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Sample records for dependent deuterium fractionation

  1. Deuterium fractionation mechanisms in interstellar clouds

    SciTech Connect

    Dalgarno, A.; Lepp, S.

    1984-12-01

    The theory of the fractionation of deuterated molecules is extended to include reactions with atomic deuterium. With the recognition that dissociative recombination of H/sup +//sub 3/ is not rapid, observational data can be used in conjunction with the theory to derive upper and lower bounds to the cosmic deuterium-hydrogen abundance ratio. We find that (D)/(H) is at least 3.4 x 10/sup -6/ and at most 4.0 x 10/sup -5/ with a probable value of 1 x 10/sup -5/. Because of the reaction HCO/sup +/+D..-->..DCO/sup +/+H, upper limits can be derived for the fractional ionization which depend only weakly on the cosmic ray flux, zeta. In four clouds, the upper limits to the fractional ionization lie between 1.1 x 10/sup -6/ and 1.5 x 10/sup -6/ if zeta = 10/sup -7/ s/sup -1/ and between 3.1 x 10/sup -6/ and 1.8 x 10/sup -6/ if zeta = 10/sup -16/ s/sup -1/.

  2. Deuterium fractionation in the Ophiuchus molecular cloud

    NASA Astrophysics Data System (ADS)

    Punanova, A.; Caselli, P.; Pon, A.; Belloche, A.; André, Ph.

    2016-03-01

    Context. In cold (T< 25 K) and dense (nH> 104 cm-3) interstellar clouds, molecules such as CO are significantly frozen onto dust grain surfaces. Deuterium fractionation is known to be very efficient in these conditions as CO limits the abundance of H3+, which is the starting point of deuterium chemistry. In particular, N2D+ is an excellent tracer of dense and cold gas in star-forming regions. Aims: We measure the deuterium fraction, RD, and the CO depletion factor, fd, towards a number of starless and protostellar cores in the L1688 region of the Ophiuchus molecular cloud complex and search for variations based upon environmental differences across L1688. The kinematic properties of the dense gas traced by the N2H+ and N2D+ (1-0) lines are also discussed. Methods: Deuterium fraction has been measured via observations of the J = 1-0 transition of N2H+ and N2D+ towards 33 dense cores in different regions of L1688. We estimated the CO depletion factor using C17O(1-0) and 850 μm dust continuum emission from the SCUBA survey. We carried out all line observations with the IRAM 30 m antenna. Results: The dense cores show large (≃2-40%) deuterium fractions with significant variations between the sub-regions of L1688. The CO depletion factor also varies from one region to another (between ≃1 and 7). Two different correlations are found between deuterium fraction and CO depletion factor: cores in regions A, B2, and I show increasing RD with increasing fd, similar to previous studies of deuterium fraction in pre-stellar cores; cores in regions B1, B1B2, C, E, F, and H show a steeper RD - fd correlation with large deuterium fractions occurring in fairly quiescent gas with relatively low CO freeze-out factors. These are probably recently formed, centrally concentrated starless cores, which have not yet started the contraction phase towards protostellar formation. We also find that the deuterium fraction is affected by the amount of turbulence, dust temperature, and

  3. Isotopic Anomalies in Primitive Solar System Matter: Spin-State-Dependent Fractionation of Nitrogen and Deuterium in Interstellar Clouds

    NASA Technical Reports Server (NTRS)

    Wirstrom, Eva S.; Charnley, Steven B.; Cordiner, Martin A.; Milam, Stefanie N.

    2012-01-01

    Organic material found in meteorites and interplanetary dust particles is enriched in D and N-15. This is consistent with the idea that the functional groups carrying these isotopic anomalies, nitriles and amines, were formed by ion-molecule chemistry in the protosolar nebula, Theoretical models of interstellar fractionation at low temperatures predict large enrichments in both D and N-15 and can account for the largest isotopic enrichments measured in carbonaceous meteorites. However, more recent measurements have shown that, in some primitive samples, a large N-15 enrichment does not correlate with one in D, and that some D-enriched primitive material displays little, if any, N-15 enrichment. By considering the spin-state dependence in ion-molecule reactions involving the ortho and para forms of H2, we show that ammonia and related molecules can exhibit such a wide range of fractionation for both N-15 and D in dense cloud cores. We also show that while the nitriles, HCN and HNC, contain the greatest N=15 enrichment, this is not expected to correlate with extreme D enrichment. These calculations therefore support the view that solar system N-15 and D isotopic anomalies have an interstellar heritage. We also compare our results to existing astronomical observations and briefly discuss future tests of this model.

  4. Isotopic Anomalies in Primitive Solar System Matter: Spin-State Dependent Fractionation of Nitrogen and Deuterium in Interstellar Clouds

    NASA Technical Reports Server (NTRS)

    Wirstrom, Eva S.; Charnley, Steven B.; Cordiner, Martin A.; Milan, Stefanie N.

    2012-01-01

    Organic material found in meteorites and interplanetary dust particles is enriched in D and N-15, This is consistent with the idea that the functional groups carrying these isotopic anomalies, nitriles and amines, were formed by ion-molecule chemistry in the protosolar core. Theoretical models of interstellar fractionation at low temperatures predict large enrichments in both D and N-15 and can account for the largest isotop c enrichments measured in carbonaceous meteorites, However, more recent measurements have shown that, in some primitive samples, a large N-15 enrichment does not correlate with one in D, and that some D-enriched primitive material displays little, if any, N-15 enrichment. By considering the spin-state dependence in ion-molecule reactions involving the ortho and para forms of H2, we show that ammonia and related molecules can exhibit such a wide range of fractionation for both N-15 and D in dense cloud cores, We also show that while the nitriles, HCN and HNC, contain the greatest N-15 enrichment, this is not expected to correlate with extreme D emichment. These calculations therefore support the view that Solar System N-15 and D isotopic anomalies have an interstellar heritage, We also compare our results to existing astronomical observations and briefly discuss future tests of this model.

  5. ISOTOPIC ANOMALIES IN PRIMITIVE SOLAR SYSTEM MATTER: SPIN-STATE-DEPENDENT FRACTIONATION OF NITROGEN AND DEUTERIUM IN INTERSTELLAR CLOUDS

    SciTech Connect

    Wirstroem, Eva S.; Cordiner, Martin A.; Charnley, Steven B.; Milam, Stefanie N.

    2012-09-20

    Organic material found in meteorites and interplanetary dust particles is enriched in D and {sup 15}N. This is consistent with the idea that the functional groups carrying these isotopic anomalies, nitriles and amines, were formed by ion-molecule chemistry in the protosolar nebula. Theoretical models of interstellar fractionation at low temperatures predict large enrichments in both D and {sup 15}N and can account for the largest isotopic enrichments measured in carbonaceous meteorites. However, more recent measurements have shown that, in some primitive samples, a large {sup 15}N enrichment does not correlate with one in D, and that some D-enriched primitive material displays little, if any, {sup 15}N enrichment. By considering the spin-state dependence in ion-molecule reactions involving the ortho and para forms of H{sub 2}, we show that ammonia and related molecules can exhibit such a wide range of fractionation for both {sup 15}N and D in dense cloud cores. We also show that while the nitriles, HCN and HNC, contain the greatest {sup 15}N enrichment, this is not expected to correlate with extreme D enrichment. These calculations therefore support the view that solar system {sup 15}N and D isotopic anomalies have an interstellar heritage. We also compare our results to existing astronomical observations and briefly discuss future tests of this model.

  6. Calculations of ion-molecule deuterium fractionation reactions involving HD

    NASA Technical Reports Server (NTRS)

    Maluendes, Sergio A.; Mclean, A. D.; Herbst, Eric

    1992-01-01

    Gas-phase chemical models of deuterium fractionation in dense interstellar clouds utilize a small number of exothermic reactions to achieve fractionation. Although HD is a major repository of deuterium, it appears not to exchange deuterium with many molecular ions. Useful semiquantitative reasons have been given for the unusual lack of reactivity of exothermic ion-HD deuterium exchange systems, but quantum chemical studies are needed to understand these ideas in more detail and to determine if the lack of reactivity pertains at very low temperatures not studied in the laboratory, or whether tunneling can drive the reactions. Accordingly, the potential energy surfaces of three representative ion-molecule exchange reactions involving protonated ions and HD have been investigated with ab initio quantum chemical techniques. Our results generally confirm the semiquantitative picture as to which reactions are likely to occur and show that tunneling at low temperatures is unlikely to alter this picture.

  7. Fluence dependence of deuterium retention in oxidized SS-316

    NASA Astrophysics Data System (ADS)

    Oya, Yasuhisa; Suzuki, Sachiko; Matsuyama, Masao; Hayashi, Takumi; Yamanishi, Toshihiko; Asakura, Yamato; Okuno, Kenji

    2011-10-01

    The ion fluence dependence of deuterium retention in SS-316 during oxidation at a temperature of 673 K was studied to evaluate the dynamics of deuterium retention in the oxide layer of SS-316. The correlation between the chemical state of stainless steel and deuterium retention was evaluated using XPS and TDS. It was found that the major deuterium desorption temperatures were located at around 660 K and 935 K, which correspond to the desorption of deuterium trapped as hydroxide. The deuterium retention increased with increasing deuterium ion fluence, since the deuterium retention as hydroxide increased significantly. However, retention saturated at an ion fluence of ˜2.5 × 10 21 D + m -2. The XPS result showed that FeOOD was formed on the surface, although pure Fe also remained in the oxide layer. These facts indicate the nature of the oxide layer have a key role in deuterium trapping behavior.

  8. The Gas-Phase Deuterium Fractionation of Formaldehyde

    NASA Astrophysics Data System (ADS)

    Osamura, Yoshihiro; Roberts, Helen; Herbst, Eric

    2005-03-01

    The dominant mechanism for the deuteration of formaldehyde in the gas phase of low-temperature interstellar cloud cores occurs via reaction with the deuterating ions H2D+, HD+2, and D+3. Until now, it has been assumed that deuteration leads to an ion that, on recombination with electrons, can produce a deuterated neutral species with a statistical branching fraction. Quantum chemical calculations reported here, however, show an entirely different picture, in which the deuteration of formaldehyde leads to the molecular ion H2COD+, where the deuterium binds only on the oxygen side of the molecule. The structure is quite stable, while an alternative structure, H2DCO+, cannot be produced in a straightforward manner. Dissociative recombination of H2COD+ to reproduce a formaldehyde structure then removes the deuteration if the dissociation is direct, i.e., it occurs without change of structure. There are several possible indirect mechanisms by which dissociative recombination can lead to HDCO, however. For example, if the direct products are HCOD+H, it is possible that subsequent isomerization to HDCO can occur, although this involved process is unlikely. Another possibility is isomerization during the actual dissociation of the H2COD intermediate. Models of deuterium fractionation in which dissociative recombination is predominantly direct are presented, and it is found that the deuterium fractionation of formaldehyde to form both HDCO and D2CO can still occur via other mechanisms, although with less efficiency than previously obtained. If the dissociative recombination is half indirect, however, then we can recover the previously calculated efficiency.

  9. CORRELATING INFALL WITH DEUTERIUM FRACTIONATION IN DENSE CORES

    SciTech Connect

    Schnee, Scott; Brunetti, Nathan; Friesen, Rachel; Di Francesco, James; Johnstone, Doug; Pon, Andy; Caselli, Paola

    2013-11-10

    We present a survey of HCO{sup +} (3-2) observations pointed toward dense cores with previous measurements of N(N{sub 2}D{sup +})/N(N{sub 2}H{sup +}). Of the 26 cores in this survey, 5 show the spectroscopic signature of outward motion, 9 exhibit neither inward nor outward motion, 11 appear to be infalling, and 1 is not detected. We compare the degree of deuterium fractionation with infall velocities calculated from the HCO{sup +} spectra and find that those cores with [D]/[H] > 0.1 are more likely to have the signature of inward motions than cores with smaller [D]/[H] ratios. Infall motions are also much more common in cores with masses exceeding their thermal Jeans masses. The fastest infall velocity measured belongs to one of the two protostellar cores in our survey, L1521F, and the observed motions are typically on the order of the sound speed.

  10. AN ANALYSIS OF THE DEUTERIUM FRACTIONATION OF STAR-FORMING CORES IN THE PERSEUS MOLECULAR CLOUD

    SciTech Connect

    Friesen, R. K.; Kirk, H. M.; Shirley, Y. L.

    2013-03-01

    We have performed a pointed survey of N{sub 2}D{sup +} 2-1 and N{sub 2}D{sup +} 3-2 emission toward 64 N{sub 2}H{sup +}-bright starless and protostellar cores in the Perseus molecular cloud using the Arizona Radio Observatory Submillimeter Telescope and Kitt Peak 12 m telescope. We find a mean deuterium fractionation in N{sub 2}H{sup +}, R{sub D} = N(N{sub 2}D{sup +})/N(N{sub 2}H{sup +}), of 0.08, with a maximum R{sub D} = 0.2. In detected sources, we find no significant difference in the deuterium fractionation between starless and protostellar cores, nor between cores in clustered or isolated environments. We compare the deuterium fraction in N{sub 2}H{sup +} with parameters linked to advanced core evolution. We only find significant correlations between the deuterium fraction and increased H{sub 2} column density, as well as with increased central core density, for all cores. Toward protostellar sources, we additionally find a significant anticorrelation between R{sub D} and bolometric temperature. We show that the Perseus cores are characterized by low CO depletion values relative to previous studies of star-forming cores, similar to recent results in the Ophiuchus molecular cloud. We suggest that the low average CO depletion is the dominant mechanism that constrains the average deuterium fractionation in the Perseus cores to small values. While current equilibrium and dynamic chemical models are able to reproduce the range of deuterium fractionation values we find in Perseus, reproducing the scatter across the cores requires variation in parameters such as the ionization fraction or the ortho-to-para-H{sub 2} ratio across the cloud, or a range in core evolution timescales.

  11. An Analysis of the Deuterium Fractionation of Star-forming Cores in the Perseus Molecular Cloud

    NASA Astrophysics Data System (ADS)

    Friesen, R. K.; Kirk, H. M.; Shirley, Y. L.

    2013-03-01

    We have performed a pointed survey of N2D+ 2-1 and N2D+ 3-2 emission toward 64 N2H+-bright starless and protostellar cores in the Perseus molecular cloud using the Arizona Radio Observatory Submillimeter Telescope and Kitt Peak 12 m telescope. We find a mean deuterium fractionation in N2H+, RD = N(N2D+)/N(N2H+), of 0.08, with a maximum RD = 0.2. In detected sources, we find no significant difference in the deuterium fractionation between starless and protostellar cores, nor between cores in clustered or isolated environments. We compare the deuterium fraction in N2H+ with parameters linked to advanced core evolution. We only find significant correlations between the deuterium fraction and increased H2 column density, as well as with increased central core density, for all cores. Toward protostellar sources, we additionally find a significant anticorrelation between RD and bolometric temperature. We show that the Perseus cores are characterized by low CO depletion values relative to previous studies of star-forming cores, similar to recent results in the Ophiuchus molecular cloud. We suggest that the low average CO depletion is the dominant mechanism that constrains the average deuterium fractionation in the Perseus cores to small values. While current equilibrium and dynamic chemical models are able to reproduce the range of deuterium fractionation values we find in Perseus, reproducing the scatter across the cores requires variation in parameters such as the ionization fraction or the ortho-to-para-H2 ratio across the cloud, or a range in core evolution timescales.

  12. Deuterium fractionation of water in the Solar nebula

    NASA Astrophysics Data System (ADS)

    Albertsson, Tobias; Semenov, Dmitry; Henning, Thomas

    2013-07-01

    Water evaporates in the inner regions of protoplanetary disks and is frozen onto grains in the outer regions. Therefore its presence in vast quantities on Earth is puzzling. Subsequent delivery through bombardment by primitive bodies formed in the outer icy regions is the favored mechanism. By studying water D/H ratios one hopes to understand whether the water was mainly delivered by comets or asteroids. Using an extended deuterium chemistry network coupled to a 2D chemo-dynamical disk model, we investigate the evolution of the D/H ratio of water in the young Solar nebula. We find that both the laminar and mixing Solar nebula models show the Earth's ocean water D/H ratio at 2-3 AU. In addition, the 2D-mixing model explains better the water D/H values observed in the Oort- and Jupiter-family comets.

  13. Deuterium Fractionation on Mars and Evolutionary Implications for Water

    NASA Astrophysics Data System (ADS)

    Pathare, A. V.; Paige, D. A.

    1998-09-01

    Deuterium/Hydrogen (D/H) in the Martian atmosphere is enriched relative to terrestrial Standard Mean Ocean Water (SMOW) by a factor of 5.5. Yung et al. (1) photochemically modeled the escape efficiency (R) of D relative to H and obtained 0.32. Such high R implies that Mars experienced massive water loss early in its history, and cannot have significantly exchanged with juvenile water since. But Yung et al. (1) did not consider solar cycle related variations in both exospheric temperature and ionospheric chemistry, and when we accounted for changes in solar activity we obtained R = 0.17, which as we discussed last year is consistent with episodic juvenile water resupply. However, earlier this year Krasnopolsky et al. (2) obtained an even lower R = 0.02, based on spectroscopic measurements of deuterium which they could only reproduce by assuming that the ratio of (HD/H2) / (HDO/H2O) at the 80 km base of the exosphere was less than 10 based on Yung et al. (1). To explain this significant deviation, Krasnopolsky et al. (2) argued that partitioning of D into HD and HDO is controlled not kinetically but rather thermodynamically. However, as pointed out by Yung and Kass (3), this explanation would require an isotopic exchange rate coefficient over 10 orders of magnitude larger than that measured for this thermodynamic reaction in the laboratory. Therefore, we explore within the confines of the more likely applicable kinetic photochemical theory whether less extreme variations in exospheric and/or lower atmospheric reaction rate constants could result in a resolution to this dilemma. For example, variations in the vertical distribution of D could allow higher densities of HD at 80 km to be consistent with the new spectroscopic observations, or changes in the tropospheric conversion of HDO into HD could lessen the predicted amount of HD at 80 km. In addition, we examine the new climatological implications of R < 0.32 upon the evolution of Martian water, as massive

  14. Deuterium Fractionation in Analogs of Interstellar Ices: Laboratory Measurements

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    A question of key interest in the field of Astrobiology is the extent to which organic compounds made in space may play a role in the origin of life in planetary systems. In general, the best proof that at least some interstellar materials survive incorporation into forming stellar/planetary systems is their identification in extraterrestrial samples through detection of the isotopic anomalies they may carry. In the case of organic compounds, the chief isotopic anomalies that might be expected are the enrichment of D and 15N. and such enrichments are seen in primitive extraterrestrial materials, for example, in the organics in carbonaceous chondrites and interplanetary dust particles. In my talk I will review the various astrochemical processes by which deuterium can become enriched in organic compounds and will discuss some recent laboratory experiments that examine one of these processes in particular. name]y the UV photolysis of interstellar ices. Finally, I will review the current state of our knowledge of D enrichments in primitive solar system materials and discuss the constraints these data place on the relative importance of the various possible interstellar D enrichment processes.

  15. Fractionation of hydrogen and deuterium on Venus due to collisional ejection

    NASA Technical Reports Server (NTRS)

    Gurwell, Mark A.; Yung, Yuk L.

    1993-01-01

    The collisional ejection process for hydrogen on Venus is reanalyzed. Improved values for the efficiency of H and D escape as a function of the ionospheric temperature are reported. It is proposed that the reduction of the hydrogen flux for collisional ejection be reduced from 8 to 3.5 x 10 exp 6/sq cm/s, and a revised D/H fractional factor of 0.47 due to collisional ejection is suggested. The resulting deuterium flux is 3.1 x 10 exp 4/sq cm/s, roughly six times the flux due to charge exchange, making collisional ejection the dominant escape mechanism for deuterium on Venus.

  16. Fractionation of hydrogen and deuterium on Venus due to collisional ejection

    NASA Astrophysics Data System (ADS)

    Gurwell, M. A.; Yung, Y. L.

    1993-02-01

    The collisional ejection process for hydrogen on Venus is reanalyzed. Improved values for the efficiency of H and D escape as a function of the ionospheric temperature are reported. It is proposed that the reduction of the hydrogen flux for collisional ejection be reduced from 8 to 3.5 x 10 exp 6/sq cm/s, and a revised D/H fractional factor of 0.47 due to collisional ejection is suggested. The resulting deuterium flux is 3.1 x 10 exp 4/sq cm/s, roughly six times the flux due to charge exchange, making collisional ejection the dominant escape mechanism for deuterium on Venus.

  17. Deuterium Fractionation and Ionization Degree in Massive Protostellar/cluster Cores

    NASA Astrophysics Data System (ADS)

    Chen, Huei-Ru; Liu, Sheng-Yuan; Su, Yu-Nung

    2013-03-01

    We have conducted a survey of deuterium fractionation of N2H+, RD (N2H+) ≡ N(N2D+)/N(N2H+), with the Arizona Radio Observatory (ARO) Submillimeter Telescope (SMT) to assess the use of RD (N2H+) as an evolutionary tracer among massive protostellar/cluster cores in early stages. Our sample includes 32 dense cores in various evolutionary stages, from high-mass starless cores (HMSCs), high-mass protostellar objects (HMPOs), to ultra-compact (UC) HII regions, in infrared dark clouds (IRDCs) and high infrared extinction clouds. The results show a decreasing trend in deuterium fractionation with evolutionary stage traced by gas temperature and line width (Fig. 1). A moderate increasing trend of deuterium fractionation with the CO depletion factor is also found among cores in IRDCs and HMSCs. These suggest a general chemical behavior of deuterated species in low- and high-mass protostellar candidates. Upper limits to the ionization degree are also estimated to be in the range of 4 × 10-8 - 5 × 10-6.

  18. Temperature dependence of deuterium retention in tungsten deposits by deuterium ion irradiation

    NASA Astrophysics Data System (ADS)

    Katayama, K.; Uehara, K.; Date, H.; Fukada, S.; Watanabe, H.

    2015-08-01

    Tungsten (W) deposits were formed by hydrogen plasma sputtering and blisters were observed on the surface. The W deposits and W foils were exposed to deuterium ions with 2 keV-D2+ to doses of 1.0 × 1021 D2+/m2 at 294 and 773 K in addition to 573 K in the present authors' previous work. Hydrogen isotopes release behaviors from the W deposits and W foils were observed by the thermal desorption spectroscopy method. The amount of deuterium released from the W deposit was considerably larger than that from W foil. The obtained deuterium retention in D/m2 was in the range of deuterium retention in polycrystalline tungsten. Not only implanted deuterium but also hydrogen, which was incorporated during the sputtering-deposition process, were released from the W deposits. A hydrogen release peak at around 1100 K was observed for the W deposits. This is considered to be due to the rupture of the blisters.

  19. New Extended Deuterium Fractionation Model: Assessment at Dense ISM Conditions and Sensitivity Analysis

    NASA Astrophysics Data System (ADS)

    Albertsson, T.; Semenov, D. A.; Vasyunin, A. I.; Henning, Th.; Herbst, E.

    2013-08-01

    Observations of deuterated species are useful in probing the temperature, ionization level, evolutionary stage, chemistry, and thermal history of astrophysical environments. The analysis of data from the Atacama Large Millimeter Array and other new telescopes requires an elaborate model of deuterium fractionation. This paper presents a publicly available chemical network with multi-deuterated species and an extended, up-to-date set of gas-phase and surface reactions. To test this network, we simulate deuterium fractionation in diverse interstellar sources. Two cases of initial abundances are considered: (1) atomic except for H2 and HD, and (2) molecular from a prestellar core. We reproduce the observed D/H ratios of many deuterated molecules, and sort the species according to their sensitivity to temperature gradients and initial abundances. We find that many multiply deuterated species produced at 10 K retain enhanced D/H ratios at temperatures <~ 100 K. We study how recent updates to reaction rates affect calculated D/H ratios, and perform a detailed sensitivity analysis of the uncertainties of the gas-phase reaction rates in the network. We find that uncertainties are generally lower in dark cloud environments than in warm infrared dark clouds and that uncertainties increase with the size of the molecule and number of D-atoms. A set of the most problematic reactions is presented. We list potentially observable deuterated species predicted to be abundant in low- and high-mass star-formation regions.

  20. NEW EXTENDED DEUTERIUM FRACTIONATION MODEL: ASSESSMENT AT DENSE ISM CONDITIONS AND SENSITIVITY ANALYSIS

    SciTech Connect

    Albertsson, T.; Semenov, D. A.; Henning, Th.; Vasyunin, A. I.; Herbst, E.

    2013-08-15

    Observations of deuterated species are useful in probing the temperature, ionization level, evolutionary stage, chemistry, and thermal history of astrophysical environments. The analysis of data from the Atacama Large Millimeter Array and other new telescopes requires an elaborate model of deuterium fractionation. This paper presents a publicly available chemical network with multi-deuterated species and an extended, up-to-date set of gas-phase and surface reactions. To test this network, we simulate deuterium fractionation in diverse interstellar sources. Two cases of initial abundances are considered: (1) atomic except for H{sub 2} and HD, and (2) molecular from a prestellar core. We reproduce the observed D/H ratios of many deuterated molecules, and sort the species according to their sensitivity to temperature gradients and initial abundances. We find that many multiply deuterated species produced at 10 K retain enhanced D/H ratios at temperatures {approx}< 100 K. We study how recent updates to reaction rates affect calculated D/H ratios, and perform a detailed sensitivity analysis of the uncertainties of the gas-phase reaction rates in the network. We find that uncertainties are generally lower in dark cloud environments than in warm infrared dark clouds and that uncertainties increase with the size of the molecule and number of D-atoms. A set of the most problematic reactions is presented. We list potentially observable deuterated species predicted to be abundant in low- and high-mass star-formation regions.

  1. Hydrated fractions of cellulosics probed by infrared spectroscopy coupled with dynamics of deuterium exchange.

    PubMed

    Driemeier, Carlos; Mendes, Fernanda M; Ling, Liu Yi

    2015-08-20

    This article presents a novel method to selectively probe the non-crystalline, hydrated fractions of cellulosic biomass. The method is based on time-resolved infrared spectra analyzed to provide information on spectral and dynamical features of deuterium exchange (OH → OD) in D2O atmosphere. We assign deuterium exchange spectral regions (700-3800 cm(-1)) and explore changes due to relative humidity, different cellulosic samples, and infrared polarization. Here, two results are highlighted. First, a wide range of celluloses isolated from plants show remarkable spectral similarities whatever the relative amounts of cellulose and xylan. This result supports an inherent type of hydrated disorder which is mostly insensitive to the molecular identities of the associated polysaccharides. Second, polarized infrared analysis of cotton reveals hydrated cellulose having chains preferentially aligned with those of crystals, while the hydroxyls of hydrated cellulose present much more randomized orientation. Our results provide new insights on molecular and group orientation and on hydrogen bonding in hydrated fractions of cellulosic biomass. PMID:25965468

  2. Deuterium Fractionation: The Ariadne's Thread from the Precollapse Phase to Meteorites and Comets Today

    NASA Astrophysics Data System (ADS)

    Ceccarelli, C.; Caselli, P.; Bockelée-Morvan, D.; Mousis, O.; Pizzarello, S.; Robert, F.; Semenov, D.

    The solar system formed about 4.6 billion years (b.y.) ago from condensation of matter inside a molecular cloud. Trying to reconstruct what happened is the goal of this chapter. For that, we combine our understanding of Galactic objects that will eventually form new suns and planetary systems with our knowledge on comets, meteorites, and small bodies of the solar system today. The specific tool we are using is molecular deuteration, namely the amount of deuterium with respect to hydrogen in molecules. This is the Ariadne’s thread that helps us to find the way out from a labyrinth of possible histories of our solar system. The chapter reviews the observations and theories of the deuterium fractionation in prestellar cores, protostars, protoplanetary disks (PPDs), comets, interplanetary dust particles (IDPs), and meteorites and links them together to build up a coherent picture of the history of the solar system formation. We emphasize the interdisciplinary nature of this chapter, which gathers together researchers from different communities with the common goal of understanding solar system history.

  3. Variability of Deuterium Fractionation Associated With Soil Uptake of Atmospheric Molecular Hydrogen

    NASA Astrophysics Data System (ADS)

    Rahn, T.; Randerson, J. T.; Eiler, J.

    2005-12-01

    Molecular hydrogen (H2) is the second most abundant reduced gas in the atmosphere (after methane) with a globally averaged mixing ratio of ~530 nmol/mol. Its largest sources are photochemical oxidation of methane and non-methane hydrocarbons with other recognized sources that include biomass burning, fossil fuel burning, nitrogen fixation, and ocean degassing. These sources are balanced by reaction of H2 with hydroxyl radicals (~25%) in the atmosphere and by deposition at the terrestrial soil surface (~75%). As with other atmospheric trace gases, the stable isotopic content of H2 has the potential to help quantify the various aspects of its production and destruction. The average deuterium content of H2 is dDH2 = ~130 ‰ relative to Standard Mean Ocean Water. While recent studies have begun to elucidate the deuterium content of the individual sources of H2 and the fractionation associated with hydroxyl oxidation has been well established in the laboratory, there are still few data documenting the fractionation associated with soil uptake. We measured the fractionation associated with soil uptake in May, June and August of 2002 in three upland ecosystems that were part of an Alaskan fire chronosequence. Fire occurred at these sites in 1999, 1987, and ~1920. Grasses and herbaceous vegetation establish initially after fire and are gradually replaced by deciduous trees and finally by evergreen trees and moss. All three sites were in interior Alaska near the town of Delta Junction (63° 54'N, 145° 40'W). Fluxes were measured with a Plexiglas flux chamber (8 liter volume) with a manifold of four ~400 ml double-valved glass flasks in parallel and a diaphragm pump for circulation (5 SLPM). Flasks were continuously flushed by the circulating system and isolated sequentially; they were then returned to the laboratory at Caltech for subsequent analysis. In the field, the chamber was seated on Plexiglas collars that were installed prior to initiating the study and left in

  4. DEUTERIUM FRACTIONATION AS AN EVOLUTIONARY PROBE IN MASSIVE PROTOSTELLAR/CLUSTER CORES

    SciTech Connect

    Chen, Huei-Ru; Wang, Mei-Yan; Liu, Sheng-Yuan; Su, Yu-Nung

    2011-12-20

    Clouds of high infrared extinction are promising sites of massive star/cluster formation. A large number of cloud cores discovered in recent years allow for the investigation of a possible evolutionary sequence among cores in early phases. We have conducted a survey of deuterium fractionation toward 15 dense cores in various evolutionary stages, from high-mass starless cores to ultracompact H II regions, in the massive star-forming clouds of high extinction, G34.43+0.24, IRAS 18151-1208, and IRAS 18223-1243, with the Submillimeter Telescope. Spectra of N{sub 2}H{sup +} (3-2), N{sub 2}D{sup +} (3-2), and C{sup 18}O (2-1) were observed to derive the deuterium fractionation of N{sub 2}H{sup +}, D{sub frac} {identical_to} N(N{sub 2}D{sup +})/N(N{sub 2}H{sup +}), as well as the CO depletion factor for every selected core. Our results show a decreasing trend in D{sub frac} with both gas temperature and line width. Since colder and quiescent gas is likely to be associated with less evolved cores, larger D{sub frac} appears to correlate with early phases of core evolution. Such decreasing trend resembles the behavior of D{sub frac} in the low-mass protostellar cores and is consistent with several earlier studies in high-mass protostellar cores. We also find a moderate increasing trend of D{sub frac} with the CO depletion factor, suggesting that sublimation of ice mantles alters the competition in the chemical reactions and reduces D{sub frac}. Our findings suggest a general chemical behavior of deuterated species in both low- and high-mass protostellar candidates at early stages. In addition, upper limits to the ionization degree are estimated to be within 2 Multiplication-Sign 10{sup -7} and 5 Multiplication-Sign 10{sup -6}. The four quiescent cores have marginal field-neutral coupling and perhaps favor turbulent cooling flows.

  5. Deuterium Fractionation during Amino Acid Formation by Photolysis of Interstellar Ice Analogs Containing Deuterated Methanol

    NASA Astrophysics Data System (ADS)

    Oba, Yasuhiro; Takano, Yoshinori; Watanabe, Naoki; Kouchi, Akira

    2016-08-01

    Deuterium (D) atoms in interstellar deuterated methanol might be distributed into complex organic molecules through molecular evolution by photochemical reactions in interstellar grains. In this study, we use a state-of-the-art high-resolution mass spectrometer coupled with a high-performance liquid chromatography system to quantitatively analyze amino acids and their deuterated isotopologues formed by the photolysis of interstellar ice analogs containing singly deuterated methanol CH2DOH at 10 K. Five amino acids (glycine, α-alanine, β-alanine, sarcosine, and serine) and their deuterated isotopologues whose D atoms are bound to carbon atoms are detected in organic residues formed by photolysis followed by warming up to room temperature. The abundances of singly deuterated amino acids are in the range of 0.3–1.1 relative to each nondeuterated counterpart, and the relative abundances of doubly and triply deuterated species decrease with an increasing number of D atoms in a molecule. The abundances of amino acids increase by a factor of more than five upon the hydrolysis of the organic residues, leading to decreases in the relative abundances of deuterated species for α-alanine and β-alanine. On the other hand, the relative abundances of the deuterated isotopologues of the other three amino acids did not decrease upon hydrolysis, indicating different formation mechanisms of these two groups upon hydrolysis. The present study facilitates both qualitative and quantitative evaluations of D fractionation during molecular evolution in the interstellar medium.

  6. Water deuterium fractionation in the low-mass protostar NGC1333-IRAS2A

    NASA Astrophysics Data System (ADS)

    Liu, F.-C.; Parise, B.; Kristensen, L.; Visser, R.; van Dishoeck, E. F.; Güsten, R.

    2011-03-01

    Context. Although deuterium enrichment of water may provide an essential piece of information in the understanding of the formation of comets and protoplanetary systems, only a few studies up to now have aimed at deriving the HDO/H2O ratio in low-mass star forming regions. Previous studies of the molecular deuteration toward the solar-type class 0 protostar, IRAS 16293-2422, have shown that the D/H ratio of water is significantly lower than other grain-surface-formed molecules. It is not clear if this property is general or particular to this source. Aims: In order to see if the results toward IRAS 16293-2422 are particular, we aimed at studying water deuterium fractionation in a second low-mass solar-type protostar, NGC1333-IRAS2A. Methods: Using the 1-D radiative transfer code RATRAN, we analyzed five HDO transitions observed with the IRAM 30 m, JCMT, and APEX telescopes. We assumed that the abundance profile of HDO in the envelope is a step function, with two different values in the inner warm (T > 100 K) and outer cold (T < 100 K) regions of the protostellar envelope. Results: The inner and outer abundance of HDO is found to be well constrained at the 3σ level. The obtained HDO inner and outer fractional abundances are xHDO_in = 6.6 × 10-8-1.0 × 10-7(3σ) and x^{HDO}out=9×10-11= 9 × 10-11-1.0-1.8 × 10-9(3σ). These values are close to those in IRAS 16293-2422, which suggests that HDO may be formed by the same mechanisms in these two solar-type protostars. Taking into account the (rather poorly onstrained) H2O abundance profile deduced from Herschel observations, the derived HDO/H2O in the inner envelope is ≥1% and in the outer envelope it is 0.9%-18%. These values are more than one order of magnitude higher than what is measured in comets. If the same ratios apply to the protosolar nebula, this would imply that there is some efficient reprocessing of the material between the protostellar and cometary phases. Conclusions: The H2O inner fractional

  7. Dynamics, CO depletion, and deuterium fractionation of the dense condensations within the fragmented prestellar core Orion B9-SMM 6

    NASA Astrophysics Data System (ADS)

    Miettinen, O.; Offner, S. S. R.

    2013-07-01

    Context. Low-mass prestellar cores are rarely found to be fragmented into smaller condensations, but studying any substructure, where present, is essential for understanding the origin of multiple stellar systems. Aims: We attempt to better understand the kinematics and dynamics of the subfragments inside the prestellar core SMM 6 in Orion B9. Another goal of the present study is to constrain the evolutionary stage of the condensations by investigating the levels of CO depletion and deuterium fractionation. Methods: We used the APEX telescope to observe the molecular lines C17O(2-1), N2H+(3-2), and N2D+(3-2) towards the condensations. We used the line data in conjunction with our previous SABOCA 350-μm dust continuum map of the source. Results: The condensations are characterised by subsonic internal non-thermal motions (σNT ≃ 0.5cs), and most of them appear to be gravitationally bound. The dispersion of the N2H+ velocity centroids among the condensations is very low (0.02 km s-1). The CO depletion factors we derive, fD = 0.8 ± 0.4-3.6 ± 1.5, do not suggest any significant CO freeze-out, but this may be due to the canonical CO abundance we adopt. The fractional abundances of N2H+ and N2D+ with respect to H2 are found to be ~0.9-2.3 × 10-9 and ~4.9-9.9 × 10-10, respectively. The deuterium fractionation of N2H+ lies in the range 0.30 ± 0.07-0.43 ± 0.09. Conclusions: The detected substructure inside SMM 6 is most likely the result of cylindrical Jeans-type gravitational fragmentation. We estimate the timescale for this fragmentation to be ~1.8 × 105 yr. The condensations are unlikely to be able to interact with one another and coalesce before local gravitational collapse ensues. Moreover, significant mass growth of the condensations via competitive-like accretion from the parent core seems unfeasible. The high level of molecular deuteration in the condensations suggests that gas-phase CO should be strongly depleted. It also points towards an advanced stage

  8. Isotopic fractionation through water vapor condensation: The Deuteropause, a cold trap for deuterium in the atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Bertaux, Jean-Loup; Montmessin, Franck

    2001-12-01

    Recent observations of deuterium atoms at Lyman alpha with the Hubble Space Telescope have shown the puzzling result of a D/H ratio in the upper atmosphere of Mars to be 11 times samller than the D/H ratio in HDO and H2O of the lower atmosphere [Krasnopolsky et al., 1998]. One factor to explain this vertical variation was proposed: the photo-induced fractionation effect (PHIFE), due to a lower absorption cross section of solar UV of HDO compared to H2O [Cheng et al., 1999]. Here we suggest that in addition to PHIFE, this vertical variation of D/H ratio is also the result of preferred condensation of HDO in rising air, a process already documented in the Earth's upper stratosphere. Results of a cloud model, including condensation, sedimentation, and sublimation of icy particles in the atmosphere of Mars, are presented, supporting the efficiency of the condensation/evaporation fractionation effect (CEFE) as an important factor controlling the D/H ratio in the upper atmosphere of Mars. For a typical H2O profile, PHIFE provides a depletion factor of 2.5, while CEFE induces a factor of 3.5. The combined effects of PHIFE and CEFE (depletion factor of 9.5) can explain the paucity of D atoms in the upper atmosphere of Mars, implying a very low escape rate of deuterium at present and in the past and, correspondingly, a smaller quantity of H2O in the past.

  9. THE INITIAL CONDITIONS OF CLUSTERED STAR FORMATION. III. THE DEUTERIUM FRACTIONATION OF THE OPHIUCHUS B2 CORE

    SciTech Connect

    Friesen, R. K.; Di Francesco, J.; Myers, P. C.; Bourke, T. L.; Belloche, A.; Shirley, Y. L.; Andre, P.

    2010-08-01

    We present N{sub 2}D{sup +} 3-2 (IRAM), and H{sub 2}D{sup +} 1{sub 11}-1{sub 10} and N{sub 2}H{sup +} 4-3 (JCMT) maps of the small cluster-forming Ophiuchus B2 core in the nearby Ophiuchus molecular cloud. In conjunction with previously published N{sub 2}H{sup +} 1-0 observations, the N{sub 2}D{sup +} data reveal the deuterium fractionation in the high-density gas across Oph B2. The average deuterium fractionation R{sub D} = N(N{sub 2}D{sup +})/N(N{sub 2}H{sup +}) {approx} 0.03 over Oph B2, with several small scale R{sub D} peaks and a maximum R{sub D} = 0.1. The mean R{sub D} is consistent with previous results in isolated starless and protostellar cores. The column density distributions of both H{sub 2}D{sup +} and N{sub 2}D{sup +} show no correlation with total H{sub 2} column density. We find, however, an anticorrelation in deuterium fractionation with proximity to the embedded protostars in Oph B2 to distances {approx}>0.04 pc. Destruction mechanisms for deuterated molecules require gas temperatures greater than those previously determined through NH{sub 3} observations of Oph B2 to proceed. We present temperatures calculated for the dense core gas through the equating of non-thermal line widths for molecules (i.e., N{sub 2}D{sup +} and H{sub 2}D{sup +}) expected to trace the same core regions, but the observed complex line structures in B2 preclude finding a reasonable result in many locations. This method may, however, work well in isolated cores with less complicated velocity structures. Finally, we use R{sub D} and the H{sub 2}D{sup +} column density across Oph B2 to set a lower limit on the ionization fraction across the core, finding a mean x{sub e,lim} {approx}> few x 10{sup -8}. Our results show that care must be taken when using deuterated species as a probe of the physical conditions of dense gas in star-forming regions.

  10. Vapor Pressure Isotope Fractionation Effects in Planetary Atmospheres: Application to Deuterium

    NASA Astrophysics Data System (ADS)

    Fouchet, Thierry; Lellouch, Emmanuel

    2000-03-01

    The impact of the vapor pressure difference between deuterated and nondeuterated condensing molecules in planetary atmospheres is quantitatively assessed. This difference results in a loss of deuterium in the vapor phase above the condensation level. In Titan, Uranus, and Neptune, the effect on CH 3D is too subtle to alter current D/H ratio determinations. In Mars, the effect can induce a large depletion of HDO, starting about one scale height above the condensation level. Although the current infrared measurements of the D/H ratio appear to be almost unaffected, the intensity of disk-averaged millimetric HDO lines can be modified by about 10%. The effect is much stronger in limb sounding and can be easily detected from orbiter observations.

  11. Deuterium fractionation in the presolar nebula - Kinetic limitations on surface catalysis

    NASA Technical Reports Server (NTRS)

    Grinspoon, David H.; Lewis, John S.

    1987-01-01

    A quantitative test is presented for the possibility that grain-based catalysis could shorten the equilibration times of low temperature equilibrium fractionation sufficiently to account for the D/H ratio values of the solar system even at nebular temperatures. It is found that under the highly idealized conditions in which the full cosmic abundance of Ni is available for catalysis in pure, 5-micron grains, the equilibration time constant becomes greater than the nebular lifetime at temperatures below 560 K. This lower limit is not, however, sufficiently low to permit strong fractionation.

  12. Warm water deuterium fractionation in IRAS 16293-2422. The high-resolution ALMA and SMA view

    NASA Astrophysics Data System (ADS)

    Persson, M. V.; Jørgensen, J. K.; van Dishoeck, E. F.

    2013-01-01

    Context. Measuring the water deuterium fractionation in the inner warm regions of low-mass protostars has so far been hampered by poor angular resolution obtainable with single-dish ground- and space-based telescopes. Observations of water isotopologues using (sub)millimeter wavelength interferometers have the potential to shed light on this matter. Aims: To measure the water deuterium fractionation in the warm gas of the deeply-embedded protostellar binary IRAS 16293-2422. Methods: Observations toward IRAS 16293-2422 of the 53,2 - 44,1 transition of H218O at 692.07914 GHz from Atacama Large Millimeter/submillimeter Array (ALMA) as well as the 31,3 - 22,0 of H218O at 203.40752 GHz and the 31,2 - 22,1 transition of HDO at 225.89672 GHz from the Submillimeter Array (SMA) are presented. Results: The 692 GHz H218O line is seen toward both components of the binary protostar. Toward one of the components, "source B", the line is seen in absorption toward the continuum, slightly red-shifted from the systemic velocity, whereas emission is seen off-source at the systemic velocity. Toward the other component, "source A", the two HDO and H218O lines are detected as well with the SMA. From the H218O transitions the excitation temperature is estimated at 124 ± 12 K. The calculated HDO/H2O ratio is (9.2 ± 2.6) × 10-4 - significantly lower than previous estimates in the warm gas close to the source. It is also lower by a factor of ~5 than the ratio deduced in the outer envelope. Conclusions: Our observations reveal the physical and chemical structure of water vapor close to the protostars on solar-system scales. The red-shifted absorption detected toward source B is indicative of infall. The excitation temperature is consistent with the picture of water ice evaporation close to the protostar. The low HDO/H2O ratio deduced here suggests that the differences between the inner regions of the protostars and the Earth's oceans and comets are smaller than previously thought

  13. Deuterium excess in the Rayleigh model

    NASA Astrophysics Data System (ADS)

    Dütsch, Marina; Pfahl, Stephan; Sodemann, Harald

    2016-04-01

    The deuterium excess is a useful quantity for measuring nonequilibrium effects of isotopic fractionation, and can therefore provide information about the meteorological conditions in evaporation regions (e.g., relative humidity over the ocean or the fraction of plant transpiration over land). In addition to nonequilibrium fractionation, there are two other effects that can change the deuterium excess during phase transitions. The first is the dependence of the equilibrium fractionation factors on temperature, the second is the nonlinearity of the delta scale, on which the deuterium excess is defined. We tested the impact of these three effects (nonequilibrium, temperature and delta scale) in a simple Rayleigh condensation model simulating the isotopic composition of an air parcel during a moist adiabatic ascent. The delta scale effect is important especially for depleted air parcels where it can change the sign of the deuterium excess in the remaining vapour from negative to positive. In this case the deuterium excess to a large extent reflects an artefact of its own definition, which overwrites both the nonequilibrium and the temperature effect. This problem can be solved by an alternative definition for the deuterium excess that is not based on the delta scale.

  14. WATER DEUTERIUM FRACTIONATION IN THE INNER REGIONS OF TWO SOLAR-TYPE PROTOSTARS

    SciTech Connect

    Taquet, V.; Lopez-Sepulcre, A.; Ceccarelli, C.; Kahane, C.; Coutens, A.; Vastel, C.

    2013-05-10

    The [HDO]/[H{sub 2}O] ratio is a crucial parameter for probing the history of water formation. So far, it has been measured for only three solar-type protostars and yielded different results, possibly pointing to a substantially different history in their formation. In the present work, we report new interferometric observations of the HDO 4{sub 2,2}-4{sub 2,3} line for two solar-type protostars, IRAS2A and IRAS4A, located in the NGC 1333 region. In both sources, the detected HDO emission originates from a central compact unresolved region. A comparison with previously published interferometric observations of the H{sub 2}{sup 18}O 3{sub 1,3}-2{sub 2,0} line shows that the HDO and H{sub 2}O lines mostly come from the same region. A non-LTE large velocity gradient analysis of the HDO and H{sub 2}{sup 18}O line emissions, combined with published observations, provides an [HDO]/[H{sub 2}O] ratio of 0.3%-8% in IRAS2A and 0.5%-3% in IRAS4A. First, the water fractionation is lower than that of other molecules such as formaldehyde and methanol in the same sources. Second, it is similar to that measured in the solar-type protostar prototype, IRAS16293-2422, and, surprisingly enough, larger than that measured in NGC 1333 IRAS4B. The comparison of the measured values toward IRAS2A and IRAS4A with the predictions of our gas-grain model GRAINOBLE gives similar conclusions to those for IRAS 16293, arguing that these protostars share a similar chemical history, although they are located in different clouds.

  15. First-principles study of temperature-dependent diffusion coefficients: Hydrogen, deuterium, and tritium in α-Ti

    NASA Astrophysics Data System (ADS)

    Lu, Yong; Zhang, Ping

    2013-05-01

    We report the prediction of temperature-dependent diffusion coefficients of interstitial hydrogen, deuterium, and tritium atoms in α-Ti using transition state theory. The microscopic parameters in the pre-factor and activation energy of the impurity diffusion coefficients are obtained from first-principles total energy and phonon calculations including the full coupling between the vibrational modes of the diffusing atom with the host lattice. The dual occupancy case of impurity atom in the hcp matrix is considered, and four diffusion paths are combined to obtain the final diffusion coefficients. The calculated diffusion parameters show good agreement with experiments. Our numerical results indicate that the diffusions of deuterium and tritium atoms are slower than that of the hydrogen atom at temperatures above 425 K and 390 K, respectively.

  16. The Mass-Dependence of Cadmium Isotope Fractionation During Evaporation

    NASA Astrophysics Data System (ADS)

    Rehkamper, M.; Wombacher, F.; Mezger, K.; Wiechert, U.

    2002-12-01

    Isotope fractionation laws relate the isotope fractionation factor αA of one isotope ratio to the fractionation factor αB of a second isotope ratio of the same element with a fractionation exponent β, such that αA = αBβ. In a recent paper, Young et al. (GCA 66, 1095-1104 (2002)) inferred that kinetic and equilibrium isotope fractionations are characterized by different mass functions, such that βkin is not equal to βeq. As a consequence, kinetic isotope fractionation is expected to produce fractionation lines in three isotope space that are different from those generated by equilibrium fractionation processes. Young et al. furthermore stated that the variability in mass-dependent fractionation laws may be sufficient to account for the negative Δ17O of tropospheric O2 and the Δ17O anomalies of minerals in SNC meteorites. Such variations have otherwise been interpreted as evidence of non-mass dependant isotope fractionations (Luz et al., Nature 400, 547-550 (1999); Farquhar et al., Science 280, 1589-1582 (1998)). In the present study, we investigated the mass-dependence of isotope fractionation by evaluating the results of evaporation experiments that produced very large differences in Cd isotope compositions (up to about 100‰ ). In these experiments, liquid Cd was evaporated into a vacuum at a temperature of about 200°C. The metal residues remaining after evaporation were analyzed for their Cd isotope composition by multiple-collector inductively coupled plasma-mass spectrometry (MC-ICPMS) relative to the unfractionated starting material. The precision of the measurements is sufficient to clearly distinguish between different fractionation mechanisms. In linearized three-isotope space, the residual Cd metals plot on fractionation lines (e.g., with a slope β = 2.049 +/- 2 for 106}Cd/{114Cd vs. 110}Cd/{114Cd) that are intermediate between the kinetic (β = 2.036) and the equilibrium (β = 2.075) fractionation lines. This can be explained by an

  17. Cometary Deuterium

    NASA Astrophysics Data System (ADS)

    Meier, Roland; Owen, Tobias C.

    1999-10-01

    Deuterium fractionations in cometary ices provide important clues to the origin and evolution of comets. Mass spectrometers aboard spaceprobe Giotto revealed the first accurate D/H ratios in the water of Comet 1P/Halley. Ground-based observations of HDO in Comets C/1996 B2 (Hyakutake) and C/1995 O1 (Hale-Bopp), the detection of DCN in Comet Hale-Bopp, and upper limits for several other D-bearing molecules complement our limited sample of D/H measurements. On the basis of this data set all Oort cloud comets seem to exhibit a similar ( {{{D} {{D {H}}} H}} )_{H}_{2} {O}} ratio in H2O, enriched by about a factor of two relative to terrestrial water and approximately one order of magnitude relative to the protosolar value. Oort cloud comets, and by inference also classical short-period comets derived from the Kuiper Belt cannot be the only source for the Earth's oceans. The cometary O/C ratio and dynamical reasons make it difficult to defend an early influx of icy planetesimals from the Jupiter zone to the early Earth. D/H measurements of OH groups in phyllosilicate rich meteorites suggest a mixture of cometary water and water adsorbed from the nebula by the rocky grains that formed the bulk of the Earth may be responsible for the terrestrial D/H. The D/H ratio in cometary HCN is 7 times higher than the value in cometary H2O. Species-dependent D-fractionations occur at low temperatures and low gas densities via ion-molecule or grain-surface reactions and cannot be explained by a pure solar nebula chemistry. It is plausible that cometary volatiles preserved the interstellar D fractionation. The observed D abundances set a lower limit to the formation temperature of (30 ± 10) K. Similar numbers can be derived from the ortho-to-para ratio in cometary water, from the absence of neon in cometary ices and the presence of S2. Noble gases on Earth and Mars, and the relative abundance of cometary hydrocarbons place the comet formation temperature near 50 K. So far all cometary

  18. Cometary deuterium.

    PubMed

    Meier, R; Owen, T C

    1999-01-01

    Deuterium fractionations in cometary ices provide important clues to the origin and evolution of comets. Mass spectrometers aboard spaceprobe Giotto revealed the first accurate D/H ratios in the water of Comet 1P/Halley. Ground-based observations of HDO in Comets C/1996 B2 (Hyakutake) and C/1995 O1 (Hale-Bopp), the detection of DCN in Comet Hale-Bopp, and upper limits for several other D-bearing molecules complement our limited sample of D/H measurements. On the basis of this data set all Oort cloud comets seem to exhibit a similar (D/H)H2O ratio in H2O, enriched by about a factor of two relative to terrestrial water and approximately one order of magnitude relative to the protosolar value. Oort cloud comets, and by inference also classical short-period comets derived from the Kuiper Belt cannot be the only source for the Earth's oceans. The cometary O/C ratio and dynamical reasons make it difficult to defend an early influx of icy planetesimals from the Jupiter zone to the early Earth. D/H measurements of OH groups in phyllosilicate rich meteorites suggest a mixture of cometary water and water adsorbed from the nebula by the rocky grains that formed the bulk of the Earth may be responsible for the terrestrial D/H. The D/H ratio in cometary HCN is 7 times higher than the value in cometary H2O. Species-dependent D-fractionations occur at low temperatures and low gas densities via ion-molecule or grain-surface reactions and cannot be explained by a pure solar nebula chemistry. It is plausible that cometary volatiles preserved the interstellar D fractionation. The observed D abundances set a lower limit to the formation temperature of (30 +/- 10) K. Similar numbers can he derived from the ortho-to-para ratio in cometary water, from the absence of neon in cometary ices and the presence of S2. Noble gases on Earth and Mars, and the relative abundance of cometary hydrocarbons place the comet formation temperature near 50 K. So far all cometary D/H measurements refer to

  19. Velocity-dependent isotope fractionation in secondary-ion emission

    SciTech Connect

    Gnaser, H.; Hutcheon, I.D.

    1987-01-15

    The formation of secondary ions is subject to isotopic fractionation (differing ionization probabilities for two isotopes) that depends linearly on the inverse velocity of the ejected ions. Theoretically, such a correlation follows directly from an exponential dependence of the ionization probability P on v/sup -1/, Pproportionalexp(-v/sub 0//v). The parameter v/sub 0/, derived from the experiment, amounts to --2 x 10/sup 6/ cm/sec for B, Si, and Ca ions.

  20. FROM PRESTELLAR TO PROTOSTELLAR CORES. II. TIME DEPENDENCE AND DEUTERIUM FRACTIONATION

    SciTech Connect

    Aikawa, Y.; Wakelam, V.; Hersant, F.; Garrod, R. T.; Herbst, E.

    2012-11-20

    We investigate the molecular evolution and D/H abundance ratios that develop as star formation proceeds from a dense molecular cloud core to a protostellar core, by solving a gas-grain reaction network applied to a one-dimensional radiative hydrodynamic model with infalling fluid parcels. Spatial distributions of gas and ice-mantle species are calculated at the first-core stage, and at times after the birth of a protostar. Gas-phase methanol and methane are more abundant than CO at radii r {approx}< 100 AU in the first-core stage, but gradually decrease with time, while abundances of larger organic species increase. The warm-up phase, when complex organic molecules are efficiently formed, is longer-lived for those fluid parcels infalling at later stages. The formation of unsaturated carbon chains (warm carbon-chain chemistry) is also more effective in later stages; C{sup +}, which reacts with CH{sub 4} to form carbon chains, increases in abundance as the envelope density decreases. The large organic molecules and carbon chains are strongly deuterated, mainly due to high D/H ratios in the parent molecules, determined in the cold phase. We also extend our model to simulate simply the chemistry in circumstellar disks, by suspending the one-dimensional infall of a fluid parcel at constant disk radii. The species CH{sub 3}OCH{sub 3} and HCOOCH{sub 3} increase in abundance in 10{sup 4}-10{sup 5} yr at the fixed warm temperature; both also have high D/H ratios.

  1. Temperature Dependence of Carbon Isotope Fractionation in CAM Plants.

    PubMed

    Deleens, E; Treichel, I; O'leary, M H

    1985-09-01

    The carbon isotope fractionation associated with nocturnal malic acid synthesis in Kalanchoë daigremontiana and Bryophyllum tubiflorum was calculated from the isotopic composition of carbon-4 of malic acid, after appropriate corrections. In the lowest temperature treatment (17 degrees C nights, 23 degrees C days), the isotope fractionation for both plants is -4 per thousand (that is, malate is enriched in (13)C relative to the atmosphere). For K. daigremontiana, the isotope fractionation decreases with increasing temperature, becoming approximately 0 per thousand at 27 degrees C/33 degrees C. Detailed analysis of temperature effects on the isotope fractionation indicates that stomatal aperture decreases with increasing temperature and carboxylation capacity increases. For B. tubiflorum, the temperature dependence of the isotope fractionation is smaller and is principally attributed to the normal temperature dependences of the rates of diffusion and carboxylation steps. The small change in the isotopic composition of remaining malic acid in both species which is observed during deacidification indicates that malate release, rather than decarboxylation, is rate limiting in the deacidification process. PMID:16664371

  2. Does the obscured AGN fraction really depend on luminosity?

    NASA Astrophysics Data System (ADS)

    Sazonov, S.; Churazov, E.; Krivonos, R.

    2015-12-01

    We use a sample of 151 local non-blazar active galactic nuclei (AGN) selected from the INTEGRAL all-sky hard X-ray survey to investigate if the observed declining trend of the fraction of obscured (i.e. showing X-ray absorption) AGN with increasing luminosity is mostly an intrinsic or selection effect. Using a torus-obscuration model, we demonstrate that in addition to negative bias, due to absorption in the torus, in finding obscured AGN in hard X-ray flux-limited surveys, there is also positive bias in finding unobscured AGN, due to Compton reflection in the torus. These biases can be even stronger taking into account plausible intrinsic collimation of hard X-ray emission along the axis of the obscuring torus. Given the AGN luminosity function, which steepens at high luminosities, these observational biases lead to a decreasing observed fraction of obscured AGN with increasing luminosity even if this fraction has no intrinsic luminosity dependence. We find that if the central hard X-ray source in AGN is isotropic, the intrinsic (i.e. corrected for biases) obscured AGN fraction still shows a declining trend with luminosity, although the intrinsic obscured fraction is significantly larger than the observed one: the actual fraction is larger than ˜85 per cent at L ≲ 1042.5 erg s-1 (17-60 keV), and decreases to ≲60 per cent at L ≳ 1044 erg s-1. In terms of the half-opening angle θ of an obscuring torus, this implies that θ ≲ 30° in lower luminosity AGN, and θ ≳ 45° in higher luminosity ones. If, however, the emission from the central supermassive black hole is collimated as dL/dΩ ∝ cos α, the intrinsic dependence of the obscured AGN fraction is consistent with a luminosity-independent torus half-opening angle θ ˜ 30°.

  3. Microbial mass-dependent fractionation of chromium isotopes

    USGS Publications Warehouse

    Sikora, E.R.; Johnson, T.M.; Bullen, T.D.

    2008-01-01

    Mass-dependent fractionation of Cr isotopes occurs during dissimilatory Cr(VI) reduction by Shewanella oneidensis strain MR-1. Cells suspended in a simple buffer solution, with various concentrations of lactate or formate added as electron donor, reduced 5 or 10 ??M Cr(VI) to Cr(III) over days to weeks. In all nine batch experiments, 53Cr/52Cr ratios of the unreacted Cr(VI) increased as reduction proceeded. In eight experiments covering a range of added donor concentrations up to 100 ??M, isotopic fractionation factors were nearly invariant, ranging from 1.0040 to 1.0045, with a mean value somewhat larger than that previously reported for abiotic Cr(VI) reduction (1.0034). One experiment containing much greater donor concentration (10 mM lactate) reduced Cr(VI) much faster and exhibited a lesser fractionation factor (1.0018). These results indicate that 53Cr/52Cr measurements should be effective as indicators of Cr(VI) reduction, either bacterial or abiotic. However, variability in the fractionation factor is poorly constrained and should be studied for a variety of microbial and abiotic reduction pathways. ?? 2008 Elsevier Ltd.

  4. Nuclear Volume-Dependent Fractionation of Uranium Isotopes

    NASA Astrophysics Data System (ADS)

    Weyer, S.; Schauble, E. A.; Anbar, A. D.

    2007-12-01

    fractionation in these sediments is opposite in direction to what would be expected from mass-dependent equilibrium or kinetic/diffusive isotope fractionation. Instead, heavy U isotope compositions of reduced U species are expected from first-principles quantum chemical modeling of fractionation driven by nuclear volume. Our modeling results predict that equilibrium nuclear volume and mass-dependent isotope fractionation operate in opposite directions for U, and that the volume effect is of greater magnitude. Combining our observations on natural samples with the results of theoretical modeling strongly indicates that nuclear volume-, rather than mass-dependent isotope fractionation is the dominant process that fractionates the isotope composition of some very heavy elements, such as U, in nature.

  5. Alpha-tocopherol disappearance rates from plasma depend on lipid concentrations: Studies using deuterium labeled collard greens in younger and older adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about alpha-tocopherol's bioavailability as a constituent of food or its dependence on a subject's age. To evaluate the alpha-tocopherol bioavailability from food, we used collard greens grown in deuterated water (2H collard greens) as a source of deuterium-labeled (2H) alpha-tocophe...

  6. THE DEUTERIUM-BURNING MASS LIMIT FOR BROWN DWARFS AND GIANT PLANETS

    SciTech Connect

    Spiegel, David S.; Burrows, Adam; Milsom, John A. E-mail: burrows@astro.princeton.edu

    2011-01-20

    There is no universally acknowledged criterion to distinguish brown dwarfs from planets. Numerous studies have used or suggested a definition based on an object's mass, taking the {approx}13 Jupiter mass (M{sub J} ) limit for the ignition of deuterium. Here, we investigate various deuterium-burning masses for a range of models. We find that, while 13 M{sub J} is generally a reasonable rule of thumb, the deuterium fusion mass depends on the helium abundance, the initial deuterium abundance, the metallicity of the model, and on what fraction of an object's initial deuterium abundance must combust in order for the object to qualify as having burned deuterium. Even though, for most proto-brown dwarf conditions, 50% of the initial deuterium will burn if the object's mass is {approx}(13.0 {+-} 0.8) M{sub J} , the full range of possibilities is significantly broader. For models ranging from zero-metallicity to more than three times solar metallicity, the deuterium-burning mass ranges from {approx}11.0 M{sub J} (for three times solar metallicity, 10% of initial deuterium burned) to {approx}16.3 M{sub J} ( for zero metallicity, 90% of initial deuterium burned).

  7. Tokamak power reactor ignition and time dependent fractional power operation

    SciTech Connect

    Vold, E.L.; Mau, T.K.; Conn, R.W.

    1986-06-01

    A flexible time-dependent and zero-dimensional plasma burn code with radial profiles was developed and employed to study the fractional power operation and the thermal burn control options for an INTOR-sized tokamak reactor. The code includes alpha thermalization and a time-dependent transport loss which can be represented by any one of several currently popular scaling laws for energy confinement time. Ignition parameters were found to vary widely in density-temperature (n-T) space for the range of scaling laws examined. Critical ignition issues were found to include the extent of confinement time degradation by alpha heating, the ratio of ion to electron transport power loss, and effect of auxiliary heating on confinement. Feedback control of the auxiliary power and ion fuel sources are shown to provide thermal stability near the ignition curve.

  8. Species-dependent silicon isotope fractionation by marine diatoms

    NASA Astrophysics Data System (ADS)

    Sutton, Jill N.; Varela, Diana E.; Brzezinski, Mark A.; Beucher, Charlotte P.

    2013-03-01

    Fractionation of silicon (Si) isotopes was measured in seven species (nine strains) of polar and sub-polar marine diatoms grown in semi-continuous unialgal cultures under optimal irradiance and temperature for each diatom strain. Results from this work provide the first evidence that Si isotope fractionation by diatoms is species-dependent. The greatest difference in the Si isotope fractionation factor (ɛ) was observed between two Southern Ocean diatoms, Fragilariopsis kerguelensis (-0.54‰, average for two strains) and Chaetoceros brevis (-2.09‰). The ɛ for the other species, both polar and sub-polar, ranged from -0.72‰ to -1.21‰. The two remaining polar diatoms had ɛ values of -0.74 ± 0.05‰ for Thalassiosira antarctica, and -1.21 ± 0.04‰ for Thalassiosira nordenskioeldii, while the sub-polar species had ɛ values of -0.72 ± 0.04‰ for Thalassiosira weissflogii, -0.88 ± 0.06‰ for Thalassiosira pseudonana (CCCM58), -0.97 ± 0.14‰ for Thalassiosira pseudonana (CCMP1014), and -1.15 ± 0.03‰ for Porosira glacialis. The range in ɛ for the diatoms evaluated in this study may be large enough to significantly impact the Si isotope composition measured in diatom opal (δ30Si-bSiO2) from marine sediments and its subsequent interpretation. To test the influence of diatom taxonomic composition on δ30Si-bSiO2, we developed a model that considered the relative abundance of diatom species and the ɛ values (from this study) for each species present within the sediment core (i.e. weighted-average ɛ). The model was applied to records from a Southern Ocean sediment core (TN057-13) where both diatom abundance and δ30Si-bSiO2 data were available. The analysis indicated that 67% of the variation in δ30Si-bSiO2 could be explained by species-dependent Si isotope fractionation. We suggest that future work should assess phytoplankton taxonomic composition when using δ30Si-bSiO2 as a proxy for Si utilization.

  9. In situ deuterium observation in deuterium-implanted tungsten

    NASA Astrophysics Data System (ADS)

    Furuta, Yoshinori; Takagi, Ikuji; Kawamura, Shotaro; Yamamichi, Kazuyoshi; Akiyoshi, Masafumi; Sasaki, Takayuki; Kobayashi, Taishi

    2013-11-01

    In order to evaluate the tritium inventory in plasma-facing tungsten components of a fusion reactor, deuterium depth profiles in tungsten were observed in situ using nuclear reaction analysis (NRA) under continuous implantation of 3 keV D ions. Measurements were conducted at temperatures of 384, 473, 573 and 673 K. Recombination coefficients and rate constants for the surface recombination process were estimated from the observed deuterium concentration. It is indicated that the measured surface recombination rate constant is applied in a case wherein tungsten is exposed to hydrogen particles of various energies from a fusion plasma. The measured recombination coefficient was identical to that found by a different technique in a previous work. Deuterium in trap sites was found to contribute to deuterium retention in the samples as well as to deuterium in solution sites. The deuterium retention was low in the 384 K sample, in which trap sites had not appeared. Deuterium retention was very low in the 673 K sample, where most deuterium atoms were detrapped and desorbed. At an intermediate temperature of 473 K, the retention showed a maximum value due to a large occupancy of deuterium over many trap sites. The dependence of the retention on deuterium fluence was explained assuming that trap sites were produced by implantation.

  10. Hydrogen–Deuterium Exchange and Mass Spectrometry Reveal the pH-Dependent Conformational Changes of Diphtheria Toxin T Domain

    PubMed Central

    2015-01-01

    The translocation (T) domain of diphtheria toxin plays a critical role in moving the catalytic domain across the endosomal membrane. Translocation/insertion is triggered by a decrease in pH in the endosome where conformational changes of T domain occur through several kinetic intermediates to yield a final trans-membrane form. High-resolution structural studies are only applicable to the static T-domain structure at physiological pH, and studies of the T-domain translocation pathway are hindered by the simultaneous presence of multiple conformations. Here, we report the application of hydrogen–deuterium exchange mass spectrometry (HDX-MS) for the study of the pH-dependent conformational changes of the T domain in solution. Effects of pH on intrinsic HDX rates were deconvolved by converting the on-exchange times at low pH into times under our “standard condition” (pH 7.5). pH-Dependent HDX kinetic analysis of T domain clearly reveals the conformational transition from the native state (W-state) to a membrane-competent state (W+-state). The initial transition occurs at pH 6 and includes the destabilization of N-terminal helices accompanied by the separation between N- and C-terminal segments. The structural rearrangements accompanying the formation of the membrane-competent state expose a hydrophobic hairpin (TH8–9) to solvent, prepare it to insert into the membrane. At pH 5.5, the transition is complete, and the protein further unfolds, resulting in the exposure of its C-terminal hydrophobic TH8–9, leading to subsequent aggregation in the absence of membranes. This solution-based study complements high resolution crystal structures and provides a detailed understanding of the pH-dependent structural rearrangement and acid-induced oligomerization of T domain. PMID:25290210

  11. Pressure dependence of the deuterium isotope effect in the photolysis of formaldehyde by ultraviolet light

    NASA Astrophysics Data System (ADS)

    Nilsson, E. J. K.; Andersen, V. F.; Skov, H.; Johnson, M. S.

    2010-04-01

    The pressure dependence of the relative photolysis rate of HCHO vs. HCDO has been investigated for the first time, using a photochemical reactor at the University of Copenhagen. The dissociation of HCHO vs. HCDO using a UVA lamp was measured at total bath gas pressures of 50, 200, 400, 600 and 1030 mbar. The products of formaldehyde photodissociation are either H2 + CO (molecular channel) or HCO + H (radical channel), and a photolysis lamp was chosen to emit light at wavelengths that greatly favor the molecular channel. The isotope effect in the dissociation, kHCHO/kHCDO, was found to depend strongly on pressure, varying from 1.1 + 0.15/-0.1 at 50 mbar to 1.75±0.10 at 1030 mbar. The results can be corrected for radical channel contribution to yield the kinetic isotope effect for the molecular channel; i.e. the KIE in the production of molecular hydrogen. This is done and the results at 1030 mbar are discussed in relation to previous studies at ambient pressure. In the atmosphere the relative importance of the two product channels changes with altitude as a result of changes in pressure and actinic flux. The study demonstrates that the δD of photochemical hydrogen produced from formaldehyde will increase substantially as pressure decreases.

  12. Deuterium isotope effect on femtosecond solvation dynamics in an ionic liquid microemulsion: an excitation wavelength dependence study.

    PubMed

    Sasmal, Dibyendu Kumar; Mojumdar, Supratik Sen; Adhikari, Aniruddha; Bhattacharyya, Kankan

    2010-04-01

    The deuterium isotope effect on the solvation dynamics and the anisotropy decay of coumarin 480 (C480) in a room temperature ionic liquid (RTIL) microemulsion is studied by femtosecond up-conversion. The microemulsion consists of the RTIL 1-pentyl-3-methyl-imidazolium tetra-fluoroborate ([pmim][BF(4)]) in triton X-100 (TX-100)/benzene. Replacement of H(2)O by D(2)O in the microemulsion causes retardation of solvation dynamics. The average solvation time of C480 (tau(s)) in RTIL microemulsion with 5 wt % D(2)O is approximately 1.5-1.7 times slower compared to that in the H(2)O containing RTIL microemulsion. This suggests that the main species in the microemulsion responsible for solvation is the water molecules. In both D(2)O and H(2)O containing RTIL microemulsion, the solvation dynamics exhibits marked dependence on the excitation wavelength (lambda(ex)) and becomes about 15 times faster as lambda(ex) increases from 375 to 435 nm. This is ascribed to the structural heterogeneity in the RTIL microemulsion. For lambda(ex) = 375 nm, the region near the TX-100 surfactant is probed where bound water molecules cause slow solvation dynamics. At 435 nm, the RTIL pool is selected where the water molecules are more mobile and hence gives rise to faster solvation. The average time constant of anisotropy decay shows opposite dependence on lambda(ex) and increases about 2.5-fold from 180 ps at lambda(ex) = 375 nm to 500 ps at lambda(ex) = 435 nm for D(2)O containing RTIL microemulsion. The slower anisotropy decay at lambda(ex) = 435 nm is ascribed to the higher viscosity of RTIL which causes greater friction at the core. PMID:20235504

  13. DEPENDENCE OF BARRED GALAXY FRACTION ON GALAXY PROPERTIES AND ENVIRONMENT

    SciTech Connect

    Lee, Gwang-Ho; Lee, Myung Gyoon; Park, Changbom; Choi, Yun-Young E-mail: mglee@astro.snu.ac.kr E-mail: yy.choi@khu.ac.kr

    2012-02-01

    We investigate the dependence of the occurrence of bars in galaxies on galaxy properties and environment. We use a volume-limited sample of 33,391 galaxies brighter than M{sub r} = -19.5 + 5logh at 0.02 {<=} z {<=} 0.05489, drawn from the Sloan Digital Sky Survey Data Release 7. We classify the galaxies into early and late types, and identify bars by visual inspection. Among 10,674 late-type galaxies with axis ratio b/a > 0.60, we find 3240 barred galaxies (f{sub bar} = 30.4%) which divide into 2542 strong bars (f{sub SB1} = 23.8%) and 698 weak bars (f{sub SB2} = 6.5%). We find that f{sub SB1} increases as u - r color becomes redder and that it has a maximum value at intermediate velocity dispersion ({sigma} {approx_equal}150 km s{sup -1}). This trend suggests that strong bars are dominantly hosted by intermediate-mass systems. Weak bars prefer bluer galaxies with lower mass and lower concentration. In the case of strong bars, their dependence on the concentration index appears only for massive galaxies with {sigma} > 150 km s{sup -1}. We also find that f{sub bar} does not directly depend on the large-scale background density when other physical parameters (u - r color or {sigma}) are fixed. We discover that f{sub SB1} decreases as the separation to the nearest neighbor galaxy becomes smaller than 0.1 times the virial radius of the neighbor regardless of neighbor's morphology. These results imply that strong bars are likely to be destroyed during strong tidal interactions and that the mechanism for this phenomenon is gravitational and not hydrodynamical. The fraction of weak bars has no correlation with environmental parameters. We do not find any direct evidence for environmental stimulation of bar formation.

  14. α-Tocopherol disappearance rates from plasma depend on lipid concentrations: studies using deuterium-labeled collard greens in younger and older adults1234

    PubMed Central

    Traber, Maret G; Leonard, Scott W; Bobe, Gerd; Fu, Xueyan; Saltzman, Edward; Grusak, Michael A; Booth, Sarah L

    2015-01-01

    Background: Little is known about α-tocopherol’s bioavailability as a constituent of food or its dependence on a subject’s age. Objective: To evaluate the α-tocopherol bioavailability from food, we used collard greens grown in deuterated water (2H collard greens) as a source of deuterium-labeled (2H) α-tocopherol consumed by younger and older adults in a post hoc analysis of a vitamin K study. Design: Younger (mean ± SD age: 32 ± 7 y; n = 12 women and 9 men) and older (aged 67 ± 8 y; n = 8 women and 12 men) adults consumed a test breakfast that included 120 g 2H collard greens (1.2 ± 0.1 mg 2H-α-tocopherol). Plasma unlabeled α-tocopherol and 2H-α-tocopherol were measured by using liquid chromatography–mass spectrometry from fasting (>12 h) blood samples drawn before breakfast (0 h) and at 24, 48, and 72 h and from postprandial samples collected at 4, 5, 6, 7, 9, 12, and 16 h. Results: Times (12.6 ± 2.5 h) of maximum plasma 2H-α-tocopherol concentrations (0.82% ± 0.59% total α-tocopherol), fractional disappearance rates (0.63 ± 0.26 pools/d), half-lives (30 ± 11 h), and the minimum estimated 2H-α-tocopherol absorbed (24% ± 16%) did not vary between age groups or sexes (n = 41). Unlabeled α-tocopherol concentrations were higher in older adults (26.4 ± 8.6 μmol/L) than in younger adults (19.3 ± 4.2 μmol/L; P = 0.0019) and correlated with serum lipids (r = 0.4938, P = 0.0012). In addition, 2H-α-tocopherol half-lives were correlated with lipids (r = 0.4361, P = 0.0044). Conclusions: Paradoxically, α-tocopherol remained in circulation longer in participants with higher serum lipids, but the 2H-α-tocopherol absorbed was not dependent on the plasma lipid status. Neither variable was dependent on age. These data suggest that plasma α-tocopherol concentrations are more dependent on mechanisms that control circulating lipids rather than those related to its absorption and initial incorporation into plasma. This trial was registered at

  15. Chemodynamical Deuterium Fractionation in the Early Solar Nebula: The Origin of Water on Earth and in Asteroids and Comets

    NASA Astrophysics Data System (ADS)

    Albertsson, T.; Semenov, D.; Henning, Th.

    2014-03-01

    Formation and evolution of water in the solar system and the origin of water on Earth constitute one of the most interesting questions in astronomy. The prevailing hypothesis for the origin of water on Earth is by delivery through water-rich small solar system bodies. In this paper, the isotopic and chemical evolution of water during the early history of the solar nebula, before the onset of planetesimal formation, is studied. A gas-grain chemical model that includes multiply deuterated species and nuclear spin-states is combined with a steady-state solar nebula model. To calculate initial abundances, we simulated 1 Myr of evolution of a cold and dark TMC-1-like prestellar core. Two time-dependent chemical models of the solar nebula are calculated over 1 Myr: (1) a laminar model and (2) a model with two-dimensional (2D) turbulent mixing. We find that the radial outward increase of the H2O D/H ratio is shallower in the chemodynamical nebular model than in the laminar model. This is related to more efficient defractionation of HDO via rapid gas-phase processes because the 2D mixing model allows the water ice to be transported either inward and thermally evaporated or upward and photodesorbed. The laminar model shows the Earth water D/H ratio at r <~ 2.5 AU, whereas for the 2D chemodynamical model this zone is larger, r <~ 9 AU. Similarly, the water D/H ratios representative of the Oort-family comets, ~2.5-10 × 10-4, are achieved within ~2-6 AU and ~2-20 AU in the laminar and the 2D model, respectively. We find that with regards to the water isotopic composition and the origin of the comets, the mixing model seems to be favored over the laminar model.

  16. Chemodynamical deuterium fractionation in the early solar nebula: The origin of water on earth and in asteroids and comets

    SciTech Connect

    Albertsson, T.; Semenov, D.; Henning, Th.

    2014-03-20

    Formation and evolution of water in the solar system and the origin of water on Earth constitute one of the most interesting questions in astronomy. The prevailing hypothesis for the origin of water on Earth is by delivery through water-rich small solar system bodies. In this paper, the isotopic and chemical evolution of water during the early history of the solar nebula, before the onset of planetesimal formation, is studied. A gas-grain chemical model that includes multiply deuterated species and nuclear spin-states is combined with a steady-state solar nebula model. To calculate initial abundances, we simulated 1 Myr of evolution of a cold and dark TMC-1-like prestellar core. Two time-dependent chemical models of the solar nebula are calculated over 1 Myr: (1) a laminar model and (2) a model with two-dimensional (2D) turbulent mixing. We find that the radial outward increase of the H{sub 2}O D/H ratio is shallower in the chemodynamical nebular model than in the laminar model. This is related to more efficient defractionation of HDO via rapid gas-phase processes because the 2D mixing model allows the water ice to be transported either inward and thermally evaporated or upward and photodesorbed. The laminar model shows the Earth water D/H ratio at r ≲ 2.5 AU, whereas for the 2D chemodynamical model this zone is larger, r ≲ 9 AU. Similarly, the water D/H ratios representative of the Oort-family comets, ∼2.5-10 × 10{sup –4}, are achieved within ∼2-6 AU and ∼2-20 AU in the laminar and the 2D model, respectively. We find that with regards to the water isotopic composition and the origin of the comets, the mixing model seems to be favored over the laminar model.

  17. Water deuterium fractionation in the high-mass star-forming region G34.26+0.15 based on Herschel/HIFI data

    NASA Astrophysics Data System (ADS)

    Coutens, A.; Vastel, C.; Hincelin, U.; Herbst, E.; Lis, D. C.; Chavarría, L.; Gérin, M.; van der Tak, F. F. S.; Persson, C. M.; Goldsmith, P. F.; Caux, E.

    2014-12-01

    Understanding water deuterium fractionation is important for constraining the mechanisms of water formation in interstellar clouds. Observations of HDO and H_2^{18}O transitions were carried out towards the high-mass star-forming region G34.26+0.15 with the Heterodyne Instrument for the Far-Infrared (HIFI) instrument onboard the Herschel Space Observatory, as well as with ground-based single-dish telescopes. 10 HDO lines and three H_2^{18}O lines covering a broad range of upper energy levels (22-204 K) were detected. We used a non-local thermal equilibrium 1D analysis to determine the HDO/H2O ratio as a function of radius in the envelope. Models with different water abundance distributions were considered in order to reproduce the observed line profiles. The HDO/H2O ratio is found to be lower in the hot core (˜3.5 × 10-4-7.5 × 10-4) than in the colder envelope (˜1.0 × 10-3-2.2 × 10-3). This is the first time that a radial variation of the HDO/H2O ratio has been found to occur in a high-mass source. The chemical evolution of this source was modelled as a function of its radius and the observations are relatively well reproduced. The comparison between the chemical model and the observations leads to an age of ˜105 yr after the infrared dark cloud stage.

  18. Temperature and site dependence of the rate of hydrogen and deuterium abstraction by methyl radicals in methanol glasses

    SciTech Connect

    Doba, T.; Ingold, K.U.; Siebrand, W.; Wildman, T.A.

    1984-07-19

    Rate constants are reported for hydrogen and deuterium abstraction by methyl radicals in CH/sub 3/OH and CD/sub 3/OD glasses in the ranges 5-89 and 77-97 K, respectively. At each temperature, they show a distribution due to a variation of radical trapping sites. The rate constants of this distribution are analyzed theoretically to yield a quantitative relation between tunneling rate and equilibrium tunneling distance. 20 references, 2 figures.

  19. THE ENVIRONMENTAL DEPENDENCE OF THE EVOLVING S0 FRACTION

    SciTech Connect

    Just, Dennis W.; Zaritsky, Dennis; Sand, David J.; Desai, Vandana; Rudnick, Gregory

    2010-03-01

    We re-investigate the dramatic rise in the S0 fraction, f{sub S0}, within clusters since z {approx} 0.5. In particular, we focus on the role of the global galaxy environment on f{sub S0} by compiling, either from our own observations or the literature, robust line-of-sight velocity dispersions, sigma's, for a sample of galaxy groups and clusters at 0.1 < z < 0.8 that have uniformly determined, published morphological fractions. We find that the trend of f{sub S0} with redshift is twice as strong for sigma < 750 km s{sup -1} groups/poor clusters than for higher-sigma, rich clusters. From this result, we infer that over this redshift range galaxy-galaxy interactions, which are more effective in lower-sigma environments, are more responsible for transforming spiral galaxies into S0's than galaxy-environment processes, which are more effective in higher-sigma environments. The rapid, recent growth of the S0 population in groups and poor clusters implies that large numbers of progenitors exist in low-sigma systems at modest redshifts ({approx}0.5), where morphologies and internal kinematics are within the measurement range of current technology.

  20. Astration of cosmological deuterium

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1985-01-01

    Attention is given to the degree of primordial deuterium's astration through the continuous galactic processes of star formation and chemical evolution. Exact analytic solutions are given for galactic chemical evolution when infall of constant composition occurs at a rate, f(t), which is presently defined. Solutions are given for the linear model with instantaneous recycling and with constant return fraction R. The results suggest that big bang D/H was at least three times larger than the largest values observed in today's solar neighborhood, and even larger if matter falling into the disk is already astrated.

  1. Experimental investigation of mass-dependent and mass-independent fractionation of mercury isotopes

    NASA Astrophysics Data System (ADS)

    Bergquist, B. A.; Blum, J. D.; Marcus, J. W.; Biswas, A.

    2006-12-01

    Mercury is a globally distributed and highly toxic pollutant, the mobility and bioaccumulation of which is highly dependent on its redox cycling. With seven isotopes (including two odd-mass isotopes) and a relative mass difference of 4%, stable isotope fractionation of Hg could be a powerful tool to track and understand Hg cycling in the environment. Ongoing studies of natural mercury isotope variations in ore deposits, hydrothermal fluids, sediments, soils, fish tissues and bacterial cultures have documented a measurable range in Hg isotopes of up to ~5‰ in the ^{202}Hg/^{198}Hg ratio with most samples displaying mass-dependent fractionation. A small, but growing, body of data also suggests that natural samples display mass-independent fractionation of Hg isotopes. In this study, we explore mechanisms that lead to both mass- dependent and mass-independent fractionation of Hg isotopes. Isotope ratios were measured by continuous- flow cold-vapor generation coupled to MC-ICPMS with an external precision of ±0.1‰ (2SD). We observe three distinct types of isotope fractionation for Hg: (1) mass-dependent fractionation, (2) mass- independent fractionation of odd isotopes concurrent with mass-dependent fractionation of even isotopes, and (3) mass-independent fractionation of all Hg isotopes. Reduction of Hg species to Hg(0) vapor is an important mechanism for removal of Hg from aqueous systems into the atmosphere. Reduction of Hg occurs through numerous pathways including photoreduction, abiotic organic reduction, and biological reduction. We find that photoreduction of Hg(II) by natural sunlight leads to mass-independent fractionation of the odd isotopes (^{201}Hg, ^{199}Hg) with several permil deviations from predicted mass dependence, and mass- dependent fractionation of the even isotopes. In contrast, both biological reduction (Kritee et al., 2006) and dark abiotic organically mediated reduction follow mass-dependent fractionation of even and odd isotopes

  2. Pressure-dependent boron isotopic fractionation observed by column chromatography

    NASA Astrophysics Data System (ADS)

    Musashi, M.; Oi, T.; Matsuo, M.; Nomura, M.

    2007-12-01

    Boron isotopic fractionation factor ( S ) between boron taken up in strongly basic anion exchange resin and boron in aqueous solution was determined by breakthrough column chromatography at 5 and 17 MPa at 25°C, using 0.1 mmol/L boric acid solution as feed solution. The S values obtained were 1.018 and 1.012, respectively, which were smaller than the value reported by using the same chromatographic method at atmospheric pressure at 25°C with the boron concentration of 10 mmol/L, but were larger than the values at the same condition with much higher concentration of 100 and 501 mmol/L, indicating that borate-polymerization reducing the isotopic fractionation was negligible. However, calculations based on the theory of isotope distribution between two phases estimated that 21% (5MPa) and 47% (17MPa) of boron taken up in the resin phase was in the three-coordinated B(OH)3-form, instead of in the four-coordinated B(OH)4--form, at high pressures even with the very diluted solution. We discussed this discrepancy by introducing (1) hydration or (2) a partial molar volume difference between isotopic molecules. It was inferred that borate ions were partially dehydrated upon transfer from the solution phase to the resin phase at high pressures, which resulted in smaller S values compared with those at the atmospheric pressure. Alternatively, it was likely that the S value decreased with increasing pressure, because the difference of the partial isotopic molar volumes between 10B(OH)3 and 11B(OH)3 was larger than that between 10B(OH)4- and 11B(OH)4-. If either will be the case, the influence of a pressure upon the isotope effect may not be negligible for boron isotopic exchange equilibrium. This knowledge is crucial for the principle of the boron isotopic pH-metry reconstructing a chemical variation at the paleo-deep oceanic environment where the early life may have been evolved.

  3. Deuterium enrichment of interstellar dusts

    NASA Astrophysics Data System (ADS)

    Das, Ankan; Chakrabarti, Sandip Kumar; Majumdar, Liton; Sahu, Dipen

    2016-07-01

    High abundance of some abundant and simple interstellar species could be explained by considering the chemistry that occurs on interstellar dusts. Because of its simplicity, the rate equation method is widely used to study the surface chemistry. However, because the recombination efficiency for the formation of any surface species is highly dependent on various physical and chemical parameters, the Monte Carlo method is best suited for addressing the randomness of the processes. We carry out Monte-Carlo simulation to study deuterium enrichment of interstellar grain mantle under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud regions, very strong radiation fields persists and hardly a few layers of surface species are formed. In translucent cloud regions with a moderate radiation field, significant number of layers would be produced and surface coverage is mainly dominated by photo-dissociation products such as, C, CH_3, CH_2D, OH and OD. In the intermediate dense cloud regions (having number density of total hydrogen nuclei in all forms ˜2 × 10^4 cm^{-3}), water and methanol along with their deuterated derivatives are efficiently formed. For much higher density regions (˜10^6 cm^{-3}), water and methanol productions are suppressed but surface coverage of CO, CO_2, O_2, O_3 are dramatically increased. We find a very high degree of fractionation of water and methanol. Observational results support a high fractionation of methanol but surprisingly water fractionation is found to be low. This is in contradiction with our model results indicating alternative routes for de-fractionation of water.

  4. Mass-dependent and -independent fractionation of isotopes in Ni and Pb chelate complex formation reactions

    NASA Astrophysics Data System (ADS)

    Nomura, Masao; Kudo, Takashi; Adachi, Atsuhiko; Aida, Masao; Fujii, Yasuhiko

    2013-11-01

    Mass independent fractionation (MIF) has been a very interesting topic in the field of inorganic isotope chemistry, in particular, geo- and cosmo- chemistry. In the present work, we studied the isotope fractionation of Ni(II) and Pb(II) ions in complex formation with chelating reagent EDTA. To obtain clear results on the mass dependence of the isotope fractionation, we have conducted long-distance ion exchange chromatography of Ni(II) and Pb(II), using chelate complex reagent EDTA. The results apparently show that the isotope fractionation in Ni complex formation system is governed by the mass dependent rule. On the other hand the isotope fractionation in the Pb complex system is governed by the mass independent rule or the nuclear volume effect.

  5. State-dependent switching control of switched positive fractional-order systems.

    PubMed

    Zhao, Xudong; Yin, Yunfei; Zheng, Xiaolong

    2016-05-01

    In this paper, the problem of switching stabilization for a class of continuous-time switched positive fractional-order systems is studied by using state-dependent switching. First, the asymptotic stability condition of switched positive fractional-order systems with state-dependent switching is given, which is based on the fractional co-positive Lyapunov method. Moreover, by the sliding sector method, the stability condition of switched positive fractional-order systems whose subsystems are possibly all unstable is obtained. A variable structure (VS) switching law with sliding sector is also proposed to guarantee the switched positive fractional-order system to be asymptotically stable. Finally, two numerical examples are given to demonstrate the advantages and effectiveness of our developed results. PMID:26922493

  6. Mass-dependent and -independent fractionation of isotopes in Ni and Pb chelate complex formation reactions

    SciTech Connect

    Nomura, Masao; Kudo, Takashi; Adachi, Atsuhiko; Aida, Masao; Fujii, Yasuhiko

    2013-11-13

    Mass independent fractionation (MIF) has been a very interesting topic in the field of inorganic isotope chemistry, in particular, geo- and cosmo- chemistry. In the present work, we studied the isotope fractionation of Ni(II) and Pb(II) ions in complex formation with chelating reagent EDTA. To obtain clear results on the mass dependence of the isotope fractionation, we have conducted long-distance ion exchange chromatography of Ni(II) and Pb(II), using chelate complex reagent EDTA. The results apparently show that the isotope fractionation in Ni complex formation system is governed by the mass dependent rule. On the other hand the isotope fractionation in the Pb complex system is governed by the mass independent rule or the nuclear volume effect.

  7. Volume fraction dependent magnetic behaviour of ferrofluids for rotating seal applications

    NASA Astrophysics Data System (ADS)

    Schinteie, G.; Palade, P.; Vekas, L.; Iacob, N.; Bartha, C.; Kuncser, V.

    2013-10-01

    Ferrofluid samples consisting of magnetite nanoparticles (NPs) coated with oleic acid and dispersed in a non-polar organic solvent have been synthesized by chemical routes. Different volume fractions, φ, of magnetic NPs were considered. The overall structural characterization of NPs has been performed by x-ray diffractometry, with lattice parameters and average coherence lengths evaluated via Rietveld refinements. The magnetic properties of different samples have been analysed by SQUID magnetometry and temperature-dependent Mössbauer spectroscopy and finally explained by adequate magnetic relaxation mechanisms. Zero field cooling-field cooling protocols provided useful information about specific volume fraction dependent magnetic relaxation and de-freezing processes, the lack of the Verwey transition and stronger dipolar interactions at higher volume fractions. Anisotropy energies as obtained by both temperature dependent Mössbauer spectroscopy and magnetometry data are compared and a new procedure for a quantitative characterization of the dipolar interactions is proposed.

  8. Simulating transient dynamics of the time-dependent time fractional Fokker-Planck systems

    NASA Astrophysics Data System (ADS)

    Kang, Yan-Mei

    2016-09-01

    For a physically realistic type of time-dependent time fractional Fokker-Planck (FP) equation, derived as the continuous limit of the continuous time random walk with time-modulated Boltzmann jumping weight, a semi-analytic iteration scheme based on the truncated (generalized) Fourier series is presented to simulate the resultant transient dynamics when the external time modulation is a piece-wise constant signal. At first, the iteration scheme is demonstrated with a simple time-dependent time fractional FP equation on finite interval with two absorbing boundaries, and then it is generalized to the more general time-dependent Smoluchowski-type time fractional Fokker-Planck equation. The numerical examples verify the efficiency and accuracy of the iteration method, and some novel dynamical phenomena including polarized motion orientations and periodic response death are discussed.

  9. Equilibrium uranium isotope fractionation by nuclear volume and mass-dependent processes

    NASA Astrophysics Data System (ADS)

    Schauble, E. A.

    2006-12-01

    Uranium serves as a geochemical tracer of oxidation near the Earth's surface, and is also the basis for several isotopic geochronometers. It is thus important to understand possible non-radiogenic and non-radioactive isotopic fractionation of uranium in natural systems. This study presents theoretical estimates of equilibrium uranium isotope fractionations in U-bearing molecules and complexes, calculated using first-principles computational chemistry. Ion-exchange experiments (1,2) have indicated that mass-dependent mechanisms, alone, cannot explain 238U/234U and 238U/^{235}U fractionations, so nuclear volume (i.e., field shift) fractionation effects are also considered in theoretical calculations. The results indicate that equilibrium isotopic fractionation is likely when U4+ and U6+ species equilibrate. Nuclear volume fractionation leads to higher 238U/^{235}U in U4+-bearing species, overwhelming a smaller mass- dependent fractionation in the opposite direction. The calculated net fractionation between U(H2O)_94+ and UO2Cl3(H2O)_2^- is approximately 1 per mil at 20-150°C, in agreement with earlier experiments. These results also reproduce the apparent non mass-dependent signature observed in 238U/234U relative to 238U/^{235}U. In addition to redox reactions, significant fractionation is expected between different U6+-bearing uranyl complexes (e.g., UO2(H2O)_52+, UO2(NO3)_3^-, UO2(CO3)(H2O)3). These results suggest that U-isotope composition could be used as a proxy for the oxidation state and speciation of natural waters, and that U-isotope ratios are not constant in materials formed or equilibrated at low temperatures. More generally, nuclear volume fractionations are expected to partially cancel or reverse mass-dependent fractionations caused by redox transitions among the high oxidation states (≥+2) of lanthanides, actinides, and heavy transition elements. References: 1. Nomura, Higuchi and Fujii, 1996, J. Am. Chem. Soc., v. 118, p. 9127-9130. 2. Bigeleisen

  10. Mass dependent isotope fractionation during impacts induced the Archaean mass-independent fractionation of sulphur: Evidence against Great Oxidation Event

    NASA Astrophysics Data System (ADS)

    Huang, H.

    2010-12-01

    A prevailing hypothesis, low-oxygen level of the Archaean atmosphere, relies strongly on the presence of strong mass-independent fractionation (MIF) of the sulfur isotopes in sulfide- and sulfate-bearing minerals older than 2.4 billion years. Actually, there is “a broad overlap between MIF signals observed within Archaean sedimentary sequences and periods of enhanced asteroid impacts represented by impact ejecta/fallout units”(Glikson 2010) (Fig. 1). Moreover, usually MIF- related sulphur occurs in the Archaean sedimentary rocks as pyrite (FeS2) which has been found in the K-T boundary clay beds and in several identified impact craters, which is an independent argument in favor of pyrites could be the product of impact. Impact processes (vaporization and condensation) are sufficient to explain the MIF signals following the principle: the earlier the condensed material, the more enriched in lighter isotopes (Huang 2010). The nature of the MIF of the sulfur isotopes is that the fractionation of isotope is still mass dependent during impacts, which means the measured nonzero Δ33S values of Archean sulfide- and sulfate-bearing minerals indicate that their different condensation sequences. Another important line of evidence that support the impact-generated MIF of the sulfur isotopes comes from the various iron isotope values of the pyrites especially those with iron isotope heterogeneity at grain scale. Thus, it is clear that the signals are the markers of impact rather than O2 poor atmosphere. Furthermore, this can also account for the lack of MIF-S in several Archaean units before 2.4 billion years. Figure 1 Plot of mass-independent fractionation of sulphur and asteroid impact events with age. Modified from Glikson (2010)

  11. Correcting the initialization of models with fractional derivatives via history-dependent conditions

    NASA Astrophysics Data System (ADS)

    Du, Maolin; Wang, Zaihua

    2016-04-01

    Fractional differential equations are more and more used in modeling memory (history-dependent, non-local, or hereditary) phenomena. Conventional initial values of fractional differential equations are defined at a point, while recent works define initial conditions over histories. We prove that the conventional initialization of fractional differential equations with a Riemann-Liouville derivative is wrong with a simple counter-example. The initial values were assumed to be arbitrarily given for a typical fractional differential equation, but we find one of these values can only be zero. We show that fractional differential equations are of infinite dimensions, and the initial conditions, initial histories, are defined as functions over intervals. We obtain the equivalent integral equation for Caputo case. With a simple fractional model of materials, we illustrate that the recovery behavior is correct with the initial creep history, but is wrong with initial values at the starting point of the recovery. We demonstrate the application of initial history by solving a forced fractional Lorenz system numerically.

  12. Correcting the initialization of models with fractional derivatives via history-dependent conditions

    NASA Astrophysics Data System (ADS)

    Du, Maolin; Wang, Zaihua

    2015-08-01

    Fractional differential equations are more and more used in modeling memory (history-dependent, non-local, or hereditary) phenomena. Conventional initial values of fractional differential equations are defined at a point, while recent works define initial conditions over histories. We prove that the conventional initialization of fractional differential equations with a Riemann-Liouville derivative is wrong with a simple counter-example. The initial values were assumed to be arbitrarily given for a typical fractional differential equation, but we find one of these values can only be zero. We show that fractional differential equations are of infinite dimensions, and the initial conditions, initial histories, are defined as functions over intervals. We obtain the equivalent integral equation for Caputo case. With a simple fractional model of materials, we illustrate that the recovery behavior is correct with the initial creep history, but is wrong with initial values at the starting point of the recovery. We demonstrate the application of initial history by solving a forced fractional Lorenz system numerically.

  13. Molecular weight dependence of segmental alignment in a sheared polymer melt: A deuterium nuclear magnetic resonance investigation

    NASA Astrophysics Data System (ADS)

    Cormier, Ryan J.; Callaghan, Paul T.

    2002-06-01

    2H NMR quadrupole interaction spectroscopy has been used to measure the molecular weight dependence of poly(dimethylsiloxane) chain deformation under shear in a cylindrical Couette cell while NMR velocimetry has been used to directly measure shear rates. The signals were acquired from a perdeuterated benzene probe molecule, which provides a motionally averaged sampling of the entire segmental ensemble. We have measured the dependence on shear rate of the SXX (velocity), SYY (velocity gradient), and SZZ (vorticity) elements of the segmented alignment tensor, fitting the data using the standard Doi-Edwards theory and modified to allow for convected constraint release. Our results suggest that the tube disengagement times scale as molecular weight to the power 3.5±0.1, consistent with the usual 3.4 power law. Our velocimetry measurements indicate a reproducible and consistent slip occurring at high molecular weights (>1 M Dalton), a phenomenon which is independently observed in a lower than expected chain deformation.

  14. Hydrogen/Deuterium Exchange Kinetics Demonstrate Long Range Allosteric Effects of Thumb Site 2 Inhibitors of Hepatitis C Viral RNA-dependent RNA Polymerase.

    PubMed

    Deredge, Daniel; Li, Jiawen; Johnson, Kenneth A; Wintrode, Patrick L

    2016-05-01

    New nonnucleoside analogs are being developed as part of a multi-drug regimen to treat hepatitis C viral infections. Particularly promising are inhibitors that bind to the surface of the thumb domain of the viral RNA-dependent RNA polymerase (NS5B). Numerous crystal structures have been solved showing small molecule non-nucleoside inhibitors bound to the hepatitis C viral polymerase, but these structures alone do not define the mechanism of inhibition. Our prior kinetic analysis showed that nonnucleoside inhibitors binding to thumb site-2 (NNI2) do not block initiation or elongation of RNA synthesis; rather, they block the transition from the initiation to elongation, which is thought to proceed with significant structural rearrangement of the enzyme-RNA complex. Here we have mapped the effect of three NNI2 inhibitors on the conformational dynamics of the enzyme using hydrogen/deuterium exchange kinetics. All three inhibitors rigidify an extensive allosteric network extending >40 Å from the binding site, thus providing a structural rationale for the observed disruption of the transition from distributive initiation to processive elongation. The two more potent inhibitors also suppress slow cooperative unfolding in the fingers extension-thumb interface and primer grip, which may contribute their stronger inhibition. These results establish that NNI2 inhibitors act through long range allosteric effects, reveal important conformational changes underlying normal polymerase function, and point the way to the design of more effective allosteric inhibitors that exploit this new information. PMID:27006396

  15. A strong redshift dependence of the broad absorption line quasar fraction

    NASA Astrophysics Data System (ADS)

    Allen, James T.; Hewett, Paul C.; Maddox, Natasha; Richards, Gordon T.; Belokurov, Vasily

    2011-01-01

    We describe the application of non-negative matrix factorization to generate compact reconstructions of quasar spectra from the Sloan Digital Sky Survey (SDSS), with particular reference to broad absorption line quasars (BALQSOs). BAL properties are measured for Si IVλ1400, C IVλ1550, Al IIIλ1860 and Mg IIλ2800, resulting in a catalogue of 3547 BALQSOs. Two corrections, based on extensive testing of synthetic BALQSO spectra, are applied in order to estimate the intrinsic fraction of C IV BALQSOs. First, the probability of an observed BALQSO spectrum being identified as such by our algorithm is calculated as a function of redshift, signal-to-noise ratio and BAL properties. Secondly, the different completenesses of the SDSS target selection algorithm for BALQSOs and non-BAL quasars are quantified. Combining the detection probabilities with an intrinsic E(B-V) distribution capable of reproducing the observed increase in mean E(B-V) with increasing redshift, the intrinsic C IV BALQSO fraction is 41 ± 5 per cent. Our analysis of the selection effects allows us to measure the dependence of the intrinsic C IV BALQSO fraction on luminosity and redshift. We find a factor of 3.5 ± 0.4 decrease in the intrinsic fraction from the highest redshifts, z≃ 4.0, down to z≃ 2.0. The redshift dependence implies that an orientation effect alone is not sufficient to explain the presence of BAL troughs in some but not all quasar spectra. Our results are consistent with the intrinsic BALQSO fraction having no strong luminosity dependence, although with 3σ limits on the rate of change of the intrinsic fraction with luminosity of -6.9 and 7.0 per cent dex-1 we are unable to rule out such a dependence.

  16. Fractional Green's Function for the Time-Dependent Scattering Problem in the Space-Time-Fractional Quantum Mechanics

    NASA Astrophysics Data System (ADS)

    Dong, Jianping

    2014-12-01

    Integral form of the space-time-fractional Schrödinger equation for the scattering problem in the fractional quantum mechanics is studied in this paper. We define the fractional Green's function for the space-time fractional Schrödinger equation and express it in terms of Fox's H-function and in a computable series form. The asymptotic formula of the Green's function for large argument is also obtained, and applied to study the fractional quantum scattering problem. We get the approximate scattering wave function with correction of every order.

  17. Use and Abuse of a Fractional Fokker-Planck Dynamics for Time-Dependent Driving

    NASA Astrophysics Data System (ADS)

    Heinsalu, E.; Patriarca, M.; Goychuk, I.; Hänggi, P.

    2007-09-01

    We investigate a subdiffusive, fractional Fokker-Planck dynamics occurring in time-varying potential landscapes and thereby disclose the failure of the fractional Fokker-Planck equation (FFPE) in its commonly used form when generalized in an ad hoc manner to time-dependent forces. A modified FFPE (MFFPE) is rigorously derived, being valid for a family of dichotomously alternating force fields. This MFFPE is numerically validated for a rectangular time-dependent force with zero average bias. For this case, subdiffusion is shown to become enhanced as compared to the force free case. We question, however, the existence of any physically valid FFPE for arbitrary varying time-dependent fields that differ from this dichotomous varying family.

  18. Deuterium incorporation into Escherichia coli proteins. A neutron-scattering study of DNA-dependent RNA polymerase.

    PubMed

    Lederer, H; May, R P; Kjems, J K; Schaefer, W; Crespi, H L; Heumann, H

    1986-05-01

    Neutron small-angle scattering studies of single protein subunits in a protein-DNA complex require the adjustment of the neutron scattering-length densities of protein and DNA, which is attainable by specific deuteration of the protein. The neutron scattering densities of unlabelled DNA and DNA-dependent RNA polymerase of Escherichia coli match when RNA polymerase is isolated from cells grown in a medium containing 46% D2O and unlabelled glucose as carbon source. Their contrasts vanish simultaneously in a dialysis buffer containing 65% D2O. An expression was evaluated which allows the calculation of the degree of deuteration and match point of any E. coli protein from the D2O content of the growth medium, taking the 2H incorporation into RNA polymerase amino acids to be representative for all amino acids in E. coli proteins. The small-angle scattering results, on which the calculation of the degree of deuteration is based, were confirmed by mass spectrometric measurements. PMID:3516697

  19. Approximating a Giving Up Smoking Dynamic on Adolescent Nicotine Dependence in Fractional Order

    PubMed Central

    2016-01-01

    In this work, we consider giving up smoking dynamic on adolescent nicotine dependence. First, we use the Caputo derivative to develop the model in fractional order. Then we apply two different numerical methods to compute accurate approximate solutions of this new model in fractional order and compare their results. In order to do this, we consider the generalized Euler method (GEM) and multi-step generalized differential transform method (MSGDTM). We also show the unique positive solution for this model and present numerical results graphically. PMID:27105426

  20. Mass-Dependent and -Independent Fractionation of Hg Isotopes by Photoreduction in Aquatic Systems

    NASA Astrophysics Data System (ADS)

    Bergquist, Bridget A.; Blum, Joel D.

    2007-10-01

    Mercury (Hg) isotopes can be used as tracers of Hg biogeochemical pathways in the environment. The photochemical reduction of aqueous Hg species by natural sunlight leads to both mass-dependent fractionation (MDF) of Hg isotopes and mass-independent fractionation (MIF) of the odd-mass isotopes, with the relation between the MIF for the two odd isotopes being distinct for different photoreduction pathways. Large variations in MDF and MIF are observed in fish and provide new insights into the sources and bioaccumulation of Hg in food webs. MIF in fish can also be used to estimate the loss of methylmercury via photoreduction in aquatic ecosytems.

  1. Approximating a Giving Up Smoking Dynamic on Adolescent Nicotine Dependence in Fractional Order.

    PubMed

    Zeb, Anwar; Zaman, Gul; Erturk, Vedat Suat; Alzalg, Baha; Yousafzai, Faisal; Khan, Madad

    2016-01-01

    In this work, we consider giving up smoking dynamic on adolescent nicotine dependence. First, we use the Caputo derivative to develop the model in fractional order. Then we apply two different numerical methods to compute accurate approximate solutions of this new model in fractional order and compare their results. In order to do this, we consider the generalized Euler method (GEM) and multi-step generalized differential transform method (MSGDTM). We also show the unique positive solution for this model and present numerical results graphically. PMID:27105426

  2. Thermal conductivity of simple liquids: temperature and packing-fraction dependence.

    PubMed

    Ohtori, Norikazu; Ishii, Yoshiki; Togawa, Yoshinori; Oono, Takuya; Takase, Keiichi

    2014-02-01

    The thermal conductivity of rare gases in liquid and dense fluid states has been evaluated using molecular dynamics simulation with the Lennard-Jones (LJ) potentials and the Green-Kubo (GK) formula. All the calculated thermal conductivities are in very good agreement with experimental results for a wide range of temperature and density. Special attention was paid to temperature and packing-fraction dependence which is nontrivial from dimensional analysis on the LJ potentials and the GK formula. First, the temperature dependence of T(1/4) was determined from the calculations at constant densities. Secondly, in order to obtain the dependence on packing fraction from that on number density separately, a scaling method of particle and/or cell size was introduced. The number density dependence of (N/V)(2/3) which is expected from the dimensional analysis of the GK formulas was confirmed and the packing-fraction dependence of η(3/2) was determined by using the scaling method. It turned out that the summarized functional form of m(-1/2)(N/V)(2/3)η(3/2)T(1/4) can well express both the calculated and experimental thermal conductivities for Ar, Kr, and Xe, where m is the atomic mass. The scaling method has also been applied to molten NaCl and KCl so that it has been found that the thermal conductivity has the packing-fraction dependence of η(2/3) which is much weaker than that of the simple LJ liquids. PMID:25353444

  3. Thermal conductivity of simple liquids: Temperature and packing-fraction dependence

    NASA Astrophysics Data System (ADS)

    Ohtori, Norikazu; Ishii, Yoshiki; Togawa, Yoshinori; Oono, Takuya; Takase, Keiichi

    2014-02-01

    The thermal conductivity of rare gases in liquid and dense fluid states has been evaluated using molecular dynamics simulation with the Lennard-Jones (LJ) potentials and the Green-Kubo (GK) formula. All the calculated thermal conductivities are in very good agreement with experimental results for a wide range of temperature and density. Special attention was paid to temperature and packing-fraction dependence which is nontrivial from dimensional analysis on the LJ potentials and the GK formula. First, the temperature dependence of T1/4 was determined from the calculations at constant densities. Secondly, in order to obtain the dependence on packing fraction from that on number density separately, a scaling method of particle and/or cell size was introduced. The number density dependence of (N/V)2/3 which is expected from the dimensional analysis of the GK formulas was confirmed and the packing-fraction dependence of η3/2 was determined by using the scaling method. It turned out that the summarized functional form of m-1/2(N/V)2/3η3/2T1/4 can well express both the calculated and experimental thermal conductivities for Ar, Kr, and Xe, where m is the atomic mass. The scaling method has also been applied to molten NaCl and KCl so that it has been found that the thermal conductivity has the packing-fraction dependence of η2/3 which is much weaker than that of the simple LJ liquids.

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

    SciTech Connect

    Chakraborty, Subrata; Davis, Ryan; Ahmed, Musahid; Jackson, Teresa L.; Thiemens, Mark H.

    2012-01-03

    Several absorption bands exist in the VUV region of Carbon monoxide (CO). Emission spectra indicate that these bands are all predissociative. An experimental investigation of CO photodissociation by vacuum ultraviolet photons (90 to 108 nm; ~13 to 11 eV) from the Advanced Light Source Synchrotron and direct measurement of the associated oxygen isotopic composition of the products are presented here. A wavelength dependency of the oxygen isotopic composition in the photodissociation product was observed. Slope values (δ'{sup 18}O/ δ'{sup 17}O) ranging from 0.76 to 1.32 were observed in oxygen three-isotope space (δ'{sup 18}O vs. δ'{sup 17}O) which correlated with increasing synchrotron photon energy, and indicate a dependency of the upper electronic state specific dissociation dynamics (e.g., perturbation and coupling associated with a particular state). An unprecedented magnitude in isotope separation was observed for photodissociation at the 105 and 107 nm synchrotron bands and are found to be associated with accidental predissociation of the vibrational states ({nu} = 0 and 1) of the upper electronic state E{sup 1}Π. For each synchrotron band, a large (few hundred per mil) extent of isotopic fractionation was observed and the range of fractionation is a combination of column density and exposure time. A significant temperature dependency in oxygen isotopic fractionation was observed, indicating a rotational level dependency in the predissociation process.

  5. Deuterium in Iceland waters

    USGS Publications Warehouse

    Friedman, I.; Sigurgeirsson, T.; Gardarsson, O.

    1963-01-01

    From the deuterium analysis of 159 samples of water collected in Iceland from hot-water boreholes, cold and hot springs, rivers and rain, the geographical distribution of deuterium in surface waters is plotted. On the basis of the deuterium analysis, the water from boreholes near Reykjavik does not originate from local precipitation. The variation of deuterium content of these water wells with time suggests that these data can be used to determine the time of travel of recharge water to the various boreholes, as well as the surface recharge area. ?? 1963.

  6. Thermal conductivity of simple liquids: Origin of temperature and packing fraction dependences

    NASA Astrophysics Data System (ADS)

    Ishii, Yoshiki; Sato, Keisuke; Salanne, Mathieu; Madden, Paul A.; Ohtori, Norikazu

    2014-03-01

    The origin of both weak temperature dependence and packing fraction dependence of T1/4η3/2 in the thermal conductivity of the simple Lennard-Jones (LJ) liquid is explored. In order to discuss the relative contributions from attractive or repulsive part of the interaction potential separately, the thermal conductivity of a series of Weeks-Chandler-Anderson (WCA) fluids is calculated by molecular dynamics simulations. The results show that the repulsive part plays the main role in the heat conduction, while the attractive part has no direct effect on the thermal conductivity for a given packing fraction. By investigating WCA fluids with potentials of varying softness, we explain the difference observed between the LJ liquids such as argon and Coulombic liquids such as NaCl.

  7. Diffusion of spherical solutes: A fractional molecular-hydrodynamic study of solvent dependence

    NASA Astrophysics Data System (ADS)

    Chan, T. C.; Li, K. Y.; Li, H. T.

    2016-04-01

    Diffusivities of tetramethyltin, tetraethyltin, tetraethyllead, and 2,2-dichloropropane in methanol as well as tetraethyltin and tetraethyllead in ethanol were measured and combined with other literature data of spherical solutes in various solvents to study the effects of solvent on diffusivity. A new fractional molecular-hydrodynamic relation is found to well represent the solvent dependence for the diffusivities of carbon tetrachloride, tetramethyltin, tetraethyltin, tetrapropyltin, and tetrabutyltin at diverse temperatures. The relation consists of two components: one is a function of the hydrodynamic viscosity and the other associated with the molecular properties of solvent. Each has a fractional exponent dependent on solute size. The results here indicate that the relative importance of the viscosity component consistently increases with solute size, but that the trend for the molecular component is reversed. Comparison with other diffusion relations reveals that the newly developed model is more applicable and accurate for expressing the effects of solvent on diffusivity.

  8. Mass dependent stable isotope fractionation of mercury during mer mediated microbial degradation of monomethylmercury

    NASA Astrophysics Data System (ADS)

    Kritee, K.; Barkay, Tamar; Blum, Joel D.

    2009-03-01

    Controlling bioaccumulation of toxic monomethylmercury (MMHg) in aquatic food chains requires differentiation between biotic and abiotic pathways that lead to its production and degradation. Recent mercury (Hg) stable isotope measurements of natural samples suggest that Hg isotope ratios can be a powerful proxy for tracing dominant Hg transforming pathways in aquatic ecosystems. Specifically, it has been shown that photo-degradation of MMHg causes both mass dependent (MDF) and mass independent fractionation (MIF) of Hg isotopes. Because the extent of MDF and MIF observed in natural samples (e.g., fish, soil and sediments) can potentially be used to determine the relative importance of pathways leading to MMHg accumulation, it is important to determine the potential role of microbial pathways in contributing to the fractionation, especially MIF, observed in these samples. This study reports the extent of fractionation of Hg stable isotopes during degradation of MMHg to volatile elemental Hg and methane via the microbial Hg resistance ( mer) pathway in Escherichia coli carrying a mercury resistance ( mer) genetic system on a multi-copy plasmid. During experimental microbial degradation of MMHg, MMHg remaining in reactors became progressively heavier (increasing δ202Hg) with time and underwent mass dependent Rayleigh fractionation with a fractionation factor α202/198 = 1.0004 ± 0.0002 (2SD). However, MIF was not observed in any of the microbial MMHg degradation experiments indicating that the isotopic signature left by mer mediated MMHg degradation is significantly different from fractionation observed during DOC mediated photo-degradation of MMHg. Additionally, a clear suppression of Hg isotope fractionation, both during reduction of Hg(II) and degradation of MMHg, was observed when the cell densities increased, possibly due to a reduction in substrate bioavailability. We propose a multi-step framework for understanding the extent of fractionation seen in our MMHg

  9. Size-dependent geometrically nonlinear free vibration analysis of fractional viscoelastic nanobeams based on the nonlocal elasticity theory

    NASA Astrophysics Data System (ADS)

    Ansari, R.; Faraji Oskouie, M.; Gholami, R.

    2016-01-01

    In recent decades, mathematical modeling and engineering applications of fractional-order calculus have been extensively utilized to provide efficient simulation tools in the field of solid mechanics. In this paper, a nonlinear fractional nonlocal Euler-Bernoulli beam model is established using the concept of fractional derivative and nonlocal elasticity theory to investigate the size-dependent geometrically nonlinear free vibration of fractional viscoelastic nanobeams. The non-classical fractional integro-differential Euler-Bernoulli beam model contains the nonlocal parameter, viscoelasticity coefficient and order of the fractional derivative to interpret the size effect, viscoelastic material and fractional behavior in the nanoscale fractional viscoelastic structures, respectively. In the solution procedure, the Galerkin method is employed to reduce the fractional integro-partial differential governing equation to a fractional ordinary differential equation in the time domain. Afterwards, the predictor-corrector method is used to solve the nonlinear fractional time-dependent equation. Finally, the influences of nonlocal parameter, order of fractional derivative and viscoelasticity coefficient on the nonlinear time response of fractional viscoelastic nanobeams are discussed in detail. Moreover, comparisons are made between the time responses of linear and nonlinear models.

  10. THE ENVIRONMENTAL DEPENDENCE OF THE FRACTION OF 'UNCONVENTIONAL' GALAXIES: RED LATE TYPES AND BLUE EARLY TYPES

    SciTech Connect

    Deng Xinfa; He Jizhou; Wu Ping; Ding Yingping

    2009-07-10

    From the Main galaxy sample of the Sloan Digital Sky Survey Data Release 6, we construct two volume-limited samples with the luminosity -20.0 {<=} M{sub r} {<=} -18.5 and -22.40 {<=} M{sub r} {<=} -20.16, respectively, to explore the environmental dependence of the fraction of 'unconventional' galaxies: red late types and blue early types. We use the density estimator within the distance to the fifth nearest neighbor, and construct two samples at both extremes of density and perform comparative studies between them for each volume-limited sample. Results of two volume-limited samples show the same conclusions: the fraction of red late-type galaxies rises considerably with increasing local density, and that one of the blue early-type galaxies declines substantially with increasing local density. In addition, we note that bluer galaxies preferentially are late types, but the red galaxies are not dominated by early types.

  11. Reporting and measurement of mass-dependent and mass-independent fractionation of mercury isotopes

    NASA Astrophysics Data System (ADS)

    Bergquist, B. A.; Blum, J. D.

    2007-12-01

    Hg isotope analysis by MC-ICP-MS is an important new approach for fingerprinting Hg sources and monitoring Hg redox reactions and bioaccumulation, especially with the recent discovery of mass independent Hg isotope fractionation. Unfortunately research groups have adopted different standards, definitions of delta values, and methods of isotopic measurement. We suggest that a single standard, NIST SRM 3133, be adopted for reporting the isotopic variability of Hg isotopes. Isotope ratios should be determined by sample-standard bracketing (SSB) during analysis and reported as permil (‰) deviation from SRM 3133. For the highest precision and accuracy, a Tl internal standard along with SSB should be used to correct instrumental mass bias. Measurement routines should also include on-peak zero corrections and matching of concentration and matrix between the samples and bracketing standard. For samples that display mass-dependent fractionation (MDF), only one delta value needs to be reported (δ202/198Hg). Mass-independent fractionation (MIF) (Jackson et al., 2006; Bergquist et al., 2006; Bergquist and Blum, submitted) requires additional nomenclature, and we suggest reporting MIF as the deviation in isotope ratios from the theoretical mass dependent kinetic isotope fractionation (Δxxx/198Hg)¬. External reproducibility should be monitored by analysis of secondary standards. For studies of MDF, we use an in-house secondary standard solution made from metallic Hg mined from Almaden Spain and obtain a δ202Hg of -0.55 ±0.06‰ (2SD). For studies of MIF, we use NRCC CRM DORM-2 (dogfish muscle) and obtain a mean value of δ202Hg of +0.19 ±0.13‰ (2SD), Δ201Hg of +0.89 ±0.07‰ (2SD) , and Δ199Hg of +1.07 ±0.08‰ (2SD).

  12. Deuterium permeation through copper with trapping impurities

    NASA Astrophysics Data System (ADS)

    Mitchell, D. J.; Harris, J. M.; Patrick, R. C.; Boespflug, E. P.; Beavis, L. C.

    1982-02-01

    The time dependence of the deuterium permeation rate through impurity-doped copper membranes was measured in the temperature range 300-700 °C. Copper membranes that were doped with Er, Zr, and Ti all exhibited permeabilities that were nearly equal to pure copper, but the apparent diffusivities were smaller than those for pure copper by factors of 10-100 over the experimental temperature range. The permeation characteristics of these alloys appear to be altered from those for pure copper due to trapping of deuterium at sites that are associated with the impurity atoms. It is shown that the deuterium permeation rate through the copper alloys can be expressed in an analytical form that is analogous to that for pure copper, except that the apparent diffusivity takes on a value which depends on the trap concentration and binding energy for deuterium. The binding energies that are calculated for the alloys are used to determine the lag time which is required for deuterium or hydrogen to permeate through initially evacuated membranes. The lag times for copper alloys containing about 1% Er, Zr, or Ti are many orders of magnitude longer than for pure copper at room temperature. Copper alloys containing Cr do not appear to exhibit deuterium trapping. Nuclear reaction and backscattering analyses were used to help determine the effect or surface oxides on the permeation measurements.

  13. ORIGINS OF NON-MASS-DEPENDENT FRACTIONATION OF EXTRA-TERRESTRIAL OXYGEN

    SciTech Connect

    Barcena, Homar; Connolly, Harold C.

    2012-08-01

    The distribution of oxygen isotopes in meteorites and within the earliest solids that formed in the solar system hints that the precursors of these materials must have undergone a mass-independent process. The mass-independent process is specifically one that fractionates {sup 16}O from {sup 17}O and {sup 18}O. This chemical signature is indicative of non-equilibrium processing, which bear resemblance to some unusual terrestrial phenomenon such as fractionation of ozone in the upper Earth atmosphere. That the mass-independent fractionation of oxygen isotopes is preserved within petrological records presents planetary scientists interesting clues to the events that may have occurred during the formation of the solar system. Currently, there are several hypotheses on the origins of the oxygen isotope distribution within primitive planetary materials, which include both thermal and photochemical models. We present a new model based on a physico-chemical hypothesis for the origin of non-mass-dependent O-isotope distribution in oxygen-bearing extra-terrestrial materials, which originated from the disproportionation of CO in dark molecular clouds to create CO{sub 2} reservoirs. The disproportionation created a reservoir of heavy oxygen isotopes and could have occurred throughout the evolution of the disk. The CO{sub 2} was a carrier of the isotope anomaly in the solar nebula and we propose that non-steady-state mixing of these reservoirs with the early rock-forming materials during their formation corresponds with the birth and evolution of the solar system.

  14. Bulk retention of deuterium in graphites exposed to deuterium plasma at high temperature

    NASA Astrophysics Data System (ADS)

    Arkhipov, I. I.; Gorodetsky, A. E.; Zakharov, A. P.; Khripunov, B. I.; Shapkin, V. V.; Petrov, V. B.; Pistunovich, V. I.; Negodaev, M. A.; Bagulya, A. V.

    1996-10-01

    A highly ionized deuterium plasma with a low residual gas pressure and a high intensity D 2+-ion beam were used for the study of deuterium retention in RG-Ti-91 and POCO AXF-5Q graphites. Deuterium retention in the samples was estimated by TDS during heating to 2000 K. Mechanical removal of a surface layer 100 μm thick was used to distinguish bulk and surface fractions of retained deuterium. The samples of RG-Ti and POCO graphites were exposed to a plasma with an ion flux of 3 × 10 17 D/cm 2 · s in the 'Lenta' plasma device for 10 to 10 4 s at residual deuterium pressure of 0.04 Pa at 1400 K. Under plasma exposure deuterium capture in RG-Ti graphite reached the saturation level at a fluence of 4 × 10 20 D/cm 2 while the bulk inventory was negligible. As for POCO graphite, deuterium retention increased with fluence and was equal to 18 appm in the bulk for a fluence of 7 × 10 21 D/cm 2. The same amount of deuterium in the bulk was obtained after gas exposure of POCO at an effective pressure of 0.8 Pa (1400 K, 6 h). With this result, the tritium concentration in the plasma-facing graphite materials can reach 1500 appm or 380 grams of tritium per ton of graphite. To understand the role of ion flux in generation of effective pressure, POCO was irradiated with 16 keV D 2+-ions at 1400 K for 4 h to 8 × 10 20 D/cm 2 (ion flux was 6 × 10 16 D/cm 2 · s, residual deuterium pressure was 0.004 Pa). The results are discussed on the basis of structural differences for POCO and RG-Ti graphites.

  15. Inelastic dark matter with spin-dependent couplings to protons and large modulation fractions in DAMA

    NASA Astrophysics Data System (ADS)

    Scopel, Stefano; Yoon, Kook-Hyun

    2016-02-01

    We discuss a scenario where the DAMA modulation effect is explained by a Weakly Interacting Massive Particle (WIMP) which upscatters inelastically to a heavier state and predominantly couples to the spin of protons. In this scenario constraints from xenon and germanium targets are evaded dynamically, due to the suppression of the WIMP coupling to neutrons, while those from fluorine targets are evaded kinematically, because the minimal WIMP incoming speed required to trigger upscatters off fluorine exceeds the maximal WIMP velocity in the Galaxy, or is very close to it. In this scenario WIMP scatterings off sodium are usually sensitive to the large-speed tail of the WIMP velocity distribution and modulated fractions of the signal close to unity arise in a natural way. On the other hand, a halo-independent analysis with more conservative assumptions about the WIMP velocity distribution allows to extend the viable parameter space to configurations where large modulated fractions are not strictly necessary. We discuss large modulated fractions in the Maxwellian case showing that they imply a departure from the usual cosine time dependence of the expected signal in DAMA. However we explicitly show that the DAMA data is not sensitive to this distortion, both in time and frequency space, even in the extreme case of a 100 % modulated fraction. Moreover the same scenario provides an explanation of the maximum in the energy spectrum of the modulation amplitude detected by DAMA in terms of WIMPs whose minimal incoming speed matches the kinematic threshold for inelastic upscatters. For the elastic case the detection of such maximum suggests an inversion of the modulation phase below the present DAMA energy threshold, while this is not expected for inelastic scattering. This may allow to discriminate between the two scenarios in a future low-threshold analysis of the DAMA data.

  16. An inverse time-dependent source problem for a time-fractional diffusion equation

    NASA Astrophysics Data System (ADS)

    Wei, T.; Li, X. L.; Li, Y. S.

    2016-08-01

    This paper is devoted to identifying a time-dependent source term in a multi-dimensional time-fractional diffusion equation from boundary Cauchy data. The existence and uniqueness of a strong solution for the corresponding direct problem with homogeneous Neumann boundary condition are firstly proved. We provide the uniqueness and a stability estimate for the inverse time-dependent source problem. Then we use the Tikhonov regularization method to solve the inverse source problem and propose a conjugate gradient algorithm to find a good approximation to the minimizer of the Tikhonov regularization functional. Numerical examples in one-dimensional and two-dimensional cases are provided to show the effectiveness of the proposed method. This paper was supported by the NSF of China (11371181) and the Fundamental Research Funds for the Central Universities (lzujbky-2013-k02).

  17. Deuterium in the daytime thermosphere

    NASA Technical Reports Server (NTRS)

    Breig, E. L.; Sanatani, S.; Hanson, W. B.

    1987-01-01

    Ion concentration measurements for H(+) and D(+) from the magnetic ion mass spectrometer on the Atmosphere Explorer C satellite are used, in conjunction with other atmospheric data, to determine the concentrations of H and D in the nonpolar daytime thermosphere. The ratio of the observed D(+) to H(+) concentrations has essentially the same height dependence in the 300 to 800-km region as expected for their neutral counterparts, even in the presence of ion temperature gradients and probable large vertical ion fluxes. Rapid charge exchange with atomic oxygen ensures that D/H is about equal to D(+)/H(+) at the lower altitudes where the derived D to H concentration ratio is a factor of about 6 larger than its sea level value, for an exospheric temperature of 930 K. This relative enhancement of deuterium arises from the fact that hydrogen more readily escapes the earth, and a large vertical gradient in the H concentration relative to its diffusive equilibrium value is necessary to drive this upward flux through the lower thermosphere. If these planetary losses of hydrogen are much greater than those associated with evaporative escape, as is the current view, then correspondingly larger deuterium loss rates are also likely in order that the thermospheric D/H ratio not increase well above the observed value. The absolute winter daytime concentration of deuterium at 300 km is found to be 210 + or - 50 atoms/cu cm.

  18. Deuterium surface segregation in titanium alloys

    NASA Astrophysics Data System (ADS)

    Adler, Philip N.; Schulte, Robert L.; Margolin, Harold

    1990-07-01

    Deuterium surface segregation has been investigated in α, α + β, and β-phase titanium that were deuterium charged over the range of 2 to approximately 300 wppm. Surface segregation was observed in samples that were essentially α-phase materials, i.e., high-purity commercial α-Ti, Ti-6A1, and Ti-3A1-2.5V, whereas Ti-6A1-4V had slight enrichment and β-Ti-13Mn had no detectable segregation. Nuclear reaction analysis (NRA) techniques were used to measure the near-surface deuterium concentration, and the segregation has been localized to within 50 nm of the surface. The time-dependent increase of deuterium at the surface is consistent with deuterium diffusion from the bulk to the surface and a room-temperature diffusivity of approximately 3 × 10-9 cm2/s. Surface enrichment in excess of 30 times the bulk concentration was observed in charged samples and in excess of 60 times for samples that had been charged and then vacuum annealed. Polishing was found to be of importance in causing segregation. The presence of deuterides or a surface defect state is suggested to explain the deuterium surface enrichment.

  19. Interstellar Deuterium Chemistry

    NASA Technical Reports Server (NTRS)

    Sandford, S. A.

    2003-01-01

    The presence of isotopic anomalies is the most unequivocal demonstration that meteoritic material contains circumstellar or interstellar components. In the case of organic compounds in meteorites and interplanetary dust particles (IDPs), the most useful isotopic tracer of interstellar components has been deuterium (D) excesses. In some cases these enrichments are seen in bulk meteoritic materials, but D enrichments have also been observed in meteoritic subfractions and even within specific classes of molecular species, such as amino and carboxylic acids. These anomalies are not thought to be the result of nucleosynthetic processes, but are instead ascribed to chemical and physical processes occurring in the interstellar medium (ISM). The traditional explanation of these D excesses has been to invoke the presence of materials made in the ISM by low temperature gas phase ion-molecule reactions. Indeed, the DM ratios seen in the simple interstellar gas phase molecules in cold dense clouds amenable to measurement using radio spectral techniques are generally considerably higher than the values seen in enriched Solar System materials. However, the true linkage between the DM ratios in interstellar and meteoritic materials is obscured by several effects. First, current observations of D enrichment in the ISM have been made of only a few simple molecules, molecules that are not the main carriers of D in Solar System materials. Second, some of the interstellar D enrichment is likely to reside on labile moieties that will have exchanged to some degree with more isotopically normal material during incorporation into the warm protosolar nebula, parent body processing, delivery, recovery, and analysis. Third, ion-molecule reactions represent only one of at least four processes that can produce strong D-H fractionation in the ISM.

  20. Photochemical self-shielding as a source of non-mass-dependent isotope fractionation

    NASA Astrophysics Data System (ADS)

    Lyons, James; Stark, Glenn; Blackie, Doug; Pickering, Juliet; Heays, Alan

    2010-05-01

    Very large isotopic enrichments occur in the photolysis products of molecules that have line-type absorption spectra. Abundance-dependent line saturation, a process termed photochemical self-shielding, yields large non-mass-dependent (NMD) isotope effects, and has been proposed to have occurred in CO in the solar nebula (Clayton 2002) and SO2 in the early Earth atmosphere (Lyons 2007). The NMD signatures derived from photolysis of CO and SO2 are believed to be recorded in primitive meteorites inclusions (CAIs) and in Archean/Paleoproterozoic sulfur sediments, respectively. Comparison of theory and experiment can be used to distinguish self-shielding from other NMD processes. Recent low-resolution (~10 cm^-1) measurements of isotopic SO2 cross sections (Danielache et al. 2008) exhibit NMD effects when included in photoechemical models (Ueno et al. 2009), but not as a result of self-shielding. Higher resolution measurements (1-0.2 cm^-1) of isotopic cross sections are in progress at Imperial College. Inclusion of preliminary 1 cm^-1 resolution cross sections in a photochemical model for Earth's early atmosphere clearly demonstrates that isotopic self-shielding is present, yielding d33S>0 and d34S>0 in photoproduct SO. However, uncertainties in the measured cross sections also introduce NMD signatures. We are presently working to remove these uncertainties. Recent experiments on CO photodissociation at wavelengths ~91-108 nm show very large NMD effects in oxygen (Chakraborty et al. 2008). Because the measured NMD signatures are wavelength dependent, and differ in delta-values (i.e., d17O/d18O not equal unity), Chakraborty et al. claim that their experiments rule out CO self-shielding as the mechanism for the meteorite CAI slope-1 line. Here we show via model simulation of the experiments that the non-unity d17O/d18O values result primarily from self-shielding effects in both C16O and C18O. Also, model results indicate that the non-unity d17O/d18O values only arise for

  1. EVIDENCE FOR MULTIPLE PATHWAYS TO DEUTERIUM ENHANCEMENTS IN PROTOPLANETARY DISKS

    SciTech Connect

    Oeberg, Karin I.; Qi, Chunhua; Wilner, David J.; Hogerheijde, Michiel R.

    2012-04-20

    The distributions of deuterated molecules in protoplanetary disks are expected to depend on the molecular formation pathways. We use observations of spatially resolved DCN emission from the disk around TW Hya, acquired during ALMA science verification with a {approx}3'' synthesized beam, together with comparable DCO{sup +} observations from the Submillimeter Array, to investigate differences in the radial distributions of these species and hence differences in their formation chemistry. In contrast to DCO{sup +}, which shows an increasing column density with radius, DCN is better fit by a model that is centrally peaked. We infer that DCN forms at a smaller radii and thus at higher temperatures than DCO{sup +}. This is consistent with chemical network model predictions of DCO{sup +} formation from H{sub 2}D{sup +} at T < 30 K and DCN formation from additional pathways involving CH{sub 2}D{sup +} at higher temperatures. We estimate a DCN/HCN abundance ratio of {approx}0.017, similar to the DCO{sup +}/HCO{sup +} abundance ratio. Deuterium fractionation appears to be efficient at a range of temperatures in this protoplanetary disk. These results suggest caution in interpreting the range of deuterium fractions observed in solar system bodies, as multiple formation pathways should be taken into account.

  2. Fractional photo-current dependence of graphene quantum dots prepared from carbon nanotubes.

    PubMed

    Kundu, Sumana; Ghosh, Sujoy; Fralaide, Michael; Narayanan, T N; Pillai, Vijayamohanan K; Talapatra, Saikat

    2015-10-14

    We report on the photo-conductivity studies of chemically synthesized graphene quantum dots (GQDs) of average size 12 nm obtained by the oxidative acid treatment of MWCNTs. The dependence of photocurrent Iph (Iph = Iill - Idark) on the laser intensity P under a wide range of laser intensities (5 mW ≤ P ≤ 60 mW) shows a fractional power dependence of Iph on light intensity. The temperature dependence (300 K < T < 50 K) of Iph observed in thin films of these GQDs indicates that in the higher temperature region (T > ∼100 K), as the temperature increases, the number of thermally generated carriers increase resulting in increased Iph. At sufficiently low temperatures (T ≤ 100 K), a constant Iph is observed, indicating a constant photo-carrier density. Such a behavior is typically observed in many photoactive disordered semiconductors, which are often used in a variety of applications. We believe that the investigations presented here will enhance our understanding of the photocurrent generation phenomenon in chemically obtained GQDs. PMID:26351706

  3. Mass-Dependent and -Independent Fractionation of Mercury Isotopes in Aquatic Systems

    NASA Astrophysics Data System (ADS)

    Bergquist, B. A.; Joel, B. D.; Jude, D. J.

    2008-12-01

    Mercury is a globally distributed and highly toxic pollutant. Although Hg is a proven health risk, much of the natural cycle of Hg is not well understood and new approaches are needed to track Hg and the chemical transformations it undergoes in the environment. Recently, we demonstrated that Hg isotopes exhibit two types of isotope fractionation: (1) mass dependent fractionation (MDF) and (2) mass independent fractionation (MIF) of only the odd isotopes (Bergquist and Blum, 2007). The observation of large MIF of Hg isotopes (up to 5 permil) is exciting because only a few other isotopic systems have been documented to display large MIF, the most notable of which are oxygen and sulfur. In both cases, the application of MIF has proven very useful in a variety of fields including cosmochemistry, paleoclimatology, physical chemistry, atmospheric chemistry, and biogeochemistry. Both MDF and MIF isotopic signatures are observed in natural samples, and together they open the door to a new method for tracing Hg pollution and for investigating Hg behavior in the environment. For example, fish record MDF that appears to be related to size and age. Additionally, fish display MIF signatures that are consistent with the photo-reduction of methylmercury (Bergquist and Blum, 2007). If the MDF and MIF in ecosystems can be understood, the signatures in fish could inform us about the sources and processes transforming Hg and why there are differences in the bioaccumulation of Hg in differing ecosystems and populations of fish. This requires sampling of a variety of ecosystems, the sampling of many components of the ecosystems, and the use of other tracers such as carbon and nitrogen isotopes. We have expanded our studies of aquatic ecosystems to include several lakes in North America. Similar to other isotopic systems used to study food web dynamics and structure (i.e., C and N), the MDF of Hg in fish appears to be related to size and age. The MDF recorded in fish likely reflects

  4. The Deuterium Chemistry of the Early Universe

    SciTech Connect

    Stancil, P.C.; Lepp, S.; Dalgarno, A.

    1998-12-01

    The chemistry of deuterium, as well as that of hydrogen and helium, in the postrecombination era of the expanding early universe is presented. A thorough survey of all potentially important gas-phase reactions involving the primordial elements produced in the Big Bang, with a particular emphasis on deuterium, is given. The reaction set, consisting of 144 processes, is used in a nonequilibrium chemistry model to follow the production of primordial molecules in the postrecombination era. It is found that significant deuterium fractionation occurs for HD{sup +}, HD, and H{sub 2}D{sup +}, while the abundance of D{sup +} is reduced compared to the proton abundance. Even with the enhanced fractionation of H{sub 2}D{sup +}, its abundance is predicted to be too small to cause any interesting cosmological consequences, such as possible attenuation of spatial anisotropies in the cosmic background radiation field, detections of the epochs of reionization and reheating, or constraints on the primordial deuterium abundance. HD, being the second most abundant primordial molecule after H{sub 2}, may play a role in subsequent structure formation because of its cooling radiation. {copyright} {ital {copyright} 1998.} {ital The American Astronomical Society}

  5. Blister formation and deuterium retention on tungsten exposed to low energy and high flux deuterium plasma

    NASA Astrophysics Data System (ADS)

    Tokunaga, K.; Baldwin, M. J.; Doerner, R. P.; Noda, N.; Kubota, Y.; Yoshida, N.; Sogabe, T.; Kato, T.; Schedler, B.

    2005-03-01

    Deuterium ion irradiation on tungsten has been carried out with incident energies of 100 eV and flux of 1 × 10 22 D + m -2 s -1 at a temperature in range between 333 K and 1130 K up to a dose of 1 × 10 26 D + m -2. Three kinds of tungsten used are pure tungsten made by powder metallurgy tungsten (PM-W), vacuum plasma spray tungsten (VPS-W) and single crystal tungsten (SC-W). Surface morphology before and after the irradiation is observed with an SEM. In addition, retention property of deuterium after the irradiation is also examined with a TDS. Behavior of blister formation depends on the kind of the samples and the irradiation temperatures. TDS measurement also shows that deuterium is not retained in sample, which the blisters are not formed. The behavior of the blister formation and deuterium retention is influenced by the manufacturing process and the sample history of tungsten.

  6. Tritium catalyzed deuterium tokamaks

    SciTech Connect

    Greenspan, E.; Miley, G.H.; Jung, J.; Gilligan, J.

    1984-04-01

    A preliminary assessment of the promise of the Tritium Catalyzed Deuterium (TCD) tokamak power reactors relative to that of deuterium-tritium (D-T) and catalyzed deuterium (Cat-D) tokamaks is undertaken. The TCD mode of operation is arrived at by converting the /sup 3/He from the D(D,n)/sup 3/He reaction into tritium, by neutron capture in the blanket; the tritium thus produced is fed into the plasma. There are three main parts to the assessment: blanket study, reactor design and economic analysis and an assessment of the prospects for improvements in the performance of TCD reactors (and in the promise of the TCD mode of operation, in general).

  7. Distinction of tris(diimine)ruthenium(II) enantiomers chiral by virtue of helical chirality: temperature-dependent deuterium NMR spectroscopy in partially oriented phases.

    PubMed

    Szalontai, Gábor; Kovács, Margit

    2006-11-01

    2H NMR spectra of perdeuterated tris(diimine)ruthenium(II) complexes have been recorded in lyotropic liquid crystalline phase formed by the chiral polypeptide, poly-gamma-benzyl-L-glutamate (PBLG) and co-solvents. It is demonstrated that the left- and right-rotation isomers of these octahedral metal complexes with D3 symmetry can be distinguished. The effects of temperature and ligand size on spectral resolution were also studied. Although in the case of free bipyridine ligands excellent optical resolution could be obtained at room temperature in the complexes studied, the increase in ligand size has a detrimental effect on the resolution. This can be compensated to some extent by elevating the sample temperature and decreasing the deuterium relaxation rates, but the available temperature range and therefore the applicability of the technique are limited. PMID:16958156

  8. Diffusion in heterogeneous media: An iterative scheme for finding approximate solutions to fractional differential equations with time-dependent coefficients

    NASA Astrophysics Data System (ADS)

    Bologna, Mauro; Svenkeson, Adam; West, Bruce J.; Grigolini, Paolo

    2015-07-01

    Diffusion processes in heterogeneous media, and biological systems in particular, are riddled with the difficult theoretical issue of whether the true origin of anomalous behavior is renewal or memory, or a special combination of the two. Accounting for the possible mixture of renewal and memory sources of subdiffusion is challenging from a computational point of view as well. This problem is exacerbated by the limited number of techniques available for solving fractional diffusion equations with time-dependent coefficients. We propose an iterative scheme for solving fractional differential equations with time-dependent coefficients that is based on a parametric expansion in the fractional index. We demonstrate how this method can be used to predict the long-time behavior of nonautonomous fractional differential equations by studying the anomalous diffusion process arising from a mixture of renewal and memory sources.

  9. Analytical solutions to the fractional advection-diffusion equation with time-dependent pulses on the boundary

    NASA Astrophysics Data System (ADS)

    Rubbab, Qammar; Mirza, Itrat Abbas; Qureshi, M. Zubair Akbar

    2016-07-01

    The time-fractional advection-diffusion equation with Caputo-Fabrizio fractional derivatives (fractional derivatives without singular kernel) is considered under the time-dependent emissions on the boundary and the first order chemical reaction. The non-dimensional problem is formulated by using suitable dimensionless variables and the fundamental solutions to the Dirichlet problem for the fractional advection-diffusion equation are determined using the integral transforms technique. The fundamental solutions for the ordinary advection-diffusion equation, fractional and ordinary diffusion equation are obtained as limiting cases of the previous model. Using Duhamel's principle, the analytical solutions to the Dirichlet problem with time-dependent boundary pulses have been obtained. The influence of the fractional parameter and of the drift parameter on the solute concentration in various spatial positions was analyzed by numerical calculations. It is found that the variation of the fractional parameter has a significant effect on the solute concentration, namely, the memory effects lead to the retardation of the mass transport.

  10. An update on the Thermal Gradient Induced Non -Mass-Dependent Isotope Fractionation

    NASA Astrophysics Data System (ADS)

    Sun, T.; Niles, P. B.; Bao, H.; Socki, R. A.

    2012-12-01

    Mass flow and compositional gradient (elemental and isotope separation) occur when fluid(s) or gas(es) in an enclosure is subjected to a thermal gradient, and the phenomenon is named thermal diffusion. Gas phase thermal diffusion has been experimentally and theoretically investigated for more than a century, although there has not been a satisfactory theory to date. Nevertheless, theories predict that when dealing with a multi-isotope system, such as O16-O17-O18, S32-S33-S34-S36, or Ne20-Ne21-Ne22, the mass difference is the only term in the thermal diffusion separation factors that distinguish one isotope pair from another. Thus a mass dependent relationship is expected. For O-bearing molecules the α17O/ α 18O is expected to be at 0.5 to 0.515, and for S-bearing molecules the α33S/ α 34S at 0.5 to 0.508, where α is isotope fractionation factor between cold and warm reservoirs. We recently reported that thermal diffusion generates non-mass dependent (NMD) isotope fractionation for low-pressure O2 and SF6 gases. The observed NMD phenomenon in the simple thermal-diffusion experiments demands quantitative validation and theoretical explanation. It was suggested that additional (not mass related) terms need to be theoretically considered in the order to account for the observations. In addition to the pressure and temperature dependency illustrated in our earlier report, the role of turbulence, batch gas effects, and whether it is only a transient, non-equilibrium effect have been examined in this study. We report here new results on low-pressure O2 gas thermal diffusion. (1) In a purely diffusive vertical two-bulb setting with colder reservoir at lower position, time course experiments showed that the NMD effect persists after the system reaches isotopic steady state between warmer and colder compartments, suggesting that the effect is not a transient one. (2) When the average temperature approaching condensation point for O2, the 17O switches to migrating

  11. Nucleation and growth of micellar polycrystals under time-dependent volume fraction conditions

    NASA Astrophysics Data System (ADS)

    Louhichi, Ameur; Tamborini, Elisa; Ghofraniha, Neda; Caton, François; Roux, Denis; Oberdisse, Julian; Cipelletti, Luca; Ramos, Laurence

    2013-03-01

    We study the freezing kinetics of colloidal polycrystals made of micelles of Pluronic F108, a thermosensitive copolymer, to which a small amount of silica nanoparticles of a size comparable to that of the micelles are added. We use rheology and calorimetry to measure Tc, the crystallization temperature, and find that Tc increases with the heating rate Ṫ used to crystallize the sample. To rationalize our results, we first use viscosity measurements to establish a linear mapping between temperature T and the effective volume fraction, φ, of the micelles, treated as hard spheres. Next, we reproduce the experimental Ṫ dependence of the crystallization temperature with numerical calculations based on standard models for the nucleation and growth of hard-sphere crystals, classical nucleation theory and the Johnson-Mehl-Avrami-Kolmogorov theory. The models have been adapted to account for the peculiarities of our experiments: the presence of nanoparticles that are expelled in the grain boundaries and the steady increase of T and, hence, φ during the experiment. We moreover show that the polycrystal grain size obtained from the calculations is in good agreement with light microscopy data. Finally, we find that the φ dependence of the nucleation rate for the micellar polycrystal is in remarkable quantitative agreement with that found in previous experiments on colloidal hard spheres. These results suggests that deep analogies exist between hard-sphere colloidal crystals and Pluronics micellar crystals, in spite of the difference in particle softness. More generally, our results demonstrate that crystallization processes can be quantitatively probed using standard rheometry.

  12. Time-dependence of sea-ice concentration and multiyear ice fraction in the Arctic Basin

    USGS Publications Warehouse

    Gloersen, P.; Zwally, H.J.; Chang, A.T.C.; Hall, D.K.; Campbell, W.J.; Ramseier, R.O.

    1978-01-01

    The time variation of the sea-ice concentration and multiyear ice fraction within the pack ice in the Arctic Basin is examined, using microwave images of sea ice recently acquired by the Nimbus-5 spacecraft and the NASA CV-990 airborne laboratory. The images used for these studies were constructed from data acquired from the Electrically Scanned Microwave Radiometer (ESMR) which records radiation from earth and its atmosphere at a wavelength of 1.55 cm. Data are analyzed for four seasons during 1973-1975 to illustrate some basic differences in the properties of the sea ice during those times. Spacecraft data are compared with corresponding NASA CV-990 airborne laboratory data obtained over wide areas in the Arctic Basin during the Main Arctic Ice Dynamics Joint Experiment (1975) to illustrate the applicability of passive-microwave remote sensing for monitoring the time dependence of sea-ice concentration (divergence). These observations indicate significant variations in the sea-ice concentration in the spring, late fall and early winter. In addition, deep in the interior of the Arctic polar sea-ice pack, heretofore unobserved large areas, several hundred kilometers in extent, of sea-ice concentrations as low as 50% are indicated. ?? 1978 D. Reidel Publishing Company.

  13. Integration by parts and Pohozaev identities for space-dependent fractional-order operators

    NASA Astrophysics Data System (ADS)

    Grubb, Gerd

    2016-08-01

    Consider a classical elliptic pseudodifferential operator P on Rn of order 2a (0 < a < 1) with even symbol. For example, P = A(x , D)a where A (x , D) is a second-order strongly elliptic differential operator; the fractional Laplacian (- Δ)a is a particular case. For solutions u of the Dirichlet problem on a bounded smooth subset Ω ⊂Rn, we show an integration-by-parts formula with a boundary integral involving (d-a u)|∂Ω, where d (x) = dist (x , ∂ Ω). This extends recent results of Ros-Oton, Serra and Valdinoci, to operators that are x-dependent, nonsymmetric, and have lower-order parts. We also generalize their formula of Pohozaev-type, that can be used to prove unique continuation properties, and nonexistence of nontrivial solutions of semilinear problems. An illustration is given with P =(- Δ +m2)a. The basic step in our analysis is a factorization of P, P ∼P-P+, where we set up a calculus for the generalized pseudodifferential operators P± that come out of the construction.

  14. Development of a time-dependent incompressible Navier-Stokes solver based on a fractional-step method

    NASA Technical Reports Server (NTRS)

    Rosenfeld, Moshe

    1990-01-01

    The development, validation and application of a fractional step solution method of the time-dependent incompressible Navier-Stokes equations in generalized coordinate systems are discussed. A solution method that combines a finite-volume discretization with a novel choice of the dependent variables and a fractional step splitting to obtain accurate solutions in arbitrary geometries was previously developed for fixed-grids. In the present research effort, this solution method is extended to include more general situations, including cases with moving grids. The numerical techniques are enhanced to gain efficiency and generality.

  15. Load-dependent destabilization of the γ-rotor shaft in FOF1 ATP synthase revealed by hydrogen/deuterium-exchange mass spectrometry

    PubMed Central

    Vahidi, Siavash; Bi, Yumin; Dunn, Stanley D.; Konermann, Lars

    2016-01-01

    FoF1 is a membrane-bound molecular motor that uses proton-motive force (PMF) to drive the synthesis of ATP from ADP and Pi. Reverse operation generates PMF via ATP hydrolysis. Catalysis in either direction involves rotation of the γε shaft that connects the α3β3 head and the membrane-anchored cn ring. X-ray crystallography and other techniques have provided insights into the structure and function of FoF1 subcomplexes. However, interrogating the conformational dynamics of intact membrane-bound FoF1 during rotational catalysis has proven to be difficult. Here, we use hydrogen/deuterium exchange mass spectrometry to probe the inner workings of FoF1 in its natural membrane-bound state. A pronounced destabilization of the γ C-terminal helix during hydrolysis-driven rotation was observed. This behavior is attributed to torsional stress in γ, arising from γ⋅⋅⋅α3β3 interactions that cause resistance during γ rotation within the apical bearing. Intriguingly, we find that destabilization of γ occurs only when FoF1 operates against a PMF-induced torque; the effect disappears when PMF is eliminated by an uncoupler. This behavior resembles the properties of automotive engines, where bearings inflict greater forces on the crankshaft when operated under load than during idling. PMID:26884184

  16. Load-dependent destabilization of the γ-rotor shaft in FOF1 ATP synthase revealed by hydrogen/deuterium-exchange mass spectrometry.

    PubMed

    Vahidi, Siavash; Bi, Yumin; Dunn, Stanley D; Konermann, Lars

    2016-03-01

    FoF1 is a membrane-bound molecular motor that uses proton-motive force (PMF) to drive the synthesis of ATP from ADP and Pi. Reverse operation generates PMF via ATP hydrolysis. Catalysis in either direction involves rotation of the γε shaft that connects the α3β3 head and the membrane-anchored cn ring. X-ray crystallography and other techniques have provided insights into the structure and function of FoF1 subcomplexes. However, interrogating the conformational dynamics of intact membrane-bound FoF1 during rotational catalysis has proven to be difficult. Here, we use hydrogen/deuterium exchange mass spectrometry to probe the inner workings of FoF1 in its natural membrane-bound state. A pronounced destabilization of the γ C-terminal helix during hydrolysis-driven rotation was observed. This behavior is attributed to torsional stress in γ, arising from γ⋅⋅⋅α3β3 interactions that cause resistance during γ rotation within the apical bearing. Intriguingly, we find that destabilization of γ occurs only when FoF1 operates against a PMF-induced torque; the effect disappears when PMF is eliminated by an uncoupler. This behavior resembles the properties of automotive engines, where bearings inflict greater forces on the crankshaft when operated under load than during idling. PMID:26884184

  17. Deuterium trapping in tungsten

    NASA Astrophysics Data System (ADS)

    Poon, Michael

    Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation. Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation. The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D2 molecules inside the void with a trap energy of 1.2 eV. Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

  18. Fractionation of humic acids according to their hydrophobicity, size, and charge-dependent mobility by the salting-out method

    NASA Astrophysics Data System (ADS)

    Zavarzina, A. G.; Vanifatova, N. G.; Stepanov, A. A.

    2008-12-01

    Humic acids (HAs) represent heterogeneous and polydisperse mixture of molecules that differ in their chemical structure, composition, and functional properties. Fractionation of HAs is of key importance for understanding their interactions with various organic and inorganic compounds, for studying their physiological activity, and for predicting their behavior in natural environments and agroecosystems. Existing fractionation methods are rather laborious and time consuming, which limits their application in fundamental science and industry. It is shown that fractionation of humic acids with ammonium sulfate ensures their preparative separation with respect to (a) hydrophobicity, (b) molecular size, and (c) charge dependent on the amount of functional groups. Salting out at the lowest and highest degrees of saturation with ammonium sulfate, upon which precipitation of the molecules occurs, makes it possible to separate humic acids into functionally different high-molecular-weight/hydrophobic and low-molecular-weight/hydrophilic fractions. The first fraction is characterized by a lower electrophoretic mobility than the second fraction. The weight percentage of the components coagulated at the lowest degree of salt saturation can be used as a quantitative parameter for comparing hydrophobic properties of humic acids. Salting out is recommended as a fast, simple, and cheap alternative to chromatographic methods for preparative separation of humic acids if large amounts of functionally different fractions need to be obtained.

  19. Photo-induced isotopic fractionation

    NASA Astrophysics Data System (ADS)

    Miller, Charles E.; Yung, Yuk L.

    2000-12-01

    This paper presents a systematic method for the analysis of photo-induced isotopic fractionation. The physical basis for this fractionation mechanism centers on the fact that isotopic substitution alters the energy levels, molecular symmetries, spin statistical weights and other fundamental molecular properties, producing spectroscopic signatures distinguishable from that of the parent isotopomer. These mass-dependent physical properties are identical to those invoked by Urey to explain stable isotope fractionation in chemical systems subject to thermodynamic equilibrium. Photo-induced isotopic fractionation is a completely general phenomenon and should be observable in virtually all gas phase photochemical systems. Water photo-induced isotopic fractionation has been examined in detail using experimental and theoretical data. These results illustrate the salient features of this fractionation mechanism for molecules possessing continuous UV absorption spectra and unit photodissociation quantum yields. Using the photo-induced isotopic fractionation methodology in conjunction with standard photochemical models, we predict substantial deuterium enrichment of water vapor in the planetary atmospheres of Earth and Mars.

  20. Injection of deuterium pellets

    SciTech Connect

    Sorensen, H.; Andersen, P.; Andersen, S.A.; Andersen, V.; Nordskov-Nielsen, A.; Sass, B.; Weisberg, K.V.

    1984-09-01

    A discussion is given of the work done at Riso National Laboratory on the design and construction of deuterium pellet injectors. A pellet injection system made for the TFR tokamak at Fontenay-aux-Roses, Paris is described. 0.12-mg pellets are injected with velocities of around 600-700 m/s through a 5-m long guide tube. Next some of the details of a new light gas gun are given; with this gun, hydrogen pellets are accelerated to velocities above 1400 m/s, deuterium pellets to velocities above 1300 m/s and neon pellets to velocities above 550 m/s. Finally, a new acceleration method where a pellet should be accelerated by means of a magnetically stabilised electrical discharge is discussed, and a set up for measuring of the pellet size by means of a microwave cavity is outlined.

  1. Kaon Electroproduction on Deuterium

    SciTech Connect

    David Abbott; Abdellah Ahmidouch, Pawel Ambrozewicz; Chris Armstrong; John Arrington; K. Assamagan; Kevin Bailey; Oliver K. Baker; Shelton Beedoe; Elizabeth Beise; Herbert Breuer; Roger Carlini; Jinseok Cha; G. Collins; C. Cothran; W.J. Cummings; Samuel Danagoulian; Fraser Duncan; Jim Dunne; Dipangkar Dutta; Tom Eden; Rolf Ent; Lars Ewell; H.T. Fortune; Haiyan Gao; Donald Geesaman; Kenneth Gustafsson; Paul Gueye; Jens-Ole Hansen; Wendy Hinton; Hal Jackson; Cynthia Keppel; Andi Klein; D. Koltenok; David Mack; Richard Madey; Pete Markowitz; C.J. Martoff; David Meekins; Joseph Mitchell; R. Mohring; Hamlet Mkrtchyan; S.K. Mtingwa; Tom O'Neill; Gabriel Niculescu; Ioana Niculescu; Dave Potterveld; John Price; Philip Roos; Brian Raue; J.J. Reidy; Juerg Reinhold; G. Savage; Reyad Sawafta; J.P. Schiffer; Ralph Segel; Stepan Stepanyan; V. Tadevosian; Liguang Tang; B. Terburg; Stephen Wood; Chen Yan; Ben Zeidman; Beni Zihlmann

    1998-08-01

    Kaon electroproduction on deuterium and hydrogen targets has been measured at beam energies of 3.245 and 2.445GeV and momentum transfer Q{sup 2}=0.38 and O.5(GeV/c ){sup 2} Associated production off a proton in the deuteron exhibits a quasifree production mechanism. The electroproduction of a Sigma - off the neutron could be extracted for the first time with reasonable errors.

  2. Coil fraction-dependent phase behaviour of a model globular protein–polymer diblock copolymer

    SciTech Connect

    Thomas, Carla S.; Olsen, Bradley D.

    2014-01-01

    The self-assembly of the model globular protein–polymer block copolymer mCherry-b-poly(N-isopropyl acrylamide) is explored across a range of polymer coil fractions from 0.21 to 0.82 to produce a phase diagram for these materials as a function of molecular composition. Overall, four types of morphologies were observed: hexagonally packed cylinders, perforated lamellae, lamellae, and disordered nanostructures. Across all coil fractions and morphologies, a lyotropic re-entrant order–disorder transition in water was observed, with disordered structures below 30 wt% and above 70 wt% and well-ordered morphologies at intermediate concentrations. Solid state samples prepared by solvent evaporation show moderately ordered structures similar to those observed in 60 wt% solutions, suggesting that bulk structures result from kinetic trapping of morphologies which appear at lower concentrations. While highly ordered cylindrical nanostructures are observed around a bioconjugate polymer volume fraction of 0.3 and well-ordered lamellae are seen near a volume fraction of 0.6, materials at lower or higher coil fractions become increasingly disordered. Notable differences between the phase behaviour of globular protein–polymer block copolymers and coil–coil diblock copolymers include the lack of spherical nanostructures at either high or low polymer coil fractions as well as shifted phase boundaries between morphologies which result in an asymmetric phase diagram.

  3. Coil fraction-dependent phase behaviour of a model globular protein-polymer diblock copolymer.

    PubMed

    Thomas, Carla S; Olsen, Bradley D

    2014-05-01

    The self-assembly of the model globular protein-polymer block copolymer mCherry-b-poly(N-isopropyl acrylamide) is explored across a range of polymer coil fractions from 0.21 to 0.82 to produce a phase diagram for these materials as a function of molecular composition. Overall, four types of morphologies were observed: hexagonally packed cylinders, perforated lamellae, lamellae, and disordered nanostructures. Across all coil fractions and morphologies, a lyotropic re-entrant order-disorder transition in water was observed, with disordered structures below 30 wt% and above 70 wt% and well-ordered morphologies at intermediate concentrations. Solid state samples prepared by solvent evaporation show moderately ordered structures similar to those observed in 60 wt% solutions, suggesting that bulk structures result from kinetic trapping of morphologies which appear at lower concentrations. While highly ordered cylindrical nanostructures are observed around a bioconjugate polymer volume fraction of 0.3 and well-ordered lamellae are seen near a volume fraction of 0.6, materials at lower or higher coil fractions become increasingly disordered. Notable differences between the phase behaviour of globular protein-polymer block copolymers and coil-coil diblock copolymers include the lack of spherical nanostructures at either high or low polymer coil fractions as well as shifted phase boundaries between morphologies which result in an asymmetric phase diagram. PMID:24695642

  4. A molecular dynamic model for analyzing concentrations of electrolytes: Fractional molar dependences of microstructure properties

    NASA Astrophysics Data System (ADS)

    Khalansky, D.; Popova, E.; Gladyshev, P.; Dushanov, E.; Kholmurodov, Kh.

    2014-12-01

    Aqueous electrolyte solutions play an important role in many electrophysical and chemical processes in aerospace technology and industrial applications. As noncovalent interactions, the interactions between ions are crucially important for biomolecular structures as well (protein structure folding, molecular level processes followed by ionic pair correlations, the formation of flexible hydrate shells, and so on). Specifically, ions (cations and anions with the same valence charges) can form stable pairs if their sizes match. The formation of ionic pairs can substantially affect the thermodynamic stabilities of proteins in the alkali salts physiologically present in the human body. Research aims and problems impose severe demands on readjustments of the ionic force fields and potential parameters developed to describe aqueous solutions and electrolytic systems. Ionic solutions and their interaction with biomolecules have been observed for over 100 years [1], but the behavior of such solutions remains poorly studied today. New data obtained in this work deals with parameterization strategies and adjustments for the ionic force fields of the alkali cations and halide anions that should be helpful in biomolecular research. Using molecular dynamics (MD) models, four electrolytic systems (HCl-H2O, LiCl-H2O, NaCl-H2O, and KCl-H2O) are investigated as binary mixtures of water and cations and anions, respectively. The intermolecular interaction parameters are varied for two of the four model electrolytes (HCl-H2O and NaCl-H2O) to simulate the possibility of different ionic shells forming during interaction with water. It is found that varying the potential parameters strongly affects the dynamic and structural characteristics of electrolyte systems. MD simulations are performed in the temperature range of 300 to 600 K with a step of 50 K. MD simulations for all electrolyte models (HCl-H2O, LiCl-H2O, NaCl-H2O, KCl-H2O) are also conducted for different molar fractions of

  5. Effects of deuterium oxide on cell growth and vesicle speed in RBL-2H3 cells

    PubMed Central

    Triplett, Ashley R.

    2014-01-01

    For the first time we show the effects of deuterium oxide on cell growth and vesicle transport in rat basophilic leukemia (RBL-2H3) cells. RBL-2H3 cells cultured with 15 moles/L deuterium showed decreased cell growth which was attributed to cells not doubling their DNA content. Experimental observations also showed an increase in vesicle speed for cells cultured in deuterium oxide. This increase in vesicle speed was not observed in deuterium oxide cultures treated with a microtubule-destabilizing drug, suggesting that deuterium oxide affects microtubule-dependent vesicle transport. PMID:25237603

  6. Dynamics of deuterium implanted in boron coating film for wall conditioning

    NASA Astrophysics Data System (ADS)

    Nakahata, Toshihiko; Yoshikawa, Akira; Oyaidzu, Makoto; Oya, Yasuhisa; Ishimoto, Yuki; Kizu, Kaname; Yagyu, Jyunichi; Ashikawa, Naoko; Nishimura, Kiyohiko; Miya, Naoyuki; Okuno, Kenji

    2007-08-01

    Retention and desorption behavior of deuterium implanted into pure boron films has been studied by means of the secondary ion mass spectroscopy. It was found that the process controlling deuterium desorption depended on the temperature. At stage 1, below 573 K, the desorption of deuterium from B-D-B bonds dominated and its diffusion was the rate-determining process. Above 573 K, deuterium was mainly desorbed from B-D bonds, and recombination was the rate-determining process. The effective molecular recombination rate constant of deuterium bound to boron associated with B-D bond was determined by an isothermal annealing experiment.

  7. Lamb shift in muonic deuterium

    SciTech Connect

    Gorchtein, Mikhail; Vanderhaeghen, Marc; Carlson, Carl E.

    2013-11-07

    We consider the two-photon exchange contribution to the 2P-2S Lamb shift in muonic deuterium in the framework of forward dispersion relations. The dispersion integrals are evaluated with minimal model dependence using experimental data on elastic deuteron form factors and inelastic electron-deuteron scattering, both in the quasielastic and hadronic range. The subtraction constant that is required to ensure convergence of the dispersion relation for the forward Compton amplitude T{sub 1} (ν,Q{sup 2}) is related to the deuteron magnetic polarizability β(Q{sup 2}) and represents the main source of uncertainty in our analysis. We obtain for the Lamb shift ΔE{sub 2P-2S} = 1.620±0.190 meV and discuss ways to further reduce this uncertainty.

  8. Mass Dependence of Iron Isotope Fractionation in Fe(II)-Fe(III) Electron Exchange Equilibration

    NASA Astrophysics Data System (ADS)

    Fujii, Yasuhiko; Kim, Sang-Ho; Nomura, Masao; Kawakami, Fumiaki

    2013-02-01

    A one hundred meter long ion-exchange chromatograph was used to establish rigorously the mass effects in the iron isotope fractionation in the Fe(II)-Fe(III) electron exchange equilibration.We used a highly porous, strongly basic anion exchange resin packed in glass columns. The abundance ratios of all natural iron isotopes, 54Fe, 56Fe, 57Fe, and 58Fe, in the effluent at the iron adsorption band boundary were measured with a mass spectrometer. The enrichment correlations among these isotopes were analyzed by three-isotope plots. The results clearly showed that the isotope fractionation of Fe(II)-Fe(III) is governed by the normal mass effect; the iron isotope fractionation is not proportional to the nuclear size, but proportional to the reduced mass difference of the pair of iron isotopes.

  9. Hydrogen and deuterium diffusion in vanadium-titanium alloys

    NASA Astrophysics Data System (ADS)

    Peterson, D. T.; Herro, H. M.

    1987-02-01

    Hydrogen and deuterium diffusion coefficients were measured in vanadium-titanium alloys, containing up to 30 at. pct Ti, by Boltzmann-Matano techniques. Hydrogen and deuterium diffusivity decreased rapidly with titanium concentration. The diffusion coefficients showed an Arrhenius temperature dependence in each alloy between 230 and 473 K with activation energies that increased with titanium concentration. The diffusion coefficient decreased linearly with hydrogen concentration in all alloys. The terminal solid solubilities increased markedly with titanium concentration with deuterium showing a larger terminal solid solubility than hydrogen below ten percent titanium. The diffusion results do not fit a localized deep trapping of hydrogen by the titanium atoms.

  10. Measurement of gluconeogenesis using glucose fragments and mass spectrometry after ingestion of deuterium oxide.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report a new method to measure the fraction of glucose derived from gluconeogenesis using gas chromatography-mass spectrometry and positive chemical ionization. After ingestion of deuterium oxide by subjects, glucose derived from gluconeogenesis is labeled with deuterium. Our calculations of gluc...

  11. Trapping deuterium atoms

    SciTech Connect

    Wiederkehr, A. W.; Hogan, S. D.; Lambillotte, B.; Andrist, M.; Schmutz, H.; Agner, J.; Salathe, Y.; Merkt, F.

    2010-02-15

    Cold deuterium atoms in a supersonic beam have been decelerated from an initial velocity of 475 m/s to zero velocity in the laboratory frame using a 24-stage Zeeman decelerator. The atoms have been loaded in a magnetic quadrupole trap at a temperature of {approx}100 mK and an initial density of {approx}10{sup 6} cm{sup -3}. Efficient deceleration was achieved by pulsing the magnetic fields in the decelerator solenoids using irregular sequences of phase angles. Trap loading was optimized by monitoring and suppressing the observed reflection of the atoms by the field gradient of the back solenoid of the trap.

  12. More than just halo mass: modelling how the red galaxy fraction depends on multiscale density in an HOD framework

    NASA Astrophysics Data System (ADS)

    Phleps, S.; Wilman, D. J.; Zibetti, S.; Budavári, T.

    2014-03-01

    The fraction of galaxies with red colours depends sensitively on environment, and on the way in which environment is measured. To distinguish competing theories for the quenching of star formation, a robust and complete description of environment is required, to be applied to a large sample of galaxies. The environment of galaxies can be described using the density field of neighbours on multiple scales - the multiscale density field. We are using the Millennium simulation and a simple halo occupation distribution (HOD) prescription which describes the multiscale density field of Sloan Digital Sky Survey DR7 galaxies to investigate the dependence of the fraction of red galaxies on the environment. Using a volume-limited sample, where we have sufficient galaxies in narrow density bins, we have more dynamic range in halo mass and density for satellite galaxies than for central galaxies. Therefore, we model the red fraction of central galaxies as a constant while we use a functional form to describe the red fraction of satellites as a function of halo mass which allows us to distinguish a sharp from a gradual transition. While it is clear that the data can only be explained by a gradual transition, an analysis of the multiscale density field on different scales suggests that colour segregation within the haloes is needed to explain the results. We also rule out a sharp transition for central galaxies, within the halo mass range sampled.

  13. Dependence of the Broad Absorption Line Quasar Fraction on Radio Luminosity

    NASA Astrophysics Data System (ADS)

    Shankar, Francesco; Dai, Xinyu; Sivakoff, Gregory R.

    2008-11-01

    We find that the fraction of classical broad absorption line quasars (BALQSOs) among the FIRST radio sources in the Sloan Data Release 3, is 20.5+ 7.3-5.9% at the faintest radio powers detected (L1.4 GHz ~ 1032 erg s-1), and rapidly drops to lesssim8% at L1.4 GHz ~ 3 × 1033 erg s-1. Similarly, adopting the broader absorption index (AI) definition of Trump et al., we find the fraction of radio BALQSOs to be 44+ 8.1-7.8%, reducing to 23.1+ 7.3-6.1% at high luminosities. While the high fraction at low radio power is consistent with the recent near-IR estimates by Dai et al., the lower fraction at high radio powers is intriguing and confirms previous claims based on smaller samples. The trend is independent of the redshift range, the optical and radio flux selection limits, or the exact definition of a radio match. We also find that at fixed optical magnitude, the highest bins of radio luminosity are preferentially populated by non-BALQSOs, consistent with the overall trend. We do find, however, that those quasars identified as AI-BALQSOs but not under the classical definition do not show a significant drop in their fraction as a function of radio power, further supporting independent claims that these sources, characterized by lower equivalent width, may represent an independent class from the classical BALQSOs. We find the balnicity index, a measure of the absorption trough in BALQSOs, and the mean maximum wind velocity to be roughly constant at all radio powers. We discuss several plausible physical models which may explain the observed fast drop in the fraction of the classical BALQSOs with increasing radio power, although none is entirely satisfactory. A strictly evolutionary model for the BALQSO and radio emission phases requires a strong fine-tuning to work, while a simple geometric model, although still not capable of explaining polar BALQSOs and the paucity of FRII BALQSOs, is statistically successful in matching the data if part of the apparent radio

  14. The extent, time course, and fraction size dependence of mouse spinal cord recovery from radiation injury

    SciTech Connect

    Lavey, R.S.; Taylor, M.G.; Tward, J.D.

    1994-10-15

    This experiment was designed to assess: (a) the influence of fraction size and time interval between fractions on the tolerance of the spinal cord to high cumulative doses of radiation; and (b) the influence of the long-term recovery process on the tolerance of the spinal cord to reirradiation. The T10-L2 level of the spinal cord of C3Hf mice was irradiated using a conventionally fractionated regimen of 2.0 Gy once daily, a prolonged fractionated regimen of 1.2 Gy once daily, a hyperfractionated regimen of 1.2 Gy twice daily, or a single dose of 12 Gy followed 0-190 days later by a second dose of 5-20 Gy. Mice in the multifractionated regimen groups were given a single 15 Gy top-up- dose 24 h after reaching a cumulative fractionated dose of 24-70 Gy. Hind limb strength was measured weekly for 2 years after the completion of irradiation. Paralysis occurred in a bimodal time distribution, with peaks at 5-10 months and 15-23 months after the completion of irradiation. The cumulative radiation dose was directly associated with the incidence of paralysis in each radiation schedule (p<0.0001) and inversely associated with the time to onset of paralysis in the 1.2 Gy b.i.d. (p = 0.0001) and 2.0 Gy q.d. schedules (p = 0.03). The median latency of paralysis in each group was inversely associated with the incidence of paralysis in that group (p =<0.001). Decreasing the fraction size from 2.0 to 1.2 Gy once daily markedly increased the radiation tolerance of the spinal cord (p <0.0001), consistent with a very small alpha-beta value of -0.30 Gy ({approximately}95% confidence interval -0.72, +0.18) in the linear-quadratic model. Decreasing the time interval from 24 h to alternating 8 and 16 h periods produced an offsetting diminuation in cord tolerance (p <0.0001). 36 refs., 5 figs., 6 tabs.

  15. Temperature Dependence and Recoil-free Fraction Effects in Olivines Across the Mg-Fe Solid Solution

    NASA Technical Reports Server (NTRS)

    Sklute, E. C.; Rothstein, Y.; Dyar, M. D.; Schaefer, M. W.; Menzies, O. N.; Bland, P. A.; Berry, F. J.

    2005-01-01

    Olivine and pyroxene are the major ferromagnesian minerals in most meteorite types and in mafic igneous rocks that are dominant at the surface of the Earth. It is probable that they are the major mineralogical components at the surface of any planetary body that has undergone differentiation processes. In situ mineralogical studies of the rocks and soils on Mars suggest that olivine is a widespread mineral on that planet s surface (particularly at the Gusev site) and that it has been relatively unaffected by alteration. Thus an understanding of the characteristics of Mossbauer spectra of olivine is of great importance in interpreting MER results. However, variable temperature Mossbauer spectra of olivine, which are needed to quantify recoil-free fraction effects and to understand the temperature dependence of olivine spectra, are lacking in the literature. Thus, we present here a study of the temperature dependence and recoil-free fraction of a series of synthetic olivines.

  16. Dependence of the hybridization parameter on nitrogen molar fraction in nitrogen-containing GaPN solid solutions

    NASA Astrophysics Data System (ADS)

    Nikitina, E. V.; Sobolev, M. S.; Pirogov, E. V.; Egorov, A. Yu.

    2013-12-01

    Heterostructures with GaP1 - x N x layers synthesized by molecular beam epitaxy on GaP(001) substrates have been studied by photoluminescence and X-ray diffraction measurement. The results are compared to parameters calculated using the band anticrossing (BAC) model. Results of this comparative study lead to the conclusion that the hybridization parameter of GaP1 - x N x depends on the molar fraction of nitrogen in the solid solution.

  17. Time-Dependent Regional Myocardial Strains in Patients with Heart Failure with a Preserved Ejection Fraction

    PubMed Central

    Smith, Shane P.; Secomb, Timothy W.; Hong, Brian D.; Moulton, Michael J.

    2016-01-01

    Objectives. To better understand the etiology of HFpEF in a controlled human population, regional time-varying strains were computed using echocardiography speckle tracking in patients with heart failure with a preserved ejection fraction and normal subjects. Methods. Eleven normal volunteers and ten patients with echo-graded diastolic dysfunction and symptoms of heart failure were imaged with echocardiography and longitudinal, circumferential, and rotational strains were determined using speckle-tracking. Diastolic strain rate was also determined. Patient demographics and echo-derived flows, volumes, and pressures were recorded. Results. Peak longitudinal and circumferential strain was globally reduced in patients (p < 0.001), when compared to controls. The patients attained peak longitudinal and circumferential strain at a consistently later point in systole than controls. Rotational strains were not different in most LV regions. Early diastolic strain rate was significantly reduced in the patients (p < 0.001). LV mass and wall thickness were significantly increased in the patients; however ejection fraction was preserved and stroke volume was diminished (p < 0.001). Conclusions. This study shows that patients with HFpEF have reduced early diastolic strain rate and reduced peak strain that is regionally homogeneous and that they also utilize a longer fraction of systole to achieve peak axial strains. PMID:27042673

  18. Hydrogen and deuterium diffusion in vanadium alloys

    SciTech Connect

    Herro, H.M.

    1982-01-01

    Hydrogen and deuterium diffusion coefficients were measured between 473 and 230 K in alloys of vanadium containing titanium or niobium. Boltzmann-Matano techniques allowed the measurement of the hydrogen concentration dependence of the diffusion coefficient. In addition, one of these techniques permitted a determination of the terminal hydrogen solid solubility which was greatly increased by alloying. Both the hydrogen and deuterium diffusion coefficients were found to decrease with hydrogen isotope concentration in all alloys at all temperatures. The effect of niobium additions was to markedly reduce the rate of hydrogen migration to a minimum in the 75 at. pct. Nb alloy. The rate of hydrogen migration decreased with titanium concentration up to 30 at. pct. Ti, the highest concentration examined in that alloy system. The diffusion coefficients exhibited an Arrhenius temperature dependence and the resulting diffusion activation energy and D/sub o/ values both increased with titanium and with niobium concentration to a maximum of 75 at. pct. Nb. Deuterium diffusion activation energies were larger than corresponding hydrogen values in all alloys. The diffusion behavior found in these alloys is not well represented by current local deep trapping models.

  19. Reading skill-fractional anisotropy relationships in visuospatial tracts diverge depending on socioeconomic status.

    PubMed

    Gullick, Margaret M; Demir-Lira, Özlem Ece; Booth, James R

    2016-07-01

    Low socioeconomic status (SES) has been repeatedly linked with decreased academic achievement, including lower reading outcomes. Some lower SES children do show skills and scores commensurate with those of their higher SES peers, but whether their abilities stem from the same systems as high SES children or are based on divergent strategies is unknown. We here investigated a potential interactive relationship between SES and real-word reading skill in the white matter in 42 typically developing children. SES was determined based on parental education; reading skill and age were not significantly related to SES. There was a significant neural interaction: Clusters in the bilateral inferior longitudinal fasciculus (ILF), left superior longitudinal fasciculus, and left corticospinal tract demonstrated interactive skill-SES relationships in fractional anisotropy. Follow-up analyses demonstrated that higher SES children showed a positive relationship between fractional anisotropy, reflecting tract coherence, and reading skill in left hemisphere tract clusters, whereas lower SES children showed a positive relationship in the right hemisphere homologues. Broadly, the ILF has been demonstrated to support orthographic skill on the left and more general visuospatial processing on the right, so high reading achievement in lower SES children may rely on supplementary visuospatial processing more than for higher SES readers. This pattern is consistent with previous work reporting low SES children's environments to include less rich verbal experience, which may lead them to disproportionately draw on visuospatial skills for success. Further, these results indicate that group SES differences may be best described by an adaptive, not a deficit, model. PMID:27412229

  20. Empirical equations for the temperature dependence of calcite-water oxygen isotope fractionation from 10 to 70°C.

    PubMed

    Demény, Attila; Kele, Sándor; Siklósy, Zoltán

    2010-12-30

    Although the temperature dependence of calcite-water oxygen isotope fractionation seems to have been well established by numerous empirical, experimental and theoretical studies, it is still being discussed, especially due to the demand for increased accuracy of paleotemperature calculations. Experimentally determined equations are available and have been verified by theoretical calculations (considered as representative of isotopic equilibrium); however, many natural formations do not seem to follow these relationships implying either that existing fractionation equations should be revised, or that carbonate deposits are seriously affected by kinetic and solution chemistry effects, or late-stage alterations. In order to test if existing fractionation-temperature relationships can be used for natural deposits, we have studied calcite formations precipitated in various environments by means of stable isotope mass spectrometry: travertines (freshwater limestones) precipitating from hot and warm waters in open-air or quasi-closed environments, as well as cave deposits formed in closed systems. Physical and chemical parameters as well as oxygen isotope composition of water were monitored for all the investigated sites. Measuring precipitation temperatures along with oxygen isotope compositions of waters and calcites yielded empirical environment-specific fractionation-temperature equations: [1] 1000 · lnα = 17599/T - 29.64 [for travertines with a temperature range of 30 to 70°C] and [2] 1000 · lnα = 17500/T - 29.89 [for cave deposits for the range 10 to 25°C]. Finally, based on the comparison of literature data and our results, the use of distinct calcite-water oxygen isotopic fractionation relationships and application strategies to obtain the most reliable paleoclimate information are evaluated. PMID:21080503

  1. Isotope fractionation of water during evaporation without condensation.

    PubMed

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

    2005-12-29

    The microscopic events engendering liquid water evaporation have received much attention over the last century, but remain incompletely understood. We present measurements of isotope fractionation occurring during free molecular evaporation from liquid microjets and show that the isotope ratios of evaporating molecules exhibit dramatic differences from equilibrium vapor values, strong variations with the solution deuterium mole fraction, and a clear temperature dependence. These results indicate the existence of an energetic barrier to evaporation and that the evaporation coefficient of water is less than unity. These new insights into water evaporation promise to advance our understanding of the processes that control the formation and lifetime of clouds in the atmosphere. PMID:16375440

  2. Deuterium inventory in Tore Supra: Coupled carbon-deuterium balance

    NASA Astrophysics Data System (ADS)

    Pégourié, B.; Panayotis, S.; Languille, P.; Martin, C.; Dittmar, T.; Gauthier, E.; Hatchressian, J.-C.; Pascal, J.-Y.; Roubin, P.; Ruffe, R.; Tsitrone, E.; Vartanian, S.; Wang, H.; Beauté, A.; Bouvet, J.; Brosset, C.; Bucalossi, J.; Cabié, M.; Caprin, E.; Courtois, X.; Dachicourt, R.; Delchambre, E.; Dominici, C.; Douai, D.; Ekedahl, A.; Gunn, J. P.; Hakola, A.; Jacob, W.; Khodja, H.; Likonen, J.; Linez, F.; Litnovsky, A.; Marandet, Y.; Markelj, S.; Martinez, A.; Mayer, M.; Meyer, O.; Monier-Garbet, P.; Moreau, P.; Negrier, V.; Oddon, P.; Pardanaud, C.; Pasquet, B.; Pelicon, P.; Petersson, P.; Philipps, V.; Possnert, G.; Reiter, D.; Roth, J.; Roure, I.; Rubel, M.; Saint-Laurent, F.; Samaille, F.; Vavpetič, P.

    2013-07-01

    This paper presents an analysis of the carbon-deuterium circulation and the resulting balance in Tore Supra over the period 2002-2007. Carbon balance combines the estimation of carbon gross erosion from spectroscopy, net erosion and deposition using confocal microscopy, lock-in thermography and SEM, and a measure of the amount of deposits collected in the vacuum chamber. Fuel retention is determined from post-mortem (PM) analyses and gas balance (GB) measurements. Special attention was paid to the deuterium outgassed during the nights and weekends of the experimental campaign (vessel under vacuum, Plasma Facing Components at 120 °C) and during vents (vessel at atmospheric pressure, PFCs at room temperature). It is shown that this outgassing is the main process reconciling the PM and GB estimations of fuel retention, closing the coupled carbon-deuterium balance. In particular, it explains why the deuterium concentration in deposits decreases with increasing depth.

  3. Deuterium-tritium experiments on TFTR

    NASA Astrophysics Data System (ADS)

    Bretz, N. L.; Adler, H.; Alling, P.; Ancher, C.; Anderson, H.; Anderson, J. W.; Arunasalam, V.; Ascione, G.; Barnes, C. W.; Barnes, G.; Batha, S.; Bateman, G.; Beer, M.; Bell, M. G.; Bell, R.; Bitter, M.; Blanchard, W.; Brunkhorst, C.; Budny, R.; Bush, C. E.; Camp, R.; Caorlin, M.; Carnevale, H.; Cauffman, S.; Chang, Z.; Cheng, C.; Chrzanowski, J.; Collins, J.; Coward, G.; Cropper, M.; Darrow, D. S.; Daugert, R.; DeLooper, J.; Dorland, W.; Dudek, L.; Duong, H.; Durst, R.; Efthimion, P. C.; Ernst, D.; Evensen, H.; Fisch, N.; Fisher, R.; Fonck, R. J.; Fredd, E.; Fredrickson, E.; Fromm, R.; Fu, G.; Fujita, T.; Furth, H. P.; Garzotto, V.; Gentile, C.; Gilbert, J.; Giola, J.; Gorelenkov, N.; Grek, B.; Grisham, L. R.; Hammett, G.; Hanson, G. R.; Hawryluk, R. J.; Heidbrink, W.; Herrmann, H. W.; Hill, K. W.; Hosea, J.; Hsuan, H.; Hughes, M.; Hulse, R.; Janos, A.; Jassby, D. L.; Jobes, F. C.; Johnson, D. W.; Johnson, L. C.; Kalish, M.; Kamperschroer, J.; Kesner, J.; Kugel, H.; Labik, G.; Lam, N. T.; LaMarche, P. H.; Lawson, E.; LeBlanc, B.; Levine, J.; Levinton, F. M.; Loesser, D.; Long, D.; Loughlin, M. J.; Machuzak, J.; Majeski, R.; Mansfield, D. K.; Marmar, E.; Marsala, R.; Martin, A.; Martin, G.; Mauel, M.; Mazzucato, E.; McCarthy, M. P.; McChesney, J.; McCormack, B.; McCune, D. C.; McGuire, K. M.; McKee, G.; Meade, D. M.; Medley, S. S.; Mikkelsen, D. R.; Mirnov, S. V.; Mueller, D.; Murakami, M.; Murphy, J. A.; Nagy, A.; Navratil, G. A.; Nazikian, R.; Newman, R.; Norris, M.; O'Connor, T.; Oldaker, M.; Ongena, J.; Osakabe, M.; Owens, D. K.; Park, H.; Park, W.; Parks, P.; Paul, S. F.; Pearson, G.; Perry, E.; Persing, R.; Petrov, M.; Phillips, C. K.; Phillips, M.; Pitcher, S.; Pysher, R.; Qualls, A. L.; Raftapoulos, S.; Ramakrishnan, S.; Ramsey, A.; Rasmunsen, D. A.; Redi, M. H.; Renda, G.; Rewoldt, G.; Roberts, D.; Rogers, J.; Rossmassler, R.; Roquemore, A. L.; Ruskov, E.; Sabbaugh, S. A.; Sasao, M.; Schilling, G.; Schivell, J.; Schmidt, G. L.; Scillia, R.; Scott, S. D.; Semenov, I.; Senko, T.; Sesnic, S.; Sissingh, R.; Skinner, C. H.; Snipes, J.; Stencel, J.; Stevens, J.; Stevenson, T.; Stodiek, W.; Strachan, J. D.; Stratton, B. C.; Swanson, J.; Synakowski, E.; Takahashi, H.; Tang, W.; Taylor, G.; Terry, J.; Thompson, M. E.; Tighe, W.; Timberlake, J. R.; Tobita, K.; Towner, H. H.; Tuszewski, M.; Von Halle, A.; Vannoy, C.; Viola, M.; Goeler, S. von; Voorhees, D.; Walters, R. T.; Wester, R.; White, R.; Wieland, R.; Wilgen, J. B.; Williams, M.; Wilson, J. R.; Winston, J.; Wright, K.; Wong, K.-L.; Woskov, P.; Wurden, G. A.; Yamada, M.; Yoshikawa, S.; Young, K. M.; Zarnstorff, M. C.; Zavereev, V.; Zweben, S. J.

    1995-09-01

    A peak fusion power production of 9.3±0.7 MW has been achieved on the Tokamak Fusion Test Reactor (TFTR) in deuterium plasmas heated by co and counter injected deuterium and tritium neutral beams with a total power of 33.7 MW. The ratio of fusion power output to heating power input is 0.27. At the time of the highest neutron flux the plasma conditions are: Te(0)=11.5 keV, Ti(0)=44 keV, ne(0)=8.5×1019 m-3, and =2.2 giving τE=0.24 s. These conditions are similar to those found in the highest confinement deuterium plasmas. The measured D-T neutron yield is within 7% of computer code estimates based on profile measurements and within experimental uncertainties. These plasmas have an inferred central fusion alpha fraction of 0.2% and central fusion power density of 2 MW/m3 similar to that expected in a fusion reactor. Even though the alpha velocity exceeds the Alfven velocity throughout the time of high neutron output in most high power plasmas, MHD activity is not substantially different from that in comparable deuterium plasmas and Alfven wave activity is low. The measured loss rate of energetic alpha particles is about 3% of the total as expected from alphas which are born on unconfined orbits. Compared to pure deuterium plasmas with similar externally applied conditions, the stored energy in electrons and ions is about 25% higher indicating improvements in confinement associated with D-T plasmas and consistent with modest electron heating expected from alpha particles. ICRF heating of D-T plasmas using up to 5.5 MW has resulted in 10 keV increases in central ion and 2.5 keV increases in central electron temperatures in relatively good agreement with code predictions. In these cases heating on the magnetic axis at 2ΩT gave up to 80% of the ICRF energy to ions.

  4. Growth phase dependent hydrogen isotopic fractionation in alkenone-producing haptophytes

    NASA Astrophysics Data System (ADS)

    Wolhowe, M. D.; Prahl, F. G.; Probert, I.; Maldonado, M.

    2009-08-01

    Recent works have investigated use of the hydrogen isotopic composition of C37 alkenones (δDK37s, lipid biomarkers of certain haptophyte microalgae, as an independent paleosalinity proxy. We discuss herein the factors impeding the success of such an application and identify the potential alternative use of δDK37s measurements as a proxy for non-thermal, physiological stress impacts on the U37K' paleotemperature index. Batch-culture experiments with the haptophyte Emiliania huxleyi (CCMP 1742) were conducted to determine the magnitude and variability of the isotopic contrasts between individual C37 alkenones. Further experiments were conducted with Emiliania huxleyi (CCMP 1742) andGephyrocapsa oceanica (PZ3-1) to determine whether, and to what extent, δDK37s varies between the physiological extremes of nutrient-replete exponential growth and nutrient-depleted senescence. Emiliania huxleyi was observed to exhibit an isotopic contrast between di- and tri-unsaturated C37 alkenones (αK37:3-K37:2≈0.97) that is nearly identical to that reported recently by others for environmental samples. Furthermore, this contrast appears to be constant with growth stage. The consistency of the offset across different growth stages suggests that a single, well-defined value for αK37:3-K37:2 may exist and that its use in an isotope mass-balance will allow accurate determination of δD values for individual alkenones without having to rely on time- and labor-intensive chemical separations. The isotopic fractionation between growth medium and C37 alkenones was observed to increase dramatically upon the onset of nutrient-depletion-induced senescence, suggesting that δDK37s may serve as an objective tool for recognizing and potentially correcting, at least semi-quantitatively, for the effects of nutrient stress on U37K' temperature records.

  5. Deuterium Enrichment of PAHs by VUV Irradiation of Interstellar Ices

    NASA Technical Reports Server (NTRS)

    Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Gillette, J. Seb; Zare, Richard N.; DeVincenzi, Donald (Technical Monitor)

    1998-01-01

    Laboratory results demonstrate that polycyclic aromatic hydrocarbons (PAHs) rapidly exchange their hydrogen atoms with those of nearby molecules when they are frozen into low-temperature ices and exposed to vacuum ultraviolet radiation. As a result, PAHs quickly become deuterium-enriched when VUV irradiated in D-containing ices. This mechanism has important consequences for several astrophysical issues owing to the ubiquitous nature of PAHs in the interstellar medium. For example, this process may explain the deuterium enrichments found in PAHs in meteorites and interplanetary dust particles. These results also provide general predictions about the molecular siting of the deuterium on aromatic materials in meteorites if this process produced a significant fraction of their D-enrichment.

  6. An Update on the Non-Mass-Dependent Isotope Fractionation under Thermal Gradient

    NASA Technical Reports Server (NTRS)

    Sun, Tao; Niles, Paul; Bao, Huiming; Socki, Richard; Liu, Yun

    2013-01-01

    Mass flow and compositional gradient (elemental and isotope separation) occurs when flu-id(s) or gas(es) in an enclosure is subjected to a thermal gradient, and the phenomenon is named thermal diffusion. Gas phase thermal diffusion has been theoretically and experimentally studied for more than a century, although there has not been a satisfactory theory to date. Nevertheless, for isotopic system, the Chapman-Enskog theory predicts that the mass difference is the only term in the thermal diffusion separation factors that differs one isotope pair to another,with the assumptions that the molecules are spherical and systematic (monoatomic-like structure) and the particle collision is elastic. Our previous report indicates factors may be playing a role because the Non-Mass Dependent (NMD) effect is found for both symmetric and asymmetric, linear and spherical polyatomic molecules over a wide range of temperature (-196C to +237C). The observed NMD phenomenon in the simple thermal-diffusion experiments demands quantitative validation and theoretical explanation. Besides the pressure and temperature dependency illustrated in our previous reports, efforts are made in this study to address issues such as the role of convection or molecular structure and whether it is a transient, non-equilibrium effect only.

  7. Culture-Dependent and -Independent Methods Capture Different Microbial Community Fractions in Hydrocarbon-Contaminated Soils

    PubMed Central

    Stefani, Franck O. P.; Bell, Terrence H.; Marchand, Charlotte; de la Providencia, Ivan E.; El Yassimi, Abdel; St-Arnaud, Marc; Hijri, Mohamed

    2015-01-01

    Bioremediation is a cost-effective and sustainable approach for treating polluted soils, but our ability to improve on current bioremediation strategies depends on our ability to isolate microorganisms from these soils. Although culturing is widely used in bioremediation research and applications, it is unknown whether the composition of cultured isolates closely mirrors the indigenous microbial community from contaminated soils. To assess this, we paired culture-independent (454-pyrosequencing of total soil DNA) with culture-dependent (isolation using seven different growth media) techniques to analyse the bacterial and fungal communities from hydrocarbon-contaminated soils. Although bacterial and fungal rarefaction curves were saturated for both methods, only 2.4% and 8.2% of the bacterial and fungal OTUs, respectively, were shared between datasets. Isolated taxa increased the total recovered species richness by only 2% for bacteria and 5% for fungi. Interestingly, none of the bacteria that we isolated were representative of the major bacterial OTUs recovered by 454-pyrosequencing. Isolation of fungi was moderately more effective at capturing the dominant OTUs observed by culture-independent analysis, as 3 of 31 cultured fungal strains ranked among the 20 most abundant fungal OTUs in the 454-pyrosequencing dataset. This study is one of the most comprehensive comparisons of microbial communities from hydrocarbon-contaminated soils using both isolation and high-throughput sequencing methods. PMID:26053848

  8. Determination of mass-dependent isotopic fractionation of cerium and neodymium in geochemical samples by MC-ICPMS.

    PubMed

    Ohno, Takeshi; Hirata, Takafumi

    2013-01-01

    We have developed a new analytical method to determine the mass-dependent isotopic fractionations on Ce and Nd in geochemical samples. Mass discrimination effects on Ce and Nd were externally corrected by normalizing (149)Sm/(147)Sm and (153)Eu/(151)Eu, being 0.92124 and 1.0916, respectively based on an exponential law. The reproducibility of the isotopic ratio measurements on (142)Ce/(140)Ce, (146)Nd/(144)Nd and (148)Nd/(144)Nd were 0.08‰ (2SD, n = 25), 0.06‰ (2SD, n = 39) and 0.12‰ (2SD, n = 39), respectively. The present technique was applied to determine the variations of the Ce and Nd isotopic ratios for five geochemical reference materials (igneous rocks, JB-1a and JA-2; sedimentary rocks, JMn-1, JCh-1 and JDo-1). The resulting ratios for two igneous rocks (JB-1a and JA-2) and two sedimentary rocks (JMn-1 and JCh-1) did not vary significantly among the samples, whereas the Ce and Nd isotope ratios for the carbonate samples (JDo-1) were significantly higher than those for igneous and sedimentary rock samples. The 1:1 simple correlation between δ(142)Ce and δ(146)Nd indicates that there were no significant difference in the degree of isotopic fractionation between the Ce and Nd. This suggests that the isotopic fractionation for Ce found in the JDo-1 could be induced by geochemical or physicochemical processes without changing the oxidation status of Ce, since the redox-reaction can produce larger isotopic fractionation than the reactions without changing the oxidation state. The variations in the Ce and Nd isotope ratios for geochemical samples could provide new information concerning the physico-chemical processes of the sample formation. PMID:23303084

  9. Shock compression of precompressed deuterium

    SciTech Connect

    Armstrong, M R; Crowhurst, J C; Zaug, J M; Bastea, S; Goncharov, A F; Militzer, B

    2011-07-31

    Here we report quasi-isentropic dynamic compression and thermodynamic characterization of solid, precompressed deuterium over an ultrafast time scale (< 100 ps) and a microscopic length scale (< 1 {micro}m). We further report a fast transition in shock wave compressed solid deuterium that is consistent with the ramp to shock transition, with a time scale of less than 10 ps. These results suggest that high-density dynamic compression of hydrogen may be possible on microscopic length scales.

  10. Growth phase dependent hydrogen isotopic fractionation in alkenone-producing haptophytes

    NASA Astrophysics Data System (ADS)

    Wolhowe, M. D.; Prahl, F. G.; Probert, I.; Maldonado, M.

    2009-04-01

    Several recent works have investigated use of the hydrogen isotopic composition of C37 alkenones (δDK37s), lipid biomarkers of certain haptophyte microalgae, as an independent paleosalinity proxy. We discuss herein the factors impeding the success of such an application and identify the potential alternative use of δDK37s measurements as a proxy for non-thermal, physiological stress impacts on the U37K' paleotemperature index. Batch-culture experiments with the haptophyte Emiliania huxleyi (CCMP 1742) were conducted to determine the magnitude and variability of the isotopic contrasts between individual C37 alkenones, an analytical impediment to the use of δDK37s in any paleoceanographic context. Further experiments were conducted with Emiliania huxleyi (CCMP 1742) and Gephyrocapsa oceanica (PZ3-1) to determine whether, and to what extent, δDK37s varies between the physiological extremes of nutrient-replete exponential growth and nutrient-depleted senescence, the basis for our proposed use of the measurement as an indicator of stress. Emiliania huxleyi exhibited an isotopic contrast between di- and tri-unsaturated C37 alkenones (αK37:3-K37:2≈0.97) that is nearly identical to that reported recently by others for environmental samples. Furthermore, this contrast appears to be constant with growth stage. The consistency of the offset across different growth stages suggests that a single, well-defined value for αK37:3-K37:2 exists and that its use in an isotope mass-balance will allow accurate determination of δD values for individual alkenones without having to rely on time- and labor-intensive chemical separations. The isotopic fractionation between growth medium and C37 alkenones was observed to increase dramatically upon the onset of nutrient-depletion-induced senescence, suggesting that δDK37s may serve as an objective tool for recognizing and potentially correcting, at least semi-quantitatively, for the effects of nutrient stress on U37K' temperature

  11. There is no temperature dependence of net biochemical fractionation of hydrogen and oxygen isotopes in tree-ring cellulose.

    PubMed

    Roden, J S; Ehleringer, J R

    2000-01-01

    The isotopic composition of tree-ring cellulose was obtained over a two-year period from small diameter, riparian zone trees along an elevational transect in Big Cottonwood Canyon, Utah, USA to test for a possible temperature dependence of net biological fractionation during cellulose synthesis. The isotope ratios of stream water varied by only 3.6% and 0.2% in deltaD and delta18O, respectively, over an elevation change of 810m. The similarity in stream water and macroenvironment over the short (13km) transect produced nearly constant stem and leaf water deltaD and delta18O values. In addition, what few seasonal variations observed in the isotopic composition of source water and atmospheric water vapor or in leaf water evaporative enrichment were experienced equally by all sites along the elevational transect. The temperature at each site along the transect spanned a range of > or = 5 degrees C as calculated using the adiabatic lapse rate. Since the deltaD and delta18O values of stem and leaf water varied little for these trees over this elevation/temperature transect, any differences in tree-ring cellulose deltaD and delta18O values should have been associated with temperature effects on net biological fractionation. However, the slopes of the regressions of elevation versus the deltaD and delta18O values of tree-ring cellulose were not significantly different from zero indicating little or no temperature dependence of net biological fractionation. Therefore, cross-site climatic reconstruction studies using the isotope ratios of cellulose need not be concerned that temperatures during the growing season have influenced results. PMID:11501707

  12. Laser-driven polarized hydrogen and deuterium internal targets

    SciTech Connect

    Jones, C.E.; Fedchak, J.A.; Kowalczyk, R.S.

    1995-08-01

    After completing comprehensive tests of the performance of the source with both hydrogen and deuterium gas, we began tests of a realistic polarized deuterium internal target. These tests involve characterizing the atomic polarization and dissociation fraction of atoms in a storage cell as a function of flow and magnetic field, and making direct measurements of the average nuclear tensor polarization of deuterium atoms in the storage cell. Transfer of polarization from the atomic electron to the nucleus as a result of D-D spin-exchange collisions was observed in deuterium, verifying calculations suggesting that high vector polarization in both hydrogen and deuterium can be obtained in a gas in spin temperature equilibrium without inducing RF transitions between the magnetic substates. In order to improve the durability of the system, the source glassware was redesigned to simplify construction and installation and eliminate stress points that led to frequent breakage. Improvements made to the nuclear polarimeter, which used the low energy {sup 3}H(d,n){sup 4}He reaction to analyze the tensor polarization of the deuterium, included installing acceleration lenses constructed of wire mesh to improve pumping conductance, construction of a new holding field coil, and elimination of the Wien filter from the setup. These changes substantially simplified operation of the polarimeter and should have reduced depolarization in collisions with the wall. However, when a number of tests failed to show an improvement of the nuclear polarization, it was discovered that extended operation of the system with a section of teflon as a getter for potassium caused the dissociation fraction to decline with time under realistic operating conditions, suggesting that teflon may not be a suitable material to eliminate potassium from the target. We are replacing the teflon surfaces with drifilm-coated ones and plan to continue tests of the polarized internal target in this configuration.

  13. Studies of quaternary saline lakes-I. Hydrogen isotope fractionation in saline minerals

    USGS Publications Warehouse

    Matsuo, S.; Friedman, I.; Smith, G.I.

    1972-01-01

    Borax, gaylussite, nahcolite and trona were synthesized in aqueous solution at temperatures ranging from 8?? to 35??C. Except for borax, deuterium was always depleted in these hydrated minerals relative to the solutions from which they were crystallized. In borax, no significant fractionation was found. The fractionation factor of D H for the trona-water system exhibited a marked temperature dependence. By combining the deuterium contents of trona and the solution from which trona was crystallized, the following thermometer scale was obtained: In ( D H) trona ( D H)water = 1.420 ?? 104 T2 + 23.56 T (1). An attempt to establish a geothermometer based on C13 C12 fractionation between carbonate minerals and carbonate ions in aqueous solution was not successful. ?? 1972.

  14. Mechanistic deductions from multiple kinetic and solvent deuterium isotope effects and pH studies of pyridoxal phosphate dependent carbon-carbon lyases: escherichia coli tryptophan indole-lyase

    SciTech Connect

    Kiick, D.M.; Phillips, R.S.

    1988-09-20

    Analysis of the pH dependence of the kinetic parameters and competitive inhibitor Ki values for tryptophan indole-lyase suggests two enzymic groups must be unprotonated in order to facilitate binding and catalysis of tryptophan. The V/K for tryptophan and the pKi for oxindolyl-L-alanine, a putative transition state analogue and competitive inhibitor, decrease below two pK values of 7.6 and 6.0, while the Ki for L-alanine, also a competitive inhibitor, is 3300-fold larger (20 mM) than that for oxindolyl-L-alanine and increases below a single pK of 7.6. A single pK of 7.6 is also observed in the V/K profile for the alternate substrate, S-methyl-L-cysteine. Therefore, the enzymic group with a pK of 7.6 is responsible for proton abstraction at the 2-position of tryptophan, while the enzymic group with a pK of 6.0 interacts with the indole portion of tryptophan and probably catalyzes formation of the indolenine tautomer of tryptophan (in concert with proton transfer to C-3 of indole from the group with pK 7.6) to facilitate carbon-carbon bond cleavage and elimination of indole. The pH variation of the primary deuterium isotope effects for proton abstraction at the 2-position of tryptophan (DV = 2.5 and D(V/Ktrp) = 2.8) are pH independent, while the Vmax for tryptophan or S-methyl-L-cysteine is the same and also pH independent. Thus, substrates bind only to the correctly protonated form of the enzyme. Further, tryptophan is not sticky, and the pK values observed in both V/K profiles are the correct ones.

  15. Deuterium retention and surface modifications of nanocrystalline tungsten films exposed to high-flux plasma

    NASA Astrophysics Data System (ADS)

    `t Hoen, M. H. J.; Dellasega, D.; Pezzoli, A.; Passoni, M.; Kleyn, A. W.; Zeijlmans van Emmichoven, P. A.

    2015-08-01

    Deuterium retention studies are presented for nanostructured tungsten films exposed to high-flux deuterium plasmas. Thin tungsten films of ∼1 μm thickness were deposited with pulsed laser deposition (PLD) on bulk tungsten. Surface modifications were studied with scanning electron microscopy and deuterium retention with thermal desorption spectroscopy. Three types of PLD films with different densities and crystallinity were studied after exposure to deuterium plasmas. The surface temperature ranged from about 460 K at the periphery to about 520 K in the centre of the targets. The films withstand the intense plasma exposure well and maintain their overall integrity. An increase of deuterium retention is observed with decreasing tungsten density and crystallite size. We found that the filling of these thin films with deuterium is significantly faster than for pre-damaged polycrystalline tungsten. We observed formation of micrometer-sized blisters as well as structures on the nanometer scale, both depending on the layer type.

  16. Influence of Deuterium Treatments on the Polysilicon-Based Metal-Semiconductor-Metal Photodetector.

    PubMed

    Lee, Jae-Sung

    2016-06-01

    The electrical behavior of metal-semiconductor-metal (MSM) Schottky barrier photodetector structure, depending on deuterium treatment, is analyzed by means of the dark current and the photocurrent measurements. Al/Ti bilayer was used as Schottky metal. The deuterium incorporation into the absorption layer, undoped polysilicon, was achieved with annealing process and with ion implantation process, respectively. In the photocurrent-to-dark current ratio measurement, deuterium-ion-implanted photodetector shows over hundred higher than the control device. It means that the heightening of the Schottky barrier and the passivation of grain boundary trap were achieved effectively through the deuterium ion implantation process. PMID:27427689

  17. Mercury (Hg) in meteorites: Variations in abundance, thermal release profile, mass-dependent and mass-independent isotopic fractionation

    NASA Astrophysics Data System (ADS)

    Meier, Matthias M. M.; Cloquet, Christophe; Marty, Bernard

    2016-06-01

    We have measured the concentration, isotopic composition and thermal release profiles of Mercury (Hg) in a suite of meteorites, including both chondrites and achondrites. We find large variations in Hg concentration between different meteorites (ca. 10 ppb to 14,000 ppb), with the highest concentration orders of magnitude above the expected bulk solar system silicates value. From the presence of several different Hg carrier phases in thermal release profiles (150-650 °C), we argue that these variations are unlikely to be mainly due to terrestrial contamination. The Hg abundance of meteorites shows no correlation with petrographic type, or mass-dependent fractionation of Hg isotopes. Most carbonaceous chondrites show mass-independent enrichments in the odd-numbered isotopes 199Hg and 201Hg. We show that the enrichments are not nucleosynthetic, as we do not find corresponding nucleosynthetic deficits of 196Hg. Instead, they can partially be explained by Hg evaporation and redeposition during heating of asteroids from primordial radionuclides and late-stage impact heating. Non-carbonaceous chondrites, most achondrites and the Earth do not show these enrichments in vapor-phase Hg. All meteorites studied here have however isotopically light Hg (δ202Hg = ∼-7 to -1) relative to the Earth's average crustal values, which could suggest that the Earth has lost a significant fraction of its primordial Hg. However, the late accretion of carbonaceous chondritic material on the order of ∼2%, which has been suggested to account for the water, carbon, nitrogen and noble gas inventories of the Earth, can also contribute most or all of the Earth's current Hg budget. In this case, the isotopically heavy Hg of the Earth's crust would have to be the result of isotopic fractionation between surface and deep-Earth reservoirs.

  18. Mass-dependent and mass-independent fractionation of mercury isotopes in precipitation from Guiyang, SW China

    NASA Astrophysics Data System (ADS)

    Wang, Zhuhong; Chen, Jiubin; Feng, Xinbin; Hintelmann, Holger; Yuan, Shengliu; Cai, Hongming; Huang, Qiang; Wang, Shuxiao; Wang, Fengyang

    2015-11-01

    The isotopic composition of mercury (Hg) is increasingly used to constrain the sources and pathways of this metal in the atmosphere. Though China has the highest Hg production, consumption and emission in the world, Hg isotope ratios are rarely reported for Chinese wet deposition. In this study, we examined, for the first time outside North America, both mass-dependent fractionation (MDF, expressed as δ202Hg) and mass-independent fractionation of odd (odd-MIF, Δ199Hg) and even (even-MIF, Δ200Hg) Hg isotopes in 15 precipitation samples collected from September 2012 to August 2013 in Guiyang (SW China). All samples displayed significant negative δ202Hg (-0.44 ∼ -4.27‰), positive Δ199Hg (+0.19 to +1.16‰) and slightly positive Δ200Hg (-0.01‰ to +0.20‰). Potential sources of Hg in precipitation were identified by coupling both MDF and MIF of Hg isotopes with a back-trajectory model. The results showed that local emission from coal-fired power plants and cement plants and western long-range transportation are two main contributing sources, while the contribution of Hg from south wind events would be very limited on an annual basis. The relatively lower Δ200Hg values in Guiyang precipitation may indicate a dilution effect by local sources and/or insignificant even-MIF in the tropopause contribution of this subtropical region. Our study demonstrates the usefulness of isotope fractionation, especially MIF for tracing sources and pathways of Hg in the atmosphere.

  19. Deuterated H3+ as a probe of isotope fractionation in star-forming regions.

    PubMed

    Roberts, Helen; Millar, T J

    2006-11-15

    Observations of molecular D/H ratios in the interstellar medium are used to probe the physical conditions, such as temperature, ionization fraction and the importance of gas-grain reactions. In cold, dense regions, such as cores which are collapsing to form stars, the level of deuterium fractionation depends on the conversion of H3+ into its deuterated isotopologues (H2D+, D2H+ and D3+). The relative abundances of these molecules uniquely probe the centres of these cores where other, heavier, species have frozen onto dust grains. We present models of the deuterium chemistry close to the centre of a pre-stellar core, in the last stage before the star forms, showing the dependence of the observable molecular D/H ratios on the physical parameters and rate coefficients that are assumed. We compare model predictions with the latest observations of these regions. PMID:17015383

  20. Experimental determination of the strain and strain rate dependence of the fraction of plastic work converted to heat

    SciTech Connect

    Hodowany, J.; Ravichandran, G.; Rosakis, A.J.

    1995-12-31

    When metals are deformed dynamically, there is insufficient time for heat generated by plastic deformation to be conducted to the surroundings. Thus, the conversion of plastic work into heat at high strain rates can result in significant temperature increases, which contribute to thermal softening, thereby altering a material`s constitutive response. The fraction of plastic work converted to heat represents the strength of the coupling term between temperature and mechanical fields in thermalmechanical problems involving plastic flow. The experimental determination of this constitutive function is important since it is an integral part of the formulation of coupled thermomechanical field equations. This fraction also plays an important role in failure mode characterization for metals deforming at high rates of strain, such as the formation of adiabatic shear bands. This investigation systematically examines the rate of conversion of plastic work to heat in metals under dynamic loading. Temperature was measured in-situ using an array of high speed In-Sb infrared detectors. The plastic work rate and the heat generation rate were determined directly from experimental data. The ratio of heat generation rate to plastic work rate, i.e., the relative rate at which plastic work is converted to heat, was calculated from this data. The functional dependence of this quantity upon strain and strain rate is reported for 1020 steel, 2024 aluminum, Ti-6Al-4V titanium alloy, and C300 maraging steel.

  1. Deuterium in North Atlantic storm tops

    NASA Technical Reports Server (NTRS)

    Smith, Ronald B.

    1992-01-01

    During the ERICA project in 1989, ice crystals were collected from the tops of two winter storms and one broad cirrus cloud. Deuterium concentration in the storm ice samples, together with a model of isotope fractionation, are used to determine the temperature where the ice was formed. Knowledge of the ice formation temperature allows us to determine whether the ice has fallen or been lofted to the altitude of collection. In both storms, the estimated fall distance decreases upward. In the 21 January storm, the fall distance decreases to zero at the cloud top. In the 23 January storm, the fall distance decreases to zero at a point 2 km below the cloud top and appears to become negative above, indicating lofted ice. Cloud particle data from the cloud tops show an ice-to-vapor ratio greater than one and indicate the presence of particles with small terminal velocities; both observations support the idea of ice lofting. The satellite-derived cloud tops lie well below the actual cloud top (e.g., 2.5 km below on 23 January), indicating that the lofted ice in winter storms may not be detectable from space using IR radiance techniques. A comparison of deuterium in cloud-top ice and clear-air vapor suggests that even in winter, when vertical air motions are relatively weak, lofted ice crystals are the dominant source of water vapor in the upper troposphere.

  2. Deuterium enrichment of the interstellar grain mantle

    NASA Astrophysics Data System (ADS)

    Das, Ankan; Sahu, Dipen; Majumdar, Liton; Chakrabarti, Sandip K.

    2016-01-01

    We carry out Monte Carlo simulation to study deuterium enrichments of interstellar grain mantles under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud regions, very strong radiation fields persists and hardly a few layers of surface species are formed. In translucent cloud regions with a moderate radiation field, significant number of layers would be produced and surface coverage is mainly dominated by photo-dissociation products such as, C, CH3, CH2D, OH and OD. In the intermediate dense cloud regions (having number density of total hydrogen nuclei in all forms ˜2 × 104 cm-3), water and methanol along with their deuterated derivatives are efficiently formed. For much higher density regions (˜106 cm-3), water and methanol productions are suppressed but surface coverages of CO, CO2, O2 and O3 are dramatically increased. We find a very high degree of fractionation of water and methanol. Observational results support a high fractionation of methanol but surprisingly water fractionation is found to be low. This is in contradiction with our model results indicating alternative routes for de-fractionation of water. Effects of various types of energy barriers are also studied. Moreover, we allow grain mantles to interact with various charged particles (such as H+, Fe+, S+ and C+) to study the stopping power and projected range of these charged particles on various target ices.

  3. Deuterium Retention and Physical Sputtering of Low Activation Ferritic Steel

    NASA Astrophysics Data System (ADS)

    T, Hino; K, Yamaguchi; Y, Yamauchi; Y, Hirohata; K, Tsuzuki; Y, Kusama

    2005-04-01

    Low activation materials have to be developed toward fusion demonstration reactors. Ferritic steel, vanadium alloy and SiC/SiC composite are candidate materials of the first wall, vacuum vessel and blanket components, respectively. Although changes of mechanical-thermal properties owing to neutron irradiation have been investigated so far, there is little data for the plasma material interactions, such as fuel hydrogen retention and erosion. In the present study, deuterium retention and physical sputtering of low activation ferritic steel, F82H, were investigated by using deuterium ion irradiation apparatus. After a ferritic steel sample was irradiated by 1.7 keV D+ ions, the weight loss was measured to obtain the physical sputtering yield. The sputtering yield was 0.04, comparable to that of stainless steel. In order to obtain the retained amount of deuterium, technique of thermal desorption spectroscopy (TDS) was employed to the irradiated sample. The retained deuterium desorbed at temperature ranging from 450 K to 700 K, in the forms of DHO, D2, D2O and hydrocarbons. Hence, the deuterium retained can be reduced by baking with a relatively low temperature. The fluence dependence of retained amount of deuterium was measured by changing the ion fluence. In the ferritic steel without mechanical polish, the retained amount was large even when the fluence was low. In such a case, a large amount of deuterium was trapped in the surface oxide layer containing O and C. When the fluence was large, the thickness of surface oxide layer was reduced by the ion sputtering, and then the retained amount in the oxide layer decreased. In the case of a high fluence, the retained amount of deuterium became comparable to that of ferritic steel with mechanical polish or SS 316L, and one order of magnitude smaller than that of graphite. When the ferritic steel is used, it is required to remove the surface oxide layer for reduction of fuel hydrogen retention. Ferritic steel sample was

  4. Mass Dependent and Mass Independent Fractionation of Hg Isotopes and Estimation of Photochemical Loss of Hg in Aquatic Systems

    NASA Astrophysics Data System (ADS)

    Bergquist, B. A.; Blum, J. D.

    2007-12-01

    Mercury is a globally distributed and highly toxic pollutant, the mobility and bioaccumulation of which is dependent on its redox cycling. Hg isotope analysis is an important new tool for identifying Hg sources and tracking Hg transformations in the environment. Most natural samples analyzed for Hg isotopes display mass-dependent isotope fractionation (MDF), but a small body of data suggests that some natural samples also display mass- independent isotope fractionation (MIF) of the odd Hg isotopes. Here we document MIF of Hg isotopes during an important natural process, constrain the potential mechanism of isotope fractionation, and apply the MIF observed in natural samples to quantify the photochemical reduction of Hg species in the environment. Reduction of Hg species to Hg0 vapor is an important pathway for removal of Hg from aqueous systems into the atmosphere and occurs by abiotic and biotic mechanisms. In laboratory experiments, we find that photochemical reduction Hg species by natural sunlight leads to large MIF of the odd isotopes. Also, the relationship between MIF for the two odd isotopes of Hg is significantly different for different photo-reduction pathways. In contrast, both biological reduction (Kritee et al., 2006) and dark abiotic organically-mediated reduction follow MDF. Natural samples from aquatic ecosystems preserve both MDF and MIF. In fish, MDF increases with the size and Hg concentration of fish suggesting MDF may be useful in understanding Hg bioaccumulation. Fish also display a large range in MIF (4‰), and the relationship between the MIF of the two odd isotopes in fish has a similar slope to the slope found for photo-reduction of CH3Hg+. Since fish bioaccumulate CH3Hg+, fish may be recording the extent to which CH3Hg+ is lost via photochemical reduction in an aquatic ecosystem. Fish populations from different locations have different MIF values, but mostly display similar MIF within a given locale. This suggests that MIF is preserved

  5. Mass Dependency of Isotope Fractionation of Gases Under Thermal Gradient and Its Possible Implications for Planetary Atmosphere Escaping Process

    NASA Technical Reports Server (NTRS)

    Sun, Tao; Niles, Paul; Bao, Huiming; Socki, Richard

    2014-01-01

    Physical processes that unmix elements/isotopes of gas molecules involve phase changes, diffusion (chemical or thermal), effusion and gravitational settling. Some of those play significant roles for the evolution of chemical and isotopic compositions of gases in planetary bodies which lead to better understanding of surface paleoclimatic conditions, e.g. gas bubbles in Antarctic ice, and planetary evolution, e.g. the solar-wind erosion induced gas escaping from exosphere on terrestrial planets.. A mass dependent relationship is always expected for the kinetic isotope fractionations during these simple physical processes, according to the kinetic theory of gases by Chapman, Enskog and others [3-5]. For O-bearing (O16, -O17, -O18) molecules the alpha O-17/ alpha O-18 is expected at 0.5 to 0.515, and for S-bearing (S32,-S33. -S34, -S36) molecules, the alpha S-33/ alpha S-34 is expected at 0.5 to 0.508, where alpha is the isotope fractionation factor associated with unmixing processes. Thus, one isotope pair is generally proxied to yield all the information for the physical history of the gases. However, we recently] reported the violation of mass law for isotope fractionation among isotope pairs of multiple isotope system during gas diffusion or convection under thermal gradient (Thermal Gradient Induced Non-Mass Dependent effect, TGI-NMD). The mechanism(s) that is responsible to such striking observation remains unanswered. In our past studies, we investigated polyatomic molecules, O2 and SF6, and we suggested that nuclear spin effect could be responsible to the observed NMD effect in a way of changing diffusion coefficients of certain molecules, owing to the fact of negligible delta S-36 anomaly for SF6.. On the other hand, our results also showed that for both diffusion and convection under thermal gradient, this NMD effect is increased by lower gas pressure, bigger temperature gradient and lower average temperature, which indicate that the nuclear spin effect may

  6. NOTE: On the Deuterium Abundance on Mars and Some Related Problems

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir

    2000-12-01

    Strong fractionation of deuterium in photolysis of H 2O and above the hygropause reduces the production of HD relative to H 2 on Mars by a factor of 3.7 total. The model by Y. L. Yung et al. (1988, Icarus76, 146-159) for deuterium fractionation in chemical reactions on Mars corrected for this factor results in (HD/H 2)/(HDO/H 2O)=0.43. This value may fit the deuterium abundance observed by V. A. Krasnopolsky et al. (1998, Science 280, 1576-1580) if the eddy diffusion coefficient does not depend on solar activity: K=1.4×10 13n-1/2 cm 2 s -1 (model 2). The Mariner 9 observations show very low variability of atomic oxygen at the 1.2 n bar pressure level (h˜125 km) with solar activity. This requires eddy diffusion to be proportional to the solar activity index F10.7: K=( F10.7 cm/30)×10 13n-1/2 cm 2 s -1 (model 1). The fractionation factor for escape of hydrogen isotopes is equal to 0.016 and 0.135 for models 1 and 2. These values have been averaged over the solar cycle. The three-reservoir model for hydrogen isotope fractionation suggested by Krasnopolsky et al. (1998) involves a reservoir composed primarily of water ice in the polar caps that isotopically interacts with the atmosphere. Assuming that water ice is half of the total volume of the polar caps and the polar-layered deposits, the total loss of water from Mars is equal to 65 and 120 m for models 1 and 2, respectively. Along with thermal and nonthermal escape, these values may include the loss of water by oxidation of regolith, if the released hydrogen escaped with isotopic fractionation. Although the solar-wind α particles are the main source of He on Mars, capture of the solar-wind H + and D + ions by Mars has a negligible effect on the thermospheric abundances of H and D. Improved observations of minor components in Mars' thermosphere may resolve the problem of eddy diffusion at various solar activity and choosing between the models.

  7. Channeling effect in polycrystalline deuterium-saturated CVD diamond target bombarded by deuterium ion beam

    NASA Astrophysics Data System (ADS)

    Bagulya, A. V.; Dalkarov, O. D.; Negodaev, M. A.; Rusetskii, A. S.; Chubenko, A. P.; Ralchenko, V. G.; Bolshakov, A. P.

    2015-07-01

    At the ion accelerator HELIS at LPI, the neutron yield is investigated in DD reactions within a strongly textured polycrystalline deuterium-saturated CVD diamond under irradiation by a deuterium ion beam with the energy of less than 30 keV. The measurements of the neutron flux in the beam direction are performed using a multichannel detector based on 3He counters, in dependence on the target angle, β, with respect to the beam axis. A significant anisotropy in the neutron yield is observed. At β = 0° the yield is higher by a factor of 3 as compared to that at β = ±45°. The possible reasons for the anisotropy, including ion channeling, are discussed.

  8. Release of deuterium from irradiation damage in Fe-9Cr-2W ferritic alloy irradiated with deuterium ions

    NASA Astrophysics Data System (ADS)

    Ono, K.; Miyamoto, M.; Kudo, F.

    2014-09-01

    The release profile of deuterium from an Fe-9Cr-2W ferritic alloy irradiated with low-energy deuterium ions was studied by thermal desorption spectroscopy (TDS) and in situ transmission electron microscopy (TEM). It was found that one sharp TDS peak appeared at a temperature around 410 K depending on the heating rate that ranged from 1.5 to 20 K/min. The TDS peak height increased with increasing fluence from 2 × 1019 to 2 × 1021 D+/m2 with no shift of the peak temperature. A close correlation between these TDS peaks and the disappearance of dislocation loops formed by the irradiation was observed. The effects of tiny bubbles on TDS were small. These results suggest that most of the deuterium was trapped by dislocation loops, which affected the thermal stability of dislocation loops in the alloy. The dependence of TDS peak temperature on the heating rate yielded an activation energy of 0.63 ± 0.02 eV for deuterium de-trapping from dislocation loops. The retention properties of the total amount of deuterium exhibited a tendency of saturation at values on the order of 1020 D+/m2, which corresponded to a saturation tendency of the loop density.

  9. Diffusion, trapping, and isotope exchange of plasma implanted deuterium in ion beam damaged tungsten

    NASA Astrophysics Data System (ADS)

    Barton, Joseph Lincoln

    Tritium accumulation in nuclear fusion reactor materials is a major concern for practical and safe fusion energy. This work examines hydrogen isotope exchange as a tritium removal technique, analyzes the effects of neutron damage using high energy copper ion beams, and introduces a diffusion coefficient that is a function of the concentration of trapped atoms. Tungsten samples were irradiated with high energy (0.5 - 5 MeV) copper ions for controlled levels of damage - 10-3 to 10-1 displacements per atom (dpa) - at room temperature. Samples were then exposed to deuterium plasma at constant temperature (˜ 380 K) to a high fluence of 1024 ions/m2, where retention is at is maximized (i.e. saturated). By then subsequently exposing these samples to fractions of this fluence with hydrogen plasma, isotope exchange rates were observed. The resulting deuterium still trapped in the tungsten is then measured post mortem. Nuclear reaction analysis (NRA) gives the depth resolved deuterium retention profile with the 3He(D,p) 4He reaction, and thermal desorption spectroscopy (TDS) gives the total amount of deuterium trapped in the tungsten by heating a sample in vacuum up to 1200 K and measuring the evaporated gas molecules with a residual gas analyzer. Isotope exchange data show that hydrogen atoms can displace trapped deuterium atoms efficiently only up to the first few microns, but does not affect the atoms trapped at greater depths. In ion damaged tungsten, measurements showed a significant increase in retention in the damage region proportional to dpa 0.66, which results in a significant spike in total retention, and isotope exchange in damaged samples is still ineffective at depths greater than a few microns. Thus, isotope exchange is not an affective tritium removal technique; however, these experiments have shown that trapping in material defects greatly affects diffusion. These experiments lead to a simplified diffusion model with defect densities as the only free

  10. [Consideration of the deuterium-free water supply to an expedition to Mars].

    PubMed

    Siniak, Iu E; Turusov, V S; Grigor'ev, A I; Zaridze, D G; Gaĭdadymov, V B; Gus'kova, E I; Antoshina, E E; Gor'kova, T G; Trukhanova, L S

    2003-01-01

    Interplanetary missions, including to Mars, will put crews into severe radiation conditions. Search for methods of reducing the risk of radiation-induced cancer is of the top priority in preparation for the mission to Mars. One of the options is designing life support systems that will generate water with low content of the stable hydrogen isotope (deuterium) to be consumed by crewmembers. Preliminary investigations have shown that a decrease of the deuterium fraction by 65% does impart to water certain anti-cancer properties. Therefore, drinking deuterium-free water has the potential to reduce the risk of cancer consequent to the extreme radiation exposure of the Martian crew. PMID:14959623

  11. Detection of atomic deuterium in the upper atmosphere of Mars

    NASA Technical Reports Server (NTRS)

    Krasnopolsky, V. A.; Mumma, M. J.; Gladstone, G. R.

    1998-01-01

    High-resolution spectroscopy of Mars' atmosphere with the Hubble Space Telescope revealed the deuterium Lyman alpha line at an intensity of 23 +/- 6 rayleighs. This measured intensity corresponds to HD/H2 = 1.5 +/- 0.6 x 10(-4), which is smaller by a factor of 11 than HDO/H2O. This indicates that fractionation of HD/H2 relative to that of HDO/H2O is not kinetically controlled by the rates of formation and destruction of H2 and HD but is thermodynamically controlled by the isotope exchange HD + H2O left and right arrow HDO + H2. Molecular hydrogen is strongly depleted in deuterium relative to water on Mars because of the very long lifetime of H2 (1200 years). The derived isotope fractionation corresponds to an estimate of a planetwide reservoir of water ice about 5 meters thick that is exchangeable with the atmosphere.

  12. Detection of atomic deuterium in the upper atmosphere of Mars.

    PubMed

    Krasnopolsky, V A; Mumma, M J; Gladstone, G R

    1998-06-01

    High-resolution spectroscopy of Mars' atmosphere with the Hubble Space Telescope revealed the deuterium Lyman alpha line at an intensity of 23 +/- 6 rayleighs. This measured intensity corresponds to HD/H2 = 1.5 +/- 0.6 x 10(-4), which is smaller by a factor of 11 than HDO/H2O. This indicates that fractionation of HD/H2 relative to that of HDO/H2O is not kinetically controlled by the rates of formation and destruction of H2 and HD but is thermodynamically controlled by the isotope exchange HD + H2O left and right arrow HDO + H2. Molecular hydrogen is strongly depleted in deuterium relative to water on Mars because of the very long lifetime of H2 (1200 years). The derived isotope fractionation corresponds to an estimate of a planetwide reservoir of water ice about 5 meters thick that is exchangeable with the atmosphere. PMID:9616115

  13. Power-law dependence of the melting temperature of ubiquitin on the volume fraction of macromolecular crowders

    NASA Astrophysics Data System (ADS)

    Waegele, Matthias M.; Gai, Feng

    2011-03-01

    The dependence of the melting temperature increase (ΔTm) of the protein ubiquitin on the volume fraction (φ) of several commonly used macromolecular crowding agents (dextran 6, 40, and 70 and ficoll 70) was quantitatively examined and compared to a recently developed theoretical crowding model, i.e., ΔTm ˜ (Rg/Rc)αφα/3. We found that in the current case this model correctly predicts the power-law dependence of ΔTm on φ but significantly overestimates the role of the size (i.e., Rc) of the crowding agent. In addition, we found that for ubiquitin the exponent α is in the range of 4.1-6.5, suggesting that the relation of α = 3/(3ν - 1) is a better choice for estimating α based on the Flory coefficient (ν) of the polypeptide chain. Taken together these findings highlight the importance of improving our knowledge and theoretical treatment of the microcompartmentalization of the commonly used model crowding agents.

  14. Nucleon structure at large x: nuclear effects in deuterium

    SciTech Connect

    Wally Melnitchouk

    2010-07-01

    I review quark momentum distributions in the nucleon at large momentum fractions x. Particular attention is paid to the impact of nuclear effects in deuterium on the d/u quark distribution ratio as x -> 1. A new global study of parton distributions, using less restrictive kinematic cuts in Q^2 and W^2, finds strong suppression of the d quark distribution once nuclear corrections are accounted for.

  15. Spectral irradiance standard for the ultraviolet - The deuterium lamp

    NASA Technical Reports Server (NTRS)

    Saunders, R. D.; Ott, W. R.; Bridges, J. M.

    1978-01-01

    A set of deuterium lamps is calibrated as spectral irradiance standards in the 200-350-nm spectral region utilizing both a high accuracy tungsten spectral irradiance standard and a newly developed argon mini-arc spectral radiance standard. The method which enables a transfer from a spectral radiance to a spectral irradiance standard is described. The following characteristics of the deuterium lamp irradiance standard are determined: sensitivity to alignment; dependence on input power and solid angle; reproducibility; and stability. The absolute spectral radiance is also measured in the 167-330-nm region. Based upon these measurements, values of the spectral irradiance below 200 nm are obtained through extrapolation.

  16. Hydrogen and deuterium diffusion in vanadium-titanium alloys

    SciTech Connect

    Peterson, D.T.; Herro, H.M.

    1987-02-01

    Hydrogen and deuterium diffusion coefficients were measured in vanadium-titanium alloys, containing up to 30 at. pct Ti, by Boltzmann-Matano techniques. Hydrogen and deutrium diffusivity decreased rapidly with titanium concentration. The diffusion coefficients showed an Arrhenius temperature dependence in each alloy between 230 and 473 K with activation energies that increased with titanium concentration. The diffusion coefficient decreased linearly with hydrogen concentration in all alloys. The terminal solid solubilities increased markedly with titanium concentration with deuterium showing a larger terminal solid solubility than hydrogen below ten percent titanium. The diffusion results do not fit a localized deep trapping of hydrogen by the titanium atoms.

  17. Transport of Recycled Deuterium to the Plasma Core in TFTR

    SciTech Connect

    Bell, M.G.; Budny, R.V.; Jassby, D.L.; Park, H.; Skinner, C.H.; et al

    1997-10-01

    We report a study of the fueling of the plasma core by recycling in the Tokamak Fusion Test Reactor (TFTR) [Phys. Plasmas 2, 2176 (1995)]. We have analyzed discharges fueled by deuterium recycled from the limiter and tritium-only neutral beam injection. In these plasmas, the DT neutron rate provides a measure of the deuterium influx into the core plasma. We find a reduced influx with plasmas using lithium pellet conditioning and with plasmas of reduced major (and minor) radius. Modeling with the DEGAS neutrals code shows that the dependence on radius can be related to the penetration of neutrals through the scrape-off layer.

  18. Transport of recycled deuterium to the plasma core in TFTR

    SciTech Connect

    Skinner, C.H.; Bell, M.G.; Budny, R.V.; Jassby, D.L.; Park, H.; Ramsey, A.T.; Stotler, D.P.; Strachan, J.D.

    1997-10-01

    The authors report a study of the fueling of the plasma core by recycling in the Tokamak Fusion Test Reactor (TFTR). They have analyzed discharges fueled by deuterium recycled from the limiter and tritium-only neutral beam injection. In these plasmas, the DT neutron rate provides a measure of the deuterium influx into the core plasma. They find a reduced influx with plasmas using lithium pellet conditioning and with plasmas of reduced major (and minor) radius. Modeling with the DEGAS neutrals code shows that the dependence on radius can be related to the penetration of neutrals through the scrape-off layer.

  19. The CALYMHA survey: Lyα escape fraction and its dependence on galaxy properties at z = 2.23

    NASA Astrophysics Data System (ADS)

    Matthee, Jorryt; Sobral, David; Oteo, Iván; Best, Philip; Smail, Ian; Röttgering, Huub; Paulino-Afonso, Ana

    2016-05-01

    We present the first results from our CAlibrating LYMan α with Hα (CALYMHA) pilot survey at the Isaac Newton Telescope. We measure Lyα emission for 488 Hα selected galaxies at z = 2.23 from High-z Emission Line Survey in the COSMOS and UDS fields with a specially designed narrow-band filter (λc = 3918 Å, Δλ = 52 Å). We find 17 dual Hα-Lyα emitters [fLyα > 5 × 10-17 erg s-1 cm-2, of which five are X-ray active galactic nuclei (AGN)]. For star-forming galaxies, we find a range of Lyα escape fractions (fesc, measured with 3 arcsec apertures) from 2 to 30 per cent. These galaxies have masses from 3 × 108 M⊙ to 1011 M⊙ and dust attenuations E(B - V) = 0-0.5. Using stacking, we measure a median escape fraction of 1.6 ± 0.5 per cent (4.0 ± 1.0 per cent without correcting Hα for dust), but show that this depends on galaxy properties. The stacked fesc tends to decrease with increasing star formation rate and dust attenuation. However, at the highest masses and dust attenuations, we detect individual galaxies with fesc much higher than the typical values from stacking, indicating significant scatter in the values of fesc. Relations between fesc and UV slope are bimodal, with high fesc for either the bluest or reddest galaxies. We speculate that this bimodality and large scatter in the values of fesc is due to additional physical mechanisms such as outflows facilitating fesc for dusty/massive systems. Lyα is significantly more extended than Hα and the UV. fesc continues to increase up to at least 20 kpc (3σ, 40 kpc [2σ]) for typical star-forming galaxies and thus the aperture is the most important predictor of fesc.

  20. Branching fraction and time-dependent CP asymmetry in neutral B decays to psi and a neutral pion

    NASA Astrophysics Data System (ADS)

    Soha, Aron Lucas

    The invariance of physical laws under the combination of exchange of particles with antiparticles (charge conjugation, C) and reversal of coordinates (parity, P) is called CP symmetry. The violation of CP symmetry was first discovered in 1964 in the neutral kaon system, and is in general one of the great puzzles of particle physics. The recent observation of CP violation in the B meson system has been a simultaneous success for model predictions and experiment. The opportunity now exists to probe details of the underlying mechanisms. This thesis presents measurements of the branching fraction and time-dependent CP-violating asymmetry in neutral B decays to J/ y pi0. The decay amplitude for this channel features both tree and penguin diagram contributions, the interference of which can yield a result for the asymmetry differing from that found in the "golden mode" B0 → J/ yK0S . Using the measured branching fraction and CP asymmetry, constraints are placed on the ratio of penguin to tree amplitudes in B0 → J/ y pi0. In addition, the impact on the CP asymmetry measurement in B0 → J/ yK0S is discussed. The results are presented for e+ e- annihilation data collected with the BABAR detector on the Upsilon(4S) resonance at the PEP-II asymmetric-energy B Factory at SLAC. The measurement of the branching fraction, based on about 23 million BB¯ pairs collected between October 1999 and October 2000, yields BF(B0 → J/ y pi0) = (2.0 +/- 0.6 (stat) +/- 0.2 (syst)) x 10-5. With about 88 million BB¯ pairs collected during the years 1999--2002, our results for the coefficients of the cosine and sine terms of the CP asymmetry are CJ/ y pi0 = 0.38 +/- 0.41 (stat) +/- 0.09 (syst) and SJ/ y pi0 = 0.05 +/- 0.49 (stat) +/- 0.16 (syst).

  1. Study of ion-irradiated tungsten in deuterium plasma

    NASA Astrophysics Data System (ADS)

    Khripunov, B. I.; Gureev, V. M.; Koidan, V. S.; Kornienko, S. N.; Latushkin, S. T.; Petrov, V. B.; Ryazanov, A. I.; Semenov, E. V.; Stolyarova, V. G.; Danelyan, L. S.; Kulikauskas, V. S.; Zatekin, V. V.; Unezhev, V. N.

    2013-07-01

    Experimental study aimed at investigation of neutron induced damage influence on fusion reactor plasma facing materials is reported. Displacement damage was produced in tungsten by high-energy helium and carbon ions at 3-10 MeV. The reached level of displacement damage ranged from several dpa to 600 dpa. The properties of the irradiated tungsten were studied in steady-state deuterium plasma on the LENTA linear divertor simulator. Plasma exposures were made at 250 eV of ion energy to fluence 1021-1022 ion/сm2. Erosion dynamics of the damaged layer and deuterium retention were observed. Surface microstructure modifications and important damage of the 5 μm layer shown. Deuterium retention in helium-damaged tungsten (ERD) showed its complex behavior (increase or decrease) depending on implanted helium quantity and the structure of the surface layer.

  2. Deuterium chemistry in protoplanetary disks

    NASA Astrophysics Data System (ADS)

    Albertsson, T.; Semenov, D.; Henning, T.

    2011-05-01

    We have generated a extensive chemical network that includes reactions with multi-deuterated species, in which the most recent information deuterium chemistry is implemented. By implementing this chemical network with our sophisticated model, we study in detail the chemical evolution of protoplanetary disks, and compare our results with observations.

  3. Solid deuterium centrifuge pellet injector

    SciTech Connect

    Foster, C.A.

    1982-01-01

    Pellet injectors are needed to fuel long pulse tokamak plasmas and other magnetic confinement devices. For this purpose, an apparatus has been developed that forms 1.3-mm-diam pellets of frozen deuterium at a rate of 40 pellets per second and accelerates them to a speed of 1 km/s. Pellets are formed by extruding a billet of solidified deuterium through a 1.3-mm-diam nozzle at a speed of 5 cm/s. The extruding deuterium is chopped with a razor knife, forming 1.3-mm right circular cylinders of solid deuterium. The pellets are accelerated by synchronously injecting them into a high speed rotating arbor containing a guide track, which carries them from a point near the center of rotation to the periphery. The pellets leave the wheel after 150/sup 0/ of rotation at double the tip speed. The centrifuge is formed in the shape of a centrifugal catenary and is constructed of high strength KEVLAR/epoxy composite. This arbon has been spin-tested to a tip speed of 1 km/s.

  4. Solid deuterium centrifuge pellet injector

    SciTech Connect

    Foster, C.A.

    1983-04-01

    Pellet injectors are needed to fuel long pulse tokamak plasmas and other magnetic confinement devices. For this purpose, an apparatus has been developed that forms 1.3-mm-diam pellets of frozen deuterium at a rate of 40 pellets per second and accelerates them to a speed of 1 km/s. Pellets are formed by extruding a billet of solidified deuterium through a 1.3-mm-diam nozzle at a speed of 5 cm/s. The extruding deuterium is chopped with a razor knife, forming 1.3-mm right circular cylinders of solid deuterium. The pellets are accelerated by synchronously injecting them into a high speed rotating arbor containing a guide track, which carries them from a point near the center of rotation to the periphery. The pellets leave the wheel after 150/sup 0/ of rotation at double the tip speed. The centrifuge is formed in the shape of a centrifugal catenary and is constructed of high strength Kevlar/epoxy composite. This arbor has been spin-tested to a tip speed of 1 km/s.

  5. Deuterium pellet injector gun design

    SciTech Connect

    Lunsford, R.V.; Wysor, R.B.; Bryan, W.E.; Shipley, W.D.; Combs, S.K.; Foust, C.R.; Milora, S.L.; Fisher, P.W.

    1985-01-01

    The Deuterium Pellet Injector (DPI), an eight-pellet pneumatic injector, is being designed and fabricated for the Tokamak Fusion Test Reactor (TFTR). It will accelerate eight pellets, 4 by 4 mm maximum, to greater than 1500 m/s. It utilizes a unique pellet-forming mechanism, a cooled pellet storage wheel, and improved propellant gas scavenging.

  6. Exposure of Equal-Channel Angular Extruded Tungsten to Deuterium Plasma

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Xu, Yuping; Zhou, Haishan; Zhao, Sixiang; Li, Bo; Lyu, Guanghong; Yuan, Yue; Hao, Ting; Luo, Guangnan

    2015-07-01

    Surface morphology and deuterium retention in ultrafine-grained tungsten fabricated by equal-channel angular pressing (ECAP) have been examined after exposure to a low energy, high-flux deuterium (D) plasma at fluences of 3×1024 D/m2 and 1×1025 D/m2 in a temperature range of 100°C-150°C. The methods used were scanning electron microscopy (SEM) and thermal desorption spectroscopy (TDS). Sparse and small blisters (∼0.1 μm) were observed by SEM after D plasma irradiation on every irradiated surface; yet they did not exhibit significant structure or plasma fluence dependence. Larger blisters or protrusions appeared after subsequent TDS heating up to 1000°C. The TDS results showed a single D desorption peak at ∼220°C for all samples and the D retention increased with increasing numbers of extrusion passes, i.e., the decrease of grain sizes. The increased D retention in this low temperature range should be attributed to the faster diffusion of D along the larger volume fraction of grain boundaries introduced by ECAP. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB105001, 2013GB105002, 2015GB109001), National Natural Science Foundation of China (Nos. 11305213, 11405201), Technological Development Grant of Hefei Science Center of CAS (No. 2014TDG-HSC003), and China National Funds for Distinguished Young Scientists (No. 51325103)

  7. Thermal desorption of deuterium implanted into beryllium

    SciTech Connect

    Markin, A.V.; Chernikov, V.N.; Zakharov, A.P.

    1995-09-01

    By means of TDS measurements it is shown that the desorption of deuterium from Be implanted with 5 keV D ions to fluences, {Phi}, from 1x10{sup 20} D/m{sup 2} to 1x10{sup 21} D/m{sup 2} proceeds in one high temperature stage B, while at {Phi} {ge} 1.2x10{sup 21}D/m{sup 2} one more stage A is added. The desorption maximum A is narrow and consists of two peaks A{sub 1} and A{sub 2} at about 460 K and 490 K, respectively. Peak A{sub 1} is attributed to the desorption of deuterium from the walls of opened channels formed under D ion implantation. Peak {sub A}2 is a consequence of the opening of a part of closed bubbles/channels to the outer surface. The position of maximum B shifts noticeably and nonsteadily on the fluence in a range from 850 to 1050 K. The origin of this maximum is the liberation of D atoms bound at vacancy complexes discussed previously by Wampler. The dependence of Tm(B) on the fluence is governed by the interaction of freely migrating D atoms with partly opened or fully closed gas cavity arrangements which are created under temperature ramping, but differently in specimens implanted with D ions to different fluences.

  8. The diffusion of muonic deuterium atoms in deuterium gas

    SciTech Connect

    Kraiman, J.B.

    1989-01-01

    Negative muons were brought to rest in a target array consisting of 30-50 parallel plastic foils coated with Au which were separated by a few mm. The interstitial volumes between the foils were filled with deuterium gas at pressures from 0.094 bar to 1.52 bar. Muons which stopped in the deuterium formed {mu}d atoms, which subsequently diffused through the gas until either the muon decayed or the {mu}d atom struck a foil surface. For {mu}d atoms impinging upon the Au layer, the muon would transfer to an Au atom, resulting in the formation of a {mu}Au atom in a highly excited state. De-excitation to the 1S ground state resulted in emission of characteristic muonic Au x rays, and after the muon was absorbed by the Au nucleus, the emission of Pt {gamma} rays. These transfer photons were detected by one of four germanium x-ray detectors adjacent to the target vessel. Analysis of the time distributions formed by collecting delayed transfer events for several sets of experimental conditions yielded information on the diffusion process of {mu}d atoms in deuterium gas.

  9. Laser spectroscopy of muonic deuterium

    NASA Astrophysics Data System (ADS)

    Pohl, Randolf; Nez, François; Fernandes, Luis M. P.; Amaro, Fernando D.; Biraben, François; Cardoso, João M. R.; Covita, Daniel S.; Dax, Andreas; Dhawan, Satish; Diepold, Marc; Giesen, Adolf; Gouvea, Andrea L.; Graf, Thomas; Hänsch, Theodor W.; Indelicato, Paul; Julien, Lucile; Knowles, Paul; Kottmann, Franz; Le Bigot, Eric-Olivier; Liu, Yi-Wei; Lopes, José A. M.; Ludhova, Livia; Monteiro, Cristina M. B.; Mulhauser, Françoise; Nebel, Tobias; Rabinowitz, Paul; dos Santos, Joaquim M. F.; Schaller, Lukas A.; Schuhmann, Karsten; Schwob, Catherine; Taqqu, David; Veloso, João F. C. A.; Antognini, Aldo

    2016-08-01

    The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important benchmarks for understanding the nuclear forces and structure. Muonic deuterium μd is the exotic atom formed by a deuteron and a negative muon μ–. We measured three 2S-2P transitions in μd and obtain rd = 2.12562(78) fm, which is 2.7 times more accurate but 7.5σ smaller than the CODATA-2010 value rd = 2.1424(21) fm. The μd value is also 3.5σ smaller than the rd value from electronic deuterium spectroscopy. The smaller rd, when combined with the electronic isotope shift, yields a “small” proton radius rp, similar to the one from muonic hydrogen, amplifying the proton radius puzzle.

  10. Laser spectroscopy of muonic deuterium.

    PubMed

    Pohl, Randolf; Nez, François; Fernandes, Luis M P; Amaro, Fernando D; Biraben, François; Cardoso, João M R; Covita, Daniel S; Dax, Andreas; Dhawan, Satish; Diepold, Marc; Giesen, Adolf; Gouvea, Andrea L; Graf, Thomas; Hänsch, Theodor W; Indelicato, Paul; Julien, Lucile; Knowles, Paul; Kottmann, Franz; Le Bigot, Eric-Olivier; Liu, Yi-Wei; Lopes, José A M; Ludhova, Livia; Monteiro, Cristina M B; Mulhauser, Françoise; Nebel, Tobias; Rabinowitz, Paul; dos Santos, Joaquim M F; Schaller, Lukas A; Schuhmann, Karsten; Schwob, Catherine; Taqqu, David; Veloso, João F C A; Antognini, Aldo

    2016-08-12

    The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important benchmarks for understanding the nuclear forces and structure. Muonic deuterium μd is the exotic atom formed by a deuteron and a negative muon μ(-). We measured three 2S-2P transitions in μd and obtain r(d) = 2.12562(78) fm, which is 2.7 times more accurate but 7.5σ smaller than the CODATA-2010 value r(d) = 2.1424(21) fm. The μd value is also 3.5σ smaller than the r(d) value from electronic deuterium spectroscopy. The smaller r(d), when combined with the electronic isotope shift, yields a "small" proton radius r(p), similar to the one from muonic hydrogen, amplifying the proton radius puzzle. PMID:27516595

  11. Community N and O isotope fractionation by sulfide-dependent denitrification and anammox in a stratified lacustrine water column

    NASA Astrophysics Data System (ADS)

    Wenk, Christine B.; Zopfi, Jakob; Blees, Jan; Veronesi, Mauro; Niemann, Helge; Lehmann, Moritz F.

    2014-01-01

    We investigated the community nitrogen (N) and oxygen (O) isotope effects of fixed N loss in the northern basin of Lake Lugano, where sulfide-dependent denitrification and anammox are the main drivers of suboxic N2 production. A decrease in nitrate (NO3-) concentration toward the redox transition zone (RTZ) at mid-water depth was paralleled by an increase in δ15N and δ18O from approximately 5‰ to >20‰ and from 0‰ to >10‰, respectively. Ammonium (NH4+) concentrations were highest in the near-bottom water and decreased toward the RTZ concomitant with an increase in δ15N-NH4+ from ∼7‰ to >15‰. A diffusion-reaction model yielded N and O isotope enrichment factors that are significantly smaller than isotope effects reported previously for microbial NO3- reduction and NH4+ oxidation (15εNO3 ≈ 10‰, 18εNO3 ≈ 7‰, and 15εNH4 ≈ 10-12‰). For the Lake Lugano north basin, we constrain the apparent under-expression of the N isotope effects to: (1) environmental conditions (e.g., substrate limitation, low cell specific N transformation rates), or (2) low process-specific (chemolithotrophic denitrification and anammox) isotope fractionation. Our results have confirmed the robust nature of the co-linearity between N and O isotope enrichment during microbial denitrification beyond its organotrophic mode. However, the ratio of 18O to 15N enrichment (18εNO3:15εNO3) associated with NO3- reduction in the RTZ was ∼0.89, which is lower than observed in marine environments and in most culture experiments. We propose that chemolithotrophic NO3- reduction in the Lake Lugano north basin was partly catalyzed by the periplasmic dissimilatory nitrate reductase (Nap) (rather than the membrane-bound dissimilatory Nar), which is known to express comparably low 18εNO3:15εNO3 ratios in the ambient NO3- pool. However, NO2- re-oxidation, e.g., during anammox or microaerobic nitrification, could have contributed to the lowered 18O to 15N enrichment ratios. Although

  12. Conditional dependence of evaporative fraction on surface and root-zone soil moisture and its application to soil moisture retrieval

    NASA Astrophysics Data System (ADS)

    Ryu, D.; Akuraju, V.

    2013-12-01

    Thermal infrared (TIR) or evapotranspiration (ET) estimates from space have been gaining growing attention as an input to retrieve root-zone soil moisture. The rationale behind the approach is that i) there exists a strong causal link between the evapotranspiration and the vegetation canopy temperature and ii) under water-limited conditions soil water available for transpiration controls the evaporative fraction (EF) or the actual evapotranspiration (AET) to potential evapotranspiration (PET) ratio of vegetated surfaces. In this work, we examine the relationship between EF and surface to root-zone soil moisture content collected from two study sites (wheat and pasture fields) at the Dookie research farm site in Victoria, Australia. EF estimated from the eddy covariance system is compared with soil moisture content under various ranges of soil depths (5 depths from surface to 120 cm), net radiation, soil wetness and biomass. In both wheat and pasture fields, EF is highly correlated with surface (0-8 cm) soil moisture when the soil surface is bare-to-lightly vegetated, but the correlation decreases as vegetation grows or as the net radiation decreases. On the other hand, EF shows strong correlation with root-zone soil moisture during the growing seasons of the fields. Under similar ranges of soil moisture and net radiation, EF can have different ranges depending on the vegetation height and density. These results indicate the importance of biophysical parameters and processes in estimating surface and root-zone soil moisture contents using surface energy flux. We propose an exponential and a spherical model to fit EF versus soil moisture and show how their uncertainty changes with biophysical parameters.

  13. Depletion of GSH in human blood plasma and cytosolic fraction during cadmium toxicity is temperature and pH dependent.

    PubMed

    Ullah, Hashmat; Khan, Muhammad Farid; Jan, Syed Umer; Hashmat, Farwa

    2016-01-01

    Toxicities of heavy metals is a burning issue and a topic of interest among the toxicologists throughout the world. Metals are always in use of man since long but in recent years the use of cadmium has increased in the form of various cadmium compounds such as cadmium compounds as stabilizers in plastic pipe industries and in the preparations of different alloys etc. Cadmium is even used in phosphate fertilizers and thus comes directly or indirectly in contact with human eatables like crops, vegetables and fruits. Once it is absorbed it affects almost all the organs and systems of human body especially blood components and kidneys. Always the chemical reactions of different chemicals are dependent on some influential factors, among these factors the effect of pH and temperature of the media in which these chemicals interact with each other are very much important. Keeping in view this fact we have evaluated the effect of cadmium nitrate tetra hydrate on GSH of human plasma and cytosolic fraction. Estimation of thiol was done by Ellman's modified method and was found that the interaction of cadmium nitrate tetra hydrate and GSH of these blood components was more at a pH and temperature, which were near to physiological pH and temperature of human body. This fact was proved as the estimated thiol concentration left after the interaction of cadmium nitrate tetra hydrate and thiol of these blood components was minimum at pH and temperature near to human blood pH and temperature. We concluded that the possible reason for depletion of GSH of these blood components was conversion of GSH into Cd(SG) (2) and/or GSSG formation. PMID:26826820

  14. Geographic origin determination of heroin and cocaine using site-specific isotopic ratio deuterium NMR

    PubMed

    Hays; Remaud; Jamin; Martin

    2000-05-01

    SNIF-NMR (Site-specific natural isotopic fractionation measured by deuterium NMR) was employed on 36 heroin samples from seven different known origins, and two cocaine samples from two different known origins. Heroin has two "synthetic" deuterium labeled sites (the two acetyls from acetic anhydride, each representing three equivalent nuclei) and 15 "natural" deuterium labeled sites (originating from the morphine produced in the opium plant). The "natural" sites have the potential for determining geographic location of the original opium plant, while the "synthetic" sites could assist in giving information about the commercial source of acetic anhydride used to convert morphine to heroin. Cocaine has 15 "natural" deuterium labeled sites. This study shows that SNIF-NMR has some use in determining the geographic origin of heroin and also has good potential for determining the geographical origin of cocaine. PMID:10855958

  15. Deuterium gas-puff Z-pinch implosions on the Z accelerator

    SciTech Connect

    Coverdale, C. A.; Deeney, C.; Ruiz, C. L.; Velikovich, A. L.; Davis, J.; Clark, R. W.; Chong, Y. K.; Apruzese, J. P.; Chittenden, J.; Chantrenne, S.; Franklin, J.; LePell, P. D.; Cooper, G. W.; Nelson, A. J.; Levine, J.; Banister, J.

    2007-05-15

    Experiments on the Z accelerator with deuterium gas-puff implosions have produced up to 3.7x10{sup 13} ({+-}20%) neutrons at 2.34 MeV ({+-}0.10 MeV). Although the mechanism for generating these neutrons was not definitively identified, this neutron output is 100 times more than previously observed from neutron-producing experiments at Z. Dopant gases in the deuterium (argon and chlorine) were used to study implosion characteristics and stagnated plasma conditions through x-ray yield measurements and spectroscopy. Magnetohydrodynamic (MHD) calculations have suggested that the dopants improved the neutron output through better plasma compression, which has been studied in experiments increasing the dopant fraction. Scaling these experiments, and additional MHD calculations, suggest that {approx}5x10{sup 14} deuterium-deuterium (DD) neutrons could be generated at the 26-MA refurbished Z facility.

  16. Single crystal diamond detector measurements of deuterium-deuterium and deuterium-tritium neutrons in Joint European Torus fusion plasmas

    SciTech Connect

    Cazzaniga, C. Gorini, G.; Nocente, M.; Sundén, E. Andersson; Binda, F.; Ericsson, G.; Croci, G.; Grosso, G.; Cippo, E. Perelli; Tardocchi, M.; Giacomelli, L.; Rebai, M.; Griesmayer, E.; Kaveney, G.; Syme, B.; Collaboration: JET-EFDA Contributors

    2014-04-15

    First simultaneous measurements of deuterium-deuterium (DD) and deuterium-tritium neutrons from deuterium plasmas using a Single crystal Diamond Detector are presented in this paper. The measurements were performed at JET with a dedicated electronic chain that combined high count rate capabilities and high energy resolution. The deposited energy spectrum from DD neutrons was successfully reproduced by means of Monte Carlo calculations of the detector response function and simulations of neutron emission from the plasma, including background contributions. The reported results are of relevance for the development of compact neutron detectors with spectroscopy capabilities for installation in camera systems of present and future high power fusion experiments.

  17. Single crystal diamond detector measurements of deuterium-deuterium and deuterium-tritium neutrons in Joint European Torus fusion plasmas

    NASA Astrophysics Data System (ADS)

    Cazzaniga, C.; Sundén, E. Andersson; Binda, F.; Croci, G.; Ericsson, G.; Giacomelli, L.; Gorini, G.; Griesmayer, E.; Grosso, G.; Kaveney, G.; Nocente, M.; Cippo, E. Perelli; Rebai, M.; Syme, B.; Tardocchi, M.

    2014-04-01

    First simultaneous measurements of deuterium-deuterium (DD) and deuterium-tritium neutrons from deuterium plasmas using a Single crystal Diamond Detector are presented in this paper. The measurements were performed at JET with a dedicated electronic chain that combined high count rate capabilities and high energy resolution. The deposited energy spectrum from DD neutrons was successfully reproduced by means of Monte Carlo calculations of the detector response function and simulations of neutron emission from the plasma, including background contributions. The reported results are of relevance for the development of compact neutron detectors with spectroscopy capabilities for installation in camera systems of present and future high power fusion experiments.

  18. Deuterium Abundance in Consciousness and Current Cosmology

    NASA Astrophysics Data System (ADS)

    Rauscher, Elizabeth A.

    We utilize the deuterium-hydrogen abundances and their role in setting limits on the mass and other conditions of cosmogenesis and cosmological evolution. We calculate the dependence of a set of physical variables such as density, temperature, energy mass, entropy and other physical variable parameters through the evolution of the universe under the Schwarzschild conditions as a function from early to present time. Reconciliation with the 3°K and missing mass is made. We first examine the Schwarzschild condition; second, the geometrical constraints of a multidimensional Cartesian space on closed cosmologies, and third we will consider the cosmogenesis and evolution of the universe in a multidimensional Cartesian space, obeying the Schwarzschild condition. Implications of this model for matter creation are made. We also examine experimental evidence for closed versus open cosmologies; x-ray detection of the "missing mass" density. Also the interstellar deuterium abundance, along with the value of the Hubble constant set a general criterion on the value of the curvature constant, k. Once the value of the Hubble constant, H is determined, the deuterium abundance sets stringent restrictions on the value of the curvature constant k by an detailed discussion is presented. The experimental evidences for the determination of H and the primary set of coupled equations to determine D abundance is given. 'The value of k for an open, closed, or flat universe will be discussed in terms of the D abundance which will affect the interpretation of the Schwarzschild, black hole universe. We determine cosmology solutions to Einstein's field obeying the Schwarzschild solutions condition. With this model, we can form a reconciliation of the black hole, from galactic to cosmological scale. Continuous creation occurs at the dynamic blackhole plasma field. We term this new model the multiple big bang or "little whimper model". We utilize the deuteriumhydrogen abundances and their role in

  19. Mass-dependent sulfur isotope fractionation during reoxidative sulfur cycling: A case study from Mangrove Lake, Bermuda

    NASA Astrophysics Data System (ADS)

    Pellerin, André; Bui, Thi Hao; Rough, Mikaella; Mucci, Alfonso; Canfield, Donald E.; Wing, Boswell A.

    2015-01-01

    The multiple sulfur isotope composition of porewater sulfate from the anoxic marine sapropel of Mangrove Lake, Bermuda was measured in order to establish how multiple sulfur isotopes are fractionated during reoxidative sulfur cycling. The porewater-sulfate δ34S and Δ33S dataset exhibits the distinct isotopic signatures of microbial sulfate reduction and sulfur reoxidation. We reproduced the measurements with a simple diagenetic model that yielded fractionation factors for net sulfate removal of between -29.2‰ and -32.5‰. A new approach to isotopic modeling of the sulfate profiles, informed by the chemistry of sulfur intermediate compounds in Mangrove Lake, reveals that sulfate reduction produces a relatively small intrinsic fractionation and that an active reoxidative sulfur cycle increases the fractionation of the measured values. Based on the model results, the reoxidative cycle of Mangrove Lake appears to include sulfide oxidation to elemental sulfur followed by the disproportionation of the elemental sulfur to sulfate and sulfide. This model also indicates that the reoxidative sulfur cycle of Mangrove Lake turns over from 50 to 80% of the sulfide produced by microbial sulfate reduction. The Mangrove Lake case study shows how sulfur isotope fractionations can be separated into three different "domains" in Δ33S-δ34S space based on their ability to resolve reductive and reoxidative sulfur transformations. The first domain that differentiates reductive and reoxidative sulfur cycling is well illustrated by previous studies and requires 34S-32S fractionations more negative than ≈-70‰, beyond the fractionation limit of microbial sulfate reduction at earth surface temperatures. The second domain that distinguishes reductive and reoxidative processes is between 34S-32S fractionations of -40‰ and 0‰, where the 33S-32S fractionations of sulfate reduction and reoxidation are significantly different. In the remaining domain (between 34S-32S fractionations

  20. Low deuterium content of Lake Vanda, Antarctica

    USGS Publications Warehouse

    Ragotzkie, R.A.; Friedman, I.

    1965-01-01

    Lake Vanda in Victoria Land, Antarctica, is permanently ice-covered and permanently stratified, with warm, salty water near the bottom. Deuterium analyses of lake water from several levels indicate that the lake has a low deuterium content, and that it is stratified with respect to this isotope. This low deuterium content supports the evidence from the lake's ionic content that the saline layer is not of marine origin, and it indicates that evaporation from the ice surface has taken place. The stratification of the lake with respect to deuterium suggests that the upper and lower layers of water were formed at different times from different sources of glacial melt water.

  1. Deuterium accelerator experiments for APT.

    SciTech Connect

    Causey, Rion A. (Sandia National Laboratories, Livermore, CA); Hertz, Kristin L. (Sandia National Laboratories, Livermore, CA); Cowgill, Donald F. (Sandia National Laboratories, Livermore, CA)

    2005-08-01

    Sandia National Laboratories in California initiated an experimental program to determine whether tritium retention in the tube walls and permeation through the tubes into the surrounding coolant water would be a problem for the Accelerator Production of Tritium (APT), and to find ways to mitigate the problem, if it existed. Significant holdup in the tube walls would limit the ability of APT to meet its production goals, and high levels of permeation would require a costly cleanup system for the cooling water. To simulate tritium implantation, a 200 keV accelerator was used to implant deuterium into Al 6061-T and SS3 16L samples at temperatures and particle fluxes appropriate for APT, for times varying between one week and five months. The implanted samples were characterized to determine the deuterium retention and Permeation. During the implantation, the D(d,p)T nuclear reaction was used to monitor the build-up of deuterium in the implant region of the samples. These experiments increased in sophistication, from mono-energetic deuteron implants to multi-energetic deuteron and proton implants, to more accurately reproduce the conditions expected in APT. Micron-thick copper, nickel, and anodized aluminum coatings were applied to the front surface of the samples (inside of the APT walls) in an attempt to lower retention and permeation. The reduction in both retention and permeation produced by the nickel coatings, and the ability to apply them to the inside of the APT tubes, indicate that both nickel-coated Al 6061-T6 and nickel-coated SS3 16L tubes would be effective for use in APT. The results of this work were submitted to the Accelerator Production of Tritium project in document number TPO-E29-Z-TNS-X-00050, APT-MP-01-17.

  2. Mass dependent fractionation of stable chromium isotopes in mare basalts: Implications for the formation and the differentiation of the Moon

    NASA Astrophysics Data System (ADS)

    Bonnand, Pierre; Parkinson, Ian J.; Anand, Mahesh

    2016-02-01

    We present the first stable chromium isotopic data from mare basalts in order to investigate the similarity between the Moon and the Earth's mantle. A double spike technique coupled with MC-ICP-MS measurements was used to analyse 19 mare basalts, comprising high-Ti, low-Ti and KREEP-rich varieties. Chromium isotope ratios (δ53Cr) for mare basalts are positively correlated with indices of magmatic differentiation such as Mg# and Cr concentration which suggests that Cr isotopes were fractionated during magmatic differentiation. Modelling of the results provides evidence that spinel and pyroxene are the main phases controlling the Cr isotopic composition during fractional crystallisation. The most evolved samples have the lightest isotopic compositions, complemented by cumulates that are isotopically heavy. Two hypotheses are proposed to explain this fractionation: (i) equilibrium fractionation where heavy isotopes are preferentially incorporated into the spinel lattice and (ii) a difference in isotopic composition between Cr2+ and Cr3+ in the melt. However, both processes require magmatic temperatures below 1200 °C for appreciable Cr3+ to be present at the low oxygen fugacities found in the Moon (IW -1 to -2 log units). There is no isotopic difference between the most primitive high-Ti, low-Ti and KREEP basalts, which suggest that the sources of these basalts were homogeneous in terms of stable Cr isotopes. The least differentiated sample in our sample set is the low-Ti basalt 12016, characterised by a Cr isotopic composition of -0.222 ± 0.025‰, which is within error of the current BSE value (-0.124 ± 0.101‰). The similarity between the mantles of the Moon and Earth is consistent with a terrestrial origin for a major fraction of the lunar Cr. This similarity also suggests that Cr isotopes were not fractionated by core formation on the Moon.

  3. Was Venus wet? Deuterium reconsidered

    NASA Technical Reports Server (NTRS)

    Grinspoon, David H.

    1987-01-01

    The ratio of deuterium to hydrogen on Venus has been accepted as proof of a wetter, more earth-like part on that planet. However, the present-day water abundance and the nonthermal hydrogen escape flux on Venus imply that hydrogen is in a steady state and that a hydrogen source, most likely cometary infall, is present. An alternative interpretation of the D/H ratio is offered, in which the measured value is consistent with a steady-state evolution over the age of the solar system. No past water excess is required to explain the isotopic data.

  4. Retention behavior in tungsten and molybdenum exposed to high fluences of deuterium ions in TPE

    SciTech Connect

    J.P. Sharpe; R.D. Kolasinski; M. Shimada; P. Calderoni; R.A. Causey

    2009-06-01

    The Tritium Plasma Experiment (TPE) has been used to investigate deuterium fuel retention behavior in tungsten and molybdenum– materials utilized for plasma-facing surfaces in some existing tokamak plasma devices and under consideration for future devices. Although several studies have been performed over the past several years on these metals, many issues remain unresolved, including for example blister formation mechanisms and correlation to surface conditions. In this study we expose several metal samples to deuterium ion fluences up to 1026 ions/m2 and measure retention behavior with thermal desportion spectroscopy. Fractional retention of up to 2.0×10-5 is found for W at 600 K, and Mo similarly retains deuterium at a fraction of 1.5×10-5 at 600 K. Blistering was found for W samples exposed at temperatures above 453 K, whereas blistering was not observed for Mo samples at any experiment temperature.

  5. Fundamental aspects of deuterium retention in tungsten at high flux plasma exposure

    SciTech Connect

    Ogorodnikova, O. V.

    2015-08-21

    An effect of enhanced trapping of deuterium in tungsten at high flux was discovered. It was shown analytically and confirmed experimentally that the deuterium trapping in a presence of high density of defects in tungsten (W) depends on the ion energy and ion flux. Newly developed analytical model explains experimentally observed discrepancy of deuterium trapping at radiation-induced defects in tungsten at different ion fluxes that significantly improves a prediction of hydrogen isotope accumulation in different plasma devices, including ITER and DEMO. The developed model can be used for many system of hydrogen in a metal in both normal and extreme environments (high fluxes, elevated temperatures, neutron irradiation, etc.). This new model allows, for the first time, to validate density function theory (DFT) predictions of multiple occupation of a defect with deuterium against experimental data that bridge the gap in length and time scale between DFT calculations and experiments. By comparing first-principle calculations based on DFT and semi-empirical “adsorption model,” it was proved that the mechanism of hydrogen isotope trapping in a vacancy cluster is similar to a chemisorption on a surface. Binding energies of deuterium with different types of defects in W were defined. Moreover, the surface barrier of deuterium to be chemisorbed on a clean W surface was found to be less than 1 eV and kinetics of deuterium release is limited by de-trapping from defects rather than to be limited by surface effects.

  6. Ion-induced deuterium retention in tungsten coatings on carbon substrate

    NASA Astrophysics Data System (ADS)

    Ogorodnikova, O. V.; Sugiyama, K.; Schwarz-Selinger, T.; Dürbeck, T.; Balden, M.

    2011-12-01

    Deuterium retention in different tungsten (W) coatings on carbon substrates was investigated for various incident ion energies ranging from 20 to 200 eV per deuterium atom and fluences ranging from 1 × 10 23 m -2 to 2 × 10 25 m -2. The targets were irradiated by deuterium ions at the IPP laboratory with a mass-separated ion beam with a flux of 10 19 D/m 2 s and with a deuterium plasma providing a flux of 10 20 D/m 2 s. Irradiation has been done at different sample temperatures ranging from 320 to 650 K. The depth profile of deuterium in the W coatings was measured up to 6 μm depth by nuclear reaction analysis (NRA) and the total retained amount was determined by thermal desorption spectroscopy. It is shown that deuterium retention significantly depends on the microstructure of each W coating. The deuterium retention in W coating of 7 μm thickness produced by combined magnetron-sputtering and ion implantation technique is higher compared to physical vapour deposited W coating of 4-5 μm thickness and 200 μm thickness plasma-sprayed W coating for all investigated energies and sample temperatures up to 650 K.

  7. Deuterium chemistry in the Orion Bar PDR. ``Warm'' chemistry starring CH{2}D^+

    NASA Astrophysics Data System (ADS)

    Parise, B.; Leurini, S.; Schilke, P.; Roueff, E.; Thorwirth, S.; Lis, D. C.

    2009-12-01

    Context: High levels of deuterium fractionation in gas-phase molecules are usually associated with cold regions, such as prestellar cores. Significant fractionation ratios are also observed in hot environments such as hot cores or hot corinos, where they are believed to be produced by the evaporation of the icy mantles surrounding dust grains, and are thus remnants of a previous cold (either gas-phase or grain surface) chemistry. The recent detection of DCN towards the Orion Bar, in a clump at a characteristic temperature of 70 K, has shown that high deuterium fractionation can also be detected in PDRs. The Orion Bar clumps thus appear to be a good environment for the observational study of deuterium fractionation in luke warm gas, allowing us to validate chemistry models for a different temperature range, where dominating fractionation processes are predicted to differ from those in cold gas (<20 K). Aims: We aimed to study observationally in detail the chemistry at work in the Orion Bar PDR, to understand whether DCN is either produced by ice mantle evaporation or is the result of warm gas-phase chemistry, involving the CH2D+ precursor ion (which survives higher temperatures than the usual H2D+ precursor). Methods: Using the APEX and the IRAM 30 m telescopes, we targeted selected deuterated species towards two clumps in the Orion Bar. Results: We confirmed the detection of DCN and detected two new deuterated molecules (DCO+ and HDCO) towards one clump in the Orion Bar PDR. Significant deuterium fractionations are found for HCN and H2CO, but we measured a low fractionation in HCO^+. We also provide upper limits to other molecules relevant to deuterium chemistry. Conclusions: We argue that grain evaporation in the clumps is unlikely to be a dominant process, and we find that the observed deuterium fractionation ratios are consistent with predictions of pure gas-phase chemistry models at warm temperatures (T ~ 50 K). We show evidence that warm deuterium chemistry

  8. Vanadium hydride deuterium-tritium generator

    DOEpatents

    Christensen, Leslie D.

    1982-01-01

    A pressure controlled vanadium hydride gas generator to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

  9. Measurement of Time-Dependent CP Asymmetries and the CP-Odd Fraction in the Decay B0->D*+D*-

    SciTech Connect

    Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; Palano, A.; Pappagallo, M.; Pompili, A.; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; Eigen, G.; Ofte, I.; Stugu, B. /Bergen U. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Harvard U. /Heidelberg U. /Imperial Coll., London /Iowa U. /Iowa State U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Naples U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /INFN, Padua /Paris U., VI-VII /Pennsylvania U. /Perugia U. /INFN, Perugia /Pisa U. /INFN, Pisa /Prairie View A-M /Princeton U. /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Stony Brook /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /INFN, Turin /Trieste U. /INFN, Trieste /Valencia U., IFIC /Vanderbilt U. /Victoria U. /Warwick U. /Wisconsin U., Madison /Yale U.

    2005-07-06

    We present an updated measurement of time-dependent CP asymmetries and the CP-odd fraction in the decay B{sup 0} D*{sup +}D*{sup -} using 232 x 10{sup 6} B{bar B} pairs collected by the BABAR detector at the PEP-II B factory. We determine the CP-odd fraction to be 0.125 {+-} 0.044(stat) {+-} 0.007(syst). The time-dependent CP asymmetry parameters C{sub +} and S{sub +} are determined to be 0.06 {+-} 0.17(stat) {+-} 0.03(syst) and -0.75 {+-} 0.25(stat) {+-} 0.03(syst), respectively. The Standard Model predicts these parameters to be 0 and -sin2{beta}, respectively, in the absence of penguin amplitude contributions.

  10. Measurement of time-dependent CP asymmetries and the CP-odd fraction in the decay B0-->D(*+)D(*-).

    PubMed

    Aubert, B; Barate, R; Boutigny, D; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kral, J F; Kukartsev, G; LeClerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Romosan, A; Ronan, M T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Knowles, D J; Morgan, S E; Penny, R C; Watson, A T; Watson, N K; Deppermann, T; Goetzen, K; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Barlow, N R; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Mackay, C; Wilson, F F; Abe, K; Cuhadar-Donszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; McKemey, A K; Blinov, V E; Bukin, A D; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Chao, M; Kirkby, D; Lankford, A J; Mandelkern, M; McMahon, S; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, Sh; Schwanke, U; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Kuznetsova, N; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Beringer, J; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Turri, M; Walkowiak, W; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Barillari, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Dubitzky, R S; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, K R; Schwierz, R; Spaan, B; Wilden, L; Bernard, D; Bonneaud, G R; Brochard, F; Cohen-Tanugi, J; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Khan, A; Lavin, D; Muheim, F; Playfer, S; Swain, J E; Tinslay, J; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Falciai, D; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Pastore, F C; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Morii, M; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Eschrich, I; Gaillard, J R; Morton, G W; Nash, J A; Sanders, P; Taylor, G P; Grenier, G J; Lee, S-J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Brigljević, V; Cheng, C H; Lange, D J; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, E; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Shorthouse, H W; Strother, P; Vidal, P B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, R J; Hart, P A; Forti, A C; Jackson, F; Lafferty, G D; Lyon, A J; Weatherall, J H; Williams, J C; Farbin, A; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Milek, M; Patel, P M; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Hast, C; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; LoSecco, J M; Gabriel, T A; Brau, B; Pulliam, T; Wong, Q K; Brau, J; Frey, R; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; de la Vaissière, Ch; Del Buono, L; Hamon, O; John, M J J; Leruste, Ph; Ocariz, J; Pivk, M; Roos, L; Stark, J; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Gladney, L; Guo, Q H; Panetta, J; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martinez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lu, C; Miftakov, V; Olsen, J; Smith, A J S; Tanaka, H A; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Safai Tehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Hamel de Monchenault, G; Kozanecki, W; Langer, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yeche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Convery, M R; Coupal, D P; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Grauges-Pous, E; Hadig, T; Halyo, V; Hryn'ova, T; Innes, W R; Jessop, C P; Kelsey, M H; Kim, P; Kocian, M L; Langenegger, U; Leith, D W G S; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Menke, S; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Robertson, S H; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Va'vra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wright, D H; Young, C C; Burchat, P R; Edwards, A J; Meyer, T I; Roat, C; Ahmed, S; Alam, M S; Ernst, J A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Hu, H; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihalyi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

    2003-09-26

    We present a measurement of time-dependent CP asymmetries and an updated determination of the CP-odd fraction in the decay B0-->D(*+)D(*-) using a data sample of 88x10(6)BB pairs collected by the BABAR detector at the PEP-II B Factory at SLAC. We determine the CP-odd fraction to be 0.063+/-0.055(stat)+/-0.009(syst). The time-dependent CP asymmetry parameters Im(lambda(+)) and /lambda(+)/ are determined to be 0.05+/-0.29(stat)+/-0.10(syst) and 0.75+/-0.19(stat)+/-0.02(syst), respectively. The standard model predicts these parameters to be -sin(2beta and 1, respectively, in the absence of penguin diagram contributions. PMID:14525298

  11. Measurement of time-dependent CP asymmetries and the CP-odd fraction in the decay B0-->D*+D*-.

    PubMed

    Aubert, B; Barate, R; Boutigny, D; Couderc, F; Karyotakis, Y; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Grauges, E; Palano, A; Pappagallo, M; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schroeder, T; Steinke, M; Boyd, J T; Burke, J P; Chevalier, N; Cottingham, W N; Kelly, M P; Cuhadar-Donszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Teodorescu, L; Blinov, A E; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bondioli, M; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Weinstein, A J R; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Zhang, L; Del Re, D; Hadavand, H K; Hill, E J; Macfarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Andreassen, R; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Blanc, F; Bloom, P; Chen, S; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Ruddick, W O; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q; Altenburg, D; Feltresi, E; Hauke, A; Spaan, B; Brandt, T; Brose, J; Dickopp, M; Klose, V; Lacker, H M; Nogowski, R; Otto, S; Petzold, A; Schott, G; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Bernard, D; Bonneaud, G R; Grenier, P; Schrenk, S; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Won, E; Wu, J; Dubitzky, R S; Langenegger, U; Marks, J; Schenk, S; Uwer, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Flack, R L; Gaillard, J R; Morton, G W; Nash, J A; Nikolich, M B; Taylor, G P; Vazquez, W P; Charles, M J; Mader, W F; Mallik, U; Mohapatra, A K; Cochran, J; Crawley, H B; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Yi, J; Arnaud, N; Davier, M; Giroux, X; Grosdidier, G; Höcker, A; Le Diberder, F; Lepeltier, V; Lutz, A M; Oyanguren, A; Petersen, T C; Pierini, M; Plaszczynski, S; Rodier, S; Roudeau, P; Schune, M H; Stocchi, A; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Coleman, J P; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Parry, R J; Payne, D J; Schofield, K C; Touramanis, C; Cormack, C M; Di Lodovico, F; Sacco, R; Brown, C L; Cowan, G; Flaecher, H U; Green, M G; Hopkins, D A; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hodgkinson, M C; Lafferty, G D; Naisbit, M T; Williams, J C; Chen, C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Kofler, R; Koptchev, V B; Li, X; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Koeneke, K; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Kim, H; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Viaud, B; Nicholson, H; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Wilden, L; Jessop, C P; Losecco, J M; Allmendinger, T; Benelli, G; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonyan, R; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Lu, M; Potter, C T; Sinev, N B; Strom, D; Strube, J; Torrence, E; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; Del Buono, L; de la Vaissière, Ch; Hamon, O; John, M J J; Leruste, Ph; Malclès, J; Ocariz, J; Roos, L; Therin, G; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Biasini, M; Covarelli, R; Pacetti, S; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bucci, F; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Walsh, J; Haire, M; Judd, D; Wagoner, D E; Biesiada, J; Danielson, N; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Tehrani, F Safai; Voena, C; Schröder, H; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Gopal, G P; Olaiya, E O; Wilson, F F; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Graziani, G; Hamel de Monchenault, G; Kozanecki, W; Legendre, M; London, G W; Mayer, B; Vasseur, G; Yèche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Wilson, J R; Yumiceva, F X; Abe, T; Allen, M T; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Claus, R; Convery, M R; Cristinziani, M; Dingfelder, J C; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Fan, S; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hast, C; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S; Thompson, J M; Va'vra, J; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Vitale, L; Martinez-Vidal, F; Panvini, R S; Banerjee, Sw; Bhuyan, B; Brown, C M; Fortin, D; Hamano, K; Kowalewski, R; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Eichenbaum, A M; Flood, K T; Graham, M; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Mellado, B; Mihalyi, A; Pan, Y; Prepost, R; Tan, P; von Wimmersperg-Toeller, J H; Wu, S L; Yu, Z; Neal, H

    2005-10-01

    We present an updated measurement of time-dependent CP asymmetries and the CP-odd fraction in the decay B0-->D*+D*- using 232x10(6)BB pairs collected by the BABAR detector at the SLAC PEP-II B factory. We determine the CP-odd fraction to be 0.125+/-0.044(stat)+/-0.007(syst). The time-dependent CP asymmetry parameters C+ and S+ are determined to be 0.06+/-0.17(stat)+/-0.03(syst) and -0.75+/-0.25(stat)+/-0.03(syst), respectively. The standard model predicts these parameters to be 0 and -sin2beta, respectively, in the absence of penguin amplitude contributions. PMID:16241717

  12. Ignition of a Deuterium Micro-Detonation with a Gigavolt Super Marx Generator

    NASA Astrophysics Data System (ADS)

    Winterberg, Friedwardt

    2009-09-01

    The Centurion-Halite experiment demonstrated the feasibility of igniting a deuterium-tritium micro-explosion with an energy of not more than a few megajoule, and the Mike test, the feasibility of a pure deuterium explosion with an energy of more than 106 MJ. In both cases the ignition energy was supplied by a fission bomb explosive. While an energy of a few megajoule, to be released in the time required of less than 10-9 s, can be supplied by lasers and intense particle beams, this is not enough to ignite a pure deuterium explosion. Because the deuterium-tritium reaction depends on the availability of lithium, the non-fission ignition of a pure deuterium fusion reaction would be highly desirable. It is shown that this goal can conceivably be reached with a "Super Marx Generator", where a large number of "ordinary" Marx generators charge (magnetically insulated) fast high voltage capacitors of a second stage Marx generator, called a "Super Marx Generator", ultimately reaching gigavolt potentials with an energy output in excess of 100 MJ. An intense 107 Ampere-GeV proton beam drawn from a "Super Marx Generator" can ignite a deuterium thermonuclear detonation wave in a compressed deuterium cylinder, where the strong magnetic field of the proton beam entraps the charged fusion reaction products inside the cylinder. In solving the stand-off problem, the stiffness of a GeV proton beam permits to place the deuterium target at a comparatively large distance from the wall of a cavity confining the deuterium micro-explosion.

  13. Theoretical study of the voltage and concentration dependence of the anomalous mole fraction effect in single calcium channels. New insights into the characterization of multi-ion channels.

    PubMed Central

    Campbell, D L; Rasmusson, R L; Strauss, H C

    1988-01-01

    Several recent independent studies on macroscopic Ca currents have demonstrated the anomalous mole fraction effect in mixtures of Ca and Ba at concentrations of 10 mM or less. Recently, Hess and Tsien (1984; Nature 309) proposed a dual binding site model, based upon Eyring rate theory, to account for this effect in L-type cardiac Ca channels. This model predicts that the anomalous mole fraction effect can be accounted for solely in terms of open single channel permeation properties; it was able to adequately reproduce the effect for macroscopic Ca currents recorded in 10 mM solutions. However, the electrochemical gradients under which single Ca channel current recordings are routinely made with the patch clamp technique vary dramatically from those used for macroscopic Ca currents. To properly assess the general validity of the Hess and Tsien model at the single Ca channel level, the effects of both large electrical potentials and elevated divalent concentrations must be understood. Computer simulations were therefore carried out using the original parameters used by Hess and Tsien under conditions designed to mimic those used in patch clamp studies. The permeation behavior generated by this model is quite complex. In particular, hyperpolarization and increased divalent concentration combine to reduce and ultimately abolish the anomalous mole fraction effect. It may therefore be very difficult to observe the anomalous mole fraction effect at the single Ca channel level; the dual-site model displays a relationship between current and mole fraction generally associated with a single-site model under the conditions frequently employed to resolve single Ca channel activity. Nonetheless, analysis of such monotonic mole fraction behavior can still be used as a test for the general validity of the dual-site model. Apparent Kms for Ca and Ba can be extracted from such monotonic behavior, and may not only be functions of membrane potential but may also depend upon the total

  14. High-dose total-body irradiation and autologous marrow reconstitution in dogs: dose-rate-related acute toxicity and fractionation-dependent long-term survival

    SciTech Connect

    Deeg, H.J.; Storb, R.; Weiden, P.L.; Schumacher, D.; Shulman, H.; Graham, T.; Thomas, E.D.

    1981-11-01

    Beagle dogs treated by total-body irradiation (TBI) were given autologous marrow grafts in order to avoid death from marrow toxicity. Acute and delayed non-marrow toxicities of high single-dose (27 dogs) and fractionated TBI (20 dogs) delivered at 0.05 or 0.1 Gy/min were compared. Fractionated TBI was given in increments of 2 Gy every 6 hr for three increments per day. Acute toxicity and early mortality (<1 month) at identical total irradiation doses were comparable for dogs given fractionated or single-dose TBI. With single-dose TBI, 14, 16, and 18 Gy, respectively, given at 0.05 Gy/min, 0/5, 5/5, and 2/2 dogs died from acute toxicity; with 10, 12, and 14 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 5/5 dogs died acutely. With fractionated TBI, 14 and 16 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 2/2 dogs died auctely. Early deaths were due to radiation enteritis with or without associated septicemia (29 dogs; less than or equal to Day 10). Three dogs given 10 Gy of TBI at 0.1 Gy/min died from bacterial pneumonia; one (Day 18) had been given fractionated and two (Days 14, 22) single-dose TBI. Fifteen dogs survived beyond 1 month; eight of these had single-dose TBI (10-14 Gy) and all died within 7 months of irradiation from a syndrome consisting of hepatic damage, pancreatic fibrosis, malnutrition, wasting, and anemia. Seven of the 15 had fractionated TBI, and only one (14 Gy) died on Day 33 from hepatic failure, whereas 6 (10-14 Gy) are alive and well 250 to 500 days after irradiation. In conclusion, fractionated TBI did not offer advantages over single-dose TBI with regard to acute toxicity and early mortality; rather, these were dependent upon the total dose of TBI. The total acutely tolerated dose was dependent upon the exposure rate; however, only dogs given fractionated TBI became healthy long-term survivors.

  15. A study of the substance dependence effect of the ethanolic extract and iridoid-rich fraction from Valeriana jatamansi Jones in mice

    PubMed Central

    Yu, Lin; Ke-ke, Xu; Chao-yong, Chen; Rui-tong, Zhang; Ming, Lan; Shao-hua, Li; Ling-zhen, Pan; Tian-e, Zhang; Zhi-yong, Yan

    2015-01-01

    Background: Recently we found the ethanolic extract and iridoid-rich fraction from Valeriana jatamansi Jones, which is a traditional Chinese medicine exhibited anxiolytic properties. Objective: This study aims to the substance dependence effect of the ethanolic extract and iridoid-rich fraction. Materials and Methods: The study included two experiments: Mice were given orally with ethanolic extract for 12 weeks or iridoid-rich fraction for 16 weeks in experiment I and experiment II, respectively. Diazepam was used as a control drug and the normal mice groups were administered with 0.5% carboxymethyl cellulose Na in both experiments. All groups were administered twice daily. Natural withdrawal symptoms, withdrawal-induced body weight change, audiogenic tail-erection test (in experiment I), and pentylenetetrazol (PTZ)-induced convulsion test (in experiment II) were measured. Results: (1) Compared to normal group in both experiments, the diazepam-treated group exhibited obvious withdrawal symptoms of tail-erection, irritability, teeth chattering, etc; the body weight of them after withdrawal had a period of significant loss (P < 0.05 or P < 0.01); and the ratios of tail-erection and seizure in two experiments were improved significantly when mice were induced by mixer noise ringtone (experiment I) or PTZ (experiment II) (P < 0.05 or P < 0.01).(2) In experiment I and II, there were no significant differences between mice that received ethanolic extract or iridoid-rich fraction and normal group in terms of natural withdrawal symptoms and withdrawal-induced body weight change (P > 0.05); in audiogenic tail-erection test, it found that the significant difference compared with normal group was just in ethanolic extract 900 mg/kg dose group on week 8 (P < 0.05); in PTZ-induced convulsion test, mice in iridoid-rich fraction groups had a slightly tail-erection and seizure, all results of them were with no significant difference compare to normal mice (P > 0.05), while

  16. A fraction from Dojuksan 30% ethanol extract exerts its anti-inflammatory effects through Nrf2-dependent heme oxygenase-1 expression.

    PubMed

    Lee, Dong-Sung; Kim, Kyoung-Su; Ko, Wonmin; Bae, Gi-Sang; Park, Sung-Joo; Jang, Jun-Hyeog; Oh, Hyuncheol; Kim, Youn-Chul

    2016-02-01

    Dojuksan is a traditional herbal medicine used in Korea and China to treat urinary diseases. In the present study, we aimed to examine the anti-inflammatory effects of an ethanol solvent extract of Dojuksan and a fraction (by bioassay-guided fractionation) derived from this extract, and to elucidate the specific mechanisms involved. The Dojuksan 30% ethanol extract (DEE) had a more significant and potent anti-inflammatory effect than the Dojuksan water extract (DWE). DEE markedly inhibited the production of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), as well as nuclear factor-κB (NF-κB) binding activity. We found that the anti-inflammatory effects of DEE were mediated by the induction of nuclear factor E2-related factor 2 (Nrf2)-dependent heme oxygenase-1 (HO-1). To further explore the anti-inflammatory effects of DEE, we generated 6 different fractions of DEE. Of these, DEE-5 decreased the production of NO more significantly than the other fractions. DEE-5 also significantly decreased the expression of iNOS and COX-2, and the production of NO, PGE2, TNF-α and IL-1β. In addition, DEE-5 also significantly increased HO-1 levels; HO-1 significanlty contributed to the inhibitory effects of DEE-5 on the production of pro-inflammatory mediators. In this study, we determined whether the choice of extraction solvent affects the biological activity of Dojuksan, a traditional herbal formula. Our findings demonstrate that DEE and a fraction derived from this extract exerts anti-inflammatory effects through Nrf2‑dependent HO-1 expression, and that DEE may thus have greater potential therapeutic application than DWE. PMID:26647788

  17. Investigations of chemical erosion of carbon materials in hydrogen and deuterium low pressure plasmas

    NASA Astrophysics Data System (ADS)

    Starke, P.; Fantz, U.; Balden, M.

    2005-03-01

    Investigations on chemical erosion of pure and carbide-doped graphite materials were carried out in inductively coupled RF plasmas containing hydrogen, deuterium or a mixture of both in helium. For extrapolations of erosion yields to future fusion devices the relevant particle fluxes have to be known precisely. This was done by several diagnostic techniques. In particular the ion fluxes are determined by an energy mass analyzer. An isotope effect of the ion composition is measured resulting in an enhanced erosion of graphite in deuterium plasmas. Since in fusion plasmas a mixture of deuterium and tritium will interact with the surface, a mixture of hydrogen and deuterium on graphite was investigated as well. In order to reduce erosion yields doping of carbon is under discussion. Therefore, fluence dependent erosion yields of several W-, Ti-, V- and Zr-doped graphite materials are measured and compared with pure graphite.

  18. Hydrogen/deuterium exchange on aromatic rings during atmospheric pressure chemical ionization mass spectrometry.

    PubMed

    Davies, Noel W; Smith, Jason A; Molesworth, Peter P; Ross, John J

    2010-04-15

    It has been demonstrated that substituted indoles fully labelled with deuterium on the aromatic ring can undergo substantial exchange back to partial and even fully protonated forms during atmospheric pressure chemical ionisation (APCI) liquid chromatography/mass spectrometry (LC/MS). The degree of this exchange was strongly dependent on the absolute quantity of analyte, the APCI desolvation temperature, the nature of the mobile phase, the mobile phase flow rate and the instrument used. Hydrogen/deuterium (H/D) exchange on several other aromatic ring systems during APCI LC/MS was either undetectable (nitrobenzene, aniline) or extremely small (acetanilide) compared to the effect observed for substituted indoles. This observation has major implications for quantitative assays using deuterium-labelled internal standards and for the detection of deuterium-labelled products from isotopically labelled feeding experiments where there is a risk of back exchange to the protonated form during the analysis. PMID:20213724

  19. Impact-induced devolatilization and hydrogen isotopic fractionation of serpentine: Implications for planetary accretion

    NASA Technical Reports Server (NTRS)

    Tyburczy, James A.; Krishnamurthy, R. V.; Epstein, Samuel; Ahrens, Thomas J.

    1988-01-01

    Impact-induced devolatilization of porous serpentine was investigated using two independent experimental methods, the gas recovery and the solid recovery method, each yielding nearly identical results. For shock pressures near incipient devolatilization, the hydrogen isotopic composition of the evolved H2O is very close to that of the starting material. For shock pressures at which up to 12 percent impact-induced devolatilization occurs, the bulk evolved gas is significantly lower in deuterium than the starting material. There is also significant reduction of H2O to H2 in gases recovered at these higher shock pressures, probably caused by reaction of evolved H2O with the metal gas recovery fixture. Gaseous H2O-H2 isotopic fractionation suggests high temperature isotopic equilibrium between the gaseous species, indicating initiation of devolatilization at sites of greater than average energy deposition. Bulk gas-residual solid isotopic fractionations indicate nonequilibrium, kinetic control of gas-solid isotopic ratios. Impact-induced hydrogen isotopic fractionation of hydrous silicates during accretion can strongly affect the long-term planetary isotopic ratios of planetary bodies, leaving the interiors enriched in deuterium. Depending on the model used for extrapolation of the isotopic fractionation to devolatilization fractions greater than those investigated experimentally can result from this process.

  20. Deuterium and the stellar birthline

    NASA Technical Reports Server (NTRS)

    Stahler, Steven W.

    1988-01-01

    A series of simplified evolutionary calculations are used to show that deuterium burning acts as an effective thermostat in low-mass protostars over a plausible range of initial conditions and mass accretion rates. The thermostat keeps the central temperature of the accreting hydrostatic core close to 10 to the 6th K, and thereby tightly constrains the core's mass-radius relation. This relation, when combined with premain-sequence evolutionary tracks, yields a theoretical birthline or upper envelope for young stars in the H-R diagram which maintains excellent agreement with observations of T Tauri stars in nearby molecular cloud complexes. This derivation of the birthline helps to explain its insensitivity to protostellar collapse conditions. The calculations indicate that the birthline will be little affected by the inclusion of rotation as long as the newly visible stars have lost most of their accreted angular momentum.

  1. Deuterium gas puff Z-pinch at currents of 2 to 3 mega-ampere

    NASA Astrophysics Data System (ADS)

    Klir, D.; Shishlov, A. V.; Kubes, P.; Rezac, K.; Fursov, F. I.; Kokshenev, V. A.; Kovalchuk, B. M.; Kravarik, J.; Kurmaev, N. E.; Labetsky, A. Yu.; Ratakhin, N. A.

    2012-03-01

    Deuterium gas-puff experiments have been carried out on the GIT-12 generator at the Institute of High Current Electronics in Tomsk. The emphasis was put on the study of plasma dynamics and neutron production in double shell gas puffs. A linear mass density of deuterium (D2) varied between 50 and 85 μg/cm. Somewhat problematic was a spread of the D2 gas at a large diameter in the central anode-cathode region. The generator operated in two regimes, with and without a plasma opening switch (POS). When the POS was used, a current reached a peak of 2.7 MA with a 200 ns rise time. Without the POS, a current rise time approached 1500 ns. The influence of different current rise times on neutron production was researched. Obtained results were important for comparison of fast deuterium Z-pinches with plasma foci. Average DD neutron yields with and without the POS were about 1011. The neutron yield seems to be dependent on a peak voltage at the Z-pinch load. In all shots, the neutron emission started during stagnation. At the beginning of the neutron production, the neutron emission correlated with soft x-rays and a significant fraction of neutrons could be explained by the thermonuclear mechanism. Nevertheless, a peak of the neutron emission occurred 40 ns after a soft x-ray peak. At this very moment, hard x-rays above 1 MeV were detected and a rapid expansion with a velocity of 3×105 m/s was observed. In the case of the POS, 1 MeV widths of radial neutron spectra implied that there are deuterons with the energy above 200 keV moving in the radial direction. On the basis of D2 gas puff experiments in the 0.3-17 MA region, the neutron yield dependence on a current as Y∝I3.0±0.2 was proposed.

  2. First observation of muonic hyperfine effects in pure deuterium

    SciTech Connect

    Kammel, P.; Breunlich, W.H.; Cargnelli, M.; Mahler, H.G.; Zmeskal, J.; Bertl, W.H.; Petitjean, C.

    1983-11-01

    We discovered a strong hyperfine dependence of the resonant formation process of d..mu..d mesomolecules, while detecting neutrons from muon-catalyzed fusion in pure deuterium gas at 34 K. This new effect enabled us to observe directly transitions between hyperfine states of the ..mu..d atom for the first time and to determine an accurate experimental value for this transition rate. Our analysis demonstrates the importance of hyperfine effects for the quantitative understanding of the mechanism of resonant d..mu..d formation. Moreover, this experiment indicates that the resonant formation process is a powerful tool for a refined spectroscopy of d..mu..d bound states. Finally, the detailed knowledge about mesoatomic and mesomolecular processes obtained in this work provides valuable information for the analysis of experiments on the elementary muon-capture process in deuterium.

  3. Muon transfer from hydrogen and deuterium atoms to neon

    SciTech Connect

    Jacot-Guillarmod, R. )

    1995-03-01

    The muon exchange reactions from the ground state of muonic protium and deuterium atoms to neon are studied. Measurements have been performed in binary gas mixtures at room temperature. The transfer rate from thermalized muonic deuterium is found to exceed by about an order of magnitude the one from muonic protium. On the other hand, an energy dependence of the rate from [mu][ital d] is revealed, while none is observed from [mu][ital p]. The intensity patterns of the muonic Lyman series of neon resulting from the muon exchange differ from one hydrogen isotope to the other, the most obvious discrepancy being the presence of the muonic Ne(7-1) line after transfer from [mu][ital d], whereas this line is absent by transfer from [mu][ital p]. This indicates that the muon is transferred to the level [ital n][sub [ital p

  4. CO2-dependent fractional crystallization of alkaline silicate magmas and unmixing of carbonatites within the intrusive complexes of Brava Island (Cape Verde)

    NASA Astrophysics Data System (ADS)

    Weidendorfer, D.; Schmidt, M. W.; Mattsson, H. B.

    2014-12-01

    Intrusive carbonatites often occur in intimate association with SiO2-undersaturated rocks such as melilitites, nephelinites, syenites and phonolites. The occurrence of carbonatites on five of the 10 main islands of the Cape Verde hotspot argues for a CO2-enriched mantle source. Whether alkali-poor carbonatites on the Cape Verdes directly represent small mantle melt fractions or form by extreme fractionation and/or liquid immiscibility from a CO2-rich silicate magma remains a matter of debate. This study focuses on the pyroxenites, nephelinites, ijolites, syenites, phonolites and carbonatites of the intrusive unit of Brava Island. This relative complete series allows for the deduction of a CO2-dependent fractionation pathway from the most primitive basanitic dikes towards phonolitic compositions through an ijolitic series. Major and trace element whole rock and mineral composition trends can be reproduced by fractionating a sequence of olivine, augite, perovskite, biotite, apatite, sodalite and FeTi-oxides, present as phenocrysts in the rocks corresponding to their fractionation interval. To reproduce the observed chemistry of the alkaline silicate rocks a total fractionation of ~87% is required. The melts evolve towards the carbonatite-silicate miscibility gap, an initial CO2 of 0.5 wt% would be sufficient to maintain CO2-saturation in the more evolved compositions. The modelled carbonatite compositions, conjugate to nepheline-syenites to phonolites, correspond well to the observed ones except for an alkali-enrichment with respect to the natural samples. The alkali-depleted nature of the small carbonatite intrusions and dikes on Brava is likely a consequence of fluid-release to the surrounding wall-rocks during crystallization, where fenitization can be observed. The trace element chemistry of primary carbonates and also cpx within both, the carbonatites and the associated silicate rocks, substantiates our fractionation model. Furthermore, carbonatite and silicate

  5. Simultaneous experimental determination of labile proton fraction ratio and exchange rate with irradiation radio frequency power-dependent quantitative CEST MRI analysis.

    PubMed

    Sun, Phillip Zhe; Wang, Yu; Xiao, Gang; Wu, Renhua

    2013-01-01

    Chemical exchange saturation transfer (CEST) imaging is sensitive to dilute proteins/peptides and microenvironmental properties, and has been increasingly evaluated for molecular imaging and in vivo applications. However, the experimentally measured CEST effect depends on the CEST agent concentration, exchange rate and relaxation time. In addition, there may be non-negligible direct radio-frequency (RF) saturation effects, particularly severe for diamagnetic CEST (DIACEST) agents owing to their relatively small chemical shift difference from that of the bulk water resonance. As such, the commonly used asymmetry analysis only provides CEST-weighted information. Recently, it has been shown with numerical simulation that both labile proton concentration and exchange rate can be determined by evaluating the RF power dependence of DIACEST effect. To validate the simulation results, we prepared and imaged two CEST phantoms: a pH phantom of serially titrated pH at a fixed creatine concentration and a concentration phantom of serially varied creatine concentration titrated to the same pH, and solved the labile proton fraction ratio and exchange rate per-pixel. For the concentration phantom, we showed that the labile proton fraction ratio is proportional to the CEST agent concentration with negligible change in the exchange rate. Additionally, we found the exchange rate of the pH phantom is dominantly base-catalyzed with little difference in the labile proton fraction ratio. In summary, our study demonstrated quantitative DIACEST MRI, which remains promising to augment the conventional CEST-weighted MRI analysis. PMID:23606428

  6. Isolation of CA1 nuclear enriched fractions from hippocampal slices to study activity-dependent nuclear import of synapto-nuclear messenger proteins.

    PubMed

    Yuanxiang, Pingan; Bera, Sujoy; Karpova, Anna; Kreutz, Michael R; Mikhaylova, Marina

    2014-01-01

    Studying activity dependent protein expression, subcellular translocation, or phosphorylation is essential to understand the underlying cellular mechanisms of synaptic plasticity. Long-term potentiation (LTP) and long-term depression (LTD) induced in acute hippocampal slices are widely accepted as cellular models of learning and memory. There are numerous studies that use live cell imaging or immunohistochemistry approaches to visualize activity dependent protein dynamics. However these methods rely on the suitability of antibodies for immunocytochemistry or overexpression of fluorescence-tagged proteins in single neurons. Immunoblotting of proteins is an alternative method providing independent confirmation of the findings. The first limiting factor in preparation of subcellular fractions from individual tetanized hippocampal slices is the low amount of material. Second, the handling procedure is crucial because even very short and minor manipulations of living slices might induce activation of certain signaling cascades. Here we describe an optimized workflow in order to obtain sufficient quantity of nuclear enriched fraction of sufficient purity from the CA1 region of acute hippocampal slices from rat brain. As a representative example we show that the ERK1/2 phosphorylated form of the synapto-nuclear protein messenger Jacob actively translocates to the nucleus upon induction of LTP and can be detected in a nuclear enriched fraction from CA1 neurons. PMID:25145907

  7. The effect of propylene glycol on the P450-dependent metabolism of acetaminophen and other chemicals in subcellular fractions of mouse liver

    SciTech Connect

    Snawder, J.E.; Benson, R.W.; Leakey, J.E.A.; Roberts, D.W. )

    1993-01-01

    Propylene glycol (PG) decreases the hepatotoxicity of acetominophen (APAP). To elucidate the mechanism for this response, the authors measured the effect of PG on the in vitro metabolism of APAP by subcellular liver fractions from 6-10 week-old male B6C3F1 mice. The fractions were assayed for their ability to bioactivate APAP to N-acetyl-p-benzoquinone imine, which was trapped as APAP-glutathione conjugates or APAP-protein adducts, and for dimethyl-nitrosamine-N-demethylase (DMN), 4-nitrophenol hydroxylase (4-NPOH), and phenacetin-O-deethylase (PAD) activities. Activity in the crude mitochondrial-rich (10,000 [times] g pellet) fraction was low and PG had no effect. PG inhibited DMN and 4-NPOH, indicators of IIE1-dependent activity, and the formation of APAP-glutathione conjugates and APAP-protein adducts in both heavy (15,000 [times] g pellet) and light (100,000 [times] g pellet) microsomes. PAD, a measure of IA2-dependent activity, was not inhibited. These data demonstrate that PG selectively inhibits IIE1 activity, including the bioactivation of APAP, and implicates this as the mechanism for PG-mediated protection of APAP hepatotoxicity in mice. 27 refs., 1 fig., 1 tab.

  8. Simultaneous determination of labile proton fraction ratio and exchange rate with irradiation radio frequency (RF) power dependent quantitative CEST MRI analysis

    PubMed Central

    Sun, Phillip Zhe; Wang, Yu; Xiao, Gang; Wu, Renhua

    2014-01-01

    Chemical exchange saturation transfer (CEST) imaging is sensitive to dilute proteins/peptides and microenvironmental properties, and has been increasingly evaluated for molecular imaging and in vivo applications. However, the experimentally measured CEST effect depends on the CEST agent concentration, exchange rate and relaxation time. In addition, there may be non-negligible direct radio-frequency (RF) saturation effects, particularly severe for diamagnetic CEST (DIACEST) agents due to their relatively small chemical shift difference from that of the bulk water resonance. As such, the commonly used asymmetry analysis only provides CEST-weighted information. Recently, it has been shown with numerical simulation that both labile proton concentration and exchange rate can be determined by evaluating the RF power dependence of DIACEST effect. To validate the simulation results, we prepared and imaged two CEST phantoms: a pH phantom of serially titrated pH at a fixed creatine concentration and a concentration phantom of serially varied creatine concentration titrated to the same pH, and solved the labile proton fraction ratio and exchange rate per-pixel. For the concentration phantom, we showed that the labile proton fraction ratio is proportional to the CEST agent concentration with negligible change in the exchange rate. Additionally, we found the exchange rate of the pH phantom is dominantly base-catalyzed with little difference in the labile proton fraction ratio. In summary, our study demonstrated quantitative DIACEST MRI, which remains promising to augment the conventional CEST-weighted MRI analysis. PMID:23606428

  9. Measurements of the Branching Fraction and Time-Dependent CP Asymmetries of B0 to J/Psi pi0 Decays

    SciTech Connect

    George, K

    2006-03-10

    We present measurements of the branching fraction and time-dependent CP asymmetries in B{sup 0} {yields} J/{psi}{pi}{sup 0} decays based on (231.8 {+-} 2.6) x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. We obtain a branching fraction {Beta}(B{sup 0} {yields} J/{psi}{pi}{sup 0}) = (1.94 {+-} 0.22 (stat) {+-} 0.17 (syst)) x 10{sup -5}. We also measure the CP asymmetry parameters C = -0.21 {+-} 0.26 (stat) {+-} 0.06 (syst) and S = -0.68 {+-} 0.30 (stat) {+-} 0.04 (syst).

  10. Measurements of the Branching Fraction and Time-Dependent CP Asymmetries of B0 to J/Psi pi0 Decays.

    SciTech Connect

    Aubert, B.

    2005-08-04

    The authors present measurements of the branching fraction and time-dependent CP asymmetries in B{sup 0} {yields} J/{psi} {pi}{sup 0} decays based on (231.8 {+-} 2.6) x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC during the years 1999-2004. We obtain a branching fraction {Beta}(B{sup 0} {yields} J/{psi}{pi}{sup 0}) = (1.94 {+-} 0.22 (stat) {+-} 0.17 (syst)) x 10{sup -5}. They also measure the CP asymmetry parameters C = -0.21 {+-} 0.26 (stat) {+-} 0.09 (syst) and S = -0.68 {+-} 0.30 (stat) {+-} 0.04 (syst). All results presented in this paper are preliminary.

  11. Density dependent stopping power and muon sticking in muon catalyzed D-T fusion

    SciTech Connect

    Rafelski, H.E.; Mueller, B.

    1988-12-27

    The origin of the experimentally observed (1) density dependence of the muon alpha sticking fraction ..omega../sub s/ in muon catalyzed deuterium- tritium fusion is investigated. We show that the reactivation probability depends sensitively on the target stopping power at low ion velocities. The density dependence of the stopping power for a singly charged projectile in liquid heavy hydrogen is parametrized to simulate possible screening effects and a density dependent effective ionization potential. We find that, in principle, a description of the measured density dependence is possible, but the required parameters appear too large. Also, the discrepancy with observed (He..mu..) X-ray data widens.

  12. Water cluster-deuterium oxide collisions: An experimental glimpse

    SciTech Connect

    Kaiser, D.W.

    1993-01-01

    The wealth of cluster research now found in the literature is just beginning to bridge the gap between the study of molecule, surface, and condensed matter physics. Recent advances in experimental technology have opened up new windows into the world of cluster-molecule collision dynamics. This thesis is an attempt to present a glimpse into the collision dynamics of the water cluster-deuterium oxide system. An analysis of the potential reaction channels is presented and the cluster size dependence of the reaction cross section is detailed. An interpretation of this cluster size dependence is proposed.

  13. Deuterium-free water (1H2O) in complex life-support systems of long-term space missions.

    PubMed

    Sinyak, Y; Grigoriev, A; Gaydadimov, V; Gurieva, T; Levinskih, M; Pokrovskii, B

    2003-04-01

    Heavy water containing deuterium displays toxic property. It is stated that any quantity of a heavy isotope of hydrogen--deuterium--is undesirable to animals and plants. It was earlier shown by us that physical-chemical life support systems on board the "MIR" station fractionate (change) isotopes of hydrogen, oxygen and carbon. Therefore, the problem of regenerative systems in habitable space objects should include removal, from water, of a heavy stable isotope of hydrogen--deuterium. In this article we consider one method of obtaining deuterium-free water--decomposition of distillate water in an electrolyser to hydrogen and oxygen with subsequent synthesis in a catalytic or high-temperature reactor. The influence of deuterium-free water on the growth and development of Arabidopsis thaliana and Japanese quail is investigated. It is shown that with the help of the electrolysis method it is possible to fabricate water containing 80% less deuterium in comparison with SMOW. Experimentally, it is proved on a culture of Arabidopsis thaliana and Japanese quail that water with reduced contents of deuterium (80%) displays positive biological activity. PMID:12575722

  14. Deuterium nuclear magnetic resonance unambiguously quantifies pore and collagen-bound water in cortical bone

    PubMed Central

    Ong, Henry H.; Wright, Alexander C.; Wehrli, Felix W.

    2012-01-01

    Bone water (BW) plays a pivotal role in nutrient transport and conferring bone with its viscoelastic mechanical properties. BW is partitioned between the pore spaces of the Haversian and lacuno-canalicular system, and water predominantly bound to the matrix proteins (essentially collagen). The general model of BW is that the former predominantly experiences fast isotropic molecular reorientation, whereas water in the bone matrix undergoes slower anisotropic rotational diffusion. Here, we provide direct evidence for the correctness of this model and show that unambiguous quantification in situ of these two functionally and dynamically different BW fractions is possible. The approach chosen relies on nuclear magnetic resonance (NMR) of deuterium (2H) that unambiguously separates and quantifies the two fractions on the basis of their distinguishing microdynamic properties. Twenty-four specimens of the human tibial cortex from six donors (3 male, 3 female, ages 27-83 years) were cored and 2H spectra recorded at 62 MHz (9.4 Tesla) on a Bruker Instruments DMX 400 spectrometer after exchange of native BW with 2H2O. Spectra consisted of a doublet signal resulting from quadrupole interaction of water bound to collagen. Doublet splittings were found to depend on the orientation of the osteonal axis with respect to the magnetic field direction (8.2 and 4.3 kHz for parallel and perpendicular orientation, respectively). In contrast, the isotropically reorienting pore-resident water yielded a single resonance line superimposed on the doublet. Nulling of the singlet resonance allowed separation of the two fractions. The results indicate that in human cortical bone 60-80% of detectable BW is collagen-bound. Porosity determined as the difference between total BW and collagen bound water fraction was found to strongly parallel μCT based measurements (R2 = 0.91). Our method provides means for direct validation of emerging relaxation-based measurements of cortical bone porosity by

  15. Characterization of deuterium clusters mixed with helium gas for an application in beam-target-fusion experiments

    DOE PAGESBeta

    Bang, W.; Quevedo, H. J.; Bernstein, A. C.; Dyer, G.; Ihn, Y. S.; Cortez, J.; Aymond, F.; Gaul, E.; Donovan, M. E.; Barbui, M.; et al

    2014-12-10

    We measured the average deuterium cluster size within a mixture of deuterium clusters and helium gas by detecting Rayleigh scattering signals. The average cluster size from the gas mixture was comparable to that from a pure deuterium gas when the total backing pressure and temperature of the gas mixture were the same as those of the pure deuterium gas. According to these measurements, the average size of deuterium clusters depends on the total pressure and not the partial pressure of deuterium in the gas mixture. To characterize the cluster source size further, a Faraday cup was used to measure themore » average kinetic energy of the ions resulting from Coulomb explosion of deuterium clusters upon irradiation by an intense ultrashort pulse. The deuterium ions indeed acquired a similar amount of energy from the mixture target, corroborating our measurements of the average cluster size. As the addition of helium atoms did not reduce the resulting ion kinetic energies, the reported results confirm the utility of using a known cluster source for beam-target-fusion experiments by introducing a secondary target gas.« less

  16. Characterization of deuterium clusters mixed with helium gas for an application in beam-target-fusion experiments

    SciTech Connect

    Bang, W.; Quevedo, H. J.; Bernstein, A. C.; Dyer, G.; Ihn, Y. S.; Cortez, J.; Aymond, F.; Gaul, E.; Donovan, M. E.; Barbui, M.; Bonasera, A.; Natowitz, J. B.; Albright, B. J.; Fernández, J. C.; Ditmire, T.

    2014-12-10

    We measured the average deuterium cluster size within a mixture of deuterium clusters and helium gas by detecting Rayleigh scattering signals. The average cluster size from the gas mixture was comparable to that from a pure deuterium gas when the total backing pressure and temperature of the gas mixture were the same as those of the pure deuterium gas. According to these measurements, the average size of deuterium clusters depends on the total pressure and not the partial pressure of deuterium in the gas mixture. To characterize the cluster source size further, a Faraday cup was used to measure the average kinetic energy of the ions resulting from Coulomb explosion of deuterium clusters upon irradiation by an intense ultrashort pulse. The deuterium ions indeed acquired a similar amount of energy from the mixture target, corroborating our measurements of the average cluster size. As the addition of helium atoms did not reduce the resulting ion kinetic energies, the reported results confirm the utility of using a known cluster source for beam-target-fusion experiments by introducing a secondary target gas.

  17. Deuterium desorption temperature of Mg-Ti composites prepared by the method of atom-by-atom component mixing

    NASA Astrophysics Data System (ADS)

    Morozov, O. M.; Kulish, V. G.; Zhurba, V. I.; Neklyudov, I. M.; Progolaieva, V. O.; Kuprin, A. S.; Lomino, N. S.; Ovcharenko, V. D.; Kolodiy, I. V.; Galitskiy, O. G.

    2013-12-01

    The plasma evaporation-sputtering method has been applied to obtain composite materials of the Mg-Ti system. Variations in the temperature of the ion-implanted deuterium desorption as a function of the component concentration are studied. It has been established, that introduction of titanium into magnesium leads to the significant decrease of deuterium desorption temperature, namely, to 400-450 K as compared to ~800 K in the case of deuterium release (desorption) from magnesium. The step-like shape of the deuterium desorption temperature curve evidences on the existence of two different structural states of the Mg-Ti composite depending on the ratio of components. The deuterium temperature drop can be caused by filamentary inclusions composed of titanium atoms in magnesium (insoluble component in magnesium) produced in the process of composite formation and providing the deuterium release from the sample at lower temperature (channels for deuterium diffusion and desorption through the surface barrier). The deuterium desorption data obtained on the example of Mg-Ti composites provide a support for further research into hydrogen storage materials containing not readily soluble chemical elements in the alloy components.

  18. Sulfur and oxygen isotope fractionation during sulfate reduction coupled to anaerobic oxidation of methane is dependent on methane concentration

    NASA Astrophysics Data System (ADS)

    Deusner, Christian; Holler, Thomas; Arnold, Gail L.; Bernasconi, Stefano M.; Formolo, Michael J.; Brunner, Benjamin

    2014-08-01

    to induce very large sulfur isotope fractionation between sulfate and sulfide (i.e. >60‰) and will drive the oxygen isotope composition of sulfate towards the sulfate-water oxygen isotope equilibrium value. Sulfur isotope fractionation by AOM-SR at gas seeps, where methane fluxes are high, will be much smaller (i.e. 20 to 40‰).

  19. Dose-dependent suppression of serum cholesterol by tocotrienol-rich fraction (TRF25) of rice bran in hypercholesterolemic humans.

    PubMed

    Qureshi, Asaf A; Sami, Saeed A; Salser, Winston A; Khan, Farooq A

    2002-03-01

    Tocotrienols are effective in lowering serum total and LDL-cholesterol levels by inhibiting the hepatic enzymic activity of beta-hydroxy-beta-methylglutaryl coenzymeA (HMG-CoA) reductase through the post-transcriptional mechanism. alpha-Tocopherol, however, has an opposite effect (induces) on this enzyme activity. Since tocotrienols are also converted to tocopherols in vivo, it is necessary not to exceed a certain dose, as this would be counter-productive. The present study demonstrates the effects of various doses of a tocotrienol-rich fraction (TRF25) of stabilized and heated rice bran in hypercholesterolemic human subjects on serum lipid parameters. Ninety (18/group) hypercholesterolemic human subjects participated in this study, which comprised three phases of 35 days each. The subjects were initially placed on the American Heart Association (AHA) Step-1 diet and the effects noted. They were then administered 25, 50, 100, and 200 mg/day of TRF25 while on the restricted (AHA) diet. The results show that a dose of 100 mg/day of TRF25 produce maximum decreases of 20, 25, 14 (P<0.05) and 12%, respectively, in serum total cholesterol, LDL-cholesterol, apolipoprotein B and triglycerides compared with the baseline values, suggesting that a dose of 100 mg/day TRF25 plus AHA Step-1 diet may be the optimal dose for controlling the risk of coronary heart disease in hypercholesterolemic human subjects. PMID:11882333

  20. Energy Levels of Hydrogen and Deuterium

    National Institute of Standards and Technology Data Gateway

    SRD 142 Energy Levels of Hydrogen and Deuterium (Web, free access)   This database provides theoretical values of energy levels of hydrogen and deuterium for principle quantum numbers n = 1 to 200 and all allowed orbital angular momenta l and total angular momenta j. The values are based on current knowledge of the revelant theoretical contributions including relativistic, quantum electrodynamic, recoil, and nuclear size effects.

  1. Vanadium hydride deuterium-tritium generator

    DOEpatents

    Christensen, L.D.

    1980-03-13

    A pressure controlled vanadium hydride gas generator was designed to provide deuterium-tritium gas in a series of pressure increments. A high pressure chamber filled with vanadium-deuterium-tritium hydride is surrounded by a heater which controls the hydride temperature. The heater is actuated by a power controller which responds to the difference signal between the actual pressure signal and a programmed pressure signal.

  2. Tempered fractional calculus

    NASA Astrophysics Data System (ADS)

    Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua

    2015-07-01

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.

  3. Tempered fractional calculus

    SciTech Connect

    Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua

    2015-07-15

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.

  4. Radio observations of D I and fractionation

    NASA Technical Reports Server (NTRS)

    Heiles, Carl; Mccullough, Peter R.; Glassgold, Alfred E.

    1993-01-01

    We report observations to detect the 327 MHz line of atomic deuterium in the primarily molecular clouds towards Cas A and Sgr A, making appropriate choices of spectral and spatial resolution. Our best results for Cas A, based on 1253 hr of observing with the 85 foot (26 m) Hat Creek telescope and 45 hr with the very large array (VLA), yield an upper limit for the fraction of deuterium in atomic form, D I, of 0.14. We present an approximate analytical analysis of deuterium fractionation in translucent clouds, which shows that gas-phase ion-molecule reactions, assisted by dust and HD line self-shielding, are efficient in converting deuterium to HD. We conclude that little atomic deuterium is present in the molecular clumps in the Cas A clouds and that much higher sensitivity observations would be required to detect 327 MHz line in molecular clouds. We have also attempted to detect the 72 GHz line of DCO(+) toward Cas A. The observed upper limit to the DCO(+)/HCO(+) ratio of approximately 0.03 is not much larger than our theoretical estimate, and the DCO(+) line should be detectable with existing instrumentation, unless the temperature of these clouds is much larger than usually assumed.

  5. Gas swelling and deuterium distribution in beryllium implanted with deuterium ions

    SciTech Connect

    Chernikov, V.N.; Alimov, V.Kh.; Zakharov, A.P.

    1995-09-01

    An extensive TEM study of the microstructure of Be TIP-30 irradiated with 3 and 10 keV D ions up to fluences, {Phi}, in the range from 3 x 10{sup 20} to 8 x 10{sup 21} D/m{sup 2} at temperatures T{sub irr} = 300 K, 500 K and 700 K has been carried out. Depth distributions of deuterium in the form of separate D atoms and D{sub 2} molecules have been investigated by means of SIMS and RGA methods, correspondingly. D ion irradiation is accompanied by blistering and gives rise to different kind of destructions depending mainly on the irradiation temperature. Irradiation with D ions at 300 K leads to the formation of tiny highly pressurized D{sub 2} bubbles reminiscent of He bubbles in Be. Under 3 keV D ion irradiation D{sub 2} bubbles ({bar r}{sub b} {approx} 0.7 nm) appear at a fluence as low as 3x10{sup 20} D/m{sup 2}. Irradiation at 500 K results in the development, along with relatively small facetted bubbles, of larger oblate gas-filled cavities accumulating most of injected D atoms and providing for much higher gas swelling values as compared to irradiation at 300 K. The increase of D and/or T{sub irr}, to 700 K causes the further coarsening of large cavities which are transformed into sub-surface labyrinth structures. D and He ion implantation leads to the enhanced growth of porous microcrystalline layers of c.p.h.-BeO oxide with a microstructure which differs considerably from that of oxide layers on electropolished surfaces of Be. Based on the analysis of experimental data questions of deuterium reemission, thermal desorption and trapping in Be have been discussed in detail.

  6. Transcription of fractionated mammalian chromatin by mammalian ribonucleic acid polymerase. Demonstration of temperature-dependent rifampicin-resistant initiation sites in euchromatin deoxyribonucleic acid

    PubMed Central

    Chesterton, C. James; Coupar, Barbara E. H.; Butterworth, Peter H. W.

    1974-01-01

    The chromatin fractionation method of Frenster et al. (1963) as modified by Leake et al. (1972) was used to prepare fragments of euchromatin from rat liver nuclei. These remain soluble in 5mm-MgCl2, and contain DNA of maximum mol.wt. 1×106–2×106. The fragments were separated from condensable chromatin on a sucrose gradient. Euchromatin contains endogenous DNA-dependent RNA polymerase, and most of the nascent RNA labelled in vivo or in vitro. Euchromatin fragments allow initiation of transcription by added purified rat liver form-B RNA polymerase and contain temperature-dependent rifampicin-resistant initiation sites for the form-B enzyme. These findings indicate that transcription of the euchromatin regions of interphase chromosomes is not initiated in condensed chromatin, but is initiated within the euchromatin stretches. Condensable chromatin also contains most of these activities, but is not associated with nascent RNA. PMID:4464858

  7. Anomalous density dependence of the activation gap of ν = 5/2 fractional quantum Hall state at extremely large Landau level mixing

    NASA Astrophysics Data System (ADS)

    Samkharadze, Nodar; Manfra, Michael; Pfeiffer, Loren; West, Ken; Csathy, Gabor

    2013-03-01

    We have conducted a study of the density dependence of ν = 5/2 fractional quantum Hall state (FQHS) in the regime of extremely low densities, down to n =4.9x10⌃10 cm⌃-2. In the density range accessed in our sample, the Landau level mixing parameter κ spans the so far unexplored range 2.52< κ<2.82. Here we observe an anomalous dependence of the activation gap of ν = 5/2 FQHS on the carrier density. We discuss the possible origins of this unexpected behavior. N.S. and G.C. were supported by the NSF grant DMR-0907172 and DMR-1207375. K. West and L. Pfeiffer acknowledge the support of the Princeton NSF-MRSEC and the Moore Foundation.

  8. Controlling the Neutron Yield from a Small Dense Plasma Focus using Deuterium-Inert Gas Mixtures

    SciTech Connect

    Bures, B. L.; Krishnan, M.; Eshaq, Y.

    2009-01-21

    The dense plasma focus (DPF) is a well known source of neutrons when operating with deuterium. The DPF is demonstrated to scale from 10{sup 4} n/pulse at 40 kA to >10{sup 12} n/pulse at 2 MA by non-linear current scaling as described in [1], which is itself based on the simple yet elegant model developed by Lee [2]. In addition to the peak current, the gas pressure controls the neutron yield. Recent published results suggest that mixing 1-5% mass fractions of Krypton increase the neutron yield per pulse by more than 10x. In this paper we present results obtained by mixing deuterium with Helium, Neon and Argon in a 500 J dense plasma focus operating at 140 kA with a 600 ns rise time. The mass density was held constant in these experiments at the optimum (pure) deuterium mass density for producing neutrons. A typical neutron yield for a pure deuterium gas charge is 2x10{sup 6}{+-}15% n/pulse. Neutron yields in excess of 10{sup 7}{+-}10% n/pulse were observed with low mass fractions of inert gas. Time integrated optical images of the pinch, soft x-ray measurements and optical emission spectroscopy where used to examine the pinch in addition to the neutron yield monitor and the fast scintillation detector. Work supported by Domestic Nuclear Detection Office under contract HSHQDC-08-C-00020.

  9. TEMPERED FRACTIONAL CALCULUS

    PubMed Central

    MEERSCHAERT, MARK M.; SABZIKAR, FARZAD; CHEN, JINGHUA

    2014-01-01

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series. PMID:26085690

  10. Determination of degradation rates of organic substances in the unsaturated soil zone depending on the grain size fractions of various soil types

    NASA Astrophysics Data System (ADS)

    Fichtner, Thomas; Stefan, Catalin; Goersmeyer, Nora

    2015-04-01

    Rate and extent of the biological degradation of organic substances during transport through the unsaturated soil zone is decisively influenced by the chemical and physical properties of the pollutants such as water solubility, toxicity and molecular structure. Furthermore microbial degradation processes are also influenced by soil-specific properties. An important parameter is the soil grain size distribution on which the pore volume and the pore size depends. Changes lead to changes in air and water circulation as well as preferred flow paths. Transport capacity of water inclusive nutrients is lower in existing bad-drainable fine pores in soils with small grain size fractions than in well-drainable coarse pores in a soil with bigger grain size fractions. Because fine pores are saturated with water for a longer time than the coarse pores and oxygen diffusion in water is ten thousand times slower than in air, oxygen is replenished much slower in soils with small grain size fractions. As a result life and growth conditions of the microorganisms are negatively affected. This leads to less biological activity, restricted degradation/mineralization of pollutants or altered microbial processes. The aim of conducted laboratory column experiments was to study the correlation between the grain size fractions respectively pore sizes, the oxygen content and the biodegradation rate of infiltrated organic substances. Therefore two columns (active + sterile control) were filled with different grain size fractions (0,063-0,125 mm, 0,2-0,63 mm and 1-2 mm) of soils. The sterile soil was inoculated with a defined amount of a special bacteria culture (sphingobium yanoikuae). A solution with organic substances glucose, oxalic acid, sinaphylic alcohol and nutrients was infiltrated from the top in intervals. The degradation of organic substances was controlled by the measurement of dissolved organic carbon in the in- and outflow of the column. The control of different pore volumes

  11. Ions in a binary asymmetric dipolar mixture: Mole fraction dependent Born energy of solvation and partial solvent polarization structure

    NASA Astrophysics Data System (ADS)

    Kashyap, Hemant K.; Biswas, Ranjit

    2007-11-01

    Mean spherical approximation (MSA) for electrolyte solution has been extended to investigate the role of partial solvent polarization densities around an ion in a completely asymmetric binary dipolar mixture. The differences in solvent diameters, dipole moments, and ionic size are incorporated systematically within the MSA framework in the present theory for the first time. In addition to the contributions due to difference in dipole moments, the solvent-solvent and ion-solvent size ratios are found to significantly affect the nonideality in binary dipolar mixtures. Subsequently, the theory is used to investigate the role of ion-solvent and solvent-solvent size ratios in determining the nonideality in Born free energy of solvation of a unipositive rigid ion in alcohol-water and dimethyl sulfoxide-acetonitrile mixtures, where the solvent components are represented only by their molecular diameters and dipole moments. Nonideality in Born free energy of solvation in such simplified mixtures is found to be stronger for smaller ions. The slope of the nonideality for smaller alkali metal ions in methanol-water mixture is found to be opposite to that for larger ion, such as quaternary tertiary butyl ammonium ion. For ethanol-water mixtures, the slopes are in the same direction for all the ions studied here. These results are in qualitative agreement with experiments, which is surprising as the present MSA approach does not include the hydrogen bonding and hydrophobic interactions present in the real mixtures. The calculated partial polarization densities around a unipositive ion also show the characteristic deviation from ideality and reveal the microscopic origin of the ion and solvent size dependent preferential solvation. Also, the excess free energy of mixing (in the absence of any ion) for these binary mixtures has been calculated and a good agreement between theory and experiment has been found.

  12. Deuterium isotope effect on the oxidation of monophenols and o-diphenols by tyrosinase.

    PubMed Central

    Fenoll, Lorena G; Peñalver, María José; Rodríguez-López, José N; García-Ruiz, P A; García-Cánovas, Francisco; Tudela, José

    2004-01-01

    A solvent deuterium isotope effect on the catalytic affinity (km) and catalytic constant (kcat) of tyrosinase in its action on different monophenols and o-diphenols was observed. The catalytic constant decreased in all substrates as the molar fraction of deuterated water in the medium increased, while the catalytic affinity only decreased for the o-diphenols with an R group in C-1 [-H, -CH3 and -CH(CH3)2]. In a proton inventory study of the oxidation of o-diphenols, the representation of kcat fn/kcat f0 against n (atom fractions of deuterium), where kcat fn is the catalytic constant for a molar fraction of deuterium (n) and kcat f0 is the corresponding kinetic parameter in a water solution, was linear for all substrates, indicating that only one of the four protons transferred from the hydroxy groups of the two molecules of substrate, which are oxidized in one turnover, is responsible for the isotope effects, the proton transferred from the hydroxy group of C-4 to the peroxide of the oxytyrosinase form (Eox). However, in the representation of Km fn/Km f0 against n, where Km fn represents the catalytic affinity for a molar fraction of deuterium (n) and Km f0 is the corresponding kinetic parameter in a water solution, a linear decrease was observed as n increased in the case of o-diphenols with the R group [-H, -CH3 and -CH(CH3)2], and a parabolic increase with other R groups, indicating that more than one proton is responsible for the isotope effects on substrate binding. In the case of monophenols with six protons transferred in the catalytic cycle, the isotope effect occurs in the same way as for o-diphenols. In the present paper, the fractionation factors of different monophenols and o-diphenols are described and possible mechanistic implications are discussed. PMID:15025557

  13. A novel technique to remove deuterium from CANDU pressure tubes

    NASA Astrophysics Data System (ADS)

    Qin, Z.; Zhang, C.-S.; Griffiths, K.; Norton, P. R.

    2001-10-01

    Deuterium ingress into the pressure tubes of a Canada deuterium uranium (CANDU) nuclear reactor can cause the pressure tubes to crack prematurely. A novel technique, based on the rapid diffusion of deuterium in zirconium alloys, and subsequent preferential segregation of deuterium at the surface, has been developed to remove dissolved deuterium. This technique involves a simple continuous plasma treatment of the surface of a pressure tube, and can remove as much as 70% of the dissolved deuterium from the entire wall thickness of a pressure tube in realistic time scales. The proposed technique has considerable economic incentive: it may extend the life of pressure tubes without channel replacement.

  14. Provocative Questions for the Deuterium Session

    NASA Astrophysics Data System (ADS)

    Linsky, Jeffrey L.

    2009-05-01

    Analyses of spectra obtained with the Far Ultraviolet Spectrograph Explorer (FUSE) satellite, together with spectra from the Copernicus, Hubble Space Telescope (HST), and Interstellar Medium Absorption Profile Spectrograph (IMAPS) instruments reveal a very wide range in the observed deuterium/hydrogen (D/H) ratios for interstellar gas in the Galactic disk beyond the Local Bubble. For gas located beyond the Local Bubble but within several hundred parsecs, the observed D/H ratios differ by a factor of 4-5. A critically important question is what value or values of D/H in the local region of our Galaxy should be compared with chemical evolution models of the Galaxy and with the primordial deuterium abundance. Linsky et al. [Astrophys. J. 647, 1106 (2006)] argued that spatial variations in the depletion of deuterium onto dust grains can explain these local variations in the observed gas-phase D/H ratios. In this provacative introduction to the deuterium session, I ask six questions concerning analysis techniques and proposed results from the FUSE D/H program in the hope that the speakers and participants in this conference will give serious thought to the robustness of our present understanding of this important topic. In particular, is the deuterium depletion model valid? Is it only part of the explanation?

  15. Immune-system-dependent anti-tumor activity of a plant-derived polyphenol rich fraction in a melanoma mouse model.

    PubMed

    Gomez-Cadena, A; Urueña, C; Prieto, K; Martinez-Usatorre, A; Donda, A; Barreto, A; Romero, P; Fiorentino, S

    2016-01-01

    Recent findings suggest that part of the anti-tumor effects of several chemotherapeutic agents require an intact immune system. This is in part due to the induction of immunogenic cell death. We have identified a gallotannin-rich fraction, obtained from Caesalpinia spinosa (P2Et) as an anti-tumor agent in both breast carcinoma and melanoma. Here, we report that P2Et treatment results in activation of caspase 3 and 9, mobilization of cytochrome c and externalization of annexin V in tumor cells, thus suggesting the induction of apoptosis. This was preceded by the onset of autophagy and the expression of immunogenic cell death markers. We further demonstrate that P2Et-treated tumor cells are highly immunogenic in vaccinated mice and induce immune system activation, clearly shown by the generation of interferon gamma (IFN-γ) producing tyrosine-related protein 2 antigen-specific CD8+ T cells. Moreover, the tumor protective effects of P2Et treatment were abolished in immunodeficient mice, and partially lost after CD4 and CD8 depletion, indicating that P2Et's anti-tumor activity is highly dependent on immune system and at least in part of T cells. Altogether, these results support the hypothesis that the gallotannin-rich fraction P2Et's anti-tumor effects are mediated to a great extent by the endogenous immune response following to the exposure to immunogenic dying tumor cells. PMID:27253407

  16. Effects of detergents on Na+ + K+-dependent ATPase activity in plasma-membrane fractions prepared from frog muscles. Studies of insulin action on Na+ and K+ transport.

    PubMed Central

    Omatsu-Kanbe, M; Kitasato, H

    1987-01-01

    The increase in Na+/K+ transport activity in skeletal muscles exposed to insulin was analysed. Plasma-membrane fractions were prepared from frog (Rana catesbeiana) skeletal muscles, and examination of the Na,K-ATPase (Na+ + K+-dependent ATPase) activity showed that it was insensitive to ouabain. In contrast, plasma-membrane fractions prepared from ouabain-pretreated muscles, by the same procedures, showed extremely low Na,K-ATPase activity. On adding saponin to the membrane suspension, the Na,K-ATPase activity increased, according to the detergent concentration. The maximum activity was about twice the control value, at 0.33 mg of saponin/mg of protein. Thus saponin makes vesicle membranes leaky, allowing ouabain in assay solutions to reach receptors on the inner surface of vesicles. Addition of insulin to saponin-treated membrane suspensions had no effect on the Na,K-ATPase activity, whereas the maximum activity of Na,K-ATPase in whole muscles was stimulated by exposure to insulin. The results show that the stimulation of Na+/K+ transport by insulin is not directly due to insulin binding to receptors on the cell surface, but rather support the view that the increase in the Na,K-ATPase induced by insulin requires an alteration of intracellular events. PMID:2825643

  17. Fundamental Equation of State for Deuterium

    SciTech Connect

    Richardson, I. A.; Leachman, J. W.; Lemmon, E. W.

    2014-03-15

    World utilization of deuterium is anticipated to increase with the rise of fusion-energy machines such as ITER and NIF. We present a new fundamental equation of state for the thermodynamic properties of fluid deuterium. Differences between thermodynamic properties of orthodeuterium, normal deuterium, and paradeuterium are described. Separate ideal-gas functions were fitted for these separable forms together with a single real-fluid residual function. The equation of state is valid from the melting line to a maximum pressure of 2000 MPa and an upper temperature limit of 600 K, corresponding to available experimental measurements. The uncertainty in predicted density is 0.5% over the valid temperature range and pressures up to 300 MPa. The uncertainties of vapor pressures and saturated liquid densities are 2% and 3%, respectively, while speed-of-sound values are accurate to within 1% in the liquid phase.

  18. Wafer Mapping Using Deuterium Enhanced Defect Characterization

    NASA Astrophysics Data System (ADS)

    Hossain, K.; Holland, O. W.; Hellmer, R.; Vanmil, B.; Bubulac, L. O.; Golding, T. D.

    2010-07-01

    Deuterium (as well as other hydrogen isotopes) binds with a wide range of morphological defects in semiconductors and, as such, becomes distributed similarly to those defects. Thus, the deuterium profile within the sample serves as the basis of a technique for defect mapping known as amethyst wafer mapping (AWM). The efficiency of this technique has been demonstrated by evaluation of ion-induced damage in implanted Si, as well as as-grown defects in HgCdTe (MCT) epilayers. The defect tagging or decoration capability of deuterium is largely material independent and applicable to a wide range of defect morphologies. A number of analytical techniques including ion channeling and etch pit density measurements were used to evaluate the AWM results.

  19. Deuterium-incorporated gate oxide of MOS devices fabricated by using deuterium ion implantation

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Sung; Lear, Kevin L.

    2012-04-01

    In the aspect of metal-oxide-semiconductor (MOS) device reliability, deuterium-incorporated gate oxide could be utilized to suppress the wear-out that is combined with oxide trap generation. An alternative deuterium process for the passivation of oxide traps or defects in the gate oxide of MOS devices has been suggested in this study. The deuterium ion is delivered to the location where the gate oxide resides by using an implantation process and subsequent N2 annealing process at the back-end of metallization process. A conventional MOS field-effect transistor (MOSFET) with a 3-nm-thick gate oxide and poly-to-ploy capacitor sandwiched with 20-nm-thick SiO2 were fabricated in order to demonstrate the deuterium effect in our process. An optimum condition of ion implantation was necessary to account for the topography of the overlaying layers in the device structure and to minimize the physical damage due to the energy of the implanted ion. Device parameter variations, the gate leakage current, and the dielectric breakdown phenomenon were investigated in the deuterium-ion-implanted devices. We found the isotope effect between hydrogen- and deuterium-implanted devices and an improved electrical reliability in the deuterated gate oxide. This implies that deuterium bonds are generated effectively at the Si/SiO2 interface and in the SiO2 bulk.

  20. Scaling and long-range dependence in option pricing I: Pricing European option with transaction costs under the fractional Black-Scholes model

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Tian

    2010-02-01

    This paper deals with the problem of discrete time option pricing by the fractional Black-Scholes model with transaction costs. By a mean self-financing delta-hedging argument in a discrete time setting, a European call option pricing formula is obtained. The minimal price C(t,St) of an option under transaction costs is obtained as timestep δt=((, which can be used as the actual price of an option. In fact, C(t,St) is an adjustment to the volatility in the Black-Scholes formula by using the modified volatility σ√{2}(( to replace the volatility σ, where {k}/{σ}<(, H>{1}/{2} is the Hurst exponent, and k is a proportional transaction cost parameter. In addition, we also show that timestep and long-range dependence have a significant impact on option pricing.

  1. Oxidation of C1 Compounds by Particulate fractions from Methylococcus capsulatus: distribution and properties of methane-dependent reduced nicotinamide adenine dinucleotide oxidase (methane hydroxylase).

    PubMed Central

    Ribbons, D W

    1975-01-01

    Cell-free particulate fractions of extracts from the obligate methylotroph Methylococcus capsulatus catalyze the reduced nicotinamide adenine dinucleotide (NADH) and O2-dependent oxidation of methane (methane hydroxylase). The only oxidation product detected was formate. These preparations also catalyze the oxidation of methanol and formaldehyde to formate in the presence or absence of phenazine methosulphate with oxygen as the terminal electron acceptor. Methane hydroxylase activity cannot be reproducibly obtained from disintegrated cell suspensions even though the whole cells actively respired when methane was presented as a substrate. Varying the disintegration method or extraction medium had no significant effect on the activities obtained. When active particles were obtained, hydroxylase activity was stable at 0 C for days. Methane hydroxylase assays were made by measuring the methane-dependent oxidation of NADH by O2. In separate experiments, methane consumption and the accumulation of formate were also demonstrated. Formate is not oxidized by these particulate fractions. The effects of particle concentration, temperature, pH, and phosphate concentration on enzymic activity are described. Ethane is utilized in the presence of NADH and O2. The stoichiometric relationships of the reaction(s) with methane as substrate were not established since (i) the presumed initial product, methanol, is also oxidized to formate, and (ii) the contribution that NADH oxidase activity makes to the observed consumption of reactants could not be assessed in the presence of methane. Studies with known inhibitors of electron transport systems indicate that the path of electron flow from NADH to oxygen is different for the NADH oxidase, methane hydroxylase, and methanol oxidase activities. Images PMID:238946

  2. Identical Hg isotope mass dependent fractionation signature during methylation by sulfate-reducing bacteria in sulfate and sulfate-free environment.

    PubMed

    Perrot, Vincent; Bridou, Romain; Pedrero, Zoyne; Guyoneaud, Remy; Monperrus, Mathilde; Amouroux, David

    2015-02-01

    Inorganic mercury (iHg) methylation in aquatic environments is the first step leading to monomethylmercury (MMHg) bioaccumulation in food webs and might play a role in the Hg isotopic composition measured in sediments and organisms. Methylation by sulfate reducing bacteria (SRB) under sulfate-reducing conditions is probably one of the most important sources of MMHg in natural aquatic environments, but its influence on natural Hg isotopic composition remains to be ascertained. In this context, the methylating SRB Desulfovibrio dechloracetivorans (strain BerOc1) was incubated under sulfate reducing and fumarate respiration conditions (SR and FR, respectively) to determine Hg species specific (MMHg and IHg) isotopic composition associated with methylation and demethylation kinetics. Our results clearly establish Hg isotope mass-dependent fractionation (MDF) during biotic methylation (-1.20 to +0.58‰ for δ(202)Hg), but insignificant mass-independent fractionation (MIF) (-0.12 to +0.15‰ for Δ(201)Hg). During the 24h of the time-course experiments Hg isotopic composition in the produced MMHg becomes significantly lighter than the residual IHg after 1.5h and shows similar δ(202)Hg values under both FR and SR conditions at the end of the experiments. This suggests a unique pathway responsible for the MDF of Hg isotopes during methylation by this strain regardless the metabolism of the cells. After 9 h of experiment, significant simultaneous demethylation is occurring in the culture and demethylates preferentially the lighter Hg isotopes of MMHg. Therefore, depending on their methylation/demethylation capacities, SRB communities in natural sulfate reducing conditions likely have a significant and specific influence on the Hg isotope composition of MMHg (MDF) in sediments and aquatic organisms. PMID:25564955

  3. Deuterium in crystalline and amorphous silicon

    SciTech Connect

    Borzi, R.; Ma, H.; Fedders, P.A.; Leopold, D.J.; Norberg, R.E.; Boyce, J.B.; Johnson, N.M.; Ready, S.E.; Walker, J.

    1997-07-01

    The authors report deuteron magnetic resonance (DMR) measurements on aged deuterium-implanted single crystal n-type silicon and comparisons with amorphous silicon spectra. The sample film was prepared six years ago by deuteration from a-D{sub 2} plasma and evaluated by a variety of experimental methods. Deuterium has been evolving with time and the present DMR signal shows a smaller deuteron population. A doublet from Si-D configurations along (111) has decreased more than have central molecular DMR components, which include 47 and 12 kHz FWHM gaussians. Transient DMR magnetization recoveries indicate spin lattice relaxation to para-D{sub 2} relaxation centers.

  4. Oxygen isotopes in synthetic goethite and a model for the apparent pH dependence of goethite-water 18O/ 16O fractionation

    NASA Astrophysics Data System (ADS)

    Yapp, Crayton J.

    2007-03-01

    Goethite synthesis experiments indicate that, in addition to temperature, pH can affect the measured value of the 18O/ 16O fractionation factor between goethite and water ( αG-W). A simple model was developed which expresses αG-W in terms of kinetic parameters associated with the growth of goethite from aqueous solution. The model predicts that, at a particular temperature, the range of pH over which αG-W changes as pH changes is expected to be comparatively small (˜3 pH "units") relative to the range of pH values over which goethite can crystallize (pH from ˜1 to 14). Outside the range of sensitivity to pH, αG-W is predicted to be effectively constant (for constant temperature) at either a low-pH αG-W value or a high-pH αG-W value. It also indicates that the values of αG-W at high pH will be disequilibrium values. Values of αG-W for goethite crystallized at low pH may approach, but probably do not attain, equilibrium values. For goethite synthesized at values of pH from ˜1 to 2, data from two different laboratories define the following equation for the temperature dependence of 1000 ln αG-W ( T in degrees Kelvin) 1000lnα={1.66×106}/{T2}-12.6 Over the range of temperatures from 0 to 120°C, values of 1000 ln αG-W from Eq. (IV) differ by ⩽0.1‰from those of a published equation [Yapp C.J., 1990. Oxygen isotopes in iron (III) oxides. 1. Mineral-water fractionation factors. Chem. Geol.85, 329-335]. Therefore, interpretations of data from natural goethites using the older equation are not changed by use of Eq. (IV). Data from a synthetic goethite suggest that the temperature dependence of 1000 ln αG-W at low pH as expressed in Eq. (IV) may be valid for values of pH up to at least 6. This result and the model prediction of an insensitivity of αG-W to pH over a larger range of pH values could explain the observation that Eq. (IV) yields values of αG-W which mimic most 18O/ 16O fractionations measured to date in natural goethites.

  5. Theoretical predictions of deuterium abundances in the Jovian planets

    SciTech Connect

    Hubbard, W.B.; MacFarlane, J.J.

    1980-01-01

    Current concepts for the origin of the Jovian planets and current constraints on their interior structure are used to support the argument that the presence of large amounts of 'ice' (H2O, CH4, and NH3) in Uranus and Neptune indicates temperature low enough to condense these species at the time Uranus and Neptune formed. Such low temperatures, however, imply orders-of-magnitude fractionation effects for deuterium into the 'ice' component if isotopic equilibration can occur. The present models thus imply that Uranus and Neptune should have D/H ratio at least four times primordial, contrary to observation for Uranus. It is found that the Jovian and Saturnian D/H should be close to primordial regardless of formation scenario.

  6. The predicted abundances of deuterium-bearing gases in the atmospheres of Jupiter and Saturn

    NASA Technical Reports Server (NTRS)

    Fegley, Bruce, Jr.; Prinn, Ronald G.

    1988-01-01

    The first set of comprehensive thermochemical equilibrium and chemical kinetic calculations on the chemistry of deuterium-bearing gases in the deep atmospheres of Jupiter and Saturn is presented. The sensitivity of the results to variations in elemental and isotopic abundances is studied. Isotopic fractionation effects in the C-13/C12, N-15/N-14, and O-18/O-16 ratios in nonequilibrium species such as CO, CO2, HCN, and N2 are briefly considered.

  7. Deuterium separation by infrared-induced addition reaction

    DOEpatents

    Marling, John B.

    1977-01-01

    A method for deuterium enrichment by the infrared-induced addition reaction of a deuterium halide with an unsaturated aliphatic compound. A gaseous mixture of a hydrogen halide feedstock and an unsaturated aliphatic compound, particularly an olefin, is irradiated to selectively vibrationally excite the deuterium halide contained therein. The excited deuterium halide preferentially reacts with the unsaturated aliphatic compound to produce a deuterated addition product which is removed from the reaction mixture.

  8. New Analysis of Hydrogen and Deuterium Escape from Venus

    NASA Astrophysics Data System (ADS)

    Donahue, Thomas M.

    1999-10-01

    This paper is concerned with the time required for escape of hydrogen and deuterium to produce the present D/ H ratio in Venus water, the sizes of the original hydrogen reservoirs and their sensitivity to the magnitude of the present escape fluxes, the characteristics of exogenous and endogenous hydrogen sources, and the D/ H ratio for primordial Venus hydrogen. The procedure followed allowed the H escape flux to vary over a large range, the ratio of input to escape flux to vary from 0 to 1, and the fractionation factor, which expresses the relative efficiency of D and H escape, to vary between 0.02 and 0.5. It was found that, unless deuterium escape is very efficient, the present H escape flux (averaged over a solar cycle) cannot be larger than about 10 7 cm -2 s -1 if today's water is to be the remnant of water deposited eons ago. On the other hand if the escape flux is as large as large as 3×10 7 cm -2 s -1, today's water would be the remnant of water outgassed only about 500 million years ago. These conclusions are relatively insensitive to factors other than the magnitude of the escape flux. Since recent analysis of escape fluxes indicates that the H escape fluxes may be in the neighborhood of 3×10 7 cm -2 s -1 and the fractionation factor may be 0.14 or larger, the suggestion of Grinspoon (1993, Nature 363, 1702-1704) that the water now on Venus was created during a recent massive resurfacing event is credible. However, since it is still possible that the average escape flux is as small as 7×10 6 cm -2 s -1, the choice between 4 and 0.5 Gyr must await a resolution of this conflict by reanalysis of Pioneer Venus Lyman α data (Paxton, L., D. E. Anderson, and A. I. F. Stewart 1988, J. Geophys. Res. 93, 1766-1772).

  9. Reactions of vibrationally excited deuterium molecules with H and D atoms

    SciTech Connect

    Gershenzon, Yu.M.; Ivanov, A.V.; Rozenshtein, V.B.; Umanskii, S.Ya.

    1988-03-01

    An EPR spectrometer is used to study the reactions of vibrationally excited deuterium molecules with hydrogen and deuterium atoms. For the first time selective measurements are made of the separate channels for reactions of vibrationally excited D/sub 2/ molecules with H atoms and their temperatures dependence is studied over the interval from 298 to 367 K. An estimate of the total rate constant for loss of a vibrational quantum in the reaction D + D/sub 2/ (v = 1) at 300 K is obtained. The measurements are in good agreement with dynamic calculations.

  10. Recombination-induced athermal migration of hydrogen and deuterium in SiC

    SciTech Connect

    Koshka, Yaroslav; Krishnan, Bharat

    2005-02-01

    The phenomenon of recombination-induced formation of hydrogen-defect complexes in epitaxial silicon carbide (SiC) was further investigated on p-type samples treated in deuterium plasma. Qualitatively similar effects were observed for hydrogen and deuterium. The formation of hydrogen-related (deuterium-related) defects would depend on the temperature of the sample during plasma treatment, with lower process temperatures causing only incorporation of hydrogen (deuterium) near the surface without any significant formation of electrically or optically active hydrogen-related or deuterium-related defects in the epilayer. Higher process temperatures normally produced more efficient formation of new centers, including passivation of acceptors in SiC. In all cases, prolonged excitation of the hydrogenated (deuterated) samples with above-bandgap light at reduced temperatures caused recombination-induced formation of a few different defect centers. A confirmation of the long-range athermal migration of hydrogen from the surface into the bulk of the sample was obtained. It has been established that it is the recombination-induced migration of hydrogen that is responsible for the formation of hydrogen-related defect centers under optical excitation.

  11. D/H Fractionation in the Atmosphere-Ground Ice System on Mars

    NASA Astrophysics Data System (ADS)

    Ellehøj, M. D.; Johnsen, S. J.; Madsen, M. B.

    2009-03-01

    The solid-vapor fractionation processes of Deuterium/Hydrogen (D/H) in the ground ice-atmosphere system on Mars are investigated through experiments and modeling. Preliminary results mainly from the experimental work are presented.

  12. Comparison between the radial density buildup in the TARA plugs using hydrogen versus deuterium neutral beams

    SciTech Connect

    Blackfield, D.T.

    1983-11-01

    The WOLF code is used to compare the beam divergences from a TARA source using hydrogen and deuterium. Factors which influence the divergence which are investigated are the electron temperature, initial ion energy, electrode positions and ion beam current density. The beam divergence for 20 keV hydrogen is found to be only 20% smaller than for 25 keV deuterium for the same electrode positions. Since the optimal positioning of the electrodes is found to be independent of mesh spacing, a large parameter study is undertaken using little computer time. A time-dependent radial Fokker-Planck code is next used to examine the radial density buildup in a plug of the TARA tandem mirror. For both hydrogen and deuterium neutral beams, the influences of beam positioning, current and energy, edge neutral pressure and assumed electron temperature are studied.

  13. Fractionally charged Wilson loops as a probe of {theta} dependence in CP{sup N-1} sigma models: Instantons versus large N

    SciTech Connect

    Keith-Hynes, Patrick; Thacker, H. B.

    2008-07-15

    The behavior of Wilson loops with fractional charge is used to study the {theta} dependence of the free energy density {epsilon}({theta}) for the CP{sup 1}, CP{sup 5}, and CP{sup 9} sigma models in two space-time dimensions. The function {epsilon}({theta}) is extracted from the area law for a Wilson loop of charge q={theta}/2{pi}. For CP{sup 1}, {epsilon}({theta}) is smooth in the region {theta}{approx_equal}{pi} and well described by a dilute instanton gas throughout the range 0<{theta}<2{pi}. For CP{sup 5} and CP{sup 9} the energy exhibits a clear cusp and evidence for discrete, degenerate vacua at {theta}={pi}, as expected from large N arguments. For CP{sup 9} the {theta} dependence is in good quantitative agreement with the leading-order large N prediction {epsilon}({theta})=(1/2){chi}{sub t}{theta}{sup 2} throughout the range 0<{theta}<{pi}.

  14. RF physics in Deuterium-Tritium plasmas

    SciTech Connect

    Phillips, C. K.; Bell, M.; Bell, R. E.; Bernabei, S.; Fredrickson, E.; Hosea, J. C.; LeBlanc, B. P.; Majeski, R.; Medley, S.; Ono, M.

    1999-09-20

    A wide variety of potential ICRF heating scenarios relevant for the deuterium-tritium plasmas expected in tokamak reactor-class devices were explored in the TFTR and JET programs. Key physics results from the two programs are discussed. (c) 1999 American Institute of Physics.

  15. Synthesis of deuterium-labeled prochlorperazine

    SciTech Connect

    Hawes, E.M.; Gurnsey, T.S.; Shetty, H.U.; Midha, K.K.

    1983-06-01

    The propylpiperazine side chain of prochlorperazine was labeled with two, four, or six deuterium atoms by lithium aluminum deuteride reduction of the appropriate amide. The isotopic purity of the products after correcting for chlorine isotopes was greater than 95.7%.

  16. The primordial abundance of deuterium: ionization correction

    NASA Astrophysics Data System (ADS)

    Cooke, Ryan; Pettini, Max

    2016-01-01

    We determine the relative ionization of deuterium and hydrogen in low metallicity damped Lyman α (DLA) and sub-DLA systems using a detailed suite of photoionization simulations. We model metal-poor DLAs as clouds of gas in pressure equilibrium with a host dark matter halo, exposed to the Haardt & Madau background radiation of galaxies and quasars at redshift z ≃ 3. Our results indicate that the deuterium ionization correction correlates with the H I column density and the ratio of successive ion stages of the most commonly observed metals. The N(N II)/N(N I) column density ratio provides the most reliable correction factor, being essentially independent of the gas geometry, H I column density, and the radiation field. We provide a series of convenient fitting formulae to calculate the deuterium ionization correction based on observable quantities. The ionization correction typically does not exceed 0.1 per cent for metal-poor DLAs, which is comfortably below the current measurement precision (2 per cent). However, the deuterium ionization correction may need to be applied when a larger sample of D/H measurements becomes available.

  17. The deuterium puzzle in the symmetric universe

    NASA Technical Reports Server (NTRS)

    Leroy, B.; Nicolle, J. P.; Schatzman, E.

    1973-01-01

    An attempt was made to use deuterium abundance in the symmetric universe to prove that no nucleosynthesis takes place during annihilation and therefore neutrons were loss before nucleosynthesis. Data cover nucleosynthesis during the radiative era, cross section estimates, maximum abundance of He-4 at the end of nucleosynthesis area, and loss rate.

  18. Permeation of deuterium implanted into vanadium alloys

    SciTech Connect

    Anderl, R.A.; Longhurst, G.R.; Struttmann, D.A.

    1986-05-01

    Permeation of deuterium through the vanadium alloy, V-15Cr-5Ti, was investigated using 3-keV, D/sub 3//sup +/ ion beams from a small accelerator. The experiments consisted of measurements of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5-mm thick specimens heated to tempertures from 623 to 823/sup 0/K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). Analyses of these measurements indicate that for the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This corresponds to approximately 1000 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates D = 1.4 x 10/sup -8/ exp(-.11 eV/kT) (m/sup 2//s).

  19. Thermotransport of hydrogen and deuterium in vanadium-niobium, vanadium-titanium, and vanadium-chromium alloys

    NASA Astrophysics Data System (ADS)

    Peterson, D. T.; Smith, M. F.

    1983-04-01

    Thermotransport of hydrogen and deuterium in vanadium alloyed with either niobium, titanium, or chromium is much greater than in pure vanadium, and additions of vanadium to niobium similarly increase thermotransport of hydrogen and deuterium over that observed in pure niobium. In all cases, the heat of transport was positive and was significantly greater for deuterium than for hydrogen. The results are consistent with an atomistic model in which the temperature dependence of atomic jump frequencies is the dominant factor in thermotransport with a small bias in the direction of atomic jumps. There is evidence that differences between the heats of transport for hydrogen and deuterium may be related to isotope effects in the activation energies for diffusion.

  20. Fractionation of oil sands-process affected water using pH-dependent extractions: a study of dissociation constants for naphthenic acids species.

    PubMed

    Huang, Rongfu; Sun, Nian; Chelme-Ayala, Pamela; McPhedran, Kerry N; Changalov, Mohamed; Gamal El-Din, Mohamed

    2015-05-01

    The fractionation of oil sands process-affected water (OSPW) via pH-dependent extractions was performed to quantitatively investigate naphthenic acids (NAs, CnH2n+ZO2) and oxidized NAs (Ox-NAs) species (CnH2n+ZO3 and CnH2n+ZO4) using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOFMS). A mathematical model was also developed to estimate the dissociation constant pKa for NAs species, considering the liquid-liquid extraction process and the aqueous layer acid-base equilibrium. This model provides estimated dissociation constants for compounds in water samples based on fractionation extraction and relative quantification. Overall, the sum of O2-, O3-, and O4-NAs species accounted for 33.6% of total extracted organic matter. Accumulative extracted masses at different pHs revealed that every oxygen atom added to NAs increases the pKa (i.e., O2-NAs

  1. Hydrogen-deuterium substitution in solid ethanol by surface reactions at low temperatures

    NASA Astrophysics Data System (ADS)

    Oba, Yasuhiro; Osaka, Kazuya; Chigai, Takeshi; Kouchi, Akira; Watanabe, Naoki

    2016-10-01

    Ethanol (CH3CH2OH) is one of the most abundant complex organic molecules in star-forming regions. Despite its detection in the gas phase only, ethanol is believed to be formed by low-temperature grain-surface reactions. Methanol, the simplest alcohol, has been a target for observational, experimental, and theoretical studies in view of its deuterium enrichment in the interstellar medium; however, the deuterium chemistry of ethanol has not yet been an area of focus. Recently, deuterated dimethyl ether, a structural isomer of ethanol, was found in star-forming regions, indicating that deuterated ethanol can also be present in those environments. In this study, we performed laboratory experiments on the deuterium fractionation of solid ethanol at low temperatures through a reaction with deuterium (D) atoms at 10 K. Hydrogen (H)-D substitution, which increases the deuteration level, was found to occur on the ethyl group but not on the hydroxyl group. In addition, when deuterated ethanol (e.g. CD3CD2OD) solid was exposed to H atoms at 10 K, D-H substitution that reduced the deuteration level occurred on the ethyl group. Based on the results, it is likely that deuterated ethanol is present even under H-atom-dominant conditions in the interstellar medium.

  2. Pressure Dependent Mass Fraction in Noble Gas Mass Spectrometers: A Possible Explanation for the Excessive Dispersion in the EARTHTIME Fish Canyon/Alder Creek Inter-Calibration Experiment

    NASA Astrophysics Data System (ADS)

    Turrin, B. D.; Swisher, C. C.; Mana, S.

    2011-12-01

    Mass spectrometer fractionation bias (mass discrimination) is a ubiquitous phenomenon in noble gas mass spectroscopy and must be corrected for in order to obtain accurate-high precision isotopic ratios that are used in isotopic age calculations. Temporal variations in mass fractionation are well known phenomena and have been reported in several studies (eg. Turrin et al., 2010 and references therein). Here we report on the pressure dependency on mass spectrometer fractionation bias. In our experiment, we varied by a factor of five the signal size of aliquots of atmospheric argon delivered from an automated air pipette system. The measured mass discrimination difference (MD) as determined by the 40Ar/36Ar ratio between the 1-fold and 5-fold air pipette shots is ~5%. The air 40Ar/36Ar aliquots were measured using a MAP 215-50 operating in pulse counting mode. The air measurements were interspersed with measurements of Alder Creek (AC) sanidine and Fish Canyon (FC) sanidine that were co-irradiated for 0.75 hours. The grain sizes for the two mineral standards were chosen such that the AC sample yielded 40Ar signals of about 50 kcps, similar to that delivered by a single aliquot delivered by the air pipette. The FC grains were about 5-10 times greater (150-600 kcps) than the single air aliquot. Following the analyses, we applied the MD correction to both the FC and AC analyses. When the MD as determined from the single pipette data (which matches 40Ar beam intensity of the AC sample) is applied to both the AC and FC data a "J" of 1.579±0.001x10-4 is obtained from the FC data and an age of 1183 ±4 ka for AC. However, when the MD as determined from the multiple aliquot pipette data (with an 40Ar beam similar to that of the FC analyses) is applied to the FC data a "J" of 1.588±0.001x10-4 is obtained and an AC age of 1189 ±4 ka the same age at the 95% confidence level, the reported age for AC. We conclude that variation in MD over signal sizes typically analyzed in 40Ar

  3. Deuterium stable isotope ratios as tracers of water resource use: an experimental test with rock doves.

    PubMed

    McKechnie, Andrew E; Wolf, Blair O; Martínez del Rio, Carlos

    2004-07-01

    Naturally-occurring deuterium stable isotope ratios can potentially be used to trace water resource use by animals, but estimating the contribution of isotopically distinct water sources requires the accurate prediction of isotopic discrimination factors between water inputs and an animal's body water pool. We examined the feasibility of using estimates of water fluxes between a bird and its environment with a mass-balance model for the deuterium stable isotope ratio of avian body water (deltaDbody) to predict isotopic discrimination factors. Apparent fractionation and thus discrimination factors were predicted to vary with the proportion of an animal's total water losses than could be attributed to evaporative processes. To test our ability to predict isotopic discrimination, we manipulated water intake and evaporative water loss in rock doves (Columba livia) by providing them with fresh water or 0.15 M NaCl solution in thermoneutral or hot environments. After we switched the birds from drinking water with deltaD=-95 per thousand VSMOW (Vienna Standard Mean Ocean Water) to enriched drinking water with deltaD=+52 per thousand VSMOW, steady-state deltaDbody was approached asymptotically. The equilibrium deltaDbody was enriched by 10-50 per thousand relative to water inputs. After isotopic equilibrium was reached, the degree of enrichment was positively related (r2=0.34) to the fraction of total water loss that occurred by evaporation (revap/rH2O)supporting the major prediction of the model. The variation we observed in discrimination factors suggests that the apparent fractionation of deuterium will be difficult to predict accurately under natural conditions. Our results show that accurate estimates of the contribution of different water sources to a bird's body water pool require large deuterium isotopic differences between the sources. PMID:15185137

  4. Deuterium motion in yttrium studied by ultrasonic measurements

    SciTech Connect

    Leisure, R.G. ); Schwarz, R.B.; Migliori, A. ); Torgeson, D.R. ); Svare, I. ); Anderson, I.S. )

    1993-07-01

    Ultrasonic-attenuation measurements in YD[sub 0.10] reveal broad, asymmetric attenuation peaks that are interpreted in terms of rapid motion of deuterium among interstitial sites in the Y metal lattice. The results are well described with a model involving tunneling among highly asymmetric sites. A weakly temperature-dependent relaxation rate, compatible with coupling of the sites to electrons, accounts for the relaxation up to about 70 K. At higher temperatures a strongly temperature-dependent relaxation rate becomes dominant. The major asymmetries that are responsible for the coupling of the tunneling centers to the ultrasound are attributed to the interaction between D atoms that lie on [ital different] [ital c] axes.

  5. A laser-driven source of polarized hydrogen and deuterium

    SciTech Connect

    Young, L.; Holt, R.J.; Gilman, R.A.; Kowalczyk, R.; Coulter, K.

    1989-01-01

    A novel laser-driven polarized source of hydrogen and deuterium which operates on the principle of spin-exchange optical pumping is being developed. This source is designed to operate as an internal target in an electron storage ring for fundamental studies of spin-dependent structure of nuclei. It has the potential to exceed the flux from existing conventional sources (3 /times/ 10/sup 16//s) by an order of magnitude. Currently, the source delivers hydrogen at a flux of 8 /times/ 10/sup 16/ atoms/s with an atomic polarization of 24% and deuterium at 6 /times/ 10/sup 16/ atoms/s with a polarization of 29%. Technical obstacles which have been overcome, with varying degrees of success are complete Doppler-coverage in the optical-pumping stage without the use of a buffer gas, wall-induced depolarization and radiation-trapping. Future improvements should allow achievement of the design goals of 4 /times/ 10/sup 17/ atoms/s with a polarization of 50%. 8 refs., 2 figs.

  6. Cosmic Deuterium and Social Networking Software

    NASA Astrophysics Data System (ADS)

    Pasachoff, J. M.; Suer, T.-A.; Lubowich, D. A.; Glaisyer, T.

    2006-08-01

    For the education of newcomers to a scientific field and for the convenience of students and workers in the field, it is helpful to have all the basic scientific papers gathered. For the study of deuterium in the Universe, in 2004-5 we set up http://www.cosmicdeuterium.info with clickable links to all the historic and basic papers in the field and to many of the current papers. Cosmic deuterium is especially important because all deuterium in the Universe was formed in the epoch of nucleosynthesis in the first 1000 seconds after the Big Bang, so study of its relative abundance (D:H~1:100,000) gives us information about those first minutes of the Universe's life. Thus the understanding of cosmic deuterium is one of the pillars of modern cosmology, joining the cosmic expansion, the 3 degree cosmic background radiation, and the ripples in that background radiation. Studies of deuterium are also important for understanding Galactic chemical evolution, astrochemistry, interstellar processes, and planetary formation. Some papers had to be scanned while others are available at the Astrophysical Data System, adswww.harvard.edu, or to publishers' Websites. By 2006, social networking software (http:tinyurl.com/ zx5hk) had advanced with popular sites like facebook.com and MySpace.com; the Astrophysical Data System had even set up MyADS. Social tagging software sites like http://del.icio.us have made it easy to share sets of links to papers already available online. We have set up http://del.icio.us/deuterium to provide links to many of the papers on cosmicdeuterium.info, furthering previous del.icio.us work on /eclipses and /plutocharon. It is easy for the site owner to add links to a del.icio.us site; it takes merely clicking on a button on the browser screen once the site is opened and the desired link is viewed in a browser. Categorizing different topics by keywords allows subsets to be easily displayed. The opportunity to expose knowledge and build an ecosystem of web

  7. Measurement of the Branching Fraction and Time-Dependent CP Asymmetry in the Decay B0 to D*+D*-Ks

    SciTech Connect

    Aubert, B.

    2006-09-26

    The authors study the decay B{sup 0} {yields} D*{sup +}D*{sup -} K{sub S}{sup 0} using (230 {+-} 2) x 10{sup 6} B{bar B} pairs collected by the BABAR detector at the PEP-II B factory. They measure a branching fraction {Beta}(B{sup 0} {yields} D*{sup +}D*{sup -} K{sub S}{sup 0}) = (4.4 {+-} 0.4 {+-} 0.7) x 10{sup -3} and find evidence for the decay B{sup 0} {yields} D*{sup -} D{sub s1}{sup +}(2536) with a statistical significance of 4.6 {sigma}. A time-dependent CP asymmetry analysis is also performed to study the possible resonant contributions to B{sup 0} {yields} D*{sup +}D*{sup -} K{sub S}{sup 0} and the sign of cos2{beta}. Their measurement indicates that there is a sizable resonant contribution to the decay B{sup 0} {yields} D*{sup +} D*{sup -} K{sub S}{sup 0} from a unknown D{sub s1}{sup +} state with large width, and that cos2{beta} is positive at the 94% confidence level under certain theoretical assumptions.

  8. N2 Mole Fraction Dependence of Plasma Bullet Propagation in Premixed He/N2 Plasma Needle Discharge at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Ni, Gengsong; Qian, Muyang; Yang, Congying; Liu, Sanqiu; Wang, Dezhen

    2016-07-01

    In this work, a computational modeling study on the mechanism of the acceleration behavior of a plasma bullet in needle-plane configuration is presented. Above all, in our model, two sub-models of time-dependent plasma dynamics and laminar flow are connected using a oneway coupled method, and both the working gas and the surrounding gas around the plasma jet are assumed to be the same, which are premixed He/N2 gas. The mole fractions of the N2 (NMF) ingredient are set to be 0.01%, 0.1% and 1% in three cases, respectively. It is found that in each case, the plasma bullet accelerates with time to a peak velocity after it exits the nozzle and then decreases until getting to the treated surface, and that the velocity of the plasma bullet increases at each time moment with the peak value changing from 0.72×106 m/s to 0.80×106 m/s but then drops more sharply when the NMF varies from 0.01% to 1%. Besides, the electron impact ionizations of helium neutrals and nitrogen molecules are found to have key influences on the propagation of a plasma bullet instead of the penning ionization. supported by National Natural Science Foundation of China (No. 11465013), the Natural Science Foundation of Jiangxi Province, China (No. 20151BAB212012), and in part by the International Science and Technology Cooperation Program of China (No. 2015DFA61800)

  9. Precision measures of the primordial abundance of deuterium

    SciTech Connect

    Cooke, Ryan J.; Jorgenson, Regina A.; Murphy, Michael T.; Steidel, Charles C.

    2014-01-20

    We report the discovery of deuterium absorption in the very metal-poor ([Fe/H] = –2.88) damped Lyα system at z {sub abs} = 3.06726 toward the QSO SDSS J1358+6522. On the basis of 13 resolved D I absorption lines and the damping wings of the H I Lyα transition, we have obtained a new, precise measure of the primordial abundance of deuterium. Furthermore, to bolster the present statistics of precision D/H measures, we have reanalyzed all of the known deuterium absorption-line systems that satisfy a set of strict criteria. We have adopted a blind analysis strategy (to remove human bias) and developed a software package that is specifically designed for precision D/H abundance measurements. For this reanalyzed sample of systems, we obtain a weighted mean of (D/H){sub p} = (2.53 ± 0.04) × 10{sup –5}, corresponding to a universal baryon density 100 Ω{sub b,} {sub 0} h {sup 2} = 2.202 ± 0.046 for the standard model of big bang nucleosynthesis (BBN). By combining our measure of (D/H){sub p} with observations of the cosmic microwave background (CMB), we derive the effective number of light fermion species, N {sub eff} = 3.28 ± 0.28. We therefore rule out the existence of an additional (sterile) neutrino (i.e., N {sub eff} = 4.046) at 99.3% confidence (2.7σ), provided that the values of N {sub eff} and of the baryon-to-photon ratio (η{sub 10}) did not change between BBN and recombination. We also place a strong bound on the neutrino degeneracy parameter, independent of the {sup 4}He primordial mass fraction, Y {sub P}: ξ{sub D} = +0.05 ± 0.13 based only on the CMB+(D/H){sub p} observations. Combining this value of ξ{sub D} with the current best literature measure of Y {sub P}, we find a 2σ upper bound on the neutrino degeneracy parameter, |ξ| ≤ +0.062.

  10. Precision Measures of the Primordial Abundance of Deuterium

    NASA Astrophysics Data System (ADS)

    Cooke, Ryan J.; Pettini, Max; Jorgenson, Regina A.; Murphy, Michael T.; Steidel, Charles C.

    2014-01-01

    We report the discovery of deuterium absorption in the very metal-poor ([Fe/H] = -2.88) damped Lyα system at z abs = 3.06726 toward the QSO SDSS J1358+6522. On the basis of 13 resolved D I absorption lines and the damping wings of the H I Lyα transition, we have obtained a new, precise measure of the primordial abundance of deuterium. Furthermore, to bolster the present statistics of precision D/H measures, we have reanalyzed all of the known deuterium absorption-line systems that satisfy a set of strict criteria. We have adopted a blind analysis strategy (to remove human bias) and developed a software package that is specifically designed for precision D/H abundance measurements. For this reanalyzed sample of systems, we obtain a weighted mean of (D/H)p = (2.53 ± 0.04) × 10-5, corresponding to a universal baryon density 100 Ωb, 0 h 2 = 2.202 ± 0.046 for the standard model of big bang nucleosynthesis (BBN). By combining our measure of (D/H)p with observations of the cosmic microwave background (CMB), we derive the effective number of light fermion species, N eff = 3.28 ± 0.28. We therefore rule out the existence of an additional (sterile) neutrino (i.e., N eff = 4.046) at 99.3% confidence (2.7σ), provided that the values of N eff and of the baryon-to-photon ratio (η10) did not change between BBN and recombination. We also place a strong bound on the neutrino degeneracy parameter, independent of the 4He primordial mass fraction, Y P: ξD = +0.05 ± 0.13 based only on the CMB+(D/H)p observations. Combining this value of ξD with the current best literature measure of Y P, we find a 2σ upper bound on the neutrino degeneracy parameter, |ξ| <= +0.062. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (VLT program IDs: 68.B-0115(A), 70.A-0425(C), 078.A-0185(A), 085.A-0109(A)), and at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of

  11. Deuterium Retention in NSTX with Lithium Conditioning

    SciTech Connect

    C.H. Skinner, J.P. Allain, W. Blanchard, H.W. Kugel, R. Maingi, L. Roquemore, V. Soukhanovskii, C.N. Taylor

    2010-06-02

    High (≈ 90%) deuterium retention was observed in NSTX gas balance measurements both withand without lithiumization of the carbon plasma facing components. The gas retained in ohmic discharges was measured by comparing the vessel pressure rise after a discharge to that of a gasonly pulse with the pumping valves closed. For neutral beam heated discharges the gas input and gas pumped by the NB cryopanels were tracked. The discharges were followed by outgassing of deuterium that reduced the retention. The relationship between retention and surface chemistry was explored with a new plasma-material interface probe connected to an in-vacuo surface science station that exposed four material samples to the plasma. XPS and TDS analysis showed that the binding of D atoms is fundamentally changed by lithium - in particular atoms are weakly bonded in regions near lithium atoms bound to either oxygen or the carbon matrix.

  12. Deuterium content of the Venus atmosphere

    NASA Technical Reports Server (NTRS)

    Bertaux, Jean-Loup; Clarke, John T.

    1989-01-01

    The abundance of deuterium in the atmosphere of Venus is an important clue to the role of water in the planet's history, because ordinary and deuterated water escape the atmosphere at different rates. The high-resolution mode of the IUE was used to measure hydrogen Lyman-alpha emission from Venus, but only an upper limit on deuterium Lyman-alpha emission was found, from which was inferred a D/H ratio of less than 0.002-0.005. This is smaller by a factor of 3-8 than the D/H ratio derived from measurements by the Pioneer Venus Large Probe, and may indicate either a stratification of D/H ratio with altitude or a smaller overall ratio than previously thought.

  13. Deuterium Abundance in the Local Interstellar Medium

    NASA Technical Reports Server (NTRS)

    Ferlet, R.; Gry, C.; Vidal-Madjar, A.

    1984-01-01

    The present situation of deuterium abundance evaluation in interstellar space is discussed, and it is shown that it should be or = .00001 by studying in more detail lambda the Sco line of sight and by observing two NaI interstellar components toward that star, it can be shown that the D/H evaluation made toward lambda Sco is in fact related to the local interstellar medium (less than 10 pc from the Sun). Because this evaluation is also or = .00001 it is in striking contrast with the one made toward alpha Aur (D/H or = .000018 confirming the fact that the deuterium abundance in the local interstellar medium varies by at least a factor of two over few parsecs.

  14. The size-dependent charge fraction of sub-3-nm particles as a key diagnostic of competitive nucleation mechanisms under atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Yu, F.; Turco, R.

    2011-04-01

    A clear physical understanding of atmospheric particle nucleation mechanisms is critical in assessing the influences of aerosols on climate and climate variability. Currently, several mechanisms have been proposed and are being employed to interpret field observations of nucleation events. Roughly speaking, the two most likely candidates are neutral cluster nucleation (NCN) and ion-mediated nucleation (IMN). Detailed nucleation event data has been obtained in boreal forests. In one set of analyses of these measurements, NCN was suggested as the dominant formation mode, while in another, it was IMN. Obviously, information on the electrical charge distribution carried by the nucleating clusters themselves is the key to identifying the relative contributions of neutral and ion-mediated processes under various conditions. Fortunately, ground-breaking measurements of the charged states or fractions of ambient nanometer-sized particles soon after undergoing nucleation are now available to help resolve the main pathway. In the present study, the size-dependent "apparent" formation rates and fractions of charged and neutral particles are simulated with a detailed kinetic model. We show that the predicted "apparent" formation rates of charged and neutral particles at 2 nm agree well with the corresponding values derived from the boreal forest data, but the "apparent" contribution of ion-based nucleation increases by up to ~ one order of magnitude as the size of particles decreases from 2 nm to ~1.5 nm. It appears that most of the neutral particles detected at sizes around 2 nm are in reality initially formed on ionic cores that are neutralized before the particles grow to this size. Thus, although the apparent rate of formation of neutral 2-nm particles might seem to be dominated by a neutral clustering process, in fact those particles are largely the result of an ion-induced nucleation mechanism. This point is clarified when the formation rates of smaller particles (e

  15. The size-dependent charge fraction of sub-3-nm particles as a key diagnostic of competitive nucleation mechanisms under atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Yu, F.; Turco, R. P.

    2011-09-01

    A clear physical understanding of atmospheric particle nucleation mechanisms is critical in assessing the influences of aerosols on climate and climate variability. Currently, several mechanisms have been proposed and are being employed to interpret field observations of nucleation events. Roughly speaking, the two most likely candidates are neutral cluster nucleation (NCN) and ion-mediated nucleation (IMN). Detailed nucleation event data has been obtained in boreal forests. In one set of analyses of these measurements, NCN was suggested as the dominant formation mode, while in another, it was IMN. Information on the electrical charge distribution carried by the nucleating clusters is one key for identifying the relative contributions of neutral and ion-mediated processes under various conditions. Fortunately, ground-breaking measurements of the charged states or fractions of ambient nanometer-sized particles soon after undergoing nucleation are now available to help resolve the main pathways. In the present study, the size-dependent "apparent" formation rates and fractions of charged and neutral particles in a boreal forest setting are simulated with a detailed kinetic model. We show that the predicted "apparent" formation rates of charged and neutral particles at 2 nm for eight representative case study days agree well with the corresponding values based on observations. In the simulations, the "apparent" contribution of ion-based nucleation increases by up to ~one order of magnitude as the size of "sampled" particles is decreased from 2 nm to ~1.5 nm. These results suggest that most of the neutral particles sampled in the field at sizes around 2 nm are in reality initially formed on ionic cores that are neutralized before the particles grow to this size. Thus, although the apparent rate of formation of neutral 2-nm particles might seem to be dominated by a neutral clustering process, in fact those particles may be largely the result of an ion-induced nucleation

  16. In vivo measurement of plasma cholesterol and fatty acid synthesis with deuterated water: determination of the average number of deuterium atoms incorporated.

    PubMed

    Diraison, F; Pachiaudi, C; Beylot, M

    1996-07-01

    Fractional lipid synthesis can be measured using the incorporation of deuterium from deuterated water. The calculations require knowledge of the maximum incorporation number (N) of deuterium atoms in the molecules synthesized. For both tissue palmitate and cholesterol, N values have been found to be higher during in vivo versus in vitro experiments. We determined the N values to be used for measuring the fractional synthesis of plasma cholesterol and of palmitate triglycerides (TG). Rats were given drinking water enriched (7% to 10%) with deuterated water, and N was determined from the mass isotopomer distributions of plasma cholesterol and plasma TG palmitate and the deuterium enrichment of plasma water. We found N to be 21 for palmitate and 27 for cholesterol. These values agree with those reported for tissue palmitate and cholesterol in vivo, and are higher than values found in vitro. We also found large deuterium enrichments in plasma glucose and in liver lactate and pyruvate. We suggest that, compared with in vitro studies, in vivo metabolism of these compounds leads to an additional pathway of incorporation of deuterium into lipids through deuterium-labeled acetyl coenzyme A (CoA). This could explain why N values are higher in vivo than in vitro. PMID:8692014

  17. Formation and retention of organically bound deuterium in rice in deuterium water release experiment.

    PubMed

    Atarashi-Andoh, Mariko; Amano, Hikaru; Kakiuchi, Hideki; Ichimasa, Michiko; Ichimasa, Yusuke

    2002-06-01

    As a substitute of tritium, deuterated water (D2O) vapor release experiments were performed in a greenhouse to estimate the different formation and subsequent retention of organically bound deuterium in rice plants between daytime and nighttime exposure. Potted rice plants were exposed to D2O vapor in the greenhouse for 8 h, under day or night conditions. Deuterium concentrations in free water and organic matter in rice leaves and ears were investigated until harvest time. The formation of organically bound deuterium in the daytime was higher than during the nighttime by the factors of 2.4 for the ear and 2.9 for the leaf. The decrease of the organically bound deuterium concentration in the ear after the nighttime exposure was faster than that after the daytime exposure. Data analysis was carried out using a compartment model in which different generating processes of organic matter were considered. The calculated organically bound deuterium retention in rice agreed with the measured value. PMID:12046759

  18. Is Deuterium Nuclear Fusion Catalyzed by Antineutrinos?

    NASA Astrophysics Data System (ADS)

    Shomer, Isaac

    2010-02-01

    The hypothesis of Fischbach and Jenkins that neutrinos emitted from the sun accelerate radioactive decay is noted. It is thought that neutrinos accelerate beta decay by reacting with neutron-rich nuclides to form a beta particle and a daughter product, with no antineutrino emitted. Conversely, it is proposed that antineutrinos can react with proton-rich nuclides to cause positron decay, with no neutrino emitted. It is also proposed that the nuclear fusion of the hydrogen bomb is triggered not only by the energy of the igniting fission bomb, but by the antineutrinos created by the rapid beta decay of the daughter products in the fission process. The contemplated mechanism for antineutrino initiated fusion is the following: 1. The antineutrinos from the fission daughter products cause positron decay of deuterium by the process outlined above. 2. In a later fusion step, these positrons subsequently react with neutrons in deuterium to create antineutrinos. Electrons are unavailable to annihilate positrons in the plasma of the hydrogen bomb. 3. These antineutrinos thereafter react with more deuterium to form positrons, thereby propagating a chain reaction. )

  19. Deuterium trapping by impurities in copper

    SciTech Connect

    Mitchell, D.J.

    1982-04-01

    The addition of Er, Zr, or Ti to copper provides trapping sites for hydrogen isotopes, which causes the apparent diffusivity of hydrogen to take on values that are smaller than its normal diffusivity in pure copper. This apparent diffusivity can be described in terms of the dopant concentration and the binding energy of the hydrogen isotope to the traps. Criteria are met that enable the results of permeation breakthrough measurements, which were made between 300/sup 0/ and 700 /sup 0/C, to be extrapolated to room temperature. The resultant lag-time for deuterium breakthrough for a 0.25-mm-thick membrane of Cu containing 0.88 at.% Er, for example, exceeds 1000 years at 25 /sup 0/C. Therefore, this alloy is suitable for use in vacuum enclosures where it is necessary to restrict hydrogen permeation for long periods of time. Thermodesorption measurements for samples that were exposed to deuterium reveal that there are two types of traps in these alloys, and demonstrate that deuterium-to-dopant atomic ratios approaching two can be obtained.

  20. The mass dependent and independent equilibrium fractionation of stable mercury isotopes during laboratory synthesis of metacinnabar and other mercury-bearing phases

    NASA Astrophysics Data System (ADS)

    Smith, R. S.; Wiederhold, J. G.; Bourdon, B.; Kretzschmar, R.

    2010-12-01

    Mercury has long been recognized as a contaminant of global concern for its toxicity and bioaccumulation ability. Soils are a primary reservoir for Hg where various processes can transform it into more toxic and mobile forms. Highly contaminated Hg sites, i.e. former mines, generally contain a well-defined geochemical gradient, where typically ore, waste rock, and roasted ore are present. Advancements in MC-ICPMS and the ability to precisely measure mass dependent fractionation (MDF) and mass independent fractionation (MIF) have allowed for the potential use of Hg isotopes as a pollution source tracer and to elucidate Hg cycling mechanisms in soil environments. The objective of this work was to determine if precipitation of Hg-bearing minerals can yield distinct isotopic signatures that can be identified in natural samples. Laboratory synthesis of metacinnabar (β-HgS), an ore mineral, was performed to examine if precipitation could induce MDF and MIF of Hg isotopes. Experiments were conducted using solutions of either Hg(II)-acetate or Hg(II)-nitrate at different pH values. The addition of varying amounts of Na-sulfide solutions to parallel batches was designed to precipitate between 30 and 90% of the initial Hg in solution. Two sets of experiments were run to vary the aging time (hours to days) between precipitation and separation of the supernatant. Additional experiments using an excess of sulfur were also conducted for precipitate characterization. Concentration analyses were conducted using CV-AFS while isotopic analyses were performed using the Nu Instruments MC-ICPMS with cold vapor introduction. Experiments in both systems demonstrated that when sulfur was in excess, precipitates were black and appeared more crystalline. In the Hg-acetate system, precipitates formed during Hg-excess experiments, appeared black and poorly-crystalline, while precipitates of the Hg-nitrate system appeared white to gray and poorly-crystalline. Concentration analyses determined

  1. Mass-dependent and Mass-independent Sulphur Isotope Fractionation Accompanying Thermal- and Photo-chemical Decomposition of Sulphur Bearing Organic Compounds

    NASA Astrophysics Data System (ADS)

    Oduro, Harry; Izon, Gareth; Ono, Shuhei

    2014-05-01

    The bimodal S-isotope record, specifically the transition from mass independent (MIF) to mass dependent fractionation (MDF), is perhaps the most widely cited line of evidence for an irreversible rise in atmospheric oxygen at ca. 2.4Ga. The production and preservation of S-MIF, manifested in both Δ33S and Δ36S, within the geological record are linked to atmospheric O2 via a number of arguments. However, to date, the only mechanism capable of generating S-MIF consistent with the Archaean sedimentary records involves gas-phase ultraviolet irradiation of SO21 photolysis. More recently, Δ33S S-MIF trends have been reported from en vitro thermochemical sulphate reduction (TSR) experiments, prompting authors to question the importance of S-MIF as a proxy for Earth oxidation2. Importantly, whilst emerging TSR experiments3,4 affirm the reported Δ33S trends2, these experiments fail to identify correlated S-MIF between Δ33S and Δ36S values3,4. Realization that S-MIF is confined to Δ33S during TSR, precludes TSR as a mechanism responsible for the origin of the Archaean S-MIF record but strongly suggests the effect originating from a magnetic isotope effect (MIE) associated with 33S nucleus3,4. Clearly, photochemical and thermochemical processes impart different Δ36S/Δ33S trends with significant variation in δ34S; however, a complete experimental elucidation of mechanisms responsible for the S-MIF and S-MIE signatures is lacking. Interestingly, a complete understanding of the S-isotope chemistry during thermal- and photo-chemical decomposition may reveal wavelength and thermal dependence archived in the sedimentary record. Here we extend the experimental database to explore the magnitude and sign of Δ36S/Δ33S and δ34S produced during both photo- and thermochemical processes. Here the organic sulphur compounds (OSC) utilized in these experiments carries diagnostic Δ36S/Δ33S patterns that differ from those reported from photolysis experiment SO2 and from the

  2. The discovery and modeling of energy dependent time-lags and fractional RMS of heartbeat state in GRS 1915+105

    NASA Astrophysics Data System (ADS)

    Mir, Mubashir; Iqbal, Naseer; Pahari, Mayukh; Misra, Ranjeev

    2016-07-01

    We report the discovery and modeling of enigmatic Energy dependent time-lags and fractional RMS of the heartbeat state in GRS 1915+105. The time-lags reveal the crucial information related to geometry of accretion flow, the emission regions and the relation between various spectral parameters. The lag and frms at the fundamental frequency show non-monotonic behavior with energy. The lag increases up to typically ˜10 keV and later shows a reversal and in some observations becomes hard(negative). However, the lags at the harmonic increase with energy and don't show any turn around at least till ˜20 keV. The frms at harmonic has similar non-monotonic behavior as at fundamental, however the variability amplitude is lesser as expected. The lag seen here can have magnitude of the order of seconds, and thus can't be accounted by light travel time effects or comptonization delays. The continuum X-ray spectra can roughly be described by a disk blackbody and a hard X-ray power-law component and from phase resolved spectroscopy it has been shown that the inner disk radius varies during the oscillation We propose the model based on the delayed response of inner disc (DRIOD) radius to the outer accretion rate i;e r_{in}(t)∝ dot{m}^β (t-τ_d). The fluctuating accretion rate varies the inner disk after a certain time delay t_d which could be of the order of the viscous propagation delays. The model very well explains the observed shape and nature of lags and frms at fundamental and harmonic frequencies. We present here the series of observations that constrain the four free parameters of our model. These parameters contain the vital information related to the nature of accretion flow in a highly periodic state like a heartbeat state.

  3. Pion Electroproduction form Helium 3, Deuterium, and Hydrogen

    SciTech Connect

    S. Avery

    2002-05-01

    A series of measurements for pion electroproduction from helium-3, deuterium, and hydrogen were completed at the Thomas Jefferson National Accelerator Facility by the NucPi Collaboration. E91003 began taking data in February 1998 and was completed in April 1998. The longitudinal and transverse parts of the differential cross section were extracted, by means of a Rosenbluth type separation, in the direction parallel to the virtual photon, at Q 2 = 0.4 GeV 2 , for W = 1.15 and W = 1.6 GeV. The mass dependence of the longitudinal cross section should provide insight into the surprising apparent absence of any significant cross section enhancement due to excess pions in the nuclear medium.

  4. Evolution of dispersion in the cosmic deuterium abundance

    NASA Astrophysics Data System (ADS)

    Dvorkin, Irina; Vangioni, Elisabeth; Silk, Joseph; Petitjean, Patrick; Olive, Keith A.

    2016-05-01

    Deuterium is created during big bang nucleosynthesis, and, in contrast to the other light stable nuclei, can only be destroyed thereafter by fusion in stellar interiors. In this Letter, we study the cosmic evolution of the deuterium abundance in the interstellar medium (ISM) and its dispersion using realistic galaxy evolution models. We find that models that reproduce the observed metal abundance are compatible with observations of the deuterium abundance in the local ISM and z ˜ 3 absorption line systems. In particular, we reproduce the low astration factor which we attribute to a low global star formation efficiency. We calculate the dispersion in deuterium abundance arising from different structure formation histories in different parts of the Universe. Our model also predicts a tight correlation between deuterium and metal abundances which could be used to measure the primordial deuterium abundance.

  5. Deuterium incorporation in biomass cell wall components by NMR analysis

    SciTech Connect

    Foston, Marcus B; McGaughey, Joseph; O'Neill, Hugh Michael; Evans, Barbara R; Ragauskas, Arthur J

    2012-01-01

    A commercially available deuterated kale sample was analyzed for deuterium incorporation by ionic liquid solution 2H and 1H nuclear magnetic resonance (NMR). This protocol was found to effectively measure the percent deuterium incorporation at 33%, comparable to the 31% value determined by combustion. The solution NMR technique also suggested by a qualitative analysis that deuterium is preferentially incorporated into the carbohydrate components of the kale sample.

  6. Deuterium magic angle spinning studies of substrates bound to cytochrome P450.

    PubMed

    Lee, H; Ortiz de Montellano, P R; McDermott, A E

    1999-08-17

    We report solid-state deuterium magic angle spinning NMR spectra of perdeuterated adamantane bound to the active site of microcrystalline cytochrome P450cam (CP450cam) in its resting state. CP450cam contains a high-spin ferric (Fe3+) heme in the resting state; the isotropic shift was displaced from the diamagnetic value and varied with temperature consistent with Curie-law dependence. A nondeuterated competitive tighter binding ligand, camphor, was used to displace the adamantane-bound species. This addition resulted in the disappearance of the hyperfine-shifted signal associated with a perdeuterated adamantane bound to CP450cam, while signals presumably associated with adamantane bound to other cavities persisted. We simulated the deuterium spinning side-band intensities for the enzyme-bound species using dipolar hyperfine coupling as the only anisotropic interaction; the deuterium quadrupolar interaction was apparently averaged due to a fast high-symmetry motion. These data provide direct support for previous proposals that substrates are conformationally mobile on the time scale of enzymatic turnover. The simulations suggested that the adamantane binds with an average metal-deuterium distance of 6.2 (+/-0.2) A, corresponding to a dipolar coupling constant of 6.5 (+/-0.5) kHz. PMID:10451377

  7. Diffusion and electrotransport of hydrogen and deuterium in vanadium-titanium and vanadium-chromium alloys

    NASA Astrophysics Data System (ADS)

    Pine, David J.; Cotts, R. M.

    1983-07-01

    The diffusion coefficient D and electrotransport effective charge number Z* of hydrogen and deuterium in V, V1-xTix, and V1-yCry were measured as a function of temperature using resistance techniques. Measurements were performed for hydrogen (deuterium) concentrations of approximately 1 at.% and alloys with x=0.03 and 0.08 and y=0.04 and 0.10. Alloying vanadium with either titanium or chromium was found to lower both D and Z* over the entire temperature range studied (310-480 K). The diffusion data obey an Arrhenius relation, the alloys having larger activation energies for diffusion than pure vanadium. No currently existing microscopic theory seems capable of explaining the dependence of D on alloy composition, nor can the data be consistently explained by a simple two-state trapping model. In every sample, Z* was observed to decrease with increasing temperature and host-metal resistivity for both hydrogen and deuterium. In addition, Z* was found to be larger for deuterium than hydrogen.

  8. A field evaporation deuterium ion source for neutron generators

    SciTech Connect

    Reichenbach, Birk; Solano, I.; Schwoebel, P. R.

    2008-05-01

    Proof-of-principle experiments have demonstrated an electrostatic field evaporation based deuterium ion source for use in compact, high-output deuterium-tritium neutron generators. The ion source produces principally atomic deuterium and titanium ions. More than 100 ML of deuterated titanium thin film can be removed and ionized from a single tip in less than 20 ns. The measurements indicate that with the use of microfabricated tip arrays the deuterium ion source could provide sufficient ion current to produce 10{sup 9}-10{sup 10} n/cm{sup 2} of tip array area.

  9. A field evaporation deuterium ion source for neutron generators

    NASA Astrophysics Data System (ADS)

    Reichenbach, Birk; Solano, I.; Schwoebel, P. R.

    2008-05-01

    Proof-of-principle experiments have demonstrated an electrostatic field evaporation based deuterium ion source for use in compact, high-output deuterium-tritium neutron generators. The ion source produces principally atomic deuterium and titanium ions. More than 100 ML of deuterated titanium thin film can be removed and ionized from a single tip in less than 20 ns. The measurements indicate that with the use of microfabricated tip arrays the deuterium ion source could provide sufficient ion current to produce 109-1010 n/cm2 of tip array area.

  10. Neutron production from puffing deuterium in plasma focus device

    SciTech Connect

    Kubes, P.; Cikhardt, J.; Kortanek, J.; Batobolotova, B.; Rezac, K.; Klir, D.; Kravarik, J.; Paduch, M.; Zielinska, E.; Surala, W.; Sadowski, M. J.; Scholz, M.; Karpinski, L.

    2014-08-15

    The current research has continued on the PF-1000 plasma focus device at the current of 2 MA by comparison of the shots with and without injected deuterium. The increase of the total neutron yield at the level of 10{sup 10}–10{sup 11} per shot was achieved after the compression of about 10 μg/cm of the deuterium from the gas-valve by about 46 μg/cm of the neon or deuterium plasma sheath. It increases five times at the decrease of the puffing deuterium mass to one-half. In shots with neon in the chamber and with puffing deuterium, a considerable decrease was confirmed of the soft X-ray emission in comparison with shots without deuterium injection. This decrease can be explained by the absence of the neon in the region of the compressed and hot plasma. The deuterium plasma from the gas-puff should then be confined in the internal structures both in the phase of implosion as well as during their formation and transformation. In shots with puffing deuterium, the evolution of instabilities in the plasma column was suppressed. The deuterium plasma has a higher conductance and better ability to form expressive and dense plasmoids and to transport the internal current in comparison with neon plasma. Neutrons were produced both at the initial phase of stagnation, as well as at a later time at the evolution of the constrictions and dense plasmoids.

  11. Chemical Behaviors of Energetic Deuterium Implanted into Boron Coatings

    SciTech Connect

    Kodama, H.; Morimoto, Y.; Sasaki, M.; Oyaidu, M.; Oya, Y.; Sagara, A.; Noda, N.; Okuno, K.

    2003-09-15

    To study chemical behaviors of energetic deuterium implanted into boron coating deposited by boronization in fusion devices, two types of boron coating film deposited on silicon and IG-430U were prepared by Plasma Chemical Vapor Deposition (PCVD) technique. Boron polycrystal was used as the reference sample. The chemical behavior of deuterium was investigated by XPS (X-ray photoelectron spectroscopy) and TDS (Thermal adsorption spectroscopy).The 1.0 keV D{sub 2}{sup +} ions were implanted into the samples and the deuterium desorption behavior was studied by TDS. The TDS spectra showed that there were two deuterium release peaks at around 550 and 750 K, which were attributed to the release from deuterium trapped by boron and carbon, respectively. It was also found that most of implanted deuterium was trapped in carbon trapping site compared with boron one.In XPS measurements, the chemical shift of B-1s towards positive side was observed in the film on IG-430U after D{sub 2}{sup +} ion implantation. However, no chemical shifts were found in the film on silicon and boron polycrystal. In highly concentrated boron materials, even if deuterium was implanted into the boron materials, the amount of B-D bond was too low to be measured by XPS. This suggests that deuterium implanted into highly pure boron materials wasn't almost trapped, so that the retention of deuterium in the boron materials would be reduced, compared that in carbon materials.

  12. Laser induced neutron production by explosion of the deuterium clusters

    NASA Astrophysics Data System (ADS)

    Holkundkar, Amol R.; Mishra, Gaurav; Gupta, N. K.

    2014-01-01

    The high energy deuterium ions serve as compact source of neutrons when fused with either deuterium or tritium atoms. In view of this, the explosion of the deuterium clusters under the influence of the laser pulse with intensity ranging from 1015 to 1019 W/cm2 is being studied along with the effect of the cluster radius and inter-cluster distance. The objective of this article is to study the efficiency of the deuterium cluster as a compact source of neutrons under various laser and cluster parameters. It is being observed that the cluster density (number of clusters per unit volume) is quite important to gain high neutron yield.

  13. Spatial reproducibility of complex fractionated atrial electrogram depending on the direction and configuration of bipolar electrodes: an in-silico modeling study.

    PubMed

    Song, Jun-Seop; Lee, Young-Seon; Hwang, Minki; Lee, Jung-Kee; Li, Changyong; Joung, Boyoung; Lee, Moon-Hyoung; Shim, Eun Bo; Pak, Hui-Nam

    2016-09-01

    Although 3D-complex fractionated atrial electrogram (CFAE) mapping is useful in radiofrequency catheter ablation for persistent atrial fibrillation (AF), the directions and configuration of the bipolar electrodes may affect the electrogram. This study aimed to compare the spatial reproducibility of CFAE by changing the catheter orientations and electrode distance in an in-silico left atrium (LA). We conducted this study by importing the heart CT image of a patient with AF into a 3D-homogeneous human LA model. Electrogram morphology, CFAE-cycle lengths (CLs) were compared for 16 different orientations of a virtual bipolar conventional catheter (conv-cath: size 3.5 mm, inter-electrode distance 4.75 mm). Additionally, the spatial correlations of CFAE-CLs and the percentage of consistent sites with CFAE-CL<120 ms were analyzed. The results from the conv-cath were compared with that obtained using a mini catheter (mini-cath: size 1 mm, inter-electrode distance 2.5 mm). Depending on the catheter orientation, the electrogram morphology and CFAE-CLs varied (conv-cath: 11.5±0.7% variation, mini-cath: 7.1±1.2% variation), however the mini-cath produced less variation of CFAE-CL than conv-cath (p<0.001). There were moderate spatial correlations among CFAE-CL measured at 16 orientations (conv-cath: r=0.3055±0.2194 vs. mini-cath: 0.6074±0.0733, p<0.001). Additionally, the ratio of consistent CFAE sites was higher for mini catheter than conventional one (38.3±4.6% vs. 22.3±1.4%, p<0.05). Electrograms and CFAE distribution are affected by catheter orientation and electrode configuration in the in-silico LA model. However, there was moderate spatial consistency of CFAE areas, and narrowly spaced bipolar catheters were less influenced by catheter direction than conventional catheters. PMID:27610037

  14. Spatial reproducibility of complex fractionated atrial electrogram depending on the direction and configuration of bipolar electrodes: an in-silico modeling study

    PubMed Central

    Song, Jun-Seop; Lee, Young-Seon; Hwang, Minki; Lee, Jung-Kee; Li, Changyong; Joung, Boyoung; Lee, Moon-Hyoung

    2016-01-01

    Although 3D-complex fractionated atrial electrogram (CFAE) mapping is useful in radiofrequency catheter ablation for persistent atrial fibrillation (AF), the directions and configuration of the bipolar electrodes may affect the electrogram. This study aimed to compare the spatial reproducibility of CFAE by changing the catheter orientations and electrode distance in an in-silico left atrium (LA). We conducted this study by importing the heart CT image of a patient with AF into a 3D-homogeneous human LA model. Electrogram morphology, CFAE-cycle lengths (CLs) were compared for 16 different orientations of a virtual bipolar conventional catheter (conv-cath: size 3.5 mm, inter-electrode distance 4.75 mm). Additionally, the spatial correlations of CFAE-CLs and the percentage of consistent sites with CFAE-CL<120 ms were analyzed. The results from the conv-cath were compared with that obtained using a mini catheter (mini-cath: size 1 mm, inter-electrode distance 2.5 mm). Depending on the catheter orientation, the electrogram morphology and CFAE-CLs varied (conv-cath: 11.5±0.7% variation, mini-cath: 7.1±1.2% variation), however the mini-cath produced less variation of CFAE-CL than conv-cath (p<0.001). There were moderate spatial correlations among CFAE-CL measured at 16 orientations (conv-cath: r=0.3055±0.2194 vs. mini-cath: 0.6074±0.0733, p<0.001). Additionally, the ratio of consistent CFAE sites was higher for mini catheter than conventional one (38.3±4.6% vs. 22.3±1.4%, p<0.05). Electrograms and CFAE distribution are affected by catheter orientation and electrode configuration in the in-silico LA model. However, there was moderate spatial consistency of CFAE areas, and narrowly spaced bipolar catheters were less influenced by catheter direction than conventional catheters. PMID:27610037

  15. Deuterium and He-3 in cosmic rays

    NASA Technical Reports Server (NTRS)

    Stephens, S. A.

    1989-01-01

    Observation of a large flux of antiprotons in cosmic rays prompted many to postulate new ideas relating to the origin and propagation of cosmic rays in the Galaxy, within the framework of the secondary hypothesis. Under this hypothesis, cosmic rays traverse a large amount of matter either in the source region or in the interstellar space. As a result, large amounts of deuterium and He-3 are also produced as a consequence of spallation of helium and heavier nuclei. In this paper, the spectra of these isotopes are derived, using various models for the propagation of cosmic rays and compare with the existing observations.

  16. Nuclear Structure Corrections in Muonic Deuterium

    SciTech Connect

    Pachucki, Krzysztof

    2011-05-13

    The muonic hydrogen experiment measuring the 2P-2S transition energy [R. Pohl et al., Nature (London) 466, 213 (2010)] is significantly discrepant with theoretical predictions based on quantum electrodynamics. A possible approach to resolve this conundrum is to compare experimental values with theoretical predictions in another system, muonic deuterium {mu}D. The only correction which might be questioned in {mu}D is that due to the deuteron polarizability. We investigate this effect in detail and observe cancellation with the elastic contribution. The total value obtained for the deuteron structure correction in the 2P-2S transition is 1.680(16) meV.

  17. A possible deuterium anomaly: Implications of the CH3D/CH4 mixing ratios in the atmospheres of Jupiter, Saturn, and Uranus

    NASA Technical Reports Server (NTRS)

    Lutz, Barry L.; Debergh, Catherine; Owen, Tobias

    1986-01-01

    Observations of CH3D in the atmospheres of the outer planets provide a test of the theory of deuterium fractionation equilibrium in the formation and evolution of these planets. Recent measurements of the CH3D/CH4 mixing ratios made for Saturn and Uranus are presented and intercompared with current values of Jupiter, illustrating large differences between the planets. Their implied D/H ratios are compared to D/H ratios derived from measurements of HD/H2; and, in the cases of Jupiter and Saturn, they may be incompatible. Implications of these comparisons are discussed in terms of the deuterium fractionation chemistry and possible enrichments of deuterium in the core ices of the planets.

  18. 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.

  19. Fundamental limits to the accuracy of deuterium isotopes for identifying the spatial origin of migratory animals

    USGS Publications Warehouse

    Farmer, A.; Cade, B.S.; Torres-Dowdall, J.

    2008-01-01

    Deuterium isotope analyses have revolutionized the study of migratory connectivity because global gradients of deuterium in precipitation (??DP) are expressed on a continental scale. Several authors have constructed continental scale base maps of ??DP to provide a spatial reference for studying the movement patterns of migratory species and, although they are very useful, these maps present a static, 40-year average view of the landscape that ignores much underlying inter-annual variation. To more fully understand the consequences of this underlying variation, we analyzed the GNIP deuterium data, the source for all current ??DP maps, to estimate the minimum separation in ??DP (and latitude) necessary to conclude with a given level of confidence that distinct ??DP values represent different geographic sites. Extending analyses of ??DP successfully to deuterium in tissues of living organisms, e.g., feathers in migratory birds (??DF), is dependent on the existence of geographic separation of ??DP, where every geographic location has a distribution of values associated with temporal variability in ??DP. Analyses were conducted for three distinct geographic regions: North America, eastern North America (east of longitude 100??W), and Argentina. At the 80% confidence level, the minimum separation values were 12, 7, and 14?? of latitude (equivalent to 53, 31, and 32???) for North America, eastern North America, and Argentina, respectively. Hence, in eastern North America, for example, one may not be able to accurately assign individual samples to sites separated by less than about 7?? of latitude as the distributions of ??DP were not distinct at latitudes <7?? apart. Moreover, two samples that differ by less than 31??? cannot be confidently said to originate from different latitudes. These estimates of minimum separation for ??DP do not include other known sources of variation in feather deuterium (??D F) and hence are a first order approximation that may be useful, in

  20. Direct in vivo characterization of delta 5 desaturase activity in humans by deuterium labeling: Effect of insulin

    SciTech Connect

    el Boustani, S.; Causse, J.E.; Descomps, B.; Monnier, L.; Mendy, F.; Crastes de Paulet, A.

    1989-04-01

    The conversion of dihomogamma linolenic acid (DHLA) into arachidonic acid (AA) was compared in normal subjects and diabetic patients before and after treatment with insulin. The kinetics of the incorporation of deuterium-labeled DHLA and its conversion product, deuterium-labeled AA, was determined in plasma triglycerides, plasma phospholipids, and platelet lipids of subjects after ingestion of 2 g of the labeled precursor. Analysis was performed by gas liquid chromatography-mass spectrometry using multiple ion detection. In normal subjects, the deuterium-labeled DHLA concentration rose to 24 to 69 mg/L in plasma triglycerides four to nine hours after ingestion and to 20 to 34 mg/L in plasma phospholipids about four hours later. Deuterium-labeled AA appeared at 12 hours, rose to 2.4 to 3.8 mg/L between 48 and 72 hours in plasma phospholipids, but remained at the limit of detection in plasma triglycerides and was undetectable in platelet lipids. In diabetic patients both before and after insulin treatment, the deuterium-labeled DHLA concentration in plasma triglycerides and in plasma phospholipids followed the same pattern as in normal subjects. However, the deuterium-labeled arachidonic acid concentration was below 1 mg/L in plasma phospholipids before insulin. After insulin treatment the patients recovered normal DHLA metabolism because deuterium-labeled AA rose in phospholipids to a mean value of 3.5 mg/L, which is in the same range as that observed in normal subjects (3.2 mg/L). The present data provide direct evidence for the conversion of DHLA into AA in humans. The effect of insulin and the data from the literature of animal studies suggest insulin dependence of delta 5 desaturase in humans.

  1. Fractional oscillator.

    PubMed

    Stanislavsky, A A

    2004-11-01

    We consider a fractional oscillator which is a generalization of the conventional linear oscillator in the framework of fractional calculus. It is interpreted as an ensemble average of ordinary harmonic oscillators governed by a stochastic time arrow. The intrinsic absorption of the fractional oscillator results from the full contribution of the harmonic oscillator ensemble: these oscillators differ a little from each other in frequency so that each response is compensated by an antiphase response of another harmonic oscillator. This allows one to draw a parallel in the dispersion analysis for media described by a fractional oscillator and an ensemble of ordinary harmonic oscillators with damping. The features of this analysis are discussed. PMID:15600586

  2. Scaled energy (z) distributions of charged hadrons observed in deep-inelastic muon scattering at 490 GeV from xenon and deuterium targets

    NASA Astrophysics Data System (ADS)

    Adams, M. R.; Aïd, S.; Anthony, P. L.; Baker, M. D.; Bartlett, J.; Bhatti, A. A.; Braun, H. M.; Busza, W.; Carroll, T.; Conrad, J. M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S. K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H. J.; Geesaman, D. F.; Gilman, R.; Green, M. C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V. W.; Jackson, H. E.; Jaffe, D. E.; Jancso, G.; Jansen, D. M.; Kaufman, S.; Kennedy, R. D.; Kirk, T.; Kobrak, H. G.; Krzywdzinski, S.; Kunori, S.; Lord, J. J.; Lubatti, H. J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D. G.; Mohr, W.; Montgomery, H. E.; Morfin, J. G.; Nickerson, R. B.; O'day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F. M.; Ramberg, E. J.; Röser, A.; Ryan, J. J.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schüler, K. P.; Seyerlein, H. J.; Skuja, A.; Snow, G. A.; Söldner-Rembold, S.; Steinberg, P. H.; Stier, H. E.; Stopa, P.; Swanson, R. A.; Talaga, R.; Tentindo-Repond, S.; Trost, H. J.; Venkataramania, H.; Vidal, M.; Wilhelm, M.; Wilkes, J.; Wilson, Richard; Wittek, W.; Wolbers, S. A.; Zhao, T.

    1994-08-01

    Fermilab Experiment-665 measured deep-inelastic scattering of 490 GeV muons off deuterium and xenon targets. Events were selected with a range of energy exchange ν from 100 GeV to 500 GeV and with large ranges of Q2 and xBj: 0.1 GeV2/c2fractional energy (z) distributions of forward-produced hadrons from the two targets have been compared as a function of the kinematics of the scattering; specifically, the kinematic region of ``shadowing'' has been compared to that of nonshadowing. The dependence of the distributions upon the order of the hadrons, determined by the fractional energies, has been examined as well; a strong degree of similarity has been observed in the shapes of the distributions of the different order hadrons. These z distributions, however, show no nuclear dependence, even in the kinematic region of shadowing.

  3. Scaled energy ([ital z]) distributions of charged hadrons observed in deep-inelastic muon scattering at 490 GeV from xenon and deuterium targets

    SciTech Connect

    Adams, M.R.; Aied, S.; Anthony, P.L.; Baker, M.D.; Bartlett, J.; Bhatti, A.A.; Braun, H.M.; Busza, W.; Carroll, T.; Conrad, J.M.; Coutrakon, G.; Davisson, R.; Derado, I.; Dhawan, S.K.; Dougherty, W.; Dreyer, T.; Dziunikowska, K.; Eckardt, V.; Ecker, U.; Erdmann, M.; Eskreys, A.; Figiel, J.; Gebauer, H.J.; Geesaman, D.F.; Gilman, R.; Green, M.C.; Haas, J.; Halliwell, C.; Hanlon, J.; Hantke, D.; Hughes, V.W.; Jackson, H.E.; Jaffe, D.E.; Jancso, G.; Jansen, D.M.; Kaufman, S.; Kennedy, R.D.; Kirk, T.; Kobrak, H.G.E.; Krzywdzinski, S.; Kunori, S.; Lord, J.J.; Lubatti, H.J.; McLeod, D.; Magill, S.; Malecki, P.; Manz, A.; Melanson, H.; Michael, D.G.; Mohr, W.; Montgomery, H.E.; Morfin, J.G.; Nickerson, R.B.; O'Day, S.; Olkiewicz, K.; Osborne, L.; Papavassiliou, V.; Pawlik, B.; Pipkin, F.M.; Ramberg, E.J.; Roeser, A.; Ryan, J.J.; Salvarani, A.; Schellman, H.; Schmitt, M.; Schmitz, N.; Schueler, K.P.; Seyerlein, H.J.; Skuja, A.; Snow, G.A.; Soeldner-Rembold, S.; Steinberg, P.H.; Stier, H.E.; St

    1994-08-01

    Fermilab Experiment-665 measured deep-inelastic scattering of 490 GeV muons off deuterium and xenon targets. Events were selected with a range of energy exchange [nu] from 100 GeV to 500 GeV and with large ranges of [ital Q][sup 2] and [ital x][sub Bj]: 0.1 GeV[sup 2]/[ital c][sup 2][lt][ital Q][sup 2][lt]150 GeV[sup 2]/[ital c][sup 2] and 0.001[lt][ital x][sub Bj][lt]0.5. The fractional energy ([ital z]) distributions of forward-produced hadrons from the two targets have been compared as a function of the kinematics of the scattering; specifically, the kinematic region of shadowing'' has been compared to that of nonshadowing. The dependence of the distributions upon the [ital order] of the hadrons, determined by the fractional energies, has been examined as well; a strong degree of similarity has been observed in the shapes of the distributions of the different order hadrons. These [ital z] distributions, however, show no nuclear dependence, even in the kinematic region of shadowing.

  4. Tables of equation-of-state, thermodynamic properties, and shock Hugoniot for hot dense fluid deuterium

    SciTech Connect

    Zaghloul, Mofreh R.

    2015-11-15

    We present computational results and tables of the equation-of-state, thermodynamic properties, and shock Hugoniot for hot dense fluid deuterium. The present results are generated using a recently developed chemical model that takes into account different high density effects such as Coulomb interactions among charged particles, partial degeneracy, and intensive short range hard core repulsion. Internal partition functions are evaluated in a statistical-mechanically consistent way implementing recent developments in the literature. The shock Hugoniot curve derived from the present tables is overall in reasonable agreement with the Hugoniot derived from the Nova-laser shock wave experiments on liquid deuterium, showing that deuterium has a significantly higher compressibility than predicted by the SESAME tables or by Path Integral Monte Carlo calculations. Computational results are presented as surface plots for the dissociated fraction, degree of ionization, pressure, and specific internal energy for densities ranging from 0.0001 to 40 g/cm{sup 3} and temperatures from 2000 to ∼10{sup 6 }K. Tables for values of the above mentioned quantities in addition to the specific heat at constant pressure, c{sub p}, ratio of specific heats, c{sub p}/c{sub v}, sound speed and Hugoniot curve (for a specific initial state) are presented for practical use.

  5. Deuterium Retention in NSTX with Lithium Conditioning

    SciTech Connect

    Skinner, C. H.; Allain, J. P.; Blanchard, W.; Kugel, H. W.; Maingi, Rajesh; Roquemore, L.; Soukhanovskii, V. A.; Taylor, C. N.

    2011-01-01

    High (approximate to 90%) deuterium retention was observed in NSTX gas balance measurements both with- and without lithiumization of the carbon plasma-facing components. The gas retained in ohmic discharges was measured by comparing the vessel pressure rise after a discharge to that of a gas-only pulse with the pumping valves closed. For neutral beam heated discharges the gas input and gas pumped by the NB cryopanels were tracked. The discharges were followed by outgassing of deuterium that reduced the retention. The relationship between retention and surface chemistry was explored with a new plasma-material interface probe connected to an in vacuo surface science station that exposed four material samples to the plasma. XPS and TDS analysis demonstrated that binding of D atoms in graphite is fundamentally changed by lithium - in particular atoms are weakly bonded in regions near lithium atoms bound to either oxygen or the carbon matrix. This is in contrast to the strong ionic bonding that occurs between D and pure Li. (C) 2010 Elsevier B.V. All rights reserved.

  6. Deuterium retention in NSTX with lithium conditioning

    NASA Astrophysics Data System (ADS)

    Skinner, C. H.; Allain, J. P.; Blanchard, W.; Kugel, H. W.; Maingi, R.; Roquemore, L.; Soukhanovskii, V.; Taylor, C. N.

    2011-08-01

    High (≈90%) deuterium retention was observed in NSTX gas balance measurements both with- and without lithiumization of the carbon plasma-facing components. The gas retained in ohmic discharges was measured by comparing the vessel pressure rise after a discharge to that of a gas-only pulse with the pumping valves closed. For neutral beam heated discharges the gas input and gas pumped by the NB cryopanels were tracked. The discharges were followed by outgassing of deuterium that reduced the retention. The relationship between retention and surface chemistry was explored with a new plasma-material interface probe connected to an in vacuo surface science station that exposed four material samples to the plasma. XPS and TDS analysis demonstrated that binding of D atoms in graphite is fundamentally changed by lithium - in particular atoms are weakly bonded in regions near lithium atoms bound to either oxygen or the carbon matrix. This is in contrast to the strong ionic bonding that occurs between D and pure Li.

  7. Cryotarget Control Software for Liquid Deuterium

    NASA Astrophysics Data System (ADS)

    Brakman, David; Gilfoyle, Gerard; Cuevas, Chris; Christo, Steve; CLAS Collaboration

    2015-10-01

    One of the experiments in Hall B at Jefferson Lab will measure the neutron elastic magnetic form factor with a 12 GeV electron beam striking a liquid deuterium target (LD2) and measuring the resulting debris in the CEBAF Large Acceptance Spectrometer (CLAS12). A program was created that acts as a control system for the LD2 target. It will monitor the deuterium target and send data to the main control system and the shift workers monitoring the experiment in real time. The data include measurements of pressure, temperature, and liquid level. The system will also control setpoints for temperature, heater power, and other parameters as well as download calibration curves. The program was written in LabVIEW, a graphical programming language noted for readily interfacing with lab equipment. This project has completed two stages so far. Simulated data were generated within LabVIEW and passed to subroutines that send, log, and display data on a PC. In the second stage, the PC was connected to a data acquisition board, and test signals were read and analyzed to simulate the target sensors. Work supported by the University of Richmond and the US Department of Energy.

  8. Deuterium storage in nanocrystalline magnesium thin films

    NASA Astrophysics Data System (ADS)

    Checchetto, R.; Bazzanella, N.; Miotello, A.; Brusa, R. S.; Zecca, A.; Mengucci, A.

    2004-02-01

    Nanocrystalline magnesium deuteride thin films with the β-MgD2 structure were prepared by vacuum evaporation of hexagonal magnesium (h-Mg) samples and thermal annealing in 0.15 MPa D2 atmosphere at 373 K. Thermal desorption spectroscopy analysis indicated that the rate-limiting step in the deuterium desorption was given by the thermal decomposition of the deuteride phase. The activation energy Δg of the β-MgD2→h-Mg+D2 reaction scaled from 1.13±0.03 eV in 650-nm-thick films to 1.01±0.02 eV in 75-nm-thick films most likely as consequence of different stress and defect level. Positron annihilation spectroscopy analysis of the thin-film samples submitted to deuterium absorption and desorption cycles reveal the presence of a high concentration of void-like defects in the h-Mg layers after the very first decomposition of the β-MgD2 phase, the presence of these open volume defects reduces the D2 absorption capacity of the h-Mg thin film.

  9. Deuterium trapping by impurities in copper

    SciTech Connect

    Mitchell, D.J.

    1981-01-01

    The addition of Er, Zr, or Ti to copper provides trapping sites for hydrogen isotopes, which causes the apparent diffusivity of hydrogen to take on values that are smaller than its normal diffusivity in pure copper. This apparent diffusivity can be described in terms of the dopant concentration and the binding energy of the hydrogen isotope to the traps. Criteria are met that enable the results of permeation breakthrough measurements, which were made between 300 and 700/sup 0/C, to be extrapolated to room temperature. The resultant lag-time for deuterium breakthrough for a 0.25 mm thick membrane of Cu containing 0.88 atomic percent Er, for example, exceeds 1000 years at 25/sup 0/C. Therefore, this alloy is suitable for use in vacuum enclosures where it is necessary to restrict hydrogen permeation for long periods of time. Thermodesorption measurements for samples that were exposed to deuterium reveal that there are two types of traps in these alloys.

  10. Confinement and heating of a deuterium-tritium plasma

    SciTech Connect

    Hawryluk, R. J.; Adler, H.; Alling, P.; Synakowski, E.

    1994-03-01

    The Tokamak Fusion Test Reactor (TFTR) has performed initial high-power experiments with the plasma fueled by deuterium and tritium to nominally equal densities. Compared to pure deuterium plasmas, the energy stored in the electron and ions increased by ~20%. These increases indicate improvements in confinement associated with the use of tritium and possibly heating of electrons by α-particles.

  11. Plasma transport of vitamin K in men using deuterium-labeled collard greens.

    PubMed

    Erkkilä, Arja T; Lichtenstein, Alice H; Dolnikowski, Gregory G; Grusak, Michael A; Jalbert, Susan M; Aquino, Katherine A; Peterson, James W; Booth, Sarah L

    2004-02-01

    The plasma transport of stable isotope-labeled phylloquinone at physiologic doses from food was studied. A single bolus of 100 g (396 +/- 28 microg phylloquinone) deuterium-labeled collard greens was fed with a breakfast containing 24 g fat to 5 men (26 to 71 years). Eleven blood samples were obtained over 216 hours. Phylloquinone concentrations in plasma and lipoprotein subfractions were measured using high-performance liquid chromatography (HPLC), and the ion abundances of deuterated and endogenous phylloquinone were determined using gas chromatography/mass spectrometry (GC/MS). Plasma total phylloquinone concentrations peaked at 6 to 9 hours (10.51 +/- 4.38 to 8.30 +/- 4.64 nmol/L) and returned to baseline by 24 hours (1.26 +/- 0.38 nmol/L). The triglyceride-rich lipoprotein (TRL) fraction was the major carrier of phylloquinone; low-density lipoprotein (LDL) and high-density lipoprotein (HDL) fractions contained smaller amounts. Maximum enrichment of plasma and TRL phylloquinone with deuterium (88% and 89%, respectively) was reached at 6 hours, respectively; t(1/2) was 22.8 hours (n = 3). Deuterated-phylloquinone was not detectable in plasma or TRL fraction at 72 hours. These results suggest rapid uptake and transport of physiologic doses of phylloquinone. PMID:14767874

  12. Deuterium enrichment by selective photoinduced dissociation of a multihalogenated organic compound

    DOEpatents

    Marling, John B.; Herman, Irving P.

    1981-01-01

    A method for deuterium enrichment by photoinduced dissociation which uses as the deuterium source a multihalogenated organic compound selected from the group consisting of a dihalomethane, a trihalomethane, a 1,2-dihaloethene, a trihaloethene, a tetrahaloethane and a pentahaloethane. The multihalogenated organic compound is subjected to intense infrared radiation at a preselected wavelength to selectively excite and thereby induce dissociation of substantially only those molecules containing deuterium to provide a deuterium enriched dissociation product. The deuterium enriched product may be combusted with oxygen to provide deuterium enriched water. The deuterium depleted undissociated molecules may be redeuterated by treatment with a deuterium source such as water.

  13. Numerical study of the ablative Richtmyer-Meshkov instability of laser-irradiated deuterium and deuterium-tritium targets

    NASA Astrophysics Data System (ADS)

    Marocchino, Alberto; Atzeni, Stefano; Schiavi, Angelo

    2010-11-01

    The Richtmyer-Meshkov instability (RMI) at the ablation front of laser-irradiated planar targets is investigated by two-dimensional numerical hydrodynamics simulations. The linear evolution of perturbations seeded either by surface roughness or target inhomogeneity is studied for perturbation wavelengths in the range 10≤λ≤400 μm and laser intensity 4×1012≤I≤4×1014 W/cm2 (with laser wavelength λlaser=0.35 μm). Thin and thick cryogenic deuterium or deuterium-tritium (DT) planar targets are considered. For targets irradiated at constant intensity, it is found that perturbations with wavelength below a given threshold perform damped oscillations, while perturbations above such a threshold are unstable and oscillate with growing amplitude. This is qualitatively in agreement with theoretical predictions by Goncharov et al. [Phys. Plasmas 13, 012702 (2006)], according to which ablation related processes stabilize perturbations with kDc≫1, where Dc is the distance between the ablation front and critical density for laser propagation. For kDc<1 a weakly growing Landau-Darrieus instability (LDI) is instead excited. The stability threshold increases substantially with laser intensity, given the dependence of Dc on laser intensity I (roughly Dc∝I, according to the present simulations). Direct-drive laser fusion targets are irradiated by time-shaped pulses, with a low intensity initial foot. In this case, perturbations with wavelengths below some threshold (about 10 μm, for typical ignition-class all-DT targets) are damped after an initial growth. In a thin target, initial perturbations, either damped or amplified by RMI and LDI, seed the subsequent Rayleigh-Taylor instability. Finally, it is shown that RMI growth of fusion targets can be reduced by using laser pulses including an initial adiabat-shaping picket (originally proposed to reduce the growth of Rayleigh-Taylor instability).

  14. Recovery capacity of glial progenitors after in vivo fission-neutron or X irradiation: age dependence, fractionation and low-dose-rate irradiations.

    PubMed

    Philippo, H; Winter, E A M; van der Kogel, A J; Huiskamp, R

    2005-06-01

    Previous experiments on the radiosensitivity of O-2A glial progenitors determined for single-dose fission-neutron and X irradiation showed log-linear survival curves, suggesting a lack of accumulation of recovery of sublethal damage. In the present study, we addressed this question and further characterized the radiobiological properties of these glial stem cells by investigating the recovery capacity of glial stem cells using either fractionated or protracted whole-body irradiation. Irradiations were performed on newborn, 2-week-old or 12-week-old rats. Fractionated irradiations (four fractions) were performed with 24-h intervals, followed by cell isolations 16- 24 h after the last irradiation. Single-dose irradiations were followed by cell isolation 16-24 h after irradiation or delayed cell isolation (4 days after irradiation) of the O-2A progenitor cells from either spinal cord (newborns) or optic nerve (2- and 12-week-old rats). Results for neonatal progenitor cell survival show effect ratios for both fractionated fission-neutron and X irradiation of the order of 1.8 when compared with single-dose irradiation. A similar ratio was found after single-dose irradiation combined with delayed plating. Comparable results were observed for juvenile and adult optic nerve progenitors, with effect ratios of the order of 1.2. The present investigation clearly shows that fractionated irradiation regimens using X rays or fission neutrons and CNS tissue from rats of various ages results in an increase in O-2A progenitor cell survival while repair is virtually absent. This recovery of the progenitor pool after irradiation can be observed at all ages but is greatest in the neonatal spinal cord and can probably be attributed to repopulation. PMID:15913395

  15. Influence of displacement damage on deuterium and helium retention in austenitic and ferritic-martensitic alloys considered for ADS service

    NASA Astrophysics Data System (ADS)

    Voyevodin, V. N.; Karpov, S. A.; Kopanets, I. E.; Ruzhytskyi, V. V.; Tolstolutskaya, G. D.; Garner, F. A.

    2016-01-01

    The behavior of ion-implanted hydrogen (deuterium) and helium in austenitic 18Cr10NiTi stainless steel, EI-852 ferritic steel and ferritic/martensitic steel EP-450 and their interaction with displacement damage were investigated. Energetic argon irradiation was used to produce displacement damage and bubble formation to simulate nuclear power environments. The influence of damage morphology and the features of radiation-induced defects on deuterium and helium trapping in structural alloys was studied using ion implantation, the nuclear reaction D(3He,p)4He, thermal desorption spectrometry and transmission electron microscopy. It was found in the case of helium irradiation that various kinds of helium-radiation defect complexes are formed in the implanted layer that lead to a more complicated spectra of thermal desorption. Additional small changes in the helium spectra after irradiation with argon ions to a dose of ≤25 dpa show that the binding energy of helium with these traps is weakly dependent on the displacement damage. It was established that retention of deuterium in ferritic and ferritic-martensitic alloys is three times less than in austenitic steel at damage of ˜1 dpa. The retention of deuterium in steels is strongly enhanced by presence of radiation damages created by argon ion irradiation, with a shift in the hydrogen release temperature interval of 200 K to higher temperature. At elevated temperatures of irradiation the efficiency of deuterium trapping is reduced by two orders of magnitude.

  16. Deuterium Enrichment of Amino and Hydroxy Acids Found in the Murchison Meteorite: Constraints on Parent Body Conditions

    NASA Technical Reports Server (NTRS)

    Lerner, Narcinda R.; Chang, Sherwood (Technical Monitor)

    1997-01-01

    The alpha-amino and alpha-hydroxy acids found in the Murchison carbonaceous chondrite are deuterium enriched. These compounds are thought to have originated from common deuterium enriched carbonyl precursors, by way of a Strecker synthesis which took place in a solution of HCN, NH3, and carbonyl compounds during the period of aqueous alteration of the meteorite parent body. However, the hydroxy acids found on Murchison are less deuterium enriched than the amino acids. With the objective of determining if the discrepancy in deuterium enrichment between the amino acids and the hydroxy acids found on Murchison is consistent with their formation in a Strecker synthesis, we have measured the deuterium content of alpha-amino and alpha-hydroxy acids produced in solutions of deuterated carbonyl compounds, KCN and NH4Cl, and also in mixtures of such solutions and Allende dust at 263 K and 295 K. Retention of the isotopic signature of the starting carbonyl by both alpha amino acids and alpha hydroxy acids is more dependent upon temperature, concentration and pH than upon the presence of meteorite dust in the solution. The constraints these observations place on Murchison parent body conditions will be discussed.

  17. Thermal desorption behavior of deuterium for 6 MeV Fe ion irradiated W with various damage concentrations

    NASA Astrophysics Data System (ADS)

    Oya, Yasuhisa; Li, Xiaochun; Sato, Misaki; Yuyama, Kenta; Zhang, Long; Kondo, Sosuke; Hinoki, Tatsuya; Hatano, Yuji; Watanabe, Hideo; Yoshida, Naoaki; Chikada, Takumi

    2015-06-01

    W samples were irradiated at 300 K with 6 MeV Fe ion with damage concentrations in the range from 0.0003 to 1.0 displacements per atom (dpa) and then implanted at 300 K with 500 eV D ions to a fluence of 5 × 1021 D/m2. Deuterium retention in the damaged samples was examined in situ by thermal desorption spectrometry (TDS). Simulation of the TDS spectra was performed using the Hydrogen Isotope Diffusion and Trapping (HIDT) simulation code to reveal the binding energies for deuterium captured by the ion-induced defects. It has been shown that the deuterium TDS spectra consist of two or three peaks (depending on the damage concentration) at about 400, 600 and 800 K, and can be simulated by the HIDT simulation code with the use of hydrogen-trap binding energies of 0.65, 1.25, and 1.55 eV.

  18. Temperature Dependent Sr-Isotope (δ 88Sr) and Ca-Isotope (δ 44Ca) Fractionation in Carbonate Precipitates and Corals

    NASA Astrophysics Data System (ADS)

    Eisenhauer, A.; Fietzke, J.; Gussone, N.; Böhm, F.; Bock, B.; Nägler, T.

    2003-12-01

    The knowledge of the influence of temperature and other environmental factors on isotope fractionation of divalent cations like Ca2+ and Sr2+ during inorganic and biogenic controlled precipitation of calcium carbonate is crucial for their interpretation as paleo proxies. In order to extend our earlier studies on Ca-isotope fractionation (e.g. Gussone et al., 2003), we determined δ 88Sr isotope ratios on seawater and on corals. We define the stable Sr isotope ratio as δ 88Sr=((88Sr/86Sr)Sample/(88Sr/86Sr)Standard -1)*1000; Sr Standard is NBS 987. First measurements of the IAPSO seawater standard result in δ 88Sr of 0.38+/-0.02 ‰ . Coral CaCO3 precipitated from seawater in a temperature range from about 22° C to about 27° C correspond to δ 88Sr-values ranging from 0.17 ‰ to about 0.32 ‰ indicating that carbonate precipitated from seawater is isotopically lighter than seawater itself. The slope of 0.027 ‰ /° C for the temperature-δ 88Sr relationship in corals is about a factor of 1.7 larger than the slope of δ 44Ca ratios in inorganically precipitated aragonite. However, the fractionation α (T)=((88Sr/86Sr)CaCO3)/(88Sr/86Sr)Seawater) at a given temperature is about one order of magnitude less for Sr-isotopes relative to Ca-isotopes. The larger temperature-δ 88Sr gradient in comparison to the Ca-isotopes is interpreted to reflect the smaller ion potential and the correspondingly smaller mass of the associated Sr2+-aquocomplex. The observation that δ 88Sr and δ 44Ca are positively correlated with temperature points to the likelihood that kinetic or equilibrium fractionation effects and the mass of the associated acquocomplex control the degree of divalent cation isotope fractionation during CaCO3-precipitation. Reference: Gussone N., Eisenhauer A., Heuser A., Dietzel M., Bock B., Böhm F., Spero H., Lea D. W., Bijma J., and Nägler T. F. (2003) Model for Kinetic Effects on Calcium Isotope Fractionation (δ 44Ca) in Inorganic Aragonite and Cultured

  19. Deuterium enrichment of polycyclic aromatic hydrocarbons by photochemically induced exchange with deuterium-rich cosmic ices

    NASA Technical Reports Server (NTRS)

    Sandford, S. A.; Bernstein, M. P.; Allamandola, L. J.; Gillette, J. S.; Zare, R. N.

    2000-01-01

    The polycyclic aromatic hydrocarbon (PAH) coronene (C24H12) frozen in D2O ice in a ratio of less than 1 part in 500 rapidly exchanges its hydrogen atoms with the deuterium in the ice at interstellar temperatures and pressures when exposed to ultraviolet radiation. Exchange occurs via three different chemical processes: D atom addition, D atom exchange at oxidized edge sites, and D atom exchange at aromatic edge sites. Observed exchange rates for coronene (C24H12)-D2O and d12-coronene (C24D12)-H2O isotopic substitution experiments show that PAHs in interstellar ices could easily attain the D/H levels observed in meteorites. These results may have important consequences for the abundance of deuterium observed in aromatic materials in the interstellar medium and in meteorites. These exchange mechanisms produce deuteration in characteristic molecular locations on the PAHs that may distinguish them from previously postulated processes for D enrichment of PAHs.

  20. Hydroxy-terminated conjugated polymer nanoparticles have near-unity bright fraction and reveal cholesterol-dependence of IGF1R nanodomains.

    PubMed

    Koner, Apurba L; Krndija, Denis; Hou, Qiong; Sherratt, David J; Howarth, Mark

    2013-02-26

    Fluorescent nanoparticles have enabled many discoveries regarding how molecular machines function. Quantum dots have been the dominant class of fluorescent nanoparticles but suffer from blinking and from a substantial dark fraction--particles where the fluorescence is never seen--complicating any analysis of biological function. Nanoparticles composed of conjugated fluorescent polymers (Pdots) have recently been shown to have high brightness and no blinking. Here we develop a robust and efficient means to measure the dark fraction of Pdots, conjugating Atto dyes to the nanoparticles and testing fluorescence colocalization of dye and Pdot puncta. This established that the Pdots we generated had minimal dark fraction: ∼3%. The application of nanoparticles in biological environments is highly sensitive to surface functionalization. For Pdots we found that passivation with uncharged hydroxy-terminated polyethylene glycol caused a dramatic reduction in nonspecific cell binding and aggregation compared to a charged coating. Using carbonyl di-imidazole the hydroxy-Pdots were functionalized efficiently with streptavidin for high stability targeting, allowing specific labeling of mammalian cells. Type I insulin-like growth factor receptor (IGF1R) regulates cell survival and development, with roles in aging, heart disease, and cancer. We used hydroxy-Pdots to track the dynamics of IGF1R on a breast cancer cell-line, determining the diffusion characteristics and showing cholesterol-containing membrane nanodomains were important for receptor mobility at the plasma membrane. The near-unity bright fraction and low nonspecific binding of hydroxy-Pdots, combined with Pdot photostability and lack of blinking, provides many advantages for investigations at the single molecule level. PMID:23330847

  1. Temperature dependence of oxygen- and clumped isotope fractionation in carbonates: A study of travertines and tufas in the 6-95 °C temperature range

    NASA Astrophysics Data System (ADS)

    Kele, Sándor; Breitenbach, Sebastian F. M.; Capezzuoli, Enrico; Meckler, A. Nele; Ziegler, Martin; Millan, Isabel M.; Kluge, Tobias; Deák, József; Hanselmann, Kurt; John, Cédric M.; Yan, Hao; Liu, Zaihua; Bernasconi, Stefano M.

    2015-11-01

    Conventional carbonate-water oxygen isotope thermometry and the more recently developed clumped isotope thermometer have been widely used for the reconstruction of paleotemperatures from a variety of carbonate materials. In spite of a large number of studies, however, there are still large uncertainties in both δ18O- and Δ47-based temperature calibrations. For this reason there is a need to better understand the controls on isotope fractionation especially on natural carbonates. In this study we analyzed oxygen, carbon and clumped isotopes of a unique set of modern calcitic and aragonitic travertines, tufa and cave deposits from natural springs and wells. Together these samples cover a temperature range from 6 to 95 °C. Travertine samples were collected close to the vents of the springs and from pools, and tufa samples were collected from karstic creeks and a cave. The majority of our vent and pool travertines and tufa samples show a carbonate-water oxygen isotope fractionation comparable to the one of Tremaine et al. (2011) with some samples showing higher fractionations. No significant difference between the calcite-water and aragonite-water oxygen isotope fractionation could be observed. The Δ47 data from the travertines show a strong relationship with temperature and define the regression Δ47 = (0.044 ± 0.005 × 106)/T2 + (0.205 ± 0.047). The pH of the parent solution, mineralogy and precipitation rate do not appear to significantly affect the Δ47-signature of carbonates, compared to the temperature effect and the analytical error. The tufa samples and three biogenic calcites show an excellent fit with the travertine calibration, indicating that this regression can be used for other carbonates as well. This work extends the calibration range of the clumped isotope thermometer to travertine and tufa deposits in the temperature range from 6 °C to 95 °C.

  2. Scaling and long-range dependence in option pricing V: Multiscaling hedging and implied volatility smiles under the fractional Black-Scholes model with transaction costs

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Tian

    2011-05-01

    This paper deals with the problem of discrete time option pricing using the fractional Black-Scholes model with transaction costs. Through the ‘anchoring and adjustment’ argument in a discrete time setting, a European call option pricing formula is obtained. The minimal price of an option under transaction costs is obtained. In addition, the relation between scaling and implied volatility smiles is discussed.

  3. Ignition of deuterium-trtium fuel targets

    DOEpatents

    Musinski, Donald L.; Mruzek, Michael T.

    1991-01-01

    A method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom.

  4. Ignition of deuterium-tritium fuel targets

    DOEpatents

    Musinski, D.L.; Mruzek, M.T.

    1991-08-27

    Disclosed is a method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom. 5 figures.

  5. Deuterium and hydrogen flows in the thermosphere

    NASA Technical Reports Server (NTRS)

    Breig, E. L.; Hanson, W. B.

    1991-01-01

    Processes that affect vertical distributions and flows of deuterium and hydrogen between 100 and 500 km in the daytime thermosphere are investigated using a steady state numerical model that includes HD and H2 molecular flows, relevant chemistry, and transport by both molecular and eddy diffusion. The results of calculations indicate that the outward thermospheric fuxes and, hence, the planetary loss rates for D must be large compared to evaporative escape (as is also the case for H), confirming the suggestion of Breig et al. (1987). Results of measurements of H in the mesosphere and lower thermosphere and of H and D in the thermosphere were used to derive upward fluxes through the daytime thermosphere, showing that the upward fluxes exceeded the corresponding Jeans evaporative escape rates by factors of about 5 for H, and greater than 500 for D.

  6. Catalyzed deuterium fueled tandem mirror reactor assessment

    SciTech Connect

    Dobrott, D.

    1985-01-01

    This study was part of a Department of Energy supported alternate fusion fuels program at Science Applications International Corp. The purpose of this portion of the study is to perform an assessment of a conceptual tandem mirror reactor (TMR) that is fueled by the catalyzed-deuterium (Cat-d) fuel cycle with respect to the physics, technology, safety, and cost. Achievable stable betas and magnet configurations are found to be comparable for the Cat-d and d-t fueled TMR. A comparison with respect to cost, reactor performance, and technology requirements for a Cat-d fueled reactor and a comparable d-t fueled reactor such as MARS is also made.

  7. Deuterium plasma-material wall interactions

    NASA Astrophysics Data System (ADS)

    Tien, J. K.; Gross, R. A.

    1981-10-01

    During the final year of this program we completed our study of plasma interactions with material surfaces. Analysis of unipolar arc damage on the microstructure of Ti-6Al-4V was the final part of the study of plasma-metal interactions. Unipolar arcing was found to be the most severe damage mechanism for this alloy and the degree of damage was very sensitive to the metal microstructure. ATJ-S graphite specimens were exposed to hot deuterium plasma and were examined for surface damage. The residual gas in the plasma device was studied using a monopole gas analyzer so as to determine the type and quantity of hydrocarbon species produced by the plasma-graphite interaction.

  8. (Deuterium-deuterium)-driven experimental hybrid blankets and their neutronic analyses

    SciTech Connect

    Kumar, A.; Sahin, S.

    1984-09-01

    The impressive progress made so far toward the achievement of the physics goal of ignited fusion fuel of deuterium-tritium (D-T) is stirring the scientific community to look back and work for the earliest possible introduction of advanced fusion fuel based reactors with the ultimate objective of very clean, safe, and limitless fusion power. As the introduction of advanced fuel fusion drivers is expected to be in phases due to energetics considerations, it is quite instructive to examine the neutronic aspects of deuterium-deuterium (D-D) neutron driven hybrid blankets. The neutronics investigations of some compact hybrid blankets that could be tested experimentally are presented. The blanket designs are selected to conform to a rather small experimental chamber of the LOTUS fusionfission hybrid facility. The parallelepiped-shaped blankets are driven by a (D-D) neutron source from one side. The fertile fuel is either ThO/sub 2/, natural UO/sub 2/, or LOTUS UO/sub 2/. The tritium breeders are chosen from lithium, LiAlO/sub 2/, or Li/sub 2/O. The relative performances of different fertile fuels and tritium breeders are compared. The performance characteristics of ThO/sub 2/ blankets driven by (D-T) and (D-D) neutrons are compared. The improvement in performance characteristics obtained by the introduction of actinides as multipliers with ThO/sub 2/ hybrid blankets is also investigated.

  9. FCC main fractionator revamps

    SciTech Connect

    Golden, S.W.; Martin, G.R.; Sloley, A.W. )

    1993-03-01

    Structured packing use in fluid catalytic cracker (FCC) main fractionators significantly impacts unit pressure profile. Unit pressure balance links the FCC main fractionator, reactor, regenerator, air compressor and wet gas compressor. Unit pressure balance should be viewed as a design variable when evaluating FCC unit revamps. Depending upon limitations of the particular FCC unit, capacity increases of 12.5% to 22.5% have been achieved without modifications to major rotating equipment, by revamping FCC main fractionators with structured packing. An examination of three FCC main fractionator revamps show improvements to pressure profiles and unit capacity. The three revamps described included a wet gas compressor volume limit; an air blower limitation; and a wet gas compressor motor limitation.

  10. Hydrogen-deuterium exchange on plasma-exposed W and SS surface

    NASA Astrophysics Data System (ADS)

    Takagi, Ikuji; Nomura, Shinji; Minamimoto, Toshihiro; Akiyoshi, Masafumi; Kobayashi, Taishi; Sasaki, Takayuki

    2015-08-01

    The desorption cross section for hydrogen isotopes adsorbed on stainless steel (SS) and tungsten (W) has been evaluated experimentally to provide basic information on tritium exchange. One side of a sample sheet was alternately exposed to H and D plasma, and deuterium density on the surface was repeatedly observed using nuclear reaction analysis (NRA) under continuous plasma exposure. From the time dependent change in the deuterium density, the desorption cross sections for SS and W were estimated to be 6.9 ± 2.3 × 10-23 m2 and 4.6 ± 1.0 × 10-23 m2, respectively. No significant differences in the cross section between H and D plasma were observed. Recombinative desorption was found to dominate the desorption process owing to the low incident energy of hydrogen atoms.

  11. Ground-state phases of polarized deuterium species

    SciTech Connect

    Panoff, R.M.; Clark, J.W.

    1987-10-01

    Microscopic prediction of the ground-state phase of electron-spin-aligned bulk atomic deuterium (Darrow-down) is attempted, based on the variational Monte Carlo method. The accurate pair potential of Kolos and Wolniewicz is assumed, and three versions of Darrow-down are considered, which, respectively, involve one, two, and three equally occupied nuclear spin states. The most definitive results on the zero-temperature equations of state of these systems are obtained with optimized ground-state trial wave functions incorporating Jastrow pair correlations, triplet correlations, and momentum-dependent backflow effects. The species Darrow-down/sub 3/ is bound already at the pure Jastrow level, while the energy expectation value of Darrow-down/sub 2/ dips below zero upon supplementing the Jastrow description by triplets and momentum-dependent backflow. The variational energy of Darrow-down/sub 1/ remains positive under all current refinements of the ground-state trial function. We conclude that the systems Darrow-down/sub 3/ and Darrow-down/sub 2/, if they could be manufactured and stabilized at relevant densities, would be Fermi liquids at sufficiently low temperature; on the other hand, it is likely that Darrow-down/sub 1/ would remain gaseous down to absolute zero.

  12. The deuterium content of water in some volcanic glasses

    USGS Publications Warehouse

    Friedman, I.; Smith, R.L.

    1958-01-01

    The deuterium-hydrogen composition (relative to Lake Michigan water = 0.0) of water extractsd from coexisting perlite and obsidian from eleven different localities was determined. The water content of the obsidians is generally from 0.09 to 0.29 per cent by weight, though two samples from near Olancha, California, contain about 0.92 per cent. The relative deuterium concentration is from -4.6 to -12.3 per cent. The coexisting perlite contains from 2.0 to 3.8 per cent of water with a relative deuterium concentration of -3.1 to -16.6 per cent. The deuterium concentration in the perlites is not related to that in the enclosed obsidian. The deuterium concentration in the perlite water is related to the deuterium concentration of the modern meteoric water and the perlite water contains approximately 4 per cent less deuterium than does the groundwater of the area in which the perlites occur. The above relations hold true for perlites from northern New Mexico, east slope of the Sierra Nevada. California Coast Range, Yellowstone Park, Wyoming, and New Zealand. As the water in the obsidian is unrelated to meteoric water, but the enclosing perlite water is related, we believe that this is evidence for the secondary hydration of obsidian to form high water content perlitic glass. ?? 1958.

  13. Hydroxy-Terminated Conjugated Polymer Nanoparticles Have Near-Unity Bright Fraction and Reveal Cholesterol-Dependence of IGF1R Nanodomains

    PubMed Central

    2013-01-01

    Fluorescent nanoparticles have enabled many discoveries regarding how molecular machines function. Quantum dots have been the dominant class of fluorescent nanoparticles but suffer from blinking and from a substantial dark fraction—particles where the fluorescence is never seen—complicating any analysis of biological function. Nanoparticles composed of conjugated fluorescent polymers (Pdots) have recently been shown to have high brightness and no blinking. Here we develop a robust and efficient means to measure the dark fraction of Pdots, conjugating Atto dyes to the nanoparticles and testing fluorescence colocalization of dye and Pdot puncta. This established that the Pdots we generated had minimal dark fraction: ∼3%. The application of nanoparticles in biological environments is highly sensitive to surface functionalization. For Pdots we found that passivation with uncharged hydroxy-terminated polyethylene glycol caused a dramatic reduction in nonspecific cell binding and aggregation compared to a charged coating. Using carbonyl di-imidazole the hydroxy-Pdots were functionalized efficiently with streptavidin for high stability targeting, allowing specific labeling of mammalian cells. Type I insulin-like growth factor receptor (IGF1R) regulates cell survival and development, with roles in aging, heart disease, and cancer. We used hydroxy-Pdots to track the dynamics of IGF1R on a breast cancer cell-line, determining the diffusion characteristics and showing cholesterol-containing membrane nanodomains were important for receptor mobility at the plasma membrane. The near-unity bright fraction and low nonspecific binding of hydroxy-Pdots, combined with Pdot photostability and lack of blinking, provides many advantages for investigations at the single molecule level. PMID:23330847

  14. Impacts of ENSO events on cloud radiative effects in preindustrial conditions: Changes in cloud fraction and their dependence on interactive aerosol emissions and concentrations

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Russell, Lynn M.; Xu, Li; Lou, Sijia; Lamjiri, Maryam A.; Somerville, Richard C. J.; Miller, Arthur J.; Cayan, Daniel R.; DeFlorio, Michael J.; Ghan, Steven J.; Liu, Ying; Singh, Balwinder; Wang, Hailong; Yoon, Jin-Ho; Rasch, Philip J.

    2016-06-01

    We use three 150 year preindustrial simulations of the Community Earth System Model to quantify the impacts of El Niño-Southern Oscillation (ENSO) events on shortwave and longwave cloud radiative effects (CRESW and CRELW). Compared to recent observations from the Clouds and the Earth's Radiant Energy System data set, the model simulation successfully reproduces larger variations of CRESW and CRELW over the tropics. The ENSO cycle is found to dominate interannual variations of cloud radiative effects. Simulated cooling (warming) effects from CRESW (CRELW) are strongest over the tropical western and central Pacific Ocean during warm ENSO events, with the largest difference between 20 and 60 W m-2, with weaker effects of 10-40 W m-2 over Indonesian regions and the subtropical Pacific Ocean. Sensitivity tests show that variations of cloud radiative effects are mainly driven by ENSO-related changes in cloud fraction. The variations in midlevel and high cloud fractions each account for approximately 20-50% of the interannual variations of CRESW over the tropics and almost all of the variations of CRELW between 60°S and 60°N. The variation of low cloud fraction contributes to most of the variations of CRESW over the midlatitude oceans. Variations in natural aerosol concentrations explained 10-30% of the variations of both CRESW and CRELW over the tropical Pacific, Indonesian regions, and the tropical Indian Ocean. Changes in natural aerosol emissions and concentrations enhance 3-5% and 1-3% of the variations of cloud radiative effects averaged over the tropics.

  15. Deuterium in astrophysical ice analogues: Isotope exchange and IR detection sensitivity for HDO

    NASA Astrophysics Data System (ADS)

    Escribano, R. M.; Galvez, O.; Mate, B.; Herrero, V. J.

    2011-12-01

    Among D-bearing molecules, water is especially interesting from an astrophysical point of view. Although the deuterium content of water in astronomical environments is relatively small as compared with other molecules, it holds most valuable information, still largely undeciphered, on the dynamics of formation and evaporation of ice grain mantels in protostellar regions [1], and is crucial for the understanding of the formation of the Solar System and the Earth [2]. In this work, we have used the OD stretching bands of HDO and D2O molecules in various ice mixtures formed by vapor deposition on a cold substrate (see ref [3] for a description of the experimental set-up) to study the sensitivity of the IR technique for the detection of HDO in ice samples, and to monitor processes of H/D isotope exchange in these solids. It is found that the detection sensitivity is strongly dependent on the ice structure. The OD band is extremely broad and tends to disappear into the absorption continuum of H2O for low temperature amorphous samples. Detectable HDO/H2O ratios with this technique may range from a few per cent for amorphous samples to a few per thousand in crystalline ice. These relatively high upper limits and the appreciable dependence of the band shape on temperature, complicating the interpretation of data from many lines of sight, may question the usefulness of this technique. Isotopic H/D exchange in mixed ices of H2O/D2O is found to start at ~ 120 K and is greatly accelerated at 150 K, as crystallization proceeds in the ice. The process is mainly driven by proton transfer assisted by orientational defect mobility. Annealed amorphous samples are more favourable for isotope exchange than samples directly formed in the crystalline phase. The annealing process seems to lead to polycrystalline ice morphology with a higher defect activity. The present data emphasize the relevance of a depletion mechanism for D atoms in hydroxylic bonds in the solid state, recently

  16. Observations of interstellar hydrogen and deuterium toward Alpha Centauri A

    NASA Technical Reports Server (NTRS)

    Landsman, W. B.; Henry, R. C.; Moos, H. W.; Linsky, J. L.

    1984-01-01

    A composite profile is presented of the Ly-alpha emission line of Alpha Cen A, obtained from 10 individual spectra with the high-resolution spectrograph aboard the International Ultraviolet Explorer (IUE) satellite. There is excellent overall agreement with two previous Copernicus observations. Interstellar deuterium is detected, and a lower limit is set on the deuterium to hydrogen ratio of nDI/nHI greater than 8 x 10 to the -6th. In addition, the deuterium bulk velocity appears blueshifted by 8 + or - 2 km/s with respect to interstellar hydrogen, suggesting a nonuniform medium along the line of sight.

  17. Fraction Reduction through Continued Fractions

    ERIC Educational Resources Information Center

    Carley, Holly

    2011-01-01

    This article presents a method of reducing fractions without factoring. The ideas presented may be useful as a project for motivated students in an undergraduate number theory course. The discussion is related to the Euclidean Algorithm and its variations may lead to projects or early examples involving efficiency of an algorithm.

  18. Pion transfer from hydrogen to deuterium in H2+D2 gas mixtures

    NASA Astrophysics Data System (ADS)

    Weber, P.; Armstrong, D. S.; Measday, D. F.; Noble, A. J.; Stanislaus, S.; Harston, M. R.; Aniol, K. A.; Horváth, D.

    1990-01-01

    The transfer of negative pions from pionic hydrogen to deuterium has been investigated in gas mixtures of H2 and D2 as a function of the D2 concentration (C). The concentration dependence of the transfer rate was fitted using a phenomenological model with two parameters. For C-->∞ (32+/-3)% of the pions undergo transfer. The fitted parameters reflect the ratio of pion capture to pion transfer in collisions of pionic hydrogen with protons or deuterons. No pressure dependence for pion transfer was found.

  19. Laser induced neutron production by explosion of the deuterium clusters

    SciTech Connect

    Holkundkar, Amol R.; Mishra, Gaurav Gupta, N. K.

    2014-01-15

    The high energy deuterium ions serve as compact source of neutrons when fused with either deuterium or tritium atoms. In view of this, the explosion of the deuterium clusters under the influence of the laser pulse with intensity ranging from 10{sup 15} to 10{sup 19} W/cm{sup 2} is being studied along with the effect of the cluster radius and inter-cluster distance. The objective of this article is to study the efficiency of the deuterium cluster as a compact source of neutrons under various laser and cluster parameters. It is being observed that the cluster density (number of clusters per unit volume) is quite important to gain high neutron yield.

  20. Measuring the primordial deuterium abundance during the cosmic dark ages.

    PubMed

    Sigurdson, Kris; Furlanetto, Steven R

    2006-09-01

    We discuss how measurements of fluctuations in the absorption of cosmic microwave background photons by neutral gas at redshifts z approximately 7-200 could reveal the primordial deuterium abundance of the Universe. The strength of the cross-correlation of brightness-temperature fluctuations in the redshifted 21-cm line of hydrogen with those in the redshifted 92-cm line of deuterium is proportional to the value of the deuterium-to-hydrogen ratio [D/H] fixed during big bang nucleosynthesis. Although challenging, this measurement would provide the cleanest possible determination of [D/H], free from contamination by structure formation processes at lower redshifts. We additionally report our result for the thermal spin-change cross section in deuterium-hydrogen scattering. PMID:17026353

  1. Cytology is advanced by studying effects of deuterium environment

    NASA Technical Reports Server (NTRS)

    Bose, S.; Crespi, H. L.; Flaumenhaft, E.; Katz, J. J.

    1967-01-01

    Research of deuterium effects on biological systems shows deuteriation is not incompatible with life. With the successful cultivation of deuteriated bacteria, work is now being done on extraction of deuterio-compounds from bacteria.

  2. Deuterium permeation through erbium oxide coatings on RAFM steels by a dip-coating technique

    NASA Astrophysics Data System (ADS)

    Chikada, Takumi; Naitoh, Shunya; Suzuki, Akihiro; Terai, Takayuki; Tanaka, Teruya; Muroga, Takeo

    2013-11-01

    A tritium permeation barrier is a promising solution for the problems of tritium loss and radiological safety in fusion blanket systems. In recent years, erbium oxide coatings have shown remarkable permeation reduction factors. One of the remaining issues for the coatings is the establishment of plant-scale fabrication. In this study, erbium oxide thin films have been fabricated by a dip-coating technique, which has the potential to coat a complex-shaped substrate, and deuterium permeation behavior in the coatings has been examined. Crack-free coatings were formed on a reduced activation ferritic/martensitic steel F82H substrate by use of a withdrawal speed of 1.0-1.4 mm s-1 and a heat-treatment process in hydrogen with moisture. In deuterium permeation experiments, a 0.2-μm-thick coating on both sides of the substrate showed a reduction factor of 600-700 in comparison with a F82H substrate below 873 K; however, the coating degraded at above 923 K because of crack formation. A double-coated sample indicated a reduction factor of up to 2000 and did not degrade at up to 923 K. The driving pressure dependence of the deuterium permeation flux indicated that the permeation tended to be limited by surface reactions at low temperatures. Optimization of the number of layers has the possibility to reduce degradation at high temperatures while maintaining high permeation reduction factors.

  3. Deuterium ordering found in new ferroelectric compound Co2(OD)3Cl

    NASA Astrophysics Data System (ADS)

    Meng, Dong-Dong; Zheng, Xu-Guang; Liu, Xiao-Dong; Xu, Xing-Liang; Guo, Qi-Xin

    2015-07-01

    A detailed temperature-dependent Raman spectroscopic study revealed a new type of deuterium-order ferroelectrics in a geometrically frustrated magnet Co2(OD)3Cl at Tɛ = 229 K. Significant changes in the parameters of the Raman vibration modes were observed near Tɛ, suggesting a strong phonon-charge coupling. Additional asymmetric phonon bands appeared below around Tɛ, which are consistently interpreted by phonon folding processes due to a small local structural change resulting from the ordering of deuterium. The wavenumber and intensity changes of the Raman-active modes, as well as the normalized intensities of the additional bands, all follow a power-law fit Δω, ΔI, I ∝ (1 - T/TC)2β, wherein TC = 230 K ˜ Tɛ and β = 0.35(2), clearly demonstrating an ordering process below Tɛ. The critical exponent is reminiscent of a second order transition. Our study presents a rare and new type of multiferroic material with ferroelectricity arising from the deuterium ordering in geometrically frustrated magnets.

  4. Mass-Dependent and -Independent Fractionation of Mercury Isotope during Gas-Phase Oxidation of Elemental Mercury Vapor by Atomic Cl and Br.

    PubMed

    Sun, Guangyi; Sommar, Jonas; Feng, Xinbin; Lin, Che-Jen; Ge, Maofa; Wang, Weigang; Yin, Runsheng; Fu, Xuewu; Shang, Lihai

    2016-09-01

    This study presents the first measurement of Hg stable isotope fractionation during gas-phase oxidation of Hg(0) vapor by halogen atoms (Cl(•), Br(•)) in the laboratory at 750 ± 1 Torr and 298 ± 3 K. Using a relative rate technique, the rate coefficients for Hg(0)+Cl(•) and Hg(0)+Br(•) reactions are determined to be (1.8 ± 0.5) × 10(-11) and (1.6 ± 0.8) × 10(-12) cm(3) molecule(-1) s(-1), respectively. Results show that heavier isotopes are preferentially enriched in the remaining Hg(0) during Cl(•) initiated oxidation, whereas being enriched in the product during oxidation by Br(•). The fractionation factors for (202)Hg/(198)Hg during the Cl(•) and Br(•) initiated oxidations are α(202/198) = 0.99941 ± 0.00006 (2σ) and 1.00074 ± 0.00014 (2σ), respectively. A Δ(199)Hg/Δ(201)Hg ratio of 1.64 ± 0.30 (2σ) during oxidation of Hg(0) by Br atoms suggests that Hg-MIF is introduced by the nuclear volume effect (NVE). In contrast, the Hg(0) + Cl(•) reaction produces a Δ(199)Hg/Δ(201)Hg-slope of 1.89 ± 0.18 (2σ), which in addition to a high degree of odd-mass-number isotope MIF suggests impacts from MIF effects other than NVE. This reaction also exhibits significant MIF of (200)Hg (Δ(200)Hg, up to -0.17‰ in the reactant) and is the first physicochemical process identified to trigger (200)Hg anomalies that are frequently detected in atmospheric samples. PMID:27501307

  5. The Prognostic Value of the Left Ventricular Ejection Fraction Is Dependent upon the Severity of Mitral Regurgitation in Patients with Acute Myocardial Infarction

    PubMed Central

    Cho, Jung Sun; Youn, Ho-Joong; Her, Sung-Ho; Park, Maen Won; Kim, Chan Joon; Park, Gyung-Min; Cho, Jae Yeong; Ahn, Youngkeun; Kim, Kye Hun; Park, Jong Chun; Seung, Ki Bae; Cho, Myeong Chan; Kim, Chong Jin; Kim, Young Jo; Han, Kyoo Rok; Kim, Hyo Soo

    2015-01-01

    The prognostic value of the left ventricle ejection fraction (LVEF) after acute myocardial infarction (AMI) has been questioned even though it is an accurate marker of left ventricle (LV) systolic dysfunction. This study aimed to examine the prognostic impact of LVEF in patients with AMI with or without high-grade mitral regurgitation (MR). A total of 15,097 patients with AMI who received echocardiography were registered in the Korean Acute Myocardial Infarction Registry (KAMIR) between January 2005 and July 2011. Patients with low-grade MR (grades 0-2) and high-grade MR (grades 3-4) were divided into the following two sub-groups according to LVEF: LVEF ≤ 40% (n = 2,422 and 197, respectively) and LVEF > 40% (n = 12,252 and 226, respectively). The primary endpoints were major adverse cardiac events (MACE), cardiac death, and all-cause death during the first year after registration. Independent predictors of mortality in the multivariate analysis in AMI patients with low-grade MR were age ≥ 75 yr, Killip class ≥ III, N-terminal pro-B-type natriuretic peptide > 4,000 pg/mL, high-sensitivity C-reactive protein ≥ 2.59 mg/L, LVEF ≤ 40%, estimated glomerular filtration rate (eGFR), and percutaneous coronary intervention (PCI). However, PCI was an independent predictor in AMI patients with high-grade MR. No differences in primary endpoints between AMI patients with high-grade MR (grades 3-4) and EF ≤ 40% or EF > 40% were noted. MR is a predictor of a poor outcome regardless of ejection fraction. LVEF is an inadequate method to evaluate contractile function of the ischemic heart in the face of significant MR. PMID:26130953

  6. Pharmaco-thermodynamics of deuterium-induced oedema in living rat brain via 1H2O MRI: implications for boron neutron capture therapy of malignant brain tumours

    NASA Astrophysics Data System (ADS)

    Medina, Daniel C.; Li, Xin; Springer, Charles S., Jr.

    2005-05-01

    In addition to its common usage as a tracer in metabolic and physiological studies, deuterium possesses anti-tumoural activity and confers protection against γ-irradiation. A more recent interest in deuterium emanates from the search for alternatives capable of improving neutron penetrance whilst reducing healthy tissue radiation dose deposition in boron neutron capture therapy of malignant brain tumours. Despite this potential clinical application, deuterium induces brain oedema, which is detrimental to neutron capture therapy. In this study, five adult male rats were titrated with deuterated drinking water while brain oedema was monitored via water proton magnetic resonance imaging. This report concludes that deuterium, as well as deuterium-induced brain oedema, possesses a uniform brain bio-distribution. At a steady-state blood fluid deuteration value of 16%, when the deuterium isotope fraction in drinking water was 25%, a mean oedematous volume change of 9 ± 2% (p-value <0.001) was observed in the rat brain—this may account for neurological and behavioural abnormalities found in mammals drinking highly deuterated water. In addition to characterizing the pharmaco-thermodynamics of deuterium-induced oedema, this report also estimates the impact of oedema on thermal neutron enhancement and effective dose reduction factors using simple linear transport calculations. While body fluid deuteration enhances thermal neutron flux penetrance and reduces dose deposition, oedema has the opposite effect because it increases the volume of interest, e.g., the brain volume. Thermal neutron enhancement and effective dose reduction factors could be reduced by as much as ~10% in the presence of a 9% water volume increase (oedema). All three authors have contributed equally to this work.

  7. Combinatorial synthesis of deuterium-enriched (S)-oxybutynin.

    PubMed

    Li, Feng; Jiang, Wenfeng; Czarnik, Anthony W; Li, Wenbao

    2016-08-01

    The concept of deuterium enrichment has gained more attention due to its advantages in the studies of clinical pharmacokinetics and metabolic profiles. In addition, it is cost and time efficient to develop deuterium-enriched drugs. Herein we built a combinatorial library of deuterated (S)-oxybutynins which all 8 D-compounds were characterized by MS, [Formula: see text] NMR and [Formula: see text]C NMR. PMID:26852022

  8. Absolute cross section for recoil detection of deuterium

    NASA Astrophysics Data System (ADS)

    Besenbacher, F.; Stensgaard, I.; Vase, P.

    1986-04-01

    The D( 4He, D) 4He cross section used for recoil detection of deuterium (D) has been calibrated on an absolute scale against the cross section of the D( 3He, α)p nuclear reaction which is often used for D profiling. For 4He energies ranging from 0.8 to ~1.8 MeV. the D( 4He, D) 4He cross section varies only slightly with incident energy and recoil angle θ (for 0° ⩽ 8 ⩽ 35°) and has a value of ~ 500 mb/sr which is significantly higher than the ~ 65 mb/sr c.m.s. cross section of the D( 3He, α)p nuclear reaction. For 4He energies ranging from ~ 1.9 to ~ 2.3 MeV, the D( 4He,D) 4He cross section exhibits a fairly narrow resonance peak (fwhm ~ 70 keV), with a maximum value (for θ = 0°) of ~ 8.5 b/sr, corresponding to a 4He energy of ~ 2130 keV. The large values of the cross section in connection with the described energy dependence makes the use of forward-recoil detection of D attractive for many purposes, e.g., D Jepth profiling (with an extreme gain in sensitivity), absolute concentration or coverage measurements, and lattice-location experiments by transmission channeling.

  9. Complete photo-fragmentation of the deuterium molecule

    SciTech Connect

    Weber, Thorsten; Czasch, Achim O.; Jagutzki, Ottmar; Muller, Alkis K.; Mergel, Volker; Kheifets, A.; Rotenberg, Eli; Meigs, George; Prior, Mike H.; Daveau, Sebastian; Landers, Allen; Cocke, C.L.; Osipov, Timur; Diez Muino, Ricardo; Schmidt-Bocking, Horst; Dorner, Reinhard

    2004-05-13

    All properties of molecules, from binding and excitation energies to their geometry, are determined by the highly correlated initial state wavefunction of the electrons and nuclei. Perhaps surprisingly, details of these correlations can be revealed by studying the break-up of these systems into their constituents. The fragmentation might be initiated by the absorption of a single photon [1, 2, 3, 4, 5, 6], collision with a charged particle [7, 8] or exposure to a strong laser pulse [9, 10]. If the exciting interaction is sufficiently understood, one can use the fragmentation process as a tool to learn about the bound initial state [11, 12]. However, often the interaction and the fragment motions pose formidable challenges to quantum theory [13, 14, 15]. Here we report the coincident measurement of the momenta of both nuclei and both electrons from the single photon induced fragmentation of the deuterium molecule. The results reveal that the correlated motion of the electrons is strongly dependent on the inter-nuclear separation in the molecular ground state at the instant of photon absorption.

  10. Hydrogen, deuterium and tritium in palladium: An eleastic constants study

    SciTech Connect

    Bach, H. T.; Schwarz, R. B.; Tuggle, D. G.

    2004-01-01

    We have used resonant ultrasound spectroscopy to measure the three independent elastic constants of Pd-H, Pd-D, and Pd-T single crystal at 300K as a junction of hydrogen, deuterium, and tritium concentration, respectively. The addition of interstitial H (D, or T) atoms, located at (0, 1/2, 0) in the fcc Pd lattice, affects all three elastic constants C, C{sub 44}, and B. In the mixed (a+{beta}) phase, and with increasing H isotope, the shear modulus C' shows an abnormal softening whereas C{sub 44} and B do not. This is explained in terms of Zener-type anelastic relaxations affecting the shape of the hydride phases in the coherent ({alpha}+{beta}) two-phase mixture In the single {beta}-phase, C' shows a strong isotope dependence whereas C{sub 44} and B show none. This behavior is explained in terms of differences in the excitation of optical phonons. In Pd-T, {sup 3}He is produced by the radioactive decay of tritium. We have measured in situ the swelling and the change in the elastic constants in Pd-T as a function of aging time. Aging ({sup 3}He formation) affects all three elastic constants. These measurements are being used to understand the early stages of {sup 3}H-{sup 3}He clusterformation in aged Pd-T crystal.

  11. Advanced Deuterium Fusion Rocket Propulsion for Manned Deep Space Missions

    NASA Astrophysics Data System (ADS)

    Winterberg, F.

    Excluding speculations about future breakthrough discoveries in physics, it is shown that with what is at present known, and also what is technically feasible, manned space flight to the limits of the solar system and beyond deep into the Oort cloud is quite possible. Using deuterium as the rocket fuel of choice, abundantly available on the comets of the Oort cloud, rockets driven by deuterium fusion can there be refuelled. To obtain a high thrust with high specific impulse favours the propulsion by deuterium micro-bombs, and it is shown that the ignition of deuterium micro-bombs is possible by intense GeV proton beams, generated in space by using the entire spacecraft as a magnetically insulated billion volt capacitor. The cost to develop this kind of a propulsion system in space would be very high, but it can also be developed on Earth by a magnetically insulated Super Marx Generator. Since the ignition of deuterium is theoretically possible with the Super Marx Generator, making obsolete the ignition of deuterium-tritium with a laser, where 80% of the energy goes into neutrons, this would also mean a breakthrough in fusion research, and therefore would justify the large development costs.

  12. Deuterium retention in ITER-grade austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Nemanič, Vincenc; Žumer, Marko; Zajec, Bojan

    2008-11-01

    In view of the construction of ITER, it is essential to confirm that the retention of tritium by the large interior surface area of stainless steel will not become an issue for safety or operating inventory reasons. Retention of deuterium in ITER-grade austenitic stainless steel samples was studied during t = 24 h exposures to pure gaseous deuterium at p = 0.01 mbar and 0.1 mbar and T = 100 °C, 250 °C and 400 °C, respectively. The required high sensitivity for distinguishing hydrogen isotopes involved in the process (H2, HD and D2) was gained after suppression of the native hydrogen concentration by a thermal treatment at T = 400 °C for t = 200 h. The quantity of retained deuterium was determined by measuring the absolute pressure change during the deuterium exposure and subsequent mass spectrometry revealing an intense isotope exchange reaction. The retained amount of 2.6 × 1016 D cm-2 was the highest at T = 400 °C and p = 0.1 mbar and noticeably less at lower deuterium pressure and temperature. Our results, when compared with similar tritium exposures, do not exceed the limits set in the generic safety analysis for the ITER. They manifest that an extremely high sensitivity for deuterium absorption and release can be gained with a precise pressure measuring technique, otherwise attributed exclusively to tritium scintillation methods.

  13. Equations of state for hydrogen and deuterium.

    SciTech Connect

    Kerley, Gerald Irwin (Kerley Technical Services, Appomattox, VA)

    2003-12-01

    This report describes the complete revision of a deuterium equation of state (EOS) model published in 1972. It uses the same general approach as the 1972 EOS, i.e., the so-called 'chemical model,' but incorporates a number of theoretical advances that have taken place during the past thirty years. Three phases are included: a molecular solid, an atomic solid, and a fluid phase consisting of both molecular and atomic species. Ionization and the insulator-metal transition are also included. The most important improvements are in the liquid perturbation theory, the treatment of molecular vibrations and rotations, and the ionization equilibrium and mixture models. In addition, new experimental data and theoretical calculations are used to calibrate certain model parameters, notably the zero-Kelvin isotherms for the molecular and atomic solids, and the quantum corrections to the liquid phase. The report gives a general overview of the model, followed by detailed discussions of the most important theoretical issues and extensive comparisons with the many experimental data that have been obtained during the last thirty years. Questions about the validity of the chemical model are also considered. Implications for modeling the 'giant planets' are also discussed.

  14. Deuterium on Venus: Observations from Earth

    NASA Technical Reports Server (NTRS)

    Lutz, Barry L.; Debergh, C.; Bezard, B.; Owen, T.; Crisp, D.; Maillard, J.-P.

    1991-01-01

    In view of the importance of the deuterium-to-hydrogen ratio in understanding the evolutionary scenario of planetary atmospheres and its relationship to understanding the evolution of our own Earth, we undertook a series of observations designed to resolve previous observational conflicts. We observed the dark side of Venus in the 2.3 micron spectral region in search of both H2O and HDO, which would provide us with the D/H ratio in Venus' atmosphere. We identified a large number of molecular lines in the region, belonging to both molecules, and, using synthetic spectral techniques, obtained mixing ratios of 34 plus or minus 10 ppm and 1.3 plus or minus 0.2 ppm for H2O and HDO, respectively. These mixing ratios yield a D/H ratio for Venus of D/H equals 1.9 plus or minus 0.6 times 10 (exp 12) and 120 plus or minus 40 times the telluric ratio. Although the detailed interpretation is difficult, our observations confirm that the Pioneer Venus Orbiter results and establish that indeed Venus had a period in its early history in which it was very wet, perhaps not unlike the early wet period that seems to have been present on Mars, and that, in contrast to Earth, lost much of its water over geologic time.

  15. Dependence of intake fraction on release location in a multi-media framework: A case study of four contaminants in North America

    SciTech Connect

    MacLeod, Matthew; Bennett, Deborah H.; Perem, Merike; Maddalena, Randy L.; M cKone, Thomas E.; Mackay, Don

    2003-03-01

    The extent of human exposure to persistent anthropogenic environmental contaminants is a complex function of the amount of chemical emitted, its physico-chemical properties and reactivity, the nature of the environment, and the characteristics of the pathways for human exposure, such as inhalation, intake of food and water and dermal contact. For some chemicals, the location of emissions relative to areas of high population density or intense food production may also be an important factor. The relative importance of these variables is explored using the regionally segmented BETR North America contaminant fate model and data for food production patterns and population density for North America. The model is applied to four contaminants emitted to air: benzene, carbon tetrachloride, benzo[a]pyrene and 2,3,7,8-tetrachlorodibenzo dioxin. The total continental intake fraction (iF), relating exposure quantity to emission quantity, is employed as a metric for assessing population exposure to environmental contaminants. The results show that the use of continentally averaged parameters for population density and food production provides an accurate estimate of the median of iF calculated for emissions in individual regions, however iF can range from this median by up to 3 orders of magnitude, especially for chemicals transferred to humans through the food pathway. The location of population relative to food production and emissions of chemicals are important variables that should be considered in assessing the public health implications of chemical emissions.

  16. Gas-pressure dependence of charge-state fractions and mean charges of 1.4 MeV/u-uranium ions stripped in molecular hydrogen

    NASA Astrophysics Data System (ADS)

    Shevelko, V. P.; Winckler, N.; Tolstikhina, I. Yu.

    2016-06-01

    Using a recently created BREIT computer code (Balance Rate Equations for Ion Transportation), evolutions of the charge-state fractions Fq (x) and equilibrium mean charge states q bar are calculated for stripping of 1.4 MeV/u-U4+ ions in H2 gas for target thicknesses x ⩽ 100 μg /cm2 (⩽ 3 ·1019molecule /cm2) and gas pressures 10-4 ⩽ P ⩽ 500 mbar. Calculations of the non-equilibrium Fq (x) and equilibrium Fq0 distributions for ion charges 4 ⩽ q ⩽ 40 are performed by solving the balance (rate) equations with account for the multi-electron processes and the target-density effect. Calculated equilibrium mean charge state increases from q bar ≈ 27.6 at P =10-4 mbar to its saturated (maximum) value of q bar ≈ 32.7 at pressures P≳ 250 mbar while the equilibrium target thickness xeq increases from 20 to 50 μg /cm2 (from 0.6 to 1.5 in units of 1019molecule /cm2) in the H2-pressure range considered. From the present calculations it is concluded that the maximum mean charge state q bar which can be achieved in stripping of 1.4 MeV/u-U4+ ions in H2 gas is about q bar ≈ 33 at a gas pressure P≳ 250 mbar.

  17. Deuterium retention and morphological modifications of the surface in five grades of tungsten after deuterium plasma exposure

    NASA Astrophysics Data System (ADS)

    Balden, M.; Manhard, A.; Elgeti, S.

    2014-09-01

    Five tungsten (W) grades were simultaneously exposed to deuterium (D) plasma with 1020 D/(m2 s) of 38 eV/D up to 1026 D/m2 at 500 K specimen temperature. The D inventories and their depth profiles within the topmost 12 μm were determined by nuclear reaction analysis (D(3He, p)α). Morphological modifications at and below the surface were analysed by confocal laser scanning microscopy and scanning electron microscopy assisted by focused ion beam cross-sectioning. The observed variation of the D inventory by more than one order of magnitude (0.5-15 × 1020 D/m2) is attributed only to the different properties of each W grade. Spherical blisters and stepped flat-topped extrusions are observed depending on the W grade. These modifications are interpreted as an indication for hydrogen loading-induced damaging. The exposure conditions and W grades were chosen to allow a comparison between published data sets.

  18. Levels and Age Dependency of Neurofilament Light and Glial Fibrillary Acidic Protein in Healthy Individuals and Their Relation to the Brain Parenchymal Fraction

    PubMed Central

    Vågberg, Mattias; Norgren, Niklas; Dring, Ann; Lindqvist, Thomas; Birgander, Richard; Zetterberg, Henrik; Svenningsson, Anders

    2015-01-01

    Background Neurofilament light (NFL) and Glial Fibrillary Acidic Protein (GFAP) are integral parts of the axonal and astrocytal cytoskeletons respectively and are released into the cerebrospinal fluid (CSF) in cases of cellular damage. In order to interpret the levels of these biomarkers in disease states, knowledge on normal levels in the healthy is required. Another biomarker for neurodegeneration is brain atrophy, commonly measured as brain parenchymal fraction (BPF) using magnetic resonance imaging (MRI). Potential correlations between levels of NFL, GFAP and BPF in healthy individuals have not been investigated. Objectives To present levels of NFL and GFAP in healthy individuals stratified for age, and investigate the correlation between them as well as their correlation with BPF. Methods The CSF was analysed in 53 healthy volunteers aged 21 to 70 (1 sample missing for GFAP analysis) and 48 of the volunteers underwent determination of BPF using MRI. Results Mean (±SD) NFL was 355 ng/L (±214), mean GFAP was 421 ng/L (±129) and mean BPF was 0.867 (±0.035). All three biomarkers correlated with age. NFL also correlated with both GFAP and BPF. When controlled for age, only the correlation between NFL and GFAP retained statistical significance. Conclusions This study presents data on age-stratified levels of NFL and GFAP in the CSF of healthy individuals. There is a correlation between levels of NFL and GFAP and both increase with age. A correlation between NFL and BPF was also found, but did not retain statistical significance if controlled for age. PMID:26317831

  19. Balloon-Borne Submillimeter Polarimetry of the Vela C Molecular Cloud: Systematic Dependence of Polarization Fraction on Column Density and Local Polarization-Angle Dispersion

    NASA Astrophysics Data System (ADS)

    Fissel, Laura M.; Ade, Peter A. R.; Angilè, Francesco E.; Ashton, Peter; Benton, Steven J.; Devlin, Mark J.; Dober, Bradley; Fukui, Yasuo; Galitzki, Nicholas; Gandilo, Natalie N.; Klein, Jeffrey; Korotkov, Andrei L.; Li, Zhi-Yun; Martin, Peter G.; Matthews, Tristan G.; Moncelsi, Lorenzo; Nakamura, Fumitaka; Netterfield, Calvin B.; Novak, Giles; Pascale, Enzo; Poidevin, Frédérick; Santos, Fabio P.; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A.; Diego Soler, Juan; Thomas, Nicholas E.; Tucker, Carole E.; Tucker, Gregory S.; Ward-Thompson, Derek

    2016-06-01

    We present results for Vela C obtained during the 2012 flight of the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry. We mapped polarized intensity across almost the entire extent of this giant molecular cloud, in bands centered at 250, 350, and 500 μm. In this initial paper, we show our 500 μm data smoothed to a resolution of 2.‧5 (approximately 0.5 pc). We show that the mean level of the fractional polarization p and most of its spatial variations can be accounted for using an empirical three-parameter power-law fit, p \\propto {{\\boldsymbol{N}}}-0.45 {{\\boldsymbol{S}}}-0.60, where N is the hydrogen column density and S is the polarization-angle dispersion on 0.5 pc scales. The decrease of p with increasing S is expected because changes in the magnetic field direction within the cloud volume sampled by each measurement will lead to cancellation of polarization signals. The decrease of p with increasing N might be caused by the same effect, if magnetic field disorder increases for high column density sightlines. Alternatively, the intrinsic polarization efficiency of the dust grain population might be lower for material along higher density sightlines. We find no significant correlation between N and S. Comparison of observed submillimeter polarization maps with synthetic polarization maps derived from numerical simulations provides a promising method for testing star formation theories. Realistic simulations should allow for the possibility of variable intrinsic polarization efficiency. The measured levels of correlation among p, N, and S provide points of comparison between observations and simulations.

  20. Deuterium absorption from the D{sub 2}O exposure of oxidized 4H-SiC (0001), (0001{sup ¯}), and (112{sup ¯}0) surfaces

    SciTech Connect

    Liu, Gang; Xu, Can; Feldman, Leonard C.; Yakshinskiy, Boris; Wielunski, Leszek; Gustafsson, Torgny; Bloch, Joseph; Dhar, Sarit

    2015-03-23

    We report results on deuterium absorption on several oxidized 4H-SiC surfaces following D{sub 2}O vapor absorption. Absorption at the oxide/semiconductor interface is strongly face dependent with an order of magnitude more deuterium on the C-face and a-face than on the Si-face, in contrast to the bulk of the oxides which show essentially no face dependence. Annealing in NO gas produces a large reduction in interfacial deuterium absorption in all cases. The reduction of the positive charge at the interface scales linearly with the interface D content. These results also scale with the variation in interface trap density (D{sub it}) and mobility on the three faces after wet oxidation annealing.

  1. Inhibition of IgE-dependent Mouse Triphasic Cutaneous Reaction by a Boiling Water Fraction Separated from Mycelium of Phellinus linteus

    PubMed Central

    2005-01-01

    Phellinus linteus, a mushroom, contains constituents that exhibit potent antitumor effects through activating immune cells. Recently, anti-inflammatory and anti-allergic properties of P. linteus extracts have also been implicated. In the present study, therefore, we separated the constituents of mycelium of P. linteus into five fractions—chloroform-soluble (CF), ethyl acetate-soluble (EA), methanol-soluble (AE), water-soluble (WA) and boiling water-soluble (BW) fractions—and examined their suppressive effects on the IgE-dependent mouse triphasic cutaneous reaction. The triphasic reaction was induced in the ear of BALB/c mice passively sensitized with anti-dinitrophenol IgE by painting with 2,4-dinitrofluorobenzene 24 h later. Ear swelling appeared triphasically with peak responses at 1 h, 24 h and 8 days after the challenge. ME, WA and BW given orally at a dose of 100 mg kg−1 significantly inhibited the first and second phase ear swelling, and BW also inhibited the third phase response. CF only inhibited the second phase. The inhibition by BW was the most potent and almost dose-dependent at doses of 30–300 mg kg−1. BW also inhibited vascular permeability increase caused by passive cutaneous anaphylaxis and histamine, and ear swelling caused by tumor necrosis factor-α. In contrast, BW apparently potentiated the production of interleukin-4 and interferon-γ from anti-CD3-stimulated mouse splenocytes. These results indicate that BW derived from mycelium of P. linteus contains some constituents with anti-allergic as well as immunopotentiating properties. PMID:16136215

  2. Chemical response of lithiated graphite with deuterium irradiation

    SciTech Connect

    Taylor, C. N.; Heim, B.; Allain, J. P.

    2011-03-01

    Lithium wall conditioning has been found to enhance plasma performance for graphite walled fusion devices such as TFTR, CDX-U, T-11M, TJ-II and NSTX. Among observed plasma enhancements is a reduction in edge density and reduced deuterium recycling. The mechanism by which lithiated graphite retains deuterium is largely unknown. Under controlled laboratory conditions, X-ray photoelectron spectroscopy (XPS) is used to observe the chemical changes that occur on ATJ graphite after lithium deposition. The chemical state of lithiated graphite is found to change upon deuterium irradiation indicating the formation Li-O-D, manifest at 532.9 {+-} 0.6 eV. Lithium-deuterium interactions are also manifest in the C 1s photoelectron energy range and show Li-C-D interactions at 291.2 {+-} 0.6 eV. Post-mortem NSTX tiles that have been exposed to air upon extraction are cleaned and examined, revealing the chemical archaeology that formed during NSTX operations. XPS spectra show strong correlation ({+-} 0.3 eV) in Li-O-D and Li-O peaks from post-mortem and control experiments, thus validating offline experiments. We report findings that show that deuterium is found to interact with lithium after lithium has already reacted with carbon and oxygen.

  3. Deuterium trapping and release in JET ITER-like wall divertor tiles

    NASA Astrophysics Data System (ADS)

    Likonen, J.; Heinola, K.; De Backer, A.; Koivuranta, S.; Hakola, A.; Ayres, C. F.; Baron-Wiechec, A.; Coad, P.; Matthews, G. F.; Mayer, M.; Widdowson, A.; Contributors, JET

    2016-02-01

    A selected set of samples from JET-ILW divertor tiles exposed in 2011-2012 has been analysed using thermal desorption spectrometry (TDS). The highest amount of deuterium was found on the regions with the thickest deposited layers, i.e. on the horizontal (apron) part and on the top part of Tile 1, which resides deep in the scrape-off layer. Outer divertor Tiles 6, 7 and 8 had nearly an order of magnitude less deuterium. The co-deposited layers on the JET tiles and the W coatings contain C, O and Ni impurities which may change the desorption properties. The D2 signals in the TDS spectra were convoluted and the positions of the peaks were compared with the Be and C amounts but no correlations between them were found. The remaining fractions of D in the analysed samples at ITER baking temperature 350 °C are rather high implying that co-deposited films may be difficult to be de-tritiated.

  4. Evidence of the Timing and Rate of Uplift of Central Peruvian Andes from Deuterium Isotopes in Volcanic Glass

    NASA Astrophysics Data System (ADS)

    Winton, R.; Saylor, J. E.; Horton, B. K.

    2013-12-01

    The uplift history of the Central Andean Plateau (CAP) presents challenges to paleoelevation research with both the rate and timing of uplift debated. Two end-member models have been proposed: 1) gradual surface uplift driven primarily by tectonic shortening (e.g., Barnes and Ehlers, 2009); and 2) rapid uplift in the late Miocene driven primarily by convective removal of dense lower lithosphere (e.g., Garzione et al., 2008). Recently acquired stable isotope and paleotemperature data present a more complex picture of CAP uplift, with multiple spatially and temporally separate uplift pulses (e.g., Quade et al., 2011; Saylor et al., 2012; Leier et al., 2013). In particular, Quade et al. (2011) and Saylor et al. (2012) suggest that the southern and northern CAP may have been uplifted in the early Oligocene and early Miocene, respectively; earlier than the central Altiplano implying an 'edge-to-center' progression of uplift. Determining the rates, timing, and spatial patterns of uplift is hindered by the complex array of factors that influence paleoelevation proxies. While the isotopic composition in rising air masses, precipitation and surface water shows a systematic depletion of 18O and D at higher elevations, this lapse rate may have varied through time due to changes in topography or climate (e.g., Insel et al., 2012). Further complications arise when using carbonates as a proxy record because the fractionation factor between surface water and carbonate depends on the temperature of crystallization which is, in turn, also dependent primarily on elevation. Here we present new deuterium isotopic analyses of volcanic glass in the Ayacucho Basin (13.15° S, 74.2° W), central Peru. The Ayacucho Basin is located north of the Altiplano at 2.7-3.7 km elevation, north of the Abancay Deflection. Volcanic glass is well suited for this study because once hydrated, the isotopic composition of the waters of hydration remains distinct from the isotopic composition of modern

  5. A dosimetry study of deuterium-deuterium neutron generator-based in vivo neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Sowers, Daniel A.

    A neutron irradiation cavity for in vivo Neutron Activation Analysis (IVNAA) to detect manganese, aluminum, and other potentially toxic elements in human hand bone has been designed and its dosimetric specifications measured. The neutron source is a customized deuterium-deuterium neutron generator which produces neutrons at 2.45 MeV by the fusion reaction 2H(d, n)3He at a calculated flux of 7 x 108 +/-30% s-1. A moderator/reflector/shielding (5 cm high density polyethylene (HDPE), 5.3 cm graphite & 5.7 cm borated HDPE) assembly has been designed and built to maximize the thermal neutron flux inside the hand irradiation cavity and to reduce the extremity dose and effective dose to the human subject. Lead sheets are used to attenuate bremsstrahlung x rays and activation gammas. A Monte Carlo simulation (MCNP6) was used to model the system and calculate extremity dose. The extremity dose was measured with neutron and photon sensitive film badges and Fuji electronic pocket dosimeter (EPD). The neutron ambient dose outside the shielding was measured by Fuji NSN3, and photon dose by a Bicron MicroREM scintillator. Neutron extremity dose was calculated to be 32.3 mSv using MCNP6 simulations given a 10 min IVNAA measurement of manganese. Measurements by EPD and film badge indicate hand dose to be 31.7 +/- 0.8 mSv for neutron and 4.2 +/- 0.2 mSv for photon for 10 mins; whole body effective dose was calculated conservatively to be 0.052 mSv. Experimental values closely match values obtained from MCNP6 simulations. These are acceptable doses to apply the technology for a manganese toxicity study in a human population.

  6. A Dosimetry Study of Deuterium-Deuterium Neutron Generator-based In Vivo Neutron Activation Analysis.

    PubMed

    Sowers, Daniel; Liu, Yingzi; Mostafaei, Farshad; Blake, Scott; Nie, Linda H

    2015-12-01

    A neutron irradiation cavity for in vivo neutron activation analysis (IVNAA) to detect manganese, aluminum, and other potentially toxic elements in human hand bone has been designed and its dosimetric specifications measured. The neutron source is a customized deuterium-deuterium neutron generator that produces neutrons at 2.45 MeV by the fusion reaction 2H(d, n)3He at a calculated flux of 7 × 10(8) ± 30% s(-1). A moderator/reflector/shielding [5 cm high density polyethylene (HDPE), 5.3 cm graphite and 5.7 cm borated (HDPE)] assembly has been designed and built to maximize the thermal neutron flux inside the hand irradiation cavity and to reduce the extremity dose and effective dose to the human subject. Lead sheets are used to attenuate bremsstrahlung x rays and activation gammas. A Monte Carlo simulation (MCNP6) was used to model the system and calculate extremity dose. The extremity dose was measured with neutron and photon sensitive film badges and Fuji electronic pocket dosimeters (EPD). The neutron ambient dose outside the shielding was measured by Fuji NSN3, and the photon dose was measured by a Bicron MicroREM scintillator. Neutron extremity dose was calculated to be 32.3 mSv using MCNP6 simulations given a 10-min IVNAA measurement of manganese. Measurements by EPD and film badge indicate hand dose to be 31.7 ± 0.8 mSv for neutrons and 4.2 ± 0.2 mSv for photons for 10 min; whole body effective dose was calculated conservatively to be 0.052 mSv. Experimental values closely match values obtained from MCNP6 simulations. These are acceptable doses to apply the technology for a manganese toxicity study in a human population. PMID:26509624

  7. Cell-specific activity-dependent fractionation of layer 2/3→5B excitatory signaling in mouse auditory cortex.

    PubMed

    Joshi, Ankur; Middleton, Jason W; Anderson, Charles T; Borges, Katharine; Suter, Benjamin A; Shepherd, Gordon M G; Tzounopoulos, Thanos

    2015-02-18

    Auditory cortex (AC) layer 5B (L5B) contains both corticocollicular neurons, a type of pyramidal-tract neuron projecting to the inferior colliculus, and corticocallosal neurons, a type of intratelencephalic neuron projecting to contralateral AC. Although it is known that these neuronal types have distinct roles in auditory processing and different response properties to sound, the synaptic and intrinsic mechanisms shaping their input-output functions remain less understood. Here, we recorded in brain slices of mouse AC from retrogradely labeled corticocollicular and neighboring corticocallosal neurons in L5B. Corticocollicular neurons had, on average, lower input resistance, greater hyperpolarization-activated current (Ih), depolarized resting membrane potential, faster action potentials, initial spike doublets, and less spike-frequency adaptation. In paired recordings between single L2/3 and labeled L5B neurons, the probabilities of connection, amplitude, latency, rise time, and decay time constant of the unitary EPSC were not different for L2/3→corticocollicular and L2/3→corticocallosal connections. However, short trains of unitary EPSCs showed no synaptic depression in L2/3→corticocollicular connections, but substantial depression in L2/3→corticocallosal connections. Synaptic potentials in L2/3→corticocollicular connections decayed faster and showed less temporal summation, consistent with increased Ih in corticocollicular neurons, whereas synaptic potentials in L2/3→corticocallosal connections showed more temporal summation. Extracellular L2/3 stimulation at two different rates resulted in spiking in L5B neurons; for corticocallosal neurons the spike rate was frequency dependent, but for corticocollicular neurons it was not. Together, these findings identify cell-specific intrinsic and synaptic mechanisms that divide intracortical synaptic excitation from L2/3 to L5B into two functionally distinct pathways with different input-output functions. PMID

  8. Development of neutron spectrometer toward deuterium plasma diagnostics in LHD

    SciTech Connect

    Tomita, H.; Iwai, H.; Iguchi, T.; Kawarabayashi, J.; Isobe, M.; Konno, C.

    2010-10-15

    Neutron spectrometer based on coincident counting of associated particles has been developed for deuterium plasma diagnostics on Large Helical Device (LHD) at the National Institute for Fusion Science. Efficient detection of 2.5 MeV neutron with high energy resolution would be achievable by coincident detection of a scattered neutron and a recoiled proton associated with an elastic scattering of incident neutron in a plastic scintillator as a radiator. The calculated neutron spectra from deuterium plasma heated by neutral beam injection indicate that the energy resolution of better than 7% is required for the spectrometer to evaluate energetic deuterium confinement. By using a prototype of the proposed spectrometer, the energy resolution of 6.3% and the detection efficiency of 3.3x10{sup -7} count/neutron were experimentally demonstrated for 2.5 MeV monoenergetic neutron, respectively.

  9. Development of neutron spectrometer toward deuterium plasma diagnostics in LHD.

    PubMed

    Tomita, H; Iwai, H; Iguchi, T; Isobe, M; Kawarabayashi, J; Konno, C

    2010-10-01

    Neutron spectrometer based on coincident counting of associated particles has been developed for deuterium plasma diagnostics on Large Helical Device (LHD) at the National Institute for Fusion Science. Efficient detection of 2.5 MeV neutron with high energy resolution would be achievable by coincident detection of a scattered neutron and a recoiled proton associated with an elastic scattering of incident neutron in a plastic scintillator as a radiator. The calculated neutron spectra from deuterium plasma heated by neutral beam injection indicate that the energy resolution of better than 7% is required for the spectrometer to evaluate energetic deuterium confinement. By using a prototype of the proposed spectrometer, the energy resolution of 6.3% and the detection efficiency of 3.3×10(-7) count/neutron were experimentally demonstrated for 2.5 MeV monoenergetic neutron, respectively. PMID:21033835

  10. Deuterium content of snow cores from Sierra Nevada area

    USGS Publications Warehouse

    Friedman, I.; Smith, G.I.

    1970-01-01

    The relative deuterium content was measured on 37 snow cores collected in April 1969 in the Sierra Nevada. The deuterium content varies inversely with altitude of collection (approximately 40 per mil per 1000 meters) but is unrelated to latitude. The altitude relationship is particularly well defined west of the crest of the range but is not well defined east of the crest. However, samples from east of the crest tend to be depleted by about 10 to 15 per mil relative to samples collected at the same elevation west of the crest. We propose that the deuterium content of snow cores, collected so as to include the total winter's precipitation, can be used as a climatic indicator to compare the climate of one winter with that of another.

  11. Deuterium NMR Studies of the Structure and Dynamics of Gramicidin.

    NASA Astrophysics Data System (ADS)

    Hing, Andrew William

    1990-01-01

    The structure and dynamics of the membrane peptide gramicidin are investigated by deuterium NMR. A specific structural and dynamical question about the peptide backbone of gramicidin is investigated by deuterating the alpha carbon of the third alanine residue. Deuterium NMR experiments performed on this analog in oriented lipid bilayers indicate that the c_alpha- ^2H bond makes an angle relative to the helical axis that is in agreement with the bond angle predicted by the beta^{6.3} helical model. A second structural and dynamical question about the peptide backbone of gramicidin is investigated by deuterating the formyl group of two different analogs. Deuterium NMR experiments performed on these analogs show that the spectra of the two analogs are very similar. However, the analog possessing D-leucine as the second residue also appears to exist in a second, minor conformation which does not seem to exist for the analog possessing glycine as the second residue.

  12. Helium and deuterium implantation in tungsten at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Cipiti, B. B.; Kulcinski, G. L.

    2005-12-01

    High temperature helium and deuterium implantation on tungsten has been studied using the University of Wisconsin inertial electrostatic confinement device. Helium or deuterium ions from a plasma source were driven into polished tungsten powder metallurgy samples. Deuterium implantation did not damage the surface of the specimens at elevated temperatures (˜1200 °C). Helium implantation resulted in a porous surface structure above 700 °C. A helium fluence scan, ion energy scan, and temperature scan were all completed. With 30 keV ions, the pore formation started just below 4 × 10 16 He +/cm 2. The pore size increased and the pore density decreased with increasing fluence and temperature. The energy scan from 20 to 80 keV showed no consistent trend.

  13. Selective deuterium ion acceleration using the Vulcan petawatt laser

    NASA Astrophysics Data System (ADS)

    Krygier, A. G.; Morrison, J. T.; Kar, S.; Ahmed, H.; Alejo, A.; Clarke, R.; Fuchs, J.; Green, A.; Jung, D.; Kleinschmidt, A.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.; Freeman, R. R.

    2015-05-01

    We report on the successful demonstration of selective acceleration of deuterium ions by target-normal sheath acceleration (TNSA) with a high-energy petawatt laser. TNSA typically produces a multi-species ion beam that originates from the intrinsic hydrocarbon and water vapor contaminants on the target surface. Using the method first developed by Morrison et al. [Phys. Plasmas 19, 030707 (2012)], an ion beam with >99% deuterium ions and peak energy 14 MeV/nucleon is produced with a 200 J, 700 fs, > 10 20 W / cm 2 laser pulse by cryogenically freezing heavy water (D2O) vapor onto the rear surface of the target prior to the shot. Within the range of our detectors (0°-8.5°), we find laser-to-deuterium-ion energy conversion efficiency of 4.3% above 0.7 MeV/nucleon while a conservative estimate of the total beam gives a conversion efficiency of 9.4%.

  14. Core Deuterium Fusion and Radius Inflation in Hot Jupiters

    NASA Astrophysics Data System (ADS)

    Jaikumar, Prashanth; Rachid Ouyed

    2016-06-01

    Several laboratory-based studies have shown that the Deuterium fusion cross-section is enhanced in a solid deuterated target as compared to a gas target, attributable to enhanced mobility of deuterons in a metal lattice. As an application, we propose that, for core temperatures and compositions characterizing hot Jupiters, screened Deuterium fusion can occur deep in the interior, and show that the amount of radius inflation from this effect can be important if there is sufficient rock-ice in the core. The mechanism of screened Deuterium fusion, operating in the above temperature range, is generally consistent with the trend in radius anomaly with planetary equilibrium temperature. We also explore the trend with planetary mass using a simple analytic model.

  15. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake.

    PubMed

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Donohoe, Gregory C; Valentine, Stephen J

    2016-03-01

    Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H](3-) and [M - 5H](5-) insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å(2) and 808 ± 2 Å(2). [M - 4H](4-) ions were comprised of more compact (Ω = 676 ± 3 Å(2)) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å(2)) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H](4-) and [M - 5H](5-) ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis. PMID:26620531

  16. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake

    NASA Astrophysics Data System (ADS)

    Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Donohoe, Gregory C.; Valentine, Stephen J.

    2016-03-01

    Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H]3- and [M - 5H]5- insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å2 and 808 ± 2 Å2. [M - 4H]4- ions were comprised of more compact (Ω = 676 ± 3 Å2) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å2) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H]4- and [M - 5H]5- ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis.

  17. A study of neutron emission from a deuterium-saturated TiFe alloy at room temperature

    NASA Astrophysics Data System (ADS)

    Lobanov, V. V.; Zetkin, A. S.; Kagan, G. E.; Demin, V. B.; Mil'Man, I. I.; Siurdo, A. I.

    1991-12-01

    Experimental data are presented on neutron emission from a TiFe alloy (46.14 at. pct Fe), saturated by deuterium from the gas phase, when the alloy is held in dynamic vacuum at room temperature. The time dependences of neutron yield feature one to three peaks over the observation period (160 min), with the relative intensity of the peaks varying by more than two orders of magnitude.

  18. Release Fraction Evaluation

    SciTech Connect

    Bamberger, Judith A.; Glissmeyer, John A.

    2004-01-01

    liquid phase. Release fractions are commonly used to make conservative estimates of emissions from processes. Usually, rather gross assumptions are made in such estimates, such as the total failure of abatement equipment and the use of maximum inventory values. Consequently, it is common practice to report bounding release fraction values with single digit accuracy. The release fractions for the top of the unventilated tank ranged from 9 x 10{sup -7} to 8 x 10{sup -5} depending on the process simulated.

  19. Neutral Pion Production from Deuterium at the Legs Facility

    NASA Astrophysics Data System (ADS)

    Hicks, K. H.; Ardashev, K.; Blecher, M.; Caracappa, A.; Cichocki, A.; Commeaux, C.; D'Angelo, A.; Didilez, J.-P.; Deininger, R.; Hoblit, S.; Khandaker, M.; Kistner, O.; Kuczewski, A.; Lincoln, F.; Lindgren, R.; Lehmann, A.; Lowry, M.; Lucas, M.; Meyer, H.; Miceli, L.; Opper, A.; Preedom, B. M.; Norum, B.; Sandorfi, A. M.; Schaerf, C.; Ströher, H.; Thorn, C. E.; Tonnison, J.; Wang, K.; Wei, X.; Whisnant, C. S.; Willits, D.

    2002-06-01

    Neutral pion photoproduction from a liquid deuterium target was measured in the energy region near 300 MeV at the LEGS facility of Brookhaven National Laboratory. The inclusive cross sections from deuterium are in agreement with measurments from Mainz, yet the exclusive cross sections and spin asymmetries for neutral pion production in coincidence with a detected nucleon are much smaller than expected from a quasi-free approximation. This may indicate that substantial final state interactions play a significant role, which will complicate the extraction of the desired amplitudes that would be measured if a free neutron target could be used.

  20. Calculation of Shock Hugoniot Curves of Precompressed Liquid Deuterium

    SciTech Connect

    Militzer, B

    2002-11-18

    Path integral Monte Carlo simulations have been used to study deuterium at high pressure and temperature. The equation of state has been derived in the temperature and density region of 10,000 {le} T {le} 1,000,000 and 0.6 {le} {rho} {le} 2.5 g cm{sup -3}. A series of shock Hugoniot curves is computed for different initial compressions in order to compare with current and future shock wave experiments using liquid deuterium samples precompressed in diamond anvil cells.

  1. Deuterium: Natural variations used as a biological tracer

    USGS Publications Warehouse

    Gleason, J.D.; Friedman, I.

    1970-01-01

    The suggestion is made that isotope tracing be carried out by monitoring the natural variations in deuterium concentrations. As an example, the natural variations in deuterium concentrations between food and water collected in Illinois and food and water collected in Colorado were used to determine the residence time of water in the blood and urine of rats. We observed not only a 51/2-day turnover time of water in the blood and urine, but also evidence for the influx of water vapor from the atmosphere through the lungs into the blood.

  2. Synthesis of deuterium labeled 17-methyl-testosterone

    SciTech Connect

    Shinohara, Y.; Baba, S.; Kasuya, Y.

    1984-09-01

    The synthesis of two forms of selectively deuterated 17-methyl-testosterone is described. 17-Methyl-d3-testosterone was prepared by the Grignard reaction of dehydroepiandrosterone with deuterium labeled methyl magnesium iodide followed by an Oppenauer oxidation. 17-Methyl-d3-testosterone-19,19,19-d3 was prepared by treating 3,3-ethylenedioxy-5,10-epoxy-5 alpha, 10 alpha-estran-17-one with deuterium labeled methyl magnesium bromide followed by hydrolysis and dehydration of the 5 alpha-hydroxyandrostane derivative.

  3. Deuterated C3H2 as a clue to deuterium chemistry

    NASA Technical Reports Server (NTRS)

    Gerin, M.; Combes, F.; Wootten, H. A.; Boulanger, F.; Peters, W. L., III; Kuiper, T. B. H.

    1987-01-01

    The deuterated cyclopropenylidene ring molecule, C3HD, has been detected toward several sources in four rotational lines, at 19, 79, 104, and 107 GHz. The relative integrated intensities of the 2-sub-12 - 1-sub-01 lines of C3HD and C3H2 are found in the ratio 1:5, indicating a high deuterium fractionation ratio for cyclopropenylidene. The detection of the C-13 isotope of C3H2 at the same position allows a determination of the optical thickness (about 3) of the line. The detection of such a large enhancement in the deuterated form of C3H2 very strongly suggests that a molecular ion is the chemical precursor of the molecules. Consideration of the amount of the enhancement relative to that in other molecules suggests that the precursor ion is C3H3+.

  4. Dissociation and ionization equilibria of deuterium fluid over a wide range of temperatures and densities

    SciTech Connect

    Zaghloul, Mofreh R.

    2015-06-15

    We investigate the dissociation and ionization equilibria of deuterium fluid over a wide range of temperatures and densities. The partition functions for molecular and atomic species are evaluated, in a statistical-mechanically consistent way, implementing recent developments in the literature and taking high-density effects into account. A new chemical model (free energy function) is introduced in which the fluid is considered as a mixture of diatomic molecules, atoms, ions, and free electrons. Intensive short range hard core repulsion is taken into account together with partial degeneracy of free electrons and Coulomb interactions among charged particles. Samples of computational results are presented as a set of isotherms for the degree of ionization, dissociated fraction of molecules, pressure, and specific internal energy for a wide range of densities and temperatures. Predictions from the present model calculations show an improved and sensible physical behavior compared to other results in the literature.

  5. The deuterium/hydrogen distribution in chondritic organic matter attests to early ionizing irradiation

    NASA Astrophysics Data System (ADS)

    Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Robert, François; Leroux, Hugues; Vezin, Hervé; Depecker, Christophe; Nuns, Nicolas; Lefebvre, Jean-Marc

    2015-10-01

    Primitive carbonaceous chondrites contain a large array of organic compounds dominated by insoluble organic matter (IOM). A striking feature of this IOM is the systematic enrichment in deuterium compared with the solar hydrogen reservoir. This enrichment has been taken as a sign of low-temperature ion-molecule or gas-grain reactions. However, the extent to which Solar System processes, especially ionizing radiation, can affect D/H ratios is largely unknown. Here, we report the effects of electron irradiation on the hydrogen isotopic composition of organic precursors containing different functional groups. From an initial terrestrial composition, overall D-enrichments and differential intramolecular fractionations comparable with those measured in the Orgueil meteorite were induced. Therefore, ionizing radiation can quantitatively explain the deuteration of organics in some carbonaceous chondrites. For these meteorites, the precursors of the IOM may have had the same isotopic composition as the main water reservoirs of the inner Solar System.

  6. The deuterium/hydrogen distribution in chondritic organic matter attests to early ionizing irradiation.

    PubMed

    Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Robert, François; Leroux, Hugues; Vezin, Hervé; Depecker, Christophe; Nuns, Nicolas; Lefebvre, Jean-Marc

    2015-01-01

    Primitive carbonaceous chondrites contain a large array of organic compounds dominated by insoluble organic matter (IOM). A striking feature of this IOM is the systematic enrichment in deuterium compared with the solar hydrogen reservoir. This enrichment has been taken as a sign of low-temperature ion-molecule or gas-grain reactions. However, the extent to which Solar System processes, especially ionizing radiation, can affect D/H ratios is largely unknown. Here, we report the effects of electron irradiation on the hydrogen isotopic composition of organic precursors containing different functional groups. From an initial terrestrial composition, overall D-enrichments and differential intramolecular fractionations comparable with those measured in the Orgueil meteorite were induced. Therefore, ionizing radiation can quantitatively explain the deuteration of organics in some carbonaceous chondrites. For these meteorites, the precursors of the IOM may have had the same isotopic composition as the main water reservoirs of the inner Solar System. PMID:26461170

  7. The deuterium/hydrogen distribution in chondritic organic matter attests to early ionizing irradiation

    PubMed Central

    Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Robert, François; Leroux, Hugues; Vezin, Hervé; Depecker, Christophe; Nuns, Nicolas; Lefebvre, Jean-Marc

    2015-01-01

    Primitive carbonaceous chondrites contain a large array of organic compounds dominated by insoluble organic matter (IOM). A striking feature of this IOM is the systematic enrichment in deuterium compared with the solar hydrogen reservoir. This enrichment has been taken as a sign of low-temperature ion-molecule or gas-grain reactions. However, the extent to which Solar System processes, especially ionizing radiation, can affect D/H ratios is largely unknown. Here, we report the effects of electron irradiation on the hydrogen isotopic composition of organic precursors containing different functional groups. From an initial terrestrial composition, overall D-enrichments and differential intramolecular fractionations comparable with those measured in the Orgueil meteorite were induced. Therefore, ionizing radiation can quantitatively explain the deuteration of organics in some carbonaceous chondrites. For these meteorites, the precursors of the IOM may have had the same isotopic composition as the main water reservoirs of the inner Solar System. PMID:26461170

  8. Influence of tungsten microstructure and ion flux on deuterium plasma-induced surface modifications and deuterium retention

    NASA Astrophysics Data System (ADS)

    Buzi, L.; De Temmerman, G.; Unterberg, B.; Reinhart, M.; Dittmar, T.; Matveev, D.; Linsmeier, Ch.; Breuer, U.; Kreter, A.; Van Oost, G.

    2015-08-01

    The influence of surface temperature, particle flux density and material microstructure on the surface morphology and deuterium retention was studied by exposing tungsten targets (20 μm and 40 μm grain size) to deuterium plasma at the same particle fluence (1026 m-2) and incident ion energy (40 eV) to two different ion fluxes (low flux: 1022 m-2 s-1, high flux: 1024 m-2 s-1). The maximum of deuterium retention was observed at ∼630 K for low flux density and at ∼870 K for high flux density, as indicated from the thermal desorption spectroscopy data (TDS). Scanning electron microscopy observations revealed the presence of blisters with a diameter of up to 1 μm which were formed at high flux density and high temperature (1170 K) contrasting with previously reported surface modification results at such exposure conditions.

  9. Specific features of X-ray generation by plasma focus chambers with deuterium and deuterium-tritium fillings

    NASA Astrophysics Data System (ADS)

    Dulatov, A. K.; Krapiva, P. S.; Lemeshko, B. D.; Mikhailov, Yu. V.; Moskalenko, I. N.; Prokuratov, I. A.; Selifanov, A. N.

    2016-01-01

    The process of hard X-ray (HXR) generation in plasma focus (PF) chambers was studied experimentally. The radiation was recorded using scintillation detectors with a high time resolution and thermoluminescent detectors in combination with the method of absorbing filters. Time-resolved analysis of the processes of neutron and X-ray generation in PFs is performed. The spectra of HXR emission from PF chambers with deuterium and deuterium-tritium fillings are determined. In experiments with PF chambers filled with a deuterium-tritium mixture, in addition to the HXR pulse with photon energies of up to 200-300 keV, a γ-ray pulse with photon energies of up to 2.5-3.0 MeV is recorded, and a mechanism of its generation is proposed.

  10. Roughening and reflection performance of molybdenum coatings exposed to a high-flux deuterium plasma

    NASA Astrophysics Data System (ADS)

    Eren, B.; Marot, L.; Ryzhkov, I. V.; Lindig, S.; Houben, A.; Wisse, M.; Skoryk, O. O.; Oberkofler, M.; Voitsenya, V. S.; Linsmeier, Ch.; Meyer, E.

    2013-11-01

    Optical diagnostic systems of ITER are foreseen to include metallic, plasma-facing, electromagnetic radiation reflecting components called first mirrors (FMs). Molybdenum coatings are important candidates for these components. Depending on the local plasma parameters of the reactor, the mirrors may be under net erosion or deposition conditions. In this work, we exposed molybdenum coatings to a high-flux deuterium plasma in order to test their roughening limits under erosion conditions. The high energy of deuterium ions (500 eV on average) results in more vigorous roughening of the surface compared with lower energy ions (200 eV). Longer exposure (3 × 1020 ions cm-2) of the 200 eV ions results in only a slightly increased roughness compared with shorter exposure (6.8 × 1019 ions cm-2). Both phenomena match to the theory regarding roughening dynamics of physical sputtering. A comparison of results in this work with previous studies gives support to the hypothesis that roughening is flux and temperature dependent. Partial delamination of the coatings is observed upon exposure at room temperature, but not at an elevated temperature (200 °C). In summary, Mo coatings will remain functional in the ITER environment under the expected conditions. However, changes in the expected conditions such as 500 eV mean energy of impinging charge exchange neutrals or <100 °C surface temperature of the mirrors can lead to gradual or sudden failure of the coatings.

  11. 10 CFR 110.24 - General license for the export of deuterium.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false General license for the export of deuterium. 110.24... MATERIAL Licenses § 110.24 General license for the export of deuterium. (a) A general license is issued to any person to export to any country not listed in § 110.28 or § 110.29 deuterium in...

  12. 10 CFR 110.24 - General license for the export of deuterium.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false General license for the export of deuterium. 110.24... MATERIAL Licenses § 110.24 General license for the export of deuterium. (a) A general license is issued to any person to export to any country not listed in § 110.28 or § 110.29 deuterium in...

  13. 10 CFR 110.24 - General license for the export of deuterium.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false General license for the export of deuterium. 110.24... MATERIAL Licenses § 110.24 General license for the export of deuterium. (a) A general license is issued to any person to export deuterium in individual shipments of 10 kilograms or less (50 kilograms of...

  14. 10 CFR 110.24 - General license for the export of deuterium.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false General license for the export of deuterium. 110.24... MATERIAL Licenses § 110.24 General license for the export of deuterium. (a) A general license is issued to any person to export to any country not listed in § 110.28 or § 110.29 deuterium in...

  15. 10 CFR 110.24 - General license for the export of deuterium.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false General license for the export of deuterium. 110.24... MATERIAL Licenses § 110.24 General license for the export of deuterium. (a) A general license is issued to any person to export to any country not listed in § 110.28 or § 110.29 deuterium in...

  16. Carbon Nanotube Based Deuterium Ion Source for Improved Neutron Generators

    SciTech Connect

    Fink, R. L.; Jiang, N.; Thuesen, L.; Leung, K. N.; Antolak, A. J.

    2009-03-10

    Field ionization uses high electric fields to cause the ionization and emission of ions from the surface of a sharp electrode. We are developing a novel field ionization neutron generator using carbon nanotubes (CNT) to produce the deuterium ion current. The generator consists of three major components: a deuterium ion source made of carbon nanotubes, a smooth negatively-biased target electrode, and a secondary electron suppression system. When a negative high voltage is applied on the target electrode, a high gradient electric field is formed at the tips of the carbon nanotubes. This field is sufficiently strong to create deuterium (D) ions at or near the nanotubes which are accelerated to the target causing D-D reactions to occur and the production of neutrons. A cross magnetic field is used to suppress secondary emission electrons generated on the target surface. We have demonstrated field ionization currents of 70 nA (1 {mu}A/cm{sup 2}) at hydrogen gas pressure of 10 mTorr. We have found that the current scales proportionally with CNT area and also with the gas pressure in the range of 1 mTorr to 10 mTorr. We have demonstrated pulse cut-off times as short as 2 {mu}sec. Finally, we have shown the feasibility of generating neutrons using deuterium gas.

  17. URBAN STORMWATER TRACING WITH THE NATURALLY OCCURRING DEUTERIUM ISOTOPE

    EPA Science Inventory

    Measurements of the naturally-occurring deuterium isotope assist the tracing of water components during wet-weather flows in an urban watershed. A transect of installations in the vadose and saturated zones was completed in the vicinity of a small stream and storm sewer. High-r...

  18. Ordered ground states of metallic hydrogen and deuterium

    NASA Technical Reports Server (NTRS)

    Ashcroft, N. W.

    1981-01-01

    The physical attributes of some of the more physically distinct ordered states of metallic hydrogen and metallic deuterium at T = 0 and nearby are discussed. The likelihood of superconductivity in both is considered with respect to the usual coupling via the density fluctuations of the ions.

  19. Deuterium in interstitial water from deep-sea cores

    USGS Publications Warehouse

    Friedman, I.; Hardcastle, K.

    1988-01-01

    As part of the Joint Oceanographic Institutions Deep Earth Sampling project, the interstitial waters of cores from 69 holes were sampled for deuterium analysis to examine changes in the deuterium content of the oceans with time. Changes in the abundance of deuterium can be related to changes in the amount of ice stored in continental glaciers, inasmuch as precipitation in the form of snow is highly depleted in deuterium compared with the oceans. Many of the cores show a change in isotopic composition of samples from early to late Miocene that can be ascribed to the buildup of the Antarctic ice sheets. After correcting for the role of diffusion in reducing the isotopic contrast between samples from a single core, we estimate an incrase of 10 per mil (???) ??D (corresponding to a ??18O change of about 1.2???) between the early and late Miocene. A similar analysis of Pleistocene to Holocene changes indicates a ??D rise of 8??? during the time of maximum continental ice, which corresponds to a ??18O increase of about 1.0???. On the basis of limited data, we find no ??D change in the oceans from Cretaceous to Miocene. -from Authors

  20. 78 FR 79021 - Request for a License To Export; Deuterium

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-27

    ... COMMISSION Request for a License To Export; Deuterium Pursuant to 10 CFR 110.70 (b) ``Public Notice of....gov/reading-rm.html at the NRC Homepage. A request for a hearing or petition for leave to intervene... Secretary, U.S. Department of State, Washington, DC 20520. A request for a hearing or petition for leave...

  1. 78 FR 79018 - Request for a License To Export Deuterium

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-27

    ... August 2007, 72 FR 49139 (Aug. 28, 2007). Information about filing electronically is available on the NRC... COMMISSION Request for a License To Export Deuterium Pursuant to 10 CFR 110.70 (b) ``Public Notice of Receipt....gov/reading-rm.html at the NRC Homepage. A request for a hearing or petition for leave to...

  2. Heterogeneous Catalysis: Deuterium Exchange Reactions of Hydrogen and Methane

    ERIC Educational Resources Information Center

    Mirich, Anne; Miller, Trisha Hoette; Klotz, Elsbeth; Mattson, Bruce

    2015-01-01

    Two gas phase deuterium/hydrogen exchange reactions are described utilizing a simple inexpensive glass catalyst tube containing 0.5% Pd on alumina through which gas mixtures can be passed and products collected for analysis. The first of these exchange reactions involves H[subscript 2] + D[subscript 2], which proceeds at temperatures as low as 77…

  3. Ground-state energetics of helium and deuterium fermion fluids

    NASA Astrophysics Data System (ADS)

    Krotscheck, E.; Smith, R. A.; Clark, J. W.; Panoff, R. M.

    1981-12-01

    The method of correlated basis functions (CBF) is applied to the evaluation of the ground-state energy of atomic fermion fluids as a function of density. As a first step, liquid 3He in both unpolarized and fully polarized spin configurations is considered variationally, using Slater-Jastrow trial wave functions. Results are reported for a conventional analytic choice of the state-independent two-body correlation function f(r) and for the optimal f(r) determined by the solution of a suitable Euler equation. The Jastrow treatment is found to be inadequate in that (i) the energy expectation value lies above the experimental equilibrium energy by some 1.5 K, and (ii) the polarized phase is predicted to be more stable than the unpolarized one. For a given polarization, a correlated basis is formed by application of the assumed Jastrow correlation factor to the elements of a complete set of noninteracting-Fermi-gas Slater determinants. The exact ground-state energy may be developed in a perturbation expansion in the correlated basis, the leading term being the Jastrow energy expectation value. Considerable improvement on the Jastrow description of the unpolarized phase is achieved upon inclusion of the correlated two-particle-two-hole component of the second-order CBF perturbation correction. At the experimental equilibrium density, this contribution, which incorporates important momentum- and spin-dependent correlations, can amount to some 0.6-1.1 K [depending on the choice of f(r)]. The required correlated-basis matrix elements are calculated by Fermi hypernetted-chain (FHNC) techniques, crucial Pauli effects of the elementary diagrams being introduced through the FHNC/C algorithm. The Euler equation is approximated within the same framework. The momentum-space integrations in the second-order perturbation correction are evaluated by a Monte Carlo procedure. One may reasonably expect that further refinements of the CBF method will lead to an accurate microscopic

  4. High electric field deuterium ion sources for neutron generators

    NASA Astrophysics Data System (ADS)

    Reichenbach, Birk

    Active interrogation systems for highly enriched uranium require improved fieldable neutron sources. The target technology for deuterium-tritium neutron generators is well understood and the most significant improvement can be achieved by improving the deuterium ion source through increased output and, in some cases, lifetime of the ion source. We are developing a new approach to a deuterium ion sources based upon the field desorption/evaporation of deuterium from the surfaces of metal tips. Electrostatic field desorption (EFD) desorbs previously adsorbed deuterium as ions under the influence of high electric fields (several V/A), without removing tip material. Single etched wire tip experiments have been performed and have shown that this is difficult but can be achieved with molybdenum and tungsten tips. Electrostatic field evaporation (EFE) evaporates ultra thin deuterated titanium films as ions. It has been shown that several 10s of atomic layers can be removed within a few nanoseconds from etched tungsten tips. In the course of these studies titanium deposition and deuteration methods were studied and new detection methods developed. Space charge effects resulting from the large ion currents were identified to be the most likely cause of some unusual ion emission characteristics. In addition, on W < 110 > oriented substrates a surprising body-centered cubic crystal structure of the titanium film was found and studied. The ion currents required for neutron generator applications can be achieved by microfabrication of metal tip arrays. Field desorption studies of microfabricated field emitter tip arrays have been conducted for the first time. Maximum fields of 3 V/A have been applied to the array tip surfaces to date, although fields of ˜ 2 V/A to ˜ 2.5 V/A are more typical. Desorption of atomic deuterium ions has been observed at fields of roughly 2 V/A at room temperature. The desorption of common surface adsorbates, such as hydrogen, carbon, water, and

  5. The Influence of Salinity, Growth Rate and Temperature on D/H Fractionation in Algal Lipids from Culture and Field Studies

    NASA Astrophysics Data System (ADS)

    Sachs, J. P.; Schwab, V.; Sachse, D.; Cash, A.; Nelson, D.; Zhang, Z.; Kawka, O.

    2007-12-01

    The use of compound-specific D/H ratios to decipher biochemical, geochemical, oceanographic, and climatic processes is expanding rapidly. The relative success of these efforts depends on an understanding of the environmental conditions that influence the deuterium depletion relative to environmental water observed in all plant, algal and bacterial lipids, and the sensitivity of D/H fractionation responses to changes in those environmental conditions. Presently very little is known about this interplay between the environment and D/H fraction in algal lipids. Here we present results from field studies (in the Chesapeake Bay, Christmas Island, the Great Salt Lake, and saline basins in Alberta and Saskatchewan) and culture studies (both continuous and batch) that indicate that salinity, growth rate and temperature each influence D/H fractionation in algal lipids to varying degrees, depending on the algae and the lipid. Our initial results indicate that D/H fractionation (1) decreases with increasing salinity, (2) increases with increasing growth rate in isoprenoid lipids, (3) is insensitive to growth rate in acetogenic lipids, and (4) increases with increasing temperature.

  6. Development of Approaches for Deuterium Incorporation in Plants

    SciTech Connect

    Evans, Barbara R

    2015-01-01

    Soon after the discovery of deuterium, efforts to utilize this stable isotope of hydrogen for labeling of plants began and have proven successful for natural abundance to 20% enrichment. However, isotopic labeling with deuterium (2H) in higher plants at the level of 40% and higher is complicated by both physiological responses, particularly water exchange through transpiration, and inhibitory effects of D2O on germination, rooting, and growth. The highest incorporation of 40 50% had been reported for photoheterotrophic cultivation of the duckweed Lemna. Higher substitution is desirable for certain applications using neutron scattering and nuclear magnetic resonance (NMR) techniques. 1H2H-NMR and mass spectroscopy are standard methods frequently used for determination of location and amount of deuterium substitution. The changes in infrared (IR) absorption observed for H to D substitution in hydroxyl and alkyl groups provide rapid initial evaluation of incorporation. Short-term experiments with cold-tolerant annual grasses can be carried out in enclosed growth containers to evaluate incorporation. Growth in individual chambers under continuous air perfusion with dried sterile-filtered air enables long-term cultivation of multiple plants at different D2O concentrations. Vegetative propagation from cuttings extends capabilities to species with low germination rates. Cultivation in 50% D2O of annual ryegrass and switchgrass following establishment of roots by growth in H2O produces samples with normal morphology and 30 40 % deuterium incorporation in the biomass. Winter grain rye (Secale cereale) was found to efficiently incorporate deuterium by photosynthetic fixation from 50% D2O but did not incorporate deuterated phenylalanine-d8 from the growth medium.

  7. Development of approaches for deuterium incorporation in plants.

    PubMed

    Evans, Barbara R; Shah, Riddhi

    2015-01-01

    Soon after the discovery of deuterium, efforts to utilize this stable isotope of hydrogen for labeling of plants began and have proven successful for natural abundance to 20% enrichment. However, isotopic labeling with deuterium ((2)H) in higher plants at the level of 40% and higher is complicated by both physiological responses, particularly water exchange through transpiration, and inhibitory effects of D2O on germination, rooting, and growth. The highest incorporation of 40-50% had been reported for photoheterotrophic cultivation of the duckweed Lemna. Higher substitution is desirable for certain applications using neutron scattering and nuclear magnetic resonance (NMR) techniques. (1)H(2)H NMR and mass spectroscopy are standard methods frequently used for determination of location and amount of deuterium substitution. The changes in infrared (IR) absorption observed for H to D substitution in hydroxyl and alkyl groups provide rapid initial evaluation of incorporation. Short-term experiments with cold-tolerant annual grasses can be carried out in enclosed growth containers to evaluate incorporation. Growth in individual chambers under continuous air perfusion with dried sterile-filtered air enables long-term cultivation of multiple plants at different D2O concentrations. Vegetative propagation from cuttings extends capabilities to species with low germination rates. Cultivation in 50% D2O of annual ryegrass and switchgrass following establishment of roots by growth in H2O produces samples with normal morphology and 30-40% deuterium incorporation in the biomass. Winter grain rye (Secale cereale) was found to efficiently incorporate deuterium by photosynthetic fixation from 50% D2O but did not incorporate deuterated phenylalanine-d8 from the growth medium. PMID:26577734

  8. Deuterium enrichment by selective photo-induced dissociation of an organic carbonyl compound

    DOEpatents

    Marling, John B.

    1981-01-01

    A method for producing a deuterium enriched material by photoinduced dissociation which uses as the working material a gas phase photolytically dissociable organic carbonyl compound containing at least one hydrogen atom bonded to an atom which is adjacent to a carbonyl group and consisting of molecules wherein said hydrogen atom is present as deuterium and molecules wherein said hydrogen atom is present as another isotope of hydrogen. The organic carbonyl compound is subjected to intense infrared radiation at a preselected wavelength to selectively excite and thereby induce dissociation of the deuterium containing species to yield a deuterium enriched stable molecular product. Undissociated carbonyl compound, depleted in deuterium, is preferably redeuterated for reuse.

  9. First-principles opacity table of warm dense deuterium for inertial-confinement-fusion applications.

    PubMed

    Hu, S X; Collins, L A; Goncharov, V N; Boehly, T R; Epstein, R; McCrory, R L; Skupsky, S

    2014-09-01

    Accurate knowledge of the optical properties of a warm dense deuterium-tritium (DT) mixture is important for reliable design of inertial confinement fusion (ICF) implosions using radiation-hydrodynamics simulations. The opacity of a warm dense DT shell essentially determines how much radiation from hot coronal plasmas can be deposited in the DT fuel of an imploding capsule. Even for the simplest species of hydrogen, the accurate calculation of their opacities remains a challenge in the warm-dense matter regime because strong-coupling and quantum effects play an important role in such plasmas. With quantum-molecular-dynamics (QMD) simulations, we have derived a first-principles opacity table (FPOT) of deuterium (and the DT mixture by mass scaling) for a wide range of densities from ρ(D)=0.5 to 673.518g/cm(3) and temperatures from T=5000K up to the Fermi temperature T(F) for each density. Compared with results from the astrophysics opacity table (AOT) currently used in our hydrocodes, the FPOT of deuterium from our QMD calculations has shown a significant increase in opacity for strongly coupled and degenerate plasma conditions by a factor of 3-100 in the ICF-relevant photon-energy range. As conditions approach those of classical plasma, the opacity from the FPOT converges to the corresponding values of the AOT. By implementing the FPOT of deuterium and the DT mixture into our hydrocodes, we have performed radiation-hydrodynamics simulations for low-adiabat cryogenic DT implosions on the OMEGA laser and for direct-drive-ignition designs for the National Ignition Facility. The simulation results using the FPOT show that the target performance (in terms of neutron yield and energy gain) could vary from ∼10% up to a factor of ∼2 depending on the adiabat of the imploding DT capsule; the lower the adiabat, the more variation is seen in the prediction of target performance when compared to the AOT modeling. PMID:25314551

  10. Seeking the Limits of Low-Temperature Nuclear Fusion: Sticking in Muon-Catalyzed Fusion, and Piezonuclear Fusion in Deuterium/condensed Matter Systems

    NASA Astrophysics Data System (ADS)

    Taylor, Stuart F.

    Studies seeking an upper limit of two types of low temperature nuclear fusion is presented. The upper limit for muon catalyzed fusion is generally considered to be the number of fusions per muon obtainable. The limiting factor has been found to be how often the muon remains bound to the alpha produced by the fusion, known as the "sticking fraction." Experiments directly measuring the sticking and determining the sticking using high tritium fractions are presented. In deuterium/condensed matter systems the question is nearly whether nuclear fusion proceeds at all. Experiments where neutrons around deuterided titanium and palladium are measured are presented.

  11. Dietary peptides from the non-digestible fraction of Phaseolus vulgaris L. decrease angiotensin II-dependent proliferation in HCT116 human colorectal cancer cells through the blockade of the renin-angiotensin system.

    PubMed

    Luna-Vital, Diego A; Liang, Katie; González de Mejía, Elvira; Loarca-Piña, Guadalupe

    2016-05-18

    This study aimed to determine the ability of peptides present in the non-digestible fraction (NDF) of common beans to decrease angiotensin II (AngII) through the blockade of RAS and its effect on the proliferation of HCT116 human colorectal cancer cells. Pure synthesized peptides GLTSK and GEGSGA and the peptide fractions (PF) of cultivars Azufrado Higuera and Bayo Madero were used. The cells were pretreated with pure peptides, PF or AGT at their IC50 or IC25 values, in comparison with the simultaneous treatment of peptides and AGT. For western blot and microscopy analysis, 100 μM and 0.5 mg mL(-1) were used for pure peptides and PF treatments, respectively. According to the ELISA tests, GLTSK and GEGSGA decreased (p < 0.05) the conversion rate of AGT to angiotensin I (AngI) by 38 and 28%, respectively. All the peptides tested reduced (p < 0.05) the conversion rate of AngI to AngII from 38 to 50%. When the cells were pretreated with both pure peptides and PF before exposure to AGT, the effectiveness inhibiting cell proliferation was higher than the simultaneous treatment suggesting their preventive effects. GLTSK and GEGSGA interacted with the catalytic site of renin, the angiotensin-I converting enzyme, and the AngII receptor, mainly through hydrogen bonds, polar, hydrophobic and cation-π interactions according to molecular docking. Through confocal microscopy, it was determined that GLTSK and GEGSGA caused the decrease (p < 0.05) of AngII-dependent STAT3 nuclear activation in HCT116 cells by 66 and 23%, respectively. The results suggest that peptides present in the common bean NDF could potentially ameliorate the effects of RAS overexpression in colorectal cancer. PMID:27156533

  12. Preliminary study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAΦNE

    NASA Astrophysics Data System (ADS)

    Bazzi, M.; Beer, G.; Berucci, C.; Bombelli, L.; Bragadireanu, A. M.; Cargnelli, M.; Curceanu (Petrascu), C.; d'Uffizi, A.; Fiorini, C.; Frizzi, T.; Ghio, F.; Guaraldo, C.; Hayano, R.; Iliescu, M.; Ishiwatari, T.; Iwasaki, M.; Kienle, P.; Levi Sandri, P.; Longoni, A.; Marton, J.; Okada, S.; Pietreanu, D.; Ponta, T.; Romero Vidal, A.; Sbardella, E.; Scordo, A.; Shi, H.; Sirghi, D. L.; Sirghi, F.; Tatsuno, H.; Tudorache, A.; Tudorache, V.; Vazquez Doce, O.; Widmann, E.; Zmeskal, J.

    2013-06-01

    The study of the K¯N system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. At the DAΦNE electron-positron collider of Laboratori Nazionali di Frascati we studied kaonic atoms with Z=1 and Z=2, taking advantage of the low-energy charged kaons from Φ-mesons decaying nearly at rest. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width of the lowest experimentally accessible level (1s for H and D and 2p for He). Shift and width are connected to the real and imaginary part of the scattering length. To disentangle the isospin dependent scattering lengths of the antikaon-nucleon interaction, measurements of K-p and of K-d are needed. We report here on an exploratory deuterium measurement, from which a limit for the yield of the K-series transitions was derived: Y(Ktot)<0.0143 and Y(Kα)<0.0039 (CL 90%). Also, the upcoming SIDDHARTA-2 kaonic deuterium experiment is introduced.

  13. Effect of pulse duration on resonant heating of laser-irradiated argon and deuterium clusters.

    PubMed

    Gupta, Ayush; Antonsen, T M; Taguchi, T; Palastro, J

    2006-10-01

    We study the effect of pulse duration on the heating of single van der Waals bound argon and deuterium clusters by a strong laser field using a two-dimensional (2D) electrostatic particle-in-cell (PIC) code in the range of laser-cluster parameters such that kinetic as well as hydrodynamic effects are active. Heating is dominated by a collisionless resonant absorption process that involves energetic electrons transiting through the cluster. A size-dependent intensity threshold defines the onset of this resonance [T. Taguchi, Physical Review Letters, 92, 20 (2004)]. It is seen that increasing the laser pulse duration lowers this intensity threshold and the energetic electrons take multiple laser periods to transit the cluster instead of one laser period. Our simulations also show that strong electron heating is accompanied by the generation of a high-energy peak in the ion energy distribution function. We also calculate the yield of thermonuclear fusion neutrons from exploding deuterium clusters using the PIC model with periodic boundary conditions that allows for the interaction of ions from neighboring clusters. PMID:17155183

  14. New reaction rates for improved primordial D /H calculation and the cosmic evolution of deuterium

    NASA Astrophysics Data System (ADS)

    Coc, Alain; Petitjean, Patrick; Uzan, Jean-Philippe; Vangioni, Elisabeth; Descouvemont, Pierre; Iliadis, Christian; Longland, Richard

    2015-12-01

    Primordial or big bang nucleosynthesis (BBN) is one of the three historically strong evidences for the big bang model. Standard BBN is now a parameter-free theory, since the baryonic density of the Universe has been deduced with an unprecedented precision from observations of the anisotropies of the cosmic microwave background radiation. There is a good agreement between the primordial abundances of 4He, D, 3He, and 7Li deduced from observations and from primordial nucleosynthesis calculations. However, the 7Li calculated abundance is significantly higher than the one deduced from spectroscopic observations and remains an open problem. In addition, recent deuterium observations have drastically reduced the uncertainty on D /H , to reach a value of 1.6%. It needs to be matched by BBN predictions whose precision is now limited by thermonuclear reaction rate uncertainties. This is especially important as many attempts to reconcile Li observations with models lead to an increased D prediction. Here, we reevaluate the d (p ,γ )3He, d (d ,n ) 3H3, and d (d ,p ) 3H reaction rates that govern deuterium destruction, incorporating new experimental data and carefully accounting for systematic uncertainties. Contrary to previous evaluations, we use theoretical ab initio models for the energy dependence of the S factors. As a result, these rates increase at BBN temperatures, leading to a reduced value of D /H =(2.45 ±0.10 )×10-5 (2 σ ), in agreement with observations.

  15. Preliminary study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAΦNE

    PubMed Central

    Bazzi, M.; Beer, G.; Berucci, C.; Bombelli, L.; Bragadireanu, A.M.; Cargnelli, M.; Curceanu (Petrascu), C.; dʼUffizi, A.; Fiorini, C.; Frizzi, T.; Ghio, F.; Guaraldo, C.; Hayano, R.; Iliescu, M.; Ishiwatari, T.; Iwasaki, M.; Kienle, P.; Levi Sandri, P.; Longoni, A.; Marton, J.; Okada, S.; Pietreanu, D.; Ponta, T.; Romero Vidal, A.; Sbardella, E.; Scordo, A.; Shi, H.; Sirghi, D.L.; Sirghi, F.; Tatsuno, H.; Tudorache, A.; Tudorache, V.; Vazquez Doce, O.; Widmann, E.; Zmeskal, J.

    2013-01-01

    The study of the K¯N system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. At the DAΦNE electron–positron collider of Laboratori Nazionali di Frascati we studied kaonic atoms with Z=1 and Z=2, taking advantage of the low-energy charged kaons from Φ-mesons decaying nearly at rest. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width of the lowest experimentally accessible level (1s for H and D and 2p for He). Shift and width are connected to the real and imaginary part of the scattering length. To disentangle the isospin dependent scattering lengths of the antikaon–nucleon interaction, measurements of K−p and of K−d are needed. We report here on an exploratory deuterium measurement, from which a limit for the yield of the K-series transitions was derived: Y(Ktot)<0.0143 and Y(Kα)<0.0039 (CL 90%). Also, the upcoming SIDDHARTA-2 kaonic deuterium experiment is introduced. PMID:23805024

  16. Coupled interactions between tungsten surfaces and transient high-heat-flux deuterium plasmas

    NASA Astrophysics Data System (ADS)

    Takamura, S.; Uesugi, Y.

    2015-03-01

    Fundamental studies on the interactions between transient deuterium-plasma heat pulses and tungsten surfaces were carried out in terms of electrical, mechanical and thermal response in a compact plasma device AIT-PID (Aichi Institute of Technology-Plasma Irradiation Device). Firstly, electron-emission-induced surface-temperature increase is discussed in the surface-temperature range near tungsten's melting point, which is accomplished by controlling the sheath voltage and power transmission factor. Secondly, anomalous penetration of tungsten atomic efflux into the surrounding plasma was observed in addition to a normal layered population; it is discussed in terms of the effect of substantial tungsten influx into the deuterium plasma, which causes dissipation of plasma electron energy. Thirdly, a momentum input from pulsed plasma onto a tungsten target was observed visually. The force is estimated numerically by the accelerated ion flow to the target as well as the reaction of tungsten-vapour efflux. Finally, a discussion follows on the effects of the plasma heat pulses on the morphology of tungsten surface (originally a helium-induced ‘fuzzy’ nanostructure). A kind of bifurcated effect is obtained: melting and annealing. Open questions remain for all the phenomena observed, although sheath-voltage-dependent plasma-heat input may be a key parameter. Discussions on all these phenomena are provided by considering their implications to tokamak fusion devices.

  17. HYDROGEN AND DEUTERIUM NMR OF SOLIDS BY MAGIC ANGLE SPINNING

    SciTech Connect

    Eckman, R.R.

    1982-10-01

    The nuclear magnetic resonance of solids has long been characterized by very large spectral broadening which arises from internuclear dipole-dipole coupling or the nuclear electric quadrupole interaction. These couplings can obscure the smaller chemical shift interaction and make that information unavailable. Two important and difficult cases are that of hydrogen and deuterium. For example, the homonuclear dipolar broadening, HD, for hydrogen is usually several tens of kilohertz. For deuterium, HD is relatively small; however, the quadrupole interaction causes a broadening which can be hundreds of kilohertz in polycrystalline or amorphous solids. The development of cross polarization, heteronuclear radiofrequency decoupling, and coherent averaging of nuclear spin interactions has provided measurement of chemical shift tensors in solids. Recently, double quantum NMR and double quantum decoupling have led to measurement of deuterium and proton chemical shift tensors, respectively. A general problem of these experiments is the overlapping of the tensor powder pattern spectra of magnetically distinct sites which cannot be resolved. In this work, high resolution NMR of hydrogen and deuterium in solids is demonstrated. For both nuclei, the resonances are narrowed to obtain liquid-like isotropic spectra by high frequency rotation of the sample about an axis inclined at the magic angle, {beta}{sub m} = Arccos(3{sup -1/2}), with respect to the direction of the external magnetic field. Two approaches have been developed for each nucleus. For deuterium, the powder spectra were narrowed by over three orders of magnitude by magic angle rotation with precise control of {beta}. A second approach was the observation of deuterium double quantum transitions under magic angle rotation. For hydrogen, magic angle rotation alone could be applied to obtain the isotropic spectrum when H{sub D} was small. This often occurs naturally when the nuclei are semi-dilute or involved in internal

  18. Suppression of blister formation and deuterium retention on tungsten surface due to mechanical polishing and helium pre-exposure

    NASA Astrophysics Data System (ADS)

    Nishijima, D.; Iwakiri, H.; Amano, K.; Ye, M. Y.; Ohno, N.; Tokunaga, K.; Yoshida, N.; Takamura, S.

    2005-07-01

    Low-energy deuterium (D) plasma exposure on tungsten (W), which is an important material for ITER, results in blister formation on the surface. Blister formation increases both micron-sized dust production and D retention. Blister formation depends greatly on surface pre-treatment. Deuterium plasma exposure on mirror-finished powder metallurgy W at 500 K for 3 h forms a blister with a diameter of a few hundred micrometres on the surface. Blister formations on the mechanically-polished and helium-pre-exposed surfaces are drastically suppressed. Deuterium retention is also reduced on both the mechanically-polished surface and the helium-pre-exposed surface compared with that on the mirror-finished surface. The suppressive effect of blister formation on the mechanically-polished surface is maintained for 50 h. The size of blisters and D retention on mirror-finished surface exposed for 50 h increases by some degrees (<~500 µm, 7 × 1020 m-2) compared with that on mirror-finished surface exposed for 3 h (<~200 µm, 5 × 1020 m-2), but is not proportional to the exposure time. The saturation level of D retention even on blister-rich surfaces seems to be lower than an order of 1021 D2 m-2.

  19. Effects of Low-Level Deuterium Enrichment on Bacterial Growth

    PubMed Central

    Xie, Xueshu; Zubarev, Roman A.

    2014-01-01

    Using very precise (±0.05%) measurements of the growth parameters for bacteria E. coli grown on minimal media, we aimed to determine the lowest deuterium concentration at which the adverse effects that are prominent at higher enrichments start to become noticeable. Such a threshold was found at 0.5% D, a surprisingly high value, while the ultralow deuterium concentrations (≤0.25% D) showed signs of the opposite trend. Bacterial adaptation for 400 generations in isotopically different environment confirmed preference for ultralow (≤0.25% D) enrichment. This effect appears to be similar to those described in sporadic but multiple earlier reports. Possible explanations include hormesis and isotopic resonance phenomena, with the latter explanation being favored. PMID:25033078

  20. Techniques for determining total body water using deuterium oxide

    NASA Technical Reports Server (NTRS)

    Bishop, Phillip A.

    1990-01-01

    The measurement of total body water (TBW) is fundamental to the study of body fluid changes consequent to microgravity exposure or treatment with microgravity countermeasures. Often, the use of radioactive isotopes is prohibited for safety or other reasons. It was selected and implemented for use by some Johnson Space Center (JCS) laboratories, which permitted serial measurements over a 14 day period which was accurate enough to serve as a criterion method for validating new techniques. These requirements resulted in the selection of deuterium oxide dilution as the method of choice for TBW measurement. The development of this technique at JSC is reviewed. The recommended dosage, body fluid sampling techniques, and deuterium assay options are described.

  1. Inelastic x-ray scattering from shocked liquid deuterium.

    PubMed

    Regan, S P; Falk, K; Gregori, G; Radha, P B; Hu, S X; Boehly, T R; Crowley, B J B; Glenzer, S H; Landen, O L; Gericke, D O; Döppner, T; Meyerhofer, D D; Murphy, C D; Sangster, T C; Vorberger, J

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation-driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Ly(α) line emission at 2.96 keV. These first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5  eV, an electron density of 2.2(±0.5)×10(23)  cm(-3), and an ionization of 0.8 (-0.25, +0.15). Two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results. PMID:23368573

  2. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    SciTech Connect

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B.; Glenzer, S. H.; Landen, O.; Gericke, D. O.; Doeppner, T.; Meyerhofer, D. D.; Murphy, C. D.; Sangster, T. C.; Vorberger, J.

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  3. Production of ultradense deuterium: A compact future fusion fuel

    SciTech Connect

    Badiei, Shahriar; Andersson, Patrik U.; Holmlid, Leif

    2010-03-22

    Ultradense deuterium as a nuclear fuel in laser-ignited inertial confinement fusion appears to have many advantages. The density of ultradense deuterium D(-1) is as high as 140 kg cm{sup -3} or 10{sup 29} cm{sup -3}. This means that D(-1) will be very useful as a target fuel, circumventing the complex and unstable laser compression stage. We show that the material is stable apart from the oscillation between two forms, and can exist for days in the laboratory environment. We also demonstrate that an amount of D(-1) corresponding to tens of kilojoules is produced in each experiment. This may be sufficient for break-even.

  4. Antiproton annihilation at rest in nitrogen and deuterium gas

    SciTech Connect

    Riedlberger, J.; Amsler, C.; Doser, M.; Straumann, U.; Truol, P. ); Bailey, D.; Barlag, S.; Gastaldi, U.; Landua, R.; Sabev, C. ); Duch, K.D.; Heel, M.; Kalinowsky, H.; Kayser, F.; Klempt, E.; May, B.; Schreiber, O.; Weidenauer, P.; Ziegler, M. ); Dahme, W.; Feld-Dahme, F.; Schaefer, U.

    1989-12-01

    Results on antiproton absorption at rest in gaseous nitrogen and deuterium are presented from an analysis of approximately 10{sup 6} events each taken with a magnetic spectrometer. Inclusive features such as pion and proton multiplicities and spectra are presented. Data relating to absorption modes requiring more than one nucleon, such as the {Lambda} yield, the {Lambda} spectrum, and the exclusive deuterium channels {ital {bar p}d}{r arrow}{pi}{sup {minus}}p, {Lambda}{ital K}{sup +}{pi}{sup {minus}} are discussed. The fully reconstructable channels {ital {bar p}}d{r arrow}{pi}{sup +}{pi}{sup {minus}}{pi}{sup {minus}}{ital p},{pi}{sup +}{pi}{sup +} {pi}{sup {minus}}{pi}{sup {minus}}{pi}{sup {minus}}{ital p} also show a high-energy proton tail unaccounted for by single nucleon rescattering mechanisms.

  5. Results from deuterium-tritium tokamak confinement experiments

    SciTech Connect

    Hawryluk, R.J.

    1997-02-01

    Recent scientific and technical progress in magnetic fusion experiments has resulted in the achievement of plasma parameters (density and temperature) which enabled the production of significant bursts of fusion power from deuterium-tritium fuels and the first studies of the physics of burning plasmas. The key scientific issues in the reacting plasma core are plasma confinement, magnetohydrodynamic (MHD) stability, and the confinement and loss of energetic fusion products from the reacting fuel ions. Progress in the development of regimes of operation which have both good confinement and are MHD stable have enabled a broad study of burning plasma physics issues. A review of the technical and scientific results from the deuterium-tritium experiments on the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) is given with particular emphasis on alpha-particle physics issues.

  6. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    DOE PAGESBeta

    Regan, S. P.; Falk, K.; Gregori, G.; Radha, P. B.; Hu, S. X.; Boehly, T. R.; Crowley, B.; Glenzer, S. H.; Landen, O.; Gericke, D. O.; et al

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Lyα line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×1023 cm-3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

  7. Near-threshold photoproduction of ϕ mesons from deuterium

    NASA Astrophysics Data System (ADS)

    Clas Collaboration; Qian, X.; Chen, W.; Gao, H.; Hicks, K.; Kramer, K.; Laget, J. M.; Mibe, T.; Qiang, Y.; Stepanyan, S.; Tedeschi, D. J.; Xu, W.; Adhikari, K. P.; Amaryan, M.; Anghinolfi, M.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bellis, M.; Biselli, A. S.; Bookwalter, C.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Cole, P. L.; Collins, P.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Deur, A.; Dey, B.; Dhamija, S.; Djalali, C.; Doughty, D.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Eugenio, P.; Fegan, S.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Jawalkar, S. S.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Konczykowski, P.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Martinez, D.; Mayer, M.; McAndrew, J.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mikhailov, K.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, I.; Niroula, M. R.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Park, S.; Pereira, S. Anefalos; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, C. E.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vineyard, M. F.; Voutier, E.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

    2011-02-01

    We report the first, kinematically-complete measurement of the differential cross section of ϕ-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, K+ and K- near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections dσdt for the initial photon energy range of 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Our finding is different from recent LEPS results on ϕ-meson photoproduction from deuterium in a similar incident photon energy range, but in a different momentum transfer region.

  8. Neutron production in deuterium gas-puff implosions on the refurbished Z accelerator.

    SciTech Connect

    Flicker, Dawn G.; Coverdale, Christine Anne; Velikovich, Aleksandr Lazarevich; Clark, R. W.; Chong, Y. K.; Davis, J.; Giuliani, J. L.

    2010-06-01

    It has been experimentally demonstrated that deuterium gas-puff implosions at >15 MA are powerful sources of fusion neutrons. Analysis of these experiments indicates that a substantial fraction of the obtained DD fusion neutron yields {approx} 3 x 10{sup 13}, about 50%, might have been of thermonuclear origin. The goal of our study is to estimate the scaling of the thermonuclear neutron yield from deuterium gas-puff implosions with higher load currents available after the refurbishment of Z, both in the short-pulse ({approx}100 ns) and in the long-pulse ({approx}300 ns) implosion regimes. We report extensive ID and 2D radiation-hydrodynamic simulations of such implosions. The mechanisms of ion heating to the fusion temperatures of 7-10 keV are essentially the same as used in structured gas-puff loads to generate high Ar K-shell yields: shock thermalization of the implosion kinetic energy and subsequent adiabatic heating of the on-axis plasma. We investigate the role of high-atomic-number gas that can be added to the outer shell to improve both energy coupling of the imploded mass to the generator and energy transfer to the inner part of the load, due to radiative losses that make the outer shell thin. We analyze the effect of imposed axial magnetic field {approx}30-100 kG, which can contribute both to stabilization of the implosion and to Joule heating of the imploded plasma. Our estimates indicate that thermonuclear DD neutron yields approaching 10 are within the reach on refurbished Z.

  9. Heat generation above break-even from laser-induced fusion in ultra-dense deuterium

    SciTech Connect

    Holmlid, Leif

    2015-08-15

    Previous results from laser-induced processes in ultra-dense deuterium D(0) give conclusive evidence for ejection of neutral massive particles with energy >10 MeV u{sup −1}. Such particles can only be formed from nuclear processes like nuclear fusion at the low laser intensity used. Heat generation is of interest for future fusion energy applications and has now been measured by a small copper (Cu) cylinder surrounding the laser target. The temperature rise of the Cu cylinder is measured with an NTC resistor during around 5000 laser shots per measured point. No heating in the apparatus or the gas feed is normally used. The fusion process is suboptimal relative to previously published studies by a factor of around 10. The small neutral particles H{sub N}(0) of ultra-dense hydrogen (size of a few pm) escape with a substantial fraction of the energy. Heat loss to the D{sub 2} gas (at <1 mbar pressure) is measured and compensated for under various conditions. Heat release of a few W is observed, at up to 50% higher energy than the total laser input thus a gain of 1.5. This is uniquely high for the use of deuterium as fusion fuel. With a slightly different setup, a thermal gain of 2 is reached, thus clearly above break-even for all neutronicity values possible. Also including the large kinetic energy which is directly measured for MeV particles leaving through a small opening gives a gain of 2.3. Taking into account the lower efficiency now due to the suboptimal fusion process, previous studies indicate a gain of at least 20 during long periods.

  10. Deuterium hyperfine structure in interstellar C3HD

    NASA Technical Reports Server (NTRS)

    Bell, M. B.; Watson, J. K.; Feldman, P. A.; Matthews, H. E.; Madden, S. C.; Irvine, W. M.

    1987-01-01

    The deuterium nuclear quadrupole hyperfine structure of the transition 1(10)-1(01) of the ring molecule cyclopropenylidene-d1 (C3HD) has been observed in emission from interstellar molecular clouds. The narrowest linewidths (approximately 7 kHz) so far observed are in the cloud L1498. The derived D coupling constants Xzz = 186.9(1.4) kHz, eta=0.063(18) agree well with correlations based on other molecules.

  11. Azimuthal asymmetries in DVCS on unpolarized hydrogen and deuterium targets

    SciTech Connect

    Marukyan, H.

    2009-08-04

    We report the latest results of azimuthal asymmetries in the DVCS process measured at the HERMES experiment on unpolarized hydrogen and deuterium targets. Exploiting the ability of HERA to provide lepton beams with both charges and spin orientations, it is possible to extract simultaneously asymmetry amplitudes attributed to the pure DVCS process and to the interference between the Bethe-Heitler and DVCS processes. The results are compared to the theoretical calculations.

  12. Kinetic isotope effects for fast deuterium and proton exchange rates

    PubMed Central

    Mammoli, Daniele; Kadeřávek, Pavel; Pelupessy, Philippe; Bodenhausen, Geoffrey

    2016-01-01

    By monitoring the effect of deuterium decoupling on the decay of transverse 15N magnetization in D–15N spin pairs during multiple-refocusing echo sequences, we have determined fast D–D exchange rates k D and compared them with fast H–H exchange rates k H in tryptophan to determine the kinetic isotope effect as a function of pH and temperature. PMID:27009684

  13. Deuterium Burning in Massive Giant Planets and Low-mass Brown Dwarfs Formed by Core-nucleated Accretion

    NASA Astrophysics Data System (ADS)

    Bodenheimer, Peter; D'Angelo, Gennaro; Lissauer, Jack J.; Fortney, Jonathan J.; Saumon, Didier

    2013-06-01

    Using detailed numerical simulations, we study the formation of bodies near the deuterium-burning limit according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 M ⊕, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (M Jup). After the formation process, which lasts 1-5 Myr and which ends with a "cold-start," low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M 50, above which more than 50% of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M 50 fall in the range 11.6-13.6 M Jup, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yielding lower values of M 50. For masses above M 50, during the deuterium-burning phase, objects expand and increase in luminosity by one to three orders of magnitude. Evolutionary tracks in the luminosity versus time diagram are compared with the observed position of the companion to Beta Pictoris.

  14. Fractional vector calculus and fractional Maxwell's equations

    SciTech Connect

    Tarasov, Vasily E.

    2008-11-15

    The theory of derivatives and integrals of non-integer order goes back to Leibniz, Liouville, Grunwald, Letnikov and Riemann. The history of fractional vector calculus (FVC) has only 10 years. The main approaches to formulate a FVC, which are used in the physics during the past few years, will be briefly described in this paper. We solve some problems of consistent formulations of FVC by using a fractional generalization of the Fundamental Theorem of Calculus. We define the differential and integral vector operations. The fractional Green's, Stokes' and Gauss's theorems are formulated. The proofs of these theorems are realized for simplest regions. A fractional generalization of exterior differential calculus of differential forms is discussed. Fractional nonlocal Maxwell's equations and the corresponding fractional wave equations are considered.

  15. Cryogenic Implosion Performance Using High-Purity Deuterium-Tritium Fuel

    NASA Astrophysics Data System (ADS)

    Sangster, T. C.; Goncharov, V. N.; Radha, P. B.; Earley, R.; Epstein, R.; Forrest, C. J.; Froula, D. H.; Glebov, V. Yu.; Hu, S. X.; Igumenshchev, I. V.; Marshall, F. J.; McKenty, P. W.; Shmayda, W. T.; Shoup, M. J., III; Michel, D. T.; Stoeckl, C.; Seka, W.; Frenje, J. A.; Gatu Johnson, M.

    2014-10-01

    Demonstrating hydrodynamic equivalence between symmetric implosions on OMEGA and National Ignition Facility ignition designs will require a number of facility enhancements that include dynamic bandwidth reduction, a set of higher-order super-Gaussian phase plates, high-spatial-resolution gated-core imaging, high-bandwidth neutron burnwidth measurements, improved power balance, and contaminant-free deuterium-tritium (DT) fuel. The historic DT fuel supply was contaminated with ~6 atm% of 1H, leading to significant fractionation of the fuel during the layering process (the triple points of H:D and H:T are significantly colder than DD, DT, and TT). The fractionation leads to a drop in the potential yield because the D and T number densities are lower in the void than they would be with a pure-DT mixture). An isotope separation system has been developed to remove the 1H from the DT fuel supply. This talk will discuss the first results with the purified fuel, conclusions from recent implosions to test cross-beam energy transfer mitigation, and the status of the remaining facility enhancements. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  16. The effect of beryllium on deuterium implantation in tungsten by atomistic simulations

    NASA Astrophysics Data System (ADS)

    Lasa, A.; Heinola, K.; Nordlund, K.

    2014-12-01

    Tungsten (W) and beryllium (Be) have been chosen as plasma-facing materials for the ITER reactor and the main fuel component will be deuterium (D). Due to plasma-wall interactions, these materials will immediately mix via erosion, transport and re-deposition. We present the first atomistic study on the effect of D co-implanted with Be into W, by modelling D plus Be irradiation of W surfaces, at projectile energies and compositions relevant for the plasma-wall interactions. The D implantation and Be sticking yields increased with the Be fraction in the system, especially at the lowest energies, as a Be layer was deposited on the surface. Tungsten was sputtered by Be, although the yield was partially suppressed by the deposited Be-D layer, and the Be erosion was determined by the balance between the Be concentration at the surface and projectile energy. Molecules were also sputtered: a large fraction of the D is reflected as D2, and purely metallic molecules (Be2, BeW) as well as different Be-D compounds were sputtered. On the other hand, the D clustered when implanted in or beneath a pre-deposited Be-W layer.

  17. Deuterium off-resonance rotating frame spin-lattice relaxation of macromolecular bound ligands.

    PubMed Central

    Rydzewski, J M; Schleich, T

    1996-01-01

    Deuterated 3-trimethylsilylpropionic acid binding to bovine serum albumin was used as a model system to examine the feasibility and limitations of using the deuterium off-resonance rotating frame spin-lattice relaxation experiment for the study of equilibrium ligand-binding behavior to proteins. The results of this study demonstrate that the rotational-diffusion behavior of the bound species can be monitored directly, i.e., the observed correlation time of the ligand in the presence of a protein is approximately equal to the correlation time of the ligand in the bound state, provided that the fraction of bound ligand is at least 0.20. The presence of local ligand motion and/or chemical exchange contributions to relaxation in the bound state was inferred from the observation that the correlation time of the bound ligand was somewhat smaller than the correlation time characterizing the overall tumbling of the protein. An approximate value for the fraction of bound ligand was obtained from off-resonance relaxation experiments when supplemental spin-lattice or transverse relaxation times were employed in the analysis. Incorporation of local motion effects for the bound species into the theoretical relaxation formalism enabled the evaluation of an order parameter and an effective correlation time, which in conjunction with a wobbling in a cone model, provided additional information about ligand motion in the bound state. PMID:8785304

  18. Deuterium REDOR: Principles and Applications for Distance Measurements

    NASA Astrophysics Data System (ADS)

    Sack, I.; Goldbourt, A.; Vega, S.; Buntkowsky, G.

    1999-05-01

    The application of short composite pulse schemes ([figure] and [figure]) to the rotational echo double-resonance (REDOR) spectroscopy ofX-2H (X: spin{1}/{2}, observed) systems with large deuterium quadrupolar interactions has been studied experimentally and theoretically and compared with simple 180° pulse schemes. The basic properties of the composite pulses on the deuterium nuclei have been elucidated, using average Hamiltonian theory, and exact simulations of the experiments have been achieved by stepwise integration of the equation of motion of the density matrix. REDOR experiments were performed on15N-2H in doubly labeled acetanilide and on13C-2H in singly2H-labeled acetanilide. The most efficient REDOR dephasing was observed when [figure] composite pulses were used. It is found that the dephasing due to simple 180° deuterium pulses is about a factor of 2 less efficient than the dephasing due to the composite pulse sequences and thus the range of couplings observable byX-2H REDOR is enlarged toward weaker couplings, i.e., larger distances. From these experiments the2H-15N dipolar coupling between the amino deuteron and the amino nitrogen and the2H-13C dipolar couplings between the amino deuteron and the α and β carbons have been elucidated and the corresponding distances have been determined. The distance data from REDOR are in good agreement with data from X-ray and neutron diffraction, showing the power of the method.

  19. The Advanced Neutron Source liquid deuterium cold source

    SciTech Connect

    Lucas, A.T.

    1995-08-01

    The Advanced Neutron Source will employ two cold sources to moderate neutrons to low energy (<10 meV). The cold neutrons produced are then passed through beam guides to various experiment stations. Each cold source moderator is a sphere of 410-mm internal diameter. The moderator material is liquid deuterium flowing at a rate of 1 kg/s and maintained at subcooled temperatures at all points of the circuit, to prevent boiling. Nuclear beat deposited within the liquid deuterium and its containment structure totals more than 30 kW. All of this heat is removed by the liquid deuterium, which raises its temperature by 5 K. The liquid prime mover is a cryogenic circulator that is situated in the return leg of the flow loop. This arrangement minimizes the heat added to the liquid between the heat exchanger and the moderator vessel, allowing the moderator to be operated at the minimum practical temperature. This report describes the latest thinking at the time of project termination. It also includes the status of various systems at that time and outlines anticipated directions in which the design would have progressed. In this regard, some detail differences between this report and official design documents reflect ideas that were not approved at the time of closure but are considered noteworthy.

  20. Cryogenic distillation facility for isotopic purification of protium and deuterium

    NASA Astrophysics Data System (ADS)

    Alekseev, I.; Arkhipov, Ev.; Bondarenko, S.; Fedorchenko, O.; Ganzha, V.; Ivshin, K.; Kammel, P.; Kravtsov, P.; Petitjean, C.; Trofimov, V.; Vasilyev, A.; Vasyanina, T.; Vorobyov, A.; Vznuzdaev, M.

    2015-12-01

    Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.

  1. Cryogenic distillation facility for isotopic purification of protium and deuterium

    SciTech Connect

    Alekseev, I.; Arkhipov, Ev.; Bondarenko, S.; Fedorchenko, O.; Ganzha, V.; Ivshin, K.; Kravtsov, P. Trofimov, V.; Vasilyev, A.; Vasyanina, T.; Vorobyov, A.; Vznuzdaev, M.; Kammel, P.; Petitjean, C.

    2015-12-15

    Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.

  2. The water, deuterium, gas and uranium content of tektites

    USGS Publications Warehouse

    Friedman, I.

    1958-01-01

    The water content, deuterium concentration of the water, total gas and uranium contents were determined on tektite samples and other glass samples from Texas, Australia, Philippine Islands, Java, French Indo-China, Czechoslovakia, Libyan Desert, Billiton Island, Thailand, French West Africa, Peru, and New Mexico. The water content ranges from 0.24 per cent for the Peru tektite, to 0.0002 per cent for a moldavite. The majority of the tektites have less than 0.05 per cent water, and average 0.005 per cent H2O by weight. No other gases were detected, the lower detection limit being about 1 p.p.m. by weight. The deuterium content of the water in tektites is in the same range as that in terrestrial waters, and varies from 0.010 mole per cent to 0.0166 mole per cent deuterium. The uranium content is about from 1 to 3 p.p.m. The possible origin of tektites is discussed. The experimental data presented favour their being originally terrestrial, but produced by some catastrophic event. An extra-terrestrial source is not ruled out. ?? 1958.

  3. A Deuterium NMR Study of Bent-Core Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Dingemans, Theo J.; Madsen, Louis A.; Samulski, Edward T.

    2002-10-01

    We have synthesized two deuterated boomerang-shaped liquid crystals based on 2,5-bis(4-hydroxyphenyl)-1,3,4-oxadiazole (ODBP). Deuterium was introduced in the rigid 2,5-diphenyl-1,3,4-oxadiazole core and in the aromatic ring of the terminal 4-dodecyloxyphenyl moiety using standard acid catalyzed deuterium exchange conditions. Both compounds, (4,4'(1,3,4-oxadiazole-2,5-diyl-d4) di-4-dodecyloxybenzoate: ODBP-d4-Ph-O-C12) and (4,4'(1,3,4-oxadiazole-2,5-diyl) di-4-dodecyloxy-benzoate-d4; ODBP-Ph-d4-O-C12) were investigated by nuclear magnetic resonance, optical microscopy and differential scanning calorimetry. The optical textures and thermal behavior of both compounds were found to be identical to the non-deuterated analog 4,4(1,3,4-oxadiazole-2,5-diyl) di-4-dodecyloxybenzoate (ODBP-Ph-O-C12) which we reported earlier. These compounds exhibit behavior indicative of a biaxial nematic liquid crystal phase, which we hope to confirm using deuterium NMR spectroscopy in the next phase of this study.

  4. Selective deuterium ion acceleration using the Vulcan petawatt laser

    SciTech Connect

    Krygier, A. G.; Morrison, J. T.; Kar, S. Ahmed, H.; Alejo, A.; Green, A.; Jung, D.; Clarke, R.; Notley, M.; Fuchs, J.; Vassura, L.; Kleinschmidt, A.; Roth, M.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Oliver, M.; Zepf, M.; Borghesi, M.; Freeman, R. R.

    2015-05-15

    We report on the successful demonstration of selective acceleration of deuterium ions by target-normal sheath acceleration (TNSA) with a high-energy petawatt laser. TNSA typically produces a multi-species ion beam that originates from the intrinsic hydrocarbon and water vapor contaminants on the target surface. Using the method first developed by Morrison et al. [Phys. Plasmas 19, 030707 (2012)], an ion beam with >99% deuterium ions and peak energy 14 MeV/nucleon is produced with a 200 J, 700 fs, >10{sup 20}W/cm{sup 2} laser pulse by cryogenically freezing heavy water (D{sub 2}O) vapor onto the rear surface of the target prior to the shot. Within the range of our detectors (0°–8.5°), we find laser-to-deuterium-ion energy conversion efficiency of 4.3% above 0.7 MeV/nucleon while a conservative estimate of the total beam gives a conversion efficiency of 9.4%.

  5. High resolution deuterium NMR studies of bacterial metabolism

    SciTech Connect

    Aguayo, J.B.; Gamcsik, M.P.; Dick, J.D.

    1988-12-25

    High resolution deuterium NMR spectra were obtained from suspensions of five bacterial strains: Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus. Deuterium-labeled D-glucose at C-1, C-2, and C-6 was used to monitor dynamically anaerobic metabolism. The flux of glucose through the various bacterial metabolic pathways could be determined by following the disappearance of glucose and the appearance of the major end products in the 2H NMR spectrum. The presence of both labeled and unlabeled metabolites could be detected using 1H NMR spectroscopy since the proton resonances in the labeled species are shifted upfield due to an isotopic chemical shift effect. The 1H-1H scalar coupling observed in both the 2H and 1H NMR spectra was used to assign definitively the resonances of labeled species. An increase in the intensity of natural abundance deuterium signal of water can be used to monitor pathways in which a deuteron is lost from the labeled metabolite. The steps in which label loss can occur are outlined, and the influence these processes have on the ability of 2H NMR spectroscopy to monitor metabolism are assessed.

  6. Equation of motion using fractional calculus

    SciTech Connect

    Kihong, Kwon.

    1991-01-01

    One-dimensional motion of a particle was studied using fractional calculus, which is the differentiation and the integration of arbitrary order. By fractional differentiation, equation of motion could be written in compact form. Fractional parameters were numerically calculated by using the known solutions of general relativistic free fall motion. Also, from the approximate forms for fractional parameters, the physical meanings were found. The fractional parameters depended on the proper time, the mass of gravitating body, and the initial radial coordinate of the particle.

  7. Initialized Fractional Calculus

    NASA Technical Reports Server (NTRS)

    Lorenzo, Carl F.; Hartley, Tom T.

    2000-01-01

    This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.

  8. Concentration and removal of tritium and/or deuterium from water contaminated with tritium and/or deuterium

    DOEpatents

    Meyer, Thomas J.; Narula, Poonam M.

    2001-01-01

    Concentration of tritium and/or deuterium that is a contaminant in H.sub.2 O, followed by separation of the concentrate from the H.sub.2 O. Employed are certain metal oxo complexes, preferably with a metal from Group VIII. For instance, [Ru.sup.IV (2,2',6',2"-terpyridine)(2,2'-bipyridine)(O)](ClO.sub.4).sub.2 is very suitable.

  9. On the abundance of deuterium in celestial objects

    NASA Astrophysics Data System (ADS)

    Lundin, Rickard; Kero, Johan; Liszka, Ludwik

    2016-04-01

    The deuterium hydrogen ratio (D/H) is the subject of conflicting ideas about the origin of water on the Earth. The present D/H ratio in the Earth oceans (≈1.5x10-4) is substantially lower than most, if not all potential cosmic sources. Furthermore, other celestial bodies, including interstellar space, display a fairly wide range of D/H ratios superseding the terrestrial one. Escape processes may in part explain higher D/H ratios on Mars and Venus, but cannot explain the Earth's low ratio compared to that of the potential sources (e.g. comets and meteors), unless a deuterium "removal" process can be inferred that reduces the D/H ratio. Alternatively, the D/H ratio in the Earth's ocean represents a time capsule of a yet to be identified cosmic source. It is here hypothesized that the former is the cause, a "removal" of deuterium in matter (carbohydrates, water etc.) having high (pristine) D/H ratios. By "removal" is here meant an isotope transmutation, i.e. deuterium is transmuted to hydrogen plus a thermal neutron, a process requiring >2.25 MeV (≈3.6·10-13 J). However, once released a thermal neutron will eventually fuse with another heavier element by thermal neutron capture, a process that may lead to energy in excess of the spallation energy. The energy gain differs for different isotopes, but if exceeding unity it will induce more heat/power than the input power, maintaining power production over time. A gain less than unity will still result in deuterium removal, but also isotope transmutation, and/or element transmutation via β± decay. This report gives a theoretical background for the plasma forcing that can lead to thermal neutron spallation, a process that changes/decrease the D/H ratio in celestial objects. The applicability of the theory will be tested on celestial objects subjected to strong dynamic, and electromagnetic forcing, by the Sun or during the entry of high-speed objects into the Eart&hacute;s atmosphere.

  10. On the abundance of deuterium in celestial objects

    NASA Astrophysics Data System (ADS)

    Lundin, Rickard; Kero, Johan; Liszka, Ludwik

    2016-04-01

    The deuterium hydrogen ratio (D/H) is the subject of conflicting ideas about the origin of water on the Earth. The present D/H ratio in the Earth oceans (≈1.5x10-4) is substantially lower than most, if not all potential cosmic sources. Furthermore, other celestial bodies, including interstellar space, display a fairly wide range of D/H ratios superseding the terrestrial one. Escape processes may in part explain higher D/H ratios on Mars and Venus, but cannot explain the Earth's low ratio compared to that of the potential sources (e.g. comets and meteors), unless a deuterium "removal" process can be inferred that reduces the D/H ratio. Alternatively, the D/H ratio in the Earth's ocean represents a time capsule of a yet to be identified cosmic source. It is here hypothesized that the former is the cause, a "removal" of deuterium in matter (carbohydrates, water etc.) having high (pristine) D/H ratios. By "removal" is here meant an isotope transmutation, i.e. deuterium is transmuted to hydrogen plus a thermal neutron, a process requiring >2.25 MeV (≈3.6·10-13 J). However, once released a thermal neutron will eventually fuse with another heavier element by thermal neutron capture, a process that may lead to energy in excess of the spallation energy. The energy gain differs for different isotopes, but if exceeding unity it will induce more heat/power than the input power, maintaining power production over time. A gain less than unity will still result in deuterium removal, but also isotope transmutation, and/or element transmutation via β± decay. This report gives a theoretical background for the plasma forcing that can lead to thermal neutron spallation, a process that changes/decrease the D/H ratio in celestial objects. The applicability of the theory will be tested on celestial objects subjected to strong dynamic, and electromagnetic forcing, by the Sun or during the entry of high-speed objects into the Earth's atmosphere.

  11. Development of a new deuterium-deuterium (D-D) neutron generator for prompt gamma-ray neutron activation analysis.

    PubMed

    Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

    2014-12-01

    A new deuterium-deuterium (D-D) neutron generator has been developed by Adelphi Technology for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA), and fast neutron radiography. The generator makes an excellent fast, intermediate, and thermal neutron source for laboratories and industrial applications that require the safe production of neutrons, a small footprint, low cost, and small regulatory burden. The generator has three major components: a Radio Frequency Induction Ion Source, a Secondary Electron Shroud, and a Diode Accelerator Structure and Target. Monoenergetic neutrons (2.5MeV) are produced with a yield of 10(10)n/s using 25-50mA of deuterium ion beam current and 125kV of acceleration voltage. The present study characterizes the performance of the neutron generator with respect to neutron yield, neutron production efficiency, and the ionic current as a function of the acceleration voltage at various RF powers. In addition the Monte Carlo N-Particle Transport (MCNP) simulation code was used to optimize the setup with respect to thermal flux and radiation protection. PMID:25305524

  12. Structural Transformations in Austenitic Stainless Steel Induced by Deuterium Implantation: Irradiation at 295 K.

    PubMed

    Morozov, Oleksandr; Zhurba, Volodymir; Neklyudov, Ivan; Mats, Oleksandr; Progolaieva, Viktoria; Boshko, Valerian

    2016-12-01

    Deuterium thermal desorption spectra were investigated on the samples of austenitic steel 18Cr10NiTi pre-implanted at 295 K with deuterium ions in the dose range from 8 × 10(14) to 2.7 × 10(18) D/cm(2). The kinetics of structural transformation development in the steel layer was traced from deuterium thermodesorption spectra as a function of deuterium concentration. Three characteristic regions with different low rates of deuterium amount desorption as the implantation dose increases were revealed: I-the linear region of low implantation doses (up to 1 × 10(17) D/cm(2)); II-the nonlinear region of medium implantation doses (1 × 10(17) to 8 × 10(17) D/cm(2)); III-the linear region of high implantation doses (8 × 10(17) to 2.7 × 10(18) D/cm(2)). During the process of deuterium ion irradiation, the coefficient of deuterium retention in steel varies in discrete steps. Each of the discrete regions of deuterium retention coefficient variation corresponds to different implanted-matter states formed during deuterium ion implantation. The low-dose region is characterized by formation of deuterium-vacancy complexes and solid-solution phase state of deuterium in the steel. The total concentration of the accumulated deuterium in this region varies between 2.5 and 3 at.%. The medium-dose region is characterized by the radiation-induced action on the steel in the presence of deuterium with the resulting formation of the energy-stable nanosized crystalline structure of steel, having a developed network of intercrystalline boundaries. The basis for this developed network of intercrystalline boundaries is provided by the amorphous state, which manifests itself in the thermodesorption spectra as a widely temperature-scale extended region of deuterium desorption (structure formation with a varying activation energy). The total concentration of the accumulated deuterium in the region of medium implantation doses makes 7 to 8 at.%. The

  13. Structural Transformations in Austenitic Stainless Steel Induced by Deuterium Implantation: Irradiation at 295 K

    NASA Astrophysics Data System (ADS)

    Morozov, Oleksandr; Zhurba, Volodymir; Neklyudov, Ivan; Mats, Oleksandr; Progolaieva, Viktoria; Boshko, Valerian

    2016-02-01

    Deuterium thermal desorption spectra were investigated on the samples of austenitic steel 18Cr10NiTi pre-implanted at 295 K with deuterium ions in the dose range from 8 × 1014 to 2.7 × 1018 D/cm2. The kinetics of structural transformation development in the steel layer was traced from deuterium thermodesorption spectra as a function of deuterium concentration. Three characteristic regions with different low rates of deuterium amount desorption as the implantation dose increases were revealed: I—the linear region of low implantation doses (up to 1 × 1017 D/cm2); II—the nonlinear region of medium implantation doses (1 × 1017 to 8 × 1017 D/cm2); III—the linear region of high implantation doses (8 × 1017 to 2.7 × 1018 D/cm2). During the process of deuterium ion irradiation, the coefficient of deuterium retention in steel varies in discrete steps. Each of the discrete regions of deuterium retention coefficient variation corresponds to different implanted-matter states formed during deuterium ion implantation. The low-dose region is characterized by formation of deuterium-vacancy complexes and solid-solution phase state of deuterium in the steel. The total concentration of the accumulated deuterium in this region varies between 2.5 and 3 at.%. The medium-dose region is characterized by the radiation-induced action on the steel in the presence of deuterium with the resulting formation of the energy-stable nanosized crystalline structure of steel, having a developed network of intercrystalline boundaries. The basis for this developed network of intercrystalline boundaries is provided by the amorphous state, which manifests itself in the thermodesorption spectra as a widely temperature-scale extended region of deuterium desorption (structure formation with a varying activation energy). The total concentration of the accumulated deuterium in the region of medium implantation doses makes 7 to 8 at.%. The resulting structure shows stability against the action of

  14. A Fractional Variational Approach to the Fractional Basset-Type Equation

    NASA Astrophysics Data System (ADS)

    Baleanu, Dumitru; Garra, Roberto; Petras, Ivo

    2013-08-01

    In this paper we discuss an application of fractional variational calculus to the Basset-type fractional equations. It is well known that the unsteady motion of a sphere immersed in a Stokes fluid is described by an integro-differential equation involving derivative of real order. Here we study the inverse problem, i.e. we consider the problem from a Lagrangian point of view in the framework of fractional variational calculus. In this way we find an application of fractional variational methods to a classical physical model, finding a Basset-type fractional equation starting from a Lagrangian depending on derivatives of fractional order.

  15. Soot Volume Fraction Imaging

    NASA Technical Reports Server (NTRS)

    Greenberg, Paul S.; Ku, Jerry C.

    1994-01-01

    A new technique is described for the full-field determination of soot volume fractions via laser extinction measurements. This technique differs from previously reported point-wise methods in that a two-dimensional array (i.e., image) of data is acquired simultaneously. In this fashion, the net data rate is increased, allowing the study of time-dependent phenomena and the investigation of spatial and temporal correlations. A telecentric imaging configuration is employed to provide depth-invariant magnification and to permit the specification of the collection angle for scattered light. To improve the threshold measurement sensitivity, a method is employed to suppress undesirable coherent imaging effects. A discussion of the tomographic inversion process is provided, including the results obtained from numerical simulation. Results obtained with this method from an ethylene diffusion flame are shown to be in close agreement with those previously obtained by sequential point-wise interrogation.

  16. Determination of hydrogen/deuterium ratio with neutron measurements on MAST

    SciTech Connect

    Klimek, I. Cecconello, M.; Ericsson, G.; Sharapov, S. E.; Harrison, J.

    2014-11-15

    On MAST, compressional Alfvén eigenmodes can be destabilized by the presence of a sufficiently large population of energetic particles in the plasma. This dependence was studied in a series of very similar discharges in which increasing amounts of hydrogen were puffed into a deuterium plasma. A simple method to estimate the isotopic ratio n{sub H}/n{sub D} using neutron emission measurements is here described. The inferred isotopic ratio ranged from 0.0 to 0.6 and no experimental indication of changes in radial profile of n{sub H}/n{sub D} were observed. These findings are confirmed by TRANSP/NUBEAM simulations of the neutron emission.

  17. Saturation and isotopic replacement of deuterium in low-Z material

    SciTech Connect

    Doyle, B.L.; Wampler, W.R.; Brice, D.K.; Picraux, S.T.

    1980-01-01

    The saturation and replacement of hydrogen isotopes implanted into TiC, TiB/sub 2/, VB/sub 2/, B/sub 4/C, B, Si, and C has been examined experimentally and modeled theoretically. The deuterium saturation concentrations for these materials varied from .16 to .57. A new isotopic replacement model is presented which predicts isotopic trapping and exchange on the basis of the depth dependence of the implanted ions and the experimentally determined hydrogen saturation concentration. Our results indicate that, for these materials used as coatings on components in a D-T fueled tokamak, T recovery by ion induced replacement with H or D should be feasible and that T buildup will be at tolerable levels.

  18. Determination of deuterium-tritium critical burn-up parameter by four temperature theory

    NASA Astrophysics Data System (ADS)

    Nazirzadeh, M.; Ghasemizad, A.; Khanbabei, B.

    2015-12-01

    Conditions for thermonuclear burn-up of an equimolar mixture of deuterium-tritium in non-equilibrium plasma have been investigated by four temperature theory. The photon distribution shape significantly affects the nature of thermonuclear burn. In three temperature model, the photon distribution is Planckian but in four temperature theory the photon distribution has a pure Planck form below a certain cut-off energy and then for photon energy above this cut-off energy makes a transition to Bose-Einstein distribution with a finite chemical potential. The objective was to develop four temperature theory in a plasma to calculate the critical burn up parameter which depends upon initial density, the plasma components initial temperatures, and hot spot size. All the obtained results from four temperature theory model are compared with 3 temperature model. It is shown that the values of critical burn-up parameter calculated by four temperature theory are smaller than those of three temperature model.

  19. Effect of noble gas ion pre-irradiation on deuterium retention in tungsten

    NASA Astrophysics Data System (ADS)

    Cheng, L.; Zhao, Z. H.; De Temmerman, G.; Yuan, Y.; Morgan, T. W.; Guo, L. P.; Wang, B.; Zhang, Y.; Wang, B. Y.; Zhang, P.; Cao, X. Z.; Lu, G. H.

    2016-02-01

    Impurity seeding of noble gases is an effective way of decreasing the heat loads onto the divertor targets in fusion devices. To investigate the effect of noble gases on deuterium retention, tungsten targets have been implanted by different noble gas ions and subsequently exposed to deuterium plasma. Irradiation induced defects and deuterium retention in tungsten targets have been characterized by positron annihilation Doppler broadening and thermal desorption spectroscopy. Similar defect distributions are observed in tungsten irradiated by neon and argon, while it is comparatively low in the case of helium. The influence of helium pre-irradiation on deuterium trapping is found to be small based on the desorption spectrum compared with that of the pristine one. Neon and argon pre-irradiation leads to an enhancement of deuterium trapping during plasma exposure. The influence on deuterium retention is found to be argon > neon > helium when comparing at a similar crystal damage level.

  20. Deuterium content of H2 measured on air samples from the CARIBIC project

    NASA Astrophysics Data System (ADS)

    Batenburg, A. M.; Schuck, T.; Brenninkmeijer, C. A. M.; Röckmann, T.

    2009-04-01

    H2 is present in the atmosphere at levels of ~500 ppb; its largest sources are the oxidation of methane and other hydrocarbons and combustion processes. In the coming decades, H2 levels are expected to rise due to use of hydrogen as an energy carrier. This may affect methane lifetimes and stratospheric ozone depletion. Unfortunately, large uncertainties still exist in the global H2budget. The different sources and sinks of H2 have very distinct isotopic signatures and fractionation coefficients, respectively. For this reason, measurements of isotopic composition are a promising tool to gain insight into H2 source and sink processes and to constrain the terms in the global budget. The CARIBIC project uses an automated instrument container on board of a commercial passenger aircraft to carry out in situ measurements of trace gases and aerosols and to collect air samples. The use of a commercial airliner results in samples mostly from the Upper Troposphere-Lower Stratosphere (UTLS) region. Although the UTLS region is considered to be an interesting part of the atmosphere, relatively few measurements have been made there before. The CARIBIC samples are routinely analyzed for various gases, including four important greenhouse gases. In addition, air samples of 15 CARIBIC flights have now been analyzed for molecular hydrogen concentration (H2) and H2 deuterium content (^D-H2) in the isotope laboratory of the Institute of Marine and Atmospheric Research Utrecht (IMAU). A GC-IRMS system (similar to Rhee et al. [2004]) is used to determine the concentration and deuterium content of atmospheric H2 precisely and routinely. This poster will present a selection of the first results. For some flights, samples close to the takeoff and landing region show strong contamination signatures (high H2 concentrations and low ^D-H2 values). With the exclusion of these samples, ^D values correlate negatively with methane concentration, as observed previously by Rahn et al. [2003] and R

  1. Long Term Retention of Deuterium and Tritium in Alcator C-Mod

    SciTech Connect

    FIORE,C.; LABOMBARD,B.; LIPSCHULTZ,B.; PITCHER,C.S.; SKINNER,C.H.; WAMPLER,WILLIAM R.

    1999-11-03

    We estimate the total in-vessel deuterium retention in Alcator C-Mod from a run campaign of about 1090 plasmas. The estimate is based on measurements of deuterium retained on 22 molybdenum tiles from the inner wall and divertor. The areal density of deuterium on the tiles was measured by nuclear reaction analysis. From these data, the in-vessel deuterium inventory is estimated to be about 0.1 gram, assuming the deuterium coverage is toroidally symmetric. Most of the retained deuterium is on the walls of the main plasma chamber, only about 2.5% of the deuterium is in the divertor. The D coverage is consistent with a layer saturated by implantation with ions and charge-exchange neutrals from the plasma. This contrasts with tokamaks with carbon plasma-facing components (PFC's) where long-term retention of tritium and deuterium is large and mainly in the divertor due to codeposition with carbon eroded by the plasma. The low deuterium retention in the C-Mod divertor is mainly due to the absence of carbon PFC's in C-Mod and the low erosion rate of Mo.

  2. Lattice location of deuterium in plasma and gas charged Mg doped GaN

    SciTech Connect

    Wampler, W.R.; Barbour, J.C.; Seager, C.H.; Myers, S.M. Jr.; Wright, A.F.; Han, J.

    1999-12-02

    The authors have used ion channeling to examine the lattice configuration of deuterium in Mg doped GaN grown by MOCVD. The deuterium is introduced both by exposure to deuterium gas and to ECR plasmas. A density functional approach including lattice relaxation, was used to calculate total energies for various locations and charge states of hydrogen in the wurtzite Mg doped GaN lattice. Computer simulations of channeling yields were used to compare results of channeling measurements with calculated yields for various predicted deuterium lattice configurations.

  3. FRACTIONAL INTEGRATION TOOLBOX

    PubMed Central

    Marinov, Toma M.; Ramirez, Nelson; Santamaria, Fidel

    2014-01-01

    The problems formulated in the fractional calculus framework often require numerical fractional integration/differentiation of large data sets. Several existing fractional control toolboxes are capable of performing fractional calculus operations, however, none of them can efficiently perform numerical integration on multiple large data sequences. We developed a Fractional Integration Toolbox (FIT), which efficiently performs fractional numerical integration/differentiation of the Riemann-Liouville type on large data sequences. The toolbox allows parallelization and is designed to be deployed on both CPU and GPU platforms. PMID:24812536

  4. Pyrolysis compound specific isotopic analysis (δ13C and δD Py-CSIA) of soil organic matter size fractions under four vegetation covers.

    NASA Astrophysics Data System (ADS)

    Jiménez-Morillo, Nicasio T.; González-Vila, Francisco J.; Almendros, Gonzalo; De la Rosa, José M.; González-Pérez, José A.

    2015-04-01

    specific SOM compounds released directly from pyrolysis (Py-CSIA); lipids (Alkenes), aromatic unspecific (alkylphenols), lignin (methoxyphenols) and polysaccharides (anhydrosugars) derived molecules. For all coarse fractions the δ13C and δD values had the same general behavior with sugar derived molecules being enriched in the heavy isotope. Regarding alkenes δ13C isotopic signature, this was variable and dependent upon the main cover vegetation that may reflect different fractionations at different synthesis stages (Chikaraishi & Naraoka, 2001), The δD values for specific compounds had a similar behavior to that for δ13C, being the sugar derived compounds the most deuterium enriched in comparison with lipid and lignin derived pyrolysis products. A conspicuous δD fractionation was observed for the sugar derived compounds in the fine fractions as compared with the coarse ones, with a depletion in deuterium, mainly for the PA sample where the depletion was the highest (c. -140 ‰). This may points to the occurrence of biological reworking with a higher microbiological activity fixing the lighter isotope in the soil fine organic fractions. It is known that lipid hydrogen is deuterium depleted relative to bulk organic hydrogen (Smith and Epstein, 1970). In line with this, in our study the lipid derived compounds had the largest deuterium depleted signature with a difference between bulk and lipid δD values was c. -35‰. This fractionation was highest in Pine (PP) and Rockrose (HH). The combination of traditional techniques for the study of SOM i.e. Py-GC/MS and IRMS, with new hyphenated analytical pyrolysis techniques i.e. Py-CSIA opens new possibilities and windows of information in SOM research. Our findings points to the occurrence of more or less complex processes that affects SOM chemical characteristics; whereas the coarse fraction resembles the chemical structure of the above vegetation, this SOM "memory" is less defined in the fine fractions, probably due to

  5. Electron Scattering From High-Momentum Neutrons in Deuterium

    SciTech Connect

    A.V. Klimenko; S.E. Kuhn

    2005-10-12

    We report results from an experiment measuring the semi-inclusive reaction D(e,e'p{sub s}) where the proton p{sub s} is moving at a large angle relative to the momentum transfer. If we assume that the proton was a spectator to the reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred. This method, known as spectator tagging, can be used to study electron scattering from high-momentum (off-shell) neutrons in deuterium. The data were taken with a 5.765 GeV electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section was extracted for different values of final-state missing mass W*, backward proton momentum {rvec p}{sub s} and momentum transfer Q{sup 2}. The data are compared to a simple PWIA spectator model. A strong enhancement in the data observed at transverse kinematics is not reproduced by the PWIA model. This enhancement can likely be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. A ''bound neutron structure function'' F{sub 2n}{sup eff} was extracted as a function of W* and the scaling variable x* at extreme backward kinematics, where effects of FSI appear to be smaller. For p{sub s} > 400 MeV/c, where the neutron is far off-shell, the model overestimates the value of F{sub 2n}{sup eff} in the region of x* between 0.25 and 0.6. A modification of the bound neutron structure function is one of possible effects that can cause the observed deviation.

  6. UCN Production With a Single Crystal of Ortho-Deuterium

    PubMed Central

    Utsuro, M.; Tanaka, M.; Mishima, K.; Nagai, Y.; Shima, T.; Fukuda, Y.; Kohmoto, T.; Momose, T.; Moriai, A.; Okumura, K.; Yoshino, H.

    2005-01-01

    The present paper reports on the preliminary experimental results concerning a new concept of ultracold neutron production with a single crystal converter of ortho-deuterium lying in the ground rotational state at the low temperature of about 10 K, which should make it possible to utilize a guided cold neutron beam instead of irradiating the converter material in the inside of high radiation fields. The successful observation of the clear Bragg scattering pattern from the single crystal converter and the reasonable results from the first experimental trial of the ultracold neutron production with the single crystal are shown. PMID:27308135

  7. UCN Production With a Single Crystal of Ortho-Deuterium.

    PubMed

    Utsuro, M; Tanaka, M; Mishima, K; Nagai, Y; Shima, T; Fukuda, Y; Kohmoto, T; Momose, T; Moriai, A; Okumura, K; Yoshino, H

    2005-01-01

    The present paper reports on the preliminary experimental results concerning a new concept of ultracold neutron production with a single crystal converter of ortho-deuterium lying in the ground rotational state at the low temperature of about 10 K, which should make it possible to utilize a guided cold neutron beam instead of irradiating the converter material in the inside of high radiation fields. The successful observation of the clear Bragg scattering pattern from the single crystal converter and the reasonable results from the first experimental trial of the ultracold neutron production with the single crystal are shown. PMID:27308135

  8. Modeling deuterium chemistry of interstellar space with large chemical networks

    NASA Astrophysics Data System (ADS)

    Albertsson, T.; Semenov, D. A.; Vasyunin, A. I.; Henning, Th.; Herbst, E.

    2015-03-01

    Observations of deuterated species are essential to probing the properties and thermal history of various astrophysical environments, and the ALMA observing facilities will reveal a multitude of new deuterated molecules. To analyze these new vast data we have constructed a new up-to-date network with the largest collection of deuterium chemistry reactions to date. We assess the reliability of the network and probe the role of physical parameters and initial abundances on the chemical evolution of deuterated species. Finally, we perform a sensitivity study to assess the uncertainties in the estimated abundances and D/H ratios.

  9. Identification of deuterium ions in the ionosphere of Venus

    NASA Technical Reports Server (NTRS)

    Hartle, R. E.; Taylor, H. A., Jr.

    1983-01-01

    The dominant mass two ion in the ionosphere of Venus is identified as D(+) through analysis of the height variation of (mass two ion)/(H(+)) measured in the chemical equilibrium region by the ion mass spectrometer on the Pioneer Venus Orbiter. This result leads to (D)/(H) = (2.2 + or - 0.6) x 10 to the -2 at the turbopause, which agrees with the ratio measured in the lower atmosphere by the large probe mass spectrometer. The 100-fold deuterium enrichment supports previous suggestions that Venus has lost at least 0.3 percent of a terrestrial ocean.

  10. Interaction of graphite with a hot, dense deuterium plasma

    SciTech Connect

    Desko, J.C. Jr.

    1980-01-01

    The erosion of ATJ-S graphite caused by a hot, dense deuterium plasma has been investigated experimentally. The plasma was produced in an electromagnetic shock tube. Plasma characteristics were typically: ion temperature approx. = 800 eV (approx. 1 x 10/sup 7/ /sup 0/K), number density approx. = 10/sup 16//cm/sup 3/, and transverse magnetic field approx. = 1 tesla. The energetic ion flux, phi, to the sample surfaces was approx. 10/sup 23/ ions/cm/sup 2/-sec for a single pulse duration of approx. 0.1 usec. Sample surfaces were metallographically prepared and examined with a scanning electron microscope before and after exposure.

  11. Development of an optically pumped polarized deuterium target

    SciTech Connect

    Young, L.; Holt, R.J.; Green, M.C.; Kowalczyk, R.

    1987-01-01

    The development of a polarized deuterium target for internal use at an electron storage ring is of great interest for fundamental studies in nuclear physics. In order to achieve the maximum allowable target thickness, 10/sup 14/ nuclei/cm/sup 2/, consistent with various constraints imposed by the storage ring environment, a flux of 4 x 10/sup 17/ polarized atom/s must be provided. This flux exceeds the capability of conventional atomic beam sources by an order of magnitude. We have been developing an alternative source based upon the spin-exchange optical pumping method in which the flux is limited only by laser power. 7 refs., 1 fig.

  12. Electron Scattering From a High-Momentum Neutron in Deuterium

    SciTech Connect

    Alexei Klimenko

    2004-05-01

    The deuterium nucleus is a system of two nucleons (proton and neutron) bound together. The configuration of the system is described by a quantum-mechanical wave function and the state of the nucleons at a given time is not know a priori. However, by detecting a backward going proton of moderate momentum in coincidence with a reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred if we assume that the proton was a spectator to the reaction. This method, known as spectator tagging, was used to study the electron scattering from high-momentum neutrons in deuterium. The data were taken with a 5.765 GeV polarized electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CLAS detector. The accumulated data cover a wide kinematic range, reaching values of the invariant mass of the unobserved final state W* up to 3 GeV. A data sample of approximately 5 - 10{sup 5} events, with protons detected at large scattering angles (as high as 136 degrees) in coincidence with the forward electrons, was selected. The product of the neutron structure function with the initial nucleon momentum distribution F{sub 2n}. S was extracted for different values of W*, backward proton momenta p{sub s} and momentum transfer Q{sup 2}. The data were compared to a calculation based on the spectator approximation and using the free nucleon form factors and structure functions. A strong enhancement in the data, not reproduced by the model, was observed at cos(theta{sub pq}) > -0.3 (where theta{sub pq} is the proton scattering angle relative to the direction of the momentum transfer) and can be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. The bound nucleon structure function F{sub 2n} was studied in the region cos(theta{sub pq}) < -0.3 as a function of W* and scaling variable x*. At high spectator proton momenta the struck neutron is far off its mass shell. At p{sub s

  13. The pion nucleon scattering lengths from pionic hydrogen and deuterium

    NASA Astrophysics Data System (ADS)

    Schröder, H.-Ch.; Badertscher, A.; Goudsmit, P. F. A.; Janousch, M.; Leisi, H. J.; Matsinos, E.; Sigg, D.; Zhao, Z. G.; Chatellard, D.; Egger, J.-P.; Gabathuler, K.; Hauser, P.; Simons, L. M.; Rusi El Hassani, A. J.

    2001-07-01

    This is the final publication of the ETH Zurich Neuchâtel PSI collaboration on the pionic hydrogen and deuterium precision X-ray experiments. We describe the recent hydrogen 3 p 1 s measurement, report on the determination of the Doppler effect correction to the transition line width, analyze the deuterium shift measurement and discuss implications of the combined hydrogen and deuterium results. From the pionic hydrogen 3 p 1 s transition experiments we obtain the strong-interaction energy level shift \\varepsilon_{1s} = -7.108±0.013 (stat.)±0.034 (syst.) eV and the total decay width Γ_{1s} = 0.868±0.040 (stat.)±0.038 (syst.) eV of the 1s state. Taking into account the electromagnetic corrections we find the hadronic π N s-wave scattering amplitude a_{π-prightarrowπ-p} = 0.0883±0.0008 m_{π}^{-1} for elastic scattering and a_{π-prightarrowπ0n} = -0.128±0.006 m_{π} ^{-1} for single charge exchange, respectively. We then combine the pionic hydrogen results with the 1 s level shift measurement on pionic deuterium and test isospin symmetry of the strong interaction: our data are still compatible with isospin symmetry. The isoscalar and isovector π N scattering lengths (within the framework of isospin symmetry) are found to be b_0 = -0.0001^{+0.0009}_{-0.0021} m_{π}^{-1} and b1 = -0.0885^{+0.0010}_{-0.0021} m_{π} ^{-1}, respectively. Using the GMO sum rule, we obtain from b_1 a new value of the π N coupling constant (g_{π N} = 13.21_{-0.05}^{+0.11}) from which follows the Goldberger Treiman discrepancy Δ_{{GT}} =0.027_{-0.008}^{+0.012}. The new values of b_0 and g_{π N} imply an increase of the nucleon sigma term by at least 9 MeV.

  14. The effects of deuterium on static posture control

    NASA Technical Reports Server (NTRS)

    Layne, Charles S.

    1990-01-01

    A significant operational problem impacting upon the Space Shuttle program involves the astronaut's ability to safely egress from the Orbiter during an emergency situation. Following space flight, astronauts display significant movement problems. One variable which may contribute to increased movement ataxia is deuterium (D2O). Deuterium is present in low levels within the Orbiter's water supply but may accumulate to significant physiological levels during lengthy missions. Deuterium was linked to a number of negative physiological responses, including motion sickness, decreased metabolism, and slowing of neural conduction velocity. The effects of D2O on static postural control in response to a range of dosage levels were investigated. Nine sugjects were divided into three groups of three subjects each. The groups were divided into a low, medium, and a high D2O dosage group. The subjects static posture was assessed with the use of the EquiTest systems, a commercially available postural control evaluation system featuring movable force plates and a visual surround that can be servoed to the subject's sway. In addition to the force plate information, data about the degree of subject sway about the hips and shoulders was obtained. Additionally, surface electromyographic (EMG) data from the selected lower limb muscles were collected along with saliva samples used to determine the amount of deuterium enrichment following D2O ingestion. Two baseline testing sessions were performed using the EquiTest testing protocol prior to ingestion of the D2O. Thirty minutes after dosing, subjects again performed the tests. Two more post-dosing tests were run with an interest interval of one hour. Preliminary data anlaysis indicates that only subjects in the igh dose group displayed any significant static postural problems. Future analyses of the sway and EMG is expected to reveal significant variations in the subject's postural control strategy following D2O dosing. While

  15. Diagnosing radiative shocks from deuterium and tritium implosions on NIFa)

    NASA Astrophysics Data System (ADS)

    Pak, A.; Divol, L.; Weber, S.; Döppner, T.; Kyrala, G. A.; Kilne, J.; Izumi, N.; Glenn, S.; Ma, T.; Town, R. P.; Bradley, D. K.; Glenzer, S. H.

    2012-10-01

    During the recent ignition tuning campaign at the National Ignition Facility, layered cryogenic deuterium and tritium capsules were imploded via x-ray driven ablation. The hardened gated x-ray imager diagnostic temporally and spatially resolves the x-ray emission from the core of the capsule implosion at energies above ˜8 keV. On multiple implosions, ˜200-400 ps after peak compression a spherically expanding radiative shock has been observed. This paper describes the methods used to characterize the radial profile and rate of expansion of the shock induced x-ray emission.

  16. DIY Fraction Pack.

    ERIC Educational Resources Information Center

    Graham, Alan; Graham, Louise

    2003-01-01

    Describes a very successful attempt to teach fractions to year 5 pupils based on pupils making their own fraction pack. Children decided for themselves how to make the fractional slices used in the activity using colored cardboard sheets and templates of a paper circle consisting of 24 equal slices. (Author/NB)

  17. Measurements of Time-Dependent CP-Asymmetry Parameters in B Meson Decays to η' K0 and of Branching Fractions of SU(3) Related Modes with BaBar Experiment at SLAC

    SciTech Connect

    Biassoni, Pietro

    2009-01-01

    In this thesis work we have measured the following upper limits at 90% of confidence level, for B meson decays (in units of 10-6), using a statistics of 465.0 x 106 B$\\bar{B}$ pairs: β(B0 → ηK0) < 1.6 β(B0 → ηη) < 1.4 β(B0 → η'η') < 2.1 β(B0 → ηΦ) < 0.52 β(B0 → ηω) < 1.6 β(B0 → η'Φ) < 1.2 β(B0 → η'ω) < 1.7 We have no observation of any decay mode, statistical significance for our measurements is in the range 1.3-3.5 standard deviation. We have a 3.5σ evidence for B → ηω and a 3.1 σ evidence for B → η'ω. The absence of observation of the B0 → ηK0 open an issue related to the large difference compared to the charged mode B+ → ηK+ branching fraction, which is measured to be 3.7 ± 0.4 ± 0.1 [118]. Our results represent substantial improvements of the previous ones [109, 110, 111] and are consistent with theoretical predictions. All these results were presented at Flavor Physics and CP Violation (FPCP) 2008 Conference, that took place in Taipei, Taiwan. They will be soon included into a paper to be submitted to Physical Review D. For time-dependent analysis, we have reconstructed 1820 ± 48 flavor-tagged B0 → η'K0 events, using the final BABAR statistic of 467.4 x 106 B$\\bar{B}$ pairs. We use these events to measure the time-dependent asymmetry parameters S and C. We find S = 0.59 ± 0.08 ± 0.02, and C = -0.06 ± 0.06 ± 0.02. A non-zero value of C would represent a directly CP non-conserving component in B0 → η'K0, while S would be equal to sin2β measured in B0 → J/ΨKs0 [108], a mixing-decay interference effect, provided the decay is dominated by amplitudes of a single weak phase. The new measured value of S can be considered in agreement with the expectations of the

  18. Pyrolysis compound specific isotopic analysis (δ13C and δD Py-CSIA) of soil organic matter size fractions under four vegetation covers.

    NASA Astrophysics Data System (ADS)

    Jiménez-Morillo, Nicasio T.; González-Vila, Francisco J.; Almendros, Gonzalo; De la Rosa, José M.; González-Pérez, José A.

    2015-04-01

    specific SOM compounds released directly from pyrolysis (Py-CSIA); lipids (Alkenes), aromatic unspecific (alkylphenols), lignin (methoxyphenols) and polysaccharides (anhydrosugars) derived molecules. For all coarse fractions the δ13C and δD values had the same general behavior with sugar derived molecules being enriched in the heavy isotope. Regarding alkenes δ13C isotopic signature, this was variable and dependent upon the main cover vegetation that may reflect different fractionations at different synthesis stages (Chikaraishi & Naraoka, 2001), The δD values for specific compounds had a similar behavior to that for δ13C, being the sugar derived compounds the most deuterium enriched in comparison with lipid and lignin derived pyrolysis products. A conspicuous δD fractionation was observed for the sugar derived compounds in the fine fractions as compared with the coarse ones, with a depletion in deuterium, mainly for the PA sample where the depletion was the highest (c. -140 ‰). This may points to the occurrence of biological reworking with a higher microbiological activity fixing the lighter isotope in the soil fine organic fractions. It is known that lipid hydrogen is deuterium depleted relative to bulk organic hydrogen (Smith and Epstein, 1970). In line with this, in our study the lipid derived compounds had the largest deuterium depleted signature with a difference between bulk and lipid δD values was c. -35‰. This fractionation was highest in Pine (PP) and Rockrose (HH). The combination of traditional techniques for the study of SOM i.e. Py-GC/MS and IRMS, with new hyphenated analytical pyrolysis techniques i.e. Py-CSIA opens new possibilities and windows of information in SOM research. Our findings points to the occurrence of more or less complex processes that affects SOM chemical characteristics; whereas the coarse fraction resembles the chemical structure of the above vegetation, this SOM "memory" is less defined in the fine fractions, probably due to

  19. Peptide-Column Interactions and Their Influence on Back Exchange Rates in Hydrogen/Deuterium Exchange-MS

    NASA Astrophysics Data System (ADS)

    Sheff, Joey G.; Rey, Martial; Schriemer, David C.

    2013-07-01

    Hydrogen/deuterium exchange (HDX) methods generate useful information on protein structure and dynamics, ideally at the individual residue level. Most MS-based HDX methods involve a rapid proteolytic digestion followed by LC/MS analysis, with exchange kinetics monitored at the peptide level. Localizing specific sites of HDX is usually restricted to a resolution the size of the host peptide because gas-phase processes can scramble deuterium throughout the peptide. Subtractive methods may improve resolution, where deuterium levels of overlapping and nested peptides are used in a subtractive manner to localize exchange to smaller segments. In this study, we explore the underlying assumption of the subtractive method, namely, that the measured back exchange kinetics of a given residue is independent of its host peptide. Using a series of deuterated peptides, we show that secondary structure can be partially retained under quenched conditions, and that interactions between peptides and reversed-phase LC columns may both accelerate and decelerate residue HDX, depending upon peptide sequence and length. Secondary structure is induced through column interactions in peptides with a solution-phase propensity for structure, which has the effect of slowing HDX rates relative to predicted random coil values. Conversely, column interactions can orient random-coil peptide conformers to accelerate HDX, the degree to which correlates with peptide charge in solution, and which can be reversed by using stronger ion pairing reagents. The dependency of these effects on sequence and length suggest that subtractive methods for improving structural resolution in HDX-MS will not offer a straightforward solution for increasing exchange site resolution.

  20. [Microbial synthesis of deuterium labelled L-phenylalanine with different levels of isotopic enrichment by facultative methylotrophic bacterium Brevibacterium methylicum with RMP assimilation of carbon].

    PubMed

    Mosin, O V; Shvets, V I; Skladnev, D A; Ignatov, I

    2014-01-01

    The preparative microbial synthesis of amino acids labelled with stable isotopes, including deuterium ( 2 H), suitable for biomedical applications by methylotrophic bacteria was studied using L-phenylalanine as example. This amino acid is secreted by Gram-negative aerobic facultative methylotrophic bacteria Brevibacterium methylicum, assimilating methanol via ribulose-5-monophosphate (RMP) cycle of assimilation of carbon, The data on adaptation of L-phenylalanine secreted by methylotrophic bacterium В. methylicum to the maximal concentration of deuterium in the growth medium with 98% 2 Н 2 O and 2% [ 2 Н]methanol, and biosynthesis of deuterium labelled L-phenylalanine With different levels of enrichment are presented. The strain was adapted by means of plating initial cells on firm (2% agarose) minimal growth media with an increasing gradient of 2 Н 2 O concentration from 0; 24.5; 49.0; 73.5 up to 98% 2 Н 2 O followed by subsequent selection of separate colonies stable to the action of 2 Н 2 O. These colonies were capable to produce L-phenylalanine. L-phenylalanine was extracted from growth medium by extraction with isopropanol with the subsequent crystallization in ethanol (output 0.65 g/l). The developed method of microbial synthesis allows to obtain deuterium labelled L-phenylalanine with different levels of isotopic enrichment, depending on concentration of 2 Н 2 O in growth media, from 17% (on growth medium with 24,5% 2 Н 2 O) up to 75% (on growth medium with 98% 2 Н 2 O) of deuterium in the molecule that is confirmed with the data of the electron impact (EI) mass- spectrometry analysis of methyl ethers of N-dimethylamino(naphthalene)-5-sulfochloride (dansyl) phenylalanine in these experimental conditions. PMID:25249528