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Sample records for deuterium depleted water

  1. Effect of deuterium-depleted water on selected cardiometabolic parameters in fructose-treated rats.

    PubMed

    Rehakova, R; Klimentova, J; Cebova, M; Barta, A; Matuskova, Z; Labas, P; Pechanova, O

    2016-10-24

    Deuterium-depleted water (DDW) has a lower concentration of deuterium than occurs naturally (less than 145 ppm). While effects of DDW on cancer started to be intensively studied, the effects on cardiovascular system are completely unknown. Thus, we aimed to analyze the effects of DDW (55+/-5 ppm) administration to 12-week-old normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) treated with 15 % fructose for 6 weeks. Blood pressure (BP) and selected biochemical parameters were measured together with determination of nitric oxide synthase (NOS) activity and iNOS and eNOS protein expressions in the left ventricle (LV) and aorta. Neither DDW nor fructose had any significant effect on BP in both strains. DDW treatment decreased total cholesterol and triglyceride levels in WKY, but it was not able to prevent increase in the same parameters elevated due to fructose treatment in SHR. Both fructose and DDW increased insulin level in WKY. Fructose did not affect NOS activity either in WKY or SHR. DDW increased NOS activity in LV of both WKY and SHR, while it decreased NOS activity and iNOS expression in the aorta of SHR with or without fructose treatment. In conclusion, DDW treatment significantly modified biochemical parameters in WKY together with NOS activity elevation in the heart. On the other hand, it did not affect biochemical parameters in SHR, but decreased NOS activity elevated due to iNOS upregulation in the aorta.

  2. Submolecular regulation of cell transformation by deuterium depleting water exchange reactions in the tricarboxylic acid substrate cycle.

    PubMed

    Boros, László G; D'Agostino, Dominic P; Katz, Howard E; Roth, Justine P; Meuillet, Emmanuelle J; Somlyai, Gábor

    2016-02-01

    The naturally occurring isotope of hydrogen ((1)H), deuterium ((2)H), could have an important biological role. Deuterium depleted water delays tumor progression in mice, dogs, cats and humans. Hydratase enzymes of the tricarboxylic acid (TCA) cycle control cell growth and deplete deuterium from redox cofactors, fatty acids and DNA, which undergo hydride ion and hydrogen atom transfer reactions. A model is proposed that emphasizes the terminal complex of mitochondrial electron transport chain reducing molecular oxygen to deuterium depleted water (DDW); this affects gluconeogenesis as well as fatty acid oxidation. In the former, the DDW is thought to diminish the deuteration of sugar-phosphates in the DNA backbone, helping to preserve stability of hydrogen bond networks, possibly protecting against aneuploidy and resisting strand breaks, occurring upon exposure to radiation and certain anticancer chemotherapeutics. DDW is proposed here to link cancer prevention and treatment using natural ketogenic diets, low deuterium drinking water, as well as DDW production as the mitochondrial downstream mechanism of targeted anti-cancer drugs such as Avastin and Glivec. The role of (2)H in biology is a potential missing link to the elusive cancer puzzle seemingly correlated with cancer epidemiology in western populations as a result of excessive (2)H loading from processed carbohydrate intake in place of natural fat consumption. Published by Elsevier Ltd.

  3. [Influence of deuterium depleted water on freeze-dried tissue isotopic composition and morphofunctional body performance in rats of different generations].

    PubMed

    Dzhimak, S S; Baryshev, M G; Basov, A A; Timakov, A A

    2014-01-01

    The influence of deuterium depleted water on the body of different rats generations was investigated in physiological conditions. As a result of this study it was established that the most significant and rapid reduction in D/H equilibrium was observed in plasma (by 36.2%), and lyophilized kidney tissues (by 15.8%). Less pronounced deuterium decrease was characteristic of liver tissue (9.3%) and heart (8.5%). Stabilization of the isotopic exchange reaction rate was fixed in the blood and tissues of rats, starting from the second generation. At the same time when deuterium depleted water (40 ppm) was used in dietary intake, the change in morphological and functional parameters in laboratory animals associated with the processes of adaptation to the effects of substress isotopic D/H gradient was also noted. The study shows that modification of:only drinking water intake regime can't significantly change the deuterium content in tissues of metabolically active organs, because of the concurrent deuterium receipt in food substances of plant and animal origin.

  4. Water Depletion Threatens Agriculture

    NASA Astrophysics Data System (ADS)

    Brauman, K. A.; Richter, B. D.; Postel, S.; Floerke, M.; Malsy, M.

    2014-12-01

    Irrigated agriculture is the human activity that has by far the largest impact on water, constituting 85% of global water consumption and 67% of global water withdrawals. Much of this water use occurs in places where water depletion, the ratio of water consumption to water availability, exceeds 75% for at least one month of the year. Although only 17% of global watershed area experiences depletion at this level or more, nearly 30% of total cropland and 60% of irrigated cropland are found in these depleted watersheds. Staple crops are particularly at risk, with 75% of global irrigated wheat production and 65% of irrigated maize production found in watersheds that are at least seasonally depleted. Of importance to textile production, 75% of cotton production occurs in the same watersheds. For crop production in depleted watersheds, we find that one half to two-thirds of production occurs in watersheds that have not just seasonal but annual water shortages, suggesting that re-distributing water supply over the course of the year cannot be an effective solution to shortage. We explore the degree to which irrigated production in depleted watersheds reflects limitations in supply, a byproduct of the need for irrigation in perennially or seasonally dry landscapes, and identify heavy irrigation consumption that leads to watershed depletion in more humid climates. For watersheds that are not depleted, we evaluate the potential impact of an increase in irrigated production. Finally, we evaluate the benefits of irrigated agriculture in depleted and non-depleted watersheds, quantifying the fraction of irrigated production going to food production, animal feed, and biofuels.

  5. Deuterium content of water increases depression susceptibility: the potential role of a serotonin-related mechanism.

    PubMed

    Strekalova, Tatyana; Evans, Matthew; Chernopiatko, Anton; Couch, Yvonne; Costa-Nunes, João; Cespuglio, Raymond; Chesson, Lesley; Vignisse, Julie; Steinbusch, Harry W; Anthony, Daniel C; Pomytkin, Igor; Lesch, Klaus-Peter

    2015-01-15

    Environmental factors can significantly affect disease prevalence, including neuropsychiatric disorders such as depression. The ratio of deuterium to protium in water shows substantial geographical variation, which could affect disease susceptibility. Thus the link between deuterium content of water and depression was investigated, both epidemiologically, and in a mouse model of chronic mild stress. We performed a correlation analysis between deuterium content of tap water and rates of depression in regions of the USA. Next, we used a 10-day chronic stress paradigm to test whether 2-week deuterium-depleted water treatment (91 ppm) affects depressive-like behavior and hippocampal SERT. The effect of deuterium-depletion on sleep electrophysiology was also evaluated in naïve mice. There was a geographic correlation between a content of deuterium and the prevalence of depression across the USA. In the chronic stress model, depressive-like features were reduced in mice fed with deuterium-depleted water, and SERT expression was decreased in mice treated with deuterium-treated water compared with regular water. Five days of predator stress also suppressed proliferation in the dentate gyrus; this effect was attenuated in mice fed with deuterium-depleted water. Finally, in naïve mice, deuterium-depleted water treatment increased EEG indices of wakefulness, and decreased duration of REM sleep, phenomena that have been shown to result from the administration of selective serotonin reuptake inhibitors (SSRI). Our data suggest that the deuterium content of water may influence the incidence of affective disorder-related pathophysiology and major depression, which might be mediated by the serotoninergic mechanisms. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  6. Deuterium-rich Water in Meteorites

    NASA Astrophysics Data System (ADS)

    Deloule, E.; Robert, F.

    1995-09-01

    D/H ratios of 2 meteorites (Renazzo CR and Semarkona LL3), which are known to exhibit the largest departures from the terrestrial hydrogen isotopic ratios, have been determined with the CRPG Nancy ion-microprobe. Correlations between the D/H ratios and the chemical compositions (H2O, K, Si, C/H) of plausible hydrogen carriers were observed. From these correlations, it is possible to show that, contrary to previous interpretations, phyllosilicates are the carriers of the deuterium-rich hydrogen in Semarkona and Renazzo : 870 x10-6 D/H 670 x106 (+4600 dD 3300) and 320 x10-6 (dD 1050), respectively. Hydrogen is also present in the chondrules of these two deuterium-rich meteorites. Isotopic equilibrium between the deuterium depleted phases and the deuterium-rich phyllosilicates was never attained. This is illustrated at a micron scale by the D/H ratios obtained continuously during a 3 hours measurement on a same position (see figure below). It can be seen that water-rich mineral(s) having D/H up to 550 x10-6 (dD = +2500) are in contact with a mineral having D/H = 234 x10-6 (dD = +500). The thickness of the boundary where the diffusion of hydrogen took place is restricted to less than 0.2 mm. Such isotopic heterogeneity is quite spectacular if one remembers that the isotopic variations that we can see within these 0.2 mm are an order of magnitude larger than the total observed variations on Earth. The large differences in D/H ratios between matrix (up to 700 x 10-6, dD up to +3500) and chondrules (from 120 x10-6 (dD = -230) to 230 x10-6 (dD = +475)) show that hydrogen in chondrules cannot originate from the matrix by simple contamination or diffusion processes. The high D/H ratios measured in water bearing minerals could not have been produced thermally within a dense solar nebula. Chemical reactions (i.e. involving ions or radicals), taking place in interstellar space or in the outer regions of the nebula at 110-140K are presently the only conceivable mechanisms

  7. 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.

  8. Advantages of isotopic depletion of proteins for hydrogen/deuterium exchange experiments monitored by mass spectrometry.

    PubMed

    Bou-Assaf, George M; Chamoun, Jean E; Emmett, Mark R; Fajer, Piotr G; Marshall, Alan G

    2010-04-15

    Solution-phase hydrogen/deuterium exchange (HDX) monitored by mass spectrometry is an excellent tool to study protein-protein interactions and conformational changes in biological systems, especially when traditional methods such as X-ray crystallography or nuclear magnetic resonance are not feasible. Peak overlap among the dozens of proteolytic fragments (including those from autolysis of the protease) can be severe, due to high protein molecular weight(s) and the broad isotopic distributions due to multiple deuterations of many peptides. In addition, different subunits of a protein complex can yield isomeric proteolytic fragments. Here, we show that depletion of (13)C and/or (15)N for one or more protein subunits of a complex can greatly simplify the mass spectra, increase the signal-to-noise ratio of the depleted fragment ions, and remove ambiguity in assignment of the m/z values to the correct isomeric peptides. Specifically, it becomes possible to monitor the exchange progress for two isobaric fragments originating from two or more different subunits within the complex, without having to resort to tandem mass spectrometry techniques that can lead to deuterium scrambling in the gas phase. Finally, because the isotopic distribution for a small to medium-size peptide is essentially just the monoisotopic species ((12)C(c)(1)H(h)(14)N(n)(16)O(o)(32)S(s)), it is not necessary to deconvolve the natural abundance distribution for each partially deuterated peptide during HDX data reduction.

  9. 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.

  10. 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.

  11. 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.

  12. Water drives the deuterium content of the methane emitted from plants

    NASA Astrophysics Data System (ADS)

    Vigano, I.; Holzinger, R.; Keppler, F.; Greule, M.; Brand, W. A.; Geilmann, H.; van Weelden, H.; Röckmann, T.

    2010-07-01

    The spatial distribution of the deuterium content of precipitation has a well-established latitudinal variation that is reflected in organic molecules in plants growing at different locations. Some laboratory and field studies have already shown that the deuterium content of methane emitted from methanogens can be partially related to δD variations of the water in the surrounding environment. Here we present a similar relation for the methane emitted from plant biomass under UV radiation. To show this relation, we determined the hydrogen isotopic composition of methane released from leaves of a range of plants grown with water of different deuterium content (δD = -130‰ to +115‰). The plant leaves were irradiated with UV light and the CH 4 isotopic composition was measured by continuous flow isotope ratio mass spectrometry (CF-IRMS). Furthermore, the deuterium content of bulk biomass and of the methoxyl (OCH 3) groups of the biomass was measured. The D/H ratio successively decreases from bulk biomass (δD = -106‰ to -50‰) via methoxyl groups (δD = -310‰ to -115‰) to the CH 4 emitted (δD = -581‰ to -196‰). The range of isotope ratios in bulk biomass and OCH 3 groups is smaller than in the water used to grow the plants. Methoxyl groups, which contain only non-exchangeable hydrogen, can be used to assess the fraction of external water that was incorporated before OCH 3 groups were formed. Surprisingly, the CH 4 formed under UV irradiation has a wider isotopic range than the OCH 3 groups. Although the precise production pathway cannot be fully determined, the presented experiments indicate that methoxyl groups are not the only source substrate for CH 4, but that other sources, including very depleted ones, must contribute. The main limitation to the interpretation of the data is the possible influence of exchangeable water, which could not be quantified. Future studies should include measurements of leaf water and avoid interaction between different

  13. 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.

  14. Water Behavior in Bacterial Spores by Deuterium NMR Spectroscopy

    PubMed Central

    2015-01-01

    Dormant bacterial spores are able to survive long periods of time without nutrients, withstand harsh environmental conditions, and germinate into metabolically active bacteria when conditions are favorable. Numerous factors influence this hardiness, including the spore structure and the presence of compounds to protect DNA from damage. It is known that the water content of the spore core plays a role in resistance to degradation, but the exact state of water inside the core is a subject of discussion. Two main theories present themselves: either the water in the spore core is mostly immobile and the core and its components are in a glassy state, or the core is a gel with mobile water around components which themselves have limited mobility. Using deuterium solid-state NMR experiments, we examine the nature of the water in the spore core. Our data show the presence of unbound water, bound water, and deuterated biomolecules that also contain labile deuterons. Deuterium–hydrogen exchange experiments show that most of these deuterons are inaccessible by external water. We believe that these unreachable deuterons are in a chemical bonding state that prevents exchange. Variable-temperature NMR results suggest that the spore core is more rigid than would be expected for a gel-like state. However, our rigid core interpretation may only apply to dried spores whereas a gel core may exist in aqueous suspension. Nonetheless, the gel core, if present, is inaccessible to external water. PMID:24950158

  15. [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.

  16. Deuterium used as artificial tracer in column studies under saturated water flow conditions

    NASA Astrophysics Data System (ADS)

    Koeniger, P.; Geiges, M.; Leibundgut, Ch.

    2003-04-01

    In contrast to numerous investigations using deuterium as an environmental tracer, hydrological investigations with deuterium-labelled water are rather rare. Currently applications in groundwater studies are restricted due to increasing costs of spiking large water quantities but an application as intelligent tracer might be of advantage especially in combination with other tracers and under distinct environmental conditions. Therefore deuterium was applied as artificial tracer in column experiments that are well proved as a tool to characterise tracer behaviour in recent studies. Deuterium was tested in comparison to the more familiar conservative tracer fluorescein. Varying experimental conditions, e.g. column length (0.5, 1.0, 1.5 m), initial tracer concentration (0.01, 0.02, 0.2 mg) and flow velocity (1.5 to 6.0 m/d) were used to investigate tracer behaviour under saturated water flow conditions. Deuterium was analysed using an H/Device with chrome reduction connected to an isotope ratio mass spectrometer and expressed in relative concentrations [per mill V-SMOW]. Theoretical tracer breakthrough curves were calculated using a one dimensional dispersion model. The results indicate higher mean transport velocities and smaller dispersion for deuterium in all experiments. Due to different molecule properties that also determine the interaction of soil substrate and tracer, deuterium indicates a more conservative transport behaviour. Deuterium is non-toxic, completely soluble, chemically and biologically stable and not subject to light-influenced decay. Furthermore, it shows promise for investigations of water flow in the unsaturated zone, and of interactions of water in soil-plant-atmosphere systems. A further discussion of problems, together with possibilities for applying deuterium as an artificial tracer, will be presented.

  17. Water use patterns of three species in subalpine forest, Southwest China: the deuterium isotope approach

    Treesearch

    Qing Xu; Harbin Li; Jiquan Chen; Jiquan Cheng; Xiaoli Cheng; Shirong Liu; Shuqing An

    2011-01-01

    Determination of water sources of plant species in a community is critical for understanding the hydrological processes and their importance in ecosystem functions. Such partitioning of plant xylem water into specific sources (i.e. precipitation, groundwater) can be achieved by analyzing deuterium isotopic composition (δD) values for source waters. A subalpine dark...

  18. Deuterium-labeled phylloquinone fed to α-tocopherol-injected rats demonstrates sensitivity of low phylloquinone-containing tissues to menaquinone-4 depletion.

    PubMed

    Farley, Sherry M; Leonard, Scott W; Stevens, Jan F; Traber, Maret G

    2014-08-01

    The influence of excess α-tocopherol (α-T) on tissue depletion of phylloquinone (PK) and menaquinone-4 (MK-4) was evaluated. Rats (n = 5 per group) were fed deuterium-labeled PK (2 μmol/kg diet) for 17 days, thereby labeling the conversion from deuterium-labeled PK to d₄-MK-4. Then they were injected subcutaneously daily for the last 7 days with saline, vehicle, or α-T (100 mg/kg body weight). α-T injections (i) increased α-T concentrations by tenfold in liver, doubled them in plasma and most tissues, but they were unchanged in brain; (ii) increased the α-T metabolite, carboxyethyl hydroxychromanol (α-CEHC) concentrations: >25-fold in liver and kidney, tenfold in plasma and lung, and 50-fold in heart; brain contained detectable α-CEHC (0.26 ± 0.03 nmol/g) only in α-T-injected animals; and (iii) depleted most tissues' vitamin K. Compared with vehicle-injected rats, brains from α-T rats contained half the total vitamin K (10.3 ± 0.5 versus 21 ± 2 pmol/g, p = 0.0002) and one-third the d₄-MK-4 (5.8 ± 0.5 versus 14.6 ± 1.7 pmol/g, p = 0.0002). Tissues with high PK concentrations (liver, 21-30 pmol/g and heart, 28-50 pmol/g) were resistant to K depletion. We propose that α-T-dependent vitamin K depletion is likely mediated at an intermediate step in MK-4 production; thus, tissues with high PK are unaffected. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Creatine Supplementation Increases Total Body Water in Soccer Players: a Deuterium Oxide Dilution Study.

    PubMed

    Deminice, R; Rosa, F T; Pfrimer, K; Ferrioli, E; Jordao, A A; Freitas, E

    2016-02-01

    This study aimed to evaluate changes in total body water (TBW) in soccer athletes using a deuterium oxide dilution method and bioelectrical impedance (BIA) formulas after 7 days of creatine supplementation. In a double-blind controlled manner, 13 healthy (under-20) soccer players were divided randomly in 2 supplementation groups: Placebo (Pla, n=6) and creatine supplementation (CR, n=7). Before and after the supplementation period (0.3 g/kg/d during 7 days), TBW was determined by deuterium oxide dilution and BIA methods. 7 days of creatine supplementation lead to a large increase in TBW (2.3±1.0 L) determined by deuterium oxide dilution, and a small but significant increase in total body weight (1.0±0.4 kg) in Cr group compared to Pla. The Pla group did not experience any significant changes in TBW or body weight. Although 5 of 6 BIA equations were sensitive to determine TBW changes induced by creatine supplementation, the Kushner et al. 16 method presented the best concordance levels when compared to deuterium dilution method. In conclusion, 7-days of creatine supplementation increased TBW determined by deuterium oxide dilution or BIA formulas. BIA can be useful to determine TBW changes promoted by creatine supplementation in soccer athletes, with special concern for formula choice. © Georg Thieme Verlag KG Stuttgart · New York.

  20. DYNAMIC DEUTERIUM ENRICHMENT IN COMETARY WATER VIA ELEY–RIDEAL REACTIONS

    SciTech Connect

    Yao, Yunxi; Giapis, Konstantinos P., E-mail: giapis@cheme.caltech.edu

    2017-01-20

    The deuterium-to-hydrogen ratio (D/H) in water found in the coma of Jupiter family comet (JFC) 67P/Churyumov–Gerasimenko was reported to be (5.3 ± 0.7) × 10{sup −4}, the highest among comets and three times the value for other JFCs with an ocean-like ratio. This discrepancy suggests the diverse origins of JFCs and clouds the issue of the origin of Earth’s oceanic water. Here we demonstrate that Eley–Rideal reactions between accelerated water ions and deuterated cometary surface analogs can lead to instantaneous deuterium enrichment in water scattered from the surface. The reaction proceeds with H{sub 2}O{sup +} abstracting adsorbed D atoms, formingmore » an excited H{sub 2}DO* state, which dissociates subsequently to produce energetic HDO. Hydronium ions are also produced readily by the abstraction of H atoms, consistent with H{sub 3}O{sup +} detection and abundance in various comets. Experiments with water isotopologs and kinematic analysis on deuterated platinum surfaces confirmed the dynamic abstraction mechanism. The instantaneous fractionation process is independent of the surface temperature and may operate on the surface of cometary nuclei or dust grains, composed of deuterium-rich silicates and carbonaceous chondrites. The requisite energetic water ions have been detected in the coma of 67P in two populations. This dynamic fractionation process may temporarily increase the water D/H ratio, especially as the comet gets closer to the Sun. The magnitude of the effect depends on the water ion energy-flux and the deuterium content of the exposed cometary surfaces.« less

  1. Possibility of deuterium free water using as antitumoral means with reference to conditions of Martian expedition

    NASA Astrophysics Data System (ADS)

    Sinyak, Y.; Turusov, V.; Grigroriev, A.; Yaridze, D.; Gaidadimov, V.; Antoshina, E.; Gorkova, T.; Truhanova, L.

    The interplanetary space flights, Martian program as an example, will take place under conditions of increasing radiation level on crew. The search of methods for a decrease of oncologic risk produced by irradiation of astronauts, is one of the major factors of a successful implementation of a flight program. One of such methods is a usage by crew of potable water with the reduced concentrations of a heavy stable isotope of hydrogen - deuterium, which can be obtained in the regenerative life support systems. The heavy water (D2O) has toxic properties, distorting biochemical reactions in the cell, inhibiting process of DNA replication. It can be presumed that the replacement of deuterium in the water for protium will result in normalization of cell metabolism, reparation will take place and this will lead to the inhibition of tumour development. In this study the water with a decreased by 65% of deuterium was used. Antitumour properties of D 2-free water were studied with transplantable Lewis lung carcinoma in BDF1 strain of mice. First results show that average time of appearance of the first nodules at the site of transplantation was 14 % longer in mice fed D 2-free water as compared to control. The tumour volume in the experimental group (decreased content of D2 ) was always lower than in the control. Statistically significant differences in the tumour volume were registered at the 13, 15, 23, 26 and 28 -th days after transplantation. Inhibition of tumour growth was equal to 100% and 51% at the 5 th and 15-th days after- transplantation respectively. Increase of life span in the experimental group was 10%. The results indicate that the use by astronauts of water with decreased content of deuterium may decrease the risk of oncological diseases under conditions of high radiation level in the flight to Mars.

  2. Evaluating groundwater depletion as computed by a global water model

    NASA Astrophysics Data System (ADS)

    Schuh, Carina; Doell, Petra; Mueller Schmied, Hannes; Portmann, Felix

    2013-04-01

    When groundwater abstraction occurs faster than its replenishment over a long time and in a large area, the result is an overexploitation or depletion of groundwater. The problem is aggravated in areas where a growing population relies on freshwater resources for an intensive irrigation agriculture that is meant to guarantee food security. Especially in semi-arid and arid regions, the dominant use for groundwater is irrigation, reaching more than 95% of total water use. Therefore, the hot spots for groundwater depletion are the world's major irrigation areas like the central United States, north-western India and north China. Groundwater depletion presents a major threat to securing agricultural productivity and domestic water supply in these parts of the world. Besides, the environmental consequences that accompany the abstraction of groundwater are severe. Within the scientific community there is a common understanding that high-quality data on globally existing groundwater resources are deficient. In order to allow a sustainable management of the world's available groundwater resources, especially in areas under current water stress, the quantification of groundwater depletion is of high importance. WaterGAP (Water - Global Assessment and Prognosis) is a global model of water availability and water use which can serve to estimate the impact of groundwater and surface water withdrawals on groundwater storage. The new WaterGAP version 2.2a was modified to allow for an improved analysis of groundwater storage changes in semi-arid and arid regions. Now, groundwater recharge from surface water bodies is simulated in semi-arid and arid areas. Estimation of net groundwater abstractions was modified with respect of irrigation water use efficiency for groundwater and return flow fractions. In addition, irrigation consumptive use has been set to 70% of optimal irrigation consumptive use, assuming deficit irrigation to prevail in these parts of the world. Based on time

  3. Deuterium-labeled Phylloquinone Fed to α-Tocopherol Injected Rats Demonstrates Sensitivity of Low Phylloquinone-Containing Tissues to Menaquinone-4 Depletion

    PubMed Central

    Farley, Sherry M.; Leonard, Scott W.; Stevens, Jan F.; Traber, Maret G.

    2014-01-01

    The influence of excess α-tocopherol (α-T) on tissue depletion of phylloquinone (PK) and menaquinone-4 (MK-4) was evaluated by feeding rats (n=5/group) deuterium-labeled-PK (d4-PK, 2 µmol/kg) for 17 d, thereby labeling the conversion from d4-PK to d4-MK-4. Then they were injected subcutaneously daily for the last seven days with saline, vehicle, or α-T (100 mg/kg BW). α-T injections 1) increased α-T concentrations by 10-fold in liver, doubled them in plasma and most tissues, but they were unchanged in brain; 2) increased the α-T metabolite, carboxyethyl hydroxychromanol (α-CEHC) concentrations: >25-fold in liver and kidney, 10-fold in plasma and lung, and 50-fold in heart; brain contained detectable α-CEHC (0.26 ± 0.03 nmol/g) only in α-T injected animals and 3) depleted most tissues’ vitamin K. Compared with vehicle-injected rats, brains from α-T rats contained half the total vitamin K (10.3 ± 0.5 vs. 21 ± 2 pmol/g, P=0.0002) and one third the d4-MK-4 (5.8 ± 0.5 vs. 14.6 ± 1.7 pmol/g, P=0.0002). Tissues with high PK concentrations (liver, 21–30 pmol/g and heart, 28–50 pmol/g) were resistant to K depletion. We propose that α-T dependent vitamin K depletion is likely mediated at an intermediate step in MK-4 production; thus, tissues with high PK are unaffected. PMID:25044667

  4. Airborne Observations of Water Vapor Deuterium Excess in the Mid-Latitude Lower Troposphere

    NASA Astrophysics Data System (ADS)

    Salmon, O. E.; Welp, L.; Shepson, P. B.; Stirm, B. H.

    2017-12-01

    Water vapor is responsible for over half of the natural atmospheric greenhouse effect. As global temperatures increase due to fossil fuel combustion, atmospheric water vapor concentrations are also expected to increase in positive feedback. Additionally, studies have shown that urban areas can influence humidity levels, and the frequency and intensity of precipitation events. It is thus important to understand anthropogenic modification of the hydrological cycle, particularly around urban areas, where over half of the world's population resides. Airborne measurements of water vapor isotopologues containing 2H and 18O were conducted to better understand processes influencing atmospheric moisture levels around urban areas. Airborne measurements were conducted around the Indianapolis and Washington, D.C.-Baltimore areas during afternoon hours in February and March 2016, using a Los Gatos Research Water Vapor Isotope Analyzer installed in Purdue University's experimental aircraft, the Airborne Laboratory for Atmospheric Research. The measurements of 2H and 18O allow for the calculation of deuterium excess (= δ2H - 8*δ18O), which provides information about non-equilibrium processes, such as kinetic effects, air parcel mixing, and transpiration. There are few studies that have reported observations of deuterium excess above the surface level ( 100 m). During the measurement campaign, vertical profiles were frequently conducted from 300 m above the ground to an altitude of approximately 1.5 km, effectively characterizing water vapor isotope profiles spanning the boundary layer and lower free troposphere. Measurements probed the transition from planetary boundary layer air to free troposphere air to provide high resolution deuterium excess information across this interface. Processes such as Rayleigh distillation, atmospheric mixing, and surface fluxes potentially impacting water vapor deuterium excess through the boundary layer and free troposphere with be discussed.

  5. Depletion optimization of lumped burnable poisons in pressurized water reactors

    SciTech Connect

    Kodah, Z.H.

    1982-01-01

    Techniques were developed to construct a set of basic poison depletion curves which deplete in a monotonical manner. These curves were combined to match a required optimized depletion profile by utilizing either linear or non-linear programming methods. Three computer codes, LEOPARD, XSDRN, and EXTERMINATOR-2 were used in the analyses. A depletion routine was developed and incorporated into the XSDRN code to allow the depletion of fuel, fission products, and burnable poisons. The Three Mile Island Unit-1 reactor core was used in this work as a typical PWR core. Two fundamental burnable poison rod designs were studied. They are a solidmore » cylindrical poison rod and an annular cylindrical poison rod with water filling the central region.These two designs have either a uniform mixture of burnable poisons or lumped spheroids of burnable poisons in the poison region. Boron and gadolinium are the two burnable poisons which were investigated in this project. Thermal self-shielding factor calculations for solid and annular poison rods were conducted. Also expressions for overall thermal self-shielding factors for one or more than one size group of poison spheroids inside solid and annular poison rods were derived and studied. Poison spheroids deplete at a slower rate than the poison mixture because each spheroid exhibits some self-shielding effects of its own. The larger the spheroid, the higher the self-shielding effects due to the increase in poison concentration.« less

  6. 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.

  7. Modeling Insights into Deuterium Excess as an Indicator of Water Vapor Source Conditions

    NASA Technical Reports Server (NTRS)

    Lewis, Sophie C.; Legrande, Allegra Nicole; Kelley, Maxwell; Schmidt, Gavin A.

    2013-01-01

    Deuterium excess (d) is interpreted in conventional paleoclimate reconstructions as a tracer of oceanic source region conditions, such as temperature, where precipitation originates. Previous studies have adopted co-isotopic approaches to estimate past changes in both site and oceanic source temperatures for ice core sites using empirical relationships derived from conceptual distillation models, particularly Mixed Cloud Isotopic Models (MCIMs). However, the relationship between d and oceanic surface conditions remains unclear in past contexts. We investigate this climate-isotope relationship for sites in Greenland and Antarctica using multiple simulations of the water isotope-enabled Goddard Institute for Space Studies (GISS) ModelE-R general circulation model and apply a novel suite of model vapor source distribution (VSD) tracers to assess d as a proxy for source temperature variability under a range of climatic conditions. Simulated average source temperatures determined by the VSDs are compared to synthetic source temperature estimates calculated using MCIM equations linking d to source region conditions. We show that although deuterium excess is generally a faithful tracer of source temperatures as estimated by the MCIM approach, large discrepancies in the isotope-climate relationship occur around Greenland during the Last Glacial Maximum simulation, when precipitation seasonality and moisture source regions were notably different from present. This identified sensitivity in d as a source temperature proxy suggests that quantitative climate reconstructions from deuterium excess should be treated with caution for some sites when boundary conditions are significantly different from the present day. Also, the exclusion of the influence of humidity and other evaporative source changes in MCIM regressions may be a limitation of quantifying source temperature fluctuations from deuterium excess in some instances.

  8. Identifying water mass depletion in northern Iraq observed by GRACE

    NASA Astrophysics Data System (ADS)

    Mulder, G.; Olsthoorn, T. N.; Al-Manmi, D. A. M. A.; Schrama, E. J. O.; Smidt, E. H.

    2015-03-01

    Observations acquired by Gravity Recovery And Climate Experiment (GRACE) mission indicate a mass loss of 146 ± 6 mm equivalent water height (EWH) in northern Iraq between 2007 and 2009. These data are used as an independent validation of lake mass variations and a rainfall-runoff model, which is based on local geology and climate conditions. Model inputs are precipitation from Tropical Rainfall Measurement Mission (TRMM) observations, and climatic parameters from Global Land Data Assimilation Systems (GLDAS) model parameters. The model is calibrated with observed river discharge and includes a representation of the karstified aquifers in the region to improve model realism. Lake mass variations were derived from Moderate Resolution Imaging Spectroradiometer (MODIS) in combination with satellite altimetry and some in situ data. Our rainfall-runoff model confirms that northern Iraq suffered a drought between 2007 and 2009 and captures the annual cycle and longer trend of the observed GRACE data. The total mass depletion seen by GRACE between 2007 and 2009 is mainly explained by a lake mass depletion of 75 ± 3 mm EWH and a natural groundwater depletion of 39 ± 8 mm EWH. Our findings indicate that anthropogenic groundwater extraction has a minor influence in this region, while a decline in lake mass and natural depletion of groundwater play a key role.

  9. Spatial variation of deuterium enrichment in bulk water of snowgum leaves.

    PubMed

    Santrucek, Jirí; Kveton, Jirí; Setlík, Jirí; Bulícková, Lenka

    2007-01-01

    Deuterium enrichment of bulk water was measured and modeled in snowgum (Eucalyptus pauciflora Sieber ex Sprengel) leaves grown under contrasting air and soil humidity in arid and wet conditions in a glasshouse. A map of the enrichment was constructed with a resolution of 4 mm by using a newly designed cryodistillation method. There was progressively increasing enrichment in both longitudinal (along the leaf midrib) and transversal (perpendicular to the midrib) directions, most pronounced in the arid-grown leaf. The whole-leaf average of the enrichment was well below the value estimated by the Craig-Gordon model. The discrepancy between model and measurements persisted when the estimates were carried out separately for the leaf base and tip, which differed in temperature and stomatal conductance. The discrepancy was proportional to the transpiration rate, indicating the significance of diffusion-advection interplay (Péclet effect) of deuterium-containing water molecules in small veins close to the evaporating sites in the leaf. Combined Craig-Gordon and desert-river models, with or without the Péclet number, P, were used for predicting the leaf longitudinal enrichment. The predictions without P overestimated the measured values of deltadeuterium. Fixed P value partially improved the coincidence. We suggest that P should vary along the leaf length l to reconcile the modeled data with observations of longitudinal enrichment. Local values of P, P(l), integrating the upstream fraction of water used or the leaf area, substantially improved the model predictions.

  10. Conversion of deuterium gas to heavy water by catalytic isotopic exchange using wetproof catalyst

    SciTech Connect

    Quaiattini, R.J.; McGauley, M.P.; Burns, D.L.

    The invention at Chalk River Nuclear Laboratories of a simple method of wetproofing platinum catalysts allows them to retain their activity in liquid water. High performance catalysts for the hydrogen-water isotope exchange reaction that remain active for years can now be routinely produced. The first commercial application using the ordered-bed-type wetproofed isotope exchange catalyst developed and patented by Atomic Energy of Canada Ltd. has been successfully completed. Approximately 9100 m/sup 3/ of deuterium gas stored at Brookhaven National Laboratory was converted to high grade heavy water. Conversion efficiency exceeded 99.8%. The product D/sub 2/O concentration was 6.7 percentage points highermore » than the feed D/sub 2/ gas.« less

  11. Water-deuterium oxide exchange in polymers used in spacecraft applications. [outgassing from Mylar and Kapton

    NASA Technical Reports Server (NTRS)

    Carre, D. J.

    1980-01-01

    The replacement of water (H2O) by deuterium oxide (D2O) and the exchange between atmospheric water and adsorbed or absorbed D2O were investigated for the polymeric materials Kapton and Mylar using thermal gravimetric analysis and infrared spectroscopy. Replacement of H2O by D2O is easily accomplished. However, exposure of D2O samples to the ambient atmosphere or gases containing H2O results in rapid proton and deuteron exchange between H2O vapor and adsorbed D2O. Replacement of H2O by D2O would not be a practical solution to alleviate spectral interferences that would result from water outgassing in spacecraft orbital environments. Maintaining the materials of interest in a dehydrated state is a more reasonable approach.

  12. [Determination of deuterium concentration in foods and influence of water with modified isotopic composition on oxidation parameters and heavy hydrogen isotopes content in experimental animals].

    PubMed

    Basov, A A; Bykov, I M; Baryshev, M G; Dzhimak, S S; Bykov, M I

    2014-01-01

    The article presents the results of the study of the deuterium (D) content in food products as well as the influence of deuterium depleted water (DDW) on the concentration of heavy hydrogen isotopes in the blood and lyophilized tissues of rats. The most significant difference in the content of D was found between potato and pork fat, which indexes the standard delta notation (δ) D in promille, related to the international standard SMOW (Standard Mean Ocean of Water) amounted to -83,2 per thousand and -250,7 per thousand, respectively (p<0,05). Among the investigated samples of water deuterium concentration ranged from -75,5 per thousand (Narzan) to +72,1 per thousand (Kubai), that indicates the ability of some food products to increase the concentration of heavy hydrogen atoms in the body. The data obtained in the experimental modeling of the diet of male Wistar rats in the age of 5-6 mo (weight 235 ± 16 g) using DDW (δD = -743,2 per thousand) instead of drinking water (δD = -37,0 per thousand) with identical mineral composition showed that after 2 weeks significant (p <0,05) formation of isotopic (deuterium-protium, D/H) gradient in the body is possible. Changing the direction of isotopic D/H gradient in laboratory animals in comparison with its physiological indicators (72-127 per thousand, "plasma>tissue") is due to different rates ofisotopic exchange reactions in plasma and tissues (liver, kidney, heart), which can be explained by entering into the composition of a modified diet of organic substrates with more than DDW concentration D, which are involved in the construction of cellular structures and eventually lead to a redistribution of D and change direction of D/H gradient "plasma

  13. Soil Water Depletion After Four years of Forest Regrowth in SouthWestern Wisconsin

    Treesearch

    Richard S. Sartz; M. Dean Knighton

    1978-01-01

    The effect of cutting on water depletion from a 150-cm soil mantle does not appear to have diminished by the 7th year after the trees were cut. Mean seasonal depletion was 41, 64, and 146 mm for all vegetation removed, woody vegetation only removed, and uncut treatments, respectively. After 4 years of regrowth, the original bare and clearcut treatments depleted only...

  14. Deplete! Deplete! Deplete!

    NASA Astrophysics Data System (ADS)

    Woodson, J.

    2017-12-01

    Deplete is intended to demonstrate by analogy the harmful effect that Green House Gases (GHG's) such as CO2 and H2O vapor are causing to the Ozone Layer. Increasing temperatures from human activities are contributing to the depletion of Ozone.

  15. VERA Core Simulator methodology for pressurized water reactor cycle depletion

    DOE PAGES

    Kochunas, Brendan; Collins, Benjamin; Stimpson, Shane; ...

    2017-01-12

    This paper describes the methodology developed and implemented in the Virtual Environment for Reactor Applications Core Simulator (VERA-CS) to perform high-fidelity, pressurized water reactor (PWR), multicycle, core physics calculations. Depletion of the core with pin-resolved power and nuclide detail is a significant advance in the state of the art for reactor analysis, providing the level of detail necessary to address the problems of the U.S. Department of Energy Nuclear Reactor Simulation Hub, the Consortium for Advanced Simulation of Light Water Reactors (CASL). VERA-CS has three main components: the neutronics solver MPACT, the thermal-hydraulic (T-H) solver COBRA-TF (CTF), and the nuclidemore » transmutation solver ORIGEN. This paper focuses on MPACT and provides an overview of the resonance self-shielding methods, macroscopic-cross-section calculation, two-dimensional/one-dimensional (2-D/1-D) transport, nuclide depletion, T-H feedback, and other supporting methods representing a minimal set of the capabilities needed to simulate high-fidelity models of a commercial nuclear reactor. Results are presented from the simulation of a model of the first cycle of Watts Bar Unit 1. The simulation is within 16 parts per million boron (ppmB) reactivity for all state points compared to cycle measurements, with an average reactivity bias of <5 ppmB for the entire cycle. Comparisons to cycle 1 flux map data are also provided, and the average 2-D root-mean-square (rms) error during cycle 1 is 1.07%. To demonstrate the multicycle capability, a state point at beginning of cycle (BOC) 2 was also simulated and compared to plant data. The comparison of the cycle 2 BOC state has a reactivity difference of +3 ppmB from measurement, and the 2-D rms of the comparison in the flux maps is 1.77%. Lastly, these results provide confidence in VERA-CS’s capability to perform high-fidelity calculations for practical PWR reactor problems.« less

  16. Oxygen, deuterium, and strontium isotope characteristics of the Indus River water system

    NASA Astrophysics Data System (ADS)

    Sharma, Anupam; Kumar, Kamlesh; Laskar, Amzad; Singh, Sunil Kumar; Mehta, Pankaj

    2017-05-01

    Understanding the sources and compositional characteristics of waters and sediments in the Indus River system is extremely important as its water availability is one of the primary factors for sustenance of the irrigation activities and the socioeconomic status of a very densely populated region of the world. Here we used stable isotopic compositions (δD and δ18O) and strontium isotopic ratio (87Sr/86Sr) in the Indus River water, its tributaries and its small streams (nallahs) in the Indian territory to understand the regional hydrology, water sources, and catchment processes (evaporation, transpiration, recycling, and mixing). The δ18O values in the Indus River system (IRS) ranges from - 16.9‰ to - 12.5‰ and δD from - 122.8‰ to - 88.5‰. The Indus River and its major tributaries (such as the Zanskar, Nubra and Shyok rivers) are characterized by relatively lower δ18O values, whereas TangTse and other small streams contributing to the Indus are relatively enriched in 18O. The local meteoric water line for the IRS was found to be δD = 7.87 × δ18O + 11.41, which is similar to the Global Meteoric Water Line (GMWL) indicating meteoric origin of the water and insignificant secondary evaporation in the catchment. The Deuterium excess (d-excess) in the IRS varies between 6.5‰ and 14.9‰ with an average of 11.7‰, which is mostly higher than the long-term average for the Indian summer monsoon ( 8‰). The higher d-excess value is because of the contribution of moisture from westerlies; a simple mass balance shows 26% water in the main Indus channel is contributed by the westerlies originated from the Mediterranean Sea. The Sr isotope ratio in IRS varies between 0.70515 and 0.71291; wherein the Indus, and its tributary rivers Shyok and Nubra, are characterized by relatively high Sr isotope ratios (avg. 0.71086-0.71243) compared to the Zanskar and TangTse tributaries (Sr 0.709) because of the variation in silicate rock weathering component and carbonate

  17. Total body water measurements in adolescent athletes: a comparison of six field methods with deuterium dilution.

    PubMed

    Quiterio, Ana L; Silva, Analiza M; Minderico, Cláudia S; Carnero, Elvis A; Fields, David A; Sardinha, Luis B

    2009-07-01

    -Assessing hydration, that is, total body water (TBW) in adolescent athletes should be part of a comprehensive training program. However, there are no specific methods to assess TBW in young athletes. Moreover, the use of traditional techniques developed in healthy youths, based on a 2-compartment model, may yield inaccurate TBW estimates in young athletes. Therefore, the purpose of this study was to assess the accuracy of TBW non-reference field methods with a criterion method (i.e., deuterium dilution) in 118 adolescent athletes. Body volume was assessed by air displacement plethysmography, bone mineral was measured by dual-energy X-ray absorptiometry, and TBW by deuterium dilution. Non-reference TBW methods included 2 bioelectrical impedance analysis techniques (Tanita Body Composition Analyzer, model TBF-310) and bioelectrical impedance spectroscopy (BIS) (model 4000B); the Lohman's hydration constants of fat-free mass (FFM); and 3 derived anthropometric equations developed, respectively, by Kushner et al., Wells et al., and Morgenstern et al. The highest accuracy between TBW estimates and the reference model in both girls and boys was observed using the Lohman's constants (r2= 0.94, SEE = 1.56 kg; r2 = 0.92, SEE = 2.42 kg, respectively; p < 0.001), followed by both foot-to-foot Tanita (r2 = 0.88, SEE = 2.15 kg; r2 = 0.87, SEE = 3.01 kg, respectively; p < 0.001) and BIS (r2 = 0.92, SEE = 1.70 kg; r2 = 0.87, SEE = 3.04 kg, respectively; p < 0.001) with slopes and intercepts not significantly different from the line of identity. The regressions between anthropometric equations and the criterion method deviated from the line of identity (p < 0.05). The practical application of this study is that the specific constants of FFM hydration developed by Lohman seem to accurately estimate TBW in adolescent athletes. Foot-to-foot Tanita and BIS were also found to be valid and non-biased tools for predicting TBW. It would appear that the 3 anthropometric equations used are

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

    SciTech Connect

    Lee, J.

    1981-01-01

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

  19. 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

  20. Application of Gas Chromatography-Tandem Mass Spectrometry (GC/MS/MS) for the Analysis of Deuterium Enrichment of Water

    PubMed Central

    Walker, Dillon K.; Thaden, John J.; Deutz, Nicolaas E.P.

    2015-01-01

    Incorporation of deuterium from deuterium oxide (2H2O) into biological components is a commonly used approach in metabolic studies. Determining the dilution of deuterium in the body water pool (BW) can be used to estimate body composition. We describe three sensitive GC-MS/MS methods to measure water enrichment in BW . Samples were reacted with NaOH and U-13C3-acetone in an autosampler vial to promote deuterium exchange with U-13C3-acetone hydrogens. Headspace injections were made of U-13C3-acetone-saturated air onto a 30m DB-1MS column in EI-mode. Subjects ingested 30ml 2H2O and plasma samples were collected. BW was determined by standard equation. DXA scans were performed to calculate body mass, body volume and bone mineral content. A 4 compartmental model was used to estimate body composition (fat and fat free mass). Full scan experiments generated a m/z 45 peak and to a lesser extent a m/z 61 peak. Product fragment ions further monitored included 45 and 46 using selected ion monitoring (SIM;Method1), the 61>45 and 62>46 transition using multiple reaction monitoring (MRM;Method2) and the Neutral Loss, 62>45, transition (Method3). MRM methods were optimized for collision energy (CE) and collision-induced dissociation (CID) argon gas pressure with 6eV CE and 1.5 mTorr CID gas being optimal. Method2 was used for finally determination of 2H2O enrichment of subjects due to lower natural background. We have developed a sensitive method to determine 2H2O enrichment in body water to enable measurement of FM and FFM. PMID:26169138

  1. Private sector embedded water risk: Merging the corn supply chain network and regional watershed depletion

    NASA Astrophysics Data System (ADS)

    Kim, T.; Brauman, K. A.; Schmitt, J.; Goodkind, A. L.; Smith, T. M.

    2016-12-01

    Water scarcity in US corn farming regions is a significant risk consideration for the ethanol and meat production sectors, which comprise 80% of all US corn demand. Water supply risk can lead to effects across the supply chain, affecting annual corn yields. The purpose of our study is to assess the water risk to the US's most corn-intensive sectors and companies by linking watershed depletion estimates with corn production, linked to downstream companies through a corn transport model. We use a water depletion index as an improved metric for seasonal water scarcity and a corn sourcing supply chain model based on economic cost minimization. Water depletion was calculated as the fraction of renewable (ground and surface) water consumption, with estimates of more than 75% depletion on an annual average basis indicating a significant water risk. We estimated company water risk as the amount of embedded corn coming from three categories of water stressed counties. The ethanol sector had 3.1% of sourced corn grown from counties that were more than 75% depleted while the beef sector had 14.0%. From a firm perspective, Tyson, JBS, Cargill, the top three US corn demanding companies, had 4.5%, 9.6%, 12.8% of their sourced corn respectively, coming from watersheds that are more than 75% depleted. These numbers are significantly higher than the global average of 2.2% of watersheds being classified as more than 75% depleted. Our model enables corn using industries to evaluate their supply chain risk of water scarcity through modeling corn sourcing and watershed depletion, providing the private sector a new method for risk estimation. Our results suggest corn dependent industries are already linked to water scarcity risk in disproportionate amounts due to the spatial heterogeneity of corn sourcing and water scarcity.

  2. Depletion and capture: revisiting “The source of water derived from wells"

    USGS Publications Warehouse

    Konikow, Leonard F.; Leake, Stanley A.

    2014-01-01

    A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion and capture relative to groundwater withdrawals (extraction or pumpage) have not previously been well characterized. This study assesses the partitioning of long-term cumulative withdrawal volumes into fractions derived from storage depletion and capture, where capture includes both increases in recharge and decreases in discharge. Numerical simulation of a hypothetical groundwater basin is used to further illustrate some of Theis' (1940) principles, particularly when capture is constrained by insufficient available water. Most prior studies of depletion and capture have assumed that capture is unconstrained through boundary conditions that yield linear responses. Examination of real systems indicates that capture and depletion fractions are highly variable in time and space. For a large sample of long-developed groundwater systems, the depletion fraction averages about 0.15 and the capture fraction averages about 0.85 based on cumulative volumes. Higher depletion fractions tend to occur in more arid regions, but the variation is high and the correlation coefficient between average annual precipitation and depletion fraction for individual systems is only 0.40. Because 85% of long-term pumpage is derived from capture in these real systems, capture must be recognized as a critical factor in assessing water budgets, groundwater storage depletion, and sustainability of groundwater development. Most capture translates into streamflow depletion, so it can detrimentally impact ecosystems.

  3. Identifying water mass depletion in Northern Iraq observed by GRACE

    NASA Astrophysics Data System (ADS)

    Mulder, G.; Olsthoorn, T. N.; Al-Manmi, D. A. M. A.; Schrama, E. J. O.; Smidt, E. H.

    2014-10-01

    Observations acquired by Gravity Recovery And Climate Experiment (GRACE) mission indicate a mass loss of 31 ± 3 km3 or 130 ± 14 mm in Northern Iraq between 2007 and 2009. This data is used as an independent validation of a hydrologic model of the region including lake mass variations. We developed a rainfall-runoff model for five tributaries of the Tigris River, based on local geology and climate conditions. Model inputs are precipitation from Tropical Rainfall Measurement Mission (TRMM) observations, and potential evaporation from GLDAS model parameters. Our model includes a representation of the karstified aquifers that cause large natural groundwater variations in this region. Observed river discharges were used to calibrate our model. In order to get the total mass variations, we corrected for lake mass variations derived from Moderate Resolution Imaging Spectroradiometer (MODIS) in combination with satellite altimetry and some in-situ data. Our rainfall-runoff model confirms that Northern Iraq suffered a drought between 2007 and 2009 and is consistent with the mass loss observed by GRACE over that period. Also, GRACE observed the annual cycle predicted by the rainfall-runoff model. The total mass depletion seen by GRACE between 2007 and 2009 is mainly explained by a lake mass depletion of 74 ± 4 mm and a natural groundwater depletion of 37 ± 6 mm. Our findings indicate that man-made groundwater extraction has a minor influence in this region while depletion of lake mass and geology play a key role.

  4. Substituting freshwater: Can ocean desalination and water recycling capacities substitute for groundwater depletion in California?

    PubMed

    Badiuzzaman, Pierre; McLaughlin, Eoin; McCauley, Darren

    2017-12-01

    While the sustainability of resource depletion is a longstanding environmental concern, wider attention has recently been given to growing water scarcity and groundwater depletion. This study seeks to test the substitutability assumption embedded in weak sustainability indicators using a case study of Californian water supply. The volume of groundwater depletion is used as a proxy for unsustainable water consumption, and defined by synthesising existing research estimates into low, medium and high depletion baselines. These are compared against projected water supply increases from ocean desalination and water recycling by 2035, to determine whether new, drought-proof water sources can substitute for currently unsustainable groundwater consumption. Results show that the maximum projected supply of new water, 2.47 million acre-feet per year (MAF/yr), is sufficient to meet low depletion estimates of 2.02 MAF/yr, but fails to come near the high depletion estimate of 3.44 MAF/yr. This does not necessarily indicate physical limitations of substitutability, but more so socio-economic limitations influenced by high comparative costs. By including capacities in demand-substitutability via urban water conservation, maximum predicted capacities reach 5.57 MAF/yr, indicating wide room for substitution. Based on these results, investment in social and institutional capital is an important factor to enhance demand-side substitutability of water and other natural resources, which has been somewhat neglected by the literature on the substitutability of natural resources. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Developing the greatest Blue Economy: Water productivity, fresh water depletion, and virtual water trade in the Great Lakes basin

    NASA Astrophysics Data System (ADS)

    Mayer, A. S.; Ruddell, B. L.; Mubako, S. T.

    2016-12-01

    The Great Lakes basin hosts the world's most abundant surface fresh water reserve. Historically an industrial and natural resource powerhouse, the region has suffered economic stagnation in recent decades. Meanwhile, growing water resource scarcity around the world is creating pressure on water-intensive human activities. This situation creates the potential for the Great Lakes region to sustainably utilize its relative water wealth for economic benefit. We combine economic production and trade datasets with water consumption data and models of surface water depletion in the region. We find that, on average, the current economy does not create significant impacts on surface waters, but there is some risk that unregulated large water uses can create environmental flow impacts if they are developed in the wrong locations. Water uses drawing on deep groundwater or the Great Lakes themselves are unlikely to create a significant depletion, and discharge of groundwater withdrawals to surface waters offsets most surface water depletion. This relative abundance of surface water means that science-based management of large water uses to avoid accidentally creating "hotspots" is likely to be successful in avoiding future impacts, even if water use is significantly increased. Commercial water uses are the most productive, with thermoelectric, mining, and agricultural water uses in the lowest tier of water productivity. Surprisingly for such a water-abundant economy, the region is a net importer of water-derived goods and services. This, combined with the abundance of surface water, suggests that the region's water-based economy has room to grow in the 21st century.

  6. Identifying water mass depletion in Northern Iraq observed by GRACE

    NASA Astrophysics Data System (ADS)

    Mulder, Gert; Olsthoorn, Theo; Al-Manmi, Diary; Schrama, Ernst; Smidt, Ebel

    2014-05-01

    Observations acquired by Gravity Recovery And Climate Experiment (GRACE) mission indicates a mass loss of 31±3 km3 or 130±14 mm in Northern Iraq between 2006 and 2009. This data is used as an independent validation of a hydrologic model of the region including lake mass variations. We developed a rainfall-runoff model for five tributaries of the Tigris River, based on local geology and climate conditions. Model inputs are precipitation data from Tropical Rainfall Measurement Mission (TRMM) observations, and potential evaporation from GLDAS parameters. Our model includes an extensive network of karstified aquifers that causes large natural groundwater variations in this region. Observed river discharges have been used to calibrate our model. In order to get the total mass variations, we correct for lake mass variations derived from Moderate Resolution Imaging Spectroradiometer (MODIS) data in combination with satellite altimetry and some in-situ data. Our rainfall-runoff model confirms that Northern Iraq suffered a drought between 2006 and 2009 and is consistent with the mass loss observed by GRACE in that period. Also, GRACE picks up the annual cycle predicted by the rainfall-runoff model. The total mass depletion seen by GRACE between 2006 and 2009 is 130±14 mm, which is mainly explained by a lake mass depletion of 74±4 mm and a natural groundwater depletion of approximately 50 mm. Our findings indicate that man-made groundwater extraction has a minor influence in this region while depletion of lake mass and geology play a key role.

  7. Seasonal changes in background levels of deuterium and oxygen-18 prove water drinking by harp seals, which affects the use of the doubly labelled water method.

    PubMed

    Nordøy, Erling S; Lager, Anne R; Schots, Pauke C

    2017-12-01

    The aim of this study was to monitor seasonal changes in stable isotopes of pool freshwater and harp seal ( Phoca groenlandica ) body water, and to study whether these potential seasonal changes might bias results obtained using the doubly labelled water (DLW) method when measuring energy expenditure in animals with access to freshwater. Seasonal changes in the background levels of deuterium and oxygen-18 in the body water of four captive harp seals and in the freshwater pool in which they were kept were measured over a time period of 1 year. The seals were offered daily amounts of capelin and kept under a seasonal photoperiod of 69°N. Large seasonal variations of deuterium and oxygen-18 in the pool water were measured, and the isotope abundance in the body water showed similar seasonal changes to the pool water. This shows that the seals were continuously equilibrating with the surrounding water as a result of significant daily water drinking. Variations in background levels of deuterium and oxygen-18 in freshwater sources may be due to seasonal changes in physical processes such as precipitation and evaporation that cause fractionation of isotopes. Rapid and abrupt changes in the background levels of deuterium and oxygen-18 may complicate calculation of energy expenditure by use of the DLW method. It is therefore strongly recommended that analysis of seasonal changes in background levels of isotopes is performed before the DLW method is applied on (free-ranging) animals, and to use a control group in order to correct for changes in background levels. © 2017. Published by The Company of Biologists Ltd.

  8. THE BIOLOGY OF DEUTERIUM

    SciTech Connect

    Katz, J.J.; Crespi, H.L.; Finkel, A.J.

    1958-10-31

    g been noted, but the full scope and nature of these effects still remain largely unexplored. Early work was greatly hampered by the difficulties of obtaining deuterium but the development of a vast nuclear energy technology has made deuterium available on a larghe scale. It has now become opportune to undertake comprehensive reports work undertaken on algae, fungi, bacteria, and mammals. Mice will tolerate up to about 40 per cent D/sub 2/O in the drinking water for at least four months; of about 30 per cent heavy water. When deuteration is into various tissues and organs to the amount ofmore » from 40 to 50 per cent of the deuterium in the body fluids. 25 atom per cent, for as long as 12 months without obcal effects of deuterium is the kinetic isotpe effect. In general, bonds to deuterium react less readily than bonds to hydrogen; in consequence, reaction reates are decreased, and a depression in tissue metabolism should result. At concentrations about 30 atom per cen deuterium mice and rats show weakness, neutrmuscular por and death Since neoplastic cells metabolize rapidly, presumably these should be particularly sensitive to the effects of deuteration. Deuteration of host mice resulted in reduced growth rates of injected Krebs-2 ascites tumors and of inoculated P-1534 lymphatic leukemia. The general effects of deuterium on growth has been Chlorella vulgaris and Scenedesmus obliquus, have been have been harvested that yield water of combustion containing more than 90 atom per cent deuterium. The e were altered by deuteration. The fungi Penicillium notatum and Aspergillus fonsecaeus have been grown in media containing various concentrations of D/sub 2/O up to 99.6 per cent, and here, too, morphology, sporulation, pigment production, and growth rate were all affected by deuteration. The results obtained with algae clearly indicate the feasibility of producing fully deuterated compounds of biological significance by biosynthetic procedures. Bacterial studies on

  9. Ozone depletion - Ultraviolet radiation and phytoplankton biology in Antarctic waters

    NASA Technical Reports Server (NTRS)

    Smith, R. C.; Prezelin, B. B.; Baker, K. S.; Bidigare, R. R.; Boucher, N. P.; Coley, T.; Karentz, D.; Macintyre, S.; Matlick, H. A.; Menzies, D.

    1992-01-01

    The near-50-percent thinning of the stratospheric ozone layer over the Antarctic, with increased passage of mid-UV radiation to the surface of the Southern Ocean, has prompted concern over possible radiation damage to the near-surface phytoplankton communities that are the bases of Antarctic marine ecosystems. As the ozone layer thinned, a 6-week study of the marginal ice zone of the Bellingshousen Sea in the austral spring of 1990 noted sea-surface and depth-dependent ratios of mid-UV irradiance to total irradiance increased, and mid-UV inhibition of photosynthesis increased. A 6-12 percent reduction in primary production associated with ozone depletion was estimated to have occurred over the course of the present study.

  10. Pricing of Water Resources With Depletable Externality: The Effects of Pollution Charges

    NASA Astrophysics Data System (ADS)

    Kitabatake, Yoshifusa

    1990-04-01

    With an abstraction of a real-world situation, the paper views water resources as a depletable capital asset which yields a stream of services such as water supply and the assimilation of pollution discharge. The concept of the concave or convex water resource depletion function is then introduced and applied to a general two-sector, three-factor model. The main theoretical contribution is to prove that when the water resource depletion function is a concave rather than a convex function of pollution, it is more likely that gross regional income will increase with a higher pollution charge policy. The concavity of the function is meant to imply that with an increase in pollution released, the ability of supplying water at a certain minimum quality level diminishes faster and faster. A numerical example is also provided.

  11. Depletion and capture: revisiting "the source of water derived from wells".

    PubMed

    Konikow, L F; Leake, S A

    2014-09-01

    A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion and capture relative to groundwater withdrawals (extraction or pumpage) have not previously been well characterized. This study assesses the partitioning of long-term cumulative withdrawal volumes into fractions derived from storage depletion and capture, where capture includes both increases in recharge and decreases in discharge. Numerical simulation of a hypothetical groundwater basin is used to further illustrate some of Theis' (1940) principles, particularly when capture is constrained by insufficient available water. Most prior studies of depletion and capture have assumed that capture is unconstrained through boundary conditions that yield linear responses. Examination of real systems indicates that capture and depletion fractions are highly variable in time and space. For a large sample of long-developed groundwater systems, the depletion fraction averages about 0.15 and the capture fraction averages about 0.85 based on cumulative volumes. Higher depletion fractions tend to occur in more arid regions, but the variation is high and the correlation coefficient between average annual precipitation and depletion fraction for individual systems is only 0.40. Because 85% of long-term pumpage is derived from capture in these real systems, capture must be recognized as a critical factor in assessing water budgets, groundwater storage depletion, and sustainability of groundwater development. Most capture translates into streamflow depletion, so it can detrimentally impact ecosystems. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  12. Tritium, deuterium, and oxygen-18 in water collected from unsaturated sediments near a low-level radioactive-waste burial site south of Beatty, Nevada

    USGS Publications Warehouse

    Prudic, David E.; Stonestrom, David A.; Striegl, Robert G.

    1997-01-01

    Pore water was extracted in March 1996 from cores collected from test holes UZB-1 and UZB-2 drilled November 1992 and September 1993, respectively, in the Amargosa Desert south of Beatty, Nevada. The test holes are part of a study to determine factors affecting water and gas movement through unsaturated sediments. The holes are about 100 meters south of the southwest corner of the fence enclosing a commercial burial area for low-level radioactive waste. Water vapor collected from test hole UZB-2 in April 1994 and July 1995 had tritium concentrations greater than would be expected from atmospheric deposition. An apparatus was built in which pore water was extracted by cryodistillation from the previously obtained core samples. The extracted core water was analyzed for the radioactive isotope tritium and for the stable isotopes deuterium (D) and oxygen-18 (18O). The isotopic composition of core water was compared with that of water vapor previously collected from air ports in test hole UZB-2 and to additional samples collected during May 1996. Core water becomes increasingly depleted in D and 18O from the land surface to a depth of 30 meters, indicating that net evaporation of water is occurring near the land surface. Below a depth of 30 meters the stable-isotopic composition of core water becomes nearly constant and roughly equal to that of ground water. The stable isotopes plot on an evaporation trend. The source of the partly evaporated water could be either ground water or past precipitation having the same average isotopic composition as ground water but not modern precipitation, based on 18 months of record. Profiles of D and 18O in water vapor roughly parallel those in core water. The stable isotopes of core water appear to be in isotopic equilibrium with water vapor from UZB-2 when temperature-dependent fractionation is considered. The data are consistent with the hypothesis of evaporative discharge of ground water at the land surface. The concentration of

  13. Slow molecular dynamics of water in a lyotropic complex fluid studied by deuterium conventional and spin-lattice relaxometry NMR.

    PubMed

    Rodríguez, C R; Pusiol, D J; Figueiredo Neto, A M; Seitter, R-O

    2002-03-01

    A nuclear magnetic resonance study of protons and deuterons in the mesomorphic phases of the micellar lyotropic mixture potassium laurate/1-decanol/heavy water is reported. The slow dynamical behavior of water molecules has been investigated with deuterons spin-lattice relaxation dispersion in the Larmor frequency range 10(3)water slow reorientational dynamics is closely related to the slow reorientation of the micellar aggregates. In addition, conventional deuterium nuclear magnetic resonance at nu(L)=4.2x10(7) Hz spectra has been measured at different places in the phase diagram. The line shapes show a quadrupolar splitting in nematic phases, meanwhile in the isotropic phase the spectral structure collapses in a single line. This indicates that in the nematic phases the water reorientations are not enough to average the deuterons quadrupolar Hamiltonian. On the other hand, fast isotropic water reorientations reduce the quadrupolar interactions in the isotropic phase.

  14. The Effect of Climate Change on Ozone Depletion through Changes in Stratospheric Water Vapour

    NASA Technical Reports Server (NTRS)

    Kirk-Davidoff, Daniel B.; Hintsa, Eric J.; Anderson, James G.; Keith, David W.

    1999-01-01

    Several studies have predicted substantial increases in Arctic ozone depletion due to the stratospheric cooling induced by increasing atmospheric CO2 concentrations. But climate change may additionally influence Arctic ozone depletion through changes in the water vapor cycle. Here we investigate this possibility by combining predictions of tropical tropopause temperatures from a general circulation model with results from a one-dimensional radiative convective model, recent progress in understanding the stratospheric water vapor budget, modelling of heterogeneous reaction rates and the results of a general circulation model on the radiative effect of increased water vapor. Whereas most of the stratosphere will cool as greenhouse-gas concentrations increase, the tropical tropopause may become warmer, resulting in an increase of the mean saturation mixing ratio of water vapor and hence an increased transport of water vapor from the troposphere to the stratosphere. Stratospheric water vapor concentration in the polar regions determines both the critical temperature below which heterogeneous reactions on cold aerosols become important (the mechanism driving enhanced ozone depletion) and the temperature of the Arctic vortex itself. Our results indicate that ozone loss in the later winter and spring Arctic vortex depends critically on water vapor variations which are forced by sea surface temperature changes in the tropics. This potentially important effect has not been taken into account in previous scenarios of Arctic ozone loss under climate change conditions.

  15. Water accounting and vulnerability evaluation (WAVE): considering atmospheric evaporation recycling and the risk of freshwater depletion in water footprinting.

    PubMed

    Berger, Markus; van der Ent, Ruud; Eisner, Stephanie; Bach, Vanessa; Finkbeiner, Matthias

    2014-04-15

    Aiming to enhance the analysis of water consumption and resulting consequences along the supply chain of products, the water accounting and vulnerability evaluation (WAVE) model is introduced. On the accounting level, atmospheric evaporation recycling within drainage basins is considered for the first time, which can reduce water consumption volumes by up to 32%. Rather than predicting impacts, WAVE analyzes the vulnerability of basins to freshwater depletion. Based on local blue water scarcity, the water depletion index (WDI) denotes the risk that water consumption can lead to depletion of freshwater resources. Water scarcity is determined by relating annual water consumption to availability in more than 11,000 basins. Additionally, WDI accounts for the presence of lakes and aquifers which have been neglected in water scarcity assessments so far. By setting WDI to the highest value in (semi)arid basins, absolute freshwater shortage is taken into account in addition to relative scarcity. This avoids mathematical artifacts of previous indicators which turn zero in deserts if consumption is zero. As illustrated in a case study of biofuels, WAVE can help to interpret volumetric water footprint figures and, thus, promotes a sustainable use of global freshwater resources.

  16. 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

  17. Comparative Plant Water Relations and Soil Water Depletion Patterns of Three Seral Shrub Species on Forest Sites in Southwestern Oregon

    Treesearch

    Jon C. Reggelbrugge

    1997-01-01

    ABSTRACT. We compared stomatal conductance, transpiration, plant water potential, and soil moisture depletion patterns for three shrub species common on early seral forest sites in southwestern Oregon following logging or fire. Our goal was to determine which of these species were more likely to be the strongest competitors with regenerating conifers. The three species...

  18. Semiconductor-based photoelectrochemical water splitting at the limit of very wide depletion region

    DOE PAGES

    Liu, Mingzhao; Lyons, John L.; Yan, Danhua H.; ...

    2015-11-23

    In semiconductor-based photoelectrochemical (PEC) water splitting, carrier separation and delivery largely relies on the depletion region formed at the semiconductor/water interface. As a Schottky junction device, the trade-off between photon collection and minority carrier delivery remains a persistent obstacle for maximizing the performance of a water splitting photoelectrode. Here, it is demonstrated that the PEC water splitting efficiency for an n-SrTiO 3 (n-STO) photoanode is improved very significantly despite its weak indirect band gap optical absorption (α < 10⁴ cm⁻¹), by widening the depletion region through engineering its doping density and profile. Graded doped n-SrTiO 3 photoanodes are fabricated withmore » their bulk heavily doped with oxygen vacancies but their surface lightly doped over a tunable depth of a few hundred nanometers, through a simple low temperature re-oxidation technique. The graded doping profile widens the depletion region to over 500 nm, thus leading to very efficient charge carrier separation and high quantum efficiency (>70%) for the weak indirect transition. As a result, this simultaneous optimization of the light absorption, minority carrier (hole) delivery, and majority carrier (electron) transport by means of a graded doping architecture may be useful for other indirect band gap photocatalysts that suffer from a similar problem of weak optical absorption.« less

  19. Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques.

    Treesearch

    F.C. Meinzer; J.R. Brooks; J.-C. Domec; B.L. Gartner; J.M. Warren; D.R. Woodruff; K. Bible; D.C. Shaw

    2006-01-01

    The volume and complexity of their vascular systems make the dynamics of tong-distance water transport in large trees difficult to study. We used heat and deuterated water (D20) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii...

  20. DYNAMICS OF WATER TRANSPORT AND STORAGE IN CONIFERS STUDIED WITH DEUTERIUM AND HEAT TRACING TECHNIQUES

    EPA Science Inventory

    The volume and complexity of their vascular systems make the dynamics of long-distance water transport difficult to study. We used heat and deuterated water (D2O) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the co...

  1. Groundwater Depletion During Drought Threatens Future Water Security of the Colorado River Basin

    NASA Technical Reports Server (NTRS)

    Castle, Stephanie L.; Thomas, Brian F.; Reager, John T.; Rodell, Matthew; Swenson, Sean C.; Famiglietti, James S.

    2014-01-01

    Streamflow of the Colorado River Basin is the most overallocated in the world. Recent assessment indicates that demand for this renewable resource will soon outstrip supply, suggesting that limited groundwater reserves will play an increasingly important role in meeting future water needs. Here we analyze 9 years (December 2004 to November 2013) of observations from the NASA Gravity Recovery and Climate Experiment mission and find that during this period of sustained drought, groundwater accounted for 50.1 cu km of the total 64.8 cu km of freshwater loss. The rapid rate of depletion of groundwater storage (5.6 +/- 0.4 cu km/yr) far exceeded the rate of depletion of Lake Powell and Lake Mead. Results indicate that groundwater may comprise a far greater fraction of Basin water use than previously recognized, in particular during drought, and that its disappearance may threaten the long-term ability to meet future allocations to the seven Basin states.

  2. Groundwater depletion during drought threatens future water security of the Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Castle, Stephanie L.; Thomas, Brian F.; Reager, John T.; Rodell, Matthew; Swenson, Sean C.; Famiglietti, James S.

    2014-08-01

    Streamflow of the Colorado River Basin is the most overallocated in the world. Recent assessment indicates that demand for this renewable resource will soon outstrip supply, suggesting that limited groundwater reserves will play an increasingly important role in meeting future water needs. Here we analyze 9 years (December 2004 to November 2013) of observations from the NASA Gravity Recovery and Climate Experiment mission and find that during this period of sustained drought, groundwater accounted for 50.1 km3 of the total 64.8 km3 of freshwater loss. The rapid rate of depletion of groundwater storage (-5.6 ± 0.4 km3 yr-1) far exceeded the rate of depletion of Lake Powell and Lake Mead. Results indicate that groundwater may comprise a far greater fraction of Basin water use than previously recognized, in particular during drought, and that its disappearance may threaten the long-term ability to meet future allocations to the seven Basin states.

  3. Ground-water storage depletion in Pahrump Valley, Nevada-California, 1962-75

    USGS Publications Warehouse

    Harrill, James R.

    1982-01-01

    During the 13-year period, February 1962 to February 1975, about 540,000 acre-feet of ground water was pumped from Pahrump Valley. This resulted in significant water-level declines along the base of the Pahrump and Manse fans where pumping was concentrated. Maximum observed net decline was slightly more than 60 feet. Much smaller declines occurred in the central valley, and locally, water levels in some shallow wells rose due to recharge derived from the deep percolation of irrigation water. The pumping resulted in about 219,000 acre-feet of storage depletion. Of this, 155,000 acre-feet was from the draining of unconsolidated material, 46,000 was from compaction of fine-grained sediments, and 18,000 acre-feet was from the elastic response of the aquifer and water. The total storage depletion was equal to about 40 percent of the total pumpage. The remaining pumped water was derived from the capture of natural ground-water discharge and reuse of pumped water that had recirculated back to ground water. Natural recharge to and discharge from the ground-water system is estimated to be 37,000 acre-feet per year. Of this, 18,000 acre-feet per year leaves the area as subsurface outflow through carbonate-rock aquifers which form a multivalley flow system. The extent of this system was not precisely determined by this study. The most probable discharge area for this outflow is along the flood plain of the Amargosa River between the towns of Shoshone and Tecopa. This outflow probably cannot be economically captured by pumping from Pahrump Valley. Consequently, the maximum amount of natural discharge available for capture is 19,000 acre-feet per year. This is larger than the 12,000 acre-feet per year estimated in a previous study; the difference is due to different techniques used in the analysis. As of 1975, pumping was causing an overdraft of 11,000 acre-feet per year on the ground-water system. No new equilibrium is probable in the foreseeable future. Water levels will

  4. Impact of Preservation of Subsoil Water Act on Groundwater Depletion: The Case of Punjab, India.

    PubMed

    Tripathi, Amarnath; Mishra, Ashok K; Verma, Geetanjali

    2016-07-01

    Indian states like Punjab and Haryana, epicenters of the Green Revolution, are facing severe groundwater shortages and falling water tables. Recognizing it as a serious concern, the Government of Punjab enacted the Punjab Preservation of Subsoil Water Act in 2009 (or the 2009 act) to slow groundwater depletion. The objective of this study is to assess the impact of this policy on groundwater depletion, using panel data from 1985 to 2011. Results from this study find a robust effect of the 2009 act on reducing groundwater depletion. Our models for pre-monsoon, post-monsoon, and overall periods of analysis find that since implementation of the 2009 act, groundwater tables have improved significantly. Second, our study reveals that higher shares of tube wells per total cropped area and increased population density have led to a significant decline in the groundwater tables. On the other hand, rainfall and the share of area irrigated by surface water have had an augmenting effect on groundwater resources. In the two models, pre-monsoon and post-monsoon, this study shows that seasonality plays a key role in determining the groundwater table in Punjab. Specifically, monsoon rainfall has a very prominent impact on groundwater.

  5. The Depletion of Water During Dispersal of Planet-forming Disk Regions

    NASA Astrophysics Data System (ADS)

    Banzatti, A.; Pontoppidan, K. M.; Salyk, C.; Herczeg, G. J.; van Dishoeck, E. F.; Blake, G. A.

    2017-01-01

    We present a new velocity-resolved survey of 2.9 μm spectra of hot H2O and OH gas emission from protoplanetary disks, obtained with the Cryogenic Infrared Echelle Spectrometer at the VLT (R ˜ 96,000). With the addition of archival Spitzer-IRS spectra, this is the most comprehensive spectral data set of water vapor emission from disks ever assembled. We provide line fluxes at 2.9-33 μm that probe from the dust sublimation radius at ˜0.05 au out to the region of the water snow line. With a combined data set for 55 disks, we find a new correlation between H2O line fluxes and the radius of CO gas emission, as measured in velocity-resolved 4.7 μm spectra (R {}{co}), which probes molecular gaps in inner disks. We find that H2O emission disappears from 2.9 μm (hotter water) to 33 μm (colder water) as {R}{co} increases and expands out to the snow line radius. These results suggest that the infrared water spectrum is a tracer of inside-out water depletion within the snow line. It also helps clarify an unsolved discrepancy between water observations and models by finding that disks around stars of {M}\\star > 1.5 {M}⊙ generally have inner gaps with depleted molecular gas content. We measure radial trends in H2O, OH, and CO line fluxes that can be used as benchmarks for models to study the chemical composition and evolution of planet-forming disk regions at 0.05-20 au. We propose that JWST spectroscopy of molecular gas may be used as a probe of inner disk gas depletion, complementary to the larger gaps and holes detected by direct imaging and by ALMA.

  6. A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion

    NASA Astrophysics Data System (ADS)

    Sing, David K.; Fortney, Jonathan J.; Nikolov, Nikolay; Wakeford, Hannah R.; Kataria, Tiffany; Evans, Thomas M.; Aigrain, Suzanne; Ballester, Gilda E.; Burrows, Adam S.; Deming, Drake; Désert, Jean-Michel; Gibson, Neale P.; Henry, Gregory W.; Huitson, Catherine M.; Knutson, Heather A.; Lecavelier Des Etangs, Alain; Pont, Frederic; Showman, Adam P.; Vidal-Madjar, Alfred; Williamson, Michael H.; Wilson, Paul A.

    2016-01-01

    Thousands of transiting exoplanets have been discovered, but spectral analysis of their atmospheres has so far been dominated by a small number of exoplanets and data spanning relatively narrow wavelength ranges (such as 1.1-1.7 micrometres). Recent studies show that some hot-Jupiter exoplanets have much weaker water absorption features in their near-infrared spectra than predicted. The low amplitude of water signatures could be explained by very low water abundances, which may be a sign that water was depleted in the protoplanetary disk at the planet’s formation location, but it is unclear whether this level of depletion can actually occur. Alternatively, these weak signals could be the result of obscuration by clouds or hazes, as found in some optical spectra. Here we report results from a comparative study of ten hot Jupiters covering the wavelength range 0.3-5 micrometres, which allows us to resolve both the optical scattering and infrared molecular absorption spectroscopically. Our results reveal a diverse group of hot Jupiters that exhibit a continuum from clear to cloudy atmospheres. We find that the difference between the planetary radius measured at optical and infrared wavelengths is an effective metric for distinguishing different atmosphere types. The difference correlates with the spectral strength of water, so that strong water absorption lines are seen in clear-atmosphere planets and the weakest features are associated with clouds and hazes. This result strongly suggests that primordial water depletion during formation is unlikely and that clouds and hazes are the cause of weaker spectral signatures.

  7. A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion.

    PubMed

    Sing, David K; Fortney, Jonathan J; Nikolov, Nikolay; Wakeford, Hannah R; Kataria, Tiffany; Evans, Thomas M; Aigrain, Suzanne; Ballester, Gilda E; Burrows, Adam S; Deming, Drake; Désert, Jean-Michel; Gibson, Neale P; Henry, Gregory W; Huitson, Catherine M; Knutson, Heather A; des Etangs, Alain Lecavelier; Pont, Frederic; Showman, Adam P; Vidal-Madjar, Alfred; Williamson, Michael H; Wilson, Paul A

    2016-01-07

    Thousands of transiting exoplanets have been discovered, but spectral analysis of their atmospheres has so far been dominated by a small number of exoplanets and data spanning relatively narrow wavelength ranges (such as 1.1-1.7 micrometres). Recent studies show that some hot-Jupiter exoplanets have much weaker water absorption features in their near-infrared spectra than predicted. The low amplitude of water signatures could be explained by very low water abundances, which may be a sign that water was depleted in the protoplanetary disk at the planet's formation location, but it is unclear whether this level of depletion can actually occur. Alternatively, these weak signals could be the result of obscuration by clouds or hazes, as found in some optical spectra. Here we report results from a comparative study of ten hot Jupiters covering the wavelength range 0.3-5 micrometres, which allows us to resolve both the optical scattering and infrared molecular absorption spectroscopically. Our results reveal a diverse group of hot Jupiters that exhibit a continuum from clear to cloudy atmospheres. We find that the difference between the planetary radius measured at optical and infrared wavelengths is an effective metric for distinguishing different atmosphere types. The difference correlates with the spectral strength of water, so that strong water absorption lines are seen in clear-atmosphere planets and the weakest features are associated with clouds and hazes. This result strongly suggests that primordial water depletion during formation is unlikely and that clouds and hazes are the cause of weaker spectral signatures.

  8. Deuterium Enrichment in Stratospheric Molecular Hydrogen

    NASA Astrophysics Data System (ADS)

    Rahn, T.; Eiler, J.; McCarthy, M. C.; Boering, K. A.; Wennberg, P.; Atlas, E.; Donnelly, S.; Schauffler, S.

    2002-12-01

    Molecular hydrogen (H2) is the second most abundant reduced gas in the atmosphere (after methane) with a globally averaged mixing ratio of ~ 530 ppbv. Its largest source is believed to be photochemical oxidation of methane (C H4) and non-methane hydrocarbons (NMHCs); other recognized sources include biomass burning, fossil fuel burning, nitrogen fixation, and ocean degassing. As with other atmospheric trace gases, the stable isotopic content of H2 has the potential to help quantify various aspects of its production and destruction. The average deuterium content of H2 (expressed as δDH2) is enriched by ~110 ‰ relative to Vienna Standard Mean Ocean Water while CH4 in the troposphere, the precursor for photochemical H2 production, is depleted by ~ 90 ‰ relative to V-SMOW and similar values are expected for NMHCs. Both natural and anthropogenic combustion sources of H2 have been shown to be depleted in deuterium by 200 to 300 ‰ (Gerst and Quay, 2001; Rahn et al., 2002), and the ocean and N2 fixation sources are expected to be in near thermodynamic equilibrium with local H2O and should have deuterium levels of ~-700 ‰ (Rahn et al., 2002). In order to offset these deuterium depleted sources and account for the observed tropospheric δDH2, the balancing loss processes must discriminate against reaction with HD and/or the total fractionation associated with CH4 oxidation and the subsequent reactions leading to H2 must favor production of deuterated H2. We have analyzed a suite of stratospheric air samples in order to investigate the photochemical processes influencing the deuterium content of H2. While the mixing ratio of H2 is nearly constant, the deuterium content increases such that δD=440 ‰ in samples with a stratospheric mean age of ~6 years. The constant mixing ratio results from the fact that production due to CH4 oxidation and loss due to H2 oxidation are approximately equal. The observed trend in δD of stratospheric H2 can only be accounted for by an

  9. Simulation of groundwater conditions and streamflow depletion to evaluate water availability in a Freeport, Maine, watershed

    USGS Publications Warehouse

    Nielsen, Martha G.; Locke, Daniel B.

    2012-01-01

    , the public-supply withdrawals (105.5 million gallons per year (Mgal/yr)) were much greater than those for any other category, being almost 7 times greater than all domestic well withdrawals (15.3 Mgal/yr). Industrial withdrawals in the study area (2.0 Mgal/yr) are mostly by a company that withdraws from an aquifer at the edge of the Merrill Brook watershed. Commercial withdrawals are very small (1.0 Mgal/yr), and no irrigation or other agricultural withdrawals were identified in this study area. A three-dimensional, steady-state groundwater-flow model was developed to evaluate stream-aquifer interactions and streamflow depletion from pumping, to help refine the conceptual model, and to predict changes in streamflow resulting from changes in pumping and recharge. Groundwater levels and flow in the Freeport aquifer study area were simulated with the three-dimensional, finite-difference groundwater-flow modeling code, MODFLOW-2005. Study area hydrology was simulated with a 3-layer model, under steady-state conditions. The groundwater model was used to evaluate changes that could occur in the water budgets of three parts of the local hydrologic system (the Harvey Brook watershed, the Merrill Brook watershed, and the buried aquifer from which pumping occurs) under several different climatic and pumping scenarios. The scenarios were (1) no pumping well withdrawals; (2) current (2009) pumping, but simulated drought conditions (20-percent reduction in recharge); (3) current (2009) recharge, but a 50-percent increase in pumping well withdrawals for public supply; and (4) drought conditions and increased pumping combined. In simulated drought situations, the overall recharge to the buried valley is about 15 percent less and the total amount of streamflow in the model area is reduced by about 19 percent. Without pumping, infiltration to the buried valley aquifer around the confining unit decreased by a small amount (0.05 million gallons per day (Mgal/d)), and discharge to the

  10. Triple Oxygen and Deuterium Isotopes in Gypsum Hydration Water for Quantitative Paleo-humidity Reconstructions

    NASA Astrophysics Data System (ADS)

    Gázquez, F.; Evans, N. P.; Herwartz, D.; Bauska, T. K.; Morellon, M.; Surma, J.; Moreno, A.; Staubwasser, M.; Valero-Garces, B. L.; Hodell, D. A.

    2016-12-01

    Variations in atmospheric relative humidity (RH) and precipitation may have driven major ecological and sociocultural changes during the Quaternary but quantitative proxies for RH are scarce and difficult to calibrate. The isotopic composition of lake water (δ17O, δ18O and δD, and derived d-excess and 17Oexcess) is sensitive to changes in atmospheric RH and temperature. Because 17Oexcess is less sensitive to temperature effects than the d-excess during evaporation, combining 17Oexces and d-excess provide information about the relative effects of humidity and temperature change in the hydrological cycle. Here we demonstrate how the isotope ratios of hydration water measured in gypsum from lake sediments can be used to reconstruct past changes in RH. We present stable isotopes of gypsum hydration water from two lake systems across the last deglaciation. In Lake Estanya (NE, Spain) the 17Oexcess and d-excess of the paleo-lake water indicates that evaporation of water during the Younger Dryas (ca. 12 kyr BP) occurred under RH conditions of 40-45%. Environmental humidity gradually increased over the Preboreal period and stabilised at 70-75% during the Holocene until present. In Lake Peten-Itza (Guatemala), the isotopic values of the paleo-lake waters during the Late Glacial can be explained by a lowering of atmospheric RH by 10% and cooling of temperature by 5oC compared with modern conditions. Our results demonstrate that the coupled measurement of 17Oexcess and d-excess of gypsum hydration water in lake sediments can provide a useful quantitative proxy for paleo-humidity.

  11. High-throughput simultaneous determination of plasma water deuterium and 18-oxygen enrichment using a high-temperature conversion elemental analyzer with isotope ratio mass spectrometry.

    PubMed

    Richelle, M; Darimont, C; Piguet-Welsch, C; Fay, L B

    2004-01-01

    This paper presents a high-throughput method for the simultaneous determination of deuterium and oxygen-18 (18O) enrichment of water samples isolated from blood. This analytical method enables rapid and simple determination of these enrichments of microgram quantities of water. Water is converted into hydrogen and carbon monoxide gases by the use of a high-temperature conversion elemental analyzer (TC-EA), that are then transferred on-line into the isotope ratio mass spectrometer. Accuracy determined with the standard light Antartic precipitation (SLAP) and Greenland ice sheet precipitation (GISP) is reliable for deuterium and 18O enrichments. The range of linearity is from 0 up to 0.09 atom percent excess (APE, i.e. -78 up to 5725 delta per mil (dpm)) for deuterium enrichment and from 0 up to 0.17 APE (-11 up to 890 dpm) for 18O enrichment. Memory effects do exist but can be avoided by analyzing the biological samples in quintuplet. This method allows the determination of 1440 samples per week, i.e. 288 biological samples per week. Copyright 2004 John Wiley & Sons, Ltd.

  12. Deuterium excess reveals diurnal sources of water vapor in forest air.

    PubMed

    Lai, Chun-Ta; Ehleringer, James R

    2011-01-01

    An understanding of atmospheric water vapor content and its isotopic composition is important if we are to be able to model future water vapor dynamics and their potential feedback on future climate change. Here we present diurnal and vertical patterns of water isotope ratios in forest air (δ(2)H(v) and δ(18)O(v)) not observed previously. Water vapor observed at three heights over 3 consecutive days in a coniferous forest in the Pacific Northwest of the United States, shows a stratified nocturnal structure of δ(2)H(v) and δ(18)O(v), with the most positive values consistently observed above the canopy (60 m). Differences between 0.5 m and 60 m range between 2-6‰ for δ(18)O and 20-40‰ for δ(2)H at night. Using a box model, we simulated H(2)O isotope fluxes and showed that the low to high δ(2)H(v) and δ(18)O(v) profiles can be explained by the vapor flux associated with evaporation from the forest floor and canopy transpiration. We used d-excess as a diagnostic tracer to identify processes that contribute to the diurnal variation in atmospheric moisture. Values of d-excess derived from water vapor measurements showed a repeated diel pattern, with the lowest values occurring in the early morning and the highest values occurring at midday. The isotopic composition of rain water, collected during a light rain event in the first morning of our experiment, suggested that considerable below-cloud secondary evaporation occurred during the descent of raindrops. We conclude that atmospheric entrainment appears to drive the isotopic variation of water vapor in the early morning when the convective boundary layer rapidly develops, while evapotranspiration becomes more important in the mid-afternoon as a primary moisture source of water vapor in this forest. Our results demonstrate the interplay between the effects of vegetation and boundary layer mixing under the influence of rain evaporation, which has implications for larger-scale predictions of precipitation

  13. Use of Superposition Models to Simulate Possible Depletion of Colorado River Water by Ground-Water Withdrawal

    USGS Publications Warehouse

    Leake, Stanley A.; Greer, William; Watt, Dennis; Weghorst, Paul

    2008-01-01

    According to the 'Law of the River', wells that draw water from the Colorado River by underground pumping need an entitlement for the diversion of water from the Colorado River. Consumptive use can occur through direct diversions of surface water, as well as through withdrawal of water from the river by underground pumping. To develop methods for evaluating the need for entitlements for Colorado River water, an assessment of possible depletion of water in the Colorado River by pumping wells is needed. Possible methods include simple analytical models and complex numerical ground-water flow models. For this study, an intermediate approach was taken that uses numerical superposition models with complex horizontal geometry, simple vertical geometry, and constant aquifer properties. The six areas modeled include larger extents of the previously defined river aquifer from the Lake Mead area to the Yuma area. For the modeled areas, a low estimate of transmissivity and an average estimate of transmissivity were derived from statistical analyses of transmissivity data. Aquifer storage coefficient, or specific yield, was selected on the basis of results of a previous study in the Yuma area. The USGS program MODFLOW-2000 (Harbaugh and others, 2000) was used with uniform 0.25-mile grid spacing along rows and columns. Calculations of depletion of river water by wells were made for a time of 100 years since the onset of pumping. A computer program was set up to run the models repeatedly, each time with a well in a different location. Maps were constructed for at least two transmissivity values for each of the modeled areas. The modeling results, based on the selected transmissivities, indicate that low values of depletion in 100 years occur mainly in parts of side valleys that are more than a few tens of miles from the Colorado River.

  14. Natural abundance deuterium and 18-oxygen effects on the precision of the doubly labeled water method.

    PubMed

    Horvitz, M A; Schoeller, D A

    2001-06-01

    The doubly labeled water method for measuring total energy expenditure is subject to error from natural variations in the background 2H and 18O in body water. There is disagreement as to whether the variations in background abundances of the two stable isotopes covary and what relative doses of 2H and 18O minimize the impact of variation on the precision of the method. We have performed two studies to investigate the amount and covariance of the background variations. These were a study of urine collected weekly from eight subjects who remained in the Madison, WI locale for 6 wk and frequent urine samples from 14 subjects during round-trip travel to a locale > or = 500 miles from Madison, WI. Background variation in excess of analytical error was detected in six of the eight nontravelers, and covariance was demonstrated in four subjects. Background variation was detected in all 14 travelers, and covariance was demonstrated in 11 subjects. The median slopes of the regression lines of delta2H vs. delta18O were 6 and 7, respectively. Modeling indicated that 2H and 18O doses yielding a 6:1 ratio of final enrichments should minimize this error introduced to the doubly labeled water method.

  15. Natural abundance deuterium and 18-oxygen effects on the precision of the doubly labeled water method

    NASA Technical Reports Server (NTRS)

    Horvitz, M. A.; Schoeller, D. A.

    2001-01-01

    The doubly labeled water method for measuring total energy expenditure is subject to error from natural variations in the background 2H and 18O in body water. There is disagreement as to whether the variations in background abundances of the two stable isotopes covary and what relative doses of 2H and 18O minimize the impact of variation on the precision of the method. We have performed two studies to investigate the amount and covariance of the background variations. These were a study of urine collected weekly from eight subjects who remained in the Madison, WI locale for 6 wk and frequent urine samples from 14 subjects during round-trip travel to a locale > or = 500 miles from Madison, WI. Background variation in excess of analytical error was detected in six of the eight nontravelers, and covariance was demonstrated in four subjects. Background variation was detected in all 14 travelers, and covariance was demonstrated in 11 subjects. The median slopes of the regression lines of delta2H vs. delta18O were 6 and 7, respectively. Modeling indicated that 2H and 18O doses yielding a 6:1 ratio of final enrichments should minimize this error introduced to the doubly labeled water method.

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

    SciTech Connect

    Kurz, J.L.; Lee, J.

    1980-07-30

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

  17. Validation of bioelectrical impedance analysis for total body water assessment against the deuterium dilution technique in Asian children.

    PubMed

    Liu, A; Byrne, N M; Ma, G; Nasreddine, L; Trinidad, T P; Kijboonchoo, K; Ismail, M N; Kagawa, M; Poh, B K; Hills, A P

    2011-12-01

    To develop and cross-validate bioelectrical impedance analysis (BIA) prediction equations of total body water (TBW) and fat-free mass (FFM) for Asian pre-pubertal children from China, Lebanon, Malaysia, Philippines and Thailand. Height, weight, age, gender, resistance and reactance measured by BIA were collected from 948 Asian children (492 boys and 456 girls) aged 8-10 years from the five countries. The deuterium dilution technique was used as the criterion method for the estimation of TBW and FFM. The BIA equations were developed using stepwise multiple regression analysis and cross-validated using the Bland-Altman approach. The BIA prediction equation for the estimation of TBW was as follows: TBW=0.231 × height(2)/resistance+0.066 × height+0.188 × weight+0.128 × age+0.500 × sex-0.316 × Thais-4.574 (R (2)=88.0%, root mean square error (RMSE)=1.3 kg), and for the estimation of FFM was as follows: FFM=0.299 × height(2)/resistance+0.086 × height+0.245 × weight+0.260 × age+0.901 × sex-0.415 × ethnicity (Thai ethnicity =1, others = 0)-6.952 (R (2)=88.3%, RMSE=1.7 kg). No significant difference between measured and predicted values for the whole cross-validation sample was found. However, the prediction equation for estimation of TBW/FFM tended to overestimate TBW/FFM at lower levels whereas underestimate at higher levels of TBW/FFM. Accuracy of the general equation for TBW and FFM was also valid at each body mass index category. Ethnicity influences the relationship between BIA and body composition in Asian pre-pubertal children. The newly developed BIA prediction equations are valid for use in Asian pre-pubertal children.

  18. The role of water in generating Fe-depletion and the calc-alkaline trend

    NASA Astrophysics Data System (ADS)

    Zimmer, M. M.; Plank, T.

    2006-12-01

    Describing a magmatic suite as calc-alkaline (CA) or tholeiitic (TH) is a first order characterization, but existing classification schemes (AFM ternary plots and FeO*/MgO vs. SiO2) may convolute magmatic processes and can result in contradictory classification. The salient feature of TH vs. CA evolution is the extent of Fe enrichment or depletion in the magma. A plot of FeO* vs. MgO provides the most straightforward way to quantify Fe enrichment and to develop models for its origin. We present a new quantitative classification utilizing the FeO*-MgO plot, the tholeiitic index (THI) = Fe3-5/Fe8 (Fe3-5=average FeO* at 3-5 wt% MgO; Fe8=FeO* at 8 wt% MgO). THI of 1.2 indicates 20% FeO* enrichment from a magma's starting composition at Fe8, while THI of 0.8 indicates 20% depletion in FeO*. A magmatic suite is CA if THI is <1, and TH if THI is >1. Arcs range from 0.6 to 1.1, back arc basins from 1.1-1.3, and MORBs are \\ge1.6. This classification allows comparison of magmatic evolution on a global basis, regardless of starting composition, and is useful for quantitative comparison to liquid line of descent models. Hypotheses for generating CA magmas include high water contents, high pressure of crystallization, high oxygen fugacity, and high Mg# andesitic starting compositions. In order to test the control of H2O, we compare the THI to average magmatic water contents from undegassed melt inclusions and glasses (S>1000 ppm or CO2>50 ppm) from twenty-eight arc volcanoes and back arc basins, including new water contents from seven Aleutian volcanoes. The resulting negative correlation (R2=0.8) between water concentration and THI (with end-members at 0.8 wt% H2O, THI =1.3 and 6.1 wt% H2O, THI = 0.6) suggests water plays a fundamental role in generating the CA fractionation trend. MORB data plot off the trend at a higher THI, possibly related to lower oxygen fugacity during melting and/or crystallization. Models using the pMelts program are consistent with experimentally

  19. Water Sorption and Vapor-Phase Deuterium Exchange Studies on Methemoglobin CC, SC, SS, AS, and AA

    PubMed Central

    Killion, Philip J.; Cameron, Bruce F.

    1972-01-01

    Five hemoglobins whose genetic relationship to one another involves one set of alleles, hemoglobins CC, SC, SS, AS, and AA, were studied in the Met form. Two different investigations were conducted at 28°C on these methemoglobins within a McBain gravimetric sorption system: sorption of H2O vapor and vapor-phase deuterium-hydrogen exchange. For each of the five samples there was close agreement between the per cent hydration of polar sites as determined from sorption studies and the maximum per cent of labile hydrogens that were exchanged during the vapor-phase deuterium exchange study. Both studies measured a slight increase in the number of polar sites accessible to H2O or D2O vapor for those samples in which the substituent in the sixth position from the N-terminus of the two β-chains had a positively charged side chain and a slight decrease for those in which the substituent had a negatively charged side chain. The in-exchange of deuterium for hydrogen occurred at a faster observed rate than the out-exchange of hydrogen for deuterium. PMID:5030563

  20. Electrical-analog analysis of ground-water depletion in central Arizona

    USGS Publications Warehouse

    Anderson, T.W.

    1968-01-01

    The Salt River Valley and the lower Santa Cruz River basin are the two largest agricultural areas in Arizona. The extensive use of ground water for irrigation has resulted in the need for a thorough appraisal of the present and future ground-water resources. The ground-water reservoir provides 80 percent (3.2 million acre-feet) of the total annual water supply. The amount of water pumped greatly exceeds the rate at which the ground-water supply is being replenished and has resulted in water-level declines of as much as 20 feet per year in some places. The depletion problem is of economic importance because ground water will become more expensive as pumping lifts increase and well yields decrease. The use of electrical-analog modeling techniques has made it possible to predict future ground-water levels under conditions of continued withdrawal in excess of the rate of replenishment. The electrical system is a representation of the hydrologic system: resistors and capacitors represent transmissibility and storage coefficients. The analogy between the two systems is accepted when the data obtained from the model closely match the field data in this instance, measured water-level change since 1923. The prediction of future water-table conditions is accomplished by a simple extension of the pumping trends to determine the resultant effect on the regional water levels. The results of this study indicate the probable depths to water in central Arizona in 1974 and 1984 if the aquifer characteristics are accurately modeled and if withdrawal of ground water continues at the same rate and under the tame areal distribution as existed between 1958 and 1964. The greatest depths to water in 1984 will be more than 700 feet near Stanfield and more than 650 feet in Deer Valley and northeast of Gilbert. South of Eloy and northwest of Litchfield Park, a static water level of more than 550 feet is predicted. The total water-level decline in the 20-year period 1964-84 at the deepest

  1. Expert stakeholder attitudes and support for alternative water sources in a groundwater depleted region.

    PubMed

    Boyer, Treavor H; Overdevest, Christine; Christiansen, Lisa; Ishii, Stephanie K L

    2012-10-15

    The main objectives of this research were to quantify the risks/benefits and impacts of alternative water sources (AWSs) as perceived by expert stakeholders and to evaluate the overall support for multiple AWSs by expert stakeholders. The St. Johns River (SJR) basin, FL, USA was chosen as a case study for AWSs because it is a fresh groundwater depleted region and there are ongoing activities related to water supply planning. Expert stakeholders included federal, state, and local governments, public utilities, consulting engineering and industry, and environmental and social non-governmental organizations. AWSs under consideration in the SJR basin include surface water, desalination, water reclamation, and water conservation. A two-phase research approach was followed that focused on expert stakeholders. First, an elicitation study was used to identify salient beliefs about AWSs. Open-ended questions were asked about the risks/benefits of AWSs in terms of the three pillars of sustainability: ecological, economic, and human health impacts. Second, an online survey was constructed using beliefs identified during the elicitation study. The online survey was used to quantify attitudes toward and overall support for AWSs. The salient beliefs of expert stakeholders were dominated by the ecological pillar of sustainability. The support of expert stakeholders for AWSs, from least favorable to most favorable, was surface water withdrawalswater reclamation<water conservation, and was shaped by attitudes. The results of this research provide an improved understanding of the beliefs and attitudes that influence decision-makers involved in water supply planning. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Evaluation of simplified stream-aquifer depletion models for water rights administration

    USGS Publications Warehouse

    Sophocleous, Marios; Koussis, Antonis; Martin, J.L.; Perkins, S.P.

    1995-01-01

    We assess the predictive accuracy of Glover's (1974) stream-aquifer analytical solutions, which are commonly used in administering water rights, and evaluate the impact of the assumed idealizations on administrative and management decisions. To achieve these objectives, we evaluate the predictive capabilities of the Glover stream-aquifer depletion model against the MODFLOW numerical standard, which, unlike the analytical model, can handle increasing hydrogeologic complexity. We rank-order and quantify the relative importance of the various assumptions on which the analytical model is based, the three most important being: (1) streambed clogging as quantified by streambed-aquifer hydraulic conductivity contrast; (2) degree of stream partial penetration; and (3) aquifer heterogeneity. These three factors relate directly to the multidimensional nature of the aquifer flow conditions. From these considerations, future efforts to reduce the uncertainty in stream depletion-related administrative decisions should primarily address these three factors in characterizing the stream-aquifer process. We also investigate the impact of progressively coarser model grid size on numerically estimating stream leakage and conclude that grid size effects are relatively minor. Therefore, when modeling is required, coarser model grids could be used thus minimizing the input data requirements.

  3. Processes that generate and deplete liquid water and snow in thin midlevel mixed-phase clouds

    NASA Astrophysics Data System (ADS)

    Smith, Adam J.; Larson, Vincent E.; Niu, Jianguo; Kankiewicz, J. Adam; Carey, Lawrence D.

    2009-06-01

    This paper uses a numerical model to investigate microphysical, radiative, and dynamical processes in mixed-phase altostratocumulus clouds. Three cloud cases are chosen for study, each of which was observed by aircraft during the fifth or ninth Complex Layered Cloud Experiment (CLEX). These three clouds are numerically modeled using large-eddy simulation (LES). The observed and modeled clouds consist of a mixed-phase layer with a quasi-adiabatic profile of liquid, and a virga layer below that consists of snow. A budget of cloud (liquid) water mixing ratio is constructed from the simulations. It shows that large-scale ascent/descent, radiative cooling/heating, turbulent transport, and microphysical processes are all significant. Liquid is depleted indirectly via depositional growth of snow (the Bergeron-Findeisen process). This process is more influential than depletion of liquid via accretional growth of snow. Also constructed is a budget of snow mixing ratio, which turns out to be somewhat simpler. It shows that snow grows by deposition in and below the liquid (mixed-phase) layer, and sublimates in the remainder of the virga region below. The deposition and sublimation are balanced primarily by sedimentation, which transports the snow from the growth region to the sublimation region below. In our three clouds, the vertical extent of the virga layer is influenced more by the profile of saturation ratio below the liquid (mixed-phase) layer than by the mixing ratio of snow at the top of the virga layer.

  4. Effect of hypolimnetic oxygenation on oxygen depletion rates in two water-supply reservoirs.

    PubMed

    Gantzer, Paul A; Bryant, Lee D; Little, John C

    2009-04-01

    Oxygenation systems, such as bubble-plume diffusers, are used to improve water quality by replenishing dissolved oxygen (DO) in the hypolimnia of water-supply reservoirs. The diffusers induce circulation and mixing, which helps distribute DO throughout the hypolimnion. Mixing, however, has also been observed to increase hypolimnetic oxygen demand (HOD) during system operation, thus accelerating oxygen depletion. Two water-supply reservoirs (Spring Hollow Reservoir (SHR) and Carvins Cove Reservoir (CCR)) that employ linear bubble-plume diffusers were studied to quantify diffuser effects on HOD. A recently validated plume model was used to predict oxygen addition rates. The results were used together with observed oxygen accumulation rates to evaluate HOD over a wide range of applied gas flow rates. Plume-induced mixing correlated well with applied gas flow rate and was observed to increase HOD. Linear relationships between applied gas flow rate and HOD were found for both SHR and CCR. HOD was also observed to be independent of bulk hypolimnion oxygen concentration, indicating that HOD is controlled by induced mixing. Despite transient increases in HOD, oxygenation caused an overall decrease in background HOD, as well as a decrease in induced HOD during diffuser operation, over several years. This suggests that the residual or background oxygen demand decreases from one year to the next. Despite diffuser-induced increases in HOD, hypolimnetic oxygenation remains a viable method for replenishing DO in thermally-stratified water-supply reservoirs such as SHR and CCR.

  5. Photosynthetic performance of invasive Pinus ponderosa and Juniperus virginiana seedlings under gradual soil water depletion.

    PubMed

    Bihmidine, S; Bryan, N M; Payne, K R; Parde, M R; Okalebo, J A; Cooperstein, S E; Awada, T

    2010-07-01

    Changes in climate, land management and fire regime have contributed to woody species expansion into grasslands and savannas worldwide. In the USA, Pinus ponderosa P.&C. Lawson and Juniperus virginiana L. are expanding into semiarid grasslands of Nebraska and other regions of the Great Plains. We examined P. ponderosa and J. virginiana seedling response to soil water content, one of the most important limiting factors in semiarid grasslands, to provide insight into their success in the region. Photosynthesis, stomatal conductance, maximum photochemical efficiency of PSII, maximum carboxylation velocity, maximum rate of electron transport, stomatal limitation to photosynthesis, water potential, root-to-shoot ratio, and needle nitrogen content were followed under gradual soil water depletion for 40 days. J. virginiana maintained lower L(s), higher A, g(s), and initial F(v)/F(m), and displayed a more gradual decline in V(cmax) and J(max) with increasing water deficit compared to P. ponderosa. J. virginiana also invested more in roots relative to shoots compared to P. ponderosa. F(v)/F(m) showed high PSII resistance to dehydration in both species. Photoinhibition was observed at approximately 30% of field capacity. Soil water content was a better predictor of A and g(s) than Psi, indicating that there are other growth factors controlling physiological processes under increased water stress. The two species followed different strategies to succeed in semiarid grasslands. P. ponderosa seedlings behaved like a drought-avoidant species with strong stomatal control, while J. virginiana was more of a drought-tolerant species, maintaining physiological activity at lower soil water content. Differences between the studied species and the ecological implications are discussed.

  6. The biophysical effects of deuterium oxide on biomolecules and living cells through open notebook science

    NASA Astrophysics Data System (ADS)

    Salvagno, Anthony L.

    This dissertation explores various effects of deuterium oxide (D2O also known as heavy water) in nature. Water is everywhere and interacts with just about everything. As such, it would be quite a daunting task to characterize every effect that water exhibits on everything in the universe. This research is a small piece of the puzzle, and provides some fundamental understanding of how water interacts with other molecules. This is done from two viewpoints: (1) the effects of heavy water on living cells and (2) the effects of heavy water on molecules. Varying concentrations of deuterium oxide were used as the growing solvent for four different organisms: S. cerevisiae, E. coli, A. thaliana, and N. tabacum. In each case growth rates and morphology was assessed and compared to the wild type. Organisms were surveyed for potential phenotypes exhibited in the presence of extremely low and high concentrations of D2O. In every organism, growth is increasingly inhibited in higher concentrations of D2O compared to lower concentrations of D2O. In the case of tobacco, a root hair phenotype was exhibited in the presence of deuterium depleted water (<1ppm deuterium atoms). Roots also grew faster in 1% D2O and DDW, compared to natural water. For Arabidopsis, root germination is statistically indistinguishable between DI water and 33% D2O. Growth of the plant in 10% D2O is identical to that of natural water, and potentially healthier. Meanwhile, plants grown in 60% D2O exhibit slower growth and leaf discoloration. Tests on E. coli reveal inconsistent growth rates, but exhibit increased growth in DDW when adapted to D2O. Cellular and colonial morphology is also very distinguished from the wt. Cells appear to remain joined after cellular fission, while colonies exhibit brainy structures. Yeast morphology is quite different. Yeast cells remain joined after mitosis in 99% D2O, causing large cellular aggregates, while colonies become slightly asymmetric. Adaptation of yeast to D2O was

  7. A hotspot analysis of the water footprint and groundwater depletion in the High Plains Aquifer

    NASA Astrophysics Data System (ADS)

    Multsch, Sebastian; Pahlow, Markus; Ellensohn, Judith; Michalik, Thomas; Frede, Hans-Georg; Breuer, Lutz

    2015-04-01

    The water footprint (WF) of irrigation agriculture sums up to 45.72 km3 yr-1(46% blue, 54% green) across the High Plains Aquifer (HPA) in the USA. Green WFs are dominating the north-east. Blue WFs are related to regions with intensive depletion of groundwater in the center and southern HPA, a situation further exacerbated by an increase of the blue water fraction of crop WF over the past (by 50% for 1990-1999; by 57% for 2000-2012). By means of a cluster analysis with the three parameter groundwater decline, blue and green WF, hotspots have been delineated spatially. Two sub-regions in the southern and central covering merely 20% of the HPA area have a share of one-third (7.92 km3 yr-1) of the total WF. This clearly shows that local strategies for sustainable allocation and use of freshwater resources are required. A likely impact of the sowing date (earliest vs. latest) on the WF has been studied, showing that blue WF increases by about 4% on average for all crops for the late sowing date, whereby the green and blue WF of cotton decreases totally about 0.9 km3 yr-1. Further evaluation criteria apart from water conservation considered are economic water productivity and nutritional value per volume of water consumed in agricultural production. Corn leads to the highest economic water productivity of 0.34 USD m-3, which in addition provides the highest nutritional value of 4362 kcal m-3. Favoring sorghum over corn was found advantageous in years with water shortage, because irrigation requirements and crop evapotranspiration of sorghum are lower by 20% and 25%, respectively, yet accompanied with nutritional losses of 28% compared to corn production. Such a trade-off is to be evaluated by farmers and policy makers, whereby the green and blue WFs, the impact of the sowing date as well as the economic and nutritional productivity presented here supports decision making.

  8. Modeling oxygen depletion forced by acetate discharge in the coastal waters of the North Sea

    NASA Astrophysics Data System (ADS)

    Ilinskaya, Alisa; Yakushev, Evgeny; Nøst, Ole-Anders; Pakhomova, Svetlana

    2017-04-01

    Consequences of discharge of acetate produced during the production of X-ray contrast agents in the coastal waters of the Norwegian coast of the North Sea were analyzed with a set of mathematical models. The baseline seasonal variability of temperature, salinity, advection and turbulence were calculated with the Finite Volume Community Ocean Model (FVCOM) applied to the Southern coast of Norway. These data were used to force a vertical 2-Dimensional Benthic-Pelagic transport model (2DBP) coupled via Framework for Aquatic Biogeochemical Models (FABM) with a biogeochemical model OxyDep, considering phytoplankton, heterotrophs, nutrient, dissolved organic matter, particulate organic matter, and dissolved oxygen (DO). Acetate was considered as a chemical oxygen depletion substrate leading to the decrease of oxygen concentrations. We simulated seasonal variability at a 10 km long vertical transect with a spatial resolution of 50 m horizontally and approximately 2 m vertically. These calculations reproduced local minimum in the vertical DO distributions in 2 km distance from the discharge point, that corresponded to the observations. We conducted numerical experiments on the effects of doubling of the acetate discharge and on formation of acetate complexes.

  9. 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.

  10. Determining water storage depletion within Iran by assimilating GRACE data into the W3RA hydrological model

    NASA Astrophysics Data System (ADS)

    Khaki, M.; Forootan, E.; Kuhn, M.; Awange, J.; van Dijk, A. I. J. M.; Schumacher, M.; Sharifi, M. A.

    2018-04-01

    Groundwater depletion, due to both unsustainable water use and a decrease in precipitation, has been reported in many parts of Iran. In order to analyze these changes during the recent decade, in this study, we assimilate Terrestrial Water Storage (TWS) data from the Gravity Recovery And Climate Experiment (GRACE) into the World-Wide Water Resources Assessment (W3RA) model. This assimilation improves model derived water storage simulations by introducing missing trends and correcting the amplitude and phase of seasonal water storage variations. The Ensemble Square-Root Filter (EnSRF) technique is applied, which showed stable performance in propagating errors during the assimilation period (2002-2012). Our focus is on sub-surface water storage changes including groundwater and soil moisture variations within six major drainage divisions covering the whole Iran including its eastern part (East), Caspian Sea, Centre, Sarakhs, Persian Gulf and Oman Sea, and Lake Urmia. Results indicate an average of -8.9 mm/year groundwater reduction within Iran during the period 2002 to 2012. A similar decrease is also observed in soil moisture storage especially after 2005. We further apply the canonical correlation analysis (CCA) technique to relate sub-surface water storage changes to climate (e.g., precipitation) and anthropogenic (e.g., farming) impacts. Results indicate an average correlation of 0.81 between rainfall and groundwater variations and also a large impact of anthropogenic activities (mainly for irrigations) on Iran's water storage depletions.

  11. Modeling the movement and equilibrium of water in the body of ruminants in relation to estimating body composition by deuterium oxide dilution

    SciTech Connect

    Arnold, R.N.

    1986-01-01

    Deuterium oxide (D/sub 2/O) dilution was evaluated for use in estimating body composition of ruminants. Empty body composition of cattle could not be accurately estimated by two- or three-compartment models when solved on the basis of clearance of D/sub 2/O from blood. A 29-compartment blood-flow model was developed from measured blood flow rates and water volumes of tissues of sheep. The rates of equilibration of water in tissues that were simulated by the blood-flow model were much faster than actual rates measured in sheep and cattle. The incorporation of diffusion hindrances for movement of water into tissues enabled the bloodmore » flow model to simulate the measured equilibration rates in tissues, but the values of the diffusion coefficients were different for each tissue. The D/sub 2/O-disappearance curve for blood simulated by the blood-flow model with diffusion limitations was comprised for four exponential components. The tissues and gastrointestinal tract contents were placed into five groups based upon the rate of equilibration. Water in the organs of the body equilibrated with water in blood within 3 min. Water in visceral fat, head, and some of the gastrointestinal tract tissues equilibrated within 8 to 16 min. Water in skeletal muscle, fat, and bone and the contents of some segments of the gastrointestinal tract equilibrated within 30 to 36 min. Water in the tissues and contents of the cecum and upper-large intestine equilibrated within 160 to 200 min. Water in ruminal tissue and contents equilibrated within 480 min.« less

  12. External reflection FTIR of peptide monolayer films in situ at the air/water interface: experimental design, spectra-structure correlations, and effects of hydrogen-deuterium exchange.

    PubMed Central

    Flach, C R; Brauner, J W; Taylor, J W; Baldwin, R C; Mendelsohn, R

    1994-01-01

    A Fourier transform infrared spectrometer has been interfaced with a surface balance and a new external reflection infrared sampling accessory, which permits the acquisition of spectra from protein monolayers in situ at the air/water interface. The accessory, a sample shuttle that permits the collection of spectra in alternating fashion from sample and background troughs, reduces interference from water vapor rotation-vibration bands in the amide I and amide II regions of protein spectra (1520-1690 cm-1) by nearly an order of magnitude. Residual interference from water vapor absorbance ranges from 50 to 200 microabsorbance units. The performance of the device is demonstrated through spectra of synthetic peptides designed to adopt alpha-helical, antiparallel beta-sheet, mixed beta-sheet/beta-turn, and unordered conformations at the air/water interface. The extent of exchange on the surface can be monitored from the relative intensities of the amide II and amide I modes. Hydrogen-deuterium exchange may lower the amide I frequency by as much as 11-12 cm-1 for helical secondary structures. This shifts the vibrational mode into a region normally associated with unordered structures and leads to uncertainties in the application of algorithms commonly used for determination of secondary structure from amide I contours of proteins in D2O solution. PMID:7919013

  13. Toward a better δDalkanes paleoclimate proxy; Partitioning of seasonal water sources and xylem-leaf deuterium enrichment according to plant growth form and phenology

    NASA Astrophysics Data System (ADS)

    Wispelaere, Lien; Bodé, Samuel; Herve-Fernández, Pedro; Hemp, Andreas; Verschuren, Dirk; Boeckx, Pascal

    2016-04-01

    deuterium enrichment, averaged over all plant species, sites and seasons equals 23 ± 27‰. Several factors influence the isotopic enrichment between xylem and leaf water, but according to our results, the growth form and phenology of plant species are the primary factors, while the location (proximity to the lake) and season exert relatively minor effects.

  14. Probing planetary interiors: Shock compression of water to 700 GPa and 3.8 g/cc, and recent high precision Hugoniot measurements of deuterium

    NASA Astrophysics Data System (ADS)

    Knudson, Marcus

    2013-06-01

    The past several years have seen tremendous increase in the number of identified extra-solar planetary systems. Our understanding of the formation of these systems is tied to our understanding of the internal structure of these exoplanets, which in turn rely upon equations of state of light elements and compounds such as water and hydrogen. Here we present shock compression data for water with unprecedented accuracy that shows commonly used models for water in planetary modeling significantly overestimate the compressibility at conditions relevant to planetary interiors. Furthermore, we show that its behavior at these conditions, including reflectivity and isentropic response, is well described by a recent first-principles based equation of state. These findings advocate the use of this model as the standard for modeling Neptune, Uranus, and ``hot Neptune'' exoplanets, and should contribute to improved understanding of the interior structure of these planets, and perhaps improved understanding of formation mechanisms of planetary systems. We also present very recent experiments on deuterium that have taken advantage of continued improvements in both experimental configuration and the understanding of the quartz shock standard to obtain Hugoniot data with a significant increase in precision. These data will prove to provide a stringent test for the equation of state of hydrogen and its isotopes. Sandia is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the US Department of Energy's National Nuclear Security Administration under Contract No. DE-ACO4-94AL85000.

  15. Impact of spatial variation in snow water equivalent and snow ablation on spring snowcover depletion over an alpine ridge

    NASA Astrophysics Data System (ADS)

    Schirmer, Michael; Harder, Phillip; Pomeroy, John

    2016-04-01

    The spatial and temporal dynamics of mountain snowmelt are controlled by the spatial distribution of snow accumulation and redistribution and the pattern of melt energy applied to this snowcover. In order to better quantify the spatial variations of accumulation and ablation, Structure-from-Motion techniques were applied to sequential aerial photographs of an alpine ridge in the Canadian Rocky Mountains taken from an Unmanned Aerial Vehicle (UAV). Seven spatial maps of snow depth and changes to depth during late melt (May-July) were generated at very high resolutions covering an area of 800 x 600 m. The accuracy was assessed with over 100 GPS measurements and RMSE were found to be less than 10 cm. Low resolution manual measurements of density permitted calculation of snow water equivalent (SWE) and change in SWE (ablation rate). The results indicate a highly variable initial SWE distribution, which was five times more variable than the spatial variation in ablation rate. Spatial variation in ablation rate was still substantial, with a factor of two difference between north and south aspects and small scale variations due to local dust deposition. However, the impact of spatial variations in ablation rate on the snowcover depletion curve could not be discerned. The reason for this is that only a weak spatial correlation developed between SWE and ablation rate. These findings suggest that despite substantial variations in ablation rate, snowcover depletion curve calculations should emphasize the spatial variation of initial SWE rather than the variation in ablation rate. While there is scientific evidence from other field studies that support this, there are also studies that suggest that spatial variations in ablation rate can influence snowcover depletion curves in complex terrain, particularly in early melt. The development of UAV photogrammetry has provided an opportunity for further detailed measurement of ablation rates, SWE and snowcover depletion over complex

  16. Benefits and Pitfalls of GRACE Data Assimilation: a Case Study of Terrestrial Water Storage Depletion in India

    PubMed Central

    Girotto, Manuela; De Lannoy, Gabriëlle J. M.; Reichle, Rolf H.; Rodell, Matthew; Draper, Clara; Bhanja, Soumendra N.; Mukherjee, Abhijit

    2018-01-01

    This study investigates some of the benefits and drawbacks of assimilating Terrestrial Water Storage (TWS) observations from the Gravity Recovery and Climate Experiment (GRACE) into a land surface model over India. GRACE observes TWS depletion associated with anthropogenic groundwater extraction in northwest India. The model, however, does not represent anthropogenic groundwater withdrawals and is not skillful in reproducing the interannual variability of groundwater. Assimilation of GRACE TWS introduces long-term trends and improves the interannual variability in groundwater. But the assimilation also introduces a negative trend in simulated evapotranspiration whereas in reality evapotranspiration is likely enhanced by irrigation, which is also unmodeled. Moreover, in situ measurements of shallow groundwater show no trend, suggesting that the trends are erroneously introduced by the assimilation into the modeled shallow groundwater, when in reality the groundwater is depleted in deeper aquifers. The results emphasize the importance of representing anthropogenic processes in land surface modeling and data assimilation systems. PMID:29643570

  17. Benefits and Pitfalls of GRACE Data Assimilation: a Case Study of Terrestrial Water Storage Depletion in India.

    PubMed

    Girotto, Manuela; De Lannoy, Gabriëlle J M; Reichle, Rolf H; Rodell, Matthew; Draper, Clara; Bhanja, Soumendra N; Mukherjee, Abhijit

    2017-05-16

    This study investigates some of the benefits and drawbacks of assimilating Terrestrial Water Storage (TWS) observations from the Gravity Recovery and Climate Experiment (GRACE) into a land surface model over India. GRACE observes TWS depletion associated with anthropogenic groundwater extraction in northwest India. The model, however, does not represent anthropogenic groundwater withdrawals and is not skillful in reproducing the interannual variability of groundwater. Assimilation of GRACE TWS introduces long-term trends and improves the interannual variability in groundwater. But the assimilation also introduces a negative trend in simulated evapotranspiration whereas in reality evapotranspiration is likely enhanced by irrigation, which is also unmodeled. Moreover, in situ measurements of shallow groundwater show no trend, suggesting that the trends are erroneously introduced by the assimilation into the modeled shallow groundwater, when in reality the groundwater is depleted in deeper aquifers. The results emphasize the importance of representing anthropogenic processes in land surface modeling and data assimilation systems.

  18. Benefits and Pitfalls of GRACE Data Assimilation: A Case Study of Terrestrial Water Storage Depletion in India

    NASA Technical Reports Server (NTRS)

    Girotto, Manuela; De Lannoy, Gabrielle J. M.; Reichle, Rolf H.; Rodell, Matthew; Draper, Clara S.; Bhanja, Soumendra N.; Mukherjee, Abhijit

    2017-01-01

    This study investigates some of the benefits and drawbacks of assimilating Terrestrial Water Storage (TWS) observations from the Gravity Recovery and Climate Experiment (GRACE) into a land surface model over India. GRACE observes TWS depletion associated with anthropogenic groundwater extraction in northwest India. The model, however, does not represent anthropogenic groundwater withdrawals and is not skillful in reproducing the interannual variability of groundwater. Assimilation of GRACE TWS introduces long-term trends and improves the interannual variability in groundwater. But the assimilation also introduces a negative trend in simulated evapotranspiration whereas in reality evapotranspiration is likely enhanced by irrigation, which is also unmodeled. Moreover, in situ measurements of shallow groundwater show no trend, suggesting that the trends are erroneously introduced by the assimilation into the modeled shallow groundwater, when in reality the groundwater is depleted in deeper aquifers. The results emphasize the importance of representing anthropogenic processes in land surface modeling and data assimilation systems.

  19. Soil water sensors for irrigation scheduling:Can they deliver a management allowed depletion?

    USDA-ARS?s Scientific Manuscript database

    Soil water sensors are widely marketed in the farming sector as aids for irrigation scheduling. Sensors report either volumetric water content (theta-v, m**3 m**-3) or soil water potential, with theta-v sensors being by far the most common. To obtain yield and quality goals, irrigations are schedule...

  20. 2H and 18O depletion of water close to organic surfaces

    NASA Astrophysics Data System (ADS)

    Chen, Guo; Auerswald, Karl; Schnyder, Hans

    2016-06-01

    Hydrophilic surfaces influence the structure of water close to them and may thus affect the isotope composition of water. Such an effect should be relevant and detectable for materials with large surface areas and low water contents. The relationship between the volumetric solid : water ratio and the isotopic fractionation between adsorbed water and unconfined water was investigated for the materials silage, hay, organic soil (litter), filter paper, cotton, casein and flour. Each of these materials was equilibrated via the gas phase with unconfined water of known isotopic composition to quantify the isotopic difference between adsorbed water and unconfined water. Across all materials, isotopic fractionation was significant (p<0.05) and negative (on average -0.91 ± 0.22 ‰ for 18/16O and -20.6 ± 2.4 ‰ for 2/1H at an average solid : water ratio of 0.9). The observed isotopic fractionation was not caused by solutes, volatiles or old water because the fractionation did not disappear for washed or oven-dried silage, the isotopic fractionation was also found in filter paper and cotton, and the fractionation was independent of the isotopic composition of the unconfined water. Isotopic fractionation became linearly more negative with increasing volumetric solid : water ratio and even exceeded -4 ‰ for 18/16O and -44 ‰ for 2/1H. This fractionation behaviour could be modelled by assuming two water layers: a thin layer that is in direct contact and influenced by the surface of the solid and a second layer of varying thickness depending on the total moisture content that is in equilibrium with the surrounding vapour. When we applied the model to soil water under grassland, the soil water extracted from 7 and 20 cm depth was significantly closer to local meteoric water than without correction for the surface effect. This study has major implications for the interpretation of the isotopic composition of water extracted from organic matter, especially when the volumetric

  1. Potential depletion of surface water in the Colorado River and agricultural drains by groundwater pumping in the Parker-Palo Verde-Cibola area, Arizona and California

    USGS Publications Warehouse

    Leake, Stanley A.; Owen-Joyce, Sandra J.; Heilman, Julian A.

    2013-01-01

    Water use along the lower Colorado River is allocated as “consumptive use,” which is defined to be the amount of water diverted from the river minus the amount that returns to the river. Diversions of water from the river include surface water in canals and water removed from the river by pumping wells in the aquifer connected to the river. A complication in accounting for water pumped by wells occurs if the pumping depletes water in drains and reduces measured return flow in those drains. In that case, consumptive use of water pumped by the wells is accounted for in the reduction of measured return flow. A method is needed to understand where groundwater pumping will deplete water in the river and where it will deplete water in drains. To provide a basis for future accounting for pumped groundwater in the Parker-Palo Verde-Cibola area, a superposition model was constructed. The model consists of three layers of finite-difference cells that cover most of the aquifer in the study area. The model was run repeatedly with each run having a pumping well in a different model cell. The source of pumped water that is depletion of the river, expressed as a fraction of the pumping rate, was computed for all active cells in model layer 1, and maps were constructed to understand where groundwater pumping depletes the river and where it depletes drains. The model results indicate that if one or more drains exist between a pumping well location and the river, nearly all of the depletion will be from drains, and little or no depletion will come from the Colorado River. Results also show that if a well pumps on a side of the river with no drains in the immediate area, depletion will come from the Colorado River. Finally, if a well pumps between the river and drains that parallel the river, a fraction of the pumping will come from the river and the rest will come from the drains. Model results presented in this report may be considered in development or refinement of strategies

  2. Averting a Disaster with Groundwater Depletion in India: The General Case of Water Management Principles and Development (Invited)

    NASA Astrophysics Data System (ADS)

    Lall, U.

    2013-12-01

    Many countries, including the USA, China, and India are experiencing chronic groundwater depletion. In part this unsustainable water use results from climatic factors that reduce surface water availability and also the recharge to the aquifer system. However, a more critical factor is uncontrolled use for agriculture and energy and mineral processing. Interestingly in places such as India endowments have been politically created that lead to ever increasing use, through the provision of free energy for pumping. Reversing the situation is considered politically challenging, and the concept of metering and payment for what is essentially economic use of water is also considered difficult to apply. In this talk I use the Indian situation as a general example and discuss the role central planning strategies for demand and resource management can play recognizing the private action by millions of users as an inevitable tool that needs to be leveraged without necessarily the high transaction costs that come with monitoring and fee collection for monitored use. Specifically, targeting and stimulating potential cropping strategies and on farm water and energy management emerge as a choice in a difficult management environment. In a broader development context, I argue that the role of private sector aggregators in developing farm to market procurement strategies can play a role in both improving rural economies and providing a trajectory for more efficient water use through technology and crop choice.

  3. Potential health implications of water resources depletion and sewage discharges in the Republic of Macedonia.

    PubMed

    Hristovski, Kiril D; Pacemska-Atanasova, Tatjana; Olson, Larry W; Markovski, Jasmina; Mitev, Trajce

    2016-08-01

    Potential health implications of deficient sanitation infrastructure and reduced surface water flows due to climate change are examined in the case study of the Republic of Macedonia. Changes in surface water flows and wastewater discharges over the period 1955-2013 were analyzed to assess potential future surface water contamination trends. Simple model predictions indicated a decline in surface water hydrology over the last half century, which caused the surface waters in Macedonia to be frequently dominated by >50% of untreated sewage discharges. The surface water quality deterioration is further supported by an increasing trend in modeled biochemical oxygen demand trends, which correspond well with the scarce and intermittent water quality data that are available. Facilitated by the climate change trends, the increasing number of severe weather events is already triggering flooding of the sewage-dominated rivers into urban and non-urban areas. If efforts to develop a comprehensive sewage collection and treatment infrastructure are not implemented, such events have the potential to increase public health risks and cause epidemics, as in the 2015 case of a tularemia outbreak.

  4. 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

  5. Depletion of Stem Water of Sclerocarya birrea Agroforestry Tree Precedes Start of Rainy Season in West African Sudanian Zone

    NASA Astrophysics Data System (ADS)

    Ceperley, Natalie; Mande, Theophile; Parlange, Marc B.

    2013-04-01

    Understanding water use by agroforestry trees in dry-land ecosystems is essential for improving water management. Agroforestry trees are valued and promoted for many of their ecologic and economic benefits but are often criticized as competing for valuable water resources. In order to understand the seasonal patterns of source water used by agroforestry trees, samples from rain, ground, and surface water were collected weekly in the subcatchment of the Singou watershed that is part of the Volta Basin. Soil and vegetation samples were collected from and under a Sclerocarya birrea agroforstry trees located in this catchment in sealed vials, extracted, and analyzed with a Picarro L2130-i CRDS to obtain both δO18 and δDH fractions. Meteorological measurements were taken with a network of wireless, autonomous stations that communicate through the GSM network (Sensorscope) and two complete eddy-covariance energy balance stations, in addition to intense monitoring of sub-canopy solar radiation, throughfall, stemflow, and soil moisture. Examination of the time series of δO18 concentrations confirm that values in soil and xylem water are coupled, both becoming enriched during the dry season and depleted during the rainy season. Xylem water δO18 levels drops to groundwater δO18 levels in early March when trees access groundwater for leafing out, however soil water does not reach this level until soil moisture increases in mid-June. The relationship between the δDH and δO18 concentrations of water extracted from soil and tree samples do not fall along the global meteoric water line. In order to explore whether this was a seasonally driven, we grouped samples into an "evaporated" group or a "meteoric" group based on the smaller residual to the respective lines. Although more soil samples were found along the m-line during the rainy season than tree samples or dry season soil samples, there was no significant difference in days since rain for any group This suggests that

  6. The Deuterium to Hydrogen Ratio in the Water that Formed the Yellowknife Bay Mudstones in Gale Crater

    NASA Technical Reports Server (NTRS)

    Mahaffy, Paul R.; Brunner, Anna E.; Webster, Chris R.; Atreya, Sushil K.; Mcadam, Amy Catherine; Stern, Jennifer Claire; Leshin, Laurie Ann; Navarro-Gonzales, Rafael; Jones, J.; Kashyap, Srishti

    2014-01-01

    A suite of isotope ratios of light elements in the present martian atmosphere (13C/12C, 15N/14N, 18O/16O, 38Ar/36Ar, and D/H) are all substantially enriched in the heavy element suggesting atmospheric loss to space over the past billions of years with preferential loss of the lighter isotope from each pair. In situ measurements from MSL's Sample Analysis at Mars (SAM) instrument [e.g. 1,2,3] have considerably refined previous measurements from the Viking mass spectrometers [e.g. 4], from remote spectroscopic observations [e.g. 5,6], and from martian meteorite studies [e.g. 7,8]. The persistence of habitable environments such as the ancient Yellowknife Bay lake recently revealed by measurements from the Curiosity rover [9] depends on the surface temperatures and the duration of an atmosphere thicker than that at present. Current and planned measurements from orbit with the Mars Express and MAVEN missions respectively intend to study the processes of atmospheric escape including solar wind interaction, sputtering, thermal escape, and dissociative recombination, and determine or refine the current rate of atmospheric loss caused by these and other mechanisms. The goal of these programs is to understand the physical processes sufficiently well so that robust extrapolations over the past billions of years can be made D/H is measured by both the Tunable Laser Spectrometer (TLS) and the Quadrupole Mass Spectrometer (QMS) of the SAM suite. to predict the atmospheric and surface conditions on early Mars. However, the study of the history of martian atmospheric evolution will be greatly facilitated if we are able to also directly measure the isotopic composition of volatiles captured in rocks that are representative of the ancient atmosphere. To date, D/H is one of the most promising candidates for this study since water is the most abundant volatile thermally released from the Yellowknife Bay phylosilicates discovered by the SAM and CheMin experiments of MSL and its

  7. Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion.

    PubMed

    Bernacchi, Carl J; Leakey, Andrew D B; Kimball, Bruce A; Ort, Donald R

    2011-06-01

    Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O₃]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O₃] on crop ecosystem energy fluxes and water use. Elevated [O₃] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 °C. Published by Elsevier Ltd.

  8. Deuterium microbomb rocket propulsion

    NASA Astrophysics Data System (ADS)

    Winterberg, F.

    2010-01-01

    Large scale manned space flight within the solar system is still confronted with the solution of two problems: (1) A propulsion system to transport large payloads with short transit times between different planetary orbits. (2) A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed where a thermonuclear detonation wave is ignited in a small cylindrical assembly of deuterium with a gigavolt-multimegaampere proton beam, drawn from the magnetically insulated spacecraft acting in the ultrahigh vacuum of space as a gigavolt capacitor. For the solution of the second problem, the ignition is done by argon ion lasers driven by high explosives, with the lasers destroyed in the fusion explosion and becoming part of the exhaust.

  9. Groundwater depletion in Central Mexico: Use of GRACE and InSAR to support water resources management

    NASA Astrophysics Data System (ADS)

    Castellazzi, Pascal; Martel, Richard; Rivera, Alfonso; Huang, Jianliang; Pavlic, Goran; Calderhead, Angus I.; Chaussard, Estelle; Garfias, Jaime; Salas, Javier

    2016-08-01

    Groundwater deficits occur in several areas of Central Mexico, where water resource assessment is limited by the availability and reliability of field data. In this context, GRACE and InSAR are used to remotely assess groundwater storage loss in one of Mexico's most important watersheds in terms of size and economic activity: the Lerma-Santiago-Pacifico (LSP). In situ data and Land Surface Models are used to subtract soil moisture and surface water storage changes from the total water storage change measured by GRACE satellites. As a result, groundwater mass change time-series are obtained for a 12 years period. ALOS-PALSAR images acquired from 2007 to 2011 were processed using the SBAS-InSAR algorithm to reveal areas subject to ground motion related to groundwater over-exploitation. In the perspective of providing guidance for groundwater management, GRACE and InSAR observations are compared with official water budgets and field observations. InSAR-derived subsidence mapping generally agrees well with official water budgets, and shows that deficits occur mainly in cities and irrigated agricultural areas. GRACE does not entirely detect the significant groundwater losses largely reported by official water budgets, literature and InSAR observations. The difference is interpreted as returns of wastewater to the groundwater flow systems, which limits the watershed scale groundwater depletion but suggests major impacts on groundwater quality. This phenomenon is enhanced by ground fracturing as noticed in the field. Studying the fate of the extracted groundwater is essential when comparing GRACE data with higher resolution observations, and particularly in the perspective of further InSAR/GRACE combination in hydrogeology.

  10. Coastal Upwelling Supplies Oxygen-Depleted Water to the Columbia River Estuary

    PubMed Central

    Roegner, G. Curtis; Needoba, Joseph A.; Baptista, António M.

    2011-01-01

    Low dissolved oxygen (DO) is a common feature of many estuarine and shallow-water environments, and is often attributed to anthropogenic nutrient enrichment from terrestrial-fluvial pathways. However, recent events in the U.S. Pacific Northwest have highlighted that wind-forced upwelling can cause naturally occurring low DO water to move onto the continental shelf, leading to mortalities of benthic fish and invertebrates. Coastal estuaries in the Pacific Northwest are strongly linked to ocean forcings, and here we report observations on the spatial and temporal patterns of oxygen concentration in the Columbia River estuary. Hydrographic measurements were made from transect (spatial survey) or anchor station (temporal survey) deployments over a variety of wind stresses and tidal states during the upwelling seasons of 2006 through 2008. During this period, biologically stressful levels of dissolved oxygen were observed to enter the Columbia River estuary from oceanic sources, with minimum values close to the hypoxic threshold of 2.0 mg L−1. Riverine water was consistently normoxic. Upwelling wind stress controlled the timing and magnitude of low DO events, while tidal-modulated estuarine circulation patterns influenced the spatial extent and duration of exposure to low DO water. Strong upwelling during neap tides produced the largest impact on the estuary. The observed oxygen concentrations likely had deleterious behavioral and physiological consequences for migrating juvenile salmon and benthic crabs. Based on a wind-forced supply mechanism, low DO events are probably common to the Columbia River and other regional estuaries and if conditions on the shelf deteriorate further, as observations and models predict, Pacific Northwest estuarine habitats could experience a decrease in environmental quality. PMID:21533083

  11. Distribution and flux estimates of soluble, colloidal, and leachable particulate trace metals in dynamic and oxygen depleted Mauritanian shelf waters

    NASA Astrophysics Data System (ADS)

    Rapp, I.; Schlosser, C.; Gledhill, M.; Achterberg, E. P.

    2016-02-01

    Fe availability in surface waters determines primary production, N2 fixation and microbial community structure and thus plays an important role in ocean carbon and nitrogen cycles. Eastern boundary upwelling areas with oxygen minimum zones, such as the Mauritanian shelf region, are typically associated with elevated Fe concentrations with shelf sediments as key source of Fe to bottom and surface waters. The magnitude of vertical and horizontal Fe fluxes from shelf sediments to onshore and offshore surface waters are not well constrained and there are still large uncertainties concerning the stabilisation of Fe once released from sediments into suboxic and oxic waters. Supportive data of other trace metals can be used as an indicator of sediment release, scavenging processes and biological utilisation. Here we present soluble (<0.02 µm), dissolved (<0.2 µm) and total dissolvable (unfiltered) trace metal data collected at 10 stations on a 90 nautical mile transect across the Mauritanian shelf region in June 2014 (cruise Meteor 107). The samples were pre-concentrated using an automated off-line pre-concentration device and analysed simultaneously for Cd, Pb, Fe, Ni, Cu, Zn, Mn and Co using a high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS). First results indicate the importance of benthic sources to the overall Fe budget in this region. Both dissolved Fe and Mn showed enhanced concentrations close to the shelf at depths between 40 and 180 m corresponding with low oxygen concentrations (<50 µmol L-1). Elevated soluble, dissolved, and total dissolvable Fe and Mn concentrations at an offshore station coincided with the location of a cyclonic Eddie that was characterised by an oxygen depleted water body. To further assess the accuracy of vertical and horizontal fluxes of Fe and other trace metals, we compare diffusivity estimates determined by a microstructure profiler and the scale length method (de Jong et al. 2012) with observed isotopic Ra

  12. 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.

  13. Water, Methane Depletion, and High-Altitude Condensates in the Atmosphere of the Warm Super-Neptune WASP-107b

    NASA Astrophysics Data System (ADS)

    Kreidberg, Laura; Line, Michael; Thorngren, Daniel; Morley, Caroline; Stevenson, Kevin

    2018-01-01

    The super-Neptune exoplanet WASP-107b is an exciting target for atmosphere characterization. It has an unusually large atmospheric scale height and a small, bright host star, raising the possibility of precise constraints on its current nature and formation history. In this talk, I will present the first atmospheric study of WASP-107b, a Hubble Space Telescope measurement of its near-infrared transmission spectrum. We determined the planet's composition with two techniques: atmospheric retrieval based on the transmission spectrum and interior structure modeling based on the observed mass and radius. The interior structure models set a 3σ upper limit on the atmospheric metallicity of 30x solar. The transmission spectrum shows strong evidence for water absorption (6.5σ confidence), and we infer a water abundance consistent with expectations for a solar abundance pattern. On the other hand, methane is depleted relative to expectations (at 3σ confidence), suggesting a low carbon-to-oxygen ratio or high internal heat flux. The water features are smaller than predicted for a cloudless atmosphere, crossing less than one scale height. A thick condensate layer at high altitudes (0.1 - 3 mbar) is needed to match the observations; however, we find that it is challenging for physically motivated cloud and haze models to produce opaque condensates at these pressures. Taken together, these findings serve as an illustration of the diversity and complexity of exoplanet atmospheres. The community can look forward to more such results with the high precision and wide spectral coverage afforded by future observing facilities.

  14. Dissolved-oxygen depletion and other effects of storing water in Flaming Gorge Reservoir, Wyoming and Utah

    USGS Publications Warehouse

    Bolke, E.L.

    1979-01-01

    The circulation of water in Flaming Gorge Reservoir is caused chiefly by insolation, inflow-outflow relationships, and wind, which is significant due to the geographical location of the reservoir. During 1970-75, there was little annual variation in the thickness, dissolved oxygen, and specific conductance of the hypolimnion near Flaming Gorge Dam. Depletion of dissolved oxygen occurred simultaneously in the bottom waters of both tributary arms in the upstream part of the reservoir and was due to reservoir stratification. Anaerobic conditions in the bottom water during summer stratification eventually results in a metalimnetic oxygen minimum in the reservoir.The depletion of flow in the river below Flaming Gorge Dam due to evaporation and bank storage in the reservoir for the 1963-75 period was 1,320 cubic hectometers, and the increase of dissolved-solids load in the river was 1,947,000 metric tons. The largest annual variations in dissolved-solids concentration in the river was about 600 milligrams per liter before closure of the dam and about 200 milligrams per liter after closure. The discharge weighted-average dissolved-solids concentration for the 5 years prior to closure was 386 milligrams per liter and 512 milligrams per liter after closure. The most significant changes in the individual dissolved-ion loads in the river during 1973-75 were the increase in sulfate (0.46 million metric tons), which was probably derived from the solution of gypsum, and the decrease in bicarbonate (0.39 million metric tons), which can be attributed to chemical precipitation.The maximum range in temperature in the Green River below the reservoir prior to closure of the dam in 1962 was from 0°C in winter to 21°C in summer. After closure until 1970 the temperature ranged from 2° to 12°C, but since 1970 the range has been from 4° to 9°C.The maximum range in temperature in the Green River below the reservoir prior to closure of the dam in 1962 was from 0°C in winter to 21

  15. Concentration and characteristics of depleted uranium in water, air and biological samples collected in Serbia and Montenegro.

    PubMed

    Jia, Guogang; Belli, Maria; Sansone, Umberto; Rosamilia, Silvia; Gaudino, Stefania

    2005-09-01

    During the Balkan conflicts, in 1995 and 1999, depleted uranium (DU) rounds were employed and were left in the battlefield. Health concern is related to the risk arising from contamination of the environment with DU penetrators and dust. In order to evaluate the impact of DU on the environment and population in Serbia and Montenegro, radiological surveys of DU in water, air and biological samples were carried out over the period 27 October-5 November 2001. The uranium isotopic concentrations in biological samples collected in Serbia and Montenegro, mainly lichens and barks, were found to be in the range of 0.67-704 Bqkg(-1) for (238)U, 0.48-93.9 Bqkg(-1) for (234)U and 0.02-12.2 Bqkg(-1) for (235)U, showing uranium levels to be higher than in the samples collected at the control sites. Moreover, (236)U was detectable in some of the samples. The isotopic ratios of (234)U/(238)U showed DU to be detectable in many biological samples at all examined sites, especially in Montenegro, indicating widespread ground-surface DU contamination, albeit at very low level. The uranium isotopic concentrations in air obtained from the air filter samples collected in Serbia and Montenegro were found to be in the range of 1.99-42.1 microBqm(-3) for (238)U, 0.96-38.0 microBqm(-3) for (234)U, and 0.05-1.83 microBqm(-3) for (235)U, being in the typical range of natural uranium values. Thus said, most of the air samples are DU positive, this fact agreeing well with the widespread DU contamination detected in the biological samples. The uranium concentrations in water samples collected in Serbia and Montenegro were found to be in the range of 0.40-21.9 mBql(-1) for (238)U, 0.27-28.1 mBql(-1) for (234)U, and 0.01-0.88 mBql(-1) for (235)U, these values being much lower than those in mineral water found in central Italy and below the WHO guideline for drinking water. From a radiotoxicological point of view, at this moment there is no significant radiological risk related to these investigated

  16. Ozone treatment and the depletion of detectable pharmaceuticals and atrazine herbicide in drinking water sourced from the upper Detroit River, Ontario, Canada.

    PubMed

    Hua, Wenyi; Bennett, Erin R; Letcher, Robert J

    2006-07-01

    The depletion and degradation of pharmacologically active compounds (PhACs) and pesticides as a function of ozonation in drinking water treatment processes is not well studied. The A.H. Weeks drinking water treatment plant (DWTP) serves the City of Windsor, Ontario Canada, and incorporates ozone treatment into the production of drinking water. This DWTP also operates a real-time, scaled down pilot plant, which has two parallel streams, conventional and ozone plus conventional treatments. In this study water samples were collected from key points in the two streams of the pilot plant system to determine the depletion and influence of seasonal changes in water processing parameters on eighteen major PhACs (and metabolites) and seven s-triazines herbicides. However, only carbamazepine (antiepileptic), caffeine (stimulant), cotinine (metabolite of nicotine) and atrazine were consistently detectable in the raw water intake (low to sub-ng/L level). Regardless of the seasonality, the flocculation-coagulation and dual media filtration steps without ozone treatment resulted in no decrease in analyte concentrations, while decreases of 66-100% (undetectable, method detection limits 0.05-1 ng/L) of the analyte concentrations were observed when ozone treatment was part of the water processing. These findings demonstrate that ozone treatment is highly effective in depleting carbamazepine, caffeine, cotinine, and atrazine, and thus is highly influential in the fate of these compounds in drinking water treatment regardless of the seasonal time frame. Currently very few Canadian DWTPs incorporate ozonation into conventional treatment, which suggests that human exposure to these compounds via drinking water consumption may be an issue in affected communities.

  17. PHYSIOLOGICAL EFFECTS OF DEUTERIUM ON DOGS

    SciTech Connect

    Czajka, D.M.; Finkel, A.J.; Fischer, C.S.

    1961-08-01

    The physiological consequences of the deuterium isotope effect in lange mammals were studied in two dogs, one of which was maintained at 20% concentration of D/sub 2/0 in the bcdy fluids for 50 days, and the other at the toxic range of 33-35% for a brief pericd. Deuteration of the dcgs was effected by replacement of ordinary water with deuterium oxide in both focd and drink. Hemoglobin, hematocrit, and red blood cell count dropped but the white blood cell count was essentially unaffected although there was a progressive lymphopenia and granulocytosis. Serum glucose was decreased, especially at higher deuterium levels.more » Total serum cholesterol values were also diminished although the esters were essentially unchanged. Serum sodium and both NPN and BUN were within normal limits except for a terminal elevation of the latter. Serum potassium was slightly lowered for a brief period after 3 weeks. Electrocardiograms showed ST segment coving and elevation and an increase in the QT ratio that suggested nonspecific myocardial damage; these changes reverted to normal while the dog was still deuterated at a level of 20%. Both dogs exhibited neuromuscular disturbances, in one case definite weakness of the hind legs and in the other, fine muscle tremors. (auth)« less

  18. Physicochemical Processes on Ice Dust Towards Deuterium Enrichment

    NASA Astrophysics Data System (ADS)

    Watanabe, Naoki

    2017-06-01

    Water and some organic molecules were found to be deuterium enriched toward various astronomical targets. Understanding the deuterium-fractionation process pertains directly to know how and when molecules are created. Although gas phase chemistry is certainly important for deuterium enrichment, the role of physicochemical processes on the dust surfaces should be also considered. In fact, the extreme deuterium enrichment of formaldehyde and methanol requires the dust grain-surface process. In this context, we have performed a series of experiments on the formation of deuterated species of water and simple organic molecules. From the results of these experiments and related works, I will discuss the key processes for the deuterium enrichment on dust. For deuterium chemistry, another important issue is the ortho-to-para ratio (OPR) of H_{2}, which is closely related to the formation of H_{2}D^{+} and thus the deuterium fractionation of molecules in the gas phase. Because the radiative nuclear spin conversion of H_{2} is forbidden, the ortho-para conversion is very slow in the gas phase. In contrast, it was not obvious how the nuclear spins behave on cosmic dust. Therefore, it is desirable to understand how the OPR of H_{2} is determined on the dust surfaces. We have tackled this issue experimentally. Using experimental techniques of molecular beam, photostimulated-desorption, and resonance-enhanced multiphoton ionization, we measured the OPRs of H_{2} photodesorbed from amorphous solid water at around 10 K, which is an ice dust analogue. It was first demonstrated that the rate of spin conversion from ortho to para drastically increases from 2.4 × 10^{-4} to 1.7 × 10^{-3} s^{-1} within the very narrow temperature window of 9.2 to16 K. The observed strong temperature cannot be explained by solely state-mixing models ever proposed but by the energy dissipation model via two phonon process. I will present our recent experiments regarding this.

  19. A Reexamination of Deuterium Fractionation on Mars

    NASA Astrophysics Data System (ADS)

    Pathare, A.; Paige, D. A.

    1997-07-01

    The ratio of deuterium to hydrogen in the Martian atmosphere is enhanced by a factor of 5 with respect to the terrestrial value, probably due to fractionation associated with thermal Jeans escape from the top of the atmosphere. Theoretical analyses of the relative efficiency of H and D escape have suggested that the deuterium enrichment implies Mars has outgassed the vast majority of its H2O and that the Martian atmosphere is presently not exchanging water with a juvenile reservoir. However, measurements of high and variable D/H values within hydrous minerals in SNC meteorites strongly suggest that mixing between the atmosphere and juvenile water has taken place. Furthermore, the lack of any observed enrichment of atmospheric (18) O with respect to (16) O, in spite of fractionating nonthermal escape mechanisms, indicates buffering by some juvenile source of oxygen, most probably in the form of a surface or subsurface reservoir of water. We propose that this apparent paradox in the interpretation of isotopic hydrogen and oxygen fractionation --or lack thereof-- can be resolved by re-examining the standard model of deuterium fractionation efficiency on Mars. Specifically, we demonstrate the importance of using upper atmospheric temperatures more representative of the range experienced by the Martian exosphere over the course of the solar cycle. Preliminary calculations involving changes in effusion velocity and diffusive separation as a function of exospheric temperature indicate that incorporating these more representative lower exospheric temperatures will reduce the relative efficiency of D escape, in which case the observed enrichment of deuterium can indeed result from exchange with a juvenile source of water. We are in the process of confirming these computations with a one-dimensional upper atmospheric photochemical model that considers the effects of changing solar activity and exospheric temperature on ionospheric composition. If our initial calculations are

  20. Characterization of a deuterium-deuterium plasma fusion neutron generator

    NASA Astrophysics Data System (ADS)

    Lang, R. F.; Pienaar, J.; Hogenbirk, E.; Masson, D.; Nolte, R.; Zimbal, A.; Röttger, S.; Benabderrahmane, M. L.; Bruno, G.

    2018-01-01

    We characterize the neutron output of a deuterium-deuterium plasma fusion neutron generator, model 35-DD-W-S, manufactured by NSD/Gradel-Fusion. The measured energy spectrum is found to be dominated by neutron peaks at 2.2 MeV and 2.7 MeV. A detailed GEANT4 simulation accurately reproduces the measured energy spectrum and confirms our understanding of the fusion process in this generator. Additionally, a contribution of 14 . 1 MeV neutrons from deuterium-tritium fusion is found at a level of 3 . 5%, from tritium produced in previous deuterium-deuterium reactions. We have measured both the absolute neutron flux as well as its relative variation on the operational parameters of the generator. We find the flux to be proportional to voltage V 3 . 32 ± 0 . 14 and current I 0 . 97 ± 0 . 01. Further, we have measured the angular dependence of the neutron emission with respect to the polar angle. We conclude that it is well described by isotropic production of neutrons within the cathode field cage.

  1. 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%.

  2. Assessment of groundwater/surface-water interaction and simulation of potential streamflow depletion induced by groundwater withdrawal, Uinta River near Roosevelt, Utah

    USGS Publications Warehouse

    Lambert, P.M.; Marston, T.; Kimball, B.A.; Stolp, B.J.

    2011-01-01

    Roosevelt City, Utah, asserts a need for an additional supply of water to meet municipal demands and has identified a potential location for additional groundwater development at the Sprouse well field near the West Channel of the Uinta River. Groundwater is commonly hydraulically linked to surface water and, under some conditions, the pumpage of groundwater can deplete water in streams and other water bodies. In 2008, the U.S. Geological Survey, in cooperation with Roosevelt City, the Utah Department of Natural Resources, and the Ute Indian Tribe, began a study to improve understanding of the local interconnection between groundwater and surface water and to assess the potential for streamflow depletion from future groundwater withdrawals at a potential Roosevelt City development location—the Sprouse well field near the West Channel of the Uinta River.In the study, streamflow gains and losses at the river/aquifer boundary near the well field and changes in those conditions over time were assessed through (1) synoptic measurement of discharge in the stream at multiple sites using tracer-dilution methods, (2) periodic measurement of the vertical hydraulic gradient across the streambed, and (3) continuous measurement of stream and streambed water temperature using heat as a tracer of flow across the streambed. Although some contradictions among the results of the three assessment methods were observed, results of the approaches generally indicated (1) losing streamflow conditions on the West Channel of the Uinta River north of and upstream from the Sprouse well field within the study area, (2) gaining streamflow conditions south of and downstream from the well field, and (3) some seasonal changes in those conditions that correspond with seasonal changes in stream stage and local water-table altitudes.A numerical groundwater flow model was developed on the basis of previously reported observations and observations made during this study, and was used to estimate

  3. 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...

  4. SODIUM DEUTERIUM REACTOR

    DOEpatents

    Oppenheimer, E.D.; Weisberg, R.A.

    1963-02-26

    This patent relates to a barrier system for a sodium heavy water reactor capable of insuring absolute separation of the metal and water. Relatively cold D/sub 2/O moderator and reflector is contained in a calandria into which is immersed the fuel containing tubes. The fuel elements are cooled by the sodium which flows within the tubes and surrounds the fuel elements. The fuel containing tubes are surrounded by concentric barrier tubes forming annular spaces through which pass inert gases at substantially atmospheric pressure. Header rooms above and below the calandria are provided for supplying and withdrawing the sodium and inert gases in the calandria region. (AEC)

  5. Sudden clearing of estuarine waters upon crossing the threshold from transport to supply regulation of sediment transport as an erodible sediment pool is depleted: San Francisco Bay, 1999

    USGS Publications Warehouse

    Schoellhamer, David H.

    2011-01-01

    The quantity of suspended sediment in an estuary is regulated either by transport, where energy or time needed to suspend sediment is limiting, or by supply, where the quantity of erodible sediment is limiting. This paper presents a hypothesis that suspended-sediment concentration (SSC) in estuaries can suddenly decrease when the threshold from transport to supply regulation is crossed as an erodible sediment pool is depleted. This study was motivated by a statistically significant 36% step decrease in SSC in San Francisco Bay from water years 1991–1998 to 1999–2007. A quantitative conceptual model of an estuary with an erodible sediment pool and transport or supply regulation of sediment transport is developed. Model results confirm that, if the regulation threshold was crossed in 1999, SSC would decrease rapidly after water year 1999 as observed. Estuaries with a similar history of a depositional sediment pulse followed by erosion may experience sudden clearing.

  6. Effect of changes in the deuterium content of drinking water on the hydrogen isotope ratio of urinary steroids in the context of sports drug testing.

    PubMed

    Piper, Thomas; Degenhardt, Karoline; Federherr, Eugen; Thomas, Andreas; Thevis, Mario; Saugy, Martial

    2013-03-01

    The hydrogen isotope ratio (HIR) of body water and, therefore, of all endogenously synthesized compounds in humans, is mainly affected by the HIR of ingested drinking water. As a consequence, the entire organism and all of its synthesized substrates will reflect alterations in the isotope ratio of drinking water, which depends on the duration of exposure. To investigate the effect of this change on endogenous urinary steroids relevant to doping-control analysis the hydrogen isotope composition of potable water was suddenly enriched from -50 to 200 ‰ and maintained at this level for two weeks for two individuals. The steroids under investigation were 5β-pregnane-3α,20α-diol, 5α-androst-16-en-3α-ol, 3α-hydroxy-5α-androstan-17-one (ANDRO), 3α-hydroxy-5β-androstan-17-one (ETIO), 5α-androstane-3α,17β-diol, and 5β-androstane-3α,17β-diol (excreted as glucuronides) and ETIO, ANDRO and 3β-hydroxyandrost-5-en-17-one (excreted as sulfates). The HIR of body water was estimated by determination of the HIR of total native urine, to trace the induced changes. The hydrogen in steroids is partly derived from the total amount of body water and cholesterol-enrichment could be calculated by use of these data. Although the sum of changes in the isotopic composition of body water was 150 ‰, shifts of approximately 30 ‰ were observed for urinary steroids. Parallel enrichment in their HIR was observed for most of the steroids, and none of the differences between the HIR of individual steroids was elevated beyond recently established thresholds. This finding is important to sports drug testing because it supports the intended use of this novel and complementary methodology even in cases where athletes have drunk water of different HIR, a plausible and, presumably, inevitable scenario while traveling.

  7. Co-adsorption of water and oxygen on GaN: Effects of charge transfer and formation of electron depletion layer.

    PubMed

    Wang, Qi; Puntambekar, Ajinkya; Chakrapani, Vidhya

    2017-09-14

    Species from ambient atmosphere such as water and oxygen are known to affect electronic and optical properties of GaN, but the underlying mechanism is not clearly known. In this work, we show through careful measurement of electrical resistivity and photoluminescence intensity under various adsorbates that the presence of oxygen or water vapor alone is not sufficient to induce electron transfer to these species. Rather, the presence of both water and oxygen is necessary to induce electron transfer from GaN that leads to the formation of an electron depletion region on the surface. Exposure to acidic gases decreases n-type conductivity due to increased electron transfer from GaN, while basic gases increase n-type conductivity and PL intensity due to reduced charge transfer from GaN. These changes in the electrical and optical properties, as explained using a new electrochemical framework based on the phenomenon of surface transfer doping, suggest that gases interact with the semiconductor surface through electrochemical reactions occurring in an adsorbed water layer present on the surface.

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

    PubMed

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

  9. THE FORMATION OF DETONATION IN SATURATED MIXTURES OF KNALLGAS-STEAM AND IN STOICHIOMETRIC MIXTURES OF DEUTERIUM-OXYGEN (HEAVY WATER). Final Report

    SciTech Connect

    Luker, J.A.; Adler, L.B.; Hobaica, E.C.

    1959-01-23

    The purpose of this investigation was to determine the reaction characteristics of satuated mixtures of knall gas (stoichiometric mixture of hydrogen and oxygen) --steam and mixtures of heavy knall gas (stoichm-ometric mixture of deuterion and oxygen) saturated with heavy water. These mixtues were studied experimentally over composition ranges from no reaction limit to enriched compositions which supported detonations. (auth)

  10. Patterns of mortality among South Florida Manatees: Evidence from oxygen, sulfur and deuterium stable isotopes

    NASA Astrophysics Data System (ADS)

    MacAvoy, S. E.; Bacalan, V.; Kazantseva, M.; Rhodes, J.; Kim, K.

    2012-12-01

    The Florida manatee (Trichechus manatus latirostris) is an endangered marine mammal whose coastal habitat has been heavily altered by human development. Sources of mortality include anthropogenic and environmental causes. Necropsies were completed on 75 deceased individuals, and tissues, including bone samples, were collected for later analysis. This study investigates the utility of manatee bone stable oxygen (δ18O), sulfur (δ34S) and deuterium (δD) for determining where the animals lived (which may not be where they where their bodies were recovered), and the relative importance of marine versus freshwater for the individual animals. The isotopes can provide a "geochemical map" showing the distribution of mortality, aiding in the evaluation of geographical patterns in mortality. The δ18O signatures of the bones ranged from 14 to 18.5‰, with no significant difference between male and female mean values. δ18O significantly decreased with increasing latitude (p=.0016), a trend positively correlated with coastal Florida seawater δ18O literature values obtained from the NASA Global Seawater Oxygen-18 Database (http://data.giss.nasa.gov/o18data/) and the EAIA stable isotope database (http://www.univie.ac.at/cartography/project/wiser/). Bone δ34S indicated the influence of marine versus coastal freshwater dietary sources on the animals. Most individuals showed 34S-depleted signatures, which indicated a non-marine sulfur source; however some individuals clearly had taken up marine sulfate (mean 4.9 ± 3.7‰, range 0.8 to 13.8‰). Deuterium values were not available at the time this abstract was written, however we hypothesize that those values will co-vary with δ18O. We conclude that manatee diets are based on both marine and freshwater sources, but freshwater sources exert more influence. Marine water and manatee δ18O co-vary with latitude, suggesting that stable oxygen isotopes may be useful indicators of the latitude where manatees lived.

  11. Using Gridded Snow Covered Area and Snow-Water Equivalence Spatial Data Sets to Improve Snow-Pack Depletion Simulation in a Continental Scale Hydrologic Model

    NASA Astrophysics Data System (ADS)

    Risley, J. C.; Tracey, J. A.; Markstrom, S. L.; Hay, L.

    2014-12-01

    Snow cover areal depletion curves were used in a continuous daily hydrologic model to simulate seasonal spring snowmelt during the period between maximum snowpack accumulation and total melt. The curves are defined as the ratio of snow-water equivalence (SWE) divided by the seasonal maximum snow-water equivalence (Ai) (Y axis) versus the percent snow cover area (SCA) (X axis). The slope of the curve can vary depending on local watershed conditions. Windy sparsely vegetated high elevation watersheds, for example, can have a steeper slope than lower elevation forested watersheds. To improve the accuracy of simulated runoff at ungaged watersheds, individual snow cover areal depletion curves were created for over 100,000 hydrologic response units (HRU) in the continental scale U.S. Geological Survey (USGS) National Hydrologic Model (NHM). NHM includes the same components of the USGS Precipitation-Runoff-Modeling System (PRMS), except it uses consistent land surface characterization and model parameterization across the U.S. continent. Weighted-mean daily time series of 1-kilometer gridded SWE, from Snow Data Assimilation System (SNODAS), and 500-meter gridded SCA, from Moderate Resolution Imaging Spectroradiometer (MODIS), for 2003-2014 were computed for each HRU using the USGS Geo Data Portal. Using a screening process, pairs of SWE/Ai and SCA from the snowmelt period of each year were selected. SCA values derived from imagery that did not have any cloud cover and were >0 and <100 percent were selected. Unrealistically low and high SCA values that were paired with high and low SWE/Ai ratios, respectively, were removed. Second order polynomial equations were then fit to the remaining pairs of SWE/Ai and SCA to create a unique curve for each HRU. Simulations comparing these new curves with an existing single default curve in NHM will be made to determine if there are significant improvements in runoff.

  12. Middle-Upper Permian carbon isotope stratigraphy at Chaotian, South China: Pre-extinction multiple upwelling of oxygen-depleted water onto continental shelf

    NASA Astrophysics Data System (ADS)

    Saitoh, Masafumi; Isozaki, Yukio; Ueno, Yuichiro; Yoshida, Naohiro; Yao, Jianxin; Ji, Zhansheng

    2013-05-01

    In order to examine the causal relationships between the carbon cycle in a shallow euphotic zone and the environmental changes in a relatively deep disphotic zone at the end-Guadalupian (Middle Permian), isotopic compositions of carbonate carbon (δ13Ccarb) of the Guadalupian-Lopingian (Upper Permian) rocks were analyzed in the Chaotian section in northern Sichuan, South China. By analyzing exceptionally fresh drill core samples, a continuous chemostratigraphic record was newly obtained. The ca. 65 m-thick analyzed carbonate rocks at Chaotian comprise three stratigraphic units, i.e., the Limestone Unit of the Guadalupian Maokou Formation, the Mudstone Unit of the Maokou Formation, and the lower part of the Wuchiapingian (Lower Lopingian) Wujiaping Formation, in ascending order. The Limestone Unit of the Maokou Formation is characterized by almost constant δ13Ccarb values of ca. +4‰ followed by an abrupt drop for 7‰ to -3‰ in the topmost part of the unit. In the Mudstone Unit of the Maokou Formation, the δ13Ccarb values are rather constant around +2‰, although distinct three isotopic negative excursions for 3‰ from ca. +2 to -1‰ occurred in the upper part of the unit. In the lower part of the Wujiaping Formation, the δ13Ccarb values monotonously increase for 5‰ from ca. 0 to +5‰. The present data newly demonstrated four isotopic negative excursions in the topmost part of the Maokou Formation in the Capitanian (Late Guadalupian) at Chaotian. It is noteworthy that these negative excursions are in accordance with the emergence of an oxygen-depleted condition on the relatively deep disphotic slope/basin on the basis of litho- and bio-facies characteristics. They suggest multiple upwelling of oxygen-depleted waters with dissolved inorganic carbon of relatively low carbon isotope values along the continental margin, from the deeper disphotic slope/basin to the shallower euphotic shelf, slightly before the end-Guadalupian extinction. Although the

  13. Production of heavy water

    DOEpatents

    Spencer, Larry S.; Brown, Sam W.; Phillips, Michael R.

    2017-06-06

    Disclosed are methods and apparatuses for producing heavy water. In one embodiment, a catalyst is treated with high purity air or a mixture of gaseous nitrogen and oxygen with gaseous deuterium all together flowing over the catalyst to produce the heavy water. In an alternate embodiment, the deuterium is combusted to form the heavy water. In an alternate embodiment, gaseous deuterium and gaseous oxygen is flowed into a fuel cell to produce the heavy water. In various embodiments, the deuterium may be produced by a thermal decomposition and distillation process that involves heating solid lithium deuteride to form liquid lithium deuteride and then extracting the gaseous deuterium from the liquid lithium deuteride.

  14. Polarized hydrogen/deuterium molecules

    NASA Astrophysics Data System (ADS)

    Shestakov, Yu V.; Nikolenko, D. M.; Rachek, I. A.; Sadykov, R. Sh; Toporkov, D. K.; Yurchenko, A. V.; Zevakov, S. A.

    2017-12-01

    The prototype of a polarized molecular hydrogen/deuterium source which is based on the classical Stern-Gerlach separation scheme has been tested at the Budker Institute of Nuclear Physics (BINP), Novosibirsk. It consists of the circular slit nozzle cooled down to 6.5 K and the two superconducting sextupole magnets. The flux of polarized hydrogen molecules of 3·1012 mol/s was measured for a total gas flow through the nozzle of 5·10-2 Torr·l/s. The obtained results will be used to develop a much more intense source of polarized molecules.

  15. More than just one Methane Paradox? - Methane Production in Oxic Waters and Aerobic Methane Oxidation under Oxygen-Depleted Conditions

    NASA Astrophysics Data System (ADS)

    Lehmann, M. F.; Niemann, H.; Bartosiewicz, M.; Blees, J.; Steinle, L.; Su, G.; Zopfi, J.

    2016-12-01

    The standing paradigm is that methane (CH4) production through methanogenesis occurs exclusively under anoxic conditions and that at least in freshwater environments most of the biogenic CH4 is oxidized by aerobic methanotrophic bacteria (MOB) under oxic conditions. However, subsurface CH4 accumulation in oxic waters, a phenomenon referred to as the "CH4 paradox", has been observed both in the ocean and in lakes, and suggests in-situ CH4 production or a remarkable tolerance of at least some methanogens to O2. Analogously, MOB seem to thrive also under micro-oxic conditions, i.e., they may be responsible for significant CH4 turnover at extremely low O2 concentrations. O2 availability particularly within the sub-micromolar range is likely one of the key factors controlling the balance between CH4 production and consumption in redox-transition zones of aquatic environments, yet threshold O2 concentrations are poorly constrained. Here we provide multiple lines of evidence for apparent "methanogenesis" in well-oxygenated waters and discuss the potential mechanisms that lead to CH4 accumulation in the oxic epilimnia of two south-alpine lakes. On the other end, we present data from a deep meromictic lake, which indicate aerobic CH4 oxidation (MOx) at O2 concentrations below the detection limit of common O2 sensors. A strong MOx potential throughout the anoxic hyplimnion of the studied lake implies that the MOB community is able to survive prolonged periods of O2 starvation and is capable to rapidly resume microaerobic MOx upon introduction of low levels of O2. This conclusion is qualitatively consistent with field data from a coastal shelf environment in the Baltic Sea, where we observed maximum MOx rates during the summer stratification period when O2 concentrations were lowest, implying that in both environments MOx bacteria are adapted to trace levels of O2. Indeed, laboratory experiments at different manipulated O2 concentration levels suggest a nanomolar O2 optimum

  16. 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 andmore » 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.« less

  17. The Impact of Nonequilibrium and Equilibrium Fractionation on Two Different Deuterium Excess Definitions

    NASA Astrophysics Data System (ADS)

    Dütsch, Marina; Pfahl, Stephan; Sodemann, Harald

    2017-12-01

    The deuterium excess (d) is a useful measure for nonequilibrium effects of isotopic fractionation and can therefore provide information about the meteorological conditions in evaporation regions or during ice cloud formation. In addition to nonequilibrium fractionation, two other effects can change d during phase transitions. The first is the dependence of the equilibrium fractionation factors on temperature, and the second is the nonlinearity of the δ scale on which d is defined. The second effect can be avoided by using an alternative definition that is based on the logarithmic scale. However, in this case d is not conserved when air parcels mix, which can lead to changes without phase transitions. Here we provide a systematic analysis of the benefits and limitations of both deuterium excess definitions by separately quantifying the impact of the nonequilibrium effect, the temperature effect, the δ-scale effect, and the mixing effect in a simple Rayleigh model simulating the isotopic composition of air parcels during moist adiabatic ascent. The δ-scale effect is important in depleted air parcels, for which it can change the sign of the traditional deuterium excess in the remaining vapor from negative to positive. The alternative definition mainly reflects the nonequilibrium and temperature effect, while the mixing effect is about 2 orders of magnitude smaller. Thus, the alternative deuterium excess definition appears to be a more accurate measure for nonequilibrium effects in situations where moisture is depleted and the δ-scale effect is large, for instance, at high latitudes or altitudes.

  18. On-farm irrigation reservoirs for surface water storage in eastern Arkansas: Trends in construction in response to aquifer depletion

    NASA Astrophysics Data System (ADS)

    Yaeger, M. A.; Reba, M. L.; Massey, J. H.; Adviento-Borbe, A.

    2017-12-01

    On-farm surface water storage reservoirs have been constructed to address declines in the Mississippi River Valley Alluvial aquifer, the primary source of irrigation for most of the row crops grown in eastern Arkansas. These reservoirs and their associated infrastructure represent significant investments in financial and natural resources, and may cause producers to incur costs associated with foregone crop production and long-term maintenance. Thus, an analysis of reservoir construction trends in the Grand Prairie Critical Groundwater Area (GPCGA) and Cache River Critical Groundwater Area (CRCGA) was conducted to assist future water management decisions. Between 1996 and 2015, on average, 16 and 4 reservoirs were constructed per year, corresponding to cumulative new reservoir surface areas of 161 and 60 ha yr-1, for the GPCGA and the CRCGA, respectively. In terms of reservoir locations relative to aquifer status, after 1996, 84.5% of 309 total reservoirs constructed in the GPCGA and 91.0% of 78 in the CRCGA were located in areas with remaining saturated aquifer thicknesses of 50% or less. The majority of new reservoirs (74% in the GPCGA and 63% in the CRCGA) were constructed on previously productive cropland. The next most common land use, representing 11% and 15% of new reservoirs constructed in the GPCGA and CRCGA, respectively, was the combination of a field edge and a ditch, stream, or other low-lying area. Less than 10% of post-1996 reservoirs were constructed on predominately low-lying land, and the use of such lands decreased in both critical groundwater areas during the past 20 years. These disparities in reservoir construction rates, locations, and prior land uses is likely due to groundwater declines being first observed in the GPCGA as well as the existence of two large-scale river diversion projects under construction in the GPCGA that feature on-farm storage as a means to offset groundwater use.

  19. 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.

  20. EFFECT OF DEUTERIUM OXIDE ON THE REPRODUCTIVE POTENTIAL OF MICE

    SciTech Connect

    Czajka, D.M.; Finkel, A.J.

    1960-11-25

    Replacement of hydrogen with deuterium by the administration of 25% D/ sub 2/O in the drinkng water resulted in certain alterations in the reproductive potential of female mice, These changes included an apparent decrease in the number of pregnancies carried close to term, an increase in the incidence of wholly nonviable litters, and a decrease in the survival of newborn mice. Examination of uterine contents late in pregnancy, however, revealed that neither the incidence of pregnancy nor the mean number of implanted embryos per pregnant female was correlated with the duration of deuteration. Reduction of the incidence of viable newbornmore » mice in part reflected the increase in nonviability of fetuses examined in utero late in gestation and in part may have been the result of maternal cannibalism. Reduction of fetal viability was greatest when the dams had been substantially deuterated at the time of implantation of the fetus, which occurred at about the fifth day after mating. When the administration of deuterium to female mice preceded mating by 1 week, the higher the level of deuteration, the lower was the total fetal viability. A critical level appeared to exist here between 25 and 30 at.% deuterium in the drinking water, above which fetal viability ceased. The reduction of mean litter size and of viability of the newbern was at least partly reversible by restoring the dams to ordinary drinking water. (auth)« less

  1. Carbon isotope fractionation during diamond growth in depleted peridotite: Counterintuitive insights from modelling water-maximum CHO fluids as multi-component systems

    NASA Astrophysics Data System (ADS)

    Stachel, T.; Chacko, T.; Luth, R. W.

    2017-09-01

    Because of the inability of depleted cratonic peridotites to effectively buffer oxygen fugacities when infiltrated by CHO or carbonatitic fluids, it has been proposed recently (Luth and Stachel, 2014) that diamond formation in peridotites typically does not occur by rock-buffered redox reactions as previously thought but by an oxygen-conserving reaction in which minor coexisting CH4 and CO2 components in a water-rich fluid react to form diamond (CO2 + CH4 = 2C + 2H2O). In such fluid-buffered systems, carbon isotope fractionation during diamond precipitation occurs in the presence of two dominant fluid carbon species. Carbon isotope modelling of diamond precipitation from mixed CH4- and CO2-bearing fluids reveals unexpected fundamental differences relative to diamond crystallization from a single carbon fluid species: (1) irrespective of which carbon fluid species (CH4 or CO2) is dominant in the initial fluid, diamond formation is invariably associated with progressive minor (<1‰) enrichment of diamond in 13C as crystallization proceeds. This is in contrast to diamond precipitation by rock-buffered redox processes from a fluid containing only a single carbon species, which can result in either progressive 13C enrichment (CO2 or carbonate fluids) or 13C depletion (CH4 fluids) in the diamond. (2) Fluid speciation is the key factor controlling diamond δ13 C values; as XCO2 (XCO2 = CO2/[CO2 + CH4]) in the initial fluid increases from 0.1 to 0.9 (corresponding to an increase in fO2 of 0.8 log units), the carbon isotope composition of the first-precipitated diamond decreases by 3.7‰. The tight mode in δ13C of - 5 ± 1 ‰ for diamonds worldwide places strict constraints on the dominant range of XCO2 in water-rich fluids responsible for diamond formation. Specifically, precipitation of diamonds with δ13C values in the range -4 to -6‰ from mantle-derived fluids with an average δ13C value of -5‰ (derived from evidence not related to diamonds) requires that

  2. Water, High-altitude Condensates, and Possible Methane Depletion in the Atmosphere of the Warm Super-Neptune WASP-107b

    NASA Astrophysics Data System (ADS)

    Kreidberg, Laura; Line, Michael R.; Thorngren, Daniel; Morley, Caroline V.; Stevenson, Kevin B.

    2018-05-01

    The super-Neptune exoplanet WASP-107b is an exciting target for atmosphere characterization. It has an unusually large atmospheric scale height and a small, bright host star, raising the possibility of precise constraints on its current nature and formation history. We report the first atmospheric study of WASP-107b, a Hubble Space Telescope (HST) measurement of its near-infrared transmission spectrum. We determined the planet’s composition with two techniques: atmospheric retrieval based on the transmission spectrum and interior structure modeling based on the observed mass and radius. The interior structure models set a 3σ upper limit on the atmospheric metallicity of 30× solar. The transmission spectrum shows strong evidence for water absorption (6.5σ confidence), and the retrieved water abundance is consistent with expectations for a solar abundance pattern. The inferred carbon-to-oxygen ratio is subsolar at 2.7σ confidence, which we attribute to possible methane depletion in the atmosphere. The spectral features are smaller than predicted for a cloud-free composition, crossing less than one scale height. A thick condensate layer at high altitudes (0.1–3 mbar) is needed to match the observations. We find that physically motivated cloud models with moderate sedimentation efficiency (f sed = 0.3) or hazes with a particle size of 0.3 μm reproduce the observed spectral feature amplitude. Taken together, these findings serve as an illustration of the diversity and complexity of exoplanet atmospheres. The community can look forward to more such results with the high precision and wide spectral coverage afforded by future observing facilities.

  3. The translational, rotational, and vibrational energy effects on the chemical reactivity of water cation H2O+(X 2B1) in the collision with deuterium molecule D2

    NASA Astrophysics Data System (ADS)

    Xu, Yuntao; Xiong, Bo; Chang, Yih Chung; Ng, C. Y.

    2013-07-01

    By employing the newly established vacuum ultraviolet (VUV) laser pulsed field ionization-photoion (PFI-PI) double quadrupole-double octopole ion guide apparatus, we have examined the translational, rotational, and vibrational energy effects on the chemical reactivity of water cation H2O+(X2B1) in the collision with deuterium molecule D2. The application of a novel electric-field pulsing scheme to the VUV laser PFI-PI ion source has enabled the preparation of a rovibrationally selected H2O+(X2B1; v_1^ + v_2^ + v_3^ +; N+Ka+Kc+) ion beam with not only high internal-state selectivity and high intensity but also high translational energy resolution. Despite the unfavorable Franck-Condon factors, we are able to prepare the excited vibrational states (v_1^ + v_2^ + v_3^ +) = (100) and (020) along with the (000) ground vibrational state, for collisional studies, where v_1^ +, v_2^ +, and v_3^ + represent the symmetric stretching, bending, and asymmetric stretching modes of H2O+(X2B1). We show that a range of rotational levels from N+Ka+Kc+ = 000 to 322, covering a rotational energy range of 0-200 cm-1 of these vibrational states, can also be generated for absolute integral cross section (σ) measurements at center-of-mass collision energies (Ecms) from thermal energies to 10.00 eV. The Ecm dependences of the σ values are consistent with the prediction of the orbiting model, indicating that translational energy significantly hinders the chemical reactivity of H2O+(X2B1). Rotational enhancements are observed at Ecm < 0.30 eV for all the three vibrational states, (000), (100), and (020). While the σ values for (100) are found to be only slightly below those for (000), the σ values for (020) are lower than those for (000) and (100) by up to 20% at Ecm ≤ 0.20 eV, indicative of vibrational inhibition at low Ecm by excitation of the (020) mode. Rationalizations are proposed for the observed rotational enhancements and the bending vibrational inhibition. Rigorous

  4. Distribution of inorganic and organic nutrients in the South Pacific Ocean - evidence for long-term accumulation of organic matter in nitrogen-depleted waters

    NASA Astrophysics Data System (ADS)

    Raimbault, P.; Garcia, N.; Cerutti, F.

    2007-08-01

    . Extensive comparison has shown that glass fiber GF/F filters efficiency collected particulate chlorophyll, while a significant fraction of POM (up to 50%) passed trough this filter and was retained by 0.2 μm Teflon membrane. The most striking feature was the large accumulation of dissolved organic matter (DOM) in the SPG relative to surrounding waters, especially dissolved organic carbon (DOC) where concentrations were at levels rarely measured in oceanic waters (>100 μmoles l-1). Due to this large pool of DOM over the whole photic layer of the SPG, integrated values followed an opposite geographical pattern than this of inorganic nutrients with a large accumulation within the centre of the SPG. While suspended particulate matter in the mixed layer had C/N ratio largely conform to Redfield stoichiometry (C/N≍6.6), marked deviations were observed in this excess DOM (C/N≍16 to 23). The existence of C-rich dissolved organic matter is recognized as a feature typical of oligotrophic waters, requiring the over consumption of carbon. Thus, in spite of strong nitrate-depletion leading to low chlorophyll biomass, the closed ecosystem of the SPG can produce a large amount of carbon. The implications of this finding are discussed, the conclusion being that, due to the lack of seasonal vertical mixing and weak lateral advection, the dissolved organic carbon biologically produced can be accumulated and stored in the photic layer for a very long period.

  5. Deuterium retention and release behaviours of tungsten and deuterium co-deposited layers

    NASA Astrophysics Data System (ADS)

    Qiao, L.; Zhang, H. W.; Xu, J.; Chai, L. Q.; Hu, M.; Wang, P.

    2018-04-01

    Tungsten (W) layer deposited in argon and deuterium atmosphere by magnetron sputtering was used as a model system to study the deuterium (D) retention and release behavior in co-deposited W layer. After deposition several selected samples were exposed in deuterium plasma at 370 K with a flux of 4.0 × 1021 D/(m2 s) up to a fluence of 1.1 × 1025 D/m2. Structures of co-deposited W layers are investigated by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD), and the corresponding D retention and release behaviors are studied as functions of deposition and exposure parameters using thermal desorption spectroscopy (TDS). Two main D release peaks were detected from TDS spectra located near 600 and 800 K in these W and D co-deposited layers, and total deuterium retention increased linearly as a function of W layer's thickness. After deuterium plasma exposure, the total D retention amount in W layer increases significantly and D release peak shifts to lower temperature. Clearly, despite the high density of defects expected in co-deposited W layers, the initial deuterium retention before exposure to the deuterium plasma is low even for the samples with a W&D layer. But due to the high densities of defects, during the deuterium plasma exposure the deuterium retention increases faster for co-deposited layer than for the bulk W sample.

  6. EFFECTS OF DEUTERIUM OXIDE UPON POLIOVIRUS MULTIPLICATION

    SciTech Connect

    Carp, R.I.; Kritchevsky, D.; Koprowski, H.

    1960-09-01

    The effects of deuterium oxide on the multiplication of CHAT, an attenuated type of poliomyeliths virus, was studied in cells of HeLa and of monkey kidney cells in primary cultures. Yields of virus obtained from deuterated cells were consistently higher than those obtained from controls. The incorporation of deuterium oxide in the growth media resulted in an increase in the average plague size of polio virus. (C.H.)

  7. 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.

  8. Energy Levels of Hydrogen and Deuterium

    National Institute of Standards and Technology Data Gateway

    SRD 142 NIST 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.

  9. Infrared absorption of methanol-water clusters (CH3OH)n(H2O), n = 1-4, recorded with the VUV-ionization/IR-depletion technique

    NASA Astrophysics Data System (ADS)

    Lee, Yu-Fang; Kelterer, Anne-Marie; Matisz, Gergely; Kunsági-Máté, Sándor; Chung, Chao-Yu; Lee, Yuan-Pern

    2017-04-01

    We recorded infrared (IR) spectra in the CH- and OH-stretching regions of size-selected clusters of methanol (M) with one water molecule (W), represented as MnW, n = 1-4, in a pulsed supersonic jet using the photoionization/IR-depletion technique. Vacuum ultraviolet emission at 118 nm served as the source of ionization in a time-of-flight mass spectrometer to detect clusters MnW as protonated forms Mn-1WH+. The variations in intensities of Mn-1WH+ were monitored as the wavelength of the IR laser light was tuned across the range 2700-3800 cm-1. IR spectra of size-selected clusters were obtained on processing of the observed action spectra of the related cluster-ions according to a mechanism that takes into account the production and loss of each cluster due to IR photodissociation. Spectra of methanol-water clusters in the OH region show significant variations as the number of methanol molecules increases, whereas those in the CH region are similar for all clusters. Scaled harmonic vibrational wavenumbers and relative IR intensities predicted with the M06-2X/aug-cc-pVTZ method for the methanol-water clusters are consistent with our experimental results. For dimers, absorption bands of a structure WM with H2O as a hydrogen-bond donor were observed at 3570, 3682, and 3722 cm-1, whereas weak bands of MW with methanol as a hydrogen-bond donor were observed at 3611 and 3753 cm-1. For M2W, the free OH band of H2O was observed at 3721 cm-1, whereas a broad feature was deconvoluted to three bands near 3425, 3472, and 3536 cm-1, corresponding to the three hydrogen-bonded OH-stretching modes in a cyclic structure. For M3W, the free OH shifted to 3715 cm-1, and the hydrogen-bonded OH-stretching bands became much broader, with a weak feature near 3179 cm-1 corresponding to the symmetric OH-stretching mode of a cyclic structure. For M4W, the observed spectrum agrees unsatisfactorily with predictions for the most stable cyclic structure, indicating significant contributions from

  10. Infrared absorption of methanol-water clusters (CH3OH)n(H2O), n = 1-4, recorded with the VUV-ionization/IR-depletion technique.

    PubMed

    Lee, Yu-Fang; Kelterer, Anne-Marie; Matisz, Gergely; Kunsági-Máté, Sándor; Chung, Chao-Yu; Lee, Yuan-Pern

    2017-04-14

    We recorded infrared (IR) spectra in the CH- and OH-stretching regions of size-selected clusters of methanol (M) with one water molecule (W), represented as M n W, n = 1-4, in a pulsed supersonic jet using the photoionization/IR-depletion technique. Vacuum ultraviolet emission at 118 nm served as the source of ionization in a time-of-flight mass spectrometer to detect clusters M n W as protonated forms M n-1 WH + . The variations in intensities of M n-1 WH + were monitored as the wavelength of the IR laser light was tuned across the range 2700-3800 cm -1 . IR spectra of size-selected clusters were obtained on processing of the observed action spectra of the related cluster-ions according to a mechanism that takes into account the production and loss of each cluster due to IR photodissociation. Spectra of methanol-water clusters in the OH region show significant variations as the number of methanol molecules increases, whereas those in the CH region are similar for all clusters. Scaled harmonic vibrational wavenumbers and relative IR intensities predicted with the M06-2X/aug-cc-pVTZ method for the methanol-water clusters are consistent with our experimental results. For dimers, absorption bands of a structure WM with H 2 O as a hydrogen-bond donor were observed at 3570, 3682, and 3722 cm -1 , whereas weak bands of MW with methanol as a hydrogen-bond donor were observed at 3611 and 3753 cm -1 . For M 2 W, the free OH band of H 2 O was observed at 3721 cm -1 , whereas a broad feature was deconvoluted to three bands near 3425, 3472, and 3536 cm -1 , corresponding to the three hydrogen-bonded OH-stretching modes in a cyclic structure. For M 3 W, the free OH shifted to 3715 cm -1 , and the hydrogen-bonded OH-stretching bands became much broader, with a weak feature near 3179 cm -1 corresponding to the symmetric OH-stretching mode of a cyclic structure. For M 4 W, the observed spectrum agrees unsatisfactorily with predictions for the most stable cyclic structure

  11. 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.

  12. Deuterium Tetrabenazine for Tardive Dyskinesia.

    PubMed

    Cummings, Michael A; Proctor, George J; Stahl, Stephen M

    2018-01-01

    Tardive dyskinesia remains a significant, potentially stigmatizing or crippling adverse effect for any patient treated with an antipsychotic medication. While second- and third-generation antipsychotics have exhibited lower annual incidence rates for tardive dyskinesia than classic or first-generation agents, 3.9% versus 5.5%, the estimated incidence rate is only modestly lower. When coupled with the fact that second- and third-generation antipsychotic medications have come to be employed in treating a wider range of disorders (e.g., autism spectrum disorders, mood disorders, personality disorders, etc.), it is clear that the population of patients exposed to the risk of tardive dyskinesia has expanded. On April 3, 2017, the U.S. Food and Drug Administration (FDA) approved a deuterated version of tetrabenazine (Xenozine®) for the treatment of the involuntary choreic movements associated with Huntington's disease. More recent data, however, have indicated that deuterium tetrabenazine or deutetrabenazine (Austedo®) is effective in treating tardive dyskinesia. Moreover, like the other derivative of tetrabenazine, valbenazine (Ingrezza®), deutetrabenazine offers less frequent dosing and a better short-term adverse effect profile than that of tetrabenazine. Longer use in a broader range of patients, however, will be required to identify risks and benefits not found in short-term trials, as well as optimal use parameters for treatment of tardive dyskinesia.

  13. Enhancement of photoassembly of the functionally active water-oxidizing complex in Mn-depleted photosystem II membranes upon transition to anaerobic conditions.

    PubMed

    Khorobrykh, A A; Yanykin, D V; Klimov, V V

    2016-10-01

    It has been shown earlier (Khorobrykh and Klimov, 2015) that molecular oxygen is directly involved in the general mechanism of the donor side photoinhibition of photosystem II (PSII) membranes. In the present work the effect of oxygen on photoassembly ("photoactivation") of the functionally active inorganic core of the water-oxidizing complex (WOC) in Mn-depleted PSII preparations (apo-WOC-PSII) in the presence of exogenous Mn(2+), Ca(2+) as well as ferricyanide was investigated. It was revealed that the efficiency of the photoassembly of the WOC was considerably increased upon removal of oxygen from the medium during photoactivation procedure using the enzymatic oxygen trap or argon flow. The lowering of O2 concentration from 250μM to 75μM, 10μM and near 0μM results in 29%, 71% and 92%, respectively, stimulation of the rate of O2 evolution measured after the photoactivation. The increase in the intensity of light used during the photoactivation was accompanied by a decrease of both the efficiency of photoassembly of the WOC and the stimulation effect of removal of O2 (that may be due to the enhancement of the processes leading to the photodamage to PSII). It is concluded that the enhancement in photoactivation of oxygen-evolving activity of apo-WOC-PSII induced by oxygen removal from the medium is due to the suppression of the donor side photoinhibition of PSII in which molecular oxygen can be involved. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. The Variability of Atmospheric Deuterium Brightness at Mars: Evidence for Seasonal Dependence

    NASA Astrophysics Data System (ADS)

    Mayyasi, Majd; Clarke, John; Bhattacharyya, Dolon; Deighan, Justin; Jain, Sonal; Chaffin, Michael; Thiemann, Edward; Schneider, Nick; Jakosky, Bruce

    2017-10-01

    The enhanced ratio of deuterium to hydrogen on Mars has been widely interpreted as indicating the loss of a large column of water into space, and the hydrogen content of the upper atmosphere is now known to be highly variable. The variation in the properties of both deuterium and hydrogen in the upper atmosphere of Mars is indicative of the dynamical processes that produce these species and propagate them to altitudes where they can escape the planet. Understanding the seasonal variability of D is key to understanding the variability of the escape rate of water from Mars. Data from a 15 month observing campaign, made by the Mars Atmosphere and Volatile Evolution Imaging Ultraviolet Spectrograph high-resolution echelle channel, are used to determine the brightness of deuterium as observed at the limb of Mars. The D emission is highly variable, with a peak in brightness just after southern summer solstice. The trends of D brightness are examined against extrinsic as well as intrinsic sources. It is found that the fluctuations in deuterium brightness in the upper atmosphere of Mars (up to 400 km), corrected for periodic solar variations, vary on timescales that are similar to those of water vapor fluctuations lower in the atmosphere (20-80 km). The observed variability in deuterium may be attributed to seasonal factors such as regional dust storm activity and subsequent circulation lower in the atmosphere.

  15. A GREAT search for Deuterium in Comets

    NASA Astrophysics Data System (ADS)

    Mumma, Michael

    2012-10-01

    Comets are understood to be the most pristine bodies in the Solar System. Their compositions reflect the chemical state of materials at the very earliest evolutionary stages of the protosolar nebula and, as such, they provide detailed insight into the physical and chemical processes operating in planet-forming disks. Isotopic fractionation ratios of the molecular ices in the nucleus are regarded as signatures of formation processes. These ratios provide unique information on the natal heritage of those ices, and can also test the proposal that Earth's water and other volatiles were delivered by cometary bombardment. Measurement of deuterium fractionation ratios is thus a major goal in contemporary cometary science and the D/H ratio of water - the dominant volatile in comets - holds great promise for testing the formation history of cometary matter. The D/H ratio in cometary water has been measured in only seven comets. Six were from the Oort Cloud reservoir and the D/H ratio was about twice that of the Earth's oceans. However, the recent Herschel measurement of HDO/H2O in 103P/Hartley-2 (the first from the Kuiper Belt) was consistent with exogenous delivery of Earth's water by comets. Outstanding questions remain: are cometary HDO/H2O ratios consistent with current theories of nebular chemical evolution or with an interstellar origin? Does the HDO/H2O ratio vary substantially among comet populations? Hartley-2 is the only Kuiper Belt comet with measured HDO/H2O, are there comets with similar ratios in the Oort cloud? These questions can only be addressed by measuring HDO/H2O ratios in many more suitable bright comets. We therefore propose to measure the D/H ratio in water in a suitable target-of-opportunity comet by performing observations of HDO and OH with the GREAT spectrometer on SOFIA. A multi-wavelength, ground-based observing campaign will also be conducted in support of the airborne observations.

  16. A GREAT search for Deuterium in Comets

    NASA Astrophysics Data System (ADS)

    Mumma, Michael

    2013-10-01

    Comets are understood to be the most pristine bodies in the Solar System. Their compositions reflect the chemical state of materials at the very earliest evolutionary stages of the protosolar nebula and, as such, they provide detailed insight into the physical and chemical processes operating in planet-forming disks. Isotopic fractionation ratios of the molecular ices in the nucleus are regarded as signatures of formation processes. These ratios provide unique information on the natal heritage of those ices, and can also test the proposal that Earth's water and other volatiles were delivered by cometary bombardment. Measurement of deuterium fractionation ratios is thus a major goal in contemporary cometary science and the D/H ratio of water - the dominant volatile in comets - holds great promise for testing the formation history of cometary matter. The D/H ratio in cometary water has been measured in only eight comets. Seven were from the Oort Cloud reservoir and the D/H ratio was about twice that of the Earth's oceans. However, the recent Herschel measurement of HDO/H2O in 103P/Hartley-2 (the first from the Kuiper Belt) was consistent with exogenous delivery of Earth's water by comets. Outstanding questions remain: are cometary HDO/H2O ratios consistent with current theories of nebular chemical evolution or with an interstellar origin? Does the HDO/H2O ratio vary substantially among comet populations? Hartley-2 is the only Kuiper Belt comet with measured HDO/H2O, are there comets with similar ratios in the Oort cloud? These questions can only be addressed by measuring HDO/H2O ratios in many more suitable bright comets. We therefore propose to measure the D/H ratio in water in a suitable target-of-opportunity comet by performing observations of HDO and OH with the GREAT spectrometer on SOFIA. A multi-wavelength, ground-based observing campaign will also be conducted in support of the airborne observations.

  17. Polar stratospheric clouds and ozone depletion

    NASA Technical Reports Server (NTRS)

    Toon, Owen B.; Turco, Richard P.

    1991-01-01

    A review is presented of investigations into the correlation between the depletion of ozone and the formation of polar stratospheric clouds (PSCs). Satellite measurements from Nimbus 7 showed that over the years the depletion from austral spring to austral spring has generally worsened. Approximately 70 percent of the ozone above Antarctica, which equals about 3 percent of the earth's ozone, is lost during September and October. Various hypotheses for ozone depletion are discussed including the theory suggesting that chlorine compounds might be responsible for the ozone hole, whereby chlorine enters the atmosphere as a component of chlorofluorocarbons produced by humans. The three types of PSCs, nitric acid trihydrate, slowly cooling water-ice, and rapidly cooling water-ice clouds act as important components of the Antarctic ozone depletion. It is indicated that destruction of the ozone will be more severe each year for the next few decades, leading to a doubling in area of the Antarctic ozone hole.

  18. Depleted Uranium: Technical Brief

    EPA Pesticide Factsheets

    This technical brief provides accepted data and references to additional sources for radiological and chemical characteristics, health risks and references for both the monitoring and measurement, and applicable treatment techniques for depleted uranium.

  19. Addressing Ozone Layer Depletion

    EPA Pesticide Factsheets

    Access information on EPA's efforts to address ozone layer depletion through regulations, collaborations with stakeholders, international treaties, partnerships with the private sector, and enforcement actions under Title VI of the Clean Air Act.

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

    PubMed

    Chacko, Shaji K; Sunehag, Agneta L; Sharma, Susan; Sauer, Pieter J J; Haymond, Morey W

    2008-04-01

    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 gluconeogenesis are based on measurements of the average enrichment of deuterium on carbon 1, 3, 4, 5, and 6 of glucose and the deuterium enrichment in body water. In a sample from an adult volunteer after ingestion of deuterium oxide, fractional gluconeogenesis using the "average deuterium enrichment method" was 48.3 +/- 0.5% (mean +/- SD) and that with the C-5 hexamethylenetetramine (HMT) method by Landau et al. (Landau BR, Wahren J, Chandramouli V, Schumann WC, Ekberg K, Kalhan SC; J Clin Invest 98: 378-385, 1996) was 46.9 +/- 5.4%. The coefficient of variation of 10 replicate analyses using the new method was 1.0% compared with 11.5% for the C-5 HMT method. In samples derived from an infant receiving total parenteral nutrition, fractional gluconeogenesis was 13.3 +/- 0.3% using the new method and 13.7 +/- 0.8% using the C-5 HMT method. Fractional gluconeogenesis measured in six adult volunteers after 66 h of continuous fasting was 83.7 +/- 2.3% using the new method and 84.2 +/- 5.0% using the C-5 HMT method. In conclusion, the average deuterium enrichment method is simple, highly reproducible, and cost effective. Furthermore, it requires only small blood sample volumes. With the use of an additional tracer, glucose rate of appearance can also be measured during the same analysis. Thus the new method makes measurements of gluconeogenesis available and affordable to large numbers of investigators under conditions of low and high fractional gluconeogenesis ( approximately 10 to approximately 90) in all subject populations.

  1. Buscopan labeled with carbon-14 and deuterium.

    PubMed

    Latli, Bachir; Stiasni, Michael; Hrapchak, Matt; Li, Zhibin; Grinberg, Nelu; Lee, Heewon; Busacca, Carl A; Senanayake, Chris H

    2016-11-01

    Hyosine butyl bromide, the active ingredient in Buscopan, is an anticholinergic and antimuscarinic drug used to treat pain and discomfort caused by abdominal cramps. A straightforward synthesis of carbon-14- and deuterium-labeled Buscopan was developed using scopolamine, n-butyl-1- 14 C bromide, and n-butyl- 2 H 9 bromide, respectively. In a second carbon-14 synthesis, the radioactive carbon was incorporated in the tropic acid moiety to follow its metabolism. Herein, we describe the detailed preparations of carbon-14- and deuterium-labeled Buscopan. Copyright © 2016 John Wiley & Sons, Ltd.

  2. DEHYDRATION OF DEUTERIUM OXIDE SLURRIES

    DOEpatents

    Hiskey, C.F.

    1959-03-10

    A method is presented for recovering heavy water from uranium oxide-- heavy water slurries. The method consists in saturating such slurries with a potassium nitrate-sodium nitrate salt mixture and then allowing the self-heat of the slurry to raise its temperature to a point slightly in excess of 100 deg C, thus effecting complete evaporation of the free heavy water from the slurry. The temperature of the slurry is then allowed to reach 300 to 900 deg C causing fusion of the salt mixture and expulsion of the water of hydration. The uranium may be recovered from the fused salt mixture by treatment with water to leach the soluble salts away from the uranium-containing residue.

  3. 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.

  4. Kinetic deuterium isotope effects in glucocorticoid receptor activation

    SciTech Connect

    Aranyi, P.

    1984-01-01

    Activation and deactivation of the chick thymus glucocorticoid receptor protein was studied in ordinary and heavy water by DNA-cellulose binding of the tritiated triamcinolone acetonide-receptor complex. Activation was significantly slower in heavy water if it was promoted by incubation at elevated temperature in buffers of low ionic strength. In the presence of 300 mM KC1 or after separation from the low molecular weight cytosol constituents, the complex was activated at the same rate in both solvents. Deactivation (time dependent loss of DNA-binding capacity) was much faster in ordinary than in heavy water regardless of gel filtration or the presence ofmore » KC1. A model of receptor activation-deactivation was constructed on the basis of these data that accounts for the observed kinetic deuterium isotope effects and reveals some submolecular details of the process.« less

  5. 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.

  6. New Approach For Prediction Groundwater Depletion

    NASA Astrophysics Data System (ADS)

    Moustafa, Mahmoud

    2017-01-01

    Current approaches to quantify groundwater depletion involve water balance and satellite gravity. However, the water balance technique includes uncertain estimation of parameters such as evapotranspiration and runoff. The satellite method consumes time and effort. The work reported in this paper proposes using failure theory in a novel way to predict groundwater saturated thickness depletion. An important issue in the failure theory proposed is to determine the failure point (depletion case). The proposed technique uses depth of water as the net result of recharge/discharge processes in the aquifer to calculate remaining saturated thickness resulting from the applied pumping rates in an area to evaluate the groundwater depletion. Two parameters, the Weibull function and Bayes analysis were used to model and analyze collected data from 1962 to 2009. The proposed methodology was tested in a nonrenewable aquifer, with no recharge. Consequently, the continuous decline in water depth has been the main criterion used to estimate the depletion. The value of the proposed approach is to predict the probable effect of the current applied pumping rates on the saturated thickness based on the remaining saturated thickness data. The limitation of the suggested approach is that it assumes the applied management practices are constant during the prediction period. The study predicted that after 300 years there would be an 80% probability of the saturated aquifer which would be expected to be depleted. Lifetime or failure theory can give a simple alternative way to predict the remaining saturated thickness depletion with no time-consuming processes such as the sophisticated software required.

  7. 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

  8. Revisiting Antarctic Ozone Depletion

    NASA Astrophysics Data System (ADS)

    Grooß, Jens-Uwe; Tritscher, Ines; Müller, Rolf

    2015-04-01

    Antarctic ozone depletion is known for almost three decades and it has been well settled that it is caused by chlorine catalysed ozone depletion inside the polar vortex. However, there are still some details, which need to be clarified. In particular, there is a current debate on the relative importance of liquid aerosol and crystalline NAT and ice particles for chlorine activation. Particles have a threefold impact on polar chlorine chemistry, temporary removal of HNO3 from the gas-phase (uptake), permanent removal of HNO3 from the atmosphere (denitrification), and chlorine activation through heterogeneous reactions. We have performed simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) employing a recently developed algorithm for saturation-dependent NAT nucleation for the Antarctic winters 2011 and 2012. The simulation results are compared with different satellite observations. With the help of these simulations, we investigate the role of the different processes responsible for chlorine activation and ozone depletion. Especially the sensitivity with respect to the particle type has been investigated. If temperatures are artificially forced to only allow cold binary liquid aerosol, the simulation still shows significant chlorine activation and ozone depletion. The results of the 3-D Chemical Transport Model CLaMS simulations differ from purely Lagrangian longtime trajectory box model simulations which indicates the importance of mixing processes.

  9. Characterization of human plasma proteome dynamics using deuterium oxide.

    PubMed

    Wang, Ding; Liem, David A; Lau, Edward; Ng, Dominic C M; Bleakley, Brian J; Cadeiras, Martin; Deng, Mario C; Lam, Maggie P Y; Ping, Peipei

    2014-08-01

    High-throughput quantification of human protein turnover via in vivo administration of deuterium oxide ((2) H2 O) is a powerful new approach to examine potential disease mechanisms. Its immediate clinical translation is contingent upon characterizations of the safety and hemodynamic effects of in vivo administration of (2) H2 O to human subjects. We recruited ten healthy human subjects with a broad demographic variety to evaluate the safety, feasibility, efficacy, and reproducibility of (2) H2 O intake for studying protein dynamics. We designed a protocol where each subject orally consumed weight-adjusted doses of 70% (2) H2 O daily for 14 days to enrich body water and proteins with deuterium. Plasma proteome dynamics was measured using a high-resolution MS method we recently developed. This protocol was successfully applied in ten human subjects to characterize the endogenous turnover rates of 542 human plasma proteins, the largest such human dataset to-date. Throughout the study, we did not detect physiological effects or signs of discomfort from (2) H2 O consumption. Our investigation supports the utility of a (2) H2 O intake protocol that is safe, accessible, and effective for clinical investigations of large-scale human protein turnover dynamics. This workflow shows promising clinical translational value for examining plasma protein dynamics in human diseases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Characterization of human plasma proteome dynamics using deuterium oxide

    PubMed Central

    Wang, Ding; Liem, David A; Lau, Edward; Ng, Dominic CM; Bleakley, Brian J; Cadeiras, Martin; Deng, Mario C; Lam, Maggie PY; Ping, Peipei

    2016-01-01

    Purpose High-throughput quantification of human protein turnover via in vivo administration of deuterium oxide (2H2O) is a powerful new approach to examine potential disease mechanisms. Its immediate clinical translation is contingent upon characterizations of the safety and hemodynamic effects of in vivo administration of 2H2O to human subjects. Experimental design We recruited 10 healthy human subjects with a broad demographic variety to evaluate the safety, feasibility, efficacy, and reproducibility of 2H2O intake for studying protein dynamics. We designed a protocol where each subject orally consumed weight-adjusted doses of 70% 2H2O daily for 14 days to enrich body water and proteins with deuterium. Plasma proteome dynamics was measured using a high-resolution MS method we recently developed. Results This protocol was successfully applied in 10 human subjects to characterize the endogenous turnover rates of 542 human plasma proteins, the largest such human dataset to-date. Throughout the study, we did not detect physiological effects or signs of discomfort from 2H2O consumption. Conclusions and clinical relevance Our investigation supports the utility of a 2H2O intake protocol that is safe, accessible, and effective for clinical investigations of large-scale human protein turnover dynamics. This workflow shows promising clinical translational value for examining plasma protein dynamics in human diseases. PMID:24946186

  11. 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

  12. Deuterium fractionation and H2D+ evolution in turbulent and magnetized cloud cores

    NASA Astrophysics Data System (ADS)

    Körtgen, Bastian; Bovino, Stefano; Schleicher, Dominik R. G.; Giannetti, Andrea; Banerjee, Robi

    2017-08-01

    High-mass stars are expected to form from dense prestellar cores. Their precise formation conditions are widely discussed, including their virial condition, which results in slow collapse for supervirial cores with strong support by turbulence or magnetic fields, or fast collapse for subvirial sources. To disentangle their formation processes, measurements of the deuterium fractions are frequently employed to approximately estimate the ages of these cores and to obtain constraints on their dynamical evolution. We here present 3D magnetohydrodynamical simulations including for the first time an accurate non-equilibrium chemical network with 21 gas-phase species plus dust grains and 213 reactions. With this network we model the deuteration process in fully depleted prestellar cores in great detail and determine its response to variations in the initial conditions. We explore the dependence on the initial gas column density, the turbulent Mach number, the mass-to-magnetic flux ratio and the distribution of the magnetic field, as well as the initial ortho-to-para ratio (OPR) of H2. We find qualitatively good agreement with recent observations of deuterium fractions in quiescent sources. Our results show that deuteration is rather efficient, even when assuming a conservative OPR of 3 and highly subvirial initial conditions, leading to large deuterium fractions already within roughly a free-fall time. We discuss the implications of our results and give an outlook to relevant future investigations.

  13. Oxygen-isotope composition of ground water and secondary minerals in Columbia Plateau basalts: implications for the paleohydrology of the Pasco Basin

    USGS Publications Warehouse

    Hearn, P.P.; Steinkampf, W.C.; Horton, D.G.; Solomon, G.C.; White, L.D.; Evans, J.R.

    1989-01-01

    Concentrations of 18O and deuterium in ground waters beneath the Hanford Reservation, Washington State, suggest that the meteoric waters recharging the basalt aquifers have been progressively depleted in these isotopes since at least Pleistocene time. This conclusion is supported by oxygen-isotope analyses of low-temperature secondary minerals filling vugs and fractures in the basalts, which are used to approximate the 18O content of ground water at the time the mineral assemblage formed. A fossil profile of ??18O values projected for ground water in a 1500 m vertical section beneath the reservation suggests that the vertical mixing of shallow and deep ground water indicated by present-day hydrochemical data was also occurring during Neogene time. These data also suggest that a unidirectional depletion of 18O and deuterium recorded in Pleistocene ground waters may have extended considerably further back in time. This shift is tentatively attributed to the orographic depletion of 18O associated with the progressive uplift of the Cascade Range since the middle Miocene. -Authors

  14. 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.

  15. Precision measures of the primordial deuterium abundance.

    NASA Astrophysics Data System (ADS)

    Cooke, R. J.; Pettini, M.; Jorgenson, R. A.; Murphy, M. T.; Steidel, C. C.

    Near-pristine damped Lyman-alpha systems (DLAs) are the ideal environments to measure the primordial abundance of deuterium. In this conference report, I summarise our ongoing research programme to obtain the most precise determination of the primordial deuterium abundance from five high redshift DLAs. From this sample, we derive (D/H)_p = (2.53±0.04)×105, corresponding to a baryon density 100 Omega_b ,0 h2 = 2.202±0.046 assuming the standard model of Big Bang Nucleosynthesis. This value is in striking agreement with that measured from the temperature fluctuations imprinted on the cosmic microwave background. Although we find no strong evidence for new physics beyond the standard model, this line of research shows great promise in the near-future, when the next generation 30+ m telescopes equipped with echelle spectrographs come online.

  16. 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. )

  17. Groundwater depletion embedded in international food trade.

    PubMed

    Dalin, Carole; Wada, Yoshihide; Kastner, Thomas; Puma, Michael J

    2017-03-29

    Recent hydrological modelling and Earth observations have located and quantified alarming rates of groundwater depletion worldwide. This depletion is primarily due to water withdrawals for irrigation, but its connection with the main driver of irrigation, global food consumption, has not yet been explored. Here we show that approximately eleven per cent of non-renewable groundwater use for irrigation is embedded in international food trade, of which two-thirds are exported by Pakistan, the USA and India alone. Our quantification of groundwater depletion embedded in the world's food trade is based on a combination of global, crop-specific estimates of non-renewable groundwater abstraction and international food trade data. A vast majority of the world's population lives in countries sourcing nearly all their staple crop imports from partners who deplete groundwater to produce these crops, highlighting risks for global food and water security. Some countries, such as the USA, Mexico, Iran and China, are particularly exposed to these risks because they both produce and import food irrigated from rapidly depleting aquifers. Our results could help to improve the sustainability of global food production and groundwater resource management by identifying priority regions and agricultural products at risk as well as the end consumers of these products.

  18. Groundwater Depletion Embedded in International Food Trade

    NASA Technical Reports Server (NTRS)

    Dalin, Carole; Wada, Yoshihide; Kastner, Thomas; Puma, Michael J.

    2017-01-01

    Recent hydrological modeling and Earth observations have located and quantified alarming rates of groundwater depletion worldwide. This depletion is primarily due to water withdrawals for irrigation, but its connection with the main driver of irrigation, global food consumption, has not yet been explored. Here we show that approximately eleven per cent of non-renewable groundwater use for irrigation is embedded in international food trade, of which two-thirds are exported by Pakistan, the USA and India alone. Our quantification of groundwater depletion embedded in the world's food trade is based on a combination of global, crop-specific estimates of non-renewable groundwater abstraction and international food trade data. A vast majority of the world's population lives in countries sourcing nearly all their staple crop imports from partners who deplete groundwater to produce these crops, highlighting risks for global food and water security. Some countries, such as the USA, Mexico, Iran and China, are particularly exposed to these risks because they both produce and import food irrigated from rapidly depleting aquifers. Our results could help to improve the sustainability of global food production and groundwater resource management by identifying priority regions and agricultural products at risk as well as the end consumers of these products.

  19. Groundwater depletion embedded in international food trade

    NASA Astrophysics Data System (ADS)

    Dalin, Carole; Wada, Yoshihide; Kastner, Thomas; Puma, Michael J.

    2017-03-01

    Recent hydrological modelling and Earth observations have located and quantified alarming rates of groundwater depletion worldwide. This depletion is primarily due to water withdrawals for irrigation, but its connection with the main driver of irrigation, global food consumption, has not yet been explored. Here we show that approximately eleven per cent of non-renewable groundwater use for irrigation is embedded in international food trade, of which two-thirds are exported by Pakistan, the USA and India alone. Our quantification of groundwater depletion embedded in the world’s food trade is based on a combination of global, crop-specific estimates of non-renewable groundwater abstraction and international food trade data. A vast majority of the world’s population lives in countries sourcing nearly all their staple crop imports from partners who deplete groundwater to produce these crops, highlighting risks for global food and water security. Some countries, such as the USA, Mexico, Iran and China, are particularly exposed to these risks because they both produce and import food irrigated from rapidly depleting aquifers. Our results could help to improve the sustainability of global food production and groundwater resource management by identifying priority regions and agricultural products at risk as well as the end consumers of these products.

  20. Desorption dynamics of deuterium in CuCrZr alloy

    NASA Astrophysics Data System (ADS)

    Thi Nguyen, Lan Anh; Lee, Sanghwa; Noh, S. J.; Lee, S. K.; Park, M. C.; Shu, Wataru; Pitcher, Spencer; Torcy, David; Guillermain, David; Kim, Jaeyong

    2017-12-01

    Desorption behavior of deuterium (D2) in CuCrZr alloy was investigated considering sample thickness, loading and baking temperature of deuterium followed by the ITER scopes. Cylindrical specimens of 1, 3, 5 mm thick with 4 mm diameter were exposed to deuterium at a pressure of 25 bar at 120, 240 and 350 °C for 24 h, then baked at 800 °C in a vacuum chamber maintained at a pressure lower than 10-7 Torr. Deuterium desorption characteristics such as desorption rate and amount of deuterium in the sample were estimated by analyzing the desorption peaks monitored with a residual gas analyzer (RGA), and the trapping energy of deuterium was calculated using thermal desorption spectroscopy (TDS). Secondary ion mass spectroscopy (SIMS) results showed that deuterium atoms embedded in the sample at a depth of less than 15 μm and desorbed as low as 400 °C. All absorbed deuterium atoms in the specimen were completely retrieved by dynamic pumping at 800 °C in 15 min. The desorption rate of deuterium per unit area was inversely proportional to the increment of the thickness of the sample, and was proportional to the loading temperature. Based on the assumption that a uniform distribution of interstitial sites for deuterium follows the Femi-Dirac statistics, the result of TDS demonstrated that the CuCrZr alloy has two types of trapping energies, which were estimated to be 62 and 79 kJ/mol.

  1. Effect of Water-Table Fluctuations on Source Depletion and Dissolved-Plume Behavior of a Multi-Component Light Nonaqueous-Phase Liquid

    NASA Astrophysics Data System (ADS)

    Dobson, R.; Schroth, M. H.; Zeyer, J.

    2006-12-01

    Light nonaqueous-phase liquids (LNAPLs) such as gasoline and diesel are among the most common soil and groundwater contaminants. Dissolution and subsequent advective transport of LNAPL components can negatively impact downgradient water supplies, while biodegradation is commonly thought to be an important sink for this class of contaminants. Water-table fluctuations, either naturally occurring or intentionally induced, may affect LNAPL component transport and biodegradation in aquifers. We present a laboratory investigation of the effect of water-table fluctuations on the dissolution and biodegradation of a multi-component LNAPL in a pair of similar model aquifers, one of which was subjected to a water-table fluctuation. Water-table fluctuation resulted in LNAPL and air entrapment below the water table, an increase in the vertical extent of LNAPL contamination and an increase in the volume of water passing through the contaminated zone. Effluent concentrations of dissolved LNAPL components were higher and those of dissolved nitrate were lower in the aquifer model where a fluctuation had been induced. Thus, water table fluctuation led to enhanced LNAPL dissolution as well as enhanced biodegradation activity. The increase in biodegradation observed after fluctuation was of lesser magnitude than the increase in LNAPL dissolution, such that water-table fluctuations might be expected to result in increased exposure of downgradient receptors to dissolved LNAPL components. Conversely, the potential for free-phase LNAPL migration was reduced following a water-table fluctuation, as LNAPL entrapment by the rising water table reduced the amount of free phase LNAPL. Lateral migration of LNAPL following emplacement was observed in the model aquifer where no fluctuation occurred, but not in the model aquifer where a water-table fluctuation was induced.

  2. Tank depletion flow controller

    DOEpatents

    Georgeson, Melvin A.

    1976-10-26

    A flow control system includes two bubbler tubes installed at different levels within a tank containing such as radioactive liquid. As the tank is depleted, a differential pressure transmitter monitors pressure differences imparted by the two bubbler tubes at a remote, shielded location during uniform time intervals. At the end of each uniform interval, balance pots containing a dense liquid are valved together to equalize the pressures. The resulting sawtooth-shaped signal generated by the differential pressure transmitter is compared with a second sawtooth signal representing the desired flow rate during each time interval. Variations in the two signals are employed by a control instrument to regulate flow rate.

  3. Creation of deuterium protective layer below the tungsten surface

    NASA Astrophysics Data System (ADS)

    Krstic, Predrag; Kaganovich, Igor; Startsev, Edward

    2014-10-01

    By cumulative irradiation of both pre-damaged and virgin surfaces of monocrystal tungsten by deuterium atoms of impact energy of few tens of eV, we simulate by classical molecular dynamics the creation of a deuterium protective layer. The depth and width of the layer depend on the deuterium impact energy and the diffusion rate of deuterium in tungsten, the latter being influenced by the tungsten temperature and damage. Found simulation results are in concert with the experimental results, found recently in DIFFER. Support of the PPPL LDRD project acknowledged.

  4. Groundwater Depletion in the Middle East from GRACE with Implications for Transboundary Water Management in the Tigris-Euphrates-Western Iran Region

    NASA Technical Reports Server (NTRS)

    Voss, Katalyn A.; Famiglietti, James S.; Lo, MinHui; De Linage, Caroline; Rodell, Matthew; Swenson, Sean C.

    2013-01-01

    In this study, we use observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission to evaluate freshwater storage trends in the north-central Middle East, including portions of the Tigris and Euphrates River Basins and western Iran, from January 2003 to December 2009. GRACE data show an alarming rate of decrease in total water storage of approximately -27.2 plus or minus 0.6 millimeters per year equivalent water height, equal to a volume of 143.6 cubic kimometers during the course of the study period. Additional remote-sensing information and output from land surface models were used to identify that groundwater losses are the major source of this trend. The approach used in this study provides an example of ''best current capabilities'' in regions like the Middle East, where data access can be severely limited. Results indicate that the region lost 17.3 plus or minus 2.1 millimeters per year equivalent water height of groundwater during the study period, or 91.3 plus or minus 10.9 cubic kilometers in volume. Furthermore, results raise important issues regarding water use in transboundary river basins and aquifers, including the necessity of international water use treaties and resolving discrepancies in international water law, while amplifying the need for increased monitoring for core components of the water budget.

  5. Groundwater Depletion in the Middle East from GRACE with Implications for Transboundary Water Management in the Tigris-Euphrates-Western Iran Region

    NASA Technical Reports Server (NTRS)

    Voss, Katalyn; Famiglietti, James S.; Lo, MinHui; de Linage, Caroline; Rodell, Matthew; Swenson, Sean C.

    2013-01-01

    In this study, we use observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission to evaluate freshwater storage trends in the north-central Middle East, including portions of the Tigris and Euphrates River Basins and western Iran, from January 2003 to December 2009. GRACE data show an alarming rate of decrease in total water storage of approximately -27.2 plus or minus 0.6 mm per yr equivalent water height, equal to a volume of 143.6 cubic kilometers during the course of the study period. Additional remote-sensing information and output from land surface models were used to identify that groundwater losses are the major source of this trend. The approach used in this study provides an example of ''best current capabilities'' in regions like the Middle East, where data access can be severely limited. Results indicate that the region lost 17.3 plus or minus 2.1 mm per yr equivalent water height of groundwater during the study period, or 91.3 plus or minus 10.9 cubic kilometers in volume. Furthermore, results raise important issues regarding water use in transboundary river basins and aquifers, including the necessity of international water use treaties and resolving discrepancies in international water law, while amplifying the need for increased monitoring for core components of the water budget

  6. Groundwater depletion in the Middle East from GRACE with implications for transboundary water management in the Tigris-Euphrates-Western Iran region

    NASA Astrophysics Data System (ADS)

    Voss, Katalyn A.; Famiglietti, James S.; Lo, MinHui; de Linage, Caroline; Rodell, Matthew; Swenson, Sean C.

    2013-02-01

    In this study, we use observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission to evaluate freshwater storage trends in the north-central Middle East, including portions of the Tigris and Euphrates River Basins and western Iran, from January 2003 to December 2009. GRACE data show an alarming rate of decrease in total water storage of approximately -27.2±0.6 mm yr-1 equivalent water height, equal to a volume of 143.6 km3 during the course of the study period. Additional remote-sensing information and output from land surface models were used to identify that groundwater losses are the major source of this trend. The approach used in this study provides an example of "best current capabilities" in regions like the Middle East, where data access can be severely limited. Results indicate that the region lost 17.3±2.1 mm yr-1 equivalent water height of groundwater during the study period, or 91.3±10.9 km3 in volume. Furthermore, results raise important issues regarding water use in transboundary river basins and aquifers, including the necessity of international water use treaties and resolving discrepancies in international water law, while amplifying the need for increased monitoring for core components of the water budget.

  7. Geochemistry of thermal water from selected wells, Boise, Idaho

    USGS Publications Warehouse

    Mariner, R.H.; Young, H.W.; Parliman, D.J.; Evans, William C.

    1989-01-01

    Samples of thermal water from selected wells in the Boise area were analyzed for chemical composition; stable isotopes of hydrogen, oxygen, and dissolved carbon; radioactive carbon; and dissolved-gas concentrations. Chemically, the waters are virtually identical to those of the adjacent Idaho batholith. Isotopically, the thermal waters are more depleted in deuterium and oxygen-18 than coldwater springs in the presumed recharge area. Chemical and isotopic data indicate the presence of two separate geothermal systems. Radioactive carbon and dissolved helium concentrations are interpreted to indicate recharge during the Pleistocene. Hot water in or southeast of Boise probably recharged 20,000 to 30,000 years ago, and warm water 2.5 miles northwest of Boise probably recharged at least 15,000 years ago.

  8. Hydrogen/deuterium exchange in mass spectrometry.

    PubMed

    Kostyukevich, Yury; Acter, Thamina; Zherebker, Alexander; Ahmed, Arif; Kim, Sunghwan; Nikolaev, Eugene

    2018-03-30

    The isotopic exchange approach is in use since the first observation of such reactions in 1933 by Lewis. This approach allows the investigation of the pathways of chemical and biochemical reactions, determination of structure, composition, and conformation of molecules. Mass spectrometry has now become one of the most important analytical tools for the monitoring of the isotopic exchange reactions. Investigation of conformational dynamics of proteins, quantitative measurements, obtaining chemical, and structural information about individual compounds of the complex natural mixtures are mainly based on the use of isotope exchange in combination with high resolution mass spectrometry. The most important reaction is the Hydrogen/Deuterium exchange, which is mainly performed in the solution. Recently we have developed the approach allowing performing of the Hydrogen/Deuterium reaction on-line directly in the ionization source under atmospheric pressure. Such approach simplifies the sample preparation and can accelerate the exchange reaction so that certain hydrogens that are considered as non-labile will also participate in the exchange. The use of in-ionization source H/D exchange in modern mass spectrometry for structural elucidation of molecules serves as the basic theme in this review. We will focus on the mechanisms of the isotopic exchange reactions and on the application of in-ESI, in-APCI, and in-APPI source Hydrogen/Deuterium exchange for the investigation of petroleum, natural organic matter, oligosaccharides, and proteins including protein-protein complexes. The simple scenario for adaptation of H/D exchange reactions into mass spectrometric method is also highlighted along with a couple of examples collected from previous studies. © 2018 Wiley Periodicals, Inc.

  9. Groundwater depletion in the United States (1900−2008)

    USGS Publications Warehouse

    Konikow, Leonard F.

    2013-01-01

    A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion in the United States are not well characterized. This study evaluates long-term cumulative depletion volumes in 40 separate aquifers or areas and one land use category in the United States, bringing together information from the literature and from new analyses. Depletion is directly calculated using calibrated groundwater models, analytical approaches, or volumetric budget analyses for multiple aquifer systems. Estimated groundwater depletion in the United States during 1900–2008 totals approximately 1,000 cubic kilometers (km3). Furthermore, the rate of groundwater depletion has increased markedly since about 1950, with maximum rates occurring during the most recent period (2000–2008) when the depletion rate averaged almost 25 km3 per year (compared to 9.2 km3 per year averaged over the 1900–2008 timeframe).

  10. Erosion and deuterium retention of CLF-1 steel exposed to deuterium plasma

    NASA Astrophysics Data System (ADS)

    Qiao, L.; Wang, P.; Hu, M.; Gao, L.; Jacob, W.; Fu, E. G.; Luo, G. N.

    2017-12-01

    In recent years reduced activation ferritic martensitic steel has been proposed as the plasma-facing material in remote regions of the first wall. This study reports the erosion and deuterium retention behaviours in CLF-1 steel exposed to deuterium (D) plasma in a linear experimental plasma system as function of incident ion energy and fluence. The incident D ion energy ranges from 30 to 180 eV at a flux of 4 × 1021 D m-2 s-1 up to a fluence of 1025 D m-2. SEM images revealed a clear change of the surface morphology as functions of incident fluence and impinging energy. The mass loss results showed a decrease of the total sputtering yield of CLF-1 steel with increasing incident fluence by up to one order of magnitude. The total sputtering yield of CLF-1 steel after 7.2 × 1024 D m-2 deuterium plasma exposure reduced by a factor of 4 compared with that of pure iron, which can be attributed to the enrichment of W at the surface due to preferential sputtering of iron and chromium. After D plasma exposure, the total deuterium retention in CLF-1 steel samples measured by TDS decreased with increasing incident fluence and energy, and a clear saturation tendency as function of incident fluence or energy was also observed.

  11. Observations of Highly Variable Deuterium in the Martian Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Clarke, John T.; Mayyasi-Matta, Majd A.; Bhattacharyya, Dolon; Chaufray, Jean-Yves; Chaffin, Michael S.; Deighan, Justin; Schneider, Nicholas M.; Jain, Sonal; Jakosky, Bruce

    2017-10-01

    One of the key pieces of evidence for historic high levels of water on Mars is the present elevated ratio of deuterium/hydrogen (D/H) in near-surface water. This can be explained by the loss of large amounts of water into space, with the lighter H atoms escaping faster than D atoms. Understanding the specific physical processes and controlling factors behind the present escape of H and D is the key objective of the MAVEN IUVS echelle channel. This knowledge can then be applied to an accurate extrapolation back in time to understand the water history of Mars. Observations of D in the martian upper atmosphere over the first martian year of the MAVEN mission have shown highly variable amounts of D, with a short-lived maximum just after perihelion and during southern summer. The timing and nature of this increase provide constraints on its possible origin. These results will be presented and compared with other measurements of the upper atmosphere of Mars.

  12. The production rate of cosmogenic deuterium at the Moon's surface

    NASA Astrophysics Data System (ADS)

    Füri, Evelyn; Deloule, Etienne; Trappitsch, Reto

    2017-09-01

    The hydrogen (D/H) isotope ratio is a key tracer for the source of planetary water. However, secondary processes such as solar wind implantation and cosmic ray induced spallation reactions have modified the primordial D/H signature of 'water' in all rocks and soils recovered on the Moon. Here, we re-evaluate the production rate of cosmogenic deuterium (D) at the Moon's surface through ion microprobe analyses of hydrogen isotopes in olivines from eight Apollo 12 and 15 mare basalts. These in situ measurements are complemented by CO2 laser extraction-static mass spectrometry analyses of cosmogenic noble gas nuclides (3He, 21Ne, 38Ar). Cosmic ray exposure (CRE) ages of the mare basalts, derived from their cosmogenic 21Ne content, range from 60 to 422 Ma. These CRE ages are 35% higher, on average, than the published values for the same samples. The amount of D detected in the olivines increases linearly with increasing CRE ages, consistent with a production rate of (2.17 ± 0.11) ×10-12 mol(g rock)-1 Ma-1. This value is more than twice as high as previous estimates for the production of D by galactic cosmic rays, indicating that for water-poor lunar samples, i.e., samples with water concentrations ≤50 ppm, corrected D/H ratios have been severely overestimated.

  13. Deuterium chemistry in the young massive protostellar core NGC 2264 CMM3

    NASA Astrophysics Data System (ADS)

    Awad, Z.; Shalabiea, O. M.

    2018-01-01

    In this work we present the first attempt of modelling the deuterium chemistry in the massive young protostellar core NGC 2264 CMM3. We investigated the sensitivity of this chemistry to the physical conditions in its surrounding environment. The results showed that deuteration, in the protostellar gas, is affected by variations in the core density, the amount of gas depletion onto grain surfaces, the CR ionisation rate, but it is insensitive to variations in the H2 ortho-to-para ratio. Our results, also, showed that deuteration is often enhanced in less-dense, partially depleted (<85%), or cores that are exerted to high CR ionisation rates (≥6.5×10^{-17} s^{-1}). However, in NGC 2264 CMM3, decreasing the amount of gas depleted onto grains and enhancing the CR ionisation rate are often overestimating the observed values in the core. The best fit time to observations occurs around (1-5) × 104 yrs for core densities in the range (1-5)×106 cm^{-3} with CR ionisation rate between (1.7-6.5)×10^{-17} s^{-1}. These values are in agreement with the results of the most recent theoretical chemical model of CMM3, and the time range of best fit is, also, in-line with the estimated age of young protostellar objects. We conclude that deuterium chemistry in protostellar cores is: (i) sensitive to variations in the physical conditions in its environment, (ii) insensitive to changes in the H2 ortho-to-para ratio. We also conclude that the core NGC 2264 CMM3 is in its early stages of chemical evolution with an estimated age of (1-5)×104 yrs.

  14. CO Depletion: A Microscopic Perspective

    SciTech Connect

    Cazaux, S.; Martín-Doménech, R.; Caro, G. M. Muñoz

    In regions where stars form, variations in density and temperature can cause gas to freeze out onto dust grains forming ice mantles, which influences the chemical composition of a cloud. The aim of this paper is to understand in detail the depletion (and desorption) of CO on (from) interstellar dust grains. Experimental simulations were performed under two different (astrophysically relevant) conditions. In parallel, Kinetic Monte Carlo simulations were used to mimic the experimental conditions. In our experiments, CO molecules accrete onto water ice at temperatures below 27 K, with a deposition rate that does not depend on the substrate temperature.more » During the warm-up phase, the desorption processes do exhibit subtle differences, indicating the presence of weakly bound CO molecules, therefore highlighting a low diffusion efficiency. IR measurements following the ice thickness during the TPD confirm that diffusion occurs at temperatures close to the desorption. Applied to astrophysical conditions, in a pre-stellar core, the binding energies of CO molecules, ranging between 300 and 850 K, depend on the conditions at which CO has been deposited. Because of this wide range of binding energies, the depletion of CO as a function of A{sub V} is much less important than initially thought. The weakly bound molecules, easily released into the gas phase through evaporation, change the balance between accretion and desorption, which result in a larger abundance of CO at high extinctions. In addition, weakly bound CO molecules are also more mobile, and this could increase the reactivity within interstellar ices.« less

  15. Detection of Deuterium in Icy Surfaces and the D/H Ratio of Icy Objects

    NASA Astrophysics Data System (ADS)

    Clark, Roger Nelson; Brown, Robert H.; Swayze, Gregg A.; Cruikshank, Dale P.

    2017-10-01

    Water ice in crystalline or amorphous form is orientationally disordered, which results in very broad absorptions. Deuterium in trace amounts goes into an ordered position, so is not broadened like H2O absorptions. The D-O stretch is located at 4.13 microns with a width of 0.027 micron. Laboratory spectral measurements on natural H2O and deuterium doped ice show the absorption is slightly asymmetric and in reflectance the band shifts from 4.132 to 4.137 microns as abundance decreases. We derive a preliminary absorption coefficient of ~ 80,000 cm^-1 for the D-O stretch compared to about 560 cm^-1 in H2O ice at 4.13 microns, enabling the detection of deuterium at levels less than Vienna Standard Mean Ocean Water (VSMOW), depending on S/N. How accurate the D/H ratios can be derived will require additional lab work and radiative transfer modeling to simultaneously derive the grain size distribution, the abundance of any contaminants, and deuterium abundance. To first order, the grain size distribution can be compensated by computing the D-O stretch band depth to 2-micron H2O ice band depth ratio, which we call Dratio. Colorado fresh water (~80% of VSMOW) has a Dratio of 0.036, at a D/H = 0.0005, the Dratio = 0.15, and at a D/H = 0.0025, the Dratio = 0.42. The VSMOW Dratio is ~ 0.045.We have used VIMS data from the Cassini spacecraft to compute large spectral averages to detect the deuterium in the rings and on the icy satellite surfaces. A B-ring, 21,882 pixel average, at 640 ms/pixel, or 3.89 hours of integration time, shows a 3.5% O-D stretch band depth and a Dratio = 0.045, indicating deuterium abundance equal to VSMOW. Rhea, using 1.89 hours of integration time shows Dratio = 0.052, or slightly higher than VSMOW. Phoebe has an unusually deep O-D stretch band of 1.85% considering the high abundance of dark material suppressing the ice absorptions. We measure a Dratio = 0.11, an enhancement of ~2.4 over VSMOW, but detailed radiative transfer modeling is needed to

  16. Is High Primordial Deuterium Consistent with Galactic Evolution?

    NASA Astrophysics Data System (ADS)

    Tosi, Monica; Steigman, Gary; Matteucci, Francesca; Chiappini, Cristina

    1998-05-01

    Galactic destruction of primordial deuterium is inevitably linked through star formation to the chemical evolution of the Galaxy. The relatively high present gas content and low metallicity suggest only modest D destruction. In concert with deuterium abundances derived from solar system and/or interstellar observations, this suggests a primordial deuterium abundance in possible conflict with data from some high-redshift, low-metallicity QSO absorbers. We have explored a variety of chemical evolution models including infall of processed material and early, supernovae-driven winds with the aim of identifying models with large D destruction that are consistent with the observations of stellar-produced heavy elements. When such models are confronted with data, we reconfirm that only modest destruction of deuterium (less than a factor of 3) is permitted. When combined with solar system and interstellar data, these results favor the low deuterium abundances derived for the QSO absorbers by Tytler et al.

  17. The production rate of cosmogenic deuterium at the Moon's surface

    DOE PAGES

    Füri, Evelyn; Deloule, Etienne; Trappitsch, Reto

    2017-07-03

    The hydrogen (D/H) isotope ratio is a key tracer for the source of planetary water. However, secondary processes such as solar wind implantation and cosmic ray induced spallation reactions have modified the primordial D/H signature of ‘water’ in all rocks and soils recovered on the Moon. We re-evaluate the production rate of cosmogenic deuterium (D) at the Moon's surface through ion microprobe analyses of hydrogen isotopes in olivines from eight Apollo 12 and 15 mare basalts. Furthermore, these in situ measurements are complemented by CO2 laser extraction-static mass spectrometry analyses of cosmogenic noble gas nuclides ( 3He, 21Ne, 38Ar). Cosmicmore » ray exposure (CRE) ages of the mare basalts, derived from their cosmogenic 21Ne content, range from 60 to 422 Ma. These CRE ages are 35% higher, on average, than the published values for the same samples. The amount of D detected in the olivines increases linearly with increasing CRE ages, consistent with a production rate of (2.17±0.11)×10 -12 mol(g rock) -1 Ma -1. This value is more than twice as high as previous estimates for the production of D by galactic cosmic rays, indicating that for water-poor lunar samples, i.e., samples with water concentrations ≤50 ppm, corrected D/H ratios have been severely overestimated.« less

  18. Influence of Water with Modified Isotope Structure on Development of Radiation Damage in Experimental Animals

    NASA Astrophysics Data System (ADS)

    Rakov, D. V.; Fedorenko, B. S.; Sinyak, Yu. E.

    begin table htbp begin center begin tabular p 442pt hline As the duration of space missions increases the problem of durability of space crews and their resistivity to space flight factors becomes more important The purpose of the present work was to study the radioprotective effects of lowered deuterium content water in experimental animals after repeated exposures to low doses of gamma radiation Both male and female adult mice of NAAoN57Al6 F1 and BALB c lines were exposed to 0 25 0 5 and 1 0 Gy of 60 Co gamma rays by multiple fractions The dose rate was 0 32 Gy min Starting from one month prior to the first irradiation fraction till the end of the experiment the animals were only supplied with lowered deuterium content water ad libitum The control group of mice consumed tap water only The mice were sacrificed by means of cervical dislocation within one month after finishing the last irradiation fraction The following parameters were registered the weight of body thymus and spleen number of leucocytes blood formula number of caryocytes in femur bone marrow cytogenetic lesions in nucleated bone marrow cells The water with lowered deuterium content was produced by means of electrolysis with a special device in the Institute for Biomedical Problems par A long-term consumption of water with lowered deuterium content by irradiated mice was found to result in lower levels of depletion of peripheral blood leucocytes and bone marrow cells in a decrease in the yield of cytogenetic aberrations and in a less intensive reduction of the mass

  19. 12. VIEW OF DEPLETED URANIUM INGOT AND MOLDS. DEPLETED URANIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW OF DEPLETED URANIUM INGOT AND MOLDS. DEPLETED URANIUM CASTING OPERATIONS CEASED IN 1988. (11/14/57) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

  20. SAR interferometry monitoring of subsidence in a detritic basin related to water depletion in the underlying confined carbonate aquifer (Torremolinos, southern Spain).

    PubMed

    Ruiz-Constán, A; Ruiz-Armenteros, A M; Martos-Rosillo, S; Galindo-Zaldívar, J; Lazecky, M; García, M; Sousa, J J; Sanz de Galdeano, C; Delgado-Blasco, J M; Jiménez-Gavilán, P; Caro-Cuenca, M; Luque-Espinar, J A

    2018-09-15

    This research underlines the need to improve water management policies for areas linked to confined karstic aquifers subjected to intensive exploitation, and to develop additional efforts towards monitoring their subsidence evolution. We analyze subsidence related to intensive use of groundwater in a confined karstic aquifer, through the use of the InSAR technique, by the southern coast of Spain (Costa del Sol). Carbonates are overlain by an unconfined detritic aquifer with interlayered high transmissivity rocks, in connection with the Mediterranean Sea, where the water level is rather stable. Despite this, an accumulated deformation in the line-of-sight (LOS) direction greater than -100 mm was observed by means of the ERS-1/2 (1992-2000) and Envisat (2003-2009) satellite SAR sensors. During this period, the Costa del Sol experienced a major population increase due to the expansion of the tourism industry, with the consequent increase in groundwater exploitation. The maximum LOS displacement rates recorded during both time spans are respectively -6 mm/yr and -11 mm/yr, respectively. During the entire period, there was an accumulated descent of the confined water level of 140 m, and several fluctuations of more than 80 m correlating with the subsidence trend observed for the whole area. Main sedimentary depocenters (up to 800 m), revealed by gravity prospecting, partly coincide with areas of subsidence maxima; yet ground deformation is also influenced by other factors, the main ones being the fine-grained facies distribution and rapid urbanization due to high touristic pressure. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. 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

  2. Nuclear Fuel Depletion Analysis Using Matlab Software

    NASA Astrophysics Data System (ADS)

    Faghihi, F.; Nematollahi, M. R.

    Coupled first order IVPs are frequently used in many parts of engineering and sciences. In this article, we presented a code including three computer programs which are joint with the Matlab software to solve and plot the solutions of the first order coupled stiff or non-stiff IVPs. Some engineering and scientific problems related to IVPs are given and fuel depletion (production of the 239Pu isotope) in a Pressurized Water Nuclear Reactor (PWR) are computed by the present code.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Deuterium permeation through EPDM rubber compounds

    SciTech Connect

    Zapp, P.E.

    1988-01-01

    The permeation of deuterium through a specially formulated compound of ethylene propylene diene rubber was measured in the temperature range of 26/degree/C to 120/degree/C. The results were similar to permeation through two commercial compounds of this elastomer. Permeation was reduced after gamma irradiation (in the presence of hydrogen gas to simulate a tritium exposure). However the reduction was smaller than that experienced by the two commercial compounds. Radiation damage is apparently less severe in the special compound. It is possible that mechanical properties such as compression set may be influenced less by ionizing radiation in this compound as compared withmore » the commercial compounds. 4 figs., 1 tab.« less

  8. Ego depletion impairs implicit learning.

    PubMed

    Thompson, Kelsey R; Sanchez, Daniel J; Wesley, Abigail H; Reber, Paul J

    2014-01-01

    Implicit skill learning occurs incidentally and without conscious awareness of what is learned. However, the rate and effectiveness of learning may still be affected by decreased availability of central processing resources. Dual-task experiments have generally found impairments in implicit learning, however, these studies have also shown that certain characteristics of the secondary task (e.g., timing) can complicate the interpretation of these results. To avoid this problem, the current experiments used a novel method to impose resource constraints prior to engaging in skill learning. Ego depletion theory states that humans possess a limited store of cognitive resources that, when depleted, results in deficits in self-regulation and cognitive control. In a first experiment, we used a standard ego depletion manipulation prior to performance of the Serial Interception Sequence Learning (SISL) task. Depleted participants exhibited poorer test performance than did non-depleted controls, indicating that reducing available executive resources may adversely affect implicit sequence learning, expression of sequence knowledge, or both. In a second experiment, depletion was administered either prior to or after training. Participants who reported higher levels of depletion before or after training again showed less sequence-specific knowledge on the post-training assessment. However, the results did not allow for clear separation of ego depletion effects on learning versus subsequent sequence-specific performance. These results indicate that performance on an implicitly learned sequence can be impaired by a reduction in executive resources, in spite of learning taking place outside of awareness and without conscious intent.

  9. The Toxicity of Depleted Uranium

    PubMed Central

    Briner, Wayne

    2010-01-01

    Depleted uranium (DU) is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a clear and defined set of symptoms. Chronic low-dose, or subacute, exposure to depleted uranium alters the appearance of milestones in developing organisms. Adult animals that were exposed to depleted uranium during development display persistent alterations in behavior, even after cessation of depleted uranium exposure. Adult animals exposed to depleted uranium demonstrate altered behaviors and a variety of alterations to brain chemistry. Despite its reduced level of radioactivity evidence continues to accumulate that depleted uranium, if ingested, may pose a radiologic hazard. The current state of knowledge concerning DU is discussed. PMID:20195447

  10. 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.

  11. Stratospheric ozone depletion

    PubMed Central

    Rowland, F. Sherwood

    2006-01-01

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294

  12. 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.

  13. Transequatorial Propagation and Depletion Precursors

    NASA Astrophysics Data System (ADS)

    Miller, E. S.; Bust, G. S.; Kaeppler, S. R.; Frissell, N. A.; Paxton, L. J.

    2014-12-01

    The bottomside equatorial ionosphere in the afternoon and evening sector frequently evolves rapidly from smoothly stratified to violently unstable with large wedges of depleted plasma growing through to the topside on timescales of a few tens of minutes. These depletions have numerous practical impacts on radio propagation, including amplitude scintillation, field-aligned irregularity scatter, HF blackouts, and long-distance transequatorial propagation at frequencies above the MUF. Practical impacts notwithstanding, the pathways and conditions under which depletions form remain a topic of vigorous inquiry some 80 years after their first report. Structuring of the pre-sunset ionosphere---morphology of the equatorial anomalies and long-wavelength undulations of the isodensity contours on the bottomside---are likely to hold some clues to conditions that are conducive to depletion formation. The Conjugate Depletion Experiment is an upcoming transequatorial forward-scatter HF/VHF experiment to investigate pre-sunset undulations and their connection with depletion formation. We will present initial results from the Conjugate Depletion Experiment, as well as a companion analysis of a massive HF propagation data set.

  14. Testing fully depleted CCD

    NASA Astrophysics Data System (ADS)

    Casas, Ricard; Cardiel-Sas, Laia; Castander, Francisco J.; Jiménez, Jorge; de Vicente, Juan

    2014-08-01

    The focal plane of the PAU camera is composed of eighteen 2K x 4K CCDs. These devices, plus four spares, were provided by the Japanese company Hamamatsu Photonics K.K. with type no. S10892-04(X). These detectors are 200 μm thick fully depleted and back illuminated with an n-type silicon base. They have been built with a specific coating to be sensitive in the range from 300 to 1,100 nm. Their square pixel size is 15 μm. The read-out system consists of a Monsoon controller (NOAO) and the panVIEW software package. The deafualt CCD read-out speed is 133 kpixel/s. This is the value used in the calibration process. Before installing these devices in the camera focal plane, they were characterized using the facilities of the ICE (CSIC- IEEC) and IFAE in the UAB Campus in Bellaterra (Barcelona, Catalonia, Spain). The basic tests performed for all CCDs were to obtain the photon transfer curve (PTC), the charge transfer efficiency (CTE) using X-rays and the EPER method, linearity, read-out noise, dark current, persistence, cosmetics and quantum efficiency. The X-rays images were also used for the analysis of the charge diffusion for different substrate voltages (VSUB). Regarding the cosmetics, and in addition to white and dark pixels, some patterns were also found. The first one, which appears in all devices, is the presence of half circles in the external edges. The origin of this pattern can be related to the assembly process. A second one appears in the dark images, and shows bright arcs connecting corners along the vertical axis of the CCD. This feature appears in all CCDs exactly in the same position so our guess is that the pattern is due to electrical fields. Finally, and just in two devices, there is a spot with wavelength dependence whose origin could be the result of a defectous coating process.

  15. Regulation of Isotopic Composition of Water - way of Improvement of Cosmonauts Drinking Water Functional Properties

    NASA Astrophysics Data System (ADS)

    Kulikova, Ekaterina; Utina, Dina; Vorozhtsova, Svetlana; Severyuhin, Yuri; Abrosimova, Anna; Sinyak, Yuri; Ivanov, Alexander

    The problem in providing drinking water to cosmonauts is solved - at this moment there is a task to improve the functional properties of the water. One of the perspectives of this trend is the use of light isotopic water. The animal studies have shown that long-term consumption of water with a depletion of deuterium and oxygen heavy isotopes accelerates the rise of mass non-irradiated mice, the phase fluctuations reducing or increasing hematological parameters were having adaptive nature. These fluctuations didn’t overcome values beyond the physiological norm of this type of animal. It is established that the therapeutic use of light isotopic water with 35 - 90 ppm in deuterium increases the survival of irradiated mice by an average of 30%, contributes to the preservation of irradiated animals body weight. Treatment of acute radiation sickness with light isotopic water stimulates hematopoietic recovery. At the same time, keeping mice drinking light isotopic water for 7 - 8 days before the irradiation (from 4 to 8.5 Gr) has no effect on the level of radio resistance. Longer keeping mice on light isotopic water, for 14 -21 days - reduction in life expectancy, animal mass, bone marrow cellularity and the level of white blood cells in irradiated animals is noted. It was established that keeping mice on light isotopic water for 14 days before exposure in experimental animals causes an increase in the mitotic index and the frequency of formation of aberrant mitosis after 24 hours of Co(60) gamma radiation in doses of 1 , 2, and 4 Gr. Thus, it is clear that the regulation of the isotopic composition of drinking water - way to improve its functional properties.

  16. 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.

  17. Synthesis of deuterium labeled ketamine metabolite dehydronorketamine-d₄.

    PubMed

    Sulake, Rohidas S; Chen, Chinpiao; Lin, Huei-Ru; Lua, Ahai-Chang

    2011-10-01

    A convenient synthesis of ketamine metabolite dehydronorketamine-d(4), starting from commercially available deuterium labeled bromochlorobenzene, was achieved. Key steps include Grignard reaction, regioselective hydroxybromination, Staudinger reduction, and dehydrohalogenation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Extending the application of deuterium excess as a tracer in surface and groundwaters

    NASA Astrophysics Data System (ADS)

    Hurst, S.; Krishnamurthy, R. V.

    2017-12-01

    Stable isotopes of surface and ground waters provide invaluable information on the processes involved in their genesis. A starting point in these applications is the relationship between hydrogen (δ2H) and oxygen (δ18O), exemplified in the so-called Global Meteoric Water Line where δ2H=8δ18O+10 [1]. From this line Dansgaard [2] defined the parameter deuterium excess where d=δ2H-8δ18O. Generally, the d-excess value is fixed at the source, predominantly the equatorial oceans and retained. At an average humidity of about 85% the expected d-excess value is 10. Deviations indicate secondary changes in the air mass or a water body thus making d-excess a useful geophysical tracer. For instance, evaporation results in a higher d-excess in the vapor. Mixing of this water vapor with overhead air mass results in precipitation exhibiting d-excess values higher than Global Meteoric Water Line [3]. Alternatively, the fraction of liquid remaining will have low d-excess and in extreme cases negative d-excess. In this case a plot of d-excess-δ2H will give a straight line with a negative slope. This can be demonstrated from pan evaporation experiments [4]. Deviation from a perfect straight line on the d-excess-δ2H plot indicates a combination of mixing from various source waters and evaporation. This study will discuss various case studies from multiple environments applying this approach using d-excess. References [1] Craig, H. Standard for Reporting Concentrations of Deuterium and Oxygen-18 in Natural Waters. Science 133, 1833-1834 (1961). [2] Dansgaard, W. Stable isotopes in precipitation. Tellus A 16: 436-468 (1964). [3] Machavaram, M. &, Krishnamurthy, R.V. Earth surface evaporative process: a case study from the Great Lakes region of the United States based on deuterium excess in precipitation. Geochim. et Cosmochem. Acta 59, 4279-4283 (1995). [4] Simpson, H.J., Hamza, M.S., & White, J.W.C. Evaporative enrichment of deuterium and 18O in arid zone irrigation. IAEA, 241

  19. Deuterium-lithium plasma as a source of fusion neutrons

    NASA Astrophysics Data System (ADS)

    Chirkov, A. Yu; Vesnin, V. R.

    2017-11-01

    The concepts of deuterium-tritium (D-T) fusion neutron source are currently developed for hybrid fusion-fission systems and the waste transmutation ones. The need to use tritium technologies is a deterrent factor in this promising direction of energy production. Potential possibilities of using systems that do not require tritium developments are of a significant interest. A deuterium-deuterium (D-D) reaction is considered for the use in demonstration fusion neutron sources. The product of this reaction is tritium, which will burn in the plasma with the emission of fast neutrons. D-D reaction is significantly slower then D-T reaction. Present study shows an increase in neutron yield using a powerful injection of the beam of deuterium atoms. The reactions of the deuterium with lithium isotopes are considered. In some of these reactions, fast neutrons can be obtained. The results of the calculation of the neutron yield from the deuterium lithium plasma are discussed. The estimates of the parameters needed for the realization of a source of fusion neutrons are presented.

  20. Implanted Deuterium Retention and Release in Carbon-Coated Beryllium

    NASA Astrophysics Data System (ADS)

    Anderl, R. A.; Longhurst, G. R.; Pawelko, R. J.; Oates, M. A.

    1997-06-01

    Deuterium implantation experiments have been conducted on samples of clean and carbon-coated beryllium. These studies entailed preparation and characterization of beryllium samples coated with carbon thicknesses of 100, 500, and 1000 Å. Heat treatment of a beryllium sample coated with carbon to a thickness of approximately 100 Å revealed that exposure to a temperature of 400°C under high vacuum conditions was sufficient to cause substantial diffusion of beryllium through the carbon layer, resulting in more beryllium than carbon at the surface. Comparable concentrations of carbon and beryllium were observed in the bulk of the coating layer. Higher than expected oxygen levels were observed throughout the coating layer as well. Samples were exposed to deuterium implantation followed by thermal desorption without exposure to air. Differences were observed in deuterium retention and postimplantation release behavior in the carbon-coated samples as compared with bare samples. For comparable implantation conditions (sample temperature of 400°C and an incident deuterium flux of approximately 6 × 1019 D/m2-s), the quantity of deuterium retained in the bare sample was less than that retained in the carbon-coated samples. Further, the release of the deuterium took place at lower temperatures for the bare beryllium surfaces than for carbon-coated beryllium samples.

  1. Ego Depletion Impairs Implicit Learning

    PubMed Central

    Thompson, Kelsey R.; Sanchez, Daniel J.; Wesley, Abigail H.; Reber, Paul J.

    2014-01-01

    Implicit skill learning occurs incidentally and without conscious awareness of what is learned. However, the rate and effectiveness of learning may still be affected by decreased availability of central processing resources. Dual-task experiments have generally found impairments in implicit learning, however, these studies have also shown that certain characteristics of the secondary task (e.g., timing) can complicate the interpretation of these results. To avoid this problem, the current experiments used a novel method to impose resource constraints prior to engaging in skill learning. Ego depletion theory states that humans possess a limited store of cognitive resources that, when depleted, results in deficits in self-regulation and cognitive control. In a first experiment, we used a standard ego depletion manipulation prior to performance of the Serial Interception Sequence Learning (SISL) task. Depleted participants exhibited poorer test performance than did non-depleted controls, indicating that reducing available executive resources may adversely affect implicit sequence learning, expression of sequence knowledge, or both. In a second experiment, depletion was administered either prior to or after training. Participants who reported higher levels of depletion before or after training again showed less sequence-specific knowledge on the post-training assessment. However, the results did not allow for clear separation of ego depletion effects on learning versus subsequent sequence-specific performance. These results indicate that performance on an implicitly learned sequence can be impaired by a reduction in executive resources, in spite of learning taking place outside of awareness and without conscious intent. PMID:25275517

  2. "When the going gets tough, who keeps going?" Depletion sensitivity moderates the ego-depletion effect.

    PubMed

    Salmon, Stefanie J; Adriaanse, Marieke A; De Vet, Emely; Fennis, Bob M; De Ridder, Denise T D

    2014-01-01

    Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In three studies, we assessed individual differences in depletion sensitivity, and demonstrate that depletion sensitivity moderates ego-depletion effects. The Depletion Sensitivity Scale (DSS) was employed to assess depletion sensitivity. Study 1 employs the DSS to demonstrate that individual differences in sensitivity to ego-depletion exist. Study 2 shows moderate correlations of depletion sensitivity with related self-control concepts, indicating that these scales measure conceptually distinct constructs. Study 3 demonstrates that depletion sensitivity moderates the ego-depletion effect. Specifically, participants who are sensitive to depletion performed worse on a second self-control task, indicating a stronger ego-depletion effect, compared to participants less sensitive to depletion.

  3. First measurements of deuterium-tritium and deuterium-deuterium fusion reaction yields in ignition-scalable direct-drive implosions

    SciTech Connect

    Forrest, C. J.; Radha, P. B.; Knauer, J. P.

    In this study, the deuterium-tritium (D-T) and deuterium-deuterium neutron yield ratio in cryogenic inertial confinement fusion (ICF) experiments is used to examine multifluid effects, traditionally not included in ICF modeling. This ratio has been measured for ignition-scalable direct-drive cryogenic DT implosions at the Omega Laser Facility using a high-dynamic-range neutron time-of-flight spectrometer. The experimentally inferred yield ratio is consistent with both the calculated values of the nuclear reaction rates and the measured preshot target-fuel composition. These observations indicate that the physical mechanisms that have been proposed to alter the fuel composition, such as species separation of the hydrogen isotopes, aremore » not significant during the period of peak neutron production in ignition-scalable cryogenic direct-drive DT implosions.« less

  4. First measurements of deuterium-tritium and deuterium-deuterium fusion reaction yields in ignition-scalable direct-drive implosions

    DOE PAGES

    Forrest, C. J.; Radha, P. B.; Knauer, J. P.; ...

    2017-03-03

    In this study, the deuterium-tritium (D-T) and deuterium-deuterium neutron yield ratio in cryogenic inertial confinement fusion (ICF) experiments is used to examine multifluid effects, traditionally not included in ICF modeling. This ratio has been measured for ignition-scalable direct-drive cryogenic DT implosions at the Omega Laser Facility using a high-dynamic-range neutron time-of-flight spectrometer. The experimentally inferred yield ratio is consistent with both the calculated values of the nuclear reaction rates and the measured preshot target-fuel composition. These observations indicate that the physical mechanisms that have been proposed to alter the fuel composition, such as species separation of the hydrogen isotopes, aremore » not significant during the period of peak neutron production in ignition-scalable cryogenic direct-drive DT implosions.« less

  5. Equations of state for hydrogen and deuterium.

    SciTech Connect

    Kerley, Gerald Irwin

    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 mixturemore » 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.« less

  6. Modeling Deuterium Release from Plasma Implanted Surfaces

    NASA Astrophysics Data System (ADS)

    Grossman, A. A.; Doerner, R.; Hirooka, Y.; Luckhardt, S. C.; Sze, F. C.

    1997-11-01

    When energetic ions or atoms of hydrogen isotopes interact with a solid surface, they may either be reflected or they may be implanted, a slowing down process within the subsurface layer of the energetic particles to thermal velocities. Subsequent interactions of the thermalized particles are those of diffusion and trapping within the material and the possibility of re-emission from the solid via desorption. The diffusion equation and its boundary conditions govern the transport of this thermalized hydrogen within the material. Diffusivities obey an Arrhenius law over as much as fourteen orders of magnitude for the temperature range of interest for a fusion reactor first wall and divertor plate. Using TMAP4, a variety of diffusion models are set up for comparison with experiments on PISCES which involve implantation and desorption of deuterium from beryllium, tungsten, carbon and boron carbide. The parameters and characteristics of the models which give the closest fit to the experimental data are reported. At the high fluences of these experiments, it is necessary to take into account saturation effects during implantation using a separate implantation layer with thickness given by TRIM and a higher trapping to lattice ratio than in the bulk in order to model the experimental data.

  7. Hydrogen isotope separation from water

    DOEpatents

    Jensen, R.J.

    1975-09-01

    A process for separating tritium from tritium-containing water or deuterium enrichment from water is described. The process involves selective, laser-induced two-photon excitation and photodissociation of those water molecules containing deuterium or tritium followed by immediate reaction of the photodissociation products with a scavenger gas which does not substantially absorb the laser light. The reaction products are then separated from the undissociated water. (auth)

  8. Depletion of the Complex Multiple Aquifer System of Jordan

    NASA Astrophysics Data System (ADS)

    Rödiger, T.; Siebert, C.; Geyer, S.; Merz, R.

    2017-12-01

    In many countries worldwide water scarcity pose a significant risk to the environment and the socio-economy. Particularly in countries where the available water resources are strongly limited by climatic conditions an accurate determination of the available water resources is of high priority, especially when water supply predominantly rely oon groundwater resources and their recharge. If groundwater abstraction exceeds the natural groundwater recharge in heavily used well field areas, overexploitation or persistent groundwater depletion occurs. This is the case in the Kingdom of Jordan, where a multi-layer aquifer complex forms the eastern subsurface catchment of the Dead Sea basin. Since the begin of the industrial and agricultural development of the country, dramatically falling groundwater levels, the disappearance of springs and saltwater intrusions from deeper aquifers is documented nation-wide. The total water budget is influenced by (i) a high climatic gradient from hyperarid to semiarid and (ii) the intnese anthropogenic abstraction. For this multi-layered aquifer system we developed a methodology to evaluate groundwater depletion by linking a hydrological and a numerical flow model including estimates of groundwater abstraction. Hence, we define groundwater depletion as the rate of groundwater abstraction in excess of natural recharge rate. Restricting our analysis, we calculated a range of groundwater depletion from 0% in the eastern Hamad basin to around 40% in the central part of Jordan and to extreme values of 100% of depletion in the Azraq and Disi basin.

  9. 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

  10. 25 CFR 179.202 - May the holder of a life estate without regard to waste deplete the resources?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... INTERIOR LAND AND WATER LIFE ESTATES AND FUTURE INTERESTS Life Estates Created Under AIPRA § 179.202 May... estate without regard to waste may cause lawful depletion or benefit from the lawful depletion of the...

  11. 25 CFR 179.202 - May the holder of a life estate without regard to waste deplete the resources?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... INTERIOR LAND AND WATER LIFE ESTATES AND FUTURE INTERESTS Life Estates Created Under AIPRA § 179.202 May... estate without regard to waste may cause lawful depletion or benefit from the lawful depletion of the...

  12. Highly Nuclear-Spin-Polarized Deuterium Atoms from the UV Photodissociation of Deuterium Iodide.

    PubMed

    Sofikitis, Dimitris; Glodic, Pavle; Koumarianou, Greta; Jiang, Hongyan; Bougas, Lykourgos; Samartzis, Peter C; Andreev, Alexander; Rakitzis, T Peter

    2017-06-09

    We report a novel highly spin-polarized deuterium (SPD) source, via the photodissociation of deuterium iodide at 270 nm. I(^{2}P_{3/2}) photofragments are ionized with m-state selectivity, and their velocity distribution measured via velocity-map slice imaging, from which the D polarization is determined. The process produces ∼100% electronically polarized D at the time of dissociation, which is then converted to ∼60% nuclear D polarization after ∼1.6  ns. These production times for SPD allow collision-limited densities of ∼10^{18}  cm^{-3} and at production rates of ∼10^{21}  s^{-1} which are 10^{6} and 10^{4} times higher than conventional (Stern-Gerlach separation) methods, respectively. We discuss the production of SPD beams, and combining high-density SPD with laser fusion, to investigate polarized D-T, D-^{3}He, and D-D fusion.

  13. Fully depleted back illuminated CCD

    DOEpatents

    Holland, Stephen Edward

    2001-01-01

    A backside illuminated charge coupled device (CCD) is formed of a relatively thick high resistivity photon sensitive silicon substrate, with frontside electronic circuitry, and an optically transparent backside ohmic contact for applying a backside voltage which is at least sufficient to substantially fully deplete the substrate. A greater bias voltage which overdepletes the substrate may also be applied. One way of applying the bias voltage to the substrate is by physically connecting the voltage source to the ohmic contact. An alternate way of applying the bias voltage to the substrate is to physically connect the voltage source to the frontside of the substrate, at a point outside the depletion region. Thus both frontside and backside contacts can be used for backside biasing to fully deplete the substrate. Also, high resistivity gaps around the CCD channels and electrically floating channel stop regions can be provided in the CCD array around the CCD channels. The CCD array forms an imaging sensor useful in astronomy.

  14. Thermodynamic and electrical properties of laser-shocked liquid deuterium

    NASA Astrophysics Data System (ADS)

    He, Zhiyu; Jia, Guo; Zhang, Fan; Luo, Kui; Huang, Xiuguang; Shu, Hua; Fang, Zhiheng; Ye, Junjian; Xie, Zhiyong; Xia, Miao; Fu, Sizu

    2018-01-01

    Liquid deuterium at high pressure and temperature has been observed to undergo significant electronic structural changes. Reflectivity and temperature measurements of liquid deuterium up to around 70 GPa were obtained using a quartz standard. The observed specific heat of liquid deuterium approaches the Dulong-Petit limit above 1 eV. Discussions on specific heat indicate a molecular dissociation below 1 eV and fully dissociated above 1.5 eV. Also, the electrical conductivity of deuterium estimated from reflectivity reaches 1.3 × 105 (Ωṡm)-1, proving that deuterium in this condition is a conducting degenerate liquid metal and undergo an insulator-metal transition. The results from specific heat, carrier density and conductivity agreed well with each other, which might be a reinforcement of the insulator-metal transition and the molecular dissociation. In addition, a new correction method of reflectivity in temperature calculation was proposed to improve the accuracy of temperature results. A new "dynamic calibration" was introduced in this work to make the experiments simpler and more accurate.

  15. The Effects of Deuterium Oxide on Certain Microorganisms

    SciTech Connect

    Giovanni, Rosalie

    1960-11-01

    The growth of several strains of E. coli and B. subtilis was inhibited by the presence of D 2O; the degree of inhibition exhibited by each strain was specific. The addition of 0.5 per cent NaCl to the D 2O media decreased the inhibition of growth. A deuterium-resistant mutant was obtained from one strain of E.coli. The incorporation of deuterium induces not only phenotypic but also genotypic changes in microorganisms. The effects induced by deuterium depend, however, on the genotype of the strain. The isotope appears to be mutagenic for some strains and some loci but not for others. Variousmore » types of forward mutations were obtained in some of the bacterial strains tested and the frequency of backward mutation was increased in two strains exposed to deuterium. Thymine containing deuterium, possibly in its methyl group, is not capable of inducing any detectable changes in a thymine requiring mutant. Cells, grown in D 2O media and subsequently washed and irradiated in H 2O saline, are more sensitive to ultraviolet irradiation than control cells.« less

  16. Distribution of deuterium and hydrogen in Zr and Ti foil assemblies under the action of a pulsed deuterium high-temperature plasma

    NASA Astrophysics Data System (ADS)

    Bondarenko, G. G.; Volobuev, I. V.; Eriskin, A. A.; Kobzev, A. P.; Nikulin, V. Ya.; Peregudova, E. N.; Silin, P. V.; Borovitskaya, I. V.

    2017-09-01

    Deuteron and proton elastic recoil detection analysis is used to study the accumulation and redistribution of deuterium and hydrogen in assemblies of two high-pure zirconium or titanium foils upon pulsed action of high-temperature deuterium plasma (PHTDP) in a plasma-focus installation PF-4. It is noted that, under the action of PHTDP, an implanted deuterium and hydrogen gas impurity are redistributed in the irradiated foils in large depths, which are significantly larger than the deuterium ion free paths (at their maximum velocity to 108 cm/s). The observed phenomenon is attributed to the carrying out of implanted deuterium and hydrogen under the action of powerful shock waves formed in the metallic foils under the action of PHTDP and/or the acceleration of diffusion of deuterium and hydrogen atoms under the action of a compression-rarefaction shock wave at the shock wave front with the redistribution of deuterium and hydrogen to large depths.

  17. Assessment of body fat in the pony: part II. Validation of the deuterium oxide dilution technique for the measurement of body fat.

    PubMed

    Dugdale, A H A; Curtis, G C; Milne, E; Harris, P A; Argo, C Mc

    2011-09-01

    Excessive accumulations or depletions of body fat have been associated with increased morbidity and mortality in horses and ponies. An objective, minimally-invasive method to accurately quantify body fat in living animals is required to aid nutritional management and define welfare/performance limits. To compare deuterium oxide (D(2) O) dilution-derived estimates of total body water (TBW) and body fat with values obtained by 'gold standard' proximate analysis and cadaver dissection. D(2) O dilution offers a valid method for the determination of TBW and body fat in equids. Seven mature (mean ± s.e. 13 ± 3 years, 212 ± 14 kg, body condition scores 1.25-7/9), healthy, Welsh Mountain pony mares, destined for euthanasia (for nonresearch purposes) were used. Blood samples were collected before and 4 h after D(2) O (0.11-0.13 g/kg bwt, 99.8 atom percent excess) administration. Plasma was analysed by gas isotope ratio mass spectrometry following filtration and zinc reduction. After euthanasia, white adipose tissue (WAT) mass was recorded before all body tissues were analysed by proximate chemical analyses. D(2) O-derived estimates of TBW and body fat were strongly associated with proximate analysis- and dissection-derived values (all r(2) >0.97, P≤0.0001). Bland-Altman analyses demonstrated good agreements between methods. D(2) O dilution slightly overestimated TBW (0.79%, limits of agreement (LoA) -3.75-2.17%) and underestimated total body lipid (1.78%, LoA -0.59-4.15%) and dissected WAT (0.72%, LoA -2.77-4.21%). This study provides the first validation of the D(2) O dilution method for the minimally-invasive, accurate, repeatable and objective measurement of body water and fat in living equids. © 2011 EVJ Ltd.

  18. Deuterium excess in precipitation of Alpine regions - moisture recycling.

    PubMed

    Froehlich, Klaus; Kralik, Martin; Papesch, Wolfgang; Rank, Dieter; Scheifinger, Helfried; Stichler, Willibald

    2008-03-01

    The paper evaluates long-term seasonal variations of the deuterium excess (d-excess = delta(2)H - 8. delta(18)O) in precipitation of stations located north and south of the main ridge of the Austrian Alps. It demonstrates that sub-cloud evaporation during precipitation and continental moisture recycling are local, respectively, regional processes controlling these variations. In general, sub-cloud evaporation decreases and moisture recycling increases the d-excess. Therefore, evaluation of d-excess variations in terms of moisture recycling, the main aim of this paper, includes determination of the effect of sub-cloud evaporation. Since sub-cloud evaporation is governed by saturation deficit and distance between cloud base and the ground, its effect on the d-excess is expected to be lower at mountain than at lowland/valley stations. To determine quantitatively this difference, we examined long-term seasonal d-excess variations measured at three selected mountain and adjoining valley stations. The altitude differences between mountain and valley stations ranged from 470 to 1665 m. Adapting the 'falling water drop' model by Stewart [J. Geophys. Res., 80(9), 1133-1146 (1975).], we estimated that the long-term average of sub-cloud evaporation at the selected mountain stations (altitudes between about 1600 and 2250 m.a.s.l.) is less than 1 % of the precipitation and causes a decrease of the d-excess of less than 2 per thousand. For the selected valley stations, the corresponding evaporated fraction is at maximum 7 % and the difference in d-excess ranges up to 8 per thousand. The estimated d-excess differences have been used to correct the measured long-term d-excess values at the selected stations. Finally, the corresponding fraction of water vapour has been estimated that recycled by evaporation of surface water including soil water from the ground. For the two mountain stations Patscherkofel and Feuerkogel, which are located north of the main ridge of the Alps, the

  19. 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.

  20. Polarized deuterium internal target at AmPS (NIKHEF)

    NASA Astrophysics Data System (ADS)

    Ferro-Luzzi, M.; Zhou, Z.-L.; van den Brand, J. F. J.; Bulten, H. J.; Alarcon, R.; van Bakel, N.; Botto, T.; Bouwhuis, M.; van Buuren, L.; Comfort, J.; Doets, M.; Dolfini, S.; Ent, R.; Geurts, D.; Heimberg, P.; Higinbotham, D. W.; de Jager, C. W.; Lang, J.; de Lange, D. J.; Norum, B.; Passchier, I.; Poolman, H. R.; Six, E.; Steijger, J.; Szczerba, D.; Unal, O.; de Vries, H.

    1998-01-01

    We describe the polarized deuterium target internal to the NIKHEF medium-energy electron storage ring. Tensor polarized deuterium was produced in an atomic beam source and injected into a storage cell target. A Breit-Rabi polarimeter was used to monitor the injected atomic beam intensity and polarization. An electrostatic ion-extraction system and a Wien filter were utilized to measure on-line the atomic fraction of the target gas in the storage cell. This device was supplemented with a tensor polarization analyzer using the neutron anisotropy of the 3H(d,n)α reaction at 60 keV. This method allows determining the density-averaged nuclear polarization of the target gas, independent of spatial and temporal variations. We address issues important for polarized hydrogen/deuterium internal targets, such as the effects of spin-exchange collisions and resonant transitions induced by the RF fields of the charged particle beam.

  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 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.

  3. DOPAMINE DEPLETION SLOWS RETINAL TRANSMISSION

    EPA Science Inventory

    In male hooded rats, depletion of norepinephrine and dopamine by a-methyl-paratyrosine (AMT) significantly increased the latencies of early peaks in flash-evoked potentials recorded from the visual cortex, lateral geniculate nucleus, and optic tract. These effects were not produc...

  4. Gas temperature measurements in deuterium hollow cathode glow discharge

    SciTech Connect

    Majstorović, Gordana, E-mail: gordana.majstorovic@va.mod.gov.rs; Šišović, Nikola, E-mail: nikolas@ff.bg.ac.rs

    2016-03-25

    We report results of optical emission spectroscopy measurements of rotational T{sub rot} and translational (gas) temperature of deuterium molecules in a hollow cathode (HC) glow discharge. The rotational temperature of excited electronic state of D{sub 2} was determined from the intensity distribution in the rotational structure of Q branch of the two Fulcher-α diagonal bands: (ν’=ν”=2) and (ν’=ν”=3). The population of excited energy levels, determined from relative line intensities, was used to derive radial rotational temperature distributions as well as gas temperature distribution of deuterium molecule.

  5. 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.

  6. Preparation of organic and water hydrogen for stable isotope analysis. Effects due to reaction vessels and zinc reagent

    SciTech Connect

    Schimmelmann, A.; DeNiro, M.J.

    1993-03-15

    Combustion of organic matter in sealed Pyrex, Vycor, and quartz ampules at temperatures between 520 and 900[degrees]C yields less than stoichiometric amounts of water. The loss of hydrogen to hydration reactions between water vapor and glass/quartz interferes with the determination of C/H and N/H elemental ratios in organic matter. The effect increases from quartz to Vycor to Pyrex, but the incomplete yield does not significantly affect the precision and accuracy of the determination of stable hydrogen isotope ratios. Reactions between water and Pyrex do not affect the conversion of water to hydrogen with zinc in Pyrex ampules at 500[degrees]C, whichmore » is quantitative, but even preoutgassed zinc contains a deuterium-depleted hydrogen blank. D/H ratios in hydrogen from the Zn method require a nonlinear correction to achieve compatibility with [delta]D values from the uranium method. 19 refs., 4 tabs.« less

  7. Baseline study of Oxygen 18 and deuterium in the Roswell, New Mexico, groundwater basin

    SciTech Connect

    Hoy, R.N.; Gross, G.W.

    The isotopic ratios of deuterium and oxygen 18 were measured in precipitation, surface, and ground water samples from the Roswell Artesian ground water basin in south-central New Mexico. The narrow range of D and 180 indicates mixing effects which are ascribed to one or more of the following factors: long ground water flow paths; large temperature fluctuations affecting which overwhelm the influence of elevation on precipitation; two sources of atmospheric moisture; interaquifer leakage; and recharge from intermittent streams with the flow-length expanding and contracting over large distances. It is concluded that a more precise definition of circulation patterns on themore » basis of stable isotope differences will require a much greater sampling frequency in both space and time.« less

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

    USDA-ARS?s Scientific Manuscript database

    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...

  9. Moisture transport across Canada: evidence from stable oxygen and deuterium isotope values of lakes and rivers

    NASA Astrophysics Data System (ADS)

    Oakley, J. R.; Patterson, W. P.

    2008-12-01

    Global warming models often contain a prediction of changes in precipitation, yet modern moisture cycling is poorly understood. Stable oxygen and deuterium isotope values of several thousand lake and river water samples collected from 2004 to 2008 throughout Canada and the Northern United States provide a means to evaluate variations in the movement of moisture across the northern North American continent. Our particular focus is on the moisture tracking in the province of Saskatchewan. The dominant moisture source for Saskatchewan is the Gulf of Mexico, though precipitation contains some water from the Pacific and Arctic Oceans as well. By sampling locations multiple times, we established time series of isotope variability that we can relate to meteorological variation. A series of cross-plots of oxygen to deuterium isotopes for each year exhibits an increase in slope from year to year that reflects an increase in humidity and/or precipitation throughout the Prairies from 2004 to 2008. We define the influence of temperature, precipitation and humidity on the change in slope for each suite of samples. Ultimately, by combining our evidence of moisture transport with a grid of long-term secular records from lakes, speleothems and tree-ring isotope variability, we can not only reconstruct changes in atmospheric circulation through time, but also better predict what will happen in the future under various global climate change scenarios.

  10. Electrolytic Installation in Order to Obtain Deuterium and to Fill the Pressure Deposits; INSTALACION ELECTROLITICA PARA LA OBTENCION DE DEUTERIO Y LLENADO DE DEPOSITOS A PRESION

    SciTech Connect

    Lopez, F.C.; Sanz, A.T.

    1959-01-01

    In order to obtain deuterium for the feed of accelerator ion sources, a sample and automatic electrolytic installation was constructed. The installation, used with a small compressor, can fill pressure vessels of 1 to 2 liter capacity with deuterium up to a pressure of 4 atmospheres in a few hours of operation. The electrolytic cell has a "V" shape and can operate with only 3 cc of heavy water. The electrodes are platinum and NaOH solution in the proportion of 15 wt.% is the electrolyte. The operation is automatic. The compressor is small, and the charge is low so thatmore » an auxiliary motor is not needed. The compressor piston is the only moving part. Deuterium losses are practically zero. (auth)« less

  11. First Measurements of Deuterium-Tritium and Deuterium-Deuterium Fusion Reaction Yields in Ignition-Scalable Direct-Drive Implosions.

    PubMed

    Forrest, C J; Radha, P B; Knauer, J P; Glebov, V Yu; Goncharov, V N; Regan, S P; Rosenberg, M J; Sangster, T C; Shmayda, W T; Stoeckl, C; Gatu Johnson, M

    2017-03-03

    The deuterium-tritium (D-T) and deuterium-deuterium neutron yield ratio in cryogenic inertial confinement fusion (ICF) experiments is used to examine multifluid effects, traditionally not included in ICF modeling. This ratio has been measured for ignition-scalable direct-drive cryogenic DT implosions at the Omega Laser Facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)OPCOB80030-401810.1016/S0030-4018(96)00325-2] using a high-dynamic-range neutron time-of-flight spectrometer. The experimentally inferred yield ratio is consistent with both the calculated values of the nuclear reaction rates and the measured preshot target-fuel composition. These observations indicate that the physical mechanisms that have been proposed to alter the fuel composition, such as species separation of the hydrogen isotopes [D. T. Casey et al., Phys. Rev. Lett. 108, 075002 (2012)PRLTAO0031-900710.1103/PhysRevLett.108.075002], are not significant during the period of peak neutron production in ignition-scalable cryogenic direct-drive DT implosions.

  12. First Measurements of Deuterium-Tritium and Deuterium-Deuterium Fusion Reaction Yields in Ignition-Scalable Direct-Drive Implosions

    NASA Astrophysics Data System (ADS)

    Forrest, C. J.; Radha, P. B.; Knauer, J. P.; Glebov, V. Yu.; Goncharov, V. N.; Regan, S. P.; Rosenberg, M. J.; Sangster, T. C.; Shmayda, W. T.; Stoeckl, C.; Gatu Johnson, M.

    2017-03-01

    The deuterium-tritium (D-T) and deuterium-deuterium neutron yield ratio in cryogenic inertial confinement fusion (ICF) experiments is used to examine multifluid effects, traditionally not included in ICF modeling. This ratio has been measured for ignition-scalable direct-drive cryogenic DT implosions at the Omega Laser Facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997), 10.1016/S0030-4018(96)00325-2] using a high-dynamic-range neutron time-of-flight spectrometer. The experimentally inferred yield ratio is consistent with both the calculated values of the nuclear reaction rates and the measured preshot target-fuel composition. These observations indicate that the physical mechanisms that have been proposed to alter the fuel composition, such as species separation of the hydrogen isotopes [D. T. Casey et al., Phys. Rev. Lett. 108, 075002 (2012), 10.1103/PhysRevLett.108.075002], are not significant during the period of peak neutron production in ignition-scalable cryogenic direct-drive DT implosions.

  13. 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…

  14. 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.

  15. Permeation of deuterium implanted into V-15Cr-5Ti

    NASA Astrophysics Data System (ADS)

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

    1987-02-01

    Permeation and reemission of deuterium for the vanadium alloy, V-15Cr-5Ti, was investigated using 3 keV, D 3+ ion beams from a small accelerator. The experiments consisted of measurement of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5 mm thick specimens heated to temperatures from 623 K to 823 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). For the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This is approximately 1000 times that seen in the austenitic stainless steel, PCA, and 200 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 that D = 1.4 × 10 -8 exp( -0.11 eV/ kT) (m 2/s), over the temperature range 723 K to 823 K.

  16. Biotechnological Patents Applications of the Deuterium Oxide in Human Health.

    PubMed

    da S Mariano, Reysla M; Bila, Wendell C; Trindade, Maria Jaciara F; Lamounier, Joel A; Galdino, Alexsandro S

    2017-01-01

    Deuterium oxide is a molecule that has been used for decades in several studies related to human health. Currently, studies on D2O have mobilized a "Race for Patenting" worldwide. Several patents have been registered from biomedical and technological studies of D2O showing the potential of this stable isotope in industry and health care ecosystems. Most of the patents related to the applications of the deuterium oxide in human health have been summarized in this review. The following patents databases were consulted: European Patent Office (Espacenet), the United States Patent and Trademark Office (USPTO), the United States Latin America Patents (LATIPAT), Patent scope -Search International and National Patent Collections (WIPO), Google Patents and Free Patents Online. With this review, the information was collected on recent publications including 22 patents related to deuterium oxide and its applications in different areas. This review showed that deuterium oxide is a promising component in different areas, including biotechnology, chemistry and medicine. In addition, the knowledge of this compound was covered, reinforcing its importance in the field of biotechnology and human health. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. Ozone Depletion from Nearby Supernovae

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the 'biologically active' UV flux received at the surface of the Earth, the supernova must occur at approximately or less than 8 parsecs.

  18. Properties of thick GEM in low-pressure deuterium

    NASA Astrophysics Data System (ADS)

    Lee, C. S.; Ota, S.; Tokieda, H.; Kojima, R.; Watanabe, Y. N.; Uesaka, T.

    2014-05-01

    Deuteron inelastic scattering (d, d') provides a promising spectroscopic tool to study nuclear incompressibility. In studies of deuteron inelastic scattering of unstable nuclei, measurements of low-energy recoiled particles is very important. In order to perform these measurements, we are developing a GEM-TPC based gaseous active target, called CAT (Center for nuclear study Active Target), operated with pure deuterium gas. The CAT has been tested with deuterium gas at 1 atm and 100-μm-thick GEMs. The low-pressure operation of CAT is planned in order to improve the detection capability for lower-energy recoil particles. A 400 μm-thick gas electron multiplier (THGEM) was chosen for the low-pressure operation of CAT. However, the properties of THGEM in low-pressure deuterium are currently undocumented. In this work, the performance of THGEM with low-pressure pure deuterium gas has been investigated. The effective gas gain of THGEM has been measured in various conditions using a 5.5-MeV 241Am alpha source. The effective gas gain was measured for 0.2-, 0.3- and 0.4-atm deuterium gas and a gas gain of about 103 was achieved by a double THGEM structure at 0.2 atm. The maximum achieved gain decreased with increasing gas pressure. The dependences of the effective gas gain on the electric field strengths of the drift, transfer and induction regions were investigated. The gain stability as a function of time in hydrogen gas was also tested and a relaxation time of THGEM of about 60 hours was observed with a continuous irradiation of alpha particles, which is significantly longer than previous studies have reported. We have tried to evaluate the gas gain of THGEM in deuterium gas by considering only the Townsend ionization process; however, it turned out that more phenomenological aspects, such as transfer efficiency, should be included in the evaluation. The basic properties of THGEM in low-pressure deuterium have been investigated for the first time.

  19. On the habitability of universes without stable deuterium

    NASA Astrophysics Data System (ADS)

    Adams, Fred C.; Grohs, Evan

    2017-05-01

    In both stars and in the early universe, the production of deuterium is the first step on the way to producing heavier nuclei. If the strong force were slightly weaker, then deuterium would not be stable, and many authors have noted that nuclesynthesis would be compromised so that helium production could not proceed through standard reaction chains. Motivated by the possibility that other regions of space-time could have different values for the fundamental constants, this paper considers stellar evolution in universes without stable deuterium and argues that such universes can remain habitable. Even in universes with no stellar nucleosynthesis, stars can form and will generate energy through gravitational contraction. Using both analytic estimates and a state-of-the-art stellar evolution code, we show that such stars can be sufficiently luminous and long-lived to support life. Stars with initial masses that exceed the Chandrasekhar mass cannot be supported by degeneracy pressure and will explode at the end of their contraction phase. The resulting explosive nucleosynthesis can thus provide the universe with some heavy elements. We also explore the possibility that helium can be produced in stellar cores through a triple-nucleon reaction that is roughly analogous to the triple-alpha reaction that operates in our universe. Stars burning hydrogen through this process are somewhat hotter than those in our universe, but otherwise play the same role. Next we show that with even trace amounts (metallicity Z ∼10-10) of heavy elements - produced through the triple-nucleon process or by explosive nucleosynthesis - the CNO cycle can operate and allow stars to function. Finally, we consider Big Bang Nucleosynthesis without stable deuterium and find that only trace amounts of helium are produced, with even smaller abundances of other nuclei. With stars evolving through gravitational contraction, explosive nucleosynthesis, the triple-nucleon reaction, and the CNO cycle

  20. Issues in Stratospheric Ozone Depletion.

    NASA Astrophysics Data System (ADS)

    Lloyd, Steven Andrew

    Following the announcement of the discovery of the Antarctic ozone hole in 1985 there have arisen a multitude of questions pertaining to the nature and consequences of polar ozone depletion. This thesis addresses several of these specific questions, using both computer models of chemical kinetics and the Earth's radiation field as well as laboratory kinetic experiments. A coupled chemical kinetic-radiative numerical model was developed to assist in the analysis of in situ field measurements of several radical and neutral species in the polar and mid-latitude lower stratosphere. Modeling was used in the analysis of enhanced polar ClO, mid-latitude diurnal variation of ClO, and simultaneous measurements of OH, HO_2, H_2 O and O_3. Most importantly, such modeling was instrumental in establishing the link between the observed ClO and BrO concentrations in the Antarctic polar vortex and the observed rate of ozone depletion. The principal medical concern of stratospheric ozone depletion is that ozone loss will lead to the enhancement of ground-level UV-B radiation. Global ozone climatology (40^circS to 50^ circN latitude) was incorporated into a radiation field model to calculate the biologically accumulated dosage (BAD) of UV-B radiation, integrated over days, months, and years. The slope of the annual BAD as a function of latitude was found to correspond to epidemiological data for non-melanoma skin cancers for 30^circ -50^circN. Various ozone loss scenarios were investigated. It was found that a small ozone loss in the tropics can provide as much additional biologically effective UV-B as a much larger ozone loss at higher latitudes. Also, for ozone depletions of > 5%, the BAD of UV-B increases exponentially with decreasing ozone levels. An important key player in determining whether polar ozone depletion can propagate into the populated mid-latitudes is chlorine nitrate, ClONO_2 . As yet this molecule is only indirectly accounted for in computer models and field

  1. Blistering behavior and deuterium retention in tungsten vanadium alloys exposed to deuterium plasma in the linear plasma device STEP

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Cheng, Long; Yuan, Yue; Qin, Shao-Yang; Arshad, Kameel; Guo, Wang-Guo; Wang, Zheng; Zhou, Zhang-Jian; Lu, Guang-Hong

    2018-03-01

    The behavior of tungsten-vanadium (W-V) alloys fabricated by powder metallurgy as a plasma facing material has been studied. W-V alloys with different vanadium concentrations (5 and 10 wt %) manufactured by hot pressing (HP) were exposed to deuterium plasma (flux ∼4.6 × 1021 m-2s-1, fluence ∼5.6 × 1025 m-2, ion energy ∼60 eV, target temperature ∼450 K) in the linear plasma device STEP at Beihang University. Three typical grains are observed on HP sintered W-V alloys and exhibit a significant effect on its performance under deuterium plasma irradiation. Surface blistering only occurs at W-enriched grains and is significantly mitigated in W-V alloys, especially in W-10 V, blistering is completely suppressed. On the other hand, deuterium retention dramatically increases in the W-V alloys due to vanadium addition. The deuterium retention in W-5 wt. % V is about 6.2 times more than that in rolled pure W, and this factor further increases to 6.9 when the V concentration rises to 10 wt %. We ascribe these phenomena to the changes of microstructures and components caused by vanadium addition.

  2. H2 Ortho-to-para Conversion on Grains: A Route to Fast Deuterium Fractionation in Dense Cloud Cores?

    NASA Astrophysics Data System (ADS)

    Bovino, S.; Grassi, T.; Schleicher, D. R. G.; Caselli, P.

    2017-11-01

    Deuterium fractionation, I.e., the enhancement of deuterated species with respect to non-deuterated ones, is considered to be a reliable chemical clock of star-forming regions. This process is strongly affected by the ortho-to-para H2 ratio. In this Letter we explore the effect of the ortho-para (o-p) H2 conversion on grains on the deuteration timescale in fully-depleted dense cores, including the most relevant uncertainties that affect this complex process. We show that (I) the o-p H2 conversion on grains is not strongly influenced by the uncertainties on the conversion time and the sticking coefficient, and (II) that the process is controlled by the temperature and the residence time of ortho-H2 on the surface, I.e., by the binding energy. We find that for binding energies between 330 and 550 K, depending on the temperature, the o-p H2 conversion on grains can shorten the deuterium fractionation timescale by orders of magnitude, opening a new route for explaining the large observed deuteration fraction D frac in dense molecular cloud cores. Our results suggest that the star formation timescale, when estimated through the timescale to reach the observed deuteration fractions, might be shorter than previously proposed. However, more accurate measurements of the binding energy are needed in order to better assess the overall role of this process.

  3. Exposure to nature counteracts aggression after depletion.

    PubMed

    Wang, Yan; She, Yihan; Colarelli, Stephen M; Fang, Yuan; Meng, Hui; Chen, Qiuju; Zhang, Xin; Zhu, Hongwei

    2018-01-01

    Acts of self-control are more likely to fail after previous exertion of self-control, known as the ego depletion effect. Research has shown that depleted participants behave more aggressively than non-depleted participants, especially after being provoked. Although exposure to nature (e.g., a walk in the park) has been predicted to replenish resources common to executive functioning and self-control, the extent to which exposure to nature may counteract the depletion effect on aggression has yet to be determined. The present study investigated the effects of exposure to nature on aggression following depletion. Aggression was measured by the intensity of noise blasts participants delivered to an ostensible opponent in a competition reaction-time task. As predicted, an interaction occurred between depletion and environmental manipulations for provoked aggression. Specifically, depleted participants behaved more aggressively in response to provocation than non-depleted participants in the urban condition. However, provoked aggression did not differ between depleted and non-depleted participants in the natural condition. Moreover, within the depletion condition, participants in the natural condition had lower levels of provoked aggression than participants in the urban condition. This study suggests that a brief period of nature exposure may restore self-control and help depleted people regain control over aggressive urges. © 2017 Wiley Periodicals, Inc.

  4. Physiological implications of anthropogenic environmental calcium depletion

    Treesearch

    Catherine H. Borer; Paul G. Schaberg; Donald H. DeHayes; Gary J. Hawley

    2001-01-01

    Recent evidence indicates that numerous anthropogenic factors can deplete calcium (Ca) from forested ecosystems. Although it is difficult to quantify the extent of this depletion, some reports indicate that the magnitude of Ca losses may be substantial. The potential for Ca depletion raises important questions about tree health. Only a fraction of foliar Ca is...

  5. Geochemical Investigation of Source Water to Cave Springs, Great Basin National Park, White Pine County, Nevada

    USGS Publications Warehouse

    Prudic, David E.; Glancy, Patrick A.

    2009-01-01

    Cave Springs supply the water for the Lehman Caves Visitor Center at Great Basin National Park, which is about 60 miles east of Ely, Nevada, in White Pine County. The source of water to the springs was investigated to evaluate the potential depletion caused by ground-water pumping in areas east of the park and to consider means to protect the supply from contamination. Cave Springs are a collection of several small springs that discharge from alluvial and glacial deposits near the contact between quartzite and granite. Four of the largest springs are diverted into a water-collection system for the park. Water from Cave Springs had more dissolved strontium, calcium, and bicarbonate, and a heavier value of carbon-13 than water from Marmot Spring at the contact between quartzite and granite near Baker Creek campground indicating that limestone had dissolved into water at Cave Springs prior to discharging. The source of the limestone at Cave Springs was determined to be rounded gravels from a pit near Baker, Nevada, which was placed around the springs during the reconstruction of the water-collection system in 1996. Isotopic compositions of water at Cave Springs and Marmot Spring indicate that the source of water to these springs primarily is from winter precipitation. Mixing of water at Cave Springs between alluvial and glacial deposits along Lehman Creek and water from quartzite is unlikely because deuterium and oxygen-18 values from a spring discharging from the alluvial and glacial deposits near upper Lehman Creek campground were heavier than the deuterium and oxygen-18 values from Cave Springs. Additionally, the estimated mean age of water determined from chlorofluorocarbon concentrations indicates water discharging from the spring near upper Lehman Creek campground is younger than that discharging from either Cave Springs or Marmot Spring. The source of water at Cave Springs is from quartzite and water discharges from the springs on the upstream side of the

  6. Structural transformations in austenitic stainless steel induced by deuterium implantation: irradiation at 100 K

    NASA Astrophysics Data System (ADS)

    Morozov, Oleksandr; Zhurba, Volodymyr; Neklyudov, Ivan; Mats, Oleksandr; Rud, Aleksandr; Chernyak, Nikolay; Progolaieva, Viktoria

    2015-03-01

    Deuterium thermal desorption spectra were investigated on the samples of austenitic stainless steel 18Cr10NiTi preimplanted at 100 K with deuterium ions in the dose range from 3 × 1015 to 5 × 1018 D/cm2. The kinetics of structural transformation development in the implantation steel layer was traced from deuterium thermodesorption spectra as a function of implanted deuterium concentration. At saturation of austenitic stainless steel 18Cr10NiTi with deuterium by means of ion implantation, structural-phase changes take place, depending on the dose of implanted deuterium. The maximum attainable concentration of deuterium in steel is C = 1 (at.D/at.met. = 1/1). The increase in the implanted dose of deuterium is accompanied by the increase in the retained deuterium content, and as soon as the deuterium concentration attains C ≈ 0.5 the process of shear martensitic structural transformation in steel takes place. It includes the formation of bands, body-centered cubic (bcc) crystal structure, and the ferromagnetic phase. Upon reaching the deuterium concentration C > 0.5, the presence of these molecules causes shear martensitic structural transformations in the steel, which include the formation of characteristic bands, bcc crystal structure, and the ferromagnetic phase. At C ≥ 0.5, two hydride phases are formed in the steel, the decay temperatures of which are 240 and 275 K. The hydride phases are formed in the bcc structure resulting from the martensitic structural transformation in steel.

  7. Direct depth distribution measurement of deuterium in bulk tungsten exposed to high-flux plasma

    NASA Astrophysics Data System (ADS)

    Taylor, C. N.; Shimada, M.

    2017-05-01

    Understanding tritium retention and permeation in plasma-facing components is critical for fusion safety and fuel cycle control. Glow discharge optical emission spectroscopy (GD-OES) is shown to be an effective tool to reveal the depth profile of deuterium in tungsten. Results confirm the detection of deuterium. A ˜46 μm depth profile revealed that the deuterium content decreased precipitously in the first 7 μm, and detectable amounts were observed to depths in excess of 20 μm. The large probing depth of GD-OES (up to 100s of μm) enables studies not previously accessible to the more conventional techniques for investigating deuterium retention. Of particular applicability is the use of GD-OES to measure the depth profile for experiments where high deuterium concentration in the bulk material is expected: deuterium retention in neutron irradiated materials, and ultra-high deuterium fluences in burning plasma environment.

  8. A method to estimate groundwater depletion from confining layers

    USGS Publications Warehouse

    Konikow, Leonard F.; Neuzil, Christopher E.

    2007-01-01

    Although depletion of storage in low‐permeability confining layers is the source of much of the groundwater produced from many confined aquifer systems, it is all too frequently overlooked or ignored. This makes effective management of groundwater resources difficult by masking how much water has been derived from storage and, in some cases, the total amount of water that has been extracted from an aquifer system. Analyzing confining layer storage is viewed as troublesome because of the additional computational burden and because the hydraulic properties of confining layers are poorly known. In this paper we propose a simplified method for computing estimates of confining layer depletion, as well as procedures for approximating confining layer hydraulic conductivity (K) and specific storage (Ss) using geologic information. The latter makes the technique useful in developing countries and other settings where minimal data are available or when scoping calculations are needed. As such, our approach may be helpful for estimating the global transfer of groundwater to surface water. A test of the method on a synthetic system suggests that the computational errors will generally be small. Larger errors will probably result from inaccuracy in confining layer property estimates, but these may be no greater than errors in more sophisticated analyses. The technique is demonstrated by application to two aquifer systems: the Dakota artesian aquifer system in South Dakota and the coastal plain aquifer system in Virginia. In both cases, depletion from confining layers was substantially larger than depletion from the aquifers.

  9. The Case of Ozone Depletion

    NASA Technical Reports Server (NTRS)

    Lambright, W. Henry

    2005-01-01

    While the National Aeronautics and Space Administration (NASA) is widely perceived as a space agency, since its inception NASA has had a mission dedicated to the home planet. Initially, this mission involved using space to better observe and predict weather and to enable worldwide communication. Meteorological and communication satellites showed the value of space for earthly endeavors in the 1960s. In 1972, NASA launched Landsat, and the era of earth-resource monitoring began. At the same time, in the late 1960s and early 1970s, the environmental movement swept throughout the United States and most industrialized countries. The first Earth Day event took place in 1970, and the government generally began to pay much more attention to issues of environmental quality. Mitigating pollution became an overriding objective for many agencies. NASA's existing mission to observe planet Earth was augmented in these years and directed more toward environmental quality. In the 1980s, NASA sought to plan and establish a new environmental effort that eventuated in the 1990s with the Earth Observing System (EOS). The Agency was able to make its initial mark via atmospheric monitoring, specifically ozone depletion. An important policy stimulus in many respects, ozone depletion spawned the Montreal Protocol of 1987 (the most significant international environmental treaty then in existence). It also was an issue critical to NASA's history that served as a bridge linking NASA's weather and land-resource satellites to NASA s concern for the global changes affecting the home planet. Significantly, as a global environmental problem, ozone depletion underscored the importance of NASA's ability to observe Earth from space. Moreover, the NASA management team's ability to apply large-scale research efforts and mobilize the talents of other agencies and the private sector illuminated its role as a lead agency capable of crossing organizational boundaries as well as the science-policy divide.

  10. Nickel-Catalyzed Proton-Deuterium Exchange (HDX) Procedures for Glycosidic Linkage Analysis of Complex Carbohydrates.

    PubMed

    Price, Neil P J; Hartman, Trina M; Vermillion, Karl E

    2015-07-21

    The structural analysis of complex carbohydrates typically requires the assignment of three parameters: monosaccharide composition, the position of glycosidic linkages between monosaccharides, and the position and nature of noncarbohydrate substituents. The glycosidic linkage positions are often determined by permethylation analysis, but this can be complicated by high viscosity or poor solubility, resulting in under-methylation. This is a drawback because an under-methylated position may be misinterpreted as the erroneous site of a linkage or substituent. Here, we describe an alternative approach to linkage analysis that makes use of a nonreversible deuterium exchange of C-H protons on the carbohydrate backbone. The exchange reaction is conducted in deuterated water catalyzed by Raney nickel, and results in the selective exchange of C-H protons adjacent to free hydroxyl groups. Hence, the position of the residual C-H protons is indicative of the position of glycosidic linkages or other substituents and can be readily assigned by heteronuclear single quantum coherence-nuclear magnetic resonance (HSQC-NMR) or, following suitable derivatization, by gas chromatography-mass spectroscopy (GC/MS) analysis. Moreover, because the only changes to the parent sugar are proton/deuterium exchanges, the composition and linkage analysis can be determined in a single step.

  11. A technique for determining the deuterium/hydrogen contrast map in neutron macromolecular crystallography.

    PubMed

    Chatake, Toshiyuki; Fujiwara, Satoru

    2016-01-01

    A difference in the neutron scattering length between hydrogen and deuterium leads to a high density contrast in neutron Fourier maps. In this study, a technique for determining the deuterium/hydrogen (D/H) contrast map in neutron macromolecular crystallography is developed and evaluated using ribonuclease A. The contrast map between the D2O-solvent and H2O-solvent crystals is calculated in real space, rather than in reciprocal space as performed in previous neutron D/H contrast crystallography. The present technique can thus utilize all of the amplitudes of the neutron structure factors for both D2O-solvent and H2O-solvent crystals. The neutron D/H contrast maps clearly demonstrate the powerful detectability of H/D exchange in proteins. In fact, alternative protonation states and alternative conformations of hydroxyl groups are observed at medium resolution (1.8 Å). Moreover, water molecules can be categorized into three types according to their tendency towards rotational disorder. These results directly indicate improvement in the neutron crystal structure analysis. This technique is suitable for incorporation into the standard structure-determination process used in neutron protein crystallography; consequently, more precise and efficient determination of the D-atom positions is possible using a combination of this D/H contrast technique and standard neutron structure-determination protocols.

  12. 76 FR 52994 - Application for a License To Export Heavy Water

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-24

    ... NUCLEAR REGULATORY COMMISSION Application for a License To Export Heavy Water Pursuant to 10 CFR... (liters). producing an active water). pharmaceutical ingredient known as CTP-499, which incorporates heavy water as the source of deuterium to achieve the hydrogen-deuterium exchange. November 30, 2010 December...

  13. Satellite-based estimates of groundwater depletion in India.

    PubMed

    Rodell, Matthew; Velicogna, Isabella; Famiglietti, James S

    2009-08-20

    Groundwater is a primary source of fresh water in many parts of the world. Some regions are becoming overly dependent on it, consuming groundwater faster than it is naturally replenished and causing water tables to decline unremittingly. Indirect evidence suggests that this is the case in northwest India, but there has been no regional assessment of the rate of groundwater depletion. Here we use terrestrial water storage-change observations from the NASA Gravity Recovery and Climate Experiment satellites and simulated soil-water variations from a data-integrating hydrological modelling system to show that groundwater is being depleted at a mean rate of 4.0 +/- 1.0 cm yr(-1) equivalent height of water (17.7 +/- 4.5 km(3) yr(-1)) over the Indian states of Rajasthan, Punjab and Haryana (including Delhi). During our study period of August 2002 to October 2008, groundwater depletion was equivalent to a net loss of 109 km(3) of water, which is double the capacity of India's largest surface-water reservoir. Annual rainfall was close to normal throughout the period and we demonstrate that the other terrestrial water storage components (soil moisture, surface waters, snow, glaciers and biomass) did not contribute significantly to the observed decline in total water levels. Although our observational record is brief, the available evidence suggests that unsustainable consumption of groundwater for irrigation and other anthropogenic uses is likely to be the cause. If measures are not taken soon to ensure sustainable groundwater usage, the consequences for the 114,000,000 residents of the region may include a reduction of agricultural output and shortages of potable water, leading to extensive socioeconomic stresses.

  14. Biomedical consequences of ozone depletion

    NASA Astrophysics Data System (ADS)

    Coohill, Thomas P.

    1994-07-01

    It is widely agreed that a portion of the earth's protective stratospheric ozone layer is being depleted. The major effect of this ozone loss will be an increase in the amount of ultraviolet radiation (UV reaching the biosphere. This increase will be completely contained within the UVB (290nm - 320nm). It is imperative that assessments be made of the effects of this additional UVB on living organisms. This requires a detailed knowledge of the UVB photobiology of these life forms. One analytical technique to aid in the approximations is the construction of UV action spectra for such important biological end-points as human skin cancer, cataracts, immune suppression; plant photosynthesis and crop yields; and aquatic organism responses to UVB, especially the phytoplankton. Combining these action spectra with the known solar spectrum (and estimates for various ozone depletion scenarios) can give rise to a series of effectiveness spectra for these parameters. This manuscript gives a first approximation, rough estimate, for the effectiveness spectra for some of these bioresponses, and a series of crude temporary values for how a 10% ozone loss would affect the above end-points. These are not intended to masquerade as final answers, but rather, to serve as beginning attempts for a process which should be continually refined. It is hoped that these estimates will be of some limited use to agencies, such as government and industry, that have to plan now for changes in human activities that might alter future atmospheric chemistry in a beneficial manner.

  15. Deuterium retention in tungsten in dependence of the surface conditions

    NASA Astrophysics Data System (ADS)

    Ogorodnikova, O. V.; Roth, J.; Mayer, M.

    2003-03-01

    The paper reviews hydrogen isotope retention and migration in tungsten (W). Due to a large scatter of the deuterium (D) retention database, new measurements of ion-driven D retention in polycrystalline W foil have been performed to clarify the mechanism of hydrogen isotope inventory in W. Deuterium retention has been investigated as a function of ion fluence, implantation temperature, incident energy and surface conditions. Special attention has been given on the investigation of D retention in thin films of tungsten carbide and tungsten oxide which can be formed on W surface in a fusion device. Such kinds of films increase the D retention in W. Several points are reviewed: (i) inventory in pure W, (ii) inventory in W pre-implanted by carbon ions and (iii) inventory in tungsten oxide.

  16. Inelastic X-ray Scattering from Shocked Liquid Deuterium

    DOE PAGES

    Regan, S. P.; Falk, K.; Gregori, G.; ...

    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. 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)×10 23 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.

  17. One Percent Determination of the Primordial Deuterium Abundance

    NASA Astrophysics Data System (ADS)

    Cooke, Ryan J.; Pettini, Max; Steidel, Charles C.

    2018-03-01

    We report a reanalysis of a near-pristine absorption system, located at a redshift {z}abs}=2.52564 toward the quasar Q1243+307, based on the combination of archival and new data obtained with the HIRES echelle spectrograph on the Keck telescope. This absorption system, which has an oxygen abundance [O/H] = ‑2.769 ± 0.028 (≃1/600 of the solar abundance), is among the lowest metallicity systems currently known where a precise measurement of the deuterium abundance is afforded. Our detailed analysis of this system concludes, on the basis of eight D I absorption lines, that the deuterium abundance of this gas cloud is {log}}10({{D}}/{{H}})=-4.622+/- 0.015, which is in very good agreement with the results previously reported by Kirkman et al., but with an improvement on the precision of this single measurement by a factor of ∼3.5. Combining this new estimate with our previous sample of six high precision and homogeneously analyzed D/H measurements, we deduce that the primordial deuterium abundance is {log}}10{({{D}}/{{H}})}{{P}}=-4.5974+/- 0.0052 or, expressed as a linear quantity, {10}5{({{D}}/{{H}})}{{P}}=2.527+/- 0.030; this value corresponds to a one percent determination of the primordial deuterium abundance. Combining our result with a big bang nucleosynthesis (BBN) calculation that uses the latest nuclear physics input, we find that the baryon density derived from BBN agrees to within 2σ of the latest results from the Planck cosmic microwave background data. Based on observations collected at the W.M. Keck Observatory which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  18. On-tissue Direct Monitoring of Global Hydrogen/Deuterium Exchange by MALDI Mass Spectrometry: Tissue Deuterium Exchange Mass Spectrometry (TDXMS)*

    PubMed Central

    Quanico, Jusal; Franck, Julien

    2016-01-01

    Hydrogen/deuterium exchange mass spectrometric (H/DXMS) methods for protein structural analysis are conventionally performed in solution. We present Tissue Deuterium Exchange Mass Spectrometry (TDXMS), a method to directly monitor deuterium uptake on tissue, as a means to better approximate the deuterium exchange behavior of proteins in their native microenvironment. Using this method, a difference in deuterium uptake behavior was observed when the same proteins were monitored in solution and on tissue. The higher maximum deuterium uptake at equilibrium for all proteins analyzed in solution suggests a more open conformation in the absence of interacting partners normally observed on tissue. We also demonstrate a difference in the deuterium uptake behavior of a few proteins across different morphological regions of the same tissue section. Modifications of the total number of hydrogens exchanged, as well as the kinetics of exchange, were both observed. These results provide information on the implication of protein interactions with partners as well as on the conformational changes related to these interactions, and illustrate the importance of examining protein deuterium exchange behavior in the presence of its specific microenvironment directly at the level of tissues. PMID:27512083

  19. Temperature dependence of deuterium retention mechanisms in tungsten

    NASA Astrophysics Data System (ADS)

    Roszell, J. P.; Davis, J. W.; Haasz, A. A.

    2012-10-01

    The retention of 500 eV D+ was measured as a function of implantation temperature in single- (SCW) and poly-crystalline (PCW) tungsten. The results show a decrease in retention of ˜2 orders of magnitude over the temperature range of 350-550 K in SCW and a decrease of an order of magnitude over the temperature range of 600-700 K in PCW. Inspection of the TDS spectra showed a shift in peak location from 600 to 800 K as temperature was increased above 350 K in SCW and above 450 K in PCW specimens. TMAP modeling showed that the change in peak location corresponds to a change in trapping energy from 1.3 eV for the 600 K peak to 2.1 eV for the 800 K peak. It is proposed that for implantations performed above 350 K in SCW and 450 K in PCW, deuterium-containing vacancies are able to diffuse and combine to create stable nano-bubbles within the crystal lattice. The formation of nano-bubbles due to the annihilation of deuterium-vacancy complexes results in a change in the trapping energy from 1.3 to 2.1 eV as well as a decrease in retention as some of the deuterium-vacancy complexes will be destroyed at surfaces or grain boundaries, decreasing the number of trapping sites available.

  20. Fast deuterium fractionation in magnetized and turbulent filaments

    NASA Astrophysics Data System (ADS)

    Körtgen, B.; Bovino, S.; Schleicher, D. R. G.; Stutz, A.; Banerjee, R.; Giannetti, A.; Leurini, S.

    2018-04-01

    Deuterium fractionation is considered as an important process to infer the chemical ages of prestellar cores in filaments. We present here the first magneto-hydrodynamical simulations including a chemical network to study deuterium fractionation in magnetized and turbulent filaments, with a line-mass of Mlin = 42 M⊙ pc-1 within a radius of R = 0.1 pc, and their substructures. The filaments typically show widespread deuterium fractionation with average values ≳ 0.01. For individual cores of similar age, we observe the deuteration fraction to increase with time, but also to be independent of their average properties such as density, virial or mass-to-magnetic flux ratio. We further find a correlation of the deuteration fraction with core mass, average H2 density and virial parameter only at late evolutionary stages of the filament and attribute this to the lifetime of the individual cores. Specifically, chemically old cores reveal higher deuteration fractions. Within the radial profiles of selected cores, we notice differences in the structure of the deuteration fraction or surface density, which we can attribute to their different turbulent properties. High deuteration fractions of the order 0.01 - 0.1 may be reached within approximately 200 kyrs, corresponding to two free-fall times, as defined for cylindrical systems, of the filaments.

  1. Fast deuterium fractionation in magnetized and turbulent filaments

    NASA Astrophysics Data System (ADS)

    Körtgen, B.; Bovino, S.; Schleicher, D. R. G.; Stutz, A.; Banerjee, R.; Giannetti, A.; Leurini, S.

    2018-07-01

    Deuterium fractionation is considered as an important process to infer the chemical ages of prestellar cores in filaments. We present here the first magnetohydrodynamical simulations including a chemical network to study deuterium fractionation in magnetized and turbulent filaments, with a line-mass of Mlin = 42 M⊙ pc-1 within a radius of R= 0.1 pc, and their sub-structures. The filaments typically show widespread deuterium fractionation with average values ≳0.01. For individual cores of similar age, we observe the deuteration fraction to increase with time, but also to be independent of their average properties such as density, virial, or mass-to-magnetic flux ratio. We further find a correlation of the deuteration fraction with core mass, average H2 density, and virial parameter only at late evolutionary stages of the filament and attribute this to the lifetime of the individual cores. Specifically, chemically old cores reveal higher deuteration fractions. Within the radial profiles of selected cores, we notice differences in the structure of the deuteration fraction or surface density, which we can attribute to their different turbulent properties. High deuteration fractions of the order of 0.01-0.1 may be reached within approximately 200 kyr, corresponding to two free-fall times, as defined for cylindrical systems, of the filaments.

  2. Polarized deuterium internal target at AmPS (NIKHEF)

    SciTech Connect

    Norum, Blaine; De Jager, Cornelis; Geurts, D.

    1997-08-01

    We describe the polarized deuterium target internal to the NIKHEF medium-energy electron storage ring. Tensor polarized deuterium was produced in an atomic beam source and injected into a storage cell target. A Breit-Rabi polarimeter was used to monitor the injected atomic beam intensity and polarization. An electrostatic ion-extraction system and a Wien filter were utilized to measure on-line the atomic fraction of the target gas in the storage cell. This device was supplemented with a tensor polarization analyzer using the neutron anisotropy of the 3H(d,n)sigma reaction at 60 keV. This method allows determining the density-averaged nuclear polarization of the targetmore » gas, independent of spatial and temporal variations. We address issues important for polarized hydrogen/deuterium internal targets, such as the effects of spin-exchange collisions and resonant transitions induced by the RF fields of the charged particle beam.« less

  3. Polarized deuterium internal target at AmPS (NIKHEF)

    SciTech Connect

    Ferro-Luzzi, M.; NIKHEF, P.O. Box 41882, 1009 DB Amsterdam; Zhou, Z.-L.

    1998-01-20

    We describe the polarized deuterium target internal to the NIKHEF medium-energy electron storage ring. Tensor polarized deuterium was produced in an atomic beam source and injected into a storage cell target. A Breit-Rabi polarimeter was used to monitor the injected atomic beam intensity and polarization. An electrostatic ion-extraction system and a Wien filter were utilized to measure on-line the atomic fraction of the target gas in the storage cell. This device was supplemented with a tensor polarization analyzer using the neutron anisotropy of the {sup 3}H(d,n){alpha} reaction at 60 keV. This method allows determining the density-averaged nuclear polarization of themore » target gas, independent of spatial and temporal variations. We address issues important for polarized hydrogen/deuterium internal targets, such as the effects of spin-exchange collisions and resonant transitions induced by the RF fields of the charged particle beam.« less

  4. Cryogenic distillation facility for isotopic purification of protium and deuterium

    SciTech Connect

    Alekseev, I.; Arkhipov, Ev.; Bondarenko, S.

    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 hydrogenmore » 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.« less

  5. Measurement of the deuterium Balmer series line emission on EAST

    SciTech Connect

    Wu, C. R.; Xu, Z.; Jin, Z.

    Volume recombination plays an important role towards plasma detachment for magnetically confined fusion devices. High quantum number states of the Balmer series of deuterium are used to study recombination. On EAST (Experimental Advanced Superconducting Tokamak), two visible spectroscopic measurements are applied for the upper/lower divertor with 13 channels, respectively. Both systems are coupled with Princeton Instruments ProEM EMCCD 1024B camera: one is equipped on an Acton SP2750 spectrometer, which has a high spectral resolution ∼0.0049 nm with 2400 gr/mm grating to measure the D{sub α}(H{sub α}) spectral line and with 1200 gr/mm grating to measure deuterium molecular Fulcher band emissionsmore » and another is equipped on IsoPlane SCT320 using 600 gr/mm to measure high-n Balmer series emission lines, allowing us to study volume recombination on EAST and to obtain the related line averaged plasma parameters (T{sub e}, n{sub e}) during EAST detached phases. This paper will present the details of the measurements and the characteristics of deuterium Balmer series line emissions during density ramp-up L-mode USN plasma on EAST.« less

  6. 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.

  7. Urea and deuterium mixtures at high pressures

    SciTech Connect

    Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate nomore » inclusion compound forms up to 3.7 GPa.« less

  8. 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

  9. 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

  10. Direct depth distribution measurement of deuterium in bulk tungsten exposed to high-flux plasma

    DOE PAGES

    Taylor, Chase N.; Shimada, M.

    2017-05-08

    Understanding tritium retention and permeation in plasma-facing components is critical for fusion safety and fuel cycle control. Glow discharge optical emission spectroscopy (GD-OES) is shown to be an effective tool to reveal the depth profile of deuterium in tungsten. Results confirm the detection of deuterium. Furthermore, a ~46 µm depth profile revealed that the deuterium content decreased precipitously in the first 7 µm, and detectable amounts were observed to depths in excess of 20 µm. The large probing depth of GD-OES (up to 100s of µm) enables studies not previously accessible to the more conventional techniques for investigating deuterium retention.more » Of particular applicability is the use of GD-OES to measure the depth profile for experiments where high diffusion is expected: deuterium retention in neutron irradiated materials, and ultra-high deuterium fluences in burning plasma environment.« less

  11. Deuterium gas-driven permeation and subsequent retention in rolled tungsten foils

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Zhou, Haishan; Li, Xiao-Chun; Xu, Yuping; An, Zhongqing; Mao, Hongmin; Xing, Wenjing; Hou, Qing; Luo, Guang-Nan

    2014-12-01

    Experiments concerning deuterium gas-driven permeation through rolled tungsten foils in the temperature range of 850-950 K and subsequent deuterium retention have been performed. The steady state permeation flux of deuterium is proportional to the square root of the driving pressure. The permeability of deuterium is in an order of 10-14 mol m-1 s-1 Pa-1/2 in this temperature range and the activation energy for permeation is 1.21 eV. Measurements of diffusivity are significantly affected by the driving pressure, which can be well explained by a saturable-trap model. Thermal desorption spectra of samples feature a single deuterium release peak at about 873 K. TMAP 4 modeling of this peak gives a detrapping energy of 1.70 eV, which fits the dissociation enthalpy of deuterium desorbing from the inner wall of vacancy clusters or pores in tungsten.

  12. Effects of chemical states of carbon on deuterium retention in carbon-containing materials

    NASA Astrophysics Data System (ADS)

    Oyaidzu, Makoto; Kimura, Hiromi; Nakahata, Toshihiko; Nishikawa, Yusuke; Tokitani, Masayuki; Oya, Yasuhisa; Iwakiri, Hirotomo; Yoshida, Naoaki; Okuno, Kenji

    2007-08-01

    Deuterium retention behavior in highly oriented pyrolytic graphite (HOPG), poly-crystalline diamond, poly-crystalline SiC, sintered WC, and converted B 4C were investigated to reveal tritium behavior in re-deposition and co-deposition layers. Such layers would contain carbon, when the first wall and/or divertor were made of graphite or carbon-containing materials. Furthermore, the employment of other materials such as tungsten, and first wall conditioning such as boronization would complicate the layers. No different deuterium trapping sites due to carbon from those in HOPG were found in all the samples, where two deuterium trapping processes were observed: hot atom chemical trapping of energetic deuterium by a dangling bond of carbon and thermochemical trapping of thermalized deuterium in a constituent atom vacancy surrounded by carbons. Additionally, the latter reaction could be easily counteracted by or competed with the other deuterium trapping reactions by constituent atoms.

  13. Ego depletion increases risk-taking.

    PubMed

    Fischer, Peter; Kastenmüller, Andreas; Asal, Kathrin

    2012-01-01

    We investigated how the availability of self-control resources affects risk-taking inclinations and behaviors. We proposed that risk-taking often occurs from suboptimal decision processes and heuristic information processing (e.g., when a smoker suppresses or neglects information about the health risks of smoking). Research revealed that depleted self-regulation resources are associated with reduced intellectual performance and reduced abilities to regulate spontaneous and automatic responses (e.g., control aggressive responses in the face of frustration). The present studies transferred these ideas to the area of risk-taking. We propose that risk-taking is increased when individuals find themselves in a state of reduced cognitive self-control resources (ego-depletion). Four studies supported these ideas. In Study 1, ego-depleted participants reported higher levels of sensation seeking than non-depleted participants. In Study 2, ego-depleted participants showed higher levels of risk-tolerance in critical road traffic situations than non-depleted participants. In Study 3, we ruled out two alternative explanations for these results: neither cognitive load nor feelings of anger mediated the effect of ego-depletion on risk-taking. Finally, Study 4 clarified the underlying psychological process: ego-depleted participants feel more cognitively exhausted than non-depleted participants and thus are more willing to take risks. Discussion focuses on the theoretical and practical implications of these findings.

  14. Aqueous Colloid + Polymer Depletion System for Confocal Microscopy and Rheology

    NASA Astrophysics Data System (ADS)

    Park, Nayoung; Umanzor, Esmeralda J.; Conrad, Jacinta C.

    2018-05-01

    We developed a model depletion system with colloidal particles that were refractive index- and density-matched to 80 (w/w)% glycerol in water, and characterized the effect of interparticle interactions on the structure and dynamics of non-equilibrium phases. 2,2,2-trifluoroethyl methacrylate-co-tert-butyl methacrylate copolymer particles were synthesized following Kodger et al. (Sci. Rep. 5, 14635 (2015)). Particles were dispersed in glycerol/water solutions to generate colloidal suspensions with good control over electrostatic interactions and a moderately high background viscosity of 55 mPa-s. To probe the effects of charge screening and depletion attractions on the suspension phase behavior, we added NaCl and polyacrylamide (M_w = 186 kDa) at various concentrations to particle suspensions formulated at volume fractions of phi = 0.05 and 0.3 and imaged the suspensions using confocal microscopy. The particles were nearly hard spheres at a NaCl concentration of 20 mM, but aggregated when the concentration of NaCl was further increased. Changes in the particle structure and dynamics with increasing concentration of the depletant polyacrylamide followed the trends expected from earlier experiments on depletion-driven gelation. Additionally, we measured the viscosity and corrected first normal stress difference of suspensions formulated at phi = 0.4 with and without added polymer. The solvent viscosity was suitable for rheology measurements without the onset of instabilities such as secondary flows or edge fracture. These results validate this system as an alternative to one common model system, suspensions of poly(methyl methacrylate) particles and polystyrene depletants in organic solvents, for investigating phase behavior and flow properties in attractive colloidal suspensions.

  15. Macroinvertebrate short-term responses to flow variation and oxygen depletion: A mesocosm approach.

    PubMed

    Calapez, Ana R; Branco, Paulo; Santos, José M; Ferreira, Teresa; Hein, Thomas; Brito, António G; Feio, Maria João

    2017-12-01

    In Mediterranean rivers, water scarcity is a key stressor with direct and indirect effects on other stressors, such as water quality decline and inherent oxygen depletion associated with pollutants inputs. Yet, predicting the responses of macroinvertebrates to these stressors combination is quite challenging due to the reduced available information, especially if biotic and abiotic seasonal variations are taken under consideration. This study focused on the response of macroinvertebrates by drift to single and combined effects of water scarcity and dissolved oxygen (DO) depletion over two seasons (winter and spring). A factorial design of two flow velocity levels - regular and low (vL) - with three levels of oxygen depletion - normoxia, medium depletion (dM) and higher depletion (dH) - was carried out in a 5-artificial channels system, in short-term experiments. Results showed that both stressors individually and together had a significant effect on macroinvertebrate drift ratio for both seasons. Single stressor effects showed that macroinvertebrate drift decreased with flow velocity reduction and increased with DO depletion, in both winter and spring experiments. Despite single stressors opposing effects in drift ratio, combined stressors interaction (vL×dM and vL×dH) induced a positive synergistic drift effect for both seasons, but only in winter the drift ratio was different between the levels of DO depletion. Stressors interaction in winter seemed to intensify drift response when reached lower oxygen saturation. Also, drift patterns were different between seasons for all treatments, which may depend on individual's life stage and seasonal behaviour. Water scarcity seems to exacerbate the oxygen depletion conditions resulting into a greater drifting of invertebrates. The potential effects of oxygen depletion should be evaluated when addressing the impacts of water scarcity on river ecosystems, since flow reductions will likely contribute to a higher oxygen

  16. SAIDE: A Semi-Automated Interface for Hydrogen/Deuterium Exchange Mass Spectrometry.

    PubMed

    Villar, Maria T; Miller, Danny E; Fenton, Aron W; Artigues, Antonio

    2010-01-01

    Deuterium/hydrogen exchange in combination with mass spectrometry (DH MS) is a sensitive technique for detection of changes in protein conformation and dynamics. Since temperature, pH and timing control are the key elements for reliable and efficient measurement of hydrogen/deuterium content in proteins and peptides, we have developed a small, semiautomatic interface for deuterium exchange that interfaces the HPLC pumps with a mass spectrometer. This interface is relatively inexpensive to build, and provides efficient temperature and timing control in all stages of enzyme digestion, HPLC separation and mass analysis of the resulting peptides. We have tested this system with a series of standard tryptic peptides reconstituted in a solvent containing increasing concentration of deuterium. Our results demonstrate the use of this interface results in minimal loss of deuterium due to back exchange during HPLC desalting and separation. For peptides reconstituted in a buffer containing 100% deuterium, and assuming that all amide linkages have exchanged hydrogen with deuterium, the maximum loss of deuterium content is only 17% of the label, indicating the loss of only one deuterium molecule per peptide.

  17. SAIDE: A Semi-Automated Interface for Hydrogen/Deuterium Exchange Mass Spectrometry

    PubMed Central

    Villar, Maria T.; Miller, Danny E.; Fenton, Aron W.; Artigues, Antonio

    2011-01-01

    Deuterium/hydrogen exchange in combination with mass spectrometry (DH MS) is a sensitive technique for detection of changes in protein conformation and dynamics. Since temperature, pH and timing control are the key elements for reliable and efficient measurement of hydrogen/deuterium content in proteins and peptides, we have developed a small, semiautomatic interface for deuterium exchange that interfaces the HPLC pumps with a mass spectrometer. This interface is relatively inexpensive to build, and provides efficient temperature and timing control in all stages of enzyme digestion, HPLC separation and mass analysis of the resulting peptides. We have tested this system with a series of standard tryptic peptides reconstituted in a solvent containing increasing concentration of deuterium. Our results demonstrate the use of this interface results in minimal loss of deuterium due to back exchange during HPLC desalting and separation. For peptides reconstituted in a buffer containing 100% deuterium, and assuming that all amide linkages have exchanged hydrogen with deuterium, the maximum loss of deuterium content is only 17% of the label, indicating the loss of only one deuterium molecule per peptide. PMID:25309638

  18. Depleted Uranium and Human Health.

    PubMed

    Faa, Armando; Gerosa, Clara; Fanni, Daniela; Floris, Giuseppe; Eyken, Peter V; Lachowicz, Joanna I; Nurchi, Valeria M

    2018-01-01

    Depleted uranium (DU) is generally considered an emerging pollutant, first extensively introduced into environment in the early nineties in Iraq, during the military operation called "Desert Storm". DU has been hypothesized to represent a hazardous element both for soldiers exposed as well as for the inhabitants of the polluted areas in the war zones. In this review, the possible consequences on human health of DU released in the environment are critically analyzed. In the first part, the chemical properties of DU and the principal civil and military uses are summarized. A concise analysis of the mechanisms underlying absorption, blood transport, tissue distribution and excretion of DU in the human body is the subject of the second part of this article. The following sections deal with pathological condition putatively associated with overexposure to DU. Developmental and birth defects, the Persian Gulf syndrome, and kidney diseases that have been associated to DU are the arguments treated in the third section. Finally, data regarding DU exposure and cancer insurgence will be critically analyzed, including leukemia/lymphoma, lung cancer, uterine cervix cancer, breast cancer, bladder cancer and testicular cancer. The aim of the authors is to give a contribution to the debate on DU and its effects on human health and disease. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  19. Electron scattering from high-momentum neutrons in deuterium

    NASA Astrophysics Data System (ADS)

    Klimenko, A. V.; Kuhn, S. E.; Butuceanu, C.; Egiyan, K. S.; Griffioen, K. A.; Adams, G.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Biselli, A. S.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Cazes, A.; Chen, S.; Cole, P. L.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Cummings, J. P.; Dashyan, N. B.; Devita, R.; Sanctis, E. De; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Dharmawardane, K. V.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Elouadrhiri, L.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Fersch, R. G.; Feuerbach, R. J.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gonenc, A.; Gordon, C. I. O.; Gothe, R. W.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Kellie, J. D.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Livingston, K.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Mueller, J.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Thoma, U.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Zana, L.; Zhang, J.; Zhao, B.

    2006-03-01

    We report results from an experiment measuring the semiinclusive reaction H2(e,e'ps) in which the proton ps 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 CEBAF large acceptance spectrometer. A reduced cross section was extracted for different values of final state missing mass W*, backward proton momentum p→s, and momentum transfer Q2. The data are compared to a simple plane wave impulse approximation (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. Within the framework of the simple spectator model, a “bound neutron structure function” F2neff was extracted as a function of W* and the scaling variable x* at extreme backward kinematics, where the effects of FSI appear to be smaller. For ps>0.4GeV/c, where the neutron is far off-shell, the model overestimates the value of F2neff in the region of x* between 0.25 and 0.6. A dependence of the bound neutron structure function on the neutron's “off-shell-ness” is one possible effect that can cause the observed deviation.

  20. Diagnosing radiative shocks from deuterium and tritium implosions on NIF.

    PubMed

    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.

  1. 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.

  2. Seasonality of Leaf Carbon Isotopic Composition and Leaf Water Isotopic Enrichment in a Mixed Evergreen Forest in Southern California

    NASA Astrophysics Data System (ADS)

    Santiago, L. S.; Sickman, J. O.; Goulden, M.; DeVan, C.; Pasquini, S. C.; Pivovaroff, A. L.

    2011-12-01

    Leaf carbon isotopic composition and leaf water isotopic enrichment reflect physiological processes and are important for linking local and regional scale processes to global patterns. We investigated how seasonality affects the isotopic composition of bulk leaf carbon, leaf sugar carbon, and leaf water hydrogen under a Mediterranean climate. Leaf and stem samples were collected monthly from four tree species (Calocedrus decurrens, Pinus lambertiana, Pinus ponderosa, and Quercus chrysolepis) at the James San Jacinto Mountain Reserve in southern California. Mean monthly bulk leaf carbon isotopic composition varied from -34.5 % in P. ponderosa to -24.7 % in P. lambertiana and became more depleted in 13C from the spring to the summer. Mean monthly leaf sugar varied from -29.3 % in P. ponderosa to -21.8 % in P. lambertiana and was enriched in 13C during the winter, spring and autumn, but depleted during the mid-summer. Leaf water hydrogen isotopic composition was 28.4 to 68.8 % more enriched in deuterium than source water and this enrichment was greater as seasonal drought progressed. These data indicate that leaf carbon and leaf water hydrogen isotopic composition provide sensitive measures that connect plant physiological processes to short-term climatic variability.

  3. Gadolinia depletion analysis by CASMO-4

    SciTech Connect

    Kobayashi, Y.; Saji, E.; Toba, A.

    1993-01-01

    CASMO-4 is the most recent version of the lattice physics code CASMO introduced by Studsvik. The principal aspects of the CASMO-4 model that differ from the models in previous CASMO versions are as follows: (1) heterogeneous model for two-dimensional transport theory calculations; and (2) microregion depletion model for burnable absorbers, such as gadolinia. Of these aspects, the first has previously been benchmarked against measured data of critical experiments and Monte Carlo calculations, verifying the high degree of accuracy. To proceed with CASMO-4 benchmarking, it is desirable to benchmark the microregion depletion model, which enables CASMO-4 to calculate gadolinium depletion directlymore » without the need for precalculated MICBURN cross-section data. This paper presents the benchmarking results for the microregion depletion model in CASMO-4 using the measured data of depleted gadolinium rods.« less

  4. Structural transformations in austenitic stainless steel induced by deuterium implantation: irradiation at 100 K.

    PubMed

    Morozov, Oleksandr; Zhurba, Volodymyr; Neklyudov, Ivan; Mats, Oleksandr; Rud, Aleksandr; Chernyak, Nikolay; Progolaieva, Viktoria

    2015-01-01

    Deuterium thermal desorption spectra were investigated on the samples of austenitic stainless steel 18Cr10NiTi preimplanted at 100 K with deuterium ions in the dose range from 3 × 10(15) to 5 × 10(18) D/cm(2). The kinetics of structural transformation development in the implantation steel layer was traced from deuterium thermodesorption spectra as a function of implanted deuterium concentration. At saturation of austenitic stainless steel 18Cr10NiTi with deuterium by means of ion implantation, structural-phase changes take place, depending on the dose of implanted deuterium. The maximum attainable concentration of deuterium in steel is C = 1 (at.D/at.met. = 1/1). The increase in the implanted dose of deuterium is accompanied by the increase in the retained deuterium content, and as soon as the deuterium concentration attains C ≈ 0.5 the process of shear martensitic structural transformation in steel takes place. It includes the formation of bands, body-centered cubic (bcc) crystal structure, and the ferromagnetic phase. Upon reaching the deuterium concentration C > 0.5, the presence of these molecules causes shear martensitic structural transformations in the steel, which include the formation of characteristic bands, bcc crystal structure, and the ferromagnetic phase. At C ≥ 0.5, two hydride phases are formed in the steel, the decay temperatures of which are 240 and 275 K. The hydride phases are formed in the bcc structure resulting from the martensitic structural transformation in steel.

  5. High homocysteine induces betaine depletion

    PubMed Central

    Imbard, Apolline; Benoist, Jean-François; Esse, Ruben; Gupta, Sapna; Lebon, Sophie; de Vriese, An S; de Baulny, Helene Ogier; Kruger, Warren; Schiff, Manuel; Blom, Henk J.

    2015-01-01

    Betaine is the substrate of the liver- and kidney-specific betaine-homocysteine (Hcy) methyltransferase (BHMT), an alternate pathway for Hcy remethylation. We hypothesized that BHMT is a major pathway for homocysteine removal in cases of hyperhomocysteinaemia (HHcy). Therefore, we measured betaine in plasma and tissues from patients and animal models of HHcy of genetic and acquired cause. Plasma was collected from patients presenting HHcy without any Hcy interfering treatment. Plasma and tissues were collected from rat models of HHcy induced by diet and from a mouse model of cystathionine β-synthase (CBS) deficiency. S-adenosyl-methionine (AdoMet), S-adenosyl-homocysteine (AdoHcy), methionine, betaine and dimethylglycine (DMG) were quantified by ESI—LC–MS/MS. mRNA expression was quantified using quantitative real-time (QRT)-PCR. For all patients with diverse causes of HHcy, plasma betaine concentrations were below the normal values of our laboratory. In the diet-induced HHcy rat model, betaine was decreased in all tissues analysed (liver, brain, heart). In the mouse CBS deficiency model, betaine was decreased in plasma, liver, heart and brain, but was conserved in kidney. Surprisingly, BHMT expression and activity was decreased in liver. However, in kidney, BHMT and SLC6A12 expression was increased in CBS-deficient mice. Chronic HHcy, irrespective of its cause, induces betaine depletion in plasma and tissues (liver, brain and heart), indicating a global decrease in the body betaine pool. In kidney, betaine concentrations were not affected, possibly due to overexpression of the betaine transporter SLC6A12 where betaine may be conserved because of its crucial role as an osmolyte. PMID:26182429

  6. High homocysteine induces betaine depletion.

    PubMed

    Imbard, Apolline; Benoist, Jean-François; Esse, Ruben; Gupta, Sapna; Lebon, Sophie; de Vriese, An S; de Baulny, Helene Ogier; Kruger, Warren; Schiff, Manuel; Blom, Henk J

    2015-04-28

    Betaine is the substrate of the liver- and kidney-specific betaine-homocysteine (Hcy) methyltransferase (BHMT), an alternate pathway for Hcy remethylation. We hypothesized that BHMT is a major pathway for homocysteine removal in cases of hyperhomocysteinaemia (HHcy). Therefore, we measured betaine in plasma and tissues from patients and animal models of HHcy of genetic and acquired cause. Plasma was collected from patients presenting HHcy without any Hcy interfering treatment. Plasma and tissues were collected from rat models of HHcy induced by diet and from a mouse model of cystathionine β-synthase (CBS) deficiency. S-adenosyl-methionine (AdoMet), S-adenosyl-homocysteine (AdoHcy), methionine, betaine and dimethylglycine (DMG) were quantified by ESI-LC-MS/MS. mRNA expression was quantified using quantitative real-time (QRT)-PCR. For all patients with diverse causes of HHcy, plasma betaine concentrations were below the normal values of our laboratory. In the diet-induced HHcy rat model, betaine was decreased in all tissues analysed (liver, brain, heart). In the mouse CBS deficiency model, betaine was decreased in plasma, liver, heart and brain, but was conserved in kidney. Surprisingly, BHMT expression and activity was decreased in liver. However, in kidney, BHMT and SLC6A12 expression was increased in CBS-deficient mice. Chronic HHcy, irrespective of its cause, induces betaine depletion in plasma and tissues (liver, brain and heart), indicating a global decrease in the body betaine pool. In kidney, betaine concentrations were not affected, possibly due to overexpression of the betaine transporter SLC6A12 where betaine may be conserved because of its crucial role as an osmolyte. © 2015 Author(s).

  7. Gulf war depleted uranium risks.

    PubMed

    Marshall, Albert C

    2008-01-01

    US and British forces used depleted uranium (DU) in armor-piercing rounds to disable enemy tanks during the Gulf and Balkan Wars. Uranium particulate is generated by DU shell impact and particulate entrained in air may be inhaled or ingested by troops and nearby civilian populations. As uranium is slightly radioactive and chemically toxic, a number of critics have asserted that DU exposure has resulted in a variety of adverse health effects for exposed veterans and nearby civilian populations. The study described in this paper used mathematical modeling to estimate health risks from exposure to DU during the 1991 Gulf War for both US troops and nearby Iraqi civilians. The analysis found that the risks of DU-induced leukemia or birth defects are far too small to result in an observable increase in these health effects among exposed veterans or Iraqi civilians. The analysis indicated that only a few ( approximately 5) US veterans in vehicles accidentally targeted by US tanks received significant exposure levels, resulting in about a 1.4% lifetime risk of DU radiation-induced fatal cancer (compared with about a 24% risk of a fatal cancer from all other causes). These veterans may have also experienced temporary kidney damage. Iraqi children playing for 500 h in DU-destroyed vehicles are predicted to incur a cancer risk of about 0.4%. In vitro and animal tests suggest the possibility of chemically induced health effects from DU internalization, such as immune system impairment. Further study is needed to determine the applicability of these findings for Gulf War exposure to DU. Veterans and civilians who did not occupy DU-contaminated vehicles are unlikely to have internalized quantities of DU significantly in excess of normal internalization of natural uranium from the environment.

  8. Residue depletion of tilmicosin in chicken tissues.

    PubMed

    Zhang, Yue; Jiang, Haiyang; Jin, Xingjun; Shen, Zhangqi; Shen, Jianzhong; Fu, Caixia; Guo, Junlin

    2004-05-05

    A high-performance liquid chromatography (HPLC) method with detection at 290 nm was modified and validated for the determination of tilmicosin residues in broiler chicken tissues. The limits of detection (LOD) of the method were 0.01 microg/g for muscle and 0.025 microg/g for liver and kidney. Average recoveries ranged from 80.4 to 88.3%. Relative standard deviation values ranged from 5.2 to 12.1%. Residue depletion of tilmicosin in broiler chickens was examined after dosing over a 5-day period by incorporation of the drug into drinking water at 37.5 and 75.0 mg/L. Tilmicosin concentrations in liver and kidney were highest on day 3 of medication and on day 5 in muscle, in both low- and high-dose groups. The residue levels in both groups were significantly higher in liver than in kidney or muscle. A minimum withdrawal time of 9 days was indicated for residue levels in muscle, liver, and kidney tissues below the maximum residue level (MRL).

  9. Viscoelasticity of Depletion-Induced Emulsion Gels

    NASA Astrophysics Data System (ADS)

    Meller, Amit; Stavans, Joel; Gisler, Thomas; Weitz, David A.

    1997-03-01

    The presence of non-adsorbing polymer in an oil-in-water emulsion results in a depletion attraction between the emulsion droplets, causing a phase separation into an droplet-rich phase and a polymer-rich phase largely devoid of emulsion droplets. At high enough droplet concentration, however, this phase separation is kinetically arrested to a gel-like state where large (diameter>50 μm) clusters of droplets are weakly connected via ramifications, leading to a measurable elastic modulus. We measure the mean-square displacement <Δ r ^2 (t)> of a droplet of size a inside a cluster using diffusing wave spectroscopy (DWS); by means of a generalized Stokes-Einstein relation we obtain frequency dependent storage and loss moduli G'(ω) and G''(ω), respectively. G'(ω) reaches a plateau at frequencies between 1 rad/s and 100 rad/s; this plateau modulus is found to scale with the hard-sphere energy density k_BT/a^3; within the clusters the droplets are densely packed, yet remain undeformed, the droplet volume fraction being determined by the osmotic pressure exerted by the polymer.

  10. Tylosin depletion in edible tissues of turkeys.

    PubMed

    Montesissa, C; De Liguoro, M; Santi, A; Capolongo, F; Biancotto, G

    1999-10-01

    The depletion of tylosin residues in edible turkey tissues was followed after 3 days of administration of tylosin tartrate at 500 mg l-1 in drinking water, to 30 turkeys. Immediately after the end of the treatment (day 0) and at day 1, 3, 5 and 10 of withdrawal, six turkeys (three males and three females) per time were sacrificed and samples of edible tissues were collected. Tissue homogenates were extracted, purified and analysed by HPLC according to a method previously published for the analysis of tylosin residues in pig tissues. In all tissues, tylosin residues were already below the detection limits of 50 micrograms kg-1 at time zero. However, in several samples of tissues (skin + fat, liver, kidney, muscle), from the six turkeys sacrificed at that time, one peak corresponding to an unknown tylosin equivalent was detected at measurable concentrations. The identification of this unknown compound was performed by LC-MS/MS analysis of the extracts from incurred samples. The mass fragmentation of the compound was consistent with the structure of tylosin D (the alcoholic derivative of tylosin A), the major metabolite of tylosin previously recovered and identified in tissues and/or excreta from treated chickens, cattle and pigs.

  11. Body composition prediction equations based on deuterium oxide dilution method in Mexican children: a national study.

    PubMed

    Ramírez, E; Valencia, M E; Bourges, H; Espinosa, T; Moya-Camarena, S Y; Salazar, G; Alemán-Mateo, H

    2012-10-01

    Obesity and undernutrition co-exist in many regions of Mexico. However, accurate assessments are difficult because epidemiological data on body composition are not available. The aim of this study was to facilitate assessments of body composition in Mexican school children of different geographical regions and ethnicity by developing equations for bioelectrical impedance and anthropometry based on deuterium oxide dilution. We evaluated 336 subjects (143 belonged to six major indigenous groups) from Northern, Central and Southern Mexico. We measured height (Ht), weight (Wt), tricipital skinfold (Tricp-SKF) and resistance (R) based on a bioimpedance analysis (BIA). Fat-free mass (FFM) and fat mass (FM) were estimated from measurements of total body water with the deuterium dilution technique. The final BIA equation was FFM (kg)=0.661 × Ht²/R+0.200 × Wt-0.320. The R² was 0.96; the square root of the mean square error (SRMSE) was 1.39 kg. The final anthropometric equation was FM (kg)=-1.067 × sex+0.458 × Tricp-SKF+0.263 × Wt-5.407. The R² was 0.91; SRMSE was 1.60 kg. The BIA equation had a bias of 0.095 kg and precision of 1.43 kg. The anthropometric equation had a bias of 0.047 kg and precision of 1.58 kg. We validated two equations for evaluating body composition in Mexican indigenous and non-indigenous children and youth from three main regions of the country. These equations provided reliable estimates and will promote a better understanding of both obesity and undernutrition.

  12. Deuterium and lithium-6 MAS NMR studies of manganese oxide electrode materials

    NASA Astrophysics Data System (ADS)

    Paik, Younkee

    Electrolytic manganese dioxide (EMD) is used world wide as the cathode materials in both lithium and alkaline primary (non-rechargeable) batteries. We have developed deuterium and lithium MAS NMR techniques to study EMD and related manganese oxides and hydroxides, where diffraction techniques are of limited value due to a highly defective nature of the structures. Deuterons in EMD, manganite, groutite, and deuterium-intercalated pyrolusite and ramsdellite were detected by NMR, for the first time, and their locations and motions in the structures were analyzed by applying variable temperature NMR techniques. Discharge mechanisms of EMD in alkaline (aqueous) electrolytes were studied, in conjunction with step potential electrochemical spectroscopic (SPECS) method, and five distinctive discharge processes were proposed. EMD is usually heat-treated at about 300--400°C to remove water to be used in lithium batteries. Details of the effects of heat-treatment, such as structural and compositional changes as a function of heat-treatment temperature, were studied by a combination of MAS NMR, XRD, and thermogravimetric analysis. Lithium local environments in heat-treated EMD (HEMD) that were discharged in lithium cells, were described in terms of related environments found in model compounds pyrolusite and ramsdellite where specific Li + sites were detected by MAS NMR and the hyperfine shift scale method of Grey et al. Acid-leaching of Li2MnO3 represents an approach for synthesizing new or modified manganese oxide electrode materials for lithium rechargeable batteries. Progressive removal of lithium from specific crystallographic sites, followed by a gradual change of the crystal structure, was monitored by a combination of NMR and XRD techniques.

  13. A neutron diagnostic for high current deuterium beams.

    PubMed

    Rebai, M; Cavenago, M; Croci, G; Dalla Palma, M; Gervasini, G; Ghezzi, F; Grosso, G; Murtas, F; Pasqualotto, R; Cippo, E Perelli; Tardocchi, M; Tollin, M; Gorini, G

    2012-02-01

    A neutron diagnostic for high current deuterium beams is proposed for installation on the spectral shear interferometry for direct electric field reconstruction (SPIDER, Source for Production of Ion of Deuterium Extracted from RF plasma) test beam facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission on the beam dump surface by placing a detector in close contact, right behind the dump. CNESM uses gas electron multiplier detectors equipped with a cathode that also serves as neutron-proton converter foil. The cathode is made of a thin polythene film and an aluminium film; it is designed for detection of neutrons of energy >2.2 MeV with an incidence angle < 45°. CNESM was designed on the basis of simulations of the different steps from the deuteron beam interaction with the beam dump to the neutron detection in the nGEM. Neutron scattering was simulated with the MCNPX code. CNESM on SPIDER is a first step towards the application of this diagnostic technique to the MITICA beam test facility, where it will be used to resolve the horizontal profile of the beam intensity.

  14. Unusually Large Deuterium Discrimination during Spore Photoproduct Formation

    PubMed Central

    2015-01-01

    The deuterium-labeling strategy has been widely used and proved highly effective in mechanistic investigation of chemical and biochemical reactions. However, it is often hampered by the incomplete label transfer, which subsequently obscures the mechanistic conclusion. During the study of photoinduced generation of 5-thyminyl-5,6-dihydrothymine, which is commonly called the spore photoproduct (SP), the Cadet laboratory found an incomplete (∼67%) deuterium transfer in SP formation, which contrasts to the exclusive transfer observed by the Li laboratory. Here, we investigated this discrepancy by re-examining the SP formation using d3-thymidine. We spiked the d3-thymidine with varying amounts of unlabeled thymidine before the SP photochemistry is performed. Strikingly, our data show that the reaction is highly sensitive to the trace protiated thymidine in the starting material. As many as 17-fold enrichment is detected in the formed SP, which may explain the previously observed one-third protium incorporation. Although commercially available deuterated reagents are generally satisfactory as mechanistic probes, our results argue that attention is still needed to the possible interference from the trace protiated impurity, especially when the reaction yield is low and large isotopic discrimination is involved. PMID:24820206

  15. A high deuterium abundance at redshift z = 0.7.

    PubMed

    Webb, J K; Carswell, R F; Lanzetta, K M; Ferlet, R; Lemoine, M; Vidal-Madjar, A; Bowen, D V

    1997-07-17

    Of the light elements, the primordial abundance of deuterium relative to hydrogen, (D/H)p, provides the most sensitive diagnostic for the cosmological mass density parameter, omegaB. Recent high-redshift D/H measurements are highly discrepant, although this may reflect observational uncertainties. The larger primordial D/H values imply a low omegaB (requiring the Universe to be dominated by non-baryonic matter), and cause problems for galactic chemical evolution models, which have difficulty in reproducing the steep decline in D/H to the present-day values. Conversely, the lower D/H values measured at high redshift imply an omegaB greater than that derived from 7Li and 4He abundance measurements, and may require a deuterium-abundance evolution that is too low to easily explain. Here we report the first measurement of D/H at intermediate redshift (z = 0.7010), in a gas cloud selected to minimize observational uncertainties. Our analysis yields a value of D/H ((2.0 +/- 0.5) x 10[-4]) which is at the upper end of the range of values measured at high redshifts. This finding, together with other independent observations, suggests that there may be inhomogeneity in (D/H)p of at least a factor of ten.

  16. Rayleigh-Taylor instability experiments in cryogenic deuterium

    NASA Astrophysics Data System (ADS)

    Hansen, J. F.; Smalyuk, V. A.

    2005-10-01

    We report on experiments under way at the Omega laser, using cryogenic deuterium to study Rayleigh-Taylor instabilities in laser targets. These instabilities are important in astrophysical situations (e.g., mixing of the different shells during a supernova explosion) and in inertial fusion (during the compression stage of a fusion target). They can be studied in small (˜1 mm) shock tubes filled with one heavy and one light material, with an interface between the two materials that is machined to seed the instability. A high-energy laser (˜5 kJ) drives a shock from the heavy to the light material. The evolution of the interface is studied using gated x-ray cameras, where x-ray illumination is obtained from additional laser beams focused on metal backlighter foils. Traditionally the heavy material is CH (1 g/cm^3) doped with I or Br for improved contrast, while the light material is a low-density (˜0.1 g/cm^3) C foam. The goal of the current experiments is to determine if contrast can be improved even further by replacing the foam with cryogenic deuterium, which has a density similar to the foam, but a lower x-ray opacity allowing clearer images, including images taken at late times in the evolution. Work performed under the auspices of the Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48.

  17. Hydrogen and deuterium in the local interstellar medium

    SciTech Connect

    Murthy, J.N.

    1987-01-01

    This work reports on the results of a series of IUE observations of interstellar HI and DI Ly..cap alpha.. absorption against the chromospheric Ly..cap alpha.. emission of the nearby late-type stars ..cap alpha.. Cen B(1.3 pc), epsilon Eri (3.3 pc), Procyon (3.5 pc), Altair (5.1 pc), Capella (13.2 pc), and HR 1099 (33 pc). The density, velocity dispersion, and bulk velocity of the neutral hydrogen along the line of sight to each of these stars was derived. Lower limits were placed on the deuterium-to-hydrogen (D/H) ratio towards the same stars. These IUE results are generally consistent with previous observations ofmore » the same stars with the Copernicus satellite showing that this modeling procedure is independent of stellar variations over a period of several years. The HI absorption profile towards Altair shows a broad saturated core and steep line wings, consistent with a multicomponent interstellar medium in that direction. The bulk velocities towards the other stars are consistent with a bulk flow from the approximate direction of the galactic center but do show local variations from a uniform flow, possibly indicating a complicated velocity structure even in the solar neighborhood. Interstellar deuterium is detected towards every star except Altair and the derived values for the D/H ratio are consistent with those previously found with Copernicus.« less

  18. Deuterium in the local interstellar medium towards hot stars

    NASA Astrophysics Data System (ADS)

    Vidal-Madjar, Alfred

    1996-07-01

    The proposed observations are the necessary continuation of previous approved proposals aiming at deriving the deuterium abundance in the local interstellar medium toward nearby hot stars. This estimate is of prime importance for the determination of the present D abundance within the Galaxy, one of the key-parameter of galactic evolution models. From Cycle 1 observations, we proved the efficiency of using nearby hot stars as targets. The data, in particular in the direction of G191-B2B {Lemoine et al., 1995}, also have demonstrated the extreme importance of observing, beside the HI and DI lines, the spectral region around the NI triplet. Very new observations just obtained {ID 5893} with GHRS ECH-A at the highest resolution constrain more tightly the evaluated D/H ratio. A significant variation {factor 3} of the D/H ratio from one component to the other is strongly infered toward G191-B2B. Although being a long lasting question, such a variability - if true - needs to be confirmed and understood to be able to estimate the really representative present day deuterium abundance, which may very well be different from the precise measurement in the direction of Capella {Linsky et al., 1993}. This motivates the present proposal aimed to derive D/H toward another white dwarf and its companion star for which the velocity structure is already rather well known: Sirius A and B.

  19. A neutron diagnostic for high current deuterium beams

    SciTech Connect

    Rebai, M.; Perelli Cippo, E.; Cavenago, M.

    2012-02-15

    A neutron diagnostic for high current deuterium beams is proposed for installation on the spectral shear interferometry for direct electric field reconstruction (SPIDER, Source for Production of Ion of Deuterium Extracted from RF plasma) test beam facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission on the beam dump surface by placing a detector in close contact, right behind the dump. CNESM uses gas electron multiplier detectors equipped with a cathode that also serves as neutron-proton converter foil. The cathode is made of a thinmore » polythene film and an aluminium film; it is designed for detection of neutrons of energy >2.2 MeV with an incidence angle < 45 deg. CNESM was designed on the basis of simulations of the different steps from the deuteron beam interaction with the beam dump to the neutron detection in the nGEM. Neutron scattering was simulated with the MCNPX code. CNESM on SPIDER is a first step towards the application of this diagnostic technique to the MITICA beam test facility, where it will be used to resolve the horizontal profile of the beam intensity.« less

  20. Regio-Selective Intramolecular Hydrogen/Deuterium Exchange in Gas-Phase Electron Transfer Dissociation.

    PubMed

    Hamuro, Yoshitomo

    2017-05-01

    Protein backbone amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) typically utilizes enzymatic digestion after the exchange reaction and before MS analysis to improve data resolution. Gas-phase fragmentation of a peptic fragment prior to MS analysis is a promising technique to further increase the resolution. The biggest technical challenge for this method is elimination of intramolecular hydrogen/deuterium exchange (scrambling) in the gas phase. The scrambling obscures the location of deuterium. Jørgensen's group pioneered a method to minimize the scrambling in gas-phase electron capture/transfer dissociation. Despite active investigation, the mechanism of hydrogen scrambling is not well-understood. The difficulty stems from the fact that the degree of hydrogen scrambling depends on instruments, various parameters of mass analysis, and peptide analyzed. In most hydrogen scrambling investigations, the hydrogen scrambling is measured by the percentage of scrambling in a whole molecule. This paper demonstrates that the degree of intramolecular hydrogen/deuterium exchange depends on the nature of exchangeable hydrogen sites. The deuterium on Tyr amide of neurotensin (9-13), Arg-Pro-Tyr-Ile-Leu, migrated significantly faster than that on Ile or Leu amides, indicating the loss of deuterium from the original sites is not mere randomization of hydrogen and deuterium but more site-specific phenomena. This more precise approach may help understand the mechanism of intramolecular hydrogen exchange and provide higher confidence for the parameter optimization to eliminate intramolecular hydrogen/deuterium exchange during gas-phase fragmentation. Graphical Abstract ᅟ.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  2. Regio-Selective Intramolecular Hydrogen/Deuterium Exchange in Gas-Phase Electron Transfer Dissociation

    NASA Astrophysics Data System (ADS)

    Hamuro, Yoshitomo

    2017-05-01

    Protein backbone amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) typically utilizes enzymatic digestion after the exchange reaction and before MS analysis to improve data resolution. Gas-phase fragmentation of a peptic fragment prior to MS analysis is a promising technique to further increase the resolution. The biggest technical challenge for this method is elimination of intramolecular hydrogen/deuterium exchange (scrambling) in the gas phase. The scrambling obscures the location of deuterium. Jørgensen's group pioneered a method to minimize the scrambling in gas-phase electron capture/transfer dissociation. Despite active investigation, the mechanism of hydrogen scrambling is not well-understood. The difficulty stems from the fact that the degree of hydrogen scrambling depends on instruments, various parameters of mass analysis, and peptide analyzed. In most hydrogen scrambling investigations, the hydrogen scrambling is measured by the percentage of scrambling in a whole molecule. This paper demonstrates that the degree of intramolecular hydrogen/deuterium exchange depends on the nature of exchangeable hydrogen sites. The deuterium on Tyr amide of neurotensin (9-13), Arg-Pro-Tyr-Ile-Leu, migrated significantly faster than that on Ile or Leu amides, indicating the loss of deuterium from the original sites is not mere randomization of hydrogen and deuterium but more site-specific phenomena. This more precise approach may help understand the mechanism of intramolecular hydrogen exchange and provide higher confidence for the parameter optimization to eliminate intramolecular hydrogen/deuterium exchange during gas-phase fragmentation.

  3. Kinetic and Mechanistic Studies of the Deuterium Exchange in Classical Keto-Enol Tautomeric Equilibrium Reactions

    ERIC Educational Resources Information Center

    Nichols, Michael A.; Waner, Mark J.

    2010-01-01

    An extension of the classic keto-enol tautomerization of beta-dicarbonyl compounds into a kinetic analysis of deuterium exchange is presented. It is shown that acetylacetone and ethyl acetoacetate undergo nearly complete deuterium exchange of the alpha-methylene carbon when dissolved in methanol-d[subscript 4]. The extent of deuteration may be…

  4. Measurement of deuterium-labeled phylloquinone in plasma by LC-APCI-MS

    USDA-ARS?s Scientific Manuscript database

    Deuterium-labeled vegetables were fed to humans for the measurement of both unlabeled and deuterium-labeled phylloquinone in plasma. We developed a technique to determine the quantities of these compounds using liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization (LC...

  5. Development of positron annihilation spectroscopy for investigating deuterium decorated voids in neutron-irradiated tungsten

    NASA Astrophysics Data System (ADS)

    Taylor, C. N.; Shimada, M.; Merrill, B. J.; Akers, D. W.; Hatano, Y.

    2015-08-01

    The present work is a continuation of a recent research to develop and optimize positron annihilation spectroscopy (PAS) for characterizing neutron-irradiated tungsten. Tungsten samples were exposed to neutrons in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory and damaged to 0.025 and 0.3 dpa. Subsequently, they were exposed to deuterium plasmas in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory. The implanted deuterium was desorbed through sample heating to 900 °C, and Doppler broadening (DB)-PAS was performed both before and after heating. Results show that deuterium impregnated tungsten is identified as having a smaller S-parameter. The S-parameter increases after deuterium desorption. Microstructural changes also occur during sample heating. These effects can be isolated from deuterium desorption by comparing the S-parameters from the deuterium-free back face with the deuterium-implanted front face. The application of using DB-PAS to examine deuterium retention in tungsten is examined.

  6. Mass separation of deuterium and helium with conventional quadrupole mass spectrometer by using varied ionization energy

    SciTech Connect

    Yu, Yaowei; Hu, Jiansheng, E-mail: hujs@ipp.ac.cn; Wan, Zhao

    2016-03-15

    Deuterium pressure in deuterium-helium mixture gas is successfully measured by a common quadrupole mass spectrometer (model: RGA200) with a resolution of ∼0.5 atomic mass unit (AMU), by using varied ionization energy together with new developed software and dedicated calibration for RGA200. The new software is developed by using MATLAB with the new functions: electron energy (EE) scanning, deuterium partial pressure measurement, and automatic data saving. RGA200 with new software is calibrated in pure deuterium and pure helium 1.0 × 10{sup −6}–5.0 × 10{sup −2} Pa, and the relation between pressure and ion current of AMU4 under EE = 25 eVmore » and EE = 70 eV is obtained. From the calibration result and RGA200 scanning with varied ionization energy in deuterium and helium mixture gas, both deuterium partial pressures (P{sub D{sub 2}}) and helium partial pressure (P{sub He}) could be obtained. The result shows that deuterium partial pressure could be measured if P{sub D{sub 2}} > 10{sup −6} Pa (limited by ultimate pressure of calibration vessel), and helium pressure could be measured only if P{sub He}/P{sub D{sub 2}} > 0.45, and the measurement error is evaluated as 15%. This method is successfully employed in EAST 2015 summer campaign to monitor deuterium outgassing/desorption during helium discharge cleaning.« less

  7. Regional strategies for the accelerating global problem of groundwater depletion

    NASA Astrophysics Data System (ADS)

    Aeschbach-Hertig, Werner; Gleeson, Tom

    2012-12-01

    Groundwater--the world's largest freshwater resource--is critically important for irrigated agriculture and hence for global food security. Yet depletion is widespread in large groundwater systems in both semi-arid and humid regions of the world. Excessive extraction for irrigation where groundwater is slowly renewed is the main cause of the depletion, and climate change has the potential to exacerbate the problem in some regions. Globally aggregated groundwater depletion contributes to sea-level rise, and has accelerated markedly since the mid-twentieth century. But its impacts on water resources are more obvious at the regional scale, for example in agriculturally important parts of India, China and the United States. Food production in such regions can only be made sustainable in the long term if groundwater levels are stabilized. To this end, a transformation is required in how we value, manage and characterize groundwater systems. Technical approaches--such as water diversion, artificial groundwater recharge and efficient irrigation--have failed to balance regional groundwater budgets. They need to be complemented by more comprehensive strategies that are adapted to the specific social, economic, political and environmental settings of each region.

  8. Possible ozone depletions following nuclear explosions

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Borucki, W. J.; Turco, R. P.

    1975-01-01

    The degree of depletion of the ozone layer ensuing after delivery of strategic nuclear warheads (5000 and 10,000 Mton) due to production of nitrogen oxides is theoretically assessed. Strong depletions are calculated for 16-km and 26-km altitudes, peaking 1-2 months after detonation and lasting for three years, while a significant depletion at 36 km would peak after one year. Assuming the explosions occur between 30 and 70 deg N, these effects should be much more pronounced in this region than over the Northern Hemisphere as a whole. It is concluded that Hampson's concern on this matter (1974) is well-founded.-

  9. Disassembly time of deuterium-cluster-fusion plasma irradiated by an intense laser pulse.

    PubMed

    Bang, W

    2015-07-01

    Energetic deuterium ions from large deuterium clusters (>10nm diameter) irradiated by an intense laser pulse (>10(16)W/cm(2)) produce DD fusion neutrons for a time interval determined by the geometry of the resulting fusion plasma. We present an analytical solution of this time interval, the plasma disassembly time, for deuterium plasmas that are cylindrical in shape. Assuming a symmetrically expanding deuterium plasma, we calculate the expected fusion neutron yield and compare with an independent calculation of the yield using the concept of a finite confinement time at a fixed plasma density. The calculated neutron yields agree quantitatively with the available experimental data. Our one-dimensional simulations indicate that one could expect a tenfold increase in total neutron yield by magnetically confining a 10-keV deuterium fusion plasma for 10ns.

  10. Disassembly time of deuterium-cluster-fusion plasma irradiated by an intense laser pulse

    SciTech Connect

    Bang, W.

    Energetic deuterium ions from large deuterium clusters (>10 nm diameter) irradiated by an intense laser pulse (>10¹⁶ W/cm²) produce DD fusion neutrons for a time interval determined by the geometry of the resulting fusion plasma. We show an analytical solution of this time interval, the plasma disassembly time, for deuterium plasmas that are cylindrical in shape. Assuming a symmetrically expanding deuterium plasma, we calculate the expected fusion neutron yield and compare with an independent calculation of the yield using the concept of a finite confinement time at a fixed plasma density. The calculated neutron yields agree quantitatively with the availablemore » experimental data. Our one-dimensional simulations indicate that one could expect a tenfold increase in total neutron yield by magnetically confining a 10 - keV deuterium fusion plasma for 10 ns.« less

  11. The temperature and ion energy dependence of deuterium retention in lithium films

    NASA Astrophysics Data System (ADS)

    Buzi, Luxherta; Koel, Bruce E.; Skinner, Charles H.

    2016-10-01

    Lithium conditioning of plasma facing components in magnetic fusion devices has improved plasma performance and lowered hydrogen recycling. For applications of lithium in future high heat flux and long pulse duration machines it is important to understand and parameterize deuterium retention in lithium. This work presents surface science studies of deuterium retention in lithium films as a function of surface temperature, incident deuterium ion energy and flux. Initial experiments are performed on thin (3-30 ML) lithium films deposited on a single crystal molybdenum substrate to avoid effects due to grain boundaries, intrinsic defects and impurities. A monoenergetic and mass-filtered deuterium ion beam was generated in a differentially pumped Colutron ion gun. Auger electron spectroscopy and X-ray photoelectron spectroscopy were used to identify the elemental composition and temperature programmed desorption was used to measure the deuterium retention under the different conditions. Support was provided through DOE Contract Number DE-AC02-09CH11466.

  12. Disassembly time of deuterium-cluster-fusion plasma irradiated by an intense laser pulse

    DOE PAGES

    Bang, W.

    2015-07-02

    Energetic deuterium ions from large deuterium clusters (>10 nm diameter) irradiated by an intense laser pulse (>10¹⁶ W/cm²) produce DD fusion neutrons for a time interval determined by the geometry of the resulting fusion plasma. We show an analytical solution of this time interval, the plasma disassembly time, for deuterium plasmas that are cylindrical in shape. Assuming a symmetrically expanding deuterium plasma, we calculate the expected fusion neutron yield and compare with an independent calculation of the yield using the concept of a finite confinement time at a fixed plasma density. The calculated neutron yields agree quantitatively with the availablemore » experimental data. Our one-dimensional simulations indicate that one could expect a tenfold increase in total neutron yield by magnetically confining a 10 - keV deuterium fusion plasma for 10 ns.« less

  13. Deuterium uptake and sputtering of simultaneous lithiated, boronized, and oxidized carbon surfaces irradiated by low-energy deuterium

    NASA Astrophysics Data System (ADS)

    Domínguez-Gutiérrez, F. J.; Krstić, P. S.; Allain, J. P.; Bedoya, F.; Islam, M. M.; Lotfi, R.; van Duin, A. C. T.

    2018-05-01

    We study the effects of deuterium irradiation on D-uptake by simultaneously boronized, lithiated, oxidized, and deuterated carbon surfaces. We present analysis of the bonding chemistry of D for various concentrations of boron, lithium, oxygen, and deuterium on carbon surfaces using molecular dynamics with reactive force field potentials, which are here adapted to include the interaction of boron and lithium. We calculate D retention and sputtering yields of each constituent of the Li-C-B-O mixture and discuss the role of oxygen in these processes. The extent of the qualitative agreement between new experimental data for B-C-O-D obtained in this paper and computational data is provided. As in the case of the Li-C-O system, comparative studies where experimental and computational data complement each other (in this case on the B-Li-C-O system) provide deeper insights into the mechanisms behind the role that O plays in the retention of D, a relevant issue in fusion machines.

  14. Structural Changes in the Vanadium Sample Surface Induced by Pulsed High-Temperature Deuterium Plasma and Deuterium Ion Fluxes

    NASA Astrophysics Data System (ADS)

    Borovitskaya, I. V.; Pimenov, V. N.; Gribkov, V. A.; Padukh, M.; Bondarenko, G. G.; Gaidar, A. I.; Paramonova, V. V.; Morozov, E. V.

    2017-11-01

    The structural changes in the vanadium sample surface are studied as functions of the conditions of irradiation by pulsed high-temperature deuterium plasma and deuterium ion fluxes in the Plasma Focus installation. It is found that processes of partial evaporation, melting, and crystallization of the surface layer of vanadium samples take place in the plasma flux power density range q = 108-1010 W/cm2 and the ion flux density range q = 1010-1012 W/cm2. The surface relief is wavelike. There are microcracks, gas-filled bubbles (blisters), and traces of fracture on the surface. The blisters are failed in the solid state. The character of blister fracture is similar to that observed during usual ion irradiation in accelerators. The samples irradiated at relatively low power density ( q = 107-108 W/cm2) demonstrate the ejection of microparticles (surface fragments) on the side facing plasma. This process is assumed to be due to the fact that the unloading wave formed in the sample-target volume reaches its irradiated surface. Under certain irradiation conditions (sample-anode distance, the number of plasma pulses), a block microstructure with block sizes of several tens of microns forms on the sample surfaces. This structure is likely to form via directional crack propagation upon cooling of a thin melted surface layer.

  15. Monte Carlo simulation of explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator.

    PubMed

    Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

    2014-12-01

    An explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator has been simulated using the Monte Carlo N-Particle Transport Code (MCNP5). Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma emission (10.82MeV) following radiative neutron capture by (14)N nuclei. The explosive detection system was built based on a fully high-voltage-shielded, axial D-D neutron generator with a radio frequency (RF) driven ion source and nominal yield of about 10(10) fast neutrons per second (E=2.5MeV). Polyethylene and paraffin were used as moderators with borated polyethylene and lead as neutron and gamma ray shielding, respectively. The shape and the thickness of the moderators and shields are optimized to produce the highest thermal neutron flux at the position of the explosive and the minimum total dose at the outer surfaces of the explosive detection system walls. In addition, simulation of the response functions of NaI, BGO, and LaBr3-based γ-ray detectors to different explosives is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. A definition of depletion of fish stocks

    USGS Publications Warehouse

    Van Oosten, John

    1949-01-01

    Attention was focused on the need of a common and better understanding of the term depletion as applied to the fisheries in order to eliminate if possible the existing inexactness of thought on the subject. Depletion has been confused at various times with at least ten different ideas associated with it but which, as has has heen pointed out, are not synonymous at all. In defining depletion we must recognize that the term represents a condition and must not he confounded with the cause (overfishing) that leads to this condition or with the symptoms that identify it. Depletion was defined as a reduction, through overfishing, in the level of abundance of the exploitable segment of a stock that prevents the realization of the maximum productive capacity.

  17. Depleted Uranium Uses Research and Development

    Science.gov Websites

    Documents News FAQs Internet Resources Glossary Home » DU Uses Depleted Uranium Uses Research & Uses | DUF6 Management | DUF6 Conversion Facility EISs | Documents News | FAQs | Internet Resources

  18. 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

  19. Deuterium kinetic isotope effects on the dissociation of a protein-fatty acid complex in the gas phase.

    PubMed

    Liu, Lan; Michelsen, Klaus; Kitova, Elena N; Schnier, Paul D; Brown, Alex; Klassen, John S

    2012-04-04

    Deuterium kinetic isotope effects (KIEs) are reported for the first time for the dissociation of a protein-ligand complex in the gas phase. Temperature-dependent rate constants were measured for the loss of neutral ligand from the deprotonated ions of the 1:1 complex of bovine β-lactoglobulin (Lg) and palmitic acid (PA), (Lg + PA)(n-) → Lg(n-) + PA, at the 6- and 7- charge states. At 25 °C, partial or complete deuteration of the acyl chain of PA results in a measurable inverse KIE for both charge states. The magnitude of the KIEs is temperature dependent, and Arrhenius analysis of the rate constants reveals that deuteration of PA results in a decrease in activation energy. In contrast, there is no measurable deuterium KIE for the dissociation of the (Lg + PA) complex in aqueous solution at pH 8. Deuterium KIEs were calculated using conventional transition-state theory with an assumption of a late dissociative transition state (TS), in which the ligand is free of the binding pocket. The vibrational frequencies of deuterated and non-deuterated PA in the gas phase and in various solvents (n-hexane, 1-chlorohexane, acetone, and water) were established computationally. The KIEs calculated from the corresponding differences in zero-point energies account qualitatively for the observation of an inverse KIE but do not account for the magnitude of the KIEs nor their temperature dependence. It is proposed that the dissociation of the (Lg + PA) complex in aqueous solution also proceeds through a late TS in which the acyl chain is extensively hydrated such that there is no significant differential change in the vibrational frequencies along the reaction coordinate and, consequently, no significant KIE.

  20. A new definition of maternal depletion syndrome.

    PubMed Central

    Winkvist, A; Rasmussen, K M; Habicht, J P

    1992-01-01

    BACKGROUND. Although the term "maternal depletion syndrome" has been commonly used to explain poor maternal and infant health, whether such a syndrome actually exists remains unclear. This uncertainty may be due to the lack of a clear definition of the syndrome and the absence of theoretical frameworks that account for the many factors related to reproductive nutrition. METHODS. We propose a new definition of maternal depletion syndrome within a framework that accounts for potential confounding factors. RESULTS. Our conceptual framework distinguishes between childbearing pattern and inadequate diet as causes of poor maternal health; hence, our definition of maternal depletion syndrome has both biological and practical meaning. The new definition is based on overall change in maternal nutritional status over one reproductive cycle in relation to possible depletion and repletion phases and in relation to initial nutritional status. CONCLUSIONS. The empirical application of this approach should permit the testing of the existence of maternal depletion syndrome in the developing world, and the distinction between populations where family planning will alleviate maternal depletion and those in which an improved diet is also necessary. PMID:1566948

  1. ANATOMY OF DEPLETED INTERPLANETARY CORONAL MASS EJECTIONS

    SciTech Connect

    Kocher, M.; Lepri, S. T.; Landi, E.

    We report a subset of interplanetary coronal mass ejections (ICMEs) containing distinct periods of anomalous heavy-ion charge state composition and peculiar ion thermal properties measured by ACE /SWICS from 1998 to 2011. We label them “depleted ICMEs,” identified by the presence of intervals where C{sup 6+}/C{sup 5+} and O{sup 7+}/O{sup 6+} depart from the direct correlation expected after their freeze-in heights. These anomalous intervals within the depleted ICMEs are referred to as “Depletion Regions.” We find that a depleted ICME would be indistinguishable from all other ICMEs in the absence of the Depletion Region, which has the defining property ofmore » significantly low abundances of fully charged species of helium, carbon, oxygen, and nitrogen. Similar anomalies in the slow solar wind were discussed by Zhao et al. We explore two possibilities for the source of the Depletion Region associated with magnetic reconnection in the tail of a CME, using CME simulations of the evolution of two Earth-bound CMEs described by Manchester et al.« less

  2. NMR measurements on the triumf polarized deuterium target

    NASA Astrophysics Data System (ADS)

    Wait, G. D.; Delheij, P. P. J.; Healey, D. C.

    1989-01-01

    The NMR system and the polarization measurements of the TRIUMF polarized deuterium target are described. The NMR tuned circuit is kept resonant at all frequencies to allow for a high gain in the rf amplifiers and to permit the measurement of the real part of the NMR signal. A Starburst (J-11) and an LSI-11 are used to process the NMR signal at a high sample rate. A synthesizer under the control of an 8085 based microprocessor (TRIMAC) provides the rf sweep. Vector polarizations between -0.33 and -0.40 were routinely achieved during a four week run in the TRIUMF M11 pion beamline with a statistical uncertainty of 3.4% and a systematic uncertainty of 5%.

  3. Ion-driven deuterium permeation through tungsten at high temperatures

    NASA Astrophysics Data System (ADS)

    Gasparyan, Yu. M.; Golubeva, A. V.; Mayer, M.; Pisarev, A. A.; Roth, J.

    2009-06-01

    The ion-driven permeation (IDP) through 50 μm thick pure tungsten foils was measured in the temperature range of 823-923 K during irradiation by 200 eV/D + ion beam with a flux of 10 17-10 18 D/m 2s. Gas driven permeation (GDP) from the deuterium background gas was observed as well. Calculations using both the analytical formula for the diffusion limited regime (DLR) and the TMAP 7 code gave good agreement with the experimental data. Defects with a detrapping energy of (2.05 ± 0.15) eV were found to limit the permeation lag time in our experimental conditions.

  4. Metal liner-driven quasi-isentropic compression of deuterium

    NASA Astrophysics Data System (ADS)

    Weinwurm, Marcus; Bland, Simon N.; Chittenden, Jeremy P.

    2013-09-01

    Properties of degenerate hydrogen and deuterium (D) at pressures of the order of terapascals are of key interest to Planetary Science and Inertial Confinement Fusion. In order to recreate these conditions in the laboratory, we present a scheme, where a metal liner drives a cylindrically convergent quasi-isentropic compression in a D fill. We first determined an external pressure history for driving a self-similar implosion of a D shell from a fictitious flow simulation [D. S. Clark and M. Tabak, Nucl. Fusion 47, 1147 (2007)]. Then, it is shown that this D implosion can be recreated inside a beryllium liner by shaping the current pulse. For a peak current of 10.8 MA cold and nearly isochoric D is assembled at around 12 500 kg/m3. Finally, our two-dimensional Gorgon simulations show the robustness of the implosion method to the magneto-Rayleigh-Taylor instability when using a sufficiently thick liner.

  5. Comparison of hydrogen and deuterium adsorption on Pd(100).

    PubMed

    Gladys, M J; Kambali, I; Karolewski, M A; Soon, A; Stampfl, C; O'Connor, D J

    2010-01-14

    Low energy ion recoil spectroscopy is a powerful technique for the determination of adsorbate position on metal surfaces. In this study, this technique is employed to compare the adsorption sites of hydrogen and deuterium on Pd(100) by detection of either H or D recoil ions produced by Ne(+) bombardment. Comparisons of experimental and Kalypso simulated azimuthal yield distributions show that, at room temperature, both hydrogen isotopes are adsorbed in the fourfold hollow site of Pd(100), however, at different heights above the surface (H-0.20 A and D-0.25 A). The adsorbates remain in the hollow site at all temperatures up to 383 K even though they move up to 0.40-0.45 A above the surface. Density functional theory calculations show a similar coverage dependent adsorption height for both H and D and confirm a real difference between the H and D adsorption heights based on zero point energies.

  6. Interstellar Processes Leading to Molecular Deuterium Enrichment and Their Detection

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; Kliss, Mark (Technical Monitor)

    2001-01-01

    Large deuterium (D) enrichments in meteoritic materials indicate that interstellar organic materials survived incorporation into parent bodies within the forming Solar System. These enrichments are likelier due to one or more of four distinct astrochemical processes. These are (1) low temperature gas phase ion-molecule reactions; (2) low temperature gas-grain reactions; (3) gas phase unimolecular photodissociation, and (4) ultraviolet photolysis in D-enriched ice mantles. Each of these processes should be associated with molecular carriers having, distinct regiochemical signatures (D placement on the product molecules, correlation with specific chemical functionalities, etc.). These processes are reviewed and specific spectroscopic signatures for the detection of these processes in space are identified and described.

  7. Deuterium Abundance in the Local ISM and Possible Spatial Variations

    NASA Technical Reports Server (NTRS)

    Linsky, Jeffrey L.

    1998-01-01

    Excellent HST/GHRS spectra of interstellar hydrogen and deuterium Lyman-(alpha) absorption toward nearby stars allow us to identify systematic errors that have plagued earlier work and to measure accurate values of the D/H ratio in local interstellar gas. Analysis of 12 sightlines through the Local Interstellar Cloud leads to a mean value of D/H = (1.50 +/- 0.10) x 10(exp -5) with all data points lying within +/- l(delta) of the mean. Whether or not the D/H ratio has different values elsewhere in the Galaxy and beyond is a very important open question that will be one of the major objectives of the Far Ultraviolet Spectroscopic Explorer (FUSE) mission.

  8. Deuterium sputtering of Li and Li-O films

    NASA Astrophysics Data System (ADS)

    Nelson, Andrew; Buzi, Luxherta; Kaita, Robert; Koel, Bruce

    2017-10-01

    Lithium wall coatings have been shown to enhance the operational plasma performance of many fusion devices, including NSTX and other tokamaks, by reducing the global wall recycling coefficient. However, pure lithium surfaces are extremely difficult to maintain in experimental fusion devices due to both inevitable oxidation and codeposition from sputtering of hot plasma facing components. Sputtering of thin lithium and lithium oxide films on a molybdenum target by energetic deuterium ion bombardment was studied in laboratory experiments conducted in a surface science apparatus. A Colutron ion source was used to produce a monoenergetic, mass-selected ion beam. Measurements were made under ultrahigh vacuum conditions as a function of surface temperature (90-520 K) using x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and temperature programmed desorption (TPD). Results are compared with computer simulations conducted on a temperature-dependent data-calibrated (TRIM) model.

  9. [Deuterium isotope characteristics of precipitation infiltrated in the West Ordos Desert of Inner Mongolia, China].

    PubMed

    Chen, Jie; Xu, Qing; Gao, De Qiang; Ma, Ying Bin; Zhang, Bei Bei; Hao, Yu Guang

    2017-07-18

    Understanding the soil-profile temporal and spatial distribution of rainwater in arid and semiarid regions provides a scientific basis for the restoration and maintenance of degraded desert ecosystems in the West Ordos Desert of Inner Mongolia, China. In this study, the deuterium isotope (δD) value of rainwater, soil water, and groundwater were examined in the West Ordos Desert. The contribution of precipitation to soil water in each layer of the soil profile was calculated with two-end linear mixed model. In addition, the temporal and spatial distribution of δD of soil water in the soil profile was analyzed under different-intensity precipitation. The results showed that small rainfall events (0-10 mm) affected the soil moisture and the δD value of soil water in surface soil (0-10 cm). About 30.3% to 87.9% of rainwater was kept in surface soil for nine days following the rainfall event. Medium rainfall events (10-20 mm) influenced the soil moisture and the δD value of soil water at soil depth of 0-40 cm. About 28.2% to 80.8% of rainwater was kept in soil layer of 0-40 cm for nine days following the medium rainfall event. Large (20-30 mm) and extremely large (>30 mm) rainfall events considerably influenced the soil moisture and δD value of soil water in each of the soil layers, except for the 100-150 cm layer. The δD value of soil water was between those δD values of rainwater and groundwater, which suggested that precipitation and groundwater were the sources of soil water in the West Ordos Desert. Under the same intensity rainfall, the δD value of surface soil water (0-10 cm) was directly affected by δD of rainwater. With increasing soil depth, the variation of soil water δD decreased, and the soil water of 100-150 cm kept stable. With increasing intensity of precipitation, the influence of precipitation on soil water δD lasted for a longer duration and occurred at a deeper soil depth.

  10. Cosmological and astrophysical consequences of a high primordial deuterium abundance

    NASA Astrophysics Data System (ADS)

    Vangioni-Flam, Elisabeth; Casse, Michel

    1995-03-01

    We explore the consequences of the first detection of deuterium in a high-redshift, very metal-poor absorbing cloud complex, D/H = (1.9-2.5) x 10-4, by Songaila et al. and Carswell et al., obtained with the Keck telescope. This value reflects closely the primordial abundance ratio provided that the observed spectral features are not due to the corruption of the signal by an errant hydrogen cloud of misfortunate velocity. Assuming that the measured D abundance is free from contamination, the baryon/photon ratio is now confined to the range 1.3-2 (instead of 3-4 and more), in both the classical and inhomogeneous big bangs. Other light elements (He-3, He-4 and Li-7) are consistent with these figures. The low baryonic density of the universe that ensues leaves no room for baryonic matter in the extended halos of elliptical galaxies, especially if the Hubble parameter is close to 100 km/s/Mpc. Nonbaryonic matter clearly dominates the gravitating mass of clusters of galaxies. The upper limit of the gas density at high redshift (before bulk galaxy formation) is now consistent with the baryonic one. A massive destruction of deuterium, in the course of the evolution of the galaxy (say, by a factor of 10-25) is required to match the D/H ratio observed in the local interstellar medium. The higher D destruction proposed up to now corresponds to galactic evolutionary models devised by Vangioni-Flam & Audouze (1988) and Vangioni-Flam, Olive, & Prantzos (1994). We discuss the virtues and the limits of this class of models and propose an alternative based on mass related to a galactic wind.

  11. Multiple Paths of Deuterium Fractionation in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Aikawa, Yuri; Furuya, Kenji; Hincelin, Ugo; Herbst, Eric

    2018-03-01

    We investigate deuterium chemistry coupled with the nuclear spin-state chemistry of H2 and {{{H}}}3+ in protoplanetary disks. Multiple paths of deuterium fractionation are found; exchange reactions with D atoms, such as HCO+ + D, are effective in addition to those with HD. In a disk model with grain sizes appropriate for dark clouds, the freeze-out of molecules is severe in the outer midplane, while the disk surface is shielded from UV radiation. Gaseous molecules, including DCO+, thus become abundant at the disk surface, which tends to make their column density distribution relatively flat. If the dust grains have grown to millimeter size, the freeze-out rate of neutral species is reduced and the abundances of gaseous molecules, including DCO+ and N2D+, are enhanced in the cold midplane. Turbulent diffusion transports D atoms and radicals at the disk surface to the midplane, and stable ice species in the midplane to the disk surface. The effects of turbulence on chemistry are thus multifold; while DCO+ and N2D+ abundances increase or decrease depending on the regions, HCN and DCN in the gas and ice are greatly reduced at the innermost radii, compared to the model without turbulence. When cosmic rays penetrate the disk, the ortho-to-para ratio (OPR) of H2 is found to be thermal in the disk, except in the cold (≲10 K) midplane. We also analyze the OPR of {{{H}}}3+ and H2D+, as well as the main reactions of H2D+, DCO+, and N2D+, in order to analytically derive their abundances in the cold midplane.

  12. Tritium, deuterium, and helium permeation through EPDM O-rings

    SciTech Connect

    Swansiger, W.A.

    1992-03-01

    This paper discusses tritium permeabilities determined at room temperature, 1.0 MPa (150 psia) tritium for three 23.4 cm diameter EPDM (ethylene-propylene-diene monomer) O-rings using a full-scale mock-up of the Al-SX shipping container seal geometry. The AL-SX container is being developed by Sandia National Laboratories for shipping tritium reservoirs. To determine the tritium permeation rate as a function of temperature, a 50.8 mm diameter EPDM O-ring was tested from room temperature to 150{degrees}C at a pressure of 1.0 MPa. Additional permeation measurements were made under the following test conditions: deuterium and helium-4 at room temperature and a pressure of 1.0 MPamore » using the full-scale AL-SX fixture, tritium from 0.1 MPa to 1.0 MPa at 142{degrees}C using the 50.8 mm fixture, and deuterium form room temperature to 150{degrees}C at a pressure of 1.0 MPa using the three full-scale O-rings showed the average room temperature, 1.0 MPa steady state tritium permeation rate to be about 1 {times} 10{sup {minus}2} Pa-liter/sec (7.6 {times} 10{sup {minus}5} torr-liter/sec or 1 {times} 10{sup {minus}4} std cc/sec), well within the allowable limit of 7.1 {times} 10{sup {minus}2} Pa-liter/sec for tritium release form the AL-SX container.« less

  13. Toxicology: Mechanisms of deuterium oxide action, part 2. [deuterium oxide effect on growth of winter rye

    NASA Technical Reports Server (NTRS)

    Siegel, S. M.

    1973-01-01

    The metabolism of winter rye seedlings (Secale cereale, L. cv. Winter) cultured in 99.6% D2O was investigated. Compared with water grown seedlings, the protein content was much lower in the D2O cultured seedlings and the incorporation of H(3)-leucine and H(3)-phenylalanine into medium to high molecular weight proteins was partially blocked. The synthesis of the enzyme peroxidase was also reduced in the D2O plants. Seedlings cultured in D2O incorporate H(3)-thymidine into DNA, but do not take up H(3)-uridine. These results suggest that some of the toxic effects of D2O culture on higher plants can be attributed to a partial block of protein synthesis.

  14. Deuterium Values from Hydrated Volcanic Glass: A Paleoelevation Proxy for Oregon's Cascade Range

    NASA Astrophysics Data System (ADS)

    Carlson, T. B.; Bershaw, J. T.; Cassel, E. J.

    2017-12-01

    Deuterium ratios (δD) of hydrated volcanic glass have been used to reconstruct Cenozoic paleoenvironments. However, the reliability and proper sample preparation protocol have been debated. The Cascades are an excellent location to study the validity of hydrated volcanic glass as a paleoelevation proxy for several reasons. Moisture is largely derived from a single oceanic source and falls as orographic precipitation in the Cascades, leading to a characteristic altitude effect, or inverse relationship between elevation and the isotopic composition of meteoric water (δD). Additionally, past studies have inferred uplift of the Cascades since the Miocene based on changing fossil assemblages, tectonic models, and other isotopic proxies including soil carbonates and fossil teeth. In this study, hydrated volcanic ash samples from the lee of the Cascades were rinsed with hydrochloric acid and sonicated before glass shards were hand-selected and analyzed for δD and wt. % water. These preliminary results exhibited δD values becoming enriched with time, a trend opposite of other paleowater proxy studies in the area. A possible explanation for this trend is contamination due to inadequate removal of materials adhered to shard surfaces that can readily exchange with environmental water. Recent research asserts that hydrofluoric acid (HF) etching during sample preparation is necessary to accurately measure δD values of syndepositional water. Volcanic ash samples were reanalyzed after preparation using HF abrasion and heavy liquid separation. The data from these two subsets are interpreted in the context of modern water across the range, as well as other paleowater proxy and geologic studies to determine the implications of volcanic glass as a paleoelevation proxy in the Pacific Northwest.

  15. 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.

  16. H{sub 2} Ortho-to-para Conversion on Grains: A Route to Fast Deuterium Fractionation in Dense Cloud Cores?

    SciTech Connect

    Bovino, S.; Grassi, T.; Schleicher, D. R. G.

    Deuterium fractionation, i.e., the enhancement of deuterated species with respect to non-deuterated ones, is considered to be a reliable chemical clock of star-forming regions. This process is strongly affected by the ortho-to-para H{sub 2} ratio. In this Letter we explore the effect of the ortho–para (o–p) H{sub 2} conversion on grains on the deuteration timescale in fully-depleted dense cores, including the most relevant uncertainties that affect this complex process. We show that (i) the o–p H{sub 2} conversion on grains is not strongly influenced by the uncertainties on the conversion time and the sticking coefficient, and (ii) that the processmore » is controlled by the temperature and the residence time of ortho-H{sub 2} on the surface, i.e., by the binding energy. We find that for binding energies between 330 and 550 K, depending on the temperature, the o–p H{sub 2} conversion on grains can shorten the deuterium fractionation timescale by orders of magnitude, opening a new route for explaining the large observed deuteration fraction D {sub frac} in dense molecular cloud cores. Our results suggest that the star formation timescale, when estimated through the timescale to reach the observed deuteration fractions, might be shorter than previously proposed. However, more accurate measurements of the binding energy are needed in order to better assess the overall role of this process.« less

  17. Depletion Mapping and Constrained Optimization to Support Managing Groundwater Extraction.

    PubMed

    Fienen, Michael N; Bradbury, Kenneth R; Kniffin, Maribeth; Barlow, Paul M

    2018-01-01

    Groundwater models often serve as management tools to evaluate competing water uses including ecosystems, irrigated agriculture, industry, municipal supply, and others. Depletion potential mapping-showing the model-calculated potential impacts that wells have on stream baseflow-can form the basis for multiple potential management approaches in an oversubscribed basin. Specific management approaches can include scenarios proposed by stakeholders, systematic changes in well pumping based on depletion potential, and formal constrained optimization, which can be used to quantify the tradeoff between water use and stream baseflow. Variables such as the maximum amount of reduction allowed in each well and various groupings of wells using, for example, K-means clustering considering spatial proximity and depletion potential are considered. These approaches provide a potential starting point and guidance for resource managers and stakeholders to make decisions about groundwater management in a basin, spreading responsibility in different ways. We illustrate these approaches in the Little Plover River basin in central Wisconsin, United States-home to a rich agricultural tradition, with farmland and urban areas both in close proximity to a groundwater-dependent trout stream. Groundwater withdrawals have reduced baseflow supplying the Little Plover River below a legally established minimum. The techniques in this work were developed in response to engaged stakeholders with various interests and goals for the basin. They sought to develop a collaborative management plan at a watershed scale that restores the flow rate in the river in a manner that incorporates principles of shared governance and results in effective and minimally disruptive changes in groundwater extraction practices. © 2017, National Ground Water Association.

  18. Investigation of the role of the micro-porous layer in polymer electrolyte fuel cells with hydrogen deuterium contrast neutron radiography.

    PubMed

    Cho, Kyu Taek; Mench, Matthew M

    2012-03-28

    In this study, the high resolution hydrogen-deuterium contrast radiography method was applied to elucidate the impact of the micro-porous layer (MPL) on water distribution in the porous fuel cell media. At the steady state, deuterium replaced hydrogen in the anode stream, and the large difference in neutron attenuation of the D(2)O produced at the cathode was used to track the produced water. It was found that the water content peaked in the cathode-side diffusion media (DM) for the cell without MPL, but with an MPL on the anode and cathode DM, the peak water amount was pushed toward the anode, resulting in a relatively flattened water profile through components and demonstrating a liquid barrier effect. Additionally, the dynamic water behavior in diffusion media was analyzed to understand the effect of a MPL and operating conditions. The water content in the DM changed with applied current, although there is a significant amount of residual liquid content that does not appear to be part of capillary channels. The effect of the MPL on irreducible saturation in DM and cell performance was also investigated.

  19. Evidence for Nuclear Tensor Polarization of Deuterium Molecules in Storage Cells

    SciTech Connect

    van den Brand, J.; Bulten, H.; Zhou, Z.

    1997-02-01

    Deuterium molecules were obtained by recombination, on a copper surface, of deuterium atoms prepared in specific hyperfine states. The molecules were stored for about 5ms in an open-ended cylindrical cell, placed in a 23mT magnetic field, and their tensor polarization was measured by elastic scattering of 704MeV electrons. The results of the measurements are consistent with the deuterium molecules retaining the tensor polarization of the initial atoms. {copyright} {ital 1997} {ital The American Physical Society}

  20. Late-stage magmatic outgassing from a volatile-depleted Moon.

    PubMed

    Day, James M D; Moynier, Frédéric; Shearer, Charles K

    2017-09-05

    The abundance of volatile elements and compounds, such as zinc, potassium, chlorine, and water, provide key evidence for how Earth and the Moon formed and evolved. Currently, evidence exists for a Moon depleted in volatile elements, as well as reservoirs within the Moon with volatile abundances like Earth's depleted upper mantle. Volatile depletion is consistent with catastrophic formation, such as a giant impact, whereas a Moon with Earth-like volatile abundances suggests preservation of these volatiles, or addition through late accretion. We show, using the "Rusty Rock" impact melt breccia, 66095, that volatile enrichment on the lunar surface occurred through vapor condensation. Isotopically light Zn (δ 66 Zn = -13.7‰), heavy Cl (δ 37 Cl = +15‰), and high U/Pb supports the origin of condensates from a volatile-poor internal source formed during thermomagmatic evolution of the Moon, with long-term depletion in incompatible Cl and Pb, and lesser depletion of more-compatible Zn. Leaching experiments on mare basalt 14053 demonstrate that isotopically light Zn condensates also occur on some mare basalts after their crystallization, confirming a volatile-depleted lunar interior source with homogeneous δ 66 Zn ≈ +1.4‰. Our results show that much of the lunar interior must be significantly depleted in volatile elements and compounds and that volatile-rich rocks on the lunar surface formed through vapor condensation. Volatiles detected by remote sensing on the surface of the Moon likely have a partially condensate origin from its interior.

  1. Depletion sensitivity predicts unhealthy snack purchases.

    PubMed

    Salmon, Stefanie J; Adriaanse, Marieke A; Fennis, Bob M; De Vet, Emely; De Ridder, Denise T D

    2016-01-01

    The aim of the present research is to examine the relation between depletion sensitivity - a novel construct referring to the speed or ease by which one's self-control resources are drained - and snack purchase behavior. In addition, interactions between depletion sensitivity and the goal to lose weight on snack purchase behavior were explored. Participants included in the study were instructed to report every snack they bought over the course of one week. The dependent variables were the number of healthy and unhealthy snacks purchased. The results of the present study demonstrate that depletion sensitivity predicts the amount of unhealthy (but not healthy) snacks bought. The more sensitive people are to depletion, the more unhealthy snacks they buy. Moreover, there was some tentative evidence that this relation is more pronounced for people with a weak as opposed to a strong goal to lose weight, suggesting that a strong goal to lose weight may function as a motivational buffer against self-control failures. All in all, these findings provide evidence for the external validity of depletion sensitivity and the relevance of this construct in the domain of eating behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Drought response strategies define the relative contributions of hydraulic dysfunction and carbohydrate depletion during tree mortality.

    PubMed

    Mitchell, Patrick J; O'Grady, Anthony P; Tissue, David T; White, Donald A; Ottenschlaeger, Maria L; Pinkard, Elizabeth A

    2013-02-01

    Plant survival during drought requires adequate hydration in living tissues and carbohydrate reserves for maintenance and recovery. We hypothesized that tree growth and hydraulic strategy determines the intensity and duration of the 'physiological drought', thereby affecting the relative contributions of loss of hydraulic function and carbohydrate depletion during mortality. We compared patterns in growth rate, water relations, gas exchange and carbohydrate dynamics in three tree species subjected to prolonged drought. Two Eucalyptus species (E. globulus, E. smithii) exhibited high growth rates and water-use resulting in rapid declines in water status and hydraulic conductance. In contrast, conservative growth and water relations in Pinus radiata resulted in longer periods of negative carbon balance and significant depletion of stored carbohydrates in all organs. The ongoing demand for carbohydrates from sustained respiration highlighted the role that duration of drought plays in facilitating carbohydrate consumption. Two drought strategies were revealed, differentiated by plant regulation of water status: plants maximized gas exchange, but were exposed to low water potentials and rapid hydraulic dysfunction; and tight regulation of gas exchange at the cost of carbohydrate depletion. These findings provide evidence for a relationship between hydraulic regulation of water status and carbohydrate depletion during terminal drought. © 2012 CSIRO. New Phytologist © 2012 New Phytologist Trust.

  3. Ego depletion in visual perception: Ego-depleted viewers experience less ambiguous figure reversal.

    PubMed

    Wimmer, Marina C; Stirk, Steven; Hancock, Peter J B

    2017-10-01

    This study examined the effects of ego depletion on ambiguous figure perception. Adults (N = 315) received an ego depletion task and were subsequently tested on their inhibitory control abilities that were indexed by the Stroop task (Experiment 1) and their ability to perceive both interpretations of ambiguous figures that was indexed by reversal (Experiment 2). Ego depletion had a very small effect on reducing inhibitory control (Cohen's d = .15) (Experiment 1). Ego-depleted participants had a tendency to take longer to respond in Stroop trials. In Experiment 2, ego depletion had small to medium effects on the experience of reversal. Ego-depleted viewers tended to take longer to reverse ambiguous figures (duration to first reversal) when naïve of the ambiguity and experienced less reversal both when naïve and informed of the ambiguity. Together, findings suggest that ego depletion has small effects on inhibitory control and small to medium effects on bottom-up and top-down perceptual processes. The depletion of cognitive resources can reduce our visual perceptual experience.

  4. The modality effect of ego depletion: Auditory task modality reduces ego depletion.

    PubMed

    Li, Qiong; Wang, Zhenhong

    2016-08-01

    An initial act of self-control that impairs subsequent acts of self-control is called ego depletion. The ego depletion phenomenon has been observed consistently. The modality effect refers to the effect of the presentation modality on the processing of stimuli. The modality effect was also robustly found in a large body of research. However, no study to date has examined the modality effects of ego depletion. This issue was addressed in the current study. In Experiment 1, after all participants completed a handgrip task, one group's participants completed a visual attention regulation task and the other group's participants completed an auditory attention regulation task, and then all participants again completed a handgrip task. The ego depletion phenomenon was observed in both the visual and the auditory attention regulation task. Moreover, participants who completed the visual task performed worse on the handgrip task than participants who completed the auditory task, which indicated that there was high ego depletion in the visual task condition. In Experiment 2, participants completed an initial task that either did or did not deplete self-control resources, and then they completed a second visual or auditory attention control task. The results indicated that depleted participants performed better on the auditory attention control task than the visual attention control task. These findings suggest that altering task modality may reduce ego depletion. © 2016 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  5. Self-regulation, ego depletion, and inhibition.

    PubMed

    Baumeister, Roy F

    2014-12-01

    Inhibition is a major form of self-regulation. As such, it depends on self-awareness and comparing oneself to standards and is also susceptible to fluctuations in willpower resources. Ego depletion is the state of reduced willpower caused by prior exertion of self-control. Ego depletion undermines inhibition both because restraints are weaker and because urges are felt more intensely than usual. Conscious inhibition of desires is a pervasive feature of everyday life and may be a requirement of life in civilized, cultural society, and in that sense it goes to the evolved core of human nature. Intentional inhibition not only restrains antisocial impulses but can also facilitate optimal performance, such as during test taking. Self-regulation and ego depletion- may also affect less intentional forms of inhibition, even chronic tendencies to inhibit. Broadly stated, inhibition is necessary for human social life and nearly all societies encourage and enforce it. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Ozone depletion and chlorine loading potentials

    NASA Technical Reports Server (NTRS)

    Pyle, John A.; Wuebbles, Donald J.; Solomon, Susan; Zvenigorodsky, Sergei; Connell, Peter; Ko, Malcolm K. W.; Fisher, Donald A.; Stordal, Frode; Weisenstein, Debra

    1991-01-01

    The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

  7. Aberrations in stimulated emission depletion (STED) microscopy

    NASA Astrophysics Data System (ADS)

    Antonello, Jacopo; Burke, Daniel; Booth, Martin J.

    2017-12-01

    Like all methods of super-resolution microscopy, stimulated emission depletion (STED) microscopy can suffer from the effects of aberrations. The most important aspect of a STED microscope is that the depletion focus maintains a minimum, ideally zero, intensity point that is surrounded by a region of higher intensity. It follows that aberrations that cause a non-zero value of this minimum intensity are the most detrimental, as they inhibit fluorescence emission even at the centre of the depletion focus. We present analysis that elucidates the nature of these effects in terms of the different polarisation components at the focus for two-dimensional and three-dimensional STED resolution enhancement. It is found that only certain low-order aberration modes can affect the minimum intensity at the Gaussian focus. This has important consequences for the design of adaptive optics aberration correction systems.

  8. Radionuclide inventories : ORIGEN2.2 isotopic depletion calculation for high burnup low-enriched uranium and weapons-grade mixed-oxide pressurized-water reactor fuel assemblies.

    SciTech Connect

    Gauntt, Randall O.; Ross, Kyle W.; Smith, James Dean

    2010-04-01

    The Oak Ridge National Laboratory computer code, ORIGEN2.2 (CCC-371, 2002), was used to obtain the elemental composition of irradiated low-enriched uranium (LEU)/mixed-oxide (MOX) pressurized-water reactor fuel assemblies. Described in this report are the input parameters for the ORIGEN2.2 calculations. The rationale for performing the ORIGEN2.2 calculation was to generate inventories to be used to populate MELCOR radionuclide classes. Therefore the ORIGEN2.2 output was subsequently manipulated. The procedures performed in this data reduction process are also described herein. A listing of the ORIGEN2.2 input deck for two-cycle MOX is provided in the appendix. The final output from this data reduction processmore » was three tables containing the radionuclide inventories for LEU/MOX in elemental form. Masses, thermal powers, and activities were reported for each category.« less

  9. Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility.

    PubMed

    Döppner, T; Callahan, D A; Hurricane, O A; Hinkel, D E; Ma, T; Park, H-S; Berzak Hopkins, L F; Casey, D T; Celliers, P; Dewald, E L; Dittrich, T R; Haan, S W; Kritcher, A L; MacPhee, A; Le Pape, S; Pak, A; Patel, P K; Springer, P T; Salmonson, J D; Tommasini, R; Benedetti, L R; Bond, E; Bradley, D K; Caggiano, J; Church, J; Dixit, S; Edgell, D; Edwards, M J; Fittinghoff, D N; Frenje, J; Gatu Johnson, M; Grim, G; Hatarik, R; Havre, M; Herrmann, H; Izumi, N; Khan, S F; Kline, J L; Knauer, J; Kyrala, G A; Landen, O L; Merrill, F E; Moody, J; Moore, A S; Nikroo, A; Ralph, J E; Remington, B A; Robey, H F; Sayre, D; Schneider, M; Streckert, H; Town, R; Turnbull, D; Volegov, P L; Wan, A; Widmann, K; Wilde, C H; Yeamans, C

    2015-07-31

    We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a "high-foot" laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shape closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10^{16} neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.

  10. Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility

    SciTech Connect

    Döppner, T.; Callahan, D. A.; Hurricane, O. A.

    We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a “highfoot” laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shapemore » closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10 16 neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.« less

  11. Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility

    DOE PAGES

    Döppner, T.; Callahan, D. A.; Hurricane, O. A.; ...

    2015-07-28

    We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a “highfoot” laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shapemore » closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10 16 neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.« less

  12. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means any...

  13. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means any...

  14. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 2 2014-10-01 2014-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means any...

  15. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means any...

  16. 48 CFR 52.223-11 - Ozone-Depleting Substances.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Ozone-Depleting Substances....223-11 Ozone-Depleting Substances. As prescribed in 23.804(a), insert the following clause: Ozone-Depleting Substances (MAY 2001) (a) Definition. Ozone-depleting substance, as used in this clause, means any...

  17. Hydrogen And Deuterium In The Local Interstellar Medium.

    NASA Astrophysics Data System (ADS)

    Murthy, Jayant

    2016-03-01

    In this work we report on the results of a series of IUE observations of interstellar HI and DI Ly alpha absorption against the chromospheric Lyalpha emission of the nearby late -type stars alpha Cen B(1.3 pc), epsilon Eri (3.3 pc), Procyon (3.5 pc), Altair (5.1 pc), Capella (13.2 pc), and HR 1099 (33 pc). From these observations we have derived the density, velocity dispersion, and bulk velocity of the neutral hydrogen along the line of sight to each of these stars. We have also placed lower limits on the deuterium to hydrogen (D/H) ratio towards the same stars. Our IUE results are generally consistent with previous observations of the same stars with the Copernicus satellite showing that our modelling procedure is independent of stellar variations over a period of several years. The HI absorption profile towards Altair shows a broad saturated core and steep line wings, consistent with a multicomponent interstellar medium in that direction. The bulk velocities towards the other stars are consistent with a bulk flow from the approximate direction of the galactic center but do show local variations from a uniform flow, possibly indicating a complicated velocity structure even in the solar neighbourhood. Interstellar deuterium is detected towards every star except Altair and the derived values for the D/H ratio are consistent with those previously found with Copernicus. In particular, we confirm the strong lower limit of 1.9 times 10^{-5} on the D/H ratio found towards Capella and we also place a lower limit of 1.5 times 10 ^{-5} on the D/H ratio towards alpha Cen B. Although an interstellar D/H ratio of 2 times 10^ {-5} is consistent with all the observations of late-type stars, the lower D/H ratios found towards several hot stars may indicate real variations in the D/H ratio in the local interstellar medium. Finally, we discuss the reality of a step in the cosmic background and of several galactic emission lines found by Auriemma et al. (1984) and show that, in

  18. Deuterium diffusion and retention in tungsten coated with barrier layer during ion irradiation

    NASA Astrophysics Data System (ADS)

    Begrambekov, L. B.; Kaplevsky, A. S.; Dovganyuk, S. S.; Evsin, A. E.; Baryshnikova, I. E.

    2017-12-01

    The results of the comparative analysis of low-temperature desorption of deuterium from tungsten coated with aluminum and yttrium films under the irradiation by hydrogen plasma with oxygen impurity are presented. The irradiation of aluminum or yttrium coating by H2+1%O2 plasma leads to the desorption of implanted deuterium from the samples. It was shown that the number of atoms desorbed depends on the sign of enthalpy of hydrogen solution in the metal film.

  19. Depletion Rate of Hydrogen Peroxide from Sodium Perborate Bleaching Agent.

    PubMed

    Tran, Liliann; Orth, Rebecca; Parashos, Peter; Tao, Ying; Tee, Calvin W J; Thomas, Vineet Thenalil; Towers, Georgina; Truong, Diem Thuy; Vinen, Cynthia; Reynolds, Eric C

    2017-03-01

    Internal bleaching of discolored teeth uses sodium perborate reacting with water to form the active agent, hydrogen peroxide (H 2 O 2 ). Sodium perborate is replaced at varying time intervals depending on clinician preference and until esthetically acceptable results are achieved, but this is done without scientific basis. This study measured the depletion rate of hydrogen peroxide from sodium perborate as a bleaching agent. Two sodium perborate bleaching products (Odontobleach [Australian Dental Manufacturing, Kenmore Hills, Queensland, Australia] and Endosure Perborate Micro [Dentalife, Ringwood, Victoria, Australia]) and distilled deionized water mixtures at ratios of 25 μg/mL, 50 μg/mL, and 100 μg/mL were placed into sealed microtubes and incubated at 37°C. H 2 O 2 concentrations were measured at 23 time points over 4 weeks. Quantification of H 2 O 2 concentrations was obtained using a ferrothiocyanate oxidation reduction reaction followed by spectrophotometry readings. The H 2 O 2 concentration rapidly peaked within 27 hours and reached a plateau by about 3 days (75 hours). Low levels of H 2 O 2 were evident beyond 3 days and for at least 28 days. No significant differences were found between the 2 sodium perborate products. There was also no significant difference in the depletion rate between the different ratios. Based on the chemistry of H 2 O 2 depletion, the minimum replacement interval for the bleaching agent is 3 days. Frequent replacements of the perborate clinically may be unnecessary because of the continued presence of low H 2 O 2 levels for at least 28 days. Although these data cannot be extrapolated to the clinical situation, they set a baseline for further studies to address the many clinical variables influencing internal bleaching. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. Depletion mapping and constrained optimization to support managing groundwater extraction

    USGS Publications Warehouse

    Fienen, Michael N.; Bradbury, Kenneth R.; Kniffin, Maribeth; Barlow, Paul M.

    2018-01-01

    Groundwater models often serve as management tools to evaluate competing water uses including ecosystems, irrigated agriculture, industry, municipal supply, and others. Depletion potential mapping—showing the model-calculated potential impacts that wells have on stream baseflow—can form the basis for multiple potential management approaches in an oversubscribed basin. Specific management approaches can include scenarios proposed by stakeholders, systematic changes in well pumping based on depletion potential, and formal constrained optimization, which can be used to quantify the tradeoff between water use and stream baseflow. Variables such as the maximum amount of reduction allowed in each well and various groupings of wells using, for example, K-means clustering considering spatial proximity and depletion potential are considered. These approaches provide a potential starting point and guidance for resource managers and stakeholders to make decisions about groundwater management in a basin, spreading responsibility in different ways. We illustrate these approaches in the Little Plover River basin in central Wisconsin, United States—home to a rich agricultural tradition, with farmland and urban areas both in close proximity to a groundwater-dependent trout stream. Groundwater withdrawals have reduced baseflow supplying the Little Plover River below a legally established minimum. The techniques in this work were developed in response to engaged stakeholders with various interests and goals for the basin. They sought to develop a collaborative management plan at a watershed scale that restores the flow rate in the river in a manner that incorporates principles of shared governance and results in effective and minimally disruptive changes in groundwater extraction practices.

  1. Comparison of circulation times of thermal waters discharging from the Idaho batholith based on geothermometer temperatures, helium concentrations, and 14C measurements

    USGS Publications Warehouse

    Mariner, R.H.; Evans, William C.; Young, H.W.

    2006-01-01

    Circulation times of waters in geothermal systems are poorly known. In this study, we examine the thermal waters of the Idaho batholith to verify whether maximum system temperatures, helium concentrations, and 14C values are related to water age in these low-to-moderate temperature geothermal systems. He/N2 values of gas collected from thermal waters that circulate solely through distinct units of the Idaho batholith correlate linearly with Na-K-(4/3)Ca geothermometer temperatures, showing that both variables are excellent indicators of relative water age. Thermal waters that circulate in early Tertiary (45-50 Ma) granite of the Sawtooth batholith have 3.5 times more helium than thermal waters of the same aquifer temperature that circulate through the main Cretaceous granite (average 91 Ma). Hot spring waters circulating in hydrothermally altered parts of the batholith have very little dissolved helium and no correlation between He/N2 values and geothermometer temperatures. Thermal waters discharging from the Idaho batholith are more depleted in deuterium than modern precipitation in the area. Recharge to these geothermal systems occurred from at least 10,000 BP for the cooler systems up to about 33,000 BP for the hotter systems.

  2. Promoting crystallisation of the Salmonella enteritidis fimbriae 14 pilin SefD using deuterium oxide

    SciTech Connect

    Liu, Bing; Garnett, James A.; Lee, Wei-chao

    Highlights: Black-Right-Pointing-Pointer The benefits of D{sub 2}O in screening for crystallisation was explored. Black-Right-Pointing-Pointer The crystal structures of the SefD pilin in both H{sub 2}O and D{sub 2}O reveal differences. Black-Right-Pointing-Pointer Crystallisation improvements are explained by altered interactions in D{sub 2}O crystals. Black-Right-Pointing-Pointer D{sub 2}O is useful additive in sparse-matrix screening for crystallisation. -- Abstract: The use of heavy water (D{sub 2}O) as a solvent is commonplace in many spectroscopic techniques for the study of biological macromolecules. A significant deuterium isotope effect exists where hydrogen-bonding is important, such as in protein stability, dynamics and assembly. Here we illustrate the usemore » of D{sub 2}O in additive screening for the production of reproducible diffraction-quality crystals for the Salmonella enteritidis fimbriae 14 (SEF14) putative tip adhesin, SefD.« less

  3. Quantitative assessment of brain glucose metabolic rates using in vivo deuterium magnetic resonance spectroscopy.

    PubMed

    Lu, Ming; Zhu, Xiao-Hong; Zhang, Yi; Mateescu, Gheorghe; Chen, Wei

    2017-11-01

    Quantitative assessment of cerebral glucose consumption rate (CMR glc ) and tricarboxylic acid cycle flux (V TCA ) is crucial for understanding neuroenergetics under physiopathological conditions. In this study, we report a novel in vivo Deuterium ( 2 H) MRS (DMRS) approach for simultaneously measuring and quantifying CMR glc and V TCA in rat brains at 16.4 Tesla. Following a brief infusion of deuterated glucose, dynamic changes of isotope-labeled glucose, glutamate/glutamine (Glx) and water contents in the brain can be robustly monitored from their well-resolved 2 H resonances. Dynamic DMRS glucose and Glx data were employed to determine CMR glc and V TCA concurrently. To test the sensitivity of this method in response to altered glucose metabolism, two brain conditions with different anesthetics were investigated. Increased CMR glc (0.46 vs. 0.28 µmol/g/min) and V TCA (0.96 vs. 0.6 µmol/g/min) were found in rats under morphine as compared to deeper anesthesia using 2% isoflurane. This study demonstrates the feasibility and new utility of the in vivo DMRS approach to assess cerebral glucose metabolic rates at high/ultrahigh field. It provides an alternative MRS tool for in vivo study of metabolic coupling relationship between aerobic and anaerobic glucose metabolisms in brain under physiopathological states.

  4. Enhancement of deuterium retention in damaged tungsten by plasma-induced defect clustering

    NASA Astrophysics Data System (ADS)

    Jin, Younggil; Roh, Ki-Baek; Sheen, Mi-Hyang; Kim, Nam-Kyun; Song, Jaemin; Kim, Young-Woon; Kim, Gon-Ho

    2017-12-01

    The enhancement of deuterium retention was investigated for tungsten in the presence of both 2.8 MeV self-ion induced cascade damage and fuel hydrogen isotope plasma. Vacancy clustering in cascade damaged polycrystalline tungsten occurred due to deuterium irradiation and was observed near the grain boundary by using all-step transmission electron microscopy analysis. Analysis of the highest desorption temperature peak using thermal desorption spectroscopy supports reasonable evidence of defect clustering in the damaged polycrystalline tungsten. The defect clustering was neither observed on the damaged polycrystalline tungsten without deuterium irradiation nor on the damaged single-crystalline tungsten with deuterium irradiation. This result implies the synergetic role of deuterium and grain boundary on defect clustering. This study proposes a path for the defect transform from point defect to defect cluster, by the agglomeration between irradiated deuterium and cascade damage-induced defect. This agglomeration may induce more severe damage on the tungsten divertor at which the high fuel hydrogen ions, fast neutrons, and self-ions are irradiated simultaneously and it would increase the in-vessel tritium inventory.

  5. “When the going gets tough, who keeps going?” Depletion sensitivity moderates the ego-depletion effect

    PubMed Central

    Salmon, Stefanie J.; Adriaanse, Marieke A.; De Vet, Emely; Fennis, Bob M.; De Ridder, Denise T. D.

    2014-01-01

    Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In three studies, we assessed individual differences in depletion sensitivity, and demonstrate that depletion sensitivity moderates ego-depletion effects. The Depletion Sensitivity Scale (DSS) was employed to assess depletion sensitivity. Study 1 employs the DSS to demonstrate that individual differences in sensitivity to ego-depletion exist. Study 2 shows moderate correlations of depletion sensitivity with related self-control concepts, indicating that these scales measure conceptually distinct constructs. Study 3 demonstrates that depletion sensitivity moderates the ego-depletion effect. Specifically, participants who are sensitive to depletion performed worse on a second self-control task, indicating a stronger ego-depletion effect, compared to participants less sensitive to depletion. PMID:25009523

  6. Transition duration of ingested deuterium oxide to eccrine sweat during exercise in the heat.

    PubMed

    Church, Adam; Lee, Fanny; Buono, Michael J

    2017-01-01

    The time necessary for the initial appearance of ingested water as sweat during exercise in the heat remains unknown. Based on the current literature, we estimated fluid transition through the body, from ingestion to appearance as sweat, to have a minimum time duration of approximately three minutes. The purpose of this study was to test this prediction and identify the time necessary for the initial enrichment of deuterium oxide (D 2 O) in sweat following ingestion during exercise in the heat. Eight participants performed moderate intensity (40% of maximal oxygen uptake) treadmill exercise in an environmental chamber (40°C, 40% rH) to induce active sweating. After fifteen minutes, while continuing to walk, participants consumed D 2 O (0.15mlkg -1 ) in a final volume of 50ml water. Scapular sweat samples were collected one minute prior to and ten minutes post-ingestion. Samples were analyzed for sweat D 2 O concentration using isotope ratio mass spectrometry and compared to baseline. Mean±SD ∆ sweat D 2 O concentration at minutes one and two post-ingestion were not significantly higher than baseline (0min). Minutes three (9±3ppm) through ten (23±11ppm) post-ingestion had ∆ sweat D 2 O concentrations significantly (P<0.05) higher than baseline. Such results suggest that ingested water rapidly transports across the mucosal membrane of the alimentary canal into the vasculature space, enters the extravascular fluid, and is actively secreted by the eccrine sweat glands onto the surface of the skin for potential evaporation in as little as three minutes during exercise in the heat. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Direct Visualization of an Impurity Depletion Zone

    NASA Technical Reports Server (NTRS)

    Chernov, Alex A.; Garcia-Ruiz, Juan Ma; Thomas, Bill R.

    2000-01-01

    When a crystal incorporates more impurity per unit of its volume than the impurity concentration in solution, the solution in vicinity of the growing crystal is depleted with respect to the impurity I,2. With a stagnant solution, e. g. in microgravity or gels, an impurity depletion zone expands as the crystal grows and results in greater purity in most of the outer portion of the crystal than in the core. Crystallization in gel provides an opportunity to mimic microgravity conditions and visualize the impurity depletion zone. Colorless, transparent apoferritin (M congruent to 450 KDa) crystals were grown in the presence of red holoferritin dimer as a microheterogeneous impurity (M congruent to 900 KDa) within agarose gel by counterdiffusion with Cd(2+) precipitant. Preferential trapping of dimers, (distribution coefficient K = 4 (exp 1,2)) results in weaker red color around the crystals grown in the left tube in the figure as compared to the control middle tube without crystals. The left and the middle tubes contain colored ferritin dimers, the right tube contains colored trimers. The meniscus in the left tube separate gel (below) and liquid solution containing Cd(2+) (above). Similar solutions, though without precipitants, were present on top of the middle and right tube allowing diffusion of dimers and trimers. The area of weaker color intensity around crystals directly demonstrates overlapped impurity depletion zones.

  8. Global Warming: Lessons from Ozone Depletion

    ERIC Educational Resources Information Center

    Hobson, Art

    2010-01-01

    My teaching and textbook have always covered many physics-related social issues, including stratospheric ozone depletion and global warming. The ozone saga is an inspiring good-news story that's instructive for solving the similar but bigger problem of global warming. Thus, as soon as students in my physics literacy course at the University of…

  9. Evolution of depleted mantle: The lead perspective

    NASA Astrophysics Data System (ADS)

    Tilton, George R.

    1983-07-01

    Isotopic data have established that, compared to estimated bulk earth abundances, the sources of oceanic basaltic lavas have been depleted in large ion lithophile elements for at least several billions of years. Various data on the Tertiary-Mesozoic Gorgona komatiite and Cretaceous Oka carbonatite show that those rocks also sample depleted mantle sources. This information is used by analogy to compare Pb isotopic data from 2.6 billion year old komatiite and carbonatite from the Suomussalmi belt of eastern Finland and Munro Township, Ontario that are with associated granitic rocks and ores that should contain marked crustal components. Within experimental error no differences are detected in the isotopic composition of initial Pb in either of the rock suites. These observations agree closely with Sr and Nd data from other laboratories showing that depleted mantle could not have originated in those areas more than a few tenths of billions of years before the rocks were emplaced. On a world-wide basis the Pb isotope data are consistent with production of depleted mantle by continuous differentiation processes acting over approximately the past 3 billion years. The data show that Pb evolution is more complex than the simpler models derived from the Rb-Sr and Sm-Nd systems. The nature of the complexity is still poorly understood.

  10. Soil moisture depletion patterns around scattered trees

    Treesearch

    Robert R. Ziemer

    1968-01-01

    Soil moisture was measured around an isolated mature sugar pine tree (Pinus lambertiana Dougl.) in the mixed conifer forest type of the north central Sierra Nevada, California, from November 1965 to October 1966. From a sequence of measurements, horizontal and vertical soil moisture profiles were developed. Estimated soil moisture depletion from the 61-foot radius plot...

  11. Equation of State Measurements of Deuterium up to 2 Mbar

    NASA Astrophysics Data System (ADS)

    Collins, G. W.

    1997-04-01

    While the hydrogen Equation of State at high density and temperature is integral to many astrophysical and planetary models, few experimental techniques can access the strongly-coupled region where molecular dissociation or electronic excitation occur. High power lasers can access much of this unexplored phase space. We(This work was done in collaboration with L. B. Da Silva, P. Celliers, K. S. Budil, R. Cauble, N. C. Holmes, T. W. Barbee Jr, B. A. Hammel, J. D. Kilkenny, R. J. Wallace, M. Ross, A. Ng and G. Chiu.) present the pressure (from 0.25 to 2.1 Mbar) and density on the first Hugoniot, derived from shock speed, particle speed, and compression measurements of liquid deuterium. Shock waves were produced with the Nova laser. The data show a significant increase in compressibility near 1 Mbar compared to existing widely-used equation of state models. The data are consistent with a thermal molecular dissociation of the diatomic fluid into a monatomic phase.

  12. Reduced deuterium retention in simultaneously damaged and annealed tungsten

    NASA Astrophysics Data System (ADS)

    Simmonds, M. J.; Wang, Y. Q.; Barton, J. L.; Baldwin, M. J.; Yu, J. H.; Doerner, R. P.; Tynan, G. R.

    2017-10-01

    Deuterium (D) retention in polycrystalline tungsten (W) with copper (Cu) ion damage concurrently produced at elevated surface temperature is investigated. An in situ heated stage held W samples at a controlled temperature up to 1243 K, which were subjected to displacement damage produced by 3.4 MeV Cu ions. D retention is subsequently explored by exposure of the W samples held at 383 K to a D2 plasma ion fluence of 1024 D+/m2. Nuclear reaction analysis (NRA), utilizing the D(3He,p)4He nuclear reaction, is used to probe the D concentration in the near surface up to 6 μm. Thermal desorption spectroscopy (TDS) is used to measure outgassed HD and D2 molecules to determine the bulk D concentration. Both NRA and TDS measure a significant reduction in D retention for samples damaged at elevated temperature. TDS quantitatively shows that the lowest energy trap remains largely unaffected while higher energy traps, induced by Cu ions, are annealed and approach intrinsic concentrations as the temperature during ion damage approaches 1243 K. Analysis of TDS data yields an activation energy of (0.10 ± 0.02) eV for recovery of ion-damage induced traps at elevated temperature.

  13. Deuterium-tritium experiments on the Tokamak Fusion Test reactor

    SciTech Connect

    Hosea, J.; Adler, J.H.; Alling, P.

    The deuterium-tritium (D-T) experimental program on the Tokamak Fusion Test Reactor (TFTR) is underway and routine tritium operations have been established. The technology upgrades made to the TFTR facility have been demonstrated to be sufficient for supporting both operations and maintenance for an extended D-T campaign. To date fusion power has been increased to {approx}9 MW and several physics results of importance to the D-T reactor regime have been obtained: electron temperature, ion temperature, and plasma stored energy all increase substantially in the D-T regime relative to the D-D regime at the same neutral beam power and comparable limiter conditioning;more » possible alpha electron heating is indicated and energy confinement improvement with average ion mass is observed; and alpha particle losses appear to be classical with no evidence of TAE mode activity up to the PFUS {approx}6 MW level. Instability in the TAE mode frequency range has been observed at PFUS > 7 MW and its effect on performance in under investigation. Preparations are underway to enhance the alpha particle density further by increasing fusion power and by extending the neutral beam pulse length to permit alpha particle effects of relevance to the ITER regime to be more fully explored.« less

  14. Deuterium results at the negative ion source test facility ELISE

    NASA Astrophysics Data System (ADS)

    Kraus, W.; Wünderlich, D.; Fantz, U.; Heinemann, B.; Bonomo, F.; Riedl, R.

    2018-05-01

    The ITER neutral beam system will be equipped with large radio frequency (RF) driven negative ion sources, with a cross section of 0.9 m × 1.9 m, which have to deliver extracted D- ion beams of 57 A at 1 MeV for 1 h. On the extraction from a large ion source experiment test facility, a source of half of this size is being operational since 2013. The goal of this experiment is to demonstrate a high operational reliability and to achieve the extracted current densities and beam properties required for ITER. Technical improvements of the source design and the RF system were necessary to provide reliable operation in steady state with an RF power of up to 300 kW. While in short pulses the required D- current density has almost been reached, the performance in long pulses is determined in particular in Deuterium by inhomogeneous and unstable currents of co-extracted electrons. By application of refined caesium evaporation and distribution procedures, and reduction and symmetrization of the electron currents, considerable progress has been made and up to 190 A/m2 D-, corresponding to 66% of the value required for ITER, have been extracted for 45 min.

  15. Reduced deuterium retention in simultaneously damaged and annealed tungsten

    DOE PAGES

    Simmonds, M. J.; Wang, Y. Q.; Barton, J. L.; ...

    2017-06-24

    Deuterium (D) retention in polycrystalline tungsten (W) with copper (Cu) ion damage concurrently produced at elevated surface temperature is investigated in this paper. An in situ heated stage held W samples at a controlled temperature up to 1243 K, which were subjected to displacement damage produced by 3.4 MeV Cu ions. D retention is subsequently explored by exposure of the W samples held at 383 K to a D 2 plasma ion fluence of 10 24 D +/m 2. Nuclear reaction analysis (NRA), utilizing the D( 3He,p) 4He nuclear reaction, is used to probe the D concentration in the nearmore » surface up to 6 μm. Thermal desorption spectroscopy (TDS) is used to measure outgassed HD and D 2 molecules to determine the bulk D concentration. Both NRA and TDS measure a significant reduction in D retention for samples damaged at elevated temperature. TDS quantitatively shows that the lowest energy trap remains largely unaffected while higher energy traps, induced by Cu ions, are annealed and approach intrinsic concentrations as the temperature during ion damage approaches 1243 K. Finally, analysis of TDS data yields an activation energy of (0.10 ± 0.02) eV for recovery of ion-damage induced traps at elevated temperature.« less

  16. Reduced deuterium retention in simultaneously damaged and annealed tungsten

    SciTech Connect

    Simmonds, M. J.; Wang, Y. Q.; Barton, J. L.

    Deuterium (D) retention in polycrystalline tungsten (W) with copper (Cu) ion damage concurrently produced at elevated surface temperature is investigated in this paper. An in situ heated stage held W samples at a controlled temperature up to 1243 K, which were subjected to displacement damage produced by 3.4 MeV Cu ions. D retention is subsequently explored by exposure of the W samples held at 383 K to a D 2 plasma ion fluence of 10 24 D +/m 2. Nuclear reaction analysis (NRA), utilizing the D( 3He,p) 4He nuclear reaction, is used to probe the D concentration in the nearmore » surface up to 6 μm. Thermal desorption spectroscopy (TDS) is used to measure outgassed HD and D 2 molecules to determine the bulk D concentration. Both NRA and TDS measure a significant reduction in D retention for samples damaged at elevated temperature. TDS quantitatively shows that the lowest energy trap remains largely unaffected while higher energy traps, induced by Cu ions, are annealed and approach intrinsic concentrations as the temperature during ion damage approaches 1243 K. Finally, analysis of TDS data yields an activation energy of (0.10 ± 0.02) eV for recovery of ion-damage induced traps at elevated temperature.« less

  17. VERA Core Simulator Methodology for PWR Cycle Depletion

    SciTech Connect

    Kochunas, Brendan; Collins, Benjamin S; Jabaay, Daniel

    2015-01-01

    This paper describes the methodology developed and implemented in MPACT for performing high-fidelity pressurized water reactor (PWR) multi-cycle core physics calculations. MPACT is being developed primarily for application within the Consortium for the Advanced Simulation of Light Water Reactors (CASL) as one of the main components of the VERA Core Simulator, the others being COBRA-TF and ORIGEN. The methods summarized in this paper include a methodology for performing resonance self-shielding and computing macroscopic cross sections, 2-D/1-D transport, nuclide depletion, thermal-hydraulic feedback, and other supporting methods. These methods represent a minimal set needed to simulate high-fidelity models of a realistic nuclearmore » reactor. Results demonstrating this are presented from the simulation of a realistic model of the first cycle of Watts Bar Unit 1. The simulation, which approximates the cycle operation, is observed to be within 50 ppm boron (ppmB) reactivity for all simulated points in the cycle and approximately 15 ppmB for a consistent statepoint. The verification and validation of the PWR cycle depletion capability in MPACT is the focus of two companion papers.« less

  18. Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley

    USGS Publications Warehouse

    Scanlon, Bridget R.; Faunt, Claudia C.; Longuevergne, Laurent; Reedy, Robert C.; Alley, William M.; McGuire, Virginia L.; McMahon, Peter B.

    2012-01-01

    Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ~50% of groundwater depletion in the United States since 1900. A newly developed High Plains recharge map shows that high recharge in the northern High Plains results in sustainable pumpage, whereas lower recharge in the central and southern High Plains has resulted in focused depletion of 330 km3 of fossil groundwater, mostly recharged during the past 13,000 y. Depletion is highly localized with about a third of depletion occurring in 4% of the High Plains land area. Extrapolation of the current depletion rate suggests that 35% of the southern High Plains will be unable to support irrigation within the next 30 y. Reducing irrigation withdrawals could extend the lifespan of the aquifer but would not result in sustainable management of this fossil groundwater. The Central Valley is a more dynamic, engineered system, with north/south diversions of surface water since the 1950s contributing to ~7× higher recharge. However, these diversions are regulated because of impacts on endangered species. A newly developed Central Valley Hydrologic Model shows that groundwater depletion since the 1960s, totaling 80 km3, occurs mostly in the south (Tulare Basin) and primarily during droughts. Increasing water storage through artificial recharge of excess surface water in aquifers by up to 3 km3 shows promise for coping with droughts and improving sustainability of groundwater resources in the Central Valley.

  19. Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley

    USGS Publications Warehouse

    Scanlon, Bridget R.; Faunt, Claudia; Longuevergne, Laurent; Reedy, Robert C.; Alley, William M.; McGuire, Virginia L.; McMahon, Peter B.

    2012-01-01

    Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ∼50% of groundwater depletion in the United States since 1900. A newly developed High Plains recharge map shows that high recharge in the northern High Plains results in sustainable pumpage, whereas lower recharge in the central and southern High Plains has resulted in focused depletion of 330 km3 of fossil groundwater, mostly recharged during the past 13,000 y. Depletion is highly localized with about a third of depletion occurring in 4% of the High Plains land area. Extrapolation of the current depletion rate suggests that 35% of the southern High Plains will be unable to support irrigation within the next 30 y. Reducing irrigation withdrawals could extend the lifespan of the aquifer but would not result in sustainable management of this fossil groundwater. The Central Valley is a more dynamic, engineered system, with north/south diversions of surface water since the 1950s contributing to ∼7× higher recharge. However, these diversions are regulated because of impacts on endangered species. A newly developed Central Valley Hydrologic Model shows that groundwater depletion since the 1960s, totaling 80 km3, occurs mostly in the south (Tulare Basin) and primarily during droughts. Increasing water storage through artificial recharge of excess surface water in aquifers by up to 3 km3 shows promise for coping with droughts and improving sustainability of groundwater resources in the Central Valley.

  20. Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley

    PubMed Central

    Scanlon, Bridget R.; Faunt, Claudia C.; Longuevergne, Laurent; Reedy, Robert C.; Alley, William M.; McGuire, Virginia L.; McMahon, Peter B.

    2012-01-01

    Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ∼50% of groundwater depletion in the United States since 1900. A newly developed High Plains recharge map shows that high recharge in the northern High Plains results in sustainable pumpage, whereas lower recharge in the central and southern High Plains has resulted in focused depletion of 330 km3 of fossil groundwater, mostly recharged during the past 13,000 y. Depletion is highly localized with about a third of depletion occurring in 4% of the High Plains land area. Extrapolation of the current depletion rate suggests that 35% of the southern High Plains will be unable to support irrigation within the next 30 y. Reducing irrigation withdrawals could extend the lifespan of the aquifer but would not result in sustainable management of this fossil groundwater. The Central Valley is a more dynamic, engineered system, with north/south diversions of surface water since the 1950s contributing to ∼7× higher recharge. However, these diversions are regulated because of impacts on endangered species. A newly developed Central Valley Hydrologic Model shows that groundwater depletion since the 1960s, totaling 80 km3, occurs mostly in the south (Tulare Basin) and primarily during droughts. Increasing water storage through artificial recharge of excess surface water in aquifers by up to 3 km3 shows promise for coping with droughts and improving sustainability of groundwater resources in the Central Valley. PMID:22645352

  1. Measurements of the nucleon structure function in the range 0.002 < x < 0.17 and 00.2 < Q2 < 8 GeV2 in deuterium, carbon and calcium

    NASA Astrophysics Data System (ADS)

    European Muon Collaboration; Arneodo, M.; Arvidson, A.; Aubert, J. J.; Badelek, B.; Beaufays, J.; Bee, C. P.; Benchouk, C.; Berghoff, G.; Bird, I. G.; Blum, D.; Böhm, E.; de Bouard, X.; Brasse, F. W.; Braun, H.; Broll, C.; Brown, S. C.; Brück, H.; Calén, H.; Chima, J. S.; Ciborowski, J.; Clifft, R.; Coignet, G.; Combley, F.; Coughlan, J.; d'Agostini, G.; Dahlgren, S.; Derado, I.; Dreyer, T.; Drees, J.; Düren, M.; Eckardt, V.; Edwards, A.; Edwards, M.; Ernst, T.; Eszes, G.; Favier, J.; Ferrero, M. I.; Figiel, J.; Flauger, W.; Foster, J.; Gabathuler, E.; Gajewski, J.; Gamet, R.; Geddes, N.; Grafström, P.; Gustafsson, L.; Haas, J.; Hagberg, E.; Hasert, F. J.; Hayman, P.; Heusse, P.; Jaffre, M.; Jacholkowska, A.; Janata, F.; Jancso, G.; Johnson, A. S.; Kabuss, E. M.; Kellner, G.; Krüger, A.; Krüger, J.; Kullander, S.; Landgraf, U.; Lanske, D.; Loken, J.; Long, K.; Maire, M.; Malecki, P.; Manz, A.; Maselli, S.; Mohr, W.; Montanet, F.; Montgomery, H. E.; Nagy, E.; Nassalski, J.; Norton, P. R.; Oakham, F. G.; Osborne, A. M.; Pascaud, C.; Pawlik, B.; Payre, P.; Peroni, C.; Peschel, H.; Pessard, H.; Pettingale, J.; Pietrzyk, B.; Poensgen, B.; Pötsch, M.; Renton, P.; Ribarics, P.; Rith, K.; Rondio, E.; Sandacz, A.; Scheer, M.; Schlagböhmer, A.; Schiemann, H.; Schmitz, N.; Schneegans, M.; Scholz, M.; Schouten, M.; Schröder, T.; Schultze, K.; Sloan, T.; Stier, H. E.; Studt, M.; Taylor, G. N.; Thenard, J. M.; Thompson, J. C.; de la Torre, A.; Toth, J.; Urban, L.; Urban, L.; Wallucks, W.; Whalley, M.; Wheeler, S.; Williams, W. S. C.; Wimpenny, S. J.; Windmolders, R.; Wolf, G.

    1990-03-01

    Small angle scattering of 280 GeV positive muons by deuterium, carbon and calcium has been measured at scattering angles down to 2 mrad. The nucleon structure function F2 extracted from deuterium does not show a significant x dependence in the measured range of Q2 and its Q2 dependence is linear in logQ2. For calcium, a depletion of F2 is observed at low x by 30% as compared with the values at x = 0.1 where F2(Ca) and F2 (D) are not significantly different. This depletion is attributed to shadowing. The carbon structure function exhibits a similar, but less pronounced, x dependence. Such behaviour is observed to be independent of Q2. The data are consistent with those obtained from other charged lepton experiments both at similar and higher values of x and Q2 and considerably extend the range of the measurements down to the low values of x to be measured in forthcoming experiments at HERA.

  2. [Acute tryptophan depletion in eating disorders].

    PubMed

    Díaz-Marsa, M; Lozano, C; Herranz, A S; Asensio-Vegas, M J; Martín, O; Revert, L; Saiz-Ruiz, J; Carrasco, J L

    2006-01-01

    This work describes the rational bases justifying the use of acute tryptophan depletion technique in eating disorders (ED) and the methods and design used in our studies. Tryptophan depletion technique has been described and used in previous studies safely and makes it possible to evaluate the brain serotonin activity. Therefore it is used in the investigation of hypotheses on serotonergic deficiency in eating disorders. Furthermore, and given the relationship of the dysfunctions of serotonin activity with impulsive symptoms, the technique may be useful in biological differentiation of different subtypes, that is restrictive and bulimic, of ED. 57 female patients with DSM-IV eating disorders and 20 female controls were investigated with the tryptophan depletion test. A tryptophan-free amino acid solution was administered orally after a two-day low tryptophan diet to patients and controls. Free plasma tryptophan was measured at two and five hours following administration of the drink. Eating and emotional responses were measured with specific scales for five hours following the depletion. A study of the basic characteristics of the personality and impulsivity traits was also done. Relationship of the response to the test with the different clinical subtypes and with the temperamental and impulsive characteristics of the patients was studied. The test was effective in considerably reducing plasma tryptophan in five hours from baseline levels (76%) in the global sample. The test was well tolerated and no severe adverse effects were reported. Two patients withdrew from the test due to gastric intolerance. The tryptophan depletion test could be of value to study involvement of serotonin deficits in the symptomatology and pathophysiology of eating disorders.

  3. Isothermal and non-isothermal infiltration and deuterium transport: a case study on undisturbed soil column from headwater catchment

    NASA Astrophysics Data System (ADS)

    Sobotkova, Martina; Snehota, Michal; Tesar, Miroslav

    2017-04-01

    Isothermal and non-isothermal infiltration experiments with tracer breakthrough were carried out in the laboratory on intact column of sandy loam soil taken from Roklan site (Sumava Mountains, Czech Republic). In the case of isothermal experiment, the temperature of infiltrating water was almost equal to the initial temperature of the sample. For the non-isothermal case the infiltration was performed using water approximately 10 °C colder than was the initial temperature of soil sample. The experiments were otherwise conducted under the same initial and boundary conditions. Pressure heads and temperatures in two depths (8.8 and 15.3 cm) inside the soil were monitored as well as the temperature of water entering and leaving the sample. Water drained freely through the perforated plate at the bottom of the sample by gravity and outflow was measured using tipping bucket flowmeter. Permeability of the sample calculated for steady state stages of the experiment showed that significant difference between water flow rates recorded during two experiment could not be justified only by temperature induced changes of water viscosity and density. Results of deuterium breakthrough were nearly identical for isothermal and non-isothermal conditions.

  4. Groundwater Depletion and Long term Food Security in India

    NASA Astrophysics Data System (ADS)

    Fishman, R.; Lall, U.; Modi, V.; Siegfried, T. U.; Narula, K. K.

    2009-12-01

    Unsustainable extraction of groundwater has led water tables to decline in many parts of India - the same parts that tend to produce most of the country’s food. Government policies like procurement and price guarantees for water intensive grains as well as subsidies on energy for pumping, originally intended to ensure national self-sufficiency in grain, are partly responsible for unsustainable groundwater extraction. The resulting groundwater depletion is associated with increasing burdens on state budgets and farmer incomes, and also risks irreversible damages to aquifers as a result of saline intrusion and other forms of pollution, processes that can undermine the prospects of long term food security. We discuss the policies and proposed solutions that might be able to maintain food security in the face of this impending crisis.

  5. Influence of salt intake, ANG II synthesis and SFO lesion on thirst and blood pressure during sodium depletion. Subfornical organ.

    PubMed

    Starbuck, E M; Fitts, D A

    1998-12-01

    Water intake was elevated in sodium-depleted rats during a daytime salt appetite test, but other rats drank a similar amount of water when saline was not available for drinking during the test. This water intake stimulated by sodium depletion was blocked by an inhibition of angiotensin (ANG) II synthesis with a high dose of captopril (100 mg/kg, sc). Captopril did not reduce water intake by causing hypotensive shock or uremia, because water and saline intakes were increased rather than decreased after a low dose of captopril (5 mg/kg) that also reduced blood pressure and elevated blood urea nitrogen. The water intake, but not salt appetite, induced by sodium depletion was greatly reduced by a lesion of the subfornical organ (SFO) in one-bottle tests, and this was not clearly related to any effects of the lesion on blood pressure. A physiological role for ANG II in water intake induced by sodium depletion has recently been disputed, but the simplest explanation for the data remains that elevated levels of circulating ANG II bind to receptors in the SFO to generate daytime water drinking during sodium depletion.

  6. Iron isotope composition of depleted MORB

    NASA Astrophysics Data System (ADS)

    Labidi, J.; Sio, C. K. I.; Shahar, A.

    2015-12-01

    In terrestrial basalts, iron isotope ratios are observed to weakly fractionate as a function of olivine and pyroxene crystallization. However, a ~0.1‰ difference between chondrites and MORB had been reported (Dauphas et al. 2009, Teng et al. 2013 and ref. therein). This observation could illustrate an isotope fractionation occurring during partial melting, as a function of the Fe valence in melt versus crystals. Here, we present high-precision Fe isotopic data measured by MC-ICP-MS on well-characterized samples from the Pacific-Antarctic Ridge (PAR, n=9) and from the Garrett Transform Fault (n=8). These samples allow exploring the Fe isotope fractionation between melt and magnetite, and the role of partial melting on Fe isotope fractionation. Our average δ56Fe value is +0.095±0.013‰ (95% confidence, n=17), indistinguishable from a previous estimate of +0.105±0.006‰ (95% confidence, n=43, see ref. 2). Our δ56Fe values correlate weakly with MgO contents, and correlate positively with K/Ti ratios. PAC1 DR10 shows the largest Ti and Fe depletion after titanomagnetite fractionation, with a δ56Fe value of +0.076±0.036‰. This is ~0.05‰ below other samples at a given MgO. This may illustrate a significant Fe isotope fractionation between the melt and titanomagnetite, in agreement with experimental determination (Shahar et al. 2008). GN09-02, the most incompatible-element depleted sample, has a δ56Fe value of 0.037±0.020‰. This is the lowest high-precision δ56Fe value recorded for a MORB worldwide. This basalt displays an incompatible-element depletion consistent with re-melting beneath the transform fault of mantle source that was depleted during a first melting event, beneath the ridge axis (Wendt et al. 1999). The Fe isotope observation could indicate that its mantle source underwent 56Fe depletion after a first melting event. It could alternatively indicate a lower Fe isotope fractionation during re-melting, if the source was depleted of its Fe3

  7. Estimation of stream depletion using values of capacitance

    NASA Astrophysics Data System (ADS)

    Baldenkov, Mikhail; Filimonova, Elena

    2014-05-01

    Compensation pumping is used to alleviate deficiencies in streamflow discharge during dry seasons. Short-term groundwater pumping can use aquifer storage instead of catchment-zone water until the drawdown reaches the edge of the stream. Stream-aquifer interactions are the key component of the hydrologic budgets and estimation of stream depletion has top-priority when evaluating the effectiveness of application of seasonal compensation pumping. Numerous analytical equations have been developed to assess the influence of groundwater pumping on nearby streams (C.V. Theis, R.E. Glover, C.G. Balmer, M.S. Hantush, C.T. Jenkins, B. Hunt, J. Bredehoeft, V.A. Zlotnik, E.L. Minkin, N.N. Lapshin, F.M. Bochever and other researchers). R.B. Wallace and Y. Darama obtained solution for cyclic conditions groundwater pumping. Numerical model approaches used in difficult hydrogeological conditions. It is offered to estimate stream depletion by seasonal pumping using values of capacitance (complex, dimensionless parameter of an aquifer system that defines the delayed effect on steamflow when there is groundwater pumping). Capacitance (C) is determined by the following equation: ( ) L* C = f( °---) , TS-Δt where S and T are the aquifer specific yield (or storage coefficient for a confined aquifer) and transmissivity, respectively; Δt is the pumping time inside one cycle, L* is the summarizing distance between the compensation well and stream edge; in some cases it can involve a function of the stream leakance and vertical leakance of the impermeable layer. Three typical hydraulic cases of compensation pumping were classified depending on their capacitance structure (i.e. the relationship between surface water and groundwater): (a) perfect hydraulic connection between the stream and aquifer; (b) imperfect hydraulic connection between the stream and aquifer; and (c) essentially imperfect hydraulic connection between the stream and the underlying confined aquifer. The form of

  8. Streamflow depletion by wells--Understanding and managing the effects of groundwater pumping on streamflow

    USGS Publications Warehouse

    Barlow, Paul M.; Leake, Stanley A.

    2012-11-02

    Groundwater is an important source of water for many human needs, including public supply, agriculture, and industry. With the development of any natural resource, however, adverse consequences may be associated with its use. One of the primary concerns related to the development of groundwater resources is the effect of groundwater pumping on streamflow. Groundwater and surface-water systems are connected, and groundwater discharge is often a substantial component of the total flow of a stream. Groundwater pumping reduces the amount of groundwater that flows to streams and, in some cases, can draw streamflow into the underlying groundwater system. Streamflow reductions (or depletions) caused by pumping have become an important water-resource management issue because of the negative impacts that reduced flows can have on aquatic ecosystems, the availability of surface water, and the quality and aesthetic value of streams and rivers. Scientific research over the past seven decades has made important contributions to the basic understanding of the processes and factors that affect streamflow depletion by wells. Moreover, advances in methods for simulating groundwater systems with computer models provide powerful tools for estimating the rates, locations, and timing of streamflow depletion in response to groundwater pumping and for evaluating alternative approaches for managing streamflow depletion. The primary objective of this report is to summarize these scientific insights and to describe the various field methods and modeling approaches that can be used to understand and manage streamflow depletion. A secondary objective is to highlight several misconceptions concerning streamflow depletion and to explain why these misconceptions are incorrect.

  9. Influence of traps on the deuterium behaviour in the low activation martensitic steels F82H and Batman

    NASA Astrophysics Data System (ADS)

    Serra, E.; Perujo, A.; Benamati, G.

    1997-06-01

    A time dependent permeation method is used to measure the permeability, diffusivity and solubility of deuterium in the low activation martensitic steels F82H and Batman. The measurements cover the temperature range from 373 to 743 K which includes the onset of deuterium trapping effects on diffusivity and solubility. The results are interpreted using a trapping model. The number of trap sites and their average energies for deuterium in F82H and Batman steels are determined.

  10. Palladium-catalyzed Br/D exchange of arenes: Selective deuterium incorporation with versatile functional group tolerance and high efficiency

    DOE PAGES

    Zhang, Honghai -Hai; Bonnesen, Peter V.; Hong, Kunlun

    2015-07-13

    There is a facile method for introducing one or more deuterium atoms onto an aromatic nucleus via Br/D exchange with high functional group tolerance and high incorporation efficiency is disclosed. Deuterium-labeled aryl chlorides and aryl borates which could be used as substrates in cross-coupling reactions to construct more complicated deuterium-labeled compounds can also be synthesized by this method.

  11. Depletion of metronidazole in brook trout (Salvelinus fontinalis).

    PubMed

    Watson, Lynn; MacNeil, James D; Potter, Ross; Hellou, Jocelyne

    2015-01-01

    Metronidazole (MNZ), which is effective in the treatment of intestinal infections in fish, is also a suspected carcinogen and has been banned in numerous jurisdictions for use in any food-producing animal, including fish. Few reports have been published on the depletion of MNZ in fish. A depletion study was therefore undertaken using MNZ in feed provided to trout under controlled conditions. The water was maintained at 17.5 ± 0.9°C throughout the medication and depletion periods in the study. Following a 20-day acclimatisation period in the holding tanks, the trout (approximately 150-200 g bodyweight at the start of the study) were subjected to two separate medication and withdrawal periods: (A) 5 day medication/5 day withdrawal and (B) 5 day medication/16 day withdrawal. This simulated a potential multiple dosing in an aquaculture setting. In both medication periods, the trout were dosed with medicated feed containing 3 g MNZ kg(-1) fish. Fish were sacrificed in accordance with accepted animal care protocols and tissue samples were analysed by UPLC-MS/MS. Analyte concentrations in trout muscle ranged from a high of 27,000 ± 10,000 ng g(-1) for MNZ and 830 ± 570 ng g(-1) for MNZ-OH on day 1 of withdrawal period A to a low of 1.8 ± 2.3 ng g(-1) for MNZ and < 0.4 ng g(-1) for MNZ-OH on day 16 of withdrawal period B. The results demonstrate that when using the UPLC-MS/MS method, residues of MNZ may be detected in fish treated with MNZ after 16 days of withdrawal.

  12. From Deuterium to Free Neutrons - Recent Experimental Results

    NASA Astrophysics Data System (ADS)

    Kuhn, Sebastian

    2009-05-01

    Lepton scattering has long been used to gather data on the internal structure of both protons and neutrons. Assuming isospin symmetry, these data can be used to pin down the contributions of both u and d quarks to the spatial and momentum-spin structure of the nucleon and its excitations. In this context, information on the neutron is crucial and is typically obtained from experiments on few-body nuclear targets (predominantly ^3He and deuterium). However, the need to account for binding effects complicates the interpretation of these experiments. On the other hand, detailed studies of the reaction mechanism can yield important new information on the structure of few-body nuclei and the interplay of nuclear and quark degrees of freedom. Recent theoretical and experimental advances have allowed us to make significant progress on both fronts -- a cleaner extraction of neutron properties from nuclear data and a better understanding of nuclear modifications of the bound neutron structure. I will concentrate on recent results on the deuteron. I will present a new extraction of neutron spin structure functions in the resonance and large-x region (from the EG1 experiment with CLAS at Jefferson Lab). The same data can also be used for a detailed comparison with modern calculations of quasi-elastic spin-dependent scattering on the deuteron. A second experimental program with CLAS uses the technique of ``spectator tagging'' to extract the unpolarized structure functions of the neutron with minimal uncertainties from nuclear effects. By mapping out the dependence of the cross section on the ``spectator'' momentum, we can learn about final state interactions between the struck nucleon and the spectator, as well as modifications of the neutron structure due to nuclear binding. I will present preliminary results from the ``BoNuS'' experiment which pushed the detection limit of the spectator proton down to momenta of 70 MeV/c, where nuclear corrections should become small.

  13. Deuterium permeation behaviors in tungsten implanted with nitrogen

    NASA Astrophysics Data System (ADS)

    Liang, Chuan-hui; Wang, Dongping; Jin, Wei; Lou, Yuanfu; Wang, Wei; Ye, Xiaoqiu; Chen, Chang-an; Liu, Kezhao; Xu, Haiyan; Wang, Xiaoying; Kleyn, Aart W.

    2018-07-01

    Surface modification of tungsten due to the cooling species nitrogen seeded in the divertor region, i.e., by nitrogen ion implantation or re-deposition, is considered to affect the permeation behavior of H isotopes. This work focuses on the effect of nitrogen ion implantation into tungsten (W-N) on the deuterium gas-driven permeation behavior. For comparison, both permeation in tungsten implanted with W ion (W-W) and without implantation (pristine W) are studied. These three samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photo-electron spectroscopy (XPS). The SEM results revealed that the W-W sample has various voids on the surface, and the W-N sample has a rough surface with pretty fine microstructures. These are different from the pristine W sample with a smooth and compact surface. The XRD patterns show the disappearance of crystallinity on both W-W and W-N sample surfaces. It indicates that the ion implantation process results in an almost complete conversion from crystalline to amorphous in the sample surfaces. The sputter-depth profiling XPS spectra show that the implanted nitrogen prefers to form a 140 nm thick tungsten nitride layer. In permeation experiments, it was found that the D permeability is temperature dependent. Interestingly, the W-N sample presented a lower D permeability than the W-W sample, but higher than the pristine W sample. Such behavior implies that tungsten nitride acts as a permeation barrier, while defects created by ions implantation can promote permeability. The possible permeation mechanism correlated with sample surface composition and microstructure is consequently discussed in this work.

  14. A new, precise measurement of the primordial abundance of deuterium

    NASA Astrophysics Data System (ADS)

    Pettini, Max; Cooke, Ryan

    2012-10-01

    The metal-poor (Z ≃ 1/100 Z⊙) damped Lyman α system (DLA) at redshift zabs = 3.049 84 in the zem ≃ 3.030 QSO SDSS J1419+0829 has near-ideal properties for an accurate determination of the primordial abundance of deuterium (D/H)p. We have analysed a high-quality spectrum of this object with software specifically designed to deduce the best-fitting value of D/H and to assess comprehensively the random and systematic errors affecting this determination. We find (D/H)DLA = (2.535 ± 0.05) × 10-5, which in turn implies Ωb, 0h2 = 0.0223 ± 0.0009, in very good agreement with Ωb, 0h2(CMB) = 0.0222 ± 0.0004 deduced from the angular power spectrum of the cosmic microwave background (CMB). If the value in this DLA is indeed the true (D/H)p produced by big bang nucleosynthesis (BBN), there may be no need to invoke non-standard physics nor early astration of D to bring together Ωb, 0 h2(BBN) and Ωb, 0 h2(CMB). The scatter between most of the reported values of (D/H)p in the literature may be due largely to unaccounted systematic errors and biases. Further progress in this area will require a homogeneous set of data comparable to those reported here and analysed in a self-consistent manner. Such an endeavour, while observationally demanding, has the potential of improving our understanding of BBN physics, including the relevant nuclear reactions, and the subsequent processing of light nuclides through stars. Based on observations collected at the European Organisation for Astronomical Research in the Southern hemisphere, Chile [Very Large Telescope programme ID 085.A-0109(A)].

  15. Nuclide Depletion Capabilities in the Shift Monte Carlo Code

    DOE PAGES

    Davidson, Gregory G.; Pandya, Tara M.; Johnson, Seth R.; ...

    2017-12-21

    A new depletion capability has been developed in the Exnihilo radiation transport code suite. This capability enables massively parallel domain-decomposed coupling between the Shift continuous-energy Monte Carlo solver and the nuclide depletion solvers in ORIGEN to perform high-performance Monte Carlo depletion calculations. This paper describes this new depletion capability and discusses its various features, including a multi-level parallel decomposition, high-order transport-depletion coupling, and energy-integrated power renormalization. Several test problems are presented to validate the new capability against other Monte Carlo depletion codes, and the parallel performance of the new capability is analyzed.

  16. Endoplasmic-Reticulum Calcium Depletion and Disease

    PubMed Central

    Mekahli, Djalila; Bultynck, Geert; Parys, Jan B.; De Smedt, Humbert; Missiaen, Ludwig

    2011-01-01

    The endoplasmic reticulum (ER) as an intracellular Ca2+ store not only sets up cytosolic Ca2+ signals, but, among other functions, also assembles and folds newly synthesized proteins. Alterations in ER homeostasis, including severe Ca2+ depletion, are an upstream event in the pathophysiology of many diseases. On the one hand, insufficient release of activator Ca2+ may no longer sustain essential cell functions. On the other hand, loss of luminal Ca2+ causes ER stress and activates an unfolded protein response, which, depending on the duration and severity of the stress, can reestablish normal ER function or lead to cell death. We will review these various diseases by mainly focusing on the mechanisms that cause ER Ca2+ depletion. PMID:21441595

  17. Depletion zones and crystallography on pinched spheres

    NASA Astrophysics Data System (ADS)

    Chen, Jingyuan; Xing, Xiangjun; Yao, Zhenwei

    2018-03-01

    Understanding the interplay between ordered structures and substrate curvature is an interesting problem with versatile applications, including functionalization of charged supramolecular surfaces and modern microfluidic technologies. In this work, we investigate the two-dimensional packing structures of charged particles confined on a pinched sphere. By continuously pinching the sphere, we observe cleavage of elongated scars into pleats, proliferation of disclinations, and subsequently, emergence of a depletion zone at the negatively curved waist that is completely void of particles. We systematically study the geometrics and energetics of the depletion zone, and reveal its physical origin as a finite size effect, due to the interplay between Coulomb repulsion and concave geometry of the pinched sphere. These results further our understanding of crystallography on curved surfaces, and have implications in design and manipulation of charged, deformable interfaces in various applications.

  18. Review of analytical models to stream depletion induced by pumping: Guide to model selection

    NASA Astrophysics Data System (ADS)

    Huang, Ching-Sheng; Yang, Tao; Yeh, Hund-Der

    2018-06-01

    Stream depletion due to groundwater extraction by wells may cause impact on aquatic ecosystem in streams, conflict over water rights, and contamination of water from irrigation wells near polluted streams. A variety of studies have been devoted to addressing the issue of stream depletion, but a fundamental framework for analytical modeling developed from aquifer viewpoint has not yet been found. This review shows key differences in existing models regarding the stream depletion problem and provides some guidelines for choosing a proper analytical model in solving the problem of concern. We introduce commonly used models composed of flow equations, boundary conditions, well representations and stream treatments for confined, unconfined, and leaky aquifers. They are briefly evaluated and classified according to six categories of aquifer type, flow dimension, aquifer domain, stream representation, stream channel geometry, and well type. Finally, we recommend promising analytical approaches that can solve stream depletion problem in reality with aquifer heterogeneity and irregular geometry of stream channel. Several unsolved stream depletion problems are also recommended.

  19. The ultimate disposition of depleted uranium

    SciTech Connect

    Not Available

    1990-12-01

    Significant amounts of the depleted uranium (DU) created by past uranium enrichment activities have been sold, disposed of commercially, or utilized by defense programs. In recent years, however, the demand for DU has become quite small compared to quantities available, and within the US Department of Energy (DOE) there is concern for any risks and/or cost liabilities that might be associated with the ever-growing inventory of this material. As a result, Martin Marietta Energy Systems, Inc. (Energy Systems), was asked to review options and to develop a comprehensive plan for inventory management and the ultimate disposition of DU accumulated atmore » the gaseous diffusion plants (GDPs). An Energy Systems task team, under the chairmanship of T. R. Lemons, was formed in late 1989 to provide advice and guidance for this task. This report reviews options and recommends actions and objectives in the management of working inventories of partially depleted feed (PDF) materials and for the ultimate disposition of fully depleted uranium (FDU). Actions that should be considered are as follows. (1) Inspect UF{sub 6} cylinders on a semiannual basis. (2) Upgrade cylinder maintenance and storage yards. (3) Convert FDU to U{sub 3}O{sub 8} for long-term storage or disposal. This will include provisions for partial recovery of costs to offset those associated with DU inventory management and the ultimate disposal of FDU. Another recommendation is to drop the term tails'' in favor of depleted uranium'' or DU'' because the tails'' label implies that it is waste.'' 13 refs.« less

  20. Carbon sequestration in depleted oil shale deposits

    DOEpatents

    Burnham, Alan K; Carroll, Susan A

    2014-12-02

    A method and apparatus are described for sequestering carbon dioxide underground by mineralizing the carbon dioxide with coinjected fluids and minerals remaining from the extraction shale oil. In one embodiment, the oil shale of an illite-rich oil shale is heated to pyrolyze the shale underground, and carbon dioxide is provided to the remaining depleted oil shale while at an elevated temperature. Conditions are sufficient to mineralize the carbon dioxide.

  1. Estimation of groundwater recharge via deuterium labelling in the semi-arid Cuvelai-Etosha Basin, Namibia.

    PubMed

    Beyer, Matthias; Gaj, Marcel; Hamutoko, Josefina Tulimeveva; Koeniger, Paul; Wanke, Heike; Himmelsbach, Thomas

    2015-01-01

    The stable water isotope deuterium ((2)H) was applied as an artificial tracer ((2)H2O) in order to estimate groundwater recharge through the unsaturated zone and describe soil water movement in a semi-arid region of northern central Namibia. A particular focus of this study was to assess the spatiotemporal persistence of the tracer when applied in the field on a small scale under extreme climatic conditions and to propose a method to obtain estimates of recharge in data-scarce regions. At two natural sites that differ in vegetation cover, soil and geology, 500 ml of a 70% (2)H2O solution was irrigated onto water saturated plots. The displacement of the (2)H peak was analyzed 1 and 10 days after an artificial rain event of 20 mm as well as after the rainy season. Results show that it is possible to apply the peak displacement method for the estimation of groundwater recharge rates in semi-arid environments via deuterium labelling. Potential recharge for the rainy season 2013/2014 was calculated as 45 mm a(-1) at 5.6 m depth and 40 mm a(-1) at 0.9 m depth at the two studied sites, respectively. Under saturated conditions, the artificial rain events moved 2.1 and 0.5 m downwards, respectively. The tracer at the deep sand site (site 1) was found after the rainy season at 5.6 m depth, corresponding to a displacement of 3.2 m. This equals in an average travel velocity of 2.8 cm d(-1) during the rainy season at the first site. At the second location, the tracer peak was discovered at 0.9 m depth; displacement was found to be only 0.4 m equalling an average movement of 0.2 cm d(-1) through the unsaturated zone due to an underlying calcrete formation. Tracer recovery after one rainy season was found to be as low as 3.6% at site 1 and 1.9% at site 2. With an in situ measuring technique, a three-dimensional distribution of (2)H after the rainy season could be measured and visualized. This study comprises the first application of the peak displacement method using a

  2. Understanding the haling power depletion (HPD) method

    SciTech Connect

    Levine, S.; Blyth, T.; Ivanov, K.

    2012-07-01

    The Pennsylvania State Univ. (PSU) is using the university version of the Studsvik Scandpower Code System (CMS) for research and education purposes. Preparations have been made to incorporate the CMS into the PSU Nuclear Engineering graduate class 'Nuclear Fuel Management' course. The information presented in this paper was developed during the preparation of the material for the course. The Haling Power Depletion (HPD) was presented in the course for the first time. The HPD method has been criticized as not valid by many in the field even though it has been successfully applied at PSU for the past 20 years.more » It was noticed that the radial power distribution (RPD) for low leakage cores during depletion remained similar to that of the HPD during most of the cycle. Thus, the Haling Power Depletion (HPD) may be used conveniently mainly for low leakage cores. Studies were then made to better understand the HPD and the results are presented in this paper. Many different core configurations can be computed quickly with the HPD without using Burnable Poisons (BP) to produce several excellent low leakage core configurations that are viable for power production. Once the HPD core configuration is chosen for further analysis, techniques are available for establishing the BP design to prevent violating any of the safety constraints in such HPD calculated cores. In summary, in this paper it has been shown that the HPD method can be used for guiding the design for the low leakage core. (authors)« less

  3. Renal Cortical Pyruvate Depletion during AKI

    PubMed Central

    Johnson, Ali C.M.; Becker, Kirsten

    2014-01-01

    Pyruvate is a key intermediary in energy metabolism and can exert antioxidant and anti-inflammatory effects. However, the fate of pyruvate during AKI remains unknown. Here, we assessed renal cortical pyruvate and its major determinants (glycolysis, gluconeogenesis, pyruvate dehydrogenase [PDH], and H2O2 levels) in mice subjected to unilateral ischemia (15–60 minutes; 0–18 hours of vascular reflow) or glycerol-induced ARF. The fate of postischemic lactate, which can be converted back to pyruvate by lactate dehydrogenase, was also addressed. Ischemia and glycerol each induced persistent pyruvate depletion. During ischemia, decreasing pyruvate levels correlated with increasing lactate levels. During early reperfusion, pyruvate levels remained depressed, but lactate levels fell below control levels, likely as a result of rapid renal lactate efflux. During late reperfusion and glycerol-induced AKI, pyruvate depletion corresponded with increased gluconeogenesis (pyruvate consumption). This finding was underscored by observations that pyruvate injection increased renal cortical glucose content in AKI but not normal kidneys. AKI decreased PDH levels, potentially limiting pyruvate to acetyl CoA conversion. Notably, pyruvate therapy mitigated the severity of AKI. This renoprotection corresponded with increases in cytoprotective heme oxygenase 1 and IL-10 mRNAs, selective reductions in proinflammatory mRNAs (e.g., MCP-1 and TNF-α), and improved tissue ATP levels. Paradoxically, pyruvate increased cortical H2O2 levels. We conclude that AKI induces a profound and persistent depletion of renal cortical pyruvate, which may induce additional injury. PMID:24385590

  4. Neutral depletion and the helicon density limit

    SciTech Connect

    Magee, R. M.; Galante, M. E.; Carr, J. Jr.

    2013-12-15

    It is straightforward to create fully ionized plasmas with modest rf power in a helicon. It is difficult, however, to create plasmas with density >10{sup 20} m{sup −3}, because neutral depletion leads to a lack of fuel. In order to address this density limit, we present fast (1 MHz), time-resolved measurements of the neutral density at and downstream from the rf antenna in krypton helicon plasmas. At the start of the discharge, the neutral density underneath the antenna is reduced to 1% of its initial value in 15 μs. The ionization rate inferred from these data implies that the electronmore » temperature near the antenna is much higher than the electron temperature measured downstream. Neutral density measurements made downstream from the antenna show much slower depletion, requiring 14 ms to decrease by a factor of 1/e. Furthermore, the downstream depletion appears to be due to neutral pumping rather than ionization.« less

  5. OZONE DEPLETION AND THE AIR-SEA EXCHANGE OF GREENHOUSE AND CHEMICALLY REACTIVE TRACE GASES

    EPA Science Inventory

    One of the most important aspects of global change is that of stratospheric ozone depletion and the resulting increase in UV radiation reaching the surface of the Earth. Some 70% of the Earth surface is covered by water containing an extremely complicated milieu of organic and in...

  6. The application of depletion curves for parameterization of subgrid variability of snow

    Treesearch

    C. H. Luce; D. G. Tarboton

    2004-01-01

    Parameterization of subgrid-scale variability in snow accumulation and melt is important for improvements in distributed snowmelt modelling. We have taken the approach of using depletion curves that relate fractional snowcovered area to element-average snow water equivalent to parameterize the effect of snowpack heterogeneity within a physically based mass and energy...

  7. The Effect of Ion Energy and Substrate Temperature on Deuterium Trapping in Tungsten

    NASA Astrophysics Data System (ADS)

    Roszell, John Patrick Town

    Tungsten is a candidate plasma facing material for next generation magnetic fusion devices such as ITER and there are major operational and safety issues associated with hydrogen (tritium) retention in plasma facing components. An ion gun was used to simulate plasma-material interactions under various conditions in order to study hydrogen retention characteristics of tungsten thus enabling better predictions of hydrogen retention in ITER. Thermal Desorption Spectroscopy (TDS) was used to measure deuterium retention from ion irradiation while modelling of TDS spectra with the Tritium Migration Analysis Program (TMAP) was used to provide information about the trapping mechanisms involved in deuterium retention in tungsten. X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) were used to determine the depth resolved composition of specimens used for irradiation experiments. Carbon and oxygen atoms will be among the most common contaminants within ITER. C and O contamination in polycrystalline tungsten (PCW) specimens even at low levels (˜0.1%) was shown to reduce deuterium retention by preventing diffusion of deuterium into the bulk of the specimen. This diffusion barrier was also responsible for the inhibition of blister formation during irradiations at 500 K. These observations may provide possible mitigation techniques for problems associated with tritium retention and mechanical damage to plasma facing components caused by hydrogen implantation. Deuterium trapping in PCW and single crystal tungsten (SCW) was studied as a function of ion energy and substrate temperature. Deuterium retention was shown to decrease with decreasing ion energy below 100 eV/D+. Irradiation of tungsten specimens with 10 eV/D+ ions was shown to retain up to an order of magnitude less deuterium than irradiation with 500 eV/D+ ions. Furthermore, the retention mechanism for deuterium was shown to be consistent across the entire energy range studied (10-500 e

  8. Variable-temperature Fourier transform near-infrared imaging spectroscopy of the deuterium/hydrogen exchange in liquid D₂O.

    PubMed

    Unger, Miriam; Ozaki, Yukihiro; Siesler, Heinz W

    2014-01-01

    In the present publication, the deuterium/hydrogen (D/H) exchange of liquid D2O exposed to water vapor of the surrounding atmosphere has been studied by variable-temperature Fourier transform near-infrared (FT-NIR) imaging spectroscopy. Apart from the visualization of the exchange process in the time-resolved FT-NIR images, kinetic parameters and the activation energy for this D/H exchange reaction have been derived from the Arrhenius plot of the variable-temperature spectroscopic data.

  9. Hydraulic redistribution under moderate drought among English oak, European beech and Norway spruce determined by deuterium isotope labeling in a split-root experiment.

    PubMed

    Hafner, Benjamin D; Tomasella, Martina; Häberle, Karl-Heinz; Goebel, Marc; Matyssek, Rainer; Grams, Thorsten E E

    2017-07-01

    Hydraulic redistribution (HR) of soil water through plant roots is a crucial phenomenon improving the water balance of plants and ecosystems. It is mostly described under severe drought, and not yet studied under moderate drought. We tested the potential of HR under moderate drought, hypothesizing that (H1) tree species redistribute soil water in their roots even under moderate drought and that (H2) neighboring plants are supported with water provided by redistributing plants. Trees were planted in split-root systems with one individual (i.e., split-root plant, SRP) having its roots divided between two pots with one additional tree each. Species were 2- to  4-year-old English oak (Quercus robur L.), European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst). A gradient in soil water potential (ψsoil) was established between the two pots (-0.55 ± 0.02 MPa and -0.29 ± 0.03 MPa), and HR was observed by labeling with deuterium-enriched water. Irrespective of species identity, 93% of the SRPs redistributed deuterium enriched water from the moist to the drier side, supporting H1. Eighty-eight percent of the plants in the drier pots were deuterium enriched in their roots, with 61 ± 6% of the root water originating from SRP roots. Differences in HR among species were related to their root anatomy with diffuse-porous xylem structure in both beech and-opposing the stem structure-oak roots. In spruce, we found exclusively tracheids. We conclude that water can be redistributed within roots of different tree species along a moderate ψsoil gradient, accentuating HR as an important water source for drought-stressed plants, with potential implications for ecohydrological and plant physiological sciences. It remains to be shown to what extent HR occurs under field conditions in Central Europe. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Technical note: Evaluating nuclear magnetic resonance spectroscopy for determining body composition in Holstein dairy calves using deuterium oxide dilution methods.

    PubMed

    Chapman, C E; Wilkinson, P Stone; Murphy, M R; Erickson, P S

    2017-04-01

    Deuterium oxide (D 2 O) dilution methods have been used to assess body composition in live animals. Estimated body water content can be used to predict body fat and protein, and thus, the amount of energy reserves. It is an alternative method to direct chemical analysis and considered a noninvasive technique that is economical and repeatable. Deuterium oxide use is considered easy, safe, and accurate; however, the traditional methods of analyzing D 2 O are expensive, tedious, and time consuming. The objective of this study was to evaluate the potential for using nuclear magnetic resonance spectroscopy (NMR) to determine body composition in Holstein dairy heifers. Nuclear magnetic resonance is less expensive and requires minutes to calculate the percentage of D 2 O in the blood. This study used 24 newborn dairy heifer calves blocked by birth and randomly assigned to 1 of 3 treatments: (1) 446 g dry matter (DM) of a conventional milk replacer (MR) [CON; 20% crude protein (CP), 20% fat], (2) 669 g DM of a moderately high protein MR (MOD; 26% CP, 18% fat), or (3) 892 g DM of a moderately high protein MR (aggressive, AGG; 26% CP, 18% fat). All calves had free-choice access to starter and water. Both MR and starter were medicated with decoquinate. During weaning (d 43 to 49), the morning MR feeding ceased. On d 50, all MR feedings ended but starter and water intakes were continuously recorded until d 56. When calves were 50 d of age, a baseline blood sample was taken followed by injection of 300 mg of D 2 O/kg of body weight in sterile physiological saline (0.9%). The syringes containing the D 2 O in physiological saline were weighed before and after administration to record the actual dose of D 2 O injected gravimetrically. After injection, the D 2 O was allowed to equilibrate with body water for 1 h. Six blood samples were taken over 6 d (1/d) at 1630 h to estimate the dilution of the tracer. The plasma was aspirated and stored at -20°C until further D 2 O analysis

  11. In-vivo NMR studies of deuterium-labeled photosensitizers in mice tumor model

    NASA Astrophysics Data System (ADS)

    Ramaprasad, Subbaraya; Liu, Y. H.; Pandey, R. K.; Shiau, Fuu-Yau; Smith, Kevin M.

    1993-06-01

    Photodynamic therapy (PDT) has emerged as a promising modality for the treatment of cancer. We are using newly synthesized and chemically defined and characterized porphyrin photosensitizers that are specifically labeled with deuterium to perform in vivo NMR studies in a murine tumor model. In vivo magnetic resonance offers the potential for repetitive, safe, noninvasive evaluation of photosensitizers, tumor metabolism, and the effect of PDT on the tumor metabolism. In an effort to monitor noninvasively the photosensitizers in an in vivo tumor model, we are synthesizing several deuterium labeled photosensitizers which absorb red light at or above 630 nm. Development of methods to test these photosensitizers directly in humans is not feasible at this time, since these photosensitizers are new and we do not yet understand the side effects. In addition, we do not understand the potential benefits compared with Photofrin II, the widely used photosensitizer. To perform our in vivo deuterium NMR studies on mouse foot tumors, we have constructed a solenoid coil which operates at 30.7 MHz for the deuterium nucleus. We have been able to detect the deuterium labeled photosensitizer in the tumor after a direct intra-tumor injection. The use of 31P NMR to predict the possible outcome of PDT in these tumors is also discussed.

  12. Deuterium depth profile quantification in a ASDEX Upgrade divertor tile using secondary ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Ghezzi, F.; Caniello, R.; Giubertoni, D.; Bersani, M.; Hakola, A.; Mayer, M.; Rohde, V.; Anderle, M.; ASDEX Upgrade Team

    2014-10-01

    We present the results of a study where secondary ion mass spectrometry (SIMS) has been used to obtain depth profiles of deuterium concentration on plasma facing components of the first wall of the ASDEX Upgrade tokamak. The method uses primary and secondary standards to quantify the amount of deuterium retained. Samples of bulk graphite coated with tungsten or tantalum-doped tungsten are independently profiled with three different SIMS instruments. Their deuterium concentration profiles are compared showing good agreement. In order to assess the validity of the method, the integrated deuterium concentrations in the coatings given by one of the SIMS devices is compared with nuclear reaction analysis (NRA) data. Although in the case of tungsten the agreement between NRA and SIMS is satisfactory, for tantalum-doped tungsten samples the discrepancy is significant because of matrix effect induced by tantalum and differently eroded surface (W + Ta always exposed to plasma, W largely shadowed). A further comparison where the SIMS deuterium concentration is obtained by calibrating the measurements against NRA values is also presented. For the tungsten samples, where no Ta induced matrix effects are present, the two methods are almost equivalent.The results presented show the potential of the method provided that the standards used for the calibration reproduce faithfully the matrix nature of the samples.

  13. Site occupancy of interstitial deuterium atoms in face-centred cubic iron

    PubMed Central

    Machida, Akihiko; Saitoh, Hiroyuki; Sugimoto, Hidehiko; Hattori, Takanori; Sano-Furukawa, Asami; Endo, Naruki; Katayama, Yoshinori; Iizuka, Riko; Sato, Toyoto; Matsuo, Motoaki; Orimo, Shin-ichi; Aoki, Katsutoshi

    2014-01-01

    Hydrogen composition and occupation state provide basic information for understanding various properties of the metal–hydrogen system, ranging from microscopic properties such as hydrogen diffusion to macroscopic properties such as phase stability. Here the deuterization process of face-centred cubic Fe to form solid-solution face-centred cubic FeDx is investigated using in situ neutron diffraction at high temperature and pressure. In a completely deuterized specimen at 988 K and 6.3 GPa, deuterium atoms occupy octahedral and tetrahedral interstitial sites with an occupancy of 0.532(9) and 0.056(5), respectively, giving a deuterium composition x of 0.64(1). During deuterization, the metal lattice expands approximately linearly with deuterium composition at a rate of 2.21 Å3 per deuterium atom. The minor occupation of the tetrahedral site is thermally driven by the intersite movement of deuterium atoms along the ‹111› direction in the face-centred cubic metal lattice. PMID:25256789

  14. Filtration System for Removal of Depleted Uranium from Water.

    DTIC Science & Technology

    1988-02-01

    PVC, 3-Way 65 1 1" Pressure Control Valve, Posacon #677, PVC Body, EPDM Diaphragm, Threaded Union Ends Valves with Actuators 29 2 1" PVC 3-Way Multi...Gaskets/Clamps 14 24 1/2" x 2 1/4" LG. Machine Bolts 15 32 1,2" Hex Nuts 16 64 1/2" Washer 17 8 1 1𔃼" Full Face Black Rubber Gasket 36 8 5/8" x 3" LG...Machine Bolts 37 8 5/8" Hex Nuts 38 16 5/8" Washers 39 6 3" Full Face Black Rubber Gasket 45 8 1/2" x 2 1/4" Machine Bolts 78 6 1 1/2" K40 Gasket 79 2 2

  15. Assessing local planning to control groundwater depletion: California as a microcosm of global issues

    NASA Astrophysics Data System (ADS)

    Nelson, Rebecca L.

    2012-01-01

    Groundwater pumping has caused excessive groundwater depletion around the world, yet regulating pumping remains a profound challenge. California uses more groundwater than any other U.S. state, and serves as a microcosm of the adverse effects of pumping felt worldwide—land subsidence, impaired water quality, and damaged ecosystems, all against the looming threat of climate change. The state largely entrusts the control of depletion to the local level. This study uses internationally accepted water resources planning theories systematically to investigate three key aspects of controlling groundwater depletion in California, with an emphasis on local-level action: (a) making decisions and engaging stakeholders; (b) monitoring groundwater; and (c) using mandatory, fee-based and voluntary approaches to control groundwater depletion (e.g., pumping restrictions, pumping fees, and education about water conservation, respectively). The methodology used is the social science-derived technique of content analysis, which involves using a coding scheme to record these three elements in local rules and plans, and State legislation, then analyzing patterns and trends. The study finds that Californian local groundwater managers rarely use, or plan to use, mandatory and fee-based measures to control groundwater depletion. Most use only voluntary approaches or infrastructure to attempt to reduce depletion, regardless of whether they have more severe groundwater problems, or problems which are more likely to have irreversible adverse effects. The study suggests legal reforms to the local groundwater planning system, drawing upon its empirical findings. Considering the content of these recommendations may also benefit other jurisdictions that use a local groundwater management planning paradigm.

  16. Potential and timescales for oxygen depletion in coastal upwelling systems: A box-model analysis

    NASA Astrophysics Data System (ADS)

    Harrison, C. S.; Hales, B.; Siedlecki, S.; Samelson, R. M.

    2016-05-01

    A simple box model is used to examine oxygen depletion in an idealized ocean-margin upwelling system. Near-bottom oxygen depletion is controlled by a competition between flushing with oxygenated offshore source waters and respiration of particulate organic matter produced near the surface and retained near the bottom. Upwelling-supplied nutrients are consumed in the surface box, and some surface particles sink to the bottom where they respire, consuming oxygen. Steady states characterize the potential for hypoxic near-bottom oxygen depletion; this potential is greatest for faster sinking rates, and largely independent of production timescales except in that faster production allows faster sinking. Timescales for oxygen depletion depend on upwelling and productivity differently, however, as oxygen depletion can only be reached in meaningfully short times when productivity is rapid. Hypoxia thus requires fast production, to capture upwelled nutrients, and fast sinking, to deliver the respiration potential to model bottom waters. Combining timescales allows generalizations about tendencies toward hypoxia. If timescales of sinking are comparable to or smaller than the sum of those for respiration and flushing, the steady state will generally be hypoxic, and results indicate optimal timescales and conditions exist to generate hypoxia. For example, the timescale for approach to hypoxia lengthens with stronger upwelling, since surface particle and nutrient are shunted off-shelf, in turn reducing subsurface respiration and oxygen depletion. This suggests that if upwelling winds intensify with climate change the increased forcing could offer mitigation of coastal hypoxia, even as the oxygen levels in upwelled source waters decline.

  17. Accumulation of deuterium oxide in body fluids after ingestion of D/sub 2/O-labeled beverages

    SciTech Connect

    Davis, J.M.; Lamb, D.R.; Burgess, W.A.

    A simple low-cost procedure was developed to compare the temporal profiles of deuterium oxide (D/sub 2/O) accumulation in body fluids after ingestion of D/sub 2/O-labeled solutions. D/sub 2/O concentration was measured in plasma and saliva samples taken at various intervals after ingestion of 20 ml of D/sub 2/O mixed with five solutions differing in carbohydrate and electrolyte concentrations. An infrared spectrometer was used to measure D/sub 2/O in purified samples obtained after a 48-h incubation period during which the water (D/sub 2/O and H/sub 2/O) in the sample was equilibrated with an equal volume of distilled water in a sealedmore » diffusion dish. The procedure yields 100% recoveries of 60-500 ppm D/sub 2/O with an average precision of 5%. When compared with values for distilled water, D/sub 2/O accumulation in serial samples of plasma and saliva was slower for ingested solutions containing 40 and 15% glucose and faster for hypotonic saline and a 6% carbohydrate-electrolyte solution. These differences appear to reflect known differences in gastric emptying and intestinal absorption of these beverages. Therefore, this technique may provide a useful index of the rate of water uptake from ingested beverages into the body fluids.« less

  18. On the deuterium abundance and the importance of stellar mass loss in the interstellar and intergalactic medium

    NASA Astrophysics Data System (ADS)

    van de Voort, Freeke; Quataert, Eliot; Faucher-Giguère, Claude-André; Kereš, Dušan; Hopkins, Philip F.; Chan, T. K.; Feldmann, Robert; Hafen, Zachary

    2018-06-01

    We quantify the gas-phase abundance of deuterium and fractional contribution of stellar mass loss to the gas in cosmological zoom-in simulations from the Feedback In Realistic Environments project. At low metallicity, our simulations confirm that the deuterium abundance is very close to the primordial value. The chemical evolution of the deuterium abundance that we derive here agrees quantitatively with analytical chemical evolution models. We furthermore find that the relation between the deuterium and oxygen abundance exhibits very little scatter. We compare our simulations to existing high-redshift observations in order to determine a primordial deuterium fraction of (2.549 ± 0.033) × 10-5 and stress that future observations at higher metallicity can also be used to constrain this value. At fixed metallicity, the deuterium fraction decreases slightly with decreasing redshift, due to the increased importance of mass-loss from intermediate-mass stars. We find that the evolution of the average deuterium fraction in a galaxy correlates with its star formation history. Our simulations are consistent with observations of the Milky Way's interstellar medium (ISM): the deuterium fraction at the solar circle is 85-92 per cent of the primordial deuterium fraction. We use our simulations to make predictions for future observations. In particular, the deuterium abundance is lower at smaller galactocentric radii and in higher mass galaxies, showing that stellar mass loss is more important for fuelling star formation in these regimes (and can even dominate). Gas accreting on to galaxies has a deuterium fraction above that of the galaxies' ISM, but below the primordial fraction, because it is a mix of gas accreting from the intergalactic medium and gas previously ejected or stripped from galaxies.

  19. Elemental depletions in Antarctic micrometeorites and Arctic cosmic spherules: Comparison and relationships

    NASA Technical Reports Server (NTRS)

    Presper, T.; Kurat, G.; Koeberl, C.; Palme, H.; Maurette, Michel

    1993-01-01

    Antarctic micrometeorites (MM's) and Arctic cosmic spherules (CS's) have bulk compositions comparable to those of chondritic meteorites. However, abundance of Na, Ca, Mn, Ni, Co, and S are commonly lower in MM's and CS's as compared to chondrites. Our SEM, EMP, and INAA studies suggest that these elemental depletions in unmelted MM's are likely to be due to leaching of soluble components from the MM's in the upper atmosphere and the melt ice water. Depletions in CS's appear to be mainly due to volatilization during melting in the atmosphere or to sampling bias during aggregate formation or parent rock break-up.

  20. 26 CFR 52.4682-1 - Ozone-depleting chemicals.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Ozone-depleting chemicals. 52.4682-1 Section 52... EXCISE TAXES (CONTINUED) ENVIRONMENTAL TAXES § 52.4682-1 Ozone-depleting chemicals. (a) Overview. This section provides rules relating to the tax imposed on ozone-depleting chemicals (ODCs) under section 4681...

  1. 26 CFR 52.4682-1 - Ozone-depleting chemicals.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 17 2011-04-01 2011-04-01 false Ozone-depleting chemicals. 52.4682-1 Section 52... EXCISE TAXES (CONTINUED) ENVIRONMENTAL TAXES § 52.4682-1 Ozone-depleting chemicals. (a) Overview. This section provides rules relating to the tax imposed on ozone-depleting chemicals (ODCs) under section 4681...

  2. Children's Models of the Ozone Layer and Ozone Depletion.

    ERIC Educational Resources Information Center

    Christidou, Vasilia; Koulaidis, Vasilis

    1996-01-01

    The views of 40 primary students on ozone and its depletion were recorded through individual, semi-structured interviews. The data analysis resulted in the formation of a limited number of models concerning the distribution and role of ozone in the atmosphere, the depletion process, and the consequences of ozone depletion. Identifies five target…

  3. 26 CFR 52.4682-1 - Ozone-depleting chemicals.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 17 2014-04-01 2014-04-01 false Ozone-depleting chemicals. 52.4682-1 Section 52... EXCISE TAXES (CONTINUED) ENVIRONMENTAL TAXES § 52.4682-1 Ozone-depleting chemicals. (a) Overview. This section provides rules relating to the tax imposed on ozone-depleting chemicals (ODCs) under section 4681...

  4. 26 CFR 52.4682-1 - Ozone-depleting chemicals.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 17 2012-04-01 2012-04-01 false Ozone-depleting chemicals. 52.4682-1 Section 52... EXCISE TAXES (CONTINUED) ENVIRONMENTAL TAXES § 52.4682-1 Ozone-depleting chemicals. (a) Overview. This section provides rules relating to the tax imposed on ozone-depleting chemicals (ODCs) under section 4681...

  5. 26 CFR 1.642(e)-1 - Depreciation and depletion.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Depreciation and depletion. 1.642(e)-1 Section 1... (CONTINUED) INCOME TAXES Estates, Trusts, and Beneficiaries § 1.642(e)-1 Depreciation and depletion. An estate or trust is allowed the deductions for depreciation and depletion, but only to the extent the...

  6. 26 CFR 1.613-1 - Percentage depletion; general rule.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 7 2010-04-01 2010-04-01 true Percentage depletion; general rule. 1.613-1... TAX (CONTINUED) INCOME TAXES (CONTINUED) Natural Resources § 1.613-1 Percentage depletion; general rule. (a) In general. In the case of a taxpayer computing the deduction for depletion under section 611...

  7. Deuterium permeation of amorphous alumina coating on 316L prepared by MOCVD

    NASA Astrophysics Data System (ADS)

    Li, Shuai; He, Di; Liu, Xiaopeng; Wang, Shumao; Jiang, Lijun

    2012-01-01

    The deuterium permeation behavior of the alumina coating on 316L stainless steel prepared by metal organic chemical vapor deposition (MOCVD) was investigated. The alumina coating was also characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). It was found that the as-prepared coating consisted of amorphous alumina. This alumina coating had a dense, crack-free and homogeneous morphology. Although the alumina coating was amorphous, effective suppression of deuterium permeation was demonstrated. The deuterium permeability of the alumina coating was 51-60 times less than that of the 316L stainless steel and 153-335 times less than that of the referred low activation martensitic steels at 860-960 K.

  8. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    NASA Astrophysics Data System (ADS)

    Shimada, Masashi; Hara, Masanori; Otsuka, Teppei; Oya, Yasuhisa; Hatano, Yuji

    2015-08-01

    Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 1026 m-2) at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy was performed with a ramp rate of 10 °C min-1 up to 900 °C, and the samples were annealed at 900 °C for 0.5 h. These procedures were repeated three times to uncover defect-annealing effects on deuterium retention. The results show that deuterium retention decreases approximately 70% for at 500 °C after each annealing, and radiation damages were not annealed out completely even after the 3rd annealing. TMAP modeling revealed the trap concentration decreases approximately 80% after each annealing at 900 °C for 0.5 h.

  9. Deuterium dilution technique for body composition assessment: resolving methodological issues in children with moderate acute malnutrition.

    PubMed

    Fabiansen, Christian; Yaméogo, Charles W; Devi, Sarita; Friis, Henrik; Kurpad, Anura; Wells, Jonathan C

    2017-08-01

    Childhood malnutrition is highly prevalent and associated with high mortality risk. In observational and interventional studies among malnourished children, body composition is increasingly recognised as a key outcome. The deuterium dilution technique has generated high-quality data on body composition in studies of infants and young children in several settings, but its feasibility and accuracy in children suffering from moderate acute malnutrition requires further study. Prior to a large nutritional intervention trial among children with moderate acute malnutrition, we conducted pilot work to develop and adapt the deuterium dilution technique. We refined procedures for administration of isotope doses and collection of saliva. Furthermore, we established that equilibration time in local context is 3 h. These findings and the resulting standard operating procedures are important to improve data quality when using the deuterium dilution technique in malnutrition studies in field conditions, and may encourage a wider use of isotope techniques.

  10. Modelling third harmonic ion cyclotron acceleration of deuterium beams for JET fusion product studies experiments

    NASA Astrophysics Data System (ADS)

    Schneider, M.; Johnson, T.; Dumont, R.; Eriksson, J.; Eriksson, L.-G.; Giacomelli, L.; Girardo, J.-B.; Hellsten, T.; Khilkevitch, E.; Kiptily, V. G.; Koskela, T.; Mantsinen, M.; Nocente, M.; Salewski, M.; Sharapov, S. E.; Shevelev, A. E.; Contributors, JET

    2016-11-01

    Recent JET experiments have been dedicated to the studies of fusion reactions between deuterium (D) and Helium-3 (3He) ions using neutral beam injection (NBI) in synergy with third harmonic ion cyclotron radio-frequency heating (ICRH) of the beam. This scenario generates a fast ion deuterium tail enhancing DD and D3He fusion reactions. Modelling and measuring the fast deuterium tail accurately is essential for quantifying the fusion products. This paper presents the modelling of the D distribution function resulting from the NBI+ICRF heating scheme, reinforced by a comparison with dedicated JET fast ion diagnostics, showing an overall good agreement. Finally, a sawtooth activity for these experiments has been observed and interpreted using SPOT/RFOF simulations in the framework of Porcelli’s theoretical model, where NBI+ICRH accelerated ions are found to have a strong stabilizing effect, leading to monster sawteeth.

  11. Conformational Assessment of Adnectin and Adnectin-Drug Conjugate by Hydrogen/Deuterium Exchange Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Huang, Richard Y.-C.; O'Neil, Steven R.; Lipovšek, Daša; Chen, Guodong

    2018-05-01

    Higher-order structure (HOS) characterization of therapeutic protein-drug conjugates for comprehensive assessment of conjugation-induced protein conformational changes is an important consideration in the biopharmaceutical industry to ensure proper behavior of protein therapeutics. In this study, conformational dynamics of a small therapeutic protein, adnectin 1, together with its drug conjugate were characterized by hydrogen/deuterium exchange mass spectrometry (HDX-MS) with different spatial resolutions. Top-down HDX allows detailed assessment of the residue-level deuterium content in the payload conjugation region. HDX-MS dataset revealed the ability of peptide-based payload/linker to retain deuterium in HDX experiments. Combined results from intact, top-down, and bottom-up HDX indicated no significant conformational changes of adnectin 1 upon payload conjugation. [Figure not available: see fulltext.

  12. Quasi-Isentropic Compressibility of Deuterium at a Pressure of 12 TPa

    NASA Astrophysics Data System (ADS)

    Mochalov, M. A.; Il'kaev, R. I.; Fortov, V. E.; Mikhailov, A. L.; Arinin, V. A.; Blikov, A. O.; Komrakov, V. A.; Maksimkin, I. P.; Ogorodnikov, V. A.; Ryzhkov, A. V.

    2018-04-01

    An experimental result for the quasi-isentropic compressibility of a strongly nonideal deuterium plasma compressed in a spherical device by the pressure P = 11400 GPa (114 Mbar) to the density ρ ≈ 10g/cm3 has been reported. The characteristics of the experimental device, diagnostic methods, and experimental results have been described. The trajectory of motion of metallic shells compressing a deuterium plasma has been recorded using intense pulsed sources of X rays with the boundary energy of electrons up to 60 MeV. The deuterium plasma density ρ ≈ 10g/cm3 has been determined from the measured radius of the shell at the time of its "stop." The pressure of the compressed plasma has been determined from gas-dynamic calculations taking into account the real characteristics of the experimental device.

  13. Efficient source for the production of ultradense deuterium D(-1) for laser-induced fusion (ICF).

    PubMed

    Andersson, Patrik U; Lönn, Benny; Holmlid, Leif

    2011-01-01

    A novel source which simplifies the study of ultradense deuterium D(-1) is now described. This means one step further toward deuterium fusion energy production. The source uses internal gas feed and D(-1) can now be studied without time-of-flight spectral overlap from the related dense phase D(1). The main aim here is to understand the material production parameters, and thus a relatively weak laser with focused intensity ≤10(12) W cm(-2) is employed for analyzing the D(-1) material. The properties of the D(-1) material at the source are studied as a function of laser focus position outside the emitter, deuterium gas feed, laser pulse repetition frequency and laser power, and temperature of the source. These parameters influence the D(-1) cluster size, the ionization mode, and the laser fragmentation patterns.

  14. Electrolyte depletion in white-nose syndrome bats

    USGS Publications Warehouse

    Cryan, Paul M.; Meteyer, Carol Uphoff; Blehert, David S.; Lorch, Jeffrey M.; Reeder, DeeAnn M.; Turner, Gregory G.; Webb, Julie; Behr, Melissa; Verant, Michelle L.; Russell, Robin E.; Castle, Kevin T.

    2013-01-01

    The emerging wildlife disease white-nose syndrome is causing widespread mortality in hibernating North American bats. White-nose syndrome occurs when the fungus Geomyces destructans infects the living skin of bats during hibernation, but links between infection and mortality are underexplored. We analyzed blood from hibernating bats and compared blood electrolyte levels to wing damage caused by the fungus. Sodium and chloride tended to decrease as wing damage increased in severity. Depletion of these electrolytes suggests that infected bats may become hypotonically dehydrated during winter. Although bats regularly arouse from hibernation to drink during winter, water available in hibernacula may not contain sufficient electrolytes to offset winter losses caused by disease. Damage to bat wings from G. destructans may cause life-threatening electrolyte imbalances.

  15. Method for depleting BWRs using optimal control rod patterns

    SciTech Connect

    Taner, M.S.; Levine, S.H.; Hsiao, M.Y.

    1991-01-01

    Control rod (CR) programming is an essential core management activity for boiling water reactors (BWRs). After establishing a core reload design for a BWR, CR programming is performed to develop a sequence of exposure-dependent CR patterns that assure the safe and effective depletion of the core through a reactor cycle. A time-variant target power distribution approach has been assumed in this study. The authors have developed OCTOPUS to implement a new two-step method for designing semioptimal CR programs for BWRs. The optimization procedure of OCTOPUS is based on the method of approximation programming and uses the SIMULATE-E code for nucleonicsmore » calculations.« less

  16. Measurement of milk intake in suckling llamas (Lama glama) using deuterium oxide dilution.

    PubMed

    Riek, A; Gerken, M; Moors, E

    2007-02-01

    The objective of the study was to estimate daily milk intake in llama crias and relate nutrient intakes at peak lactation to growth data. Milk intake in 11 suckling llamas was estimated from water kinetics using deuterium oxide (D2O) at d 17, 66, and 128 postpartum. Daily milk intakes averaged 2.6, 2.3, and 2.0 kg at 17, 66, and 128 d postpartum, respectively. Milk intake decreased with age when expressed as daily amount, percentage of body weight (BW), or per kilogram of metabolic size, but the influence of age was eliminated when expressed per gram of daily gain. Because llamas only have one young per parturition, milk intake was equivalent to the daily milk output of the dam, which ranged from 27.6 to 96.9 g/kg of maternal BW(0.75). Compared with different ruminant species, milk production in llamas appears to lie between wild and domestic ruminants used for meat production. Nutrients (dry matter, fat, protein, and lactose) and energy intakes from the milk calculated by combining milk intake and milk composition data decreased with age when expressed as daily amount or per 100 g of BW, but when expressed per gram of daily gain, no clear trend was observed. Maintenance requirement for suckling llamas at peak lactation (17 d postpartum) was 312 kJ of ME/kg of BW(0.83). Combined with milk composition data, the present milk intake estimations at different stages of the lactation can be used to establish recommendations for nutrient and energy requirements of suckling llamas.

  17. Deuterium oxide dilution and body composition in overweight and obese schoolchildren aged 6-9 years.

    PubMed

    Bila, Wendell Costa; Freitas, André Everton de; Galdino, Alexsandro Sobreira; Ferriolli, Eduardo; Pfrimer, Karina; Lamounier, Joel Alves

    2016-01-01

    To correlate different methods of body composition assessment in overweight or obese schoolchildren, using deuterium oxide (D2O) dilution as a reference. Percentage of total body water (%TBW), fat free mass (%FFM), and body fat (%BF) were assessed by D2O and tetrapolar electrical bioimpedance analysis (BIA) in 54 obese and overweight students aged 6-9 years. Skinfold thickness (ST), body mass index (BMI), conicity index (CI), waist circumference (WC), waist-to-height ratio (WHtR), and waist-to-hip (WHR) ratio were also used. Mean values for body composition were 38.4%±8.4% BF, 44.9%±6.1% TBW and 61.6%±8.4% FFM. There was no significant difference in body weight, body fat mass (FM), TBW, and FFM between genders. Regarding D2O, ST underestimated %BF, and overestimated %FFM in both genders (p<0.05). BIA overestimated %TBW in the group as a whole and in males (p<0.05). The only positive and strong correlations occurred in females regarding the WC (σ=0.679), CI (r=0.634), and WHtR (r=0.666). In this sample of obese and overweight children, there were strong correlations between body composition measured by D2O and some indices and anthropometric indicators in females, but there was no positive and strong correlation of fat tissue with the indices/indicators at all ages and in both genders. Copyright © 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  18. Potential For Stratospheric Ozone Depletion During Carboniferous

    NASA Astrophysics Data System (ADS)

    Bill, M.; Goldstein, A. H.

    Methyl bromide (CH3Br) constitutes the largest source of bromine atoms to the strato- sphere whereas methyl chloride (CH3Cl) is the most abundant halocarbon in the tro- posphere. Both gases play an important role in stratospheric ozone depletion. For in- stance, Br coupled reactions are responsible for 30 to 50 % of total ozone loss in the polar vortex. Currently, the largest natural sources of CH3Br and CH3Cl appear to be biological production in the oceans, inorganic production during biomass burning and plant production in salt marsh ecosystems. Variations of paleofluxes of CH3Br and CH3Cl can be estimated by analyses of oceanic paleoproductivity, stratigraphic analyses of frequency and distribution of fossil charcoal indicating the occurrence of wildfires, and/or by paleoreconstruction indicating the extent of salt marshes. Dur- ing the lower Carboniferous time (Tournaisian-Visean), the southern margin of the Laurasian continent was characterized by charcoal deposits. Estimation on frequency of charcoal layers indicates that wildfires occur in a range of 3-35 years (Falcon-Lang 2000). This suggests that biomass burning could be an important source of CH3Br and CH3Cl during Tournaisian-Viesan time. During Tounaisian and until Merame- cian carbon and oxygen isotope records have short term oscillations (Bruckschen et al. 1999, Mii et al. 1999). Chesterian time (mid- Carboniferous) is marked by an in- crease in delta18O values ( ~ 2 permil) and an increase of glacial deposit frequency suggesting lower temperatures. The occurrence of glacial deposits over the paleopole suggests polar conditions and the associated special features of polar mete- orology such as strong circumpolar wind in the stratosphere (polar vortex) and polar stratospheric clouds. Thus, conditions leading to polar statospheric ozone depletion can be found. Simultaneously an increase in delta13C values is documented. We interpret the positive shift in delta13C as a result of higher bioproductivity

  19. Research Spotlight: Groundwater is being depleted rapidly in California's Central Valley

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-03-01

    Groundwater is being depleted in California's Central Valley at a rapid rate, according to data from the Gravity Recovery and Climate Experiment (GRACE) satellite. Famiglietti et al. analyzed 78 months of GRACE data covering October 2003 to March 2010 to estimate water storage changes in California's Sacramento and San Joaquin river basins. They found that the basins are losing water at a rate of about 30 millimeters per year equivalent water height, or a total of about 30 cubic kilometers over the 78-month period. Furthermore, they found that two thirds of this loss, or a total of 20 cubic kilometers for the study period, came from groundwater depletion in the Central Valley. Quantifying groundwater depletion can be challenging in many areas because of a lack of monitoring infrastructure and reporting requirements; the study shows that satellite-based monitoring can be a useful way to track groundwater volumes. The authors warn that the current rate of groundwater depletion in the Central Valley may be unsustainable and could have “potentially dire consequences for the economic and food security of the United States.” (Geophysical Research Letters, doi:10.1029/2010GL046442, 2011)

  20. A modern depleted uranium manufacturing facility

    SciTech Connect

    Zagula, T.A.

    1995-07-01

    The Specific Manufacturing Capabilities (SMC) Project located at the Idaho National Engineering Laboratory (INEL) and operated by Lockheed Martin Idaho Technologies Co. (LMIT) for the Department of Energy (DOE) manufactures depleted uranium for use in the U.S. Army MIA2 Abrams Heavy Tank Armor Program. Since 1986, SMC has fabricated more than 12 million pounds of depleted uranium (DU) products in a multitude of shapes and sizes with varying metallurgical properties while maintaining security, environmental, health and safety requirements. During initial facility design in the early 1980`s, emphasis on employee safety, radiation control and environmental consciousness was gaining momentum throughout themore » DOE complex. This fact coupled with security and production requirements forced design efforts to focus on incorporating automation, local containment and computerized material accountability at all work stations. The result was a fully automated production facility engineered to manufacture DU armor packages with virtually no human contact while maintaining security, traceability and quality requirements. This hands off approach to handling depleted uranium resulted in minimal radiation exposures and employee injuries. Construction of the manufacturing facility was complete in early 1986 with the first armor package certified in October 1986. Rolling facility construction was completed in 1987 with the first certified plate produced in the fall of 1988. Since 1988 the rolling and manufacturing facilities have delivered more than 2600 armor packages on schedule with 100% final product quality acceptance. During this period there was an annual average of only 2.2 lost time incidents and a single individual maximum radiation exposure of 150 mrem. SMC is an example of designing and operating a facility that meets regulatory requirements with respect to national security, radiation control and personnel safety while achieving production schedules and product

  1. Rhenium Disulfide Depletion-Load Inverter

    NASA Astrophysics Data System (ADS)

    McClellan, Connor; Corbet, Chris; Rai, Amritesh; Movva, Hema C. P.; Tutuc, Emanuel; Banerjee, Sanjay K.

    2015-03-01

    Many semiconducting Transition Metal Dichalcogenide (TMD) materials have been effectively used to create Field-Effect Transistor (FET) devices but have yet to be used in logic designs. We constructed a depletion-load voltage inverter using ultrathin layers of Rhenium Disulfide (ReS2) as the semiconducting channel. This ReS2 inverter was fabricated on a single micromechanically-exfoliated flake of ReS2. Electron beam lithography and physical vapor deposition were used to construct Cr/Au electrical contacts, an Alumina top-gate dielectric, and metal top-gate electrodes. By using both low (Aluminum) and high (Palladium) work-function metals as two separate top-gates on a single ReS2 flake, we create a dual-gated depletion mode (D-mode) and enhancement mode (E-mode) FETs in series. Both FETs displayed current saturation in the output characteristics as a result of the FET ``pinch-off'' mechanism and On/Off current ratios of 105. Field-effect mobilities of 23 and 17 cm2V-1s-1 and subthreshold swings of 97 and 551 mV/decade were calculated for the E-mode and D-mode FETs, respectively. With a supply voltage of 1V, at low/negative input voltages the inverter output was at a high logic state of 900 mV. Conversely with high/positive input voltages, the inverter output was at a low logic state of 500 mV. The inversion of the input signal demonstrates the potential for using ReS2 in future integrated circuit designs and the versatility of depletion-load logic devices for TMD research. NRI SWAN Center and ARL STTR Program.

  2. Lateral Parabrachial Nucleus Serotonergic Mechanisms and Salt Appetite Induced by Sodium Depletion

    NASA Technical Reports Server (NTRS)

    Menani, Jose Vanderlei; DeLuca, Laurival Antonio, Jr.; Johnson, Alan Kim

    1998-01-01

    This study investigated the effects of bilateral injections of a serotonin (5-HT) receptor agonist into the lateral parabrachial nucleus on the intake of NaCl and water induced by 24-h water deprivation or by sodium depletion followed by 24 h of sodium deprivation (injection of the diuretic furosemide plus 24 h of d sodium-deficient diet). Rats had stainless steel cannulas implanted bilaterally into the LPBN. Bilateral LPBN injections of the serotonergic 5-HT(1/2) receptor antagonist methysergide (4 micro-g/200 nl at each site) increased hypertonic NaCl intake when tested 24 h after sodium depletion and after 24 h of water deprivation. Water intake also increased after bilateral injections of methysergide into the LPBN. In contrast, the intake of a palatable solution (0.06 M sucrose) under body fluid-replete conditions was not changed after bilateral LPBN methysergide injections. The results show that serotonergic mechanisms in the LPBN modulate water and sodium intake induced by volume depletion and sodium loss. The finding that sucrose intake was not affected by LPBN serotonergic blockade suggests that the effects of the methysergide treatment on the intakes of water and NaCl are not due to a mechanism producing a nonspecific enhancement of all ingestive behaviors.

  3. Late-stage magmatic outgassing from a volatile-depleted Moon

    NASA Astrophysics Data System (ADS)

    Day, James M. D.; Moynier, Frédéric; Shearer, Charles K.

    2017-09-01

    The abundance of volatile elements and compounds, such as zinc, potassium, chlorine, and water, provide key evidence for how Earth and the Moon formed and evolved. Currently, evidence exists for a Moon depleted in volatile elements, as well as reservoirs within the Moon with volatile abundances like Earth’s depleted upper mantle. Volatile depletion is consistent with catastrophic formation, such as a giant impact, whereas a Moon with Earth-like volatile abundances suggests preservation of these volatiles, or addition through late accretion. We show, using the “Rusty Rock” impact melt breccia, 66095, that volatile enrichment on the lunar surface occurred through vapor condensation. Isotopically light Zn (δ66Zn = -13.7‰), heavy Cl (δ37Cl = +15‰), and high U/Pb supports the origin of condensates from a volatile-poor internal source formed during thermomagmatic evolution of the Moon, with long-term depletion in incompatible Cl and Pb, and lesser depletion of more-compatible Zn. Leaching experiments on mare basalt 14053 demonstrate that isotopically light Zn condensates also occur on some mare basalts after their crystallization, confirming a volatile-depleted lunar interior source with homogeneous δ66Zn ≈ +1.4‰. Our results show that much of the lunar interior must be significantly depleted in volatile elements and compounds and that volatile-rich rocks on the lunar surface formed through vapor condensation. Volatiles detected by remote sensing on the surface of the Moon likely have a partially condensate origin from its interior.

  4. Late-stage magmatic outgassing from a volatile-depleted Moon

    PubMed Central

    Moynier, Frédéric; Shearer, Charles K.

    2017-01-01

    The abundance of volatile elements and compounds, such as zinc, potassium, chlorine, and water, provide key evidence for how Earth and the Moon formed and evolved. Currently, evidence exists for a Moon depleted in volatile elements, as well as reservoirs within the Moon with volatile abundances like Earth’s depleted upper mantle. Volatile depletion is consistent with catastrophic formation, such as a giant impact, whereas a Moon with Earth-like volatile abundances suggests preservation of these volatiles, or addition through late accretion. We show, using the “Rusty Rock” impact melt breccia, 66095, that volatile enrichment on the lunar surface occurred through vapor condensation. Isotopically light Zn (δ66Zn = −13.7‰), heavy Cl (δ37Cl = +15‰), and high U/Pb supports the origin of condensates from a volatile-poor internal source formed during thermomagmatic evolution of the Moon, with long-term depletion in incompatible Cl and Pb, and lesser depletion of more-compatible Zn. Leaching experiments on mare basalt 14053 demonstrate that isotopically light Zn condensates also occur on some mare basalts after their crystallization, confirming a volatile-depleted lunar interior source with homogeneous δ66Zn ≈ +1.4‰. Our results show that much of the lunar interior must be significantly depleted in volatile elements and compounds and that volatile-rich rocks on the lunar surface formed through vapor condensation. Volatiles detected by remote sensing on the surface of the Moon likely have a partially condensate origin from its interior. PMID:28827322

  5. Scientific assessment of ozone depletion: 1991

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Over the past few years, there have been highly significant advances in the understanding of the impact of human activities on the Earth's stratospheric ozone layer and the influence of changes in chemical composition of the radiative balance of the climate system. Specifically, since the last international scientific review (1989), there have been five major advances: (1) global ozone decreases; (2) polar ozone; (3) ozone and industrial halocarbons; (4) ozone and climate relations; and (5) ozone depletion potentials (ODP's) and global warming potentials (GWP's). These topics and others are discussed.

  6. Depletion of the Outer Asteroid Belt

    PubMed

    Liou; Malhotra

    1997-01-17

    During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.

  7. Capstone Depleted Uranium Aerosols: Generation and Characterization

    SciTech Connect

    Parkhurst, MaryAnn; Szrom, Fran; Guilmette, Ray

    2004-10-19

    In a study designed to provide an improved scientific basis for assessing possible health effects from inhaling depleted uranium (DU) aerosols, a series of DU penetrators was fired at an Abrams tank and a Bradley fighting vehicle. A robust sampling system was designed to collect aerosols in this difficult environment and continuously monitor the sampler flow rates. Aerosols collected were analyzed for uranium concentration and particle size distribution as a function of time. They were also analyzed for uranium oxide phases, particle morphology, and dissolution in vitro. The resulting data provide input useful in human health risk assessments.

  8. Depletion of the Outer Asteroid Belt

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi; Malhotra, Renu

    1997-01-01

    During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.

  9. Research on laser-removal of a deuterium deposit from a graphite sample

    NASA Astrophysics Data System (ADS)

    Kubkowska, M.; Skladnik-Sadowska, E.; Malinowski, K.; Sadowski, M. J.; Rosinski, M.; Gasior, P.

    2014-04-01

    The paper presents experimental results of investigation of a removal of deuterium deposits from a graphite target by means of pulsed laser beams. The sample was a part of the TEXTOR limiter with a deuterium-deposited layer. That target was located in the vacuum chamber, pumped out to 5×10-5 Torr, and it was irradiated with a Nd:YAG laser, which generated 3.5-ns pulses of energy of 0.5 J at λ1 = 1063 nm, or 0.1 J at λ3 = 355 nm.

  10. Simulations and observations of plasma depletion, ion composition, and airglow emissions in two auroral ionospheric depletion experiments

    NASA Technical Reports Server (NTRS)

    Yau, A. W.; Whalen, B. A.; Harris, F. R.; Gattinger, R. L.; Pongratz, M. B.

    1985-01-01

    Observations of plasma depletion, ion composition modification, and airglow emissions in the Waterhole experiments are presented. The detailed ion chemistry and airglow emission processes related to the ionospheric hole formation in the experiment are examined, and observations are compared with computer simulation results. The latter indicate that the overall depletion rates in different parts of the depletion region are governed by different parameters.

  11. Studies on the determination of surface deuterium in AISI 1062, 4037, and 4140 steels by secondary ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Sastri, V. S.; Donepudi, V. S.; McIntyre, N. S.; Johnston, D.; Revie, R. W.

    1988-12-01

    The concentration of deuterium at the surface of cathodically charged high strength steels AISI 1062, 4037, and 4140 has been determined by secondary ion mass spectrometry (SIMS). The beneficial effects of pickling in NAP (a mixture of nitric, acetic, and phosphoric acids) to remove surfacebound deuterium have been observed.

  12. 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.

    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

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

    DOE PAGES

    Bang, W.; Quevedo, H. J.; Bernstein, A. C.; ...

    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

  14. Mesospheric ionization and O2 1Delta(g) depletion

    NASA Technical Reports Server (NTRS)

    Spear, K. A.; Solomon, S.

    1987-01-01

    Observations of O2 1Delta(g) emission during solar proton events reveal large depletions below 80 and near 90 km. The lower-altitude depletions are believed to be due to odd hydrogen production and associated depletion of ozone, but the mechanism producing the depletion near 90 km has not yet been established. In this paper, it is proposed that an exothermic charge exchange reaction between O2(+) and O2 1Delta(g) is likely to be responsible for these high-altitude depletions. In particular, it is shown that the vertical structure of the observed change in airglow emission is consistent with this mechanism.

  15. Antioxidant Depletion and Service Life Prediction for HDPE Geomembranes Exposed to Low-Level Radioactive Waste Leachate

    DOE PAGES

    Tian, Kuo; Benson, Craig H.; Tinjum, James M.; ...

    2017-06-01

    Antioxidant depletion was evaluated in high-density polyethylene (HDPE) geomembrane (GM) coupons immersed in radioactive synthetic leachate (RSL) representative of leachate in low-level radioactive waste (LLW) disposal facilities operated by the U.S. Department of Energy’s environmental restoration programs. Depletion was assessed at four temperatures (25, 50, 70, and 90°C). Comparative tests were conducted with nonradioactive synthetic leachate (NSL) having the same chemistry as RSL, except radionuclides were excluded. Control tests were conducted with deionized (DI) water. One-sided exposure tests were also conducted with the HDPE GM in RSL at 70 and 90°C. Specimens were removed periodically and tested to determine antioxidantmore » depletion, melt flow index (MFI), crystallinity, and stress crack resistance. Standard and high-pressure oxidative induction time (OIT) tests were conducted to measure antioxidant depletion. Antioxidant depletion rates in RSL were only slightly greater than those in NSL, indicating that radionuclides in the LLW leachate had only minor effect on antioxidant depletion. Antioxidant depletion in RSL and NSL occurred 1.1–1.9 times faster than in DI water. Antioxidant depletion in HDPE GMs exposed to RSL and NSL at 90°C was complete after 12 months. MFI decreased systematically after 15 months of immersion, which is indicative of crosslinking due to oxidation. Crystallinity also decreased slightly after 12 months, whereas stress crack resistance (SCR) showed no trend over the immersion period. Arrhenius modeling was used to extrapolate the laboratory data at elevated temperatures to a typical LLWliner at 15°C. Predicted time for antioxidant depletion for a 2-mm-thick HDPE GM in a composite liner in contact with LLW leachate is estimated to be 730 years. The total service life of HDPE GMs in contact with LLWleachate is estimated to be at least 1975 years.« less

  16. Antioxidant Depletion and Service Life Prediction for HDPE Geomembranes Exposed to Low-Level Radioactive Waste Leachate

    SciTech Connect

    Tian, Kuo; Benson, Craig H.; Tinjum, James M.

    Antioxidant depletion was evaluated in high-density polyethylene (HDPE) geomembrane (GM) coupons immersed in radioactive synthetic leachate (RSL) representative of leachate in low-level radioactive waste (LLW) disposal facilities operated by the U.S. Department of Energy’s environmental restoration programs. Depletion was assessed at four temperatures (25, 50, 70, and 90°C). Comparative tests were conducted with nonradioactive synthetic leachate (NSL) having the same chemistry as RSL, except radionuclides were excluded. Control tests were conducted with deionized (DI) water. One-sided exposure tests were also conducted with the HDPE GM in RSL at 70 and 90°C. Specimens were removed periodically and tested to determine antioxidantmore » depletion, melt flow index (MFI), crystallinity, and stress crack resistance. Standard and high-pressure oxidative induction time (OIT) tests were conducted to measure antioxidant depletion. Antioxidant depletion rates in RSL were only slightly greater than those in NSL, indicating that radionuclides in the LLW leachate had only minor effect on antioxidant depletion. Antioxidant depletion in RSL and NSL occurred 1.1–1.9 times faster than in DI water. Antioxidant depletion in HDPE GMs exposed to RSL and NSL at 90°C was complete after 12 months. MFI decreased systematically after 15 months of immersion, which is indicative of crosslinking due to oxidation. Crystallinity also decreased slightly after 12 months, whereas stress crack resistance (SCR) showed no trend over the immersion period. Arrhenius modeling was used to extrapolate the laboratory data at elevated temperatures to a typical LLWliner at 15°C. Predicted time for antioxidant depletion for a 2-mm-thick HDPE GM in a composite liner in contact with LLW leachate is estimated to be 730 years. The total service life of HDPE GMs in contact with LLWleachate is estimated to be at least 1975 years.« less

  17. Water

    USGS Publications Warehouse

    Leopold, Luna Bergere; Baldwin, Helene L.

    1962-01-01

    What do you use water for?If someone asked you this question you would probably think right away of water for drinking. Then you would think of water for bathing, brushing teeth, flushing the toilet. Your list would get longer as you thought of water for cooking, washing the dishes, running the garbage grinder. Water for lawn watering, for play pools, for swimming pools, for washing the car and the dog. Water for washing machines and for air conditioning. You can hardly do without water for fun and pleasure—water for swimming, boating, fishing, water-skiing, and skin diving. In school or the public library, you need water to wash your hands, or to have a drink. If your home or school bursts into flames, quantities of water are needed to put it out.In fact, life to Americans is unthinkable without large supplies of fresh, clean water. If you give the matter a little thought, you will realize that people in many countries, even in our own, may suffer from disease and dirt simply because their homes are not equipped with running water. Imagine your own town if for some reason - an explosion, perhaps - water service were cut off for a week or several weeks. You would have to drive or walk to a neighboring town and bring water back in pails. Certainly if people had to carry water themselves they might not be inclined to bathe very often; washing clothes would be a real chore.Nothing can live without water. The earth is covered by water over three-fourths of its surface - water as a liquid in rivers, lakes and oceans, and water as ice and snow on the tops of high mountains and in the polar regions. Only one-quarter of our bodies is bone and muscle; the other three-fourths is made of water. We need water to live, and so do plants and animals. People and animals can live a long time without food, but without water they die in a few days. Without water, everything would die, and the world would turn into a huge desert.

  18. Incorporation of copper ions into crystals of T2 copper-depleted laccase from Botrytis aclada

    SciTech Connect

    Osipov, E. M., E-mail: e.m.osipov@gmail.com; Polyakov, K. M.; Engelhardt Institute of Molecular Biology, Vavilova str. 32, Moscow 119991

    2015-11-18

    The restoration of the native form of laccase from B. aclada from the type 2 copper-depleted form of the enzyme was investigated. Copper ions were found to be incorporated into the active site after soaking the depleted enzyme in a Cu{sup +}-containing solution. Laccases belong to the class of multicopper oxidases catalyzing the oxidation of phenols accompanied by the reduction of molecular oxygen to water without the formation of hydrogen peroxide. The activity of laccases depends on the number of Cu atoms per enzyme molecule. The structure of type 2 copper-depleted laccase from Botrytis aclada has been solved previously. Withmore » the aim of obtaining the structure of the native form of the enzyme, crystals of the depleted laccase were soaked in Cu{sup +}- and Cu{sup 2+}-containing solutions. Copper ions were found to be incorporated into the active site only when Cu{sup +} was used. A comparative analysis of the native and depleted forms of the enzymes was performed.« less

  19. Local Interstellar Medium Properties and Deuterium Abundances for the Lines of Sight Toward HR 1099, 31 Comae, beta Ceti, and beta Cassiopeiae

    NASA Technical Reports Server (NTRS)

    Piskunov, Nikolai; Wood, Brian E.; Linsky, Jeffrey L.; Dempsey, Robert C.; Ayres, Thomas R.

    1997-01-01

    We analyze Goddard High-Resolution Spectrograph data to infer the properties of local interstellar gas and the Deuterium/Hydrogen (D/H) ratio for lines of sight toward four nearby late-type stars-HR 1099, 31 Comae, beta Ceti, and beta Cassiopeiae. The data consist of spectra of the hydrogen and deuterium Lyman-(alpha) lines, and echelle spectra of the Mg IIh and k lines toward all stars except beta Cas. Spectra of the RS CVn-type spectroscopic binary system HR 1099 were obtained near opposite quadratures to determine the intrinsic stellar emission line profile and the interstellar absorption separately. Multiple-velocity components were found toward HR 1099 and beta Cet. The spectra of 31 Com and beta Cet are particularly interesting because they sample lines of sight toward the north and south Galactic poles, respectively, for which H I and D I column densities were not previously available. The north Galactic pole appears to be a region of low hydrogen density like the 'interstellar tunnel' toward epsilon CMa. The temperature and turbulent velocities of the Local InterStellar Medium (LISM) that we measure for the lines of sight toward HR 1099, 31 Com, beta Cet, and beta Cas are similar to previously measured values (T approx.7000 K and xi = 1.0-1.6 km/s). The deuterium/hydrogen ratios found for these lines of sight are also consistent with previous measurements of other short lines of sight, which suggest D/H approx. 1.6 x 10(sup -5). In contrast, the Mg abundance measured for the beta Cet line of sight (implying a logarithmic depletion of D(Mg) = +0.30 +/- 0.15) is about 5 times larger than the Mg abundance previously observed toward alpha Cen, and about 20 times larger than all other previous measurements for the LISM. These results demonstrate that metal abundances in the LISM vary greatly over distances of only a few parsecs.

  20. A Deuterium NMR Study of Bent-Core Liquid Crystals. 1; Synthesis and Characterization of Deuterium-Labeled Oxadiazole-Containing Liquid Crystals

    NASA Technical Reports Server (NTRS)

    Dingemans, Theo J.; Madsen, Louis A.; Samulski, Edward T.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    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.