and pyrolyses. Helium and Ne were found to be unfractionated with respect to one another when normalized to solar abundances, for both the bulk sample and for all but the highest temperature steps. However, they are depleted relative to Ar, Kr and Xe by at least a factor of 5. The heavier gases exhibit mass-dependent fractionation relative to solar system abundance ratios but appear unfractionated, both in the bulk metal and in early temperature steps, when compared to relative abundances derived from lunar ilmenite 71501 by chemical etching, recently put forward as representing the abundance ratios in solar wind. Estimates of the contribution of solar energetic particles (SEP) to the originally implanted solar gases, derived from a basic interpretation of He and Ne isotopes, yield values of about 10%. Analysis of the Ar isotopes requires a minimum of 20% SEP, and Kr isotopes, using our preferred composition for solar wind Kr, yield a result that overlaps both these values. It is possible to reconcile the data from these gases if significant loss of solar wind Ar, Kr and presumably Xe has occurred relative to the SEP component, most likely by erosive processes that are mass independent, although mass-dependent losses (Ar greater than Kr greater than Xe) cannot be excluded. If such losses did occur, the SEP contribution to the solar implanted gases must have been no more than a few percent. Nitrogen is a mixture of indigenous meteoritic N, whose isotopic composition is inferred to be relatively light, and implanted solar N, which has probably undergone diffusive redistribution and fractionation. If the heavy noble gases have not undergone diffusive loss, then N/Ar in the solar wind can be inferred to be at least several times the accepted solar ratio. The solar wind N appears, even after correction for fractionation effects, to have a minimum

  8. Solar wind noble gases and nitrogen in metal from lunar soil 68501

    NASA Astrophysics Data System (ADS)

    Becker, Richard H.; Pepin, Robert O.

    1994-09-01

    Noble gases and N were analyzed in handpicked metal separates from lunar soil 68501 by a combination of step-wise combustions and pyrolyses. Helium and Ne were found to be unfractionated with respect to one another when normalized to solar abundances, for both the bulk sample and for all but the highest temperature steps. However, they are depleted relative to Ar, Kr and Xe by at least a factor of 5. The heavier gases exhibit mass-dependent fractionation relative to solar system abundance ratios but appear unfractionated, both in the bulk metal and in early temperature steps, when compared to relative abundances derived from lunar ilmenite 71501 by chemical etching, recently put forward as representing the abundance ratios in solar wind. Estimates of the contribution of solar energetic particles (SEP) to the originally implanted solar gases, derived from a basic interpretation of He and Ne isotopes, yield values of about 10%. Analysis of the Ar isotopes requires a minimum of 20% SEP, and Kr isotopes, using our preferred composition for solar wind Kr, yield a result that overlaps both these values. It is possible to reconcile the data from these gases if significant loss of solar wind Ar, Kr and presumably Xe has occurred relative to the SEP component, most likely by erosive processes that are mass independent, although mass-dependent losses (Ar greater than Kr greater than Xe) cannot be excluded. If such losses did occur, the SEP contribution to the solar implanted gases must have been no more than a few percent. Nitrogen is a mixture of indigenous meteoritic N, whose isotopic composition is inferred to be relatively light, and implanted solar N, which has probably undergone diffusive redistribution and fractionation. If the heavy noble gases have not undergone diffusive loss, then N/Ar in the solar wind can be inferred to be at least several times the accepted solar ratio. The solar wind N appears, even after correction for fractionation effects, to have a minimum

  9. Modelling of noble anaesthetic gases and high hydrostatic pressure effects in lipid bilayers.

    PubMed

    Moskovitz, Yevgeny; Yang, Hui

    2015-03-21

    Our objective was to study molecular processes that might be responsible for inert gas narcosis and high-pressure nervous syndrome. The classical molecular dynamics trajectories (200 ns) of dioleoylphosphatidylcholine (DOPC) bilayers simulated by the Berger force field were evaluated for water and the atomic distribution of noble gases around DOPC molecules in the pressure range of 1-1000 bar and at a temperature of 310 K. Xenon and argon have been tested as model gases for general anaesthetics, and neon has been investigated for distortions that are potentially responsible for neurological tremors in hyperbaric conditions. The analysis of stacked radial pair distribution functions of DOPC headgroup atoms revealed the explicit solvation potential of the gas molecules, which correlates with their dimensions. The orientational dynamics of water molecules at the biomolecular interface should be considered as an influential factor, while excessive solvation effects appearing in the lumen of membrane-embedded ion channels could be a possible cause of inert gas narcosis. All the noble gases tested exhibit similar order parameter patterns for both DOPC acyl chains, which are opposite of the patterns found for the order parameter curve at high hydrostatic pressures in intact bilayers. This finding supports the 'critical volume' hypothesis of anaesthesia pressure reversal. The irregular lipid headgroup-water boundary observed in DOPC bilayers saturated with neon in the pressure range of 1-100 bar could be associated with the possible manifestation of neurological tremors at the atomic scale. The non-immobiliser neon also demonstrated the highest momentum impact on the normal component of the DOPC diffusion coefficient representing the monolayer undulation rate, which indicates that enhanced diffusivity rather than atomic size is the key factor.

  10. Modelling of noble anaesthetic gases and high hydrostatic pressure effects in lipid bilayers

    SciTech Connect

    Moskovitz, Yevgeny; Yang, Hui

    2015-01-08

    Our objective was to study molecular processes that might be responsible for inert gas narcosis and high-pressure nervous syndrome. The classical molecular dynamics trajectories (200 ns-long) of dioleoylphosphatidylcholine (DOPC) bilayers simulated by the Berger force field were evaluated for water and the atomic distribution of noble gases around DOPC molecules at a pressure range of 1 - 1000 bar and temperature of 310 Kelvin. Xenon and argon have been tested as model gases for general anesthetics, and neon has been investigated for distortions that are potentially responsible for neurological tremor at hyperbaric conditions. The analysis of stacked radial pair distribution functions of DOPC headgroup atoms revealed the explicit solvation potential of gas molecules, which correlates with their dimensions. The orientational dynamics of water molecules at the biomolecular interface should be considered as an influential factor; while excessive solvation effects appearing in the lumen of membrane-embedded ion channels could be a possible cause of inert gas narcosis. All the noble gases tested exhibit similar patterns of the order parameter for both DOPC acyl chains, which is opposite to the patterns found for the order parameter curve at high hydrostatic pressures in intact bilayers. This finding supports the ‘critical volume’ hypothesis of anesthesia pressure reversal. The irregular lipid headgroup-water boundary observed in DOPC bilayers saturated with neon in the pressure range of 1 - 100 bar could be associated with the possible manifestation of neurological tremor at the atomic scale. The non-immobilizer neon also demonstrated the highest momentum impact on the normal component of the DOPC diffusion coefficient representing monolayers undulations rate, which indicates enhanced diffusivity, rather than atom size, as the key factor.

  11. Modelling of noble anaesthetic gases and high hydrostatic pressure effects in lipid bilayers

    DOE PAGES

    Moskovitz, Yevgeny; Yang, Hui

    2015-01-08

    Our objective was to study molecular processes that might be responsible for inert gas narcosis and high-pressure nervous syndrome. The classical molecular dynamics trajectories (200 ns-long) of dioleoylphosphatidylcholine (DOPC) bilayers simulated by the Berger force field were evaluated for water and the atomic distribution of noble gases around DOPC molecules at a pressure range of 1 - 1000 bar and temperature of 310 Kelvin. Xenon and argon have been tested as model gases for general anesthetics, and neon has been investigated for distortions that are potentially responsible for neurological tremor at hyperbaric conditions. The analysis of stacked radial pair distributionmore » functions of DOPC headgroup atoms revealed the explicit solvation potential of gas molecules, which correlates with their dimensions. The orientational dynamics of water molecules at the biomolecular interface should be considered as an influential factor; while excessive solvation effects appearing in the lumen of membrane-embedded ion channels could be a possible cause of inert gas narcosis. All the noble gases tested exhibit similar patterns of the order parameter for both DOPC acyl chains, which is opposite to the patterns found for the order parameter curve at high hydrostatic pressures in intact bilayers. This finding supports the ‘critical volume’ hypothesis of anesthesia pressure reversal. The irregular lipid headgroup-water boundary observed in DOPC bilayers saturated with neon in the pressure range of 1 - 100 bar could be associated with the possible manifestation of neurological tremor at the atomic scale. The non-immobilizer neon also demonstrated the highest momentum impact on the normal component of the DOPC diffusion coefficient representing monolayers undulations rate, which indicates enhanced diffusivity, rather than atom size, as the key factor.« less

  12. The quest for regolithic howardites. Part 1: Two trends uncovered using noble gases

    NASA Astrophysics Data System (ADS)

    Cartwright, J. A.; Ott, U.; Mittlefehldt, D. W.; Herrin, J. S.; Herrmann, S.; Mertzman, S. A.; Mertzman, K. R.; Peng, Z. X.; Quinn, J. E.

    2013-03-01

    We report noble gas data (helium (He), neon (Ne), argon (Ar), krypton (Kr) and xenon (Xe)), nominal gas retention ages (K-Ar, U-Th-He) and cosmic ray exposure (CRE) ages for the ten howardites EET 83376, EET 99408, LEW 85313, MET 00423, MET 96500, PCA 02066, PRA 04401, QUE 94200, QUE 97002, and SCO 06040, in research to better understand the regolith of the HED parent body - Vesta - through a combined petrological, compositional and noble gas study. Our main aim is to determine which howardites are truly regolithic - as defined by the presence of solar noble gas components (e.g. solar wind (SW), fractionated solar wind (FSW)) and/or by the presence of planetary components (e.g. Q, HL) associated with foreign clasts of carbonaceous chondrite material within the breccias. Of our ten howardites, four (LEW 85313, MET 00423, PRA 04401 and SCO 06040) show evidence for a regolithic origin, with noble gas ratios indicating the presence of trapped components. Howardites PRA 04401 and SCO 06040 contain significant amounts of CM type carbonaceous chondrite material, and these samples are dominated by a planetary component similar to that observed in CM meteorites Murchison and Maribo. Overall, we find evidence for two regolithic groups with different release trends: (1) SW/FSW component dominated howardites (LEW 85313 and MET 00423), where SW/FSW is dominant at low temperature releases, and less pronounced at higher temperatures; (2) Planetary component dominated howardites (PRA 04401 and SCO 06040) that also contain SW/FSW - the planetary component is associated with incorporated carbonaceous chondrite material, and is dominant at the mid-temperature release. The remaining six howardites EET 83376, EET 99408, MET 96500, PCA 02066, QUE 94200, and QUE 97002, are dominated by cosmogenic noble gases, and are not considered regolithic. Previous work by Warren et al. (2009) suggested that high siderophile element contents (specifically nickel (Ni) > 300 μg/g) were a regolith

  13. Trapping of xenon in ice - Implications for the origin of the earth's noble gases

    NASA Technical Reports Server (NTRS)

    Wacker, J. F.; Anders, E.

    1984-01-01

    Although the earth's atmosphere contains Ne, Ar, and Kr in about C1,2-chondrite proportions, Xe is depleted about 20-fold. To test the suggestion that the 'missing' Xe is trapped in Antarctic ice, distribution coefficients for Xe in artifically formed frost at -20 to -60 C were measured, using Xe-127 tracer. The values are 0.098 + or - 0.004 cc STP/g atm for trapping and less than 5 cc STP/g atm for trapping plus adsorption. If these results are representative of natural ice, then the Antarctic ice cap contains less than 1 percent of the atmospheric Xe inventory, or not greater than about 0.001 the amount needed for a C1,2-chondrite pattern. Two possibilities remain for the 'missing' Xe, both on the premise that the earth's noble gases, along with other volatiles, came from chondritic material: (1) xenon is preferentially retained in the mantle and lower crust, due to the strong affinity of Xe for clean silicate surfaces and amorphous carbon; and (2) the source material of the earth's volatiles had high, relatively unfractionated, Ar/Xe and Kr/Xe ratios, like the non-carbonaceous noble gas carriers in C3O and E-chondrites.

  14. Estimating the recharge properties of the deep ocean using noble gases and helium isotopes

    NASA Astrophysics Data System (ADS)

    Loose, Brice; Jenkins, William J.; Moriarty, Roisin; Brown, Peter; Jullion, Loic; Naveira Garabato, Alberto C.; Torres Valdes, Sinhue; Hoppema, Mario; Ballentine, Chris; Meredith, Michael P.

    2016-08-01

    The distribution of noble gases and helium isotopes in the dense shelf waters of Antarctica reflects the boundary conditions near the ocean surface: air-sea exchange, sea ice formation, and subsurface ice melt. We use a nonlinear least squares solution to determine the value of the recharge temperature and salinity, as well as the excess air injection and glacial meltwater content throughout the water column and in the precursor to Antarctic Bottom Water. The noble gas-derived recharge temperature and salinity in the Weddell Gyre are -1.95°C and 34.95 psu near 5500 m; these cold, salty recharge values are a result of surface cooling as well as brine rejection during sea ice formation in Antarctic polynyas. In comparison, the global value for deep water recharge temperature is -0.44°C at 5500 m, which is 1.5°C warmer than the southern hemisphere deep water recharge temperature, reflecting a distinct contribution from the north Atlantic. The contrast between northern and southern hemisphere recharge properties highlights the impact of sea ice formation on setting the gas properties in southern sourced deep water. Below 1000 m, glacial meltwater averages 3.5‰ by volume and represents greater than 50% of the excess neon and argon found in the water column. These results indicate glacial melt has a nonnegligible impact on the atmospheric gas content of Antarctic Bottom Water.

  15. Trapping of Noble Gases by Radiative Association with H3 + in the Protosolar Nebula

    NASA Astrophysics Data System (ADS)

    Pauzat, F.; Bacchus-Montabonel, M.-C.; Ellinger, Y.; Mousis, O.

    2016-04-01

    The heavy noble gas deficiencies observed in Titan’s atmosphere and in comets have been proposed to be related to a sequestration process by {{{H}}}3+ in the gas phase at the early protosolar nebula. Chemical thermodynamics and astrophysics modeling are favorable to this hypothesis, as presented in preceding papers. However, there is a point still to be raised, i.e., that no dynamical study of the efficiency of the collisional processes had been performed so far. Here, we show that, apart from the expected exception of Ne, the rate constants obtained, i.e., 0.7 × 10-18, 0.5 × 10-16, and 10-16 (cm3 s-1) for Ar, Kr, and Xe, respectively, are reasonably high for such processes, particularly in the case of Kr and Xe. The temperature dependence is also considered, showing a similar behavior for all noble gases with a peak efficiency in the range 50-60 K. Globally, we can conclude that the scenario of sequestration by {{{H}}}3+ is definitively comforted by the results of our quantum dynamical treatment. This process may also be responsible of the Ar impoverishment just measured in comet 67P/Churyumov-Gerasimenko by the ROSINA mass spectrometer on board the Rosetta spacecraft.

  16. Impact of artificial recharge on dissolved noble gases in groundwater in California.

    PubMed

    Cey, Bradley D; Hudson, G Bryant; Moran, Jean E; Scanlon, Bridget R

    2008-02-15

    Dissolved noble gas concentrations in groundwater can provide valuable information on recharge temperatures and enable 3H-3He age-dating with the use of physically based interpretive models. This study presents a large (905 samples) data set of dissolved noble gas concentrations from drinking water supply wells throughout California, representing a range of physiographic, climatic, and water management conditions. Three common interpretive models (unfractionated air, UA; partial re-equilibration, PR; and closed system equilibrium, CE) produce systematically different recharge temperatures or ages; however, the ability of the different models to fit measured data within measurement uncertainty indicates that goodness-of-fit is not a robust indicator for model appropriateness. Therefore caution is necessary when interpreting model results. Samples from multiple locations contained significantly higher Ne and excess air concentrations than reported in the literature, with maximum excess air tending toward 0.05 cm3 STP g(-1) (deltaNe approximately 400%). Artificial recharge is the most plausible cause of the high excess air concentrations. The ability of artificial recharge to dissolve greater amounts of atmospheric gases has important implications for oxidation-reduction dependent chemical reactions. Measured gas concentration ratios suggest that diffusive degassing may have occurred. Understanding the physical processes controlling gas dissolution during groundwater recharge is critical for optimal management of artificial recharge and for predicting changes in water quality that can occur following artificial recharge.

  17. Atmospheric noble gases as tracers of biogenic gas dynamics in a shallow unconfined aquifer

    NASA Astrophysics Data System (ADS)

    Jones, Katherine L.; Lindsay, Matthew B. J.; Kipfer, Rolf; Mayer, K. Ulrich

    2014-03-01

    Atmospheric noble gases (NGs) were used to investigate biogenic gas dynamics in a shallow unconfined aquifer impacted by a crude oil spill, near Bemidji, MN. Concentrations of 3,4He, 20,22Ne, 36,40Ar, Kr, and Xe were determined for gas- and aqueous-phase samples collected from the vadose and saturated zones, respectively. Systematic elemental fractionation of Ne, Ar, Kr, and Xe with respect to air was observed in both of these hydrogeologic zones. Within the vadose zone, relative ratios of Ne and Ar to Kr and Xe revealed distinct process-related trends when compared to corresponding ratios for air. The degree of NG deviation from atmospheric concentrations generally increased with greater atomic mass (i.e., ΔXe > ΔKr > ΔAr > ΔNe), indicating that Kr and Xe are the most sensitive NG tracers in the vadose zone. Reactive transport modeling of the gas data confirms that elemental fractionation can be explained by mass-dependent variations in diffusive fluxes of NGs opposite to a total pressure gradient established between different biogeochemical process zones. Depletion of atmospheric NGs was also observed within a methanogenic zone of petroleum hydrocarbon degradation located below the water table. Solubility normalized NG abundances followed the order Xe > Kr > Ar > Ne, which is indicative of dissolved NG partitioning into the gas phase in response to bubble formation and possibly ebullition. Observed elemental NG ratios of Ne/Kr, Ne/Xe, Ar/Xe, and Kr/Xe and a modeling analysis provide strong evidence that CH4 generation below the water table caused gas exsolution and possibly ebullition and carbon transfer from groundwater to the vadose zone. These results suggest that noble gases provide sensitive tracers in biologically active unconfined aquifers and can assist in identifying carbon cycling and transfer within the vadose zone, the capillary fringe, and below the water table.

  18. Determination of Two-Photon Absorption Cross-Section of Noble Gases for Calibration of Laser Spectroscopic Techniques

    SciTech Connect

    Rosa, M. I. de la; Perez, C.; Gruetzmacher, K.; Fuentes, L. M.

    2008-10-22

    The objective of our work is to apply two-photon polarization spectroscopy as a new calibration method for the determination of two-photon excitation cross-sections of noble gases, like Xe and Kr, which are commonly used for calibrations of MP-LIF techniques in other laboratories.

  19. A Complex Exposure History of the Gold Basin L4-Chondrite Shower from Cosmogenic Radionuclides and Noble Gases

    NASA Technical Reports Server (NTRS)

    Welten, K. C.; Nishiizumi, K.; Caffee, M. W.; Masarik, J.; Wieler, R.

    2001-01-01

    Cosmogenic radionuclides and noble gases in samples of the Gold Basin L-chondrite shower indicate a complex exposure history, with a first stage exposure on the parent body, followed by a second stage of approx. 19 Myr in a meteoroid 3-4 m in radius. Additional information is contained in the original extended abstract.

  20. Crustal Noble Gases in Jwaneng Diamonds With Links to Seismic Tomography

    NASA Astrophysics Data System (ADS)

    Honda, M.; Phillips, D.; Harris, J. W.; Yatsevich, I.

    2005-12-01

    Recent seismic tomography studies of the Kaapvaal-Zimbabwe craton of southern Africa reveal distinct seismic velocity profiles at 150 km depth within the diamond stability field, that appear to correlate with differences in diamond paragenesis. Diamond mines with predominantly eclogitic diamond inclusions (e.g. Jwaneng, Orapa, Premier) overlie lithospheric mantle with relatively slow P-wave velocities, whereas localities with predominantly peridotitic diamond inclusions (e.g. Kimberley, Finsch) are associated with faster P-wave velocities at 150 km depth in the mantle. This distinction in P-wave velocities between the two groups can be interpreted in terms of different chemical compositions in the lithospheric mantle (Shirey, S. B. et al., Science 297, 1683-1686, 2002). Thus, the region with slower P-wave velocities could correlate with an oceanic lithospheric component and/or metasomatising fluids introduced by ancient subduction-related processes. In contrast, the region with faster P-wave velocities may reflect mid-Archean mantle depletion events initiated by craton keel formation. As the mantle beneath the Jwaneng mine is characterized by slower P-wave velocities at 150 km depth, our finding of crustal noble gases in Jwaneng diamonds (gem-quality diamond aggregates, this work; and framesites, Honda, M. et al., Chemical Geology 203, 347-358, 2004) appears to be consistent with the tomographic observations. It is noteworthy that early helium work on diamonds from the Orapa mine also showed radiogenic He-enriched 3He/4He ratios, as low as 0.16 R/Ra (Kurz, M. et al., Earth Planet. Sci. Lett. 86, 57-68, 1987), which could indicate the involvement of crustal helium; consistent with our findings from the Jwaneng diamonds. Thus, it is postulated that diamonds from eclogitic mines could clarify whether or not material subducted into the deep mantle retained crustal and atmospheric noble gases, and could quantify the influence of subducted material through time. In

  1. Are the C delta light nitrogen and noble gases located in the same carrier?

    NASA Technical Reports Server (NTRS)

    Verchovsky, A. B.; Russell, S. S.; Pillinger, C. T.; Fisenko, A. V.; Shukolyukov, Yuri A.

    1993-01-01

    Light nitrogen and the HL family noble gas components of C(sub delta) appear to be separable by high resolution pyrolysis experiments. Thus C(sub delta) is not a homogeneous material and probably consists of debris of many stars. The question of whether the N and Xe(HL) actually reside in different carriers continues to be addressed. It is well known that C(sub delta) which was identified as nanometer sized diamonds contains isotopically anamalous elements, in particular noble gases including Xe(HL) and its family and light nitrogen (delta(N-15) down to -350 percent). Before the true nature of C(sub delta) was recognized, it was easy to suppose that the Xe(HL) and light nitrogen were located in the same carrier. However, recognition that light nitrogen in diamond from different samples varies by greater than a factor of six compared to Xe(HL) fluctuations of ca. 20 percent makes such an assumption questionable. On the basis of simple arithmetic logic, the Xe and nitrogen cannot be absolutely co-located. The average diamond grain consists of only about 1000-2000 atoms of carbon; one grain among a few x 10(exp 6) contains an atom of Xe(HL) while 5-30 atoms of light nitrogen are the typical number which need to be in every diamond grain to account for observed concentrations. If some grains are devoid of N, the others have to have a higher N concentration. Even if we were able to analyze an individual grain of the diamond for noble gases and nitrogen, we would be faced with the monumental task of locating the one amongst 10(exp 6) identical grains containing the Xe atom to examine its nitrogen content. The problem can be simplified to some extent if instead of Xe, He which is 10(exp 4) times more abundant is assumed to be a member of the HL family. Attempts to fractionate the separate carriers might be attempted using He and N as guiding indicators but even experiments of this nature are for the future. Faced with apparently insoluble problems, we have returned to an

  2. Noble gases in the Oceanic Crust: Preliminary results from ODP Hole 1256D

    NASA Astrophysics Data System (ADS)

    Kurz, M. D.; Curtice, J. M.; IODP Expedition 335 Science Party

    2011-12-01

    Noble gas isotopes and abundance ratios have been extensively used as tracers of oceanic mantle sources and fluxes. Most of the existing data are from seafloor basalt glasses and hydrothermal fluids, and there are very few studies of noble gases in the oceanic crust, which is an important component in global subduction flux estimates. In an effort to determine the relative contributions of mantle, radiogenic, and atmospheric/hydrothermal noble gas components in the ocean crust, we have performed helium, neon and argon measurements on a suite of gabbros and granoblastic dikes collected during IODP Expeditions 312 and 335 to Hole 1256D, a deep crustal borehole drilled into 15 Ma ocean crust formed at the East Pacific Rise during an episode of superfast spreading (>200 mm/yr). All measurements were carried out by coupled vacuum crushing and melting of whole rock samples, in order to determine the distribution of noble gases within the ocean crust. Total helium abundances in the gabbros range from 0.46 to 1.22 micro cc STP/gram, which is 2 to 5 times higher than literature data, all of which are from the slow spreading Southwest Indian Ridge (Kumagai et al., 2003; Moreira et al., 2003). These strikingly higher helium concentrations place constraints on the thermal crustal history (due to rapid helium diffusivity) and are assumed to reflect fundamentally different emplacement/degassing processes within crust formed at a super fast spreading rate. Crushing releases 12-25 % of the total helium in the gabbros demonstrating that most of the helium resides in the solid mineral phases. Contact metamorphosed granoblastic dikes have total helium contents lower than the gabbros (typically ~ 0.15 micro cc STP/gram), but significantly higher than the assumed degassed basaltic protolith, thus suggesting that metamorphism actually adds helium to the crust, an important hypothesis that requires further testing. The helium isotopes obtained by crushing of both the gabbros and

  3. Lunar Meteorite QUE 93069: History Derived from Cosmic-Ray-Produced and Trapped Noble Gases

    NASA Astrophysics Data System (ADS)

    Thalmann, Ch.; Eugster, O.

    1995-09-01

    We obtained lunar meteorite QUE 93069,7 (0.304 g) from the NASA/MWG for the determination of its noble gas isotopic abundances and exposure history. The data relevant for the discussion of the exposure history and trapped noble gases are given in Tables 1 and 2. Exposure history: The duration of Moon-Earth transfer was determined by Nishiizumi et al. [1]. Based on 10Be these authors obtained 1.9 +/- 0.4 Ma for a 4 pi model (all radionuclides produced in 4 pi space) and <0.1 Ma for a 2 pi model (most radionuclides produced on the Moon). Adopting these times we find that less than one percent of the cosmogenic noble gases were produced during Moon- Earth transfer. The overwhelming amounts of 21Nec and 38Arc must have been produced during residence in the lunar regolith. Using lunar regolith production rates [2] at 5-10 g/cm2 shielding [1], we calculated the exposure times, T (2 pi), on the Moon. Table 2 gives the results and compares them with the exposure times for other anorthositic lunar meteorites (MAC 88105 and ALHA 81005). QUE 93069 shows the longest exposure to cosmic rays (1100 +/- 400 Ma) of all lunar meteorites if we compare the T38 values. Based on 21Nec we obtain 420 +/- 60 Ma. Typically for lunar surface material the T21 are lower than those based on 38Arc, 83Krc, and 126Xec due to 21Ne loss. This effect is also observed for MAC 88105 and ALHA 81005. Characteristics of the trapped noble gases: The long lunar surface residence time and the shallow shielding depth are consistent with the very large amounts of trapped solar wind particles (20Ne and 36Ar, Table 1) for QUE 93069. The concentration of trapped 36Ar is quite similar to that of Y-791197: Takaoka [3] and Ostertag et al. [4] obtained 33900 and 36600 x 10-8 cm3 STP/g, respectively. The trapped ratio 40Ar/36Ar, an antiquity indicator for lunar soil, yields information on the time when the breccia was compacted from regolith material [5]. For QUE 93069 we obtain (40Ar/36Ar)trapped = 1.9 +/- 0

  4. Regularities And Irregularities Of The Stark Parameters For Single Ionized Noble Gases

    NASA Astrophysics Data System (ADS)

    Peláez, R. J.; Djurovic, S.; Cirišan, M.; Aparicio, J. A.; Mar S.

    2010-07-01

    Spectroscopy of ionized noble gases has a great importance for the laboratory and astrophysical plasmas. Generally, spectra of inert gases are important for many physics areas, for example laser physics, fusion diagnostics, photoelectron spectroscopy, collision physics, astrophysics etc. Stark halfwidths as well as shifts of spectral lines are usually employed for plasma diagnostic purposes. For example atomic data of argon krypton and xenon will be useful for the spectral diagnostic of ITER. In addition, the software used for stellar atmosphere simulation like TMAP, and SMART require a large amount of atomic and spectroscopic data. Availability of these parameters will be useful for a further development of stellar atmosphere and evolution models. Stark parameters data of spectral lines can also be useful for verification of theoretical calculations and investigation of regularities and systematic trends of these parameters within a multiplet, supermultiplet or transition array. In the last years, different trends and regularities of Stark parameters (halwidths and shifts of spectral lines) have been analyzed. The conditions related with atomic structure of the element as well as plasma conditions are responsible for regular or irregular behaviors of the Stark parameters. The absence of very close perturbing levels makes Ne II as a good candidate for analysis of the regularities. Other two considered elements Kr II and Xe II with complex spectra present strong perturbations and in some cases an irregularities in Stark parameters appear. In this work we analyze the influence of the perturbations to Stark parameters within the multiplets.

  5. CANCELLED Molecular dynamics simulations of noble gases in liquidwater: Solvati on structure, self-diffusion, and kinetic isotopeeffect

    SciTech Connect

    Bourg, I.C.; Sposito, G.

    2007-05-25

    Despite their great importance in low-temperaturegeochemistry, self-diffusion coefficients of noble gas isotopes in liquidwater (D) have been measured only for the major isotopes of helium, neon,krypton and xenon. Data on the self-diffusion coefficients of minor noblegas isotopes are essentially non-existent and so typically are estimatedby a kinetic theory model in which D varies as the inverse square root ofthe isotopic mass (m): D proportional to m-0.5. To examine the validityof the kinetic theory model, we performed molecular dynamics (MD)simulations of the diffusion of noble gases in ambient liquid water withan accurate set of noble gas-water interaction potentials. Our simulationresults agree with available experimental data on the solvation structureand self-diffusion coefficients of the major noble gas isotopes in liquidwater and reveal for the first time that the isotopic mass-dependence ofall noble gas self-diffusion coefficients has the power-law form Dproportional to m-beta with 0noble gasisotopes caused by diffusion in ambient liquid water.

  6. Neuroprotection (and lack of neuroprotection) afforded by a series of noble gases in an in vitro model of neuronal injury.

    PubMed

    Jawad, Noorulhuda; Rizvi, Maleeha; Gu, Jianteng; Adeyi, Olar; Tao, Guocai; Maze, Mervyn; Ma, Daqing

    2009-09-04

    Xenon-induced neuroprotection has been well studied both in vivo and in vitro. In this study, the neuroprotective properties of the other noble gases, namely, krypton, argon, neon and helium, were explored in an in vitro model of neuronal injury. Pure neuronal cultures, derived from foetal BALB/c mice cortices, were provoked into injury by oxygen and glucose deprivation (OGD). Cultures were exposed to either nitrogen hypoxia or noble gas hypoxia in balanced salt solution devoid of glucose for 90min. The cultures were allowed to recover in normal culture medium for a further 24h in nitrogen or noble gas. The effect of noble gases on cell reducing ability in the absence of OGD was also investigated. Cell reducing ability was quantified via an MTT assay and expressed as a ratio of the control. The OGD caused a reduction in cell reducing ability to 0.56+/-0.04 of the control in the absence of noble gas (p<0.001). Like xenon (0.92+/-0.10; p<0.001), neuroprotection was afforded by argon (0.71+/-0.05; p<0.01). Neon and krypton did not have a protective effect under our experimental conditions. Helium had a detrimental effect on the cells. In the absence of OGD, krypton reduced the reducing ability of uninjured cells to 0.84+/-0.09 (p<0.01), but argon showed an improvement in reducing ability to 1.15+/-0.11 (p<0.05). Our data suggest that the cheap and widely available noble gas argon may have potential as a neuroprotectant for the future.

  7. Determining the source and genetic fingerprint of natural gases using noble gas geochemistry: a northern Appalachian Basin case study

    USGS Publications Warehouse

    Hunt, Andrew G.; Darrah, Thomas H.; Poreda, Robert J.

    2012-01-01

    Silurian and Devonian natural gas reservoirs present within New York state represent an example of unconventional gas accumulations within the northern Appalachian Basin. These unconventional energy resources, previously thought to be noneconomically viable, have come into play following advances in drilling (i.e., horizontal drilling) and extraction (i.e., hydraulic fracturing) capabilities. Therefore, efforts to understand these and other domestic and global natural gas reserves have recently increased. The suspicion of fugitive mass migration issues within current Appalachian production fields has catalyzed the need to develop a greater understanding of the genetic grouping (source) and migrational history of natural gases in this area. We introduce new noble gas data in the context of published hydrocarbon carbon (C1,C2+) (13C) data to explore the genesis of thermogenic gases in the Appalachian Basin. This study includes natural gases from two distinct genetic groups: group 1, Upper Devonian (Marcellus shale and Canadaway Group) gases generated in situ, characterized by early mature (13C[C1  C2][13C113C2]: –9), isotopically light methane, with low (4He) (average, 1  103 cc/cc) elevated 4He/40Ar and 21Ne/40Ar (where the asterisk denotes excess radiogenic or nucleogenic production beyond the atmospheric ratio), and a variable, atmospherically (air-saturated–water) derived noble gas component; and group 2, a migratory natural gas that emanated from Lower Ordovician source rocks (i.e., most likely, Middle Ordovician Trenton or Black River group) that is currently hosted primarily in Lower Silurian sands (i.e., Medina or Clinton group) characterized by isotopically heavy, mature methane (13C[C1 – C2] [13C113C2]: 3), with high (4He) (average, 1.85  103 cc/cc) 4He/40Ar and 21Ne/40Ar near crustal production levels and elevated crustal noble gas content (enriched 4He,21Ne, 40Ar). Because the release of each crustal noble gas (i.e., He, Ne, Ar

  8. Isotopic Composition of Trapped and Cosmogenic Noble Gases in Several Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Garrison, Daniel H.; Bogard, Donald D.

    1997-01-01

    Isotopic abundances of the noble gases were measured in the following Martian meteorites: two shock glass inclusions from EET79001, shock vein glass from Shergotty and Y793605, and whole rock samples of ALH84001 and QUE94201. These glass samples, when combined with literature data on a separate single glass inclusion from EET79001 and a glass vein from Zagami, permit examination of the isotopic composition of Ne, Ar, Kr, and Xe trapped from the Martian atmosphere in greater detail. The isotopic composition of Martian Ne, if actually present in these glasses, remains poorly defined. The Ar-40/Ar-36 ratio of Martian atmospheric Ar may be much less than the ratio measured by Viking and possibly as low as approx. 1900. The atmospheric Ar-36/Ar-38 ratio is less than or equal to 4.0. Martian atmospheric Kr appears to be enriched in lighter isotopes by approx. 0.4%/amu compared to both solar wind Kr and to the Martian composition previously reported. The Martian atmospheric Ar-36/Xe-132 and Kr-84/Xe-132 Xe elemental ratios are higher than those reported by Viking by factors of approx. 3.3 and approx. 2.5, respectively. Cosmogenic gases indicate space exposure ages of 13.9 +/- 1 Myr for ALH84001 and 2.7 +/- 0.6 Myr for QUE94201. Small amounts of Ne-21 produced by energetic solar protons may be present in QUE94201, but are not present in ALH84001 or Y793605. The space exposure age for Y793605 is 4.9 +/- 0.6 Myr and appears to be distinctly older than the ages for basaltic shergottites.

  9. Noble Gases in the Lunar Meteorites Calcalong Creek and QUE 93069

    NASA Astrophysics Data System (ADS)

    Swindle, T. D.; Burkland, M. K.; Grier, J. A.

    1995-09-01

    Although the world's collections contain comparable numbers of martian and lunar meteorites (about 10 each), their ejection histories seem to be quite different [1]. We have sampled no more than four martian craters, but almost every one of the lunar meteorites apparently represents a separate cratering event. Furthermore, most lunar meteorites were apparently ejected from the top meter of the surface, unlike any of the martian meteorites. We have measured noble gases in two bulk samples of the lunar meteorite QUE93069 and three of Calcalong Creek, ranging in size from 7 to 15 mg. Averaged results are given in Table 1. Both meteorites contain solar-wind-implanted noble gas. QUE 93069, which is a mature anorthositic regolith breccia [2], contains amounts comparable to the most gas-rich lunar meteorites. The relatively low 40Ar/36Ar ratios of both meteorites suggest surface exposures no more than 2.5 Ga ago [3]. Calcalong Creek has readily observable spallogenic gas. The 131Xe/126Xe ratio of 4.8+/-0.3 corresponds to an average shielding depth of slightly more than 40 gm/cm^2 [4]. In common with many lunar breccias, Calcalong Creek has been exposed to cosmic rays for several hundred Ma (calculations based on [4] and [5]). The 3He apparent exposure age is much shorter, suggesting diffusive loss of He. To determine the detailed exposure history, it is necessary to have measurements of cosmogenic radionuclides. Our samples were too small to measure 81Kr, but [6] have measured 10Be, 26Al and 36Cl. Their data are consistent with either extended exposure at <70 gm/cm^2 in the lunar regolith followed by a short (200,000 years) transit to Earth, or with ejection from several meters depth about 2 Ma ago [6]. Our data, requiring several hundred Ma of exposure at an average depth of 40-50 gm/cm^2, are clearly more consistent with the first scenario. The only other lunar meteorite which could have been ejected at the same time is MAC 88104/5 [1], but the chemical differences

  10. Optimized Mie potentials for phase equilibria: Application to noble gases and their mixtures with n-alkanes.

    PubMed

    Mick, Jason R; Soroush Barhaghi, Mohammad; Jackman, Brock; Rushaidat, Kamel; Schwiebert, Loren; Potoff, Jeffrey J

    2015-09-21

    Transferrable force fields, based on n-6 Mie potentials, are presented for noble gases. By tuning the repulsive exponent, ni, it is possible to simultaneously reproduce experimental saturated liquid densities and vapor pressures with high accuracy, from the normal boiling point to the critical point. Vapor-liquid coexistence curves for pure fluids are calculated using histogram reweighting Monte Carlo simulations in the grand canonical ensemble. For all noble gases, saturated liquid densities and vapor pressures are reproduced to within 1% and 4% of experiment, respectively. Radial distribution functions, extracted from NVT and NPT Monte Carlo simulations, are in similarly excellent agreement with experimental data. The transferability of the optimized force fields is assessed through calculations of binary mixture vapor-liquid equilibria. These mixtures include argon + krypton, krypton + xenon, methane + krypton, methane + xenon, krypton + ethane, and xenon + ethane. For all mixtures, excellent agreement with experiment is achieved without the introduction of any binary interaction parameters or multi-body interactions.

  11. Slab-derived halogens and noble gases illuminate closed system processes controlling volatile element transport into the mantle wedge

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masahiro; Sumino, Hirochika; Nagao, Keisuke; Ishimaru, Satoko; Arai, Shoji; Yoshikawa, Masako; Kawamoto, Tatsuhiko; Kumagai, Yoshitaka; Kobayashi, Tetsuo; Burgess, Ray; Ballentine, Chris J.

    2017-01-01

    Halogen and noble gas systematics are powerful tracers of volatile recycling in subduction zones. We present halogen and noble gas compositions of mantle peridotites containing H2O-rich fluid inclusions collected at volcanic fronts from two contrasting subduction zones (the Avacha volcano of Kamchatka arc and the Pinatubo volcano of Luzon arcs) and orogenic peridotites from a peridotite massif (the Horoman massif, Hokkaido, Japan) which represents an exhumed portion of the mantle wedge. The aims are to determine how volatiles are carried into the mantle wedge and how the subducted fluids modify halogen and noble gas compositions in the mantle. The halogen and noble gas signatures in the H2O-rich fluids are similar to those of marine sedimentary pore fluids and forearc and seafloor serpentinites. This suggests that marine pore fluids in deep-sea sediments are carried by serpentine and supplied to the mantle wedge, preserving their original halogen and noble gas compositions. We suggest that the sedimentary pore fluid-derived water is incorporated into serpentine through hydration in a closed system along faults at the outer rise of the oceanic, preserving Cl/H2O and 36Ar/H2O values of sedimentary pore fluids. Dehydration-hydration process within the oceanic lithospheric mantle maintains the closed system until the final stage of serpentine dehydration. The sedimentary pore fluid-like halogen and noble gas signatures in fluids released at the final stage of serpentine dehydration are preserved due to highly channelized flow, whereas the original Cl/H2O and 36Ar/H2O ratios are fractionated by the higher incompatibility of halogens and noble gases in hydrous minerals.

  12. Pressure effects on the X-ray intrinsic position resolution in noble gases and mixtures

    NASA Astrophysics Data System (ADS)

    Azevedo, C. D. R.; González-Díaz, D.; Correia, P. M. M.; Biagi, S.; Silva, A. L. M.; Carramate, L. F. N. D.; Veloso, J. F. C. A.

    2016-12-01

    A study of the effect of gas pressure in the position resolution of an interacting X or γ-ray photon in a gas medium is performed. The intrinsic position resolution for pure noble gases (Argon and Xenon) and their mixtures with CO2 and CH4 was calculated for several gas pressures (1-10 bar) and for photon energies between 1 and 60 keV, being possible to establish a linear relation between the intrinsic position resolution and the inverse of the gas pressure in the indicated energy range, as intuitively expected. We show how, at high pressures and low photoelectron energies, this intrinsic 1/P scaling is modified due to the diffusion of the primary ionization in the direction perpendicular to the electric field. In order to evaluate the quality of the method here described, a comparison between the available experimental data and microscopic simulations is presented in this work and discussed. In the majority of cases, a good agreement is observed. The conditions to achieve position resolutions down to 10 μm in a realistic detector are shown and discussed.

  13. Analytical equation of state with three-body forces: Application to noble gases

    SciTech Connect

    Río, Fernando del Díaz-Herrera, Enrique; Guzmán, Orlando; Moreno-Razo, José Antonio; Ramos, J. Eloy

    2013-11-14

    We developed an explicit equation of state (EOS) for small non polar molecules by means of an effective two-body potential. The average effect of three-body forces was incorporated as a perturbation, which results in rescaled values for the parameters of the two-body potential. These values replace the original ones in the EOS corresponding to the two-body interaction. We applied this procedure to the heavier noble gases and used a modified Kihara function with an effective Axilrod-Teller-Muto (ATM) term to represent the two- and three-body forces. We also performed molecular dynamics simulations with two- and three-body forces. There was good agreement between predicted, simulated, and experimental thermodynamic properties of neon, argon, krypton, and xenon, up to twice the critical density and up to five times the critical temperature. In order to achieve 1% accuracy of the pressure at liquid densities, the EOS must incorporate the effect of ATM forces. The ATM factor in the rescaled two-body energy is most important at temperatures around and lower than the critical one. Nonetheless, the rescaling of two-body diameter cannot be neglected at liquid-like densities even at high temperature. This methodology can be extended straightforwardly to deal with other two- and three-body potentials. It could also be used for other nonpolar substances where a spherical two-body potential is still a reasonable coarse-grain approximation.

  14. Virial based equations of state with account of three-body interaction for noble gases and their mixtures

    NASA Astrophysics Data System (ADS)

    Akhmatov, Z. A.; Khokonov, A. Kh; Khokonov, M. Kh

    2016-11-01

    Within the frame of molecular dynamics the equations of state of noble gases and their mixtures have been obtained by means of time averaging procedure for virial based equation with account of three-body interaction. It has been shown, that equations of state can be extrapolated by van-der-Waals-type equations. The corresponding parameters have been calculated. A visible foliation of Xe and Kr components of Kob-Andersen mixture has been found.

  15. Measuring radioactive noble gases by absorption in polycarbonates and other organics: From radon indoors to nuclear safety

    NASA Astrophysics Data System (ADS)

    Pressyanov, Dobromir S.

    2013-07-01

    The report summarizes recent research and practice of using materials with high absorption ability to noble gases to measure their radioactive isotopes. Most of the studies employ bisphenol-A based polycarbonates, because of their remarkably high absorption ability to noble gases. This is the material of which commercial CDs/DVDs are made and they may serve as serendipitous, already available in dwellings, radon and thoron detectors. We present the essence of the gathered experimental evidence that the CD/DVD method can successfully address some long-lasted problems in radon dosimetry: The first is making sufficiently precise retrospective 222Rn dosimetry for the purposes of epidemiological studies and risk estimation. The second is rapid identification of buildings with radon problem. We demonstrate how this can be used to develop an integrated approach to the radon problem. Within this approach detection, diagnostic and mitigation are considered as an unified whole, and the interval between the decision to provide disks for analysis and the complete mitigation of the building, if radon problem is identified, is short. Besides radon and thoron, bisphenol-A based polycarbonates were successfully used to measure 85Kr and 133Xe for the purposes of the effluents control and nuclear safety of nuclear installations. The perspectives to employ other organic materials in which noble gases are highly soluble for measurement of their radioactive isotopes are also discussed.

  16. Santa Lucia (2008) (L6) Chondrite, a Recent Fall: Composition, Noble Gases, Nitrogen and Cosmic Ray Exposure Age

    NASA Astrophysics Data System (ADS)

    Mahajan, Ramakant R.; Varela, Maria Eugenia; Joron, Jean Louis

    2016-04-01

    The Santa Lucia (2008)—one the most recent Argentine meteorite fall, fell in San Juan province, Argentina, on 23 January 2008. Several masses (total ~6 kg) were recovered. Most are totally covered by fusion crust. The exposed interior is of light-grey colour. Chemical data [olivine (Fa24.4) and low-Ca pyroxene (En77.8 Fs20.7 Wo1.6)] indicate that Santa Luica (2008) is a member of the low iron L chondrite group, corresponding to the equilibrated petrologic type 6. The meteorite name was approved by the Nomenclature Committee (NomCom) of the Meteoritical Society (Meteoritic Bulletin, no. 97). We report about the chemical composition of the major mineral phases, its bulk trace element abundance, its noble gas and nitrogen data. The cosmic ray exposure age based on cosmogenic 3He, 21Ne, and 38Ar around 20 Ma is comparable to one peak of L chondrites. The radiogenic K-Ar age of 2.96 Ga, while the young U, Th-He are of 1.2 Ga indicates that Santa Lucia (2008) lost radiogenic 4He more recently. Low cosmogenic (22Ne/21Ne)c and absence of solar wind noble gases are consistent with irradiation in a large body. Heavy noble gases (Ar/Kr/Xe) indicated trapped gases similar to ordinary chondrites. Krypton and neon indicates irradiation in large body, implying large pre-atmospheric meteoroid.

  17. Noble gases, nitrogen, and methane from the deep interior to the atmosphere of Titan

    NASA Astrophysics Data System (ADS)

    Glein, Christopher R.

    2015-04-01

    Titan's thick N2-CH4 atmosphere is unlike any in the Solar System, and its origin has been shrouded in mystery for over half a century. Here, I perform a detailed analysis of chemical and isotopic data from the Cassini-Huygens mission to develop the hypothesis that Titan's (non-photochemical) atmospheric gases came from deep within. It is suggested that Titan's CH4, N2, and noble gases originated in a rocky core buried inside the giant satellite, and hydrothermal and cryovolcanic processes were critical to the creation of Titan's atmosphere. Mass balance and chemical equilibrium calculations demonstrate that all aspects of this hypothesis can be considered geochemically plausible with respect to contemporary observational, experimental, and theoretical knowledge. Specifically, I show that a rocky core with a bulk noble gas content similar to that in CI carbonaceous meteorites would contain sufficient 36Ar and 22Ne to explain their reported abundances. I also show that Henry's law constants for noble gases in relevant condensed phases can be correlated with the size of their atoms, which leads to expected mixing ratios for 84Kr (∼0.2 ppbv) and 132Xe (∼0.01 ppbv) that can explain why these species have yet to be detected (Huygens upper limit <10 ppbv). The outgassing of volatiles into Titan's atmosphere may be restricted by the stability of clathrate hydrates in Titan's interior. The noble gas geochemistry also provides significant new insights into the origin of N2 and CH4 on Titan, as I find that Ar and N2, and Kr and CH4 should exhibit similar phase partitioning behavior on Titan. One implication is that over 95% of Titan's N2 may still reside in the interior. Another key result is that the upper limit from the Huygens GC-MS on the Kr/CH4 ratio in Titan's atmosphere is far too low to be consistent with accretion of primordial CH4 clathrate, which motivates me to consider endogenic production of CH4 from CO2 as a result of geochemical reactions between liquid

  18. Noble gases preserve history of retentive continental crust in the Bravo Dome natural CO2 field, New Mexico

    NASA Astrophysics Data System (ADS)

    Sathaye, Kiran J.; Smye, Andrew J.; Jordan, Jacob S.; Hesse, Marc A.

    2016-06-01

    Budgets of 4He and 40Ar provide constraints on the chemical evolution of the solid Earth and atmosphere. Although continental crust accounts for the majority of 4He and 40Ar degassed from the Earth, degassing mechanisms are subject to scholarly debate. Here we provide a constraint on crustal degassing by comparing the noble gases accumulated in the Bravo Dome natural CO2 reservoir, New Mexico USA, with the radiogenic production in the underlying crust. A detailed geological model of the reservoir is used to provide absolute abundances and geostatistical uncertainty of 4He, 40Ar, 21Ne, 20Ne, 36Ar, and 84Kr. The present-day production rate of crustal radiogenic 4He and 40Ar, henceforth referred to as 4He* and 40Ar*, is estimated using the basement composition, surface and mantle heat flow, and seismic estimates of crustal density. After subtracting mantle and atmospheric contributions, the reservoir contains less than 0.02% of the radiogenic production in the underlying crust. This shows unequivocally that radiogenic noble gases are effectively retained in cratonic continental crust over millennial timescales. This also requires that approximately 1.5 Gt of mantle derived CO2 migrated through the crust without mobilizing the crustally accumulated gases. This observation suggests transport along a localized fracture network. Therefore, the retention of noble gases in stable crystalline continental crust allows shallow accumulations of radiogenic gases to record tectonic history. At Bravo Dome, the crustal 4He*/40Ar* ratio is one fifth of the expected crustal production ratio, recording the preferential release of 4He during the Ancestral Rocky Mountain orogeny, 300 Ma.

  19. Degassing of Noble Gases in Mid-Ocean Ridge and Ocean-Island Basalts: A Self- Consistent Model

    NASA Astrophysics Data System (ADS)

    Gonnermann, H. M.; Mukhopadhyay, S.

    2006-12-01

    We present results from numerical degassing models for H2O, CO2, He, Ne, and Ar during ascent-driven decompression of mid-ocean ridge basalts (MORBs) and ocean island basalts (OIBs). Degassing is modeled for a range of decompression rates, encompassing equilibrium through disequilibrium, and for open-system loss of exsolved gas ranging from 100% through 0% (closed-system). Our calculations predict the abundances and elemental ratios of noble gases dissolved in the melt during ascent to the sea floor. The resultant degassing trajectories are compared against measured volatiles in oceanic basalt glasses. We also calculate abundances and elemental ratios of the exsolved volatiles forming bubbles within the magma and compare them against measured values from crushed basalt glasses. From a comprehensive compilation of published analyses we find that concentrations and elemental ratios of CO2, He, Ne and Ar in MORB and OIB glasses are consistent with varying degrees of open-system degassing during magma ascent. Exsolution of He and Ne are primarily controlled by their solubilities. Because solubilities are dependent on fugacities via Henry's law, exsolution of He and Ne is dependent on the CO2 content of the magma. In contrast, Ar exsolution appears to be kinetically controlled, consistent with its relatively low diffusivity. CO2 and H2O concentrations of the modeled parental magma are within the range of observed values (1000 to 5000 ppm). We find that noble gases in MORBs are explained self-consistently by degassing of a parental magma with initial noble gas concentrations that fall within the range of values derived from hydrothermal 3He/CO2 ratios and measured values in popping rock 2ΠD43. Most OIBs are best explained by degassing of a parental magma with similar radiogenic and nucleogenic noble-gases, but an enrichment in primordial 3He and ^{22}Ne, relative to MORB.

  20. Extraction of Solar Wind Nitrogen and Noble Gases From the Genesis Gold Foil Collector

    NASA Astrophysics Data System (ADS)

    Schlutter, D. J.; Pepin, R. O.

    2005-12-01

    The Genesis gold foil is a bulk solar wind collector, integrating fluences from all three of the wind regimes. Pyrolytic extraction of small foil samples at Minnesota yielded He fluences, corrected for backscatter, in good agreement with measurements by on-board spacecraft instruments, and He/Ne elemental ratios close to those implanted in collector foils deployed on the lunar surface during the Apollo missions. Isotopic distributions of He, Ne and Ar are under study. Pyrolysis to temperatures above the gold melting point generates nitrogen blanks large enough to obscure the solar-wind nitrogen component. An alternative technique for nitrogen and noble gas extraction, by room-temperature amalgamation of the gold foil surface, will be discussed. Ne and Ar releases in preliminary tests of this technique on small foil samples were close to 100% of the amounts expected from the high-temperature pyrolysis yields, indicating that amalgamation quantitatively liberates gases from several hundred angstroms deep in the gold, beyond the implantation depth of most of the solar wind. Present work is focused on two problems currently interfering with accurate nitrogen measurements at the required picogram to sub-picogram levels: a higher than expected blank likely due to tiny air bubbles rolled into the gold sheet during fabrication, and the presence of a refractory hydrocarbon film on Genesis collector surfaces (the "brown stain") that, if left in place on the foil, shields the underlying gold from mercury attack. We have found, however, that the film is efficiently removed within tens of seconds by oxygen plasma ashing. Potential nitrogen contaminants introduced during the crash of the sample return canister are inert in amalgamation, and so are not hazards to the measurements.

  1. Noble gases identify the mechanisms of fugitive gas contamination in drinking-water wells overlying the Marcellus and Barnett Shales.

    PubMed

    Darrah, Thomas H; Vengosh, Avner; Jackson, Robert B; Warner, Nathaniel R; Poreda, Robert J

    2014-09-30

    Horizontal drilling and hydraulic fracturing have enhanced energy production but raised concerns about drinking-water contamination and other environmental impacts. Identifying the sources and mechanisms of contamination can help improve the environmental and economic sustainability of shale-gas extraction. We analyzed 113 and 20 samples from drinking-water wells overlying the Marcellus and Barnett Shales, respectively, examining hydrocarbon abundance and isotopic compositions (e.g., C2H6/CH4, δ(13)C-CH4) and providing, to our knowledge, the first comprehensive analyses of noble gases and their isotopes (e.g., (4)He, (20)Ne, (36)Ar) in groundwater near shale-gas wells. We addressed two questions. (i) Are elevated levels of hydrocarbon gases in drinking-water aquifers near gas wells natural or anthropogenic? (ii) If fugitive gas contamination exists, what mechanisms cause it? Against a backdrop of naturally occurring salt- and gas-rich groundwater, we identified eight discrete clusters of fugitive gas contamination, seven in Pennsylvania and one in Texas that showed increased contamination through time. Where fugitive gas contamination occurred, the relative proportions of thermogenic hydrocarbon gas (e.g., CH4, (4)He) were significantly higher (P < 0.01) and the proportions of atmospheric gases (air-saturated water; e.g., N2, (36)Ar) were significantly lower (P < 0.01) relative to background groundwater. Noble gas isotope and hydrocarbon data link four contamination clusters to gas leakage from intermediate-depth strata through failures of annulus cement, three to target production gases that seem to implicate faulty production casings, and one to an underground gas well failure. Noble gas data appear to rule out gas contamination by upward migration from depth through overlying geological strata triggered by horizontal drilling or hydraulic fracturing.

  2. Noble gases identify the mechanisms of fugitive gas contamination in drinking-water wells overlying the Marcellus and Barnett Shales

    PubMed Central

    Darrah, Thomas H.; Vengosh, Avner; Jackson, Robert B.; Warner, Nathaniel R.; Poreda, Robert J.

    2014-01-01

    Horizontal drilling and hydraulic fracturing have enhanced energy production but raised concerns about drinking-water contamination and other environmental impacts. Identifying the sources and mechanisms of contamination can help improve the environmental and economic sustainability of shale-gas extraction. We analyzed 113 and 20 samples from drinking-water wells overlying the Marcellus and Barnett Shales, respectively, examining hydrocarbon abundance and isotopic compositions (e.g., C2H6/CH4, δ13C-CH4) and providing, to our knowledge, the first comprehensive analyses of noble gases and their isotopes (e.g., 4He, 20Ne, 36Ar) in groundwater near shale-gas wells. We addressed two questions. (i) Are elevated levels of hydrocarbon gases in drinking-water aquifers near gas wells natural or anthropogenic? (ii) If fugitive gas contamination exists, what mechanisms cause it? Against a backdrop of naturally occurring salt- and gas-rich groundwater, we identified eight discrete clusters of fugitive gas contamination, seven in Pennsylvania and one in Texas that showed increased contamination through time. Where fugitive gas contamination occurred, the relative proportions of thermogenic hydrocarbon gas (e.g., CH4, 4He) were significantly higher (P < 0.01) and the proportions of atmospheric gases (air-saturated water; e.g., N2, 36Ar) were significantly lower (P < 0.01) relative to background groundwater. Noble gas isotope and hydrocarbon data link four contamination clusters to gas leakage from intermediate-depth strata through failures of annulus cement, three to target production gases that seem to implicate faulty production casings, and one to an underground gas well failure. Noble gas data appear to rule out gas contamination by upward migration from depth through overlying geological strata triggered by horizontal drilling or hydraulic fracturing. PMID:25225410

  3. H3(+) as a trap for noble gases-3: multiple trapping of neon, argon, and krypton in X(n)H3(+) (n = 1-3).

    PubMed

    Pauzat, F; Ellinger, Y; Pilmé, J; Mousis, O

    2009-05-07

    Recent studies on the formation of XH(3)(+) noble gas complexes have shown strategic implications for the composition of the atmospheres of the giant planets as well as for the composition of comets. One crucial factor in the astrophysical process is the relative abundances of the noble gases versus H(3)(+). It is the context in which the possibility for clustering with more than one noble gas (X(n)H(3)(+) up to n = 3) has been investigated for noble gases X ranging from neon to krypton. In order to assert our results, a variety of methods have been used including ab initio coupled cluster CCSD and CCSD(T), MP2, and density functional BH&HLYP levels of theory. All complexes with one, two, and three noble gases are found to be stable in the Ne, Ar, and Kr families. These stable structures are planar with the noble gases attached to the apices of the H(3)(+) triangle. The binding energy of the nth atom, defined as the X(n)H(3)(+) --> X(n-1)H(3)(+) + X reaction energy, increases slightly with n varying from 1 to 3 in the neon series, while it decreases in the argon series and shows a minimum for n = 2 in the krypton series. The origin of this phenomenon is to be found in the variations in the respective vibrational energies. A topological analysis of the electron localization function shows the importance of the charge transfer from the noble gases toward H(3)(+) as a driving force in the bonding along the series. It is also consistent with the increase in the atomic polarizabilities from neon to krypton. Rotational constants and harmonic frequencies are reported in order to provide a body of data to be used for the detection in laboratory prior to space observations. This study strongly suggests that the noble gases could be sequestered even in an environment where the H(3)(+) abundance is small.

  4. Noble gases in submarine pillow basalt glasses from Loihi and Kilauea, Hawaii: A solar component in the Earth

    USGS Publications Warehouse

    Honda, M.; McDougall, I.; Patterson, D.B.; Doulgeris, A.; Clague, D.A.

    1993-01-01

    Noble gas elemental and isotopic abundances have been analysed in twenty-two samples of basaltic glass dredged from the submarine flanks of two currently active Hawaiian volcanoes, Loihi Seamount and Kilauea. Neon isotopic ratios are enriched in 20Ne and 21Ne by as much as 16% with respect to atmospheric ratios. All the Hawaiian basalt glass samples show relatively high 3He 4He ratios. The high 20Ne 22Ne values in some of the Hawaiian samples, together with correlations between neon and helium systematics, suggest the presence of a solar component in the source regions of the Hawaiian mantle plume. The solar hypothesis for the Earth's primordial noble gas composition can account for helium and neon isotopic ratios observed in basaltic glasses from both plume and spreading systems, in fluids in continental hydrothermal systems, in CO2 well gases, and in ancient diamonds. These results provide new insights into the origin and evolution of the Earth's atmosphere. ?? 1993.

  5. Infiltration of river water to a shallow aquifer investigated with 3H/ 3He, noble gases and CFCs

    NASA Astrophysics Data System (ADS)

    Beyerle, U.; Aeschbach-Hertig, W.; Hofer, M.; Imboden, D. M.; Baur, H.; Kipfer, R.

    1999-09-01

    Noble gas isotopes ( 3He, 4He, Ne, Ar, Kr, Xe), tritium ( 3H), chlorofluorocarbons (CFCs) and dissolved oxygen (O 2) were seasonally measured in a small groundwater system recharged by infiltration of river water at Linsental, northeastern Switzerland. All Groundwater samples contained an excess of atmospheric noble gases ('excess air') usually with an elemental composition equal to air. The concentrations of atmospheric noble gases in the groundwater were used to calculate the excess air component and the water temperature at recharge. The noble gas temperatures (NGTs) in the boreholes close to the river vary seasonally, however, the average NGT of all samples lies close to the mean annual temperature of the river water. Groundwater ages were calculated using the tritium/helium-3 ( 3H/ 3He) dating method. The water ages of the samples obtained near the river depend on the amount of recently infiltrated river water and are young during times of active river discharge. In contrast, the mean water age of about 3 years of the deep aquifer remained nearly constant over the sampling period. The observed CFC-11 (CFCl 3) and CFC-12 (CF 2Cl 2) concentrations are significantly higher than the atmospheric equilibrium concentrations and therefore CFCs do not provide any direct information on the residence time of the groundwater. Nevertheless, the CFC excess in the groundwater shows a linear increase with the 3H/ 3He age. Additionally, both accumulation of radiogenic He ( 4He rad) and O 2 consumption are strongly correlated with residence time. All these correlations can be interpreted either in terms of mixing of recently infiltrated river water with older groundwater or in terms of accumulation/consumption rates.

  6. IMPACT REGIMES AND POST-FORMATION SEQUESTRATION PROCESSES: IMPLICATIONS FOR THE ORIGIN OF HEAVY NOBLE GASES IN TERRESTRIAL PLANETS

    SciTech Connect

    Mousis, Olivier; Petit, Jean-Marc; Picaud, Sylvain; Thomas, Caroline; Schmitt, Bernard

    2010-05-10

    The difference between the measured atmospheric abundances of neon, argon, krypton, and xenon for Venus, Earth, and Mars is striking. Because these abundances drop by at least 2 orders of magnitude as one moves outward from Venus to Mars, the study of the origin of this discrepancy is a key issue that must be explained if we are to fully understand the different delivery mechanisms of the volatiles accreted by the terrestrial planets. In this work, we aim to investigate whether it is possible to quantitatively explain the variation of the heavy noble gas abundances measured on Venus, Earth, and Mars, assuming that cometary bombardment was the main delivery mechanism of these noble gases to the terrestrial planets. To do so, we use recent dynamical simulations that allow the study of the impact fluxes of comets upon the terrestrial planets during the course of their formation and evolution. Assuming that the mass of noble gases delivered by comets is proportional to the rate at which they collide with the terrestrial planets, we show that the krypton and xenon abundances in Venus and Earth can be explained in a manner consistent with the hypothesis of cometary bombardment. In order to explain the krypton and xenon abundance differences between Earth and Mars, we need to invoke the presence of large amounts of CO{sub 2}-dominated clathrates in the Martian soil that would have efficiently sequestered these noble gases. Two different scenarios based on our model can also be used to explain the differences between the neon and argon abundances of the terrestrial planets. In the first scenario, cometary bombardment of these planets would have occurred at epochs contemporary with the existence of their primary atmospheres. Comets would have been the carriers of argon, krypton, and xenon, while neon would have been gravitationally captured by the terrestrial planets. In the second scenario, we consider impacting comets that contained significantly smaller amounts of argon

  7. Trapped solar wind noble gases, kr81/kr exposure ages and k/ar ages in apollo 11 lunar material.

    PubMed

    Eberhardt, P; Geiss, J; Graf, H; Grögler, N; Krähenbühl, U; Schwaller, H; Schwarzmüller, J; Stettler, A

    1970-01-30

    Grain size and etching experiments show that the fine lunar material contains large amounts of trapped solar wind particles. Elemental and isotopic compositions of the noble gases in solar material and in the terrestrial atmosphere are significantly different, except for the Ar(36)/ Ar(38) and the Kr isotope ratios. Exposure ages of two rocks and of the fine material are between 380 and 510 x 10(6) years. Feldspar concentrates give K/Ar ages of 3220 and 3300 x 10(6) years, significantly higher than the unseparated rock.

  8. Effect of residual gases in high vacuum on the energy-level alignment at noble metal/organic interfaces

    SciTech Connect

    Helander, M. G.; Wang, Z. B.; Lu, Z. H.

    2011-10-31

    The energy-level alignment at metal/organic interfaces has traditionally been studied using ultraviolet photoelectron spectroscopy (UPS) in ultra-high vacuum (UHV). However, since most devices are fabricated in high vacuum (HV), these studies do not accurately reflect the interfaces in real devices. We demonstrate, using UPS measurements of samples prepared in HV and UHV and current-voltage measurements of devices prepared in HV, that the small amounts of residual gases that are adsorbed on the surface of clean Cu, Ag, and Au (i.e., the noble metals) in HV can significantly alter the energy-level alignment at metal/organic interfaces.

  9. The solubility of the noble gases He, Ne, Ar, Kr, and Xe in water up to the critical point

    USGS Publications Warehouse

    Potter, R.W.; Clynne, M.A.

    1978-01-01

    The solubility of the noble gases Ar, He, Ne, Kr, and Xe in pure water was measured from 298 to 561??K. These data in turn were extrapolated to the critical point of water, thus providing a complete set of Henry's law constants from 274 to 647??K when combined with the existing literature data. Equations describing the behavior of the Henry's law constants over this temperature range are also given. The data do not confirm extrapolations of empirical correlations based on low-temperature solubility data. ?? 1978 Plenum Publishing Corporation.

  10. A comprehensive study of noble gases and nitrogen in "Hypatia", a diamond-rich pebble from SW Egypt

    NASA Astrophysics Data System (ADS)

    Avice, Guillaume; Meier, Matthias M. M.; Marty, Bernard; Wieler, Rainer; Kramers, Jan D.; Langenhorst, Falko; Cartigny, Pierre; Maden, Colin; Zimmermann, Laurent; Andreoli, Marco A. G.

    2015-12-01

    This is a follow-up study of a work by Kramers et al. (2013) on a very unusual diamond-rich rock fragment found in the area of south west Egypt in the south-western side of the Libyan Desert Glass strewn field. This pebble, called Hypatia, is composed of almost pure carbon. Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD) results reveal that Hypatia is mainly made of defect-rich diamond containing lonsdaleite and multiple deformation bands. These characteristics are compatible with an impact origin on Earth and/or in space. We also analyzed concentrations and isotopic compositions of all five noble gases and nitrogen in several ∼mg sized Hypatia samples. These data confirm the conclusion by Kramers et al. (2013) that Hypatia is extra-terrestrial. The sample is relatively rich in trapped noble gases with an isotopic composition being close to the Q component found in many types of meteorites. 40Ar/36Ar ratios in individual steps are as low as 0.4 ± 0.3. Cosmic-ray produced ;cosmogenic; 21Ne is present in concentrations corresponding to a nominal cosmic-ray exposure (CRE) age of roughly 0.1 Myr if produced in a typical meter-sized meteoroid. Such an atypically low nominal CRE age suggests high shielding in a considerably larger body. In addition to the Xe-Q composition, an excess of radiogenic 129Xe (from the decay of short-lived radioactive 129I) is observed (129Xe /132Xe = 1.18 + / - 0.03). Two isotopically distinct N components are present, an isotopically heavy component (δ15N ∼ + 20 ‰) released at low temperatures and a major isotopically light component (δ15N ∼ - 110 ‰) at higher temperatures. This disequilibrium in N suggests that the diamonds in Hypatia were formed in space rather than upon impact on Earth (δN15atm = 0 ‰). All our data are broadly consistent with concentrations and isotopic compositions of noble gases in at least three different types of carbon-rich meteoritic materials: carbon-rich veins in ureilites

  11. Theoretical calculation of transport properties of the noble gases He and Ne and their binary mixtures at low density

    SciTech Connect

    Li Xiufeng; Li Xi

    1996-08-01

    Using the Tang-Toennies potential model and a set of expressions given by J. Kestin et al., we calculate the transport properties of the two noble gases He and Ne and of their binary mixtures, based upon the calculation of the interaction potential. Our calculated results for the transport properties are restricted to low densities but cover the full temperature interval extending from 50 K to the onset of ionization; the mole fraction of the binary mixtures is x{sub 1}:x{sub 2} = 0.25:0.75. Our results are comparable to the best theoretical results given by J. Kestin et al.

  12. Multidiffusion mechanisms for noble gases (He, Ne, Ar) in silicate glasses and melts in the transition temperature domain: Implications for glass polymerization

    NASA Astrophysics Data System (ADS)

    Amalberti, Julien; Burnard, Pete; Laporte, Didier; Tissandier, Laurent; Neuville, Daniel R.

    2016-01-01

    Noble gases are ideal probes to study the structure of silicate glasses and melts as the modifications of the silicate network induced by the incorporation of noble gases are negligible. In addition, there are systematic variations in noble gas atomic radii and several noble gas isotopes with which the influence of the network itself on diffusion may be investigated. Noble gases are therefore ideally suited to constrain the time scales of magma degassing and cooling. In order to document noble gas diffusion behavior in silicate glass, we measured the diffusivities of three noble gases (4He, 20Ne and 40Ar) and the isotopic diffusivities of two Ar isotopes (36Ar and 40Ar) in two synthetic basaltic glasses (G1 and G2; 20Ne and 36Ar were only measured in sample G1). These new diffusion results are used to re-interpret time scales of the acquisition of fractionated atmospheric noble gas signatures in pumices. The noble gas bearing glasses were synthesized by exposing the liquids to high noble gas partial pressures at high temperature and pressure (1750-1770 K and 1.2 GPa) in a piston-cylinder apparatus. Diffusivities were measured by step heating the glasses between 423 and 1198 K and measuring the fraction of gas released at each temperature step by noble gas mass spectrometry. In addition we measured the viscosity of G1 between 996 and 1072 K in order to determine the precise glass transition temperature and to estimate network relaxation time scales. The results indicate that, to a first order, that the smaller the size of the diffusing atom, the greater its diffusivity at a given temperature: D(He) > D(Ne) > D(Ar) at constant T. Significantly, the diffusivities of the noble gases in the glasses investigated do not display simple Arrhenian behavior: there are well-defined departures from Arrhenian behavior which occur at lower temperatures for He than for Ne or Ar. We propose that the non-Arrhenian behavior of noble gases can be explained by structural modifications

  13. Composition of solar wind noble gases released by surface oxidation of a metal separate from the Weston meteorite

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Pepin, R. O.

    1991-01-01

    The paper reports on a set of experiments intended to test the feasibility of determining elemental and isotopic ratios of the noble gases and nitrogen in the solar wind in metal separates from gas-rich ordinary chondrites. Helium, neon, and argon show clear evidence of a solar wind signature, while no solar component could be identified for xenon and nitrogen. Helium, neon, and argon elemental isotopic ratios appear to depend on depth within the metal grains. The ratios derived indicate that the Weston meteorite did not acquire its solar wind gases from a recent exposure to solar wind, but more probably at a time in the past similar to or even earlier than the exposure time of Apollo 17 breccias. The Ar-36/Ar-38 ratio, in tandem with other recent determinations of this value, indicates that the solar and terrestrial values can no longer be assumed to be equivalent.

  14. Noble Gases in Recently Found Hot and Cold Desert Lunar Meteorites

    NASA Astrophysics Data System (ADS)

    Will, P.; Maden, C.; Busemann, H.

    2016-08-01

    We report He-Xe noble gas data for 7 lunar meteorites. Of 4 paired and unbrecciated mare basalts 2 surprisingly contain abundant solar wind - so far unknown for mare basalts. Potential implications for our understanding of the Moon will be discussed.

  15. Noble Gases in Giant Cluster IDP U2-20GCA

    NASA Astrophysics Data System (ADS)

    Pepin, R. O.; Palma, R. L.; Schlutter, D. J.; Brownlee, D. E.; Joswiak, D.

    2015-07-01

    Noble gas analyses of 15 particles from U2-20GCA reveal a suite of trapped 20Ne/22Ne ratios similar to HL-Ne, Q-Ne and SW-Ne. Highly spallogenic 21Ne/22Ne points to past residence in an environment of intense energetic proton radiation.

  16. Noble gases in submarine pillow basalt glasses from Loihi and Kilauea, Hawaii: A solar component in the Earth

    SciTech Connect

    Honda, M.; McDougall, I.; Patterson, D.B.; Doulgeris, A. ); Clague, D.A. )

    1993-02-01

    Noble gas elemental and isotopic abundances have been analysed in twenty-two samples of basaltic glass dredged from the submarine flanks of two currently active Hawaiian volcanoes, Loihi Seamount and Kilauea. Neon isotopic ratios are enriched in [sup 20]Ne and [sup 21]Ne by as much as 16% with respect to atmospheric ratios. All the Hawaiian basalt glass samples show relatively high [sup 3]He/[sup 4]He ratios. The high [sup 20]Ne/[sup 22]Ne values in some of the Hawaiian samples, together with correlations between neon and helium systematics, suggest the presence of a solar component in the source regions of the Hawaiian mantle plume. The solar hypothesis for the Earth's primordial noble gas composition can account for helium and neon isotopic ratios observed in basaltic glasses from both plume and spreading systems, in fluids in continental hydrothermal systems, in CO[sub 2] well gases, and in ancient diamonds. These results provide new insights into the origin and evolution of the Earth's atmosphere.

  17. Measuring the spin polarization of alkali-metal atoms using nuclear magnetic resonance frequency shifts of noble gases

    SciTech Connect

    Liu, X. H.; Luo, H.; Qu, T. L. Yang, K. Y.; Ding, Z. C.

    2015-10-15

    We report a novel method of measuring the spin polarization of alkali-metal atoms by detecting the NMR frequency shifts of noble gases. We calculated the profile of {sup 87}Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the {sup 87}Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the {sup 87}Rb atoms and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system.

  18. GAS-PHASE SEQUESTRATION OF NOBLE GASES IN THE PROTOSOLAR NEBULA: POSSIBLE CONSEQUENCES ON THE OUTER SOLAR SYSTEM COMPOSITION

    SciTech Connect

    Pauzat, F.; Ellinger, Y.; Ozgurel, O.; Mousis, O.; Ali Dib, M. E-mail: ellinger@lct.jussieu.fr E-mail: olivier.mousis@obs-besancon.fr

    2013-11-01

    We address the problem of the sequestration of Ar, Kr, and Xe by H{sub 3}{sup +} in the gas-phase conditions encountered during the cooling of protoplanetary disks when H{sub 3}{sup +} is competing with other species present in the same environment. Using high-level ab initio simulations, we try to quantify other sequestration possibilities involving He, H{sub 5}{sup +}, H{sub 2}O, and H{sub 3}O{sup +} present in the protosolar nebula. Apart from the fact that H{sub 3}{sup +} complexes formed with heavy noble gases are found to be by far much more stable than those formed with He or H{sub 2}O, we show that H{sub 2}D{sup +} and H{sub 3}O{sup +}, both products of the reactions of H{sub 3}{sup +} with HD and H{sub 2}O, can also be efficient trapping agents for Ar, Kr, and Xe. Meanwhile, the abundance profile of H{sub 3}{sup +} in the outer part of the nebula is revisited with the use of an evolutionary accretion disk model that allows us to investigate the possibility that heavy noble gases can be sequestered by H{sub 3}{sup +} at earlier epochs than those corresponding to their trapping in planetesimals. We find that H{sub 3}{sup +} might be abundant enough in the outer protosolar nebula to trap Xe and Kr prior their condensation epochs, implying that their abundances should be solar in Saturn's current atmosphere and below the observational limit in Titan. The same scenario predicts that comets formed at high heliocentric distances should also be depleted in Kr and Xe. In situ measurements, such as those planed with the Rosetta mission on 67P/Churyumov-Gerasimenko, will be critical to check the validity of our hypotheses.

  19. Shock-implanted noble gases - An experimental study with implications for the origin of Martian gases in shergottite meteorites

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Horz, Friedrich; Johnson, Pratt H.

    1986-01-01

    The shock-implantation of gases is studied by artificially shocking whole rock and power samples of terrestrial basalt to pressures of 2-40 GPa. Ar, Kr, Xe, and Ne were implanted into the silicate. It is observed that the amount of implanted gas is linearly proportional to its partial pressure over a pressure range of 0.0001 to 0.1 atmosphere. The fractionation effect in the implanted gas and the gas diffusion properties are examined. The amounts of gas that would have been implanted with 100 percent efficiency are calculated from the measured porosities of the power samples and are compared to observed abundances. It is determined that the implantation efficiencies are approximately 0.5 percent at 2 GPa, 7 percent at 5 GPa, and greater than 50 percent at both 20 and 35 GPa. The experimental data correlate with the shock implantation of Martian gases without mass fractionation into the shock-melted phase of meteorite EETA 79001.

  20. Intensive sampling of noble gases in fluids at Yellowstone: I. Early overview of the data; regional patterns

    NASA Astrophysics Data System (ADS)

    Kennedy, B. M.; Lynch, M. A.; Reynolds, J. H.; Smith, S. P.

    1985-05-01

    The Roving Automated Rare Gas Analysis (RARGA) lab of Berkeley's Physics Department was deployed in Yellowstone National Park for a 19 week period commencing in June, 1983. During this time 66 gas and water samples representing 19 different regions of hydrothermal activity within and around the Yellowstone caldera were analyzed on site. Routinely, the abundances of five stable noble gases and the isotopic compositions of He, Ne, and Ar were determined for each sample. In a few cases the isotopes of Kr and Xe were also determined and found to be of normal atmospheric constitution. Correlated variations in the isotopic compositions of He and Ar can be explained within the precision of the measurements by mixing of only three distinct components. The first component is of magmatic origin and is enriched in the primordial isotope 3He with 3He /4He ≥ 16 times the air value. This component also contains radiogenic 40Ar and possible 36Ar with 40Ar /36Ar ≥ 500 , resulting in a 3He /36Ar ratio ≥ 41,000 times the air value. The second component is assumed to be purely radiogenic 4He and 40Ar ( 4∗He /40∗Ar = 4.08 ± .33 ). This component is the probable carrier of observed excesses of 21∗Ne, attributed to the α,n reaction on 18O. Its radiogenic character implies a crustal origin in U. Th, and Krich aquifer rocks. The third component, except for possible mass fractionation, is isotopically indistinguishable from the noble gases in the atmosphere. This component originates largely from infiltrating run-off water saturated with atmospheric gases. In addition to exhibiting nucleogenic 21∗Ne, Ne data show anomalies in the ratio 20Ne /20Ne , which correlate roughly with the 21Ne /22Ne anomalies for the most part, but not as would occur from simple mass fractionation. Some exaggerated instances of the 20Ne /22Ne anomaly occur which could be explained by combined mass fractionation of Ne and Ar isotopes to a severe degree coupled with remixing with normally isotopic

  1. Diverging effects of isotopic fractionation upon molecular diffusion of noble gases in water: mechanistic insights through ab initio molecular dynamics simulations.

    PubMed

    Pinto de Magalhães, Halua; Brennwald, Matthias S; Kipfer, Rolf

    2017-02-10

    Atmospheric noble gases are routinely used as natural tracers to analyze gas transfer processes in aquatic systems. Their isotopic ratios can be employed to discriminate between different physical transport mechanisms by comparison to the unfractionated atmospheric isotope composition. In many applications of aquatic systems molecular diffusion was thought to cause a mass dependent fractionation of noble gases and their isotopes according to the square root ratio of their masses. However, recent experiments focusing on isotopic fractionation within a single element challenged this broadly accepted assumption. The determined fractionation factors of Ne, Ar, Kr and Xe isotopes revealed that only Ar follows the prediction of the so-called square root relation, whereas within the Ne, Kr and Xe elements no mass-dependence was found. The reason for this unexpected divergence of Ar is not yet understood. The aim of our computational exercise is to establish the molecular-resolved mechanisms behind molecular diffusion of noble gases in water. We make the hypothesis that weak intermolecular interactions are relevant for the dynamical properties of noble gases dissolved in water. Therefore, we used ab initio molecular dynamics to explicitly account for the electronic degrees of freedom. Depending on the size and polarizability of the hydrophobic particles such as noble gases, their motion in dense and polar liquids like water is subject to different diffusive regimes: the inter-cavity hopping mechanism of small particles (He, Ne) breaks down if a critical particle size achieved. For the case of large particles (Kr, Xe), the motion through the water solvent is governed by mass-independent viscous friction leading to hydrodynamical diffusion. Finally, Ar falls in between the two diffusive regimes, where particle dispersion is propagated at the molecular collision time scale of the surrounding water molecules.

  2. High resolution diode laser spectroscopy of H2O spectra broadened by nitrogen and noble gases

    NASA Astrophysics Data System (ADS)

    Kapitanov, Venedikt A.; Osipov, Konstantin Yu.; Protasevich, Alexander E.; Ponurovskiy, Yakov Ya.

    2014-11-01

    The absorption spectra of pure H2O with mixtures of broadening gases N2, Ar, Xe, He, Ar and air have been measured in 1.39 mμ spectral region by high resolution spectrometer based on diode laser (DFB NEL, Japan). For the processing of pure water spectra and it's mixtures with a different broadening gases in a wide pressure range we used a multispectrum fitting procedure developed at IAO. The program is based on a relatively simple Rautian-Sobel'man line profile and linear pressure dependence of the line profile parameters. H2O measured spectra bulk processing results in the retrieving of such line parameters: zero-pressure line center positions, intensities, self-broadening and self-shift coefficients of pure water, broadening and shift coefficients for other gases which are describes the experiment with the minimum residuals in a wide pressure range.

  3. Irradiation History of Itokawa Regolith Material Deduced from Noble Gases in the Hayabusa Samples

    NASA Astrophysics Data System (ADS)

    Nagao, Keisuke; Okazaki, Ryuji; Nakamura, Tomoki; Miura, Yayoi N.; Osawa, Takahito; Bajo, Ken-ichi; Matsuda, Shintaro; Ebihara, Mitsuru; Ireland, Trevor R.; Kitajima, Fumio; Naraoka, Hiroshi; Noguchi, Takaaki; Tsuchiyama, Akira; Yurimoto, Hisayoshi; Zolensky, Michael E.; Uesugi, Masayuki; Shirai, Kei; Abe, Masanao; Yada, Toru; Ishibashi, Yukihiro; Fujimura, Akio; Mukai, Toshifumi; Ueno, Munetaka; Okada, Tatsuaki; Yoshikawa, Makoto; Kawaguchi, Junichiro

    2011-08-01

    Noble gas isotopes were measured in three rocky grains from asteroid Itokawa to elucidate a history of irradiation from cosmic rays and solar wind on its surface. Large amounts of solar helium (He), neon (Ne), and argon (Ar) trapped in various depths in the grains were observed, which can be explained by multiple implantations of solar wind particles into the grains, combined with preferential He loss caused by frictional wear of space-weathered rims on the grains. Short residence time of less than 8 million years was implied for the grains by an estimate on cosmic-ray-produced 21Ne. Our results suggest that Itokawa is continuously losing its surface materials into space at a rate of tens of centimeters per million years. The lifetime of Itokawa should be much shorter than the age of our solar system.

  4. MRI of the lung gas-space at very low-field using hyperpolarized noble gases

    NASA Technical Reports Server (NTRS)

    Venkatesh, Arvind K.; Zhang, Adelaide X.; Mansour, Joey; Kubatina, Lyubov; Oh, Chang Hyun; Blasche, Gregory; Selim Unlu, M.; Balamore, Dilip; Jolesz, Ferenc A.; Goldberg, Bennett B.; Albert, Mitchell S.

    2003-01-01

    In hyperpolarized (HP) noble-gas magnetic resonance imaging, large nuclear spin polarizations, about 100,000 times that ordinarily obtainable at thermal equilibrium, are created in 3He and 129Xe. The enhanced signal that results can be employed in high-resolution MRI studies of void spaces such as in the lungs. In HP gas MRI the signal-to-noise ratio (SNR) depends only weakly on the static magnetic field (B(0)), making very low-field (VLF) MRI possible; indeed, it is possible to contemplate portable MRI using light-weight solenoids or permanent magnets. This article reports the first in vivo VLF MR images of the lungs in humans and in rats, obtained at a field of only 15 millitesla (150 Gauss).

  5. Resonance Ionization of Heavy Noble Gases: The Potential of KR and Xe Measurements from Single Pre-Solar Grains

    NASA Astrophysics Data System (ADS)

    Thonnard, N.

    1995-09-01

    Since the first reliable indication of the existence of non-terrestrial composition of Xe isotopes in meteorites by Reynolds [1,2], anomalies have been found in the isotopic composition of many elements in meteorites, implying a plurality of nucleosynthetic processes, and indicating that the initial conditions leading to the formation of the solar system were quite diverse [3]. Noble gases provide a unique window into the composition of the progenitor material to the solar system [4]. Stellar evolution may contribute by the s-process, r-process, p-process, etc., each with its own isotopic distribution. Kr and Xe are especially useful as the large number of isotopes (7 in the 78Kr to 86Kr range, and 9 in the 124Xe to 136Xe range) provide many clues to help unravel the multiple sources to the measured abundances. Although Xe has been measured and analyzed considerably more frequently than Kr in meteorite studies, this has only partially been due to the wealth of information derivable from Xe studies, but also, due to experimental difficulties encountered in Kr measurements. Early in the development of stellar nucleosynthesis, 86Kr was proposed as a chronometer of the s-process [5], but until recently has provided unreliable results [6]. Other interesting properties derivable from Kr isotope measurements include 78Kr as an indication of spallation history, 80Kr as a stellar thermometer, and 81Kr and 83Kr to determine cosmic ray exposure ages. Studies of highly refractory microscopic grains (diamond, graphite and SiC) separated from the much more abundant carbonaceous matrix in primitive meteorites have shown a remarkable isotopic composition diversity in a small fraction of single grains from the same meteorite, implying multiple stellar sources [4]. Ion microprobe measurements have been possible of the major constituents of single interstellar grains [7,8] and of He and Ne using a state-of-the-art static noble gas mass spectrometer [9-11]. But, a recent attempt to

  6. Noble gases in anhydrous mantle xenoliths from Tasmania in comparison with other localities from eastern Australia: Implications for the tectonic evolution

    NASA Astrophysics Data System (ADS)

    Czuppon, György; Matsumoto, Takuya; Matsuda, Jun-ichi; Everard, John; Sutherland, Lin

    2010-11-01

    Ultramafic xenoliths from Tasmanian basalts were analysed for elemental and isotopic compositions of noble gases, for greater understanding of the evolution of the underlying subcontinental lithosphere. The noble gas isotopic compositions indicate contributions of radiogenic and MORB-like components to the xenoliths. The MORB-like component is characterized by 3He/ 4He ratios between 7 and 9 Ra while the radiogenic component shows lower 3He/ 4He ratios than those in MORB (8.75 ± 2.14 Ra, Graham, 2002). The identified radiogenic component in xenoliths from Tasmania may stem from subduction events, during which the mantle wedge and subcontinental lithospheric mantle were metasomatised by U- and Th-rich fluids. As subduction processes have played important role in the evolution of Eastern Australia during the Paleozoic, the radiogenic component is probably associated with this event. Incorporation of MORB-like noble gases in the subcontinental lithospheric mantle beneath Tasmania is likely related to extensional rifting and associated opening of the Tasman Sea in the Late Mesozoic and Cenozoic. The identified noble gas components of the xenoliths are consistent with the geochemical character of the host basalt based on the radiogenic isotope and trace element systematics. This agreement and the petrographic observations (e.g. fluid inclusion trails connected with the reaction rim of the minerals close to the host basalt, spongy texture) indicate that fluids (noble gases, CO 2) most likely propagated from the host basalts to the xenoliths forming fluid inclusions. The observed noble gas isotopic heterogeneity in mantle-derived xenoliths from Tasmanian to North Queensland reflects isotopic heterogeneity at regional scale in the subcontinental lithospheric mantle beneath eastern Australia.

  7. Analysis of groundwater dynamics in the complex aquifer system of Kazan Trona, Turkey, using environmental tracers and noble gases

    NASA Astrophysics Data System (ADS)

    Arslan, Sebnem; Yazicigil, Hasan; Stute, Martin; Schlosser, Peter; Smethie, William M.

    2015-02-01

    The Eocene deposits of Kazan Basin in Turkey contain a rare trona mineral which is planned to be extracted by solution mining. The complex flow dynamics and mixing mechanisms as noted from previous hydraulic and hydrochemical data need to be augmented with environmental tracer and noble gas data to develop a conceptual model of the system for the assessment of the impacts of the mining and to develop sustainable groundwater management policies throughout the area. The tracers used include the stable isotopes of water (δ2H, δ18O), δ13C and 14C of dissolved inorganic carbon (DIC), tritium (3H), the chlorofluorocarbons CFC-11 and CFC-12, and the noble gases He and Ne. The system studied consists of three aquifers: shallow, middle, and deep. CFC data indicate modern recharge in the shallow system. The estimates of ages through 14C dating for the deeper aquifer system are up to 34,000 years. Helium concentrations cover a wide range of values from 5 × 10-8 to 1.5 × 10-5 cm3 STP/g. 3He/4He ratios vary from 0.09RA to 1.29RA (where RA is the atmospheric 3He/4He ratio of 1.384 × 10-6), the highest found in water from the shallow aquifer. Mantle-derived 3He is present in some of the samples indicating upward groundwater movement, possibly along a NE-SW-striking fault-like feature in the basin.

  8. Relationships between Noble Gases and Indicators of Geochemical Enrichment in Carbonatite Metasomatized Xenoliths from Samoa

    NASA Astrophysics Data System (ADS)

    Kukolich, S.; Jackson, M. G.; Kurz, M. D.

    2012-12-01

    Rejuvenated lavas from oceanic hotspots can host peridotite mantle xenoliths that provide windows into the composition and history of the upper mantle. Peridotite xenoliths hosted in Samoan rejuvenated lavas from the Island of Savaiíi exhibit evidence for variable enrichment by carbonatitic melts. Some xenoliths are trace element depleted, while others host incompatible element budgets on par with enriched alkali basalts (Hauri and Hart, 1994). The most incompatible element enriched xenoliths have 87Sr/86Sr ratios (up to 0.7128) that are the highest observed in the oceanic mantle. Poreda and Farley (1992) examined the noble gas isotopic compositions of a different suite of xenoliths from the same locality. They identified a narrow range of 3He/4He ratios (8.6 to 12.04 Ra), while the neon isotopic compositions spanned an enormous range, from the Loihi-Kileaua line (unradiogenic) to the MORB line. The xenoliths with the highest 3He/4He have neon isotopes that are most unradiogenic, while samples with lower 3He/4He have MORB-like neon isotopic compositions. It is not known which xenoliths in this suite have experienced carbonatite metasomatism, as lithophile element concentrations were not reported by Poreda and Farley (1992), and the noble gas signature associated with carbonatite metasomatism beneath Samoa is unknown. We report new helium measurements on olivine and orthopyroxene separates from 14 Savaii peridotite xenoliths that were previously characterized by Hauri and Hart (1994) and Hauri et al (1993). All samples are extremely fresh. Their 3He/4He ratios span 11.6 to 12.41 Ra, at the high end of the range reported by Poreda and Farley (1992). We also report whole-rock trace element abundances on these xenoliths (trace elements on individual clinopyroxenes from each sample were reported by Hauri and Hart and Hauri et al (1993)). The xenoliths that exhibit trace element evidence for enrichment from carbonatite fluids (low Nb/U, and high La/Nd and Nb/Ta) have

  9. Microstructures, mineral chemistry, noble gases and nitrogen in the recent fall, Bhuka iron (IAB) meteorite

    NASA Astrophysics Data System (ADS)

    Murty, S. V. S.; Ranjith, P. M.; Ray, Dwijesh; Ghosh, S.; Chattopadhyay, Basab; Shrivastava, K. L.

    2016-10-01

    We report some chemical, petrological and isotopic studies of the Bhuka iron meteorite that fell in Rajasthan, India in 2005. Numerous silicate and graphite inclusions are visible on the surface of the hand specimen. In the polished and etched surface studied, irregular patches of graphite are found as the most dominant inclusion and commonly associated with pure corundum (95 wt% Al2O3), spinel, feldspar and Si-rich phases. Apart from typical lamellar intergrowth with kamacite (i.e. the Widmänstatten pattern), taenites are also commonly found to occur as a rim of the graphite inclusions. P-rich (up to 10 wt%) taenites are also found locally within the recrystallised kamacite matrix. Based on mineralogy, texture and bulk composition, Bhuka resembles the low-Ni IAB subgroup (ungrouped). Noble gas isotope studies suggest He, Ne and Ar are mostly of cosmogenic origin, while Kr and Xe are a mixture of cosmogenic, radiogenic and trapped components. A pre-atmospheric radius of 10±1 cm and a cosmic ray exposure age of 346±52 Ma are derived based on depth dependant (3He/4He)c and 38Arc respectively, as per the production systematics of cosmogenic noble gas isotopes (Ammon et al., 2009). Cosmogenic 83Kr and 126Xe yield production rates of 12 and 0.335 (in 10-15ccSTP/g Ma) for 83Kr and 126Xe respectively. Presence of trapped Kr and Xe, with (84Kr/132Xe)t=2 and radiogenic 129Xe=120×10-12 ccSTP/g are due to presence of graphite/silicate inclusions in the analysed sample. Over ~150% excess 131Xec than expected from spallation suggests contribution from (n,ɤ) reactions from Ba from inclusions and suggests irradiation of pre-atmospheric object in a larger body, indicative of complex irradiation. Trapped N of 24 ppm, with δ15N=-10.7±0.8‰ observed in Bhuka, is heavier than the range observed hither to in IAB irons.

  10. Sedimentary halogens and noble gases within Western Antarctic xenoliths: Implications of extensive volatile recycling to the sub continental lithospheric mantle

    NASA Astrophysics Data System (ADS)

    Broadley, Michael W.; Ballentine, Chris J.; Chavrit, Déborah; Dallai, Luigi; Burgess, Ray

    2016-03-01

    Recycling of marine volatiles back into the mantle at subduction zones has a profound, yet poorly constrained impact on the geochemical evolution of the Earth's mantle. Here we present a combined noble gas and halogen study on mantle xenoliths from the Western Antarctic Rift System (WARS) to better understand the flux of subducted volatiles to the sub continental lithospheric mantle (SCLM) and assess the impact this has on mantle chemistry. The xenoliths are extremely enriched in the heavy halogens (Br and I), with I concentrations up to 1 ppm and maximum measured I/Cl ratios (85.2 × 10-3) being ∼2000 times greater than mid ocean ridge basalts (MORB). The Br/Cl and I/Cl ratios of the xenoliths span a range from MORB-like ratios to values similar to marine pore fluids and serpentinites, whilst the 84Kr/36Ar and 130Xe/36Ar ratios range from modern atmosphere to oceanic sediments. This indicates that marine derived volatiles have been incorporated into the SCLM during an episode of subduction related metasomatism. Helium isotopic analysis of the xenoliths show average 3He/4He ratios of 7.5 ± 0.5 RA (where RA is the 3He/4He ratio of air = 1.39 × 10-6), similar to that of MORB. The 3He/4He ratios within the xenoliths are higher than expected for the xenoliths originating from the SCLM which has been extensively modified by the addition of subducted volatiles, indicating that the SCLM beneath the WARS must have seen a secondary alteration from the infiltration and rise of asthenospheric fluids/melts as a consequence of rifting and lithospheric thinning. Noble gases and halogens within these xenoliths have recorded past episodes of volatile interaction within the SCLM and can be used to reconstruct a tectonic history of the WARS. Marine halogen and noble gas signatures within the SCLM xenoliths provide evidence for the introduction and retention of recycled volatiles within the SCLM by subduction related metasomatism, signifying that not all volatiles that survive

  11. The Role of Noble Gases in Defining the Mean Residence Times of Fluids within Precambrian Crustal Systems

    NASA Astrophysics Data System (ADS)

    Warr, O.; Sherwood Lollar, B.; Fellowes, J.; Sutcliffe, C. N.; McDermott, J. M.; Holland, G.; Mabry, J.; Ballentine, C. J.

    2015-12-01

    Brines rich in N2, H2, CH4 and He hosted within Precambrian crustal rocks are known to sustain microbial life [1]. The geological systems containing these brines have the potential to isolate organisms over planetary timescales and so can provide unique insight into the diversity and evolution of terrestrial life [1-3]. Long considered geological outliers, the prevalence of systems containing these ancient, deep fracture waters is only now being revealed. Recent studies demonstrate the Precambrian crust which accounts for ~70% of total crustal surface area has a global hydrogen production comparable to marine systems [2]. In addition to H2-producing reactions (e.g. radiolysis and serpentinization), a diversity of CH4-producing reactions also occur in these systems through both microbial and water-rock interactions [1, 2]. However, the role these Precambrian systems have in global hydrogen and carbon cycles is poorly understood. For this we need good constraints on the origins, residence times and degree of microbial activity of the fluids within these systems as well as the degree of interaction with external systems. Fortunately, noble gases are ideal for this role [1,3]. Previous noble gas analysis of N2, H2, CH4 and He-rich fluid samples collected at 2.4 km depth from a Cu-Zn mine in Timmins, Ontario, identified isolated fracture fluids with the oldest residence times ever observed (>1.1 Ga) [3]. This study has been significantly expanded now to fluids from an even greater depth (3 km) at Timmins, and from two new mines in the Sudbury Basin. Preliminary data from the deeper Timmins level indicate a new closed system with 136Xe/130Xe ratios 93% above modern air values (20% at 2.4 km) and an early atmosphere 124Xe/130Xe signal approaching the age of the host rock (~2.7 Ga) [4]. In comparison, the Sudbury system indicates exchange with an external source, being highly enriched in helium (30% gas volume) but with a low fissiogenic 136Xe/130Xe excess (10-38% above

  12. Relativistic contributions to single and double core electron ionization energies of noble gases.

    PubMed

    Niskanen, J; Norman, P; Aksela, H; Agren, H

    2011-08-07

    We have performed relativistic calculations of single and double core 1s hole states of the noble gas atoms in order to explore the relativistic corrections and their additivity to the ionization potentials. Our study unravels the interplay of progression of relaxation, dominating in the single and double ionization potentials of the light elements, versus relativistic one-electron effects and quantum electrodynamic effects, which dominate toward the heavy end. The degree of direct relative additivity of the relativistic corrections for the single electron ionization potentials to the double electron ionization potentials is found to gradually improve toward the heavy elements. The Dirac-Coulomb Hamiltonian is found to predict a scaling ratio of ∼4 for the relaxation induced relativistic energies between double and single ionization. Z-scaling of the computed quantities were obtained by fitting to power law. The effects of nuclear size and form were also investigated and found to be small. The results indicate that accurate predictions of double core hole ionization potentials can now be made for elements across the full periodic table.

  13. Numerical study of light-induced drift of Na in noble gases

    NASA Astrophysics Data System (ADS)

    Haverkort, J. E. M.; Werij, H. G. C.; Woerdman, J. P.

    1988-10-01

    We present a model for light-induced drift (LID) in the Na-noble-gas system which should enable direct comparison with experiment. In contrast to previous theories of LID based on a two-level description of the optical absorbers and on a simplified collision treatment, the present model is based on a realistic description of laser-driven Na atoms immersed in a buffer gas. Starting from the generalized Bloch equations, we introduce a rate-equation model for the velocity distributions in the four important Na levels. The velocity-changing and fine-structure-changing collisions are described using composite Keilson-Storer collision kernels in which all adjustable parameters have been eliminated by using available literature data. We apply the model in numerical calculations of LID as a function of all experimentally accessible parameters. It is found that the ground-state hyperfine splitting can have large effects on LID, whereas the excited-state fine-structure splitting has not. The paper establishes criteria for optimum LID effects; when using a single-frequency laser the maximum attainable drift velocity is predicted to be 13.8 m/s. Using a proper set of boundary conditions, we find a pressure dependence of LID qualitatively different from the predictions based on previous work. Finally, the influence of the collision model is investigated. We find that LID is independent of the shape of the collision kernel, indicating that a strong-collision model is always valid.

  14. Stratification of discharge in noble gases from the viewpoint of the discrete dynamics

    SciTech Connect

    Golubovskii, Yu. Pelyukhova, E.; Sigeneger, F.; Nekuchaev, V.

    2015-03-15

    Based on the analysis of electron phase trajectories in sinusoidal electric fields, a new point of view on discharge stratification is proposed. It is shown that the positive column can be considered as a spatial resonator in which electric fields with a fundamental period length L{sub S} or higher mode length q/p L{sub S} establish, where p and q are integers and p > q. The fundamental mode length L{sub S} is equivalent to the distance on which electrons gain energy equal to the lowest excitation threshold. This distance determines a length of the S-striation. Unlike kinetic theory, in the presented model resonance properties of the discharge column are not connected with elastic collision energy losses. A point map is used to obtain the resonance trajectories of electrons in the phase plane. Stable points for the positions of inelastic collisions in the resonance trajectories have been found at the positions of field maxima in the case of integer ratios p/q . For non-integer ratios p/q , multiple resonance trajectories arise according to a more complex stability criterion. From this point of view, S-, P-, and R-striations in noble gas discharges can be explained. Due to energy losses in elastic collisions, initial electron energy distribution functions converge to the resonance trajectories (the so-called “bunch effect”). The findings of the discrete model agree with results of kinetic theory and experiment. The new approach avoids difficulties of the kinetic theory in the case of exceptionally large relaxation lengths which can even exceed the positive column length.

  15. Noble gases fingerprint a metasedimentary fluid source in the Macraes orogenic gold deposit, New Zealand

    NASA Astrophysics Data System (ADS)

    Goodwin, Nicholas R. J.; Burgess, Ray; Craw, Dave; Teagle, Damon A. H.; Ballentine, Chris J.

    2017-02-01

    The world-class Macraes orogenic gold deposit (˜10 Moz resource) formed during the late metamorphic uplift of a metasedimentary schist belt in southern New Zealand. Mineralising fluids, metals and metalloids were derived from within the metasedimentary host. Helium and argon extracted from fluid inclusions in sulphide mineral grains (three crush extractions from one sample) have crustal signatures, with no evidence for mantle input (R/Ra = 0.03). Xenon extracted from mineralised quartz samples provides evidence for extensive interaction between fluid and maturing organic material within the metasedimentary host rocks, with 132Xe/36Ar ratios up to 200 times greater than air. Similarly, I/Cl ratios for fluids extracted from mineralised quartz are similar to those of brines from marine sediments that have interacted with organic matter and are ten times higher than typical magmatic/mantle fluids. The Macraes mineralising fluids were compositionally variable, reflecting either mixing of two different crustal fluids in the metasedimentary pile or a single fluid type that has had varying degrees of interaction with the host metasediments. Evidence for additional input of meteoric water is equivocal, but minor meteoric incursion cannot be discounted. The Macraes deposit formed in a metasedimentary belt without associated coeval magmatism, and therefore represents a purely crustal metamorphogenic end member in a spectrum of orogenic hydrothermal processes that can include magmatic and/or mantle fluid input elsewhere in the world. There is no evidence for involvement of minor intercalated metabasic rocks in the Macraes mineralising system. Hydrothermal fluids that formed other, smaller, orogenic deposits in the same metamorphic belt have less pronounced noble gas and halogen evidence for crustal fluid-rock interaction than at Macraes, but these deposits also formed from broadly similar metamorphogenic processes.

  16. Composition of solar flare noble gases preserved in meteorite parent body regolith

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; Garrison, D. H.; Bogard, D. D.; Badhwar, G.; Murali, A. V.

    1991-01-01

    Isotopic composition of solar-flare (SF) Ne was determined in acid-etched pyroxene mineral separates from the Kapoeta meteorite, a brecciated meteorite known to contain implanted solar gases. The results yield the SF Ne-20/Ne-22 ratio of 11.6 +/-0.2, confirming previous determinations of this SF ratio in lunar and meteoritic samples. The same SF Ne composition was also obtained by applying an ordinate intercept technique to the same data set. The ordinate intercept technique was then applied to the Ar and He data. The results are SF Ar-36/Ar-38 = 4.9 +/-0.1 and SF He-4/He-3 = 3800 +/-200. These values are significantly different from the solar-wind (SW) Ar and He values. It is estimated that the concentration of the SF component in Kapoeta pyroxenes is about 20 percent that of the SW component, orders of magnitude higher than expected from SW and SF proton flux measurements.

  17. Proton affinities of maingroup-element hydrides and noble gases: trends across the periodic table, structural effects, and DFT validation.

    PubMed

    Swart, Marcel; Rösler, Ernst; Bickelhaupt, F Matthias

    2006-10-01

    We have carried out an extensive exploration of the gas-phase basicity of archetypal neutral bases across the periodic system using the generalized gradient approximation (GGA) of the density functional theory (DFT) at BP86/QZ4P//BP86/TZ2P. First, we validate DFT as a reliable tool for computing proton affinities and related thermochemical quantities: BP86/QZ4P//BP86/TZ2P is shown to yield a mean absolute deviation of 2.0 kcal/mol for the proton affinity at 298 K with respect to experiment, and 1.2 kcal/mol with high-level ab initio benchmark data. The main purpose of this work is to provide the proton affinities (and corresponding entropies) at 298 K of the neutral bases constituted by all maingroup-element hydrides of groups 15-17 and the noble gases, that is, group 18, and periods 1-6. We have also studied the effect of step-wise methylation of the protophilic center of the second- and third-period bases.

  18. Noble gases and halogens in Graves Nunataks 06129: The complex thermal history of a felsic asteroid crust

    NASA Astrophysics Data System (ADS)

    Claydon, Jennifer L.; Crowther, Sarah A.; Fernandes, Vera A.; Gilmour, Jamie D.

    2015-06-01

    The meteorite Graves Nunataks 06128/06129 is a rare example of felsic asteroidal crust. Knowledge of its history can help shed light on the evolution processes of planetesimals. The noble gases can be used to constrain both the chronology of meteorites and the processes that result in movements of volatile elements on asteroidal bodies. We have examined the I-Xe and Ar-Ar systems of the plagioclase-rich achondrite, Graves Nunataks 06129 by high-resolution laser step-heating of irradiated samples. Iodine and 129Xe∗ are both present but are released at different temperatures and do not show a correlation, therefore the I-Xe system in GRA 06129 has no chronological significance. We propose that radiogenic 129Xe∗ was lost from primary phases and parentless 129Xe∗ was later introduced into the rock by interaction with a fluid sourced from a reservoir that evolved with a high I/Xe ratio. This could have been the same halogen-rich fluid that induced the conversion of merrillite and pyroxene into chlorapatite. Inherited 40Ar (i.e. not generated by in situ decay of 40K) is also present in one of three fragments studied here and may have been introduced at the same time as parentless 129Xe∗.

  19. Formation of noble-gas hydrides and decay of solvated protons revisited: diffusion-controlled reactions and hydrogen atom losses in solid noble gases.

    PubMed

    Tanskanen, Hanna; Khriachtchev, Leonid; Lignell, Antti; Räsänen, Markku; Johansson, Susanna; Khyzhniy, Ivan; Savchenko, Elena

    2008-02-07

    UV photolysis and annealing of C2H2/Xe, C2H2/Xe/Kr, and HBr/Xe matrices lead to complicated photochemical processes and reactions. The dominating products in these experiments are noble-gas hydrides with general formula HNgY (Ng = noble-gas atom, Y = electronegative fragment). We concentrate on distinguishing the local and global mobility and losses of H atoms, barriers of the reactions, and the decay of solvated protons. Different deposition temperatures change the amount of lattice imperfections and thus the amount of traps for H atoms. The averaged distance between reacting species influencing the reaction kinetics is controlled by varying the precursor concentration. A number of solid-state processes connected to the formation of noble-gas hydrides and decay of solvated protons are discussed using a simple kinetic model. The most efficient formation of noble-gas hydrides is connected with global (long-range) mobility of H atoms leading to the H + Xe + Y reaction. The highest concentration of noble-gas hydrides was obtained in matrices of highest optical quality, which probably have the lowest concentration of defects and H-atom losses. In matrices with high amount of geometrical imperfections, the product formation is inefficient and dominated by a local (short-range) process. The decay of solvated protons is rather local than a global process, which is different from the formation of noble-gas molecules. However, the present data do not allow distinguishing local proton and electron mobilities. Our previous results indicate that these are electrons which move to positively-charged centers and neutralize them. It is believed that the image obtained here for solid xenon is applicable to solid krypton whereas the case of argon deserves special attention.

  20. Analysis of accommodation coefficients of noble gases on aluminum surface with an experimental/computational method

    NASA Astrophysics Data System (ADS)

    Selden, Nathaniel; Gimelshein, Natalia; Gimelshein, Sergey; Ketsdever, Andrew

    2009-07-01

    A method that connects measurements of radiometric forces on a heated vane in the transitional flow regime with the kinetic modeling of the flow, and derives the accommodation coefficients through the successive analysis of measured and computed results, is proposed. The method utilizes the fact that radiometric forces exerted on heated objects immersed in rarefied gases are governed by the interaction of gas molecules with the surface. Experimental results on radiometric forces on a 0.11 m diameter circular vane are obtained on a nano-Newton thrust stand in a 3 m long vacuum chamber for pressures ranging from approximately 0.01 to 1 Pa. The vane was heated to 419 K on the hot side and 396 K on the cold side. The numerical modeling is conducted using a combined ellipsoidal statistical Bhatnagar-Gross-Krook/direct simulation Monte Carlo approach that allows accurate and time efficient analysis of radiometric forces on a vane in large vacuum chambers filled with rarefied gas. Accommodation coefficients for the Maxwell model are estimated for argon, xenon, and helium on a machined aluminum surface, and found to be 0.81, 0.86, and 0.53, respectively.

  1. Halogens and noble gases in Mathematician Ridge meta-gabbros, NE Pacific: implications for oceanic hydrothermal root zones and global volatile cycles

    NASA Astrophysics Data System (ADS)

    Kendrick, Mark A.; Honda, Masahiko; Vanko, David A.

    2015-12-01

    Six variably amphibolitised meta-gabbros cut by quartz-epidote veins containing high-salinity brine, and vapour fluid inclusions were investigated for halogen (Cl, Br, I) and noble gas (He, Ne, Ar, Kr, Xe) concentrations. The primary aims were to investigate fluid sources and interactions in hydrothermal root zones and determine the concentrations and behaviours of these elements in altered oceanic crust, which is poorly known, but has important implications for global volatile (re)cycling. Amphiboles in each sample have average concentrations of 0.1-0.5 wt% Cl, 0.5-3 ppm Br and 5-68 ppb I. Amphibole has Br/Cl of ~0.0004 that is about ten times lower than coexisting fluid inclusions and seawater, and I/Cl of 2-44 × 10-6 that is 3-5 times lower than coexisting fluid inclusions but higher than seawater. The amphibole and fluid compositions are attributed to mixing halogens introduced by seawater with a large halogen component remobilised from mafic lithologies in the crust and fractionation of halogens between fluids and metamorphic amphibole formed at low water-rock ratios. The metamorphic amphibole and hydrothermal quartz are dominated by seawater-derived atmospheric Ne, Ar, Kr and Xe and mantle-derived He, with 3He/4He of ~9 R/Ra (Ra = atmospheric ratio). The amphibole and quartz preserve high 4He concentrations that are similar to MORB glasses and have noble gas abundance ratios with high 4He/36Ar and 22Ne/36Ar that are greater than seawater and air. These characteristics result from the high solubility of light noble gases in amphibole and suggest that all the noble gases can behave similarly to `excess 40Ar' in metamorphic hydrothermal root zones. All noble gases are therefore trapped in hydrous minerals to some extent and can be inefficiently lost during metamorphism implying that even the lightest noble gases (He and Ne) can potentially be subducted into the Earth's mantle.

  2. Composition of solar flare noble gases preserved in meteorite parent body regolith.

    PubMed

    Rao, M N; Garrison, D H; Bogard, D D; Badhwar, G; Murali, A V

    1991-11-01

    The isotopic composition (long-term average) of solar flare (SF) Ne has been determined by three isotope correlation techniques applied to data measured on chemically etched pyroxene separates prepared from the Kapoeta meteorite, which is known to contain implanted solar gases. The SF 20Ne/22Ne ratio obtained is 11.6 +/- 0.2 and confirms previous determinations of this SF ratio in lunar and meteoritic samples. The same SF Ne composition is also obtained by applying an ordinate intercept technique to the same data set. The ordinate intercept technique was also applied to the Ar and He data, on which the three-isotope correlation technique cannot be applied. The isotopic composition of SF Ar and SF He so obtained are SF 36Ar/38Ar = 4.9 +/- 0.1 and SF 4He/3He = 3800 +/- 200, which are significantly different from the solar wind (SW) Ar and SW He values of approximately 5.35 and approximately 2500, respectively. Correlation between 20Ne/22Ne and 36Ar/38Ar for the same data set also gives a similar SF 36Ar/38Ar ratio of 4.8 +/- 0.2. The determined SF He, Ne and Ar isotopic ratios differ from those in SW by 52%, 17% and 9%, respectively, but the elemental compositions of 4He/36Ar and 20Ne/36Ar do not show obvious differences between SF and SW. The concentration of the SF component in Kapoeta pyroxenes is approximately 20% that of the SW component, which is orders of magnitude higher than expected from SW and SF proton flux measurements. Variations in elemental and isotopic composition of He, Ne and Ar in SF relative to SW are found to correlate well with a (Z/A)2 dependence, indicating a rigidity-dependent particle spectrum in solar flares.

  3. Light noble gases in Jilin: More of the same and something new

    NASA Astrophysics Data System (ADS)

    Begemann, F.; Fan, Caiyun; Weber, H. W.; Wang, Xianbin

    1996-09-01

    Results are reported for documented samples from two drill cores and for specimens from the strewn field of the largest known stone meteorite, the H chondrite Jilin. Core B was found to have been parallel to the surface of Jilin during its first stage of irradiation, in 2π geometry. Core A was normal to the 2π surface; in it the mean attenuation length for the production by galactic cosmic rays of 38Ar from metal and of 21Ne from Mg, Al, Si in silicates was found to be the same. A numerical value for the mean attenuation length of (71 ± 4) cm or (246 ± 14) g × cm-2 follows if corrections for the contribution from the second stage of exposure are based on T2 = 0.32 Ma; agreement with the lower values of ˜180 g × cm-2 obtained from lunar studies and target data requires T2 to be about twice as long. Previous results are confirmed that in specimens with high contents of stable spallogenic gases the ratio 21Nebulk/38Armetal is low. The suggestion had been, and is, mat this is a transition effect in near-surface samples where the secondary cascade of nuclear-active particles, and hence the production of 21Ne, was not yet fully developed. This suggestion is borne out by the present results on two samples that, based on cosmic-ray tracks and 60Co content, are certified near-surface samples (although, strictly speaking, this is true only for the depth of burial during the second stage of irradiation). Cosmic-ray produced 60Co is positively correlated with 4He content, indicating that significant losses of 4He occurred when the Jilin meteoroid had acquired already its final size and shape and that the losses were more severe for near-surface samples than for such from the 4π interior. Presumably, the losses were caused by a thermal spike associated with the excavation of Jilin from its parent body. The same event caused losses of part of the 3He produced during the first irradiation stage. From the systematics of the 3He/21Ne vs. 4He correlation, we derive for the

  4. Solubility and Partitioning of Noble Gases in Anorthite, Diopside, Forsterite, Spinel, and Synthetic Basaltic Melts: Implications for the Origin and Evolution of Terrestrial Planet Atmospheres.

    NASA Astrophysics Data System (ADS)

    Broadhurst, Catherine Leigh

    The noble gas abundances and isotopic ratios of the terrestrial planets differ from each other and from the average of chondritic meteorites. These different abundance patterns result from primordial heterogeneities or different degassing histories. Magmatic transport is the only degassing mechanism that can be demonstrated to occur on Venus, Earth, and Mars, and is presently the dominant form of volatile transport to a planet's free surface. An alternative technique was developed to determine the partitioning and solubility of noble gases in mineral/melt systems. Natural end member minerals and synthetic melts known to be in equilibrium were held in separate crucibles in a one bar flowing noble gas atmosphere. Experiments were run 7-18 days at 1300 or 1332^circ C, in 99.95% Ar or a Ne-Ar-Kr-Xe mix. Gas concentrations were measured by mass spectrometry. The solubility of noble gases in minerals was surprisingly high, and individual samples of a particular mineral composition are distinct in their behavior. The data is consistent with lattice vacancy defect siting. Noble gas solubility in the minerals increases with increasing atomic number; this may be related to polarizability. Noble gas solubilities in melts decrease with increasing atomic number. Solubility is directly proportional to melt molar volume; values overlap the lower end of the range defined for natural basalts. The lower solubilities are related to the higher MgO and CaO concentrations and lower degree of polymerization and Fe^{3+ } concentration in synthetic vs. natural melts. Partition coefficient patterns show a clear trend of increasing compatibility with increasing noble gas atomic number, but many individual values are >1. Calculations show that the terrestrial planet atmospheres cannot have formed from partial melting of a common chondritic source. When results are examined with isotopic constraints and MOR and hot-spot activities, there is no compelling evidence that the Earth is

  5. Diffusive fractionation of noble gases in mantle with magma channels: Origin of low He/Ar in mantle-derived rocks

    NASA Astrophysics Data System (ADS)

    Yamamoto, Junji; Nishimura, Koshi; Sugimoto, Takeshi; Takemura, Keiji; Takahata, Naoto; Sano, Yuji

    2009-04-01

    By crushing olivine and pyroxene phenocrysts in volcanic rocks from Kyushu Island, Japan, we determined 3He/ 4He of 3-7 Ra and 40Ar/ 36Ar of up to 1750. These values are lower than those of MORB. 4He/ 40Ar* (down to 0.1) is much lower than the production ratio of 4He/ 40Ar* (1-5), where an asterisk denotes correction for the atmospheric contribution. Such values are typical of mantle-derived samples from the island arcs and active continental margins. Although the origin of the low 3He/ 4He and 40Ar/ 36Ar of subcontinental mantle has been widely discussed, low 4He/ 40Ar* has been given little attention. Actually, 3He/ 4He and 4He/ 40Ar* of phenocrysts overlap with those of subcontinental mantle xenoliths. Although noble gas compositions of phenocrysts are affected considerably by diffusive fractionation in ascending magma, they have little effect on the noble gases in the mantle xenoliths because it takes 100 years for He/Ar fractionation of ca. 15% for a mantle xenolith with 5 cm diameter. Therefore, the low 4He/ 40Ar* of the mantle xenoliths is inferred to result from another kinetic fractionation in the mantle. During generation and migration of magma in the mantle, lighter noble gases diffuse rapidly out into the magma. This diffusive fractionation can explain low 4He/ 40Ar* and somewhat low 3He/ 4He in the residual mantle. Furthermore, the combination of the diffusive fractionation and subsequent radiogenic ingrowth explain the fact that data from subcontinental mantle xenoliths have extremely low 3He/ 4He and various 4He/ 40Ar*. Consequently, 4He/ 40Ar* and 3He/ 4He in mantle-derived materials are proposed as indicators of the degree of noble gas depletion of the source mantle.

  6. The solvation radius of silicate melts based on the solubility of noble gases and scaled particle theory

    SciTech Connect

    Ottonello, Giulio; Richet, Pascal

    2014-01-28

    The existing solubility data on noble gases in high-temperature silicate melts have been analyzed in terms of Scaling Particle Theory coupled with an ab initio assessment of the electronic, dispersive, and repulsive energy terms based on the Polarized Continuum Model (PCM). After a preliminary analysis of the role of the contracted Gaussian basis sets and theory level in reproducing appropriate static dipole polarizabilities in a vacuum, we have shown that the procedure returns Henry's law constants consistent with the values experimentally observed in water and benzene at T = 25 °C and P = 1 bar for the first four elements of the series. The static dielectric constant (ε) of the investigated silicate melts and its optical counterpart (ε{sup ∞}) were then resolved through the application of a modified form of the Clausius-Mossotti relation. Argon has been adopted as a probe to depict its high-T solubility in melts through an appropriate choice of the solvent diameter σ{sub s}, along the guidelines already used in the past for simple media such as water or benzene. The σ{sub s} obtained was consistent with a simple functional form based on the molecular volume of the solvent. The solubility calculations were then extended to He, Ne, and Kr, whose dispersive and repulsive coefficients are available from theory and we have shown that their ab initio Henry's constants at high T reproduce the observed increase with the static polarizability of the series element with reasonable accuracy. At room temperature (T = 25 °C) the calculated Henry's constants of He, Ne, Ar, and Kr in the various silicate media predict higher solubilities than simple extrapolations (i.e., Arrhenius plots) based on high-T experiments and give rise to smooth trends not appreciably affected by the static polarizabilities of the solutes. The present investigation opens new perspectives on a wider application of PCM theory which can be extended to materials of great industrial interest at

  7. Itqiy: A study of noble gases and oxygen isotopes including its terrestrial age and a comparison with Zaklodzie

    NASA Astrophysics Data System (ADS)

    Patzer, Andrea; Hill, Dolores H.; Boynton, William V.; Franke, Luitgard; Schultz, Ludolf; Jull, A. J. Timothy; McHargue, Lanny R.; Franchi, Ian A.

    2002-06-01

    We report noble gas, oxygen isotope, 14C and 10Be data of Itqiy as well as noble gas, 14C and 10Be results for Zaklodzie. Both samples have been recently classified as anomalous enstatite meteorites and have been compared in terms of their mineralogy and chemical composition. The composition of enstatite and kamacite and the occurrence of specific sulfide phases in Itqiy indicate it formed under similar reducing conditions to those postulated for enstatite chondrites. The new results now seem to point at a direct spatial link. The noble gas record of Itqiy exhibits the presence of a trapped subsolar component, which is diagnostic for petrologic types 4-6 among enstatite chondrites. The concentration of radiogenic 4He is very low in Itqiy and indicates a recent thermal event. Its 21Ne cosmic-ray exposure age is 30.1 ~ 3.0 Ma and matches the most common age range of enstatite chondrites (mostly EL6 chondrites) but not that of Zaklodzie. Itqiy's isotopic composition of oxygen is in good agreement with that observed in Zaklodzie as well as those found in enstatite meteorites suggesting an origin from a common oxygen pool. The noble gas results, on the other hand, give reason to believe that the origin and evolution of Itqiy and Zaklodzie are not directly connected. Itqiy's terrestrial age of 5800 ~ 500 years sheds crucial light on the uncertain circumstances of its recovery and proves that Itqiy is not a modern fall, whereas the 14C results from Zaklodzie suggest it hit Earth only recently.

  8. Searching for Indigenous Noble Gases in the Moon: Vacuum Crushing of Vesicular Basalt 15016 and Stepwise Heating of Anorthosites 60025, 60215 and 65315 Aliquots

    NASA Astrophysics Data System (ADS)

    Bekaert, D. V.; Avice, G.; Marty, B.; Gudipati, M. S.; Henderson, B. L.

    2015-12-01

    Despite extensive efforts during the last four decades, no primordial signature of lunar xenon has been found. In order to further investigate the possible occurrence of indigenous volatiles in the Moon, we have analysed the noble gas and nitrogen isotopic compositions in two different sets of samples. Vacuum crushing of highly vesicular (~50% by volume) basalt 15016 (3.4 b.y. old, 300 m.y. exposure age) releases large amounts of spallation-produced gases that overshadow any other component. Lunar anorthosites 60025, 60215 and 65315 have the lowest exposure duration (~2m.y.) among Apollo samples. Consequently, they contain only limited cosmogenic (e.g. 124,126Xe) and solar wind noble gases. Furthermore, anorthosite is poor in U and Pu, leading to negligible contribution of fissiogenic Xe isotopes. These properties make these samples ideal for searching for lunar primordial noble gases. As observed in previous studies [1-3], lunar anorthosite Xe presents an isotopic composition very close to that of terrestrial atmosphere, which has been previously attributed to "abnormal adsorption" of terrestrial Xe after sample return. This presumed atmospheric Xe contamination can only be removed by heating the samples at medium to high temperature under vacuum, and is therefore different from common adsorption. In order to investigate this abnormal adsorption, uncrushed gravels of lunar anorthosite were exposed to a neutral Xe-rich atmosphere. Infrared reflectance spectrometry of processed, and unprocessed, samples shows a shift in the anorthosite's peak of the former, possibly corresponding to chemical Xe bonding. This phenomenon could explain the difficulties met for forty years when investigating a lunar primordial xenon component in anorthosites. However, our high precision Xe isotope analysis shows a systematic trend toward depletion in the heavy Xe isotopes (134Xe and 136Xe) not seen before. This leads us to make a tantalising parallel between the indigenous component in

  9. Anionic chemistry of noble gases: formation of Mg-NG (NG = Xe, Kr, Ar) compounds under pressure.

    PubMed

    Miao, Mao-Sheng; Wang, Xiao-Li; Brgoch, Jakoah; Spera, Frank; Jackson, Matthew G; Kresse, Georg; Lin, Hai-Qing

    2015-11-11

    While often considered to be chemically inert, the reactivity of noble gas elements at elevated pressures is an important aspect of fundamental chemistry. The discovery of Xe oxidation transformed the doctrinal boundary of chemistry by showing that a complete electron shell is not inert to reaction. However, the reductive propensity, i.e., gaining electrons and forming anions, has not been proposed or examined for noble gas elements. In this work, we demonstrate, using first-principles electronic structure calculations coupled to an efficient structure prediction method, that Xe, Kr, and Ar can form thermodynamically stable compounds with Mg at high pressure (≥125, ≥250, and ≥250 GPa, respectively). The resulting compounds are metallic and the noble gas atoms are negatively charged, suggesting that chemical species with a completely filled shell can gain electrons, filling their outermost shell(s). Moreover, this work indicates that Mg2NG (NG = Xe, Kr, Ar) are high-pressure electrides with some of the electrons localized at interstitial sites enclosed by the surrounding atoms. Previous predictions showed that such electrides only form in Mg and its compounds at very high pressures (>500 GPa). These calculations also demonstrate strong chemical interactions between the Xe 5d orbitals and the quantized interstitial quasiatom (ISQ) orbitals, including the strong chemical bonding and electron transfer, revealing the chemical nature of the ISQ.

  10. Noble Gases in Alpine Gold: U/Th-He Dating and Excesses of Radiogenic He and AR

    NASA Astrophysics Data System (ADS)

    Eugster, O.; Hofmann, B.; Krahenbuhl, U.; Neuenschwander, J.

    1992-07-01

    quantity of trapped atmospheric noble gases we estimate atmospheric ^4He in the gold samples to be three to five orders of magnitude below the observed ^4He concentration. Placer gold is finely distributed in rock material and might be exposed to an alpha-particle irradiation from neighboring U/Th-rich minerals. An alternative He source are inclusions of U/Th-rich minerals, such as zircon, either within the gold material or mechanically worked into the spangles as they were part of the river detritus. Acknowledgement: We thank the Swiss NSF for their support. References: Diamond L.W. (1990) Am. J. of Science 290, 912-958. Schmid K. (1973) Schw. Min. Petr. Mitt. 53, 125-156. Table 1, which in the hard copy appears here, shows concentrations of He, Ne, and Ar (10^-8 cm^3 STP/g) and of K, Th, and U (ppm) in vein-type free gold, placer gold, and quartz. The ^3He and ^21Ne signals were below detection limits, that is ^4He/^3He in gold is >100'000. Average ^20Ne/^22Ne ratios in gold and quartz are 10.2 +- 0.2, that is about 4% larger than in the terrestrial atmosphere. Average ^36Ar/^38Ar = 5.2 +- 0.2 (within errors identical to ^36Ar/^38Ar in air). 1) Sample sizes 50-100 mg. 2) Radiogenic ^40Ar = ^40Ar-295.5 x ^36Ar. 3) Calculated from U/Th and ^40K decay.

  11. Gas transport below artificial recharge ponds: insights from dissolved noble gases and a dual gas (SF6 and 3He) tracer experiment.

    PubMed

    Clark, Jordan F; Hudson, G Bryant; Avisar, Dror

    2005-06-01

    A dual gas tracer experiment using sulfur hexafluoride (SF6) and an isotope of helium (3He) and measurements of dissolved noble gases was performed at the El Rio spreading grounds to examine gas transport and trapped air below an artificial recharge pond with a very high recharge rate (approximately 4 m day(-1)). Noble gas concentrations in the groundwater were greater than in surface water due to excess air formation showing that trapped air exists below the pond. Breakthrough curves of SF6 and 3He at two nearby production wells were very similar and suggest that nonequilibrium gas transfer was occurring between the percolating water and the trapped air. At one well screened between 50 and 90 m below ground, both tracers were detected after 5 days and reached a maximum at approximately 24 days. Despite the potential dilution caused by mixing within the production well, the maximum concentration was approximately 25% of the mean pond concentration. More than 50% of the SF6 recharged was recovered by the production wells during the 18 month long experiment. Our results demonstrate that at artificial recharge sites with high infiltration rates and moderately deep water tables, transport times between recharge locations and wells determined with gas tracer experiments are reliable.

  12. Noble Gases in Iddingsite from the Lafayette Meteorite: Evidence for Liquid Water on Mars in the Last Few Hundred Million Years

    NASA Technical Reports Server (NTRS)

    Swindle, T. D.; Treiman, A. H.; Lindstrom, D. J.; Brkland, M. K.; Cohen, B. A.; Grier, J. A.; Li, B.; Olson, E. K.

    2000-01-01

    We analyzed noble gases from 18 samples of weathering products ("iddingsite") from the Lafayette meteorite. Potassium-argon ages of 12 samples range from near zero to 670 +/- 91 Ma. These ages confirm the martian origin of the iddingsite, but it is not clear whether any or all of the ages represent iddingsite formation as opposed to later alteration or incorporation of martian atmospheric Ar-40. In any case, because iddingsite formation requires liquid water, this data requires the presence of liquid water near the surface of Mars at least as recently as 1300 Ma ago, and probably as recently as 650 Ma ago. Krypton and Xe analysis of a single 34 microg sample indicates the presence of fractionated martian atmosphere within the iddingsite. This also confirms the martian origin of the iddingsite. The mechanism of incorporation could either be through interaction with liquid water during iddingsite formation or a result of shock implantation of adsorbed atmospheric gas.

  13. Coexistence and interfacial properties of a triangle-well mimicking the Lennard-Jones fluid and a comparison with noble gases.

    PubMed

    Bárcenas, M; Reyes, Y; Romero-Martínez, A; Odriozola, G; Orea, P

    2015-02-21

    Coexistence and interfacial properties of a triangle-well (TW) fluid are obtained with the aim of mimicking the Lennard-Jones (LJ) potential and approach the properties of noble gases. For this purpose, the scope of the TW is varied to match vapor-liquid densities and surface tension. Surface tension and coexistence curves of TW systems with different ranges were calculated with replica exchange Monte Carlo and compared to those data previously reported in the literature for truncated and shifted (STS), truncated (ST), and full Lennard-Jones (full-LJ) potentials. We observed that the scope of the TW potential must be increased to approach the STS, ST, and full-LJ properties. In spite of the simplicity of TW expression, a remarkable agreement is found. Furthermore, the variable scope of the TW allows for a good match of the experimental data of argon and xenon.

  14. Using carbon and water isotopes and noble gases to assess the origin of methane in fresh water aquifers in the south of the Netherlands

    NASA Astrophysics Data System (ADS)

    Broers, Hans Peter; de Weert, Jasperien; Vonhof, Hubert; Janssen, Renee; Sueltenfuss, Juergen; Aeschbach-Hertig, Werner; Castelijns, Jeroen

    2015-04-01

    Groundwater in the Dutch subsurface is known to contain substantial concentrations of methane of which the origin is not always clear. The Dutch subsurface contains relatively high organic matter contents which makes a biogenic origin plausible, however few studies have used water and carbon isotopes to deduce the origin of methane. In relation to possible future exploitation of deep shale gas resources, it is now considered important to assess base line quality of fresh groundwater in overlying aquifers from which drinking water is produced. Therefore, we sampled the raw water of 41 large public supply well fields in the south of the Netherlands which represents a mixture of groundwater of different ages and used the a discrete travel time distribution model (DTTDM, Visser et al. 2013, WRR) in order to quantify the age distribution of the mixture. Measurements included major ion chemistry, 3H, 3He, 4He, 18O, 2H, 14C, 13C-DIC and 13C-CH4 and the full range of noble gases. 13C-CH4 measurements were carried out using a Picarro G2201-i CRDS analyser. The heavier noble gases enable the calculation of the Noble Gas Temperature (NGT) which characterizes the temperature of past recharge conditions. The 14C apparent age of each mixture was derived correcting for dead carbon sources and included carbonate dissolution and methanogenesis as the defining processes. The 13C-CH4 measurements showed a range of δ-values between -70 and -100‰, which give a clear indication for biogenic methane. No clear relations between 13C-CH4 and 13C-DIC or the 4He/CH4 ratio were observed. However, clear spatial patterns indicated that more depleted values are grouped in specific areas. The 13δCH4 values did not show a clear relation with the age distribution of the pumped water, even though a large range of age distributions was observed including old water with an age of > 25 k yrs. We believe that spatial differences in organic matter contents, origin of the geological deposits and/or the

  15. Origins of volatile elements (H, C, N, noble gases) on Earth and Mars in light of recent results from the ROSETTA cometary mission

    NASA Astrophysics Data System (ADS)

    Marty, Bernard; Avice, Guillaume; Sano, Yuji; Altwegg, Kathrin; Balsiger, Hans; Hässig, Myrtha; Morbidelli, Alessandro; Mousis, Olivier; Rubin, Martin

    2016-05-01

    Recent measurements of the volatile composition of the coma of Comet 67P/Churyumov-Gerasimenko (hereafter 67P) allow constraints to be set on the origin of volatile elements (water, carbon, nitrogen, noble gases) in inner planets' atmospheres. Analyses by the ROSINA mass spectrometry system onboard the Rosetta spacecraft indicate that 67P ice has a D/H ratio three times that of the ocean value (Altwegg et al., 2015) and contains significant amounts of N2, CO, CO2, and importantly, argon (Balsiger et al., 2015). Here we establish a model of cometary composition based on literature data and the ROSINA measurements. From mass balance calculations, and provided that 67P is representative of the cometary ice reservoir, we conclude that the contribution of cometary volatiles to the Earth's inventory was minor for water (≤1%), carbon (≤1%), and nitrogen species (a few % at most). However, cometary contributions to the terrestrial atmosphere may have been significant for the noble gases. They could have taken place towards the end of the main building stages of the Earth, after the Moon-forming impact and during either a late veneer episode or, more probably, the Terrestrial Late Heavy Bombardment around 4.0-3.8 billion years (Ga) ago. Contributions from the outer solar system via cometary bodies could account for the dichotomy of the noble gas isotope compositions, in particular xenon, between the mantle and the atmosphere. A mass balance based on 36Ar and organics suggests that the amount of prebiotic material delivered by comets could have been quite considerable - equivalent to the present-day mass of the biosphere. On Mars, several of the isotopic signatures of surface volatiles (notably the high D/H ratios) are clearly indicative of atmospheric escape processes. Nevertheless, we suggest that cometary contributions after the major atmospheric escape events, e.g., during a Martian Late Heavy Bombardment towards the end of the Noachian era, could account for the

  16. Origin and Processes Highlighted By Noble Gases Geochemistry of Submarine Gas Emissions from Seeps at the Aquitaine Shelf (Bay of Biscay):

    NASA Astrophysics Data System (ADS)

    Battani, A.; Ruffine, L.; Donval, J. P.; Bignon, L.; Pujol, M.; Levaché, D.

    2014-12-01

    Noble gases are widely used as tracers to both determine fluid origin and identify transfer processes governing fluid flow in natural systems. This work presents the preliminary results and interpretations from submarine gas samples collected during the GAZCOGNE2 cruise (2013). The seepage activity and the spatial distribution of the widespread emission sites encountered at this area are described by (Dupré et al. 2014). Gas composition shows that methane is the dominant species compared to the C2+. The associated δ13C and δD signatures point to a biogenic origin- through CO2 reduction- of the gas. Helium concentrations are very low, ranging from 0.1 and 2.3 ppm, indicating a low residence time of the fluids in the subsurface. However, the resulting helium isotopic ratios are mostly crustal fingerprinted (around 0.02). The R/Ra values sometimes exhibit higher value of 0.2, indicative either an ASW (air saturated water) value, or the fingerprint of ancient mantle helium, the later in agreement with the geological structural context of the Parentis Basin. Most of the samples exhibit a mixing between ASW and air, probably by excess air addition to the initial ASW concentration. The elemental Ne/Ar ratio is remarkably constant for the totality of the samples, with a value typical of ASW (0.2). This result implies that the migrating gas phase is "stripping" the original water matrix from its noble gas content, as described by Gillfillian et al., 2008. This further indicates that an intermediate reservoir of biogenic gas should be present at depth. The GAZCOGNE study is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. References: Dupré, S., L. Berger, N. Le Bouffant, C. Scalabrin, and J. F. Bourillet (2014), Fluid emissions at the Aquitaine Shelf (Bay of Biscay, France): a biogenic origin or the expression of hydrocarbon leakage?, Continental Shelf Research, doi:10.1016/j.csr.2014.07.004. Gilfillan S

  17. On the size and structure of helium snowballs formed around charged atoms and clusters of noble gases.

    PubMed

    Bartl, Peter; Leidlmair, Christian; Denifl, Stephan; Scheier, Paul; Echt, Olof

    2014-09-18

    Helium nanodroplets doped with argon, krypton, or xenon are ionized by electrons and analyzed in a mass spectrometer. HenNgx(+) ions containing up to seven noble gas (Ng) atoms and dozens of helium atoms are identified; the high resolution of the mass spectrometer combined with advanced data analysis make it possible to unscramble contributions from isotopologues that have the same nominal mass but different numbers of helium or Ng atoms, such as the magic He20(84)Kr2(+) and the isobaric, nonmagic He41(84)Kr(+). Anomalies in these ion abundances reveal particularly stable ions; several intriguing patterns emerge. Perhaps most astounding are the results for HenAr(+), which show evidence for three distinct, solid-like solvation shells containing 12, 20, and 12 helium atoms. This observation runs counter to the common notion that only the first solvation shell is solid-like but agrees with calculations by Galli et al. for HenNa(+) [J. Phys. Chem. A 2011, 115, 7300] that reveal three shells of icosahedral symmetry. HenArx(+) (2 ≤ x ≤ 7) ions appear to be especially stable if they contain a total of n + x = 19 atoms. A sequence of anomalies in the abundance distribution of HenKrx(+) suggests that rings of six helium atoms are inserted into the solvation shell each time a krypton atom is added to the ionic core, from Kr(+) to Kr3(+). Previously reported strong anomalies at He12Kr2(+) and He12Kr3(+) [Kim , J. H.; et al. J. Chem. Phys. 2006, 124, 214301] are attributed to a contamination. Only minor local anomalies appear in the distributions of HenXex(+) (x ≤ 3). The distributions of HenKr(+) and HenXe(+) show strikingly similar, broad features that are absent from the distribution of HenAr(+); differences are tentatively ascribed to the very different fragmentation dynamics of these ions.

  18. The evolution of Devonian hydrocarbon gases in shallow aquifers of the northern Appalachian Basin: Insights from integrating noble gas and hydrocarbon geochemistry

    NASA Astrophysics Data System (ADS)

    Darrah, Thomas H.; Jackson, Robert B.; Vengosh, Avner; Warner, Nathaniel R.; Whyte, Colin J.; Walsh, Talor B.; Kondash, Andrew J.; Poreda, Robert J.

    2015-12-01

    groundwater (P(CH4) = ∼1 atmosphere) and elevated [Cl] and [Ba]. These data suggest that 4He is dominated by an exogenous (i.e., migrated) crustal source for these hydrocarbon gas- and salt-rich fluids. In combination with published inorganic geochemistry (e.g., 87Sr/86Sr, Sr/Ba, Br-/Cl-), new noble gas and hydrocarbon isotopic data (e.g., 20Ne/36Ar, C2+/C1, δ13C-CH4) suggest that a hydrocarbon-rich brine likely migrated from the Marcellus Formation (via primary hydrocarbon migration) as a dual-phase fluid (gas + liquid) and was fractionated by solubility partitioning during fluid migration and emplacement into conventional UD traps (via secondary hydrocarbon migration). Based on the highly fractionated 4He/CH4 data relative to Marcellus and UD production gases, we propose an additional phase of hydrocarbon gas migration where natural gas previously emplaced in UD hydrocarbon traps actively diffuses out into and equilibrates with modern shallow groundwater (via tertiary hydrocarbon migration) following uplift, denudation, and neotectonic fracturing. These data suggest that by integrating noble gas geochemistry with hydrocarbon and dissolved ion chemistry, one can better determine the source and migration processes of natural gas in the Earth's crust, which are two critical factors for understanding the presence of hydrocarbon gases in shallow aquifers.

  19. Adsorption of inert gases including element 118 on noble metal and inert surfaces from ab initio Dirac-Coulomb atomic calculations.

    PubMed

    Pershina, V; Borschevsky, A; Eliav, E; Kaldor, U

    2008-10-14

    The interaction of the inert gases Rn and element 118 with various surfaces has been studied on the basis of fully relativistic ab initio Dirac-Coulomb CCSD(T) calculations of atomic properties. The calculated polarizability of element 118, 46.3 a.u., is the largest in group 18, the ionization potential is the lowest at 8.91 eV, and the estimated atomic radius is the largest, 4.55 a.u. These extreme values reflect, in addition to the general trends in the Periodic Table, the relativistic expansion and destabilization of the outer valence 7p(3/2) orbital. Van der Waals coefficients C(3) and adsorption enthalpies DeltaH(ads) of Ne through element 118 on noble metals and inert surfaces, such as quartz, ice, Teflon, and graphite, were calculated in a physisorption model using the atomic properties obtained. The C(3) coefficients were shown to steadily increase in group 18, while the increase in DeltaH(ads) from Ne to Rn does not continue to element 118: The large atomic radius of the latter element is responsible for a decrease in the interaction energy. We therefore predict that experimental distinction between Rn and 118 by adsorption on these types of surfaces will not be feasible. A possible candidate for separating the two elements is charcoal; further study is needed to test this possibility.

  20. Noble gases in oxidized residue prepared from the Saratov L4 chondrite and Raman spectroscopic study of residues to characterize phase Q

    NASA Astrophysics Data System (ADS)

    Matsuda, Jun-Ichi; Morishita, Kazuhiko; Nara, Masayuki; Amari, Sachiko

    2016-01-01

    We analyzed noble gases in an oxidized residue prepared from a HF-HCl residue of the Saratov L4 chondrite. The Ar, Kr, and Xe concentrations in the oxidized residue are two orders of magnitude lower than those in the HF-HCl residue, and they are close to concentrations in the bulk. The He and Ne concentrations are similar in the three samples. The Ne isotopic ratios are almost purely cosmogenic, indicating absence of presolar diamonds (the carrier of the HL component). Thus, Saratov contains phase Q without presolar diamond. A study of the Raman spectroscopic parameters for the HF-HCl residue and the oxidized residue shows large changes due to oxidation. The directions of these changes are the same as observed in Allende, except oxidation increased the ID/IG (intensity ratio of the D band to the G band) in Saratov but decreased in Allende. This difference may be attributed to the different crystalline stages of carbon in both meteorites. The shifts in the Raman parameters to a discrete and/or more expanded region suggest that (1) oxidation changes the crystalline condition of graphitic carbon, (2) phase Q is not a dissolved site, and (3) the release of Q-gas is simply related to the rearrangement of the carbon structure during oxidation.

  1. Thermal metamorphism of primitive meteorites. VIII - Noble gases, carbon and sulfur in Allende /C3/ meteorite heated at 400-1000 C

    NASA Technical Reports Server (NTRS)

    Herzog, G. F.; Gibson, E. K., Jr.; Lipschutz, M. E.

    1979-01-01

    Noble gases, C and S, are lost from Allende samples heated for 1 week at temperatures of 400-1000 C in a low pressure environment. In the extreme, losses of He-3 and He-4 are about 100 x while for C, S and Ne, Ar and Kr isotopes and Xe-132 these are less than or equal to 10 x. Except for He, these losses are less severe than those of Bi or Tl from samples heated in the same runs. Significant He, Ne and Ar isotopic fractionation during heating indicates preferential outgassing of specific reservoirs. Next to He, Ar-40 is the most labile of those species considered here but still less so than Bi or Tl. L-group (but not H- or LL-group) chondrites may have lost mobile elements like Tl while being outgassed after late impact-associated heating. A less likely alternative involving a collateral relation between condensation conditions and depth in a parent object may also explain the L-group trend.

  2. Catching the role of anisotropic electronic distribution and charge transfer in halogen bonded complexes of noble gases

    SciTech Connect

    Bartocci, Alessio; Cappelletti, David; Pirani, Fernando; Belpassi, Leonardo; Falcinelli, Stefano; Grandinetti, Felice; Tarantelli, Francesco

    2015-05-14

    The systems studied in this work are gas-phase weakly bound adducts of the noble-gas (Ng) atoms with CCl{sub 4} and CF{sub 4}. Their investigation was motivated by the widespread current interest for the intermolecular halogen bonding (XB), a structural motif recognized to play a role in fields ranging from elementary processes to biochemistry. The simulation of the static and dynamic behaviors of complex systems featuring XB requires the formulation of reliable and accurate model potentials, whose development relies on the detailed characterization of strength and nature of the interactions occurring in simple exemplary halogenated systems. We thus selected the prototypical Ng-CCl{sub 4} and Ng-CF{sub 4} and performed high-resolution molecular beam scattering experiments to measure the absolute scale of their intermolecular potentials, with high sensitivity. In general, we expected to probe typical van der Waals interactions, consisting of a combination of size (exchange) repulsion with dispersion/induction attraction. For the He/Ne-CF{sub 4}, the analysis of the glory quantum interference pattern, observable in the velocity dependence of the integral cross section, confirmed indeed this expectation. On the other hand, for the He/Ne/Ar-CCl{sub 4}, the scattering data unravelled much deeper potential wells, particularly for certain configurations of the interacting partners. The experimental data can be properly reproduced only including a shifting of the repulsive wall at shorter distances, accompanied by an increased role of the dispersion attraction, and an additional short-range stabilization component. To put these findings on a firmer ground, we performed, for selected geometries of the interacting complexes, accurate theoretical calculations aimed to evaluate the intermolecular interaction and the effects of the complex formation on the electron charge density of the constituting moieties. It was thus ascertained that the adjustments of the potential

  3. Catching the role of anisotropic electronic distribution and charge transfer in halogen bonded complexes of noble gases

    NASA Astrophysics Data System (ADS)

    Bartocci, Alessio; Belpassi, Leonardo; Cappelletti, David; Falcinelli, Stefano; Grandinetti, Felice; Tarantelli, Francesco; Pirani, Fernando

    2015-05-01

    The systems studied in this work are gas-phase weakly bound adducts of the noble-gas (Ng) atoms with CCl4 and CF4. Their investigation was motivated by the widespread current interest for the intermolecular halogen bonding (XB), a structural motif recognized to play a role in fields ranging from elementary processes to biochemistry. The simulation of the static and dynamic behaviors of complex systems featuring XB requires the formulation of reliable and accurate model potentials, whose development relies on the detailed characterization of strength and nature of the interactions occurring in simple exemplary halogenated systems. We thus selected the prototypical Ng-CCl4 and Ng-CF4 and performed high-resolution molecular beam scattering experiments to measure the absolute scale of their intermolecular potentials, with high sensitivity. In general, we expected to probe typical van der Waals interactions, consisting of a combination of size (exchange) repulsion with dispersion/induction attraction. For the He/Ne-CF4, the analysis of the glory quantum interference pattern, observable in the velocity dependence of the integral cross section, confirmed indeed this expectation. On the other hand, for the He/Ne/Ar-CCl4, the scattering data unravelled much deeper potential wells, particularly for certain configurations of the interacting partners. The experimental data can be properly reproduced only including a shifting of the repulsive wall at shorter distances, accompanied by an increased role of the dispersion attraction, and an additional short-range stabilization component. To put these findings on a firmer ground, we performed, for selected geometries of the interacting complexes, accurate theoretical calculations aimed to evaluate the intermolecular interaction and the effects of the complex formation on the electron charge density of the constituting moieties. It was thus ascertained that the adjustments of the potential suggested by the analysis of the

  4. Basin scale natural gas source, migration and trapping traced by noble gases and major elements: the Pakistan Indus basin

    NASA Astrophysics Data System (ADS)

    Battani, Anne; Sarda, Philippe; Prinzhofer, Alain

    2000-08-01

    He, Ne and Ar concentrations, He and Ar isotopic ratios, carbon isotopic ratios and chemical compositions of hydrocarbon gases were measured in natural gas samples from gas-producing wells in the Indus basin, Pakistan, where no oil has ever been found. 3He/ 4He ratios are in the range 0.01-0.06 Ra (Ra is the atmospheric value of 1.38×10 -6) indicating the absence of mantle-derived helium despite the Trias extension. 40Ar/ 36Ar ratios range from 296 to 800, consistent with variable additions of radiogenic argon to atmospheric, groundwater-derived argon. Rare gas concentrations show large variations, from 6×10 -5 to 1×10 -3 mol/mol for 4He and from 3×10 -7 to 3×10 -5 mol/mol for 36Ar. In general, 36Ar concentrations are high compared to literature data for natural gas. CO 2 and N 2 concentrations are variable, ranging up to 70 and 20%, respectively. Mantle-derived He is not observed, therefore CO 2 and N 2 are not mantle-derived either. Hydrocarbon gas maturity is high, but accumulation efficiency is small, suggesting that early-produced hydrocarbons, including oil, were lost as well as mantle helium. This is consistent with the generally late, Pliocene, trap formation, and explains the high N 2 concentrations, since N 2 is the final species generated at the end of organic matter maturation. Based on δ 13C data, CO 2 originates from carbonate decomposition. Very elevated 20Ne/ 36Ar ratios are found, reaching a maximum of 1.3 (compared to 0.1-0.2 for air-saturated water and 0.5 for air), and these high values are related to the lowest rare gas concentrations. We suggest that this highly fractionated signature is the trace of the past presence of oil in the basin and appeared in groundwater. We propose a model where oil-water contact is followed by gas-water contact, both with Rayleigh distillation for rare gas abundance ratios, thereby generating the fractionated 20Ne/ 36Ar signature in groundwater first and transferring it to gas later. Assuming the gas

  5. Noble gas trapping by laboratory carbon condensates

    NASA Technical Reports Server (NTRS)

    Niemeyer, S.; Marti, K.

    1982-01-01

    Trapping of noble gases by carbon-rich matter was investigated by synthesizing carbon condensates in a noble gas atmosphere. Laser evaporation of a solid carbon target yielded submicron grains which proved to be efficient noble gas trappers (Xe distribution coefficients up to 13 cu cm STP/g-atm). The carbon condensates are better noble gas trappers than previously reported synthetic samples, except one, but coefficients inferred for meteoritic acid-residues are still orders of magnitude higher. The trapped noble gases are loosely bound and elementally strongly fractionated, but isotopic fractionations were not detected. Although this experiment does not simulate nebular conditions, the results support the evidence that carbon-rich phases in meteorites may be carriers of noble gases from early solar system reservoirs. The trapped elemental noble gas fractionations are remarkably similar to both those inferred for meteorites and those of planetary atmospheres for earth, Mars and Venus.

  6. Revealing the magmas degassing below closed-conduit active volcanoes: noble gases in volcanic rocks versus fumarolic fluids at Vulcano (Aeolian Islands, Italy)

    NASA Astrophysics Data System (ADS)

    Mandarano, Michela; Paonita, Antonio; Martelli, Mauro; Viccaro, Marco; Nicotra, Eugenio; Millar, Ian L.

    2016-04-01

    With the aim to constrain the nature of magma currently feeding the fumarolic field of Vulcano, we measured the elemental and isotopic compositions of noble gases (He, Ne, and Ar) in olivine- and clinopyroxene-hosted fluid inclusions in high-K calcalcaline-shoshonitic and shoshonitic-potassic series so as to cover the entire volcanological history of Vulcano Island (Italy). The major and trace-element concentrations and the Sr- and Pb-isotope compositions for whole rocks were integrated with data obtained from the fluid inclusions. 3He/4He in fluid inclusions is within the range of 3.30 and 5.94 R/Ra, being lower than the value for the deep magmatic source expected for Vulcano Island (6.0-6.2 R/Ra). 3He/4He of the magmatic source is almost constant throughout the volcanic record of Vulcano. Integration of the He- and Sr-isotope systematics leads to the conclusion that a decrease in the He-isotope ratio of the rocks is mainly due to the assimilation of 10-25% of a crustal component similar to the Calabrian basement. 3He/4He shows a negative correlation with Sr isotopes except for the last-emitted Vulcanello latites (Punta del Roveto), which have high He- and Sr-isotope ratios. This anomaly has been attributed to a flushing process by fluids coming from the deepest reservoirs. Indeed, an input of deep magmatic volatiles with high 3He/4He values increases the He-isotope ratio without changing 87Sr/86Sr. A comparison of the He isotope ratios between fluid inclusions and fumarolic gases showed that only the basalts of La Sommata and the latites of Vulcanello have comparable values. Taking into account that the latites of Vulcanello relate to one of the most-recent eruptions at Vulcano (in the 17th century), we infer that that the most probable magma which actually feeds the fumarolic emissions is a latitic body ponding at about 3-3.5 km of depth and flushed by fluids coming from a deeper and basic magma.

  7. Using noble gases measured in spring discharge to trace hydrothermal processes in the Norris Geyser Basin, Yellowstone National Park, U.S.A.

    USGS Publications Warehouse

    Gardner, W.P.; Susong, D.D.; Solomon, D.K.; Heasler, H.P.

    2010-01-01

    Dissolved noble gas concentrations in springs are used to investigate boiling of hydrothermal water and mixing of hydrothermal and shallow cool water in the Norris Geyser Basin area. Noble gas concentrations in water are modeled for single stage and continuous steam removal. Limitations on boiling using noble gas concentrations are then used to estimate the isotopic effect of boiling on hydrothermal water, allowing the isotopic composition of the parent hydrothermal water to be determined from that measured in spring. In neutral chloride springs of the Norris Geyser Basin, steam loss since the last addition of noble gas charged water is less than 30% of the total hydrothermal discharge, which results in an isotopic shift due to boiling of ?? 2.5% ??D. Noble gas concentrations in water rapidly and predictably change in dual phase systems, making them invaluable tracers of gas-liquid interaction in hydrothermal systems. By combining traditional tracers of hydrothermal flow such as deuterium with dissolved noble gas measurements, more complex hydrothermal processes can be interpreted. ?? 2010 Elsevier B.V.

  8. Nitrogen and noble gases in the 71501 bulk soil and ilmenite as records of the solar wind exposure: Which is correct?

    NASA Technical Reports Server (NTRS)

    Signer, P.; Baur, H.; Etique, P.; Wieler, R.

    1986-01-01

    The N determination in mg sized mineral separates from lunar soils by static mass spectrometry is an experimental break-through likely to contribute to the deciphering of the records left in the mineral grains by the exposure to the solar wind. In this discussion some comparisons of the results of N and noble gas analyses of the 71501 bulk soil and an ilmenite separate thereof are focussed on. Conclusions from noble gas data obtained on mineral separates from some 20 soils are summarized in a companion paper and are also discussed herein.

  9. Cosmogenic noble gas paleothermometry

    NASA Astrophysics Data System (ADS)

    Tremblay, Marissa M.; Shuster, David L.; Balco, Greg

    2014-08-01

    We present a theoretical basis for reconstructing paleotemperatures from the open-system behavior of cosmogenic noble gases produced in minerals at Earth's surface. Experimentally-determined diffusion kinetics predicts diffusive loss of cosmogenic 3He and 21Ne from common minerals like quartz and feldspars at ambient temperatures; incomplete retention has also been observed empirically in field studies. We show that the theory of simultaneous production and diffusion that applies to radiogenic noble gases in minerals-the basis of thermochronology-can also be applied to cosmogenic noble gases to reconstruct past surface temperatures on Earth. We use published diffusion kinetics and production rates for 3He in quartz and 21Ne in orthoclase to demonstrate the resolving power of cosmogenic noble gas paleothermometry with respect to exposure duration, temperature, and diffusion domain size. Calculations indicate that, when paired with a quantitatively retained cosmogenic nuclide such as 21Ne or 10Be, observations of cosmogenic 3He in quartz can constrain temperatures during surface exposure in polar and high altitude environments. Likewise, 21Ne retention in feldspars is sensitive to temperatures at lower latitudes and elevations, expanding the potential geographic applicability of this technique to most latitudes. As an example, we present paired measurements of 3He and 10Be in quartz from a suite of Antarctic sandstone erratics to test whether the abundances of cosmogenic 3He agree with what is predicted from first principles and laboratory-determined diffusion kinetics. We find that the amounts of cosmogenic 3He present in these samples are consistent with the known mean annual temperature (MAT) for this region of Antarctica between -25 and -30 °C. These results demonstrate the method's ability to record paleotemperatures through geologic time.

  10. Noble Gas Temperature Proxy for Climate Change

    EPA Science Inventory

    Noble gases in groundwater appear to offer a practical approach for quantitatively determining past surface air temperatures over recharge areas for any watershed. The noble gas temperature (NGT) proxy should then permit a paleothermometry of a region over time. This terrestria...

  11. Transferability and accuracy by combining dispersionless density functional and incremental post-Hartree-Fock theories: Noble gases adsorption on coronene/graphene/graphite surfaces

    SciTech Connect

    Lara-Castells, María Pilar de Bartolomei, Massimiliano; Mitrushchenkov, Alexander O.; Stoll, Hermann

    2015-11-21

    The accuracy and transferability of the electronic structure approach combining dispersionless density functional theory (DFT) [K. Pernal et al., Phys. Rev. Lett. 103, 263201 (2009)] with the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)], are validated for the interaction between the noble-gas Ne, Ar, Kr, and Xe atoms and coronene/graphene/graphite surfaces. This approach uses the method of increments for surface cluster models to extract intermonomer dispersion-like (2- and 3-body) correlation terms at coupled cluster singles and doubles and perturbative triples level, while periodic dispersionless density functionals calculations are performed to estimate the sum of Hartree-Fock and intramonomer correlation contributions. Dispersion energy contributions are also obtained using DFT-based symmetry-adapted perturbation theory [SAPT(DFT)]. An analysis of the structure of the X/surface (X = Ne, Ar, Kr, and Xe) interaction energies shows the excellent transferability properties of the leading intermonomer correlation contributions across the sequence of noble-gas atoms, which are also discussed using the Drude oscillator model. We further compare these results with van der Waals-(vdW)-corrected DFT-based approaches. As a test of accuracy, the energies of the low-lying nuclear bound states supported by the laterally averaged X/graphite potentials (X = {sup 3}He, {sup 4}He, Ne, Ar, Kr, and Xe) are calculated and compared with the best estimations from experimental measurements and an atom-bond potential model using the ab initio-assisted fine-tuning of semiempirical parameters. The bound-state energies determined differ by less than 6–7 meV (6%) from the atom-bond potential model. The crucial importance of including incremental 3-body dispersion-type terms is clearly demonstrated, showing that the SAPT(DFT) approach effectively account for these terms. With the deviations from the best experimental-based estimations smaller than 2.3 meV (1.9%), the

  12. Transferability and accuracy by combining dispersionless density functional and incremental post-Hartree-Fock theories: Noble gases adsorption on coronene/graphene/graphite surfaces

    NASA Astrophysics Data System (ADS)

    de Lara-Castells, María Pilar; Bartolomei, Massimiliano; Mitrushchenkov, Alexander O.; Stoll, Hermann

    2015-11-01

    The accuracy and transferability of the electronic structure approach combining dispersionless density functional theory (DFT) [K. Pernal et al., Phys. Rev. Lett. 103, 263201 (2009)] with the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)], are validated for the interaction between the noble-gas Ne, Ar, Kr, and Xe atoms and coronene/graphene/graphite surfaces. This approach uses the method of increments for surface cluster models to extract intermonomer dispersion-like (2- and 3-body) correlation terms at coupled cluster singles and doubles and perturbative triples level, while periodic dispersionless density functionals calculations are performed to estimate the sum of Hartree-Fock and intramonomer correlation contributions. Dispersion energy contributions are also obtained using DFT-based symmetry-adapted perturbation theory [SAPT(DFT)]. An analysis of the structure of the X/surface (X = Ne, Ar, Kr, and Xe) interaction energies shows the excellent transferability properties of the leading intermonomer correlation contributions across the sequence of noble-gas atoms, which are also discussed using the Drude oscillator model. We further compare these results with van der Waals-(vdW)-corrected DFT-based approaches. As a test of accuracy, the energies of the low-lying nuclear bound states supported by the laterally averaged X/graphite potentials (X = 3He, 4He, Ne, Ar, Kr, and Xe) are calculated and compared with the best estimations from experimental measurements and an atom-bond potential model using the ab initio-assisted fine-tuning of semiempirical parameters. The bound-state energies determined differ by less than 6-7 meV (6%) from the atom-bond potential model. The crucial importance of including incremental 3-body dispersion-type terms is clearly demonstrated, showing that the SAPT(DFT) approach effectively account for these terms. With the deviations from the best experimental-based estimations smaller than 2.3 meV (1.9%), the accuracy of the

  13. Transferability and accuracy by combining dispersionless density functional and incremental post-Hartree-Fock theories: Noble gases adsorption on coronene/graphene/graphite surfaces.

    PubMed

    de Lara-Castells, María Pilar; Bartolomei, Massimiliano; Mitrushchenkov, Alexander O; Stoll, Hermann

    2015-11-21

    The accuracy and transferability of the electronic structure approach combining dispersionless density functional theory (DFT) [K. Pernal et al., Phys. Rev. Lett. 103, 263201 (2009)] with the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)], are validated for the interaction between the noble-gas Ne, Ar, Kr, and Xe atoms and coronene/graphene/graphite surfaces. This approach uses the method of increments for surface cluster models to extract intermonomer dispersion-like (2- and 3-body) correlation terms at coupled cluster singles and doubles and perturbative triples level, while periodic dispersionless density functionals calculations are performed to estimate the sum of Hartree-Fock and intramonomer correlation contributions. Dispersion energy contributions are also obtained using DFT-based symmetry-adapted perturbation theory [SAPT(DFT)]. An analysis of the structure of the X/surface (X = Ne, Ar, Kr, and Xe) interaction energies shows the excellent transferability properties of the leading intermonomer correlation contributions across the sequence of noble-gas atoms, which are also discussed using the Drude oscillator model. We further compare these results with van der Waals-(vdW)-corrected DFT-based approaches. As a test of accuracy, the energies of the low-lying nuclear bound states supported by the laterally averaged X/graphite potentials (X = (3)He, (4)He, Ne, Ar, Kr, and Xe) are calculated and compared with the best estimations from experimental measurements and an atom-bond potential model using the ab initio-assisted fine-tuning of semiempirical parameters. The bound-state energies determined differ by less than 6-7 meV (6%) from the atom-bond potential model. The crucial importance of including incremental 3-body dispersion-type terms is clearly demonstrated, showing that the SAPT(DFT) approach effectively account for these terms. With the deviations from the best experimental-based estimations smaller than 2.3 meV (1.9%), the accuracy of

  14. Genesis Noble Gas Measurements

    NASA Technical Reports Server (NTRS)

    Hohenberg, Charles M.

    2005-01-01

    The original thrust of our Genesis funding was to extend and refine the noble gas analytical capabilities of this laboratory to improve the precision and accuracy of noble gas measurements in order to optimize the scientific return from the Genesis Mission. This process involved both instrumental improvement (supplemented by a SRLIDAP instrument grant) and refinement of technique. The Genesis landing mishap shifted our emphasis to the irregular aluminum heat shield material from the flat collector wafers. This has required redesign of our laser extraction cells to accommodate the longer focal lengths required for laser extraction from non-flat surfaces. Extraction of noble gases from solid aluminum surfaces, rather than thin coatings on transparent substrates has required refinement of controlled-depth laser ablation techniques. Both of these bring new problems, both with potentially higher blanks form larger laser cells and the larger quantities of evaporated aluminum which can coat the sapphire entrance ports. This is mainly a problem for the heavy noble gases where larger extraction areas are required, necessitating the new aluminum vapor containment techniques described below. With the Genesis Mission came three new multiple multiplier noble gas mass spectrometers to this laboratory, one built solely by us (Supergnome-M), one built in collaboration with Nu-Instruments (Noblesse), and one built in collaboration with GVI (Helix). All of these have multiple multiplier detection sections with the Nu-Instruments using a pair of electrostatic quad lenses for isotope spacing and the other two using mechanically adjustable positions for the electron multipliers. The Supergnome-M and Noblesse are installed and running. The GVI instrument was delivered a year late (in March 2005) and is yet to be installed by GVI. As with all new instruments there were some initial development issues, some of which are still outstanding. The most serious of these are performance issues

  15. Simulations of atmospheric pressure discharge in a high-voltage nanosecond pulse using the particle-in-cell Monte Carlo collision model in noble gases

    NASA Astrophysics Data System (ADS)

    Shi, Feng; Wang, Dezhen; Ren, Chunsheng

    2008-06-01

    Atmospheric pressure discharge nonequilibrium plasmas have been applied to plasma processing with modern technology. Simulations of discharge in pure Ar and pure He gases at one atmospheric pressure by a high voltage trapezoidal nanosecond pulse have been performed using a one-dimensional particle-in-cell Monte Carlo collision (PIC-MCC) model coupled with a renormalization and weighting procedure (mapping algorithm). Numerical results show that the characteristics of discharge in both inert gases are very similar. There exist the effects of local reverse field and double-peak distributions of charged particles' density. The electron and ion energy distribution functions are also observed, and the discharge is concluded in the view of ionization avalanche in number. Furthermore, the independence of total current density is a function of time, but not of position.

  16. Assessment of natural dynamics and anthropogenic impacts on residence times in the urban aquifers of Recife (Brazil) using a multi-tracer approach (noble gases, CFCs, SF6, 14C)

    NASA Astrophysics Data System (ADS)

    Chatton, Eliot; Labasque, Thierry; Aquilina, Luc; Petelet-Giraud, Emmanuelle; Cary, Lise; Bertrand, Guillaume; Hochreutener, Rébecca

    2015-04-01

    The Metropolitan Region of Recife (RMR) is an urban area of the northeastern coast of Brazil located in an estuary zone and overlying a complex multi-layered sedimentary set. Over the last decades, population growth and recurrent droughts have been increasing the pressures on the aquifers of the region (over-exploitation, contamination and salinization). Through a multi-tracer approach (major and noble gases, CFCs, SF6, 14C) and the implementation of an inverse model to infer recharge conditions, the study aims to investigate the past natural dynamics of the aquifer system and to assess the impacts of the increasing withdrawals on the residence times in the aquifers. Noble gas results were implemented in an inverse model allowing the assessment the recharge conditions of the coastal aquifers of Recife. The results allowed to discriminate two types of recharge in terms of temperature and excess air. The overexploited surficial aquifer records recharge characteristics of the modern wet seasons. However, groundwaters sampled in the two underlying aquifers (Cabo and Beberibe) showed recharge temperatures below the regional minima. According to the radiocarbon dating performed in this study and previous paleotemperature studies in tropical Brazil (Stute et al., 1995), it appears that the major component of the current water supply of Recife originates from recharges dating back more than 10,000 years. Furthermore, the analysis of atmospheric tracers (CFCs, SF6) show that the exploitation of these old groundwaters has lead to a mixing with a more recent component (<50 years old) making these aquifers vulnerable to contamination and salinization.

  17. Noble gases in 18 Martian meteorites and angrite Northwest Africa 7812—Exposure ages, trapped gases, and a re-evaluation of the evidence for solar cosmic ray-produced neon in shergottites and other achondrites

    NASA Astrophysics Data System (ADS)

    Wieler, R.; Huber, L.; Busemann, H.; Seiler, S.; Leya, I.; Maden, C.; Masarik, J.; Meier, M. M. M.; Nagao, K.; Trappitsch, R.; Irving, A. J.

    2016-02-01

    We present noble gas data for 16 shergottites, 2 nakhlites (NWA 5790, NWA 10153), and 1 angrite (NWA 7812). Noble gas exposure ages of the shergottites fall in the 1-6 Ma range found in previous studies. Three depleted olivine-phyric shergottites (Tissint, NWA 6162, NWA 7635) have exposure ages of ~1 Ma, in agreement with published data for similar specimens. The exposure age of NWA 10153 (~12.2 Ma) falls in the range of 9-13 Ma reported for other nakhlites. Our preferred age of ~7.3 Ma for NWA 5790 is lower than this range, and it is possible that NWA 5790 represents a distinct ejection event. A Tissint glass sample contains Xe from the Martian atmosphere. Several samples show a remarkably low (21Ne/22Ne)cos ratio < 0.80, as previously observed in a many shergottites and in various other rare achondrites. This was explained by solar cosmic ray-produced Ne (SCR Ne) in addition to the commonly found galactic cosmic ray-produced Ne, implying very low preatmospheric shielding and ablation loss. We revisit this by comparing measured (21Ne/22Ne)cos ratios with predictions by cosmogenic nuclide production models. Indeed, several shergottites, acalpulcoites/lodranites, angrites (including NWA 7812), and the Brachina-like meteorite LEW 88763 likely contain SCR Ne, as previously postulated for many of them. The SCR contribution may influence the calculation of exposure ages. One likely reason that SCR nuclides are predominantly detected in meteorites from rare classes is because they usually are analyzed for cosmogenic nuclides even if they had a very small (preatmospheric) mass and hence low ablation loss.

  18. The Thermochemical Stability of Ionic Noble Gas Compounds.

    ERIC Educational Resources Information Center

    Purser, Gordon H.

    1988-01-01

    Presents calculations that suggest stoichiometric, ionic, and noble gas-metal compounds may be stable. Bases calculations on estimated values of electron affinity, anionic radius for the noble gases and for the Born exponents of resulting crystals. Suggests the desirability of experiments designed to prepare compounds containing anionic,…

  19. Noble-gas-rich separates from the Allende meteorite

    NASA Technical Reports Server (NTRS)

    Ott, U.; Mack, R.; Chang, S.

    1981-01-01

    Predominantly carbonaceous HF/HCl-resistant residues from the Allende meteorite are studied. Samples are characterized by SEM/EDXA, X-ray diffraction, INAA, C, S, H, N, and noble gas analyses. Isotopic data for carbon show variations no greater than 5%, while isotopic data from noble gases confirm previously established systematics. Noble gas abundances correlate with those of C and N, and concomitant partial loss of C and normal trapped gas occur during treatments with oxidizing acids. HF/HCl demineralization of bulk meteorite results in similar fractional losses of C and trapped noble gases, which leads to the conclusion that various macromolecular carbonaceous substances serve as the main host phase for normal trapped noble gases and anomalous gases in acid-resistant residues, and as the carrier of the major part of trapped noble gases lost during HF/HCl demineralization. Limits on the possible abundances of dense mineralic host phases in the residues are obtained, and considerations of the nucleogenetic origin for CCF-XE indicate that carbonaceous host phases and various forms of organic matter in carbonaceous meteorites may have a presolar origin.

  20. Noble gas transport during devolatilization of oceanic crust

    NASA Astrophysics Data System (ADS)

    Jackson, C.; Smye, A.; Shuster, D. L.; Parman, S. W.; Kelley, S. P.; Hesse, M. A.; Cooper, R. F.

    2014-12-01

    Here we examine the role of slab dehydration in determining the elemental pattern of recycled noble gases. As a first step, we apply newly reported measurements of He-Ne-Ar (light noble gases) solubility and diffusivity in amphibole to parameterize a 1D diffusive-reaction transport model that simulates noble gas behavior during fluid loss from down-going oceanic crust. Recent experiments demonstrate that noble gases are highly soluble in ring-structured minerals, such as amphibole and other common hydrothermal products in slabs [1]. These results suggest that ring-structured minerals have the potential to strongly influence the budget of noble gases input into subduction zones and the elemental fractionations associated with volatile loss from slabs New measurements of He-Ne-Ar solubility in a suite of amphiboles have been completed utilizing the methodology described in [1]. These new measurements confirm that all light noble gases are highly soluble in amphibole, and that noble gas solubility correlates with the availability of unoccupied ring sites. New experimental measurements of He and Ne diffusivity have also been completed using a step-degassing approach at the Berkeley Geochronology Center. These measurements suggest that vacant ring sites in amphibole act to slow noble gas diffusion. We combine the newly acquired He and Ne diffusivity measurements with literature values for Ar diffusivity [2] to parameterize the diffusive-reaction transport model. Application of these data to the diffusive-reaction transport model yields several new insights. The relative mobility of Ne compared to Ar allows for efficient extraction of Ne from "hot" slabs by shallow depths (<50 km), while Ar is effectively retained to deeper depths, potentially past sub-arc conditions. Noble gas partition coefficients sharply increase with depth, following their increasing non-ideality in supercritical fluids, causing noble gases to partition back into minerals from any fluids retained in

  1. Noble gas fractionation during subsurface gas migration

    NASA Astrophysics Data System (ADS)

    Sathaye, Kiran J.; Larson, Toti E.; Hesse, Marc A.

    2016-09-01

    Environmental monitoring of shale gas production and geological carbon dioxide (CO2) storage requires identification of subsurface gas sources. Noble gases provide a powerful tool to distinguish different sources if the modifications of the gas composition during transport can be accounted for. Despite the recognition of compositional changes due to gas migration in the subsurface, the interpretation of geochemical data relies largely on zero-dimensional mixing and fractionation models. Here we present two-phase flow column experiments that demonstrate these changes. Water containing a dissolved noble gas is displaced by gas comprised of CO2 and argon. We observe a characteristic pattern of initial co-enrichment of noble gases from both phases in banks at the gas front, followed by a depletion of the dissolved noble gas. The enrichment of the co-injected noble gas is due to the dissolution of the more soluble major gas component, while the enrichment of the dissolved noble gas is due to stripping from the groundwater. These processes amount to chromatographic separations that occur during two-phase flow and can be predicted by the theory of gas injection. This theory provides a mechanistic basis for noble gas fractionation during gas migration and improves our ability to identify subsurface gas sources after post-genetic modification. Finally, we show that compositional changes due to two-phase flow can qualitatively explain the spatial compositional trends observed within the Bravo Dome natural CO2 reservoir and some regional compositional trends observed in drinking water wells overlying the Marcellus and Barnett shale regions. In both cases, only the migration of a gas with constant source composition is required, rather than multi-stage mixing and fractionation models previously proposed.

  2. Noble gas magnetic resonator

    DOEpatents

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2014-04-15

    Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.

  3. An Air Noble Gas Component in the Mantle

    NASA Astrophysics Data System (ADS)

    Sarda, P.

    2005-12-01

    Noble gas geochemistry has for long attempted to recover isotopic signatures of mantle components through analyses of basalt glass or xenoliths, but this quest has been plagued by the occurrence of a conspicuous air component, which appears to have both the isotopic and elemental composition of air (except for helium). It is classically considered to be air added to samples close to the surface, in a poorly understood process called "contamination", due to the interaction of rocks and melts with air or water on emplacement. Focusing on Mid-Ocean Ridge Basalts (and Ocean Island Basalts), gases are mostly borne by vesicles and a number of puzzling observations can be made: - vesicles appear to be heterogeneous at the scale of a centimeter, as shown by stepwise crushing experiments, some vesicles having air, some having mantle gases, some having mixtures of both, - vesicles appear over-pressured (P > 1 bar) in fresh samples, as shown by highly vesiculous samples such as Popping Rocks, - the air component appears to be borne by the largest vesicles, as it is recovered in the first steps of stepwise crushing analyses, - larger samples seem to have more of the air component than smaller ones, - in Popping Rocks, the air component borne by the largest vesicles is overwhelming, - the isotopic composition of Pb-Sr-Nd in Popping Rocks was interpreted as indicating a recycled component (related to the HIMU and EM1 mantle end-members). The air noble gas component was suggested recently to be not seawater, but modern air located in fractures of the glass, which should have opened on cooling and resealed immediately [1]. This model faces some difficulties, such as keeping pressure high in the vesicles. I suggest another interpretation, namely that a large part of the air noble gases in oceanic basalts is recycled in origin [2]. It would have been carried down into the mantle at subduction zones, even if most (typically 90%) of the air noble gases in the slab returns to the

  4. Noble Gas Proxy Evidence Of Holocene Climate Fluctuations In The Elwha Watershed, Olympic Mountains, Washington

    EPA Science Inventory

    Paleotempertures retrieved from the groundwater archives in the largest watershed (≈800 km2) in the Olympic Mountains suggest asynchronous Olympic Peninsula climate responses during the Everson interstade period after the last continental glacial maximum. Dissolved noble gases fr...

  5. Helium Isotopes and Noble Gas Abundances of Cave Dripping Water in Three Caves in East Asia

    NASA Astrophysics Data System (ADS)

    Chen, A. T.; Shen, C. C.; Tan, M.; Li, T.; Uemura, R.; Asami, R.

    2015-12-01

    Paleo-temperature recorded in nature archives is a critical parameter to understand climate change in the past. With advantages of unique inert chemical characteristics and sensitive solubilities with temperature, dissolved noble gases in speleothem inclusion water were recently proposed to retrieve terrestrial temperature history. In order to accurately apply this newly-developed speleothem noble gas temperature (NGT) as a reliable proxy, a fundamental issue about behaviors of noble gases in the karst should be first clarified. In this study, we measured noble gas contents in air and dripping water to evaluate any ratio deviation between noble gases. Cave dripping water samples was collected from three selected caves, Shihua Cave in northern China, Furong Cave in southwestern, and Gyukusen Cave in an island located in the western Pacific. For these caves are characterized by a thorough mixing and long-term storage of waters in a karst aquifer by the absence of seasonal oxygen isotope shifts. Ratios of dripping water noble gases are statistically insignificant from air data. Helium isotopic ratios in the dripping water samples match air value. The results indicate that elemental and isotopic signatures of noble gases from air can be frankly preserved in the epikarst and support the fidelity of NGT techniques.

  6. Biomedical Investigations with Laser-Polarized Noble Gas Magnetic Resonance

    NASA Technical Reports Server (NTRS)

    Walsworth, Ronald L.

    2003-01-01

    We pursued advanced technology development of laser-polarized noble gas nuclear magnetic resonance (NMR) as a novel biomedical imaging tool for ground-based and eventually space-based application. This new multidisciplinary technology enables high-resolution gas-space magnetic resonance imaging (MRI)-e.g., of lung ventilation-as well as studies of tissue perfusion. In addition, laser-polarized noble gases (3He and 129Xe) do not require a large magnetic field for sensitive detection, opening the door to practical MRI at very low magnetic fields with an open, lightweight, and low-power device. We pursued two technology development specific aims: (1) development of low-field (less than 0.01 T) noble gas MRI of humans; and (2) development of functional MRI of the lung using laser-polarized noble gas and related techniques.

  7. Noble-gas-rich separates from ordinary chondrites

    NASA Astrophysics Data System (ADS)

    Moniot, R. K.

    1980-02-01

    Acid-resistant residues were prepared by HCl-HF demineralization of three H-type ordinary chondrites: Brownfield 1937 (H3), Dimmitt (H3, 4), and Estacado (H6). These residues were found to contain a large proportion of the planetary-type trapped Ar, Kr, and Xe in the meteorites. The similarity of these acid residues to those from carbonaceous chondrites and LL-type ordinary chondrites suggests that the same phase carries the trapped noble gases in all these diverse meteorite types. Because the H group represents a large fraction of all meteorites, this result indicates that the gas-rich carrier phase is as universal as the trapped noble-gas component itself. When treated with an oxidizing etchant, the acid residues lost almost all their complement of noble gases.

  8. Determining noble gas partitioning within a CO2-H2O system at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Warr, Oliver; Rochelle, Christopher A.; Masters, Andrew; Ballentine, Christopher J.

    2015-06-01

    Quantifying the distribution of noble gases between phases is essential for using these inert trace gases to track the processes controlling multi-phase subsurface systems. Here we present experimental data that defines noble gas partitioning for two phase CO2-water systems. These are at the pressure and temperature range relevant for engineered systems used for anthropogenic carbon capture and geological storage (CCS) technologies, and CO2-rich natural gas reservoirs (CO2 density range 169-656 kg/m3 at 323-377 K and 89-134 bar). The new partitioning data are compared to predictions of noble gas partitioning determined in low-pressure, pure noble gas-water systems for all noble gases except neon and radon. At low CO2 density there was no difference between measured noble gas partitioning and that predicted in pure noble gas-water systems. At high CO2 density, however, partition coefficients express significant deviation from pure noble gas-water systems. At 656 kg/m3, these deviations are -35%, 74%, 113% and 319% for helium, argon, krypton and xenon, respectively. A second order polynomial fit to the data for each noble gas describes the deviation from the pure noble gas-water system as a function of CO2 density. We argue that the difference between pure noble gas-water systems and the high density CO2-water system is due to an enhanced degree of molecular interactions occurring within the dense CO2 phase due to the combined effect of inductive and dispersive forces acting on the noble gases. As the magnitude of these forces are related to the size and polarisability of each noble gas, xenon followed by krypton and argon become significantly more soluble within dense CO2. In the case of helium repulsive forces dominate and so it becomes less soluble as a function of CO2 density.

  9. Determination of natural in vivo noble-gas concentrations in human blood.

    PubMed

    Tomonaga, Yama; Brennwald, Matthias S; Livingstone, David M; Tomonaga, Geneviève; Kipfer, Rolf

    2014-01-01

    Although the naturally occurring atmospheric noble gases He, Ne, Ar, Kr, and Xe possess great potential as tracers for studying gas exchange in living beings, no direct analytical technique exists for simultaneously determining the absolute concentrations of these noble gases in body fluids in vivo. In this study, using human blood as an example, the absolute concentrations of all stable atmospheric noble gases were measured simultaneously by combining and adapting two analytical methods recently developed for geochemical research purposes. The partition coefficients determined between blood and air, and between blood plasma and red blood cells, agree with values from the literature. While the noble-gas concentrations in the plasma agree rather well with the expected solubility equilibrium concentrations for air-saturated water, the red blood cells are characterized by a distinct supersaturation pattern, in which the gas excess increases in proportion to the atomic mass of the noble-gas species, indicating adsorption on to the red blood cells. This study shows that the absolute concentrations of noble gases in body fluids can be easily measured using geochemical techniques that rely only on standard materials and equipment, and for which the underlying concepts are already well established in the field of noble-gas geochemistry.

  10. Consent Decree for Noble Energy

    EPA Pesticide Factsheets

    Noble Energy, Inc. (Noble) that comprehensively identifies and addresses issues with vapor control systems at Noble’s condensate storage tank batteries in the Denver-area 8-hour ozone marginal nonattainment area (nonattainment area).

  11. Solubility investigations in support of ultrasensitive noble gas detector development.

    SciTech Connect

    Gross, K. C.

    1998-08-05

    Argonne National Laboratory (ANL) and the University of Cincinnati (UC) have been developing a new class of ultrasensitive noble gas detectors that are based upon the ANL discovery that corn oil has a high affinity for heavy noble gas absorption at room temperature, but releases the noble gases with warming or by other low-energy-input means. Environmental applications for this new class of fluid-based detectors include ultrahigh sensitivity radioxenon detectors for Comprehensive Test Ban Treaty Surveillance, improved fission gas detectors for enhanced environmental surveillance in the vicinity of DOE, DOD, and NRC-licensed facilities, and improved integrating Rn detectors for earthquake prediction. The purpose of the present paper is to present the results of theoretical and experimental investigations into the solubility phenomena of heavy noble gases (Rn, Xe, and Kr) in triglyceride oils. It is the authors' intention that the findings presented herein may be used to guide future selection, development, and refinement of vegetable and other hydrocarbon oils to bring further enhancements to noble gas detection efficiencies.

  12. Defining Noble Gas Partitioning for Carbon Capture and Storage Environments

    NASA Astrophysics Data System (ADS)

    Warr, O.; Masters, A.; Rochelle, C.; Ballentine, C. J.

    2014-12-01

    For viable CCS implementation variables such as CO2 dissolution rates, reactions with the host rock and the extent of groundwater interaction must be accurately constrained. Noble gases play an important role in these systems [e.g. 1,2]. Their application, however, requires accurate Henry's constants within dense CO2-H2O systems. Current interpretations use pure noble gas-H2O partitioning data [3,4] and assume CO2-noble gas interactions are negligible, even at high (>700 kg/m3) CO2 densities [2]. To test this assumption we experimentally determined noble gas CO2-H2O partitioning for the 170-656 kg/m3 CO2 density range; representative of most CCS environments. Contrary to assumption, CO2 density significantly affected noble gas partition coefficients. For helium, increasing CO2 density resulted in a negative deviation trend from CO2-free values whilst for argon, krypton and xenon strong, positive deviations were observed. At 656 kg/m3 these deviations were -35%, 74%, 114% and 321% respectively. This is interpreted as the CO2 phase acting as a polar solvent inducing polarisation in the noble gases. Deviation trends are well defined using a 2nd order polynomial. The effect of a dense CO2 phase can now be incorporated into existing noble gas models. We also present results from a Gibbs-Ensemble Monte Carlo molecular simulation to model partitioning for this binary system. This fundamental technique makes predictions based on the pair-potentials of interaction between the molecules. Here it gives the phase compositions and Henry coefficients for noble gases. With a proven ability in accurately replicating both the CO2-H2O system and low pressure noble gas Henry constants the focus is now on fully optimising the model to match high pressure observations. [1] Gilfillan et al. (2009) Nature 458 614-618 [2] Gilfillan et al. (2008) GCA 72 1174-1198 [3] Crovetto et al. (1982) J.Chem.Phys. 76 1077-1086 [4] Ballentine et al. in Porcelli et al. (eds.) (2002) Rev.Min.Geo. 47 539-614.

  13. Pressure broadening and frequency shift of the 5S1/2 → 5D5/2 and 5S1/2 → 7S1/2 two photon transitions in 85Rb by the noble gases and N2

    NASA Astrophysics Data System (ADS)

    Zameroski, Nathan D.; Hager, Gordon D.; Erickson, Christopher J.; Burke, John H.

    2014-11-01

    Doppler free two photon absorption spectroscopy was employed to measure the pressure broadening and frequency shift rates of the 5S1/2 (F = 3) → 5D5/2 (F = 5, 4, 3, 2, 1) (778.105 nm) and the 5S1/2 (F = 2) → 7S1/2 (F = 2) (760.126 nm) two photon transitions in 85Rb by the noble gases and N2. To our knowledge, these rates are reported on for the first time. The self-broadening and shift rate of the 5S1/2 (F = 3) → 5D5/2 (F = 5, 4, 3, 2, 1) transition and self -broadening rate of the 5S1/2 (F = 2) → 7S1/2 (F = 2) transition were also measured. The temperature dependence of the self-frequency shift (Rb-Rb collisions) of these transitions is presented. Helium diffusion rates through Quartz and Pyrex cells are also calculated and the implication of helium diffusion through glass vapor cells is discussed in regards to atomic frequency standards based on these transitions. Experimental pressure broadening and shift rates are compared to theoretically calculated rates assuming a 6, 8 or 6, 8, 10 difference potential and pseudo potential model. Reasonable agreement is achieved between experimental and theoretical values.

  14. Element distribution and noble gas isotopic abundances in lunar meteorite Allan Hills A81005

    NASA Technical Reports Server (NTRS)

    Kraehenbuehl, U.; Eugster, O.; Niedermann, S.

    1986-01-01

    Antarctic meteorite ALLAN HILLS A81005, an anorthositic breccia, is recognized to be of lunar origin. The noble gases in this meteorite were analyzed and found to be solar-wind implanted gases, whose absolute and relative concentrations are quite similar to those in lunar regolith samples. A sample of this meteorite was obtained for the analysis of the noble gas isotopes, including Kr(81), and for the determination of the elemental abundances. In order to better determine the volume derived from the surface correlated gases, grain size fractions were prepared. The results of the instrumental measurements of the gamma radiation are listed. From the amounts of cosmic ray produced noble gases and respective production rates, the lunar surface residence times were calculated. It was concluded that the lunar surface time is about half a billion years.

  15. Noble gas isotopic composition as a key reference parameter in a planetary atmospheric evolution model

    NASA Astrophysics Data System (ADS)

    Ozima, M.

    2010-12-01

    The isotopic composition of noble gases is a key reference parameter in discussing the evolution of planetary atmospheres. Currently, two widely occurring noble gas components are identified in the early solar system, one is the Solar Wind noble gas (SW-noble gas, hereafter) and another is the Q-noble gas in unaltered meteorites: both noble gases are characterized by their ubiquitous occurrence and high isotopic homogeneity. Since the SW-noble gas is directly ejected from the Sun, it has been assumed to be a good proxy of the average noble gas isotopic composition in the Sun, namely the solar noble gas. The systematic enrichment of the heavier isotopes in the Q-noble gas relative to the SW-noble gas is then commonly attributed to its isotopic fractionation from the SW-noble gas. However, the isotopic compositions of the SW-noble gas either implanted on lunar soils or trapped by artificial targets show considerable isotopic variation depending on the velocity of the Solar Wind. Therefore, it is important to examine how closely the SW-noble gas represents the indigenous solar noble gas component or the mean isotopic composition of noble gases of the Sun. Here we show that the isotopic composition of the SW-noble gas is substantially fractionated relative to the solar value, and therefore should not be used as a reference parameter. We further suggest that the post D-burning Q-noble gas (see below) is the better proxy of the solar noble gas, and this should be used as a reference of the Solar noble gas isotopic composition in discussing the planetary atmospheric evolution. The most distinct difference between the Q- and the SW-noble gas is apparent in a 3He/4He isotopic ratio: 4.64e-4 in Q-He [1], but 1.23e-4 in SW-He[2]. The difference is attributed to the conversion of deuteron (D) to 3He in the Sun, namely the D-burning [3], due to high temperature during the pre-main sequence stage of the Sun. With the use of recent data on D/H ratios from helio-seismology [4] and

  16. Noble gas loss may indicate groundwater flow across flow barriers in southern Nevada

    USGS Publications Warehouse

    Thomas, J.M.; Bryant, Hudson G.; Stute, M.; Clark, J.F.

    2003-01-01

    Average calculated noble gas temperatures increase from 10 to 22oC in groundwater from recharge to discharge areas in carbonate-rock aquifers of southern Nevada. Loss of noble gases from groundwater in these regional flow systems at flow barriers is the likely process that produces an increase in recharge noble gas temperatures. Emplacement of low permeability rock into high permeability aquifer rock and the presence of low permeability shear zones reduce aquifer thickness from thousands to tens of meters. At these flow barriers, which are more than 1,000 m lower than the average recharge altitude, noble gases exsolve from the groundwater by inclusion in gas bubbles formed near the barriers because of greatly reduced hydrostatic pressure. However, re-equilibration of noble gases in the groundwater with atmospheric air at the low altitude spring discharge area, at the terminus of the regional flow system, cannot be ruled out. Molecular diffusion is not an important process for removing noble gases from groundwater in the carbonate-rock aquifers because concentration gradients are small.

  17. Biomedical Investigations with Laser-Polarized Noble Gas Magnetic Resonance

    NASA Technical Reports Server (NTRS)

    Walsworth, Ronald L.

    2001-01-01

    We are developing laser-polarized noble gas nuclear magnetic resonance (NMR) as a novel biomedical imaging tool for ground-based and eventually space-based application. This emerging multidisciplinary technology enables high-resolution gas-space magnetic resonance imaging (MRI) (e.g., of lung ventilation) as well as studies of tissue perfusion. In addition, laser-polarized noble gases (He-3 and Xe-129) do not require a large magnetic field for sensitive detection, opening the door to practical MRI at very low magnetic fields with an open, lightweight, and low-power device. We are pursuing two specific aims in this research. The first aim is to develop a low-field (< 0.01 T) instrument for noble gas MRI of humans, and the second aim is to develop functional MRI of the lung using laser-polarized Xe-129 and related techniques.

  18. Experimental studies and model analysis of noble gas fractionation in porous media

    USGS Publications Warehouse

    Ding, Xin; Kennedy, B. Mack.; Evans, William C.; Stonestrom, David A.

    2016-01-01

    The noble gases, which are chemically inert under normal terrestrial conditions but vary systematically across a wide range of atomic mass and diffusivity, offer a multicomponent approach to investigating gas dynamics in unsaturated soil horizons, including transfer of gas between saturated zones, unsaturated zones, and the atmosphere. To evaluate the degree to which fractionation of noble gases in the presence of an advective–diffusive flux agrees with existing theory, a simple laboratory sand column experiment was conducted. Pure CO2 was injected at the base of the column, providing a series of constant CO2 fluxes through the column. At five fixed sampling depths within the system, samples were collected for CO2 and noble gas analyses, and ambient pressures were measured. Both the advection–diffusion and dusty gas models were used to simulate the behavior of CO2 and noble gases under the experimental conditions, and the simulations were compared with the measured depth-dependent concentration profiles of the gases. Given the relatively high permeability of the sand column (5 ´ 10−11 m2), Knudsen diffusion terms were small, and both the dusty gas model and the advection–diffusion model accurately predicted the concentration profiles of the CO2 and atmospheric noble gases across a range of CO2 flux from ?700 to 10,000 g m−2 d−1. The agreement between predicted and measured gas concentrations demonstrated that, when applied to natural systems, the multi-component capability provided by the noble gases can be exploited to constrain component and total gas fluxes of non-conserved (CO2) and conserved (noble gas) species or attributes of the soil column relevant to gas transport, such as porosity, tortuosity, and gas saturation.

  19. Noble Gas Signatures in Greenland - Tracing Glacial Meltwater Sources

    NASA Astrophysics Data System (ADS)

    Niu, Y.; Castro, M. C.; Hall, C. M.; Aciego, S.; Stevenson, E. I.; Arendt, C. A.

    2014-12-01

    This study is meant to explore the information noble gases can provide in glacial environments with respect to glacial meltwater sources, relative source contributions, water residence times, and spatial location where this glacial meltwater originates in the ice sheet. Ultimately, we seek to improve our understanding on the dynamics of these massive ice sheets, critical for the major role they play on climate change. This is possible due to the conservative nature of noble gases and temperature dependency of their concentrations in water in equilibrium with the atmosphere (ASW) allowing for calculation of noble gas temperatures (NGTs) and, under certain assumptions, estimation of the altitude at which glacial meltwater originated. In addition, crustally produced isotopes such as He accumulate in water over time, allowing for estimation of water residence times. Glacial meltwater samples were collected and analyzed for noble gas concentrations and isotopic ratios at five different locations in southern Greenland, between sea level and 1221 m. All samples are enriched in He with respect to ASW and are depleted in all other noble gases. Two patterns are apparent. The first one presents a relative Ar enrichment with respect to Ne, Kr, and Xe, a pattern first observed in high-altitude springs in the Galápagos Islands. The second one displays a mass-dependent pattern, a pattern first observed in Michigan rainwater samples. Most samples point to equilibration temperatures at ~0°C and altitudes between 1000 m and 2000 m, values which are consistent with both temperatures and elevations in Greenland. He concentrations vary between 1.1 and 7 times that of ASW and suggest glacial meltwater ages between ~170 and 1150 yrs, a result which is consistent with a preliminary tritium analysis. He isotopes point to surface (precipitation as snow and rainfall) contributions for most samples between ~60% and 90% with a ~10% - 40% crustal contribution from groundwater.

  20. Appraisal of transport and deformation in shale reservoirs using natural noble gas tracers

    SciTech Connect

    Heath, Jason E.; Kuhlman, Kristopher L.; Robinson, David G.; Bauer, Stephen J.; Gardner, William Payton

    2015-09-01

    This report presents efforts to develop the use of in situ naturally-occurring noble gas tracers to evaluate transport mechanisms and deformation in shale hydrocarbon reservoirs. Noble gases are promising as shale reservoir diagnostic tools due to their sensitivity of transport to: shale pore structure; phase partitioning between groundwater, liquid, and gaseous hydrocarbons; and deformation from hydraulic fracturing. Approximately 1.5-year time-series of wellhead fluid samples were collected from two hydraulically-fractured wells. The noble gas compositions and isotopes suggest a strong signature of atmospheric contribution to the noble gases that mix with deep, old reservoir fluids. Complex mixing and transport of fracturing fluid and reservoir fluids occurs during production. Real-time laboratory measurements were performed on triaxially-deforming shale samples to link deformation behavior, transport, and gas tracer signatures. Finally, we present improved methods for production forecasts that borrow statistical strength from production data of nearby wells to reduce uncertainty in the forecasts.

  1. Perspectives of hyperpolarized noble gas MRI beyond 3He

    NASA Astrophysics Data System (ADS)

    Lilburn, David M. L.; Pavlovskaya, Galina E.; Meersmann, Thomas

    2013-04-01

    Nuclear Magnetic Resonance (NMR) studies with hyperpolarized (hp) noble gases are at an exciting interface between physics, chemistry, materials science and biomedical sciences. This paper intends to provide a brief overview and outlook of magnetic resonance imaging (MRI) with hp noble gases other than hp 3He. A particular focus are the many intriguing experiments with 129Xe, some of which have already matured to useful MRI protocols, while others display high potential for future MRI applications. Quite naturally for MRI applications the major usage so far has been for biomedical research but perspectives for engineering and materials science studies are also provided. In addition, the prospects for surface sensitive contrast with hp 83Kr MRI is discussed.

  2. Light noble gas dissolution into ring structure-bearing materials and lattice influences on noble gas recycling

    NASA Astrophysics Data System (ADS)

    Jackson, Colin R. M.; Parman, Stephen W.; Kelley, Simon P.; Cooper, Reid F.

    2015-06-01

    Light noble gas (He-Ne-Ar) solubility has been experimentally determined in a range of materials with six-member, tetrahedral ring structures: beryl, cordierite, tourmaline, antigorite, muscovite, F-phlogopite, actinolite, and pargasite. Helium solubility in these materials is relatively high, 4 × 10-10 to 3 × 10-7 mol g-1 bar-1, which is ∼100 to 100,000× greater than He solubility in olivine, pyroxene, or spinel. Helium solubility broadly correlates with the topology of ring structures within different minerals. Distinctive He-Ne-Ar solubility patterns are associated with the different ring structure topologies. Combined, these observations suggest ring structures have a strong influence on noble gas solubility in materials and could facilitate the recycling of noble gases, along with other volatiles (i.e., water, chlorine, and fluorine), into the mantle. Measurements of Ne and Ar solubility in antigorite, however, are highly variable and correlated with each other, suggesting multiple factors contribute the solubility of noble gases in serpentine-rich materials.

  3. Pressure broadening and shift of the cesium D{sub 1} transition by the noble gases and N{sub 2}, H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and {sup 3}He

    SciTech Connect

    Pitz, Greg A.; Wertepny, Douglas E.; Perram, Glen P.

    2009-12-15

    The pressure broadening and shift rates for the cesium D{sub 1} (6 {sup 2}P{sub 1/2}<-6 {sup 2}S{sub 1/2}) transition with the noble gases and N{sub 2}, H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and {sup 3}He were obtained for pressures less than 300 torr at temperatures under 65 deg. C by means of laser absorption spectroscopy. The collisional broadening rate, gamma{sub L}, for He, Ne, Ar, Kr, Xe, N{sub 2}, H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and {sup 3}He are 24.13, 10.85, 18.31, 17.82, 19.74, 16.64, 20.81, 20.06, 18.04, 29.00, 26.70, 18.84, and 26.00 MHz/torr, respectively. The corresponding pressure-induced shift rates, delta, are 4.24, -1.60, -6.47, -5.46, -6.43, -7.76, 1.11, 0.47, 0.00, -9.28, -8.54, -6.06, and 6.01 MHz/torr. These rates have then been utilized to calculate Lennard-Jones potential coefficients to quantify the interatomic potential surfaces. The broadening cross section has also been shown to correlate with the polarizability of the collision partner.

  4. Photoionization of noble-gas atoms by ultrashort electromagnetic pulses

    SciTech Connect

    Astapenko, V. A. Svita, S. Yu.

    2014-11-15

    The photoionization of atoms of noble gases (Ar, Kr, and Xe) by ultrashort electromagnetic pulses of a corrected Gaussian shape is studied theoretically. Computations are performed in the context of perturbation theory using a simple expression for the total probability of photoionization of an atom by electromagnetic pulses. The features of this process are revealed and analyzed for various ranges of the parameters of the problem.

  5. High temperature, oxidation resistant noble metal-Al alloy thermocouple

    NASA Technical Reports Server (NTRS)

    Smialek, James L. (Inventor); Gedwill, Michael G. (Inventor)

    1994-01-01

    A thermocouple is disclosed. The thermocouple is comprised of an electropositive leg formed of a noble metal-Al alloy and an electronegative leg electrically joined to form a thermocouple junction. The thermocouple provides for accurate and reproducible measurement of high temperatures (600 - 1300 C) in inert, oxidizing or reducing environments, gases, or vacuum. Furthermore, the thermocouple circumvents the need for expensive, strategic precious metals such as rhodium as a constituent component. Selective oxidation of rhodium is also thereby precluded.

  6. The MSFC Noble Gas Research Laboratory (MNGRL): A NASA Investigator Facility

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara

    2016-01-01

    Noble-gas isotopes are a well-established technique for providing detailed temperature-time histories of rocks and meteorites. We have established the MSFC Noble Gas Research Laboratory (MNGRL) at Marshall Space Flight Center to serve as a NASA investigator facility in the wake of the closure of the JSC laboratory formerly run by Don Bogard. The MNGRL lab was constructed to be able to measure all the noble gases, particularly Ar-Ar and I-Xe radioactive dating to find the formation age of rocks and meteorites, and Ar/Kr/Ne cosmic-ray exposure ages to understand when the meteorites were launched from their parent planets.

  7. Performance of the High Resolution, Multi-collector Helix MC Plus Noble Gas Mass Spectrometer at the Australian National University

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaodong; Honda, Masahiko; Hamilton, Doug

    2016-12-01

    Performance of the Helix MC Plus noble gas mass spectrometer installed at the Australian National University (ANU) is reported. Results for sensitivity, mass discrimination and their linearity against partial pressure of noble gases, and mass resolution of the mass spectrometer are presented, and the results are compared with those of conventional noble gas mass spectrometers. The application of the five detectors on the Helix MC Plus in measuring various noble gas isotopes in multi-collector modes and the integration of the software drivers of peripheral hardware devices into the controlling program Qtegra of the mass spectrometer are discussed. High mass resolution (>1800) and mass resolving power (>8000) make this mass spectrometer unique in noble gas cosmo-geochemistry. It provides the capability to measure isobaric interference-free noble gas isotopes in multi-collector mode, significantly improves the accuracy to determine isotopic ratios, and greatly increases the efficiency of data acquisition.

  8. Calibration of Dissolved Noble Gas Mass Spectrometric Measurements by an Air-Water Equilibration System

    NASA Astrophysics Data System (ADS)

    Hillegonds, Darren; Matsumoto, Takuya; Jaklitsch, Manfred; Han, Liang-Feng; Klaus, Philipp; Wassenaar, Leonard; Aggarwal, Pradeep

    2013-04-01

    Precise measurements by mass spectrometry of dissolved noble gases (He, Ar, Ne, Kr, Xe) in water samples require careful calibration against laboratory standards with known concentrations. Currently, air pipettes are used for day-to-day calibrations, making estimation of overall analytical uncertainties for dissolved noble gas measurements in water difficult. Air equilibrated water (AEW) is often used as a matrix-equivalent laboratory standard for dissolved gases in groundwater, because of the well-known and constant fractions of noble gases in the atmosphere. AEW standards, however, are only useful if the temperature and pressure of the gas-water equilibrium can be controlled and measured precisely (i.e., to better than 0.5%); contamination and partial sample degassing must also be prevented during sampling. Here we present the details of a new custom air-water equilibration system which consists of an insulated 600 liter tank filled with deionized water, held isothermally at a precise target temperature (<0.05 °C) through the use of a heat exchanger. The temperature and total dissolved gas of the water in the tank are monitored continually, as are atmospheric pressure and air temperature in the laboratory. Different noble gas concentration standards can be reliably produced by accurately controlling the water temperature of the equilibration system. Equilibration characteristics and reproducibility of this system for production of copper tubes containing known amounts of noble gases will be presented.

  9. 77 FR 70159 - Marble River, LLC v. Noble Clinton Windpark I, LLC, Noble Ellenburg Windpark, LLC, Noble...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-23

    ... Energy Regulatory Commission Marble River, LLC v. Noble Clinton Windpark I, LLC, Noble Ellenburg Windpark..., Marble River, LLC (Marble River or Complainant) filed a formal complaint against Noble Clinton Windpark I... pay Marble River for headroom created by common system upgrade facilities that benefit Noble and...

  10. Noble metals in oncology

    PubMed Central

    Markowska, Anna; Jaszczyńska-Nowinka, Karolina; Lubin, Jolanta; Markowska, Janina

    2015-01-01

    Worldwide research groups are searching for anticancer compounds, many of them are organometalic complexes having platinum group metals as their active centers. Most commonly used cytostatics from this group are cisplatin, carboplatin and oxaliplatin. Cisplatin was used fot the first time in 1978, from this time many platinum derivatives were created. In this review we present biological properties and probable future clinical use of platinum, gold, silver, iridium and ruthenium derivatives. Gold derivative Auranofin has been studied extensively. Action of silver nanoparticles on different cell lines was analysed. Iridium isotopes are commonly used in brachyterapy. Ruthenium compound new anti-tumour metastasis inhibitor (NAMI-A) is used in managing lung cancer metastases. Electroporation of another ruthenium based compound KP1339 was also studied. Most of described complexes have antiproliferative and proapoptotic properties. Further studies need to be made. Nevertheless noble metal based chemotherapheutics and compounds seem to be an interesting direction of research. PMID:26557773

  11. Assessment of Noble Gases in the Savannah River Site Environment

    SciTech Connect

    Carlton, W.H.; Murphy, C.E. Jr.

    1995-04-01

    A series of documents has been published that assesses the impact of various radionuclides released to the environment by Savannah River Site operations. The quantity released, the disposition of the radionuclides in the environment, and the dose to offsite individuals has been presented for carbon, cesium, iodine, plutonium, strontium, technetium, tritium, and uranium. An assessment of the impact of non-radioactive mercury also has been published.

  12. Noble gases in diamonds - Occurrences of solarlike helium and neon

    NASA Technical Reports Server (NTRS)

    Honda, M.; Reynolds, J. H.; Roedder, E.; Epstein, S.

    1987-01-01

    Seventeen diamond samples from diverse locations were analyzed for the contents of He, Ar, Kr, and Xe, and of their isotopes, using a Reynolds (1956) type glass mass spectrometer. The results disclosed a large spread in the He-3/He-4 ratios, ranging from values below atmospheric to close to the solar ratio. In particular, solarlike He-3/He-4 ratios were seen for an Australian colorless diamond composite and an Arkansas diamond, which also displayed solarlike neon isotopic ratios. Wide variation was also observed in the He-4/Ar-40 ratios, suggesting a complex history for the source regions and the diamond crystallization processes.

  13. Method for the purification of noble gases, nitrogen and hydrogen

    DOEpatents

    Baker, J.D.; Meikrantz, D.H.; Tuggle, D.G.

    1997-09-23

    A method and apparatus are disclosed for the purification and collection of hydrogen isotopes in a flowing inert gaseous mixture containing impurities, wherein metal alloy getters having the capability of sorbing non-hydrogen impurities such as oxygen, carbon dioxide, carbon monoxide, methane, ammonia, nitrogen and water vapor are utilized to purify the gaseous mixture of impurities. After purification hydrogen isotopes may be more efficiently collected. A plurality of parallel process lines utilizing metal getter alloys can be used to provide for the continuous purification and collection of the hydrogen isotopes. 15 figs.

  14. Method for the purification of noble gases, nitrogen and hydrogen

    DOEpatents

    Baker, John D.; Meikrantz, David H.; Tuggle, Dale G.

    1997-01-01

    A method and apparatus for the purification and collection of hydrogen isotopes in a flowing inert gaseous mixture containing impurities, wherein metal alloy getters having the capability of sorbing non-hydrogen impurities such as oxygen, carbon dioxide, carbon monoxide, methane, ammonia, nitrogen and water vapor are utilized to purify the gaseous mixture of impurities. After purification hydrogen isotopes may be more efficiently collected. A plurality of parallel process lines utilizing metal getter alloys can be used to provide for the continuous purification and collection of the hydrogen isotopes.

  15. Two- and three-photon ionization in the noble gases

    NASA Astrophysics Data System (ADS)

    McGuire, E. J.

    1981-08-01

    By using a characteristic Green's function for an exactly solvable Schrödinger equation with an approximation to the central potential of Hermann and Skillman, the cross section for nonresonant two- and three-photon ionization of Ne, Ar, Kr, and Xe were calculated in jl coupling. Expressions for cross sections in jl coupling are given. Comparison with the Ar two-photon cross section of Pindzola and Kelly, calculated using the many-body theory, the dipole-length approximation, and LS coupling shows a disagreement of as much as a factor of 2. The disagreement appears to arise from distortion introduced by shifting the Green's-function resonances to experimental values.

  16. The Chemistry of the Noble Gases, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Chernick, Cedric L.

    The history of the discovery, isolation, characterization, production and use of argon, krypton, xenon, helium, and radon is followed by an account of early attempts to react them with other elements. The use of the electron shell theory of valence to explain their inertness and the reactions of chemists to the production of xenon compounds is…

  17. Effect of noble gases on an atmospheric greenhouse /Titan/.

    NASA Technical Reports Server (NTRS)

    Cess, R.; Owen, T.

    1973-01-01

    Several models for the atmosphere of Titan have been investigated, taking into account various combinations of neon and argon. The investigation shows that the addition of large amounts of Ne and/or Ar will substantially reduce the hydrogen abundance required for a given greenhouse effect. The fact that a large amount of neon should be present if the atmosphere is a relic of the solar nebula is an especially attractive feature of the models, because it is hard to justify appropriate abundances of other enhancing agents.

  18. Research of medical gases in Poland

    PubMed Central

    2013-01-01

    Research of medical gases is well established in Poland and has been marked with the foundation of several professional societies. Numerous academic centers including those dealing with hyperbaric and diving medicine conduct studies of medical gases, in vast majority supported with intramural funds. In general, Polish research of medical gases is very much clinical in nature, covering new applications and safety of medical gases in medicine; on the other hand there are several academic centers pursuing preclinical studies, and elaborating basic theories of gas physiology and mathematical modeling of gas exchange. What dominates is research dealing with oxygen and ozone as well as studies of anesthetic gases and their applications. Finally, several research directions involving noble gas, hydrogen and hydrogen sulfide for cell protection, only begin to gain recognition of basic scientists and clinicians. However, further developments require more monetary spending on research and clinical testing as well as formation of new collective bodies for coordinating efforts in this matter. PMID:23916016

  19. Signal-to-noise ratio comparison of encoding methods for hyperpolarized noble gas MRI

    NASA Technical Reports Server (NTRS)

    Zhao, L.; Venkatesh, A. K.; Albert, M. S.; Panych, L. P.

    2001-01-01

    Some non-Fourier encoding methods such as wavelet and direct encoding use spatially localized bases. The spatial localization feature of these methods enables optimized encoding for improved spatial and temporal resolution during dynamically adaptive MR imaging. These spatially localized bases, however, have inherently reduced image signal-to-noise ratio compared with Fourier or Hadamad encoding for proton imaging. Hyperpolarized noble gases, on the other hand, have quite different MR properties compared to proton, primarily the nonrenewability of the signal. It could be expected, therefore, that the characteristics of image SNR with respect to encoding method will also be very different from hyperpolarized noble gas MRI compared to proton MRI. In this article, hyperpolarized noble gas image SNRs of different encoding methods are compared theoretically using a matrix description of the encoding process. It is shown that image SNR for hyperpolarized noble gas imaging is maximized for any orthonormal encoding method. Methods are then proposed for designing RF pulses to achieve normalized encoding profiles using Fourier, Hadamard, wavelet, and direct encoding methods for hyperpolarized noble gases. Theoretical results are confirmed with hyperpolarized noble gas MRI experiments. Copyright 2001 Academic Press.

  20. Noble gas encapsulation: clathrate hydrates and their HF doped analogues.

    PubMed

    Mondal, Sukanta; Chattaraj, Pratim Kumar

    2014-09-07

    The significance of clathrate hydrates lies in their ability to encapsulate a vast range of inert gases. Although the natural abundance of a few noble gases (Kr and Xe) is poor their hydrates are generally abundant. It has already been reported that HF doping enhances the stability of hydrogen hydrates and methane hydrates, which prompted us to perform a model study on helium, neon and argon hydrates with their HF doped analogues. For this purpose 5(12), 5(12)6(8) and their HF doped analogues are taken as the model clathrate hydrates, which are among the building blocks of sI, sII and sH types of clathrate hydrate crystals. We use the dispersion corrected and gradient corrected hybrid density functional theory for the calculation of thermodynamic parameters as well as conceptual density functional theory based reactivity descriptors. The method of the ab initio molecular dynamics (AIMD) simulation is used through atom centered density matrix propagation (ADMP) techniques to envisage the structural behaviour of different noble gas hydrates on a 500 fs timescale. Electron density analysis is carried out to understand the nature of Ng-OH2, Ng-FH and Ng-Ng interactions. The current results noticeably demonstrate that the noble gas (He, Ne, and Ar) encapsulation ability of 5(12), 5(12)6(8) and their HF doped analogues is thermodynamically favourable.

  1. Heuristic overlap-exchange model of noble gas chemical shifts

    NASA Astrophysics Data System (ADS)

    Adrian, Frank J.

    2004-05-01

    It is now generally recognized that overlap-exchange interactions are the primary cause of the medium-dependent magnetic shielding (chemical shift) in all noble gases except helium, although the attractive electrostatic-dispersion (van der Waals) interactions play an indirect role in determining the penetration of the interacting species into the repulsive overlap-exchange region. The short-range nature of these overlap-exchange interactions, combined with the fact that they often can be approximated by simple functions of the overlap of the wave functions of the interacting species, suggests a useful semiempirical model of these chemical shifts. In it the total shielding is the sum of shieldings due to pairwise interactions of the noble gas atom with the individual atoms of the medium, with the "atomic" shielding terms either estimated by simple functions of the atomic overlap integrals averaged over their Boltzmann-weighted separations, or determined by fits to experimental data in systems whose complexity makes the former procedure impractical. Results for 129Xe chemical shifts in the noble gases and in a variety of molecular and condensed systems, including families of n-alkanes, straight-chain alcohols, and the endohedral compounds Xe@C60 and Xe@C70 are encouraging for the applicability of the model to systems of technical and biomedical interest.

  2. Helium Solubility in Cyclosilicates and Implications for Noble Gas Recycling

    NASA Astrophysics Data System (ADS)

    Jackson, C.; Kelley, S. P.; Cooper, R. F.; Parman, S. W.

    2011-12-01

    It is commonly assumed that noble gases strictly flux from the mantle to the atmosphere, with negligible recycling, because noble gases are thought to be extremely insoluble in all minerals. To test this hypothesis, we have experimentally determined the He solubility in a suite of cyclosilicate minerals: beryl, tourmaline and cordierite. The experiments were run in a gas pressure vessel. Run products were analyzed by UV laser ablation, noble gas mass spectrometry. He has a remarkably high solubility (>1000 ppm/1.8 kbar PHe) in cyclosilicates with nominally vacant six-member Si-Al-tetrahedra rings. Cyclosilicates with nominally occupied ring sites have substantially lower solubility. This suggests that He dissolution is facilitated by unfilled six-member rings. If true, He should have a high solubility in other minerals that include ring sites, such as phyllosilicates and amphiboles. Subduction zones commonly recycle these minerals, providing a possible mechanism for recycling of noble gases back into the mantle. Gem quality, natural, polished crystals of each mineral were placed into graphite capsules. Pure He gas was used as the pressure medium (1800 bar), allowing for precise control of PHe. Temperatures were held at 750 C and the experimental durations were 8 hours. A capsule of hydrated MgO powder was loaded in the TZM to maintain a non-zero fugacity of water during the experiment. Close visual inspection of the run products gave no indication of breakdown products. Depth profiles (10s of microns) of the mineral faces were completed using a 193 nm excimer laser. Multiple measurements were made on each phase. He concentrations were homogenous, both vertically and horizontally, indicating a close approach to equilibrium and absence of inclusions. Compared to tourmaline, we observe that He is >1000 and >100 times more soluble in cordierite and beryl, respectively. The ring sites, also known as A sites, in beryl and cordierite are nominally vacant, where as the

  3. Experimental determination of noble gas, SF6 and CO2 flow profiles through a porous sandstone

    NASA Astrophysics Data System (ADS)

    Kilgallon, Rachel; Gilfillan, Stuart; Edlmann, Katriona; McDermott, Chris

    2016-04-01

    The noble gases (He, Ne, Ar, Kr and Xe) and SF6 have recently been used as artificial and inherent tracers of CO2 flow and migration from within[1,2] and from geological reservoirs[3]. However, outstanding questions remain, particularly regarding the flow behaviour of the noble gases compared to CO2. Here we present results from specially constructed experimental equipment, which has been used to determine the factors affecting transport of noble gases relative to CO2 in a porous sandstone. The experimental setup consists of a sample loop that can be loaded with a desired gas mixture. This sample can be released as a pulse into a feeder gas stream through a flow cell. The flow cell consists of a 3.6 cm diameter core, which can be of any length. The sample is surrounded by aluminium foil and treated with epoxy resin inside stainless steel tubing. The flow cell is encased by two purpose designed dispersion end plates. Real-time analysis of the arrival peaks of the gases downstream is recorded using a Quadrupole Mass Spectrometer (QMS). For the experiments, a 0.96 m core of Fell Sandstone was selected to represent a porous media. Noble gases and SF6 pulses were flowed through a CO2 carrier gas at five different pressure gradients (10 - 50 kPa) with arrival profiles measured using the QMS. Surprisingly, peak arrival times of He were slower than the other noble gases at each pressure gradient. The differences in peak arrival times between He and other noble gases increased as pressure decreased and the curve profiles for each noble gas differ significantly. The heavier noble gases (Kr and Xe) along with SF6 show a steeper peak rise at initial appearance, but have a longer duration profile than the He curves. Interestingly, the breakthrough curve profiles for both Kr and Xe were similar to SF6 indicating that Kr and Xe could be substituted for SF6, which is a potent greenhouse gas, in tracing applications. In addition, CO2 pulses were passed through a N2 carrier gas. The

  4. Dating native gold by noble gas analyses

    NASA Technical Reports Server (NTRS)

    Niedermann, S.; Eugster, O.; Hofmann, B.; Thalmann, CH.; Reimold, W. U.

    1993-01-01

    Our recent work on He, Ne, and Ar in Alpine gold samples has demonstrated that gold is extremely retentive for He and could thus, in principle, be used for U/Th-He-4 dating. For vein-type gold from Brusson, Northern Italy, we derived a U/Th-He-4 age of 36 Ma, in agreement with the K-Ar formation age of associated muscovites and biotites. However, in placer gold from the Napf area, Central Switzerland, we observed large excesses of both He-4 and radiogenic Ar-40 (Ar-40 sub rad, defined as Ar-40-295.5-Ar-.36). The gas release systematics indicate two distinct noble gas components, one of which is released below about 800 C and the other one at the melting point of gold (1064 C). We now present results of He and Xe measurements in a 1 g placer gold sample from the river Kruempelgraben, as well as He and Ar data for Brusson vein-type gold and for gold from the Lily Gold Mine, South Africa. We calculate reasonable U/Th-He-4 as well as U-Xe ages based on those gases which are released at approximately 800 C. Probably the low-temperature components represent in-situ-produced radiogenic He and fission Xe, whereas the gases evolving when gold melts have been trapped during gold formation. Therefore, only the low-temperature components are relevant for dating purposes.

  5. Applicability of Monte-Carlo Simulation to Equipment Design of Radioactive Noble Gas Monitor

    NASA Astrophysics Data System (ADS)

    Sakai, Hirotaka; Hattori, Kanako; Umemura, Norihiro

    In the nuclear facilities, radioactive noble gas is continuously monitored by using the radioactive noble gas monitor with beta-sensitive plastic scintillation radiation detector. The detection efficiency of the monitor is generally calibrated by using a calibration loop and standard radioactive noble gases such as 85Kr. In this study, the applicability of PHITS to the equipment design of the radioactive noble gas monitor was evaluated by comparing the calculated results to the test results obtained by actual calibration loop tests to simplify the radiation monitor design evaluation. It was confirmed that the calculated results were well matched to the test results of the monitor after the modeling. In addition, the key parameters for equipment design, such as thickness of detector window or depth of the sampler, were also specified and evaluated.

  6. Noble gas trapping and fractionation during synthesis of carbonaceous matter. [in meteorites

    NASA Technical Reports Server (NTRS)

    Frick, U.; Mack, R.; Chang, S.

    1979-01-01

    An investigation of noble gas entrapment during synthesis of carbonaceous, macromolecular, and kerogen-like substances is presented. High molecular weight organic matter synthesized in aqueous condensation reactions contained little gas, and the composition was consistent with fractionation due to noble gas solubility in water; however, propane soot produced during a modified Miller-Urey experiment in an aritificial gas mixture contained high concentrations of trapped noble gases that displayed strong elemental fractionation from their reservoirs. It is concluded that theses experiemnts show that processes exist for synthesis of carbonaceous carriers that result in high noble gas concentrations and strong elemental fractionation at temperatures well above those required by absorption to achieve similar effects.

  7. Targets Involved in Cardioprotection by the Non-Anesthetic Noble Gas Helium.

    PubMed

    Weber, Nina C; Smit, Kirsten F; Hollmann, Markus W; Preckel, Benedikt

    2015-01-01

    Research data from the past decade indicate that noble gases like xenon and helium exert profound cardioprotection when applied before, during or after organ ischemia. Of all noble gases, especially helium, has gained interest in the past years because it does not have an anesthetic "side effect" like xenon, allowing application of this specific gas in numerous clinical ischemia/reperfusion situations. Because helium has several unique characteristics and no hemodynamic side effects, helium could be administered in severely ill patients. Investigations in animals as well as in humans have proven that this noble gas is not completely inert and can induce several biological effects. Though the underlying molecular mechanisms of helium-induced cardiac protection are still not yet fully understood, recently different signaling pathways have been elucidated.

  8. NOBLE GAS PRODUCTION FROM MERCURY SPALLATION AT SNS

    SciTech Connect

    DeVore, Joe R; Lu, Wei; Schwahn, Scott O

    2013-01-01

    Calculations for predicting the distribution of the products of spallation reactions between high energy protons and target materials are well developed and are used for design and operational applications in many projects both within DOE and in other arenas. These calculations are based on theory and limited experimental data that verifies rates of production of some spallation products exist. At the Spallation Neutron Source, a helium stream from the mercury target flows through a system to remove radioactivity from this mercury target offgas. The operation of this system offers a window through which the production of noble gases from mercury spallation by protons may be observed. This paper describes studies designed to measure the production rates of twelve noble gas isotopes within the Spallation Neutron Source mercury target.

  9. Relationship between recent cave temperatures and noble gas temperatures derived from fluid inclusions of modern soda straw stalactites

    NASA Astrophysics Data System (ADS)

    Palcsu, Laszlo; Papp, Laszlo; Major, Zoltan; Molnar, Mihaly

    2010-05-01

    Recently, strong effort is devoted to establish a new method to derive palaeotemperatures from noble gas (Ne, Ar, Kr, Xe) concentrations dissolved in fluid inclusions of speleothems [1-2]. It has been already shown that the water content of the speleothems can be determined via the water vapour pressure after the water has been released from the carbonate samples and collected in a cold finger and then heated up to room temperature. Additionally, the noble gas contents can be precisely measured with noble gas mass spectrometers. Based on these noble gas concentration data sets, a so-called noble gas temperature (NGT) can be calculated meaning a temperature at which the noble gases have been dissolved in water. To use these NGT's as a palaeoclimate proxy, one of the main questions is how these noble gas temperatures reflect the prevailing cave temperature in which the carbonate has grown. We studied noble gas significances in recent soda straw stalactites from more than ten Central European caves covering a temperature range of 1 to 14 °C. Kluge et al. (2008) has shown the soda straw stalactites might contain less excess air, hence they are more suitable samples to derive NGT's, because noble gas abundances from large air inclusions can mask the temperature information. The 14C ages of these soda straw dripstones were obtained to be recent or at least Holocene ages. Thus one can assume that the cave temperatures during carbonate formation were as same as at present. We measured the water and noble gas contents of numerous carbonate samples from soda straw stalactites and calculated noble gas temperatures by a precision of 1 °C or better. Comparing these temperatures with cave temperatures we obtained that they agree well within the uncertainty of the noble gas temperature determination. Therefore, we can conclude if diffusion of noble gas isotopes does not play a significant role in the carbonate lattice this new tool helps the palaeoclimate community to gain

  10. Investigating the nature of noble gas-copper bonds by the quantum theory of atoms in molecules.

    PubMed

    Rodrigues, Eduardo F F; de Sá, Eduardo L; Haiduke, Roberto L A

    2010-04-22

    We investigated noble gas-copper bonds in linear complexes represented by the NgCuX general formula in which Ng and X stand for a noble gas (neon, argon, krypton, or xenon) and a halogen (fluorine, chlorine or bromine), respectively, by coupled cluster methods and modified cc-pVQZ basis sets. The quantum theory of atoms in molecules (QTAIM) shows a linear relation between the dissociation energy of noble gas-copper bonds and the amount of electronic charge transferred mainly from the noble gas to copper during complexation. Large changes in the QTAIM quadrupole moments of copper and noble gases resulting from this bonding and a comparison between NgCuX and NgNaCl systems indicate that these noble gas-copper bonds should be better interpreted as predominantly covalent. Finally, QTAIM atomic dipoles of noble gases in NgNaCl systems agree satisfactorily with atomic dipoles given by a simple model for these NgNa van der Waals bonds.

  11. The Noble Gas Fingerprint in a UK Unconventional Gas Reservoir

    NASA Astrophysics Data System (ADS)

    McKavney, Rory; Gilfillan, Stuart; Györe, Domokos; Stuart, Fin

    2016-04-01

    In the last decade, there has been an unprecedented expansion in the development of unconventional hydrocarbon resources. Concerns have arisen about the effect of this new industry on groundwater quality, particularly focussing on hydraulic fracturing, the technique used to increase the permeability of the targeted tight shale formations. Methane contamination of groundwater has been documented in areas of gas production1 but conclusively linking this to fugitive emissions from unconventional hydrocarbon production has been controversial2. A lack of baseline measurements taken before drilling, and the equivocal interpretation of geochemical data hamper the determination of possible contamination. Common techniques for "fingerprinting" gas from discrete sources rely on gas composition and isotopic ratios of elements within hydrocarbons (e.g. δ13CCH4), but the original signatures can be masked by biological and gas transport processes. The noble gases (He, Ne, Ar, Kr, Xe) are inert and controlled only by their physical properties. They exist in trace quantities in natural gases and are sourced from 3 isotopically distinct environments (atmosphere, crust and mantle)3. They are decoupled from the biosphere, and provide a separate toolbox to investigate the numerous sources and migration pathways of natural gases, and have found recent utility in the CCS4 and unconventional gas5 industries. Here we present a brief overview of noble gas data obtained from a new coal bed methane (CBM) field, Central Scotland. We show that the high concentration of helium is an ideal fingerprint for tracing fugitive gas migration to a shallow groundwater. The wells show variation in the noble gas signatures that can be attributed to differences in formation water pumping from the coal seams as the field has been explored for future commercial development. Dewatering the seams alters the gas/water ratio and the degree to which noble gases degas from the formation water. Additionally the

  12. Greenhouse Gases

    MedlinePlus

    ... Found Solar Thermal Power Plants Solar Thermal Collectors Solar Energy and the Environment Secondary Sources Electricity The Science ... the earth’s atmosphere act as greenhouse gases. When sunlight strikes the earth’s surface, some of it radiates ...

  13. Carbon and Noble Gas Isotope Banks in Two-Phase Flow: Changes in Gas Composition During Migration

    NASA Astrophysics Data System (ADS)

    Sathaye, K.; Larson, T.; Hesse, M. A.

    2015-12-01

    In conjunction with the rise of unconventional oil and gas production, there has been a recent rise in interest in noble gas and carbon isotope changes that can occur during the migration of natural gas. Natural gas geochemistry studies use bulk hydrocarbon composition, carbon isotopes, and noble gas isotopes to determine the migration history of gases from source to reservoir, and to trace fugitive gas leaks from reservoirs to shallow groundwater. We present theoretical and experimental work, which helps to explain trends observed in gas composition in various migration scenarios. Noble gases are used as tracers for subsurface fluid flow due to distinct initial compositions in air-saturated water and natural gases. Numerous field studies have observed enrichments and depletions of noble gases after gas-water interaction. A theoretical two-phase gas displacement model shows that differences in noble gas solubility will cause volatile gas components will become enriched at the front of gas plumes, leaving the surrounding residual water stripped of dissolved gases. Changes in hydrocarbon gas composition are controlled by gas solubility in both formation water and residual oil. In addition to model results, we present results from a series of two-phase flow experiments. These results demonstrate the formation of a noble gas isotope banks ahead of a main CO2 gas plume. Additionally, we show that migrating hydrocarbon gas plumes can sweep biogenic methane from groundwater, significantly altering the isotope ratio of the gas itself. Results from multicomponent, two-phase flow experiments qualitatively agree with the theoretical model, and previous field studies. These experimentally verified models for gas composition changes can be used to aid source identification of subsurface gases.

  14. Bartlett's discovery of noble gas fluorides, a milestone in chemical history.

    PubMed

    Christe, Karl O

    2013-05-21

    In 1962, Neil Bartlett published a terse note in Proc. Chem. Soc. eradicating the long held dogma that noble gases are inert and cannot form stable compounds. This historical discovery has revolutionized our views on chemistry and has given rise to thousands of papers on noble gas chemistry. The fact that his proposed reaction product "Xe(+)[PtF6](-)" has eluded experimental detection for more than half a century and actually was a mixture of XeF(+) and Xe2F3(+) salts does not diminish the enormous impact of his discovery. A plausible explanation for the failures to observe "Xe(+)[PtF6](-)" experimentally is presented.

  15. Noble gas studies in vapor-growth diamonds: Comparison with shock-produced diamonds and the origin of diamonds in ureilites

    SciTech Connect

    Matsuda, Junichi; Fukunaga, Kazuya; Ito, Keisuke )

    1991-07-01

    The authors synthesized vapor-trowth diamonds by two kinds of Chemical Vapor Deposition (CVD) using microwave (MWCVD) and hot filament (HFCVD) ionization of gases, and examined elemental abundances and isotopic compositions of the noble gases trapped in the diamonds. It is remarkable that strong differences existed in the noble gas concentrations in the two kinds of CVD diamonds: large amounts of noble gases were trapped in the MWCVD diamonds, but not in the HFCVD diamonds. The heavy noble gases (Ar to Xe) in the MWCVD diamonds were highly fractionated compared with those in the ambient atmosphere, and are in good agreement with the calculated fractionation patterns for plasma at an electron temperature of 7,000-9,000 K. These results strongly suggest that the trapping mechanism of noble gases in CVD diamonds is ion implantation during diamond growth. The degrees of fractionation of heavy noble gases were also in good agreement with those in ureilites. The vapor-growth hypothesis is discussed in comparison with the impact-shock hypothesis as a better model for the origin of diamonds in ureilites. The diamond (and graphite, amorphous carbon, too) may have been deposited on early condensates such as Re, Ir, W, etc. This model explains the chemical features of vein material in ureilites; the refractory siderophile elements are enriched in carbon and noble gases and low in normal siderophiles. The vapor-growth model is also compatible with the oxygen isotopic data of ureilites which suggests that nebular processes are primarily responsible for the composition of ureilites.

  16. Toxic gases.

    PubMed Central

    Matthews, G.

    1989-01-01

    An overview of the widespread use of gases and some volatile solvents in modern society is given. The usual circumstances in which undue exposure may occur are described. The most prominent symptoms and general principles of diagnosis and treatment are given and are followed by more specific information on the commoner, more toxic materials. While acute poisonings constitute the greater part of the paper, some indication of chronic disorders arising from repeated or prolonged exposure is also given. PMID:2687827

  17. Noble Gas Signatures in Athabasca Glacier - Tracing Glacial Meltwater Sources

    NASA Astrophysics Data System (ADS)

    Niu, Y.; Hall, C. M.; Castro, M. C.; Aciego, S.; Arendt, C. A.

    2015-12-01

    We present a noble gas study in glacial meltwater (GMW) from the Athabasca Glacier (AG) in the Columbia Icefield, Canada. It constrains the relative contributions of GMW sources, water residence times, and spatial locations where the GMW originates in the alpine glacier. This is possible due to the conservative nature of noble gases and temperature dependency of their concentrations in water in equilibrium with the atmosphere (ASW) which allows for estimation of the altitude at which GMW originated. In addition, crustal He accumulates in water over time, allowing for estimation of water residence times. Water samples were collected in the morning on selected dates in May and July 2011 at two locations about 200 m apart near the terminus area at altitudes between 2000 m and 2100 m. Eight samples were collected in six different days. Results show that the major source of subglacial meltwater is ASW rather than old, compressed glacial ice, which has a distinct noble gas signature not seen in our samples. Given that, GMW samples from the AG do deviate to a certain extent from the ASW values corresponding to measured water temperature and altitude at collection points. Two patterns are observed in the concentrations of the AG samples. The first one presents a relative Ar enrichment with respect to Ne, Kr, and Xe, first observed in high-altitude springs in the Galápagos Islands (Warrier et al., 2012). The second one displays a mass-dependent pattern, first observed in Michigan rainwater (Warrier et al., 2013). A preliminary Xe analysis indicates equilibration altitudes between 2500 m and 3400 m, values compatible with local topography. Samples present He excess of 4% to 91%, and suggest an average residence time of ~400 yrs. References:Warrier, R. B., Castro, M. C., and Hall, C. M. (2012), Recharge and source-water insights from the Galapagos Islands using noble gases and stable isotopes, Water Resour. Res., 48, W03508, doi:10.1029/2011WR010954. Warrier, R. B., Castro

  18. Noble Gas Analysis in the Quest to Find "Regolithic" Howardites

    NASA Technical Reports Server (NTRS)

    Cartwright, Julia A.; Hermann, S.; Herrin, J.; Mittlefehldt, D. W.; Ott, U.

    2011-01-01

    The howardite meteorites consist of approximately 200 polymict breccias of eucrite (basaltic) and diogenite (orthopyroxenitic) material (collectively, the HED group) that originate from the asteroid belt. Infrared reflectance spectroscopy of asteroids and laboratory studies of HEDs have indicated that the asteroid 4-Vesta is the likely parent body, and the partially-demolished south pole may be the source region. Asteroid regolith formation processes may be responsible for a number of observed petrological features including impact melt clasts, reworked clasts and mosaisicm. We have identified such features in a study of 30 howardites and polymict eucrites, and developed a regolith grading scheme based on petrology. However, the true regolithic nature of the howardite suite is not well defined, and previous research has suggested correlations between Ni contents of 300 - 1200 micron / g, a minimal variation in Al2O3 content around 8-9 wt% and the presence of solar wind noble gases are key hallmarks of an ancient regolith on Vesta . Through combined petrological, compositional and noble gas research, we aim to better understand howardite petrological diversity, regolith formation processes on parent asteroids, and to establish what defines a truly "regolithic" howardite. Our research will play an integral part in the interpretation of data gathered by the Dawn mission. Here we report the preliminary results from our noble gas analyses of four howardites: LEW 85313, EET 99408, MET 96500 and PCA 02066. Bulk major element compositional data have been collected, further petrological data for the HED group are reported by our colleagues, whilst trace-element analyses are underway. Our work will investigate the extent of whether previously described Ni, Al2O3 and noble gas characteristics are in fact indicative of a "regolithic" howardite.

  19. Isotopic and noble gas geochemistry in geothermal research

    SciTech Connect

    Kennedy, B.M.; DePaolo, D.J.

    1997-12-31

    The objective of this program is to provide, through isotopic analyses of fluids, fluid inclusions, and rocks and minerals coupled with improved methods for geochemical data analysis, needed information regarding sources of geothermal heat and fluids, the spatial distribution of fluid types, subsurface flow, water-rock reaction paths and rates, and the temporal evolution of geothermal systems. Isotopic studies of geothermal fluids have previously been limited to the light stable isotopes of H, C, and O. However, other isotopic systems such as the noble gases (He, Ne, Ar, Kr and Xe) and reactive elements (e.g. B, N, S, Sr and Pb) are complementary and may even be more important in some geothermal systems. The chemistry and isotopic composition of a fluid moving through the crust will change in space and time in response to varying chemical and physical parameters or by mixing with additional fluids. The chemically inert noble gases often see through these variations, making them excellent tracers for heat and fluid sources. Whereas, the isotopic compositions of reactive elements are useful tools in characterizing water-rock interaction and modeling the movement of fluids through a geothermal reservoir.

  20. Cryogenic method for measuring nuclides and fission gases

    DOEpatents

    Perdue, P.T.; Haywood, F.F.

    1980-05-02

    A cryogenic method is provided for determining airborne gases and particulates from which gamma rays are emitted. A special dewar counting vessel is filled with the contents of the sampling flask which is immersed in liquid nitrogen. A vertically placed sodium-iodide or germanium-lithium gamma-ray detector is used. The device and method are of particular use in measuring and identifying the radioactive noble gases including emissions from coal-fired power plants, as well as fission gases released or escaping from nuclear power plants.

  1. Noble gas isotopes in mineral springs within the Cascadia Forearc, Wasihington and Oregon

    USGS Publications Warehouse

    McCrory, Patricia A.; Constantz, James E.; Hunt, Andrew G.

    2014-01-01

    This U.S. Geological Survey report presents laboratory analyses along with field notes for a pilot study to document the relative abundance of noble gases in mineral springs within the Cascadia forearc of Washington and Oregon. Estimates of the depth to the underlying Juan de Fuca oceanic plate beneath the sample sites are derived from the McCrory and others (2012) slab model. Some of these springs have been previously sampled for chemical analyses (Mariner and others, 2006), but none currently have publicly available noble gas data. Helium isotope values as well as the noble gas values and ratios presented below will be used to determine the sources and mixing history of these mineral waters.

  2. Noble Gas Signatures in Groundwater and Rainwater on the Island of Maui, Hawaii - Developing a New Noble Gas Application in Fractured, Volcanic Systems

    NASA Astrophysics Data System (ADS)

    Castro, M. C.; Niu, Y.; Warrier, R. B.; Hall, C. M.; Gingerich, S. B.; Scholl, M. A.; Bouvier, L.

    2014-12-01

    Recent work in the Galapagos Islands suggests that noble gas temperatures (NGTs) in fractured groundwater systems reflect the temperature of the ground surface at the time of infiltration rather than the mean annual air temperature (MAAT) value as commonly assumed in sedimentary systems where NGTs are typically used as indicators of past climate. This suggests that noble gases in fractured areas may record seasonality, and thus, provide information about timing of recharge in addition to location. Calculation of NGTs assumes that rain-derived recharge at the water table is in equilibrium with ground air. Lack of noble gas equilibration with respect to surface conditions, however, was observed in high-altitude springs in the Galapagos Islands and in a rainwater pilot study in Michigan, supporting the NGT seasonality hypothesis. Developing this new NGT application will lead to a better understanding of fractured groundwater flow systems and will contribute to improved water resource management plans. This study, carried out on Maui, Hawaii, is meant to test these hypotheses while improving knowledge of this island's groundwater flow system where limited hydrologic data are available. Here, we present the first results of noble gas analyses from samples collected in springs, groundwater wells and rainwater on northeast Maui. Results show that like most Michigan rainwater samples, rainwater from Maui is in disequilibrium with surface conditions and follows a mass-dependent pattern. Spring samples follow a similar pattern to that of rainwater and suggest that spring water originates directly from rainfall. These findings further support the hypothesis of NGT seasonality. However, while the atmospheric composition of noble gases points to direct supply from rainfall to spring aquifer systems, a direct connection between spring water and deeper aquifer levels or the mantle is apparent from He isotopic ratios which display an almost pure He mantle component in some springs.

  3. Computational investigation of noble gas adsorption and separation by nanoporous materials.

    SciTech Connect

    Allendorf, Mark D.; Sanders, Joseph C.; Greathouse, Jeffery A.

    2008-10-01

    Molecular simulations are used to assess the ability of metal-organic framework (MOF) materials to store and separate noble gases. Specifically, grand canonical Monte Carlo simulation techniques are used to predict noble gas adsorption isotherms at room temperature. Experimental trends of noble gas inflation curves of a Zn-based material (IRMOF-1) are matched by the simulation results. The simulations also predict that IRMOF-1 selectively adsorbs Xe atoms in Xe/Kr and Xe/Ar mixtures at total feed gas pressures of 1 bar (14.7 psia) and 10 bar (147 psia). Finally, simulations of a copper-based MOF (Cu-BTC) predict this material's ability to selectively adsorb Xe and Kr atoms when present in trace amounts in atmospheric air samples. These preliminary results suggest that Cu-BTC may be an ideal candidate for the pre-concentration of noble gases from air samples. Additional simulations and experiments are needed to determine the saturation limit of Cu-BTC for xenon, and whether any krypton atoms would remain in the Cu-BTC pores upon saturation.

  4. Noble metal reforming of naphtha

    SciTech Connect

    Bonacci, J.C.; Patterson, J.R.

    1981-09-29

    Conventional noble metal reforming to upgrade the octane number of petroleum naphtha is an endothermic reaction which is carried out in a series of reactors with intermediate furnace heating of the petroleum fraction being upgraded. This specification discloses a process and apparatus configuration to increase the octane number of the reformate at a minimum liquid yield loss by cooling the first reforming stage effluent and then contacting the cooled effluent with a zsm-5 type zeolite catalyst prior to the first intermediate furnace heating.

  5. Noble Gas Inventory of Micrometeorites Collected at the Transantarctic Mountains (TAM) and Indications for Their Provenance

    NASA Technical Reports Server (NTRS)

    Ott, U.; Baecker, B.; Folco, L.; Cordier, C.

    2016-01-01

    A variety of processes have been considered possibly contributing the volatiles including noble gases to the atmospheres of the terrestrial planets (e.g., [1-3]). Special consideration has been given to the concept of accretion of volatile-rich materials by the forming planets. This might include infalling planetesimals and dust, and could include material from the outer asteroid belt, as well as cometary material from the outer solar system. Currently, the dominant source of extraterrestrial material accreted by the Earth is represented by micrometeorites (MMs) with sizes mostly in the 100-300 micron range [3, 4]). Their role has been assessed by [3], who conclude that accretion of early micrometeorites played a major role in the formation of the terrestrial atmosphere and oceans. We have therefore set out to investigate in more detail the inventory of noble gases in MMs. Here we summarize some of our results obtained on MMs collected in micrometeorite traps of the Transantarctic Mountains [5].

  6. The atmospheric inventory of Xenon and noble cases in shales The plastic bag experiment

    NASA Technical Reports Server (NTRS)

    Bernatowicz, T. J.; Podosek, F. A.; Honda, M.; Kramer, F. E.

    1984-01-01

    A novel trapped gas analysis protocol is applied to five shales in which the samples are sealed in air to eliminate the possibility of gas loss in the preanalysis laboratory vacuum exposure of a conventional protocol. The test is aimed at a determination concerning the hypothesis that atmospheric noble gases occur in the same proportion as planetary gases in meteorites, and that the factor-of-23 deficiency of air Xe relative to planetary Xe is made up by Xe stored in shales or other sedimentary rocks. The results obtained do not support the shale hypothesis.

  7. Noble Gas Thermometry and Hydrologic Ages: Evidence for Late Holocene Warming in Southwest Texas

    NASA Astrophysics Data System (ADS)

    Castro, M.; Goblet, P.

    2003-12-01

    Paleoclimatic reconstruction through the use of noble gases dissolved in groundwater has been the object of numerous studies in recent years. Unlike many other continental temperature proxies, noble gases have the advantage of providing direct information on atmospheric temperatures at the time rainwater penetrated the ground and joined a particular groundwater reservoir. In recent years, new methods for determination of noble gas temperatures have been developed, which provide a high level of accuracy on such temperature estimations. The issue of paleoclimatic reconstruction through noble gases however, is not only one of accurate temperature determination, but also one of accurate water age estimation so that a correct correspondence between noble gas temperatures and groundwater age can be established and proper paleoclimatic reconstruction attempted. The typical approach to estimate groundwater ages has been based on computing water travel times along streamlines from the recharge to the observation point taking into account only advection. This approach is limited because, like any other tracer, the movement of water in porous media is also affected by cinematic dispersion and molecular diffusion. We have therefore undertaken the formulation of hydrologic models that yield significantly better constraints on groundwater ages in the Carrizo aquifer and surrounding formations of south Texas, where noble gas temperatures have already been determined. To account for groundwater mixing we treat age as one would treat a solute concentration. In order to simulate groundwater ages we used a finite element model of groundwater flow that has been validated by 4He and 3He. The finite model spans a 120.6 Km cross-section between altitudes of +220m and -2210 m, and comprises 58,968 elements and 31,949 nodes. Combination of these newly calculated water ages and previously reported noble gas temperatures reveals new aspects of late Pleistocene and Holocene climate in

  8. Experimental evidence for high noble gas solubilities in silicate melts under mantle pressures

    NASA Astrophysics Data System (ADS)

    Schmidt, Burkhard C.; Keppler, Hans

    2002-02-01

    distribution. A geochemical consequence of our results is that noble gases remain incompatible elements at pressure conditions covering most of the upper mantle. Therefore partial melting remains an efficient process in extracting noble gases and other volatiles from the Earth's mantle.

  9. The Noble Gas Record of Gas-Water Phase Interaction in the Tight-Gas-Sand Reservoirs of the Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Ballentine, C. J.; Zhou, Z.; Harris, N. B.

    2015-12-01

    The mass of hydrocarbons that have migrated through tight-gas-sandstone systems before the permeability reduces to trap the hydrocarbon gases provides critical information in the hydrocarbon potential analysis of a basin. The noble gas content (Ne, Ar, Kr, Xe) of the groundwater has a unique isotopic and elemental composition. As gas migrates through the water column, the groundwater-derived noble gases partition into the hydrocarbon phase. Determination of the noble gases in the produced hydrocarbon phase then provides a record of the type of interaction (simple phase equilibrium or open system Rayleigh fractionation). The tight-gas-sand reservoirs of the Rocky Mountains represent one of the most significant gas resources in the United States. The producing reservoirs are generally developed in low permeability (averaging <0.1mD) Upper Cretaceous fluvial to marginal marine sandstones and commonly form isolated overpressured reservoir bodies encased in even lower permeability muddy sediments. We present noble gas data from producing fields in the Greater Green River Basin, Wyoming; the the Piceance Basin, Colorado; and in the Uinta Basin, Utah. The data is consistent from all three basins. We show how in each basin the noble gases record open system gas migration through a water column at maximum basin burial. The data within an open system model indicates that the gas now in-place represents the last ~10% of hydrocarbon gas to have passed through the water column, most likely prior to permeability closedown.

  10. Platinum-coated non-noble metal-noble metal core-shell electrocatalysts

    DOEpatents

    Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir

    2015-04-14

    Core-shell particles encapsulated by a thin film of a catalytically active metal are described. The particles are preferably nanoparticles comprising a non-noble core with a noble metal shell which preferably do not include Pt. The non-noble metal-noble metal core-shell nanoparticles are encapsulated by a catalytically active metal which is preferably Pt. The core-shell nanoparticles are preferably formed by prolonged elevated-temperature annealing of nanoparticle alloys in an inert environment. This causes the noble metal component to surface segregate and form an atomically thin shell. The Pt overlayer is formed by a process involving the underpotential deposition of a monolayer of a non-noble metal followed by immersion in a solution comprising a Pt salt. A thin Pt layer forms via the galvanic displacement of non-noble surface atoms by more noble Pt atoms in the salt. The overall process is a robust and cost-efficient method for forming Pt-coated non-noble metal-noble metal core-shell nanoparticles.

  11. Noble Gas Partitioning Behaviour During Mantle Melting: A Possible Explanation for 'The He Paradox'?

    NASA Astrophysics Data System (ADS)

    Brooker, R. A.; Heber, V.; Kelley, S. P.; Wood, B. J.

    2003-12-01

    New UVLAMP measurements of experimental noble gas crystal/melt partitioning values (including He) suggest reasonably incompatible behaviour for both olivine and cpx and no significant fractionation of noble gases relative to one another. This is consistent with models of noble gas incorporation at crystal lattice sites in both crystals (1). However the determined D values of approximately 8 x10-4 for cpx and 5 x10-3 for olivine suggest a small but significant amount of noble gas might be retained in the mantle after melting. It is also apparent that He is three orders of magnitude less incompatible than U and Th in olivine. As opx is predicted to show similar characteristic to olivine, melting to produce a highly depleted harzbugitic (low-cpx) mantle would involve the preferential removal of U+Th relative to He. This in turn would allow a relatively undisturbed primordial/radiogenic 3He/4He ratio to be retained in association with low He abundance. Thus, recycling of previously depleted mantle into the source region of 'hot spots' provides one possible explanation for the paradox of high 3/4 He ratios previously thought to indicate an undegassed, primordial lower mantle reservoir, with low He abundance indicating a degassed source (2). Preliminary UVLAMP depth profiles for noble gas diffusion in mantle minerals confirm that although sub-solidus diffusive removal of He relative to other noble gases from a gas-rich mantle plum is theoretically possible, the short distances involved are unlikely to produce an effect that can be sustained though a hot spot melting event. The slow diffusion rates and lack of fractionation of noble gases in our partitioning experiments suggests that low He/Ar (and Ne/Ar) ratios observed at hot spots are most likely to be features inherited from the source, or subsequently imposed by some shallow level process. In our partitioning experiments, it proved surprisingly difficult to grow olivine crystals that are free of bubbles, even from

  12. Structural Measurements from Images of Noble Gas Diffusion

    NASA Astrophysics Data System (ADS)

    Cadman, Robert V.; Kadlecek, Stephen J.; Emami, Kiarash; MacDuffie Woodburn, John; Vahdat, Vahid; Ishii, Masaru; Rizi, Rahim R.

    2009-03-01

    Magnetic resonance imaging of externally polarized noble gases such as ^3He has been used for pulmonary imaging for more than a decade. Because gas diffusion is impeded by the alveoli, the diffusion coefficient of gas in the lung, measured on a time scale of milliseconds, is reduced compared to that of the same gas mixture in the absence of restrictions. When the alveolar walls decay, as in emphysema, diffusivity in the lung increases. In this paper, the relationship between diffusion measurements and the size of the restricting structures will be discussed. The simple case of diffusion in an impermeable cylinder, a structure similar to the upper respiratory airways in mammals, has been studied. A procedure will be presented by which airways of order 2 mm in diameter may be accurately measured; demonstration experiments with plastic tubes will also be presented. The additional developments needed before this technique becomes practical will be briefly discussed.

  13. Incorporation of noble metals into aerogels

    DOEpatents

    Hair, L.M.; Sanner, R.D.; Coronado, P.R.

    1998-12-22

    Aerogels or xerogels containing atomically dispersed noble metals for applications such as environmental remediation are disclosed. New noble metal precursors, such as Pt--Si or Pd(Si--P){sub 2}, have been created to bridge the incompatibility between noble metals and oxygen, followed by their incorporation into the aerogel or xerogel through sol-gel chemistry and processing. Applications include oxidation of hydrocarbons and reduction of nitrogen oxide species, complete oxidation of volatile organic carbon species, oxidative membranes for photocatalysis and partial oxidation for synthetic applications.

  14. Incorporation of noble metals into aerogels

    DOEpatents

    Hair, Lucy M.; Sanner, Robert D.; Coronado, Paul R.

    1998-01-01

    Aerogels or xerogels containing atomically dispersed noble metals for applications such environmental remediation. New noble metal precursors, such as Pt--Si or Pd(Si--P).sub.2, have been created to bridge the incompatibility between noble metals and oxygen, followed by their incorporation into the aerogel or xerogel through sol-gel chemistry and processing. Applications include oxidation of hydrocarbons and reduction of nitrogen oxide species, complete oxidation of volatile organic carbon species, oxidative membranes for photocatalysis and partial oxidation for synthetic applications.

  15. Recovery and use of fission product noble metals

    SciTech Connect

    Jensen, G.A.; Rohmann, C.A.; Perrigo, L.D.

    1980-06-01

    Noble metals in fission products are of strategic value. Market prices for noble metals are rising more rapidly than recovery costs. A promising concept has been developed for recovery of noble metals from fission product waste. Although the assessment was made only for the three noble metal fission products (Rh, Pd, Ru), there are other fission products and actinides which have potential value. (DLC)

  16. 21 CFR 872.3060 - Noble metal alloy.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Noble metal alloy. 872.3060 Section 872.3060 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3060 Noble metal alloy. (a) Identification. A noble metal alloy is a device composed primarily of noble metals, such as gold, palladium, platinum, or silver,...

  17. 21 CFR 872.3060 - Noble metal alloy.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Noble metal alloy. 872.3060 Section 872.3060 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3060 Noble metal alloy. (a) Identification. A noble metal alloy is a device composed primarily of noble metals, such as gold, palladium, platinum, or silver,...

  18. 21 CFR 872.3060 - Noble metal alloy.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Noble metal alloy. 872.3060 Section 872.3060 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3060 Noble metal alloy. (a) Identification. A noble metal alloy is a device composed primarily of noble metals, such as gold, palladium, platinum, or silver,...

  19. 21 CFR 872.3060 - Noble metal alloy.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Noble metal alloy. 872.3060 Section 872.3060 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3060 Noble metal alloy. (a) Identification. A noble metal alloy is a device composed primarily of noble metals, such as gold, palladium, platinum, or silver,...

  20. 21 CFR 872.3060 - Noble metal alloy.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Noble metal alloy. 872.3060 Section 872.3060 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3060 Noble metal alloy. (a) Identification. A noble metal alloy is a device composed primarily of noble metals, such as gold, palladium, platinum, or silver,...

  1. Noble gas partitioning behavior in the Sleipner Vest hydrocarbon field

    NASA Astrophysics Data System (ADS)

    Barry, P. H.; Lawson, M.; Warr, O.; Mabry, J.; Byrne, D. J.; Meurer, W. P.; Ballentine, C. J.

    2015-12-01

    Noble gases are chemically inert and variably soluble in crustal fluids. They are primarily introduced into hydrocarbon reservoirs through exchange with formation waters, and can be used to assess migration pathways, mechanisms and reservoir storage. Of particular interest is the role groundwater plays in hydrocarbon transport, which is reflected in hydrocarbon-water volume ratios. We present compositional, stable isotope and noble gas isotope and abundance data from the Sleipner Vest field, in the Norwegian North Sea. Sleipner gases are generated from primary cracking of kerogen and the thermal cracking of oil, sourced from type II marine source, with relatively homogeneous maturities and a range in vitrinite reflectance (1.2-1.7%). Gases are hosted in the lower shoreface sandstones of the Jurassic Hugin formation, which is sealed by the Jurassic Upper Draupne and Heather formations. Gases are composed of N2 (0.6-0.9%), CO2 (5.4-15.3%) and hydrocarbons (69-80%). Helium isotopes (3He/4He) are radiogenic and range from 0.065 to 0.116 RA, showing a small mantle contribution, consistent with Ne isotopes (20Ne/22Ne from 9.70-9.91; 21Ne/22Ne from 0.0290-0.0344) and Ar isotopes (40Ar/36Ar from 315-489). 20Ne/36Ar, 84Kr/36Ar and 132Xe/36Ar values are systematically higher relative to air saturated water ratios. These data are discussed within the framework of several conceptual models: i) Total gas-stripping model, which defines the minimum volume of water to have interacted with the hydrocarbon phase; ii) Equilibrium model, assuming simple equilibration between groundwater and hydrocarbon phase at reservoir P,T and salinity; and iii) Open and closed system gas-stripping models. Using Ne-Ar, we estimate gas-water ratios for the Sleipner system of 0.02-0.09, which compare with geologic gas-water estimates of ~0.24, and suggest more groundwater interaction than a static system estimate. Kr and Xe show evidence for an additional source or process involving oil or sediments.

  2. Physiological response of rats to delivery of helium and xenon: implications for hyperpolarized noble gas imaging

    NASA Technical Reports Server (NTRS)

    Ramirez, M. P.; Sigaloff, K. C.; Kubatina, L. V.; Donahue, M. A.; Venkatesh, A. K.; Albert, M. S.; ALbert, M. S. (Principal Investigator)

    2000-01-01

    The physiological effects of various hyperpolarized helium and xenon MRI-compatible breathing protocols were investigated in 17 Sprague-Dawley rats, by continuous monitoring of blood oxygen saturation, heart rate, EKG, temperature and endotracheal pressure. The protocols included alternating breaths of pure noble gas and oxygen, continuous breaths of pure noble gas, breath-holds of pure noble gas for varying durations, and helium breath-holds preceded by two helium rinses. Alternate-breath protocols up to 128 breaths caused a decrease in oxygen saturation level of less than 5% for either helium or xenon, whereas 16 continuous-breaths caused a 31.5% +/- 2.3% decrease in oxygen saturation for helium and a 30.7% +/- 1. 3% decrease for xenon. Breath-hold protocols up to 25 s did not cause the oxygen saturation to fall below 90% for either of the noble gases. Oxygen saturation values below 90% are considered pathological. At 30 s of breath-hold, the blood oxygen saturation dropped precipitously to 82% +/- 0.6% for helium, and to 76.5% +/- 7. 4% for xenon. Breath-holds longer than 10 s preceded by pre-rinses caused oxygen saturation to drop below 90%. These findings demonstrate the need for standardized noble gas inhalation procedures that have been carefully tested, and for continuous physiological monitoring to ensure the safety of the subject. We find short breath-hold and alternate-breath protocols to be safe procedures for use in hyperpolarized noble gas MRI experiments. Copyright 2000 John Wiley & Sons, Ltd.

  3. Noble metal superparticles and methods of preparation thereof

    DOEpatents

    Sun, Yugang; Hu, Yongxing

    2016-07-12

    A method comprises heating an aqueous solution of colloidal silver particles. A soluble noble metal halide salt is added to the aqueous solution which undergoes a redox reaction on a surface of the silver particles to form noble metal/silver halide SPs, noble metal halide/silver halide SPs or noble metal oxide/silver halide SPs on the surface of the silver particles. The heat is maintained for a predetermined time to consume the silver particles and release the noble metal/silver halide SPs, the noble metal halide/silver halide SPs or the noble metal oxide/silver halide SPs into the aqueous solution. The aqueous solution is cooled. The noble metal/silver halide SPs, the noble metal halide/silver halide SPs or noble metal oxide/silver halide SPs are separated from the aqueous solution. The method optionally includes adding a soluble halide salt to the aqueous solution.

  4. Neutron detection by scintillation of noble-gas excimers

    NASA Astrophysics Data System (ADS)

    McComb, Jacob Collin

    Neutron detection is a technique essential to homeland security, nuclear reactor instrumentation, neutron diffraction science, oil-well logging, particle physics and radiation safety. The current shortage of helium-3, the neutron absorber used in most gas-filled proportional counters, has created a strong incentive to develop alternate methods of neutron detection. Excimer-based neutron detection (END) provides an alternative with many attractive properties. Like proportional counters, END relies on the conversion of a neutron into energetic charged particles, through an exothermic capture reaction with a neutron absorbing nucleus (10B, 6Li, 3He). As charged particles from these reactions lose energy in a surrounding gas, they cause electron excitation and ionization. Whereas most gas-filled detectors collect ionized charge to form a signal, END depends on the formation of diatomic noble-gas excimers (Ar*2, Kr*2,Xe* 2) . Upon decaying, excimers emit far-ultraviolet (FUV) photons, which may be collected by a photomultiplier tube or other photon detector. This phenomenon provides a means of neutron detection with a number of advantages over traditional methods. This thesis investigates excimer scintillation yield from the heavy noble gases following the boron-neutron capture reaction in 10B thin-film targets. Additionally, the thesis examines noble-gas excimer lifetimes with relationship to gas type and gas pressure. Experimental data were collected both at the National Institute of Standards and Technology (NIST) Center for Neutron Research, and on a newly developed neutron beamline at the Maryland University Training Reactor. The components of the experiment were calibrated at NIST and the University of Maryland, using FUV synchrotron radiation, neutron imaging, and foil activation techniques, among others. Computer modeling was employed to simulate charged-particle transport and excimer photon emission within the experimental apparatus. The observed excimer

  5. On a cryogenic noble gas ion catcher

    NASA Astrophysics Data System (ADS)

    Dendooven, P.; Purushothaman, S.; Gloos, K.

    2006-03-01

    In situ purification of the gas used as stopping medium in a noble gas ion catcher by operating the device at low temperatures of 60-150 K was investigated. Alpha-decay recoil ions from a 223Ra source served as energetic probes. The combined ion survival and transport efficiencies for 219Rn ions saturated below about 90 K, reaching 28.7(17)% in helium, 22.1(13)% in neon, and 17.0(10)% in argon. These values may well reflect the charge exchange and stripping cross-sections during the slowing down of the ions, and thus represent a fundamental upper limit for the efficiency of noble gas ion catcher devices. We suggest the cryogenic noble gas ion catcher as a technically simpler alternative to the ultra-high purity noble gas ion catcher operating at room temperature.

  6. A model to explain the various paradoxes associated with mantle noble gas geochemistry

    PubMed Central

    Anderson, Don L.

    1998-01-01

    As a result of an energetic accretion, the Earth is a volatile-poor and strongly differentiated planet. The volatile elements can be accounted for by a late veneer (≈1% of total mass of the Earth). The incompatible elements are strongly concentrated into the exosphere (atmosphere, oceans, sediments, and crust) and upper mantle. Recent geochemical models invoke a large primordial undegassed reservoir with chondritic abundances of uranium and helium, which is clearly at odds with mass and energy balance calculations. The basic assumption behind these models is that excess “primordial” 3He is responsible for 3He/4He ratios higher than the average for midocean ridge basalts. The evidence however favors depletion of 3He and excessive depletion of 4He and, therefore, favors a refractory, residual (low U, Th) source Petrological processes such as melt-crystal and melt-gas separation fractionate helium from U and Th and, with time, generate inhomogeneities in the 3He/4He ratio. A self-consistent model for noble gases involves a gas-poor planet with trapping of CO2 and noble gases in the shallow mantle. Such trapped gases are released by later tectonic and magmatic processes. Most of the mantle was depleted and degassed during the accretion process. High 3He/4He gases are viewed as products of ancient gas exsolution stored in low U environments, rather than products of primordial reservoirs. PMID:9689038

  7. Noble gas sputtering calculations using TRIM

    SciTech Connect

    Greene, J.P.; Nemanich, J.; Thomas, G.E.; Schiel, S.L.

    1996-12-31

    In conjunction with our experimental work on saddle field ion sputtering, we have attempted to apply the Monte Carlo program TRIM (Transport of Ions in Matter) to calculate the sputter yields for a variety of noble gas sputtering applications. Comparison with experiments are shown. Information extracted from these analyses have proved useful in optimizing the experimental sputtering parameters. Calculated sputter yields obtained utilizing TRIM are presented for noble gas sputtering of a variety of materials common to nuclear target production.

  8. New interatomic potentials for studying the behavior of noble gas atoms in tungsten

    NASA Astrophysics Data System (ADS)

    Zhou, Fen; Fang, Jingzhong; Deng, Huiqiu; Liu, Jianglong; Xiao, Shifang; Shu, Xiaolin; Gao, Fei; Hu, Wangyu

    2015-12-01

    To study the behavior of noble gas atoms (He, Ne and Ar) in bulk tungsten, new DFT-based potentials for W-He, W-Ne and W-Ar interactions were developed by fitting the results obtained from density functional theory calculations. The new potentials adopt the embedded atom method (EAM) formalism, and the "s-band model" is used to describe the many-body interactions between each of the noble gas atoms and its neighboring W atoms. These potentials reproduce the formation energies of point defects and the migration barriers of single noble gas atoms. The simulations using these potentials successfully predict that the tetrahedral interstitial site is more stable than the octahedral interstitial site for X (= He, Ne or Ar) interstitials. Based on these new potentials, the binding interactions of a single X atom with the Xn and Xn-Vacancy clusters and the diffusion properties of Xn clusters in bulk W were studied using molecular dynamics (MD) simulations. The present results indicate that the binding energies obtained using the new potentials are good in agreement with the results of DFT calculations. The migration energies of the clusters increase with both the increase in the atomic radius of noble gases and the increase in the size of the clusters.

  9. Synthesis of noble metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Bahadory, Mozhgan

    Improved methods were developed for the synthesis of noble metal nanoparticles. Laboratory experiments were designed for introducing of nanotechnology into the undergraduate curriculum. An optimal set of conditions for the synthesis of clear yellow colloidal silver was investigated. Silver nanoparticles were obtained by borohydride reduction of silver nitrate, a method which produces particles with average size of 12+/-2 nm, determined by Transmission Electron Microscopy (TEM). The plasmon absorbance is at 397 nm and the peak width at half maximum (PWHM) is 70-75 nm. The relationship between aggregation and optical properties was determined along with a method to protect the particles using polyvinylpyrrolidone (PVP). A laboratory experiment was designed in which students synthesize yellow colloidal silver, estimate particle size using visible spectroscopy, and study aggregation effects. The synthesis of the less stable copper nanoparticles is more difficult because copper nanopaticles are easily oxidized. Four methods were used for the synthesis of copper nanoparticles, including chemical reduction with sodium borohydride, sodium borohydride with potassium iodide, isopropyl alcohol with cetyltrimethylammonium bormide (CTAB) and reducing sugars. The latter method was also the basis for an undergraduate laboratory experiment. For each reaction, the dependence of stability of the copper nanoparticles on reagent concentrations, additives, relative amounts of reactants, and temperature is explored. Atomic force microscopy (AFM), TEM and UV-Visible Spectroscopy were used to characterize the copper nanoparticles. A laboratory experiment to produce copper nanoparticles from household chemicals was developed.

  10. ABOUT THE POSSIBLE ROLE OF HYDROCARBON LAKES IN THE ORIGIN OF TITAN'S NOBLE GAS ATMOSPHERIC DEPLETION

    SciTech Connect

    Cordier, D.; Mousis, O.; Lebonnois, S.; Lavvas, P.; Lobo, L. Q.; Ferreira, A. G. M.

    2010-10-01

    An unexpected feature of Titan's atmosphere is the strong depletion in primordial noble gases revealed by the Gas Chromatograph Mass Spectrometer aboard the Huygens probe during its descent on 2005 January 14. Although several plausible explanations have already been formulated, no definitive response to this issue has yet been found. Here, we investigate the possible sequestration of these noble gases in the liquid contained in lakes and wet terrains on Titan and the consequences for their atmospheric abundances. Considering the atmosphere and the liquid existing on the soil as a whole system, we compute the abundance of each noble gas relative to nitrogen. To do so, we make the assumption of thermodynamic equilibrium between the liquid and the atmosphere, the abundances of the different constituents being determined via regular solution theory. We find that xenon's atmospheric depletion can be explained by its dissolution at ambient temperature in the liquid presumably present on Titan's soil. In the cases of argon and krypton, we find that the fractions incorporated in the liquid are negligible, implying that an alternative mechanism must be invoked to explain their atmospheric depletion.

  11. Noble gas measurements from tiny water amounts: fluid inclusions in carbonates of speleothemes and coral skeletons

    NASA Astrophysics Data System (ADS)

    Papp, Laszlo; Palcsu, Laszlo; Major, Zoltan

    2010-05-01

    Based on the concentrations of dissolved noble gases in fluid inclusions in speleothems and corals, noble gas temperatures (NGT) might be derived, that would be important climate information [1]. In the case of terrestrial carbonates, it means that the temperature dependency of noble gases in the evolving fluid inclusions is suitable to determine the prevailing temperature. This recognition provides new opportunities for the research of paleoclimate. Additionally, the dissolved noble gases in the fluid inclusions represented in corals could be used to study past sea surface temperatures that are one of the most essential parameter of climate reconstructions. To measure dissolved noble gases in fluid inclusions of a few micro-litres, a noble gas mass spectrometer equipped with an ultra high vacuum preparation line is the most suitable way. The preparation of the carbonate samples is performed in a sample preparation system connected to a static mode VG 5400 noble gas mass spectrometer. As a first step of the sample preparation, one piece of a sample is put into a crusher of the preparation line and then evacuated and heated at night. The crushing of dripstone and coral samples is carried out in a stainless steel pipe with a ferro-magnetic ball at 150 °C temperature, in such a way that the ball is kept on elevating and falling down onto the carbonate sample one hundred times. The aim of the heating is to avoid the water released from the fluid inclusions not to be adsorbed on the surface of the freshly broken carbonate [2]. The water released from the fluid inclusions is frozen into a cold finger, being held at temperature of -70 °C for 15 minutes. In this case, the collection efficiency is better than 99.7 %. Then the cold finger is warmed to 27 °C, and the pressure of the water vapour expanded to the volume of the cold finger is determined by a pressure gauge, which accuracy is better than 0.2 % in the pressure range of 10-2 mbar to 11 mbar. The water vapour

  12. CO-oxidation catalysts: Low-temperature CO oxidation over Noble-Metal Reducible Oxide (NMRO) catalysts

    NASA Technical Reports Server (NTRS)

    Herz, Richard K.

    1990-01-01

    Oxidation of CO to CO2 is an important reaction technologically and environmentally and a complex and interesting reaction scientifically. In most cases, the reaction is carried out in order to remove CO as an environmental hazard. A major application of heterogeneous catalysts is catalytic oxidation of CO in the exhaust of combustion devices. The reaction over catalysts in exhaust gas is fast and often mass-transfer-limited since exhaust gases are hot and O2/CO ratios are high. The main challenges to catalyst designers are to control thermal sintering and chemical poisoning of the active materials. The effect of the noble metal on the oxide is discussed, followed by the effect of the oxide on the noble metal, the interaction of the noble metal and oxide to form unique catalytic sites, and the possible ways in which the CO oxidation reaction is catalyzed by the NMRO materials.

  13. Rare gases systematics and mantle structure

    NASA Technical Reports Server (NTRS)

    Allegre, C. J.; Staudacher, T.

    1994-01-01

    The following points are emphasized: one of the most important ones is certainly the first set of experimental data on the solubility of noble gases in metal phases at intermediate pressures, since the core was certainly not formed at ultra high pressures, as emphasized by Ahrens and confirmed by trace elements systematics Wanke. The experimental data clearly show that the core can not be a major reservoir for terrestrial rare gases; the second point is a more elaborate reconsideration of the (40)K-(40)Ar budget of the Earth. This shows that (40)Ar contained in continental crust plus upper mantle plus atmosphere is at maximum half of the (40)Ar inventory of the whole earth. This implies the existence of a two layered mantle; the third point is the discovery by the Australian noble gases group of the existence of high (20)Ne/(22)Ne and low (21)Ne/(22)Ne isotopic ratios in Loihi seamount samples. This results which are different to the MORB ratios confirm the idea of a two layered model, but suggest the existence of a primordial solar type Ne reservoir. Several possibilities about the origin of this (20)Ne excess in the mantle will be discussed; The high (40)Ar/(36)Ar, (129)Xe/(130)Xe and (134) Xe/(130)Xe, (136)Xe/(130)Xe are confirmed by new data. The corresponding ratios for the lower mantle will be discussed. (40)Ar/(36)Ar ratios up to 6000 can be accepted and will not modify the general model of the mantle. They confirm the atmosphere chronology, about 85 percent of the atmosphere was formed in the first 50 My and 15 percent later on.

  14. Noble gas contents of shergottites and implications for the Martian origin of SNC meteorites

    NASA Astrophysics Data System (ADS)

    Bogard, D. D.; Nyquist, L. E.; Johnson, P.

    1984-09-01

    Three meteorites belonging to the rare group of SNC achondrites, which may have originated in the planet Mars, have been subjected to noble gas isotopic concentration measurements. The elemental and isotopic ratios obtained are unlike those for any other noble gas components except those obtained in analyses of the Martian atmosphere by Viking spacecraft. It is hypothesized that the Kr and Xe gases represent a portion of the Martian atmosphere which was shock-implanted in the case of Elephant Moraine A79001, and that they constitute direct evidence of a Martian origin for the shergottite meteorites. If the SNC meteorites were ejected from Mars at the shergottite shock age of about 180 My ago, they must have been objects more than 6 m in diameter which experienced at least three space collisions to initiate cosmic ray exposure.

  15. Noble gas contents of shergottites and implications for the Martian origin of SNC meteorites

    NASA Technical Reports Server (NTRS)

    Bogard, D. D.; Nyquist, L. E.; Johnson, P.

    1984-01-01

    Three meteorites belonging to the rare group of SNC achondrites, which may have originated in the planet Mars, have been subjected to noble gas isotopic concentration measurements. The elemental and isotopic ratios obtained are unlike those for any other noble gas components except those obtained in analyses of the Martian atmosphere by Viking spacecraft. It is hypothesized that the Kr and Xe gases represent a portion of the Martian atmosphere which was shock-implanted in the case of Elephant Moraine A79001, and that they constitute direct evidence of a Martian origin for the shergottite meteorites. If the SNC meteorites were ejected from Mars at the shergottite shock age of about 180 My ago, they must have been objects more than 6 m in diameter which experienced at least three space collisions to initiate cosmic ray exposure.

  16. Noble gas composition and 40Ar/39Ar age in eclogites from the main hole of the Chinese Continental Scientific Drilling project

    NASA Astrophysics Data System (ADS)

    Hopp, Jens; Schwarz, Winfried H.; Trieloff, Mario; Meyer, Hans-Peter; Hanel, Michael; Altherr, Rainer

    2016-10-01

    We present the first comprehensive noble gas study on eclogites. The four eclogite samples were recovered during the Chinese Continental Scientific Drilling and are from two distinct profile depth sections differing in their degree of interaction with meteoric water, based on their δ 18O-values (surface related and of mantle-type). Hence, noble gas analyses offer the potential to further discriminate between shallow (meteoric) and deep (mantle) fluid sources. Noble gas compositions reveal typical crustal fluid compositions, characterized by a variable mixture of atmospheric gases with significant contributions of nucleogenic neon, radiogenic 4He*, radiogenic 40Ar*, fissiogenic 131-136Xe, and presumably bariogenic 131Xe, but no significant addition of mantle gases. This signature can be also considered to represent one endmember component of eclogitic diamonds. Concentrations of non-radiogenic noble gases are rather low, with depletion of light relative to the heavier noble gases. Eclogites from lower depth which experienced a higher degree of interaction with meteoric water also showed higher contributions of atmospheric gas compared with eclogites recovered from greater depth. This is interpreted to result from interaction with high-salinity fluids during ultrahigh pressure (UH P). It demonstrates that the atmospheric noble gas abundance is a proxy for interaction with surface related fluids. 40Ar/39Ar (inverse) isochron ages of two phengite separates (241.2 ± 0.4 Ma and 275.0 ± 1.8 Ma, 1 σ-errors) predate the main phase of UH P metamorphism (ca. 220 Ma). Biotite yields an integrated age of about 1100 Ma. These age values are interpreted to reflect the likely addition of excess 40Ar without any chronological meaning.

  17. Issues Involving The OSI Concept of Operation For Noble Gas Radionuclide Detection

    SciTech Connect

    Carrigan, C R; Sun, Y

    2011-01-21

    The development of a technically sound protocol for detecting the subsurface release of noble gas radionuclides is critical to the successful operation of an on site inspection (OSI) under the CTBT and has broad ramifications for all aspects of the OSI regime including the setting of specifications for both sampling and analysis equipment used during an OSI. With NA-24 support, we are investigating a variety of issues and concerns that have significant bearing on policy development and technical guidance regarding the detection of noble gases and the creation of a technically justifiable OSI concept of operation. The work at LLNL focuses on optimizing the ability to capture radioactive noble gases subject to the constraints of possible OSI scenarios. This focus results from recognizing the difficulty of detecting gas releases in geologic environments - a lesson we learned previously from the LLNL Non-Proliferation Experiment (NPE). Evaluation of a number of important noble gas detection issues, potentially affecting OSI policy, has awaited the US re-engagement with the OSI technical community. Thus, there have been numerous issues to address during the past 18 months. Most of our evaluations of a sampling or transport issue necessarily involve computer simulations. This is partly due to the lack of OSI-relevant field data, such as that provided by the NPE, and partly a result of the ability of LLNL computer-based models to test a range of geologic and atmospheric scenarios far beyond what could ever be studied in the field making this approach very highly cost effective. We review some highlights of the transport and sampling issues we have investigated during the past year. We complete the discussion of these issues with a description of a preliminary design for subsurface sampling that is intended to be a practical solution to most if not all the challenges addressed here.

  18. Noble gas tracers of ventilation during deep-water formation in the Weddell Sea

    NASA Astrophysics Data System (ADS)

    Nicholson, D. P.; Khatiwala, S.; Heimbach, P.

    2016-05-01

    To explore the dynamics and implications of incomplete air-sea equilibration during the formation of abyssal water masses, we simulated noble gases in the Estimating the Circulation & Climate of the Ocean (ECCO) global ocean state estimate. A novel computation approach utilizing a matrix-free Newton-Krylov (MFNK) scheme was applied to quickly compute the periodic seasonal solutions for noble gas tracers. MFNK allows for quick computation of a cyclo-stationary solution for tracers (i.e., a spun-up, repeating seasonal cycle), which would otherwise be computationally infeasible due to the long time scale of dynamic adjustment of the abyssal ocean (1000’s of years). A suite of experiments isolates individual processes, including atmospheric pressure effects, the solubility pump and air-sea bubble fluxes. In addition to these modeled processes, a volumetric contribution of 0.28 ± 0.07% of glacial melt water is required to reconcile deep-water observations in the Weddell Sea. Another primary finding of our work is that the saturation anomaly of heavy noble gases in model simulations is in excess of two-fold more negative than is suggested from Weddell Sea observations. This result suggests that model water masses are insufficiently ventilated prior to subduction and thus there is insufficient communication between atmosphere and ocean at high latitudes. The discrepancy between noble gas observations and ECCO simulations highlights that important inadequacies remain in how we model high-latitude ventilation with large implications for the oceanic uptake and storage of carbon.

  19. Noble Gas Analysis for Mars Robotic Missions: Evaluating K-Ar Age Dating for Mars Rock Analogs and Martian Shergottites

    NASA Technical Reports Server (NTRS)

    Park, J.; Ming, D. W.; Garrison, D. H.; Jones, J. H.; Bogard, D. D.; Nagao, K.

    2009-01-01

    The purpose of this noble gas investigation was to evaluate the possibility of measuring noble gases in martian rocks and air by future robotic missions such as the Mars Science Laboratory (MSL). The MSL mission has, as part of its payload, the Sample Analysis at Mars (SAM) instrument, which consists of a pyrolysis oven integrated with a GCMS. The MSL SAM instrument has the capability to measure noble gas compositions of martian rocks and atmosphere. Here we suggest the possibility of K-Ar age dating based on noble gas release of martian rocks by conducting laboratory simulation experiments on terrestrial basalts and martian meteorites. We provide requirements for the SAM instrument to obtain adequate noble gas abundances and compositions within the current SAM instrumental operating conditions, especially, a power limit that prevents heating the furnace above approx.1100 C. In addition, Martian meteorite analyses from NASA-JSC will be used as ground truth to evaluate the feasibility of robotic experiments to constrain the ages of martian surface rocks.

  20. Separation of polar gases from nonpolar gases

    DOEpatents

    Kulprathipanja, S.; Kulkarni, S.S.

    1986-08-26

    Polar gases such as hydrogen sulfide, sulfur dioxide and ammonia may be separated from nonpolar gases such as methane, nitrogen, hydrogen or carbon dioxide by passing a mixture of polar and nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The use of such membranes as exemplified by polyethylene glycol and silicon rubber composited on polysulfone will permit greater selectivity accompanied by a high flux rate in the separation process.

  1. Separation of polar gases from nonpolar gases

    DOEpatents

    Kulprathipanja, Santi; Kulkarni, Sudhir S.

    1986-01-01

    Polar gases such as hydrogen sulfide, sulfur dioxide and ammonia may be separated from nonpolar gases such as methane, nitrogen, hydrogen or carbon dioxide by passing a mixture of polar and nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The use of such membranes as exemplified by polyethylene glycol and silicon rubber composited on polysulfone will permit greater selectivity accompanied by a high flux rate in the separation process.

  2. Separation of polar gases from nonpolar gases

    DOEpatents

    Kulprathipanja, Santi

    1986-01-01

    The separation of polar gases from nonpolar gases may be effected by passing a mixture of nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The porous support is pretreated prior to casting of the mixture thereon by contact with a polyhydric alcohol whereby the pores of the support are altered, thus adding to the increased permeability of the polar gas.

  3. Separation of polar gases from nonpolar gases

    DOEpatents

    Kulprathipanja, S.

    1986-08-19

    The separation of polar gases from nonpolar gases may be effected by passing a mixture of nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The porous support is pretreated prior to casting of the mixture thereon by contact with a polyhydric alcohol whereby the pores of the support are altered, thus adding to the increased permeability of the polar gas.

  4. Noble Metal Nanoparticles for Biosensing Applications

    PubMed Central

    Doria, Gonçalo; Conde, João; Veigas, Bruno; Giestas, Leticia; Almeida, Carina; Assunção, Maria; Rosa, João; Baptista, Pedro V.

    2012-01-01

    In the last decade the use of nanomaterials has been having a great impact in biosensing. In particular, the unique properties of noble metal nanoparticles have allowed for the development of new biosensing platforms with enhanced capabilities in the specific detection of bioanalytes. Noble metal nanoparticles show unique physicochemical properties (such as ease of functionalization via simple chemistry and high surface-to-volume ratios) that allied with their unique spectral and optical properties have prompted the development of a plethora of biosensing platforms. Additionally, they also provide an additional or enhanced layer of application for commonly used techniques, such as fluorescence, infrared and Raman spectroscopy. Herein we review the use of noble metal nanoparticles for biosensing strategies—from synthesis and functionalization to integration in molecular diagnostics platforms, with special focus on those that have made their way into the diagnostics laboratory. PMID:22438731

  5. Optimizing detection of noble gas emission at a former UNE site: sample strategy, collection, and analysis

    NASA Astrophysics Data System (ADS)

    Kirkham, R.; Olsen, K.; Hayes, J. C.; Emer, D. F.

    2013-12-01

    Underground nuclear tests may be first detected by seismic or air samplers operated by the CTBTO (Comprehensive Nuclear-Test-Ban Treaty Organization). After initial detection of a suspicious event, member nations may call for an On-Site Inspection (OSI) that in part, will sample for localized releases of radioactive noble gases and particles. Although much of the commercially available equipment and methods used for surface and subsurface environmental sampling of gases can be used for an OSI scenario, on-site sampling conditions, required sampling volumes and establishment of background concentrations of noble gases require development of specialized methodologies. To facilitate development of sampling equipment and methodologies that address OSI sampling volume and detection objectives, and to collect information required for model development, a field test site was created at a former underground nuclear explosion site located in welded volcanic tuff. A mixture of SF-6, Xe127 and Ar37 was metered into 4400 m3 of air as it was injected into the top region of the UNE cavity. These tracers were expected to move towards the surface primarily in response to barometric pumping or through delayed cavity pressurization (accelerated transport to minimize source decay time). Sampling approaches compared during the field exercise included sampling at the soil surface, inside surface fractures, and at soil vapor extraction points at depths down to 2 m. Effectiveness of various sampling approaches and the results of tracer gas measurements will be presented.

  6. Electron-beam generation in a wide-aperture open gas discharge: A comparative study for different inert gases

    SciTech Connect

    Bokhan, P. A.; Zakrevsky, Dm. E.

    2010-08-30

    In the present study, electron-beam generation by open discharges was examined. The study was performed at gas pressures up to 20 Torr, and covered all inert gases. At voltages up to 8 kV, electron-beam currents up to 1600 A with current density {approx}130 A/cm{sup 2} and a beam generation efficiency in excess of 93% were obtained. The production of electrons from cold cathode was concluded to be of photoemissive nature, enabling the production of high-intensity electron beams in any noble gas or in a mixture of a noble gas with molecular gases irrespective of cathode material.

  7. A Grounded Theory of the Development of Noble Youth Purpose

    ERIC Educational Resources Information Center

    Bronk, Kendall Cotton

    2012-01-01

    Having a noble purpose in life is an important component of positive youth development; however, little is known about how noble purposes develop over time. Therefore, using three waves of interviews over a 5-year period with 9 adolescents (N = 9) who demonstrated intense commitments to various noble purposes, the present study developed a…

  8. Catalytic combustion of actual low and medium heating value gases

    NASA Technical Reports Server (NTRS)

    Bulzan, D. L.

    1982-01-01

    Catalytic combustion of both low and medium heating value gases using actual coal derived gases obtained from operating gasifiers was demonstrated. A fixed bed gasifier with a complete product gas cleanup system was operated in an air blown mode to produce low heating value gas. A fluidized bed gasifier with a water quench product gas cleanup system was operated in both an air enriched and an oxygen blown mode to produce low and medium, heating value gas. Noble metal catalytic reactors were evaluated in 12 cm flow diameter test rigs on both low and medium heating value gases. Combustion efficiencies greater than 99.5% were obtained with all coal derived gaseous fuels. The NOx emissions ranged from 0.2 to 4 g NO2 kg fuel.

  9. Results from the XENON10 and the Race to Detect Dark Matter with Noble Liquids

    ScienceCinema

    Shutt, Tom [Case Western Reserve, Cleveland, Ohio, United States

    2016-07-12

    Detectors based on liquid noble gases have the potential to revolutionize the direct search for WIMP dark matter. The XENON10 experiment, of which I am a member, has recently announced the results from it's first data run and is now the leading WIMP search experiment. This and other experiments using xenon, argon and neon have the potential to rapidly move from the current kg-scale target mass to the ton scale and well beyond. This should allow a (nearly) definitive test or discovery of dark matter if it is in the form of weakly interacting massive particles.

  10. Apparatus for preparing a solution of a hyperpolarized noble gas for NMR and MRI analysis

    DOEpatents

    Pines, Alexander; Budinger, Thomas; Navon, Gil; Song, Yi-Qiao; Appelt, Stephan; Bifone, Angelo; Taylor, Rebecca; Goodson, Boyd; Seydoux, Roberto; Room, Toomas; Pietrass, Tanja

    2008-06-10

    The present invention relates generally to nuclear magnetic resonance (NMR) techniques for both spectroscopy and imaging. More particularly, the present invention relates to methods in which hyperpolarized noble gases (e.g., Xe and He) are used to enhance and improve NMR and MRI. Additionally, the hyperpolarized gas solutions of the invention are useful both in vitro and in vivo to study the dynamics or structure of a system. When used with biological systems, either in vivo or in vitro, it is within the scope of the invention to target the hyperpolarized gas and deliver it to specific regions within the system.

  11. Method for localized deposition of noble metal catalysts with control of morphology

    DOEpatents

    Ricco, Antonio J.; Manginell, Ronald P.; Huber, Robert J.

    1998-01-01

    A combustible gas sensor that uses a resistively heated, noble metal-coated, micromachined polycrystalline Si filament to calorimetrically detect the presence and concentration of combustible gases. A thin catalytic Pt film was deposited by CVD from the precursor Pt(acac).sub.2 onto microfilaments resistively heated to approximately 500 .degree. C.; Pt deposits only on the hot filament. The filaments tested to date are 2 .mu.m thick .times.10 .mu.m wide .times.100, 250, 500, or 1000 .mu.m-long polycrystalline Si; some are overcoated with a 0.25 .mu.m-thick protective CVD Si.sub.3 N.sub.4 layer.

  12. Theory of warm ionized gases: equation of state and kinetic Schottky anomaly.

    PubMed

    Capolupo, A; Giampaolo, S M; Illuminati, F

    2013-10-01

    Based on accurate Lennard-Jones-type interaction potentials, we derive a closed set of state equations for the description of warm atomic gases in the presence of ionization processes. The specific heat is predicted to exhibit peaks in correspondence to single and multiple ionizations. Such kinetic analog in atomic gases of the Schottky anomaly in solids is enhanced at intermediate and low atomic densities. The case of adiabatic compression of noble gases is analyzed in detail and the implications on sonoluminescence are discussed. In particular, the predicted plasma electron density in a sonoluminescent bubble turns out to be in good agreement with the value measured in recent experiments.

  13. The Colour of the Noble Metals.

    ERIC Educational Resources Information Center

    Poole, R. T.

    1983-01-01

    Examines the physical basis for colors of noble metals (copper, silver, gold) developed from energy conservation/quantum mechanical view of free electron photoabsorption. Describes production of absorption edges produced by change in density of occupied valence electron states in the d-band, which allows stronger absorption in the visible photon…

  14. MICROWAVE-ASSISTED SYNTHESIS OF NOBLE NANOSTRUCTURES

    EPA Science Inventory

    Microwave-assisted (MW) spontaneous reduction of noble metal salts, silver (Ag), gold (Au), platinum (Pt) and palladium (Pd) is reported using sugar solutions such as -D glucose, sucrose and maltose, etc. to generate nanomaterials. These MW-assisted reactions, conducted in aqueo...

  15. Natural Death and the Noble Savage.

    ERIC Educational Resources Information Center

    Walter, Tony

    1995-01-01

    The belief that dying and grieving are natural processes is widely held in modern bereavement care. Examines four assumption often made in this connection: (1) most primitive cultures deal with death in an accepting way; (2) this way is different than our own; (3) it is a good and noble way; and (4) traditional societies see death as natural. (JBJ)

  16. CONTROL ROD ALLOY CONTAINING NOBLE METAL ADDITIONS

    DOEpatents

    Anderson, W.K.; Ray, W.E.

    1960-05-01

    Silver-base alloys suitable for use in the fabrication of control rods for neutronic reactors are given. The alloy consists of from 0.5 wt.% to about 1.5 wt.% of a noble metal of platinum, ruthenium, rhodium, osmium, or palladium, up to 10 wt.% of cadmium, from 2 to 20 wt.% indium, the balance being silver.

  17. Trends in source gases

    NASA Technical Reports Server (NTRS)

    Ehhalt, D. H.; Fraser, P. J.; Albritton, D.; Cicerone, R. J.; Khalil, M. A. K.; Legrand, M.; Makide, Y.; Rowland, F. S.; Steele, L. P.; Zander, R.

    1989-01-01

    Source gases are defined as those gases that, by their breakdown, introduce into the stratosphere halogen, hydrogen, and nitrogen compounds that are important in stratospheric ozone destruction. Given here is an update of the existing concentration time series for chlorocarbons, nitrous oxide, and methane. Also reviewed is information on halogen containing species and the use of these data for establishing trends. Also reviewed is evidence on trends in trace gases that influence tropospheric chemistry and thus the tropospheric lifetimes of source gases, such as carbon dioxide, carbon monoxide, or nitrogen oxides. Much of the information is given in tabular form.

  18. The noble gas geochemistry of natural CO 2 gas reservoirs from the Colorado Plateau and Rocky Mountain provinces, USA

    NASA Astrophysics Data System (ADS)

    Gilfillan, Stuart M. V.; Ballentine, Chris J.; Holland, Greg; Blagburn, Dave; Lollar, Barbara Sherwood; Stevens, Scott; Schoell, Martin; Cassidy, Martin

    2008-02-01

    Identification of the source of CO 2 in natural reservoirs and development of physical models to account for the migration and interaction of this CO 2 with the groundwater is essential for developing a quantitative understanding of the long term storage potential of CO 2 in the subsurface. We present the results of 57 noble gas determinations in CO 2 rich fields (>82%) from three natural reservoirs to the east of the Colorado Plateau uplift province, USA (Bravo Dome, NM., Sheep Mountain, CO. and McCallum Dome, CO.), and from two reservoirs from within the uplift area (St. John's Dome, AZ., and McElmo Dome, CO.). We demonstrate that all fields have CO 2/ 3He ratios consistent with a dominantly magmatic source. The most recent volcanics in the province date from 8 to 10 ka and are associated with the Bravo Dome field. The oldest magmatic activity dates from 42 to 70 Ma and is associated with the McElmo Dome field, located in the tectonically stable centre of the Colorado Plateau: CO 2 can be stored within the subsurface on a millennia timescale. The manner and extent of contact of the CO 2 phase with the groundwater system is a critical parameter in using these systems as natural analogues for geological storage of anthropogenic CO 2. We show that coherent fractionation of groundwater 20Ne/ 36Ar with crustal radiogenic noble gases ( 4He, 21Ne, 40Ar) is explained by a two stage re-dissolution model: Stage 1: Magmatic CO 2 injection into the groundwater system strips dissolved air-derived noble gases (ASW) and accumulated crustal/radiogenic noble gas by CO 2/water phase partitioning. The CO 2 containing the groundwater stripped gases provides the first reservoir fluid charge. Subsequent charges of CO 2 provide no more ASW or crustal noble gases, and serve only to dilute the original ASW and crustal noble gas rich CO 2. Reservoir scale preservation of concentration gradients in ASW-derived noble gases thus provide CO 2 filling direction. This is seen in the Bravo Dome

  19. Temporal changes in noble gas compositions within the Aidlinsector ofThe Geysers geothermal system

    SciTech Connect

    Dobson, Patrick; Sonnenthal, Eric; Kennedy, Mack; van Soest,Thijs; Lewicki, Jennifer

    2006-05-03

    The use of nonreactive isotopic tracers coupled to a full thermal-hydrological reservoir simulation allows for an improved method of investigating how reservoir fluids contained within matrix and fractures contribute over time to fluids produced from geothermal systems. A combined field and modeling study has been initiated to evaluate the effects of injection, production, and fracture-matrix interaction on produced noble gas contents and isotopic ratios. Gas samples collected periodically from the Aidlin steam field at The Geysers, California, between 1997 and 2006 have been analyzed for their noble gas compositions, and reveal systematic shifts in abundance and isotopic ratios over time. Because of the low concentrations of helium dissolved in the injection waters, the injectate itself has little impact on the helium isotopic composition of the reservoir fluids over time. However, the injection process may lead to fracturing of reservoir rocks and an increase in diffusion-controlled variations in noble gas compositions, related to gases derived from fluids within the rock matrix.

  20. Ultrapure Gases - From the Production Plant to the Laboratory

    SciTech Connect

    Simgen, H.; Zuzel, G.

    2007-03-28

    Radioactive noble gas isotopes are a potential source of background in low-level physics experiments, since they are present in the atmosphere and also in widely used gases produced from the atmosphere. We have studied the 39Ar, 85Kr and 222Rn contamination of commercially available nitrogen using low background proportional counters and a rare gas mass spectrometer. It was found that air separation plants are very effective in removing traces of radioactive noble gases and that the available purity can be significantly higher than commercial specifications. On the other hand the gas handling processes which are necessary to deliver gases from the production plant to the customer are a possible source of re-contaminations and determine in most cases the achievable purity. By simulating these processes under realistic conditions we have establish together with the Italian company 'SOL group' a well controlled delivery path which can hold the purity. For the short-lived 222Rn the initial contamination is less critical, because it decays away. Instead the emanation rate of the cryogenic tank was found to determine the achievable purity, since it permanently delivers new 222Rn.

  1. Positron Impact Ionization in Noble Gas Atoms and Diatomic Molecules

    NASA Astrophysics Data System (ADS)

    Marler, J. P.

    2005-05-01

    Results are presented for absolute positronium formation and direct ionization by positron impact on Ne, Ar, Kr, Xe, N2, CO and O2 at energies from threshold up to 90 eV. The experiments use a high-resolution, trap-based positron beam and exploit the properties of positron orbits in a magnetic field [1]. Results for the noble gases are compared with theoretical predictions and with measurements obtained using a significantly different method [2]. Results for diatomic molecules are compared to other available measurements and theoretical calculations where available. There is generally good agreement between the experimental measurements, providing an important benchmark for theoretical calculations. Intriguing features in Ar and O2 will be discussed. [1] J.P. Sullivan, S.J. Gilbert, J.P. Marler, R.G. Greaves, S.J. Buckman and C.M. Surko., Phys. Rev. A. 66, 042708 (2002) [2] J.P. Marler, J.P. Sullivan and C.M. Surko, Phys. Rev. A (2005), in press.

  2. EXTERNAL PHOTOEVAPORATION OF THE SOLAR NEBULA: JUPITER's NOBLE GAS ENRICHMENTS

    SciTech Connect

    Monga, Nikhil; Desch, Steven

    2015-01-01

    We present a model explaining the elemental enrichments in Jupiter's atmosphere, particularly the noble gases Ar, Kr, and Xe. While He, Ne, and O are depleted, seven other elements show similar enrichments (∼3 times solar, relative to H). Being volatile, Ar is difficult to fractionate from H{sub 2}. We argue that external photoevaporation by far-ultraviolet (FUV) radiation from nearby massive stars removed H{sub 2}, He, and Ne from the solar nebula, but Ar and other species were retained because photoevaporation occurred at large heliocentric distances where temperatures were cold enough (≲ 30 K) to trap them in amorphous water ice. As the solar nebula lost H, it became relatively and uniformly enriched in other species. Our model improves on the similar model of Guillot and Hueso. We recognize that cold temperatures alone do not trap volatiles; continuous water vapor production is also necessary. We demonstrate that FUV fluxes that photoevaporated the disk generated sufficient water vapor in regions ≲ 30 K to trap gas-phase species in amorphous water ice in solar proportions. We find more efficient chemical fractionation in the outer disk: whereas the model of Guillot and Hueso predicts a factor of three enrichment when only <2% of the disk mass remains, we find the same enrichments when 30% of the disk mass remains. Finally, we predict the presence of ∼0.1 M {sub ⊕} of water vapor in the outer solar nebula and protoplanetary disks in H II regions.

  3. The contribution of hydrothermally altered ocean crust to the mantle halogen and noble gas cycles

    NASA Astrophysics Data System (ADS)

    Chavrit, Déborah; Burgess, Ray; Sumino, Hirochika; Teagle, Damon A. H.; Droop, Giles; Shimizu, Aya; Ballentine, Chris J.

    2016-06-01

    Recent studies suggest that seawater-derived noble gases and halogens are recycled into the deep mantle by the subduction of oceanic crust. To understand the processes controlling the availability of halogens and noble gases for subduction, we determined the noble gas elemental and isotopic ratios and halogen (Cl, Br, I) concentrations in 28 igneous samples from the altered oceanic crust (AOC) from 5 ODP sites in the Eastern and Western Pacific Ocean. Crushing followed by heating experiments enabled determination of noble gases and halogens in fluid inclusions and mineral phases respectively. Except for He and Ar, Ne, Kr and Xe isotopic ratios were all air-like suggesting that primary MORB signatures have been completely overprinted by air and/or seawater interaction. In contrast, 3He/4He ratios obtained by crushing indicate that a mantle helium component is still preserved, and 40Ar/36Ar values are affected by radiogenic decay in the mineral phases. The 130Xe/36Ar and 84Kr/36Ar ratios are respectively up to 15 times and 5 times higher than those of seawater and the highest ratios are found in samples affected by low temperature alteration (shallower than 800-900 m sub-basement). We consider three possible processes: (i) adsorption onto the clays present in the samples; (ii) fluid inclusions with a marine pore fluid composition; and (iii) fractionation of seawater through phase separation caused by boiling. Ninety percent of the Cl, Br and I were released during the heating experiments, showing that halogens are dominantly held in mineral phases prior to subduction. I/Cl ratios vary by 4 orders of magnitude, from 3 × 10-6 to 2 × 10-2. The mean Br/Cl ratio is 30% lower than in MORB and seawater. I/Cl ratios lower than MORB values are attributed to Cl-rich amphibole formation caused by hydrothermal alteration at depths greater than 800-900 m sub-basement together with different extents of I loss during low and high temperature alteration. At shallower depths, I

  4. Highly Fluorescent Noble Metal Quantum Dots

    PubMed Central

    Zheng, Jie; Nicovich, Philip R.; Dickson, Robert M.

    2009-01-01

    Highly fluorescent, water-soluble, few-atom noble metal quantum dots have been created that behave as multi-electron artificial atoms with discrete, size-tunable electronic transitions throughout the visible and near IR. These “molecular metals” exhibit highly polarizable transitions and scale in size according to the simple relation, Efermi/N1/3, predicted by the free electron model of metallic behavior. This simple scaling indicates that fluorescence arises from intraband transitions of free electrons and that these conduction electron transitions are the low number limit of the plasmon – the collective dipole oscillations occurring when a continuous density of states is reached. Providing the “missing link” between atomic and nanoparticle behavior in noble metals, these emissive, water-soluble Au nanoclusters open new opportunities for biological labels, energy transfer pairs, and light emitting sources in nanoscale optoelectronics. PMID:17105412

  5. Using noble gas ratios to determine the origin of ground ice

    NASA Astrophysics Data System (ADS)

    Utting, Nicholas; Lauriol, Bernard; Lacelle, Denis; Clark, Ian

    2016-01-01

    Argon, krypton and xenon have different solubilities in water, meaning their ratios in water are different from those in atmospheric air. This characteristic is used in a novel method to distinguish between ice bodies which originate from the compaction of snow (i.e. buried snow banks, glacial ice) vs. ice which forms from the freezing of groundwater (i.e. pingo ice). Ice which forms from the compaction of snow has gas ratios similar to atmospheric air, while ice which forms from the freezing of liquid water is expected to have gas ratios similar to air-equilibrated water. This analysis has been conducted using a spike dilution noble gas line with gas extraction conducted on-line. Samples were mixed with an aliquot of rare noble gases while being melted, then extracted gases are purified and cryogenically separated. Samples have been analysed from glacial ice, buried snow bank ice, intrusive ice, wedge ice, cave ice and two unknown ice bodies. Ice bodies which have formed from different processes have different gas ratios relative to their formation processes.

  6. Noble gas patterns in the atmospheres of Mars and Earth: A comparison via the SNC meteorites

    NASA Technical Reports Server (NTRS)

    Pepin, R. O.; Becker, R. H.

    1985-01-01

    Noble gas and nitrogen compositions in the glassy phase of the EETA 79001 shergottite correspond closely with Viking measurements. This direct evidence for the origin of the SNC meteorites on Mars, and for trapping of an unfractionated sample of Martian atmospheric gases in the 79001 glass, provides a reasonable basis for comparing the Martian and terrestrial atmospheres with more precision than that afforded by the Viking data set. Results are that, with one exception, elemental and isotopic compositions of nonradiogenic Martian noble gases are similar to those in the Earth's atmosphere; relatively small isotopic discrepancies in Kr and perhaps Xe may be attributable to different degrees of mass fractionation of a common parent reservoir. The anomaly is in Ar composition, where Martian Ar-36/AR-38 approx. 4 is strikingly lower than the values near 5.3 that characterize both the Earth and major meteoritic gas carriers. Although a primordial Martian ratio of 5.3 could in principle be altered by some planet specific process (e.g., cosmic ray spallation of surface materials) operating over geologic time, one has not been found that works.

  7. Noble gas isotopes and halogens in volatile-rich inclusions in diamonds

    NASA Technical Reports Server (NTRS)

    Burgess, Raymond; Turner, Grenville

    1994-01-01

    Application of the (40)Ar-(39)Ar method and noble gas studies to diamonds has increased our understanding of their age relationships to the host kimberlite or lamproite, and of the source and composition of volatile-rich fluids in the upper mantle. The properties of diamond (inert, high mechanical strength and low gas diffusivities) means they are especially useful samples for studying gases trapped deep within the earth (less than 150 km) as they are unlikely to have undergone loss or exchange of entrapped material since formation. Volatile-rich fluids (H2O-CO2) are important agents for metasomatic processes in the upper mantle, and the noble gases and halogens preferentially partition into this phase leading to a strong geochemical coherence between these groups of elements. The abundances of the halogens in the major reservoirs of the Earth shows a marked progression from chlorine, concentrated in the oceans, through to iodine which, through its affinity to organic material, is concentrated mainly in sediments. Abundances in the upper mantle are low. This is particularly true for iodine which is of special interest in view of its potential significance as an indicator of sediment recycling and by way of its link to (129)Xe amomalies in the mantle through the low extinct isotope (129)I. Extensions of the (40)Ar-(39)Ar technique enable measurements of halogens and other elements (K, Ca, Ba, U) by production of noble gas isotopes from these species during neutron irradiation. Samples analyzed in this way include 15 coated stones from an unknown source in Zaire, 3 boarts from the Jwaneng and 1 boart from the Orapa kimberlites, both in Botswana.

  8. Noble gas excimer scintillation following neutron capture in boron thin films

    SciTech Connect

    McComb, Jacob C.; Al-Sheikhly, Mohamad; Coplan, Michael A.; Thompson, Alan K.; Vest, Robert E.; Clark, Charles W.

    2014-04-14

    Far-ultraviolet scintillation signals have been measured in heavy noble gases (argon, krypton, xenon) following boron-neutron capture ({sup 10}B(n,α){sup 7}Li) in {sup 10}B thin films. The observed scintillation yields are comparable to the yields from some liquid and solid neutron scintillators. At noble gas pressures of 107 kPa, the number of photons produced per neutron absorbed following irradiation of a 1200 nm thick {sup 10}B film was 14 000 for xenon, 11 000 for krypton, and 6000 for argon. The absolute scintillation yields from the experimental configuration were calculated using data from (1) experimental irradiations, (2) thin-film characterizations, (3) photomultiplier tube calibrations, and (4) photon collection modeling. Both the boron films and the photomultiplier tube were characterized at the National Institute of Standards and Technology. Monte Carlo modeling of the reaction cell provided estimates of the photon collection efficiency and the transport behavior of {sup 10}B(n,α){sup 7}Li reaction products escaping the thin films. Scintillation yields increased with gas pressure due to increased ionization and excitation densities of the gases from the {sup 10}B(n,α){sup 7}Li reaction products, increased frequency of three-body, excimer-forming collisions, and reduced photon emission volumes (i.e., larger solid angle) at higher pressures. Yields decreased for thicker {sup 10}B thin films due to higher average energy loss of the {sup 10}B(n,α){sup 7}Li reaction products escaping the films. The relative standard uncertainties in the measurements were determined to lie between 14% and 16%. The observed scintillation signal demonstrates that noble gas excimer scintillation is promising for use in practical neutron detectors.

  9. Mantle and Crustal Sources of Carbon, Nitrogen, and Noble gases in Cascade-Range and Aleutian-Arc Volcanic gases

    USGS Publications Warehouse

    Symonds, Robert B.; Poreda, Robert J.; Evans, William C.; Janik, Cathy J.; Ritchie, Beatrice E.

    2003-01-01

    Here we report anhydrous chemical (CO2, H2S, N2, H2, CH4, O2, Ar, He, Ne) and isotopic (3He/4He, 40Ar/36Ar, δ13C of CO2, δ13C of CH4, δ15N) compositions of virtually airfree gas samples collected between 1994 and 1998 from 12 quiescent but potentially restless volcanoes in the Cascade Range and Aleutian Arc (CRAA). Sample sites include ≤173°C fumaroles and springs at Mount Shasta, Mount Hood, Mount St. Helens, Mount Rainier, Mount Baker, Augustine Volcano, Mount Griggs, Trident, Mount Mageik, Aniakchak Crater, Akutan, and Makushin. The chemical and isotopic data generally point to magmatic (CO2, Ar, He), shallow crustal sedimentary (hereafter, SCS) (CO2, N2, CH4), crustal (He), and meteoric (N2, Ar) sources of volatiles. CH4 clearly comes from SCS rocks in the subvolcanic systems because CH4 cannot survive the higher temperatures of deeper potential sources. Further evidence for a SCS source for CH4 as well as for non-mantle CO2 and non-meteoric N2 comes from isotopic data that show wide variations between volcanoes that are spatially very close and similar isotopic signatures from volcanoes from very disparate areas. Our results are in direct opposition to many recent studies on other volcanic arcs (Kita and others, 1993; Sano and Marty, 1995; Fischer and others, 1998), in that they point to a dearth of subducted components of CO2 and N2 in the CRAA discharges. Either the CRAA volcanoes are fundamentally different from volcanoes in other arcs or we need to reevaluate the significance of subducted C and N recycling in convergent-plate volcanoes.

  10. A new noble gas paleoclimate record in Texas — Basic assumptions revisited

    NASA Astrophysics Data System (ADS)

    Castro, Maria Clara; Hall, Chris Michael; Patriarche, Delphine; Goblet, Patrick; Ellis, Brian Robert

    2007-05-01

    A generally accepted basic principle in relation to the use of the noble gas thermometer in groundwater flow systems is that high-frequency noble gas climatic signals are lost due to the effect of dispersion. This loss of signal, combined with 14C dating issues, makes it only suited to identify major climatic events such as the Last Glacial Maximum (LGM). Consequently, the identification of significant noble gas temperature (NGT) cooling (≥ 5 °C) with respect to present time has systematically been associated with the occurrence of the LGM even when reasonable water age controls were unavailable. It has also become apparent at a number of studied sites that modern NGTs estimated through standard models [M. Stute, P. Schlosser, Principles and applications of the noble gas paleothermometer, in: P.K. Swart, K.C. Lohmann, J.A. McKenzie, S. Savin, (Eds), Climate change in continental isotopic records, Geophysical monograph 78, AGU (1993) 89-100.; W. Aeschbach-Hertig, F. Peeters, U. Beyerle, R. Kipfer, Paleotemperature reconstruction from noble gases in ground water taking into account equilibration with entrapped air, Nature 405(6790) (2000) 1040-1044.] are unable to reproduce ground temperatures at the interface with the unsaturated zone, a basic requirement for proper paleoclimate reconstruction through noble gases. Instead, a systematic bias to low NGTs in recharge areas is observed. The Carrizo aquifer, in which the LGM was previously identified [M. Stute, P. Schlosser, J.F. Clark, W.S. Broecker, Paleotemperatures in the Southwestern United States derived from noble gases in ground water, Science 256(5059) (1992) 1000-1001.] and which presents an NGT bias of over 4 °C, is an ideal setting to analyze and revise basic principles and assumptions in relation with the use of the noble gas thermometer. Here, we present a new noble gas data set (49 measurements) collected at 20 different locations in the Carrizo aquifer. This new data set together with previously

  11. Detection of Noble Gas Radionuclides from an Underground Nuclear Explosion During a CTBT On-Site Inspection

    NASA Astrophysics Data System (ADS)

    Carrigan, Charles R.; Sun, Yunwei

    2014-03-01

    The development of a technically sound approach to detecting the subsurface release of noble gas radionuclides is a critical component of the on-site inspection (OSI) protocol under the Comprehensive Nuclear Test Ban Treaty. In this context, we are investigating a variety of technical challenges that have a significant bearing on policy development and technical guidance regarding the detection of noble gases and the creation of a technically justifiable OSI concept of operation. The work focuses on optimizing the ability to capture radioactive noble gases subject to the constraints of possible OSI scenarios. This focus results from recognizing the difficulty of detecting gas releases in geologic environments—a lesson we learned previously from the non-proliferation experiment (NPE). Most of our evaluations of a sampling or transport issue necessarily involve computer simulations. This is partly due to the lack of OSI-relevant field data, such as that provided by the NPE, and partly a result of the ability of computer-based models to test a range of geologic and atmospheric scenarios far beyond what could ever be studied by field experiments, making this approach very highly cost effective. We review some highlights of the transport and sampling issues we have investigated and complete the discussion of these issues with a description of a preliminary design for subsurface sampling that addresses some of the sampling challenges discussed here.

  12. New applications of noble metal catalysts in hydrocracking

    SciTech Connect

    Mitchell, D.H.G.; Bertram, R.V.; Dencker, G.D.

    1995-09-01

    The paper explores how a noble metal hydrocracking catalyst functions stably in a hydrogen sulfide and ammonia environment and, in particular, how the physical positioning of the noble metal molecules affects catalyst performance. A commercial example, HC-28 catalyst in the Unicracking unit at Marathon Oil Refinery in Robinson, Illinois, demonstrates the success of the noble metal catalyst approach for naphtha production. In addition, a new Unicracking catalyst, HC-35, which uses a noble metal component to produce high-quality middle distillates, is introduced. The paper also shows how refiners may derive increased economic and operational benefits from their catalyst investment by using the latest developments in reactor internals design.

  13. Inert electrode containing metal oxides, copper and noble metal

    DOEpatents

    Ray, Siba P.; Woods, Robert W.; Dawless, Robert K.; Hosler, Robert B.

    2000-01-01

    A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

  14. Inert electrode containing metal oxides, copper and noble metal

    DOEpatents

    Ray, Siba P.; Woods, Robert W.; Dawless, Robert K.; Hosler, Robert B.

    2001-01-01

    A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

  15. Photochemistry of biogenic gases

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.

    1989-01-01

    The relationship between the biosphere and the atmosphere is examined, emphasizing the composition and photochemistry and chemistry of the troposphere and stratosphere. The reactions of oxygen, ozone, and hydroxyl are reviewed and the fate of the biogenic gases ammonia, methane, reduced sulfur species, reduced halogen species, carbon monoxide, nitric oxide, nitrous oxide, nitrogen, and carbon dioxide are described. A list is given of the concentration and sources of the various gases.

  16. Recycling of volatiles at subduction zones: Noble gas evidence from the Tabar-Lihir-Tanga-Feni arc of papua New Guinea

    NASA Technical Reports Server (NTRS)

    Farley, Kenneth; Mcinnes, Brent; Patterson, Desmond

    1994-01-01

    Convergent margin processes play an important but poorly understood role in the distribution of terrestrial volatile species. For example, subduction processes filter volatiles from the subducting package, thereby restricting their return to the mantle. In addition, once extracted from the downgoing slab, volatiles become an essential component in the petrogenesis of island arc magmas. The noble gases, with their systematic variation in physical properties and diversity of radiogenic isotopes, should carry a uniquely valuable record of these processes. However, thus far studies of noble gases in arc volcanics have achieved only limited success in this regard. Subduction-related lavas and geothermal fluids carry (3)He/(4)He ratios equal to or slightly lower than those found in the depleted upper mantle source of mid-ocean ridge basalts. Apparently slab-derived helium (which should have (3)He/(4)He much less than MORB) is extensively diluted by MORB-like helium from the mantle wedge, making it difficult to use helium as a tracer of convergent margin processes. Interpretation of the heavier noble gases (Ne-Ar-Kr-Xe) in arc lavas has also proven difficult, because the lavas carry low noble gas concentrations and hence are subject to pervasive atmospheric contamination. The low noble gas concentrations may be a consequence of degassing in the high level magma chambers characteristic of arc stratovolcanos. We have recently initiated a project to better constrain the behavior of volatiles in subduction zones through geochemical studies of the tectonically unusual volcanoes of the Tabar-Lihir-Tanga-Feni (TLTF) arc in the Bismarck Archipelago, Papua New Guinea.

  17. Photoelectron spectrometer for attosecond spectroscopy of liquids and gases

    NASA Astrophysics Data System (ADS)

    Jordan, I.; Huppert, M.; Brown, M. A.; van Bokhoven, J. A.; Wörner, H. J.

    2015-12-01

    A new apparatus for attosecond time-resolved photoelectron spectroscopy of liquids and gases is described. It combines a liquid microjet source with a magnetic-bottle photoelectron spectrometer and an actively stabilized attosecond beamline. The photoelectron spectrometer permits venting and pumping of the interaction chamber without affecting the low pressure in the flight tube. This pressure separation has been realized through a sliding skimmer plate, which effectively seals the flight tube in its closed position and functions as a differential pumping stage in its open position. A high-harmonic photon spectrometer, attached to the photoelectron spectrometer, exit port is used to acquire photon spectra for calibration purposes. Attosecond pulse trains have been used to record photoelectron spectra of noble gases, water in the gas and liquid states as well as solvated species. RABBIT scans demonstrate the attosecond resolution of this setup.

  18. Photoelectron spectrometer for attosecond spectroscopy of liquids and gases

    SciTech Connect

    Jordan, I.; Huppert, M.; Wörner, H. J.; Brown, M. A.; Bokhoven, J. A. van

    2015-12-15

    A new apparatus for attosecond time-resolved photoelectron spectroscopy of liquids and gases is described. It combines a liquid microjet source with a magnetic-bottle photoelectron spectrometer and an actively stabilized attosecond beamline. The photoelectron spectrometer permits venting and pumping of the interaction chamber without affecting the low pressure in the flight tube. This pressure separation has been realized through a sliding skimmer plate, which effectively seals the flight tube in its closed position and functions as a differential pumping stage in its open position. A high-harmonic photon spectrometer, attached to the photoelectron spectrometer, exit port is used to acquire photon spectra for calibration purposes. Attosecond pulse trains have been used to record photoelectron spectra of noble gases, water in the gas and liquid states as well as solvated species. RABBIT scans demonstrate the attosecond resolution of this setup.

  19. The unification of psychology: a noble quest.

    PubMed

    Calhoun, Lawrence G

    2004-12-01

    Henriques' effort to develop a unified theory for psychology represents a noble quest (this issue). Even if the quest fails, the effort itself may produce benefits for psychology. This article focuses first on some general comments on the unified theory, with some suggestions about elements that seem desirable in the theory and some elements that may benefit from further elaboration. A specific application to the area of posttraumatic growth suggests the theory is capable of providing a framework for understanding specific areas of human psychology. Finally, the potential future of the unified theory is considered with a focus on its potential as a "useful mass movement" in psychology.

  20. Generation of spectral clusters in a mixture of noble and Raman-active gases.

    PubMed

    Hosseini, Pooria; Abdolvand, Amir; St J Russell, Philip

    2016-12-01

    We report a novel scheme for the generation of dense clusters of Raman sidebands. The scheme uses a broadband-guiding hollow-core photonic crystal fiber (HC-PCF) filled with a mixture of H2, D2, and Xe for efficient interaction between the gas mixture and a green laser pump pulse (532 nm, 1 ns) of only 5 μJ of energy. This results in the generation from noise of more than 135 rovibrational Raman sidebands covering the visible spectral region with an average spacing of only 2.2 THz. Such a spectrally dense and compact fiber-based source is ideal for applications where closely spaced narrow-band laser lines with high spectral power density are required, such as in spectroscopy and sensing. When the HC-PCF is filled with a H2-D2 mixture, the Raman comb spans the spectral region from the deep UV (280 nm) to the near infrared (1000 nm).

  1. Release of Implanted Noble Gases from Metallic Glass Vitreloy During Pyrolysis

    NASA Technical Reports Server (NTRS)

    Meshik, A. P.; Hohenberg, C. M.; Burnett, D. S.; Woolum, D. S.

    2000-01-01

    Vitreloy, a metallic vitreous glass, was examined as a potential target material for the Genesis Mission solar wind collector. Stepped pyrolysis revealed that He and Ne implanted in Vitreloy were efficiently re-trapped during phase transitions.

  2. A generic biokinetic model for noble gases with application to radon

    SciTech Connect

    Leggett, Richard Wayne; Marsh, James; Gregoratto, Demetrio; Blanchardon, Eric

    2013-01-01

    The International Commission for Radiological Protection (ICRP) currently uses a dose conversion coefficient to calculate effective dose per unit exposure to radon and its progeny. The coefficient is derived by dividing the detriment associated with unit exposure to radon, as estimated from epidemiological studies, by the detriment per unit effective dose, as estimated mainly from atomic bomb survivor data and animal studies. In a recent statement the ICRP indicated that future guidance on exposure to radon and its progeny will be developed in the same way as guidance for any other radionuclide. That is, intake of radon and progeny will be limited on the basis of effective dose coefficients derived from biokinetic and dosimetric models. This paper proposes a biokinetic model for systemic (absorbed) radon for use in the calculation of dose coefficients for inhaled or ingested radon. The model is based largely on physical laws governing transfer of a non-reactive and soluble gas between materials. Model predictions are shown to be consistent with results of controlled studies of the fate of internally deposited radon in human subjects.

  3. Mass fractionation of noble gases in diffusion-limited hydrodynamic hydrogen escape.

    PubMed

    Zahnle, K; Kasting, J F; Pollack, J B

    1990-01-01

    Mass fractionation by hydrodynamic hydrogen escape is a promising mechanism for explaining the observed elemental and isotopic abundance patterns in terrestrial planet atmospheres. Previous work has considered only pure hydrogen winds. Here, the theory of mass fractionation by hydrogen escape is extended to atmospheres in which hydrogen is not the only major constituent. Analytical solutions are derived for cases in which all relevant atmospheric constituents escape; both analytical and numerical solutions are obtained for cases in which important heavy constituents are retained. In either case the fractionation patterns that result can differ significantly from those produced by pure hydrogen winds. Three applications of the theory are discussed: (1) The observed fractionation of terrestrial atmospheric neon with respect to mantle neon can be explained as a by-product of diffusion-limited hydrogen escape from a steam atmosphere toward the end of accretion. (2) The anomalously high Martian (SNC) 38Ar/36Ar ratio is attributed to hydrodynamic fractionation by a vigorously escaping, nearly pure hydrogen wind. (3) It is possible that the present high Martian D/H ratio was established during the same hydrodynamic escape phase that fractionated argon, but the predicted degree of D/H enrichment is sensitive to other, less well constrained parameters.

  4. Mass fractionation of noble gases in diffusion-limited hydrodynamic hydrogen escape

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin; Pollack, James B.; Kasting, James F.

    1990-01-01

    The theory of mass fractionation by hydrogen is presently extended to atmospheres in which hydrogen is not the major constituent. This theoretical framework is applied to three different cases. In the first, it is shown that the fractionation of terrestrial atmospheric neon with respect to mantle neon is explainable as a consequence of diffusion-limited hydrogen escape from a steam atmosphere toward the end of the accretion process. In the second, the anomalously high Ar-38/Ar-36 ratio of Mars is shown to be due to hydrodynamic fractionation by a vigorously escaping and very pure hydrogen wind. In the last case, it is speculated that the currently high Martian D/H ratio emerged during the hydrodynamic escape phase which fractionated Ar.

  5. Groundwater dynamics and arsenic mobilization in Bangladesh assessed using noble gases and tritium.

    PubMed

    Klump, Stephan; Kipfer, Rolf; Cirpka, Olaf A; Harvey, Charles F; Brennwald, Matthias S; Ashfaque, Khandaker N; Badruzzaman, Abu Borhan M; Hug, Stephan J; Imboden, Dieter M

    2006-01-01

    The contamination of groundwater by geogenic arsenic is the cause of major health problems in south and southeast Asia. Various hypotheses proposing that As is mobilized by the reduction of iron (oxy)hydroxides are now under discussion. One important and controversial question concerns the possibility that As contamination might be related to the extraction of groundwater for irrigation purposes. If As were mobilized by the inflow of re-infiltrating irrigation water rich in labile organic carbon, As-contaminated groundwater would have been recharged after the introduction of groundwater irrigation 20-40 years ago. We used environmental tracer data and conceptual groundwater flow and transport modeling to study the effects of groundwater pumping and to assess the role of reinfiltrated irrigation water in the mobilization of As. Both the tracer data and the model results suggest that pumping induces convergent groundwater flow to the depth of extraction and causes shallow, young groundwater to mix with deep, old groundwater. The As concentrations are greatest at a depth of 30 m where these two groundwater bodies come into contact and mix. There, within the mixing zone, groundwater age significantly exceeds 30 years, indicating that recharge of most of the contaminated water occurred before groundwater irrigation became established in Bangladesh. Hence, at least at our study site, the results call into question the validity of the hypothesis that re-infiltrated irrigation water is the direct cause of As mobilization; however, the tracer data suggest that, at our site, hydraulic changes due to groundwater extraction for irrigation might be related to the mobilization of As.

  6. Generation of spectral clusters in a mixture of noble and Raman-active gases

    NASA Astrophysics Data System (ADS)

    Hosseini, Pooria; Abdolvand, Amir; St. J. Russell, Philip

    2016-12-01

    We report a novel scheme for the generation of dense clusters of Raman sidebands. The scheme uses a broadband-guiding hollow-core photonic crystal fiber (HC-PCF) filled with a mixture of H2, D2, and Xe for efficient interaction between the gas mixture and a green laser pump pulse (532 nm, 1 ns) of only 5 uJ energy. This results in the generation from noise of more than 135 ro-vibrational Raman sidebands covering the visible spectral region with an average spacing of only 2 THz. Such a spectrally dense and compact fiber-based source is ideal for applications where closely spaced narrow-band laser lines with high spectral power density are required, such as in spectroscopy and sensing. When the HC-PCF is filled with a H2-D2 mixture the Raman comb spans the spectral region from the deep UV (280 nm) to the near infrared (1000 nm).

  7. A rigid sphere approach to positron elastic scattering by noble gases, molecular hydrogen, nitrogen and methane

    NASA Astrophysics Data System (ADS)

    Fedus, Kamil

    2016-12-01

    A simple potential model of a rigid sphere combined with an adiabatic dipole polarization ( r -4) is tested for positron-atom and positron-molecule elastic collisions. The numerical model, which is based on the analytical solution of radial Schrödinger equation for r -4 potential, depends solely upon the average dipole polarizability of the target and one adjustable parameter - the radius of a hard core. The validity of model is assessed by an extensive comparative study against numerous experimental cross-sections and theoretical phase-shifts of angular momentum partial waves for positrons scattered elastically by He, Ne, Ar, Kr, Xe, H2, N2 and CH4. In particular it is shown that this very simple approach can be used to model positron elastic collisions with targets characterized by moderate dipole polarizabilities (Ar, Kr, H2, N2) in good agreement with experiments for impact energies covering almost entire range from the positronium formation threshold down to the zero energy.

  8. Impact event at the Permian-Triassic boundary: evidence from extraterrestrial noble gases in fullerenes.

    PubMed

    Becker, L; Poreda, R J; Hunt, A G; Bunch, T E; Rampino, M

    2001-02-23

    The Permian-Triassic boundary (PTB) event, which occurred about 251.4 million years ago, is marked by the most severe mass extinction in the geologic record. Recent studies of some PTB sites indicate that the extinctions occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes (C60 to C200) from sediments at the PTB contain trapped helium and argon with isotope ratios similar to the planetary component of carbonaceous chondrites. These data imply that an impact event (asteroidal or cometary) accompanied the extinction, as was the case for the Cretaceous-Tertiary extinction event about 65 million years ago.

  9. Reconstructing the Paleo-Limnologic Evolution of Lake Bonney, Antarctica using Dissolved Noble Gases

    NASA Astrophysics Data System (ADS)

    Warrier, R. B.; Castro, M.; Hall, C. M.; Kenig, F. P.; Doran, P. T.

    2013-12-01

    The McMurdo Dry Valleys, situated on the western coast of the Ross Sea are the largest ice-free region in Antarctica. Lake Bonney (LB), located in western Taylor valley, one of the main east-west dry valleys, has two lobes, East Lake Bonney (ELB) and West Lake Bonney (WLB), which are separated by a narrow straight with a ~13 m deep sill. Because the evolution of LB is ultimately controlled by climate and because there are no reliable millennial-scale continental records of climate other than the Taylor Dome ice core in this region of Antarctica, a number of studies have reconstructed the paleolimnologic history of LB using diverse tools to try to reconstruct the history of the lake, and thus, the climate evolution in this area. However, many open questions remain with respect to the paleo-limnologic evolution of LB. To further place constraints on the evolution of LB, we analyzed 23 lake samples collected between 5 and ~40 m depth from both ELB and WLB for He and Ar concentrations as well as isotopic ratios. Preliminary results show that samples present He excesses up to two and three orders of magnitude with respect to air saturated water (ASW) in ELB and WLB, respectively. While He excesses generally increase with depth in WLB suggesting accumulation of 4He over time, a similar correlation with depth is not observed for ELB samples, indicating a more complex evolutionary history in this lobe. Measured R/Ra He isotopic ratios, where Ra is the atmospheric 3He/4He ratio, vary between 0.20-0.61 and 0.16-0.22 for ELB and WLB respectively, and indicate that observed He excesses are predominantly crustal in origin, with a small (<~5%) mantle contribution. In contrast, measured 40Ar/36Ar ratios indicate that Ar concentrations at all depths in ELB are atmospheric in origin while WLB samples below the sill indicate addition of excess 40Ar, likely of radiogenic origin. Preliminary estimates of water residence times based on measured He excesses and crustal production ratios from basement rocks point to maximum water ages of ~5 kyrs and ~500 kyrs for the deep waters of ELB and WLB, respectively. Similarly, a maximum residence time of ~500 kyrs was obtained for bottom waters of WLB assuming a crustal origin for the observed excess 40Ar. These preliminary age results are maximum estimations and assume that all He and Ar excesses are entirely of crustal origin. Our preliminary results indicate that the WLB waters have been isolated from the atmosphere for a much longer period of time than ELB waters and point to a very different evolution of both lobes. In addition, these maximum WLB ages obtained are much younger than previously thought (~1-5 Ma).

  10. Discharge stratification in noble gases as convergence of electron phase trajectories to attractors

    NASA Astrophysics Data System (ADS)

    Golubovskii, Yu.; Valin, S.; Pelyukhova, E.; Nekuchaev, V.; Sigeneger, F.

    2016-12-01

    A new dynamic method to analyse resonance effects in glow discharges is proposed as a supplement to fluid and kinetic approaches for the investigation of discharge stratification. The method is applicable to striations, which are caused by the nonlocal electron behaviour at lower pressure and current. It is based on the analysis of the electron phase trajectories in spatially periodic fields. Being quite intuitive and easier than the solution of the Boltzmann equation, this method gives a quantitative description of the main effects arising from the kinetic analysis, for example, the appearance of attractors of the phase trajectories. The dynamic theory eliminates the main difficulty of the kinetic theory associated with the large relaxation length of the electron energy distribution function in periodic fields and describes the integer and rational resonances that correspond to S-, P- and R-striations. As a result, the stratification of the discharge can be interpreted as the excitation of one of the spatial resonator modes of the positive column.

  11. Single Bubble Sonoluminescence (SBSL) in Water Containing Mixtures of Noble Gases Search for Segregation Effects

    NASA Astrophysics Data System (ADS)

    da Graca, Julio; Kojima, Haruo

    2003-11-01

    When large gradients in pressure and temperature are imposed in a gas mixture, constituent species are expected to segregate. We are continuing to search for evidence of such species segregation during the violent bubble collapse that occurs in SBSL. Light emission intensity (I), acoustic pressure amplitude (P_a), and the ambient bubble radius are measured for different mixing ratios of Ar and He. We have previously reported that the slope dI/dPa has a slight peak when the mixing ratio is 1:1 at room temperature. We interpreted the results as possible evidence of segregation [J. da Graça and H. Kojima, Phys. Rev. E 66, 066301 (2002)]. We have constructed an apparatus for studying the temperature dependence of SBSL between room temperature and 0^oC. We study the segregation effect as the water vapor pressure is reduced in the trapped bubble.

  12. DAVINCI: Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Garvin, James B.; Robertson, Brent; Johnson, Natasha M.; Amato, Michael J.; Thompson, Jessica; Goodloe, Colby; Everette, Dave

    2017-01-01

    DAVINCI is one of five Discovery-class missions selected by NASA in October 2015 for Phase A studies. Launching in November 2021 and arriving at Venus in June of 2023, DAVINCI would be the first U.S. entry probe to target Venus atmosphere in 45 years. DAVINCI is designed to study the chemical and isotopic composition of a complete cross-section of Venus atmosphere at a level of detail that has not been possible on earlier missions and to image the surface at optical wavelengths and process-relevant scales.

  13. Evaluation of a High Pressure Proportional Counter for the Detection of Radioactive Noble Gases

    DTIC Science & Technology

    1986-03-10

    109, and cobalt-57. ’K ’ 3 1 [,. %. . . . . . . . -Americium-241 has a half-life of 432.2 years and decays by alpha emission to neptunium - 237 ...Approximately 86 percent of these decays result in an excited state 59.537 keV above the ground state (17:430). Neptunium - 237 returns to the ground state by...to cause the resolu- tion to deteriorate to 5 percent (2.97 keY) (25: 237 ). For the anode wire used in this experiment (diameter = 0.0003" ± 2 percent

  14. Noble gases in the Murchison meteorite - Possible relics of s-process nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Srinivasan, B.; Anders, E.

    1978-01-01

    The Murchison carbonaceous chondrite contains a new type of xenon component, enriched by up to 50 percent in five of the nine stable xenon isotopes, mass numbers 128 to 132. This component is released at 1200 to 1600 C from a severely etched mineral fraction. Krypton shows a similar but smaller enrichment in the isotopes 80 and 82. Neon and helium released in the same interval also are quite anomalous, being highly enriched in the isotopes 22 and 3. These patterns are strongly suggestive of three nuclear processes believed to take place in red giants: the s process (neutron capture on a slow time scale), helium burning, and hydrogen shell burning. If this interpretation is correct, then primitive meteorites contain yet another kind of alien, presolar material: dust grains ejected from red giants.

  15. Predicted versus observed cosmic-ray-produced noble gases in lunar samples - Improved Kr production ratios

    NASA Technical Reports Server (NTRS)

    Regnier, S.; Hohenberg, C. M.; Marti, K.; Reedy, R. C.

    1979-01-01

    New sets of cross sections for the production of krypton isotopes from targets of Rb, Sr, Y, and Zr have been constructed primarily on the bases of experimental excitation functions for Kr production from Y. These cross sections were used to calculate galactic-cosmic-ray and solar-proton production rates for Kr isotopes in the moon. The paper reports spallation Kr data obtained from ilmenite separates of rocks 10017 and 10047. Production rates and isotopic ratios for cosmogenic Kr observed in ten well-documented lunar samples and in ilmenite separates and bulk samples from several lunar rocks with long but unknown irradiation histories were compared with predicted rates and ratios. The agreements were generally quite good.

  16. Trapping Planetary Noble Gases During the Fischer-Tropsch-Type Synthesis of Organic Materials

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A.; Johnson, N. M.; Meshik, A.

    2010-01-01

    When hydrogen, nitrogen and CO arc exposed to amorphous iron silicate surfaces at temperatures between 500 - 900K, a carbonaceous coating forms via Fischer-Tropsch type reactions!, Under normal circumstances such a catalytic coating would impede or stop further reaction. However, we find that this coating is a better catalyst than the amorphous iron silicates that initiate these rcactions:u . The formation of a self-perpetuating catalytic coating on grain surfaces could explain the rich deposits of macromolecular carbon found in primitive meteorites and would imply that protostellar nebulae should be rich in organic materiaL Many more experiments are needed to understand this chemical system and its application to protostellar nebulae.

  17. Molecular complexes of organometallic molecules with noble gases: the rotational spectrum of dimethylsilane-argon.

    PubMed

    Ottaviani, Paolo; Melandri, Sonia; Caminati, Walther; Banser, Deike; Schnell, Melanie; Grabow, Jens-Uwe

    2004-11-12

    The rotational spectrum of the molecular complex dimethylsilane-argon was investigated by free-jet absorption millimeter-wave and molecular-beam Fourier transform spectroscopy. The absolute energy minimum corresponds to a conformation in which the argon atom lies in the plane of symmetry of dimethylsilane, perpendicular to the C-Si-C plane. The distance of Ar atom is tilted 14 degrees away from the Si atom. The zero-point dissociation energy was estimated from the centrifugal distortion constant D(J) to be 2.2 kJ mol(-1). Small splitting, due to tunneling of the Ar atom and internal rotation of the two methyl groups, was observed, measured, and used to determine the potential energy surface for these motions.

  18. Noble gas storage and delivery system for ion propulsion

    NASA Technical Reports Server (NTRS)

    Back, Dwight Douglas (Inventor); Ramos, Charlie (Inventor)

    2001-01-01

    A method and system for storing and delivering a noble gas for an ion propulsion system where an adsorbent bearing a noble gas is heated within a storage vessel to desorb the noble gas which is then flowed through a pressure reduction device to a thruster assembly. The pressure and flow is controlled using a flow restrictor and low wattage heater which heats an adsorbent bed containing the noble gas propellant at low pressures. Flow rates of 5-60 sccm can be controlled to within about 0.5% or less and the required input power is generally less than 50 W. This noble gas storage and delivery system and method can be used for earth orbit satellites, and lunar or planetary space missions.

  19. Strongly correlated Bose gases

    NASA Astrophysics Data System (ADS)

    Chevy, F.; Salomon, C.

    2016-10-01

    The strongly interacting Bose gas is one of the most fundamental paradigms of quantum many-body physics and the subject of many experimental and theoretical investigations. We review recent progress on strongly correlated Bose gases, starting with a description of beyond mean-field corrections. We show that the Efimov effect leads to non universal phenomena and to a metastability of the low temperature Bose gas through three-body recombination to deeply bound molecular states. We outline differences and similarities with ultracold Fermi gases, discuss recent experiments on the unitary Bose gas, and finally present a few perspectives for future research.

  20. Looking for a correlation between terrestrial age and noble gas record of H chondrites

    NASA Astrophysics Data System (ADS)

    Loeken, Th.; Schultz, L.

    1994-07-01

    On the basis of statistically significant concentration differences of some trace elements, it has been suggested that H chondrites found in Antarctica and Modern Falls represent members of different extraterrestrial populations with different thermal histories. It was also concluded that H chondrites found in Victoria Land (Allan Hills) differ chemically from those found in Queen Maud Land (Yamato Mountains), an effect that could be based on the different terrestrial age distribution of both groups. This would imply a change of the meteoroid flux hitting the Earth on a timescale that is comparable to typical terrestrial ages of Antarctic chondrites. A comparison of the noble gas record of H chondrites from the Allan Hills icefields and Modern Fall shows that the distributions of cosmic-ray exposure ages and the concentrations of radiogenic He-4 and Ar-40 are very similar. In an earlier paper we compared the noble gas measurements of 20 Yamato H contents with meteorites from the Allan Hills region and Modern Falls. Similar distributions were found. The distribution of cosmic-ray exposure ages and radiogenic He-4 and Ar-40 gas contents as a function of the terrestrial age is investigated in these chondrites. The distribution shows the well-known 7-Ma-cluster indicating that about 40% of the H chondrites were excavated from their parent body in a single event. Both populations, Antarctic Meteorites and Modern Falls, exhibit the same characteristic feature: a major meteoroid-producing event about 7 Ma. This indicates that one H-group population delivers H chondrites to Antarctica and the rest of the world. Cosmic-ray exposure ages and thermal-history indicaters like radiogenic noble gases show no evidence of a change in the H chondrite meteoroid population during the last 200,000 years.

  1. Noble Metal Nanoparticles Applications in Cancer

    PubMed Central

    Conde, João; Doria, Gonçalo; Baptista, Pedro

    2012-01-01

    Nanotechnology has prompted new and improved materials for biomedical applications with particular emphasis in therapy and diagnostics. Special interest has been directed at providing enhanced molecular therapeutics for cancer, where conventional approaches do not effectively differentiate between cancerous and normal cells; that is, they lack specificity. This normally causes systemic toxicity and severe and adverse side effects with concomitant loss of quality of life. Because of their small size, nanoparticles can readily interact with biomolecules both at surface and inside cells, yielding better signals and target specificity for diagnostics and therapeutics. This way, a variety of nanoparticles with the possibility of diversified modification with biomolecules have been investigated for biomedical applications including their use in highly sensitive imaging assays, thermal ablation, and radiotherapy enhancement as well as drug and gene delivery and silencing. Here, we review the available noble metal nanoparticles for cancer therapy, with particular focus on those already being translated into clinical settings. PMID:22007307

  2. Noble gas isotopes in mineral springs and wells within the Cascadia forearc, Washington, Oregon, and California

    USGS Publications Warehouse

    McCrory, Patricia A.; Constantz, James E.; Hunt, Andrew G.

    2017-01-31

    IntroductionThis U.S. Geological Survey report presents laboratory analyses along with field notes for an exploratory study to document the relative abundance of noble gases in mineral springs and water wells within the Cascadia forearc of Washington, Oregon, and California (fig. 1). This report describes 14 samples collected in 2014 and 2015 and complements a previous report that describes 9 samples collected in 2012 and 2013 (McCrory and others, 2014b). Estimates of the depth to the underlying Juan de Fuca oceanic plate beneath sample sites are derived from the McCrory and others (2012) slab model. Some of the springs have been previously sampled for chemical analyses (Mariner and others, 2006), but none of the springs or wells currently has publicly available noble gas data. The helium and neon isotope values and ratios presented below are used to determine the sources and mixing history of these mineral and well waters (for example, McCrory and others, 2016).

  3. Modeling nuclear and electronic recoils in noble gas detectors with NEST

    NASA Astrophysics Data System (ADS)

    Mock, Jeremy; NEST Collaboration

    2015-10-01

    Noble gases such as xenon and argon are used as targets in single and dual phased rare event detectors like those used in the search for dark matter. Such experiments require an understanding of the behavior of the target material in the presence of low-energy ionizing radiation. This understanding allows an exploration of detector effects such as threshold, energy and position reconstruction, and pulse shape discrimination. The Noble Element Simulation Technique (NEST) package is a comprehensive code base that models the scintillation and ionization yields from liquid and gaseous xenon and argon in the energy regimes of interest to many types of experiments, like dark matter and neutrino detectors. NEST is built on multiple physics models, which are constrained by available data for both electronic and nuclear recoils. A substantial body of data exists in the literature, and we are reaching an era in which sub-keV yields can be explored experimentally. Here we present a new global analysis of all available nuclear recoil data, and the latest updates to the electronic recoil model, in light of recent low-energy measurements and an improved understanding of detector systematics.

  4. Development of Laser-Polarized Noble Gas Magnetic Resonance Imaging (MRI) Technology

    NASA Technical Reports Server (NTRS)

    Walsworth, Ronald L.

    2004-01-01

    We are developing technology for laser-polarized noble gas nuclear magnetic resonance (NMR), with the aim of enabling it as a novel biomedical imaging tool for ground-based and eventually space-based application. This emerging multidisciplinary technology enables high-resolution gas-space magnetic resonance imaging (MRI)-e.g., of lung ventilation, perfusion, and gas-exchange. In addition, laser-polarized noble gases (3He and 1BXe) do not require a large magnetic field for sensitive NMR detection, opening the door to practical MRI with novel, open-access magnet designs at very low magnetic fields (and hence in confined spaces). We are pursuing two specific aims in this technology development program. The first aim is to develop an open-access, low-field (less than 0.01 T) instrument for MRI studies of human gas inhalation as a function of subject orientation, and the second aim is to develop functional imaging of the lung using laser-polarized He-3 and Xe-129.

  5. Hyperpolarized noble gas magnetic resonance imaging of the animal lung: Approaches and applications

    NASA Astrophysics Data System (ADS)

    Santyr, Giles E.; Lam, Wilfred W.; Parra-Robles, Juan M.; Taves, Timothy M.; Ouriadov, Alexei V.

    2009-05-01

    Hyperpolarized noble gas (HNG) magnetic resonance (MR) imaging is a very promising noninvasive tool for the investigation of animal models of lung disease, particularly to follow longitudinal changes in lung function and anatomy without the accumulated radiation dose associated with x rays. The two most common noble gases for this purpose are H3e (helium 3) and X129e (xenon 129), the latter providing a cost-effective approach for clinical applications. Hyperpolarization is typically achieved using spin-exchange optical pumping techniques resulting in ˜10 000-fold improvement in available magnetization compared to conventional Boltzmann polarizations. This substantial increase in polarization allows high spatial resolution (<1 mm) single-slice images of the lung to be obtained with excellent temporal resolution (<1 s). Complete three-dimensional images of the lungs with 1 mm slice thickness can be obtained within reasonable breath-hold intervals (<20 s). This article provides an overview of the current methods used in HNG MR imaging with an emphasis on ventilation studies in animals. Special MR hardware and software considerations are described in order to use the strong but nonrecoverable magnetization as efficiently as possible and avoid depolarization primarily by molecular oxygen. Several applications of HNG MR imaging are presented, including measurement of gross lung anatomy (e.g., airway diameters), microscopic anatomy (e.g., apparent diffusion coefficient), and a variety of functional parameters including dynamic ventilation, alveolar oxygen partial pressure, and xenon diffusing capacity.

  6. Atomic Layer Deposition Route To Tailor Nanoalloys of Noble and Non-noble Metals.

    PubMed

    Ramachandran, Ranjith K; Dendooven, Jolien; Filez, Matthias; Galvita, Vladimir V; Poelman, Hilde; Solano, Eduardo; Minjauw, Matthias M; Devloo-Casier, Kilian; Fonda, Emiliano; Hermida-Merino, Daniel; Bras, Wim; Marin, Guy B; Detavernier, Christophe

    2016-09-27

    Since their early discovery, bimetallic nanoparticles have revolutionized various fields, including nanomagnetism and optics as well as heterogeneous catalysis. Knowledge buildup in the past decades has witnessed that the nanoparticle size and composition strongly impact the nanoparticle's properties and performance. Yet, conventional synthesis strategies lack proper control over the nanoparticle morphology and composition. Recently, atomically precise synthesis of bimetallic nanoparticles has been achieved by atomic layer deposition (ALD), alleviating particle size and compositional nonuniformities. However, this bimetal ALD strategy applies to noble metals only, a small niche within the extensive class of bimetallic alloys. We report an ALD-based approach for the tailored synthesis of bimetallic nanoparticles containing both noble and non-noble metals, here exemplified for Pt-In. First, a Pt/In2O3 bilayer is deposited by ALD, yielding precisely defined Pt-In nanoparticles after high-temperature H2 reduction. The nanoparticles' In content can be accurately controlled over the whole compositional range, and the particle size can be tuned from micrometers down to the nanometer scale. The size and compositional flexibility provided by this ALD-approach will trigger the fabrication of fully tailored bimetallic nanomaterials, including superior nanocatalysts.

  7. Spectral anomalies of the light-induced drift of rubidium atoms caused by the velocity dependence of transport collision frequencies

    NASA Astrophysics Data System (ADS)

    Parkhomenko, A. I.; Shalagin, A. M.

    2014-02-01

    The spectral features of the light-induced drift (LID) velocity for rubidium atoms (85Rb and 87Rb) in an argon buffer medium and in binary buffer mixtures of noble gases (Ne + Ar, Ne + Kr, Ne + Xe, He + Ar, He + Kr, and He + Xe) have been investigated theoretically. A strong temperature dependence of the spectral shape of the LID signal for Rb atoms in an Ar atmosphere is predicted in the temperature range 450 K < T < 800 K. It is shown that the anomalous LID of Rb atoms in binary buffer mixtures of noble gases can be observed at almost any temperature (including the room one) depending on the fractions of neon or helium in these mixtures. The results obtained enable a highly accurate testing of the interatomic interaction potentials used to calculate the drift velocity for anomalous LID in LID experiments.

  8. Mineralogy and noble gas isotopes of micrometeorites collected from Antarctic snow

    NASA Astrophysics Data System (ADS)

    Okazaki, Ryuji; Noguchi, Takaaki; Tsujimoto, Shin-ichi; Tobimatsu, Yu; Nakamura, Tomoki; Ebihara, Mitsuru; Itoh, Shoichi; Nagahara, Hiroko; Tachibana, Shogo; Terada, Kentaro; Yabuta, Hikaru

    2015-06-01

    We have investigated seven micrometeorites (MMs) from Antarctic snow collected in 2003 and 2010 by means of electron microscopy, X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy (TEM) observation, and noble-gas isotope analysis. Isotopic ratios of He and Ne indicate that the noble gases in these MMs are mostly of solar wind (SW). Based on the release patterns of SW 4He, which should reflect the degree of heating during atmospheric entry, the seven MMs were classified into three types including two least heated, three moderately heated, and two severely heated MMs. The heating degrees are well correlated to their mineralogical features determined by TEM observation. One of the least heated MMs is composed of phyllosilicates, whereas the other consists of anhydrous minerals within which solar flare tracks were observed. The two severely heated MMs show clear evidence of atmospheric heating such as partial melt of the uppermost surface layer in one and abundant patches of dendritic magnetite and Si-rich glass within an olivine grain in the other. It is noteworthy that a moderately heated MM composed of a single crystal of olivine has a 3He/4He ratio of 8.44 × 10-4, which is higher than the SW value of 4.64 × 10-4, but does not show a cosmogenic 21Ne signature such as 20Ne/21Ne/22Ne = 12.83/0.0284/1. The isotopic compositions of He and Ne in this sample cannot be explained by mixing of a galactic cosmic ray (GCR)-produced component and SW gases. The high 3He/4He ratio without cosmogenic 21Ne signature likely indicates the presence of a 3He-enriched component derived from solar energetic particles.

  9. Laser microprobe analyses of noble gas isotopes and halogens in fluid inclusions: Analyses of microstandards and synthetic inclusions in quartz

    USGS Publications Warehouse

    Böhlke, J.K.; Irwin, J.J.

    1992-01-01

    Ar, Kr, Xe, Cl, Br, I, and K abundances and isotopic compositions have been measured in microscopic fluid inclusions in minerals by noble gas mass spectrometry following neutron irradiation and laser extraction. The laser microprobe noble gas mass spectrometric (LMNGMS) technique was quantified by use of microstandards, including air-filled capillary tubes, synthetic basalt glass grains, standard hornblende grains, and synthetic fluid inclusions in quartz. Common natural concentrations of halogens (Cl, Br, and I) and noble gases (Ar and Kr) in trapped groundwaters and hydrothermal fluids can be analyzed simultaneously by LMNGMS in as little as 10-11 L of inclusion fluid, with accuracy and precision to within 5-10% for element and isotope ratios. Multicomponent element and isotope correlations indicate contaminants or persistent reservoirs of excess Xe and/or unfractionated air in some synthetic and natural fluid inclusion samples. LMNGMS analyses of natural fluid inclusions using the methods and calibrations reported here may be used to obtain unique information on sources of fluids, sources of fluid salinity, mixing, boiling (or unmixing), and water-rock interactions in ancient fluid flow systems. ?? 1992.

  10. Kinetic Theory of Gases

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The theory, developed in the nineteenth century, notably by Rudolf Clausius (1822-88) and James Clerk Maxwell (1831-79), that the properties of a gas (temperature, pressure, etc) could be described in terms of the motions (and kinetic energy) of the molecules comprising the gases. The theory has wide implications in astrophysics. In particular, the perfect gas law, which relates the pressure, vol...

  11. Sudden releases of gases

    NASA Astrophysics Data System (ADS)

    Chaloupecká, Hana; Jaňour, Zbyněk; Jurčáková, Klára; Kukačka, Libor; Nosek, Štěpán

    2014-03-01

    Conurbations all over the world have enlarged for numberless years. The accidental or intentional releases of gases become more frequent. Therefore, these crises situations have to be studied. The aim of this paper is to describe experiments examining these processes that were carried out in the laboratory of Environmental Aerodynamics of the Institute of Thermomechanics AS CR in Nový Knín. Results show huge puff variability from replica to replica.

  12. Toxic gases from fires.

    PubMed

    Terrill, J B; Montgomery, R R; Reinhardt, C F

    1978-06-23

    The major lethal factors in uncontrolled fires are toxic gases, heat, and oxygen deficiency. The predominant toxic gas is carbon monoxide, which is readily generated from the combusion of wood and other cellulosic materials. Increasing use of a variety of synthetic polymers has stimulated interest in screening tests to evaluated the toxicity of polymeric materials when thermally decomposed. As yet, this country lacks a standardized fire toxicity test protocol.

  13. Mitigation of hydrogen by oxidation using nitrous oxide and noble metal catalysts

    SciTech Connect

    Britton, M.D.

    1995-01-19

    This test studied the ability of a blend of nuclear-grade, noble-metal catalysts to catalyze a hydrogen/nitrous oxide reaction in an effort to mitigate a potential hydrogen (H{sub 2}) gas buildup in the Hanford Site Grout Disposal Facility. For gases having H{sub 2} and a stoichiometric excess of either nitrous oxide or oxygen, the catalyst blend can effectively catalyze the H{sub 2} oxidation reaction at a rate exceeding 380 {mu}moles of H{sub 2} per hour per gram of catalyst ({mu}mol/h/g) and leave the gas with less than a 0.15 residual H{sub 2} Concentration. This holds true in gases with up to 2.25% water vapor and 0.1% methane. This should also hold true for gases with up to 0.1% carbon monoxide (CO) but only until the catalyst is exposed to enough CO to block the catalytic sites and stop the reaction. Gases with ammonia up to 1% may be slightly inhibited but can have reaction rates greater than 250 {mu}mol/h/g with less than a 0.20% residual H{sub 2} concentration. The mechanism for CO poisoning of the catalyst is the chemisorption of CO to the active catalyst sites. The CO sorption capacity (SC) of the catalyst is the total amount of CO that the catalyst will chemisorb. The average SC for virgin catalyst was determined to be 19.3 {plus_minus} 2.0 {mu}moles of CO chemisorbed to each gram of catalyst ({mu}mol/g). The average SC for catalyst regenerated with air was 17.3 {plus_minus} 1.9 {mu}mol/g.

  14. Heterogeneous upper mantle Ne, Ar and Xe isotopic compositions and a possible Dupal noble gas signature recorded in basalts from the Southwest Indian Ridge

    NASA Astrophysics Data System (ADS)

    Parai, R.; Mukhopadhyay, S.; Standish, J. J.

    2012-12-01

    mantle domain. Our observations require that the sampled mantle domain either is very ancient (>4.45 Ga) or has been metasomatized by subduction zone fluids carrying recycled atmospheric Ar and Xe. However, our Xe isotopic measurements indicate that differences between MORB and ocean island basalt (OIB) source noble gas compositions cannot be explained by recycling of atmospheric noble gases alone. Instead, a relatively undegassed mantle reservoir is required to account for OIB noble gases. The SWIR data demonstrate that the reservoir supplying primordial noble gases to mantle plumes differentiated from the MORB source early in Earth history, and the two reservoirs have not been homogenized over 4.45 Ga of mantle convection.

  15. A Philippinite with an Unusually Large Bubble: Gas Pressure and Noble Gas Composition

    NASA Astrophysics Data System (ADS)

    Matsuda, J.; Maruoka, T.; Pinti, D. L.; Koeberl, C.

    1995-09-01

    Bubbles are common in tektites, but usually their sizes range up to only a few mm. They are most abundant in Muong Nong-type tektites. The gases contained in these bubbles are of terrestrial atmospheric composition, with pressures below 1 atm (e.g., [1]). The abundances of light noble gases (He, Ne) are controlled by diffusion from the atmosphere [2], and noble gases dissolved in tektite glass indicate that the glass solidified at atmospheric pressures equivalent to about 40 km altitude [3]. Large bubbles in splash-form tektites are rather rare. Thus, the finding that a philippinite (size: 6.0 x 4.5 cm; weight: 199.6 g) contains an unusually large bubble justified a detailed study. The volume of the bubble, which was confirmed by X-ray photography, was estimated at 5.4 cm^3, by comparing the density of this tektite (2.288 g/cm^3) to that of normal philippinites (2.438 g/cm^3). A device was specifically constructed for crushing the present sample under vacuum. The 10x10 cm cylindrical device has a piston that allows to gently crush the sample by turning a handle. Various disk spacers can be used to adjust the inner height to that of the sample. The device is made of stainless steel, yielding a low noble gas blank. The crushing device is connected to a purification line and a noble gas sector-type mass spectrometer (VG 5400) [4]. Before crushing, the complete tektite was wrapped in aluminum foil. A first crushing attempt, using stainless steel disk spacers, failed and resulted in damage to the steel spacers, indicating a high strength of the tektite. Using iron disk spacers resulted in an ambient pressure increase (probably due to hydrogen from the Fe) in the sample chamber. However, the noble gas blanks were negligible. The background pressure, at 2 x 10-4 Torr, increased to 3 x 10-4 Torr when the sample was crushed. From the volume of the crushing device and that of the bubble in the tektite, the total gas pressure in the bubble was estimated at about 1 x 10-4 atm

  16. Thermal conductivity of graphene nanoribbons in noble gaseous environments

    SciTech Connect

    Zhong, Wei-Rong Xu, Zhi-Cheng; Zheng, Dong-Qin; Ai, Bao-Quan

    2014-02-24

    We investigate the thermal conductivity of suspended graphene nanoribbons in noble gaseous environments using molecular dynamics simulations. It is reported that the thermal conductivity of perfect graphene nanoribbons decreases with the gaseous pressure. The decreasing is more obvious for the noble gas with large atomic number. However, the gaseous pressure cannot change the thermal conductivity of defective graphene nanoribbons apparently. The phonon spectra of graphene nanoribbons are also provided to give corresponding supports.

  17. High Voltage in Noble Liquids for High Energy Physics

    SciTech Connect

    Rebel, B.; Bernard, E.; Faham, C. H.; Ito, T. M.; Lundberg, B.; Messina, M.; Monrabal, F.; Pereverzev, S. P.; Resnati, F.; Rowson, P. C.; Soderberg, M.; Strauss, T.; Tomas, A.; Va'vra, J.; Wang, H.

    2014-08-22

    A workshop was held at Fermilab November 8-9, 2013 to discuss the challenges of using high voltage in noble liquids. The participants spanned the fields of neutrino, dark matter, and electric dipole moment physics. All presentations at the workshop were made in plenary sessions. This document summarizes the experiences and lessons learned from experiments in these fields at developing high voltage systems in noble liquids.

  18. Isotopic studies of rare gases in terrestrial samples and natural nucleosynthesis

    SciTech Connect

    Not Available

    1991-05-01

    This project is concerned with research in rare gas mass spectrometry. Using a two-pronged attack, we study fluids using a system (RARGA) designed for fluid analysis in bulk which is sometimes deployed in the field and a laser microprobe mass spectrometer for fluid inclusion studies. In 1991 the RARGA project continued monitoring helium isotope variations associated with renewed seismic activity in Long Valley Caldera and expanded our geothermal data base to include Lassen National Park. An important objective, continuing in 1992, is to understand better the reasons for somewhat elevated {sup 3}He/{sup 4}He ratios in regions where there is no contemporary volcanism which could produce the effect by addition of mantle helium. To this end, 1991 saw continued efforts to understand variations in composition between fluids and associated reservoir rocks and extended the data base to include fluids from the Gulf of Mexico. Our DOE work in calibrating a sensitive laser microprobe mass spectrometer for noble gases in fluid inclusions continues with successful returns particularly in calibrating neutron irradiated samples for tracing halogen ratios. In connection with observations of neutron-produced noble gas nuclides in granites, we have begun comparing measurements with calculations for both thermal and epithermal neutrons. We submitted a third paper on noble gases in diamonds, concentrating on observed effects of {sup 4}He, {sup 3}He, and fission xenon implantation from nuclear processes in adjacent material in the matrix rock. 16 refs., 1 tab.

  19. Isotopic studies of rare gases in terrestrial samples and natural nucleosynthesis. Progress report

    SciTech Connect

    Not Available

    1991-05-01

    This project is concerned with research in rare gas mass spectrometry. Using a two-pronged attack, we study fluids using a system (RARGA) designed for fluid analysis in bulk which is sometimes deployed in the field and a laser microprobe mass spectrometer for fluid inclusion studies. In 1991 the RARGA project continued monitoring helium isotope variations associated with renewed seismic activity in Long Valley Caldera and expanded our geothermal data base to include Lassen National Park. An important objective, continuing in 1992, is to understand better the reasons for somewhat elevated {sup 3}He/{sup 4}He ratios in regions where there is no contemporary volcanism which could produce the effect by addition of mantle helium. To this end, 1991 saw continued efforts to understand variations in composition between fluids and associated reservoir rocks and extended the data base to include fluids from the Gulf of Mexico. Our DOE work in calibrating a sensitive laser microprobe mass spectrometer for noble gases in fluid inclusions continues with successful returns particularly in calibrating neutron irradiated samples for tracing halogen ratios. In connection with observations of neutron-produced noble gas nuclides in granites, we have begun comparing measurements with calculations for both thermal and epithermal neutrons. We submitted a third paper on noble gases in diamonds, concentrating on observed effects of {sup 4}He, {sup 3}He, and fission xenon implantation from nuclear processes in adjacent material in the matrix rock. 16 refs., 1 tab.

  20. U.S. Geological Survey Noble Gas Laboratory’s standard operating procedures for the measurement of dissolved gas in water samples

    USGS Publications Warehouse

    Hunt, Andrew G.

    2015-08-12

    This report addresses the standard operating procedures used by the U.S. Geological Survey’s Noble Gas Laboratory in Denver, Colorado, U.S.A., for the measurement of dissolved gases (methane, nitrogen, oxygen, and carbon dioxide) and noble gas isotopes (helium-3, helium-4, neon-20, neon-21, neon-22, argon-36, argon-38, argon-40, kryton-84, krypton-86, xenon-103, and xenon-132) dissolved in water. A synopsis of the instrumentation used, procedures followed, calibration practices, standards used, and a quality assurance and quality control program is presented. The report outlines the day-to-day operation of the Residual Gas Analyzer Model 200, Mass Analyzer Products Model 215–50, and ultralow vacuum extraction line along with the sample handling procedures, noble gas extraction and purification, instrument measurement procedures, instrumental data acquisition, and calculations for the conversion of raw data from the mass spectrometer into noble gas concentrations per unit mass of water analyzed. Techniques for the preparation of artificial dissolved gas standards are detailed and coupled to a quality assurance and quality control program to present the accuracy of the procedures used in the laboratory.

  1. Upscattering Cross Sections for Ultra Cold Neutrons from Gases

    NASA Astrophysics Data System (ADS)

    Seestrom, Susan J.; UCNτ Collaboration

    2014-09-01

    The scattering of ultracold neutrons (UCNs) to energies above the escape potential of a trap is called upscattering. Upscattering due to interaction with residual gases is a potential loss mechanism for UCNs stored in a trap that can impact the extracted neutron lifetime. We have developed a method for measuring the cross sections for UCN upscattering from gases stored in a small measurement cell. Upscattered neutrons are measured directly in a 3He ionization chamber and transmitted UCN strike a 10B-coated surface at the edges of the measurement cell. The transmitted UCNs are then counted with a HPGe gamma-ray detector that counts 478 keV γ-rays from the 10B(n , αγ) 7Li reaction. The analysis was guided by Monte Carlo descriptions of the LANL UCN source output. We will present cross sections measured for various noble and polyatomic gases, compare these results to calculated cross sections based on models of gas scattering kernels, and use these to estimate the impact of gas upscattering on the measurement of the neutron lifetime.

  2. Noble gas atmospheric monitoring at reprocessing facilities

    SciTech Connect

    Nakhleh, C.W.; Perry, R.T. Jr.; Poths, J.; Stanbro, W.D.; Wilson, W.B.; Fearey, B.L.

    1997-05-01

    The discovery in Iraq after the Gulf War of the existence of a large clandestine nuclear-weapon program has led to an across-the-board international effort, dubbed Programme 93+2, to improve the effectiveness and efficiency of International Atomic Energy Agency (IAEA) safeguards. One particularly significant potential change is the introduction of environmental monitoring (EM) techniques as an adjunct to traditional safeguards methods. Monitoring of stable noble gas (Kr, Xe) isotopic abundances at reprocessing plant stacks appears to be able to yield information on the burnup and type of the fuel being processed. To estimate the size of these signals, model calculations of the production of stable Kr, Xe nuclides in reactor fuel and the subsequent dilution of these nuclides in the plant stack are carried out for two case studies: reprocessing of PWR fuel with a burnup of 35 GWd/tU, and reprocessing of CAND fuel with a burnup of 1 GWd/tU. For each case, a maximum-likelihood analysis is used to determine the fuel burnup and type from the isotopic data.

  3. Nonequilibrium electron dynamics in noble metals

    NASA Astrophysics Data System (ADS)

    del Fatti, N.; Voisin, C.; Achermann, M.; Tzortzakis, S.; Christofilos, D.; Vallée, F.

    2000-06-01

    Electron-electron and electron-lattice interactions in noble metals are discussed in the light of two-color femtosecond pump-probe measurements in silver films. The internal thermalization of a nonequilibrium electron distribution created by intraband absorption of a pump pulse is followed by probing the induced optical property changes in the vicinity of the frequency threshold for the d band to Fermi surface transitions. This is shown to take place with a characteristic time constant of 350 fs, significantly shorter than previously reported in gold. This difference is ascribed to a weaker screening of the electron-electron interaction by the d-band electrons in silver than in gold. These results are in quantitative agreement with numerical simulations of the electron relaxation dynamics using a reduced static screening of the electron-electron Coulomb interaction, and including bound electron screening. Electron-lattice thermalization has been studied using a probe frequency out of resonance with the interband transitions. In both materials, the transient nonthermal nature of the electron distribution leads to the observation of a short-time delay reduction of the energy-loss rate of the electron gas to the lattice, in very good agreement with our theoretical model.

  4. Underground Sources of Radioactive Noble Gas

    SciTech Connect

    Hayes, James C.; Bowyer, Ted W.; Cordova, Elsa A.; Kirkham, Randy R.; Misner, Alex C.; Olsen, Khris B.; Woods, Vincent T.; Emer, Dudley

    2013-05-01

    It is well known that radon is present in relatively high concentrations below the surface of the Earth due to natural decay of uranium and thorium. However, less information is available on the background levels of other isotopes such as 133Xe and 131mXe produced via spontaneous fission of either manmade or naturally occurring elements. The background concentrations of radioxenon in the subsurface are important to understand because these isotopes potentially can be used to confirm violations of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) during an On-Site Inspection (OSI). Recently, Pacific Northwest National Laboratory (PNNL) measured radioxenon concentrations from the subsurface at the Nevada Nuclear Security Site (NNSS—formerly known as the Nevada Test Site) to determine whether xenon isotope background levels could be detected from spontaneous fission of naturally occurring uranium or legacy 240Pu as a result of historic nuclear testing. In this paper, we discuss the results of those measurements and review the sources of xenon background that must be taken into account during OSI noble gas measurements.

  5. Noble magnetic barriers in the ASDEX UG tokamak

    NASA Astrophysics Data System (ADS)

    Ali, Halima; Punjabi, Alkesh; Vazquez, Justin

    2010-02-01

    The second-order perturbation method of creating invariant tori inside chaos in Hamiltonian systems (Ali, H.; Punjabi, A. Plasma Phys. Contr. F. 2007, 49, 1565-1582) is applied to the axially symmetric divertor experiment upgrade (ASDEX UG) tokamak to build noble irrational magnetic barriers inside chaos created by resonant magnetic perturbations (m, n)=(3, 2)+(4, 3), with m and n the poloidal and toroidal mode numbers of the Fourier expansion of the magnetic perturbation. The radial dependence of the Fourier modes is ignored. The modes are considered to be locked and have the same amplitude δ. A symplectic mathematical mapping in magnetic coordinates is used to integrate magnetic field line trajectories in the ASDEX UG. Tori with noble irrational rotational transform are the last ones to be destroyed by perturbation in Hamiltonian systems. For this reason, noble irrational magnetic barriers are built inside chaos, and the strongest noble irrational barrier is identified. Three candidate locations for the strongest noble barrier in ASDEX UG are selected. All three candidate locations are chosen to be roughly midway between the resonant rational surfaces ψ32 and ψ43. ψ is the magnetic coordinate of the flux surface. The three candidate surfaces are the noble irrational surfaces close to the surface with q value that is a mediant of q=3/2 and 4/3, q value of the physical midpoint of the two resonant surfaces, and the q value of the surface where the islands of the two perturbing modes just overlap. These q values of the candidate surfaces are denoted by q MED, q MID, and q OVERLAP. The strongest noble barrier close to q MED has the continued fraction representation (CFR) [1;2,2,1∞] and exists for δ≤2.6599×10-4; the strongest noble barrier close to q MID has CFR [1;2,2,2,1∞] and exists for δ≤4.6311×10-4; and the strongest noble barrier close to q OVERLAP has CFR [1;2,2,6,2,1∞] and exists for δ≤1.367770×10-4. From these results, the strongest

  6. Equilibration of quantum gases

    NASA Astrophysics Data System (ADS)

    Farrelly, Terry

    2016-07-01

    Finding equilibration times is a major unsolved problem in physics with few analytical results. Here we look at equilibration times for quantum gases of bosons and fermions in the regime of negligibly weak interactions, a setting which not only includes paradigmatic systems such as gases confined to boxes, but also Luttinger liquids and the free superfluid Hubbard model. To do this, we focus on two classes of measurements: (i) coarse-grained observables, such as the number of particles in a region of space, and (ii) few-mode measurements, such as phase correlators. We show that, in this setting, equilibration occurs quite generally despite the fact that the particles are not interacting. Furthermore, for coarse-grained measurements the timescale is generally at most polynomial in the number of particles N, which is much faster than previous general upper bounds, which were exponential in N. For local measurements on lattice systems, the timescale is typically linear in the number of lattice sites. In fact, for one-dimensional lattices, the scaling is generally linear in the length of the lattice, which is optimal. Additionally, we look at a few specific examples, one of which consists of N fermions initially confined on one side of a partition in a box. The partition is removed and the fermions equilibrate extremely quickly in time O(1/N).

  7. Multiple scattering of matter waves: An analytic model of the refractive index for atomic and molecular gases

    SciTech Connect

    Lemeshko, Mikhail; Friedrich, Bretislav

    2010-08-15

    We present an analytic model of the refractive index for matter waves propagating through atomic or molecular gases. The model, which combines the Wentzel-Kramers-Brillouin (WKB) treatment of the long-range attraction with the Fraunhofer model treatment of the short-range repulsion, furnishes a refractive index in compelling agreement with recent experiments of Jacquey et al. [Phys. Rev. Lett. 98, 240405 (2007)] on Li atom matter waves passing through dilute noble gases. We show that the diffractive contribution, which arises from scattering by a two-dimensional 'hard core' of the potential, is essential for obtaining a correct imaginary part of the refractive index.

  8. Jet flows of reacting gases

    NASA Astrophysics Data System (ADS)

    Aliev, Farkhadzhan; Zhumaev, Zair Sh.

    The book presents fundamentals of the aerodynamic theory and calculation of straight gas jets. The discussion focuses on the flow structure and turbulent combustion of unmixed gases and thermal characteristics of the jet. The following three types of problems are considered: motion of unmixed chemically active gases; gas motion under conditions of chemical equilibrium; and motion of gases under conditions of finite-rate chemical reactions.

  9. Atomic forces between noble gas atoms, alkali ions, and halogen ions for surface interactions

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Outlaw, R. A.; Heinbockel, J. H.

    1988-01-01

    The components of the physical forces between noble gas atoms, alkali ions, and halogen ions are analyzed and a data base developed from analysis of the two-body potential data, the alkali-halide molecular data, and the noble gas crystal and salt crystal data. A satisfactory global fit to this molecular and crystal data is then reproduced by the model to within several percent. Surface potentials are evaluated for noble gas atoms on noble gas surfaces and salt crystal surfaces with surface tension neglected. Within this context, the noble gas surface potentials on noble gas and salt crystals are considered to be accurate to within several percent.

  10. Homogeneous Atomic Fermi Gases

    NASA Astrophysics Data System (ADS)

    Mukherjee, Biswaroop; Yan, Zhenjie; Patel, Parth B.; Hadzibabic, Zoran; Yefsah, Tarik; Struck, Julian; Zwierlein, Martin W.

    2017-03-01

    We report on the creation of homogeneous Fermi gases of ultracold atoms in a uniform potential. In the momentum distribution of a spin-polarized gas, we observe the emergence of the Fermi surface and the saturated occupation of one particle per momentum state: the striking consequence of Pauli blocking in momentum space for a degenerate gas. Cooling a spin-balanced Fermi gas at unitarity, we create homogeneous superfluids and observe spatially uniform pair condensates. For thermodynamic measurements, we introduce a hybrid potential that is harmonic in one dimension and uniform in the other two. The spatially resolved compressibility reveals the superfluid transition in a spin-balanced Fermi gas, saturation in a fully polarized Fermi gas, and strong attraction in the polaronic regime of a partially polarized Fermi gas.

  11. Noble Gas Tracing of Subsurface CO2 Origin and the Role of Groundwater as a CO2 Sink

    NASA Astrophysics Data System (ADS)

    Zhou, Z.; Ballentine, C. J.; Schoell, M.; Stevens, S. H.

    2003-12-01

    The source, generation, migration and accumulation of CO2 gas associated either alone or with hydrocarbons are unclear and therefore hard to predict. So far, noble gases provide one of the best tools to resolve this question, because they are conservative within the subsurface system. The atmosphere-derived noble gases dissolved in groundwater do not react with the rock system, while noble gases produced in the rock phase by radioactive decay or input from magmatic source are isotopically distinct and can be resolved from the dissolved air-derived noble gases. 10 samples were taken from a CO2-rich natural gas reservoir in Jackson Dome, Mississippi, USA to investigate its origin and extent of interaction with the groundwater system. The area lies within the Mississippi Interior Salt Basin. It is bounded on the north by the Pickens-Gilbertown fault system, the updip limit of the Jurassic Louann Salt unit, and on the south by basement highs of the Wiggins, South Mississippi, and Lasalle uplifts. We present compositional, stable isotope and noble gas results of Jackson Dome samples. Gas composition is 98.75-99.38% CO2, with small amounts of methane and nitrogen. CO2 content increases linearly with the decrease of CH4. d13C(CO2) in all samples ranges between -3.55 and -2.57 per mil, increasing with the increase of the CO2 content. Atmosphere-derived He contributions are negligible in all cases. 3He/4He ratios are between 4.27 and 5.01Ra, indicating a strong mantle signature. Crustal 4He in these samples therefore accounts for between 7.0% and 20.8%, the remainder being magmatic in origin. 40Ar/36Ar ratios are all above air ratio, ranging between 4071 and 6420. Air corrected 40Ar* vary between 92.7 and 95.4%, to give 4He/40Ar* ratios of between 1.26 and 2.52. This range is comparable with values estimated for the upper mantle. CO2/3He values are between 1.09E+9 and 4.62E+9, and also fall in the mantle range, indicating that the CO2 gas in Jackson Dome is also

  12. Noble gas paleotemperatures and water contents of stalagmites - a new extraction tool and a new paleoclimate proxy

    NASA Astrophysics Data System (ADS)

    Vogel, N.; Scheidegger, Y.; Brennwald, M. S.; Fleitmann, D.; Figura, S.; Wieler, R.; Kipfer, R.

    2012-04-01

    Stalagmites represent excellent multi-proxy paleoclimate archives as they cover long timescales and can be dated with high precision [e.g., 1]. The absolute temperature at which a stalagmite grew, can be deduced from the amounts of atmospheric noble gases dissolved in the stalagmite's fluid inclusion water (= noble gas temperature, NGT) [2-4]. We present technical advances towards more robust NGT determinations and also propose a new paleoclimate proxy, namely the stalagmite's water content, which is a "by-product" of NGT determination. Water contents and oxygen isotope records of two Holocene stalagmites from Socotra Island (Yemen) were found to vary systematically: progressively lighter oxygen is accompanied by decreasing water contents and vice versa. Via the oxygen isotope records [5] the stalagmites' water contents are linked to the amounts of precipitation on Socotra Island. High precipitation, i.e., high drip rates lead to homogeneous calcite growth with low porosity and therefore a small number of water-filled inclusions, i.e. low water contents. A reduction of drip water supply fosters irregular crystal growth with higher porosity, leading to higher water contents of the calcite (see also [6]). Therefore the stalagmites' water contents seem to record changes in drip water supply and, under favourable conditions, changes in regional precipitation. The current method to extract water and noble gases from stalagmite samples is experimentally challenging and subject to certain limitations (e.g., time-consuming sample preparation in a glove box, temperature restrictions for water extraction, and the often inadequate correction for air from residual air-filled inclusions [3, 4]). To overcome these limitations we have developed a new type of crusher directly attached to our noble gas line. It not only allows crushing and separating the samples into different grain size fractions in vacuo, but the separates can be individually heated to significantly higher

  13. Biomimetic synthesis of noble metal nanocrystals

    NASA Astrophysics Data System (ADS)

    Chiu, Chin-Yi

    At the nanometer scale, the physical and chemical properties of materials heavily depend on their sizes and shapes. This fact has triggered considerable efforts in developing controllable nanomaterial synthesis. The controlled growth of colloidal nanocrystal is a kinetic process, in which high-energy facets grow faster and then vanish, leading to a nanocrystal enclosed by low-energy facets. Identifying a surfactant that can selectively bind to a particular crystal facet and thus lower its surface energy, is critical and challenging in shape controlled synthesis of nanocrystals. Biomolecules exhibiting exquisite molecular recognition properties can be exploited to precisely engineer nanostructured materials. In the first part of my thesis, we employed the phage display technique to select a specific multifunctional peptide sequence which can bind on Pd surface and mediate Pd crystal nucleation and growth, achieving size controlled synthesis of Pd nanocrystals in aqueous solution. We further demonstrated a rational biomimetic approach to the predictable synthesis of nanocrystals enclosed by a particular facet in the case of Pt. Specifically, Pt {100} and Pt {111} facet-specific peptides were identified and used to synthesize Pt nanocubes and Pt nano-tetrahedrons, respectively. The mechanistic studies of Pt {111} facet-specific peptide had led us to study the facet-selective adsorption of aromatic molecules on noble metal surfaces. The discoveries had achieved the development of design strategies to select facet-selective molecules which can synthesize nanocrystals with expected shapes in both Pt and Pd system. At last, we exploited Pt facet-specific peptides and controlled the molecular interaction to produce one- and three- dimensional nanostructures composed of anisotropic nanoparticles in synthetic conditions without supramolecular pre-organization, demonstrating the full potential of biomolecules in mediating material formation process. My research on biomimetic

  14. Spectroscopic enhancement from noble mettalic nanoparticles

    NASA Astrophysics Data System (ADS)

    Tsai, Shu-Ju

    2011-12-01

    Resonant coupling of localized surface plasmon resonances (LSPRs) in noble metallic nanostructures to incident radiation and the related subject of localized behavior of electromagnetic waves are currently of great interest due to their potential application to sensors, biochemical assays, optical transmission, and photovoltaic devices. My thesis research is made up of two related parts. In part one I examined enhanced fluorescence in dye molecules in proximity to Ag nanostructures. In part two I studied the effect of Au nanostructure arrays on the performance of poly(3-hexylthiophene-2,5-diyl) : [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction (BHJ) organic solar cells (OSCs). Nanostructures were fabricated by two different methods: e-beam lithography (top down) and spray pyrolysis (bottom up). Using e-beam lithography, we produced arrays of nanostructures with well defined shapes, sizes, and spacings. By systematically varying these topographical parameters, we measured their effect on nanometer-sized metallic structure-enhanced fluorescence (nMEF) and on absorption and external quantum efficiency (EQE) in OSC devices as a function of optical wavelength. In analyzing experimental results, we carried out numerical simulations of the local electric field under incident light, across plasmonic resonances. The comparison between the calculated local field squared and measured fluorescence/EQE provides physical insight on the configuration-dependence of these two processes. Our results indicate that local field enhancement near nanostructures is dominant in nMEF, and that the local field is strongly affected by the substrate and device architectures. For the OSCs, both measurements and calculations show that absorbance within the active layer is enhanced only in a narrow band of wavelengths (˜640-720 nm) where the active layer is not very absorbing for our prototype nanopillar-patterned devices. The peak enhancement for 180 nm wide Au

  15. Gases in Seawater

    NASA Astrophysics Data System (ADS)

    Nightingale, P. D.; Liss, P. S.

    2003-12-01

    The annual gross and net primary productivity of the surface oceans is similar in size to that on land (IPCC, 2001). Marine productivity drives the cycling of gases such as oxygen (O2), dimethyl sulfide (DMS), carbon monoxide (CO), carbon dioxide (CO2), and methyl iodide (CH3I) which are of fundamental importance in studies of marine productivity, biogeochemical cycles, atmospheric chemistry, climate, and human health, respectively. For example, ˜30% of the world's population (1,570 million) is thought to be at risk of iodine-deficiency disorders that impair mental development (WHO, 1996). The main source of iodine to land is the supply of volatile iodine compounds produced in the ocean and then transferred to the atmosphere via the air-surface interface. The flux of these marine iodine species to the atmosphere is also thought to be important in the oxidation capacity of the troposphere by the production of the iodine oxide radical ( Alicke et al., 1999). A further example is that the net flux of CO2 from the atmosphere to the ocean, ˜1.7±0.5 Gt C yr-1, represents ˜30% of the annual release of anthropogenic CO2 to the atmosphere (IPCC, 2001). This net flux is superimposed on a huge annual flux (90 Gt C yr-1) of CO2 that is cycled "naturally" between the ocean and the atmosphere. The long-term sink for anthropogenic CO2 is recognized as transfer to the ocean from the atmosphere. A final example is the emission of volatile sulfur, in the form of DMS, from the oceans. Not only is an oceanic flux from the oceans needed to balance the loss of sulfur (a bioessential element) from the land via weathering, it has also been proposed as having a major control on climate due to the formation of cloud condensation nuclei (Charlson et al., 1987). Indeed, the existence of DMS and CH3I has been used as evidence in support of the Gaia hypothesis (Lovelock, 1979).There are at least four main processes that affect the concentration of gases in the water column: biological

  16. The role of soil air composition for noble gas tracer applications in tropical groundwater

    NASA Astrophysics Data System (ADS)

    Mayer, Simon; Jenner, Florian; Aeschbach, Werner; Weissbach, Therese; Peregovich, Bernhard; Machado, Carlos

    2016-04-01

    Dissolved noble gases (NGs) in groundwater provide a well-established tool for paleo temperature reconstruction. However, reliable noble gas temperature (NGT) determination needs appropriate assumptions or rather an exact knowledge of soil air composition. Deviations of soil air NG partial pressures from atmospheric values have already been found in mid latitudes during summer time as a consequence of subsurface oxygen depletion. This effect depends on ambient temperature and humidity and is thus expected to be especially strong in humid tropical soils, which was not investigated so far. We therefore studied NGs in soil air and shallow groundwater near Santarém (Pará, Brazil) at the end of the rainy and dry seasons, respectively. Soil air data confirms a correlation between NG partial pressures, the sum value of O2+CO2 and soil moisture contents. During the rainy season, we find significant NG enhancements in soil air by up to 7% with respect to the atmosphere. This is twice as much as observed during the dry season. Groundwater samples show neon excess values between 15% and 120%. Nearly all wells show no seasonal variations of excess air, even though the local river level seasonally fluctuates by about 8 m. Assuming atmospheric NG contents in soil air, fitted NGTs underestimate the measured groundwater temperature by about 1-2° C. However, including enhanced soil air NG contents as observed during the rainy season, resulting NGTs are in good agreement with local groundwater temperatures. Our presented data allows for a better understanding of subsurface NG variations. This is essential with regard to NG tracer applications in humid tropical areas, for which reliable paleoclimate data is of major importance for modern climate research.

  17. Noble gas and hydrocarbon tracers in multiphase unconventional hydrocarbon systems: Toward integrated advanced reservoir simulators

    NASA Astrophysics Data System (ADS)

    Darrah, T.; Moortgat, J.; Poreda, R. J.; Muehlenbachs, K.; Whyte, C. J.

    2015-12-01

    Although hydrocarbon production from unconventional energy resources has increased dramatically in the last decade, total unconventional oil and gas recovery from black shales is still less than 25% and 9% of the totals in place, respectively. Further, the majority of increased hydrocarbon production results from increasing the lengths of laterals, the number of hydraulic fracturing stages, and the volume of consumptive water usage. These strategies all reduce the economic efficiency of hydrocarbon extraction. The poor recovery statistics result from an insufficient understanding of some of the key physical processes in complex, organic-rich, low porosity formations (e.g., phase behavior, fluid-rock interactions, and flow mechanisms at nano-scale confinement and the role of natural fractures and faults as conduits for flow). Noble gases and other hydrocarbon tracers are capably of recording subsurface fluid-rock interactions on a variety of geological scales (micro-, meso-, to macro-scale) and provide analogs for the movement of hydrocarbons in the subsurface. As such geochemical data enrich the input for the numerical modeling of multi-phase (e.g., oil, gas, and brine) fluid flow in highly heterogeneous, low permeability formations Herein we will present a combination of noble gas (He, Ne, Ar, Kr, and Xe abundances and isotope ratios) and molecular and isotopic hydrocarbon data from a geographically and geologically diverse set of unconventional hydrocarbon reservoirs in North America. Specifically, we will include data from the Marcellus, Utica, Barnett, Eagle Ford, formations and the Illinois basin. Our presentation will include geochemical and geological interpretation and our perspective on the first steps toward building an advanced reservoir simulator for tracer transport in multicomponent multiphase compositional flow (presented separately, in Moortgat et al., 2015).

  18. Mineralogy and noble-gas signatures of the carbonate-rich lithology of the Tagish Lake carbonaceous chondrite: evidence for an accretionary breccia

    NASA Astrophysics Data System (ADS)

    Nakamura, Tomoki; Noguchi, Takaaki; Zolensky, Michael E.; Tanaka, Masahiko

    2003-02-01

    The carbonate-rich lithology of the Tagish Lake carbonaceous chondrite was characterized by noble-gas mass spectrometry, synchrotron X-ray diffraction analysis, and transmission and scanning electron microscopy. Noble-gas analysis was performed on two samples and the results showed that primordial noble gases are abundant and solar noble gases are absent in the samples of carbonate-rich lithology. The concentrations of Ne-A2 and -E in both samples are at the maximum level observed for CI and CM chondrites, suggesting high abundances of presolar diamonds and SiC/graphite, respectively. The cosmic-ray exposure age cannot be determined precisely, because the shielding depth of our Tagish Lake samples is unknown, but the minimum exposure age was determined to be 5.5±0.7 Myr on the basis of cosmogenic 21Ne concentrations and the highest 21Ne production rate. X-ray and electron-microscopic study showed that the carbonate-rich lithology is dominated by loosely packed porous matrix that consists mainly of fine-grained saponite and ferromagenesian carbonate. The matrix contains very few chondrules, but many fine-grained clasts having angular shape with longest dimensions up to 1 mm. The clasts differ from host matrix in both texture and mineralogy. They are massive, compacted material with porosity much lower than matrix and contain abundant magnetite and a coherent intergrowth of serpentine and saponite that is rare in matrix. The presence of texturally and mineralogically distinct clasts indicates that the carbonate-rich lithology is a breccia, but the absence of solar noble gases and impact-induced deformational features in host matrix distinguish it from an asteroid regolith breccia. Our results instead indicate that it is an accretionary breccia formed by simultaneous accretion of diverse objects in a massive dust cloud. The clasts often enclose chondrules and anhydrous silicate fragments such as low-iron-manganese-enriched olivines. This observation and their highly

  19. Understanding the interaction of injected CO2 and reservoir fluids in the Cranfield enhanced oil recovery (EOR) field (MS, USA) by non-radiogenic noble gas isotopes

    NASA Astrophysics Data System (ADS)

    Gyore, Domokos; Stuart, Finlay; Gilfillan, Stuart

    2016-04-01

    Identifying the mechanism by which the injected CO2 is stored in underground reservoirs is a key challenge for carbon sequestration. Developing tracing tools that are universally deployable will increase confidence that CO2 remains safely stored. CO2 has been injected into the Cranfield enhanced oil recovery (EOR) field (MS, USA) since 2008 and significant amount of CO2 has remained (stored) in the reservoir. Noble gases (He, Ne, Ar, Kr, Xe) are present as minor natural components in the injected CO2. He, Ne and Ar previously have been shown to be powerful tracers of the CO2 injected in the field (Györe et al., 2015). It also has been implied that interaction with the formation water might have been responsible for the observed CO2 loss. Here we will present work, which examines the role of reservoir fluids as a CO2 sink by examining non-radiogenic noble gas isotopes (20Ne, 36Ar, 84Kr, 132Xe). Gas samples from injection and production wells were taken 18 and 45 months after the start of injection. We will show that the fractionation of noble gases relative to Ar is consistent with the different degrees of CO2 - fluid interaction in the individual samples. The early injection samples indicate that the CO2 injected is in contact with the formation water. The spatial distribution of the data reveal significant heterogeneity in the reservoir with some wells exhibiting a relatively free flow path, where little formation water is contacted. Significantly, in the samples, where CO2 loss has been previously identified show active and ongoing contact. Data from the later stage of the injection shows that the CO2 - oil interaction has became more important than the CO2 - formation water interaction in controlling the noble gas fingerprint. This potentially provides a means to estimate the oil displacement efficiency. This dataset is a demonstration that noble gases can resolve CO2 storage mechanisms and its interaction with the reservoir fluids with high resolution

  20. Fractionation of the noble metals by physical processes

    NASA Astrophysics Data System (ADS)

    Ballhaus, Chris; Bockrath, Conny; Wohlgemuth-Ueberwasser, Cora; Laurenz, Vera; Berndt, Jasper

    2006-12-01

    During partial melting in the earth’s mantle, the noble metals become fractionated. Os, Ir, Ru, and Rh tend to remain in the mantle residue whereas Pt, Pd, and Re behave mildly incompatible and are sequestered to the silicate melt. There is consensus that sulfide plays a role in the fractionation process; the major noble metal repository in the mantle is sulfide, and most primitive mantle melts are sulfide-saturated when they leave their mantle sources. However, with sulfide-silicate partitioning, the fractionation cannot be modeled properly. All sulfide-silicate partition coefficients are so extremely high that a silicate melt segregating from a mantle source with residual sulfide should be largely platinum-group elements free. We offer a physical alternative to sulfide-silicate chemical partitioning and provide a mechanism of generating a noble metal-rich melt from a sulfide-saturated source: Because sulfide is at least partially molten at asthenospheric temperature, it will behave physically incompatible during melt segregation, and a silicate melt segregating from a mantle residue will entrain molten residual sulfide in suspension and incorporate it in the basaltic pool melt. The noble metal abundances of a basalt then become independent of sulfide-silicate chemical partitioning. They reflect the noble metal abundances in the drained sulfide fraction as well as the total amount of sulfide entrained. Contrary to convention, we suggest that a fertile, sulfide-rich mantle source has more potential to generate a noble metal-enriched basaltic melt than a refractory mantle source depleted by previous partial melting events.

  1. NMR and structural features of noble-metal fluorides

    SciTech Connect

    Gabuda, S.P.; Zemskov, S.V.

    1987-11-01

    NMR studies are reported on the structures of binary and other noble-metal fluorides. Revised measurements have been made on /sup 19/F chemical shifts and the anisotropy in them. A relationship is considered between the screening tensor for /sup 19/F and the electronic structure of the molecule or ion containing the noble-metal cation in the electronic configuration d/sup 6/, d/sup 8/, or d/sup 10/. The observed anomalous shifts in this class of compound are explained qualitatively in terms of paired electrons in filled d shells affecting the result within the framework of the classical theory of magnetic nuclear screening.

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

    SciTech Connect

    Bourg, I.C.; Sposito, G.

    2007-06-25

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

  3. Noble gas as tracers for CO2 deep input in petroleum reservoirs

    NASA Astrophysics Data System (ADS)

    Pujol, Magali; Stuart, Finlay; Gilfillan, Stuart; Montel, François; Masini, Emmanuel

    2016-04-01

    The sub-salt hydrocarbon reservoirs in the deep offshore part of the Atlantic Ocean passive margins are a new key target for frontier oil and gas exploration. Type I source rocks locally rich in TOC (Total Organic Carbon) combined with an important secondary connected porosity of carbonate reservoirs overlain by an impermeable salt layer gives rise to reservoirs with high petroleum potential. However, some target structures have been found to be mainly filled with CO2 rich fluids. δ13C of the CO2 is generally between -9 and -4 permil, compatible with a deep source (metamorphic or mantle). Understanding the origin of the CO2 and the relative timing of its input into reservoir layers in regard to the geodynamic context appears to be a key issue for CO2 risk evaluation. The inertness and ubiquity of noble gases in crustal fluids make them powerful tools to trace the origin and migration of mixed fluids (Ballentine and Burnard 2002). The isotopic signature of He, Ne and Ar and the elemental pattern (He to Xe) of reservoir fluid from pressurized bottom hole samples provide an insight into fluid source influences at each reservoir depth. Three main end-members can be mixed into reservoir fluids (e.g. Gilfillan et al., 2008): atmospheric signature due to aquifer recharge, radiogenic component from organic fluid ± metamorphic influence, and mantle input. Their relative fractionation provides insights into the nature of fluid transport (Burnard et al., 2012)and its relative migration timing. In the studied offshore passive margin reservoirs, from both sides of South Atlantic margin, a strong MORB-like magmatic CO2 influence is clear. Hence, CO2 charge must have occurred during or after lithospheric break-up. CO2 charge(s) history appears to be complex, and in some cases requires several inputs to generate the observed noble gas pattern. Combining the knowledge obtained from noble gas (origin, relative timing, number of charges) with organic geochemical and thermodynamic

  4. Noble Gas Isotopic Evidence for Primordial Evolution of the Earth's Atmosphere in Three Distinct Stages

    NASA Astrophysics Data System (ADS)

    Harper, C. L., Jr.; Jacobsen, S. B.

    1995-09-01

    The deep Earth is the key to understanding the primordial evolution of the Earth's atmosphere. However the atmosphere was not derived by degassing of the Earth, as widely held. Isotopic characterization of mantle noble gases and modeling based on this information [1] suggests the atmosphere experienced a 3-stage early history. This follows from 5 basic observations: (i) Ne in the mantle is solar-like, with light (high) 20Ne/22Ne relative to the atmosphere [2]; (ii) mantle Xe has higher 128Xe/130Xe than the atmosphere [3], which carries an extreme heavy isotope enriched mass fractionation signature of >3%/amu (iii) most of the radiogenic Xe from l29I and 244Pu decay in the Earth is not present either in the mantle or in the atmosphere; (iv) the inferred abundances of noble gases in the deep Earth "plume source" are insufficient to generate the present atmospheric abundances, even for whole mantle degassing; and (v) mantle noble gases indicate a 2 component structure, with solar light gases (He and Ne) and planetary heavy gases [4]. The present day noble gas budgets (and likely also N2) must derive from late accretion of a volatile-rich "veneer." This is stage III. Stage II is a naked (no atmosphere) epoch indicated by evidence for Hadean degassing of 244Pu (T1/2 = 80 Ma) fission Xe from the whole mantle, which was not retained in the present atmosphere. The naked stage must have lasted for more than ~200 Ma, and was supported by the early intense solar EUV luminosity. Stage I, a massive solar-composition protoatmosphere, occurred during the Earth's early accretion phase. Its existence is indicated by the presence of the solar gas component in the Earth. This is not attributable to subduction of solar wind rich cosmic dust, or solar wind irradiation of coagulating objects. It is best explained by accretion of a solar composition atmosphere from the nebula. This provided a thermal blanket supporting a magma ocean in which solar gases dissolved. Under these conditions

  5. Assessing Compositional Variability and Migration of Natural Gas in the Antrim Shale in the Michigan Basin Using Noble Gas Geochemistry

    NASA Astrophysics Data System (ADS)

    Wen, T.; Castro, M. C.; Ellis, B. R.; Hall, C. M.; Lohmann, K. C.

    2015-12-01

    The Antrim Shale was one of the first economic shale gas plays in the U.S. and has been actively produced since the 1980's. While previous studies suggest co-produced water in the Antrim is a mixture of brine from deeper formations and freshwater recharge, the extent of water-gas interactions has yet to be determined. The extent and source of thermogenic methane in the Antrim Shale are also under debate. This study uses stable noble gases' (He, Ne, Ar, Kr, Xe) isotopic ratios and their volume fractions from the Antrim Shale gases to assess compositional variability and vertical fluid migration, in addition to distinguishing between the presence of thermogenic versus biogenic methane. R/Ra values of Antrim Shale gases (where R and Ra are the measured and atmospheric 3He/4He ratios, respectively) vary from 0.01 to 0.34 suggesting dominant crustal 4He in addition to minor mantle and atmospheric He. Elevated 20Ne/22Ne ratios (up to 10.4) point to mantle Ne. Similarly crustal 21Ne*, 40Ar* and 136Xe* are also suggested. High variability of noble gas signatures in the Antrim Shale are observed, which are mainly due to variable noble gas input from deep brines and, to a smaller extent, variable in-situ production in the Antrim Shale. Estimated 4He ages considering external 4He flux for Antrim water match well with timings of three major glaciation periods (Wisconsin, Illinoian and Kansan glaciations) in the Michigan Basin, suggesting that all our Antrim samples were more or less influenced by glaciation recharge. Consistency in measured and predicted 40Ar/36Ar assuming Ar release temperatures ≥ 250°C supports a thermogenic origin for the majority of the methane in our Antrim Shale gas samples. Thermogenic methane is likely to originate at greater depth, either from deeper portions of the Antrim Shale in the central Michigan Basin or from deeper formations underlying the Antrim Shale, as the thermal maturity of the Antrim Shale in our study area is low.

  6. Evaluating the accretion of meteoritic debris and interplanetary dust particles in the GPC-3 sediment core using noble gas and mineralogical tracers

    NASA Astrophysics Data System (ADS)

    Darrah, Thomas H.; Poreda, Robert J.

    2012-05-01

    Extraterrestrial (ET) noble gases (helium and neon) in 35 sediment samples from Central Pacific core LL-44 GPC-3 demonstrate the variable flux of interplanetary dust particles (IDPs) and major meteorite impacts over the past 70 Ma (21-72 Ma). Spinel mineralogical and chemical compositions clearly distinguish major impact events from the continuous flux of IDPs, including the well-established Cretaceous/Tertiary (K/T) and late Eocene (E/O) impact boundaries. No spinel grains with chemical or mineralogical evidence of a distinctly ET origin were found in an extensive survey of 'background' samples (i.e. non E/O or K/T boundary) suggesting that either the carrier grains for ET noble gas occur within the Fe-Ti oxide mineral fraction observed in this study (found to include ilmenite and ulvospinel) or are too small for identification by SEM. The presence of ilmenite and ulvospinel suggest lunar regolith is a potential source for ET noble gas-rich particles. Noble gas analysis on both the EMF (extractable magnetic fraction) and the Bulk minus EMF (Bulk - EMF) show that the He and Ne compositions are consistent with partially degassed noble gas signatures of zero-age magnetic grains (Z-MAG) and stratospheric interplanetary dust particles (IDPs). Conclusive evidence for a 'planetary' (Ne-A) noble gas signature is found only in the bulk sediments at the K/T boundary, although all GPC-3 K/T fractions (Bulk, EMF, and HF Digestion) plot along a mixing line between planetary (Ne-A) and solar wind (SW). Spinels from major impact boundaries (K/T; E/O) exhibit dendritic texture and elevated [Ni], consistent with previous reports. In contrast to the otherwise consistent [3He] signal from IDPs, the [3He] at the known impact boundaries (K/T and E/O) actually decreases. These anomalously low [3He] are accompanied by significantly elevated [Ne] and significantly lower (3He/20Ne)solar ratios (˜10× lower) produced by both preferentially degassing of He relative to Ne at times of

  7. Noble Metal Nanoparticle-loaded Mesoporous Oxide Microspheres for Catalysis

    NASA Astrophysics Data System (ADS)

    Jin, Zhao

    Noble metal nanoparticles/nanocrystals have attracted much attention as catalysts due to their unique characteristics, including high surface areas and well-controlled facets, which are not often possessed by their bulk counterparts. To avoid the loss of their catalytic activities brought about by their size and shape changes during catalytic reactions, noble metal nanoparticles/nanocrystals are usually dispersed and supported finely on solid oxide supports to prevent agglomeration, nanoparticle growth, and therefore the decrease in the total surface area. Moreover, metal oxide supports can also play important roles in catalytic reactions through the synergistic interactions with loaded metal nanoparticles/nanocrystals. In this thesis, I use ultrasonic aerosol spray to produce hybrid microspheres that are composed of noble metal nanoparticles/nanocrystals embedded in mesoporous metal oxide matrices. The mesoporous metal oxide structure allows for the fast diffusion of reactants and products as well as confining and supporting noble metal nanoparticles. I will first describe my studies on noble metal-loaded mesoporous oxide microspheres as catalysts. Three types of noble metals (Au, Pt, Pd) and three types of metal oxide substrates (TiO2, ZrO2, Al 2O3) were selected, because they are widely used for practical catalytic applications involved in environmental cleaning, pollution control, petrochemical, and pharmaceutical syntheses. By considering every possible combination of the noble metals and oxide substrates, nine types of catalyst samples were produced. I characterized the structures of these catalysts, including their sizes, morphologies, crystallinity, and porosities, and their catalytic performances by using a representative reduction reaction from nitrobenzene to aminobenzene. Comparison of the catalytic results reveals the effects of the different noble metals, their incorporation amounts, and oxide substrates on the catalytic abilities. For this particular

  8. Field Enhancement using Noble Metal Structures

    NASA Astrophysics Data System (ADS)

    Liu, Benliang

    Resonance may be one of the most fundamental rules of nature. Electromagnetic resonance at nanometer scale could produce a giant field enhancement at optical frequency, providing a way to measure and control the process of atoms and molecules at single molecule scale. For example, the giant field enhancement would provide single molecule sensitivity for Raman scattering, which provides unique tools in measuring the quantity in extremely low concentration. In addition, light-emitting diodes could have high brightness but low input power that would be revolutionary in the optoelectronic industry. Although light enhancement is promising in several key technology areas, there are several challenges remain to be tackled. In particular, since the field enhancement is so strongly geometry dependent that slight modification of the geometry can lead to large variations in the outcome, a thorough understanding in how the geometry of the structure affects the field enhancement and creating proper methods to fabricate these structures reproducibly is of most importance. This thesis is devoted to design, fabrication and characterization of field enhancement generated on the surface of noble metals such as silver or gold with 1D structure. The s-polarized field enhancement arising from one-dimensional metal gratings is designed and optimized by using Rigorous Coupling Wave Analysis (RCWA). After optimization, the strongest enhancement factor is found to be 9.7 for 514nm wavelength light. The theoretical results arc confirmed by angle-dependent reflectivity measurements and the experimental results are found to support the theory. A novel single slit structure employing surface plasmon polaritons (SPPs) for enhancing the electric field is studied. SPPs are first generated on a 50 nm thick metal film using attenuated total reflection coupling, and they are subsequently coupled to the cavity mode induced by the single slit. As a result, the field enhancement is found at least 3

  9. Environmental implications of anesthetic gases.

    PubMed

    Yasny, Jeffrey S; White, Jennifer

    2012-01-01

    For several decades, anesthetic gases have greatly enhanced the comfort and outcome for patients during surgery. The benefits of these agents have heavily outweighed the risks. In recent years, the attention towards their overall contribution to global climate change and the environment has increased. Anesthesia providers have a responsibility to minimize unnecessary atmospheric pollution by utilizing techniques that can lessen any adverse effects of these gases on the environment. Moreover, health care facilities that use anesthetic gases are accountable for ensuring that all anesthesia equipment, including the scavenging system, is effective and routinely maintained. Implementing preventive practices and simple strategies can promote the safest and most healthy environment.

  10. Geostatistical Analysis of Tritium, 3H/3He Age and Noble Gas Derived Parameters in California Groundwater

    NASA Astrophysics Data System (ADS)

    Visser, A.; Singleton, M. J.; Moran, J. E.; Fram, M. S.; Kulongoski, J. T.; Esser, B. K.

    2014-12-01

    Key characteristics of California groundwater systems related to aquifer vulnerability, sustainability, recharge locations and mechanisms, and anthropogenic impact on recharge, are revealed in a spatial geostatistical analysis of the data set of tritium, dissolved noble gas and helium isotope analyses collected for the California State Water Resources Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) and California Aquifer Susceptibility (CAS) programs. Over 4,000 tritium and noble gas analyses are available from wells across California. 25% of the analyzed samples contained less than 1 pCi/L indicating recharge occurred before 1950. The correlation length of tritium concentration is 120 km. Nearly 50% of the wells show a significant component of terrigenic helium. Over 50% of these samples show a terrigenic helium isotope ratio (Rter) that is significantly higher than the radiogenic helium isotope ratio (Rrad = 2×10-8). Rter values of more than three times the atmospheric isotope ratio (Ra = 1.384×10-6) are associated with known faults and volcanic provinces in Northern California. In the Central Valley, Rter varies from radiogenic to 2.25 Ra, complicating 3H/3He dating. The Rter was mapped by kriging, showing a correlation length of less than 50 km. The local predicted Rter was used to separate tritiogenic from atmospheric and terrigenic 3He. Regional groundwater recharge areas, indicated by young groundwater ages, are located in the southern Santa Clara Basin and in the upper LA basin and in the eastern San Joaquin Valley and along unlined canals carrying Colorado River water. Recharge in California is dominated by agricultural return flows, river recharge and managed aquifer recharge rather than precipitation excess. Combined application of noble gases and other groundwater tracers reveal the impact of engineered groundwater recharge and prove invaluable for the study of complex groundwater systems. This work was performed under the

  11. The Origin of Noble Gas Isotopic Heterogeneity in Icelandic Basalts

    NASA Technical Reports Server (NTRS)

    Dixon, E. T.; Honda, M.; McDougall, I.

    2001-01-01

    Two models for generation of heterogeneous He, Ne and Ar isotopic ratios in Icelandic basalts are evaluated using a mixing model and the observed noble gas elemental ratios in Icelandic basalts,Ocean island Basalt (OIBs) and Mid-Ocean Ridge Basalt (MORBs). Additional information is contained in the original extended abstract.

  12. Making A Noble-Metal-On-Metal-Oxide Catalyst

    NASA Technical Reports Server (NTRS)

    Miller, Irvin M.; Davis, Patricia P.; Upchurch, Billy T.

    1989-01-01

    Catalyst exhibits superior performance in oxidation of CO in CO2 lasers. Two-step process developed for preparing platinum- or palladium-on-tin-oxide catalyst for recombination of CO and O2, decomposition products that occur in high-voltage discharge region of closed-cycle CO2 laser. Process also applicable to other noble-metal/metal-oxide combinations.

  13. Oxygen adsorption at noble metal/TiO2 junctions

    NASA Astrophysics Data System (ADS)

    Hossein-Babaei, F.; Alaei-Sheini, Navid; Lajvardi, Mehdi M.

    2016-03-01

    Electric conduction in titanium dioxide is known to be oxygen sensitive and the conductivity of a TiO2 ceramic body is determined mainly by the concentration of its naturally occurring oxygen vacancy. Recently, fabrications and electronic features of a number of noble metal/TiO2-based electronic devices, such as solar cells, UV detectors, gas sensors and memristive devices have been demonstrated. Here, we investigate the effect of oxygen adsorption at the noble metal/TiO2 junction in such devices, and show the potentials of these junctions in chemical sensor fabrication. The polycrystalline, poly-phase TiO2 layers are grown by the selective and controlled oxidation of titanium thin films vacuum deposited on silica substrates. Noble metal thin films are deposited on the oxide layers by physical vapor deposition. Current-voltage (I-V) diagrams of the fabricated devices are studied for Ag/, Au/, and Pt/TiO2 samples. The raw samples show no junction energy barrier. After a thermal annealing in air at 250° C, I-V diagrams change drastically. The annealed samples demonstrate highly non-linear I-V indicating the formation of high Schottky energy barriers at the noble metal/TiO2 junctions. The phenomenon is described based on the effect of the oxygen atoms adsorbed at the junction.

  14. Comparison of various stopping gases for 3He-based position sensitive neutron detectors

    NASA Astrophysics Data System (ADS)

    Doumas, A.; Smith, G. C.

    2012-05-01

    A range of solid state, scintillator and gas based detectors are being developed for use at the next generation of high flux neutron facilities. Since gas detectors are expected to continue to play a key role in future specific thermal neutron experiments, a comparison of the performance characteristics of prospective stopping gases is beneficial. Gas detectors typically utilize the reaction 3He(n,p)t to detect thermal neutrons; the 3He gas is used in a mixture containing a particular stopping gas in order to maintain relatively short ranges for the proton and triton pair emitted from the n-3He reaction. Common stopping gases include hydrocarbons (e.g. propane), carbon tetrafluoride, and noble gases such as argon and xenon. For this study, we utilized the Monte Carlo simulation code "Stopping and Range of Ions in Matter" to analyze the expected behavior of argon, xenon, carbon dioxide, difluoroethane and octafluoropropane as stopping gases for thermal neutron detectors. We also compare these findings to our previously analyzed performance of propane, butane and carbon tetrafluoride. A discussion of these gases includes their behavior in terms of proton and triton range, ionization distribution and straggle.

  15. Synthesis and characterization of fluorescence-labelled silica core-shell and noble metal-decorated ceria nanoparticles

    PubMed Central

    Rennhak, Markus; Reller, Armin

    2014-01-01

    Summary The present review article covers work done in the cluster NPBIOMEM in the DFG priority programme SPP 1313 and focuses on synthesis and characterization of fluorescent silica and ceria nanoparticles. Synthetic methods for labelling of silica and polyorganosiloxane/silica core–shell nanoparticles with perylenediimide derivatives are described, as well as the modification of the shell with thiol groups. Photometric methods for the determination of the number of thiol groups and an estimate for the number of fluorescent molecules per nanoparticles, including a scattering correction, have been developed. Ceria nanoparticles decorated with noble metals (Pt, Pd, Rh) are models for the decomposition products of automobile catalytic converters which appear in the exhaust gases and finally interact with biological systems including humans. The control of the degree of agglomeration of small ceria nanoparticles is the basis for their synthesis. Almost monodisperse agglomerates (40 ± 4–260 ± 40 nm diameter) can be prepared and decorated with noble metal nanoparticles (2–5 nm diameter). Fluorescence labelling with ATTO 647N gave the model particles which are now under biophysical investigation. PMID:25671137

  16. Synthesis and characterization of fluorescence-labelled silica core-shell and noble metal-decorated ceria nanoparticles.

    PubMed

    Herrmann, Rudolf; Rennhak, Markus; Reller, Armin

    2014-01-01

    The present review article covers work done in the cluster NPBIOMEM in the DFG priority programme SPP 1313 and focuses on synthesis and characterization of fluorescent silica and ceria nanoparticles. Synthetic methods for labelling of silica and polyorganosiloxane/silica core-shell nanoparticles with perylenediimide derivatives are described, as well as the modification of the shell with thiol groups. Photometric methods for the determination of the number of thiol groups and an estimate for the number of fluorescent molecules per nanoparticles, including a scattering correction, have been developed. Ceria nanoparticles decorated with noble metals (Pt, Pd, Rh) are models for the decomposition products of automobile catalytic converters which appear in the exhaust gases and finally interact with biological systems including humans. The control of the degree of agglomeration of small ceria nanoparticles is the basis for their synthesis. Almost monodisperse agglomerates (40 ± 4-260 ± 40 nm diameter) can be prepared and decorated with noble metal nanoparticles (2-5 nm diameter). Fluorescence labelling with ATTO 647N gave the model particles which are now under biophysical investigation.

  17. Identifying the Sources of Methane in Shallow Groundwaters in Parker and Hood Counties, Texas through Noble Gas Signatures

    NASA Astrophysics Data System (ADS)

    Wen, T.; Castro, M. C.; Nicot, J. P.; Hall, C. M.; Mickler, P. J.; Darvari, R.

    2015-12-01

    With rising demands for cleaner domestic energy resources, horizontal drilling and hydraulic fracturing techniques in unconventional hydrocarbon exploration have been extensively developed. However, the observation that some water wells have showed elevated concentrations of dissolved methane and other light hydrocarbons has caused public concern regarding unconventional energy extraction. In this contribution, we present noble gas data of production shale gases from the Barnett and Strawn Formations, as well as nearby groundwater samples in south-central Texas. The Barnett Shale located in the Fort Worth Basin at an average depth of ~2300 m is one of the most prominent shale gas plays in the U.S. This DOE-sponsored study explores the potential of noble gases for fingerprinting shale gas and thus, for identifying the sources of gas in aquifers overlying the Barnett Shale, due either to natural hydrocarbon occurrences or potentially related to gas production from unconventional energy resources. A total of 35 groundwater samples were collected in Parker and Hood counties in areas where high amounts of methane (>10 mg/L) were detected in shallow groundwater. Two gas samples were also collected directly from groundwater wells where bubbling methane was present. Preliminary results show that He concentrations in water samples, in excess of up to three orders of magnitude higher than expected atmospheric values are directly correlated with methane concentrations. 3He/4He ratio values vary from 0.030 to 0.889 times the atmospheric ratio with the lowest, more pure radiogenic contributions being associated with highest methane levels. The presence of crustally-produced radiogenic 40Ar is also apparent in groundwater samples with 40Ar/36Ar ratios up to 316. A combined analysis of 40Ar/36Ar ratios from groundwater wells bubbling gas and that of shale gas suggests that the source of this methane is not the heavily exploited Barnett Shale, but rather, the Strawn Formation.

  18. Noble gas component organization in Apollo 14 breccia 14318: /sup 129/I and /sup 244/Pu regolith chronology

    SciTech Connect

    Swindle, T.D.; Caffee, M.W.; Hohenberg, C.M.; Hudson, G.B.; Laul, J.C.; Simon, S.B.; Papike, J.J.

    1985-02-15

    Noble gas, petrological, and chemical studies made on grain-size separates from lunar regolith breccia 14318 demonstrate that the noble gases are organized into two functional components, volume-correlated and surface-correlated. As in regolith breccia 14301, volume-correlated xenon in 14318 is primarily spallation-derived and the surface-correlated component contains not only solar wind xenon but also significant amounts of ''parentless' xenon from the fission of now extinct /sup 244/Pu and the decay of now extinct /sup 129/I (''parentless'' means the daughter products were incorporated onto grain surfaces following decay of the parent nuclide elsewhere). The ratio of /sup 129/Xe//sup 136/Xe in the total surface-correlated parentless component, as identified in grain-size analysis, is substantially higher than in the least tightly bound parentless component identified in stepwise heating analyses, confirming the trend seen in 14301. If the order of release of gases in stepwise heating is related to the order of incorporation in the simplest way (first in, last out), incorporation of these grain-surface components was probably time-ordered. The /sup 129/Xe//sup 136/Xe ratio in each identifiable parentless component would then be characteristic of the xenon available for surface adsorption at the particular time of acquisition. Continuous variations in this ratio further suggest that incorporation of the parentless xenon was closely coupled with production. Such observations provide the basis for a new chronometer from which we conclude that acquisition of parentless xenon was an ongoing process spanning at least 90 m.y., beginning no more than 44 +- 34 m.y. after the formation of the most meteorites and possibly predating xenon acquisition for the earth.

  19. The Role of Boron-Chloride and Noble Gas Isotope Ratios in TVZ Geothermal Systems

    SciTech Connect

    Hulston, J.R.

    1995-01-01

    The model of the geothermal system in which deep circulating groundwater containing noble gases, at air saturated water concentrations, mixes with hot fluids of mantle origin at depth, is extended to include the effect of interaction of the ascending fluid with both solid and gaseous phases of basement (or other) rocks en route to the surface. It is demonstrated that this interaction is responsible for most of the CO{sub 2} in the Taupo Volcanic Zone (TVZ) geothermal systems. It is proposed that the modeling of this interaction might be accomplished by techniques similar to those used for the understanding of the oxygen isotope shift found in geothermal systems. The water rock interaction experiments of Ellis and Mahon (1964, 1967) provides some data on the kinetic rates for B and Cl dissolution from rocks likely to be encountered in the geothermal system, but further information on the behavior of B may be needed. If these problems can be overcome this modeling technique has promise for the estimation of the recharge of geothermal systems and hence the sustainability of these systems.

  20. Geostatistical analysis of tritium, groundwater age and other noble gas derived parameters in California.

    PubMed

    Visser, A; Moran, J E; Hillegonds, Darren; Singleton, M J; Kulongoski, Justin T; Belitz, Kenneth; Esser, B K

    2016-03-15

    Key characteristics of California groundwater systems related to aquifer vulnerability, sustainability, recharge locations and mechanisms, and anthropogenic impact on recharge are revealed in a spatial geostatistical analysis of a unique data set of tritium, noble gases and other isotopic analyses unprecedented in size at nearly 4000 samples. The correlation length of key groundwater residence time parameters varies between tens of kilometers ((3)H; age) to the order of a hundred kilometers ((4)Heter; (14)C; (3)Hetrit). The correlation length of parameters related to climate, topography and atmospheric processes is on the order of several hundred kilometers (recharge temperature; δ(18)O). Young groundwater ages that highlight regional recharge areas are located in the eastern San Joaquin Valley, in the southern Santa Clara Valley Basin, in the upper LA basin and along unlined canals carrying Colorado River water, showing that much of the recent recharge in central and southern California is dominated by river recharge and managed aquifer recharge. Modern groundwater is found in wells with the top open intervals below 60 m depth in the southeastern San Joaquin Valley, Santa Clara Valley and Los Angeles basin, as the result of intensive pumping and/or managed aquifer recharge operations.

  1. Updated compilations of electron scattering from ground-state, noble gas atoms

    NASA Astrophysics Data System (ADS)

    Biagi, S. F.

    2011-10-01

    An updated analysis of the cross sections for electron scattering from ground state atoms for noble gases in the energy range from thermalto 10 MeV is outlined. The work was driven by the necessity tounderstand the Penning transfers and light emission in detectors of high energy particles and dark matter. The published experimental data for electron scattering up to 2010 have been used in the analysis. Recent, theoretically improved cross sections have been used in the important threshold region for both the singlet and triplet states. Experimental or theoretical oscillator strengths and BEF scaling have been used above the resonance region for the singlet states. The number of excitation levels considered (typically about 40) is chosen so that the sum of the oscillator strengths for the considered levels is within a few percent of the theoretical sum rule. The resulting total cross sections are within a few percent of the measured values, and the calculated Fano factors are consistent with available data. These data are now available on the LXCat website. This work is part of the RD51 collaboration at CERN.

  2. Ground-Water Temperature, Noble Gas, and Carbon Isotope Data from the Espanola Basin, New Mexico

    USGS Publications Warehouse

    Manning, Andrew H.

    2009-01-01

    Ground-water samples were collected from 56 locations throughout the Espanola Basin and analyzed for general chemistry (major ions and trace elements), carbon isotopes (delta 13C and 14C activity) in dissolved inorganic carbon, noble gases (He, Ne, Ar, Kr, Xe, and 3He/4He ratio), and tritium. Temperature profiles were measured at six locations in the southeastern part of the basin. Temperature profiles suggest that ground water generally becomes warmer with distance from the mountains and that most ground-water flow occurs at depths 50 years old, consistent with the 14C ages. Terrigenic He (Heterr) concentrations in ground water are high (log Delta Heterr of 2 to 5) throughout much of the basin. High Heterr concentrations are probably caused by in situ production in the Tesuque Formation from locally high concentrations of U-bearing minerals (Northeast zone only), or by upward diffusive/advective transport of crustal- and mantle-sourced He possibly enhanced by basement piercing faults, or by both. The 3He/4He ratio of Heterr (Rterr) is commonly high (Rterr/Ra of 0.3-2.0, where Ra is the 3He/4He ratio in air) suggesting that Espanola Basin ground water commonly contains mantle-sourced He. The 3He/4He ratio of Heterr is generally the highest in the western and southern parts of the basin, closest to the western border fault system and the Quaternary to Miocene volcanics of the Jemez Mountains and Cerros del Rio.

  3. 40 CFR 1065.750 - Analytical gases.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Analytical gases. 1065.750 Section... ENGINE-TESTING PROCEDURES Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.750 Analytical gases. Analytical gases must meet the accuracy and purity specifications of...

  4. New evidence for a magmatic origin of some gases in the Geysers geothermal reservoir

    SciTech Connect

    Truesdell, A.H.; Kennedy, B.M.; Walters, M.A.; D'Amore, F.

    1994-01-20

    The Geysers vapor-dominated geothermal reservoir is known to have a wide range of gas concentrations in steam (<100 to >75,000 ppmw), but the variations in gas compositions and the origin of the gases have been little studied. Low gas concentrations and steam isotopes similar to meteoric waters are found in the SE Geysers, but steam high in gas and HCI from a high temperature reservoir (HTR) in the NW Geysers has been thought to be related to metamorphic or magmatic brine. New analyses of noble gas isotopes show that the highest gas steam from the HTR has high {sup 3}He/{sup 4}He (8.3 Ra), and very low {sup 36}Ar and radiogenic {sup 40}Ar/{sup 4}He, indicating a strong magmatic component and essentially no atmospheric or crustal noble gases. Other samples from the HTR show various amounts of atmospheric dilution of the magmatic gas and lower HCI and total gas contents. The occurrence of steam in the NW Geysers highly enriched in heavy isotopes of oxygen and hydrogen supports the indications of remnant magmatic fluid: The existence of this fluid strongly suggests that the HTR was formed by rapid heating and catastrophic boiling resulting from injection of magma.

  5. Nuclear monitoring by nonradioactive noble gas sampling and analysis

    SciTech Connect

    Fearey, B.L.; Nakhleh, C.W.; Stanbro, W.D.

    1997-10-01

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The perceived importance of measuring the xenon and krypton isotopics of nuclear activities has increased substantially in recent years. We have performed a systems analysis and theoretical simulation of the production, atmospheric dispersion, and isotopic abundances of noble-gas fission products, addressing several questions of interest, including: the relative isotopic variation as a function of nuclear fuel composition, reactor operational history, reactor type, distance from stack, and ambient meteorological conditions. Of particular importance in this analysis was the question of back-calculating process parameters of interest given noble-gas isotopic data. An analysis of the effect of measurement uncertainties was also performed. The results of these analyses indicate that this monitoring concept should be experimentally feasible.

  6. Identification of potential protein markers of noble rot infected grapes.

    PubMed

    Lorenzini, Marilinda; Millioni, Renato; Franchin, Cinzia; Zapparoli, Giacomo; Arrigoni, Giorgio; Simonato, Barbara

    2015-07-15

    The evaluation of Botrytis cinerea as noble rot on withered grapes is of great importance to predict the wine sensory/organoleptic properties and to manage the winemaking process of Amarone, a passito dry red wine. This report describes the first proteomic analysis of grapes infected by noble rot under withering conditions to identify possible markers of fungal infection. 2-D gel electrophoresis revealed that protein profiles of infected and not infected grape samples are significantly different in terms of number of spots and relative abundance. Protein identification by MS analysis allowed to identify only in infected berries proteins of B. cinerea that represent potential markers of the presence of the fungus in the withered grapes.

  7. Noble Metal-Iron Oxide Hybrid Nanomaterials: Emerging Applications.

    PubMed

    Leung, Ken Cham-Fai; Xuan, Shouhu

    2016-02-01

    This account provides an overview of current research activities that focus on the synthesis and applications of nanomaterials from noble metal (e.g., Au, Ag, Pd) and iron oxide (Fe3O4) hybrids. An introduction to the synthetic strategies that have been developed for generating M-Fe3O4 nanomaterials with different novel structures is presented. Surface functionalization and bioconjugation of these hybrid nanoparticles and nanocomposites are also reviewed. The utilization of the advantageous properties of both noble metals and iron oxide for a variety of applications, such as theranostics, gene delivery, biosensing, cell sorting, bioseparation, and catalysis, is discussed and highlighted. Finally, future trends and perspectives of these sophisticated nanocomposites are outlined. The fundamental requirements underpinning the effective preparation of M-Fex Oy hybrid nanomaterials shed light on the future development of heterogeneous catalysts, nanotheranostics, nanomedicines, and other chemical technologies.

  8. Noble Gas Tracing of Fluid Transport in Shale Reservoirs

    NASA Astrophysics Data System (ADS)

    Heath, J. E.; Gardner, W. P.; Kuhlman, K. L.; Robinson, D. G.; Bauer, S. J.

    2014-12-01

    We investigate fluid transport mechanisms in a shale reservoir using natural noble gas tracers. Noble gas tracing is promising due to sensitivity of transport to: pore structure and sizes; phase partitioning between groundwater and liquid and gaseous hydrocarbons; and deformation from hydraulic fracturing and creation of surface area. A time-series of over thirty wellhead fluid samples were collected from two hydraulically-fractured wells with different oil-to-gas ratios, along with production data (i.e., flowrate and pressure). Tracer and production data sets can be combined to infer production flow regimes, to estimate reservoir transport parameters, and to improve forecasts of production decline. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  9. Method for low temperature preparation of a noble metal alloy

    DOEpatents

    Even, Jr., William R.

    2002-01-01

    A method for producing fine, essentially contamination free, noble metal alloys is disclosed. The alloys comprise particles in a size range of 5 to 500 nm. The method comprises 1. A method for preparing a noble metal alloy at low temperature, the method comprising the steps of forming solution of organometallic compounds by dissolving the compounds into a quantity of a compatible solvent medium capable of solvating the organometallic, mixing a portion of each solution to provide a desired molarity ratio of ions in the mixed solution, adding a support material, rapidly quenching droplets of the mixed solution to initiate a solute-solvent phase separation as the solvent freezes, removing said liquid cryogen, collecting and freezing drying the frozen droplets to produce a dry powder, and finally reducing the powder to a metal by flowing dry hydrogen over the powder while warming the powder to a temperature of about 150.degree. C.

  10. Resonance ionization spectroscopy: counting noble-gas atoms

    SciTech Connect

    Hurst, G.S.; Payne, M.G.; Chen, C.H.; Willis, R.D.; Lehmann, B.E.; Kramer, S.D.

    1981-06-01

    New work on the counting of noble gas atoms, using lasers for the selective ionization and detectors for counting individual particles (electrons or positive ions) is reported. When positive ions are counted, various kinds of mass analyzers (magnetic, quadrupole, or time-of-flight) can be incorporated to provide A selectivity. It is shown that a variety of interesting and important applications can be made with atom-counting techniques which are both atomic number (Z) and mass number (A) selective.

  11. Low-field MRI of laser polarized noble gas

    NASA Technical Reports Server (NTRS)

    Tseng, C. H.; Wong, G. P.; Pomeroy, V. R.; Mair, R. W.; Hinton, D. P.; Hoffmann, D.; Stoner, R. E.; Hersman, F. W.; Cory, D. G.; Walsworth, R. L.

    1998-01-01

    NMR images of laser polarized 3He gas were obtained at 21 G using a simple, homebuilt instrument. At such low fields magnetic resonance imaging (MRI) of thermally polarized samples (e.g., water) is not practical. Low-field noble gas MRI has novel scientific, engineering, and medical applications. Examples include portable systems for diagnosis of lung disease, as well as imaging of voids in porous media and within metallic systems.

  12. 46 CFR 194.15-17 - Compressed gases other than inert gases.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Compressed gases other than inert gases. 194.15-17... Scientific Laboratory § 194.15-17 Compressed gases other than inert gases. (a) When, in consideration for a particular operation, compressed gases are needed within the laboratory, the cylinders may be...

  13. 46 CFR 194.15-17 - Compressed gases other than inert gases.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Compressed gases other than inert gases. 194.15-17... Scientific Laboratory § 194.15-17 Compressed gases other than inert gases. (a) When, in consideration for a particular operation, compressed gases are needed within the laboratory, the cylinders may be...

  14. 46 CFR 194.15-17 - Compressed gases other than inert gases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Compressed gases other than inert gases. 194.15-17... Scientific Laboratory § 194.15-17 Compressed gases other than inert gases. (a) When, in consideration for a particular operation, compressed gases are needed within the laboratory, the cylinders may be...

  15. Possible solar noble-gas component in Hawaiian basalts

    USGS Publications Warehouse

    Honda, M.; McDougall, I.; Patterson, D.B.; Doulgeris, A.; Clague, D.A.

    1991-01-01

    THE noble-gas elemental and isotopic composition in the Earth is significantly different from that of the present atmosphere, and provides an important clue to the origin and history of the Earth and its atmosphere. Possible candidates for the noble-gas composition of the primordial Earth include a solar-like component, a planetary-like component (as observed in primitive meteorites) and a component similar in composition to the present atmosphere. In an attempt to identify the contributions of such components, we have measured isotope ratios of helium and neon in fresh basaltic glasses dredged from Loihi seamount and the East Rift Zone of Kilauea1-3. We find a systematic enrichment in 20Ne and 21Ne relative to 22Ne, compared with atmospheric neon. The helium and neon isotope signatures observed in our samples can be explained by mixing of solar, present atmospheric, radiogenic and nucleogenic components. These data suggest that the noble-gas isotopic composition of the mantle source of the Hawaiian plume is different from that of the present atmosphere, and that it includes a significant solar-like component. We infer that this component was acquired during the formation of the Earth.

  16. Cucurbit[6]uril: A Possible Host for Noble Gas Atoms.

    PubMed

    Pan, Sudip; Mandal, Subhajit; Chattaraj, Pratim K

    2015-08-27

    Density functional and ab initio molecular dynamics studies are carried out to investigate the stability of noble gas encapsulated cucurbit[6]uril (CB[6]) systems. Interaction energy, dissociation energy and dissociation enthalpy are calculated to understand the efficacy of CB[6] in encapsulating noble gas atoms. CB[6] could encapsulate up to three Ne atoms having dissociation energy (zero-point energy corrected) in the range of 3.4-4.1 kcal/mol, whereas due to larger size, only one Ar or Kr atom encapsulated analogues would be viable. The dissociation energy value for the second Ar atom is only 1.0 kcal/mol. On the other hand, the same for the second Kr is -0.5 kcal/mol, implying the instability of the system. The noble gas dissociation processes are endothermic in nature, which increases gradually along Ne to Kr. Kr encapsulated analogue is found to be viable at room temperature. However, low temperature is needed for Ne and Ar encapsulated analogues. The temperature-pressure phase diagram highlights the region in which association and dissociation processes of Kr@CB[6] would be favorable. At ambient temperature and pressure, CB[6] may be used as an effective noble gas carrier. Wiberg bond indices, noncovalent interaction indices, electron density, and energy decomposition analyses are used to explore the nature of interaction between noble gas atoms and CB[6]. Dispersion interaction is found to be the most important term in the attraction energy. Ne and Ar atoms in one Ng entrapped analogue are found to stay inside the cavity of CB[6] throughout the simulation at 298 K. However, during simulation Ng2 units in Ng2@CB[6] flip toward the open faces of CB[6]. After 1 ps, one Ne atom of Ne3@CB[6] almost reaches the open face keeping other two Ne atoms inside. At lower temperature (77 K), all the Ng atoms in Ngn@CB[6] remain well inside the cavity of CB[6] throughout the simulation time (1 ps).

  17. Electrochemical Synthesis of Nanostructured Noble Metal Films for Biosensing

    NASA Astrophysics Data System (ADS)

    Bhattarai, Jay K.

    Nanostructures of noble metals (gold and silver) are of interest because of their important intrinsic properties. Noble metals by themselves are physically robust, chemically inert, highly conductive, and possess the capability to form strong bonds with thiols or dithiol molecules present in organic compounds, creating self-assembled monolayers with tunable functional groups at exposed interfaces. However, when the nanostructures are formed, they in addition possess high surface area and unique optical properties which can be tuned by adjusting the shape and the size of the nanostructures. All of these properties make nanostructures of noble metals suitable candidates to be used as a transducer for optical and electrochemical biosensing. Individual nanostructures might be easier to prepare but difficult to handle to use as a transducer. Therefore, we prepared and analyzed nanostructured films/coating of noble metals and used them as a transducer for optical and electrochemical biosensing. We have electrochemically prepared nanoporous gold (NPG) on gold wire varying different dependable parameters (deposition potential, time, and compositional ratio) to obtain an optimal structure in term of stability, morphology, and better surface area. NPG prepared using a deposition potential of --1.0 V for 10 min from 30:70% 50 mM potassium dicyanoaurate(I) and 50 mM potassium dicyanoargentate(I) was used as an optimal surface for protein immobilization, and to perform square wave voltammetry (SWV) based enzyme-linked lectinsorbent assays. On flat gold surfaces, adjacent protein molecules sterically block their active sites due to high-density packing, which can be minimized using NPG as a substrate. NPG can also show significant peak current in SWV experiments, a sensitive electrochemical technique that minimizes non-Faradaic current, which is difficult to obtain using a flat gold surface. These all make NPG a suitable substrate, electrode, and transducer to be used in

  18. Method for detecting toxic gases

    DOEpatents

    Stetter, Joseph R.; Zaromb, Solomon; Findlay, Jr., Melvin W.

    1991-01-01

    A method capable of detecting low concentrations of a pollutant or other component in air or other gas, utilizing a combination of a heating filament having a catalytic surface of a noble metal for exposure to the gas and producing a derivative chemical product from the component, and an electrochemical sensor responsive to the derivative chemical product for providing a signal indicative of the product. At concentrations in the order of about 1-100 ppm of tetrachloroethylene, neither the heating filament nor the electrochemical sensor is individually capable of sensing the pollutant. In the combination, the heating filament converts the benzyl chloride to one or more derivative chemical products which may be detected by the electrochemical sensor.

  19. Method for detecting toxic gases

    DOEpatents

    Stetter, J.R.; Zaromb, S.; Findlay, M.W. Jr.

    1991-10-08

    A method is disclosed which is capable of detecting low concentrations of a pollutant or other component in air or other gas. This method utilizes a combination of a heating filament having a catalytic surface of a noble metal for exposure to the gas and producing a derivative chemical product from the component. An electrochemical sensor responds to the derivative chemical product for providing a signal indicative of the product. At concentrations in the order of about 1-100 ppm of tetrachloroethylene, neither the heating filament nor the electrochemical sensor is individually capable of sensing the pollutant. In the combination, the heating filament converts the benzyl chloride to one or more derivative chemical products which may be detected by the electrochemical sensor. 6 figures.

  20. Indigenous nitrogen in the Moon: Constraints from coupled nitrogen-noble gas analyses of mare basalts

    NASA Astrophysics Data System (ADS)

    Füri, Evelyn; Barry, Peter H.; Taylor, Lawrence A.; Marty, Bernard

    2015-12-01

    Nitrogen and noble gas (Ne-Ar) abundances and isotope ratios, determined by step-wise CO2 laser-extraction, static-mass spectrometry analysis, are reported for bulk fragments and mineral separates of ten lunar mare basalts (10020, 10057, 12008, 14053, 15555, 70255, 71557, 71576, 74255, 74275), one highland breccia (14321), and one ferroan anorthosite (15414). The mare basalt sub-samples 10057,183 and 71576,12 contain a large amount of solar noble gases, whereas neon and argon in all other samples are purely cosmogenic, as shown by their 21Ne/22Ne ratios of ≈0.85 and 36Ar/38Ar ratios of ≈0.65. The solar-gas-free basalts contain a two-component mixture of cosmogenic 15N and indigenous nitrogen (<0.5 ppm). Mare basalt 74255 and the olivine fraction of 15555,876 record the smallest proportion of 15Ncosm; therefore, their δ15 N values of -0.2 to + 26.7 ‰ (observed at the low-temperature steps) are thought to well represent the isotopic composition of indigenous lunar nitrogen. However, δ15 N values ≤ - 30 ‰ are found in several basalts, overlapping with the isotopic signature of Earth's primordial mantle or an enstatite chondrite-like impactor. While the lowest δ15 N values allow for nitrogen trapped in the Moon's interior to be inherited from the proto-Earth and/or the impactor, the more 15N-enriched compositions require that carbonaceous chondrites provided nitrogen to the lunar magma ocean prior to the solidification of the crust. Since nitrogen can efficiently be incorporated into mafic minerals (olivine, pyroxene) under oxygen fugacities close to or below the iron-wustite buffer (Li et al., 2013), the mare basalt source region is likely characterized by a high nitrogen storage capacity. In contrast, anorthosite 15414 shows no traces of indigenous nitrogen, suggesting that nitrogen was not efficiently incorporated into the lunar crust during magma ocean differentiation.

  1. Hydrochemistry and noble gas origin of geothermal waters of Icheon and Pocheon area in South Korea

    NASA Astrophysics Data System (ADS)

    Jeong, Chan Ho; Shin, Seon Ho; Nagao, Keisuke; Kim, Kyu Han; Koh, Yung Kwon; Kim, Gun Young

    2010-05-01

    Hydrochemical, stable isotopic (δ18O and δD) and noble gas isotopic analyses of seven geothermal water samples, eleven groundwater samples and six surface water samples collected from the Icheon and Pocheon area were carried out to find out hydrochemical characteristics, and to interpret the source of noble gases and the geochemical evolution of the geothermal waters. The geothermal waters show low temperature type ranging from 21.5 to 31.4 ℃ and the pH value between 6.69 and 9.21. Electrical conductivity of geothermal waters has the range from 310 to 735 μS/cm. Whereas the geothermal in the Icheon area shows the geochemical characteristics of neutral pH, the Ca-HCO3(or Ca(Na)-HCO3) chemical type and a high uranium content, the geothermal water in the Pocheon area shows the characteristics of alkaline pH, the Na-HCO3 chemical type and a high fluorine content. These characteristics indicate that the geothermal water in the Icheon area is under the early stage in the geochemical evolution, and that geothermal water in the Pocheon area has been geochemically evolved. The δ18O and δD values of geothermal waters show the range of -10.1˜-8.69‰ and from -72.2˜-60.8‰, respectively, and these values supply the information of the recharge area of geothermal waters. The 3He/4He ratios of the geothermal waters range from 0.09×10-6 to 0.65×10-6 which are plotted above the mixing line between air and crustal components. Whereas the helium gas in the Icheon geothermal water was mainly provided from the atmospheric source mixing with the mantle(or magma) origin, the origin of helium gas in the Pocheon geothermal water shows a dominant crustal source. 40Ar/36Ar ratios of geothermal water are in the range of an atmosphere source. Key words: hot spring water, hydrochemical composition, low temperature type, 3He/4He ratios, crustal source

  2. Permeability of cork to gases.

    PubMed

    Faria, David P; Fonseca, Ana L; Pereira, Helen; Teodoro, Orlando M N D

    2011-04-27

    The permeability of gases through uncompressed cork was investigated. More than 100 samples were assessed from different plank qualities to provide a picture of the permeability distribution. A novel technique based on a mass spectrometer leak detector was used to directly measure the helium flow through the central area of small disks 10 mm in diameter and 2 mm thick. The permeability for nitrogen, oxygen, and other gases was measured by the pressure rise technique. Boiled and nonboiled cork samples from different sections were evaluated. An asymmetric frequency distribution ranging 3 orders of magnitude (roughly from 1 to 1000 μmol/(cm·atm·day)) for selected samples without macroscopic defects was found, having a peak below 100 μmol/(cm·atm·day). Correlation was found between density and permeability: higher density samples tend to show lower permeability. However, boiled cork showed a mean lower permeability despite having a lower density. The transport mechanism of gases through cork was also examined. Calculations suggest that gases permeate uncompressed cork mainly through small channels between cells under a molecular flow regime. The diameter of such channels was estimated to be in the range of 100 nm, in agreement with the plasmodesmata size in the cork cell walls.

  3. Hydrophobic encapsulation of hydrocarbon gases.

    PubMed

    Leontiev, Alexander V; Saleh, Anas W; Rudkevich, Dmitry M

    2007-04-26

    [reaction: see text] Encapsulation data for hydrophobic hydrocarbon gases within a water-soluble hemicarcerand in aqueous solution are reported. It is concluded that hydrophobic interactions serve as the primary driving force for the encapsulation, which can be used for the design of gas-separating polymers with intrinsic inner cavities.

  4. Interaction quenches of Fermi gases

    SciTech Connect

    Uhrig, Goetz S.

    2009-12-15

    It is shown that the jump in the momentum distribution of Fermi gases evolves smoothly for small and intermediate times once an interaction between the fermions is suddenly switched on. The jump does not vanish abruptly. The loci in momentum space where the jumps occur are those of the noninteracting Fermi sea. No relaxation of the Fermi surface geometry takes place.

  5. Transport of methane and noble gases during gas push-pull tests in variably saturated porous media.

    PubMed

    Gómez, Katherine; Gonzalez-Gil, Graciela; Schroth, Martin H; Zeyer, Josef

    2008-04-01

    The gas push-pull test (GPPT) is a single-well gas-tracer method to quantify in situ rates of CH4 oxidation in soils. To improve the design and interpretation of GPPT field experiments, gas component transport during GPPTs was examined in abiotic porous media over a range of water saturations (0.0 < or = Sw < or = 0.61). A series of GPPTs using He, Ne, and Ar as tracers for CH4 were performed at two injection/extraction gas flow rates (approximately 200 and approximately 700 mL min(-1)) in a laboratory tank. Extraction phase breakthrough curves and mass recovery curves of the gaseous components became more similar at higher Sw as water in the pore space restricted diffusive gas-phase transport. Diffusional fractionation of the stable carbon isotopes of CH4 during the extraction period of GPPTs also decreased with increasing Sw (particularly when Sw > 0.42). Gas-component transport during GPPTs was numerically simulated using estimated hydraulic parameters for the porous media and no fitting of data for the GPPTs. Numerical simulations accurately predicted the relative decline of the gaseous components in the breakthrough curves, but slightly overestimated recoveries at low Sw (< or = 0.35) and underestimated recoveries at high Sw (> or = 0.49). Comparison of numerical simulations considering and not considering air-water partitioning indicated that removal of gaseous components through dissolution in pore water was not significant during GPPTs, even at Sw = 0.61. These data indicate that Ar is a good tracer for CH4 physical transport over the full range of Sw studied, whereas, at Sw > 0.61, any of the tracers could be used. Greater mass recovery at higher Sw raises the possibility to reduce gas flow rates, thereby extending GPPT times in environments such as tundra soils where low activity due to low temperatures may require longer test times to establish a quantifiable difference between reactant and tracer breakthrough curves.

  6. Adsorption and desorption of noble gases on activated charcoal: II. sup 222 Rn studies in a monolayer and packed bed

    SciTech Connect

    Scarpitta, S.C.; Harley, N.H. )

    1990-10-01

    The adsorptive and desorptive characteristics of canisters containing a petroleum-based charcoal were investigated under controlled conditions of temperature, relative humidity, and Rn concentration. Charcoals exposed in a monolayer and packed bed during exposure intervals of 1-7 d demonstrate that Rn adsorption and desorption are dependent on bed depth and the amount of water adsorbed. Changes in the adsorptive and desorptive properties of the charcoal occurred near the break-point where the pores became occluded by water vapor that condenses in the entrance capillaries. Radon-222 adsorption is decreased by an order of magnitude as the amount of adsorbed water exceeds the break-point of the charcoal. The reduction in pore surface due to adsorbed water results in a marked increase in the rate of Rn loss from exposed canisters, accounting for reduced adsorption. The apparent desorption time-constant for a 2-cm bed of loose Witco 6 x 10 mesh charcoal containing 0.220-0.365 kg H{sub 2}O kg-1 is typically between 2-8 h. The apparent desorption time-constant for an equivalent packed bed containing a water vapor content of 0.026-0.060 kg H{sub 2}O kg-1, which is below the break-point of the charcoal, is about 15-30 h. Conventional charcoal canisters, if exposed in the fully-opened configuration, can achieve the break-point in less than 4 d at 70% humidity. The use of a diffusion barrier would allow for longer exposure times until the break-point of the charcoal is achieved.

  7. Dissolved noble gases and stable isotopes as tracers of preferential fluid flow along faults in the Lower Rhine Embayment, Germany

    NASA Astrophysics Data System (ADS)

    Gumm, L. P.; Bense, V. F.; Dennis, P. F.; Hiscock, K. M.; Cremer, N.; Simon, S.

    2016-02-01

    Groundwater in shallow unconsolidated sedimentary aquifers close to the Bornheim fault in the Lower Rhine Embayment (LRE), Germany, has relatively low δ2H and δ18O values in comparison to regional modern groundwater recharge, and 4He concentrations up to 1.7 × 10-4 cm3 (STP) g-1 ± 2.2 % which is approximately four orders of magnitude higher than expected due to solubility equilibrium with the atmosphere. Groundwater age dating based on estimated in situ production and terrigenic flux of helium provides a groundwater residence time of ˜107 years. Although fluid exchange between the deep basal aquifer system and the upper aquifer layers is generally impeded by confining clay layers and lignite, this study's geochemical data suggest, for the first time, that deep circulating fluids penetrate shallow aquifers in the locality of fault zones, implying that sub-vertical fluid flow occurs along faults in the LRE. However, large hydraulic-head gradients observed across many faults suggest that they act as barriers to lateral groundwater flow. Therefore, the geochemical data reported here also substantiate a conduit-barrier model of fault-zone hydrogeology in unconsolidated sedimentary deposits, as well as corroborating the concept that faults in unconsolidated aquifer systems can act as loci for hydraulic connectivity between deep and shallow aquifers. The implications of fluid flow along faults in sedimentary basins worldwide are far reaching and of particular concern for carbon capture and storage (CCS) programmes, impacts of deep shale gas recovery for shallow groundwater aquifers, and nuclear waste storage sites where fault zones could act as potential leakage pathways for hazardous fluids.

  8. Detection of soft X-rays and a sensitive search for noble gases in comet Hale-Bopp.

    PubMed

    Krasnopolsky, V A; Mumma, M J; Abbott, M; Flynn, B C; Meech, K J; Yeomans, D K; Feldman, P D; Cosmovici, C B

    1997-09-05

    An image of comet Hale-Bopp (C/1995 O1) in soft x-rays reveals a central emission offset from the nucleus, as well as an extended emission feature that does not correlate with the dust jets seen at optical wavelengths. Neon was found to be depleted in the cometary ice by more than a factor of 25 relative to solar abundance, which suggests that ices in Hale-Bopp formed at (or later experienced) temperatures higher than 25 kelvin. A helium line emission at a wavelength of 584 angstroms was detected and may be attributable to charge transfer of solar wind alpha particles in the cometary coma. Ionized oxygen and another helium line contribute to an emission observed at 538 angstroms.

  9. Compression behaviors of binary skutterudite CoP3 in noble gases up to 40 GPa at room temperature.

    PubMed

    Niwa, Ken; Nomichi, Daisuke; Hasegawa, Masashi; Okada, Taku; Yagi, Takehiko; Kikegawa, Takumi

    2011-04-18

    The binary skutterudite CoP(3) has a large void at the body-centered site of each cubic unit cell and is, therefore, called a nonfilled skutterudite. We investigated its room-temperature compression behavior up to 40.4 GPa in helium and argon using a diamond-anvil cell. High-pressure in situ X-ray diffraction and Raman scattering measurements found no phase transition and a stable cubic structure up to the maximum pressure in both media. A fitting of the present pressure-volume data to the third-order Birch-Murnaghan equation of state yields a zero-pressure bulk modulus K(0) of 147(3) GPa [pressure derivative K(0)' of 4.4(2)] and 171(5) GPa [where K(0)' = 4.2(4)] in helium and argon, respectively. The Grüneisen parameter was determined to be 1.4 from the Raman scattering measurements. Thus, CoP(3) is stiffer than other binary skutterudites and could therefore be used as a host cage to accommodate large atoms under high pressure without structural collapse.

  10. Noble Metals and Spinel Settling in High Level Waste Glass Melters

    SciTech Connect

    Sundaram, S. K.; Perez, Joseph M.

    2000-09-30

    In the continuing effort to support the Defense Waste Processing Facility (DWPF), the noble metals issue is addressed. There is an additional concern about the amount of noble metals expected to be present in the future batches that will be considered for vitrification in the DWPF. Several laboratory, as well as melter-scale, studies have been completed by various organizations (mainly PNNL, SRTC, and WVDP in the USA). This letter report statuses the noble metals issue and focuses at the settling of noble metals in melters.

  11. Inert anode containing base metal and noble metal useful for the electrolytic production of aluminum

    DOEpatents

    Ray, Siba P.; Liu, Xinghua

    2000-01-01

    An inert anode for production of metals such as aluminum is disclosed. The inert anode comprises a base metal selected from Cu and Ag, and at least one noble metal selected from Ag, Pd, Pt, Au, Rh, Ru, Ir and Os. The inert anode may optionally be formed of sintered particles having interior portions containing more base metal than noble metal and exterior portions containing more noble metal than base metal. In a preferred embodiment, the base metal comprises Cu, and the noble metal comprises Ag, Pd or a combination thereof.

  12. EDITORIAL: Cold Quantum GasesEditorial: Cold Quantum Gases

    NASA Astrophysics Data System (ADS)

    Vassen, W.; Hemmerich, A.; Arimondo, E.

    2003-04-01

    This Special Issue of Journal of Optics B: Quantum and Semiclassical Optics brings together the contributions of various researchers working on theoretical and experimental aspects of cold quantum gases. Different aspects of atom optics, matter wave interferometry, laser manipulation of atoms and molecules, and production of very cold and degenerate gases are presented. The variety of subjects demonstrates the steadily expanding role associated with this research area. The topics discussed in this issue, extending from basic physics to applications of atom optics and of cold atomic samples, include: bulletBose--Einstein condensation bulletFermi degenerate gases bulletCharacterization and manipulation of quantum gases bulletCoherent and nonlinear cold matter wave optics bulletNew schemes for laser cooling bulletCoherent cold molecular gases bulletUltra-precise atomic clocks bulletApplications of cold quantum gases to metrology and spectroscopy bulletApplications of cold quantum gases to quantum computing bulletNanoprobes and nanolithography. This special issue is published in connection with the 7th International Workshop on Atom Optics and Interferometry, held in Lunteren, The Netherlands, from 28 September to 2 October 2002. This was the last in a series of Workshops organized with the support of the European Community that have greatly contributed to progress in this area. The scientific part of the Workshop was managed by A Hemmerich, W Hogervorst, W Vassen and J T M Walraven, with input from members of the International Programme Committee who are listed below. The practical aspects of the organization were ably handled by Petra de Gijsel from the Vrije Universiteit in Amsterdam. The Workshop was funded by the European Science Foundation (programme BEC2000+), the European Networks 'Cold Quantum Gases (CQG)', coordinated by E Arimondo, and 'Cold Atoms and Ultraprecise Atomic Clocks (CAUAC)', coordinated by J Henningsen, by the German Physical Society (DFG), by

  13. Measuring the Noble Metal and Iodine Composition of Extracted Noble Metal Phase from Spent Nuclear Fuel Using Instrumental Neutron Activation Analysis

    SciTech Connect

    Palomares, R. I.; Dayman, Kenneth J.; Landsberger, Sheldon; Biegalski, Steven R.; Soderquist, Chuck Z.; Casella, Amanda J.; Brady Raap, Michaele C.; Schwantes, Jon M.

    2015-04-01

    Mass quantities of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis (NAA). Nuclide presence is predicted using fission yield analysis, and mass quantification is derived from standard gamma spectroscopy and radionuclide decay analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO2 fuel dissolved in nitric acid and UO2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared. Lastly, the implications of the rapid analytic speed of instrumental NAA are discussed in relation to potential nuclear forensics applications.

  14. Cross-Calibration of Secondary Electron Multiplier in Noble Gas Analysis

    NASA Astrophysics Data System (ADS)

    Santato, Alessandro; Hamilton, Doug; Deerberg, Michael; Wijbrans, Jan; Kuiper, Klaudia; Bouman, Claudia

    2015-04-01

    case the known isotopic ratio is measured on different pairs of detectors and the true value of the isotopic ratio of interest can be determined by a specific equation. In noble gas analysis, due to the decay of the ion beam during the measurement as well as the special isotopic systematic of the gases themselves, the cross-calibration of the SEM using these techniques becomes more complex and other methods should be investigated. In this work we present a comparison between different approaches to cross-calibrate multiple SEM's in noble gas analysis in order to evaluate the most suitable and reliable method. References: [1] Mark et al. (2009) Geochem. Geophys. Geosyst. 10, 1-9. [2] Mark et al. (2011) Geochim. Cosmochim. 75, 7494-7501. [3] Phillips and Matchan (2013) Geochimica et Cosmochimica Acta 121, 229-239. [4] Koornneef et al. (2014) Journal of Analytical Atomic Spectrometry 28, 749-754.

  15. Noble metal nanoparticles: Optical forces, electrochemical Ostwald ripening, and photovoltage

    NASA Astrophysics Data System (ADS)

    Redmond, Peter

    This thesis describes three distinct aspects of the chemical properties of noble metal nanoparticles. The first chapter introduces the surface plasmon resonance of noble metal nanoparticles. The second chapter presents an electrodynamic model for the calculation of the attractive optical forces that arise when two dielectric particles are irradiated in a light field. These forces show resonances at dipolar plasmon wavelengths, similar to resonances in the near-field electromagnetic intensities. At MW/cm2 intensities, optical forces can be stronger than van der Waals forces. The third chapter investigates the size dependent electrochemical properties of silver nanoparticles. These thermally evaporated silver nanoparticles spontaneously evolve in size when immersed in pure water on conducting substrates. The process is understood through an electrochemical Ostwald ripening mechanism driven by the size dependence of the work function and standard electrode potential. The fourth and fifth chapters consider photo-induced surface reactivity of noble metal particles. First, in the fourth chapter, the light driven deposition of copper onto gold nanoparticle electrodes is presented. The photocurrent is a nonlinear function of laser intensity and increases sharply with cathodic voltage in the underpotential deposition region. The photoreduction is attributed to laser heating (caused by decay of the plasmon oscillation) of the Au nanoparticles, rather than "hot electron" processes. Secondly, in the fifth chapter, the photo-induced oxidation of citrate is studied on silver nanoparticle electrodes. Irradiation of the citrate coated particles is shown to cause the particles to charge negatively from the irreversible transfer of electrons from citrate to the particles. It is hypothesized that the particle plasmon oscillation decays into electron hole pair(s) that causes the photo-oxidation of the surface bound citrate. Both the gold and silver particle systems are simulated using

  16. Catalytic reforming using group VIII noble metal high silica faujasites

    SciTech Connect

    Vaughan, D.E.; Ghosh, A.K

    1989-05-23

    A process is described for reforming a naphtha feed stock utilizing a catalytic faujasite zeolite composition, which comprises contacting the feed stock at reforming conditions and in the presence of hydrogen with the catalytic zeolite having a faujasite structure and having a SiO/sub 2//Al/sub 2/O/sub 3/ ratio between about 10 and 80 and containing a Group VIII noble metal dispersed therein so as to have a dispersion of hydrogen to metal of about 0.1 to 1, as measured by hydrogen chemisorption.

  17. Mechanical response of noble gas films to an oscillating substrate

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hajime; Taniguchi, Junko; Suzuki, Masaru; Miura, Kouji; Arakawa, Ichiro

    2012-12-01

    We carried out quartz-crystal microbalance (QCM) experiments for Xe films adsorbed on an exfoliated single-crystalline graphite substrate (Xe/Gr) and Kr 1ms adsorbed on a synthetic mica substrate (Kr/mica) around LN2 temperature. For Xe/Gr, it was found that the resonance frequency decreases greatly around the first layer completion, while it does not decrease at low coverages. The observed behavior is similar to that of Kr films on a graphite substrate (Kr/Gr). This demonstrates that the layer completion strongly affects the sliding motion of noble gas films on graphite.

  18. Isotopic Analysis and Evolved Gases

    NASA Technical Reports Server (NTRS)

    Swindle, Timothy D.; Boynton, William V.; Chutjian, Ara; Hoffman, John H.; Jordan, Jim L.; Kargel, Jeffrey S.; McEntire, Richard W.; Nyquist, Larry

    1996-01-01

    Precise measurements of the chemical, elemental, and isotopic composition of planetary surface material and gases, and observed variations in these compositions, can contribute significantly to our knowledge of the source(s), ages, and evolution of solar system materials. The analyses discussed in this paper are mostly made by mass spectrometers or some other type of mass analyzer, and address three broad areas of interest: (1) atmospheric composition - isotopic, elemental, and molecular, (2) gases evolved from solids, and (3) solids. Current isotopic data on nine elements, mostly from in situ analysis, but also from meteorites and telescopic observations are summarized. Potential instruments for isotopic analysis of lunar, Martian, Venusian, Mercury, and Pluto surfaces, along with asteroid, cometary and icy satellites, surfaces are discussed.

  19. Extended thermodynamics of dense gases

    NASA Astrophysics Data System (ADS)

    Arima, T.; Taniguchi, S.; Ruggeri, T.; Sugiyama, M.

    2012-11-01

    We study extended thermodynamics of dense gases by adopting the system of field equations with a different hierarchy structure to that adopted in the previous works. It is the theory of 14 fields of mass density, velocity, temperature, viscous stress, dynamic pressure, and heat flux. As a result, most of the constitutive equations can be determined explicitly by the caloric and thermal equations of state. It is shown that the rarefied-gas limit of the theory is consistent with the kinetic theory of gases. We also analyze three physically important systems, that is, a gas with the virial equations of state, a hard-sphere system, and a van der Waals fluid, by using the general theory developed in the former part of the present work.

  20. Annihilation in Gases and Galaxies

    NASA Technical Reports Server (NTRS)

    Drachman, Richard J. (Editor)

    1990-01-01

    This publication contains most of the papers, both invited and contributed, that were presented at the Workshop of Annihilation in Gases and Galaxies. This was the fifth in a biennial series associated with the International Conference on the Physics of Electronic and Atomic Collisions. Subjects covered included the scattering and annihilation of positrons and positronium atoms in various media, including those of astrophysical interest. In addition, the topics of antimatter and dark matter were covered.

  1. Theoretical Insight into Shocked Gases

    SciTech Connect

    Leiding, Jeffery Allen

    2016-09-29

    I present the results of statistical mechanical calculations on shocked molecular gases. This work provides insight into the general behavior of shock Hugoniots of gas phase molecular targets with varying initial pressures. The dissociation behavior of the molecules is emphasized. Impedance matching calculations are performed to determine the maximum degree of dissociation accessible for a given flyer velocity as a function of initial gas pressure.

  2. 46 CFR 147.60 - Compressed gases.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Compressed gases. 147.60 Section 147.60 Shipping COAST... Other Special Requirements for Particular Materials § 147.60 Compressed gases. (a) Cylinder requirements. Cylinders used for containing hazardous ships' stores that are compressed gases must be— (1) Authorized...

  3. 46 CFR 147.60 - Compressed gases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Compressed gases. 147.60 Section 147.60 Shipping COAST... Other Special Requirements for Particular Materials § 147.60 Compressed gases. (a) Cylinder requirements. Cylinders used for containing hazardous ships' stores that are compressed gases must be— (1) Authorized...

  4. 46 CFR 147.60 - Compressed gases.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Compressed gases. 147.60 Section 147.60 Shipping COAST... Other Special Requirements for Particular Materials § 147.60 Compressed gases. (a) Cylinder requirements. Cylinders used for containing hazardous ships' stores that are compressed gases must be— (1) Authorized...

  5. 40 CFR 1065.750 - Analytical gases.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Analytical gases. 1065.750 Section 1065.750 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... § 1065.750 Analytical gases. Analytical gases must meet the accuracy and purity specifications of...

  6. 40 CFR 1065.750 - Analytical gases.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Analytical gases. 1065.750 Section 1065.750 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... § 1065.750 Analytical gases. Analytical gases must meet the accuracy and purity specifications of...

  7. 40 CFR 1065.750 - Analytical gases.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Analytical gases. 1065.750 Section 1065.750 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... § 1065.750 Analytical gases. Analytical gases must meet the accuracy and purity specifications of...

  8. 40 CFR 92.112 - Analytical gases.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Analytical gases. 92.112 Section 92.112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.112 Analytical gases. (a) Gases...

  9. 40 CFR 89.312 - Analytical gases.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Analytical gases. 89.312 Section 89.312 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF....312 Analytical gases. (a) The shelf life of all calibration gases must not be exceeded. The...

  10. 40 CFR 89.312 - Analytical gases.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Analytical gases. 89.312 Section 89.312 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Provisions § 89.312 Analytical gases. (a) The shelf life of all calibration gases must not be exceeded....

  11. Greenhouse Gases Monitoring from Space

    NASA Astrophysics Data System (ADS)

    Moriyama, Takashi

    The role of greenhouse gases in global warming processes and an important element of the global carbon cycle is widely recognized. With the advent of the technical means to provide new monitoring and measurement of greenhouse gases (GHG) from space, JAXA has identified the coordination of these measurements and their application by cooperating with international space agencies. In order to foster the use of space-based GHG observations and consolidate data requirements for the next generation GHG monitoring mission from space, a synergetic strategy for easy access to GHG satellite observations, including GOSAT (Greenhouse Gases Monitoring Satellite, JAXA) and current observations should be developed, and also harmonizing the next generation of GHG satellite observations shoud be facilitated. The Paper describes the current status of international activities of GHG monitoring from space and relations with policy makers and stake holders. The long term GHG monitoring from space is also proposed by respecting the GEO Carbon Strategy which is published in March 2010. Also, GOSAT sample XCO2 and XCH4 global column amount datasets will be introduced with the avtivities of validation campaign.

  12. Evaluating Gas-Phase Transport And Detection Of Noble Gas Signals From Underground Nuclear Explosions Using Chemical Tracers

    NASA Astrophysics Data System (ADS)

    Carrigan, C. R.; Hunter, S. L.; Sun, Y.; Wagoner, J. L.; Ruddle, D.; Anderson, G.; Felske, D.; Myers, K.; Zucca, J. J.; Emer, D. F.; Townsend, M.; Drellack, S.; Chipman, V.; Snelson, C. M.

    2013-12-01

    The 1993 Non-Proliferation Experiment (NPE) involved detonating 1 kiloton of chemical explosive in a subsurface cavity which also contained bottles of tracer gases (ref 1). That experiment provided an improved understanding of transport processes relevant to the detection of noble gas signals at the surface emanating from a clandestine underground nuclear explosion (UNE). As an alternative to performing large chemical detonations to simulate gas transport from UNEs, we have developed a test bed for subsurface gas transport, sampling and detection studies using a former UNE cavity. The test bed site allows for the opportunity to evaluate pathways to the surface created by the UNE as well as possible transport mechanisms including barometric pumping and cavity pressurization (ref 2). With the test bed we have monitored long-term chemical tracers as well as newly injected tracers. In order to perform high temporal resolution tracer gas monitoring, we have also developed a Subsurface Gas Smart Sampler (SGSS) which has application during an actual On Site Inspection (OSI) and is available for deployment in OSI field exercises planned for 2014. Deployment of five SGSS at the remote test bed has provided unparalleled detail concerning relationships involving tracer gas transport to the surface, barometric fluctuations and temporal variations in the natural radon concentration. We anticipate that the results of our tracer experiments will continue to support the development of improved noble gas detection technology for both OSI and International Monitoring System applications. 1. C.R. Carrigan et al., 1996, Nature, 382, p. 528. 2. Y. Sun and C.R. Carrigan, 2012, Pure Appl. Geophys., DOI 10.1007/s00024-012-0514-4.

  13. Solubility controlled noble gas fractionation during magmatic degassing: Implications for noble gas compositions of primary melts of OIB and MORB

    NASA Astrophysics Data System (ADS)

    Yamamoto, Junji; Burnard, Pete G.

    2005-02-01

    Noble gas abundances in basaltic glasses from ocean islands (OIBs) are generally lower than those of mid-oceanic ridge basalts (MORBs), contrary to most geodynamic models which usually require that the source of OIBs is less degassed (resulting in higher primordial noble gas abundances) and more trace element enriched (resulting in higher radiogenic noble gas abundances) than the MORB source. Therefore, noble gas abundances in OIBs are often thought to have been reduced by extensive gas loss from the magma before eruption. The extent of magmatic degassing can be tested as it will cause characteristic changes in the composition of the volatiles; notably the 4He/ 40Ar* ratio (where 40Ar* is 40Ar corrected for atmospheric contamination) will increase in residual volatiles due to the higher solubility of He relative to Ar. The degree of He-Ar fractionation for a given fraction of gas loss depends on the ratio of the solubilities, S He/S Ar, which is sensitive to (among other things) the CO 2 and H 2O content of the basalt at the time of degassing. From a global database of OIB and MORB glasses, we show that 4He/ 40Ar* ratios of MORB glasses are broadly consistent with degassing of a magma with an initial 40Ar of ≈1.5 × 10 -5 ccSTP/g, i.e., similar to that of the "popping rock." However, OIB glasses generally have lower 40Ar* concentration for a given 4He/ 40Ar*. While this would appear to require lower 40Ar* abundances in the undegassed OIB magmas, the higher volatile contents of OIBs will reduce S He/S Ar (relative to MORBs) during degassing. By modeling S He/S Ar in OIBs, it is possible to show that extensive degassing of OIBs can occur without dramatically increasing the 4He/ 40Ar* ratio. We show that undegassed 40Ar concentrations of OIB magmas were probably similar to those of MORBs.

  14. Modulation by the noble gas argon of the catalytic and thrombolytic efficiency of tissue plasminogen activator.

    PubMed

    David, Hélène N; Haelewyn, Benoît; Risso, Jean-Jacques; Abraini, Jacques H

    2013-01-01

    Argon has been shown to provide cortical as well as, under certain conditions, subcortical neuroprotection in all models so far (middle cerebral artery occlusion, trauma, neonatal asphyxia, etc.). This has led to the suggestion that argon could be a cost-efficient alternative to xenon, a metabolically inert gas thought to be gold standard in gas pharmacology but whose clinical development suffers its little availability and excessive cost of production. However, whether argon interacts with the thrombolytic agent tissue plasminogen activator, which is the only approved therapy of acute ischemic stroke to date, still remains unknown. This latter point is not trivial since previous data have clearly demonstrated the inhibiting effect of xenon on tPA enzymatic and thrombolytic efficiency and the critical importance of the time at which xenon is administered, during or after ischemia, in order not to block thrombolysis and to obtain neuroprotection. Here, we investigated the effect of argon on tPA enzymatic and thrombolytic efficiency using in vitro methods shown to provide reliable prediction of the in vivo effects of both oxygen and the noble inert gases on tPA-induced thrombolysis. We found that argon has a concentration-dependent dual effect on tPA enzymatic and thrombolytic efficiency. Low and high concentrations of argon of 25 and 75 vol% respectively block and increase tPA enzymatic and thrombolytic efficiency. The possible use of argon at low and high concentrations in the treatment of acute ischemic stroke if given during ischemia or after tPA-induced reperfusion is discussed as regards to its neuroprotectant action and its inhibiting and facilitating effects on tPA-induced thrombolysis. The mechanisms of argon-tPA interactions are also discussed.

  15. 75 FR 12737 - Applications To Export Electric Energy; Noble Energy Marketing and Trade Corp.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-17

    ... Applications To Export Electric Energy; Noble Energy Marketing and Trade Corp. AGENCY: Office of Electricity... applications, Noble Energy Marketing and Trade Corp. (NEMT) has applied for authority to transmit electric energy from the United States to Mexico and from the United States to Canada pursuant to section...

  16. RISK REDUCTION VIA GREENER SYNTHESIS OF NOBLE METAL NANOSTRUCTURES AND NANOCOMPOSITES

    EPA Science Inventory

    Aqueous preparation of nanoparticles using vitamins B2 and C which can function both as reducing and capping agents are described. Bulk and shape-controlled synthesis of noble nanostructures via microwave (MW)-assisted spontaneous reduction of noble metal salts using a-D-glucose,...

  17. David Noble's Battle to Defend the 'Sacred Space' of the Classroom.

    ERIC Educational Resources Information Center

    Young, Jeffrey R.

    2000-01-01

    Reports on the crusade of David F. Noble, a history professor at York University (Ontario), against distance education, which he sees as the latest episode in the saga of the corporatization of American higher education. Notes Noble's views on the relationship between politics and technology, intellectual property issues of courseware, and the…

  18. Noble Gas Migration Experiment to Support the Detection of Underground Nuclear Explosions

    SciTech Connect

    Olsen, Khris B.; Kirkham, Randy R.; Woods, Vincent T.; Haas, Derek A.; Hayes, James C.; Bowyer, Ted W.; Mendoza, Donaldo P.; Lowrey, Justin D.; Lukins, Craig D.; Suarez, Reynold; Humble, Paul H.; Ellefson, Mark D.; Ripplinger, Mike D.; Zhong, Lirong; Mitroshkov, Alexandre V.; Aalseth, Craig E.; Prinke, Amanda M.; Mace, Emily K.; McIntyre, Justin I.; Stewart, Timothy L.; Mackley, Rob D.; Milbrath, Brian D.; Emer, Dudley; Biegalski, S.

    2016-03-01

    A Noble Gas Migration Experiment (NGME) funded by the National Center for Nuclear Security and conducted at the Nevada National Security Site (NNSS) in collaboration with Lawrence Livermore national Laboratory and National Security Technology provided critical on-site inspection (OSI) information related to the detection of an underground nuclear explosion (UNE) event using noble gas signatures.

  19. Noble metal-free hydrogen evolution catalysts for water splitting.

    PubMed

    Zou, Xiaoxin; Zhang, Yu

    2015-08-07

    Sustainable hydrogen production is an essential prerequisite of a future hydrogen economy. Water electrolysis driven by renewable resource-derived electricity and direct solar-to-hydrogen conversion based on photochemical and photoelectrochemical water splitting are promising pathways for sustainable hydrogen production. All these techniques require, among many things, highly active noble metal-free hydrogen evolution catalysts to make the water splitting process more energy-efficient and economical. In this review, we highlight the recent research efforts toward the synthesis of noble metal-free electrocatalysts, especially at the nanoscale, and their catalytic properties for the hydrogen evolution reaction (HER). We review several important kinds of heterogeneous non-precious metal electrocatalysts, including metal sulfides, metal selenides, metal carbides, metal nitrides, metal phosphides, and heteroatom-doped nanocarbons. In the discussion, emphasis is given to the synthetic methods of these HER electrocatalysts, the strategies of performance improvement, and the structure/composition-catalytic activity relationship. We also summarize some important examples showing that non-Pt HER electrocatalysts could serve as efficient cocatalysts for promoting direct solar-to-hydrogen conversion in both photochemical and photoelectrochemical water splitting systems, when combined with suitable semiconductor photocatalysts.

  20. Interaction of the Fe + cation with heavy noble gas atoms

    NASA Astrophysics Data System (ADS)

    Heinemann, Christoph; Schwarz, Joseph; Koch, Wolfram; Schwarz, Helmut

    1995-09-01

    The diatomic iron-noble gas complexes FeAr+, FeKr+, FeXe+, and FeRn+ have been theoretically investigated by means of quantum-chemical calculations including an extensive treatment of electron correlation. Potential energy curves and spectroscopic constants for the lowest 4Δ and 6Δ states are derived from an open-shell coupled-cluster approach and the relative energies of all seven low-lying electronic states are evaluated by the multireference configuration interaction method. While in FeAr+ the lowest quartet and sextet states are found to be energetically almost degenerate, the heavier Fe+-noble gas molecules are predicted to exhibit 4Φ ground states. From a qualitative point of view bonding in these species is shown to be electrostatic in origin with intrinsically higher interaction energies for the quartet as compared to the sextet states. For calibration purposes, also an accurate calculation of the 4F(4s03d7)-6D(4s13d6) energy difference in the atomic Fe+ cation is provided.