Method of deuterium isotope separation using ethylene and ethylene dichloride

International Nuclear Information System (INIS)

Benson, S.W.

1982-01-01

Compounds enriched in deuterium may be obtained from ethylene, vinyl chloride, 1,2-dichloroethane, or propylene by laser isotope separation. Normal molecules of these organic compounds are exposed to infrared laser radiation of a suitable wavelength. Substantially all of the deuterium-containing molecules exposed to the laser can be selectively dissociated and the deuterium-containing products separated from the starting material and other reaction products. The deuterium-containing molecules can be burned to form water with an enriched deuterium content, or pyrolized to form hydrogen gas enriched in deuterium

Deuterium isotope effects in condensed-phase thermochemical decomposition reactions of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine

International Nuclear Information System (INIS)

Shackelford, S.A.; Coolidge, M.B.; Goshgarian, B.B.; Loving, B.A.; Rogers, R.N.; Janney, J.L.; Ebinger, M.H.

1985-01-01

The deuterium isotope effect was applied to condensed-phase thermochemical reactions of HMX and HMX-d 8 by using isothermal techniques. Dissimilar deuterium isotope effects revealed a mechanistic dependence of HMX upon different physical states which may singularly predominate in a specific type of thermal event. Solid-state HMX thermochemical decomposition produces a primary deuterium isotope effect (DIE), indicating that covalent C-H bond rupture is the rate-controlling step in this phase. An apparent inverse DIE is displayed by the mixed melt phase and can be attributed to C-H bond contraction during a weakening of molecular lattice forces as the solid HMX liquefies. The liquid-state decomposition rate appears to be controlled by ring C-N bond cleavage as evidenced by a secondary DIE and higher molecular weight products. These results reveal a dependence of the HMX decomposition process on physical state and lead to a broader mechanistic interpretation which explains the seemingly contradictory data found in current literature reviews. 33 references, 9 figures, 5 tables

Secondary α-deuterium isotope effects as a probe to the relationship between structure and mechanism of pyrolysis of secondary azoalkanes

International Nuclear Information System (INIS)

Grizzle, P.L.

1975-01-01

This study was carried out to investigate the mechanism of azoalkane thermolysis and the effect of molecular structure on the potential-energy hypersurface for pyrolysis utilizing secondary α-deuterium isotope effects. Since the magnitude of the α-effect for 1,1'-diphenylazoethane is of singular importance in the interpretation of those for related compounds, it has been redetermined. To investigate the effect of molecular structure on the potential-energy hypersurface for thermolysis, α-effects have been determined for 2,2,2',2'-tetramethyl-1,1'-diphenylazoethane and (2,2-dimethyl-1-phenylpropyl)azomethane; the inability to prepare these compounds by conventional methods necessitated the development of a new method for synthesis of secondary azoalkanes. A convenient synthesis of secondary azo compounds is reported. Secondary α-deuterium isotope effects were obtained for the thermal decomposition of 1,1'-diphenylazoethane (III) and 1,1'-diphenylazoethane-1,1'-d 2 (III-d 2 ). The isotope effect is entirely consistent with a simultaneous one-step thermolysis mechanism. Secondary α-deuterium isotope effects and activation parameters were obtained in the thermolysis of 2,2,2',2'-tetramethyl-1,1'-diphenylazopropane (VIII) and (2,2-dimethyl-1-phenylpropyl)azomethane (IX). The data for VIII is considered in terms of both a one- and two-step thermolysis mechanism. The α-effect and activation energy for VIII are not obviously reconcilable with a one-step mechanism. The α-effects, activation energies, and rates of thermolysis for VIII, IX, and (1-phenylethyl)azomethane are most easily rationalized by a two-step mechanism

Deuterium/hydrogen isotope exchange on beryllium and beryllium nitride; Deuterium/Wasserstoff-Isotopenaustausch an Beryllium und Berylliumnitrid

Energy Technology Data Exchange (ETDEWEB)

Dollase, Petra; Eichler, Michael; Koeppen, Martin; Dittmar, Timo; Linsmeier, Christian [Forschungszentrum Juelich GmbH, Institut fuer Energie- und Klimaforschung - Plasmaphysik (Germany)

2016-07-01

In the fusion experiments JET and ITER, the first wall is made up of beryllium. The use of nitrogen is discussed for radiative cooling in the divertor. This can react with the surface of the first wall to form beryllium nitride (Be{sub 3}N{sub 2}). The hydrogen isotopes deuterium and tritium, which react in the fusion reaction to helium and a neutron, are used as fuel. Since the magnetic confinement of the plasma is not perfect, deuterium and tritium ions are also found on the beryllium wall and can accumulate there. This should be avoided due to the radioactivity of tritium. Therefore the isotope exchange with deuterium is investigated to regenerate the first wall. We investigate the isotopic exchange of deuterium and protium in order to have not to work with radioactive tritium. The ion bombardment is simulated with an ion source. With voltages up to a maximum of 5 kV, deuterium and protic hydrogen ions are implanted in polycrystalline Be and Be{sub 3}N{sub 2}. The samples are then analyzed in situ using X-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS). Subsequently, samples prepared under the same conditions are characterized ex-situ by means of nuclear reaction analysis (NRA). [German] In den Fusionsexperimenten JET und ITER besteht die erste Wand im Hauptraum aus Beryllium (Be). Zur Strahlungskuehlung im Divertor wird der Einsatz von Stickstoff diskutiert. Dieser kann mit der Oberflaeche der ersten Wand zu Berylliumnitrid (Be{sub 3}N{sub 2}) reagieren. Als Brennstoff werden die Wasserstoffisotope Deuterium und Tritium eingesetzt, die in der Fusionsreaktion zu Helium und einem Neutron reagieren. Da der magnetische Einschluss des Plasmas nicht perfekt ist, treffen auch Deuterium- und Tritiumionen auf die Berylliumwand auf und koennen sich dort anreichern. Das soll aufgrund der Radioaktivitaet von Tritium unbedingt vermieden werden. Daher wird zur Regenerierung der ersten Wand der Isotopenaustausch mit Deuterium untersucht. Wir

Stable Oxygen-18 and Deuterium Isotopes

DEFF Research Database (Denmark)

Müller, Sascha

The application of stable Oxygen-18 (18O) and Deuterium (2H) isotopes, as a tracer for fluxes between different compartments of the water cycle was subject of the present PhD-thesis. During a three year period, temporal data from a wide range of water cycle constituents was collected from...... the Skjern River catchment, Denmark. The presented applications focused on studying the isotopic 'input signal' to the hydrosphere in the form of precipitation, the isotopic 'output signal' with its related dynamic processes at a coastal saltwater-freshwater interface (groundwater isotopes) and the temporal...... development within a given lowland headwater catchment (stream water isotopes). Based on our investigations on the precipitation isotopic composition a local meteoric water line (LMWL) was constructed and expressed as: δ2H=7.4 δ18O + 5.36‰. Moreover, we showed that under maritime temperature climate influence...

The kinetic isotope effect of hydrogen, deuterium and tritium absorbed and desorbed by titanium

International Nuclear Information System (INIS)

Huang Gang; Cao Xiaohua; Long Xinggui

2008-06-01

p-t curves of hydrogen, deuterium and tritium absorption at 550-750 degree C and desorption at 350-550 degree C by titanium were investigated. The rate constants of absorption and desorption for hydrogen, deuterium and tritium on each temperature are determined and the activation energy values obtained by this analysis are (55.6 ± 2.4) kJ·mol -1 , (110.2 ± 3.0) kJ·mol -1 and (155.5 ± 3.2) kJ·mol -1 for absorption and (27.1±0.4) KJ·mol -1 , (42.3 ± 1.9) kJ·mol -1 and (62.1±1.6) kJ·mol -1 for desorption respectively. The activation energy value of tritium absorption is highest which shows titanium tritiation is hardest. The activation energy value of tritium desorption is highest and it also can prove that titanium tritide is stablest. There are remarkable kinetic hydrogen isotope effects when titanium absorb and desorb hydrogen, deuterium and tritium. (authors)

Deuterium isotope composition of palaeoinfiltration water trapped in speleothems

International Nuclear Information System (INIS)

Rozanski, K.

1987-05-01

Analytical and methodological aspects of combined isotope investigations of carbonate cave deposits are thoroughly discussed in the report. Weight is put on isotope analyses of fluid inclusions (D and 18 O content) extracted from speleothems of known age. Dating was done by the 230 Th/ 234 U ratio method. Isotopic analyses of speleothems originating from European caves allowed some important conclusions to be formulated regarding past climatic and environmental conditions prevailing over the European continent during the last 300,000 yrs: a) δD values of fluid inclusions suggest a remarkable constancy of the heavy-isotope content of European palaeoinfiltration waters recharged during interglacial periods, b) a climate-induced, long-term changes in isotopic composition of precipitation and surface air temperature over Europe can be characterized by the deuterium gradient of ca.1 4 deg./oo/deg. C, c) an apparent constancy of the continental gradient in deuterium content of European palaeoinfiltration waters as judged from the fluid inclusion data suggests that atmospheric circulation over Europe did not undergo substantial changes for at least 300,000 years

Hydrogen, deuterium, and tritium isotope exchange experiments in JET

Energy Technology Data Exchange (ETDEWEB)

Horton, L.D.; Andrew, P.; Bracco, G.; Conroy, S.; Corti, S.; Ehrenberg, J.; Goodall, D.H.J.; Jarvis, O.N.; Lomas, P.; Loughlin, M.; Peacock, A.T.; Saibene, G.; Sadler, G.; Sartori, R.; Stamp, M.F.; Thomas, P.R.; Belle, P. van (JET Joint Untertaking, Abingdon, Oxfordshire (United Kingdom))

1992-12-01

Isotope exchange experiments have been performed in JET using hydrogen, deuterium, and, in the recent preliminary tritium experiment (PTE), tritium. The rate of change-over from one isotope to another involves two quite different time constants. We have modelled this behaviour using a multireservoir model which splits the accessible hydrogenic particles into two groups, each having a different rate of exchange of particles with the plasma. By applying this model to the sequence of discharges during and after the PTE, we can determine the parameters in the model. The resulting fit also gives a good representation of hydrogen/deuterium change-over experiments, indicating that the tritium behaves in the same manner as other hydrogen isotopes, at least as far as recycling is concerned. Discrepancies between the model and the actual measurements of tritium recovery after the PTE lead us to conclude that isotope exchange processes resulting from collisions of molecules with the vessel walls play a significant role in spreading tritrium around the machine. (orig.).

Mechanistic studies on the bovine liver mitochondrial dihydroorotate dehydrogenase using kinetic deuterium isotope effects

International Nuclear Information System (INIS)

Hines, V.; Johnston, M.

1989-01-01

Dihydroorotates deuteriated at both C 5 and C 6 have been prepared and used to probe the mechanism of the bovine liver mitochondrial dihydroorotate dehydrogenase. Primary deuterium isotope effects on k cat are observed with both (6RS)-[5(S)- 2 H]- and (6RS)-[6- 2 H]dihydroorotates (3 and 6, respectively); these effects are maximal at low pH. At pH 6.6, D V = 3.4 for the C 5 -deuteriated dihydroorotate (3), and D V = 2.3 for the C 6 -deuteriated compound (6). The isotope effects approach unity at pH 8.8. Analysis of the pH dependence of the isotope effects on k cat reveals a shift in the rate-determining step of the enzyme mechanism as a function of pH. Dihydroorotate oxidation appears to require general base catalysis; this step is completely rate-determining at low pH and isotopically sensitive. Reduction of the cosubstrate, coenzyme Q 6 , is rate-limiting at high pH and is isotopically insensitive; this step appears to require general acid catalysis. The results of double isotope substitution studies and analysis for substrate isotope exchange with solvent point toward a concerted mechanism for oxidation of dihydroorotate. This finding serves to distinguish further the mammalian dehydrogenase from its parasitic cognate, which catalyzes a stepwise oxidation reaction

Deuterium isotope effects on 13C and 15N chemical shifts of intramolecularly hydrogen-bonded enaminocarbonyl derivatives of Meldrum’s and Tetronic acid

Science.gov (United States)

Ullah, Saif; Zhang, Wei; Hansen, Poul Erik

2010-07-01

Secondary deuterium isotope effects on 13C and 15N nuclear shieldings in a series of cyclic enamino-diesters and enamino-esters and acyclic enaminones and enamino-esters have been examined and analysed using NMR and DFT (B3LYP/6-31G(d,p)) methods. One-dimensional and two-dimensional NMR spectra of enaminocarbonyl and their deuterated analogues were recorded in CDCl 3 and CD 2Cl 2 at variable temperatures and assigned. 1JNH coupling constants for the derivatives of Meldrum's and tetronic acids reveal that they exist at the NH-form. It was demonstrated that deuterium isotope effects, for the hydrogen bonded compounds, due to the deuterium substitution at the nitrogen nucleus lead to large one-bond isotope effects at nitrogen, 1Δ 15N(D), and two-bond isotope effects on carbon nuclei, 2ΔC(ND), respectively. A linear correlations exist between 2ΔC(ND) and 1Δ 15N(D) whereas the correlation with δNH is divided into two. A good agreement between the experimentally observed 2ΔC(ND) and calculated dσ 13C/dR NH was obtained. A very good correlation between calculated NH bond lengths and observed NH chemical shifts is found. The observed isotope effects are shown to depend strongly on Resonance Assisted Hydrogen bonding.

New NMR method for measuring the difference between corresponding proton and deuterium chemical shifts: isotope effects on exchange equilibria

International Nuclear Information System (INIS)

Saunders, M.; Saunders, S.; Johnson, C.A.

1984-01-01

A convenient and accurate method is described for measuring the difference between a proton frequency and the corresponding deuterium frequency in its deuterated analogue relative to a reference system by using the deuterium lock in a Fourier-transform NMR spectrometer. This measurement is a sensitive way of measuring equilibrium isotope effects for hydrogen-deuterium exchange. A value of 1.60 per H-D pair is obtained for the equilibrium 2H 3 O + + 3D 2 O in equilibrium 2D 3 O + + 3H 2 O at 30 0 C in aqueous perchloric acid (HClO 4 ). 7 references, 2 tables

The study of the deuterium isotopic fractionation through the cell membrane of the plant

International Nuclear Information System (INIS)

Berdea, P.; Cuna, Stela; Deliu, C.

2002-01-01

The purpose of this study is to prove that there is a water deuterium isotope fractionation when the water passes through the cell membrane. The carrots (Daucus carota) were grown in vitro in a Murashige and Skoog mineral-salt medium and have been exposed to a water solution with a uniform isotopic content. After seven days the cell culture was filtered and the cell water was vacuum extracted. The water from aqueous solution and the cell water were analyzed for hydrogen by isotope ratio mass spectrometry. The procedure was repeated for 14 and 21 day old cell cultures. The measurements have revealed a water deuterium isotopic fractionation between extra-cellular water and cellular water. The deuterium content was found to be higher within the cells by 10 o / oo for non-embryonic cells and 13 o / oo for the embryonic cells. This fractionation is a non-evaporative fractionation between intracellular and extra-cellular water and it represents a new step in the overall fractionation of deuterium water in the plants. The existence of such isotopic fractionation through the cell membrane implies that the relationship between the deuterium content of cellulose nitrate in plant and meteoric water should be revised. Also, this finding is of interest for understanding the balance and dynamics of the hydrogen isotopes in the environment. (authors)

Deuterium isotope separation

International Nuclear Information System (INIS)

Benson, S.W.

1979-01-01

Deuterium-containing molecules are separated and enriched by exposing commercially available ethylene, vinyl chloride, 1,2-dichloroethane or propylene to the radiation of tuned infrared lasers to selectively decompose these compounds into enriched molecular products containing deuterium atoms. The deuterium containing molecules can be easily separated from the starting material by absorption, distillation or other simple chemical separation techniques and methods. After evaporation such deuterium containing molecules can be burned to form water with an enriched deuterium content or pyrolyzed to form hydrogen gas with an enriched deuterium content. (author)

Secondary isotope effects on alpha-cleavage reactions

International Nuclear Information System (INIS)

Ingemann, S.; Hammerum, S.

1980-01-01

Kinetic deuterium isotope effects on mass spectral reactions have in several instances been utilized to provide structural information and to answer mechanistic questions. Typically, the influence of the deuterium label on the rate of one of a number of competing reactions has been studied. Secondary isotope effects have usually been assumed to be relatively insignificant in comparison with the observed kinetic effects, even though various workers have shown that secondary isotope effects may indeed exert a considerable influence on the rates of competing simple cleavages. Recent studies have provided quantitative data to show that the mere presence of deuterium atoms up to six bonds away may influence the rate of a simple cleavage reaction. In relation to an investigation of rearrangements accompanying simple cleavage reactions, a semi-quantitative measure was needed of the variation of the secondary isotope effect with the number of bonds between the deuterium label and the point of rupture. The influence has therefore been examined of the presence of remote deuterium atoms on a typical simple cleavage reaction, the α-cleavage of aliphatic amines. As a model compound, N-methyldipentylamine was chosen, systematically labelled with deuterium. (author)

Mechanism and activation for allosteric adenosine 5'-monophosphate nucleosidase. Kinetic alpha-deuterium isotope effects for the enzyme-catalyzed hydrolysis of adenosine 5'-monophosphate and nicotinamide mononucleotide

International Nuclear Information System (INIS)

Skoog, M.T.

1986-01-01

The kinetic alpha-deuterium isotope effect on Vmax/Km for hydrolysis of NMN catalyzed by AMP nucleosidase at saturating concentrations of the allosteric activator MgATP2- is kH/kD = 1.155 +/- 0.012. This value is close to that reported previously for the nonenzymatic hydrolysis of nucleosides of related structure, suggesting that the full intrinsic isotope effect for enzymatic NMN hydrolysis is expressed under these conditions; that is, bond-changing reactions are largely or completely rate-determining and the transition state has marked oxocarbonium ion character. The kinetic alpha-deuterium isotope effect for this reaction is unchanged when deuterium oxide replaces water as solvent, corroborating this conclusion. Furthermore, this isotope effect is independent of pH over the range 6.95-9.25, for which values of Vmax/Km change by a factor of 90, suggesting that the isotope-sensitive and pH-sensitive steps for AMP-nucleosidase-catalyzed NMN hydrolysis are the same. Values of kH/kD for AMP nucleosidase-catalyzed hydrolysis of NMN decrease with decreasing saturation of enzyme with MgATP2- and reach unity when the enzyme is less than half-saturated with this activator. This requires that the rate-determining step changes from cleavage of the covalent C-N bond to one which is isotope-independent. In contrast to the case for NMN hydrolysis, AMP nucleosidase-catalyzed hydrolysis of AMP at saturating concentrations of MgATP2- shows a kinetic alpha-deuterium isotope effect of unity. Thus, covalent bond-changing reactions are largely or completely rate-determining for hydrolysis of a poor substrate, NMN, but make little or no contribution to rate-determining step for hydrolysis of a good substrate, AMP, by maximally activated enzyme. This behavior has several precedents

Mechanism of the reaction catalyzed by dihydrofolate reductase from Escherichia coli: pH and deuterium isotope effects with NADPH as the variable substrate

International Nuclear Information System (INIS)

Morrison, J.F.; Stone, S.R.

1988-01-01

The variations with pH of the kinetic parameters and primary deuterium isotope effects for the reaction of NADPH with dihydrofolate reductase from Escherichia coli have been determined. The aims of the investigations were to elucidate the chemical mechanism of the reaction and to obtain information about the location of the rate-limiting steps. The V and V/K/sub NADPH/ profiles indicate that a single ionizing group at the active center of the enzyme must be protonated for catalysis, whereas the K/sub i/ profiles show that the binding of NADPH to the free enzyme and of ATP-ribose to the enzyme-dihydrofolate complex is pH independent. From the results of deuterium isotope effects on V/K/sub NADPH/, it is concluded that NADPH behaves as a sticky substrate. It is this stickiness that raises artificially the intrinsic pK value of 6.4 for the Asp-27 residue of the enzyme-dihydrofolate complex to an observed value of 8.9. Thus, the binary enzyme complex is largely protonated at neutral pH. The elevation of the intrinsic pK value of 6.4 for the ternary enzyme-NADPH-dihydrofolate complex to 8.5 is not due to the kinetic effects of substrates. Rather, it is the consequence of the lower, pH-independent rate of product release and the faster pH-dependent catalytic step. The data for deuterium isotope and deuterium solvent isotope effects are consistent with the postulate that, for the reduction of dihydrofolate to tetrahydrofolate, protonation precedes hydride transfer. A scheme is proposed for the indirect transfer of a proton from the enzyme to dihydrofolate

Isotope effects in the diffusion of hydrogen and deuterium in ferromagnetic binary alloys of the Cu3Au type

International Nuclear Information System (INIS)

Hirscher, M.; Maier, C.U.; Schwendemann, B.; Kronmueller, H.

1989-01-01

The diffusion behaviour of hydrogen and deuterium at low temperatures was investigated in ordered and disordered alloys of Ni 3 Fe, Ni 3 Mn, and Fe 3 Pt by means of magnetic after-effect (MAE) measurements. After hydrogen charging all specimens show characteristic MAE relaxation spectra, which can be described taking into account the different octahedral positions of the hydrogen atoms in the Cu 3 Au structure. The observed isotope effect can qualitatively be explained by a thermally activated tunnelling process of the hydrogen isotopes. (orig.)

Isotope effects on nuclear shielding

International Nuclear Information System (INIS)

Hansen, P.E.

1983-01-01

This review concentrates upon empirical trends and practical uses of mostly secondary isotope effects, both of the intrinsic and equilibrium types. The text and the tables are arranged in the following fashion. The most 'popular' isotope effect is treated first, deuterium isotope effects on 13 C nuclear shielding, followed by deuterium on 1 H nuclear shieldings, etc. Focus is thus on the isotopes producing the effect rather than on the nuclei suffering the effect. After a brief treatment of each type of isotope effect, general trends are dealt with. Basic trends of intrinsic isotope effects such as additivity, solvent effects, temperature effects, steric effects, substituent effects and hyperconjugation are discussed. Uses of isotope effects for assignment purposes, in stereochemical studies, in hydrogen bonding and in isotopic tracer studies are dealt with. Kinetic studies, especially of phosphates, are frequently performed by utilizing isotope effects. In addition, equilibrium isotope effects are treated in great detail as these are felt to be new and very important and may lead to new uses of isotope effects. Techniques used to obtain isotope effects are briefly surveyed at the end of the chapter. (author)

Absolute measurement of the isotopic ratio of a water sample with very low deuterium content

International Nuclear Information System (INIS)

Hagemann, R.; Nief, G.; Roth, E.

1968-01-01

The presence of H 3+ ions which are indistinguishable from HD + ions presents the principal difficulty encountered in the measurement of isotopic ratios of water samples with very low deuterium contents using a mass spectrometer. Thus, when the sample contains no deuterium, the mass spectrometer does not indicate zero. By producing, in situ, from the sample to be measured, water vapor with an isotopic ratio very close to zero using a small distilling column, this difficulty is overcome. This column, its operating parameters, as well as the way in which the measurements are made are described. An arrangement is employed in which the isotopic ratios can be measured with a sensitivity better than 0.01 x 10 -6 . The method is applied to the determination of the isotopic ratios of three low deuterium content water samples. The results obtained permit one to assign to the sample with the lowest deuterium content an absolute value equal to 1.71 ± 0.03 ppm. This water sample is a primary standard from which is determined the isotopic ratio of a natural water sample which serves as the laboratory standard. (author) [fr

Improvement in deuterium recovery from water–isotope mixture by thermal diffusion in the device of branch columns

International Nuclear Information System (INIS)

Hsu, Ching-Chun; Yeh, Ho-Ming

2014-01-01

Highlights: • Recovery of deuterium by thermal diffusion from water–isotope mixture has been investigated. • The undesirable remixing effect can be reduced by employing the device of branch columns. • Deuterium recoveries were compared with that in a single column of the same total column length. • Considerable recovery improvement is obtainable in the device of branch columns, instead of in a single-column device. - Abstract: Deuterium recovery from water–isotopes mixture using thermal diffusion can be improved by employing the branch column device, instead of single column devices, with the same total column length. The remixing effect due to convection currents in a thermal diffusion column for heavy water enrichment is thus reduced and separation improvement increases when the flow rate or the total column length increases. The improvement in separation can reach about 50% for the numerical example given

Novel PEFC Application for Deuterium Isotope Separation

Directory of Open Access Journals (Sweden)

Hisayoshi Matsushima

2017-03-01

Full Text Available The use of a polymer electrolyte fuel cell (PEFC with a Nafion membrane for isotopic separation of deuterium (D was investigated. Mass analysis at the cathode side indicated that D diffused through the membrane and participated in an isotope exchange reaction. The exchange of D with protium (H in H2O was facilitated by a Pt catalyst. The anodic data showed that the separation efficiency was dependent on the D concentration in the source gas, whereby the water produced during the operation of the PEFC was more enriched in D as the D concentration of the source gas was increased.

Deuterium and heavy water

International Nuclear Information System (INIS)

Vasaru, G.; Ursu, D.; Mihaila, A.; Szentgyorgyi, P.

1975-01-01

This bibliography on deuterium and heavy water contains 3763 references (1932-1974) from 43 sources of information. An author index and a subject index are given. The latter contains a list of 136 subjects, arranged in 13 main topics: abundance of deuterium , catalysts, catalytic exchange, chemical equilibria, chemical kinetics, deuterium and heavy water analysis, deuterium and heavy water properties, deuterium and heavy water separation, exchange reactions, general review, heavy water as moderator, isotope effects, synthesis of deuterium compounds

Biological effects of deuterium - depleted water

International Nuclear Information System (INIS)

Stefanescu, I.; Titescu, Gh.; Croitoru, Cornelia; Saros-Rogobete, Irina

2000-01-01

Deuterium-depleted water (DDW) is represented by water that has an isotopic content smaller than 145 ppm D/(D + H). DDW production technique consists in the separation of deuterium from water by a continuous distillation process under pressure of about 133.3 mbar. The water used as raw material has a isotopic content of 145 ppm D/(D + H) and can be demineralized water, distillated water or condensed-steam. DDW results as a distillate with an isotopic deuterium content of 15-80 ppm, depending on the level we want to achieve. Beginning with 1996 the Institute of Cryogenics and Isotopic Technologies, DDW producer, co-operated with Romanian specialized institutes for studying the biological effects of DDW. The role of naturally occurring D in living organisms was examined by using DDW instead of natural water. These investigations led to the following conclusions: - DDW caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tone and vascular reactivity produced by the DDW persists after the removal of the vascular endothelium; - Animals treated with DDW showed an increase of the resistance both to sublethal and lethal gamma radiation doses, suggesting a radioprotective action by the stimulation of non-specific immune defense mechanisms; - DDW stimulates immuno-defense reactions represented by the opsonic, bactericidal and phagocyte capacity of the immune system together with an increase in the number of poly-morphonuclear neutrophils; - Investigations regarding artificial reproduction of fish with DDW fecundated solutions confirmed favorable influence in embryo growth stage and resistance and following growth stages; - It was studied germination, growth and quantitative character variability in plants; one can remark the favorable influence of DDW on biological processes in plants in various ontogenetic stages. (authors)

Deuterium-depleted water

International Nuclear Information System (INIS)

Stefanescu, Ion; Steflea, Dumitru; Saros-Rogobete, Irina; Titescu, Gheorghe; Tamaian, Radu

2001-01-01

Deuterium-depleted water represents water that has an isotopic content smaller than 145 ppm D/(D+H) which is the natural isotopic content of water. Deuterium depleted water is produced by vacuum distillation in columns equipped with structured packing made from phosphor bronze or stainless steel. Deuterium-depleted water, the production technique and structured packing are patents of National Institute of Research - Development for Cryogenics and Isotopic Technologies at Rm. Valcea. Researches made in the last few years showed the deuterium-depleted water is a biological active product that could have many applications in medicine and agriculture. (authors)

Deuterium isotopic effects connected with unimolecular and concerted mechanisms. The case of 1-deutero-2-chloro alcohols

International Nuclear Information System (INIS)

Jambon, C.

1962-01-01

After a bibliographic analysis of the probable causes of isotopic effects and their comparison, with the simplifications provided by the athermal model, a discussion of the isotopic effect of deuterium in organic molecules in terms of structural influences is presented, showing the important role of the C-D bond length which is shorter than the C-H bond length, and of the D atom's Van der Waals radius, shorter than that of the H atom. Kinetic measurements were carried out on some reactions involving the mechanisms proposed: unimolecular ionizations and halogen concentrates. The structural models chosen are: 2-chloro-cyclo-hexanols cis and trans 1-H and 2-D; 2-chloro-cyclo-pentanols cis trans 1-H and 1-D; 1-phenyl-l-chloro-2-propanol threo 2-H and 2-D. (author) [fr

Computational study of substrate isotope effect probes of transition state structure for acetylcholinesterase catalysis

International Nuclear Information System (INIS)

Sikorski, R.S.; Malany, S.; Seravalli, J.; Quinn, D.M.

2002-01-01

Secondary isotope effects for carbonyl addition reactions of methyl thioacetate, acetone and acetaldehyde have been calculated by ab initio quantum mechanical methods in an effect to interpret measured β-deuterium isotope effects on acetylcholinesterase-catalysed hydrolysis of acetylthiocholine. The calculated β-deuterium isotope effect for equilibrium addition of methanol to methyl thioacetate is D3 K eq = 0.965, and the corresponding effect for addition of methoxide ion to methyl thioacetate wherein three waters are hydrogen bonded to the carbonyl oxyanion is D3 K eq = 1.086. Neither of these calculated isotope effects is an inverse as the experimental β-deuterium isotope effect for acetylcholinesterase-catalysed hydrolysis of acetylthiocholine, D3 K eq = 0.90±0.03. Structural comparisons show that the water-solvated methoxide adduct of methyl thioacetate is more expanded than is the natural methanol addition adduct, and suggest that the degree of which the isotope effect is inverse (i.e. less than) is inversely correlated to the degree of expansion of the adduct. A similar correlation of α-deuterium and β-deuterium secondary isotope effects with the degree of expansion of the adducts is found for equilibrium additions of methanol and methoxide ion to acetylaldehyde. These computational results suggest that the markedly inverse β-deuterium isotope effect for the acetylcholinesterase reaction arises from enzymatic compression of the transition state. (author)

Considerations related to the deuterium-depleted water isotopic analysis for an industrial production pilot plant

International Nuclear Information System (INIS)

Varlam, Mihai; Steflea, Dumitru; Irimescu, Rodica

2000-01-01

In the last few years, there is a major interest related to the use of Deuterium Depleted Water (DDW) for biological and medical purposes. Therefore, a production installation for DDW was developed and now, it is working in our Institute. The deuterium isotopic concentration for the final product is in the 10 - 40 ppm D / (D + H) range depending on customers' requirements. In order to control and manage the production process and also to validate the final product, a special procedure for deuterium content measurement for DDW by Isotopic Ratio Mass Spectrometry was developed. The main instrumentation is a MAT 250 IRMS with a hydrogen preparation line based on the zinc reduction process. The first concern regarding the analysis procedure for these water samples with very low deuterium concentration has been related to the preparation of an internal standard with a D / (D + H) isotopic value in the measurement range. For this raison, a distinct procedure was developed and applied, so that starting to the well-known VSMOW standard and so, a sequence of 12 samples with decreasing deuterium content was obtained. These samples were measured and 3 / 2 ratio mass signals versus 2 mass signal were plotted and statistically analyzed. Obviously, for each measurement, a H 3+ correction factor was calculated and applied, as a results of an entire statistically elimination procedure and by extrapolation of the linear curve plotted, a value for the primary DDW was determined. Other important problem related to deuterium content determination was to minimize the H 3+ factor correction. As the deuterium content is very low the contribution of this factor to the 3 mass signal becomes very important. Therefore, special operations were developed, considering the behaviour of linear dependence between 3 / 2 mass signal versus 2 mass signal in the lower part. Finally, special attention was given to estimate the lower isotopic concentration analysis limit. (authors)

Partial molar volumes of hydrogen and deuterium in niobium and vanadium

International Nuclear Information System (INIS)

Herro, H.M.

1979-01-01

Lattice dilation studies and direct pressure experiments gave comparable values for the partial molar volumes of hydrogen and deuterium in niobium and vanadium. Small isotope effects in the partial molar volume of hydrogen were measured in both metals by the differential isotope method. Hydrogen had a larger partial molar volume than deuterium in niobium, but the reverse was true in vanadium. The isotope effect measured in niobium can be represented as being due to the larger amplitude of vibration of the hydrogen atom than the deuterium atom in the metal lattice. Since hydrogen has a larger mean displacement from the equilibrium position than does deuterium, the average force hydrogen exerts on the metal atoms is greater than the force deuterium exerts. The isotope effect in vanadium is likely a result of anharmonic effects in the lattice and local vibrational modes

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

Science.gov (United States)

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.

Kinetic α secondary deuterium isotope effects for O-ethyl S-phenyl benzaldehyde acetal hydrolysis

International Nuclear Information System (INIS)

Ferraz, J.P.; Cordes, E.H.

1979-01-01

The rate of hydrolysis of O-ethyl S-phenyl benzaldehyde acetal at 25 0 C in 20% dioxane--80% water is independent of pH over the range pH6-12; k/sub obsd/ = 1.9 x 10 -7 s -1 . Under more acidic conditions, the rate increases linearly with the activity of the hydrated proton; k 2 = 2.95 x 10 -2 M -1 s -1 . The kinetic α secondary deuterium isotope effect for acid-catalyzed hydrolysis of O-ethyl S-phenyl benzaldehyde acetal, measured at 25 0 C in 20% aqueous dioxane containing 0.05 M HCl, is k/sub H//k/sub D/ = 1.038 +- 0.008, a value consistent with a transition state in which the C--S bond is stretched rather little. In contrast, the corresponding isotope effect for the pH-independent hydrolysis of this substrate, measured at 42.5 0 C in 20% dioxane, is 1.13 +- 0.02, a value consistent with complete C--S bond cleavage in the transition state and rate-determining diffusion apart of the ion-pair formed as the initial intermediate, in accord with the suggestion of Jensen and Jencks. 1 figure, 4 tables

Quantitative analysis of deuterium using the isotopic effect on quaternary {sup 13}C NMR chemical shifts

Energy Technology Data Exchange (ETDEWEB)

Darwish, Tamim A., E-mail: tamim.darwish@ansto.gov.au [National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Locked Bag 21, Kirrawee DC, NSW 2232 (Australia); Yepuri, Nageshwar Rao; Holden, Peter J. [National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Locked Bag 21, Kirrawee DC, NSW 2232 (Australia); James, Michael [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)

2016-07-13

Quantitative analysis of specifically deuterated compounds can be achieved by a number of conventional methods, such as mass spectroscopy, or by quantifying the residual {sup 1}H NMR signals compared to signals from internal standards. However, site specific quantification using these methods becomes challenging when dealing with non-specifically or randomly deuterated compounds that are produced by metal catalyzed hydrothermal reactions in D{sub 2}O, one of the most convenient deuteration methods. In this study, deuterium-induced NMR isotope shifts of quaternary {sup 13}C resonances neighboring deuterated sites have been utilized to quantify the degree of isotope labeling of molecular sites in non-specifically deuterated molecules. By probing {sup 13}C NMR signals while decoupling both proton and deuterium nuclei, it is possible to resolve {sup 13}C resonances of the different isotopologues based on the isotopic shifts and the degree of deuteration of the carbon atoms. We demonstrate that in different isotopologues, the same quaternary carbon, neighboring partially deuterated carbon atoms, are affected to an equal extent by relaxation. Decoupling both nuclei ({sup 1}H, {sup 2}H) resolves closely separated quaternary {sup 13}C signals of the different isotopologues, and allows their accurate integration and quantification under short relaxation delays (D1 = 1 s) and hence fast accumulative spectral acquisition. We have performed a number of approaches to quantify the deuterium content at different specific sites to demonstrate a convenient and generic analysis method for use in randomly deuterated molecules, or in cases of specifically deuterated molecules where back-exchange processes may take place during work up. - Graphical abstract: The relative intensities of quaternary {sup 13}C {"1H,"2H} resonances are equal despite the different relaxation delays, allowing the relative abundance of the different deuterated isotopologues to be calculated using NMR fast

Secondary. cap alpha. -deuterium kinetic isotope effects in solvolyses of ferrocenylmethyl acetate and benzoate in ethanol

Energy Technology Data Exchange (ETDEWEB)

Sutic, D. (Univ. of Zagreb, Yugoslavia); Asperger, S.; Borcic, S.

1982-12-17

Secondary ..cap alpha..-deuterium kinetic isotope effects (KIE) in solvolyses of ferrocenyldideuteriomethyl acetate and benzoate were determined in 96% (v/v) ethanol, at 25/sup 0/C, as k/sub H//k/sub D/ = 1.24 and 1.26, respectively. The KIEs were also determined in the presence of 0.1 mol dm/sup -3/ lithium perchlorate: the k/sub H//k/ sub D/ values were 1.23 and 1.22 for acetate and benzoate complexes, respectively. The maximum KIE for the C-O bond cleavage of a primary substrate is as large as, or larger than, that of secondary derivatives, which is estimated to be 1.23 per deuterium. The measured KIE of about 12% per D therefore represents a strongly reduced effect relative to its maximum. The solvolyses exhibit ''a special salt effect''. This effect indicates the presence of solvent-separated ion pairs and the return to tight pairs. As the maximum KIE is expected in solvolyses involving transformation of one type of ion pair into another, the strongly reduced ..cap alpha..-D KIE supports the structure involving direct participation of electrons that in the ground state are localized at the iron atom. The alkyl-oxygen cleavage is accompanied by 10-15% acyl-oxygen cleavage.

Isotope effects: definitions and consequences for pharmacologic studies

International Nuclear Information System (INIS)

Van Langenhove, A.

1986-01-01

The use of stable isotope-labeled compounds for pharmacologic studies requires careful consideration of the nature of the stable isotope label (2H, 13C, 15N, 18O) and its position of incorporation in the molecule. When deuterium is used, improper positioning can lead to significant primary isotope effects. Primary isotope effects occur when the breaking of the bond to the heavy isotope is the rate-limiting step in a reaction (or metabolic transformation). A reaction will proceed slower for the molecule with the heavy isotope label because of the mass difference between the light and the heavy isotope. In addition to these primary isotope effects, smaller but nevertheless important secondary isotope effects, physicochemical isotope effects, active hydrogen/deuterium exchange, or isotope effects associated with either the enzyme-catalyzed biotransformation or the mass spectrometric ionization and fragmentation can be operative. In mechanistic studies, isotope effects are used to their advantage; however, in pharmacokinetic studies, the occurrence of isotope effects can lead to grossly misleading biologic and analytic results: the metabolism of the drug will differ when in vivo isotope effects are operative, and isotope effects occurring during the analysis procedure will obscure the true metabolic profile of the drug

Saturation and isotopic replacement of deuterium in low-Z material

International Nuclear Information System (INIS)

Doyle, B.L.; Wampler, W.R.; Brice, D.K.; Picraux, S.T.

1980-01-01

The saturation and replacement of hydrogen isotopes implanted into TiC, TiB 2 , VB 2 , B 4 C, B, Si, and C has been examined experimentally and modeled theoretically. The deuterium saturation concentrations for these materials varied from .16 to .57. A new isotopic replacement model is presented which predicts isotopic trapping and exchange on the basis of the depth dependence of the implanted ions and the experimentally determined hydrogen saturation concentration. Our results indicate that, for these materials used as coatings on components in a D-T fueled tokamak, T recovery by ion induced replacement with H or D should be feasible and that T buildup will be at tolerable levels

Effect of deposited tungsten on deuterium accumulation in beryllium in contact with atomic deuterium

Energy Technology Data Exchange (ETDEWEB)

Sharapov, V.M.; Gavrilov, L.E. [Institute of Physical Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Kulikauskas, V.S.

1998-01-01

Usually ion or plasma beam is used for the experiment with beryllium which simulates the interaction of plasma with first wall in fusion devices. However, the use of thermal or subthermal atoms of hydrogen isotopes seems to be useful for that purpose. Recently, the authors have studied the deuterium accumulation in beryllium in contact with atomic deuterium. The experimental setup is shown, and is explained. By means of elastic recoil detection (ERD) technique, it was shown that in the exposure to D atoms at 740 K, deuterium is distributed deeply into the bulk, and is accumulated up to higher concentration than the case of the exposure to molecular deuterium. The depth and concentration of deuterium distribution depend on the exposure time, and those data are shown. During the exposure to atomic deuterium, oxide film grew on the side of a sample facing plasma. In order to understand the mechanism of deuterium trapping, the experiment was performed using secondary ion mass spectrometry (SIMS) and residual gas analysis (RGA). The influence that the tungsten deposit from the heated cathode exerted to the deuterium accumulation in beryllium in contact with atomic deuterium was investigated. These results are reported. (K.I.)

Rate-controlling two-proton transfer coupled with heavy-atom motion in the 2-pyridinone-catalyzed mutarotation of tetramethylglucose. Experimental and calculated deuterium isotope effects

International Nuclear Information System (INIS)

Engdahl, K.A.; Bivehed, H.; Ahlberg, P.; Saunders, W.H. Jr.

1983-01-01

Primary and secondary deuterium isotope effects have been measured by polarimetry, and primary isotope effects have been calculated for the classical bifunctional catalysis: 2-pyridinone-catalyzed mutarotation of 2,3,4,6-tetra-O-methyl-α-D-glucopyranose (α-TMG) in benzene. From the positively curved plot of the specific rate of epimerization vs. the mole fraction of 2 H in the ''pool'' of OH and NH hydrogens, the isotope effects k/sub HH//k/sub DD/ = 3.66 +/- 0.09, k/sub HH//k/sub DH/ = 1.5, and k/sub HH//k/sub HD/ = 2.4 have been calculated. A secondary isotope effect of 1.14 +/- 0.02 has been measured by using α-TMG and (1- 2 H)-2,3,4,6-tetra-O-methyl-α-D-glucopyranose [(l- 2 H)-α-TMG], the synthesis of which is described in detail, together with those for (N- 2 H)-2-pyridinone and (1-O- 2 H)-2,3,4,6-tetra-O-methyl-α-D-glucopyranose [(1-O- 2 H)-α-TMG]. The rate data obtained have also been analyzed by fractionation theory, yielding approximately equal fractionation factors (0.5). The interpretation of the results has been assisted by calculations of the primary deuterium isotope effects using the BEBOVIB IV program. Two models involving small and considerable coupling, respectively, of the transferring protons to heavy-atom motion have been considered. In the favored structure for the transition state of the rate-limiting step, two protons are in transit, and their motion is governed either by a potential with a barrier or by one without. Their motion is considerably coupled to the heavy-atom motion (i.e., the breakage of the ring C-O bond), and tunnel corrections to the isotope effects are found to be negligible

Water containing deuterium electrolysis to obtain gaseous hydrogen isotope in a high state of purity

International Nuclear Information System (INIS)

Bellanger, Gilbert

1992-01-01

In this paper, the basic concept is to prepare hydrogen in a high state of purity by electrolysing water using a palladium cathode. During electrolysis, hydrogen is at first adsorbed at the palladium surface, and next it diffuses through it till opposite face of its entry where it is desorbed; thus permitting to regain it in a very pure state for storage. The method can be used from water containing deuterium. To improve hydrogen adsorption, surface effect of palladium must be studied. It was found that heat treatment of palladium improved the hydrogen permeation flux. The diffusivity of hydrogen is controlled by Fick and Sieverts equations in which temperature has a significant influence on permeation rates. Anyway, hydrogen desorption does not cause any difficulty. In a second part, we have studied the isotopic separation factor using water containing deuterium. We remarked in fact that it depends on current density, overpotential, diffusivity of hydrogen and deuterium and isotopic composition of electrolyte as expected. In the last part, we realized an original electrolysis model in a glove-box in which are taken into account the results given before and also the technology components employed in processes involving the use of tritium. (author) [fr

Use of azeotropic distillation for isotopic analysis of deuterium in soil water and saturate saline solution

International Nuclear Information System (INIS)

Santos, Antonio Vieira dos.

1995-05-01

The azeotropic distillation technique was adapted to extract soil water and saturate saline solution, which is similar to the sea water for the Isotopic Determination of Deuterium (D). A soil test was used to determine the precision and the nature of the methodology to extract soil water for stable isotopic analysis, using the azeotropic distillation and comparing with traditional methodology of heating under vacuum. This methodology has been very useful for several kinds of soil or saturate saline solution. The apparatus does not have a memory effect, and the chemical reagents do not affect the isotopic composition of soil water. (author). 43 refs., 10 figs., 12 tabs

Deuterium-depleted water. Romanian achievements and perspective

International Nuclear Information System (INIS)

Stefanescu, Ion; Saros-Rogobete, Irina; Titescu, Gheorghe

2001-01-01

Deuterium-depleted water has an isotopic content smaller than 145 ppm D/(D+H) which is the natural isotopic content of water. Beginning with 1996 ICSI Rm. Valcea, deuterium-depleted water producer, co-operated with Romanian specialized institutes for biological effect's evaluation of deuterium-depleted water. These investigations lead to the following conclusions: - Deuterium-depleted water caused a tendency towards the increase of the basal tonus, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tonus and vascular reactivity produced by the deuterium-depleted water persist after the removal of the vascular endothelium; - Animals treated with deuterium-depleted water showed an increase of the resistance both to sublethal and to lethal gamma radiation doses, suggesting a radioprotective action; - Deuterium-depleted water stimulates immune defence reactions and increases the numbers of polymorphonuclear neutrophils; - Investigations regarding artificial reproduction of fish with deuterium-depleted water fecundated solutions confirmed favourable influence in embryo growth stage and resistance in subsequent growth stages; - It was studied germination, growth and quantitative character's variability in plants; one can remark the favourable influence of deuterium-depleted water on biological process in plants in various ontogenetic stages; - The deuterium depletion in seawater produces the diminution of the water spectral energy related to an increased metabolism of Tetraselmis Suecica. (authors)

Isotopic scaling of transport in deuterium-tritium plasmas

International Nuclear Information System (INIS)

Scott, S.D.; Adler, H.; Bell, M.G.; Bell, R.; Budny, R.V.; Bush, C.E.; Chang, Z.; Duong, H.

1995-01-01

Both global and thermal energy confinement improve in high-temperature supershot plasmas in the Tokamak Fusion Test Reactor (TFTR) when deuterium beam heating is partially or wholly replaced by tritium beam heating. For the same heating power, the tritium-rich plasmas obtain up to 22% higher total energy, 30% higher thermal ion energy, and 20-25% higher central ion temperature. Kinetic analysis of the temperature and density profiles indicates a favorable isotopic scaling of ion heat transport and electron particle transport, with τ Ei (a/2) ∝ (A) 0.7-0.8 and τ pe (a) ∝ (A) 0.8

Combining Solvent Isotope Effects with Substrate Isotope Effects in Mechanistic Studies of Alcohol and Amine Oxidation by Enzymes*

Science.gov (United States)

Fitzpatrick, Paul F.

2014-01-01

Oxidation of alcohols and amines is catalyzed by multiple families of flavin-and pyridine nucleotide-dependent enzymes. Measurement of solvent isotope effects provides a unique mechanistic probe of the timing of the cleavage of the OH and NH bonds, necessary information for a complete description of the catalytic mechanism. The inherent ambiguities in interpretation of solvent isotope effects can be significantly decreased if isotope effects arising from isotopically labeled substrates are measured in combination with solvent isotope effects. The application of combined solvent and substrate (mainly deuterium) isotope effects to multiple enzymes is described here to illustrate the range of mechanistic insights that such an approach can provide. PMID:25448013

Deuterium isotope separation factor between hydrogen and liquid water

International Nuclear Information System (INIS)

Rolston, J.H.; den Hartog, J.; Butler, J.P.

1976-01-01

The overall deuterium isotope separation factor between hydrogen and liquid water, α, has been measured directly for the first time between 280 and 370 0 K. The data are in good agreement with values of α calculated from literature data on the equilibrium constant for isotopic exchange between hydrogen and water vapor, K 1 , and the liquid-vapor separation factor, α/sub V/. The temperature dependence of α over the range 273-473 0 K based upon these new experimental results and existing literature data is given by the equation ln α = -0.2143 + (368.9/T) + (27,870/T 2 ). Measurements on α/sub V/ given in the literature have been surveyed and the results are summarized over the same temperature range by the equation ln α/sub V/ = 0.0592 - (80.3/T) +

H/D isotope effects in high temperature proton conductors

DEFF Research Database (Denmark)

Bonanos, Nikolaos; Huijser, A.; Poulsen, Finn Willy

2015-01-01

The atomic mass ratio of ca. 2 between deuterium and hydrogen is the highest for any pair of stable isotopes and results in significant and measurable H/D isotope effects in high temperature proton conductors containing these species. This paper discusses H/D isotope effects manifested in O-H/O-D...

Inter- and intramolecular deuterium isotope effects on the cytochrome P-450-catalyzed oxidative dehalogenation of 1,1,2,2-tetrachloroethane

International Nuclear Information System (INIS)

Hales, D.B.; Ho, B.; Thompson, J.A.

1987-01-01

The oxidation of 1,1,2,2-tetrachloroethane to dichloroacetic acid was investigated with rat liver microsomes and purified cytochrome P-450. Deuterium substitution had no effect on Km values, but both the inter- and intramolecular isotope effects (kH/kD) on Vmax were in the range 5.7-6.1. The equivalence of the inter- and intramolecular values indicates that 6.0 may be a good estimate of the intrinsic isotope effect. The intermolecular kH/kD value for the conversion of 1,1,2,2-trichloroethane and its 1- 2 H analog to chloroacetic acid was 5.5. These data, and the finding that 1 atom of 18 O was incorporated into the product when TCEA was oxidized in an 18 O 2 atmosphere, support an oxidative dechlorination mechanism that involves hydrogen atom abstraction by the P-450 intermediate oxo complex

Effects of must concentration techniques on wine isotopic parameters.

Science.gov (United States)

Guyon, Francois; Douet, Christine; Colas, Sebastien; Salagoïty, Marie-Hélène; Medina, Bernard

2006-12-27

Despite the robustness of isotopic methods applied in the field of wine control, isotopic values can be slightly influenced by enological practices. For this reason, must concentration technique effects on wine isotopic parameters were studied. The two studied concentration techniques were reverse osmosis (RO) and high-vacuum evaporation (HVE). Samples (must and extracted water) have been collected in various French vineyards. Musts were microfermented at the laboratory, and isotope parameters were determined on the obtained wine. Deuterium and carbon-13 isotope ratios were studied on distilled ethanol by nuclear magnetic resonance (NMR) and isotope ratio mass spectrometry (IRMS), respectively. The oxygen-18 ratio was determined on extracted and wine water using IRMS apparatus. The study showed that the RO technique has a very low effect on isotopic parameters, indicating that this concentration technique does not create any isotopic fractionation, neither at sugar level nor at water level. The effect is notable for must submitted to HVE concentration: water evaporation leads to a modification of the oxygen-18 ratio of the must and, as a consequence, ethanol deuterium concentration is also modified.

Mechanism of the flame ionization detector. II. Isotope effects and heteroatom effects

DEFF Research Database (Denmark)

Holm, Torkil

1997-01-01

The relative molar flame ionization detecton (FID) response (RMR) for a hydrocarbon does not change when deuterium is substituted for hydrogen. The exception is methane for which an inverse deuterium effect of 3..5% is observed for tetradeuteriomethane. [13C]Methane shows an inverse isotope effect...... of 2%. The reason for the small or non-existent isotope effects is that H/2H exchange takes place in the pre-combustion hydrogenolysis in the flame. This was shown by taking samples from the lower part of the flame by means of a fused silica capillary probe. By the same technique the hydrogenolytic...

Method of deuterium isotope separation and enrichment

International Nuclear Information System (INIS)

Benson, S.W.

1978-01-01

A method of separating deuterium, i.e., heavy hydrogen, from certain naturally occurring sources using tuned infrared lasers to selectively decompose specified classes of organic molecules (i.e., RX) into enriched molecular products containing deuterium atoms is described. The deuterium containing molecules are easily separated from the starting material by absorption, distillation or other simple chemical separation techniques and methods. After evaporation such deuterium containing molecules can be burned to form water with an enriched deuterium content or pyrolyzed to form hydrogen gas with an enriched deuterium content. The undecomposed molecules and the other reaction products which are depleted of their deuterium containing species can be catalytically treated, preferably using normal water, to restore the natural abundance of deuterium and such restored molecules can then be recycled

Isotope effects on chemical equilibria

International Nuclear Information System (INIS)

Golding, P.D.

1974-01-01

The thermodynamic equilibrium constants of three deuterated substituted acetic acids are reported. The calculation of secondary isotope effects of the second kind for the three isotopic acid pairs has been accomplished by the appropriate comparison of thermodynamic equilibrium constants, and by the comparison of isotopic slopes. The effect of substituent variation on the isotope effects reported here disqualifies the simple inductive model as a legitimate description of secondary isotope effects of the second kind. The correlation of diminishing isotope effect per deuterium atom with increasing acidity is also invalidated by the present results. The syntheses of 9-thia-9,10-dihydrophenanthrene-9-oxide and thioxanthene-10-oxide are described. These compounds have been partially deuterated at their respective methylene positions. Spectral evidence indicates stereoselectivity of the methylene protons in the exchange reactions of both compounds. (author)

[Solid state isotope hydrogen exchange for deuterium and tritium in human gene-engineered insulin].

Science.gov (United States)

Zolotarev, Yu A; Dadayan, A K; Kozik, V S; Gasanov, E V; Nazimov, I V; Ziganshin, R Kh; Vaskovsky, B V; Murashov, A N; Ksenofontov, A L; Haribin, O N; Nikolaev, E N; Myasoedov, N F

2014-01-01

The reaction of high temperature solid state catalytic isotope exchange in peptides and proteins under the action of catalyst-activated spillover hydrogen was studied. The reaction of human gene-engineered insulin with deuterium and tritium was conducted at 120-140° C to produce insulin samples containing 2-6 hydrogen isotope atoms. To determine the distribution of the isotope label over tritium-labeled insulin's amino acid residues, oxidation of the S-S bonds of insulin by performic acid was performed and polypeptide chains isolated; then their acid hydrolysis, amino acid analysis and liquid scintillation counts of tritium in the amino acids were conducted. The isotope label was shown to be incorporated in all amino acids of the protein, with the peptide fragment FVNQHLCGSHLVE of the insulin β-chain showing the largest incorporation. About 45% of the total protein isotope label was incorporated in His5 and His10 of this fragment. For the analysis of isotope label distribution in labeled insulin's peptide fragments, the recovery of the S-S bonds by mercaptoethanol, the enzymatic hydrolysis by glutamyl endopeptidase from Bacillus intermedius and HPLC division of the resulting peptides were carried out. Attribution of the peptide fragments formed due to hydrolysis at the Glu-X bond in the β-chain was accomplished by mass spectrometry. Mass spectrometry analysis data of the deuterium-labeled insulin samples' isotopomeric composition showed that the studied solid state isotope exchange reaction equally involved all the protein molecules. Biological studying of tritium-labeled insulin showed its physiological activity to be completely retained.

Isotopic scaling of transport in deuterium-tritium plasmas

International Nuclear Information System (INIS)

Scott, S.D.; Murakami, M.; Adler, H.; Chang, Z.; Duong, H.; Grisham, L.R.; Fredrickson, E.D.; Grek, B.; Hawryluk, R.J.; Hill, K.W.; Hosea, J.; Jassby, D.L.; Johnson, D.W.; Johnson, L.C.; Loughlin, M.J.; Mansfield, D.K.; McGuire, K.M.; Meade, D.M.; Mikkelsen, D.M.; Murphy, J.; Park, H.K.; Ramsey, A.T.; Schivell, J.; Skinner, C.H.; Strachan, J.D.; Synakowski, E.J.; Taylor, G.; Thompson, M.E.; Wieland, R.; Zarnstorff, M.C.

1995-01-01

Both global and thermal energy confinement improve in high-temperature supershot plasmas in the Tokamak Fusion Test Reactor (TFTR) when deuterium beam heating is partially or wholly replaced by tritium beam heating. For the same heating power, the tritium-rich plasmas obtain up to 22% higher total energy, 30% higher thermal ion energy, and 20-25% higher central ion temperature. Kinetic analysis of the temperature and density profiles indicates a favorable isotopic scaling of ion heat transport and electron particle transport, with τ Ei (a/2) ∝ left angle A right angle 0.7-0.8 and τ pe (a) ∝ left angle A right angle 0.8 . (orig.)

Secondary deuterium isotope effects for acid-catalyzed hydrolysis of inosine and adenosine

International Nuclear Information System (INIS)

Romero, R.; Stein, R.; Bull, H.G.; Cordes, E.H.

1978-01-01

Kinetic α deuterium isotope effects have been measured for acid-catalyzed hydrolysis of inosine and adenosine. For inosine hydrolysis, values of k/sub H/k/sub D/ follow: in 1.0 M HCl, 1.21 and 1.20 at 25 and 50 0 C, respectively; in 0.1 M HCl, 1.19 and 1.18 at 25 and 50 0 C, respectively. For adenosine hydrolysis, k/sub H/k/sub D/ is 1.23 in 0.1 M HCl at 25 0 C. The values require that the transition states for hydrolysis of both the monocation and dication of inosine and the dication of adenosine have marked oxocarbonium ion character. Detailed mechanisms which accord with this and other experimental observations include (1) a classical Al mechanism in which the C--N bond is largely cleaved in the transition state; (2) a mechanism involving some form of nucleophilic participation by solvent in which bond cleavage is advanced relative to bond formation in the transition state; or (3) complete C--N bond cleavage with rate-determining diffusion apart of oxocarbonium ion and purine base. 53 references, 1 figure, 2 tables

Comparison of total body water determinations in lactating women by anthropometry, water displacement, and deuterium isotope dilution

International Nuclear Information System (INIS)

Wong, W.; Butte, N.; Lee, L.; Garza, C.; Klein, P.

1986-01-01

To expand the limited data on the total body water in lactating women, the authors have determined total body water contents, in eight subjects from anthropometric measurements, water displacement, and isotope dilution of deuterium oxide. On the day of the study, their skinfold thicknesses were measured over the biceps and triceps muscles and at the suprailiac and subscapular areas. Their body densities were measured by water displacement. Deuterium oxide was administered orally at 100 mg/kg of body weight. One predose milk sample was collected from each subject. The milk samples were defatted by centrifugation and the milk water was reduced to hydrogen gas for hydrogen isotope ratio measurements by gas-isotope-ratio mass spectrometry. The results indicated that total body water in lactating women estimated from anthropometric measurements was 49.7 +/- 3.3% of body weight, by water displacement was 54.9 +/- 7.2%, and by isotope dilution was 50.8 +/- 3.7%

Process and device for stage by stage enrichment of deuterium and/or tritium in a material suitable for isotope exchange of deuterium and tritium with hydrogen

International Nuclear Information System (INIS)

Iniotakis, N.; Decken, C.B. von der.

1983-01-01

Water containing deuterium and/or tritium is first introduced into a carrier gas flow and reduced for the stage by stage enrichment of deuterium and/or tritium. A hydrogen partial pressure of a maximum of 100 millibar is set in the carrier gas flow. The carrier gas flow is taken along the primary side of an exchange wall suitable for the permeation of hydrogen, and a further carrier gas flow flows on its secondary side, which contains water or hydrogen. Reaction products formed after isotope exchange of deuterium and/or tritium with hydrogen are removed by the secondary carrier gas flow. (orig./HP) [de

Catalytic isotope exchange reaction between deuterium gas and water pre-adsorbed on platinum/alumina

International Nuclear Information System (INIS)

Iida, Itsuo; Kato, Junko; Tamaru, Kenzi.

1976-01-01

The catalytic isotope exchange reaction between deuterium gas and the water pre-adsorbed on Pt/Al 2 O 3 was studied. At reaction temperatures above 273 K, the exchange rate was proportional to the deuterium pressure and independent of the amount of adsorbed water, which suggests that the rate determining step is the supply of deuterium from the gas phase. Its apparent activation energy was 38 kJ mol -1 . Below freezing point of water, the kinetic behaviour was different from that above freezing point. At higher deuterium pressures the rate dropped abruptly at 273 K. Below the temperature the apparent activation energy was 54 kJ mol -1 and the exchange rate depended not on the deuterium pressure but on the amount of the pre-adsorbed water. At lower pressures, however, the kinetic behaviour was the same as the above 273 K, till the rate of the supply of deuterium from the gas phase exceeded the supply of hydrogen from adsorbed water to platinum surface. These results suggest that below 273 K the supply of hydrogen is markedly retarded, the state of the adsorbed water differing from that above 273 K. It was also demonstrated that when the adsorbed water is in the state of capillary condensation, the exchange rate becomes very small. (auth.)

Isotope effects in photochemical rearrangements

International Nuclear Information System (INIS)

Sommer, F.

1983-01-01

Taking anthracene resp. 9-deuteroanthracene as the initial substance, different substitution products have been prepared. The products originating by direct photolysis have been characterized and their structure has been determined. By comparing the measured kinetic isotope effect and the quantum yield of the nondeuterated and the monodeuterated fluorenes formed it could been demonstrated that the isotope effect mainly is due to the reaction rates and the influence of the deuterium substitution upon the radiationless desactivation against that is small. (HBR) [de

Traceability of synthetic drugs by position-specific deuterium isotope ratio analysis

Energy Technology Data Exchange (ETDEWEB)

Brenna, Elisabetta [Dipartimento di Chimica, Materiali e di Ingegneria Chimica del Politecnico di Milano and Istituto CNR per la Chimica del Riconoscimento Molecolare, Via Mancinelli 7, Milan I-20131 (Italy)], E-mail: elisabetta.brenna@polimi.it; Fronza, Giovanni [Dipartimento di Chimica, Materiali e di Ingegneria Chimica del Politecnico di Milano (Italy) and Instituto CNR per la Chimica del Riconoscimento Molecolare, Via Mancinelli 7, Milan I-20131 (Italy)], E-mail: giovanni.fronza@polimi.it; Fuganti, Claudio [Dipartimento di Chimica, Materiali e di Ingegneria Chimica del Politecnico di Milano (Italy) and Istituto CNR per la Chimica del Riconoscimento Molecolare, Via Mancinelli 7, Milan I-20131 (Italy)

2007-10-10

Samples of fluoxetine of different origin were submitted to natural abundance {sup 2}H NMR spectroscopy. The deuterium content at the various sites of the molecule was found to depend on its synthetic history. Hints on the synthetic procedure can be obtained by comparison with standard compounds, whose synthesis is known. These preliminary results give an idea of the potential of site-specific isotope ratio analysis in the fight against patent infringement and drug counterfeiting.

Traceability of synthetic drugs by position-specific deuterium isotope ratio analysis

International Nuclear Information System (INIS)

Brenna, Elisabetta; Fronza, Giovanni; Fuganti, Claudio

2007-01-01

Samples of fluoxetine of different origin were submitted to natural abundance 2 H NMR spectroscopy. The deuterium content at the various sites of the molecule was found to depend on its synthetic history. Hints on the synthetic procedure can be obtained by comparison with standard compounds, whose synthesis is known. These preliminary results give an idea of the potential of site-specific isotope ratio analysis in the fight against patent infringement and drug counterfeiting

The H+3 + H2 isotopic system. Origin of deuterium astrochemistry

International Nuclear Information System (INIS)

Hugo, Edouard Jean-Marie

2008-01-01

Dense cold molecular clouds reckoned to be stellar nurseries are the scene of an extreme molecular deuteration. Despite the cosmic D/H ratio of ∝10 -5 , molecular species in prestellar cores are observed to contain nearly as much deuterium as hydrogen. This astonishing deuterium enrichment promoted by low temperatures is the work of H + 3 . It is the key species which unlocks the deuterium from its HD reservoir via reactions like H + 3 +HD ↔ H 2 D + +H 2 and drags it further to other species in successive reactions. For this reason, the H + 3 +H 2 isotopic system is outstandingly critical for the astrochemistry of cold environments. However, its understanding is yet incomplete and insufficient. This thesis thus focuses on the H + 3 +H 2 isotopic system from a theoretical, experimental and astronomical point of view giving a particular look into the role of nuclear spins. As a first step, the stringent nuclear spin selection rules in associative, dissociative and reactive collisions are investigated. This purely theoretical study zooms into the details of the nuclear spin wavefunctions and shows that their permutation symmetry representation is necessary and sufficient, contrary to their angular momentum representation. Additionally, a new deterministic interpretation of nuclear spins in chemical reactions is proposed. Based on these considerations, a complete set of state-to-state rate coefficients for all H + 3 + H 2 isotopic variants is calculated using a microcanonical model leaned on phase space theory. An experimental study is conducted in parallel with a 22-pole ion trap apparatus in order to inspect the influences of temperature and H 2 ortho-to-para ratio. The good overall agreement between experimental and theoretical results supports the validity and utility of the calculated set of rate coefficients. Furthermore, the potentiality of the 22-pole ion trap apparatus is explored via the Laser Induced Reaction (LIR) technique applied to our system of

Method of deuterium isotope separation and enrichment

International Nuclear Information System (INIS)

Benson, S.W.

1979-01-01

A method is described for separating and enriching deuterium containing molecules comprising the steps of: providing a source of organic molecules containing a normal abundance of deuterium atoms, the organic molecules having a structural formula RX, in which R is an organic radical selected from ethyl, isopropyl, t-butyl and 3-cyclopentenyl, and in which X is selected from F, Cl, Br and OH, and wherein R represents 3-cyclopentenyl, X may additionally represent H; exposing the molecules to the radiation of at least one pulsed infrared laser source which has been specifically tuned and focussed to selectively decompose RX molecules containing deuterium to form an enriched olefin specie containing deuterium, and HX; and separating the deuterium enriched olefin specie from the undecomposed deuterium depleted RX molecules and HX. (author)

A general procedure for isotopic (deuterium) labelling of non-steroidal antiinflammatory 2-arylpropionic acids

International Nuclear Information System (INIS)

Castell, J.V.; Martinez, L.A.; Universidad Politecnica de Valencia; Miranda, M.A.; Tarrega, Pilar

1994-01-01

Alkaline treatment of nonsteroidal antiinflammatory 2-arylpropionic acids in deuterium oxide led in all cases to isotopic exchange of the proton located at the α-position of the side chain. Monodeuteration was observed in the case of carprofen, ibuprofen, ketoprofen, fenoprofen, flurbiprofen and naproxen. Additional exchange of one or two protons of the heterocyclic ring occurred in indoprofen, suprofen and tiaprofenic acid. The isotopic labelling survived under the conditions required to perform in vitro photoallergic studies (photolysis in non-deuterated aqueous media). (Author)

A general procedure for isotopic (deuterium) labelling of non-steroidal antiinflammatory 2-arylpropionic acids

Energy Technology Data Exchange (ETDEWEB)

Castell, J.V. (Valencia Univ. Hospital (Spain). Centro de Investigacion); Martinez, L.A. (Valencia Univ. Hospital (Spain). Centro de Investigacion Universidad Politecnica de Valencia (Spain). Dept. de Quimica); Miranda, M.A.; Tarrega, Pilar (Universidad Politecnica de Valencia (Spain). Dept. de Quimica)

1994-01-01

Alkaline treatment of nonsteroidal antiinflammatory 2-arylpropionic acids in deuterium oxide led in all cases to isotopic exchange of the proton located at the [alpha]-position of the side chain. Monodeuteration was observed in the case of carprofen, ibuprofen, ketoprofen, fenoprofen, flurbiprofen and naproxen. Additional exchange of one or two protons of the heterocyclic ring occurred in indoprofen, suprofen and tiaprofenic acid. The isotopic labelling survived under the conditions required to perform in vitro photoallergic studies (photolysis in non-deuterated aqueous media). (Author).

Research of catalysts for isotope enrichment of deuterium oxide in water - PX15-01/89 progress report

International Nuclear Information System (INIS)

1989-08-01

The information about the development of research project for producing concentrate deuterium oxide by isotope enrichment in hydrogen-water contact systems combined with electrolysis are described. (C.G.C.)

Alternate substrates and isotope effects as a probe of the malic enzyme reaction

International Nuclear Information System (INIS)

Gavva, S.R.

1988-01-01

Dissociation constants for alternative dinucleotide substrates and competitive inhibitors suggest that the dinucleotide binding site of the Ascaris suum NAD-malic enzyme is hydrophobic in the vicinity of the nicotinamide ring. Changes in the divalent metal ion activator from Mg 2+ to Mn 2+ or Cd 2+ results in a decrease in the dinucleotide affinity and an increase in the affinity for malate. Primary deuterium and 13 C isotope effects obtained with the different metal ions suggest either a change in the transition state structure for the hydride transfer or decarboxylation steps or both. Deuterium isotope effects are finite whether reactants are maintained at saturating or limiting concentrations with all the metal ions and dinucleotide substrates used. For the native enzyme, primary deuterium isotope effects increase with a concomitant decrease in the 13 C effects when NAD is replaced by an alternate dinucleotide substrate different in redox potential

Detection of a deuterium isotope effect in di- and trisubstituted alkylphenylnitrosoureas. An SCE study in Chinese hamster V79-E cells

International Nuclear Information System (INIS)

Thust, R.; Mendel, J.; Bach, B.; Schwarz, H.

1985-01-01

The genotoxicity of 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (C1-MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU) and their derivatives substituted by deuterium in different positions was studied using sister chromatid exchange (SCE) induction in Chinese hamster V79-E cells. Deuterium substitution in the 1-methyl group of MPNU (MPNU-d3) and C1-MPNU (C1-MPNU-d3) diminished the SCE-inducing capacity by 20-30% and by 30-40% in DMPNU (DMPNU-d3B). There was no altered SCE activity detected when the phenyl group of MPNU (MPNU-d5) or the 3-methyl group of DMPNU (DMPNU-d3A) was deuterium labeled. No isotope effect was detected in deuterated EPNU derivatives, presumably due to the instability of these compounds. It is surmised that the easier delocalization of the positive charge in the deuterated alkyl diazonium ion causes a diminished reactivity and therefore influences the type and amount of DNA alkylation. Furthermore, the experiments with DMPNU and its derivatives revealed that, in contrast to mono- and disubstituted nitrosoureas, the biological activities of these very stable trisubstituted nitrosoureas are strongly influenced by a serum factor in the culture fluid

Detection of a deuterium isotope effect in di- and trisubstituted alkylphenylnitrosoureas. An SCE study in Chinese hamster V79-E cells.

Science.gov (United States)

Thust, R; Mendel, J; Bach, B; Schwarz, H

1985-06-01

The genotoxicity of 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (C1-MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU) and their derivatives substituted by deuterium in different positions was studied using sister chromatid exchange (SCE) induction in Chinese hamster V79-E cells. Deuterium substitution in the 1-methyl group of MPNU (MPNU-d3) and C1-MPNU (C1-MPNU-d3) diminished the SCE-inducing capacity by 20-30% and by 30-40% in DMPNU (DMPNU-d3B). There was no altered SCE activity detected when the phenyl group of MPNU (MPNU-d5) or the 3-methyl group of DMPNU (DMPNU-d3A) was deuterium labeled. No isotope effect was detected in deuterated EPNU derivatives, presumably due to the instability of these compounds. It is surmised that the easier delocalization of the positive charge in the deuterated alkyl diazonium ion causes a diminished reactivity and therefore influences the type and amount of DNA alkylation. Furthermore, the experiments with DMPNU and its derivatives revealed that, in contrast to mono- and disubstituted nitrosoureas, the biological activities of these very stable trisubstituted nitrosoureas are strongly influenced by a serum factor in the culture fluid.

Secondary deuterium isotope effects and transition state structure in the aromatic claisen rearrangement

International Nuclear Information System (INIS)

McMichael, K.D.; Korver, G.L.

1979-01-01

Kinetic experiments were carried out simultaneously on separate methyl salicylate solutions of allyl phenyl ether and its deuterated phenyl analogues at 170 to 195 0 C. Gas chromatographic analysis for allyl phenyl ether using an internal standard (anisole) and mechanical integration produced concentration/time data which were fitted to the exponential form of the first-order rate equation by a standard and nonlinear least-square program. At least 15 points were obtained for each run, covering 10 to 85% reaction. The derived isotope effects show no temperature dependence. Averages for 6 runs with each compound are k/sub H//k/sub α-D 2 / = 1.18 and K/sub H//k/sub γ-D 2 / = 0.95. An equilibrium α effect of 1.30 and a γ effect of 0.87 may be calculated for both deuterium atoms at 185 0 C. These results show that the C--H vibration frequencies are approximately (1.18 - 1)/(1.27 - 1) or 57 to 77% of the way from those of allyl phenyl ether to those of the cyclohexadiene intermediate. The C--H frequencies of the γ carbon in the transition state are about (0.95 - 1)/(0.88 - 1) or 22 to 62% of the way to those of the intermediate. The structure of the transition state, as far as these bonding frequencies are concerned, is consistent with the Claisen rearrangement

Hydrogen/deuterium isotope effects in water and aqueous solutions of organic molecules and proteins

International Nuclear Information System (INIS)

Price, David L.; Fu, Ling; Bermejo, F. Javier; Fernandez-Alonso, Felix; Saboungi, Marie-Louise

2013-01-01

Highlights: ► Hydrogen/deuterium substitution has significant effects in hydrogenous materials. ► The effects can involve structure, phase behavior and protein stability. ► The effects must be kept in mind in the interpretation of scattering experiments. ► The effects may be mitigated by an appropriate choice of experimental conditions. - Abstract: It is pointed out that hydrogen/deuterium substitution, frequently used in neutron scattering studies of the structure and dynamics of hydrogenous samples, can have significant effects on structure, phase behavior and protein stability. The effects must be kept in mind in the interpretation of such experiments. In suitable cases, these effects can be mitigated by an appropriate choice of experimental conditions

Natural abundance deuterium nuclear magnetic resonance spectroscopy: Study of the biosynthesis of monoterpenes

International Nuclear Information System (INIS)

Leopold, M.F.

1990-01-01

Deuterium NMR spectroscopy at natural abundance (D NMR-na) is a new technique for exploring the biosynthesis of small molecules such as monoterpenes. The analysis of relative site-specific deuterium integration values is an effective means of measuring isotope effects, and examining the regio- and stereochemistry of biosynthetic reactions. The deuterium integration values of linalyl acetate and limonene isolated from the same source were consistent and showed that proton abstraction from the postulated α-terpinyl cation intermediate to form limonene is regioselective from the methyl derived from the Cs methyl of the precursor, geranyl diphosphate. This regiochemistry was observed in limonene samples from different sources and the measured primary kinetic isotope effect ranged from 0.25 to in excess of 100 (no deuterium was removed within experimental error). Various α- and β-pinene samples were isolated and D NMR-na analysis showed evidence of isotopically sensitive partitioning of the pinylcation in the formation of these products. This spectral analysis supported published radiolabeling studies but did not require synthesis of substrates or enzyme purification. The formation of 3-carene occurs without isomerization of the double bond which was previously postulated. The olefinic deuterium of the bicyclic compound was traced to the depleted deuterium at C 2 of isopentyl diphosphate by D NMR-na data and this supported unpublished radiolabeling studies. Study of irregular monoterpenes, chrysanthemyl acetate and lyratyl acetate, showed partitioning of dimethylallyl diphosphate (DMAPP) by chrysanthemyl cyclase. The α-secondary kinetic isotope effect of 1.06-1.12, obtained from relative deuterium integration values, suggested that S N 1 ionization of one molecule of DMAPP is the first step in the condensation reaction

Deuterium - depleted water. Achievements and perspectives

International Nuclear Information System (INIS)

Titescu, Gh.; Stefanescu, I.; Saros-Rogobete, I.

2001-01-01

Deuterium - depleted water represents water that has an isotopic content lower than 145 ppm D/(D+H) which is the natural isotopic content of water. The research conducted at ICSI Ramnicu Valcea, regarding deuterium - depleted water were completed by the following patents: - technique and installation for deuterium - depleted water production; - distilled water with low deuterium content; - technique and installation for the production of distilled water with low deuterium content; - mineralized water with low deuterium content and technique to produce it. The gold and silver medals won at international salons for inventions confirmed the novelty of these inventions. Knowing that deuterium content of water has a big influence on living organisms, beginning with 1996, the ICSI Ramnicu Valcea, deuterium - depleted water producer, co-operated with Romanian specialized institutes for biological effects' evaluation of deuterium - depleted water. The role of natural deuterium in living organisms was examined by using deuterium - depleted water instead of natural water. These investigations led to the following conclusions: 1. deuterium - depleted water caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tone and vascular reactivity produced by the deuterium - depleted water persists after the removal of the vascular endothelium; -2. animals treated with deuterium - depleted water showed an increase of the resistance both to sublethal and to lethal gamma radiation doses, suggesting a radioprotective action by the stimulation of non-specific immune defence mechanism; 3, deuterium - depleted water stimulates immune defence reactions, represented by the opsonic, bactericidal and phagocyte capacity of the immune system, together with increase in the numbers of polymorphonuclear neutrophils; 4. investigations regarding artificial

Leakage Identification Of Volcanic Product Pollutant Of ijen Crater Using Natural Isotop Deuterium And Oxiren-18

International Nuclear Information System (INIS)

Susiati, Heni; Sjarmufni, A.; S.B.S, Yarianto; Suprijadi; Wibagyo

2001-01-01

Community surrounding the Asembagus Sugar Fabric guess that the factory has polluted water body of Banyuputih River. Leakage detection of the pollutant has been to prove that guess using variation of natural isotop composition of Deuterium and Oxygen-18. Sampling was carried out at Ijen crater area, Banyupahit River and surrounding the sugar factory and also Belawan Fresh water source. Isotop analysis was done-by mass spectrometer. Based on analysis result have been gotten information that each location have vary of isotop value, Isotop concentration at Ijen crater was relative high so isotop concentration of Banyupahit river was also relative high although rather lower than lien Crater. Based on another interpretation, there are correlation at isotope concentration between Ijen crater and Banyupahit River

Electromigration of hydrogen and deuterium in vanadium, niobium, and tantalum

International Nuclear Information System (INIS)

Jensen, C.L.

1977-10-01

The electric mobility and effective valence of hydrogen and deuterium in vanadium, niobium, tantalum and three niobium-tantalum alloys were measured. A resistance technique was used to directly determine the electric mobility of hydrogen and deuterium at 30 0 C while a steady-state method was used to measure the effective valence. The use of mass spectrographic techniques on a single specimen which contained both hydrogen and deuterium greatly increased the precision with which the isotope effect in the effective valence could be measured

Use of isotope effects to elucidate enzyme mechanisms

International Nuclear Information System (INIS)

Cleland, W.W.

1982-01-01

The chemical bond breaking steps are normally not rate limiting for enzymatic reactions. However, comparison of deuterium and tritium isotope effects on the same reaction, especially when coupled with 13 C isotope effects for the same step measured with deuterated as well as unlabeled substrates, allows calculation of the intrinsic isotope effects on the bond breaking steps and thus a determination of the commitments to catalysis for the reactants. The variation in observed isotope effects as a function of reactant concentration can be used to determine kinetic mechanisms, while the pH variation of isotope effects can determine the stickiness of the reactants and which portions of the reactant mechanism are pH dependent. Finally the size of primary and secondary intrinsic isotope effects can be used to determine transition state structure

Research of catalysts for isotope enrichment of deuterium oxide in water - PX15-03/90 progress report

International Nuclear Information System (INIS)

1990-10-01

The operation results of pre-concentration stages from the Pilot Unity, and the technical information important to the project of development of catalyst for isotope concentration of deuterium oxides (D 2 O) are described. (C.G.C.)

High secondary [alpha]-deuterium kinetic isotope effect in the acetolysis and formolysis of dideuterioferrocenylmethyl benzoate

Energy Technology Data Exchange (ETDEWEB)

Asperger, S. (Research Center of the Croatian Academy of Sciences and Arts, Zagreb (Croatia)); Kukric, Z.; Sutic, D. (Sarajevo Univ. (Yugoslavia). Faculty of Natural Sciences and Mathematics); Saunders, W.H. Jr. (Rochester Univ., NY (United States). Dept. of Chemistry)

1992-02-01

Acetolysis and formolysis of dideuterioferrocenylmethyl benzoate exhibit large secondary deuterium kinetic isotope effects and an abnormal temperature dependence. In the presence of LiClO[sub 4], which prevents the reversion from solvent-separated to contact ion-pairs, K[sub H]/K[sub D] at 25 [sup o]C amount to 1.53 [+-] 0.02 (acetolysis) and 1.48 [+-] 0.03 (formolysis). In the presence of LiClO[sub 4] the ratios of Arrhenius pre-exponential factors, A[sub H]/A[sub D], are significantly less than unity and amount to 0.49 [+-] 0.01 (acetolysis) and 0.38 [+-] 0.04 (formolysis). In the absence of LiClO[sub 4] the A[sub H]/A[sub D] ratios are much smaller (0.02 both in acetolysis and formolysis). We suggest that these surprisingly low values result from a change in rate-determining step over the temperature range, from formation of the solvent-separated ion-pair at low temperatures to reaction of the dissociated carbocation with solvent at the highest temperatures. Whether tunnelling plays any role in these solvolyses is discussed. (Author).

Solvent isotope effects on the rates of alkylation of thiolamine models of papain

International Nuclear Information System (INIS)

Wandinger, A.; Creighton, D.J.

1980-01-01

As a test of whether it is chemically reasonable to attribute any or all of the observed kinetic solvent deuterium isotope effects reported on papain to the fundamental properties of the tautomerization equilibrium, the magnitudes of the solvent deuterium isotope effects on the rates of alkylation of the tautomeric forms of cysteine and β-mercaptoethylamine were determined for bromo- and chloroacetate, bromo- and chloroacetamide, as well as for methylbromoacetate. These thiolamines are viewed as elementary chemical models of the sulfhydryl group tautomerization equilibrium envisioned in the active site of papain. (Auth.)

Experimental studies on hydrogen isotopic deuterium from gas to liquid phase by catalytic exchange

International Nuclear Information System (INIS)

Luo Yangming; Wang Heyi; Liu Jun; Fu Zhonghua; Wang Changbin; Han Jun; Xia Xiulong; Tang Lei

2005-01-01

The experimental studies on hydrogen isotopic deuterium from gas to liquid phase were completed by mixed ratio 1:4 of Pt-SDB hydrophobic catalyst and hydrophilic packing. The influencing factors on number of transfer units (NTU) and transformation efficiencies of deuterium were researched. The results show that preferable NTU can be obtained by choosing suitable operational temperature and flux of exchange gas. The transformation rate increases with increasing liquid flux, but it cannot obviously be improved when liquid flux attains some level. The length of catalytic column has an obvious influence on transformation rate and 90% of transformation rate is obtained by 4 m column length at gas flux with 2 m 3 /h, liquid flux with 1-2 kg/h and 45 degree C. (author)

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

Science.gov (United States)

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...

Effect of Coulomb screening on deuterium-deuterium fusion cross-section

International Nuclear Information System (INIS)

Wang Shunjin

1991-01-01

The popular Gamow formula for the deuterium-deuterium fusion cross-section is generalized to take into account the Coulomb screening effect. The generalized formula has been used to discuss the fusion process occurring in the metal medium

Gamma-radiation and isotopic effect on the critical behavior in triglycine selenate crystals

Science.gov (United States)

Kassem, M. E.; Hamed, A. E.; Abulnasr, L.; Abboudy, S.

1994-11-01

Isotopic effects in pure and γ-irradiated triglycine selenate crystals were investigated using the specific heat ( Cp) technique. The obtained results showed an interesting dependence of the critical behavior of Cp on the deuterium content. With increasing content of deuterium, the character of the phase transition changed from a second order (γ-type) to a first order transition. After γ-irradiation, the behavior of Cp around the phase transition region was essentially affected. The transition temperature, Tc, decreased and Δ Cp depressed, and the transition became broad. It was noted that the effect of γ-irradiation is opposite to the isotopic effect.

Isotope mixtures of hydrogen in vanadium

International Nuclear Information System (INIS)

Mecking-Schloetensack, P.

1982-03-01

The properties of isotope-mixtures of Protium and Deuterium stored in Vanadium have been studied. Protium and Deuterium are existing as interstitial-atoms on tetrahedral sites as well as on octahedral sites in this system. This feature leads to large isotopic-effects between the two isotopes. The dependence of the thermodynamic functions like heat of solution, nonconfigurational entropy, specific heat and ordering temperatures from the composition of the isotope-mixture has been determined. (orig.)

Procedure and equipment for the separation of isotopes for deuterium upgrading and for the production of heavy water

International Nuclear Information System (INIS)

Schoell, M.

1981-01-01

The invention concerns a simple procedure for the separation of isotopes for the enrichment of deuterium and for the production of heavy water as well as the equipment necessary for carrying out the process. Methane is conducted over bacterial cultures oxidizing methane to water and carbon dioxide. An enrichment of deuterium takes place in non-oxidized methane. The bacterial cultures are placed on carriers that are arranged in oxidation columns as baffle plates. Several oxidation towers of this kind can be arranged in series. (orig./RW) [de

Pull-push mechanism for the 1,2-hydrogen rearrangement of carbenes. Substituent and deuterium isotope effects for thermal decomposition of 1-phenyl-2-diazopropanes

International Nuclear Information System (INIS)

Su, D.T.T.; Thornton, E.R.

1978-01-01

Intramolecular and intermolecular deuterium isotope effects have been measured for the thermal carbene H rearrangements of three substituted 1-phenyl-2-diazopropanes-1-d in hexane at 25 0 C. The isotope effects, k/sub H//k/sub D/, vary from ca. 1.2 to 1.5, increasing with electron-withdrawing substituents, for the formation of both cis- and trans-β-methylstyrenes. Product ratios were determined for these compounds as well as the corresponding undeuterated ones, permitting calculation of intermolecular primary and secondary isotope effects. In addition, the competition among the cis and trans products and the product of H migration from the terminal methyl group permitted determination of Hammett rho values of ca. -1 for the competition between benzylic and terminal migration. The results strongly indicate a ''pull-push'' mechanism, which can be pictured roughly as electrophilic attack on the C--H bond by the phantom p orbital of the carbene along with backside nucleophilic attack by the carbene unshared electron pair to push the H away and form the π bond. The data are believed to be consistent only with a nonzero barrier for the carbene hydrogen rearrangement

Kinetic isotope effects and aliphatic diazo-compounds

International Nuclear Information System (INIS)

Albery, W.J.; Conway, C.W.; Hall, J.A.

1976-01-01

Results are reported for the variation of the rate of decomposition of ethyl diazomalonate (EDM) and diazomalonate anions with pH and for the deuterium solvent isotope effect for EDM. The shape of the pH profile is explained by successive protonations of the anions. Ethyl diazoacetate is observed as an intermediate in the decomposition of EDM. The degree of proton transfer in the EDM transition state is deduced from the solvent isotope effect and the results together with those for other aliphatic diazo-compounds are discussed in terms of the Marcus theory. (author)

Gamma-radiation and isotopic effect on the critical behavior in triglycine selenate crystals

International Nuclear Information System (INIS)

Kassem, M.E.; Hamed, A.E.; Abulnasr, L.; Abboudy, S.

1994-01-01

Isotopic effects in pure and γ-irradiated triglycine selenate crystals were investigated using the specific heat (C p ) technique. The obtained results showed an interesting dependence of the critical behavior of C p on the deuterium content. With increasing content of deuterium, the character of the phase transition changed from a second order (λ-type) to a first order transition. After γ-irradiation, the behavior of C p around the phase transition region was essentially affected. The transition temperature, T c , decreased and ΔC p depressed, and the transition became broad. It was noted that the effect of γ-irradiation is opposite to the isotopic effect. (author)

Determination of Equine Cytochrome c Backbone Amide Hydrogen/Deuterium Exchange Rates by Mass Spectrometry Using a Wider Time Window and Isotope Envelope.

Science.gov (United States)

Hamuro, Yoshitomo

2017-03-01

A new strategy to analyze amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) data is proposed, utilizing a wider time window and isotope envelope analysis of each peptide. While most current scientific reports present HDX-MS data as a set of time-dependent deuteration levels of peptides, the ideal HDX-MS data presentation is a complete set of backbone amide hydrogen exchange rates. The ideal data set can provide single amide resolution, coverage of all exchange events, and the open/close ratio of each amide hydrogen in EX2 mechanism. Toward this goal, a typical HDX-MS protocol was modified in two aspects: measurement of a wider time window in HDX-MS experiments and deconvolution of isotope envelope of each peptide. Measurement of a wider time window enabled the observation of deuterium incorporation of most backbone amide hydrogens. Analysis of the isotope envelope instead of centroid value provides the deuterium distribution instead of the sum of deuteration levels in each peptide. A one-step, global-fitting algorithm optimized exchange rate and deuterium retention during the analysis of each amide hydrogen by fitting the deuterated isotope envelopes at all time points of all peptides in a region. Application of this strategy to cytochrome c yielded 97 out of 100 amide hydrogen exchange rates. A set of exchange rates determined by this approach is more appropriate for a patent or regulatory filing of a biopharmaceutical than a set of peptide deuteration levels obtained by a typical protocol. A wider time window of this method also eliminates false negatives in protein-ligand binding site identification. Graphical Abstract ᅟ.

Synthesis of deuterium-labeled prochlorperazine.

Science.gov (United States)

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

1983-06-01

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

Alternatives to isotope ratio mass spectrometry for the measurement of deuterium content of body water

International Nuclear Information System (INIS)

Bluck, L.J.C.

2000-01-01

The measurement of breast milk intake using the isotope dilution techniques is now well established. The methodology involves the administration of a bolus of tracer followed by observation of the kinetics of its passage though the system. For example in the popular 'dose to the mother' method a dose of labeled water is administered to the mother, and over the following days samples of body fluids are taken and the concentration of tracer determined in order to establish the rate of loss of tracer from her body. Likewise samples are taken from the breast fed infant in order to determine the rates of tracer intake and subsequent loss. Deuterium is the tracer of choice for these experiments since it is non-radioactive, and therefore suitable for use in these vulnerable subject groups, and also because of its relative cheapness. Conventionally isotope ratio mass spectrometry (IRMS) has been used for the determination of the amount of deuterium in the body fluids. However this methodology is expensive (an instrument might typically cost US$ 150,000), and it requires a considerable amount of dedicated technical expertise for its operation. Consequently such instrumentation is not widely available, and this has limited the number and scope of studies using this technique. Recently there have been reports of possible alternative technologies for the determination of deuterium in body water which appear attractive because of the wider general availability of the equipment required. It is the purpose of this report to assess these reported methods for their suitability for breast milk intake measurements

Calculation of carbon-14, chlorine-37, and deuterium kinetic isotope effects in the solvolysis of tert-butyl chloride

International Nuclear Information System (INIS)

Burton, G.W.; Sims, L.B.; Wilson, J.C.; Fry, A.

1977-01-01

In the solvolysis of tert-butyl chloride, satisfactory α-carbon-14, β-deuterium, and chlorine kinetic isotope effects (KIE) may be calculated for a productlike transition state characterized by bond orders n/sub C Cl/ = 0.2, n/sub C C/ = 1.18, and n/sub C H/ = 0.94, employing a diagonal valence force field, provided that allowance is made for hydrogen-bonded solvation of the developing chloride ion with n/sub Cl H/ approx. 0.05 (approx. 7 kcal/mole hydrogen bonds). The effect of the three solvating molecules appears to be to increase the ''effective'' mass of the incipient chloride ion and to decrease the loss of zero-point energy in going to the transition state. Reaction coordinates more complicated than a simple heterolysis of the carbon-chlorine bond appear to be unnecessary and there is no advantage in employing force fields more complex than a simple valence force field containing only diagonal elements for both the reactant and the transition state model. The structural and bonding features of the proposed transition state are in accord with earlier more qualitative conclusions concerning the polar nature and productlike character of the transition state, and provide a reasonable explanation of the kinetic and equilibrium isotope effects (EIE) for the reaction. An alternative transition state model involving weak solvent nucleophilic assistance provides reasonable calculated values for the KIE, but the EIE strongly suggest the importance of solvation of the leaving group which, together with the hyperconjugation of the β hydrogens, provides a preferred explanation of the tert-butyl solvolysis results

Process and device for step by step enrichment of deuterium and/or tritium by isotope exchange

International Nuclear Information System (INIS)

Iniotakis, N.; Decken, C.B. von der.

1984-01-01

Deuterium and/or tritium are bound to steam by isotope exchange after permeation through an exchange wall. Primary and secondary flows are guided by the counterflow principle. The secondary side has a metal oxide as oxidation catalyst. The plant can consist of several enrichment stages. The various flows and parts of the plant are described. (PW) [de

Deuterium isotope effect on metabolism of N-nitrosodimethylamine in vivo in rat

International Nuclear Information System (INIS)

Swann, P.F.; Mace, R.; Angeles, R.M.; Keefer, L.K.

1983-01-01

The maximal rates of metabolic oxidation of N-nitrosodimethylamine (NDMA) and N-nitrosodimethylamine-d6 (NDMA-d6) in vivo (VH and VD, respectively) have been measured by following 14CO2 exhalation in rats after intraperitoneal injection of the two 14C-labelled carcinogens at high doses (20 or 40 mg/kg). Complete deuteration of NDMA reduced only slightly the maximal rate of metabolism when the two substrates were administered separately (VH/VD approximately 1.2). However, much larger (approximately 4-fold) deuterium isotope effects were observed when mixtures of NDMA with NDMA-d6 were injected. These results are tentatively interpreted as evidence that C-H bond cleavage is not a rate limiting feature of overall metabolism, but that the complex between NDMA and the principal enzyme(s) metabolizing it in vivo freely equilibrates with unbound substrate. Single, large, intraperitoneal doses of NDMA and NDMA-d6 produced a similar alkylation of rat liver DNA and also of kidney DNA. However, a small oral dose (54 micrograms/kg) of NDMA-d6 produced 1/3 less alkylation of liver DNA and 3 times as much alkylation of kidney DNA as did an equimolar dose of NDMA. The reduction in alkylation of liver DNA correlates well with, and possibly explains, the decreased ability of NDMA-d6 to induce liver tumors in rats. The associated increase in the alkylation of kidney DNA suggests that this change is due to a decrease in the amount of nitrosamine removed from the portal blood on the first pass through the liver

Gamma-radiation and isotopic effect on the critical behavior in triglycine selenate crystals

Energy Technology Data Exchange (ETDEWEB)

Kassem, M.E.; Hamed, A.E.; Abulnasr, L.; Abboudy, S. [Alexandria Univ. (Egypt). Dept. of Physics

1994-11-01

Isotopic effects in pure and {gamma}-irradiated triglycine selenate crystals were investigated using the specific heat (C{sub p}) technique. The obtained results showed an interesting dependence of the critical behavior of C{sub p} on the deuterium content. With increasing content of deuterium, the character of the phase transition changed from a second order ({lambda}-type) to a first order transition. After {gamma}-irradiation, the behavior of C{sub p} around the phase transition region was essentially affected. The transition temperature, T{sub c}, decreased and {Delta}C{sub p} depressed, and the transition became broad. It was noted that the effect of {gamma}-irradiation is opposite to the isotopic effect. (author).

Process for the production of hydrogen/deuterium-containing gas

International Nuclear Information System (INIS)

Nitschke, E.; Desai, A.; Ilgner, H.

1978-01-01

A process for the production of hydrogen/deuterium-containing gas is described in which the enriched condensate obtained from the production of a hydrogen/deuterium-containing gas mixture is collected and subjected to a direct exchange of isotopes with the feedsteam admitted to the process. Such condensate can be brought into direct exchange of isotopes with the gas water vapor mixture within the process, viz. ahead of the CO conversion section. The exchange of isotopes may be performed according to the counter-current principle. If it is intended to maintain in the hydrogen/deuterium-containing gas a certain definite content of water vapor whose phase condition is superior to the condition achieved when using normal cooling water, this gas, at least 0.6 kg/m 3 of gas, is subjected to an exchange of isotopes with the water fed additionally into the process

Deuterium isotopic effects connected with unimolecular and concerted mechanisms. The case of 1-deutero-2-chloro alcohols; Effets isotopiques du deuterium attaches a des mecanismes unimoleculaires et concertes. Cas des deutero-1-chloro-2 alcools

Energy Technology Data Exchange (ETDEWEB)

Jambon, C

1962-07-01

After a bibliographic analysis of the probable causes of isotopic effects and their comparison, with the simplifications provided by the athermal model, a discussion of the isotopic effect of deuterium in organic molecules in terms of structural influences is presented, showing the important role of the C-D bond length which is shorter than the C-H bond length, and of the D atom's Van der Waals radius, shorter than that of the H atom. Kinetic measurements were carried out on some reactions involving the mechanisms proposed: unimolecular ionizations and halogen concentrates. The structural models chosen are: 2-chloro-cyclo-hexanols cis and trans 1-H and 2-D; 2-chloro-cyclo-pentanols cis trans 1-H and 1-D; 1-phenyl-l-chloro-2-propanol threo 2-H and 2-D. (author) [French] Apres une analyse bibliographique des causes probables d'effets isotopiques et leur comparaison, avec les simplifications qu'apporte le modele athermique, on a entrepris l'etude de la discussion isotopique du deuterium dans des molecules organiques en termes d'influences structurelles, cherchant a degager le role important de la longueur de la liaison C-D plus courte que C-H, et du rayon de Van der Waals de l'atome de D plus petit que celui de H. On a effectue des mesures cinetiques sur quelques reactions invoquant les mecanismes envisages: ionisations unimoleculaires et concentrees d'halogenes. Les modeles structuraux choisis sont: chloro 2 - cyclohexanols cis et trans H 1 et D 1; chloro 2 - cyclopentanols cis et trans H 1 et D 1; phenyl 1 - chloro 1 - propanol 2 threo H 2 et D 2. (auteur)

Deuterium isotopic effects connected with unimolecular and concerted mechanisms. The case of 1-deutero-2-chloro alcohols; Effets isotopiques du deuterium attaches a des mecanismes unimoleculaires et concertes. Cas des deutero-1-chloro-2 alcools

Energy Technology Data Exchange (ETDEWEB)

Jambon, C

1962-07-01

After a bibliographic analysis of the probable causes of isotopic effects and their comparison, with the simplifications provided by the athermal model, a discussion of the isotopic effect of deuterium in organic molecules in terms of structural influences is presented, showing the important role of the C-D bond length which is shorter than the C-H bond length, and of the D atom's Van der Waals radius, shorter than that of the H atom. Kinetic measurements were carried out on some reactions involving the mechanisms proposed: unimolecular ionizations and halogen concentrates. The structural models chosen are: 2-chloro-cyclo-hexanols cis and trans 1-H and 2-D; 2-chloro-cyclo-pentanols cis trans 1-H and 1-D; 1-phenyl-l-chloro-2-propanol threo 2-H and 2-D. (author) [French] Apres une analyse bibliographique des causes probables d'effets isotopiques et leur comparaison, avec les simplifications qu'apporte le modele athermique, on a entrepris l'etude de la discussion isotopique du deuterium dans des molecules organiques en termes d'influences structurelles, cherchant a degager le role important de la longueur de la liaison C-D plus courte que C-H, et du rayon de Van der Waals de l'atome de D plus petit que celui de H. On a effectue des mesures cinetiques sur quelques reactions invoquant les mecanismes envisages: ionisations unimoleculaires et concentrees d'halogenes. Les modeles structuraux choisis sont: chloro 2 - cyclohexanols cis et trans H 1 et D 1; chloro 2 - cyclopentanols cis et trans H 1 et D 1; phenyl 1 - chloro 1 - propanol 2 threo H 2 et D 2. (auteur)

On the Effect of Planetary Stable Isotope Compositions on Growth and Survival of Terrestrial Organisms.

Directory of Open Access Journals (Sweden)

Xueshu Xie

Full Text Available Isotopic compositions of reactants affect the rates of chemical and biochemical reactions. Usually it is assumed that heavy stable isotope enrichment leads to progressively slower reactions. Yet the effect of stable isotopes may be nonlinear, as exemplified by the "isotopic resonance" phenomenon. Since the isotopic compositions of other planets of Solar system, including Mars and Venus, are markedly different from terrestrial (e.g., deuterium content is ≈5 and ≈100 times higher, respectively, it is far from certain that terrestrial life will thrive in these isotopic conditions. Here we found that Martian deuterium content negatively affected survival of shrimp in semi-closed biosphere on a year-long time scale. Moreover, the bacterium Escherichia coli grows slower at Martian isotopic compositions and even slower at Venus's compositions. Thus, the biological impact of varying stable isotope compositions needs to be taken into account when planning interplanetary missions.

Kinetic isotope effect in the thermolysis of methylenecyclobutane

International Nuclear Information System (INIS)

Chickos, J.S.

1979-01-01

The intramolecular kinetic isotope effect for the thermolysis of equilibrated methylenecyclobutane-d 2 was investigated at 515 0 C as a function of pressure. A high-pressure value of k/sub H/k/sub D/ (ethylene/ethylene-d 2 ) = 0.9 was obtained at 13 cm of N 2 pressure. This value decreased to 0.86 at 70 μm total pressure. No intermolecular kinetic isotope effect was measured for the formation of ethylene from labeled and unlabeled methylenecyclobutane. The pressure and temperature dependence of the intramolecular kinetic isotope effect was used as evidence in establishing the inverse nature of the effect. The isotope effect observed was explained in terms of competing equilibrium and kinetic isotope effects in which the equilibrium isotope effects dominate. It was concluded on the bases of these results that an acyclic intermediate is involved in the fragmentation of methylenecyclobutane to ethylene and allene. The results also support the notion that deuterium prefers to accumulate at the methylene group with the greatest p character in the carbon--hydrogen bond. 1 figure, 4 tables

Effects of deuterium depleted water on reproduction of Rainbow fish

International Nuclear Information System (INIS)

Stefanescu, Ion; Saros-Rogobete, Irina; Titescu, Gheorghe; Caraus, Ion; Pricop, Ferdinand

2001-01-01

The paper refers to an isotopic composition used to prepare fecundating solutions for artificial reproduction of fish. The solution is constituted as a mixture of deuterium depleted water and natural water (whose isotopic concentration is of 85-90 ppm D/(D+H)) in which we can add activating and energizing substances. This fecundating solution ensures an improved fecundating level of fish roe, increase life index in the next growth up stages and increase fish resistance at special medium conditions. (authors)

Deuterium-depleted water. Short history and news

International Nuclear Information System (INIS)

Stefanescu, Ioan; Tamaian, Radu; Titescu, Gheorghe

2002-01-01

Deuterium-depleted water represents water that has an isotopic content lower than 144 ppm D/(D+H) which is the natural isotopic content of water. DDW is a non-toxic product. Knowing that deuterium content of water has a significant influence on living organisms, since 1996 NIR-DCIT ICSTI at Rm. Valcea cooperated with Romanian specialized instititutes for biological effects' evaluation of DDW. The investigations lead to the conclusion that DDW caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects. Animals teated with DDW showed an increase of the resistance both to sub lethal and to lethal gamma radiation doses. DDW stimulates immune defense reactions. Investigations regarding artificial reproduction of fish with DDW fecundated solutions confirmed favorable influence in embryo growth stage and resistance in next growth stages. One can remark the favourable influence of DDW on biological process in plants in various ontogenetic stages. (authors)

The H{sup +}{sub 3} + H{sub 2} isotopic system. Origin of deuterium astrochemistry

Energy Technology Data Exchange (ETDEWEB)

Hugo, Edouard Jean-Marie

2008-07-01

Dense cold molecular clouds reckoned to be stellar nurseries are the scene of an extreme molecular deuteration. Despite the cosmic D/H ratio of {proportional_to}10{sup -5}, molecular species in prestellar cores are observed to contain nearly as much deuterium as hydrogen. This astonishing deuterium enrichment promoted by low temperatures is the work of H{sup +}{sub 3}. It is the key species which unlocks the deuterium from its HD reservoir via reactions like H{sup +}{sub 3}+HD {r_reversible} H{sub 2}D{sup +}+H{sub 2} and drags it further to other species in successive reactions. For this reason, the H{sup +}{sub 3}+H{sub 2} isotopic system is outstandingly critical for the astrochemistry of cold environments. However, its understanding is yet incomplete and insufficient. This thesis thus focuses on the H{sup +}{sub 3}+H{sub 2} isotopic system from a theoretical, experimental and astronomical point of view giving a particular look into the role of nuclear spins. As a first step, the stringent nuclear spin selection rules in associative, dissociative and reactive collisions are investigated. This purely theoretical study zooms into the details of the nuclear spin wavefunctions and shows that their permutation symmetry representation is necessary and sufficient, contrary to their angular momentum representation. Additionally, a new deterministic interpretation of nuclear spins in chemical reactions is proposed. Based on these considerations, a complete set of state-to-state rate coefficients for all H{sup +}{sub 3} + H{sub 2} isotopic variants is calculated using a microcanonical model leaned on phase space theory. An experimental study is conducted in parallel with a 22-pole ion trap apparatus in order to inspect the influences of temperature and H{sub 2} ortho-to-para ratio. The good overall agreement between experimental and theoretical results supports the validity and utility of the calculated set of rate coefficients. Furthermore, the potentiality of the 22-pole

NMR spectroscopic determination of an equilibrium isotope effect on the hydration of cobalt(II)

International Nuclear Information System (INIS)

Evilia, R.F.; Saunders, M.

1985-01-01

A recently reported NMR method for the measurement of deuterium equilibrium isotope effects is applied to the hydration of the paramagnetic cobalt(II) ion. An isotope effect of about 1.3% is measured. A substantial difference between the intrinsic shift of H 2 O and D 2 O when coordinated to cobalt is also measured

The hydrogen and deuterium concentrations in chondrites

International Nuclear Information System (INIS)

Robert, F.; Merlivat, L.

1978-01-01

Water and isotopic concentration of H 2 O + are reported. It shows a correlation between the water, the deuterium concentrations and the petrologic types of chondrites. The Chainpur meteorite has been divided into several mineralogical fractions and the results are reported. The results of Orgueil are also reported. The correlation shows that as the sulfate content increases, the water and deuterium contents decrease. The terrestrial contamination is discussed and possible deuterium variation models are presented

What is the effect of variations optimization of the transition state on α-deuterium secondary kinetic isotope effects? A prototype: CD3H + H right-reversible CD3 + H2

International Nuclear Information System (INIS)

Lu, Dahong; Maurice, D.; Truhlar, D.G.

1990-01-01

Variational Transition state theory calculations with semiclassical transmission coefficients have been carried out for a prototype case of α-deuterium secondary kinetic isotope effects (KIEs) in a reaction involving the transformation of an sp 3 carbon to sp 2 , in particular for the reactions of CH 4 and CD 3 H with H and D. The authors also study the KIE for the reverse direction and for the reactions of CH 4 and CD 3 H with D. They find that the variational transition states lead to significantly different nontunneling KIEs than the conventional ones, e.g., 1.22 vs. 1.07, and the inclusion of multidimensional tunneling effects increases the discrepancy even more. The origins of these variations and tunneling effects are examined in detail in terms of structures, vibrational frequencies, and the curvature of the reaction path. The conclusions have wide implications for the validity of conventional treatments of kinetic isotope effects. They predict some particularly large secondary KIEs at low temperature, and these predictions can be tested by future experiments

Isotopic effects in the muon transfer from pmu and dmu to heavier atoms.

Science.gov (United States)

Dupays, Arnaud

2004-07-23

The results of accurate hyperspherical calculations of the muon-transfer rates from muonic protium and deuterium atoms to nitrogen, oxygen, and neon are reported. Very good agreement with measured rates is obtained and, for the three systems, the isotopic effect is perfectly reproduced. The transfer rate is higher for deuterium in the cases of nitrogen and neon due to constructive interferences between two transfer paths. The lower transfer rate for deuterium in the case of oxygen results from a large resonant contribution. Copyright 2004 The American Physical Society

Recent experimental results on solutions of deuterium in lithium

International Nuclear Information System (INIS)

Ihle, H.R.; Wu, C.H.

1976-01-01

The existence of a number of stable molecules containing lithium and hydrogen isotopes in the saturated vapor over dilute solutions of hydrogen isotopes in lithium causes an unexpectedly high density of hydrogen isotopes in the vapor at high temperature. An evaluation of the partial pressures of the gas species Li, Li 2 , LiD, Li 2 D, LiD 2 and D 2 over solutions of deuterium in lithium measured in the temperature range 770 to 970 0 K, and extrapolation to higher temperatures, leads to the conclusion that the ratio of the atom fraction of deuterium in the gas to its atom fraction in the liquid exceeds unity above approximately 1240 0 K; this ratio is independent of the deuterium atom fraction in the liquid at low concentrations. Therefore the thermodynamic supposition that hydrogen isotopes can be separated from lithium by fractional distillation even at extremely low concentration exists. A direct verification of this phenomenon was made by Rayleigh distillation of Li-D solutions in the temperature range 970 to 1600 0 K. These measurements yield also the ratio of the deuterium atom fraction in the gas to that in the liquid and are in good agreement with the data obtained by extrapolation of partial pressures. The enrichment and depletion of deuterium in dependence on the number of theoretical plates of a distillation column at total reflux is calculated using the results

Chemical and isotopic composition of precipitations in Syria

International Nuclear Information System (INIS)

Abou Zakhem, B.; Hafez, R.

2008-01-01

13 meteoric stations were selected in syria for cumulative monthly rainfall sampling during two hydrological cycles; 1991-1992 and 1992-1993. The chemical and isotopic compositions of monthly precipitation were studied. The winter and spring rainfall isotopic characteristics were determined, in addition to the syrian or local meteoric line (SMWL) was estimated with a slope of 6.63 and that of both syria and Jordan of 6.73. The effect of climatic factors as temperature and relative air humidity on oxygen-18, deuterium and d-excess were studied and it was found that the relationship between temperature and oxygen-18 and deuterium is a positive linear correlation; however, it is a negative correlation with d-excess. The mean seasonal variation amplitude was determined by 6%, and the amount effect on isotopic content of precipitation was studied. The geographic factors and its affect on isotopic contents of precipitation such as altitude were considered, furthermore, the isotopic gradient with altitude was determined for both oxygen-18 and deuterium (-0.14% and - 0.84%/100 m elevation respectively). The spatial variability of oxygen-18, deuterium, tritium and d-excess indicted the effect of mountain chains and gaps between mountains on the isotopic content of precipitation, the continental effect on tritium build-up by about 33% per 100 Km from the coast. The increase of d-excess values towards the south west proves the eastern mediterranean climate type over this region. (author)

Thermodynamic isotope effects of D2 and T2 reaction with uranium

International Nuclear Information System (INIS)

Huang Gang; Long Xinggui; Liang Jianhua; Yang Benfu; Liu Wenke

2010-01-01

The p-c-T curves of deuterium and tritium absorption by uranium and p-t curves of desorption were measured. The balance pressure of absorption and desorption on different temperatures were got and then the thermodynamic parameters were determined according to the Van't Hoff equation. It shows that the balance pressure of deuterium absorption is lower than that of tritium absorption on the same temperature and atom ratio. It has the same phenomena for desorption but there are obvious hysteresis effect for reversible process of absorption and desorption. There are a little thermodynamic isotope effects when deuterium and tritium absorption and desorption by uranium estimating from enthalpy and entropy values. (authors)

Metabolism of N-methylformamide in mice: primary kinetic deuterium isotope effect and identification of S-(N-methylcarbamoyl)glutathione as a metabolite

International Nuclear Information System (INIS)

Threadgill, M.D.; Axworthy, D.B.; Baillie, T.A.; Farmer, P.B.; Farrow, K.C.; Gescher, A.; Kestell, P.; Pearson, P.G.; Shaw, A.J.

1987-01-01

S-(N-Methylcarbamoyl)glutathione has been identified by cesium ion liquid secondary ion mass spectrometry as a biliary metabolite in mice of the experimental antitumor agent and hepatotoxin N-methylformamide. Metabolism of N-methylformamide to urinary methylamine, urinary N-acetyl-S-(N-methylcarbamoyl)-cysteine and biliary S-(N-methylcarbamoyl)glutathione was found to be subject to large intermolecular primary kinetic isotope effects when hydrogen was replaced by deuterium in the formyl group (kH/kD = 5.5 +/- 0.2, 4.5 +/- 1.0 and 7 +/- 2, respectively), as shown by mass spectrometry of derivatives of these metabolites. These values indicate the existence of a common metabolic precursor for each of these metabolites. In particular, methylamine is shown not to arise from simple enzymatic hydrolysis of N-methylformamide but is associated with an oxidative process. Therefore, it is highly likely that N-methylformamide is oxidized and conjugated to form S-(N-methylcarbamoyl)glutathione which is metabolized further to N-acetyl-S-(N-methylcarbamoyl) cysteine. Either of these thiocarbamates could be hydrolyzed to give the parent thiol and the observed metabolic end products, methylamine and carbon dioxide. The presence of deuterium in the formyl moiety of N-methylformamide reduced markedly the hepatotoxicity of the compound, as shown by measurements of the activities of appropriate hepatic enzymes in plasma

Chemical and isotopic composition of precipitations in Syria

International Nuclear Information System (INIS)

Abou Zakhem, B.; Hafez, R.

2007-05-01

The objective of this study is to determine isotopic characteristics of precipitation, the climatic and geographical conditions affecting isotopic composition in order to obtain the input function of groundwater to evaluate the water resources.13 meteoric stations were selected in Syria for cumulative monthly rainfall sampling during two hydrological cycles; 1991-1992 and 1992-1993. The chemical and isotopic compositions of monthly precipitation were studied. The winter and spring rainfall isotopic characteristics were determined, in addition to the Syrian meteoric line (SMWL) was estimated with a slope of 6.62 and that of both Syria and Jordan of 6.73. The effect of climatic factors as temperature and relative air humidity on oxygen-18, deuterium and d-excess were studied and it was found that the relationship between temperature and oxygen-18 and deuterium is a positive linear correlation; however, it is a negative correlation with d-excess. The mean seasonal variation amplitude of 18 O was about 6%, and the amount effect on isotopic content of precipitation was studied. The geographic factors and its affect on isotopic contents of precipitation such as altitude were considered, furthermore, the isotopic gradient with altitude was determined for both oxygen-18 and deuterium (-0.14 % and -0.84% /100m respectively). The spatial distribution of oxygen-18, deuterium, tritium and d-excess indicted the effect of mountain chains and gaps between mountains on the isotopic content, the continental effect on tritium build-up by about 33% per 100 Km from the coast. The increase of d-excess values towards the south west proves the eastern Mediterranean climate type over this region.(author)

Some methods for labelling organic compounds by deuterium

International Nuclear Information System (INIS)

Moustapha, C.

1988-01-01

The rapid growth of knowledge in the fields of biochemistry, physiology, and molecular biology reflects to a considerable degree the utilization of stable isotopes (specially deuterium) in the study of chemical reactions and fragmentation mechanisms in mass spectrometry, as well as in the pharmacological and biological studies. Organic compounds maybe labelled by deuterium through classic organic reactions by using special deuterated solvents and reagents. This article discusses some reactions, with examples on how to prepare labelled compounds with high isotopic purety. These reactions are: exchange reactions in acid and alkaline media (the exchange in the chromatographic column in liquid and gas phases, the exchange in homogenous medium), reduction reactions of functional groups as well as saturation of the double bounds by deuterium using hydrogenation catalystes, electrochemical reactions using KOLBE, and photochemical reactions. This article also deals with spectroscopic properties of deuterium and the methods which are used to identify its compounds such as infrared, nuclear magnetic resonance, and mass spectroscopy. 37 refs., 2 figs

Solvent effects and secondary isotope effects for probing diradical character in the thermal decarboxylation of β-peroxylactones

International Nuclear Information System (INIS)

Adam, W.; Cueto, O.; Guedes, L.N.; Rodriguez, L.O.

1978-01-01

The lack of solvent effects in the activation parameters and product distribution and the lack of secondary deuterium isotope effects at the α-carbon and β-alkyl migrant substantiates that the thermal decarboxylation of β-peroxy lactones proceeds via a 1,5-diradical

Ionic conductivity in aqueous solutions: deuterium isotope effect

International Nuclear Information System (INIS)

Samanta, Alok; Ghosh, Swapan K.

1997-01-01

A simple theoretical investigation of the calculation of ionic conductivity in aqueous solution is presented. The dipolar hard sphere model for the solvent which has been successful elsewhere has been employed here and it has been possible to reproduce the experimental results quite accurately for both water and heavy water using only two parameters. In a more detailed theoretical approach one should employ better models for water with proper account of its vibrations, liberations and also hydrogen bonding. It is also of interest to study the temperature effect and the concentration dependence of the conductivity. The time-dependent friction can also be calculated from the present formalism and be used for the study of isotope effect in proton transfer reactions or other aspects of chemical dynamics

Meaning of the Deuterium excess in the interpretation of δ 18O and δ 2H stable isotopes in hydrogeological studies

International Nuclear Information System (INIS)

Valencia, Jacinto

2013-01-01

An analysis element that helps with information on the interpretation of stable isotopes δ 18 O and deuterium in hydrogeological studies is called deuterium excess δ. In the present study, it has been used to interpret the weather, evaporation, humidity and wind conditions at the time of the precipitation in the Altiplano region of Puno, which have led to leaks of mine under study. The values obtained from the calculation of the deuterium excess δ of the seepage water samples are in the order of +15o/oo, indicating that the characteristics of the rainfall in the region have dominated high land desert climate conditions, different the current, ie, low humidity at the time of precipitation and further filtering these waters have received contribution of close water basin, evaporated and could come from Lake Titicaca. (author).

Method for enriching and separating heavy hydrogen isotopes from substance streams containing such isotopes by means of isotope exchange

International Nuclear Information System (INIS)

Knochel, A.; Eggers, I.; Klatte, B.; Wilken, R. D.

1985-01-01

A process for enriching and separating heavy hydrogen isotopes having a heavy hydrogen cation (deuterium and/or tritium) from substance streams containing them, wherein the respectively present hydrogen isotopes are exchanged in chemical equilibria. A protic, acid solution containing deuterium and/or tritium is brought into contact with a value material from the group of open-chained polyethers or aminopolyethers, macro-monocyclic or macro-polycyclic polyethers, macro-monocyclic or macro-polycyclic amino polyethers, and mixtures of these values, in their free or proton salt form to form a reaction product of the heavy hydrogen cation with the value or value salt and bring about enrichment of deuterium and/or tritium in the reaction product. The reaction product containing the value or value salt is separated from the solution. The separated reaction product is treated to release the hydrogen isotope(s) to be enriched in the form of deuterium oxide (HDO) and/or tritium oxide (HTO) by regenerating the value or its salt, respectively. The regenerated value is returned for reuse

Influence of deuterium-depleted water on living organisms

International Nuclear Information System (INIS)

Stefanescu, I.; Titescu, Gh.; Croitoru, Cornelia; Saros-Rogobete, Irina

2000-01-01

Deuterium-depleted water (DDW) production technique consists in the separation of deuterium from water by means of an continuos distillation process under a pressure value of about 133,3 mbar. Water that is used as basic material has an isotopic content of 144 ppm D/(D+H). DDW results as distillate with an isotopic deuterium content of 15-80 ppm, depending on the level we want to achieve. Beginning with 1996 NIR and DCIT Rm. Valcea, which is a DDW producer, co-operated with Romanian specialised institutes for biological effects' evaluation of DDW. These investigations led to the next conclusions: - DDW caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tonus and vascular reactivity produced by the DDW persist after the removal of the vascular endothelium; - Animals treated with DDW showed an increase of the resistance both to sublethal and to lethal gamma radiation doses, suggesting a radioprotective action by the stimulation of non-specific immune defence mechanisms; - DDW stimulate immune defence reactions, represented by the opsonic, bactericidal and phagocyte capacity of the immune system, together with increase in the numbers of polymorphonuclear neutrophils; - Investigations regarding artificial reproduction of fish with DDW fecundated solutions confirmed favourable influence in embryo growth stage and resistance in next growth stages; - It was studied germination, growth and quantitative characters' variability at plants; one can remark the favourable influence of DDW on biological process at plants in various ontogenic stages. Further investigations are needed in order to establish the influence of deuterium-depleted water on living organisms. (authors)

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

Science.gov (United States)

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.

Hydrogen/deuterium exchange in mass spectrometry.

Science.gov (United States)

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.

D/H isotope effects in π-complexes of deuterated hexamethylbenzenes with the nitrosonium cation

International Nuclear Information System (INIS)

Borodkin, G.I.; Elanov, I.R.; Shakirov, M.M.; Shubin, V.G.

1993-01-01

The isotope effects of deuterium, manifested in the 13 C NMR spectra of complexes of deuterated hexamethylbenzenes C 6 (CD 3 ) n ·(CH 3 ) 6-n with the nitrosonium cation, have been studied. The small values observed for the isotopic perturbation are evidence of π-bonding of the NO + group to the hexamethylbenzene molecule. The applicability of an additive scheme of calculation of isotope effects for the ring carbon atoms of the complexes, based on the increment of replacement of the CH 3 group by CD 3 in hexamethylbenzene, has been demonstrated

DeUterium industrial production - tome 8

International Nuclear Information System (INIS)

Chagas, T.P.

1987-01-01

Some selected bibliographical references about processes for deuterium industrial production are presented, as follow: isotope exchange H 2 S-H 2 O and NH 3 -H 2 , eletrolysis and distillation. (E.G.) [pt

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

Energy Technology Data Exchange (ETDEWEB)

Taylor, C.N., E-mail: chase.taylor@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Shimada, M.; Merrill, B.J. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Akers, D.W. [Experimental Programs, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Hatano, Y. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan)

2015-08-15

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.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Nucleophilic addition to olefins. 7. Kinetic deuterium isotope effects as criterion for an enforced preassociation mechanism in the hydrolysis of substituted benzylidene Meldrum's acids

International Nuclear Information System (INIS)

Bernasconi, C.F.; Leonarduzzi, G.D.

1982-01-01

The hydrolysis of the title compounds occurs in four steps: (1) nucleophilic attack by water or hydroxide ion to form the addition complex T/sub OH/ - ; (2) carbon protonation of T/sub OH/ - to form T/sub OH/ 0 ; (3) oxygen deprotonation of T/sub OH/ 0 to form T/sub OH/ 0 - ; (4) collapse of the tetrahedral intermediate T/sub OH/ - into the respective benzaldehyde and Meldrum's acid anion. There is also a water-catalyzed collapse of T/sub OH/ 0 which becomes dominant in strongly acidic solution. In basic solution carbon protonation of T/sub OH/ - (step 2) is rate limiting; in strongly acidic media the water-catalyzed collapse of T/sub OH/ 0 is rate limiting for all substrates. In moderatly acidic solution two types of behavior were observed. With the p-nitro derivative step 4 is rate limiting at high, step 3 at low buffer concentrations. The latter situation is equivalent to a diffusion-controlled trapping mechanism in the reverse direction. With the parent and the p-methoxy derivative, collapse of T/sub OH/ 0 - occurs before the protonated base catalyst generated in step 3 can diffuse away; this is equivalent to an enforced preassociation mechanism in the reverse direction and is analogous to the reaction of thiol anions with acetaldehyde studied by Gilbert and Jencks. Our interpretation is strongly supported by (1) α secondary kinetic deuterium isotope effects which are large for the preassociation mechanism but essentially nil for the trapping mechanism and (2) by Bronsted #betta# values around 0.8 in the case of the preassociation mechanism and 1.0 for the trapping mechanism. The mechanism for the water-catalyzed collapse of T/sub OH/ 0 - is probably concerted, a conclusion which is supported by a large positive deviation from the Bronsted plot for base catalysis and by a large α secondary kinetic deuterium isotope effect

Method to separate deuterium isotopes using ethylene and ethylene dichloride

International Nuclear Information System (INIS)

Benson, S.W.

1979-01-01

The separation of deuterium by the dissociation of ethylene vinyl chloride, 1,2-dichloro-ethanes or propylene with the help of intensive, matched infrared lasers enables a relatively good yield if operated on a large scale, e.g. in refineries with large through-put. The deuterium from the laser photolysis of ethylene and vinyl chloride is found in the acetylene formed, which has to be separated off and processed. When using dichloroehtane, the deuterium is found in the vinal chloride formed. The methods are briefly described. (UWI) [de

Deuterium isotope differences in 2-propanone (CH3)2CO/(CD3)2CO: a high-pressure sound-speed, density, and heat capacities study

International Nuclear Information System (INIS)

Szydlowski, J.; Gomes de Azevedo, R.; Rebelo, L.P.N.; Esperanca, J.M.S.S.; Guedes, H.J.R.

2005-01-01

A new high-pressure, non-intrusive ultrasonic microcell [J. Chem. Thermodyn. 36 (2004) 211-222] was used to carry out sound-speed measurements in deuteriated 2-propanone (acetone-d 6 ) in broad ranges of temperature (288 6 . (p, ρ, T) data for acetone-d 6 were also determined but in a narrower T, p range (298 to 333 K; 0.1 to 60 MPa). In this interval, several thermodynamic properties were thus determined, such as: isentropic (κ s ) and isothermal (κ T ) compressibility, isobaric thermal expansivity (α p ), isobaric (c p ) and isochoric (c v ) specific heat capacity, and the thermal pressure coefficient (γ v ). Comparisons with our data for acetone-h 6 enabled us to establish the magnitude and sign of deuterium isotope effects for identical properties. These effects are a consequence of distinct vibrational mode frequencies in an isotope-invariant force constants' field. Molar heat capacities and their isotope effects were theoretically determined by employing an Einstein-like model for the vibrational frequencies of acetone-h 6 and acetone-d 6

Clumped isotope effects during OH and Cl oxidation of methane

DEFF Research Database (Denmark)

Whitehill, Andrew R.; Joelsson, Lars Magnus T.; Schmidt, Johan Albrecht

2017-01-01

A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH was produ......A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH...... effects for singly substituted species were consistent with previous experimental studies. For doubly substituted methane, 13CH3D, the observed kinetic isotope effects closely follow the product of the kinetic isotope effects for the 13C and deuterium substituted species (i.e., 13,2KIE = 13KIE × 2KIE...... reactions. In a closed system, however, this effect is overtaken by the large D/H isotope effect, which causes the residual methane to become anti-clumped relative to the initial methane. Based on these results, we demonstrate that oxidation of methane by OH, the predominant oxidant for tropospheric methane...

Electromigration of hydrogen and deuterium in vanadium and niobium by a resistance method

International Nuclear Information System (INIS)

Peterson, D.T.; Jensen, C.L.

1978-01-01

The electric mobility of hydrogen and deuterium has been measured at 30 0 C in niobium (Cb) and vanadium by a resistance method. The electric mobility was found to be 5.7 x 10 -4 cm 2 /V-s for hydrogen and 2.8 x 10 -4 for deuterium in niobium. In vanadium the electric mobilities were 2.3 x 10 -3 and 1.3 x 10 -3 cm 2 /V-s for hydrogen and deuterium, respectively. The effective charges calculated using reported diffusion coefficients are positive and are slightly greater for deuterium than for hydrogen in both vanadium and niobium. The resistivity increase due to the hydrogen isotopes in vanadium and niobium was also measured. Hydrogen was found to contribute 0.65 μ ohm-cm/at. % and deuterium 0.58 μ ohm-cm/at. % to the resistivity of niobium. In vanadium, the solute resistivities were found to be 0.98 μ ohm-cm/at. % and 0.90 μ ohm-cm/at. % for hydrogen and deuterium, respectively

Synthesis of deuterium-labelled viloxazine. [Antidepressant

Energy Technology Data Exchange (ETDEWEB)

Mamada, Kumiko; Furuta, Takashi; Kasuya, Yasuji

1988-06-01

The synthesis of deuterium-labelled viloxazine with high isotopic purity is described. The synthetic procedures employ alkylation of 2-(benzyloxy)phenol with (/sup 2/H/sub 5/)ethyl iodide for the introduction of deuterium. Catalytic removal of the benzyl group of the deuterated product followed by reaction with epichlorohydrin afforded 1,2-epoxy-3-(2'-pentadeuteroethoxy-phenoxy)propane. Addition of 2-aminoethyl hydrogen sulphate to the epoxide and subsequent ring formation into a morpholine derivative produced the desired (/sup 2/H/sub 5/)viloxazine.

Deuterium kinetic isotope effects in the 1,4-dimethylenecyclohexane boat cope rearrangement

International Nuclear Information System (INIS)

Gajewski, J.J.; Jimenez, J.L.

1986-01-01

In order to examine the extent of bond making in the boat-like 3,3-sigmatropic shift transition states, trans-2,3-dimethyl-1,4-dimethylenecyclohexane (T) and its exomethylene tetradeuteria derivative (TXD) were prepared. The 3,3-shift of TXD at 305 0 C results in interconversion of starting material, 5,5,6,6-tetradeuterio-trans-2,3-dimethyl-1,4-dimethylene-cyclohexane (TND), and 2,2,3,3-tetradeuterio-anti-1,4-diethylidenecyclohexane (AD). A kinetic analysis of the first-order rate equations for the three-component system in both protio and deuterio species by numerical integration of the data and simplex minimization of the rate constants with symmetry and the assumption of no equilibrium or kinetic isotope effect on the TND-AD reaction gives a bond making kinetic isotope effect of 1/1.04 (0.04). The equilibrium isotope effects observed are 1/1.16 (0.04) so that the extent of bond formation in this boat-like bicyclo[2.2.2]octyl transition state is roughly 25%, a value to be compared with ca. 67% in chair-like acyclic 3,3-shift transition states. This rules out significant intervention of a bicyclo[2.2.2]octane-1,4-diyl intermediate or transition state. 30 references, 6 figures, 4 tables

Determination of dew absorption by coffee plant through deuterium concentrations in leaf water

Energy Technology Data Exchange (ETDEWEB)

Leopoldo, P R [Faculdade de Ciencias Medicas e Biologicas de Botucatu (Brazil); Salati, E; Matsui, E [Centro de Energia Nuclear na Agricultura, Piracicaba (Brazil)

1975-12-01

The effect of dew falling on leaves on the water metabolism of the coffee plant (Coffea arabica) is examined. The use of natural stable isotopes variations in plant physiological studies is demonstrated. Water extracted from leaf samples is analysed by mass spectrometry. Analyses of deuterium concentrations in water extracted from plant leaves, dew and nutrient solutions are made. Determination of changes in deuterium concentration in the water of leaves from plants exposed to dew, compared with leaves not exposed to dew, is carried out. Results show that during daytime there is an enrichment in deuterium in water contained in the leaves, while at night the opposite occurs.

Determination of dew absorption by coffee plant through deuterium concentrations in leaf water

International Nuclear Information System (INIS)

Leopoldo, P.R.; Salati, E.; Matsui, E.

1975-01-01

The effect of dew falling on leaves on the water metabolism of the coffee plant (Coffea arabica) is examined. The use of natural stable isotopes variations in plant physiological studies is demonstrated. Water extracted from leaf samples is analysed by mass spectrometry. Analyses of deuterium concentrations in water extracted from plant leaves, dew and nutrient solutions are made. Determination of changes in deuterium concentration in the water of leaves from plants exposed to dew, compared with leaves not exposed to dew, is carried out. Results show that during daytime there is an enrichment in deuterium in water contained in the leaves, while at night the opposite occurs [pt

[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].

Science.gov (United States)

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 (phydrogen 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 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 "plasmaisotopic composition, aimed at reducing the level of heavy non-radioactive atoms will allow the targeted nutritional correction of prooxidant-antioxidant status of the population in areas with adverse environmental conditions, stimulating by created isotopic D/H gradient cytoprotective mechanisms influencing the various components of nonspecific protection, including free radical oxidation processes. And then again, periodic assessment of the isotopic composition of nutrients will monitor the quality of food consumed by the population, and if

Aspartate beta-decarboxylase from Alcaligenes faecalis: carbon-13 kinetic isotope effect and deuterium exchange experiments

International Nuclear Information System (INIS)

Rosenberg, R.M.; O'Leary, M.H.

1985-01-01

The authors have measured the 13 C kinetic isotope effect at pH 4.0, 5.0, 6.0, and 6.5 and in D 2 O at pH 5.0 and the rate of D-H exchange of the alpha and beta protons of aspartic acid in D 2 O at pH 5.0 for the reaction catalyzed by the enzyme aspartate beta-decarboxylase from Alcaligenes faecalis. The 13 C kinetic isotope effect, with a value of 1.0099 +/- 0.0002 at pH 5.0, is less than the intrinsic isotope effect for the decarboxylation step, indicating that the decarboxylation step is not entirely rate limiting. The authors have been able to estimate probable values of the relative free energies of the transition states of the enzymatic reaction up to and including the decarboxylation step from the 13 C kinetic isotope effect and the rate of D-H exchange of alpha-H. The pH dependence of the kinetic isotope effect reflects the pKa of the pyridine nitrogen of the coenzyme pyridoxal 5'-phosphate but not that of the imine nitrogen. A mechanism is proposed for the exchange of aspartate beta-H that is consistent with the stereochemistry suggested earlier

Deuterium depleted water. Romanian achievements and prospects

International Nuclear Information System (INIS)

Stefanescu, Ioan; Steflea, Dumitru; Titescu, Gheorghe; Tamaian, Radu

2002-01-01

The deuterium depleted water (DDW) is microbiologically pure distilled water with a deuterium content lower than that of natural waters which amounts to 140 - 150 ppm D/(D+H); variations depend on geographical zone and altitude. The procedure of obtaining DDW is based on isotopic separation of natural water by vacuum distillation. Isotope concentration can be chosen within 20 to 120 ppm D/(D+H). The ICSI at Rm. Valcea has patented the procedure and equipment for the production of DDW. According to the document SF-01-2002/INC-DTCI - ICSI Rm. Valcea, the product has a D/(D+H) isotope concentration of 25 ± 5. Studies and research for finding the effects and methods of application in different fields were initiated and developed in collaboration with different institutes in Romania. The following important results obtained so far could be mentioned: - absence of toxicity upon organisms; - activation of vascular reactivity; - enhancement of defence capacity of the organism through non-specific immunity activation; - increase of salmonid reproduction capacity and enhancement of the adaptability of alevins to the environmental conditions; - radioprotective effect to ionizing radiation; - maintaining meat freshness through osmotic shock; - stimulation of growth of aquatic macrophytes; - enhancement of culture plant development in certain ontogenetic stages. Mostly, the results and practical applications of the research were patented and awarded with gold medals at international invention fairs. At present, research-development programmes are undergoing to find active biological features of DDW in fighting cancer, on one hand, and its applicability as food additive of pets or performing animals, on the other hand

Laser photochemical separation of hydrogen isotopes

International Nuclear Information System (INIS)

Fowler, M.C.

1979-01-01

A method of separating isotopes of hydrogen utilizing isotopically selective photodissociation of organic acid is disclosed. Specifically acetic or formic acid containing compounds of deuterated nd hydrogenated acid is irradiated by radiation having a wavelength in the infrared spectrum between 9.2 to 10.8 microns to produce deuterium hydroxide and deuterium hydride respectively. Maintaining the acid at an elevated temperature significantly improves the yield of isotope separation

Low temperature isotope effects of hydrogen diffusion in metallic glasses

International Nuclear Information System (INIS)

Hofmann, A.; Kronmueller, H.

1989-01-01

Snoek-like relaxation peaks of Hydrogen and Deuterium in amorphous Fe 80 B 20 , Fe 40 Ni 40 P 14 B 6 and Fe 91 Zr 9 are detected. At low H, D concentrations the peaks are near 200 K and show small isotope effects of the average activation energies (anti Q H ≅ 0.6 eV, anti Q D - anti Q H ≤ 10 meV). For higher H, D-contents the peaks shift to lower temperatures around to 120 K and show distinct isotope effects in the activation energies (anti Q H ≅ 0.3 eV, anti Q D - anti Q H ≅ 30 meV) and in the amplitude of the low temperature tails of the relaxation peaks. This points to isotope mass dependent deviations from the Arrhenius law due to nonthermal tunneling processes. (orig.)

Hydrogen isotope effect on storage behavior of U{sub 2}Ti and UZr{sub 2.3}

Energy Technology Data Exchange (ETDEWEB)

Jat, Ram Avtar; Sawant, S.G.; Rajan, M.B.; Dhanuskar, J.R. [Product Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kaity, Santu [Radiometallurgy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Parida, S.C., E-mail: sureshp@barc.gov.in [Product Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2013-11-15

U{sub 2}Ti and UZr{sub 2.3} alloys were prepared by arc melting method, vacuum annealed and characterized by XRD, SEM and EDX methods. Hydrogen isotope effect on the storage behavior of these alloys were studied by measuring the hydrogen/deuterium desorption pressure–composition–temperature (PCT) profiles in the temperature range of 573–678 K using a Sievert’s type volumetric apparatus. It was observed that, in the temperature and pressure range of investigation, all the isotherms show a single desorption plateau. The PCT data reveals that both U{sub 2}Ti and UZr{sub 2.3} alloys had normal isotope effects on hydrogen/deuterium desorption at all experimental temperatures. Thermodynamic parameters for dehydrogenation and dedeuteration reactions of the corresponding hydrides and deuterides of the above alloys were deduced from the PCT data.

Deuterium isotope shifts for backbone {sup 1}H, {sup 15}N and {sup 13}C nuclei in intrinsically disordered protein {alpha}-synuclein

Energy Technology Data Exchange (ETDEWEB)

Maltsev, Alexander S.; Ying Jinfa; Bax, Ad, E-mail: bax@nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

2012-10-15

Intrinsically disordered proteins (IDPs) are abundant in nature and characterization of their potential structural propensities remains a widely pursued but challenging task. Analysis of NMR secondary chemical shifts plays an important role in such studies, but the output of such analyses depends on the accuracy of reference random coil chemical shifts. Although uniform perdeuteration of IDPs can dramatically increase spectral resolution, a feature particularly important for the poorly dispersed IDP spectra, the impact of deuterium isotope shifts on random coil values has not yet been fully characterized. Very precise {sup 2}H isotope shift measurements for {sup 13}C{sup {alpha}}, {sup 13}C{sup {beta}}, {sup 13}C Prime , {sup 15}N, and {sup 1}H{sup N} have been obtained by using a mixed sample of protonated and uniformly perdeuterated {alpha}-synuclein, a protein with chemical shifts exceptionally close to random coil values. Decomposition of these isotope shifts into one-bond, two-bond and three-bond effects as well as intra- and sequential residue contributions shows that such an analysis, which ignores conformational dependence, is meaningful but does not fully describe the total isotope shift to within the precision of the measurements. Random coil {sup 2}H isotope shifts provide an important starting point for analysis of such shifts in structural terms in folded proteins, where they are known to depend strongly on local geometry.

Deuterium inventory in tungsten after plasma exposure. A microstructural survey

International Nuclear Information System (INIS)

Manhard, Armin

2012-09-01

Tungsten is a promising material for armouring the plasma-facing wall of future nuclear fusion experiments and power plants. It has a very high melting point, good thermal conductivity and is highly resistant against physical sputtering by energetic particles from the plasma. It also has a very low solubility for hydrogen isotopes. This is important both for safety and also for economic reasons, in particular with regard to the radioactive fusion fuel tritium. Due to this low solubility, the retention of hydrogen isotopes in tungsten materials after exposure to a plasma is dominated by the trapping of hydrogen isotopes at tungsten lattice defects. Therefore, a strong dependence of the hydrogen isotope retention on the microstructure of the tungsten is to be expected. This work describes a survey study of tungsten with different microstructures exposed to deuterium plasmas under a wide range of different plasma exposure conditions. The isotope deuterium was used because its natural abundance is much smaller than that of hydrogen (i.e., 1 H). This allows detecting even very small amounts retained in the tungsten practically without background signal. Furthermore, the use of deuterium allows utilising the nuclear reaction 2 D( 3 He,p) 4 He for depth-resolved quantification of the deuterium inventory up to depths of several microns. In order to standardise the specimens as far as possible, they were all cut from the same initial material from a single manufacturing batch. After a chemo-mechanical polishing procedure, which produces a well-defined surface, the specimens were annealed at either of four different temperatures in order to modify the grain structure and the dislocation density. These were then characterised by scanning electron microscopy and scanning transmission electron microscopy. The specimens were subsequently exposed in a fully characterised deuterium plasma source at different specimen temperatures, ion energies and deuterium fluences. In addition

Temperature-dependent transitions between normal and inverse isotope effects pertaining to the interaction of H-H and C-H bonds with transition metal centers.

Science.gov (United States)

Parkin, Gerard

2009-02-17

Deuterium kinetic isotope effects (KIEs) serve as versatile tools to infer details about reaction mechanisms and the nature of transition states, while equilibrium isotope effects (EIEs) associated with the site preferences of hydrogen and deuterium enable researchers to study aspects of molecular structure. Researchers typically interpret primary deuterium isotope effects based on two simple guidelines: (i) the KIE for an elementary reaction is normal (k(H)/k(D) > 1) and (ii) the EIE is dictated by deuterium preferring to be located in the site corresponding to the highest frequency oscillator. In this Account, we evaluate the applicability of these rules to the interactions of H-H and C-H bonds with a transition metal center. Significantly, experimental and computational studies question the predictability of primary EIEs in these systems based on the notion that deuterium prefers to occupy the highest frequency oscillator. In particular, the EIEs for (i) formation of sigma-complexes by coordination of H-H and C-H bonds and (ii) oxidative addition of dihydrogen exhibit unusual temperature dependencies, such that the same system may demonstrate both normal (i.e., K(H)/K(D) > 1) and inverse (i.e., K(H)/K(D) ZPE (where SYM is the symmetry factor, MMI is the mass-moment of inertia term, EXC is the excitation term, and ZPE is the zero-point energy term), and the distinctive temperature profile results from the inverse ZPE (enthalpy) and normal [SYM x MMI x EXC] (entropy) components opposing each other and having different temperature dependencies. At low temperatures, the ZPE component dominates and the EIE is inverse, while at high temperatures, the [SYM x MMI x EXC] component dominates and the EIE is normal. The inverse nature of the ZPE term is a consequence of the rotational and translational degrees of freedom of RH (R = H, CH(3)) becoming low-energy isotopically sensitive vibrations in the product, while the normal nature of the [SYM x MMI x EXC] component

Theoretical Study of H/D Isotope Effects on Nuclear Magnetic Shieldings Using an ab initio Multi-Component Molecular Orbital Method

Directory of Open Access Journals (Sweden)

Masanori Tachikawa

2013-05-01

Full Text Available We have theoretically analyzed the nuclear quantum effect on the nuclear magnetic shieldings for the intramolecular hydrogen-bonded systems of σ-hydroxy acyl aromatic species using the gauge-including atomic orbital technique combined with our multi-component density functional theory. The effect of H/D quantum nature for geometry and nuclear magnetic shielding changes are analyzed. Our study clearly demonstrated that the geometrical changes of hydrogen-bonds induced by H/D isotope effect (called geometrical isotope effect: GIE is the dominant factor of deuterium isotope effect on 13C chemical shift.

Cosmic Ray Deuterium from 0.2 to 3.0 GeV/nucleon

DEFF Research Database (Denmark)

Davis, A.J.; Labrador, A.W.; Mewaldt, R.A.

1996-01-01

The abundances of cosmic ray protons and deuterium between 0.2 and 3.0 GeV/nucleon were measured by the IMAX balloon--borne magnet spectrometer during a flight in July, 1992. These isotope measurements extend to significantly higher energies than have previously been achieved. A high--resolution ......The abundances of cosmic ray protons and deuterium between 0.2 and 3.0 GeV/nucleon were measured by the IMAX balloon--borne magnet spectrometer during a flight in July, 1992. These isotope measurements extend to significantly higher energies than have previously been achieved. A high...

Deuterium isotope fractionation between ortho-alkyl substituted phenols and t-butylthiol in oxygen bases

International Nuclear Information System (INIS)

Wawer, A.; Jelenska-Kazimierczuk, M.; Szydlowski, J.

1998-01-01

Equilibrium isotope effect in the exchange reaction of deuterium between phenol(P), 2-isopropyl phenol (IPP), 2,6-diisopropyl phenol (DIPP), 2,6-diterbutyl phenol (DTBP) and tertbutylthiol (TBT) has been studied in 296 K. The fractionation factors (α) have been measured in cyclohexane and carbon tetrachloride solutions and in a few oxygen bases: acetone, 1,4-dioxane, ethyl formate, ethyl ether, tetrahydrofurane, N,N-dimethylformamide, dimethylsulfoxide and hexamethylphosphoramide. Using chemical shifts of phenol OH protons, the thermodynamic parameters of complex formation with the oxygen bases have been determined. The experimental data show that lnα correlates with the formation enthalpy of the phenol-oxygen base complex in DIPP-TBT-base system but there is no simple correlation in IPP-TBT-base system. Furthermore, it was found that in DTBT-TBT-base system lnα depends linearly on the basicity of the solvent (DN parameters). On the other hand, lnα correlates with acidic parameters of the solvents (AN) in IPP-TBT-base and P-TBT-base systems. All above correlations are explained by taking into account two competition processes: self association of phenol molecules and their solvation by oxygen bases. (author)

Isotope effect on the zero point energy shift upon condensation

International Nuclear Information System (INIS)

Kornblum, Z.C.; Ishida, T.

1977-07-01

The various isotope-dependent and independent atomic and molecular properties that pertain to the isotopic difference between the zero point energy (ZPE) shifts upon condensation were derived. The theoretical development of the change of the ZPE associated with the internal molecular vibrations, due to the condensation of the gaseous molecules, is presented on the basis of Wolfsberg's second-order perturbation treatment of the isotope-dependent London dispersion forces between liquid molecules. The isotope effect on the ZPE shift is related to the difference between the sums of the integrated intensities of the infrared absorption bands of the two gaseous isotopic molecules. The effective atomic charges are also calculated from available experimental infrared intensity data. The effects of isotopic substitutions of carbon-13 for carbon-12 and/or deuterium for protium, in ethylene, methane, and the fluorinated methanes, CH 3 F, CH 2 F 2 , CHF 3 , and CF 4 , on the ZPE shift upon condensation are calculated. These results compare well with the Bigeleisen B-factors, which are experimentally obtained from vapor pressure measurements of the isotopic species. Each of the following molecular properties will tend to increase the isotopic difference between the ZPE shifts upon condensation: (1) large number of highly polar bonds, (2) high molecular weight, (3) non-polar (preferably) or massive molecule, (4) non-hydrogenous molecule, and (5) closely packed liquid molecules. These properties will result in stronger dispersion forces in the liquid phase between the lighter molecules than between the isotopically heavier molecules. 36 tables, 9 figures

Stable-isotope composition of the water of apple juice

International Nuclear Information System (INIS)

Bricout, Jacques; Merlivat, Liliane

1973-01-01

By deuterium and oxygen 18 analysis, it was shown that apples' water is enriched in heavier isotopes as compared to rain water. The isotopic composition of the water of reconstituted apple juice is closed to the isotopic content of the rain water used for dilution. Thus, deuterium and oxyden 18 analysis allows a good analytical distinction between natural apple juice and reconstituted juices [fr

Measurement of the deuterium concentration in water samples using a CW chemical deuterium fluoride laser

International Nuclear Information System (INIS)

Trautmann, M.

1979-10-01

In this study a new method for the determination of the deuterium content in water samples is described. The absorption of the radiation of a CW deuterium fluoride laser by the isotope HDO in the water vapor of the sample is measured by means of an optoacoustic detector (spectrophone). Thereby advantage is taken of the fact that H 2 O hardly absorbs the laser radiation and that D 2 O only exists in negligible concentrations. The isotope ratio of hydrogen can be calculated from the measured relative concentration of HDO. In the course of this investigation the relative absorption cross sections of HDO for the different laser lines were determined. It was thereby established that there exists a very good coincidence of an HDO absorption line with the 2P2 laser line. Using a very sensitive nonresonant spectrophone the relative concentration of HDO in natural water samples could be determined with an accuracy of about 10%. The experiments also demonstrated that with appropriate improvements made to the apparatus and using a second spectrophone as a reference it should be possible to increase this accuracy to 0,1%. (orig.)

Anomalous H/D isotope effect on 35Cl NQR frequencies and H/D isotope effect on 1H MAS NMR spectra in pyrrolidinium p-chlorobenzoate

International Nuclear Information System (INIS)

Nakano, Ryo; Honda, Hisashi; Nakata, Eiichi; Takamizawa, Satoshi; Noro, Sumiko; Kimura, Taiki; Kyo, Shin-shin; Ishimaru, Shin'ichi; Miyake, Ryosuke

2010-01-01

An anomalous isotope effect was observed in the 35 Cl NQR frequency of pyrrolidinium p-chlorobenzoate (C 4 H 8 NH 2 + ·ClC 6 H 4 COO - ) by deuterium substitution of hydrogen atoms which form two kinds of N-H...O type hydrogen bonds. Large negative frequency shifts of the 35 Cl resonance lines, reaching 309 kHz at 77 K and 267 kHz at 293 K, were obtained upon deuteration, although the Cl atom in the molecule formed no hydrogen bonds in the crystal. 1 H MAS NMR lines showed significant changes by the deuterium substitution, while in contrast, small shifts of 13 C CP/MAS NMR signals were obtained. Our measurements of 1 H NMR spin-lattice relaxation times (T 1 ) suggested that the H/D isotope shifts detected from the 35 Cl NQR frequencies and 1 H NMR spectra are due to structural changes rather than molecular dynamics. Single-crystal X-ray diffraction measurements showed two remarkable H/D isotope differences in the molecular arrangements, (1) the N-H length along the crystallographic a axis became 1 pm shorter, and (2) the dihedral angle between benzene and the pyrrolidine ring changed by 1.1(2)deg upon deuteration. Using density functional theory estimations, the anomalous 35 Cl NQR frequency shifts and 1 H MAS NMR line-shape changes could be explained by the dihedral angle change rather than the N-H length difference. (author)

Atmospheric influence on the deuterium excess signal in polar firn - implications for ice core interpretation

NARCIS (Netherlands)

Schlosser, Elisabeth; Oerter, H.; Masson-Delmotte, V.; Reijmer, C.H.

2008-01-01

The seasonal deuterium excess signal of fresh snow samples from Neumayer station, coastal Dronning Maud Land, Antarctica, was studied to investigate the relationship between deuterium excess and precipitation origin. An isotope model was combined with a trajectory model to determine the relative

The use of deuterium in medicine

International Nuclear Information System (INIS)

Roth, E.; Sutton, J.; Marsac, J.

1981-03-01

Whenever a corporal function experiences a disturbance reflected either by changes in metabolic activity or modifications of the importance of pools of certain molecules the possibility exists of making use of isotopes in diagnosis. This paper discusses the use of deuterium to measure total body water and extravascular water in the lungs, and gives examples of clinical applications

Hydrogen isotopic substitution experiments in nanostructured porous silicon

International Nuclear Information System (INIS)

Palacios, W.D.; Koropecki, R.R.; Arce, R.D.; Busso, A.

2008-01-01

Nanostructured porous silicon is usually prepared by electrochemical anodization of monocrystalline silicon using a fluorine-rich electrolyte. As a result of this process, the silicon atoms conserve their original crystalline location, and many of the dangling bonds appearing on the surface of the nanostructure are saturated by hydrogen coming from the electrolyte. This work presents an IR study of the effects produced by partial substitution of water in the electrolytic solution by deuterium oxide. The isotopic effects on the IR spectra are analyzed for the as-prepared samples and for the samples subjected to partial thermal effusion of hydrogen and deuterium. We demonstrate that, although deuterium is chemically indistinguishable from hydrogen, it presents a singular behaviour when used in porous silicon preparation. We found that deuterium preferentially bonds forming Si-DH groups. A possible explanation of the phenomenon is presented, based on the different diffusivities of hydrogen and deuterium

Hydrogen isotopic substitution experiments in nanostructured porous silicon

Energy Technology Data Exchange (ETDEWEB)

Palacios, W.D. [Facultad de Ciencias Exactas y Naturales y Agrimensura - (UNNE), Avenida Libertad 5500, 3400 Corrientes (Argentina); Koropecki, R.R. [INTEC (CONICET-UNL), Gueemes 3450, 3000 Santa Fe (Argentina)], E-mail: rkoro@intec.ceride.gov.ar; Arce, R.D. [INTEC (CONICET-UNL), Gueemes 3450, 3000 Santa Fe (Argentina); Busso, A. [Facultad de Ciencias Exactas y Naturales y Agrimensura - (UNNE), Avenida Libertad 5500, 3400 Corrientes (Argentina)

2008-04-30

Nanostructured porous silicon is usually prepared by electrochemical anodization of monocrystalline silicon using a fluorine-rich electrolyte. As a result of this process, the silicon atoms conserve their original crystalline location, and many of the dangling bonds appearing on the surface of the nanostructure are saturated by hydrogen coming from the electrolyte. This work presents an IR study of the effects produced by partial substitution of water in the electrolytic solution by deuterium oxide. The isotopic effects on the IR spectra are analyzed for the as-prepared samples and for the samples subjected to partial thermal effusion of hydrogen and deuterium. We demonstrate that, although deuterium is chemically indistinguishable from hydrogen, it presents a singular behaviour when used in porous silicon preparation. We found that deuterium preferentially bonds forming Si-DH groups. A possible explanation of the phenomenon is presented, based on the different diffusivities of hydrogen and deuterium.

High resolution deuterium NMR studies of bacterial metabolism

Energy Technology Data Exchange (ETDEWEB)

Aguayo, J.B.; Gamcsik, M.P.; Dick, J.D.

1988-12-25

High resolution deuterium NMR spectra were obtained from suspensions of five bacterial strains: Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus. Deuterium-labeled D-glucose at C-1, C-2, and C-6 was used to monitor dynamically anaerobic metabolism. The flux of glucose through the various bacterial metabolic pathways could be determined by following the disappearance of glucose and the appearance of the major end products in the 2H NMR spectrum. The presence of both labeled and unlabeled metabolites could be detected using 1H NMR spectroscopy since the proton resonances in the labeled species are shifted upfield due to an isotopic chemical shift effect. The 1H-1H scalar coupling observed in both the 2H and 1H NMR spectra was used to assign definitively the resonances of labeled species. An increase in the intensity of natural abundance deuterium signal of water can be used to monitor pathways in which a deuteron is lost from the labeled metabolite. The steps in which label loss can occur are outlined, and the influence these processes have on the ability of 2H NMR spectroscopy to monitor metabolism are assessed.

High resolution deuterium NMR studies of bacterial metabolism

International Nuclear Information System (INIS)

Aguayo, J.B.; Gamcsik, M.P.; Dick, J.D.

1988-01-01

High resolution deuterium NMR spectra were obtained from suspensions of five bacterial strains: Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus. Deuterium-labeled D-glucose at C-1, C-2, and C-6 was used to monitor dynamically anaerobic metabolism. The flux of glucose through the various bacterial metabolic pathways could be determined by following the disappearance of glucose and the appearance of the major end products in the 2H NMR spectrum. The presence of both labeled and unlabeled metabolites could be detected using 1H NMR spectroscopy since the proton resonances in the labeled species are shifted upfield due to an isotopic chemical shift effect. The 1H-1H scalar coupling observed in both the 2H and 1H NMR spectra was used to assign definitively the resonances of labeled species. An increase in the intensity of natural abundance deuterium signal of water can be used to monitor pathways in which a deuteron is lost from the labeled metabolite. The steps in which label loss can occur are outlined, and the influence these processes have on the ability of 2H NMR spectroscopy to monitor metabolism are assessed

Deuterium Depth Profile in Neutron-Irradiated Tungsten Exposed to Plasma

International Nuclear Information System (INIS)

Shimada, Masashi; Cao, G.; Hatano, Y.; Oda, T.; Oya, Y.; Hara, M.; Calderoni, P.

2011-01-01

The effect of radiation damage has been mainly simulated using high-energy ion bombardment. The ions, however, are limited in range to only a few microns into the surface. Hence, some uncertainty remains about the increase of trapping at radiation damage produced by 14 MeV fusion neutrons, which penetrate much farther into the bulk material. With the Japan-US joint research project: Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), the tungsten samples (99.99 % pure from A.L.M.T., 6mm in diameter, 0.2mm in thickness) were irradiated to high flux neutrons at 50 C and to 0.025 dpa in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). Subsequently, the neutron-irradiated tungsten samples were exposed to a high-flux deuterium plasma (ion flux: 1021-1022 m-2s-1, ion fluence: 1025-1026 m-2) in the Tritium Plasma Experiment (TPE) at the Idaho National Laboratory (INL). First results of deuterium retention in neutron-irradiated tungsten exposed in TPE have been reported previously. This paper presents the latest results in our on-going work of deuterium depth profiling in neutron-irradiated tungsten via nuclear reaction analysis. The experimental data is compared with the result from non neutron-irradiated tungsten, and is analyzed with the Tritium Migration Analysis Program (TMAP) to elucidate the hydrogen isotope behavior such as retention and depth distribution in neutron-irradiated and non neutron-irradiated tungsten.

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

Science.gov (United States)

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.

Quantum tunneling observed without its characteristic large kinetic isotope effects.

Science.gov (United States)

Hama, Tetsuya; Ueta, Hirokazu; Kouchi, Akira; Watanabe, Naoki

2015-06-16

Classical transition-state theory is fundamental to describing chemical kinetics; however, quantum tunneling is also important in explaining the unexpectedly large reaction efficiencies observed in many chemical systems. Tunneling is often indicated by anomalously large kinetic isotope effects (KIEs), because a particle's ability to tunnel decreases significantly with its increasing mass. Here we experimentally demonstrate that cold hydrogen (H) and deuterium (D) atoms can add to solid benzene by tunneling; however, the observed H/D KIE was very small (1-1.5) despite the large intrinsic H/D KIE of tunneling (≳ 100). This strong reduction is due to the chemical kinetics being controlled not by tunneling but by the surface diffusion of the H/D atoms, a process not greatly affected by the isotope type. Because tunneling need not be accompanied by a large KIE in surface and interfacial chemical systems, it might be overlooked in other systems such as aerosols or enzymes. Our results suggest that surface tunneling reactions on interstellar dust may contribute to the deuteration of interstellar aromatic and aliphatic hydrocarbons, which could represent a major source of the deuterium enrichment observed in carbonaceous meteorites and interplanetary dust particles. These findings could improve our understanding of interstellar physicochemical processes, including those during the formation of the solar system.

Isotope effect on the zero point energy shift upon condensation

International Nuclear Information System (INIS)

Kornblum, Z.C.

1977-01-01

The various isotope-dependent and independent atomic and molecular properties that pertain to the isotopic difference between the zero point energy (ZPE) shifts upon condensation have been derived. The theoretical development of the change of the ZPE associated with the internal molecular vibrations, due to the condensation of the gaseous molecules, has been presented on the basis of Wolfsberg's second-order perturbation treatment of the isotope-dependent London dispersion forces between liquid molecules. The isotope effect on the ZPE shift is related to the difference between the sums of the integrated intensities of the infrared absorption bands of the two gaseous isotopic molecules. Each intensity sum is expressed, in part, in terms of partial derivatives of the molecular dipole moment with respect to atomic cartesian coordinates. These derivatives are related to the isotope-independent effective charges of the atoms, which are theoretically calculated by means of a modified CNDO/2 computer program. The effective atomic charges are also calculated from available experimental infrared intensity data. The effects of isotopic substitutions of carbon-13 for carbon-12 and/or deuterium for protium, in ethylene, methane, and the fluorinated methanes, CH 3 F, CH 2 F 2 , CHF 3 , and CF 4 , on the ZPE shift upon condensation are calculated. These results compare well with the Bigeleisen B-factors, which are experimentally obtained from vapor pressure measurements of the isotopic species. Each of the following molecular properties will tend to increase the isotopic difference between the ZPE shifts upon condensation: (1) large number of highly polar bonds, (2) high molecular weight, (3) non-polar (preferably) or massive molecule, (4) non-hydrogenous molecule, and (5) closely packed liquid molecules. These properties will result in stronger dispersion forces in the liquid phase between the lighter molecules than between the isotopically heavier molecules

Determination of the Tautomeric Equilibria of Pyridoyl Benzoyl -Diketones in the Liquid and Solid State through the use of Deuterium Isotope Effects on 1H and 13C NMR Chemical Shifts and Spin Coupling Constants

DEFF Research Database (Denmark)

Hansen, Poul Erik; Borisov, Eugeny V.; Lindon, John C.

2015-01-01

The tautomeric equilibria for 2-pyridoyl-, 3-pyridoyl-, and 4-pyridoyl-benzoyl methane have been investigated using deuterium isotope effects on 1H and 13C chemical shifts both in the liquid and the solid state. Equilibria are established both in the liquid and the solid state. In addition......, in the solution state the 2-bond and 3-bond J(1H–13C) coupling constants have been used to confirm the equilibrium positions. The isotope effects due to deuteriation at the OH position are shown to be superior to chemical shift in determination of equilibrium positions of these almost symmetrical -pyridoyl......-benzoyl methanes. The assignments of the NMR spectra are supported by calculations of the chemical shifts at the DFT level. The equilibrium positions are shown to be different in the liquid and the solid state. In the liquid state the 4-pyridoyl derivative is at the B-form (C-1 is OH), whereas the 2-and 3-pyridoyl...

Stable isotopic characteristic of Taiwan's precipitation: A case study of western Pacific monsoon region

Science.gov (United States)

Peng, Tsung-Ren; Wang, Chung-Ho; Huang, Chi-Chao; Fei, Li-Yuan; Chen, Chen-Tung Arthur; Hwong, Jeen-Lian

2010-01-01

The stable oxygen and hydrogen isotopic features of precipitation in Taiwan, an island located at the western Pacific monsoon area, are presented from nearly 3,500 samples collected during the past decade for 20 stations. Results demonstrate that moisture sources from diverse air masses with different isotopic signals are the main parameter in controlling the precipitation's isotope characteristics. The air mass from polar continental (Pc) region contributes the precipitation with high deuterium excess values (up to 23‰) and relatively enriched isotope compositions (e.g., - 3.2‰ for δ 18O) during the winter with prevailing northeasterly monsoon. By contrast, air masses from equatorial maritime (Em) and tropical maritime (Tm) supply the precipitation with low deuterium excess values (as low as about 7‰) and more depleted isotope values (e.g., - 8.9‰ and - 6.0‰ for δ 18O of Tm and Em, respectively) during the summer with prevailing southwesterly monsoon. Thus seasonal differences in terms of δ 18O, δD, and deuterium excess values are primarily influenced by the interactions among various precipitation sources. While these various air masses travel through Taiwan, secondary evaporation effects further modify the isotope characteristics of the inland precipitation, such as raindrop evaporation (reduces the deuterium excess of winter precipitation) and moisture recycling (increases the deuterium excess of summer precipitation). The semi-quantitative estimations in terms of evaluation for changes in the deuterium excess suggest that the raindrop evaporation fractions for winter precipitation range 7% to 15% and the proportions of recycling moisture in summer precipitation are less than 5%. Additionally, the isotopic altitude gradient in terms of δ 18O for summer precipitation is - 0.22‰/100 m, greater than - 0.17‰/100 m of winter precipitation. The greater isotopic gradient in summer can be attributed to a higher temperature vs. altitude gradient

Origin of excess heat generated during loading Pd-impregnated alumina powder with deuterium and hydrogen

International Nuclear Information System (INIS)

Dmitriyeva, O.; Cantwell, R.; McConnell, M.; Moddel, G.

2012-01-01

Highlights: ► We studied heat produced by hydrogen and deuterium in Pd-impregnated alumina powder. ► Samples were fabricated using light and heavy water isotopes and varied the gas used for loading. ► Incorporation of hydrogen and deuterium influenced the amount of heat released or consumed. ► Pd nanoparticles appear to catalyze hydrogen/deuterium (H/D) exchange chemical reactions. ► Anomalous heating can be accounted for by chemical rather than nuclear reactions. - Abstract: We studied heat production in Pd-impregnated alumina powder in the presence of hydrogen and deuterium gases, investigating claims of anomalous heat generated as a result of nuclear fusion, usually referred to as a low energy nuclear reaction (LENR). By selecting the water isotope used to fabricate the material and then varying the gas used for loading, we were able to influence the amount of heat released or consumed. We suggest that Pd in its nanoparticle form catalyzes hydrogen/deuterium (H/D) exchange reactions in the material. This hypothesis is supported by heat measurements, residual gas analysis (RGA) data, and calculations of energy available from H/D exchange reactions. Based on the results we conclude that the origin of the anomalous heat generated during deuterium loading of Pd-enriched alumina powder is chemical rather than nuclear.

Process for the separation of deuterium and tritium from water using ammonia and a hydrogen-nitrogen-mixture

International Nuclear Information System (INIS)

Mandrin, Ch.

1986-01-01

A multistage process for separation of deuterium and tritium from water using ammonia and a hydrogen-nitrogen mixture. In a first stage isotopic exchange takes place between water containing deuterium and tritium, and ammonia depleted in deuterium and tritium. The molar ammonia throughput is chosen to be greater than two third of the molar throughput of water. The advantage of the process consists in the fact that the main product is water almost entirely free from deuterium and tritium. The byproducts are compounds enriched in deuterium and tritium, and nitrogen enriched in N-15

Deuterium and oxygen-18 abundance in birds: Implications for DLW energetics studies

International Nuclear Information System (INIS)

Tatner, P.

1990-01-01

The doubly labeled water (DLW) technique for measuring energy expenditure may employ one ( 18 O) or two ( 18 O and deuterium) stable isotopes as tracers. These occur naturally in the environment, so when they are used as tracers it is necessary to subtract the background levels. Few studies report data on background concentrations. This work provides such data for a range of avian species. Overall, there was a strong positive correlation (r = 0.63) between the 18 O and deuterium concentrations in birds' body water. Variation in the deuterium concentration was less extensive than in the 18 O concentration (1:2.7 parts/million). In the European robin, there was a linked, seasonal variation in 18 O and deuterium abundance producing high summer and low winter values. Throughout the year, a high individual variability was greater in 18 O than in deuterium. A difference between the European robin and the dipper suggests that habitat may also influence background abundance. Investigation of the effect of variation in background abundance on measures of energy expenditure for small passerines (20 g) revealed that employing estimates, instead of direct measurements, had a minor influence over an experimental period of 1 day but could potentially introduce errors as large as 54% over a 2-day period

Stable isotopes labelled compounds

International Nuclear Information System (INIS)

1982-09-01

The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

Deuterium in astrophysical ice analogues: Isotope exchange and IR detection sensitivity for HDO

Science.gov (United States)

Escribano, R. M.; Galvez, O.; Mate, B.; Herrero, V. J.

2011-12-01

Among D-bearing molecules, water is especially interesting from an astrophysical point of view. Although the deuterium content of water in astronomical environments is relatively small as compared with other molecules, it holds most valuable information, still largely undeciphered, on the dynamics of formation and evaporation of ice grain mantels in protostellar regions [1], and is crucial for the understanding of the formation of the Solar System and the Earth [2]. In this work, we have used the OD stretching bands of HDO and D2O molecules in various ice mixtures formed by vapor deposition on a cold substrate (see ref [3] for a description of the experimental set-up) to study the sensitivity of the IR technique for the detection of HDO in ice samples, and to monitor processes of H/D isotope exchange in these solids. It is found that the detection sensitivity is strongly dependent on the ice structure. The OD band is extremely broad and tends to disappear into the absorption continuum of H2O for low temperature amorphous samples. Detectable HDO/H2O ratios with this technique may range from a few per cent for amorphous samples to a few per thousand in crystalline ice. These relatively high upper limits and the appreciable dependence of the band shape on temperature, complicating the interpretation of data from many lines of sight, may question the usefulness of this technique. Isotopic H/D exchange in mixed ices of H2O/D2O is found to start at ~ 120 K and is greatly accelerated at 150 K, as crystallization proceeds in the ice. The process is mainly driven by proton transfer assisted by orientational defect mobility. Annealed amorphous samples are more favourable for isotope exchange than samples directly formed in the crystalline phase. The annealing process seems to lead to polycrystalline ice morphology with a higher defect activity. The present data emphasize the relevance of a depletion mechanism for D atoms in hydroxylic bonds in the solid state, recently

Deuterium trapping in carbon fiber composites under high fluence

International Nuclear Information System (INIS)

Airapetov, A.A.; Begrambekov, L.B.; Kuzmin, A.A.; Shigin, P.A.; Zakharov, A.M.

2010-01-01

The paper is devoted to investigation of deuterium trapping in CFC, dance graphite MPG-8 and pyrolytic graphite (PG) under plasma ion- and electron irradiation. Number of specific features of deuterium trapping and retention under plasma ion and electron irradiation is presented and discussed. In particular it is shown that 1) deuterium trapping takes place even when energy of impinging ions approaches zero; 2) deuterium is trapped under irradiation by plasma electrons; 3) under irradiation at equal fluences deuterium trapping is higher, when ion flux is smaller. High energy ion penetrating the surfaces are trapped in the traps created at the expense of their kinetic energy. The process may be named 'kinetic trapping'. Under low energy (smaller than 200 eV) electron and/or ion irradiation the energy of inelastic interaction on the surface provides creation of active centers, which initiate dissociation of deuterium sorbed on the surface, penetration of deuterium atoms into graphite and their trapping in specific low energy traps. The term 'potential trapping' is proposed for this type of trapping. Under high energy irradiation such atoms can fill the traps formed through kinetic mechanism. Origination of moveable deuterium atoms from the layer of surface sorption seems to be time dependent process and it is a reason of increase of trapping along with irradiation time. New features of deuterium trapping and retention in graphite evaluated in this study offer new opportunities for analysis and correct estimation of hydrogen isotope trapping and retention in tokamaks having graphite tiles. (authors)

Analysis of hydrogen-deuterium mixtures and of mixtures of heavy-water and light-water by means of a mass spectrometer; Analyse des melanges hydrogene-deuterium et des melanges d'eau lourde et d'eau legere au moyen du spectrometre de masse

Energy Technology Data Exchange (ETDEWEB)

Chenouard, J; Gueron, J; Roth, E

1951-07-01

The differences between hydrogen and deuterium with respect to the capture of thermal neutrons (hydrogen = 0.31 barn; deuterium 0.00065 barn) explains the interest of detecting small variations of the isotopic composition of the heavy waters used in the Chatillon nuclear pile. The aim of this report is to describe and discuss the method used since more than a year for the dosimetry of heavy waters. After a recall of the principle of mass spectroscopy analysis of deuterium-hydrogen mixtures, the preciseness of the results is presented and the balancing method used for the determination of the isotopic composition of hydrogen-deuterium mixtures is explained in detail. Finally, a brief comparison of the preciseness of mass spectroscopy measurements with the analyses made with other methods is performed. Some calculations and the tables of results are presented in appendixes. (J.S.)

Isotope effects on chemical shifts in tautomeric systems with double proton transfer. Citronin

International Nuclear Information System (INIS)

Hansen, P.E.; Langgard, M.; Bolvig, S.

1998-01-01

Primary and secondary deuterium isotope effects on 1 H and 13 C chemical shifts are measured in citrinin, a tautomeric compound with an unusual doubly intramolecularly hydrogen bonded structure. The isotope effects are to a large extent dominated by equilibrium contributions and deuteration leads to more of the deuterated enol forms rather than the deuterated acid form. 1 H 13 C and 17 O nuclear shieldings are calculated using density functional ab initio methods. A very good correlation between calculated nuclear shieldings and experimental 1 H and 13 C chemical shifts is obtained. The tautomeric equilibrium can be analyzed based on the isotope effects on B-6 and C-8 carbons and shows an increase in the o-quinone form on lowering the temperature. Furthermore, upon deuteration the largest equilibrium shift is found for deuteration at OH-8 and the shift in the tautomeric equilibrium upon deuteration at OH-8 and the shift in the tautomeric equilibrium upon deuteration is increasing at lower temperature. (author)

Mechanistic deductions from kinetic isotope effects and pH studies of pyridoxal phosphate dependent carbon-carbon lyases: Erwinia herbicola and Citrobacter freundii tyrosine phenol-lyase

International Nuclear Information System (INIS)

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

1988-01-01

The pH dependence of the kinetic parameters and primary deuterium isotope effects have been determined for tyrosine phenol-lyase from both Erwinia herbicola and Citrobacter freundii. The primary deuterium isotope effects indicate that proton abstraction from the 2-position of the substrate is partially rate-limiting for both enzymes. The C. freundii enzyme primary deuterium isotope effects [DV = 3.5 and D(V/Ktyr) = 2.5] are pH independent, indicating that tyrosine is not sticky (i.e., does not dissociate slower than it reacts to give products). Since Vmax for both tyrosine and the alternate substrate S-methyl-L-cysteine is also pH independent, substrate binds only to the correctly protonated form of the enzyme. For the E. herbicola enzyme, both Vmax and V/K for tyrosine or S-methyl-L-cysteine are pH dependent, as well as both DV and D(V/Ktyr). Thus, while both the protonated and unprotonated enzyme can bind substrate, and may be interconverted directly, only the unprotonated Michaelis complex is catalytically competent. At pH 9.5, DV = 2.5 and D(V/Ktyr) = 1.5. However, at pH 6.4 the isotope effect on both parameters is equal to 4.1. From these data, the forward commitment factor (cf = 5.2) and catalytic ratio (cvf = 1.1) for tyrosine and S-methyl-L-cysteine (cf = 2.2, cvf = 24) are calculated. Also, the Michaelis complex partition ratio (cf/cvf) for substrate and products is calculated to be 4.7 for tyrosine and 0.1 for S-methyl-L-cysteine

Kinetic isotope effects in the CH4 + H→CH3 + H2 system. Predictions of the LMR six-body potential-energy reaction hypersurface

International Nuclear Information System (INIS)

Marriott, T.D.

1976-01-01

Scope of Study: The purpose of this study was two-fold. First, it served to test, in part, the usefulness of the LMR six-body potential-energy surface (LMR-PES) for transition-state theory predictions of the kinetic isotope effects for both the forward and reverse reactions of CH 4 + H reversible CH 3 + H 2 . In this regard the agreement between experimental and theoretical isotope effects, assuming the former to be accurate, provides information about the accuracy of the curvature of the potential energy surface for motion both parallel and perpendicular to the reaction coordinate. Second, these isotope effects were used to assess the validity of a number of qualitative and semi-quantitative interpretations of kinetic isotope effects developed in physical organic chemistry with regard to this reaction system. The force constants and geometries obtained numerically from the LMR-PES were found to produce reasonable harmonic approximations to the reactant normal mode frequencies. Neglecting tunneling, the LMR-PES reasonably reproduces the experimental k/sub H//k/sub D/ values for the reactions CH 4 + H(D), CH 3 + HD(DH) and CD 2 + HD(DH). Since previous theoretical treatments of primary deuterium kinetic isotope effects have neglected the bending normal mode frequencies, a semi-quantitative study of the effect of neglecting bending frequencies on the VP, EXC, and ZPE elements as well as the transition-state theory kinetic isotope effects was performed. The Swain-Schaad relationship between primary deuterium and tritium kinetic isotope effects was shown to hold to a reasonable degree of accuracy for the LMR-PES reaction system. A relationship between 13-carbon and 14-carbon kinetic isotope effects similar to the Swain-Schaad relationship was derived

Isotope effects in the non enzymic glycation of hemoglobin catalyzed by DPG

International Nuclear Information System (INIS)

Gil, Herminia; Uzcategui, Jorge

1993-01-01

The paradigmatic reaction of glucose with hemoglobin (Hb A o ) has been studied and is known to occur most rapidly at the N-terminal valine of the β-subunit. An initial, rapid imine formation is succeeded by slower Amadori rearrangement. Non enzymic glycation of Hb A o was studied in vitro in buffer Tris 10 mM in H 2 O and D 2 O, pH 7.3, pD 7.8 at 37 deg C at a fixed concentration of 2,3 diphosphoglycerate (DPG). The reaction exhibits identical rates in protium and deuterium oxides. When D-glucose-2-h is compared with D-glucose-2-d, the kinetic isotope effect for the DPG-dependent rate is 2.1 ± 0.3, while the DPG-independent rate constant shows no isotope effect (1.1 ± 0.1). The absence of a rate in isotopic water solvents shows that proton donation for solvent, lyons or DPG does not limit the rate. The substrate isotope effect of around 2 for the DPG kinetic term indicates that the proton abstraction step of the Amadori rearrangement by DPG is wholly or partially rate-limiting for this reaction. (author)

Origin of excess heat generated during loading Pd-impregnated alumina powder with deuterium and hydrogen

Energy Technology Data Exchange (ETDEWEB)

Dmitriyeva, O., E-mail: olga.dmitriyeva@colorado.edu [Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309-0425 (United States); Coolescence LLC, 2450 Central Ave Ste F, Boulder, CO 80301 (United States); Cantwell, R.; McConnell, M. [Coolescence LLC, 2450 Central Ave Ste F, Boulder, CO 80301 (United States); Moddel, G. [Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309-0425 (United States)

2012-09-10

Highlights: Black-Right-Pointing-Pointer We studied heat produced by hydrogen and deuterium in Pd-impregnated alumina powder. Black-Right-Pointing-Pointer Samples were fabricated using light and heavy water isotopes and varied the gas used for loading. Black-Right-Pointing-Pointer Incorporation of hydrogen and deuterium influenced the amount of heat released or consumed. Black-Right-Pointing-Pointer Pd nanoparticles appear to catalyze hydrogen/deuterium (H/D) exchange chemical reactions. Black-Right-Pointing-Pointer Anomalous heating can be accounted for by chemical rather than nuclear reactions. - Abstract: We studied heat production in Pd-impregnated alumina powder in the presence of hydrogen and deuterium gases, investigating claims of anomalous heat generated as a result of nuclear fusion, usually referred to as a low energy nuclear reaction (LENR). By selecting the water isotope used to fabricate the material and then varying the gas used for loading, we were able to influence the amount of heat released or consumed. We suggest that Pd in its nanoparticle form catalyzes hydrogen/deuterium (H/D) exchange reactions in the material. This hypothesis is supported by heat measurements, residual gas analysis (RGA) data, and calculations of energy available from H/D exchange reactions. Based on the results we conclude that the origin of the anomalous heat generated during deuterium loading of Pd-enriched alumina powder is chemical rather than nuclear.

Effect of noble gas ion pre-irradiation on deuterium retention in tungsten

NARCIS (Netherlands)

Cheng, L.; Zhao, Z. H.; De Temmerman, G.; Yuan, Y.; Morgan, T. W.; Guo, L. P.; Wang, B.; Zhang, Y.; Wang, B. Y.; Zhang, P.; Cao, X. Z.; Lu, G. H.

2016-01-01

Impurity seeding of noble gases is an effective way of decreasing the heat loads onto the divertor targets in fusion devices. To investigate the effect of noble gases on deuterium retention, tungsten targets have been implanted by different noble gas ions and subsequently exposed to deuterium

Tritium conductivity and isotope effect in proton-conducting perovskites

International Nuclear Information System (INIS)

Mukundan, R.; Brosha, E.L.; Birdsell, S.A.; Costello, A.L.; Garzon, F.H.; Willms, R.S.

1999-01-01

The tritium ion conductivities of SrZr 0.9 Yb 0.1 O 2.95 and BaCe 0.9 Yb 0.1 O 2.95 have been measured by ac impedance analysis. The high tritium conductivity of these perovskites could potentially lead to their application as an electrochemical membrane for the recovery of tritium from tritiated gas streams. The conductivities of these perovskites, along with SrCe 0.95 Yb 0.05 O 2.975 , were also measured in hydrogen- and deuterium-containing atmospheres to illustrate the isotope effect. For the strontium zirconate and barium cerate samples, the impedance plot consists of two clearly resolved arcs, a bulk and a grain boundary arc, in the temperature range 50--350 C. However, for the strontium cerate sample, the clear resolution of the bulk conductivity was not possible and only the total conductivity was measurable. Thus, the isotope effect was clearly established only for the strontium zirconate and barium cerate samples. The decrease in bulk conductivity with increasing isotope mass was found to be a result of an increase in the activation energy for conduction accompanied by a decrease in the pre-exponential factor. Since the concentration of the mobile species (H+, D+, or T+) should remain relatively constant at T < 350 C, this increase in activation energy is directly attributable to the increased activation energy for the isotope mobility

Use of water stable isotopes in climatology and paleoclimatology illustrated from polar ice cores studies

International Nuclear Information System (INIS)

Jouzel, J.; Lorius, C.

1994-01-01

The isotopic content of ancient waters (deuterium and oxygen 18) gives a key access to past climatic changes. An essentially linear relationship exists between the isotopic content of a precipitation and the temperature of the site (at least for medium and high latitudes). This link between water isotope atmospheric cycle and climate is presented through various isotopic models and illustrated from the deuterium profile obtained along the Vostok ice core in East Antarctica. This 2 km record which covers a full glacial-interglacial cycle (160000 years) confirms the existence of a link between insolation changes and climate (Milankovitch theory). It shows also that the greenhouse effect has played a role in glacial-interglacial changes in amplifying this orbital forcing. (authors). 10 figs., 23 refs

Influence of tungsten microstructure and ion flux on deuterium plasma-induced surface modifications and deuterium retention

Energy Technology Data Exchange (ETDEWEB)

Buzi, Luxherta [IEK - Plasmaphysik, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Juelich (Germany); FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research (Netherlands); Ghent University (Belgium); Temmerman, Greg de [FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research (Netherlands); Reinhart, Michael; Matveev, Dmitry; Unterberg, Bernhard; Wienhold, Peter; Breuer, Uwe; Kreter, Arkadi [IEK - Plasmaphysik, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Juelich (Germany); Oost, Guido van [Ghent University (Belgium)

2014-07-01

Tungsten is to be used as plasma-facing material for the ITER divertor due to its favourable thermal properties, low erosion and fuel retention. Bombardment of tungsten by low energy ions of hydrogen isotopes, at different surface temperature, can lead to surface modifications and influence the fuel accumulation in the material. This contribution will assess the impact of material microstructure and the correlation between the particle flux, surface modifications and deuterium retention in tungsten. Tungsten samples were exposed to deuterium plasma at a surface temperature of 510 K, 670 K and 870 K, ion energy of 40 eV and ion fluence of 10{sup 26} m{sup -2}. The high and low ion flux ranges were in the order 10{sup 24} m{sup -2}s{sup -1} and 10{sup 22} m{sup -2}s{sup -1}. Depth profiling of deuterium in all the samples was done by secondary ion mass spectroscopy technique and a scanning electron microscope was used to investigate the surface modifications. Modelling of the D desorption spectra with the coupled reaction diffusion system model will be also presented.

Isotopic exchange between deuterium and neohexane on supported platinum and palladium catalysts

International Nuclear Information System (INIS)

Eskinazi, V.

1979-01-01

The isotopic exchange reaction between neohexane and deuterium on supported Pt/SiO 2 and Pd/SiO 2 catalysts has been investigated in the temperature range 86.5 to 110 0 C. Rates of exchange were studied as functions of percentage of metal atoms exposed, the conditions of catalyst pretreatment, and the reaction temperature. The rates of exchange were not strongly dependent upon percentage exposed; however, the relative yields of d 1 through d 5 in the ethyl moiety or neohexane were dependent on the percentage metal atoms exposed. The Pt/SiO 2 catalysts were found to be more active for exchange than the Pd/SiO 2 catalysts by an order of magnitude. Both the turnover frequencies and the exchange pattern were observed to be influenced by the pretreatment of the catalyst. Maxima in the exchange pattern occurred at d 3 and d 5 in the case of Pt/SiO 2 and at d 5 only in the case of the Pd/SiO 2 catalysts. In order to account for the d 3 maximum observed for Pt catalysts, some extension of the Horiuti-Polanyi mechanism is required. Mechanisms by which the d 3 species might be formed are proposed and discussed. On Pd/SiO 2 catalysts exchange occurs preferentially in the ethyl substituent of the quaternary carbon atom rather than on the three methyl substituents of the quaternary carbon atom. Such preference is not observed on Pt/SiO 2 catalysts; in fact, in some cases, this preference is reversed. Whenever exchange occurs in the three methyl substituents, mostly the d 1 product is obtained. For Pt/SiO 2 catalysts, the exchange pattern appears to be influenced by steric effects, but the data suggest that factors other than steric effects are important on Pd

Deuterium isotope effects during formation of phenols by hepatic monoxygenases. Evidence for an alternative to the arene oxide pathway

International Nuclear Information System (INIS)

Tomaszewski, J.E.; Jerina, D.M.; Daly, J.W.

1975-01-01

The in vivo and in vitro metabolisms of normal and deuterated aromatic substrates have been investigated in rats. Significant isotope effects (k/ sub H//k/sub D/ equals 1.3-1.75) were associated with in vivo formation of meta-hydroxylated metabolites from 1:1 mixtures of normal and perdeuterio-(arylring) nitrobenzene, methyl phenyl sulfide, and methyl phenyl sulfone. Since isotope effects of this magnitude are incompatible with arene oxides as intermediates in the formation of phenols, the results provide evidence that multiple pathways are responsible for the formation of phenols in mammals. Significant isotope effects were not associated with the formation of the other phenolic isomers of nitrobenzene, methyl phenyl sulfone, or methyl phenyl sulfide or with the formation of phenolic products from anisole, bromobenzene, chlorobenzene, fluorobenzene, benzonitrile, naphthalene, zoxazolamine, acetanilide, biphenyl, diphenylhydantoin, benzene, o- and p-xylene, toluene, and mesitylene. Significant isotope effects might not be observable with the latter substrates if the kinetic parameters for oxidation of substrate change or if the arene oxide pathway greatly predominates. Furthermore, extensive in vivo metabolism of any substrate would make isotope effects unobservable by the procedure employed, namely the analysis of isotope content in metabolites formed from 1:1 mixtures of normal and deuterated substrates. (U.S.)

Synthesis of deuterium-labelled compounds for FOTEK project; Syntese af deuterium-maerkede forbindelser til FOeTEK projektet

Energy Technology Data Exchange (ETDEWEB)

Joergensen, O.; Egsgaard, H.; Larsen, E. [Forskningscenter Risoe, Roskilde (Denmark)

1996-06-01

In the FoTech project there have been utilized labelled compounds of stable isotopes as internal standards. Some of these compounds are commercially available ({sup 13}C-labelled PCB congeners, {sup 13}C-labelled diethylstilbestrol for determination of anabolic steroids). Others, like D{sub 9}-clenbuterol, D{sub 3}-clenbuterol, D{sub 3}-zeramol and D{sub 3}-dimetridazol have been synthesized. General aspects of deuterium compounds labelling are considered. (EG).

Dual Studies on a Hydrogen-Deuterium Exchange of Resorcinol and the Subsequent Kinetic Isotope Effect

Science.gov (United States)

Giles, Richard; Kim, Iris; Chao, Weyjuin Eric; Moore, Jennifer; Jung, Kyung Woon

2014-01-01

An efficient laboratory experiment has been developed for undergraduate students to conduct hydrogen-deuterium (H-D) exchange of resorcinol by electrophilic aromatic substitution using D[subscript 2]O and a catalytic amount of H[subscript 2]SO[subscript 4]. The resulting labeled product is characterized by [superscript 1]H NMR. Students also…

Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

International Nuclear Information System (INIS)

Shimada, Masashi; Hara, Masanori; Otsuka, Teppei; Oya, Yasuhisa; Hatano, Yuji

2015-01-01

Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 10 26 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

Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

Science.gov (United States)

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.

Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

Energy Technology Data Exchange (ETDEWEB)

Shimada, Masashi, E-mail: Masashi.Shimada@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID (United States); Hara, Masanori [Hydrogen Isotope Research Center, University of Toyama, Toyama (Japan); Otsuka, Teppei [Kyushu University, Interdisciplinary Graduate School of Engineering Science, Higashi-ku, Fukuoka (Japan); Oya, Yasuhisa [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan); Hatano, Yuji [Hydrogen Isotope Research Center, University of Toyama, Toyama (Japan)

2015-08-15

Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 10{sup 26} m{sup −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{sup −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.

Use of Fourier transformed infrared spectrophotometer (FTIR) for determination of breastmilk output by the deuterium dilution method among Senegalese women

International Nuclear Information System (INIS)

Sarr Cisse, Aita; Diaham, Babou; Dossou, Nicole; Guiro, Amadou Tidiane; Wade, Salimata; Bluck, Leslie

2002-01-01

Breastmilk output can be estimated from the mother's total body water and water turnover rates after oral administration of deuterium oxide. Usually the deuterium enrichments are determined using a isotope ratio mass spectrometer, which is expensive and requires a specialist for operation and maintenance. Such equipment is dfficult to set up in developing countries. A less expensive method was developed which uses a Fourier transform infrared spectrophotometer (FTIR) for deuterium enrichment analysis. This study evaluated the constraints of using FTIR to study lactating women in Senegal. The deuterium isotope method was found to be adequate for free living subjects and presented few constraints except for the duration of the saliva sampling (14 days). The method offers the opportunity to determine simultaneously breastmilk output, mother's body composition, and breastfeeding practices. Deuterium sample enrichments measured with FTIR were fast and easy, but for spectrum quality some environmental control is required to optimize the results. (Authors)

Producing deuterium-enriched products

International Nuclear Information System (INIS)

1980-01-01

A method of producing an enriched deuterium product from a gaseous feed stream of mixed hydrogen and deuterium, comprises: (a) combining the feed stream with gaseous bromine to form a mixture of the feed stream and bromine and exposing the mixture to an electrical discharge effective to form deuterium bromide and hydrogen bromide with a ratio of D/H greater than the ratio of D/H in the feed stream; and (b) separating at least a portion of the hydrogen bromide and deuterium bromide from the mixture. (author)

Study of isotope effects in the hydrogen transport of an 8% CrWVTa martensitic steel

International Nuclear Information System (INIS)

Esteban, G.A.; Sedano, L.A.; Perujo, A.; Douglas, K.

2001-01-01

A time-dependent gas-phase isovolumetric desorption technique has been used to assess the isotope effects in the diffusive transport parameters of hydrogen in an 8% CrWVTa reduced activation martensitic steel in the temperature range of 423-892 K and driving pressures from 4 x 10 4 - 1 x 10 5 Pa. The experiments have been run with both protium and deuterium obtaining their respective transport parameters, diffusivity (D), Sieverts' constant (K S ), permeability (Φ), trap site density (η t ) and the trapping activation energy (E t ). Isotope effects on steel are analysed and compared with α-iron. A new way to derive more accurate tritium transport parameters is proposed. (orig.)

Kinetic formulae for muon-catalyzed fusion of hydrogen isotopes and their application to the description of the data for pure deuterium

International Nuclear Information System (INIS)

Gula, A.

1987-01-01

The data on the time distributions of muon-catalyzed fusion (μCF) events in pure deuterium targets published before 1987 are analysed using the kinetic formalism developed by the author and collaborators in a series of papers. The formalism enables one to describe these time distributions in an arbitrary mixture of hydrogen isotopes with strict inclusion of registration efficiency and dead time. The kinetic formulae for such distributions can be readily obtained using a prescription based on the theory of signal-flow graphs even for very complicated kinetic situations, thus, allowing one to avoid the simplifying assumptions which have been usually made in earlier analyses. Practically all important processes forming the muon-catalysis chain can be strictly taken into account in the approximation of constant transition rates. Consecutive μCF cycles can be described separately, which provides a useful tool in data analysis. The developed formalism is applied to the existing data for pure deuterium. First cycle-by-cycle time distributions reported for room temperature by the Gatchina group are analysed. 93 refs., 14 figs. (author)

Retention and features of deuterium detrapping from radiation-induced damages in steels

International Nuclear Information System (INIS)

Tolstolutskaya, G.D.; Ruzhytskiy, V.V.; Karpov, S.A.; Kopanets, I.E.

2009-01-01

The accelerators and ion-beam analysis techniques are used for simulation of displacement damage and detailed investigation of distribution profiles of damage and impurity gas atoms (especially helium and hydrogen) in the irradiation of targets for a wide ranges of doses and particle energies. The influence of preimplanted helium and heavy ion-induced damage on deuterium trapping in austenitic and ferritic/martensitic steels was studied. The results obtained for 18Cr10NiTi stainless steel show that ion-implanted deuterium is weakly trapped by defects produced in 5 keV D + displacement cascades. The effective trapping temperature interval is between 300 and 600 K. The characteristics of trapping and the temperature range of hydrogen isotopes retention in traps formed by prior implantation of helium depend on the concentration of implanted helium and on the type of defects developed. The formation of helium bubbles in 18Cr10NiTi steel causes an order of magnitude increase in the content of retained deuterium atoms in the range of temperature 300-600 K and extends the interval of effective trapping temperatures to 1000 K. Energetic heavy-ion irradiation (1.4 MeV Ar + ) has been used for modeling defect cluster formation under displacement cascade conditions to simulate fusion reactor environments. It was found that retention of hydrogen and deuterium strongly increased in this case. It is shown that the presence of a surface-passive film considerably shifts the gas release interval to higher temperatures and reduces the deuterium surface recombination coefficient by several orders of magnitude.

Synthesis of deuterium labelled ibuprofen

International Nuclear Information System (INIS)

Cappon, V.J.; Halstead, G.W.; Theis, D.L.

1986-01-01

The preparations of [ar- 2 H 4 ]-ibuprofen and [ar, 3,3,3- 2 H 7 ]-ibuprofen are described. The deuterium was incorporated into the aromatic ring of [ar- 2 H 4 ]-ibuprofen which is a metabolically stable position. [ar, 3,3,3- 2 H 7 ]-ibuprofen was synthesized by the same route using [ 2 H 3 ]-CH 3 I instead of CH 3 I for use as a GC/MS internal standard in stable isotope labelled bioavailability studies. (author)

Isotope effect study of κ-(BEDT-TTF)2Cu(NCS)2: Labeling in the anion

International Nuclear Information System (INIS)

Kini, A.M.; Wang, H.H.; Schlueter, J.A.

1995-01-01

Since the initial discovery of organic superconductivity in 1979, a large number of organic superconductors have now been synthesized. However, the mechanism of electron-pairing in these novel superconductors has remained largely unresolved. Isotope effect studies constitute an important experimental tool for the investigation of whether or not the electron-pairing mechanism in organic superconductors is phonon-mediated, as in conventional superconductors. Recent isotope effect studies in the authors' laboratory, involving seven different isotopically labeled BEDT-TTF (or ET) derivatives, have demonstrated the following: (1) intramolecular phonon modes involving C double-bond C and Csingle bondS stretching vibrations in the ET donor molecule are not the dominant mediators of electron-pairing, and (2) in κ-(ET) 2 Cu(NCS) 2 , there exist two competing isotope effects--a normal mass effect, i.e., lowering of T c upon isotopic labeling, when the ET molecular mass is increased by concurrent 13 C and 34 S labeling, in addition to an inverse isotope effect upon deuterium labeling in ET. It is of great interest to investigate if there is an isotope effect when the charge-compensating anions, which are also located within the non-conducting layer in the superconducting cation-radical salts, are isotopically labeled. The existence of an isotope effect when the anions are labeled would be indicative of electron-pairing with the mediation of vibrational frequencies associated with the anions. In this paper, the authors present the results of the first isotope effect study in which isotopic labeling in the anion portion of κ-(ET) 2 Cu(NCS) 2 is carried out. The authors find no isotope effect when the carbon and nitrogen atoms of the thiocyanate groups in the anion are replaced with 13 C and 15 N isotopes

Laser separation of hydrogen isotopes: Tritium-from-deuterium recovery

International Nuclear Information System (INIS)

Magnotta, F.; Herman, I.P.; Aldridge, F.T.; Maienschein, J.L.

1984-01-01

Single-step enrichment factors exceeding 15,000 have been observed in the removal of tritium-from-deuterium by 12 μm laser multiple-photon dissociation of chloroform. The photochemistry and photophysics of this process is discussed along with prospects for implementation of this method in practical heavy water reactor detritiation. 7 refs., 7 figs., 1 tab

Effect of helium irradiation on deuterium permeation behavior in tungsten

Energy Technology Data Exchange (ETDEWEB)

Uemura, Yuki; Sakurada, Shodai; Fujita, Hiroe; Azuma, Keisuke; Zhou, Quilai [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan); Hatano, Yuji [Hydrogen Isotope Research Center, University of Toyama, 3190 Gofuku, Toyama, 930-8555 Japan (Japan); Yoshida, Naoaki; Watanabe, Hideo [Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka, 816-8580 Japan (Japan); Oyaizu, Makoto; Isobe, Kanetsugu [National Institutes for Quantum and Radiological Science and Technology, 2166 Obuchi, Rokkasho, Aomori, 039-3212 Japan (Japan); Shimada, Masashi [Idaho National Laboratory, 1955 N. Fremont Avenue, Idaho Falls, ID 83415 (United States); Buchenauer, Dean; Kolasinski, Robert [Sandia National Laboratories, Chemistry, Combustion and Materials Center, Livermore, CA 94550 (United States); Chikada, Takumi [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan); Oya, Yasuhisa, E-mail: oya.yasuhisa@shizuoka.ac.jp [Graduate School of Science & Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529 Japan (Japan)

2017-07-15

In this study, we measured deuterium (D) gas-driven permeation through tungsten (W) foils that had been pre-damaged by helium ions (He{sup +}). The goal of this work was to determine how ion-induced damage affects hydrogen isotope permeation. At 873 K, the D permeability for W irradiated by 3.0 keV He{sup +} was approximately one order of magnitude lower than that for un-damaged W. This difference diminished with increasing temperature. Even after heating to 1173 K, the permeability returned to less than half of the value measured for un-damaged W. We propose that this is due to nucleation of He bubbles near the surface which potentially serve as a barrier to diffusion deeper into the bulk. Exposure at higher temperatures shows that the D permeability and diffusion coefficients return to levels observed for undamaged material. It is possible that these effects are linked to annealing of defects introduced by ion damage, and whether the defects are stabilized by the presence of trapped He.

Analysis of hydrogen-deuterium mixtures and of mixtures of heavy-water and light-water by means of a mass spectrometer

International Nuclear Information System (INIS)

Chenouard, J.; Gueron, J.; Roth, E.

1951-07-01

The differences between hydrogen and deuterium with respect to the capture of thermal neutrons (hydrogen = 0.31 barn; deuterium 0.00065 barn) explains the interest of detecting small variations of the isotopic composition of the heavy waters used in the Chatillon nuclear pile. The aim of this report is to describe and discuss the method used since more than a year for the dosimetry of heavy waters. After a recall of the principle of mass spectroscopy analysis of deuterium-hydrogen mixtures, the preciseness of the results is presented and the balancing method used for the determination of the isotopic composition of hydrogen-deuterium mixtures is explained in detail. Finally, a brief comparison of the preciseness of mass spectroscopy measurements with the analyses made with other methods is performed. Some calculations and the tables of results are presented in appendixes. (J.S.)

Hydrogen-deuterium exchange in imidazole as a tool for studying histidine phosphorylation.

Science.gov (United States)

Cebo, Małgorzata; Kielmas, Martyna; Adamczyk, Justyna; Cebrat, Marek; Szewczuk, Zbigniew; Stefanowicz, Piotr

2014-12-01

Isotope exchange at the histidine C2 atom of imidazole in D2O solution is well known to occur at a significantly slower rate than the exchange of amide protons. Analysis of the kinetics of this isotope-exchange reaction is proposed herein as a method of detecting histidine phosphorylation. This modification of His-containing peptides is challenging to pinpoint because of its instability under acidic conditions as well as during CID-MS analysis. In this work, we investigated the effect of phosphorylation of the histidine side chain in peptides on deuterium-hydrogen exchange (DHX) in the imidazole. The results demonstrate that phosphorylation dramatically slows the rate of the DHX reaction. This phenomenon can be applied to detect phosphorylation of peptides at the histidine residue (e.g., in enzymatic digests). We also found that the influence of the peptide sequence on the exchange kinetics is relatively small. A CID fragmentation experiment revealed that there was no detectable hydrogen scrambling in peptides deuterated at C2 of the imidazole ring. Therefore, MS/MS can be used to directly identify the locations of deuterium ions incorporated into peptides containing multiple histidine moieties.

Isotope effects in the non enzymic glycation of hemoglobin catalyzed by DPG

Energy Technology Data Exchange (ETDEWEB)

Gil, Herminia; Uzcategui, Jorge [Universidad de Los Andes, Merida (Venezuela). Dept. de Quimica

1993-12-31

The paradigmatic reaction of glucose with hemoglobin (Hb A{sub o}) has been studied and is known to occur most rapidly at the N-terminal valine of the {beta}-subunit. An initial, rapid imine formation is succeeded by slower Amadori rearrangement. Non enzymic glycation of Hb A{sub o} was studied in vitro in buffer Tris 10 mM in H{sub 2} O and D{sub 2} O, pH 7.3, pD 7.8 at 37 deg C at a fixed concentration of 2,3 diphosphoglycerate (DPG). The reaction exhibits identical rates in protium and deuterium oxides. When D-glucose-2-h is compared with D-glucose-2-d, the kinetic isotope effect for the DPG-dependent rate is 2.1 {+-} 0.3, while the DPG-independent rate constant shows no isotope effect (1.1 {+-} 0.1). The absence of a rate in isotopic water solvents shows that proton donation for solvent, lyons or DPG does not limit the rate. The substrate isotope effect of around 2 for the DPG kinetic term indicates that the proton abstraction step of the Amadori rearrangement by DPG is wholly or partially rate-limiting for this reaction. (author) 23 refs., 4 figs.

Stable isotope analysis

International Nuclear Information System (INIS)

Tibari, Elghali; Taous, Fouad; Marah, Hamid

2014-01-01

This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

Synthesis of specifically deuterium-labelled pregnanolone and pregnanediol sulphates for metabolic studies in humans.

Science.gov (United States)

Baillie, T A; Sjövall, J; Herz, J E

1975-10-01

A synthesis is reported of 3beta-hydroxy-5alpha-pregnan-20-one sulphate and the disulphate and 3-monosulphate of 5alpha-pregnane-3beta,20alpha-diol, labelled specifically with deuterium in high isotopic purity for metabolic studies in humans. Base-catalyzed equilibration of 3beta-hydroxy-5alpha-25R-spirostan-12-one (hemcogenin, II) with deuterium oxide, followed by removal of the 12-keto group and degradation of the sapogenin side-chain afforded 3beta-hydroxy-5alpha-[11,11-2H2]pregn-16-en-20-one (VII). Further deuterium atoms were introduced at the 3alpha and 20beta positions by reductions with sodium borodeuteride and lithium aluminum deuteride, respectively. These reactions led to 3beta-hydroxy-5alpha-[3alpha,11,11-2H3]pregnan-20-one (X; isotopic purity 87.2%) and 5alpha-[3alpha,11,11,20beta-2H4]pregnane-3beta,20alpha-diol (XIV; isotopic purity 83.9%). The 3-sulphate of the pregnanolone and the 3,20-disulphate of the pregnanediol were prepared directly form the free alcohols, while the 3-monosulphate of the pregnanediol was obtained via 5alpha-[3alpha,11,11,20beta-2H4]pregnane-3beta,20alpha-diol 20-acetate (XVII).

Isotopes in heterogeneous catalysis

CERN Document Server

Hargreaves, Justin SJ

2006-01-01

The purpose of this book is to review the current, state-of-the-art application of isotopic methods to the field of heterogeneous catalysis. Isotopic studies are arguably the ultimate technique in in situ methods for heterogeneous catalysis. In this review volume, chapters have been contributed by experts in the field and the coverage includes both the application of specific isotopes - Deuterium, Tritium, Carbon-14, Sulfur-35 and Oxygen-18 - as well as isotopic techniques - determination of surface mobility, steady state transient isotope kinetic analysis, and positron emission profiling.

Effects of hydrogen mixture into helium gas on deuterium removal from lithium titanate

Energy Technology Data Exchange (ETDEWEB)

Tsuchiya, Akihito, E-mail: tsuchiya@frontier.hokudai.ac.jp [Laboratory of Plasma Physics and Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628 (Japan); Hino, Tomoaki; Yamauchi, Yuji; Nobuta, Yuji [Laboratory of Plasma Physics and Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628 (Japan); Akiba, Masato; Enoeda, Mikio [Japan Atomic Energy Agency, 801-1, Mukoyama, Naka 311-0193 (Japan)

2013-10-15

Lithium titanate (Li{sub 2}TiO{sub 3}) pebbles were irradiated with deuterium ions with energy of 1.7 keV and then exposed to helium or helium–hydrogen mixed gas at various temperatures, in order to evaluate the effects of gas exposure on deuterium removal from the pebbles. The amounts of residual deuterium in the pebbles were measured by thermal desorption spectroscopy. The mixing of hydrogen gas into helium gas enhanced the removal amount of deuterium. In other words, the amount of residual deuterium after the helium–hydrogen mixed gas exposure at lower temperature was lower than that after the helium gas exposure. In addition, we also evaluated the pebbles exposed to the helium gas with different hydrogen mixture ratio from 0% to 1%, at 573 K. Although the amount of residual deuterium in the pebbles after the exposure decreased with increasing the hydrogen mixture ratio, the implanted deuterium partly remained after the exposure. These results suggest that the tritium inventory may occur at low temperature region in the blanket during the operation.

Deuterium dilution technique for body composition assessment: resolving methodological issues in children with moderate acute malnutrition.

Science.gov (United States)

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.

Primary and secondary kinetic isotope effects in the acid-catalyzed dehydration of 1,1'-diadamantylmethylcarbinol in aqueous acetic acid

International Nuclear Information System (INIS)

Lomas, J.S.

1981-01-01

The sulfuric acid catalyzed dehydration of 1,1'-diadamantyl-methylcarbinol in anhydrous acetic acid proceeds exclusively to 1,1'-bis(1-adamantyl)ethylene. The secondary deuterium isotope effect of 1.32 found for this reaction shows that carbonium ion formation from the protonated alcohol is rate determining. In the presence of water, however, capture of the carbonium ion competes with deprotonation, introducing a primary isotope effect. Consequently, the overall KIE rises, reaching 3.18 for 80% aqueous acetic acid. Analysis of the KIE for 80 to 100% aqueous acetic acid is consistent with a simple classical mechanism involving reversible formation of the intermediate carbonium ion. The primary isotope effect upon deprotonation is at the most 2.98, indicative of an asymmetric transition state close to the carbonium ion

Isotopic research in Antarctica

International Nuclear Information System (INIS)

Schuetze, H.

1983-01-01

Since 1978 scientists of the Central Institute of Isotope- and Radiation Research of the Academy of Sciences of the GDR have participated in antarctic research. Substantial results have been achieved in research on isotope ratios, on the dynamics of water resources, on concentration of deuterium in lichens, and on age determination of a mummified seal and a penguin colony

Isotope exchange between gaseous hydrogen and uranium hydride powder

International Nuclear Information System (INIS)

Shugard, Andrew D.; Buffleben, George M.; Johnson, Terry A.; Robinson, David B.

2014-01-01

Highlights: • Isotope exchange between hydrogen gas and uranium hydride powder can be rapid and reversible. • Gas–solid exchange rate is controlled by transport within ∼0.7 μm hydride particles. • Gas chromatographic separation of hydrogen isotopes using uranium hydride is feasible. - Abstract: Isotope exchange between gaseous hydrogen and solid uranium hydride has been studied by flowing hydrogen (deuterium) gas through packed powder beds of uranium deuteride (hydride). We used a residual gas analyzer system to perform real-time analysis of the effluent gas composition. We also developed an exchange and transport model and, by fitting it to the experimental data, extracted kinetic parameters for the isotope exchange reaction. Our results suggest that, from approximately 70 to 700 kPa and 25 to 400 °C, the gas-to-solid exchange rate is controlled by hydrogen and deuterium transport within the ∼0.7 μm diameter uranium hydride particles. We use our kinetic parameters to show that gas chromatographic separation of hydrogen and deuterium using uranium hydride could be feasible

Hydrogen--deuterium exchange in saturated hydrocarbons on α-chromia catalyst

International Nuclear Information System (INIS)

Kalman, J.; Guczi, L.

1977-01-01

The kinetics of hydrogen--deuterium exchange in methane, ethane, and propane have been studied with unsupported α-chromia as catalyst in the temperature range of 598 to 688 0 K. The apparent activation energies for methane, ethane, and propane are 88, 130, and 84 kJ mol -1 , respectively, similar to those found on chromia gel. The order of reaction with respect to hydrocarbons and deuterium has been determined as also having the kinetic isotope effect. The main initial products are CH 3 D and CD 4 with methane, C 2 H 4 D 2 and C 2 D 6 with ethane, and C 3 H 7 D and C 3 D 8 with propane. A change in product distribution as a function of temperature, conversion, aging, and oxygen--deuterium treatment has been observed. In agreement with the kinetic data and the effect of oxygen, Cr 3+ has been assumed as the active species of the chromia catalyst, whereas Cr 2+ is an inactive site on the surface. There is no direct proof that chromium ion in a valence state higher than 3+ plays an important role in the exchange reaction. It was established that dual Cr 3+ -- Cr 3+ sites are responsible for the formation of ethane-d 2 . After a long deuterium treatment the number of dual sites is decreased, the effect being revealed in the decreased rate of exchange and the small amount of ethane-d 2 . On the contrary, the formation of methane-d 4 is interpreted by the formation of Cr = C bonds by analogy with homogeneous complexes. In the case of propane, the exchange reaction can be adequately interpreted by a π-allyl mechanism

On line determination of deuterium in hydrogen water exchange reaction by mass spectrometry. IRP-10

International Nuclear Information System (INIS)

Sharma, J.D.; Alphonse, K.P.; Mishra, Sushama; Prabhu, S.A.; Mohan, Sadhana; Tangri, V.K.

2007-01-01

The Deuterium (D)/Hydrogen (H) analysis at low Concentration is generally carried out by Mass Spectrometry. Mass Spectrometer is specially designed for the measurement of Mass 2 and 3 ratio. The Deuterium analysis of water and hydrogen in concentration range of a few ppm to about 1% plays an important role in the Heavy Water Production Plants. For the enrichment of the Deuterium concentration in H 2 O by H 2 - H 2 O exchange a catalyst is essential as reaction is relatively slow. Heavy Water Division has developed in house Platinum based catalyst for the isotopic exchange of Hydrogen and Water

Separation of rate processes for isotopic exchange between hydrogen and liquid water in packed columns 10

International Nuclear Information System (INIS)

Butler, J.P.; Hartog, J. den; Goodale, J.W.; Rolston, J.H.

1977-01-01

Wetproofed platinum catalysts in packed columns promote isotopic exchange between counter-current streams of hydrogen saturated with water vapour and liquid water. The net rate of deuterium transfer from isotopically enriched hydrogen has been measured and separated into two rate processes involving the transfer of deuterium from hydrogen to water vapour and from water vapour to liquid. These are compared with independent measurements of the two rate processes to test the two-step successive exchange model for trickle bed reactors. The separated transfer rates are independent of bed height and characterize the deuterium concentrations of each stream along the length of the bed. The dependences of the transfer rates upon hydrogen and liquid flow, hydrogen pressure, platinum loading and the effect of dilution of the hydrophobic catalyst with inert hydrophilic packing are reported. The results indicate a third process may be important in the transfer of deuterium between hydrogen and liquid water. (author)

Hydrocarbon isotope detection by elastic peak electron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Kostanovskiy, I.A., E-mail: kostanovskiyia@gmail.com [National Research University MPEI, Krasnokazarmennaya 14, 111250 Moscow (Russian Federation); Afanas’ev, V.P. [National Research University MPEI, Krasnokazarmennaya 14, 111250 Moscow (Russian Federation); Naujoks, D. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstraße 1, D-17491 Greifswald (Germany); Mayer, M. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany)

2015-07-15

Highlights: • PCVD hydrocarbon coatings containing protium or deuterium are analyzed via NRA, ERD, XPS and EPES. • EPES analysis with modern electron energy analyzer SPECS Phoibos 225 shows a clear signal from the hydrogen isotopes. • Different primary energies and scattering angles help to quantify isotope content from EPES spectra. - Abstract: Experimental results on the hydrocarbon isotope analysis by elastic peak electron spectroscopy are presented. Amorphous hydrocarbon samples (a-C:H, a-C:D) are prepared by PCVD and analyzed by nuclear reaction analysis (NRA), elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES). Electron energy spectra show a clear signal from the hydrogen isotopes deuterium and protium. Different incident energies and scattering geometries help to resolve plasmon and elastic energy losses.

Hydrocarbon isotope detection by elastic peak electron spectroscopy

International Nuclear Information System (INIS)

Kostanovskiy, I.A.; Afanas’ev, V.P.; Naujoks, D.; Mayer, M.

2015-01-01

Highlights: • PCVD hydrocarbon coatings containing protium or deuterium are analyzed via NRA, ERD, XPS and EPES. • EPES analysis with modern electron energy analyzer SPECS Phoibos 225 shows a clear signal from the hydrogen isotopes. • Different primary energies and scattering angles help to quantify isotope content from EPES spectra. - Abstract: Experimental results on the hydrocarbon isotope analysis by elastic peak electron spectroscopy are presented. Amorphous hydrocarbon samples (a-C:H, a-C:D) are prepared by PCVD and analyzed by nuclear reaction analysis (NRA), elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES). Electron energy spectra show a clear signal from the hydrogen isotopes deuterium and protium. Different incident energies and scattering geometries help to resolve plasmon and elastic energy losses

Impurity effects of hydrogen isotope retention on boronized wall in LHD

International Nuclear Information System (INIS)

Oya, Yasuhisa; Okuno, Kenji; Ashikawa, Naoko; Nishimura, Kiyohiko; Sagara, Akio

2010-11-01

The impurity effect on hydrogen isotopes retention in the boron film deposited in LHD was evaluated by means of XPS and TDS. It was found that the impurity concentrations in boron film were increased after H-H main plasma exposure in LHD. The ratio of hydrogen retention trapped by impurity to total hydrogen retention during H-H main plasma exposure was reached to 70%, although that of deuterium retention by impurity in D 2 + implanted LHD-boron film was about 35%. In addition, the dynamic chemical sputtering of hydrogen isotopes with impurity as the form of water and / or hydrocarbons was occurred by energetic hydrogen isotopes irradiation. It was expected that the enhancement of impurity concentration during plasma exposure in LHD would induce the dynamic formation of volatile molecules and their re-emission to plasma. These facts would prevent stable plasma operation in LHD, concluding that the dynamic impurity behavior in boron film during plasma exposure is one of key issues for the steady-state plasma operation in LHD. (author)

Synthesis of deuterium-labelled compounds for FOTEK project

International Nuclear Information System (INIS)

Joergensen, O.; Egsgaard, H.; Larsen, E.

1996-01-01

In the FoTech project there have been utilized labelled compounds of stable isotopes as internal standards. Some of these compounds are commercially available ( 13 C-labelled PCB congeners, 13 C-labelled diethylstilbestrol for determination of anabolic steroids). Others, like D 9 -clenbuterol, D 3 -clenbuterol, D 3 -zeramol and D 3 -dimetridazol have been synthesized. General aspects of deuterium compounds labelling are considered. (EG)

Synthesis of deuterium and tritium labelled tyrosine

International Nuclear Information System (INIS)

Kanska, M.; Drabarek, S.

1980-01-01

A new method of synthesis of tyrosine labelled with deuterium and tritium in the aromatic ring has been developed. Deuterated and tritiated tyrosine was obtained by isotope exchange between tyrosine and deuterated or tritiated water at elevated temperature in hydrochloric acid medium using K 2 PtCl 4 as a catalyst. For synthesis of tritiated tyrosine 1 Ci HTO was used; the specific activity of the product was 5 mCi/mMol. (author)

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

Energy Technology Data Exchange (ETDEWEB)

Kuehnel, Matthias

2014-02-15

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

International Nuclear Information System (INIS)

Kuehnel, Matthias

2014-02-01

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

Energy Technology Data Exchange (ETDEWEB)

Kuehnel, Matthias

2014-02-15

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Stable isotopic composition of East African lake waters

International Nuclear Information System (INIS)

Odada, E.O.

2001-01-01

The investigation of stable isotopic composition of East African lake waters was conducted by scientists from the Department of Geology, University of Nairobi, as part of the International Decade for the East African Lakes (IDEAL) project and in close collaboration with the scientists from Large Lakes Observatory of the University of Minnesota and the Isotope Hydrology Laboratory of the IAEA in Vienna. The Research Contract was part of the IAEA Co-ordinated Research Programme on Isotope Techniques in Lake Dynamics Investigations, and was sponsored by the Agency. Water and grab sediment samples were obtained from East African Lakes during the month of January and February 1994 and July/August 1995. Water samples were analysed for oxygen and deuterium isotopic composition at the IAEA Laboratories in Vienna, Austria. In this final paper we report the results of the study of oxygen and deuterium isotopic composition from the East African lake waters. (author)

Process chemistry related to hydrogen isotopes

International Nuclear Information System (INIS)

Iwasaki, Matae; Ogata, Yukio

1991-01-01

Hydrogen isotopes, that is, protium, deuterium and tritium, are all related deeply to energy in engineering region. Deuterium and tritium exist usually as water in extremely thin state. Accordingly, the improvement of the technology for separating these isotopes is a large engineering subject. Further, tritium is radioactive and its half-life period is 12.26 years, therefore, it is desirable to fix it in more stable form besides its confinement in the handling system. As the chemical forms of hydrogen, the molecular hydrogen with highest reactivity, metal hydride, carbon-hydrogen-halogen system compounds, various inorganic hydrides, most stable water and hydroxides are enumerated. The grasping of the behavior from reaction to stable state of these hydrogen compounds and the related materials is the base of process chemistry. The reaction of exchanging isotopes between water and hydrogen on solid catalyzers, the decomposition of ethane halide containing hydrogen, the behavior of water and hydroxides in silicates are reported. The isotope exchange between water and hydrogen is expected to be developed as the process of separating and concentrating hydrogen isotopes. (K.I.) 103 refs

Radiation damage and deuterium trapping in deuterium-ion-irradiated Fe–9Cr alloy

Energy Technology Data Exchange (ETDEWEB)

Iwakir, Hirotomo, E-mail: iwakiri@edu.u-ryukyu.ac.jp [Faculty and Graduate School of Education, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan); Tani, Munechika [Interdisciplinary Graduate School of Engineering Sciences, Kyusyu University, Kasuga, Fukuoka 816-8580 (Japan); Watanabe, Yoshiyuki [Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Yoshida, Naoaki [Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan)

2014-01-15

Thermal desorption of deuterium (D{sub 2}) from deuterium-ion (D{sub 2}{sup +})-irradiated Fe–9Cr was correlated with the microstructural evolution of the alloy during irradiation with 8-keV D{sub 2}{sup +} ions following annealing to determine the retention and desorption behavior of the implanted deuterium and to identify effective traps for them, particularly at high temperature. After irradiation at 573 K, a new desorption stage formed between 650 and 1100 K at higher fluences, and cavities were observed using transmission electron microscopy. The total amount of trapped deuterium following irradiation with a fluence of 3.0 × 10{sup 22} ions/m{sup 2} was 6.8 × 10{sup 17} D{sub 2}/m{sup 2}, or approximately 0.007%. These results indicate that the deuterium atoms recombined to form D{sub 2} molecules at the surfaces of the cavities.

Isotope exchange reaction on solid breeder materials

International Nuclear Information System (INIS)

Baba, A.; Nishikawa, M.; Eguchi, T.; Kawagoe, T.

2000-01-01

Lithium ceramic materials such as Li 2 O, LiAlO 2 , Li 2 ZrO 3 , Li 2 TiO 3 and Li 4 SiO 4 are considered to be as candidate for the tritium breeding material in a deuterium-tritium (D-T) fusion reactor. In the recent blanket designs, helium gas with hydrogen or deuterium is planned to be used as the blanket purge gas to reduce tritium inventory and promote tritium release from the breeding material. In addition, the rate of isotope exchange reaction between hydrogen isotopes in the purge gas and tritium on the surface of the breeding material is necessary to analyze the tritium release behavior from the breeding materials. However, the rate of isotope exchange reactions between hydrogen isotopes in the purge gas and tritium on the surface of those materials has not been quantified until recently. Recently, the present authors quantified the rate of isotope exchange reaction on Li 2 O and Li 2 ZrO 3 . The overall mass transfer coefficients representing the isotope exchange reaction between H 2 and D 2 O on breeding materials or the same between D 2 and H 2 O are experimentally obtained in this study. Comparison to isotope exchange reaction rates on various breeding materials is also performed in this study. Discussions about the effects of temperature, concentration of hydrogen in the purge gas or flow rate of the purge gas on the conversion of tritiated water to tritium gas are also performed

Absolute determination of the deuterium content of heavy water, measurement of absolute density

International Nuclear Information System (INIS)

Ceccaldi, M.; Riedinger, M.; Menache, M.

1975-01-01

The absolute density of two heavy water samples rich in deuterium (with a grade higher than 99.9%) was determined with the hydrostatic method. The exact isotopic composition of this water (hydrogen and oxygen isotopes) was very carefully studied. A theoretical estimate enabled us to get the absolute density value of isotopically pure D 2 16 O. This value was found to be 1104.750 kg.m -3 at t 68 =22.3 0 C and under the pressure of one atmosphere. (orig.) [de

Regional and temporal variations of deuterium in the precipitation and atmospheric moisture of Central Europe

International Nuclear Information System (INIS)

Huebner, H.; Kowski, P.; Hermichen, W.D.; Richter, W.; Schuetze, H.

1979-01-01

Regional and temporal variations of deuterium in precipitation and in atmospheric moisture provide the opportunity to balance water cycles as additional but independent information. Variations of deuterium have been measured in precipitation samples from six stations in different zones of the German Democratic Republic since 1972. The aim of the subsequent mathematical processing was to find a functional connection between the deuterium variations and the meteorological parameters causing them. The isotopic content of atmospheric moisture in different air masses and the isotopic content of precipitation are determined by the evaporation conditions of the area of origin and by the number and intensity of evaporation and condensation (precipitation) processes en route from this area of origin to the observation point. Obviously the temperatures at which evaporation and condensation processes take place are of crucial importance. The deuterium values are correlated with the monthly mean temperature. It has been observed, for example, that the equations of regression between precipitation and atmospheric moisture (valid in the case of Leipzig station) differ only with regard to their absolute terms. This follows from the fact that the deuterium is generally enriched by up to 80 per mille in precipitation. Following the well-known fact that many meteorological phenomena show frequencies, an attempt was made to apply the Fourier analysis for the deltaD variations. Relevant harmonic parts were found in all the deltaD series studied, which are repetitious and independent of the station and the observation period. (author)

Isotopic quantum correction to liquid methanol at -30 C

CERN Document Server

Benmore, C J; Egelstaff, P A; Neuefeind, J

2002-01-01

Hydrogen/deuterium (H/D) substitution of molecular liquids in neutron diffraction is a powerful tool for structure determination. However, recent high-energy X-ray studies have found observable differences in the structures of many H and D liquids at the same temperature. In some cases this isotopic quantum effect can be corrected for by measuring the D sample at a slightly different temperature to the H sample. The example of hydroxyl isotopic substitution in liquid methanol at -30 C is presented. The magnitude of the quantum effect is shown to be significant when compared to the size of the first-order isotopic neutron-difference function. (orig.)

Modelling the Spatial Isotope Variability of Precipitation in Syria

Energy Technology Data Exchange (ETDEWEB)

Kattan, Z.; Kattaa, B. [Department of Geology, Atomic Energy Commission of Syria (AECS), Damascus (Syrian Arab Republic)

2013-07-15

Attempts were made to model the spatial variability of environmental isotope ({sup 18}O, {sup 2}H and {sup 3}H) compositions of precipitation in syria. Rainfall samples periodically collected on a monthly basis from 16 different stations were used for processing and demonstrating the spatial distributions of these isotopes, together with those of deuterium excess (d) values. Mathematically, the modelling process was based on applying simple polynomial models that take into consideration the effects of major geographic factors (Lon.E., Lat.N., and altitude). The modelling results of spatial distribution of stable isotopes ({sup 18}O and {sup 2}H) were generally good, as shown from the high correlation coefficients (R{sup 2} = 0.7-0.8), calculated between the observed and predicted values. In the case of deuterium excess and tritium distributions, the results were most likely approximates (R{sup 2} = 0.5-0.6). Improving the simulation of spatial isotope variability probably requires the incorporation of other local meteorological factors, such as relative air humidity, precipitation amount and vapour pressure, which are supposed to play an important role in such an arid country. (author)

Rapid deuterium exchange-in time for probing conformational change

International Nuclear Information System (INIS)

Dharmasiri, K.; Smith, D.L.

1995-01-01

Isotopic exchange of protein backbone amide hydrogens has been used extensively as a sensitive probe of protein structure. One of the salient features of hydrogen exchange is the vast range of exchange rates in one protein. Isotopic exchange methods have been used to study the structural features including protein folding and unfolding (1), functionally different forms of proteins (2), protein-protein complexation (3), and protein stability parameter. Many backbone amide protons that are surface accessible and are not involved in hydrogen bonding undergo rapid deuterium exchange. In order to study, fast exchanging amide protons, fast exchange-in times are necessary

Reaction rates and electrical resistivities of the hydrogen isotopes with, and their solubilities in, liquid lithium

International Nuclear Information System (INIS)

Pulham, R.J.; Adams, P.F.; Hubberstey, P.; Parry, G.; Thunder, A.E.

1976-01-01

The rate of reaction, k, of hydrogen and of deuterium with liquid lithium have been determined up to pressures of 20kNm -2 and at temperatures between 230 and 270 0 C. The reaction is first order with an apparent activation energy of 52.8 and 55.2 kJmol -1 for hydrogen and deuterium, respectively. The deuterium isotope effect, k/sub H/k/sub D/, decreases from 2.95 at 230 to 2.83 at 270 0 C. Tritium is predicted to react even more slowly than deuterium. The freezing point of lithium is depressed by 0.082 and 0.075 0 C, respectively, by dissolved hydride and deuteride giving eutectics at 0.016 mol percent H and 0.012 mol percent D in the metal-salt phase diagrams. The depression and eutectic concentration are expected to be less for tritium. The increase in the resistivity of liquid lithium caused by dissolved hydrogen isotopes is linear and relatively large, 5 x 10 -8 Ωm (mol percent H or D) -1 . The solubility of lithium hydride and deuteride was determined from the marked change in resistivity on saturation. The liquidus of the metal-salt phase diagram rises steeply from the eutectic point to meet the two-immiscible liquid region. Tritium is expected to be less soluble than deuterium. The partial molar enthalpies of solution are 44.2 and 55.0 kJmol -1 for hydrogen and deuterium, respectively. These values are used to calculate the solvation enthalpies of the isotope anions in the metal

Isotope hydrology. Raigon aquifer hydrochemistry - Uruguay

International Nuclear Information System (INIS)

Plata Bedmar, A.; Dellepere, A.; Roma, M.T; Ramirez, M.; Garat, S.; Padros, D.; Caristo, R.; Lavanca, R.; Aranda, E.; Michelis, G.; Monroi, F.; Luaces, A.

2001-01-01

The purpose of this study is the Raigon Acuifer investigation by isotopic techniques as well as the dynamic behavior in the water resources. These techniques are based on the natural water isotope deuterium, oxygen-18, tritium and carbon-14 measurement. The hydrochemistry is used like a complementary tool

Cytology is advanced by studying effects of deuterium environment

Science.gov (United States)

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.

Measurement and Characterization of Hydrogen-Deuterium Exchange Chemistry Using Relaxation Dispersion NMR Spectroscopy.

Science.gov (United States)

Khirich, Gennady; Holliday, Michael J; Lin, Jasper C; Nandy, Aditya

2018-03-01

One-dimensional heteronuclear relaxation dispersion NMR spectroscopy at 13 C natural abundance successfully characterized the dynamics of the hydrogen-deuterium exchange reaction occurring at the N ε position in l-arginine by monitoring C δ in varying amounts of D 2 O. A small equilibrium isotope effect was observed and quantified, corresponding to ΔG = -0.14 kcal mol -1 . A bimolecular rate constant of k D = 5.1 × 10 9 s -1 M -1 was determined from the pH*-dependence of k ex (where pH* is the direct electrode reading of pH in 10% D 2 O and k ex is the nuclear spin exchange rate constant), consistent with diffusion-controlled kinetics. The measurement of ΔG serves to bridge the millisecond time scale lifetimes of the detectable positively charged arginine species with the nanosecond time scale lifetime of the nonobservable low-populated neutral arginine intermediate species, thus allowing for characterization of the equilibrium lifetimes of the various arginine species in solution as a function of fractional solvent deuterium content. Despite the system being in fast exchange on the chemical shift time scale, the magnitude of the secondary isotope shift due to the exchange reaction at N ε was accurately measured to be 0.12 ppm directly from curve-fitting D 2 O-dependent dispersion data collected at a single static field strength. These results indicate that relaxation dispersion NMR spectroscopy is a robust and general method for studying base-catalyzed hydrogen-deuterium exchange chemistry at equilibrium.

Application of Environmental Isotopes in Hydrological Studies Along the River Nile Valley, Egypt

Energy Technology Data Exchange (ETDEWEB)

Nada, A. A. [Site and Environmental Dept. NCNSRC, Atomic Energy Authority, Cairo (Egypt)

2013-07-15

This paper reviews some of the contributions of isotope techniques to better understanding hydrological problems in Egypt and the Nile basin. The stable isotope composition of precipitation shows considerable variations both in time and space since it is controlled by climatic factors. Surface waters became enriched in deuterium and oxygen-18 relative to their initial isotopic composition as losses by evaporation occur. The GNIP sampling stations at Entebbe and Addis Ababa, which are located at the source of the Nile River, present relatively depleted isotopic contents. Assuming that the central Africa runoff (White Nile downstream from Sudan) represents 30% of the natural discharge of Egypt, and the remaining 70% is derived from Ethiopia (Blue Nile), we obtain a composite depleted stable isotope composition of the river Nile reaching upper Egypt under natural conditions (before the construction of the Aswan High Dam). Stable isotopes were used to estimate the evaporation rate from Lake Nasser, based on the isotopic content of the lake water. The lake can be divided into two sectors: the first sector, with remarkable vertical gradient in O-18 and deuterium, and a second sector, characterized by a lower vertical isotopic gradient. In order to detect this effect, surface Nile water samples have been collected at Cairo after a heavy storm event covering all Egypt at the beginning of November 1994, characterized by very negative deuterium and oxygen-18 contents. The isotopic content of Nile water samples fluctuated and slightly changed with time. The variation of the bomb tritium response of the Nile has been reconstructed using a model based on the contents in the catchment areas of the Nile. Pre-bomb tritium content in the Nile was about 5 TU, reaching a maximum level during the early sixties of about 500 TU. At present the tritium level content of the Nile is about 6 TU. (author)

Mechanistic positron emission tomography studies: demonstration of a deuterium isotope effect in the monoamine oxidase-catalyzed binding of (/sup 11/C)L-deprenyl in living baboon brain

Energy Technology Data Exchange (ETDEWEB)

Fowler, J.S.; Wolf, A.P.; MacGregor, R.R.; Dewey, S.L.; Logan, J.; Schlyer, D.J.; Langstrom, B.

1988-11-01

The application of positron emission tomography (PET) to the study of biochemical transformations in the living human and animal body requires the development of highly selective radiotracers whose concentrations in tissue provide a record of a discrete metabolic process. L-N-(11C-methyl)Deprenyl ((11C)L-deprenyl), a suicide inactivator of monoamine oxidase (MAO) type B, has been developed as a radiotracer for mapping MAO B in the living human and animal brain. In this investigation, (11C)L-deprenyl (1) and (11C)L-deprenyl-alpha, alpha-2H2 (2) have been compared in three different baboons by PET measurement of carbon-11 uptake and retention in the brain and the measurement of the amount of unchanged tracer in the arterial plasma over a 90-min time interval. For one baboon, N-(11C-methyl-2H3)L-deprenyl (3) was also studied. Kinetic parameters calculated using a three-compartment model revealed a deuterium isotope effect of 3.8 +/- 1.1. Comparison of the two tracers (1 and 2) in mouse brain demonstrated that deuterium substitution significantly reduced the amount of radioactivity bound to protein. HPLC and GLC analysis of the soluble radioactivity in mouse brain after injection of (11C)L-deprenyl showed the presence of (11C)methamphetamine as a major product along with unidentified labeled products. Sodium dodecyl sulfate-polyacrylamide electrophoresis with carbon-14-labeled L-deprenyl showed that a protein of molecular weight 58,000 was labeled. These results establish that MAO-catalyzed cleavage of the alpha carbon-hydrogen bond on the propargyl group is the rate limiting (or a major rate contributing) step in the retention of carbon-11 in brain and that the in vivo detection of labeled products in brain after the injection of (11C)L-deprenyl provides a record of MAO activity.

Biotechnological Patents Applications of the Deuterium Oxide in Human Health.

Science.gov (United States)

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.

An isotope dependent study of acetone in its lowest excited triplet state

International Nuclear Information System (INIS)

Gehrtz, M.; Brauchle, C.; Voitlaender, J.

1984-01-01

The lowest excited triplet state T 1 of acetone-h 6 and acetone-d 6 was investigated with a pulsed dye laser equipped ODMR spectrometer. Acetone is found to be bent in T 1 and the out-of-plane distortion angle is estimated to be approx.= 38 0 . The observed zero-field splitting (ZFS) is surprisingly small. Both the spin-spin and the spin-orbit (SO) contribution to the ZFS are evaluated. The SO tensor contribution is calculated from a correlation between the deuterium effects on the ZFS parameters and the population rates. The sub-level selective kinetics of the acetone T 1 is largely determined by the mixing of the x- and z-level characteristics owing to magnetic axis rotation caused by the excited state out-of-plane distortion. Considerable deuterium effects are observed on the kinetic data and on the microwave transition frequencies. In all cases the spin-specific isotope effects (due to the promoting modes) and the global effects (due to the Franck-Condon factors) are specified. For the population rates and the SO contribution to ZFS, the inverse global isotope effects (deuterium factor > 1) was found for the first time. Based on the isotope dependence of the rates, the mechanisms of (vibrationally induced) SO coupling in acetone are discussed. It is concluded that non-adiabatic contributions have to be taken into account for the smallest population rate only, but that otherwise the adiabatic SO coupling mechanisms by far dominates in the acetone photophysics. (author)

Physics of high performance deuterium-tritium plasmas in TFTR

International Nuclear Information System (INIS)

McGuire, K.M.; Batha, S.

1996-11-01

During the past two years, deuterium-tritium (D-T) plasmas in the Tokamak Fusion Test Reactor (TFTR) have been used to study fusion power production, isotope effects associated with tritium fueling, and alpha-particle physics in several operational regimes. The peak fusion power has been increased to 10.7 MW in the supershot mode through the use of increased plasma current and toroidal magnetic field and extensive lithium wall conditioning. The high-internal-inductance (high-I i ) regime in TFTR has been extended in plasma current and has achieved 8.7 MW of fusion power. Studies of the effects of tritium on confinement have now been carried out in ohmic, NBI- and ICRF- heated L-mode and reversed-shear plasmas. In general, there is an enhancement in confinement time in D-T plasmas which is most pronounced in supershot and high-I i discharges, weaker in L-mode plasmas with NBI and ICRF heating and smaller still in ohmic plasmas. In reversed-shear discharges with sufficient deuterium-NBI heating power, internal transport barriers have been observed to form, leading to enhanced confinement. Large decreases in the ion heat conductivity and particle transport are inferred within the transport barrier. It appears that higher heating power is required to trigger the formation of a transport barrier with D-T NBI and the isotope effect on energy confinement is nearly absent in these enhanced reverse-shear plasmas. Many alpha-particle physics issues have been studied in the various operating regimes including confinement of the alpha particles, their redistribution by sawteeth, and their loss due to MHD instabilities with low toroidal mode numbers. In weak-shear plasmas, alpha-particle destabilization of a toroidal Alfven eigenmode has been observed

Dynamic isotope effect on the product energy partitioning in CH2OH+→CHO++H2

Science.gov (United States)

Rhee, Young Min; Kim, Myung Soo

1998-10-01

The deuterium isotope effect on the product energy partitioning in the title reaction was investigated both experimentally and theoretically. The measured kinetic energy release (KER) showed a significant dependence on the position of deuteration. A reliable potential energy surface of the reaction was constructed from ab initio results using the recently developed interpolation algorithm. The classical trajectory calculation on this surface well reproduced the experimental finding. Close inspection of the potential energy surface revealed that the isotope effect on KER and the product rotations arose from the alteration of the symmetry of the reaction path near the transition state induced by the mass change upon isotopic substitution. The product vibrations were found to be affected by the change in the coupling constants which also arose from the mass-dependent change in the reaction path. Possibility of the quantum mechanical tunneling was also considered. Tunneling-corrected classical trajectory results were in excellent agreement with the experimental ones, indicating that the reaction proceeds via barrier penetration below the threshold.

Isotopic Abundance and Chemical Purity Analysis of Stable Isotope Deuterium Labeled Sudan I

Directory of Open Access Journals (Sweden)

CAI Yin-ping;LEI Wen;ZHENG Bo;DU Xiao-ning

2014-02-01

Full Text Available It is important that to analysis of the isotopic abundance and chemical purity of Sudan I-D5, which is the internal standard of isotope dilution mass spectrometry. The isotopic abundance of Sudan I-D5 is detected by “mass cluster” classification method and LC-MS. The repeatability and reproducibility experiments were carried out by using different mass spectrometers and different operators. The RSD was less than 0.1%, so the repeatability and reproducibility were satisfactory. The accuracy and precision of the isotopic abundance analysis method was good with the results of F test and t test. The high performance liquid chromatography (HPLC had been used for detecting the chemical purity of Sudan I-D5 as external standard method.

Cosmic Deuterium and Social Networking Software

Science.gov (United States)

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

Synthesis of deuterium-labeled analogs of the lipid hydroperoxide-derived bifunctional electrophile 4-oxo-2(E)-nonenal.

Science.gov (United States)

Arora, Jasbir S; Oe, Tomoyuki; Blair, Ian A

2011-05-15

Lipid hydroperoxides undergo homolytic decomposition into the bifunctional 4-hydroxy-2( E )-nonenal and 4-oxo-2( E )-nonenal (ONE). These bifunctional electrophiles are highly reactive and can readily modify intracellular molecules including glutathione (GSH), deoxyribonucleic acid (DNA) and proteins. Lipid hydroperoxide-derived bifunctional electrophiles are thought to contribute to the pathogenesis of a number of diseases. ONE is an α , β -unsaturated aldehyde that can react in multiple ways and with glutathione, proteins and DNA. Heavy isotope-labeled analogs of ONE are not readily available for conducting mechanistic studies or for use as internal standards in mass spectrometry (MS)-based assays. An efficient onestep cost-effective method has been developed for the preparation of C-9 deuterium-labeled ONE. In addition, a method for specific deuterium labeling of ONE at C-2, C-3 or both C-2 and C-3 has been developed. This latter method involved the selective reduction of an intermediate alkyne either by lithium aluminum hydride or lithium aluminum deuteride and quenching with water or deuterium oxide. The availability of these heavy isotope analogs will be useful as internal standards for quantitative studies employing MS and for conducting mechanistic studies of complex interactions between ONE and DNA bases as well as between ONE and proximal amino acid residues in peptides and proteins.

Hydrogen isotope effect through Pd in hydrogen transport pipe

International Nuclear Information System (INIS)

Tamaki, Masayoshi

1992-01-01

This investigation concerns hydrogen system with hydrogen transport pipes for transportation, purification, isotope separation and storage of hydrogen and its isotopes. A principle of the hydrogen transport pipe (heat pipe having hydrogen transport function) was proposed. It is comprised of the heat pipe and palladium alloy tubes as inlet, outlet, and the separation membrane of hydrogen. The operation was as follows: (1) gas was introduced into the heat pipe through the membrane in the evaporator; (2) the introduced gas was transported toward the condenser by the vapor flow; (3) the transported gas was swept and compressed to the end of the condenser by the vapor pressure; and (4) the compressed gas was exhausted from the heat pipe through the membrane in the condenser. The characteristics of the hydrogen transport pipe were examined for various working conditions. Basic performance concerning transportation, evacuation and compression was experimentally verified. Isotopic dihydrogen gases (H 2 and D 2 ) were used as feed gas for examining the intrinsic performance of the isotope separation by the hydrogen transport pipe. A simulated experiment for hydrogen isotope separation was carried out using a hydrogen-helium gas mixture. The hydrogen transport pipe has a potential for isotope separation and purification of hydrogen, deuterium and tritium in fusion reactor technology. (author)

Effect of coexistent hydrogen isotopes on tracer diffusion of tritium in alpha phase of group-V metal-hydrogen systems

International Nuclear Information System (INIS)

Sakamoto, Kan; Hashizume, Kenichi; Sugisaki, Masayasu

2009-01-01

Tracer diffusion coefficients of tritium in the alpha phase of group-V metal-hydrogen systems, α-MH(D)xTy (M=V and Ta; x>>y), were measured in order to clarify the effects of coexistent hydrogen isotopes on the tritium diffusion behavior. The hydrogen concentration dependence of such behavior and the effects of the coexistent hydrogen isotopes (protium and deuterium) were determined. The results obtained in the present (for V and Ta) and previous (for Nb) studies revealed that tritium diffusion was definitely dependent on hydrogen concentration but was not so sensitive to the kind of coexistent hydrogen isotopes. By summarizing those data, it was found that the hydrogen concentration dependence of the tracer diffusion coefficient of tritium in the alpha phase of group-V metals could be roughly expressed by a single empirical curve. (author)

Cytochrome P-450 dependent ethanol oxidation. Kinetic isotope effects and absence of stereoselectivity

International Nuclear Information System (INIS)

Ekstroem, G.; Norsten, C.; Cronholm, T.; Ingelman-Sundberg, M.

1987-01-01

Deuterium isotope effects [/sup D/(V/K)] and stereoselectivity of ethanol oxidation in cytochrome P-450 containing systems and in the xanthine-xanthine oxidase system were compared with those of yeast alcohol dehydrogenase. The isotope effects were determined by using both a noncompetitive method, including incubation of unlabeled of [1,1- 2 H 2 ] ethanol at various concentrations, and a competitive method, where 1:1 mixtures of [1- 13 C]- and [ 2 H 6 ] ethanol or [2,2,2- 2 H 3 ]- and [1,1- 2 H 2 ] ethanol were incubated and the acetaldehyde formed was analyzed by gas chromatography/mass spectrometry. The /sup D/(V/K) isotope effects of the cytochrome P-450 dependent ethanol oxidation were about 4 with liver microsomes from imidazole-, phenobarbital- or acetone-treated rabbits or with microsomes from acetone- or ethanol-treated rats. Similar isotope effects were reached with reconstituted membranes containing the rabbit ethanol-inducible cytochrome P-450 (LMeb), whereas control rat microsomes and membranes containing rabbit phenobarbital-inducible P-450 LM 2 oxidized the alcohol with /sup D/(V/K) of about 2.8 and 1.8, respectively. Addition of Fe/sup III/EDTA either to microsomes from phenobarbital-treated rabbits or to membranes containing P-450 LMeb significantly lowered the isotope effect. Incubations of all cytochrome P-450 containing systems of the xanthine-xanthine oxidase systems with (1R)- and (1S)-[1- 2 H] ethanol, revealed, taking the isotope effects into account, that 44-66% of the ethanol oxidized had lost the 1-pro-R hydrogen. The data indicate that cytochrome P-450 dependent ethanol oxidation is not stereospecific and that cleavage of the C 1 -H bond appears to be a rate-determining step in the catalysis by the ethanol-inducible form of P-450. The contribution of hydroxyl radicals in ethanol oxidation by the various enzymic systems is discussed

The deuterium depleted water effects on germination, growth and respiration processes in Zea Mays culture

International Nuclear Information System (INIS)

Stefanescu, Ioan; Fleancu, Monica; Giosanu, Daniela; Iorga-Siman, Ion

2002-01-01

The aim of this paper is to study the influence of deuterium depleted water (DDW) on the germination, growth and respiration processes in Zea Mays culture. The DDW is produced by the Institute of Cryogenics and Isotope Separation, Rm. Valcea (Romania). We used moist seeds in three experimental lots: L-1 (control), using distillated water (because the quality of DDW, excepting the deuterium content, is similar to that of distillated water); L-2, using a mixture of DDW and H 2 O in 1:1 proportion; L-3, germination in light water (DDW). Reported to the control lot, the germinative energy was higher in L-2 and L-3, but it was no significant difference between faculty of germination of variants. The length of main root was higher in L-2 and L-3 as compared to control lot. The intensity process of respiration was stimulated when DDW was used in both cases (L-2 or L-3). So, we can remark a favorable influence of light water on some biological processes in Zea mays plants (authors)

Charge exchange of excited mesic atoms of hydrogen isotopes in triple collisions with molecules

International Nuclear Information System (INIS)

Men'shikov, L.I.; Ponomarev, L.I.

1985-01-01

At high densities of deuterium-tritium mixture the probability for the occurrence of the isotope-exchange reaction (dμ)/sub n/+t → d+(tμ)/sub n/ from the excited states of n mesic atoms of deuterium is high in the triple collisions of mesic atoms with the molecules of hydrogen isotopes. This reaction should be taken into account in describing the kinetics of muon catalysis

Thermal x-rays and deuterium production in stellar flares

International Nuclear Information System (INIS)

Colgate, S.A.

1977-01-01

The x-ray spectrum of flares is shown to be necessarily thermal up to greater than or equal to 200 keV because the self magnetic field of any electron stream required for a thick or thin target source is inconsistently large. The resulting flare model can then be related to stellar luminosity, convection and magnetic fields to result in a maximum possible γ-burst (Mullan, 1976) and continuous x-ray flux. One of the most striking isotopic anomalies observed is the extreme enrichment of Helium (3) in some solar flares and the mysterious depletion of deuterium. It is discussed how deuterium may be produced and emitted in the largest flares associated with γ-bursts but in amounts insufficient to support the tentative conclusion of Colemen and Worden

Stable Isotopic Composition of Rainfall in Western Cameroon

Energy Technology Data Exchange (ETDEWEB)

Ketchemen-Tandia, B.; Ngo Boum, S.; Ebonji Seth, C. R.; Nkoue Ndong, G. R.; Wonkam, C. [Universite de Douala, Douala (Cameroon); Huneau, F. [Universite de Bordeaux, EA Georessources and Environnement, Talence (France); Celle-Jeanton, H. [Clermont Universite, Clermont-Ferrand (France)

2013-07-15

Monthly rainfall collected at the douala station (Western cameroon) from 2006 to 2008 was analysed for oxygen-18 and deuterium content. The dataset, which is now integrated into the GNIP database, was compared to the local groundwater record in order to define the input function of regional hydrosystems. The isotope data displays a wide range of values from -0.59 to -6.14 per mille for oxygen-18 and from -7.75 to -38.8 per mille for deuterium, closely following the GMWL (global Meteoric Water line), suggesting that rain formation processes occurred under isotopic equilibrium conditions between the condensate and the corresponding vapour. No significant evaporation tendency was found. The comparison with the previous studies in the area provides a realistic pattern of isotope concentrations in both surface and groundwater throughout Cameroon. (author)

Hydrogen isotope exchange reaction rates in tritium, hydrogen and deuterium mixed gases

International Nuclear Information System (INIS)

Uda, Tatsuhiko

1992-01-01

Hydrogen isotope exchange reaction rates in H 2 +T 2 , D 2 +T 2 and H 2 +D 2 +T 2 mixed gases, as induced by tritium decay and beta radiation, were experimentally measured by laser Raman spectrometry. Initially a glass cell was filled with T 2 gas to a pressure of 30-40 kPa, and an equivalent partial pressure of H 2 and/or D 2 was added. The first-order hydrogen isotope exchange reaction rates were 5.54x10 -2 h -1 for H 2 +T 2 mixed gas and 4.76x10 -2 h -1 for D 2 +T 2 . The actual HT producing rate was nearly equivalent to the rate of DT, but the reverse reaction rate of HT was faster than that of DT. The exchange reaction rates between H, D and T showed the isotope effect, HD>HT>DT. The hydrogen isotope exchange reaction rates observed were about twenty times larger than ion formation rates by beta radiation. This result suggests that a free radical chain reaction in hydrogen isotopes is occurring. (orig.)

The effects of environmental deuterium on normal and neoplastic cultured cell development

International Nuclear Information System (INIS)

Bild, W.; Schuller, T.; Zhihai, Qin; Blankenstein, T.; Nastasa, V.; Haulica, I.

2000-01-01

The powdered culture media (RPMI - 1640) were reconstituted either with normal distilled water (150 ppm deuterium) either with deuterium - depleted water (DDW) in various concentrations (30, 60, 90 ppm) and sterilized by filtration with 0.2 μm filters. The cell lines used were NIH (normal mouse fibroblasts), RAG (mouse renal carcinoma) and TS/A (mouse mammary adenocarcinoma). In auxiliary tests, BAIBC mouse splenocytes in direct culture were used, stimulated for growth with concanavalin A or LPS (bacterial lipopolysaccharide). The estimation of the growth was made using the MTT assay or direct counting with trypan blue exclusion. The following results were obtained: Deuterium - depleted water had a stimulating effect on cell growth, the most important stimulating action being from the 90 ppm deuterium-water. The growth curves show, in a first phase, a stimulation of the rapid -growing neoplastic cells, followed by a slower growth of the normal cells. Amiloride 100 mM blocking of the Na + /K + membrane pump did not affect the cell growth curves, while the lansoprazole 100 mM blocking of the K + /H + ATP-ase brought the growth curves at the level of those with normal water. This might show an eventual involvement of the K + /H + antiport in the stimulating effects of the DDW. (authors)

Synthesis of deuterium labelled cocaine and pseudococaine

International Nuclear Information System (INIS)

Casale, J.F.; Raney, H.T.; Cooper, D.A.

1991-01-01

Cocaine and pseudococaine were mass-labelled with deuterium at various positions on the tropane ring. The synthetic procedures followed were adaptations of those previously published for the unlabelled compounds. The isotopic purity was greater than 95% for 2-[ 2 H]-, 4,4-[ 2 H2]-, and 1,5,6,6,7,7-[ 2 H6]-cocaine and 3-[ 2 H]-, 4,4-[ 2 H2]-, and 1,5,6,6,7,7-[ 2 H6]-pseudococaine, while that of 3-[ 2 H]-cocaine exceeded 90%. (author)

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

Science.gov (United States)

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.

APPLICATION OF THE NATURALLY-OCCURRING DEUTERIUM ISOTOPE TO TRACING THE CAPILLARY FRINGE

Science.gov (United States)

Naturally-occurring deuterium is a useful tracer of subsurface hydrologic processes. A possible application includes the identification of capillary fringes in the vadose zone. Multiple and discontinuous water tables persist in many temperate regions, under various hydrogeologi...

Sulfur and Hydrogen Isotope Anomalies in Meteorite Sulfonic Acids

Science.gov (United States)

Cooper, George W.; Thiemens, Mark H.; Jackson, Teresa L.; Chang, Sherwood

1997-01-01

Intramolecular carbon, hydrogen, and sulfur isotope ratios were measured on a homologous series of organic sulfonic acids discovered in the Murchison meteorite. Mass-independent sulfur isotope fractionations were observed along with high deuterium/hydrogen ratios. The deuterium enrichments indicate formation of the hydrocarbon portion of these compounds in a low-temperature environment that is consistent with that of interstellar clouds. Sulfur-33 enrichments observed in methanesulfonic acid could have resulted from gas-phase ultraviolet irradiation of a precursor, carbon disulfide. The source of the sulfonic acid precursors may have been the reactive interstellar molecule carbon monosulfide.

Melatonin labeled with hydrogen isotopes

International Nuclear Information System (INIS)

Dmitrevskaya, L.I.; Smushkevich, Yu.I.; Kurkovskaya, L.N.; Ponomarenko, N.K.; Suvorov, N.N.

1989-01-01

A study has been made of isotope exchange between melatonin and deuterium (D 2 O) or tritium (HTO) oxide under different conditions. The ease of isotope exchange for the indole ring hydrogens of melatonin in an acidic medium decreases over the series H 4 > H 2 H 6 >> H 7 , enabling the authors to process a route for production of melatonin labeled with hydrogen isotopes at positions 4,6, and 2 of the indole ring. A method has been suggested for producing melatonin labeled with hydrogen isotopes at position 2 by desulfurization of 2-(2,4-dinitro-phenylsulfenyl)melatonin at Ni(Re) (D)

Melatonin labelled by hydrogen isotopes

International Nuclear Information System (INIS)

Dmitrevskaya, L.I.; Smushkevich, Yu.I.; Kurkovskaya, L.N.; Ponomarenko, N.K.; Suvorov, N.N.

1988-01-01

Isotope exchange of melatonin with deuterium (D 2 O) and tritium (HTO) oxides under different conditions is studied. Simplicity of isotope exchange of hydrogens of the indole ring of melatonin in the acidic medium decreases in series H 4 >H 2 >H 6 >>H 7 , that permits to suggest the way of melatonin preparation labelled by hydrogen isotopes in positions 4,6 and 2 of the indole ring. The way of melatonin preparation labelled by hydrogen isotopes in position 2 according to the reaction of desulfation 2-(2,4-dinitrophenylsulphenyl) melatonin at catalyst Ni(Re)(D) is suggested

Diffusion of hydrogen, deuterium, and tritium in niobium

International Nuclear Information System (INIS)

Matusiewicz, G.R.

1981-01-01

The diffusion of hydrogen in niobium was investigated over the temperature range 148 to 500 degrees Kelvin, using measurements of the elastic after effect caused by long range diffusion (the Gorsky Effect). Relaxation curves for pure annealed niobium were generally not of the single exponential form expected from the Gorsky Effect theory, but were described well by a sum of two exponential curves with different amplitudes and relaxation times. The effects of oxygen and nitrogen interstitials on the diffusion were studied and were not in agreement with conventional trapping models. Deuterium and tritium diffusion in niobium were also studied, and a non-classical isotope effect was observed. Hydrogen diffusion coefficients in several Nb-Ta alloys were measured, and the diffusivity in all these alloys exhibited a non-Arrhenius temperature dependence. Experimental results were compared to several models for diffusion and trapping. A model is presented which can account for the form of the relaxation curves observed in pure, annealed niobium

The Effect of Isotopic Substitution on Quantum Proton Transfer Across Short Water Bridges in Biological Systems

Science.gov (United States)

Blazejewski, Jacob; Schultz, Chase; Mazzuca, James

2015-03-01

Many biological systems utilize water chains to transfer charge over long distances by means of an excess proton. This study examines how quantum effects impact these reactions in a small model system. The model consists of a water molecule situated between an imidazole donor and acceptor group, which simulate a fixed amino acid backbone. A one dimensional energy profile is evaluated using density functional theory at the 6-31G*/B3LYP level, which generates a barrier with a width of 0.6 Å and a height of 20.7 kcal/mol. Quantum transmission probability is evaluated by solving the time dependent Schrödinger equation on a grid. Isotopic effects are examined by performing calculations with both hydrogen and deuterium. The ratio of hydrogen over the deuterium shows a 130-fold increase in transmission probability at low temperatures. This indicates a substantial quantum tunneling effect. The study of higher dimensional systems as well as increasing the number of water molecules in the chain will be necessary to fully describe the proton transfer process. Alma College Provost's Office.

Treatment and storage of hydrogen isotopes

International Nuclear Information System (INIS)

Jung, H. S.; Lee, H. S.; An, D. H.; Kim, K. R.; Lee, S. H.; Choi, H. J.; Back, S. W.; Kang, H. S.; Eom, K. Y.; Lee, M. S.

2000-01-01

Storage of gaseous hydrogen isotopes in a cylinder is a well-established technology. However, Immobilization in the solid form is preferred for long-term storage of radioactive isotope gas because of the concern for leakage of the gas. The experimental thermodynamic p-c-T data show that Ti and U soak up hydrogen isotope gas at a temperature of a few hundred .deg. C and modest pressures. It was found that more hydrogen is dissolved in the metal than deuterium at constant pressure. Thus, the lighter isotope tends to be enriched in the solid phase

Isotope dependent, temperature regulated, energy repartitioning in a low-barrier, short-strong hydrogen bonded cluster

NARCIS (Netherlands)

Li, X. H.; Oomens, J.; Eyler, J. R.; Moore, D. T.; Iyengar, S. S.

2010-01-01

We investigate and analyze the vibrational properties, including hydrogen/deuterium isotope effects, in a fundamental organic hydrogen bonded system using multiple experimental (infrared multiple photon dissociation and argon-tagged action spectroscopy) and computational techniques. We note a

Isotope enrichment by electron spin resonance transitions of the intermediate radical pair

International Nuclear Information System (INIS)

Okazaki, M.; Shiga, T.; Sakata, S.; Konaka, R.; Toriyama, K.

1988-01-01

Microwave effects on the spin adduct yield were observed in the photoreduction of menadione in micellar solutions with ordinary sodium dodecyl sulfate (SDS), deuterium-labeled SDS, and a mixture of them. A large isotope effect was found in the microwave modulation of the spin adduct yield, which is due to the ESR transitions of the transient radical pair in the reaction. It is demonstrated for the first time that the microwave field can be used to enrich one of the isotopes which coexist in the system

Process for the preparation of deuterium enriched water in the production of hydrogen

International Nuclear Information System (INIS)

Mandrin, Ch.

1986-01-01

A synthesis gas facility is operated for n consecutive periods. During the first period excess feed water is added to the facility. The effluent from the resulting mixture is fed to a storage container. During the following n-1 operating periods the stored effluent water is used as feed for the synthesis gas facility. The effluent from each operating period is stored in layers with corresponding deuterium concentration in the storage container. The effluent from the last operating period involving the highest deuterium concentration is fed to a second container and from there to a heavy water production unit. In order to recuperate the deuterium contained in the gas mixture leaving the condensor (consisting of hydrogen, vapour and residual compounds), the mixture is fed to an exchange stage. There the mixture is isotopically exchanged with additional water in a cross flow whereby this water gets enriched in deuterium and is fed to the synthesis gas facility. The process leads to an improved yield of heavy water in the heavy water production facility

Hot vacuum extraction-isotopic dilution mass spectrometry for determination of hydrogen isotopes in zircaloys

International Nuclear Information System (INIS)

Shi, Y.; Leeson, P.K.; Wilkin, D.; Britton, A.; Macleod, R.

2016-01-01

A hot vacuum extraction-isotope dilution mass spectrometry (HVE-IDMS) was studied for determination of hydrogen isotopes in zirconium metal and alloys as nuclear reactor materials. A theoretical assessment of the completeness of the extraction of hydrogen isotopes under the chosen condition was carried out based on the hydrogen and deuterium solubility data for zirconium. The optimal isotopic spiking condition for conventional IDMS was further explored for the special case IDMS where the isotope abundance of the samples is varied and non-natural. Applying the optimal conditions, the accurate IDMS determination was realized. The agreement between the measured values and the certified or prepared values of standard reference materials and homemade standard materials validate the method developed. (author)

Determination of hydrogen/deuterium ratio with neutron measurements on MAST

Energy Technology Data Exchange (ETDEWEB)

Klimek, I., E-mail: iwona.klimek@physics.uu.se; Cecconello, M.; Ericsson, G. [Department of Physics and Astronomy, Uppsala University, Uppsala (Sweden); Sharapov, S. E.; Harrison, J. [CCFE, Culham Science Centre, Abingdon (United Kingdom)

2014-11-15

On MAST, compressional Alfvén eigenmodes can be destabilized by the presence of a sufficiently large population of energetic particles in the plasma. This dependence was studied in a series of very similar discharges in which increasing amounts of hydrogen were puffed into a deuterium plasma. A simple method to estimate the isotopic ratio n{sub H}/n{sub D} using neutron emission measurements is here described. The inferred isotopic ratio ranged from 0.0 to 0.6 and no experimental indication of changes in radial profile of n{sub H}/n{sub D} were observed. These findings are confirmed by TRANSP/NUBEAM simulations of the neutron emission.

Synthesis of deuterium labelled cocaine and pseudococaine

Energy Technology Data Exchange (ETDEWEB)

Casale, J.F.; Raney, H.T. (State Bureau of Investigation, Raleigh, NC (USA). Drug Chemistry Lab.); Lewin, A.H. (Research Triangle Inst., Research Triangle Park, NC (USA)); Cooper, D.A. (Drug Enforcement Administration, McLean, VA (USA))

1991-03-01

Cocaine and pseudococaine were mass-labelled with deuterium at various positions on the tropane ring. The synthetic procedures followed were adaptations of those previously published for the unlabelled compounds. The isotopic purity was greater than 95% for 2-({sup 2}H)-, 4,4-({sup 2}H2)-, and 1,5,6,6,7,7-({sup 2}H6)-cocaine and 3-({sup 2}H)-, 4,4-({sup 2}H2)-, and 1,5,6,6,7,7-({sup 2}H6)-pseudococaine, while that of 3-({sup 2}H)-cocaine exceeded 90%. (author).

Melting diagram of hydrogen-deuterium solutions for pressures up to 100 atm

International Nuclear Information System (INIS)

Bereznyak, N.G.; Sheinina, A.A.

1985-01-01

Curves of the onset of melting of hydrogen-deuterium solutions of three different concentrations versus the vapor pressure up to ∼140 atm are measured. The topology of the melting diagram of H 2 --D 2 solutions at elevated pressures is determined. The isotope separation coefficients between the liquid and solid phases are calculated

Application of environmental isotope tracing technology to geothermal geochemistry

International Nuclear Information System (INIS)

Shang Yingnan

2006-01-01

This paper reviews the recent application and development of environmental isotope tracing technology to geothermal geochemistry in the following aspects: gas isotopes (He, C) tracing of warm springs; H, O isotope tracing on the origin and cause of geothermal water, environmental isotope dating of geothermal water, and the advantage of excess parameter of deuterium (d) in geothermal research. The author also suggests that isotope method should combine with other geological methods to expand its advantage. (authors)

Body Mass Index and Body Composition with Deuterium in Costa Rican Children

International Nuclear Information System (INIS)

Quintana-Guzmán, E.; Salas-Chaves, M. D. P.

2015-01-01

Body Mass Index (BMI) has been adopted as international measure for measuring adiposity in children with the disadvantage that it varies with age, sex and sexual maturation with no differentiation between fat mass and mass free of grease. The analysis of body composition allow to know if the overweight is due to fatty tissue being the deuterium isotope dilution a validated reference method using Infrared Spectrometry Transformed of Fourier (FTIR). We studied a total 118 boys and girls from 6 to 9 years old getting the values of z score of BMI for age and percentage of fat mass by FTIR. The results obtained in this study demonstrated that Costa Rica does not escape to the global problem of childhood obesity founding by BMI 18.6% of overweight and 10% of obesity and by body composition 9% of overweight and 57% of obesity. Isotopic deuterium dilution method demonstrated in this study to be more suitable for the analysis of obesity and overweight in children since BMI presented false positive and false negative results giving less accurate information of adiposity of the subject. (author)

Complementarity of deuterium and tritium measurements to study hailstone formation. An example

International Nuclear Information System (INIS)

Jouzel, Jean.

1975-12-01

The complementarity of deuterium and tritium measurement to study hailstone formation is presented and this method is applied to measurements made on three hailstones produced during a storm on August 7th 1971 in the province of Alberta (Canada). Firstly, the isotopic variations of condensed water in a hail cloud are studied on the basis of a cloud model as proposed by Chisholm. The importance of tritium analysis is demonstrated and conditions of validity of the isotopic model proposed by Merlivat, Nief and Roth in the case of deuterium are defined. The tritium measurement method used for analysis of small water samples and carrier out with an Oeschgger gas counter is described. The results connected with three Alberta hailstones are discussed. It is demonstrated particularly that these hailstones were formed during a succession of upward and downward movements, at least two of the latter occuring in the updraft core, and that the distribution of the updraft velocity with altitude was not stable during the storm which is in agreement with its multicellular nature [fr

Normalization of oxygen and hydrogen isotope data

Science.gov (United States)

Coplen, T.B.

1988-01-01

To resolve confusion due to expression of isotopic data from different laboratories on non-corresponding scales, oxygen isotope analyses of all substances can be expressed relative to VSMOW or VPDB (Vienna Peedee belemnite) on scales normalized such that the ??18O of SLAP is -55.5% relative to VSMOW. H3+ contribution in hydrogen isotope ratio analysis can be easily determined using two gaseous reference samples that differ greatly in deuterium content. ?? 1988.

Stable isotopes - separation and application

International Nuclear Information System (INIS)

Lockhart, I.M.

1980-01-01

In this review, methods used for the separation of stable isotopes ( 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, 18 O, 34 S) will be described. The synthesis of labelled compounds, techniques for detection and assay, and areas of application will also be discussed. Particular attention will be paid to the isotopes of carbon, nitrogen, and oxygen; to date, sulphur isotopes have only assumed a minor role. The field of deuterium chemistry is too extensive for adequate treatment; it will therefore be essentially excluded. (author)

Mixing rules for and effects of other hydrogen isotopes and of isotopic swamping on tritium recovery and loss to biosphere from fusion reactors

International Nuclear Information System (INIS)

Pendergrass, J.H.

1978-01-01

Efficient recovery of bred and unburnt tritium from fusion reactors, and control of its migration within reactors and of its escape into the biosphere are essential for self-sufficient fuel cycles and for public, plant personnel, and environmental protection. Tritium in fusion reactors will be mixed with unburnt deuterium and protium introduced by (n,p) reactions and diffusion into coolant loops from steam cycles. Rational design for tritium recovery and escape prevention must acknowledge this fact. Consequences of isotopic admixture are explored, mixing rules for projected fusion reactor dilute-solution conditions are developed, and a rule of thumb regarding their effects on tritium recovery methods is formulated

Hydrogen isotope separation in hydrophobic catalysts between hydrogen and liquid water

Energy Technology Data Exchange (ETDEWEB)

Ye, Linsen, E-mail: yls2005@mail.ustc.edu.cn [China Academy of Engineering Physics, Mianyang 621900 (China); Luo, Deli [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621907 (China); Tang, Tao; Yang, Wan; Yang, Yong [China Academy of Engineering Physics, Mianyang 621900 (China)

2015-11-15

Hydrogen isotope catalytic exchange between hydrogen and liquid water is a very effective process for deuterium-depleted potable water production and heavy water detritiation. To improve the characteristics of hydrophobic catalysts for this type of reaction, foamed and cellular structures of hydrophobic carbon-supported platinum catalysts were successfully prepared. Separation of deuterium or tritium from liquid water was carried out by liquid-phase catalytic exchange. At a gas–liquid ratio of 1.53 and exchange temperature of 70 °C, the theoretical plate height of the hydrophobic catalyst (HETP = 34.2 cm) was slightly lower than previously reported values. Changing the concentration of the exchange column outlet water yielded nonlinear changes in the height of the packing layer. Configurations of deuterium-depleted potable water and detritiation of heavy water provide references for practical applications.

Pressure dependent isotopic fractionation in the photolysis of formaldehyde-d2

DEFF Research Database (Denmark)

Nilsson, E.J.K.; Schmidt, Johan Albrecht; Johnson, Matthew Stanley

2014-01-01

role in the observed pressure dependent photolytic fractionation of deuterium. The model shows that part of the fractionation is a result of competition between the isotopologue dependent rates of unimolecular dissociation and collisional relaxation. We suggest that the remaining fractionation is due......The isotope effects in formaldehyde photolysis are the key link between the δD of methane emissions and the δD of atmospheric in situ hydrogen production. A few recent studies have suggested that a pressure dependence in the isotopic fractionation can partly explain enrichment of deuterium...... with altitude in the atmosphere. The mechanism and the extent of this pressure dependency is, however, not adequately described. In the present work D2CO and H2CO were photolyzed in a static reaction chamber at bath gas pressures of 50, 200, 400, 600 and 1000 mbar; these experiments compliment and extend our...

A Reexamination of Deuterium Fractionation on Mars

Science.gov (United States)

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

[Fractionation of hydrogen stable isotopes in the human body].

Science.gov (United States)

Siniak, Iu E; Grigor'ev, A I; Skuratov, V M; Ivanova, S M; Pokrovskiĭ, B G

2006-01-01

Fractionation of hydrogen stable isotopes was studied in 9 human subjects in a chamber with normal air pressure imitating a space cabin. Mass-spectrometry of isotopes in blood, urine, saliva, and potable water evidenced increases in the contents of heavy H isotope (deuterium) in the body liquids as compared with water. These results support one of the theories according to which the human organism eliminates heavy stable isotopes of biogenous chemical elements.

Characterization of a deuterium-deuterium plasma fusion neutron generator

Science.gov (United States)

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.

Homogeneous catalysis of deuterium transfer by potassium hydroxide and potassium methoxide D2-H2O and D2-CH3OH exchange

International Nuclear Information System (INIS)

Strathdee, G.G.; Garner, D.M.; Given, R.M.

1977-01-01

The kinetics and mechanism of exchange of deuterium between D 2 and water and between D 2 and methanol, catalyzed respectively by concentrated potassium hydroxide and potassium methoxide, has been studied between 348 and 398 K. In the D 2 -KOH-H 2 O case, the transfer of deuterium was found to be controlled by the rate of activation of the D 2 molecule by OH - . Rapid exchange of D + with the aqueous solution followed. From the D 2 -KOCH 3 -CH 3 OH studies, it was concluded that deuterium exchange depended upon the rates of both D 2 activation by methoxide and interaction of the solvent with the transition, or encounter, complex. The dependence of second-order rate constants on solvent activity for both systems was determined by normalization of the exchange reaction rates to unit reagent activity. Analysis of the kinetic isotope effects for each system suggested that their increase with base concentration or temperature was due to solvation effects. (author)

Separation of hydrogen isotopes for tritium waste removal

International Nuclear Information System (INIS)

Wilkes, W.R.

1975-01-01

A distillation cascade for separating hydrogen isotopes was simulated by means of a multicomponent, multistage computer code. A hypothetical test mixture containing equal atomic fractions of protium, deuterium and tritium, equilibrated to high temperature molecular concentrations was used as feed. The results show that a two-column cascade can be used to separate the protium from the tritium. Deuterium appears both in the protium and the tritium product streams. (auth)

Isotope exchange reactions on ceramic breeder materials and their effect on tritium inventory

Energy Technology Data Exchange (ETDEWEB)

Nishikawa, M; Baba, A [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering; Kawamura, Y; Nishi, M

1998-03-01

Though lithium ceramic materials such as Li{sub 2}O, LiAlO{sub 2}, Li{sub 2}ZrO{sub 3}, Li{sub 2}TiO{sub 3} and Li{sub 4}SiO{sub 4} are considered as breeding materials in the blanket of a D-T fusion reactor, the release behavior of the bred tritium in these solid breeder materials has not been fully understood. The isotope exchange reaction rate between hydrogen isotopes in the purge gas and tritium on the surface of breeding materials have not been quantified yet, although helium gas with hydrogen or deuterium is planned to be used as the blanket purge gas in the recent blanket designs. The mass transfer coefficient representing the isotope exchange reaction between H{sub 2} and D{sub 2}O or that between D{sub 2} and H{sub 2}O in the ceramic breeding materials bed is experimentally obtained in this study. Effects of isotope exchange reactions on the tritium inventory in the bleeding blanket is discussed based on data obtained in this study where effects of diffusion of tritium in the grain, absorption of water in the bulk of grain, and adsorption of water on the surface of grain, together with two types of isotope exchange reactions are considered. The way to estimate the tritium inventory in a Li{sub 2}ZrO{sub 3} blanket used in this study shows a good agreement with data obtained in such in-situ experiments as MOZART, EXOTIC-5, 6 and TRINE experiments. (author)

Permeability of hydrogen isotopes through Pd-Ag membrane

International Nuclear Information System (INIS)

Yoshida, Hiroshi

1981-01-01

This paper represents the permeabilities, diffusion coefficients and isotope effects for hydrogen and deuterium through Pd-25 wt.% Ag alloy tubes The feed gas H 2 or D 2 flowing into the permeation cell was preheated before it reached to the outer surface of the permeation tube made of palladium-silver alloy. Permeation time lag method could be successfully carried out with the present apparatus to measure both permeability and diffusion coefficient. The square-root pressure dependence for the permeation of hydrogen isotopes was observed. The observed systematic temperature dependence indicates that the approximation of the Arrhenius' relation was effective within this experimental conditions. Some tendency of permeation fluxes in relation to the reciprocal temperature, 1/T, was seen. The permeability ratio was larger than the square root of isotopic mass ratio, and it decreased with temperature rise. On the contrary, the diffusion coefficient ratio was much smaller than the square root of isotopic mass ratio. (Kato, T.)

Studies on displacement behavior between hydrogen and deuterium in hydride column

International Nuclear Information System (INIS)

Lu Guangda; Li Gan; Jiang Guoqiang

2001-01-01

A series displacement experiments between hydrogen and deuterium in ZrCo, LaNi 5 , LaNi 4.7 Al 0.3 and Pd hydride column had been conducted at room temperature about. Results indicate that displacement characteristics related to factors such as temperature, gas flow rate, ratio surface area of solid phase and hydrogen isotope separation factor of the metal-hydrogen system. The palladium hydride have the best displacement characteristics, and LaNi 5 , LaNi 4.7 Al 0.3 and ZrCo are in the next places. Theoretical study reveals that the rule of the exchange reaction of hydrogen isotopes in gas-solid interface determines the displacement behavior and the displacing efficiency depends on exchange rate. The ideal stage mode could be used to describe the displacement breakthrough curve. The height equivalent to theoretical place (HETP) indicates the displacing effects. Also, the separation factor has a serious influence to HETP under the same condition

Definitive Insight into the Graphite Oxide Reduction Mechanism by Deuterium Labeling

Czech Academy of Sciences Publication Activity Database

Jankovský, O.; Šimek, P.; Luxa, J.; Sedmidubský, D.; Tomandl, Ivo; Macková, Anna; Mikšová, Romana; Malinský, Petr; Pumera, M.; Sofer, Z.

2015-01-01

Roč. 80, č. 9 (2015), s. 1399-1407 ISSN 2192-6506 R&D Projects: GA ČR(CZ) GA15-09001S; GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : deuterium * graphene * isotopic labeling * reaction mechanisms * reduction Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.836, year: 2015

Synthesis of [methine-3H]DDT and its nitro-analog, and isotope effects in their enzyme-catalyzed dehydrochlorination

International Nuclear Information System (INIS)

Kurihara, N.; Ikemoto, Y.; Okutani, S.; Clark, A.G.

1989-01-01

[methine- 3 H]1,1-Di-(4-chlorophenyl)-2,2,2-trichloroethane ([methine- 3 H]DDT) and its di-(4-nitrophenyl) analog, both of high purity with a moderately high specific activity were prepared. Chloro-benzene was condensed with [1- 3 H]1-(4-chlorophenyl)-2,2,2-trichloro-ethanol, which has been synthesized by sodium boro[ 3 H]hydride reduction of 4-chlorophenyl trichloromethyl ketone. The purified [ 3 H]DDT had a specific activity of 0.77 Ci/mmol (28.49 GBq/mmol). [methine- 3 H]1,1-Diphenyl-2,2,2-trichloroethane was similarly synthesized and was nitrated to give [methine- 3 H]1,1-di-(4-nitrophenyl)-2,2,2-trichloro-ethane of 1.63 Ci/mmol (60.31 GBq/mmol). Dehydrochlorination with housefly enzyme (glutathione-dependent DDT dehydrochlorinase) showed a remarkable isotope effect. For DDT, the observed tritium isotope effect on V max /K m was 11.51±0.52. For the nitro-analog, the value was 11.3±1.2. We measured deuterium isotope effect on V max /K m for DDT in a competitive mode and obtained the value 4.19±0.34. Based on these values, the magnitude of intrinsic isotope effect values on DDT-dehydrochlorination reaction was discussed. (author)

Strong isotope effects on the charge transfer in slow collisions of He2+ with atomic hydrogen, deuterium, and tritium

NARCIS (Netherlands)

Stolterfoht, N.; Cabrera-Trujillo, R.; Oehrn, Y.; Deumens, E.; Hoekstra, R.; Sabin, J. R.

2007-01-01

Probabilities and cross sections for charge transfer by He2+ impact on atomic hydrogen (H), deuterium (D), and tritium (T) at low collision energies are calculated. The results are obtained using an ab initio theory, which solves the time-dependent Schrodinger equation. For the H target, excellent

Kinetics, isotope effects, and mechanism for the hydrogenation of carbon monoxide on supported nickel catalysts

International Nuclear Information System (INIS)

Mori, T.; Masuda, H.; Imai, H.; Miyamoto, A.; Baba, S.; Murakami, Y.

1982-01-01

Kinetics and hydrogen-deuterium isotope effects in the methanation of adsorbed CO molecules on a Ni/SiO 2 catalyst were precisely measured by using pulse surface reaction rate analysis (PSRA). When a CO pulse was injected into flowing hydrogen, it was immediately adsorbed on the catalyst and gradually hydrogenated to CH 4 and H 2 O. The amounts of CH 4 and H 2 O produced by the hydrogenation of the adsorbed CO were determined up to various times, and it was found that CH 4 and H 2 O were produced at the same rate. When O 2 instead of CO was injected, H 2 O was immediately produced. From these results, the rate-determining step of the reaction was found to be C-O bond dissociation of an adsorbed CO molecule or a partially hydrogenated CO species. By PSRA, the rate constant for the C-O bond dissocition process per adsorbed CO molecule (k/sub H/) was determined at various temperatures, and the Arrhenius parameters of the rate constant were obtained. The rate constant in flowing deuterium (k/sub D/) was also determined. it was found that k/sub D/ is considerably larger than k/sub H/, indicating an inverse isotope effect. The average value of k/sub H//k/sub D/ was 0.75. From these results, it was concluded that adsorbed CO is not directly dissociated to surface carbon and oxygen atoms but it is partially hydrogenated before C-O bond dissociation under the conditions of the PSRA experiment. 8 figures

Groundwater Resources Isotope Study of Eastern and Southeastern Areas of Jordan

International Nuclear Information System (INIS)

Al-Momani, M. R.

2004-01-01

Since Jordan depends on the groundwater resources especially for municipal use so, water resources studies and development takes priority on the national level. For this reason the environmental isotope technique and application contributed and supported the hydrological studies as a research tool confirmed some scientific facts including natural and environmental changes of water resources. The isotope analyses has been implemented for upper and deep aquifer systems in the eastern and southeastern areas of Jordan for Hamad, Sirhan, Azraq and Jafr basins. The analyses included the stable isotopes for 18 O, Deuterium ( 2 H) and 13 C also the radioactive isotopes for Tritium ( 3 H ) and 14 C in nineties of the last century until 2002 and this indicates the following: * The origin and mechanism of the nonrenewable groundwater recharge in the deep aquifer systems of (B2/A7) Campanian and Turonian age for Hamad and Azraq basins has been defined. This refers that the groundwater recharge existed within humid, cold and wet climatologic conditions which is completely different from the present climate where the groundwater age exceeds thirty thousand years. * Also this indicates that the stable isotopic composition of the upper aquifers in Hamad and Sirhan basins in Shallala and Rijam aquifers (B5/B4) of Eocene and Paleocene age lie on the Global Meteoric Water Line (GMWL) where the deuterium excess (d) is 10 %. Actually this water is not tritiated and the 14 C content in the groundwater is close to zero which is a strong indication of humid and wet climate where the age of the groundwater range between 20000 and exceeds 300000 years. In comparison this situation with the same aquifer in Jafr basin located in the southeastern part of Jordan, there are differences in the deuterium excess (d), Tritium and 14 C content which depends on the climatologic conditions existed during the recharge period. Also the isotopic signaure for the middle groundwater system (B2/A7) and the

Transport of negative hydrogen and deuterium ions in RF-driven ion sources

International Nuclear Information System (INIS)

Gutser, R; Wuenderlich, D; Fantz, U

2010-01-01

Negative hydrogen ion sources are major components of neutral beam injection systems for plasma heating in future large-scale fusion experiments such as ITER. In order to fulfill the requirements of the ITER neutral beam injection, a high-performance, large-area RF-driven ion source for negative ions is being developed at the MPI fuer Plasmaphysik. Negative hydrogen ions are mainly generated on a converter surface by impinging neutral particles and positive ions under the influence of magnetic fields and the plasma sheath potential. The 3D transport code TrajAn has been applied in order to obtain the total and spatially resolved extraction probabilities for H - and D - ions under identical plasma parameters and the realistic magnetic field topology of the ion source. A comparison of the isotopes shows a lower total extraction probability in the case of deuterium ions, caused by a different transport effect. The transport calculation shows that distortions of the spatial distributions of ion birth and extraction by the magnetic electron suppression field are present for both negative hydrogen and deuterium ions.

Competition H(D) kinetic isotope effects in the autoxidation of hydrocarbons.

Science.gov (United States)

Muchalski, Hubert; Levonyak, Alexander J; Xu, Libin; Ingold, Keith U; Porter, Ned A

2015-01-14

Hydrogen atom transfer is central to many important radical chain sequences. We report here a method for determination of both the primary and secondary isotope effects for symmetrical substrates by the use of NMR. Intramolecular competition reactions were carried out on substrates having an increasing number of deuterium atoms at symmetry-related sites. Products that arise from peroxyl radical abstraction at each position of the various substrates reflect the competition rates for H(D) abstraction. The primary KIE for autoxidation of tetralin was determined to be 15.9 ± 1.4, a value that exceeds the maximum predicted by differences in H(D) zero-point energies (∼7) and strongly suggests that H atom abstraction by the peroxyl radical occurs with substantial quantum mechanical tunneling.

Climate and isotopic tracers

International Nuclear Information System (INIS)

Jean-Baptiste, Ph.

1997-01-01

The applications of natural radioactivity and isotopic measurements in the sciences concerning Earth and its atmosphere, are numerous: carbon 14 dating with the Tandetron apparatus at the Cea, measurement of oxygen 18 in coral or sediment limestone for the determination of ocean temperature and salinity, carbon 14 dating of corals for the determination of sea level variations, deuterium content in polar ice-cap leads to temperature variations determination; isotopic measurements also enable the determination of present climate features such as global warming, oceanic general circulation

Wildcat: A commercial deuterium-deuterium tokamak reactor

International Nuclear Information System (INIS)

Evans, K.; Baker, C.C.; Barry, K.M.

1983-01-01

WILDCAT is a conceptual design of a catalyzed deuterium-deuterium tokamak commercial fusion reactor. WILDCAT utilizes the beneficial features of no tritium breeding, while not extrapolating unnecessarily from existing deuterium-tritium (D-T) designs. The reactor is larger and has higher magnetic fields and plasma pressures than typical D-T devices. It is more costly, but eliminates problems associated with tritium breeding and has tritium inventories and throughputs approximately two orders of magnitude less than typical D-T reactors. There are both a steady-state version with Alfven-wave current drive and a pulsed version. Extensive comparison with D-T devices has been made, and cost and safety analyses have been included. All of the major reactor systems have been worked out to a level of detail appropriate to a complete conceptual design

Use of isotope effects to characterize intermediates in mechanism-based inactivation of dopamine beta-monooxygenase by beta-chlorophenethylamine

International Nuclear Information System (INIS)

Bossard, M.J.; Klinman, J.P.

1990-01-01

A mechanism for beta-chlorophenethylamine inhibition of dopamine beta-monooxygenase has been postulated in which bound alpha-aminoacetophenone is generated followed by an intramolecular redox reaction to yield a ketone-derived radical cation as the inhibitory species. Based on the assumption that the ketone radical is the inhibitory intermediate, an analogous system was predicted and verified. In the present study, the role of alpha-aminoacetophenone as the proposed intermediate in the inactivation by beta-chlorophenethylamine was examined in greater detail. From the interdependence of tyramine and alpha-aminoacetophenone concentrations, ketone inactivation is concluded to occur at the substrate site as opposed to potential binding at the reductant-binding site. Using beta-[2-1H]- and beta-[2-2H]chlorophenethylamine, the magnitude of the deuterium isotope effect on inactivation under second-order conditions has been found to be identical to that observed under catalytic turnover, D(kappa inact/Ki) = D(kappa cat/Km) = 6-7. By contrast, the isotope effect on inactivation under conditions of substrate and oxygen saturation, D kappa inact = 2, is 3-fold smaller than that seen on catalytic turnover, D kappa cat = 6. This reduced isotope effect for inactivation is attributed to a normal isotope effect on substrate hydroxylation followed by an inverse isotope effect on the partitioning of the enol of alpha-aminoacetophenone between oxidation to a radical cation versus protonation to regenerate ketone. These findings are unusual in that two isotopically sensitive steps are present in the inactivation pathway whereas only one is observable in turnover

Biogeochemistry of the stable hydrogen isotopes

International Nuclear Information System (INIS)

Estep, M.F.; Hoering, T.C.

1980-01-01

The fractionation of H isotopes between the water in the growth medium and the organically bonded H from microalgae cultured under conditions, where light intensity and wavelength, temperature, nutrient availability, and the H isotope ratio of the water were controlled, is reproducible and light dependent. All studies were based either on the H isotope ratios of the total organic H or on the lipids, where most of the H is firmly bonded to C. H bonded into other macromolecules, proteins, carbohydrates and nucleic acids, does not exchange with water, when algae are incubated in water enriched with deuterium. Only after the destruction of quaternary H bonds are labile hydrogens in macromolecules free to exchange with water. By growing algae (18 strains), including blue-green algae, green algae and diatoms, in continuous light, the isotope fractionations in photosynthesis were reproducibly -93 to -178 per thousand, depending on the organism tested. This fractionation was not temperature dependent. Microalgae grown in total darkness with an organic substrate did not show the isotope fractionation seen in cells grown in light. In both light- and dark-grown algae, however, additional depletion of deuterium (-30 to -60 per thousand) in cellular organic matter occurs during the metabolism of carbohydrates to form lipids. Plants from several natural populations also fractionated isotopes during photosynthesis by an average of -90 to -110 per thousand. In addition, the organically bonded H in nonsaponifiable lipids was further fractionated by -80 per thousand from that in saponifiable lipids, isolated from two geographically distinct populations of marsh plants. This difference between H isotope ratios of these two groups of lipids provides an endogenous isotopic marker. (author)

Biogeochemistry of the stable hydrogen isotopes

Energy Technology Data Exchange (ETDEWEB)

Estep, M F; Hoering, T C [Carnegie Institution of Washington, DC (USA)

1980-08-01

The fractionation of H isotopes between the water in the growth medium and the organically bonded H from microalgae cultured under conditions, where light intensity and wavelength, temperature, nutrient availability, and the H isotope ratio of the water were controlled, is reproducible and light dependent. All studies were based either on the H isotope ratios of the total organic H or on the lipids, where most of the H is firmly bonded to C. H bonded into other macromolecules, proteins, carbohydrates and nucleic acids, does not exchange with water, when algae are incubated in water enriched with deuterium. Only after the destruction of quaternary H bonds are labile hydrogens in macromolecules free to exchange with water. By growing algae (18 strains), including blue-green algae, green algae and diatoms, in continuous light, the isotope fractionations in photosynthesis were reproducibly -93 to -178 per thousand, depending on the organism tested. This fractionation was not temperature dependent. Microalgae grown in total darkness with an organic substrate did not show the isotope fractionation seen in cells grown in light. In both light- and dark-grown algae, however, additional depletion of deuterium (-30 to -60 per thousand) in cellular organic matter occurs during the metabolism of carbohydrates to form lipids. Plants from several natural populations also fractionated isotopes during photosynthesis by an average of -90 to -110 per thousand. In addition, the organically bonded H in nonsaponifiable lipids was further fractionated by -80 per thousand from that in saponifiable lipids, isolated from two geographically distinct populations of marsh plants. This difference between H isotope ratios of these two groups of lipids provides an endogenous isotopic marker.

Applications of stable Isotope ratios determinations in fruit juice authentication

International Nuclear Information System (INIS)

Magdas, Dana Alina; Dehelean, Adriana; Voica, Cezara; Puscas, Romulus

2010-01-01

Full text: Adulteration of a product consists in making it impure by fraudulent addition of a foreign or inferior substance. The result is either an alteration of the product and of its quality or a falsification. The falsification is a voluntary act with the intention of abuse. The falsification may be more or less sophisticated and its sophistication as well as its costs increases with the improvement of analytical methods. Vacuum concentration with aroma does not affect the chemical composition of fruit juices and therefore the determination of deuterium (D) and oxygen-18 content in waters is the most confident procedure for differentiating between a natural single strength juice and a juice rediluted from a concentrate. This technique is based on the fact that when absorbed by a plant, the rainwater or the irrigation water is fractionated by evapotranspiration, and enriched in the heavy isotopes (deuterium and oxygen-18) with respect to the light isotope (hydrogen and oxygen-16, respectively). It is known that climatic conditions affect the isotope content of rain waters and therefore that of fruit juices waters: the warmer climate, the higher the deuterium and oxygen-18 contents in water. Rainwater and tap water have nearly the same isotopic content and the water of fruit juices derived from concentrate by dilution with tap water has an isotopic content close to that of tap water. This makes it easy to distinguish diluted concentrates from the isotopically more enriched water of authentic single strength juice. In this study, single strength juice, in Romanian fruits, were investigated by mean of stable isotope measurements (oxygen, hydrogen and carbon) in order to offer a discussion basis for the authenticity of some fruit juices currently available on Romanian market. (authors)

Hydrogen isotope effect on muonic x-ray spectra of (CH2)/sub x/ and H2O

International Nuclear Information System (INIS)

Mausner, L.F.; Knight, J.D.; Orth, C.J.; Schillaci, M.E.; Naumann, R.A.

1977-01-01

We have measured the muonic x-ray intensity patterns of C in (CH 2 )/sub x/ and (CD 2 )/sub x/ and of O in H 2 O and D 2 O. In both cases the relative intensities of the higher Lyman series members are significantly lower in the deuterium compounds, indicating that the initial angular momentum distribution of the muons captured on C and O is weighted to higher l states compared to the normal hydrogen compounds. This isotope effect has not been predicted by any model of negative-meson capture

Partial molar volumes of hydrogen and deuterium in niobium, vanadium, and tantalum

International Nuclear Information System (INIS)

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

1983-01-01

The partial molar volumes of hydrogen and deuterium were measured in vanadium, niobium, and tantalum by a differential pressure technique. One-half of an electrolytically charged sample plat was compressed between hardened steel blocks in a hydraulic press. The activity of hydrogen in the hig pressure region was raised and caused hydrogen to diffuse into the low pressure region. The partia molar volume was calculated from the ratio of the hydrogen concentrations in the high and low pressure regions of the sample. Small isotope effects were found in the partial molar volume. Hydrogen had the larger volume in niobium and tantalum, but the reverse was true in vanadium

Compared studies of natural and artificial deuterium depleted water

International Nuclear Information System (INIS)

Butnaru, Gallia; Mihacea, Sorina; Sirbovan, Alina; Butnariu, H.; Titescu, Gh.

2001-01-01

The biological influence of the deuterium on animals was studied insensitively in the last years. When animal cell cultures were analyzed it turned out an inhibition of the development, due to the reduced deuterium concentration. In the in vivo experiments a decreasing of the number of tumoral cells was pointed out when performing the depleted water treatment. It is obvious that the presence of deuterium in water is necessary for the development, especially for the tumoral cell proliferation. The aim of this work was to establish influence of the natural and artificial deuterium depleted water on the vegetal organisms development. For this purpose, the developmental stages of Lactuca sativa L. growth were followed. The experimental data were compared with the data obtained with distilled water. The birch, wine sap and some fruit juices are considered 'natural depleted' water sources because their deuterium content is smaller in comparison to natural water (D 2 =150 ppm). The effect of artificial deuterium depleted water (29 ppm D 2 ) was analyzed in comparison to three types of wine saps, which also have a reduced deuterium concentration (125-130 ppm D 2 ). If the deuterium depleted water was used, the germination percent and the root and shoot length were higher compared to control in the first stages. In wine sap it had a negative effect on germination and development. After three days the plants were transferred to soil and their development was followed. The foliage area was larger for all of the experimental variants compared to control. The differences were without significance when deuterium depleted water was tested but they were high and very significant in case of wine sap. The experiment pointed out a stimulative effect of the artificial deuterium depleted water. In case of wine sap the effect was negative when the contact was direct, but the growth was stimulated after the stress cessation. The first ontogenetic stages were represented by direct action

Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling

Science.gov (United States)

Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Donohoe, Gregory C.; Valentine, Stephen J.

2016-03-01

Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H]2- ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H]3- ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H]2- ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H]3- ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented.

Isotopic perturbation of degeneracy. Carbon-13 nuclear magnetic resonance spectra of dimethylcyclopentyl and dimethylnorbornyl cations

International Nuclear Information System (INIS)

Saunders, M.; Telkowski, L.; Kates, M.R.

1977-01-01

The large chemical shifts in 13 C NMR were used to measure the deuterium induced splittings and shifts in the 1 H NMR spectra of dimethylcyclopentyl and dimethylnorbornyl cations, where the deuterium perturbs the degenerate equilibrium. The isotope splitting obtained are tabulated

Hydrogen isotope fractionation in methane plasma

OpenAIRE

Robert, François; Derenne, Sylvie; Lombardi, Guillaume; Hassouni, Khaled; Michau, Armelle; Reinhardt, Peter; Duhamel, Rémi; Gonzalez, Adriana; Biron, Kasia

2017-01-01

Large variations in light element isotope ratios (H, N, C) are routinely observed in meteorite organic matter. The origin of these so-called anomalies is not accounted for by the classical theory of isotope fractionation. In the case of H, micrometer-size areas within the insoluble organic matter (IOM) isolated from meteorites by acid treatment, exhibit extreme deuterium enrichment. They are generally interpreted as components exogenous to the solar system and attributed to surviving interste...

Stable isotope geochemistry of the Tongonan geothermal system, Leyte, Philippines

International Nuclear Information System (INIS)

Hulston, J.R.; Stewart, M.K.

1982-01-01

Stable isotope and geochemical data on samples from natural features, shallow wells and deep wells collected over a number of years from the Tongonan area of Leyte have been evaluated. The variations in the isotopic compositions of the thermal waters are used to describe natural processes occurring within the system. The effect of the ''excess enthalpy'' of the deep wells on the isotope data is formulated. Water from the deep Tongonan wells shows an oxygen-18 shift of 5 per mille, which is larger than at Wairakei and Broadlands, probably in part because of the high temperatures at Tongonan. Recent measurements indicate that the deuterium shift is very much smaller than previously thought. Isotopic measurements of methane in the gases suggests differing flows from the Eastern and Central Philippine faults

Ultraviolet radiation-damage absorption peak in solid deuterium-tritium. Revision 1

International Nuclear Information System (INIS)

Fearon, E.M.; Tsugawa, R.T.; Souers, P.C.; Poll, J.D.; Hunt, J.L.

1985-01-01

An ultraviolet absorption peak has been seen in solid deuterium-tritium and hydrogen-tritium at a sensor temperature of 5 K. The peak occurs at 3.6 eV and is about 1.5 eV wide. It bleaches out when the temperature is raised to about 10 K but reappears upon cooling and is, therefore, radiation induced. At 5 K, the peak forms on a time scale of minutes and appears to represent part-per-million levels of electron-mass defects. The suggested model is that of a trapped electron, where the peak is the ground state-to-the-conduction band transition. A marked isotope effect is seen between D-T and H-T

The deuterium/hydrogen distribution in chondritic organic matter attests to early ionizing irradiation

Science.gov (United States)

Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Robert, François; Leroux, Hugues; Vezin, Hervé; Depecker, Christophe; Nuns, Nicolas; Lefebvre, Jean-Marc

2015-10-01

Primitive carbonaceous chondrites contain a large array of organic compounds dominated by insoluble organic matter (IOM). A striking feature of this IOM is the systematic enrichment in deuterium compared with the solar hydrogen reservoir. This enrichment has been taken as a sign of low-temperature ion-molecule or gas-grain reactions. However, the extent to which Solar System processes, especially ionizing radiation, can affect D/H ratios is largely unknown. Here, we report the effects of electron irradiation on the hydrogen isotopic composition of organic precursors containing different functional groups. From an initial terrestrial composition, overall D-enrichments and differential intramolecular fractionations comparable with those measured in the Orgueil meteorite were induced. Therefore, ionizing radiation can quantitatively explain the deuteration of organics in some carbonaceous chondrites. For these meteorites, the precursors of the IOM may have had the same isotopic composition as the main water reservoirs of the inner Solar System.

Solvent isotope effects on tautomerization equilibria of papain and model thiolamines

International Nuclear Information System (INIS)

Creighton, D.J.; Schamp, D.J.

1980-01-01

The state of ionization of the active site sulfhydryl group of papain at the pH-optimum of activity (pH approximately 6.5) remains a controversial issue. An alternative approach to the problem is reported here which utilizes the difference between the isotopic fractionation factor of the S-H bond (phi approximately equal to 0.4) and the N-H bond (phi = 0.97). In principle, the tautomerization equilibrium should be subject to an inverse solvent deuterium isotope effect in which the non-ionised form is more stable relative to the ionised form in D 2 O compared to H 2 O (K(H 2 O)/K(D 2 O) = phisub(SH)/phisub(MH) approximately equal to 0.4). This priniciple has been successfully tested on the tautomerization equilibria of cysteine and β-mercaptoethylamine from spectrophotometric titrations. To the extent that these simple thiolamines model the spectral properties of the tautomeric species envisioned in the active site of papain, the tautomerization equilibrium constant for papain is estimated (K(H 2 O) approximately equal to 2) from a comparison of the effect of solvent D 2 O on the mercaptide ion spectra of the thiolamines and the mercaptide ion-like difference absorption spectrum of papain. (Auth.)

Production of hydrogen and deuterium negative ions in an electron cyclotron resonance driven plasma

Energy Technology Data Exchange (ETDEWEB)

Dougar-Jabon, V.D. [Industrial Univ. of Santander, Bucaramanga (Colombia)

2001-04-01

An electron cyclotron resonance source with driven plasma rings for hydrogen isotope ion production is studied. Extracted currents of positive and negative ions depending on gas pressure, microwave power value and extraction voltage are obtained. The study shows that the negative ion yield is an order of magnitude higher than the yield of positive particles when a driven ring is in contact with the surface of the plasma electrode. The production of negative ions of deuterium, D{sup -}, is close to the production of negative ions of light hydrogen isotope, H{sup -}. The comparison of the experimental data with the calculated ones shows that the most probable process of the H{sup -} and D{sup -} ion formation in the electron cyclotron driven plasma is dissociative attachment of electrons to molecules in high Rydberg states. For hydrogen ions and ions of deuterium, the negative current at a microwave power of 200 W through a 3-mm aperture and 8 kV extraction voltage are 4.7 mA and 3.1 mA respectively. (orig.)

Production of hydrogen and deuterium negative ions in an electron cyclotron resonance driven plasma

International Nuclear Information System (INIS)

Dougar-Jabon, V.D.

2001-01-01

An electron cyclotron resonance source with driven plasma rings for hydrogen isotope ion production is studied. Extracted currents of positive and negative ions depending on gas pressure, microwave power value and extraction voltage are obtained. The study shows that the negative ion yield is an order of magnitude higher than the yield of positive particles when a driven ring is in contact with the surface of the plasma electrode. The production of negative ions of deuterium, D - , is close to the production of negative ions of light hydrogen isotope, H - . The comparison of the experimental data with the calculated ones shows that the most probable process of the H - and D - ion formation in the electron cyclotron driven plasma is dissociative attachment of electrons to molecules in high Rydberg states. For hydrogen ions and ions of deuterium, the negative current at a microwave power of 200 W through a 3-mm aperture and 8 kV extraction voltage are 4.7 mA and 3.1 mA respectively. (orig.)

Environmental isotope hydrology

International Nuclear Information System (INIS)

1973-01-01

Environmental isotope hydrology is a relatively new field of investigation based on isotopic variations observed in natural waters. These isotopic characteristics have been established over a broad space and time scale. They cannot be controlled by man, but can be observed and interpreted to gain valuable regional information on the origin, turnover and transit time of water in the system which often cannot be obtained by other techniques. The cost of such investigations is usually relatively small in comparison with the cost of classical hydrological studies. The main environmental isotopes of hydrological interest are the stable isotopes deuterium (hydrogen-2), carbon-13, oxygen-18, and the radioactive isotopes tritium (hydrogen-3) and carbon-14. Isotopes of hydrogen and oxygen are ideal geochemical tracers of water because their concentrations are usually not subject to change by interaction with the aquifer material. On the other hand, carbon compounds in groundwater may interact with the aquifer material, complicating the interpretation of carbon-14 data. A few other environmental isotopes such as 32 Si and 238 U/ 234 U have been proposed recently for hydrological purposes but their use has been quite limited until now and they will not be discussed here. (author)

Application of Deuterium and Oxygen-18 to Trace Leachate Movement in Bantar Gebang Sanitary Landfill

International Nuclear Information System (INIS)

Pujiindiyati, E.R.

2011-01-01

Bantar Gebang landfill was constructed in 1986 with total area of 108 ha and approximately 6000 ton/day solid waste is disposed to this landfill. Mostly, the people living surrounding landfill get afraid of impact of the hazardous chemicals produced by waste disposal to their health. The purpose of this investigation was to study the migration of leachate to Cibitung River water and shallow groundwaters near to the river. It is possible to be done because chemical contents and isotopic characteristics of municipal landfill leachate are unique, relative to aqueous media in the most natural environments. Laser absorption method developed by the LGR (Los Gatos Research) was used to measure absolute abundances of 2 HHO, HH 18 O and HHO in a number of water samples. In-situ measurements were also conducted as an additional parameter besides their isotopes. The δ 2 H of the H 2 O in landfill leachate was significantly enriched, with values of - 22.6 0/00 to + 4.3 0/00. This deuterium enrichment was undoubtedly due to the extensive production of microbial methane within the limited reservoir of the landfill. However, the enriched deuterium value in leachate was not detected in the river which still had depleted values. It was probably caused by the amount of natural water in the river was comparatively large, with respect to limited leachate discarded to the river. The electrical conductivity of the leachate was higher (3200 to 7600 μS) and the decreasing values were still monitored in the river to approximately 12 km after streaming the landfills. The effect of the high electrical conductivity and enriched deuterium of leachate was not clearly indicated in the groundwater samples which still represented the local precipitation recharge, except a monitoring well located in Bantar Gebang landfill area which has an indication of leachate contamination. (author)

Application of Deuterium and Oxygen-18 to Trace Leachate Movement in Bantar Gebang Sanitary Landfill

Directory of Open Access Journals (Sweden)

E.R. Pujiindiyati

2011-08-01

Full Text Available Bantar Gebang landfill was constructed in 1986 with total area of 108 ha and approximately 6000 ton/day solid waste is disposed to this landfill. Mostly, the people living surrounding landfill get afraid of impact of the hazardous chemicals produced by waste disposal to their health. The purpose of this investigation was to study the migration of leachate to Cibitung River water and shallow groundwaters near to the river. It is possible to be done because chemical contents and isotopic characteristics of municipal landfill leachate are unique, relative to aqueous media in the most natural environments. Laser absorption method developed by the LGR (Los Gatos Research was used to measure absolute abundances of 2HHO, HH18O and HHO in a number of water samples. In-situ measurements were also conducted as an additional parameter besides their isotopes. The δ2H of the H2O in landfill leachate was significantly enriched, with values of - 22.6 ‰ to + 4.3 ‰. This deuterium enrichment was undoubtedly due to the extensive production of microbial methane within the limited reservoir of the landfill. However, the enriched deuterium value in leachate was not detected in the river which still had depleted values. It was probably caused by the amount of natural water in the river was comparatively large, with respect to limited leachate discarded to the river.The electrical conductivity of the leachate was higher (3200 to 7600 S and the decreasing values were still monitored in the river to approximately 12 km after streaming the landfills. The effect of the high electrical conductivity and enriched deuterium of leachate was not clearly indicated in the groundwater samples which still represented the local precipitation recharge, except a monitoring well located in Bantar Gebang landfill area which has an indication of leachate contamination.

Isotope effect studies of chicken liver NADP malic enzyme: role of the metal ion and viscosity dependence

International Nuclear Information System (INIS)

Grissom, C.B.; Cleland, W.W.

1988-01-01

The role of the metal ion in the oxidative decarboxylation of malate by chicken liver NADP malic enzyme and details of the reaction mechanism have been investigated by 13 C isotope effects. With saturating NADP and the indicated metal ion at a total concentration 10-fold higher than its K/sub m/, the following primary 13 C kinetic isotope effects at C 4 of malate [ 13 (VK/sub mal/)] were observed at pH 8.0: Mg 2+ , 1.0336; Mn 2+ , 1.0365; Cd 2+ , 1.0366; Zn 2+ , 1.0337; Co 2+ , 1.0283; Ni 2+ , 1.025. Knowing the partitioning of the intermediate oxalacetate between decarboxylation to pyuvate and reduction to malate allows calculation of the intrinsic carbon isotope effect for decarboxylation to pyuvate and reduction to malate allows calculation of the intrinsic carbon isotope effect for decarboxylation. For Mg 2+ as activator, this was 1.049 with NADP and 1.046 with 3-acetylpyridine adenine dinucleotide phosphate, although the intrinsic primary deuterium isotope effects on dehydrogenation were 5.6 and 4.2, and the partition ratios of the oxalacetate intermediate for decarboxylation as opposed to hydride transfer were 0.11 and 3.96. It was not possible to calculate reasonable intrinsic carbon isotope effects with the other metal ions by use of the partitioning ratio of oxalacetate because of decarboxylation by another mechanism. The variation of 13 (VK/sub mal/) with pH was used to dissect the total forward and external components. When the authors attempted to use the variation of 13 (VK/sub mal/) with solution viscosity to determine the internal and external commitments, incorrect values were obtained because of a specific effect of the viscosogen in decreasing the K/sub m/ for malate, so that VK/sub mal/ actually increased with viscosity instead of decreasing, as theory predicts

Deuterium exchange between hydrofluorocarbons and amines

International Nuclear Information System (INIS)

Hammond, W.B.; Bigeleisen, J.; Tuccio, S.A.

1983-01-01

The invention consists of a process for obtaining a compound enriched in deuterium which comprises the known method of exposing a gaseous hydrofluorocarbon to infrared laser radiation of a predetermined frequency to selectively cause a chemical reaction involving hydrofluorocarbon molecules containing deuterium without substantially affecting hydrofluorocarbon molecules not containing deuterium, thereby producing, as reaction products, a compound enriched in deuterium and hydrofluorocarbon depleted in deuterium; combined with a new method, which comprises enriching the deuterium content of the depleted hydrofluorocarbon by contacting the depleted hydrofluorocarbon with an alkali metal amide and an amine having a concentration of deuterium at least that which will yield an increase in deuterium concentration of the hydrofluorocarbon upon equilibration, whereby the amine becomes depleted in deuterium

Isotope effect and isotope separation. A chemist's view

International Nuclear Information System (INIS)

Ishida, Takanobu

2002-01-01

What causes the isotope effects (IE)? This presentation will be centered around the equilibrium isotope effects due to the differences in the nuclear masses. The occurrence of the equilibrium constant, K, of isotope exchange reactions which differ from the values predicted by the classical theory of statistical mechanics, K cl , is explored. The non-classical K corresponds to the unit-stage separation factor, α, that is different from unity and forms a basis of an isotope separation process involving the chemical exchange reaction. Here, the word 'chemical exchange' includes not only the isotope exchange chemical reactions between two or more chemical species but also the isotope exchanges involving the equilibria between liquid and vapor phases and liquid-gas, liquid solution-gas, liquid-liquid, and solid-liquid phases. In Section I, origins of the isotope effect phenomena will be explored and, in the process, various quantities used in discussions of isotope effect that have often caused confusions will be unambiguously defined. This Section will also correlate equilibrium constant with separation factor. In Section II, various forms of temperature-dependence of IE and separation factor will be discussed. (author)

Deuterium- and tritium-labelled compounds. Applications in the life sciences

International Nuclear Information System (INIS)

Atzrodt, Jens; Derdau, Volker; Kerr, William J.; Reid, Marc

2018-01-01

Hydrogen isotopes are unique tools for identifying and understanding biological and chemical processes. Hydrogen isotope labelling allows for the traceless and direct incorporation of an additional mass or radioactive tag into an organic molecule with almost no changes in its chemical structure, physical properties, or biological activity. Using deuterium-labelled isotopologues to study the unique mass-spectrometric patterns generated from mixtures of biologically relevant molecules drastically simplifies analysis. Such methods are now providing unprecedented levels of insight in a wide and continuously growing range of applications in the life sciences and beyond. Tritium ( 3 H), in particular, has seen an increase in utilization, especially in pharmaceutical drug discovery. The efforts and costs associated with the synthesis of labelled compounds are more than compensated for by the enhanced molecular sensitivity during analysis and the high reliability of the data obtained. In this review, advances in the application of hydrogen isotopes in the life sciences are described. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Estimating the contribution of preferential flow to subsurface runoff from a hillslope using deuterium and chloride

Science.gov (United States)

Leaney, F. W.; Smettem, K. R. J.; Chittleborough, D. J.

1993-06-01

The concentrations of deuterium and chloride in rainfall, soil water and throughflow are reported for flow components through a mid-level gently sloping hillside podzolic soil with a well developed network of macropores. The deuterium and chloride signatures of the throughflow are shown to resemble that of rainfall rather than soil water for all rainfall events. Flow through macropores is considered to be the major mechanism for infiltration and throughflow. During the initial stages of rainfall, infiltrating water bypasses much of the soil matrix and a transient water table is established. Storage associated with this water table dampens much of the noise from the deuterium and chloride signature of the rainfall while maintaining the mean rainfall signature. The possible implications on the use of stable isotopes and conservative tracers such as chloride for streamflow partitioning are discussed.

Intra-event isotope and raindrop size data of tropical rain reveal effects concealed by event averaged data

Science.gov (United States)

Managave, S. R.; Jani, R. A.; Narayana Rao, T.; Sunilkumar, K.; Satheeshkumar, S.; Ramesh, R.

2016-08-01

Evaporation of rain is known to contribute water vapor, a potent greenhouse gas, to the atmosphere. Stable oxygen and hydrogen isotopic compositions (δ18O and, δD, respectively) of precipitation, usually measured/presented as values integrated over rain events or monthly mean values, are important tools for detecting evaporation effects. The slope ~8 of the linear relationship between such time-averaged values of δD and δ18O (called the meteoric water line) is widely accepted as a proof of condensation under isotopic equilibrium and absence of evaporation of rain during atmospheric fall. Here, through a simultaneous investigation of the isotopic and drop size distributions of seventeen rain events sampled on an intra-event scale at Gadanki (13.5°N, 79.2°E), southern India, we demonstrate that the evaporation effects, not evident in the time-averaged data, are significantly manifested in the sub-samples of individual rain events. We detect this through (1) slopes significantly less than 8 for the δD-δ18O relation on intra-event scale and (2) significant positive correlations between deuterium excess ( d-excess = δD - 8*δ18O; lower values in rain indicate evaporation) and the mass-weighted mean diameter of the raindrops ( D m ). An estimated ~44 % of rain is influenced by evaporation. This study also reveals a signature of isotopic equilibration of rain with the cloud base vapor, the processes important for modeling isotopic composition of precipitation. d-excess values of rain are modified by the post-condensation processes and the present approach offers a way to identify the d-excess values least affected by such processes. Isotope-enabled global circulation models could be improved by incorporating intra-event isotopic data and raindrop size dependent isotopic effects.

Hot muonic deuterium and tritium from cold targets

International Nuclear Information System (INIS)

Marshall, G.M.; Beveridge, J.L.; Bailey, J.M.; Beer, G.A.; Knowles, P.E.; Mason, G.R.; Olin, A.; Brewer, J.H.; Forster, B.M.; Huber, T.M.; Pippitt, B.; Jacot-Guillarmod, R.; Schellenberg, L.; Martoff, C.J.; Petitjean, C.

1992-01-01

Experiments are described which use a solid hydrogen layer to form muonic hydrogen isotopes in vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to study the energy dependence of transfer and muon molecular formation

Isotope dilution analysis for urinary fentanyl and its main metabolite, norfentanyl, in patients by isotopic fractionation using capillary gas chromatography

Energy Technology Data Exchange (ETDEWEB)

Sera, Shoji; Goromaru, Tsuyoshi [Fukuyama Univ., Hiroshima (Japan). Faculty of Pharmacy and Pharmaceutical Sciences; Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

1998-07-01

Isotope dilution analysis was applied to determine urinary excretion of fentanyl (FT) and its main metabolite, norfentanyl (Nor-FT), by isotopic fractionation using a capillary gas chromatograph equipped with a surface ionization detector (SID). Urinary FT was determined quantitatively in the range of 0.4-40 ng/ml using deuterium labeled FT (FT-{sup 2}H{sub 19}), as an internal standard. We also performed isotope dilution analysis of Nor-FT in urine. N-Alkylation was necessary to sensitively detect Nor-FT with SID. Methyl derivative was selected from 3 kinds of N-alkyl derivatives to increase sensitivity and peak resolution, and to prevent interference with urinary compound. Nor-FT concentration was quantitatively determined in the range of 10-400 ng/ml using deuterium labeled Nor-FT (Nor-FT-{sup 2}H{sub 10}). No endogenous compounds or concomitant drugs interfered with the detection of FT and Nor-FT in the urine of patients. The present method will be useful for pharmacokinetic studies and the evaluation of drug interactions in FT metabolism. (author)

Isotope dilution analysis for urinary fentanyl and its main metabolite, norfentanyl, in patients by isotopic fractionation using capillary gas chromatography

International Nuclear Information System (INIS)

Sera, Shoji; Goromaru, Tsuyoshi; Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

1998-01-01

Isotope dilution analysis was applied to determine urinary excretion of fentanyl (FT) and its main metabolite, norfentanyl (Nor-FT), by isotopic fractionation using a capillary gas chromatograph equipped with a surface ionization detector (SID). Urinary FT was determined quantitatively in the range of 0.4-40 ng/ml using deuterium labeled FT (FT- 2 H 19 ), as an internal standard. We also performed isotope dilution analysis of Nor-FT in urine. N-Alkylation was necessary to sensitively detect Nor-FT with SID. Methyl derivative was selected from 3 kinds of N-alkyl derivatives to increase sensitivity and peak resolution, and to prevent interference with urinary compound. Nor-FT concentration was quantitatively determined in the range of 10-400 ng/ml using deuterium labeled Nor-FT (Nor-FT- 2 H 10 ). No endogenous compounds or concomitant drugs interfered with the detection of FT and Nor-FT in the urine of patients. The present method will be useful for pharmacokinetic studies and the evaluation of drug interactions in FT metabolism. (author)

Experimental investigation of H2/D2 isotope separation by cryo-adsorption in metal-organic frameworks

International Nuclear Information System (INIS)

Teufel, Julia Sonja

2012-01-01

Light-gas isotopes differ in their adsorption behavior under cryogenic conditions in nanoporous materials due to their difference in zero-point energy. However, the applicability of these cryo-effects for the separation of isotope mixtures is still lacking an experimental proof. The current work describes the first experimentally obtained H 2 /D 2 selectivity values of nanoporous materials measured by applying isotope mixtures in low-temperature thermal desorption spectroscopy (TDS). The dissertation contains the following key points: 1) A proof of the experimental method, i.e. it is shown that TDS leads to reasonable selectivity values. 2) A series of small-pore MFU-4 derivatives (MOFs) is shown to separate isotope mixtures by quantum sieving, i.e. by the difference in the adsorption kinetics. The influence of the pore size on the selectivity is studied systematically for this series. 3) Two MOFs with pores much larger than the kinetic diameter of H 2 do not exhibit kinetic quantum sieving. However, if the MOFs are exposed to an isotope mixture, deuterium adsorbs preferentially at the adsorption sites with high heats of adsorption. According to the experimental results, these strong adsorption sites can be every selective for deuterium. On the basis of the experimentally obtained selectivity values, technical implementations for H 2 /D 2 light-gas isotope separation by cryo-adsorption are described.

Energy Levels of Hydrogen and Deuterium

Science.gov (United States)

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.

The influence of variation of deuterium's concentration on the immunity system

International Nuclear Information System (INIS)

Tamaian, Radu

2007-01-01

Hydrogen's substitution by deuterium represents an environmental alteration at which the organism (in vivo) and the cells (in vitro), respectively, if they can't accommodate will recede. In this way the variations of deuterium's isotopic abundance can be compared with the environmental factors of stress (variations of temperature, quantity of nourishment, radiations, etc). As different forms of existence of life are more or less sensitive at environment's factors variations, so they respond in different ways to concentration variations of deuterium from the living environment/organism. Consequently the mammals' immunity system (IS) presents different feed-backs. The main results are stressed as follows: - a. The use as alimentary adjuvant of deuterium depleted water (DDW) in prolonged periods (21 days) increased the capacity of unspecific immunity defense against the specific bacterial aggression, both in Gram-positive bacteria (Streptococcus pneumoniae558) and of Gram-negative (Klebsiella pneumoniae507); - b. The immunosuppression determined by cyclophosphamide-alquilant agent with medullary depletion of white series reduced the survival of inoculated animals, even in the conditions in which the animals have received dietary supplement with DDW; - c. The immunosuppression through medullary depletion due to irradiation reduced also the survival of inoculated animals, even in the conditions in which the animals have received dietary supplement with DDW. Those mentioned herein lead to the hypothesis that prolonged administration of DDW simulates the unspecific immunity defence, probably through the stimulation of the hematogenic marrow and of lymphopoietic and granulopoietic stem cells. (author)

Hydrogen/deuterium fractionation factors of the aqueous ligand of cobalt in Co(H2O)62+ and Co(II)-substituted carbonic anhydrase

International Nuclear Information System (INIS)

Kassebaum, J.W.

1988-01-01

The author has measured the hydrogen/deuterium fractionation factor for the rapidly exchanging aqueous ligands of cobalt in Co(H 2 O) 6 2+ and in three Co(II)-substituted isozymes of carbonic anhydrase. The fractionation factor was determined from NMR relaxation rates at 300 MHz of the protons of water in mixed solutions of H 2 O and D 2 O containing these complexes. In each case, the paramagnetic contribution to 1/T 2 was greater than to 1/T 1 , consistent with a chemical shift mechanism affecting 1/T 2 . The fractionation factors obtained from T 2 were 0.73 ± 0.02 for Co(H 2 O) 6 2+ , 0.72 ± 0.02 for Co(II)-substituted carbonic anhydrase I, 0.77 ± 0.01 for Co(II)-substituted carbonic anhydrase II, and 1.00 ± 0.07 for Co(Il)-substituted carbonic anhydrase III. He concluded that fractionation factors in these cases determined from T 1 and T 2 measured isotope preferences for different populations of ligand sites. Since T 2 has a large contribution from a chemical shift mechanism, the fractionation factor determined from T 2 has a large contribution of the fractionation of inner shell ligands. The fractionation factor of Co(H 2 O) 6 2+ was used to interpret the solvent hydrogen isotope effects on the formation of complexes of cobalt with the bidentate ligands glycine, N,N-dimethylglycine, and acetylacetone. The contribution of the fractionation factor of the inner water shell in Co(H 2 O) 6 2+ did not account completely for the measured isotope effect, and that the hydrogen/deuterium fractionation of outer shell water makes a large contribution to the isotope effect on the formation of these complexes

Deuterium exchange reaction in a trickle bed packed with a mixture of hydrophobic catalyst and hydrophilic packings

International Nuclear Information System (INIS)

Seungwoo Paek; Heui-Joo Choi; DO-Hee Ahn; Kwang-Rag Kim; Minsoo Lee; Sung-Paal Yim; Hongsuk Chung

2006-01-01

Full text of publication follows: The isotopic exchange reaction between hydrogen and water on the platinum supported catalysts provides a useful step for separating hydrogen isotopes such as deuterium and tritium. The CECE (Combined Electrolysis Catalytic Exchange) with a hydrophobic catalyst is a very effective method to remove small quantities of tritium from light or heavy waste water streams because of its high separation factor and mild operating conditions. The CECE column is composed of an electrolysis cell and a liquid phase catalytic exchange column. This paper deals with the experiments for the hydrogen isotopic exchange reaction in a trickle bed reactor packed with a hydrophobic catalyst in order to develop the catalytic column of the CECE. Hydrophobic Pt/SDBC catalyst which has been developed for the LPCE column of WTRF (Wolsong Tritium Removal Facility) was tested in a trickle bed reactor. The catalyst column was packed with a mixture of hydrophobic catalyst and hydrophilic packing (Dixon gauze ring) to improve liquid distribution and vapor/liquid transfer area. An experimental apparatus was built for the test of the catalyst at various temperatures and gas velocities. The catalyst was packed wet into the column and water was injected at the top through a liquid distributor and trickled through a catalyst mixture. Hydrogen gas passed up the column and deuterium was transferred to water stream flowing counter currently. The temperature of the column was controlled to maintain at 60 deg. C using water jackets around the reactor and equilibrator, a feed waster heater, and a circulation water heater. A metal bellows pump was used to circulate the hydrogen gas at the typical flow rate of 60 LPM.The reactor pressure was controlled to maintain at 135 kPa (abs) by a water column. Gas samples were drawn off from the top and bottom of the column. The difference in deuterium concentration between the inlet and outlet gas samples was analyzed using Gas

Primary and secondary kinetic deuterium isotope effects and transition-state structures for benzylic chlorination and bromination of toluene

International Nuclear Information System (INIS)

Hanzlik, R.P.; Schaefer, A.R.; Moon, J.B.; Judson, C.M.

1987-01-01

As a chemical model for benzylic hydroxylation effects by cytochrome P-450 enzymes, the chlorination of PhCH 3 , PhCH 2 D, PhCHD 2 , and PhCD 3 in a two-phase system of hypochlorite/CH 2 Cl 2 with a phase-transfer catalyst has been investigated. On the basis of the deuterium content of the product benzyl chlorides, relative rate constants were deduced for all possible H- and D-abstractions with these substrates. From this the primary (P) and secondary (S) KDIEs were found to be 5.90 +/- 0.41 and 1.03 +/- 0.02, respectively, and the rule of the geometric mean was found to be closely obeyed. For the analogous bromination of toluene by N-bromosuccinimide in CCl 4 , P and S were 6.37 +/- 0.43 and 1.05 +/- 0.01. The transition states of these processes must therefore involve extensive C-H bond breaking but relatively little rehybridization toward planarity at the reacting carbon

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.

Science.gov (United States)

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.

Laser separation of isotopes of hydrogen

International Nuclear Information System (INIS)

Dave, S.M.; Ghosh, S.K.; Sadhukhan, H.K.

1980-01-01

Laser isotope separation technique is explained and various methods based on the technique are discussed in detail. Requirements of any laser isotope separation method to be acceptable for the production of heavy water are mentioned and economic viability of this process for heavy water production is examined. Investigations carried out to use this technique for deuterium separation using methanol, formaldehyde, propynal, 2,2,-dichloro-1-1-1,-trifluoroethane (Freon 123), polyvinyl chloride and fluoroform-d are reviewed. (M.G.B.)

Preliminary measurements of tritium, deuterium and oxygen-18 in lakes and groundwater of volcanic Rotorua region, New Zealand

International Nuclear Information System (INIS)

Taylor, C.B.; Freestone, H.J.; Nairn, I.A.

1977-06-01

This report presents an initial survey of the isotopic characteristics of non-hydrothermal waters of Rotorua region. Measurements of deuterium, oxygen and tritium have been made on samples collected between 1970 and 1973. Some major springs emerging close to land-locked lakes have been identified as containing mixtures of lake-derived water and precipitation-derived recharge in the catchments between lake and spring. The stable isotope composition of precipitation-recharged groundwater occupies a fairly narrow range, but is nevertheless seperable into two distinct isotopic families. The circumstances leading to these isotopic differences are not yet fully understood. This isotopic data has been gathered with a view to identifying hydrological problems in the region capable of study by isotopic methods and as essential background data to studies of the region's many hydrothermal systems. (auth.)

Deuterium dilution technique for body composition assessment: resolving methodological issues in children with moderate acute malnutrition

DEFF Research Database (Denmark)

Fabiansen, Christian; Yaméogo, Charles W; Devi, Sarita

2017-01-01

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...... quality when using the deuterium dilution technique in malnutrition studies in field conditions, and may encourage a wider use of isotope techniques....

Process for hydrogen isotope exchange and concentration between liquid water and hydrogen gas and catalyst assembly therefor

International Nuclear Information System (INIS)

Stevens, W.H.

1975-01-01

A bithermal, catalytic, hydrogen isotope exchange process between liquid water and hydrogen gas to effect concentration of the deuterium isotope of hydrogen is described. Liquid water and hydrogen gas are contacted with one another and with at least one catalytically active metal selected from Group VIII of the Periodic Table; the catalyst body has a water repellent, gas and water vapor permeable, organic polymer or resin coating, preferably a fluorinated olefin polymer or silicone resin coating, so that the isotope exchange takes place by two simultaneously occurring, and closely coupled in space, steps and concentration is effected by operating two interconnected sections containing catalyst at different temperatures. (U.S.)

Spin exchange in polarized deuterium

International Nuclear Information System (INIS)

Przewoski, B. von; Meyer, H.O.; Balewski, J.; Doskow, J.; Ibald, R.; Pollock, R.E.; Rinckel, T.; Wellinghausen, A.; Whitaker, T.J.; Daehnick, W.W.; Haeberli, W.; Schwartz, B.; Wise, T.; Lorentz, B.; Rathmann, F.; Pancella, P.V.; Saha, Swapan K.; Thoerngren-Engblom, P.

2003-01-01

We have measured the vector and tensor polarization of an atomic deuterium target as a function of the target density. The polarized deuterium was produced in an atomic beam source and injected into a storage cell. For this experiment, the atomic beam source was operated without rf transitions, in order to avoid complications from the unknown efficiency of these transitions. In this mode, the atomic beam is vector and tensor polarized and both polarizations can be measured simultaneously. We used a 1.2-cm-diam and 27-cm-long storage cell, which yielded an average target density between 3 and 9x10 11 at/cm 3 . We find that the tensor polarization decreases with increasing target density while the vector polarization remains constant. The data are in quantitative agreement with the calculated effect of spin exchange between deuterium atoms at low field

First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

International Nuclear Information System (INIS)

Shimada, Masashi; Hatano, Y.; Calderoni, P.; Oda, T.; Oya, Y.; Sokolov, M.; Zhang, K.; Cao, G.; Kolasinski, R.; Sharpe, J.P.

2011-01-01

With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 x 10 21 m -2 s -1 , ion fluence: 4 x 10 25 m -2 ) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

Science.gov (United States)

Shimada, Masashi; Hatano, Y.; Calderoni, P.; Oda, T.; Oya, Y.; Sokolov, M.; Zhang, K.; Cao, G.; Kolasinski, R.; Sharpe, J. P.

2011-08-01

With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 × 1021 m-2 s-1, ion fluence: 4 × 1025 m-2) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

Low-dose in vivo pharmacokinetic and deuterium isotope effect studies of N-nitrosodimethylamine in rats

International Nuclear Information System (INIS)

Mico, B.A.; Swagzdis, J.E.; Hu, H.S.; Keefer, L.K.; Oldfield, N.F.; Garland, W.A.

1985-01-01

The rates of elimination of N-nitrosodimethylamine (NDMA) and its fully deuterated analogue (N-nitrosodi[ 2 H6]methylamine, [ 2 H6]NDMA) were studied in vivo to explore the origins of the difference in their carcinogenicity. Male Fischer 344 rats, 7.5 weeks of age, were given nitrosamine bolus doses of 1.35 mumol/kg by tail vein injection and 2.02 or 4.05 mumol/kg by p.o. gavage. Animals were sacrificed at various time points from 2.5 to 180 min after i.v. administration or 5 to 120 min after p.o. dosage, and their blood was analyzed for NDMA by gas chromatography-high resolution mass spectrometry. After i.v. injection, blood nitrosamine concentrations declined in an apparently biexponential manner with a terminal half-life of 10 min for NDMA and 12 min for [ 2 H6]NDMA. The apparent total systemic blood clearances for NDMA and [ 2 H6]NDMA were 39 and 26 ml/min/kg, respectively. The apparent steady-state volumes of distribution were nearly identical (297 and 309 ml/kg, respectively). The areas under the curve after 2.02- and 4.05-mumol/kg p.o. doses were proportional to dose. The apparent bioavailability of NDMA was 8%, while that of [ 2 H6]NDMA was 21%. Isotope effects calculated as the ratios of first-pass metabolism, total systemic clearances, bioavailabilities, and intrinsic hepatic clearances were 1.2, 1.5, 2.6, and 3.2, respectively. The isotope effect determined from blood concentrations measured after simultaneous administration of NDMA and [ 2 H6]NDMA by steady-state infusion (each at 1.5 mumol/kg/h) was 2.6 +/- 0.9 (SD)

Deuterium isotope effects on the dipole moment and polarizability of HCl and NH3

International Nuclear Information System (INIS)

Scher, C.; Ravid, B.; Halevi, E.A.

1982-01-01

A previously described adaptation of the conventional Debye procedure for the direct determination of small dipole moment and polarizability differences between two polar gases is applied to the isotopic pairs DCl-HCl and ND 3 -NH 3 . The dipole moment difference obtained for the first isotopic pair, by using the Debye-Van Vleck equation for electric susceptibility, μ(DCl) - μ(HCl) = 0.005 5 +/- 0.0002 D, is consistent with published spectroscopically determined values of μ 00 (DCl) and μ 00 (HCl), while that obtained by using the classical Debye equation is not. For the second pair, use of the Debye-Van Vleck equation, along with a correction for thermal population of vibrationally excited levels, is shown to be essential and yields μ(ND) 3 - μ(NH 3 ) = +0.013 5 +/- 0.001 D and α(ND 3 ) - α(NH 3 ) = -(2.2 +/- 1.7) x 10 -26 cm 3

Chemical and environmental isotope study of precipitation in Syria

International Nuclear Information System (INIS)

Kattan, Z.

1999-01-01

Waters from a network of rainfall collection covering mine meteorological stations distributed mainly in the western part of Syria have been assayed using chemical and environmental isotope techniques for a period of 5 months from Dec. 1989 to Apr. 1990. The chemistry of rain waters falling over the mountainous stations shows a low solute concentration (20-105 mg 1 -1 ) compared with those falling over the coastal and anterior stations (50-210 mg 1 -1 ). The rain waters was generally characterized by a high deuterium excess (d=19%) compared with that of typical global meteoric waters (d=10%). The estimated deuterium excess is lower than that for the eastern Mediterranean meteoric waters (d=22%). The altitude effect is shown up by a depletion of heavy stable isotopes of about - 0.23% and -1.65% per 100 m elevation of δ 1 8 O and δD, respectively. The spatial distribution pattern of tritium contents shows a gradual build up with increasing distance from the Syrian coast. The weighted mean tritium content in rain waters falling over the country is estimated to amount to 9.5 tritium units (TU) during the period of observation. (author)

Experiments regarding organism behaviour under deuterium-depleted water influence

International Nuclear Information System (INIS)

Stefanescu, I.; Steflea, D.; Titescu, Gh.

1999-01-01

Deuterium-depleted water (DDW) is water that has an deuterium content D/(D+H) lower than 145 ppm. The role of naturally occurring D in living organisms was examined by using DDW instead of natural water. The DDW significantly decreased the growth rate of the L 929 fibroblast cell line and also inhibited the tumour growth. These suggest that the naturally occurring D has a central role in signal transduction involved in cell cycle regulation. Beginning with 1996, Institute of Cryogenics and Isotopic Separation, a DDW producer, co-operated with Romanian specialized institutes for evaluation of biological effects of DDW. These investigation lead to the following conclusions: 1. DDW caused a tendency of increasing the basal tone, accompanied by intensification of vasoconstrictor effects of phenylephrine, noradrenaline and angiotensin; the increase of the basal tone and vascular reactivity produced by DDW persists after removing the vascular in endothelium. 2. DDW stimulates immunodefence reactions, represented by the opsonic, bactericidal and phagocyte capacity of the immune system, together with increase in the number of polymorphonuclear neutrophils. 3. Animals treated with DDW showed an increase of the resistance both to the sublethal and to lethal gamma radiation doses, suggesting a radioprotective action. 4. Investigation regarding artificial reproduction of fish with DDW fecundated solutions confirmed favourable influence both in embryo growth stage and resistance in the following growing stages. 5. It was studied germination, growth and quantitative character variability of two genotypes of Avena Sativa; one can remark the favourable influence of DDW on biological process in plants in various ontogenetic stages. (authors)

Fine target of deuterium

International Nuclear Information System (INIS)

Diaz Diaz, J.; Granados Gonzalez, C. E.; Gutierrez Bernal, R.

1959-01-01

A fine target of deuterium on a tantalum plate by the absorption method is obtained. In order to obtain the de gasification temperature an induction generator of high frequency is used and the deuterium pass is regulated by means of a palladium valve. Two vacuum measures are available, one to measure the high vacuum in the de gasification process of the tantalum plate and the other, for low vacuum, to measure the deuterium inlet in the installation and the deuterium pressure change in the installation after the absorption in the tantalum plate. A target of 48 μ gr/cm 2 thick is obtained. (Author) 1 refs

Retention of Hydrogen Isotopes in Divertor Tiles Used in JT-60U

International Nuclear Information System (INIS)

Hirohata, Y.; Shibahara, T.; Tanabe, T.; Oya, Y.; Arai, T.; Gotoh, Y.; Masaki, K.; Yagyu, J.; Oyaidzu, M.; Okuno, K.; Nishikawa, M.; Miya, N.

2005-01-01

Retention characteristics of deuterium and hydrogen retained in graphite tiles placed in the divertor region of JT-60U were investigated by thermal desorption spectroscopy (TDS). The deuterium retained in the near surface of all graphite tiles was mostly replaced by hydrogen due to exposure to hydrogen plasma at the final stage operations, resulting in main deuterium retention in the deeper region. The dominant species desorbed from the divertor tiles were H 2 , HD, D 2 and CH 4 . The smallest retention of hydrogen isotopes (H+D) was observed in the outer divertor tile which was eroded with maximum of 20 μm depth. The amount of H+D retained in the inner divertor tiles covered by the re-deposited layers increased with the thickness of the re-deposited layers. Hydrogen isotopes concentration ((H+D)/C) in the re-deposited layers was ∼0.02, which was much smaller than those observed in JET and other devices

Hydrogen-water isotopic exchange process

International Nuclear Information System (INIS)

Cheung, H.

1983-01-01

Deuterium is concentrated in a hydrogen-water isotopic exchange process enhanced by the use of catalyst materials in cold and hot tower contacting zones. Water is employed in a closed liquid recirculation loop that includes the cold tower, in which deuterium is concentrated in the water, and the upper portion of the hot tower in which said deuterium is concentrated in the hydrogen stream. Feed water is fed to the lower portion of said hot tower for contact with the circulating hydrogen stream. The feed water does not contact the water in the closed loop. Catalyst employed in the cold tower and the upper portion of the hot tower, preferably higher quality material, is isolated from impurities in the feed water that contacts only the catalyst, preferably of lower quality, in the lower portion of the hot zone. The closed loop water passes from the cold zone to the dehumidification zone, and a portion of said water leaving the upper portion of the hot tower can be passed to the humidification zone and thereafter recycled to said closed loop. Deuterium concentration is enhanced in said catalytic hydrogen-water system while undue retarding of catalyst activity is avoided

Method to separate and enrich molecules containing deuterium

International Nuclear Information System (INIS)

Benson, S.W.

1978-01-01

Organic molecules having a normal H and D content and the general formula RX, in which R is chosen from ethyl, isopropyl, tert. butyl or cyclopentenyl groups and X is a functional group such as F, Cl, Br or OH and can even be H in the special case of cyclopentene, are exposed to an infra-red laser radiation. By careful adjustment, bundling and pulsing of an infrared laser, D-contained RX molecules exposed to the laserbeam, can dissociate or decompose. A D-contained olefin and HX is formed under suitable conditions after exposure to laser radiation. The D-contained olefin is drawn off and combusted to obtain D-contained water or D-contained hydrogen. The non-decomposed or non-reacted RX molecules which are deuterium-impoverished can be decomposed to deuterium impoverished olefins and HX in a further process step by heating on a catalyst. The latter products can then be separated off and be catylytically exchanged with normal water in order to reproduce the normal isotopic composition. They may then where necessary be catalytically recombined to form normal RX which can be recycled. (GG) [de

A Microdrop Generator for the Calibration of a Water Vapor Isotope Ratio Spectrometer

NARCIS (Netherlands)

Iannone, Rosario Q.; Romanini, Daniele; Kassi, Samir; Meijer, Harro A. J.; Kerstel, Erik R. Th.

A microdrop generator is described that produces water vapor with a known isotopic composition and volume mixing ratio for the calibration of a near-infrared diode laser water isotope ratio spectrometer. The spectrometer is designed to measure in situ the water vapor deuterium and oxygen ((17)O and

The isotope effect on divertor conditions and neutral pumping in horizontal divertor configurations in JET-ILW Ohmic plasmas

Directory of Open Access Journals (Sweden)

J. Uljanovs

2017-08-01

Full Text Available Understanding the impact of isotope mass and divertor configuration on the divertor conditions and neutral pressures is critical for predicting the performance of the ITER divertor in DT operation. To address this need, ohmically heated hydrogen and deuterium plasma experiments were conducted in JET with the ITER-like wall in varying divertor configurations. In this study, these plasmas are simulated with EDGE2D-EIRENE outfitted with a sub-divertor model, to predict the neutral pressures in the plenum with similar fashion to the experiments. EDGE2D-EIRENE predictions show that the increased isotope mass results in up to a 25% increase in peak electron densities and 15% increase in peak ion saturation current at the outer target in deuterium when compared to hydrogen for all horizontal divertor configurations. Indicating that a change from hydrogen to deuterium as main fuel decreases the neutral mean free path, leading to higher neutral density in the divertor. Consequently, this mechanism also leads to higher neutral pressures in the sub-divertor. The experimental data provided by the hydrogen and deuterium ohmic discharges shows that closer proximity of the outer strike point to the pumping plenum results in a higher neutral pressure in the sub-divertor. The diaphragm capacitance gauge pressure measurements show that a two to three-fold increase in sub-divertor pressure was achieved in the corner and nearby horizontal configurations compared to the far-horizontal configurations, likely due to ballistic transport (with respect to the plasma facing components of the neutrals into the sub-divertor. The corner divertor configuration also indicates that a neutral expansion occurs during detachment, resulting in a sub-divertor neutral density plateau as a function of upstream density at the outer-mid plane.

Hydrogen isotope permeation in elastomeric materials

International Nuclear Information System (INIS)

Steinmeyer, R.H.; Braun, J.D.

1976-01-01

The permeabilities of elastomeric and polymeric materials to hydrogen isotopes were measured at room temperature. The technique for measuring permeation rates is based on the following constant-volume method: a fixed pressure of gas is applied to one side of the specimen to be studied and the permeability constant is determined from the observed rate of pressure increase in an initially evacuated volume on the other side of the specimen. Permeability constants for hydrogen, deuterium, and tritium were measured for Mylar, Teflon, Kapton, Saran, Buna-N, and latex rubber. Results were compared with literature values for hydrogen and deuterium where available and showed excellent agreement

Synthesis of Melamine-d6 and the Feasibility of Deuterium Labeled Compounds as Internal Standard

Directory of Open Access Journals (Sweden)

GUO Yang-zhen

2015-11-01

Full Text Available S-triazine is an important chemical intermediate. Melamine belongs to s-triazine, which has been widely used as an additive in the food industry. To study the stable isotope labeling method of heterocyclic triazine compounds and its application, one step synthesis of melamine-d6 was achieved with a yield of 30% (calculate in ND4OD, which started from ND4OD by the reaction with cyanuric chloride. According to the exchange mechanism of H/D, the feasibility and the necessary conditions were discussed for applying deuterium labeled compounds in isotope dilution mass spectrometry method.

Isotopic effects in mechanistic studies of biotransformations of fluorine derivatives of L-alanine catalysed by L-alanine dehydrogenase

International Nuclear Information System (INIS)

Szymańska-Majchrzak, Jolanta; Pałka, Katarzyna; Kańska, Marianna

2017-01-01

Synthesis of 3-fluoro-[2- 2 H]-L-alanine (3-F-[ 2 H]-L-Ala) in reductive amination of 3-fluoropyruvic acid catalysed by L-alanine dehydrogenase (AlaDH) was described. Fluorine derivative was used to study oxidative deamination catalysed by AlaDH applied kinetic (for 3-F-L-Ala in H 2 O - KIE’s on V max : 1.1; on V max /K M : 1.2; for 3-F-L-Ala in 2 H 2 O – on V max : 1.4; on V max /K M : 2.1) and solvent isotope effect methods (for 3-F-L-Ala - SIE’s on V max : 1.0; on V max /K M : 0.87; for 3-F-[2- 2 H]-L-Ala – on V max : 1.4; on V max /K M : 1.5). Studies explain some details of reaction mechanism. - Highlights: • Synthesis of 3-fluoro-[2- 2 H]-L-alanine was performed. • The reactions were catalysed using the enzyme L-alanine dehydrogenase. • Performed reactions involved fluorinated analogues of L-alanine. • Solvent isotope effects of deuterium were determined. • Kinetic isotope effects were determined for obtained 3-fluoro-L-alanine. • The mechanism of reaction catalysed by L-alanine dehydrogenase was proposed.

Isotope effects in the evaporation of water: a status report of the Craig-Gordon model.

Science.gov (United States)

Horita, Juske; Rozanski, Kazimierz; Cohen, Shabtai

2008-03-01

The Craig-Gordon model (C-G model) [H. Craig, L.I. Gordon. Deuterium and oxygen 18 variations in the ocean and the marine atmosphere. In Stable Isotopes in Oceanographic Studies and Paleotemperatures, E. Tongiorgi (Ed.), pp. 9-130, Laboratorio di Geologia Nucleare, Pisa (1965).] has been synonymous with the isotope effects associated with the evaporation of water from surface waters, soils, and vegetations, which in turn constitutes a critical component of the global water cycle. On the occasion of the four decades of its successful applications to isotope geochemistry and hydrology, an attempt is made to: (a) examine its physical background within the framework of modern evaporation models, (b) evaluate our current knowledge of the environmental parameters of the C-G model, and (c) comment on a general strategy for the use of these parameters in field applications. Despite its simplistic representation of evaporation processes at the water-air interface, the C-G model appears to be adequate to provide the isotopic composition of the evaporation flux. This is largely due to its nature for representing isotopic compositions (a ratio of two fluxes of different isotopic water molecules) under the same environmental conditions. Among many environmental parameters that are included in the C-G model, accurate description and calculations are still problematic of the kinetic isotope effects that occur in a diffusion-dominated thin layer of air next to the water-air interface. In field applications, it is of importance to accurately evaluate several environmental parameters, particularly the relative humidity and isotopic compositions of the 'free-atmosphere', for a system under investigation over a given time-scale of interest (e.g., hourly to daily to seasonally). With a growing interest in the studies of water cycles of different spatial and temporal scales, including paleoclimate and water resource studies, the importance and utility of the C-G model is also likely to

Effects of trophic level and metamorphosis on discrimination of hydrogen isotopes in a plant-herbivore system

Science.gov (United States)

Peters, Jacob M.; Wolf, Nathan; Stricker, Craig A.; Collier, Timothy R.; Martinez del Rio, Carlos

2012-01-01

The use of stable isotopes in ecological studies requires that we know the magnitude of discrimination factors between consumer and element sources. The causes of variation in discrimination factors for carbon and nitrogen have been relatively well studied. In contrast, the discrimination factors for hydrogen have rarely been measured. We grew cabbage looper caterpillars (Trichoplusia ni) on cabbage (Brassica oleracea) plants irrigated with four treatments of deuterium-enriched water (δD = -131, -88, -48, and -2‰, respectively), allowing some of them to reach adulthood as moths. Tissue δD values of plants, caterpillars, and moths were linearly correlated with the isotopic composition of irrigation water. However, the slope of these relationships was less than 1, and hence, discrimination factors depended on the δD value of irrigation water. We hypothesize that this dependence is an artifact of growing plants in an environment with a common atmospheric δD value. Both caterpillars and moths were significantly enriched in deuterium relative to plants by ~45‰ and 23‰ respectively, but the moths had lower tissue to plant discrimination factors than did the caterpillars. If the trophic enrichment documented here is universal, δD values must be accounted for in geographic assignment studies. The isotopic value of carbon was transferred more or less faithfully across trophic levels, but δ15N values increased from plants to insects and we observed significant non-trophic 15N enrichment in the metamorphosis from larvae to adult.

Links between meteorological conditions and spatial/temporal variations in long-term isotope records from the Austrian precipitation network

International Nuclear Information System (INIS)

Kaiser, A.; Scheifinger, H.; Kralik, M.; Papesch, W.; Rank, D.; Stichler, W.

2002-01-01

The isotope records from the Austrian Network for Isotopes in Precipitation (ANIP) show significant but not uniform long-term trends. While the 10-year running means of some mountain stations exhibit a pronounced increase in δ 18 O of about 1 per mille since 1975, the change of δ 18 O at the valley stations is much lower. There are also differences in the time behaviour. The differences in the δ 18 O-values of sampling stations at similar altitudes can be explained by different origins of the air moisture (Atlantic or Mediterranean influence). Furthermore, a significant difference in the behaviour of the deuterium excess at neighbouring mountain and valley stations has been observed. There is a slight increase of the yearly mean of the deuterium excess with increasing altitude of the sampling station. But moreover, the seasonal pattern of the deuterium excess is quite different. While the valley stations exhibit the expected minimum in summer, the mountain stations show a distinct maximum between June and October. As a first step into a comprehensive analysis of the meteorological effects on the isotope patterns, the role of advection of different air masses is studied by trajectory statistics. Back trajectories, based on the three dimensional wind fields of the ECMWF model, are calculated for each hour within each precipitation event. Thus, the frequency of the origin of air masses and their contribution to the isotope patterns of the monthly precipitation samples are studied for two selected mountain stations north and south of the main ridge of the Alps. (author)

Deuterium trapping in tungsten

Science.gov (United States)

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

Deuterium trapping in tungsten

International Nuclear Information System (INIS)

Poon, M.

2004-01-01

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 D 2 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

Deuterium trapping in tungsten

Energy Technology Data Exchange (ETDEWEB)

Poon, M

2004-07-01

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 D{sub 2} 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

Advances in deuterium dioxide concentration measurement

Energy Technology Data Exchange (ETDEWEB)

Shon, Woojung [University of Science & Technology, Daejeon (Korea, Republic of); Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yim, Sung Paal, E-mail: nspyim@kaeri.re.kr [University of Science & Technology, Daejeon (Korea, Republic of); Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Lim; Park, Hyunmin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Kwang Rag; Chung, Hongsuk [University of Science & Technology, Daejeon (Korea, Republic of); Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Cheo Kyung [Handong Global University, Pohang (Korea, Republic of)

2016-11-01

Highlights: • Heavy water (D{sub 2}O) with a high purity level is necessary for nuclear fusion application. • D{sub 2}O purity is analyzed using Fourier Transform infrared (FT-IR) spectroscopy and newly introduced off-axis integrated cavity output spectroscopy (OA-ICOS). • OA-ICOS has advantages in terms of analysis of D{sub 2}O vapor. • OA-ICOS is expected that it can be used for accurate isotopic analyses in the future. - Abstract: The deuterium–tritium (D–T) reaction has been identified as the most efficient reaction for fusion devices. Deuterium can be obtained by heavy water electrolysis. Heavy water (D{sub 2}O) with a high purity level is necessary for nuclear fusion application. A D{sub 2}O isotopic analysis is thus very important. A system for a heavy water analysis was built and a newly designed isotopic analysis experiment was carried out. We tried to analyze the D{sub 2}O purity using Fourier Transform infrared (FT-IR) spectroscopy and newly introduced off-axis integrated cavity output spectroscopy (OA-ICOS). We found that the OA-ICOS based on measurement via laser absorption spectroscopy shows very high sensitivity. We ameliorated the sensitivity by an order of magnitude of more than 10{sup 3}–10{sup 5}. We could make the apparatus smaller by employing very tiny diode laser and fiber optics elements of a DFB (Distributed Feedback) type. Consequently, our device has advantages in terms of maintainability and mobility even in a radioactive environment. This new method could be used for an accurate isotopic analysis in the future.

Deuterium high pressure target

International Nuclear Information System (INIS)

Perevozchikov, V.V.; Yukhimchuk, A.A.; Vinogradov, Yu.I.

2001-01-01

The design of the deuterium high-pressure target is presented. The target having volume of 76 cm 3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

Deuterium- and tritium-labelled compounds. Applications in the life sciences

Energy Technology Data Exchange (ETDEWEB)

Atzrodt, Jens; Derdau, Volker [Isotope Chemistry and Metabolite Synthesis, Integrated Drug Discovery, Medicinal Chemistry, Frankfurt (Germany); Kerr, William J.; Reid, Marc [Department of Pure and Applied Chemistry, WestCHEM, University of Strathclyde, Glasgow (United Kingdom)

2018-02-12

Hydrogen isotopes are unique tools for identifying and understanding biological and chemical processes. Hydrogen isotope labelling allows for the traceless and direct incorporation of an additional mass or radioactive tag into an organic molecule with almost no changes in its chemical structure, physical properties, or biological activity. Using deuterium-labelled isotopologues to study the unique mass-spectrometric patterns generated from mixtures of biologically relevant molecules drastically simplifies analysis. Such methods are now providing unprecedented levels of insight in a wide and continuously growing range of applications in the life sciences and beyond. Tritium ({sup 3}H), in particular, has seen an increase in utilization, especially in pharmaceutical drug discovery. The efforts and costs associated with the synthesis of labelled compounds are more than compensated for by the enhanced molecular sensitivity during analysis and the high reliability of the data obtained. In this review, advances in the application of hydrogen isotopes in the life sciences are described. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

Energy Technology Data Exchange (ETDEWEB)

Shimada, Masashi, E-mail: Masashi.Shimada@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Hatano, Y. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Calderoni, P. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Oda, T. [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo 113-8656 (Japan); Oya, Y. [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka 422-8529 (Japan); Sokolov, M. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhang, K. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Cao, G. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI 53706 (United States); Kolasinski, R. [Hydrogen and Metallurgical Science Department, Sandia National Laboratories, Livermore, CA 94551 (United States); Sharpe, J.P. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

2011-08-01

With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 x 10{sup 21} m{sup -2} s{sup -1}, ion fluence: 4 x 10{sup 25} m{sup -2}) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

Convergent synthesis of a deuterium-labeled serine dipeptide lipid for analysis of biological samples.

Science.gov (United States)

Dietz, Christopher; Clark, Robert B; Nichols, Frank C; Smith, Michael B

2017-05-30

Bacterial serine dipeptide lipids are known to promote inflammatory processes and are detected in human tissues associated with periodontal disease or atherosclerosis. Accurate quantification of bacterial serine lipid, specifically lipid 654 [((S)-15-methyl-3-((13-methyltetradecanoyl)oxy)hexadecanoyl)glycyl-l-serine, (3S)-l-serine] isolated from Porphyromonas gingivalis, in biological samples requires the preparation of a stable isotope internal standard for sample supplementation and subsequent mass spectrometric analysis. This report describes the convergent synthesis of a deuterium-substituted serine dipeptide lipid, which is an isotopically labeled homologue that represents a dominant form of serine dipeptide lipid recovered in bacteria. Copyright © 2017 John Wiley & Sons, Ltd.

Study on influencing factors for hydrogen isotopic exchange

International Nuclear Information System (INIS)

Gu Mei; Liu Jun; Luo Yangming

2013-01-01

Background: Hydrogen-water catalytic exchange reaction offers an approach to hydrogen isotope separation, which can be applied in heavy water detritiation. Purpose: To optimize the operating condition for hydrogen-water catalytic exchange reaction, we analysed the influence of different factors on the transfer coefficient. Methods: In detail, the isotope exchange experiments of H-D system were carried out in a self-designed catalytic bed loaded with hydrophobic catalyst and hydrophilic packing with certain volume ratio. The experiments showed the changes of both the transfer coefficient and the pressure drop of column with the changing of the operational temperatures (29℃, 45℃, 60℃ and 75℃), the ratios of gas to liquid (0.58, 1.17, 2.65, 3.54) and the deuterium concentrations (5.05×10 -3 , 1.0144×10 -2 , 2.01×10 -2 ). Results: Results showed that 45℃ is the optimal temperature for operating. The transfer coefficient increases with the increasing of the ratio of gas to liquid in the ranges of 0.58 to 1.17 and 2.65 to 3.56, while decreases with the deuterium concentration increases from 5.05×10 -3 to 2.01×10 -2 . The pressure drop of column increases with increasing of gas flow rate. Conclusions: The experiment proves that the ratio of gas to liquid, the reaction temperature and the deuterium concentration are all important factors, which influence the transfer coefficient of deuterium obviously. The optimal operating condition for hydrogen-water catalytic exchange reaction are as follows: the temperature is 45℃, the ratio of gas to liquid is 3.56, and the deuterium concentration is 2.01×10 -2 . (authors)

Properties of thick GEM in low-pressure deuterium

International Nuclear Information System (INIS)

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

2014-01-01

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 241 Am 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 10 3 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

Properties of thick GEM in low-pressure deuterium

Science.gov (United States)

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.

Deuterium retention and desorption behavior in an advanced reduced-activation alloy

Energy Technology Data Exchange (ETDEWEB)

Noh, S.J., E-mail: sjnoh@dankook.ac.kr [Department of Applied Physics, Dankook University, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of); Kim, H.S.; Byeon, W.J.; Shin, H.W. [Department of Applied Physics, Dankook University, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of); Lee, Cheol Eui [Department of Physics, Korea University, Seoul 136-713 (Korea, Republic of); Lee, S.K. [Nuclear Fusion Development Division, Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

2017-07-15

We present the first experimental results of the deuterium retention and desorption behavior in an advanced reduced-activation alloy (ARAA) under development in Korea. For the in-situ measurement of desorbed gases from samples immediately after irradiation, a thermal desorption spectroscopy (TDS) system clustered with an inductively coupled plasma ion source has been built. Samples were and were not irradiated with helium ions at energies of 1.4, 3.5, and 5.0 keV and then continuously irradiated with 1.7-keV deuterium ions. TDS measurements were performed in situ immediately after deuterium irradiation and after exposure to air for one week. The amount of desorbed deuterium is the largest for the sample without helium irradiation from the TDS results measured in situ immediately after irradiation. Further, the amount of desorbed deuterium is significantly lowered when the helium energy is increased to 3.5 keV with no significant changes thereafter, indicating that the layer formed by implanted helium at near or deeper than the stopping range for 1.7-keV deuterium ions effectively acts as a barrier against deuterium diffusion into the depth. Because of the strong diffusivity of deuterium into the ambient atmosphere, the amounts of desorbed deuterium are greatly reduced for the samples without helium irradiation and with 1.4-keV helium irradiation after exposure to air for one week. In addition, our deuterium results for the ARAA are also compared with the results for F82H by other authors. - Highlights: •The first result of the deuterium retention and desorption in an ARAA is presented. •The ARAA was irradiated with helium and then continuously irradiated with deuterium. •TDS measurements were performed in situ immediately after deuterium irradiation. •TDS measurements were performed after exposure to air for one week. •The effects of helium irradiation and exposure to air were investigated.

Effect of periodic deuterium ion irradiation on deuterium retention and blistering in Tungsten

Directory of Open Access Journals (Sweden)

M. Oya

2017-08-01

Full Text Available The effect of periodic irradiation on Deuterium (D retention and blistering in Tungsten (W was investigated. W samples were exposed to D plasma at a fixed fluence while varying the irradiation cycle number (1-shot, 2-shots and 3-shots. Exposure energy and flux were ∼50eV and ∼1 ×1022 D m−2 s−1, respectively. Sample temperatures were 537K and 643K. At 573K, D retention and blister density decreased with increasing number of irradiation cycle. In contrast at 643K, D retention showed no dependence on number of irradiation cycle. Therefore, sample temperature during irradiation is an important parameter in comparing the results of continuous and periodic irradiation, especially in studies involving extremely-high-flux (>1024 D m−2 s−1 irradiation and fluence dependency of D retention.

The centenary of the discovery of isotopes

International Nuclear Information System (INIS)

Soulie, Edgar

2013-01-01

This article recalls works performed by different scientists (Marckwald and Keetman, Stromholm and Svedberg, Soddy, Thompson, Aston) which resulted in the observation and identification of the existence of isotopes. The author also recalls various works related to mechanisms of production of isotopes, the discovery of uranium fission and the principle of chain reaction. The author notably evokes French scientists involved in the development of mass spectroscopy and in the research and applications on isotopes within the CEA after the Second World War. A bibliography of article and books published by one of them, Etienne Roth, is provided. References deal with nuclear applications of chemical engineering (heavy water and its production, chemical processes in fission reactors, tritium extraction and enrichment), isotopic fractioning and physical-chemical processes, mass spectrometry and isotopic analysis, isotopic geochemistry (on 07;Earth, search for deuterium in moon rocks and their consequences), first dating and the Oklo phenomenon, radioactive dating, water and climate (isotopic hydrology, isotopes and hailstone formation, the atmosphere), and miscellaneous scientific fields (nuclear measurements and radioactivity, isotopic abundances and atomic weight, isotopic separation and use of steady isotopes)

Studies on the separation of hydrogen isotopes and spin isomers by gas chromatography

International Nuclear Information System (INIS)

Pushpa, K.K.; Annaji Rao, K.

2000-08-01

Separation and analysis of mixture of hydrogen isotopes has gained considerable importance because of various applications needing different isotopes in lasers, nuclear reactions and tracer or labelled compounds. In the literature gas chromatographic methods are reported using columns packed with partly dehydrated or thoroughly dehydrated alumina/molecular sieve stationary phase at 77 deg K with helium, neon and even hydrogen or deuterium as carrier gas. In the present study an attempt is made to compare the chromatographic behaviour of these two stationary phases using virgin and Fe doped form in partly dehydrated and thoroughly dehydrated state, using helium, neon, hydrogen and deuterium as carrier gas. The results of this study show that helium or neon carrier gas behave similarly broad peaks with some tailing. Sharp symmetric peaks are obtained with hydrogen or deuterium carrier gas. This is attributed to large hold up capacity for H 2 or D 2 at 77 deg K in these materials as compared to helium or neon. Spin isomers of H 2 or D 2 are separated on Fe free stationary phases, though ortho H 2 and HD are not resolved. Using a combination of Fe doped short column and plain alumina column, both maintained in dehydrated form, the effect of Fe doping on thermal equilibrium of ortho/para forms at 77 deg K is clearly demonstrated. (author)

Hydro-geochemical and isotopic composition of ground water in Helwan area

Directory of Open Access Journals (Sweden)

W.M. Salem

2015-12-01

The environmental stable isotopes oxygen and hydrogen (18O, and deuterium were studied and used to identify the sources of recharge. The studied ground waters are enriched in D and 18O and the isotopic features suggest that most of the ground water recharged indirectly after evaporation prior to infiltration from irrigation return water as well as the contribution from Nile water.

The influence of column temperature on the hydrogen isotopes separation performance of FDC

International Nuclear Information System (INIS)

Deng Xiaojun; Luo Deli; Qin Cheng; Yang Wan; Huang Guoqiang; Huang Zhiyong

2014-01-01

Frontal displacement chromatography (FDC) is a promising method for hydrogen isotopes separation with obvious advantages such as simple operation process, low tritium retention in system and easy to scale up, etc. We designed and constructed a FDC device using Pd-Al 2 O 3 as separation material in previous study, and the feasibility of FDC for hydrogen isotopes separation was confirmed. On the basis of the results, a series of experiments at different column temperatures were carried out to investigate the temperature influence to the separation performance, with the composition of (5 ± 0.1)% H 2 -(5 ± 0.1)% D 2 -(90 ± 0.1)% Ar of feed gas. Experiments were carried out at the temperature of 303K, 273K, 263K, 253K, 213K, at the gas flow rate of 15 mL (NTP)/min. The results indicated that lower temperature, higher enrichment factor while the feed gas composition and the gas flow rate are definite; lower temperature, shorter 'separation transition state', and then better separation efficiency. The deuterium enrichment factor became 65 from l.5 while the temperature decreased to 273K from 303K. It also showed that the deuterium recovery ratio and the deuterium abundance of product gas increases with the temperature decrease except for the case of 303K. At the temperature of 273K and below, the deuterium recovery ratio were all higher than 42%, deuterium abundance of product were all larger than 98%, and the maximum of deuterium abundance at 213K was 99.8%. (authors)

Nuclear effect study on nucleon structure functions, in comparison with antineutrino interactions on neon and deuterium

International Nuclear Information System (INIS)

Vallee, C.

1984-03-01

We have studied the nuclear effects on high energy antineutrino charged current interactions by comparing the data which were taken in the Bubble Chamber BEBC filled with Neon and Deuterium. On the one hand, the study of nuclear reinteractions gave us the possibility to estimate the formation time of hadrons. On the other hand, the comparison of structure functions does not show any significant difference between Neon and Deuterium. Though this result does not contradict the effects observed with charged leptons by the EMC and SLAC experiments, it is strongly incompatible with certain theoretical interpretations which implied a stronger effect in antineutrino interactions [fr

Radiation-related retrograde hydrogen isotope and K-Ar exchange in clay minerals

International Nuclear Information System (INIS)

Halter, C.; Pagel, M.; Sheppard, S.M.F.; Weber, F.; Clauer, N.

1987-01-01

Hydrogen and oxygen isotope studies have been widely applied to characterize the origin of fluids during ore-foaming processes. The primary isotope record, however, may be disturbed by retrograde exchange reactions, thus complicating the interpretation of the data. The susceptibility of minerals to retrograde isotope and chemical exchange is variable, reflecting differences in the mechanism and rate of isotope exchange. Results are presented on deuterium depletion, K/Ar ages and H 2 O + content of illites associated with uranium mineralization from the Athabasca basin (Canada). (author)

Design study of fuel circulating system using Pd-alloy membrane isotope separation method

International Nuclear Information System (INIS)

Naito, T.; Yamada, T.; Yamanaka, T.; Aizawa, T.; Kasahara, T.; Nishikawa, M.; Asami, N.

1980-01-01

Design study on the fuel circulating system (FCS) for a tokamak experimental fusion reactor (JXFR) has been carried out to establish the system concept, to plan the development program, and to evaluate the feasibility of diffusion system. The FCS consists of main vacuum system, fuel gas refiners, isotope separators, fuel feeders, and auxiliary systems. In the system design, Pd-alloy membrane permeation method is adopted for fuel refining and isotope separating. All impurities are effectively removed and hydrogen isotopes are sufficiently separated by Pd-alloy membrane. The isotope separation system consists of 1st (47 separators) and 2nd (46 separators) cascades for removing protium and separating deuterium, respectively. In the FCS, while cryogenic distillation method appears to be practicable, Pd-alloy membrane diffusion method is attractive for isotope separation and refining of fuel gas. The choice will have to be based on reliability, economic, and safety analyses

Process for the production of high purity deuterium

International Nuclear Information System (INIS)

Arrathoon, R.

1977-01-01

A process for the electrolysis of heavy water which results in the production of high purity deuterium without periodic replenishment of the electrolyte with additional deuterated compounds is defined. Electrolysis is effected through the use of an inexpensive cation-action permselective membrane which is essentially a solid polymer electrolyte and which is capable of automatically separating the evolved deuterium and oxygen gas. This cation-active permselective membrane does not introduce any intrinsic impurities or tritium contamination in the generated deuterium gas, does not require periodic revitalization with deuterated compounds or other chemical compounds, and is characterized by an unusually high electrical efficiency

Stable isotope hydrology. Deuterium and oxygen-18 in the water cycle

International Nuclear Information System (INIS)

Gat, J.R.; Gonfiantini, R.

1981-01-01

This monograph is mainly intended for hydrologists, hydrogeologists and geochemists who want to become acquainted, rapidly but in some detail, with the theoretical background of stable isotope fractionation in natural physico-chemical processes involving fresh water, with the isotopic differences actually encountered in natural waters and with their use for practical hydrological purposes. Throughout the monograph, and in particular in the last chapter, a series of examples are discussed, giving the results obtained with stable isotope techniques in current hydrological and hydrogeological investigations or, more generally, in water resources exploration and assessment. One chapter is also dedicated to the techniques for measuring D/H and 18 O/ 16 O ratios in water

Kinetic isotope effect studies on milk xanthine oxidase and on chicken liver xanthine dehydrogenase

International Nuclear Information System (INIS)

D'Ardenne, S.C.; Edmondson, D.E.

1990-01-01

The effect of isotopic substitution of the 8-H of xanthine (with 2 H and 3 H) on the rate of oxidation by bovine xanthine oxidase and by chicken xanthine dehydrogenase has been measured. V/K isotope effects were determined from competition experiments. No difference in H/T (V/K) values was observed between xanthine oxidase and xanthine dehydrogenase. Xanthine dehydrogenase exhibited a larger T/D (V/K) value than that observed for xanthine oxidase. Observed H/T (V/K) values for either enzyme are less than those H/T (V/K) values calculated with D/T (V/K) data. These discrepancies are suggested to arise from the presence of a rate-limiting step(s) prior to the irreversible C-H bond cleavage step in the mechanistic pathways of both enzymes. These kinetic complexities preclude examination of whether tunneling contributes to the reaction coordinate for the H-transfer step in each enzyme. No observable exchange of tritium with solvent is observed during the anaerobic incubation of [8- 3 H]xanthine with either enzyme, which suggests the reverse commitment to catalysis (C r ) is essentially zero. With the assumption of adherence to reduced mass relationships, the intrinsic deuterium isotope effect ( D k) for xanthine oxidation is calculated. By the use of these values and steady-state kinetic data, the minimal rate for the hydrogen-transfer step is calculated to be ∼75-fold faster than k cat for xanthine oxidase and ∼10-fold faster than k cat for xanthine dehydrogenase. Values calculated for each enzyme were found to be identical within experimental uncertainty

Liquid hydrogen and deuterium targets; Cibles a hydrogene et deuterium liquides

Energy Technology Data Exchange (ETDEWEB)

Bougon, M; Marquet, M; Prugne, P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1961-07-01

A description is given of 1) Atmospheric pressure target: liquid hydrogen, 400 mm thickness; thermal insulation: styrofoam; the hydrogen vapors are used to improve the target cooling; Mylar windows. 2) Vacuum target: 12 liter content: hydrogen or deuterium; liquid thickness 400 mm; thermal insulation is afforded by a vacuum vessel and a liquid nitrogen shield. Recovery and liquefaction of deuterium vapors are managed in the vacuum vessel which holds the target. The target emptying system is designed for operating in a few minutes. (author) [French] Description de: 1) Cible a pression atmospherique; hydrogene liquide, 400 mm d'epaisseur; l'isolement thermique: styrofoam; on utilise les vapeurs d'hydrogene pour ameliorer le refroidissement de la cible; hublots en Mylar. 2) Cible sous vide; contenance 12 litres; hydrogene ou deuterium; epaisseur du liquide 400 mm; l'isolement thermique est assure par une cuve a vide et un ecran d'azote liquide. Recuperation et liquefaction des vapeurs de deuterium sont effectuees dans la cuve a vide contenant la cible. Le systeme de vidange pour la cible est concu pour fonctionner en quelques minutes. (auteur)

Study of variations of stable isotopes in precipitation: case of Antananarivo

International Nuclear Information System (INIS)

Randrianarivola, M.

2014-01-01

The isotopic signature of precipitation is the input signal in any study of hydrological cycle. The scientific objective of this work is to better understand the isotopic variations in precipitation and identify their processes. We used the network of measurement GNIP (Global Network of Isotopes in Precipitation) in which data is acquired by the International Atomic Energy Agency through isotope hydrology laboratory at INSTN-Madagascar. Analyzes stable isotopes ( 18O and 2 H), were performed at a monthly time step. We were able to confirm the relative importance of different mechanisms governing the isotopic composition of precipitation. The spatial distribution of abundance ratios of Antananarivo rain is in fact dictated by the temperature which follow indirectly from the effects of altitude and seasonal variations. At the monthly scale, local meteoric water line δ 2 H versus δ 18 O shows the specificity of Antananarivo (deuterium excess of 17.5‰ ). Additionally, seasonal variations in precipitation is related to the temperature such that in summer (d=15‰) and winter (d=18‰) [fr

A study of chemical equilibrium of tri-component mixtures of hydrogen isotopes

International Nuclear Information System (INIS)

Cristescu, Ioana; Cristescu, I.; Peculea, M.

1998-01-01

In this paper we present a model for computing the equilibrium constants for chemical reactions between hydrogen's isotopes as function of temperature. The equilibrium constants were expressed with the aid of Gibbs potential and the partition function of the mixture. We assessed the partition function for hydrogen's isotopes having in view that some nuclei are fermions and other bosons. As results we plotted the values of equilibrium constants as function of temperature. Knowing these values we determined the deuterium distribution on species (for mixture H 2 -HD-D 2 ) as function of total deuterium concentration and the tritium distribution on species (for mixtures D 2 -DT-T 2 and H 2 -HT-T 2 ) as function of total tritium concentration. (authors)

Deuterium exchange reaction in a trickle bed packed with a mixture of hydrophobic catalyst and hydrophilic packings

Energy Technology Data Exchange (ETDEWEB)

Seungwoo Paek [KAERI (Korea, Republic of); Heui-Joo Choi; DO-Hee Ahn; Kwang-Rag Kim; Minsoo Lee; Sung-Paal Yim; Hongsuk Chung

2006-07-01

Full text of publication follows: The isotopic exchange reaction between hydrogen and water on the platinum supported catalysts provides a useful step for separating hydrogen isotopes such as deuterium and tritium. The CECE (Combined Electrolysis Catalytic Exchange) with a hydrophobic catalyst is a very effective method to remove small quantities of tritium from light or heavy waste water streams because of its high separation factor and mild operating conditions. The CECE column is composed of an electrolysis cell and a liquid phase catalytic exchange column. This paper deals with the experiments for the hydrogen isotopic exchange reaction in a trickle bed reactor packed with a hydrophobic catalyst in order to develop the catalytic column of the CECE. Hydrophobic Pt/SDBC catalyst which has been developed for the LPCE column of WTRF (Wolsong Tritium Removal Facility) was tested in a trickle bed reactor. The catalyst column was packed with a mixture of hydrophobic catalyst and hydrophilic packing (Dixon gauze ring) to improve liquid distribution and vapor/liquid transfer area. An experimental apparatus was built for the test of the catalyst at various temperatures and gas velocities. The catalyst was packed wet into the column and water was injected at the top through a liquid distributor and trickled through a catalyst mixture. Hydrogen gas passed up the column and deuterium was transferred to water stream flowing counter currently. The temperature of the column was controlled to maintain at 60 deg. C using water jackets around the reactor and equilibrator, a feed waster heater, and a circulation water heater. A metal bellows pump was used to circulate the hydrogen gas at the typical flow rate of 60 LPM.The reactor pressure was controlled to maintain at 135 kPa (abs) by a water column. Gas samples were drawn off from the top and bottom of the column. The difference in deuterium concentration between the inlet and outlet gas samples was analyzed using Gas

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

Science.gov (United States)

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.

Characterization of hollow cathode fall field strength measured by Doppler-free two-photon optogalvanic spectroscopy via Stark splitting of the 2S level of hydrogen and deuterium

Energy Technology Data Exchange (ETDEWEB)

Perez, C; De la Rosa, M I; Gruetzmacher, K, E-mail: concha@opt.uva.e [Universidad de Valladolid, Facultad de Ciencias, 47071 Valladolid (Spain)

2010-05-01

Doppler-free two-photon optogalvanic spectroscopy has been applied to measure the strong electric field strength and the cathode fall characteristics of hollow cathode discharges operated in hydrogen and deuterium via the Stark splitting of the 2S level of atomic hydrogen isotopes. In this paper we show similarities and differences in the tendencies of the cathode fall characteristics of hydrogen and deuterium in a wide range of identical discharge parameters.

Characterization of hollow cathode fall field strength measured by Doppler-free two-photon optogalvanic spectroscopy via Stark splitting of the 2S level of hydrogen and deuterium

International Nuclear Information System (INIS)

Perez, C; De la Rosa, M I; Gruetzmacher, K

2010-01-01

Doppler-free two-photon optogalvanic spectroscopy has been applied to measure the strong electric field strength and the cathode fall characteristics of hollow cathode discharges operated in hydrogen and deuterium via the Stark splitting of the 2S level of atomic hydrogen isotopes. In this paper we show similarities and differences in the tendencies of the cathode fall characteristics of hydrogen and deuterium in a wide range of identical discharge parameters.

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

International Nuclear Information System (INIS)

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

1989-01-01

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

Environmental isotope data no. 10: World survey of isotope concentration in precipitation (1988-1991). Report from a network

International Nuclear Information System (INIS)

1994-01-01

This is the tenth volume of the publication Environmental Isotope Data: World Survey of Isotope Concentration in Precipitation. This volume is primarily concerned with the concentration of the environmental isotopes (tritium, deuterium and oxygen-18) in monthly samples of precipitation taken by a global network of 169 stations in the period 1988 to 1991. Selected meteorological data, such as the amount of precipitation, mean water vapour pressure and surface air temperature, are also presented. Data before 1988 which were unavailable at the time of the earlier issues have also been included in the latter part of this volume as late reports. The data are being widely used in hydrological, hydrometeorological and climatological studies. 9 refs, 2 figs

Breast milk intake and infant growth: an isotopic approach

International Nuclear Information System (INIS)

Bilal, R.; Roohi, S.

2000-01-01

The milk intake of the exclusively breast fed infants was measured with the help of Deuterium dilution method, previously established in our laboratory. The growth of excessively breast fed infants was monitored for size months and correlated with the milk intake. For the measurement of milk intake, saliva of mothers and urine of the infants was collected at 1, 2, 3, 4, 5, 6, 13 and 14 days after giving an appropriate oral dose of deuterium oxide. For determining the Hydrogen Isotope ratio (D/H(, the samples wee prepared utilizing Zn shot method and subsequently analyzed on Isotope ratio Mass Spectrometer. The results showed that mean breast milk intake of infants measured with Deuterium dilution method was 801 +- 262 gms/day at 31.15+- 7.7 days of age (n=17). at the age of 3 months, the milk intake increased to 998+- 397 gms/day. The growth data collected over six month period for 21 infants showed that they fall below the 50 percentile of National Center for Health Statistics (NCHS) for weight and length. The data suggests that although majority of infants were exclusively breast fed and the intake values were well above normal range yet their growth was far from optimum. (author)

Comparative study of heavy and deuterium-depleted water on platelet aggregation

International Nuclear Information System (INIS)

Haulica, I.; Neagu, B.; Boisteanu, C.P.; Bild, W.; Mihaila, C.; Bajenariu, M.

2000-01-01

The effects of timed incubation of PRP (Platelet-Rich Plasma) with various concentrations of deuterium-depleted or deuterated water were tested. Aggregation curves were obtained under constant stirring at 20 deg.C and at 37 deg.C, using 5 - 10 μM ADP as aggregation trigger, using a Specord photo colorimeter. Incubation with 10 % deuterated water showed a significant decrease in the aggregation curves, an effect consistent with the data in the literature. Incubation with deuterium depleted water in the same conditions showed a marked increase in the aggregation curves, which suggests a powerful pro-aggregating effect of deuterium depleted water. (authors)

Stable isotope oxygen-18 and deuterium analysis in surface and groundwater of the Jequitibá Creek Basin, Sete Lagoas, MG

International Nuclear Information System (INIS)

Linhares, Giovanna Maria Gardini; Moreira, Rubens Martins; Pimenta, Rafael Colombo; Scarpelli, Raquel Pazzini; Santos, Elizangela Augusta dos

2017-01-01

Groundwater is an important source of public and industrial supplies, and inadequate exploitation of water reflects negatively on its quality and production of wells, especially when located in karstic aquifers. The study area includes the Maize and Sorghum National Research / Embrapa, located in the karst region of Sete Lagoas, within of the Jequitibá creek sub-basin, an affluent of the Velhas River. The evaluation of the content of stable isotopes of hydrogen ( 2 H), or deuterium, and oxygen ( 18 O) of surface waters (lagoons) and groundwater (production and monitoring wells) collected from the study area allowed to know directly the origin of these waters, active climatic processes and interactions between different aquifers and surface bodies, as possible mixtures of water from different sources. The collected samples were analyzed by isotopic ratio mass spectrometry, IRMS Advantege - Thermo Science, from the Center for the Development of Nuclear Technology (CDTN). The mean values found for δ 18 O and δ 2 H in the waters of the monitoring wells were -6.40‰ and -43.21‰, respectively. For the production wells, mean values for δ 18 O and δ 2 H of -5.87 ‰ and -40.09‰, respectively, were obtained. When compared to GMWL, the collected groundwater originates attributed to the precipitations. The lagoon waters had mean values for δ 18 O and δ 2 H of -3.73‰ and -30.08‰. The water collected in the crystalline fissured aquifer presented mean values δ 18 O and δ 2 H of -6.91‰ and -40.26 ‰ respectively, in its rockier portion, and -6.09‰ and -43.05‰. (author)

Hydrogen isotope exchange of organic compounds in dilute acid at elevated temperatures

International Nuclear Information System (INIS)

Werstiuk, N.H.

1987-01-01

Introduction of one or more deuterium (or tritium) atoms into organic molecules can be accomplished in many ways depending on the nature of the substrate and the extent and sterochemistry of deuteriation or tritiation required. Some of the common methods include acid- and base-catalyzed exchange of carbonyl compounds, metal hydride reductions, dissolving metal reductions, catalytic reduction of double bonds, chromatographic exchange, homogeneous and heterogeneous metal-catalyzed exchange, base-catalyzed exchange of carbon acids other than carbonyl compounds and acid-catalyzed exchange via electrophilic substitution. Only the latter three methods have been used for perdeuteriation of organic compounds. A very useful compendium of labeling methods with examples has been available to chemists for some time. Although metal-catalyzed exchange has been used extensively, the method suffers from some deficiencies: irreproducibility of catalyst surfaces, catalyst poisoning, side reactions such as coupling and hydrogenolysis of labile groups and low deuterium incorporation. Usually a number of cycles are required with fresh catalyst and fresh deuterium source to achieve substantial isotope incorporation. Acid-catalyzed exchange of aromatics and alkenes, strongly acidic media such as liquid DBr, concentrated DBr, acetic acid/stannic chloride, concentrated D 3 PO 4 , concentrated DC1, D 3 PO 4 /BF 3 SO 2 , 50-80% D 2 SO 4 and DFSO 4 /SbF 5 at moderate temperatures (<100 degrees) have been used to effect exchange. The methods are not particularly suitable for large scale deuteriations because of the cost and the fact that the recovery and upgrading of the diluted deuterium pool is difficult. This paper describes the hydrogen isotope exchange of a variety of organic compounds in dilute aqueous acid (0.1-0.5 M) at elevated temperatures (150-300 degrees)

Deuterium abundance, from ultraviolet to visible

International Nuclear Information System (INIS)

Hebrard, Guillaume

2000-01-01

In the frame of the standard Big Bang model, the primordial abundance of deuterium is the most sensitive to the baryonic density of the Universe. It was synthesized only during the primordial nucleosynthesis few minutes after the Big Bang and no other standard mechanism is able to produce any further significant amount. On the contrary, since deuterium is burned up within stars, its abundance D/H decreases along cosmic evolution. Thus, D/H measurements constrain Big Bang and galactic chemical evolution models. There are three samples of deuterium abundances: primordial, proto-solar and interstellar. Each of them is representative of a given epoch, respectively about 15 Gyrs past, 4.5 Gyrs past and present epoch. Although the evolution of the deuterium abundance seems to be qualitatively understood, the measurements show some dispersion. Present thesis works are linked to deuterium interstellar abundance measurements. Such measurements are classically obtained from spectroscopic observations of the hydrogen and deuterium Lyman series in absorption in the ultraviolet spectral range, using space observatories. Results presented here were obtained with the Hubble Space Telescope and FUSE, which has recently been launched. Simultaneously, a new way to observe deuterium has been proposed, in the visible spectral range from ground-based telescopes. This has led to the first detections and the identification of the deuterium Balmer series, in emission in HII regions, using CFHT and VLT telescopes. (author) [fr

Defect trapping of deuterium implanted in aluminium

International Nuclear Information System (INIS)

Kido, Y.; Kakeno, M.; Yamada, K.; Hioki, T.; Kawamoto, J.

1982-01-01

The behaviour of deuterium implanted in Al was studied by the D( 3 He,p) 4 He and the D(d,p)T nuclear reactions. Changes of the depth profiles of the deuterium after heat treatments indicated that the implanted deuterium was trapped by the defect produced during the deuterium implantation and the release probability of the trapped deuterium increased as the specimen temperature was raised. Assuming a thermal equilibrium locally in the region of high defect concentration, the trapping energy of deuterium in Al was determined to be 0.12eV. Since the release probability for the single crystal was considerably larger than that for the polycrystal specimens, the deuterium was considered to be strongly trapped in the grain boundaries. Distributions of displaced Al atoms and the recovery of the lattice damage by annealing were measured by the channelling technique. (author)

Variation in the isotopic content of precipitation with altitude

International Nuclear Information System (INIS)

Stowhas, L.; Silva, C.; Moser, H.; Stichler, W.

1975-03-01

Monthly precipitation and single storms have been collected during three years at 12 stations along a W-E profile in Chile, going from Juan Fernandez Islands to Valparaiso, Santiago and Infiernillo in the Andes, and analysed for their deuterium content. The deltaD values are correlated with the altitude of the station, the mean temperature - which also largely depends on the altitude - and the distance from the sea. The correlation parameters show however important variations from year to year and even more from month to month. For instance, in the stretch Santiago (520 m a.s.l.) - La Parva (2680 m) the mean isotopic gradient with altitude were: -1.84 deltaD per mil/100 m in 1970, -1.09 in 1971 and -2.0 in 1972. The low value observed in 1971 could be a consequence of the peculiar weather characteristics of this unusually dry year. In the stretch from the coast to Santiago the trend of the isotopic composition of precipitation is more complicated, because the so-called continental effect is superimposed to the altitude effect. The deuterium content variations have been also determined in snowpack profiles at La Parva station. The results show that snow melting occurs slowly at the bottom during the whole winter, at the expenses of the heat stored during summer in the soil. The melting of the surface snow layers only starts at the end of the winter and then proceeds very fast

Noncovalent Hydrogen Isotope Effects

Science.gov (United States)

Buchachenko, A. L.; Breslavskaya, N. N.

2018-02-01

Zero-point energies (ZPE) and isotope effects, induced by intermolecular, noncovalent vibrations, are computed and tested by experimental data. The ZPE differences of H- and D-complexes of water with hydrogen, methane, and water molecules are about 100-300 cal/mol; they result to isotope effects IE of 1.20-1.70. Semi-ionic bonds between metal ions and water ligands in M(H2O) 6 2+ complexes are much stronger; their ZPEs are about 12-14 kcal/mol per molecule and result to IE of 1.9-2.1 at 300 K. Protonated (deuterated) water and biwater exhibit the largest ZPE differences and isotope effects; the latter are 25-28 and 12-13 for water and biwater, respectively. Noncovalent IEs contribute markedly into the experimentally measured effects and explain many anomalous and even magic properties of the effects, such as the dependence of IE on the solvents and on the presence of the third substances, enormously large isotope effects at the mild conditions, the difference between IEs measured in the reactions of individual protiated and deuterated compounds and those measured in their mixture. Noncovalent IEs are not negligible and should be taken into account to make correct and substantiated conclusions on the reaction mechanisms. The kinetic equations are derived for the total isotope effects, which include noncovalent IEs as additive factors.

Deuterium trapping in liquid lithium irradiated by deuterium plasma

International Nuclear Information System (INIS)

Pisarev, A.; Moshkunov, K.; Vizgalov, I.; Gasparyan, Yu.

2013-01-01

Liquid lithium was irradiated by deuterium plasma to a low fluence of 10 22 –10 23 D/m 2 , cooled down to room temperature, and then slowly heated. The temperature and release rate were measured during heating. Two plateaus on the temperature–time dependence were observed at 180 °C and 660 °C. The first one corresponds to melting of Li and the second one – either to melting or to decomposition of solid LiD. Features of deuterium release in TDS were interpreted in terms of decomposition of lithium deuterides formed during plasma irradiation

Deuterium ion irradiation damage and deuterium trapping mechanism in candidate stainless steel material (JPCA2) for fusion reactor

International Nuclear Information System (INIS)

Ashizuka, Norihiro; Kurita, Takaaki; Yoshida, Naoaki; Fujiwara, Tadashi; Muroga, Takeo

1987-01-01

An improved austenitic stainless steel (JPCA), a candidate material for fusion reactor, is irradiated at room temperature with deuterium ion beams. Desorption spectra of deuterium gas is measured at various increased temperatures and defects formed under irradiation are observed by transmission electron microscopy to determine the mechanism of the thermal release of deuteriums and the characteristics of irradiation-induced defects involved in the process. In the deuterium deportion spectra observed, five release stages are found to exist at 90 deg C, 160 deg C, 220 deg C, 300 deg C and 400 deg C, referred to as Stage I, II, III, IV and V, respectively. Stage I is interpreted as representing the release of deuteriums trapped in point defects (presumably vacancies) formed under irradiation. The energy of desorption from the trapping sites is estimated at 0.8 eV. Stage II is concluded to be associated with the release of deuteriums trapped in a certain kind of existing defects. Stage III involves the release of deuteriums that are trapped in dislocations, dislocation loops or dislocated portions of stacking fault tetrahedra. This release occurs significantly in processed materials and other materials irradiated with high energy ion beams that may cause cascade damage. Stage IV is interpreted in terms of thermal decomposition of small deuterium clusters. Stage V is associated with the decomposition of rather large deuterium clusters grown on the {111} plane. (Nogami, K.)

The Effect of Ion Energy and Substrate Temperature on Deuterium Trapping in Tungsten

Science.gov (United States)

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

Determination of hydrogen isotope composition in organic compounds

International Nuclear Information System (INIS)

Ordzhonikidze, K.G.; Parulava, L.P.; Vakhaniya, G.V.; Tarielashvili, V.O.

1989-01-01

method for determination of hydrogen isotope composition just in organic compounds using mass-spectrometer of the second class is suggested. The method enables to determine atomic fraction of hydrogen without multiplet separation. The accuracy of determination of deuterium atomic fraction in acetone in 1-99% range was equal to 3-0.2% respectively

Thermal desorption spectroscopy for investigating hydrogen isotope behavior in materials

International Nuclear Information System (INIS)

Xia Tirui; Yang Hongguang; Zhan Qin; Han Zhibo; He Changshui

2012-01-01

The behavior of hydrogen isotope generated in fusion reactor materials is the key issue for safety and economic operation of fusion reactors and becomes an interesting field. In order to investigate the mechanism of hydrogen isotope such as diffusion, release and retention, a high-sensitivity thermal desorption spectroscopy (TDS) in combination with a quadruple mass spectrometer (QMS) was developed. A major technical breakthrough in ultrahigh vacuum (UHV), low hydrogen background, linear heating and sensitivity calibration of TDS system was made. UHV of l × 10 -7 Pa and low hydrogen background of l × 10 -9 Pa were obtained by combining turbo molecule pump and sputter ion pump. Specimens can be linearly heated up to 1173 K at the rate of 1 to 50 K/min under the MCGS PID software. Sensitivity calibration of the TDS system was accomplished using a special deuterium leak in the detector mode of QMS second electron multiplier. The desorption sensitivity coefficient and the minimum detection limit of deuterium desorption rate are 6.22 × l0 24 s -l · and l.24 × l0 -10 s -1 , respectively. The measurement was also routinely conducted on a specimen of standard, deuterium-containing Zr-4 alloy maintained in the laboratory, so as to validate the TDS method. (authors)

Method of producing deuterium-oxide-enriched water

International Nuclear Information System (INIS)

Mandel, H.

1976-01-01

A method and apparatus for producing deuterium-oxide-enriched water (e.g., as a source of deuterium-rich gas mixtures) are disclosed wherein the multiplicity of individual cooling cycles of a power plant are connected in replenishment cascade so that fresh feed water with a naturally occurring level of deuterium oxide is supplied to replace the vaporization losses, sludge losses and withdrawn portion of water in a first cooling cycle, the withdrawn water being fed as the feed water to the subsequent cooling cycle or stage and serving as the sole feed-water input to the latter. At the end of the replenishment-cascade system, the withdrawn water has a high concentration of deuterium oxide and may serve as a source of water for the production of heavy water or deuterium-enriched gas by conventional methods of removing deuterium oxide or deuterium from the deuterium-oxide-enriched water. Each cooling cycle may form part of a thermal or nuclear power plant in which a turbine is driven by part of the energy and air-cooling of the water takes place in the atmosphere, e.g., in a cooling tower

Precipitation, flood- and groundwaters of the Negev highlands. An isotopic study of desert hydrology

International Nuclear Information System (INIS)

Levin, M.; Issar, A.

1980-01-01

Precipitation in the Negev highlands was found to be surprisingly depleted of 18 O and deuterium and generally characterized by ''deuterium excess'' values of d>15per mille. Isotopic compositions are relatively uniform over a wide area on any particular day, but differ appreciably from storm to storm. Thus, they are valuable tools for hydrographic analysis of flood-flows. Flood-flow samples, collected in Nahal-Zin and Nahal-Besor, were often even more depleted in heavy isotopes than the total rainstorm, indicating that run-off is generated selectively by high-intensity rains. The initial rush of the flood flushed away the surface salinity and saline accumulations in surface pools, but apparently does not involve sub-surface salinity to any great extent. Recharge to groundwater appears to be accompanied by a slight evaporative enrichment of the isotopes, more so in the case of waters recharged from flood-flows. Environmental tritium can be used as an indicator of direct flood-water contributions to the aquifers. (author)

Experiments regarding organism's behaviour under deuterium-depleted water influence

International Nuclear Information System (INIS)

Stefanescu, I.; Steflea, D.; Titescu, Gh.

1999-01-01

Deuterium-depleted water (DDW) has an isotopic content smaller than 45 ppm D/(D+H). The role of naturally occurring D in living organisms was examined by using DDW instead of natural water. The DDW significantly decreased the growth rate of the L929 fibroblast cell line, and also inhibited the tumour growth. These suggest that the naturally occurring D has a central role in signal transduction involved in cell cycle regulation. Beginning with 1996 the Institute of Cryogenics and Isotope Separation, DDW producer, co-operated with Romanian specialised institutes for biological effect's evaluation of DDW. These investigations led to the following conclusions: - DDW caused a tendency of increasing the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tone and vascular reactivity produced by the DDW persists after the removal of the vascular endothelium. - DDW stimulates immune defence reactions, represented by the opsonic, bactericidal and phagocyte capacity of the immune system, together with increase in the numbers of polymorphonuclear neutrophils. - Animals treated with DDW showed an increase of the resistance both to sublethal and to lethal gamma radiation doses, suggesting a radioprotective action. - Investigation regarding artificial reproduction of fish with DDW fecundated solutions confirmed favourable influence both in embryo growth stage and in resistance in the following growth stages. - One has studied germination growth and quantitative character's variability at two genotypes of Avena Sativa; one can remark the favourable influence of DDW on biological process at plants in various ontogenic stages. (authors)

Deuterium in New Zealand rivers and streams

International Nuclear Information System (INIS)

Stewart, M.K.; Cox, M.A.; James, M.R.; Lyon, G.

1983-07-01

Over 750 deuterium measurements on rivers and streams in New Zealand are reported. Monthly samples were collected for periods of several years from a number of representative rivers. These show irregular storm-to-storm as well as seasonal deuterium variations. The seasonal variations range from as low as 1 per mille for lake-fed rivers to 8-10 per mille for rivers with large spring snow-melt contributions. Variations in mean annual ΔD values are believed to reflect changes in climatic variables; the present data will be used to compare with future changes. The bulk of the data are single samples; these show a geographic variation related to the altitude, latitude and climatic character of the catchments, with the highest deuterium contents (ΔD = -20 per mille) occurring in the far north, and lowest contents (-80 per mille) in the inland Otago region. Regression equations derived for the ΔD dependence on altitude (h) and latitude (l), are ΔD = -0.0169 h - 30.2 and westerly influence. Eastern climatic zones have lower deuterium contents because of rainout effects on the axial ranges. Contours of constant

Modeling of present and Eemian stable water isotopes in precipitation

DEFF Research Database (Denmark)

Sjolte, Jesper

The subject of this thesis is the modeling of the isotopic temperature proxies d18O, dD and deuterium excess in precipitation. Two modeling studies were carried out, one using the regional climate model, and one using a global climate model. In the regional study the model was run for the period ...... the modeled isotopes do not agree with ice core data. The discrepancy between the model output and the ice core data is attributed to the boundary conditions, where changes in ice sheets and vegetation have not been accounted for.......The subject of this thesis is the modeling of the isotopic temperature proxies d18O, dD and deuterium excess in precipitation. Two modeling studies were carried out, one using the regional climate model, and one using a global climate model. In the regional study the model was run for the period...... 1959 to 2001 using meteorological data and a domain including Greenland and the surrounding North Atlantic. The model was found to reproduce the observed seasonal variability of temperature and precipitation well. In comparison with ice core data from Greenland and observations from coastal stations...

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

International Nuclear Information System (INIS)

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

1988-01-01

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

The Austrian Network of Isotopes in Precipitation and Surface water: more than 50 years applications and interpretations of basic isotope-hydrological data for Central Europe

Science.gov (United States)

Wyhlidal, S.; Rank, D.; Kralik, M.

2017-12-01

Austria runs one of the longest-standing and most dense isotope precipitation collection networks worldwide, resulting in a unique isotope time series. Stable isotope variations in precipitation are a consequence of isotope effects accompanying each step of the water cycle. Therefore, stable isotope ratios of oxygen (18O/16O) and hydrogen (2H/1H) in precipitation provide important information about the origin and atmospheric transport of water vapour. The separation of a remote moisture source signals from local influences is thereby challenging. The amount of precipitation in Austria is highly influenced by the Alpine mountain range (400-3.000 mm/a). The amount of annual precipitation increases towards the mountain ranges. However, strong regional differences exist between the north and south of the Austrian Alps because the Alpine range functions as weather divide. The isotope time series of the stations of the Austrian precipitation network show significant but not uniform long-term trends. While the 10-year running mean of some mountain stations exhibit a highly significant increase in δ18O of about 1 ‰ since 1975, the change of δ18O at the valley stations is less pronounced. The increasing δ18O values can be correlated to an increase mean air temperature in the Alpine area and can be used as an additional indicator of climate change in this region. The differences in δ18O-values of sampling stations at similar altitudes can be explained by the origin of the air moisture. An Atlantic influence causes lower δ18O-values than sources from the Mediterranean. This can be explained by the different distances to the sea. Deuterium excess is a second-order isotopic parameter which is often interpreted as a tracer of the evaporation conditions of water vapor at the moisture source in terms of relative humidity, wind speed, and sea surface temperature, but can also be modified by local influences, such as below-cloud evaporation and equilibrium fractionation under

The effect of charge exchange with neutral deuterium on carbon emission in JET divertor plasmas

International Nuclear Information System (INIS)

Maggi, C.; Horton, L.; Summers, H.

1999-11-01

High density, low temperature divertor plasma operation in tokamaks results in large neutral deuterium concentrations in the divertor volume. In these conditions, low energy charge transfer reactions between neutral deuterium and the impurity ions can in principle enhance the impurity radiative losses and thus help to reduce the maximum heat load to the divertor target. A quantitative study of the effect of charge exchange on carbon emission is presented, applied to the JET divertor. Total and state selective effective charge exchange recombination rate coefficients were calculated in the collisional radiative picture. These coefficients were coupled to divertor and impurity transport models to study the effect of charge exchange on the measured carbon spectral emission in JET divertor discharges. The sensitivity of the effect of charge exchange to the assumptions in the impurity transport model was also investigated. A reassessment was made of fundamental charge exchange cross section data in support of this study. (author)

Stable isotope oxygen-18 and deuterium analysis in surface and groundwater of the Jequitibá Creek Basin, Sete Lagoas, MG

Energy Technology Data Exchange (ETDEWEB)

Linhares, Giovanna Maria Gardini; Moreira, Rubens Martins; Pimenta, Rafael Colombo; Scarpelli, Raquel Pazzini; Santos, Elizangela Augusta dos, E-mail: giovannagardini@gmail.com, E-mail: rubens@cdtn.br, E-mail: colombopimenta@gmail.com, E-mail: raquelscarpelli@gmail.com, E-mail: elizangela.augusta@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Groundwater is an important source of public and industrial supplies, and inadequate exploitation of water reflects negatively on its quality and production of wells, especially when located in karstic aquifers. The study area includes the Maize and Sorghum National Research / Embrapa, located in the karst region of Sete Lagoas, within of the Jequitibá creek sub-basin, an affluent of the Velhas River. The evaluation of the content of stable isotopes of hydrogen ({sup 2}H), or deuterium, and oxygen ({sup 18}O) of surface waters (lagoons) and groundwater (production and monitoring wells) collected from the study area allowed to know directly the origin of these waters, active climatic processes and interactions between different aquifers and surface bodies, as possible mixtures of water from different sources. The collected samples were analyzed by isotopic ratio mass spectrometry, IRMS Advantege - Thermo Science, from the Center for the Development of Nuclear Technology (CDTN). The mean values found for δ{sup 18}O and δ{sup 2}H in the waters of the monitoring wells were -6.40‰ and -43.21‰, respectively. For the production wells, mean values for δ{sup 18}O and δ{sup 2}H of -5.87 ‰ and -40.09‰, respectively, were obtained. When compared to GMWL, the collected groundwater originates attributed to the precipitations. The lagoon waters had mean values for δ{sup 18}O and δ{sup 2}H of -3.73‰ and -30.08‰. The water collected in the crystalline fissured aquifer presented mean values δ{sup 18}O and δ{sup 2}H of -6.91‰ and -40.26 ‰ respectively, in its rockier portion, and -6.09‰ and -43.05‰. (author)

Regioselective photoisomerizations of bridgehead substituted dibenzobarrelenes and benzonorbornadienes. The implication of excited-state secondary deuterium isotope effects of benzo-vinyl bridging

International Nuclear Information System (INIS)

Paquette, L.A.; Bay, E.

1982-01-01

Replacement of a bridgehead hydrogen by deuterium in substituted dibenzobarrelenes and benzonorbornadienes leads to k/sub H//k/sub D/ values of 1.11-1.27 (cyclopropyl substitution disfavored); these effects are opposite to those seen with other substitutents (except bromine) and demand that bridged radicals be formed reversibly or not at all. Since results demonstrate that the influence of bridgehead substitutents is clearly large, it is possible that pendant functional groups at each of the available sites exert their influence in a direct concerted manner. At least three intriguing studies now become worthy of immediate attention. In the first, benzonorbornadienes that are differently substituted at the bridgehead sites may serve as exceptionally sensitive probes of relative radical stabilization capabilities in the excited state. Direct competition experiments of this sort are unprecedented. Secondly, it becomes important to assess the relative controlling powers of bridgehead/aryl and bridgehead/vinyl substitutent combinations

The effect of Fe and C in modifying deuterium pickup in Zr-2.5Nb: a response surface analysis

International Nuclear Information System (INIS)

Ploc, R.A.

2001-03-01

A Response Surface Analysis of the effect of iron and carbon in Zr-2.5Nb-Fe/C drop-castings has shown that iron and carbon have at least a quadratic, synergistic relationship on oxidation and deuterium pickup. Tests were performed in the Halden test reactor and associated autoclave for 208 days at 598 K (325 o C). The synergism explains why pressure tube data have limited value when attempting to deduce the effect of impurity elements on pick up. Out- and in-reactor pick up were similar in trend and magnitude except for the in-reactor deuterium pickup, which was about one-quarter of that out-reactor. Minimum in-reactor deuterium ingress is predicted for 30 ppm (wt) carbon and approximately 1,100 ppm (wt) of iron. Out-reactor optimal values are similar but with slightly higher iron values. (author)

Lagrangian process attribution of isotopic variations in near-surface water vapour in a 30-year regional climate simulation over Europe

Science.gov (United States)

Dütsch, Marina; Pfahl, Stephan; Meyer, Miro; Wernli, Heini

2018-02-01

Stable water isotopes are naturally available tracers of moisture in the atmosphere. Due to isotopic fractionation, they record information about condensation and evaporation processes during the transport of air parcels, and therefore present a valuable means for studying the global water cycle. However, the meteorological processes driving isotopic variations are complex and not very well understood so far, in particular on short (hourly to daily) timescales. This study presents a Lagrangian method for attributing the isotopic composition of air parcels to meteorological processes, which provides new insight into the isotopic history of air parcels. It is based on the temporal evolution of the isotope ratios, the humidity, the temperature, and the location of the air parcels. Here these values are extracted along 7-day backward trajectories started every 6 hours from near the surface in a 30-year regional climate simulation over Europe with the isotope-enabled version of the model of the Consortium for Small-Scale Modelling (COSMOiso). The COSMOiso simulation has a horizontal resolution of 0.25° and is driven at the lateral boundaries by a T106 global climate simulation with the isotope-enabled version of the European Centre Hamburg model (ECHAMwiso). Both simulations are validated against measurements from the Global Network of Isotopes in Precipitation (GNIP), which shows that nesting COSMOiso within ECHAMwiso improves the representation of δ2H and deuterium excess in monthly accumulated precipitation. The method considers all isotopic changes that occur inside the COSMOiso model domain, which, on average, correspond to more than half of the mean and variability in both δ2H and deuterium excess at the air parcels' arrival points. Along every trajectory, the variations in the isotope values are quantitatively decomposed into eight process categories (evaporation from the ocean, evapotranspiration from land, mixing with moister air, mixing with drier air