Sample records for low-enthalpy mineral waters

  1. Study of Shallow Low-Enthalpy Geothermal Resources Using Integrated Geophysical Methods

    NASA Astrophysics Data System (ADS)

    De Giorgi, Lara; Leucci, Giovanni

    2015-02-01

    The paper is focused on low enthalpy geothermal exploration performed in south Italy and provides an integrated presentation of geological, hydrogeological, and geophysical surveys carried out in the area of municipality of Lecce. Geological and hydrogeological models were performed using the stratigraphical data from 51 wells. A ground-water flow (direction and velocity) model was obtained. Using the same wells data, the ground-water annual temperature was modeled. Furthermore, the ground surface temperature records from ten meteorological stations were studied. This allowed us to obtain a model related to the variations of the temperature at different depths in the subsoil. Integrated geophysical surveys were carried out in order to explore the low-enthalpy geothermal fluids and to evaluate the results of the model. Electrical resistivity tomography (ERT) and self-potential (SP) methods were used. The results obtained upon integrating the geophysical data with the models show a low-enthalpy geothermal resource constituted by a shallow ground-water system.

  2. Geophysical techniques for low enthalpy geothermal exploration in New Zealand

    NASA Astrophysics Data System (ADS)

    Soengkono, Supri; Bromley, Chris; Reeves, Robert; Bennie, Stewart; Graham, Duncan

    2013-05-01

    Shallow warm water resources associated with low enthalpy geothermal systems are often difficult to explore using geophysical techniques, mainly because the warm water creates an insufficient physical change from the host rocks to be easily detectable. In addition, often the system also has a limited or narrow size. However, appropriate use of geophysical techniques can still help the exploration and further investigation of low enthalpy geothermal resources. We present case studies on the use of geophysical techniques for shallow warm water explorations over a variety of settings in New Zealand (mostly in the North Island) with variable degrees of success. A simple and direct method for the exploration of warm water systems is shallow temperature measurements. In some New Zealand examples, measurements of near surface temperatures helped to trace the extent of deeper thermal water. The gravity method was utilised as a structural technique for the exploration of some warm water systems in New Zealand. Our case studies show the technique can be useful in identifying basement depths and tracing fault systems associated with the occurrence of hot springs. Direct current (DC) ground resistivity measurements using a variety of electrode arrays have been the most common method for the exploration of low enthalpy geothermal resources in New Zealand. The technique can be used to detect the extent of shallow warm waters that are more electrically conductive than the surrounding cold groundwater. Ground resistivity investigations using the electromagnetic (EM) techniques of audio magnetotellurics (AMT or shallow MT), controlled source audio magnetotellurics (CSAMT) and transient electromagnetic (TEM) methods have also been used. Highly conductive clays of thermal or sedimentary origin often limit the penetration depth of the resistivity techniques and can create some interpretation difficulties. Interpretation of resistivity anomalies needs to be treated in a site specific

  3. Free enthalpies of replacing water molecules in protein binding pockets.

    PubMed

    Riniker, Sereina; Barandun, Luzi J; Diederich, François; Krämer, Oliver; Steffen, Andreas; van Gunsteren, Wilfred F

    2012-12-01

    Water molecules in the binding pocket of a protein and their role in ligand binding have increasingly raised interest in recent years. Displacement of such water molecules by ligand atoms can be either favourable or unfavourable for ligand binding depending on the change in free enthalpy. In this study, we investigate the displacement of water molecules by an apolar probe in the binding pocket of two proteins, cyclin-dependent kinase 2 and tRNA-guanine transglycosylase, using the method of enveloping distribution sampling (EDS) to obtain free enthalpy differences. In both cases, a ligand core is placed inside the respective pocket and the remaining water molecules are converted to apolar probes, both individually and in pairs. The free enthalpy difference between a water molecule and a CH(3) group at the same location in the pocket in comparison to their presence in bulk solution calculated from EDS molecular dynamics simulations corresponds to the binding free enthalpy of CH(3) at this location. From the free enthalpy difference and the enthalpy difference, the entropic contribution of the displacement can be obtained too. The overlay of the resulting occupancy volumes of the water molecules with crystal structures of analogous ligands shows qualitative correlation between experimentally measured inhibition constants and the calculated free enthalpy differences. Thus, such an EDS analysis of the water molecules in the binding pocket may give valuable insight for potency optimization in drug design.

  4. Free enthalpies of replacing water molecules in protein binding pockets

    NASA Astrophysics Data System (ADS)

    Riniker, Sereina; Barandun, Luzi J.; Diederich, François; Krämer, Oliver; Steffen, Andreas; van Gunsteren, Wilfred F.

    2012-12-01

    Water molecules in the binding pocket of a protein and their role in ligand binding have increasingly raised interest in recent years. Displacement of such water molecules by ligand atoms can be either favourable or unfavourable for ligand binding depending on the change in free enthalpy. In this study, we investigate the displacement of water molecules by an apolar probe in the binding pocket of two proteins, cyclin-dependent kinase 2 and tRNA-guanine transglycosylase, using the method of enveloping distribution sampling (EDS) to obtain free enthalpy differences. In both cases, a ligand core is placed inside the respective pocket and the remaining water molecules are converted to apolar probes, both individually and in pairs. The free enthalpy difference between a water molecule and a CH3 group at the same location in the pocket in comparison to their presence in bulk solution calculated from EDS molecular dynamics simulations corresponds to the binding free enthalpy of CH3 at this location. From the free enthalpy difference and the enthalpy difference, the entropic contribution of the displacement can be obtained too. The overlay of the resulting occupancy volumes of the water molecules with crystal structures of analogous ligands shows qualitative correlation between experimentally measured inhibition constants and the calculated free enthalpy differences. Thus, such an EDS analysis of the water molecules in the binding pocket may give valuable insight for potency optimization in drug design.

  5. Multi-Generational Drinking of Bottled Low Mineral Water Impairs Bone Quality in Female Rats

    PubMed Central

    Zeng, Hui; Wang, Lingqiao; Wang, Dahua; Luo, Jiaohua; Zhang, Liang; Huang, Yujing; Chen, Ji-an; Shu, Weiqun

    2015-01-01

    Background Because of reproductions and hormone changes, females are more sensitive to bone mineral loss during their lifetime. Bottled water has become more popular in recent years, and a large number of products are low mineral water. However, research on the effects of drinking bottled low mineral water on bone health is sparse. Objective To elucidate the skeletal effects of multi-generational bottled water drinking in female rats. Methods Rats continuously drank tap water (TW), bottled natural water (bNW), bottled mineralized water (bMW), or bottled purified water (bPW) for three generations. Results The maximum deflection, elastic deflection, and ultimate strain of the femoral diaphysis in the bNW, bMW, and bPW groups and the fracture strain in the bNW and bMW groups were significantly decreased. The tibiae calcium levels in both the bNW and bPW groups were significantly lower than that in the TW group. The tibiae and teeth magnesium levels in both the bNW and bPW groups were significantly lower than those in the TW group. The collagen turnover markers PICP (in both bNW and bPW groups) were significantly lower than that in the TW group. In all three low mineral water groups, the 1,25-dihydroxy-vitamin D levels were significantly lower than those in the TW group. Conclusion Long-term drinking of low mineral water may disturb bone metabolism and biochemical properties and therefore weaken biomechanical bone properties in females. Drinking tap water, which contains adequate minerals, was found to be better for bone health. To our knowledge, this is the first report on drinking bottled low mineral water and female bone quality on three generation model. PMID:25803851

  6. Enthalpies of solvation for dopamine hydrochloride in water-ethanol solutions

    NASA Astrophysics Data System (ADS)

    Vandyshev, V. N.; Ledenkov, S. F.; Molchanov, A. S.

    2012-10-01

    The enthalpies of dissolution of dopamine hydrochloride (H2Dop · HCl) in water-ethanol solvents containing from 0 to 0.8 mole fraction of ethanol are measured by calorimetry at 298.15 K. Standard enthalpies of transfer (Δtr H ∘) for the molecular (H2Dop) and cationic (H3Dop+) forms of dopamine from water into binary solvents are calculated from the obtained data. The enthalpies of transfer of H3Dop+ cation are determined from the enthalpies of dissolution of H2Dop · HCl using the familiar method of separating the molar quantities into ionic contributions (Ph4P+ = BPh{4/-}), and by an original alternative procedure. The effect of the composition of the binary solvent on the solvation of dopamine is considered.

  7. Inelastic neutron scattering and molecular simulation of the dynamics of interlayer water in smectite clay minerals

    DOE PAGES

    Cygan, Randall T.; Daemen, Luke L.; Ilgen, Anastasia G.; ...

    2015-11-16

    The study of mineral–water interfaces is of great importance to a variety of applications including oil and gas extraction, gas subsurface storage, environmental contaminant treatment, and nuclear waste repositories. Understanding the fundamentals of that interface is key to the success of those applications. Confinement of water in the interlayer of smectite clay minerals provides a unique environment to examine the interactions among water molecules, interlayer cations, and clay mineral surfaces. Smectite minerals are characterized by a relatively low layer charge that allows the clay to swell with increasing water content. Montmorillonite and beidellite varieties of smectite were investigated to comparemore » the impact of the location of layer charge on the interlayer structure and dynamics. Inelastic neutron scattering of hydrated and dehydrated cation-exchanged smectites was used to probe the dynamics of the interlayer water (200–900 cm –1 spectral region) and identify the shift in the librational edge as a function of the interlayer cation. Molecular dynamics simulations of equivalent phases and power spectra, derived from the resulting molecular trajectories, indicate a general shift in the librational behavior with interlayer cation that is generally consistent with the neutron scattering results for the monolayer hydrates. Both neutron scattering and power spectra exhibit librational structures affected by the location of layer charge and by the charge of the interlayer cation. Furthermore, divalent cations (Ba 2+ and Mg 2+) characterized by large hydration enthalpies typically exhibit multiple broad librational peaks compared to monovalent cations (Cs + and Na +), which have relatively small hydration enthalpies.« less

  8. [Pay attention to the human health risk of drinking low mineral water].

    PubMed

    Shu, Weiqun

    2015-10-01

    The consumption of low mineral drinking water has been increasing around the world with the shortage of water resources and the development of advanced water treatment technologies. Evidences from systematic document reviews, ecological epidemiological observations, and experimental drinking water intervention studies indicate that lack of minerals in drinking water may cause direct or indirect harm to human health, among which, the associations of magnesium in water with cardiovascular disease, as well as calcium in water with osteoporosis, are well proved by sufficient evidence. This article points out that it is urgent to pay more attention to the issues about establishment of health risk evaluation system on susceptible consuming population, establishment of lab evaluation system on water quality and health effect for non-traditional drinking water, and program of safety mineralization for demineralized or desalinated water and so on.

  9. Sodium-bicarbonated mineral water decreases aldosterone levels without affecting urinary excretion of bone minerals.

    PubMed

    Schoppen, Stefanie; Pérez-Granados, Ana M; Carbajal, Angeles; Sarriá, Beatriz; Navas-Carretero, Santiago; Pilar Vaquero, M

    2008-06-01

    AIM To assess in healthy postmenopausal women the influence of consuming sodium-bicarbonated mineral water on postprandial evolution of serum aldosterone and urinary electrolyte excretion. Eighteen postmenopausal women consumed 500 ml of two sodium-bicarbonated mineral waters (sodium-bicarbonated mineral water 1 and sodium-bicarbonated mineral water 2) and a low-mineral water with a standard meal. Postprandial blood samples were taken at 60, 120, 240, 360 and 420 min and aldosterone concentrations were measured. Postprandial urinary minerals were determined. Urinary and total mineral excretion and urinary mineral concentrations did not differ except for sodium concentration, which was significantly higher with sodium-bicarbonated mineral water 1 than with low-mineral water (P = 0.005). There was a time effect (P = 0.003) on the aldosterone concentration. At 120 min, aldosterone concentrations were lower with sodium-bicarbonated mineral water 1 (P = 0.021) and sodium-bicarbonated mineral water 2 (P = 0.030) compared with low-mineral water. Drinking a sodium-rich bicarbonated mineral water with a meal increases urinary sodium concentration excretion without changes in the excretion of potassium and bone minerals.

  10. The chemistry and isotopic composition of waters in the low-enthalpy geothermal system of Cimino-Vico Volcanic District, Italy

    USGS Publications Warehouse

    Battistel, Maria; Hurwitz, Shaul; Evans, William; Barbieri, Maurizio

    2017-01-01

    Geothermal energy exploration is based in part on interpretation of the chemistry, temperature, and discharge rate of thermal springs. Here we present the major element chemistry and the δD, δ18O, 87Sr/86Sr and δ11B isotopic ratio of groundwater from the low-enthalpy geothermal system near the city of Viterbo in the Cimino-Vico volcanic district of west-Central Italy. The geothermal system hosts many thermal springs and gas vents, but the resource is still unexploited. Water chemistry is controlled by mixing between low salinity,HCO3-rich fresh waters (<24.2°C) flowing in shallow volcanic rocks and SO4-rich thermal waters (25.3°C to 62.2°C) ascending from deep, high permeability Mesozoic limestones. The (equivalent) SO4/Cl (0.01–0.02), Na/Cl (2.82–5.83) and B/Cl ratios (0.02–0.38) of thermal waters differs from the ratios in other geothermal systems from Central Italy, probably implying a lack of hydraulic continuity across the region. The δ18O (−6.6‰ to −5.9‰) and δD (−40.60‰ to −36.30‰) isotopic composition of spring water suggest that the recharge area for the geothermal system is the summit region of Mount Cimino. The strontium isotope ratios (87Sr/86Sr) of thermal waters (0.70797–0.70805) are consistent with dissolution of the Mesozoic evaporite-carbonate units that constitute the reservoir, and the ratios of cold fresh waters mainly reflect shallow circulation through the volcanic cover and some minor admixture (<10%) of thermal water as well. The boron isotopic composition (δ11B) of fresh waters (−5.00 and 6.12‰) is similar to that of the volcanic cover, but the δ11B of thermal waters (−8.37‰ to −4.12‰) is a mismatch for the Mesozoic reservoir rocks and instead reflects dissolution of secondary boron minerals during fluid ascent through flysch units that overlie the reservoir. A slow and tortuous ascent enhances extraction of boron but also promotes conductive cooling, partially masking the heat present in the

  11. Enthalpies of formation of polyhalite: A mineral relevant to salt repository

    DOE PAGES

    Guo, Xiaofeng; Xu, Hongwu

    2017-06-02

    Polyhalite is an important coexisting mineral with halite in salt repositories for nuclear waste disposal, such as Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. The thermal stability of this mineral is a key knowledge in evaluating the integrity of a salt repository in the long term, as water may release due to thermal decomposition of polyhalite. Previous studies on structural evolution of polyhalite at elevated temperatures laid the basis for detailed calorimetric measurements. Using high-temperature oxide-melt drop-solution calorimetry at 975 K with sodium molybdate as the solvent, we have determined the standard enthalpies of formation from constituent sulfatesmore » (ΔH° f,sul), oxides (ΔH° f,ox) and elements (ΔH° f,ele) of a polyhalite sample with the composition of K 2Ca 2Mg(SO 4) 4·1.95H 2O from the Salado formation at the WIPP site. The obtained results are: ΔH° f,sul = -152.5 ± 5.3 kJ/mol, ΔH° f,ox = -1926.1 ± 10.5 kJ/mol, and ΔH° f,ele = -6301.2 ± 9.9 kJ/mol. Furthermore, based on the estimated formation entropies of polyhalite, its standard Gibbs free energy of formation has been derived to be in the range of -5715.3 ± 9.9 kJ/mol to -5739.3 ± 9.9 kJ/mol. In conclusion, these determined thermodynamic properties provide fundamental parameters for modeling the stability behavior of polyhalite in salt repositories.« less

  12. Characterization of Adsorption Enthalpy of Novel Water-Stable Zeolites and Metal-Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Kim, Hyunho; Cho, H. Jeremy; Narayanan, Shankar; Yang, Sungwoo; Furukawa, Hiroyasu; Schiffres, Scott; Li, Xiansen; Zhang, Yue-Biao; Jiang, Juncong; Yaghi, Omar M.; Wang, Evelyn N.

    2016-01-01

    Water adsorption is becoming increasingly important for many applications including thermal energy storage, desalination, and water harvesting. To develop such applications, it is essential to understand both adsorbent-adsorbate and adsorbate-adsorbate interactions, and also the energy required for adsorption/desorption processes of porous material-adsorbate systems, such as zeolites and metal-organic frameworks (MOFs). In this study, we present a technique to characterize the enthalpy of adsorption/desorption of zeolites and MOF-801 with water as an adsorbate by conducting desorption experiments with conventional differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). With this method, the enthalpies of adsorption of previously uncharacterized adsorbents were estimated as a function of both uptake and temperature. Our characterizations indicate that the adsorption enthalpies of type I zeolites can increase to greater than twice the latent heat whereas adsorption enthalpies of MOF-801 are nearly constant for a wide range of vapor uptakes.

  13. Characterization of Adsorption Enthalpy of Novel Water-Stable Zeolites and Metal-Organic Frameworks

    PubMed Central

    Kim, Hyunho; Cho, H. Jeremy; Narayanan, Shankar; Yang, Sungwoo; Furukawa, Hiroyasu; Schiffres, Scott; Li, Xiansen; Zhang, Yue-Biao; Jiang, Juncong; Yaghi, Omar M.; Wang, Evelyn N.

    2016-01-01

    Water adsorption is becoming increasingly important for many applications including thermal energy storage, desalination, and water harvesting. To develop such applications, it is essential to understand both adsorbent-adsorbate and adsorbate-adsorbate interactions, and also the energy required for adsorption/desorption processes of porous material-adsorbate systems, such as zeolites and metal-organic frameworks (MOFs). In this study, we present a technique to characterize the enthalpy of adsorption/desorption of zeolites and MOF-801 with water as an adsorbate by conducting desorption experiments with conventional differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). With this method, the enthalpies of adsorption of previously uncharacterized adsorbents were estimated as a function of both uptake and temperature. Our characterizations indicate that the adsorption enthalpies of type I zeolites can increase to greater than twice the latent heat whereas adsorption enthalpies of MOF-801 are nearly constant for a wide range of vapor uptakes. PMID:26796523

  14. Dominant Alcohol-Protein Interaction via Hydration-Enabled Enthalpy-Driven Binding Mechanism

    PubMed Central

    Chong, Yuan; Kleinhammes, Alfred; Tang, Pei; Xu, Yan; Wu, Yue

    2015-01-01

    Water plays an important role in weak associations of small drug molecules with proteins. Intense focus has been on binding-induced structural changes in the water network surrounding protein binding sites, especially their contributions to binding thermodynamics. However, water is also tightly coupled to protein conformations and dynamics, and so far little is known about the influence of water-protein interactions on ligand binding. Alcohols are a type of low-affinity drugs, and it remains unclear how water affects alcohol-protein interactions. Here, we present alcohol adsorption isotherms under controlled protein hydration using in-situ NMR detection. As functions of hydration level, Gibbs free energy, enthalpy, and entropy of binding were determined from the temperature dependence of isotherms. Two types of alcohol binding were found. The dominant type is low-affinity nonspecific binding, which is strongly dependent on temperature and the level of hydration. At low hydration levels, this nonspecific binding only occurs above a threshold of alcohol vapor pressure. An increased hydration level reduces this threshold, with it finally disappearing at a hydration level of h~0.2 (g water/g protein), gradually shifting alcohol binding from an entropy-driven to an enthalpy-driven process. Water at charged and polar groups on the protein surface was found to be particularly important in enabling this binding. Although further increase in hydration has smaller effects on the changes of binding enthalpy and entropy, it results in significant negative change in Gibbs free energy due to unmatched enthalpy-entropy compensation. These results show the crucial role of water-protein interplay in alcohol binding. PMID:25856773

  15. Sulphurous Mineral Waters: New Applications for Health

    PubMed Central

    Carbajo, Jose Manuel

    2017-01-01

    Sulphurous mineral waters have been traditionally used in medical hydrology as treatment for skin, respiratory, and musculoskeletal disorders. However, driven by recent intense research efforts, topical treatments are starting to show benefits for pulmonary hypertension, arterial hypertension, atherosclerosis, ischemia-reperfusion injury, heart failure, peptic ulcer, and acute and chronic inflammatory diseases. The beneficial effects of sulphurous mineral waters, sulphurous mud, or peloids made from sulphurous mineral water have been attributed to the presence of sulphur mainly in the form of hydrogen sulphide. This form is largely available in conditions of low pH when oxygen concentrations are also low. In the organism, small amounts of hydrogen sulphide are produced by some cells where they have numerous biological signalling functions. While high levels of hydrogen sulphide are extremely toxic, enzymes in the body are capable of detoxifying it by oxidation to harmless sulphate. Hence, low levels of hydrogen sulphide may be tolerated indefinitely. In this paper, we review the chemistry and actions of hydrogen sulphide in sulphurous mineral waters and its natural role in body physiology. This is followed by an update of available data on the impacts of exogenous hydrogen sulphide on the skin and internal cells and organs including new therapeutic possibilities of sulphurous mineral waters and their peloids. PMID:28484507

  16. Enthalpy characteristics of L-proline dissolution in certain water-organic mixtures at 298.15 K

    NASA Astrophysics Data System (ADS)

    Badelin, V. G.; Smirnov, V. I.

    2017-01-01

    A thermochemical study of the processes of L-proline dissolution in aqueous solutions of acetonitrile, 1,4-dioxane, acetone, dimethyl sulfoxide, nitromethane and tetrahydrofuran at T = 298.15 K in the range of organic solvent concentrations x2 = 0-0.25 mole fractions is performed. Standard values of the enthalpies of solution and transfer of L-proline from water to mixed solvent, and the enthalpy coefficients of pairwise interactions between L-proline and molecules of organic solvents, are calculated. The effect the composition of a water-organic mixture and the structure of organic solvents have on the enthalpy characteristics of L-proline dissolution and transfer is examined. The effect the energy properties of intermolecular interactions between components of a mixed solvent has on the intermolecular interactions between L-proline and molecules of cosolvent is estimated. The correlation between the enthalpy characteristics of L-proline dissolution and electron-donor properties of organic cosolvent in aqueous solutions is determined.

  17. Investigating water adsorption onto natural mineral dust particles: Linking DRIFTS experiments and BET theory

    NASA Astrophysics Data System (ADS)

    Joshi, Nitesh; Romanias, Manolis N.; Riffault, Veronique; Thevenet, Frederic

    2017-08-01

    The adsorption of water molecules on natural mineral dusts was investigated employing in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The natural dust samples originated from North and West Africa, Saudi Arabia and Gobi desert regions. Furthermore, the hygroscopicity of commercially available Arizona Test Dusts (ATDs) and Icelandic volcanic ash were examined. N2 sorption measurements, X-ray fluorescence and diffraction (XRF and XRD), as well as Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analyses were performed to determine the physicochemical properties of the particles. The water adsorption experiments were conducted in an optical cell, at room temperature under the relative humidity (RH) range of 1.9-95%. Results were simulated using a modified three-parameter Brunauer-Emmett-Teller (BET) equation. Water monolayer (ML) was formed in the RH range of 15-25%, while additional water layers were formed at higher RH. Besides, the standard adsorption enthalpies of water onto natural mineral dust samples were determined. A thorough comparison of two commercially available ATD samples indicated that size distribution and/or porosity should play a key role in particle hygroscopicity. Regarding the natural mineral particles, Ca/Si ratios, and to a lesser extent Al/Si, Na/Si, Mg/Si ratios, were found to impact the minimum RH level required for water monolayer formation. These results suggest that the hygroscopic properties of investigated African dusts are quite similar over the whole investigated RH range. Furthermore, one of the major conclusions is that under most atmospheric relative humidity conditions, natural mineral samples are always covered with at least one layer of adsorbed water.

  18. Effect of N-Methyl Substitution in the Glycine Molecule on the Enthalpy of Dissolution in Mixed Water-Alcohol Solvents at 298.15 K

    NASA Astrophysics Data System (ADS)

    Badelin, V. G.; Smirnov, V. I.

    2018-07-01

    The enthalpies of dissolution of N-methylglycine in water + ethanol, water + (1-propanol) and water + (2-propanol) are determined via calorimetry at an alcohol concentration of x 2 = 0-0.25 mole fraction. The standard values of enthalpies of dissolution (Δ_{sol}H°) and transfer (Δ_{tr}H°) of N-methylglycine from water to solution are calculated. The effect the structure and properties of N-methylglycine and the composition of a water-alcohol mixture have on N-methylglycine's enthalpy characteristics is examined. The enthalpy coefficients of pair interactions ( h xy ) between N-methylglycine and alcohol molecules are calculated. They have positive values and grow in the series ethanol (EtOH) < 1-propanol (1-PrOH), < 2-propanol (2-PrOH). A comparative analysis is performed of the enthalpy characteristics of dissolution and transfer of N-methylglycine and the analogous characteristics of glycine and DL-α-alanine in similar mixtures.

  19. Sulfide scaling in low enthalpy geothermal environments; A survey

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Criaud, A.; Fouillac, C.

    1989-01-01

    A review of the sulfide scaling phenomena in low-temperature environments is presented. While high-temperature fluids tend to deposit metal sulfides because of their high concentrations of dissolved metals and variations of temperature, pressure and fluid chemistry, low temperature media are characterized by very low metal content but much higher dissolved sulfide. In the case of the goethermal wells of the Paris Basin, detailed studies demonstrate that the relatively large concentrations of chloride and dissolved sulfide are responsible for corrosion and consequent formation of iron sulfide scale composed of mackinawite, pyrite and pyrrhotite. The effects of the exploitation schemes are farmore » less important than the corrosion of the casings. The low-enthalpy fluids that do not originate from sedimentary aquifers (such as in Iceland and Bulgaria), have a limited corrosion potential, and the thin sulfide film that appears may prevent the progress of corrosion.« less

  20. Enthalpy-entropy compensation for the solubility of drugs in solvent mixtures: paracetamol, acetanilide, and nalidixic acid in dioxane-water.

    PubMed

    Bustamante, P; Romero, S; Pena, A; Escalera, B; Reillo, A

    1998-12-01

    In earlier work, a nonlinear enthalpy-entropy compensation was observed for the solubility of phenacetin in dioxane-water mixtures. This effect had not been earlier reported for the solubility of drugs in solvent mixtures. To gain insight into the compensation effect, the behavior of the apparent thermodynamic magnitudes for the solubility of paracetamol, acetanilide, and nalidixic acid is studied in this work. The solubility of these drugs was measured at several temperatures in dioxane-water mixtures. DSC analysis was performed on the original powders and on the solid phases after equilibration with the solvent mixture. The thermal properties of the solid phases did not show significant changes. The three drugs display a solubility maximum against the cosolvent ratio. The solubility peaks of acetanilide and nalidixic acid shift to a more polar region at the higher temperatures. Nonlinear van't Hoff plots were observed for nalidixic acid whereas acetanilide and paracetamol show linear behavior at the temperature range studied. The apparent enthalpies of solution are endothermic going through a maximum at 50% dioxane. Two different mechanisms, entropy and enthalpy, are suggested to be the driving forces that increase the solubility of the three drugs. Solubility is entropy controlled at the water-rich region (0-50% dioxane) and enthalpy controlled at the dioxane-rich region (50-100% dioxane). The enthalpy-entropy compensation analysis also suggests that two different mechanisms, dependent on cosolvent ratio, are involved in the solubility enhancement of the three drugs. The plots of deltaH versus deltaG are nonlinear, and the slope changes from positive to negative above 50% dioxane. The compensation effect for the thermodynamic magnitudes of transfer from water to the aqueous mixtures can be described by a common empirical nonlinear relationship, with the exception of paracetamol, which follows a separate linear relationship at dioxane ratios above 50%. The

  1. A new method for the determination of vaporization enthalpies of ionic liquids at low temperatures.

    PubMed

    Verevkin, Sergey P; Zaitsau, Dzmitry H; Emelyanenko, Vladimir N; Heintz, Andreas

    2011-11-10

    A new method for the determination of vaporization enthalpies of extremely low volatile ILs has been developed using a newly constructed quartz crystal microbalance (QCM) vacuum setup. Because of the very high sensitivity of the QCM it has been possible to reduce the average temperature of the vaporization studies by approximately 100 K in comparison to other conventional techniques. The physical basis of the evaluation procedure has been developed and test measurements have been performed with the common ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C(2)mim][NTf(2)] extending the range of measuring vaporization enthalpies down to 363 K. The results obtained for [C(2)mim][NTf(2)] have been tested for thermodynamic consistency by comparison with data already available at higher temperatures. Comparison of the temperature-dependent vaporization enthalpy data taken from the literature show only acceptable agreement with the heat capacity difference of -40 J K(-1) mol(-1). The method developed in this work opens also a new way to obtain reliable values of vaporization enthalpies of thermally unstable ionic liquids.

  2. Geochemistry of surface-waters in mineralized and non-mineralized areas of the Yukon-Tanana Uplands

    USGS Publications Warehouse

    Wang, B.; Wanty, R.B.; Vohden, J.

    2005-01-01

    The U.S. Geological Survey (USGS) and Alaska Department of Natural Resources (ADNR) are continuing investigations on element mobility in mineralized and non-mineralized areas of the Yukon-Tanana Upland in east-central Alaska. The chemistry of stream water is evaluated in the context of regional bedrock geology and geologic structure. Sampling sites were located in the Big Delta B2 quadrangle, which includes the mineralized areas of the Pogo claim block. The area is typified by steep, subarctic-alpine, boreal forest catchment basins. Samples were collected from catchments that either cross structural features and lithologic contacts, or are underlain by a single lithology. Waters are generally dilute (< 213 mg/L TDS), and are classified as Ca2+ and Mg2+-HCO3- to Ca2+ and Mg2+-SO42- waters. Gneissic lithologies are more SO42- dominated than the intrusive units. The major-ion chemistry of the waters reflects a rock-dominated aqueous system. Trace-element concentrations in water are generally low; however, As and Sb are detected near mineralized areas but in most cases rapidly attenuated downstream and processes other than simple dilution are controlling the concentrations of these trace elements. There is a tendency toward increasing SO42- concentrations downstream in waters both proximal and distal to mineralized areas. More work is necessary to determine what proportion of the increase in SO42- could be derived from the oxidation of sulfide minerals as opposed to water influenced by the underlying gneissic units.

  3. An Intervention with Mineral Water Decreases Cardiometabolic Risk Biomarkers. A Crossover, Randomised, Controlled Trial with Two Mineral Waters in Moderately Hypercholesterolaemic Adults.

    PubMed

    Toxqui, Laura; Vaquero, M Pilar

    2016-06-28

    Water intake is essential for health maintenance and disease prevention. The effects of an intervention with two mineral waters, sodium-bicarbonated mineral water (BW) or control mineral water low in mineral content (CW), on cardiometabolic risk biomarkers were studied. In a randomised-controlled crossover-trial, sixty-four moderately hypercholesterolaemic adults were randomly assigned to consume 1 L/day of either BW (sodium, 1 g/L; bicarbonate, 2 g/L) or CW with the main meals for eight weeks, separated by an eight-week washout period. Blood lipids, lipid oxidation, glucose, insulin, aldosterone, urine pH, urinary electrolytes, blood pressure, body weight, fluid intake, energy, and nutrients from total diet and beverages were determined. Total cholesterol, LDL cholesterol, and glucose decreased (p < 0.01), oxidised LDL tended to decrease (p = 0.073), and apolipoprotein B increased during the intervention, without water type effect. Energy and carbohydrates from beverages decreased since soft drinks and fruit juice consumptions decreased throughout the trial. BW increased urinary pH (p = 0.006) and reduced calcium/creatinine excretion (p = 0.011). Urinary potassium/creatinine decreased with both waters. Consumption of 1 L/day of mineral water with the main meals reduces cardiometabolic risk biomarkers, likely to be attributed to a replacement of soft drinks by water. In addition, BW does not affect blood pressure and exerts a moderate alkalizing effect in the body.

  4. Natural mineral waters: chemical characteristics and health effects

    PubMed Central

    Quattrini, Sara; Pampaloni, Barbara; Brandi, Maria Luisa

    2016-01-01

    Summary Water contributes significantly to health and a daily intake of 1.5 to 2 liters of water should be guaranteed, because a good hydration is essential to maintain the body water equilibrium, although needs may vary among people. However, worldwide population is far from the Recommended Allowance for water intake. Among the waters for human uses, there are ‘waters (treated or not), intended for drinking, used for the food and beverages preparation or for other domestic purposes’ and natural mineral waters, that are ‘originated from an aquifer or underground reservoir, spring from one or more natural or bore sources and have specific hygienic features and, eventually, healthy properties’. According to the European Legislation (2009/54/EC Directive), physical and chemical characterization is used to make a classification of the different mineral waters, basing on the analysis of main parameters. Mineral composition enables to classify natural mineral waters as bicarbonate mineral waters, sulphate mineral waters, chloride mineral waters, calcic mineral waters, magnesiac mineral waters, fluorurate mineral waters, ferrous mineral waters and sodium-rich mineral waters. Although the concerns about bottled mineral waters (due to plasticizers and endocrine disruptors), many are the health effects of natural mineral waters and several studies explored their properties and their role in different physiological and pathological conditions. PMID:28228777

  5. Enthalpy characteristics of the dissolution of L-valine in water/formamide mixtures at 298.15 K

    NASA Astrophysics Data System (ADS)

    Smirnov, V. I.; Badelin, V. G.

    2016-11-01

    The thermochemical dissolution of L-valine in solvent mixtures H2O + (formamide, N-methylformamide, and N, N-dimethylformamide) is studied at an organic component concentration of x 2 = 0-0.35 molar fractions and a temperature of 298.15 K. The experimental data are used to calculate standard enthalpies of dissolution, the transferring of L-valine from water to a mixed solvent, and the enthalpy coefficients of pairwise interactions ( h xy ) with organic solvent molecules. The correlation between the enthalpy characteristics of the dissolution of L-valine with the composition of aqueous organic mixtures and the nature of the organic solvent (its physicochemical properties) is determined. A comparative analysis of the values of h xy of a number of aliphatic L-amino acids in similar solvent mixtures with the hydrophobicity parameters of their side chains is performed.

  6. [Mineral water as a cure].

    PubMed

    Nocco, Priska Binz

    2008-01-01

    The treatment of diseases with mineral spring water belongs to the oldest medical therapies. The "remedy" mineral water is therefore of importance also within the pharmacy. The present pharmacy historical work examines the impact of the use of mineral waters, as well as of their dried components, as therapeutic agents in the 19th and early 20th centuries, i.e. from approx. 1810 to 1930, as well as the contributions given by pharmacists in the development and analysis of mineral water springs. Beside these aspects, the aim here is also to describe the role played by pharmacists in the production of artificial mineral water as well as in the sale and wholesale of natural and artificial mineral water. In the first part of this work the situation in Switzerland and its surrounding countries, such as Germany, France, Italy and Austria, is discussed. The second part contains a case-study of the particular situation in the Canton Tessin. It is known from the scientific literature published at that time that information on mineral water was frequently reported. Starting from the beginning of the 19th century the number of such publications increased tremendously. The major part of them were publications in scientific journals or contributions to medical and pharmaceutical manuals and reference books. In particular the spa-related literature, such as spa-guides, was of growing interest to a broad public. The inclusion of monographs into the Swiss, the Cantonal as well the foreign pharmacopoeias granted a legal frame for the mineral waters and their dried components. These works are of major importance from a pharmacy historical standpoint and represent a unique proof of historical evidence of the old medicinal drug heritage. The most frequently used therapies based on mineral waters were drinking and bath cures. Several diseases, particularly those of a chronic character, were treated with mineral waters. The positive influence of these cures on the recovery of the patients

  7. Evaluation of Enthalpy Diagrams for NH3-H2O Absorption Refrigerator

    NASA Astrophysics Data System (ADS)

    Takei, Toshitaka; Saito, Kiyoshi; Kawai, Sunao

    The protection of environment is becoming a grave problem nowadays and an absorption refrigerator, which does not use fleon as a refrigerant, is acquiring a close attention. Among the absorption refrigerators, a number of ammonia-water absorption refrigerators are being used in realm such as refrigeration and ice accumulation, since this type of refrigerator can produce below zero degree products. It is essential to conduct an investigation on the characteristics of ammonia-water absorption refrigerator in detail by means of computer simulation in order to realize low cost, highly efficient operation. Unfortunately, there have been number of problems in order to conduct computer simulations. Firstly, Merkel's achievements of enthalpy diagram does not give the relational equations. And secondly, although relational equation are being proposed by Ziegler, simpler equations that can be applied to computer simulation are yet to be proposed. In this research, simper equations based on Ziegler's equations have been derived to make computer simulation concerning the performance of ammonia-water absorption refrigerator possible-Both results of computer simulations using simple equations and Merkel's enthalpy diagram respectively, have been compared with the actual experimental data of one staged ammonia-water absorption refrigerator. Consequently, it is clarified that the results from Ziegler's equations agree with experimental data better than those from Merkel's enthalpy diagram.

  8. Protonation enthalpies of metal oxides from high temperature electrophoresis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rodriguez-Santiago, V; Fedkin, Mark V.; Lvov, Serguei N.

    2012-01-01

    Surface protonation reactions play an important role in the behavior of mineral and colloidal systems, specifically in hydrothermal aqueous environments. However, studies addressing the reactions at the solid/liquid interface at temperatures above 100 C are scarce. In this study, newly and previously obtained high temperature electrophoresis data (up to 260 C) zeta potentials and isoelectric points for metal oxides, including SiO2, SnO2, ZrO2, TiO2, and Fe3O4, were used in thermodynamic analysis to derive the standard enthalpies of their surface protonation. Two different approaches were used for calculating the protonation enthalpy: one is based on thermodynamic description of the 1-pKa modelmore » for surface protonation, and another one on a combination of crystal chemistry and solvation theories which link the relative permittivity of the solid phase and the ratio of the Pauling bond strength and bond length to standard protonation enthalpy. From this analysis, two expressions relating the protonation enthalpy to the relative permittivity of the solid phase were obtained.« less

  9. Protonation enthalpies of metal oxides from high temperature electrophoresis.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rodriguez-Santiago, V; Fedkin, Mark V; Lvov, Serguei N.

    2012-01-01

    Surface protonation reactions play an important role in the behavior of mineral and colloidal systems, specifically in hydrothermal aqueous environments. However, studies addressing the reactions at the solid/liquid interface at temperatures above 100 C are scarce. In this study, newly and previously obtained high temperature electrophoresis data (up to 260 C) - zeta potentials and isoelectric points - for metal oxides, including SiO{sub 2}, SnO{sub 2}, ZrO{sub 2}, TiO{sub 2}, and Fe{sub 3}O{sub 4}, were used in thermodynamic analysis to derive the standard enthalpies of their surface protonation. Two different approaches were used for calculating the protonation enthalpy: one ismore » based on thermodynamic description of the 1-pKa model for surface protonation, and another one - on a combination of crystal chemistry and solvation theories which link the relative permittivity of the solid phase and the ratio of the Pauling bond strength and bond length to standard protonation enthalpy. From this analysis, two expressions relating the protonation enthalpy to the relative permittivity of the solid phase were obtained.« less

  10. Characterization and Thermodynamics Studies of Feldspar and Feldspathoid Minerals

    NASA Astrophysics Data System (ADS)

    Rudow, M.; Lilova, K.

    2015-12-01

    The application of thermal analysis and calorimetry for the studies of minerals has a history as long as the existence of the thermal methods themselves. New advanced calorimetric techniques have been developed for more accurate characterization of both bulk and nano materials thus impacting their design, processing, and applications. TG-DTA and TG-DSC are used to characterize the composition of complex minerals (e.g. [KxNa1-x(AlSi3)O8]) based on the weight changes and phase transformations observed with temperature increase. Additionally, those techniques allow to determine the quantity of the different types of water contained in natural feldspars and feldspathoids (absorbed, interlayer, structural). The results for several clays will be discussed. The geochemical properties and thermal stability of another class of minerals - aluminosilicate frameworks (alkali sodalities, natrolites, etc.) as related to high-level nuclear waste treatment facilities, radioactive waste storage and management were studied. The natural sodalite Na8[Al6Si6O24]Cl2 and similar frameworks with different anions are part of sodium-aluminosilicate (NAS) low activity radioactive waste produced during steam reforming process treatment. The enthalpies and entropies of formation and the hydration enthalpies of the above-mentioned feltspathoids are obtained and the effect of the different cations and anions on the thermodynamic stability was studied. The results will allow to predict the long term behavior of the compounds in the environment under different conditions.

  11. Enthalpy-entropy compensation: the role of solvation.

    PubMed

    Dragan, Anatoliy I; Read, Christopher M; Crane-Robinson, Colyn

    2017-05-01

    Structural modifications to interacting systems frequently lead to changes in both the enthalpy (heat) and entropy of the process that compensate each other, so that the Gibbs free energy is little changed: a major barrier to the development of lead compounds in drug discovery. The conventional explanation for such enthalpy-entropy compensation (EEC) is that tighter contacts lead to a more negative enthalpy but increased molecular constraints, i.e., a compensating conformational entropy reduction. Changes in solvation can also contribute to EEC but this contribution is infrequently discussed. We review long-established and recent cases of EEC and conclude that the large fluctuations in enthalpy and entropy observed are too great to be a result of only conformational changes and must result, to a considerable degree, from variations in the amounts of water immobilized or released on forming complexes. Two systems exhibiting EEC show a correlation between calorimetric entropies and local mobilities, interpreted to mean conformational control of the binding entropy/free energy. However, a substantial contribution from solvation gives the same effect, as a consequence of a structural link between the amount of bound water and the protein flexibility. Only by assuming substantial changes in solvation-an intrinsically compensatory process-can a more complete understanding of EEC be obtained. Faced with such large, and compensating, changes in the enthalpies and entropies of binding, the best approach to engineering elevated affinities must be through the addition of ionic links, as they generate increased entropy without affecting the enthalpy.

  12. Enthalpies of Dissolution of Crystalline Naproxen Sodium in Water and Potassium Hydroxide Aqueous Solutions at 298 K

    NASA Astrophysics Data System (ADS)

    Lytkin, A. I.; Chernikov, V. V.; Krutova, O. N.; Bychkova, S. A.; Volkov, A. V.; Skvortsov, I. A.

    2018-03-01

    The enthalpies of dissolution of crystalline naproxen sodium in water and aqueous solutions of KOH at 298.15 K are measured by direct calorimetric means in a wide range of concentrations. The acid-base properties of naproxen sodium at ionic strength I 0 and I = 0.1 (KNO3) and a temperature of 298.15 K are studied by spectrophotometric means. The concentration and thermodynamic dissociation constants are determined. The standard enthalpies of the formation of naproxen sodium and the products of its dissociation in aqueous solution are calculated.

  13. Comparison of the Mineral Content of Tap Water and Bottled Waters

    PubMed Central

    Azoulay, Arik; Garzon, Philippe; Eisenberg, Mark J

    2001-01-01

    OBJECTIVES Because of growing concern that constituents of drinking water may have adverse health effects, consumption of tap water in North America has decreased and consumption of bottled water has increased. Our objectives were to 1) determine whether North American tap water contains clinically important levels of calcium (Ca2+), magnesium (Mg2+), and sodium (Na+) and 2) determine whether differences in mineral content of tap water and commercially available bottled waters are clinically important. DESIGN We obtained mineral analysis reports from municipal water authorities of 21 major North American cities. Mineral content of tap water was compared with published data regarding commercially available bottled waters and with dietary reference intakes (DRIs). MEASUREMENTS AND MAIN RESULTS Mineral levels varied among tap water sources in North America and among bottled waters. European bottled waters generally contained higher mineral levels than North American tap water sources and North American bottled waters. For half of the tap water sources we examined, adults may fulfill between 8% and 16% of their Ca2+ DRI and between 6% and 31% of their Mg2+ DRI by drinking 2 liters per day. One liter of most moderate mineralization European bottled waters contained between 20% and 58% of the Ca2+ DRI and between 16% and 41% of the Mg2+ DRI in adults. High mineralization bottled waters often contained up to half of the maximum recommended daily intake of Na+. CONCLUSION Drinking water sources available to North Americans may contain high levels of Ca2+, Mg2+, and Na+ and may provide clinically important portions of the recommended dietary intake of these minerals. Physicians should encourage patients to check the mineral content of their drinking water, whether tap or bottled, and choose water most appropriate for their needs. PMID:11318912

  14. Enthalpy Landscape Dictates the Irradiation-Induced Disordering of Quartz

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Krishnan, N. M. Anoop; Wang, Bu; Yu, Yingtian

    Here, under irradiation, minerals tend to experience an accumulation of structural defects, ultimately leading to a disordered atomic network. Despite the critical importance of understanding and predicting irradiation-induced damage, the physical origin of the initiation and saturation of defects remains poorly understood. Here, based on molecular dynamics simulations of α-quartz, we show that the topography of the enthalpy landscape governs irradiation-induced disordering. Specifically, we show that such disordering differs from that observed upon vitrification in that, prior to saturation, irradiated quartz accesses forbidden regions of the enthalpy landscape, i.e., those that are inaccessible by simply heating and cooling. Furthermore, wemore » demonstrate that damage saturates when the system accesses a local region of the enthalpy landscape corresponding to the configuration of an allowable liquid. At this stage, a sudden decrease in the heights of the energy barriers enhances relaxation, thereby preventing any further accumulation of defects and resulting in a defect-saturated disordered state.« less

  15. Enthalpy Landscape Dictates the Irradiation-Induced Disordering of Quartz

    DOE PAGES

    Krishnan, N. M. Anoop; Wang, Bu; Yu, Yingtian; ...

    2017-07-28

    Here, under irradiation, minerals tend to experience an accumulation of structural defects, ultimately leading to a disordered atomic network. Despite the critical importance of understanding and predicting irradiation-induced damage, the physical origin of the initiation and saturation of defects remains poorly understood. Here, based on molecular dynamics simulations of α-quartz, we show that the topography of the enthalpy landscape governs irradiation-induced disordering. Specifically, we show that such disordering differs from that observed upon vitrification in that, prior to saturation, irradiated quartz accesses forbidden regions of the enthalpy landscape, i.e., those that are inaccessible by simply heating and cooling. Furthermore, wemore » demonstrate that damage saturates when the system accesses a local region of the enthalpy landscape corresponding to the configuration of an allowable liquid. At this stage, a sudden decrease in the heights of the energy barriers enhances relaxation, thereby preventing any further accumulation of defects and resulting in a defect-saturated disordered state.« less

  16. Geochemical study of the Sakalol-Harralol geothermal field (Republic of Djibouti): Evidences of a low enthalpy aquifer between Manda-Inakir and Asal rift settings

    NASA Astrophysics Data System (ADS)

    Awaleh, Mohamed Osman; Boschetti, Tiziano; Soubaneh, Youssouf Djibril; Baudron, Paul; Kawalieh, Ali Dirir; Dabar, Omar Assowe; Ahmed, Moussa Mahdi; Ahmed, Samaleh Idriss; Daoud, Mohamed Ahmed; Egueh, Nima Moussa; Mohamed, Jalludin

    2017-02-01

    Eighty-six sodium bicarbonate to sodium chloride hot springs and four water wells in the Tadjourah Region of Djibouti were investigated for major, minor (B, Br, F, Sr, Li) chemistry and isotope composition of water and dissolved components (87Sr/86Sr, 11B/10B, 13C/12C and 14C of DIC, 34S/32S and 18O/16O of sulfate). The deep saline Na-Cl reservoir at 143 °C shows affinity with the shallow geothermal water from the "active" Asal rift. Asal water is a diluted and recycled seawater component with the major cation composition obliterated by equilibration with Stratoid basalt. Locally, the deep reservoir is differentiated in term of recharge, and re-equilibration with rocks and mixing. In particular, two spring groups reveal contributions from evaporites typical of the "passive" graben setting of the Afar. A model on 34S/32S and 18O/16O demonstrates the isotope imprint of magmatic SO2 disproportionation on dissolved and solid sulfate, whose values probably persists in a sedimentary environment without trace of seawater. On the other hand a seawater signature, modified by mixing and secondary fractionation effects, is partially maintained according to the boron isotope composition (up to + 27.4‰). Temperature estimation in low-enthalpy geothermal reservoirs is notoriously difficult, especially where mixing with fluids of differing genesis and/or conduction cooling take place. From a geothermometric point of view, the multi-method approach followed in this study (up-to-date theoretical and thermodynamic equations, ad-hoc silica geothermometers inferred from local rocks, checking of the results on a 18Oαsulfate-water vs. temperature diagram) provides some insights and perspectives on how to tackle the problem. Table S2. Sampling locations, T, pH, EC, TDS and hydrochemical types of the sampled waters. Table S3. Chemical analyses of thermal and cold waters from Sakalaol-Haralol geothermal field. Table S4. Mineral saturation indices of SHGF hot springs waters calculated

  17. Enthalpy of sublimation as measured using a silicon oscillator

    NASA Astrophysics Data System (ADS)

    Shakeel, Hamza; Pomeroy, J. M.

    In this study, we report the enthalpy of sublimation of common gases (nitrogen, oxygen, argon, carbon dioxide, neon, krypton, xenon, and water vapor) using a large area silicon oscillator with a sub-ng (~0.027 ng/cm2) mass sensitivity. The double paddle oscillator design enables high frequency stability (17 ppb) at cryogenic temperatures and provides a consistent technique for enthalpy measurements. The enthalpies of sublimation are derived from the rate of mass loss during programmed thermal desorption and are detected as a change in the resonance frequency of the self-tracking oscillator. These measured enthalpy values show excellent agreement with the accepted literature values.

  18. Recovery of water and minerals from shale gas produced water by membrane distillation crystallization.

    PubMed

    Kim, Junghyun; Kim, Jungwon; Hong, Seungkwan

    2018-02-01

    Shale gas produced water (SGPW) treatment imposes greater technical challenges because of its high concentration of various contaminants. Membrane distillation crystallization (MDC) has a great potential to manage SGPW since it is capable of recovering both water and minerals at high rates, up to near a zero liquid discharge (ZLD) condition. To evaluate the feasibility of MDC for SGPW treatment, MDC performance indicators, such as water recovery rate, solid production rate (SPR) and specific energy consumption (SEC), were systematically investigated, to our knowledge for the first time, by using actual SGPW from Eagle Ford Shale (USA). The main operating parameters including feed cross-flow velocity (CFV) and crystallization temperature (T Cr ) were optimized by performing a series of MDC experiments. The results reported that water and minerals were effectively recovered with 84% of recovery rate and 2.72 kg/m 2 day of SPR under respective optimal operating conditions. Furthermore, the scale mechanism was firstly identified as limiting factor for MDC performance degradation. Lastly, SEC of MDC was estimated to be as low as 28.2 kWh/m 3 under ideal optimal operating conditions. Our experimental observations demonstrated that MDC could sustainably and effectively recover water and mineral with low energy consumption from SGPW by optimizing operating condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The CPA Equation of State and an Activity Coefficient Model for Accurate Molar Enthalpy Calculations of Mixtures with Carbon Dioxide and Water/Brine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Myint, P. C.; Hao, Y.; Firoozabadi, A.

    2015-03-27

    Thermodynamic property calculations of mixtures containing carbon dioxide (CO 2) and water, including brines, are essential in theoretical models of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many models for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental data [1]. In this report, we recommend two different models for enthalpy calculations: the CPA equation of state by Li and Firoozabadi [2], and the CO 2 activity coefficient model by Duanmore » and Sun [3]. We show that the CPA equation of state, which has been demonstrated to provide good agreement with density and solubility data, also accurately calculates molar enthalpies of pure CO 2, pure water, and both CO 2-rich and aqueous (H 2O-rich) mixtures of the two species. It is applicable to a wider range of conditions than the Spycher and Pruess model. In aqueous sodium chloride (NaCl) mixtures, we show that Duan and Sun’s model yields accurate results for the partial molar enthalpy of CO 2. It can be combined with another model for the brine enthalpy to calculate the molar enthalpy of H 2O-CO 2-NaCl mixtures. We conclude by explaining how the CPA equation of state may be modified to further improve agreement with experiments. This generalized CPA is the basis of our future work on this topic.« less

  20. [The combined action of drinking mineral water and low-intensity electromagnetic radiation under the immobilization stress conditions (an experimental study)].

    PubMed

    Korolev, Yu N; Bobrovnitsky, I P; Geniatulina, M S; Mikhailik, L V; Nikulina, L A; Bobkova, A S; Yakovlev, M Yu

    2015-01-01

    The present study carried out on white male rats in experiments with the use of biochemical, radioimmunological, and electron- microscopic methods. It was shown that the combined treatment with potable mineral water (MV) and low-intensity electromagnetic radiation (LIEMR) of ultrahigh frequency (power density less than 1 pW/cm2, the frequency about 1000 MHz) facilitated the activation of metabolic and intracellular regenerative processes in the liver and testes. One of the advantages of the combined application of MV and LIEMR over the single-factor treatment manifested itself as the weakening of stress reactions, the increase in the frequency of the plastic processes, and the more harmonious development of different forms of intracellular regeneration. The results of the study provide a deeper insight ino the mechanisms underlying the combined actions of drinking mineral water and low-intensity electromagnetic radiation; also, they justify the application of these factors for the protection of the reproductive system and the entire body from stress-induced disorders.

  1. On-line Differential Thermal Isotope Analysis: A New Method for Measuring Oxygen and Hydrogen Isotopes of Hydration Water in Minerals

    NASA Astrophysics Data System (ADS)

    Bauska, T.; Hodell, D. A.; Walters, G.

    2016-12-01

    Oxygen (16O,17O,18O) and hydrogen (H,D) isotopes of hydration water in minerals provide a rich source of information about the conditions under which hydrated minerals form on Earth and other planetary bodies (e.g. Mars). We have developed a new method for measuring different types of bonded water (e.g., molecular, hydroxyl) contained in hydrated minerals by coupling a thermal gravimeter (TG) and a cavity ringdown laser spectrometer (CRDS). The method involves step heating a mineral sample, precisely measuring the weight loss and enthalpy as the sample undergoes dehydration and dehydroxylation, whilst simultaneously determining the oxygen and hydrogen isotopes of the water vapor evolved from the mineral sample by cavity ring-down laser spectroscopy (CRDS). Nitrogen carrier gas is used to transfer the sample from the TG to the CRDS via a heated line and interface box. The interface includes the capability of (i) cryogenic trapping discrete types of water for samples containing small amounts of water; (ii) injecting small quantities of water of known isotopic value for calibration; and (iii) converting volatile organic compounds to nascent amounts of water using a catalyst. The CRDS continually measures water vapor concentration in the optical cavity and hydrogen and oxygen isotope ratios. Isotopic values are calculated by integrating the product of the water amount and its isotopic value for the separated peaks after correcting for background. Precision of the method was estimated by comparing isotope results of total water for gypsum measured by DTIA with our conventional method of extraction and analysis (Gázquez et al., 2015. Rapid Communications in Mass Spectrometry, 29, 1997-2006). Errors for the isotopic values of total hydration water vary between ±0.08 and ±0.34 ‰ for δ18O and between ±0.16 and ±0.86 ‰ for δD. We demonstrate the application of the DTIA method to a variety of hydrous minerals and mineraloids including gypsum, clays, and amorphous

  2. Heat Effect of the Protonation of Glycine and the Enthalpies of Resolvation of Participating Chemical Species in Water-Dimethylsulfoxide Solvent Mixtures

    NASA Astrophysics Data System (ADS)

    Isaeva, V. A.; Sharnin, V. A.

    2018-02-01

    Enthalpies of the protonation of glycine in water‒dimethylsulfoxide (DMSO) mixed solvents are determined calorimetrically in the range of DMSO mole fractions of 0.0 to 0.9, at T = 298.15 K and an ionic strength μ = 0.3 (NaClO4). It is established that the protonation of glycine becomes more exothermic with an increasing mole fraction of DMSO, and the enthalpies of resolvation of glycine and glycinium ions in water‒DMSO solvent mixtures are calculated. It is shown that the small changes in the enthalpy of protonation observed at low mole fractions of DMSO are caused by the contributions from the solvation of proton and protonated glycine cancelling each other out. The enthalpy term of the Gibbs energy of the reaction leading to the formation of glycinium ion is estimated along with the enthalpy of resolvation of the reacting species in the water‒DMSO mixed solvent.

  3. Survival of human pathogenic bacteria in different types of natural mineral water.

    PubMed

    Serrano, Concepción; Romero, Margarita; Alou, Luis; Sevillano, David; Corvillo, Iluminada; Armijo, Francisco; Maraver, Francisco

    2012-09-01

    The aim of this study was to determine the survival of human pathogens (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) in five natural mineral waters (NMWs) with different properties and mineralization levels. Five NMWs from four Spanish spas with different dry residue at 110 °C were used: A = 76,935 mg/L; B = 1,827 mg/L; C = 808.4 mg/L; D = 283.8 mg/L; and E = 170.4 mg/L. An initial inoculum of 1 × 10(6) colony forming units (cfu)/mL was used for survival studies. Distilled water, chlorinated tap water and Mueller-Hinton broth were used as controls. Colony counts in all different waters were lower than those achieved with Mueller-Hinton broth over all incubation periods. A direct effect between the bacterial survival and the level of mineralization water was observed. The NMW E with low mineralization level along with the radioactive properties showed the highest antibacterial activity among all NMWs.

  4. Mineral water or tap water? An endless debate.

    PubMed

    De Giglio, O; Quaranta, A; Lovero, G; Caggiano, G; Montagna, M T

    2015-01-01

    The consumption of mineral water has been increasing because of the frequent and unjustified reports of the water supply contamination. However some authors have shown that bottled waters are not always better than tap water. Mineral waters are more palatable for organoleptic characteristic because, being pure at source, they do not undergo disinfection treatments and are sometimes enriched with CO2. In fact, they are characterized by their microbial facies subject to changes during the production cycle which can contribute to their contamination. It is necessary to provide people with the tools necessary to operate a critical choice of the type of water to be consumed not exclusively for their organoleptic characteristics or marketing strategies.

  5. Low water contents in diamond mineral inclusions: Proto-genetic origin in a dry cratonic lithosphere

    NASA Astrophysics Data System (ADS)

    Taylor, Lawrence A.; Logvinova, Alla M.; Howarth, Geoffrey H.; Liu, Yang; Peslier, Anne H.; Rossman, George R.; Guan, Yunbin; Chen, Yang; Sobolev, Nikolay V.

    2016-01-01

    The mantle is the major reservoir of Earth's water, hosted within Nominally Anhydrous Minerals (NAMs) (e.g., Bell and Rossman, 1992; Peslier et al., 2010; Peslier, 2010; Nestola and Smyth, 2015), in the form of hydrogen bonded to the silicate's structural oxygen. From whence cometh this water? Is the water in these minerals representative of the Earth's primitive upper mantle or did it come from melting events linked to crustal formation or to more recent metasomatic/re-fertilization events? During diamond formation, NAMs are encapsulated at hundreds of kilometers depth within the mantle, thereby possibly shielding and preserving their pristine water contents from re-equilibrating with fluids and melts percolating through the lithospheric mantle. Here we show that the NAMs included in diamonds from six locales on the Siberian Craton contain measurable and variable H2O concentrations from 2 to 34 parts per million by weight (ppmw) in olivine, 7 to 276 ppmw in clinopyroxene, and 11-17 ppmw in garnets. Our results suggest that if the inclusions were in equilibrium with the diamond-forming fluid, the water fugacity would have been unrealistically low. Instead, we consider the H2O contents of the inclusions, shielded by diamonds, as pristine representatives of the residual mantle prior to encapsulation, and indicative of a protogenetic origin for the inclusions. Hydrogen diffusion in the diamond does not appear to have modified these values significantly. The H2O contents of NAMs in mantle xenoliths may represent some later metasomatic event(s), and are not always representative of most of the continental lithospheric mantle. Results from the present study also support the conclusions of Peslier et al. (2010) and Novella et al. (2015) that the dry nature of the SCLM of a craton may provide stabilization of its thickened continental roots.

  6. [Fundamental study on effect of high-mineral drinking water for osteogenesis in calciprivia ovariectomized rats].

    PubMed

    Ogata, Fumihiko; Nagai, Noriaki; Ito, Yoshimasa; Kawasaki, Naohito

    2014-01-01

    Since osteoporosis is a major public health problem in Japan, it is important to clarify the effect of high-mineral drinking water consumption on osteogenesis. Therefore, in this study, we investigated the relationship between high-mineral drinking water consumption and osteogenesis in ovariectomized rats that received a low-calcium diet and purified water (PW group) or a low-calcium diet and high-mineral drinking water (CR group). High-mineral drinking water affected the rats' body weight. After 3 months, the bone density of the CR group was higher than that of the PW group (p<0.05). Furthermore, the CR group showed a decrease in the amount of calcium in the bones after 3 months. These results suggest that high-mineral drinking water contributes to the maintenance of bone density and not to the amount of calcium in bone. On the other hand, serum alkaline phosphatase levels in the PW group at 3 months were higher than those in the CR group, which indicates that the blood concentration of calcium in the CR group was maintained. Moreover, the amount of magnesium in the bones and the blood concentration of magnesium in the CR group after 3 months were higher than the corresponding values in the PW group. These results suggest that consumption of high-mineral drinking water could be beneficial for osteogenesis (i.e., for maintaining bone quantity).

  7. Modeling CO2-Water-Mineral Wettability and Mineralization for Carbon Geosequestration.

    PubMed

    Liang, Yunfeng; Tsuji, Shinya; Jia, Jihui; Tsuji, Takeshi; Matsuoka, Toshifumi

    2017-07-18

    Carbon dioxide (CO 2 ) capture and storage (CCS) is an important climate change mitigation option along with improved energy efficiency, renewable energy, and nuclear energy. CO 2 geosequestration, that is, to store CO 2 under the subsurface of Earth, is feasible because the world's sedimentary basins have high capacity and are often located in the same region of the world as emission sources. How CO 2 interacts with the connate water and minerals is the focus of this Account. There are four trapping mechanisms that keep CO 2 in the pores of subsurface rocks: (1) structural trapping, (2) residual trapping, (3) dissolution trapping, and (4) mineral trapping. The first two are dominated by capillary action, where wettability controls CO 2 and water two-phase flow in porous media. We review state-of-the-art studies on CO 2 /water/mineral wettability, which was found to depend on pressure and temperature conditions, salt concentration in aqueous solutions, mineral surface chemistry, and geometry. We then review some recent advances in mineral trapping. First, we show that it is possible to reproduce the CO 2 /water/mineral wettability at a wide range of pressures using molecular dynamics (MD) simulations. As the pressure increases, CO 2 gas transforms into a supercritical fluid or liquid at ∼7.4 MPa depending on the environmental temperature. This transition leads to a substantial decrease of the interfacial tension between CO 2 and reservoir brine (or pure water). However, the wettability of CO 2 /water/rock systems depends on the type of rock surface. Recently, we investigated the contact angle of CO 2 /water/silica systems with two different silica surfaces using MD simulations. We found that contact angle increased with pressure for the hydrophobic (siloxane) surface while it was almost constant for the hydrophilic (silanol) surface, in excellent agreement with experimental observations. Furthermore, we found that the CO 2 thin films at the CO 2 -hydrophilic

  8. Adsorption of organic ligands on low surface charge clay minerals: the composition in the aqueous interface region.

    PubMed

    Jelavić, S; Stipp, S L S; Bovet, N

    2018-06-27

    An understanding of the mechanisms that control the adsorption of organic molecules on clay minerals is of interest in several branches of science and industry. Oil production using low salinity injection fluids can increase yields by as much as 40% over standard injection with seawater or formation water. The mechanism responsible for the low salinity response is still debated, but one hypothesis is a change in pore surface wettability. Organic contamination in soil and drinking water aquifers is a challenge for municipal water suppliers and for agriculture. A better understanding is needed for how mineral species, solution composition and pH affect the desorption of low molecular weight organic ligands from clay minerals and consequently their wettability. We used X-ray photoelectron spectroscopy under cryogenic conditions to investigate the in situ composition in the mineral-solution interface region in a series of experiments with a range of pH and ion concentrations. We demonstrate that both chlorite and kaolinite release organic molecules under conditions relevant for low salinity water flooding. This release increases with a higher solution pH but is only slightly affected by the character of the organic ligand. This is consistent with the observation that low salinity enhanced oil recovery correlates with the presence of chlorite and kaolinite. Our results indicate that the pore surface charge and salinity of formation water and injection fluids are key parameters in determining the low salinity response. In general, our results imply that clay mineral surface charge influences the composition in the interface through an affinity for organic molecules.

  9. Evaluation of minerals content of drinking water in Malaysia.

    PubMed

    Azlan, Azrina; Khoo, Hock Eng; Idris, Mohd Aizat; Ismail, Amin; Razman, Muhammad Rizal

    2012-01-01

    The drinking and mineral water samples obtained from different geographical locations had concentrations of the selected minerals lower than the standard limits, except for manganese, arsenic, and fluoride. The concentrations of manganese and arsenic in two mineral water samples were slightly higher than the standard international recommended limits. One mineral water sample had a fluoride concentration higher than the standard limits, whereas manganese was not detected in nine drinking and mineral water samples. Most of the selected minerals found in the tap water samples were below the international standard limits, except for iron and manganese. The concentrations of iron and manganese in the tap water samples were higher than the standard limits, which were obtained from one and three of the studied locations, respectively. The potable water obtained from various manufacturers and locations in Peninsular Malaysia is safe for consumption, as the minerals concentrations were below the standard limits prescribed by the Malaysian Food Regulations of 1985. The data obtained may also provide important information related to daily intake of these minerals from drinking water.

  10. Evaluation of Minerals Content of Drinking Water in Malaysia

    PubMed Central

    Azlan, Azrina; Khoo, Hock Eng; Idris, Mohd Aizat; Ismail, Amin; Razman, Muhammad Rizal

    2012-01-01

    The drinking and mineral water samples obtained from different geographical locations had concentrations of the selected minerals lower than the standard limits, except for manganese, arsenic, and fluoride. The concentrations of manganese and arsenic in two mineral water samples were slightly higher than the standard international recommended limits. One mineral water sample had a fluoride concentration higher than the standard limits, whereas manganese was not detected in nine drinking and mineral water samples. Most of the selected minerals found in the tap water samples were below the international standard limits, except for iron and manganese. The concentrations of iron and manganese in the tap water samples were higher than the standard limits, which were obtained from one and three of the studied locations, respectively. The potable water obtained from various manufacturers and locations in Peninsular Malaysia is safe for consumption, as the minerals concentrations were below the standard limits prescribed by the Malaysian Food Regulations of 1985. The data obtained may also provide important information related to daily intake of these minerals from drinking water. PMID:22649292

  11. Effect of Minerals on Intestinal IgA Production Using Deep Sea Water Drinks.

    PubMed

    Shiraishi, Hisashi; Fujino, Maho; Shirakawa, Naoki; Ishida, Nanao; Funato, Hiroki; Hirata, Ayumu; Abe, Noriaki; Iizuka, Michiro; Jobu, Kohei; Yokota, Junko; Miyamura, Mitsuhiko

    2017-01-01

    Minerals are essential for life, as they are a vital part of protein constituents, enzyme cofactors, and other components in living organisms. Deep sea water is characterized by its cleanliness and stable low temperature, and its possible health- and medical benefits are being studied. However, no study has yet evaluated the physical properties of the numerous commercially available deep sea water products, which have varying water sources and production methods. We analyzed these products' mineral content and investigated their effect on living organism, focusing on immune functions, and investigated the relation between physiological immunoactivities and mineral intake. We qualitatively analyzed the mineral compositions of the deep sea water drinks and evaluated the drinks' physical properties using principal component analysis, a type of multivariate analysis, of their mineral content. We create an iron and copper-deficient rat model and administered deep sea water drinks for 8 weeks. We then measured their fecal immunoglobulin A (IgA) to evaluate immune function. Principal component analysis suggested that physical properties of deep sea water drinks could be determined by their sources. Administration of deep sea water drinks increased fecal IgA, thus tending to stimulate immune function, but the extent of this effect varied by drink. Of the minerals contained in deep sea water, iron showed positive correlations with the fecal IgA. The principal component analysis used in this study is suitable for evaluating deep sea water containing many minerals, and our results form a useful basis for comparative evaluations of deep sea water's bioactivity.

  12. High enthalpy hypersonic boundary layer flow

    NASA Technical Reports Server (NTRS)

    Yanow, G.

    1972-01-01

    A theoretical and experimental study of an ionizing laminar boundary layer formed by a very high enthalpy flow (in excess of 12 eV per atom or 7000 cal/gm) with allowance for the presence of helium driver gas is described. The theoretical investigation has shown that the use of variable transport properties and their respective derivatives is very important in the solution of equilibrium boundary layer equations of high enthalpy flow. The effect of low level helium contamination on the surface heat transfer rate is minimal. The variation of ionization is much smaller in a chemically frozen boundary layer solution than in an equilibrium boundary layer calculation and consequently, the variation of the transport properties in the case of the former was not essential in the integration. The experiments have been conducted in a free piston shock tunnel, and a detailed study of its nozzle operation, including the effects of low levels of helium driver gas contamination has been made. Neither the extreme solutions of an equilibrium nor of a frozen boundary layer will adequately predict surface heat transfer rate in very high enthalpy flows.

  13. Minerals leached into drinking water from rubber stoppers.

    PubMed

    Kennedy, B W; Beal, T S

    1991-06-01

    Drinking water and its delivery system are potential sources of variation in animal research. Concern arose that rubber stoppers used to cork water bottles might be a source of some nutritionally required minerals which could leach into drinking water. Six types of stoppers, each having different compositions, were cleaned with stainless-steel sipper tubes inserted into them and attached to polypropylene bottles filled with either deionized water (pH 4.5) or acidified-deionized water (pH 2.5). After six days of contact, water levels of copper, magnesium, iron, manganese, zinc, chromium, and selenium were determined by atomic absorption spectroscopy. Additionally, three of the stopper types were analyzed for mineral content. Minerals were present in both stoppers and drinking water. Acidified-deionized water generally leached minerals from the stoppers than did deionized water. The black stopper which is commonly used in animal facilities contained and leached measurable levels of some minerals, but it still can be recommended for typical animal husbandry uses, although other types of stoppers would be more suitable for specific nutritional and toxicologic studies.

  14. 2D joint inversion of dc and scalar audio-magnetotelluric data in the evaluation of low enthalpy geothermal fields

    NASA Astrophysics Data System (ADS)

    Monteiro Santos, Fernando A.; Afonso, António R. Andrade; Dupis, André

    2007-03-01

    Audio-magnetotelluric (AMT) and resistivity (dc) surveys are often used in environmental, hydrological and geothermal evaluation. The separate interpretation of those geophysical data sets assuming two-dimensional models frequently produces ambiguous results. The joint inversion of AMT and dc data is advocated by several authors as an efficient method for reducing the ambiguity inherent to each of those methods. This paper presents results obtained from the two-dimensional joint inversion of dipole-dipole and scalar AMT data acquired in a low enthalpy geothermal field situated in a graben. The joint inverted models show a better definition of shallow and deep structures. The results show that the extension of the benefits using joint inversion depends on the number and spacing of the AMT sites. The models obtained from experimental data display a low resistivity zone (<20 Ω m) in the central part of the graben that was correlated with the geothermal reservoir. The resistivity distribution models were used to estimate the distribution of the porosity in the geothermal reservoir applying two different approaches and considering the clay minerals effect. The results suggest that the maximum porosity of the reservoir is not uniform and might be in the range of 12% to 24%.

  15. Some physicochemical aspects of water-soluble mineral flotation.

    PubMed

    Wu, Zhijian; Wang, Xuming; Liu, Haining; Zhang, Huifang; Miller, Jan D

    2016-09-01

    Some physicochemical aspects of water-soluble mineral flotation including hydration phenomena, associations and interactions between collectors, air bubbles, and water-soluble mineral particles are presented. Flotation carried out in saturated salt solutions, and a wide range of collector concentrations for effective flotation of different salts are two basic aspects of water-soluble mineral flotation. Hydration of salt ions, mineral particle surfaces, collector molecules or ions, and collector aggregates play an important role in water-soluble mineral flotation. The adsorption of collectors onto bubble surfaces is suggested to be the precondition for the association of mineral particles with bubbles. The association of collectors with water-soluble minerals is a complicated process, which may include the adsorption of collector molecules or ions onto such surfaces, and/or the attachment of collector precipitates or crystals onto the mineral surfaces. The interactions between the collectors and the minerals include electrostatic and hydrophobic interactions, hydrogen bonding, and specific interactions, with electrostatic and hydrophobic interactions being the common mechanisms. For the association of ionic collectors with minerals with an opposite charge, electrostatic and hydrophobic interactions could have a synergistic effect, with the hydrophobic interactions between the hydrophobic groups of the previously associated collectors and the hydrophobic groups of oncoming collectors being an important attractive force. Association between solid particles and air bubbles is the key to froth flotation, which is affected by hydrophobicity of the mineral particle surfaces, surface charges of mineral particles and bubbles, mineral particle size and shape, temperature, bubble size, etc. The use of a collector together with a frother and the use of mixed surfactants as collectors are suggested to improve flotation. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Discharge, water temperature, and water quality of Warm Mineral Springs, Sarasota County, Florida: A retrospective analysis

    USGS Publications Warehouse

    Metz, Patricia A.

    2016-09-27

    characterized by a slight-green color, with varying water clarity, low dissolved oxygen (indicative of deep groundwater), and a hydrogen sulfide odor. Water-quality samples detected ammonium-nitrogen and nitrates, but at low concentrations. The drinking water standard for nitrate adopted by the U.S. Environmental Protection Agency is 10 milligrams per liter, measured as nitrogen. Water samples collected at spring vents by divers on April 29, 2015, had concentrations of 0.9 milligram per liter nitrate-nitrogen at vent A and 0.04–0.05 milligram per liter at vents B, C, and D. Typically, the water clarity is highest in the morning (about 30 feet Secchi depth) and often decreases throughout the day.Analysis of existing data provided some insight into the hydrologic processes affecting Warm Mineral Springs; however, data have been sparsely and discontinuously collected since the 1940s. Continuous monitoring of hydrologic characteristics such as discharge, water temperature, specific conductance, and water-quality indicators, such as nitrate and turbidity (water clarity), would be valuable for monitoring and development of models of spring discharge and water quality. In addition, water samples could be analyzed for isotopic tracers, such as strontium, and the results used to identify and quantify the sources of groundwater that discharge at Warm Mineral Springs. Groundwater flow/transport models could be used to evaluate the sensitivity of the quality and quantity of water flowing from Warm Mineral Springs to changes in climate, aquifer levels, and water use.

  17. Enthalpy generation from mixing in hohlraum-driven targets

    NASA Astrophysics Data System (ADS)

    Amendt, Peter; Milovich, Jose

    2016-10-01

    The increase in enthalpy from the physical mixing of two initially separated materials is analytically estimated and applied to ICF implosions and gas-filled hohlraums. Pressure and temperature gradients across a classical interface are shown to be the origin of enthalpy generation from mixing. The amount of enthalpy generation is estimated to be on the order of 100 Joules for a 10 micron-scale annular mixing layer between the solid deuterium-tritium fuel and the undoped high-density carbon ablator of a NIF-scale implosion. A potential resonance is found between the mixing layer thickness and gravitational (Cs2/ g) and temperature-gradient scale lengths, leading to elevated enthalpy generation. These results suggest that if mixing occurs in current capsule designs for the National Ignition Facility, the ignition margin may be appreciably eroded by the associated enthalpy of mixing. The degree of enthalpy generation from mixing of high- Z hohlraum wall material and low- Z gas fills is estimated to be on the order of 100 kJ or more for recent NIF-scale hohlraum experiments, which is consistent with the inferred missing energy based on observed delays in capsule implosion times. Work performed under the auspices of Lawrence Livermore National Security, LLC (LLNS) under Contract No. DE-AC52-07NA27344.

  18. Hydrogeochemical tracing of mineral water in Jingyu County, Northeast China.

    PubMed

    Yan, Baizhong; Xiao, Changlai; Liang, Xiujuan; Wu, Shili

    2016-02-01

    The east Jilin Province in China, Jingyu County has been explored as a potential for enriching mineral water. In order to assess the water quality and quantity, it is of crucial importance to investigate the origin of the mineral water and its flow paths. In this study, eighteen mineral springs were sampled in May and September of 2012, May and September of 2013, and May 2014 and the environment, evolvement, and reaction mechanism of mineral water formation were analysed by hydrochemical data analysis, geochemical modelling and multivariate statistical analysis. The results showed that the investigated mineral water was rich in calcium, magnesium, potassium, sodium, bicarbonate, chloride, sulphate, fluoride, nitrate, total iron, silicate, and strontium, and mineral water ages ranged from 11.0 to more than 61.0 years. The U-shape contours of the mineral ages indicate a local and discrete recharge. The mineral compositions of the rocks were olivine, potassium feldspar, pyroxene, albite, and anorthite and were under-saturated in the mineral water. The origin of mineral water was from the hydrolysis of basalt minerals under a neutral to slightly alkaline and CO2-rich environment.

  19. [The characteristics of the use of low-mineralization sodium chloride mineral water in the rehabilitative treatment of patients with the most common diseases of the internal organs].

    PubMed

    Babov, K D; Belichenko, T A; Nikipelova, E M; Serebrina, L A

    1999-01-01

    The paper describes some therapeutic aspects of sodium chloride mineral water from the springs of Mirgorod (a balneological resort in Ukraine). Methodological approaches to the treatment of patients with most common visceral disease with bottled mineral Mirgorod water are outlined.

  20. 43 CFR 3594.5 - Minerals soluble in water; brines; minerals taken in solution.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Minerals soluble in water; brines; minerals taken in solution. 3594.5 Section 3594.5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) SOLID MINERALS (OTHER THAN COAL) EXPLORATION AND...

  1. Hydration of dimethyldodecylamine-N-oxide: enthalpy and entropy driven processes.

    PubMed

    Kocherbitov, Vitaly; Söderman, Olle

    2006-07-13

    Dimethyldodecylamine-N-oxide (DDAO) has only one polar atom that is able to interact with water. Still, this surfactant shows very hydrophilic properties: in mixtures with water, it forms normal liquid crystalline phases and micelles. Moreover, there is data in the literature indicating that the hydration of this surfactant is driven by enthalpy while other studies show that hydration of surfactants and lipids typically is driven by entropy. Sorption calorimetry allows resolving enthalpic and entropic contributions to the free energy of hydration at constant temperature and thus directly determines the driving forces of hydration. The results of the present sorption calorimetric study show that the hydration of liquid crystalline phases of DDAO is driven by entropy, except for the hydration of the liquid crystalline lamellar phase which is co-driven by enthalpy. The exothermic heat effect of the hydration of the lamellar phase arises from formation of strong hydrogen bonds between DDAO and water. Another issue is the driving forces of the phase transitions caused by the hydration. The sorption calorimetric results show that the transitions from the lamellar to cubic and from the cubic to the hexagonal phase are driven by enthalpy. Transitions from solid phases to the liquid crystalline lamellar phase are entropically driven, while the formation of the monohydrate from the dry surfactant is driven by enthalpy. The driving forces of the transition from the hexagonal phase to the isotropic solution are close to zero. These sorption calorimetric results are in good agreement with the analysis of the binary phase diagram based on the van der Waals differential equation. The phase diagram of the DDAO-water system determined using DSC and sorption calorimetry is presented.

  2. Mineral constituents in water and their significance

    USGS Publications Warehouse

    Dover, T.B.

    1950-01-01

    Pure water does not exist in nature. Because water is a powerful solvent, every drop of rain water carries dissolved or suspended material - dust, pollen, and smoke, as well as the atmospheric gases, oxygen, nitrogen and carbon dioxide. When rain falls, the water running over the rocks and percolating through the soil gathers more and more mineral matter in solution. As the uses to which a water supply may be put depend primarily on its mineral content, information concerning the chemical characteristics of water is of importance to each of us. (available as photostat copy only)

  3. Capacitive Detection of Low-Enthalpy, Higher-Order Phase Transitions in Synthetic and Natural Composition Lipid Membranes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Taylor, Graham J.; Heberle, Frederick A.; Seinfeld, Jason S.

    In-plane lipid organization and phase separation in natural membranes play key roles in regulating many cellular processes. Highly cooperative, first-order phase transitions in model membranes consisting of few lipid components are well understood and readily detectable via calorimetry, densitometry, and fluorescence. However, far less is known about natural membranes containing numerous lipid species and high concentrations of cholesterol, for which thermotropic transitions are undetectable by the above-mentioned techniques. We demonstrate that membrane capacitance is highly sensitive to low-enthalpy thermotropic transitions taking place in complex lipid membranes. Specifically, we measured the electrical capacitance as a function of temperature for droplet interfacemore » bilayer model membranes of increasing compositional complexity, namely, (a) a single lipid species, (b) domain-forming ternary mixtures, and (c) natural brain total lipid extract (bTLE). We observed that, for single-species lipid bilayers and some ternary compositions, capacitance exhibited an abrupt, temperature-dependent change that coincided with the transition detected by other techniques. In addition, capacitance measurements revealed transitions in mixed-lipid membranes that were not detected by the other techniques. Most notably, capacitance measurements of bTLE bilayers indicated a transition at ~38 °C not seen with any other method. Likewise, capacitance measurements detected transitions in some well-studied ternary mixtures that, while known to yield coexisting lipid phases, are not detected with calorimetry or densitometry. These results indicate that capacitance is exquisitely sensitive to low-enthalpy membrane transitions because of its sensitivity to changes in bilayer thickness that occur when lipids and excess solvent undergo subtle rearrangements near a phase transition. Our findings also suggest that heterogeneity confers stability to natural membranes that function near

  4. Capacitive Detection of Low-Enthalpy, Higher-Order Phase Transitions in Synthetic and Natural Composition Lipid Membranes

    DOE PAGES

    Taylor, Graham J.; Heberle, Frederick A.; Seinfeld, Jason S.; ...

    2017-08-15

    In-plane lipid organization and phase separation in natural membranes play key roles in regulating many cellular processes. Highly cooperative, first-order phase transitions in model membranes consisting of few lipid components are well understood and readily detectable via calorimetry, densitometry, and fluorescence. However, far less is known about natural membranes containing numerous lipid species and high concentrations of cholesterol, for which thermotropic transitions are undetectable by the above-mentioned techniques. We demonstrate that membrane capacitance is highly sensitive to low-enthalpy thermotropic transitions taking place in complex lipid membranes. Specifically, we measured the electrical capacitance as a function of temperature for droplet interfacemore » bilayer model membranes of increasing compositional complexity, namely, (a) a single lipid species, (b) domain-forming ternary mixtures, and (c) natural brain total lipid extract (bTLE). We observed that, for single-species lipid bilayers and some ternary compositions, capacitance exhibited an abrupt, temperature-dependent change that coincided with the transition detected by other techniques. In addition, capacitance measurements revealed transitions in mixed-lipid membranes that were not detected by the other techniques. Most notably, capacitance measurements of bTLE bilayers indicated a transition at ~38 °C not seen with any other method. Likewise, capacitance measurements detected transitions in some well-studied ternary mixtures that, while known to yield coexisting lipid phases, are not detected with calorimetry or densitometry. These results indicate that capacitance is exquisitely sensitive to low-enthalpy membrane transitions because of its sensitivity to changes in bilayer thickness that occur when lipids and excess solvent undergo subtle rearrangements near a phase transition. Our findings also suggest that heterogeneity confers stability to natural membranes that function near

  5. Undergraduate Students' Conceptions of Enthalpy, Enthalpy Change and Related Concepts

    ERIC Educational Resources Information Center

    Nilsson, Tor; Niedderer, Hans

    2014-01-01

    Research shows that students have problems understanding thermodynamic concepts and that a gap exists at the tertiary level related to more specific chemistry concepts such as enthalpy. Therefore, the aim of this study is to construct undergraduate students' conceptions of enthalpy, its change and related concepts. Three explorative small-scale…

  6. Mineralizing urban net-zero water treatment: Phase II field ...

    EPA Pesticide Factsheets

    Net-zero water (NZW) systems, or water management systems achieving high recycling rates and low residuals generation so as to avoid water import and export, can also conserve energy used to heat and convey water, while economically restoring local eco-hydrology. However, design and operating experience are extremely limited. The objective of this paper is to present the results of the second phase of operation of an advanced oxidation-based NZW pilot system designed, constructed, and operated for a period of two years, serving an occupied four-person apartment. System water was monitored, either continuously or thrice daily, for routine water quality parameters, minerals, and MicroTox® in-vitro toxicity, and intermittently for somatic and male-specific coliphage, adenovirus, Cryptosporidium, Giardia, emerging organic constituents (non-quantitative), and the Florida drinking water standards. All 115 drinking water standards with the exception of bromate were met in this phase. Neither virus nor protozoa were detected in the treated water, with the exception of measurement of adenovirus genome copies attributed to accumulation of inactive genetic material in hydraulic dead zones. Chemical oxygen demand was mineralized to 90% in treatment. Total dissolved solids were maintained at ∼500 mg/L at steady state, partially through aerated aluminum electrocoagulation. Bromate accumulation is projected to be controlled by aluminum electrocoagulation with separate dispo

  7. Linear adsorption of nonionic organic compounds from water onto hydrophilic minerals: Silica and alumina

    USGS Publications Warehouse

    Su, Y.-H.; Zhu, Y.-G.; Sheng, G.; Chiou, C.T.

    2006-01-01

    To characterize the linear adsorption phenomena in aqueous nonionic organic solute-mineral systems, the adsorption isotherms of some low-molecular- weightnonpolar nonionic solutes (1,2,3-trichlorobenzene, lindane, phenanthrene, and pyrene) and polar nonionic solutes (1,3-dinitrobenzene and 2,4-dinitrotoluene) from single-and binary-solute solutions on hydrophilic silica and alumina were established. Toward this objective, the influences of temperature, ionic strength, and pH on adsorption were also determined. It is found that linear adsorption exhibits low exothermic heats and practically no adsorptive competition. The solute-solid configuration and the adsorptive force consistent with these effects were hypothesized. For nonpolar solutes, the adsorption occurs presumably by London (dispersion) forces onto a water film above the mineral surface. For polar solutes, the adsorption is also assisted by polar-group interactions. The reduced adsorptive forces of solutes with hydrophilic minerals due to physical separation by the water film and the low fractions of the water-film surface covered by solutes offer a theoretical basis for linear solute adsorption, low exothermic heats, and no adsorptive competition. The postulated adsorptive forces are supported by observations that ionic strength or pH poses no effect on the adsorption of nonpolar solutes while it exhibits a significant effect on the uptake of polar solutes. ?? 2006 American Chemical Society.

  8. 43 CFR 3594.5 - Minerals soluble in water; brines; minerals taken in solution.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Minerals soluble in water; brines; minerals taken in solution. 3594.5 Section 3594.5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) SOLID...

  9. 43 CFR 3594.5 - Minerals soluble in water; brines; minerals taken in solution.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Minerals soluble in water; brines; minerals taken in solution. 3594.5 Section 3594.5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) SOLID...

  10. 43 CFR 3594.5 - Minerals soluble in water; brines; minerals taken in solution.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Minerals soluble in water; brines; minerals taken in solution. 3594.5 Section 3594.5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) SOLID...

  11. [The determination of molecular sulphur in Matsesta mineral water and its analog Novonukutskaya mineral water].

    PubMed

    Khutorianskiĭ, V A; Smirnov, A I; Matveev, D A

    2014-01-01

    The method of microcolumn reversed phase high performance liquid chromatography (rp-HPLC) was employed to determine the content of elemental sulphur in mineral waters. The study envisaged the analysis of the samples of sulphide-containing mineral waters Novonukutskaya and Matsesta obtained by the solid phase extraction technique. Based on these data, the authors discuss the origin and the circulation of sulphur in the hydrogen sulphide sources. The elution conditions selected in this study ensured the high-resolution separation of the octasulphur peak from the peaks of allotropic components of the extract whereas the two-wave detection technique allowed to identify the peaks of molecular sulphur.

  12. The rheological effect of water on lower mantle minerals

    NASA Astrophysics Data System (ADS)

    Muir, J.; Brodholt, J. P.

    2017-12-01

    The presence of water in many upper mantle minerals has been shown to have a large effect on their rheology in what is generally known as "hydrolytic weakening". A growing number of studies are finding that incorporating a water dependent rheology into global mantle convection models has a strong effect on global dynamics. However, while there is an abundance of experimental evidence showing that upper mantle minerals deformed under hydrous conditions are significantly weaker than when dry, there is no such experimental evidence for lower mantle minerals. In this study we use DFT methods to calculate the partitioning of water between different sites in lower mantle minerals (bridgmanite, cubic and tetragonal calcium perovskite, ferropericlase and phase H) which allows us to speculate on the effects of water on the rheology and phase stability of lower mantle minerals under various conditions. The effect of water on lower mantle minerals is found to depend strongly upon both water content and temperature. Under typical lower mantle conditions and with reasonable water concentrations (<1000 ppm), water partitions preferentially into bridgmanite but with a mechanism that does not increase the concentration of Mg or Si vacancies in bridgmanite and thus is unlikely to affect its rheology. In cooler conditions, such as in a descending slab, water partitions into calcium perovskite or forms water rich aluminous phases. The presence of water in calcium perovskite has large effects on the preferred phase and can induce multiple phase transitions at varying depths of the mantle depending upon both water content and slab temperature. These transitions are likely to be seismically anomalous and could cause large and characteristic seismic heterogeneity in descending slabs.

  13. Growth Performance, Mineral Digestibility, and Blood Characteristics of Ostriches Receiving Drinking Water Supplemented with Varying Levels of Chelated Trace Mineral Complex.

    PubMed

    Seyfori, Hossein; Ghasemi, Hossein Ali; Hajkhodadadi, Iman; Nazaran, Mohammad Hassan; Hafizi, Maryam

    2018-05-01

    The effects of water supplementation of chelated trace minerals (CTM, which is named Bonzaplex designed with chelate compounds technology) on growth performance, apparent total tract digestibility (ATTD) of minerals, and some blood metabolites, TM, and antioxidant enzyme values in African ostriches were investigated from 8 to 12 months of age. A total of 20 8-month-old ostriches (five birds in five replicate pens) was randomly allocated into one of the following four treatments: (1) control (basal diet + tap water), (2) low CTM (basal diet +100 mg/bird/day CTM powder in tap water), (3) medium CTM (basal diet +1 g/bird/day CTM powder in tap water), and (4) high CTM (basal diet +2 g/bird/day CTM powder in tap water). Compared with control, medium CTM improved (P < 0.05) daily weight gain and ATTD of phosphorous, zinc, and copper in 12-month-old ostriches. Furthermore, the feed conversion ratio was lower, and ATTD of magnesium was higher in the medium- and high-CTM groups than that in the control group (P < 0.05). At the end of the trial, ostriches receiving high-CTM treatment exhibited the lower (P < 0.05) serum triglyceride and very low-density lipoprotein cholesterol concentrations and higher copper levels compared to those of the control treatment. Supplementation of higher amounts of CTM (medium and high CTM) also increased the activity of serum superoxide dismutase (P < 0.05). No differences were detected for other blood parameters including glucose, total protein, albumin, cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, iron, magnesium, and glutathione peroxidase values. In conclusion, supplementation of CTM at the level of 1 g/bird/day to the drinking water can be recommended for improving growth performance, mineral absorption, and antioxidant status of ostriches fed diets containing the recommended levels of inorganic TM.

  14. Case studies for utilizing groundwater-source and low-enthalpy geothermal resources in Korea

    NASA Astrophysics Data System (ADS)

    Kim, K.-H.; Shin, J.; Lee, K.-K.; Lee, T. J.

    2012-04-01

    As one of the top 10 oil-consuming countries in the world, Korea recently has had a great interest in extending the ways to utilize renewable energy. In this regard, geothermal energy resource is attracting more concerns from both of the government and the research field. Korea has neither active volcanic sites nor areas with abnormally higher heat flow. In spite of these natural conditions, many efforts have been exerted to utilize geothermal energy. Here, we introduce two case studies of using groundwater-source geothermal energy with relatively low-enthalpy: One is a riverbank filtration facility, which has been using some of its riverbank filtrate water for the indoor air-conditioning. The other is the first EGS plant planning site, where a few fault-related artesian wells reaching 70C were discovered lately. Numerical simulations to predict the temperature evolution of the two sites, which is dominated by several hydrogeologic factors, were carried out and compared. Simulation of temperature profile of riverbank filtrate water using HydroGeoSphere shows that the primary factor in determining filtrate water temperature is the pumping rate. It also shows that maintaining the facility operation with present pumping rate for the next 30 years will not cause any significant change of water temperature. However, following the new plan of the facility to install additional 37 wells with 6 times higher pumping rate than the current rate might cause about 2C decrease in filtrate water temperature in 10 years after the extension. Simulation for the temperature evolution in a faulted geothermal reservoir in EGS planning site under the supposed injection-extraction operating conditions were carried out using TOUGH2. A MINC model including a hydraulic discontinuity, which reflected the analysis from several geophysical explorations, was generated. Temperature distribution calculated from the simulation shows a rise of relatively hot geothermal water along the fault plane

  15. Enthalpy Changes during Photosynthetic Water Oxidation Tracked by Time-Resolved Calorimetry Using a Photothermal Beam Deflection Technique☆☆☆

    PubMed Central

    Krivanek, Roland; Dau, Holger; Haumann, Michael

    2008-01-01

    The energetics of the individual reaction steps in the catalytic cycle of photosynthetic water oxidation at the Mn4Ca complex of photosystem II (PSII) are of prime interest. We studied the electron transfer reactions in oxygen-evolving PSII membrane particles from spinach by a photothermal beam deflection technique, allowing for time-resolved calorimetry in the micro- to millisecond domain. For an ideal quantum yield of 100%, the enthalpy change, ΔH, coupled to the formation of the radical pair YZ⋅+QA− (where YZ is Tyr-161 of the D1 subunit of PSII) is estimated as −820 ± 250 meV. For a lower quantum yield of 70%, the enthalpy change is estimated to be −400 ± 250 meV. The observed nonthermal signal possibly is due to a contraction of the PSII protein volume (apparent ΔV of about −13 Å3). For the first time, the enthalpy change of the O2-evolving transition of the S-state cycle was monitored directly. Surprisingly, the reaction is only slightly exergonic. A value of ΔH(S3 ⇒ S0) of −210 meV is estimated, but also an enthalpy change of zero is within the error range. A prominent nonthermal photothermal beam deflection signal (apparent ΔV of about +42 Å3) may reflect O2 and proton release from the manganese complex, but also reorganization of the protein matrix. PMID:17993488

  16. Fluorine follows water: Effect on electrical conductivity of silicate minerals by experimental constraints from phlogopite

    NASA Astrophysics Data System (ADS)

    Li, Yan; Jiang, Haotian; Yang, Xiaozhi

    2017-11-01

    Fluorine and hydroxyl groups are minor constituents of silicate minerals, and share a lot of similarities concerning their physical and chemical properties. Hydroxyl groups significantly enhance the electrical conductivity of many silicate minerals, and it is expected that fluorine would have a comparable effect. This, however, has never been documented quantitatively. Here we present experimental approaches on this issue, by investigating the electrical conductivity of phlogopite with a wide range of fluorine content (but with broadly similar contents for other major elements). Electrical conductivities of gem-quality single crystal phlogopites, with samples prepared along the same orientation (normal to the (0 0 1) plane), were determined at 1 GPa and 200-650 °C using an end-loaded piston cylinder apparatus and a Solartron-1260 Impedance/Gain Phase Analyzer over the frequency range of 106 to 0.1 Hz. The complex spectra usually show an arc in the high frequency range and a short tail in the low frequency range, which are caused by lattice conduction and electrode effects, respectively. The electrical conductivity increases with increasing fluorine content, and the main charge carriers are fluorine. The activation enthalpies are ∼180 to 200 kJ/mol, nearly independent of fluorine content. The conductivity is linearly proportional to the content of fluorine, with an exponent factor of ∼1. The results demonstrate that conduction by fluorine leads to very high electrical conductivity at high temperatures. The influence of fluorine on electrical conductivity may be compared to that of hydrogen in nominally anhydrous minerals. This, along with the close association of fluorine and hydroxyl groups in silicate minerals and their similar crystal-chemical behaviors, suggests a more general role of fluorine in enhancing the electrical conductivity of many silicate minerals. Fluorine-rich assemblages, e.g., phlogopite and amphibole, could be locally enriched in the upper

  17. Climate-change-driven deterioration of water quality in a mineralized watershed.

    PubMed

    Todd, Andrew S; Manning, Andrew H; Verplanck, Philip L; Crouch, Caitlin; McKnight, Diane M; Dunham, Ryan

    2012-09-04

    A unique 30-year streamwater chemistry data set from a mineralized alpine watershed with naturally acidic, metal-rich water displays dissolved concentrations of Zn and other metals of ecological concern increasing by 100-400% (400-2000 μg/L) during low-flow months, when metal concentrations are highest. SO(4) and other major ions show similar increases. A lack of natural or anthropogenic land disturbances in the watershed during the study period suggests that climate change is the underlying cause. Local mean annual and mean summer air temperatures have increased at a rate of 0.2-1.2 °C/decade since the 1980s. Other climatic and hydrologic indices, including stream discharge during low-flow months, do not display statistically significant trends. Consideration of potential specific causal mechanisms driven by rising temperatures suggests that melting of permafrost and falling water tables (from decreased recharge) are probable explanations for the increasing concentrations. The prospect of future widespread increases in dissolved solutes from mineralized watersheds is concerning given likely negative impacts on downstream ecosystems and water resources, and complications created for the establishment of attainable remediation objectives at mine sites.

  18. Climate-change-driven deterioration of water quality in a mineralized watershed

    USGS Publications Warehouse

    Todd, Andrew; Manning, Andrew H.; Verplanck, Philip L.; Crouch, Caitlin; McKnight, Diane M.; Dunham, Ryan

    2012-01-01

    A unique 30-year streamwater chemistry data set from a mineralized alpine watershed with naturally acidic, metal-rich water displays dissolved concentrations of Zn and other metals of ecological concern increasing by 100–400% (400–2000 μg/L) during low-flow months, when metal concentrations are highest. SO4 and other major ions show similar increases. A lack of natural or anthropogenic land disturbances in the watershed during the study period suggests that climate change is the underlying cause. Local mean annual and mean summer air temperatures have increased at a rate of 0.2–1.2 °C/decade since the 1980s. Other climatic and hydrologic indices, including stream discharge during low-flow months, do not display statistically significant trends. Consideration of potential specific causal mechanisms driven by rising temperatures suggests that melting of permafrost and falling water tables (from decreased recharge) are probable explanations for the increasing concentrations. The prospect of future widespread increases in dissolved solutes from mineralized watersheds is concerning given likely negative impacts on downstream ecosystems and water resources, and complications created for the establishment of attainable remediation objectives at mine sites.

  19. Sequential water molecule binding enthalpies for aqueous nanodrops containing a mono-, di- or trivalent ion and between 20 and 500 water molecules† †Electronic supplementary information (ESI) available: Detailed description of the experimental and computational modeling methods. Isolation, BIRD and UVPD sequence for [Ru(NH3)6]3+·(H2O)169–171, nanoESI spectra for 2+ and 3+ ions. Detailed description of the isotope distribution simulation program. Comparison between experimental and simulated 1+, 2+ and 3+ ion isotope distributions. Wavelength dependence of the deduced sequential binding enthalpies. Comparison of experimental UVPD binding enthalpies to the liquid drop model at different temperatures. Complete list of binding enthalpies and average number of water molecules lost upon UVPD. See DOI: 10.1039/c6sc04957e Click here for additional data file.

    PubMed Central

    Heiles, Sven; Cooper, Richard J.; DiTucci, Matthew J.

    2017-01-01

    Sequential water molecule binding enthalpies, ΔH n,n–1, are important for a detailed understanding of competitive interactions between ions, water and solute molecules, and how these interactions affect physical properties of ion-containing nanodrops that are important in aerosol chemistry. Water molecule binding enthalpies have been measured for small clusters of many different ions, but these values for ion-containing nanodrops containing more than 20 water molecules are scarce. Here, ΔH n,n–1 values are deduced from high-precision ultraviolet photodissociation (UVPD) measurements as a function of ion identity, charge state and cluster size between 20–500 water molecules and for ions with +1, +2 and +3 charges. The ΔH n,n–1 values are obtained from the number of water molecules lost upon photoexcitation at a known wavelength, and modeling of the release of energy into the translational, rotational and vibrational motions of the products. The ΔH n,n–1 values range from 36.82 to 50.21 kJ mol–1. For clusters containing more than ∼250 water molecules, the binding enthalpies are between the bulk heat of vaporization (44.8 kJ mol–1) and the sublimation enthalpy of bulk ice (51.0 kJ mol–1). These values depend on ion charge state for clusters with fewer than 150 water molecules, but there is a negligible dependence at larger size. There is a minimum in the ΔH n,n–1 values that depends on the cluster size and ion charge state, which can be attributed to the competing effects of ion solvation and surface energy. The experimental ΔH n,n–1 values can be fit to the Thomson liquid drop model (TLDM) using bulk ice parameters. By optimizing the surface tension and temperature change of the logarithmic partial pressure for the TLDM, the experimental sequential water molecule binding enthalpies can be fit with an accuracy of ±3.3 kJ mol–1 over the entire range of cluster sizes. PMID:28451364

  20. Natural mineral waters, curative-medical waters and their protection

    NASA Astrophysics Data System (ADS)

    Fricke, M.

    1993-10-01

    In Europe different types of water are marketed, each strictly defined by EC Directive 80/777 (Natural Mineral Water, Spring and Table Water) or 80/778 (Drinking Water). In Germany, an additional type of water is common in the market: curative/medical water. Product quality and safety, registration as medicine, and pharmaceutical control are defined by the German Federal Medicine Act. A medical water is treated as any other medicine and may be sold only in pharmacies. The use of any water in Germany is controlled and strictly regulated by the Federal Water Act (Fricke 1981). The following requirements are set by the act: (1) No water use without a permit, which is limited in time and quantity. (2) No single or juristic person may own water. (3) Water resources of public interest and their recharge areas are to be protected by the definition of water protection zones. (Natural mineral water is not of public interest and therefore is not required to be protected by the definition of water protection zones, although it represents a market value of more than US2 billion. Medical water is of public interest). The definition of water protection zones impacts private property rights and has to be handled carefully. In order to protect water resources, sometimes the economic basis of a traditional industrial and/or agricultural infrastructure is destroyed. The concerns and needs all citizens, including industry, must be considered in analyzing the adequacy of water protection zones.

  1. Investigation of uranium binding forms in selected German mineral waters.

    PubMed

    Osman, Alfatih A A; Geipel, Gerhard; Bernhard, Gert; Worch, Eckhard

    2013-12-01

    Cryogenic time-resolved laser-induced fluorescence spectroscopy was successfully used to identify uranium binding forms in selected German mineral waters of extremely low uranium concentrations (<2.0 μg/L). The measurements were performed at a low temperature of 153 K. The spectroscopic data showed a prevalence of aquatic species Ca2UO2(CO3)3 in all investigated waters, while other uranyl-carbonate complexes, viz, UO2CO3(aq) and UO2(CO3)2 (2-), only existed as minor species. The pH value, alkalinity (CO3 (2-)), and the main water inorganic constituents, specifically the Ca(2+) concentration, showed a clear influence on uranium speciation. Speciation modeling was performed using the most recent thermodynamic data for aqueous complexes of uranium. The modeling results for the main uranium binding form in the investigated waters indicated a good agreement with the spectroscopy measurements.

  2. Natural mineral bottled waters available on the Polish market as a source of minerals for the consumers. Part 1. Calcium and magnesium.

    PubMed

    Gątarska, Anna; Tońska, Elżbieta; Ciborska, Joanna

    2016-01-01

    Natural mineral waters may be an essential source of calcium, magnesium and other minerals. In bottled waters, minerals occur in an ionized form which is very well digestible. However, the concentration of minerals in underground waters (which constitute the material for the production of bottled waters) varies. In view of the above, the type of water consumed is essential. The aim of the study was to estimate the calcium and magnesium contents in products available on the market and to evaluate calcium and magnesium consumption with natural mineral water by different consumer groups with an assumed volume of the consumed product. These represented forty different brands of natural mineral available waters on Polish market. These waters were produced in Poland or other European countries. Among the studied products, about 30% of the waters were imported from Lithuania, Latvia, Czech Republic, France, Italy and Germany. The content of calcium and magnesium in mineral waters was determined using flame atomic absorption spectrometry in an acetylene-air flame. Further determinations were carried out using atomic absorption spectrometer--ICE 3000 SERIES-THERMO-England, equipped with a GLITE data station, background correction (a deuterium lamp) as well as other cathode lamps. Over half of the analysed natural mineral waters were medium-mineralized. The natural mineral waters available on the market can be characterized by a varied content of calcium and magnesium and a high degree of product mineralization does not guarantee significant amounts of these components. Among the natural mineral waters available on the market, only a few feature the optimum calcium-magnesium proportion (2:1). Considering the mineralization degree of the studied products, it can be stated that the largest percentage of products with significant calcium and magnesium contents can be found in the high-mineralized water group. For some natural mineral waters, the consumption of 1 litre daily may

  3. Trace analysis of parabens preservatives in drinking water treatment sludge, treated, and mineral water samples.

    PubMed

    Marta-Sanchez, Ana Victoria; Caldas, Sergiane Souza; Schneider, Antunielle; Cardoso, Sónia Maria Vaz Sanches; Primel, Ednei Gilberto

    2018-05-01

    Parabens have been widely used as antimicrobial agents, mainly in food products, pharmaceuticals, and cosmetics. Although they are known as safe preservatives, they also cause some harm to human health, which has been discussed lately. Therefore, the aim of this study was to evaluate the occurrence of nine parabens (including isomers) in mineral and drinking waters, besides in drinking water treatment sludge (DWTS) samples with determination by liquid chromatography tandem mass spectrometry (LC-MS/MS). Both methods solid phase extraction (SPE) and QuEChERS were validated. Calibration curves showed a correlation coefficient of 0.99 for all compounds. LOQ values ranged from 0.04 to 4 μg L -1 in aqueous matrices and from 5 to 500 ng g -1 in DWTS. Recoveries between 70 and 115% were reached with RSD below 20% for all compounds in SPE whereas recoveries between 62 and 119% were found with RSD below 20% for almost all compounds in QuEChERS. Matrix effect had low values (< 20%); it was only above 20% for methylparaben in the SPE and for pentylparaben in the QuEChERS. Using a quick and simple extraction procedures with SPE, QuEChERS, and LC-MS/MS analyses, these methods proved to be selective and sensitive. They were successfully applied to real samples (treated water, mineral water, and sludge), and methylparaben was detected at concentration levels below 0.242 μg L -1 in mineral and treated water samples and 10 ng g -1 in DWTS samples.

  4. Microcoulometric measurement of water in minerals

    USGS Publications Warehouse

    Cremer, M.; Elsheimer, H.N.; Escher, E.E.

    1972-01-01

    A DuPont Moisture Analyzer is used in a microcoulometric method for determining water in minerals. Certain modifications, which include the heating of the sample outside the instrument, protect the system from acid gases and insure the conversion of all hydrogen to water vapor. Moisture analyzer data are compared to concurrent data obtained by a modified Penfield method. In general, there is a positive bias of from 0.1 to 0.2% in the moisture analyzer results and a similarity of bias in minerals of the same kind. Inhomogeneity, sample size, and moisture pick-up are invoked to explain deviations. The method is particularly applicable to small samples. ?? 1972.

  5. Heat capacty, relative enthalpy, and calorimetric entropy of silicate minerals: an empirical method of prediction.

    USGS Publications Warehouse

    Robinson, G.R.; Haas, J.L.

    1983-01-01

    Through the evaluation of experimental calorimetric data and estimates of the molar isobaric heat capacities, relative enthalpies and entropies of constituent oxides, a procedure for predicting the thermodynamic properties of silicates is developed. Estimates of the accuracy and precision of the technique and examples of its application are also presented. -J.A.Z.

  6. Measuring the enthalpies of interaction between glycine, L-cysteine, glycylglycine, and sodium dodecyl sulfate in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Badelin, V. G.; Mezhevoi, I. N.; Tyunina, E. Yu.

    2017-03-01

    Calorimetric measurements of enthalpies of solution Δsol H m for glycine, L-cysteine, and glycylglycine in aqueous solutions of sodium dodecyl sulfate (SDS) with concentrations of up to 0.05 mol kg-1 are made. Standard enthalpy of solution Δsol H 0 and enthalpy of transfer Δtr H 0 of the dipeptide from water into mixed solvent are calculated. The calculated enthalpy coefficients of paired interactions of amino acids and dipeptide with SDS prove to be positive. Hydrophobic interactions between the biomolecules and SDS are found to have a major impact on the enthalpies of interaction in the three-component systems under study, within the indicated range of concentrations.

  7. [INDICES OF THE OXIDATIVE STATUS IN CHRONIC ADMINISTRATION OF COLLOID CARBONATE CALCIUM PRAPARATION WITH FAUCET AND LOW-MINERALIZED DRINKING WATER IN RATS].

    PubMed

    Khripach, L V; Mikhaylova, R I; Koganova, Z I; Knyazeva, T D; Alekseeva, A V; Savostikova, O N; Ryzhova, I N; Kruglova, E V; Revzova, T L

    2015-01-01

    There are discussed the changes of an array of indices of the oxidative status in chronic administration of colloidal calcium carbonate preparation with faucet and low-mineralized drinking water to rats. Slight differences between significant effects of administration of 3 and 30 mg/L of preparation permit to suggest that the process of its incoming delivery into organism of rats has a bottleneck in the nature of total capacity of macrophages of intestinal lymphoid tissue to absorption of particles.

  8. [The ultrastructure of Leydig cells under the influence of drinking mineral water and electromagnetic radiation under the stress conditions in the rats].

    PubMed

    Geniatulina, M S; Korolev, Yu N; Nikulina, L A

    The objective of the present study was elucidate the peculiar features of low-intensity electromagnetic radiation (LI EMR) and mineral water (MW) on the ultrastructure of rat Leydig cells under conditions of immobilization stress. The experiments were carried out on outbred male rats with the use of electron microscopy. It has been demonstrated that the prophylactic consumption of drinking sulfate-containing mineral water and the application low-intensity electromagnetic radiation (with the flow power density of 1 mcW/cm2 and frequency around 1,000 Hz) or the combination of these two modalities under conditions of immobilization stress reduced the degree of ultrastructural derangement in the rat Leydig cells and stimulated the development of regenerative processes. In the cases of the single-factor impact, drinking mineral water exerted more pronounced action than low-intensity electromagnetic radiation on mitochondrial regeneration. In case of the simultaneous application of the two factors their protective action on the Leydig cells was much more conspicuous than that of either of them applied alone. It is concluded that drinking sulfate-containing mineral water in combination with the application of low-intensity electromagnetic radiation enhances resistance of the rat Leydig cells to stress.

  9. Monitoring the impact of urban effluents on mineral contents of water and sediments of four sites of the river Ravi, Lahore.

    PubMed

    Shakir, Hafiz Abdullah; Qazi, Javed Iqbal; Chaudhry, Abdul Shakoor

    2013-12-01

    We assessed the impact of urban effluents on the concentrations of selected minerals (Cd, Cr, Cu, Fe, Pb, Zn, Mn, Ni, and Hg) in river Ravi before and after its passage through Lahore city. Water and sediment samples were collected from three lowly to highly polluted downstream sites (Shahdera (B), Sunder (C), and Balloki (D)) alongside the least polluted upstream site (Siphon (A)) during high and low river flow seasons. All the mineral concentrations increased up to site C but stabilized at site D, showing some recovery as compared to the third sampling site. The trend of mean mineral concentration was significantly higher during the low than the high flow season at all the sites. The mean Hg concentrations approached 0.14 and 0.12 mg/l at site A which increased (%) up to 107 and 25% at site B, 1,700 and 1,317% at site C, and 1,185 and 1,177% at site D during low and high river flows, respectively. All mineral concentrations were much higher in the sediment than the water samples. Mean Cd (917%), Cr (461%), Cu (300%), Fe (254%), Pb (179%), Zn (170%), Mn (723%), Ni (853%), and Hg (1,699%) concentrations were higher in riverbed sediments sampled from site C in comparison with the sample collected at site A during low flow season. The domestic and industrial discharges from Lahore city have created undesirable water qualities during the low river flow season. As majority of the mineral levels in the river Ravi were higher than the permissible and safe levels, this is of immediate concern for riverine fish consumers and the users of water for recreation and even irrigation. The use of these waters may pose health risks, and therefore, urgent intervention strategies are needed to minimize river water pollution and its impact on fish-consuming communities of this study area and beyond.

  10. Hydrogeochemical processes governing the origin, transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters

    USGS Publications Warehouse

    Nordstrom, D. Kirk

    2011-01-01

    Mobility of potential or actual contaminants from mining and mineral processing activities depends on (1) occurrence: is the mineral source of the contaminant actually present? (2) abundance: is the mineral present in sufficient quantity to make a difference? (3) reactivity: what are the energetics, rates, and mechanisms of sorption and mineral dissolution and precipitation relative to the flow rate of the water? and (4) hydrology: what are the main flow paths for contaminated water? Estimates of relative proportions of minerals dissolved and precipitated can be made with mass-balance calculations if minerals and water compositions along a flow path are known. Combined with discharge, these mass-balance estimates quantify the actual weathering rate of pyrite mineralization in the environment and compare reasonably well with laboratory rates of pyrite oxidation except when large quantities of soluble salts and evaporated mine waters have accumulated underground. Quantitative mineralogy with trace-element compositions can substantially improve the identification of source minerals for specific trace elements through mass balances. Post-dissolution sorption and precipitation (attenuation) reactions depend on the chemical behavior of each element, solution composition and pH, aqueous speciation, temperature, and contact-time with mineral surfaces. For example, little metal attenuation occurs in waters of low pH (2, and redox-sensitive oxyanions (As, Sb, Se, Mo, Cr, V). Once dissolved, metal and metalloid concentrations are strongly affected by redox conditions and pH. Iron is the most reactive because it is rapidly oxidized by bacteria and archaea and Fe(III) hydrolyzes and precipitates at low pH (1–3) which is related directly to its first hydrolysis constant, pK1 = 2.2. Several insoluble sulfate minerals precipitate at low pH including anglesite, barite, jarosite, alunite and basaluminite. Aluminum hydrolyzes near pH 5 (pK1 = 5.0) and provides buffering and removal

  11. Use of ferric-impregnated volcanic ash for arsenate (V) adsorption from contaminated water with various mineralization degrees.

    PubMed

    Chen, Rongzhi; Zhang, Zhenya; Yang, Yingnan; Lei, Zhongfang; Chen, Nan; Guo, Xu; Zhao, Chao; Sugiura, Norio

    2011-01-15

    Ferric-impregnated volcanic ash (FVA) which consisted mainly of different forms of iron and aluminum oxide minerals was developed for arsenate (V) removal from an aqueous medium. The adsorption experiments were conducted in both DI water samples and actual water (Lake Kasumigaura, Japan) to investigate the effects of solution mineralization degree on the As(V) removal. Kinetic and equilibrium studies conducted in actual water revealed that the mineralization of water greatly elevated the As(V) adsorption on FVA. The experiment performed in DI water indicated that the existence of multivalence metallic cations significantly enhanced the As(V) adsorption ability, whereas competing anions such as fluoride and phosphate greatly decreased the As(V) adsorption. It is suggested that FVA is a cost-effective adsorbent for As(V) removal in low-level phosphate and fluoride solution. It was important to conduct the batch experiment using the actual water to investigate the arsenic removal on adsorbents. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. The effect of mineral-based alkaline water on hydration status and the metabolic response to short-term anaerobic exercise

    PubMed Central

    Chycki, Jakub; Zając, Tomasz; Kurylas, Anna

    2017-01-01

    Previously it was demonstrated that mineralization and alkalization properties of mineral water are important factors influencing acid-base balance and hydration in athletes. The purpose of this study was to investigate the effects of drinking different types of water on urine pH, specific urine gravity, and post-exercise lactate utilization in response to strenuous exercise. Thirty-six male soccer players were divided into three intervention groups, consuming around 4.0 l/day of different types of water for 7 days: HM (n=12; highly mineralized water), LM (n=12; low mineralized water), and CON (n=12; table water). The athletes performed an exercise protocol on two occasions (before and after intervention). The exercise protocol consisted of 5 bouts of intensive 60-s (120% VO2max) cycling separated by 60 s of passive rest. Body composition, urinalysis and lactate concentration were evaluated – before (t0), immediately after (t1), 5’ (t2), and 30’ (t3) after exercise. Total body water and its active transport (TBW – total body water / ICW – intracellular water / ECW – extracellular water) showed no significant differences in all groups, at both occasions. In the post-hydration state we found a significant decrease of specific urine gravity in HM (1021±4.2 vs 1015±3.8 g/L) and LM (1022±3.1 vs 1008±4.2 g/L). We also found a significant increase of pH and lactate utilization rate in LM. In conclusion, the athletes hydrated with alkaline, low mineralized water demonstrated favourable changes in hydration status in response to high-intensity interval exercise with a significant decrease of specific urine gravity, increased urine pH and more efficient utilization of lactate after supramaximal exercise. PMID:29158619

  13. The effect of mineral-based alkaline water on hydration status and the metabolic response to short-term anaerobic exercise.

    PubMed

    Chycki, Jakub; Zając, Tomasz; Maszczyk, Adam; Kurylas, Anna

    2017-09-01

    Previously it was demonstrated that mineralization and alkalization properties of mineral water are important factors influencing acid-base balance and hydration in athletes. The purpose of this study was to investigate the effects of drinking different types of water on urine pH, specific urine gravity, and post-exercise lactate utilization in response to strenuous exercise. Thirty-six male soccer players were divided into three intervention groups, consuming around 4.0 l/day of different types of water for 7 days: HM (n=12; highly mineralized water), LM (n=12; low mineralized water), and CON (n=12; table water). The athletes performed an exercise protocol on two occasions (before and after intervention). The exercise protocol consisted of 5 bouts of intensive 60-s (120% VO 2max ) cycling separated by 60 s of passive rest. Body composition, urinalysis and lactate concentration were evaluated - before (t0), immediately after (t1), 5' (t2), and 30' (t3) after exercise. Total body water and its active transport (TBW - total body water / ICW - intracellular water / ECW - extracellular water) showed no significant differences in all groups, at both occasions. In the post-hydration state we found a significant decrease of specific urine gravity in HM (1021±4.2 vs 1015±3.8 g/L) and LM (1022±3.1 vs 1008±4.2 g/L). We also found a significant increase of pH and lactate utilization rate in LM. In conclusion, the athletes hydrated with alkaline, low mineralized water demonstrated favourable changes in hydration status in response to high-intensity interval exercise with a significant decrease of specific urine gravity, increased urine pH and more efficient utilization of lactate after supramaximal exercise.

  14. Water-bearing minerals on mars: source of observed mid-latitude water?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bish, D. L.; Carey, J. W.; Fialips, C. I.

    2003-01-01

    The Odyssey spacecraft documented the existence of heterogeneously distributed hydrogen at martian mid-latitudes, suggesting that large areas of the near-equatorial highlands contain near-surface deposits of 'chemically and/or physically bound H20 and/or OH' in amounts up to 3 .8% equivalent H20. Shallow occurrences of water ice are not stable near the martian equator, making the hydrogen deposits at these latitudes somewhat enigmatic. Clay minerals and zeolites have both been proposed as possible water-bearing constituents on Mars, and both are common terrestrial alteration products of hydrovolcanic basaltic ashes and palagonitic material comparable to those that may be widespread on Mars. Smectites withinmore » martian meteorites, attributed to hydrous alteration on Mars rather than on Earth, provide direct evidence of clay minerals from Mars. In addition, new thermal emission spectrometer (TES) data provide good evidence for unspecified zeolites in martian surface dust [6] . The nature of the hydrogen-containing material observed in the equatorial martian regolith is of particular importance to the question of whether hydrous minerals have formed in the past on Mars. Also, whether these minerals exist in a hydrated (i .e., containing H2O molecules in their structures) or dehydrated state is a crucial question . The existence of hydrous minerals is also important in connection with their possible role in affecting the diurnal variation of the martian atmosphere, in their potential role in unraveling the paleohydrology and paleobiology of Mars, and in their possible use as a water resource to support exploration of the martian mid-latitudes.« less

  15. Trace metal contamination of mineral spring water in an historical mining area in regional Victoria, Australia

    NASA Astrophysics Data System (ADS)

    Martin, Rachael; Dowling, Kim

    2013-11-01

    Significant global consumption of spring and mineral water is fuelled by perceived therapeutic and medicinal qualities, cultural habits and taste. The Central Victorian Mineral Springs Region, Australia comprises approximately 100 naturally effervescent, cold, high CO2 content springs with distinctive tastes linked to a specific spring or pump. The area has a rich settlement history. It was first settled by miners in the 1840s closely followed by the first commercial operations of a health resort 1895. The landscape is clearly affected by gold mining with geographically proximal mine waste, mullock heaps or tailings. Repeated mineral springs sampling since 1985 has revealed elevated arsenic concentrations. In 1985 an arsenic concentration five times the current Australian Drinking Water Guideline was recorded at a popular tourist spring site. Recent sampling and analyses have confirmed elevated levels of heavy metals/metalloids, with higher concentrations occurring during periods of low rainfall. Despite the elevated levels, mineral water source points remain accessible to the public with some springs actively promoting the therapeutic benefits of the waters. In light of our analysis, the risk to consumers (some of whom are likely to be negatively health-affected or health-compromised) needs to be considered with a view to appropriate and verified analyses made available to the public.

  16. Enthalpy effects on hypervelocity boundary layers

    NASA Astrophysics Data System (ADS)

    Adam, Philippe H.

    Shots with air and carbon dioxide were carried out in the T5 shock tunnel at GALCIT to study enthalpy effects on hypervelocity boundary layers. The model tested was a 1-meter long, 5-deg half-angle cone. It was instrumented with 51 chromel-constantan coaxial thermocouples and the surface heat transfer rate was computed to deduce the state of the boundary layer. Transitional boundary layers obtained confirm the stabilizing effect of enthalpy. As the reservoir enthalpy is increased, the transition Reynolds number evaluated at the reference conditions increases. This stabilizing effect is more rapid in gases with lower dissociation energy and it seems to level off when no further dissociation can be achieved. Normalizing the reservoir enthalpy with the edge enthalpy appears to collapse the data for all gases onto a single curve. A similar collapse is obtained when normalizing both the transition location and the reservoir enthalpy with the maximum temperature conditions obtained with BLIMPK, a nonequilibrium boundary layer code. The observation that reference conditions are more appropriate to normalize high enthalpy transition data was taken a step further by comparing the tunnel data with results from a reentry experiment. When the edge conditions are used, the tunnel and flight data are around an order of magnitude apart. This is commonly attributed to high disturbance levels in tunnels that cause the boundary layer to transition early. However, when the reference conditions are used instead, the tunnel and flight data come within striking distance of one another although the trends with enthalpy are reversed. This difference could be due to the cone bending and nose blunting. Experimental laminar heat transfer levels were compared to numerical results obtained with BLIMPK. Results for air indicate that the reactions are probably in nonequilibrium and that the wall is catalytic. The catalycity is seen to yield higher surface heat transfer rates than the

  17. The mineral content of tap water in United States households

    USDA-ARS?s Scientific Manuscript database

    The composition of tap water contributes to dietary intake of minerals. The USDA’s Nutrient Data Laboratory (NDL) conducted a study of the mineral content of residential tap water, to generate current data for the USDA National Nutrient Database. Sodium, potassium, calcium, magnesium, iron, copper...

  18. Population data on calcium in drinking water and hip fracture: An association may depend on other minerals in water. A NOREPOS study.

    PubMed

    Dahl, Cecilie; Søgaard, Anne Johanne; Tell, Grethe S; Forsén, Lisa; Flaten, Trond Peder; Hongve, Dag; Omsland, Tone Kristin; Holvik, Kristin; Meyer, Haakon E; Aamodt, Geir

    2015-12-01

    The Norwegian population has among the highest hip fracture rates in the world. The incidence varies geographically, also within Norway. Calcium in drinking water has been found to be beneficially associated with bone health in some studies, but not in all. In most previous studies, other minerals in water have not been taken into account. Trace minerals, for which drinking water can be an important source and even fulfill the daily nutritional requirement, could act as effect-modifiers in the association between calcium and hip fracture risk. The aim of the present study was to investigate the association between calcium in drinking water and hip fracture, and whether other water minerals modified this association. A survey of trace metals in 429 waterworks, supplying 64% of the population in Norway, was linked geographically to the home addresses of patients with incident hip fractures (1994-2000). Drinking water mineral concentrations were divided into "low" (below and equal waterworks average) and "high" (above waterworks average). Poisson regression models were fitted, and all incidence rate ratios (IRRs) were adjusted for age, geographic region, urbanization degree, type of water source, and pH of the water. Effect modifications were examined by stratification, and interactions between calcium and magnesium, copper, zinc, iron and manganese were tested both on the multiplicative and the additive scale. Analyses were stratified on gender. Among those supplied from the 429 waterworks (2,110,916 person-years in men and 2,397,217 person-years in women), 5433 men and 13,493 women aged 50-85 years suffered a hip fracture during 1994-2000. Compared to low calcium in drinking water, a high level was associated with a 15% lower hip fracture risk in men (IRR=0.85, 95% CI: 0.78, 0.91) but no significant difference was found in women (IRR=0.98, 95%CI: 0.93-1.02). There was interaction between calcium and copper on hip fracture risk in men (p=0.051); the association

  19. Prevention and Therapy of Type 2 Diabetes—What Is the Potential of Daily Water Intake and Its Mineral Nutrients?

    PubMed Central

    Naumann, Johannes; Biehler, Diana; Lüty, Tania

    2017-01-01

    We aim to present an overview of the possible influence of drinking water in general and mineral water in particular in improving glycemic parameters in persons with or without type 2 diabetes. We performed a literature search that produced 15 randomized controlled trials (RCTs) on this topic with mainly small sample sizes. We also discuss relevant observational and animal studies as well as the effects of important supplements in mineral water such as hydrogencarbonate and magnesium. There is low evidence for the positive effects of water or mineral water in improving glycemic parameters in diabetic and non-diabetic persons, and the results are heterogenous, making it difficult to reach an unequivocal conclusion. Meta-analyses of prospective cohort studies and other observational studies, studies with animal models and interventional studies using hydrogencarbonate and magnesium supplements suggest a probable positive effect of drinking water and mineral water in particular on glycemic parameters, supporting the positive results found in some of the RCTs, especially those substituting diet beverages or caloric beverages with water, or those using bicarbonate and magnesium-rich water. Regarding the high prevalence, the associated suffering and the resulting health expenditures of type 2 diabetes, it is imperative to conduct larger and more rigorous trials to answer the question whether drinking water or mineral water can improve glycemic parameters in diabetic and non-diabetic persons. PMID:28829398

  20. Prevention and Therapy of Type 2 Diabetes-What Is the Potential of Daily Water Intake and Its Mineral Nutrients?

    PubMed

    Naumann, Johannes; Biehler, Diana; Lüty, Tania; Sadaghiani, Catharina

    2017-08-22

    We aim to present an overview of the possible influence of drinking water in general and mineral water in particular in improving glycemic parameters in persons with or without type 2 diabetes. We performed a literature search that produced 15 randomized controlled trials (RCTs) on this topic with mainly small sample sizes. We also discuss relevant observational and animal studies as well as the effects of important supplements in mineral water such as hydrogencarbonate and magnesium. There is low evidence for the positive effects of water or mineral water in improving glycemic parameters in diabetic and non-diabetic persons, and the results are heterogenous, making it difficult to reach an unequivocal conclusion. Meta-analyses of prospective cohort studies and other observational studies, studies with animal models and interventional studies using hydrogencarbonate and magnesium supplements suggest a probable positive effect of drinking water and mineral water in particular on glycemic parameters, supporting the positive results found in some of the RCTs, especially those substituting diet beverages or caloric beverages with water, or those using bicarbonate and magnesium-rich water. Regarding the high prevalence, the associated suffering and the resulting health expenditures of type 2 diabetes, it is imperative to conduct larger and more rigorous trials to answer the question whether drinking water or mineral water can improve glycemic parameters in diabetic and non-diabetic persons.

  1. Correction methods of medicinal properties of mineral waters in Pyatigorsk resort

    NASA Astrophysics Data System (ADS)

    Reps, Valentina; Potapov, Evgeniy; Abramtsova, Anna; Kotova, Margarita

    2016-04-01

    Mineral Water (MW) of Pyatigorsk deposit (PD) is united in five genetic groups (operational stocks of 2809,8 m3/day): carbonic and hydrosulphuric, carbonic, carbonic chloride-hydrocarbonate sodium (salt and alkaline), radonic low carbonate, nitrogen-carbonic terms. A variety of MW types is explained by peculiarities of geological structure and hydrogeological conditions of PD. Here on the sites of the development of deep semi-ring splits there are overflows and a mixture of various complexes. Unloading of deep water strikes happens not only on the earth surface in the form of springs but also at the depth in its edging crumbling rocks of Palaeocene and quarternary deposits. As a result of mixture processes of water and its subsequent metamorphization, various types of mineral water of this deposit are formed. Pyatigorsk resort is in a special protected ecologo-resort region which mode allows to keep stability of structure and ecological purity of MW. Nevertheless, MW variability, compositional differences and MW mineralization determining the level of its biological effect demand studying of action mechanisms of both natural MW, and possibility of its modification for range expansion of rehabilitation action. There have been examined biological effects of the course drinking reception In experiment on 80 rats males of the Wistar line biological effects of the course drinking reception of two MW types: "Krasnoarmeyskaya new" (MW1) of sulphate-hydrocarbonate-chloride calcium-sodium structure with the raised contents of iron (3-5 mg/dm3), mineralization of 5,0-5,2 g/dm3, CO2 of 1,3-2,2 g/dm3, daily flow of 10-86 m3/day, temperature from 14 to 370C on the mouth of the well and spring №2 (MW2) low sulphate, low carbonate sulphate-hydrocarbonate-chloride calcium-sodium, mineralization of 5,0 g/l, CO2 of 0,7 g/dm3, H2 of S 0,01 g/dm3. There has been shown an ability of the drinking course MW1 to influence on endocrine and metabolic continium - cortisol level increased

  2. Mineral concentrations in diets, water, and milk and their value in estimating on-farm excretion of manure minerals in lactating dairy cows.

    PubMed

    Castillo, A R; St-Pierre, N R; Silva del Rio, N; Weiss, W P

    2013-05-01

    Thirty-nine commercial dairies in Merced County, California were enrolled in the present study to (1) compare lactating cow mineral intakes (via drinking water and total mixed ration) to the National Research Council (NRC) requirements, (2) evaluate the association between dietary concentrations of minerals with and without drinking water and adjusted for mineral concentrations in milk, and (3) compare 4 different methods to estimate excretion of minerals using either assays or estimations of milk mineral outputs and total daily mineral intake per cow with or without minerals coming from drinking water. Dairies were selected to represent a range of herd milk yields and a range of water mineral contents. Samples of total mixed ration, drinking water, and bulk tank milk were taken on 2 different days, 3 to 7d apart in each farm. Across-farm medians and percentile distributions were used to analyze results. The herd median milk yield interquartile ranged (10th to 90th percentile) from less than 25 to more than 39 kg/d and the concentration of total solids in water interquartile ranged from less than 200 to more than 1,490 mg/L. Including drinking water minerals in the diets increased dietary concentrations by <4% for all minerals except for Na and Cl, which increased by 9.3 and 6.5%, respectively. Concentrations of P and K in milk were essentially the same as the NRC value to estimate lactation requirements. However, NRC milk values of Ca, Cl, and Zn were 10 to 20% greater than dairy farm values; and Na, Cu, Fe, and Mn were no less than 36% below NRC values. Estimated excretion of minerals via manure varied substantially across farms. Farms in the 10th percentile did have 2 to 3 times less estimated mineral excretions than those in the 90th percentile (depending on the mineral). Although including water minerals increased excretion of most minerals, the actual median effect of Ca, Mg, S, Cu, Fe, and Mn was less than 5%, and about 8% for Na and Cl. Replacing assayed

  3. The Springhill Formation (Jurassic-Cretaceous) as a potential low enthalpy geothermal reservoir in the Cerro Sombrero area, Magallanes Basin, Chile.

    NASA Astrophysics Data System (ADS)

    Lagarrigue, S. C.; Elgueta, S.; Arancibia, G.; Morata, D.; Sanchez, J.; Rojas, L.

    2017-12-01

    Low enthalpy geothermal energy technologies are being developed around the world as part of policies to replace the use of conventional sources of energy by renewable ones. The reuse of abandoned oil and gas wells in sedimentary basins, whose reservoirs are saturated with water at temperatures above 120°C, is of increasing interest due to the low initial cost.In Chile, interest in applying this technology is focused on the Magallanes Basin (Austral Basin in Argentina) in the extreme south of the country, where important hydrocarbon deposits have been exploited for more than six decades with more than 3,500 wells drilled to depths of over 4,000m. Hydrocarbons have been extracted mainly from the Upper Jurassic to lowermost Cretaceous Springhill Formation, which includes sandstone lithofacies with porosities of 12% to 19% and permeability of 10mD and 1100mD. This formation has been drilled mainly at depths of 1500m to 3000m, the estimated geothermal gradient in the zone is 4.9 °C/100m with well bottom temperature measurements oscillating between 60° and 170°C, sufficient for district heating, and even, electricity generation by means of ORC technologies.To understand in detail the behavior and distribution of the different lithofacies of the Springhill Formation in the Sombrero Oil and Gas Field, sedimentological and geological 3D models have been generated from existing well logs and seismic data. To comprehend the quality of the reservoirs on the other hand, many petrophysical studies of drill core samples representative of the different lithofacies, complemented by electric well log interpretations, were carried out. Results confirm the existence of at least two quartz-rich sandstone lithofacies as potential geothermal reservoirs. In the principal settlement in this area, Cerro Sombrero township (1,800 population), the annual average temperature is 6.4°C, requiring constant domestic heating which, at present comes exclusively from natural gas. The study shows

  4. Low back pain and lumbar angles in Turkish coal miners

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sarikaya, S.; Ozdolap, S.; Gumustas, S.

    This study was designed to assess the incidence of low back pain among Turkish coal miners and to investigate the relationship between angles of the lumbar spine and low back pain in coal miners. Fifty underground workers (Group I) and 38 age-matched surface workers (Group II) were included in the study. All the subjects were asked about low back pain in the past 5 years. The prevalence of low back pain was higher in Group I than in Group II (78.0%, 32.4%, respectively, P {lt} 0.001). The results of the study showed that low back pain occurred in 78.0% ofmore » Turkish coal miners. Although the nature of the occupation may have influenced coal miners' lumbar spinal curvature, lumbar angles are not a determinant for low back pain in this population. Further extensive studies involving ergonomic measurements are needed to validate our results for Turkish coal mining industry.« less

  5. Binding of volatile anesthetics to serum albumin: measurements of enthalpy and solvent contributions.

    PubMed

    Sawas, Abdul H; Pentyala, Srinivas N; Rebecchi, Mario J

    2004-10-05

    This study directly examines the enthalpic contributions to binding in aqueous solution of closely related anesthetic haloethers (desflurane, isoflurane, enflurane, and sevoflurane), a haloalkane (halothane), and an intravenous anesthetic (propofol) to bovine and human serum albumin (BSA and HSA) using isothermal titration calorimetry. Binding to serum albumin is exothermic, yielding enthalpies (DeltaH(obs)) of -3 to -6 kcal/mol for BSA with a rank order of apparent equilibrium association constants (K(a) values): desflurane > isoflurane approximately enflurane > halothane >or= sevoflurane, with the differences being largely ascribed to entropic contributions. Competition experiments indicate that volatile anesthetics, at low concentrations, share the same sites in albumin previously identified in crystallographic and photo-cross-linking studies. The magnitude of the observed DeltaH increased linearly with increased reaction temperature, reflecting negative changes in heat capacities (DeltaC(p)). These -DeltaC(p) values significantly exceed those calculated for burial of each anesthetic in a hydrophobic pocket. The enhanced stabilities of the albumin/anesthetic complexes and -DeltaC(p) are consistent with favorable solvent rearrangements that promote binding. This idea is supported by substitution of D(2)O for H(2)O that significantly reduces the favorable binding enthalpy observed for desflurane and isoflurane, with an opposing increase of DeltaS(obs). From these results, we infer that solvent restructuring, resulting from release of water weakly bound to anesthetic and anesthetic-binding sites, is a dominant and favorable contributor to the enthalpy and entropy of binding to proteins.

  6. Prevalence and Genetic Diversity of Enterococcus faecalis Isolates from Mineral Water and Spring Water in China.

    PubMed

    Wei, Lei; Wu, Qingping; Zhang, Jumei; Guo, Weipeng; Chen, Moutong; Xue, Liang; Wang, Juan; Ma, Lianying

    2017-01-01

    Enterococcus faecalis is an important opportunistic pathogen which is frequently detected in mineral water and spring water for human consumption and causes human urinary tract infections, endocarditis and neonatal sepsis. The aim of this study was to determine the prevalence, virulence genes, antimicrobial resistance and genetic diversity of E. faecalis from mineral water and spring water in China. Of 314 water samples collected from January 2013 to January 2014, 48 samples (15.3%) were contaminated E. faecalis . The highest contamination rate occurred in activated carbon filtered water of spring water (34.5%), followed by source water of spring water (32.3%) and source water of mineral water (6.4%). The virulence gene test of 58 E. faecalis isolates showed that the detection rates of asa1 , ace , cylA , gelE and hyl were 79.3, 39.7, 0, 100, 0%, respectively. All 58 E. faecalis isolates were not resistant to 12 kinds of antibiotics (penicillin, ampicillin, linezolid, quinupristin/dalfopristin, vancomycin, gentamicin, streptomycin, ciprofloxacin, levofloxacin, norfloxacin, nitrofurantoin, and tetracycline). Enterobacterial repetitive intergenic consensus-PCR classified 58 isolates and three reference strains into nine clusters with a similarity of 75%. This study is the first to investigate the prevalence of E. faecalis in mineral water and spring water in China. The results of this study suggested that spring water could be potential vehicles for transmission of E. faecalis .

  7. Aldosterone changes after consumption of a sodium-bicarbonated mineral water in humans. A four-way randomized controlled trial.

    PubMed

    Toxqui, Laura; Vaquero, M Pilar

    2016-12-01

    Abnormally high aldosterone levels are associated to hypertension and cardiovascular disease. A sodium-rich mineral water was previously shown to reduce several markers of cardiovascular risk and did not increase blood pressure in healthy adults. We aimed to study the effects of consuming the same mineral water compared to a control water on aldosterone levels, and if the effects vary due to the presence of meal in healthy adults. The design was a four-way randomized controlled crossover 120-min-postprandial trial. Twenty-one healthy men and women participated in the study. Exclusion criteria are diabetes, hypertension, and being a usual consumer of carbonic mineral water. Two different mineral waters, high-sodium and bicarbonate mineral water (BW, sodium, 1 g/L; bicarbonate, 2 g/L) and low-mineral content control water (CW), were consumed with or without a standard meal (500 mL per meal). Statistical analysis was performed by repeated measures ANOVA. The results are as follows: serum sodium did not vary, and serum potassium decreased throughout the assay (p = 0.01) without water influence. Consumption of BW significantly decreased aldosterone levels at 30 (p = 0.046), 60 (p = 0.009), and 120 (p = 0.025) min when consumed alone, and at 120 min (p = 0.019) when consumed with meal, compared to CW. Moreover, the effect of BW on aldosterone levels was significant in women but not in men. In conclusion, consumption of a sodium-bicarbonated mineral water, in presence or absence of meal, induces aldosterone inhibition in healthy women, which is suggested to be a physiological response that protects them against hypertension. This trial is registered at clinicaltrial.gov as NCT01334840.

  8. Mineral Dissolution and Precipitation due to Carbon Dioxide-Water-Rock Interactions: The Significance of Accessory Minerals in Carbonate Reservoirs (Invited)

    NASA Astrophysics Data System (ADS)

    Kaszuba, J. P.; Marcon, V.; Chopping, C.

    2013-12-01

    Accessory minerals in carbonate reservoirs, and in the caprocks that seal these reservoirs, can provide insight into multiphase fluid (CO2 + H2O)-rock interactions and the behavior of CO2 that resides in these water-rock systems. Our program integrates field data, hydrothermal experiments, and geochemical modeling to evaluate CO2-water-rock reactions and processes in a variety of carbonate reservoirs in the Rocky Mountain region of the US. These studies provide insights into a wide range of geologic environments, including natural CO2 reservoirs, geologic carbon sequestration, engineered geothermal systems, enhanced oil and gas recovery, and unconventional hydrocarbon resources. One suite of experiments evaluates the Madison Limestone on the Moxa Arch, Southwest Wyoming, a sulfur-rich natural CO2 reservoir. Mineral textures and geochemical features developed in the experiments suggest that carbonate minerals which constitute the natural reservoir will initially dissolve in response to emplacement of CO2. Euhedral, bladed anhydrite concomitantly precipitates in response to injected CO2. Analogous anhydrite is observed in drill core, suggesting that secondary anhydrite in the natural reservoir may be related to emplacement of CO2 into the Madison Limestone. Carbonate minerals ultimately re-precipitate, and anhydrite dissolves, as the rock buffers the acidity and reasserts geochemical control. Another suite of experiments emulates injection of CO2 for enhanced oil recovery in the Desert Creek Limestone (Paradox Formation), Paradox Basin, Southeast Utah. Euhedral iron oxyhydroxides (hematite) precipitate at pH 4.5 to 5 and low Eh (approximately -0.1 V) as a consequence of water-rock reaction. Injection of CO2 decreases pH to approximately 3.5 and increases Eh by approximately 0.1 V, yielding secondary mineralization of euhedral pyrite instead of iron oxyhydroxides. Carbonate minerals also dissolve and ultimately re-precipitate, as determined by experiments in the

  9. Enthalpies of a binary alloy during solidification

    NASA Technical Reports Server (NTRS)

    Poirier, D. R.; Nandapurkar, P.

    1988-01-01

    The purpose of the paper is to present a method of calculating the enthalpy of a dendritic alloy during solidification. The enthalpies of the dendritic solid and interdendritic liquid of alloys of the Pb-Sn system are evaluated, but the method could be applied to other binaries, as well. The enthalpies are consistent with a recent evaluation of the thermodynamics of Pb-Sn alloys and with the redistribution of solute in the same during dendritic solidification. Because of the heat of mixing in Pb-Sn alloys, the interdendritic liquid of hypoeutectic alloys (Pb-rich) of less than 50 wt pct Sn has enthalpies that increase as temperature decreases during solidification.

  10. Water in Nominally Anhydrous Minerals from Nakhlites and Shergottites

    NASA Technical Reports Server (NTRS)

    Peslier, Anne H.

    2013-01-01

    Estimating the amount of water in the interior of terrestrial planets has tremendous implications on our understanding of solar nebula evolution, planet formation and geological history, and extraterrestrial volcanism. Mars has been a recent focus of such enquiry with complementary datasets from spacecrafts, rovers and martian meteorite studies. In planetary interiors, water can be dissolved in fluids or melts and hydrous phases, but can also be locked as protons attached to structural oxygen in lattice defects in nominally anhydrous minerals (NAM) such as olivine, pyroxene, or feldspar [1-3]. Measuring water in Martian meteorite NAM is challenging because the minerals are fragile and riddled with fractures from impact processes that makes them break apart during sample processing. Moreover, curing the sample in epoxy causes problems for the two main water analysis techniques, Fourier transform infrared spectrometry (FTIR) and secondary ionization mass spectrometry (SIMS). Measurements to date have resulted in a heated debate on how much water the mantle of Mars contains. SIMS studies of NAM [4], amphiboles [5], and apatites [6-8] from Martian meteorites report finding enough water in these phases to infer that the martian mantle is as hydrous as that of the Earth. On the other hand, a SIMS study of glass in olivine melt inclusions from shergottites concludes that the Martian mantle is much drier [9]. The latter interpretation is also supported by the fact that most martian hydrous minerals generally have the relevant sites filled with Cl and F instead of H [10,11]. As for experimental results, martian basalt compositions can be reproduced using water as well as Cl in the parent melts [12,13]. Here FTIR is used to measure water in martian meteorite minerals in order to constrain the origin of the distribution of water in martian meteorite phases.

  11. Computational investigation of enthalpy-entropy compensation in complexation of glycoconjugated bile salts with β-cyclodextrin and analogs.

    PubMed

    Tidemand, Kasper D; Schönbeck, Christian; Holm, René; Westh, Peter; Peters, Günther H

    2014-09-18

    The inclusion complexes of glycoconjugated bile salts with β-cyclodextrin (β-CD) and 2-hydroxypropyl-β-cyclodextrins (HP-β-CD) in aqueous solution were investigated by molecular dynamics simulations to provide a molecular explanation of the experimentally observed destabilizing effect of the HP substituents. Good agreement with experimental data was found with respect to penetration depths of CDs. An increased degree of HP substitution (DS) resulted in an increased probability of blocking the cavity opening, thereby hindering the bile salt from entering CD. Further, the residence time of water molecules in the cavity increased with the DS. Release of water from the cavity resulted in a positive enthalpy change, which correlates qualitatively with the experimentally determined increase in complexation enthalpy and contributes to the enthalpy-entropy compensation. The positive change in complexation entropy with DS was not able to compensate for this unfavorable change in enthalpy induced by the HP substituents, resulting in a destabilizing effect. This was found to originate from fixation of the HP substituents and decreased free rotation of the bile salts within the CD cavities.

  12. Precise determination of water exchanges on a mineral surface

    DOE PAGES

    Stack, Andrew G.; Borreguero, Jose M.; Prisk, Timothy R.; ...

    2016-10-03

    Solvent exchanges on solid surfaces and dissolved ions are a fundamental property important for understanding chemical reactions, but the rates of fast exchanges are poorly constrained. In this paper, we probed the diffusional motions of water adsorbed onto nanoparticles of the mineral barite (BaSO 4) using quasi-elastic neutron scattering (QENS) and classical molecular dynamics (MD) to reveal the complex dynamics of water exchange along mineral surfaces. QENS data as a function of temperature and momentum transfer (Q) were fit using scattering functions derived from MD trajectories. The simulations reproduce the dynamics measured in the experiments at ambient temperatures, but asmore » temperature is lowered the simulations overestimate slower motions. Decomposition of the MD-computed QENS intensity into contributions from adsorbed and unbound water shows that the majority of the signal arises from adsorbed species, although the dynamics of unbound water cannot be dismissed. The mean residence times of water on each of the four surface sites present on the barite {001} were calculated using MD: at room temperature the low barium site is 194 ps, whereas the high barium site contains two distributions of motions at 84 and 2.5 ps. These contrast to 13 ps residence time on both sulfate sites, with an additional surface diffusion exchange of 66 ps. Surface exchanges are similar to those of the aqueous ions calculated using the same force field: Ba aq 2+ is 208 ps and SO 4aq 2- is 5.8 ps. Finally, this work demonstrates how MD can be a reliable method to deconvolute solvent exchange reactions when quantitatively validated by QENS measurements.« less

  13. Enthalpy of Mixing in Al–Tb Liquid

    DOE PAGES

    Zhou, Shihuai; Tackes, Carl; Napolitano, Ralph

    2017-06-21

    The liquid-phase enthalpy of mixing for Al$-$Tb alloys is measured for 3, 5, 8, 10, and 20 at% Tb at selected temperatures in the range from 1364 to 1439 K. Methods include isothermal solution calorimetry and isoperibolic electromagnetic levitation drop calorimetry. Mixing enthalpy is determined relative to the unmixed pure (Al and Tb) components. The required formation enthalpy for the Al3Tb phase is computed from first-principles calculations. Finally, based on our measurements, three different semi-empirical solution models are offered for the excess free energy of the liquid, including regular, subregular, and associate model formulations. These models are also compared withmore » the Miedema model prediction of mixing enthalpy.« less

  14. Enthalpy of phase transitions of lactams

    NASA Astrophysics Data System (ADS)

    Emel'yanenko, V. N.; Verevkin, S. P.; Ralys, R. V.; Turovtsev, V. V.; Orlov, V. Yu.

    2012-10-01

    The transpiration method is used to measure the temperature dependences of the vapors pressures of azacyclobutan-2-one (I, CAS 930-21-2) azacyclohexan-2-one (II, CAS 675-20-7); azacyclooctan-2-one (III, CAS 673-66-5); azacyclononan-2-one (IV, CAS 935-30-8) and azacyclotridecan-2-one (V, CAS 947-04-6). Enthalpies of sublimation and vaporisation are determined. The temperatures and enthalpies of fusion of compounds (I, III-V) are found by means of differential scanning calorimetry. The dependences of the enthalpies of vaporisation of lactones, lactams, cycloalkanes, cycloalkanones on the size of a cycle are analyzed.

  15. Coupling geophysical investigation with hydrothermal modeling to constrain the enthalpy classification of a potential geothermal resource.

    USGS Publications Warehouse

    White, Jeremy T.; Karakhanian, Arkadi; Connor, Chuck; Connor, Laura; Hughes, Joseph D.; Malservisi, Rocco; Wetmore, Paul

    2015-01-01

    An appreciable challenge in volcanology and geothermal resource development is to understand the relationships between volcanic systems and low-enthalpy geothermal resources. The enthalpy of an undeveloped geothermal resource in the Karckar region of Armenia is investigated by coupling geophysical and hydrothermal modeling. The results of 3-dimensional inversion of gravity data provide key inputs into a hydrothermal circulation model of the system and associated hot springs, which is used to evaluate possible geothermal system configurations. Hydraulic and thermal properties are specified using maximum a priori estimates. Limited constraints provided by temperature data collected from an existing down-gradient borehole indicate that the geothermal system can most likely be classified as low-enthalpy and liquid dominated. We find the heat source for the system is likely cooling quartz monzonite intrusions in the shallow subsurface and that meteoric recharge in the pull-apart basin circulates to depth, rises along basin-bounding faults and discharges at the hot springs. While other combinations of subsurface properties and geothermal system configurations may fit the temperature distribution equally well, we demonstrate that the low-enthalpy system is reasonably explained based largely on interpretation of surface geophysical data and relatively simple models.

  16. A Simple Experiment for Determining Vapor Pressure and Enthalpy of Vaporization of Water.

    ERIC Educational Resources Information Center

    Levinson, Gerald S.

    1982-01-01

    Laboratory procedures, calculations, and sample results are described for a freshman chemistry experiment in which the Clausius-Clapeyron equation is introduced as a means of describing the variation of vapor pressure with temperature and for determining enthalpy of vaporization. (Author/SK)

  17. Interior ice/mineral/water interface dynamics (Invited)

    NASA Astrophysics Data System (ADS)

    Rempel, A. W.

    2009-12-01

    The search for life begins with the search for liquid water. In our solar system, persistent water reservoirs are invariably found together with ice. On Earth, organisms have evolved to thrive at sub-zero temperatures in ice-bound habitats that have numerous analogues throughout our solar system and beyond. To assess the potential for life requires a thorough investigation of the dynamic interactions within these deposits. Well-established thermodynamic principles govern the stable coexistence of premelted liquid at the interface between ice and other minerals. Foreign constituents are efficiently rejected from the ice crystal lattice and are concentrated in residual liquid regions instead. This gains added importance with the recognition that the most fundamental requirements for survival include a food source and the removal of waste. This talk reviews the astrobiological implications of the availability, behavior, and properties of liquid water in association with the interiors of icy bodies and ice-mineral interfacial regions.

  18. Calculating the enthalpy of vaporization for ionic liquid clusters.

    PubMed

    Kelkar, Manish S; Maginn, Edward J

    2007-08-16

    Classical atomistic simulations are used to compute the enthalpy of vaporization of a series of ionic liquids composed of 1-alkyl-3-methylimidazolium cations paired with the bis(trifluoromethylsulfonyl)imide anion. The calculations show that the enthalpy of vaporization is lowest for neutral ion pairs. The enthalpy of vaporization increases by about 40 kJ/mol with the addition of each ion pair to the vaporizing cluster. Non-neutral clusters have much higher vaporization enthalpies than their neutral counterparts and thus are not expected to make up a significant fraction of volatile species. The enthalpy of vaporization increases slightly as the cation alkyl chain length increases and as temperature decreases. The calculated vaporization enthalpies are consistent with two sets of recent experimental measurements as well as with previous atomistic simulations.

  19. A DFT study on the enthalpies of thermite reactions and enthalpies of formation of metal composite oxide

    NASA Astrophysics Data System (ADS)

    Zhang, Yu-ying; Wang, Meng-jie; Chang, Chun-ran; Xu, Kang-zhen; Ma, Hai-xia; Zhao, Feng-qi

    2018-05-01

    The standard thermite reaction enthalpies (ΔrHmθ) for seven metal oxides were theoretically analyzed using density functional theory (DFT) under five different functional levels, and the results were compared with experimental values. Through the comparison of the linear fitting constants, mean error and root mean square error, the Perdew-Wang functional within the framework of local density approximation (LDA-PWC) and Perdew-Burke-Ernzerhof exchange-correlation functional within the framework of generalized gradient approximation (GGA-PBE) were selected to further calculate the thermite reaction enthalpies for metal composite oxides (MCOs). According to the Kirchhoff formula, the standard molar reaction enthalpies for these MCOs were obtained and their standard molar enthalpies of formation (ΔfHmθ) were finally calculated. The results indicated that GGA-PBE is the most suitable one out of the total five methods to calculate these oxides. Tungstate crystals present the maximum deviation of the enthalpies of thermite reactions for MCOs and these of their physical metal oxide mixtures, but ferrite crystals are the minimum. The correlation coefficients are all above 0.95, meaning linear fitting results are very precise. And the molar enthalpies of formation for NiMoO4, CuMoO4, PbZrO3 (Pm/3m), PbZrO3 (PBA2), PbZrO3 (PBam), MgZrO3, CdZrO3, MnZrO3, CuWO4 and Fe2WO6 were first obtained as -1078.75, -1058.45, -1343.87, -1266.54, -1342.29, -1333.03, -1210.43, -1388.05, -1131.07 and - 1860.11 kJ·mol-1, respectively.

  20. Magnetic Mineral diagenesis in changing water environments in the Black Sea since ˜41.6 ka

    NASA Astrophysics Data System (ADS)

    Liu, Jiabo; Nowaczyk, Norbert; Frank, Ute; Arz, Helge

    2017-04-01

    Magnetic mineral diagenesis plays a key role in the global iron cycle. To understand the authigenic magnetic mineral formation by diagenesis is also fundamentally important for the interpretation of environmental magnetic as well as paleomagnetic signals. Core MSM33-55-1, recovered from the SW Black Sea, was subjected to rock-magnetic and SEM studies. The results demonstrate that four different magnetic mineral assemblages associated to specific water conditions can be observed. Between ˜41.6 ka and ˜19 ka, magnetite and greigite are alternatively in dominance in the sediment. Due to low organic matter input during the late MIS 3 and the last glacial maximum (LGM), oxygenated bottom water in the Black Sea was favourable for preserving detrital magnetite. Greigite in this interval have irregular shapes and assemble in spots, which were formed in a micro environment with limited sulfate availability. Between ˜19 ka and ˜16.5 ka, black layers were deposited as a result of organic matter accumulation induced by productivity blooming and riverine discharge soaring after the LGM. Hence less oxygenated bottom water conditions developed, and more fine grained greigite was formed. After melt-water pulse (MWP) events (˜16.5 ka), both primary productivity and the sea level were continuously rising until ˜8.3 ka, leading to the depletion of oxygen in bottom water. In addition to greigite, pyrite was also formed and gradually in dominance as approaching the Holocene. The influx of salt water masses from the Mediterranean Sea after ˜8.3 ka contributed to the establishment of the anoxic Black Sea, which resulted in the formation of ubiquitous frambiods of pyrite. Additionally, bacterial magnetic minerals are likely present in the sediment younger than ˜8.3 ka as indicated by rock magnetic results. In this paper, four different magnetic mineral assemblages, reflecting gradual changes from an oxic to an anoix Black Sea, were identified, yielding insights into the relation

  1. Water Footprint in Nitrate Vulnerable Zones: Mineral vs. Organic Fertilization.

    NASA Astrophysics Data System (ADS)

    Castellanos Serrano, María Teresa; Requejo Mariscal, María Isabel; Villena Gordo, Raquel; Cartagena Causapé, María Carmen; Arce Martínez, Augusto; Ribas Elcorobarrutia, Francisco; María Tarquis Alfonso, Ana

    2017-04-01

    In intensive agriculture, it is necessary to apply irrigation and fertilizers to increase the crop yield. An optimization of water and N application is necessary. An excess of irrigation implies nitrates washing which would contribute to the contamination of the groundwater. An excess of N, besides affecting the yield and fruit quality, causes serious environmental problems. Nitrate vulnerable zones (NVZs) are areas designated as being at risk from agricultural nitrate pollution. They include around 16% of land in Spain and in Castilla-La Mancha, the area studied, represents 45% of the total land. In several zones, the N content of the groundwater could be approximately 140 mg L-1, or even higher [1]. The input of nitrogen fertilizers (mineral or organic), applied with a poor management, could be increased considerably the pollution risks. The water footprint (WF) is as indicator for the total volume of direct and indirect freshwater used, consumed and/or polluted [2]. The WF includes both consumptive water use: blue water (volume of surface and groundwater consumed) and green water (rainwater consumed)). A third element is the water required to assimilate pollution (grey water) [2]. Under semiarid conditions with low irrigation water quality, green WF is zero because the effective rainfall is negligible. Blue WF includes: i) extra consumption or irrigation water that the farmer has to apply to compensate the fail of uniformity on discharge of drips, ii) percolation out of control or salts leaching, which depends on the salt tolerance of the crop, soil and quality of irrigation water, to ensure the fruit yield. In the NVZs, the major concern is grey WF, because the irrigation and nitrogen dose have to be adjusted to the crop needs in order to minimize nitrate pollution. This study focus on the assessment of mineral and organic fertilization on WF in a fertirrigated melon crop under semiarid conditions with a low water quality. During successive years, a melon crop

  2. Enthalpies of Formation of Hydrazine and Its Derivatives.

    PubMed

    Dorofeeva, Olga V; Ryzhova, Oxana N; Suchkova, Taisiya A

    2017-07-20

    Enthalpies of formation, Δ f H 298 ° , in both the gas and condensed phase, and enthalpies of sublimation or vaporization have been estimated for hydrazine, NH 2 NH 2 , and its 36 various derivatives using quantum chemical calculations. The composite G4 method has been used along with isodesmic reaction schemes to derive a set of self-consistent high-accuracy gas-phase enthalpies of formation. To estimate the enthalpies of sublimation and vaporization with reasonable accuracy (5-20 kJ/mol), the method of molecular electrostatic potential (MEP) has been used. The value of Δ f H 298 ° (NH 2 NH 2 ,g) = 97.0 ± 3.0 kJ/mol was determined from 75 isogyric reactions involving about 50 reference species; for most of these species, the accurate Δ f H 298 ° (g) values are available in Active Thermochemical Tables (ATcT). The calculated value is in excellent agreement with the reported results of the most accurate models based on coupled cluster theory (97.3 kJ/mol, the average of six calculations). Thus, the difference between the values predicted by high-level theoretical calculations and the experimental value of Δ f H 298 ° (NH 2 NH 2 ,g) = 95.55 ± 0.19 kJ/mol recommended in the ATcT and other comprehensive reference sources is sufficiently large and requires further investigation. Different hydrazine derivatives have been also considered in this work. For some of them, both the enthalpy of formation in the condensed phase and the enthalpy of sublimation or vaporization are available; for other compounds, experimental data for only one of these properties exist. Evidence of accuracy of experimental data for the first group of compounds was provided by the agreement with theoretical Δ f H 298 ° (g) value. The unknown property for the second group of compounds was predicted using the MEP model. This paper presents a systematic comparison of experimentally determined enthalpies of formation and enthalpies of sublimation or vaporization with the results of

  3. A nearly water-saturated mantle transition zone inferred from mineral viscosity.

    PubMed

    Fei, Hongzhan; Yamazaki, Daisuke; Sakurai, Moe; Miyajima, Nobuyoshi; Ohfuji, Hiroaki; Katsura, Tomoo; Yamamoto, Takafumi

    2017-06-01

    An open question for solid-earth scientists is the amount of water in Earth's interior. The uppermost mantle and lower mantle contain little water because their dominant minerals, olivine and bridgmanite, have limited water storage capacity. In contrast, the mantle transition zone (MTZ) at a depth of 410 to 660 km is considered to be a potential water reservoir because its dominant minerals, wadsleyite and ringwoodite, can contain large amounts of water [up to 3 weight % (wt %)]. However, the actual amount of water in the MTZ is unknown. Given that water incorporated into mantle minerals can lower their viscosity, we evaluate the water content of the MTZ by measuring dislocation mobility, a property that is inversely proportional to viscosity, as a function of temperature and water content in ringwoodite and bridgmanite. We find that dislocation mobility in bridgmanite is faster by two orders of magnitude than in anhydrous ringwoodite but 1.5 orders of magnitude slower than in water-saturated ringwoodite. To fit the observed mantle viscosity profiles, ringwoodite in the MTZ should contain 1 to 2 wt % water. The MTZ should thus be nearly water-saturated globally.

  4. Spectroscopic studies of water and water/regolith mixtures on planetary surfaces at low temperatures. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Clark, R. N.

    1980-01-01

    New reflectance spectra of Ganymede, Europe, Callisto, Io, Saturn's rings, and Mars were obtained. The new data is combined with data covering other spectral regions for compositional interpretation. The spectral properties of water and mixtures of water plus other minerals were studied in the laboratory at the low temperatures typical of Mars, the Galilean satellites, and Saturn's rings. High precision reflectance spectra of water ice were studied.

  5. Geochemistry and origins of mineralized waters in the Floridan aquifer system, northeastern Florida

    USGS Publications Warehouse

    Phelps, G.G.

    2001-01-01

    Increases in chloride concentration have been observed in water from numerous wells tapping the Floridan aquifer system in northeastern Florida. Although most increases have been in the eastern part of Duval County, Florida, no spatial pattern in elevated chloride concentrations is discernible. Possible sources of the mineralized water include modern seawater intrusion; unflushed Miocene-to-Pleistocene-age seawater or connate water in aquifer sediments; or mineralized water from deeper zones of the aquifer system or from formations beneath the Floridan aquifer system. The purpose of this study was to document the chemical and isotopic characteristics of water samples from various aquifer zones, and from geochemical and hydrogeologic data, to infer the source of the increased mineralization. Water samples were collected from 53 wells in northeastern Florida during 1997-1999. Wells tapped various zones of the aquifer including: the Fernandina permeable zone (FPZ), the upper zone of the Lower Floridan aquifer (UZLF), the Upper Floridan aquifer (UFA), and both the UFA and the UZLF. Water samples were analyzed for major ions and trace constituents and for isotopes of carbon, oxygen, hydrogen, sulfur, strontium, chlorine, and boron. Samples of rock from the aquifer were analyzed for isotopes of oxygen, carbon, and strontium. In general, water from various aquifer zones cannot be differentiated based on chemistry, except for water from FPZ wells. Major-ion concentrations vary as much within the upper zone of the Lower Floridan aquifer and the Upper Floridan aquifer as between these two zones. Simple models of mixing between fresh ground water and either modern seawater or water from the FPZ as a mineralized end member show that many water samples from the UZLF aquifer and the UFA are enriched in bicarbonate, calcium, magnesium, sulfate, fluoride, and silica and are depleted in sodium and potassium (as compared to concentrations predicted by simple mixing). Chemical mass

  6. Low-Fe(III) Greenalite Was a Primary Mineral From Neoarchean Oceans

    NASA Astrophysics Data System (ADS)

    Johnson, Jena E.; Muhling, Janet R.; Cosmidis, Julie; Rasmussen, Birger; Templeton, Alexis S.

    2018-04-01

    Banded iron formations (BIFs) represent chemical precipitation from Earth's early oceans and therefore contain insights into ancient marine biogeochemistry. However, BIFs have undergone multiple episodes of alteration, making it difficult to assess the primary mineral assemblage. Nanoscale mineral inclusions from 2.5 billion year old BIFs and ferruginous cherts provide new evidence that iron silicates were primary minerals deposited from the Neoarchean ocean, contrasting sharply with current models for BIF inception. Here we used multiscale imaging and spectroscopic techniques to characterize the best preserved examples of these inclusions. Our integrated results demonstrate that these early minerals were low-Fe(III) greenalite. We present potential pathways in which low-Fe(III) greenalite could have formed through changes in saturation state and/or iron oxidation and reduction. Future constraints for ancient ocean chemistry and early life's activities should include low-Fe(III) greenalite as a primary mineral in the Neoarchean ocean.

  7. Development of an LC-MS/MS method for studying migration characteristics of acetaldehyde in polyethylene terephthalate (PET)-packed mineral water.

    PubMed

    Baumjohann, Nina; Harms, Diedrich

    2015-01-01

    During storage, acetaldehyde migration from polyethylene terephthalate (PET) bottles can affect the quality of mineral water even in the low µg l(-1) range negatively, as it features a fruity or plastic-like off-flavour. For a sensitive and fast analysis of acetaldehyde in mineral water, a new analysis method of 2,4-dinitrophenylhydrazine (DNPH) derivatisation followed by HPLC-electrospray tandem mass spectrometry (ESI-MS/MS) was developed. Acetaldehyde was directly derivatised in the mineral water sample avoiding extraction and/or pre-concentration steps and then analysed by reversed-phase HPLC-ESI-MS/MS using multiple reaction monitoring mode (MRM). Along with method development, the optimum molar excess of DNPH in contrast to acetaldehyde was studied for the mineral water matrix, because no specific and robust data were yet available for this critical parameter. Best results were obtained by using a calibration via the derivatisation reaction. Without any analyte enrichment or extraction, an LOD of 0.5 µg l(-1) and an LOQ of 1.9 µg l(-1) were achieved. Using the developed method, mineral water samples packed in PET bottles from Germany were analysed and the correlation between the acetaldehyde concentration and other characteristics of the samples was evaluated illustrating the applicability of the method. Besides a relationship between bottle size and CO2 content of the mineral water and acetaldehyde migration, a correlation with acetaldehyde migration and the material composition of the bottle, e.g. recycled PET, was noted. Investigating the light influence on the acetaldehyde migration with a newly developed, reproducible light exposure setup, a significant increase of the acetaldehyde concentration in carbonated mineral water samples was observed.

  8. Cavitation pitting and erosion of aluminum 6061-T6 in mineral oil water

    NASA Technical Reports Server (NTRS)

    Rao, B. C. S.; Buckley, D. H.

    1983-01-01

    Cavitation erosion studies of aluminum 6061-T6 in mineral oil and in ordinary tap water are presented. The maximum erosion rate (MDPR, or mean depth of penetration rate) in mineral oil was about four times that in water. The MDPR in mineral oil decreased continuously with time, but the MDPR in water remained approximately constant. The cavitation pits in mineral oil were of smaller diameter and depth than the pits in water. Treating the pits as spherical segments, we computed the radius r of the sphere. The logarithm of h/a, where h is the pit depth and 2a is the top width of the pit, was linear when plotted against the logarithm of 2r/h - 1.

  9. The Molecular Origin of Enthalpy/Entropy Compensation in Biomolecular Recognition.

    PubMed

    Fox, Jerome M; Zhao, Mengxia; Fink, Michael J; Kang, Kyungtae; Whitesides, George M

    2018-05-20

    Biomolecular recognition can be stubborn; changes in the structures of associating molecules, or the environments in which they associate, often yield compensating changes in enthalpies and entropies of binding and no net change in affinities. This phenomenon-termed enthalpy/entropy (H/S) compensation-hinders efforts in biomolecular design, and its incidence-often a surprise to experimentalists-makes interactions between biomolecules difficult to predict. Although characterizing H/S compensation requires experimental care, it is unquestionably a real phenomenon that has, from an engineering perspective, useful physical origins. Studying H/S compensation can help illuminate the still-murky roles of water and dynamics in biomolecular recognition and self-assembly. This review summarizes known sources of H/ S compensation (real and perceived) and lays out a conceptual framework for understanding and dissecting-and, perhaps, avoiding or exploiting-this phenomenon in biophysical systems.

  10. Enthalpy of mixing of liquid Co–Sn alloys

    PubMed Central

    Yakymovych, A.; Fürtauer, S.; Elmahfoudi, A.; Ipser, H.; Flandorfer, H.

    2014-01-01

    A literature overview of enthalpy of mixing data for liquid Co–Sn alloys shows large scattering but no clear temperature dependence. Therefore drop calorimetry was performed in the Co–Sn system at twelve different temperatures in 100 K steps in the temperature range (673 to 1773) K. The integral enthalpy of mixing was determined starting from 1173 K and fitted to a standard Redlich–Kister polynomial. In addition, the limiting partial molar enthalpy of Co in Sn was investigated by small additions of Co to liquid Sn at temperatures (673 to 1773) K. The integral and partial molar enthalpies of the Co–Sn system generally show an exothermic mixing behavior. Significant temperature dependence was detected for the enthalpies of mixing. The minimum integral enthalpy values vary with rising temperature from approx. −7820 J/mol at T = 1173 K to −1350 J/mol at T = 1773 K; the position of the minimum is between (59 and 61) at.% Co. The results are discussed and compared with literature data available for this system. X-ray studies and scanning electron microscopy of selected alloys obtained from the calorimetric measurements were carried out in order to check the completeness of the solution process. PMID:24994940

  11. Determination of the origin and magnitude of Al/Si ordering enthalpy in framework aluminosilicates from ab initio calculations

    NASA Astrophysics Data System (ADS)

    McConnell, J. D. C.; De Vita, A.; Kenny, S. D.; Heine, V.

    Ab initio total energy calculations based on a new optimised oxygen pseudopotential has been used to determine the enthalpy of disorder for the exchange of Al and Si in tetrahedral coordination in simple derivative aluminosilicate structures based on the high temperature tridymite structure. The problem has been studied as a function of defect interaction, and defect concentration, and the results indicate that the energy for Al/Al neighbouring tetrahedra can be assigned primarily to two effects, the first, a coulombic effect, associated with the disturbed charge distribution, and the second associated with the strain related to misfit due to the very different dimensions of the Si and Al containing tetrahedra. In practice each of these effects contributes approximately 0.2 eV per Al-Al neighbour to the overal disorder enthalpy. These simple results were obtained after a careful study of possible chemical interaction between adjacent Al/Si containing tetrahedra which showed that chemical interaction was effectively absent. Since individual Al/Si tetrahedra proved to be discrete entities that are individually heavily screened by the shared oxygens it follows that coulombic and strain effects in disorder effectively account for the whole of the disorder enthalpy. The complete set of results have been used to establish new criteria for the structure and disorder enthalpies of the feldspar group of minerals and their long period derivatives.

  12. Magnesium-rich minerals in sediment and suspended particulates of South Florida water bodies: implications for turbidity.

    PubMed

    Harris, W G; Fisher, M M; Cao, X; Osborne, T; Ellis, L

    2007-01-01

    Fine sediments in shallow water bodies such as Lake Okeechobee are prone to resuspension. Predominantly inorganic "mud" sediment that covers approximately 670 km2 of the lake has been recognized as a persistent source of turbidity. The objective of this study was to determine if mineral components of sediments in Lake Okeechobee and water conveyances of the northern Everglades also occur as suspended sediment and hence constitute a potential abiotic contributor to turbidity. Sediment samples were collected from nine stations within the lake and eight locations north of Water Conservation Area 2A in the Everglades. Water samples were also collected at selected locations. The silt and clay mineralogy of sediment and suspended particles was determined using X-ray diffraction, thermogravimetry, scanning-electron microscopy, energy-dispersive X-ray elemental microanalysis, and high-resolution transmission-electron microscopy. Clay fractions of the lake sediment contained the Mg silicate minerals sepiolite and palygorskite, along with smectite, dolomite, calcite, and kaolinite. Sediment silt fractions were dominated by carbonates and/or quartz, with smaller amounts of Ca phosphates and sepiolite. Mineralogy of the mud sediment was similar to that reported for geologic phosphate deposits. This suggests that the mud sediment might have accumulated by stream transport of minerals from these deposits. Suspended solids and mud-sediment mineralogy were similar, except that smectite was more abundant in suspended solids. Everglade samples also contained Mg-rich minerals. The small size, low density, and fibrous or platy nature of the prevalent mud sediment minerals make them an abiotic, hydrodynamically sensitive source of persistent turbidity in a shallow lake. Mitigation efforts focused exclusively on P-induced biogeochemical processes do not address the origin or effects of these minerals. Ecological management issues such as turbidity control, P retention, geologic P input

  13. Experimental Evidence of Low Density Liquid Water under Decompression

    NASA Astrophysics Data System (ADS)

    Shen, G.; Lin, C.; Sinogeikin, S. V.; Smith, J.

    2017-12-01

    Water is not only the most important substance for life, but also plays important roles in liquid science for its anomalous properties. It has been widely accepted that water's anomalies are not a result of simple thermal fluctuation, but are connected to the formation of various structural aggregates in the hydrogen bonding network. Among several proposed scenarios, one model of fluctuations between two different liquids has gradually gained traction. These two liquids are referred to as a low-density liquid (LDL) and a high-density liquid (HDL) with a coexistence line in the deeply supercooled regime at elevated pressure. The LDL-HDL transition ends with decreasing pressure at a liquid-liquid critical point (LLCP) with its Widom line extending to low pressures. Above the Widom line lies mostly HDL which is favored by entropy, while LDL, mostly lying below the Widom line, is favored by enthalpy in the tetrahedral hydrogen bonding network. The origin of water's anomalies can then be explained by the increase in structural fluctuations, as water is cooled down to deeply supercooled temperatures approaching the Widom line. Because both the LLCP and the LDL-HDL transition line lie in water's "no man's land" between the homogeneous nucleation temperature (TH, 232 K) and the crystallization temperature (TX, 150 K), the success of experiments exploring this region has been limited thus far. Using a rapid decompression technique integrated with in situ x-ray diffraction, we observe that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140-165K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. The change in crystallization rate with temperature indicates that the LDN is a LDL with its tetrahedrally-coordinated network fully developed and clearly linked to low-density amorphous ices. The observation of the tetrahedral LDL supports the two-liquid model for

  14. Networking and rheology of concentrated clay suspensions "matured" in mineral medicinal water.

    PubMed

    Aguzzi, Carola; Sánchez-Espejo, Rita; Cerezo, Pilar; Machado, José; Bonferoni, Cristina; Rossi, Silvia; Salcedo, Inmaculada; Viseras, César

    2013-09-10

    This work studied the influence of "maturation" conditions (time and agitation) on aggregation states, gel structure and rheological behaviour of a special kind of pharmaceutical semisolid products made of concentrated clay suspensions in mineral medicinal water. Maturation of the samples was carried out in distilled and sulphated mineral medicinal water, both in static conditions (without agitation) and with manual stirring once a week, during a maximum period of three months. At the measured pH interval (7.5-8.0), three-dimensional band-type networks resulting from face/face contacts were predominant in the laminar (disc-like) clay suspensions, whereas the fibrous (rod-like) particles formed micro-aggregates by van der Waals attractions. The high concentration of solids in the studied systems greatly determined their behaviour. Rod-like sepiolite particles tend to align the major axis in aggregates promoted by low shearing maturation, whereas aggregates of disc-like smectite particles did not have a preferential orientation and their complete swelling required long maturation time, being independent of stirring. Maturation of both kinds of suspensions resulted in improved rheological properties. Laminar clay suspensions became more structured with time, independently from static or dynamic maturation conditions, whereas for fibrous clay periodic agitation was also required. Rheological properties of the studied systems have been related to aggregation states and networking mechanisms, depending on the type of clay minerals constituents. Physical stability of the suspensions was not impaired by the specific composition of the Graena medicinal water. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schnell, Sondre K.; Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720; Department of Chemistry, Faculty of Natural Science and Technology, Norwegian University of Science and Technology, 4791 Trondheim

    2014-10-14

    We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate our method for binary mixtures of Weeks-Chandler-Anderson particles by comparing with conventional simulation techniques, as well as for a simple model that mimics a chemical reaction. The method considers small subsystems inside a large reservoir (i.e., the simulation box), and uses the construction of Hill to compute properties in the thermodynamic limit from small-scale fluctuations. Results obtainedmore » with the new method are in excellent agreement with those from previous methods. Especially for modeling chemical reactions, our method can be a valuable tool for determining reaction enthalpies directly from a single MD simulation.« less

  16. LOW BONE MINERAL DENSITY AMONG PATIENTS WITH NEWLY DIAGNOSED RHEUMATOID ARTHRITIS.

    PubMed

    Arain, Shafique Rehman; Riaz, Amir; Nazir, Lubna; Umer, Tahira Perveen; Rasool, Tabe

    2016-01-01

    Osteoporosis is an early and common feature in rheumatoid arthritis. Apart from other manifestations, Osteoporosis is an extra-articular manifestation of rheumatoid arthritis whichmay result in increased risk of fractures, morbidity mortality, and associated healthcare costs. This study evaluates bone mineral density changes in patients withrheumatoid arthritis of recent-onset. This cross sectional descriptive study was conducted in the Rheumatology Department of a tertiary care hospital in Karachi. Data was collected from 76 patients presenting with seropositive or seronegative rheumatoid arthritis. Bone mineral density of these patients measured at lumbar spine and hip by using dual energy x-ray absorptiometrys can. Variables like age, gender, BMI, menstrual status, disease duration, erythrocyte sedimentation rate, vitamin D level, clinical disease activity index and seropositivity for rheumatoid arthritis were measured along with outcome variables. A total of 104 patients fulfilling inclusion criteria were registered with 28 excluded from study. A mong the remaining 76 patients, 68 (89.50%) were female, with mean age of patients (with low bone mineral density) as 50.95 ± 7.87 years. Nineteen (25%) patients had low bone mineral density, 68.52% had low BMD at spine while 10.52% at hip and 21.05% at spine and hip both. Low bone mineral density was found higher in patients with seronegative 7 (50%) as compared to seropositive patients 12 (19.4%) (p-value 0.017), whereas low bone mineral d ensity was found higher 12 (70.6%) among post-menopausal women. Low BMD was found in 25% of patients at earlier stage of the rheumatoid arthritis with seropositivity, age and menopausal status as significant risk factors.

  17. Effects of salinity and the extent of water on supercritical CO2-induced phlogopite dissolution and secondary mineral formation.

    PubMed

    Shao, Hongbo; Ray, Jessica R; Jun, Young-Shin

    2011-02-15

    To ensure the viability of geologic CO2 sequestration (GCS), we need a holistic understanding of reactions at supercritical CO2 (scCO2)-saline water-rock interfaces and the environmental factors affecting these interactions. This research investigated the effects of salinity and the extent of water on the dissolution and surface morphological changes of phlogopite [KMg2.87Si3.07Al1.23O10(F,OH)2], a model clay mineral in potential GCS sites. Salinity enhanced the dissolution of phlogopite and affected the location, shape, size, and phase of secondary minerals. In low salinity solutions, nanoscale particles of secondary minerals formed much faster, and there were more nanoparticles than in high salinity solutions. The effect of water extent was investigated by comparing scCO2-H2O(g)-phlogopite and scCO2-H2O(l)-phlogopite interactions. Experimental results suggested that the presence of a thin water film adsorbed on the phlogopite surface caused the formation of dissolution pits and a surface coating of secondary mineral phases that could change the physical properties of rocks. These results provide new information for understanding reactions at scCO2-saline water-rock interfaces in deep saline aquifers and will help design secure and environmentally sustainable CO2 sequestration projects.

  18. Mineralizing urban net-zero water treatment: Field experience for energy-positive water management.

    PubMed

    Wu, Tingting; Englehardt, James D

    2016-12-01

    An urban net-zero water treatment system, designed for energy-positive water management, 100% recycle of comingled black/grey water to drinking water standards, and mineralization of hormones and other organics, without production of concentrate, was constructed and operated for two years, serving an occupied four-bedroom, four-bath university residence hall apartment. The system comprised septic tank, denitrifying membrane bioreactor (MBR), iron-mediated aeration (IMA) reactor, vacuum ultrafilter, and peroxone or UV/H 2 O 2 advanced oxidation, with 14% rainwater make-up and concomitant discharge of 14% of treated water (ultimately for reuse in irrigation). Chemical oxygen demand was reduced to 12.9 ± 3.7 mg/L by MBR and further decreased to below the detection limit (<0.7 mg/L) by IMA and advanced oxidation treatment. The process produced a mineral water meeting 115 of 115 Florida drinking water standards that, after 10 months of recycle operation with ∼14% rainwater make-up, had a total dissolved solids of ∼500 mg/L, pH 7.8 ± 0.4, turbidity 0.12 ± 0.06 NTU, and NO 3 -N concentration 3.0 ± 1.0 mg/L. None of 97 hormones, personal care products, and pharmaceuticals analyzed were detected in the product water. For a typical single-home system with full occupancy, sludge pumping is projected on a 12-24 month cycle. Operational aspects, including disinfection requirements, pH evolution through the process, mineral control, advanced oxidation by-products, and applicability of point-of-use filters, are discussed. A distributed, peroxone-based NZW management system is projected to save more energy than is consumed in treatment, due largely to retention of wastewater thermal energy. Recommendations regarding design and operation are offered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Enthalpy of formation of anisole: implications for the controversy on the O-H bond dissociation enthalpy in phenol.

    PubMed

    Simões, Ricardo G; Agapito, Filipe; Diogo, Hermínio P; da Piedade, Manuel E Minas

    2014-11-20

    Significant discrepancies in the literature data for the enthalpy of formation of gaseous anisole, ΔfHmo(PhOCH3, g), have fueled an ongoing controversy regarding the most reliable enthalpy of formation of the phenoxy radical and of the gas phase O-H bond dissociation enthalpy, DHo(PhO-H), in phenol. In the present work ΔfHmo(PhOCH3, g) was reassessed using a combination of calorimetric determinations and high-level (W2-F12) ab initio calculations. Static-bomb combustion calorimetry led to the standard molar enthalpy of formation of liquid anisole at 298.15 K, ΔfHmo(PhOCH3, l) = −(117.1 ± 1.4) kJ·mol(-1). The corresponding enthalpy of vaporization was obtained as, ΔvapHmo(PhOCH3) = 46.41 ± 0.26 kJ·mol(-1), by Calvet-drop microcalorimetry. These results give ΔfHmo(PhOCH3, g) = −(70.7 ± 1.4) kJ·mol(-1), in excellent agreement with ΔfHmo(PhOCH3, g) = −(70.8 ± 3.2) kJ·mol(-1), obtained from the W2-F12 calculations. The ΔfHmo(PhOCH3, g) here recommended leads to ΔfHmo(PhO•, g) = 55.5 ± 2.4 kJ·mol(-)1 and DH°(PhO-H) = 368.1 ± 2.6 kJ·mol(-1).

  20. Constant Enthalpy Change Value during Pyrophosphate Hydrolysis within the Physiological Limits of NaCl*

    PubMed Central

    Wakai, Satoshi; Kidokoro, Shun-ichi; Masaki, Kazuo; Nakasone, Kaoru; Sambongi, Yoshihiro

    2013-01-01

    A decrease in water activity was thought to result in smaller enthalpy change values during PPi hydrolysis, indicating the importance of solvation for the reaction. However, the physiological significance of this phenomenon is unknown. Here, we combined biochemistry and calorimetry to solve this problem using NaCl, a physiologically occurring water activity-reducing reagent. The pyrophosphatase activities of extremely halophilic Haloarcula japonica, which can grow at ∼4 m NaCl, and non-halophilic Escherichia coli and Saccharomyces cerevisiae were maximal at 2.0 and 0.1 m NaCl, respectively. Thus, halophilic and non-halophilic pyrophosphatases exhibit distinct maximal activities at different NaCl concentration ranges. Upon calorimetry, the same exothermic enthalpy change of −35 kJ/mol was obtained for the halophile and non-halophiles at 1.5–4.0 and 0.1–2.0 m NaCl, respectively. These results show that solvation changes caused by up to 4.0 m NaCl (water activity of ∼0.84) do not affect the enthalpy change in PPi hydrolysis. It has been postulated that PPi is an ATP analog, having a so-called high energy phosphate bond, and that the hydrolysis of both compounds is enthalpically driven. Therefore, our results indicate that the hydrolysis of high energy phosphate compounds, which are responsible for biological energy conversion, is enthalpically driven within the physiological limits of NaCl. PMID:23965994

  1. The thermochemistry of 2,4-pentanedione revisited: observance of a nonzero enthalpy of mixing between tautomers and its effects on enthalpies of formation.

    PubMed

    Temprado, Manuel; Roux, Maria Victoria; Umnahanant, Patamaporn; Zhao, Hui; Chickos, James S

    2005-06-30

    The enthalpies of formation of pure liquid and gas-phase (Z)-4-hydroxy-3-penten-2-one and 2,4-pentanedione are examined in the light of some more recent NMR studies on the enthalpy differences between gas-phase enthalpies of the two tautomers. Correlation gas chromatography experiments are used to evaluate the vaporization enthalpies of the pure tautomers. Values of (51.2 +/- 2.2) and (50.8 +/- 0.6) kJ.mol(-1) are measured for pure 2,4-pentanedione and (Z)-4-hydroxy-3-penten-2-one, respectively. The value of (50.8 +/- 0.6) kJ.mol(-1) can be contrasted to a value of (43.2 +/- 0.2) kJ.mol(-1) calculated for pure (Z)-4-hydroxy-3-penten-2-one when the vaporization enthalpy is measured in a mixture of tautomers. The difference is attributed to an endothermic enthalpy of mixing that destabilizes the mixture relative to the pure components. Calculation of new enthalpies of formation for (Z)-4-hydroxy-3-penten-2-one and 2,4-pentanedione in both the gas, Delta(f)H degrees (m)(g) = (-378.2 +/- 1.2) and (-358.9 +/- 2.5) kJ.mol(-1), respectively, and liquid phases, Delta(f)H degrees (m)(l) = (-429.0 +/- 1.0) and (-410.1 +/- 1.2) kJ.mol(-1), respectively, results in enthalpy differences between the two tautomers both in the liquid and gas phases that are identical within experimental error, and in excellent agreement with recent gas-phase NMR studies.

  2. [Influence of mineral water on absorption of oral alendronate in rats].

    PubMed

    Akagi, Yuuki; Sakaue, Tomoyuki; Yoneyama, Eiji; Aoyama, Takao

    2011-01-01

    Alendronate, an oral bisphosphonate (e.g., Fosamax(®)), is effective in the treatment of osteoporosis, and the Fosamax(®) package insert advises that the bioavailability is reduced when taken with mineral water containing high levels of metal cations (Ca(2+), Mg(2+), etc.). However, standards regarding the water used when taking alendronate are unclear. In this study, the influence of mineral water on the absorption of oral alendronate was investigated based on urinary excretion of its unchanged form in rats. Alendronate was diluted in each water sample and administered orally (0.7 mg/kg) to male Wistar rats after 24-hour fast. Urine samples were collected until 24 h after dosing. Urine samples were alkalinized, and alendronate in urine was precipitated as a calcium salt, followed by loading on an anion exchange cartridge. Eluted alendronate was derivatized with 9-fluorenylmethoxycarbonyl (Fmoc) chloride and determined by HPLC with fluorescent detection. Cumulative urinary excretion recoveries of alendronate were calculated from the amounts of urinary excretion. Alendronate was rapidly excreted in the first 6 h, and similar elimination rate constants were seen (from 0.28 to 0.45 h(-1/2)) among the water samples. Cumulative urinary excretion recoveries with tap water, evian(®) and 100% deep ocean water were 0.98±0.17%, 0.80±0.18% and 1.01±0.16% (mean±S.E., n=4). Those with Contrex(®) (0.33±0.07%) were significantly lower when compared with ultrapure water (1.56±0.35%, p<0.01). These findings suggest that the absorption of alendronate decreases based on the calcium concentration of mineral water. In conclusion, mineral water containing high levels of calcium is not recommended when alendronate is taken.

  3. Low bone mineral density in ambulatory persons with cerebral palsy? A systematic review.

    PubMed

    Mus-Peters, Cindy T R; Huisstede, Bionka M A; Noten, Suzie; Hitters, Minou W M G C; van der Slot, Wilma M A; van den Berg-Emons, Rita J G

    2018-05-22

    Non-ambulatory persons with cerebral palsy are prone to low bone mineral density. In ambulatory persons with cerebral palsy, bone mineral density deficits are expected to be small or absent, but a consensus conclusion is lacking. In this systematic review bone mineral density in ambulatory persons with cerebral palsy (Gross Motor Function Classification Scales I-III) was studied. Medline, Embase, and Web of Science were searched. According to international guidelines, low bone mineral density was defined as Z-score ≤ -2.0. In addition, we focused on Z-score ≤ -1.0 because this may indicate a tendency towards low bone mineral density. We included 16 studies, comprising 465 patients aged 1-65 years. Moderate and conflicting evidence for low bone mineral density (Z-score ≤ -2.0) was found for several body parts (total proximal femur, total body, distal femur, lumbar spine) in children with Gross Motor Function Classification Scales II and III. We found no evidence for low bone mineral density in children with Gross Motor Function Classification Scale I or adults, although there was a tendency towards low bone mineral density (Z-score ≤ -1.0) for several body parts. Although more high-quality research is needed, results indicate that deficits in bone mineral density are not restricted to non-ambulatory people with cerebral palsy. Implications for Rehabilitation Although more high-quality research is needed, including adults and fracture risk assessment, the current study indicates that deficits in bone mineral density are not restricted to non-ambulatory people with CP. Health care professionals should be aware that optimal nutrition, supplements on indication, and an active lifestyle, preferably with weight-bearing activities, are important in ambulatory people with CP, also from a bone quality point-of-view. If indicated, medication and fall prevention training should be prescribed.

  4. [Fluoride content of bottled natural mineral waters in Spain and prevention of dental caries].

    PubMed

    Maraver, Francisco; Vitoria, Isidro; Almerich-Silla, José Manuel; Armijo, Francisco

    2015-01-01

    The aim of the study was to determine the concentration of fluoride in natural mineral waters marketed in Spain in order to prevent tooth decay without the risk of causing dental fluorosis Descriptive and cross-sectional study during 2012. Natural mineral waters marketed in Spain. Three bottles with different bottling dates of 109 natural mineral waters (97 Spanish and 12 imported brands). Determination of fluoride by ion chromatography Median fluoride concentrations of the natural mineral waters bottled in Spain was 0.22 (range 0.00-4.16; interquartile range:0.37). Most samples (61 brands, 62%) contained less than 0.3mg/L. There are 19 Spanish brands with more than 0.6 mg/L. The median level in imported brands was 0.35 (range 0.10-1.21; interquartile range: 0.23). Only 28 of the 109 brands examined (25.6%) specified the fluoride content on the label. Good correlation was observed between the concentrations indicated and those determined. Fluoride concentrations in natural mineral waters showed high variation. Given the growing consumption of natural mineral waters in Spain, this type of information is important to make proper use of fluoride in the primary prevention of dental caries. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  5. The Relation between Vaporization Enthalpies and Viscosities: Eyring's Theory Applied to Selected Ionic Liquids.

    PubMed

    Bonsa, Anne-Marie; Paschek, Dietmar; Zaitsau, Dzmitry H; Emel'yanenko, Vladimir N; Verevkin, Sergey P; Ludwig, Ralf

    2017-05-19

    Key properties for the use of ionic liquids as electrolytes in batteries are low viscosities, low vapor pressure and high vaporization enthalpies. Whereas the measurement of transport properties is well established, the determination of vaporization enthalpies of these extremely low volatile compounds is still a challenge. At a first glance both properties seem to describe different thermophysical phenomena. However, eighty years ago Eyring suggested a theory which related viscosities and vaporization enthalpies to each other. The model is based on Eyring's theory of absolute reaction rates. Recent attempts to apply Eyring's theory to ionic liquids failed. The motivation of our study is to show that Eyring's theory works, if the assumptions specific for ionic liquids are fulfilled. For that purpose we measured the viscosities of three well selected protic ionic liquids (PILs) at different temperatures. The temperature dependences of viscosities were approximated by the Vogel-Fulcher-Tamann (VFT) relation and extrapolated to the high-temperature regime up to 600 K. Then the VFT-data could be fitted to the Eyring-model. The values of vaporization enthalpies for the three selected PILs predicted by the Eyring model have been very close to the experimental values measured by well-established techniques. We conclude that the Eyring theory can be successfully applied to the chosen set of PILs, if the assumption that ionic pairs of the viscous flow in the liquid and the ionic pairs in the gas phase are similar is fulfilled. It was also noticed that proper transfer of energies can be only derived if the viscosities and the vaporization energies are known for temperatures close to the liquid-gas transition temperature. The idea to correlate easy measurable viscosities of ionic liquids with their vaporization enthalpies opens a new way for a reliable assessment of these thermodynamic properties for a broad range of ionic liquids. © 2017 Wiley-VCH Verlag GmbH & Co. KGa

  6. Active Thermochemical Tables: Sequential Bond Dissociation Enthalpies of Methane, Ethane, and Methanol and the Related Thermochemistry

    DOE PAGES

    Ruscic, Branko

    2015-03-31

    Active Thermochemical Tables (ATcT) thermochemistry for the sequential bond dissociations of methane, ethane, and methanol systems were obtained by analyzing and solving a very large thermochemical network (TN). Values for all possible C–H, C–C, C–O, and O–H bond dissociation enthalpies at 298.15 K (BDE 298) and bond dissociation energies at 0 K (D 0) are presented. The corresponding ATcT standard gas-phase enthalpies of formation of the resulting CH n, n = 4–0 species (methane, methyl, methylene, methylidyne, and carbon atom), C 2H n, n = 6–0 species (ethane, ethyl, ethylene, ethylidene, vinyl, ethylidyne, acetylene, vinylidene, ethynyl, and ethynylene), and COHmore » n, n = 4–0 species (methanol, hydroxymethyl, methoxy, formaldehyde, hydroxymethylene, formyl, isoformyl, and carbon monoxide) are also presented. The ATcT thermochemistry of carbon dioxide, water, hydroxyl, and carbon, oxygen, and hydrogen atoms is also included, together with the sequential BDEs of CO 2 and H 2O. The provenances of the ATcT enthalpies of formation, which are quite distributed and involve a large number of relevant determinations, are analyzed by variance decomposition and discussed in terms of principal contributions. The underlying reasons for periodic appearances of remarkably low and/or unusually high BDEs, alternating along the dissociation sequences, are analyzed and quantitatively rationalized. The present ATcT results are the most accurate thermochemical values currently available for these species.« less

  7. Effect of a high bicarbonate mineral water on fasting and postprandial lipemia in moderately hypercholesterolemic subjects: a pilot study.

    PubMed

    Zair, Yassine; Kasbi-Chadli, Fatima; Housez, Beatrice; Pichelin, Mathieu; Cazaubiel, Murielle; Raoux, François; Ouguerram, Khadija

    2013-07-18

    During postprandial state, TG concentration is increasing and HDL cholesterol decreasing, leading to a transitory pro-atherosclerotic profile. Previous studies have reported that bicarbonate water improve postprandial lipemia. The objective of this study was to analyze the effect of a strongly bicarbonated mineral water on lipoprotein levels during fasting and postprandial state. A controlled, randomised, double-blind cross-over design was conducted in 12 moderately hypercholesterolemic subjects after a daily ingestion of 1.25 L of mineral (SY) or low mineral water during eight weeks separated by a one week wash-out period. Blood samples were collected in first visit to the hospital (V1) before water consumption (referent or SY) and in a second visit (V2) after eight week water consumption period. The effect of the consumed water was studied in fasting and in postprandial state during ingestion of a meal and 0.5 L of water. Comparison of data between V1 and V2 after SY consumption showed a significant decrease in triglyceridemia (23%), VLDL TG (31%) and tendency to a decrease of VLDL cholesterol (p = 0.066) at fasting state. Whatever the consumed water during postprandial state, the measurement of total areas under curves did not show a significant difference. No difference was observed between SY and referent water consumption for measured parameters at fasting and postprandial state. When subjects consumed SY we showed a decrease of their basal TG and VLDLTG. The unexpected absence of effect of high mineralized water on postprandial lipemia, probably related to experimental conditions, is discussed in the discussion section.

  8. The Consumption of Bicarbonate-Rich Mineral Water Improves Glycemic Control

    PubMed Central

    Murakami, Shinnosuke; Goto, Yasuaki; Ito, Kyo; Hayasaka, Shinya; Kurihara, Shigeo; Soga, Tomoyoshi; Tomita, Masaru; Fukuda, Shinji

    2015-01-01

    Hot spring water and natural mineral water have been therapeutically used to prevent or improve various diseases. Specifically, consumption of bicarbonate-rich mineral water (BMW) has been reported to prevent or improve type 2 diabetes (T2D) in humans. However, the molecular mechanisms of the beneficial effects behind mineral water consumption remain unclear. To elucidate the molecular level effects of BMW consumption on glycemic control, blood metabolome analysis and fecal microbiome analysis were applied to the BMW consumption test. During the study, 19 healthy volunteers drank 500 mL of commercially available tap water (TW) or BMW daily. TW consumption periods and BMW consumption periods lasted for a week each and this cycle was repeated twice. Biochemical tests indicated that serum glycoalbumin levels, one of the indexes of glycemic controls, decreased significantly after BMW consumption. Metabolome analysis of blood samples revealed that 19 metabolites including glycolysis-related metabolites and 3 amino acids were significantly different between TW and BMW consumption periods. Additionally, microbiome analysis demonstrated that composition of lean-inducible bacteria was increased after BMW consumption. Our results suggested that consumption of BMW has the possible potential to prevent and/or improve T2D through the alterations of host metabolism and gut microbiota composition. PMID:26798400

  9. Testing the Prediction of Iron Alteration Minerals on Low Albedo Asteroids

    NASA Technical Reports Server (NTRS)

    Jarvis, K. S.; Vilas, Faith; Howell, E.; Kelley, M.; Cochran, A.

    1999-01-01

    Absorption features centered near 0.60 - 0.65 and 0.80 - 0.90 micron were identified in the spectra of three low-albedo main-belt (165, 368, 877) and two low-albedo outer-belt (225, 334) asteroids (Vilas et al., Icarus, v. 109,274,1994). The absorption features were attributed to charge transfer transitions in iron alteration minerals such as goethite, hematite, and jarosite, all products of aqueous alteration. Concurrently, Jarvis et al. (LPSC XXIV, 715, 1993) presented additional spectra of low-albedo asteroids that had absorption features centered near 0.60 - 0.65 micron without the longer wavelength feature. Since these two features in iron oxides originate from the same ground state, and the longer wavelength feature requires less energy to exist, the single shorter wavelength feature cannot be caused by the iron alteration minerals. In addition, spectra of minerals such as hematite and goethite show a rapid increase in reflectance beginning near 0.5 micron absent in the low-albedo asteroid spectra. The absence of this rise has been attributed to its suppresion from opaques in the surface material. Spectra on more than one night were available for only one of these five asteroids, 225 Henrietta, and showed good repeatability of the 0.65-micron feature. We have acquired additional spectra of all five asteroids in order to test the repeatability of the 0.65-micron feature, and the presence and repeatability of the features centered near 0.8 - 0.9 micron. We specifically will test the possibility that longer wavelength features could be caused by incomplete removal of telluric water. Asteroid 877 Walkure is a member of the Nysa-Hertha family, and will be compared to spectra of other members of that family. Data were acquired in 1996 and 1999 on the 2.1-m telescope with a facility cassegrain spectrograph, McDonald Observatory, Univ. Of Texas, and the 1.5-m telescope with facility cassegrain spectrograph at CTIO. This research is supported by the NASA Planetary

  10. Hydrogeochemical and stable isotopic investigations on CO2-rich mineral waters from Harghita Mts. (Eastern Carpathians, Romania)

    NASA Astrophysics Data System (ADS)

    Kis, Boglárka-Mercedesz; Baciu, Călin; Kármán, Krisztina; Kékedy-Nagy, Ladislau; Francesco, Italiano

    2013-04-01

    There is a worldwide interest on geothermal, mineral and groundwater as a resource for energy, drinking water supply and therapeutic needs. The increasing trend in replacing tap water with commercial bottled mineral water for drinking purposes has become an economic, hydrogeologic and medical concern in the last decades. Several investigations have been carried out worldwide on different topics related to geothermal and mineral waters, dealing with mineral water quality assessment, origin of geothermal and mineral waters, geochemical processes that influence water chemistry and water-rock interaction In Romania, the Călimani-Gurghiu-Harghita Neogene to Quaternary volcanic chain (Eastern Carpathians) is one of the most important areas from the point of view of CO2-rich mineral waters. These mineral water springs occur within other post-volcanic phenomena like dry CO2 emissions, moffettes, bubbling pools, H2S gas emissions etc. Mineral waters from this area are used for bottling, local spas and drinking purposes for local people. The number of springs, around 2000 according to literature data, shows that there is still a significant unexploited potential for good quality drinking water in this area. Within the youngest segment of the volcanic chain, the Harghita Mts., its volcaniclastic aprons and its boundary with the Transylvanian Basin, we have carried out an investigation on 23 CO2-rich mineral water springs from a hydrogeochemical and stable isotopic point of view. The mineral waters are Ca-Mg-HCO3 to Na-Cl type. Sometimes mixing between the two types can be observed. We have detected a great influence of water-rock interaction on the stable isotopic composition of the mineral waters, shown by isotopic shifts to the heavier oxygen isotope, mixing processes between shallow and deeper aquifers and local thermal anomalies. Acknowledgements: The present work was financially supported by the Romanian National Research Council, Project PN-II-ID-PCE-2011-3-0537 and by

  11. Natural and mining-related sources of dissolved minerals during low flow in the Upper Animas River Basin, southwestern Colorado

    USGS Publications Warehouse

    Wright, Winfield G.

    1997-01-01

    As part of the Clean Water Act of 1972 (Public Law 92-500), all States are required to establish water-quality standards for every river basin in the State. During 1994, the Colorado Department of Public Health and Environment proposed to the Colorado Water Quality Control Commission (CWQCC) an aquatic-life standard of 225 µg/L (micrograms per liter) for the dissolved-zinc concentration in the Animas River downstream from Silverton (fig.1). The CWQCC delayed implementation of this water-quality standard until further information was collected and a plan for the cleanup of abandoned mines was developed. Dissolved-zinc concentrations in this section of the river ranged from about 270 µg/L during high flow, when rainfall and snowmelt runoff dilute the dissolved minerals in the river (U.S. Geological Survey, 1996, p. 431), to 960 µg/L (Colorado Department of Public Health and Environment, written commun., 1996) during low flow (such as late summer and middle winter when natural springs and drainage from mines are the main sources for the streams). Mining sites in the basin were developed between about 1872 and the 1940's, with only a few mines operated until the early 1990's. For local governments, mining sites represent part of the Nation's heritage, tourists are attracted to the historic mining sites, and governments are obligated to protect the historic mining sites according to the National Historic Preservation Act (Public Law 89-665). In the context of this fact sheet, the term "natural sources of dissolved minerals" refers to springs and streams where no effect from mining were determined. "Mining-related sources of dissolved minerals" are assumed to be: (1 ) Water draining from mines , and (2) water seeping from mine-waste dump pile where the waste piles were saturated by water draining from mines. Although rainfall and snowmelt runoff from mine-waste piles might affect water quality in streams, work described in this fact sheet was done during low

  12. [Effect of Seasonal Temperature Increasing on Nitrogen Mineralization in Soil of the Water Level Fluctuating Zone of Three Gorge Tributary During the Dry Period].

    PubMed

    Lin, Jun-jie; Zhang, Shuai; Liu, Dan; Zhou, Bin; Xiao, Xiao-jun; Ma, Hui-yan; Yu, Zhi-guo

    2016-02-15

    To reveal the effect of seasonal temperature increasing on nitrogen mineralization in soil of the water level fluctuating soil zone of three gorge reservoir areas in the Yangtze river tributary during the dry period, surface soils were collected from the water level fluctuating zone of Pengxi river crossing two hydrological sections, i.e., upstream and downstream and three water level altitudes, 155 m (low), 165 m (middle) and 175 m (high). We incubated the soil at 25 degrees C and 35 degrees C to determine the transformation rates of nitrogen in soil of Pengxi river basin during the dry period. The result showed that TN and NO3- -N contents in the soil of upstream section and higher (175 m) altitude of water level were higher than those in downstream and low (165 m) altitude of water level, whereas the pattern for NH4+ -N was different, with higher NH4+ -N contents in downstream and low water level. The inorganic nitrogen was dominated by NO3- -N, which accounted for up to 57.4%-84.7% of inorganic nitrogen. Generally, soil ammoniation, nitration and net N mineralization increased with the rising water level altitude and stream sections (P < 0.05). In summary, nitration and net N mineralization significantly increased with increasing temperature, (P < 0.05), while ammoniation showed no difference (P > 0.05).

  13. Free-flight measurement technique in the free-piston high-enthalpy shock tunnel.

    PubMed

    Tanno, H; Komuro, T; Sato, K; Fujita, K; Laurence, S J

    2014-04-01

    A novel multi-component force-measurement technique has been developed and implemented at the impulse facility JAXA-HIEST, in which the test model is completely unrestrained during the test and thus experiences free-flight conditions for a period on the order of milliseconds. Advantages over conventional free-flight techniques include the complete absence of aerodynamic interference from a model support system and less variation in model position and attitude during the test itself. A miniature on-board data recorder, which was a key technology for this technique, was also developed in order to acquire and store the measured data. The technique was demonstrated in a HIEST wind-tunnel test campaign in which three-component aerodynamic force measurement was performed on a blunted cone of length 316 mm, total mass 19.75 kg, and moment of inertia 0.152 kgm(2). During the test campaign, axial force, normal forces, and pitching moment coefficients were obtained at angles of attack from 14° to 32° under two conditions: H0 = 4 MJ/kg, P0 = 14 MPa; and H0 = 16 MJ/kg, P0 = 16 MPa. For the first, low-enthalpy condition, the test flow was considered a perfect gas; measurements were thus directly compared with those obtained in a conventional blow-down wind tunnel (JAXA-HWT2) to evaluate the accuracy of the technique. The second test condition was a high-enthalpy condition in which 85% of the oxygen molecules were expected to be dissociated; high-temperature real-gas effects were therefore evaluated by comparison with results obtained in perfect-gas conditions. The precision of the present measurements was evaluated through an uncertainty analysis, which showed the aerodynamic coefficients in the HIEST low enthalpy test agreeing well with those of JAXA-HWT2. The pitching-moment coefficient, however, showed significant differences between low- and high-enthalpy tests. These differences are thought to result from high-temperature real-gas effects.

  14. Free-flight measurement technique in the free-piston high-enthalpy shock tunnel

    NASA Astrophysics Data System (ADS)

    Tanno, H.; Komuro, T.; Sato, K.; Fujita, K.; Laurence, S. J.

    2014-04-01

    A novel multi-component force-measurement technique has been developed and implemented at the impulse facility JAXA-HIEST, in which the test model is completely unrestrained during the test and thus experiences free-flight conditions for a period on the order of milliseconds. Advantages over conventional free-flight techniques include the complete absence of aerodynamic interference from a model support system and less variation in model position and attitude during the test itself. A miniature on-board data recorder, which was a key technology for this technique, was also developed in order to acquire and store the measured data. The technique was demonstrated in a HIEST wind-tunnel test campaign in which three-component aerodynamic force measurement was performed on a blunted cone of length 316 mm, total mass 19.75 kg, and moment of inertia 0.152 kgm2. During the test campaign, axial force, normal forces, and pitching moment coefficients were obtained at angles of attack from 14° to 32° under two conditions: H0 = 4 MJ/kg, P0 = 14 MPa; and H0 = 16 MJ/kg, P0 = 16 MPa. For the first, low-enthalpy condition, the test flow was considered a perfect gas; measurements were thus directly compared with those obtained in a conventional blow-down wind tunnel (JAXA-HWT2) to evaluate the accuracy of the technique. The second test condition was a high-enthalpy condition in which 85% of the oxygen molecules were expected to be dissociated; high-temperature real-gas effects were therefore evaluated by comparison with results obtained in perfect-gas conditions. The precision of the present measurements was evaluated through an uncertainty analysis, which showed the aerodynamic coefficients in the HIEST low enthalpy test agreeing well with those of JAXA-HWT2. The pitching-moment coefficient, however, showed significant differences between low- and high-enthalpy tests. These differences are thought to result from high-temperature real-gas effects.

  15. Erosion of aluminum 6061-T6 under cavitation attack in mineral oil and water

    NASA Technical Reports Server (NTRS)

    Rao, B. C. S.; Buckley, D. H.

    1985-01-01

    Studies of the erosion of aluminum 6061-T6 under cavitation attack in distilled water, ordinary tap water and a viscous mineral oil are presented. The mean depth of penetration for the mineral oil was about 40 percent of that for water at the end of a 40 min test. The mean depth of penetration and its rate did not differ significantly for distilled and tap water. The mean depth of penetration rate for both distilled and tap water increased to a maximum and then decreased with test duration, while that for mineral oil had a maximum during the initial period. The ratio h/2a of the pit depth h to the pit diameter 2a varied from 0.04 to 0.13 in water and from 0.06 to 0.20 in mineral oil. Scanning electron microscopy indicates that the pits are initially formed over the grain boundaries and precipitates while the surface grains are deformed under cavitation attack.

  16. Validation of the enthalpy method by means of analytical solution

    NASA Astrophysics Data System (ADS)

    Kleiner, Thomas; Rückamp, Martin; Bondzio, Johannes; Humbert, Angelika

    2014-05-01

    Numerical simulations moved in the recent year(s) from describing the cold-temperate transition surface (CTS) towards an enthalpy description, which allows avoiding incorporating a singular surface inside the model (Aschwanden et al., 2012). In Enthalpy methods the CTS is represented as a level set of the enthalpy state variable. This method has several numerical and practical advantages (e.g. representation of the full energy by one scalar field, no restriction to topology and shape of the CTS). The proposed method is rather new in glaciology and to our knowledge not verified and validated against analytical solutions. Unfortunately we are still lacking analytical solutions for sufficiently complex thermo-mechanically coupled polythermal ice flow. However, we present two experiments to test the implementation of the enthalpy equation and corresponding boundary conditions. The first experiment tests particularly the functionality of the boundary condition scheme and the corresponding basal melt rate calculation. Dependent on the different thermal situations that occur at the base, the numerical code may have to switch to another boundary type (from Neuman to Dirichlet or vice versa). The main idea of this set-up is to test the reversibility during transients. A former cold ice body that run through a warmer period with an associated built up of a liquid water layer at the base must be able to return to its initial steady state. Since we impose several assumptions on the experiment design analytical solutions can be formulated for different quantities during distinct stages of the simulation. The second experiment tests the positioning of the internal CTS in a parallel-sided polythermal slab. We compare our simulation results to the analytical solution proposed by Greve and Blatter (2009). Results from three different ice flow-models (COMIce, ISSM, TIMFD3) are presented.

  17. Stable mineral recrystallization in low temperature aqueous systems: A critical review

    NASA Astrophysics Data System (ADS)

    Gorski, Christopher A.; Fantle, Matthew S.

    2017-02-01

    Minerals may undergo recrystallization reactions in low temperature (<100 °C) aqueous systems, during which they exchange isotopes and trace elements with the dissolved reservoir without undergoing overt structural, bulk compositional, or morphological changes. These interfacial reactions, which are often referred to in the literature as "atom exchange" and herein as "stable mineral recrystallization", have important implications for the use of isotopic and elemental proxies to interpret past temperatures, oxidation states, and aqueous chemistries on Earth. The reactions are also significant for modern environments, including engineered systems, as they imply that mineral lattices may be substantially more open to exchanging toxic elements and radionuclides with coexisting solutions than previously thought. To date, observations of stable mineral recrystallization are distributed among several disciplines, and no work has attempted to review their findings comprehensively. Accordingly, this review article presents laboratory evidence for stable mineral recrystallization, describes data collection and interpretation strategies, summarizes similar recrystallization systematics observed in multiple studies, explores the potential occurrence of stable mineral recrystallization in natural systems, and discusses possible mechanisms by which stable mineral recrystallization occurs. The review focuses primarily on carbonates, sulfates, and iron oxides because these minerals have been studied most extensively to date. The review concludes by presenting key questions that should be addressed in this field to further understand and account for stable mineral recrystallization in natural and engineered aqueous systems at low temperatures.

  18. Microbial mineral illization of montmorillonite in low-permeability oil reservoirs for microbial enhanced oil recovery.

    PubMed

    Cui, Kai; Sun, Shanshan; Xiao, Meng; Liu, Tongjing; Xu, Quanshu; Dong, Honghong; Wang, Di; Gong, Yejing; Sha, Te; Hou, Jirui; Zhang, Zhongzhi; Fu, Pengcheng

    2018-05-11

    Microbial mineral illization has been investigated for its role in the extraction and recovery of metals from ores. Here we report our application of mineral bioillization for the microbial enhanced oil recovery in low-permeability oil reservoirs. It aimed to reveal the etching mechanism of the four Fe (III)-reducing microbial strains under anaerobic growth conditions on the Ca-montmorillonite. The mineralogical characterization of the Ca-montmorillonite was performed by Fourier transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy and energy dispersive spectrometer. Results showed that the microbial strains could efficiently reduce Fe (III) at an optimal rate of 71 %, and alter the crystal lattice structure of the lamella to promote the interlayer cation exchange, and to efficiently inhibit the Ca-montmorillonite swelling at an inhibitory rate of 48.9 %. Importance Microbial mineral illization is ubiquitous in the natural environment. Microbes in low-permeability reservoirs are able to enable the alteration of the structure and phase of the Fe-poor minerals by reducing Fe (III) and inhibiting clay swelling which is still poorly studied. This study aimed to reveal the interaction mechanism between Fe (III)-reducing bacterial strains and Ca-montmorillonite under anaerobic atmosphere, and to investigate the extent and rates of Fe (III) reduction and phase changes with their activities. Application of Fe (III)-reducing bacteria will provide a new way to inhibit clay swelling, to elevate reservoir permeability, and to reduce pore throat resistance after water flooding for enhanced oil recovery in low-permeability reservoirs. Copyright © 2018 American Society for Microbiology.

  19. Improved methods for the enumeration of heterotrophic bacteria in bottled mineral waters.

    PubMed

    Ramalho, R; Cunha, J; Teixeira, P; Gibbs, P A

    2001-03-01

    At this time the European Union regulations require that the heterotrophic plate counts (HPC) of mineral waters be assessed at two recovery temperatures: 22 degrees C for 72 h and 37 degrees C for 24 h. This procedure is time consuming and expensive. Development of new rapid methods for microbiological assessment of the microbial flora in the bottled water is an industry-driven need. The objectives of this work were to develop a method for the HPC that utilises only one recovery temperature and one incubation period and evaluate the use of, the LIVE/DEAD(R) BacLight Bacterial Viability Kit, 5-cyano-2,3-ditotyl tetrazolium chloride (CTC) and impedance methods to enumerate viable bacteria in bottled mineral water. Results showed that incubation at 30 degrees C could be used instead of incubation at 22 degrees C and 37 degrees C. Good correlation exists between counts at 30 degrees C and counts at 22 degrees C (r>0.90) and all the pathogens important in mineral water analyses grow similarly at 30 degrees C and 37 degrees C during 24 h. It was demonstrated that impedance methods might be useful to the mineral water industry as a rapid indicator of microbiological quality of the water. Results obtained with BacLight and CTC were similar to those obtained with plate counts.

  20. Increase of stagnation pressure and enthalpy in shock tunnels

    NASA Technical Reports Server (NTRS)

    Bogdanoff, David W.; Cambier, Jean-Luc

    1992-01-01

    High stagnation pressures and enthalpies are required for the testing of aerospace vehicles such as aerospace planes, aeroassist vehicles, and reentry vehicles. Among the most useful ground test facilities for performing such tests are shock tunnels. With a given driver gas condition, the enthalpy and pressure in the driven tube nozzle reservoir condition can be varied by changing the driven tube geometry and initial gas fill pressure. Reducing the driven tube diameter yields only very modest increases in reservoir pressure and enthalpy. Reducing the driven tube initial gas fill pressure can increase the reservoir enthalpy significantly, but at the cost of reduced reservoir pressure and useful test time. A new technique, the insertion of a converging section in the driven tube is found to produce substantial increases in both reservoir pressure and enthalpy. Using a one-dimensional inviscid full kinetics code, a number of different locations and shapes for the converging driven tube section were studied and the best cases found. For these best cases, for driven tube diameter reductions of factors of 2 and 3, the reservoir pressure can be increased by factors of 2.1 and 3.2, respectively and the enthalpy can be increased by factors of 1.5 and 2.1, respectively.

  1. Links between climate change, water-table depth, and water chemistry in a mineralized mountain watershed

    USGS Publications Warehouse

    Manning, Andrew H.; Verplanck, Philip L.; Caine, Jonathan S.; Todd, Andrew S.

    2013-01-01

    Recent studies suggest that climate change is causing rising solute concentrations in mountain lakes and streams. These changes may be more pronounced in mineralized watersheds due to the sensitivity of sulfide weathering to changes in subsurface oxygen transport. Specific causal mechanisms linking climate change and accelerated weathering rates have been proposed, but in general remain entirely hypothetical. For mineralized watersheds, a favored hypothesis is that falling water tables caused by declining recharge rates allow an increasing volume of sulfide-bearing rock to become exposed to air, thus oxygen. Here, we test the hypothesis that falling water tables are the primary cause of an increase in metals and SO4 (100-400%) observed since 1980 in the Upper Snake River (USR), Colorado. The USR drains an alpine watershed geologically and climatologically representative of many others in mineralized areas of the western U.S. Hydrologic and chemical data collected from 2005 to 2011 in a deep monitoring well (WP1) at the top of the USR watershed are utilized. During this period, both water table depths and groundwater SO4 concentrations have generally increased in the well. A numerical model was constructed using TOUGHREACT that simulates pyrite oxidation near WP1, including groundwater flow and oxygen transport in both saturated and unsaturated zones. The modeling suggests that a falling water table could produce an increase in metals and SO4 of a magnitude similar to that observed in the USR (up to 300%). Future water table declines may produce limited increases in sulfide weathering high in the watershed because of the water table dropping below the depth of oxygen penetration, but may continue to enhance sulfide weathering lower in the watershed where water tables are shallower. Advective air (oxygen) transport in the unsaturated zone caused by seasonally variable recharge and associated water table fluctuations was found to have little influence on pyrite

  2. Ingestion of a natural mineral-rich water in an animal model of metabolic syndrome: effects in insulin signalling and endoplasmic reticulum stress.

    PubMed

    Pereira, Cidália D; Passos, Emanuel; Severo, Milton; Vitó, Isabel; Wen, Xiaogang; Carneiro, Fátima; Gomes, Pedro; Monteiro, Rosário; Martins, Maria J

    2016-05-01

    High-fructose and/or low-mineral diets are relevant in metabolic syndrome (MS) development. Insulin resistance (IR) represents a central mechanism in MS development. Glucocorticoid signalling dysfunction and endoplasmic reticulum (ER) and oxidative stresses strongly contribute to IR and associate with MS. We have described that natural mineral-rich water ingestion delays fructose-induced MS development, modulates fructose effects on the redox state and glucocorticoid signalling and increases sirtuin 1 expression. Here, we investigated mineral-rich water ingestion effects on insulin signalling and ER homeostasis of fructose-fed rats. Adult male Sprague-Dawley rats had free access to standard-chow diet and different drinking solutions (8 weeks): tap water (CONT), 10%-fructose/tap water (FRUCT) or 10%-fructose/mineral-rich water (FRUCTMIN). Hepatic and adipose (visceral, VAT) insulin signalling and hepatic ER homeostasis (Western blot or PCR) as well as hepatic lipid accumulation were evaluated. Hepatic p-IRS1Ser307/IRS1 (tendency), p-IRS1Ser307, total JNK and (activated IRE1α)/(activated JNK) decreased with fructose ingestion, while p-JNK tended to increase; mineral-rich water ingestion, totally or partially, reverted all these effects. Total PERK, p-eIF2α (tendency) and total IRS1 (tendency) decreased in both fructose-fed groups. p-ERK/ERK and total IRE1α increasing tendencies in FRUCT became significant in FRUCTMIN (similar pattern for lipid area). Additionally, unspliced-XBP1 increased with mineral-rich water. In VAT, total ERK fructose-induced increase was partially prevented in FRUCTMIN. Mineral-rich water modulation of fructose-induced effects on insulin signalling and ER homeostasis matches the better metabolic profile previously reported. Increased p-ERK/ERK, adding to decreased IRE1α activation, and increased unspliced-XBP1 and lipid area may protect against oxidative stress and IR development in FRUCTMIN.

  3. Experimental formation enthalpies for intermetallic phases and other inorganic compounds

    PubMed Central

    Kim, George; Meschel, S. V.; Nash, Philip; Chen, Wei

    2017-01-01

    The standard enthalpy of formation of a compound is the energy associated with the reaction to form the compound from its component elements. The standard enthalpy of formation is a fundamental thermodynamic property that determines its phase stability, which can be coupled with other thermodynamic data to calculate phase diagrams. Calorimetry provides the only direct method by which the standard enthalpy of formation is experimentally measured. However, the measurement is often a time and energy intensive process. We present a dataset of enthalpies of formation measured by high-temperature calorimetry. The phases measured in this dataset include intermetallic compounds with transition metal and rare-earth elements, metal borides, metal carbides, and metallic silicides. These measurements were collected from over 50 years of calorimetric experiments. The dataset contains 1,276 entries on experimental enthalpy of formation values and structural information. Most of the entries are for binary compounds but ternary and quaternary compounds are being added as they become available. The dataset also contains predictions of enthalpy of formation from first-principles calculations for comparison. PMID:29064466

  4. The Relationships between Two Different Drinking Water Fluoride Levels, Dental Fluorosis and Bone Mineral Density of Children

    PubMed Central

    Grobler, S.R; Louw, A.J; Chikte, U.M.E; Rossouw, R.J; van W Kotze, T.J.

    2009-01-01

    This field study included the whole population of children aged 10–15 years (77 from a 0.19 mg/L F area; 89 from a 3.00 mg/L F area), with similar nutritional, dietary habits and similar ethnic and socioeconomic status. The fluoride concentration in the drinking water, the bone mineral content, the bone density and the degree of dental fluorosis were determined. The left radius was measured for bone width, bone mineral content, and bone mineral density. The mean fluorosis score was 1.3 in the low fluoride area and 3,6 in the high fluoride area. More than half the children in the low fluoride area had no fluorosis (scores 0 and 1) while only 5% in the high fluoride area had none. Severe fluorosis (30%) was only observed in the high fluoride area. The Wilcoxon Rank Sum Test indicated that fluorosis levels differed significantly (p < 0.05) between the two areas. No relationships were found between dental fluorosis and bone width or between fluorosis and bone mineral density in the two areas (Spearment Rank correlations). A significant increase in bone width was found with age but no differences amongst and boys and girls. A significant positive correlation was found in the high fluoride area between bone mineral density over age. In the 12-13 and 13-14 year age groups in the high fluoride area, girls had higher bone mineral densities. However, a significant negative correlation (p<0.02) was found for the low fluoride area (0.19 mg/L F) over age. PMID:19444344

  5. Accounting for apparent deviations between calorimetric and van't Hoff enthalpies.

    PubMed

    Kantonen, Samuel A; Henriksen, Niel M; Gilson, Michael K

    2018-03-01

    In theory, binding enthalpies directly obtained from calorimetry (such as ITC) and the temperature dependence of the binding free energy (van't Hoff method) should agree. However, previous studies have often found them to be discrepant. Experimental binding enthalpies (both calorimetric and van't Hoff) are obtained for two host-guest pairs using ITC, and the discrepancy between the two enthalpies is examined. Modeling of artificial ITC data is also used to examine how different sources of error propagate to both types of binding enthalpies. For the host-guest pairs examined here, good agreement, to within about 0.4kcal/mol, is obtained between the two enthalpies. Additionally, using artificial data, we find that different sources of error propagate to either enthalpy uniquely, with concentration error and heat error propagating primarily to calorimetric and van't Hoff enthalpies, respectively. With modern calorimeters, good agreement between van't Hoff and calorimetric enthalpies should be achievable, barring issues due to non-ideality or unanticipated measurement pathologies. Indeed, disagreement between the two can serve as a flag for error-prone datasets. A review of the underlying theory supports the expectation that these two quantities should be in agreement. We address and arguably resolve long-standing questions regarding the relationship between calorimetric and van't Hoff enthalpies. In addition, we show that comparison of these two quantities can be used as an internal consistency check of a calorimetry study. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Low-Temperature Heat Capacities and Standard Molar Enthalpy of Formation of Potassium Benzoate C7H5O2K(s)

    NASA Astrophysics Data System (ADS)

    Yang, Wei-Wei; di, You-Ying; Yin, Zhen-Fen; Kong, Yu-Xia; Tan, Zhi-Cheng

    2009-04-01

    Potassium benzoate C7H5O2K (CAS Registry No. 582-25-2) was synthesized by the method of liquid phase reaction. Chemical and elemental analyses, FTIR, and X-ray powder diffraction (XRD) techniques were applied to characterize the composition and structure of the compound. Low-temperature heat capacities of the compound were measured by a precision automated adiabatic calorimeter over the temperature range from 78 K to 398 K. A polynomial equation of the heat capacities as a function of temperature was fitted by the least-squares method. Smoothed heat capacities and thermodynamic functions of the compound were calculated based on the fitted polynomial. In accordance with Hess’s law, a reasonable thermochemical cycle was designed, and 100 mL of 1 mol · dm-3 NaOH solution was chosen as the calorimetric solvent. The standard molar enthalpies of dissolution for the reactants and products of the supposed reaction in the selected solvent were measured by an isoperibol solution-reaction calorimeter. Finally, the standard molar enthalpy of formation of the title compound C7H5O2K (s) was derived to be -(610.94 ± 0.77) kJ · mol-1.

  7. Thermodynamic analysis of the interaction of partially hydrophobic cationic polyelectrolytes with sodium halide salts in water

    NASA Astrophysics Data System (ADS)

    Bončina, Matjaž; Lukšič, Miha; Seručnik, Mojca; Vlachy, Vojko

    2014-05-01

    Isothermal titration calorimetry was used to determine the temperature and concentration dependence of the enthalpy of mixing of 3,3- and 6,6-ionene fluorides, bromides, and iodides with low molecular weight salts (NaF, NaCl, NaBr, and NaI) in water. The magnitudes of the enthalpies, measured in the temperature range from 273 to 318 K, depended on the number of methylene groups on the ionene polyion (hydrophobicity), and on the anion of the added salt (ion-specificity). All enthalpies of mixing of 3,3- and 6,6-ionene fluorides with low molecular weight salts (NaCl, NaBr, and NaI) were negative, which is in contrast to the predictions of standard theories of polyelectrolyte solutions. This fact was interpreted in the light of the ion-water short-range interactions that are not accounted for in those theories. In contrast, the enthalpies of mixing of 3,3- and 6,6-ionene bromides and iodides with NaF were positive, being in accord with theory. Using the calorimetric data, we performed a model thermodynamic analysis of the polyelectrolyte-salt mixing process to obtain changes in the apparent standard Gibbs free energy, enthalpy, entropy, and heat capacity relative to the pure ionene fluorides in water. The results prove that halide ions replace fluoride counterions with a strength increasing in the order chloride < bromide < iodide. The process is enthalpy governed, accompanied by a positive change in the heat capacity.

  8. Microorganisms in the deposits of cold carbon mineral waters of the Russian Far East and their habitats

    NASA Astrophysics Data System (ADS)

    Kalitina, E. G.; Kharitonova, N. A.; Kuzmina, T. V.; Chelnokov, G. A.

    2018-01-01

    Study of the chemical composition of carbon mineral waters has shown the prevalence of calcium, magnesium and sodium among the cations, sulfate, nitrate and chloride ions among the anions, and ferric iron, strontium and manganese in the microelement composition. Results of the microbiological studies have revealed that carbon mineral waters contain various microorganisms that can transform the physical and chemical composition of mineral waters by interfering with geochemical cycles. The sanitary and microbiological properties of carbon mineral waters have been evaluated thus proving that the waters of Medvezhii (Shmakovskoe deposit) are microbiologically clean.

  9. Aqueous geochemistry of low molecular weight hydrocarbons at elevated temperatures and pressures: constraints from mineral buffered laboratory experiments

    NASA Astrophysics Data System (ADS)

    Seewald, Jeffrey S.

    2001-05-01

    Organic matter, water, and minerals coexist at elevated temperatures and pressures in sedimentary basins and participate in a wide range of geochemical processes that includes the generation of oil and natural gas. A series of laboratory experiments were conducted at 300 to 350°C and 350 bars to examine chemical interactions involving low molecular weight aqueous hydrocarbons with water and Fe-bearing minerals under hydrothermal conditions. Mineral buffers composed of hematite-magnetite-pyrite, hematite-magnetite, and pyrite-pyrrhotite-magnetite were added to each experiment to fix the redox state of the fluid and the activity of reduced sulfur species. During each experiment the chemical system was externally modified by addition of ethene, ethane, propene, 1-butene, or n-heptane, and variations in the abundance of aqueous organic species were monitored as a function of time and temperature. Results of the experiments indicate that decomposition of aqueous n-alkanes proceeds through a series of oxidation and hydration reactions that sequentially produce alkenes, alcohols, ketones, and organic acids as reaction intermediaries. Organic acids subsequently undergo decarboxylation and/or oxidation reactions to form carbon dioxide and shorter chain saturated hydrocarbons. This alteration assemblage is compositionally distinct from that produced by thermal cracking under anhydrous conditions, indicating that the presence of water and minerals provide alternative reaction pathways for the decomposition of hydrocarbons. The rate of hydrocarbon oxidation decreases substantially under reducing conditions and in the absence of catalytically active aqueous sulfur species. These results represent compelling evidence that the stability of aqueous hydrocarbons at elevated temperatures in natural environments is not a simple function of time and temperature alone. Under the appropriate geochemical conditions, stepwise oxidation represents a mechanism for the decomposition of low

  10. Hydrogen and oxygen isotope exchange reactions between clay minerals and water

    USGS Publications Warehouse

    O'Neil, J.R.; Kharaka, Y.K.

    1976-01-01

    The extent of hydrogen and oxygen isotope exchange between clay minerals and water has been measured in the temperature range 100-350?? for bomb runs of up to almost 2 years. Hydrogen isotope exchange between water and the clays was demonstrable at 100??. Exchange rates were 3-5 times greater for montmorillonite than for kaolinite or illite and this is attributed to the presence of interlayer water in the montmorillonite structure. Negligible oxygen isotope exchange occurred at these low temperatures. The great disparity in D and O18 exchange rates observed in every experiment demonstrates that hydrogen isotope exchange occurred by a mechanism of proton exchange independent of the slower process of O18 exchange. At 350?? kaolinite reacted to form pyrophyllite and diaspore. This was accompanied by essentially complete D exchange but minor O18 exchange and implies that intact structural units in the pyrophyllite were inherited from the kaolinite precursor. ?? 1976.

  11. The calcium concentration of public drinking waters and bottled mineral waters in Spain and its contribution to satisfying nutritional needs.

    PubMed

    Vitoria, Isidro; Maraver, Francisco; Ferreira-Pêgo, Cíntia; Armijo, Francisco; Moreno Aznar, Luis; Salas-Salvadó, Jordi

    2014-07-01

    A sufficient intake of calcium enables correct bone mineralization. The bioavailability of calcium in water is similar to that in milk. To determine the concentration of calcium in public drinking water and bottled mineral water. We used ion chromatography to analyse the calcium concentrations of public drinking waters in a representative sample of 108 Spanish municipalities (21,290,707 people) and of 109 natural mineral waters sold in Spain, 97 of which were produced in Spain and 12 of which were imported. The average calcium concentration of public drinking waters was 38.96 ± 32.44 mg/L (range: 0.40- 159.68 mg/L). In 27 municipalities, the water contained 50-100 mg/L of calcium and in six municipalities it contained over 100 mg/L. The average calcium concentration of the 97 Spanish natural mineral water brands was 39.6 mg/L (range: 0.6-610.1 mg/L). Of these, 34 contained 50-100 mg/L of calcium and six contained over 100 mg/L. Of the 12 imported brands, 10 contained over 50 mg/L. Assuming water consumption is as recommended, water containing 50-100 mg/L of calcium provides 5.4-12.8% of the recommended intake of calcium for children aged one to thirteen, up to 13.6% for adolescents, 5.8-17.6% for adults, and up to 20.8% for lactating mothers. Water with 100-150 mg/L of calcium provides 10-31% of the recommended dietary allowance, depending on the age of the individual. Public drinking water and natural mineral water consumption in a third of Spanish cities can be considered an important complementary source of calcium. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  12. IMMOBILIZATION OF HEAVY METALS IN SOILS AND WATER BY A MANGANESE MINERAL

    EPA Science Inventory

    A synthesized Mn mineral used in study on adsorption of heavy metals from water has shown a great adsorption capability for Pb, Cu, Cd, Co, Ni and Zn on this mineral over a pH range from 2 to 8. The retention of Pb on this mineral was as high as 10% of its weight. Application of ...

  13. [The marketing evaluation of the consumers' preference as regards the use of medicinal and medicinal table mineral waters].

    PubMed

    Babaskin, D V; Babaskina, L I; Pavlova, A V

    2017-12-28

    The development of modern technologies in physiotherapy with the use of mineral waters, the expansion of the assortment of the medicinal and medicinal table waters as well as increasing the competitive advantages of domestic products require the more extensive marketing survey of the consumers' preferences in the market of mineral waters. The objective of the present study was the marketing evaluation of the consumers' preference in the segment of medicinal and medicinal table mineral waters in the city of Moscow. The survey involved 697 consumers of medicinal and medicinal table mineral waters. The sampling was carried out by the deterministic quota method. The field research was conducted by means of personal verbal interviews (32%) and the CATI to Web method (phone recruiting and on-line questioning) (68%) with the use of the structured questionnaire. Positioning was carried out making use of the two-dimensional schematic map and scoring assessment on an individual basis with calculation of integrated indicators. The marketing evaluation has demonstrated that the principal motive for purchasing mineral waters in more than 40% of respondents was the treatment and prevention of various diseases including disturbances in the urogenital system as well as digestive and respiratory disorders that appear to be the most frequent reasons for the consumption of mineral waters. The main factors that form the preferences of the consumers as regards the use of a concrete variety of mineral waters were elucidated. Of crucial importance for approximately 40% of the consumers (p<0.01) proved to be their health condition, the medical indications, and the available information about the therapeutic effectiveness of one or another type of mineral waters. Other factors were the quality of mineral water, its cost, the manufacturer and/or place of production, the attractiveness of the packaging, etc. The evaluation of the positioning of the mineral water consumers' preferences made

  14. Effect of sodium chloride- and sodium bicarbonate-rich mineral water on blood pressure and metabolic parameters in elderly normotensive individuals: a randomized double-blind crossover trial.

    PubMed

    Schorr, U; Distler, A; Sharma, A M

    1996-01-01

    To examine the effect of sodium chloride- and sodium bicarbonate-rich mineral water on blood pressure and parameters of glucose and lipid metabolism in elderly normotensive individuals. We examined 21 healthy men and women aged 60-72 years in a randomized, placebo-controlled, double-blind crossover trial. After reducing dietary salt intake to below 100 mmol/day, study participants were randomly assigned to drink 1.5 l daily of a sodium chloride-rich (sodium 84.5 mmol/l, chloride 63.7 mmol/l, bicarbonate 21.9 mmol/l), a sodium bicarbonate-rich (sodium 39.3 mmol/l, chloride 6.5 mmol/l, bicarbonate 48.8 mmol/l) and a low-sodium (placebo: sodium, chloride and bicarbonate < 0.02 mmol/l) mineral water for 4 weeks each in a three-phase crossover order. Each phase was separated by a 2-week washout period in which the study participants remained on a low-salt diet. Compliance was assessed by biweekly urinary electrolyte excretion and five study participants were excluded from analysis for failing to complete the trial or to fulfil the compliance criteria. Mean arterial blood pressure was significantly lower during the periods of consuming low-sodium -7.0 +/- 7.2 mmHg, P < 0.001) or sodium bicarbonate-rich (-5.7 +/- 6.4 mmHg, P < 0.05) water than at baseline. In contrast, blood pressure during the phase of drinking sodium chloride-rich water was identical to that at baseline. Ambulatory 24 h blood pressure, oral glucose tolerance and plasma lipids were not affected by the different regimens. Urinary calcium excretion was significantly reduced by drinking low-sodium or sodium bicarbonate-rich water but was unchanged under the sodium chloride-rich water. Consumption of sodium chloride-rich mineral water can abolish the blood pressure reduction induced by dietary salt restriction in elderly individuals. Sodium bicarbonate-rich mineral water in conjunction with a low-salt diet may have a beneficial effect on calcium homeostasis.

  15. Crystallographic controls on the frictional behavior of dry and water-saturated sheet structure minerals

    USGS Publications Warehouse

    Moore, Diane E.; Lockner, D.A.

    2004-01-01

    We compare the frictional strengths of 17 sheet structure mineral powders, measured under dry and water-saturated conditions, to identify the factors that cause many of them to be relatively weak. The dry coefficient of friction ?? ranges upward from 0.2 for graphite, leveling off at 0.8 for margarite, clintonite, gibbsite, kaolinite, and lizardite. The values of ?? (dry) correlate directly with calculated (001) interlayer bond strengths of the minerals. This correlation occurs because shear becomes localized along boundary and Riedel shears and the platy minerals in them rotate into alignment with the shear planes. For those gouges with ?? (dry) < 0.8, shear occurs by breaking the interlayer bonds to form new cleavage surfaces. Where ?? (dry) = 0.8, consistent with Byerlee's law, the interlayer bonds are sufficiently strong that other frictional processes dominate. The transition in dry friction mechanisms corresponds to calculated surface energies of 2-3 J/m2. Adding water causes ?? to decrease for every mineral tested except graphite. If the minerals are separated into groups with similar crystal structures, ?? (wet) increases with increasing interlayer bond strength within each group. This relationship also holds for the swelling clay montmorillonite, whose water-saturated strength is consistent with the strengths of nonswelling clays of similar crystal structure. Water in the saturated gouges forms thin, structured films between the plate surfaces. The polar water molecules are bonded to the plate surfaces in proportion to the mineral's surface energy, and ?? (wet) reflects the stresses required to shear through the water films. Copyright 2004 by the American Geophysical Union.

  16. Interaction between Bisphosphonates and Mineral Water: Study of Oral Risedronate Absorption in Rats.

    PubMed

    Itoh, Akihisa; Akagi, Yuuki; Shimomura, Hitoshi; Aoyama, Takao

    2016-01-01

    Bisphosphonates are antiosteoporotic agents prescribed for patients with osteoporosis. Drug package inserts for bisphosphonate supplements indicate that their bioavailability is reduced by high levels of metal cations (Ca(2+), Mg(2+), etc.). However, standards for these cations in water used for taking risedronate have not been defined. Here, we examined the effect of calcium and magnesium in mineral waters on the bioavailability of the third-generation bisphosphonate, risedronate, following oral administration in rats. As risedronate is unchanged and eliminated renally, risedronate absorption was estimated from the amount excreted in the urine. Risedronate was dissolved in mineral water samples and administered orally at 0.35 mg/kg. Urine samples were collected for 24 h after dosing. Risedronate was extracted from urine using ion-pair solid-phase cartridges and quantified by HPLC with UV detection (262 nm). Cumulative recovery of risedronate was calculated from the amount excreted in the urine. The 24-h recovery of risedronate from evian® (0.32±0.02% [mean±standard deviation (S.D.)], n=4) and Contrex(®) (0.22±0.05%) mineral waters was significantly lower than that from tap water (0.47±0.04%, p<0.01). Absorption of risedronate in calcium chloride and magnesium chloride aqueous solutions of the same hardness (822 mg/L) was 54% (0.27±0.04%) and 12% (0.51±0.08%) lower, respectively, compared with ultrapure water; suggesting that absorption of risedronate declines as the calcium concentration of mineral waters increases. Consumption of mineral waters containing high levels of calcium (80 mg/L or above), such as evian® and Contrex(®), is therefore not recommended when taking risedronate.

  17. Fluorite solubility equilibria in selected geothermal waters

    USGS Publications Warehouse

    Nordstrom, D. Kirk; Jenne, E.A.

    1977-01-01

    Calculation of chemical equilibria in 351 hot springs and surface waters from selected geothermal areas in the western United States indicate that the solubility of the mineral fluorite, CaF2, provides an equilibrium control on dissolved fluoride activity. Waters that are undersaturated have undergone dilution by non-thermal waters as shown by decreased conductivity and temperature values, and only 2% of the samples are supersaturated by more than the expected error. Calculations also demonstrate that simultaneous chemical equilibria between the thermal waters and calcite as well as fluorite minerals exist under a variety of conditions. Testing for fluorite solubility required a critical review of the thermodynamic data for fluorite. By applying multiple regression of a mathematical model to selected published data we have obtained revised estimates of the pK (10,96), ??Gof (-280.08 kcal/mole), ??Hof (-292.59 kcal/mole), S?? (16.39 cal/deg/mole) and CoP (16.16 cal/deg/mole) for CaF2 at 25??C and 1 atm. Association constants and reaction enthalpies for fluoride complexes with boron, calcium and iron are included in this review. The excellent agreement between the computer-based activity products and the revised pK suggests that the chemistry of geothermal waters may also be a guide to evaluating mineral solubility data where major discrepancies are evident. ?? 1977.

  18. Enthalpy of formation of Fe 3Al 2Si 3O 12 (almandine) by high temperature alkali borate solution calorimetry

    NASA Astrophysics Data System (ADS)

    Chatillon-Colinet, C.; Kleppa, O. J.; Newton, R. C.; Perkins, D., III

    1983-03-01

    A high-temperature solution calorimetric method suitable for thermochemical studies of anhydrous minerals containing Fe 2+ ions has been developed. The method is based on an oxide melt solvent with 52 wt% LiBO 2 and 48 wt% NaBO 2 maintained at a temperature of 750°C. In a first application of this method the enthalpies of solution of synthetic almandine, fayalite, a mixture of fayalite plus quartz on FeSiO 3 composition, and natural quartz were measured. For the reaction: ? the enthalpy change at 1023 K is -3.82 ± 0.87 kcal, based on fayalite, quartz, corundum and almandine, and -5.96 ± 0.90 kcal based on the fayalite plus quartz mixture, corundum, and almandine. These values lead to standard molar enthalpies of formation of almandine from the oxides at 1023 K of -14.10 ± 1.22 kcal and -16.24 ± 1.74 kcal, respectively. The measured enthalpy of formation of almandine is less negative by several kilocalories than values derived from analysis of the phase equilibrium work of HSU (1968), but in closer agreement with the phase equilibrium study of O'NEILL and WOOD (1979) and similar to the phase equilibrium deduction of FROESE (1973). The agreement of the present almandine enthalpy of formation with O'NEILL and WOOD (1979) and FROESE (1973) suggests that almandine entropies at 298 K to be obtained from their studies, in the range 79-81 cal/K, are more nearly correct than the several estimates based on oxide sum and volume-entropy systematics, most of which are much lower.

  19. Dissolved organic matter degradation by sunlight coagulates organo-mineral colloids and produces low-molecular weight fraction of metals in boreal humic waters

    NASA Astrophysics Data System (ADS)

    Oleinikova, Olga V.; Drozdova, Olga Yu.; Lapitskiy, Sergey A.; Demin, Vladimir V.; Bychkov, Andrey Yu.; Pokrovsky, Oleg S.

    2017-08-01

    Photochemical degradation of dissolved organic matter (DOM) is recognized as the major driver of CO2 emission to the atmosphere from the inland waters of high latitudes. In contrast to numerous studies of photo-induced DOM transformation, the behavior of trace element (TE) during photodegradation of boreal DOM remains virtually unknown. Towards a better understanding of concentration, size fractionation and speciation change of DOM and TE in boreal waters subjected to solar radiation, we conducted on-site photo-degradation experiments in stream and bog water collected from a pristine zone of the Northern Karelia (Russian subarctic). The removal of Fe and Al occurred only in the bog water (90% and 50% respectively, over 5 days of reaction), whereas no detectable decrease of dissolved (<0.22 μm) Al and Fe concentration was observed in the boreal stream. A number of low-soluble TE linked to Fe-rich organo-mineral colloids followed the behavior of Fe during bog water exposure to sunlight: Al, P, Ti, V, Cr, As, Y, Zr, REEs, Hf, Th, Pb and U. The second group of elements (Li, B, Mg, Ca, Sr, Ba, Na, K, Rb, Si, Mn, Ni, Cu, Co, Cd, Sb) was indifferent to photodegradation of DOM and exhibited a non-systematic variation (±10-15% from the control) of <0.22 μm fraction in the course of sunlight exposure. The bog water insolation yielded a factor of 3 ± 1 increase of low molecular weight (LMW < 1 kDa) fraction of organic carbon, Al, Fe, U, Mg, Ca, Mn, Co, Ni, Sr, Cd and Ba after 200 h of sunlight exposure compared to the dark control. The LMW< 1 kDa fraction was preferentially enriched in Fe, Al, Ca, Mg and other divalent metals relative to Corg. The climate warming leading to water temperature rise in the boreal zone will intensify the Fe and Al hydroxide coagulation while increasing the production of LMW organic ligands and free metals and metal - organic complexes.

  20. [The effects of the combined use of mineral water with ascorbic acid and rutin experimentally and clinically].

    PubMed

    Polushina, N D; Kartazaeva, V A; Botvineva, L A; Kozhevnikov, S A

    2000-01-01

    Effects of a single and course intake of glucose, ascorbic acid and rutin in combination with mineral water Essentuki N17 on blood levels of glucose, hydrocortisone, ACTH, insulin were studied in 336 Wistar male rats. 80 patients with diabetes mellitus type I and II received a course of ascorutin and mineral water. Mineral water proved able to reduce a hyperglycemic effect of vitamins. A course of mineral water and ascorutin promotes improvement of carbohydrate, lipid metabolism, elevates plasma content of ascorbic acid, diminishes the need in sugar-reducing drugs.

  1. Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds. Sublimation, Vaporization and Fusion Enthalpies From 1880 to 2015. Part 1. C1 - C10

    NASA Astrophysics Data System (ADS)

    Acree, William; Chickos, James S.

    2016-09-01

    A compendium of phase change enthalpies published in 2010 is updated to include the period 1880-2015. Phase change enthalpies including fusion, vaporization, and sublimation enthalpies are included for organic, organometallic, and a few inorganic compounds. Part 1 of this compendium includes organic compounds from C1 to C10. Part 2 of this compendium, to be published separately, will include organic and organometallic compounds from C11 to C192. Sufficient data are presently available to permit thermodynamic cycles to be constructed as an independent means of evaluating the reliability of the data. Temperature adjustments of phase change enthalpies from the temperature of measurement to the standard reference temperature, T = 298.15 K, and a protocol for doing so are briefly discussed.

  2. Calcium Bioavailability from Mineral Waters with Different Mineralization in Comparison to Milk and a Supplement.

    PubMed

    Greupner, Theresa; Schneider, Inga; Hahn, Andreas

    2017-07-01

    The aim of the present study was to compare the bioavailability of calcium from 3 mineral waters with different concentrations of minerals with that of milk and a calcium supplement. A single-center, randomized controlled trial with a crossover design with 21 healthy men and women was conducted at the Institute of Food Science and Human Nutrition, Leibniz University Hannover. The participants consumed the 5 test products providing 300 mg of calcium each on 5 examination days with 1-week wash-out phases in between. Primary outcome variables were the area under the curve of serum calcium levels for 10-hour (AUC 0-10h ) and 24-hour urinary calcium excretion. In all groups, no significant differences in the AUC 0-10h of serum calcium levels as well as in the 24-hour urinary calcium excretion were observed. Likewise, mean changes in serum phosphate and urinary phosphate, as well as serum parathormone, showed no differences between the groups. Given an equivalent bioavailability of calcium in all test products, neither a high concentration of SO 4 2- or of HCO 3 influenced the bioavailability of calcium. Accordingly, the use of mineral water with high concentrations of calcium constitutes a calorie-free calcium source that can improve calcium supply.

  3. Low to Extremely Low Water Abundances Measured in Nominally Anhydrous Minerals in Mafic to Granitic Apollo Rock Clasts

    NASA Technical Reports Server (NTRS)

    Simon, J. I.; Christoffersen, R.; Wang, J.; Alexander, C. M. O'D.; Mills, R. D.; Hauri, E. H.

    2017-01-01

    Lunar sample-based volatile studies have focused on assessing the inventory and distribution of water in the Moon. Some have focused on the relatively young mare basalts and pyroclastic glasses, which result from partial melting of the relatively young lunar mantle. Less certain is the water inventory for the oldest materials available, which have the greater potential to record the earliest history of volatiles in the Moon (and thus provide evidence for the "wet" vs. "dry" accretion hypotheses of the Earth-Moon system. Studies of volatiles in ancient lunar rocks have largely focused on apatite. One recent FTIR (Fourier Transform Infrared Radiometer) study of plagioclase reported a relatively "wet" (approximately 320 parts per million) magma for primordial ferroan anorthosites (FANs). Another, a NanoSIMS study of alkali feldspar, reported a "wet" (approximately 1 weight percentage) felsic magma, but due to the differentiation processes required for silicic magmatism in the lunar crust, predicted an essentially "dry" (less than 100 parts per million) bulk Moon. Thus, despite evidence that appears to complicate the early "dry" Moon paradigm, there is no apparent unanimity among the measurements, even those on apatite. This disparity is clearly seen by the order of magnitude different water estimates for lunar "alkali-rich suite rocks" (Fig. 1). Some of the apparent differences may be explained by recent improvements in the apatite-based water estimates that better account for relative compatibilities of OH-, Cl, and F. In the present work, we seek to expand our understanding of the volatile abundances in early formed lunar magmas, their source reservoirs, and to address the potential role that felsic magmas play on the lunar hydrogen budget over time by employing NanoSIMS analysis of nominally anhydrous minerals.

  4. Binding the Mammalian High Mobility Group Protein AT-hook 2 to AT-Rich Deoxyoligonucleotides: Enthalpy-Entropy Compensation

    PubMed Central

    Joynt, Suzanne; Morillo, Victor; Leng, Fenfei

    2009-01-01

    HMGA2 is a DNA minor-groove binding protein. We previously demonstrated that HMGA2 binds to AT-rich DNA with very high binding affinity where the binding of HMGA2 to poly(dA-dT)2 is enthalpy-driven and to poly(dA)poly(dT) is entropy-driven. This is a typical example of enthalpy-entropy compensation. To further study enthalpy-entropy compensation of HMGA2, we used isothermal-titration-calorimetry to examine the interactions of HMGA2 with two AT-rich DNA hairpins: 5′-CCAAAAAAAAAAAAAAAGCCCCCGCTTTTTTTTTTTTTTTGG-3′ (FL-AT-1) and 5′-CCATATATATATATATAGCCCCCGCTATATATATATATATGG-3′ (FL-AT-2). Surprisingly, we observed an atypical isothermal-titration-calorimetry-binding curve at low-salt aqueous solutions whereby the apparent binding-enthalpy decreased dramatically as the titration approached the end. This unusual behavior can be attributed to the DNA-annealing coupled to the ligand DNA-binding and is eliminated by increasing the salt concentration to ∼200 mM. At this condition, HMGA2 binding to FL-AT-1 is entropy-driven and to FL-AT-2 is enthalpy-driven. Interestingly, the DNA-binding free energies for HMGA2 binding to both hairpins are almost temperature independent; however, the enthalpy-entropy changes are dependent on temperature, which is another aspect of enthalpy-entropy compensation. The heat capacity change for HMGA2 binding to FL-AT-1 and FL-AT-2 are almost identical, indicating that the solvent displacement and charge-charge interaction in the coupled folding/binding processes for both binding reactions are similar. PMID:19450485

  5. Swelling properties of montmorillonite and beidellite clay minerals from molecular simulation: Comparison of temperature interlayer cation, and charge location effects

    DOE PAGES

    Teich-McGoldrick, Stephanie L.; Greathouse, Jeffery A.; Jove-Colon, Carlos F.; ...

    2015-08-27

    In this study, the swelling properties of smectite clay minerals are relevant to many engineering applications including environmental remediation, repository design for nuclear waste disposal, borehole stability in drilling operations, and additives for numerous industrial processes and commercial products. We used molecular dynamics and grand canonical Monte Carlo simulations to study the effects of layer charge location, interlayer cation, and temperature on intracrystalline swelling of montmorillonite and beidellite clay minerals. For a beidellite model with layer charge exclusively in the tetrahedral sheet, strong ion–surface interactions shift the onset of the two-layer hydrate to higher water contents. In contrast, for amore » montmorillonite model with layer charge exclusively in the octahedral sheet, weaker ion–surface interactions result in the formation of fully hydrated ions (two-layer hydrate) at much lower water contents. Clay hydration enthalpies and interlayer atomic density profiles are consistent with the swelling results. Water adsorption isotherms from grand canonical Monte Carlo simulations are used to relate interlayer hydration states to relative humidity, in good agreement with experimental findings.« less

  6. Electromembrane recycling of highly mineralized alkaline blowdown water from evaporative water treatment plants at thermal power stations

    NASA Astrophysics Data System (ADS)

    Chichirova, N. D.; Chichirov, A. A.; Lyapin, A. I.; Minibaev, A. I.; Silov, I. Yu.; Tolmachev, L. I.

    2016-12-01

    Thermal power stations (TPS) are the main source of highly mineralized effluents affecting the environment. An analysis of their water systems demonstrates that alkaline effluents prevail at TPSs. Extraction of an alkali from highly mineralized effluents can make the recycling of effluents economically feasible. A method is proposed of electromembrane recycling of liquid alkaline highly mineralized wastes from TPSs. The process includes electromembrane apparatuses of two types, namely, a diffusion dialysis extractor (DDE) intended for extraction of the alkali from a highly mineralized solution having a complex composition and an electrodialysis concentrator for increasing the concentration of the extracted solution to a value suitable for use in water treatment plants at TPSs. For implementation of the first process (i.e. the extraction of alkali from alkaline-salt solution) various membranes from various manufacturers were studied: CM-PAD and AM-PAD (Ralex, Czechia), MK-40, MA-40, MA-41, MA-414, and MB-2 (OOO OKhK "Shchekinoazot", Russia), AR103-QDF and CR61-CMP (Ionies Inc., USA). The experiments demonstrate that the acceptable degree of separation of the alkali and the salt is achieved in a pair of cation-exchange membranes with the efficiency of separation being higher without an electric field. The highest efficiency was attained with Russian-made membranes (MK-40, OOO OKhK "Shchekinoazot"). A full scale experiment on recycling of highly-mineralized blowdown water from the evaporating water treatment system at the Kazan cogeneration power station No. 3 (TETs-3) was performed in a pilot unit consisting of two electromembrane apparatuses made by UAB "Membraninės Technologijos LT". In the experiments every ton of blowdown water yielded 0.1 t of concentrated alkaline solution with an alkali content of up to 4 wt % and 0.9 t of the softened salt solution suitable for the reuse in the TPS cycle. The power rate is 6 kWh / ton of blowdown water.

  7. Kinetic Study of Denatonium Sorption to Smectite Clay Minerals.

    PubMed

    Crosson, Garry S; Sandmann, Emily

    2013-06-01

    The denatonium cation, as a benzoate salt, is the most bitter cation known to modern society and is frequently added to consumer products to reduce accidental and intentional consumption by humans and animals. Denatonium can enter the environment by accidental discharges, potentially rendering water supplies undrinkable. Interactions of denatonium with soil components ( i.e. , smectite minerals) ultimately control the environmental fate of denatonium, but the current literature is devoid of studies that evaluate denatonium sorption to smectite minerals. This study investigated the mechanism and kinetics of denatonium sorption to smectite clay minerals as a function of smectite type, temperature, pH and ionic strength. Uptake by synthetic mica montmorillonite (Syn-1), Wyoming montmorillonite (SWy-2), and Texas montmorillonite (STx-1b) at 305K was rapid, with equilibrium being reached within 2 min for all clays. Complete removal of denatonium was observed for STx-1b at pH 6.9, while partial removal was observed for Syn-1 and SWy-2. Kinetic behavior of SWy-2 and Syn-1 is consistent with a pseudo-second-order model at 305K. An activation energy of +25.9 kJ/mol was obtained for sorption to Syn-1 and was independent of temperature between 286K and 338K. Activation-free energy (Δ G *), activation enthalpy (Δ H *), and activation entropy (Δ S *) for Syn-1 were found to be +62.91 kJ/mol, +23.36 kJ/mol, and -0.130 kJ/(K·mol), respectively. Sorption capacities at pH 3.6, 6.9, and 8.2 were constant at 1.3×10 -2 g denatonium/g clay; however, the kinetic rate constant increased by 56%, going from acidic to basic solution conditions. Distribution coefficients were negatively correlated with ionic strength, suggesting cation exchange. Collectively, results suggested that smectite minerals can serve as efficient sinks for denatonium cations. This is much-needed information for agencies developing regulations regarding denatonium usage and for water treatment professionals

  8. Bulk Enthalpy Calculations in the Arc Jet Facility at NASA ARC

    NASA Technical Reports Server (NTRS)

    Thompson, Corinna S.; Prabhu, Dinesh; Terrazas-Salinas, Imelda; Mach, Jeffrey J.

    2011-01-01

    The Arc Jet Facilities at NASA Ames Research Center generate test streams with enthalpies ranging from 5 MJ/kg to 25 MJ/kg. The present work describes a rigorous method, based on equilibrium thermodynamics, for calculating the bulk enthalpy of the flow produced in two of these facilities. The motivation for this work is to determine a dimensionally-correct formula for calculating the bulk enthalpy that is at least as accurate as the conventional formulas that are currently used. Unlike previous methods, the new method accounts for the amount of argon that is present in the flow. Comparisons are made with bulk enthalpies computed from an energy balance method. An analysis of primary facility operating parameters and their associated uncertainties is presented in order to further validate the enthalpy calculations reported herein.

  9. BMI, hypertension and low bone mineral density in adult men and women.

    PubMed

    Szklarska, Alicja; Lipowicz, Anna

    2012-08-01

    The aim of this work was to estimate the body mass index (BMI) at which risk of hypertension is lowest in men and women, while concurrently considering the protective role of adipose tissue in osteoporosis. Healthy, occupationally active inhabitants of the city of Wrocław, Poland, 1218 women and 434 men were studied. BMI, systolic and diastolic blood pressures, bone mineral density (BMD) of the trabecular compartment and distal radius of the non-dominant hand were recorded. Overweight in young women (≤45 years) was associated with increased risk of hypertension, whereas the risk of low bone mineral was decreased for the same BMI. In older women (>45 years), a BMI>27 was the threshold for increased risk of hypertension. In this age group, extremely slim women (BMI<21) had the highest risk of low bone mineral density. In younger males (≤45 years), risk of hypertension was lowest among the thinnest subjects (BMI<21). Increase in BMI over 21 kg/m(2) increased the risk of hypertension. The probability of low bone mineral density was the same in all BMI categories of men. In older men (>45 years), the thinnest (BMI<21) had higher risk of hypertension. To begin from BMI=25 kg/m(2), there was a monotonous increase in risk of hypertension in men. Higher risk for low bone mineral density was observed in older men with the BMI<23. Among younger adults, risk of hypertension and low bone mineral density increase at BMI≥21 kg/m(2) in men and BMI≥23 kg/m(2) in women. Among older men and women, the BMI threshold was 27 kg/m(2). Copyright © 2012 Elsevier GmbH. All rights reserved.

  10. Urban net-zero water treatment and mineralization: experiments, modeling and design.

    PubMed

    Englehardt, James D; Wu, Tingting; Tchobanoglous, George

    2013-09-01

    Water and wastewater treatment and conveyance account for approximately 4% of US electric consumption, with 80% used for conveyance. Net zero water (NZW) buildings would alleviate demands for a portion of this energy, for water, and for the treatment of drinking water for pesticides and toxic chemical releases in source water. However, domestic wastewater contains nitrogen loads much greater than urban/suburban ecosystems can typically absorb. The purpose of this work was to identify a first design of a denitrifying urban NZW treatment process, operating at ambient temperature and pressure and circum-neutral pH, and providing mineralization of pharmaceuticals (not easily regulated in terms of environmental half-life), based on laboratory tests and mass balance and kinetic modeling. The proposed treatment process is comprised of membrane bioreactor, iron-mediated aeration (IMA, reported previously), vacuum ultrafiltration, and peroxone advanced oxidation, with minor rainwater make-up and H2O2 disinfection residual. Similar to biological systems, minerals accumulate subject to precipitative removal by IMA, salt-free treatment, and minor dilution. Based on laboratory and modeling results, the system can produce potable water with moderate mineral content from commingled domestic wastewater and 10-20% rainwater make-up, under ambient conditions at individual buildings, while denitrifying and reducing chemical oxygen demand to below detection (<3 mg/L). While economics appear competitive, further development and study of steady-state concentrations and sludge management options are needed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Chemical dispersion of oil with mineral fines in a low temperature environment.

    PubMed

    Wang, Weizhi; Zheng, Ying; Lee, Kenneth

    2013-07-15

    The increasing risks of potential oil spills in the arctic regions, which are characterized by low temperatures, are a big challenge. The traditional dispersant method has shown limited effectiveness in oil cleanup. This work studied the role of mineral fines in the formation of oil-mineral aggregates (OMAs) at low temperature (0-4 °C) environment. The loading amount of minerals and dispersant with different dispersant and oil types were investigated under a full factorial design. The shapes and sizes of OMAs were analyzed. Results showed that the behavior of OMA formation differs when dispersant and mineral fines are used individually or together. Both the experimental and microscopic results also showed the existence of optimal dispersant to oil ratios and mineral to oil ratios. In general, poor oil removal performance was observed for more viscous oil. Corexit 9500 performed better than Corexit 9527 with various oils, in terms of oil dispersion and OMA formation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Formation enthalpies for transition metal alloys using machine learning

    NASA Astrophysics Data System (ADS)

    Ubaru, Shashanka; Miedlar, Agnieszka; Saad, Yousef; Chelikowsky, James R.

    2017-06-01

    The enthalpy of formation is an important thermodynamic property. Developing fast and accurate methods for its prediction is of practical interest in a variety of applications. Material informatics techniques based on machine learning have recently been introduced in the literature as an inexpensive means of exploiting materials data, and can be used to examine a variety of thermodynamics properties. We investigate the use of such machine learning tools for predicting the formation enthalpies of binary intermetallic compounds that contain at least one transition metal. We consider certain easily available properties of the constituting elements complemented by some basic properties of the compounds, to predict the formation enthalpies. We show how choosing these properties (input features) based on a literature study (using prior physics knowledge) seems to outperform machine learning based feature selection methods such as sensitivity analysis and LASSO (least absolute shrinkage and selection operator) based methods. A nonlinear kernel based support vector regression method is employed to perform the predictions. The predictive ability of our model is illustrated via several experiments on a dataset containing 648 binary alloys. We train and validate the model using the formation enthalpies calculated using a model by Miedema, which is a popular semiempirical model used for the prediction of formation enthalpies of metal alloys.

  13. Potential for Sulfide Mineral Deposits in Australian Waters

    NASA Astrophysics Data System (ADS)

    McConachy, Timothy F.

    The world is witnessing a paradigm shift in relation to marine mineral resources. High-value seafloor massive sulfides at active convergent plate boundaries are attracting serious commercial attention. Under the United Nations Convention on the Law of the Sea, maritime jurisdictional zones will increase by extending over continental margins and ocean basins. For Australia, this means a possible additional 3.37 million km2 of seabed. Australia's sovereign responsibility includes, amongst other roles, the management of the exploitation of nonliving resources and sea-bed mining. What, therefore, is the potential in Australia's marine jurisdiction for similar deposits to those currently attracting commercial attention in neighboring nations and for other types/styles of sulfide deposits? A preliminary review of opportunities suggests the following: (i) volcanogenic copper—lead—zinc—silver—gold mineralization in fossil arcs and back arcs in eastern waters Norfolk Ridge and the Three Kings Ridge; (ii) Mississippi Valley-type lead—zinc—silver mineralization in the NW Shelf area; (iii) ophiolite-hosted copper mineralization in the Macquarie Ridge Complex in the Southern Ocean; and (iv) submerged extensions of prospective land-based terranes, one example being offshore Gawler Craton for iron oxide—copper—gold deposits. These areas would benefit from pre-competitive surveys of detailed swath bathymetry mapping, geophysical surveys, and sampling to help build a strategic inventory of future seafloor mineral resources for Australia.

  14. A compilation of rate parameters of water-mineral interaction kinetics for application to geochemical modeling

    USGS Publications Warehouse

    Palandri, James L.; Kharaka, Yousif K.

    2004-01-01

    Geochemical reaction path modeling is useful for rapidly assessing the extent of water-aqueous-gas interactions both in natural systems and in industrial processes. Modeling of some systems, such as those at low temperature with relatively high hydrologic flow rates, or those perturbed by the subsurface injection of industrial waste such as CO2 or H2S, must account for the relatively slow kinetics of mineral-gas-water interactions. We have therefore compiled parameters conforming to a general Arrhenius-type rate equation, for over 70 minerals, including phases from all the major classes of silicates, most carbonates, and many other non-silicates. The compiled dissolution rate constants range from -0.21 log moles m-2 s-1 for halite, to -17.44 log moles m-2 s-1 for kyanite, for conditions far from equilibrium, at 25 ?C, and pH near neutral. These data have been added to a computer code that simulates an infinitely well-stirred batch reactor, allowing computation of mass transfer as a function of time. Actual equilibration rates are expected to be much slower than those predicted by the selected computer code, primarily because actual geochemical processes commonly involve flow through porous or fractured media, wherein the development of concentration gradients in the aqueous phase near mineral surfaces, which results in decreased absolute chemical affinity and slower reaction rates. Further differences between observed and computed reaction rates may occur because of variables beyond the scope of most geochemical simulators, such as variation in grain size, aquifer heterogeneity, preferred fluid flow paths, primary and secondary mineral coatings, and secondary minerals that may lead to decreased porosity and clogged pore throats.

  15. Small-sized microplastics and pigmented particles in bottled mineral water.

    PubMed

    Oßmann, Barbara E; Sarau, George; Holtmannspötter, Heinrich; Pischetsrieder, Monika; Christiansen, Silke H; Dicke, Wilhelm

    2018-09-15

    Up to now, only a few studies about microparticle contamination of bottled mineral water have been published. The smallest analysed particle size was 5 μm. However, due to toxicological reasons, especially microparticles smaller than 1.5 μm are critically discussed. Therefore, in the present study, 32 samples of bottled mineral water were investigated for contamination by microplastics, pigment and additive particles. Due to the application of aluminium coated polycarbonate membrane filters and micro-Raman spectroscopy, a lowest analysed particle size of 1 μm was achieved. Microplastics were found in water from all bottle types: in single use and reusable bottles made of poly(ethylene terephthalate) (PET) as well as in glass bottles. The amount of microplastics in mineral water varied from 2649 ± 2857 per litre in single use PET bottles up to 6292 ± 10521 per litre in glass bottles. While in plastic bottles, the predominant polymer type was PET; in glass bottles various polymers such as polyethylene or styrene-butadiene-copolymer were found. Hence, besides the packaging itself, other contamination sources have to be considered. Pigment particles were detected in high amounts in reusable, paper labelled bottles (195047 ± 330810 pigment particles per litre in glass and 23594 ± 25518 pigment particles per litre in reusable paper labelled PET bottles). Pigment types found in water samples were the same as used for label printing, indicating the bottle cleaning process as possible contamination route. Furthermore, on average 708 ± 1024 particles per litre of the additive Tris(2,4-di-tert-butylphenyl)phosphite were found in reusable PET bottles. This additive might be leached out from the bottle material itself. Over 90% of the detected microplastics and pigment particles were smaller than 5 μm and thus not covered by previous studies. In summary, this is the first study reporting about microplastics, pigment and additive particles

  16. Biomimetic mineral self-organization from silica-rich spring waters.

    PubMed

    García-Ruiz, Juan Manuel; Nakouzi, Elias; Kotopoulou, Electra; Tamborrino, Leonardo; Steinbock, Oliver

    2017-03-01

    Purely inorganic reactions of silica, metal carbonates, and metal hydroxides can produce self-organized complex structures that mimic the texture of biominerals, the morphology of primitive organisms, and that catalyze prebiotic reactions. To date, these fascinating structures have only been synthesized using model solutions. We report that mineral self-assembly can be also obtained from natural alkaline silica-rich water deriving from serpentinization. Specifically, we demonstrate three main types of mineral self-assembly: (i) nanocrystalline biomorphs of barium carbonate and silica, (ii) mesocrystals and crystal aggregates of calcium carbonate with complex biomimetic textures, and (iii) osmosis-driven metal silicate hydrate membranes that form compartmentalized, hollow structures. Our results suggest that silica-induced mineral self-assembly could have been a common phenomenon in alkaline environments of early Earth and Earth-like planets.

  17. Radium Adsorption to Iron Bearing Minerals in Variable Salinity Waters

    NASA Astrophysics Data System (ADS)

    Chen, M.; Kocar, B. D.

    2014-12-01

    Radium is a common, naturally occurring radioactive metal found in many subsurface environments. Radium isotopes are a product of natural uranium and thorium decay, and are particularly abundant within groundwaters where minimal flux leads to accumulation within porewaters. Radium has been used as a natural tracer to estimate submarine groundwater discharge (SGD) [1], where the ratios of various radium isotopes are used to estimate total groundwater flux to and from the ocean [2]. Further, it represents a substantial hazard in waste water produced after hydraulic fracturing for natural gas extraction [3], resulting in a significant risk of environmental release and increased cost for water treatment or disposal. Adsorption to mineral surfaces represents a primary pathway of radium retention within subsurface environments. For SGD studies, it is important to understand adsorption processes to correctly estimate GW fluxes, while in hydraulic fracturing, radium adsorption to aquifer solids will mediate the activities of radium within produced water. While some studies of radium adsorption to various minerals have been performed [4], there is a limited understanding of the surface chemistry of radium adsorption, particularly to iron-bearing minerals such as pyrite, goethite and ferrihydrite. Accordingly, we present the results of sorption experiments of radium to a suite of iron-bearing minerals representative of those found within deep saline and near-surface (freshwater) aquifers, and evaluate impacts of varying salinity solutions through the use of artificial groundwater, seawater, and shale formation brine. Further, we explore the impacts of pyrite oxidation and ferrihydrite transformation to other iron-bearing secondary minerals on the retention of radium. This work lays the groundwork for further study of radium use as a tracer for SGD, as well as understanding mechanisms of radium retention and release from deep aquifer materials following hydraulic fracturing

  18. Measuring water adsorption on mineral surfaces in air, CO2, and supercritical CO2 with a quartz-crystal microbalance

    NASA Astrophysics Data System (ADS)

    Bryan, C. R.; Wells, R. K.; Burton, P. D.; Heath, J. E.; Dewers, T. A.; Wang, Y.

    2011-12-01

    Carbon sequestration via underground storage in geologic formations is a proposed approach for reducing industrial CO2 emissions. However, current models for carbon injection and long-term storage of supercritical CO2 (scCO2) do not consider the development and stability of adsorbed water films at the scCO2-hydrophilic mineral interface. The thickness and properties of the water films control the surface tension and wettability of the mineral surface, and on the core scale, affect rock permeability, saturation, and capillary properties. The film thickness is strongly dependent upon the activity of water in the supercritical fluid, which will change as initially anhydrous scCO2 absorbs water from formation brine. As described in a companion paper by the coauthors, the thickness of the adsorbed water layer is controlled by the disjoining pressure; structural and van der Waals components dominate at low water activity, while electrostatic forces become more important with increasing film thickness (higher water activities). As scCO2 water activity and water layer thickness increase, concomitant changes in mineral surface properties and reservoir/caprock hydrologic properties will affect the mobility of the aqueous phase and of scCO2. Moreover, the development of a water layer may be critical to mineral dissolution reactions in scCO2. Here, we describe the use of a quartz-crystal microbalance (QCM) to monitor adsorption of water by mineral surfaces. QCMs utilize a piezoelectrically-stimulated quartz wafer to measure adsorbed or deposited mass via changes in vibrational frequency. When used to measure the mass of adsorbed liquid films, the frequency response of the crystal must be corrected for the viscoelastic, rather than elastic, response of the adsorbed layer. Results are presented for adsorption to silica in N2 and CO2 at one bar, and in scCO2. Additional data are presented for water uptake by clays deposited on a QCM wafer. In this case, water uptake occurs by the

  19. Determination of vaporization enthalpies of polychlorinated biphenyls by correlation gas chromatography.

    PubMed

    Puri, S; Chickos, J S; Welsh, W J

    2001-04-01

    The vaporization enthalpies of 16 polychlorinated biphenyls have been determined by correlation gas chromatography. This study was prompted by the realization that the vaporization enthalpy of the standard compounds used in previous studies, octadecane and eicosane, were values measured at 340 and 362 K, respectively, rather than at 298 K. Adjustment to 298 K amounts to a 7-8 kJ/mol increment in the values. With the inclusion of this adjustment, vaporization enthalpies evaluated by correlation gas chromatography are in good agreement with the values determined previously in the literature. The present results are based on the vaporization enthalpies of several standards whose values are well established in the literature. The standards include a variety of n-alkanes and various chlorinated hydrocarbons. The vaporization enthalpies of PCBs increased with the number of chlorine atoms and were found to be larger for meta- and para-substituted polychlorinated biphenyls.

  20. Solubility of crystalline organic compounds in high and low molecular weight amorphous matrices above and below the glass transition by zero enthalpy extrapolation.

    PubMed

    Amharar, Youness; Curtin, Vincent; Gallagher, Kieran H; Healy, Anne Marie

    2014-09-10

    Pharmaceutical applications which require knowledge of the solubility of a crystalline compound in an amorphous matrix are abundant in the literature. Several methods that allow the determination of such data have been reported, but so far have only been applicable to amorphous polymers above the glass transition of the resulting composites. The current work presents, for the first time, a reliable method for the determination of the solubility of crystalline pharmaceutical compounds in high and low molecular weight amorphous matrices at the glass transition and at room temperature (i.e. below the glass transition temperature), respectively. The solubilities of mannitol and indomethacin in polyvinyl pyrrolidone (PVP) K15 and PVP K25, respectively were measured at different temperatures. Mixtures of undissolved crystalline solute and saturated amorphous phase were obtained by annealing at a given temperature. The solubility at this temperature was then obtained by measuring the melting enthalpy of the crystalline phase, plotting it as a function of composition and extrapolating to zero enthalpy. This new method yielded results in accordance with the predictions reported in the literature. The method was also adapted for the measurement of the solubility of crystalline low molecular weight excipients in amorphous active pharmaceutical ingredients (APIs). The solubility of mannitol, glutaric acid and adipic acid in both indomethacin and sulfadimidine was experimentally determined and successfully compared with the difference between their respective calculated Hildebrand solubility parameters. As expected from the calculations, the dicarboxylic acids exhibited a high solubility in both amorphous indomethacin and sulfadimidine, whereas mannitol was almost insoluble in the same amorphous phases at room temperature. This work constitutes the first report of the methodology for determining an experimentally measured solubility for a low molecular weight crystalline solute

  1. [The effect of potable mineral waters on the hormonal and psychological status (experimental and clinical research)].

    PubMed

    Polushina, N D; Babina, L M; Shvedunova, L N

    1994-01-01

    Experiments on 80 Wistar rats revealed the ability of Essentuki mineral waters to stimulate the reserves and sensitivity of the intestinal serotonin-producing system. A clinical trial on two groups of children (exposed to low-dose ionizing radiation or with posttraumatic astheno-neurotic syndrome) found out pronounced positive changes in the psychological status of the children which progressed in correlation with an increase of the blood serotonin levels.

  2. Free Enthalpy Differences between α-, π-, and 310-Helices of an Atomic Level Fine-Grained Alanine Deca-Peptide Solvated in Supramolecular Coarse-Grained Water.

    PubMed

    Lin, Zhixiong; Riniker, Sereina; van Gunsteren, Wilfred F

    2013-03-12

    Atomistic molecular dynamics simulations of peptides or proteins in aqueous solution are still limited to the multi-nanosecond time scale and multi-nanometer range by computational cost. Combining atomic solutes with a supramolecular solvent model in hybrid fine-grained/coarse-grained (FG/CG) simulations allows atomic detail in the region of interest while being computationally more efficient. We used enveloping distribution sampling (EDS) to calculate the free enthalpy differences between different helical conformations, i.e., α-, π-, and 310-helices, of an atomic level FG alanine deca-peptide solvated in a supramolecular CG water solvent. The free enthalpy differences obtained show that by replacing the FG solvent by the CG solvent, the π-helix is destabilized with respect to the α-helix by about 2.5 kJ mol(-1), and the 310-helix is stabilized with respect to the α-helix by about 9 kJ mol(-1). In addition, the dynamics of the peptide becomes faster. By introducing a FG water layer of 0.8 nm around the peptide, both thermodynamic and dynamic properties are recovered, while the hybrid FG/CG simulations are still four times more efficient than the atomistic simulations, even when the cutoff radius for the nonbonded interactions is increased from 1.4 to 2.0 nm. Hence, the hybrid FG/CG model, which yields an appropriate balance between reduced accuracy and enhanced computational speed, is very suitable for molecular dynamics simulation investigations of biomolecules.

  3. Experience Gained on Direct Use of Low Enthalpy Energy in Hotel do Parque, S. Pedro do Sul, Portugal

    NASA Astrophysics Data System (ADS)

    Ferreira Gomes, L. M.; Neves Trota, A. P.; Reis Afonso de Albuquerque, F. J.

    2017-12-01

    Despite the high number of thermal flowing springs in Portugal mainland (up to 52 hot springs), ranging temperatures from 20 °C to 77 °C, and with significant water flow rate, few district heating system were implemented in Portugal. Here we present the São Pedro do Sul district heating system, located northern of Portugal. The thermal power plant was designed, completed, and commissioned in 2001 allowing the utilization of the geothermal heat by local users, as Hotel do Parque. The district heating system sums about 15 years of utilization without interruption and with minor drawbacks. On this paper we present the project overview along with thermal power plant specifications and data numbers. Heat comes from a 16.9 L/s of thermal water supplied by a natural spring and a nearby well. Heat from the spring and well sources is transferred to a secondary low mineralized water system by a plate heat exchanger, allowing the heating of space and domestic waters of hotel areas. Based on a theoretically cascade direct use of heat from a 67 °C to a 20 °C water temperature range, available heat totals 29.1*106 kWh yearly. However, past and actual use of heat only reaches around 1.6% of that figure. By comparing with fossil heat sources, actual use of a natural heat source reduces a theoretically amount of 117.9 ton of CO2 emissions by year. The successful use of this district heating system can promote local expansion of new users and other possible heat uses of this renewable energy, giving chance for the district heating system saturation.

  4. The effects of the calcium-magnesium-bicarbonate content in thermal mineral water on chronic low back pain: a randomized, controlled follow-up study

    NASA Astrophysics Data System (ADS)

    Tamás, Gáti; Katalin, Tefner Ildikó; Lajos, Kovács; Katalin, Hodosi; Tamás, Bender

    2018-01-01

    The aim of this study was to investigate the effects of balneotherapy on chronic low back pain. This is a minimized, follow-up study evaluated according to the analysis of intention to treat. The subjects included in the study were 105 patients suffering from chronic low back pain. The control group (n = 53) received the traditional musculoskeletal pain killer treatment, while the target group (n = 52) attended thermal mineral water treatment for 3 weeks for 15 occasions on top of the usual musculoskeletal pain killer treatment. The following parameters were measured before, right after, and 9 weeks after the 3-week therapy: the level of low back pain in rest and the level during activity are tested using the Visual Analog Scale (VAS); specific questionnaire on the back pain (Oswestry); and a questionnaire on quality of life (EuroQual-5D). All of the investigated parameters improved significantly (p < 0.001) in the target group by the end of the treatment compared to the base period, and this improvement was persistent during the follow-up period. There were no significant changes in the measured parameters in the control group. Based on our results, balneotherapy might have favorable impact on the clinical parameters and quality of life of patients suffering from chronic low back pain.

  5. The effects of the calcium-magnesium-bicarbonate content in thermal mineral water on chronic low back pain: a randomized, controlled follow-up study

    NASA Astrophysics Data System (ADS)

    Gáti, Tamás; Tefner, Ildikó Katalin; Kovács, Lajos; Hodosi, Katalin; Bender, Tamás

    2018-05-01

    The aim of this study was to investigate the effects of balneotherapy on chronic low back pain. This is a minimized, follow-up study evaluated according to the analysis of intention to treat. The subjects included in the study were 105 patients suffering from chronic low back pain. The control group ( n = 53) received the traditional musculoskeletal pain killer treatment, while the target group ( n = 52) attended thermal mineral water treatment for 3 weeks for 15 occasions on top of the usual musculoskeletal pain killer treatment. The following parameters were measured before, right after, and 9 weeks after the 3-week therapy: the level of low back pain in rest and the level during activity are tested using the Visual Analog Scale (VAS); specific questionnaire on the back pain (Oswestry); and a questionnaire on quality of life (EuroQual-5D). All of the investigated parameters improved significantly ( p < 0.001) in the target group by the end of the treatment compared to the base period, and this improvement was persistent during the follow-up period. There were no significant changes in the measured parameters in the control group. Based on our results, balneotherapy might have favorable impact on the clinical parameters and quality of life of patients suffering from chronic low back pain.

  6. Enthalpy measurement of coal-derived liquids. Technical progress report, November 1982-January 1983

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kidnay, A.J.; Yesavage, V.F.

    The objective of this research is to measure the enthalpy for representative coal-derived liquids and model compounds over the pressure and temperature regions most likely to be encountered in both liquefaction and processing systems, and to prepare from the data an enthalpy correlation suitable for process design calculations. The correlational effort this past quarter on the enthalpy of coal-derived syncrudes and model compounds has emphasized the experimental determination of a correlating factor for association in coal liquids. As in previous work, the degree of association is to be related to cryoscopic molecular weight determinations on the coal liquids. To thismore » end, work on and an evaluationof a cryoscopic molecular weight apparatus was completed this quarter. Molecular weights of coal liquids determined by the standard Beckman freezing point depression apparatus were consistently low (5 to 10%). After modifications of the apparatus, it was tested with the following compounds: hexane, dodecane, m-xylene and naphthalene. Benzene was the solvent used. However, the molecular weight measurements were again consistently lower than the true values, and in many cases the experimental error was greater than that of the Beckman apparatus.« less

  7. Sodium-rich carbonated natural mineral water ingestion and blood pressure.

    PubMed

    Santos, Alejandro; Martins, Maria João; Guimarães, João Tiago; Severo, Milton; Azevedo, Isabel

    2010-02-01

    There is a strong positive correlation between sodium chloride intake and hypertension. In industrialized countries the ingestion of carbonated and non-carbonated mineral water is an important source of calorie-free fluids. The mineral content of these waters varies greatly, with many brands containing high levels of sodium. However, some mineral waters contain greater amounts of bicarbonate instead of chloride as the anion associated with the sodium cation. This is relevant because it is well established that the effect of sodium on blood pressure depends on the corresponding anion. Additionally the pressor effect of sodium bicarbonate is much lower than that of equivalent amounts of sodium chloride. The aim of our work was to evaluate the effect of ingesting a sodium-rich carbonated mineral water (Agua das Pedras) on blood pressure values in normotensive individuals. This crossover, non-blinded study evaluated 17 individuals (9 female and 8 male), aged 24-53 years, median body mass index (BMI) < 23, randomly allocated in two groups, ingesting 500 ml/day of Agua das Pedras or Agua Vitalis. Each arm of the study lasted 7 weeks, with 6 weeks of washout between them. Twenty-four hour urinary samples were collected at the beginning and end of each arm to determine pH and sodium and potassium excretion. Blood pressure and body weight were measured weekly throughout the study. A mixed-effects model was used to compare groups (p < 0.05). The Wilcoxon test was used to analyze electrolyte excretion. No differences were observed in blood pressure values between treatments or from baseline values. We found a positive correlation between BMI and blood pressure. The daily ingestion of 500 ml of Agua das Pedras had no effect on blood pressure. A study by Schorr and co-workers found that the ingestion of bicarbonate-rich water (1.5 l/day) had hypotensive effects in an elderly population. However, these results should be verified in hypertensive subjects, who are more likely to

  8. A method to simultaneously determine sorption isotherms and sorption enthalpies with a double twin microcalorimeter

    NASA Astrophysics Data System (ADS)

    Wadso, Lars; Markova, Natalia

    2002-07-01

    Sorption of vapors of water, ethanol, and other liquids on solids like pharmaceuticals, textiles and food stuffs are of both practical and theoretical importance. In this article we present a technique to simultaneously measure sorption isotherms and sorption enthalpies. The sample is contained in one end of a sorption vessel. In the other end a vaporizable liquid is introduced to start the measurement. Mass transfer from the liquid to the sample is by vapor diffusion and the rate of mass transfer is calculated from the measured thermal power of vaporization. Simultaneously, the thermal power of sorption is measured and from this one may calculate the differential enthalpy of sorption. The thermal power measurements are made by inserting the sorption vessel in an isothermal double twin microcalorimeter.

  9. Radiation dose to the Malaysian populace via the consumption of bottled mineral water

    NASA Astrophysics Data System (ADS)

    Khandaker, Mayeen Uddin; Nasir, Noor Liyana Mohd; Zakirin, Nur Syahira; Kassim, Hasan Abu; Asaduzzaman, Khandoker; Bradley, D. A.; Zulkifli, M. Y.; Hayyan, Adeeb

    2017-11-01

    Due to the geological makeup of the various water bodies, mineral- and groundwater can be expected to contain levels of naturally occurring radioactive material (NORM) exceeding that of tap and surface water. Acknowledging mineral water to form a vital component of the intake in maintaining the healthy life of an individual, it nevertheless remains important to study the associated radiological implications of NORM content, especially in regard to the consumption of bottled mineral water, the presence of which is prevalent in modern urban society. In present study, various brands of bottled mineral waters that are commonly available in Malaysia were obtained from local markets, the presence of NORM subsequently being assessed by HPGe γ-ray spectrometry. The activity concentrations of the radionuclides of particular interest, 226Ra, 232Th and 40K, were found to be within the respective ranges of 1.45±0.28‒3.30±0.43, 0.65±0.18‒3.39±0.38 and 21.12±1.74‒25.31±1.84 Bq/L. The concentrations of 226Ra, of central importance in radiological risk assessment, exceed the World Health Organisation (WHO, 2011) recommended maximum permissible limit of 1.0 Bq/L; for all three radionuclides taken together, the annual effective doses are greater than the WHO recommended limit of 0.1 mSv/y, a matter of especial concern for those in the developmental stages of life.

  10. Modifications of biological effects of drinking mineral waters in Pyatigorsk resort

    NASA Astrophysics Data System (ADS)

    Reps, Valentina; Efimenko, Natalia; Abramtsova, Anna; Kozlova, Victoria; Sagradyan, Gayne; Tovbushenko, Tatiana; Kotova, Margarita

    2017-04-01

    A variety of types of drinking mineral waters (MW) of Pyatigorsk Deposit (PD) is explained by its structural style and hydrogeological conditions. In resort conditions the most widely used mineral waters are acidulated and carbonate chloride sodium hydrocarbonate MW. It has been shown earlier that natural MW have a high biological exposure potential on exchange processes both in norm and during pathological metabolic changes [1, 2]. We have studied some modification options of the composition of natural drinking mineral waters (MW) in Pyatigorsk resort to increase their rehabilitation potential. In the experiment on 110 male-rats of Wistar line there have been examined some biological effects of a course drinking intake (21 days) of natural MW from the spring that has sulphate-hydrocarbonate-chloride calcium-sodic composition with ferrum elevated level (3-5 mg/dm3), mineralization of 5,0-5,2 g/dm3, CO2 1,3-2,2 g/dm3, daily flow of 10-86 m3/day, temperature from 14 to 370C at the wellhead and MW modified by nanoparticles (NP) of Se (0,04 mg/kg, d - 35 nm) and Ag nanoparticles (0,001 mg/kg, d - 30 nm). One of the mechanisms of selenium influence on carbohydrate metabolism is the regulation of blood glucose level and its utilization by tissues. After the course by the studied MW type there has been noticed Ca-ATPase level reduction in liver against the background of insulin downregulation and glycemia elevation in blood serum of the rats [1]. There has been also observed glucagon retrogression in the blood of the labolatory animals after the treatment course by natural MW in 3 times (p<0,001) and after the course by MW in combination with Se nanoparticles in 1,5 times (p<0,01) in comparison with the control (fresh water). At the same time glucose level authentically increased only after the course by natural MW - 4,8 (4,6-5 ‰) mmol/l in comparison with the control - 4 (4 - 4,4 ‰) mmol/l. Insulin concentration did not change with the animals after the watering

  11. The maximum water storage capacities in nominally anhydrous minerals in the mantle transition zone and lower mantle

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Yurimoto, H.

    2012-12-01

    Water is the most important volatile component in the Earth, and affects the physicochemical properties of mantle minerals, e.g. density, elastic property, electrical conductivity, thermal conductivity, rheological property, melting temperature, melt composition, element partitioning, etc. So many high pressure experiments have been conducted so far to determine the effect of water on mantle minerals. To clarify the maximum water storage capacity in nominally anhydrous mantle minerals in the mantle transition zone and lower mantle is an important issue to discuss the possibility of the existence of water reservoir in the Earth mantle. So we have been clarifying the maximum water storage capacity in mantle minerals using MA-8 type (KAWAI-type) high pressure apparatus and SIMS (secondary ion mass spectroscopy). Upper mantle mineral, olivine can contain ~0.9 wt% H2O in the condition just above 410 km discontinuity in maximum (e.g. Chen et al., 2002; Smyth et al., 2006). On the other hand, mantle transition zone mineral, wadsleyite and ringwoodite can contain significant amount (about 2-3 wt.%) of H2O (e.g. Inoue et al., 1995, 1998, 2010; Kawamoto et al., 1996; Ohtani et al., 2000). But the lower mantle mineral, perovskite can not contain significant amount of H2O, less than ~0.1 wt% (e.g. Murakami et al., 2002; Inoue et al., 2010). In addition, garnet and stishovite also can not contain significant amount of H2O (e.g. Katayama et al., 2003; Mookherjee and Karato, 2010; Litasov et al., 2007). On the other hand, the water storage capacities of mantle minerals are supposed to be significantly coupled with Al by a substitution with Mg2+, Si4+ or Mg2+ + Si4+, because Al3+ is the trivalent cation, and H+ is the monovalent cation. To clarify the degree of the substitution, the water contents and the chemical compositions of Al-bearing minerals in the mantle transition zone and the lower mantle were also determined in the Al-bearing systems with H2O. We will introduce the

  12. Desalination of Ground Water Minerals (Case Study: Kashan Desert in Iran)

    NASA Astrophysics Data System (ADS)

    Mahani, S. E.; Esmaeli Mahani, M.; Siavoshi, F.; Jafari, M.

    2009-12-01

    The present study focuses on testing quality and desalination of minerals from ground water that is used as the only source of water supply particularly for drinking in the Kashan Desert in Iran. About 14.2 cubic meter water/year from 59 wells, with the average depth of 120 meter, are used for drinking and personal usage in the selected study area. To test the quality of ground water, in general, salinity of minerals such as: chloride (Cl), sulfate (SO4), carbonate (CO3), bicarbonate (HCO3), potassium (K), sodium (Na), calcium (Ca), and magnesium (Mg), as well as PH, Total Dissolved Solids (TDS), Electric Conductivity (EC), and Temperature (T) are measured. EC and TDS in the deserts and arid areas are usually very high because of lack of rainfall, higher temperature, and high rate of evaporation. If the TDS is greater than 1000 mg/l, ground water needs to be desalinated. The TDS of ground water samples in Kashan Desert is greater than 2500 mg/l, which is higher than international World Health Organization (WHO) and Environmental Protection Agency (EPA) standard values. Conventional treatment can not be the only solution for making Kashan Desert ground water that much pure that can be used as fresh water for drinking because EC, Mg, Na, Cl, and SO4 are also higher than standard values. Various techniques such as: Ion Exchange (IX), Microfiltration (MF), Ultra Filtration (UF), Nano Filtration (NF), Electro Dialysis (ED), and Reserve Osmosis (RO) are examined to desalinate above mentioned minerals. Based on molecular weight and diameter of chemical particles which should be removed, in addition to experiences of operational groups in Iran, the RO technique has been selected as the best methodology. The results show that the RO technique could improve the quality of Kashan Desert ground water by comparison with the standard fresh water up to 95% to 99%.

  13. Enthalpy of Formation of N 2 H 4 (Hydrazine) Revisited

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Feller, David; Bross, David H.; Ruscic, Branko

    2017-08-02

    In order to address the accuracy of the long-standing experimental enthalpy of formation of gas-phase hydrazine, fully confirmed in earlier versions of Active Thermochemical Tables (ATcT), the provenance of that value is re-examined in light of new high-end calculations of the Feller-Peterson-Dixon (FPD) variety. An overly optimistic determination of the vaporization enthalpy of hydrazine, which created an unrealistically strong connection between the gas phase thermochemistry and the calorimetric results defining the thermochemistry of liquid hydrazine was identified as the probable culprit. The new enthalpy of formation of gas-phase hydrazine, based on balancing all available knowledge, was determined to be 111.57more » ± 0.47 kJ/mol at 0 K (97.41 kJ/mol at 298.15 K). Close agreement was found between the ATcT (even excluding the latest theoretical result) and FPD enthalpies.« less

  14. Enthalpy of Formation of N2H4 (Hydrazine) Revisited.

    PubMed

    Feller, David; Bross, David H; Ruscic, Branko

    2017-08-17

    In order to address the accuracy of the long-standing experimental enthalpy of formation of gas-phase hydrazine, fully confirmed in earlier versions of Active Thermochemical Tables (ATcT), the provenance of that value is re-examined in light of new high-end calculations of the Feller-Peterson-Dixon (FPD) variety. An overly optimistic determination of the vaporization enthalpy of hydrazine, which created an unrealistically strong connection between the gas phase thermochemistry and the calorimetric results defining the thermochemistry of liquid hydrazine, was identified as the probable culprit. The new enthalpy of formation of gas-phase hydrazine, based on balancing all available knowledge, was determined to be 111.57 ± 0.47 kJ/mol at 0 K (97.42 ± 0.47 kJ/mol at 298.15 K). Close agreement was found between the ATcT (even excluding the latest theoretical result) and the FPD enthalpy.

  15. Ground Thermal Diffusivity Calculation by Direct Soil Temperature Measurement. Application to very Low Enthalpy Geothermal Energy Systems.

    PubMed

    Andújar Márquez, José Manuel; Martínez Bohórquez, Miguel Ángel; Gómez Melgar, Sergio

    2016-02-29

    This paper presents a methodology and instrumentation system for the indirect measurement of the thermal diffusivity of a soil at a given depth from measuring its temperature at that depth. The development has been carried out considering its application to the design and sizing of very low enthalpy geothermal energy (VLEGE) systems, but it can has many other applications, for example in construction, agriculture or biology. The methodology is simple and inexpensive because it can take advantage of the prescriptive geotechnical drilling prior to the construction of a house or building, to take at the same time temperature measurements that will allow get the actual temperature and ground thermal diffusivity to the depth of interest. The methodology and developed system have been tested and used in the design of a VLEGE facility for a chalet with basement at the outskirts of Huelva (a city in the southwest of Spain). Experimental results validate the proposed approach.

  16. Ground Thermal Diffusivity Calculation by Direct Soil Temperature Measurement. Application to very Low Enthalpy Geothermal Energy Systems

    PubMed Central

    Andújar Márquez, José Manuel; Martínez Bohórquez, Miguel Ángel; Gómez Melgar, Sergio

    2016-01-01

    This paper presents a methodology and instrumentation system for the indirect measurement of the thermal diffusivity of a soil at a given depth from measuring its temperature at that depth. The development has been carried out considering its application to the design and sizing of very low enthalpy geothermal energy (VLEGE) systems, but it can has many other applications, for example in construction, agriculture or biology. The methodology is simple and inexpensive because it can take advantage of the prescriptive geotechnical drilling prior to the construction of a house or building, to take at the same time temperature measurements that will allow get the actual temperature and ground thermal diffusivity to the depth of interest. The methodology and developed system have been tested and used in the design of a VLEGE facility for a chalet with basement at the outskirts of Huelva (a city in the southwest of Spain). Experimental results validate the proposed approach. PMID:26938534

  17. Studies of Mineral-Water Surfaces

    NASA Astrophysics Data System (ADS)

    Ross, Nancy L.; Spencer, Elinor C.; Levchenko, Andrey A.; Kolesnikov, Alexander I.; Wesolowski, David J.; Cole, David R.; Mamontov, Eugene; Vlcek, Lukas

    In this chapter we discuss the application of inelastic and quasielastic neutron scattering to the elucidation of the structure, energetics, and dynamics of water confined on the surfaces of mineral oxide nanoparticles. We begin by highlighting recent advancements in this active field of research before providing a brief review of the theory underpinning inelastic neutron scattering (INS) and quasielastic neutron scattering (QENS) techniques. We then discuss examples illustrating the use of neutron scattering methods for studying hydration layers that are an integral part of the nanoparticle structure. The first investigation of this kind, namely the INS analysis of hydrated ZrO2 nanoparticles, is described, as well as a later, complementary QENS study that allowed for the dynamics of diffusion of the water molecules within the hydration layer to be examined in detail. The diverse range of information available from INS experiments is illustrated by a recent study combining INS with calorimetric experiments that elucidated the thermodynamic properties of adsorbed water on anatase (TiO2) nanoparticles. To emphasize the importance of molecular dynamics (MD) simulations for deconvoluting complex QENS spectra, we describe both the MD and the QENS analysis of rutile (TiO2) and cassiterite (SnO2) nanoparticle systems and show that, when combined, data obtained by these two complementary methods can provide a complete description of the motion of the water molecules on the nanoparticle surface. We close with a glimpse into the future for this thriving field of research.

  18. Predicting the enthalpies of melting and vaporization for pure components

    NASA Astrophysics Data System (ADS)

    Esina, Z. N.; Korchuganova, M. R.

    2014-12-01

    A mathematical model of the melting and vaporization enthalpies of organic components based on the theory of thermodynamic similarity is proposed. In this empirical model, the phase transition enthalpy for the homological series of n-alkanes, carboxylic acids, n-alcohols, glycols, and glycol ethers is presented as a function of the molecular mass, the number of carbon atoms in a molecule, and the normal transition temperature. The model also uses a critical or triple point temperature. It is shown that the results from predicting the melting and vaporization enthalpies enable the calculation of binary phase diagrams.

  19. Thermodynamic data for modeling acid mine drainage problems: compilation and estimation of data for selected soluble iron-sulfate minerals

    USGS Publications Warehouse

    Hemingway, Bruch S.; Seal, Robert R.; Chou, I-Ming

    2002-01-01

    Enthalpy of formation, Gibbs energy of formation, and entropy values have been compiled from the literature for the hydrated ferrous sulfate minerals melanterite, rozenite, and szomolnokite, and a variety of other hydrated sulfate compounds. On the basis of this compilation, it appears that there is no evidence for an excess enthalpy of mixing for sulfate-H2O systems, except for the first H2O molecule of crystallization. The enthalpy and Gibbs energy of formation of each H2O molecule of crystallization, except the first, in the iron(II) sulfate - H2O system is -295.15 and -238.0 kJ?mol-1, respectively. The absence of an excess enthalpy of mixing is used as the basis for estimating thermodynamic values for a variety of ferrous, ferric, and mixed-valence sulfate salts of relevance to acid-mine drainage systems.

  20. From urban municipalities to polar bioremediation: the characterisation and contribution of biogenic minerals for water treatment.

    PubMed

    Freidman, Benjamin L; Northcott, Kathy A; Thiel, Peta; Gras, Sally L; Snape, Ian; Stevens, Geoff W; Mumford, Kathryn A

    2017-06-01

    Minerals of biological origin have shown significant potential for the separation of contaminants from water worldwide. This study details the contribution of biologically derived minerals to water treatment operations, with a focus on filtration media from urban municipalities and remote cold regions. The results support biofilm-embedded iron and manganese to be the building blocks of biogenic mineral development on activated carbon and nutrient-amended zeolites. The presence of similar iron and manganese oxidising bacterial species across all filter media supports the analogous morphologies of biogenic minerals between sites and suggests that biological water treatment processes may be feasible across a range of climates. This is the first time the stages of biogenic mineral formation have been aligned with comprehensive imaging of the biofilm community and bacterial identification; especially with respect to cold regions. Where biogenic mineral formation occurs on filter media, the potential exists for enhanced adsorption for a range of organic and inorganic contaminants and improved longevity of filter media beyond the adsorption or exchange capacities of the raw material.

  1. [Use of drinking mineral waters in children with bronchial asthma and associated biliary tract diseases].

    PubMed

    Efimenko, N V; Chalaia, E N; Demina, S V

    2008-01-01

    It is shown that supplementation of therapy of bronchial asthma in children by mineral water (Essentuki No 4) has marked beneficial effect on the functional activity of digestive organs and the respiratory system. It is recommended that drinking mineral waters be included in the course of the resort-and-spa treatment of such patients.

  2. Non-autoclaved aerated concrete with mineral additives

    NASA Astrophysics Data System (ADS)

    Il'ina, L. V.; Rakov, M. A.

    2016-01-01

    We investigated the effect of joint grinding of Portland cement clinker, silica and carbonate components and mineral additives to specific surface of 280 - 300 m2/kg on the properties (strength, average density and thermal conductivity) of non-autoclaved aerated concrete, and the porosity of the hardened cement paste produced from Portland cement clinker with mineral additives. The joint grinding of the Portland cement clinker with silica and carbonate components and mineral additives reduces the energy consumption of non-autoclaved aerated concrete production. The efficiency of mineral additives (diopside, wollastonite) is due to the closeness the composition, the type of chemical bonds, physical and chemical characteristics (specific enthalpy of formation, specific entropy) to anhydrous clinker minerals and their hydration products. Considering the influence of these additions on hydration of clinker minerals and formation of hardened cement paste structure, dispersed wollastonite and diopside should be used as mineral additives. The hardness and, consequently, the elastic modulus of diopside are higher than that of hardened cement paste. As a result, there is a redistribution of stresses in the hardened cement paste interporous partitions and hardening, both the partitions and aerated concrete on the whole. The mineral additives introduction allowed to obtain the non-autoclaved aerated concrete with average density 580 kg/m3, compressive strength of 3.3 MPa and thermal conductivity of 0.131 W/(m.°C).

  3. [One-time effects of drinking mineral water and tap water enriched with silver nanoparticles on the biochemical markers of liver condition and metabolic parameters in healthy rats].

    PubMed

    Efimenko, N V; Frolkov, V K; Kozlova, V V; Kaisinova, A S; Chalaya, E N

    2017-12-05

     The objective of the present research was to study the influence of tap water enriched with silver nanoparticles (NP) as well as that of «Krasnoarmeysky» and «Essentuki №17» mineral waters after their single administration through the oral gavage to the rats on the metabolism of carbohydrates and lipids, the biochemical markers of the liver condition, and the endocrine profile in the healthy animals.  The laboratory animals (130 male Wistar rats) were allocated to thirteen groups comprised of 10 rats each as follows: 1st group (n=10) intact animals, 2nd group (5 minutes after the administration of silver NP (n=10), 3rd group (15 minutes after the of silver NP), 4th group (60 minutes after the administration of silver NP), 5th group (n=10) (5 minutes after the introduction of the «Krasnoarmeysky» mineral water), 6th group (n=10) (15 min after the introduction of the «Krasnoarmeysky» mineral water), 7th group (n=10), (60 minutes after the introduction of the «Krasnoarmeysky» mineral water) 8th group (n=10) (5 minutes after the introduction of the «Essentuki № 17» mineral water), 9th group (n=10) (15 min after the introduction of the «Essentuki № 7» mineral water) , 10th group (n=10) (60 minutes after the introduction of the «Essentuki №17» mineral water), 11th group (n=10) (5 minutes after administration of tap water (control),12th group (n=10) (15 minutes after administration of tap water (control), and 13th (n=10) group 60 minutes after administration of tap water (control).  The study has demonstrated that the tap water enriched with silver nanoparticles similar to the mineral waters caused stress reactions that are inferior to those induced by «Essentuki №17» mineral water in terms of the magnitude; however, the effect provoked by the tap water was of longer duration. Moreover, the tap water enriched with silver nanoparticles stimulates prooxidant reactions, and inhibit the activity of antioxidant protection. Silver nanoparticles

  4. Behavior of the Enthalpy of Adsorption in Nanoporous Materials Close to Saturation Conditions

    PubMed Central

    2017-01-01

    Many important industrial separation processes based on adsorption operate close to saturation. In this regime, the underlying adsorption processes are mostly driven by entropic forces. At equilibrium, the entropy of adsorption is closely related to the enthalpy of adsorption. Thus, studying the behavior of the enthalpy of adsorption as a function of loading is fundamental to understanding separation processes. Unfortunately, close to saturation, the enthalpy of adsorption is hard to measure experimentally and hard to compute in simulations. In simulations, the enthalpy of adsorption is usually obtained from energy/particle fluctuations in the grand-canonical ensemble, but this methodology is hampered by vanishing insertions/deletions at high loading. To investigate the fundamental behavior of the enthalpy and entropy of adsorption at high loading, we develop a simplistic model of adsorption in a channel and show that at saturation the enthalpy of adsorption diverges to large positive values due to repulsive intermolecular interactions. However, there are many systems that can avoid repulsive intermolecular interactions and hence do not show this drastic increase in enthalpy of adsorption close to saturation. We find that the conventional grand-canonical Monte Carlo method is incapable of determining the enthalpy of adsorption from energy/particle fluctuations at high loading. Here, we show that by using the continuous fractional component Monte Carlo, the enthalpy of adsorption close to saturation conditions can be reliably obtained from the energy/particle fluctuations in the grand-canonical ensemble. The best method to study properties at saturation is the NVT energy (local-) slope methodology. PMID:28521093

  5. Determination of barium in natural waters by ICP-OES technique. Part II: Assessment of human exposure to barium in bottled mineral and spring waters produced in Poland.

    PubMed

    Garboś, Sławomir; Swiecicka, Dorota

    2013-01-01

    A method of the classification of natural mineral and spring waters and maximum admissible concentration (MAC) levels of metals present in such types of waters are regulated by Commission Directive 2003/40/EC, Directive 2009/54/EC of the European Parliament and of the Council and Ordinance of Minister of Health of 30 March 2011 on the natural mineral waters, spring waters and potable waters. MAC of barium in natural mineral and spring waters was set at 1.0 mg/l, while World Health Organization determined the Ba guideline value in water intended for human consumption at the level of 0.7 mg/l. The aims of the study were: the determination of barium in natural mineral and spring waters (carbonated, non-carbonated and medium-carbonated waters) produced and bottled on the area of Poland, and assessment of human exposure to this metal presents in the above-mentioned types of waters. The study concerning barium determinations in 23 types of bottled natural mineral waters and 15 types of bottled spring waters (bought in Polish retail outlets) was conducted in 2010. The analyses were performed by validated method of determination of barium in water based on inductively coupled plasma optical emission spectrometry, using modern internal quality control scheme. Concentrations of barium determined in natural mineral and spring waters were in the ranges from 0.0136 mg/l to 1.12 mg/l and from 0.0044 mg/l to 0.43 mg/l, respectively. Only in the single case of natural mineral water the concentration of barium (1.12 mg/l), exceeded above-mentioned MAC for this metal, which is obligatory in Poland and the European Union - 1.0 mg/l. The long-term monitoring of barium concentration in another natural mineral water (2006 - 2010), in which incidental exceeding MAC was observed in 2006, was conducted. All measured barium concentrations in this water were lower than 1.0 mg/l and therefore, it is possible to state that the proper method of mixing waters taken from six independent

  6. Increased fracture risk and low bone mineral density in patients with loeys-dietz syndrome.

    PubMed

    Tan, Eric W; Offoha, Roosevelt U; Oswald, Gretchen L; Skolasky, Richard L; Dewan, Ashvin K; Zhen, Gehua; Shapiro, Jay R; Dietz, Harry C; Cao, Xu; Sponseller, Paul D

    2013-08-01

    Loeys-Dietz syndrome is a recently recognized connective tissue disorder with widespread systemic involvement. Little is known about its skeletal phenotype. Our goal was to investigate the risk of fracture and incidence of low bone mineral density in patients with Loeys-Dietz syndrome. We performed a cross-sectional, descriptive, survey-based study with subsequent chart review from July 2011 to April 2012. Fifty-seven patients (26 men, 31 women) with Loeys-Dietz syndrome confirmed by genetic testing completed the survey (average age, 25.3 years; range, 0.9-79.6 years). There were a total of 51 fractures (33 patients): 35 fractures in the upper extremities, 14 in the lower extremities, and two in the spine. Fourteen patients (24.6%) reported two or more fractures. There was a 50% risk of fracture by age 14 years. The incidence of any fracture in this cohort was 3.86 per 100 person-years. Seventeen patients had dual-energy X-ray absorptiometry scans available for review, 11 (64.7%) of whom had at least one fracture. Thirteen included lumbar spine absorptiometry reports; eight (61.5%) indicated low or very low bone mineral density. In the left hip, ten of 14 participants (71.4%) had low or very low bone mineral density. In the left femoral neck, nine of 13 participants (69.2%) had low or very low bone mineral density. The lowest Z- and T-scores were not associated with an increased number of fractures. Patients with Loeys-Dietz syndrome have a high risk of fracture and a high incidence of low bone mineral density. Copyright © 2013 Wiley Periodicals, Inc.

  7. Using Enthalpy as a Prognostic Variable in Atmospheric Modelling with Variable Composition

    DTIC Science & Technology

    2016-04-14

    the first place. It then becomes clear that specific enthalpy provides a viable alternative to account for the effects of composi- tional changes on...forces. It is also assumed that external forces acting on a molecule are proportional to its mass, mi , as is the case with the gravity or Coriolis ...relative humidity and is introduced into Equation (11) to account for the effects of water vapour on the gas constant R and, consequently, on the

  8. Theoretical calculation of enthalpy of formation of multiconformational molecules: 1,2-ethanediol, propanediols, and glycerol

    NASA Astrophysics Data System (ADS)

    Dorofeeva, Olga V.; Suchkova, Taisiya A.

    2018-04-01

    The gas-phase enthalpies of formation of four molecules with high flexibility, which leads to the existence of a large number of low-energy conformers, were calculated with the G4 method to see whether the lowest energy conformer is sufficient to achieve high accuracy in the computed values. The calculated values were in good agreement with the experiment, whereas adding the correction for conformer distribution makes the agreement worse. The reason for this effect is a large anharmonicity of low-frequency torsional motions, which is ignored in the calculation of ZPVE and thermal enthalpy. It was shown that the approximate correction for anharmonicity estimated using a free rotor model is of very similar magnitude compared with the conformer correction but has the opposite sign, and thus almost fully compensates for it. Therefore, the common practice of adding only the conformer correction is not without problems.

  9. Mixing Enthalpies of TbBr3-MBr Liquid Mixtures

    NASA Astrophysics Data System (ADS)

    Rycerz, L.; Gaune-Escard, M.

    2001-12-01

    The molar enthalpies of mixing, Δmix Hm in the binary liquid systems TbBr3-MBr (M = Li, Na, K, Rb, Cs) have been m easured with a Calvet-type high-tem perature microcalorimeter over the entire composition range with an accuracy of about 6 %. Mixing of the two liquid components was achieved by using the "break-off am poule" technique. All the investigated systems show negative enthalpies of mixing with a minim um value of approxim ately -1.25, - 8 .3 , -17.0, - 2 0 . 0 and -22.5 kJ mol -1, for M = Li, Na, K, Rb and Cs, respectively. The mixing enthalpy in the TbBr3- LiBr system is positive in the TbBr3-rich region. For all the systems, the enthalpy minimum occurs at mole fraction xTbBr3 ≈ 0.3 - 0.4. The molar enthalpies of form ation Δ formHm (3MBr, TbBr3, 1) for M = Li, Na, K, Rb and Cs at 1113 K (arising from the reaction 3M Br(1) +TbBr3(1) = (3MBr, TbBr3) (1)) are found to be -4 .8 , -31.3, -63.3, -70.3 and -8 1 .2 kJ mol-1 , respectively. The leastsquares coefficients A, B, C, D and E in the equation λ (kJ mol-1) = A + B x + C x2 + Dx3 + Ex4, where A is an interaction param eter and x = xTbBr , are also reported.

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

    USGS Publications Warehouse

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

    1989-01-01

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

  11. Biological effects of drinking-water mineral composition on calcium balance and bone remodeling markers.

    PubMed

    Roux, S; Baudoin, C; Boute, D; Brazier, M; De La Guéronniere, V; De Vernejoul, M C

    2004-01-01

    To compare the effects of 2 drinking waters containing similar calcium (Ca) concentration in order to analyze the role of ions other than Ca on bone metabolism. These mineral drinking-waters differed by their mineral composition primarily concerning the concentration of bicarbonate (HCO3-), high in the HB, and sulfate, high in HS water. Of 60 included women, 39 completed the study. Patients were randomly assigned to an intake of 1 liter per day of mineral water HB or HS for 28 d, followed by cross-over to the alternative drinking-water for a further 28 d. At baseline and after each period of one month, Ca metabolism parameters, acid-base status, and bone remodeling markers were measured. Changes in Ca metabolism were significant in the HB group where the ionized Ca increased and the PTH decreased. Serum pH showed a similar increase whatever the used drinking water compared to baseline. In the HB group, significant increase in urine pH, and significant decrease in AT-HCO3- and NH4+ were observed. Bone resorption markers, urinary CTx/Cr, Pyr/Cr, and D-Pyr/Cr, significantly decreased in the HB group compared to baseline, and were not significantly modified in the HS group. These results showed a beneficial effect of the bicarbonaterich HB water on bone metabolism. This may account for a better bioavailability of the Ca, a greater alkalinization, and a larger decrease in PTH level secondary to a higher ionized Ca level. The higher content of silica in HB water may have also participated to the positive action on bone balance that was observed. In this short term study, these data underlined the potential role of the mineral drinking water composition on bone metabolism.

  12. Cl, P2O5, U and Br associated with mineral separates from a low and a high Ti mare basalt

    NASA Technical Reports Server (NTRS)

    Jovanovic, S.; Reed, G. W., Jr.

    1980-01-01

    Low Ti basalt 12040 and high Ti basalt 75055 have approximately the same Cl/P2O5 ratio; the Cl is that remaining after a hot water leach. Pyroxene, plagioclase and ilmenite minerals separated from the basalts also tend to have this same Cl/P2O5 ratio. This is evidence that these major minerals do not control the ratio since Cl and P would not be expected to partition to the same extent into each mineral. Olivine appears to be a special case. It is proposed that the grains measured contained inclusions with leachable and P2O5-related Cl. Dilute acid leaches of whole rock and separated minerals have the same or nearly the same Cl/P2O5 ratios as the residual samples. Apatite and whitlockite were probably the phases leached. They must be constituents of the mesostasis and are present as microminerals or coatings on major mineral grains. The acid leach results imply little or no partition of Cl and P2O5 into major minerals.

  13. Investigating ultra high-enthalpy geothermal systems: a collaborative initiative to promote scientific opportunities

    NASA Astrophysics Data System (ADS)

    Elders, W. A.; Nielson, D.; Schiffman, P.; Schriener, A., Jr.

    2014-12-01

    Scientists, engineers, and policy makers gathered at a workshop in the San Bernardino Mountains of southern California in October 2013 to discuss the science and technology involved in developing high-enthalpy geothermal fields. A typical high-enthalpy geothermal well between 2000 and 3000 m deep produces a mixture of hot water and steam at 200-300 °C that can be used to generate about 5-10 MWe of electric power. The theme of the workshop was to explore the feasibility and economic potential of increasing the power output of geothermal wells by an order of magnitude by drilling deeper to reach much higher pressures and temperatures. Development of higher enthalpy geothermal systems for power production has obvious advantages; specifically higher temperatures yield higher power outputs per well so that fewer wells are needed, leading to smaller environmental footprints for a given size of power plant. Plans for resource assessment and drilling in such higher enthalpy areas are already underway in Iceland, New Zealand, and Japan. There is considerable potential for similar developments in other countries that already have a large production of electricity from geothermal steam, such as Mexico, the Philippines, Indonesia, Italy, and the USA. However drilling deeper involves technical and economic challenges. One approach to mitigating the cost issue is to form a consortium of industry, government and academia to share the costs and broaden the scope of investigation. An excellent example of such collaboration is the Iceland Deep Drilling Project (IDDP), which is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs, and this approach could serve as model for future developments elsewhere. A planning committee was formed to explore creating a similar initiative in the USA.

  14. Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds. Sublimation, Vaporization and Fusion Enthalpies From 1880 to 2015. Part 1. C{sub 1} − C{sub 10}

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Acree, William; Chickos, James S.

    2016-09-15

    A compendium of phase change enthalpies published in 2010 is updated to include the period 1880–2015. Phase change enthalpies including fusion, vaporization, and sublimation enthalpies are included for organic, organometallic, and a few inorganic compounds. Part 1 of this compendium includes organic compounds from C{sub 1} to C{sub 10}. Part 2 of this compendium, to be published separately, will include organic and organometallic compounds from C{sub 11} to C{sub 192}. Sufficient data are presently available to permit thermodynamic cycles to be constructed as an independent means of evaluating the reliability of the data. Temperature adjustments of phase change enthalpies frommore » the temperature of measurement to the standard reference temperature, T = 298.15 K, and a protocol for doing so are briefly discussed.« less

  15. Kinetic Study of Denatonium Sorption to Smectite Clay Minerals

    PubMed Central

    Crosson, Garry S.; Sandmann, Emily

    2013-01-01

    Abstract The denatonium cation, as a benzoate salt, is the most bitter cation known to modern society and is frequently added to consumer products to reduce accidental and intentional consumption by humans and animals. Denatonium can enter the environment by accidental discharges, potentially rendering water supplies undrinkable. Interactions of denatonium with soil components (i.e., smectite minerals) ultimately control the environmental fate of denatonium, but the current literature is devoid of studies that evaluate denatonium sorption to smectite minerals. This study investigated the mechanism and kinetics of denatonium sorption to smectite clay minerals as a function of smectite type, temperature, pH and ionic strength. Uptake by synthetic mica montmorillonite (Syn-1), Wyoming montmorillonite (SWy-2), and Texas montmorillonite (STx-1b) at 305K was rapid, with equilibrium being reached within 2 min for all clays. Complete removal of denatonium was observed for STx-1b at pH 6.9, while partial removal was observed for Syn-1 and SWy-2. Kinetic behavior of SWy-2 and Syn-1 is consistent with a pseudo–second-order model at 305K. An activation energy of +25.9 kJ/mol was obtained for sorption to Syn-1 and was independent of temperature between 286K and 338K. Activation-free energy (ΔG*), activation enthalpy (ΔH*), and activation entropy (ΔS*) for Syn-1 were found to be +62.91 kJ/mol, +23.36 kJ/mol, and −0.130 kJ/(K·mol), respectively. Sorption capacities at pH 3.6, 6.9, and 8.2 were constant at 1.3×10−2 g denatonium/g clay; however, the kinetic rate constant increased by 56%, going from acidic to basic solution conditions. Distribution coefficients were negatively correlated with ionic strength, suggesting cation exchange. Collectively, results suggested that smectite minerals can serve as efficient sinks for denatonium cations. This is much-needed information for agencies developing regulations regarding denatonium usage and for water treatment

  16. X-ray photoelectron spectroscopic study of water adsorption on iron sulphide minerals

    NASA Astrophysics Data System (ADS)

    Knipe, S. W.; Mycroft, J. R.; Pratt, A. R.; Nesbitt, H. W.; Bancroff, G. M.

    1995-03-01

    Samples of natural pyrrhotite and pyrite were fractured within the analytical chamber of an X-ray photoelectron spectrometer. The pristine mineral surfaces were then exposed, in the absence of oxygen, to total doses of 100, 200, 400, 800, 1400, 28,000, and 300,000 Langmuirs (L) of D2O. X-ray photoelectron spectroscopic (XPS) analyses were performed between each water dose, to investigate the interaction of these iron sulphide surfaces with water vapour. Recorded Fe and S photoelectron spectra showed no evidence of oxidation products on either mineral, even at highest D2O doses, nor could an oxide oxygen signal be fitted in the spectra for either mineral. On pyrrhotite, the O 1s spectra are composed of contributions from dominantly hydroxyl (at 532.0 ± 0.2 eV ) and subordinate chemisorbed water (at 533.5 ± 0.2 eV) signals. The main O is peak on pyrite is also formed from hydroxyl (531.0 ± 0.3 eV) and adsorbed water/hydroxyl (at 532.3 eV) signals. However, some O is spectra recorded on pyrite have peaks at anomalously high binding energies (>535 eV ). The anomalous high binding energy species are attributed to electrically-isolated OH/H2O, as reported elsewhere, and to liquid-like water, which has not previously been described in the literature. Pyrrhotite and pyrite interact with water via fundamentally different processes. Pyrrhotite reaction involves the donation of electron charge through Fe vacancies, whereas the water species detected on pyrite interact with the Fe 3d (eg) molecular orbital, and it is suggested that hydrogen bonding with the disulphide moiety may be important.

  17. Osteoprotegerin autoantibodies do not predict low bone mineral density in middle-aged women.

    PubMed

    Vaziri-Sani, Fariba; Brundin, Charlotte; Agardh, Daniel

    2017-12-01

    Autoantibodies against osteoprotegerin (OPG) have been associated with osteoporosis. The aim was to develop an immunoassay for OPG autoantibodies and test their diagnostic usefulness of identifying women general population with low bone mineral density. Included were 698 women at mean age 55.1 years (range 50.4-60.6) randomly selected from the general population. Measurement of wrist bone mineral density (g/cm 2 ) was performed of the non-dominant wrist by dual-energy X-ray absorptiometry (DXA). A T-score < - 2.5 was defined as having a low bone mineral density. Measurements of OPG autoantibodies were carried by radiobinding assays. Cut-off levels for a positive value were determined from the deviation from normality in the distribution of 398 healthy blood donors representing the 99.7th percentile. Forty-five of the 698 (6.6%) women were IgG-OPG positive compared with 2 of 398 (0.5%) controls ( p  < 0.0001) and 35 of the 698 (5.0%) women had a T-score < - 2.5. There was no difference in bone mineral density between IgG-OPG positive (median 0.439 (range 0.315-0.547) g/cm 2 ) women and IgG-OPG negative (median 0.435 (range 0.176-0.652) g/cm 2 ) women ( p  = 0.3956). Furthermore, there was neither a correlation between IgG-OPG levels and bone mineral density (r s  = 0.1896; p  = 0.2068) nor T-score (r s  = 0.1889; p  = 0.2086). Diagnostic sensitivity and specificity of IgG-OPG for low bone mineral density were 5.7% and 92.9%, and positive and negative predictive values were 7.4% and 90.8%, respectively. Elevated OPG autoantibody levels do not predict low bone mineral density in middle-aged women selected from the general population.

  18. [The effect of mineral water on serotonin and insulin production (an experimental study)].

    PubMed

    Polushina, N D

    1998-01-01

    Radioimmunoassay (DRG kits) and orthotoluidine test were conducted to measure blood serotonin, insulin and glucose in 70 intact Wistar rat males before and after a course of drinking mineral water Essentuki 17 (MW). After the MW drinking course, a single dose of mineral water increases basal levels of serotonin and insulin, sensitivity of endocrine cells to MW. Serotonin and insulin rose maximally on minute 5 after the drink while in contrast to minute 15 and 30 before initiation of the MW drinking course. A direct correlation was found between blood concentrations of serotonin and insulin.

  19. In situ mid-infrared spectroscopic titration of forsterite with water in supercritical CO2: Dependence of mineral carbonation on quantitative water speciation

    NASA Astrophysics Data System (ADS)

    Loring, J. S.; Thompson, C. J.; Wang, Z.; Schaef, H. T.; Martin, P.; Qafoku, O.; Felmy, A. R.; Rosso, K. M.

    2011-12-01

    Geologic sequestration of carbon dioxide holds promise for helping mitigate CO2 emissions generated from the burning of fossil fuels. Supercritical CO2 (scCO2) plumes containing variable water concentrations (wet scCO2) will displace aqueous solution and dominate the pore space adjacent to caprocks. It is important to understand possible mineral reactions with wet scCO2 to better predict long-term caprock integrity. We introduce novel in situ instrumentation that enables quantitative titrations of reactant minerals with water in scCO2 at temperatures and pressures relevant to target geologic reservoirs. The system includes both transmission and attenuated total reflection mid-infrared optics. Transmission infrared spectroscopy is used to measure concentrations of water dissolved in the scCO2, adsorbed on mineral surfaces, and incorporated into precipitated carbonates. Single-reflection attenuated total reflection infrared spectroscopy is used to monitor water adsorption, mineral dissolution, and carbonate precipitation reactions. Results are presented for the infrared spectroscopic titration of forsterite (Mg2SiO4), a model divalent metal silicate, with water in scCO2 at 100 bar and at both 50 and 75°C. The spectral data demonstrate that the quantitative speciation of water as either dissolved or adsorbed is important for understanding the types, growth rates, and amounts of carbonate precipitates formed. Relationships between dissolved/adsorbed water, water concentrations, and the role of liquid-like adsorbed water are discussed. Our results unify previous in situ studies from our laboratory based on infrared spectroscopy, nuclear magnetic resonance spectroscopy and X-ray diffraction.

  20. Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 13. Mineral Microscopy and Chemistry of Mined and Unmined Porphyry Molybdenum Mineralization Along the Red River, New Mexico: Implications for Ground- and Surface-Water Quality

    USGS Publications Warehouse

    Plumlee, Geoff; Lowers, Heather; Ludington, Steve; Koenig, Alan; Briggs, Paul

    2005-01-01

    This report is one in a series presenting results of an interdisciplinary U.S. Geological Survey (USGS) study of ground-water quality in the lower Red River watershed prior to open-pit and underground molybdenite mining at Molycorp's Questa mine. The stretch of the Red River watershed that extends from just upstream of the town of Red River to just above the town of Questa includes several mineralized areas in addition to the one mined by Molycorp. Natural erosion and weathering of pyrite-rich rocks in the mineralized areas has created a series of erosional scars along this stretch of the Red River that contribute acidic waters, as well as mineralized alluvial material and sediments, to the river. The overall goal of the USGS study is to infer the pre-mining ground-water quality at the Molycorp mine site. An integrated geologic, hydrologic, and geochemical model for ground water in the mineralized but unmined Straight Creek drainage is being used as an analogue for the geologic, geochemical, and hydrologic conditions that influenced ground-water quality and quantity at the mine site prior to mining. This report summarizes results of reconnaissance mineralogical and chemical characterization studies of rock samples collected from the various scars and the Molycorp open pit, and of drill cuttings or drill core from bedrock beneath the scars and adjacent debris fans.

  1. Enthalpy of Vaporization by Gas Chromatography: A Physical Chemistry Experiment

    ERIC Educational Resources Information Center

    Ellison, Herbert R.

    2005-01-01

    An experiment is conducted to measure the enthalpy of vaporization of volatile compounds like methylene chloride, carbon tetrachloride, and others by using gas chromatography. This physical property was measured using a very tiny quantity of sample revealing that it is possible to measure the enthalpies of two or more compounds at the same time.

  2. Aerosol volatility and enthalpy of sublimation of carboxylic acids.

    PubMed

    Salo, Kent; Jonsson, Asa M; Andersson, Patrik U; Hallquist, Mattias

    2010-04-08

    The enthalpy of sublimation has been determined for nine carboxylic acids, two cyclic (pinonic and pinic acid) and seven straight-chain dicarboxylic acids (C(4) to C(10)). The enthalpy of sublimation was determined from volatility measurements of nano aerosol particles using a volatility tandem differential mobility analyzer (VTDMA) set-up. Compared to the previous use of a VTDMA, this novel method gives enthalpy of sublimation determined over an extended temperature range (DeltaT approximately 40 K). The determined enthalpy of sublimation for the straight-chain dicarboxylic acids ranged from 96 to 161 kJ mol(-1), and the calculated vapor pressures at 298 K are in the range of 10(-6)-10(-3) Pa. These values indicate that dicarboxylic acids can take part in gas-to-particle partitioning at ambient conditions and may contribute to atmospheric nucleation, even though homogeneous nucleation is unlikely. To obtain consistent results, some experimental complications in producing nanosized crystalline aerosol particles were addressed. It was demonstrated that pinonic acid "used as received" needed a further purification step before being suspended as a nanoparticle aerosol. Furthermore, it was noted from distinct differences in thermal properties that aerosols generated from pimelic acid solutions gave two types of particles. These two types were attributed to crystalline and amorphous configurations, and based on measured thermal properties, the enthalpy of vaporization was 127 kJ mol(-1) and that of sublimation was 161 kJ mol(-1). This paper describes a new method that is complementary to other similar methods and provides an extension of existing experimental data on physical properties of atmospherically relevant compounds.

  3. Mineral Selection for Multicomponent Equilibrium Geothermometry

    DOE PAGES

    Plamer, C. D.; Ohly, S. R.; Smith, R. W.; ...

    2015-04-01

    Multicomponent geothermometry requires knowledge of the mineral phases in the reservoir with which the geothermal fluids may be equilibrated. These minerals phases are most often alteration products rather than primary minerals. We have reviewed the literature on geothermal systems representing most major geologic environments typically associated with geothermal activity and identified potential alteration products in various environments. We have included this information in RTEst, a code we have developed to estimate reservoir conditions (temperature, CO 2 fugacity) from the geochemistry of near-surface geothermal waters. The information has been included in RTEst through the addition of filters that decrease the potentialmore » number of minerals from all possibilities based on the basis species to those that are more relevant to the particular conditions in which the user is interested. The three groups of filters include host rock type (tholeiitic, calc-alkaline, silicic, siliciclastic, carbonate), water type (acidic, neutral), and the temperature range over which the alteration minerals were formed (low, medium, high). The user-chosen mineral assemblage is checked to make sure that it does not violate the Gibbs phase rule. The user can select one of three mineral saturation weighting schemes that decrease the chance the optimization from being skewed by reaction stoichiometry or analytical uncertainty.« less

  4. Magnesium in tap and bottled mineral water in Spain and its contribution to nutritional recommendations.

    PubMed

    Maraver, Francisco; Vitoria, Isidro; Ferreira-Pêgo, Cíntia; Armijo, Francisco; Salas-Salvadó, Jordi

    2015-05-01

    An appropriate magnesium intake has proved to have beneficial effects on bone health, reduce insulin resistance and prevent atherosclerosis. To determine the concentration of magnesium in drinking water and bottled mineral water in Spain and assess its daily contribution to dietary recommendations. We used ion chromatography to analyse the magnesium concentrations of public drinking waters in a representative sample of 108 Spanish municipalities (supplying 21,290,707 potential individuals) and 109 natural mineral waters sold in Spain (97 Spanish and 12 imported). The water generally contained between 15 and 45 mg/L of magnesium, but in seven municipalities it contained over 45 mg/L. The average magnesium concentration of 97 brands of Spanish natural mineral water was 16.27 mg/L (range: 0.11-141.2 mg/L). Of these, 33 contained between 15 and 45 mg/L of magnesium and four contained over 45 mg/L. Of the 12 imported brands, 4 contained over 45 mg/L. Assuming water consumption is as recommended by the European Food Safety Agency, water containing 15 to 45 mg/L of magnesium provides between 9 and 76.5% of the recommended intake of magnesium for children aged one to thirteen, up to 25.7% in adolescents, between 7.5 and 25.7% for adults, and up to 27% for lactating women. Water with 60 mg/L of magnesium provides between 30 and 102% of the recommended dietary allowance, depending on the age of the individual. The consumption of public drinking water and natural mineral water in a third of Spanish cities can be regarded as an important supplementary source of magnesium. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  5. Proton affinity and enthalpy of formation of formaldehyde

    NASA Astrophysics Data System (ADS)

    Czakó, Gábor; Nagy, Balázs; Tasi, Gyula; Somogyi, Árpád; Šimunek, Ján; Noga, Jozef; Braams, Bastiaan J.; Bowman, Joel M.; Császár; , Attila G.

    The proton affinity and the enthalpy of formation of the prototypical carbonyl, formaldehyde, have been determined by the first-principles composite focal-point analysis (FPA) approach. The electronic structure computations employed the all-electron coupled-cluster method with up to single, double, triple, quadruple, and even pentuple excitations. In these computations the aug-cc-p(C)VXZ [X = 2(D), 3(T), 4(Q), 5, and 6] correlation-consistent Gaussian basis sets for C and O were used in conjunction with the corresponding aug-cc-pVXZ (X = 2-6) sets for H. The basis set limit values have been confirmed via explicitly correlated computations. Our FPA study supersedes previous computational work for the proton affinity and to some extent the enthalpy of formation of formaldehyde by accounting for (a) electron correlation beyond the "gold standard" CCSD(T) level; (b) the non-additivity of core electron correlation effects; (c) scalar relativity; (d) diagonal Born-Oppenheimer corrections computed at a correlated level; (e) anharmonicity of zero-point vibrational energies, based on global potential energy surfaces and variational vibrational computations; and (f) thermal corrections to enthalpies by direct summation over rovibrational energy levels. Our final proton affinities at 298.15 (0.0) K are ΔpaHo (H2CO) = 711.02 (704.98) ± 0.39 kJ mol-1. Our final enthalpies of formation at 298.15 (0.0) K are ΔfHo (H2CO) = -109.23 (-105.42) ± 0.33 kJ mol-1. The latter values are based on the enthalpy of the H2 + CO → H2CO reaction but supported by two further reaction schemes, H2O + C → H2CO and 2H + C + O → H2CO. These values, especially ΔpaHo (H2CO), have better accuracy and considerably lower uncertainty than the best previous recommendations and thus should be employed in future studies.

  6. Low temperature geothermal systems in carbonate-evaporitic rocks: Mineral equilibria assumptions and geothermometrical calculations. Insights from the Arnedillo thermal waters (Spain).

    PubMed

    Blasco, Mónica; Gimeno, María J; Auqué, Luis F

    2018-02-15

    Geothermometrical calculations in low-medium temperature geothermal systems hosted in carbonate-evaporitic rocks are complicated because 1) some of the classical chemical geothermometers are, usually, inadequate (since they were developed for higher temperature systems with different mineral-water equilibria at depth) and 2) the chemical geothermometers calibrated for these systems (based on the Ca and Mg or SO 4 and F contents) are not free of problems either. The case study of the Arnedillo thermal system, a carbonate-evaporitic system of low temperature, will be used to deal with these problems through the combination of several geothermometrical techniques (chemical and isotopic geothermometers and geochemical modelling). The reservoir temperature of the Arnedillo geothermal system has been established to be in the range of 87±13°C being the waters in equilibrium with respect to calcite, dolomite, anhydrite, quartz, albite, K-feldspar and other aluminosilicates. Anhydrite and quartz equilibria are highly reliable to stablish the reservoir temperature. Additionally, the anhydrite equilibrium explains the coherent results obtained with the δ 18 O anhydrite - water geothermometer. The equilibrium with respect to feldspars and other aluminosilicates is unusual in carbonate-evaporitic systems and it is probably related to the presence of detrital material in the aquifer. The identification of the expected equilibria with calcite and dolomite presents an interesting problem associated to dolomite. Variable order degrees of dolomite can be found in natural systems and this fact affects the associated equilibrium temperature in the geothermometrical modelling and also the results from the Ca-Mg geothermometer. To avoid this uncertainty, the order degree of the dolomite present in the Arnedillo reservoir has been determined and the results indicate 18.4% of ordered dolomite and 81.6% of disordered dolomite. Overall, the results suggest that this multi

  7. Mineralogy and geochemistry of efflorescent minerals on mine tailings and their potential impact on water chemistry.

    PubMed

    Grover, B P C; Johnson, R H; Billing, D G; Weiersbye, I M G; Tutu, H

    2016-04-01

    In the gold mining Witwatersrand Basin of South Africa, efflorescent mineral crusts are a common occurrence on and nearby tailings dumps during the dry season. The crusts are readily soluble and generate acidic, metal- and sulphate-rich solutions on dissolution. In this study, the metal content of efflorescent crusts at an abandoned gold mine tailings dump was used to characterise surface and groundwater discharges from the site. Geochemical modelling of the pH of the solution resulting from the dissolution of the crusts was used to better understand the crusts' potential impact on water chemistry. The study involved two approaches: (i) conducting leaching experiments on oxidised and unoxidised tailings using artificial rainwater and dilute sulphuric acid and correlating the composition of crusts to these leachates and (ii) modelling the dissolution of the crusts in order to gain insight into their mineralogy and their potential impact on receiving waters. The findings suggested that there were two chemically distinct discharges from the site, namely an aluminium- and magnesium-rich surface water plume and an iron-rich groundwater plume. The first plume was observed to originate from the oxidised tailings following leaching with rainwater while the second plume originated from the underlying unoxidised tailings with leaching by sulphuric acid. Both groups of minerals forming from the respective plumes were found to significantly lower the pH of the receiving water with simulations of their dissolution found to be within 0.2 pH units of experimental values. It was observed that metals in a low abundance within the crust (for example, iron) had a stronger influence on the pH of the resulting solutions than metals in a greater abundance (aluminium or magnesium). Techniques such as powder X-ray diffraction (PXRD) and in situ mineral determination techniques such as remote sensing can effectively determine the dominant mineralogy. However, the minerals or metals

  8. Modelling the complete operation of a free-piston shock tunnel for a low enthalpy condition

    NASA Astrophysics Data System (ADS)

    McGilvray, M.; Dann, A. G.; Jacobs, P. A.

    2013-07-01

    Only a limited number of free-stream flow properties can be measured in hypersonic impulse facilities at the nozzle exit. This poses challenges for experimenters when subsequently analysing experimental data obtained from these facilities. Typically in a reflected shock tunnel, a simple analysis that requires small amounts of computational resources is used to calculate quasi-steady gas properties. This simple analysis requires initial fill conditions and experimental measurements in analytical calculations of each major flow process, using forward coupling with minor corrections to include processes that are not directly modeled. However, this simplistic approach leads to an unknown level of discrepancy to the true flow properties. To explore the simple modelling techniques accuracy, this paper details the use of transient one and two-dimensional numerical simulations of a complete facility to obtain more refined free-stream flow properties from a free-piston reflected shock tunnel operating at low-enthalpy conditions. These calculations were verified by comparison to experimental data obtained from the facility. For the condition and facility investigated, the test conditions at nozzle exit produced with the simple modelling technique agree with the time and space averaged results from the complete facility calculations to within the accuracy of the experimental measurements.

  9. Influences of pH and CO2 on the formation of Metasilicate mineral water in Changbai Mountain, Northeast China

    NASA Astrophysics Data System (ADS)

    Yan, Baizhong; Xiao, Changlai; Liang, Xiujuan; Wu, Shili

    2017-07-01

    Mineral dissolution reactions actively participate in controlling the composition of mineral water. In this study, water soluble, acidic-alkaline and carbonated solution experiments were designed, and mineral reaction mechanisms were researched using chemical kinetics and the minimum free-energy method. The results showed that the release of metasilicate was controlled by pH, CO2, and rock characteristics. In the water soluble experiment, the release process of metasilicate in powdered rocks reached equilibrium after 40 days, while metasilicate in solid rocks took 170 days. The release process of metasilicate in solid rocks satisfied an asymptotic model, while in powdered rocks it accorded with the Stanford reaction kinetic model. In the acidic-alkaline experiment, metasilicate was released earlier under acidic conditions (2.46 < pH < 7) than under alkaline conditions (7 < pH < 10.61). The release process of metasilicate under acidic conditions reached equilibrium in 40 days, compared with 60 days for alkaline conditions. The addition of CO2 to the water solution was beneficial to the formation of metasilicate. Under neutral pH conditions, the reaction barely occurred. Under alkaline conditions, metasilicate was produced by the hydrolysis of metasilicate minerals. Under acidic and additional CO2 conditions, metasilicate formation was mainly via the reaction of H+, CO2, and metasilicate minerals. From these results, we concluded that the metasilicate mineral water from the Changbai Mountains, Jingyu County, is generated by a combination of the hydrolysis of metasilicate minerals and the reaction of H+, CO2, and metasilicate minerals. These results can contribute to a better development and protection of the mineral water resources in the Changbai Mountains.

  10. Geochemical Composition of Surface Water in the Mineralized Lom Basin, East Cameroon: Natural and Anthropogenic Sources.

    NASA Astrophysics Data System (ADS)

    Mimba, M. E.; Ohba, T.; Nguemhe Fils, S. C.; Wirmvem, M. J.

    2016-12-01

    Thousands of people in East Cameroon depend on surface water for consumption and domestic purposes. The Lom basin, north of the region, is heavily mineralized especially in gold owing to its regional geological setting. Although research has been done regarding the rock type, age, formation history and reconnaissance gold surveys, surface water investigation in the area has received limited attention. Thus, this study appraises the first regional hydrogeochemical program for environmental assessment of the mineralized Lom basin. Fifty-two representative stream water samples were collected under base flow conditions and analysed for major cations (Ca2+, Mg2+, Na+, K+ ), major anions (HCO3-, F-, Cl-, NO2-, NO3-, Br-, PO43-, SO42- ) and stable isotopes (δD and δ18O). Calcium and HCO3- were the dominant ions. The chemical facies were CaHCO3 and NaHCO3 indicating surface water draining igneous/metamorphic rocks in hot and humid equatorial climate, resulting in the discordant dissolution of primary silicate minerals. From the isotopic evaluation, the stream water is of meteoric origin, shows negligible evaporation effect and has a common recharge source. The major ion geochemistry demonstrated the potential to discriminate between natural and anthropogenic origins. Distribution trends of Ca2+, Mg2+, Na+, K+, HCO3- and SO42- showed a correlation with the lithology and the occurrence of sulphide minerals associated with hydrothermal gold mineralization in the area. The distribution patterns of NO3- and Cl- reflect pollution from settlement. Overall, the chemistry of stream water in the Lom basin is mainly controlled by rock weathering compared to anthropogenic influence. Surface water quality is easily influenced by anthropogenic activities, and stream sediment collects effectively trace metals resulting from such activities. Hence, geochemical mapping incorporating stream water and stream sediment is of considerable value in future investigations within the Lom basin.

  11. Naturally acidic surface and ground waters draining porphyry-related mineralized areas of the Southern Rocky Mountains, Colorado and New Mexico

    USGS Publications Warehouse

    Verplanck, P.L.; Nordstrom, D. Kirk; Bove, D.J.; Plumlee, G.S.; Runkel, R.L.

    2009-01-01

    Acidic, metal-rich waters produced by the oxidative weathering and resulting leaching of major and trace elements from pyritic rocks can adversely affect water quality in receiving streams and riparian ecosystems. Five study areas in the southern Rocky Mountains with naturally acidic waters associated with porphyry mineralization were studied to document variations in water chemistry and processes that control the chemical variations. Study areas include the Upper Animas River watershed, East Alpine Gulch, Mount Emmons, and Handcart Gulch in Colorado and the Red River in New Mexico. Although host-rock lithologies in all these areas range from Precambrian gneisses to Cretaceous sedimentary units to Tertiary volcanic complexes, the mineralization is Tertiary in age and associated with intermediate to felsic composition, porphyritic plutons. Pyrite is ubiquitous, ranging from ???1 to >5 vol.%. Springs and headwater streams have pH values as low as 2.6, SO4 up to 3700 mg/L and high dissolved metal concentrations (for example: Fe up to 400 mg/L; Cu up to 3.5 mg/L; and Zn up to 14.4 mg/L). Intensity of hydrothermal alteration and presence of sulfides are the primary controls of water chemistry of these naturally acidic waters. Subbasins underlain by intensely hydrothermally altered lithologies are poorly vegetated and quite susceptible to storm-induced surface runoff. Within the Red River study area, results from a storm runoff study documented downstream changes in river chemistry: pH decreased from 7.80 to 4.83, alkalinity decreased from 49.4 to <1 mg/L, SO4 increased from 162 to 314 mg/L, dissolved Fe increased from to 0.011 to 0.596 mg/L, and dissolved Zn increased from 0.056 to 0.607 mg/L. Compared to mine drainage in the same study areas, the chemistry of naturally acidic waters tends to overlap but not reach the extreme concentrations of metals and acidity as some mine waters. The chemistry of waters draining these mineralized but unmined areas can be used to

  12. Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.

    PubMed

    Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

    2012-04-12

    Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids.

  13. Risk factors for low bone mineral density in children and adolescents with inflammatory bowel disease.

    PubMed

    Lopes, Letícia Helena Caldas; Sdepanian, Vera Lucia; Szejnfeld, Vera Lúcia; de Morais, Mauro Batista; Fagundes-Neto, Ulysses

    2008-10-01

    To evaluate bone mineral density of the lumbar spine in children and adolescents with inflammatory bowel disease, and to identify the clinical risk factors associated with low bone mineral density. Bone mineral density of the lumbar spine was evaluated using dual-energy X-ray absorptiometry (DXA) in 40 patients with inflammatory bowel disease. Patients were 11.8 (SD = 4.1) years old and most of them were male (52.5%). Multiple linear regression analysis was performed to identify potential associations between bone mineral density Z-score and age, height-for-age Z-score, BMI Z-score, cumulative corticosteroid dose in milligrams and in milligrams per kilogram, disease duration, number of relapses, and calcium intake according to the dietary reference intake. Low bone mineral density (Z-score bellow -2) was observed in 25% of patients. Patients with Crohn's disease and ulcerative colitis had equivalent prevalence of low bone mineral density. Multiple linear regression models demonstrated that height-for-age Z-score, BMI Z-score, and cumulative corticosteroid dose in mg had independent effects on BMD, respectively, beta = 0.492 (P = 0.000), beta = 0.460 (P = 0.001), beta = - 0.014 (P = 0.000), and these effects remained significant after adjustments for disease duration, respectively, beta = 0.489 (P = 0.013), beta = 0.467 (P = 0.001), and beta = - 0.005 (P = 0.015). The model accounted for 54.6% of the variability of the BMD Z-score (adjusted R2 = 0.546). The prevalence of low bone mineral density in children and adolescents with inflammatory bowel disease is considerably high and independent risk factors associated with bone mineral density are corticosteroid cumulative dose in milligrams, height-for-age Z-score, and BMI Z-score.

  14. Concentrations of selected trace elements in mineral and spring bottled waters on the Serbian market.

    PubMed

    Ristić, M; Popović, I; Pocajt, V; Antanasijević, D; Perić-Grujić, A

    2011-01-01

    Eight selected trace elements, which are generally included in regulations, were analyzed in 23 types of bottled waters. Ten mineral and seven spring bottled waters were from the Serbian market and six mineral bottled waters were obtained in different EU countries. For the purpose of comparison, selected tap waters were also analyzed. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the analysis of trace elements (arsenic, cadmium, copper, manganese, nickel, lead and antimony). Results were compared with the Serbian regulations for bottled water, EU regulations and guideline values set by the World Health Organization for drinking water. With few exceptions, the trace element levels of most bottled waters were below the guideline values. However, a higher content of antimony was observed in waters from polyethylene terephthalate (PET) containers, indicating a potential leaching of this element from the plastic packaging.

  15. Kinetic theory of oxygen isotopic exchange between minerals and water

    USGS Publications Warehouse

    Criss, R.E.; Gregory, R.T.; Taylor, H.P.

    1987-01-01

    Kinetic and mass conservation equations are used to describe oxygen isotopic exchange between minerals and water in "closed" and open hydrothermal systems. In cases where n coexisting mineral phases having different reaction rates are present, the exchange process is described by a system of n + 1 simultaneous differential equations consisting of n pseudo first-order rate equations and a conservation of mass equation. The simultaneous solutions to these equations generate curved exchange trajectories on ??-?? plots. Families of such trajectories generated under conditions allowing for different fluid mole fractions, different fluid isotopic compositions, or different fluid flow rates are connected by positive-sloped isochronous lines. These isochrons reproduce the effects observed in hydrothermally exchanged mineral pairs including 1) steep positive slopes, 2) common reversals in the measured fractionation factors (??), and 3) measured fractionations that are highly variable over short distances where no thermal gradient can be geologically demonstrated. ?? 1987.

  16. Cavitation pitting and erosion of Al 6061-T6 in mineral oil and water

    NASA Technical Reports Server (NTRS)

    Rao, B. C. S.; Buckley, D. H.

    1983-01-01

    The authors are currently carrying out a study of the cavitation erosion of different bearing metals and alloys in mineral oils were studied. The variations of weight loss, the pit diameter and depth due to cavitation erosion on Al 6061-T6 in mineral oil and water are presented.

  17. Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11-C192

    NASA Astrophysics Data System (ADS)

    Acree, William; Chickos, James S.

    2017-03-01

    The second part of this compendium concludes with a collection of phase change enthalpies of organic molecules inclusive of C11-C192 reported over the period 1880-2015. Also included are phase change enthalpies including fusion, vaporization, and sublimation enthalpies for organometallic, ionic liquids, and a few inorganic compounds. Paper I of this compendium, published separately, includes organic compounds from C1 to C10 and describes a group additivity method for evaluating solid, liquid, and gas phase heat capacities as well as temperature adjustments of phase changes. Paper II of this compendium also includes an updated version of a group additivity method for evaluating total phase change entropies which together with the fusion temperature can be useful in estimating total phase change enthalpies. Other uses include application in identifying potential substances that either form liquid or plastic crystals or exhibit additional phase changes such as undetected solid-solid transitions or behave anisotropically in the liquid state.

  18. Effects of natural mineral-rich water consumption on the expression of sirtuin 1 and angiogenic factors in the erectile tissue of rats with fructose-induced metabolic syndrome

    PubMed Central

    Pereira, Cidália D; Severo, Milton; Rafael, Luísa; Martins, Maria João; Neves, Delminda

    2014-01-01

    Consuming a high-fructose diet induces metabolic syndrome (MS)-like features, including endothelial dysfunction. Erectile dysfunction is an early manifestation of endothelial dysfunction and systemic vascular disease. Because mineral deficiency intensifies the deleterious effects of fructose consumption and mineral ingestion is protective against MS, we aimed to characterize the effects of 8 weeks of natural mineral-rich water consumption on the structural organization and expression of vascular growth factors and receptors on the corpus cavernosum (CC) in 10% fructose-fed Sprague-Dawley rats (FRUCT). Differences were not observed in the organization of the CC either on the expression of vascular endothelial growth factor (VEGF) or the components of the angiopoietins/Tie2 system. However, opposing expression patterns were observed for VEGF receptors (an increase and a decrease for VEGFR1 and VEGFR2, respectively) in FRUCT animals, with these patterns being strengthened by mineral-rich water ingestion. Mineral-rich water ingestion (FRUCTMIN) increased the proportion of smooth muscle cells compared with FRUCT rats and induced an upregulatory tendency of sirtuin 1 expression compared with the control and FRUCT groups. Western blot results were consistent with the dual immunofluorescence evaluation. Plasma oxidized low-density lipoprotein and plasma testosterone levels were similar among the experimental groups, although a tendency for an increase in the former was observed in the FRUCTMIN group. The mineral-rich water-treated rats presented changes similar to those observed in rats treated with MS-protective polyphenol-rich beverages or subjected to energy restriction, which led us to hypothesize that the effects of mineral-rich water consumption may be more vast than those directly observed in this study. PMID:24625878

  19. Self-assembled biomimetic superhydrophobic CaCO3 coating inspired from fouling mineralization in geothermal water.

    PubMed

    Wang, Gong G; Zhu, Li Q; Liu, Hui C; Li, Wei P

    2011-10-18

    Inspired from fouling self-mineralization in geothermal water, a novel biomimetic cactuslike CaCO(3) coating with superhydrophobic features is reported in this letter. The structure, morphologies, and phases of the CaCO(3) coating were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, and infrared spectrophotometry. After prenucleation treatment, a continuous cactuslike CaCO(3) coating with hierarchical nano- and microstructures was self-assembled on stainless steel surfaces after immersion in simulated geothermal water at 50 °C for 48 h. After being modified with a low-surface-energy monolayer of sodium stearate, the as-prepared coating exhibited superhydrophobic properties with a water contact angle of 158.9° and a sliding angle of 2°. Therefore, this work might open up a new application field of geothermal resources and provide insight into designing multidimensional structures with functional applications, including superhydrophobic surfaces. © 2011 American Chemical Society

  20. A correct enthalpy relationship as thermal comfort index for livestock.

    PubMed

    Rodrigues, Valéria Cristina; da Silva, Iran José Oliveira; Vieira, Frederico Márcio Corrêa; Nascimento, Sheila Tavares

    2011-05-01

    Researchers working with thermal comfort have been using enthalpy to measure thermal energy inside rural facilities, establishing indicator values for many situations of thermal comfort and heat stress. This variable turned out to be helpful in analyzing thermal exchange in livestock systems. The animals are exposed to an environment which is decisive for the thermoregulatory process, and, consequently, the reactions reflect states of thermal comfort or heat stress, the last being responsable for problems of sanity, behavior and productivity. There are researchers using enthalpy as a qualitative indicator of thermal environment of livestock such as poultry, cattle and hogs in tropical regions. This preliminary work intends to check different enthalpy equations using information from classical thermodynamics, and proposes a direct equation as thermal comfort index for livestock systems.

  1. Prediction of solvation enthalpy of gaseous organic compounds in propanol

    NASA Astrophysics Data System (ADS)

    Golmohammadi, Hassan; Dashtbozorgi, Zahra

    2016-09-01

    The purpose of this paper is to present a novel way for developing quantitative structure-property relationship (QSPR) models to predict the gas-to-propanol solvation enthalpy (Δ H solv) of 95 organic compounds. Different kinds of descriptors were calculated for each compound using the Dragon software package. The variable selection technique of replacement method (RM) was employed to select the optimal subset of solute descriptors. Our investigation reveals that the dependence of physical chemistry properties of solution on solvation enthalpy is nonlinear and that the RM method is unable to model the solvation enthalpy accurately. The results established that the calculated Δ H solv values by SVM were in good agreement with the experimental ones, and the performances of the SVM models were superior to those obtained by RM model.

  2. [The mechanisms underlying the therapeutic effects of reflexotherapy and drinking mineral waters in the patients presenting with metabolic syndrome].

    PubMed

    Zhernov, V A; Frolkov, V K; Zubarkina, M M

    Both acupuncture and drinking mineral water can influence the metabolism of carbohydrates and lipids as well as their hormonal regulation, but the possibility of the application of these therapeutic factors for the correction of insulin resistance has not been studied in the patients presenting with metabolic syndrome. The objective of the present study was to evaluate the effects produced by the intake of drinking mineral water and acupuncture on the various parameters characterizing the patients suffering from metabolic syndrome in combination with altered insulin resistance. Ninety patients with this condition included in the study underwent the analysis of their the blood pressure, body mass index, blood glucose and lipid levels, insulin and cortisol secretion. We undertook the analysis of the effects of the single and repeated intakes of Essentuki No 17 mineral water included in the combined treatment of the patients with metabolic syndrome and revealed many common responses of the organism to its therapeutic action. Specifically, the stress-type reactions suggested the initiation of the adaptive processes in the system of hormonal regulation of carbohydrate and lipid metabolism. Simultaneously, the manifestations of insulin resistance became less pronounced indicating that both acupuncture and drinking mineral water suppressed the action of the main pathogenic mechanisms underlying the development of metabolic syndrome. Moreover, it was shown that acupuncture had a stronger hypotensive effect in the combination with the decrease of the overproduction of cortisol whereas the intake of the mineral water had a greater metabolic potential and contributed to the intensification of the basal secretion of glucocorticoids. Both reflexotherapy and drinking mineral water have a well apparent effect on the pathogenetic reactions of the metabolic syndrome and therefore can be used in addition to the standard therapy to activate the non-specific, phylogenetically

  3. Recent spectroscopic findings concerning clay/water interactions at low humidity: Possible applications to models of Martian surface reactivity

    NASA Technical Reports Server (NTRS)

    Coyne, L.; Bishop, J.; Howard, L.; Scattergood, T. W.

    1991-01-01

    A feasibility study assessing the utility of the adaptation of near infrared correlation spectroscopy to quantifying iron and adsorbed water in some clay-based Mars soil analog materials (MarSAM's). The work was intended to constitute Phase 1 of an approach to identifying optical analytical wavelength regions, not only for important mineral classes, but for chemically active centers within them. Many of these centers are common to unrelated mineral classes and of disproportionate influence relative to the mineral structure as a whole in determining the surface reactivity of mineral surfaces. We previously reported linearity between reflectance and total iron and total moisture over a large range of both key variables. We also discovered interesting relationships between the intensity of iron bands and the relative humidity of the systems. These relationships were confirmed. We also show that, in the low humidity range, reflectance is linearly dependent on a different kind of water from that best representing the full humidity range (the kind of water associated, in clays, with surface acidity). These relationships and the sensitivity and capability of quantitation of near infrared data indicate high promise with the production of reactive surface intermediates of products of surface reactions.

  4. Development of lucerne (Medicago sativa L.) treated with mineral fertilizer and manure at optimal and water deficit conditions.

    PubMed

    Vasileva, V; Kostov, O; Vasilev, E

    2006-01-01

    A study on the effect of different rates of mineral fertilizer and manure on yield parameters of lucerne under optimal and water deficit conditions was carried out. Leached chernozem soil and lucerne cultivar Victoria were used. The soil was treated with ammonium nitrate and fully matured cattle manure. The plants were grown under optimum moisture content of 80% and 40% of field capacity. The water deficit stress decreased top and root biomass by 11-75% and 3-29% at mineral and organic fertilization, respectively. The applied mineral and organic N strongly depressed nodules development. Both mineral fertilizer and organic manure at dose of 210 mg N kg(-1) soil completely inhibited the appearance of nodules. Next to nitrogen, water deficit stress further inhibited the development of nodules. Nitrogen fertilization increased seed productivity in the two experimental moisture conditions. The water deficit stress decreased seed productivity by 18 to 33% as compared to optimum conditions. The plant treatments with manure were much more resistant to water deficit and recovering ability of plants was faster as compared to treatments with mineral fertilizer. The application of manure stimulates development of drought-stress tolerance in lucerne. However, the results obtained can be considered for the soil type and experimental conditions used.

  5. Discrimination of fish oil and mineral oil slicks on sea water

    NASA Technical Reports Server (NTRS)

    Mac Dowall, J.

    1969-01-01

    Fish oil and mineral oil slicks on sea water can be discriminated by their different spreading characteristics and by their reflectivities and color variations over a range of wavelengths. Reflectivities of oil and oil films are determined using a duel beam reflectance apparatus.

  6. Determining the Enthalpy of Vaporization of Salt Solutions Using the Cooling Effect of a Bubble Column Evaporator

    ERIC Educational Resources Information Center

    Fan, Chao; Pashley, Richard M.

    2016-01-01

    The enthalpy of vaporization (?H[subscript vap]) of salt solutions is not easily measured, as a certain quantity of pure water has to be evaporated from a solution, at constant composition, and at a fixed temperature and pressure; then the corresponding heat input has to be measured. However, a simple bubble column evaporator (BCE) was used as a…

  7. The impact of post-exercise hydration with deep-ocean mineral water on rehydration and exercise performance.

    PubMed

    Keen, Douglas A; Constantopoulos, Eleni; Konhilas, John P

    2016-01-01

    Dehydration caused by prolonged exercise impairs thermoregulation, endurance and exercise performance. Evidence from animal and human studies validates the potential of desalinated deep-ocean mineral water to positively impact physiological and pathophysiological conditions. Here, we hypothesize that deep-ocean mineral water drawn from a depth of 915 m off the Kona, HI coast enhances recovery of hydration and exercise performance following a dehydrating exercise protocol compared to mountain spring water and a carbohydrate-based sports drink. Subjects (n = 8) were exposed to an exercise-dehydration protocol (stationary biking) under warm conditions (30 °C) to achieve a body mass loss of 3 % (93.4 ± 21.7 total exercise time). During the post-exercise recovery period, subjects received deep-ocean mineral water (Kona), mountain spring water (Spring) or a carbohydrate-based sports drink (Sports) at a volume (in L) equivalent to body mass loss (in Kg). Salivary samples were collected at regular intervals during exercise and post-exercise rehydration. Additionally, each participant performed peak torque knee extension as a measure of lower body muscle performance. Subjects who received Kona during the rehydrating period showed a significantly more rapid return to pre-exercise (baseline) hydration state, measured as the rate of decline in peak to baseline salivary osmolality, compared to Sports and Spring groups. In addition, subjects demonstrated significantly improved recovery of lower body muscle performance following rehydration with Kona versus Sports or Spring groups. Deep-ocean mineral water shows promise as an optimal rehydrating source over spring water and/or sports drink.

  8. Concentration of Ra-226 in Malaysian Drinking and Bottled Mineral Water

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Amin, Y. B. Mohd; Jemangin, M. H.; Mahat, R. H.

    2010-07-07

    The concentration of the radionuclide {sup 226}Ra was determined in the drinking water which was taken from various sources. It was found that the concentration varies from non-detectable (ND) to highest value of 0.30 Bq per liter. The concentration was found to be high in mineral water as compare with surface water such as domestic pipe water. Some of these values have exceeded the EPA (Environmental Protection Agency) of America regulations. The activity concentrations obtained are compared with data from other countries. The estimated annual effective doses from drinking the water are determined. The values obtained range from 0.02 mSvmore » to about 0.06 mSv per year.« less

  9. Split-step eigenvector-following technique for exploring enthalpy landscapes at absolute zero.

    PubMed

    Mauro, John C; Loucks, Roger J; Balakrishnan, Jitendra

    2006-03-16

    The mapping of enthalpy landscapes is complicated by the coupling of particle position and volume coordinates. To address this issue, we have developed a new split-step eigenvector-following technique for locating minima and transition points in an enthalpy landscape at absolute zero. Each iteration is split into two steps in order to independently vary system volume and relative atomic coordinates. A separate Lagrange multiplier is used for each eigendirection in order to provide maximum flexibility in determining step sizes. This technique will be useful for mapping the enthalpy landscapes of bulk systems such as supercooled liquids and glasses.

  10. Fluoride content of infant formulas prepared with deionized, bottled mineral and fluoridated drinking water.

    PubMed

    Buzalaf, M A; Granjeiro, J M; Damante, C A; de Ornelas, F

    2001-01-01

    Usually infant milk formula is the major source of fluoride in infancy. Fluoride concentrations in ten samples of powdered milk formulas, prepared with deionized, bottled mineral, and fluoridated drinking water were determined after HMDS-facilitated diffusion, using a fluoride ion specific electrode(Orion 9609). Fluoride concentrations ranged from 0.01 to 0.75 ppm; from 0.02 to 1.37 ppm and from 0.91 to 1.65 ppm for formulas prepared with deionized, bottled mineral (0.02 to 0.69 ppm F) and fluorinated drinking water (0.9 ppm F), respectively. Possible fluoride ingestion per Kg body mass ws estimated. With deionized water, only the soy-based- formulas should provide a daily fluoride intake of above the suggested threshold for fluorosis. With water containing 0.9 ppm F, however, all of them would provide it. Hence, to limit fluoride intakes to amounts <0.1 mg/kg/day, it is necessary to avoid use fo fluoridated water (around 1 ppm) to dilute powdered infant formulas.

  11. Mineral textures in Serpentine-hosted Alkaline Springs from the Oman ophiolite

    NASA Astrophysics Data System (ADS)

    Giampouras, Manolis; Garcia-Ruiz, Juan Manuel; Bach, Wolfgang; Garrido, Carlos J.; Los, Karin; Fussmann, Dario; Monien, Monien

    2017-04-01

    Meteoric water infiltration in ultramafic rocks leads to serpentinization and the formation of subaerial, low temperature, hydrothermal alkaline springs. Here, we present a detailed investigation of the mineral precipitation mechanisms and textural features of mineral precipitates, along as the geochemical and hydrological characterization, of two alkaline spring systems in the Semail ophiolite (Nasif and Khafifah sites, Wadi Tayin massif). The main aim of the study is to provide new insights into mineral and textural variations in active, on-land, alkaline vents of the Oman ophiolite. Discharge of circulating fluids forms small-scale, localized hydrological catchments consisting in unevenly interconnected ponds. Three different types of waters can be distinguished within the pond systems: i) Mg-type; alkaline (7.9 < pH < 9.5), Mg-HCO3-rich waters; ii) Ca-type; hyper-alkaline (pH > 11.6), Ca-OH-rich waters; and iii) Mix-type waters arising from the mixing of Mg-type and Ca-type waters (9.6 < pH < 11.5). Phreeqc geochemical speciation software was used to determine the saturation state and the relationship between the theoretical supersaturation (S) and rate of supersaturation (S˚ ) of solid phases. Simple mixing models using Phreeqc MIX_code revealed good mixing correlation (R2 ≥0.93) between measured and predicted values for K, Na, Cl, Mg and sulphate. Al, Ca, Si, Ba, Sr and TIC showed poorer correlations. Mineral and textural characterization from different types of water and individual ponds were carried out by X-ray diffraction (XRD), Raman spectroscopy and field-emission scanning electron microscopy coupled to dispersive energy spectroscopy (FE-SEM-EDS). Aragonite and calcite are the dominant minerals (95 vol.%) of the total mineralogical index in all sites. Mg-type waters host hydrated magnesium carbonates (nesquehonite) and magnesium hydroxycarbonate hydrates (artinite) due to evaporation. Brucite, hydromagnesite and dypingite presence in Mix-type waters

  12. Thermodynamics of the Sorption of Benzimidazoles on Octadecyl Silica Gel from Water-Methanol Eluents

    NASA Astrophysics Data System (ADS)

    Shafigulin, R. V.; Bulanova, A. V.

    2018-02-01

    The standard enthalpy and entropy component of transferring benzimidazoles from water-methanol solutions to surfaces of octadecyl silica gel are determined using reversed-phase high-performance liquid chromatography (RP HPLC). The dependences between the enthalpy and polarizability of the molecules of the studied benzimidazoles, the enthalpy and the entropy factor are studied, and the influence of the quantitative composition of the water-methanol solution on the enthalpy are studied.

  13. Efficient artificial mineralization route to decontaminate Arsenic(III) polluted water - the Tooeleite Way

    NASA Astrophysics Data System (ADS)

    Malakar, Arindam; Das, Bidisa; Islam, Samirul; Meneghini, Carlo; de Giudici, Giovanni; Merlini, Marco; Kolen'Ko, Yury V.; Iadecola, Antonella; Aquilanti, Giuliana; Acharya, Somobrata; Ray, Sugata

    2016-05-01

    Increasing exposure to arsenic (As) contaminated ground water is a great threat to humanity. Suitable technology for As immobilization and removal from water, especially for As(III) than As(V), is not available yet. However, it is known that As(III) is more toxic than As(V) and most groundwater aquifers, particularly the Gangetic basin in India, is alarmingly contaminated with it. In search of a viable solution here, we took a cue from the natural mineralization of Tooeleite, a mineral containing Fe(III) and As(III)ions, grown under acidic condition, in presence of SO42- ions. Complying to this natural process, we could grow and separate Tooeleite-like templates from Fe(III) and As(III) containing water at overall circumneutral pH and in absence of SO42- ions by using highly polar Zn-only ends of wurtzite ZnS nanorods as insoluble nano-acidic-surfaces. The central idea here is to exploit these insoluble nano-acidic-surfaces (called as INAS in the manuscript) as nucleation centres for Tooeleite growth while keeping the overall pH of the aqueous media neutral. Therefore, we propose a novel method of artificial mineralization of As(III) by mimicking a natural process at nanoscale.

  14. Hypersonic aerothermodynamic and scramjet research using high enthalpy shock tunnel

    NASA Astrophysics Data System (ADS)

    Itoh, K.; Ueda, S.; Tanno, H.; Komuro, T.; Sato, K.

    A high enthalpy shock tunnel is a potential facility for gaining knowledge to develop modern aerothermodynamic and propulsion technologies. The largest high enthalpy shock tunnel HIEST was built at NAL Kakuda in 1997, aiming for aerothermodynamic tests of Japan's space vehicle HOPE and scramjet propulsion systems. Selected topics from the experimental studies carried out using HIEST so far, such as the nonequilibrium aerodynamics of HOPE, the surface catalytic effect on aerodynamic heating and scramjet performance are described.

  15. Kinetics of mineralization of organic compounds at low concentrations in soil.

    PubMed Central

    Scow, K M; Simkins, S; Alexander, M

    1986-01-01

    The kinetics of mineralization of 14C-labeled phenol and aniline were measured at initial concentrations ranging from 0.32 to 5,000 ng and 0.30 ng to 500 micrograms/g of soil, respectively. Mineralization of phenol at concentrations less than or equal to 32 ng/g of soil and of aniline at all concentrations began immediately, and the curves for the evolution of labeled CO2 were biphasic. The patterns of mineralization of 4.0 ng of 2,4-dichlorophenol per g of soil and 20 ng of nitrilotriacetic acid per g of soil were similar to the patterns for phenol and aniline. The patterns of mineralization of 1.0 to 100 ng of p-nitrophenol and 6.0 ng of benzylamine per g of soil were also biphasic but after a short apparent lag period. The curves of CO2 evolution from higher concentrations of phenol and p-nitrophenol had increasing apparent lag phases and were S-shaped or linear. Cumulative plots of the percentage of substrate converted to CO2 were fit by nonlinear regression to first-order, integrated Monod, logistic, logarithmic, zero-order, three-half-order, and two-compartment models. None of the models of the Monod family provided the curve of best fit to any of the patterns of mineralization. The linear growth form of the three-half-order model provided the best fit for the mineralization of p-nitrophenol, with the exception of the lowest concentrations, and of benzylamine. The two-compartment model provided the best fit for the mineralization of concentrations of phenol below 100 ng/g, of several concentrations of aniline, and of nitrilotriacetic acid. It is concluded that models derived from the Monod equation, including the first-order model, do not adequately describe the kinetics of mineralization of low concentrations of chemicals added to soil. PMID:3729388

  16. Insights on activation enthalpy for non-Schmid slip in body-centered cubic metals

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hale, Lucas M.; Lim, Hojun; Zimmerman, Jonathan A.

    2014-12-18

    We use insights gained from atomistic simulation to develop an activation enthalpy model for dislocation slip in body-centered cubic iron. Furthermore, using a classical potential that predicts dislocation core stabilities consistent with ab initio predictions, we quantify the non-Schmid stress-dependent effects of slip. The kink-pair activation enthalpy is evaluated and a model is identified as a function of the general stress state. Thus, our model enlarges the applicability of the classic Kocks activation enthalpy model to materials with non-Schmid behavior.

  17. Understanding hydrothermal circulation patterns at a low-enthalpy thermal spring using audio-magnetotelluric data: A case study from Ireland

    NASA Astrophysics Data System (ADS)

    Blake, Sarah; Henry, Tiernan; Muller, Mark R.; Jones, Alan G.; Moore, John Paul; Murray, John; Campanyà, Joan; Vozar, Jan; Walsh, John; Rath, Volker

    2016-09-01

    re-circulation of meteoric waters within this structurally controlled hydrothermal circulation system. This paper illustrates how AMT may be useful in a multi-disciplinary investigation of an intermediate-depth (100-1000 m), low-enthalpy, geothermal target, and shows how the different strands of inquiry from a multi-disciplinary investigation may be woven together to gain a deeper understanding of a complex hydrothermal system.

  18. Study on the leaching of phthalates from polyethylene terephthalate bottles into mineral water.

    PubMed

    Keresztes, Szilvia; Tatár, Enikő; Czégény, Zsuzsanna; Záray, Gyula; Mihucz, Victor G

    2013-08-01

    Carbonated and non-carbonated mineral water samples bottled in 0.5-L, 1.5-L and 2.0-L polyethylene terephthalate (PET) containers belonging to three different water brands commercialized in Hungary were studied in order to determine their phthalate content by gas chromatography-mass spectrometry. Among the six investigated phthalates, diisobutyl phthalate, di-n-butyl-phthalate, benzyl-butyl phthalate and di(2-ethyl-hexyl) phthalate (DEHP) were determined in non-carbonated samples as follows: <3.0 ng L(-1)-0.2 μg L(-1), <6.6 ng L(-1)-0.8 μg L(-1), <6.0 ng L(-1)-0.1 μg L(-1) and <16.0 ng L(-1)-1.7 μg L(-1), respectively. Any of the above-mentioned phthalate esters could be detected in carbonated mineral water samples. DEHP was the most abundant phthalate in the investigated samples. It could be detected after 44 days of storage at 22 °C and its leaching was the most pronounced when samples were stored over 1200 days. Mineral water purchased in PET bottles of 0.5L had the highest phthalate concentrations compared to those obtained for waters of the identical brand bottled in 1.5-L or 2.0-L PET containers due to the higher surface/volume ratio. No clear trend could be established for phthalate leaching when water samples were kept at higher temperatures (max. 60 °C) showing improper storage conditions. Phthalate determination by pyrolysis-gas chromatography/mass spectrometric measurements in the plastic material as well as in the aqueous phase proved the importance of the quality of PET raw material used for the production of the pre-form (virgin vs. polymer containing recycled PET). Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Water Storage and Related Physical Characteristics of Four Mineral Soils in North Central Minnesota

    Treesearch

    E. S. Verry

    1969-01-01

    Soil water storage in a 7.5 foot profile varied nearly 100 percent (7.9 to 15.5 inches) among four mineral soils ranging from a sand to sandy loam. Bulk density, size fractions, and four water retention values are tabulated for each horizon.

  20. Interaction of inorganic anions with iron-mineral adsorbents in aqueous media--a review.

    PubMed

    Kumar, Eva; Bhatnagar, Amit; Hogland, William; Marques, Marcia; Sillanpää, Mika

    2014-01-01

    A number of inorganic anions (e.g., nitrate, fluoride, bromate, phosphate, and perchlorate) have been reported in alarming concentrations in numerous drinking water sources around the world. Their presence even in very low concentrations may cause serious environmental and health related problems. Due to the presence and significance of iron minerals in the natural aquatic environment and increasing application of iron in water treatment, the knowledge of the structure of iron and iron minerals and their interactions with aquatic pollutants, especially inorganic anions in water are of great importance. Iron minerals have been known since long as potential adsorbents for the removal of inorganic anions from aqueous phase. The chemistry of iron and iron minerals reactions in water is complex. The adsorption ability of iron and iron minerals towards inorganic anions is influenced by several factors such as, surface characteristics of the adsorbent (surface area, density, pore volume, porosity, pore size distribution, pHpzc, purity), pH of the solution, and ionic strength. Furthermore, the physico-chemical properties of inorganic anions (pore size, ionic radius, bulk diffusion coefficient) also significantly influence the adsorption process. The aim of this paper is to provide an overview of the properties of iron and iron minerals and their reactivity with some important inorganic anionic contaminants present in water. It also summarizes the usage of iron and iron minerals in water treatment technology. © 2013.

  1. The composition of coexisting jarosite-group minerals and water from the Richmond mine, Iron Mountain, California

    USGS Publications Warehouse

    Jamieson, Heather E.; Robinson, Clare; Alpers, Charles N.; Nordstrom, D. Kirk; Poustovetov, Alexei; Lowers, Heather A.

    2005-01-01

    Jarosite-group minerals accumulate in the form of stalactites and fine-grained mud on massive pyrite in the D drift of the Richmond mine, Iron Mountain, California. Water samples were collected by placing beakers under the dripping stalactites and by extracting pore water from the mud using a centrifuge. The water is rich in Fe3+ and SO4 2−, with a pH of approximately 2.1, which is significantly higher than the extremely acidic waters found elsewhere in the mine. Electron-microprobe analysis and X-ray mapping indicate that the small crystals (<10 μm in diameter) are compositionally zoned with respect to Na and K, and include hydronium jarosite corresponding to the formula (H3O)0.6K0.3Na0.1Fe3 3+(SO4)2(OH)6. The proton-microprobe analyses indicate that the jarosite-group minerals contain significant amounts of As, Pb and Zn, and minor levels of Bi, Rb, Sb, Se, Sn and Sr. Speciation modeling indicates that the drip waters are supersaturated with respect to jarosite-group minerals. The expected range in composition of jarosite-group solid-solution in equilibrium with the pore water extracted from the mud was found to be consistent with the observed range in composition.

  2. Bone Mineral 31P and Matrix-Bound Water Densities Measured by Solid-State 1H and 31P MRI

    PubMed Central

    Seifert, Alan C.; Li, Cheng; Rajapakse, Chamith S.; Bashoor- Zadeh, Mahdieh; Bhagat, Yusuf A.; Wright, Alexander C.; Zemel, Babette S.; Zavaliangos, Antonios; Wehrli, Felix W.

    2014-01-01

    Bone is a composite material consisting of mineral and hydrated collagen fractions. MRI of bone is challenging due to extremely short transverse relaxation times, but solid-state imaging sequences exist that can acquire the short-lived signal from bone tissue. Previous work to quantify bone density via MRI used powerful experimental scanners. This work seeks to establish the feasibility of MRI-based measurement on clinical scanners of bone mineral and collagen-bound water densities, the latter as a surrogate of matrix density, and to examine the associations of these parameters with porosity and donors’ age. Mineral and matrix-bound water images of reference phantoms and cortical bone from 16 human donors, ages 27-97 years, were acquired by zero-echo-time 31P and 1H MRI on whole body 7T and 3T scanners, respectively. Images were corrected for relaxation and RF inhomogeneity to obtain density maps. Cortical porosity was measured by micro-CT, and apparent mineral density by pQCT. MRI-derived densities were compared to x-ray-based measurements by least-squares regression. Mean bone mineral 31P density was 6.74±1.22 mol/L (corresponding to 1129±204 mg/cc mineral), and mean bound water 1H density was 31.3±4.2 mol/L (corresponding to 28.3±3.7 %v/v). Both 31P and bound water (BW) densities were correlated negatively with porosity (31P: R2 = 0.32, p < 0.005; BW: R2 = 0.63, p < 0.0005) and age (31P: R2 = 0.39, p < 0.05; BW: R2 = 0.70, p < 0.0001), and positively with pQCT density (31P: R2 = 0.46, p < 0.05; BW: R2 = 0.50, p < 0.005). In contrast, the bone mineralization ratio (expressed here as the ratio of 31P density to bound water density), which is proportional to true bone mineralization, was found to be uncorrelated with porosity, age, or pQCT density. This work establishes the feasibility of image-based quantification of bone mineral and bound water densities using clinical hardware. PMID:24846186

  3. Tunable Manipulation of Mineral Carbonation Kinetics in Nanoscale Water Films via Citrate Additives.

    PubMed

    Miller, Quin R S; Schaef, Herbert T; Kaszuba, John P; Qiu, Lin; Bowden, Mark E; McGrail, Bernard P

    2018-06-06

    We explored the influence of a model organic ligand on mineral carbonation in nanoscale interfacial water films by conducting five time-resolved in situ X-ray diffraction (XRD) experiments at 50 °C. Forsterite was exposed to water-saturated supercritical carbon dioxide (90 bar) that had been equilibrated with 0-0.5 m citrate (C 6 H 5 O 7 -3 ) solutions. The experimental results demonstrated that greater concentrations of citrate in the nanoscale interfacial water film promoted the precipitation of magnesite (MgCO 3 ) relative to nesquehonite (MgCO 3 ·3H 2 O). At the highest concentrations tested, magnesite nucleation and growth were inhibited, lowering the carbonation rate constant from 9.1 × 10 -6 to 3.6 × 10 -6 s -1 . These impacts of citrate were due to partial dehydration of Mg 2+ (aq) and the adsorption of citrate onto nuclei and magnesite surfaces. This type of information may be used to predict and tailor subsurface mineralization rates and pathways.

  4. Underground mineral extraction

    NASA Technical Reports Server (NTRS)

    Miller, C. G.; Stephens, J. B.

    1980-01-01

    A method was developed for extracting underground minerals such as coal, which avoids the need for sending personnel underground and which enables the mining of steeply pitched seams of the mineral. The method includes the use of a narrow vehicle which moves underground along the mineral seam and which is connected by pipes or hoses to water pumps at the surface of the Earth. The vehicle hydraulically drills pilot holes during its entrances into the seam, and then directs sideward jets at the seam during its withdrawal from each pilot hole to comminute the mineral surrounding the pilot hole and combine it with water into a slurry, so that the slurried mineral can flow to a location where a pump raises the slurry to the surface.

  5. Influence of mineral colloids and humic substances on uranium(VI) transport in water-saturated geologic porous media

    NASA Astrophysics Data System (ADS)

    Wang, Qing; Cheng, Tao; Wu, Yang

    2014-12-01

    Mineral colloids and humic substances often co-exist in subsurface environment and substantially influence uranium (U) transport. However, the combined effects of mineral colloids and humic substances on U transport are not clear. This study is aimed at quantifying U transport and elucidating geochemical processes that control U transport when both mineral colloids and humic acid (HA) are present. U-spiked solutions/suspensions were injected into water-saturated sand columns, and U and colloid concentrations in column effluent were monitored. We found that HA promoted U transport via (i) formation of aqueous U-HA complexes, and (ii) competition against aqueous U for surface sites on transport media. Illite colloids had no influence on U transport at pH 5 in the absence of HA due to low mobility of the colloids. At pH 9, U desorbed from mobile illite and the presence of illite decreased U transport. At pH 5, high U transport occurred when both illite colloids and HA were present, which was attributed to enhanced U adsorption to illite colloids via formation of ternary illite-HA-U surface complexes, and enhanced illite transport due to HA attachment to illite and transport media. This study demonstrates that the combined effects of mineral colloids and HA on contaminant transport is different from simple addition of the individual effect.

  6. Radioprotective Effects of Sulfur-containing Mineral Water of Ramsar Hot Spring with High Natural Background Radiation on Mouse Bone Marrow Cells.

    PubMed

    Heidari, A H; Shabestani Monfared, A; Mozdarani, H; Mahmoudzadeh, A; Razzaghdoust, A

    2017-12-01

    We intend to study the inhibitory effect of sulfur compound in Ramsar hot spring mineral on tumor-genesis ability of high natural background radiation. The radioprotective effect of sulfur compounds was previously shown on radiation-induced chromosomal aberration, micronuclei in mouse bone marrow cells and human peripheral lymphocyte. Ramsar is known for having the highest level of natural background radiation on Earth. This study was performed to show the radioprotective effect of sulfur-containing Ramsar mineral water on mouse bone marrow cells. Mice were fed three types of water (drinking water, Ramsar radioactive water containing sulfur and Ramsar radioactive water whose sulfur was removed). Ten days after feeding, mice were irradiated by gamma rays (0, 2 and 4 Gy). 48 and 72 hours after irradiating, mice were killed and femurs were removed. Frequency of micronuclei was determined in bone marrow erythrocytes. A significant reduction was shown in the rate of micronuclei polychromatic erythrocyte in sulfur-containing hot spring water compared to sulfur-free water in hot spring mineral water. Gamma irradiation induced significant increases in micronuclei polychromatic erythrocyte (MNPCE) and decreases in polychromatic erythrocyte/polychromatic erythrocyte + normochromatic erythrocyte ratio (PCEs/PCEs+NCEs) (P < 0.001) in sulfur-containing hot spring water compared to sulfur-free hot spring mineral water. Also, apparently there was a significant difference between drinking water and sulfur-containing hot spring water in micronuclei polychromatic erythrocyte and polychromatic erythrocyte/polychromatic erythrocyte+ normochromatic erythrocyte ratio. The results indicate that sulfur-containing mineral water could result in a significant reduction in radiation-induced micronuclei representing the radioprotective effect of sulfur compounds.

  7. Radioactivity and geochemistry of selected mineral-spring waters in the Western United States; basic data and multivariate statistical analysis

    USGS Publications Warehouse

    Felmlee, J.K.; Cadigan, R.A.

    1982-01-01

    Multivariate statistical analyses were performed on data from 156 mineral-spring sites in nine Western States to analyze relationships among the various parameters measured in the spring waters. Correlation analysis and R-mode factor analysis indicate that three major factors affect water composition in the spring systems studied: (1) duration of water circulation, (2) depth of water circulation, and (3) partial pressure of carbon dioxide. An examination of factor scores indicates that several types of hydrogeologic systems were sampled. Most of the samples are (1) older water from deeper circulating systems having relatively high salinity, high temperature, and low Eh or (2) younger water from shallower circulating systems having relatively low salinity, low temperature, and high Eh. The rest of the samples are from more complex systems. Any of the systems can have a relatively high or low content of dissolved carbonate species, resulting in a low or high pH, respectively. Uranium concentrations are commonly higher in waters of relatively low temperature and high Eh, and radium concentrations are commonly higher in waters having a relatively high carbonate content (low pH) and, secondarily, relatively high salinity. Water samples were collected and (or) measurements were taken at 156 of the 171 mineral-spring sites visited. Various samples were analyzed for radium, uranium, radon, helium, and radium-228 as well as major ions and numerous trace elements. On-site measurements for physical properties including temperature, specific conductance, pH, Eh, and dissolved oxygen were made. All constituents and properties show a wide range of values. Radium concentrations range from less than 0.01 to 300 picocuries per liter; they average 1.48 picocuries per liter and have an anomaly threshold value of 171 picocuries per liter for the samples studied. Uranium concentrations range from less than 0.01 to 120 micrograms per liter and average 0.26 micrograms per liter; they

  8. Enthalpy relaxation studies of two structurally related amorphous drugs and their binary dispersions.

    PubMed

    Bansal, Shyam Sunder; Kaushal, Aditya Mohan; Bansal, Arvind Kumar

    2010-11-01

    The purpose of the current study was to evaluate the enthalpy relaxation behavior of valdecoxib (VLB) and etoricoxib (ETB) and their binary dispersions to derive relaxation constants and to understand their molecular mobilities. Solid dispersions of VLB and ETB were prepared with 1%, 2%, 5%, 10%, 15%, and 20% (w/w) concentrations of polyvinylpyrrolidone (PVP) in situ using differential scanning calorimetry (DSC). Enthalpy relaxation studies were carried out with isothermal storage periods of 1, 2, 4, 6, 16, and 24 hours at 40°C and 0% relative humidity (RH). PVP increased the glass transition temperature (T(g)) and decreased the enthalpy relaxation. Significant differences between two drugs were observed with respect to their relaxation behavior which may be due to differences in intermolecular interactions as predicted by Couchman-Karasz equation and molecular mobility. Kohlrausch-Williams-Watts equation was found to be inadequate in describing complex molecular relaxations in binary dispersions. The enthalpy relaxation behavior of VLB and ETB was found to be significantly different. PVP stabilized VLB significantly; however, its effect on ETB was negligible. The extent of enthalpy relaxation was found to correlate with hydrogen bonding tendency of the drug molecules. The outcome can help in rational designing of amorphous systems with optimal performance.

  9. Dissociation constants, neutralization enthalpies and reactions of 3-styryl-2-mercaptopropenoic and 3-(1-naphthyl)-2-mercaptopropenoic acids.

    PubMed

    Izquierdo, A; Bosch, E; Beltran, J L

    1984-06-01

    Dissociation constants (pK(a1) and pK(a2) in water-ethanol medium for 3-styryl-2-mercaptopropenoic and 3-(1-naphthyl)-2-mercaptopropenoic acid have been determined potentiometrically, and pK(a2) for both in aqueous medium, spectrophotometrically. Neutralization enthalpies in water-ethanol medium have been determined by thermometric titration. The reactions with metal ions have been studied, and the main reactions are described. The most sensitive reactions are with titanium(IV) (pD = 7.00) and nickel(II) (pD = 6.50).

  10. Energy Landscape of Water and Ethanol on Silica Surfaces

    DOE PAGES

    Wu, Di; Guo, Xiaofeng; Sun, Hui; ...

    2015-06-26

    Fundamental understanding of small molecule–silica surface interactions at their interfaces is essential for the scientific, technological, and medical communities. We report direct enthalpy of adsorption (Δh ads) measurements for ethanol and water vapor on porous silica glass (CPG-10), in both hydroxylated and dehydroxylated (hydrophobic) forms. Results suggest a spectrum of energetics as a function of coverage, stepwise for ethanol but continuous for water. The zero-coverage enthalpy of adsorption for hydroxylated silica shows the most exothermic enthalpies for both water (-72.7 ± 3.1 kJ/mol water) and ethanol (-78.0 ± 1.9 kJ/mol ethanol). The water adsorption enthalpy becomes less exothermic gradually untilmore » reaching its only plateau (-20.7 ± 2.2 kJ/mol water) reflecting water clustering on a largely hydrophobic surface, while the enthalpy of ethanol adsorption profile presents two well separated plateaus, corresponding to strong chemisorption of ethanol on adsorbate-free silica surface (-66.4 ± 4.8 kJ/mol ethanol), and weak physisorption of ethanol on ethanol covered silica (-4.0 ± 1.6 kJ/mol ethanol). On the other hand, dehydroxylation leads to missing water–silica interactions, whereas the number of ethanol binding sites is not impacted. The isotherms and partial molar properties of adsorption suggest that water may only bind strongly onto the silanols (which are a minor species on silica glass), whereas ethanol can interact strongly with both silanols and the hydrophobic areas of the silica surface.« less

  11. Measurement of natural radionuclides in Malaysian bottled mineral water and consequent health risk estimation

    NASA Astrophysics Data System (ADS)

    Priharti, W.; Samat, S. B.; Yasir, M. S.

    2015-09-01

    The radionuclides of 226Ra, 232Th and 40K were measured in ten mineral water samples, of which from the radioactivity obtained, the ingestion doses for infants, children and adults were calculated and the cancer risk for the adult was estimated. Results showed that the calculated ingestion doses for the three age categories are much lower than the average worldwide ingestion exposure of 0.29 mSv/y and the estimated cancer risk is much lower than the cancer risk of 8.40 × 10-3 (estimated from the total natural radiation dose of 2.40 mSv/y). The present study concludes that the bottled mineral water produced in Malaysia is safe for daily human consumption.

  12. Preliminary Results from Electric Arc Furnace Off-Gas Enthalpy Modeling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nimbalkar, Sachin U; Thekdi, Arvind; Keiser, James R

    2015-01-01

    This article describes electric arc furnace (EAF) off-gas enthalpy models developed at Oak Ridge National Laboratory (ORNL) to calculate overall heat availability (sensible and chemical enthalpy) and recoverable heat values (steam or power generation potential) for existing EAF operations and to test ORNL s new EAF waste heat recovery (WHR) concepts. ORNL s new EAF WHR concepts are: Regenerative Drop-out Box System and Fluidized Bed System. The two EAF off-gas enthalpy models described in this paper are: 1.Overall Waste Heat Recovery Model that calculates total heat availability in off-gases of existing EAF operations 2.Regenerative Drop-out Box System Model in whichmore » hot EAF off-gases alternately pass through one of two refractory heat sinks that store heat and then transfer it to another gaseous medium These models calculate the sensible and chemical enthalpy of EAF off-gases based on the off-gas chemical composition, temperature, and mass flow rate during tap to tap time, and variations in those parameters in terms of actual values over time. The models provide heat transfer analysis for the aforementioned concepts to confirm the overall system and major component sizing (preliminary) to assess the practicality of the systems. Real-time EAF off-gas composition (e.g., CO, CO2, H2, and H2O), volume flow, and temperature data from one EAF operation was used to test the validity and accuracy of the modeling work. The EAF off-gas data was used to calculate the sensible and chemical enthalpy of the EAF off-gases to generate steam and power. The article provides detailed results from the modeling work that are important to the success of ORNL s EAF WHR project. The EAF WHR project aims to develop and test new concepts and materials that allow cost-effective recovery of sensible and chemical heat from high-temperature gases discharged from EAFs.« less

  13. Molecular dynamics simulation of water at mineral surfaces: Structure, dynamics, energetics and hydrogen bonding

    NASA Astrophysics Data System (ADS)

    Kalinichev, A. G.; Wang, J.; Kirkpatrick, R.

    2006-05-01

    Fundamental molecular-level understanding of the properties of aqueous mineral interfaces is of great importance for many geochemical and environmental systems. Interaction between water and mineral surfaces substantially affects the properties of both phases, including the reactivity and functionality of the substrate surface, and the structure, dynamics, and energetics of the near surface aqueous phase. Experimental studies of interfacial water structure and dynamics using surface-sensitive techniques such as sum-frequency vibrational spectroscopy or X-ray and neutron reflectivity are not always possible for many practically important substrates, and their results often require interpretation concerning the atomistic mechanisms responsible for the observed behavior. Molecular computer simulations can provide new insight into the underlying molecular- level relationships between the inorganic substrate structure and composition and the structure, ordering, and dynamics of interfacial water. We have performed a series of molecular dynamics (MD) computer simulations of aqueous interfaces with several silicates (quartz, muscovite, and talc) and hydroxides (brucite, portlandite, gibbsite, Ca/Al and Mg/Al double hydroxides) to quantify the effects of the substrate mineral structure and composition on the structural, transport, and thermodynamic properties of water on these mineral surfaces. Due to the prevalent effects of the development of well-interconnected H-bonding networks across the mineral- water interfaces, all the hydroxide surfaces (including a fully hydroxylated quartz surface) show very similar H2O density profiles perpendicular to the interface. However, the predominant orientations of the interfacial H2O molecules and their detailed 2-dimensional near-surface structure and dynamics parallel to the interface are quite different reflecting the differences in the substrate structural charge distribution and the density and orientations of the surface OH

  14. High Enthalpy Effects on Two Boundary Layer Disturbances in Supersonic and Hypersonic Flow

    NASA Astrophysics Data System (ADS)

    Wagnild, Ross Martin

    The fluid flow phenomenon of boundary layer transition is a complicated and difficult process to model and predict. The importance of the state of the boundary layer with regard to vehicle design cannot be understated. The high enthalpy environment in which high speed vehicles operate in further complicates the transition process by adding several more degrees of freedom. In this environment, the internal properties of the gas can stabilize or destabilize the boundary layer as well as modify the disturbances that cause transition. In the current work, the interaction of two types of disturbances with the high enthalpy flow environment are analyzed. The first is known as a second mode disturbance, which is acoustic in nature. The second type is known as a transient growth disturbance and is associated with flows behind roughness elements. Theoretical analyses, linear stability analyses, and computation fluid dynamics (CFD) are used to determine the ways in which these disturbances interact with the high enthalpy environment as well as the consequences of these interactions. First, acoustic wave are directly studied in order to gain a basic understanding of the response of second mode disturbances in the high enthalpy boundary layer. Next, this understanding is used in interpreting the results of several computations attempting to simulate the flow through a high enthalpy flow facility as well as experiments attempting to take advantage of the acoustic interaction with the high enthalpy environment. Because of the difficulty in modeling these experiments, direct simulations of acoustic waves in a hypersonic flow of a gas with molecular vibration are performed. Lastly, compressible transient growth disturbances are simulated using a linear optimal disturbance solver as well as a CFD solver. The effect of an internal molecular process on this type of disturbance is tested through the use of a vibrational mode. It is the goal of the current work to reinforce the

  15. Integrated Spectroscopic Studies of Anhydrous Sulfate Minerals

    NASA Technical Reports Server (NTRS)

    Lane, M. D.; Bishop, J. L.; Dyar, M. D.; Cloutis, E.; Forray, F. L.; Hiroi, T.

    2005-01-01

    Sulfates have been identified in Martian soils and bedrock and are emerging as an important indicator for aqueous activity on Mars. Sulfate minerals can form in a variety of low-temperature (evaporitic; chemical-weathering) and high-temperature (volcanic/fumarolic; hydrothermal) environments and their formational environments can range from alkaline to acidic. Although sulfates generally form in the presence of water, not all sulfates are hydrous or contain water in their structures. Many of these anhydrous sulfates (Dana group 28; Strunz class 67A) are minerals that form as accompanying phases to the main minerals in ore deposits or as replacement deposits in sedimentary rocks. However, some form from thermal decomposition of OH or H2O-bearing sulfates, such as from the reaction [1]: jarosite = yavapaiite + Fe2O3 + H2O. Where known, the stability fields of these minerals all suggest that they would be stable under martian surface conditions [2]. Thus, anhydrous sulfate minerals may contribute to martian surface mineralogy, so they must be well-represented in spectral libraries used for interpretation of the Martian surface. We present here the preliminary results of an integrated study of emittance, reflectance, and Mossbauer spectroscopy of a suite of wel-lcharacterized anhydrous sulfates.

  16. [Investigation of concentration levels of chromium(VI) in bottled mineral and spring waters by high performance ion chromatography technique with application of postcolumn reaction with 1,5-diphenylcarbazide and VIS detection].

    PubMed

    Swiecicka, Dorota; Garboś, Sławomir

    2008-01-01

    The aim of this work was optimization and validation of the method of determination of Cr(VI) existing in the form of chromate(VI) in mineral and spring waters by High Performance Ion Chromatography (HPIC) technique with application of postcolumn reaction with 1,5-diphenylcarbazide and VIS detection. Optimization of the method performed with the use of initial apparatus parameters and chromatographic conditions from the Method 218.6 allowed to lowering detection limit for Cr(VI) from 400 ng/l to 2 ng/l. Thanks to very low detection limit achieved it was possible to determine of Cr(VI) concentrations in 25 mineral and spring waters presented at Polish market. In the cases of four mineral and spring waters analyzed, determined Cr(VI) concentrations were below of quantification limit (< 4 ng/l) but simultaneously in another mineral and spring waters the concentrations of chromium(VI) were determined in the range of 5.6 - 1281 ng/l. The fact of existence of different Cr(VI) concentrations in investigated waters could be connected with secondary contamination of mineral and spring waters by chromium coming from metal installations and fittings. One should be underlined that even the highest determined concentration level of chromium(VI) was below of the maximum admissible concentration of total chromium presented in Polish Decree of Minister of Health from April 29th 2004. Therefore after taking into account determined in this work concentration of Cr(VI), the consumption of all waters analyzed in this study does not lead to essential human health risk.

  17. [Physicochemical quality of drinking water in Southern Algeria: study of excess mineral salts].

    PubMed

    Djellouli, H M; Taleb, S; Harrache-Chettouh, D; Djaroud, S

    2005-01-01

    The aim of this study was to determine the physicochemical composition of water intended for human consumption in several regions of Southern Algeria. Excess minerals in drinking water, including magnesium, calcium, sulfates and fluorides play a fundamental role in the prevention of urinary calculi, which are formed mainly from calcium oxalate. The ever-increasingly prevalence of this disorder and its recurrence make it a real public health problem in Algeria. The most elementary preventive treatment, recommended to all subjects with lithiasis, is to drink 2 to 3 L water distributed throughout the (24-hour) day. This study began by conducting a physicochemical analysis of the principal components of water from several sources. We will subsequently test it to examine the effects of its mineral salts on the crystallization kinetics of the principal component of calculi (calcium oxalate). The results indicate that 77.5 % of the samples had magnesium concentrations ([Mg 2+] > 50 mg/L), 95 % were sulfated, with sulfate ion concentrations exceeding the standard recommended by WHO ([SO4 2-] > 250 mg/L). Moreover, 57.5 % had excess fluoride levels, [F-] > 1.5 mg/L, and 65 % excessive calcium concentrations, with Ca 2+ > 150 mg/L.

  18. Accumulation and transport of minerals by marine protozoa. Progress report, September 1, 1976--November 30, 1977. [Mineral concentration by Tintinnida in coastal waters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gold, K.

    Tintinnida are abundant microzooplankton found in all of the world's oceans, and important components of the marine food web as predators, prey, and as regenerators of nutrients. The agglutinated forms take on added importance in coastal waters. Representatives of this group have the unique ability among ciliates to pick up particles from the environment and incorporate them into the lorica. The ecological significance of the phenomenon lies in: it is a pathway whereby radionuclides, metals and other toxic substance can be biologically concentrated and transferred from sediments and the water column to the biota; from the viewpoint of microzooplankton asmore » indicators of environmental perturbations, pollution, or water mass movements, it is important to determine whether minerals accumulated on the lorica can serve as a guide to the site where they originate. Results are reported from studies in progress on the types of mineral matter accumulated by tintinnids.« less

  19. Skin-friction measurements in high-enthalpy hypersonic boundary layers

    NASA Astrophysics Data System (ADS)

    Goyne, C. P.; Stalker, R. J.; Paull, A.

    2003-06-01

    Skin-friction measurements are reported for high-enthalpy and high-Mach-number laminar, transitional and turbulent boundary layers. The measurements were performed in a free-piston shock tunnel with air-flow Mach number, stagnation enthalpy and Reynolds numbers in the ranges of 4.4 6.7, 3 13 MJ kg(-1) and 0.16× 10(6) 21× 10(6) , respectively. Wall temperatures were near 300 K and this resulted in ratios of wall enthalpy to flow-stagnation enthalpy in the range of 0.1 0.02. The experiments were performed using rectangular ducts. The measurements were accomplished using a new skin-friction gauge that was developed for impulse facility testing. The gauge was an acceleration compensated piezoelectric transducer and had a lowest natural frequency near 40 kHz. Turbulent skin-friction levels were measured to within a typical uncertainty of ± 7%. The systematic uncertainty in measured skin-friction coefficient was high for the tested laminar conditions; however, to within experimental uncertainty, the skin-friction and heat-transfer measurements were in agreement with the laminar theory of van Driest (1952). For predicting turbulent skin-friction coefficient, it was established that, for the range of Mach numbers and Reynolds numbers of the experiments, with cold walls and boundary layers approaching the turbulent equilibrium state, the Spalding & Chi (1964) method was the most suitable of the theories tested. It was also established that if the heat transfer rate to the wall is to be predicted, then the Spalding & Chi (1964) method should be used in conjunction with a Reynolds analogy factor near unity. If more accurate results are required, then an experimentally observed relationship between the Reynolds analogy factor and the skin-friction coefficient may be applied.

  20. Determination of ideal-gas enthalpies of formation for key compounds:

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Steele, W.V.; Chirico, R.D.; Nguyen, A.

    1991-10-01

    The results of a study aimed at improvement of group-contribution methodology for estimation of thermodynamic properties of organic and organosilicon substances are reported. Specific weaknesses where particular group-contribution terms were unknown, or estimated because of lack of experimental data, are addressed by experimental studies of enthalpies of combustion in the condensed phase, vapor-pressure measurements, and differential scanning calorimetric (d.s.c.) heat-capacity measurements. Ideal-gas enthalpies of formation of ({plus minus})-butan-2-ol, tetradecan-1-ol, hexan-1,6-diol, methacrylamide, benzoyl formic acid, naphthalene-2,6-dicarboxylic acid dimethyl ester, and tetraethylsilane are reported. A crystalline-phase enthalpy of formation at 298.15 K was determined for naphthalene-2,6-dicarboxylic acid, which decomposed at 695 Kmore » before melting. The combustion calorimetry of tetraethylsilane used the proven fluorine-additivity methodology. Critical temperature and critical density were determined for tetraethylsilane with differential scanning calorimeter and the critical pressure was derived. Group-additivity parameters useful in the application of group- contribution correlations are derived. 112 refs., 13 figs., 19 tabs.« less

  1. Predicting consumer preferences for mineral composition of bottled and tap water.

    PubMed

    Platikanov, Stefan; Hernández, Alejandra; González, Susana; Luis Cortina, Jose; Tauler, Roma; Devesa, Ricard

    2017-01-01

    The overall liking for taste of water was correlated with the mineral composition of selected bottled and tap waters. Sixty-nine untrained volunteers assessed and rated twenty-five different commercial bottled and tap waters from. Water samples were physicochemical characterised by analysing conductivity, pH, total dissolved solids (TDS) and major anions and cations: HCO 3 - , SO 4 2- , Cl - , NO 3 - , Ca 2+ , Mg 2+ , Na + , and K + . Residual chlorine levels were also analysed in the tap water samples. Globally, volunteers preferred waters rich in calcium bicarbonate and sulfate, rather than in sodium chloride. This study also demonstrated that it was possible to accurately predict the overall liking by a Partial Least Squares regression using either all measured physicochemical parameters or a reduced number of them. These results were in agreement with previously published results using trained panellists. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. STIMULATION OF FUNDULUS BY HYDROCHLORIC AND FATTY ACIDS IN FRESH WATER, AND BY FATTY ACIDS, MINERAL ACIDS, AND THE SODIUM SALTS OF MINERAL ACIDS IN SEA WATER

    PubMed Central

    Allison, J. B.; Cole, William H.

    1934-01-01

    1. Fundulus heteroclitus was found to be a reliable experimental animal for studies on chemical stimulation in either fresh or sea water. 2. The response of Fundulus to hydrochloric, acetic, propionic, butyric, valeric, and caproic acids was determined in fresh water, while the same acids plus sulfuric and nitric, as well as the sodium salts of the mineral acids, were tested in sea water. 3. Stimulation of Fundulus by hydrochloric acid in fresh water is correlated with the effective hydrogen ion concentration. Stimulation by the n-aliphatic acids in the same environment is correlated with two factors, the effective hydrogen ion concentration and the potential of the non-polar group in the molecule. However, as the number of CH2 groups increases the stimulating effect increases by smaller and smaller amounts, approaching a maximum value. 4. Stimulation of Fundulus by hydrochloric, sulfuric, and nitric acids in sea water is correlated with the forces of primary valence which in turn are correlated with the change in hydrogen ion concentration of the sea water. The n-aliphatic acids increase in stimulating efficiency in sea water as the length of the carbon chain increases, but a limiting value is not reached as soon as in fresh water. 5. Only a slight difference in stimulation by hydrochloric acid is found in sea water and in fresh water. However, there is a significant difference in stimulation by the fatty acids in fresh and in sea water, which is partly explained by the different buffering capacities of the two media. It is to be noted that in the same environment two different fish, Fundulus and Eupomotis, give different results, while the same fish (Fundulus) in two different environments responds similarly to mineral acids but differently to fatty acids. These results illustrate that stimulation is a function of the interaction between environment and receptors, and that each is important in determining the response. 6. Stimulation by sodium chloride, nitrate

  3. Detection of ultra-low levels of DNA changes by drinking water: epidemiologically important finding.

    PubMed

    Kumari, Parmila; Kamiseki, Meiko; Biyani, Manish; Suzuki, Miho; Nemoto, Naoto; Aita, Takuyo; Nishigaki, Koichi

    2015-02-01

    The safety of drinking water is essential to our health. In this context, the mutagenicity of water needs to be checked strictly. However, from the methodological limit, the lower concentration (less than parts per million) of mutagenicity could not be detected, though there have been of interest in the effect of less concentration mutagens. Here, we describe a highly sensitive mutation assay that detects mutagens at the ppb level, termed genome profiling-based mutation assay (GPMA). This consists of two steps; (i) Escherichia coli culture in the medium with/without mutagens and (ii) Genome profiling (GP) method (an integrated method of random PCR, temperature gradient gel electrophoresis and computer-aided normalization). Owing to high sensitivity of this method, very low concentration of mutagens in tap water could be directly detected without introducing burdensome concentration processes, enabling rapid measurement of low concentration samples. Less expectedly, all of the tap waters tested (22 samples) were shown to be significantly mutagenic while mineral waters were not. Resultantly, this article informs two facts that the GPMA method is competent to measure the mutagenicity of waters directly and the experimental results supported the former reports that the city tap waters contain very low level of mutagenicity reagent trihalomethanes. © The Authors 2014. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  4. Heterogeneous Reactions of Limonene on Mineral Dust: Impacts of Adsorbed Water and Nitric Acid.

    PubMed

    Lederer, Madeline R; Staniec, Allison R; Coates Fuentes, Zoe L; Van Ry, Daryl A; Hinrichs, Ryan Z

    2016-12-08

    Biogenic volatile organic compounds (BVOCs), including the monoterpene limonene, are a major source of secondary organic aerosol (SOA). While gas-phase oxidation initiates the dominant pathway for BVOC conversion to SOA, recent studies have demonstrated that biogenic hydrocarbons can also directly react with acidic droplets. To investigate whether mineral dust may facilitate similar reactive uptake of biogenic hydrocarbons, we studied the heterogeneous reaction of limonene with mineral substrates using condensed-phase infrared spectroscopy and identified the formation of irreversibly adsorbed organic products. For kaolinite, Arizona Test Dust, and silica at 30% relative humidity, GC-MS identified limonene-1,2-diol as the dominant product with total organic surface concentrations on the order of (3-5) × 10 18 molecules m -2 . Experiments with 18 O-labeled water support a mechanism initiated by oxidation of limonene by surface redox sites forming limonene oxide followed by water addition to the epoxide to form limonenediol. Limonene uptake on α-alumina, γ-alumina, and montmorillonite formed additional products in high yield, including carveol, carvone, limonene oxide, and α-terpineol. To model tropospheric processing of mineral aerosol, we also exposed each mineral substrate to gaseous nitric acid prior to limonene uptake and identified similar surface adsorbed products that were formed at rates 2 to 5 times faster than without nitrate coatings. The initial rate of reaction was linearly dependent on gaseous limonene concentration between 5 × 10 12 and 5 × 10 14 molecules cm -3 (0.22-20.5 ppm) consistent with an Eley-Rideal-type mechanism in which gaseous limonene reacts directly with reactive surface sites. Increasing relative humidity decreased the amount of surface adsorbed products indicating competitive adsorption of surface adsorbed water. Using a laminar flow tube reactor we measured the uptake coefficient for limonene on kaolinite at 25% RH to range from

  5. Effects of water-alcohol binary solvents on the thermochemical characteristics of L-tryptophane dissolution at 298.15 K

    NASA Astrophysics Data System (ADS)

    Badelin, V. G.; Smirnov, V. I.

    2013-01-01

    The enthalpies of L-tryptophane solution in water-methanol, water-ethanol, water-1-propanol, and water-2-propanol mixtures at alcohol concentrations of x 2 = 0-0.4 mole fractions were measured by calorimetry. The standard enthalpies of L-tryptophane solution (Δsol H ∘) and transfer (Δtr H ∘) from water to the binary solvent were calculated. The influence of the composition of the water-alcohol mixture and the structure and properties of L-tryptophane on the enthalpy characteristics of the latter was considered. The enthalpy coefficients of pair interactions ( h xy ) of L-tryptophane with alcohol molecules were calculated. The coefficients were positive and increased in the series: methanol (MeOH), ethanol (EtOH), 1-propanol (1-PrOH), and 2-propanol (2-PrOH). The solution and transfer enthalpies of L-tryptophane were compared with those of aliphatic amino acids (glycine, L-threonine, DL-alanine, L-valine, and L-phenylalanine) in similar binary solvents.

  6. Experiment and simulation study on the effects of cement minerals on the water-rock-CO2 interaction during CO2 geological storage

    NASA Astrophysics Data System (ADS)

    Liu, N.; Cheng, J.

    2016-12-01

    The CO2 geological storage is one of the most promising technology to mitigate CO2 emission. The fate of CO2 underground is dramatically affected by the CO2-water-rock interaction, which are mainly dependent on the initial aquifer mineralogy and brine components. The cement minerals are common materials in sandstone reservoir but few attention has been paid for its effects on CO2-water-rock interaction. Five batch reactions, in which 5% cement minerals were assigned to be quartz, calcite, dolomite, chlorite and Ca-montmorillonite, respectively, were conducted to understanding the cement minerals behaviors and its corresponding effects on the matrix minerals alterations during CO2 geological storage. Pure mineral powders were selected to mix and assemble the 'sandstone rock' with different cement components meanwhile keeping the matrix minerals same for each group as 70% quartz, 20% K-feldspar and 5% albite. These `rock' reacted with 750ml deionized water and CO2 under 180° and 18MPa for 15 days, during which the water chemistry evolution and minerals surface micromorphology changes has been monitored. The minerals saturation indexes calculation and phase diagram as well as the kinetic models were made by PHREEQC to uncover the minerals reaction paths. The experiment results indicated that the quartz got less eroded, on the contrary, K-feldspar and albite continuously dissolved to favor the gibbsite and kaolinite precipitations. The carbonates cement minerals quickly dissolved to reach equilibrium with the pH buffered and in turn suppressed the alkali feldspar dissolutions. No carbonates minerals precipitations occurred until the end of reactions for all groups. The simulation results were basically consistent with the experiment record but failed to simulate the non-stoichiometric reactions and the minerals kinetic rates seemed underestimated at the early stage of reactions. The cement minerals significantly dominated the reaction paths during CO2 geological

  7. Aerobic and anaerobic degradation and mineralization of 14C-chitin by water column and sediment inocula of the York River estuary, Virginia.

    PubMed Central

    Boyer, J N

    1994-01-01

    Potential rates of chitin degradation (Cd) and mineralization (Cm) by estuarine water and sediment bacteria were measured as a function of inoculum source, temperature, and oxygen condition. In the water column inoculum, 88 to 93% of the particulate chitin was mineralized to CO2 with no apparent lag between degradation and mineralization. No measurable dissolved pool of radiolabel was found in the water column. For the sediment inocula, 70 to 90% of the chitin was degraded while only 55 to 65% was mineralized to CO2. 14C label recoveries in the dissolved pool were 19 to 21% for sand, 17 to 24% in aerobic mud, and 12 to 21% for the anaerobic mud. This uncoupling between degradation and mineralization occurred in all sediment inocula. More than 98% of the initial 14C-chitin was recovered in the three measured fractions. The highest Cd and Cm values, 30 and 27% day-1, occurred in the water column inoculum at 25 degrees C. The lowest Cd and Cm values were found in the aerobic and anaerobic mud inocula incubated at 15 degrees C. Significant differences in Cd and Cm values among water column and sediment inocula as well as between temperature treatments were evident. An increased incubation temperature resulted in shorter lag times before the onset of chitinoclastic bacterial growth, degradation, and mineralization and resulted in apparent Q10 values of 1.1 for water and 1.3 to 2.1 for sediment inocula. It is clear that chitin degradation and mineralization occur rapidly in the estuary and that water column bacteria may be more important in this process than previously acknowledged. PMID:8117075

  8. Low-carbon, low-water scenarios with life cycle water factors for ES&T paper

    EPA Pesticide Factsheets

    The dataset includes all data used in the creation of figures and graphs in the paper: Scenarios for low carbon and low water electric power plant operations: implications for upstream water use. Data includes regional electricity mixes, full life cycle water use, and water use for each life cycle stage. These encompass a range of scenarios out to 2050, and should not be used as predictions, forecasts or official baselines. The scenarios and results are for research purposes only, and do not represent current or future U.S. EPA policies or regulations.This dataset is associated with the following publication:Dodder , R., J. Barnwell , and W. Yelverton. Scenarios for low carbon and low water electric power plant operations: implications for upstream water use. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 50(21): 11460-11470, (2016).

  9. Molecular simulation of excess isotherm and excess enthalpy change in gas-phase adsorption.

    PubMed

    Do, D D; Do, H D; Nicholson, D

    2009-01-29

    We present a new approach to calculating excess isotherm and differential enthalpy of adsorption on surfaces or in confined spaces by the Monte Carlo molecular simulation method. The approach is very general and, most importantly, is unambiguous in its application to any configuration of solid structure (crystalline, graphite layer or disordered porous glass), to any type of fluid (simple or complex molecule), and to any operating conditions (subcritical or supercritical). The behavior of the adsorbed phase is studied using the partial molar energy of the simulation box. However, to characterize adsorption for comparison with experimental data, the isotherm is best described by the excess amount, and the enthalpy of adsorption is defined as the change in the total enthalpy of the simulation box with the change in the excess amount, keeping the total number (gas + adsorbed phases) constant. The excess quantities (capacity and energy) require a choice of a reference gaseous phase, which is defined as the adsorptive gas phase occupying the accessible volume and having a density equal to the bulk gas density. The accessible volume is defined as the mean volume space accessible to the center of mass of the adsorbate under consideration. With this choice, the excess isotherm passes through a maximum but always remains positive. This is in stark contrast to the literature where helium void volume is used (which is always greater than the accessible volume) and the resulting excess can be negative. Our definition of enthalpy change is equivalent to the difference between the partial molar enthalpy of the gas phase and the partial molar enthalpy of the adsorbed phase. There is no need to assume ideal gas or negligible molar volume of the adsorbed phase as is traditionally done in the literature. We illustrate this new approach with adsorption of argon, nitrogen, and carbon dioxide under subcritical and supercritical conditions.

  10. On the Enthalpy and Entropy of Point Defect Formation in Crystals

    NASA Astrophysics Data System (ADS)

    Kobelev, N. P.; Khonik, V. A.

    2018-03-01

    A standard way to determine the formation enthalpy H and entropy S of point defect formation in crystals consists in the application of the Arrhenius equation for the defect concentration. In this work, we show that a formal use of this method actually gives the effective (apparent) values of these quantities, which appear to be significantly overestimated. The underlying physical reason lies in temperature-dependent formation enthalpy of the defects, which is controlled by temperature dependence of the elastic moduli. We present an evaluation of the "true" H- and S-values for aluminum, which are derived on the basis of experimental data by taking into account temperature dependence of the formation enthalpy related to temperature dependence of the elastic moduli. The knowledge of the "true" activation parameters is needed for a correct calculation of the defect concentration constituting thus an issue of major importance for different fundamental and application issues of condensed matter physics and chemistry.

  11. Ionic liquids. Combination of combustion calorimetry with high-level quantum chemical calculations for deriving vaporization enthalpies.

    PubMed

    Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas; Schick, Christoph

    2008-07-10

    In this work, the molar enthalpies of formation of the ionic liquids [C2MIM][NO3] and [C4MIM][NO3] were measured by means of combustion calorimetry. The molar enthalpy of fusion of [C2MIM][NO3] was measured using differential scanning calorimetry. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the G3MP2 theory. We have used a combination of traditional combustion calorimetry with modern high-level ab initio calculations in order to obtain the molar enthalpies of vaporization of a series of the ionic liquids under study.

  12. A flow calorimeter for determining combustion efficiency from residual enthalpy of exhaust gases

    NASA Technical Reports Server (NTRS)

    Evans, Albert; Hibbard, Robert R

    1954-01-01

    A flow calorimeter for determining the combustion efficiency of turbojet and ram-jet combustors from measurement of the residual enthalpy of combustion of the exhaust gas is described. Briefly, the calorimeter catalytically oxidizes the combustible constituents of exhaust-gas samples, and the resultant temperature rise is measured. This temperature rise is related to the residual enthalpy of combustion of the sample by previous calibration of the calorimeter. Combustion efficiency can be calculated from a knowledge of the residual enthalpy of the exhaust gas and the combustor input enthalpy. An accuracy of +-0.2 Btu per cubic foot was obtained with prepared fuel-air mixtures, and the combustion efficiencies of single turbojet combustors measured by both the flow-calorimeter and heat-balance methods compared within 3 percentage units. Flow calorimetry appears to be a suitable method for determining combustion efficiencies at high combustor temperatures where ordinary thermocouples cannot be used. The method is fundamentally more accurate than heat-balance methods at high combustion efficiencies and can be used to verify near-100-percent efficiency data.

  13. Bacteriological quality and risk assessment of the imported and domestic bottled mineral water sold in Fiji.

    PubMed

    Zeenat, A; Hatha, A A M; Viola, L; Vipra, K

    2009-12-01

    Considering the popularity of bottled mineral water among indigenous Fijians and tourists alike, a study was carried out to determine the bacteriological quality of different bottled waters. A risk assessment was also carried out. Seventy-five samples of bottled mineral water belonging to three domestic brands and 25 samples of one imported brand were analysed for heterotrophic plate count (HPC) bacteria and faecal coliforms. HPC counts were determined at 22 degrees C and 37 degrees C using R2A medium and a membrane filtration technique was used to determine the faecal coliform (FC) load in 100 ml of water on mFC agar. Between 28 and 68% of the samples of the various domestic brands failed to meet the WHO standard of 100 colony forming units (cfu) per 100 ml at 22 degrees C and 7% of these also tested positive for faecal coliforms. All imported bottled mineral water samples were within WHO standards. A risk assessment of the HPC bacteria was carried out in terms of beta haemolytic activity and antibiotic resistance. More than 50% of the isolates showed beta haemolytic activity and were multi-drug resistant. While the overall quality of the product was generally good, there is a need to enforce stringent quality standards for the domestic bottlers to ensure the safety of consumers.

  14. [Balneotherapeutics of non-alcoholic fatty liver disease with the use of the Essentuki-type drinking mineral waters].

    PubMed

    Fedorova, T E; Efimenko, N V; Kaĭsinova, A S

    2012-01-01

    The objective of the present work was to estimate the effectiveness of combined spa-and-resort treatment with the use of the Essentuki-type drinking mineral waters for the patients presenting with non-alcoholic fatty liver disease. A total of 40 patients presening with non-alcoholic fatty liver disease (NOFLD) were available for the examination. The study has demonstrated positive dynamics of clinical symptoms and results of liver functional tests, characteristics of intrahepatic dynamics, lipid metabolism, antioxidant hemostais, and the hormonal status of the patients with non-alcoholic fatty liver disease. The intake of the Essentuki-type drinking mineral waters promoted normalization of adiponectin and leptin levels in conjunction with the reduction in the degree of insulin resistance, i.e., the key pathogenetic factors responsible for hepatic steatosis and non-alcoholic steatohepatitis. It is concluded that the Essentuki-type drinking mineral waters may be recommended for the inclusion in the combined treatment and prevention of the progression of non-alcoholic fatty liver disease.

  15. Borate-polyol complexes in aqueous solution: determination of enthalpies by thermometric titrimetry.

    PubMed

    Aruga, R

    1985-06-01

    Enthalpies for the reaction of borate with 1,2-ethanediol, 1,2-propanediol, 1,2,3-propanetriol and d-mannitol have been determined by thermometric titrimetry. From these enthalpies and equilibrium constants taken from the literature, corresponding entropies have been calculated. The data refer to aqueous solutions at 25 degrees and I = 1.0M (NaNO(3)). The results indicate reasons for the differences in the stabilities of the complexes.

  16. A general structure-property relationship to predict the enthalpy of vaporisation at ambient temperatures.

    PubMed

    Oberg, T

    2007-01-01

    The vapour pressure is the most important property of an anthropogenic organic compound in determining its partitioning between the atmosphere and the other environmental media. The enthalpy of vaporisation quantifies the temperature dependence of the vapour pressure and its value around 298 K is needed for environmental modelling. The enthalpy of vaporisation can be determined by different experimental methods, but estimation methods are needed to extend the current database and several approaches are available from the literature. However, these methods have limitations, such as a need for other experimental results as input data, a limited applicability domain, a lack of domain definition, and a lack of predictive validation. Here we have attempted to develop a quantitative structure-property relationship (QSPR) that has general applicability and is thoroughly validated. Enthalpies of vaporisation at 298 K were collected from the literature for 1835 pure compounds. The three-dimensional (3D) structures were optimised and each compound was described by a set of computationally derived descriptors. The compounds were randomly assigned into a calibration set and a prediction set. Partial least squares regression (PLSR) was used to estimate a low-dimensional QSPR model with 12 latent variables. The predictive performance of this model, within the domain of application, was estimated at n=560, q2Ext=0.968 and s=0.028 (log transformed values). The QSPR model was subsequently applied to a database of 100,000+ structures, after a similar 3D optimisation and descriptor generation. Reliable predictions can be reported for compounds within the previously defined applicability domain.

  17. Endocrine disruptors in bottled mineral water: total estrogenic burden and migration from plastic bottles.

    PubMed

    Wagner, Martin; Oehlmann, Jörg

    2009-05-01

    Food consumption is an important route of human exposure to endocrine-disrupting chemicals. So far, this has been demonstrated by exposure modeling or analytical identification of single substances in foodstuff (e.g., phthalates) and human body fluids (e.g., urine and blood). Since the research in this field is focused on few chemicals (and thus missing mixture effects), the overall contamination of edibles with xenohormones is largely unknown. The aim of this study was to assess the integrated estrogenic burden of bottled mineral water as model foodstuff and to characterize the potential sources of the estrogenic contamination. In the present study, we analyzed commercially available mineral water in an in vitro system with the human estrogen receptor alpha and detected estrogenic contamination in 60% of all samples with a maximum activity equivalent to 75.2 ng/l of the natural sex hormone 17beta-estradiol. Furthermore, breeding of the molluskan model Potamopyrgus antipodarum in water bottles made of glass and plastic [polyethylene terephthalate (PET)] resulted in an increased reproductive output of snails cultured in PET bottles. This provides first evidence that substances leaching from plastic food packaging materials act as functional estrogens in vivo. Our results demonstrate a widespread contamination of mineral water with xenoestrogens that partly originates from compounds leaching from the plastic packaging material. These substances possess potent estrogenic activity in vivo in a molluskan sentinel. Overall, the results indicate that a broader range of foodstuff may be contaminated with endocrine disruptors when packed in plastics.

  18. Opportunistic pathogens and elements of the resistome that are common in bottled mineral water support the need for continuous surveillance.

    PubMed

    Falcone-Dias, Maria Fernanda; Centrón, Daniela; Pavan, Fernando; Moura, Adriana Candido da Silva; Naveca, Felipe Gomes; de Souza, Victor Costa; Farache Filho, Adalberto; Leite, Clarice Queico Fujimura

    2015-01-01

    Several differences concerning bacterial species, opportunistic pathogens, elements of the resistome as well as variations concerning the CFU/mL counts were identified in some of the five most marketed bottled mineral water from Araraquara city, São Paulo, Brazil. Two out of five brands tested were confirmed as potential source of opportunistic pathogens, including Mycobacterium gordonae, Ralstonia picketti and Burkholderia cepacia complex (Bcc). A total of one hundred and six isolates were recovered from four of these bottled mineral water brands. Betaproteobacteria was predominant followed by Alphaproteobacteria, Gammaproteobacteria and Firmicutes. Ninety percent of the bacteria isolated demonstrated resistance to seventeen of the nineteen antimicrobials tested. These antimicrobials included eight different classes, including 3rd and 4th generation cephalosporins, carbapenems and fluoroquinolones. Multidrug resistant bacteria were detected for fifty-nine percent of isolates in three water brands at counts up to 103 CFU/ml. Of major concern, the two bottled mineral water harboring opportunistic pathogens were also source of elements of the resistome that could be directly transferred to humans. All these differences found among brands highlight the need for continuous bacteriological surveillance of bottled mineral water.

  19. Opportunistic Pathogens and Elements of the Resistome that Are Common in Bottled Mineral Water Support the Need for Continuous Surveillance

    PubMed Central

    Falcone-Dias, Maria Fernanda; Centrón, Daniela; Pavan, Fernando; Moura, Adriana Candido da Silva; Naveca, Felipe Gomes; de Souza, Victor Costa; Farache Filho, Adalberto; Leite, Clarice Queico Fujimura

    2015-01-01

    Several differences concerning bacterial species, opportunistic pathogens, elements of the resistome as well as variations concerning the CFU/mL counts were identified in some of the five most marketed bottled mineral water from Araraquara city, São Paulo, Brazil. Two out of five brands tested were confirmed as potential source of opportunistic pathogens, including Mycobacterium gordonae, Ralstonia picketti and Burkholderia cepacia complex (Bcc). A total of one hundred and six isolates were recovered from four of these bottled mineral water brands. Betaproteobacteria was predominant followed by Alphaproteobacteria, Gammaproteobacteria and Firmicutes. Ninety percent of the bacteria isolated demonstrated resistance to seventeen of the nineteen antimicrobials tested. These antimicrobials included eight different classes, including 3rd and 4th generation cephalosporins, carbapenems and fluoroquinolones. Multidrug resistant bacteria were detected for fifty-nine percent of isolates in three water brands at counts up to 103 CFU/ml. Of major concern, the two bottled mineral water harboring opportunistic pathogens were also source of elements of the resistome that could be directly transferred to humans. All these differences found among brands highlight the need for continuous bacteriological surveillance of bottled mineral water. PMID:25803794

  20. Determination of 17O-excess of terrestrial silicate/oxide minerals with respect to Vienna Standard Mean Ocean Water (VSMOW).

    PubMed

    Tanaka, Ryoji; Nakamura, Eizo

    2013-01-30

    Oxygen triple isotope compositions give key information for understanding physical processes during isotopic fractionation between the geo-, hydro-, bio-, and atmosphere. For detailed discussion of these topics, it is necessary to determine precise (17)O-excess values of terrestrial silicate/oxide minerals with respect to Vienna Standard Mean Ocean Water (VSMOW). Water was fluorinated in an electrically heated Ni-metal tube into which water and BrF(5) were loaded for the quantitative extraction of oxygen. Silicate/oxide minerals were fluorinated by heating with a CO(2) laser in an atmosphere of BrF(5). The extracted oxygen was purified and isotope ratios of the oxygen triple isotope compositions were determined using a Finnigan MAT253 isotope ratio mass spectrometer. The oxygen triple isotope compositions of meteoric water and terrestrial silicate/oxide minerals fall on statistically distinguishable fractionation lines, defined as [ln(δ(17)O + 1) = λln(δ(18) O + 1) + Δ], where λ and Δ correspond to the slope and intercept, respectively. The fractionation line for meteoric water has λ = 0.5285 ± 0.0005 and Δ = 0.03 ± 0.02‰ and for terrestrial silicate/oxide minerals has λ = 0.5270 ± 0.0005 and Δ = -0.070 ± 0.005‰, at the 95% confidence limit. All the analyzed terrestrial silicate/oxide minerals including internationally accepted reference materials (NBS-28, UWG-2, and San Carlos olivine) have a negative (17)O-excess with respect to VSMOW. We propose that it is necessary to specify if the determined δ(17)O values of terrestrial and extraterrestrial samples are expressed as the difference from VSMOW or the terrestrial silicate mineral-corrected value. Copyright © 2012 John Wiley & Sons, Ltd.

  1. From Carbonatite to Ikaite: How high-T carbonates are transformed into low-T carbonate minerals in SW Greenland

    NASA Astrophysics Data System (ADS)

    Stockmann, G. J.; Tollefsen, E.; Ranta, E.; Skelton, A.; Sturkell, E.; Lundqvist, L.

    2015-12-01

    The 1300 Ma Grønnedal-Íka igneous complex in southwest Greenland comprises nepheline syenites and carbonatites. It belongs to a suite of intrusions formed 1300-1100 Ma ago referred to as the Gardar period. In modern time (the last ca. 8000 years), fluid-rock interactions involving the nepheline syenites and carbonatites gives rise to about one thousand submarine columns made of the rare low-T mineral ikaite (CaCO3x6H2O). The columns are found in a shallow, narrow fjord named Ikka Fjord and their distribution clearly follows the outcrop of the Grønnedal-Íka complex. When meteoric water percolates through the highly fractured complex, a sodium carbonate solution of pH 10 is formed through hitherto unknown fluid-rock reactions. This basic solution seeps up through fractures at the bottom of Ikka Fjord and when mixed with seawater, the mineral ikaite is formed. As the seepage water has a lower density than seawater, there is an upwards flow that creates columns. What is peculiar about ikaite is its limited stability making it unstable above +6 °C. Isotopic studies of ikaite reveal a seawater origin for the Ca2+ ions, and the carbonatite being the most likely source for the CO32- ions. The carbonatite is mainly of søvite composition (CaCO3) with high contents of siderite and ankerite in certain areas. The nepheline syenites contain Na,K-rich minerals like nepheline, alkali-feldspar, aegirine-augite, katophorite and biotite. Nepheline is mainly replaced by muscovite, and aegirine-augite partly by chlorite, which could release sodium into solution. A dolerite dyke of unknown age prompted extensive mineralization of magnetite by activating hydrothermal fluid convection. The fluid interacted with the carbonatite, replacing siderite and ankerite by magnetite and later hematite. In a newly launched project at Stockholm University, we are trying to unravel the chemical reactions taking place inside the Grønnedal-Íka igneous complex leading to the formation of the

  2. Measurement of natural radionuclides in Malaysian bottled mineral water and consequent health risk estimation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Priharti, W.; Samat, S. B.; Yasir, M. S.

    2015-09-25

    The radionuclides of {sup 226}Ra, {sup 232}Th and {sup 40}K were measured in ten mineral water samples, of which from the radioactivity obtained, the ingestion doses for infants, children and adults were calculated and the cancer risk for the adult was estimated. Results showed that the calculated ingestion doses for the three age categories are much lower than the average worldwide ingestion exposure of 0.29 mSv/y and the estimated cancer risk is much lower than the cancer risk of 8.40 × 10{sup −3} (estimated from the total natural radiation dose of 2.40 mSv/y). The present study concludes that the bottledmore » mineral water produced in Malaysia is safe for daily human consumption.« less

  3. Profiling contents of water-soluble metabolites and mineral nutrients to evaluate the effects of pesticides and organic and chemical fertilizers on tomato fruit quality.

    PubMed

    Watanabe, Masami; Ohta, Yuko; Licang, Sun; Motoyama, Naoki; Kikuchi, Jun

    2015-02-15

    In this study, the contents of water-soluble metabolites and mineral nutrients were measured in tomatoes cultured using organic and chemical fertilizers, with or without pesticides. Mineral nutrients and water-soluble metabolites were determined by inductively coupled plasma-atomic emission spectrometry and (1)H nuclear magnetic resonance spectrometry, respectively, and results were analysed by principal components analysis (PCA). The mineral nutrient and water-soluble metabolite profiles differed between organic and chemical fertilizer applications, which accounted for 88.0% and 55.4%, respectively, of the variation. (1)H-(13)C-hetero-nuclear single quantum coherence experiments identified aliphatic protons that contributed to the discrimination of PCA. Pesticide application had little effect on mineral nutrient content (except Fe and P), but affected the correlation between mineral nutrients and metabolites. Differences in the content of mineral nutrients and water-soluble metabolites resulting from different fertilizer and pesticide applications probably affect tomato quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. The role of mineral elements and other chemical compounds used in balneology: data from double-blind randomized clinical trials

    NASA Astrophysics Data System (ADS)

    Morer, Carla; Roques, Christian-François; Françon, Alain; Forestier, Romain; Maraver, Francisco

    2017-12-01

    The aims of this study were to conduct a systematic literature review on balneotherapy about the specific therapeutic role of mineral elements and other chemical compounds of mineral waters and derivate peloids/muds and to discuss the study methods used to evaluate it (in musculoskeletal conditions). We searched Medline by PubMed using the following key words: "spa therapy" "balneotherapy" "mud" "peloid" "mud pack Therapy" in combination with "randomized controlled trial" "double blind trial." We also reviewed the reference list of articles retrieved by the Medline search. We selected the double-blind randomized clinical trials that assessed the effects of mineral water or mud treatments compared to tap water, attenuated peloid/mud therapy or similar treatments without the specific minerals or chemical compounds of the treatment group ("non-mineral"). We evaluated the internal validity and the quality of the statistical analysis of these trials. The final selection comprised 27 double-blind randomized clinical trials, 20 related to rheumatology. A total of 1118 patients with rheumatological and other musculoskeletal diseases were evaluated in these studies: 552 of knee osteoarthritis, 47 of hand osteoarthritis, 147 chronic low back pain, 308 of reumathoid arthritis, and 64 of osteoporosis; 293 of these participants were assigned to the experimental groups of knee osteoarthritis, 24 in hand osteoarthritis, 82 of low back pain, 152 with reumathoid arthritis, and 32 with osteoporosis. They were treated with mineral water baths and/or mud/peloid (with or without other forms of treatment, like physical therapy, exercise…). The rest were allocated to the control groups; they received mainly tap water and/or "non-mineral" mud/peloid treatments. Mineral water or mud treatments had better and longer improvements in pain, function, quality of life, clinical parameters, and others in some rheumatologic diseases (knee and hand osteoarthritis, chronic low back pain

  5. The role of mineral elements and other chemical compounds used in balneology: data from double-blind randomized clinical trials.

    PubMed

    Morer, Carla; Roques, Christian-François; Françon, Alain; Forestier, Romain; Maraver, Francisco

    2017-12-01

    The aims of this study were to conduct a systematic literature review on balneotherapy about the specific therapeutic role of mineral elements and other chemical compounds of mineral waters and derivate peloids/muds and to discuss the study methods used to evaluate it (in musculoskeletal conditions). We searched Medline by PubMed using the following key words: "spa therapy" "balneotherapy" "mud" "peloid" "mud pack Therapy" in combination with "randomized controlled trial" "double blind trial." We also reviewed the reference list of articles retrieved by the Medline search. We selected the double-blind randomized clinical trials that assessed the effects of mineral water or mud treatments compared to tap water, attenuated peloid/mud therapy or similar treatments without the specific minerals or chemical compounds of the treatment group ("non-mineral"). We evaluated the internal validity and the quality of the statistical analysis of these trials. The final selection comprised 27 double-blind randomized clinical trials, 20 related to rheumatology. A total of 1118 patients with rheumatological and other musculoskeletal diseases were evaluated in these studies: 552 of knee osteoarthritis, 47 of hand osteoarthritis, 147 chronic low back pain, 308 of reumathoid arthritis, and 64 of osteoporosis; 293 of these participants were assigned to the experimental groups of knee osteoarthritis, 24 in hand osteoarthritis, 82 of low back pain, 152 with reumathoid arthritis, and 32 with osteoporosis. They were treated with mineral water baths and/or mud/peloid (with or without other forms of treatment, like physical therapy, exercise…). The rest were allocated to the control groups; they received mainly tap water and/or "non-mineral" mud/peloid treatments. Mineral water or mud treatments had better and longer improvements in pain, function, quality of life, clinical parameters, and others in some rheumatologic diseases (knee and hand osteoarthritis, chronic low back pain

  6. Lower Serum Creatinine Is Associated with Low Bone Mineral Density in Subjects without Overt Nephropathy

    PubMed Central

    Huh, Ji Hye; Choi, Soo In; Lim, Jung Soo; Chung, Choon Hee; Shin, Jang Yel; Lee, Mi Young

    2015-01-01

    Background Low skeletal muscle mass is associated with deterioration of bone mineral density. Because serum creatinine can serve as a marker of muscle mass, we evaluated the relationship between serum creatinine and bone mineral density in an older population with normal renal function. Methods Data from a total of 8,648 participants (4,573 men and 4,075 postmenopausal women) aged 45–95 years with an estimated glomerular filtration rate >60 ml/min/1.73 m2 were analyzed from the Fourth Korea National Health and Nutrition Examination Survey (2008–2010). Bone mineral density (BMD) and appendicular muscle mass (ASM) were measured using dual-energy X-ray absorptiometry. Receiver operating characteristic curve analysis revealed that the cut points of serum creatinine for sarcopenia were below 0.88 mg/dl in men and 0.75 mg/dl in women. Subjects were divided into two groups: low creatinine and upper normal creatinine according to the cut point value of serum creatinine for sarcopenia. Results In partial correlation analysis adjusted for age, serum creatinine was positively associated with both BMD and ASM. Subjects with low serum creatinine were at a higher risk for low BMD (T-score ≤ –1.0) at the femur neck, total hip and lumbar spine in men, and at the total hip and lumbar spine in women after adjustment for confounding factors. Each standard deviation increase in serum creatinine was significantly associated with reduction in the likelihood of low BMD at the total hip and lumbar spine in both sexes (men: odds ratio (OR) = 0.84 [95% CI = 0.74−0.96] at the total hip, OR = 0.8 [95% CI = 0.68−0.96] at the lumbar spine; women: OR = 0.83 [95% CI = 0.73–0.95] at the total hip, OR=0.81 [95% CI = 0.67–0.99] at the lumbar spine). Conclusions Serum creatinine reflected muscle mass, and low serum creatinine was independently associated with low bone mineral density in subjects with normal kidney function. PMID:26207750

  7. Differential heat of adsorption of water vapor on silicified microcrystalline cellulose (SMCC): an investigation using isothermal microcalorimetry.

    PubMed

    Qian, Ken K; Bogner, Robin H

    2011-01-01

    A novel dual-shaft configuration in isothermal microcalorimetry was developed to study the interaction of water vapor with pharmaceutical excipients. An instrument performance test is suggested to validate the experimental data. Reliable experimental results can be collected using a single perfusion shaft; however, there was limitation of the dual-shaft configuration, which resulted deviation in the experimental results. A periodic performance test is recommended. Silicified microcrystalline cellulose (SMCC) was used as a model system to study the interaction using the dual-shaft method. Enthalpy of water vapor adsorption on SMCC was determined and compared to literature data. The data collected using the dual-shaft configuration did not reflect the actual physical system. The deviation was most likely due to the lack of flow control caused by viscous resistance. The enthalpy of adsorption was then calculated using isothermal microcalorimetry coupled with a dynamic vapor sorption apparatus. The results, -55 kJ/mol at low relative humidity (RH) to -22 kJ/mol at high RH, were consistent with the physical phenomenon of water vapor adsorption. Enthalpy of adsorption showed surface heterogeneity of SMCC and suggested multilayer condensation of water at approximately 60% RH. However, at high RH, the results showed the moisture-excipient interaction can be more complex than the proposed mechanism.

  8. Hydrodesulfurization and hydrodenitrogenation catalysts obtained from coal mineral matter

    DOEpatents

    Liu, Kindtoken H. D.; Hamrin, Jr., Charles E.

    1982-01-01

    A hydrotreating catalyst is prepared from coal mineral matter obtained by low temperature ashing coals of relatively low bassanite content by the steps of: (a) depositing on the low temperature ash 0.25-3 grams of an iron or nickel salt in water per gram of ash and drying a resulting slurry; (b) crushing and sizing a resulting solid; and (c) heating the thus-sized solid powder in hydrogen.

  9. Adsorption of Dissolved Gases (CH4, CO2, H2, Noble Gases) by Water-Saturated Smectite Clay Minerals

    NASA Astrophysics Data System (ADS)

    Bourg, I. C.; Gadikota, G.; Dazas, B.

    2016-12-01

    Adsorption of dissolved gases by water-saturated clay minerals plays important roles in a range of fields. For example, gas adsorption in on clay minerals may significantly impact the formation of CH4 hydrates in fine-grained sediments, the behavior of CH4 in shale, CO2 leakage across caprocks of geologic CO2 sequestration sites, H2 leakage across engineered clay barriers of high-level radioactive waste repositories, and noble gas geochemistry reconstructions of hydrocarbon migration in the subsurface. Despite its importance, the adsorption of gases on clay minerals remains poorly understood. For example, some studies have suggested that clay surfaces promote the formation of CH4 hydrates, whereas others indicate that clay surfaces inhibit the formation of CH4 hydrates. Here, we present molecular dynamics (MD) simulations of the adsorption of a range of gases (CH4, CO2, H2, noble gases) on clay mineral surfaces. Our results indicate that the affinity of dissolved gases for clay mineral surfaces has a non-monotone dependence on the hydrated radius of the gas molecules. This non-monotone dependence arises from a combination of two effects: the polar nature of certain gas molecules (in particular, CO2) and the templating of interfacial water structure by the clay basal surface, which results in the presence of interfacial water "cages" of optimal size for intermediate-size gas molecules (such as Ne or Ar).

  10. A molecular dynamics study of ambient and high pressure phases of silica: structure and enthalpy variation with molar volume.

    PubMed

    Rajappa, Chitra; Sringeri, S Bhuvaneshwari; Subramanian, Yashonath; Gopalakrishnan, J

    2014-06-28

    Extensive molecular dynamics studies of 13 different silica polymorphs are reported in the isothermal-isobaric ensemble with the Parrinello-Rahman variable shape simulation cell. The van Beest-Kramer-van Santen (BKS) potential is shown to predict lattice parameters for most phases within 2%-3% accuracy, as well as the relative stabilities of different polymorphs in agreement with experiment. Enthalpies of high-density polymorphs - CaCl2-type, α-PbO2-type, and pyrite-type - for which no experimental data are available as yet, are predicted here. Further, the calculated enthalpies exhibit two distinct regimes as a function of molar volume-for low and medium-density polymorphs, it is almost independent of volume, while for high-pressure phases a steep dependence is seen. A detailed analysis indicates that the increased short-range contributions to enthalpy in the high-density phases arise not only from an increased coordination number of silicon but also shorter Si-O bond lengths. Our results indicate that amorphous phases of silica exhibit better optimization of short-range interactions than crystalline phases at the same density while the magnitude of Coulombic contributions is lower in the amorphous phase.

  11. Enthalpic Breakdown of Water Structure on Protein Active-Site Surfaces

    PubMed Central

    Haider, Kamran; Wickstrom, Lauren; Ramsey, Steven; Gilson, Michael K.; Kurtzman, Tom

    2016-01-01

    The principles underlying water reorganization around simple non-polar solutes are well understood and provide the framework for classical hydrophobic effect, whereby water molecules structure themselves around solutes so that they maintain favorable energetic contacts with both the solute and with other water molecules. However, for certain solute surface topographies, water molecules, due to their geometry and size, are unable to simultaneously maintain favorable energetic contacts with both the surface and neighboring water molecules. In this study, we analyze the solvation of ligand-binding sites for six structurally diverse proteins using hydration site analysis and measures of local water structure, in order to identify surfaces at which water molecules are unable to structure themselves in a way that maintains favorable enthalpy relative to bulk water. These surfaces are characterized by a high degree of enclosure, weak solute-water interactions, and surface constraints that induce unfavorable pair interactions between neighboring water molecules. Additionally, we find that the solvation of charged side-chains in an active site generally results in favorable enthalpy but can also lead to pair interactions between neighboring water molecules that are significantly unfavorable relative to bulk water. We find that frustrated local structure can occur not only in apolar and weakly polar pockets, where overall enthalpy tends to be unfavorable, but also in charged pockets, where overall water enthalpy tends to be favorable. The characterization of local water structure in these terms may prove useful for evaluating the displacement of water from diverse protein active-site environments. PMID:27169482

  12. Mineral and water content of A. gigas scales determine local micromechanical properties and energy dissipation mechanisms

    NASA Astrophysics Data System (ADS)

    Troncoso, Omar P.; Gigos, Florian; Torres, Fernando G.

    2017-11-01

    Arapaima gigas scales are natural laminated composite materials made of individual layers with different degrees of mineralization, accompanied of varying mechanical properties. This natural design provides scales with hardness and flexibility, and can serve as a source of inspiration for the development of new layered composites with a hard surface and flexible base. In this paper, we have carried out cyclic micro-indentation tests on both; the internal and the highly mineralized external surface of air dried and wet scales, in order to assess the variation of their local micromechanical properties with regard to the mineral and water content. The load-penetration (P-h) curves showed that creep takes place throughout the application of a constant force during the micro-indentation tests, confirming the time dependent response of A. gigas scales. A model that accounted for the elastic, plastic and viscous responses of the samples was used to fit the experimental results. The penetration depth during loading and creep, as well as the energy dissipated are dependent on the water content. The used model suggests that the viscous response of the internal layer increases with the water content.

  13. Effect of irrigation water salinity on the organic carbon mineralization in soil (laboratory incubation)

    NASA Astrophysics Data System (ADS)

    Mancer, Halima; Bouhoun, Mustapha Daddi

    2018-05-01

    In a laboratory study, the impact of salts on mineralization of organic carbon of soil was examined through the monitoring of the amount of CO2-C released from soil. The soil used was classified as a nonsaline soil which has been irrigated with artificially salinized water, a factorial combination of three types of salts (NaCl, MgCl2, CaCl2) with three levels of electrical conductivities (3, 6, and 9 dS.m-1) was used to assess the Carbon mineralization. The incubation was carried out under aerobic conditions and at a constant temperature of 28 °C during 70 days with moisture adjusted to 2/3 of the field capacity. No significant (P > 0.05) variation in the amount of CO2-C release from soil was observed until day 56 of the incubation, but it was significantly different due to the irrigation with salt solutions during the days: 70 (p ≤ 0.05). The results suggest that the rate of C-CO2 evolution decreased with the increase in water salinity compared to the control. Also this decrease of C-mineralization in the soils irrigated by the salts solutions of NaCl was the greatest compared to the other two salts (CaCl2, and MgCl2). These results suggest that C mineralization depended on the type of salts as well as the duration of incubation.

  14. Occurrence of bisphenol A in surface water, drinking water and plasma from Malaysia with exposure assessment from consumption of drinking water.

    PubMed

    Santhi, V A; Sakai, N; Ahmad, E D; Mustafa, A M

    2012-06-15

    This study investigated the level of bisphenol A (BPA) in surface water used as potable water, drinking water (tap and bottled mineral water) and human plasma in the Langat River basin, Malaysia. BPA was present in 93% of the surface water samples at levels ranging from below limit of quantification (LOQ; 1.3 ng/L) to 215 ng/L while six fold higher levels were detected in samples collected near industrial and municipal sewage treatment plant outlets. Low levels of BPA were detected in most of the drinking water samples. BPA in tap water ranged from 3.5 to 59.8 ng/L with the highest levels detected in samples collected from taps connected to PVC pipes and water filter devices. Bottled mineral water had lower levels of BPA (3.3±2.6 ng/L) although samples stored in poor storage condition had significantly higher levels (11.3±5.3 ng/L). Meanwhile, only 17% of the plasma samples had detectable levels of BPA ranging from 0.81 to 3.65 ng/mL. The study shows that BPA is a ubiquitous contaminant in surface, tap and bottled mineral water. However, exposure to BPA from drinking water is very low and is less than 0.01% of the tolerable daily intake (TDI). Copyright © 2012 Elsevier B.V. All rights reserved.

  15. The Effect of Mars-relevant Minerals on the Water Uptake of Magnesium Perchlorate and Implications for the Near-surface of Mars

    NASA Astrophysics Data System (ADS)

    Primm, Katherine; Gough, Raina; Rivera-Valentin, Edgard G.; Tolbert, Margaret

    2017-10-01

    The water uptake and release by hygroscopic salts such as perchlorate has been well studied in the decade since they were first discovered on the surface of Mars. However, there have been few studies on the effect of the insoluble regolith minerals on this well documented interaction of perchlorate and water vapor. In this work, we investigate the effect that two insoluble Mars-relevant minerals, montmorillonite and Mojave Mars Simulant (MMS), have on the water uptake (deliquescence), ice formation, and recrystallization (efflorescence) of pure magnesium perchlorate. We studied mixtures of equal parts (by mass) magnesium perchlorate hexahydrate and either montmorillonite or MMS. Although montmorillonite and MMS are insoluble minerals that may serve as nuclei for either ice nucleation or salt efflorescence, we find that these minerals did not affect any of the phase transitions of magnesium perchlorate. The salt-mineral mixture behaved like pure magnesium perchlorate in all cases, with stable deliquescence as well as metastable brine supersaturation and supercooling observed. Experiments were performed in both N2 and CO2 atmospheres, with no detectable difference. We use data from the Rover Environmental Monitoring Station instrument on MSL and from the Thermal and Electrical Conductivity Probe instrument on Phoenix, as well as modeling of the shallow subsurface near the rover and lander, to determine the likelihood of liquid water and water ice at Gale Crater and the Phoenix landing site.

  16. Between chemistry, medicine and leisure: Antonio Casares and the study of mineral waters and Spanish spas in the nineteenth century.

    PubMed

    Suay-Matallana, Ignacio

    2016-07-01

    This article considers how chemical analyses were employed not only to study and describe mineral waters, but also to promote new spas, and to reinforce the scientific authority of experts. Scientists, jointly with bath owners, visitors and local authorities, created a significant spa market by transforming rural spaces into social and economic sites. The paper analyses the role developed by the chemist Antonio Casares in the commodification of mineral water in mid-19(th) century Spain. His scientific publications and water analyses put a new economic value on some Spanish mineral waters and rural springs. First the paper explores the relationship between geographic factors, regulation, and spa development in 19(th) century Spain, and considers how scientific work improved the economy of some rural areas. Then the transformation of numerous country springs into spas, and the commodification of baths as places between science and leisure is examined. Finally the location of spas across the borders of medicine and chemistry is shown, together with the complex field operations required to study mineral waters. This paper reveals an intense circulation of knowledge between the field, laboratories and scientific publications, as well as the essential role developed by experts like Casares, who not only contributed to the study of rural springs but also to their economic transformation.

  17. Trace elements and heavy metals in mineral and bottled drinking waters on the Iranian market.

    PubMed

    Hadiani, Mohammad Rasoul; Dezfooli-Manesh, Shirin; Shoeibi, Shahram; Ziarati, Parisa; Mousavi Khaneghah, Amin

    2015-01-01

    A survey of Iranian waters, sampled from 2010 to 2013, is presented. A total of 128 water samples from 42 different brands of bottled mineral and drinking water were collected and analysed for contamination levels of lead (Pb), cadmium (Cd), copper (Cu), arsenic (As) and mercury (Hg). Determinations were performed using a graphite furnace atomic absorption spectrophotometer for Pb, Cd and Cu, a hydride vapour generation as well as an Arsenator digital kit (Wagtech WTD, Tyne and Wear, UK) for As and a direct mercury analyser for Hg. Arsenic concentration in six bottled gaseous mineral samples was higher than the related limit. Regardless of these, mean concentrations of Pb, Cd, Cu, As and Hg in all types of water samples were 4.50 ± 0.49, 1.08 ± 0.09, 16.11 ± 2.77, 5.80 ± 1.63 and 0.52 ± 0.03 µg L⁻¹, respectively. Values obtained for analysed heavy metals in all samples were permissible according to the limits of national and international standards.

  18. A coupled hydrodynamic-hydrochemical modeling for predicting mineral transport in a natural acid drainage system.

    NASA Astrophysics Data System (ADS)

    Zegers Risopatron, G., Sr.; Navarro, L.; Montserrat, S., Sr.; McPhee, J. P.; Niño, Y.

    2017-12-01

    The geochemistry of water and sediments, coupled with hydrodynamic transport in mountainous channels, is of particular interest in central Chilean Andes due to natural occurrence of acid waters. In this paper, we present a coupled transport and geochemical model to estimate and understand transport processes and fate of minerals at the Yerba Loca Basin, located near Santiago, Chile. In the upper zone, water presentes low pH ( 3) and high concentrations of iron, aluminum, copper, manganese and zinc. Acidity and minerals are the consequence of water-rock interactions in hydrothermal alteration zones, rich in sulphides and sulphates, covered by seasonal snow and glaciers. Downstream, as a consequence of neutral to alkaline lateral water contributions (pH >7) along the river, pH increases and concentration of solutes decreases. The mineral transport model has three components: (i) a hydrodynamic model, where we use HEC-RAS to solve 1D Saint-Venant equations, (ii) a sediment transport model to estimate erosion and sedimentation rates, which quantify minerals transference between water and riverbed and (iii) a solute transport model, based on the 1D OTIS model which takes into account the temporal delay in solutes transport that typically is observed in natural channels (transient storage). Hydrochemistry is solved using PHREEQC, a software for speciation and batch reaction. Our results show that correlation between mineral precipitation and dissolution according to pH values changes along the river. Based on pH measurements (and according to literature) we inferred that main minerals in the water system are brochantite, ferrihydrite, hydrobasaluminite and schwertmannite. Results show that our model can predict the transport and fate of minerals and metals in the Yerba Loca Basin. Mineral dissolution and precipitation process occur for limited ranges of pH values. When pH values are increased, iron minerals (schwertmannite) are the first to precipitate ( 2.5

  19. Interactions Between Chlorinated Waste Solvents and Clay Minerals in Low Permeability Subsurface Layers

    NASA Astrophysics Data System (ADS)

    Ayral, D.; Otero-Diaz, M.; Demond, A. H.

    2014-12-01

    Waste organic contaminants stored in low permeability subsurface layers serve as long-term sources for dissolved phase contaminant plumes. These layers may have a different mineralogical make up than the surrounding geologic media; specifically, they may be characterized by a high clay content. Although these layers are often considered inert, interactions may occur between the clay minerals and the waste liquids that may influence transport. Measurements of the basal spacing of Na-montmorillonite in contact with pure chlorinated organic liquids such as trichloroethylene (TCE) showed that it is similar to that with water; however, its basal spacing in contact with waste chlorinated liquids was reduced, leading to cracking. In fact, the basal spacing in contact with the waste chlorinated liquids was closer to that in contact with air than in contact with water. The observation that contact with pure organic liquids did not cause cracking, but contact with chlorinated wastes obtained from the field did, suggests that other components of the waste are critical to the basal spacing reduction process. Screening experiments indicated that the presence of a binary mixture of surfactants, a nonionic and an anionic surfactant, in the chlorinated solvent were necessary to cause the cracking at the same rate and magnitude as the chlorinated wastes obtained from the field. Fourier transform infrared (FT-IR) spectroscopy measurements suggest that the mixture alters the adsorbed water OH-bending band, implying a displacement of adsorbed water. Coupling these results with sorption and x-ray diffraction (XRD) measurements, a hypothesis of component conformation in the clay interlayer space that leads to cracking can be constructed.

  20. Effects of partitioned enthalpy of mixing on glass-forming ability

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Song, Wen-Xiong; Zhao, Shi-Jin, E-mail: shijin.zhao@shu.edu.cn

    2015-04-14

    We explore the inherent reason at atomic level for the glass-forming ability of alloys by molecular simulation, in which the effect of partitioned enthalpy of mixing is studied. Based on Morse potential, we divide the enthalpy of mixing into three parts: the chemical part (Δ E{sub nn}), strain part (Δ E{sub strain}), and non-bond part (Δ E{sub nnn}). We find that a large negative Δ E{sub nn} value represents strong AB chemical bonding in AB alloy and is the driving force to form a local ordered structure, meanwhile the transformed local ordered structure needs to satisfy the condition (Δ E{submore » nn}/2 + Δ E{sub strain}) < 0 to be stabilized. Understanding the chemical and strain parts of enthalpy of mixing is helpful to design a new metallic glass with a good glass forming ability. Moreover, two types of metallic glasses (i.e., “strain dominant” and “chemical dominant”) are classified according to the relative importance between chemical effect and strain effect, which enriches our knowledge of the forming mechanism of metallic glass. Finally, a soft sphere model is established, different from the common hard sphere model.« less

  1. Air-Sea Momentum and Enthalpy Exchange in Coupled Atmosphere-Wave-Ocean Modeling of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Curcic, M.; Chen, S. S.

    2016-02-01

    The atmosphere and ocean are coupled through momentum, enthalpy, and mass fluxes. Accurate representation of these fluxes in a wide range of weather and climate conditions is one of major challenges in prediction models. Their current parameterizations are based on sparse observations in low-to-moderate winds and are not suited for high wind conditions such as tropical cyclones (TCs) and winter storms. In this study, we use the Unified Wave INterface - Coupled Model (UWIN-CM), a high resolution, fully-coupled atmosphere-wave-ocean model, to better understand the role of ocean surface waves in mediating air-sea momentum and enthalpy exchange in TCs. In particular, we focus on the explicit treatment of wave growth and dissipation for calculating atmospheric and oceanic stress, and its role in upper ocean mixing and surface cooling in the wake of the storm. Wind-wave misalignment and local wave disequilibrium result in difference between atmospheric and oceanic stress being largest on the left side of the storm. We find that explicit wave calculation in the coupled model reduces momentum transfer into the ocean by more than 10% on average, resulting in reduced cooling in TC's wake and subsequent weakening of the storm. We also investigate the impacts of sea surface temperature and upper ocean parameterization on air-sea enthalpy fluxes in the fully coupled model. High-resolution UWIN-CM simulations of TCs with various intensities and structure are conducted in this study to better understand the complex TC-ocean interaction and improve the representation of air-sea coupling processes in coupled prediction models.

  2. Clinical improvement of patients with osteoarthritis using thermal mineral water at Szigetvár Spa—results of a randomised double-blind controlled study

    NASA Astrophysics Data System (ADS)

    Hanzel, Adrienn; Horvát, Krisztina; Molics, Bálint; Berényi, Károly; Németh, Balázs; Szendi, Katalin; Varga, Csaba

    2018-02-01

    Since 1966, Szigetvár in Hungary is well recognised as a thermal spa. Many patients suffering from rheumatic diseases are treated with its thermal mineral water. Our objective was to investigate the effects of a 3-week-long outpatient balneotherapy-based rehabilitation program on patients suffering from osteoarthritis of the hips and the knees. During the treatment period, patients received a 30-min underwater jet massage in a bath tub, five times a week. One patient group received jet massage in a bath tub containing mineral water; the other group received the same treatment in tap water. Primary outcomes were measured by range of movement of the involved joints and Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Visual analogue scale (VAS) was applied to measure current severity of pain. Furthermore, quality of life was assessed using the Short Form 36 questionnaire (SF-36). Range of movement (ROM) score, Western Ontario and McMaster University Osteoarthritis Index and visual analogue scale were determined before the first treatment, after the last treatment and 3 months after the last treatment. SF-36 questionnaire was filled in before the first and after the last treatment. Fifty patients (17 male, 33 female mean age 66.7 ± 4.79 years) were enrolled. After randomisation, patients were divided into two groups: tap water n = 24 and mineral water n = 26. Treatment with the thermal mineral water of Szigetvár significantly improved ROM, WOMAC scores, and SF-36-scored quality of life of the patients. Our double-blind study provided evidence for the beneficial health effects of another Hungarian thermal mineral water masking the colour, odour and pH of the tap water and mineral water.

  3. CO2 Driven Mineral Transformations in Fractured Reservoir

    NASA Astrophysics Data System (ADS)

    Schaef, T.

    2015-12-01

    Engineering fracture systems in low permeable formations to increase energy production, accelerate heat extraction, or to enhance injectivity for storing anthropogenic CO2, is a challenging endeavor. To complicate matters, caprocks, essential components of subsurface reservoirs, need to maintain their sealing integrity in this modified subsurface system. Supercritical CO2 (scCO2), a proposed non-aqueous based working fluid, is capable of driving mineral transformations in fracture environments. Water dissolution in scCO2 significantly impacts the reactivity of this fluid, largely due to the development of thin adsorbed H2O films on the surfaces of exposed rocks and minerals. Adsorbed H2O films are geochemically complex microenvironments that host mineral dissolution and precipitation processes that could be tailored to influence overall formation permeability. Furthermore, manipulating the composition of injected CO2 (e.g., moisture content and/or reactive gases such as O2, NOx, or SOx) could stimulate targeted mineral transformations that enhance or sustain reservoir performance. PNNL has developed specialized experimental techniques that can be used to characterize chemical reactions occurring between minerals and pressurized gases. For example, hydration of a natural shale sample (Woodford Shale) has been characterized by an in situ infrared spectroscopic technique as water partitions from the scCO2 onto the shale. Mineral dissolution and carbonate precipitation reactions were tracked by monitoring changes of Si-O and C-O stretching bands, respectively Structural changes indicated expandable clays in the shale such as montmorillonite are intercalated with scCO2, a process not observed with the non-expandable kaolinite component. Extreme scale ab initio molecular dynamics simulations were used in conjunction with model mineral systems to identify the driving force and mechanism of water films. They showed that the film nucleation and formation on minerals is

  4. [The adaptation reactions in hormonal systems to the internal use of mineral waters].

    PubMed

    Polushina, N D

    1991-01-01

    A single intake of mineral water Essentuki 17 by male Wistar rats (n-130, b. w. 180-250 g) leads to stress reactions. It is evident from elevated levels of ACTH, hydrocortisone, leuenkephaline, glucagon and gastrin. Course intake of the water brings about a rise in most of the hormones levels studied. However, single doses of Essentuki 17 inhibit production of hormones in the adrenals, hypophysis, hypothalamus, the system of endogenic opiates. The enhancement of relevant levels are noted in the gastroenteropancreatic system.

  5. Low-temperature water-rock interactions in bedrock aquifers of southern Rhode Island: Results of laboratory simulations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Veeger, A.I.; Moulton, K.L.

    1993-03-01

    The nature of low-temperature chemical reactions occurring in bedrock aquifers of southern Rhode Island was investigated in the laboratory using flow-through columns. Crushed samples of Narragansett Pier Granite (NPG), Scituate Granite Gneiss (SGG), Hope Valley Alaskite Gneiss (HVAG) and Ten Rod Granite Gneiss (TRGG) were placed in flow-through columns. Water was circulated through the columns at a 3 ml/min and maintained at 25 C and at equilibrium with atmospheric carbon dioxide. Samples were collected from the columns at increasing time intervals and were analyzed for pH, conductivity, major cations and anions, and silica. The leachate compositions show that distinctive chemicalmore » differences can be expected in ground water that flows through each of these different rock types. Chemical modeling of the leachate solutions shows that reactions involving plagioclase feldspar (albiteoligoclase), reactive accessory minerals such as sphene, and, to a lesser degree, potassium feldspar and biotite, dominate the solution chemistry, with amorphous oxides and aluminosilicates formed as products of the weathering reactions. Small concentrations of reactive minerals may profoundly affect the composition of the leachate. Batch experiments using mineral separates revealed that the calcium in the NPG leachate was almost entirely attributable to sphene which comprises less than 1% of the rock.« less

  6. Mineral Surface Rearrangement at High Temperatures: Implications for Extraterrestrial Mineral Grain Reactivity.

    PubMed

    King, Helen E; Plümper, Oliver; Putnis, Christine V; O'Neill, Hugh St C; Klemme, Stephan; Putnis, Andrew

    2017-04-20

    Mineral surfaces play a critical role in the solar nebula as a catalytic surface for chemical reactions and potentially acted as a source of water during Earth's accretion by the adsorption of water molecules to the surface of interplanetary dust particles. However, nothing is known about how mineral surfaces respond to short-lived thermal fluctuations that are below the melting temperature of the mineral. Here we show that mineral surfaces react and rearrange within minutes to changes in their local environment despite being far below their melting temperature. Polished surfaces of the rock and planetary dust-forming silicate mineral olivine ((Mg,Fe) 2 SiO 4 ) show significant surface reorganization textures upon rapid heating resulting in surface features up to 40 nm in height observed after annealing at 1200 °C. Thus, high-temperature fluctuations should provide new and highly reactive sites for chemical reactions on nebula mineral particles. Our results also may help to explain discrepancies between short and long diffusion profiles in experiments where diffusion length scales are of the order of 100 nm or less.

  7. Water pollution in relation to mineral exploration: a case study from Alayi-Ovim area of southeastern Nigeria.

    PubMed

    Ibe, Kalu K; Akaolisa, Casmir C Zanders

    2012-05-01

    Water samples from rivers, streams, springs, and shallow wells in Alayi-Ovim area of southeast Nigeria have been analyzed for Pb, Ca, Mg, Fe, Mg, PO(4), NO(3), CO(3), SO(4), Cl, and pH. The analyses were carried out using atomic absorption spectrometer and Hach Direct Reading Equipment. Results of the analyses from the area conform to the WHO (1995) standards for drinking water. However, the results show relative enrichment of Ca, pH, Mg, CO(3), and Cl. Low values were obtained for Fe, SO(4), and NO(3). While the Cl and Pb enrichment in the area north of Alayi-Ovim axis is attributed to proximity to the lead-zinc and chloride-rich formations of the Turonian Eze-Aku and the Albian Asu River; the Ca, Mg, SO(4), and CO(3) enrichment in Southern part of Alayi-Ovim is due to the limestone-bearing Late Maastrichtian Nsukka Formation. Furthermore, the very low values of less than 5 ppm for these characters in water in the central region correlate well with the relatively clean Maastrichtian quartz arenite Ajali Sandstone Formation. The Pb-Zn and Cl incursions into the water system from the Older Albian Asu River/Turonian Eze-Aku Formations in the northern part of Alayi-Ovim area and the leaching of Mg, and Ca into the water system in the Maastrichtian limestone area in the south thus constitute geochemical indices for chemical pollution and mineral exploration for brine and dolomitic limestone in the area.

  8. Enthalpy-based equation of state for highly porous materials employing modified soft sphere fluid model

    NASA Astrophysics Data System (ADS)

    Nayak, Bishnupriya; Menon, S. V. G.

    2018-01-01

    Enthalpy-based equation of state based on a modified soft sphere model for the fluid phase, which includes vaporization and ionization effects, is formulated for highly porous materials. Earlier developments and applications of enthalpy-based approach had not accounted for the fact that shocked states of materials with high porosity (e.g., porosity more than two for Cu) are in the expanded fluid region. We supplement the well known soft sphere model with a generalized Lennard-Jones formula for the zero temperature isotherm, with parameters determined from cohesive energy, specific volume and bulk modulus of the solid at normal condition. Specific heats at constant pressure, ionic and electronic enthalpy parameters and thermal excitation effects are calculated using the modified approach and used in the enthalpy-based equation of state. We also incorporate energy loss from the shock due to expansion of shocked material in calculating porous Hugoniot. Results obtained for Cu, even up to initial porosities ten, show good agreement with experimental data.

  9. Titration calorimetry of anesthetic-protein interaction: negative enthalpy of binding and anesthetic potency.

    PubMed

    Ueda, I; Yamanaka, M

    1997-04-01

    Anesthetic potency increases at lower temperatures. In contrast, the transfer enthalpy of volatile anesthetics from water to macromolecules is usually positive. The transfer decreases at lower temperature. It was proposed that a few selective proteins bind volatile anesthetics with negative delta H, and these proteins are involved in signal transduction. There has been no report on direct estimation of binding delta H of anesthetics to proteins. This study used isothermal titration calorimetry to analyze chloroform binding to bovine serum albumin. The calorimetrically measured delta H cal was -10.37 kJ.mol-1. Thus the negative delta H of anesthetic binding is not limited to signal transduction proteins. The binding was saturable following Fermi-Dirac statistics and is characterized by the Langmuir adsorption isotherms, which is interfacial. The high-affinity association constant, K, was 2150 +/- 132 M-1 (KD = 0.47 mM) with the maximum binding number, Bmax = 3.7 +/- 0.2. The low-affinity K was 189 +/- 3.8 M-1 (KD = 5.29 mM), with a Bmax of 13.2 +/- 0.3. Anesthetic potency is a function of the activity of anesthetic molecules, not the concentration. Because the sign of delta H determines the temperature dependence of distribution of anesthetic molecules, it is irrelevant to the temperature dependence of anesthetic potency.

  10. Major and trace element composition of copiapite-group minerals and coexisting water from the Richmond mine, Iron Mountain, California

    USGS Publications Warehouse

    Jamieson, H.E.; Robinson, C.; Alpers, Charles N.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Peterson, Ronald C.

    2005-01-01

    Copiapite-group minerals of the general formula AR4 (SO4)6(OH)2??nH2O, where A is predominantly Mg, Fe2+, or 0.67Al3+, R is predominantly Fe3+, and n is typically 20, are among several secondary hydrous Fe sulfates occurring in the inactive mine workings of the massive sulfide deposit at Iron Mountain, CA, a USEPA Superfund site that produces extremely acidic drainage. Samples of copiapite-group minerals, some with coexisting water, were collected from the Richmond mine. Approximately 200 mL of brownish pore water with a pH of -0.9 were extracted through centrifugation from a 10-L sample of moist copiapite-group minerals taken from pyritic muck piles. The pore water is extremely rich in ferric iron (Fe3+=149 g L-1, FeT=162 g L-1 and has a density of 1.52 g mL-1. The composition of the pore water is interpreted in the context of published phase relations in the Fe2O3- SO3-H2O system and previous work on the chemistry of extremely acid mine waters and associated minerals in the Richmond mine. Two distinct members of the copiapite mineral group were identified in the samples with coexisting water: (1) abundant magnesiocopiapite consisting of platy crystals 10 to 50 ??m and (2) minor aluminocopiapite present as smaller platy crystals that form spheroidal aggregates. The average composition (n=5) of the magnesiocopiapite is (Mg0.90Fe0.172+ Zn0.02Cu0.01)???1.10(Fe3.833+Al0.09)???3.92(SO4) 6.00(OH)1.96??20H2O. Bulk compositions determined by digestion and wet-chemical analysis are consistent with the microanalytical results. These results suggest that magnesiocopiapite is the least soluble member of the copiapite group under the prevailing conditions. Micro-PIXE analysis indicates that the copiapite-group minerals in this sample sequester Zn (average 1420 ppm), with lesser amounts of Cu (average 270 ppm) and As (average 64 ppm). ?? 2004 Elsevier B.V. All rights reserved.

  11. [The prospects for using potable mineral waters as agents for the primary prevention of gastroduodenal ulcers].

    PubMed

    Polushina, N D; Frolkov, V K

    1990-01-01

    Primary preventive effects of mineral water Essentuki 17 were investigated on 500 male Wistar rats (body mass 200-250 g). It is demonstrated that oral pretreatment with the above water can prevent the onset of gastroduodenal ulcers. Changes in secretion of gastrin, insulin, glucagon, triiodothyronine and thyroxin support the clinical evidence.

  12. [The risk factor for low bone mineral density in patients with inflammatory bowel disease].

    PubMed

    Liu, Jian-bin; Gao, Xiang; Zhang, Fang-bin; Yang, Li; Xiao, Ying-lian; Zhang, Rui-dong; Li, Zi-ping; Hu, Pin-jin; Chen, Min-hu

    2009-10-01

    To evaluate the prevalence of low bone mineral density in patients with inflammatory bowel disease (IBD)and to identify its risk factors. A cross-sectional survey was carried out in IBD patients. Anthropometric measures, biochemical markers of nutrition and bone mineral density measurement were completed for these patients as well as healthy control subjects. Seventy-seven Crohn's disease (CD) and 43 ulcerative colitis (UC) patients were enrolled, and 37 healthy volunteers were recruited as healthy controls (HC). The T value of CD patients, UC patients and HC was -1.72 +/- 1.20, -1.26 +/- 1.12 and -0.62 +/- 0.87 respectively and the T value of CD patients was significantly lower than that of HC (P = 0.000). The prevalence of osteoporosis in CD, UC and HC was 23.3%, 14.0% and 0 respectively. The prevalence of osteoporosis in CD was higher than that in HC (P = 0.003). Logistic regression analysis indicated that low BMI (BMI < or = 18.4 kg/m(2)) was an independent risk factor for osteoporosis both in CD (OR = 11.25, 95%CI 3.198 - 39.580, P = 0.000) and in UC (OR = 14.50, 95%CI 1.058 - 88.200, P = 0.045) patients. Age, disease duration, clinical activity active index (CDAI), oral steroid therapy, immunosuppressant treatment and serum vitamin D concentration were not found to be correlated with osteoporosis in IBD patients. Low bone mineral density is common in both CD and UC patients and low BMI is an independent risk factor for osteoporosis in IBD patients.

  13. Mineralization of a Malaysian crude oil by Pseudomonas sp. and Achromabacter sp. isolated from coastal waters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ahmad, J.; Ahmad, M.F.

    1995-12-31

    Regarded as being a potentially effective tool to combat oil pollution, bioremediation involves mineralization, i.e., the conversion of complex hydrocarbons into harmless CO{sub 2} and water by action of microorganisms. Therefore, in achieving optimum effectiveness from the application of these products on crude oil in local environments, the capability of the bacteria to mineralize hydrocarbons was evaluated. The microbial laboratory testing of mineralization on local oil degraders involved, first, isolation of bacteria found at a port located on the west coast of Peninsular Malaysia. Subsequently, these bacteria were identified by means of Biomereux`s API 20E and 20 NE systems andmore » later screened by their growth on a Malaysian crude oil. Selected strains of Pseudomonas sp. and Achromabacter sp. were then exposed individually to a similar crude oil in a mineralization unit and monitored for 16 days for release of CO{sub 2}. Pseudomonas paucimobilis was found to produce more CO{sub 2} than Achromobacter sp. When tested under similar conditions, mixed populations of these two taxa produced more CO{sub 2} than that produced by any individual strain. Effective bioremediation of local crude in Malaysian waters can therefore be achieved from biochemically developed Pseudomonas sp. strains.« less

  14. Determination of some pure compound ideal-gas enthalpies of formation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Steele, W. V.; Chirico, R. D.; Nguyen, A.

    1989-06-01

    The results of a study aimed at improvement of group-additivity methodology for estimation of thermodynamic properties of organic substances are reported. Specific weaknesses where ring corrections were unknown or next-nearest-neighbor interactions were only estimated because of lack of experimental data are addressed by experimental studies of enthalpies of combustion in the condensed- phase and vapor pressure measurements. Ideal-gas enthalpies of formation are reported for acrylamide, succinimide, ..gamma..-butyrolactone, 2-pyrrolidone, 2,3-dihydrofuran, 3,4-dihydro-2H-pyran, 1,3-cyclohexadiene, 1,4-cyclohexadiene, and 1-methyl-1-phenylhydrazine. Ring corrections, group terms, and next-nearest-neighbor interaction terms useful in the application of group additivity correlations are derived. 44 refs., 2 figs., 59 tabs.

  15. Estimating the melting point, entropy of fusion, and enthalpy of fusion of organic compounds via SPARC.

    PubMed

    Whiteside, T S; Hilal, S H; Brenner, A; Carreira, L A

    2016-08-01

    The entropy of fusion, enthalpy of fusion, and melting point of organic compounds can be estimated through three models developed using the SPARC (SPARC Performs Automated Reasoning in Chemistry) platform. The entropy of fusion is modelled through a combination of interaction terms and physical descriptors. The enthalpy of fusion is modelled as a function of the entropy of fusion, boiling point, and flexibility of the molecule. The melting point model is the enthalpy of fusion divided by the entropy of fusion. These models were developed in part to improve SPARC's vapour pressure and solubility models. These models have been tested on 904 unique compounds. The entropy model has a RMS of 12.5 J mol(-1) K(-1). The enthalpy model has a RMS of 4.87 kJ mol(-1). The melting point model has a RMS of 54.4°C.

  16. The Impact of Organo-Mineral Complexation on Mineral Weathering in the Soil Zone under Unsaturated Conditions

    NASA Astrophysics Data System (ADS)

    Michael, H. A.; Tan, F.; Yoo, K.; Imhoff, P. T.

    2017-12-01

    While organo-mineral complexes can protect organic matter (OM) from biodegradation, their impact on soil mineral weathering is not clear. Previous bench-scale experiments that focused on specific OM and minerals showed that the adsorption of OM to mineral surfaces accelerates the dissolution of some minerals. However, the impact of natural organo-mineral complexes on mineral dissolution under unsaturated conditions is not well known. In this study, soil samples prepared from an undisturbed forest site were used to determine mineral weathering rates under differing conditions of OM sorption to minerals. Two types of soil samples were generated: 1) soil with OM (C horizon soil from 84-100cm depth), and 2) soil without OM (the same soil as in 1) but with OM removed by heating to 350°for 24 h). Soil samples were column-packed and subjected to intermittent infiltration and drainage to mimic natural rainfall events. Each soil sample type was run in duplicate. The unsaturated condition was created by applying gas pressure to the column, and the unsaturated chemical weathering rates during each cycle were calculated from the effluent concentrations. During a single cycle, when applying the same gas pressure, soils with OM retained more moisture than OM-removed media, indicating increased water retention capacity under the impact of OM. This is consistent with the water retention data measured by evaporation experiments (HYPROP) and the dew point method (WP4C Potential Meter). Correspondingly, silicon (Si) denudation rates indicated that dissolution of silicate minerals was 2-4 times higher in OM soils, suggesting that organo-mineral complexes accelerate mineral dissolution under unsaturated conditions. When combining data from all cycles, the results showed that Si denudation rates were positively related to soil water content: denundation rate increased with increasing water content. Therefore, natural mineral chemical weathering under unsaturated conditions, while

  17. Effects of Different Mineral Admixtures on the Properties of Fresh Concrete

    PubMed Central

    Nuruddin, Muhammad Fadhil; Shafiq, Nasir

    2014-01-01

    This paper presents a review of the properties of fresh concrete including workability, heat of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA). Comparison of normal and high-strength concrete in which cement has been partially supplemented by mineral admixture has been considered. It has been concluded that mineral admixtures may be categorized into two groups: chemically active mineral admixtures and microfiller mineral admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete but increase the heat of hydration and reactivity. On the other hand, microfiller mineral admixtures increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In general, small particle size and higher specific surface area of mineral admixture are favourable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water which may be offset by adding effective superplasticizer. PMID:24701196

  18. Effects of different mineral admixtures on the properties of fresh concrete.

    PubMed

    Khan, Sadaqat Ullah; Nuruddin, Muhammad Fadhil; Ayub, Tehmina; Shafiq, Nasir

    2014-01-01

    This paper presents a review of the properties of fresh concrete including workability, heat of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA). Comparison of normal and high-strength concrete in which cement has been partially supplemented by mineral admixture has been considered. It has been concluded that mineral admixtures may be categorized into two groups: chemically active mineral admixtures and microfiller mineral admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete but increase the heat of hydration and reactivity. On the other hand, microfiller mineral admixtures increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In general, small particle size and higher specific surface area of mineral admixture are favourable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water which may be offset by adding effective superplasticizer.

  19. Subsurface water and clay mineral formation during the early history of Mars.

    PubMed

    Ehlmann, Bethany L; Mustard, John F; Murchie, Scott L; Bibring, Jean-Pierre; Meunier, Alain; Fraeman, Abigail A; Langevin, Yves

    2011-11-02

    Clay minerals, recently discovered to be widespread in Mars's Noachian terrains, indicate long-duration interaction between water and rock over 3.7 billion years ago. Analysis of how they formed should indicate what environmental conditions prevailed on early Mars. If clays formed near the surface by weathering, as is common on Earth, their presence would indicate past surface conditions warmer and wetter than at present. However, available data instead indicate substantial Martian clay formation by hydrothermal groundwater circulation and a Noachian rock record dominated by evidence of subsurface waters. Cold, arid conditions with only transient surface water may have characterized Mars's surface for over 4 billion years, since the early-Noachian period, and the longest-duration aqueous, potentially habitable environments may have been in the subsurface.

  20. Lattice model for water-solute mixtures.

    PubMed

    Furlan, A P; Almarza, N G; Barbosa, M C

    2016-10-14

    A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction of solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting in, hydrophilic, inert, and hydrophobic interactions. Extensive Monte Carlo simulations were carried out, and the behavior of pure components and the excess properties of the mixtures have been studied. The pure components, water (solvent) and solute, have quite similar phase diagrams, presenting gas, low density liquid, and high density liquid phases. In the case of solute, the regions of coexistence are substantially reduced when compared with both the water and the standard ALG models. A numerical procedure has been developed in order to attain series of results at constant pressure from simulations of the lattice gas model in the grand canonical ensemble. The excess properties of the mixtures, volume and enthalpy as the function of the solute fraction, have been studied for different interaction parameters of the model. Our model is able to reproduce qualitatively well the excess volume and enthalpy for different aqueous solutions. For the hydrophilic case, we show that the model is able to reproduce the excess volume and enthalpy of mixtures of small alcohols and amines. The inert case reproduces the behavior of large alcohols such as propanol, butanol, and pentanol. For the last case (hydrophobic), the excess properties reproduce the behavior of ionic liquids in aqueous solution.

  1. The effect of pyrite on E. coli in water: Proof-of-concept for the elimination of waterborne bacteria by reactive minerals

    PubMed Central

    Friedlander, Lonia R.; Puri, Neha; Schoonen, Martin A.A.; Karzai, A. Wali

    2015-01-01

    We present proof-of-concept results for the elimination of waterborne bacteria by reactive minerals. We exposed E.coli MG1655 suspended in water to the reactive mineral pyrite (FeS2) at room temperature and ambient light. This slurry eliminates 99.9% of bacteria in fewer than 4 hours. We also exposed E. coli to pyrite leachate (supernatant liquid from slurry after 24-hours), which eliminates 99.99% of bacteria over the same time-scale. Unlike SOlar water DISinfection (SODIS) our results do not depend on the presence of ultraviolet (UV) light. We confirmed this by testing proposed SODIS additive and known photo-catalyst anatase (TiO2) for antibacterial properties and found that, in contrast to pyrite, it does not eliminate E. coli under our experimental conditions. Previous investigations of naturally antibiotic minerals have focused on the medical applications of antibiotic clays, and thus have not been conducted under experimental conditions resembling those found in water purification. In our examination of the relevant literature, we have not found previously reported evidence for the use of reactive minerals in water sanitization. The results from this proof-of-concept experiment may have important implications for future directions in household water purification research. PMID:25719464

  2. Risk Assessment of Mineral Groundwater Near Rogaška Slatina

    NASA Astrophysics Data System (ADS)

    Trcek, Branka; Leis, Albrecht

    2017-10-01

    Groundwater resources of mineral and thermo-mineral water are invaluable for planning a sustainable spatial and economic development of the Rogaška Slatina area, which requires a protection of this natural heritage. Numerous previous investigations of Rogaška groundwaters were subjects to balneology and to demands for larger exploitation quantities, that is why information are missing that are essential for definition of the Rogaška fractured aquifer system with mineral and thermo-mineral water and for its protection. The isotopic investigations of groundwaters stored in the Rogaška Slatina fractured aquifer system were performed aiming at answering open questions on the groundwater recharge and dynamics, on connections between different types of aquifers and on solute transport. Environmental isotopes 2H, 18O, 3H, 13C of dissolved inorganic carbon and 14C were analysed in mineral, thermo-mineral and spring waters. Results indicated the source and mechanism of groundwater recharge, its renewability, a transit time distribution, hydraulic interrelationships, the groundwater origin and its evolution due to effects of water-rock interaction. The mean residence time estimates of mineral and thermo- mineral water in the aquifer are between 3400 and 14000 years. On the other hand, the mixing processes between younger and older waters or mineral and spring waters are reflected as well as waters that infiltrated predominantly after the 1960s. These suggest the vulnerability of the research systems to man-made impacts. The presented results coupled with available information on a physical hydrogeology and water chemistry asses the optimal balance between the environmental protection and economic use of mineral water resources in the study area. They are essential for the protection strategy development of mineral and thermo-mineral water in the Rogaška Slatina area bringing together the state administration and local authorities and stakeholders.

  3. Evidence for low-grade metamorphism, hydrothermal alteration, and diagenesis on Mars from phyllosilicate mineral assemblages

    USGS Publications Warehouse

    Ehlmann, Bethany L.; Mustard, John F; Clark, Roger N.; Swayze, Gregg A.; Murchie, Scott L.

    2011-01-01

    The enhanced spatial and spectral resolution provided by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter (MRO) has led to the discovery of numerous hydrated silicate minerals on Mars, particularly in the ancient, cratered crust comprising the southern highlands. Phases recently identified using visible/near-infrared spectra include: smectite, chlorite, prehnite, high-charge phyllosilicates (illite or muscovite), the zeolite analcime, opaline silica, and serpentine. Some mineral assemblages represent the products of aqueous alteration at elevated temperatures. Geologic occurrences of these mineral assemblages are described using examples from west of the Isidis basin near the Nili Fossae and with reference to differences in implied temperature, fluid composition, and starting materials during alteration. The alteration minerals are not distributed homogeneously. Rather, certain craters host distinctive alteration assemblages: (1) prehnite-chlorite-silica, (2) analcime-silica-Fe,Mg-smectite-chlorite, (3) chlorite-illite (muscovite), and (4) serpentine, which furthermore has been found in bedrock units. These assemblages contrast with the prevalence of solely Fe,Mg-smectites in most phyllosilicate-bearing terrains on Mars, and they represent materials altered at depth then exposed by cratering. Of the minerals found to date, prehnite provides the clearest evidence for subsurface, hydrothermal/metamorphic alteration, as it forms only under highly restricted conditions (T = 200–400ºC). Multiple mechanisms exist for forming the other individual minerals; however, the most likely formation mechanisms for the characteristic mineralogic assemblages observed are, for (1) and (2), low-grade metamorphism or hydrothermal (<400ºC) circulation of fluids in basalt; for (3), transformation of trioctahedral smectites to chlorite and dioctahedral smectites to illite during diagenesis; and for (4), low-grade metamorphism or

  4. Managing the potential risks of using bacteria-laden water in mineral processing to protect freshwater.

    PubMed

    Liu, Wenying; Moran, Chris J; Vink, Sue

    2013-06-18

    The minerals industry is being driven to access multiple water sources and increase water reuse to minimize freshwater withdrawal. Bacteria-laden water, such as treated effluent, has been increasingly used as an alternative to freshwater for mineral processing, in particular flotation, where conditions are favorable for bacterial growth. However, the risk posed by bacteria to flotation efficiency is poorly understood. This could be a barrier to the ongoing use of this water source. This study tested the potential of a previously published risk-based approach as a management tool to both assist mine sites in quantifying the risk from bacteria, and finding system-wide cost-effective solutions for risk mitigation. The result shows that the solution of adjusting the flotation chemical regime could only partly control the risk. The second solution of using tailings as an absorbent was shown to be effective in the laboratory in reducing bacterial concentration and thus removing the threat to flotation recovery. The best solution is likely to combine internal and external approaches, that is, inside and outside processing plants. Findings in this study contribute possible methods applicable to managing the risk from water-borne bacteria to plant operations that choose to use bacteria-containing water, when attempting to minimize freshwater use, and avoiding the undesirable consequences of increasing its use.

  5. Formation of secondary minerals in a lysimeter approach - A mineral-microbe interaction

    NASA Astrophysics Data System (ADS)

    Schäffner, F.; Merten, D.; De Giudici, G.; Beyer, A.; Akob, D. M.; Ricci, P. C.; Küsel, K.; Büchel, G.

    2012-04-01

    Heavy metal contamination of large areas due to uranium mining operations poses a serious long-term environmental problem. In the Ronneburg district (eastern Thuringia, Germany), leaching of low grade uranium bearing ores (uranium content < 300 g/t) occurred from 1972 to 1990 using acid mine drainage (AMD; pH 2.7-2.8) and diluted sulphuric acid (10 g/l). Secondary mineral phases like birnessite, todorokite and goethite occur within a natural attenuation process associated with enrichment of heavy metals, especially Cd, Ni, Co, Cu and Zn due to a residual contamination even after remediation efforts. To reveal the processes of secondary mineral precipitation in the field a laboratory lysimeter approach was set up under in situ-like conditions. Homogenized soil from the field site and pure quartz sand were used as substrates. In general, in situ measurements of redox potentials in the substrates showed highly oxidizing conditions (200-750 mV). Water was supplied to the lysimeter from below via a mariottés bottle containing contaminated groundwater from the field. Evaporation processes were allowed, providing a continuous flow of water. This led to precipitation of epsomite and probably aplowite on the top layer of substrate, similar to what is observed in field investigations. After 4 weeks, the first iron and manganese bearing secondary minerals became visible. Soil water samples were used to monitor the behaviour of metals within the lysimeter. Saturation indices (SI) for different secondary minerals were calculated with PHREEQC. The SI of goethite showed oversaturation with respect to the soil solution. SEM-EDX analyses and IR spectroscopy confirmed the formation of goethite. Geochemical data revealed that goethite formation was mainly dominated by Eh/pH processes and that heavy metals, e.g. Zn and U, could be enriched in this phase. Although Eh/pH data does not support formation of manganese minerals, Mn(II)-oxidizing bacteria (MOB) could be isolated from field

  6. Microcalorimetric and potentiometric titration studies on the adsorption of copper by extracellular polymeric substances (EPS), minerals and their composites.

    PubMed

    Fang, Linchuan; Huang, Qiaoyun; Wei, Xing; Liang, Wei; Rong, Xinming; Chen, Wenli; Cai, Peng

    2010-08-01

    Equilibrium adsorption experiments, isothermal titration calorimetry and potentiometric titration techniques were employed to investigate the adsorption of Cu(II) by extracellular polymeric substances (EPS) extracted from Pseudomonas putida X4, minerals (montmorillonite and goethite) and their composites. Compared with predicted values of Cu(II) adsorption on composites, the measured values of Cu(II) on EPS-montmorillonite composite increased, however, those on EPS-goethite composite decreased. Potentiometric titration results also showed that more surface sites were observed on EPS-montmorillonite composite and less reactive sites were found on EPS-goethite composite. The adsorption of Cu(II) on EPS molecules and their composites with minerals was an endothermic reaction, while that on minerals was exothermic. The positive values of enthalpy change (Delta H) and entropy change (DeltaS) for Cu(II) adsorption on EPS and mineral-EPS composites indicated that Cu(II) mainly interacts with carboxyl and phosphoryl groups as inner-sphere complexes on EPS molecules and their composites with minerals. (c) 2010 Elsevier Ltd. All rights reserved.

  7. [Mechanism of tritium persistence in porous media like clay minerals].

    PubMed

    Wu, Dong-Jie; Wang, Jin-Sheng; Teng, Yan-Guo; Zhang, Ke-Ni

    2011-03-01

    To investigate the mechanisms of tritium persistence in clay minerals, three types of clay soils (montmorillonite, kaolinite and illite) and tritiated water were used in this study to conduct the tritium sorption tests and the other related tests. Firstly, the ingredients, metal elements and heat properties of clay minerals were studied with some instrumental analysis methods, such as ICP and TG. Secondly, with a specially designed fractionation and condensation experiment, the adsorbed water, the interlayer water and the structural water in the clay minerals separated from the tritium sorption tests were fractionated for investigating the tritium distributions in the different types of adsorptive waters. Thirdly, the location and configuration of tritium adsorbed into the structure of clay minerals were studied with infrared spectrometry (IR) tests. And finally, the forces and mechanisms for driving tritium into the clay minerals were analyzed on the basis of the isotope effect of tritium and the above tests. Following conclusions have been reached: (1) The main reason for tritium persistence in clay minerals is the entrance of tritium into the adsorbed water, the interlayer water and the structural water in clay minerals. The percentage of tritium distributed in these three types of adsorptive water are in the range of 13.65% - 38.71%, 0.32% - 5.96%, 1.28% - 4.37% of the total tritium used in the corresponding test, respectively. The percentages are different for different types of clay minerals. (2) Tritium adsorbed onto clay minerals are existed in the forms of the tritiated hydroxyl radical (OT) and the tritiated water molecule (HTO). Tritium mainly exists in tritiated water molecule for adsorbed water and interlayer water, and in tritiated hydroxyl radical for structural water. (3) The forces and effects driving tritium into the clay minerals may include molecular dispersion, electric charge sorption, isotope exchange and tritium isotope effect.

  8. Stable isotope, chemical, and mineral compositions of the Middle Proterozoic Lijiaying Mn deposit, Shaanxi Province, China

    USGS Publications Warehouse

    Yeh, Hsueh-Wen; Hein, James R.; Ye, Jie; Fan, Delian

    1999-01-01

    The Lijiaying Mn deposit, located about 250 km southwest of Xian, is a high-quality ore characterized by low P and Fe contents and a mean Mn content of about 23%. The ore deposit occurs in shallow-water marine sedimentary rocks of probable Middle Proterozoic age. Carbonate minerals in the ore deposit include kutnahorite, calcite, Mn calcite, and Mg calcite. Carbon (−0.4 to −4.0‰) and oxygen (−3.7 to −12.9‰) isotopes show that, with a few exceptions, those carbonate minerals are not pristine low-temperature marine precipitates. All samples are depleted in rare earth elements (REEs) relative to shale and have negative Eu and positive Ce anomalies on chondrite-normalized plots. The Fe/Mn ratios of representative ore samples range from about 0.034 to <0.008 and P/Mn from 0.0023 to <0.001. Based on mineralogical data, the low ends of those ranges of ratios are probably close to ratios for the pure Mn minerals. Manganese contents have a strong positive correlation with Ce anomaly values and a moderate correlation with total REE contents. Compositional data indicate that kutnahorite is a metamorphic mineral and that most calcites formed as low-temperature marine carbonates that were subsequently metamorphosed. The braunite ore precursor mineral was probably a Mn oxyhydroxide, similar to those that formed on the deep ocean-floor during the Cenozoic. Because the Lijiaying precursor mineral formed in a shallow-water marine environment, the atmospheric oxygen content during the Middle Proterozoic may have been lower than it has been during the Cenozoic.

  9. Generation of Hydrogen and Methane during Experimental Low-Temperature Reaction of Ultramafic Rocks with Water

    NASA Astrophysics Data System (ADS)

    McCollom, Thomas M.; Donaldson, Christopher

    2016-06-01

    Serpentinization of ultramafic rocks is widely recognized as a source of molecular hydrogen (H2) and methane (CH4) to support microbial activity, but the extent and rates of formation of these compounds in low-temperature, near-surface environments are poorly understood. Laboratory experiments were conducted to examine the production of H2 and CH4 during low-temperature reaction of water with ultramafic rocks and minerals. Experiments were performed by heating olivine or harzburgite with aqueous solutions at 90°C for up to 213 days in glass bottles sealed with butyl rubber stoppers. Although H2 and CH4 increased steadily throughout the experiments, the levels were very similar to those found in mineral-free controls, indicating that the rubber stoppers were the predominant source of these compounds. Levels of H2 above background were observed only during the first few days of reaction of harzburgite when CO2 was added to the headspace, with no detectable production of H2 or CH4 above background during further heating of the harzburgite or in experiments with other mineral reactants. Consequently, our results indicate that production of H2 and CH4 during low-temperature alteration of ultramafic rocks may be much more limited than some recent experimental studies have suggested. We also found no evidence to support a recent report suggesting that spinels in ultramafic rocks may stimulate H2 production. While secondary silicates were observed to precipitate during the experiments, formation of these deposits was dominated by Si released by dissolution of the glass bottles, and reaction of the primary silicate minerals appeared to be very limited. While use of glass bottles and rubber stoppers has become commonplace in experiments intended to study processes that occur during serpentinization of ultramafic rocks at low temperatures, the high levels of H2, CH4, and SiO2 released during heating indicate that these reactor materials are unsuitable for this purpose.

  10. Generation of Hydrogen and Methane during Experimental Low-Temperature Reaction of Ultramafic Rocks with Water.

    PubMed

    McCollom, Thomas M; Donaldson, Christopher

    2016-06-01

    Serpentinization of ultramafic rocks is widely recognized as a source of molecular hydrogen (H2) and methane (CH4) to support microbial activity, but the extent and rates of formation of these compounds in low-temperature, near-surface environments are poorly understood. Laboratory experiments were conducted to examine the production of H2 and CH4 during low-temperature reaction of water with ultramafic rocks and minerals. Experiments were performed by heating olivine or harzburgite with aqueous solutions at 90°C for up to 213 days in glass bottles sealed with butyl rubber stoppers. Although H2 and CH4 increased steadily throughout the experiments, the levels were very similar to those found in mineral-free controls, indicating that the rubber stoppers were the predominant source of these compounds. Levels of H2 above background were observed only during the first few days of reaction of harzburgite when CO2 was added to the headspace, with no detectable production of H2 or CH4 above background during further heating of the harzburgite or in experiments with other mineral reactants. Consequently, our results indicate that production of H2 and CH4 during low-temperature alteration of ultramafic rocks may be much more limited than some recent experimental studies have suggested. We also found no evidence to support a recent report suggesting that spinels in ultramafic rocks may stimulate H2 production. While secondary silicates were observed to precipitate during the experiments, formation of these deposits was dominated by Si released by dissolution of the glass bottles, and reaction of the primary silicate minerals appeared to be very limited. While use of glass bottles and rubber stoppers has become commonplace in experiments intended to study processes that occur during serpentinization of ultramafic rocks at low temperatures, the high levels of H2, CH4, and SiO2 released during heating indicate that these reactor materials are unsuitable for this purpose

  11. Interactions of 14C-labeled multi-walled carbon nanotubes with soil minerals in water.

    PubMed

    Zhang, Liwen; Petersen, Elijah J; Zhang, Wen; Chen, Yongsheng; Cabrera, Miguel; Huang, Qingguo

    2012-07-01

    Carbon nanotubes are often modified to be stable in the aqueous phase by adding extensive hydrophilic surface functional groups. The stability of such CNTs in water with soil or sediment is one critical factor controlling their environmental fate. We conducted a series of experiments to quantitatively assess the association between water dispersed multi-walled carbon nanotubes (MWCNTs) and three soil minerals (kaolinite, smectite, or shale) in aqueous solution under different sodium concentrations. (14)C-labeling was used in these experiments to unambiguously quantify MWCNTs. The results showed that increasing ionic strength strongly promoted the removal of MWCNTs from aqueous phase. The removal tendency is inversely correlated with the soil minerals' surface potential and directly correlated with their hydrophobicity. This removal can be interpreted by the extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory especially for kaolinite and smectite. Shale, which contains large and insoluble organic materials, sorbed MWCNTs the most strongly. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Core level electron energy-loss spectra of minerals: pre-edge fine structures at the oxygen K-edge . Comment on ``Water in minerals detectable by electron energy-loss spectroscopy EELS'' by R. Wirth, Phys Chem Minerals (1997) 24:561-568

    NASA Astrophysics Data System (ADS)

    van Aken, P. A.; Liebscher, B.; Styrsa, V. J.

    In a recent paper entitled ``Water in minerals detectable by electron energy-loss spectroscopy EELS'' by R. Wirth, it has been claimed that OH-- and H2O-bearing minerals exhibit a characteristic peak in the ELNES spectra at about 528 eV prior to the onset of the O K-edge at 532 eV, which could be used for (semi-)quantitative determination of water- or OH-contents on a nanometer scale. It is shown here by parallel electron energy-loss spectroscopy (PEELS) recorded in a transmission electron microscope (TEM) that O K-pre-edge peaks with very high intensities may also exist in water-free compounds and minerals, in particular when they contain transition metals. These spectral features arise from covalent mixing of the metal and oxygen states, which introduces oxygen p character in unoccupied states of mainly metal character. The point is illustrated by the comparison of hematite (α-Fe2O3) and lepidocrocite (γ-FeOOH) O K-edge PEELS spectra which exhibit similar intensities of the pre-edge peak, despite of their grossly different OH- contents. As a consequence, the general validity of the method proposed by Wirth is questioned.

  13. Electrospinning of calcium phosphate-poly (d,l-lactic acid) nanofibers for sustained release of water-soluble drug and fast mineralization

    PubMed Central

    Fu, Qi-Wei; Zi, Yun-Peng; Xu, Wei; Zhou, Rong; Cai, Zhu-Yun; Zheng, Wei-Jie; Chen, Feng; Qian, Qi-Rong

    2016-01-01

    Calcium phosphate-based biomaterials have been well studied in biomedical fields due to their outstanding chemical and biological properties which are similar to the inorganic constituents in bone tissue. In this study, amorphous calcium phosphate (ACP) nanoparticles were prepared by a precipitation method, and used for preparation of ACP-poly(d,l-lactic acid) (ACP-PLA) nanofibers and water-soluble drug-containing ACP-PLA nanofibers by electrospinning. Promoting the encapsulation efficiency of water-soluble drugs in electrospun hydrophobic polymer nanofibers is a common problem due to the incompatibility between the water-soluble drug molecules and hydrophobic polymers solution. Herein, we used a native biomolecule of lecithin as a biocompatible surfactant to overcome this problem, and successfully prepared water-soluble drug-containing ACP-PLA nanofibers. The lecithin and ACP nanoparticles played important roles in stabilizing water-soluble drug in the electrospinning composite solution. The electrospun drug-containing ACP-PLA nanofibers exhibited fast mineralization in simulated body fluid. The ACP nanoparticles played the key role of seeds in the process of mineralization. Furthermore, the drug-containing ACP-PLA nanofibers exhibited sustained drug release which simultaneously occurred with the in situ mineralization in simulated body fluid. The osteoblast-like (MG63) cells with spreading filopodia were well observed on the as-prepared nanofibrous mats after culturing for 24 hours, indicating a high cytocompatibility. Due to the high biocompatibility, sustained drug release, and fast mineralization, the as-prepared composite nanofibers may have potential applications in water-soluble drug loading and release for tissue engineering. PMID:27785016

  14. Enthalpy By Energy Balance for Aerodynamic Heating Facility at NASA Ames Research Center Arc Jet Complex

    NASA Technical Reports Server (NTRS)

    Hightower, T. Mark; MacDonald, Christine L.; Martinez, Edward R.; Balboni, John A.; Anderson, Karl F.; Arnold, Jim O. (Technical Monitor)

    2002-01-01

    The NASA Ames Research Center (ARC) Arc Jet Facilities' Aerodynamic Heating Facility (AHF) has been instrumented for the Enthalpy By Energy Balance (EB2) method. Diagnostic EB2 data is routinely taken for all AHF runs. This paper provides an overview of the EB2 method implemented in the AHF. The chief advantage of the AHF implementation over earlier versions is the non-intrusiveness of the instruments used. For example, to measure the change in cooling water temperature, thin film 1000 ohm Resistance Temperature Detectors (RTDs) are used with an Anderson Current Loop (ACL) as the signal conditioner. The ACL with 1000 ohm RTDs allows for very sensitive measurement of the increase in temperature (Delta T) of the cooling water to the arc heater, which is a critical element of the EB2 method. Cooling water flow rates are measured with non-intrusive ultrasonic flow meters.

  15. Enthalpy - Improved Dielectric Insulation for Superconducting Wires.

    DTIC Science & Technology

    1982-05-01

    these materials are also bein, studickd as regenerator matrix materials for Stirling cycle cryocoolers (7), yet, 1’~l incredibly enough, their...1A0.Az 4. TI T LE (iind SThti tfe) 5 TYPE OF REPORT & PERIOD COVERFID Enthalpy - Improved Dielectric Insulation for Final JUN 80 - MAR 82...resistance, and suggestions are made for improving these conductivities. The SC-2 and SC-3 type materials have near-metallic thermal conductivities near

  16. Silicate and carbonate mineral weathering in soil profiles developed on Pleistocene glacial drift (Michigan, USA): Mass balances based on soil water geochemistry

    NASA Astrophysics Data System (ADS)

    Jin, Lixin; Williams, Erika L.; Szramek, Kathryn J.; Walter, Lynn M.; Hamilton, Stephen K.

    2008-02-01

    Geochemistry of soil, soil water, and soil gas was characterized in representative soil profiles of three Michigan watersheds. Because of differences in source regions, parent materials in the Upper Peninsula of Michigan (the Tahquamenon watershed) contain only silicates, while those in the Lower Peninsula (the Cheboygan and the Huron watersheds) have significant mixtures of silicate and carbonate minerals. These differences in soil mineralogy and climate conditions permit us to examine controls on carbonate and silicate mineral weathering rates and to better define the importance of silicate versus carbonate dissolution in the early stage of soil-water cation acquisition. Soil waters of the Tahquamenon watershed are the most dilute; solutes reflect amphibole and plagioclase dissolution along with significant contributions from atmospheric precipitation sources. Soil waters in the Cheboygan and the Huron watersheds begin their evolution as relatively dilute solutions dominated by silicate weathering in shallow carbonate-free soil horizons. Here, silicate dissolution is rapid and reaction rates dominantly are controlled by mineral abundances. In the deeper soil horizons, silicate dissolution slows down and soil-water chemistry is dominated by calcite and dolomite weathering, where solutions reach equilibrium with carbonate minerals within the soil profile. Thus, carbonate weathering intensities are dominantly controlled by annual precipitation, temperature and soil pCO 2. Results of a conceptual model support these field observations, implying that dolomite and calcite are dissolving at a similar rate, and further dissolution of more soluble dolomite after calcite equilibrium produces higher dissolved inorganic carbon concentrations and a Mg 2+/Ca 2+ ratio of 0.4. Mass balance calculations show that overall, silicate minerals and atmospheric inputs generally contribute <10% of Ca 2+ and Mg 2+ in natural waters. Dolomite dissolution appears to be a major process

  17. Measurement of the aerothermodynamic state in a high enthalpy plasma wind-tunnel flow

    NASA Astrophysics Data System (ADS)

    Hermann, Tobias; Löhle, Stefan; Zander, Fabian; Fasoulas, Stefanos

    2017-11-01

    This paper presents spatially resolved measurements of absolute particle densities of N2, N2+, N, O, N+ , O+ , e- and excitation temperatures of electronic, rotational and vibrational modes of an air plasma free stream. All results are based on optical emission spectroscopy data. The measured parameters are combined to determine the local mass-specific enthalpy of the free stream. The analysis of the radiative transport, relative and absolute intensities, and spectral shape is used to determine various thermochemical parameters. The model uncertainty of each analysis method is assessed. The plasma flow is shown to be close to equilibrium. The strongest deviations from equilibrium occur for N, N+ and N2+ number densities in the free stream. Additional measurements of the local mass-specific enthalpy are conducted using a mass injection probe as well as a heat flux and total pressure probe. The agreement between all methods of enthalpy determination is good.

  18. Rapid and highly sensitive determination of low-molecular-weight carbonyl compounds in drinking water and natural water by preconcentration HPLC with 2,4-dinitrophenylhydrazine.

    PubMed

    Takeda, Kazuhiko; Katoh, Shinya; Nakatani, Nobutake; Sakugawa, Hiroshi

    2006-12-01

    The aim of this research was to develop a simple procedure for a highly sensitive determination of low-molecular-weight (LMW) carbonyl compounds in drinking water and natural water. We employed a preconcentration HPLC system with 2,4-dinitrophenylhydrazine (DNPH) for the determination of LMW carbonyl compounds. A C-18 reverse-phase preconcentration column was used instead of a sample loop at the sample injection valve. A 0.1 - 5.0 mL portion of the derivatized sample solution was injected with a gas-tight syringe, and a 15% acetonitrile aqueous solution was pushed through the preconcentration column to remove the unreacted excess DNPH, which caused serious interference in the determination of formaldehyde. The detection limits were 1 - 3 nM with a relative standard deviation of 2 - 5% for 20 nM standard solutions (n = 5). The calibration curves were essentially unaffected by coexisting sea salts. Applications to commercial mineral water, tap water, river water, pond water and seawater are presented.

  19. Characterization of biofilm formation in natural water subjected to low-frequency electromagnetic fields.

    PubMed

    Mercier, Anne; Bertaux, Joanne; Lesobre, Jérôme; Gravouil, Kevin; Verdon, Julien; Imbert, Christine; Valette, Eric; Héchard, Yann

    2016-01-01

    Electromagnetic field (EMF) treatment has proven to be effective against mineral scaling in water systems. Therefore, it should be assessed for the treatment of other deposits such as biofilms. In this study, a commercial device producing low-frequency EMF (1-10 kHz) was applied to a reactor fed with natural water for 45 days. The treatment promoted the concentration of microorganisms in suspension and limited the amount of sessile microorganisms in the biofilm, as determined by the measurement of total DNA, qPCR and microscopy. The structure of the bacterial community was assessed by t-RFLP and pyrosequencing analysis. The results showed that EMF treatment affected both planktonic and sessile community composition. EMFs were responsible for a shift in classes of Proteobacteria during development of the biofilm. It may be speculated that the EMF treatment affected particle solubility and/or microorganism hydration. This study indicated that EMFs modulated biofilm formation in natural water.

  20. Change of urinary fluoride and bone metabolism indicators in the endemic fluorosis areas of southern china after supplying low fluoride public water

    PubMed Central

    2013-01-01

    Background Few studies have evaluated health impacts, especially biomarker changes, following implementation of a new environmental policy. This study examined changes in water fluoride, urinary fluoride (UF), and bone metabolism indicators in children after supplying low fluoride public water in endemic fluorosis areas of Southern China. We also assessed the relationship between UF and serum osteocalcin (BGP), calcitonin (CT), alkaline phosphatase (ALP), and bone mineral density to identify the most sensitive bone metabolism indicators related to fluoride exposure. Methods Four fluorosis-endemic villages (intervention villages) in Guangdong, China were randomly selected to receive low-fluoride water. One non-endemic fluorosis village with similar socio-economic status, living conditions, and health care access, was selected as the control group. 120 children aged 6-12 years old were randomly chosen from local schools in each village for the study. Water and urinary fluoride content as well as serum BGP, CT, ALP and bone mineral density were measured by the standard methods and compared between the children residing in the intervention villages and the control village. Benchmark dose (BMD) and benchmark dose lower limit (BMDL) were calculated for each bone damage indicator. Results Our study found that after water source change, fluoride concentrations in drinking water in all intervention villages (A-D) were significantly reduced to 0.11 mg/l, similar to that in the control village (E). Except for Village A where water change has only been taken place for 6 years, urinary fluoride concentrations in children of the intervention villages were lower or comparable to those in the control village after 10 years of supplying new public water. The values of almost all bone indicators in children living in Villages B-D and ALP in Village A were either lower or similar to those in the control village after the intervention. CT and BGP are sensitive bone metabolism

  1. [The burden of disease attributed to low bone mineral density among population aged ≥40 years old in China, 1990 and 2013].

    PubMed

    Zhao, Z P; Ai, H H; Li, Y C; Wang, L M; Yin, P; Zhang, M; Deng, Q; Huang, Z J; Liu, J M; Liu, Y N; Gao, Y J; Zhou, M G

    2016-09-06

    Objective: To identify cause-specific death and attributed burden of low bone mineral density in China among population aged ≥40 years old , 1990 and 2013. Methods: By using data from Global Burden of Disease(GBD)2013, this study analyzed death caused by low mineral density, and disability-adjusted life years(DALY)among population aged 40 and above in China(not including Taiwan, China). This study also analyzed DALY by composition of injury which due to low bone mineral density. It also analyzed changes in DALY by provinces in China, 1990 and 2013. An average world population age-structure for the period 2000- 2025 was adopted to calculate the age standardized rates. Results: In 2013, there were 38.1 thousands male and 30.7 thousands female who aged 40 and above dead due to low bone mineral density in China. The burden of injury caused by low bone mineral density was more sever in male than female, which accounted for 1.525 million DALY in male and 0.873 million DALY in female. In 1990, low bone mineral density attributed transportation and accidental injury caused 0.794 million and 0.567 million DALY losses, respectively. In 2013, low bone mineral density attributed transportation and accidental injury caused 1.421 million and 0.951 million DALY losses, respectively. Compared to 1990, DALY losses caused by transportation and accidental injury, increased by 79.1% and 67.6%, respectively. In 1990, DALY rate losses due to low bone mineral density attributed transportation and accidental injury were 68.1 per 100 000 and 48.7 per 100 000, respectively. In 2013, DALY rate losses due to low bone mineral density attributed transportation and accidental injury were 102.0 per 100 000 and 68.2 per 100 000, respectively. Compared to 1990, DALY rates which caused by transportation and accidental injury, increased by 49.8% and 40.2%, respectively. According to the ranking of standardized DALY rate in 2013 by provinces, the top 3 provinces, which standardized DALYs attributed

  2. Trace element abundances in major minerals of Late Permian coals from southwestern Guizhou province, China

    USGS Publications Warehouse

    Zhang, Jiahua; Ren, D.; Zheng, C.; Zeng, R.; Chou, C.-L.; Liu, J.

    2002-01-01

    Fourteen samples of minerals were separated by handpicking from Late Permian coals in southwestern Guizhou province, China. These 14 minerals were nodular pyrite, massive recrystallized pyrite, pyrite deposited from low-temperature hydrothermal fluid and from ground water; clay minerals; and calcite deposited from low-temperature hydrothermal fluid and from ground water. The mineralogy, elemental composition, and distribution of 33 elements in these samples were studied by optical microscopy, scanning electron microscope equipped with energy-dispersive X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), cold-vapor atomic absorption spectrometry (CV-AAS), atomic fluorescence spectrometry (AFS), inductively coupled-plasma mass spectrometry (ICP-MS), and ion-selective electrode (ISE). The results show that various minerals in coal contain variable amounts of trace elements. Clay minerals have high concentrations of Ba, Be, Cs, F, Ga, Nb, Rb, Th, U, and Zr. Quartz has little contribution to the concentration of trace elements in bulk coal. Arsenic, Mn, and Sr are in high concentrations in calcite. Pyrite has high concentrations of As, Cd, Hg, Mo, Sb, Se, Tl, and Zn. Different genetic types of calcite in coal can accumulate different trace elements; for example Ba, Co, Cr, Hg, Ni, Rb, Sn, Sr, and Zn are in higher concentrations in calcite deposited from low-temperature hydrothermal fluid than in that deposited from ground water. Furthermore, the concentrations of some trace elements are quite variable in pyrite; different genetic types of pyrites (Py-A, B, C, D) have different concentrations of trace elements, and the concentrations of trace elements are also different in pyrite of low-temperature hydrothermal origin collected from different locations. The study shows that elemental concentration is rather uniform in a pyrite vein. There are many micron and submicron mosaic pyrites in a pyrite vein, which is enriched in some trace elements, such as As and Mo. The

  3. Isothermogravimetric determination of the enthalpies of vaporization of 1-alkyl-3-methylimidazolium ionic liquids.

    PubMed

    Luo, Huimin; Baker, Gary A; Dai, Sheng

    2008-08-21

    Vaporization enthalpies for two series of ionic liquids (ILs) composed of 1- n-alkyl-3-methylimidazolium cations, [Imm1+] (m=2, 3, 4, 6, 8, or 10), paired with either the bis(trifluoromethanesulfonyl)amide, [Tf2N-], or the bis(perfluoroethylsulfonyl)amide anion, [beti-], were determined using a simple, convenient, and highly reproducible thermogravimetric approach, and from these values, Hildebrand solubility parameters were estimated. Our results reveal two interesting and unanticipated outcomes: (i) methylation at the C2 position of [Imm1+] affords a significantly higher vaporization enthalpy; (ii) in all cases, the [beti-] anion served to lower the enthalpy of vaporization relative to [Tf2N-]. The widespread availability of the apparatus required for these measurements coupled with the ease of automation suggests the broad potential of this methodology for determining this critical parameter in a multitude of ILs.

  4. Disordered eating, menstrual disturbances, and low bone mineral density in dancers: a systematic review.

    PubMed

    Hincapié, Cesar A; Cassidy, J David

    2010-11-01

    To assemble and synthesize the best evidence on the epidemiology, diagnosis, prognosis, treatment, and prevention of disordered eating, menstrual disturbances, and low bone mineral density in dancers. Medline, CINAHL, PsycINFO, Embase, and other electronic databases were searched from 1966 to 2010 using key words such as "dance," "dancer," "dancing," "eating disorders," "menstruation disturbances," and "bone density." In addition, the reference lists of relevant studies were examined, specialized journals were hand-searched, and the websites of major dance associations were scanned for relevant information. Citations were screened for relevance using a priori criteria, and relevant studies were critically reviewed for scientific merit by the best evidence synthesis method. After 2748 abstracts were screened, 124 articles were reviewed, and 23 (18.5%) of these were accepted as scientifically admissible (representing 19 unique studies). Data from accepted studies were abstracted into evidence tables relating to prevalence and associated factors; incidence and risk factors; diagnosis; and prevention of disordered eating, menstrual disturbances, and/or low bone mineral density in dancers. The scientifically admissible studies consisted of 13 (68%) cross-sectional studies and 6 (32%) cohort studies. Disordered eating and menstrual disturbances are common in dancers. The lifetime prevalence of any eating disorder was 50% in professional dancers, while the point prevalence ranged between 13.6% and 26.5% in young student dancers. In their first year of intensive dance training, 32% of university-level dancers developed a menstrual disturbance. The incidence of disordered eating and low bone mineral density in dancers is unknown. Several potential risk factors are suggested by the literature, but there is little compelling evidence for any of these. There is preliminary evidence that multifaceted sociocultural prevention strategies may help decrease the incidence of

  5. Sensitive life detection strategies for low-biomass environments: optimizing extraction of nucleic acids adsorbing to terrestrial and Mars analogue minerals.

    PubMed

    Direito, Susana O L; Marees, Andries; Röling, Wilfred F M

    2012-07-01

    The adsorption of nucleic acids to mineral matrixes can result in low extraction yields and negatively influences molecular microbial ecology studies, in particular for low-biomass environments on Earth and Mars. We determined the recovery of nucleic acids from a range of minerals relevant to Earth and Mars. Clay minerals, but also other silicates and nonsilicates, showed very low recovery (< 1%). Consequently, optimization of DNA extraction was directed towards clays. The high temperatures and acidic conditions used in some methods to dissolve mineral matrices proved to destruct DNA. The most efficient method comprised a high phosphate solution (P/EtOH; 1 M phosphate, 15% ethanol buffer at pH 8) introduced at the cell-lysing step in DNA extraction, to promote chemical competition with DNA for adsorption sites. This solution increased DNA yield from clay samples spiked with known quantities of cells up to nearly 100-fold. DNA recovery was also enhanced from several mineral samples retrieved from an aquifer, while maintaining reproducible DGGE profiles. DGGE profiles were obtained for a clay sample for which no profile could be generated with the standard DNA isolation protocol. Mineralogy influenced microbial community composition. The method also proved suitable for the recovery of low molecular weight DNA (< 1.5 kb). © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  6. Interactions of organic contaminants with mineral-adsorbed surfactants

    USGS Publications Warehouse

    Zhu, L.; Chen, B.; Tao, S.; Chiou, C.T.

    2003-01-01

    Sorption of organic contaminants (phenol, p-nitrophenol, and naphthalene) to natural solids (soils and bentonite) with and without myristylpyridinium bromide (MPB) cationic surfactant was studied to provide novel insight to interactions of contaminants with the mineral-adsorbed surfactant. Contaminant sorption coefficients with mineral-adsorbed surfactants, Kss, show a strong dependence on surfactant loading in the solid. At low surfactant levels, the Kss values increased with increasing sorbed surfactant mass, reached a maximum, and then decreased with increasing surfactant loading. The Kss values for contaminants were always higher than respective partition coefficients with surfactant micelles (Kmc) and natural organic matter (Koc). At examined MPB concentrations in water the three organic contaminants showed little solubility enhancement by MPB. At low sorbed-surfactant levels, the resulting mineral-adsorbed surfactant via the cation-exchange process appears to form a thin organic film, which effectively "adsorbs" the contaminants, resulting in very high Kss values. At high surfactant levels, the sorbed surfactant on minerals appears to form a bulklike medium that behaves essentially as a partition phase (rather than an adsorptive surface), with the resulting Kss being significantly decreased and less dependent on the MPB loading. The results provide a reference to the use of surfactants for remediation of contaminated soils/sediments or groundwater in engineered surfactant-enhanced washing.

  7. An Impact Origin for Surface Minerals on Ceres

    NASA Astrophysics Data System (ADS)

    Zolotov, M. Y.

    2013-12-01

    The dwarf planet Ceres is the largest body in the main asteroid belt with a hydrated dark rocky surface and an uncertain internal structure [1,2]. Spectra of Ceres in the near- and mid-infrared ranges show that surface materials may not contain abundant serpentine, saponite, sulfates, olivine, pyroxenes, and organic matter [2,3], which are common in carbonaceous chondrites. However, brucite, Mg carbonates, cronstedtite, and magnetite could be abundant and indicate aqueous processes [2,3]. The formation of abundant brucite, carbonates, and cronstedtite requires open-system low-temperature conditions characterized by elevated water/rock ratios and low fugacities of hydrogen and carbon dioxide. The observed mineralogy is more consistent with a near-surface origin than with a formation within Ceres or on planetesimals. The instability of aqueous solutions at the surface of Ceres implies mineral deposition during transient events of fluidal activity. But a warming of near-surface rocks by thermal processes in the interior requires dehydration of rocks, which is not consistent with the low density of Ceres. The lack of low-solubility sulfates in surface materials does not indicate percolation of interior fluids. Carbonate-bearing fluids may not percolate to the cold surface, especially if Ceres had undergone water-rock differentiation [1,4]. The lack of serpentine in surface materials does not indicate a formation of brucite through aqueous alteration of olivine-rich rocks. Though, the observed minerals could form in impact collisions of ice-rich targets and/or impactors. OH-bearing phases may condense from water-rich impact plumes [5]. Brucite and Mg carbonates could form through hydrolysis and carbonation of condensed MgO formed through evaporation of silicates. Apparently abundant carbonates may indicate an ample oxidation of organics. Ferric iron in magnetite and cronstedtite agrees with water-rich and oxidizing impact settings [5]. Turbulent and disequilibrium

  8. Mineral Reactions in Shale Gas Reservoirs: Barite Scale Formation from Reusing Produced Water As Hydraulic Fracturing Fluid.

    PubMed

    Paukert Vankeuren, Amelia N; Hakala, J Alexandra; Jarvis, Karl; Moore, Johnathan E

    2017-08-15

    Hydraulic fracturing for gas production is now ubiquitous in shale plays, but relatively little is known about shale-hydraulic fracturing fluid (HFF) reactions within the reservoir. To investigate reactions during the shut-in period of hydraulic fracturing, experiments were conducted flowing different HFFs through fractured Marcellus shale cores at reservoir temperature and pressure (66 °C, 20 MPa) for one week. Results indicate HFFs with hydrochloric acid cause substantial dissolution of carbonate minerals, as expected, increasing effective fracture volume (fracture volume + near-fracture matrix porosity) by 56-65%. HFFs with reused produced water composition cause precipitation of secondary minerals, particularly barite, decreasing effective fracture volume by 1-3%. Barite precipitation occurs despite the presence of antiscalants in experiments with and without shale contact and is driven in part by addition of dissolved sulfate from the decomposition of persulfate breakers in HFF at reservoir conditions. The overall effect of mineral changes on the reservoir has yet to be quantified, but the significant amount of barite scale formed by HFFs with reused produced water composition could reduce effective fracture volume. Further study is required to extrapolate experimental results to reservoir-scale and to explore the effect that mineral changes from HFF interaction with shale might have on gas production.

  9. Methyl t-Butyl Ether Mineralization in Surface-Water Sediment Microcosms under Denitrifying Conditions

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.; Landmeyer, J.E.

    2001-01-01

    Mineralization of [U-14C] methyl t-butyl ether (MTBE) to 14CO2 without accumulation of t-butyl alcohol (TBA) was observed in surface-water sediment microcosms under denitrifying conditions. Methanogenic activity and limited transformation of MTBE to TBA were observed in the absence of denitrification. Results indicate that bed sediment microorganisms can effectively degrade MTBE to nontoxic products under denitrifying conditions.

  10. Water and Carbon Dioxide Adsorption at Olivine Surfaces

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kerisit, Sebastien N.; Bylaska, Eric J.; Felmy, Andrew R.

    2013-11-14

    Plane-wave density functional theory (DFT) calculations were performed to simulate water and carbon dioxide adsorption at the (010) surface of five olivine minerals, namely, forsterite (Mg2SiO4), calcio-olivine (Ca2SiO4), tephroite (Mn2SiO4), fayalite (Fe2SiO4), and Co-olivine (Co2SiO4). Adsorption energies per water molecule obtained from energy minimizations varied from -78 kJ mol-1 for fayalite to -128 kJ mol-1 for calcio-olivine at sub-monolayer coverage and became less exothermic as coverage increased. In contrast, carbon dioxide adsorption energies at sub-monolayer coverage ranged from -20 kJ mol-1 for fayalite to -59 kJ mol-1 for calcio-olivine. Therefore, the DFT calculations show a strong driving force for carbonmore » dioxide displacement by water at the surface of all olivine minerals in a competitive adsorption scenario. Additionally, adsorption energies for both water and carbon dioxide were found to be more exothermic for the alkaline-earth (AE) olivines than for the transition-metal (TM) olivines and to not correlate with the solvation enthalpies of the corresponding divalent cations. However, a correlation was obtained with the charge of the surface divalent cation indicating that the more ionic character of the AE cations in the olivine structure relative to the TM cations leads to greater interactions with adsorbed water and carbon dioxide molecules at the surface and thus more exothermic adsorption energies for the AE olivines. For calcio-olivine, which exhibits the highest divalent cation charge of the five olivines, ab initio molecular dynamics simulations showed that this effect leads both water and carbon dioxide to react with the surface and form hydroxyl groups and a carbonate-like species, respectively.« less

  11. Enthalpy Costs of Making and Breaking Bonds: A Game of Generating Molecules with Proper Lewis Structures

    ERIC Educational Resources Information Center

    Bell, Peter T.; Adkins, Alyssa D.; Gamble, Rex J.; Schultz, Linda D.

    2009-01-01

    "Enthalpy Costs" is a simple card game created to assist students in developing proper Lewis structure drawing skills. Score keeping is accomplished by tracking the enthalpy changes associated with bond-making and bond-breaking processes during formation of molecules represented by proper Lewis structures. Playing the game requires the student to…

  12. Enthalpy measurement of coal-derived liquids. Combined quarterly technical progress reports, April-June 1979 and July-September 1979. [Effect of association

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kidnay, A.J.; Yesavage, V.F.

    1979-01-01

    Enthalpy measurements on a coal-derived naphtha and middle distillate, both produced by the SRC-II process, were made using flow calorimetry. The accuracy of the measurements, as reported by Omid, was within +- 1% of the measured enthalpy differences, ..delta..H. Experimental data for the naphtha were obtained over a pressure range of 100-300 psia and temperatures from 148/sup 0/ to 456/sup 0/F. The middle distillate enthalpy measurements were made in the pressure and temperature ranges of 130 to 1000 psia, and 157/sup 0/ to 675/sup 0/F, respectively. The methods of prediction of enthalpy developed for petroleum fractions were unsatisfactory when appliedmore » to the above data. A negative bias was observed in the predicted enthalpy values for several of the coal-liquids. Based on these results, it was theorized that the high experimental enthalpy values for coal-liquids were due to an energy of association attributed, primarily, to hydrogen-bonding effects. The petroleum-fraction enthalpy correlations were then tested on the experimental data for pure compounds, both associating and non-associating. The predicted values compared very well with the experimental results for non-associating model compounds. However, for associating model compounds the predicted enthalpy values were considerably lower than their experimental data. This served to confirm the basic premise that the high experimental enthalpy values, for model compounds and coal liquids, were a direct consequence of an energy of association attributed, primarily, to hydrogen-bonding effects.« less

  13. Geochemistry of mineral waters and associated gases of the Sakhalin Island (Far East of Russia)

    NASA Astrophysics Data System (ADS)

    Chelnokov, George A.; Bragin, Ivan V.; Kharitonova, Natalia A.

    2018-04-01

    Isotopic and chemical data on the mineral water, mud volcanoes fluid and associated gases from the biggest Russian island Sakhalin, together with previous stable isotope data (d18O, dD, 13C), allow elucidation of their origin and general evolution. The water fluid circulation is mainly related to marine environment inducing three distinct types: Na-HCO3-Cl alkali carbonate groundwaters, Na-Cl-HCO3 highly evolved saline and Na-Cl mature groundwaters, indicating different evolution. Chemical evolution of groundwater on Sakhalin Island demonstrated cation exchange and salinization as dominant evolutionary pathways. Isotopic composition of groundwaters varies from meteoric to metamorphic waters. These metamorphic waters consist of water hydration from the clay and seawater are traced in fluids of Yuzhno-Sakhalin mud volcano despite modification by mixing with meteoric waters and water-rock interaction processes. Fault systems that define the areas of highly mineralized water circulation appear to play a major role in the CO2 migration to the surface and CH4 generation. The δ13C(CO2) values have pointed that gas phase in high-pCO2 waters mostly consists of mantle-derived CO2. The carbon isotope signature of methane δ13C(CH4) and δD(CH4) indicates its distinct origin which is specified by tectonics. Methane manifestation in the south of the Sakhalin Island is mainly related to thermogenic reservoirs as they are more often dislocate by tectonics, and crossed by active and permeable faults. The sources of biogenous methane in the north of Sakhalin Island is related to younger and shallower reservoirs, and less affected by tectonic processes. The determinations of 222Rn have allowed observing that maximal radon flux is associated with high pCO2 waters.

  14. Entropy–enthalpy transduction caused by conformational shifts can obscure the forces driving protein–ligand binding

    PubMed Central

    Fenley, Andrew T.; Muddana, Hari S.; Gilson, Michael K.

    2012-01-01

    Molecular dynamics simulations of unprecedented duration now can provide new insights into biomolecular mechanisms. Analysis of a 1-ms molecular dynamics simulation of the small protein bovine pancreatic trypsin inhibitor reveals that its main conformations have different thermodynamic profiles and that perturbation of a single geometric variable, such as a torsion angle or interresidue distance, can select for occupancy of one or another conformational state. These results establish the basis for a mechanism that we term entropy–enthalpy transduction (EET), in which the thermodynamic character of a local perturbation, such as enthalpic binding of a small molecule, is camouflaged by the thermodynamics of a global conformational change induced by the perturbation, such as a switch into a high-entropy conformational state. It is noted that EET could occur in many systems, making measured entropies and enthalpies of folding and binding unreliable indicators of actual thermodynamic driving forces. The same mechanism might also account for the high experimental variance of measured enthalpies and entropies relative to free energies in some calorimetric studies. Finally, EET may be the physical mechanism underlying many cases of entropy–enthalpy compensation. PMID:23150595

  15. Titration calorimetry of anesthetic-protein interaction: negative enthalpy of binding and anesthetic potency.

    PubMed Central

    Ueda, I; Yamanaka, M

    1997-01-01

    Anesthetic potency increases at lower temperatures. In contrast, the transfer enthalpy of volatile anesthetics from water to macromolecules is usually positive. The transfer decreases at lower temperature. It was proposed that a few selective proteins bind volatile anesthetics with negative delta H, and these proteins are involved in signal transduction. There has been no report on direct estimation of binding delta H of anesthetics to proteins. This study used isothermal titration calorimetry to analyze chloroform binding to bovine serum albumin. The calorimetrically measured delta H cal was -10.37 kJ.mol-1. Thus the negative delta H of anesthetic binding is not limited to signal transduction proteins. The binding was saturable following Fermi-Dirac statistics and is characterized by the Langmuir adsorption isotherms, which is interfacial. The high-affinity association constant, K, was 2150 +/- 132 M-1 (KD = 0.47 mM) with the maximum binding number, Bmax = 3.7 +/- 0.2. The low-affinity K was 189 +/- 3.8 M-1 (KD = 5.29 mM), with a Bmax of 13.2 +/- 0.3. Anesthetic potency is a function of the activity of anesthetic molecules, not the concentration. Because the sign of delta H determines the temperature dependence of distribution of anesthetic molecules, it is irrelevant to the temperature dependence of anesthetic potency. PMID:9083685

  16. Temperature dependences of saturated vapor pressure and the enthalpy of vaporization of n-pentyl esters of dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Portnova, S. V.; Krasnykh, E. L.; Levanova, S. V.

    2016-05-01

    The saturated vapor pressures and enthalpies of vaporization of n-pentyl esters of linear C2-C6 dicarboxylic acids are determined by the transpiration method in the temperature range of 309.2-361.2 K. The dependences of enthalpies of vaporization on the number of carbon atoms in the molecule and on the retention indices have been determined. The predictive capabilities of the existing calculation schemes for estimation of enthalpy of vaporization of the studied compounds have been analyzed.

  17. 210Po and 238U isotope concentrations in commercial bottled mineral water samples in Spain and their dose contribution.

    PubMed

    Díaz-Francés, I; Mantero, J; Manjón, G; Díaz, J; García-Tenorio, R

    2013-09-01

    (210)Po is a naturally occurring radionuclide, belonging to the uranium series, which is present in minute amounts in the different environmental compartments (water, soil, biota). Through its route along the trophic chain, it can be incorporated in the human body via ingestion of waters and/or food. This radionuclide is highly radiotoxic, being one of the main contributors to the committed effective dose via ingestion by the general population. In this work, the contribution of this radionuclide to the committed effective dose received by the Spanish population via consumption of bottled mineral waters is evaluated. With this end, the (210)Po activity concentrations in a total of 32 different commercial bottled mineral waters have been determined by alpha-particle spectrometry. The determined contribution is also compared with the contributions of other natural radionuclides such as (234)U and (238)U.

  18. Group vector space method for estimating enthalpy of vaporization of organic compounds at the normal boiling point.

    PubMed

    Wenying, Wei; Jinyu, Han; Wen, Xu

    2004-01-01

    The specific position of a group in the molecule has been considered, and a group vector space method for estimating enthalpy of vaporization at the normal boiling point of organic compounds has been developed. Expression for enthalpy of vaporization Delta(vap)H(T(b)) has been established and numerical values of relative group parameters obtained. The average percent deviation of estimation of Delta(vap)H(T(b)) is 1.16, which show that the present method demonstrates significant improvement in applicability to predict the enthalpy of vaporization at the normal boiling point, compared the conventional group methods.

  19. Application of enthalpy model for floating zone silicon crystal growth

    NASA Astrophysics Data System (ADS)

    Krauze, A.; Bergfelds, K.; Virbulis, J.

    2017-09-01

    A 2D simplified crystal growth model based on the enthalpy method and coupled with a low-frequency harmonic electromagnetic model is developed to simulate the silicon crystal growth near the external triple point (ETP) and crystal melting on the open melting front of a polycrystalline feed rod in FZ crystal growth systems. Simulations of the crystal growth near the ETP show significant influence of the inhomogeneities of the EM power distribution on the crystal growth rate for a 4 in floating zone (FZ) system. The generated growth rate fluctuations are shown to be larger in the system with higher crystal pull rate. Simulations of crystal melting on the open melting front of the polycrystalline rod show the development of melt-filled grooves at the open melting front surface. The distance between the grooves is shown to grow with the increase of the skin-layer depth in the solid material.

  20. Low-intensity lasers, modern filling materials, and bonding systems influence on mineral metabolism of hard dental tissues

    NASA Astrophysics Data System (ADS)

    Kunin, Anatoly A.; Yesaulenko, I. E.; Zoibelmann, M.; Pankova, Svetlana N.; Ippolitov, Yu. A.; Oleinik, Olga I.; Popova, T. A.; Koretskaya, I. V.; Shumilovitch, Bogdan R.; Podolskaya, Elana E.

    2001-10-01

    One of the main reasons of low quality filling is breaking Ca-P balance in hard tissues. Our research was done with the purpose of studying the influence of low intensity lasers, diodic radiation, the newest filling and bonding systems on the processes of mineral metabolism in hard dental tissues while filling a tooth. 250 patients having caries and its compli-cations were examined and treated. Our complex research included: visual and instrumental examination, finding out the level of oral cavity hygiene, acid enamel biopsy, scanning electronic microscopy and X-ray spectrum microanalysis. Filling processes may produce a negative effect on mineral metabolism of hard dental tissues the latter is less pronounced when applying fluoride-containing filling materials with bonding systems. It has also been found that bonding dentin and enamel systems are designed for both a better filling adhesion (i.e. mechanical adhesion) and migration of useful microelements present in them by their sinking into hard dental tissues (i.e. chemical adhesion). Our research showed a positive influence of low intensity laser and diodic beams accompanying the use of modern filling and bonding systems on mineral metabolism of hard dental tissues.

  1. Structure, dynamics and stability of water/scCO 2/mineral interfaces from ab initio molecular dynamics simulations

    DOE PAGES

    Lee, Mal -Soon; Peter McGrail, B.; Rousseau, Roger; ...

    2015-10-12

    Here, the interface between a solid and a complex multi-component liquid forms a unique reaction environment whose structure and composition can significantly deviate from either bulk or liquid phase and is poorly understood due the innate difficulty to obtain molecular level information. Feldspar minerals, as typified by the Ca-end member Anorthite, serve as prototypical model systems to assess the reactivity and ion mobility at solid/water-bearing supercritical fluid (WBSF) interfaces due to recent X-ray based measurements that provide information on water-film formation, and cation vacancies at these surfaces. Using density functional theory based molecular dynamics, which allows the evaluation of reactivitymore » and condensed phase dynamics on equal footing, we report on the structure and dynamics of water nucleation and surface aggregation, carbonation and Ca mobilization under geologic carbon sequestration scenarios (T = 323 K and P = 90 bar). We find that water has a strong enthalpic preference for aggregation on a Ca-rich, O-terminated anorthite (001) surface, but entropy strongly hinders the film formation at very low water concentrations. Carbonation reactions readily occur at electron-rich terminal Oxygen sites adjacent to cation vacancies, when in contact with supercritical CO 2. Cation vacancies of this type can form readily in the presence of a water layer that allows for facile and enthalpicly favorable Ca 2+ extraction and solvation. Apart from providing unprecedented molecular level detail of a complex three component (mineral, water and scCO 2) system), this work highlights the ability of modern capabilities of AIMD methods to begin to qualitatively and quantitatively address structure and reactivity at solid-liquid interfaces of high chemical complexity. This work was supported by the US Department of Energy, Office of Fossil Energy (M.-S. L., B. P. M. and V.-A. G.) and the Office of Basic Energy Science, Division of Chemical Sciences

  2. Molar volume, excess enthalpy, and Prigogine-Defay ratio of some silicate glasses with different (P,T) histories.

    PubMed

    Wondraczek, Lothar; Behrens, Harald

    2007-10-21

    Structural relaxation in silicate glasses with different (p,T) histories was experimentally examined by differential scanning calorimetry and measurements of molar volume under ambient pressure. Temperature and pressure-dependent rates of changes in molar volume and generation of excess enthalpy were determined for sodium trisilicate, soda lime silicate, and sodium borosilicate (NBS) compositions. From the derived data, Prigogine-Defay ratios are calculated and discussed. Changes of excess enthalpy are governed mainly by changes in short-range structure, as is shown for NBS where boron coordination is highly sensitive to pressure. For all three glasses, it is shown how the relaxation functions that underlie volume, enthalpy, and structural relaxation decouple for changes in cooling rates and pressure of freezing, respectively. The magnitude of the divergence between enthalpy and volume may be related to differences in structural sensitivity to changes in the (p,V,T,t) space on different length scales. The findings suggest that the Prigogine-Defay ratio is related to the magnitude of the discussed decoupling effect.

  3. Origin of secondary sulfate minerals on active andesitic stratovolcanoes

    USGS Publications Warehouse

    Zimbelman, D.R.; Rye, R.O.; Breit, G.N.

    2005-01-01

    Sulfate minerals in altered rocks on the upper flanks and summits of active andesitic stratovolcanoes result from multiple processes. The origin of these sulfates at five active volcanoes, Citlalte??petl (Mexico), and Mount Adams, Hood, Rainier, and Shasta (Cascade Range, USA), was investigated using field observations, petrography, mineralogy, chemical modeling, and stable-isotope data. The four general groups of sulfate minerals identified are: (1) alunite group, (2) jarosite group, (3) readily soluble Fe- and Al-hydroxysulfates, and (4) simple alkaline-earth sulfates such as anhydrite, gypsum, and barite. Generalized assemblages of spatially associated secondary minerals were recognized: (1) alunite+silica??pyrite??kaolinite?? gypsum??sulfur, (2) jarosite+alunite+silica; (3) jarosite+smectite+silica??pyrite, (4) Fe- and Al-hydroxysulfates+silica, and (5) simple sulfates+silica??Al-hydroxysulfates??alunite. Isotopic data verify that all sulfate and sulfide minerals and their associated alteration assemblages result largely from the introduction of sulfur-bearing magmatic gases into meteoric water in the upper levels of the volcanoes. The sulfur and oxygen isotopic data for all minerals indicate the general mixing of aqueous sulfate derived from deep (largely disproportionation of SO2 in magmatic vapor) and shallow (oxidation of pyrite or H2S) sources. The hydrogen and oxygen isotopic data of alunite indicate the mixing of magmatic and meteoric fluids. Some alunite-group minerals, along with kaolinite, formed from sulfuric acid created by the disproportionation of SO2 in a condensing magmatic vapor. Such alunite, observed only in those volcanoes whose interiors are exposed by erosion or edifice collapse, may have ??34S values that reflect equilibrium (350??50 ??C) between aqueous sulfate and H2S. Alunite with ??34S values indicating disequilibrium between parent aqueous sulfate and H2S may form from aqueous sulfate created in higher level low

  4. Bond dissociation enthalpies of a pinoresinol lignin model compound

    Treesearch

    Thomas Elder

    2014-01-01

    ABSTRACT: The pinoresinol unit is one of the principal interunit linkages in lignin. As such, its chemistry and properties are of major importance in understanding the behavior or the polymer. This work examines the homolytic cleavage of the pinoresinol system, representing the initial step in thermal degradation. The bond dissociation enthalpy of this reaction has...

  5. Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

    ERIC Educational Resources Information Center

    Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

    2007-01-01

    A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

  6. Mineral Property Management - Division of Mining, Land, and Water

    Science.gov Websites

    Mineral Property Management This section in the division maintains the records for mineral property rights established under state laws and regulations. The timely maintenance of property right records is fundamental to the mineral industry operating. Property right records must be current and up-to-date for title

  7. Rare earth elements in Hamersley BIF minerals

    NASA Astrophysics Data System (ADS)

    Alibert, Chantal

    2016-07-01

    Minerals from the Hamersley banded iron formation, Western Australia, were analyzed for Y and rare earth elements (YREEs) by laser ablation ICP-MS to investigate diagenetic pathways, from precursor phases to BIF minerals. One group of apatites carries the seawater REE signature, giving evidence that P and REEs, thoroughly scavenged from the water column by Si-ferrihydrite particles, were released upon microbial Fe3+ reductive dissolution of Si-ferrihydrite in pore-water and finally sequestered mainly in authigenic apatite. The absence of fractionation between apatite and seawater suggests that REE were first incorporated into an amorphous calcium phosphate as fully hydrated cations, i.e. as outer-sphere complexes. The iron oxides and carbonates carry only a small fraction of the whole-rock REE budget. Their REE patterns are distinctly enriched in Yb and show some M-type tetrad effect consistent with experimental Kd(REE) between solid and saline solution with low carbonate ion concentrations. It is deduced that hematite formed at an incipient stage of Fe2+-catalyzed dissolution of Si-ferrihydrite, via a dissolution-reprecipitation pathway. The REE pattern of greenalite, found as sub-micron particles in quartz in a chert-siderite sample, is consistent with its authigenic origin by precipitation in pore-water after dissolution of a small amount of Si-ferrihydrite. Magnetite carries very low YREEs (ppb-level), has an homogeneous pattern distinctly enriched in the mid-REEs compared to hematite, and includes a late population depleted in light-REEs, Ba and As. Magnetite forming aggregates and massive laminae is tentatively interpreted as reflecting some fluid-aided hematite-magnetite re-equilibration or transformation at low-grade metamorphic temperatures.

  8. Amphiphilic polypeptides as a bifunctional template in the mineralization of calcium carbonate at the air/water interface.

    PubMed

    Cao, Heng; Lin, Guoqiang; Yao, Jinrong; Shao, Zhengzhong

    2013-05-01

    A well-defined amphiphilic polypeptide, poly(glutamic acid)22 -block-poly(alanine)8 (PGlu22 -b-PAla8 ), which plays the roles of both soluble (functional) additive and insoluble (structural) matrix, is employed to mediate the mineralization of CaCO3 at the air/water interface. X-ray diffraction (XRD) and Raman spectroscopy, for example, show that the polymorph of CaCO3 particles obtained is calcite. The observations from SEM and TEM suggest that PGlu22 -b-PAla8 initiates the amorphous precursor phase and heterogeneous nucleation of CaCO3 at the air/water interface, while temporarily stabilizes the gelatinous precursors as a process-directing agent; nevertheless, the initial concentration of Ca(2+) controls the procedure of crystallization and the final morphology of CaCO3 particles. Such "bifunctional" amphiphilic-polypeptide-regulated mineralization at the air/water interface may be applied to the synthesis of many kinds of symmetrical inorganic/organic hybrids. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Risk Factors for Low Bone Mineral Density in Individuals Residing in a Facility for the People with Intellectual Disability

    ERIC Educational Resources Information Center

    Jaffe, J. S.; Timell, A. M.; Elolia, R.; Thatcher, S. S.

    2005-01-01

    Background: Individuals with intellectual disability (ID) are known to have a high prevalence of both low bone mineral density (BMD) and fractures with significant attendant morbidity. Effective strategies aimed at reducing fractures will be facilitated by the identification of predisposing risk factors. Methods: Bone mineral density was measured…

  10. CO2 hydrate nucleation kinetics enhanced by an organo-mineral complex formed at the montmorillonite-water interface.

    PubMed

    Kyung, Daeseung; Lim, Hyung-Kyu; Kim, Hyungjun; Lee, Woojin

    2015-01-20

    In this study, we investigated experimentally and computationally the effect of organo-mineral complexes on the nucleation kinetics of CO2 hydrate. These complexes formed via adsorption of zwitter-ionic glycine (Gly-zw) onto the surface of sodium montmorillonite (Na-MMT). The electrostatic attraction between the −NH3(+) group of Gly-zw, and the negatively charged Na-MMT surface, provides the thermodynamic driving force for the organo-mineral complexation. We suggest that the complexation of Gly-zw on the Na-MMT surface accelerates CO2 hydrate nucleation kinetics by increasing the mineral–water interfacial area (thus increasing the number of effective hydrate-nucleation sites), and also by suppressing the thermal fluctuation of solvated Na(+) (a well-known hydrate formation inhibitor) in the vicinity of the mineral surface by coordinating with the −COO(–) groups of Gly-zw. We further confirmed that the local density of hydrate-forming molecules (i.e., reactants of CO2 and water) at the mineral surface (regardless of the presence of Gly-zw) becomes greater than that of bulk phase. This is expected to promote the hydrate nucleation kinetics at the surface. Our study sheds new light on CO2 hydrate nucleation kinetics in heterogeneous marine environments, and could provide knowledge fundamental to successful CO2 sequestration under seabed sediments.

  11. In vitro evaluation of natural thermal mineral waters in human keratinocyte cells: a preliminary study

    NASA Astrophysics Data System (ADS)

    Karagülle, Müfit Zeki; Karagülle, Mine; Kılıç, Songül; Sevinç, Hakan; Dündar, Cihat; Türkoğlu, Murat

    2018-06-01

    We aimed to test the anti-inflammatory and angiogenic properties of two different thermal waters at the cellular level in human keratinocyte cells in the present study. Two different thermal waters, thermo-mineral BJ1 (Bursa, Turkey) and oligomineral BG (Bolu, Turkey), were tested in human keratinocyte (HaCaT) cell line. HaCaT cells were incubated for 3 days with thermal waters; RNA isolation was carried out in the treated and untreated cells. The gene expressions of TNFα, IL-1α, and VEGF were measured using the RT-qPCR. The tested thermal waters significantly decreased the expression of IL-1α (BJ1 93% p = 0.0024 and BG 38% p = 0.0303). BJ1 and BG thermal waters downregulated the expression of TNFα (59% p = 0.0001 and 23% p = 0.0238 respectively). Furthermore, BJ1 and BG significantly downregulated the gene expression of VEGF (98% p = 0.0430 and 15% p = 0.0120). The observed decrease in the gene expression of TNFα and IL1α could be interpreted as an anti-inflammatory effect of mineral waters on HaCaT cells. Moreover, the suppressed VEGF expression might be an indicator of the antiangiogenic effect on human keratinocytes. Therefore, we hypothesized that depending on their specific chemical composition such as silica (128 mg/L) in BJ1 and hydrogen sulfide (1.2 mg/L) in BG, thermal waters suppress pro-inflammatory cytokines and angiogenic growth factor. These preliminary findings might give insight on the underlying mechanisms of the therapeutic benefits observed in some skin diseases such as rosacea and psoriasis.

  12. Predicting glass-to-glass and liquid-to-liquid phase transitions in supercooled water using classical nucleation theory

    NASA Astrophysics Data System (ADS)

    Tournier, Robert F.

    2018-01-01

    Glass-to-glass and liquid-to-liquid phase transitions are observed in bulk and confined water, with or without applied pressure. They result from the competition of two liquid phases separated by an enthalpy difference depending on temperature. The classical nucleation equation of these phases is completed by this quantity existing at all temperatures, a pressure contribution, and an enthalpy excess. This equation leads to two homogeneous nucleation temperatures in each liquid phase; the first one (Tn- below Tm) being the formation temperature of an "ordered" liquid phase and the second one corresponding to the overheating temperature (Tn+ above Tm). Thermodynamic properties, double glass transition temperatures, sharp enthalpy and volume changes are predicted in agreement with experimental results. The first-order transition line at TLL = 0.833 × Tm between fragile and strong liquids joins two critical points. Glass phase above Tg becomes "ordered" liquid phase disappearing at TLL at low pressure and at Tn+ = 1.302 × Tm at high pressure.

  13. Problem-Based Learning in Teaching Chemistry: Enthalpy Changes in Systems

    ERIC Educational Resources Information Center

    Ayyildiz, Yildizay; Tarhan, Leman

    2018-01-01

    Background: Problem-based learning (PBL) as a teaching strategy has recently become quite widespread in especially chemistry classes. Research has found that students, from elementary through college, have many alternative conceptions regarding "enthalpy changes in systems." Although there are several studies focused on identifying…

  14. Iron Sulfide Minerals Record Microbe-Mineral Interactions in Anoxic Environments

    NASA Astrophysics Data System (ADS)

    Picard, A.; Gartman, A.; Cosmidis, J.; Clarke, D. R.; Girguis, P. R.

    2017-12-01

    The precipitation of most minerals in low-temperature environments on Earth is directly or indirectly influenced by the presence of organic substances and/or microbial biomass. Notably, the influence of microorganisms on the formation of Mn and Fe oxides/oxyhydroxides at the surface of the Earth has been well characterized (Chan et al., 2011; Estes et al., 2017). However, an oxygenated atmosphere is a unique feature of planet Earth. It is therefore critical for the search of life on other planetary bodies to characterize microbe-mineral interactions that form in anoxic conditions. Here we explore the role of microorganisms on the formation of iron sulfide minerals, which form under anoxic conditions. On modern Earth, sulfate-reducing microorganisms (SRM) are the major source of dissolved sulfide in low-temperature sedimentary environments. We experimentally demonstrate that SRM play a role in the nucleation and growth of iron sulfide minerals by acting as organic templates. The physical characteristics of the resulting minerals are different from those formed under abiotic conditions. Moreover, upon forming, iron sulfide minerals become associated with organic carbon, producing a potential organo-mineral signature. We also evaluate how the presence of various organic substances affect the formation of abiotic minerals and how this could produce false biosignatures that could be mistaken as biogenic minerals. Chan, C.S., Fakra, S.C., Emerson, D., Fleming, E.J. and Edwards, K.J. (2011) Lithotrophic iron-oxidizing bacteria produce organic stalks to control mineral growth: implications for biosignature formation. Isme Journal 5, 717-727. Estes, E.R., Andeer, P.F., Nordlund, D., Wankel, S.D. and Hansel, C.M. (2017) Biogenic manganese oxides as reservoirs of organic carbon and proteins in terrestrial and marine environments. Geobiology 15, 158-172.

  15. Oxygen and carbon isotope ratios of hydrothermal minerals from Yellowstone drill cores

    USGS Publications Warehouse

    Sturchio, N.C.; Keith, T.E.C.; Muehlenbachs, K.

    1990-01-01

    Oxygen and carbon isotope ratios were measured for hydrothermal minerals (silica, clay and calcite) from fractures and vugs in altered rhyolite, located between 28 and 129 m below surface (in situ temperatures ranging from 81 to 199??C) in Yellowstone drill holes. The purpose of this study was to investigate the mechanism of formation of these minerals. The ??18O values of the thirty-two analyzed silica samples (quartz, chalcedony, ??-cristobalite, and ??-cristobalite) range from -7.5 to +2.8???. About one third of the silica 7samples have ??18O values that are consistent with isotopic equilibrium with present thermal waters; most of the other silica samples appear to have precipitated from water enriched in 18O (up to 4.7???) relative to present thermal water, assuming precipitation at present in situ temperatures. Available data on fluid-inclusion homogenization temperatures in hydrothermal quartz indicate that silica precipitation occurred mostly at temperatures above those measured during drilling and imply that 15O enrichments in water during silica precipitation were generally larger than those estimated from present conditions. Similarly, clay minerals (celadonite and smectite) have ??18O values higher (by 3.5 to 7.9???) than equilibrium values under present conditions. In contrast, all eight analyzed calcite samples are close to isotopic equilibrium with present thermal waters. The frequent incidence of apparent 18O enrichment in thermal water from which the hydrothermal minerals precipitated may indicate that a higher proportion of strongly 18O-enriched deep hydrothermal fluid once circulated through shallow portions of the Yellowstone system, or that a recurring transient 18O-enrichment effect occurs at shallow depths and is caused either by sudden decompressional boiling or by isotopic exchange at low water/rock ratios in new fractures. The mineralogy and apparent 18O enrichments of hydrothermal fracture-filling minerals are consistent with deposition

  16. [The environmental conditions of the Kavkazskie Mineralnye Vody (Caucasian Mineral Waters) health resort region, methods for their monitoring and improvement].

    PubMed

    Evseeva, M M; Rud', N Iu; Pershin, I M

    2012-01-01

    This paper describes the unique environmental conditions of the Kavkazskie Mineralnye Vody (Caucasian Mineral Waters) health resort region with special reference to its paramount importance for the national interests of Russia. It is emphasized, however, that the environmental conditions in the region under consideration are far from being satisfactory. In connection with this, the authors point out to the necessity of expanding areas of protective forest stands and prohibition of the implementation of new building projects in the frontal mountain sanitary zones; they draw special attention to the potential danger of degradation of mineral water springs under the influence of changes in the distribution of vertical hydraulic gradients in the upper part of the lithosphere leading to the deterioration of their composition and the contamination of ground and surface waters with municipal and domestic effluents. Special attention is given to the harm and impermissibility of illegal extraction of mineral waters from producing wells. An original method for water quality control and estimation of the optimal production rate is proposed. The authors hypothesize the possible causes behind the discontinuation of mud formation at the Tambukan deposits and substantiate the necessity of using the resource-saving technologies for processing raw materials and urgent measures to eliminate the factors responsible for desalination and pollution of this mineral mud lake. It is concluded that strict state control should be exercised in the region by means of the introduction of the multilevel automated information system for round-the-clock environmental monitoring. The authors believe that only joint efforts of scientists, legislative and executive authorities can preserve Kavkazskie Mineralnye Vody health resort region for the future generations.

  17. Isothermal enthalpy relaxation of glassy 1,2,6-hexanetriol

    NASA Astrophysics Data System (ADS)

    Fransson, Å.; Bäckström, G.

    The isothermal enthalpy relaxation of glassy 1,2,6-hexanetriol has been measured at six temperatures. The relaxation time and the distribution parameters extracted from fits of the Williams-Watts relaxation function are compared with parameters obtained by other techniques and on other substances. A detailed comparison of the Williams-Watts and the Davidson-Cole relaxation functions is presented.

  18. U.S. Geological Survey Mineral Resources Program - Science Supporting Mineral Resource Stewardship

    USGS Publications Warehouse

    Kropschot, S.J.

    2007-01-01

    The United States is the world's largest user of mineral resources. We use them to build our homes and cities, fertilize our food crops, and create wealth that allows us to buy goods and services. Individuals rarely use nonfuel mineral resources in their natural state - we buy light bulbs, not the silica, soda ash, lime, coal, salt, tungsten, copper, nickel, molybdenum, iron, manganese, aluminum, and zinc used to convert electricity into light. The USGS Mineral Resources Program (MRP) is the sole Federal source of scientific information and unbiased research on nonfuel mineral potential, production, and consumption, as well as on the environmental effects of minerals. The MRP also provides baseline geochemical, geophysical, and mineral-deposit data used to understand environmental issues related to extraction and use of mineral resources. Understanding how minerals, water, plants, and organisms interact contributes to our understanding of the environment, which is essential for maintaining human and ecosystem health. To support creation of economic and national security policies in a global context, MRP collects and analyzes data on essential mineral commodities from around the world.

  19. Scenarios for low carbon and low water electric power plant ...

    EPA Pesticide Factsheets

    In the water-energy nexus, water use for the electric power sector is critical. Currently, the operational phase of electric power production dominates the electric sector's life cycle withdrawal and consumption of fresh water resources. Water use associated with the fuel cycle and power plant equipment manufacturing phase is substantially lower on a life cycle basis. An outstanding question is: how do regional shifts to lower carbon electric power mixes affect the relative contribution of the upstream life cycle water use? To test this, we examine a range of scenarios comparing a baseline with scenarios of carbon reduction and water use constraints using the MARKet ALlocation (MARKAL) energy systems model with ORD's 2014 U.S. 9-region database (EPAUS9r). The results suggest that moving toward a low carbon and low water electric power mix may increase the non-operational water use. In particular, power plant manufacturing water use for concentrating solar power, and fuel cycle water use for biomass feedstock, could see sharp increases under scenarios of high deployment of these low carbon options. Our analysis addresses the following questions. First, how does moving to a lower carbon electricity generation mix affect the overall regional electric power water use from a life cycle perspective? Second, how does constraining the operational water use for power plants affect the mix, if at all? Third, how does the life cycle water use differ among regions under

  20. Improving Drinking Water Quality by Remineralisation.

    PubMed

    Luptáková, Anna; Derco, Ján

    2015-01-01

    The reason of low mineral content in source water is its origin in poorly soluble mineral geological structures. There are many areas with very soft low-mineralised water around the world. All people involved in drinking water treatment as well as some public health experts and producers of chemicals used for water treatment may be interested in the study. Enrichment of drinking water by minerals including calcium and magnesium is very important particularly in regions where drinking water is prepared by desalination. The aim of this work was to study and intensify the recarbonization process. Half-calcined dolomite in combination with carbon dioxide constitutes the chemistry of the applied method. Advantages of using a fluidised bed reactor contributed also significantly to the process efficiency enhancement. Continuous input of carbon dioxide into the fluidised bed recarbonization reactor resulted in an increase in the recarbonization rate by about one order of magnitude compared with the process in without carbon dioxide addition. Very good fit of experimental data for hydrodynamic characteristics of fluidised bed was obtained using simple model based on the Richardson and Zaki expansion equation. The first order model describes kinetic data from the recarbonization process with a good accuracy. Higher recarbonization rates were observed with smaller particles of half-calcined dolomite.

  1. The potential influence of Asian and African mineral dust on ice, mixed-phase and liquid water clouds

    NASA Astrophysics Data System (ADS)

    Wiacek, A.; Peter, T.; Lohmann, U.

    2010-02-01

    This modelling study explores the availability of mineral dust particles as ice nuclei for interactions with ice, mixed-phase and liquid water clouds, also tracking the particles' history of cloud-processing. We performed 61 320 one-week forward trajectory calculations originating near the surface of major dust emitting regions in Africa and Asia using high-resolution meteorological analysis fields for the year 2007. Without explicitly modelling dust emission and deposition processes, dust-bearing trajectories were assumed to be those coinciding with known dust emission seasons. We found that dust emissions from Asian deserts lead to a higher potential for interactions with high clouds, despite being the climatologically much smaller dust emission source. This is due to Asian regions experiencing significantly more ascent than African regions, with strongest ascent in the Asian Taklimakan desert at ~25%, ~40% and 10% of trajectories ascending to 300 hPa in spring, summer and fall, respectively. The specific humidity at each trajectory's starting point was transported in a Lagrangian manner and relative humidities with respect to water and ice were calculated in 6-h steps downstream, allowing us to estimate the formation of liquid, mixed-phase and ice clouds. Practically none of the simulated air parcels reached regions where homogeneous ice nucleation can take place (T≲-40 °C) along trajectories that have not experienced water saturation first. By far the largest fraction of cloud forming trajectories entered conditions of mixed-phase clouds, where mineral dust will potentially exert the biggest influence. The majority of trajectories also passed through regions supersaturated with respect to ice but subsaturated with respect to water, where "warm" (T≳-40 °C) ice clouds may form prior to supercooled water or mixed-phase clouds. The importance of "warm" ice clouds and the general influence of dust in the mixed-phase cloud region are highly uncertain due to

  2. Variation in Surficial Hydrated Minerals on Large Low-Albedo Asteroids

    NASA Astrophysics Data System (ADS)

    Rivkin, Andrew S.; Emery, Joshua P.; Howell, Ellen S.

    2017-10-01

    Observations of asteroids in the 3-µm spectral region, where absorptions diagnostic for hydrated minerals are found, show low-albedo asteroid spectra can be classified into at least 3 groups (Takir et al. 2013, Rivkin et al. 2015). While definitions of these groups vary between authors, they hold in common a group with spectra like what we see for CM/CI meteorites, one group with spectra like that of Ceres, and a group with spectra that have been interpreted as ice frost. The relationship between these groups is not yet clear. One possibility is that the spectrum reflects (no pun intended) the formation location for the asteroids and that a given object is undifferentiated and homogeneous in the composition of its hydrated minerals. However, models of the thermal and chemical evolution of large, low-albedo asteroids suggests that differentiation may be more common than we had thought, and impacts could exhume once-deep layers or expose complicated mixes of salts and silicates (for instance, Castillo-Rogez et al. LPSC 2017 model of Ceres). In this case, we might expect variation in the 3-µm spectral region to be seen on the surfaces of some objects as they rotate. We will present evidence for such variation in the spectrum of two large asteroids, 704 Interamnia (306 km diameter) and 324 Bamberga (220 km diameter). In the first case, Interamnia’s spectrum seems to have a combination of Ceres- and CM/CI-like features and has aspects where one or another component is dominant, while Bamberga’s spectrum is not easily placed in previously-defined groups.

  3. Osteoporosis and Low Bone Mineral Density in Men with Testosterone Deficiency Syndrome.

    PubMed

    Gaffney, Christopher D; Pagano, Matthew J; Kuker, Adriana P; Stember, Doron S; Stahl, Peter J

    2015-10-01

    Testosterone deficiency syndrome (TDS) is a risk factor for low bone mineral density (BMD) and osteoporosis. Knowledge of the relationship between TDS and bone health, as well as the practical aspects of how to diagnose and treat low BMD, is therefore of practical importance to sexual medicine practitioners. The aim of this study was to review the physiologic basis and clinical evidence of the relationship between TDS and bone health; and to provide a practical, evidence-based algorithm for the diagnosis and management of low BMD in men with TDS. Method used was a review of relevant publications in PubMed. Pathophysiology of low BMD in TDS, morbidity, and mortality of osteoporosis in men, association between TDS and osteoporosis, indications for dual X-ray absorptiometry (DXA) scanning in TDS, evidence for testosterone replacement therapy (TRT) in men with osteoporosis, treatment for osteoporosis in the setting of TDS. Sex hormones play a pleomorphic role in maintenance of BMD. TDS is associated with increased risk of osteoporosis and osteopenia, both of which contribute to morbidity and mortality in men. DXA scanning is indicated in men older than 50 years with TDS, and in younger men with longstanding TDS. Men with TDS and osteoporosis should be treated with anti-osteoporotic agents and TRT should be highly considered. Men with osteopenia should be stratified by fracture risk. Those at high risk should be treated with anti-osteoporotic agents with strong consideration of TRT; while those at low risk should be strongly considered for TRT, which has a beneficial effect on BMD. Low BMD is a prevalent and treatable cause of morbidity and mortality in men with TDS. Utilization of a practical, evidence-based approach to diagnosis and treatment of low BMD in men with TDS enables sexual medicine practitioners to make a meaningful impact on patient quality of life and longevity. Gaffney CD, Pagano MJ, Kuker AP, Stember DS, and Stahl PJ. Osteoporosis and low bone mineral

  4. Effect of two microbial phytases on mineral availability and retention and bone mineral density in low-phosphorus diets for broilers.

    PubMed

    Chung, T K; Rutherfurd, S M; Thomas, D V; Moughan, P J

    2013-06-01

    1. The efficacy of supplementation of a low-phosphorus (low-P) maize-soyabean meal diet for broiler chickens with two different microbial (fungal and bacterial) phytases was examined. 2. Broiler chickens received a low-P maize-soyabean meal diet containing either no phytase or one of the two phytases included at one and two times the manufacturer's recommended inclusion level for 21 d. 3. Titanium dioxide was included in the diets as an indigestible marker. Excreta were collected quantitatively from d 18 to 21, and at the end of the study the birds were killed and ileal digesta and leg bone samples collected. 4. No differences were observed for body weight gain and feed intake or apparent metabolisable energy (AME) among all dietary treatment groups. 5. Dietary phytase supplementation improved the apparent retention of Ca, Na and Cu and ileal phytate P absorption from 32% to 44% across inclusion levels. 6. Bone mineral density (BMD) was improved for both phytases across inclusion levels by, on average, 9% for the tibia and 13% for the femur. 7. Dietary phytase supplementation of the low-P diet improved apparent ileal digestibility of serine, glycine, valine, isoleucine, tyrosine, histidine, lysine and arginine. 8. When the results from the present study were combined with the results from other similar published studies and analysed statistically, factors such as dietary P and Ca concentration, as well as bird breed and age, rather than the type or activity of microbial phytase, had the greatest impact on the extent to which dietary supplementation improved P and Ca retention. 9. More work is required to explain the interrelationships between the multiple factors influencing the efficacy of phytase on the availability of dietary minerals.

  5. Geologic control of mineral composition of stream waters of the eastern slope of the Southern Coast Ranges, California

    USGS Publications Warehouse

    Davis, G.H.

    1961-01-01

    Chemical analyses of waters of streams that drain the semiarid eastern slope of the southern Coast Ranges in California demonstrate that differences in the anion composition, especially in the ratio of bicarbonate to sulfate, are related chiefly to the lithologic character of the rocks exposed in the tributary drainage area. Where more than hall the drainage area of a typical eastern-slope stream is underlain by clastic marine sedimentary rocks of Jurassic and Cretaceous age, bicarbonate generally predominates over sulfate; the ratio of bicarbonate to sullate, both expressed in equivalents per million, in samples of the streams at low-flow stage ranges from 0.8 to 6. Conversely, where more than hall the drainage area is underlain by marine and continental deposits of Tertiary age and continental deposits of Quaternary age, sulfate predominates over bicarbonate, and the ratio of bicarbonate to sulfate in samples taken during the low-flow stage ranges from 0.02 to 0.7. Organic siliceous marine shale of Tertiary age deposited in a reducing environment is probably the primary source of sullate in the region. Secondary deposits of sulfate minerals, chiefly gypsum, which are abundant in the continental deposits of late Tertiary and Quaternary age, also contribute sullate to the stream waters.

  6. Estimating the melting point, entropy of fusion, and enthalpy of ...

    EPA Pesticide Factsheets

    The entropies of fusion, enthalies of fusion, and melting points of organic compounds can be estimated through three models developed using the SPARC (SPARC Performs Automated Reasoning in Chemistry) platform. The entropy of fusion is modeled through a combination of interaction terms and physical descriptors. The enthalpy of fusion is modeled as a function of the entropy of fusion, boiling point, and fexibility of the molecule. The melting point model is the enthlapy of fusion divided by the entropy of fusion. These models were developed in part to improve SPARC's vapor pressure and solubility models. These models have been tested on 904 unique compounds. The entropy model has a RMS of 12.5 J mol-1K-1. The enthalpy model has a RMS of 4.87 kJ mol-1. The melting point model has a RMS of 54.4°C. Published in the journal, SAR and QSAR in Environmental Research

  7. Microbially mediated mineral carbonation

    NASA Astrophysics Data System (ADS)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  8. Antioxidative effects of sulfurous mineral water: protection against lipid and protein oxidation.

    PubMed

    Benedetti, S; Benvenuti, F; Nappi, G; Fortunati, N A; Marino, L; Aureli, T; De Luca, S; Pagliarani, S; Canestrari, F

    2009-01-01

    To investigate the antioxidative properties of sulfurous drinking water after a standard hydropinic treatment (500 ml day(-1) for 2 weeks). Forty apparently healthy adults, 18 men and 22 women, age 41-55 years old. The antioxidant profile and the oxidative condition were evaluated in healthy subjects supplemented for 2 weeks with (study group) or without (controls) sulfurous mineral water both before (T0) and after (T1) treatment. At T1, a significant decrease (P<0.05) in both lipid and protein oxidation products, namely malondialdehyde, carbonyls and AOPP, was found in plasma samples from subjects drinking sulfurous water with respect to controls. Concomitantly, a significant increment (P<0.05) of the total antioxidant capacity of plasma as well as of total plasmatic thiol levels was evidenced. Tocopherols, carotenoids and retinol remained almost unchanged before and after treatment in both groups. The improved body redox status in healthy volunteers undergoing a cycle of hydropinic therapy suggests major benefits from sulfurous water consumption in reducing biomolecule oxidation, possibly furnishing valid protection against oxidative damage commonly associated with aging and age-related degenerative diseases.

  9. Boundary Layer Transition and Trip Effectiveness on an Apollo Capsule in the JAXA High Enthalpy Shock Tunnel (HIEST) Facility

    NASA Technical Reports Server (NTRS)

    Kirk, Lindsay C.; Lillard, Randolph P.; Olejniczak, Joseph; Tanno, Hideyuki

    2015-01-01

    Computational assessments were performed to size boundary layer trips for a scaled Apollo capsule model in the High Enthalpy Shock Tunnel (HIEST) facility at the JAXA Kakuda Space Center in Japan. For stagnation conditions between 2 MJ/kg and 20 MJ/kg and between 10 MPa and 60 MPa, the appropriate trips were determined to be between 0.2 mm and 1.3 mm high, which provided kappa/delta values on the heatshield from 0.15 to 2.25. The tripped configuration consisted of an insert with a series of diamond shaped trips along the heatshield downstream of the stagnation point. Surface heat flux measurements were obtained on a capsule with a 250 mm diameter, 6.4% scale model, and pressure measurements were taken at axial stations along the nozzle walls. At low enthalpy conditions, the computational predictions agree favorably to the test data along the heatshield centerline. However, agreement becomes less favorable as the enthalpy increases conditions. The measured surface heat flux on the heatshield from the HIEST facility was under-predicted by the computations in these cases. Both smooth and tripped configurations were tested for comparison, and a post-test computational analysis showed that kappa/delta values based on the as-measured stagnation conditions ranged between 0.5 and 1.2. Tripped configurations for both 0.6 mm and 0.8 mm trip heights were able to effectively trip the flow to fully turbulent for a range of freestream conditions.

  10. Jatropha curcas leaves analysis, reveals it as mineral source for low sodium diets.

    PubMed

    Méndez, Lucero; Rojas, Janne; Izaguirre, César; Contreras, Billmary; Gómez, Rubén

    2014-12-15

    Jatropha curcas is a perennial herb, belonging to the family Euphorbiaceae, found in countries such as India, Mexico and Venezuela. In the present study, proximate composition and mineral content on the leaves of J. curcas was analysed and compared to spinach (Spinacia oleracea L.) using a ICP-AES. The bromatologic test (dry material) results for ashes, proteins, lipids and carbohydrates revealed 23.4%, 28.0%, 3.2% and 45.4% for J. curcas; whereas for S. oleracea values were 28.9%, 20.8%, 0.5% and 49.9%. Furthermore, minerals found in both species ashes were: calcium, potassium, magnesium, iron and phosphorus, resulting that leaves of J. curcas are composed by three times the iron and calcium amount comparing to spinach; while sodium was absent from the former species. In this study Cu and Zn were found only in spinach, while Pb and As were not detected in any of the studied species. These results indicate that J. curcas leaves might be considered as mineral source suitable for animal and human consumption, especially for people who requires a low sodium diet. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Assessment of CO2-Induced Geochemical Changes in Soil/Mineral-Water Systems

    NASA Astrophysics Data System (ADS)

    Jeong, H. Y.; Choi, H. J.

    2016-12-01

    Although the storage of CO2 in deep geological formations is considered the most promising sequestration path, there is still a risk that it may leak into the atmosphere. To ensure the secure operation of CO2 storage sites, thus, it is necessary to implement CO2 leakage monitoring systems. Furthermore, the leakage may alter geochemical properties of overlying geological units to have adverse environmental consequences. By elucidating geochemical changes due to CO2 leakage, it is possible to develop effective CO2 monitoring techniques and predict the influence of CO2 leakage. A series of batch experiments were conducted to simulate CO2-induced geochemical changes in soil/mineral-water systems. Soil samples, obtained from Eumseong basin in Eumseong-gun, Chungcheongbuk-do, were dried for 6 hours at 60° and then divided into two size fractions: < 106 and 106-212 mm. Minerals including mica/illite, vermiculite, and feldspar were purchased and purified if necessary. Prior to batch experiments, soils and minerals were characterized for surface area, mineralogy, elemental composition, carbon and nitrogen contents, pH buffering capacity, and metal extractability. Batch experiments were initiated by reacting 100% CO2 atmosphere with aqueous suspensions of 120 g soils or 50 g minerals in 3,000 mL of 10 mM CsClO4 at room temperature. In parallel, the batches having the same soil/mineral compositions were run under the ambient air as controls. To prevent microbial activities, all batches were sterilized with 0.03% HCHO. To track geochemical changes, pH and electrical conductivity were monitored. Also, while solutions were regularly sampled and analyzed for trace metals as well as main cations and anions, solid phases were sampled to observe changes in mineralogical compositions. Geochemical changes in both solution and solid phases during the initial 6 month reaction will be presented. Acknowledgement: The "R&D Project on Environmental Management of Geologic CO2 Storage" from

  12. Oxygen isotope fractionation effects in soil water via interaction with cations (Mg, Ca, K, Na) adsorbed to phyllosilicate clay minerals

    NASA Astrophysics Data System (ADS)

    Oerter, Erik; Finstad, Kari; Schaefer, Justin; Goldsmith, Gregory R.; Dawson, Todd; Amundson, Ronald

    2014-07-01

    In isotope-enabled hydrology, soil and vadose zone sediments have been generally considered to be isotopically inert with respect to the water they host. This is inconsistent with knowledge that clay particles possessing an electronegative surface charge and resulting cation exchange capacity (CEC) interact with a wide range of solutes which, in the absence of clays, have been shown to exhibit δ18O isotope effects that vary in relation to the ionic strength of the solutions. To investigate the isotope effects caused by high CEC clays in mineral-water systems, we created a series of monominerallic-water mixtures at gravimetric water contents ranging from 5% to 32%, consisting of pure deionized water of known isotopic composition with homoionic (Mg, Ca, Na, K) montmorillonite. Similar mixtures were also created with quartz to determine the isotope effect of non-, or very minimally-, charged mineral surfaces. The δ18O value of the water in these monominerallic soil analogs was then measured by isotope ratio mass spectrometry (IRMS) after direct headspace CO2 equilibration. Mg- and Ca-exchanged homoionic montmorillonite depleted measured δ18O values up to 1.55‰ relative to pure water at 5% water content, declining to 0.49‰ depletion at 30% water content. K-montmorillonite enriched measured δ18O values up to 0.86‰ at 5% water content, declining to 0.11‰ enrichment at 30% water. Na-montmorillonite produces no measureable isotope effect. The isotope effects observed in these experiments may be present in natural, high-clay soils and sediments. These findings have relevance to the interpretation of results of direct CO2-water equilibration approaches to the measurement of the δ18O value of soil water. The adsorbed cation isotope effect may bear consideration in studies of pedogenic carbonate, plant-soil water use and soil-atmosphere interaction. Finally, the observed isotope effects may prove useful as molecular scale probes of the nature of mineral-water

  13. Dispersive liquid-liquid microextraction based on solidification of floating organic droplet for the determination of triazine and triazoles in mineral water samples.

    PubMed

    Bolzan, Cátia M; Caldas, Sergiane S; Guimarães, Bruno S; Primel, Ednei G

    2016-09-01

    A simple, rapid, and sensitive method for the determination of atrazine, simazine, cyproconazole, tebuconazole, and epoxiconazole in mineral water employing the dispersive liquid-liquid microextraction with solidification of a floating organic drop with determination by liquid chromatography tandem mass spectrometry has been developed. A mixed solution of 250 μL 1-dodecanol and 1250 μL methanol was injected rapidly into 10 mL aqueous solution (pH 7.0) with 2% w/v NaCl. After centrifugation for 5 min at 2000 rpm, the organic solvent droplets floated on the surface of the aqueous solution and the floating solvent solidified. The method limits of detection were between 3.75 and 37.5 ng/L and limits of quantification were between 12.5 and 125 ng/L. The recoveries ranged from 70 to 118% for repeatability and between 76 and 95% for intermediate precision with a relative standard deviation from 2 to 18% for all compounds. Low matrix effect was observed. The proposed method can be successfully applied in routine analysis for determination of pesticide residues in mineral water samples, allowing for monitoring of triazine and triazoles at levels below the regulatory limits set by international and national legislations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. A study of the vaporization enthalpies of some 1-substituted imidazoles and pyrazoles by correlation-gas chromatography.

    PubMed

    Lipkind, Dmitry; Plienrasri, Chatchawat; Chickos, James S

    2010-12-23

    The vaporization enthalpies of 1-methyl-, 1-ethyl-, 1-phenyl-, and 1-benzylimidazole, 1-methyl- and 1-phenylpyrazole, and trans-azobenzene are evaluated by correlation-gas chromatography (C-GC) using a variety of azines and diazines as standards. The vaporization enthalpies obtained by C-GC when compared to literature values are approximately 14 kJ·mol(-1) smaller for the imidazoles and 6 kJ·mol(-1) smaller for the pyrazoles. The literature vaporization enthalpies of 1-methylpyrrole and 1-methylindole, two closely related compounds with one less nitrogen, are reproduced by C-GC. These results suggest that the magnitude of the intermolecular interactions present in 1-substituted imidazoles and pyrazoles are significantly larger than the those present in the reference compounds and greater than or equal in magnitude to the enhanced intermolecular interactions observed previously in aromatic 1,2-diazines. The vaporization enthalpy and vapor pressure of a trans-1,2-diazine, trans-azobenzene, measured by C-GC using similar standards reproduced the literature values within experimental error.

  15. Water of Hydration Dynamics in Minerals Gypsum and Bassanite: Ultrafast 2D IR Spectroscopy of Rocks.

    PubMed

    Yan, Chang; Nishida, Jun; Yuan, Rongfeng; Fayer, Michael D

    2016-08-03

    Water of hydration plays an important role in minerals, determining their crystal structures and physical properties. Here ultrafast nonlinear infrared (IR) techniques, two-dimensional infrared (2D IR) and polarization selective pump-probe (PSPP) spectroscopies, were used to measure the dynamics and disorder of water of hydration in two minerals, gypsum (CaSO4·2H2O) and bassanite (CaSO4·0.5H2O). 2D IR spectra revealed that water arrangement in freshly precipitated gypsum contained a small amount of inhomogeneity. Following annealing at 348 K, water molecules became highly ordered; the 2D IR spectrum became homogeneously broadened (motional narrowed). PSPP measurements observed only inertial orientational relaxation. In contrast, water in bassanite's tubular channels is dynamically disordered. 2D IR spectra showed a significant amount of inhomogeneous broadening caused by a range of water configurations. At 298 K, water dynamics cause spectral diffusion that sampled a portion of the inhomogeneous line width on the time scale of ∼30 ps, while the rest of inhomogeneity is static on the time scale of the measurements. At higher temperature, the dynamics become faster. Spectral diffusion accelerates, and a portion of the lower temperature spectral diffusion became motionally narrowed. At sufficiently high temperature, all of the dynamics that produced spectral diffusion at lower temperatures became motionally narrowed, and only homogeneous broadening and static inhomogeneity were observed. Water angular motions in bassanite exhibit temperature-dependent diffusive orientational relaxation in a restricted cone of angles. The experiments were made possible by eliminating the vast amount of scattered light produced by the granulated powder samples using phase cycling methods.

  16. A general strategy for the experimental study of the thermochemistry of protic ionic liquids: enthalpy of formation and vaporisation of 1-methylimidazolium ethanoate.

    PubMed

    Vitorino, Joana; Bernardes, Carlos E S; Minas da Piedade, Manuel E

    2012-04-07

    A general strategy to determine enthalpies of formation of protic ionic liquids, based solely on enthalpy of solution measurements, was conceived and tested for 1-methylimidazolium ethanoate, leading to Δ(f)H°(m){[Hmim][O(2)CCH(3)], 1} = -(425.7 ± 1.2) kJ mol(-1). This result in conjunction with the enthalpy of formation of gaseous 1-methylimidazole (mim) proposed in this work, Δ(f)H°(m)(mim, g) = 126.5 ± 1.1 kJ mol(-1), and Δ(f)H°(m)(CH(3)COOH, g) taken from the literature, allowed the calculation of the enthalpy of the vaporisation process [Hmim][O(2)CCH(3)](l) → mim(g) + CH(3)COOH(g) as Δ(vap)H°(m){[Hmim][O(2)CCH(3)]} = 119.4 ± 3.0 kJ mol(-1). The agreement between this value and Δ(vap)H°(m){[Hmim][O(2)CCH(3)]} = 117.3 ± 0.5 kJ mol(-1), obtained for the direct vaporisation of [Hmim][O(2)CCH(3)], by Calvet-drop microcalorimetry, gives a good indication that, as previously suggested by Fourier transform ion cyclotron resonance mass spectrometry, Raman spectroscopy, and GC-MS experiments, the vaporisation of [Hmim][O(2)CCH(3)] essentially involves a proton transfer mechanism with formation of the two volatile neutral precursor molecules (mim and CH(3)COOH). Although being a low ionicity protic ionic liquid, [Hmim][O(2)CCH(3)] was chosen to validate the methodology proposed here, since its vaporisation mechanism has been unequivocally demonstrated by different methods and for different pressure ranges.

  17. [Therapeutic effect of the association between pulmonary ventilation and aerosol--inhalation with sulphureous mineral water in the chronic bronchopneumopathies].

    PubMed

    Lopalco, M; Proia, A R; Fraioli, A; Serio, A; Cammarella, I; Petraccia, L; Grassi, M

    2004-04-01

    Our research evaluates the efficacy of the inalation therapy by mineral sulphureous water in patients suffering from cronic bronchopneumopathy. From August to October 2002, two groups of patients, randomly selected, suffering from cronic bronchopneumonopathy, were studied at spa center "Pompeo" in Ferentino (FR). Every patient was treated daily during a cycle of twelve days. The first group was treated by pneumonic mechanical ventilation associated to sulphureous water aerosolinalation, the second by mechanical pulmonary ventilation associated to sulphureous water aerosol-inalation medicated with flunisolide. Every patient carried out spirometry, before and after treatment, and the measurement of FEV1 was considered a good parameter to evaluate the respiratory function. All patients reported an improvement in symptoms as dyspnea and cough. Results obtained show a significant functional improvement of respiratory function in both groups, evaluated by FEV1. Equal efficacy treating the patients by medicated and not medicated treatments stress the therapeutic role of mineral sulphureous waters in chronic bronchopneumopathies. Our research points out the usefullness of pneumonic ventilation associated with sulphureous water aerosol-inalation in patients suffering from chronic bronchopneumopathies.

  18. Low-temperature hydrothermal synthesis of ZnO nanorods: Effects of zinc salt concentration, various solvents and alkaline mineralizers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Edalati, Khatereh, E-mail: kh_ed834@stu.um.ac.ir; Shakiba, Atefeh; Vahdati-Khaki, Jalil

    2016-02-15

    Highlights: • We synthesized ZnO nanorods by a simple hydrothermal process at 60 °C. • Effects of zinc salt concentration, solvent and alkaline mineralizer was studied. • Increasing concentration of zinc salt changed ZnO nucleation system. • NaOH yielded better results in the production of nanorods in both solvents. • Methanol performed better in the formation of nanorods using the two mineralizers. - Abstract: ZnO has been produced using various methods in the solid, gaseous, and liquid states, and the hydrothermal synthesis at low temperatures has been shown to be an environmentally-friendly one. The current work utilizes a low reactionmore » temperature (60 °C) for the simple hydrothermal synthesis of ZnO nanorod morphologies. Furthermore, the effects of zinc salt concentration, solvent type and alkaline mineralizer type on ZnO nanorods synthesis at a low reaction temperature by hydrothermal processing was studied. Obtained samples were analyzed using X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Increasing the concentration of the starting zinc salt from 0.02 to 0.2 M changed ZnO nucleation system from the homogeneous to the heterogeneous state. The XRD results confirmed the production hexagonal ZnO nanostructures of with a crystallite size of 40.4 nm. Varying the experimental parameters (mineralizer and solvent) yielded ZnO nanorods with diameters ranging from 90–250 nm and lengths of 1–2 μm.« less

  19. Iron alteration minerals in the visible and near-infrared spectra of low-albedo asteroids

    NASA Technical Reports Server (NTRS)

    Vilas, Faith; Jarvis, Kandy S.; Gaffey, Michael J.

    1994-01-01

    Absorption features centered near 0.60-0.65 and 0.80-0.90 micrometers have been identified in the spectra of five low-albedo main-belt and outer-belt asteroids. These absorption features are attributed respectively to the (6)A(sub 1) goes to (4)T(sub 2)(G) and (6)A(sub 1) goes to (4)T(sub 1)(G) charge transfer transitions in minerals such as goethite, hematite, and jarosite that are products of the aqueous alteration of anhydrous silicates. A shoulder near 0.63 micrometers has also been identified in the absorption feature centered near 0.7 micrometers attributed to oxidized iron in phyllosilicates found predominantly in C- and G-class asteroids reflectance spectra. The coexistence of iron oxides with phyllosilicates in asteroids believed to have undergone aqueous alteration would be expected based upon analogy with terrestrial aqueous alteration and the observed mineralogy of carbonaceous chondrites. The number of low-albedo asteroids having only iron alteration absorption features compared to the number of low-albedo asteroids having spectral characteristics indicative of phyllosilicates is small. Either the conditions under which these asteroids formed are rare, or the iron alteration minerals could be formed in the interiors of objects where phyllosilicates dominate the surface mineralogy.

  20. Role of Phosphorus Minerals in the Origin of Life on Earth

    NASA Astrophysics Data System (ADS)

    Gull, M.; Pasek, M. A.

    2013-12-01

    In the origin of life, phosphorus (P) plays a vital role as it is a key biologic element (1). However, a big question still remains as to how P was incorporated into the first biomolecules as the availability of dissolved P in water is low. Orthophosphate minerals such as apatite, whitelockite and monetite are the major carriers of phosphate on Earth, but these are poorly soluble in water and are inert. The recent discovery of phosphite in Archean rocks (2) suggests that it is likely that some other source of P was present on the early Earth which could very well mix with Hadean Ocean to generate biomolecules. The meteoritic mineral schreibersite (SC thereafter) may have provided reduced P that would corrode into water and generate reactive inorganic P. In this study we present the significance of some important P minerals including apatite, whitelockite, monazite, struvite, monetite and meteoritic mineral SC (or its synthetic analogue Fe3P). Two major aspects of these P minerals were studied; first the release of P into water and second whether phosphorylation of organic compound (glycerol) could be carried out. It was seen all the phosphate minerals such as apatite, whitelockite, monazite and monetite when heated (65-75oC for 8-10 days) with an aqueous solution of 0.5 M glycerol gave no prominent phosphorylated products (P31NMR & mass spectrometry) and released very little amount of phosphate into water and remained inert. Struvite on heating with glycerol gave around 8-10 % of glycerol monophosphates along with phosphate release in the water. When SC (or Fe3P) was heated in an aqueous solution of glycerol it not only yielded 3-6 % glycerol monophosphates but also some glycerol-di-phosphate along with rich species of inorganic P compounds. SC from the meteorite Seymchan also demonstrated phosphorylation of glycerol. Since the prebiotic role of struvite mineral as a prebiotic P mineral is not clearly known (3), this suggests SC was a potential prebiotic P source

  1. Mineral Tells Tale of Watery Past

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This spectrum, taken by the Mars Exploration Rover Opportunity's Moessbauer spectrometer, shows the presence of an iron-bearing mineral called jarosite in the collection of rocks dubbed 'El Capitan.' 'El Capitan' is located within the rock outcrop that lines the inner edge of the small crater where Opportunity landed. The pair of yellow peaks specifically indicates a jarosite phase, which contains water in the form of hydroxyl as a part of its structure. These data suggest water-driven processes exist on Mars. Three other phases are also identified in this spectrum: a magnetic phase (blue), attributed to an iron-oxide mineral; a silicate phase (green), indicative of minerals containing double-ionized iron (Fe 2+); and a third phase (red) of minerals with triple-ionized iron (Fe 3+).

  2. Substituent and ring effects on enthalpies of formation: 2-methyl- and 2-ethylbenzimidazoles versus benzene- and imidazole-derivatives

    NASA Astrophysics Data System (ADS)

    Jiménez, Pilar; Roux, María Victoria; Dávalos, Juan Z.; Temprado, Manuel; Ribeiro da Silva, Manuel A. V.; Ribeiro da Silva, Maria Das Dores M. C.; Amaral, Luísa M. P. F.; Cabildo, Pilar; Claramunt, Rosa M.; Mó, Otilia; Yáñez, Manuel; Elguero, José

    The enthalpies of combustion, heat capacities, enthalpies of sublimation and enthalpies of formation of 2-methylbenzimidazole (2MeBIM) and 2-ethylbenzimidazole (2EtBIM) are reported and the results compared with those of benzimidazole itself (BIM). Theoretical estimates of the enthalpies of formation were obtained through the use of atom equivalent schemes. The necessary energies were obtained in single-point calculations at the B3LYP/6-311+G(d,p) on B3LYP/6-31G* optimized geometries. The comparison of experimental and calculated values of benzenes, imidazoles and benzimidazoles bearing H (unsubstituted), methyl and ethyl groups shows remarkable homogeneity. The energetic group contribution transferability is not followed, but either using it or adding an empirical interaction term, it is possible to generate an enormous collection of reasonably accurate data for different substituted heterocycles (pyrazole-derivatives, pyridine-derivatives, etc.) from the large amount of values available for substituted benzenes and those of the parent (pyrazole, pyridine) heterocycles.

  3. Carbonation of Clay Minerals Exposed to scCO2/Water at 200 degrees and 250 degrees C

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sugama, T.; Ecker, L.; Gill, S.

    2010-11-01

    To clarify the mechanisms of carbonation of clay minerals, such as bentonite, kaolinite, and soft clay, we exposed them to supercritical carbon dioxide (scCO2)/water at temperatures of 200 and 250 C and pressures of 1500 and 2000 psi for 72- and 107-hours. Bentonite, comprising three crystalline phases, montmorillonite (MMT), anorthoclase-type albite, and quartz was susceptible to reactions with ionic carbonic acid yielded by the interactions between scCO2 and water, particularly MMT and anorthoclase-type albite phases. For MMT, the cation-exchangeable ions, such as Na+ and Ca2+, present in its basal interplanar space, were replaced by proton, H+, from ionic carbonic acid;more » thereafter, the cations leaching from MMT directly reacted with CO32- as a counter ion of H+ to form carbonate compounds. Such in-situ carbonation process in basal space caused the shrinkage and breakage of the spacing structure within MMT. In contrast, the wet carbonation of anorthoclase-type albite, categorized as rock minerals, entailed the formation of three amorphous by-products, such as carbonates, kaolinite-like compounds, and silicon dioxide. Together, these two different carbonations caused the disintegration and corruption of bentonite. Kaolinite clay containing the amorphous carbonates and silicon dioxide was inert to wet carbonation. We noted only a gain in weight due to its water uptake, suggesting that kaolinite-like by-products generated by the wet carbonation of rock minerals might remain unchanged even during extended exposure. Soft clay consisting of two crystalline phases, dolomite and silicon dioxide, also was unaltered by wet carbonation, despite the uptake of water.« less

  4. Enthalpy of Formation for Cu–Zn–Sn–S (CZTS) Calculated from Surface Binding Energies Experimentally Measured by Ion Sputtering

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Baryshev, Sergey V.; Thimsen, Elijah

    2015-04-14

    Herein, we report an analytical procedure to calculate the enthalpy of formation for thin film multinary compounds from sputtering rates measured during ion bombardment. The method is based on Sigmunds sputtering theory and the BornHaber cycle. Using this procedure, an enthalpy of formation for a CZTS film of the composition Cu1.9Zn1.5Sn0.8S4 was measured as -930 +/- 98 kJ mol1. This value is much more negative than the sum of the enthalpies of formation for the constituent binary compounds, meaning the multinary formation reaction is predicted to be exothermic. The measured enthalpy of formation was used to estimate the temperature dependencemore » of the Gibbs free energy of reaction, which appears consistent with many experimental reports in the CZTS processing literature.« less

  5. Low bone mineral density and fragility fractures in permanent vegetative state patients.

    PubMed

    Oppl, Bastian; Michitsch, Gabriele; Misof, Barbara; Kudlacek, Stefan; Donis, Johann; Klaushofer, Klaus; Zwerina, Jochen; Zwettler, Elisabeth

    2014-01-01

    Disuse of the musculoskeletal system causes bone loss. Whether patients in vegetative state, a dramatic example of immobilization after severe brain injury, suffer from bone loss and fractures is currently unknown. Serum markers of bone turnover, bone mineral density (BMD) measurements, and clinical data were cross-sectionally analyzed in 30 consecutive vegetative state patients of a dedicated apallic care unit between 2003 and 2007 and compared with age- and sex-matched healthy individuals. Vegetative state patients showed low calcium levels and vitamin D deficiency compared with healthy controls. Serum bone turnover markers revealed high turnover as evidenced by markedly elevated carboxy-terminal telopeptide of type I collagen (β-crosslaps) and increased levels of alkaline phosphatase. BMD measured by dual-energy X-ray absorptiometry (DXA) scanning showed strongly decreased T- and Z-scores for hip and spine. Over a period of 5 years, 8 fragility fractures occurred at peripheral sites in 6 of 30 patients (n = 3 femur, n = 2 tibia, n = 2 fibula, n = 1 humerus). In conclusion, high bone turnover and low BMD is highly prevalent in vegetative state patients, translating into a clinically relevant problem as shown by fragility fractures in 20% of patients over a time period of 5 years. . © 2014 American Society for Bone and Mineral Research.

  6. [Hormonal and metabolic effects of drinking mineral water and phytoaeronisation in experimental prostatitis].

    PubMed

    Polushina, N D; Agaev, A A; Shchelkunov, A V; Eseneev, S M

    2004-01-01

    Prostatitis modelled in 53 Wistar male rats (300-350 body mass) 7 days after its induction was treated with mineral water "Essentuki N 17" (MW) which was taken in a dose 1.5-2 ml per 100 g body mass for 23-24 days. In addition, some animals received phytoaeroionisation (PAI) with solution of essential oils of mint, sage and lavender. Prostatitis is associated with disorders in prostatic tissue, levels of sex hormones (testosterone, prolactin, FSH, LH), a rise in total cholesterol, glucose. Watering of animals with MW and PAI raised blood insulin, hydrocortisone and testosterone, normalized blood glucose and cholesterol. There was a correlation between blood levels of hydrocortisone and testosterone.

  7. Measuring Enthalpy of Sublimation of Volatiles by Means of Piezoelectric Crystal Microbalances

    NASA Astrophysics Data System (ADS)

    Dirri, Fabrizio; Palomba, Ernesto; Longobardo, Andrea; Zampetti, Emiliano

    2017-12-01

    Piezoelectric Crystal Microbalances (PCM's) are widely used to study the chemical processes involving volatile compounds in any environment, such as condensation process. Since PCM's are miniaturized sensor, they are very suitable for planetary in situ missions, where can be used to detect and to measure the mass amount of astrobiologically significant compounds, such as water and organics. This work focuses on the realization and testing of a new experimental setup, able to characterize volatiles which can be found in a planetary environment. In particular the enthalpy of sublimation of some dicarboxylic acids has been measured. The importance of dicarboxylic acids in planetology and astrobiology is due to the fact that they have been detected in carbonaceous chondritic material (e.g. Murchinson), among the most pristine material present in our Solar System. In this work, a sample of acid was heated in an effusion cell up to its sublimation. For a set of temperatures (from 30 °C to 75 °C), the deposition rate on the PCM surface has been measured. From these measurements, it has been possible to infer the enthalpy of sublimation of Adipic acid, i.e. ΔH = 141.6 ± 0.8 kJ/mol and Succinic acid, i.e. ΔH = 113.3 ± 1.3 kJ/mol. This technique has so demonstrated to be a good choice to recognise a single compound or a mixture (with an analysis upstream) even if some improvements concerning the thermal stabilization of the system will be implemented in order to enhance the results' accuracy. The experiment has been performed in support of the VISTA (Volatile In Situ Thermogravimetry Analyzer) project, which is included in the scientific payload of the ESA MarcoPolo-R mission study.

  8. Determinants of low bone mineral density in children with epilepsy.

    PubMed

    Fong, Choong Yi; Kong, Ann Nie; Noordin, Mazidah; Poh, Bee Koon; Ong, Lai Choo; Ng, Ching Ching

    2018-01-01

    Children with epilepsy on long-term antiepileptic drugs (AEDs) are at risk of low bone mineral density (BMD). The aims of our study were to evaluate the prevalence and determinants of low BMD among Malaysian children with epilepsy. Cross-sectional study of ambulant children with epilepsy on long-term AEDs for >1 year seen in a tertiary hospital in Malaysia from 2014 to 2015. Detailed assessment of anthropometric measurements; environmental lifestyle risk factors; serum vitamin D, calcium and parathyroid hormone levels; genotyping of single nucleotide polymorphisms of genes in vitamin D and calcium metabolism; and lumbar spine BMD were obtained. Low BMD was defined as BMD Z-score ≤ -2.0 SD. Eighty-seven children with mean age of 11.9 years (56 males) participated in the study. The prevalence of low lumbar BMD was 21.8% (19 patients). Multivariate logistic regression analysis identified polytherapy >2 AEDs (OR: 7.86; 95% CI 1.03-59.96), small frame size with wrist breadth of <15th centile (OR 14.73; 95% CI 2.21-98.40), and body mass index Z-score < -2.0 (OR 8.73, 95% CI 1.17-65.19) as significant risk factors for low BMD. One-fifth of Malaysian children with epilepsy on long-term AEDs had low BMD. Targeted BMD should be performed for those who are on >2 AEDs, underweight or with small frame size as they are at higher risk of having low BMD. Copyright © 2017 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  9. A proposal to investigate higher enthalpy geothermal systems in the USA

    NASA Astrophysics Data System (ADS)

    Elders, W. A.

    2013-12-01

    After more than 50 years of development only ~3,400 MWe of electric power is currently being produced from geothermal resources in the USA. That is only about 0.33% of the country's total installed electrical capacity. In spite of the large demonstrated potential of geothermal resources, only ~2,500 MWe of new geothermal electrical capacity are under development, and the growth rate of this environmentally benign energy resource is overshadowed by the rapid increase in the installed capacity of wind and solar energy. Most of the new geothermal developments in the USA involve relatively small, moderate-temperature, geothermal systems. In contrast, development of higher enthalpy geothermal systems for power production has obvious advantages; specifically higher temperatures yield higher power outputs per well so that fewer wells are needed, leading to smaller environmental footprints for a given size of power plant. Disadvantages include that the fact that locations of suitable geothermal systems are restricted to young volcanic terrains, production of very high enthalpy fluids usually requires drilling deeper wells and may require enhanced geothermal (EGS) technology, and drilling deep into hot hostile environments is technologically challenging. However the potential for very favorable economic returns suggests that the USA should begin developing such a program. One approach to mitigating the cost issue is to form a consortium of industry, government and academia to share the costs and broaden the scope an investigation. An excellent example of such a collaboration is the Iceland Deep Drilling Project (IDDP) which is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs. This industry-government consortium planned to drill a deep well in the volcanic caldera of Krafla in NE Iceland. However drilling had to be terminated at 2.1 km depth when 900°C rhyolite magma flowed into the well. The resultant well was highly

  10. Enthalpy measurement of coal-derived liquids. Final report, April 1981-September 1983. [517 to 10342 kPa; 340 to 664 K

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kidnay, A.J.; Yesavage, V.F.

    This report summarizes the results of experimental measurements of enthalpies for quinoline using a freon boil-off flow calorimeter, and an investigation of the applicability of cubic equations of state to correlating the enthalpy of coal-liquids. In Part A the compound quinoline is discussed. Process flow in the flow calorimeter, operational problems, and equipment modifications are described. Procedural modifications, including a new sample purification procedure, are described. Part B discusses the correlational effort. This includes a discussion of past correlational work and the difficulties associated with a general correlation for coal liquid enthalpy. In addition experimental data and computer generated predictionsmore » are presented. Three equations of state were used to predict vapor pressures and enthalpies for ten pure component systems previously studied in the lab. In general, the results were encouraging. All three equations were found to be effective in predicting both enthalpies and vapor pressures. In addition, the equations worked well when fit to mixture enthalpies. The Modified SRK equation was found to be superior to the other equations and modeled all properties for both associating and nonassociating systems well. The Modified SRK equation did have a drawback in that it was not readily generalized since it required two parameters which must be fit to data for best results. In sum, it was shown that a four parameter equation of state could be used successfully to correlate the enthalpy of coal-liquid model compounds.« less

  11. Mineral deposit densities for estimating mineral resources

    USGS Publications Warehouse

    Singer, Donald A.

    2008-01-01

    Estimates of numbers of mineral deposits are fundamental to assessing undiscovered mineral resources. Just as frequencies of grades and tonnages of well-explored deposits can be used to represent the grades and tonnages of undiscovered deposits, the density of deposits (deposits/area) in well-explored control areas can serve to represent the number of deposits. Empirical evidence presented here indicates that the processes affecting the number and quantity of resources in geological settings are very general across many types of mineral deposits. For podiform chromite, porphyry copper, and volcanogenic massive sulfide deposit types, the size of tract that geologically could contain the deposits is an excellent predictor of the total number of deposits. The number of mineral deposits is also proportional to the type’s size. The total amount of mineralized rock is also proportional to size of the permissive area and the median deposit type’s size. Regressions using these variables provide a means to estimate the density of deposits and the total amount of mineralization. These powerful estimators are based on analysis of ten different types of mineral deposits (Climax Mo, Cuban Mn, Cyprus massive sulfide, Franciscan Mn, kuroko massive sulfide, low-sulfide quartz-Au vein, placer Au, podiform Cr, porphyry Cu, and W vein) from 108 permissive control tracts around the world therefore generalizing across deposit types. Despite the diverse and complex geological settings of deposit types studied here, the relationships observed indicate universal controls on the accumulation and preservation of mineral resources that operate across all scales. The strength of the relationships (R 2=0.91 for density and 0.95 for mineralized rock) argues for their broad use. Deposit densities can now be used to provide a guideline for expert judgment or used directly for estimating the number of most kinds of mineral deposits.

  12. Carbonate mineral solubility at low temperatures in the Na-K-Mg-Ca-H-Cl-SO 4-OH-HCO 3-CO 3-CO 2-H 2O system

    NASA Astrophysics Data System (ADS)

    Marion, Giles M.

    2001-06-01

    Carbonate minerals have played an important role in the geochemical evolution of Earth, and may have also played an important role in the geochemical evolution of Mars and Europa. Several models have been published in recent years that describe chloride and sulfate mineral solubilities in concentrated brines using the Pitzer equations. Few of these models are parameterized for subzero temperatures, and those that are do not include carbonate chemistry. The objectives of this work are to estimate Pitzer-equation bicarbonate-carbonate parameters and carbonate mineral solubility products and to incorporate them into the FREZCHEM model to predict carbonate mineral solubilities in the Na-K-Mg-Ca-H-Cl-SO 4-OH-HCO 3-CO 3-CO 2-H 2O system at low temperatures (≤25°C) with a special focus on subzero temperatures. Most of the Pitzer-equation parameters and equilibrium constants are taken from the literature and extrapolated into the subzero temperature range. Solubility products for 14 sodium, potassium, magnesium, and calcium bicarbonate and carbonate minerals are included in the model. Most of the experimental data are at temperatures ≥ -8°C; only for the NaHCO 3-NaCl-H 2O and Na 2CO 3-NaCl-H 2O systems are there bicarbonate and carbonate data to temperatures as low as -21.6°C. In general, the fit of the model to the experimental data is good. For example, calculated eutectic temperatures and compositions for NaHCO 3, Na 2CO 3, and their mixtures with NaCl and Na 2SO 4 salts are in good agreement with experimental data to temperatures as low as -21.6°C. Application of the model to eight saline, alkaline carbonate waters give predicted pHs ranging from 9.2 to 10.2, in comparison with measured pHs that range from 8.7 to 10.2. The model suggests that the CaCO 3 mineral that precipitates during seawater freezing is probably calcite and not ikaite. The model demonstrates that a proposed salt assemblage for the icy surface of Europa consisting of highly hydrated MgSO 4

  13. Enthalpies of formation of U-, Th-, Ce-brannerite: implications for plutonium immobilization

    NASA Astrophysics Data System (ADS)

    Helean, K. B.; Navrotsky, A.; Lumpkin, G. R.; Colella, M.; Lian, J.; Ewing, R. C.; Ebbinghaus, B.; Catalano, J. G.

    2003-08-01

    Brannerite, ideally MTi 2O 6, (M=actinides, lanthanides and Ca) occurs in titanate-based ceramics proposed for the immobilization of plutonium. Standard enthalpies of formation, Δ H0f at 298 K, for three brannerite compositions (kJ/mol): CeTi 2O 6 (-2948.8 ± 4.3), U 0.97Ti 2.03O 6 (-2977.9 ± 3.5) and ThTi 2O 6 (-3096.5 ± 4.3) were determined by high temperature oxide melt drop solution calorimetry at 975 K using 3Na 2O · 4MoO 3 solvent. The enthalpies of formation were also calculated from an oxide phase assemblage (Δ H0f-ox at 298 K): MO 2 + 2TiO 2=MTi 2O 6. Only UTi 2O 6 is energetically stable with respect to an oxide assemblage: U 0.97Ti 2.03O 6 (Δ H0f-ox=-7.7±2.8 kJ/mol). Both CeTi 2O 6 and ThTi 2O 6 are higher in enthalpy with respect to their oxide assemblages with (Δ H0f-ox=+29.4±3.6 kJ/mol) and (Δ H0f-ox=+19.4±1.6 kJ/mol) respectively. Thus, Ce- and Th-brannerite are entropy stabilized and are thermodynamically stable only at high temperature.

  14. Surface interactions between silica particles and water and organic solvents

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Douillard, J.M.; Elwafir, M.; Partyka, S.

    1994-04-01

    A silica sample has been studied by vapor adsorption and by microcalorimetric methods. The combination of these two methods in the case of water allows one to calculate all the thermodynamic terms related to the adhesion on this silica. Adhesion between silica and miscellaneous solvents has been studied by immersion microcalorimetry. The silica is slightly hydrophobic, but the enthalpy of immersion into water is the most energetic one of all the solvents studied. It appears a clear graduation of the enthalpies of immersion due to the presence of delocalized electrons in the studied solvents.

  15. Enthalpy Distributions of Arc Jet Flow Based on Measured Laser Induced Fluorescence, Heat Flux and Stagnation Pressure Distributions

    NASA Technical Reports Server (NTRS)

    Suess, Leonard E.; Milhoan, James D.; Oelke, Lance; Godfrey, Dennis; Larin, Maksim Y.; Scott, Carl D.; Grinstead, Jay H.; DelPapa, Steven

    2011-01-01

    The centerline total enthalpy of arc jet flow is determined using laser induced fluorescence of oxygen and nitrogen atoms. Each component of the energy, kinetic, thermal, and chemical can be determined from LIF measurements. Additionally, enthalpy distributions are inferred from heat flux and pressure probe distribution measurements using an engineering formula. Average enthalpies are determined by integration over the radius of the jet flow, assuming constant mass flux and a mass flux distribution estimated from computational fluid dynamics calculations at similar arc jet conditions. The trends show favorable agreement, but there is an uncertainty that relates to the multiple individual measurements and assumptions inherent in LIF measurements.

  16. Fe-Impregnated Mineral Colloids for Peroxide Activation: Effects of Mineral Substrate and Fe Precursor.

    PubMed

    Li, Yue; Machala, Libor; Yan, Weile

    2016-02-02

    Heterogeneous iron species at the mineral/water interface are important catalysts for the generation of reactive oxygen species at circumneutral pH. One significant pathway leading to the formation of such species arises from deposition of dissolved iron onto mineral colloids due to changes in redox conditions. This study investigates the catalytic properties of Fe impregnated on silica, alumina, and titania nanoparticles (as prototypical mineral colloids). Fe impregnation was carried out by immersing the mineral nanoparticles in dilute Fe(II) or Fe(III) solutions at pH 6 and 3, respectively, in an aerobic environment. The uptake of iron per unit surface area follows the order of nTiO2 > nAl2O3 > nSiO2 for both types of Fe precursors. Impregnation of mineral particles in Fe(II) solutions results in predominantly Fe(III) species due to efficient surface-mediated oxidation. The catalytic activity of the impregnated solids to produce hydroxyl radical (·OH) from H2O2 decomposition was evaluated using benzoic acid as a probe compound under dark conditions. Invariably, the rates of benzoic acid oxidation with different Fe-laden particles increase with the surface density of Fe until a critical density above which the catalytic activity approaches a plateau, suggesting active Fe species are formed predominantly at low surface loadings. The critical surface density of Fe varies with the mineral substrate as well as the aqueous Fe precursor. Fe impregnated on TiO2 exhibits markedly higher activity than its Al2O3 and SiO2 counterparts. The speciation of interfacial Fe is analyzed with diffuse reflectance UV-vis analysis and interpretation of the data in the context of benzoic oxidation rates suggests that the surface activity of the solids for ·OH generation correlates strongly with the isolated (i.e., mononuclear) Fe species. Therefore, iron dispersed on mineral colloids is a significant form of reactive iron surfaces in the aquatic environment.

  17. Solid-State Characterization and Relative Formation Enthalpies To Evaluate Stability of Cocrystals of an Antidiabetic Drug.

    PubMed

    Duggirala, Naga Kiran; Frericks Schmidt, Heather L; Lei, Zhaohui; Zaworotko, Michael J; Krzyzaniak, Joseph F; Arora, Kapildev K

    2018-05-07

    The current study integrates formation enthalpy and traditional slurry experiments to quickly assess the physical stability of cocrystal drug substance candidates for their potential to support drug development. Cocrystals of an antidiabetic drug (GKA) with nicotinamide (NMA), vanillic acid (VLA), and ethyl vanillin (EVL) were prepared and characterized by powder X-ray diffractometry (PXRD), spectroscopic, and thermal techniques. The formation enthalpies of the cocrystals, and their physical mixtures (GKA + coformer) were measured by the differential scanning calorimetry (DSC) method reported by Zhang et al. [ Cryst. Growth Des. 2012 , 12 ( 8 ), 4090 - 4097 ]. The experimentally measured differences in the relative formation enthalpies obtained by integrating the heat flow of each cocrystal against the respective physical mixture were correlated to the physical stability of the cocrystals in the solid state. The relative formation enthalpies of all of the cocrystals studied suggest that the cocrystals are not physically stable at room temperature versus their physical mixtures. To further address relative stability, the cocrystals were slurried in 30% v/v aqueous ethanol, and it was observed that all of the cocrystals revert to GKA within 48 h at room temperature. The slurry experiments are consistent with the relative instability of the cocrystals with respect to their physical mixtures suggested by the DSC results.

  18. Free Energy, Enthalpy and Entropy from Implicit Solvent End-Point Simulations.

    PubMed

    Fogolari, Federico; Corazza, Alessandra; Esposito, Gennaro

    2018-01-01

    Free energy is the key quantity to describe the thermodynamics of biological systems. In this perspective we consider the calculation of free energy, enthalpy and entropy from end-point molecular dynamics simulations. Since the enthalpy may be calculated as the ensemble average over equilibrated simulation snapshots the difficulties related to free energy calculation are ultimately related to the calculation of the entropy of the system and in particular of the solvent entropy. In the last two decades implicit solvent models have been used to circumvent the problem and to take into account solvent entropy implicitly in the solvation terms. More recently outstanding advancement in both implicit solvent models and in entropy calculations are making the goal of free energy estimation from end-point simulations more feasible than ever before. We review briefly the basic theory and discuss the advancements in light of practical applications.

  19. Low-rank coal oil agglomeration

    DOEpatents

    Knudson, Curtis L.; Timpe, Ronald C.

    1991-01-01

    A low-rank coal oil agglomeration process. High mineral content, a high ash content subbituminous coals are effectively agglomerated with a bridging oil which is partially water soluble and capable of entering the pore structure, and usually coal derived.

  20. Modification of os calcis bone mineral profiles during bedrest

    NASA Technical Reports Server (NTRS)

    Vogel, J. M.

    1977-01-01

    The mineral content of the left central os calcis was determined using the photon absorptiometric technique modified for the space missions to permit area scanning, and was compared with total body calcium balance changes. The instrument consists of a rectilinear scanner that is programmed by a specially designed control module to move a low energy X-ray emitting radionuclide placed in opposition to a detector to scan the foot which is places between them. The foot is placed in a plexiglas box filled with water to provide tissue equivalence and to compensate for irregularities in thickness of tissue cover that surrounds the bone. The mineral content is obtained from basic attenuation equation.

  1. Thermodynamics of Surfactants, Block Copolymers and Their Mixtures in Water: The Role of the Isothermal Calorimetry

    PubMed Central

    De Lisi, Rosario; Milioto, Stefania; Muratore, Nicola

    2009-01-01

    The thermodynamics of conventional surfactants, block copolymers and their mixtures in water was described to the light of the enthalpy function. The two methodologies, i.e. the van’t Hoff approach and the isothermal calorimetry, used to determine the enthalpy of micellization of pure surfactants and block copolymers were described. The van’t Hoff method was critically discussed. The aqueous copolymer+surfactant mixtures were analyzed by means of the isothermal titration calorimetry and the enthalpy of transfer of the copolymer from the water to the aqueous surfactant solutions. Thermodynamic models were presented to show the procedure to extract straightforward molecular insights from the bulk properties. PMID:19742173

  2. RT-PCR standardization and bone mineralization after low-level laser therapy on adult osteoblast cells

    NASA Astrophysics Data System (ADS)

    do Bomfim, Fernando R. C.; Sella, Valéria R. G.; Zanaga, Jéssica Q.; Pereira, Nayara S.; Nouailhetas, Viviane L. A.; Plapler, Hélio

    2014-03-01

    Purpose: Osteoblasts are capable to produce different compounds directly connected to bone mineralization process. This study aims to standardize the reverse transcriptase polymerase chain reaction (RT-PCR) for adult osteoblasts to observe the effect of low level laser therapy on bone mineralization. Methods: Five-millimeter long fragments obtained from the mead femoral region of male Wistar rats were assigned into group A (n=10, laser) and group B (n=10, no laser), submitted to mechanic and enzymatic digestion. After 7 days, cultures of group A were irradiated daily on a single spot with a GaInAs laser, λ=808nm, 200mW/cm2, 2J/cm2, bean diameter of 0,02mm, 5 seconds for 6 days. Group B was manipulated but received no laser irradiation. After 13 days the cells were trypsinized for 15 minute and stabilized with RNA later® for RNA extraction with Trizol®. cDNA synthesis used 10μg of RNA and M-MLV® enzyme. PCR was accomplished using the β-actin gene as a control. Another aliquot was fixed for Hematoxylin-Eosin and Von Kossa staining to visualize bone mineralization areas. Results: Under UV light we observed clearly the amplification of β-actin gene around 400bp. HE and Von Kossa staining showed osteoblast clusters, a higher number of bone cells and well defined mineralization areas in group A. Conclusion: The cell culture, RNA extraction and RT-PCR method for adult osteoblasts was effective, allowing to use these methods for bone mineralization studies. Laser improved bone mineralization and further studies are needed involving osteogenesis, calcium release mechanisms and calcium related channels.

  3. Mineral resource of the month: Vermiculite

    USGS Publications Warehouse

    Tanner, Arnold O.

    2014-01-01

    Vermiculite comprises a group of hydrated, laminar magnesium-aluminum-iron silicate minerals resembling mica. They are secondary minerals, typically altered biotite, iron-rich phlogopite or other micas or clay-like minerals that are themselves sometimes alteration products of amphibole, chlorite, olivine and pyroxene. Vermiculite deposits are associated with volcanic ultramafic rocks rich in magnesium silicate minerals, and flakes of the mineral range in color from black to shades of brown and yellow. The crystal structure of vermiculite contains water molecules, a property that is critical to its processing for common uses.

  4. Scenarios for Low Carbon and Low Water Electric Power Plant Operations: Implications for Upstream Water Use.

    PubMed

    Dodder, Rebecca S; Barnwell, Jessica T; Yelverton, William H

    2016-11-01

    Electric sector water use, in particular for thermoelectric operations, is a critical component of the water-energy nexus. On a life cycle basis per unit of electricity generated, operational (e.g., cooling system) water use is substantially higher than water demands for the fuel cycle (e.g., natural gas and coal) and power plant manufacturing (e.g., equipment and construction). However, could shifting toward low carbon and low water electric power operations create trade-offs across the electricity life cycle? We compare business-as-usual with scenarios of carbon reductions and water constraints using the MARKet ALlocation (MARKAL) energy system model. Our scenarios show that, for water withdrawals, the trade-offs are minimal: operational water use accounts for over 95% of life cycle withdrawals. For water consumption, however, this analysis identifies potential trade-offs under some scenarios. Nationally, water use for the fuel cycle and power plant manufacturing can reach up to 26% of the total life cycle consumption. In the western United States, nonoperational consumption can even exceed operational demands. In particular, water use for biomass feedstock irrigation and manufacturing/construction of solar power facilities could increase with high deployment. As the United States moves toward lower carbon electric power operations, consideration of shifting water demands can help avoid unintended consequences.

  5. Soil Organic Matter Stabilization via Mineral Interactions in Forest Soils with Varying Saturation Frequency

    NASA Astrophysics Data System (ADS)

    Possinger, A. R.; Inagaki, T.; Bailey, S. W.; Kogel-Knabner, I.; Lehmann, J.

    2017-12-01

    Soil carbon (C) interaction with minerals and metals through surface adsorption and co-precipitation processes is important for soil organic C (SOC) stabilization. Co-precipitation (i.e., the incorporation of C as an "impurity" in metal precipitates as they form) may increase the potential quantity of mineral-associated C per unit mineral surface compared to surface adsorption: a potentially important and as yet unaccounted for mechanism of C stabilization in soil. However, chemical, physical, and biological characterization of co-precipitated SOM as such in natural soils is limited, and the relative persistence of co-precipitated C is unknown, particularly under dynamic environmental conditions. To better understand the relationships between SOM stabilization via organometallic co-precipitation and environmental variables, this study compares mineral-SOM characteristics across a forest soil (Spodosol) hydrological gradient with expected differences in co-precipitation of SOM with iron (Fe) and aluminum (Al) due to variable saturation frequency. Soils were collected from a steep, well-drained forest soil transect with low, medium, and high frequency of water table intrusion into surface soils (Hubbard Brook Experimental Forest, Woodstock, NH). Lower saturation frequency soils generally had higher C content, C/Fe, C/Al, and other indicators of co-precipitation interactions resulting from SOM complexation, transport, and precipitation, an important process of Spodosol formation. Preliminary Fe X-ray Absorption Spectroscopic (XAS) characterization of SOM and metal chemistry in low frequency profiles suggest co-precipitation of SOM in the fine fraction (<20 µm). Short-term (10d) aerobic incubation of high and low saturation frequency soils showed greater SOC mineralization per unit soil C for low saturation frequency (i.e., higher co-precipitation) soils; however, increased mineralization may be attributed to non-mineral associated fractions of SOM. Further work to

  6. Did Water Leave Its Mark on Mars?

    ERIC Educational Resources Information Center

    Secosky, James J.

    1989-01-01

    Discusses the missing water on Mars. Describes five experiments simulating conditions on Mars: (1) behavior of dry ice; (2) low-pressure vacuum; (3) freezing point depression; (4) water in hydrated minerals and clay; and (5) properties of carbon dioxide. (YP)

  7. Effect of mineral and organic fertilization on grey water footprint in a fertirrigated crop under semiarid conditions.

    NASA Astrophysics Data System (ADS)

    Castellanos Serrano, María Teresa; Requejo Mariscal, María Isabel; Cartagena Causapé, María Carmen; Arce Martínez, Augusto; Ribas Elcorobarrutia, Francisco; Jesús Cabello Cabello, María; María Tarquis Alfonso, Ana

    2016-04-01

    The concept of "water footprint" (WF) was introduced as an indicator for the total volume of direct and indirect freshwater used, consumed and/or polluted [1]. The WF distinguishes between blue water (volume of surface and groundwater consumed), green water (rain-water consumed), and grey water (volume of freshwater that is required to assimilate the load of pollutants based on existing ambient water quality standards). In semiarid scenarios with low water quality, where the irrigation is necessary to maintain production, green WF is zero because the effective rainfall is negligible. As well as blue WF includes: i) extra consumption or irrigation water that the farmer has to apply to compensate the fail of uniformity on discharge of drips, ii) percolation out of control or salts leaching, which depends on the salt tolerance of the crop, soil and quality of irrigation water, to ensure the fruit yield. The major concern is grey WF, because the irrigation and nitrogen dose have to be adjusted to the crop needs in order to minimize nitrate pollution. This study is focused in assessment mineral and organic fertilization on grey WF in a fertirrigated melon crop under semiarid conditions, which is principally cultivated in the centre of Spain declared vulnerable zone to nitrate pollution by applying the Directive 91/676/CEE. During successive years, a melon crop (Cucumis melo L.) was grown under field conditions. Different doses of ammonium nitrate were used as well as compost derived from the wine-distillery industry which is relevant in this area. Acknowledgements: This project has been supported by INIA-RTA04-111-C3 and INIA-RTA2010-00110-C03. Keywords: Water footprint, nitrogen, fertirrigation, inorganic fertilizers, organic amendments, semiarid conditions. [1] Hoekstra, A.Y. 2003. Virtual water trade. Proceedings of the International Expert Meeting on Virtual Water Trade, Delft, The Netherlands, 12-13 December 2002. Value of Water Research Report Series No. 12

  8. Low Bone Mineral Density Risk Factors and Testing Patterns in Institutionalized Adults with Intellectual and Developmental Disabilities

    ERIC Educational Resources Information Center

    Hess, Mailee; Campagna, Elizabeth J.; Jensen, Kristin M.

    2018-01-01

    Background: Adults with intellectual or developmental disability (ID/DD) have multiple risks for low bone mineral density (BMD) without formal guidelines to guide testing. We sought to identify risk factors and patterns of BMD testing among institutionalized adults with ID/DD. Methods: We evaluated risk factors for low BMD (Z-/T-score < -1) and…

  9. X-ray and simulation studies of water

    NASA Astrophysics Data System (ADS)

    Nilsson, A.; Schlesinger, D.; G. M. Pettersson, L.

    Here we present a picture that combines discussions regarding the thermodynamic anomalies in ambient and supercooled water with recent interpretations of X-ray spectroscopy and scattering data of water. At ambient temperatures most molecules favor a closer packing than tetrahedral, with strongly distorted hydrogen bonds, which allows the quantized librational modes to be excited and contribute to the entropy, but with enthalpically favored tetrahedrally bonded water patches appearing as fluctuations, a competition between entropy and enthalpy. Upon cooling water the amount of molecules participating in tetrahedral structures and the size of the tetrahedral patches increase. The two local structures are connected to the liquid-liquid critical point hypothesis in supercooled water corresponding to high-density liquid (HDL) and low-density liquid (LDL). We demonstrate that the HDL local structure deviates from a tetrahedral coordination not only through a collapse of the 2nd shell but also through severe distortions around the 1st coordination shell.

  10. Trace Element Speciation and Distribution Study at Shewanella oneidensis MR-1 Biofilm/Mineral/Water Interfaces

    NASA Astrophysics Data System (ADS)

    Gelabert, A.; Wang, Y.; Gescher, J.; Ha, J.; Cordova, C. D.; Singer, D. M.; Spormann, A. M.; Trainor, T. P.; Eng, P. J.; Brown, G. E.

    2006-12-01

    Fe- and Al-(oxyhydr)oxides are among the most reactive mineral surfaces contacted by surface and ground waters, and thus they constitute important sorbents for heavy metal and metalloid ions. As microbial biofilms may be present as coatings on these minerals, they are likely to induce major changes in surface charges and sorption capacities for metal(loid) ions compared to biofilm-free mineral surfaces. In addition, the micro- environments in biofilms can be quite different from those in bulk solutions, which can enhance (or inhibit) metal adsorption on mineral surfaces and produce biominerals that are not predicted by equilibrium thermodynamics based on the bulk solution values. In order to provide a more quantitative understanding of these effects, we have carried out a study of the interaction of Zn(II), Pb(II), and As(V) with Shewanella oneidensis (wild type, EPS-deficient mutant, and ppx- and ppk-deficient mutants) grown on highly polished and oriented single crystal surfaces of α-Al2O3 (1-102) and α-Fe2O3 (0001). This gram-negative bacterium commonly found in soil and sediments can use a wide range of electron donors and terminal electron acceptors including Fe(III) and Mn(IV) oxides under anaerobic conditions. In-situ ATR-FTIR analyses and potentiometric titrations of S. oneidensis biofilm collected from a glass bead-filled column inoculated with S. oneidensis were conducted in order to determine the nature of functional groups present on the bacterial surfaces, to quantify the site densities and protonation constants for these groups, and to determine the electrostatic parameters for S. oneidensis surfaces. GI-XAFS analyses performed on BL 11-2 at SSRL, together with macroscopic metal adsorption experiments as a function of pH (2 to 6.5), metal concentration (10-3 to 10-7 M), and ionic strength (10-1 to 10-3 M), were used to determine ion speciation and local coordination environments in the biofilm and to develop a surface complexation model describing

  11. Investigation of wood combustion in the high-enthalpy oxidizer flow

    NASA Astrophysics Data System (ADS)

    Reshetnikov, S. M.; Zyryanov, I. A.; Budin, A. G.; Pozolotin, A. P.

    2017-01-01

    The experimental data of wood combustion in the high-enthalpy oxidizer flowresearch is presented. Combustion laws of two wood species (pine and birch) in a hybrid rocket engine (HRE) are obtained. Heat flows from the flame to the condensed phase surface are defined. The prospects of the wood use in the HRE (based on thrust characteristics) are shown.

  12. High fluoride and low calcium levels in drinking water is associated with low bone mass, reduced bone quality and fragility fractures in sheep.

    PubMed

    Simon, M J K; Beil, F T; Rüther, W; Busse, B; Koehne, T; Steiner, M; Pogoda, P; Ignatius, A; Amling, M; Oheim, R

    2014-07-01

    Chronic environmental fluoride exposure under calcium stress causes fragility fractures due to osteoporosis and bone quality deterioration, at least in sheep. Proof of skeletal fluorosis, presenting without increased bone density, calls for a review of fracture incidence in areas with fluoridated groundwater, including an analysis of patients with low bone mass. Understanding the skeletal effects of environmental fluoride exposure especially under calcium stress remains an unmet need of critical importance. Therefore, we studied the skeletal phenotype of sheep chronically exposed to highly fluoridated water in the Kalahari Desert, where livestock is known to present with fragility fractures. Dorper ewes from two flocks in Namibia were studied. Chemical analyses of water, blood and urine were executed for both cohorts. Skeletal phenotyping comprised micro-computer tomography (μCT), histological, histomorphometric, biomechanical, quantitative backscattered electron imaging (qBEI) and energy-dispersive X-ray (EDX) analysis. Analysis was performed in direct comparison with undecalcified human iliac crest bone biopsies of patients with fluoride-induced osteopathy. The fluoride content of water, blood and urine was significantly elevated in the Kalahari group compared to the control. Surprisingly, a significant decrease in both cortical and trabecular bones was found in sheep chronically exposed to fluoride. Furthermore, osteoid parameters and the degree and heterogeneity of mineralization were increased. The latter findings are reminiscent of those found in osteoporotic patients with treatment-induced fluorosis. Mechanical testing revealed a significant decrease in the bending strength, concurrent with the clinical observation of fragility fractures in sheep within an area of environmental fluoride exposure. Our data suggest that fluoride exposure with concomitant calcium deficit (i) may aggravate bone loss via reductions in mineralized trabecular and cortical bone

  13. Prevalence of low bone mineral density in female dancers.

    PubMed

    Amorim, Tânia; Wyon, Matthew; Maia, José; Machado, José Carlos; Marques, Franklim; Metsios, George S; Flouris, Andreas D; Koutedakis, Yiannis

    2015-02-01

    While some authors report that dancers have reduced bone mineral density (BMD) and increased risk of osteoporosis, others have stressed the positive effects of dance training on developing healthy BMD. Given the existing controversy, the aim of this systematic review was to examine the best evidence-based information available in relation to female dancers. Four databases (Web of Science, PubMed, EBSCO, Scopus) and two dance science journals (Journal of Dance Medicine and Science and Medical Problems of Performing Artists) were searched for relevant material using the keywords "dance", "ballet", "BMD", "bone density", "osteoporosis" and "female athlete triad syndrome". A total of 257 abstracts were screened using selected inclusion (studies involving bone measurements in dancers) and exclusion (editorials, opinion papers, chapters in books, narrative reviews and non-English language papers) criteria according to PRISMA guidelines. Following the above screening, a total of 108 abstracts were identified as potentially relevant. After the exclusion of conference proceedings, review papers, studies focusing only in male dancers and studies in which dancers' information were combined with other athletes, the eligible papers were subsequently assessed using the GRADE system and grouped according to: (1) prevalence of low BMD and associated factors, (2) incidence of low BMD and risk factors, (3) prevention/treatment of low BMD in dancers, and (4) other studies. Of the 257 abstracts that were initially screened, only 35 studies were finally considered. Only one of these 35 was of high quality, while the remaining 34 were of relatively low quality. Seven studies reported prevalence of low BMD and associated factors, 10 reported associated factors with no prevalence data, while one reported prevalence with no associated factors data. One study cited risk factors, while another one elaborated on the treatment of low BMD in dancers. The remaining 15 studies were classified as

  14. Evidence for interfacial dissolution-precipitation during low-temperature mineral weathering

    NASA Astrophysics Data System (ADS)

    Ruiz-Agudo, Encarnacion; Putnis, Christine V.; Rodriguez-Navarro, Carlos; Putnis, Andrew

    2013-04-01

    The dissolution of most common multicomponent minerals and glasses is typically "incongruent" as shown by the nonstoichiometric release of the solid phase components. This frequently results in the formation of so-called surface leached layers. The mechanism of this process has been a recurrent subject of research and debate over the past two decades, due to its relevance to a wide range of natural and technological processes, as well as being crucial in defining rate laws for mineral reactions. Here we report experimental, in situ nanoscale observations that confirm the formation of a cation depleted layer at the mineral-solution interface during dissolution of multicomponent minerals at acidic pH. Our in situ Atomic Force Microscopy studies of the dissolution of wollastonite, CaSiO3, and dolomite, Ca0.5Mg0.5CO3, combined with compositional analysis of reaction products, provide, for the first time, clear direct experimental evidence that cation-depleted (i.e. leached) layers are formed in a tight interface-coupled two step process: stoichiometric dissolution of the pristine mineral surfaces and subsequent precipitation of a secondary phase from a supersaturated boundary layer of fluid in contact with the mineral surface. Such a mechanism presents a new paradigm that differs from the concept of preferential leaching of cations, as postulated by most currently accepted incongruent dissolution models. References Ruiz Agudo, E; Putnis, CV; Rodríguez Navarro, C and Putnis, A. (2012) Mechanism of leached layer formation during chemical weathering of silicate minerals. Geology, 40, 947-950 Urosevic, M; Rodríguez Navarro,C; Putnis, CV; Cardell, C; Putnis, A and Ruiz Agudo, E (2012) In situ nanoscale observations of the dissolution of [10-14] dolomite cleavage surfaces. Geochimica et Cosmochimica Acta, 80, 1-13

  15. Grism manufacturing by low temperature mineral bonding

    NASA Astrophysics Data System (ADS)

    Kalkowski, G.; Grabowski, K.; Harnisch, G.; Flügel-Paul, T.; Zeitner, U.; Risse, S.

    2017-09-01

    By uniting a grating with a prism to a GRISM compound, the optical characteristics of diffractive and refractive elements can be favorably combined to achieve outstanding spectral resolution features. Ruling the grating structure into the prism surface is common for wavelengths around 1 μm and beyond, while adhesive bonding of two separate parts is generally used for shorter wavelengths and finer structures. We report on a manufacturing approach for joining the corresponding glass elements by the technology of hydrophilic direct bonding. This allows to manufacture the individual parts separately and subsequently combine them quasimonolithically by generating stiff and durable bonds of vanishing thickness, high strength and excellent transmission. With this approach for GRISM bonding, standard direct-write- or mask-lithography equipment may be used for the fabrication of the grating structure and the drawbacks of adhesive bonding (thermal mismatch, creep, aging) are avoided. The technology of hydrophilic bonding originates from "classical" optical contacting [1], but has been much improved and perfected during the last decades in the context of 3-dimensinal stacking Si-wafers for microelectronic applications [2]. It provides joins through covalent bonds of the Si-O-Si type at the nanometer scale, i.e. the elementary bond type in many minerals and glasses. The mineral nature of the bond is perfectly adapted to most optical materials and the extremely thin bonding layers generated with this technology are well suited for transmission optics. Creeping under mechanical load, as commonly observed with adhesive bonding, is not an issue. With respect to diffusion bonding, which operates at rather high temperatures close to the glass transition or crystal melting point, hydrophilic bonding is a low temperature process that needs only moderate heating. This facilitates provision of handling and alignment means for the individual parts during the set-up stages and greatly

  16. Ground-Water Geochemistry of Kwajalein Island, Republic of the Marshall Islands, 1991

    USGS Publications Warehouse

    Tribble, Gordon W.

    1997-01-01

    Ground water on Kwajalein Island is an important source of drinking water, particularly during periods of low rainfall. Fresh ground water is found as a thin lens underlain by saltwater. The concentration of dissolved ions increases with depth below the water table and proximity to the shoreline as high-salinity seawater mixes with fresh ground water. The maximum depth of the freshwater lens is 37 ft. Chloride is assumed to be non-reactive under the range of geochemical conditions on the atoll. The concentration of chloride thus is used as a conservative constituent to evaluate freshwater-saltwater mixing within the aquifer. Concentrations of sodium and for the most part, potassium and sulfate, also appear to be determined by conservative mixing between saltwater and rain. Concentrations of calcium, magnesium, and strontium are higher than expected from conservative mixing; these higher concentrations are a result of the dissolution of carbonate minerals. An excess in dissolved inorganic carbon results from carbonate-mineral dissolution and from the oxidation of organic matter in the aquifer; the stoichiometric difference between excess dissolved inorganic carbon and excess bivalent cations is used as a measure of the amount of organic-matter oxidation. Organic-matter oxidation also is indicated by the low concentration of dissolved oxygen, high concentrations of nutrients, and the presence of hydrogen sulfide in many of the water samples. Low levels of dissolved oxygen indicate oxic respiration, and sulfate reduction is indicated by hydrogen sulfide. The amount of dissolved inorganic carbon released during organic-matter oxidation is nearly equivalent to the amount of carbonate-mineral dissolution. Organic-matter oxidation and carbonate-mineral dissolution seem to be most active either in the unsaturated zone or near the top of the water table. The most plausible explanation is that high amounts of oxic respiration in the unsaturated zone generate carbon dioxide

  17. Very Tiny Rocks: Site-Specific, Size-Dependent Reaction Kinetics at Nanoparticle-Water Interfaces

    NASA Astrophysics Data System (ADS)

    Rustad, J. R.

    2008-12-01

    One of the most fundamental challenges in geochemistry is to be able to understand the rates and mechanisms of elementary reactions that describe chemical processes occurring at mineral-water interfaces. One of the reasons for the primitive conceptual state of reaction kinetics in solid earth geochemistry is that it is very difficult to identify defensible elementary reactions where theoretical predictions can be made and the results can tested experimentally at the same length and time scale of the prediction. For example, the most fundamental predictor of complexation kinetics in aqueous solution is the characteristic water exchange rate, which are well known for the aquo ions and vary by 20 orders of magnitude even for simple trivalent ions. In contrast, for interfacial reactions, it was not even known whether water exchange rates were faster or slower than equivalent metal sites in solution, prohibiting any quantitive understanding of mineral reaction kinetics at the molecular level. Recent advances in synthesis and characterization of materials at nanometer length scales has been able to bridge the gap in scale, and nanometer-sized minerals have given us our first quantitative understanding of elementary reaction rates for fundamental processes involving water and hydroxide exchange reactions. I describe the results of molecular dynamics calculation and experimental measurement of the rates of water, hydroxide, and proton exchange reactions on nanoparticle surfaces. The calculations already show that transition state theory is completely inadequate to understand the rates of even the simplest elementary reactions. Furthermore, the mechanistic implications of rate parameters such as activation volume and activation enthalpy may be different in moving from aquo ions to interfaces. Is a molecular understanding of geochemical processes really needed? One might have asked a biologist at the turn of the century whether studying the structure of proteins would ever

  18. Low-rank coal oil agglomeration

    DOEpatents

    Knudson, C.L.; Timpe, R.C.

    1991-07-16

    A low-rank coal oil agglomeration process is described. High mineral content, a high ash content subbituminous coals are effectively agglomerated with a bridging oil which is partially water soluble and capable of entering the pore structure, and is usually coal-derived.

  19. The calculation of aquifer chemistry in hot-water geothermal systems

    USGS Publications Warehouse

    Truesdell, Alfred H.; Singers, Wendy

    1974-01-01

    The temperature and chemical conditions (pH, gas pressure, and ion activities) in a geothermal aquifer supplying a producing bore can be calculated from the enthalpy of the total fluid (liquid + vapor) produced and chemical analyses of water and steam separated and collected at known pressures. Alternatively, if a single water phase exists in the aquifer, the complete analysis (including gases) of a sample collected from the aquifer by a downhole sampler is sufficient to determine the aquifer chemistry without a measured value of the enthalpy. The assumptions made are that the fluid is produced from a single aquifer and is homogeneous in enthalpy and chemical composition. These calculations of aquifer chemistry involving large amounts of ancillary information and many iterations require computer methods. A computer program in PL-1 to perform these calculations is available from the National Technical Information Service as document PB-219 376.

  20. Uniform nanoparticles by flame-assisted spray pyrolysis (FASP) of low cost precursors

    PubMed Central

    Rudin, Thomas; Wegner, Karsten

    2013-01-01

    A new flame-assisted spray pyrolysis (FASP) reactor design is presented, which allows the use of inexpensive precursors and solvents (e.g., ethanol) for synthesis of nanoparticles (10–20 nm) with uniform characteristics. In this reactor design, a gas-assisted atomizer generates the precursor solution spray that is mixed and combusted with externally fed inexpensive fuel gases (acetylene or methane) at a defined height above the atomizing nozzle. The gaseous fuel feed can be varied to control the combustion enthalpy content of the flame and onset of particle formation. This way, the enthalpy density of the flame is decoupled from the precursor solution composition. Low enthalpy content precursor solutions are prone to synthesis of non-uniform particles (e.g., bimodal particle size distribution) by standard flame spray pyrolysis (FSP) processes. For example, metal nitrates in ethanol typically produce nanosized particles by gas-to-particle conversion along with larger particles by droplet-to-particle conversion. The present FASP design facilitates the use of such low enthalpy precursor solutions for synthesis of homogeneous nanopowders by increasing the combustion enthalpy density of the flame with low-cost, gaseous fuels. The effect of flame enthalpy density on product properties in the FASP configuration is explored by the example of Bi2O3 nanoparticles produced from bismuth nitrate in ethanol. Product powders were characterized by nitrogen adsorption, X-ray diffraction, X-ray disk centrifuge, and transmission electron microscopy. Homogeneous Bi2O3 nanopowders were produced both by increasing the gaseous fuel content and, most notably, by cutting the air entrainment prior to ignition of the spray. PMID:23408113

  1. Mineral resources of Novokuznetsk administrative district of Kemerovo region (metallic and non-metallic minerals)

    NASA Astrophysics Data System (ADS)

    Gutak, Ja M.

    2017-09-01

    The article summarizes data on metallic and non-metallic minerals of Novokuznetsk district of Kemerovo region. Consistently reviewed are iron deposits (Tersinskaya group of deposits), gold deposits (placer accumulations and vein gold deposits), mineral water deposits (Tersinskoe deposit), deposit of refractory clay (Barkinskoe) and wide spread mineral deposits such as brick clay, keramzite materials, sand and gravel, building stones, ornamental stones, facing stones, peat, materials for lime production. It is indicated that resource base of metallic and nonmetallic minerals is inferior to that of mineral coal. At the same time it can be of considerable interest to small and medium-size businesses as objects with quick return of investment (facing and ornamental stones). For a number of wide spread mineral resources (brick clay, keramzite materials, sand and gravel) it is an important component of local industry.

  2. Analysis of Economic Efficiency of Production of Low-Concentrated Sodium Hypochlorite by Direct Electrolysis of Natural Waters

    NASA Astrophysics Data System (ADS)

    Fesenko, L. N.; Pchelnikov, I. V.; Fedotov, R. V.

    2017-11-01

    The study presents the economic efficiency of direct electrolysis of natural waters in comparison with the waters artificially prepared by electrolysis of the 3% sodium salt solution. The study used sea water (Black sea water); mineral water (underground water of the Melikhovskaya station, “Ognennaya” hole); brackish water (underground water from the Grushevskaya station of the Aksai district); 3% solution of sodium salt. As a result, the dependences characterizing the direct electrolysis of natural waters with different mineralization, economic, and energy parties are shown. The rational area of the electrolysis for each of the investigated solution is determined. The cost of a kilogram of active chlorine obtained by the direct water electrolysis: Black sea from 17.2 to 18.3 RUB/kg; the Melikhovskaya station “Ognennaya” hole - 14.3 to 15.0 Rubles/kg; 3% solution of NaCl - 30 Rubles./kg; Grushevskogo St. - 63,0-73,0 Rubles/kg.

  3. Investigation of applicability of Electro-Fenton method for the mineralization of naphthol blue black in water.

    PubMed

    Özcan, Ayça Atılır; Özcan, Ali

    2018-07-01

    In this study, mineralization and color removal performance of electro-Fenton method were examined in water containing naphthol blue black (NBB), a diazo dye. NBB was totally converted to intermediate species in a 15-min electrolysis at 60 mA, but complete de-colorization took 180 min. A very high oxidation rate constant ((3.35 ± 0.21) x 10 10  M -1 s -1 ) was obtained for NBB, showing its high reactivity towards hydroxyl radicals. A very high total organic carbon (TOC) removal value (45.23 mg L -1 ) was obtained in the first 60 min of the electro-Fenton treatment of an aqueous solution of NBB (0.25 mM) at 300 mA, indicating the mineralization efficiency of the electro-Fenton method. Mineralization current efficiency values obtained at 300 mA gradually decreased from 24.18% to 4.47% with the electrolysis time, indicating the presence of highly parasitic reactions. Gas chromatography-mass spectrometry analyses revealed that the cleavage of azo bonds of NBB led to formation of different aromatic and aliphatic oxidation intermediates. Ion chromatography analysis showed that ammonium, nitrate and sulfate were the mineralization end-products. The concentration of sulfate ion reached to its quantitative value at the 4th h of electrolysis. On the other hand, the total concentration of ammonium and nitrate ions reached to only 61% of the stoichiometric amount of initial nitrogen after a 7 h electrolysis. Finally, it can be said that the electro-Fenton method is a suitable and efficient method for the removal of NBB and its intermediates from water. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Study of Some Mineral Exchangers for Use in Water at High Temperature; ETUDE DE QUELQUES ECHANGEURS MINERAUX UTILISABLES DANS L'EAU A HAUTE TEMPERATURE

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hure, J.; Platzer, R.; Bittel, R.

    1959-10-31

    The study of the use of ion exchangers at high temperatures was made with a view to the purification of water in reactors. Natural ion exchangers with mineral structures (clay of the montmorillonite type), natural mineral compounds so treated as to give them the properties of ion exchangers (activated graphite), and synthetic mineral compounds (zirconium phosphates and hydroxides and thorium hydroxide) were investigated. The preparation of the minerals is described, and the results obtained with them are discussed in detail. (J.S.R.)

  5. Mapping playa evaporite minerals with AVIRIS data: A first report from death valley, California

    USGS Publications Warehouse

    Crowley, J.K.

    1993-01-01

    Efflorescent salt crusts in Death Valley, California, were mapped by using Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and a recently developed least-squares spectral band-fitting algorithm. Eight different saline minerals were remotely identified, including three borates, hydroboracite, pinnoite, and rivadavite, that have not been previously reported from the Death Valley efflorescent crusts. The three borates are locally important phases in the crusts, and at least one of the minerals, rivadavite, appears to be forming directly from brine. Borates and other evaporite minerals provide a basis for making remote chemical measurements of desert hydrologic systems. For example, in the Eagle Borax Spring area, the AVIRIS mineral maps pointed to elevated magnesium and boron levels in the ground waters, and to the action of chemical divides causing subsurface fractionation of calcium. Many other chemical aspects of playa brines should have an expression in the associated evaporite assemblages. Certain anhydrous evaporites, including anhydrite, glauberite, and thenardite, lack absorption bands in the visible and near-infrared wavelength range, and crusts composed of these minerals could not be characterized by using AVIRIS. In these situations, thermal-infrared remote sensing data may complement visible and near-infrared data for mapping evaporites. Another problem occurred in wet areas of Death Valley, where water absorption caused low signal levels in the 2.0-2.5 ??m wavelength region that obscured any spectral features of evaporite minerals. Despite these difficulties, the results of this study demonstrate the potential for using AVIRIS and other imaging spectrometer data to study playa chemistry. Such data can be useful for understanding chemical linkages between evaporites and ground waters, and will facilitate studies of how desert ground-water regimes change through time in response to climatic and other variables. ?? 1993.

  6. Mineral Tells Tale of Watery Past-2

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This spectrum, taken by the Mars Exploration Rover Opportunity's Moessbauer spectrometer, shows the presence of an iron-bearing mineral called jarosite in the collection of rocks dubbed 'El Capitan.' 'El Capitan' is located within the outcrop that lines the inner edge of the small crater where Opportunity landed. The pair of yellow peaks specifically indicates a jarosite phase, which contains water in the form of hydroxyl as a part of its structure. These data suggest water-driven processes exist on Mars. Three other phases are also identified in this spectrum: a magnetic phase (blue), attributed to an iron-oxide mineral; a silicate phase (green), indicative of minerals containing double-ionized iron (Fe 2+); and a third phase (red) of minerals with triple-ionized iron (Fe 3+).

  7. Influence of Countercation Hydration Enthalpies on the Formation of Molecular Complexes: A Thorium–Nitrate Example

    DOE PAGES

    Jin, Geng Bang; Lin, Jian; Estes, Shanna L.; ...

    2017-11-17

    Here, the influence of countercations (A n+) in directing the composition of monomeric metal–ligand (ML) complexes that precipitate from solution are often overlooked despite the wide usage of A n+ in materials synthesis. Herein, we describe a correlation between the composition of ML complexes and A + hydration enthalpies found for two related series of thorium (Th)–nitrate molecular compounds obtained by evaporating acidic aqueous Th–nitrate solutions in the presence of A + counterions. Analyses of their chemical composition and solid-state structures demonstrate that A + not only affects the overall solid-state packing of the Th–nitrato complexes but also influences themore » composition of the Th–nitrato monomeric anions themselves. Trends in composition and structure are found to correlate with A + hydration enthalpies, such that the A + with smaller hydration enthalpies associate with less hydrated and more anionic Th–nitrato complexes. This perspective, broader than the general assumption of size and charge as the dominant influence of A n+, opens a new avenue for the design and synthesis of targeted metal–ligand complexes.« less

  8. Influence of Countercation Hydration Enthalpies on the Formation of Molecular Complexes: A Thorium–Nitrate Example

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jin, Geng Bang; Lin, Jian; Estes, Shanna L.

    Here, the influence of countercations (A n+) in directing the composition of monomeric metal–ligand (ML) complexes that precipitate from solution are often overlooked despite the wide usage of A n+ in materials synthesis. Herein, we describe a correlation between the composition of ML complexes and A + hydration enthalpies found for two related series of thorium (Th)–nitrate molecular compounds obtained by evaporating acidic aqueous Th–nitrate solutions in the presence of A + counterions. Analyses of their chemical composition and solid-state structures demonstrate that A + not only affects the overall solid-state packing of the Th–nitrato complexes but also influences themore » composition of the Th–nitrato monomeric anions themselves. Trends in composition and structure are found to correlate with A + hydration enthalpies, such that the A + with smaller hydration enthalpies associate with less hydrated and more anionic Th–nitrato complexes. This perspective, broader than the general assumption of size and charge as the dominant influence of A n+, opens a new avenue for the design and synthesis of targeted metal–ligand complexes.« less

  9. Numerical Investigation of Double-Cone Flows with High Enthalpy Effects

    NASA Astrophysics Data System (ADS)

    Nompelis, I.; Candler, G. V.

    2009-01-01

    A numerical study of shock/shock and shock/boundary layer interactions generated by a double-cone model that is placed in a hypersonic free-stream is presented. Computational results are compared with the experimental measurements made at the CUBRC LENS facility for nitrogen flows at high enthalpy conditions. The CFD predictions agree well with surface pressure and heat-flux measurements for all but one of the double-cone cases that have been studied by the authors. Unsteadiness is observed in computations of one of the LENS cases, however for this case the experimental measurements show that the flowfield is steady. To understand this discrepancy, several double-cone experiments performed in two different facilities with both air and nitrogen as the working gas are examined in the present study. Computational results agree well with measurements made in both the AEDC tunnel 9 and the CUBRC LENS facility for double-cone flows at low free-stream Reynolds numbers where the flow is steady. It is shown that at higher free- stream pressures the double-cone simulations develop instabilities that result in an unsteady separation.

  10. Problem-based learning in teaching chemistry: enthalpy changes in systems

    NASA Astrophysics Data System (ADS)

    Ayyildiz, Yildizay; Tarhan, Leman

    2018-01-01

    Problem-based learning (PBL) as a teaching strategy has recently become quite widespread in especially chemistry classes. Research has found that students, from elementary through college, have many alternative conceptions regarding enthalpy changes in systems. Although there are several studies focused on identifying student alternative conceptions and misunderstandings of this subject, studies on preventing the formation of these alternative conceptions are limited.

  11. [Prevalence of low bone mineral density in postmenopausal breast cancer survivors].

    PubMed

    Poloni, Priscila Ferreira; Omodei, Michelle Sako; Nahas-Neto, Jorge; Uemura, Gilberto; Véspoli, Heloisa De Luca; Nahas, Eliana Aguiar Petri

    2015-01-01

    To evaluate the prevalence of low bone mineral density (BMD) in postmenopausal breast cancer survivors. In this cross-sectional study, 115 breast cancer survivors, seeking healthcare at a University Hospital in Brazil, were evaluated. Eligibility criteria included women with amenorrhea ≥ 12 months and age ≥ 45 years, treated for breast cancer and metastasis-free for at least five years. BMD was measured by DEXA at the lumbar spine (L1-L4) and femoral neck. Low BMD was considered when total-spine and/or femoral-neck T-score values were <-1.0 Delphi Score (DP) (osteopenia and osteoporosis). The risk factors for low BMD were assessed by interview. Data were analyzed statistically by the χ(2) test and Fisher's exact test. The mean age of breast cancer survivors was 61.6 ± 10.1 years and time since menopause was 14.2 ± 5.6 years, with a mean follow-up of 10.1 ± 3.9 years. Considering spine and femoral neck, 60% of breast cancer survivors had low BMD. By evaluating the risk factors for low BMD, a significant difference was found in the percent distribution for age (higher % of women >50 years with low BMD), personal history of previous fracture (11.6% with low BMD versus 0% with normal BMD) and BMI. A higher frequency of obesity was observed among women with normal BMD (63%) compared to those with low BMD (26.1%) (p<0.05). Postmenopausal breast cancer survivors had a high prevalence of osteopenia and osteoporosis.

  12. Geophysical ore guides along the Colorado mineral belt

    USGS Publications Warehouse

    Case, James E.

    1967-01-01

    A 40-50-mgal gravity low trends northeast along the Colorado mineral belt between Monarch Pass and Breckenridge, Colorado. The low is probably caused by a silicic Tertiary batholith of lower density than adjacent Precambrian crystalline rocks. Many major mining districts associated with silicic Tertiary intrusives are near the axis of the low. Positive and negative aeromagnetic anomalies are present over the larger silicic Tertiary intrusive bodies. A good correlation exists between the magnetic lows and zones of altered, mineralized porphyry. Apparently, original magnetite in the silicic porphyries has been altered to relatively nonmagnetic pyrite or iron oxides. The regional gravity low aids in defining the limits of the mineral belt, and the magnetic lows over the porphyries indicate specific alteration zones and the possibility of associated mineral deposits.

  13. Computational Evaluation of Mg–Salen Compounds as Subsurface Fluid Tracers: Molecular Dynamics Simulations in Toluene–Water Mixtures and Clay Mineral Nanopores

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Greathouse, Jeffery A.; Boyle, Timothy J.; Kemp, Richard A.

    Molecular tracers that can be selectively placed underground and uniquely identified at the surface using simple on-site spectroscopic methods would significantly enhance subsurface fluid monitoring capabilities. To ensure their widespread utility, the solubility of these tracers must be easily tuned to oil- or water-wet conditions as well as reducing or eliminating their propensity to adsorb onto subsurface rock and/or mineral phases. In this work, molecular dynamics simulations were used to investigate the relative solubilities and mineral surface adsorption properties of three candidate tracer compounds comprising Mg–salen derivatives of varying degrees of hydrophilic character. Simulations in water–toluene liquid mixtures indicate thatmore » the partitioning of each Mg–salen compound relative to the interface is strongly influenced by the degree of hydrophobicity of the compound. Simulations of these complexes in fluid-filled mineral nanopores containing neutral (kaolinite) and negatively charged (montmorillonite) mineral surfaces reveal that adsorption tendencies depend upon a variety of parameters, including tracer chemical properties, mineral surface type, and solvent type (water or toluene). Simulation snapshots and averaged density profiles reveal insight into the solvation and adsorption mechanisms that control the partitioning of these complexes in mixed liquid phases and nanopore environments. As a result, this work demonstrates the utility of molecular simulation in the design and screening of molecular tracers for use in subsurface applications.« less

  14. Computational Evaluation of Mg–Salen Compounds as Subsurface Fluid Tracers: Molecular Dynamics Simulations in Toluene–Water Mixtures and Clay Mineral Nanopores

    DOE PAGES

    Greathouse, Jeffery A.; Boyle, Timothy J.; Kemp, Richard A.

    2018-04-11

    Molecular tracers that can be selectively placed underground and uniquely identified at the surface using simple on-site spectroscopic methods would significantly enhance subsurface fluid monitoring capabilities. To ensure their widespread utility, the solubility of these tracers must be easily tuned to oil- or water-wet conditions as well as reducing or eliminating their propensity to adsorb onto subsurface rock and/or mineral phases. In this work, molecular dynamics simulations were used to investigate the relative solubilities and mineral surface adsorption properties of three candidate tracer compounds comprising Mg–salen derivatives of varying degrees of hydrophilic character. Simulations in water–toluene liquid mixtures indicate thatmore » the partitioning of each Mg–salen compound relative to the interface is strongly influenced by the degree of hydrophobicity of the compound. Simulations of these complexes in fluid-filled mineral nanopores containing neutral (kaolinite) and negatively charged (montmorillonite) mineral surfaces reveal that adsorption tendencies depend upon a variety of parameters, including tracer chemical properties, mineral surface type, and solvent type (water or toluene). Simulation snapshots and averaged density profiles reveal insight into the solvation and adsorption mechanisms that control the partitioning of these complexes in mixed liquid phases and nanopore environments. As a result, this work demonstrates the utility of molecular simulation in the design and screening of molecular tracers for use in subsurface applications.« less

  15. Reference States and Relative Values of Internal Energy, Enthalpy, and Entropy.

    ERIC Educational Resources Information Center

    Fredrickson, A. G.

    1983-01-01

    Discusses two reference states (pure chemical compounds and pure elements at specified condition of temperature and pressure) and the relation between these reference states for internal energy and enthalpy. Problem 5.11 from Modell and Reid's "Thermodynamics and its Applications" (p. 141) is used to apply the ideas discussed. (JN)

  16. The relief of microtherm inhibition for p-fluoronitrobenzene mineralization using electrical stimulation at low temperatures.

    PubMed

    Zhang, Xueqin; Feng, Huajun; Liang, Yuxiang; Zhao, Zhiqing; Long, Yuyang; Fang, Yuan; Wang, Meizhen; Yin, Jun; Shen, Dongsheng

    2015-05-01

    Low temperature aggravates biological treatment of refractory p-fluoronitrobenzene (p-FNB) because of microtherm inhibition of microbial activity. Considering the potential characterization of energy supply for microbial metabolism and spurring microbial activity by electrical stimulation, a bioelectrochemical system (BES) was established to provide sustaining electrical stimulation for p-FNB mineralization at a low temperature. Electrical stimulation facilitated p-FNB treatment and bioelectrochemical reaction rate constants for the removal and defluorination of p-FNB at 10 °C were 0.0931 and 0.0054 h(-1), which were higher than the sums of the rates found using a biological system and an electrocatalytic system by 62.8 and 64.8%, respectively. At a low temperature, microbial activity in terms of dehydrogenase and ATPase was found to be higher with electrical stimulation, being 121.1 and 100.1% more active than that in the biological system. Moreover, stronger antioxidant ability was observed in the BES, which implied a better cold-resistance and relief of microtherm inhibition by electrical stimulation. Bacterial diversity analysis revealed a significant evolution of microbial community by electrical stimulation, and Clostridia was uniquely enriched. One bacterial sequence close to Pseudomonas became uniquely predominant, which appeared to be crucial for excellent p-FNB treatment performance in the BES at a low temperature. Economic evaluation revealed that the energy required to mineralize an extra mole of p-FNB was found to be 247 times higher by heating the system than by application of electrical stimulation. These results indicated that application of electrical stimulation is extremely promising for treating refractory waste at low temperatures.

  17. Calorimetric determination of the enthalpy of 1-butyl-3-methylimidazolium bromide synthesis: a key quantity in thermodynamics of ionic liquids.

    PubMed

    Paulechka, Yauheni U; Kabo, Andrey G; Blokhin, Andrey V

    2009-11-05

    The enthalpy of the 1-butyl-3-methylimidazolium bromide [C(4)mim]Br ionic liquid synthesis reaction 1-methylimidazole (liq) + 1-bromobutane (liq) --> [C(4)mim]Br (liq) was determined in a homemade small-volume isoperibol calorimeter to be Delta(r)H degrees (298) = -87.7 +/- 1.6 kJ x mol(-1). The activation energy for this reaction in a homogeneous system E(A) = 73 +/- 4 kJ x mol(-1) was found from the results of calorimetric measurements. The formation enthalpies for the crystalline and liquid [C(4)mim]Br were determined from the calorimetric data: Delta(f)H degrees (298)(cr) = -178 +/- 5 kJ x mol(-1) and Delta(f)H degrees (298)(liq) = -158 +/- 5 kJ x mol(-1). The ideal-gas formation enthalpy of this compound Delta(f)H degrees (298)(g) = 16 +/- 7 kJ x mol(-1) was calculated using the methods of quantum chemistry and statistical thermodynamics. The vaporization enthalpy of [C(4)mim]Br, Delta(vap)H degrees (298) = 174 +/- 9 kJ x mol(-1), was estimated from the experimental and calculated formation enthalpies. It was demonstrated that vapor pressure of this ionic liquid cannot be experimentally determined.

  18. Low zinc in drinking water is associated with the risk of type 1 diabetes in children.

    PubMed

    Samuelsson, Ulf; Oikarinen, Sami; Hyöty, Heikki; Ludvigsson, Johnny

    2011-05-01

    To explore if drinking water may influence the development of type 1 diabetes in children, either via enterovirus spread via drinking water or quality of drinking water related to acidity or concentration of certain minerals. One hundred and forty-two families with a child with diabetes and who lived either in seven municipalities with a high annual diabetes incidence during 1977-2001 and in six municipalities with the lowest incidence during those 25 yr were asked to participate. Three hundred and seventy-three families in these communities were used as controls. The families filled a 200-mL plastic bottle with their tap drinking water and returned it by mail. The water samples were analyzed for pH, zinc, iron, nitrate, nitrite, nitrate-nitrogen and nitrite-nitrogen, and occurrence of enterovirus RNA. Enterovirus RNA was not found in the tap water samples. The concentration of zinc, nitrate, and nitrate-nitrogen was lower in the municipalities with high incidence of type 1 diabetes. The water samples from families with a child with diabetes had lower concentration of zinc than water samples from control families. Low zinc in drinking water is associated with the risk of developing type 1 diabetes during childhood. Enterovirus does not seem to be spread via drinking water in a country with modern water works. © 2010 John Wiley & Sons A/S.

  19. Mineral Acquisition from Clay by Budongo Forest Chimpanzees.

    PubMed

    Reynolds, Vernon; Lloyd, Andrew W; English, Christopher J; Lyons, Peter; Dodd, Howard; Hobaiter, Catherine; Newton-Fisher, Nicholas; Mullins, Caroline; Lamon, Noemie; Schel, Anne Marijke; Fallon, Brittany

    2015-01-01

    Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms.

  20. Mineral Acquisition from Clay by Budongo Forest Chimpanzees

    PubMed Central

    Reynolds, Vernon; Lloyd, Andrew W.; English, Christopher J.; Lyons, Peter; Dodd, Howard; Hobaiter, Catherine; Newton-Fisher, Nicholas; Mullins, Caroline; Lamon, Noemie; Schel, Anne Marijke; Fallon, Brittany

    2015-01-01

    Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms. PMID:26218593