Deuterium Oxygen Research Articles

Identification of groundwater hydrogeochemistry and the hydraulic connections of aquifers in a complex coal mine

It is important to understand the changes in the chemical composition and connectivity of each aquifer in the arid-semi-arid riverine mines under the driving force of coal mining and to establish a rapid identification of water sources in the riverine mines, which is important for the protection of groundwater resources and safe production in the study area. By analyzing the numerical characteristics of conventional elements, cluster analysis and the deuterium–oxygen and tritium isotopes of different aquifers, the groundwater chemical characteristics and hydraulic connections of each aquifer were determined. Three identification charts (Piper and Durov identification charts of conventional hydrochemical components and deuterium–tritium isotope identification charts) were established to enable the rapid identification of each aquifer water source. The results showed that the main recharge source of groundwater in the study area was atmospheric precipitation. There was a significant indigenous connection between the Quaternary aquifer and the Zhiluo Formation aquifer but a limited indigenous connection between the Zhiluo Formation aquifer and the Yan'an Formation aquifer, creating local groundwater systems that altered the local groundwater circulation patterns, driven by coal mining. Three identification charts were established to determine the water inrush sources and propose targeted solutions for water inrush from different aquifers in the Shendong mining area based on the differences in hydrochemical ion characteristics as well as deuterium–oxygen and tritium isotopes.

Unveiling the nitrogen transport and transformation in different karst aquifers media

Karst aquifers, a significant source of drinking water worldwide, are vulnerable to anthropogenic pollutants because of their special hydrogeological conditions. However, distinguishing the nitrogen transformation process is difficult owing to the heterogeneity of karst media. Therefore, the process of nitrogen transformation in different karst aquifer media remains poorly understood. In this study, multiple stable isotopic and physicochemical indicators are combined, the sources of water and nitrogen are analysed, and the degree of openness and redox conditions of different media are discussed to elucidate the nitrate sources and N transformation in groundwater with different degrees of openness. Water isotopes indicate local meteoric groundwater origin. However, different karst aquifer media have different degrees of openness, resulting in the highest deuterium–oxygen isotope values in surface water, followed by conduit water, fissure water, and isolated cave water. Based on the evidence from isotope and physicochemical indicators, different karst aquifer media have different redox processes. Isolated cave water environments were under anoxic conditions dominated by sulfate reduction reactions. Fissure water was under temporary anoxic or sub-anoxic conditions dominated by denitrification reactions. Conduit water and karst surface water were between micro-oxygen and oxidising conditions, and nitrification was the key process. This phenomenon was observed because the diversity of karst media produces different conservation conditions and openness. The nitrate isotope and Bayesian mixing model indicate that the main sources of nitrate in karst groundwater in the study area are mostly associated with manure and sewage wastes, and a few are from soil organic nitrogen, atmospheric deposition, and chemical fertilizer. This study helps identify the migration and transformation patterns and processes of nitrogen in different karst aquifer media, providing a scientific basis for the restoration and remediation of contaminated karst groundwater.

Charge transfer across C-H⋅⋅⋅O hydrogen bonds stabilizes oil droplets in water.

The hydrophobic–water interface plays a key role in biological interactions. However, both the hydrophobic–water interfacial molecular structure and the origin of the negative zeta potential of hydrophobic droplets in water are heavily contested. We report polarimetric vibrational sum-frequency scattering of the O–D and C-H stretch modes of 200-nanometer hexadecane oil droplets dispersed in water. An unusually broad spectral distribution (2550 to 2750 per centimeter) of interfacial water molecules that were not hydrogen bonded to other water molecules was observed, as well as a blue shift in the vibrational frequency of the interfacial hexadecane C-H stretch modes. Oil and water frequency shifts correlated with the negative electrostatic charge. Molecular dynamics simulations demonstrated that the unexpected strong charge-transfer interactions arose from interfacial C–H∙∙∙O hydrogen bonds.

Hydrogeochemical Characteristics and Formation of Low-Temperature Geothermal Waters in Mangbang-Longling Area of Western Yunnan, China

Numerous low-temperature geothermal waters are distributed extensively in Mangbang-Longling of western Yunnan in China, whose formation mechanism has not been completely investigated yet. This study focused on the hydrogeochemical evolution, reservoir temperature, and recharge origin of geothermal waters using hydrogeochemical and deuterium-oxygen (D-O) isotopic studies. The low-temperature geothermal waters were characterized by HCO3-Na type, while shallow cold spring was of the hydrochemical type of HCO3-Ca. The hydrogeochemical characteristics of low-temperature geothermal waters were mainly determined by the dissolution of silicate minerals based on the geological condition and correlations of major and minor ions. The reservoir temperatures of low-temperature geothermal waters ranged from 111°C to 126°C estimated by silica geothermometry and the silicon-enthalpy graphic method. Low-temperature geothermal waters circulated at the largest depth of 1794–2077 m where deep high-temperature geothermal waters were involved. The data points of δD and δ18O of the hot spring water samples in the study area show a linear right-up trend, indicating the δ18O reaction between the water and rock and a possible mixture of magmatic water from below. The low-temperature thermal waters were recharged by meteoric water at the elevation of 2362–3653 m calculated by δD values. Upwelling by heating energy, low-temperature geothermal waters were exposed as geothermal springs in the fault and fracture intersection and mixed by up to 72% shallow cold waters at surface. Based on acquired data, a conceptual model of the low-temperature geothermal waters in the Mangbang-Longling area was proposed for future exploitation.

Hydrogeochemical Characteristics and Conceptual Model of the Geothermal Waters in the Xianshuihe Fault Zone, Southwestern China.

Abundant geothermal waters have been reported in the Yalabamei, Zhonggu, Erdaoqiao, and Yulingong geothermal areas of the Xianshuihe Fault Zone of western Sichuan, southwestern China. This study focused on the hydrogeochemical evolution, reservoir temperature, and recharge origin of geothermal waters using hydrochemical and deuterium-oxygen (D-O) isotopic studies. Shallow geothermal waters represented by geothermal springs and shallow drilled water wells are divided into two hydrochemical groups: (1) the Ca–Na–HCO3 type in the Erdaoqiao area, and (2) Na–HCO3 in other areas. Deep geothermal waters represented by deep drilled wells are characterized by the Na–Cl–HCO3 type. The major ionic compositions of geothermal water are primarily determined by the water–rock interaction with silicate and carbonate minerals. The reservoir temperatures estimated by multi-geothermometries have a range of 63–150 °C for shallow geothermal water and of 190–210 °C for deep geothermal water, respectively. The δ18O and δD compositions indicated geothermal waters are recharged by meteoric water from the elevation of 2923–5162 m. Based on the aforementioned analyses above, a conceptual model was constructed for the geothermal system in the Xianshuihe fault zone.

High resolution stable oxygen deuterium diagrams of ice wedges of Batagay yedoma, north of Central Yakutia

The main aim of the study is to determine stable oxygen and hydrogen isotope composition of Late Pleistocene syngenetic ice wedges of Batagay yedoma and to obtain the detailed isotope diagrams. Reconstructed mean January palaeotemperature is lower than -51 °С than completely confirmed validity of earlier created palaeotemperature maps for the period 30-25 thousand years ago where Batagay section is located within isotherm of -48 °С.

Thermo-oxidation of carbon codeposits and particles release during laser ablation in an oxygen atmosphere and its extrapolation to ITER codeposits

In this paper the laser ablation of tokamak carbon codeposits in vacuum and different gases will be presented. A strong deuterium emission decrease has been observed from the third laser pulse at the same location, which suggests the annealing of a part of the remaining codeposit (up to 0.5–0.7μm) to temperatures of 400–600°C. In addition, at the third pulse in oxygen deuterium emission is close to the noise level, indicating its earlier elimination by thermo-oxidation from the remaining film on the laser spot. Moreover, the suppression of the redeposited film surrounding the laser impact has also been observed together with CO+ emission. Both observations indicate a fast reaction of the laser-activated oxygen molecules with the released hydrocarbon molecules and probably also with the hot, emitted dust particles. On the other hand, dust particles ejection has been analyzed by fast camera. Large particles with almost the initial deuterium concentration have been observed to be produced in the first laser pulse. Finally a brief future-work study with ITER metallic—W and Be—codeposits with a few % of trapped deuterium has been made. In that case the produced dust particles are expected to have part of the initial deuterium due to the large annealing temperatures required for its elimination. This deuterium concentration will probably be reduced during laser ablation in an oxygen atmosphere.

An overview of recent physics results from NSTX

The National Spherical Torus Experiment (NSTX) is currently being upgraded to operate at twice the toroidal field and plasma current (up to 1 T and 2 MA), with a second, more tangentially aimed neutral beam (NB) for current and rotation control, allowing for pulse lengths up to 5 s. Recent NSTX physics analyses have addressed topics that will allow NSTX-Upgrade to achieve the research goals critical to a Fusion Nuclear Science Facility. These include producing stable, 100% non-inductive operation in high-performance plasmas, assessing plasma–material interface (PMI) solutions to handle the high heat loads expected in the next-step devices and exploring the unique spherical torus (ST) parameter regimes to advance predictive capability. Non-inductive operation and current profile control in NSTX-U will be facilitated by co-axial helicity injection (CHI) as well as radio frequency (RF) and NB heating. CHI studies using NIMROD indicate that the reconnection process is consistent with the 2D Sweet–Parker theory. Full-wave AORSA simulations show that RF power losses in the scrape-off layer (SOL) increase significantly for both NSTX and NSTX-U when the launched waves propagate in the SOL. Toroidal Alfvén eigenmode avalanches and higher frequency Alfvén eigenmodes can affect NB-driven current through energy loss and redistribution of fast ions. The inclusion of rotation and kinetic resonances, which depend on collisionality, is necessary for predicting experimental stability thresholds of fast growing ideal wall and resistive wall modes. Neutral beams and neoclassical toroidal viscosity generated from applied 3D fields can be used as actuators to produce rotation profiles optimized for global stability. DEGAS-2 has been used to study the dependence of gas penetration on SOL temperatures and densities for the MGI system being implemented on the Upgrade for disruption mitigation. PMI studies have focused on the effect of ELMs and 3D fields on plasma detachment and heat flux handling. Simulations indicate that snowflake and impurity seeded radiative divertors are candidates for heat flux mitigation in NSTX-U. Studies of lithium evaporation on graphite surfaces indicate that lithium increases oxygen surface concentrations on graphite, and deuterium–oxygen affinity, which increases deuterium pumping and reduces recycling. In situ and test-stand experiments of lithiated graphite and molybdenum indicate temperature-enhanced sputtering, although that test-stand studies also show the potential for heat flux reduction through lithium vapour shielding. Non-linear gyro kinetic simulations have indicated that ion transport can be enhanced by a shear-flow instability, and that non-local effects are necessary to explain the observed rapid changes in plasma turbulence. Predictive simulations have shown agreement between a microtearing-based reduced transport model and the measured electron temperatures in a microtearing unstable regime. Two Alfvén eigenmode-driven fast ion transport models have been developed and successfully benchmarked against NSTX data. Upgrade construction is moving on schedule with initial physics research operation of NSTX-U planned for mid-2015.

Local order in fully deuterated liquid acetic acid as studied by neutron scattering. Complementarity to X-ray results

A structural investigation of fully deuterated liquid acetic acid (AAd4) was performed at 298K and atmospheric pressure by using neutron scattering. The recorded data are analyzed to yield the total structure factor SM(q), the molecular form factor F1(q), the distinct pair correlation function gL(r) and the second signature of H-bonding, i.e. the deuterium oxygen interaction. Neutron scattering data, as well as recent X-ray studies, clearly show that the local order of the liquid is largely described by the short-range crystal structure.

Water's wafer-thin surface

A combination of vibrational spectroscopy and molecular calculations reveals that only the surface layer of water at the interface with air has a distinctly different structure from the bulk liquid. See Letter p.192 Surface phenomena at the air–water interface are of vital importance in many situations, from oceanography to atmospheric and environmental chemistry. An unanswered question in the field is how thin is the interfacial region — or how soon do the properties of bulk liquid water reappear as the interface is crossed. Using spectroscopy to probe the 'free OD' vibrational mode of water molecules with an oxygen–deuterium bond protruding from the surface and theoretical modelling to interpret the results, Stiopkin et al. find that water molecules straddling the interface form hydrogen bonds that are only slightly weaker than those in bulk water. This suggests a remarkably rapid onset of bulk-phase behaviour, and an extremely short 'healing length' for the interface on crossing from the air into the water phase.

The Hemolymph of the Ascidian Styela plicata (Chordata-Tunicata) Contains Heparin inside Basophil-like Cells and a Unique Sulfated Galactoglucan in the Plasma

The hemolymph of ascidians (Chordata-Tunicata) contains different types of hemocytes embedded in a liquid plasma. In the present study, heparin and a sulfated heteropolysaccharide were purified from the hemolymph of the ascidian Styela plicata. The heteropolysaccharide occurs free in the plasma, is composed of glucose ( approximately 60%) and galactose ( approximately 40%), and is highly sulfated. Heparin, on the other hand, occurs in the hemocytes, and high performance liquid chromatography of the products formed by degradation with specific lyases revealed that it is composed mainly by the disaccharides DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4)) (39.7%) and DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(6SO(4)) (38.2%). Small amounts of the 3-O-sulfated disaccharides DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(3SO(4)) (9.8%) and DeltaUA(2SO(4))-1-->4-beta-d-GlcN(SO(4))(3SO(4))(6SO(4)) (3.8%) were also detected. These 3-O-sulfated disaccharides were demonstrated to be essential for the binding of the hemocyte heparin to antithrombin III. Electron microscopy techniques were used to characterize the ultrastructure of the hemocytes and to localize heparin and histamine in these cells. At least five cell types were recognized and classified as univacuolated and multivacuolated cells, amebocytes, hemoblasts, and granulocytes. Immunocytochemistry showed that heparin and histamine co-localize in intracellular granules of only one type of hemocyte, the granulocyte. These results show for the first time that in ascidians, a sulfated galactoglucan circulates free in the plasma, and heparin occurs as an intracellular product of a circulating basophil-like cell.

Chemistry and isotopic composition of fumarole discharges of Furnas caldera

Two fumarole grounds at Lagoa das Furnas and Furnas village and a fumarole on the bank of Ribeira dos Tambores are located on a west–east tectonic lineament across the topographic low of the Furnas caldera. The discharge of the fumaroles derives from steam separation from shallow (100–200 m) aquifers at temperatures of about 180°C. As inferred from nitrogen/argon relations and deuterium–oxygen isotope relations the hydrothermal fluid is derived from local precipitation after some 10% steam fractionation in the fumarole conduits. Sulphur isotope ratios of the discharge, being close to those of juvenile rock sulphur, indicate extensive rock-leaching within the aquifers. The carbon isotope composition of the fumarole discharge and carbon dioxide saturated waters encountered across the caldera floor suggests that the source of carbon is regional outgassing of mantle derived juvenile carbon dioxide. Chemistry of the acid gases, carbon dioxide and hydrogen sulphide in the discharge indicates a slight fractionation induced by different boiling in the shallow hydrothermal aquifers. Traces of hydrogen and methane contained in the discharge bear no relation to the low temperature water–steam equilibria of the Furnas fumaroles. Assuming a deeper origin of these gases, a simple model for binary mixtures of methane and hydrogen indicates that these gases are derived from supercritical conditions, presumably equilibrated within hot rocks below the hydrothermal system. The remarkably stable ratios of hydrogen and methane, also considering their inferred deep origin, suggest that these gases might be considered for future chemical monitoring of the fumarole discharge in Furnas.

Use of molecular dynamics simulations with ab initio SCF calculations for the determination of the deuterium quadrupole coupling constant in liquid water and bond lengths in ice

AbstractThe deuterium quadrupole coupling constant and asymmetry parameter in heavy water were determined using ab initio SCF calculations. Snapshots from a molecular dynamics simulation were used to give liquid water cluster configurations and the influence of simulation parameters on the quadrupole coupling constant was investigated. The electronic potential model and the number of molecules in the molecular dynamics simulation and the pressure of the system were found to have only a small influence on the quadrupole coupling constant. The average value of the quadrupole coupling constant at room temperature, corrected for the known deficiency of the ab initio calculation in the gas phase, yields a quadrupole coupling constant of 253 kHz, in perfect agreement with the most recent experiments. The oxygen—deuterium bond lengths in ice Ih, ice II, and ice IX were determined using experimental quadrupole coupling constants and a model equation. An averaged bond length of 98.9 pm was obtained for the Ih form, which is approximately 2 pm shorter than that determined by neutron diffraction studies, whereas the bond lengths for the four deuterium sites in ice II and the three sites in ice IX are in fair agreement with experiment. © John Wiley & Sons, Inc.

Isotope effects on the combustion properties of deuterium and hydrogen

Some of the important combustion properties of deuterium such as flammability limits, laminar burning velocities, and detonation cell widths have been determined experimentally. The experiments provide a basis for evaluating the properties of deuterium-air or deuteriumoxygendiluent mixtures from the known combustion properties of hydrogen, using simple correlations.

Influence of a very low density of defects on the deuterium—oxygen reaction on Pt(111)

It is shown that defects created on a Pt(111) surface by a mild oxygen treatment or by argon-ion bombardment are very efficient in catalyzing the deuterium—oxygen reaction. We suggest that the same defects are also catalyzing the reaction on Pt(111) surfaces considered at present to be “ideal”. Previously reported experimental results can be explained, at least qualitatively, with this reaction model.

The deuterium—oxygen reaction on Pt(111): Influence of atomic steps

We have investigated the deuterium—oxygen reaction on a Pt(111) surface, and the influence of atomic steps on this reaction at surface temperatures around 500 K and oxygen coverages Θ O >0.01. The kinetics of the reaction has been studied with molecular beam relaxation spectroscopy (MBRS), while the surface has been characterized with respect to oxygen coverage and step density by thermal energy atom scattering (TEAS). It appears that the reaction becomes slower in the presence of steps. This is explained by hydroxyl (OD) or deuterium becoming non-reactive when bound at step sites. A model, assuming a fast equilibrium between deuterium bound at step and terrace sites, describes the measurements remarkably well. From the measurements, we derive a value of 4.8 kcal/mol for the difference in binding energy of deuterium at step and terrace sites, in good agreement with previously reported values.

Numerical investigation of a purely chemical generator of atomic gaseous hydrogen (deuterium) and of a cw H(D)–O3–CO2laser utilizing this generator

A numerical investigation is reported of a generator of atomic gaseous hydrogen (or deuterium) and of a cw low-toxicity H(D)–O3–CO2 laser utilizing this generator. A high nonequilibrium concentration of H (D) atoms is achieved in a supersonic oxygen–hydrogen (or oxygen–deuterium) flame in this generator. Hydrogen (deuterium) combustion regimes convenient for experimental realization and characterized by a molar concentration of atomic hydrogen (deuterium) in the flame by up to ~15%, are identified. Numerical optimization of all the components of a cw laser system in respect of the principal parameters is used to show that a cw D–O3–CO2 laser utilizing this chemical generator of deuterium atoms can have high output characteristics: a specific output power of ~140 W·sec·g−1, a chemical efficiency of ~10%, and an inversion zone of over 30 cm length in the downstream direction.

Isotopic identification of gases of a deep origin in French thermomineral waters

Within the subsurface convective system which constitutes the thermomineral waters of which the meteoric origin is proved by the oxygen—deuterium couple, the associated gases, free or dissolved, may represent the only “juvenile” component in this cycle. The “juvenile” origin of the gases can be clearly established through ascertaining the isotopic composition of certain elements: argon, nitrogen, carbon and helium. The study of these gases associated with thermomineral waters has been undertaken systematically since 1976. One of the first objectives of these investigations has been the determination of the carbon isotopic compositions of the carbon dioxide—bicarbonate system for ∼50 thermomineral springs in various geological settings: the Massif Central, Pyrénées, and Vosges mountainous regions, France. On the basis of isotopic compositions, three sources of primordial or initial carbon have been put forward which correspond to characteristic figures for the carbon compositions expressed in δ 13C-values. The exogenous carbon domain (δ 13C CO 2 from −10 to −25‰, δ 13C HCO − 3 from −18 to −2‰), the endogenous magmatic carbon domain (δ 13C CO 2 from −10 to −2‰, δ 13C HCO − 3 from −2 to +6‰) and the endogenous sedimentary carbon domain (δ 13C CO 2 from −2 to +2‰ and δ 13 C HCO − 3 〉 + 6‰ ). In the case of springs with exogenous carbon of which a part is atmospheric, nitrogen isotopes confirm that origin. In the cases of springs with magmatic or mantle carbon, argon isotopes indicate also a deep origin.