Science.gov

Sample records for metal sulphate hydrates

  1. Time-development of sulphate hydration in anhydritic swelling rocks

    NASA Astrophysics Data System (ADS)

    Serafeimidis, Konstantinos

    2015-04-01

    Anhydritic claystones are among the most problematic rocks in tunnelling due to their distinctive swelling properties. They consist of a clay matrix with distributed anhydrite particles, veins and layers and have caused severe damage to numerous tunnels excavated in the Gypsum Keuper formation in North-Western Switzerland and South-Western Germany. The swelling of anhydritic claystones which is mainly attributed to the transformation of anhydrite into gypsum (a chemical process which leads to an increase in the solids of 61 percent), is a markedly time-dependent process. It may take several decades to complete in nature and is therefore important for the design particularly of the final tunnel lining. Anhydrite occurs either in the form of particles or of layers and veins of different thicknesses and spacings. The particles may have an approximately spherical or rather prismatic form, while their size lies within a wide range (from few micrometer to few centimeter). The shape and size of the anhydrite particles and layers are important for the specific surface of anhydrite and thus for the evolution of its hydration over time. In the present contribution we focus on the kinetics of the chemical reactions in sulphatic rocks, limiting ourselves to closed systems, i.e. without investigating the effects of seepage flow and diffusive transport, which may also be important. In order to achieve this, a consistent and comprehensive dissolution and precipitation model has been developed that accounts for arbitrary geometrical forms of anhydrite as well as for the sealing of anhydrite by a layer of gypsum. The investigations have shown that anhydrite dissolution represents the limiting mechanism if anhydrite occurs in the form of larger particles or thicker veins (> 1 millimeter) and there are sufficient nuclei for gypsum growth (e.g. precipitation takes place on of the surfaces of inert minerals). It has also been indicated that the time required for the whole amount of

  2. Enhanced hydration of dipalmitoylphosphatidylcholine multibilayer by vinblastine sulphate.

    PubMed

    Ter-Minassian-Saraga, L; Madelmont, G

    1983-03-01

    Vinblastine sulphate, an antimitotic and anti-inflammatory agent, modifies the thermal behaviour of the model membranes: the dipalmitoylphosphatidylcholine DPPC bilayers. The mixed DPPC and vinblastine sulphate multibilayers in the range of DPPC mole fraction 0.4 to 1 display clearly the gel-liquid crystal (chain melting) transition on the thermograms obtained with a differential scanning microcalorimeter. The molar enthalpy of this transition is slightly depressed by vinblastine sulphate (less than 10%). The temperature-composition phase diagram corresponds to a total insolubility of vinblastine sulphate inside the frozen (gel) bilayers and to a solubility of 0.2 (mole fraction) of vinblastine sulphate inside the fluid (liquid crystalline) bilayers. The dissolved vinblastine sulphate depresses the cooperativity number of the frozen in equilibrium fluid transition of the bilayers very strongly (4- to 5-times). Up to its solubility concentration, vinblastine sulphate increases the amount of the structural water of the bilayers and modifies the thermal behaviour of this water. The 'expelled' vinblastine sulphate molecules are retained by the polar groups of DPPC molecules and screen their electrostatic interactions with the structural water molecules. Below 0 degree C, the amount of the structural water, which forms the aqueous separation between two bilayers, is enhanced by vinblastine sulphate. However, the drug reduces (screens) the bilayers interaction with the structural water molecules.

  3. Hydrated metal ions in the gas phase.

    PubMed

    Beyer, Martin K

    2007-01-01

    Studying metal ion solvation, especially hydration, in the gas phase has developed into a field that is dominated by a tight interaction between experiment and theory. Since the studied species carry charge, mass spectrometry is an indispensable tool in all experiments. Whereas gas-phase coordination chemistry and reactions of bare metal ions are reasonably well understood, systems containing a larger number of solvent molecules are still difficult to understand. This review focuses on the rich chemistry of hydrated metal ions in the gas phase, covering coordination chemistry, charge separation in multiply charged systems, as well as intracluster and ion-molecule reactions. Key ideas of metal ion solvation in the gas phase are illustrated with rare-gas solvated metal ions.

  4. Magnetic Properties of Sediments from IODP Expedition 311 - Cascadia Margin Gas Hydrates: Records of Fossil Sulphate Methane Interface?

    NASA Astrophysics Data System (ADS)

    Enkin, R. J.; Baker, J.; Esteban, L.; Mullin, A. J.; Paterson, B.; Hamilton, T. S.; Michael, R.

    2006-12-01

    interpret type-B samples to hold iron sulphides produced diagenetically from iron oxides within the sediments at the sulphate-methane interface. We hypothesize that the two magnetic behaviors record a stratigraphic and geochemical interplay between the sedimentation rate and changes in methane flux, sulphate reduction and the gas hydrate stability field with time.

  5. Metal halogen battery system with multiple outlet nozzle for hydrate

    DOEpatents

    Bjorkman, Jr., Harry K.

    1983-06-21

    A metal halogen battery system, including at least one cell having a positive electrode and a negative electrode contacted by aqueous electrolyte containing the material of said metal and halogen, store means whereby halogen hydrate is formed and stored as part of an aqueous material, means for circulating electrolyte through the cell and to the store means, and conduit means for transmitting halogen gas formed in the cell to a hydrate former whereby the hydrate is formed in association with the store means, said store means being constructed in the form of a container which includes a filter means, said filter means being inoperative to separate the hydrate formed from the electrolyte, said system having, a hydrate former pump means associated with the store means and being operative to intermix halogen gas with aqueous electrolyte to form halogen hydrate, said hydrate former means including, multiple outlet nozzle means connected with the outlet side of said pump means and being operative to minimize plugging, said nozzle means being comprised of at least one divider means which is generally perpendicular to the rotational axes of gears within the pump means, said divider means acting to divide the flow from the pump means into multiple outlet flow paths.

  6. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  7. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  8. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  9. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  10. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  11. Growth and spectral characterization of ethylene diamine tetra acetic acid (EDTA) doped zinc sulphate hepta hydrate - a semi organic NLO material.

    PubMed

    Ramachandra Raja, C; Ramamurthi, K; Manimekalai, R

    2012-12-01

    Semi-organic non-linear optical single crystals of ethylene diamine tetra acetic acid (EDTA) doped zinc sulphate hepta hydrate crystals were grown by slow evaporation solution growth technique, at room temperature, using de-ionized water as solvent. The modes of vibrations of different molecular groups present in the grown crystal were identified by FT-IR technique. The optical absorbance/transmittance was recorded in the wavelength range of 190-1100 nm. Thermal properties of the grown crystal were studied by thermo gravimetric analysis and differential thermal analysis. The melting point of the grown crystal was estimated by differential scanning calorimetric analysis. The inclusion of the dopant (EDTA) was confirmed by colorimetric estimation method. The second harmonic generation efficiency is about 30% of potassium dihydrogen orthophosphate.

  12. Hydrate-based heavy metal separation from aqueous solution

    NASA Astrophysics Data System (ADS)

    Song, Yongchen; Dong, Hongsheng; Yang, Lei; Yang, Mingjun; Li, Yanghui; Ling, Zheng; Zhao, Jiafei

    2016-02-01

    A novel hydrate-based method is proposed for separating heavy metal ions from aqueous solution. We report the first batch of experiments and removal characteristics in this paper, the effectiveness and feasibility of which are verified by Raman spectroscopy analysis and cross-experiment. 88.01-90.82% of removal efficiencies for Cr3+, Cu2+, Ni2+, and Zn2+ were obtained. Further study showed that higher R141b-effluent volume ratio contributed to higher enrichment factor and yield of dissociated water, while lower R141b-effluent volume ratio resulted in higher removal efficiency. This study provides insights into low-energy, intensive treatment of wastewater.

  13. Acid sulphate soil disturbance and metals in groundwater: implications for human exposure through home grown produce.

    PubMed

    Hinwood, Andrea Lee; Horwitz, Pierre; Appleyard, Steve; Barton, Caroline; Wajrak, Magda

    2006-09-01

    A significant emerging environmental problem is the disturbance and oxidation of soils with high levels of iron sulphide minerals resulting in acidification and causing the mobilization of metals into groundwater. This process is occurring in many parts of the world. In Western Australia, impacted groundwater is extracted by residents for domestic use. We sought to establish domestic use patterns of bore water and the concentration of metals. Sixty-seven domestic bore water samples clearly indicated oxidation of sulphidic materials with heavy metal concentrations ranging for aluminium (metals via the consumption of home grown produce. This warrants further investigation in light of increasing acid sulphate soil disturbance in many locations.

  14. Hydrate-based heavy metal separation from aqueous solution

    PubMed Central

    Song, Yongchen; Dong, Hongsheng; Yang, Lei; Yang, Mingjun; Li, Yanghui; Ling, Zheng; Zhao, Jiafei

    2016-01-01

    A novel hydrate-based method is proposed for separating heavy metal ions from aqueous solution. We report the first batch of experiments and removal characteristics in this paper, the effectiveness and feasibility of which are verified by Raman spectroscopy analysis and cross-experiment. 88.01–90.82% of removal efficiencies for Cr3+, Cu2+, Ni2+, and Zn2+ were obtained. Further study showed that higher R141b–effluent volume ratio contributed to higher enrichment factor and yield of dissociated water, while lower R141b–effluent volume ratio resulted in higher removal efficiency. This study provides insights into low-energy, intensive treatment of wastewater. PMID:26887357

  15. Hydrated lime for metals immobilization and explosives transformation: Treatability study.

    PubMed

    Martin, W Andy; Larson, S L; Nestler, C C; Fabian, G; O'Connor, G; Felt, D R

    2012-05-15

    Fragmentation grenades contain Composition B (RDX and TNT) within a steel shell casing. There is the potential for off-site migration of high explosives and metals from hand grenade training ranges by transport in surface water and subsurface transport in leachate. This treatability study used bench-scale columns and mesocosm-scale laboratory lysimeters to investigate the potential of hydrated lime as a soil amendment for in situ remediation of explosives and metals stabilization in hand grenade range soils. Compared to the unamended soil there was a 26-92% reduction of RDX in the leachate and runoff water from the lime treated soils and a 66-83% reduction of zinc in the leachate and runoff water samples; where the hand grenade range metals of concern were zinc, iron, and manganese. The amended soil was maintained at the target pH of greater than 10.5 for optimum explosives decomposition. The treatability study indicated a high potential of success for scale-up to an in situ field study. PMID:22445717

  16. Enhanced capacity of chitosan for transition-metal ions in sulphate-sulphuric acid solutions.

    PubMed

    Muzzarelli, R A; Rocchetti, R

    1974-11-01

    Batch measurements have shown that the collection yields of chitosan for chromium(III), iron(III), nickel, copper(II), zinc and mercury(II) from sulphuric acid solutions are higher when the solutions contain ammonium sulphate, or when chitosan conditioned in ammonium sulphate is used, particularly at pH 3.0 and 5.0. The contrary is verified for the oxy-anions vanadate, chromate and molybdate. Manganese is never collected. At pH 1.0 no collection occurs. A procedure for recycling chromatographic columns includes fixation of Cu or Ni from a sulphate solution at pH 3-5 on sulphate-conditioned chitosan, and elution with 0.1M sulphuric acid/0.1M ammonium sulphate at pH 1.0; the presence of sulphate in the eluent obviates the detrimental effect of sulphuric acid on the next cycle. Sulphate is the favoured counter-ion of the chelated cations and its action produces shorter chromatographic bands. The interaction of sulphate with chitosan is discussed in terms of crystallinity and steric distribution of the protonated amino-groups in the polymer. Data on the new diethylaminohydroxypropylcellulose are included. PMID:18961577

  17. [Effect of the change in sulphate and dissolved oxygen mass concentration on metal release in old cast iron distribution pipes].

    PubMed

    Wu, Yong-li; Shi, Bao-you; Sun, Hui-fang; Zhang, Zhi-huan; Gu, Jun-nong; Wang, Dong-sheng

    2013-09-01

    To understand the processes of corrosion by-product release and the consequent "red water" problems caused by the variation of water chemical composition in drinking water distribution system, the effect of sulphate and dissolved oxygen (DO) concentration on total iron release in corroded old iron pipe sections historically transporting groundwater was investigated in laboratory using small-scale pipe section reactors. The release behaviors of some low-level metals, such as Mn, As, Cr, Cu, Zn and Ni, in the process of iron release were also monitored. The results showed that the total iron and Mn release increased significantly with the increase of sulphate concentration, and apparent red water occurred when sulphate concentration was above 400 mg x L(-1). With the increase of sulfate concentration, the effluent concentrations of As, Cr, Cu, Zn and Ni also increased obviously, however, the effluent concentrations of these metals were lower than the influent concentrations under most circumstances, which indicated that adsorption of these metals by pipe corrosion scales occurred. Increasing DO within a certain range could significantly inhibit the iron release.

  18. Effects of sorption, sulphate reduction, and Phragmites australis on the removal of heavy metals in subsurface flow constructed wetland microcosms.

    PubMed

    Lesage, E; Rousseau, D P L; Van de Moortel, A; Tack, F M G; De Pauw, N; Verloo, M G

    2007-01-01

    The removal of Co, Ni, Cu and Zn from synthetic industrial wastewater was studied in subsurface flow constructed wetland microcosms filled with gravel or a gravel/straw mixture. Half of the microcosms were planted with Phragmites australis and half were left unplanted. All microcosms received low-strength wastewater (1 mg L(-1) of Co, Ni, and Zn, 0.5 mg L(-1) Cu, 2,000mg L(-1) SO4) during seven 14-day incubation batches. The pore water was regularly monitored at two depths for heavy metals, sulphate, organic carbon and redox potential. Sorption properties of gravel and straw were assessed in a separate experiment. A second series of seven incubation batches with high-strength wastewater (10 mg L(-1) of each metal, 2,000 mg L(-1) SO4) was then applied to saturate the substrate. Glucose was added to the gravel microcosms together with the high-strength wastewater. Sorption processes were responsible for metal removal during start-up, with the highest removal efficiencies in the gravel microcosms. The lower initial efficiencies in the gravel/straw microcosms were presumably caused by the decomposition of straw. However, after establishment of anaerobic conditions (Eh approximately -200 mV), precipitation as metal sulphides provided an additional removal pathway in the gravel/straw microcosms. The addition of glucose to gravel microcosms enhanced sulphate reduction and metal removal, although Phragmites australis negatively affected these processes in the top-layer of all microcosms.

  19. Stratification of Metal and Sulphate Loads in Acid Mine Drainage Receiving Water Dams - Variables Regionalization by Cluster Analysis.

    PubMed

    Grande, J A; de la Torre, M L; Valente, T; Fernández, J P; Borrego, J; Santisteban, M; Cerón, J C; Sánchez-Rodas, D

    2015-07-01

    The Sancho Reservoir (Iberian Pyrite Belt, SW Spain) is nourished by the waters of the river Meca, which is affected by acid mine drainage (AMD) processes from the abandoned Tharsis mine. The aim of the present work is to study the hydrochemical variations in this reservoir, in order to define potential stratification processes in metal load and sulphates. A stratified sampling from the surface, with one meter deep intervals to the bottom of the dam, was performed. The results show a clear stratification of temperature, pH, electric conductivity, dissolved oxygen, metal and sulphate loads associated with depth. There is an increase of metal loads at the bottom of the reservoir, though previous studies only detect iron. The proximity between pH and aluminium suggests that water chemistry is strongly influenced by aluminium precipitation processes. This indicates the buffer effect that aluminium exercises, which precipitates as amorphous or low crystalline phases, introducing hydrogen ions to the system, while alkalinity input tends to raise pH. PMID:26163498

  20. Frictional Dissipation Pathways Mediated by Hydrated Alkali Metal Ions.

    PubMed

    Gaisinskaya-Kipnis, Anastasia; Ma, Liran; Kampf, Nir; Klein, Jacob

    2016-05-17

    Frictional energy dissipation between sliding solid surfaces in aqueous media may proceed by different pathways. Using a surface force balance (SFB), we have examined systematically how such dissipation is mediated by the series of hydrated cations M(+) = Li(+), Na(+), and K(+) that are trapped between two atomically smooth, negatively charged, mica surfaces sliding across the ionic solutions over many orders of magnitude loading. By working at local contact pressures up to ca. 30 MPa (∼300 atm), up to 2 orders of magnitude higher than earlier studies, we could show that the frictional dissipation at constant sliding velocity, represented by the coefficient of sliding friction μM+, decreased as μLi+ > μNa+ ≳ μK+. This result contrasts with the expectation (in conceptual analogy with the Hofmeister series) that the lubrication would improve with the extent of ionic hydration, since that would have led to the opposite μM+ sequence. It suggests, rather, that frictional forces, even in such simple systems, can be dominated by rate-activated pathways where the size of the hydration shell becomes a dissipative liability, rather than by the hydration-shell dissipation expected via the hydration lubrication mechanism. PMID:27089022

  1. A comparison of carbon/energy and complex nitrogen sources for bacterial sulphate-reduction: potential applications to bioprecipitation of toxic metals as sulphides.

    PubMed

    White, C; Gadd, G M

    1996-08-01

    Detailed nutrient requirements were determined to maximise efficacy of a sulphate-reducing bacterial mixed culture for biotechnological removal of sulphate, acidity and toxic metals from waste waters. In batch culture, lactate produced the greatest biomass, while ethanol was more effective in stimulating sulphide production and acetate was less effective. The presence of additional bicarbonate and H2 only marginally stimulated sulphide production. The sulphide output per unit of biomass was greatest using ethanol as substrate. In continuous culture, ethanol and lactate were used directly as efficient substrates for sulphate reduction while acetate yielded only slow growth. Glucose was utilised following fermentation to organic acids and therefore had a deleterious effect on pH. Ethanol was selected as the most efficient substrate due to cost and efficient yield of sulphide. On ethanol, the presence of additional carbon sources had no effect on growth or sulphate reduction in batch culture but the presence of complex nitrogen sources (yeast extract or cornsteep) stimulated both. Cornsteep showed the strongest effect and was also preferred on cost grounds. In continuous culture, cornsteep significantly improved the yield of sulphate reduced per unit of ethanol consumed. These results suggest that the most efficient nutrient regime for bioremediation using sulphate-reducing bacteria required both ethanol as carbon source and cornsteep as a complex nitrogen source.

  2. Characterisation of products of tricalcium silicate hydration in the presence of heavy metals.

    PubMed

    Chen, Q Y; Hills, C D; Tyrer, M; Slipper, I; Shen, H G; Brough, A

    2007-08-25

    The hydration of tricalcium silicate (C(3)S) in the presence of heavy metal is very important to cement-based solidification/stabilisation (s/s) of waste. In this work, tricalcium silicate pastes and aqueous suspensions doped with nitrate salts of Zn(2+), Pb(2+), Cu(2+) and Cr(3+) were examined at different ages by X-ray powder diffraction (XRD), thermal analysis (DTA/TG) and (29)Si solid-state magic angle spinning/nuclear magnetic resonance (MAS/NMR). It was found that heavy metal doping accelerated C(3)S hydration, even though Zn(2+) doping exhibited a severe retardation effect at an early period of time of C(3)S hydration. Heavy metals retarded the precipitation of portlandite due to the reduction of pH resulted from the hydrolysis of heavy metal ions during C(3)S hydration. The contents of portlandite in the control, Cr(3+)-doped, Cu(2+)-doped, Pb(2+)-doped and Zn(2+)-doped C(3)S pastes aged 28 days were 16.7, 5.5, 5.5, 5.5, and <0.7%, respectively. Heavy metals co-precipitated with calcium as double hydroxides such as (Ca(2)Cr(OH)(7).3H(2)O, Ca(2)(OH)(4)4Cu(OH)(2).2H(2)O and CaZn(2)(OH)(6).2H(2)O). These compounds were identified as crystalline phases in heavy metal doping C(3)S suspensions and amorphous phases in heavy metal doping C(3)S pastes. (29)Si NMR data confirmed that heavy metals promoted the polymerisation of C-S-H gel in 1-year-old of C(3)S pastes. The average numbers of Si in C-S-H gel for the Zn(2+)-doped, Cu(2+)-doped, Cr(3+)-doped, control, and Pb(2+)-doped C(3)S pastes were 5.86, 5.11, 3.66, 3.62, and 3.52. And the corresponding Ca/Si ratios were 1.36, 1.41, 1.56, 1.57 and 1.56, respectively. This study also revealed that the presence of heavy metal facilitated the formation of calcium carbonate during C(3)S hydration process in the presence of carbon dioxide.

  3. Evaluation of the thermodynamic properties of hydrated metal oxide nanoparticles by INS techniques

    SciTech Connect

    Spencer, Elinor; Ross, Dr. Nancy; Parker, Stewart F.; Kolesnikov, Alexander I

    2013-01-01

    In this contribution we will present a detailed methodology for the elucidation of the following aspects of the thermodynamic properties of hydrated metal oxide nanoparticles from high-resolution, low-temperature inelastic neutron scattering (INS) data: (i) the isochoric heat capacity and entropy of the hydration layers both chemi- and physisorbed to the particle surface; (ii) the magnetic contribution to the heat capacity of the nanoparticles. This will include the calculation of the vibrational density of states (VDOS) from the raw INS spectra, and the subsequent extraction of the thermodynamic data from the VDOS. This technique will be described in terms of a worked example namely, cobalt oxide (Co3O4 and CoO). To complement this evaluation of the physical properties of metal oxide nanoparticle systems, we will emphasise the importance of high-resolution, high-energy INS for the determination of the structure and dynamics of the water species, namely molecular (H2O) and dissociated water (OH, hydroxyl), confined to the oxide surfaces. For this component of the chapter we will focus on INS investigations of hydrated isostructural rutile (a-TiO2) and cassiterite (SnO2) nanoparticles. We will complete this discussion of nanoparticle analysis by including an appraisal of the INS instrumentation employed in such studies with particular focus on TOSCA [ISIS, Rutherford Appleton Laboratory (RAL), U.K.] and the newly developed spectrometer SEQUOIA [SNS, Oak Ridge National Laboratory (ORNL), U.S.A].

  4. Structural and magnetic studies on heavy-metal-adsorbing iron sulphide nanoparticles produced by sulphate-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Watson, J. H. P.; Cressey, B. A.; Roberts, A. P.; Ellwood, D. C.; Charnock, J. M.; Soper, A. K.

    2000-05-01

    In previous and in work to be published, it has been shown that iron sulphide material, produced by sulphate-reducing bacteria (SRB), is an excellent adsorbent for a wide range of heavy metals. The material adsorbs between 100 and 400 mg g -1 and residual levels in solutions can be of the order of pg per litre. Further, strongly magnetic forms of this material can now be produced which can be effectively and cheaply removed from suspension together with the adsorbate by magnetic separation. This paper examines the structure of weakly magnetic and strongly magnetic iron sulphide material produced by SRB with a view to increasing the understanding of its adsorbent and the magnetic properties. The structural properties have been examined using high-resolution imaging and electron diffraction in a transmission electron microscope (TEM), the measurements of magnetisation versus field and temperature, extended X-ray absorption fine-structure (EXAFS) spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy and neutron diffraction. Before drying the surface area of both the weakly magnetic and the strongly magnetic iron sulphide is of the order of 400-500 m 2 g -1 as revealed by the magnetic properties, neutron scattering and the adsorption of a number of heavy metals. After freeze-drying the surface area falls to between 18 and 19 m 2 g -1. The initial inocula came from a semi-saline source and when fed with nutrient containing Fe 2+ and Fe 3+ produced a weakly magnetic iron sulphide (Watson et al., Minerals Eng. 8 (1995) 1097) and a few % of a more strongly magnetic material. Further work using a novel method (Keller-Besrest, Collin, J. Solid State Chem. 84 (1990) 211) produced a strongly magnetic iron sulphide material. EXAFS and XANES spectroscopy revealed (Keller-Besrest and Collin, 1990) that the weakly magnetic iron sulphide material had the Ni-As structure in which the Fe is tetrahedrally coordinated with the composition Fe 1- xS. The strongly

  5. Communication: Evidence of hydrated electrons injected by a metallic electrode in a high voltage system

    NASA Astrophysics Data System (ADS)

    Perles, Carlos Eduardo; Volpe, Pedro Luiz Onófrio

    2010-12-01

    In this work it a strong evidence of the hydrated electrons production was shown in a film of condensed water, by directing the injection of electrons in localized and/or delocalized water electronic states using a system of high voltage made in laboratory. The results show that the water layers on the silica particles are electrically charged by injection of electrons from a metal electrode when silica is placed in high electric field. This charging process also appears to depend on the thickness of these water layers and of the spatial arrangement required by the silica surface.

  6. Metal-Free Markovnikov-Type Alkyne Hydration under Mild Conditions.

    PubMed

    Liu, Wenbo; Wang, Haining; Li, Chao-Jun

    2016-05-01

    A Markovnikov-type alkyne hydration protocol is presented using 20% CF3SO3H (TfOH) as the catalyst under unprecedented mild conditions applicable to various alkynes, including terminal arylalkynes, terminal nonfunctionalized aliphatic alkynes, and internal alkynes with excellent regioselectivity in good to excellent yields (average yields >85%). The reaction procedure operates under mild conditions (25-70 °C), with broad functional group compatibility, and uses only slightly more than a stoichiometric amount of water in the absence of any transition metal. The success of this protocol hinges upon the utilization of trifluoroethanol as the solvent. PMID:27082159

  7. Removal of nickel and cadmium from battery waste by a chemical method using ferric sulphate.

    PubMed

    Jadhav, Umesh U; Hocheng, Hong

    2014-01-01

    The removal of nickel (Ni) and cadmium (Cd) from spent batteries was studied by the chemical method. A novel leaching system using ferric sulphate hydrate was introduced to dissolve heavy metals in batteries. Ni-Cd batteries are classified as hazardous waste because Ni and Cd are suspected carcinogens. More efficient technologies are required to recover metals from spent batteries to minimize capital outlay, environmental impact and to respond to increased demand. The results obtained demonstrate that optimal conditions, including pH, concentration of ferric sulphate, shaking speed and temperature for the metal removal, were 2.5, 60 g/L, 150 rpm and 30 degrees C, respectively. More than 88 (+/- 0.9) and 84 (+/- 2.8)% of nickel and cadmium were recovered, respectively. These results suggest that ferric ion oxidized Ni and Cd present in battery waste. This novel process provides a possibility for recycling waste Ni-Cd batteries in a large industrial scale. PMID:24701923

  8. Past and future seasonal variation in pH and metal concentrations in runoff from river basins on acid sulphate soils in Western Finland.

    PubMed

    Saarinen, Tuomas S; Kløve, Bjørn

    2012-01-01

    Drainage of acid sulphate soils (ASS) increases oxidation, leading to extensive leaching of acidity and metals to rivers (Al, Cd, Cr, Fe, Ni and Zn). This is often apparent during high runoff periods in spring and autumn after long dry periods with low groundwater levels and associated ASS oxidation. Regression models were used to study changes in these water quality variables according to various discharge scenarios. The knowledge of seasonal patterns of water quality variables in future is important for planning land use of the catchments in relation to WFD of European Union. The data showed that river water acidity (pH and metals) increased with discharge, with the correlation being strongest in low runoff periods in winter and summer and less clear in spring. With future climate change, river acidity can increase radically, especially during winters following extremely dry summers, and pH and metal peaks may occur even during winter.

  9. Analytical applications of condensed phosphoric acid-III Iodometric determination of sulphur after reduction of sulphate with sodium hypophosphite and either tin metal or potassium iodide in condensed phosphoric acid.

    PubMed

    Mizoguchi, T; Iwahori, H; Ishii, H

    1980-06-01

    Novel methods for the reduction of sulphate to hydrogen sulphide with hypophosphite-tin metal or hypophosphite-iodide in condensed phosphoric acid (CPA) are proposed. The reduction of sulphate with hypophosphite alone does not proceed quantitatively. Sulphate, however, is quantitatively decomposed with hypophosphite when tin metal or potassium iodide is used together with it. The determination of sulphur by the hypophosphite-tin metal-CPA and tin(II)-CPA methods is interfered with by copper on account of the stabilization of copper(I) sulphide, but this interference can be eliminated by adding iodide, e.g. potassium and lead salts. Alum and barytes are quantitatively decomposed within 15 min at 140 and 280 degrees , respectively. The hydrogen sulphide evolved is absorbed in zinc acetate solution at pH 4.5 and then determined by iodometry.

  10. Calcium sulphate in ammonium sulphate solution

    USGS Publications Warehouse

    Sullivan, E.C.

    1905-01-01

    Calcium sulphate, at 25?? C., is two-thirds as soluble in dilute (o.i mol per liter) and twice as soluble in concentrated (3 mois per liter) ammonium sulphate solution as in water. The specific electric conductivity of concentrated ammonium sulphate solutions is lessened by saturating with calcium sulphate. Assuming that dissociation of ammonium sulphate takes place into 2NH4?? and SO4" and of calcium sulphate into Ca and SO4" only, and that the conductivity is a measure of such dissociation, the solubility of calcium sulphate in dilute ammonium sulphate solutions is greater than required by the mass-law. The conductivity of the dilute mixtures may be accurately calculated by means of Arrhenius' principle of isohydric solutions. In the data obtained in these calculations, the concentration of non-dissociated calcium sulphate decreases with increasing ammonium sulphate. The work as a whole is additional evidence of the fact that we are not yet in possession of all the factors necessary for reconciling the mass-law to the behavior of electrolytes. The measurements above described were made in the chemical laboratory of the University of Michigan.

  11. Simulation of substrate erosion and sulphate assimilation by Martian low-viscosity lava flows: implications for the genesis of precious metal-rich sulphide mineralisation on Mars

    NASA Astrophysics Data System (ADS)

    Baumgartner, Raphael; Baratoux, David; Gaillard, Fabrice; Fiorentini, Marco

    2016-04-01

    On Earth, high temperature mafic to ultramafic lava flows, such as komatiites and ferropicrites of the Archean and Proterozic eons, can be hosts to Ni-Cu-PGE sulphide mineralisation. Mechanical/thermo-mechanical erosion and assimilation of sulphur-rich crustal rocks is ascribed as the principal mechanism that leads to sulphide supersaturation, batch segregation and subsequent accumulation of metal-enriched magmatic sulphides (e.g., Bekker et al., Science, 2009). In order to investigate the likelihood of the occurrence of similar sulphide mineralisation in extraterrestrial magmatic systems, we numerically modelled erosion and assimilation during the turbulent emplacement of Martian lavas, some of which display chemical and rheological analogies with terrestrial komatiites and ferropicrites, on a variety of consolidated sedimentary sulphate-rich substrates. The modelling approach relies on the integration of i) mathematical lava erosion models for turbulent flows (Williams et al., J. Geophys. Res., 1998), ii) thermodynamic volatile degassing models (Gaillard et al., Space Sci. Rev., 2013), and iii) formulations on the stability of sulphides (Fortin et al., Geochim. Cosmochim. Acta, 2015). A series of scenarios are examined in which various Martian mafic to ultramafic mantle-derived melts emplace over, and assimilate consolidated sulphate-rich substrates, such as the sedimentary lithologies (i.e., conglomerates, sandstones and mudstones) recently discovered at the Gale Crater landing site. Our modellings show that lavas emplacing over consolidated sedimentary substrate rather than stiff basaltic crust, are governed by relatively high cooling and substrate erosion rates. The rapid assimilation of sulphate, which serves as a strongly oxidising agent, could result in dramatic sulphur loss due to increased volatile degassing rates at fO2 ≳QFM-1. This effect is further enhanced with increased temperature. Nevertheless, sulphide supersaturation in the way of sulphate

  12. Toxicity of metal oxide nanoparticles in Escherichia coli correlates with conduction band and hydration energies.

    PubMed

    Kaweeteerawat, Chitrada; Ivask, Angela; Liu, Rong; Zhang, Haiyuan; Chang, Chong Hyun; Low-Kam, Cecile; Fischer, Heidi; Ji, Zhaoxia; Pokhrel, Suman; Cohen, Yoram; Telesca, Donatello; Zink, Jeffrey; Mädler, Lutz; Holden, Patricia A; Nel, Andre; Godwin, Hilary

    2015-01-20

    Metal oxide nanoparticles (MOx NPs) are used for a host of applications, such as electronics, cosmetics, construction, and medicine, and as a result, the safety of these materials to humans and the environment is of considerable interest. A prior study of 24 MOx NPs in mammalian cells revealed that some of these materials show hazard potential. Here, we report the growth inhibitory effects of the same series of MOx NPs in the bacterium Escherichia coli and show that toxicity trends observed in E. coli parallel those seen previously in mammalian cells. Of the 24 materials studied, only ZnO, CuO, CoO, Mn2O3, Co3O4, Ni2O3, and Cr2O3 were found to exert significant growth inhibitory effects; these effects were found to relate to membrane damage and oxidative stress responses in minimal trophic media. A correlation of the toxicological data with physicochemical parameters of MOx NPs revealed that the probability of a MOx NP being toxic increases as the hydration enthalpy becomes less negative and as the conduction band energy approaches those of biological molecules. These observations are consistent with prior results observed in mammalian cells, revealing that mechanisms of toxicity of MOx NPs are consistent across two very different taxa. These results suggest that studying nanotoxicity in E. coli may help to predict toxicity patterns in higher organisms. PMID:25563693

  13. Sulphate in pregnancy.

    PubMed

    Dawson, Paul A; Elliott, Aoife; Bowling, Francis G

    2015-03-01

    Sulphate is an obligate nutrient for healthy growth and development. Sulphate conjugation (sulphonation) of proteoglycans maintains the structure and function of tissues. Sulphonation also regulates the bioactivity of steroids, thyroid hormone, bile acids, catecholamines and cholecystokinin, and detoxifies certain xenobiotics and pharmacological drugs. In adults and children, sulphate is obtained from the diet and from the intracellular metabolism of sulphur-containing amino acids. Dietary sulphate intake can vary greatly and is dependent on the type of food consumed and source of drinking water. Once ingested, sulphate is absorbed into circulation where its level is maintained at approximately 300 μmol/L, making sulphate the fourth most abundant anion in plasma. In pregnant women, circulating sulphate concentrations increase by twofold with levels peaking in late gestation. This increased sulphataemia, which is mediated by up-regulation of sulphate reabsorption in the maternal kidneys, provides a reservoir of sulphate to meet the gestational needs of the developing foetus. The foetus has negligible capacity to generate sulphate and thereby, is completely reliant on sulphate supply from the maternal circulation. Maternal hyposulphataemia leads to foetal sulphate deficiency and late gestational foetal death in mice. In humans, reduced sulphonation capacity has been linked to skeletal dysplasias, ranging from the mildest form, multiple epiphyseal dysplasia, to achondrogenesis Type IB, which results in severe skeletal underdevelopment and death in utero or shortly after birth. Despite being essential for numerous cellular and metabolic functions, the nutrient sulphate is largely unappreciated in clinical settings. This article will review the physiological roles and regulation of sulphate during pregnancy, with a particular focus on animal models of disturbed sulphate homeostasis and links to human pathophysiology. PMID:25746011

  14. Sulphate in Pregnancy

    PubMed Central

    Dawson, Paul A.; Elliott, Aoife; Bowling, Francis G.

    2015-01-01

    Sulphate is an obligate nutrient for healthy growth and development. Sulphate conjugation (sulphonation) of proteoglycans maintains the structure and function of tissues. Sulphonation also regulates the bioactivity of steroids, thyroid hormone, bile acids, catecholamines and cholecystokinin, and detoxifies certain xenobiotics and pharmacological drugs. In adults and children, sulphate is obtained from the diet and from the intracellular metabolism of sulphur-containing amino acids. Dietary sulphate intake can vary greatly and is dependent on the type of food consumed and source of drinking water. Once ingested, sulphate is absorbed into circulation where its level is maintained at approximately 300 μmol/L, making sulphate the fourth most abundant anion in plasma. In pregnant women, circulating sulphate concentrations increase by twofold with levels peaking in late gestation. This increased sulphataemia, which is mediated by up-regulation of sulphate reabsorption in the maternal kidneys, provides a reservoir of sulphate to meet the gestational needs of the developing foetus. The foetus has negligible capacity to generate sulphate and thereby, is completely reliant on sulphate supply from the maternal circulation. Maternal hyposulphataemia leads to foetal sulphate deficiency and late gestational foetal death in mice. In humans, reduced sulphonation capacity has been linked to skeletal dysplasias, ranging from the mildest form, multiple epiphyseal dysplasia, to achondrogenesis Type IB, which results in severe skeletal underdevelopment and death in utero or shortly after birth. Despite being essential for numerous cellular and metabolic functions, the nutrient sulphate is largely unappreciated in clinical settings. This article will review the physiological roles and regulation of sulphate during pregnancy, with a particular focus on animal models of disturbed sulphate homeostasis and links to human pathophysiology. PMID:25746011

  15. Metal halogen battery construction with improved technique for producing halogen hydrate

    DOEpatents

    Fong, Walter L.; Catherino, Henry A.; Kotch, Richard J.

    1983-01-01

    An improved electrical energy storage system comprising, at least one cell having a positive electrode and a negative electrode separated by aqueous electrolyte, a store means wherein halogen hydrate is formed and stored as part of an aqueous material having a liquid level near the upper part of the store, means for circulating electrolyte through the cell, conduit means for transmitting halogen gas formed in the cell to a hydrate forming apparatus associated with the store, said hydrate forming apparatus including, a pump to which there is introduced quantities of the halogen gas and chilled water, said pump being located in the store and an outlet conduit leading from the pump and being substantially straight and generally vertically disposed and having an exit discharge into the gas space above the liquid level in the store, and wherein said hydrate forming apparatus is highly efficient and very resistant to plugging or jamming. The disclosure also relates to an improved method for producing chlorine hydrate in zinc chlorine batteries.

  16. Physicochemical characterization of nedocromil bivalent metal salt hydrates. 3. Nedocromil calcium.

    PubMed

    Zhu, H; Halfen, J A; Young, V G; Padden, B E; Munson, E J; Menon, V; Grant, D J

    1997-12-01

    A crystalline pentahydrate and a crystalline 8/3 hydrate of nedocromil calcium (NC) were prepared. The relationships between these solid phases and the nature of the water interactions in their structures were studied through characterization by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Karl Fischer titrimetry (KFT), hot-stage microscopy (HSM), ambient- or variable-temperature powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) spectroscopy, solid-state nuclear magnetic resonance (SSNMR) spectroscopy, water uptake at various relative humidities (RH), intrinsic dissolution rate (IDR) and solubility measurements. The solubility and intrinsic dissolution rate of the pentahydrate in water at 25 degrees C are approximately 17% greater than the corresponding values for the 8/3 hydrate, corresponding to a greater Gibbs free energy of only 380 J.mol-1 (91 cal.mol-1) for the pentahydrate. The results of DSC, TGA, and FTIR and SSNMR spectroscopy indicate that the water of hydration is more loosely bound in the pentahydrate than in the 8/3 hydrate. On increasing the temperature in open-pan DSC and TGA, the water in the pentahydrate is released in four steps (three steps in crimped pans), whereas the water in the 8/3 hydrate is released in three steps (three steps also in crimped pans). These three stepwise dehydrations are fundamentally explained by their different water environments in the crystal structure of the 8/3 hydrate, which was determined by single-crystal XRD [crystal data: triclinic, space group P1, a = 13.2381(3) A, b = 13.3650(2) A, c = 17.8224(2) A, alpha = 68.202(1) degrees, beta = 86.894(1) degrees, gamma = 82.969(1) degrees, Z = 6]. The asymmetric unit contains three nedocromil anions and three calcium cations associated with eight water molecules. The nedocromil anions act as polyfunctional ligands to the Ca2+ ions, coordinating through both the carbonyl oxygen and the carboxylate oxygen atoms. The molecular

  17. Zinc hydroxide sulphate and its transformation to crystalline zinc oxide.

    PubMed

    Moezzi, Amir; Cortie, Michael B; McDonagh, Andrew M

    2013-10-28

    The thermal transformation of zinc hydroxide sulphate hydrate to zinc oxide has been examined using synchrotron X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and surface area measurements. By collecting X-ray diffraction data in situ, we found that the dehydration of zinc hydroxide sulphate pentahydrate proceeded in discrete steps to form anhydrous zinc hydroxide sulphate. This compound then decomposed to a mixture of zinc oxide and a compound tentatively identified as Zn3(OH)2(SO4)2 at ~235 °C. At ~360 °C, the final dehydroxylation occurred with the formation of zinc oxy-sulphate, Zn3O(SO4)2, which then decomposed to ZnO at about ~800 °C. Interruption of the dehydration process can be used to synthesize the intermediate compounds.

  18. Magnesium sulphate salts and the history of water on Mars.

    PubMed

    Vaniman, David T; Bish, David L; Chipera, Steve J; Fialips, Claire I; Carey, J William; Feldman, William C

    2004-10-01

    Recent reports of approximately 30 wt% of sulphate within saline sediments on Mars--probably occurring in hydrated form--suggest a role for sulphates in accounting for equatorial H2O observed in a global survey by the Odyssey spacecraft. Among salt hydrates likely to be present, those of the MgSO4*nH2O series have many hydration states. Here we report the exposure of several of these phases to varied temperature, pressure and humidity to constrain their possible H2O contents under martian surface conditions. We found that crystalline structure and H2O content are dependent on temperature-pressure history, that an amorphous hydrated phase with slow dehydration kinetics forms at <1% relative humidity, and that equilibrium calculations may not reflect the true H2O-bearing potential of martian soils. Mg sulphate salts can retain sufficient H2O to explain a portion of the Odyssey observations. Because phases in the MgSO4*nH2O system are sensitive to temperature and humidity, they can reveal much about the history of water on Mars. However, their ease of transformation implies that salt hydrates collected on Mars will not be returned to Earth unmodified, and that accurate in situ analysis is imperative.

  19. Direct measurement of the Mn(II) hydration state in metal complexes and metalloproteins through 17O NMR line widths.

    PubMed

    Gale, Eric M; Zhu, Jiang; Caravan, Peter

    2013-12-11

    Here we describe a simple method to estimate the inner-sphere hydration state of the Mn(II) ion in coordination complexes and metalloproteins. The line width of bulk H2(17)O is measured in the presence and absence of Mn(II) as a function of temperature, and transverse (17)O relaxivities are calculated. It is demonstrated that the maximum (17)O relaxivity is directly proportional to the number of inner-sphere water ligands (q). Using a combination of literature data and experimental data for 12 Mn(II) complexes, we show that this method provides accurate estimates of q with an uncertainty of ±0.2 water molecules. The method can be implemented on commercial NMR spectrometers working at fields of 7 T and higher. The hydration number can be obtained for micromolar Mn(II) concentrations. We show that the technique can be extended to metalloproteins or complex:protein interactions. For example, Mn(II) binds to the multimetal binding site A on human serum albumin with two inner-sphere water ligands that undergo rapid exchange (1.06 × 10(8) s(-1) at 37 °C). The possibility of extending this technique to other metal ions such as Gd(III) is discussed.

  20. Hydrate detection

    SciTech Connect

    Dillon, W.P.; Ahlbrandt, T.S.

    1992-06-01

    Project objectives were: (1) to create methods of analyzing gas hydrates in natural sea-floor sediments, using available data, (2) to make estimates of the amount of gas hydrates in marine sediments, (3) to map the distribution of hydrates, (4) to relate concentrations of gas hydrates to natural processes and infer the factors that control hydrate concentration or that result in loss of hydrate from the sea floor. (VC)

  1. Hydrate detection

    SciTech Connect

    Dillon, W.P.; Ahlbrandt, T.S.

    1992-01-01

    Project objectives were: (1) to create methods of analyzing gas hydrates in natural sea-floor sediments, using available data, (2) to make estimates of the amount of gas hydrates in marine sediments, (3) to map the distribution of hydrates, (4) to relate concentrations of gas hydrates to natural processes and infer the factors that control hydrate concentration or that result in loss of hydrate from the sea floor. (VC)

  2. Sub-Chronic Oral Exposure to Iridium (III) Chloride Hydrate in Female Wistar Rats: Distribution and Excretion of the Metal

    PubMed Central

    Iavicoli, Ivo; Fontana, Luca; Bergamaschi, Antonio; Conti, Marcelo Enrique; Pino, Anna; Mattei, Daniela; Bocca, Beatrice; Alimonti, Alessandro

    2012-01-01

    Iridium tissue distribution and excretion in female Wistar rats following oral exposure to iridium (III) chloride hydrate in drinking water (from 1 to 1000 ng/ml) in a sub-chronic oral study were determined. Samples of urine, feces, blood and organs (kidneys, liver, lung, spleen and brain) were collected at the end of exposure. The most prominent fractions of iridium were retained in kidney and spleen; smaller amounts were found in lungs, liver and brain. Iridium brain levels were lower than those observed in other tissues but this finding can support the hypothesis of iridium capability to cross the blood brain barrier. The iridium kidney levels rose significantly with the administered dose. At the highest dose, important amounts of the metal were found in serum, urine and feces. Iridium was predominantly excreted via feces with a significant linear correlation with the ingested dose, which is likely due to low intestinal absorption of the metal. However, at the higher doses iridium was also eliminated through urine. These findings may be useful to help in the understanding of the adverse health effects, particularly on the immune system, of iridium dispersed in the environment as well as in identifying appropriate biological indices of iridium exposure. PMID:22942873

  3. Heavily-hydrated lithic clasts in CH chondrites and the related, metal-rich chondrites Queen Alexandra Range 94411 and Hammadah al Hamra 237

    NASA Astrophysics Data System (ADS)

    Greshake, A.; Krot, A. N.; Meibom, A.; Weisberg, M. K.; Zolensky, M. E.; Keil, K.

    2002-02-01

    Fine-grained, heavily-hydrated lithic clasts in the metal-rich (CB) chondrites Queen Alexandra Range (QUE) 94411 and Hammadah al Hamra 237 and CH chondrites, such as Patuxent Range (PAT) 91546 and Allan Hills (ALH) 85085, are mineralogically similar suggesting genetic relationship between these meteorites. These clasts contain no anhydrous silicates and consist of framboidal and platelet magnetite, prismatic sulfides (pentlandite and pyrrhotite), and Fe-Mn-Mg-bearing Ca-carbonates set in a phyllosilicate-rich matrix. Two types of phyllosilicates were identified: serpentine, with basal spacing of ?0.73 nm, and saponite, with basal spacings of about 1.1-1.2 nm. Chondrules and FeNi-metal grains in CB and CH chondrites are believed to have formed at high temperature (>1300 K) by condensation in a solar nebula region that experienced complete vaporization. The absence of aqueous alteration of chondrules and metal grains in CB and CH chondrites indicates that the clasts experienced hydration in an asteroidal setting prior to incorporation into the CH and CB parent bodies. The hydrated clasts were either incorporated during regolith gardening or accreted together with chondrules and FeNi-metal grains after these high-temperature components had been transported from their hot formation region to a much colder region of the solar nebula.

  4. Reactions of Hexa-aquo Transition Metal Ions with the Hydrated Electron up to 300 °C.

    PubMed

    Kanjana, Kotchaphan; Courtin, Bruce; MacConnell, Ashley; Bartels, David M

    2015-11-12

    Reactions of the hydrated electron with divalent aqueous transition-metal ions, Cd(2+), Zn(2+), Ni(2+), Cu(2+), Co(2+), Fe(2+), and Mn(2+), were studied using a pulse radiolysis technique. The kinetics study was carried out at a constant pressure of 120 bar with temperatures up to 300 °C. The rate constants at room temperature agree with those reported in the literature. The reaction of Cd(2+) is approximately diffusion-limited, but none of the first-row transition-metal ion reactions are diffusion-controlled at any temperature studied. The activation energies obtained from the Arrhenius plots are in the range 14.5-40.6 kJ/mol. Pre-exponential factors are quite large, between 1 × 10(13) and 7 × 10(15) M(-1) s(-1). There appears to be a large degree of entropy-enthalpy compensation in the activation of Zn(2+), Ni(2+), Co(2+), and Cu(2+), as the larger pre-exponential factors strongly correlate with higher activation energy. Saturation of the ionic strength effect suggests that these reactions could be long-range nonadiabatic electron "jumps", but Marcus theory is incompatible with direct formation of ground state (M(+))aq ions. A self-consistent explanation is that electron transfer occurs to excited states derived from the metal 4s orbitals. The ionic strength effect in the Mn(2+) and Fe(2+) reactions suggests that these proceed by short-range adiabatic electron attachment involving breakdown of the water coordination shell. PMID:26530531

  5. A QUANTUM MECHANICAL STUDY OF THE PROTONATION AND COVALENT HYDRATION OF QUINAZOLINE IN THE PRESENCE OF METAL CATIONS

    EPA Science Inventory

    We have investigated the protonation and reversible covalent hydration of quinazoline in the presence of Li+, Na+, and Ca2+ ions using ab initio quantum mechanical calculations at the MP2/6-31G**//HF/6-31G*level of theory. Proton affinities, enthalpies of hydration at 298.15K (DH...

  6. Separation of rare earths from transition metals by liquid-liquid extraction from a molten salt hydrate to an ionic liquid phase.

    PubMed

    Rout, Alok; Binnemans, Koen

    2014-02-28

    The solvent extraction of trivalent rare-earth ions and their separation from divalent transition metal ions using molten salt hydrates as the feed phase and an undiluted fluorine-free ionic liquid as the extracting phase were investigated in detail. The extractant was tricaprylmethylammonium nitrate, [A336][NO3], and the hydrated melt was calcium nitrate tetrahydrate, Ca(NO3)2·4H2O. The extraction behavior of rare-earth ions was studied for solutions of individual elements, as well as for mixtures of rare earths in the hydrated melt. The influence of different extraction parameters was investigated: the initial metal loading in the feed phase, percentage of water in the feed solution, equilibration time, and the type of hydrated melt. The extraction of rare earths from Ca(NO3)2·4H2O was compared with extraction from CaCl2·4H2O by [A336][Cl] (Aliquat 336). The nitrate system was found to be the better one. The extraction and separation of rare earths from the transition metals nickel, cobalt and zinc were also investigated. Remarkably high separation factors of rare-earth ions over transition metal ions were observed for extraction from Ca(NO3)2·4H2O by the [A336][NO3] extracting phase. Furthermore, rare-earth ions could be separated efficiently from transition metal ions, even in melts with very high concentrations of transition metal ions. Rare-earth oxides could be directly dissolved in the Ca(NO3)2·4H2O phase in the presence of small amounts of Al(NO3)3·9H2O or concentrated nitric acid. The efficiency of extraction after dissolving the rare-earth oxides in the hydrated nitrate melt was identical to extraction from solutions with rare-earth nitrates dissolved in the molten phase. The stripping of the rare-earth ions from the loaded ionic liquid phase and the reuse of the recycled ionic liquid were also investigated in detail.

  7. Sources and impact of sulphate on groundwaters of Triassic carbonate aquifers, Upper Silesia, Poland

    NASA Astrophysics Data System (ADS)

    Samborska, Katarzyna; Halas, Stanislaw; Bottrell, Simon H.

    2013-04-01

    under threat from both natural sources, i.e. metal sulphide oxidation and gypsum dissolution. Analysis of the mathematical models analysis shows that the first process is the predominant source of sulphate in groundwater. However, the highest concentrations of dissolved sulphate are positively correlated with the increasing proportion of sulphate derived from gypsum dissolution. Moreover, one should keep in mind that natural processes might be anthropogenically accelerated due to variable water demands and groundwater abstraction. Eventually, the statistically second-order source of sulphate - rainfall might contain surface-derived contaminants, and its contribution to the total load of sulphate might indirectly indicate the vulnerability of aquifers for the pollution.

  8. Study on third order nonlinear optical properties of a metal organic complex-Monothiourea-cadmium Sulphate Dihydrate single crystals grown in silica gel

    NASA Astrophysics Data System (ADS)

    Sivanandan, T.; Kalainathan, S.

    2015-04-01

    The third order nonlinear optical properties of Monothiourea-cadmium Sulphate Dihydrate crystal were measured using a He-Ne laser (λ=632.8 nm) by a Z-scan technique. The magnitude of nonlinear refractive index (n2) and nonlinear absorption coefficient was found to be 4.4769×10-11 m2/W and 1.233×10-2 m/W respectively. The third order non-linear optical susceptibility χ(3) was found to be in the order of 3.6533×10-2 esu. The negative sign of non-linear refractive index shows the self-defocusing nature of the gel grown crystal. The second-order molecular hyperpolarizability γ of the grown crystal is 1.2822×10-33 esu. Laser damage threshold was measured by using an Nd: YAG laser (1064 nm). Photoconductivity studies of the gel grown crystal revealed that the crystal possesses positive photoconducting nature. The results obtained from Z-scan, laser damage threshold and photoconducting studies reveal that the crystal can be a possible candidate material for photonics device, optical switches, and optical power limiting application.

  9. Effects of inorganic acids and divalent hydrated metal cations (Mg(2+), Ca(2+), Co(2+), Ni(2+)) on γ-AlOOH sol-gel process.

    PubMed

    Zhang, Jian; Xia, Yuguo; Zhang, Li; Chen, Dairong; Jiao, Xiuling

    2015-11-01

    In-depth understanding of the sol-gel process plays an essential role in guiding the preparation of new materials. Herein, the effects of different inorganic acids (HCl, HNO3 and H2SO4) and divalent hydrated metal cations (Mg(2+), Ca(2+), Co(2+), Ni(2+)) on γ-AlOOH sol-gel process were studied based on experiments and density functional theory (DFT) calculations. In these experiments, the sol originating from the γ-AlOOH suspension was formed only with the addition of HCl and HNO3, but not with H2SO4. Furthermore, the DFT calculations showed that the strong adsorption of HSO4(-) on the surface of the γ-AlOOH particles, and the hydrogen in HSO4(-) pointing towards the solvent lead to an unstable configuration of electric double layer (EDL). In the experiment, the gelation time sequence of γ-AlOOH sol obtained by adding metal ions changed when the ionic strength was equal to or greater than 0.198 mol kg(-1). The DFT calculations demonstrated that the adsorption energy of hydrated metal ions on the γ-AlOOH surface can actually make a difference in the sol-gel process.

  10. Aluminum and sulphate removal by a highly Al-resistant dissimilatory sulphate-reducing bacteria community.

    PubMed

    Martins, Mónica; Taborda, Rita; Silva, Gonçalo; Assunção, Ana; Matos, António Pedro; Costa, Maria Clara

    2012-09-01

    A highly Al-resistant dissimilatory sulphate-reducing bacteria community was isolated from sludge of the wetland of Urgeiriça mine (community W). This community showed excellent sulphate removal at the presence of Al³⁺. After 27 days of incubation, 73, 86 and 81% of sulphate was removed in the presence of 0.48, 0.90 and 1.30 mM of Al³⁺, respectively. Moreover, Al³⁺ was simultaneously removed: 55, 85 and 78% of metal was removed in the presence of 0.48, 0.90 and 1.30 mM of Al³⁺, respectively. The dissociation of aluminium-lactate soluble complexes due to lactate consumption by dissimilatory sulphate-reducing bacteria can be responsible for aluminum removal, which probably precipitates as insoluble aluminium hydroxide. Phylogenetic analysis of 16S rRNA gene showed that this community was mainly composed by bacteria closely related to Desulfovibrio desulfuricans. However, bacteria affiliated to Proteus and Ralstonia were also present in the community.

  11. Corrosion Performance of Inconel 625 in High Sulphate Content

    NASA Astrophysics Data System (ADS)

    Ismail, Azzura

    2016-05-01

    Inconel 625 (UNS N06625) is a type of nickel-chromium-molybdenum alloy with excellent corrosion resistance in a wide range of corrosive media, being especially resistant to pitting and crevice corrosion. However, in aggressive environment, Inconel 625 will suffer corrosion attack like other metals. This research compared the corrosion performance of Inconel 625 when exposed to higher sulphate content compared to real seawater. The results reveal that Inconel 625 is excellent in resist the corrosion attack in seawater. However, at increasing temperature, the corrosion resistance of this metal decrease. The performance is same in seawater with high sulphate content at increasing temperature. It can be concluded that sulphate promote perforation on Inconel 625 and become aggressive agents that accelerate the corrosion attack.

  12. Deterioration of hardened cement paste under combined sulphate-chloride attack investigated by synchrotron XRD

    NASA Astrophysics Data System (ADS)

    Stroh, J.; Meng, B.; Emmerling, F.

    2016-06-01

    The exact mechanisms of the phase transitions caused by a combined sulphate-chloride attack are discussed controversially. The main points concern the mutual influences of sulphate and chloride ions during the secondary binding processes of these anions within cement hydrate phases. We simulated combined sulphate-chloride attack under laboratory conditions using solutions containing NaCl and Na2SO4 in different concentrations. Three sample compositions were used for the preparation of the specimens. In two of them, 30% of Portland cement was replaced by supplementary cementitious materials (fly ash, slag). The phase distribution in the samples was determined using synchrotron X-ray diffraction. The analysis with high spatial resolution allows the localisation of the secondary phase formation in the microstructural profile of the sample. A mechanism of the phase developments under combined sulphate-chloride attack is derived.

  13. Reduction on the anaerobic biological activity inhibition caused by heavy metals and sulphates in effluents through chemical precipitation with soda and lime.

    PubMed

    Alves, L de Carvalho; Cammarota, M C; De França, F P

    2006-12-01

    The School of Chemistry Environmental Technology Laboratory generates 43.4 1 of effluent with low pH (0.7) and high contents of COD (1908 mgO2 l(-1)), phenol (132.1 mg l(-1)), sulfate (36700 mg l(-1)) and heavy metals (28.2 mg Hg l(-1); 82.1 mg Cr(total) l(-1); 30.8 mg Cu l(-1); 57.4 mg Fe(total) l(-1); 16.2 mg Al l(-1)) weekly. These data show that this effluent presents high toxicity for biological treatment, with a physical-chemical step being necessary before a biological step. Preliminary studies showed that the most toxic constituents of the effluent were sulfate, phenol and total chromium. In this work, a chemical precipitation step with sodium hydroxide or lime was evaluated for the toxicity reduction on anaerobic microbial consortium. These experiments were carried out with increasing concentrations of alkalis in the effluent in order to obtain pH initial values of 8-12. Similar results were obtained for COD (15-28%), turbidity (95-98%), phenol (13-24%) and total chromium (99.8-99.9%) removals in each condition studied with soda or lime. Sulfate was only removed by precipitation with lime, obtaining reductions from 84 to 88%. The toxicity on the anaerobic sludge was studied employing specific methanogenic activity (SMA) analysis of raw and treated effluent (after chemical precipitation step). The SMA experiments showed that chemical precipitation at pH 8 reduces the toxic effect of the effluent on anaerobic microbial consortium three times (with soda) and thirteen times (with lime). These results indicate that precipitation with lime is more efficient at toxicity removal, however the produced sludge volume is around two times higher than that produced with soda.

  14. Reduction on the anaerobic biological activity inhibition caused by heavy metals and sulphates in effluents through chemical precipitation with soda and lime.

    PubMed

    Alves, L de Carvalho; Cammarota, M C; De França, F P

    2006-12-01

    The School of Chemistry Environmental Technology Laboratory generates 43.4 1 of effluent with low pH (0.7) and high contents of COD (1908 mgO2 l(-1)), phenol (132.1 mg l(-1)), sulfate (36700 mg l(-1)) and heavy metals (28.2 mg Hg l(-1); 82.1 mg Cr(total) l(-1); 30.8 mg Cu l(-1); 57.4 mg Fe(total) l(-1); 16.2 mg Al l(-1)) weekly. These data show that this effluent presents high toxicity for biological treatment, with a physical-chemical step being necessary before a biological step. Preliminary studies showed that the most toxic constituents of the effluent were sulfate, phenol and total chromium. In this work, a chemical precipitation step with sodium hydroxide or lime was evaluated for the toxicity reduction on anaerobic microbial consortium. These experiments were carried out with increasing concentrations of alkalis in the effluent in order to obtain pH initial values of 8-12. Similar results were obtained for COD (15-28%), turbidity (95-98%), phenol (13-24%) and total chromium (99.8-99.9%) removals in each condition studied with soda or lime. Sulfate was only removed by precipitation with lime, obtaining reductions from 84 to 88%. The toxicity on the anaerobic sludge was studied employing specific methanogenic activity (SMA) analysis of raw and treated effluent (after chemical precipitation step). The SMA experiments showed that chemical precipitation at pH 8 reduces the toxic effect of the effluent on anaerobic microbial consortium three times (with soda) and thirteen times (with lime). These results indicate that precipitation with lime is more efficient at toxicity removal, however the produced sludge volume is around two times higher than that produced with soda. PMID:17285944

  15. Chloral hydrate

    Integrated Risk Information System (IRIS)

    Chloral hydrate ; CASRN 302 - 17 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  16. Prolonged release terbutaline sulphate microcapsules.

    PubMed

    Manekar, N C; Puranik, P K; Joshi, S B

    1991-01-01

    Terbutaline sulphate microcapsules were prepared by coacervation-phase separation induced by solvent evaporation technique. The cellulose acetate phthalate was employed as coating material alone and in combination with ethyl cellulose. The prepared microcapsules were evaluated for their drug content, particle size distribution (microscopic method), flow properties, bulk density and in vitro dissolution. PMID:1798022

  17. Structures of Hydrated Alkali Metal Cations, M+(H2O)nAr (m = Li, Na, K, rb and Cs, n = 3-5), Using Infrared Photodissociation Spectroscopy and Thermodynamic Analysis

    NASA Astrophysics Data System (ADS)

    Ke, Haochen; van der Linde, Christian; Lisy, James M.

    2014-06-01

    Alkali metal cations play vital roles in chemical and biochemical systems. Lithium is widely used in psychiatric treatment of manic states and bipolar disorder; Sodium and potassium are essential elements, having major biological roles as electrolytes, balancing osmotic pressure on body cells and assisting the electroneurographic signal transmission; Rubidium has seen increasing usage as a supplementation for manic depression and depression treatment; Cesium doped compounds are used as essential catalysts in chemical production and organic synthesis. Since hydrated alkali metal cations are ubiquitous and the basic form of the alkali metal cations in chemical and biochemical systems, their structural and thermodynamic properties serve as the foundation for modeling more complex chemical and biochemical processes, such as ion transport and ion size-selectivity of ionophores and protein channels. By combining mass spectrometry and infrared photodissociation spectroscopy, we have characterized the structures and thermodynamic properties of the hydrated alkali metal cations, i.e. M+(H2O)nAr, (M = Li, Na, K, Rb and Cs, n = 3-5). Ab initio calculations and RRKM-EE (evaporative ensemble) calculations were used to assist in the spectral assignments and thermodynamic analysis. Results showed that the structures of hydrated alkali metal cations were determined predominantly by the competition between non-covalent interactions, i.e. the water---water hydrogen bonding interactions and the water---cation electrostatic interactions. This balance, however, is very delicate and small changes, i.e. different cations, different levels of hydration and different effective temperatures clearly impact the balance.

  18. The sulphate-reducing bacteria

    SciTech Connect

    Postgate, J.R.

    1984-01-01

    This monograph surveys knowledge about an unusual and little-studied group of microbes, bringing together information that has hitherto been widely scattered throughout the scientific literature. The sulphate-reducing bacteria cannot grow in air; they respire sulphates instead of oxygen and are difficult to isolate and study. Nevertheless, much progress has been made in recent years and has revealed novelties of biochemistry and physiology. Sulphate-reducing bacteria affect man in a variety of subtle and occasionally blatant ways although, unlike many bacteria, they cause no disease. Among harmful attributes are being agents of pollution, corrosion and spoilage of food and materials. Their beneficial attributes include the generation of most of the world's sulphur supplies and several other mineral resources, as well as contributing to the oil reserves of this planet. They grow in oil wells, sulphur springs, natural gas stores, sewage sludge and comparable habitats. They are not only of great academic interest but also of increasing practical importance in oil, gas, mineral and corrosion technology.

  19. Multiple stage multiple filter hydrate store

    DOEpatents

    Bjorkman, Jr., Harry K.

    1983-05-31

    An improved hydrate store for a metal halogen battery system is disclosed which employs a multiple stage, multiple filter means or separating the halogen hydrate from the liquid used in forming the hydrate. The filter means is constructed in the form of three separate sections which combine to substantially cover the interior surface of the store container. Exit conduit means is provided in association with the filter means for transmitting liquid passing through the filter means to a hydrate former subsystem. The hydrate former subsystem combines the halogen gas generated during the charging of the battery system with the liquid to form the hydrate in association with the store. Relief valve means is interposed in the exit conduit means for controlling the operation of the separate sections of the filter means, such that the liquid flow through the exit conduit means from each of the separate sections is controlled in a predetermined sequence. The three separate sections of the filter means operate in three discrete stages to provide a substantially uniform liquid flow to the hydrate former subsystem during the charging of the battery system. The separation of the liquid from the hydrate causes an increase in the density of the hydrate by concentrating the hydrate along the filter means.

  20. Multiple stage multiple filter hydrate store

    DOEpatents

    Bjorkman, H.K. Jr.

    1983-05-31

    An improved hydrate store for a metal halogen battery system is disclosed which employs a multiple stage, multiple filter means for separating the halogen hydrate from the liquid used in forming the hydrate. The filter means is constructed in the form of three separate sections which combine to substantially cover the interior surface of the store container. Exit conduit means is provided in association with the filter means for transmitting liquid passing through the filter means to a hydrate former subsystem. The hydrate former subsystem combines the halogen gas generated during the charging of the battery system with the liquid to form the hydrate in association with the store. Relief valve means is interposed in the exit conduit means for controlling the operation of the separate sections of the filter means, such that the liquid flow through the exit conduit means from each of the separate sections is controlled in a predetermined sequence. The three separate sections of the filter means operate in three discrete stages to provide a substantially uniform liquid flow to the hydrate former subsystem during the charging of the battery system. The separation of the liquid from the hydrate causes an increase in the density of the hydrate by concentrating the hydrate along the filter means. 7 figs.

  1. Hydrate habitat

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Whoever said there is nothing new under the sun did not delve deeply enough to the bottom of the ocean. There in the Gulf of Mexico, about 150 miles south of New Orleans, scientists have just discovered what could be a new species of centipede—like worms living on or within gas hydrates— mounds of methane ice— rising from the ocean floor.Scientists have previously recognized an association between some bacteria and these hydrates. However, this is the first discovery of a higher life form there.

  2. The influence of hydrogen bonding on the dielectric constant and the piezoelectric energy harvesting performance of hydrated metal salt mediated PVDF films.

    PubMed

    Jana, Santanu; Garain, Samiran; Sen, Shrabanee; Mandal, Dipankar

    2015-07-14

    Polyvinylidene fluoride (PVDF) films are filled with various mass fractions (wt%) of hydrated metal salt (MgCl2·6H2O) (Mg-salt) to fabricate high performance piezoelectric energy harvesters (PEHs). They deliver up to 4 V of open circuit voltage by simply repeated human finger imparting (under a pressure of ∼4.45 kPa) and also generate sufficient power to turn on at least ten commercial blue light emitting diodes (LEDs) instantly. The enhanced piezo-response is attributed to the combined effect of the change in the inherent dipole moment of the electroactive phase containing PVDF itself and H-bonding arising between the Mg-salt filler and PVDF via electrostatic interactions. Furthermore, it also successfully charged the capacitors, signifying practical applicability as a piezoelectric based energy harvester power source. UV-visible optical absorption spectral analysis revealed the possibility to estimate a change in the optical band gap value at different concentrations of Mg-salt filler added PVDF films that possess a useful methodology where the Mg-salt can be used as an optical probe. In addition dielectric properties have been studied to understand the role of molecular kinetic and interfacial polarization occurs in H-bond PVDF films at different applied frequencies at room temperature.

  3. Influence of the hydration by the environmental humidity on the metallic speciation and the photocatalytic activity of Cr/MCM-41

    SciTech Connect

    Elías, Verónica R.; Sabre, Ema V.; Winkler, Elin L.; Andrini, Leandro; Requejo, Félix G.; Casuscelli, Sandra G.; Eimer, Griselda A.

    2014-05-01

    The influence of the environmental humidity on the Cr species deposited on inorganic supports like MCM-41 silicates was analyzed by UV–vis Diffuse Reflectance (UV–vis RD), Electronic Spin Resonance (ESR) and X-ray near-edge (XANES) spectroscopy. Metal speciation could be inferred, finding that prolonged exposure periods under environmental humidity provoked the reduction of the active Cr{sup 6+} species and thus, the decrease of the Cr/MCM-41 photoactivity. After the Ti loading over the Cr modified samples, Cr species and the photoactivity were not notably influenced by the humidity exposure. Thus, it could be concluded that the presence of Ti is important because the TiO{sub 2} cover protects the oxidized Cr species, stabilizing them. - Graphical abstract: The load of Ti on the Cr modified MCM-41 produces a TiO{sub 2} cover that protects the active Cr species from their reduction by the environmental humidity. - Highlights: • Spectroscopic analysis shows presence of Cr{sup 6+}/Cr{sup 5+} in calcined/re-calcined samples. • Cr{sup 3+} species increase for hydrated samples causing their photoactivity decrease. • Samples with high Cr loadings are more sensitive to environmental humidity presence. • TiO{sub 2} cover protects oxidized Cr species from their reduction by the water. • Ti is important to allow a synergistic effect and to stabilize active Cr{sup 6+}/Cr{sup 5+}.

  4. The influence of hydrogen bonding on the dielectric constant and the piezoelectric energy harvesting performance of hydrated metal salt mediated PVDF films.

    PubMed

    Jana, Santanu; Garain, Samiran; Sen, Shrabanee; Mandal, Dipankar

    2015-07-14

    Polyvinylidene fluoride (PVDF) films are filled with various mass fractions (wt%) of hydrated metal salt (MgCl2·6H2O) (Mg-salt) to fabricate high performance piezoelectric energy harvesters (PEHs). They deliver up to 4 V of open circuit voltage by simply repeated human finger imparting (under a pressure of ∼4.45 kPa) and also generate sufficient power to turn on at least ten commercial blue light emitting diodes (LEDs) instantly. The enhanced piezo-response is attributed to the combined effect of the change in the inherent dipole moment of the electroactive phase containing PVDF itself and H-bonding arising between the Mg-salt filler and PVDF via electrostatic interactions. Furthermore, it also successfully charged the capacitors, signifying practical applicability as a piezoelectric based energy harvester power source. UV-visible optical absorption spectral analysis revealed the possibility to estimate a change in the optical band gap value at different concentrations of Mg-salt filler added PVDF films that possess a useful methodology where the Mg-salt can be used as an optical probe. In addition dielectric properties have been studied to understand the role of molecular kinetic and interfacial polarization occurs in H-bond PVDF films at different applied frequencies at room temperature. PMID:26077827

  5. Sulphate, more than a nutrient, protects the microalga Chlamydomonas moewusii from cadmium toxicity.

    PubMed

    Mera, Roi; Torres, Enrique; Abalde, Julio

    2014-03-01

    Sulphur is an essential macroelement that plays important roles in living organisms. The thiol rich sulphur compounds, such as cysteine, γ-Glu-Cys, glutathione and phytochelatins participate in the tolerance mechanisms against cadmium toxicity. Plants, algae, yeasts and most prokaryotes cover their demand for reduced sulphur by reduction of inorganic sulphate. The aim of this study was to investigate, using a bifactorial experimental design, the effect of different sulphate concentrations in the nutrient solution on cadmium toxicity in the freshwater microalga Chlamydomonas moewusii. Cell growth, kinetic parameters of sulphate utilization and intracellular concentrations of low-molecular mass thiol compounds were determined. A mathematical model to describe the growth of this microalga based on the effects of sulphate and cadmium was obtained. An ANOVA revealed an interaction between them, 16% of the effect sizes was explained by this interaction. A higher amount of sulphate in the culture medium allowed a higher cadmium tolerance due to an increase in the thiol compound biosynthesis. The amount of low-molecular mass thiol compounds, mainly phytochelatins, synthesized by this microalga was significantly dependent on the sulphate and cadmium concentrations; the higher phytochelatin content was obtained in cultures with 4 mg Cd/L and 1mM sulphate. The maximum EC50 value (based on nominal cadmium concentration) reached for this microalga was 4.46 ± 0.42 mg Cd/L when the sulphate concentration added to the culture medium was also 1mM. An increase in the sulphate concentration, in deficient environments, could alleviate the toxic effect of this metal; however, a relative excess is also negative. The results obtained showed a substrate inhibition for this nutrient. An uncompetitive model for sulphate was chosen to establish the mathematical model that links both factors.

  6. 7 CFR 160.10 - Sulphate wood turpentine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or...

  7. 7 CFR 160.10 - Sulphate wood turpentine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or...

  8. 7 CFR 160.10 - Sulphate wood turpentine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or...

  9. 7 CFR 160.10 - Sulphate wood turpentine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or...

  10. 7 CFR 160.10 - Sulphate wood turpentine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Sulphate wood turpentine. 160.10 Section 160.10... STANDARDS FOR NAVAL STORES General § 160.10 Sulphate wood turpentine. The designation “sulphate wood... in the sulphate process of cooking wood pulp, and commonly known as sulphate turpentine or...

  11. Ferrous sulphate interacts with captopril

    PubMed Central

    Schaefer, J P; Tam, Y; Hasinoff, B B; Tawfik, S; Peng, Y; Reimche, L; Campbell, N R C

    1998-01-01

    Aims To determine if iron binds strongly to captopril and reduces captopril absorption. Methods A variety of in vitro experiments was conducted to examine iron binding to captopril and a randomized, double-blind, placebo controlled, cross-over study design was used to assess the in vivo interaction. Captopril (25 mg) was coingested with either ferrous sulphate (300 mg) or placebo by seven healthy adult volunteers. Subjects were phlebotomized and had blood pressure measured at 0, 0.25, 0.5, 1, 2, 4, 6, 8, and 12 h post ingestion. A 1 week washout period was used. Results The coingestion of ferrous sulphate and captopril was associated with a 37% (134 ng ml−1 h, 95% CI 41–228 ng ml−1 h, P=0.03) decrease in area under the curve (AUC) for unconjugated plasma captopril. There were no substantial changes in Cmax (mean difference;–32; 95% CI −124–62 ng ml−1(P=0.57)) or in tmax (mean difference; 0; 95% CI −18–18 min (P=0.65)) for unconjugated captopril when captopril was ingested with iron. There was a statistically insignificant increase in AUC for total plasma captopril of 43% (1312 ng ml−1 h, 95% CI −827–3451 ng ml−1 h P=0.27) when captopril was ingested with iron. The addition of ferric chloride to captopril resulted in the initial rapid formation of a soluble blue complex which rapidly disappeared to be replaced by a white precipitant. The white precipitate was identified as captopril disulphide dimer. There were no significant differences in systolic and diastolic blood pressures between the treatment and placebo groups. Conclusions Co-administration of ferrous sulphate and iron results in decreased unconjugated captopril levels likely due to a chemical interaction between ferric ion and captopril in the gastrointestinal tract. Care is required when coprescribing captopril and iron salts. PMID:9803987

  12. Dehydration of plutonium or neptunium trichloride hydrate

    DOEpatents

    Foropoulos, Jr., Jerry; Avens, Larry R.; Trujillo, Eddie A.

    1992-01-01

    A process of preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride is provided.

  13. Dehydration of plutonium or neptunium trichloride hydrate

    DOEpatents

    Foropoulos, J. Jr.; Avens, L.R.; Trujillo, E.A.

    1992-03-24

    A process is described for preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride.

  14. Vibrational spectroscopic study of sulphated silk proteins

    NASA Astrophysics Data System (ADS)

    Monti, P.; Freddi, G.; Arosio, C.; Tsukada, M.; Arai, T.; Taddei, P.

    2007-05-01

    Degummed Bombyx mori ( B. m.) silk fibroin fabric and mutant naked pupa cocoons (Nd-s) consisting of almost pure silk sericin were treated with chlorosulphonic acid in pyridine and investigated by FT-IR and FT-Raman spectroscopies. Untreated silk fibroin and sericin displayed typical spectral features due to characteristic amino acid composition and molecular conformation (prevailing β-sheet with a less ordered structure in sericin). Upon sulphation, the degree of molecular disorder increased in both proteins and new bands appeared. The IR bands at 1049 and 1014 cm -1 were attributed to vibrations of sulphate salts and that at 1385 cm -1 to the νasSO 2 mode of organic covalent sulphates. In the 1300-1180 cm -1 range various contributions of alkyl and aryl sulphate salts, sulphonamides, sulphoamines and organic covalent sulphates, fell. Fibroin covalently bound sulphate groups through the hydroxyl groups of tyrosine and serine, while sericin through the hydroxyl groups of serine, since the δOH vibrations at 1399 cm -1 in IR and at 1408 cm -1 in Raman disappeared almost completely. Finally, the increase of the I850/ I830 intensity ratio of Raman tyrosine doublet in fibroin suggested a change towards a more exposed state of tyrosine residues, in good agreement with the more disordered conformation taken upon sulphation.

  15. Anaerobic pond treatment of wastewater containing sulphate.

    PubMed

    Rajbhandari, B K; Annachhatre, A P

    2007-01-01

    Anaerobic ponds are usually used for treatment of industrial and agricultural wastes which contain high organic matter and sulphate. Competition for substrate between sulphate reducing bacteria and methane producing archaea, and the inhibitory effects of sulphide produced from microbial sulphate reduction reported in the literature varied considerably. In this research, a laboratory scale column-in-series anaerobic pond reactor, consisting of five cylindrical columns of acrylic tubes, was operated to evaluate the effect of COD and sulphate ratio on pond performance treating wastewater containing high organic matter and sulphate from a tapioca starch industry. The result depicted that no adverse effect of COD:SO4 ratios between 5 and 20 on overall COD removal performance of anaerobic pond operated with organic loading rate (OLR) of 150 to 600 g COD/m3d. Sulphate reducing bacteria could out-compete methane producing archaea for the same substrate at COD:SO4 ratio equal to or lower than 5 and OLR greater than 300 g COD/m3d. Sulphide inhibition was not observed on overall performance of pond up to an influent sulphate concentration of 650 mg/L.

  16. Vibrational spectroscopy of the sulphate mineral sturmanite from Kuruman manganese deposits, South Africa.

    PubMed

    Frost, Ray L; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Lana, Cristiano

    2014-12-10

    The mineral sturmanite is a hydrated calcium iron aluminium manganese sulphate tetrahydroxoborate hydroxide of formula Ca6(Fe, Al, Mn)2(SO4)2(B(OH)4)(OH)12·26H2O. We have studied the mineral sturmanite using a number of techniques, including SEM with EPMA and vibrational spectroscopy. Chemical analysis shows a homogeneous phase, composed by Ca, Fe, Mn, S, Al and Si. B is not determined in this EPMA technique. An intense Raman band at 990cm(-1) is assigned to the SO4(2-) symmetric stretching mode. Raman spectroscopy identifies multiple sulphate symmetric stretching modes in line with the three sulphate crystallographically different sites. Raman spectroscopy also identifies a band at 1069cm(-1) which may be attributed to a carbonate symmetric stretching mode, indicating the presence of thaumasite. Infrared spectra display two bands at 1080 and 1107cm(-1) assigned to the SO4(2-) antisymmetric stretching modes. The observation of multiple bands in this ν4 spectral region offers evidence for the reduction in symmetry of the sulphate anion from Td to C2v or even lower symmetry. The Raman band at 3622cm(-1) is assigned to the OH unit stretching vibration and the broad feature at around 3479cm(-1) to water stretching bands. Infrared spectroscopy shows a set of broad overlapping bands in the OH stretching region. Vibrational spectroscopy enables an assessment of the molecular structure of sturmanite to be made.

  17. Vibrational spectroscopy of the sulphate mineral sturmanite from Kuruman manganese deposits, South Africa

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Lana, Cristiano

    2014-12-01

    The mineral sturmanite is a hydrated calcium iron aluminium manganese sulphate tetrahydroxoborate hydroxide of formula Ca6(Fe, Al, Mn)2(SO4)2(B(OH)4)(OH)12·26H2O. We have studied the mineral sturmanite using a number of techniques, including SEM with EPMA and vibrational spectroscopy. Chemical analysis shows a homogeneous phase, composed by Ca, Fe, Mn, S, Al and Si. B is not determined in this EPMA technique. An intense Raman band at 990 cm-1 is assigned to the SO42- symmetric stretching mode. Raman spectroscopy identifies multiple sulphate symmetric stretching modes in line with the three sulphate crystallographically different sites. Raman spectroscopy also identifies a band at 1069 cm-1 which may be attributed to a carbonate symmetric stretching mode, indicating the presence of thaumasite. Infrared spectra display two bands at 1080 and 1107 cm-1 assigned to the SO42- antisymmetric stretching modes. The observation of multiple bands in this ν4 spectral region offers evidence for the reduction in symmetry of the sulphate anion from Td to C2v or even lower symmetry. The Raman band at 3622 cm-1 is assigned to the OH unit stretching vibration and the broad feature at around 3479 cm-1 to water stretching bands. Infrared spectroscopy shows a set of broad overlapping bands in the OH stretching region. Vibrational spectroscopy enables an assessment of the molecular structure of sturmanite to be made.

  18. Vibrational spectroscopy of the sulphate mineral sturmanite from Kuruman manganese deposits, South Africa.

    PubMed

    Frost, Ray L; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Lana, Cristiano

    2014-12-10

    The mineral sturmanite is a hydrated calcium iron aluminium manganese sulphate tetrahydroxoborate hydroxide of formula Ca6(Fe, Al, Mn)2(SO4)2(B(OH)4)(OH)12·26H2O. We have studied the mineral sturmanite using a number of techniques, including SEM with EPMA and vibrational spectroscopy. Chemical analysis shows a homogeneous phase, composed by Ca, Fe, Mn, S, Al and Si. B is not determined in this EPMA technique. An intense Raman band at 990cm(-1) is assigned to the SO4(2-) symmetric stretching mode. Raman spectroscopy identifies multiple sulphate symmetric stretching modes in line with the three sulphate crystallographically different sites. Raman spectroscopy also identifies a band at 1069cm(-1) which may be attributed to a carbonate symmetric stretching mode, indicating the presence of thaumasite. Infrared spectra display two bands at 1080 and 1107cm(-1) assigned to the SO4(2-) antisymmetric stretching modes. The observation of multiple bands in this ν4 spectral region offers evidence for the reduction in symmetry of the sulphate anion from Td to C2v or even lower symmetry. The Raman band at 3622cm(-1) is assigned to the OH unit stretching vibration and the broad feature at around 3479cm(-1) to water stretching bands. Infrared spectroscopy shows a set of broad overlapping bands in the OH stretching region. Vibrational spectroscopy enables an assessment of the molecular structure of sturmanite to be made. PMID:24929311

  19. Gas hydrate and humans

    USGS Publications Warehouse

    Kvenvolden, K.A.

    2000-01-01

    The potential effects of naturally occurring gas hydrate on humans are not understood with certainty, but enough information has been acquired over the past 30 years to make preliminary assessments possible. Three major issues are gas hydrate as (1) a potential energy resource, (2) a factor in global climate change, and (3) a submarine geohazard. The methane content is estimated to be between 1015 to 1017 m3 at STP and the worldwide distribution in outer continental margins of oceans and in polar regions are significant features of gas hydrate. However, its immediate development as an energy resource is not likely because there are various geological constraints and difficult technological problems that must be solved before economic recovery of methane from hydrate can be achieved. The role of gas hydrate in global climate change is uncertain. For hydrate methane to be an effective greenhouse gas, it must reach the atmosphere. Yet there are many obstacles to the transfer of methane from hydrate to the atmosphere. Rates of gas hydrate dissociation and the integrated rates of release and destruction of the methane in the geo/hydro/atmosphere are not adequately understood. Gas hydrate as a submarine geohazard, however, is of immediate and increasing importance to humans as our industrial society moves to exploit seabed resources at ever-greater depths in the waters of our coastal oceans. Human activities and installations in regions of gas-hydrate occurrence must take into account the presence of gas hydrate and deal with the consequences of its presence.

  20. Experimental study of the replacement of calcite by calcium sulphates

    NASA Astrophysics Data System (ADS)

    Ruiz-Agudo, E.; Putnis, C. V.; Hövelmann, J.; Álvarez-Lloret, P.; Ibáñez-Velasco, A.; Putnis, A.

    2015-05-01

    Among the most relevant mineral replacement reactions are those involving sulphates and carbonates, which have important geological and technological implications. Here it is shown experimentally that during the interaction of calcite (CaCO3) cleavage surfaces with sulphate-bearing acidic solutions, calcite is ultimately replaced by gypsum (CaSO4 2H2O) and anhydrite (CaSO4), depending on the reaction temperature. Observations suggest that this occurs most likely via an interface-coupled dissolution-precipitation reaction, in which the substrate is replaced pseudomorphically by the product. At 120 and 200 °C gypsum and/or bassanite (CaSO4·0.5H2O) form as precursor phases for the thermodynamically stable anhydrite. Salinity promotes the formation of less hydrated precursor phases during the replacement of calcite by anhydrite. The reaction stops before equilibrium with respect to calcite is reached and during the course of the reaction most of the bulk solutions are undersaturated with respect to the precipitating phase(s). A mechanism consisting of the dissolution of small amounts of solid in a thin layer of fluid at the mineral-fluid interface and the subsequent precipitation of the product phase from this layer is in agreement with these observations. PHREEQC simulations performed in the framework of this mechanism highlight the relevance of transport and surface reaction kinetics on the volume change associated with the CaCO3-CaSO4 replacement. Under our experimental conditions, this reaction occurs with a positive volume change, which ultimately results in passivation of the unreacted substrate before calcite attains equilibrium with respect to the bulk solution.

  1. Zinc sulphate and vitamin E alleviate reproductive toxicity caused by aluminium sulphate in male albino rats.

    PubMed

    Rawi, Sayed M; Seif Al Nassr, Fatma M

    2015-03-01

    This study was designed to investigate the reproductive toxicity of aluminium sulphate and the therapeutic effects of administration of zinc sulphate and vitamin E individually or in combination against the toxic effect caused by aluminium (Al) in male albino rats. The animals were divided into five groups: group 1 received distilled water and served as control; group 2 received only aluminium sulphate (50 mg/kg body weight (b.w.)); group 3 received aluminium sulphate (50 mg/kg b.w.) plus zinc sulphate (50 mg/kg b.w.); group 4 received aluminium sulphate (50 mg/kg b.w.) and vitamin E (15 mg/kg b.w.); group 5 received aluminium sulphate plus a combination of zinc sulphate and vitamin E in similar doses as above. Doses were administered orally once daily for 45 consecutive days. The results revealed that aluminium sulphate induced significant decrease in body weight gain and testis weight and significant increase in Al level in both serum and testes of male rats. Biochemical analysis showed significant decrease in serum total protein and phospholipids levels, while serum total lipid was significantly elevated post Al treatment. In addition, significant decrease in total protein, phospholipids and cholesterol levels in the testes of Al-treated rats was recorded. The data also showed significant decrease in the levels of serum testosterone, leutinizing hormone and follicle stimulating hormone and significant increase in the level of serum prolactin in Al-intoxicated rats. Moreover, histological examination showed that aluminium sulphate caused apparent alterations in the testicular structure of the treated animals. Treatment with zinc sulphate and vitamin E individually or in combination ameliorated the harmful effects of Al, which was proved histopathologically by the noticeable improvement in the testicular tissues. We can conclude that the tested dose of aluminium sulphate induced toxic effect on the reproductive system of male albino rats and the treatment with

  2. Sulphate-activated growth of bamboo-like carbon nanotubes over copper catalysts

    NASA Astrophysics Data System (ADS)

    Lin, Jarrn-Horng; Chen, Ching-Shiun; Zeng, Zhi-Yan; Chang, Chia-Wei; Chen, Hsiu-Wei

    2012-07-01

    A sulphate-activated mechanism is proposed to describe the growth of bamboo-like carbon nanotubes (CNTs) over copper catalysts using chemical vapour deposition with helium-diluted ethylene. Sulphate-assisted copper catalysts afford a high-yield growth of bamboo-like CNTs at a mild temperature, 800 °C however, non-sulphate-assisted copper catalysts, e.g., copper acetate and copper nitrate prepared catalysts, were inert to CNT growth and only gave amorphous carbons (a-C) surrounding copper nanoparticles under the same conditions. Nevertheless, the addition of sulphate ions in the preparation step for the two inert catalysts can activate their abilities for CNT growth with remarkable yields. Furthermore, Raman spectra analysis demonstrates a linear dependence between the concentration of sulphate ions in copper catalysts and the ratio of CNT-a-C in the as-grown carbon soot. The sulphate-activated effect on CNT growth over copper catalysts could be related to a three-way interaction of sulphate ions, copper nanoparticles and support. In situ TEM images of an as-grown CNT irradiated by electron beams without the inlet of carbon sources reveal a new pathway of carbon diffusion through the bulk of copper nanoparticles and an enlarged inner-wall thickness of the on-site CNT. This carbon diffusion model over copper catalysts can provide new insights into the CNT growth mechanism over non-magnetic metal catalysts.A sulphate-activated mechanism is proposed to describe the growth of bamboo-like carbon nanotubes (CNTs) over copper catalysts using chemical vapour deposition with helium-diluted ethylene. Sulphate-assisted copper catalysts afford a high-yield growth of bamboo-like CNTs at a mild temperature, 800 °C however, non-sulphate-assisted copper catalysts, e.g., copper acetate and copper nitrate prepared catalysts, were inert to CNT growth and only gave amorphous carbons (a-C) surrounding copper nanoparticles under the same conditions. Nevertheless, the addition of

  3. Biological treatment of acidic coal refuse using sulphate-reducing bacteria with chicken manure as carbon source.

    PubMed

    Zhang, Mingliang; Wang, Haixia

    2014-01-01

    The performance of using chicken manure as carbon source to promote sulphate-reducing bacteria (SRB) activity within acidic coal refuse to prevent the generation of acidic leachate was investigated in batch and column bioreactors. The bioreactors showed satisfactory performance in biological sulphate reduction, evidenced by the increase in effluent pH, high removal efficiencies of sulphate and metals, and the presence of large numbers of SRB. Scanning electron microscope-energy dispersive spectrometry (EDS) analysis of the formed precipitate indicated the formation of metal sulphides. Chicken manure was observed to play an important role in this treatment, which could not only provide carbon source but also reduce the adverse effect of strong acidity and metal toxicity on SRB activity. Metal removal could be mainly attributed to sulphides precipitation and sorption to chicken manure. This study indicated that SRB with chicken manure could be a novel alternative used for the prevention of acidic leachate from coal refuse.

  4. Histopathological and microanalytical study of zirconium dioxide and barium sulphate in bone cement.

    PubMed Central

    Keen, C. E.; Philip, G.; Brady, K.; Spencer, J. D.; Levison, D. A.

    1992-01-01

    AIMS: To report the appearances of zirconium dioxide and barium sulphate in interface membranes, synovium, and other tissues around joint prostheses. METHODS: Histological sections from 23 specimens were reviewed by light microscopy and polarisation. Scanning electron microscopy and x ray microanalysis were performed on routinely processed paraffin wax sections. RESULTS: Polyethylene, metals, and polymethylmethacrylate cement debris were easily recognisable. Almost all the cement remnants contained either zirconium dioxide or barium sulphate, confirmed by microanalysis. The contrast media had characteristic light microscopic appearances. Zirconium was identified in macrophages away from cement remnants. CONCLUSION: The presence of radiographic contrast media in tissues around prosthetic joints is common but not widely recognised. Images PMID:1452794

  5. Origins of hydration lubrication.

    PubMed

    Ma, Liran; Gaisinskaya-Kipnis, Anastasia; Kampf, Nir; Klein, Jacob

    2015-01-14

    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4-1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication.

  6. Method for the photocatalytic conversion of gas hydrates

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.; Bockrath, Bradley C.

    2001-01-01

    A method for converting methane hydrates to methanol, as well as hydrogen, through exposure to light. The process includes conversion of methane hydrates by light where a radical initiator has been added, and may be modified to include the conversion of methane hydrates with light where a photocatalyst doped by a suitable metal and an electron transfer agent to produce methanol and hydrogen. The present invention operates at temperatures below 0.degree. C., and allows for the direct conversion of methane contained within the hydrate in situ.

  7. Influence of respiratory substrate in carbon steel corrosion by a Sulphate Reducing Prokaryote model organism.

    PubMed

    Dall'agnol, Leonardo T; Cordas, Cristina M; Moura, José J G

    2014-06-01

    Sulphate Reducing Prokaryotes (SRP) are an important group of microorganisms involved in biocorrosion processes. Sulphide production is recognized as a fundamental cause of corrosion and nitrate is often used as treatment. The present work analyses the influence of respiratory substrates in the metal, from off-shore installations, SRP influenced corrosion, using Desulfovibrio desulfuricans ATTC 27774 as model organism, since this can switch from sulphate to nitrate. Open Circuit Potential over 6days in different conditions was measured, showing an increase around 200 and 90mV for the different media. Tafel plots were constructed allowing Ecorr and jcorr calculations. For SRP in sulphate and nitrate media Ecorr values of -824 and -728mV, and jcorr values of 2.5 and 3.7μAcm(-2), respectively, were attained indicating that in nitrate, the resultant corrosion rate is larger than in sulphate. Also, it is shown that the equilibrium of sulphide in the solution/gas phases is a key factor to the evolution of corrosion Nitrate prevents pitting but promotes general corrosion and increases the corrosion potential and iron dissolution 40 times when compared to sulphate. Our results demonstrate that nitrate injection strategy in oil fields has to be considered carefully as option to reduce souring and localized corrosion.

  8. Asymmetric Membrane Osmotic Capsules for Terbutaline Sulphate

    PubMed Central

    Gobade, N. G.; Koland, Marina; Harish, K. H.

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate. PMID:23204625

  9. Asymmetric membrane osmotic capsules for terbutaline sulphate.

    PubMed

    Gobade, N G; Koland, Marina; Harish, K H

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate. PMID:23204625

  10. Differential expression of specific sulphate transporters underlies seasonal and spatial patterns of sulphate allocation in trees.

    PubMed

    Malcheska, F; Honsel, A; Wildhagen, H; Dürr, J; Larisch, C; Rennenberg, H; Herschbach, C

    2013-07-01

    Sulphate uptake and its distribution within plants depend on the activity of different sulphate transporters (SULTR). In long-living deciduous plants such as trees, seasonal changes of spatial patterns add another layer of complexity to the question of how the interplay of different transporters adjusts S distribution within the plant to environmental changes. Poplar is an excellent model to address this question because its S metabolism is already well characterized. In the present study, the importance of SULTRs for seasonal sulphate storage and mobilization was examined in the wood of poplar (Populus tremula × P. alba) by analysing their gene expression in relation to sulphate contents in wood and xylem sap. According to these results, possible functions of the respective SULTRs for seasonal sulphate storage and mobilization in the wood are suggested. Together, the present results complement the previously published model for seasonal sulphate circulation between leaves and bark and provide information for future mechanistic modelling of whole tree sulphate fluxes. PMID:23278135

  11. Effect of aluminium sulphate on interactions between silica surfaces studied by atomic force microscopy.

    PubMed

    Donose, Bogdan C; Nguyen, Anh V; Evans, Geoffrey M; Yan, Yaode

    2007-08-01

    Surface interaction forces between different types of silica surfaces (pure silica beads, borosilicate glass beads, polished silicon wafers and fused silica slides) were measured by atomic force microscopy (AFM) in solutions of aluminium sulphate (alum) in order to understand the role of hydrated aluminium species on the coagulation of negatively charged oxide colloids in drinking water treatment. The alum coagulant concentration used in this study was 150 microM aluminium. The alum solutions were prepared from analytical grade Al2(SO4)3.16H2O. It was found that the presence of aluminium sulphate at a concentration close to the values typically used in industrial scale water treatment applications generally induced strong, long-range repulsive forces between the various types of surfaces studied. At this alum concentration streaming potential measurements indicated reversal in the sign of the surface charge. It was also found that whenever borosilicate glass beads were used, the interaction force became strongly attractive when the AFM cell was flushed with deionised water. It was argued that this attraction occurred because of the charge nonuniformity of the aluminium hydrates adsorbed at the glass surface. A mechanism was proposed to explain the observed interaction phenomena based on the deduced microstructure of the adsorbed surface layers and to rationalise the new findings for applications in drinking water treatment.

  12. The impact of sulphate and magnesium on chloride binding in Portland cement paste

    SciTech Connect

    De Weerdt, K.; Orsáková, D.; Geiker, M.R.

    2014-11-15

    The effect of magnesium and sulphate present in sea water on chloride binding in Portland cement paste was investigated. Ground well hydrated cement paste was exposed to MgCl{sub 2}, NaCl, NaCl + MgCl{sub 2}, MgSO{sub 4} + MgCl{sub 2} and artificial sea water solutions with a range of concentrations at 20 °C. Chloride binding isotherms are determined and pH of the solutions were measured. A selection of samples was examined by SEM-EDS to identify phase changes upon exposure. The experimental data were compared with calculations of a thermodynamic model. Chloride binding from sea water was similar to chloride binding for NaCl solutions. The magnesium content in the sea water lead to a slight decrease in pH, but this did not result in a notable increase in chloride binding. The sulphate present in sea water reduces both chloride binding in C–S–H and AFm phases, as the C–S–H incorporates more sulphates instead of chlorides, and part of the AFm phases converts to ettringite.

  13. TOUGH-Fx/Hydrate

    SciTech Connect

    Moridis, George Julius

    2005-02-01

    TOUGH-Fx/HYORATL can model the non-isothermal gas release. phase behavior and flow of fluids and heat in complex geologic media. The code can simulate production from natural gas hydrate deposits in the subsurtace (i.e., in the permafrost and in deep ocean sediments), as well as laboratory experiments of hydrate dissociation/formation in porous/fractured media. T006H-Fx/HYDRATE vi .0 includes both an equilibrium and a kinetic model of hydrate Ibmiation and dissociation. The model accounts for heat and up to four mass components-- i.e., water, CH4, hydrate, and water-soluble inhibitors such as salts or alcohols. These are partitioned among four possible phases (gas phase, liquid phase, ice phase and hydrate phase). Hydrate dIssociation or formation, phase changes, and the corresponding thermal effects are fully described, as are the effects of inhibitors. The model can describe all possible hydrate dissociation mechanisms, i.e., depressurization, thermal stimulation, salting-out effects, and inhibItor-Induced effects.

  14. TOUGH-Fx/Hydrate

    2005-02-01

    TOUGH-Fx/HYORATL can model the non-isothermal gas release. phase behavior and flow of fluids and heat in complex geologic media. The code can simulate production from natural gas hydrate deposits in the subsurtace (i.e., in the permafrost and in deep ocean sediments), as well as laboratory experiments of hydrate dissociation/formation in porous/fractured media. T006H-Fx/HYDRATE vi .0 includes both an equilibrium and a kinetic model of hydrate Ibmiation and dissociation. The model accounts for heat and upmore » to four mass components-- i.e., water, CH4, hydrate, and water-soluble inhibitors such as salts or alcohols. These are partitioned among four possible phases (gas phase, liquid phase, ice phase and hydrate phase). Hydrate dIssociation or formation, phase changes, and the corresponding thermal effects are fully described, as are the effects of inhibitors. The model can describe all possible hydrate dissociation mechanisms, i.e., depressurization, thermal stimulation, salting-out effects, and inhibItor-Induced effects.« less

  15. Biopharmaceutical characterisation of ciprofloxacin-metallic ion interactions: comparative study into the effect of aluminium, calcium, zinc and iron on drug solubility and dissolution.

    PubMed

    Stojković, Aleksandra; Tajber, Lidia; Paluch, Krzysztof J; Djurić, Zorica; Parojčić, Jelena; Corrigan, Owen I

    2014-03-01

    Ciprofloxacin bioavailability may be reduced when ciprofloxacin is co-administered with metallic ion containing preparations. In our previous study, physicochemical interaction between ciprofloxacin and ferrous sulphate was successfully simulated in vitro. In the present work, comparative in vitro ciprofloxacin solubility and dissolution studies were performed in the reactive media containing aluminium hydroxide, calcium carbonate or zinc sulphate. Solid phases collected from the dissolution vessel with aluminium hydroxide, calcium carbonate and zinc sulphate were investigated for their properties. The results obtained indicate that different types of adducts may form and retard ciprofloxacin solubility and dissolution. In the case of aluminium, no phase changes were observed. The solid phase generated in the presence of calcium carbonate was identified as hydrated ciprofloxacin base. Similarly to iron, a new complex consistent with Zn(SO4)2(Cl)2(ciprofloxacin)2 × nH2O stoichiometry was generated in the presence of relatively high concentrations of ciprofloxacin hydrochloride and zinc sulphate, indicating that small volume dissolution experiments can be useful for biorelevant dissolution tests.

  16. The sulphate-reduction alkalinity pump tested

    NASA Astrophysics Data System (ADS)

    Meister, Patrick; Petrishcheva, Elena

    2016-04-01

    Carbonate precipitation has been suggested to be induced by alkalinity increase during sulphate reduction under anoxic conditions. This mechanism may explain the formation of carbonate deposits in shallow marine environments, either within a redox stratified sediment inhabited by phototrophic microbial mats or in shallow water within the photic zone where sulphidic water is upwelling onto the shelf. The alkalinity pump may work as long as the sulphide is not reoxidized to sulphate, a process that would acidify the surrounding. The alkalinity effect of sulphate reduction was recently tested by Aloisi (2008) for microbial mats using a model approach. He found that sulphate reduction does not significantly increase or even decrease carbonate saturation and is unlikely to have played a significant role through Earth history. The model considers many environmental factors, including the effect of carbonate precipitation itself on the carbonate equilbrium and on the alkalinity. We used a modified version of Aloisi's (2008) model to simulate the saturation states of aragonite, calcite and dolomite without the effects of carbonate precipitation. This is necessary to evaluate the effect of microbial metabolisms exclusively on carbonate saturation, since carbonate precipitation is only the consequence, but not the cause of oversaturation. First results show that the saturation state is increased in the zone of phototrophic CO2 uptake. In contrast, the saturation state is strongly decreased in the zone where dissolved oxygen overlaps with dissolved sulphide. Aerobic sulphide oxidation consumes most of the HS- and dissipates most of the alkalinity produced in the sulphate reduction zone below. Hence, our results are consistent with the findings of Aloisi (2008), and they even more clearly show that sulphate reduction does not induce carbonate precipitation nor contributes to carbonate precipitation in combination with phototrophic CO2 uptake. The alkalinity effect of sulphate

  17. Reinvestigation of growth of 'L-valine zinc sulphate' crystal.

    PubMed

    Srinivasan, Bikshandarkoil R; Jyai, Rita N

    2014-01-01

    A reinvestigation of the growth of l-valine zinc sulphate crystal is reported. The slow evaporation of an aqueous solution containing l-valine and zinc sulphate heptahydrate results in the fractional crystallization of l-valine and not the organic inorganic hybrid nonlinear optical l-valine zinc sulphate crystal, as reported by Puhal Raj and Ramachandra Raja (2012).

  18. Uncovering the Relationship between Sulphation Patterns and Conformation of Iduronic Acid in Heparan Sulphate

    NASA Astrophysics Data System (ADS)

    Hsieh, Po-Hung; Thieker, David F.; Guerrini, Marco; Woods, Robert J.; Liu, Jian

    2016-07-01

    The L-iduronic acid (IdoA) residue is a critically important structural component in heparan sulphate polysaccharide for the biological functions. The pyranose ring of IdoA is present in 1C4-chair, 2SO-skew boat, and less frequently, in 4C1-chair conformations. Here, we analyzed the conformation of IdoA residue in eight hexasaccharides by NMR. The data demonstrate a correlation between the conformation of IdoA and sulphations in the surrounding saccharide residues. For the 2-O-sulpho IdoA residue, a high degree of sulphation on neighboring residues drives ring dynamics towards the 2SO-skew boat conformer. In contrast, the nonsulphated IdoA residue is pushed towards the 1C4-chair conformer when the neighboring residues are highly sulphated. Our data suggest that the conformation of IdoA is regulated by the sulphation pattern of nearby saccharides that is genetically controlled by the heparan sulphate biosynthetic pathway.

  19. Uncovering the Relationship between Sulphation Patterns and Conformation of Iduronic Acid in Heparan Sulphate

    PubMed Central

    Hsieh, Po-Hung; Thieker, David F.; Guerrini, Marco; Woods, Robert J.; Liu, Jian

    2016-01-01

    The L-iduronic acid (IdoA) residue is a critically important structural component in heparan sulphate polysaccharide for the biological functions. The pyranose ring of IdoA is present in 1C4-chair, 2SO-skew boat, and less frequently, in 4C1-chair conformations. Here, we analyzed the conformation of IdoA residue in eight hexasaccharides by NMR. The data demonstrate a correlation between the conformation of IdoA and sulphations in the surrounding saccharide residues. For the 2-O-sulpho IdoA residue, a high degree of sulphation on neighboring residues drives ring dynamics towards the 2SO-skew boat conformer. In contrast, the nonsulphated IdoA residue is pushed towards the 1C4-chair conformer when the neighboring residues are highly sulphated. Our data suggest that the conformation of IdoA is regulated by the sulphation pattern of nearby saccharides that is genetically controlled by the heparan sulphate biosynthetic pathway. PMID:27412370

  20. Uncovering the Relationship between Sulphation Patterns and Conformation of Iduronic Acid in Heparan Sulphate.

    PubMed

    Hsieh, Po-Hung; Thieker, David F; Guerrini, Marco; Woods, Robert J; Liu, Jian

    2016-01-01

    The L-iduronic acid (IdoA) residue is a critically important structural component in heparan sulphate polysaccharide for the biological functions. The pyranose ring of IdoA is present in (1)C4-chair, (2)SO-skew boat, and less frequently, in (4)C1-chair conformations. Here, we analyzed the conformation of IdoA residue in eight hexasaccharides by NMR. The data demonstrate a correlation between the conformation of IdoA and sulphations in the surrounding saccharide residues. For the 2-O-sulpho IdoA residue, a high degree of sulphation on neighboring residues drives ring dynamics towards the (2)SO-skew boat conformer. In contrast, the nonsulphated IdoA residue is pushed towards the (1)C4-chair conformer when the neighboring residues are highly sulphated. Our data suggest that the conformation of IdoA is regulated by the sulphation pattern of nearby saccharides that is genetically controlled by the heparan sulphate biosynthetic pathway. PMID:27412370

  1. Correlation analysis between sulphate content and leaching of sulphates in recycled aggregates from construction and demolition wastes.

    PubMed

    Barbudo, Auxi; Galvín, Adela P; Agrela, Francisco; Ayuso, Jesús; Jiménez, Jose Ramón

    2012-06-01

    In some recycled aggregates applications, such as component of new concrete or roads, the total content of soluble sulphates should be measured and controlled. Restrictions are usually motivated by the resistance or stability of the new structure, and in most cases, structural concerns can be remedied by the use of techniques such as sulphur-resistant cements. However, environmental risk assessment from recycling and reuse construction products is often forgotten. The purpose of this study is to analyse the content of soluble sulphate on eleven recycled aggregates and six samples prepared in laboratory by the addition of different gypsum percentages. As points of reference, two natural aggregates were tested. An analysis of the content of the leachable amount of heavy metals regulated by European regulation was included. As a result, the correlation between solubility and leachability data allow suggest a limiting gypsum amount of 4.4% on recycled aggregates. This limit satisfies EU Landfill Directive criteria, which is currently used as reference by public Spanish Government for recycled aggregates in construction works. PMID:22410435

  2. Correlation analysis between sulphate content and leaching of sulphates in recycled aggregates from construction and demolition wastes.

    PubMed

    Barbudo, Auxi; Galvín, Adela P; Agrela, Francisco; Ayuso, Jesús; Jiménez, Jose Ramón

    2012-06-01

    In some recycled aggregates applications, such as component of new concrete or roads, the total content of soluble sulphates should be measured and controlled. Restrictions are usually motivated by the resistance or stability of the new structure, and in most cases, structural concerns can be remedied by the use of techniques such as sulphur-resistant cements. However, environmental risk assessment from recycling and reuse construction products is often forgotten. The purpose of this study is to analyse the content of soluble sulphate on eleven recycled aggregates and six samples prepared in laboratory by the addition of different gypsum percentages. As points of reference, two natural aggregates were tested. An analysis of the content of the leachable amount of heavy metals regulated by European regulation was included. As a result, the correlation between solubility and leachability data allow suggest a limiting gypsum amount of 4.4% on recycled aggregates. This limit satisfies EU Landfill Directive criteria, which is currently used as reference by public Spanish Government for recycled aggregates in construction works.

  3. Hydration rate of obsidian.

    PubMed

    Friedman, I; Long, W

    1976-01-30

    The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95 degrees to 245 degrees C. An expression relating hydration rate to temperature was derived for each sample. The SiO(2) content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents. With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates. If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to +/- 10 percent of the true age over periods as short as several years and as long as millions of years. PMID:17782901

  4. Hydration rate of obsidian.

    PubMed

    Friedman, I; Long, W

    1976-01-30

    The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95 degrees to 245 degrees C. An expression relating hydration rate to temperature was derived for each sample. The SiO(2) content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents. With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates. If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to +/- 10 percent of the true age over periods as short as several years and as long as millions of years.

  5. Methane Hydrates: Chapter 8

    USGS Publications Warehouse

    Boswell, Ray; Yamamoto, Koji; Lee, Sung-Rock; Collett, Timothy S.; Kumar, Pushpendra; Dallimore, Scott

    2008-01-01

    Gas hydrate is a solid, naturally occurring substance consisting predominantly of methane gas and water. Recent scientific drilling programs in Japan, Canada, the United States, Korea and India have demonstrated that gas hydrate occurs broadly and in a variety of forms in shallow sediments of the outer continental shelves and in Arctic regions. Field, laboratory and numerical modelling studies conducted to date indicate that gas can be extracted from gas hydrates with existing production technologies, particularly for those deposits in which the gas hydrate exists as pore-filling grains at high saturation in sand-rich reservoirs. A series of regional resource assessments indicate that substantial volumes of gas hydrate likely exist in sand-rich deposits. Recent field programs in Japan, Canada and in the United States have demonstrated the technical viability of methane extraction from gas-hydrate-bearing sand reservoirs and have investigated a range of potential production scenarios. At present, basic reservoir depressurisation shows the greatest promise and can be conducted using primarily standard industry equipment and procedures. Depressurisation is expected to be the foundation of future production systems; additional processes, such as thermal stimulation, mechanical stimulation and chemical injection, will likely also be integrated as dictated by local geological and other conditions. An innovative carbon dioxide and methane swapping technology is also being studied as a method to produce gas from select gas hydrate deposits. In addition, substantial additional volumes of gas hydrate have been found in dense arrays of grain-displacing veins and nodules in fine-grained, clay-dominated sediments; however, to date, no field tests, and very limited numerical modelling, have been conducted with regard to the production potential of such accumulations. Work remains to further refine: (1) the marine resource volumes within potential accumulations that can be

  6. Combustion of Methane Hydrate

    NASA Astrophysics Data System (ADS)

    Roshandell, Melika

    A significant methane storehouse is in the form of methane hydrates on the sea floor and in the arctic permafrost. Methane hydrates are ice-like structures composed of water cages housing a guest methane molecule. This caged methane represents a resource of energy and a potential source of strong greenhouse gas. Most research related to methane hydrates has been focused on their formation and dissociation because they can form solid plugs that complicate transport of oil and gas in pipelines. This dissertation explores the direct burning of these methane hydrates where heat from the combustion process dissociates the hydrate into water and methane, and the released methane fuels the methane/air diffusion flame heat source. In contrast to the pipeline applications, very little research has been done on the combustion and burning characteristics of methane hydrates. This is the first dissertation on this subject. In this study, energy release and combustion characteristics of methane hydrates were investigated both theoretically and experimentally. The experimental study involved collaboration with another research group, particularly in the creation of methane hydrate samples. The experiments were difficult because hydrates form at high pressure within a narrow temperature range. The process can be slow and the resulting hydrate can have somewhat variable properties (e.g., extent of clathration, shape, compactness). The experimental study examined broad characteristics of hydrate combustion, including flame appearance, burning time, conditions leading to flame extinguishment, the amount of hydrate water melted versus evaporated, and flame temperature. These properties were observed for samples of different physical size. Hydrate formation is a very slow process with pure water and methane. The addition of small amounts of surfactant increased substantially the hydrate formation rate. The effects of surfactant on burning characteristics were also studied. One finding

  7. Here's butane hydrates equilibria

    SciTech Connect

    Peettman, F.H.

    1984-06-01

    In 1961 McLeod and Campbell studied hydrates formation for binary mixtures of methane with ethane through butane at pressures up to 10,000 psia. Their data showed that butane lowered the pressure of hydrate formation for methane up to pressures ranging from 1,500 to 2,000 psia. At pressures above this range methane-n-butane mixtures generally followed the curve for pure methane or were slightly above it. McLeod and Campbell conclude that the crystal lattice is deformed at higher pressures (above 6,000 psia) and that hydrate composition on a water-free basis is the same as the gas.

  8. Stereoselective sulphate conjugation of racemic terbutaline by human liver cytosol.

    PubMed

    Walle, T; Walle, U K

    1990-07-01

    1. The enantioselectivity of the sulphation of racemic terbutaline by phenolsulphotransferases was examined in vitro using cytosol from human livers (n = 3) and [35S]-3'-phosphoadenosine-5'-phosphosulphate (PAP35S) as the sulphate donor. 2. The radioactive sulphate conjugate formed was isolated by h.p.l.c. and its enantiomers were separated intact by h.p.l.c. after chiral derivatization. 3. Sulphation of racemic terbutaline occurred with the same apparent Km value for both enantiomers (270 microM). The extent of sulphation of the (+)-enantiomer was double that of the (-)-enantiomer, solely due to a difference in their apparent Vmax values. 4. Sulphation of racemic prenalterol, a structural analogue of terbutaline, also showed a two-fold preference for the (+)-enantiomer. 5. These findings suggest that enantioselective sulphate conjugation of chiral phenolic sympathomimetic amine drugs may lead to enantioselective pharmacokinetics that should be considered in the clinical use of these drugs. PMID:2390423

  9. Transformations in methane hydrates

    USGS Publications Warehouse

    Chou, I.-Ming; Sharma, A.; Burruss, R.C.; Shu, J.; Mao, Ho-kwang; Hemley, R.J.; Goncharov, A.F.; Stern, L.A.; Kirby, S.H.

    2000-01-01

    Detailed study of pure methane hydrate in a diamond cell with in situ optical, Raman, and x-ray microprobe techniques reveals two previously unknown structures, structure II and structure H, at high pressures. The structure II methane hydrate at 250 MPa has a cubic unit cell of a = 17.158(2) A?? and volume V = 5051.3(13) A??3; structure H at 600 MPa has a hexagonal unit cell of a = 11.980(2) A??, c = 9.992(3) A??, and V = 1241.9(5) A??3. The compositions of these two investigated phases are still not known. With the effects of pressure and the presence of other gases in the structure, the structure II phase is likely to dominate over the known structure I methane hydrate within deep hydrate-bearing sediments underlying continental margins.

  10. Withdrawing Nutrition, Hydration

    Cancer.gov

    Module eleven of the EPEC-O Self-Study Original Version discusses the general aspects of withholding or withdrawing of life-sustaining therapies, and presents a specific application to artificial nutrition and hydration.

  11. Chondroitin sulphate inhibits connective tissue mast cells

    PubMed Central

    Theoharides, T C; Patra, P; Boucher, W; Letourneau, R; Kempuraj, D; Chiang, G; Jeudy, S; Hesse, Leah; Athanasiou, A

    2000-01-01

    Mast cells derive from the bone marrow and are responsible for the development of allergic and possibly inflammatory reactions. Mast cells are stimulated by immunoglobulin E (IgE) and specific antigen, but also by a number of neuropeptides such as neurotensin (NT), somatostatin or substance P (SP), to secrete numerous pro-inflammatory molecules that include histamine, cytokines and proteolytic enzymes.Chondroitin sulphate, a major constituent of connective tissues and of mast cell secretory granules, had a dose-dependent inhibitory effect on rat peritoneal mast cell release of histamine induced by the mast cell secretagogue compound 48/80 (48/80). This inhibition was stronger than that of the clinically available mast cell ‘stabilizer' disodium cromoglycate (cromolyn). Inhibition by chondroitin sulphate increased with the length of preincubation and persisted after the drug was washed off, while the effect of cromolyn was limited by rapid tachyphylaxis.Immunologic stimulation of histamine secretion from rat connective tissue mast cells (CTMC) was also inhibited, but this effect was weaker in umbilical cord-derived human mast cells and was absent in rat basophilic leukemia (RBL) cells which are considered homologous to mucosal mast cells (MMC). Oligo- and monosaccharides were not as effective as the polysaccharides.Inhibition, documented by light and electron microscopy, involved a decrease of intracellular calcium ion levels shown by confocal microscopy and image analysis. Autoradiography at the ultrastructural level showed that chondroitin sulphate was mostly associated with plasma and perigranular membranes.Chondroitin sulphate appears to be a potent mast cell inhibitor of allergic and nonimmune stimulation with potential clinical implications. PMID:11082109

  12. Hydrate morphology: Physical properties of sands with patchy hydrate saturation

    USGS Publications Warehouse

    Dai, S.; Santamarina, J.C.; Waite, William F.; Kneafsey, T.J.

    2012-01-01

    The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.

  13. Bovine aortic chondroitin sulphate- and dermatan sulphate-containing proteoglycans. Isolation, fractionation and chemical characterization.

    PubMed Central

    Kapoor, R; Phelps, C F; Cöster, L; Fransson, L A

    1981-01-01

    1. Guanidinium chloride (4M) in the presence of proteinase inhibitors extracted 90% of bovine aorta galactosaminoglycans as proteoglycans that were subsequently purified by ion-exchange and gel chromatography. 2. Fractionation of the calcium salts of the purified proteoglycans with increasing concentration of ethanol yielded fractions PG-25 (28%), PG-35 (45%) and PG-50 (37%). 3. Fraction PG-50 contained proteochondroitin 6-sulphate, whereas fractions PG-25 and PG-35 were proteodermatan sulphates of greatly different carbohydrate composition; the molar proportions of L-iduronate-N-acetylgalactosamine 4-sulphate, D-glucuronate-N-acetyl-galactosamine 4-sulphate and D-glucuronate-N-acetylgalactosamine 6-sulphate were 75: 18 :7 in fraction PG-25 and 14 :46 :40 in fraction PG-35. 4. The presence of alternating or mixed sequences with L-iduronate- and D-glucuronate-containing repeating disaccharides was indicated by the formation of tetrasaccharides after chondroitinase AC digestion (single L-iduronate residues) and by the release of fragments containing four or five consecutive D-glucuronate-N-acetylgalactosamine repeats after periodate oxidation and alkaline elimination. 5. The amino acid compositions of fractions PG-25 and PG-35 were similar and markedly different from that of fraction PG-50, which also contained more side chains. PMID:6798960

  14. Cryopegs as destabilization factor of intra-permafrost gas hydrates

    NASA Astrophysics Data System (ADS)

    Chuvilin, Evgeny; Bukhanov, Boris; Istomin, Vladimir

    2016-04-01

    A characteristic feature of permafrost soils in the Arctic is widespread intra-permafrost unfrozen brine lenses - cryopegs. They are often found in permafrost horizons in the north part of Western Siberia, in particular, on the Yamal Peninsula. Cryopegs depths in permafrost zone can be tens and hundreds of meters from the top of frozen strata. The chemical composition of natural cryopegs is close to sea waters, but is characterized by high mineralization. They have a sodium-chloride primary composition with a minor amount of sulphate. Mineralization of cryopegs brine is often hundreds of grams per liter, and the temperature is around -6…-8 °C. The formation of cryopegs in permafrost is associated with processes of long-term freezing of sediments and cryogenic concentration of salts and salt solutions in local areas. The cryopegs' formation can take place in the course of permafrost evolution at the sea transgressions and regressions during freezing of saline sea sediments. Very important feature of cryopegs in permafrost is their transformation in the process of changing temperature and pressure conditions. As a result, the salinity and chemical composition are changed and in addition the cryopegs' location can be changed during their migration. The cryopegs migration violates the thermodynamic conditions of existence intra-permafrost gas hydrate formations, especially the relic gas hydrates deposits, which are situated in the shallow permafrost up to 100 meters depth in a metastable state [1]. The interaction cryopegs with gas hydrates accumulations can cause decomposition of intra-permafrost hydrates. Moreover, the increasing of salt and unfrozen water content in sedimentary rocks sharply reduce the efficiency of gas hydrates self-preservation in frozen soils. It is confirmed by experimental investigations of interaction of frozen gas hydrate bearing sediments with salt solutions [2]. So, horizons with elevated pressure can appear, as a result of gas hydrate

  15. Influence of sulphate on the reduction of cadmium toxicity in the microalga Chlamydomonas moewusii.

    PubMed

    Mera, Roi; Torres, Enrique; Abalde, Julio

    2016-06-01

    Cadmium is considered as one of the most hazardous metals for living organism and ecosystems. Environmental factors play an important role since they alter the toxicity of metals by varying the bioavailability of these elements for the organisms. The aim of the present study was to investigate, using the freshwater microalga Chlamydomonas moewusii, the existence of an interaction between cadmium and sulphate as a factor that varied the toxicity of this metal. Different cell parameters such as cell growth, content of chlorophylls and biosynthesis of phytochelatins (PCs) were determined. A two-way ANOVA showed that the interaction had a significant effect size of 21% (p<0.001) for the growth of this microalga and around of a 6% on the content of chlorophylls/cell. The effect of this inhibition was that when the concentration of sulphate increased, a lower toxic effect of cadmium on the growth and on the content of chlorophylls was observed. In addition, the increase of sulphate concentration allowed the biosynthesis of a higher amount of PCs and/or PCs with higher chain length. This higher biosynthesis was responsible for the reduction of the toxic effect of cadmium and explained the interaction. PMID:26963118

  16. Tetanus toxoid purification: chromatographic procedures as an alternative to ammonium-sulphate precipitation.

    PubMed

    Stojićević, Ivana; Dimitrijević, Ljiljana; Dovezenski, Nebojša; Živković, Irena; Petrušić, Vladimir; Marinković, Emilija; Inić-Kanada, Aleksandra; Stojanović, Marijana

    2011-08-01

    Given an existing demand to establish a process of tetanus vaccine production in a way that allows its complete validation and standardization, this paper focuses on tetanus toxoid purification step. More precisely, we were looking at a possibility to replace the widely used ammonium-sulphate precipitation by a chromatographic method. Based on the tetanus toxin's biochemical characteristics, we have decided to examine the possibility of tetanus toxoid purification by hydrophobic chromatography, and by chromatographic techniques based on interaction with immobilized metal ions, i.e. chelating chromatography and immobilized metal affinity chromatography. We used samples obtained from differently fragmented crude tetanus toxins by formaldehyde treatment (assigned as TTd-A and TTd-B) as starting material for tetanus toxoid purification. Obtained results imply that purification of tetanus toxoid by hydrophobic chromatography represents a good alternative to ammonium-sulphate precipitation. Tetanus toxoid preparations obtained by hydrophobic chromatography were similar to those obtained by ammonium-sulphate precipitation in respect to yield, purity and immunogenicity. In addition, their immunogenicity was similar to standard tetanus toxoid preparation (NIBSC, Potters Bar, UK). Furthermore, the characteristics of crude tetanus toxin preparations had the lowest impact on the final purification product when hydrophobic chromatography was the applied method of tetanus toxoid purification. On the other hand, purifications of tetanus toxoid by chelating chromatography or immobilized metal affinity chromatography generally resulted in a very low yield due to not satisfactory tetanus toxoid binding to the column, and immunogenicity of the obtained tetanus toxoid-containing preparations was poor.

  17. Treatment of ovine virulent footrot with zinc sulphate/sodium lauryl sulphate footbathing.

    PubMed

    Malecki, J C; Coffey, L

    1987-10-01

    Trials were conducted on 2 commercial sheep flocks in the Gippsland region of Victoria to determine the efficacy of treating ovine virulent footrot by footbathing in aqueous zinc sulphate solution (20% w/v). The effects of foot paring, parenteral penicillin, vaccination and addition of sodium lauryl sulphate (SLS) to the footbaths were assessed. Trial 1 comprised 297 sheep with an initial prevalence of footrot of 33% and most lesions were severe and chronic. Treatment of sheep with unpared feet by zinc sulphate footbathing for 1h did not result in a significant reduction in footrot prevalence (n = 120, cure rate 33%) whereas a significant (P less than 0.01) response was obtained by footbathing for 1h with zinc sulphate/SLS (n = 120, cure rate 55%). Trial 2 comprised 1,042 sheep with a pretreatment footrot prevalence of 71% and predominantly severe lesions. In this flock all treated sheep were footbathed in zinc sulphate/SLS for 1h on 2 occasions, 5 days apart and the effects of additional surgical and parenteral treatments were assessed. Foot paring had a significant detrimental effect on cure rate (P less than 0.01). The administration of procaine penicillin at the time of the first footbathing with zinc sulphate/SLS made no significant improvement to the rate of cure. Footrot vaccine given 8 and 2 weeks prior to footbathing did not cure significantly more sheep than footbathing alone, but the results were significantly better than from foot paring plus footbathing, and from combined foot paring, footbathing and parenteral penincillin treatment (P less than 0.01). The cure rate was 84% for sheep that were only footbathed, 72% for those foot pared and footbathed, 72% for those foot pared, footbathed and given penicillin, and 88% for those vaccinated and footbathed.

  18. Detailed analysis of methane hydrate concentrated zone of lobe type

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Saeki, T.; Inamori, T.; Fujii, T.; Shimoda, N.

    2007-12-01

    Japan Oil, Gas and Metals National Corporation (hereinafter called JOGMEC), as a member of MH21 Research Consortium, takes charge of a study of the Research for Resources Assessment, and is pursuing a possibility that methane hydrate, which is presumed to be distributed around ocean area of Japan, will be energy resources. JOGMEC is currently conducting analysis of seismic data which was acquired by 3D seismic survey conducted from Tokai-Oki to Kumano-nada in the eastern Nankai Trough by METI (Ministry of Economy, Trade and Industry) in 2002 under the national program of assessment for methane hydrates as energy resources. It was understood that methane hydrate was correlated to high resistivity and high velocity based on the results of drilling surveys and velocity analysis, and that methane hydrate concentrated zones can be roughly classified into the channels and lobes in seismic geomorphology because they were characterized with reserves consisting turbidite sand bodies. In this study, the detailed analysis of the inner structure of the methane hydrate concentrated zone of lobe type was conducted to understand the occurrence configurations of methane hydrates. The reflected waves that construct the methane hydrate concentrated zones in the seismic data were extracted and those reflected waves were classified into some groups every one reflector. As the result, some reflectors that construct the methane hydrate concentrated zones were revealed. Those reflectors show the layers including methane hydrates, and the detailed distribution of the methane hydrates in those layers was revealed by the intensity distribution of the amplitude. This time, we introduce the example of the detailed analysis of the methane hydrate concentrated zone in the lobe of submarine fan.

  19. Natural gas hydrates

    SciTech Connect

    Sloan, E.D. Jr. )

    1991-12-01

    This paper reports on gas clathrates (commonly called hydrates), which are crystalline compounds that occur when water form a cage-like structure around smaller guest molecules. Gas hydrates of interest to the natural gas hydrocarbon industry are composed of water and eight molecules: methane, ethane, propane, isobutane, normal butane, nitrogen, carbon dioxide, and hydrogen sulfide. Hydrate formation is possible in any place where water exists with such molecules - in natural or artificial environments and at temperatures above and below 32{degrees} F when the pressure is elevated. Hydrates are considered a nuisance because they block transmission lines, plug blowout preventers, jeopardize the foundations of deepwater platforms and pipelines, cause tubing and casing collapse, and foul process heat exchangers, valves, and expanders. Common examples of preventive measures are the regulation of pipeline water content, unusual drilling-mud compositions, and large quantities of methanol injection into pipelines. We encounter conditions that encourage hydrate formation as we explore more unusual environments for gas and oil, including deepwater frontiers and permafrost regions.

  20. Isotopic archives of sulphate in speleothems

    NASA Astrophysics Data System (ADS)

    Wynn, Peter M.; Fairchild, Ian J.; Baker, Andy; Baldini, James U. L.; McDermott, Frank

    2008-05-01

    The hemispheric impact of industrial emissions upon atmospheric sulphur loading is reflected in the sulphur depositional history recorded in cores from ice sheets. However, these do not reveal regional variations. Recently deposited speleothems are used here as archives of regional sulphur depositional history at two locations within the United Kingdom and Ireland. δ34S-SO4 and δ18O-SO4 present within speleothem carbonate are measured for the first time as part of a dual isotope approach to decode the speleothem sulphur record. The largely refractory nature of δ34S-SO4 under oxidising conditions enables source provenance of atmospheric SO2, whereas the complex cycles of isotopic exchange and fractionation during incorporation of oxygen into sulphate molecules enable δ18O-SO4 signatures to yield insights into ambient environmental conditions and biogeochemical cycling in the ecosystem above the cave. δ34S-SO4 values extracted from speleothem carbonate formed within Browns Folly Mine, UK, range from +3.5 to +5.5‰ and δ18O-SO4 +10.3 to +13.7‰. Both signatures lie within the range expected from sulphate deposition in industrial locations and reflect the transfer of sulphate into speleothem calcite with little fractionation. However, δ18O-SO4 signatures at Crag Cave, western Ireland, are isotopically heavier than expected and approach isotopic equilibrium with δ18O-H2O under reducing conditions. Dual isotope analysis of δ34S-SO4 and δ18O-SO4 optimises the correct identification of sulphur sources and biogeochemical cycling prior to incorporation into the speleothem record. At carefully selected cave sites where drip water flowpaths into the cave remain oxic, speleothems hold the potential to retain records of atmospheric sulphur loading at the local and regional scale.

  1. HYDRATE CORE DRILLING TESTS

    SciTech Connect

    John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

    2002-11-01

    The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate formation comprised of coarse, large

  2. Tinospora cordifolia consumption ameliorates changes in kidney chondroitin sulphate/dermatan sulphate in diabetic rats

    PubMed Central

    Joladarashi, Darukeshwara; Chilkunda, Nandini D.; Salimath, Paramahans V.

    2012-01-01

    Diabetes is known to alter kidney extracellular matrix (ECM) components. Chondroitin sulphate (CS)/dermatan sulphate (DS), an ECM component, which plays an essential role in kidney is altered during diabetes. The focus of this study has been to examine the effect of Tinospora cordifolia (TC) consumption, a potent plant widely used to treat diabetes, on kidney CS/DS. Experimentally induced diabetic rats were fed with diet containing TC at 2·5 and 5 % levels and the effect of it on kidney CS/DS was examined. The CS/DS content and CS:heparan sulphate ratio which was decreased during diabetic condition were ameliorated in TC-fed groups. Disaccharide composition analysis of CS/DS by HPLC showed that decreases in ‘E’ units and degree of sulphation were modulated in 5 % TC-fed groups. Apparent molecular weight of purified CS/DS from the control rat kidney was found to be 38 kDa which was decreased to 29 kDa in diabetic rat kidney. Rats in 5 % TC-fed groups showed chain length of 38 kDa akin to control rats. Expression of chondroitin 4-O-sulfotransferase-1, dermatan 4-O-sulfotransferase-1 and N-acetylgalactosamine 4 sulphate 6-O-sulfotransferase, enzymes involved in the synthesis of ‘E’ units which was reduced during diabetic condition, was significantly contained in the 5 % TC-fed group. Purified CS/DS from 5 % TC-fed group was able to bind higher amounts of ECM components, namely type IV collagen and laminin, when compared with untreated diabetic rats. The present results demonstrate that consumption of a diet containing TC at the 5 % level modulates changes in kidney CS/DS which were due to diabetes. PMID:25191554

  3. Dynamics of protein hydration water.

    PubMed

    Wolf, M; Emmert, S; Gulich, R; Lunkenheimer, P; Loidl, A

    2015-09-01

    We present the frequency- and temperature-dependent dielectric properties of lysozyme solutions in a broad concentration regime, measured at subzero temperatures, and compare the results with measurements above the freezing point of water and on hydrated lysozyme powder. Our experiments allow examining the dynamics of unfreezable hydration water in a broad temperature range. The obtained results prove the bimodality of the hydration shell dynamics. In addition, we find indications of a fragile-to-strong transition of hydration water. PMID:26465518

  4. Improved lead recovery and sulphate removal from used lead acid battery through electrokinetic technique.

    PubMed

    Soundarrajan, C; Sivasankar, A; Maruthamuthu, S; Veluchamy, A

    2012-05-30

    This paper presents improvement in lead (Pb) recovery and sulphate removal from used Pb acid battery (ULAB) through Electrokinetic technique, a process aimed to eliminate environmental pollution that arises due to emission of gases and metal particles from the existing high temperature pyrometallurgical process. Two different cell configurations, (1) one with Nafion membrane placed between anode and middle compartments and Agar membrane between cathode and middle compartments and (2) another with only Agar membrane placed between both sides of the middle compartments were designed for the Pb and sulphate separation from ULAB. This paper concludes that the cell with only Agar membranes performed better than the cell with Nafion and Agar membranes in combinations and also explains the mechanism underlying the chemical and electrochemical processes in the cell.

  5. Aluminum Sulfate 18 Hydrate

    ERIC Educational Resources Information Center

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) of the chemical, aluminum sulfate 18 hydrate, is presented. The profile lists physical and harmful properties, exposure limits, reactivity risks, and symptoms of major exposure for the benefit of teachers and students using the chemical in the laboratory.

  6. [Hydration in clinical practice].

    PubMed

    Maristany, Cleofé Pérez-Portabella; Segurola Gurruchaga, Hegoi

    2011-01-01

    Water is an essential foundation for life, having both a regulatory and structural function. The former results from active and passive participation in all metabolic reactions, and its role in conserving and maintaining body temperature. Structurally speaking it is the major contributer to tissue mass, accounting for 60% of the basis of blood plasma, intracellular and intersticial fluid. Water is also part of the primary structures of life such as genetic material or proteins. Therefore, it is necessary that the nurse makes an early assessment of patients water needs to detect if there are signs of electrolyte imbalance. Dehydration can be a very serious problem, especially in children and the elderly. Dehydrations treatment with oral rehydration solution decreases the risk of developing hydration disorders, but even so, it is recommended to follow preventive measures to reduce the incidence and severity of dehydration. The key to having a proper hydration is prevention. Artificial nutrition encompasses the need for precise calculation of water needs in enteral nutrition as parenteral, so the nurse should be part of this process and use the tools for calculating the patient's requirements. All this helps to ensure an optimal nutritional status in patients at risk. Ethical dilemmas are becoming increasingly common in clinical practice. On the subject of artificial nutrition and hydration, there isn't yet any unanimous agreement regarding hydration as a basic care. It is necessary to take decisions in consensus with the health team, always thinking of the best interests of the patient.

  7. Many-body exchange-repulsion in polarizable molecular mechanics. I. Orbital-based approximations and applications to hydrated metal cation complexes.

    PubMed

    Chaudret, Robin; Gresh, Nohad; Parisel, Olivier; Piquemal, Jean-Philip

    2011-11-15

    We have quantified the extent of the nonadditivity of the short-range exchange-repulsion energy, E(exch-rep), in several polycoordinated complexes of alkali, alkaline-earth, transition, and metal cations. This was done by performing ab initio energy decomposition analyses of interaction energies in these complexes. The magnitude of E(exch-rep(n-body, n > 2)) was found to be strongly cation-dependent, ranging from close to zero for some alkali metal complexes to about 6 kcal/mol for the hexahydrated Zn(2+) complex. In all cases, the cation-water molecules, E(exch-rep(three-body)), has been found to be the dominant contribution to many-body exchange-repulsion effects, higher order terms being negligible. As the physical basis of this effect is discussed, a three-center exponential term was introduced in the SIBFA (Sum of Interactions Between Fragments Ab initio computed) polarizable molecular mechanics procedure to model such effects. The three-body correction is added to the two-center (two-body) overlap-like formulation of the short-range repulsion contribution, E(rep), which is grounded on simplified integrals obtained from localized molecular orbital theory. The present term is computed on using mostly precomputed two-body terms and, therefore, does not increase significantly the computational cost of the method. It was shown to match closely E(three-body) in a series of test cases bearing on the complexes of Ca(2+), Zn(2+), and Hg(2+). For example, its introduction enabled to restore the correct tetrahedral versus square planar preference found from quantum chemistry calculations on the tetrahydrate of Hg(2+) and [Hg(H(2)O)(4)](2+). PMID:21793002

  8. 21 CFR 520.62 - Aminopentamide hydrogen sulphate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aminopentamide hydrogen sulphate tablets. 520.62 Section 520.62 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Aminopentamide hydrogen sulphate tablets. (a) Chemical name. 4-(Dimethylamino)-2,2-diphenylvaleramide...

  9. New Sulphated Flavonoids from Wissadula periplocifolia (L.) C. Presl (Malvaceae).

    PubMed

    Teles, Yanna C F; Horta, Carolina Campolina Rebello; Agra, Maria de Fátima; Siheri, Weam; Boyd, Marie; Igoli, John O; Gray, Alexander I; de Souza, Maria de Fátima Vanderlei

    2015-11-09

    Wissadula periplocifolia (L.) C. Presl (Malvaceae) is commonly used in Brazil to treat bee stings and as an antiseptic. The antioxidant properties of its extracts have been previously demonstrated, thus justifying a phytochemical investigation for its bioactive phenolic constituents. This has yielded five new sulphated flavonoids: 8-O-sulphate isoscutellarein (yannin) (1a); 4'-O-methyl-7-O-sulphate isoscutellarein (beltraonin) (1b); 7-O-sulphate acacetin (wissadulin) (2a); 4'-O-methyl-8-O-sulphate isoscutellarein (caicoine) (2b) and 3'-O-methyl-8-O-sulphate hypolaetin (pedroin) (3b) along with the known flavonoids 7,4'-di-O-methyl-8-O-sulphate isoscutellarein (4), acacetin, apigenin, isoscutellarein, 4'-O-methyl isoscutellarein, 7,4'-di-O-methylisoscutellarein, astragalin and tiliroside. The compounds were isolated by column chromatography and identified by NMR (¹H, (13)C, HMQC, HMBC and COSY) and LC-HRMS. A cell based assay was carried out to evaluate the preliminary cytotoxic properties of the flavonoids against UVW glioma and PC-3M prostate cancer cells as well as non-tumour cell lines. The obtained results showed that acacetin, tiliroside, a mixture of acacetin + apigenin and the sulphated flavonoids 2a + 2b exhibited inhibitory activity against at least one of the cell lines tested. Among the tested flavonoids acacetin and tiliroside showed lower IC50 values, presenting promising antitumor effects.

  10. New Sulphated Flavonoids from Wissadula periplocifolia (L.) C. Presl (Malvaceae).

    PubMed

    Teles, Yanna C F; Horta, Carolina Campolina Rebello; de Fátima Agra, Maria; Siheri, Weam; Boyd, Marie; Igoli, John O; Gray, Alexander I; de Fátima Vanderlei de Souza, Maria

    2015-11-09

    Wissadula periplocifolia (L.) C. Presl (Malvaceae) is commonly used in Brazil to treat bee stings and as an antiseptic. The antioxidant properties of its extracts have been previously demonstrated, thus justifying a phytochemical investigation for its bioactive phenolic constituents. This has yielded five new sulphated flavonoids: 8-O-sulphate isoscutellarein (yannin) (1a); 4'-O-methyl-7-O-sulphate isoscutellarein (beltraonin) (1b); 7-O-sulphate acacetin (wissadulin) (2a); 4'-O-methyl-8-O-sulphate isoscutellarein (caicoine) (2b) and 3'-O-methyl-8-O-sulphate hypolaetin (pedroin) (3b) along with the known flavonoids 7,4'-di-O-methyl-8-O-sulphate isoscutellarein (4), acacetin, apigenin, isoscutellarein, 4´-O-methyl isoscutellarein, 7,4'-di-O-methylisoscutellarein, astragalin and tiliroside. The compounds were isolated by column chromatography and identified by NMR (¹H, 13C, HMQC, HMBC and COSY) and LC-HRMS. A cell based assay was carried out to evaluate the preliminary cytotoxic properties of the flavonoids against UVW glioma and PC-3M prostate cancer cells as well as non-tumour cell lines. The obtained results showed that acacetin, tiliroside, a mixture of acacetin+apigenin and the sulphated flavonoids 2a+2b exhibited inhibitory activity against at least one of the cell lines tested. Among the tested flavonoids acacetin and tiliroside showed lower IC50 values, presenting promising antitumor effects.

  11. 21 CFR 520.62 - Aminopentamide hydrogen sulphate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aminopentamide hydrogen sulphate tablets. 520.62 Section 520.62 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Aminopentamide hydrogen sulphate tablets. (a) Chemical name. 4-(Dimethylamino)-2,2-diphenylvaleramide...

  12. 21 CFR 520.62 - Aminopentamide hydrogen sulphate tablets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aminopentamide hydrogen sulphate tablets. 520.62 Section 520.62 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Aminopentamide hydrogen sulphate tablets. (a) Chemical name. 4-(Dimethylamino)-2,2-diphenylvaleramide...

  13. 21 CFR 520.62 - Aminopentamide hydrogen sulphate tablets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aminopentamide hydrogen sulphate tablets. 520.62 Section 520.62 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Aminopentamide hydrogen sulphate tablets. (a) Chemical name. 4-(Dimethylamino)-2,2-diphenylvaleramide...

  14. 21 CFR 520.62 - Aminopentamide hydrogen sulphate tablets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aminopentamide hydrogen sulphate tablets. 520.62 Section 520.62 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Aminopentamide hydrogen sulphate tablets. (a) Chemical name. 4-(Dimethylamino)-2,2-diphenylvaleramide...

  15. Sulphate release from construction and demolition material in soils

    NASA Astrophysics Data System (ADS)

    Abel, Stefan; Wessolek, Gerd

    2013-04-01

    In Berlin and many other cities soils are heavily influenced by anthropogenic activities and deposited substrates. A widespread technical substrate in technosols is construction and demolition material from residential and industrial buildings. Existing rubble landfills without sealing facilities pose threats to ground water quality. In the central city of Berlin rising sulphate concentrations of groundwaters (up to 1200 mg/L) are measured since more than two decades. Previous studies point out that the high sulphate concentrations are mainly attributed to World War II rubble. The major part of debris was deposited in form of landfills and contains approximately 0.3 wt% gypsum. The scope of our research is to determine mechanisms of sulphate release from debris material, interactions between sulphate release, soil hydraulic properties and potential sinks of sulphur. To estimate equilibrium concentration and kinetics of sulphate release of various debris components batch and column experiments are conducted. The same method is applied to determine potential adsorptive character of common debris components. To analyse the impacts of soil hydraulic properties on sulphate leaching we carry out soil column experiments with defined upper and lower boundary conditions, varying water flow velocity and induced preferential flow. Simultaneously we monitor sulphate concentration of soil leachate in a 2 m³ lysimeter. First results of the batch experiments show that gypsum from broken stucco is the main source of sulphate in the observed technosols. Other components as mortar and slag show a quite low sulphate release. Similar results are found within the column experiments. For brigs medium and strongly time dependent sulphate release is determined. Concentrations up to 1500 mg/L are measured in the soil leachate from the lysimeter.

  16. Rare earth element geochemistry in cold-seep pore waters of Hydrate Ridge, northeast Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Himmler, Tobias; Haley, Brian A.; Torres, Marta E.; Klinkhammer, Gary P.; Bohrmann, Gerhard; Peckmann, Jörn

    2013-07-01

    The concentrations of rare earth elements (REEs), sulphate, hydrogen sulphide, total alkalinity, calcium, magnesium and phosphate were measured in shallow (<12 cm below seafloor) pore waters from cold-seep sediments on the northern and southern summits of Hydrate Ridge, offshore Oregon. Downward-decreasing sulphate and coevally increasing sulphide concentrations reveal sulphate reduction as dominant early diagenetic process from ~2 cm depth downwards. A strong increase of total dissolved REE (∑REE) concentrations is evident immediately below the sediment-water interface, which can be related to early diagenetic release of REEs into pore water resulting from the re-mineralization of particulate organic matter. The highest pore water ∑REE concentrations were measured close to the sediment-water interface at ~2 cm depth. Distinct shale-normalized REE patterns point to particulate organic matter and iron oxides as main REE sources in the upper ~2-cm depth interval. In general, the pore waters have shale-normalized patterns reflecting heavy REE (HREE) enrichment, which suggests preferential complexation of HREEs with carbonate ions. Below ~2 cm depth, a downward decrease in ∑REE correlates with a decrease in pore water calcium concentrations. At this depth, the anaerobic oxidation of methane (AOM) coupled to sulphate reduction increases carbonate alkalinity through the production of bicarbonate, which results in the precipitation of carbonate minerals. It seems therefore likely that the REEs and calcium are consumed during vast AOM-induced precipitation of carbonate in shallow Hydrate Ridge sediments. The analysis of pore waters from Hydrate Ridge shed new light on early diagenetic processes at cold seeps, corroborating the great potential of REEs to identify geochemical processes and to constrain environmental conditions.

  17. Steroid hormone sulphation in lead workers.

    PubMed Central

    Apostoli, P; Romeo, L; Peroni, E; Ferioli, A; Ferrari, S; Pasini, F; Aprili, F

    1989-01-01

    The metabolism of steroid hormones has been investigated in 10 workers exposed to lead and in 10 non-exposed subjects to determine whether lead interferes with the first or second phase reactions of steroid hormone biotransformation, or both. In the exposed workers blood lead concentrations (PbB) ranged from 45 to 69 micrograms/100 ml; in the controls PbB was less than 25 micrograms/100 ml. No statistical differences were found for the total amount of the urinary hormone metabolites, but a drop of about 50% was observed for the sulphated portion. It is suggested that lead interferes with the mechanisms of sulphoconjugation through an effect on the cytosol enzymes sulphotransferase and sulphokinase. PMID:2930732

  18. Acid-base titrations in nonaqueous solvents Analysis of dimethyl sulphate.

    PubMed

    Banick, W M; Francis, E C

    1966-07-01

    A nonaqueous titrimetric procedure was developed for the determination of the dimethyl sulphate, methyl hydrogen sulphate and sulphuric acid content of dimethyl sulphate samples. Methyl hydrogen sulphate and sulphuric acid are determined by a differentiating potentiometric titration in pyridine with tributylethylammonium hydroxide. Pyridine converts the dimethyl sulphate into the weakly acidic methylpyridinium methyl sulphate which does not interfere in the titration. Dimethyl sulphate is determined by reacting it with an excess of 2-dimethylaminoethanol and titrating the excess with perchloric acid. Precision and recovery data for commercial samples of dimethyl sulphate are presented.

  19. Methane Clathrate Hydrate Prospecting

    NASA Technical Reports Server (NTRS)

    Duxbury, N.; Romanovsky, V.

    2003-01-01

    A method of prospecting for methane has been devised. The impetus for this method lies in the abundance of CH4 and the growing shortages of other fuels. The method is intended especially to enable identification of subpermafrost locations where significant amounts of methane are trapped in the form of methane gas hydrate (CH4(raised dot)6H2O). It has been estimated by the U.S. Geological Survey that the total CH4 resource in CH4(raised dot) 6H2O exceeds the energy content of all other fossil fuels (oil, coal, and natural gas from non-hydrate sources). Also, CH4(raised dot)6H2O is among the cleanest-burning fuels, and CH4 is the most efficient fuel because the carbon in CH4 is in its most reduced state. The method involves looking for a proxy for methane gas hydrate, by means of the combination of a thermal-analysis submethod and a field submethod that does not involve drilling. The absence of drilling makes this method easier and less expensive, in comparison with prior methods of prospecting for oil and natural gas. The proposed method would include thermoprospecting in combination with one more of the other non-drilling measurement techniques, which could include magneto-telluric sounding and/or a subsurface-electrical-resistivity technique. The method would exploit the fact that the electrical conductivity in the underlying thawed region is greater than that in the overlying permafrost.

  20. Concrete under sulphate attack: an isotope study on sulphur sources.

    PubMed

    Mittermayr, Florian; Bauer, Christoph; Klammer, Dietmar; Böttcher, Michael E; Leis, Albrecht; Escher, Peter; Dietzel, Martin

    2012-01-01

    The formation of secondary sulphate minerals such as thaumasite, ettringite and gypsum is a process causing severe damage to concrete constructions. A major key to understand the complex reactions, involving concrete deterioration is to decipher the cause of its appearance, including the sources of the involved elements. In the present study, sulphate attack on the concrete of two Austrian tunnels is investigated. The distribution of stable sulphur isotopes is successfully applied to decipher the source(s) of sulphur in the deteriorating sulphate-bearing minerals. Interestingly, δ(34)S values of sulphate in local groundwater and in the deteriorating minerals are mostly in the range from+14 to+27 ‰. These δ(34)S values match the isotope patterns of regional Permian and Triassic marine evaporites. Soot relicts from steam- and diesel-driven trains found in one of the tunnels show δ(34)S values from-3 to+5 ‰, and are therefore assumed to be of minor importance for sulphate attack on the concretes. In areas of pyrite-containing sedimentary rocks, the δ(34)S values of sulphate from damaged concrete range between-1 and+11 ‰. The latter range reflects the impact of sulphide oxidation on local groundwater sulphate.

  1. Concrete under sulphate attack: an isotope study on sulphur sources.

    PubMed

    Mittermayr, Florian; Bauer, Christoph; Klammer, Dietmar; Böttcher, Michael E; Leis, Albrecht; Escher, Peter; Dietzel, Martin

    2012-01-01

    The formation of secondary sulphate minerals such as thaumasite, ettringite and gypsum is a process causing severe damage to concrete constructions. A major key to understand the complex reactions, involving concrete deterioration is to decipher the cause of its appearance, including the sources of the involved elements. In the present study, sulphate attack on the concrete of two Austrian tunnels is investigated. The distribution of stable sulphur isotopes is successfully applied to decipher the source(s) of sulphur in the deteriorating sulphate-bearing minerals. Interestingly, δ(34)S values of sulphate in local groundwater and in the deteriorating minerals are mostly in the range from+14 to+27 ‰. These δ(34)S values match the isotope patterns of regional Permian and Triassic marine evaporites. Soot relicts from steam- and diesel-driven trains found in one of the tunnels show δ(34)S values from-3 to+5 ‰, and are therefore assumed to be of minor importance for sulphate attack on the concretes. In areas of pyrite-containing sedimentary rocks, the δ(34)S values of sulphate from damaged concrete range between-1 and+11 ‰. The latter range reflects the impact of sulphide oxidation on local groundwater sulphate. PMID:22321257

  2. Hydration-dependent dynamic crossover phenomenon in protein hydration water

    NASA Astrophysics Data System (ADS)

    Wang, Zhe; Fratini, Emiliano; Li, Mingda; Le, Peisi; Mamontov, Eugene; Baglioni, Piero; Chen, Sow-Hsin

    2014-10-01

    The characteristic relaxation time τ of protein hydration water exhibits a strong hydration level h dependence. The dynamic crossover is observed when h is higher than the monolayer hydration level hc=0.2-0.25 and becomes more visible as h increases. When h is lower than hc, τ only exhibits Arrhenius behavior in the measured temperature range. The activation energy of the Arrhenius behavior is insensitive to h, indicating a local-like motion. Moreover, the h dependence of the crossover temperature shows that the protein dynamic transition is not directly or solely induced by the dynamic crossover in the hydration water.

  3. Rapid gas hydrate formation process

    DOEpatents

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  4. Global occurrences of gas hydrate

    USGS Publications Warehouse

    Kvenvolden, K.A.; Lorenson, T.D.

    2001-01-01

    Natural gas hydrate is found worldwide in sediments of outer continental margins of all oceans and in polar areas with continuous permafrost. There are currently 77 localities identified globally where geophysical, geochemical and/or geological evidence indicates the presence of gas hydrate. Details concerning individual gas-hydrate occurrences are compiled at a new world-wide-web (www) site (http://walrus.wr.usgs.gov/globalhydrate). This site has been created to facilitate global gas-hydrate research by providing information on each of the localities where there is evidence for gas hydrate. Also considered are the implications of gas hydrate as a potential (1) energy resource, (2) factor in global climate change, and (3) geohazard.

  5. Sulphate removal from sodium sulphate-rich brine and recovery of barium as a barium salt mixture.

    PubMed

    Vadapalli, Viswanath R K; Zvimba, John N; Mulopo, Jean; Motaung, Solly

    2013-01-01

    Sulphate removal from sodium sulphate-rich brine using barium hydroxide and recovery of the barium salts has been investigated. The sodium sulphate-rich brine treated with different dosages of barium hydroxide to precipitate barium sulphate showed sulphate removal from 13.5 g/L to less than 400 mg/L over 60 min using a barium to sulphate molar ratio of 1.1. The thermal conversion of precipitated barium sulphate to barium sulphide achieved a conversion yield of 85% using coal as both a reducing agent and an energy source. The recovery of a pure mixture of barium salts from barium sulphide, which involved dissolution of barium sulphide and reaction with ammonium hydroxide resulted in recovery of a mixture of barium carbonate (62%) and barium hydroxide (38%), which is a critical input raw material for barium salts based acid mine drainage (AMD) desalination technologies. Under alkaline conditions of this barium salt mixture recovery process, ammonia gas is given off, while hydrogen sulfide is retained in solution as bisulfide species, and this provides basis for ammonium hydroxide separation and recovery for reuse, with hydrogen sulfide also recoverable for further industrial applications such as sulfur production by subsequent stripping.

  6. Gas hydrate cool storage system

    DOEpatents

    Ternes, M.P.; Kedl, R.J.

    1984-09-12

    The invention presented relates to the development of a process utilizing a gas hydrate as a cool storage medium for alleviating electric load demands during peak usage periods. Several objectives of the invention are mentioned concerning the formation of the gas hydrate as storage material in a thermal energy storage system within a heat pump cycle system. The gas hydrate was formed using a refrigerant in water and an example with R-12 refrigerant is included. (BCS)

  7. Effect of temperature on the durability of class C fly ash belite cement in simulated radioactive liquid waste: synergy of chloride and sulphate ions.

    PubMed

    Guerrero, A; Goñi, S; Allegro, V R

    2009-06-15

    The durability of class C fly ash belite cement (FABC-2-W) in simulated radioactive liquid waste (SRLW) rich in a mixed sodium chloride and sulphate solution is presented here. The effect of the temperature and potential synergic effect of chloride and sulfate ions are discussed. This study has been carried out according to the Koch-Steinegger test, at the temperature of 20 degrees C and 40 degrees C during a period of 180 days. The durability has been evaluated by the changes of the flexural strength of mortar, fabricated with this cement, immersed in a simulated radioactive liquid waste rich in sulfate (0.5M), chloride (0.5M) and sodium (1.5M) ions--catalogued like severely aggressive for the traditional Portland cement--and demineralised water, which was used as reference. The reaction mechanism of sulphate, chloride and sodium ions with the mortar was evaluated by scanning electron microscopy (SEM), porosity and pore-size distribution, and X-ray diffraction (XRD). The results showed that the chloride binding and formation of Friedel's salt was inhibited by the presence of sulphate. Sulphate ion reacts preferentially with the calcium aluminate hydrates forming non-expansive ettringite which precipitated inside the pores; the microstructure was refined and the mechanical properties enhanced. This process was faster and more marked at 40 degrees C.

  8. Effect of temperature on the durability of class C fly ash belite cement in simulated radioactive liquid waste: synergy of chloride and sulphate ions.

    PubMed

    Guerrero, A; Goñi, S; Allegro, V R

    2009-06-15

    The durability of class C fly ash belite cement (FABC-2-W) in simulated radioactive liquid waste (SRLW) rich in a mixed sodium chloride and sulphate solution is presented here. The effect of the temperature and potential synergic effect of chloride and sulfate ions are discussed. This study has been carried out according to the Koch-Steinegger test, at the temperature of 20 degrees C and 40 degrees C during a period of 180 days. The durability has been evaluated by the changes of the flexural strength of mortar, fabricated with this cement, immersed in a simulated radioactive liquid waste rich in sulfate (0.5M), chloride (0.5M) and sodium (1.5M) ions--catalogued like severely aggressive for the traditional Portland cement--and demineralised water, which was used as reference. The reaction mechanism of sulphate, chloride and sodium ions with the mortar was evaluated by scanning electron microscopy (SEM), porosity and pore-size distribution, and X-ray diffraction (XRD). The results showed that the chloride binding and formation of Friedel's salt was inhibited by the presence of sulphate. Sulphate ion reacts preferentially with the calcium aluminate hydrates forming non-expansive ettringite which precipitated inside the pores; the microstructure was refined and the mechanical properties enhanced. This process was faster and more marked at 40 degrees C. PMID:19056176

  9. The use of chromic potassium sulphate in bone electron microscopy.

    PubMed

    Liem, R S; Jansen, H W

    1984-10-01

    The ultrastructure of endochondral bone was studied using an aqueous solution of chromic potassium sulphate as the decalcifying agent. 0.5 mm thick sections of rat tibiae were fixed in buffered glutaraldehyde, immersed in an aqueous solution of 1% chromic potassium sulphate pH 3.4, dehydrated and embedded in Poly Bed 812 without exposure to osmium tetroxide. In unstained sections we observed clusters of crystal like structures throughout the osteoid and calcifying cartilage matrix as well as solitary needle shaped structures in association with collagen fibrils. Stained sections revealed nuclei, endoplasmic reticulum, membrane limited dense granules, mitochondrial particles and other cell components typical of bone cells. It appeared that the chromic potassium sulphate method preserves the relationship between hard and soft tissues well, gives fine cytological detail and produces images of intracellular and extracellular deposits identical to untreated crystallites. It is concluded that the chromic potassium sulphate method is indicated for ultrastructural studies of bone.

  10. Perfume interactions with sodium dodecyl sulphate solutions.

    PubMed

    Behan, J M; Perring, K D

    1987-12-01

    Synopsis Vapour phase concentrations of aroma chemicals above a model shampoo system containing sodium dodecyl sulphate (SDS) have been measured using headspace gc methodology. It was shown that, to a first approximation, headspace concentrations were directly related to the phase volumes ratio (water/SDS), and that this could be rationalized in terms of simple partitioning. The headspace behaviour of the same materials dissolved in water and in diethyl phthalate was also investigated with a view to understanding the effect of the medium on the perfume 'profile'. The octanol/water partition coefficient was identified as a potentially useful parameter in this connection. Since the phase structures of the surfactant systems were not known, the results for all the materials were expressed in terms of 'apparent activity coefficients', calculated from headspace concentrations and mole fractions. It was found that, to a first approximation, the headspace concentration of benzyl acetate above these surfactant systems was directly proportional to the phase volumes ratio (water/SDS), and that this could be rationalized in terms of a simple partition model. It was clear, however, that a more sophisticated model would require data on the surfactant/perfume component interaction in the absence of water-such data could be more conveniently obtained using liquid analogues of SDS.

  11. Investigation of shallow gas hydrate occurrence and gas seep activity on the Sakhalin continental slope, Russia

    NASA Astrophysics Data System (ADS)

    Jin, Young Keun; Baranov, Boris; Obzhirov, Anatoly; Salomatin, Alexander; Derkachev, Alexander; Hachikubo, Akihiro; Minami, Hrotsugu; Kuk Hong, Jong

    2016-04-01

    The Sakhalin continental slope has been a well-known gas hydrate area since the first finding of gas hydrate in 1980's. This area belongs to the southernmost glacial sea in the northern hemisphere where most of the area sea is covered by sea ice the winter season. Very high organic carbon content in the sediment, cold sea environment, and active tectonic regime in the Sakhalin slope provide a very favorable condition for occurring shallow gas hydrate accumulation and gas emission phenomena. Research expeditions under the framework of a Korean-Russian-Japanese long-term international collaboration projects (CHAOS, SSGH-I, SSGH-II projects) have been conducted to investigate gas hydrate occurrence and gas seepage activities on the Sakhalin continental slope, Russia from 2003 to 2015. During the expeditions, near-surface gas hydrate samples at more than 30 sites have been retrieved and hundreds of active gas seepage structures on the seafloor were newly registered by multidisciplinary surveys. The gas hydrates occurrence at the various water depths from about 300 m to 1000 m in the study area were accompanied by active gas seepage-related phenomena in the sub-bottom, on the seafloor, and in the water column: well-defined upward gas migration structures (gas chimney) imaged by high-resolution seismic, hydroacoustic anomalies of gas emissions (gas flares) detected by echosounders, seafloor high backscatter intensities (seepage structures) imaged by side-scan sonar and bathymetric structures (pockmarks and mounds) mapped by single/multi-beam surveys, and very shallow SMTZ (sulphate-methane transition zone) depths, strong microbial activities and high methane concentrations measured in sediment/seawater samples. The highlights of the expeditions are shallow gas hydrate occurrences around 300 m in the water depth which is nearly closed to the upper boundary of gas hydrate stability zone in the area and a 2,000 m-high gas flare emitted from the deep seafloor.

  12. Hydrogen peroxide generation from hydrated protein drink mixes.

    PubMed

    Boatright, William L

    2013-11-01

    Generation of oxygen radicals upon hydration of powdered protein products was examined using luminol-enhanced chemiluminescence. Among individual proteins powders examined oxidative bursts occurred almost immediately, and then rapidly declined in the 1st 5 min. Commercially available powdered protein drink mixes behaved differently, with an initial lag phase followed by a sustained increase in luminol-enhanced luminescence, lasting for an hour or beyond. The drink mix that produced the highest level of luminol-enhanced luminescence also contained 379 nM ascorbate radical when hydrated (28 nmole/g of powdered drink mix). The entire ascorbic acid content of this drink mix was oxidized to nondetectable levels (using HPLC-diode array detection) within 60 min of being hydrated. Treatment of the hydrated drink mixes with the enzyme catalase almost completely inhibited the luminol-enhanced luminescence from the hydrated drink mix demonstrating that hydrogen peroxide generated via a chemical reaction among the drink mixes' ingredients was a primary reactive oxygen species (ROS). This is the strongest oxidative capacity demonstrated in a food product as consumed (without any manipulation to increase ROS) and the 1st time that the ascrobate radical in a food product as been quantified. Generation of hydrogen peroxide in the hydrated drink mixes from metal catalyzed reactions involving oxygen and reducing equivalents from ascorbic acid is proposed.

  13. Hydration force between mica surfaces in aqueous KCl electrolyte solution.

    PubMed

    Leng, Yongsheng

    2012-03-27

    Liquid-vapor molecular dynamics simulations are performed to study the interaction forces between two mica surfaces in an aqueous KCl electrolyte solution. Strong repulsive hydration force is obtained within a distance of ~2 nm between the two mica surfaces, which cannot be explained by the continuum theory of double-layer repulsion. We find that this short-range repulsive hydration force is much stronger than the double-layer force between mica surfaces. Whereas the simulation system is much smaller than the surface force measurement system, fundamental mechanisms of repulsive hydration force are revealed. In particular, important features of the step-like force oscillatory behavior during normal compression and force hysteresis during retraction are observed. Detailed analysis of the ionic density distributions shows that the "forced adsorption" of diffusive K(+) ions onto mica surfaces during compression and the subsequent "slow desorption" of the absorbed K(+) ions from mica surfaces upon retraction are responsible for the hysteresis phenomenon. From a mechanics point of view, we attribute the load bearing capacity of the dense electrolyte to the very hard hydration shells of K(+) metal ions under confinement. We find that the hydrated K(+) ions and Cl(-) co-ions remain very diffusive in the aqueous film. Water molecules in the hydration layer are also very fluidic, in the sense that the diffusion constant of water molecules is less than its bulk value by at most 3 orders of magnitude under the extreme confinement. PMID:22369483

  14. High concentrated gas hydrate zone imaged in seismic data

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Saeki, T.; Oikawa, N.; Inamori, T.; Fujii, T.; Takayama, T.; Hayashi, M.; Nakamizu, M.

    2006-12-01

    Japan Oil, Gas and Metals National Corporation (JOGMEC), as a member of MH21 Research Consortium, takes charge of a study of the Research for Resources Assessment, and is pursuing a possibility that gas hydrate, which is presumed to be distributed around ocean area of Japan, will be energy resources. As part of the study, 3D seismic survey was conducted from Tokai-oki to Kumano-nada in the eastern Nankai Trough by METI (Ministry of Economy, Trade and Industry) in 2002 under the national program of assessment for gas hydrates as energy resources. As well as 3D seismic survey, drilling program was conducted in this area and information of physical property was acquired. Additionally, velocity analysis and seismic attribute analysis were conducted. It is revealed that gas hydrate zone is correlated with high resistivity and high velocity, and a lot of gas hydrates are found in turbidite sand with much porosity. JOGMEC is conducting analysis of seismic data and is doing resources assessment of gas hydrate compiling information of physical property which was acquired by drilling, result of velocity analysis, and result of seismic attribute analysis. This time, we introduce some seismic images of high concentrated gas hydrate zone appears in Tokai-oki area.

  15. Biological effects of sulphated insulin in adipocytes and hepatocytes.

    PubMed

    Zeuzem, S; Taylor, R; Agius, L; Schoeffling, K; Albisser, A M; Alberti, K G

    1985-10-01

    The binding affinity of sulphated insulin compared with unmodified, neutral insulin has been reported to be approximately four times lower in human and rat adipocytes but over twenty times lower in rat hepatocytes. In the present study the biological action of sulphated insulin was assessed in rat hepatocytes and human and rat adipocytes. To achieve half-maximal stimulation of fatty acid synthesis in rat hepatocytes about twenty one times higher concentrations of sulphated than neutral insulin were required (15.07 +/- 5.50 vs 0.71 +/- 0.34 nmol/l), this ratio being similar to the ratio of binding affinity in rat hepatocytes. In human adipocytes, half-maximal stimulation of initial rates of glucose uptake was observed at 11.6 +/- 5.1 vs 2.9 +/- 1.3 pmol/l for sulphated and neutral insulin respectively, and half-maximal inhibition of lipolysis at 31.0 +/- 13.5 vs 7.3 +/- 2.5 pmol/l respectively. These data are consistent with the four-fold lower binding affinity of sulphated insulin to human adipocytes. However, in rat adipocytes the biological potency of sulphated insulin was found to be much lower than anticipated from the binding data, half-maximal stimulation of initial rates of glucose uptake being observed at 757 +/- 299 vs 35 +/- 13 pmol/l respectively and half-maximal inhibition of lipolysis at 35.9 +/- 12.1 vs 1.5 +/- 0.5 pmol/l respectively. Thus, in rat adipocytes, approximately 22 times the concentration of sulphated insulin was required to achieve equivalent biological effect. A discrepancy between binding affinity and biological action with respect to sulphated insulin was identified in rat adipocytes but not human adipocytes nor rat hepatocytes suggesting differences in the binding-action linkage in these cells.

  16. Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples

    PubMed Central

    Lombi, Enzo; de Jonge, Martin D.; Donner, Erica; Kopittke, Peter M.; Howard, Daryl L.; Kirkham, Robin; Ryan, Chris G.; Paterson, David

    2011-01-01

    Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples. PMID:21674049

  17. Vibrational spectra of the two hydrates of strontium oxalate.

    PubMed

    D'Antonio, Maria C; Torres, María M; Palacios, Daniel; González-Baró, Ana C; Baran, Enrique J

    2015-02-25

    The infrared and Raman spectra of the two hydrates of strontium oxalate, SrC2O4⋅H2O and SrC2O4⋅2H2O, were recorded and discussed on the basis of their structural peculiarities and in comparison with the spectra of the related calcium oxalates and other previously investigated metallic oxalates.

  18. Fast x-ray fluorescence microtomography of hydrated biological samples.

    PubMed

    Lombi, Enzo; de Jonge, Martin D; Donner, Erica; Kopittke, Peter M; Howard, Daryl L; Kirkham, Robin; Ryan, Chris G; Paterson, David

    2011-01-01

    Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples. PMID:21674049

  19. The healing of gastric ulcers by zinc sulphate.

    PubMed

    Frommer, D J

    1975-11-22

    A double-blind trial of zinc sulphate given by mouth (220 mg, three times a day) and placebo was undertaken in patients with benign gastric ulcers. The drug was given for a three-week period and the healing of the ulcers was estimated from results of barium-meal X-ray films taken immediately before and after this period. There were ten patients taking zinc sulphate and eight patients taking placebo. The two groups of patients were comparable in all respects, including initial ulcer size. Patients taking zinc sulphate had an ulcer healing rate three times that of patients treated with placebo. This difference was significant (P less than 0-05). Complete healing of ulcers occurred more frequently in the patients taking zinc sulphate than in patients treated with placebo. The placebo group contained more patients whose ulcers did not heal at all, than the group taking zinc sulphate. No side effects from zinc sulphate were noted. There was no evidence of zinc deficiency in any of the patients.

  20. Anthropogenic influence on the distribution of tropospheric sulphate aerosol

    NASA Astrophysics Data System (ADS)

    Langner, J.; Rodhe, H.; Crutzen, P. J.; Zimmermann, P.

    1992-10-01

    HUMAN activities have increased global emissions of sulphur gases by about a factor of three during the past century, leading to increased sulphate aerosol concentrations, mainly in the Northern Hemisphere. Sulphate aerosols can affect the climate directly, by increasing the backscattering of solar radiation in cloud-free air, and indirectly, by providing additional cloud condensation nuclei1-4. Here we use a global transport-chemistry model to estimate the changes in the distribution of tropospheric sulphate aerosol and deposition of non-seasalt sulphur that have occurred since pre-industrial times. The increase in sulphate aerosol concentration is small over the Southern Hemisphere oceans, but reaches a factor of 100 over northern Europe in winter. Our calculations indicate, however, that at most 6% of the anthropogenic sulphur emissions is available for the formation of new aerosol particles. This is because about one-half of the sulphur dioxide is deposited on the Earth's surface, and most of the remainder is oxidized in cloud droplets so that the sulphate becomes associated with pre-existing particles. Even so, the rate of formation of new sulphate particles may have doubled since pre-industrial times.

  1. Infrared and Raman spectroscopic characterisation of the sulphate mineral creedite - Ca3Al2SO4(F,OH)·2H2O - and in comparison with the alums

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Xi, Yunfei; Scholz, Ricardo; López, Andrés; Granja, Amanda

    2013-05-01

    The mineral creedite is a fluorinated hydroxy hydrated sulphate of aluminium and calcium of formula Ca3Al2SO4(F,OH)·2H2O. The mineral has been studied by a combination of electron probe analysis to determine the molecular formula of the mineral and the structure assessed by vibrational spectroscopy. The spectroscopy of creedite may be compared with that of the alums. The Raman spectrum of creedite is characterised by an intense sharp band at 986 cm-1 assigned to the SO42- ν1 (Ag) symmetric stretching mode. Multiple bands of creedite in the antisymmetric stretching region support the concept of a reduction in symmetry of the sulphate anion. Multiple bands are also observed in the bending region with the three bands at 601, 629 and 663 cm-1 assigned to the SO42- ν4 (Ag) bending modes. The observation of multiple bands at 440, 457 and 483 cm-1 attributed to the SO42- ν2 (Bg) bending modes supports the concept that the symmetry of the sulphate is reduced by coordination to the water bonded to the Al3+ in the creedite structure. The splitting of the ν2, ν3 and ν4 modes is attributed to the reduction of symmetry of the SO4 and it is proposed that the sulphate coordinates to water in the hydrated aluminium in bidentate chelation.

  2. Infrared and Raman spectroscopic characterisation of the sulphate mineral creedite--Ca3Al2SO4(F,OH)·2H2O--and in comparison with the alums.

    PubMed

    Frost, Ray L; Xi, Yunfei; Scholz, Ricardo; López, Andrés; Granja, Amanda

    2013-05-15

    The mineral creedite is a fluorinated hydroxy hydrated sulphate of aluminium and calcium of formula Ca3Al2SO4(F,OH)·2H2O. The mineral has been studied by a combination of electron probe analysis to determine the molecular formula of the mineral and the structure assessed by vibrational spectroscopy. The spectroscopy of creedite may be compared with that of the alums. The Raman spectrum of creedite is characterised by an intense sharp band at 986 cm(-1) assigned to the SO4(2)- ν1 (Ag) symmetric stretching mode. Multiple bands of creedite in the antisymmetric stretching region support the concept of a reduction in symmetry of the sulphate anion. Multiple bands are also observed in the bending region with the three bands at 601, 629 and 663 cm(-1) assigned to the SO4(2)- ν4 (Ag) bending modes. The observation of multiple bands at 440, 457 and 483 cm(-1) attributed to the SO4(2)- ν2 (Bg) bending modes supports the concept that the symmetry of the sulphate is reduced by coordination to the water bonded to the Al(3+) in the creedite structure. The splitting of the ν2, ν3 and ν4 modes is attributed to the reduction of symmetry of the SO4 and it is proposed that the sulphate coordinates to water in the hydrated aluminium in bidentate chelation.

  3. Sulphated modification of a polysaccharide obtained from fresh persimmon (Diospyros kaki L.) fruit and antioxidant activities of the sulphated derivatives.

    PubMed

    Zhang, Yali; Lu, Xiaoyun; Fu, Zhongbin; Wang, Zibao; Zhang, Jianbao

    2011-08-01

    Free radicals and other reactive oxygen species (ROS) are believed to play significant roles in ageing as well as in a number of degenerative or pathological diseases. This paper reports the preparation, characterisation and potential antioxidant activity of a type of chemically sulphated polysaccharide isolated from fresh persimmon (Diospyros kaki L.) fruit. Three sulphated derivatives with variable degrees of substitution (0.8, 1.7 and 2.5) were obtained by the chlorosulphonic acid-pyridine method. The sulphated derivatives all showed dose-dependent reducing power and free radical scavenging effect of 1,1-dipheny-l-2-picrylhydrazyl, superoxide anion and hydroxyl. Our results showed that the sulphated modification of polysaccharides significantly increased their antioxidant activities and may be an effective way to prepare these valuable derivatives.

  4. Effect of temperature on the hydration of Portland cement blended with siliceous fly ash

    SciTech Connect

    Deschner, Florian; Lothenbach, Barbara; Winnefeld, Frank; Neubauer, Jürgen

    2013-10-15

    The effect of temperature on the hydration of Portland cement pastes blended with 50 wt.% of siliceous fly ash is investigated within a temperature range of 7 to 80 °C. The elevation of temperature accelerates both the hydration of OPC and fly ash. Due to the enhanced pozzolanic reaction of the fly ash, the change of the composition of the C–S–H and the pore solution towards lower Ca and higher Al and Si concentrations is shifted towards earlier hydration times. Above 50 °C, the reaction of fly ash also contributes to the formation of siliceous hydrogarnet. At 80 °C, ettringite and AFm are destabilised and the released sulphate is partially incorporated into the C–S–H. The observed changes of the phase assemblage in dependence of the temperature are confirmed by thermodynamic modelling. The increasingly heterogeneous microstructure at elevated temperatures shows an increased density of the C–S–H and a higher coarse porosity. -- Highlights: •The reaction of quartz powder at 80 °C strongly enhances the compressive strength. •Almost no strength increase of fly ash blended OPC at 80 °C was found after 2 days. •Siliceous hydrogarnet is formed upon the reaction of fly ash at high temperatures. •Temperature dependent change of the system was simulated by thermodynamic modelling. •Destabilisation of ettringite above 50 °C correlates with sulphate content of C–S–H.

  5. Hydration and physical performance.

    PubMed

    Murray, Bob

    2007-10-01

    There is a rich scientific literature regarding hydration status and physical function that began in the late 1800s, although the relationship was likely apparent centuries before that. A decrease in body water from normal levels (often referred to as dehydration or hypohydration) provokes changes in cardiovascular, thermoregulatory, metabolic, and central nervous function that become increasingly greater as dehydration worsens. Similarly, performance impairment often reported with modest dehydration (e.g., -2% body mass) is also exacerbated by greater fluid loss. Dehydration during physical activity in the heat provokes greater performance decrements than similar activity in cooler conditions, a difference thought to be due, at least in part, to greater cardiovascular and thermoregulatory strain associated with heat exposure. There is little doubt that performance during prolonged, continuous exercise in the heat is impaired by levels of dehydration >or= -2% body mass, and there is some evidence that lower levels of dehydration can also impair performance even during relatively short-duration, intermittent exercise. Although additional research is needed to more fully understand low-level dehydration's effects on physical performance, one can generalize that when performance is at stake, it is better to be well-hydrated than dehydrated. This generalization holds true in the occupational, military, and sports settings.

  6. ADR salt pill design and crystal growth process for hydrated magnetic salts

    NASA Technical Reports Server (NTRS)

    Shirron, Peter J. (Inventor); DiPirro, Michael J. (Inventor); Canavan, Edgar R. (Inventor)

    2013-01-01

    A process is provided for producing a salt pill for use in very low temperature adiabatic demagnetization refrigerators (ADRs). The method can include providing a thermal bus in a housing. The thermal bus can include an array of thermally conductive metal conductors. A hydrated salt can be grown on the array of thermally conductive metal conductors. Thermal conductance can be provided to the hydrated salt.

  7. Ductile flow of methane hydrate

    USGS Publications Warehouse

    Durham, W.B.; Stern, L.A.; Kirby, S.H.

    2003-01-01

    Compressional creep tests (i.e., constant applied stress) conducted on pure, polycrystalline methane hydrate over the temperature range 260-287 K and confining pressures of 50-100 MPa show this material to be extraordinarily strong compared to other icy compounds. The contrast with hexagonal water ice, sometimes used as a proxy for gas hydrate properties, is impressive: over the thermal range where both are solid, methane hydrate is as much as 40 times stronger than ice at a given strain rate. The specific mechanical response of naturally occurring methane hydrate in sediments to environmental changes is expected to be dependent on the distribution of the hydrate phase within the formation - whether arranged structurally between and (or) cementing sediments grains versus passively in pore space within a sediment framework. If hydrate is in the former mode, the very high strength of methane hydrate implies a significantly greater strain-energy release upon decomposition and subsequent failure of hydrate-cemented formations than previously expected.

  8. Some thermodynamical aspects of protein hydration water.

    PubMed

    Mallamace, Francesco; Corsaro, Carmelo; Mallamace, Domenico; Vasi, Sebastiano; Vasi, Cirino; Stanley, H Eugene; Chen, Sow-Hsin

    2015-06-01

    We study by means of nuclear magnetic resonance the self-diffusion of protein hydration water at different hydration levels across a large temperature range that includes the deeply supercooled regime. Starting with a single hydration shell (h = 0.3), we consider different hydrations up to h = 0.65. Our experimental evidence indicates that two phenomena play a significant role in the dynamics of protein hydration water: (i) the measured fragile-to-strong dynamic crossover temperature is unaffected by the hydration level and (ii) the first hydration shell remains liquid at all hydrations, even at the lowest temperature.

  9. Some thermodynamical aspects of protein hydration water

    SciTech Connect

    Mallamace, Francesco; Corsaro, Carmelo; Mallamace, Domenico; Vasi, Sebastiano; Vasi, Cirino; Stanley, H. Eugene; Chen, Sow-Hsin

    2015-06-07

    We study by means of nuclear magnetic resonance the self-diffusion of protein hydration water at different hydration levels across a large temperature range that includes the deeply supercooled regime. Starting with a single hydration shell (h = 0.3), we consider different hydrations up to h = 0.65. Our experimental evidence indicates that two phenomena play a significant role in the dynamics of protein hydration water: (i) the measured fragile-to-strong dynamic crossover temperature is unaffected by the hydration level and (ii) the first hydration shell remains liquid at all hydrations, even at the lowest temperature.

  10. Gas Hydrate Petroleum System Analysis

    NASA Astrophysics Data System (ADS)

    Collett, T. S.

    2012-12-01

    In a gas hydrate petroleum system, the individual factors that contribute to the formation of gas hydrate accumulations, such as (1) gas hydrate pressure-temperature stability conditions, (2) gas source, (3) gas migration, and (4) the growth of the gas hydrate in suitable host sediment can identified and quantified. The study of know and inferred gas hydrate accumulations reveal the occurrence of concentrated gas hydrate is mostly controlled by the presence of fractures and/or coarser grained sediments. Field studies have concluded that hydrate grows preferentially in coarse-grained sediments because lower capillary pressures in these sediments permit the migration of gas and nucleation of hydrate. Due to the relatively distal nature of the deep marine geologic settings, the overall abundance of sand within the shallow geologic section is usually low. However, drilling projects in the offshore of Japan, Korea, and in the Gulf of Mexico has revealed the occurrence of significant hydrate-bearing sand reservoirs. The 1999/2000 Japan Nankai Trough drilling confirmed occurrence of hydrate-bearing sand-rich intervals (interpreted as turbidite fan deposits). Gas hydrate was determined to fill the pore spaces in these deposits, reaching saturations up to 80% in some layers. A multi-well drilling program titled "METI Toaki-oki to Kumano-nada" also identified sand-rich reservoirs with pore-filling hydrate. The recovered hydrate-bearing sand layers were described as very-fine- to fine-grained turbidite sand layers measuring from several centimeters up to a meter thick. However, the gross thickness of the hydrate-bearing sand layers were up to 50 m. In 2010, the Republic of Korea conducted the Second Ulleung Basin Gas Hydrate (UBGH2) Drilling Expedition. Seismic data clearly showed the development of a thick, potential basin wide, sedimentary sections characterized by mostly debris flows. The downhole LWD logs and core data from Site UBGH2-5 reveal that each debris flows is

  11. Pilot scale investigation of zinc and sulphate removal from industrial discharges by biological sulphate reduction with molasses as electron donor.

    PubMed

    Liamleam, Warounsak; Oo, Zaw Ko; Thai, Phan Thong; Annachhatre, Ajit P

    2009-11-01

    A biological sulphate reduction process, with molasses as an electron donor, was used for the removal of zinc and sulphate from Rayon industrial wastewater. The process involved reduction of sulphate to sulphide under anaerobic conditions. The sulphide-rich effluent was used to remove zinc as zinc sulphide precipitate. The investigation was conducted at pilot scale with real wastewater from the Rayon industry as feed. The effects of sulphate loading rate and temperature of feeding wastewater were evaluated. The experimental results showed that there was no significant difference in sulphide production when the reactor was operated at 50 +/- 2 degrees C and 65 +/- 2 degrees C. Sulphide production was in the range of 500-515 mg L(-1). In addition, an increase in sulphate loading rate from 6.3 +/- 0.7 kg SO4 m(-3) d(-1) to 14.9 +/- 2.4 kg SO4 m(-3) d(-1) resulted in a dramatic decrease in sulphate removal efficiency. Furthermore, zinc sulphide precipitation at pH 7 removed more than 96% of zinc.

  12. Understanding silicate hydration from quantitative analyses of hydrating tricalcium silicates.

    PubMed

    Pustovgar, Elizaveta; Sangodkar, Rahul P; Andreev, Andrey S; Palacios, Marta; Chmelka, Bradley F; Flatt, Robert J; d'Espinose de Lacaillerie, Jean-Baptiste

    2016-01-01

    Silicate hydration is prevalent in natural and technological processes, such as, mineral weathering, glass alteration, zeolite syntheses and cement hydration. Tricalcium silicate (Ca3SiO5), the main constituent of Portland cement, is amongst the most reactive silicates in water. Despite its widespread industrial use, the reaction of Ca3SiO5 with water to form calcium-silicate-hydrates (C-S-H) still hosts many open questions. Here, we show that solid-state nuclear magnetic resonance measurements of (29)Si-enriched triclinic Ca3SiO5 enable the quantitative monitoring of the hydration process in terms of transient local molecular composition, extent of silicate hydration and polymerization. This provides insights on the relative influence of surface hydroxylation and hydrate precipitation on the hydration rate. When the rate drops, the amount of hydroxylated Ca3SiO5 decreases, thus demonstrating the partial passivation of the surface during the deceleration stage. Moreover, the relative quantities of monomers, dimers, pentamers and octamers in the C-S-H structure are measured. PMID:27009966

  13. Understanding silicate hydration from quantitative analyses of hydrating tricalcium silicates.

    PubMed

    Pustovgar, Elizaveta; Sangodkar, Rahul P; Andreev, Andrey S; Palacios, Marta; Chmelka, Bradley F; Flatt, Robert J; d'Espinose de Lacaillerie, Jean-Baptiste

    2016-03-24

    Silicate hydration is prevalent in natural and technological processes, such as, mineral weathering, glass alteration, zeolite syntheses and cement hydration. Tricalcium silicate (Ca3SiO5), the main constituent of Portland cement, is amongst the most reactive silicates in water. Despite its widespread industrial use, the reaction of Ca3SiO5 with water to form calcium-silicate-hydrates (C-S-H) still hosts many open questions. Here, we show that solid-state nuclear magnetic resonance measurements of (29)Si-enriched triclinic Ca3SiO5 enable the quantitative monitoring of the hydration process in terms of transient local molecular composition, extent of silicate hydration and polymerization. This provides insights on the relative influence of surface hydroxylation and hydrate precipitation on the hydration rate. When the rate drops, the amount of hydroxylated Ca3SiO5 decreases, thus demonstrating the partial passivation of the surface during the deceleration stage. Moreover, the relative quantities of monomers, dimers, pentamers and octamers in the C-S-H structure are measured.

  14. Understanding silicate hydration from quantitative analyses of hydrating tricalcium silicates

    PubMed Central

    Pustovgar, Elizaveta; Sangodkar, Rahul P.; Andreev, Andrey S.; Palacios, Marta; Chmelka, Bradley F.; Flatt, Robert J.; d'Espinose de Lacaillerie, Jean-Baptiste

    2016-01-01

    Silicate hydration is prevalent in natural and technological processes, such as, mineral weathering, glass alteration, zeolite syntheses and cement hydration. Tricalcium silicate (Ca3SiO5), the main constituent of Portland cement, is amongst the most reactive silicates in water. Despite its widespread industrial use, the reaction of Ca3SiO5 with water to form calcium-silicate-hydrates (C-S-H) still hosts many open questions. Here, we show that solid-state nuclear magnetic resonance measurements of 29Si-enriched triclinic Ca3SiO5 enable the quantitative monitoring of the hydration process in terms of transient local molecular composition, extent of silicate hydration and polymerization. This provides insights on the relative influence of surface hydroxylation and hydrate precipitation on the hydration rate. When the rate drops, the amount of hydroxylated Ca3SiO5 decreases, thus demonstrating the partial passivation of the surface during the deceleration stage. Moreover, the relative quantities of monomers, dimers, pentamers and octamers in the C-S-H structure are measured. PMID:27009966

  15. The effect of oral inorganic sulphate on the metabolism of 4-hydroxyphenethylamine (tyramine) in man: tyramine O-sulphate measurement in human urine (Short Communication)

    PubMed Central

    Smith, Ivor; Mitchell, Paul D.

    1974-01-01

    1. Urinary excretion of tyramine O-sulphate in six normal human subjects after an oral dose of 125mg of tyramine hydrochloride alone, and with a supplement of Na2SO4, was determined by using chromatographic and electrophoretic separations followed by spectrophotofluorimetry. 2. In every case the excretion of tyramine O-sulphate was increased significantly after sulphate supplementation. PMID:4441371

  16. Water, Hydration and Health

    PubMed Central

    Popkin, Barry M.; D’Anci, Kristen E.; Rosenberg, Irwin H.

    2010-01-01

    This review attempts to provide some sense of our current knowledge of water including overall patterns of intake and some factors linked with intake, the complex mechanisms behind water homeostasis, the effects of variation in water intake on health and energy intake, weight, and human performance and functioning. Water represents a critical nutrient whose absence will be lethal within days. Water’s importance for prevention of nutrition-related noncommunicable diseases has emerged more recently because of the shift toward large proportions of fluids coming from caloric beverages. Nevertheless, there are major gaps in knowledge related to measurement of total fluid intake, hydration status at the population level, and few longer-term systematic interventions and no published random-controlled longer-term trials. We suggest some ways to examine water requirements as a means to encouraging more dialogue on this important topic. PMID:20646222

  17. Hydrated hydride anion clusters

    NASA Astrophysics Data System (ADS)

    Lee, Han Myoung; Kim, Dongwook; Singh, N. Jiten; Kołaski, Maciej; Kim, Kwang S.

    2007-10-01

    On the basis of density functional theory (DFT) and high level ab initio theory, we report the structures, binding energies, thermodynamic quantities, IR spectra, and electronic properties of the hydride anion hydrated by up to six water molecules. Ground state DFT molecular dynamics simulations (based on the Born-Oppenheimer potential surface) show that as the temperature increases, the surface-bound hydride anion changes to the internally bound structure. Car-Parrinello molecular dynamics simulations are also carried out for the spectral analysis of the monohydrated hydride. Excited-state ab initio molecular dynamics simulations show that the photoinduced charge-transfer-to-solvent phenomena are accompanied by the formation of the excess electron-water clusters and the detachment of the H radical from the clusters. The dynamics of the detachment process of a hydrogen radical upon the excitation is discussed.

  18. Surface charge and growth of sulphate and carbonate green rust in aqueous media

    NASA Astrophysics Data System (ADS)

    Guilbaud, Romain; White, Maggie L.; Poulton, Simon W.

    2013-05-01

    We report the first determination of the point of zero charge of sulphated and carbonated green rust particles. Green rust has been recognised as a prevalent mineral in environments such as hydromorphic soils, groundwaters and anoxic Fe(II)-rich water bodies, and the evolution of its net surface charge with pH has direct implications for the uptake of contaminants, metals and nutrients in such settings. We find that the surface of both sulphated and carbonated green rust is positively charged at pH < 8.3, whereas it is negatively charged at pH > 8.3. Thus, alkaline settings will promote enhanced adsorption of metallic cations. However, the behaviour of ionic species surrounding green rust is more complicated than that predicted by simple pH-dependent adsorption, as our experiments suggest that green rust likely grows via dissolution-reprecipitation during Ostwald-ripening. This implies that adsorbed species are potentially subject to repetitive steps of release into solution, re-adsorption and co-precipitation during particle growth. The growth rate of green rust particles is highest within the first 50 min of aging, and appears to decrease towards an asymptote after 200 min, suggesting that particle growth controls on the uptake of dissolved species will be most important during the early steps of green rust growth. Our findings thus contribute to a better understanding of the controls that green rust may exert on dissolved ions in a variety of anoxic environments.

  19. Process for removing metal contaminants from used lubricating oils

    SciTech Connect

    Johnson, C.B.

    1980-05-27

    A process is provided for removing metal contaminants from used lubricating oil. The used oil is contacted with an aqueous solution of aluminum sulphate and ammonium sulphate at elevated temperature to form compounds of the metal contaminants in an aqueous phase which is phase separable from the oil. An oil product reduced in metal contaminants is thereby produced which is suitable as a cheap fuel or lubricant.

  20. Studies on the metabolism of oestrone sulphate. Comparative perfusions of oestrone and oestrone sulphate through isolated rat livers

    PubMed Central

    Höller, Michael; Grochtmann, Wilhelm; Napp, Mechthild; Breuer, Heinz

    1977-01-01

    The metabolism of [4-14C]oestrone and of [6,7-3H2]oestrone sulphate was studied during cyclic perfusion and once-through perfusion of the isolated rat liver. The following results were obtained. 1. As shown by once-through perfusion, the two steroids are metabolized differently during the first passage through the organ. [4-14C]Oestrone was taken up by the liver and partly delivered as oestradiol-17β and oestriol into the medium. After uptake of [6,7-3H2]oestrone sulphate, only oestrone, liberated by hydrolysis, was delivered into the medium; no oestradiol-17β or oestriol could be detected in the medium after one passage through the organ. This indicates that intracellular oestrone, which was taken up as such, and oestrone, which derived from intracellular hydrolysis, may be metabolized in different compartments of the liver cell. 2. The results of the cyclic perfusion showed that intracellular oestrone is preferentially conjugated with glucuronic acid, and subsequently excreted into the bile. Intracellular oestrone sulphate is preferably reduced to oestradiol sulphate, thus indicating that oestrone sulphate is a better substrate for the 17β-hydroxy steroid oxidoreductase than is oestrone. 3. Albumin-bound oestrone sulphate acts as a large reservoir, and in contrast with free oestrone is protected from enzyme attack by its strong binding to albumin. 4. Oestrone sulphate is partly converted into the hormonally active oestrone by liver tissue. This suggests that liver not only inactivates oestrogens, but also provides the organism with oestrone, which is subsequently readily taken up by other organs. PMID:597232

  1. Comparison of three methods to find the vapor activity of a hydration step.

    PubMed

    Wadsö, L; Markova, N

    2001-01-01

    The formation of a stochiometric salt hydrate takes place at a well defined vapor activity. We have compared three methods to measure this vapor activity. In two of the methods we used a sorption balance in step mode and in ramp mode, respectively, and in one method we used a newly developed sorption microcalorimeter. The tests were made with the formation of morphine sulphate pentahydrate from its dihydrate at 25 degrees C. With all three methods this transition was found to take place at a vapor activity close to 0.21.

  2. Tannery effluent as a carbon source for biological sulphate reduction.

    PubMed

    Boshoff, G; Duncan, J; Rose, P D

    2004-06-01

    Tannery effluent was assessed as a carbon source for biological sulphate reduction in a pilot-scale upflow anaerobic sludge blanket (UASB), stirred tank reactor (STR) and trench reactor (TR). Sulphate removals of between 60-80% were obtained in all three reactors at total sulphate feed levels of up to 1800 mg l(-1). Sulphate removal in the TR (400-500 mg SO4 l(-1) day(-1)) and UASB (up to 600 mg SO4 l(-1) day(-1)) were higher than those obtained in the STR (250 mg SO4 l(1) day(-1)). A change in operation mode from a UASB to a STR had a large impact on chemical oxygen demand (COD) removal efficiencies. COD removal rates decreased by 25% from 600-700 mg COD l(-1) day(-1) to 200-600 mg COD l(-1) day(-1). The TR had an average COD removal rate of 500 mg COD l(-1) day(-1). Large quantities of sulphide were produced in the reactors (up to 1500 mg l(-1)). However due to the elevated pH in the reactor, only a small amount was in the form of H2S and thus the odour problem normally associated with biological sulphate reduction was not present.

  3. Geochemical, metagenomic and metaproteomic insights into trace metal utilization by methane-oxidizing microbial consortia in sulphidic marine sediments.

    PubMed

    Glass, Jennifer B; Yu, Hang; Steele, Joshua A; Dawson, Katherine S; Sun, Shulei; Chourey, Karuna; Pan, Chongle; Hettich, Robert L; Orphan, Victoria J

    2014-06-01

    Microbes have obligate requirements for trace metals in metalloenzymes that catalyse important biogeochemical reactions. In anoxic methane- and sulphide-rich environments, microbes may have unique adaptations for metal acquisition and utilization because of decreased bioavailability as a result of metal sulphide precipitation. However, micronutrient cycling is largely unexplored in cold (≤ 10°C) and sulphidic (> 1 mM ΣH(2)S) deep-sea methane seep ecosystems. We investigated trace metal geochemistry and microbial metal utilization in methane seeps offshore Oregon and California, USA, and report dissolved concentrations of nickel (0.5-270 nM), cobalt (0.5-6 nM), molybdenum (10-5600 nM) and tungsten (0.3-8 nM) in Hydrate Ridge sediment porewaters. Despite low levels of cobalt and tungsten, metagenomic and metaproteomic data suggest that microbial consortia catalysing anaerobic oxidation of methane (AOM) utilize both scarce micronutrients in addition to nickel and molybdenum. Genetic machinery for cobalt-containing vitamin B12 biosynthesis was present in both anaerobic methanotrophic archaea (ANME) and sulphate-reducing bacteria. Proteins affiliated with the tungsten-containing form of formylmethanofuran dehydrogenase were expressed in ANME from two seep ecosystems, the first evidence for expression of a tungstoenzyme in psychrophilic microorganisms. Overall, our data suggest that AOM consortia use specialized biochemical strategies to overcome the challenges of metal availability in sulphidic environments.

  4. Geochemical, metagenomic and metaproteomic insights into trace metal utilization by methane-oxidizing microbial consortia in sulphidic marine sediments

    SciTech Connect

    Glass, DR. Jennifer; Yu, DR. Hang; Steele, Joshua; Dawson, Katherine; Sun, S; Chourey, Karuna; Pan, Chongle; Hettich, Robert {Bob} L; Orphan, V

    2013-01-01

    Microbes have obligate requirements for trace metals in metalloenzymes that catalyse important biogeochemical reactions. In anoxic methane- and sulphiderich environments, microbes may have unique adaptations for metal acquisition and utilization because of decreased bioavailability as a result of metal sulphide precipitation. However, micronutrient cycling is largely unexplored in cold ( 10 C) and sulphidic (> 1 mM H2S) deep-sea methane seep ecosystems. We investigated trace metal geochemistry and microbial metal utilization in methane seeps offshore Oregon and California, USA, and report dissolved concentrations of nickel (0.5 270 nM), cobalt (0.5 6 nM), molybdenum (10 5600 nM) and tungsten (0.3 8 nM) in Hydrate Ridge sediment porewaters. Despite low levels of cobalt and tungsten, metagenomic and metaproteomic data suggest that microbial consortia catalysing anaerobic oxidation of methane (AOM) utilize both scarce micronutrients in addition to nickel and molybdenum. Genetic machinery for cobalt-containing vitamin B12 biosynthesis was present in both anaerobic methanotrophic archaea (ANME) and sulphate-reducing bacteria. Proteins affiliated with the tungsten-containing form of formylmethanofuran dehydrogenase were expressed in ANME from two seep ecosystems, the first evidence for expression of a tungstoenzyme in psychrophilic microorganisms. Overall, our data suggest that AOM consortia use specialized biochemical strategies to overcome the challenges of metal availability in sulphidic environments.

  5. A study on the extent of neutralization of sulphate aerosol through laboratory and field experiments using an ATOFMS and a GPIC

    NASA Astrophysics Data System (ADS)

    Yao, Xiaohong; Rehbein, Peter J. G.; Lee, Colin J.; Evans, Greg J.; Corbin, Joel; Jeong, Cheol-Heon

    2011-11-01

    Extent of neutralization (EoN) of atmospheric aerosol is an important parameter in understanding related nucleation mechanisms, acid-catalyzed reactions and gas-aerosol partitioning. Ion m/ z -195 (HSOHSO4-) detected by the Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) has been used as an indicator of incompletely-neutralized sulphate aerosol, but there are no laboratory data to support this assumption. In this study, experiments using artificially generated sulphuric acid nucleated aerosol and metal sulphate aerosol across a range of EoN found that the peak area ratio and hit ratio of ion m/ z -195 (HSOHSO4-) to ion m/ z -97 (HSO4-) detected by the ATOFMS increased with decreasing EoN. Area ratio and hit ratio are sensitive to EoN at the low and high value zones, respectively. In ambient air measured by the ATOFMS and a Gas Particle Ion Chromatograph (GPIC) in Toronto, Canada, ion m/ z -195 was always detected in ammonium sulphate aerosol, and its hit number and peak area varied widely, regardless of EoN indicated by the equivalent ratio of NH4+ to (SO42-+NO3-). Thus, ion m/ z -195 alone is not an indicator of acidic sulphate aerosol. The combined approach using the ATOFMS and the GPIC found that cloud-processing formed incompletely-neutralized acidic sulphate aerosol in 2 out of 35 days sampled in winter in Toronto, Canada. It is interesting that the two episodes both occurred at night. Formation of incompletely-neutralized acidic sulphate aerosol caused a decrease in the concentration of particulate nitrate. This can be explained by acidic sulphate aerosol reacting with ammonium nitrate, leading to the release of HNO 3 to the gas phase. It was also found that the GPIC results occasionally suffered a positive artifact of NH4+ concentration caused by the clogging-induced high back-pressure in the instrument.

  6. Standard enthalpies of formation of francium hydroxide hydrates

    SciTech Connect

    Burylev, B.P.

    1995-03-01

    Available experimental data on standard enthalpies of formation of alkali metal hydroxide hydrates have been summarized. Using equations derived, the authors have calculated previously unknown enthalpies of formation of some lithium, sodium, potassium, rubidium, and cesium hydroxide hydrates. Taking into account the contribution of water to the enthalpies of formation of monohydrates, the authors have estimated the enthalpies of formation of francium hydroxide hydrates FrOH{center_dot}H{sub 2}O, FrOH{center_dot}2H{sub 2}O, and FrOH{center_dot}3H{sub 2}O (-745.8, -1085.8, and -1515.8 kJ mol{sup -1}, respectively).

  7. Hydration reactions of cement combinations containing vitrified incinerator fly ash

    SciTech Connect

    Dyer, Thomas D.; Dhir, Ravindra K

    2004-05-01

    One treatment option for municipal solid waste incinerator fly ash (IFA) is vitrification. The process yields a material containing reduced levels of trace metals relative to the original ash. The material is glassy and potentially suitable as a cement component in concrete. This paper examines the vitrification of an IFA and studies the hydration reactions of combinations of this vitrified material and Portland cement (PC). Isothermal conduction calorimetry, powder X-ray diffraction (XRD), thermogravimetry (TG) and scanning electron microscopy were employed to study the hydration reactions. As the levels of vitrified ash increase, the quantities of AFt phase produced decrease, whilst quantities of AFm phase increase, due to the reduced levels of sulfate in the vitrified ash. The levels of calcium silicate hydrate (CSH) gel (inferred from estimates of quantities of gel-bound water) remain constant at 28 days regardless of vitrified ash content, indicating that the material is contributing toward the formation of this product.

  8. Reservoir controls on the occurrence and production of gas hydrates in nature

    USGS Publications Warehouse

    Collett, Timothy Scott

    2014-01-01

    modeling has shown that concentrated gas hydrate occurrences in sand reservoirs are conducive to existing well-based production technologies. The resource potential of gas hydrate accumulations in sand-dominated reservoirs have been assessed for several polar terrestrial basins. In 1995, the U.S. Geological Survey (USGS) assigned an in-place resource of 16.7 trillion cubic meters of gas for hydrates in sand-dominated reservoirs on the Alaska North Slope. In a more recent assessment, the USGS indicated that there are about 2.42 trillion cubic meters of technically recoverable gas resources within concentrated, sand-dominated, gas hydrate accumulations in northern Alaska. Estimates of the amount of in-place gas in the sand dominated gas hydrate accumulations of the Mackenzie Delta Beaufort Sea region of the Canadian arctic range from 1.0 to 10 trillion cubic meters of gas. Another prospective gas hydrate resources are those of moderate-to-high concentrations within sandstone reservoirs in marine environments. In 2008, the Bureau of Ocean Energy Management estimated that the Gulf of Mexico contains about 190 trillion cubic meters of gas in highly concentrated hydrate accumulations within sand reservoirs. In 2008, the Japan Oil, Gas and Metals National Corporation reported on a resource assessment of gas hydrates in which they estimated that the volume of gas within the hydrates of the eastern Nankai Trough at about 1.1 trillion cubic meters, with about half concentrated in sand reservoirs. Because conventional production technologies favor sand-dominated gas hydrate reservoirs, sand reservoirs are considered to be the most viable economic target for gas hydrate production and will be the prime focus of most future gas hydrate exploration and development projects.

  9. Obsidian hydration dates glacial loading?

    PubMed

    Friedman, I; Pierce, K L; Obradovich, J D; Long, W D

    1973-05-18

    Three different groups of hydration rinds have been measured on thin sections of obsidian from Obsidian Cliff, Yellowstone National Park, Wyoming. The average thickness of the thickest (oldest) group of hydration rinds is 16.3 micrometers and can be related to the original emplacement of the flow 176,000 years ago (potassium-argon age). In addition to these original surfaces, most thin sections show cracks and surfaces which have average hydration rind thicknesses of 14.5 and 7.9 micrometers. These later two hydration rinds compare closely in thickness with those on obsidian pebbles in the Bull Lake and Pinedale terminal moraines in the West Yellowstone Basin, which are 14 to 15 and 7 to 8 micrometers thick, respectively. The later cracks are thought to have been formed by glacial loading during the Bull Lake and Pinedale glaciations, when an estimated 800 meters of ice covered the Obsidian Cliff flow. PMID:17806883

  10. Proton affinities of hydrated molecules

    NASA Astrophysics Data System (ADS)

    Valadbeigi, Younes

    2016-09-01

    Proton affinities (PA) of non-hydrated, M, and hydrated forms, M(H2O)1,2,3, of 20 organic molecules including alcohols, ethers, aldehydes, ketones and amines were calculated by the B3LYP/6-311++G(d,p) method. For homogeneous families, linear correlations were observed between PAs of the M(H2O)1,2,3 and the PAs of the non-hydrated molecules. Also, the absolute values of the hydration enthalpies of the protonated molecules decreased linearly with the PAs. The correlation functions predicted that for an amine with PA < 1100 kJ/mol the PA(M(H2O)) is larger than the corresponding PA, while for an amine with PA > 1100 kJ/mol the PA(M(H2O)) is smaller than the PA.

  11. Obsidian hydration dates glacial loading?

    PubMed

    Friedman, I; Pierce, K L; Obradovich, J D; Long, W D

    1973-05-18

    Three different groups of hydration rinds have been measured on thin sections of obsidian from Obsidian Cliff, Yellowstone National Park, Wyoming. The average thickness of the thickest (oldest) group of hydration rinds is 16.3 micrometers and can be related to the original emplacement of the flow 176,000 years ago (potassium-argon age). In addition to these original surfaces, most thin sections show cracks and surfaces which have average hydration rind thicknesses of 14.5 and 7.9 micrometers. These later two hydration rinds compare closely in thickness with those on obsidian pebbles in the Bull Lake and Pinedale terminal moraines in the West Yellowstone Basin, which are 14 to 15 and 7 to 8 micrometers thick, respectively. The later cracks are thought to have been formed by glacial loading during the Bull Lake and Pinedale glaciations, when an estimated 800 meters of ice covered the Obsidian Cliff flow.

  12. Obsidian Hydration: A New Paleothermometer

    SciTech Connect

    Anovitz, Lawrence {Larry} M; Riciputi, Lee R; Cole, David R; Fayek, Mostafa; Elam, J. Michael

    2006-01-01

    The natural hydration of obsidian was first proposed as a dating technique for young geological and archaeological specimens by Friedman and Smith (1960), who noted that the thickness of the hydrated layer on obsidian artifacts increases with time. This approach is, however, sensitive to temperature and humidity under earth-surface conditions. This has made obsidian hydration dating more difficult, but potentially provides a unique tool for paleoclimatic reconstructions. In this paper we present the first successful application of this approach, based on combining laboratory-based experimental calibrations with archaeological samples from the Chalco site in the Basin of Mexico, dated using stratigraphically correlated 14C results and measuring hydration depths by secondary ion mass spectrometry. The resultant data suggest, first, that this approach is viable, even given the existing uncertainties, and that a cooling trend occurred in the Basin of Mexico over the past 1450 yr, a result corroborated by other paleoclimatic data.

  13. Obsidian hydration dates glacial loading?

    USGS Publications Warehouse

    Friedman, I.; Pierce, K.L.; Obradovich, J.D.; Long, W.D.

    1973-01-01

    Three different groups of hydration rinds have been measured on thin sections of obsidian from Obsidian Cliff, Yellowstone National Park, Wyoming . The average thickness of the thickest (oldest) group of hydration rinds is 16.3 micrometers and can be related to the original emplacement of the flow 176,000 years ago (potassium-argon age). In addition to these original surfaces, most thin sections show cracks and surfaces which have average hydration rind thicknesses of 14.5 and 7.9 micrometers. These later two hydration rinds compare closely in thickness with those on obsidian pebbles in the Bull Lake and Pinedale terminal moraines in the West Yellowstone Basin, which are 14 to 15 and 7 to 8 micrometers thick, respectively. The later cracks are thought to have been formed by glacial loading during the Bull Lake and Pinedale glaciations, when an estimated 800 meters of ice covered the Obsidian Cliff flow.

  14. The hydration of dental cements.

    PubMed

    Wilson, A D; Paddon, J M; Crisp, S

    1979-03-01

    A study was made of the hydration of dental cements, water being classified as "non-evaporable" and "evaporable". The ratio of these two types of water was found to vary greatly among different cement types, being lesser in zinc oxide and ionic polymer cements and greater in ion-leachable glass and phosphoric acid cements. The cement with the least "non-evaporable" water, i.e., showing least hydration (the zinc polycarboxylate cement), had the lowest strength and modulus and the greatest deformation at failure. A linear relationship was found to exist between strength and the degree of hydration of dental cements. All the cements were found to become more highly hydrated and stronger as they aged. PMID:284040

  15. Conformation and hydration of aspartame.

    PubMed

    Kang, Y K

    1991-07-01

    Conformational free energy calculations using an empirical potential (ECEPP/2) and the hydration shell model were carried out on the neutral, acidic, zwitterionic, and basic forms of aspartame in the hydrated state. The results indicate that as the molecule becomes more charged, the number of low energy conformations becomes smaller and the molecule becomes less flexible. The calculated free energies of hydration of charged aspartames show that hydration has a significant effect on the conformation in solution. Only two feasible conformations were found for the zwitterionic form, and these are consistent with the conformations deduced from NMR and X-ray diffraction experiments. The calculated free energy difference between these two conformations was 1.25 kcal/mol. The less favored of the two solvated conformations can be expected to be stabilized by hydrophobic interaction of the phenyl groups in the crystal.

  16. Influence of H(2) and O(2) on sulphate-reducing activity of a subterranean community and the coupled response in redox potential.

    PubMed

    Pedersen, Karsten

    2012-12-01

    Deep Fennoscandian groundwater is anaerobic, reducing in character and populated by a large diversity of obligate and facultative anaerobic microorganisms. Concentrations of H(2) and carbon monoxide are often 0.01-1 μM and of dissolved organic carbon (DOC) and methane 0.01-1 mM. Microbial activity involving these electron and energy donors may help keep deep groundwater anaerobic and reduced. H(2) was added in concentrations of 0.1-10 mM to a sulphate-reducing community attached to crushed rock in groundwater under a pressure of 2.0 MPa and in situ geochemical conditions. Experiments reported a threshold concentration of approximately 1 μM H(2) at which sulphate reduction ceased, despite the presence of DOC and acetate, suggesting that H(2) was needed for sulphate-reducing activity. δ(13)C values of acetate and DOC data suggested that organic material was degraded to acetate by means of a heterotrophic process. New pressure-resistant micro-sensors for measuring E(h) indicated an H(2)-concentration-dependent decrease in E(h). The investigated community rapidly mitigated the increase in E(h) caused by repeated additions of 0.1-0.2 mM pulses of O(2) as long as H(2) was available. The results imply that sulphate reduction to sulphide with H(2) may dominate sulphate-rich groundwater, which may have implications for metallic underground constructions.

  17. Magnesium sulphate for fetal neuroprotection: a cost-effectiveness analysis

    PubMed Central

    2013-01-01

    Background The aim of this study was to assess the cost-effectiveness of administering magnesium sulphate to patients in whom preterm birth at < 32+0 weeks gestation is either imminent or threatened for the purpose of fetal neuroprotection. Methods Multiple decision tree models and probabilistic sensitivity analyses were used to compare the administration of magnesium sulphate with the alternative of no treatment. Two separate cost perspectives were utilized in this series of analyses: a health system and a societal perspective. In addition, two separate measures of effectiveness were utilized: cases of cerebral palsy (CP) averted and quality-adjusted life years (QALYs). Results From a health system and a societal perspective, respectively, a savings of $2,242 and $112,602 is obtained for each QALY gained and a savings of $30,942 and $1,554,198 is obtained for each case of CP averted when magnesium sulphate is administered to patients in whom preterm birth is imminent. From a health system perspective and a societal perspective, respectively, a cost of $2,083 is incurred and a savings of $108,277 is obtained for each QALY gained and a cost of $28,755 is incurred and a savings of $1,494,500 is obtained for each case of CP averted when magnesium sulphate is administered to patients in whom preterm birth is threatened. Conclusions Administration of magnesium sulphate to patients in whom preterm birth is imminent is a dominant (i.e. cost-effective) strategy, no matter what cost perspective or measure of effectiveness is used. Administration of magnesium sulphate to patients in whom preterm birth is threatened is a dominant strategy from a societal perspective and is very likely to be cost-effective from a health system perspective. PMID:24350635

  18. Microwave assisted synthesis of nano sized sulphate doped hydroxyapatite

    SciTech Connect

    Alshemary, Ammar Z.; Goh, Yi-Fan; Akram, Muhammad; Razali, Ili Rabihah; Abdul Kadir, Mohammed Rafiq; Hussain, Rafaqat

    2013-06-01

    Highlights: ► Phase pure nano-sized sulphur doped hydroxyapatite has been synthesized. ► TEM analysis confirmed formation of needle shaped structure. ► Lattice parameters and cell volume increased with increase in sulphate doping. ► Crystallite size decreased as sulphate content inside the structure increased. ► Degree of crystallinity decreased with increase in sulphate substitution. - Abstract: Inorganic sulphate is required by all mammalian cells to function properly, it is the fourth most abundant anion in the human plasma. Sulphate ions are the major source of sulphur which is considered an important element for sustenance of life as it is present in the essential amino and is required by cells to function properly. In this study we have successfully substituted sulphate ions (SO{sub 4}{sup 2−}) into hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6−x}(SO{sub 4}){sub x}(OH){sub 2−x}) lattice via ion exchange process with phosphate group. Concentration of SO{sub 4}{sup 2−} ions was varied between X = 0.05–0.5, using (Ca (NO{sub 3}){sub 2}·4H{sub 2}O), ((NH{sub 4}){sub 2}HPO{sub 4}) and (Na{sub 2}SO{sub 4}) as starting materials. X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), showed that the substitution of SO{sub 4}{sup 2−} ions into the lattice resulted in peak broadening and reduced peak height due to the amorphous nature and reduced crystallinity of the resulting HA powder. Transmission electron microscopy (TEM) and field emission electron microscopy (FESEM) analysis confirmed the formation of needle shaped particles of 41 nm size with homogenous and uniform distribution of element within the HA structure.

  19. Isolation and quantification of cadmium removal mechanisms in batch reactors inoculated by sulphate reducing bacteria: biosorption versus bioprecipitation.

    PubMed

    Pagnanelli, Francesca; Cruz Viggi, Carolina; Toro, Luigi

    2010-05-01

    Biosorbing properties of sulphate reducing bacteria were tested to distinguish the amount of cadmium removed by bioprecipitation from that bound onto biomass surface (biosorption). Experimental results of cadmium abatement in batch growth tests (bioprecipitation tests) were then compared with metabolism-independent binding properties of SRB cell wall surface (biosorption tests performed with dead biomass). Experimental results showed that SRB inoculum removed 59 + or - 5% of sulphates in 21 days even in presence of cadmium (0-36 mmol L(-1)), while non-monotonous kinetic effects were observed for increasing Cd concentrations. Comparison between bioprecipitation and biosorption tests denoted a significant contribution of biosorption (77%) in total Cd removal (0.40 + or - 0.01 mmol g(-1)). Characterisation of bacterial acid-base surface properties by potentiometric titrations and mechanistic modelling denoted that carboxylic, phosphate and amino groups of cell wall are the main responsible of metal removal by biosorption mechanism.

  20. Airway Hydration and COPD

    PubMed Central

    Ghosh, Arunava; Boucher, R.C.; Tarran, Robert

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is one of the prevalent causes of worldwide mortality and encompasses two major clinical phenotypes, i.e., chronic bronchitis (CB) and emphysema. The most common cause of COPD is chronic tobacco inhalation. Research focused on the chronic bronchitic phenotype of COPD has identified several pathological processes that drive disease initiation and progression. For example, the lung’s mucociliary clearance (MCC) system performs the critical task of clearing inhaled pathogens and toxic materials from the lung. MCC efficiency is dependent on: (i) the ability of apical plasma membrane ion channels such as the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na+ channel (ENaC) to maintain airway hydration; (ii) ciliary beating; and, (iii) appropriate rates of mucin secretion. Each of these components is impaired in CB and likely contributes to the mucus stasis/accumulation seen in CB patients. This review highlights the cellular components responsible for maintaining MCC and how this process is disrupted following tobacco exposure and with CB. We shall also discuss existing therapeutic strategies for the treatment of chronic bronchitis and how components of the MCC can be used as biomarkers for the evaluation of tobacco or tobacco-like-product exposure. PMID:26068443

  1. Microbial colonization in impact-generated hydrothermal sulphate deposits, Haughton impact structure, and implications for sulphates on Mars

    NASA Astrophysics Data System (ADS)

    Parnell, J.; Lee, P.; Cockell, C. S.; Osinski, G. R.

    2004-07-01

    Hydrothermal gypsum deposits in the Haughton impact structure, Devon Island, Canada, contain microbial communities in an endolithic habitat within individual gypsum crystals. Cyanobacterial colonies occur as masses along cleavage planes, up to 5 cm from crystal margins. The crystals are transparent, so allow transmission of light for photosynthesis, while affording protection from dehydration and wind. The colonies appear to have modified their mineral host to provide additional space as they expanded. The colonies are black due to UV-screening pigments. The relative ease with which microbial colonization may be detected and identified in impact-generated sulphate deposits at Haughton suggests that analogous settings on other planets might merit future searches for biosignatures. The proven occurrence of sulphates on the Martian surface suggests that sulphate minerals should be a priority target in the search for life on Mars.

  2. Impacts of Hydrate Pore Habit on Physical Properties of Hydrate Bearing Sediments

    NASA Astrophysics Data System (ADS)

    Seol, Y.; Dai, S.; Choi, J. H.

    2014-12-01

    The physical properties of gas hydrate bearing sediments, to a large extent, are governed by the volume fraction and spatial distribution of the hydrate phase. For sediments containing the same amount of hydrates, their overall physical properties may vary several orders of magnitude depending on hydrate pore habit. We investigate the interplay among hydrate formation methods, hydrate pore habits, and fundamental physical properties of hydrate bearing sediments. We have developed a new method to synthesize noncementing hydrate in sands, a multi-properties characterization chamber to test the hydrate bearing sediments, and pore network models to simulate fluid flow processes in hydrate bearing sediments. We have found that (1) the growth pattern of hydrate crystal in the pore spaces of water saturated sediments is dominated by the relative magnitude of the capillary force (between hydrate crystal and pore fluid) and the skeleton force, which will result in pore-filling or grain-displacing type of hydrate pore character; (2) the existing capillary tube models of water permeability in hydrate bearing sediments are sensitive to pore geometry and hydrate pore habit; and (3) preliminary CT results suggest that hydrate nucleation in partially water saturated sands tends to agglomerate in patches, rather than in an uniformly-distributed contact-cementing morphology. Additional CT results with a small amount of fines (5wt%) and visualization via micro-CT of hydrate pore habits in sediments using different hydrate formation methods will be discussed.

  3. Energy resource potential of natural gas hydrates

    USGS Publications Warehouse

    Collett, T.S.

    2002-01-01

    The discovery of large gas hydrate accumulations in terrestrial permafrost regions of the Arctic and beneath the sea along the outer continental margins of the world's oceans has heightened interest in gas hydrates as a possible energy resource. However, significant to potentially insurmountable technical issues must be resolved before gas hydrates can be considered a viable option for affordable supplies of natural gas. The combined information from Arctic gas hydrate studies shows that, in permafrost regions, gas hydrates may exist at subsurface depths ranging from about 130 to 2000 m. The presence of gas hydrates in offshore continental margins has been inferred mainly from anomalous seismic reflectors, known as bottom-simulating reflectors, that have been mapped at depths below the sea floor ranging from about 100 to 1100 m. Current estimates of the amount of gas in the world's marine and permafrost gas hydrate accumulations are in rough accord at about 20,000 trillion m3. Disagreements over fundamental issues such as the volume of gas stored within delineated gas hydrate accumulations and the concentration of gas hydrates within hydrate-bearing strata have demonstrated that we know little about gas hydrates. Recently, however, several countries, including Japan, India, and the United States, have launched ambitious national projects to further examine the resource potential of gas hydrates. These projects may help answer key questions dealing with the properties of gas hydrate reservoirs, the design of production systems, and, most important, the costs and economics of gas hydrate production.

  4. Chronic barium intoxication disrupts sulphated proteoglycan synthesis: a hypothesis for the origins of multiple sclerosis.

    PubMed

    Purdey, Mark

    2004-01-01

    High level contamination by natural and industrial sources of the alkali earth metal, barium (Ba) has been identified in the ecosystems/workplaces that are associated with high incidence clustering of multiple sclerosis (MS) and other neurodegenerative diseases such as the transmissible spongiform encephalopathies (TSEs) and amyotrophic lateral sclerosis (ALS). Analyses of ecosystems supporting the most renowned MS clusters in Saskatchewan, Sardinia, Massachusetts, Colorado, Guam, NE Scotland demonstrated consistently elevated levels of Ba in soils (mean: 1428 ppm) and vegetation (mean: 74 ppm) in relation to mean levels of 345 and 19 ppm recorded in MS-free regions adjoining. The high levels of Ba stemmed from local quarrying for Ba ores and/or use of Ba in paper/foundry/welding/textile/oil and gas well related industries, as well as from the use of Ba as an atmospheric aerosol spray for enhancing/refracting the signalling of radio/radar waves along military jet flight paths, missile test ranges, etc. It is proposed that chronic contamination of the biosystem with the reactive types of Ba salts can initiate the pathogenesis of MS; due to the conjugation of Ba with free sulphate, which subsequently deprives the endogenous sulphated proteoglycan molecules (heparan sulfates) of their sulphate co partner, thereby disrupting synthesis of S-proteoglycans and their crucial role in the fibroblast growth factor (FGF) signalling which induces oligodendrocyte progenitors to maintain the growth and structural integrity of the myelin sheath. Loss of S-proteoglycan activity explains other key facets of MS pathogenesis; such as the aggregation of platelets and the proliferation of superoxide generated oxidative stress. Ba intoxications disturb the sodium-potassium ion pump--another key feature of the MS profile. The co-clustering of various neurodegenerative diseases in these Ba-contaminated ecosystems suggests that the pathogenesis of all of these diseases could pivot upon a

  5. Chronic barium intoxication disrupts sulphated proteoglycan synthesis: a hypothesis for the origins of multiple sclerosis.

    PubMed

    Purdey, Mark

    2004-01-01

    High level contamination by natural and industrial sources of the alkali earth metal, barium (Ba) has been identified in the ecosystems/workplaces that are associated with high incidence clustering of multiple sclerosis (MS) and other neurodegenerative diseases such as the transmissible spongiform encephalopathies (TSEs) and amyotrophic lateral sclerosis (ALS). Analyses of ecosystems supporting the most renowned MS clusters in Saskatchewan, Sardinia, Massachusetts, Colorado, Guam, NE Scotland demonstrated consistently elevated levels of Ba in soils (mean: 1428 ppm) and vegetation (mean: 74 ppm) in relation to mean levels of 345 and 19 ppm recorded in MS-free regions adjoining. The high levels of Ba stemmed from local quarrying for Ba ores and/or use of Ba in paper/foundry/welding/textile/oil and gas well related industries, as well as from the use of Ba as an atmospheric aerosol spray for enhancing/refracting the signalling of radio/radar waves along military jet flight paths, missile test ranges, etc. It is proposed that chronic contamination of the biosystem with the reactive types of Ba salts can initiate the pathogenesis of MS; due to the conjugation of Ba with free sulphate, which subsequently deprives the endogenous sulphated proteoglycan molecules (heparan sulfates) of their sulphate co partner, thereby disrupting synthesis of S-proteoglycans and their crucial role in the fibroblast growth factor (FGF) signalling which induces oligodendrocyte progenitors to maintain the growth and structural integrity of the myelin sheath. Loss of S-proteoglycan activity explains other key facets of MS pathogenesis; such as the aggregation of platelets and the proliferation of superoxide generated oxidative stress. Ba intoxications disturb the sodium-potassium ion pump--another key feature of the MS profile. The co-clustering of various neurodegenerative diseases in these Ba-contaminated ecosystems suggests that the pathogenesis of all of these diseases could pivot upon a

  6. Effects of aluminium sulphate in the mouse liver: similarities to the aging process.

    PubMed

    Stacchiotti, Alessandra; Lavazza, Antonio; Ferroni, Matteo; Sberveglieri, Giorgio; Bianchi, Rossella; Rezzani, Rita; Rodella, Luigi Fabrizio

    2008-04-01

    Aluminium (Al) is a ubiquitous metal that is potentially toxic to the brain. Its effects on other fundamental organs are not completely understood. This morphological in vivo study sought to compare sublethal hepatotoxic changes and Al deposition in adult mice that orally ingested Al sulphate daily for 10 months, in age matched control mice that drank tap water and in senescent mice (24 months old). Livers were examined for collagen deposition using Sirius red and Masson, for iron accumulation using Perls' stain. Light, electron microscopy and morphometry were used to assess fibrosis and vascular changes. Scanning transmission electron microscopy and EDX microanalysis were used to detect in situ elemental Al. Iron deposition, transferrin receptor expression were significantly altered following Al exposure and in the aged liver but were unaffected in age matched control mice. In Al treated mice as in senescent mice, endothelial thickness was increased and porosity was decreased like perisinusoidal actin. Furthermore, Al stimulated the deposition of collagen and laminin, mainly in acinar zones 1 and 3. Pseudocapillarization and periportal laminin in senescent mice were similar to Al treated adult liver. In conclusion, prolonged Al sulphate intake accelerates features of senescence in the adult mice liver.

  7. The hypobranchial mucin of the whelk Buccinum undatum L. The polysaccharide sulphate component.

    PubMed

    Hunt, S; Jevons, F R

    1966-02-01

    1. A polysaccharide sulphate has been isolated from the hypobranchial mucin of the whelk Buccinum undatum. 2. The molecular weight of this polysaccharide, which is a glucan carrying one ester sulphate group per monosaccharide residue, is 1.7x10(5). 3. Some investigations bearing on the location of the ester sulphate groups are reported. 4. The viscosity of the whole mucin has been shown to depend mainly on the glucan sulphate.

  8. The hypobranchial mucin of the whelk Buccinum undatum L. The polysaccharide sulphate component

    PubMed Central

    Hunt, S.; Jevons, F. R.

    1966-01-01

    1. A polysaccharide sulphate has been isolated from the hypobranchial mucin of the whelk Buccinum undatum. 2. The molecular weight of this polysaccharide, which is a glucan carrying one ester sulphate group per monosaccharide residue, is 1·7×105. 3. Some investigations bearing on the location of the ester sulphate groups are reported. 4. The viscosity of the whole mucin has been shown to depend mainly on the glucan sulphate. PMID:5941346

  9. Microencapsulation of terbutaline sulphate by the solvent evaporation technique.

    PubMed

    Manekar, N C; Puranik, P K; Joshi, S B

    1992-01-01

    Terbutaline sulphate microcapsules were prepared by coacervation-phase separation (solvent evaporation) technique using ethyl cellulose as a coating material. Acetone, ethyl alcohol and isopropyl alcohol were employed as solvents for coating material. Microcapsules were evaluated for their drug content, particle size distribution (microscopic method), flow properties, bulk density, in vitro dissolution, drug release kinetics and surface characteristics (scanning electron microscopy). PMID:1403496

  10. Acute tocolysis for fetal distress: terbutaline versus magnesium sulphate.

    PubMed

    Magann, E F; Cleveland, R S; Dockery, J R; Chauhan, S P; Martin, J N; Morrison, J C

    1993-11-01

    Forty-six women in active labour who developed fetal distress requiring abdominal delivery were randomized to receive 0.25 mg of terbutaline (subcutaneously) or magnesium sulphate as a 4-g bolus (intravenously) to decrease uterine activity. The terbutaline-treated group in contrast to the magnesium sulphate-treated group had reduced uterine activity as measured by Montevideo units (p < 0.002). This decrease in uterine activity was noted more rapidly in all 23 patients who received terbutaline, 1.8 +/- 0.74 minutes compared to 7.5 +/- 2.1 minutes in the 16 of 23 patients (magnesium sulphate-treated women) in whom a decrease in uterine activity occurred (p < 0.001). Umbilical cord arterial blood pH at delivery was less than 7.20 in only 2 of the 23 patients treated with terbutaline versus 7 of the 23 in the magnesium sulphate-treated group. We conclude that terbutaline is an effective and more rapid-acting tocolytic agent to arrest uterine activity prior to delivery for fetal distress. PMID:8179541

  11. Impact of tropospheric sulphate aerosols on the terrestrial carbon cycle

    NASA Astrophysics Data System (ADS)

    Eliseev, Alexey V.

    2015-01-01

    Tropospheric sulphate aerosols (TSAs) may oxidise the photosynthesising tissues if they are taken up by plants. A parameterisation of this impact of tropospheric sulphate aerosols (TSAs) on the terrestrial gross primary production is suggested. This parameterisation is implemented into the global Earth system model developed at the A.M. Obukhov Institute of the Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM). With this coupled model, the simulations are performed which are forced by common anthropogenic and natural climate forcings based on historical reconstructions followed by the RCP 8.5 scenario. The model response to sulphate aerosol loading is subdivided into the climatic (related to the influence of TSA on the radiative transport in the atmosphere) and ecological (related to the toxic influence of sulphate aerosol on terrestrial plants) impacts. We found that the former basically dominates over the latter on a global scale and modifies the responses of the global vegetation and soil carbon stocks to external forcings by 10%. At a regional scale, however, ecological impact may be as much important as the climatic one.

  12. NATURAL GAS HYDRATES STORAGE PROJECT PHASE II. CONCEPTUAL DESIGN AND ECONOMIC STUDY

    SciTech Connect

    R.E. Rogers

    1999-09-27

    DOE Contract DE-AC26-97FT33203 studied feasibility of utilizing the natural-gas storage property of gas hydrates, so abundantly demonstrated in nature, as an economical industrial process to allow expanded use of the clean-burning fuel in power plants. The laboratory work achieved breakthroughs: (1) Gas hydrates were found to form orders of magnitude faster in an unstirred system with surfactant-water micellar solutions. (2) Hydrate particles were found to self-pack by adsorption on cold metal surfaces from the micellar solutions. (3) Interstitial micellar-water of the packed particles were found to continue forming hydrates. (4) Aluminum surfaces were found to most actively collect the hydrate particles. These laboratory developments were the bases of a conceptual design for a large-scale process where simplification enhances economy. In the design, hydrates form, store, and decompose in the same tank in which gas is pressurized to 550 psi above unstirred micellar solution, chilled by a brine circulating through a bank of aluminum tubing in the tank employing gas-fired refrigeration. Hydrates form on aluminum plates suspended in the chilled micellar solution. A low-grade heat source, such as 110 F water of a power plant, circulates through the tubing bank to release stored gas. The design allows a formation/storage/decomposition cycle in a 24-hour period of 2,254,000 scf of natural gas; the capability of multiple cycles is an advantage of the process. The development costs and the user costs of storing natural gas in a scaled hydrate process were estimated to be competitive with conventional storage means if multiple cycles of hydrate storage were used. If more than 54 cycles/year were used, hydrate development costs per Mscf would be better than development costs of depleted reservoir storage; above 125 cycles/year, hydrate user costs would be lower than user costs of depleted reservoir storage.

  13. Oral chondroprotection with nutraceuticals made of chondroitin sulphate plus glucosamine sulphate in osteoarthritis.

    PubMed

    Bottegoni, Carlo; Muzzarelli, Riccardo A A; Giovannini, Francesca; Busilacchi, Alberto; Gigante, Antonio

    2014-08-30

    Oral supplementation of chondroitin sulphate plus glucosamine helps repair the articular surface in osteoarthritis. Chondroitin-S reduces the concentration of the pro-inflammatory cytokines and transcription factor involved in inflammation. GlcN.S enhances cartilage specific matrix components and prevents collagen degeneration in chondrocytes by inhibiting hydrolytic enzymes, and preventing the oxidation of lipids and proteins. Chondroitin-S plus GlcN.S are slow-acting drugs that alleviate pain and partly restore joint function in OA patients. Orally administered pharmaceutical-grade chondroitin-S plus GlcN.S stabilize the joint space narrowing and significantly decrease the number of patients with new erosive OA. They are safe and no adverse events have ever been reported; they are recommended by EULAR and OARSI. The cost/effectiveness of the oral chondroitin-S plus GlcN.S therapy derives from the reduction of costs for physiotherapy, and for gastroprotective and non-steroidal drugs. The synergistic association of these two world-widely preferred nutraceuticals is a step forward in the management of OA. PMID:24815409

  14. Monitoring structural transformation of hydroxy-sulphate green rust in the presence of sulphate reducing bacteria

    NASA Astrophysics Data System (ADS)

    Abdelmoula, M.; Zegeye, A.; Jorand, F.; Carteret, C.

    The activities of bacterial consortia enable organisms to maximize their metabolic capabilities. This article assesses the synergetic relationship between iron reducing bacteria (IRB), Shewanella putrefaciens and sulphate reducing bacteria (SRB) Desulfovibrio alaskensis. Thus, the aim of this study was first to form a biogenic hydroxysulpahte green rust GR2(SO{4/2-}) through the bioreduction of lepidocrocite by S. putrefaciens and secondly to investigate if sulfate anions intercalated in the biogenic GR2(SO{4/2-}) could serve as final electron acceptor for a sulfate reducing bacterium, D. alaskensis. The results indicate that the IRB lead to the formation of GR2(SO{4/2-}) and this mineral serve as an electron acceptor for SRB. GR2(SO{4/2-}) precipitation and its transformation was demonstrated by using X-ray diffraction (DRX), Mössbauer spectroscopy (TMS) and transmission electron spectroscopy (TEM). These observations point out the possible acceleration of steel corrosion in marine environment in presence of IRB/SRB consortia.

  15. Monitoring structural transformation of hydroxy-sulphate green rust in the presence of sulphate reducing bacteria

    NASA Astrophysics Data System (ADS)

    Abdelmoula, M.; Zegeye, A.; Jorand, F.; Carteret, C.

    2006-01-01

    The activities of bacterial consortia enable organisms to maximize their metabolic capabilities. This article assesses the synergetic relationship between iron reducing bacteria (IRB), Shewanella putrefaciens and sulphate reducing bacteria (SRB) Desulfovibrio alaskensis. Thus, the aim of this study was first to form a biogenic hydroxy-sulpahte green rust GR2( {text{SO}}_{{text{4}}} ^{{2 - }} ) through the bioreduction of lepidocrocite by S. putrefaciens and secondly to investigate if sulfate anions intercalated in the biogenic GR2( {text{SO}}_{{text{4}}} ^{{2 - }} ) could serve as final electron acceptor for a sulfate reducing bacterium, D. alaskensis. The results indicate that the IRB lead to the formation of GR2( {text{SO}}_{{text{4}}} ^{{2 - }} ) and this mineral serve as an electron acceptor for SRB. GR2( {text{SO}}_{{text{4}}} ^{{2 - }} ) precipitation and its transformation was demonstrated by using X-ray diffraction (DRX), Mössbauer spectroscopy (TMS) and transmission electron spectroscopy (TEM). These observations point out the possible acceleration of steel corrosion in marine environment in presence of IRB/SRB consortia.

  16. Complex influence of dermatan sulphate on breast cancer cells.

    PubMed

    Koźma, Ewa M; Wisowski, Grzegorz; Latocha, Małgorzata; Kusz, Damian; Olczyk, Krystyna

    2014-12-01

    Tumor transformation and progression both lead to extracellular matrix remodeling, which is also reflected in an alteration in the proportion of dermatan sulphate (DS) and chondroitin sulphate (CS) and an accumulation of the latter. In addition, a significant increase in the 6-O-sulphated disaccharide contribution to the structure of both glycosaminoglycans has been observed. It is commonly accepted that CS is more permissive for tumor growth than DS. However, the detailed role of DS in tumor progression is poorly known. We tested the effects of structurally different DSs on the behavior of cultured breast cancer cells. At a high dose (10 µg/mL), all of the DSs significantly reduced cancer cell growth, although some differences in the efficiency of action were apparent. In contrast, when used at a concentration of 1 µg/mL, the examined DSs evoked different responses ranging from the stimulation to the inhibition of cancer cell proliferation. The highest stimulatory activity was associated with fibrosis-affected fascia decorin DS, which is characterized by a particularly high content of 6-O-sulphated disaccharides. Further reduction in DS concentration to 0.5 µg/mL preserved majority of biological effects which were apparent at a dose of 1 µg/mL. The enzymatic fragmentation of the DSs, particularly by chondroitinase AC I, abolished the impact exerted by 1 µg/mL of the intact DS chains and sometimes resulted in the opposite effect. In contrast to DSs, highly sulphated C-6-S exhibited no effect on the cancer cells. Our data revealed the complexity of the effects of DSs on breast cancer cells, which include both co-receptor activity and the prevention of vascular endothelial growth factor action. In addition, the biological effect of DSs is strongly dependent not only on the glycosaminoglycan structure but also on its content in the cancer environment.

  17. Making solutions from hydrated compounds.

    PubMed

    Adams, Dany Spencer

    2008-05-01

    INTRODUCTIONSolution making typically involves dissolving dry chemicals in water or other specified solvent. The amount of chemical to be added to a solvent depends on the final concentration or molarity (M) needed for the finished solution and the total amount in liters (L) of solution required. However, some chemicals come with water molecules attached. The molecular weight (MW) of such compounds, listed as formula weight (FW) on the bottle, includes the mass of the water. Whenever you would use the MW of an unhydrated compound in calculations, use instead the MW of the hydrated compound. If a recipe tells how many grams to use of the unhydrated compound, determine the target concentration and then calculate the grams to use of hydrated compound. When using a hydrated compound, the attached water molecules contribute water to the solution, potentially diluting the final concentration (if the solvent is water). Therefore, you must account for the contribution of water from the hydrated compound when determining the volume of solvent (water) to add. This article describes the calculations involved in making solutions from hydrated compounds.

  18. Demonstration of immunogenic keratan sulphate in commercial chondroitin 6-sulphate from shark cartilage. Implications for ELISA assays.

    PubMed

    Møller, H J; Møller-Pedersen, T; Damsgaard, T E; Poulsen, J H

    1995-05-15

    The prototype monoclonal keratan sulphate (KS) antibody 5D4 that is widely used for detection of KS in tissues and biological fluids reacts strongly with commercial low grade shark cartilage chondroitin 6-sulphate. Characterization of the immunogenic material by chondroitinase ABC digestion, ELISA inhibition studies, immunoblotting and HPLC analyses confirmed the presence of substantial amounts of KS, probably as a large proteoglycan (> 120 kDa). Commercial and heterogenic glycosaminoglycan preparations therefore must be used with great caution in immunological analyses. On the other hand the shark cartilage chondroitin 6-sulphate is an easy accessible source of immunogenic KS that can be used as a reference standard and as coating antigen in KS-ELISAs. The concentration of immunogenic KS in synovial fluid measured with an ELISA based solely on reagents of shark cartilage chondroitin 6-sulphate correlated well (r = 0.90) with the concentrations obtained with a traditional KS-ELISA that uses purified aggrecan as standard and coating antigen, and KS in both serum and synovial fluid could be measured with sufficient linearity.

  19. A Sea Floor Methane Hydrate Displacement Experiment Using N2 Gas

    NASA Astrophysics Data System (ADS)

    Brewer, P. G.; Peltzer, E. T.; Walz, P. M.; Zhang, X.; Hester, K.

    2009-12-01

    The production of free methane gas from solid methane hydrate accumulations presents a considerable challenge. The presently preferred procedure is pressure reduction whereby the relief of pressure to a condition outside the hydrate phase boundary creates a gas phase. The reaction is endothermic and thus a problematic water ice phase can form if the extraction of gas is too rapid, limiting the applicability of this procedure. Additionally, the removal of the formation water in contact with the hydrate phase is required before meaningful pressure reduction can be attained -- and this can take time. An alternate approach that has been suggested is the injection of liquid CO2 into the formation, thereby displacing the formation water. Formation of a solid CO2 hydrate is thermodynamically favored under these conditions. Competition between CH4 and CO2 for the hydrate host water molecules can occur displacing CH4 from the solid to the gas phase with formation of a solid CO2 hydrate. We have investigated another alternate approach with displacement of the surrounding bulk water phase by N2 gas, resulting in rapid release of CH4 gas and complete loss of the solid hydrate phase. Our experiment was carried out at the Southern Summit of Hydrate Ridge, offshore Oregon, at 780m depth. There we harvested hydrate fragments from surficial sediments using the robotic arm of the ROV Doc Ricketts. Specimens of the hydrate were collected about 1m above the sediment surface in an inverted funnel with a mesh covered neck as they floated upwards. The accumulated hydrate was transferred to an inverted glass cylinder, and N2 gas was carefully injected into this container. Displacement of the water phase occurred and when the floating hydrate material approached the lower rim the gas injection was stopped and the cylinder placed upon a flat metal plate effectively sealing the system. We returned to this site after 7 days to measure progress, and observed complete loss of the hydrate phase

  20. Well log evaluation of natural gas hydrates

    SciTech Connect

    Collett, T.S.

    1992-10-01

    Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question linking gas hydrate resource and hazard issues is: What is the volume of gas hydrates and included gas within a given gas hydrate occurrence? Most published gas hydrate resource estimates have, of necessity, been made by broad extrapolation of only general knowledge of local geologic conditions. Gas volumes that may be attributed to gas hydrates are dependent on a number of reservoir parameters, including the areal extent ofthe gas-hydrate occurrence, reservoir thickness, hydrate number, reservoir porosity, and the degree of gas-hydrate saturation. Two of the most difficult reservoir parameters to determine are porosity and degreeof gas hydrate saturation. Well logs often serve as a source of porosity and hydrocarbon saturation data; however, well-log calculations within gas-hydrate-bearing intervals are subject to error. The primary reason for this difficulty is the lack of quantitative laboratory and field studies. The primary purpose of this paper is to review the response of well logs to the presence of gas hydrates.

  1. Well log evaluation of natural gas hydrates

    SciTech Connect

    Collett, T.S.

    1992-10-01

    Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question linking gas hydrate resource and hazard issues is: What is the volume of gas hydrates and included gas within a given gas hydrate occurrence Most published gas hydrate resource estimates have, of necessity, been made by broad extrapolation of only general knowledge of local geologic conditions. Gas volumes that may be attributed to gas hydrates are dependent on a number of reservoir parameters, including the areal extent ofthe gas-hydrate occurrence, reservoir thickness, hydrate number, reservoir porosity, and the degree of gas-hydrate saturation. Two of the most difficult reservoir parameters to determine are porosity and degreeof gas hydrate saturation. Well logs often serve as a source of porosity and hydrocarbon saturation data; however, well-log calculations within gas-hydrate-bearing intervals are subject to error. The primary reason for this difficulty is the lack of quantitative laboratory and field studies. The primary purpose of this paper is to review the response of well logs to the presence of gas hydrates.

  2. Hydrated interfacial ions and electrons.

    PubMed

    Abel, Bernd

    2013-01-01

    Charged particles such as hydrated ions and transient hydrated electrons, the simplest anionic reducing agents in water, and the special hydronium and hydroxide ions at water interfaces play an important role in many fields of science, such as atmospheric chemistry, radiation chemistry, and biology, as well as biochemistry. This article focuses on these species near hydrophobic interfaces of water, such as the air or vacuum interface of water or water protein/membrane interfaces. Ions at interfaces as well as solvated electrons have been reviewed frequently during the past decade. Although all species have been known for some time with seemingly familiar features, recently the picture in all cases became increasingly diffuse rather than clearer. The current account gives a critical state-of-the art overview of what is known and what remains to be understood and investigated about hydrated interfacial ions and electrons.

  3. Rheology of hydrate forming emulsions.

    PubMed

    Peixinho, Jorge; Karanjkar, Prasad U; Lee, Jae W; Morris, Jeffrey F

    2010-07-20

    Results are reported on an experimental study of the rheology of hydrate-forming water-in-oil emulsions. Density-matched concentrated emulsions were quenched by reducing the temperature and an irreversible transition was observed where the viscosity increased dramatically. The hydrate-forming emulsions have characteristic times for abrupt viscosity change dependent only on the temperature, reflecting the importance of the effect of subcooling. Mechanical transition of hydrate-free water-in-oil emulsions may require longer times and depends on the shear rate, occurring more rapidly at higher rates but with significant scatter which is characterized through a probabilistic analysis. This rate dependence together with dependence on subcooling reflects the importance of hydrodynamic forces to bring drops or particles together.

  4. A Post-Genomic View of the Ecophysiology, Catabolism and Biotechnological Relevance of Sulphate-Reducing Prokaryotes.

    PubMed

    Rabus, Ralf; Venceslau, Sofia S; Wöhlbrand, Lars; Voordouw, Gerrit; Wall, Judy D; Pereira, Inês A C

    2015-01-01

    Dissimilatory sulphate reduction is the unifying and defining trait of sulphate-reducing prokaryotes (SRP). In their predominant habitats, sulphate-rich marine sediments, SRP have long been recognized to be major players in the carbon and sulphur cycles. Other, more recently appreciated, ecophysiological roles include activity in the deep biosphere, symbiotic relations, syntrophic associations, human microbiome/health and long-distance electron transfer. SRP include a high diversity of organisms, with large nutritional versatility and broad metabolic capacities, including anaerobic degradation of aromatic compounds and hydrocarbons. Elucidation of novel catabolic capacities as well as progress in the understanding of metabolic and regulatory networks, energy metabolism, evolutionary processes and adaptation to changing environmental conditions has greatly benefited from genomics, functional OMICS approaches and advances in genetic accessibility and biochemical studies. Important biotechnological roles of SRP range from (i) wastewater and off gas treatment, (ii) bioremediation of metals and hydrocarbons and (iii) bioelectrochemistry, to undesired impacts such as (iv) souring in oil reservoirs and other environments, and (v) corrosion of iron and concrete. Here we review recent advances in our understanding of SRPs focusing mainly on works published after 2000. The wealth of publications in this period, covering many diverse areas, is a testimony to the large environmental, biogeochemical and technological relevance of these organisms and how much the field has progressed in these years, although many important questions and applications remain to be explored.

  5. A Post-Genomic View of the Ecophysiology, Catabolism and Biotechnological Relevance of Sulphate-Reducing Prokaryotes.

    PubMed

    Rabus, Ralf; Venceslau, Sofia S; Wöhlbrand, Lars; Voordouw, Gerrit; Wall, Judy D; Pereira, Inês A C

    2015-01-01

    Dissimilatory sulphate reduction is the unifying and defining trait of sulphate-reducing prokaryotes (SRP). In their predominant habitats, sulphate-rich marine sediments, SRP have long been recognized to be major players in the carbon and sulphur cycles. Other, more recently appreciated, ecophysiological roles include activity in the deep biosphere, symbiotic relations, syntrophic associations, human microbiome/health and long-distance electron transfer. SRP include a high diversity of organisms, with large nutritional versatility and broad metabolic capacities, including anaerobic degradation of aromatic compounds and hydrocarbons. Elucidation of novel catabolic capacities as well as progress in the understanding of metabolic and regulatory networks, energy metabolism, evolutionary processes and adaptation to changing environmental conditions has greatly benefited from genomics, functional OMICS approaches and advances in genetic accessibility and biochemical studies. Important biotechnological roles of SRP range from (i) wastewater and off gas treatment, (ii) bioremediation of metals and hydrocarbons and (iii) bioelectrochemistry, to undesired impacts such as (iv) souring in oil reservoirs and other environments, and (v) corrosion of iron and concrete. Here we review recent advances in our understanding of SRPs focusing mainly on works published after 2000. The wealth of publications in this period, covering many diverse areas, is a testimony to the large environmental, biogeochemical and technological relevance of these organisms and how much the field has progressed in these years, although many important questions and applications remain to be explored. PMID:26210106

  6. Calcium-aluminum-silicate-hydrate "cement" phases and rare Ca-zeolite association at Colle Fabbri, Central Italy

    NASA Astrophysics Data System (ADS)

    Stoppa, F.; Scordari, F.; Mesto, E.; Sharygin, V. V.; Bortolozzi, G.

    2010-06-01

    Very high temperature, Ca-rich alkaline magma intruded an argillite formation at Colle Fabbri, Central Italy, producing cordierite-tridymite metamorphism in the country rocks. An intense Ba-rich sulphate-carbonate-alkaline hydrothermal plume produced a zone of mineralization several meters thick around the igneous body. Reaction of hydrothermal fluids with country rocks formed calcium-silicate-hydrate (CSH), i.e., tobermorite-afwillite-jennite; calcium-aluminum-silicate-hydrate (CASH) — "cement" phases - i.e., thaumasite, strätlingite and an ettringite-like phase and several different species of zeolites: chabazite-Ca, willhendersonite, gismon-dine, three phases bearing Ca with the same or perhaps lower symmetry of phillipsite-Ca, levyne-Ca and the Ca-rich analogue of merlinoite. In addition, apophyllite-(KF) and/or apophyllite-(KOH), Ca-Ba-carbonates, portlandite and sulphates were present. A new polymorph from the pyrrhotite group, containing three layers of sphalerite-type structure in the unit cell, is reported for the first time. Such a complex association is unique. Most of these minerals are specifically related to hydration processes of: (1) pyrometamorphic metacarbonate/metapelitic rocks (natural analogues of cement clinkers); (2) mineralization between intrusive stocks and slates; and (3) high-calcium, alkaline igneous rocks such as melilitites and foidites as well as carbonatites. The Colle Fabbri outcrop offers an opportunity to study in situ complex crystalline overgrowth and specific crystal chemistry in mineral phases formed in igneous to hydrothermal conditions.

  7. High-field n.m.r. studies of keratan sulphates. 1H and 13C assignments of keratan sulphate from shark cartilage.

    PubMed

    Cockin, G H; Huckerby, T N; Nieduszynski, I A

    1986-06-15

    Keratan sulphate was extracted from a shark/whale cartilage preparation and examined by 400 MHz 1H- and 100 MHz 13C-n.m.r. spectroscopy. Assignment of the majority of the resonances was facilitated by two-dimensional 13C-1H correlation by using a modified COLOC procedure and a COSY-45 experiment. The spectra are consistent with an N-acetyl-lactosamine repeating unit that is predominantly sulphated at C-6 of both galactose and N-acetylglucosamine. Gel chromatography of a keratanase digest of the shark keratan sulphate confirmed the high degree of galactose sulphation.

  8. Gas Hydrate and Pore Pressure

    NASA Astrophysics Data System (ADS)

    Tinivella, Umberta; Giustiniani, Michela

    2014-05-01

    Many efforts have been devoted to quantify excess pore pressures related to gas hydrate dissociation in marine sediments below the BSR using several approaches. Dissociation of gas hydrates in proximity of the BSR, in response to a change in the physical environment (i.e., temperature and/or pressure regime), can liberate excess gas incrising the local pore fluid pressure in the sediment, so decreasing the effective normal stress. So, gas hydrate dissociation may lead to excess pore pressure resulting in sediment deformation or failure, such as submarine landslides, sediment slumping, pockmarks and mud volcanoes, soft-sediment deformation and giant hummocks. Moreover, excess pore pressure may be the result of gas hydrate dissociation due to continuous sedimentation, tectonic uplift, sea level fall, heating or inhibitor injection. In order to detect the presence of the overpressure below the BSR, we propose two approachs. The fist approach models the BSR depth versus pore pressure; in fact, if the free gas below the BSR is in overpressure condition, the base of the gas hydrate stability is deeper with respect to the hydrostatic case. This effect causes a discrepancy between seismic and theoretical BSR depths. The second approach models the velocities versus gas hydrate and free gas concentrations and pore pressure, considering the approximation of the Biot theory in case of low frequency, i.e. seismic frequency. Knowing the P and S seismic velocity from seismic data analysis, it is possibile to jointly estimate the gas hydrate and free gas concentrations and the pore pressure regime. Alternatively, if the S-wave velocity is not availbale (due to lack of OBS/OBC data), an AVO analysis can be performed in order to extract information about Poisson ratio. Our modeling suggests that the areas characterized by shallow waters (i.e., areas in which human infrastructures, such as pipelines, are present) are significantly affected by the presence of overpressure condition

  9. Natural Gas Hydrates Update 1998-2000

    EIA Publications

    2001-01-01

    Significant events have transpired on the natural gas hydrate research and development front since "Future Supply Potential of Natural Gas Hydrates" appeared in Natural Gas 1998 Issues and Trends and in the Potential Gas Committee's 1998 biennial report.

  10. Physical properties of hydrate-bearing sediments

    NASA Astrophysics Data System (ADS)

    Waite, W. F.; Santamarina, J. C.; Cortes, D. D.; Dugan, B.; Espinoza, D. N.; Germaine, J.; Jang, J.; Jung, J. W.; Kneafsey, T. J.; Shin, H.; Soga, K.; Winters, W. J.; Yun, T.-S.

    2009-12-01

    Methane gas hydrates, crystalline inclusion compounds formed from methane and water, are found in marine continental margin and permafrost sediments worldwide. This article reviews the current understanding of phenomena involved in gas hydrate formation and the physical properties of hydrate-bearing sediments. Formation phenomena include pore-scale habit, solubility, spatial variability, and host sediment aggregate properties. Physical properties include thermal properties, permeability, electrical conductivity and permittivity, small-strain elastic P and S wave velocities, shear strength, and volume changes resulting from hydrate dissociation. The magnitudes and interdependencies of these properties are critically important for predicting and quantifying macroscale responses of hydrate-bearing sediments to changes in mechanical, thermal, or chemical boundary conditions. These predictions are vital for mitigating borehole, local, and regional slope stability hazards; optimizing recovery techniques for extracting methane from hydrate-bearing sediments or sequestering carbon dioxide in gas hydrate; and evaluating the role of gas hydrate in the global carbon cycle.

  11. Methods to determine hydration states of minerals and cement hydrates

    SciTech Connect

    Baquerizo, Luis G.; Matschei, Thomas; Scrivener, Karen L.; Saeidpour, Mahsa; Thorell, Alva; Wadsö, Lars

    2014-11-15

    This paper describes a novel approach to the quantitative investigation of the impact of varying relative humidity (RH) and temperature on the structure and thermodynamic properties of salts and crystalline cement hydrates in different hydration states (i.e. varying molar water contents). The multi-method approach developed here is capable of deriving physico-chemical boundary conditions and the thermodynamic properties of hydrated phases, many of which are currently missing from or insufficiently reported in the literature. As an example the approach was applied to monosulfoaluminate, a phase typically found in hydrated cement pastes. New data on the dehydration and rehydration of monosulfoaluminate are presented. Some of the methods used were validated with the system Na{sub 2}SO{sub 4}–H{sub 2}O and new data related to the absorption of water by anhydrous sodium sulfate are presented. The methodology and data reported here should permit better modeling of the volume stability of cementitious systems exposed to various different climatic conditions.

  12. How sulphate-reducing microorganisms cope with stress: Lessons from systems biology

    SciTech Connect

    Zhou, J.; He, Q.; Hemme, C.L.; Mukhopadhyay, A.; Hillesland, K.; Zhou, A.; He, Z.; Nostrand, J.D. Van; Hazen, T.C.; Stahl, D.A.; Wall, J.D.; Arkin, A.P.

    2011-04-01

    Sulphate-reducing microorganisms (SRMs) are a phylogenetically diverse group of anaerobes encompassing distinct physiologies with a broad ecological distribution. As SRMs have important roles in the biogeochemical cycling of carbon, nitrogen, sulphur and various metals, an understanding of how these organisms respond to environmental stresses is of fundamental and practical importance. In this Review, we highlight recent applications of systems biology tools in studying the stress responses of SRMs, particularly Desulfovibrio spp., at the cell, population, community and ecosystem levels. The syntrophic lifestyle of SRMs is also discussed, with a focus on system-level analyses of adaptive mechanisms. Such information is important for understanding the microbiology of the global sulphur cycle and for developing biotechnological applications of SRMs for environmental remediation, energy production, biocorrosion control, wastewater treatment and mineral recovery.

  13. Natural gas hydrates; vast resource, uncertain future

    USGS Publications Warehouse

    Collett, T.S.

    2001-01-01

    Gas hydrates are naturally occurring icelike solids in which water molecules trap gas molecules in a cagelike structure known as a clathrate. Although many gases form hydrates in nature, methane hydrate is by far the most common; methane is the most abundant natural gas. The volume of carbon contained in methane hydrates worldwide is estimated to be twice the amount contained in all fossil fuels on Earth, including coal.

  14. Stable isotope fractionation related to technically enhanced bacterial sulphate degradation in lignite mining sediments.

    PubMed

    Knöller, Kay; Jeschke, Christina; Simon, André; Gast, Martin; Hoth, Nils

    2012-01-01

    A mine dump aquifer in the Lusatian lignite mining district, Germany, is contaminated with acid mine drainage (AMD). The only natural process that can counteract the effects of the contamination is bacterial sulphate reduction. The technical measures chosen to handle the contamination include the injection of glycerol into the aquifer to supply electron donors and to accelerate the growth and activity of sulphate-reducing bacteria. An initial assessment of the hydrochemical conditions in the aquifer showed that sulphate concentrations are subject to alteration due to flow-related processes. Consequently, the decision whether sulphate reduction is occurring in the investigated aquifer section was based on the stable isotopic composition of dissolved sulphate and sulphide, which were used in combination with sulphate concentrations. The significant enrichment of both heavy sulphur and heavy oxygen in the remaining sulphate pool and a characteristic isotope fractionation pattern are a clear evidence for the activity of sulphate-reducing bacteria utilising the injected glycerol as an electron donor. This activity seemed to intensify over the observation period. The spatial distribution of sulphate reduction activity, however, appeared to be highly inhomogeneous. Rather than occurring ubiquitously, sulphate reduction activity seemed to concentrate in a defined reaction zone. Regardless of the inhomogeneous distribution, the overall turnover of sulphate during the period of investigation proves the applicability of this enhanced natural attenuation method to handle the restoration of aquifers contaminated with AMD.

  15. Hydration Gibbs free energies of open and closed shell trivalent lanthanide and actinide cations from polarizable molecular dynamics.

    PubMed

    Marjolin, Aude; Gourlaouen, Christophe; Clavaguéra, Carine; Ren, Pengyu Y; Piquemal, Jean-Philip; Dognon, Jean-Pierre

    2014-10-01

    The hydration free energies, structures, and dynamics of open- and closed-shell trivalent lanthanide and actinide metal cations are studied using molecular dynamics simulations (MD) based on a polarizable force field. Parameters for the metal cations are derived from an ab initio bottom-up strategy. MD simulations of six cations solvated in bulk water are subsequently performed with the AMOEBA polarizable force field. The calculated first-and second shell hydration numbers, water residence times, and free energies of hydration are consistent with experimental/theoretical values leading to a predictive modeling of f-elements compounds.

  16. The influence of sulphates on chloride binding and pore solution chemistry

    SciTech Connect

    Xu, Y.

    1997-12-01

    Ordinary Portland cement (OPC) and OPC/ground granulated blast furnace slag (GGBS) 65% cements containing 2.0 to 9.0% sulphates derived from sodium sulphate and calcium sulphate were investigated in respect to their chloride binding properties and the concentrations of chloride and hydroxyl ions in the pore solutions. Chlorides derived from sodium and calcium chlorides were introduced at the time of mixing. The results indicate that calcium sulphate has a different effect on chloride binding and the pore solution chemistry than sodium sulphate. The slag cement has higher chloride binding capacities as a result of simple replacement for OPC, but at the same sulphate contents, the slag cement does not give the expected higher binding capacities, suggesting that the difference in sulphate content between the two cements may be the main reason for their different chloride binding behavior.

  17. The effect of magnesium on partial sulphate removal from mine water as gypsum.

    PubMed

    Tolonen, Emma-Tuulia; Rämö, Jaakko; Lassi, Ulla

    2015-08-15

    The aim of this research was to investigate the effect of magnesium on the removal efficiency of sulphate as gypsum from mine water. The precipitation conditions were simulated with MINEQL + software and the simulation results were compared with the results from laboratory jar test experiments. Both the simulation and the laboratory results showed that magnesium in the mine water was maintaining sulphate in a soluble form as magnesium sulphate (MgSO4) at pH 9.6. Thus magnesium was preventing the removal of sulphate as gypsum (CaSO4·2H2O). However, change in the lime precipitation pH from 9.6 to 12.5 resulted in magnesium hydroxide (Mg(OH)2) precipitation and improved sulphate removal. Additionally, magnesium hydroxide could act as seed crystals for gypsum precipitation or co-precipitate sulphate further enhancing the removal of sulphate from mine water.

  18. Optimization study for Pb(II) and COD sequestration by consortium of sulphate-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Verma, Anamika; Bishnoi, Narsi R.; Gupta, Asha

    2016-04-01

    In this study, initial minimum inhibitory concentration (MIC) of Pb(II) ions was analysed to check optimum concentration of Pb(II) ions at which the growth of sulphate-reducing consortium (SRC) was found to be maximum. 80 ppm of Pb(II) ions was investigated as minimum inhibitory concentration for SRC. Influence of electron donors such as lactose, sucrose, glucose and sodium lactate was examined to investigate best carbon source for growth and activity of sulphate-reducing bacteria. Sodium lactate was found to be the prime carbon source for SRC. Later optimization of various parameters was executed using Box-Behnken design model of response surface methodology to explore the effectiveness of three independent operating variables, namely, pH (5.0-9.0), temperature (32-42 °C) and time (5.0-9.0 days), on dependent variables, i.e. protein content, precipitation of Pb(II) ions, and removal of COD by SRC biomass. Maximum removal of COD and Pb(II) was observed to be 91 and 98 %, respectively, at pH 7.0 and temperature 37 °C and incubation time 7 days. According to response surface analysis and analysis of variance, the experimental data were perfectly fitted to the quadratic model, and the interactive influence of pH, temperature and time on Pb(II) and COD removal was highly significant. A high regression coefficient between the variables and response (r 2 = 0.9974) corroborate eminent evaluation of experimental data by second-order polynomial regression model. SEM and Fourier transform infrared analysis was performed to investigate morphology of PbS precipitates, sorption mechanism and involved functional groups in metal-free and metal-loaded biomass of SRC for Pb(II) binding.

  19. 75 FR 9886 - Methane Hydrate Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Methane... meeting. SUMMARY: This notice announces a meeting of the Methane Hydrate Advisory Committee. Federal... Methane Hydrate Advisory Committee is to provide advice on potential applications of methane hydrate...

  20. Development of the Methane Hydrate Burning Experimental Equipment

    NASA Astrophysics Data System (ADS)

    Aoyama, S.

    2010-12-01

    There is a need to increase understanding among Japanese citizens about the importance as a potential future energy source of the great quantity of methane hydrate deposits sleeping on the sea bed around Japan. With cooperation from the Japan Oil, Gas and Metals National Corporation (JOGMEC), the National Institute of Advanced Industrial Science and Technology (AIST), and the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) we studied the possibility of using presentations where it was possible to handle actual methane hydrate, videos and active presentations such as experiments in order to increase the public interest in and understanding of methane hydrate. Furthermore, for the benefit of those people who would like to visit the exhibition but are unable to do so due to distance or other physical barriers, we looked into making the presentation materials portable and having a moving exhibition. Currently methane hydrate combustion experiments and exhibition performances are being held at the Hidaka Port New Energy Park (The Kansai Electric Power Co., Inc.) in Gobo, Wakayama with approximately 3,000 visitors monthly.

  1. Chitosan hydrogels for chondroitin sulphate controlled release: an analytical characterization.

    PubMed

    Bianchera, Annalisa; Salomi, Enrico; Pezzanera, Matteo; Ruwet, Elisabeth; Bettini, Ruggero; Elviri, Lisa

    2014-01-01

    This paper provides an analytical characterization of chitosan scaffolds obtained by freeze-gelation toward the uptake and the controlled release of chondroitin sulphate (CS), as cartilage repair agent, under different pH conditions. Scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and liquid chromatography-UV spectrophotometry (LC-UV) techniques were exploited to obtain qualitative and quantitative descriptions of polymer and drug behaviour in the biomaterial. As for morphology, SEM analysis allowed the evaluation of scaffold porosity in terms of pore size and distribution both at the surface (Feret diameter 58 ± 19 μm) and on the cross section (Feret diameter 106 ± 51 μm). LC and ATR-FTIR evidenced a pH-dependent CS loading and release behaviour, strongly highlighting the role of electrostatic forces on chitosan/chondroitin sulphate interactions. PMID:25614850

  2. Hydration rind dates rhyolite flows.

    PubMed

    Friedman, I

    1968-02-23

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago. PMID:17768978

  3. Attraction between hydrated hydrophilic surfaces

    NASA Astrophysics Data System (ADS)

    Kanduč, Matej; Schneck, Emanuel; Netz, Roland R.

    2014-08-01

    According to common knowledge, hydrophilic surfaces repel via hydration forces while hydrophobic surfaces attract, but mounting experimental evidence suggests that also hydrophilic surfaces can attract. Using all-atom molecular dynamics simulations at prescribed water chemical potential we study the crossover from hydration repulsion to hydrophobic attraction for planar polar surfaces of varying stiffness and hydrogen-bonding capability. Rescaling the partial charges of the polar surface groups, we cover the complete spectrum from very hydrophobic surfaces (characterized by contact angles θ ≃ 135°) to hydrophilic surfaces exhibiting complete wetting (θ = 0°). Indeed, for a finite range θadh < θ < 90°, we find a regime where hydrophilic surfaces attract at sub-nanometer separation and stably adhere without intervening water. The adhesive contact angle θadh depends on surface type and lies in the range 65° < θadh < 80°, in good agreement with experiments. Analysis of the total number of hydrogen bonds (HBs) formed by water and surface groups rationalizes this crossover between hydration repulsion and hydrophilic attraction in terms of a subtle balance: Highly polar surfaces repel because of strongly bound hydration water, less polar hydrophilic surfaces attract because water-water HBs are preferred over surface-water HBs. Such solvent reorganization forces presumably underlie also other important phenomena, such as selective ion adsorption to interfaces as well as ion pair formation.

  4. Strong covalent hydration of terephthalaldehyde.

    PubMed

    Baymak, Melek S; Vercoe, Kellie L; Zuman, Petr

    2005-11-24

    Spectrophotometric and electroanalytical studies indicate that one of the formyl groups of terephthalaldehyde in aqueous solution is present in about 23% as a geminal diol. Stronger covalent hydration of CHO in terephthalaldehyde than in p-nitrobenzaldehyde is attributed to a strong resonance interaction between the two formyl groups.

  5. Hydration rind dates rhyolite flows.

    PubMed

    Friedman, I

    1968-02-23

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.

  6. Hydration rind dates rhyolite flows

    USGS Publications Warehouse

    Friedman, I.

    1968-01-01

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.

  7. The precipitation of potassium aluminium sulphate from aqueous solution

    NASA Astrophysics Data System (ADS)

    Mullin, J. W.; Žáček, S.

    1981-06-01

    A precipitation study has been made with potassium aluminium sulphate (potash alum) produced by mixing aqueous solutions of its constituent salts. Rates of nucleation, as indicated by the induction period, were measured for both agitated and non-agitated solutions over the temperature range 15-35°C. Nucleation rates increase with increases in agitation, temperature and supersaturation, but the latter has the dominant effect, as predicted by classical nucleation theory. The temperature-dependence of the interfacial tension is evaluated.

  8. Dysprozium-activated calcium sulphate in gamma dosimetry

    NASA Astrophysics Data System (ADS)

    Majchrowski, Andrzej; Korman, A.; Zmija, Jozef; Borys, Wieslaw; Malecki, M.; Warkocki, Stanislaw

    1995-10-01

    Results of preliminary investigations of thermoluminescent response of CaSO4Dy to ionizing radiation are reported. Very high sensitivity and good linearity of this luminofor are confirmed in the case of gamma irradiation. Neutron sensitivity of calcium sulphate due to internal conversion of 32S to 32P by fast neutrons was investigated as well, but it does not seem to be sensitive enough to be used in personal dosimetry.

  9. Thermal properties of methane gas hydrates

    USGS Publications Warehouse

    Waite, William F.

    2007-01-01

    Gas hydrates are crystalline solids in which molecules of a “guest” species occupy and stabilize cages formed by water molecules. Similar to ice in appearance (fig. 1), gas hydrates are stable at high pressures and temperatures above freezing (0°C). Methane is the most common naturally occurring hydrate guest species. Methane hydrates, also called simply “gas hydrates,” are extremely concentrated stores of methane and are found in shallow permafrost and continental margin sediments worldwide. Brought to sea-level conditions, methane hydrate breaks down and releases up to 160 times its own volume in methane gas. The methane stored in gas hydrates is of interest and concern to policy makers as a potential alternative energy resource and as a potent greenhouse gas that could be released from sediments to the atmosphere and ocean during global warming. In continental margin settings, methane release from gas hydrates also is a potential geohazard and could cause submarine landslides that endanger offshore infrastructure. Gas hydrate stability is sensitive to temperature changes. To understand methane release from gas hydrate, the U.S. Geological Survey (USGS) conducted a laboratory investigation of pure methane hydrate thermal properties at conditions relevant to accumulations of naturally occurring methane hydrate. Prior to this work, thermal properties for gas hydrates generally were measured on analog systems such as ice and non-methane hydrates or at temperatures below freezing; these conditions limit direct comparisons to methane hydrates in marine and permafrost sediment. Three thermal properties, defined succinctly by Briaud and Chaouch (1997), are estimated from the experiments described here: - Thermal conductivity, λ: if λ is high, heat travels easily through the material. - Thermal diffusivity, κ: if κ is high, it takes little time for the temperature to rise in the material. - Specific heat, cp: if cp is high, it takes a great deal of heat to

  10. [Environmental hygiene and comprehensive processing of copper sulphate ore].

    PubMed

    Petrov, B A

    2004-01-01

    The modern comprehensive processing of copper-sulphate ores is based on using the fire, chemical and combined fire-and-hydrometallurgy processes. The existing schemes of comprehensive ore processing do not provide for a total utilization of the metallurgical cycles wastes due to the inherent technological and design shortcomings; besides, they are a source of environmental pollution. Contamination of the atmospheric air with discharge elements has unfavorable effects on the health condition of population; it worsens the natural body resistance and contributes (through the induction of chromosome aberrations) to a higher general morbidity and mortality due to malignant neoplasms. Health-improve measures are supported by modern achievements in the sphere of copper-sulphate ore processing technologies--they ensure the hygienic and ecological rational management and usage at all stages of the processing of raw materials and secondary products. Institutions of the territorial medical-and-ecological monitoring are the corner stones for ecological safety of persons residing in areas of comprehensive copper-and-sulphate ore processing.

  11. Physicochemical properties, cytotoxicity, and antimicrobial activity of sulphated zirconia nanoparticles

    PubMed Central

    Mftah, Ae; Alhassan, Fatah H; Al-Qubaisi, Mothanna Sadiq; El Zowalaty, Mohamed Ezzat; Webster, Thomas J; Sh-eldin, Mohammed; Rasedee, Abdullah; Taufiq-Yap, Yun Hin; Rashid, Shah Samiur

    2015-01-01

    Nanoparticle sulphated zirconia with Brønsted acidic sites were prepared here by an impregnation reaction followed by calcination at 600°C for 3 hours. The characterization was completed using X-ray diffraction, thermal gravimetric analysis, Fourier transform infrared spectroscopy, Brunner-Emmett-Teller surface area measurements, scanning electron microscopy with energy dispersive X-ray spectroscopy, and transmission electron microscopy. Moreover, the anticancer and antimicrobial effects were investigated for the first time. This study showed for the first time that the exposure of cancer cells to sulphated zirconia nanoparticles (3.9–1,000 μg/mL for 24 hours) resulted in a dose-dependent inhibition of cell growth, as determined by (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Similar promising results were observed for reducing bacteria functions. In this manner, this study demonstrated that sulphated zirconia nanoparticles with Brønsted acidic sites should be further studied for a wide range of anticancer and antibacterial applications. PMID:25632233

  12. Mesoscale texture of cement hydrates.

    PubMed

    Ioannidou, Katerina; Krakowiak, Konrad J; Bauchy, Mathieu; Hoover, Christian G; Masoero, Enrico; Yip, Sidney; Ulm, Franz-Josef; Levitz, Pierre; Pellenq, Roland J-M; Del Gado, Emanuela

    2016-02-23

    Strength and other mechanical properties of cement and concrete rely upon the formation of calcium-silicate-hydrates (C-S-H) during cement hydration. Controlling structure and properties of the C-S-H phase is a challenge, due to the complexity of this hydration product and of the mechanisms that drive its precipitation from the ionic solution upon dissolution of cement grains in water. Departing from traditional models mostly focused on length scales above the micrometer, recent research addressed the molecular structure of C-S-H. However, small-angle neutron scattering, electron-microscopy imaging, and nanoindentation experiments suggest that its mesoscale organization, extending over hundreds of nanometers, may be more important. Here we unveil the C-S-H mesoscale texture, a crucial step to connect the fundamental scales to the macroscale of engineering properties. We use simulations that combine information of the nanoscale building units of C-S-H and their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles. We compute small-angle scattering intensities, pore size distributions, specific surface area, local densities, indentation modulus, and hardness of the material, providing quantitative understanding of different experimental investigations. Our results provide insight into how the heterogeneities developed during the early stages of hydration persist in the structure of C-S-H and impact the mechanical performance of the hardened cement paste. Unraveling such links in cement hydrates can be groundbreaking and controlling them can be the key to smarter mix designs of cementitious materials. PMID:26858450

  13. Physical activity, hydration and health.

    PubMed

    Marcos, Ascensión; Manonelles, Pedro; Palacios, Nieves; Wärnberg, Julia; Casajús, José A; Pérez, Margarita; Aznar, Susana; Benito, Pedro J; Martínez-Gomez, David; Ortega, Francisco B; Ortega, Eduardo; Urrialde, Rafael

    2014-06-01

    Since the beginning of mankind, man has sought ways to promote and preserve health as well as to prevent disease. Hydration, physical activity and exercise are key factors for enhancing human health. However, either a little dose of them or an excess can be harmful for health maintenance at any age. Water is an essential nutrient for human body and a major key to survival has been to prevent dehydration. However, there is still a general controversy regarding the necessary amount to drink water or other beverages to properly get an adequate level of hydration. In addition, up to now the tools used to measure hydration are controversial. To this end, there are several important groups of variables to take into account such as water balance, hydration biomarkers and total body water. A combination of methods will be the most preferred tool to find out any risk or situation of dehydration at any age range. On the other hand, physical activity and exercise are being demonstrated to promote health, avoiding or reducing health problems, vascular and inflammatory disea ses and helping weight management. Therefore, physical activity is also being used as a pill within a therapy to promote health and reduce risk diseases, but as in the case of drugs, dose, intensity, frequency, duration and precautions have to be evaluated and taken into account in order to get the maximum effectiveness and success of a treatment. On the other hand, sedentariness is the opposite concept to physical activity that has been recently recognized as an important factor of lifestyle involved in the obesogenic environment and consequently in the risk of the non-communicable diseases. In view of the literature consulted and taking into account the expertise of the authors, in this review a Decalogue of global recommendations is included to achieve an adequate hydration and physical activity status to avoid overweight/obesity consequences.

  14. Mesoscale texture of cement hydrates

    PubMed Central

    Ioannidou, Katerina; Krakowiak, Konrad J.; Bauchy, Mathieu; Hoover, Christian G.; Masoero, Enrico; Yip, Sidney; Ulm, Franz-Josef; Levitz, Pierre; Pellenq, Roland J.-M.; Del Gado, Emanuela

    2016-01-01

    Strength and other mechanical properties of cement and concrete rely upon the formation of calcium–silicate–hydrates (C–S–H) during cement hydration. Controlling structure and properties of the C–S–H phase is a challenge, due to the complexity of this hydration product and of the mechanisms that drive its precipitation from the ionic solution upon dissolution of cement grains in water. Departing from traditional models mostly focused on length scales above the micrometer, recent research addressed the molecular structure of C–S–H. However, small-angle neutron scattering, electron-microscopy imaging, and nanoindentation experiments suggest that its mesoscale organization, extending over hundreds of nanometers, may be more important. Here we unveil the C–S–H mesoscale texture, a crucial step to connect the fundamental scales to the macroscale of engineering properties. We use simulations that combine information of the nanoscale building units of C–S–H and their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles. We compute small-angle scattering intensities, pore size distributions, specific surface area, local densities, indentation modulus, and hardness of the material, providing quantitative understanding of different experimental investigations. Our results provide insight into how the heterogeneities developed during the early stages of hydration persist in the structure of C–S–H and impact the mechanical performance of the hardened cement paste. Unraveling such links in cement hydrates can be groundbreaking and controlling them can be the key to smarter mix designs of cementitious materials. PMID:26858450

  15. Physical activity, hydration and health.

    PubMed

    Marcos, Ascensión; Manonelles, Pedro; Palacios, Nieves; Wärnberg, Julia; Casajús, José A; Pérez, Margarita; Aznar, Susana; Benito, Pedro J; Martínez-Gomez, David; Ortega, Francisco B; Ortega, Eduardo; Urrialde, Rafael

    2014-01-01

    Since the beginning of mankind, man has sought ways to promote and preserve health as well as to prevent disease. Hydration, physical activity and exercise are key factors for enhancing human health. However, either a little dose of them or an excess can be harmful for health maintenance at any age. Water is an essential nutrient for human body and a major key to survival has been to prevent dehydration. However, there is still a general controversy regarding the necessary amount to drink water or other beverages to properly get an adequate level of hydration. In addition, up to now the tools used to measure hydration are controversial. To this end, there are several important groups of variables to take into account such as water balance, hydration biomarkers and total body water. A combination of methods will be the most preferred tool to find out any risk or situation of dehydration at any age range. On the other hand, physical activity and exercise are being demonstrated to promote health, avoiding or reducing health problems, vascular and inflammatory disea ses and helping weight management. Therefore, physical activity is also being used as a pill within a therapy to promote health and reduce risk diseases, but as in the case of drugs, dose, intensity, frequency, duration and precautions have to be evaluated and taken into account in order to get the maximum effectiveness and success of a treatment. On the other hand, sedentariness is the opposite concept to physical activity that has been recently recognized as an important factor of lifestyle involved in the obesogenic environment and consequently in the risk of the non-communicable diseases. In view of the literature consulted and taking into account the expertise of the authors, in this review a Decalogue of global recommendations is included to achieve an adequate hydration and physical activity status to avoid overweight/obesity consequences. PMID:24972459

  16. Gas hydrate reservoir characteristics and economics

    SciTech Connect

    Collett, T.S.; Bird, K.J.; Burruss, R.C.; Lee, Myung W.

    1992-06-01

    The primary objective of the DOE-funded USGS Gas Hydrate Program is to assess the production characteristics and economic potential of gas hydrates in northern Alaska. The objectives of this project for FY-1992 will include the following: (1) Utilize industry seismic data to assess the distribution of gas hydrates within the nearshore Alaskan continental shelf between Harrison Bay and Prudhoe Bay; (2) Further characterize and quantify the well-log characteristics of gas hydrates; and (3) Establish gas monitoring stations over the Eileen fault zone in northern Alaska, which will be used to measure gas flux from destabilized hydrates.

  17. Gas hydrate reservoir characteristics and economics

    SciTech Connect

    Collett, T.S.; Bird, K.J.; Burruss, R.C.; Lee, Myung W.

    1992-01-01

    The primary objective of the DOE-funded USGS Gas Hydrate Program is to assess the production characteristics and economic potential of gas hydrates in northern Alaska. The objectives of this project for FY-1992 will include the following: (1) Utilize industry seismic data to assess the distribution of gas hydrates within the nearshore Alaskan continental shelf between Harrison Bay and Prudhoe Bay; (2) Further characterize and quantify the well-log characteristics of gas hydrates; and (3) Establish gas monitoring stations over the Eileen fault zone in northern Alaska, which will be used to measure gas flux from destabilized hydrates.

  18. Chemical stabilities of isoetharine hydrochloride, metaproterenol sulphate and terbutaline sulphate after mixing with normal saline for respiratory therapy.

    PubMed

    Das Gupta, V; Parasrampuria, J; Gardner, S N

    1988-04-01

    The chemical stabilities of isoetharine hydrochloride inhalation solution, metaproterenol sulphate inhalation solution and terbutaline sulphate injection, after diluting 1 in 10 with sodium chloride 0.9% injection were studied. On storing the solutions in amber-coloured syringes, they were stable for at least 120 days at 5 degrees C. At 25 degrees C they were also stable for 120 days except that isoetharine solution discoloured and lost 7.8% of its potency after 90 days of storage. There was a new peak in the chromatogram from the decomposition product. All other solutions remained clear for 120 days at both temperatures. The initial and final pH values were similar except that after 120 days at both temperatures. The initial and final pH values were similar except that after 120 days at 25 degrees C, the pH value of terbutaline solution had increased from 4.9 to 5.4. PMID:3392129

  19. Well log evaluation of gas hydrate saturations

    USGS Publications Warehouse

    Collett, T.S.

    1998-01-01

    The amount of gas sequestered in gas hydrates is probably enormous, but estimates are highly speculative due to the lack of previous quantitative studies. Gas volumes that may be attributed to a gas hydrate accumulation within a given geologic setting are dependent on a number of reservoir parameters; one of which, gas-hydrate saturation, can be assessed with data obtained from downhole well logging devices. The primary objective of this study was to develop quantitative well-log evaluation techniques which will permit the calculation of gas-hydrate saturations in gas-hydrate-bearing sedimentary units. The "standard" and "quick look" Archie relations (resistivity log data) yielded accurate gas-hydrate and free-gas saturations within all of the gas hydrate accumulations assessed in the field verification phase of the study. Compressional wave acoustic log data have been used along with the Timur, modified Wood, and the Lee weighted average acoustic equations to calculate accurate gas-hydrate saturations in all of the gas hydrate accumulations assessed in this study. The well log derived gas-hydrate saturations calculated in the field verification phase of this study, which range from as low as 2% to as high as 97%, confirm that gas hydrates represent a potentially important source of natural gas.

  20. Handbook of gas hydrate properties and occurrence

    SciTech Connect

    Kuustraa, V.A.; Hammershaimb, E.C.

    1983-12-01

    This handbook provides data on the resource potential of naturally occurring hydrates, the properties that are needed to evaluate their recovery, and their production potential. The first two chapters give data on the naturally occurring hydrate potential by reviewing published resource estimates and the known and inferred occurrences. The third and fourth chapters review the physical and thermodynamic properties of hydrates, respectively. The thermodynamic properties of hydrates that are discussed include dissociation energies and a simplified method to calculate them; phase diagrams for simple and multi-component gases; the thermal conductivity; and the kinetics of hydrate dissociation. The final chapter evaluates the net energy balance of recovering hydrates and shows that a substantial positive energy balance can theoretically be achieved. The Appendices of the Handbook summarize physical and thermodynamic properties of gases, liquids and solids that can be used in designing and evaluating recovery processes of hydrates. 158 references, 67 figures, 47 tables.

  1. Chemical sulphate removal for treatment of construction and demolition debris leachate.

    PubMed

    Kijjanapanich, Pimluck; Annachhatre, Ajit P; Esposito, Giovanni; Lens, Piet N L

    2014-08-01

    Construction and demolition debris (CDD) is a product of construction, renovation or demolition activities. It has a high gypsum content (52.4% of total gypsum), concentrated in the CDD sand (CDDS) fraction. To comply with the posed limit of the maximum amount of sulphate present in building sand, excess sulphate needs to be removed. In order to enable reuse of CDDS, a novel treatment process is developed based on washing of the CDDS to remove most of the gypsum, and subsequent sulphate removal from the sulphate-rich CDDS leachate. This study aims to assess chemical techniques, i.e. precipitation and adsorption, for sulphate removal from the CDDS leachate. Good sulphate removal efficiencies (up to 99.9%) from the CDDS leachate can be achieved by precipitation with barium chloride (BaCl2) and lead(II) nitrate (Pb(NO3)2). Precipitation with calcium chloride (CaCl2), calcium carbonate (CaCO3) and calcium oxide (CaO) gave less efficient sulphate removal. Adsorption of sulphate to aluminium oxide (Al2O3) yielded a 50% sulphate removal efficiency, whereas iron oxide-coated sand as adsorbent gave only poor (10%) sulphate removal efficiencies.

  2. BARIUM SULPHATE ABSORPTION AND THE SERUM DIAGNOSIS OF SYPHILIS.

    PubMed

    Noguchi, H; Bronfenbrenner, J

    1911-02-01

    The so-called syphilitic antibodies can be removed from a serum by means of absorption with barium sulphate. The removal is due either to an adsorption or a mechanical absorption. The activity of the syphilitic antibodies is thereby unimpaired. The readiness with which the absorption is accomplished with barium sulphate varies considerably with different syphilitic sera. That barium sulphate exerts the same absorbing effect upon non-syphilitic serum components is made evident by the interfering property which the latter manifest in the absorption experiment of the syphilitic antibodies. The selective removal of the serum components, other than the syphilitic antibodies, by means of barium sulphate absorption is, therefore, impossible. On the other hand, a partial removal of these components, with but little removal of the syphilitic antibodies, may be effected when the content of a given serum is poor in syphilitic antibodies and comparatively rich in the indifferent serum components. But this is impossible if the conditions are reversed. The main reasons why some negative syphilitic sera may be so modified by the barium sulphate treatment as to give positive reactions, are explained below, but these apply only to those methods in which inactivated serum is employed. The inactivation reduces the antibody content to about one-fourth to one-fifth of the original. When the serum is very rich in antibodies, this does not affect the result of the fixation test. But when the amount of the antibodies is small, the process of inactivation creates conditions quite unexpected. It may produce such a condition that a given amount of the serum contains, after inactivation, only one or two antibody units, while the other serum components remain undiminished. Here one must not lose sight of the vital fact that these apparently indifferent serum constituents are not at all indifferent in the fixation processes. They may possess affinities which are similar to those of complement

  3. Sulphate aerosol size distributions at Mumbai, India, during the INDOEX-FFP (1998)

    NASA Astrophysics Data System (ADS)

    Venkataraman, Chandra; Sinha, Prashant; Bammi, Sachin

    Sulphate size distributions were measured at the coastal station of Mumbai (formerly Bombay) through 1998, during the Indian ocean experiment (INDOEX) first field phase (FFP), to fill current gaps in size-resolved aerosol chemical composition data. The paper examines meteorological, seasonal and source-contribution effects on sulphate aerosol and discusses potential effects of sulphate on regional climate. Sulphate size-distributions were largely trimodal with a condensation mode (mass median aerodynamic diameter or MMAD 0.6 μm), a droplet mode (MMAD 1.9-2.4 μm) and a coarse mode (MMAD 5 μm). Condensation mode sulphate mass-fractions were highest in winter, consistent with the high meteorological potential for gas-to-particle conversion along with low relative humidity (RH). The droplet mode concentrations and MMADs were larger in the pre-monsoon and winter than in monsoon, implying sulphate predominance in larger sized particles within this mode. In these seasons the high RH, and consequently greater aerosol water in the droplet mode, would favour aerosol-phase partitioning and reactions of SO 2. Coarse mode sulphate concentrations were lowest in the monsoon, when continental contribution to sulphate was low and washout was efficient. In winter and pre-monsoon, coarse mode sulphate concentrations were somewhat higher, likely from SO 2 gas-to-particle conversion. Low daytime sulphate concentrations with a large coarse fraction, along with largely onshore winds, indicated marine aerosol predominance. High nighttime sulphate concentrations and a coincident large fine fraction indicated contributions from anthropogenic/industrial sources or from gas-to-particle conversion. Monthly mean sulphate concentrations increased with increasing SO 2 concentrations, RH and easterly wind direction, indicating the importance of gas-to-particle conversion and industrial sources located to the east. Atmospheric chemistry effects on sulphate size distributions in Mumbai, indicated

  4. Thermal conductivity of hydrate-bearing sediments

    USGS Publications Warehouse

    Cortes, D.D.; Martin, A.I.; Yun, T.S.; Francisca, F.M.; Santamarina, J.C.; Ruppel, C.

    2009-01-01

    A thorough understanding of the thermal conductivity of hydrate-bearing sediments is necessary for evaluating phase transformation processes that would accompany energy production from gas hydrate deposits and for estimating regional heat flow based on the observed depth to the base of the gas hydrate stability zone. The coexistence of multiple phases (gas hydrate, liquid and gas pore fill, and solid sediment grains) and their complex spatial arrangement hinder the a priori prediction of the thermal conductivity of hydrate-bearing sediments. Previous studies have been unable to capture the full parameter space covered by variations in grain size, specific surface, degree of saturation, nature of pore filling material, and effective stress for hydrate-bearing samples. Here we report on systematic measurements of the thermal conductivity of air dry, water- and tetrohydrofuran (THF)-saturated, and THF hydrate-saturated sand and clay samples at vertical effective stress of 0.05 to 1 MPa (corresponding to depths as great as 100 m below seafloor). Results reveal that the bulk thermal conductivity of the samples in every case reflects a complex interplay among particle size, effective stress, porosity, and fluid-versus-hydrate filled pore spaces. The thermal conductivity of THF hydrate-bearing soils increases upon hydrate formation although the thermal conductivities of THF solution and THF hydrate are almost the same. Several mechanisms can contribute to this effect including cryogenic suction during hydrate crystal growth and the ensuing porosity reduction in the surrounding sediment, increased mean effective stress due to hydrate formation under zero lateral strain conditions, and decreased interface thermal impedance as grain-liquid interfaces are transformed into grain-hydrate interfaces. Copyright 2009 by the American Geophysical Union.

  5. Well log characterization of natural gas hydrates

    USGS Publications Warehouse

    Collett, Timothy S.; Lee, Myung W.

    2011-01-01

    In the last 25 years we have seen significant advancements in the use of downhole well logging tools to acquire detailed information on the occurrence of gas hydrate in nature: From an early start of using wireline electrical resistivity and acoustic logs to identify gas hydrate occurrences in wells drilled in Arctic permafrost environments to today where wireline and advanced logging-while-drilling tools are routinely used to examine the petrophysical nature of gas hydrate reservoirs and the distribution and concentration of gas hydrates within various complex reservoir systems. The most established and well known use of downhole log data in gas hydrate research is the use of electrical resistivity and acoustic velocity data (both compressional- and shear-wave data) to make estimates of gas hydrate content (i.e., reservoir saturations) in various sediment types and geologic settings. New downhole logging tools designed to make directionally oriented acoustic and propagation resistivity log measurements have provided the data needed to analyze the acoustic and electrical anisotropic properties of both highly inter-bedded and fracture dominated gas hydrate reservoirs. Advancements in nuclear-magnetic-resonance (NMR) logging and wireline formation testing have also allowed for the characterization of gas hydrate at the pore scale. Integrated NMR and formation testing studies from northern Canada and Alaska have yielded valuable insight into how gas hydrates are physically distributed in sediments and the occurrence and nature of pore fluids (i.e., free-water along with clay and capillary bound water) in gas-hydrate-bearing reservoirs. Information on the distribution of gas hydrate at the pore scale has provided invaluable insight on the mechanisms controlling the formation and occurrence of gas hydrate in nature along with data on gas hydrate reservoir properties (i.e., permeabilities) needed to accurately predict gas production rates for various gas hydrate

  6. The effect of hydrate saturation on water retention curves in hydrate-bearing sediments

    NASA Astrophysics Data System (ADS)

    Mahabadi, Nariman; Zheng, Xianglei; Jang, Jaewon

    2016-05-01

    The experimental measurement of water retention curve in hydrate-bearing sediments is critically important to understand the behavior of hydrate dissociation and gas production. In this study, tetrahydrofuran (THF) is selected as hydrate former. The pore habit of THF hydrates is investigated by visual observation in a transparent micromodel. It is confirmed that THF hydrates are not wetting phase on the quartz surface of the micromodel and occupy either an entire pore or part of pore space resulting in change in pore size distribution. And the measurement of water retention curves in THF hydrate-bearing sediments with hydrate saturation ranging from Sh = 0 to Sh = 0.7 is conducted for excess water condition. The experimental results show that the gas entry pressure and the capillary pressure increase with increasing hydrate saturation. Based on the experimental results, fitting parameters for van Genuchten equation are suggested for different hydrate saturation conditions.

  7. Improved Design and Fabrication of Hydrated-Salt Pills

    NASA Technical Reports Server (NTRS)

    Shirron, Peter J.; DiPirro, Michael J.; Canavan, Edgar R.

    2011-01-01

    A high-performance design, and fabrication and growth processes to implement the design, have been devised for encapsulating a hydrated salt in a container that both protects the salt and provides thermal conductance between the salt and the environment surrounding the container. The unitary salt/container structure is known in the art as a salt pill. In the original application of the present design and processes, the salt is, more specifically, a hydrated paramagnetic salt, for use as a refrigerant in a very-low-temperature adiabatic demagnetization refrigerator (ADR). The design and process can also be applied, with modifications, to other hydrated salts. Hydrated paramagnetic salts have long been used in ADRs because they have the desired magnetic properties at low temperatures. They also have some properties, disadvantageous for ADRs, that dictate the kind of enclosures in which they must be housed: Being hydrated, they lose water if exposed to less than 100-percent relative humidity. Because any dehydration compromises their magnetic properties, salts used in ADRs must be sealed in hermetic containers. Because they have relatively poor thermal conductivities in the temperature range of interest (<0.1 K), integral thermal buses are needed as means of efficiently transferring heat to and from the salts during refrigeration cycles. A thermal bus is typically made from a high-thermal-conductivity met al (such as copper or gold), and the salt is configured to make intimate thermal contact with the metal. Commonly in current practice (and in the present design), the thermal bus includes a matrix of wires or rods, and the salt is grown onto this matrix. The density and spacing of the conductors depend on the heat fluxes that must be accommodated during operation.

  8. Preface to the special issue on gas hydrate drilling in the Eastern Nankai Trough

    USGS Publications Warehouse

    Yamamoto, Koji; Ruppel, Carolyn

    2015-01-01

    Methane hydrate traps enormous amounts of methane in frozen deposits in continental margin sediments, and these deposits have long been targeted for studies investigating their potential as an energy resource. As a concentrated form of methane that occurs at shallower depths than conventional and most unconventional gas reservoirs, methane hydrates could be a readily accessible source of hydrocarbons for countries hosting deposits within their Exclusive Economic Zones. Japan is one such country, and since 2001 the Research Consortium for Methane Hydrate Resources in Japan (referred to as MH21) has conducted laboratory, modeling, and field-based programs to study methane hydrates as an energy resource. The MH21 consortium is funded by the Japanese Ministry of Trade and Industry (METI) and led by the Japan Oil, Gas and Metals National Oil Corporation (JOGMEC) and the National Institute of Advanced Industrial Science and Technology (AIST).

  9. Formation of magnesium silicate hydrate (M-S-H) cement pastes using sodium hexametaphosphate

    SciTech Connect

    Zhang, Tingting; Vandeperre, Luc J.; Cheeseman, Christopher R.

    2014-11-15

    Magnesium silicate hydrate (M-S-H) gel is formed by the reaction of brucite with amorphous silica during sulphate attack in concrete and M-S-H is therefore regarded as having limited cementing properties. The aim of this work was to form M-S-H pastes, characterise the hydration reactions and assess the resulting properties. It is shown that M-S-H pastes can be prepared by reacting magnesium oxide (MgO) and silica fume (SF) at low water to solid ratio using sodium hexametaphosphate (NaHMP) as a dispersant. Characterisation of the hydration reactions by x-ray diffraction and thermogravimetric analysis shows that brucite and M-S-H gel are formed and that for samples containing 60 wt.% SF and 40 wt.% MgO all of the brucites react with SF to form M-S-H gel. These M-S-H cement pastes were found to have compressive strengths in excess of 70 MPa.

  10. Imaging hydrated microbial extracellular polymers: Comparative analysis by electron microscopy

    SciTech Connect

    Dohnalkova, A.C.; Marshall, M. J.; Arey, B. W.; Williams, K. H.; Buck, E. C.; Fredrickson, J. K.

    2011-01-01

    Microbe-mineral and -metal interactions represent a major intersection between the biosphere and geosphere but require high-resolution imaging and analytical tools for investigating microscale associations. Electron microscopy has been used extensively for geomicrobial investigations and although used bona fide, the traditional methods of sample preparation do not preserve the native morphology of microbiological components, especially extracellular polymers. Herein, we present a direct comparative analysis of microbial interactions using conventional electron microscopy approaches of imaging at room temperature and a suite of cryogenic electron microscopy methods providing imaging in the close-to-natural hydrated state. In situ, we observed an irreversible transformation of the hydrated bacterial extracellular polymers during the traditional dehydration-based sample preparation that resulted in their collapse into filamentous structures. Dehydration-induced polymer collapse can lead to inaccurate spatial relationships and hence could subsequently affect conclusions regarding nature of interactions between microbial extracellular polymers and their environment.

  11. Imaging Hydrated Microbial Extracellular Polymers: Comparative Analysis by Electron Microscopy

    SciTech Connect

    Dohnalkova, Alice; Marshall, Matthew J.; Arey, Bruce W.; Williams, Kenneth H.; Buck, Edgar C.; Fredrickson, Jim K.

    2011-02-01

    Microbe-mineral and -metal interactions represent a major intersection between the biosphere and geosphere but require high-resolution imaging and analytical tools for investigating microscale associations. Electron microscopy has been used extensively for geomicrobial investigations and although used bona fide, the traditional methods of sample preparation do not preserve the native morphology of microbiological components, especially extracellular polymers. Herein, we present a direct comparative analysis of microbial interactions using conventional electron microscopy approaches of imaging at room temperature and a suite of cryo-electron microscopy methods providing imaging in the close-to-natural hydrated state. In situ, we observed an irreversible transformation of bacterial extracellular polymers during the traditional dehydration-based sample preparation that resulted in the collapse of hydrated gel-like EPS into filamentous structures. Dehydration-induced polymer collapse can lead to inaccurate spatial relationships and hence could subsequently affect conclusions regarding nature of interactions between microbial extracellular polymers and their environment.

  12. Gas hydrate cool storage system

    DOEpatents

    Ternes, Mark P.; Kedl, Robert J.

    1985-01-01

    This invention is a process for formation of a gas hydrate to be used as a cool storage medium using a refrigerant in water. Mixing of the immiscible refrigerant and water is effected by addition of a surfactant and agitation. The difficult problem of subcooling during the process is overcome by using the surfactant and agitation and performance of the process significantly improves and approaches ideal.

  13. Gas hydrate resources of northern Alaska

    USGS Publications Warehouse

    Collett, T.S.

    1997-01-01

    Large amounts of natural gas, composed mainly of methane, can occur in arctic sedimentary basins in the form of gas hydrates under appropriate temperature and pressure conditions. Gas hydrates are solids, composed of rigid cages of water molecules that trap molecules of gas. These substances are regarded as a potential unconventional source of natural gas because of their enormous gas-storage capacity. Most published gas hydrate resource estimates are highly simplified and based on limited geological data. The gas hydrate resource assessment for northern Alaska presented in this paper is based on a "play analysis" scheme, in which geological factors controlling the accumulation and preservation of gas hydrates are individually evaluated and risked for each hydrate play. This resource assessment identified two gas hydrate plays; the in-place gas resources within the gas hydrates of northern Alaska are estimated to range from 6.7 to 66.8 trillion cubic metres of gas (236 to 2,357 trillion cubic feet of gas), at the 0.50 and 0.05 probability levels respectively. The mean in-place hydrate resource estimate for northern Alaska is calculated to be 16.7 trillion cubic metres of gas (590 trillion cubic feet of gas). If this assessment is valid, the amount of natural gas stored as gas hydrates in northern Alaska could be almost seven times larger then the estimated total remaining recoverable conventional natural gas resources in the entire United States.

  14. Well log evaluation of gas hydrate saturations

    USGS Publications Warehouse

    Collett, Timothy S.

    1998-01-01

    The amount of gas sequestered in gas hydrates is probably enormous, but estimates are highly speculative due to the lack of previous quantitative studies. Gas volumes that may be attributed to a gas hydrate accumulation within a given geologic setting are dependent on a number of reservoir parameters; one of which, gas-hydrate saturation, can be assessed with data obtained from downhole well logging devices. The primary objective of this study was to develop quantitative well-log evaluation techniques which will permit the calculation of gas-hydrate saturations in gas-hydrate-bearing sedimentary units. The `standard' and `quick look' Archie relations (resistivity log data) yielded accurate gas-hydrate and free-gas saturations within all of the gas hydrate accumulations assessed in the field verification phase of the study. Compressional wave acoustic log data have been used along with the Timur, modified Wood, and the Lee weighted average acoustic equations to calculate accurate gas-hydrate saturations in this study. The well log derived gas-hydrate saturations calculated in the field verification phase of this study, which range from as low as 2% to as high as 97%, confirm that gas hydrates represent a potentially important source of natural gas.

  15. Gas hydrates: Technology status report

    SciTech Connect

    Not Available

    1987-01-01

    In 1983, the US Department of Energy (DOE) assumed the responsibility for expanding the knowledge base and for developing methods to recover gas from hydrates. These are ice-like mixtures of gas and water where gas molecules are trapped within a framework of water molecules. This research is part of the Unconventional Gas Recovery (UGR) program, a multidisciplinary effort that focuses on developing the technology to produce natural gas from resources that have been classified as unconventional because of their unique geologies and production mechanisms. Current work on gas hydrates emphasizes geological studies; characterization of the resource; and generic research, including modeling of reservoir conditions, production concepts, and predictive strategies for stimulated wells. Complementing this work is research on in situ detection of hydrates and field tests to verify extraction methods. Thus, current research will provide a comprehensive technology base from which estimates of reserve potential can be made, and from which industry can develop recovery strategies. 7 refs., 3 figs., 6 tabs.

  16. Energy landscape of clathrate hydrates

    NASA Astrophysics Data System (ADS)

    Desmedt, A.; Bedouret, L.; Pefoute, E.; Pouvreau, M.; Say-Liang-Fat, S.; Alvarez, M.

    2012-11-01

    Clathrate hydrates are nanoporous crystalline materials made of a network of hydrogen-bonded water molecules (forming host cages) that is stabilized by the presence of foreign (generally hydrophobic) guest molecules. The natural existence of large quantities of hydrocarbon hydrates in deep oceans and permafrost is certainly at the origin of numerous applications in the broad areas of energy and environmental sciences and technologies (e.g. gas storage). At a fundamental level, their nanostructuration confers on these materials specific properties (e.g. their "glass-like" thermal conductivity) for which the host-guest interactions play a key role. These interactions occur on broad timescale and thus require the use of multi-technique approach in which neutron scattering brings unvaluable information. This work reviews the dynamical properties of clathrate hydrates, ranging from intramolecular vibrations to Brownian relaxations; it illustrates the contribution of neutron scattering in the understanding of the underlying factors governing chemical-physics properties specific to these nanoporous systems.

  17. Unintended consequences of atmospheric injection of sulphate aerosols.

    SciTech Connect

    Brady, Patrick Vane; Kobos, Peter Holmes; Goldstein, Barry

    2010-10-01

    Most climate scientists believe that climate geoengineering is best considered as a potential complement to the mitigation of CO{sub 2} emissions, rather than as an alternative to it. Strong mitigation could achieve the equivalent of up to -4Wm{sup -2} radiative forcing on the century timescale, relative to a worst case scenario for rising CO{sub 2}. However, to tackle the remaining 3Wm{sup -2}, which are likely even in a best case scenario of strongly mitigated CO{sub 2} releases, a number of geoengineering options show promise. Injecting stratospheric aerosols is one of the least expensive and, potentially, most effective approaches and for that reason an examination of the possible unintended consequences of the implementation of atmospheric injections of sulphate aerosols was made. Chief among these are: reductions in rainfall, slowing of atmospheric ozone rebound, and differential changes in weather patterns. At the same time, there will be an increase in plant productivity. Lastly, because atmospheric sulphate injection would not mitigate ocean acidification, another side effect of fossil fuel burning, it would provide only a partial solution. Future research should aim at ameliorating the possible negative unintended consequences of atmospheric injections of sulphate injection. This might include modeling the optimum rate and particle type and size of aerosol injection, as well as the latitudinal, longitudinal and altitude of injection sites, to balance radiative forcing to decrease negative regional impacts. Similarly, future research might include modeling the optimum rate of decrease and location of injection sites to be closed to reduce or slow rapid warming upon aerosol injection cessation. A fruitful area for future research might be system modeling to enhance the possible positive increases in agricultural productivity. All such modeling must be supported by data collection and laboratory and field testing to enable iterative modeling to increase the

  18. Study of Formation Mechanisms of Gas Hydrate

    NASA Astrophysics Data System (ADS)

    Yang, Jia-Sheng; Wu, Cheng-Yueh; Hsieh, Bieng-Zih

    2015-04-01

    Gas hydrates, which had been found in subsurface geological environments of deep-sea sediments and permafrost regions, are solid crystalline compounds of gas molecules and water. The estimated energy resources of hydrates are at least twice of that of the conventional fossil fuel in the world. Gas hydrates have a great opportunity to become a dominating future energy. In the past years, many laboratory experiments had been conducted to study chemical and thermodynamic characteristics of gas hydrates in order to investigate the formation and dissociation mechanisms of hydrates. However, it is difficult to observe the formation and dissociation of hydrates in a porous media from a physical experiment directly. The purpose of this study was to model the dynamic formation mechanisms of gas hydrate in porous media by reservoir simulation. Two models were designed for this study: 1) a closed-system static model with separated gas and water zones; this model was a hydrate equilibrium model to investigate the behavior of the formation of hydrates near the initial gas-water contact; and 2) an open-system dynamic model with a continuous bottom-up gas flow; this model simulated the behavior of gas migration and studied the formation of hydrates from flowed gas and static formation water in porous media. A phase behavior module was developed in this study for reservoir simulator to model the pressure-volume-temperature (PVT) behavior of hydrates. The thermodynamic equilibriums and chemical reactions were coupled with the phase behavior module to have functions modelling the formation and dissociation of hydrates from/to water and gas. The simulation models used in this study were validated from the code-comparison project proposed by the NETL. According to the modelling results of the closed-system static model, we found that predominated location for the formation of hydrates was below the gas-water contact (or at the top of water zone). The maximum hydrate saturation

  19. The petrography, mineralogy and origins of calcium sulphate within the Cold Bokkeveld CM carbonaceous chondrite

    NASA Astrophysics Data System (ADS)

    Lee, M. R.

    1993-03-01

    A detailed scanning and transmission electron microscopy study was carried out on the Cold Bokkeveld chondrite. Fracture-filling calcium sulphate, calcium sulphate within calcitized chondrules and within the matrix calcite was examined. Results indicate that calcium sulphate is widespread and the majority of its crystals are fibrous. The calcium sulphate is composed of a fine-scale structure of hemihydrate and anhydrate which may have been formed by dehydration of primary gypsum during sample preparation. The timing and origin of aqueous solutions and alteration of the chondrite are discussed and possible links with CI meteorites are considered.

  20. Stable isotopic evidence for anaerobic maintained sulphate discharge in a polythermal glacier

    NASA Astrophysics Data System (ADS)

    Ansari, A. H.

    2016-03-01

    To understand the sources and sinks of sulphate and associated biogeochemical processes in a High Arctic environment, late winter snowpacks, the summer melt-waters and rock samples were collected and analysed for major ions and stable isotope tracers (δ18O, δ34S). The SO42bar/Clbar ratio reveal that more than 87% of sulphate (frequently > 95%) of total sulphate carried by the subglacial runoff and proglacial streams was derived from non-snowpack sources. The proximity of non-snowpack sulphate δ34S (∼8-19‰) to the δ34S of the major rocks in the vicinity (∼-6 to +18‰) suggest that the non-snowpack sulphate was principally derived from rock weathering. Furthermore, Ca2++Mg2+/SO42ˉ molar shows that sulphate acquisition in the meltwaters was controlled by two major processes: 1) coupled-sulphide carbonate weathering (molar ratio ∼ 2) and, 2) re-dissolution of secondary salts (molar ratio ∼ 1). The δ34S-SO4 = +19.4‰ > δ34S-S of rock, accompanied by increased sulphate concentration also indicates an input from re-dissolution of secondary salts. Overall, δ18O composition of these non-snowpack sulphate (-11.9 to -2.2‰) mostly stayed below the threshold δ18O value (-6.7 to -3.3‰) for minimum O2 condition, suggesting that certain proportion of sulphate was regularly supplied from anaerobic sulphide oxidation.

  1. Crystal growth of calcium sulphate dihydrate at low supersaturation

    NASA Astrophysics Data System (ADS)

    Christoffersen, M. R.; Christoffersen, J.; Weijnen, M. P. C.; Van Rosmalen, G. M.

    1982-08-01

    The growth rate of calcium sulphate dihydrate crystals, gypsum, in aqueous suspension has been shown to be screw dislocation controlled in the supersaturation range 1.03< {C}/{C s}<1.15 . Constant composition experiments show that the overall rate of growth decreases with increasing mass of the crystals. A combination of normal spiral growth, growth of cooperating spirals with non-parallel Burgers vectors, and growth of grain boundary spirals, together with partial outgrowth of concave parts of the crystals, can explain the rate of growth found for different preparations of gypsum crytals.

  2. Modelling the growth of triglycine sulphate crystals in Spacelab 3

    NASA Technical Reports Server (NTRS)

    Yoo, Hak-Do; Wilcox, William R.; Lal, Ravindra; Trolinger, James D.

    1988-01-01

    Two triglycine sulphate crystals were grown from an aqueous solution on the Spacelab 3 mission. Using a diffusion coefficient of 0.00002 sq cm/sec, a computer simulation gave reasonable agreement between experimental and theoretical crystal sizes and interferometric lines in the solution near the growing crystal. This diffusion coefficient is larger than most measured values, possibly due to fluctuating accelerations on the order of 0.001 g. The average acceleration was estimated to be less than 10 to the -6th g. At this level buoyancy-driven convection is predicted to add approximately 20 percent to the steady-state growth rate.

  3. 1H-n.m.r. investigation of naturally occurring and chemically oversulphated dermatan sulphates. Identification of minor monosaccharide residues.

    PubMed Central

    Bossennec, V; Petitou, M; Perly, B

    1990-01-01

    The 1H-n.m.r. spectra of various dermatan sulphate preparations present, besides the major signals of the basic disaccharide unit, several other minor signals. We have assigned most of them by n.m.r., using two-dimensional proton-proton double-quantum-correlation and nuclear-Overhauser-effect spectroscopy experiments. This allowed us to identify 2-O-sulphated L-iduronic acid and D-glucuronic acid residues as well as 6-sulphated N-acetylgalactosamine (presumably 4-O-sulphated as well). 2-O-Sulphated iduronic acid was present to similar extents (6-10% of total uronic acids) in pig skin dermatan sulphate and pig intestine dermatan sulphate, whereas glucuronic acid represented 17% of the uronic acid of pig skin dermatan sulphate and was virtually absent (1%) from the other preparation. 6-O-Sulphated N-acetylgalactosamine was present in minor amounts in pig intestine dermatan sulphate only. The influence of sulphation of iduronic acid units on their conformation was assessed by using chemically oversulphated pig intestine dermatan sulphate. Introduction of sulphate groups in this unit in dermatan sulphate tends to shift the conformational equilibrium towards the 1C4 conformer. PMID:2339978

  4. Development of Alaskan gas hydrate resources

    SciTech Connect

    Kamath, V.A.; Sharma, G.D.; Patil, S.L.

    1991-06-01

    The research undertaken in this project pertains to study of various techniques for production of natural gas from Alaskan gas hydrates such as, depressurization, injection of hot water, steam, brine, methanol and ethylene glycol solutions through experimental investigation of decomposition characteristics of hydrate cores. An experimental study has been conducted to measure the effective gas permeability changes as hydrates form in the sandpack and the results have been used to determine the reduction in the effective gas permeability of the sandpack as a function of hydrate saturation. A user friendly, interactive, menu-driven, numerical difference simulator has been developed to model the dissociation of natural gas hydrates in porous media with variable thermal properties. A numerical, finite element simulator has been developed to model the dissociation of hydrates during hot water injection process.

  5. Fundamentals and applications of gas hydrates.

    PubMed

    Koh, Carolyn A; Sloan, E Dendy; Sum, Amadeu K; Wu, David T

    2011-01-01

    Fundamental understanding of gas hydrate formation and decomposition processes is critical in many energy and environmental areas and has special importance in flow assurance for the oil and gas industry. These areas represent the core of gas hydrate applications, which, albeit widely studied, are still developing as growing fields of research. Discovering the molecular pathways and chemical and physical concepts underlying gas hydrate formation potentially can lead us beyond flowline blockage prevention strategies toward advancing new technological solutions for fuel storage and transportation, safely producing a new energy resource from natural deposits of gas hydrates in oceanic and arctic sediments, and potentially facilitating effective desalination of seawater. The state of the art in gas hydrate research is leading us to new understanding of formation and dissociation phenomena that focuses on measurement and modeling of time-dependent properties of gas hydrates on the basis of their well-established thermodynamic properties.

  6. Geomechanical Modeling of Gas Hydrate Bearing Sediments

    NASA Astrophysics Data System (ADS)

    Sanchez, M. J.; Gai, X., Sr.

    2015-12-01

    This contribution focuses on an advance geomechanical model for methane hydrate-bearing soils based on concepts of elasto-plasticity for strain hardening/softening soils and incorporates bonding and damage effects. The core of the proposed model includes: a hierarchical single surface critical state framework, sub-loading concepts for modeling the plastic strains generally observed inside the yield surface and a hydrate enhancement factor to account for the cementing effects provided by the presence of hydrates in sediments. The proposed framework has been validated against recently published experiments involving both, synthetic and natural hydrate soils, as well as different sediments types (i.e., different hydrate saturations, and different hydrates morphologies) and confinement conditions. The performance of the model in these different case studies was very satisfactory.

  7. Fundamentals and applications of gas hydrates.

    PubMed

    Koh, Carolyn A; Sloan, E Dendy; Sum, Amadeu K; Wu, David T

    2011-01-01

    Fundamental understanding of gas hydrate formation and decomposition processes is critical in many energy and environmental areas and has special importance in flow assurance for the oil and gas industry. These areas represent the core of gas hydrate applications, which, albeit widely studied, are still developing as growing fields of research. Discovering the molecular pathways and chemical and physical concepts underlying gas hydrate formation potentially can lead us beyond flowline blockage prevention strategies toward advancing new technological solutions for fuel storage and transportation, safely producing a new energy resource from natural deposits of gas hydrates in oceanic and arctic sediments, and potentially facilitating effective desalination of seawater. The state of the art in gas hydrate research is leading us to new understanding of formation and dissociation phenomena that focuses on measurement and modeling of time-dependent properties of gas hydrates on the basis of their well-established thermodynamic properties. PMID:22432618

  8. Gas hydrates of outer continental margins

    SciTech Connect

    Kvenvolden, K.A. )

    1990-05-01

    Gas hydrates are crystalline substances in which a rigid framework of water molecules traps molecules of gas, mainly methane. Gas-hydrate deposits are common in continental margin sediment in all major oceans at water depths greater than about 300 m. Thirty-three localities with evidence for gas-hydrate occurrence have been described worldwide. The presence of these gas hydrates has been inferred mainly from anomalous lacoustic reflectors seen on marine seismic records. Naturally occurring marine gas hydrates have been sampled and analyzed at about tensites in several regions including continental slope and rise sediment of the eastern Pacific Ocean and the Gulf of Mexico. Except for some Gulf of Mexico gas hydrate occurrences, the analyzed gas hydrates are composed almost exclusively of microbial methane. Evidence for the microbial origin of methane in gas hydrates includes (1) the inverse relation between methane occurence and sulfate concentration in the sediment, (2) the subparallel depth trends in carbon isotopic compositions of methane and bicarbonate in the interstitial water, and (3) the general range of {sup 13}C depletion ({delta}{sub PDB}{sup 13}C = {minus}90 to {minus}60 {per thousand}) in the methane. Analyses of gas hydrates from the Peruvian outer continental margin in particular illustrate this evidence for microbially generated methane. The total amount of methane in gas hydrates of continental margins is not known, but estimates of about 10{sup 16} m{sup 3} seem reasonable. Although this amount of methane is large, it is not yet clear whether methane hydrates of outer continental margins will ever be a significant energy resource; however, these gas hydrates will probably constitute a drilling hazard when outer continental margins are explored in the future.

  9. Natural gas hydrate occurrence and issues

    USGS Publications Warehouse

    Kvenvolden, K.A.

    1994-01-01

    Naturally occurring gas hydrate is found in sediment of two regions: (1) continental, including continental shelves, at high latitudes where surface temperatures are very cold, and (2) submarine outer continental margins where pressures are very high and bottom-water temperatures are near 0??C. Continental gas hydrate is found in association with onshore and offshore permafrost. Submarine gas hydrate is found in sediment of continental slopes and rises. The amount of methane present in gas hydrate is thought to be very large, but the estimates that have been made are more speculative than real. Nevertheless, at the present time there has been a convergence of ideas regarding the amount of methane in gas hydrate deposits worldwide at about 2 x 1016 m3 or 7 x 1017 ft3 = 7 x 105 Tcf [Tcf = trillion (1012) ft3]. The potentially large amount of methane in gas hydrate and the shallow depth of gas hydrate deposits are two of the principal factors driving research concerning this substance. Such a large amount of methane, if it could be commercially produced, provides a potential energy resource for the future. Because gas hydrate is metastable, changes of surface pressure and temperature affect its stability. Destabilized gas hydrate beneath the sea floor leads to geologic hazards such as submarine mass movements. Examples of submarine slope failures attributed to gas hydrate are found worldwide. The metastability of gas hydrate may also have an effect on climate. The release of methane, a 'greenhouse' gas, from destabilized gas hydrate may contribute to global warming and be a factor in global climate change.

  10. Cation-Induced Hydration Effects Cause Lower Critical Solution Temperature Behavior in Protein Solutions.

    PubMed

    Matsarskaia, Olga; Braun, Michal K; Roosen-Runge, Felix; Wolf, Marcell; Zhang, Fajun; Roth, Roland; Schreiber, Frank

    2016-08-11

    The phase behavior of protein solutions is important for numerous phenomena in biology and soft matter. We report a lower critical solution temperature (LCST) phase behavior of aqueous solutions of a globular protein induced by multivalent metal ions around physiological temperatures. The LCST behavior manifests itself via a liquid-liquid phase separation of the protein-salt solution upon heating. Isothermal titration calorimetry and zeta-potential measurements indicate that here cation-protein binding is an endothermic, entropy-driven process. We offer a mechanistic explanation of the LCST. First, cations bind to protein surface groups driven by entropy changes of hydration water. Second, the bound cations bridge to other protein molecules, inducing an entropy-driven attraction causing the LCST. Our findings have general implications for condensation, LCST, and hydration behavior of (bio)polymer solutions as well as the understanding of biological effects of (heavy) metal ions and their hydration. PMID:27414502

  11. Polycrystalline methane hydrate: Synthesis from superheated ice, and low-temperature mechanical properties

    USGS Publications Warehouse

    Stern, L.A.; Kirby, S.H.; Durham, W.B.

    1998-01-01

    We describe a new and efficient technique to grow aggregates of pure methane hydrate in quantities suitable for physical and material properties testing. Test specimens were grown under static conditions by combining cold, pressurized CH4 gas with granulated H2O ice, and then warming the reactants to promote the reaction CH4(g) + 6H2O(s???1) ??? CH4??6H2O (methane hydrate). Hydrate formation evidently occurs at the nascent ice/liquid water interface on ice grain surfaces, and complete reaction was achieved by warming the system above the ice melting point and up to 290 K, at 25-30 MPa, for approximately 8 h. The resulting material is pure, cohesive, polycrystalline methane hydrate with controlled grain size and random orientation. Synthesis conditions placed the H2O ice well above its melting temperature while reaction progressed, yet samples and run records showed no evidence for bulk melting of the unreacted portions of ice grains. Control experiments using Ne, a non-hydrate-forming gas, showed that under otherwise identical conditions, the pressure reduction and latent heat associated with ice melting are easily detectable in our fabrication apparatus. These results suggest that under hydrate-forming conditions, H2O ice can persist metastably to temperatures well above its ordinary melting point while reacting to form hydrate. Direct observations of the hydrate growth process in a small, high-pressure optical cell verified these conclusions and revealed additional details of the hydrate growth process. Methane hydrate samples were then tested in constant-strain-rate deformation experiments at T = 140-200 K, Pc = 50-100 MPa, and ?? = 10-4 10-6 s-1. Measurements in both the brittle and ductile fields showed that methane hydrate has measurably different strength than H2O ice, and work hardens to an unusually high degree compared to other ices as well as to most metals and ceramics at high homologous temperatures. This work hardening may be related to a changing

  12. Desalination utilizing clathrate hydrates (LDRD final report).

    SciTech Connect

    Simmons, Blake Alexander; Bradshaw, Robert W.; Dedrick, Daniel E.; Cygan, Randall Timothy; Greathouse, Jeffery A.; Majzoub, Eric H.

    2008-01-01

    Advances are reported in several aspects of clathrate hydrate desalination fundamentals necessary to develop an economical means to produce municipal quantities of potable water from seawater or brackish feedstock. These aspects include the following, (1) advances in defining the most promising systems design based on new types of hydrate guest molecules, (2) selection of optimal multi-phase reactors and separation arrangements, and, (3) applicability of an inert heat exchange fluid to moderate hydrate growth, control the morphology of the solid hydrate material formed, and facilitate separation of hydrate solids from concentrated brine. The rate of R141b hydrate formation was determined and found to depend only on the degree of supercooling. The rate of R141b hydrate formation in the presence of a heat exchange fluid depended on the degree of supercooling according to the same rate equation as pure R141b with secondary dependence on salinity. Experiments demonstrated that a perfluorocarbon heat exchange fluid assisted separation of R141b hydrates from brine. Preliminary experiments using the guest species, difluoromethane, showed that hydrate formation rates were substantial at temperatures up to at least 12 C and demonstrated partial separation of water from brine. We present a detailed molecular picture of the structure and dynamics of R141b guest molecules within water cages, obtained from ab initio calculations, molecular dynamics simulations, and Raman spectroscopy. Density functional theory calculations were used to provide an energetic and molecular orbital description of R141b stability in both large and small cages in a structure II hydrate. Additionally, the hydrate of an isomer, 1,2-dichloro-1-fluoroethane, does not form at ambient conditions because of extensive overlap of electron density between guest and host. Classical molecular dynamics simulations and laboratory trials support the results for the isomer hydrate. Molecular dynamics simulations

  13. Natural gas production from Arctic gas hydrates

    SciTech Connect

    Collett, T.S. )

    1993-01-01

    The natural gas hydrates of the Messoyakha field in the West Siberian basin of Russia and those of the Prudhoe Bay-Kuparuk River area on the North Slope of Alaska occur within a similar series of interbedded Cretaceous and Tertiary sandstone and siltstone reservoirs. Geochemical analyses of gaseous well-cuttings and production gases suggest that these two hydrate accumulations contain a mixture of thermogenic methane migrated from a deep source and shallow, microbial methane that was either directly converted to gas hydrate or was first concentrated in existing traps and later converted to gas hydrate. Studies of well logs and seismic data have documented a large free-gas accumulation trapped stratigraphically downdip of the gas hydrates in the Prudhoe Bay-Kuparuk River area. The presence of a gas-hydrate/free-gas contact in the Prudhoe Bay-Kuparuk River area is analogous to that in the Messoyakha gas-hydrate/free-gas accumulation, from which approximately 5.17x10[sup 9] cubic meters (183 billion cubic feet) of gas have been produced from the hydrates alone. The apparent geologic similarities between these two accumulations suggest that the gas-hydrated-depressurization production method used in the Messoyakha field may have direct application in northern Alaska. 30 refs., 15 figs., 3 tabs.

  14. Physical Properties of Gas Hydrates: A Review

    DOE PAGESBeta

    Gabitto, Jorge F.; Tsouris, Costas

    2010-01-01

    Memore » thane gas hydrates in sediments have been studied by several investigators as a possible future energy resource. Recent hydrate reserves have been estimated at approximately 10 16   m 3 of methane gas worldwide at standard temperature and pressure conditions. In situ dissociation of natural gas hydrate is necessary in order to commercially exploit the resource from the natural-gas-hydrate-bearing sediment. The presence of gas hydrates in sediments dramatically alters some of the normal physical properties of the sediment. These changes can be detected by field measurements and by down-hole logs. An understanding of the physical properties of hydrate-bearing sediments is necessary for interpretation of geophysical data collected in field settings, borehole, and slope stability analyses; reservoir simulation; and production models. This work reviews information available in literature related to the physical properties of sediments containing gas hydrates. A brief review of the physical properties of bulk gas hydrates is included. Detection methods, morphology, and relevant physical properties of gas-hydrate-bearing sediments are also discussed.« less

  15. Physical Properties of Gas Hydrates: A Review

    SciTech Connect

    Gabitto, Jorge; Tsouris, Costas

    2010-01-01

    Methane gas hydrates in sediments have been studied by several investigators as a possible future energy resource. Recent hydrate reserves have been estimated at approximately 1016?m3 of methane gas worldwide at standard temperature and pressure conditions. In situ dissociation of natural gas hydrate is necessary in order to commercially exploit the resource from the natural-gas-hydrate-bearing sediment. The presence of gas hydrates in sediments dramatically alters some of the normal physical properties of the sediment. These changes can be detected by field measurements and by down-hole logs. An understanding of the physical properties of hydrate-bearing sediments is necessary for interpretation of geophysical data collected in field settings, borehole, and slope stability analyses; reservoir simulation; and production models. This work reviews information available in literature related to the physical properties of sediments containing gas hydrates. A brief review of the physical properties of bulk gas hydrates is included. Detection methods, morphology, and relevant physical properties of gas-hydrate-bearing sediments are also discussed.

  16. Waters of Hydration of Cupric Hydrates: A Comparison between Heating and Absorbance Methods

    ERIC Educational Resources Information Center

    Barlag, Rebecca; Nyasulu, Frazier

    2011-01-01

    The empirical formulas of four cupric hydrates are determined by measuring the absorbance in aqueous solution. The Beer-Lambert Law is verified by constructing a calibration curve of absorbance versus known Cu[superscript 2+](aq) concentration. A solution of the unknown hydrate is prepared by using 0.2-0.3 g of hydrate, and water is added such…

  17. Observations related to tetrahydrofuran and methane hydrates for laboratory studies of hydrate-bearing sediments

    NASA Astrophysics Data System (ADS)

    Lee, J. Y.; Yun, T. S.; Santamarina, J. C.; Ruppel, C.

    2007-06-01

    The interaction among water molecules, guest gas molecules, salts, and mineral particles determines the nucleation and growth behavior of gas hydrates in natural sediments. Hydrate of tetrahydrofuran (THF) has long been used for laboratory studies of gas hydrate-bearing sediments to provide close control on hydrate concentrations and to overcome the long formation history of methane hydrate from aqueous phase methane in sediments. Yet differences in the polarizability of THF (polar molecule) compared to methane (nonpolar molecule) raise questions about the suitability of THF as a proxy for methane in the study of hydrate-bearing sediments. From existing data and simple macroscale experiments, we show that despite its polar nature, THF's large molecular size results in low permittivity, prevents it from dissolving precipitated salts, and hinders the solvation of ions on dry mineral surfaces. In addition, the interfacial tension between water and THF hydrate is similar to that between water and methane hydrate. The processes that researchers choose for forming hydrate in sediments in laboratory settings (e.g., from gas, liquid, or ice) and the pore-scale distribution of the hydrate that is produced by each of these processes likely have a more pronounced effect on the measured macroscale properties of hydrate-bearing sediments than do differences between THF and methane hydrates themselves.

  18. Observations related to tetrahydrofuran and methane hydrates for laboratory studies of hydrate-bearing sediments

    USGS Publications Warehouse

    Lee, J.Y.; Yun, T.S.; Santamarina, J.C.; Ruppel, C.

    2007-01-01

    The interaction among water molecules, guest gas molecules, salts, and mineral particles determines the nucleation and growth behavior of gas hydrates in natural sediments. Hydrate of tetrahydrofuran (THF) has long been used for laboratory studies of gas hydrate-bearing sediments to provide close control on hydrate concentrations and to overcome the long formation history of methane hydrate from aqueous phase methane in sediments. Yet differences in the polarizability of THF (polar molecule) compared to methane (nonpolar molecule) raise questions about the suitability of THF as a proxy for methane in the study of hydrate-bearing sediments. From existing data and simple macroscale experiments, we show that despite its polar nature, THF's large molecular size results in low permittivity, prevents it from dissolving precipitated salts, and hinders the solvation of ions on dry mineral surfaces. In addition, the interfacial tension between water and THF hydrate is similar to that between water and methane hydrate. The processes that researchers choose for forming hydrate in sediments in laboratory settings (e.g., from gas, liquid, or ice) and the pore-scale distribution of the hydrate that is produced by each of these processes likely have a more pronounced effect on the measured macroscale properties of hydrate-bearing sediments than do differences between THF and methane hydrates themselves.

  19. Total sulphate vs. sulphuric acid monomer in nucleation studies

    NASA Astrophysics Data System (ADS)

    Neitola, K.; Brus, D.; Makkonen, U.; Sipilä, M.; Mauldin, R. L., III; Sarnela, N.; Jokinen, T.; Lihavainen, H.; Kulmala, M.

    2014-10-01

    Sulphuric acid is known to be a key component for atmospheric nucleation. Precise determination of sulphuric acid concentration is crucial factor for prediction of nucleation rates and subsequent growth. In our study, we have noticed a substantial discrepancy between sulphuric acid monomer and total sulphate concentrations measured from the same source of sulphuric acid vapour. The discrepancy of about one to two orders of magnitude was found with similar formation rates. To investigate this discrepancy and its effect on nucleation, a method of thermally controlled saturator filled with pure sulphuric acid (97% wt.) for production of sulphuric acid vapour is introduced and tested. Sulphuric acid-water nucleation experiment was done using a laminar flow tube. Two independent methods of mass spectrometry and online ion chromatography were used for detecting sulphuric acid concentrations. The results are compared to our previous results, where a method of furnace was used to produce sulphuric acid vapour (Brus et al., 2010, 2011). Measured sulphuric acid concentrations are compared to theoretical prediction calculated using vapour pressure and a mixing law. The calculated prediction of sulphuric acid concentrations agrees very well with the measured values when total sulphate is considered. Sulphuric acid monomer concentration was found to be about two orders of magnitude lower than the prediction, but with similar temperature dependency as the prediction and the results obtained with ion chromatograph method. Formation rates agree well when compared to our previous results with both sulphuric acid detection and sulphuric acid production methods separately.

  20. Topological crystallography of gas hydrates.

    PubMed

    Gudkovskikh, Sergey V; Kirov, Mikhail V

    2015-07-01

    A new approach to the investigation of the proton-disordered structure of clathrate hydrates is presented. This approach is based on topological crystallography. The quotient graphs were built for the unit cells of the cubic structure I and the hexagonal structure H. This is a very convenient way to represent the topology of a hydrogen-bonding network under periodic boundary conditions. The exact proton configuration statistics for the unit cells of structure I and structure H were obtained using the quotient graphs. In addition, the statistical analysis of the proton transfer along hydrogen-bonded chains was carried out. PMID:26131899

  1. A coupled THMC model of a heating and hydration laboratory experiment in unsaturated compacted FEBEX bentonite

    SciTech Connect

    Zheng, L.; Samper, J.; Montenegro, L.; Fernandez, A.M.

    2010-05-01

    Unsaturated compacted bentonite is foreseen by several countries as a backfill and sealing material in high-level radioactive waste repositories. The strong interplays between thermal (T), hydrodynamic (H), mechanical (M) and chemical (C) processes during the hydration stage of a repository call for fully coupled THMC models. Validation of such THMC models is prevented by the lack of comprehensive THMC experiments and the difficulties of experimental methods to measure accurately the chemical composition of bentonite porewater. We present here a non-isothermal multiphase flow and multicomponent reactive solute transport model for a deformable medium of a heating and hydration experiment performed on a sample of compacted FEBEX bentonite. Besides standard solute transport and geochemical processes, the model accounts for solute cross diffusion and thermal and chemical osmosis. Bentonite swelling is solved with a state-surface approach. The THM model is calibrated with transient temperature, water content and porosity data measured at the end of the experiment. The reactive transport model is calibrated with porewater chemical data derived from aqueous extract data. Model results confirm that thermal osmosis is relevant for the hydration of FEBEX bentonite while chemical osmosis can be safely neglected. Dilution and evaporation are the main processes controlling the concentration of conservative species. Dissolved cations are mostly affected by calcite dissolution-precipitation and cation exchange reactions. Dissolved sulphate is controlled by gypsum/anhydrite dissolution-precipitation. pH is mostly buffered by protonation/deprotonation via surface complexation. Computed concentrations agree well with inferred aqueous extract data at all sections except near the hydration boundary where cation data are affected by a sampling artifact. The fit of Cl{sup -} data is excellent except for the data near the heater. The largest deviations of the model from inferred aqueous

  2. A coupled THMC model of a heating and hydration laboratory experiment in unsaturated compacted FEBEX bentonite

    NASA Astrophysics Data System (ADS)

    Zheng, Liange; Samper, Javier; Montenegro, Luis; Fernández, Ana María

    2010-05-01

    SummaryUnsaturated compacted bentonite is foreseen by several countries as a backfill and sealing material in high-level radioactive waste repositories. The strong interplays between thermal (T), hydrodynamic (H), mechanical (M) and chemical (C) processes during the hydration stage of a repository call for fully coupled THMC models. Validation of such THMC models is prevented by the lack of comprehensive THMC experiments and the difficulties of experimental methods to measure accurately the chemical composition of bentonite porewater. We present here a non-isothermal multiphase flow and multicomponent reactive solute transport model for a deformable medium of a heating and hydration experiment performed on a sample of compacted FEBEX bentonite. Besides standard solute transport and geochemical processes, the model accounts for solute cross diffusion and thermal and chemical osmosis. Bentonite swelling is solved with a state-surface approach. The THM model is calibrated with transient temperature, water content and porosity data measured at the end of the experiment. The reactive transport model is calibrated with porewater chemical data derived from aqueous extract data. Model results confirm that thermal osmosis is relevant for the hydration of FEBEX bentonite while chemical osmosis can be safely neglected. Dilution and evaporation are the main processes controlling the concentration of conservative species. Dissolved cations are mostly affected by calcite dissolution-precipitation and cation exchange reactions. Dissolved sulphate is controlled by gypsum/anhydrite dissolution-precipitation. pH is mostly buffered by protonation/deprotonation via surface complexation. Computed concentrations agree well with inferred aqueous extract data at all sections except near the hydration boundary where cation data are affected by a sampling artifact. The fit of Cl - data is excellent except for the data near the heater. The largest deviations of the model from inferred

  3. Determination of the elemental composition of molasses and its suitability as carbon source for growth of sulphate-reducing bacteria.

    PubMed

    Teclu, Daniel; Tivchev, George; Laing, Mark; Wallis, Mike

    2009-01-30

    Bioremediation of arsenic-contaminated water could be a cost-effective process provided a cheap carbon source is used. In this work molasses was tested as a possible source of carbon for the growth of sulphate-reducing bacteria (SRB). Its elemental composition and the tolerance of SRB toward different arsenic species (As (III) and As (V)) were also investigated. Batch studies were carried out to assess the suitability of 1, 2.5 and 5 g/l molasses concentrations for SRB growth. The results indicated that molasses does support SRB growth, the level of response being dependant on the concentration. The percentage of sulphate reduction with molasses at 1, 2.5 and 5 g/l was not significantly different. However, growth on molasses was not as good as that obtained when lactate was used as carbon source. Molasses contained the heavy metals Al, As, Cu, Fe, Mn and Zn in concentrations of 0.54, 0.24, 8.7, 0.35, 11.1 and 19.7 microg/g, respectively. Arsenic tolerance, growth response and sulphate-reducing activity of the SRB were investigated using arsenite and arsenate solutions at final concentrations of 1, 5 and 20 mg/l for each species. The results revealed that very little SRB growth occurred at concentrations of 20 mg/l As(III) or As(V). At lower concentrations (1 mg/l) the SRB grew better with As(V) than with As(III). Arsenic pollution in most groundwater sources is below this level (1 mg/l).

  4. D/H fractionation in sulfate hydrate-water systems

    SciTech Connect

    Pradhananga, T.M.; Matsuo, S.

    1985-05-09

    The D/H fractionation factors (..cap alpha..) of some of the sulfate hydrate-water systems were measured. A dependence of ..cap alpha.. on cationic parameters and M-H/sub 2/O distance was found. The D/H fractionation factors of various hydrate-water systems were divided into two groups with respect to their ..cap alpha.. values: one having ..cap alpha.. < 1 and the other ..cap alpha.. > 1. There is almost no change in ..cap alpha.. for crystal-water systems having SO/sub 4//sup 2 -/ as the anion of the first transition metallic ion series from Fe/sup 2 +/ to Zn/sup 2 +/ except for Cu/sup 2 +/. The result is related to the common structure of the hydration sphere of cations and the common distance of M-H/sub 2/O. The exceptional case for Cu/sup 2 +/ is attributed to the distorted structure of octahedra surrounding Cu/sup 2 +/. A similar type of behavior of protons leading to the residual entropy has been found in some of the crystal-water systems having ..cap alpha.. > 1. 45 references, 3 figures, 3 tables.

  5. Hydration Dynamics of Biomolecules from Co-solvents to Crowding

    NASA Astrophysics Data System (ADS)

    Kubarych, Kevin

    Biomolecules self-assemble into complex functional structures with high fidelity largely due to interactions between the macromolecules and water. Once folded, the dynamics of water molecules in the vicinity of extended macromolecular interfaces can be altered relative to the bulk, leading to complex, heterogeneous and distance-dependent transport properties near these surfaces. Using a strategy based on transition metal carbonyl vibrational probes covalently conjugated to the protein surface, we have been able to use ultrafast two-dimensional infrared (2D-IR) spectroscopy to probe the dynamics from this most important perspective. In a series of studies, we have found these probes to be primarily sensitive to the orientational dynamics of the hydrating water molecules, and have studied both protein/water and membrane/water interfaces. Several key finding have emerged, including a modest 2-3-fold slowdown of hydration water's reorientational dynamics relative to the bulk, and a dynamical transition that occurs due to collective hydration induced by macromolecular crowding. We will summarize our progress to-date, as well as present our newest results on the effects of ions and the dynamical signatures of preferential solvation.

  6. Gas hydrates in ocean bottom sediments

    SciTech Connect

    MacLeod, M.K.

    1982-12-01

    Gas hydrates belong to a special category of chemical substances known as inclusion compounds. An inclusion compound is a physical combination of molecules in which one component becomes trapped inside the other. In gas hydrates, gas molecules are physically trapped inside an expanded lattice of water molecules. The pressures and temperatures beneath Artic water depths greater than 1,100 ft (335 m) and subtropical water depths greater than 2,000 ft (610 m) are suitable for the formation of methane hydrate. Theoretical depths to the base of a gas hydrate layer in ocean bottom sediments are determined by assuming: (1) a constant hydrostatic pressure gradient, (2) two typical hydrothermal gradients, (3) variable geothermal gradients, and (4) pure methane hydrated with connate seawater. In addition to pressure and geothermal gradient, other variables affecting the stability of gas hydrate are examined. These variables are hydrothermal gradient, sediment thermal conductivity, heat flow, hydrate velocity, gas composition, and connate water salinity. If these variables are constant in a lateral direction and the above assmptions are valid, a local geothermal gradient can be determined if the depth to the base of a gas hydrate is known. The base of the gas hydrate layer is seen on seismic profiles as an anomalous reflection nearly parallel to the ocean bottom, cross-cutting geologic bedding plane reflections, and generally increasing in sub-ocean bottom time with increasing water depth. The acoustic impedance is a result of the relatively fast velocity hydrate layer overlying slower velocity sediments. In addition, free gas may be trapped beneath the hydrate, thereby enhancing the reflection.

  7. Methane hydrate research at NETL: Research to make methane production from hydrates a reality

    SciTech Connect

    Taylor, C.E.; Link, D.D.; English, N.

    2007-03-01

    Research is underway at NETL to understand the physical properties of methane hydrates. Five key areas of research that need further investigation have been identified. These five areas, i.e. thermal properties of hydrates in sediments, kinetics of natural hydrate dissociation, hysteresis effects, permeability of sediments to gas flow and capillary pressures within sediments, and hydrate distribution at porous scale, are important to the production models that will be used for producing methane from hydrate deposits. NETL is using both laboratory experiments and computational modeling to address these five key areas. The laboratory and computational research reinforce each other by providing feedback. The laboratory results are used in the computational models and the results from the computational modeling is used to help direct future laboratory research. The data generated at NETL will be used to help fulfill The National Methane Hydrate R&D Program of a “long-term supply of natural gas by developing the knowledge and technology base to allow commercial production of methane from domestic hydrate deposits by the year 2015” as outlined on the NETL Website [NETL Website, 2005. http://www.netl.doe.gov/scngo/Natural%20Gas/hydrates/index.html]. Laboratory research is accomplished in one of the numerous high-pressure hydrate cells available ranging in size from 0.15 mL to 15 L in volume. A dedicated high-pressure view cell within the Raman spectrometer allows for monitoring the formation and dissociation of hydrates. Thermal conductivity of hydrates (synthetic and natural) at a certain temperature and pressure is performed in a NETL-designed cell. Computational modeling studies are investigating the kinetics of hydrate formation and dissociation, modeling methane hydrate reservoirs, molecular dynamics simulations of hydrate formation, dissociation, and thermal properties, and Monte Carlo simulations of hydrate formation and dissociation.

  8. Termination and hydration of forsteritic olivine (0 1 0) surface

    NASA Astrophysics Data System (ADS)

    Yan, Hongping; Park, Changyong; Ahn, Gun; Hong, Seungbum; Keane, Denis T.; Kenney-Benson, Curtis; Chow, Paul; Xiao, Yuming; Shen, Guoyin

    2014-11-01

    Termination and hydration of the forsteritic (Fo90Fa10) olivine (0 1 0) surface have been investigated with high-resolution specular X-ray reflectivity and Atomic Force Microscopy. The surface was prepared by polishing a naturally grown {0 1 0} face, from which we found the polished surface in acidic (pH 3.5) alumina suspension exhibits regular steps while the basic (pH 9.5) silica polished surface is irregularly roughened, indicating there are two distinguishable mechanochemical processes for the surface dissolution. The quantitative interpretation of the regular steps from the alumina-polished surface suggests that the observed step heights correspond to multiples of crystallographic unit cell. Only this atomically terraced surface is investigated with the high-resolution X-ray reflectivity (HRXR) to determine the surface termination and hydration. The basic silica paste polished surface turned out too rough to measure with X-ray reflectivity. HRXR reveals that the alumina polished olivine (0 1 0) surface in pure water is terminated at a plane including half-occupied metal ion sites (M1), an oxygen vacancy site, and a silicate tetrahedral unit with one of its apices pointing outward with respect to the surface. An ideal termination with the oxygen vacancy would fulfill the stoichiometry of the formula unit; however, in the observation, the vacancy site is filled by an adsorbed water species and about a quarter of the remaining metal ions are further depleted. The terminating plane generates two distinct atomic layers in the laterally averaged electron density profile, on which two highly ordered adsorbed water layers are formed. The first layer formation is likely through the direct interaction with the M1 plane and the second layer is likely through the hydrogen bonding interaction with the first water layer. With this multilayered adsorbed water structure, the surface metal ion is partially hydrated by the vacancy-filling water species and adsorbed water

  9. DNA hydration studied by neutron fiber diffraction

    SciTech Connect

    Fuller, W.; Forsyth, V.T.; Mahendrasingam, A.; Langan, P.; Pigram, W.J.

    1994-12-31

    The development of neutron high angle fiber diffraction to investigate the location of water around the deoxyribonucleic acid (DNA) double-helix is described. The power of the technique is illustrated by its application to the D and A conformations of DNA using the single crystal diffractometer, D19, at the Institute Laue-Langevin, Grenoble and the time of flight diffractometer, SXD, at the Rutherford Appleton ISIS Spallation Neutron Source. These studies show the existence of bound water closely associated with the DNA. The patterns of hydration in these two DNA conformations are quite distinct and are compared to those observed in X-ray single crystal studies of two-stranded oligodeoxynucleotides. Information on the location of water around the DNA double-helix from the neutron fiber diffraction studies is combined with that on the location of alkali metal cations from complementary X-ray high angle fiber diffraction studies at the Daresbury Laboratory SRS using synchrotron radiation. These analyses emphasize the importance of viewing DNA, water and ions as a single system with specific interactions between the three components and provide a basis for understanding the effect of changes in the concentration of water and ions in inducing conformations] transitions in the DNA double-helix.

  10. Synthesis of polycrystalline methane hydrate, and its phase stability and mechanical properties at elevated pressure

    USGS Publications Warehouse

    Stern, L.A.; Kirby, S.H.; Durham, W.B.

    1997-01-01

    Test specimens of methane hydrate were grown under static conditions by combining cold, pressurized CH4 gas with H2O ice grains, then warming the system to promote the reaction CH4 (g) + 6H2O (s???l) ??? CH4??6H2O. Hydrate formation evidently occurs at the nascent ice/liquid water interface, and complete reaction was achieved by warming the system above 271.5 K and up to 289 K, at 25-30 MPa, for approximately 8 hours. The resulting material is pure methane hydrate with controlled grain size and random texture. Fabrication conditions placed the H2O ice well above its melting temperature before reaction completed, yet samples and run records showed no evidence for bulk melting of the ice grains. Control experiments using Ne, a non-hydrate-forming gas, verified that under otherwise identical conditions, the pressure reduction and latent heat associated with ice melting is easily detectable in our fabrication apparatus. These results suggest that under hydrate-forming conditions, H2O ice can persist metastably at temperatures well above its melting point. Methane hydrate samples were then tested in constant-strain-rate deformation experiments at T= 140-200 K, Pc= 50-100 MPa, and ????= 10-4-10-6 s-1. Measurements in both the brittle and ductile fields showed that methane hydrate has measurably different strength than H2O ice, and work hardens to a higher degree compared to other ices as well as to most metals and ceramics at high homologous temperatures. This work hardening may be related to a changing stoichiometry under pressure during plastic deformation; x-ray analyses showed that methane hydrate undergoes a process of solid-state disproportionation or exsolution during deformation at conditions well within its conventional stability field.

  11. Massive Volcanic SO2 Oxidation and Sulphate Aerosol Deposition in Cenozoic North America

    EPA Science Inventory

    Volcanic eruptions release a large amount of sulphur dioxide (SO2) into the atmosphere. SO2 is oxidized to sulphate and can subsequently form sulphate aerosol, which can affect the Earth's radiation balance, biologic productivity and high-altitude ozone co...

  12. Effect of aerobic exercise against vanadyl sulphate-induced nephrotoxicity and hepatotoxicity in rats

    PubMed Central

    Ahmadi, Fatemeh; Nematbakhsh, Mehdi; Kargarfard, Mehdi; Eshraghi-Jazi, Fatemeh; Talebi, Ardeshir; Shirdavani, Soheila

    2016-01-01

    Introduction: Vanadium compounds are insulin like drugs which are accompanied with nephrotoxicity and hepatotoxicity as their major side effects. Aerobic exercise is well known as an approach to reduce the side effects of many drugs. Objectives: This study was designed to determine the role of aerobic exercise against vanadyl sulphate induced nephrotoxicity and hepatotoxicity in male rats. Materials and Methods: Twenty-four male Wistar rats were randomly divided into three groups. Group I had aerobic exercise on a treadmill 5 days/week for 6 weeks. Group II received vanadyl sulphate (50 mg/kg/week; i.p.) for 6 weeks. Group III had combination of exercise and vanadyl sulphate therapy as groups 1 and 2. At the end of study, blood samples were obtained, and the animals were sacrificed for the tissues injury determination. Results: Vanadyl sulphate alone increased serum levels of blood urea nitrogen (BUN), creatinine (Cr), and kidney weight (KW) and kidney tissue damage score (KTDS) (P<0.05). These observations revealed nephrotoxicity induced by vanadyl sulphate, although exercise training did not attenuate these results. In addition, vanadyl sulphate alone induced liver tissue damage score and exercise training intensified it insignificantly, while the serum levels of aspartate amino transferase and alanine amino transferase were greater in exercise alone group than others groups. Conclusion: Aerobic exercise could not attenuate vanadyl sulphate induced nephrotoxicity and hepatotoxicity. These findings must be considered when vanadyl sulphate is suggested as insulin like drug. PMID:27689120

  13. Local absorption of zinc from wounds treated with different concentrations of zinc sulphate.

    PubMed

    Hallmans, G

    1978-01-01

    In the present study it was shown in rats that zinc is absorbed from excisional wounds treated with zinc sulphate. Systemic toxic effects were observed in the group treated with 20% zinc sulphate. Local toxic effects were seen in wounds treated with 0.2%, 2% and 20% zinc sulphate. An inhibitory effect of zinc on the migration of granulocytes was suggested on the basis of microscopic observation. In the operated groups which were not treated with zinc and the group treated with 0.02% zinc sulphate a decline was observed in the concentration of zinc in serum. The zinc concentration in serum increased in proportion to the zinc sulphate concentration (0.2%, 2% and 20%) applied to the wounds, while the copper concentration decreased in the groups treated with 2% and 20% zinc sulphate. In all operated groups an increase in zinc and copper concentrations was observed in liver. This was most pronounced in groups treated with higher concentrations of zinc sulphate (0.2%, 2% and 20%). The groups treated with higher concentrations of zinc sulphate also had higher pancreas zinc concentrations than the remaining groups.

  14. 13C-n.m.r. analysis of some sulphate derivatives of chitosan.

    PubMed

    Hirano, S; Hasegawa, M; Kinugawa, J

    1991-10-01

    Positions of substitution with sulphate in three water-soluble sulphated derivatives of chitosan were analysed by 13C n.m.r. The structures of N-acetylchitosan 3,6-O-disulphate, sodium chitosan N-, 6-O-disulphate, and sodium chitosan 6-O-monosulphate were confirmed.

  15. Effect of aerobic exercise against vanadyl sulphate-induced nephrotoxicity and hepatotoxicity in rats

    PubMed Central

    Ahmadi, Fatemeh; Nematbakhsh, Mehdi; Kargarfard, Mehdi; Eshraghi-Jazi, Fatemeh; Talebi, Ardeshir; Shirdavani, Soheila

    2016-01-01

    Introduction: Vanadium compounds are insulin like drugs which are accompanied with nephrotoxicity and hepatotoxicity as their major side effects. Aerobic exercise is well known as an approach to reduce the side effects of many drugs. Objectives: This study was designed to determine the role of aerobic exercise against vanadyl sulphate induced nephrotoxicity and hepatotoxicity in male rats. Materials and Methods: Twenty-four male Wistar rats were randomly divided into three groups. Group I had aerobic exercise on a treadmill 5 days/week for 6 weeks. Group II received vanadyl sulphate (50 mg/kg/week; i.p.) for 6 weeks. Group III had combination of exercise and vanadyl sulphate therapy as groups 1 and 2. At the end of study, blood samples were obtained, and the animals were sacrificed for the tissues injury determination. Results: Vanadyl sulphate alone increased serum levels of blood urea nitrogen (BUN), creatinine (Cr), and kidney weight (KW) and kidney tissue damage score (KTDS) (P<0.05). These observations revealed nephrotoxicity induced by vanadyl sulphate, although exercise training did not attenuate these results. In addition, vanadyl sulphate alone induced liver tissue damage score and exercise training intensified it insignificantly, while the serum levels of aspartate amino transferase and alanine amino transferase were greater in exercise alone group than others groups. Conclusion: Aerobic exercise could not attenuate vanadyl sulphate induced nephrotoxicity and hepatotoxicity. These findings must be considered when vanadyl sulphate is suggested as insulin like drug.

  16. Isotopic evidence for microbial sulphate reduction in the early Archaean era.

    PubMed

    Shen, Y; Buick, R; Canfield, D E

    2001-03-01

    Sulphate-reducing microbes affect the modern sulphur cycle, and may be quite ancient, though when they evolved is uncertain. These organisms produce sulphide while oxidizing organic matter or hydrogen with sulphate. At sulphate concentrations greater than 1 mM, the sulphides are isotopically fractionated (depleted in 34S) by 10-40/1000 compared to the sulphate, with fractionations decreasing to near 0/1000 at lower concentrations. The isotope record of sedimentary sulphides shows large fractionations relative to seawater sulphate by 2.7 Gyr ago, indicating microbial sulphate reduction. In older rocks, however, much smaller fractionations are of equivocal origin, possibly biogenic but also possibly volcanogenic. Here we report microscopic sulphides in approximately 3.47-Gyr-old barites from North Pole, Australia, with maximum fractionations of 21.1/1000, about a mean of 11.6/1000, clearly indicating microbial sulphate reduction. Our results extend the geological record of microbial sulphate reduction back more than 750 million years, and represent direct evidence of an early specific metabolic pathway--allowing time calibration of a deep node on the tree of life.

  17. Expression of genes encoding for proteins involved in heparan sulphate and chondroitin sulphate chain synthesis and modification in normal and malignant plasma cells.

    PubMed

    Bret, Caroline; Hose, Dirk; Reme, Thierry; Sprynski, Anne-Catherine; Mahtouk, Karène; Schved, Jean-François; Quittet, Philippe; Rossi, Jean-François; Goldschmidt, Hartmut; Klein, Bernard

    2009-05-01

    Syndecan-1 is a proteoglycan that concentrates heparin-binding factors on the surface of multiple myeloma cells, and probably plays a major role in multiple myeloma biology. As heparan sulphate and chondroitin sulphate are the bioactive components of syndecan-1, we analysed the signature of genes encoding 100 proteins involved in synthesis of these chains, i.e. from precursor uptake to post-translational modifications, using Affymetrix microarrays. The expression of enzymes required for heparan sulphate and chondroitin sulphate biosynthesis was shown to increase in parallel with syndecan-1 expression, throughout the differentiation of memory B cells into plasmablasts and normal bone marrow plasma cells. Sixteen genes were significantly different between normal and malignant plasma cells, nine of these genes -EXT2, CHSY3, CSGALNACT1, HS3ST2, HS2ST1, CHST11, CSGALNACT2, HPSE, SULF2 - encode proteins involved in glycosaminoglycan chain synthesis or modifications. Kaplan-Meier analysis was performed in two independent series of patients: B4GALT7, CSGALNACT1, HS2ST1 were associated with a good prognosis whereas EXT1 was linked to a bad prognosis. This study provides an overall picture of the major genes encoding for proteins involved in heparan sulphate and chondroitin sulphate synthesis and modifications that can be implicated in normal and malignant plasma cells. PMID:19298595

  18. Vibrational lifetimes of hydrated phospholipids

    NASA Astrophysics Data System (ADS)

    Jadidi, Tayebeh; Anvari, Mehrnaz; Mashaghi, Alireza; Sahimi, Muhammad; Rahimi Tabar, M. Reza

    2013-04-01

    Large-scale ab initio molecular-dynamics simulations have been carried out to compute, at human-body temperature, the vibrational modes and lifetimes of pure and hydrated dipalmitoylphosphatidylcholine (DPPC) lipids. The projected atomic vibrations calculated from the spectral energy density are used to compute the vibrational modes and the lifetimes. All the normal modes of the pure and hydrated DPPC and their frequencies are identified. The computed lifetimes incorporate the full anharmonicity of the atomic interactions. The vibrational modes of the water molecules close to the head group of DPPC are active (possess large projected spectrum amplitudes) in the frequency range 0.5-55 THz, with a peak at 2.80 THz in the energy spectrum. The computed lifetimes for the high-frequency modes agree well with the recent data measured at room temperature where high-order phonon scattering is not negligible. The computed lifetimes of the low-frequency modes can be tested using the current experimental capabilities. Moreover, the approach may be applied to other lipids and biomolecules, in order to predict their vibrational dispersion relations, and to study the dynamics of vibrational energy transfer.

  19. Gas hydrates in the ocean environment

    USGS Publications Warehouse

    Dillon, William P.

    2002-01-01

    A GAS HYDRATE, also known as a gas clathrate, is a gas-bearing, icelike material. It occurs in abundance in marine sediments and stores immense amounts of methane, with major implications for future energy resources and global climate change. Furthermore, gas hydrate controls some of the physical properties of sedimentary deposits and thereby influences seafloor stability.

  20. 78 FR 37536 - Methane Hydrate Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Methane... meeting. SUMMARY: This notice announces a meeting of the Methane Hydrate Advisory Committee. The Federal... of the Methane Hydrate Advisory Committee is to provide advice on potential applications of...

  1. 76 FR 59667 - Methane Hydrate Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Methane... Meeting. SUMMARY: This notice announces a meeting of the Methane Hydrate Advisory Committee. Federal... of the Committee: The purpose of the Methane Hydrate Advisory Committee is to provide advice...

  2. 78 FR 26337 - Methane Hydrate Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Methane... Meeting. SUMMARY: This notice announces a meeting of the Methane Hydrate Advisory Committee. The Federal... of the Methane Hydrate Advisory Committee is to provide advice on potential applications of...

  3. Free energy of hydration of niobium oxide

    SciTech Connect

    Plodinec, M.J.

    1996-08-21

    Some of the glasses being formulated by SRTC researchers contain niobium oxide. In this report, the free energy of hydration of the oxide is calculated from the free energies of formation of the oxide, the hydroxide, and water. This value can be used in calculations of the free energy of hydration of glasses containing niobium.

  4. Production of biodiesel from mixed waste vegetable oil using an aluminium hydrogen sulphate as a heterogeneous acid catalyst.

    PubMed

    Ramachandran, Kasirajan; Sivakumar, Pandian; Suganya, Tamilarasan; Renganathan, Sahadevan

    2011-08-01

    Al(HSO(4))(3) heterogeneous acid catalyst was prepared by the sulfonation of anhydrous AlCl(3). This catalyst was employed to catalyze transesterification reaction to synthesis methyl ester when a mixed waste vegetable oil was used as feedstock. The physical and chemical properties of aluminum hydrogen sulphate catalyst were characterized by scanning electron microscopy (SEM) measurements, energy dispersive X-ray (EDAX) analysis and titration method. The maximum conversion of triglyceride was achieved as 81 wt.% with 50 min reaction time at 220°C, 16:1 molar ratio of methanol to oil and 0.5 wt.% of catalyst. The high catalytic activity and stability of this catalyst was related to its high acid site density (-OH, Brönsted acid sites), hydrophobicity that prevented the hydration of -OH group, hydrophilic functional groups (-SO(3)H) that gave improved accessibility of methanol to the triglyceride. The fuel properties of methyl ester were analyzed. The fuel properties were found to be observed within the limits of ASTM D6751.

  5. An overview of geoengineering of climate using stratospheric sulphate aerosols.

    PubMed

    Rasch, Philip J; Tilmes, Simone; Turco, Richard P; Robock, Alan; Oman, Luke; Chen, Chih-Chieh; Stenchikov, Georgiy L; Garcia, Rolando R

    2008-11-13

    We provide an overview of geoengineering by stratospheric sulphate aerosols. The state of understanding about this topic as of early 2008 is reviewed, summarizing the past 30 years of work in the area, highlighting some very recent studies using climate models, and discussing methods used to deliver sulphur species to the stratosphere. The studies reviewed here suggest that sulphate aerosols can counteract the globally averaged temperature increase associated with increasing greenhouse gases, and reduce changes to some other components of the Earth system. There are likely to be remaining regional climate changes after geoengineering, with some regions experiencing significant changes in temperature or precipitation. The aerosols also serve as surfaces for heterogeneous chemistry resulting in increased ozone depletion. The delivery of sulphur species to the stratosphere in a way that will produce particles of the right size is shown to be a complex and potentially very difficult task. Two simple delivery scenarios are explored, but similar exercises will be needed for other suggested delivery mechanisms. While the introduction of the geoengineering source of sulphate aerosol will perturb the sulphur cycle of the stratosphere signicantly, it is a small perturbation to the total (stratosphere and troposphere) sulphur cycle. The geoengineering source would thus be a small contributor to the total global source of 'acid rain' that could be compensated for through improved pollution control of anthropogenic tropospheric sources. Some areas of research remain unexplored. Although ozone may be depleted, with a consequent increase to solar ultraviolet-B (UVB) energy reaching the surface and a potential impact on health and biological populations, the aerosols will also scatter and attenuate this part of the energy spectrum, and this may compensate the UVB enhancement associated with ozone depletion. The aerosol will also change the ratio of diffuse to direct energy

  6. An overview of geoengineering of climate using stratospheric sulphate aerosols

    SciTech Connect

    Rasch, Philip J.; Tilmes, S.; Turco, Richard P.; Robock, Alan; Oman, Luke; Chen, Chih-Chieh; Stenchikov, Georgiy; Garcia, Rolando R.

    2010-01-01

    We provide an overview of geoengineering by stratospheric sulphate aerosols. The state of understanding about this topic as of early 2008 is reviewed, summarizing the past 30 years of work in the area, highlighting some very recent studies using climate models, and discussing methods used to deliver sulphur species to the stratosphere. The studies reviewed here suggest that sulphate aerosols can counteract the globally averaged temperature increase associated with increasing greenhouse gases, and reduce changes to some other components of the Earth system. There are likely to be remaining regional climate changes after geoengineering, with some regions experiencing significant changes in temperature or precipitation. The aerosols also serve as surfaces for heterogeneous chemistry resulting in increased ozone depletion. The delivery of sulphur species to the stratosphere in a way that will produce particles of the right size is shown to be a complex and potentially very difficult task. Two simple delivery scenarios are explored, but similar exercises will be needed for other suggested delivery mechanisms. While the introduction of the geoengineering source of sulphate aerosol will perturb the sulphur cycle of the stratosphere signicantly, it is a small perturbation to the total (stratosphere and troposphere) sulphur cycle. The geoengineering source would thus be a small contributor to the total global source of ‘acid rain’ that could be compensated for through improved pollution control of anthropogenic tropospheric sources. Some areas of research remain unexplored. Although ozone may be depleted, with a consequent increase to solar ultraviolet-B (UVB) energy reaching the surface and a potential impact on health and biological populations, the aerosols will also scatter and attenuate this part of the energy spectrum, and this may compensate the UVB enhancement associated with ozone depletion. The aerosol will also change the ratio of diffuse to direct energy

  7. Properties of Sarychev sulphate aerosols over the Arctic

    NASA Astrophysics Data System (ADS)

    O'Neill, N. T.; Perro, C.; Saha, A.; Lesins, G.; Duck, T. J.; Eloranta, E. W.; Nott, G. J.; Hoffman, A.; Karumudi, M. L.; Ritter, C.; Bourassa, A.; Abboud, I.; Carn, S. A.; Savastiouk, V.

    2012-02-01

    Aerosols from the Sarychev Peak volcano entered the Arctic region less than a week after the strongest SO2eruption on June 15 and 16, 2009 and had, by the first week in July, spread out over the entire Arctic region. These predominantly stratospheric aerosols were determined to be sub-micron in size and inferred to be composed of sulphates produced from the condensation of SO2gases emitted during the eruption. Average (500 nm) Sarychev-induced stratospheric optical depths (SOD) over the Polar Environmental Atmospheric Research Laboratory (PEARL) at Eureka (Nunavut, Canada) were found to be between 0.03 and 0.05 during the months of July and August, 2009. This estimate, derived from sunphotometry and integrated lidar backscatter profiles was consistent with averages derived from lidar estimates over Ny-Ålesund (Spitsbergen). The Sarychev SOD e-folding time at Eureka, deduced from lidar profiles, was found to be approximately 4 months relative to a regression start date of July 27. These profiles initially revealed the presence of multiple Sarychev plumes between the tropopause and about 17 km altitude. After about two months, the complex vertical plume structures had collapsed into fewer, more homogeneous plumes located near the tropopause. It was found that the noisy character of daytime backscatter returns induced an artifactual minimum in the temporal, pan-Arctic, CALIOP SOD response to Sarychev sulphates. A depolarization ratio discrimination criterion was used to separate the CALIOP stratospheric layer class into a low depolarization subclass which was more representative of Sarychev sulphates. Post-SAT (post Sarychev Arrival Time) retrievals of the fine mode effective radius (reff,f) and the logarithmic standard deviation for two Eureka sites and Thule (Greenland) were all close to 0.25 μm and 1.6 respectively. The stratospheric analogue to the columnar reff,f average was estimated to be reff,f(+) = 0.29 μm for Eureka data. Stratospheric, Raman lidar

  8. Isotopic fractionation of methane and ethane hydrates between gas and hydrate phases

    NASA Astrophysics Data System (ADS)

    Hachikubo, Akihiro; Kosaka, Tomoko; Kida, Masato; Krylov, Alexey; Sakagami, Hirotoshi; Minami, Hirotsugu; Takahashi, Nobuo; Shoji, Hitoshi

    2007-11-01

    Isotopic fractionation of carbon and hydrogen in methane and ethane during the formation of gas hydrates was investigated. The gas hydrate samples were experimentally prepared in a pressure cell and isotopic compositions of both residual and hydrate-bound gases were measured. δD of hydrate-bound molecules of methane and ethane hydrates was several per mil lower than that of residual gas molecules in the formation processes, while there was no difference in the case of δ 13C. These isotopic differences in δD are enough small for discussing the source types of hydrate-bound gases using the δ 13C-δD diagram of Whiticar et al. [1986]. These results may provide useful insight into the formation process of gas hydrates.

  9. Development-dependent modification of the extracellular matrix by a sulphated glycoprotein in Volvox carteri.

    PubMed

    Wenzl, S; Thym, D; Sumper, M

    1984-04-01

    We report the chemical characterization of the highly sulphated glycoprotein SSG 185 from Volvox carteri. SSG 185 is a hydroxyproline-containing, extracellular glycoprotein. The sulphate residues are clustered within the parent saccharide structure of SSG 185, since on mercaptolysis all the sulphate residues are recovered in a small saccharide fragment containing mannose, arabinose and sulphate (in a molar ratio of 112). SSG 185 is a short-lived molecule, serving as a precursor for a high mol. wt. component of the extracellular matrix. Synthesis of SSG 185 is developmentally controlled. Different SSG 185 variants, with unknown modifications in the sulphated saccharide fragment, are synthesized at different developmental stages or under the influence of the sexual inducer. These modifications remain conserved in the aggregated state of SSG 185, indicating the development-dependent modification of the extracellular matrix. PMID:16453512

  10. Effective treatment of Wilson's disease with oral zinc sulphate: two case reports.

    PubMed

    Hoogenraad, T U; Van den Hamer, C J; Van Hattum, J

    1984-08-01

    Most patients with Wilson's disease are treated with the potentially toxic cupriuretic agent penicillamine. The toxicity of zinc taken by mouth is low, and long term administration induces a negative copper balance. Two patients with severe neurological symptoms were given zinc sulphate by mouth three times daily in doses of 200 mg, later increased to 300 mg. One patient, a 21 year old man, started to receive zinc sulphate after his condition had deteriorated during treatment with cupriuretic drugs. The other, a 27 year old woman, was treated from the start with zinc sulphate. The conditions of both patients improved appreciably, and they were still receiving treatment with zinc sulphate roughly two years later. Effective depletion of body copper stores was shown by an intravenous radiocopper loading test and liver biopsy. No side effects were found. Wilson's disease may effectively be treated with zinc sulphate alone.

  11. Effect of zinc sulphate on acetic acid-induced gastric ulceration in rats.

    PubMed

    Li, K M

    1990-09-01

    The effects of zinc sulphate on gastric ulcer healing rate and mucosal mucus content of acetic acid-induced ulceration in rats have been assessed. Daily treatment with zinc sulphate progressively accelerated ulcer healing in a dose-dependent manner with a significant increase observed on day 15 after ulcer induction in rats treated with 44 and 88 mg kg-1 zinc sulphate. A significant increase in gastric mucosal adherent mucus was also observed in those animals treated with 88 mg kg-1 zinc sulphate. The results suggest that a minimum treatment period of 15 days is needed for the zinc sulphate to be effective, and that zinc ions may promote gastric ulcer healing by enhancing mucus formation to prevent acid back-diffusion into the gastric mucosa.

  12. Oral zinc sulphate as long-term treatment in Wilson's disease (hepatolenticular degeneration).

    PubMed

    Hoogenraad, T U; Koevoet, R; de Ruyter Korver, E G

    1979-01-01

    Clinical amelioration, clearance of Kayser-Fleischer rings and rising of ceruloplasmin concentration are described in a patient with the classical findings of Wilson's disease. These changes occurred during a 14-year period in which he used oral zinc sulphate (three times daily 200 mg) as the only medication to influence copper metabolism. Before starting this long-term zinc sulphate therapy he had used D-penicillamine (three times daily 300 mg) for only 6 weeks. The antagonistic action of zinc sulphate on copper resorption with amelioration of the clinical condition has been described before in this patient in 1961 by Schouwink. The patient had used at that time oral zinc sulphate for approximately 1.5 years. No changes in Kayser-Fleischer rings and ceruloplasmin levels were mentioned. Our findings suggest that oral zinc sulphate may not only prevent storage of copper in the tissues but may also contribute to the mobilization and excretion of deposits of copper.

  13. Isotope composition of sulphate in acid mine drainage as measure of bacterial oxidation

    USGS Publications Warehouse

    Taylor, B.E.; Wheeler, M.C.; Nordstrom, D.K.

    1984-01-01

    The formation of acid waters by oxidation of pyrite-bearing ore deposits, mine tailing piles, and coal measures is a complex biogeochemical process and is a serious environmental problem. We have studied the oxygen and sulphur isotope geochemistry of sulphides, sulphur, sulphate and water in the field and in experiments to identify sources of oxygen and reaction mechanisms of sulphate formation. Here we report that the oxygen isotope composition of sulphate in acid mine drainage shows a large variation due to differing proportions of atmospheric- and water-derived oxygen from both chemical and bacterially-mediated oxidation. 18O-enrichment of sulphate results from pyrite oxidation facilitated by Thiobacillus ferrooxidans in aerated environments. Oxygen isotope analysis may therefore be useful in monitoring the effectiveness of abatement programmes designed to inhibit bacterial oxidation. Sulphur isotopes show no significant fractionation between pyrite and sulphate, indicating the quantitative insignificance of intermediate oxidation states of sulphur under acid conditions. ?? 1984 Nature Publishing Group.

  14. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Donn McGuire; Steve Runyon; Richard Sigal; Bill Liddell; Thomas Williams; George Moridis

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. Hot Ice No. 1 was planned to test the Ugnu and West Sak sequences for gas hydrates and a concomitant free gas accumulation on Anadarko's 100% working interest acreage in section 30 of Township 9N, Range 8E of the Harrison Bay quadrangle of the North Slope of Alaska. The Ugnu and West Sak intervals are favorably positioned in the hydrate-stability zone over an area extending from Anadarko's acreage westward to the vicinity of the aforementioned gas-hydrate occurrences. This suggests that a large, north-to-south trending gas-hydrate accumulation may exist in that area. The presence of gas shows in the Ugnu and West Sak reservoirs in wells situated eastward and down dip of the Hot Ice location indicate that a free-gas accumulation may be trapped by gas hydrates. The Hot Ice No. 1 well was designed to core from the surface to the base of the West Sak interval using the revolutionary and new

  15. Raman tomography of natural air hydrates

    NASA Astrophysics Data System (ADS)

    Weikusat, Christian; Kipfstuhl, Sepp; Weikusat, Ilka

    2015-04-01

    Ice cores are the only climate archives incorporating paleo-atmosphere as individual gas inclusions, enabling the extraction and analysis of the contained gasses. A firm understanding of the processes involved is mandatory for a reliable interpretation of the gas records. One prominent process is the transition from air bubbles to crystalline air hydrates, which is known to influence, at least temporarily, the gas mixing ratios by diffusion and fractionation. This transition is still not understood completely and the existing theories do not explain the large diversity of observed hydrate morphologies. Raman tomographic measurements using the AWI cryo-Raman system provide 3D reconstructions of air hydrate morphologies. The results show complex growth structures that emphasize the importance of crystallography, microstructure and ice rheology for the hydrate formation process. Accurate hydrate volumes can be calculated from the 3D objects, improving the estimates of total gas contents.

  16. Hydration forces at solid and fluid biointerfaces.

    PubMed

    Shrestha, Buddha Ratna; Banquy, Xavier

    2016-03-01

    The authors review the different molecular mechanisms giving rise to the repulsive hydration force between biologically relevant surfaces such as lipid bilayers and bioceramics. As the authors will show, the hydration force manifests itself in very different and subtle ways depending on the substrates. Soft, mobile surfaces such as lipid bilayers tend to exhibit monotonic, decaying hydration force, originated from the entropic constriction of the lipid head groups. Solid surfaces, on the other hand, tend to exhibit a periodic oscillatory hydration force, originated from the surface induced polarization of water molecules. In this review, the authors will describe both subtle faces of this important interaction by first describing the early experiments performed on solid surfaces and their interpretation by recent simulation studies. Then, the authors will describe the hydration force between fluid interfaces such as bilayers and explain how experimentally researchers have unraveled the dominant role of the lipid head groups' conformation. PMID:26795057

  17. Stress proteins expression in rat kidney and liver chronically exposed to aluminium sulphate.

    PubMed

    Stacchiotti, A; Rodella, L F; Ricci, F; Rezzani, R; Lavazza, A; Bianchi, R

    2006-02-01

    Aluminium (Al) is the third most widespread metal in the environment. It is toxic for the brain, bone and haematological system but unfortunately very little data exist for other organs. Stress proteins are induced or enhanced against metal toxicity with an essential role in the recovery of organules and other cellular proteins. This immunohistochemical study was performed to analyze the distribution of three stress proteins (HSP25, HSP72, GRP75) in rat kidney and liver orally exposed to Al sulphate daily for 3 and 6 months. Al-induced alterations were further studied by histopathology (H-E, PAS, Perl's, Masson) and ultrastructural morphometry. In the kidney: HSP25 was enhanced in proximal tubules after 6 months Al-exposure when abnormal brush borders were observed; HSP72 was induced in proximal tubules only after long Al-treatment; GRP75 was raised in midcortical area sometimes within nuclei. Furthermore, lysosomal and lipofuscins densities increased in the juxtamedullary tubules after 3 months Al exposure with respect to controls. In the liver: Perl's-positive deposits and fibrosis became evident after Al treatment. HSP25 was very weak; HSP72 focal in pericentral hepatocytes at 3 months and induced also in Kupffer cells at 6 months; GRP75 diffuse in periportal hepatocytes and non parenchymal cells at 6 months. Prolonged Al exposure stimulated stress proteins strictly organ-dependently in the rat. Their distribution in kidney and liver seems related to cumulative sublethal effects induced by metal and could be a sensitive index of Al susceptibility of these organs.

  18. Massive volcanic SO(2) oxidation and sulphate aerosol deposition in Cenozoic North America.

    PubMed

    Bao, Huiming; Yu, Shaocai; Tong, Daniel Q

    2010-06-17

    Volcanic eruptions release a large amount of sulphur dioxide (SO(2)) into the atmosphere. SO(2) is oxidized to sulphate and can subsequently form sulphate aerosol, which can affect the Earth's radiation balance, biologic productivity and high-altitude ozone concentrations, as is evident from recent volcanic eruptions. SO(2) oxidation can occur via several different pathways that depend on its flux and the atmospheric conditions. An investigation into how SO(2) is oxidized to sulphate-the oxidation product preserved in the rock record-can therefore shed light on past volcanic eruptions and atmospheric conditions. Here we use sulphur and triple oxygen isotope measurements of atmospheric sulphate extracted from tuffaceous deposits to investigate the specific oxidation pathways from which the sulphate was formed. We find that seven eruption-related sulphate aerosol deposition events have occurred during the mid-Cenozoic era (34 to 7 million years ago) in the northern High Plains, North America. Two extensively sampled ash beds display a similar sulphate mixing pattern that has two distinct atmospheric secondary sulphates. A three-dimensional atmospheric sulphur chemistry and transport model study reveals that the observed, isotopically discrete sulphates in sediments can be produced only in initially alkaline cloudwater that favours an ozone-dominated SO(2) oxidation pathway in the troposphere. Our finding suggests that, in contrast to the weakly acidic conditions today, cloudwater in the northern High Plains may frequently have been alkaline during the mid-Cenozoic era. We propose that atmospheric secondary sulphate preserved in continental deposits represents an unexploited geological archive for atmospheric SO(2) oxidation chemistry linked to volcanism and atmospheric conditions in the past.

  19. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Buddy King

    2004-07-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope drilled and cored a well The HOT ICE No.1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report.

  20. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2005-03-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Oil-field engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in Arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrates agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored the HOT ICE No. 1 on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was designed, constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. Unfortunately, no gas hydrates were encountered in this well; however, a wealth of information was generated and is

  1. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Buddy King

    2004-06-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope drilled and cored a well The HOT ICE No.1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report.

  2. Overview on Hydrate Coring, Handling and Analysis

    SciTech Connect

    Jon Burger; Deepak Gupta; Patrick Jacobs; John Shillinglaw

    2003-06-30

    Gas hydrates are crystalline, ice-like compounds of gas and water molecules that are formed under certain thermodynamic conditions. Hydrate deposits occur naturally within ocean sediments just below the sea floor at temperatures and pressures existing below about 500 meters water depth. Gas hydrate is also stable in conjunction with the permafrost in the Arctic. Most marine gas hydrate is formed of microbially generated gas. It binds huge amounts of methane into the sediments. Worldwide, gas hydrate is estimated to hold about 1016 kg of organic carbon in the form of methane (Kvenvolden et al., 1993). Gas hydrate is one of the fossil fuel resources that is yet untapped, but may play a major role in meeting the energy challenge of this century. In June 2002, Westport Technology Center was requested by the Department of Energy (DOE) to prepare a ''Best Practices Manual on Gas Hydrate Coring, Handling and Analysis'' under Award No. DE-FC26-02NT41327. The scope of the task was specifically targeted for coring sediments with hydrates in Alaska, the Gulf of Mexico (GOM) and from the present Ocean Drilling Program (ODP) drillship. The specific subjects under this scope were defined in 3 stages as follows: Stage 1: Collect information on coring sediments with hydrates, core handling, core preservation, sample transportation, analysis of the core, and long term preservation. Stage 2: Provide copies of the first draft to a list of experts and stakeholders designated by DOE. Stage 3: Produce a second draft of the manual with benefit of input from external review for delivery. The manual provides an overview of existing information available in the published literature and reports on coring, analysis, preservation and transport of gas hydrates for laboratory analysis as of June 2003. The manual was delivered as draft version 3 to the DOE Project Manager for distribution in July 2003. This Final Report is provided for records purposes.

  3. Recent Insights into Cell Surface Heparan Sulphate Proteoglycans and Cancer.

    PubMed

    Couchman, John R; Multhaupt, Hinke; Sanderson, Ralph D

    2016-01-01

    A small group of cell surface receptors are proteoglycans, possessing a core protein with one or more covalently attached glycosaminoglycan chains. They are virtually ubiquitous and their chains are major sites at which protein ligands of many types interact. These proteoglycans can signal and regulate important cell processes, such as adhesion, migration, proliferation, and differentiation. Since many protein ligands, such as growth factors, morphogens, and cytokines, are also implicated in tumour progression, it is increasingly apparent that cell surface proteoglycans impact tumour cell behaviour. Here, we review some recent advances, emphasising that many tumour-related functions of proteoglycans are revealed only after their modification in processes subsequent to synthesis and export to the cell surface. These include enzymes that modify heparan sulphate structure, recycling of whole or fragmented proteoglycans into exosomes that can be paracrine effectors or biomarkers, and lateral interactions between some proteoglycans and calcium channels that impact the actin cytoskeleton. PMID:27408707

  4. Development of Stability-Indicating Methods for Cefquinome Sulphate

    PubMed Central

    Shantier, Shaza W.; Gadkariem, Elrasheed A.; Adam, Mohamed O.; Mohamed, Magdi A.

    2013-01-01

    The degradation behavior of cefquinome sulphate in alkaline medium at different temperatures was investigated using both first derivative spectrophotometric and HPLC methods. The drug degradation was found to be pH and temperature dependant. The pH-rate profile indicated a first order dependence of Kobs on [OH-] at pHs ranging between 9 and 11. Arrhenius plot obtained at pH 10 was linear between 65° and 100°C. The estimated activation energy of the hydrolysis was found to be 21.1 kcal mol-1. Stability-indicating thin-layer chromatographic method for the separation of the drug and its alkaline hydrolysis product has been developed. PMID:24170991

  5. Giant barocaloric effects at low pressure in ferrielectric ammonium sulphate.

    PubMed

    Lloveras, P; Stern-Taulats, E; Barrio, M; Tamarit, J-Ll; Crossley, S; Li, W; Pomjakushin, V; Planes, A; Mañosa, Ll; Mathur, N D; Moya, X

    2015-11-26

    Caloric effects are currently under intense study due to the prospect of environment-friendly cooling applications. Most of the research is centred on large magnetocaloric effects and large electrocaloric effects, but the former require large magnetic fields that are challenging to generate economically and the latter require large electric fields that can only be applied without breakdown in thin samples. Here we use small changes in hydrostatic pressure to drive giant inverse barocaloric effects near the ferrielectric phase transition in ammonium sulphate. We find barocaloric effects and strengths that exceed those previously observed near magnetostructural phase transitions in magnetic materials. Our findings should therefore inspire the discovery of giant barocaloric effects in a wide range of unexplored ferroelectric materials, ultimately leading to barocaloric cooling devices.

  6. Multifunctional chondroitin sulphate for cartilage tissue-biomaterial integration

    NASA Astrophysics Data System (ADS)

    Wang, Dong-An; Varghese, Shyni; Sharma, Blanka; Strehin, Iossif; Fermanian, Sara; Gorham, Justin; Fairbrother, D. Howard; Cascio, Brett; Elisseeff, Jennifer H.

    2007-05-01

    A biologically active, high-strength tissue adhesive is needed for numerous medical applications in tissue engineering and regenerative medicine. Integration of biomaterials or implants with surrounding native tissue is crucial for both immediate functionality and long-term performance of the tissue. Here, we use the biopolymer chondroitin sulphate (CS), one of the major components of cartilage extracellular matrix, to develop a novel bioadhesive that is readily applied and acts quickly. CS was chemically functionalized with methacrylate and aldehyde groups on the polysaccharide backbone to chemically bridge biomaterials and tissue proteins via a twofold covalent link. Three-dimensional hydrogels (with and without cells) bonded to articular cartilage defects. In in vitro and in vivo functional studies this approach led to mechanical stability of the hydrogel and tissue repair in cartilage defects.

  7. Chalcopyrite concentrate leaching with biologically produced ferric sulphate.

    PubMed

    Kinnunen, P H-M; Heimala, S; Riekkola-Vanhanen, M-L; Puhakka, J A

    2006-09-01

    Biological ferric iron production was combined with ferric sulphate leaching of chalcopyrite concentrate and the effects of pH, Fe3+, temperature and solids concentration on the leaching were studied. The copper leaching rates were similar at pH of 1.0-1.8 and in the presence of 7-90 g L-1 Fe3+ despite massive iron precipitation with 90 g L-1 Fe3+. Increase of the leaching temperature from 50 degrees C to 86 degrees C and solids concentration from 1% to 10% increased the copper leaching rate. Increase in solids concentration from 1% to 10% decreased the copper yields from 80% to 40%. Stepwise addition of ferric iron did not improve the copper yields. CuFeS2, Ag and Cu1.96S potentials indicated the formation of a passivating layer, which consisted of jarosite and sulphur precipitates and which was responsible for the decreased leaching rates. PMID:16154742

  8. Giant barocaloric effects at low pressure in ferrielectric ammonium sulphate.

    PubMed

    Lloveras, P; Stern-Taulats, E; Barrio, M; Tamarit, J-Ll; Crossley, S; Li, W; Pomjakushin, V; Planes, A; Mañosa, Ll; Mathur, N D; Moya, X

    2015-01-01

    Caloric effects are currently under intense study due to the prospect of environment-friendly cooling applications. Most of the research is centred on large magnetocaloric effects and large electrocaloric effects, but the former require large magnetic fields that are challenging to generate economically and the latter require large electric fields that can only be applied without breakdown in thin samples. Here we use small changes in hydrostatic pressure to drive giant inverse barocaloric effects near the ferrielectric phase transition in ammonium sulphate. We find barocaloric effects and strengths that exceed those previously observed near magnetostructural phase transitions in magnetic materials. Our findings should therefore inspire the discovery of giant barocaloric effects in a wide range of unexplored ferroelectric materials, ultimately leading to barocaloric cooling devices. PMID:26607989

  9. Giant barocaloric effects at low pressure in ferrielectric ammonium sulphate

    PubMed Central

    Lloveras, P.; Stern-Taulats, E.; Barrio, M.; Tamarit, J.-Ll.; Crossley, S.; Li, W.; Pomjakushin, V.; Planes, A.; Mañosa, Ll.; Mathur, N. D.; Moya, X.

    2015-01-01

    Caloric effects are currently under intense study due to the prospect of environment-friendly cooling applications. Most of the research is centred on large magnetocaloric effects and large electrocaloric effects, but the former require large magnetic fields that are challenging to generate economically and the latter require large electric fields that can only be applied without breakdown in thin samples. Here we use small changes in hydrostatic pressure to drive giant inverse barocaloric effects near the ferrielectric phase transition in ammonium sulphate. We find barocaloric effects and strengths that exceed those previously observed near magnetostructural phase transitions in magnetic materials. Our findings should therefore inspire the discovery of giant barocaloric effects in a wide range of unexplored ferroelectric materials, ultimately leading to barocaloric cooling devices. PMID:26607989

  10. Recent Insights into Cell Surface Heparan Sulphate Proteoglycans and Cancer

    PubMed Central

    Couchman, John R; Multhaupt, Hinke; Sanderson, Ralph D.

    2016-01-01

    A small group of cell surface receptors are proteoglycans, possessing a core protein with one or more covalently attached glycosaminoglycan chains. They are virtually ubiquitous and their chains are major sites at which protein ligands of many types interact. These proteoglycans can signal and regulate important cell processes, such as adhesion, migration, proliferation, and differentiation. Since many protein ligands, such as growth factors, morphogens, and cytokines, are also implicated in tumour progression, it is increasingly apparent that cell surface proteoglycans impact tumour cell behaviour. Here, we review some recent advances, emphasising that many tumour-related functions of proteoglycans are revealed only after their modification in processes subsequent to synthesis and export to the cell surface. These include enzymes that modify heparan sulphate structure, recycling of whole or fragmented proteoglycans into exosomes that can be paracrine effectors or biomarkers, and lateral interactions between some proteoglycans and calcium channels that impact the actin cytoskeleton. PMID:27408707

  11. Giant barocaloric effects at low pressure in ferrielectric ammonium sulphate

    NASA Astrophysics Data System (ADS)

    Lloveras, P.; Stern-Taulats, E.; Barrio, M.; Tamarit, J.-Ll.; Crossley, S.; Li, W.; Pomjakushin, V.; Planes, A.; Mañosa, Ll.; Mathur, N. D.; Moya, X.

    2015-11-01

    Caloric effects are currently under intense study due to the prospect of environment-friendly cooling applications. Most of the research is centred on large magnetocaloric effects and large electrocaloric effects, but the former require large magnetic fields that are challenging to generate economically and the latter require large electric fields that can only be applied without breakdown in thin samples. Here we use small changes in hydrostatic pressure to drive giant inverse barocaloric effects near the ferrielectric phase transition in ammonium sulphate. We find barocaloric effects and strengths that exceed those previously observed near magnetostructural phase transitions in magnetic materials. Our findings should therefore inspire the discovery of giant barocaloric effects in a wide range of unexplored ferroelectric materials, ultimately leading to barocaloric cooling devices.

  12. Bioactivity and Applications of Sulphated Polysaccharides from Marine Microalgae

    PubMed Central

    de Jesus Raposo, Maria Filomena; de Morais, Rui Manuel Santos Costa; de Morais, Alcina Maria Miranda Bernardo

    2013-01-01

    Marine microalgae have been used for a long time as food for humans, such as Arthrospira (formerly, Spirulina), and for animals in aquaculture. The biomass of these microalgae and the compounds they produce have been shown to possess several biological applications with numerous health benefits. The present review puts up-to-date the research on the biological activities and applications of polysaccharides, active biocompounds synthesized by marine unicellular algae, which are, most of the times, released into the surrounding medium (exo- or extracellular polysaccharides, EPS). It goes through the most studied activities of sulphated polysaccharides (sPS) or their derivatives, but also highlights lesser known applications as hypolipidaemic or hypoglycaemic, or as biolubricant agents and drag-reducers. Therefore, the great potentials of sPS from marine microalgae to be used as nutraceuticals, therapeutic agents, cosmetics, or in other areas, such as engineering, are approached in this review. PMID:23344113

  13. Liposomes of terbutaline sulphate: in vitro and in vivo studies.

    PubMed

    Joshi, M R; Misra, A N

    1999-09-01

    In vitro studies were conducted to understand the comparative drug diffusion pattern, across artificial membrane, of the drug and of the prepared liposomes of different liposomal membrane composition. In vivo studies were carried out to determine the extent and time-course of pulmonary tissue uptake of administered liposomes containing terbutaline sulphate(TER) on rat lungs. In vitro studies revealed that the drug released from the prepared liposomes obeys Higuchi's diffusion controlled model. Different loading doses and release patterns of drug from the liposomes can be obtained by altering the PC:CHOL ratio and incorporation of cholesterol was found to reduce permeability of the membrane. Similarly drug absorption in vivo in rat's lung following intratracheal instillation, prolonged over 12 hr by liposomal entrapment of TER. The findings of present investigation indicated that liposomally encapsulated TER can be used for pulmonary delivery for maximizing the therapeutic efficacy and reducing undesirable side effects. PMID:10687283

  14. Modelling the growth of triglycine sulphate crystals in Spacelab 3

    NASA Technical Reports Server (NTRS)

    Yoo, Hak-Do; Wilcox, William R.; Lal, Ravindra; Trolinger, James D.

    1988-01-01

    Two triglycine sulphate crystals were grown from an aqueous solution in Spacelab 3 aboard a Space Shuttle. Using a diffusion coefficient of 0.00002 sq cm/s, a computerized simulation gave reasonable agreement between experimental and theoretical crystal sizes and interferometric lines in the solution near the growing crystal. This diffusion coefficient is larger than most measured values, possibly due to fluctuating accelerations on the order of .001 g (Earth's gravity). The average acceleration was estimated to be less than .000001 g. At this level, buoyancy driven convection is predicted to add approx. 20 percent to the steady state growth rate. Only very slight distortion of the interferometric lines was observed at the end of a 33 hr run. It is suggested that the time to reach steady state convective transport may be inversely proportional to g at low g, so that the full effect of convection was not realized in these experiments.

  15. Sulphate Geoengineering in the UT/LS: Some Relevant Processes

    NASA Astrophysics Data System (ADS)

    Tuck, A. F.; Donaldson, D. J.; Hitchman, M. H.; Richard, E. C.; Tervahattu, H.; Vaida, V.; Wilson, J. C.

    2008-12-01

    We consider the potential effects of meteorological dynamics, the physics and chemistry of aerosols and the photodissociation of sulphuric acid upon the posited maintenance of a 'parasol' of geoengineered sulphate aerosol in the lower stratosphere. Specific observational and experimental results include the spread of tungsten-185 from the Hardtack series of nuclear weapon tests in 1958, satellite observations of the spread of volcanic eruptions, tracer and water profiles in the tropical UT/LS, the organic coating of surfactants on aerosols, the observed distributions of aerosols and the overtone driven photodissociation of sulphuric acid in the stratosphere. A few implications for the logistics of any possible future geoengineering injection are considered briefly. The uncertainties arising from the analysis subtract significantly from the predictability of any supposed amelioration of the effects of global warming from continued increases in carbon dioxide from fossil fuel combustion.

  16. Intravesical chondroitin sulphate for interstitial cystitis/painful bladder syndrome

    PubMed Central

    Hennessy, DB; Curry, D; Cartwright, C; Downey, P; Pahuja, A

    2015-01-01

    Introduction Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic inflammatory condition of the bladder. Bladder instillation is one avenue of treatment but evidence for its effectiveness is limited. Chondroitin sulphate solution 2.0% (Urocyst) is a glycosaminoglycan (GAG) replenishment therapy instilled for patients with IC/PBS. We assessed its effectiveness for treating IC/PBS in Northern Ireland. Methods Patients with IC/PBS were assessed with the O'Leary-Sant interstitial cystitis index score and global response assessment questionnaire prior to commencing treatment. Assessment with these questionnaires was performed after 6 treatments (10 weeks) and again after 10 treatments (24 weeks). Assessment end points were pain, urgency, symptom score and problem score. Results Data was collected on 10 patients, 9 female and 1 male. 6 patients had failed RIMSO-50 dimethyl sulphoxide (DMSO) 50% treatment prior. At baseline the mean pain score was 6.6, urgency score 7.00, symptom score 13.5 and problem score 12.5. After 24 weeks the mean pain score fell to 2.0, urgency score to 1.80, symptom score to 6.89 and problem score to 5.67. At 10 weeks the global response to treatment was 100%. Nocturia was the first symptom to improve with urgency and pain following. No side effects were noted during instillation and all patients tolerated the treatments. Conclusion IC/PBS is a difficult disease to treat. It requires a multimodal approach. We found that intravesical chondroitin sulphate reduced pain, urgency and O'Leary-Sant symptom and problem scores in patients with IC/PBS. All patients tolerated the treatment and no side effects were reported. PMID:26668417

  17. Clathrate hydrate tuning for technological purposes

    NASA Astrophysics Data System (ADS)

    di Profio, Pietro; Germani, Raimondo; Savelli, Gianfranco

    2010-05-01

    Gas hydrates are being increasingly considered as convenient media for gas storage and transportation as the knowledge of their properties increases, in particular as relates to methane and hydrogen. Clathrate hydrates may also represent a feasible sequestration technology for carbon dioxide, due to a well defined P/T range of stability, and several research programs are addressing this possibility. Though the understanding of the molecular structure and supramolecular interactions which are responsible of most properties of hydrates have been elucitated in recent years, the underlying theoretical physico-chemical framework is still poor, especially as relates to the role of "conditioners" (inhibitors and promoters) from the molecular/supramolecular point of view. In the present communication we show some results from our research approach which is mainly focused on the supramolecular properties of clathrate hydrate systems - and their conditioners - as a way to get access to a controlled modulation of the formation, dissociation and stabilization of gas hydrates. In particular, this communication will deal with: (a) a novel, compact apparatus for studying the main parameters of formation and dissociation of gas hydrates in a one-pot experiment, which can be easily and rapidly carried out on board of a drilling ship;[1] (b) the effects of amphiphile molecules (surfactants) as inhibitors or promoters of gas hydrate formation;[2] (c) a novel nanotechnology for a reliable and quick production of hydrogen hydrates, and its application to fuel cells;[3,4] and (d) the development of a clathrate hydrate tecnology for the sequestration and geological storage of man-made CO2, possibly with concomitant recovery of natural gas from NG hydrate fields. Furthermore, the feasibility of catalyzing the reduction of carbon dioxide to energy-rich species by hydrates is being investigated. [1] Di Profio, P., Germani, R., Savelli, G., International Patent Application PCT/IT2006

  18. Methane Recovery from Hydrate-bearing Sediments

    SciTech Connect

    J. Carlos Santamarina; Costas Tsouris

    2011-04-30

    Gas hydrates are crystalline compounds made of gas and water molecules. Methane hydrates are found in marine sediments and permafrost regions; extensive amounts of methane are trapped in the form of hydrates. Methane hydrate can be an energy resource, contribute to global warming, or cause seafloor instability. This study placed emphasis on gas recovery from hydrate bearing sediments and related phenomena. The unique behavior of hydrate-bearing sediments required the development of special research tools, including new numerical algorithms (tube- and pore-network models) and experimental devices (high pressure chambers and micromodels). Therefore, the research methodology combined experimental studies, particle-scale numerical simulations, and macro-scale analyses of coupled processes. Research conducted as part of this project started with hydrate formation in sediment pores and extended to production methods and emergent phenomena. In particular, the scope of the work addressed: (1) hydrate formation and growth in pores, the assessment of formation rate, tensile/adhesive strength and their impact on sediment-scale properties, including volume change during hydrate formation and dissociation; (2) the effect of physical properties such as gas solubility, salinity, pore size, and mixed gas conditions on hydrate formation and dissociation, and it implications such as oscillatory transient hydrate formation, dissolution within the hydrate stability field, initial hydrate lens formation, and phase boundary changes in real field situations; (3) fluid conductivity in relation to pore size distribution and spatial correlation and the emergence of phenomena such as flow focusing; (4) mixed fluid flow, with special emphasis on differences between invading gas and nucleating gas, implications on relative gas conductivity for reservoir simulations, and gas recovery efficiency; (5) identification of advantages and limitations in different gas production strategies with

  19. Gas Hydrate Storage of Natural Gas

    SciTech Connect

    Rudy Rogers; John Etheridge

    2006-03-31

    Environmental and economic benefits could accrue from a safe, above-ground, natural-gas storage process allowing electric power plants to utilize natural gas for peak load demands; numerous other applications of a gas storage process exist. A laboratory study conducted in 1999 to determine the feasibility of a gas-hydrates storage process looked promising. The subsequent scale-up of the process was designed to preserve important features of the laboratory apparatus: (1) symmetry of hydrate accumulation, (2) favorable surface area to volume ratio, (3) heat exchanger surfaces serving as hydrate adsorption surfaces, (4) refrigeration system to remove heat liberated from bulk hydrate formation, (5) rapid hydrate formation in a non-stirred system, (6) hydrate self-packing, and (7) heat-exchanger/adsorption plates serving dual purposes to add or extract energy for hydrate formation or decomposition. The hydrate formation/storage/decomposition Proof-of-Concept (POC) pressure vessel and supporting equipment were designed, constructed, and tested. This final report details the design of the scaled POC gas-hydrate storage process, some comments on its fabrication and installation, checkout of the equipment, procedures for conducting the experimental tests, and the test results. The design, construction, and installation of the equipment were on budget target, as was the tests that were subsequently conducted. The budget proposed was met. The primary goal of storing 5000-scf of natural gas in the gas hydrates was exceeded in the final test, as 5289-scf of gas storage was achieved in 54.33 hours. After this 54.33-hour period, as pressure in the formation vessel declined, additional gas went into the hydrates until equilibrium pressure/temperature was reached, so that ultimately more than the 5289-scf storage was achieved. The time required to store the 5000-scf (48.1 hours of operating time) was longer than designed. The lower gas hydrate formation rate is attributed to a

  20. Diffusion of CO2 During Hydrate Formation and Dissolution

    SciTech Connect

    Franklin M. Orr, Jr.

    2002-08-20

    Experiments were performed to measure the rate of diffusion of CO2 through hydrate films. Hydrate films were created in a capillary tube, and the growth of the hydrate film was measured. Difficulties were encountered in creating hydrate repeatedly, and some non-uniform growth of the films was observed. Sufficient observations were obtained to demonstrate that hydrate growth occurs preferentially on the hydrate/water side of the interface, rather than at the hydrate/CO2 interface. Diffusion coefficients were estimated from observations of the rate of growth of the hydrate film along with estimates of the solubility of CO2 in water and of the concentration gradient across the hydrate layer. The experimental observations indicate that hydrate formation occurs much more rapidly at the hydrate water interface than at the hydrate/CO2 interface. Any growth of hydrate at the CO2/hydrate interface was too slow to be observed at the time scale of the experiments. That observation is consistent with the idea that CO2 can move more easily through the hydrate, presumably by hopping between hydrate cages, than water can move through the hydrate, presumably by lattice hopping. Estimated diffusion coefficients were in the range 1-3E-06 cm2/sec. Those values are about an order of magnitude lower than the diffusion coefficient for CO2 in liquid water, but four orders of magnitude larger than the value for diffusion of CO2 in a solid. The rate of diffusion through the hydrate controls both the creation of new hydrate at the hydrate/water interface and the rate at which CO2 dissolves in the liquid water and diffuses away from the hydrate layer. Formation of a hydrate layer reduces the rate at which CO2 dissolves in liquid water.

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

    USGS Publications Warehouse

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

    2013-01-01

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

  2. Detection and Production of Methane Hydrate

    SciTech Connect

    George Hirasaki; Walter Chapman; Gerald Dickens; Colin Zelt; Brandon Dugan; Kishore Mohanty; Priyank Jaiswal

    2011-12-31

    This project seeks to understand regional differences in gas hydrate systems from the perspective of as an energy resource, geohazard, and long-term climate influence. Specifically, the effort will: (1) collect data and conceptual models that targets causes of gas hydrate variance, (2) construct numerical models that explain and predict regional-scale gas hydrate differences in 2-dimensions with minimal 'free parameters', (3) simulate hydrocarbon production from various gas hydrate systems to establish promising resource characteristics, (4) perturb different gas hydrate systems to assess potential impacts of hot fluids on seafloor stability and well stability, and (5) develop geophysical approaches that enable remote quantification of gas hydrate heterogeneities so that they can be characterized with minimal costly drilling. Our integrated program takes advantage of the fact that we have a close working team comprised of experts in distinct disciplines. The expected outcomes of this project are improved exploration and production technology for production of natural gas from methane hydrates and improved safety through understanding of seafloor and well bore stability in the presence of hydrates. The scope of this project was to more fully characterize, understand, and appreciate fundamental differences in the amount and distribution of gas hydrate and how this would affect the production potential of a hydrate accumulation in the marine environment. The effort combines existing information from locations in the ocean that are dominated by low permeability sediments with small amounts of high permeability sediments, one permafrost location where extensive hydrates exist in reservoir quality rocks and other locations deemed by mutual agreement of DOE and Rice to be appropriate. The initial ocean locations were Blake Ridge, Hydrate Ridge, Peru Margin and GOM. The permafrost location was Mallik. Although the ultimate goal of the project was to understand processes

  3. Gas Hydrates Research Programs: An International Review

    SciTech Connect

    Jorge Gabitto; Maria Barrufet

    2009-12-09

    Gas hydrates sediments have the potential of providing a huge amount of natural gas for human use. Hydrate sediments have been found in many different regions where the required temperature and pressure conditions have been satisfied. Resource exploitation is related to the safe dissociation of the gas hydrate sediments. Basic depressurization techniques and thermal stimulation processes have been tried in pilot efforts to exploit the resource. There is a growing interest in gas hydrates all over the world due to the inevitable decline of oil and gas reserves. Many different countries are interested in this valuable resource. Unsurprisingly, developed countries with limited energy resources have taken the lead in worldwide gas hydrates research and exploration. The goal of this research project is to collect information in order to record and evaluate the relative strengths and goals of the different gas hydrates programs throughout the world. A thorough literature search about gas hydrates research activities has been conducted. The main participants in the research effort have been identified and summaries of their past and present activities reported. An evaluation section discussing present and future research activities has also been included.

  4. Electrical properties of methane hydrate + sediment mixtures

    USGS Publications Warehouse

    Du Frane, Wyatt L.; Stern, Laura A.; Weitemeyer, Karen A.; Constable, Steven; Roberts, Jeffery J.

    2011-01-01

    As part of our DOE-funded proposal to characterize gas hydrate in the Gulf of Mexico using marine electromagnetic methods, a collaboration between SIO, LLNL, and USGS with the goal of measuring the electrical properties of lab-created methane (CH4) hydrate and sediment mixtures was formed. We examined samples with known characteristics to better relate electrical properties measured in the field to specific gas hydrate concentration and distribution patterns. Here we discuss first-ever electrical conductivity (σ) measurements on unmixed CH4 hydrate (Du Frane et al., 2011): 6 x 10-5 S/m at 5 °C, which is ~5 orders of magnitude lower than seawater. This difference allows electromagnetic (EM) techniques to distinguish highly resistive gas hydrate deposits from conductive water saturated sediments in EM field surveys. More recently, we performed measurements on CH4 hydrate mixed with sediment and we also discuss those initial findings here. Our results on samples free of liquid water are important for predicting conductivity of sediments with pores highly saturated with gas hydrate, and are an essential starting point for comprehensive mixing models.

  5. Prospecting for marine gas hydrate resources

    USGS Publications Warehouse

    Boswell, Ray; Shipp, Craig; Reichel, Thomas; Shelander, Dianna; Saeki, Tetsuo; Frye, Matthew; Shedd, William; Collett, Timothy S.; McConnell, Daniel R.

    2016-01-01

    As gas hydrate energy assessment matures worldwide, emphasis has evolved away from confirmation of the mere presence of gas hydrate to the more complex issue of prospecting for those specific accumulations that are viable resource targets. Gas hydrate exploration now integrates the unique pressure and temperature preconditions for gas hydrate occurrence with those concepts and practices that are the basis for conventional oil and gas exploration. We have aimed to assimilate the lessons learned to date in global gas hydrate exploration to outline a generalized prospecting approach as follows: (1) use existing well and geophysical data to delineate the gas hydrate stability zone (GHSZ), (2) identify and evaluate potential direct indications of hydrate occurrence through evaluation of interval of elevated acoustic velocity and/or seismic events of prospective amplitude and polarity, (3) mitigate geologic risk via regional seismic and stratigraphic facies analysis as well as seismic mapping of amplitude distribution along prospective horizons, and (4) mitigate further prospect risk through assessment of the evidence of gas presence and migration into the GHSZ. Although a wide range of occurrence types might ultimately become viable energy supply options, this approach, which has been tested in only a small number of locations worldwide, has directed prospect evaluation toward those sand-hosted, high-saturation occurrences that were presently considered to have the greatest future commercial potential.

  6. Ab Initio Studies of Calcium Carbonate Hydration.

    PubMed

    Lopez-Berganza, Josue A; Diao, Yijue; Pamidighantam, Sudhakar; Espinosa-Marzal, Rosa M

    2015-11-25

    Ab initio simulations of large hydrated calcium carbonate clusters are challenging due to the existence of multiple local energy minima. Extensive conformational searches around hydrated calcium carbonate clusters (CaCO3·nH2O for n = 1-18) were performed to find low-energy hydration structures using an efficient combination of Monte Carlo searches, density-functional tight binding (DFTB+) method, and density-functional theory (DFT) at the B3LYP level, or Møller-Plesset perturbation theory at the MP2 level. This multilevel optimization yields several low-energy structures for hydrated calcium carbonate. Structural and energetics analysis of the hydration of these clusters revealed a first hydration shell composed of 12 water molecules. Bond-length and charge densities were also determined for different cluster sizes. The solvation of calcium carbonate in bulk water was investigated by placing the explicitly solvated CaCO3·nH2O clusters in a polarizable continuum model (PCM). The findings of this study provide new insights into the energetics and structure of hydrated calcium carbonate and contribute to the understanding of mechanisms where calcium carbonate formation or dissolution is of relevance.

  7. The thermodynamic properties of hydrated -Al2O3 nanoparticles

    SciTech Connect

    Spencer, Elinor; Huang, Baiyu; Parker, Stewart F.; Kolesnikov, Alexander I; Ross, Dr. Nancy; Woodfield, Brian

    2013-01-01

    In this paper we report a combined calorimetric and inelastic neutron scattering (INS) study of hydrated -Al2O3 ( -alumina) nanoparticles. These complementary techniques have enabled a comprehensive evaluation of the thermodynamic properties of this technological and industrially important metal oxide to be achieved. The isobaric heat capacity (Cp) data presented herein provide further critical insights into the much-debated chemical composition of -alumina nanoparticles. Furthermore, the isochoric heat capacity (Cv) of the surface water, which is so essential to the stability of all metal-oxides at the nanoscale, has been extracted from the high-resolution INS data and differs significantly from that of ice Ih due to the dominating influence of strong surface-water interactions. This study also encompassed the analysis of four -alumina samples with differing pore diameters [4.5 (1), 13.8 (2), 17.9 (3), and 27.2 nm (4)], and the results obtained allow us to unambiguously conclude that the water content and pore size have no influence on the thermodynamic behaviour of hydrated -alumina nanoparticles.

  8. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Buddy King

    2003-12-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the US have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the second year of a three-year endeavor being sponsored by maurer Technology, noble, and Anadarko Petroleum, in partnership with the DOE. The purpose of the project is to build on previous and ongoing R and D in the area of onshore hydrate deposition. They plan to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. They also plan to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope is to drill and core a well on Anadarko leases in FY 2003 and 2004. They are also using an on-site core analysis laboratory to determine some of the physical characteristics of the hydrates and surrounding rock. The well is being drilled from a new Anadarko Arctic Platform that will have minimal footprint and environmental impact. They hope to correlate geology, geophysics, logs, and drilling and production data to allow reservoir models to be calibrated. Ultimately, the goal is to form an objective technical and economic evaluation of reservoir potential in Alaska.

  9. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Buddy King

    2004-03-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the second year of a three-year endeavor being sponsored by Maurer Technology, Noble, and Anadarko Petroleum, in partnership with the DOE. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition. We plan to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. We also plan to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope is to drill and core a well on Anadarko leases in FY 2003 and 2004. We are also using an on-site core analysis laboratory to determine some of the physical characteristics of the hydrates and surrounding rock. The well is being drilled from a new Anadarko Arctic Platform that will have minimal footprint and environmental impact. We hope to correlate geology, geophysics, logs, and drilling and production data to allow reservoir models to be calibrated. Ultimately, our goal is to form an objective technical and economic evaluation of reservoir potential in Alaska.

  10. Sulphation of acetaminophen by the human cytosolic sulfotransferases: a systematic analysis.

    PubMed

    Yamamoto, Akihiro; Liu, Ming-Yih; Kurogi, Katsuhisa; Sakakibara, Yoichi; Saeki, Yuichi; Suiko, Masahito; Liu, Ming-Cheh

    2015-12-01

    Sulphation is known to be critically involved in the metabolism of acetaminophen in vivo. This study aimed to systematically identify the major human cytosolic sulfotransferase (SULT) enzyme(s) responsible for the sulphation of acetaminophen. A systematic analysis showed that three of the twelve human SULTs, SULT1A1, SULT1A3 and SULT1C4, displayed the strongest sulphating activity towards acetaminophen. The pH dependence of the sulphation of acetaminophen by each of these three SULTs was examined. Kinetic parameters of these three SULTs in catalysing acetaminophen sulphation were determined. Moreover, sulphation of acetaminophen was shown to occur in HepG2 human hepatoma cells and Caco-2 human intestinal epithelial cells under the metabolic setting. Of the four human organ samples tested, liver and intestine cytosols displayed considerably higher acetaminophen-sulphating activity than those of lung and kidney. Collectively, these results provided useful information concerning the biochemical basis underlying the metabolism of acetaminophen in vivo previously reported.

  11. Nanocrosses of lead sulphate as the negative active material of lead acid batteries

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Gao, Pengran; Bu, Xianfu; Kuang, Guizhi; Liu, Wei; Lei, Lixu

    2014-10-01

    Lead sulphate transforms into PbO2 and Pb in the positive and negative electrodes, respectively, when a lead acid battery is charged, thus, it is an active material. It is also generally acknowledged that sulphation results in the failure of lead acid batteries; therefore, it is very interesting to find out how to make lead sulphate more electrochemically active. Here, we demonstrate that nanocrystalline lead sulphate can be used as excellent negative active material in lead acid batteries. The lead sulphate nanocrystals, which are prepared by a facile chemical precipitation of aqueous lead acetate and sodium sulphate in a few minutes, look like crosses with diameter of each arm being 100 nm to 3 μm. The electrode is effectively formed in much shorter time than traditional technique, yet it discharges a capacity of 103 mA h g-1 at the current density of 120 mA g-1, which is 24% higher than that discharged by the electrode made from leady oxide under the same condition. During 100% DOD cycles, more than 80% of that capacity remains in 550 cycles. These results show that lead sulphate can be a nice negative active material in lead acid batteries.

  12. Tapping methane hydrates for unconventional natural gas

    USGS Publications Warehouse

    Ruppel, Carolyn

    2007-01-01

    Methane hydrate is an icelike form of concentrated methane and water found in the sediments of permafrost regions and marine continental margins at depths far shallower than conventional oil and gas. Despite their relative accessibility and widespread occurrence, methane hydrates have never been tapped to meet increasing global energy demands. With rising natural gas prices, production from these unconventional gas deposits is becoming economically viable, particularly in permafrost areas already being exploited for conventional oil and gas. This article provides an overview of gas hydrate occurrence, resource assessment, exploration, production technologies, renewability, and future challenges.

  13. Clathrate hydrates in cometary nuclei and porosity

    NASA Technical Reports Server (NTRS)

    Smoluchowski, R.

    1988-01-01

    Possible mechanisms of formation and decomposition of CO2-clathrate hydrate in cometary nuclei are discussed. As far as it is known, this is the only clathrate hydrate which is unstable at low temperatures. Calculation shows that, in accord with other evidence, neither volume nor grain boundary diffusion in the clathrate lattice can be responsible for the rate of these reactions and that a surface mechanism with the attendant sensitivity to pressure must play a crucial role. Density changes accompanying CO2-clathrate decomposition and formation can lead to microporosity and enhanced brittleness or even to fracture of cometary nuclei at low temperatures. Other clathrate hydrates and mixed clathrates are also discussed.

  14. Carbon dioxide hydrate and floods on Mars

    NASA Technical Reports Server (NTRS)

    Milton, D. J.

    1974-01-01

    Ground ice on Mars probably consists largely of carbon dioxide hydrate. This hydrate dissociates upon release of pressure at temperatures between 0 and 10 C. The heat capacity of the ground would be sufficient to produce up to 4% (by volume) of water at a rate equal to that at which it can be drained away. Catastrophic dissociation of carbon dioxide hydrate during some past epoch when the near-surface temperature was in this range would have produced chaotic terrain and flood channels.

  15. Three-dimensional distribution of gas hydrate beneath southern Hydrate Ridge: Constraints from ODP Leg 204

    USGS Publications Warehouse

    Trehu, A.M.; Long, P.E.; Torres, M.E.; Bohrmann, G.; Rack, F.R.; Collett, T.S.; Goldberg, D.S.; Milkov, A.V.; Riedel, M.; Schultheiss, P.; Bangs, N.L.; Barr, S.R.; Borowski, W.S.; Claypool, G.E.; Delwiche, M.E.; Dickens, G.R.; Gracia, E.; Guerin, G.; Holland, M.; Johnson, J.E.; Lee, Y.-J.; Liu, C.-S.; Su, X.; Teichert, B.; Tomaru, H.; Vanneste, M.; Watanabe, M. E.; Weinberger, J.L.

    2004-01-01

    Large uncertainties about the energy resource potential and role in global climate change of gas hydrates result from uncertainty about how much hydrate is contained in marine sediments. During Leg 204 of the Ocean Drilling Program (ODP) to the accretionary complex of the Cascadia subduction zone, we sampled the gas hydrate stability zone (GHSZ) from the seafloor to its base in contrasting geological settings defined by a 3D seismic survey. By integrating results from different methods, including several new techniques developed for Leg 204, we overcome the problem of spatial under-sampling inherent in robust methods traditionally used for estimating the hydrate content of cores and obtain a high-resolution, quantitative estimate of the total amount and spatial variability of gas hydrate in this structural system. We conclude that high gas hydrate content (30-40% of pore space or 20-26% of total volume) is restricted to the upper tens of meters below the seafloor near the summit of the structure, where vigorous fluid venting occurs. Elsewhere, the average gas hydrate content of the sediments in the gas hydrate stability zone is generally <2% of the pore space, although this estimate may increase by a factor of 2 when patchy zones of locally higher gas hydrate content are included in the calculation. These patchy zones are structurally and stratigraphically controlled, contain up to 20% hydrate in the pore space when averaged over zones ???10 m thick, and may occur in up to ???20% of the region imaged by 3D seismic data. This heterogeneous gas hydrate distribution is an important constraint on models of gas hydrate formation in marine sediments and the response of the sediments to tectonic and environmental change. ?? 2004 Published by Elsevier B.V.

  16. Methane hydrate formation in partially water-saturated Ottawa sand

    USGS Publications Warehouse

    Waite, W.F.; Winters, W.J.; Mason, D.H.

    2004-01-01

    Bulk properties of gas hydrate-bearing sediment strongly depend on whether hydrate forms primarily in the pore fluid, becomes a load-bearing member of the sediment matrix, or cements sediment grains. Our compressional wave speed measurements through partially water-saturated, methane hydrate-bearing Ottawa sands suggest hydrate surrounds and cements sediment grains. The three Ottawa sand packs tested in the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) contain 38(1)% porosity, initially with distilled water saturating 58, 31, and 16% of that pore space, respectively. From the volume of methane gas produced during hydrate dissociation, we calculated the hydrate concentration in the pore space to be 70, 37, and 20% respectively. Based on these hydrate concentrations and our measured compressional wave speeds, we used a rock physics model to differentiate between potential pore-space hydrate distributions. Model results suggest methane hydrate cements unconsolidated sediment when forming in systems containing an abundant gas phase.

  17. Free gas in the regional hydrate stability zone: Implications for hydrate distribution and fracturing behavior

    NASA Astrophysics Data System (ADS)

    Daigle, H.; Dugan, B.

    2010-12-01

    We show that hydrate distribution and fracture genesis in the hydrate stability zone are largely governed by the phase of methane supply. In systems where methane is supplied primarily as free gas, hydrate saturation increases upwards in the hydrate stability zone, and fractures nucleate in the middle of the stability zone where hydrate saturation is highest. In systems where methane is supplied primarily as a dissolved phase in the pore water, hydrate saturation decreases upwards in the stability zone, and fractures nucleate at the base of the stability zone. These interpretations are based on our one-dimensional model that incorporates multiphase flow and free gas within the regional hydrate stability zone (RHSZ). The RHSZ is defined as the interval in which methane hydrate may occur at seawater salinity (3.35% by mass). As hydrate forms and excludes salt from the crystal structure, the porewater salinity increases. Free gas enters the RHSZ when the porewater salinity increases to the value required for three-phase (dissolved methane + gas hydrate + free gas) equilibrium. Our model also incorporates changes to capillary pressure as hydrate forms and occludes the pore system. We model the system until the excess pore pressure exceeds the vertical effective stress in the domain due to capillary effects and pore occlusion, at which point we assume fractures nucleate. We test our model at Hydrate Ridge, where methane supply is dominantly in the gas phase, and show that hydrate saturation increases upwards and fractures nucleate high within the stability zone, eventually allowing gas to vent to the seafloor. We also model Blake Ridge, where methane supply is dominantly in the dissolved phase, and show that hydrate saturation is greatest at the base of the stability zone; fractures nucleate here and in some cases could propagate through the regional hydrate stability zone, allowing methane-charged water to vent to the seafloor. These two systems represent endmembers of

  18. Understanding effect of structure and stability on transformation of CH4 hydrate to CO2 hydrate

    NASA Astrophysics Data System (ADS)

    Liu, Jinxiang; Yan, Yujie; Liu, Haiying; Xu, Jiafang; Zhang, Jun; Chen, Gang

    2016-03-01

    Understanding the transformation process of CH4 hydrate to CO2 hydrate is crucial to develop the CH4sbnd CO2 replacement technique for CH4 production and CO2 sequestration. Ab initio calculations show that the transformation will slightly distort the host lattice and decrease the binding strength of guest molecules, but it is a thermodynamically spontaneous process dominated by the entropic contribution. Moreover, ab initio molecular dynamics simulations suggest that the dynamics of the host lattice is independent on the guest molecules, while CO2 in hydrate exhibits slower translational and rotational motion than CH4 in hydrate.

  19. A realistic molecular model of cement hydrates

    PubMed Central

    Pellenq, Roland J.-M.; Kushima, Akihiro; Shahsavari, Rouzbeh; Van Vliet, Krystyn J.; Buehler, Markus J.; Yip, Sidney; Ulm, Franz-Josef

    2009-01-01

    Despite decades of studies of calcium-silicate-hydrate (C-S-H), the structurally complex binder phase of concrete, the interplay between chemical composition and density remains essentially unexplored. Together these characteristics of C-S-H define and modulate the physical and mechanical properties of this “liquid stone” gel phase. With the recent determination of the calcium/silicon (C/S = 1.7) ratio and the density of the C-S-H particle (2.6 g/cm3) by neutron scattering measurements, there is new urgency to the challenge of explaining these essential properties. Here we propose a molecular model of C-S-H based on a bottom-up atomistic simulation approach that considers only the chemical specificity of the system as the overriding constraint. By allowing for short silica chains distributed as monomers, dimers, and pentamers, this C-S-H archetype of a molecular description of interacting CaO, SiO2, and H2O units provides not only realistic values of the C/S ratio and the density computed by grand canonical Monte Carlo simulation of water adsorption at 300 K. The model, with a chemical composition of (CaO)1.65(SiO2)(H2O)1.75, also predicts other essential structural features and fundamental physical properties amenable to experimental validation, which suggest that the C-S-H gel structure includes both glass-like short-range order and crystalline features of the mineral tobermorite. Additionally, we probe the mechanical stiffness, strength, and hydrolytic shear response of our molecular model, as compared to experimentally measured properties of C-S-H. The latter results illustrate the prospect of treating cement on equal footing with metals and ceramics in the current application of mechanism-based models and multiscale simulations to study inelastic deformation and cracking. PMID:19805265

  20. Process development for elemental recovery from PGM tailings by thermochemical treatment: Preliminary major element extraction studies using ammonium sulphate as extracting agent.

    PubMed

    Mohamed, Sameera; van der Merwe, Elizabet M; Altermann, Wladyslaw; Doucet, Frédéric J

    2016-04-01

    Mine tailings can represent untapped secondary resources of non-ferrous, ferrous, precious, rare and trace metals. Continuous research is conducted to identify opportunities for the utilisation of these materials. This preliminary study investigated the possibility of extracting major elements from South African tailings associated with the mining of Platinum Group Metals (PGM) at the Two Rivers mine operations. These PGM tailings typically contain four major elements (11% Al2O3; 12% MgO; 22% Fe2O3; 34% Cr2O3), with lesser amounts of SiO2 (18%) and CaO (2%). Extraction was achieved via thermochemical treatment followed by aqueous dissolution, as an alternative to conventional hydrometallurgical processes. The thermochemical treatment step used ammonium sulphate, a widely available, low-cost, recyclable chemical agent. Quantification of the efficiency of the thermochemical process required the development and optimisation of the dissolution technique. Dissolution in water promoted the formation of secondary iron precipitates, which could be prevented by leaching thermochemically-treated tailings in 0.6M HNO3 solution. The best extraction efficiencies were achieved for aluminium (ca. 60%) and calcium (ca. 80%). 35% iron and 32% silicon were also extracted, alongside chromium (27%) and magnesium (25%). Thermochemical treatment using ammonium sulphate may therefore represent a promising technology for extracting valuable elements from PGM tailings, which could be subsequently converted to value-added products. However, it is not element-selective, and major elements were found to compete with the reagent to form water-soluble sulphate-metal species. Further development of this integrated process, which aims at achieving the full potential of utilisation of PGM tailings, is currently underway.

  1. Hydrate Control for Gas Storage Operations

    SciTech Connect

    Jeffrey Savidge

    2008-10-31

    The overall objective of this project was to identify low cost hydrate control options to help mitigate and solve hydrate problems that occur in moderate and high pressure natural gas storage field operations. The study includes data on a number of flow configurations, fluids and control options that are common in natural gas storage field flow lines. The final phase of this work brings together data and experience from the hydrate flow test facility and multiple field and operator sources. It includes a compilation of basic information on operating conditions as well as candidate field separation options. Lastly the work is integrated with the work with the initial work to provide a comprehensive view of gas storage field hydrate control for field operations and storage field personnel.

  2. Polyethylene oxide hydration in grafted layers

    NASA Astrophysics Data System (ADS)

    Dormidontova, Elena; Wang, Zilu

    Hydration of water soluble polymers is one of the key-factors defining their conformation and properties, similar to biopolymers. Polyethylene oxide (PEO) is one of the most important biomedical-applications polymers and is known for its reverse temperature solubility due to hydrogen bonding with water. As in many practical applications PEO chains are grafted to surfaces, e.g. of nanoparticles or planar surfaces, it is important to understand PEO hydration in such grafted layers. Using atomistic molecular dynamic simulations we investigate the details of molecular conformation and hydration of PEO end-grafted to gold surfaces. We analyze polymer and water density distribution as a function of distance from the surface for different grafting densities. Based on a detailed analysis of hydrogen bonding between polymer and water in grafted PEO layers, we will discuss the extent of PEO hydration and its implication for polymer conformation, mobility and layer properties. This research is supported by NSF (DMR-1410928).

  3. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Donn McGuire; Thomas Williams; Bjorn Paulsson; Alexander Goertz

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a drilling hazard by the oil and gas industry for years. Drilling engineers working in Russia, Canada and the USA have documented numerous problems, including drilling kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrates as a potential energy source agree that the resource potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained from physical samples taken from actual hydrate-bearing rocks. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The project team drilled and continuously cored the Hot Ice No. 1 well on Anadarko-leased acreage beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and used for determining physical characteristics of hydrates and surrounding rock. After the well was logged, a 3D vertical seismic profile (VSP) was recorded to calibrate the shallow geologic section with seismic data and to investigate techniques to better resolve lateral subsurface variations of potential hydrate-bearing strata. Paulsson Geophysical Services, Inc. deployed their 80 level 3C clamped borehole seismic receiver array in the wellbore to record samples every 25 ft. Seismic vibrators were successively positioned at 1185 different surface positions in a circular pattern around the wellbore. This technique generated a 3D image of the subsurface. Correlations were

  4. ConocoPhillips Gas Hydrate Production Test

    SciTech Connect

    Schoderbek, David; Farrell, Helen; Howard, James; Raterman, Kevin; Silpngarmlert, Suntichai; Martin, Kenneth; Smith, Bruce; Klein, Perry

    2013-06-30

    Work began on the ConocoPhillips Gas Hydrates Production Test (DOE award number DE-NT0006553) on October 1, 2008. This final report summarizes the entire project from January 1, 2011 to June 30, 2013.

  5. Hydration states of AFm cement phases

    SciTech Connect

    Baquerizo, Luis G.; Matschei, Thomas; Scrivener, Karen L.; Saeidpour, Mahsa; Wadsö, Lars

    2015-07-15

    The AFm phase, one of the main products formed during the hydration of Portland and calcium aluminate cement based systems, belongs to the layered double hydrate (LDH) family having positively charged layers and water plus charge-balancing anions in the interlayer. It is known that these phases present different hydration states (i.e. varying water content) depending on the relative humidity (RH), temperature and anion type, which might be linked to volume changes (swelling and shrinkage). Unfortunately the stability conditions of these phases are insufficiently reported. This paper presents novel experimental results on the different hydration states of the most important AFm phases: monocarboaluminate, hemicarboaluminate, strätlingite, hydroxy-AFm and monosulfoaluminate, and the thermodynamic properties associated with changes in their water content during absorption/desorption. This data opens the possibility to model the response of cementitious systems during drying and wetting and to engineer systems more resistant to harsh external conditions.

  6. Infrared Spectroscopy of Hydrated Nitromethane Anions

    NASA Astrophysics Data System (ADS)

    Marcum, Jesse C.; Weber, J. Mathias

    2009-06-01

    The hydration of molecular anions is still not as thoroughly explored as for atomic anions. We present IR spectra and quantum chemical calculations of hydrated nitromethane anions. In the monohydrate, the nitro group of the ion interacts with the water molecule via two hydrogen bonds, one from each O atom. This motif is partially conserved in the dihydrate. Adding the third water molecule results in a ring-like structure of the water ligands, each of which forms one H bond to one of the O atoms of the nitro group and another to a neighboring water ligand, reminiscent of the hydration motif of the heavier halides. Interestingly, while the methyl group is not directly involved in the interaction with the water ligands, its infrared signature is strongly affected by the changes in the intramolecular charge distribution through hydration.

  7. Overview: Gas hydrate geology and geography

    SciTech Connect

    Malone, R.D.

    1993-01-01

    Several geological factors which are directly responsible for the presence or absence of gas hydrates have been reviewed and are: tectonic position of the region; sedimentary environments; structural deformation; shale diapirism; hydrocarbon generation and migration; thermal regime in the hydrate formation zone (HFZ); pressure conditions; and hydrocarbon gas supply to the HFZ. Work on gas hydrate formation in the geological environment has made significant advances, but there is still much to be learned. Work is continuing in the deeper offshore areas through the Ocean Drilling Program, Government Agencies, and Industry. The pressure/temperature conditions necessary for formation has been identified for various compositions of natural gas through laboratory investigations and conditions for formation are being advanced through drilling in areas where gas hydrates exist.

  8. Natural gas hydrates: myths, facts and issues

    NASA Astrophysics Data System (ADS)

    Beauchamp, Benoı̂t

    2004-07-01

    Gas hydrates are solid-like substances naturally occurring beneath the oceans and in polar regions. They contain vast, and potentially unstable, reserves of methane and other natural gases. Many believe that, if released in the environment, the methane from hydrates would be a considerable hazard to marine ecosystems, coastal populations and infrastructures, or worse, that it would dangerously contribute to global warming. On the other hand, hydrates may contain enough natural gas to provide an energy supply assurance for the 21st century. This paper attempts to separate the myths, the facts and the issues that relate to natural gas hydrates beyond the doomsday environmental scenarios and overly optimistic estimates. To cite this article: B. Beauchamp, C. R. Geoscience 336 (2004).

  9. Indian National Gas Hydrate Program Expedition 01 report

    USGS Publications Warehouse

    Collett, Timothy S.; Riedel, M.; Boswell, R.; Presley, J.; Kumar, P.; Sathe, A.; Sethi, A.; Lall, M.; ,

    2015-01-01

    The Indian National Gas Hydrate Program Expedition 01 was designed to study the gas-hydrate occurrences off the Indian Peninsula and along the Andaman convergent margin with special emphasis on understanding the geologic and geochemical controls on the occurrence of gas hydrate in these two diverse settings. During Indian National Gas Hydrate Program Expedition 01, dedicated gas-hydrate coring, drilling, and downhole logging operations were conducted from 28 April 2006 to 19 August 2006.

  10. Physical properties of sediment containing methane gas hydrate

    USGS Publications Warehouse

    Winters, W.J.; Waite, W.F.; Mason, D.H.; Gilbert, L.Y.

    2005-01-01

    A study conducted by the US Geological Survey (USGS) on the formation, behavior, and properties of mixtures of gas hydrate and sediment is presented. The results show that the properties of host material influence the type and quantity of hydrates formed. The presence of hydrate during mechanical shear tests affects the measured sediment pore pressure. Sediment shear strength may be increased more than 500 percent by intact hydrate, but greatly weakened if the hydrate dissociates.

  11. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Ali Kadaster; Bill Liddell; Tommy Thompson; Thomas Williams; Michael Niedermayr

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project was a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope included drilling and coring a well (Hot Ice No. 1) on Anadarko leases beginning in FY 2003 and completed in 2004. During the first drilling season, operations were conducted at the site between January 28, 2003 to April 30, 2003. The well was spudded and drilled to a depth of 1403 ft. Due to the onset of warmer weather, work was then suspended for the season. Operations at the site were continued after the tundra was re-opened the following season. Between January 12, 2004 and March 19, 2004, the well was drilled and cored to a final depth of 2300 ft. An on-site core analysis laboratory was built and implemented for determining physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. Final efforts of the project are to correlate geology, geophysics, logs, and drilling and

  12. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2004-11-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored a well (the Hot Ice No. 1) on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in the

  13. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored a well (the Hot Ice No. 1) on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in the

  14. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Steve Runyon; Mike Globe; Kent Newsham; Robert Kleinberg; Doug Griffin

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project was a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope included drilling and coring a well (Hot Ice No. 1) on Anadarko leases beginning in FY 2003 and completed in 2004. During the first drilling season, operations were conducted at the site between January 28, 2003 to April 30, 2003. The well was spudded and drilled to a depth of 1403 ft. Due to the onset of warmer weather, work was then suspended for the season. Operations at the site were continued after the tundra was re-opened the following season. Between January 12, 2004 and March 19, 2004, the well was drilled and cored to a final depth of 2300 ft. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and

  15. Exploitation of subsea gas hydrate reservoirs

    NASA Astrophysics Data System (ADS)

    Janicki, Georg; Schlüter, Stefan; Hennig, Torsten; Deerberg, Görge

    2016-04-01

    Natural gas hydrates are considered to be a potential energy resource in the future. They occur in permafrost areas as well as in subsea sediments and are stable at high pressure and low temperature conditions. According to estimations the amount of carbon bonded in natural gas hydrates worldwide is two times larger than in all known conventional fossil fuels. Besides technical challenges that have to be overcome climate and safety issues have to be considered before a commercial exploitation of such unconventional reservoirs. The potential of producing natural gas from subsea gas hydrate deposits by various means (e.g. depressurization and/or injection of carbon dioxide) is numerically studied in the frame of the German research project »SUGAR«. The basic mechanisms of gas hydrate formation/dissociation and heat and mass transport in porous media are considered and implemented into a numerical model. The physics of the process leads to strong non-linear couplings between hydraulic fluid flow, hydrate dissociation and formation, hydraulic properties of the sediment, partial pressures and seawater solution of components and the thermal budget of the system described by the heat equation. This paper is intended to provide an overview of the recent development regarding the production of natural gas from subsea gas hydrate reservoirs. It aims at giving a broad insight into natural gas hydrates and covering relevant aspects of the exploitation process. It is focused on the thermodynamic principles and technological approaches for the exploitation. The effects occurring during natural gas production within hydrate filled sediment layers are identified and discussed by means of numerical simulation results. The behaviour of relevant process parameters such as pressure, temperature and phase saturations is described and compared for different strategies. The simulations are complemented by calculations for different safety relevant problems.

  16. Experimental Dissociation of Methane Hydrates Through Depressurization

    NASA Astrophysics Data System (ADS)

    Borgfeldt, T.; Flemings, P. B.; Meyer, D.; You, K.

    2015-12-01

    We dissociated methane hydrates by stepwise depressurization. The initial hydrates were formed by injecting gas into a cylindrical sample of brine-saturated, coarse-grained sand at hydrate-stable conditions with the intention of reaching three-phase equilibrium. The sample was initially at 1°C with a pore pressure of 1775 psi and a salinity of 7 wt. % NaBr. The depressurization setup consisted of one pump filled with tap water attached to the confining fluid port and a second pump attached to the inlet port where the methane was injected. Depressurization was conducted over sixteen hours at a constant temperature of 1°C. The pore pressure was stepwise reduced from 1775 psi to atmospheric pressure by pulling known volumes of gas from the sample. After each extraction, we recorded the instantaneous and equilibrium pore pressure. 0.503 moles of methane were removed from the sample. The pore pressure decreased smoothly and nonlinearly with the cumulative gas withdrawn from the sample. We interpret that hydrate began to dissociate immediately with depressurization, and it continued to dissociate when the pressure decreased below the three-phase pressure for 1°C and 0 wt. % salinity. Two breaks in slope in the pressure vs. mass extracted data are bounded by smooth, nonlinear curves with differing slopes on either side. We attribute the breaks to dissociation of three zones of hydrate concentration. We created a box model to simulate the experimental behavior. For a 10% initial gas saturation (estimated from the hydrate formation experiment and based on mass conservation), an initial hydrate saturation of 55% is required to match the total methane extracted from the sample. Future experiments will be conducted over a longer timespan while monitoring hydrate dissociation with CT imaging throughout the process.

  17. Electrical properties of polycrystalline methane hydrate

    USGS Publications Warehouse

    Du Frane, W. L.; Stern, L.A.; Weitemeyer, K.A.; Constable, S.; Pinkston, J.C.; Roberts, J.J.

    2011-01-01

    Electromagnetic (EM) remote-sensing techniques are demonstrated to be sensitive to gas hydrate concentration and distribution and complement other resource assessment techniques, particularly seismic methods. To fully utilize EM results requires knowledge of the electrical properties of individual phases and mixing relations, yet little is known about the electrical properties of gas hydrates. We developed a pressure cell to synthesize gas hydrate while simultaneously measuring in situ frequency-dependent electrical conductivity (σ). Synthesis of methane (CH4) hydrate was verified by thermal monitoring and by post run cryogenic scanning electron microscope imaging. Impedance spectra (20 Hz to 2 MHz) were collected before and after synthesis of polycrystalline CH4 hydrate from polycrystalline ice and used to calculate σ. We determined the σ of CH4 hydrate to be 5 × 10−5 S/m at 0°C with activation energy (Ea) of 30.6 kJ/mol (−15 to 15°C). After dissociation back into ice, σ measurements of samples increased by a factor of ~4 and Ea increased by ~50%, similar to the starting ice samples.

  18. Ground movements associated with gas hydrate production

    SciTech Connect

    Siriwardane, H.J.

    1992-10-01

    The mechanics of ground movements during hydrate production can be more closely simulated by considering similarities with ground movements associated with subsidence in permafrost regions than with gob compaction in a longwall mine. The purpose of this research work is to investigate the potential strata movements associated with hydrate production by considering similarities with ground movements in permafrost regions. The work primarily involves numerical modeling of subsidence caused by hydrate dissociation. The investigation is based on the theories of continuum mechanics , thermomechanical behavior of frozen geo-materials, and principles of rock mechanics and geomechanics. It is expected that some phases of the investigation will involve the use of finite element method, which is a powerful computer-based method which has been widely used in many areas of science and engineering. Parametric studies will be performed to predict expected strata movements and surface subsidence for different reservoir conditions and properties of geological materials. The results from this investigation will be useful in predicting the magnitude of the subsidence problem associated with gas hydrate production. The analogy of subsidence in permafrost regions may provide lower bounds for subsidence expected in hydrate reservoirs. Furthermore, it is anticipated that the results will provide insight into planning of hydrate recovery operations.

  19. Clathrate hydrates in the solar system

    NASA Technical Reports Server (NTRS)

    Miller, S. L.

    1985-01-01

    Clathrate hydrates are crystalline compounds in which an expanded ice lattice forms cages that contain gas molecules. There are two principal hydrate structures. Structure I, with a 12 A cubic unit cell, contains 46 water molecules and 8 cages of two types, giving an ideal formula (for CH4) of CH4.5.75H2O. The actual formula contains somewhat more water as the cages are not completely filled. Other examples that form Structure I hydrates are C2H6, C2H4, C2H2, CO2, SO2, OCS, Xe, H2S. Structure II, with a 17 A cubic unit cell, contains 136 water molecules, and 8 large and 16 small cages. The ideal formula for CHCl3 is CHCL3.17H2O. Other examples of Structure II hydrates include C3H8, C2H5Cl, acetone, and tetrahydrofuran. Small molecules such as Ar, Kr and probably N2 and O2 also form a Structure II hydrate. The small molecules occupy both the large and small cages, giving an ideal formula of Ar.5.67H2O. The conditions of pressure and temperature for hydrate formation are discussed.

  20. Surfactant effects on SF6 hydrate formation.

    PubMed

    Lee, Bo Ram; Lee, Ju Dong; Lee, Hyun Ju; Ryu, Young Bok; Lee, Man Sig; Kim, Young Seok; Englezos, Peter; Kim, Myung Hyun; Kim, Yang Do

    2009-03-01

    Sulfur hexafluoride (SF(6)) has been widely used in a variety of industrial processes, but it is one of the most potent greenhouse gases. For this reason, it is necessary to separate or collect it from waste gas streams. One separation method is through hydrate crystal formation. In this study, SF(6) hydrate was formed in aqueous surfactant solutions of 0.00, 0.01, 0.05, 0.15 and 0.20 wt% to investigate the effects of surfactants on the hydrate formation rates. Three surfactants, Tween 20 (Tween), sodium dodecyl sulfate (SDS) and linear alkyl benzene sulfonate (LABS), were tested in a semi-batch stirred vessel at the constant temperature and pressures of 276.2 K and 0.78 MPa, respectively. All surfactants showed kinetic promoter behavior for SF(6) hydrate formation. It was also found that SF(6) hydrate formation proceeded in two stages with the second stage being the most rapid. In situ Raman spectroscopy analysis revealed that the increased gas consumption rate with the addition of surfactant was possibly due to the increased gas filling rate in the hydrate cavity.

  1. Measurement of clathrate hydrates via Raman spectroscopy

    USGS Publications Warehouse

    Sum, A.K.; Burruss, R.C.; Sloan, E.D.

    1997-01-01

    Raman spectra of clathrate hydrate guest molecules are presented for three known structures (I (sI), II (sII), and H (sH)) in the following systems: CH4 (sI), CO2 (sI), C3H8 (sII), CH4 + CO2 (sI), CD4 + C3H8 (sII), CH4 + N2 (sI), CH4 + THF-d8 (sII), and CH4 + C7D14 (sH). Relative occupancy of CH4 in the large and small cavities of sI were determined by deconvoluting the ??1 symmetric bands, resulting in hydration numbers of 6.04 ?? 0.03. The frequency of the ??1 bands for CH4 in structures I, II, and H differ statistically, so that Raman spectroscopy is a potential tool to identify hydrate crystal structure. Hydrate guest compositions were also measured for two vapor compositions of the CH4 + CO2 system, and they compared favorably with predictions. The large cavities were measured to be almost fully occupied by CH4 and CO2, whereas only a small fraction of the small cavities are occupied by CH4. No CO2 was found in the small cavities. Hydration numbers from 7.27 to 7.45 were calculated for the mixed hydrate.

  2. Carbon Monoxide as an Electron Donor for the Biological Reduction of Sulphate

    PubMed Central

    Parshina, Sofiya N.; Sipma, Jan; Henstra, Anne Meint; Stams, Alfons J. M.

    2010-01-01

    Several strains of Gram-negative and Gram-positive sulphate-reducing bacteria (SRB) are able to use carbon monoxide (CO) as a carbon source and electron donor for biological sulphate reduction. These strains exhibit variable resistance to CO toxicity. The most resistant SRB can grow and use CO as an electron donor at concentrations up to 100%, whereas others are already severely inhibited at CO concentrations as low as 1-2%. Here, the utilization, inhibition characteristics, and enzymology of CO metabolism as well as the current state of genomics of CO-oxidizing SRB are reviewed. Carboxydotrophic sulphate-reducing bacteria can be applied for biological sulphate reduction with synthesis gas (a mixture of hydrogen and carbon monoxide) as an electron donor. PMID:20628586

  3. Effect of zinc sulphate on infarct size in experimental myocardial infarction in dogs.

    PubMed

    Lal, A

    1991-08-01

    The effect of zinc sulphate on myocardial infarct size following left coronary artery branch occlusion in dogs was studied. Zinc sulphate (10 mg/kg) was administered po, 24 h and 2 h before coronary occlusion in one group of animals. The area at risk was visualised by methylene blue injected intraventricularly. The infarcted area was visualised by triphenyl tetrazolium chloride staining. The infarct size expressed as a percentage of risk zone was 76.54 +/- 3.01 per cent (mean +/- SE) in the control group and 37.96 +/- 2.20 per cent in the zinc sulphate group (P less than 0.001). Zinc sulphate appears to be a potent prophylactic agent for limiting the size of myocardial infarct in the dogs.

  4. Magnesium stearate increases salbutamol sulphate dispersion: what is the mechanism?

    PubMed

    Tay, Tracy; Das, Shyamal; Stewart, Peter

    2010-01-01

    The objective was to understand the mechanism of enhancement in salbutamol sulphate (SS) respiratory deposition through addition of magnesium stearate (MgSt). The mixing of MgSt with micronized SS occurred using a Turbula mixer (101 rpm), whilst varying mixing time and MgSt concentration and size. Deposition of SS was determined by a twin-stage impinger. Particle size distributions were obtained using the Malvern Mastersizer 2000. Morphology was examined by scanning electron microscopy and surface energy determined using inverse gas chromatography. Mixing of SS with increasing concentrations of MgSt improved dispersion (FPF of 3.3% using 1% w/w MgSt, 4.5% using 5% w/w MgSt and 7.8% using 10% w/w MgSt compared with 1.4% of pure SS for 20mg doses) when mixed for 0.5h; SS dispersion improved further after 3.5h of mixing. In addition to the action of the MgSt in coating SS particles, a greater understanding of the function of MgSt particles in acting as micro-carriers and in changing the mixture structure through incorporation into agglomerates has been achieved. The mechanistic understanding of improvement in drug deposition using MgSt will allow more directed strategies to be employed in designing powder formulations for inhalation.

  5. Particle engineering using sonocrystallization: salbutamol sulphate for pulmonary delivery.

    PubMed

    Dhumal, Ravindra S; Biradar, Shailesh V; Paradkar, Anant R; York, Peter

    2009-02-23

    The aim of present work was to produce fine elongated crystals of salbutamol sulphate (SS) by sonocrystallization for pulmonary delivery and compare with micronized and spray dried SS (SDSS) for in vitro aerosolization behavior. Application of ultrasound during anti-solvent crystallization resulted in fine elongated crystals (sonocrystallized SS; SCSS) compared to aggregates of large irregular crystals obtained without sonication. Higher sonication amplitude, time, concentration and lower processing temperatures favored formation of smaller crystals with narrow particle size distribution (PSD). SCSS was separated from dispersion by spray drying in the form of loose aggregates (SD-SCSS). The fine particle fraction (FPF) of formulations with coarse lactose carrier in cascade impactor increased from 16.66% for micronized SS to 31.12% for SDSS (obtained by spray drying aqueous SS solution) and 44.21% for SD-SCSS, due to reduced cohesive/adhesive forces and aerodynamic size by virtue of elongated shape of crystals. SD-SCSS was stable without any change in crystallinity and aerodynamic behavior for 3 months at 40 degrees C/75% RH, but amorphous SDSS showed recrystallization with poor aerosolization performance on storage. Sonocrystallization, a rapid and simple technique is reported for production of SS crystals suitable for inhalation delivery. PMID:18996462

  6. Immunomodulatory and anti-inflammatory effects of chondroitin sulphate

    PubMed Central

    du Souich, Patrick; García, Antonio G; Vergés, Josep; Montell, Eulàlia

    2009-01-01

    Chondroitin sulphate (CS) is a natural glycosaminoglycan present in the extracellular matrix and is formed by the 1–3 linkage of D-glucuronic acid to N-acetylgalactosamine. In chondrocytes, CS diminishes interleukin-1 p (IL-1p)-induced increases in p38 mitogen-activated protein kinase (p38MAPK) and signal-regulated kinase 1/2 (Erk1/2) phosphorylation, and decreases nuclear factor-KB (NF-kB) nuclear translocation and as a consequence, reduces the formation of pro-inflammatory cytokines, IL-1 p and TNF-a, and pro-inflammatory enzymes, such as phospholipase A2 (PLA2), cyclooxygenase 2 (COX-2) and nitric oxide synthase-2 (NOS-2). The mechanism of action of CS explains its beneficial effect on the cartilage, synovial membrane and subchondral bone. On the other hand, in vivo, CS given orally prevents hepatic NF-κB nuclear translocation, suggesting that systemic CS may elicit an anti-inflammatory effect in many tissues besides the articulation. There is preliminary evidence showing that in human beings, CS may be of benefit in other diseases where inflammation is an essential marker, such as psoriasis and atherosclerosis. The review of the literature suggest that CS might also be of interest for the treatment of other diseases with an inflammatory and/or autoimmune character, such as inflammatory bowel disease, degenerative diseases of the central nervous system and stroke, multiple sclerosis and other autoimmune diseases. PMID:19522843

  7. Copper remediation by Eichhornia spp. and sulphate-reducing bacteria.

    PubMed

    Dave, Shailesh; Damani, Maitry; Tipre, Devayani

    2010-01-15

    Eichhornia spp. biomass was collected from Chandola Lake, Ahmedabad, Gujarat, India. Point of zero charge of the biomass was pH 7.3. Flask study showed pH 5 and 2-3h contact time as optimum conditions for copper sorption with 67.25% copper removal. At the end of 24h of contact time, copper removal reached to 85.0%, from 100 ppm copper containing solution. Copper loading capacity of the biomass ranged between 9.9 and 28.5 mg g(-1) of biomass. To understand the interaction among pH, temperature, presence of nickel and zinc in the system, 2(4) factorial experiment was performed. Under the experimental conditions pH and interactions between pH-nickel, temperature-pH and temperature-pH-nickel-zinc were found to be significant with 60-74.7% copper removal. Langmuir isotherm was better fit as compared to Freundlich isotherm and pseudo-second order equation gave R(2) of 0.999 for biosorption kinetic of Eichhornia biomass. Reactor study showed 90% overall copper removal from 24 L of copper containing waste studied and sulphate-reducing bacteria played a significant role. SEMquant element analysis showed increase from 41.66% to 53.93%, 1.02-19.73% and 0.0-12.39% of chloride, aluminium and copper respectively in the loaded biomass as compare to unexposed biomass.

  8. Copper remediation by Eichhornia spp. and sulphate-reducing bacteria.

    PubMed

    Dave, Shailesh; Damani, Maitry; Tipre, Devayani

    2010-01-15

    Eichhornia spp. biomass was collected from Chandola Lake, Ahmedabad, Gujarat, India. Point of zero charge of the biomass was pH 7.3. Flask study showed pH 5 and 2-3h contact time as optimum conditions for copper sorption with 67.25% copper removal. At the end of 24h of contact time, copper removal reached to 85.0%, from 100 ppm copper containing solution. Copper loading capacity of the biomass ranged between 9.9 and 28.5 mg g(-1) of biomass. To understand the interaction among pH, temperature, presence of nickel and zinc in the system, 2(4) factorial experiment was performed. Under the experimental conditions pH and interactions between pH-nickel, temperature-pH and temperature-pH-nickel-zinc were found to be significant with 60-74.7% copper removal. Langmuir isotherm was better fit as compared to Freundlich isotherm and pseudo-second order equation gave R(2) of 0.999 for biosorption kinetic of Eichhornia biomass. Reactor study showed 90% overall copper removal from 24 L of copper containing waste studied and sulphate-reducing bacteria played a significant role. SEMquant element analysis showed increase from 41.66% to 53.93%, 1.02-19.73% and 0.0-12.39% of chloride, aluminium and copper respectively in the loaded biomass as compare to unexposed biomass. PMID:19747776

  9. Interplay between transglutaminases and heparan sulphate in progressive renal scarring

    PubMed Central

    Burhan, Izhar; Furini, Giulia; Lortat-Jacob, Hugues; Atobatele, Adeola G.; Scarpellini, Alessandra; Schroeder, Nina; Atkinson, John; Maamra, Mabrouka; Nutter, Faith H.; Watson, Philip; Vinciguerra, Manlio; Johnson, Timothy S.; Verderio, Elisabetta A. M.

    2016-01-01

    Transglutaminase-2 (TG2) is a new anti-fibrotic target for chronic kidney disease, for its role in altering the extracellular homeostatic balance leading to excessive build-up of matrix in kidney. However, there is no confirmation that TG2 is the only transglutaminase involved, neither there are strategies to control its action specifically over that of the conserved family-members. In this study, we have profiled transglutaminase isozymes in the rat subtotal nephrectomy (SNx) model of progressive renal scarring. All transglutaminases increased post-SNx peaking at loss of renal function but TG2 was the predominant enzyme. Upon SNx, extracellular TG2 deposited in the tubulointerstitium and peri-glomerulus via binding to heparan sulphate (HS) chains of proteoglycans and co-associated with syndecan-4. Extracellular TG2 was sufficient to activate transforming growth factor-β1 in tubular epithelial cells, and this process occurred in a HS-dependent way, in keeping with TG2-affinity for HS. Analysis of heparin binding of the main transglutaminases revealed that although the interaction between TG1 and HS is strong, the conformational heparin binding site of TG2 is not conserved, suggesting that TG2 has a unique interaction with HS within the family. Our data provides a rationale for a novel anti-fibrotic strategy specifically targeting the conformation-dependent TG2-epitope interacting with HS. PMID:27694984

  10. Indoxyl sulphate and kidney disease: Causes, consequences and interventions.

    PubMed

    Ellis, Robert J; Small, David M; Vesey, David A; Johnson, David W; Francis, Ross; Vitetta, Luis; Gobe, Glenda C; Morais, Christudas

    2016-03-01

    In the last decade, chronic kidney disease (CKD), defined as reduced renal function (glomerular filtration rate (GFR) < 60 mL/min per 1.73 m(2) ) and/or evidence of kidney damage (typically manifested as albuminuria) for at least 3 months, has become one of the fastest-growing public health concerns worldwide. CKD is characterized by reduced clearance and increased serum accumulation of metabolic waste products (uremic retention solutes). At least 152 uremic retention solutes have been reported. This review focuses on indoxyl sulphate (IS), a protein-bound, tryptophan-derived metabolite that is generated by intestinal micro-organisms (microbiota). Animal studies have demonstrated an association between IS accumulation and increased fibrosis, and oxidative stress. This has been mirrored by in vitro studies, many of which report cytotoxic effects in kidney proximal tubular cells following IS exposure. Clinical studies have associated IS accumulation with deleterious effects, such as kidney functional decline and adverse cardiovascular events, although causality has not been conclusively established. The aims of this review are to: (i) establish factors associated with increased serum accumulation of IS; (ii) report effects of IS accumulation in clinical studies; (iii) critique the reported effects of IS in the kidney, when administered both in vivo and in vitro; and (iv) summarize both established and hypothetical therapeutic options for reducing serum IS or antagonizing its reported downstream effects in the kidney.

  11. Magnesium stearate increases salbutamol sulphate dispersion: what is the mechanism?

    PubMed

    Tay, Tracy; Das, Shyamal; Stewart, Peter

    2010-01-01

    The objective was to understand the mechanism of enhancement in salbutamol sulphate (SS) respiratory deposition through addition of magnesium stearate (MgSt). The mixing of MgSt with micronized SS occurred using a Turbula mixer (101 rpm), whilst varying mixing time and MgSt concentration and size. Deposition of SS was determined by a twin-stage impinger. Particle size distributions were obtained using the Malvern Mastersizer 2000. Morphology was examined by scanning electron microscopy and surface energy determined using inverse gas chromatography. Mixing of SS with increasing concentrations of MgSt improved dispersion (FPF of 3.3% using 1% w/w MgSt, 4.5% using 5% w/w MgSt and 7.8% using 10% w/w MgSt compared with 1.4% of pure SS for 20mg doses) when mixed for 0.5h; SS dispersion improved further after 3.5h of mixing. In addition to the action of the MgSt in coating SS particles, a greater understanding of the function of MgSt particles in acting as micro-carriers and in changing the mixture structure through incorporation into agglomerates has been achieved. The mechanistic understanding of improvement in drug deposition using MgSt will allow more directed strategies to be employed in designing powder formulations for inhalation. PMID:19748561

  12. Chitosan microparticles for sustaining the topical delivery of minoxidil sulphate.

    PubMed

    Gelfuso, Guilherme Martins; Gratieri, Taís; Simão, Patrícia Sper; de Freitas, Luís Alexandre Pedro; Lopez, Renata Fonseca Vianna

    2011-01-01

    Given the hypothesis that microparticles can penetrate the skin barrier along the transfollicular route, this work aimed to obtain and characterise chitosan microparticles loaded with minoxidil sulphate (MXS) and to study their ability to sustain the release of the drug, attempting a further application utilising them in a targeted delivery system for the topical treatment of alopecia. Chitosan microparticles, containing different proportions of MXS/polymer, were prepared by spray drying and were characterised by yield, encapsulation efficiency, size and morphology. Microparticles selected for further studies showed high encapsulation efficiency (∼82%), a mean diameter of 3.0 µm and a spherical morphology without porosities. When suspended in an ethanol/water solution, chitosan microparticles underwent instantaneous swelling, increasing their mean diameter by 90%. Release studies revealed that the chitosan microparticles were able to sustain about three times the release rate of MXS. This feature, combined with suitable size, confers to these microparticles the potential to target and improve topical therapy of alopecia with minoxidil. PMID:21824068

  13. Hydration during intense exercise training.

    PubMed

    Maughan, R J; Meyer, N L

    2013-01-01

    Hydration status has profound effects on both physical and mental performance, and sports performance is thus critically affected. Both overhydration and underhydration - if sufficiently severe - will impair performance and pose a risk to health. Athletes may begin exercise in a hypohydrated state as a result of incomplete recovery from water loss induced in order to achieve a specific body mass target or due to incomplete recovery from a previous competition or training session. Dehydration will also develop in endurance exercise where fluid intake does not match water loss. The focus has generally been on training rather than on competition, but sweat loss and fluid replacement in training may have important implications. Hypohydration may impair training quality and may also increase stress levels. It is unclear whether this will have negative effects (reduced training quality, impaired immunity) or whether it will promote a greater adaptive response. Hypohydration and the consequent hyperthermia, however, can enhance the effectiveness of a heat acclimation program, resulting in improved endurance performance in warm and temperate environments. Drinking in training may be important in enhancing tolerance of the gut when athletes plan to drink in competition. The distribution of water between body water compartments may also be important in the initiation and promotion of cellular adaptations to the training stimulus. PMID:23899752

  14. Variation in hydration forces between neutral phospholipid bilayers: evidence for hydration attraction.

    PubMed

    Rand, R P; Fuller, N; Parsegian, V A; Rau, D C

    1988-10-01

    It is now generally recognized that hydration forces dominate close interactions of lipid hydrophilic surfaces. The commonality of their characteristics has been reasonably established. However, differences in measured net repulsion, particularly evident when phosphatidylethanolamine (PE) and phosphatidylcholine (PC) bilayers are compared, suggest there exists a variety of behavior wider than expected from earlier models of hydration and fluctuation repulsion balanced by van der Waals attraction. To find a basis for this diverse behavior, we have looked more closely at measured structural parameters, degrees of hydration, and interbilayer repulsive forces for the lamellar phases of the following lipids: 1-palmitoyl-2-oleoyl-PE (POPE), egg PE, transphosphatidylated egg PE (egg PE-T), mono- and dimethylated egg PE-T (MMPE and DMPE), 1-stearoyl-2-oleoyl-PC (SOPC), and mixtures of POPE and SOPC. POPE and SOPC bilayers differ not only in their maximum degrees of hydration but also in the empirical hydration force coefficients and decay lengths that characterize their interaction. When mixed with POPE, SOPC effects sudden and disproportionate increases in hydration. POPE, egg PE, and egg PE-T differ in their degree of hydration, molecular area, and hydration repulsion. A single methylation of egg PE-T almost completely converts its hydration and bilayer repulsive properties to those of egg PC; little progression of hydration is seen with successive methylations. In order to reconcile these observations with the conventional scheme of balancing interbilayer hydration and fluctuation-enhanced repulsion with van der Waals attraction, it is necessary to relinquish the fundamental idea that the decay of hydration forces is a constant determined by the properties of the aqueous medium. Alternatively, one can retain that fundamental idea if one recognizes the possibility that polar group hydration has an attractive component to it. In the latter view, that attractive component

  15. High capacity nickel battery material doped with alkali metal cations

    DOEpatents

    Jackovitz, John F.; Pantier, Earl A.

    1982-05-18

    A high capacity battery material is made, consisting essentially of hydrated Ni(II) hydroxide, and about 5 wt. % to about 40 wt. % of Ni(IV) hydrated oxide interlayer doped with alkali metal cations selected from potassium, sodium and lithium cations.

  16. Isopycnic-centrifugation studies in caesium chloride and in caesium sulphate on dermatan sulphate proteoglycans from bovine sclera

    PubMed Central

    Sheehan, John K.; Carlstedt, Ingemar; Cöster, Lars; Malmström, Anders; Fransson, Lars-Ȧke

    1981-01-01

    1. Two proteodermatan sulphate species from bovine sclera (fractions PG-I and PG-II) separable by gel chromatography were studied by isopycnic centrifugations in CsCl and Cs2SO4 both in an analytical and a preparative mode. 2. In CsCl, fraction PG-I formed a broad band at a density ρ=1.75g/ml whereas fraction PG-II banded sharply at ρ=1.64g/ml. However, in Cs2SO4, fraction PG-II banded at ρ=1.51g/ml and fraction PG-I at ρ=1.40g/ml, a reversal of the relative banding positions of the two species in CsCl. 3. Preparative isopycnic centrifugations in the two caesium salts permitted further subfractionation of fractions PG-I and PG-II. In both CsCl and Cs2SO4 fraction PG-I was split into subfractions that varied greatly in uronate/protein ratios but had very similar uronate composition. In contrast, isopycnic centrifugation of fraction PG-II in Cs2SO4 gave rise to subfractions with similar uronate/protein ratios but markedly different uronate composition (iduronate content, 88–42%). 4. Subfractions of fractions PG-I and PG-II obtained in preparative centrifugations in CsCl or Cs2SO4 were examined in the analytical ultracentrifuge. These subfractions banded at discrete positions in the gradient. Estimations of apparent molecular weight for these subfractions from data from the analytical isopycnic centrifugations gave values that were much higher (around 1×106) than were those obtained previously for their `monomeric' states (fraction PG-I 160000–410000, and fraction PG-II 70000–130000). 5. In CsCl, fraction PG-I may be subfractionated according to the number of side chains in the molecule. Fraction PG-I increased its net solvation (i.e. lowered its buoyant density) to a larger extent than did fraction PG-II in going from CsCl to Cs2SO4 (i.e. from lower to higher water activity). It is proposed that the presence of large amounts of iduronate in fraction PG-II makes these molecules relatively less solvated in Cs2SO4. Thus the uronate composition may be an

  17. Sulphate fertilization ameliorates long-term aluminum toxicity symptoms in perennial ryegrass (Lolium perenne).

    PubMed

    Wulff-Zottele, Cristian; Hesse, Holger; Fisahn, Joachim; Bromke, Mariusz; Vera-Villalobos, Hernán; Li, Yan; Frenzel, Falko; Giavalisco, Patrick; Ribera-Fonseca, Alejandra; Zunino, Ligia; Caruso, Immcolata; Stohmann, Evelyn; Mora, Maria de la Luz

    2014-10-01

    Effects of the oxanion sulphate on plant aluminum (Al(3+)) detoxification mechanisms are not well understood. Therefore, holistic physiological and biochemical modifications induced by progressively increased doses of sulphate fertilization in the presence of long-term Al(3+) stress were investigated in the aluminum sensitive perennial ryegrass (Lolium perenne L. cvJumbo). Plant growth inhibition induced by Al(3+) was decreased in response to increasing doses of sulphate supply. Aluminum concentrations measured in roots of perennial ryegrass by atomic absorption spectrometry declined significantly with increasing sulphate concentrations. In parallel, we determined a rise of sulphur in shoots and roots of perennial ryegrass. Inclusion of up to 360 μM of sulphate enhanced cysteine and glutathione biosynthesis in Al(3+) (1.07 μM) treated plants. This increase of thiol-containing compounds favored all modifications in the glutathione redox balance, declining lipid peroxidation, decreasing the activity of superoxide dismutase, and modifying the expression of proteins involved in the diminution of Al(3+) toxicity in roots. In particular, proteome analysis by 1D-SDS-PAGE and LC-MS/MS allowed to identify up (e.g. vacuolar proton ATPase, proteosome β subunit, etc) and down (Glyoxilase I, Ascorbate peroxidase, etc.) regulated proteins induced by Al(3+) toxicity symptoms in roots. Although, sulphate supply up to 480 μM caused a reduction in Al(3+) toxicity symptoms, it was not as efficient as compared to 360 μM sulphate fertilization. These results suggest that sulphate fertilization ameliorates Al(3+) toxicity responses in an intracellular specific manner within Lolium perenne.

  18. Isobolographic analysis of the interaction between cadmium (II) and sodium sulphate: toxicological consequences.

    PubMed

    Mera, Roi; Torres, Enrique; Abalde, Julio

    2016-02-01

    Sulphate is an essential nutrient for autotrophic organisms and has been shown to have important implications in certain processes of tolerance to cadmium toxicity. Sodium sulphate is the main salt of sulphate in the natural environments. The concentration of this salt is increasing in the aquatic environments due to environmental pollution. The aim of this study was to investigate, using an analysis of isobolograms, the type and the degree of the interaction between Cd(II) and sodium sulphate in the freshwater microalga Chlamydomonas moewusii. Two blocks of experiments were performed, one at sub-optimal sodium sulphate concentrations (<14.2 mg/L) and the other at supra-optimal concentrations (>14.2 mg/L). Three fixed ratios (2:1, 1:1, and 1:2) of the individual EC50 for cadmium and sodium sulphate were used within each block. The isobolographic analysis of interaction at sub-optimal concentrations showed a stronger antagonistic effect with values of interaction index (γ) between 1.46 and 3.4. However, the isobologram with sodium sulphate at supra-optimal concentrations revealed a slight but significant synergistic effect between both chemicals with an interaction index between 0.54 and 0.64. This synergic effect resulted in the potentiation of the toxic effects of cadmium, synergy that was related to the increase of the ionic strength and of two species of cadmium, CdSO4 (aq), and Cd(SO4)2(2-) , in the medium. Results of the current study suggest that sodium sulphate is able to perform a dual antagonist/synergist effect on cadmium toxicity. This role was concentration dependent.

  19. Comparison of physical and inhalation properties of spray-dried and micronized terbutaline sulphate.

    PubMed

    Thi, Thanh Huong Hoang; Danède, Florence; Descamps, Marc; Flament, Marie-Pierre

    2008-09-01

    Terbutaline sulphate particles, for use in dry powder inhaler formulations, were prepared by spray-drying, using a Büchi 190 mini spray dryer. Spray-drying conditions were chosen to allow the production of spray-dried terbutaline sulphate with a size similar to micronized terbutaline sulphate, that is to say about 2.9 microm of volume mean diameter. The physical properties and in vitro inhalation behaviour of micronized and spray-dried terbutaline sulphate were compared. X-ray diffraction, DSC, SEM and laser size analysis were investigated. Spray-dying produced spherically shaped particles with amorphous structure. After blending with different lactoses, adhesion and aerodynamic properties were investigated. Evaluation of adhesion was carried out with a mechanical sieve and an Alpine air-jet sieve. The adhesion of terbutaline sulphate on the lactoses tested was lower in the case of the spray-dried drug. Aerodynamic evaluation of fine particle dose and emitted dose was conducted using a twin stage impactor. The emitted doses and the fine particle doses were higher with the spray-dried terbutaline sulphate. The Alpine air-jet sieve assays showed that there was a correlation between drug separation from a carrier by sieving and that obtained from longer in vitro deposition studies. There was a linear relationship between the adhesion characteristics and the fine particle dose. PMID:18504120

  20. Sulphate production by Paracoccus pantotrophus ATCC 35512 from different sulphur substrates: sodium thiosulphate, sulphite and sulphide.

    PubMed

    Meyer, Daniel Derrossi; Andrino, Felipe Gabriel; Possedente de Lira, Simone; Fornaro, Adalgiza; Corção, Gertrudes; Brandelli, Adriano

    2016-01-01

    One of the problems in waste water treatment plants (WWTPs) is the increase in emissions of hydrogen sulphide (H2S), which can cause damage to the health of human populations and ecosystems. To control emissions of this gas, sulphur-oxidizing bacteria can be used to convert H2S to sulphate. In this work, sulphate detection was performed by spectrophotometry, ion chromatography and atomic absorption spectrometry, using Paracoccus pantotrophus ATCC 35512 as a reference strain growing in an inorganic broth supplemented with sodium thiosulphate (Na2S2O3·5H2O), sodium sulphide (Na2S) or sodium sulphite (Na2SO3), separately. The strain was metabolically competent in sulphate production. However, it was only possible to observe significant differences in sulphate production compared to abiotic control when the inorganic medium was supplemented with sodium thiosulphate. The three methods for sulphate detection showed similar patterns, although the chromatographic method was the most sensitive for this study. This strain can be used as a reference for sulphate production in studies with sulphur-oxidizing bacteria originating from environmental samples of WWTPs.

  1. Application of sugarcane bagasse for passive anaerobic biotreatment of sulphate rich wastewaters

    NASA Astrophysics Data System (ADS)

    Hussain, Ali; Qazi, Javed Iqbal

    2016-06-01

    Biological treatment of sulphate-rich wastewaters employing dissimilatory sulphate reducing bacteria as remedial agents is an attractive technique and has gained importance in the last few years. Industrial effluents enriched with sulphates are generally deficient in electron donors. And thus cannot be treated biologically without supplementation of carbon through an external source. For scalable operations, however, the carbon source must not be expensive. In this context, present study reports the efficiency of biological sulphate reduction using sugarcane bagasse as a cost-effective carbon source. An average 0.00391 ± 0.001 gL-1 day-1 (3.91 mgL-1 day-1) sulphate reduction was observed reaching maximally to 0.00466 ± 0.001 gL-1 day-1 (4.66 mgL-1 day-1) while employing Desulfovibrio fructosovorans-HAQ2 and Desulfovibrio piger-HAQ6 in a 60-day trial of anaerobic incubation using sugarcane bagasse as growth substrate. These findings will be helpful in developing economical bioremediation processes tending to operate for a longer period of time to reduce sulphate contents of contaminated waters.

  2. Assessment of deterioration in RHA-concrete due to magnesium sulphate attack

    NASA Astrophysics Data System (ADS)

    Habeeb, G. A.; Mahmud, H. B.; Hamid, N. B. A. A.

    2010-12-01

    The assessment of magnesium sulphate attack on concretes containing rice husk ash (RHA, 20wt% of the cementitious materials) with various average particle sizes was investigated. The total cementitious materials were 390 kg and the water-to-binder ratio (W/B) was 0.53 for all mixtures. Specimens were initially cured in water for 7 d and then immersed in the 3wt% magnesium sulphate solution for up to 111 d of exposure. The specimens were subjected to drying-wetting cycles to accelerate sulphate attack. In addition to the visual monitoring of the specimens, the concrete specimens were subsequently tested for compressive strength, dynamic modulus of elasticity, and length and mass changes. The results show that the specimens exposed to sulphate attack exhibit higher strength and dynamic modulus than those kept in water. The length change is negligible and can be attributed to the normal swelling of concrete. On the other hand, concretes suffers mass loss and surface spalling and softening; the fine RHA-concrete results in a better resistance. For the accelerated sulphate attack method used in this study, mass change and visual monitoring are recommended for assessing the deterioration degree and the effectiveness of supplementary cementitious materials to resist sulphate attack.

  3. Sulphated glycosaminoglycans and proteoglycans in the developing vertebral column of juvenile Atlantic salmon (Salmo salar).

    PubMed

    Hannesson, Kirsten O; Ytteborg, Elisabeth; Takle, Harald; Enersen, Grethe; Bæverfjord, Grete; Pedersen, Mona E

    2015-08-01

    In the present study, the distribution of sulphated glycosaminoglycans (GAGs) in the developing vertebral column of Atlantic salmon (Salmo salar) at 700, 900, 1100 and 1400 d° was examined by light microscopy. The mineralization pattern was outlined by Alizarin red S and soft structures by Alcian blue. The temporal and spatial distribution patterns of different types of GAGs: chondroitin-4-sulphate/dermatan sulphate, chondroitin-6-sulphate, chondroitin-0-sulphate and keratan sulphate were addressed by immunohistochemistry using monoclonal antibodies against the different GAGs. The specific pattern obtained with the different antibodies suggests a unique role of the different GAG types in pattern formation and mineralization. In addition, the distribution of the different GAG types in normal and malformed vertebral columns from 15 g salmon was compared. A changed expression pattern of GAGs was found in the malformed vertebrae, indicating the involvement of these molecules during the pathogenesis. The molecular size of proteoglycans (PGs) in the vertebrae carrying GAGs was analysed with western blotting, and mRNA transcription of the PGs aggrecan, decorin, biglycan, fibromodulin and lumican by real-time qPCR. Our study reveals the importance of GAGs in development of vertebral column also in Atlantic salmon and indicates that a more comprehensive approach is necessary to completely understand the processes involved.

  4. Development of an Inhaled Sustained Release Dry Powder Formulation of Salbutamol Sulphate, an Antiasthmatic Drug

    PubMed Central

    Kumaresan, C.; Sathishkumar, K.

    2016-01-01

    The present research was aimed to develop and characterize a sustained release dry powder inhalable formulation of salbutamol sulphate. The salbutamol sulphate microparticles were prepared by solvent evaporation method using biodegradable polymer poly (D,L-lactic-co-glycolic acid) to produce salbutamol sulphate microparticle mixed with carrier respirable grade lactose for oral inhalation of dry powder. The drug content were estimated to produce 1 mg sustained release salbutamol sulphate per dose. Total four formulations K1, K2, K3 and K4 were prepared with 1:1, 1:2, 1:3, 1:4 ratio of salbutamol sulphate:poly (D,L-lactic-co-glycolic acid). The developed formulations were studied for physicochemical properties, in vitro drug relase and Anderson cascade impaction studies. The prepared formulations effectively releases drug for 12 h in diffusion bag studies. Based on dissolution performance the 1:1 ratio of salbutamol sulphate:poly (D,L-lactic-co-glycolic acid) produces in vitro release 92.57% at 12 h and having particle size of microparticles (D0.5μm) 5.02±0.6 and the pulmonary deposition of dry powder 34.5±3.21 (respiratory fraction in percentage). PMID:27168692

  5. Development of an Inhaled Sustained Release Dry Powder Formulation of Salbutamol Sulphate, an Antiasthmatic Drug.

    PubMed

    Kumaresan, C; Sathishkumar, K

    2016-01-01

    The present research was aimed to develop and characterize a sustained release dry powder inhalable formulation of salbutamol sulphate. The salbutamol sulphate microparticles were prepared by solvent evaporation method using biodegradable polymer poly (D,L-lactic-co-glycolic acid) to produce salbutamol sulphate microparticle mixed with carrier respirable grade lactose for oral inhalation of dry powder. The drug content were estimated to produce 1 mg sustained release salbutamol sulphate per dose. Total four formulations K1, K2, K3 and K4 were prepared with 1:1, 1:2, 1:3, 1:4 ratio of salbutamol sulphate:poly (D,L-lactic-co-glycolic acid). The developed formulations were studied for physicochemical properties, in vitro drug relase and Anderson cascade impaction studies. The prepared formulations effectively releases drug for 12 h in diffusion bag studies. Based on dissolution performance the 1:1 ratio of salbutamol sulphate:poly (D,L-lactic-co-glycolic acid) produces in vitro release 92.57% at 12 h and having particle size of microparticles (D0.5μm) 5.02±0.6 and the pulmonary deposition of dry powder 34.5±3.21 (respiratory fraction in percentage). PMID:27168692

  6. About transformation of the deep-water methane bubbles into hydrate powder and hydrate foam

    NASA Astrophysics Data System (ADS)

    Egorov, A. V.; Nigmatulin, R. I.; Rozhkov, A. N.; Sagalevich, A. M.; Chernyaev, E. S.

    2012-04-01

    During the Russian Academy of Sciences "MIRI na Baikale, 2008-2010" expedition, deep-water experiments with the bubbles of methane seeping from the bottom at depths 405, 860 and 1400 meters were carried out. These depths correspond to gas hydrate stability zone. Bubbles were caught by the trap which was looked like an inverted glass. It was found that the behavior of bubbles in a trap depends on the depth. At depth of 405 meters formation of hydrates was not observed. Having got to a trap at the depth of 860 meters, bubbles became covered by solid hydrate envelope, kept the initial form, and after a time period collapsed in a number of hydrate fragments which showed all properties of a granular matter. No visible changes in the hydrate granular matter were observed in the course of lifting it to a depth of 380 meters. Shallower, the decomposition of the hydrate granular matter into methane gas was observed. In the experiments at depth of 1400 meters the caught bubbles, becoming covered by hydrate envelope formed solid hydrate foam in the trap. At lifting this foam structure was deformed slightly but simultaneously a free gas left the foam and filled the trap. The volume of free gas in the trap at lifting varied according to the Boyle-Mariotte law.

  7. Aqueous phase hydration and hydrate acidity of perfluoroalkyl and n:2 fluorotelomer aldehydes.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2016-01-01

    The SPARC software program and comparative density functional theory (DFT) calculations were used to investigate the aqueous phase hydration equilibrium constants (Khyd) of perfluoroalkyl aldehydes (PFAlds) and n:2 fluorotelomer aldehydes (FTAlds). Both classes are degradation products of known industrial compounds and environmental contaminants such as fluorotelomer alcohols, iodides, acrylates, phosphate esters, and other derivatives, as well as hydrofluorocarbons and hydrochlorofluorocarbons. Prior studies have generally failed to consider the hydration, and subsequent potential hydrate acidity, of these compounds, resulting in incomplete and erroneous predictions as to their environmental behavior. In the current work, DFT calculations suggest that all PFAlds will be dominantly present as the hydrated form in aqueous solution. Both SPARC and DFT calculations suggest that FTAlds will not likely be substantially hydrated in aquatic systems or in vivo. PFAld hydrates are expected to have pKa values in the range of phenols (ca. 9 to 10), whereas n:2 FTAld hydrates are expected to have pKa values ca. 2 to 3 units higher (ca. 12 to 13). In order to avoid spurious modeling predictions and a fundamental misunderstanding of their fate, the molecular and/or dissociated hydrate forms of PFAlds and FTAlds need to be explicitly considered in environmental, toxicological, and waste treatment investigations. The results of the current study will facilitate a more complete examination of the environmental fate of PFAlds and FTAlds. PMID:26980678

  8. Hydrate-phobic surfaces: fundamental studies in clathrate hydrate adhesion reduction.

    PubMed

    Smith, J David; Meuler, Adam J; Bralower, Harrison L; Venkatesan, Rama; Subramanian, Sivakumar; Cohen, Robert E; McKinley, Gareth H; Varanasi, Kripa K

    2012-05-01

    Clathrate hydrate formation and subsequent plugging of deep-sea oil and gas pipelines represent a significant bottleneck for deep-sea oil and gas operations. Current methods for hydrate mitigation are expensive and energy intensive, comprising chemical, thermal, or flow management techniques. In this paper, we present an alternate approach of using functionalized coatings to reduce hydrate adhesion to surfaces, ideally to a low enough level that hydrodynamic shear stresses can detach deposits and prevent plug formation. Systematic and quantitative studies of hydrate adhesion on smooth substrates with varying solid surface energies reveal a linear trend between hydrate adhesion strength and the practical work of adhesion (γ(total)[1 + cos θ(rec)]) of a suitable probe liquid, that is, one with similar surface energy properties to those of the hydrate. A reduction in hydrate adhesion strength by more than a factor of four when compared to bare steel is achieved on surfaces characterized by low Lewis acid, Lewis base, and van der Waals contributions to surface free energy such that the practical work of adhesion is minimized. These fundamental studies provide a framework for the development of hydrate-phobic surfaces, and could lead to passive enhancement of flow assurance and prevention of blockages in deep-sea oil and gas operations.

  9. Controls on Gas Hydrate Formation and Dissociation

    SciTech Connect

    Miriam Kastner; Ian MacDonald

    2006-03-03

    The main objectives of the project were to monitor, characterize, and quantify in situ the rates of formation and dissociation of methane hydrates at and near the seafloor in the northern Gulf of Mexico, with a focus on the Bush Hill seafloor hydrate mound; to record the linkages between physical and chemical parameters of the deposits over the course of one year, by emphasizing the response of the hydrate mound to temperature and chemical perturbations; and to document the seafloor and water column environmental impacts of hydrate formation and dissociation. For these, monitoring the dynamics of gas hydrate formation and dissociation was required. The objectives were achieved by an integrated field and laboratory scientific study, particularly by monitoring in situ formation and dissociation of the outcropping gas hydrate mound and of the associated gas-rich sediments. In addition to monitoring with the MOSQUITOs, fluid flow rates and temperature, continuously sampling in situ pore fluids for the chemistry, and imaging the hydrate mound, pore fluids from cores, peepers and gas hydrate samples from the mound were as well sampled and analyzed for chemical and isotopic compositions. In order to determine the impact of gas hydrate dissociation and/or methane venting across the seafloor on the ocean and atmosphere, the overlying seawater was sampled and thoroughly analyzed chemically and for methane C isotope ratios. At Bush hill the pore fluid chemistry varies significantly over short distances as well as within some of the specific sites monitored for 440 days, and gas venting is primarily focused. The pore fluid chemistry in the tub-warm and mussel shell fields clearly documented active gas hydrate and authigenic carbonate formation during the monitoring period. The advecting fluid is depleted in sulfate, Ca Mg, and Sr and is rich in methane; at the main vent sites the fluid is methane supersaturated, thus bubble plumes form. The subsurface hydrology exhibits both

  10. Depressurization and electrical heating of hydrate sediment for gas production

    NASA Astrophysics Data System (ADS)

    Minagawa, H.

    2015-12-01

    As a part of a Japanese National hydrate research program (MH21, funded by METI), we performed a study on electrical heating of the hydrate core combined with depressurization for gas production. In-situ dissociation of natural gas hydrate is necessary for commercial recovery of natural gas from natural gas hydrate sediment. Thermal stimulation is an effective dissociation method, along with depressurization.To simulate methane gas production from methane hydrate layer, we investigated electrical heating of methane hydrate sediment. A decrease in core temperature due to the endothermic reaction of methane hydrate dissociation was suppressed and the core temperature increased between 1oC and 4oC above the control temperature with electric heating. A current density of 10A/m2 with depressurization would effectively dissociate hydrate. Therefore, depressurization and additional electrode heating of hydrate sediment saturated with electrolyte solution was confirmed to enable higher gas production from sediment with less electric power.

  11. Properties of equilibrium carbon dioxide hydrate in porous medium

    NASA Astrophysics Data System (ADS)

    Voronov, V. P.; Gorodetskii, E. E.; Podnek, V. E.; Grigoriev, B. A.

    2016-09-01

    Specific heat capacity, dissociation heat and hydration number of carbon dioxide hydrate in porous medium are determined by adiabatic calorimetry method. The measurements were carried out in the temperature range 250-290 K and in pressure range 1-5 MPa. The measured specific heat of the hydrate is approximately 2.7 J/(g K), which is significantly larger than the specific heat of methane hydrate. In particular, at heating, larger value of the specific heat of carbon dioxide hydrate is a result of gas emission from the hydrate. The hydration number at the hydrate-gas coexistence changes from 6.2 to 6.9. The dissociation heat of carbon dioxide hydrate varies from the 55 kJ/mol near the upper quadruple point to the 57 kJ/mol near the lower quadruple point.

  12. Thermodynamic properties of methane hydrate in quartz powder.

    PubMed

    Voronov, Vitaly P; Gorodetskii, Evgeny E; Safonov, Sergey S

    2007-10-01

    Using the experimental method of precision adiabatic calorimetry, the thermodynamic (equilibrium) properties of methane hydrate in quartz sand with a grain size of 90-100 microm have been studied in the temperature range of 260-290 K and at pressures up to 10 MPa. The equilibrium curves for the water-methane hydrate-gas and ice-methane hydrate-gas transitions, hydration number, latent heat of hydrate decomposition along the equilibrium three-phase curves, and the specific heat capacity of the hydrate have been obtained. It has been experimentally shown that the equilibrium three-phase curves of the methane hydrate in porous media are shifted to the lower temperature and high pressure with respect to the equilibrium curves of the bulk hydrate. In these experiments, we have found that the specific heat capacity of the hydrate, within the accuracy of our measurements, coincides with the heat capacity of ice. The latent heat of the hydrate dissociation for the ice-hydrate-gas transition is equal to 143 +/- 10 J/g, whereas, for the transition from hydrate to water and gas, the latent heat is 415 +/- 15 J/g. The hydration number has been evaluated in the different hydrate conditions and has been found to be equal to n = 6.16 +/- 0.06. In addition, the influence of the water saturation of the porous media and its distribution over the porous space on the measured parameters has been experimentally studied.

  13. The Hydration Structure at Yttria-Stabilized Cubic Zirconia (110)-Water Interface with Sub-Ångström Resolution

    NASA Astrophysics Data System (ADS)

    Hou, Binyang; Kim, Seunghyun; Kim, Taeho; Kim, Jongjin; Hong, Seungbum; Bahn, Chi Bum; Park, Changyong; Kim, Ji Hyun

    2016-06-01

    The interfacial hydration structure of yttria-stabilized cubic zirconia (110) surface in contact with water was determined with ~0.5 Å resolution by high-resolution X-ray reflectivity measurement. The terminal layer shows a reduced electron density compared to the following substrate lattice layers, which indicates there are additional defects generated by metal depletion as well as intrinsic oxygen vacancies, both of which are apparently filled by water species. Above this top surface layer, two additional adsorbed layers are observed forming a characteristic interfacial hydration structure. The first adsorbed layer shows abnormally high density as pure water and likely includes metal species, whereas the second layer consists of pure water. The observed interfacial hydration structure seems responsible for local equilibration of the defective surface in water and eventually regulating the long-term degradation processes. The multitude of water interactions with the zirconia surface results in the complex but highly ordered interfacial structure constituting the reaction front.

  14. Guest Molecule Exchange Kinetics for the 2012 Ignik Sikumi Gas Hydrate Field Trial

    SciTech Connect

    White, Mark D.; Lee, Won Suk

    2014-05-14

    A commercially viable technology for producing methane from natural gas hydrate reservoirs remains elusive. Short-term depressurization field tests have demonstrated the potential for producing natural gas via dissociation of the clathrate structure, but the long-term performance of the depressurization technology ultimately requires a heat source to sustain the dissociation. A decade of laboratory experiments and theoretical studies have demonstrated the exchange of pure CO2 and N2-CO2 mixtures with CH4 in sI gas hydrates, yielding critical information about molecular mechanisms, recoveries, and exchange kinetics. Findings indicated the potential for producing natural gas with little to no production of water and rapid exchange kinetics, generating sufficient interest in the guest-molecule exchange technology for a field test. In 2012 the U.S. DOE/NETL, ConocoPhillips Company, and Japan Oil, Gas and Metals National Corporation jointly sponsored the first field trial of injecting a mixture of N2-CO2 into a CH4-hydrate bearing formation beneath the permafrost on the Alaska North Slope. Known as the Ignik Sikumi #1 Gas Hydrate Field Trial, this experiment involved three stages: 1) the injection of a N2-CO2 mixture into a targeted hydrate-bearing layer, 2) a 4-day pressurized soaking period, and 3) a sustained depressurization and fluid production period. Data collected during the three stages of the field trial were made available after an extensive quality check. These data included continuous temperature and pressure logs, injected and recovered fluid compositions and volumes. The Ignik Sikumi #1 data set is extensive, but contains no direct evidence of the guest-molecule exchange process. This investigation is directed at using numerical simulation to provide an interpretation of the collected data. A numerical simulator, STOMP-HYDT-KE, was recently completed that solves conservation equations for energy, water, mobile fluid guest molecules, and hydrate guest

  15. Hydration sequence of swelling clays: evolutions of specific surface area and hydration energy.

    PubMed

    Salles, Fabrice; Douillard, Jean-Marc; Denoyel, Renaud; Bildstein, Olivier; Jullien, Michel; Beurroies, Isabelle; Van Damme, Henri

    2009-05-15

    In order to identify the key steps and the driving force for the hydration process of swelling clays, the water adsorption isotherms and enthalpies were measured on monoionic montmorillonite samples saturated with alkali or calcium ions, and on bi-ionic samples saturated with a sodium-calcium mixture. The specific surface area evolution along the hydration process was determined using a recent interpretation of the experimental adsorption isotherms of swelling solids. Results are interpreted in structural terms. Compared with additional data from sample-controlled thermal analysis (SCTA), the results confirm experimentally that the hydration of Li- and Na-montmorillonite is mainly a cation-controlled process, in contrast with the hydration of Cs samples in which the cation contribution to hydration is negligible, as we have already demonstrated using electrostatic calculations or conductivity measurements. PMID:19303602

  16. High-Altitude Hydration System

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott E.; Orndoff, Evelyne; Bue, Grant C.; Schaefbauer, Mark E.; Urban, Kase

    2010-01-01

    Three methods are being developed for keeping water from freezing during high-altitude climbs so that mountaineers can remain hydrated. Three strategies have been developed. At the time of this reporting two needed to be tested in the field and one was conceptual. The first method is Passive Thermal Control Using Aerogels. This involves mounting the fluid reservoir of the climber s canteen to an inner layer of clothing for better heat retention. For the field test, bottles were mounted to the inner fleece layer of clothing, and then aerogel insulation was placed on the outside of the bottle, and circumferentially around the drink straw. When climbers need to drink, they can pull up the insulated straw from underneath the down suit, take a sip, and then put it back into the relative warmth of the suit. For the field test, a data logger assessed the temperatures of the water reservoir, as well as near the tip of the drink straw. The second method is Passive Thermal Control with Copper-Shielded Drink Straw and Aerogels, also mounted to inner layers of clothing for better heat retention. Braided wire emanates from the inside of the fleece jacket layer, and continues up and around the drink straw in order to use body heat to keep the system-critical drink straw warm enough to keep water in the liquid state. For the field test, a data logger will be used to compare this with the above concept. The third, and still conceptual, method is Active Thermal Control with Microcontroller. If the above methods do not work, microcontrollers and tape heaters have been identified that could keep the drink straw warm even under extremely cold conditions. Power requirements are not yet determined because the thermal environment inside the down suit relative to the external environment has not been established. A data logger will be used to track both the external and internal temperatures of the suit on a summit day.

  17. Secondary iron sulphates in AMD: a minerochemical analysis on jarosite supporting the valorization of its geoenvironmental contribution

    NASA Astrophysics Data System (ADS)

    Silva, Teresa; Figueiredo, Maria-Ondina

    2010-05-01

    Currently, iron sulphates formed in abandoned sulphide-ore mines have a very negative connotation within acid mine drainage (AMD) because in general these secondary hydroxilated and/or hydrated minerals concentrate a large span of toxic elements. However, this apparently penalizing feature may occasionally turn out to be a positive contribution, once sequestering such elements under the form of stable minerals significantly reduces their spread in soils and rivers, as occurs for jarosite in what concerns lead. The application of an exergetic analysis to resources consumption and sustainability assessment [1] provides a means of evaluating the degradation of mineral resources on Earth and a life cycle assessment (LCA) recently performed on some secondary iron sulphates has emphasized their exergetic contribution [2]. With the purpose of further exploring this positive aspect, and focusing on jarosite, a synopsis is presented on the structural features and geochemical tendencies of secondary iron sulphates liable of being exploited to promote their possible role. Jarosites (s.l.) - with general formula AB3(OH)6(SO4)2, where A is mainly K+, Na+, plus minor Ag+, Tl+, NH4+, Pb2+, Bi3+, and B is essentially Fe3+ (jarosite s.s.) or Al3+ (alunite) - have a trigonal crystal structure [3] and display Kagomé-type layers of corner-sharing B octahedra, [Fe/AlO2(OH)4], that give rise to unique magnetic properties [4]; the large cation A stays in pseudo-icosahedral coordination by 6 O-atoms from [SO4] tetrahedra and 6 hydroxyls shared with A octahedra [5]. A synopsis is presented on the crystal-chemistry and geochemical tendencies of jarosite and the geochemistry of sediments in the abandoned mine of S. Domingos (southern Portugal, Iberian Pyrite Belt of polymetallic sulphide ores), is briefly described to illustrate the positive environmental role of jarosite as energy-saver within the particularly aggressive environment of abandoned sulphide-ore mines. [1] B. de Meester et al

  18. Ab initio molecular dynamics calculations of ion hydration free energies

    SciTech Connect

    Leung, Kevin; Rempe, Susan B.; Lilienfeld, O. Anatole von

    2009-05-28

    We apply ab initio molecular dynamics (AIMD) methods in conjunction with the thermodynamic integration or '{lambda}-path' technique to compute the intrinsic hydration free energies of Li{sup +}, Cl{sup -}, and Ag{sup +} ions. Using the Perdew-Burke-Ernzerhof functional, adapting methods developed for classical force field applications, and with consistent assumptions about surface potential ({phi}) contributions, we obtain absolute AIMD hydration free energies ({Delta}G{sub hyd}) within a few kcal/mol, or better than 4%, of Tissandier et al.'s [J. Phys. Chem. A 102, 7787 (1998)] experimental values augmented with the SPC/E water model {phi} predictions. The sums of Li{sup +}/Cl{sup -} and Ag{sup +}/Cl{sup -} AIMD {Delta}G{sub hyd}, which are not affected by surface potentials, are within 2.6% and 1.2 % of experimental values, respectively. We also report the free energy changes associated with the transition metal ion redox reaction Ag{sup +}+Ni{sup +}{yields}Ag+Ni{sup 2+} in water. The predictions for this reaction suggest that existing estimates of {Delta}G{sub hyd} for unstable radiolysis intermediates such as Ni{sup +} may need to be extensively revised.

  19. Heparan sulphate as a regulator of leukocyte recruitment in inflammation.

    PubMed

    Kumar, Archana V; Katakam, Sampath K; Urbanowitz, Ann-Kathrin; Gotte, Martin

    2015-01-01

    A key event in inflammatory disease is the transendothelial recruitment of leukocytes from the circulation to the site of inflammation. Intense research in the past decades indicates that the polyanionic carbohydrate heparan sulphate (HS) modulates multiple steps in the leukocyte recruitment cascade. Leukocyte recruitment is initiated by endothelial cell activation and presentation of chemokines to rolling leukocytes, which, via integrin activation, results in adhesion and diapedesis through the vessel wall. Heparan sulfate proteoglycans (HSPGs) immobilize the chemokines on the luminal endothelial cells, rendering them more robust against mechanical or hydrodynamic perturbations. During inflammation, endothelial HSPGs serve as ligands to L-selectin on leukocytes, transport chemokines in a basolateral to apical direction across the endothelium, and present chemokines at the luminal surface of the endothelium to circulating cells. HSPGs also promote chemokine oligomerization, which influences chemokine receptor signaling. Furthermore, proteoglycans of the syndecan family are involved in modulating integrin-mediated tight adhesion of leukocytes to the endothelium. Creation of a chemokine gradient by a localized chemokine release influences the speed of leukocyte recruitment from the blood to the tissue by attracting crawling neutrophils to optimal sites for transmigration. The directionality of intraluminal crawling is thought to be influenced by both mechanotactic and haptotactic signals, which are modulated by HS-dependent signaling processes. Finally, diapedesis is influenced by HS regarding transendothelial chemokine gradient formation and integrin- CAM interactions, and further enhanced by heparanase-mediated degradation of the endothelial basement membrane. Overall, the multifunctional role of HS in inflammation marks it as a potential target of glycan-centered therapeutic approaches.

  20. Correlations between stream sulphate and regional SO2 emissions

    USGS Publications Warehouse

    Smith, R.A.; Alexander, R.B.

    1986-01-01

    The relationship between atmospheric SO2 emissions and stream and lake acidification has been difficult to quantify, largely because of the limitations of sulphur deposition measurements. Precipitation sulphate (SO4) records are mostly <5 yr in length and do not account for dry sulphur deposition. Moreover, a variable fraction of wet- and dry-deposited sulphur is retained in soils and vegetation and does not contribute to the acidity of aquatic systems. We have compared annual SO2 emissions for the eastern United States from 1976 to 1980 with stream SO4 measurements from fifteen predominantly undeveloped watersheds. We find that the two forms of sulphur are strongly correlated on a regional basis and that streams in the southeastern United States (SE) receive a smaller fraction (on average, 16%, compared with 24%) of regional sulphur emissions than do streams in the northeastern United States (NE). In addition to providing direct empirical evidence of a relationship between sulphur emissions and aquatic chemistry, these results suggest that there are significant regional differences in the fraction of deposited sulphur retained in basin soils and vegetation.The relationship between atmospheric SO//2 emissions and stream and lake acidification has been difficult to quantify, largely because of the limitations of sulphur deposition measurements. The authors have compared annual SO//2 emissions for the eastern United States from 1967 to 1980 with stream SO//4 measurements from fifteen predominantly undeveloped watersheds. They found that both the wet - and dry-deposited forms of sulphur are strongly correlated on a regional basis and that streams in the southeastern United States receive a smaller fraction (on average, 16%, compared with 24%) of regional sulphur emissions than do streams in the northeastern United States. In addition to providing direct empirical evidence of a relationship between sulphur emissions and aquatic chemistry, these results suggest that

  1. The geology of aluminium phosphates and sulphates of the alunite group minerals: a review

    NASA Astrophysics Data System (ADS)

    Dill, Harald G.

    2001-03-01

    Aluminium phosphates and sulphates of the alunite supergroup (APS minerals) occur in a wide range of environments of formation covering the metamorphic, igneous and sedimentary realms. Supergene processes, including mineral dressing and dumping when sulphide ores are mined, as well as hypogene alteration are also responsible for the precipitation of APS minerals. In these environments, complex solid solution series (s.s.s.) can form. The general formula of these alunite minerals is AB 3 (XO 4) 2(OH) 6, where A is a large cation (Na, U, K, Ag, NH 4, Pb, Ca, Ba, Sr, REE). B sites are occupied by cations of the elements Al, Fe, Cu and Zn. In nature, the anion (XO 4) x- is dominated by P and S. Mineral dressing and identification of APS minerals often needs a combination of highly sophisticated measures including Atterberg settling methods, XRD, DTA, TGA, TEM-EDX, SEM, EMPA and XRF. In sedimentary rocks APS minerals occur in various rocks and environments of deposition: calcareous, phosphorite-bearing, argillaceous-carbonaceous, arenaceous, coal-bearing environments, in soils and paleosols, in saprolite (bauxites, laterites) and in calcareous-argillaceous sequences hosting Carlin-type SHDG deposits. In igneous rocks, APS minerals may be encountered mainly in acidic through intermediate pyroclastic, volcanic and subvolcanic rocks. They occur in barren volcanic rocks and porphyry-type intrusions that have sparked epithermal Au-Ag-base metal deposits, Au-Sb mineralization, APS-bearing argillite and alunite deposits in their immediate surroundings. Granitic and pegmatitic rocks are rarely host of supergene APS mineralization. During low-grade stage regional metamorphism, peraluminous parent rocks originating from a sedimentary or igneous protolith may also give rise to APS mineralization. Peraluminous parent rocks enriched in S and/or P are a prerequisite for the formation of APS minerals that are stable up to a temperature of 400°C at moderately high fluid pressure of up

  2. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    SciTech Connect

    Richard Sigal; Kent Newsham; Thomas Williams; Barry Freifeld; Timothy Kneafsey; Carl Sondergeld; Shandra Rai; Jonathan Kwan; Stephen Kirby; Robert Kleinberg; Doug Griffin

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. The work scope drilled and cored a well The Hot Ice No. 1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report. The Hot Ice No. 1 well was drilled from the surface to a measured depth of 2300 ft. There was almost 100% core recovery from the bottom of surface casing at 107 ft to total depth. Based on the best estimate of the bottom of the methane hydrate stability zone (which used new data obtained from Hot Ice No. 1 and new analysis of data from adjacent wells), core was recovered over its complete range. Approximately 580 ft of porous, mostly frozen, sandstone and 155 of conglomerate were recovered in the Ugnu Formation and approximately 215 ft of porous sandstone were recovered in the West Sak Formation. There were gas shows in the bottom

  3. Complex admixtures of clathrate hydrates in a water desalination method

    DOEpatents

    Simmons, Blake A.; Bradshaw, Robert W.; Dedrick, Daniel E.; Anderson, David W.

    2009-07-14

    Disclosed is a method that achieves water desalination by utilizing and optimizing clathrate hydrate phenomena. Clathrate hydrates are crystalline compounds of gas and water that desalinate water by excluding salt molecules during crystallization. Contacting a hydrate forming gaseous species with water will spontaneously form hydrates at specific temperatures and pressures through the extraction of water molecules from the bulk phase followed by crystallite nucleation. Subsequent dissociation of pure hydrates yields fresh water and, if operated correctly, allows the hydrate-forming gas to be efficiently recycled into the process stream.

  4. Subterahertz characterization of ethanol hydration layers by microfluidic system

    NASA Astrophysics Data System (ADS)

    Laurette, S.; Treizebre, A.; Affouard, F.; Bocquet, B.

    2010-09-01

    Characterizations of ethanol hydration layers are examined through subterahertz spectroscopy of water/ethanol mixtures by using a microfluidic system. A three-component model is used to explain measurements discrepancies with the Lambert-Beer law and to determine ethanol hydration shell absorption. Moreover, the hydration shell distribution is compared with molecular dynamics simulations with a good agreement. Ethanol hydration number is then computed and it can quickly characterize only the first water hydration layer or the whole hydration shell, depending on the chosen extraction model.

  5. Hydrate problems in pipelines: A study from Norwegian continental waters

    SciTech Connect

    Lysne, D.; Larsen, R.; Lund, A.; Thomsen, A.K.

    1995-12-31

    This study was undertaken by the Norwegian Petroleum Directorate and SINTEF to identify hydrate problems occurring in pipelines on the Norwegian continental shelf. A brief review of hydrate dissociation theory is given. Three major techniques for hydrate removal are discussed, as well as hazards related to hydrate plug removal. Questionnaire answers from 15 companies operating in Norwegian waters show three specific occurrences of hydrate plugs in the North Sea. Problems from other geographical areas are also discussed. Hydrate problems are reported for a wide variety of pipe lengths, diameters, profiles, insulations characteristics and fluids. Most problems occur during normal operation.

  6. Development of hydrate risk quantification in oil and gas production

    NASA Astrophysics Data System (ADS)

    Chaudhari, Piyush N.

    Subsea flowlines that transport hydrocarbons from wellhead to the processing facility face issues from solid deposits such as hydrates, waxes, asphaltenes, etc. The solid deposits not only affect the production but also pose a safety concern; thus, flow assurance is significantly important in designing and operating subsea oil and gas production. In most subsea oil and gas operations, gas hydrates form at high pressure and low temperature conditions, causing the risk of plugging flowlines, with a undesirable impact on production. Over the years, the oil and gas industry has shifted their perspective from hydrate avoidance to hydrate management given several parameters such as production facility, production chemistry, economic and environmental concerns. Thus, understanding the level of hydrate risk associated with subsea flowlines is an important in developing efficient hydrate management techniques. In the past, hydrate formation models were developed for various flow-systems (e.g., oil dominated, water dominated, and gas dominated) present in the oil and gas production. The objective of this research is to extend the application of the present hydrate prediction models for assessing the hydrate risk associated with subsea flowlines that are prone to hydrate formation. It involves a novel approach for developing quantitative hydrate risk models based on the conceptual models built from the qualitative knowledge obtained from experimental studies. A comprehensive hydrate risk model, that ranks the hydrate risk associated with the subsea production system as a function of time, hydrates, and several other parameters, which account for inertial, viscous, interfacial forces acting on the flow-system, is developed for oil dominated and condensate systems. The hydrate plugging risk for water dominated systems is successfully modeled using The Colorado School of Mines Hydrate Flow Assurance Tool (CSMHyFAST). It is found that CSMHyFAST can be used as a screening tool in

  7. Study on propane-butane gas storage by hydrate technology

    NASA Astrophysics Data System (ADS)

    Hamidi, Nurkholis; Wijayanti, Widya; Widhiyanuriyawan, Denny

    2016-03-01

    Different technology has been applied to store and transport gas fuel. In this work the storage of gas mixture of propane-butane by hydrate technology was studied. The investigation was done on the effect of crystallizer rotation speed on the formation of propane-butane hydrate. The hydrates were formed using crystallizer with rotation speed of 100, 200, and 300 rpm. The formation of gas hydrates was done at initial pressure of 3 bar and temperature of 274K. The results indicated that the higher rotation speed was found to increase the formation rate of propane-butane hydrate and improve the hydrates stability.

  8. Aluminium-phosphate-sulphate minerals as markers of sustained acidic conditions during the Permian-Triassic transition in E Iberia.

    NASA Astrophysics Data System (ADS)

    Borruel-Abadía, Violeta; Belén Galán-Abellán, Ana; Barrenechea, José F.; De la Horra, Raúl; Luque, Francisco Javier; Alonso-Azcárate, Jacinto; López-Gómez, José

    2016-04-01

    Strontium-rich hydrated Aluminium phosphate-sulphate (APS) minerals are markers of an acidic formation environment due to their precipitation at low pH conditions. However, their small size (0.5-6 μm), low concentrations, and optical properties represent the main problems to quantify these minerals. This study provides quantitative data on APS mineral concentrations for the Late Permian and Early-Middle Triassic in different continental sections of East Iberia. By quantifying APS minerals useful insight can be obtained into the environmental conditions that prevailed during the biotic crisis of the PTB and during the later recovery of life at the end of the Early Triassic. For that, a quantification method based on element mapping of randomly selected areas of thin sections on the electron microprobe is proposed, with relative errors ranging from 5.6% to 11.7%. The results are considered on a detailed petrographic, sedimentological, and palaeontological framework, and compared with other geochemical. Thus, in the first sedimentary record after the Permian-Triassic boundary (Olenekian), it has been possible to correlate relatively high concentration levels of APS minerals with the lack of signs of living organisms. Our findings suggest a long period of sustained acidic conditions followed by an environmental change that permitted the recovery of life, as reflected by lower APS mineral contents detected at the end of the Spathian and the first presence of bioturbation, paleosols, footprints, and plant remains. Early Anisian acidic episodes were much more sporadic than those during the Olenekian deposition, in which APS mineral concentrations were an order of magnitude higher. This fact would indicate punctual acidic conditions still during the beginning of the Anisian. Based on these results, this method is proposed as a tool for addressing environmental changes that took place during the Permian-Triassic transition in continental environments.

  9. Hydraulic and Mechanical Effects from Gas Hydrate Conversion and Secondary Gas Hydrate Formation during Injection of CO2 into CH4-Hydrate-Bearing Sediments

    NASA Astrophysics Data System (ADS)

    Bigalke, N.; Deusner, C.; Kossel, E.; Schicks, J. M.; Spangenberg, E.; Priegnitz, M.; Heeschen, K. U.; Abendroth, S.; Thaler, J.; Haeckel, M.

    2014-12-01

    The injection of CO2 into CH4-hydrate-bearing sediments has the potential to drive natural gas production and simultaneously sequester CO2 by hydrate conversion. The process aims at maintaining the in situ hydrate saturation and structure and causing limited impact on soil hydraulic properties and geomechanical stability. However, to increase hydrate conversion yields and rates it must potentially be assisted by thermal stimulation or depressurization. Further, secondary formation of CO2-rich hydrates from pore water and injected CO2 enhances hydrate conversion and CH4 production yields [1]. Technical stimulation and secondary hydrate formation add significant complexity to the bulk conversion process resulting in spatial and temporal effects on hydraulic and geomechanical properties that cannot be predicted by current reservoir simulation codes. In a combined experimental and numerical approach, it is our objective to elucidate both hydraulic and mechanical effects of CO2 injection and CH4-CO2-hydrate conversion in CH4-hydrate bearing soils. For the experimental approach we used various high-pressure flow-through systems equipped with different online and in situ monitoring tools (e.g. Raman microscopy, MRI and ERT). One particular focus was the design of triaxial cell experimental systems, which enable us to study sample behavior even during large deformations and particle flow. We present results from various flow-through high-pressure experimental studies on different scales, which indicate that hydraulic and geomechanical properties of hydrate-bearing sediments are drastically altered during and after injection of CO2. We discuss the results in light of the competing processes of hydrate dissociation, hydrate conversion and secondary hydrate formation. Our results will also contribute to the understanding of effects of temperature and pressure changes leading to dissociation of gas hydrates in ocean and permafrost systems. [1] Deusner C, Bigalke N, Kossel E

  10. Novel hydrogen hydrate structures under pressure.

    PubMed

    Qian, Guang-Rui; Lyakhov, Andriy O; Zhu, Qiang; Oganov, Artem R; Dong, Xiao

    2014-01-01

    Gas hydrates are systems of prime importance. In particular, hydrogen hydrates are potential materials of icy satellites and comets, and may be used for hydrogen storage. We explore the H₂O-H₂ system at pressures in the range 0-100 GPa with ab initio variable-composition evolutionary simulations. According to our calculation and previous experiments, the H₂O-H₂ system undergoes a series of transformations with pressure, and adopts the known open-network clathrate structures (sII, C₀), dense "filled ice" structures (C₁, C₂) and two novel hydrate phases. One of these is based on the hexagonal ice framework and has the same H₂O:H₂ ratio (2:1) as the C₀ phase at low pressures and similar enthalpy (we name this phase Ih-C₀). The other newly predicted hydrate phase has a 1:2 H₂O:H₂ ratio and structure based on cubic ice. This phase (which we name C₃) is predicted to be thermodynamically stable above 38 GPa when including van der Waals interactions and zero-point vibrational energy, and explains previously mysterious experimental X-ray diffraction and Raman measurements. This is the hydrogen-richest hydrate and this phase has a remarkable gravimetric density (18 wt.%) of easily extractable hydrogen.

  11. An extended dynamical hydration shell around proteins.

    PubMed

    Ebbinghaus, Simon; Kim, Seung Joong; Heyden, Matthias; Yu, Xin; Heugen, Udo; Gruebele, Martin; Leitner, David M; Havenith, Martina

    2007-12-26

    The focus in protein folding has been very much on the protein backbone and sidechains. However, hydration waters make comparable contributions to the structure and energy of proteins. The coupling between fast hydration dynamics and protein dynamics is considered to play an important role in protein folding. Fundamental questions of protein hydration include, how far out into the solvent does the influence of the biomolecule reach, how is the water affected, and how are the properties of the hydration water influenced by the separation between protein molecules in solution? We show here that Terahertz spectroscopy directly probes such solvation dynamics around proteins, and determines the width of the dynamical hydration layer. We also investigate the dependence of solvation dynamics on protein concentration. We observe an unexpected nonmonotonic trend in the measured terahertz absorbance of the five helix bundle protein lambda(6-85)* as a function of the protein: water molar ratio. The trend can be explained by overlapping solvation layers around the proteins. Molecular dynamics simulations indicate water dynamics in the solvation layer around one protein to be distinct from bulk water out to approximately 10 A. At higher protein concentrations such that solvation layers overlap, the calculated absorption spectrum varies nonmonotonically, qualitatively consistent with the experimental observations. The experimental data suggest an influence on the correlated water network motion beyond 20 A, greater than the pure structural correlation length usually observed.

  12. Novel hydrogen hydrate structures under pressure.

    PubMed

    Qian, Guang-Rui; Lyakhov, Andriy O; Zhu, Qiang; Oganov, Artem R; Dong, Xiao

    2014-01-01

    Gas hydrates are systems of prime importance. In particular, hydrogen hydrates are potential materials of icy satellites and comets, and may be used for hydrogen storage. We explore the H₂O-H₂ system at pressures in the range 0-100 GPa with ab initio variable-composition evolutionary simulations. According to our calculation and previous experiments, the H₂O-H₂ system undergoes a series of transformations with pressure, and adopts the known open-network clathrate structures (sII, C₀), dense "filled ice" structures (C₁, C₂) and two novel hydrate phases. One of these is based on the hexagonal ice framework and has the same H₂O:H₂ ratio (2:1) as the C₀ phase at low pressures and similar enthalpy (we name this phase Ih-C₀). The other newly predicted hydrate phase has a 1:2 H₂O:H₂ ratio and structure based on cubic ice. This phase (which we name C₃) is predicted to be thermodynamically stable above 38 GPa when including van der Waals interactions and zero-point vibrational energy, and explains previously mysterious experimental X-ray diffraction and Raman measurements. This is the hydrogen-richest hydrate and this phase has a remarkable gravimetric density (18 wt.%) of easily extractable hydrogen. PMID:25001502

  13. Fragmentation and hydration of tektites and microtektites

    USGS Publications Warehouse

    Glass, B.P.; Muenow, D.W.; Bohor, B.F.; Meeker, G.P.

    1997-01-01

    An examination of data collected over the last 30 years indicates that the percent of glass fragments vs. whole splash forms in the Cenozoic microtektite strewn fields increases towards the source crater (or source region). We propose that this is due to thermal stress produced when tektites and larger microtektites fall into water near the source crater while still relatively hot (>1150 ??C). We also find evidence (low major oxide totals, frothing when melted) for hydration of most of the North American tektite fragments and microtektites found in marine sediments. High-temperature mass spectrometry indicates that these tektite fragments and microtektites contain up to 3.8 wt% H2O. The H2O-release behavior during the high-temperature mass-spectrometric analysis, plus high Cl abundances (???0.05 wt%), indicate that the North. American tektite fragments and microtektites were hydrated in the marine environment (i.e., the H2O was not trapped solely on quenching from a melt). The younger Ivory Coast and Australasian microtektites do not exhibit much evidence of hydration (at least not in excess of 0.5 wt% H2O); this suggests that the degree of hydration increases with age. In addition, we find that some glass spherules (with 65 wt% SiO2 can undergo simple hydration in the marine environment, while impact glasses (with <65 wt% SiO2) can also undergo palagonitization.

  14. Interfacial phenomena in gas hydrate systems.

    PubMed

    Aman, Zachary M; Koh, Carolyn A

    2016-03-21

    Gas hydrates are crystalline inclusion compounds, where molecular cages of water trap lighter species under specific thermodynamic conditions. Hydrates play an essential role in global energy systems, as both a hinderance when formed in traditional fuel production and a substantial resource when formed by nature. In both traditional and unconventional fuel production, hydrates share interfaces with a tremendous diversity of materials, including hydrocarbons, aqueous solutions, and inorganic solids. This article presents a state-of-the-art understanding of hydrate interfacial thermodynamics and growth kinetics, and the physiochemical controls that may be exerted on both. Specific attention is paid to the molecular structure and interactions of water, guest molecules, and hetero-molecules (e.g., surfactants) near the interface. Gas hydrate nucleation and growth mechanics are also presented, based on studies using a combination of molecular modeling, vibrational spectroscopy, and X-ray and neutron diffraction. The fundamental physical and chemical knowledge and methods presented in this review may be of value in probing parallel systems of crystal growth in solid inclusion compounds, crystal growth modifiers, emulsion stabilization, and reactive particle flow in solid slurries. PMID:26781172

  15. The efficiacy of bismuth subnitrate against genotoxicity and oxidative stress induced by aluminum sulphate.

    PubMed

    Turkez, Hasan; Geyikoglu, Fatime

    2011-03-01

    Aluminum (Al) is commonly used in industrial processes and drugs and is thought to induce erythrocytes damage via activation of oxidative stress. Recently, bismuth (Bi)-containing drugs are used in the treatment of various diseases. However, uncertain effects of Bi in blood tissue may participate in the therapeutic efficacy of Bi compounds as related to metals. Hence, this study aimed to determine the roles on human blood cells of the various concentrations of aluminum sulphate (Al(2)(SO(4))(3)) and bismuth subnitrate (BSN), separate and together. With this aim, oxidative status was assessed on erythrocytes by measuring following oxidative stress markers: reduced glutathione (GSH), superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G-6-PDH) and catalase (CAT). Two chemicals were tested for their ability to induce cytogenetic change in human lymphocytes using assays for chromosome aberrations (CAs) and sister chromatid exchanges (SCEs). Our results showed that high dose of Al(2)(SO(4))(3) (20 µg/mL) caused oxidative stress and increased CA and SCE frequencies. Whereas, BSN doses did not change CA and SCE rates. Moreover, it led to changes of antioxidant capacity at different concentrations. After concomitant treatment with Al(2)(SO(4))(3) and BSN, the effects of BSN doses were different on enzyme activities and decreased the genotoxic damage. However, the high dose of BSN and Al(2)(SO(4))(3) was shown to enhance the frequencies of CAs and SCEs in a synergistic manner. In conclusion, BSN could be effective in the protection against the blood toxicity of Al(2)(SO(4))(3).

  16. Rust in the Apollo 16 rocks. [hydration and oxidation processes in lunar environment

    NASA Technical Reports Server (NTRS)

    Taylor, L. A.; Mao, H. K.; Bell, P. M.

    1973-01-01

    Apollo 16 samples of all four rock types and from all stations contain evidence for hydration and oxidation - i.e., the presence of hydrated iron oxide, probably goethite. Rock 66095 contains native FeNi grains with a characteristic intergrowth of schreibersite and, to lesser extents, of cohenite. Troilite also contains sphalerite. The goethite contains 1.5-4.6 wt.% chlorine and occurs mainly on the edges of FeNi metal, causing a rust color in the cracks and space around the native metal grains, which also contain abundant chlorine. This observation suggests the presence of lawrencite (FeCl2), a phase that deliquesces and oxidizes very rapidly upon exposure to water or to a moist atmosphere.

  17. Stability evaluation of hydrate-bearing sediments during thermally-driven hydrate dissociation

    NASA Astrophysics Data System (ADS)

    Kwon, T.; Cho, G.; Santamarina, J.; Kim, H.; Lee, J.

    2009-12-01

    Hydrate-bearing sediments may destabilize spontaneously as part of geological processes, unavoidably during petroleum drilling/production operations, or intentionally as part of gas extraction from the hydrate itself. In all cases, high pore fluid pressure generation is anticipated during hydrate dissociation. This study examined how thermal changes destabilize gas hydrate-bearing sediments. First, an analytical formulation was derived for predicting fluid pressure evolution in hydrate-bearing sediments subjected to thermal stimulation without mass transfer. The formulation captures the self-preservation behavior, calculates the hydrate and free gas quantities during dissociation, considering effective stress-controlled sediment compressibility and gas solubility in aqueous phase. Pore fluid pressure generation is proportional to the initial hydrate fraction and the sediment bulk stiffness; is inversely proportional to the initial gas fraction and gas solubility; and is limited by changes in effective stress that cause the failure of the sediment. Second, the analytical formulation for hydrate dissociation was incorporated as a user-defined function into a verified finite difference code (FLAC2D). The underlying physical processes of hydrate-bearing sediments, including hydrate dissociation, self-preservation, pore pressure evolution, gas dissolution, and sediment volume expansion, were coupled with the thermal conduction, pore fluid flow, and mechanical response of sediments. We conducted the simulations for a duration of 20 years, assuming a constant-temperature wellbore transferred heat to the surrounding hydrate-bearing sediments, resulting in dissociation of methane hydrate in the well vicinity. The model predicted dissociation-induced excess pore fluid pressures which resulted in a large volume expansion and plastic deformation of the sediments. Furthermore, when the critical stress was reached, localized shear failure of the sediment around the borehole was

  18. Gas Hydrates and Perturbed Permafrost: Can Thermokarst Lakes Leak Hydrate-Derived Methane?

    NASA Astrophysics Data System (ADS)

    Ruppel, C.; Walter, K.; Pohlman, J.; Wooller, M.

    2008-12-01

    Thermokarst lakes are common features in the continuous permafrost of Siberia, the Alaskan North Slope, and the Canadian Arctic and have been intensely studied as the loci of rapid and substantial methane flux to the atmosphere. Previous numerical modeling has constrained the conditions under which deep thermokarst lakes can develop organic-rich thaw bulbs (talik) tens of meters thick, and seismic surveys have imaged thaw bulbs more than 75 m thick beneath some thermokarst lakes. Microbial processes active in talik organic material are likely the predominant source for thermokarst methane emissions, although coalbed methane and methane associated with conventional hydrocarbons may contribute in some geologic settings. Here we evaluate the possibility that another source--methane released from dissociating gas hydrate--could contribute to methane emissions from these lakes. Temperatures within and beneath thermokarst lakes are significantly warmer than those in surrounding permafrost, and these relatively warm conditions can persist to depths several times greater than the thickness of the thaw bulb. For a 95-m-thick thaw bulb and a geothermal gradient consistent with the regional top of gas hydrate stability at ~200 m depth, the warmer temperatures beneath a thermokarst lake could lead to destabilization of up to 75 m of gas hydrate. Arguably, the presence of gas hydrate near the top of the stability zone in permafrost regions has not yet been observed. Nonetheless, the potential dissociation of such relatively shallow gas hydrate and the widespread availability in terrestrial settings of high permeability conduits (e.g., faults, sandy strata) that could facilitate the migration of hydrate-derived methane to the surface render this an important topic for future investigation. The susceptibility of permafrost gas hydrate zones to thermal perturbations is in sharp contrast to the situation in conventional marine hydrate provinces. There, gas hydrate first dissociates

  19. Weight-of-evidence approach in assessment of ecotoxicological risks of acid sulphate soils in the Baltic Sea river estuaries.

    PubMed

    Wallin, Jaana; Karjalainen, Anna K; Schultz, Eija; Järvistö, Johanna; Leppänen, Matti; Vuori, Kari-Matti

    2015-03-01

    Acidity and leaching of metals from acid sulphate soils (ASSs) impair the water quality of receiving surface waters. The largest ASS areas in Europe are found in the coasts of the northern Baltic Sea. We used weight-of-evidence (WoE) approach to assess potential risks in 14 estuary sites affected by ASS in the Gulf of Finland, northern Baltic Sea. The assessment was based on exposure and effect profiles utilizing sediment and water metal concentrations and concurrent pH variation, sediment toxicity tests using the luminescent bacterium Vibrio fischeri and the midge Chironomus riparius, and the ecological status of benthic macroinvertebrate communities. Sediment metal concentrations were compared to national sediment quality criteria/guidelines, and water metal concentrations to environmental quality standards (EQSs). Hazard quotients (HQs) were established for maximum aluminium, cadmium and zinc concentrations at low pH based on applicable US EPA toxicity database. Sediment metal concentrations were clearly elevated in most of the studied estuaries. The EQS of cadmium (0.1 μg/l) was exceeded in 3 estuaries out of 14. The pH-minima were below the national threshold value (5.5) between good and satisfactory water quality in 10 estuaries. V. fischeri bioluminescence indicated toxicity of the sediments but toxic response was not observed in the C. riparius emergence test. Benthic invertebrate communities were deteriorated in 6 out of 14 sites based on the benthic invertebrate quality index. The overall ecotoxicological risk was assessed as low in five, moderate in three and high in five of the estuary sites. The risk assessment utilizing the WoE approach indicated that harmful effects of ASSs are likely to occur in the Baltic Sea river estuaries located at the ASS hotspot area.

  20. Mixing of methane and sulphate due to fluid flow in the Barbados accretionary prism

    SciTech Connect

    Laier, T. )

    1996-01-01

    Methane concentrations above background level in sulphate-containing (15 mmol/l) pore waters have been observed in the d6collement zone of the Barbados accretionary prism. The peak in methane concentration in the decollement was found at a number of sites by headspace analysis of cores retrieved during ODP Legs 110 156 at the toe of the accretionary prism. [delta][sup 13]C[sub 1] values between -22[per thousand] and -36[per thousand] indicate that methane oxidation occurs possibly due to sulphate reduction. Thus, the presence of both methane and sulphate at the same depths suggests mixing of fluids due to fluid flow. Fluid flow is also indicated by the distinct minima in chloride concentrations at the same depths. In the case of on-going methane oxidation, mixing of sulphate and methane fluids is anticipated to have occurred fairly recently. Sulphate concentration decreases only little with depth in the Pleistocene to lower Miocene sediments where TOC is very low, <0.2 %. Sulphate decreases more rapidly with depth in the Oligocene to Eocene sediments where numerous relatively thin turbidites occur. The turbidites have significantly higher TOC, 0.5-1.5 %, than the interbedded hemipelagic sediments, TOC <0.2 %. High methane concentrations were not found in any of the boreholes, but the trends in sulphate and methane in boreholes indicate that high methane concentrations exist in older sediments not reached by drilling. The decollement zone is composed of lower Miocene to upper Oligocene sediments near the toe of the prism, but deepens into stratigraphically lower sediments prism ward. Thus, methane originating from these older sediments may have been brought to shallower depths by active fluid flow in the decollement.

  1. Mixing of methane and sulphate due to fluid flow in the Barbados accretionary prism

    SciTech Connect

    Laier, T.

    1996-12-31

    Methane concentrations above background level in sulphate-containing (15 mmol/l) pore waters have been observed in the d6collement zone of the Barbados accretionary prism. The peak in methane concentration in the decollement was found at a number of sites by headspace analysis of cores retrieved during ODP Legs 110 & 156 at the toe of the accretionary prism. {delta}{sup 13}C{sub 1} values between -22{per_thousand} and -36{per_thousand} indicate that methane oxidation occurs possibly due to sulphate reduction. Thus, the presence of both methane and sulphate at the same depths suggests mixing of fluids due to fluid flow. Fluid flow is also indicated by the distinct minima in chloride concentrations at the same depths. In the case of on-going methane oxidation, mixing of sulphate and methane fluids is anticipated to have occurred fairly recently. Sulphate concentration decreases only little with depth in the Pleistocene to lower Miocene sediments where TOC is very low, <0.2 %. Sulphate decreases more rapidly with depth in the Oligocene to Eocene sediments where numerous relatively thin turbidites occur. The turbidites have significantly higher TOC, 0.5-1.5 %, than the interbedded hemipelagic sediments, TOC <0.2 %. High methane concentrations were not found in any of the boreholes, but the trends in sulphate and methane in boreholes indicate that high methane concentrations exist in older sediments not reached by drilling. The decollement zone is composed of lower Miocene to upper Oligocene sediments near the toe of the prism, but deepens into stratigraphically lower sediments prism ward. Thus, methane originating from these older sediments may have been brought to shallower depths by active fluid flow in the decollement.

  2. Effects of varying sulphate and nitrogen supply on DMSP and glycine betaine levels in Spartina anglica

    NASA Astrophysics Data System (ADS)

    Mulholland, M. M.; Otte, M. L.

    2000-08-01

    The relationship between sulphate, dimethylsulphoniopropionate (DMSP), and glycine betaine concentrations as well as the interaction with nitrogen supply in Spartina anglica Hubbard was investigated. Several studies have already shown that nitrogen affects levels of DMSP and glycine betaine in Spartina. It has further been suggested that sulphate is important to the growth of the salt marsh grass Spartina. We hypothesised that DMSP might be involved in a high sulphur requirement. It was further hypothesised that the effect of sulphate would depend on nitrogen supply. S. anglica shoots were treated with a range of nutrient solutions containing four different sulphate treatments, 0, 80, 800 or 1600 μM and two different nitrogen levels, 0 or 2 mM ammonium nitrate. Plant parts were analysed for DMSP and glycine betaine, as well as total nitrogen and total sulphur. Plants were analysed for proline as well but levels were very low or non-detectable and patterns were not consistent. Total sulphur was affected by both the nitrogen and sulphate treatments while total nitrogen was affected by the nitrogen treatments only. Sulphate had no effect on growth (leaf length or biomass), but nitrogen increased growth of S. anglica shoots. Levels of DMSP and glycine betaine were unaffected by increased sulphate supply. Nitrogen significantly decreased concentrations of DMSP and glycine betaine. However, due to increased biomass production, total amounts of DMSP and glycine betaine per plant were significantly higher in the 2 mM nitrogen treatments. The data suggest that pools of DMSP in roots and stems are more important than previously thought.

  3. Quantifying hydrate solidification front advancing using method of characteristics

    NASA Astrophysics Data System (ADS)

    You, Kehua; DiCarlo, David; Flemings, Peter B.

    2015-10-01

    We develop a one-dimensional analytical solution based on the method of characteristics to explore hydrate formation from gas injection into brine-saturated sediments within the hydrate stability zone. Our solution includes fully coupled multiphase and multicomponent flow and the associated advective transport in a homogeneous system. Our solution shows that hydrate saturation is controlled by the initial thermodynamic state of the system and changed by the gas fractional flow. Hydrate saturation in gas-rich systems can be estimated by 1-cl0/cle when Darcy flow dominates, where cl0 is the initial mass fraction of salt in brine, and cle is the mass fraction of salt in brine at three-phase (gas, liquid, and hydrate) equilibrium. Hydrate saturation is constant, gas saturation and gas flux decrease, and liquid saturation and liquid flux increase with the distance from the gas inlet to the hydrate solidification front. The total gas and liquid flux is constant from the gas inlet to the hydrate solidification front and decreases abruptly at the hydrate solidification front due to gas inclusion into the hydrate phase. The advancing velocity of the hydrate solidification front decreases with hydrate saturation at a fixed gas inflow rate. This analytical solution illuminates how hydrate is formed by gas injection (methane, CO2, ethane, propane) at both the laboratory and field scales.

  4. A Study on Solidification of Abandoned Mine Tailings with Hydrated Lime

    NASA Astrophysics Data System (ADS)

    Min, K.; Lee, H.

    2008-12-01

    Solidification is one of the stabilization processes for wastes and their components to reduce their toxicity and migration rates to surroundings. Hydrated limes were applied as cementing materials to solidify heavy metal contaminated tailings from the Geumjang mine and the solidified tailing specimens were tested for their appropriateness in accordance with the suggested test methods. In the preliminary tests for the solidified tailing specimens, all the specimens have higher uniaxial compressive strengths than 3.5kgf/cm2, the standard recommended for land reclamation solids by EPA(Environmental Protection Agency). Even in leaching tests for the solidified tailing specimens, concentrations of heavy metals such as As, Cd, Cu, Pb, and Zn were decreased significantly below the environmental warning standards in comparison with those of raw tailing samples. The optimum mixing ratio of tailings, hydrated lime, and water was determined through the preliminary tests. The solidified mixtures of mine tailings and hydrated lime through pozzolanic reaction were tested for their durability against repeated freezing and thawing processes. After repeated freezing and thawing, the uniaxial compressive strengths of all the solidified mixture specimens decreased in comparison with those before test but still higher than 3.5kgf/cm2, and concentrations of heavy metals such as As, Cd, Cu, Pb, and Zn were below the standards. Effluents in the repetitive artificial tests show pH's of 7.4 to 9.1 and concentrations of heavy metals such as As, Cd, Cu, Pb, and Zn of below 0.05ppm. Conclusively this study shows potential applicability of hydrated limes to in-situ stabilization of abandoned mine tailings.

  5. Hydration and leaching characteristics of cement pastes made from electroplating sludge

    SciTech Connect

    Chen, Ying-Liang; Ko, Ming-Sheng; Lai, Yi-Chieh; Chang, Juu-En

    2011-06-15

    The purpose of this study was to investigate the hydration and leaching characteristics of the pastes of belite-rich cements made from electroplating sludge. The compressive strength of the pastes cured for 1, 3, 7, 28, and 90 days was determined, and the condensation of silicate anions in hydrates was examined with the {sup 29}Si nuclear magnetic resonance (NMR) technology. The leachabilities of the electroplating sludge and the hardened pastes were studied with the multiple toxicity characteristic leaching procedure (MTCLP) and the tank leaching test (NEN 7345), respectively. The results showed that the electroplating sludge continued to leach heavy metals, including nickel, copper, and zinc, and posed a serious threat to the environment. The belite-rich cement made from the electroplating sludge was abundant in hydraulic {beta}-dicalcium silicate, and it performed well with regard to compressive-strength development when properly blended with ordinary Portland cements. The blended cement containing up to 40% the belite-rich cement can still satisfy the compressive-strength requirements of ASTM standards, and the pastes cured for 90 days had comparable compressive strength to an ordinary Portland cement paste. It was also found that the later hydration reaction of the blended cements was relatively more active, and high fractions of belite-rich cement increased the chain length of silicate hydrates. In addition, by converting the sludge into belite-rich cements, the heavy metals became stable in the hardened cement pastes. This study thus indicates a viable alternative approach to dealing with heavy metal bearing wastes, and the resulting products show good compressive strength and heavy-metal stability.

  6. Hydration and leaching characteristics of cement pastes made from electroplating sludge.

    PubMed

    Chen, Ying-Liang; Ko, Ming-Sheng; Lai, Yi-Chieh; Chang, Juu-En

    2011-06-01

    The purpose of this study was to investigate the hydration and leaching characteristics of the pastes of belite-rich cements made from electroplating sludge. The compressive strength of the pastes cured for 1, 3, 7, 28, and 90 days was determined, and the condensation of silicate anions in hydrates was examined with the (29)Si nuclear magnetic resonance (NMR) technology. The leachabilities of the electroplating sludge and the hardened pastes were studied with the multiple toxicity characteristic leaching procedure (MTCLP) and the tank leaching test (NEN 7345), respectively. The results showed that the electroplating sludge continued to leach heavy metals, including nickel, copper, and zinc, and posed a serious threat to the environment. The belite-rich cement made from the electroplating sludge was abundant in hydraulic β-dicalcium silicate, and it performed well with regard to compressive-strength development when properly blended with ordinary Portland cements. The blended cement containing up to 40% the belite-rich cement can still satisfy the compressive-strength requirements of ASTM standards, and the pastes cured for 90 days had comparable compressive strength to an ordinary Portland cement paste. It was also found that the later hydration reaction of the blended cements was relatively more active, and high fractions of belite-rich cement increased the chain length of silicate hydrates. In addition, by converting the sludge into belite-rich cements, the heavy metals became stable in the hardened cement pastes. This study thus indicates a viable alternative approach to dealing with heavy metal bearing wastes, and the resulting products show good compressive strength and heavy-metal stability.

  7. Methane hydrates in nature - Current knowledge and challenges

    USGS Publications Warehouse

    Collett, Timothy S.

    2014-01-01

    Recognizing the importance of methane hydrate research and the need for a coordinated effort, the United States Congress enacted the Methane Hydrate Research and Development Act of 2000. At the same time, the Ministry of International Trade and Industry in Japan launched a research program to develop plans for a methane hydrate exploratory drilling project in the Nankai Trough. India, China, the Republic of Korea, and other nations also have established large methane hydrate research and development programs. Government-funded scientific research drilling expeditions and production test studies have provided a wealth of information on the occurrence of methane hydrates in nature. Numerous studies have shown that the amount of gas stored as methane hydrates in the world may exceed the volume of known organic carbon sources. However, methane hydrates represent both a scientific and technical challenge, and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of methane hydrates in nature, (2) assessing the volume of natural gas stored within various methane hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural methane hydrates, (5) analyzing the methane hydrate role as a geohazard, (6) establishing the means to detect and characterize methane hydrate accumulations using geologic and geophysical data, and (7) establishing the thermodynamic phase equilibrium properties of methane hydrates as a function of temperature, pressure, and gas composition. The U.S. Department of Energy (DOE) and the Consortium for Ocean Leadership (COL) combined their efforts in 2012 to assess the contributions that scientific drilling has made and could continue to make to advance

  8. The microbial communities and potential greenhouse gas production in boreal acid sulphate, non-acid sulphate, and reedy sulphidic soils.

    PubMed

    Šimek, Miloslav; Virtanen, Seija; Simojoki, Asko; Chroňáková, Alica; Elhottová, Dana; Krištůfek, Václav; Yli-Halla, Markku

    2014-01-01

    Acid sulphate (AS) soils along the Baltic coasts contain significant amounts of organic carbon and nitrogen in their subsoils. The abundance, composition, and activity of microbial communities throughout the AS soil profile were analysed. The data from a drained AS soil were compared with those from a drained non-AS soil and a pristine wetland soil from the same region. Moreover, the potential production of methane, carbon dioxide, and nitrous oxide from the soils was determined under laboratory conditions. Direct microscopic counting, glucose-induced respiration (GIR), whole cell hybridisation, and extended phospholipid fatty acid (PLFA) analysis confirmed the presence of abundant microbial communities in the topsoil and also in the deepest Cg2 horizon of the AS soil. The patterns of microbial counts, biomass and activity in the profile of the AS soil and partly also in the non-AS soil therefore differed from the general tendency of gradual decreases in soil profiles. High respiration in the deepest Cg2 horizon of the AS soil (5.66 μg Cg(-1)h(-1), as compared to 2.71 μg Cg(-1)h(-1) in a top Ap horizon) is unusual but reasonable given the large amount of organic carbon in this horizon. Nitrous oxide production peaked in the BCgc horizon of the AS and in the BC horizon of the non-AS soil, but the peak value was ten-fold higher in the AS soil than in the non-AS soil (82.3 vs. 8.6 ng Ng(-1)d(-1)). The data suggest that boreal AS soils on the Baltic coast contain high microbial abundance and activity. This, together with the abundant carbon and total and mineral nitrogen in the deep layers of AS soils, may result in substantial gas production. Consequently, high GHG emissions could occur, for example, when the generally high water table is lowered because of arable farming.

  9. Method for production of hydrocarbons from hydrates

    DOEpatents

    McGuire, Patrick L.

    1984-01-01

    A method of recovering natural gas entrapped in frozen subsurface gas hydrate formations in arctic regions. A hot supersaturated solution of CaCl.sub.2 or CaBr.sub.2, or a mixture thereof, is pumped under pressure down a wellbore and into a subsurface hydrate formation so as to hydrostatically fracture the formation. The CaCl.sub.2 /CaBr.sub.2 solution dissolves the solid hydrates and thereby releases the gas entrapped therein. Additionally, the solution contains a polymeric viscosifier, which operates to maintain in suspension finely divided crystalline CaCl.sub.2 /CaBr.sub.2 that precipitates from the supersaturated solution as it is cooled during injection into the formation.

  10. Production scheme for deep water hydrate deposits

    SciTech Connect

    Rose, W.; Pfannkuch, H.O.

    1982-09-01

    There is substantial evidence that enormous natural gas hydrate deposits are entrapped in the bottom sediments underlying many of the deep waters that cover the earth, as well as in subsurface permafrost sediments of the polar regions. This paper addresses the important but largely ignored question of how to recover natural gas from the deep water bottom occurrences. The first problem is to gain access to the resource, the second to promote decomposition of the hydrate, and the third is to collect and bring the exsolved gas to the surface. A scheme assumed to be technically feasible involves the use of closely-spaced flexible hoses imbedded to protrude through the underside of the hydrate layer through which warm water can be circulated downwards and recovered gas brought upwards from and to surface floating platforms equipped with pumps, compressors, conversion facilities, storage vessels and pipeline manifolds.

  11. Apparatus investigates geological aspects of gas hydrates

    USGS Publications Warehouse

    Booth, J.S.; Winters, W.J.; Dillon, William P.

    1999-01-01

    The US Geological Survey has developed a laboratory research system which allows the study of the creation and dissociation of gas hydrates under deepwater conditions and with different sediment types and pore fluids. The system called GHASTLI (gas hydrate and sediment test laboratory instrument) comprises a pressure chamber which holds a sediment specimen, and which can simulate water depths to 2,500m and different sediment overburden. Seawater and gas flow through a sediment specimen can be precisely controlled and monitored. It can simulate a wide range of geology and processes and help to improve understanding of gas hydrate processes and aid prediction of geohazards, their control and potential use as an energy source. This article describes GHASTLI and how it is able to simulate natural conditions, focusing on fluid volume, acoustic velocity-compressional and shear wave, electric resistance, temperature, pore pressure, shear strength, and permeability.

  12. Fuel cell membrane hydration and fluid metering

    DOEpatents

    Jones, Daniel O.; Walsh, Michael M.

    2003-01-01

    A hydration system includes fuel cell fluid flow plate(s) and injection port(s). Each plate has flow channel(s) with respective inlet(s) for receiving respective portion(s) of a given stream of reactant fluid for a fuel cell. Each injection port injects a portion of liquid water directly into its respective flow channel. This serves to hydrate at least corresponding part(s) of a given membrane of the corresponding fuel cell(s). The hydration system may be augmented by a metering system including flow regulator(s). Each flow regulator meters an injecting at inlet(s) of each plate of respective portions of liquid into respective portion(s) of a given stream of fluid by corresponding injection port(s).

  13. Fuel cell membrane hydration and fluid metering

    DOEpatents

    Jones, Daniel O.; Walsh, Michael M.

    1999-01-01

    A hydration system includes fuel cell fluid flow plate(s) and injection port(s). Each plate has flow channel(s) with respective inlet(s) for receiving respective portion(s) of a given stream of reactant fluid for a fuel cell. Each injection port injects a portion of liquid water directly into its respective flow channel in order to mix its respective portion of liquid water with the corresponding portion of the stream. This serves to hydrate at least corresponding part(s) of a given membrane of the corresponding fuel cell(s). The hydration system may be augmented by a metering system including flow regulator(s). Each flow regulator meters an injecting at inlet(s) of each plate of respective portions of liquid into respective portion(s) of a given stream of fluid by corresponding injection port(s).

  14. Gu's function scale of ion hydration force and charge size

    NASA Astrophysics Data System (ADS)

    Gu, Hong-Kan

    1997-06-01

    “Water Vapor Chemistry” as a new science was discovered and established from trace analysis in Gu's laboratory(Gu, 1991; Gu et al., 1991). Gu's Function shows that the trace metal ion concentration in water vapor has positive correlation to “specific electron affinity constant” last ionization potential I z/ion valence Z and negative correlation to ion volume V and coordination number N(Gu, 1994). Gu's Function C=f[(Iz/Z)/VN] of the bond parameter in water vapor chemistry corresponds to the potential energy function Z'e 2/r in the Schrodinger Equation of quantum chemistry. In, different ions with the same 2+ charge, the ion concentration of water—water vapor transfer may be much different. This shows that the 2+ charge of different ions has different attractive force (hydration force). This different attractive force of the charge can be scaled with the relative energy or charge size from Gu's Function.

  15. Metallization of bacterial cellulose for electrical and electronic device manufacture

    DOEpatents

    Evans, Barbara R [Oak Ridge, TN; O'Neill, Hugh M [Knoxville, TN; Jansen, Valerie Malyvanh [Memphis, TN; Woodward, Jonathan [Knoxville, TN

    2010-09-28

    A method for the deposition of metals in bacterial cellulose and for the employment of the metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The method for impregnating bacterial cellulose with a metal comprises placing a bacterial cellulose matrix in a solution of a metal salt such that the metal salt is reduced to metallic form and the metal precipitates in or on the matrix. The method for the construction of a fuel cell comprises placing a hydrated bacterial cellulose support structure in a solution of a metal salt such that the metal precipitates in or on the support structure, inserting contact wires into two pieces of the metal impregnated support structure, placing the two pieces of metal impregnated support structure on opposite sides of a layer of hydrated bacterial cellulose, and dehydrating the three layer structure to create a fuel cell.

  16. Metallization of bacterial cellulose for electrical and electronic device manufacture

    DOEpatents

    Evans, Barbara R.; O'Neill, Hugh M.; Jansen, Valerie Malyvanh; Woodward, Jonathan

    2011-06-07

    A method for the deposition of metals in bacterial cellulose and for the employment of the metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The method for impregnating bacterial cellulose with a metal comprises placing a bacterial cellulose matrix in a solution of a metal salt such that the metal salt is reduced to metallic form and the metal precipitates in or on the matrix. The method for the construction of a fuel cell comprises placing a hydrated bacterial cellulose support structure in a solution of a metal salt such that the metal precipitates in or on the support structure, inserting contact wires into two pieces of the metal impregnated support structure, placing the two pieces of metal impregnated support structure on opposite sides of a layer of hydrated bacterial cellulose, and dehydrating the three layer structure to create a fuel cell.

  17. Mapping the Hydration Dynamics of Ubiquitin

    PubMed Central

    Nucci, Nathaniel V.; Pometun, Maxim S.; Wand, A. Joshua

    2011-01-01

    The nature of water’s interaction with biomolecules such as proteins has been difficult to examine in detail at atomic resolution. Solution NMR spectroscopy is potentially a powerful method for characterizing both the structural and temporal aspects of protein hydration but has been plagued by artifacts. Encapsulation of the protein of interest within the aqueous core of a reverse micelle particle results in a general slowing of water dynamics, significant reduction in hydrogen exchange chemistry and elimination of contributions from bulk water thereby enabling the use of nuclear Overhauser effects to quantify interactions between the protein surface and hydration water. Here we extend this approach to allow use of dipolar interactions between hydration water and hydrogens bonded to protein carbon atoms. By manipulating the molecular reorientation time of the reverse micelle particle through use of low viscosity liquid propane, the T1ρ relaxation time constants of 1H bonded to 13C were sufficiently lengthened to allow high quality rotating frame nuclear Overhauser effects to be obtained. These data supplement previous results obtained from dipolar interactions between the protein and hydrogens bonded to nitrogen and in aggregate cover the majority of the molecular surface of the protein. A wide range of hydration dynamics is observed. Clustering of hydration dynamics on the molecular surface is also seen. Regions of long-lived hydration water correspond with regions of the protein that participate in molecular recognition of binding partners implying that the contribution of the solvent entropy to the entropy of binding has been maximized through evolution. PMID:21761828

  18. Promoter effect of hydration on the nucleation of nanoparticles: direct observation for gold and copper on rutile TiO2 (110).

    PubMed

    Iachella, Mathilde; Wilson, Axel; Naitabdi, Ahmed; Bernard, Romain; Prévot, Geoffroy; Loffreda, David

    2016-09-28

    Direct observation of the promoting effect of hydration on the nucleation of gold and copper nanoparticles supported on partially reduced rutile TiO2 (110) is achieved by combined scanning tunneling microscopy experiments and density functional theory calculations. The experiments show a clear difference between the two metals. Gold nanoparticles grow at the vicinity of the surface hydroxyl domains, whereas the nucleation of copper is not substantially affected by hydration. The nucleation of gold on surface oxygen vacancies is observed although this is not the only preferential site. Theoretical calculations of the coadsorbed phases of gold, copper and hydroxyl species on stoichiometric and reduced TiO2 (110) surfaces under relevant conditions of temperature and pressure support the experimental interpretation. Surface hydration tends to stabilize significantly gold adsorption on the stoichiometric support, while its influence on copper adsorption is not pronounced. The theoretical analysis shows that the early stages of the nucleation on hydrated stoichiometric surfaces correspond to mono-hydroxylated metallic species co-chemisorbed with hydroxyl species, whereas those on hydrated reduced surfaces are metallic atoms bound to oxygen vacancies and weakly perturbed by surface hydration. PMID:27603921

  19. Arctic Gas hydrate, Environment and Climate

    NASA Astrophysics Data System (ADS)

    Mienert, Jurgen; Andreassen, Karin; Bünz, Stefan; Carroll, JoLynn; Ferre, Benedicte; Knies, Jochen; Panieri, Giuliana; Rasmussen, Tine; Myhre, Cathrine Lund

    2015-04-01

    Arctic methane hydrate exists on land beneath permafrost regions and offshore in shelf and continental margins sediments. Methane or gas hydrate, an ice-like substrate, consists mainly of light hydrocarbons (mostly methane from biogenic sources but also ethane and propane from thermogenic sources) entrapped by a rigid cage of water molecules. The pressure created by the overlying water and sediments offshore stabilizes the CH4 in continental margins at a temperature range well above freezing point; consequently CH4 exists as methane ice beneath the seabed. Though the accurate volume of Arctic methane hydrate and thus the methane stored in hydrates throughout the Quaternary is still unknown it must be enormous if one considers the vast regions of Arctic continental shelves and margins as well as permafrost areas offshore and on land. Today's subseabed methane hydrate reservoirs are the remnants from the last ice age and remain elusive targets for both unconventional energy and as a natural methane emitter influencing ocean environments and ecosystems. It is still contentious at what rate Arctic warming may govern hydrate melting, and whether the methane ascending from the ocean floor through the hydrosphere reaches the atmosphere. As indicated by Greenland ice core records, the atmospheric methane concentration rose rapidly from ca. 500 ppb to ca. 750 ppb over a short time period of just 150 years at the termination of the younger Dryas period ca. 11600 years ago, but the dissociation of large quantities of methane hydrates on the ocean floor have not been documented yet (Brook et al., 2014 and references within). But with the major projected warming and sea ice melting trend (Knies et al., 2014) one may ask, for how long will CH4 stay trapped in methane hydrates if surface and deep-ocean water masses will warm and permafrost continuous to melt (Portnov et al. 2014). How much of the Arctic methane will be consumed by the micro- and macrofauna, how much will

  20. Component analysis of the protein hydration entropy

    NASA Astrophysics Data System (ADS)

    Chong, Song-Ho; Ham, Sihyun

    2012-05-01

    We report the development of an atomic decomposition method of the protein solvation entropy in water, which allows us to understand global change in the solvation entropy in terms of local changes in protein conformation as well as in hydration structure. This method can be implemented via a combined approach based on molecular dynamics simulation and integral-equation theory of liquids. An illustrative application is made to 42-residue amyloid-beta protein in water. We demonstrate how this method enables one to elucidate the molecular origin for the hydration entropy change upon conformational transitions of protein.

  1. Morphology of methane hydrate host sediments

    USGS Publications Warehouse

    Jones, K.W.; Feng, H.; Tomov, S.; Winters, W.J.; Eaton, M.; Mahajan, D.

    2005-01-01

    The morphological features including porosity and grains of methane hydrate host sediments were investigated using synchrotron computed microtomography (CMT) technique. The sediment sample was obtained during Ocean Drilling Program Leg 164 on the Blake Ridge at water depth of 2278.5 m. The CMT experiment was performed at the Brookhaven National Synchrotron Light Source facility. The analysis gave ample porosity, specific surface area, mean particle size, and tortuosity. The method was found to be highly effective for the study of methane hydrate host sediments.

  2. Experimental Study of Gas Hydrate Dynamics

    NASA Astrophysics Data System (ADS)

    Fandino, O.; Ruffine, L.

    2011-12-01

    Important quantities of methane and other gases are trapped below the seafloor and in the permafrost by an ice-like solid, called gas hydrates or clathrate hydrates. The latter is formed when water is mixing with different gases at high pressures and low temperatures. Due to a their possible use as a source of energy [1] or the problematic related to flow assurance failure in pipelines [2] the understanding of their processes of formation/destabilisation of these structures becomes a goal for many laboratories research as well as industries. In this work we present an experimental study on the stochastic behaviour of hydrate formation from a bulk phase. The method used here for the experiments was to repeat several time the same hydrate formation procedure and to notice the different from one experiment to another. A variable-volume type high-pressure apparatus with two sapphire windows was used. This device, already presented by Ruffine et al.[3], allows us to perform both kinetics and phase equilibrium measurements. Three initial pressure conditions were considered here, 5.0 MPa, 7.5 MPa and 10.0 MPa. Hydrates have been formed, then allowed to dissociate by stepwise heating. The memory effect has also been investigated after complete dissociation. It turned out that, although the thermodynamics conditions of formation and/or destabilization were reproducible. An attempt to determine the influence of pressure on the nucleation induction time will be discussed. References 1. Sum, A. K.; Koh, C. A.; Sloan, E. D., Clathrate Hydrates: From Laboratory Science to Engineering Practice. Industrial & Engineering Chemistry Research 2009, 48, 7457-7465. 2. Sloan, E. D., A changing hydrate paradigm-from apprehension to avoidance to risk management. Fluid Phase Equilibria 2005, 228, 67-74. 3. Ruffine, L.; Donval, J. P.; Charlou, J. L.; Cremière, A.; Zehnder, B. H., Experimental study of gas hydrate formation and destabilisation using a novel high-pressure apparatus. Marine

  3. Simulation of subsea gas hydrate exploitation

    NASA Astrophysics Data System (ADS)

    Janicki, Georg; Schlüter, Stefan; Hennig, Torsten; Deerberg, Görge

    2014-05-01

    The recovery of methane from gas hydrate layers that have been detected in several subsea sediments and permafrost regions around the world is a promising perspective to overcome future shortages in natural gas supply. Being aware that conventional natural gas resources are limited, research is going on to develop technologies for the production of natural gas from such new sources. Thus various research programs have started since the early 1990s in Japan, USA, Canada, India, and Germany to investigate hydrate deposits and develop required technologies. In recent years, intensive research has focussed on the capture and storage of CO2 from combustion processes to reduce climate impact. While different natural or man-made reservoirs like deep aquifers, exhausted oil and gas deposits or other geological formations are considered to store gaseous or liquid CO2, the storage of CO2 as hydrate in former methane hydrate fields is another promising alternative. Due to beneficial stability conditions, methane recovery may be well combined with CO2 storage in the form of hydrates. Regarding technological implementation many problems have to be overcome. Especially mixing, heat and mass transfer in the reservoir are limiting factors causing very long process times. Within the scope of the German research project »SUGAR« different technological approaches for the optimized exploitation of gas hydrate deposits are evaluated and compared by means of dynamic system simulations and analysis. Detailed mathematical models for the most relevant chemical and physical processes are developed. The basic mechanisms of gas hydrate formation/dissociation and heat and mass transport in porous media are considered and implemented into simulation programs. Simulations based on geological field data have been carried out. The studies focus on the potential of gas production from turbidites and their fitness for CO2 storage. The effects occurring during gas production and CO2 storage within

  4. Mechanical instability of monocrystalline and polycrystalline methane hydrates

    PubMed Central

    Wu, Jianyang; Ning, Fulong; Trinh, Thuat T.; Kjelstrup, Signe; Vlugt, Thijs J. H.; He, Jianying; Skallerud, Bjørn H.; Zhang, Zhiliang

    2015-01-01

    Despite observations of massive methane release and geohazards associated with gas hydrate instability in nature, as well as ductile flow accompanying hydrate dissociation in artificial polycrystalline methane hydrates in the laboratory, the destabilising mechanisms of gas hydrates under deformation and their grain-boundary structures have not yet been elucidated at the molecular level. Here we report direct molecular dynamics simulations of the material instability of monocrystalline and polycrystalline methane hydrates under mechanical loading. The results show dislocation-free brittle failure in monocrystalline hydrates and an unexpected crossover from strengthening to weakening in polycrystals. Upon uniaxial depressurisation, strain-induced hydrate dissociation accompanied by grain-boundary decohesion and sliding destabilises the polycrystals. In contrast, upon compression, appreciable solid-state structural transformation dominates the response. These findings provide molecular insight not only into the metastable structures of grain boundaries, but also into unusual ductile flow with hydrate dissociation as observed during macroscopic compression experiments. PMID:26522051

  5. Mechanical instability of monocrystalline and polycrystalline methane hydrates.

    PubMed

    Wu, Jianyang; Ning, Fulong; Trinh, Thuat T; Kjelstrup, Signe; Vlugt, Thijs J H; He, Jianying; Skallerud, Bjørn H; Zhang, Zhiliang

    2015-01-01

    Despite observations of massive methane release and geohazards associated with gas hydrate instability in nature, as well as ductile flow accompanying hydrate dissociation in artificial polycrystalline methane hydrates in the laboratory, the destabilising mechanisms of gas hydrates under deformation and their grain-boundary structures have not yet been elucidated at the molecular level. Here we report direct molecular dynamics simulations of the material instability of monocrystalline and polycrystalline methane hydrates under mechanical loading. The results show dislocation-free brittle failure in monocrystalline hydrates and an unexpected crossover from strengthening to weakening in polycrystals. Upon uniaxial depressurisation, strain-induced hydrate dissociation accompanied by grain-boundary decohesion and sliding destabilises the polycrystals. In contrast, upon compression, appreciable solid-state structural transformation dominates the response. These findings provide molecular insight not only into the metastable structures of grain boundaries, but also into unusual ductile flow with hydrate dissociation as observed during macroscopic compression experiments. PMID:26522051

  6. Gas hydrate of Lake Baikal: Discovery and varieties

    NASA Astrophysics Data System (ADS)

    Khlystov, Oleg; De Batist, Marc; Shoji, Hitoshi; Hachikubo, Akihiro; Nishio, Shinya; Naudts, Lieven; Poort, Jeffrey; Khabuev, Andrey; Belousov, Oleg; Manakov, Andrey; Kalmychkov, Gennаdy

    2013-01-01

    This paper summarizes the results of recent gas-hydrate studies in Lake Baikal, the only fresh-water lake in the world containing gas hydrates in its sedimentary infill. We provide a historical overview of the different investigations and discoveries and highlight some recent breakthroughs in our understanding of the Baikal hydrate system. So far, 21 sites of gas hydrate occurrence have been discovered. Gas hydrates are of structures I and II, which are of thermogenic, microbial, and mixed origin. At the 15 sites, gas hydrates were found in mud volcanoes, and the rest six - near gas discharges. Additionally, depending on type of discharge and gas hydrate structure, they were visually different. Investigations using MIR submersibles allowed finding of gas hydrates at the bottom surface of Lake Baikal at the three sites.

  7. Timescales for migration of atmospherically derived sulphate through an alpine/subalpine watershed, Loch Vale, Colorado

    USGS Publications Warehouse

    Michel, R.L.; Campbell, D.; Clow, D.; Turk, J.T.

    2000-01-01

    Sulphur 35, a cosmogenically produced radioisotope with a short half-life (87 days), was measured in snowpack during 1993-1997 and at four locations within the Loch Vale watershed during 1995-1997. The four sites include the two main drainages in the watershed, Andrews Creek and Icy Brook, a small south facing catchment flowing into Andrews Creek (Andrews Spring 1), and a similar north facing catchment flowing out of a scree field into Icy Brook (Spring 19). Concentrations ranged from a high of almost 50 mBq/L for a sample from Spring 19 in June 1996 to a concentration near the detection limit for a sample from Andrews Creek in April 1997. Sulphur 35 concentrations were normalized to sulphate (as mBq/mg SO4/-2) and were decay-corrected to a Julian day of 90 (April 1) for each year. Snowpack had the highest 35S concentration with an average concentration of 53 mBq/mg SO4-2. Concentrations in the streams were much lower, even when corrected for decay relative to JD 90. The large 35S concentrations found in Spring 19 were the result of increases in concentration due to sublimation and/or evapotranspiration and were lower than snowpack when normalized to sulphate. Using 35S concentrations found in snowpack as of JD 90 as a beginning concentration, the fraction of sulphate in streamflow that was derived from atmospheric deposition within the prior water year was estimated. For Icy Brook and Andrews Creek the fraction of the sulphate in streamflow derived from that year's snowpack and precipitation was low prior to the beginning of the main spring melt, reached a maximum during the period of maximum flow, and decreased as the summer progressed. A calculation of the seasonal flux indicated that about 40% of the sulphate that flowed out of the watershed was derived from atmospheric sulphate deposited during the previous year. This suggests that more than half of the sulphate deposited in the watershed by atmospheric processes during the previous year was removed during the

  8. A new sulphate metabolite as a long-term marker of metandienone misuse.

    PubMed

    Gómez, C; Pozo, O J; Garrostas, L; Segura, J; Ventura, R

    2013-12-11

    Metandienone is one of the most frequently detected anabolic androgenic steroids in sports drug testing. Metandienone misuse is commonly detected by monitoring different metabolites excreted free or conjugated with glucuronic acid using gas chromatography mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) after hydrolysis with β-glucuronidase and liquid-liquid extraction. It is known that several metabolites are the result of the formation of sulphate conjugates in C17, which are converted to their 17-epimers in urine. Therefore, sulphation is an important phase II metabolic pathway of metandienone that has not been comprehensively studied. The aim of this work was to evaluate the sulphate fraction of metandienone metabolism by LC-MS/MS. Seven sulphate metabolites were detected after the analysis of excretion study samples by applying different neutral loss scan, precursor ion scan and SRM methods. One of the metabolites (M1) was identified and characterised by GC-MS/MS and LC-MS/MS as 18-nor-17β-hydroxymethyl-17α-methylandrost-1,4,13-triene-3-one sulphate. M1 could be detected up to 26 days after the administration of a single dose of metandienone (5 mg), thus improving the period in which the misuse can be reported with respect to the last long-term metandienone metabolite described (18-nor-17β-hydroxymethyl-17α-methylandrost-1,4,13-triene-3-one excreted in the glucuronide fraction). PMID:24055830

  9. Methane production and simultaneous sulphate reduction in anoxic, salt marsh sediments

    USGS Publications Warehouse

    Oremland, R.S.; Marsh, L.M.; Polcin, S.

    1982-01-01

    It has been generally believed that sulphate reduction precludes methane generation during diagenesis of anoxic sediments1,2. Because most biogenic methane formed in nature is thought to derive either from acetate cleavage or by hydrogen reduction of carbon dioxide3-6, the removal of these compounds by the energetically more efficient sulphate-reducing bacteria can impose a substrate limitation on methanogenic bacteria 7-9. However, two known species of methanogens, Methanosarcina barkeri and Methanococcus mazei, can grow on and produce methane from methanol and methylated amines10-13. In addition, these compounds stimulate methane production by bacterial enrichments from the rumen11,14 and aquatic muds13,14. Methanol can enter anaerobic food webs through bacterial degradation of lignins15 or pectin16, and methylated amines can be produced either from decomposition of substances like choline, creatine and betaine13,14 or by bacterial reduction of trimethylamine oxide17, a common metabolite and excretory product of marine animals. However, the relative importance of methanol and methylated amines as precursors of methane in sediments has not been previously examined. We now report that methanol and trimethylamine are important substrates for methanogenic bacteria in salt marsh sediments and that these compounds may account for the bulk of methane produced therein. Furthermore, because these compounds do not stimulate sulphate reduction, methanogenesis and sulphate reduction can operate concurrently in sulphate-containing anoxic sediments. ?? 1982 Nature Publishing Group.

  10. Resistance of class C fly ash belite cement to simulated sodium sulphate radioactive liquid waste attack.

    PubMed

    Guerrero, A; Goñi, S; Allegro, V R

    2009-01-30

    The resistance of class C fly ash belite cement (FABC-2-W) to concentrated sodium sulphate salts associated with low level wastes (LLW) and medium level wastes (MLW) is discussed. This study was carried out according to the Koch and Steinegger methodology by testing the flexural strength of mortars immersed in simulated radioactive liquid waste rich in sulphate (48,000 ppm) and demineralised water (used as a reference), at 20 degrees C and 40 degrees C over a period of 180 days. The reaction mechanisms of sulphate ion with the mortar was carried out through a microstructure study, which included the use of Scanning electron microscopy (SEM), porosity and pore-size distribution and X-ray diffraction (XRD). The results showed that the FABC mortar was stable against simulated sulphate radioactive liquid waste (SSRLW) attack at the two chosen temperatures. The enhancement of mechanical properties was a result of the formation of non-expansive ettringite inside the pores and an alkaline activation of the hydraulic activity of cement promoted by the ingress of sulphate. Accordingly, the microstructure was strongly refined.

  11. Structural and immunological characterization of sulphatides: relevance of sulphate moieties in Trypanosoma cruzi glycoconjugates.

    PubMed

    Acosta, D M; Soprano, L L; Ferrero, M R; Esteva, M I; Riarte, A; Couto, A S; Duschak, V G

    2012-11-01

    Sulphoglycosphingolipids, present on the surface of diverse cells, participate in the regulation of various cellular events. However, little is known about the structure and the role of sulphoglycosphingolipids in trypanosomatids. Herein, sulphated dihexosylceramide structures - composed mainly of sphingosine as the long chain base acylated with stearic acid - have been determined for the first time in Trypanosoma cruzi epimastigotes by UV-MALDI-TOF-MS analysis. Interestingly, inhibition ELISA assays using cruzipain as antigen and polyclonal rabbit antibodies specific for cruzipain, the major cysteine proteinase of T. cruzi, or for its C-terminal domain, have demonstrated (i) that sulphate epitopes are shared between cruzipain and sulphatides of T. cruzi, (ii) that cross-reactivity maps to the C-terminal domain and (iii) the existence of other antigenic determinants in the glycolipidic structures. These features provide evidence that sulphate groups are antigenic in sulphate-containing parasite glycoconjugates. Furthermore, IgG2 antibody levels inversely correlate with disease severity in chronic Chagas disease patients, suggesting that IgG2 antibodies specific for sulphated epitopes might be associated with protective immunity and might be considered as potential surrogates of the course of chronic Chagas disease. PMID:22738032

  12. The effects of zinc sulphate on hypercholesterolaemia induced by cholesterol-choleate in rats.

    PubMed

    Cho, C H; Chen, S M; Ogle, C W

    1985-05-01

    The effects of zinc sulphate on cholesterol-choleate-induced hypercholesterolaemia were studied in rats. Zinc sulphate (20 or 40 mg/kg, p.o. once daily for 5 days) administration, which raised serum zinc levels, significantly increased bile acid secretion and lowered high-density lipoprotein-cholesterol (HDL-C) levels in the serum. Cholesterol-choleate, given by the same route and schedule, markedly elevated serum total cholesterol level, but decreased serum HDL-C concentration. Bile acid in serum and in bile was also increased, but these changes were inhibited by zinc sulphate pretreatment. Zinc sulphate also worsened the decrease in HDL-C and slightly prolonged the elevation in total cholesterol produced by cholesterol-choleate administration. It is concluded that the moderate increase in serum total cholesterol level by zinc sulphate could be due to inhibition of hepatic metabolism of cholesterol to bile acid. The specific action of zinc ions on HDL-C metabolism is discussed.

  13. Effect of folic acid and zinc sulphate on endocrine parameters and seminal antioxidant level after varicocelectomy.

    PubMed

    Nematollahi-Mahani, S N; Azizollahi, G H; Baneshi, M R; Safari, Z; Azizollahi, S

    2014-04-01

    Varicocele is among the most common problems which may lead to male infertility. Spermatogenesis is impaired as a consequence of this vascular defect, through mechanisms that are not well described. This study aimed to evaluate serum hormonal level (inhibin B, FSH and testosterone) and seminal plasma antioxidant defence levels after folic acid and zinc sulphate administration in varicocelectomised patients. Participants were randomly allocated to four experimental groups. Our randomisation schedule was as follows: zinc sulphate/folic acid, folic acid, zinc sulphate and placebo. The patients underwent varicocelectomy, before which a blood and semen sample were obtained and also three and six months after varicocelectomy for evaluation of blood hormonal level (FSH, testosterone, inhibin B) and seminal oxidative stress status (nitric oxide, superoxide dismutase, total antioxidant capacity). Patients in different groups took orally one capsule per day after dinner following varicocelectomy for 6 months. A significant rise in peripheral blood inhibin B and seminal plasma activity was detected in the zinc sulphate/folic acid group after 6 months. The present clinical trial indicates a change in the hormonal status of varicocelectomised patients following long-term administration of zinc sulphate and folic acid.

  14. Improvement of the hemocompatibility of PET surfaces using different sulphated polysaccharides as coating materials.

    PubMed

    Fasl, H; Stana, J; Stropnik, D; Strnad, S; Stana-Kleinschek, K; Ribitsch, V

    2010-02-01

    In this study, sulphated polysaccharides were investigated in respect to their blood compatibility properties (hemocompatibility). Pure chitosan was treated with sulphating agents such as SO(3)/pyridine complex and chlorosulfonic acid (HClSO(3)) to obtain 3,6-O-sulfochitosan with low and high concentration of sulfur. These synthetically derived materials and the commercially available sulphated polysaccharides heparin and dextran sulfate, both with high concentrations of sulfur, were coated onto PET foils to act as surfaces with strong antithrombotic activity. This treatment should lead to better blood compatibility properties of PET materials for medical applications. To examine this, the optimized free hemoglobin method was applied to determine the antithrombotic activity of these surfaces. Glass as the standard thrombotic surface and a heparin-coated PET surface as a surface well-known for its strong antithrombotic activity were used as internal references. The experiments showed that dextran sulfate and sulphated chitosan with high concentrations of sulfur demonstrated the same antithrombotic activity as heparin over the whole period of measurement time. In addition, a relationship between the sulfur concentration in these sulphated polysaccharides and their blood compatibility properties can be demonstrated in this article.

  15. Risk minimisation of FGD gypsum leachates by incorporation of aluminium sulphate.

    PubMed

    Alvarez-Ayuso, E; Querol, X; Ballesteros, J C; Giménez, A

    2008-11-15

    The incorporation of aluminium sulphate to (flue gas desulphurisation) FGD gypsum before its disposal was investigated as a way to minimise the risk supposed by the high fluoride content of its leachates. Using a bath method the kinetic and equilibrium processes of fluoride removal by aluminium sulphate were studied at fluoride/aluminium molar concentration (F/Al) ratios in the range 1.75 10(-2)-1.75 under the pH conditions (about 6.5) of FGD gypsum leachates. It was found that fluoride removal was a very fast process at any of the (F/Al) ratios subject of study, with equilibrium attained within the first 15 min of interaction. High decreases in solution fluoride concentrations (50-80%) were found at the equilibrium state. The use of aluminium sulphate in the stabilization of FGD gypsum proved to greatly decrease its fluoride leachable content (in the range 20-90% for aluminium sulphate doses of 0.1-5%, as determined by the European standard EN 12457-4). Such fluoride leaching minimisation assures the characterization of this by-product as a waste acceptable at landfills for non-hazardous wastes according to the Council Decision 2003/33/EC on waste disposal. Furthermore, as derived from column leaching studies, the proposed stabilization system showed to be highly effective in simulated conditions of disposal, displaying fluoride leaching reduction values about 55 and 80% for aluminium sulphate added amounts of 1 and 2%, respectively.

  16. Effect of aluminium and sulphate on anaerobic digestion of sludge from wastewater enhanced primary treatment.

    PubMed

    Cabirol, N; Barragán, E J; Durán, A; Noyola, A

    2003-01-01

    The combined and individual effects of aluminium and sulphate at concentrations of 1,000 mg/l as Al(OH)3, and 150 mgSO4(2-)/L as K2SO4, respectively, on the anaerobic digestion of sludge from enhanced primary treatment (EPT) were evaluated in 1 L capacity semi continuous reactors. It was found that at 59 days, aluminium inhibits the specific methanogenic activity (SMA) of methanogenic and acetogenic bacteria resulting in a 50% to 72% decrease. Sulphate also inhibits (48% to 65%) the SMA of the same type of bacteria. Methanogenic and acetogenic bacteria were able to adapt, to a different extent, to the assayed concentrations of aluminium and sulphate. However, the combination of aluminium and sulphate resulted in a higher inhibition, especially of the hydrogenophilic methanogenic bacteria. Indeed, this effect remained during the time of the experiment, maintaining an inhibition of 44% at 114 days. Feeding with EPT sludge led to a bigger decrease in SMA of each bacterial group, with respect to the other treatments with time. It is concluded that the acidification of anaerobic reactors fed with EPT sludge is due, among other causes, to the concurrent presence of aluminium and sulphate.

  17. Composition and structure of an iron-bearing, layered double hydroxide (LDH) - Green rust sodium sulphate

    NASA Astrophysics Data System (ADS)

    Christiansen, B. C.; Balic-Zunic, T.; Petit, P.-O.; Frandsen, C.; Mørup, S.; Geckeis, H.; Katerinopoulou, A.; Stipp, S. L. Svane

    2009-06-01

    Mixed-valent Fe(II),Fe(III)-layered hydroxide, known as green rust, was synthesized from slightly basic, sodium sulphate solutions in an oxygen-free glove box. Solution conditions were monitored with pH and Eh electrodes and optimized to ensure a pure sulphate green-rust phase. The solid was characterised using Mössbauer spectroscopy, X-ray diffraction, scanning electron microscopy and atomic force microscopy. The composition of the solution from which the green rust precipitated was established by mass and absorption spectroscopy. The sulphate form of green rust is composed of brucite-like layers with Fe(II) and Fe(III) in an ordered distribution. The interlayers contain sulphate, water and sodium in an arrangement characteristic for the nikischerite group. The crystal structure is highly disordered by stacking faults. The composition, formula and crystallographic parameters are: NaFe(II) 6Fe(III) 3(SO 4) 2(OH) 18·12H 2O, space group P-3, a = 9.528(6) Å, c = 10.968(8) Å and Z = 1. Green rust sodium sulphate, GR, crystallizes in thin, hexagonal plates. Particles range from less than 50 nm to 2 μm in diameter and are 40 nm thick or less. The material is redox active and reaction rates are fast. Extremely small particle size and high surface area contribute to rapid oxidation, transforming green rust to an Fe(III)-phase within minutes.

  18. Sulphate reducing activity detected in soil samples from Antarctica, Ecology Glacier Forefield, King George Island.

    PubMed

    Wolicka, Dorota; Zdanowski, Marek K; Żmuda-Baranowska, Magdalena J; Poszytek, Anna; Grzesiak, Jakub

    2014-01-01

    We determined sulphate-reducing activities in media inoculated with soils and with kettle lake sediments in order to investigate their potential in geomicrobiological processes in low-temperature, terrestrial maritime Antarctic habitats. Soil and sediment samples were collected in a glacier valley abandoned by Ecology Glacier during the last 30 years: from a new formed kettle lake sediment and forefield soil derived from ground moraine. Inoculated with these samples, liquid Postgate C and minimal media supplemented with various carbon sources as electron donors were incubated for 8 weeks at 4°C. High rates of sulphate reduction were observed only in media inoculated with soil. No sulphate reduction was detected in media inoculated with kettle lake sediments. In soil samples culture media calcite and elemental sulphur deposits were observed, demonstrating that sulphate-reducing activity is associated with a potential to mineral formation in cold environments. Cells observed on scanning microscopy (SEM) micrographs of post-culture-soil deposits could be responsible for sulphate-reducing activity. PMID:25804064

  19. Resistance of class C fly ash belite cement to simulated sodium sulphate radioactive liquid waste attack.

    PubMed

    Guerrero, A; Goñi, S; Allegro, V R

    2009-01-30

    The resistance of class C fly ash belite cement (FABC-2-W) to concentrated sodium sulphate salts associated with low level wastes (LLW) and medium level wastes (MLW) is discussed. This study was carried out according to the Koch and Steinegger methodology by testing the flexural strength of mortars immersed in simulated radioactive liquid waste rich in sulphate (48,000 ppm) and demineralised water (used as a reference), at 20 degrees C and 40 degrees C over a period of 180 days. The reaction mechanisms of sulphate ion with the mortar was carried out through a microstructure study, which included the use of Scanning electron microscopy (SEM), porosity and pore-size distribution and X-ray diffraction (XRD). The results showed that the FABC mortar was stable against simulated sulphate radioactive liquid waste (SSRLW) attack at the two chosen temperatures. The enhancement of mechanical properties was a result of the formation of non-expansive ettringite inside the pores and an alkaline activation of the hydraulic activity of cement promoted by the ingress of sulphate. Accordingly, the microstructure was strongly refined. PMID:18524482

  20. Sulphate reducing activity detected in soil samples from Antarctica, Ecology Glacier Forefield, King George Island.

    PubMed

    Wolicka, Dorota; Zdanowski, Marek K; Żmuda-Baranowska, Magdalena J; Poszytek, Anna; Grzesiak, Jakub

    2014-01-01

    We determined sulphate-reducing activities in media inoculated with soils and with kettle lake sediments in order to investigate their potential in geomicrobiological processes in low-temperature, terrestrial maritime Antarctic habitats. Soil and sediment samples were collected in a glacier valley abandoned by Ecology Glacier during the last 30 years: from a new formed kettle lake sediment and forefield soil derived from ground moraine. Inoculated with these samples, liquid Postgate C and minimal media supplemented with various carbon sources as electron donors were incubated for 8 weeks at 4°C. High rates of sulphate reduction were observed only in media inoculated with soil. No sulphate reduction was detected in media inoculated with kettle lake sediments. In soil samples culture media calcite and elemental sulphur deposits were observed, demonstrating that sulphate-reducing activity is associated with a potential to mineral formation in cold environments. Cells observed on scanning microscopy (SEM) micrographs of post-culture-soil deposits could be responsible for sulphate-reducing activity.