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Sample records for kcl caoh2 h3po4

  1. PhD Public Defence Title: Degradation of H3PO4/PBI High Temperature Polymer Electrolyte Membrane

    E-print Network

    Schwefel, Hans-Peter

    PhD Public Defence Title: Degradation of H3PO4/PBI High Temperature Polymer Electrolyte Membrane: The Polymer electrolyte membrane (PEM) fuel cells are promising fuel cell technology which can convert temperature of 150 oC. The cell performance loss caused by CO poisoning can be alleviated by the presence

  2. Characterization of H3PO4-Treated Rice Husk Adsorbent and Adsorption of Copper(II) from Aqueous Solution

    PubMed Central

    Zheng, Ru; Zhao, Jiaying; Ma, Fang; Zhang, Yingchao; Meng, Qingjuan

    2014-01-01

    Rice husk, a surplus agricultural byproduct, was applied to the sorption of copper from aqueous solutions. Chemical modifications by treating rice husk with H3PO4 increased the sorption ability of rice husk for Cu(II). This work investigated the sorption characteristics for Cu(II) and examined the optimum conditions of the sorption processes. The elemental compositions of native rice husk and H3PO4-treated rice husk were determined by X-ray fluorescence (XRF) analysis. The scanning electron microscopic (SEM) analysis was carried out for structural and morphological characteristics of H3PO4-treated rice husk. The surface functional groups (i.e., carbonyl, carboxyl, and hydroxyl) of adsorbent were examined by Fourier Transform Infrared Technique (FT-IR) and contributed to the adsorption for Cu(II). Adsorption isotherm experiments were carried out at room temperature and the data obtained from batch studies fitted well with the Langmuir and Freundlich models with R2 of 0.999 and 0.9303, respectively. The maximum sorption amount was 17.0358?mg/g at a dosage of 2?g/L after 180?min. The results showed that optimum pH was attained at pH 4.0. The equilibrium data was well represented by the pseudo-second-order kinetics. The percentage removal for Cu(II) approached equilibrium at 180?min with 88.9% removal. PMID:24678507

  3. Standard thermodynamic properties of H3PO4(aq) over a wide range of temperatures and pressures.

    PubMed

    Ballerat-Busserolles, Karine; Sedlbauer, Josef; Majer, Vladimir

    2007-01-11

    The densities and heat capacities of solutions of phosphoric acid, 0.05 to 1 mol kg-1, were measured using flow vibrating tube densitometry and differential Picker-type calorimetry at temperatures up to 623 K and at pressures up to 28 MPa. The standard molar volumes and heat capacities of molecular H3PO4(aq) were obtained, via the apparent molar properties corrected for partial dissociation, by extrapolation to infinite dilution. The data on standard derivative properties were correlated simultaneously with the dissociation constants of phosphoric acid from the literature using the theoretically founded SOCW model. This made it possible to describe the standard thermodynamic properties, particularly the standard chemical potential, of both molecular and ionized phosphoric acid at temperatures up to at least 623 K and at pressures up to 200 MPa. This representation allows one to easily calculate the first-degree dissociation constant of H3PO4(aq). The performance of the SOCW model was compared with the other approaches for calculating the high-temperature dissociation constant of the phosphoric acid. Using the standard derivative properties, sensitively reflecting the interactions between the solute and the solvent, the high-temperature behavior of H3PO4(aq) is compared with that of other weak acids. PMID:17201442

  4. Crosslinking chitosan into H3PO4/HNO3-NANO2 oxidized cellulose fabrics as antibacterial-finished material.

    PubMed

    Xu, Yunhui; Qiu, Chen; Zhang, Xiaoli; Zhang, Weiwei

    2014-11-01

    The primary hydroxyl groups on C6 position in glucose units of cellulose with H3PO4/HNO3-NaNO2 mediated oxidation produced monocarboxy cellulose and binding sites, subsequent amide reaction with chitosan solution to obtain chitosan crosslinked cotton fabrics. Scanning electron microscope and FT-IR spectroscopy were used to detect the fiber morphology and chemical bonding between chitosan and oxidized cellulose, respectively. The influences of H3PO4/HNO3-NaNO2 oxidation and chitosan treatment on physical properties of cotton fabrics were examined by determining carboxyl content, weight loss and mechanical properties of fabrics, as well as chitosan content in the composite fabrics. Antibacterial performance of chitosan-cellulose fabrics against Escherichia coli and Staphylococcus aureus was evaluated. As a result, chitosan was bonded into cotton fiber via the amido bond of CN formed between amino groups of chitosan and carboxyl groups on oxidized cellulose, and these resultant chitosan-cotton fabrics showed high antimicrobial activity and excellent antibacterial washing durability. PMID:25129734

  5. Solid state 31P MAS NMR spectroscopy and conductivity measurements on NbOPO4 and H3PO4 composite materials

    NASA Astrophysics Data System (ADS)

    Risskov Sørensen, Daniel; Nielsen, Ulla Gro; Skou, Eivind M.

    2014-11-01

    A systematic study of composite powders of niobium oxide phosphate (NbOPO4) and phosphoric acid (H3PO4) has been performed in order to characterize the material's ability to perform as an electrolyte material in medium temperature fuel cells and electrolyzers. Powders of H3PO4 contents between 13.1 and 74.2 M% were produced and characterized with powder X-ray diffraction, 31P MAS NMR and impedance spectroscopy. NMR revealed that a significant degree of dehydration and vaporization of H3PO4 takes place above 200 °C, and increases with temperature. At 500 °C the NbOPO4 and H3PO4 has reacted to form niobium pyrophosphate (Nb2P4O15). Impedance spectroscopy showed an increase in conductivity with increasing acid concentration, whereas the conductivity decreased slightly with increasing temperature. The highest conductivity measured was 2.5·10-3 S/cm for a sample containing 74.2 M% of H3PO4. Lastly, it was shown that NbOPO4 has no significant conductivity of its own.

  6. Improvement in the etching performance of the acrylonitrile-butadiene-styrene resin by MnO2-H3PO4-H2SO4 colloid.

    PubMed

    Zhao, Wenxia; Ding, Jie; Wang, Zenglin

    2013-05-21

    The present study aimed to evaluate the surface etching of the acrylonitrile-butadiene-styrene (ABS) resin in the MnO2-H3PO4-H2SO4 colloid. To enhance the soluble Mn(IV) ion concentration and improve the etching performance of ABS resin, H3PO4 was added as a complexing agent into the MnO2-H2SO4 etching system. The effects of the H2SO4 concentration and etching time on the surface topography, surface roughness, adhesion strength, and the surface chemistry of the ABS substrates were investigated. The optimal oxidation potentials of MnO2 in the colloids decreased from 1.426 to 1.369 V with the addition of H3PO4. Though the etching conditions changed from 70 °C for 20 min to 60 °C for 10 min, the adhesion strength between the ABS substrates and electroless copper film increased from 1.19 to 1.33 KN/m after etching treatment. This could be attributed to the significant increase of the soluble Mn(IV) ion concentration in the MnO2-H3PO4-H2SO4 colloid. The surface chemistry results demonstrated that the oxidation reaction of -C?C- bonds in the polybutadiene phase was accelerated in the etching process by the addition of H3PO4, and the abundant -COOH and -OH groups were formed rapidly on the ABS surface with the etching treatment. These results were in agreement with the results of surface scanning electron microscopic observations and adhesion strength measurement. The results suggested that the MnO2-H3PO4-H2SO4 colloid was an effective surface etching system for the ABS surface roughness. PMID:23611532

  7. Dissolution mechanism of crystalline cellulose in H3PO4 as assessed by high-field NMR spectroscopy and fast field cycling NMR relaxometry.

    PubMed

    Conte, Pellegrino; Maccotta, Antonella; De Pasquale, Claudio; Bubici, Salvatore; Alonzo, Giuseppe

    2009-10-14

    Many processes have been proposed to produce glucose as a substrate for bacterial fermentation to obtain bioethanol. Among others, cellulose degradation appears as the most convenient way to achieve reliable amounts of glucose units. In fact, cellulose is the most widespread biopolymer, and it is considered also as a renewable resource. Due to extended intra- and interchain hydrogen bonds that provide a very efficient packing structure, however, cellulose is also a very stable polymer, the degradation of which is not easily achievable. In the past decade, researchers enhanced cellulose reactivity by increasing its solubility in many solvents, among which concentrated phosphoric acid (H(3)PO(4)) played the major role because of its low volatility and nontoxicity. In the present study, the solubilization mechanism of crystalline cellulose in H(3)PO(4) has been elucidated by using high- and low-field NMR spectroscopy. In particular, high-field NMR spectra showed formation of direct bonding between phosphoric acid and dissolved cellulose. On the other hand, molecular dynamics studies by low-field NMR with a fast field cycling (FFC) setup revealed two different H(3)PO(4) relaxing components. The first component, described by the fastest longitudinal relaxation rate (R(1)), was assigned to the H(3)PO(4) molecules bound to the biopolymer. Conversely, the second component, characterized by the slowest R(1), was attributed to the bulk solvent. The understanding of cellulose dissolution in H(3)PO(4) represents a very important issue because comprehension of chemical mechanisms is fundamental for process ameliorations to produce bioenergy from biomasses. PMID:19769370

  8. Study on the formation of dodecagonal pyramid on nitrogen polar GaN surface etched by hot H3PO4

    NASA Astrophysics Data System (ADS)

    Qi, S. L.; Chen, Z. Z.; Fang, H.; Sun, Y. J.; Sang, L. W.; Yang, X. L.; Zhao, L. B.; Tian, P. F.; Deng, J. J.; Tao, Y. B.; Yu, T. J.; Qin, Z. X.; Zhang, G. Y.

    2009-08-01

    Hot phosphor acid (H3PO4) etching is presented to form a roughened surface with dodecagonal pyramids on laser lift-off N face GaN grown by metalorganic chemical vapor deposition. A detailed analysis of time evolution of surface morphology is described as a function of etching temperature. The activation energy of the H3PO4 etching process is 1.25 eV, indicating the process is reaction-limited scheme. And it is found that the oblique angle between the facets and the base plane increases as the temperature increases. Thermodynamics and kinetics related factors of the formation mechanism of the dodecagonal pyramid are also discussed. The light output power of a vertical injection light-emitting-diode (LED) with proper roughened surface shows about 2.5 fold increase compared with that of LED without roughened surface.

  9. Dye removal of activated carbons prepared from NaOH-pretreated rice husks by low-temperature solution-processed carbonization and H3PO4 activation.

    PubMed

    Chen, Yun; Zhai, Shang-Ru; Liu, Na; Song, Yu; An, Qing-Da; Song, Xiao-Wei

    2013-09-01

    A coupling of low-temperature sulfuric acid-assisted carbonization and H3PO4 activation was employed to convert NaOH-pretreated rice husks into activated carbons with extremely high surface area (2028 m(2) g(-1)) and integrated characteristics. The influences of the activation temperature and impregnation ratio on the surface area, pore volume of activated carbons were thoroughly investigated. The morphology and surface chemistry of activated carbons were characterized using N2 sorption, FTIR, XPS, SEM, TEM, etc. The adsorption capacity of resulting carbons obtained under optimum preparation conditions was systematically evaluated using methylene blue under various simulated conditions. The adsorption process can be well described by both Langmuir isotherm model and the pseudo-second order kinetics models; and the maximum monolayer capacity of methylene blue was ca. 578 mg g(-1). PMID:23892148

  10. Reduction of interpore distance of anodized aluminum oxide nano pattern by mixed H3PO4:H2SO4 electrolyte.

    PubMed

    Song, Kwang Min; Park, Joonmo; Ryu, Sang-Wan

    2007-11-01

    A self-formed and ordered anodized aluminum oxide (AAO) nano pattern has generated considerable interest in both scientific research and commercial application. However, the interpore distance obtainable by AAO is limited by 40-500 nm depending on electrolyte and anodizing voltage. It's believed that below-30 nm AAO pattern is a key technology in the fabrication semiconductor nano structures with enhanced quantum confinement effect, so we worked on the reduction of interpore distance of AAO with a novel electrolyte. AAO nano patterns were fabricated with mixed H2SO4 and H3PO4 as an electrolyte for various voltages and temperatures. The interpore distance and pore diameter of AAO were decreased with reduced anodizing voltage. As a result, an AAO nano pattern with the interpore distance of 27 nm and the pore diameter of 7 nm was obtained. This is the smallest pattern, as long as we know, reported till now with AAO technique. The fabricated AAO pattern could be utilized for uniform and high density quantum dots with increased quantum effect. PMID:18047152

  11. Carbons prepared from coffee grounds by H3PO4 activation: characterization and adsorption of methylene blue and Nylosan Red N-2RBL.

    PubMed

    Reffas, A; Bernardet, V; David, B; Reinert, L; Lehocine, M Bencheikh; Dubois, M; Batisse, N; Duclaux, L

    2010-03-15

    Activated carbons were prepared by the pyrolysis of coffee grounds impregnated by phosphoric acid at 450 degrees C for different impregnation ratios: 30, 60, 120 and 180 wt.%. Materials were characterized for their surface chemistry by elemental analysis, "Boehm titrations", point of zero charge measurements, Infrared spectroscopy, thermogravimetric analysis (TGA); as well as for their porous and morphological structure by Scanning Electron Microscopy (SEM) and nitrogen adsorption at 77K. The impregnation ratio was found to govern the porous structure of the prepared activated carbons. Low impregnation ratios (<120 wt.%) led to essentially microporous and acidic activated carbons whereas high impregnation ratios (>120 wt.%) yielded to essentially mesoporous carbons with specific surface areas as high as 925 m(2)g(-1), pore volume as large as 0.7 cm(3)g(-1), and neutral surface. The activated carbons prepared from coffee grounds were compared to a commercial activated carbon (S(BET) approximately 1400 m(2)g(-1)) for their adsorption isotherms of methylene blue and "Nylosan Red N-2RBL", a cationic and anionic (azo) dye respectively. The mesoporous structure of the material produced at 180 wt.% H(3)PO(4) ratio was found to be appropriate for an efficient sorption of the latter azo dye. PMID:19942347

  12. Preparation and physical properties of (PVA)0.7(NaBr)0.3(H3PO4)xM solid acid membrane for phosphoric acid – Fuel cells

    PubMed Central

    Ahmad, F.; Sheha, E.

    2012-01-01

    A solid acid membranes based on poly (vinyl alcohol) (PVA), sodium bromide (NaBr) and phosphoric acid (H3PO4) were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the (PVA)0.7(NaBr)0.3(H3PO4)xM solid acid membranes where x = 0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy (SEM) studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H3PO4 concentration which it has been achieved to be of the order 4.3 × 10?3 S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the (PVA)0.7(NaBr)0.3(H3PO4)xM solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications. PMID:25685413

  13. Quantification of Competing H3PO4 Versus HPO3 + H2O Neutral Losses from Regioselective 18O-Labeled Phosphopeptides

    NASA Astrophysics Data System (ADS)

    Cui, Li; Yapici, Ipek; Borhan, Babak; Reid, Gavin E.

    2014-01-01

    Abundant neutral losses of 98 Da are often observed upon ion trap CID-MS/MS of protonated phosphopeptide ions. Two competing fragmentation pathways are involved in this process, namely, the direct loss of H3PO4 from the phosphorylated residue and the combined losses of HPO3 and H2O from the phosphorylation site and from an additional site within the peptide, respectively. These competing pathways produce product ions with different structures but the same m/z values, potentially limiting the utility of CID-MS3 for phosphorylation site localization. To quantify the relative contributions of these pathways and to determine the conditions under which each pathway predominates, we have examined the ion trap CID-MS/MS fragmentation of a series of regioselective 18O-phosphate ester labeled phosphopeptides prepared using novel solution-phase amino acid synthesis and solid-phase peptide synthesis methodologies. By comparing the intensity of the -100 Da (-H3PO3 18O) versus -98 Da (-[HPO3 + H2O]) neutral loss product ions formed upon MS/MS, quantification of the two pathways was achieved. Factors that affect the extent of formation of the competing neutral losses were investigated, with the combined loss pathway predominantly occurring under conditions of limited proton mobility, and with increased combined losses observed for phosphothreonine compared with phosphoserine-containing peptides. The combined loss pathway was found to be less dominant under ion activation conditions associated with HCD-MS/MS. Finally, the contribution of carboxylic acid functional groups and backbone amide bonds to the water loss in the combined loss fragmentation pathway was determined via methyl esterification and by examination of a phosphopeptide lacking side-chain hydroxyl groups.

  14. Review of HxPyOz-Catalyzed H + OH Recombination in Scramjet Nozzle Expansions; and Possible Phosphoric Acid Enhancement of Scramjet Flameholding, from Extinction of H3PO4 + H2 - Air Counterflow Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald

    2005-01-01

    Recent detailed articles by Twarowski indicate that small quantities of phosphorus oxides and acids in the fuel-rich combustion products of H2 + phosphine (PH3) + air should significantly catalyze H, OH and O recombination kinetics during high-speed nozzle expansions -- to reform H2O, release heat, and approach equilibrium more rapidly and closely than uncatalyzed kinetics. This paper is an initial feasibility study to determine (a) if addition of phosphoric acid vapor (H3PO4) to a H2 fuel jet -- which is much safer than using PH3 -- will allow combustion in a high-speed scramjet engine test without adverse effects on localized flameholding, and (b) if phosphorus-containing exhaust emissions are environmentally acceptable. A well-characterized axisymmetric straight-tube opposed jet burner (OJB) tool is used to evaluate H3PO4 addition effects on the air velocity extinction limit (flame strength) of a H2 versus air counterflow diffusion flame. Addition of nitric oxide (NO), also believed to promote catalytic H-atom recombination, was evaluated for comparison. Two to five mass percent H3PO4 in the H2 jet increased flame strength 4.2%, whereas airside addition decreased it 1%. Adding 5% NO to the H2 caused a 2% decrease. Products of H-atom attack on H3PO4 produced an intense green chemiluminescence near the stagnation point. The resultant exothermic production of phosphorus oxides and acids, with accelerated H-atom recombination, released sufficient heat near the stagnation point to increase flame strength. In conclusion, the addition of H3PO4 vapor (or more reactive P sources) to hydrogen in scramjet engine tests may positively affect flameholding stability in the combustor and thrust production during supersonic expansion -- a possible dual benefit with system design / performance implications. Finally, a preliminary assessment of possible environmental effects indicates that scramjet exhaust emissions should consist of phosphoric acid aerosol, with gradual conversion to phosphate aerosol. This is compared to various natural abundances and sources.

  15. Preparation and surface characterization of activated carbons from Euphorbia rigida by chemical activation with ZnCl2, K2CO3, NaOH and H3PO4

    NASA Astrophysics Data System (ADS)

    K?l?ç, Murat; Apayd?n-Varol, Esin; Pütün, Ay?e Eren

    2012-11-01

    Preparation of activated carbons from Euphorbia rigida by chemical activation with different impregnation agents and ratios was studied. ZnCl2, K2CO3, NaOH and H3PO4 were used as chemical activation agents and four impregnation ratios (25-50-75-100%) by mass were applied on biomass. Activation is applied to impregnated biomass samples at 700 °C under sweeping gas in a fixed bed reactor. For determination of chemical and physical properties of the obtained activated carbons; elemental analysis was applied to determine the elemental composition (C, H, N, O) and FT-IR spectra was used to analyze the functional groups. BET equation was used to calculate the surface areas of activated carbons. For understanding the changes in the surface structure, activated carbons were conducted to Scanning Electron Microscopy (SEM). Maximum BET surface area (2613 m2/g) was reached with 75% K2CO3 impregnated biomass sample. Experimental results showed that impregnation types and ratios have a significant effect on the pore structure of activated carbon and E. rigida seems to be an alternative precursor for commercial activated carbon production.

  16. Energy storage for a lunar base by the reversible chemical reaction: CaO+H2O reversible reaction Ca(OH)2

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Difilipo, Frank

    1990-01-01

    A thermochemical solar energy storage concept involving the reversible reaction CaO + H2O yields Ca(OH)2 is proposed as a power system element for a lunar base. The operation and components of such a system are described. The CaO/H2O system is capable of generating electric power during both the day and night. The specific energy (energy to mass ratio) of the system was estimated to be 155 W-hr/kg. Mass of the required amount of CaO is neglected since it is obtained from lunar soil. Potential technical problems, such as reactor design and lunar soil processing, are reviewed.

  17. Effect of Ca(OH)2 pretreatment on extruded rice straw anaerobic digestion.

    PubMed

    Gu, Yu; Zhang, Yalei; Zhou, Xuefei

    2015-11-01

    It has been proven that extrusion can change the structure of rice straw and increase biogas production, but the effect of a single pretreatment is limited. Ca(OH)2 pretreatment was used to enhance the enzyme hydrolysis and biogas production of extruded rice straw. After Ca(OH)2 pretreatment, the glucose and xylose conversion rates in enzymatic hydrolysis increased from 36.0% and 22.4% to 66.8% and 50.2%, respectively. The highest biogas production observed in 8% and 10% Ca(OH)2 pretreated rice straw reached 564.7mL/g VS and 574.5mL/g VS, respectively, which are 34.3% and 36.7% higher than the non-Ca(OH)2-loaded sample. The Ca(OH)2 pretreatment can effectively remove the lignin and increase the fermentable sugar content. The structural changes in the extruded rice straw have also been analyzed by XRD, FTIR, and SEM. Considering all of the results, an 8% Ca(OH)2 loading rate is the best option for the pretreatment of extruded rice straw. PMID:26231131

  18. Stress-Strain Relationship of Ca(OH)2-Activated Hwangtoh Concrete

    PubMed Central

    Mun, Ju-Hyun; Hwang, Hey-Zoo

    2014-01-01

    This study examined the stress-strain behavior of 10 calcium hydroxide (Ca(OH)2)-activated Hwangtoh concrete mixes. The volumetric ratio of the coarse aggregate (Vagg) and the water-to-binder (W/B) ratio were selected as the main test variables. Two W/B ratios (25% and 40%) were used and the value of Vagg varied between 0% and 40.0%, and 0% and 46.5% for W/B ratios of 25% and 40%, respectively. The test results demonstrated that the slope of the ascending branch of the stress-strain curve of Ca(OH)2-activated Hwangtoh concrete was smaller, and it displayed a steeper drop in stress in the descending branch, compared with those of ordinary Portland cement (OPC) concrete with the same compressive strength. This trend was more pronounced with the increase in the W/B ratio and decrease in Vagg. Based on the experimental observations, a simple and rational stress-strain model was established mathematically. Furthermore, the modulus of elasticity and strain at peak stress of the Ca(OH)2-activated Hwangtoh concrete were formulated as a function of its compressive strength and Vagg. The proposed stress-strain model predicted the actual behavior accurately, whereas the previous models formulated using OPC concrete data were limited in their applicability to Ca(OH)2-activated Hwangtoh concrete. PMID:25147869

  19. Nanostructure and irreversible colloidal behavior of Ca(OH)2: implications in cultural heritage conservation.

    PubMed

    Rodriguez-Navarro, C; Ruiz-Agudo, E; Ortega-Huertas, M; Hansen, E

    2005-11-22

    Although Ca(OH)2 is one of the oldest art and building material used by mankind, little is known about its nanostructural and colloidal characteristics that play a crucial role in its ultimate performance as a binder in lime mortars and plasters. In particular, it is unknown why hydrated lime putty behaves as an irreversible colloid once dried. Such effect dramatically affects the reactivity and rheology of hydrated lime dispersions. Here we show that the irreversible colloidal behavior of Ca(OH)2 dispersions is the result of an oriented aggregation mechanism triggered by drying. Kinetic stability and particle size distribution analysis of oven-dried slaked lime or commercial dry hydrate dispersions exhibit a significant increase in settling speed and particle (cluster) size in comparison to slaked lime putty that has never been dried. Drying-related particle aggregation also leads to a significant reduction in surface area. Electron microscopy analyses show porous, randomly oriented, micron-sized clusters that are dominant in the dispersions both before and after drying. However, oriented aggregation of the primary Ca(OH)2 nanocrystals (approximately 60 nm in size) is also observed. Oriented aggregation occurs both before and during drying, and although limited before drying, it is extensive during drying. Nanocrystals self-assemble in a crystallographically oriented manner either along the 100 or equivalent 110 directions, or along the Ca(OH)2 basal planes, i.e., along [001]. While random aggregation appears to be reversible, oriented aggregation is not. The strong coherent bonding among oriented nanoparticles prevents disaggregation upon redispersion in water. The observed irreversible colloidal behavior associated with drying of Ca(OH)2 dispersions has important implications in heritage conservation, particularly considering that nowadays hydrated lime is often the preferred alternative to portland cement in architectural heritage conservation. Finally, our study demonstrates that, fortuitously, hydrated lime could be one of the first nanomaterials used by mankind. PMID:16285758

  20. Stacking Faults in Ca(OH)2 Produced by Vapour Phase Hydration

    NASA Astrophysics Data System (ADS)

    Spinolo, G.; Tamburini, U. Anselmi

    1985-01-01

    The diffraction profiles of a thin single crystal with stacking faults were calculated with the theory of diffraction of a one-dimensionally disordered crystal (Kakinoki, Komura, Allegra) by including the effect of crystallite thickness. The results hold for generalized close packed structures. An application to calcium hydroxide is discussed: the stacking faults significantly contribute to the disorder of poorly crystalline forms of Ca(OH)2 produced by reaction of calcium oxide with water vapour at room temperature.

  1. THE EFFECT OF STORAGE CONDITIONS ON HANDLING AND SO2 REACTIVITY OF CA(OH)2-BASED SORBENTS

    EPA Science Inventory

    The article gives results of an investigation of the effect of relative humidity (RH), time, and aeration during calcium hydroxide -- Ca(OH)2--storage for its effect on sorbent handling and reactivity with sulfur dioxide (SO2). nvestigated was the effect of sorbent storage condit...

  2. Dissolution and carbonation of Portlandite [Ca(OH)2] single crystals.

    PubMed

    Ruiz-Agudo, Encarnación; Kud?acz, Krzysztof; Putnis, Christine V; Putnis, Andrew; Rodriguez-Navarro, Carlos

    2013-10-01

    The dissolution and carbonation of portlandite (Ca(OH)2) single crystals was studied by a combination of in situ Atomic Force Microscopy, Scanning Electron Microscopy, and two-dimensional X-ray diffraction. The dissolution of portlandite {0001} surfaces in water proceeds by the formation and expansion of pseudohexagonal etch pits, with edges parallel to ?100? directions. Etch pits on {010} surfaces are elongated along ?001?, with edges parallel to ?101?. The interaction between carbonate-bearing solutions and portlandite results in the dissolution of the substrate coupled with the precipitation of thick islands of CaCO3 that appear oriented on the portlandite substrate. Ex situ carbonation of portlandite in contact with air results in the formation of pseudomorphs that fully preserve the external shape of the original portlandite single crystals. Our observations suggest that portlandite carbonation in contact with air and carbonate-bearing solutions occurs by a similar mechanism, i.e. coupled dissolution-precipitation. Calcite grows epitaxially on {0001} portlandite surfaces with the following orientation: ?001?Cc? ?001?Port. Apparently, no porosity is generated during the reaction, which progresses through the formation of fractures. Our results are of relevance to many processes in which the carbonation of portlandite takes place, such as CO2 capture and storage or the carbonation of cementitious materials. PMID:23915181

  3. Static compression of Ca(OH)2 at room temperature - Observations of amorphization and equation of state measurements to 10.7 GPa

    NASA Technical Reports Server (NTRS)

    Meade, Charles; Jeanloz, Raymond

    1990-01-01

    X-ray diffraction measurements are reported for Ca(OH)2 portlandite as it is compressed to 37.6 GPa in the diamond cell at room temperature. Between 10.7 and 15.4 GPa crystalline Ca(OH)2 transforms to a glass, and on decompression the glass recrystallizes between 3.6 and 5.1 GPa. Below pressures of 10.7 GPa the elastic compression of crystalline Ca(OH)2 was measured. A finite strain analysis of these data shows that the isothermal bulk modulus and its pressure derivative are 37.8 + or - 1.8 GPa and 5.2 + or - 0.7 at zero pressure. The change in the unit cell dimensions indicates that the linear incompressibilities of Ca(OH)2 differ by a factor of three.

  4. In vivo behaviors of Ca(OH)2 activated nano SiO2 (nCa/nSi=3) cement in rabbit model.

    PubMed

    Lin, Qing; Zhang, Xiaojuan; Lu, Chunhua; Lan, Xianghui; Hou, Guihua; Xu, Zhongzi

    2016-01-01

    In vivo behaviors of Ca(OH)2 activated nano SiO2 (nCa/nSi=3, TCS) cement were investigated in the rabbit femoral defects using the poly(methyl methacrylate) (PMMA) as control. The deposited apatite and CaCO3 layers round TCS paste surfaces were completely used to construct the new bone tissue. TCS paste could stimulate the formation of new bone tissue in marrow tissue. The osteostimulation was mainly attributed to the proliferation and differentiation effects of Ca and Si ions released from TCS paste on the osteoprogenitor cells. However, Calcium-Silicate-Hydrate (C-S-H) gel in TCS paste was harder to degradate than Ca(OH)2. TCS paste kept the original shape during implantation, and could not provide the pores or spaces for further formation of bone tissue. Osteolytic defects induced by wear particles from TCS paste surface could not be completely avoided, because of the interfacial strain and the extensive micromotion between TCS paste surface and new bone tissue. Overall, our results indicated that Ca(OH)2 activated nano SiO2 cement was bioactivity and osteostimulation. The further improvements of Ca(OH)2 activated nano SiO2 cement should be done by achieving a balance between biological properties and mechanical performances. PMID:26478371

  5. Combined modification of fly ash with Ca(OH)2/Na2FeO4 and its adsorption of Methyl orange

    NASA Astrophysics Data System (ADS)

    Gao, Mengfan; Ma, Qingliang; Lin, Qingwen; Chang, Jiali; Bao, Weiren; Ma, Hongzhu

    2015-12-01

    Fly ash resulted during the coal burning for energy production is a waste that can be used in wastewater treatment for removal of dyes. Fly ash (FA) modified by Ca(OH)2/Na2FeO4 was used as adsorbent for methyl orange (MO) wastewater treatment. The effect of parameters (contact time, dosage of adsorbent, initial concentration of MO) on MO adsorption are optimized. At the optimized conditions: 4.00 × 10-3 g/mL of adsorbent, 50 mg/L MO, 40 min, the raw pH value (pH = 10), 99.2% color removal was achieved at room temperature. The thermodynamic and kinetic of the adsorption processes were also studied, and further discussed correlated with the surface structure (XRD) and morphology (SEM, BET). The results indicate that the Ca(OH)2/Na2FeO4 modified FA can be used as an efficient and low cost adsorbent for removal of dyes.

  6. Grain-boundary migration in KCl bicrystals

    NASA Technical Reports Server (NTRS)

    Gibbon, C. F.

    1968-01-01

    Boundary migration in melt-grown bicrystals of KCl containing pure twist boundaries was investigated. The experiments involve the use of bicrystal specimens in the shape of right-triangular prisms with the boundary parallel to one side.

  7. Production and characterisation of hydroxyapatite/multi-walled carbon nanotube composites

    E-print Network

    White, Ashley Ann

    2010-01-12

    of mechanical properties, and 4) assessment of biological response to in vitro cell culture. HA was synthesised by a precipitation reaction between Ca(OH)2 and H 3PO4, and multi-walled CNTs were produced by chemical vapour deposition. Composites were...

  8. Electrolytic reduction of Tl + ions in KCl crystals

    NASA Astrophysics Data System (ADS)

    Polosan, Silviu; Tsuboi, Taiju; Apostol, Elena; Topa, Vladimir

    2007-09-01

    Electrolytic coloration has been made for KCl crystals doped with Tl+ ions and doped with Tl+ and Ca2+ ions. Intensity decrease of the Tl+ absorption bands is observed in the two colored crystals, while several new absorption and emission bands are observed. They are attributed to Tl- ions which were converted from Tl+ ions by electron injection during electrolytic coloration. Different absorption and emission bands are observed for KCl:Tl and KCl:Tl + Ca crystals. Sharp absorption band appears at 285 nm in the colored KCl:Tl and at 400 and 503 nm in the colored KCl:Tl + Ca. Infrared emission bands are observed at 1470, 1600 and 2185 nm in colored KCl:Tl, while at 1630 and 1900 nm in colored KCl:Tl + Ca. It is suggested that the absorption and emission bands in KCl:Tl + Ca are due to Tl- ions perturbed by Ca2+ or vacancy at the nearest neighbor.

  9. Determination of the adsorption capacity of activated carbon made from coffee grounds by chemical activation with ZnCl2 and H3PO4.

    PubMed

    Namane, A; Mekarzia, A; Benrachedi, K; Belhaneche-Bensemra, N; Hellal, A

    2005-03-17

    In order to evaluate the adsorptive capacities of granular activated carbon produced from coffee grounds by chemical activation, the adsorption of different phenols and acid and basic dyes, has been carried out. The comparison with a commercial activated carbon has been made. Adsorption isotherms of phenols and dyes (acid and basic) onto produced and commercial granular activated carbons were experimentally determined by batch tests. Both Freundlich and Langmuir models are well suited to fit the adsorption isotherm data. As a result, the coffee grounds based activated carbon may be promising for phenol and dye removal from aqueous streams. PMID:15752865

  10. Preferential interactions in aqueous solutions of urea and KCl.

    PubMed

    Hong, Jiang; Capp, Michael W; Anderson, Charles F; Record, M Thomas

    2003-09-01

    A quantitative characterization of the thermodynamic effects due to interactions of salt ions and urea in aqueous solution is needed for rigorous analyses of the effects of changing urea concentration on biopolymer processes in solutions that also contain salt. Therefore, we investigate preferential interactions in aqueous solutions containing KCl and urea by using vapor pressure osmometry (VPO) to measure osmolality as a function of the molality of urea (component 3) over the range 0.09KCl (component 2) (m(2)=0.212 and 0.427 m). With this experimental input and corresponding VPO measurements on solutions that contain only urea or KCl, we evaluate approximately the chemical potential derivative micro(23)=( partial differential micro(KCl)/ partial differential m(urea))(T,P,m(KCl))=( partial differential micro(urea)/ partial differential m(KCl))(T,P,m(urea))= micro(32) and hence the preferential interaction coefficients Gammamicro(3) and Gammamicro(1),micro(3). These results show that for water-KCl-urea solutions neither of these coefficients is determined primarily by contributions from thermodynamic nonideality to micro(23). In aqueous solutions containing a biopolymer and a small solute, the contribution of ideal mixing entropy to micro(23) is negligible in comparison with the experimental uncertainty, whereas in KCl-urea solutions the contribution due to ideal mixing entropy accounts for at least half of the magnitude of micro(23). For comparison, we analyze literature data for NaCl-urea interactions and find again that nonideality makes a smaller contribution to micro(23) than does ideal mixing entropy. In contrast, for aqueous solutions of urea and the protein bovine serum albumin, the experimentally determined contribution of nonideality to micro(23) exceeds the contribution of ideal mixing by a factor of approximately 2 x 10(2). PMID:14499915

  11. Effect of KCl addition method on the Pt/KL catalyst for the aromatization of hexane

    SciTech Connect

    Dai, Lian-Xin; Sakashita, Haru; Tatsumi, Takashi )

    1994-05-01

    The influence of the method for loading platinum precursor and adding KCl, KCl loading content, calcination temperature, KCl addition procedure, various additives, and water washing on the activity and selectivity of Pt/KL catalysts for hexane reforming reaction has been investigated. The catalyst preparation methods involve ion exchange (IE), incipient wetness impregnation (IWI), and coimpregnation with KCl (IWI-KCl). The Pt/KL catalysts prepared by ion exchange with [Pt(NH[sub 3])[sub 4

  12. Pressure leaching of leucoxene concentrate using Ca(OH)2

    NASA Astrophysics Data System (ADS)

    Zabolotskaya, Yu. V.; Sadykhov, G. B.; Goncharenko, T. V.; Olyunina, T. V.; Anisonyan, K. G.; Tagirov, R. K.

    2011-11-01

    The results of studying the desiliconization of a leucoxene concentrate using burned lime as a reagent in the presence of NaOH as a catalyst are presented. This process is based on the selective interaction of CaO with the fine silica present in leucoxene grains, which results in the formation of CaSiO3 at high temperatures and pressures (autoclave process). Experiments are performed on the initial leucoxene concentrate and the products of its beneficiation after magnetizing roasting.

  13. Luminescence studies on gamma irradiated KCl: Ce3+ crystals

    NASA Astrophysics Data System (ADS)

    Bangaru, S.; Muralidharan, G.

    2012-06-01

    This paper reports thermoluminescence(TL), optical absorption and TL emission studies that are made on Ce3+ doped KCl single crystals irradiated at room temperature. The glow curve and optical absorption studies indicate the participation of Ce3+ ions in the TL process. The TL study suggests the presence of low concentration of Ce3+ ions which reduces the TL efficiency with respect to pure KCl samples. On F bleaching ? irradiated crystals Z1 centers are observed. A broader and strongly intense violet blue emission at 290, 370, 423 and 488 nm has been observed with 240 nm excitation. This emission has been attributed due to the transition from 5d(2D) excited energy level to the 4f1 ground stable energy level (2F5/2 and 3F7/2) of Ce3+ doped KCl crystals.

  14. Upper stratospheric photolysis of NaCl and KCl

    PubMed Central

    Rowland, F. Sherwood; Rogers, Patricia J.

    1982-01-01

    Sodium chloride has been postulated to be formed in the stratosphere by the reaction of NaOH with HCl, and an analogous reaction should occur also for KOH, with the formation of KCl. Photodissociation rates have been calculated for both NaCl and KCl using the published ultraviolet absorption cross sections below 300 nm. Both molecules absorb strongly and have photodissociation lifetimes of only a few minutes in the upper stratosphere. Neither molecule is an effective sink for chlorine above an altitude of about 35 km. PMID:16593182

  15. Substituting KCl for NaCl in fresh Queso Fresco

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing the sodium level in cheese is challenging when a signature salty flavor is expected, such as in high-moisture Queso Fresco (QF). Fresh starter-free QF was fine milled and dry salted at different levels of NaCl and KCl to obtain total salt levels of 1.5 to 2.0%. The treatments contained 1....

  16. VAPORIZATION THERMODYNAMICS OF KCl. COMBINING VAPOR PRESSURE AND GRAVIMETRIC DATA

    E-print Network

    Rudnyi, Evgenii B.

    1 VAPORIZATION THERMODYNAMICS OF KCl. COMBINING VAPOR PRESSURE AND GRAVIMETRIC DATA Rudnyi E of thermodynamic properties of the vapor and the vaporization process, coupling pressure measurements. INTRODUCTION The vapor pressure of a substance is an important system property in many applications. Its value

  17. Effects of KCl substitution on textural properties of Queso Fresco

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Partial substitution of KCl for NaCl has been attempted in some common cheese varieties because of restrictions on sodium in the diets of some consumers. The changes in texture of Queso Fresco, a popular Hispanic cheese, were monitored during refrigerated storage after replacing some of the NaCl wi...

  18. Structure of CO2 monolayer on KCl(1 0 0)

    NASA Astrophysics Data System (ADS)

    Wu, Taiquan; Cao, Dan; Wang, Xinyan; Jiao, Zhiwei; Jiang, Zhouting; Chen, Miaogen; Luo, Honglei; Zhu, Ping

    2015-06-01

    The first-principle technique has been employed to determine the structure of carbon dioxide (CO2) dimers, molecular chains, monolayers and the CO2/KCl(1 0 0) system. Their potential structures have been proposed. CASTEP calculation shows that CO2 molecular chains and monolayers based on two stable dimers by the electric interaction are all self-assembly system. At the coverage of 1.00 ML, two stable structures have been proposed when CO2 monolayer on the KCl(1 0 0) surface. The best one is the monolayer adsorbed on the surface with the C atom in the bridge site, the angle ? between the molecular bond and the surface is 24°. The better one is the monolayer horizontally adsorbed on the surface with the C atom in the top-Cl site. The structural parameters in the adsorption system are similar to those in the monolayer.

  19. The surface charge of KCl as influenced by crystal lattice defects

    SciTech Connect

    Yalamanchili, M.R.; Miller, J.D. . Dept. of Metallurgical Engineering)

    1994-03-01

    Recently, nonequilibrium electrokinetic measurements using laser-Doppler electrophoresis were reported for alkali halides and the sign of their surface charge was thus determined. These results are generally as expected from simplified lattice ion hydration theory with KCl, under normal circumstances, being the most significant exception. In this regard, lattice defects (F centers and oxygen imperfections) have been found to influence the surface charge of KCl and its electrophoretic mobility. In particular, the presence of oxygen defect states in the crystal lattice has been found to be responsible for KCl's unexpected behavior. The concentration of oxygen defect states in KCl, as characterized by UV/Vis absorption, was varied in order to study their influence on the electrokinetic behavior and subsequently on the flotation response of KCl. At low oxygen contents (<60 ppm) KCl is positively charged as expected from lattice ion hydration theory. However, typically, KCl contains substantial oxygen (>300 ppm), sufficient to impart a negative surface charge and this accounts for the selective flotation of KCl from NaCl by heterocoagulation with oppositely charged alkyl amine hydrochloride collector colloids.

  20. Concentration and precipitation of NaCl and KCl from salt cake leach solutions by electrodialysis

    SciTech Connect

    Sreenivasarao, K; Patsiogiannis, F.; Hryn, J.N.

    1997-02-09

    Electrodialysis was investigated for cost-effective recovery of salt from salt cake leach solutions. (Salt cake is a waste stream generated by the aluminum industry during treatment of aluminum drosses and scrap.) We used a pilot-scale electrodialysis stack of 5 membrane pairs, each with an effective area of 0.02 m{sup 2}. The diluate stream contained synthetic NaCl, KCl,mixtures of NaCl and KCl, and actual salt cake leach solutions (mainly NaCl and KCl, with small amounts of MgCl{sub 2}). We concentrated and precipitated NaCl and KCl salts from the concentrate steam when the initial diluate stream concentration was 21.5 to 28.8 wt% NaCl and KCl. We found that water transferring through the membranes was a significant factor in overall efficiency of salt recovery by electrodialysis.

  1. Radiation effects on beta /10.6/ of pure and europium doped KCl

    NASA Technical Reports Server (NTRS)

    Grimes, H. H.; Maisel, J. E.; Hartford, R. H.

    1975-01-01

    Changes in the optical absorption coefficient as the result of X-ray and electron bombardment of pure monocrystalline and polycrystalline KCl and of divalent europium doped polycrystalline KCl were determined. A constant heat flow calorimetric method was used to measure the optical absorption coefficients. Both 300 kV X-ray irradiation and 2 MeV electron irradiation produced increases in the optical absorption coefficient at room temperature. X-ray irradiation produced more significant changes in pure monocrystalline KCl than equivalent amounts of electron irradiation. Electron irradiation of pure and Eu-doped polycrystalline KCl produced increases in the absorption by as much as a factor of 20 over untreated material. Bleaching of the electron-irradiated doped KCl with 649 millimicron light produced a further increase.

  2. High temperature creep behavior and substructure in KCl-KBr solid solution alloys

    SciTech Connect

    Duong, H.; Wolfenstine, J. . Dept. of Mechanical and Aerospace Engineering); Beeman, M. )

    1994-03-01

    The creep behavior and dislocation substructure of pure KCl, pure KBr and two KCl-KBr solid solution alloys was investigated at 700 C. The reduced primary stage compared to that for the pure materials, stress exponent close to 3, nature of the creep transient after a stress reduction for the KCl-KBr alloys is in good agreement with creep behavior observed in class 1 metallic, KCl-NaCl and KCl-RbCl solid solution alloys, where the creep rate is controlled by a viscous dislocation glide process. The creep behavior of the KCl-KBr solid solution alloys is in agreement with the prediction of the glide-climb criterion for solid solution alloys developed by Mohamed and Langdon. The dislocation substructure of KCl-KBr solid solution alloys consisted of well-developed subgrains whose size was larger than that for the pure materials at an equivalent value of normalized stress and varied inversely with applied stress. 66 refs., 10 figs.

  3. H2O activity in concentrated KCl and KCl-NaCl solutions at high temperatures and pressures measured by the brucite-periclase equilibrium

    NASA Astrophysics Data System (ADS)

    Aranovich, L. Y.; Newton, R. C.

    H2O activities in supercritical fluids in the system KCl-H2O-(MgO) were measured at pressures of 1, 2, 4, 7, 10 and 15 kbar by numerous reversals of vapor compositions in equilibrium with brucite and periclase. Measurements spanned the range 550-900°C. A change of state of solute KCl occurs as pressures increase above 2kbar, by which H2O activity becomes very low and, at pressures of 4kbar and above, nearly coincident with the square of the mole fraction (xH2O). The effect undoubtedly results primarily from ionic dissociation as H2O density (?H2O) approaches 1gm/cm3, and is more pronounced than in the NaCl-H2O system at the same P-T-X conditions. Six values of solute KCl activity were yielded by terminal points of the isobaric brucite-periclase T-xH2O curves where sylvite saturation occurs. The H2O mole fraction of the isobaric invariant assemblage brucite-periclase-sylvite-fluid is near 0.52 at all pressures, and the corresponding temperatures span only 100°C between 1 and 15kbar. This remarkable convergence of the isobaric equilibrium curves reflects the great influence of pressure on lowering of both KCl and H2O activities. The H2O and KCl activities can be expressed by the formulas: aH2O=?H2O[xH2O+(1+(1+?)xKCl)], and aKCL=?KCl[(1+?)xKCl/(xH2O+(1+?)xKCl)](1+?), where ? is a degree of dissociation parameter which increases from zero at the lowest pressures to near one at high pressures and the ?'s are activity coefficients based on an empirical regular solution parameter W: ln ?i=(1-xi)2W. Least squares fitting of our H2O and KCl activity data evaluates the parameters: ?=exp(4.166 -2.709/?H2O) - 212.1P/T, and W=(-589.6-23.10P) /T, with ?H2O in gm/cm3, P in kbar and T in K. The standard deviation from the measured activities is only +/-0.014. The equations define isobaric liquidus curves, which are in perfect agreement with previous DTA liquidus measurements at 0.5-2kbar, but which depart progressively from their extrapolation to higher pressures because of the pressure-induced dissociation effect. The great similarity of the NaCl-H2O and KCl-H2O systems suggests that H2O activities in the ternary NaCl-KCl-H2O system can be described with reasonable accuracy by assuming proportionality between the binary systems. This assumption was verified by a few reconnaissance measurements at 10kbar of the brucite-periclase equilibrium with a Na/(Na+K) ratio of 0.5 and of the saturation temperature for Na/(Na+K) of 0.35 and 0.50. At that pressure the brucite-periclase curves reach a lowest xH2O of 0.45 and a temperature of 587°C before salt saturation occurs, values considerably lower than in either binary. This double-salt eutectic effect may have a significant application to natural polyionic hypersaline solutions in the deep crust and upper mantle in that higher solute concentrations and very low H2O activities may be realized in complex solutions before salt saturation occurs. Concentrated salt solutions seem, from this standpoint, and also because of high mechanical mobility and alkali-exchanging potential, feasible as metasomatic fluids for a variety of deep-crust and upper mantle processes.

  4. The clinical significance of K-Cl cotransport activity in red cells of patients with HbSC disease.

    PubMed

    Rees, David C; Thein, Swee Lay; Osei, Anna; Drasar, Emma; Tewari, Sanjay; Hannemann, Anke; Gibson, John S

    2015-05-01

    HbSC disease is the second commonest form of sickle cell disease, with poorly understood pathophysiology and few treatments. We studied the role of K-Cl cotransport activity in determining clinical and laboratory features, and investigated its potential role as a biomarker. Samples were collected from 110 patients with HbSC disease and 41 with sickle cell anemia (HbSS). K-Cl cotransport activity was measured in the oxygenated (K-Cl cotransport(100)) and deoxygenated (K-Cl cotransport(0)) states, using radioactive tracer studies. K-Cl cotransport activity was high in HbSC and decreased significantly on deoxygenation. K-Cl cotransport activity correlated significantly and positively with the formation of sickle cells. On multiple regression analysis, K-Cl cotransport increased significantly and independently with increasing reticulocyte count and age. K-Cl cotransport activity was increased in patients who attended hospital with acute pain in 2011 compared to those who did not (K-Cl cotransport(100): mean 3.87 versus 3.20, P=0.009, independent samples T-test; K-Cl cotransport(0): mean 0.96 versus 0.68, P=0.037). On logistic regression only K-Cl cotransport was associated with hospital attendance. Increased K-Cl cotransport activity was associated with the presence of retinopathy, but this effect was confounded by age. This study links variability in a fundamental aspect of cellular pathology with a clinical outcome, suggesting that K-Cl cotransport is central to the pathology of HbSC disease. Increased K-Cl cotransport activity is associated with increasing age, which may be of pathophysiological significance. Effective inhibition of K-Cl cotransport activity is likely to be of therapeutic benefit. PMID:25749827

  5. Polarized emission from KCl:Eu2+ single crystals

    NASA Astrophysics Data System (ADS)

    Kang, Jun-Gill; Sohn, Youngku; Nah, Min-Kook; Kim, Youn-Doo; Ogryzlo, Elmer A.

    2000-04-01

    The polarization emission spectrum and the angular dependence of polarization ratio of the blue emission from KCl:Eu2+ were investigated at 78.8 K. The polarized emission at 420 nm consisted of several components. The angular dependence of polarization ratio of each component is proportional to sin(2icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> ) or -cos(2icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> ), when the exciting light is polarized at icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> with respect to the z -axis for the [100]-[010] optical arrangement. The relaxed excited states (RESs) of Eu2+ responsible for the 420 nm emission are presented in terms of the adiabatic potential energy surface (APES), taking into account the Jahn-Teller effect (JTE) coupling to the Eg mode and the spin-orbit (SO) interaction. The charge-compensating cation vacancy (CCV, Vc - ) also causes an additive perturbation.

  6. Dissolution rates of NaCl and KCl in aqueous solution

    NASA Astrophysics Data System (ADS)

    Simon, B.

    1981-04-01

    Dissolution rates of compressed powders of NaCl and KCl with a stirring rate of 200 rpm are: V NaCl= 0.55X10 -3-0.55X10 -3( {C}/{C s}) cm/s and V KCl= 0.73X10 -3-0.73X10 -3( {C}/{C s}) cm/s, where C and Cs are in g/cm 3. Only the model of Berthoud is valid, where the surface dissolution kinetics is given by V= K0( Cs- Ci). Dissolution of NaCl in a solution containing KCl can induce a "salting out" effect for KCl, and vice-versa. The dissolution rate of NaCl is reduced by addition of CdCl 2: the poisoning of the surface is greater at lower dissolution rate.

  7. Template-Directed Directionally Solidified 3D Mesostructured AgCl-KCl Eutectic Photonic Crystals.

    PubMed

    Kim, Jinwoo; Aagesen, Larry K; Choi, Jun Hee; Choi, Jaewon; Kim, Ha Seong; Liu, Jinyun; Cho, Chae-Ryong; Kang, Jin Gu; Ramazani, Ali; Thornton, Katsuyo; Braun, Paul V

    2015-08-19

    3D mesostructured AgCl-KCl photonic crystals emerge from colloidal templating of eutectic solidification. Solvent removal of the KCl phase results in a mesostructured AgCl inverse opal. The 3D-template-induced confinement leads to the emergence of a complex microstructure. The 3D mesostructured eutectic photonic crystals have a large stop band ranging from the near-infrared to the visible tuned by the processing. PMID:26177830

  8. Solubility of NaCl and KCl in aqueous HCl from 20 to 85°C

    USGS Publications Warehouse

    Potter, Robert W., II; Clynne, Michael A.

    1980-01-01

    The solubilities of NaCl and KCl in aqueous HCl solutions were determined from 20 to 85°C at concentrations ranging from 0 to 20 g of HCl/100 g of solution. Equations are given that describe the solubilities over the range of conditions studied. For NaCl and KCl respectively measured solubilities show an average deviation from these equations of ??0.10 and ??0.08 g/100 g of saturated solution.

  9. Spectroelectrochemical Study of Neptunium in Molten LiCl-KCl Eutectic

    NASA Astrophysics Data System (ADS)

    Polovov, Ilya B.; Sharrad, Clint A.; May, Iain; Volkovich, Vladimir A.; Vasin, Boris D.

    2007-12-01

    Neptunium behaviour in an LiCl-KCl eutectic melt at 723 K was studied using spectroelectrochemistry. Cathodic reduction of neptunium(IV)-containing melts led to the formation of Np(III) ions and then neptunium metal. Electronic absorption spectra of Np(IV) and Np(III) chloro species in LiCl-KCl melt were recorded and resolved into individual Gaussian bands. The nature of neptunium complex ions in the melt is discussed.

  10. Current-induced composition gradients in molten LiCl-KCl battery electrolytes

    SciTech Connect

    Braustein, J.; Cantor, S.; Vallet, C.E.

    1981-01-01

    Current induced composition gradients were demonstrated in molten LiCl-KCl eutectic mixture, the electrolyte of a LiAl/LiCl-KCl/FeS/sub x/ battery. Analysis of composition profiles in quenched samples was by atomic absorption spectroscopy (AA), which gave good precision, and by x-ray fluorescence spectroscopy in a scanning electron microscope (SEM/EDX), which gave good distance resolution. 5 refs.

  11. Radiation effects on beta 10.6 of pure and europium doped KCl

    NASA Technical Reports Server (NTRS)

    Grimes, H. H.; Maisel, J. E.; Hartford, R. H.

    1975-01-01

    Changes in the optical absorption coefficient as a result of X-ray and electron bombardment of pure KCl (monocrystalline and polycrystalline), and divalent europium doped polycrystalline KCl were determined. The optical absorption coefficients were measured by a constant heat flow calorimetric method. Both 300 KV X-irradiation and 2 MeV electron irradiation produced significant increases in beta 10.6, measured at room temperature. The X-irradiation of pure moncrystalline KCl increased beta 10.6 by 0.005/cm for a 113 MR dose. For an equivalent dose, 2 MeV electrons were found less efficient in changing beta 10.6. However, electron irradiation of pure and Eu-doped polycrystalline KCl produced marked increases in adsorption. Beta increased to over 0.25/cm in Eu-doped material for a 30 x 10 to the 14th power electrons/sq cm dose, a factor of 20 increase over unirradiated material. Moreover, bleaching the electron irradiated doped KCl with 649 m light produced and additional factor of 1.5 increase. These findings will be discussed in light of known defect-center properties in KCl.

  12. Influence of partial replacement of NaCl with KCl on profiles of volatile compounds in dry-cured bacon during processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the influence of partial substitution of NaCl with KCl on the formation of volatile compounds in bacons during processing using a purge and trap dynamic headspace GC/MS system. Three substitutions were 0% KCl (I), 40% KCl (II), and 70% KCl (III). The profiles of the volatile ...

  13. Calculation of the standard partial molal thermodynamic properties of KCl{sup 0} and activity coefficients of aqueous KCl at temperatures and pressures to 1000{degree}C and 5 kbar

    SciTech Connect

    Pokrovskii, V.A.; Helgeson, H.C.

    1997-06-01

    Regression of experimental activity coefficient and dissociation constant data reported in the literature with the Hueckel and Setchenow equations and the revised HKF equations of state generated parameters and thermodynamic properties of dissociated KCl and KCl{sup 0} at 25{degrees}C and bar that can be used to calculate the standard partial molal thermodynamic properties of KCl{sup 0} and the activity coefficients of KCl at temperatures and pressures to 1000{degrees}C and 5 kbar. 46 refs., 6 figs., 4 tabs.

  14. KCl ultra-thin films with polar and non-polar surfaces grown on Si(111)7 × 7

    PubMed Central

    Beinik, Igor; Barth, Clemens; Hanbücken, Margrit; Masson, Laurence

    2015-01-01

    The growth of ultra-thin KCl films on the Si(111)7 × 7 reconstructed surface has been investigated as a function of KCl coverage and substrate temperature. The structure and morphology of the films were characterized by means of scanning tunneling microscopy (STM) under ultra-high vacuum (UHV) conditions. Detailed analysis of the atomically resolved STM images of islands grown at room and high temperatures (400?K–430?K) revealed the presence of KCl(001) and KCl(111) islands with the ratio between both structures depending on the growth temperature. At room temperature, the growth of the first layer, which covers the initial Si(111)7 × 7 surface, contains double/triple atomic layers of KCl(001) with a small fraction of KCl(111) islands. The high temperature growth promotes the appearance of large KCl(111) areas, which are built up by three atomic layers. At room and high temperatures, flat and atomically well-defined ultra-thin KCl films can be grown on the Si(111)7 × 7 substrate. The formation of the above mentioned (111) polar films is interpreted as a result of the thermally activated dissociative adsorption of KCl molecules on Si(111)7 × 7, which produces an excess of potassium on the Si surface. PMID:25650038

  15. Improved and excellent humidity sensitivities based on KCl-doped TiO2 electrospun nanofibers

    NASA Astrophysics Data System (ADS)

    Qi, Qi; Zhang, Tong; Wang, Lijie

    2008-07-01

    Pure and KCl-doped TiO2 nanofibers have been synthesized by electrospinning and calcination technique. The measurement results by the sensors fabricated from these fibers at the working electrodes show that KCl-doped TiO2 nanofibers hold the improved humidity sensing properties with the resistance varying more than four orders of magnitude in the range of 11%-95% relative humidity, while the resistance of pure TiO2 nanofibers changes only about two orders of magnitude. An ion-controlled model has been established to explain the results further. Additionally, excellent sensing characteristics (rapid response and recovery behavior and good stability) have been also found based on KCl-doped TiO2 nanofibers, which endows our product with the potentials for humidity sensors.

  16. GM Media-Sept 21, 2007 PBS, NH4Cl and KCl

    E-print Network

    HPO4 4.576 141.99 32.23 9.152 141.99 64.455243 18.304 141.99 128.91049 KCl 0.13 74.5 1.74 0.26 74.5 3.08 137.99 71.077614 Na2HPO4 45.76 141.99 32.227622 91.52 141.99 64.455243 183.04 141.99 128.91049 KCl 1

  17. Comparison of discharge power in dielectric barrier discharge (DBD) with stainless steel and KCl liquid electrode

    NASA Astrophysics Data System (ADS)

    Traikool, T.; Poolyarat, N.; Onjun, T.

    2015-05-01

    A Dielectric Barrier Discharge (DBD) device is developed to generate cold atmospheric plasma. Two different materials used as a top electrode: stainless steel and KCl liquid are considered. The bottom electrode is stainless steel for both cases. The gap of this DBD can be varied up to 3 mm. The DBD is powered by an AC high voltage in the range of ±10 kV with frequency in a range of 2-7 kHz. It is found that the discharge with KCl liquid electrode yield higher power than that with stainless steel electrode.

  18. Production and conversion of color centers in OH --doped KCl polycrystals colored electrolytically

    NASA Astrophysics Data System (ADS)

    Wang, Fen; Gu, Hongen; Qin, Fang; Liu, Jia; Chen, Weiwei

    2010-02-01

    OH --doped KCl polycrystals are colored electrolytically by using a pointed cathode and a flat anode at various temperatures and voltages. Characteristic O -, OH -, U, U A and Cu + absorption peaks are observed in resolved absorption spectra of uncolored polycrystals. Characteristic V 2, V 3, Cu +, O 2-- Va+, I2-, I 2, H 2O - and F spectral bands are observed at room temperature in Kubelka-Munk functions of colored polycrystals. Current-time curve for electrolytic coloration of an OH --doped KCl polycrystal and its relationship with electrolytic coloration process are given. Production and conversion of color centers are explained.

  19. Enhanced ionic conductivity and optical studies of plasticized (PEO-KCl) solid polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Chapi, Sharanappa; H, Devendrappa

    2015-06-01

    Solid polymer electrolytes (SPEs) based on Polyethylene oxide (PEO) doped with potassium chloride (KCl) were prepared by the solution cast technique. The conductivity increases from 10-10 to 10-6 Scm-1 at 303K with dopant. Optical absorption study shows that the direct & indirect optical band gaps were found decreased from 5.45-4.46eV and 4.96-3.86eV respectively with increasing the KCl. The XRD patterns reveal increasing the amorphous with increasing the dopent. The obtained results suggest that, these polymer systems are suitable candidates for solid state battery, electro chromic devices & optoelectronics display etc.

  20. The reduction of chlorine on carbon in AlCl3-KCl-NaCl melts

    NASA Technical Reports Server (NTRS)

    Holleck, G. L.

    1971-01-01

    Using a rotating vitreous carbon disk electrode, the kinetic parameters for chlorine reduction in an AlCl3-KCl-NaCl (57.5-12.5-30 mol percent) melt were determined. It was found that the reduction of chlorine occurs according to two paths, with the first step probably being rate-determining.

  1. Single PTCDA molecules on planar and stepped KCl and NaCl(100) surfaces

    NASA Astrophysics Data System (ADS)

    Aldahhak, H.; Schmidt, W. G.; Rauls, E.

    2015-11-01

    First principles calculations have been employed to investigate the adsorption of single PTCDA molecules on KCl(100) and NaCl(100) surfaces. The lateral and rotational diffusion barriers as well as the electronic and the geometric aspects of single PTCDA molecules adsorbed on planar terraces as well as at defective steps have been studied in detail.

  2. Freezing, melting, nonwetting, and coexistence in (KCl)32 John P. Rose and FL Stephen Berry

    E-print Network

    Berry, R. Stephen

    Freezing, melting, nonwetting, and coexistence in (KCl)32 John P. Rose and FL Stephen Berry that of homogeneousclusters. The melting and freezing, nonwetting, and the complexity of the potential surfaceof (KC1)33areCl clustersexhibit simpleisomerizationdynamics, large NaCl clusters exhibit freezing/melting behavior sim- ilar

  3. 3-D KINEMATICAL CONSERVATION LAWS (KCL): EQUATIONS OF EVOLUTION OF A SURFACE

    E-print Network

    3-D KINEMATICAL CONSERVATION LAWS (KCL): EQUATIONS OF EVOLUTION OF A SURFACE K. R. ARUN AND P and propagation, we need the governing equations in the form a system of physically realistic conservation laws. In this paper we derive and analyze such conservation laws in a specially defined ray coordinate system

  4. Adsorption of PTCDA on NaCl(100) and KCl(100) H. Aldahhak a

    E-print Network

    Schmidt, Wolf Gero

    molecular self organisation. Potassium chloride (KCl) and sodium chloride (NaCl) are the most simple repre, Universität Paderborn, 33100 Paderborn, Germany a b s t r a c ta r t i c l e i n f o Article history: Received

  5. Quantitative megavoltage radiation therapy dosimetry using the storage phosphor KCl:Eu2+

    PubMed Central

    Han, Zhaohui; Driewer, Joseph P.; Zheng, Yuanshui; Low, Daniel A.; Li, H. Harold

    2009-01-01

    This work, for the first time, reports the use of europium doped potassium chloride (KCl:Eu2+) storage phosphor for quantitative megavoltage radiation therapy dosimetry. In principle, KCl:Eu2+ functions using the same photostimulatated luminescence (PSL) mechanism as commercially available BaFBr0.85I0.15:Eu2+ material that is used for computed radiography (CR) but features a significantly smaller effective atomic number—18 versus 49—making it a potentially useful material for nearly tissue-equivalent radiation dosimetry. Cylindrical KCl:Eu2+ dosimeters, 7 mm in diameter and 1 mm thick, were fabricated in-house. Dosimetric properties, including radiation hardness, response linearity, signal fading, dose rate sensitivity, and energy dependence, were studied with a laboratory optical reader after irradiation by a linear accelerator. The overall experimental uncertainty was estimated to be within ±2.5%. The findings were (1) KCl:Eu2+ showed satisfactory radiation hardness. There was no significant change in the stimulation spectra after irradiation up to 200 Gy when compared to a fresh dosimeter, indicating that this material could be reused at least 100 times if 2 Gy per use was assumed, e.g., for patient-specific IMRT QA. (2) KCl:Eu2+ exhibited supralinear response to dose after irradiation from 0 to 800 cGy. (3) After x ray irradiation, the PSL signal faded with time and eventually reached a fading rate of about 0.1%?h after 12 h. (4) The sensitivity of the dosimeter was independent of the dose rate ranging from 15 to 1000 cGy?min. (5) The sensitivity showed no beam energy dependence for either open x ray or megavoltage electron fields. (6) Over-response to low-energy scattered photons was comparable to radiographic film, e.g., Kodak EDR2 film. By sandwiching dosimeters between low-energy photon filters (0.3 mm thick lead foils) during irradiation, the over-response was reduced. The authors have demonstrated that KCl:Eu2+ dosimeters have many desirable dosimetric characteristics that make the material conducive to radiation therapy dosimetry. In the future, a large-area KCl:Eu2+-based CR plate with a thickness of the order of a few microns, created using modern thin film techniques, could provide a reusable, quantitative, high-resolution two-dimensional dosimeter with minimal energy dependence. PMID:19746808

  6. Critical point and vapor pressure of ionic fluids including NaCl and KCl

    NASA Astrophysics Data System (ADS)

    Pitzer, Kenneth S.

    1984-03-01

    The critical properties and the vapor and liquid densities of NaCl, KCl, and the primite-model ionic fluid are compared on a corresponding-states basis. In preparation for these comparisons the vapor density of NaCl at very high temperature is calculated from the accurate molecular parameters. The very recent treatment of Gillan is adopted for the primitive model. The liquid properties of KCl and NaCl follow corresponding states exactly but there is some discrepancy for the ion pair in the vapor. The differences are greater for the primitive model but again the agreement is quite good for the liquid. Critical properties are reported for all three fluids.

  7. Electrochemical study of uranium cations in LiCl-KCl melt using a rotating disk electrode

    SciTech Connect

    Bae, Sang-Eun; Kim, Dae-Hyun; Kim, Jong-Yoon; Park, Tae-Hong; Cho, Young Hwan; Yeon, Jei-Won; Song, Kyuseok

    2013-07-01

    A rotating disk electrode (RDE) measurement technique was employed to investigate the electrochemical REDOX reactions of actinide (An) and lanthanide (Ln) ions in LiCl-KCl molten salt. By using RDE, it is possible to access more exact values of the diffusion coefficient, Tafel slope, and exchange current density. In this work, we constructed RDE setup and electrodes for RDE measurements in high temperature molten salt and measured the electrochemical parameters of the An and Ln ions. The RDE setup is composed of a Pine model MSRX rotator equipped with a rod type of W electrode. The active electrode area was confined to the planar part of the W rod by making meniscus at the LiCl-KCl melt surface.

  8. The role of valence-band excitation in laser ablation of KCl

    NASA Technical Reports Server (NTRS)

    Haglund, Richard F., Jr.; Tang, Kai; Bunton, Patrick H.; Wang, Ling-Jun

    1991-01-01

    We present recent measurements of excited-atom and ion emission from KCl surfaces illuminated by vacuum-ultraviolet synchrotron radiation (h-nu = 8-28 eV) and ultraviolet laser light (h-nu = 4 eV). At low intensities characteristic of the synchrotron experiments, excited atoms are desorbed by simple valence-band excitation process involving the metallization of the KCl surface. At the higher intensities typical of laser desorption and ablation, we observe a strong decrease in K emission as a function of the number of laser shots, but an essentially constant yield of Cl. K(+) and Cl(-) emission at high intensities show similar behavior. The energetics of these desorption phenomena can be treated in a bond-orbital model which shows that creation of a single valence hole is sufficient to excite an ion to an anti-bonding state.

  9. Preparation and dielectric properties of oxide added NaCl KCl polycrystals

    NASA Astrophysics Data System (ADS)

    Priya, M.; Mahadevan, C. K.

    2008-01-01

    Pure and ZnO and CdO added (separately) polycrystals of NaCl, KCl and (NaCl) 0.5(KCl) 0.5 were prepared by the melt method. Density, atomic absorption spectroscopic and X-ray diffraction measurements indicate that the ZnO and CdO have entered into the lattices of alkali halide crystals. The dielectric measurements indicate that the dielectric parameters increase with the increase in temperature. Also, the dielectric constant and dielectric loss factor values decreased whereas the electrical conductivities increased with the increase in frequency of the AC applied. Significant changes have been observed with the dielectric parameters caused by ZnO and CdO additions. Also, the depth profile study was carried out on CdO added crystals which indicates that the dopant addition creates different layers along the crystal with increase of dopant content from top to bottom.

  10. Current-induced composition gradients in molten LiCl-KCl battery electrolytes

    SciTech Connect

    Braunstein, J.; Cantor, S.; Vallet, C.E.

    1985-01-01

    Current induced composition gradients were demonstrated in molten LiCl-KCl eutectic mixture, the electrolyte of a LiAl/LiCl-KCl/FeS/sub x/ battery. The gradients were produced by electrolysis of the salt between LiAl electrodes at currents of 50-100 mA cm/sup -2/, and quenching. Analysis of composition profiles in quenched samples was by atomic absorption spectroscopy (AA), which gave good precision, and by x-ray fluorescence spectroscopy in a scanning electron microscope (SEM/EDX), which gave good distance resolution. Work is in progress to improve the precision of the SEM/EDX measurements to that demonstrated in model systems. 5 references, 5 figures, 1 table.

  11. Effect of NaCl and KCl doping on the growth of sulphamic acid crystals

    NASA Astrophysics Data System (ADS)

    Thaila, T.; Kumararaman, S.

    2011-11-01

    The nonlinear optical single crystals of doped sulphamic acid (SA) were grown from aqueous solution by doping with NaCl and KCl using slow evaporation method. Powder X-ray diffraction studies confirm that the grown crystals belong to orthorhombic system. The density and melting point measurements of the grown crystals were determined by floatation technique and capillary tube method, respectively. The range of optical transmittance was ascertained by recording the UV-Vis-NIR spectrum. Atomic absorption study reveals the presence of dopants in the doped crystals. The thermal analyses indicated that the doped SA crystals are more stable than pure crystals. The Vicker's microhardness studies revealed that the dopants increased the hardness of the crystals. SHG efficiency studies of the crystals are found to be increased in the presence of NaCl and KCl dopants.

  12. Ab initio investigation of surface phonons on the (001) surface of KCl

    NASA Astrophysics Data System (ADS)

    Tütüncü, H. M.; Srivastava, G. P.

    2015-07-01

    We present an ab initio investigation of localised and resonant phonons on the relaxed KCl(001) surface. Our calculated results are in good accordance with recent high-resolution helium atom scattering measurements. The energy locations and atomic displacement patterns corresponding to a few characteristic surface phonons, such as the Rayleigh, Love, Wallis and Lucas modes, have been identified, and compared and contrasted with their counterparts obtained from a previous shell model calculation.

  13. Temperature dependence of the photostimulated luminescence in KCl:Eu2+

    NASA Astrophysics Data System (ADS)

    Xiao, Zhiyan; Hansel, Rachael; Zhang, Lei; Li, H. Harold

    2014-05-01

    The goal of this work is to understand the physical mechanism behind the signal stabilization process in KCl:Eu2+, a storage phosphor material that has generated renewed interest due to its potential in radiation therapy dosimetry application. The temperature dependency of the photostimulated luminescence (PSL) spectra and intensity vs. time post X-ray irradiation was measured. Commercial BaFBr:Eu2+ materials were included in this study for comparison. Unlike BaFBr:Eu2+, broadening of the F(Cl-) stimulation band and red-shift of the peak were observed for KCl:Eu2+ with increasing temperature. For irradiations at temperatures lower than 200 K, PSL intensity of KCl:Eu2+ showed recuperation behavior in the first 2 h post-irradiation and stayed almost constant with time thereafter. Moreover, spatially-correlated storage centers increased from 24% for irradiation at 50 K to 31% at 195 K and almost 100% at room temperature. The data suggest that certain types of charge storage-centers were mobile and contribute to the fast fading in PSL.

  14. Preparation and properties of KCl-doped Cu2O thin film by electrodeposition

    NASA Astrophysics Data System (ADS)

    Yu, Xiaojiao; Li, Xinming; Zheng, Gang; Wei, Yuchen; Zhang, Ama; Yao, Binghua

    2013-04-01

    With the indium tin oxide-coated glass as working electrode, cuprous oxide thin film is fabricated by means of electrodeposition. The effects of KCl doped and annealing treatment upon Cu2O thin film morphology, surface resistivity, open-circuit voltage, electric conduction types and visible light response are studied. The research results indicate that KCl doped has a great effect upon Cu2O crystal morphology, thus, making Cu2O thin film surface resistivity drop, and the open-circuit voltage increase and that electric conduction types are transformed from p type into n type, and the visible light (400-500 nm) absorption rate is slightly reduced. Annealing treatment can obviously decrease Cu2O thin film surface resistivity and improve its open-circuit voltage. When KCl concentration in electrolytic solution reaches 7 mmol/L, Cu2O thin film morphology can be changed from the dendritic crystal into the cubic crystal and Cu2O thin film surface resistivity decreases from the initial 2.5 × 106 ? cm to 8.5 × 104 ? cm. After annealing treatment at 320 °C for 30 min, the surface resistivity decreases to 8.5 × 102 ? cm, and the open-circuit voltage increases from the initial 3.1 mV to 79.2 mV.

  15. Phase relations in the hydrous CMAS pyrolite in presence of KCl at 2 GPa

    NASA Astrophysics Data System (ADS)

    Safonov, O.

    2012-04-01

    In the upper mantle, chlorides are constituents of concentrated aqueous solutions (brines), as well as chloride-carbonate and carbonatite melts. Mineral assemblages coming from diverse depth levels show that mobile (K, Na)Cl-bearing fluids are able to provoke intensive metasomatism of the peridotitic mantle accompanied by melting. Scarce experimental studies on influence of brines on mineral equilibria in the peridotitic mantle (Stalder et al., 2008; Chu et al., 2011) indicate that influence of chlorides on water activity in a fluid equilibrated with forsterite enstatite at pressures above 2 GPa is very similar to their effect at lower "crustal" pressures (e.g. Aranovich, Newton, 1997): decrease of the H2O activity with an increase of the salt content results in an increase of the melting temperature of silicates. Nevertheless, these experiments were performed in the Al-free systems. Presence of Al would provoke an active interaction of alkali chlorides, namely KCl, with silicates with formation of new K-Al-bearing phases, such as phlogopite (in presence of H2O), which would influence on the melting of complex assemblages. In order to investigate an effect of KCl on phase relations in the Al2O3, CaO, Na2O-rich hydrous peridotite and on stability of garnet, pyroxenes, and amphiboles, in particular, experiments on interaction of the model CMAS pyrolite Fo57En17Prp14Di12 (+0.3 wt. % of Na2O) with the H2O-KCl fluid were performed at 2 GPa in the temperature interval 900-1200. Mixtures of synthetic forsterite, diopside, enstatite and pyrope in the above weight ratio were mixed with 14 wt. % of Mg(OH)2 corresponding to 4.4 wt. % of H2O in the system. 2.4, 3.7, 5 and 10 wt. % of KCl were added to silicate-H2O mixture. Experiments were performed using a piston-cylinder apparatus with ½-inch talc high-pressure cells calibrated via brucite = periclase + H2O and albite = jadeite + quartz equilibria curves. Temperature was controlled with accuracy ?1 with the W95Re5/W80Re20 thermocouple. Spherical and tube Pt capsules with 0.2 mm-thick walls were used in the experiments. Run products were analyzed using CamScan MV2300 (VEGA TS 5130MM) electron microscope equipped with EDS INCA-Energy-250. The subsolidus assemblage of the model pyrolite (< 1025OC) containing 4.4 wt. % of H2O at 2.5 GPa includes forsterite (Fo), low-Al2O3 (below 0.5 wt. %) clinopyroxene (Cpx), orthopyroxene (Opx) with up to 7 wt. % of Al2O3, pargasite-tschermackite amphibole (Amp), pyrope-grossular garnet (Grt), and minute spinel (Spl). It is consistent with the results of experiments with amphibole-bearing lherzolite (e.g. Niida, Green, 1999). Reaction relations 3/2Opx + 1/2Fo + 1/2Amp = Grt + Cpx + 1/2H2O are observed in the run samples. Melting apparently begins in the temperature interval 1025-1050 and results in gradual disappearance of amphibole. In general, similar relations are available in presence of 2.4 wt. % of KCl. However, reaction 6Opx + Fo + Amp + KCl = [Cl-Phl + Phl] + Grt + 2Cpx results in formation of Cl-bearing phlogopite solid solution, Phl (up to 1 wt. % of Cl). It seems to be stable at higher temperatures (apparently, above 1200) with respect to amphibole, consistently with the experimental data on melting of phlogopite and amphibole-bearing peridotites at pressures >1.5 GPa (Modreski, Boettcher, 1973; Mysen, Boettcher, 1975; Mengel, Green, 1989). Garnet, orthopyroxene, and amphibole, i.e. all alumina-rich phases of the "starting" KCl-free peridotite, are totally disappear with addition of 3.7 wt. % and more of KCl, while the assemblage of Cl-bearing phlogopite with Al-poor clinopyroxene and olivine is stable. The solidus temperature of the H2O-bearing pyrolite with addition of KCl is about 900 at 2.4 wt.% of KCl and seems to be much lower at 10 wt. % of KCl. Anyway, these temperatures are more than by 100 lower of the melting temperature of the H2O-bearing pyrolite without KCl, as well as Cl-free Di+Phl assemblage (Modreski, Boettcher, 1973). Apparently, decrease of the temperature is related to solubility of Cl in

  16. Ionic conductivity studies in crystalline PVA/NaAlg polymer blend electrolyte doped with alkali salt KCl

    NASA Astrophysics Data System (ADS)

    Sheela, T.; Bhajantri, R. F.; Ravindrachary, V.; Pujari, P. K.; Rathod, Sunil G.; Naik, Jagadish

    2014-04-01

    Potassium Chloride (KCl) doped poly(vinyl alcohol) (PVA)/sodium alginate (NaAlg) in 60:40 wt% polymer blend electrolytes were prepared by solution casting method. The complexation of KCl with host PVA/NaAlg blend is confirmed by FTIR and UV-Vis spectra. The XRD studies show that the crystallinity of the prepared blends increases with increase in doping. The dc conductivity increases with increase in dopant concentration. Temperature dependent dc conductivity shows an Arrhenius behavior. The dielectric properties show that both the dielectric constant and dielectric loss increases with increase in KCl doping concentration and decreases with frequency. The cole-cole plots show a decrease in bulk resistance, indicates the increase in ac conductivity, due to increase in charge carrier mobility. The doping of KCl enhances the mechanical properties of PVA/NaAlg, such as Young's modulus, tensile strength, stiffness.

  17. Salt-Zeolite Ion Exchange Equilibrium Studies for Complete Set of Fission Products in Molten LiCl-KCl

    SciTech Connect

    Tae-Sic Yoo; Steven M. Frank; Michael F. Simpson; Paula A. Hahn; Terry J. Battisti; Supathorn Phongikaroon

    2010-09-01

    This paper presents results on LiCl-KCl based molten salts/zeolite-A contact experiments and the associated equilibrium ion exchange model. Experiments examine the contact behaviors of various ternary salts (LiCl-KCl-YCl3, LiCl-KCl-LaCl3, and LiCl-KCl-PrCl3) and quaternary salts (LiCl-KCl-CsCl-NdCl3 and LiCl-KCl-CsCl-SrCl2) with the zeolite-A. The developed equilibrium model assumes that there are ion exchange and occlusion sites, both of which are in equilibrium with the molten salt phase. A systematic approach in estimating total occlusion capacity of the zeolite-A is developed. The parameters of the model, including the total occlusion capacity of the zeolite-A, were determined from fitting experimental data collected via multiple independent studies including the ones reported in this paper. Experiments involving ternary salts were used for estimating the parameters of the model, while those involving quaternary salts were used to validate the model.

  18. Thermogenic activity of the Ca2+-ATPase from blue marlin heater organ: regulation by KCl and temperature.

    PubMed

    da Costa, Danielly Cristiny Ferraz; Landeira-Fernandez, Ana Maria

    2009-11-01

    This work shows that vesicles derived from the blue marlin heater organ retain a sarcoplasmic reticulum (SR) Ca(2+)-ATPase that can interconvert different forms of energy. During the hydrolysis of ATP part of the energy is always converted into heat, and the other part can be converted into work (Ca(2+) transport) or heat, depending on the temperature and the presence of KCl in the reaction medium. At 15 degrees C, where KCl stimulates the activity approximately threefold, measurements of the amount of heat released per mole of ATP hydrolyzed (DeltaH(cal)) show similar values (approximately -11 kcal/mol) in the presence or absence of a Ca(2+) gradient. At 25 degrees C, KCl activates the enzyme to the same extent as at 15 degrees C, but inhibits the production of extra heat by SR Ca(2+)-ATPase when a Ca(2+) gradient is built up across the membrane. The DeltaH(cal) values found in the presence of a Ca(2+)-gradient were -26.2 +/- 2.9 kcal/mol (n = 7) in control experiments and -16.1 +/- 1.5 (n = 14) in the presence of 100 mM KCl. At 35 degrees C, KCl has a smaller effect ( approximately 1.5-fold) on activating the enzyme. Similar to SR Ca(2+)-ATPase from mammals, at this temperature the enzyme produces almost twice the amount of heat per mole of ATP hydrolyzed in the presence of a Ca(2+) gradient and KCl has no effect at all on this increment. These data suggest that the marlin SR Ca(2+)-ATPase may play an important role in heater organ thermogenesis and that KCl has the potential for regulating the heat production catalyzed by the enzyme. PMID:19710387

  19. Temporal signal stability of KCl:Eu{sup 2+} storage phosphor dosimeters

    SciTech Connect

    Xiao Zhiyan; Hansel, Rachael; Chen Haijian; Du Dongsu; Yang Deshan; Li, H. Harold

    2013-02-15

    Purpose: Current KCl:Eu{sup 2+} prototype dosimeters require a wait time of 12 h between irradiation and dosimetric readout. Although irradiating the dosimeters in the evening and reading on the following day works well in the clinical schedule, reducing the wait time to few hours is desirable. The purposes of this work are to determine the origin of the unstable charge-storage centers and to determine if these centers respond to optical or thermal excitation prior to dosimetric readout. Methods: Pellet-style KCl:Eu{sup 2+} dosimeters were fabricated in-house for this study. A 6 MV photon beam was used to irradiate the dosimeters. After x ray irradiation, dosimeters were subjected to external excitation with near-infrared (NIR) light, ultraviolet (UV) light, or thermal treatment. Photostimulated luminescence (PSL) signal's temporal stability was subsequently measured at room temperature over a few hours using a laboratory PSL readout system. The dosimeters were also placed in a cryostat to measure the temperature dependence of the temporal stability down to 10 K. Results: Strong F-band was present in the PSL stimulation spectrum, indicating that F-centers were the electron-storage centers in KCl:Eu{sup 2+} where an electron was stored at a chlorine anion vacancy. Due to deep energy-depth (2.2 eV), F-centers were probably not responsible for the fast fading in the first a few hours post x ray irradiation. In addition, weak NIR bands were present. However, there was no change in PSL stabilization rate with intense NIR excitation, suggesting that the NIR bands played no role in the PSL fading. At temperatures lower than 77 K there was almost no signal fading with time. Noticeable PSL was observed for undoped KCl samples at room temperature, suggesting that Cl{sub 2}{sup -} V{sub k} centers served as hole-storage centers for both undoped and doped KCl where a hole was trapped by a chlorine molecular ion. V{sub k} centers were stable at low temperature and became mobile at room temperature, probably causing the observed PSL fading with time. On the other hand, V{sub k} center could be stabilized by Eu{sup 2+} activator or oxygen in the lattice, leading to the stable component in the PSL. A thermal process at elevated temperatures (60 Degree-Sign C or higher) was able to significantly accelerate the migration process resulting in a fast stabilization of PSL. However, this could not be accomplished using intense UV excitation. Conclusions: Thermal treatment enables KCl:Eu{sup 2+} prototypes to be ready for readout in 1 h without the need of applying a large time-dependent correction factor. However, this cannot be achieved using optical preexcitation.

  20. Thermal Properties of LiCl-KCl Molten Salt for Nuclear Waste Separation

    SciTech Connect

    Sridharan, Kumar; Allen, Todd; Anderson, Mark; Simpson, Mike

    2012-11-30

    This project addresses both practical and fundamental scientific issues of direct relevance to operational challenges of the molten LiCl-KCl salt pyrochemical process, while providing avenues for improvements in the process. In order to understand the effects of the continually changing composition of the molten salt bath during the process, the project team will systematically vary the concentrations of rare earth surrogate elements, lanthanum, cerium, praseodymium, and neodymium, which will be added to the molten LiCl-KCl salt. They will also perform a limited number of focused experiments by the dissolution of depleted uranium. All experiments will be performed at 500 deg C. The project consists of the following tasks. Researchers will measure density of the molten salts using an instrument specifically designed for this purpose, and will determine the melting points with a differential scanning calorimeter. Knowledge of these properties is essential for salt mass accounting and taking the necessary steps to prevent melt freezing. The team will use cyclic voltammetry studies to determine redox potentials of the rare earth cations, as well as their diffusion coefficients and activities in the molten LiCl-KCl salt. In addition, the team will perform anodic stripping voltammetry to determine the concentration of the rare earth elements and their solubilities, and to develop the scientific basis for an on-line diagnostic system for in situ monitoring of the cation species concentration (rare earths in this case). Solubility and activity of the cation species are critically important for the prediction of the salt's useful lifetime and disposal.

  1. Equilibria in the ternary system SrCl2-KCl-H2O and the quaternary system SrCl2-KCl-NaCl-H2O at 323 K

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao; Sang, Shi-Hua; Zhong, Si-Yao; Huang, Wang-Yin

    2015-12-01

    The experimental studies on phase equilibria in the ternary system SrCl2-NaCl-H2O and the quaternary system SrCl2-KCl-NaCl-H2O at 323 K were done by the method of isothermal solution saturation. Solubilities and densities of the solution were determined experimentally. The phase diagrams and density-composition diagrams were plotted based on the experimental data. The phase diagram of the ternary system SrCl2-KCl-H2O at 323 K consists of one invariant point, two univariant curves, and two crystallization regions (SrCl2 · 6H2O and KCl). The phase diagrams of the quaternary system SrCl2-KCl-NaCl-H2O at 323 K consist of one invariant point, three univariant curves, and three crystallization regions (SrCl2 · 6H2O, NaCl, and KCl). A brief discussion of the experimental results is described.

  2. The electrochemical properties of LiCl-KCl melt held in contact with samarium

    NASA Astrophysics Data System (ADS)

    Kovalevskii, A. V.; El'Kin, O. V.

    2011-03-01

    The dependence of the reaction capacity ( R) of a LiCl (60 mol %)-KCl melt held in contact with samarium at 873 and 973 K on the concentration of the corroding metal in the melt was obtained. The R value was used to estimate the content of Sm2+ ions in the lowest oxidation state, their fraction, and the conventional equilibrium constant of the 2Sm3+ + Sm ? 3Sm2+ reaction. The results were used to determine the particular mechanism of currentless transfer of samarium in the chloride melt onto a substrate of a more electropositive metal (in particular, onto nickel).

  3. Deep Subthreshold ?- Production in Ar+KCl Reactions at 1.76AGeV

    NASA Astrophysics Data System (ADS)

    Agakishiev, G.; Balanda, A.; Bassini, R.; Belver, D.; Belyaev, A. V.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Braun-Munzinger, P.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; Díaz, J.; Dohrmann, F.; Dybczak, A.; Eberl, T.; Fabbietti, L.; Fateev, O. V.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gil, A.; Gilardi, C.; Golubeva, M.; González-Díaz, D.; Guber, F.; Hennino, T.; Holzmann, R.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Krizek, F.; Krücken, R.; Kühn, W.; Kugler, A.; Kurepin, A.; Lang, S.; Lange, J. S.; Lapidus, K.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Morinière, E.; Mousa, J.; Müntz, C.; Naumann, L.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy-Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Sudol, M.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y. V.; Zhou, P.; Zumbruch, P.

    2009-09-01

    We report first results on a deep subthreshold production of the doubly strange hyperon ?- in a heavy-ion reaction. At a beam energy of 1.76AGeV the reaction Ar+KCl was studied with the High Acceptance Di-Electron Spectrometer at SIS18/GSI. A high-statistics and high-purity ? sample was collected, allowing for the investigation of the decay channel ?-???-. The deduced ?-/(?+?0) production ratio of (5.6±1.2-1.7+1.8)×10-3 is significantly larger than available model predictions.

  4. Deep subthreshold Xi;{-} production in Ar + KCl reactions at 1.76A GeV.

    PubMed

    Agakishiev, G; Balanda, A; Bassini, R; Belver, D; Belyaev, A V; Blanco, A; Böhmer, M; Boyard, J L; Braun-Munzinger, P; Cabanelas, P; Castro, E; Chernenko, S; Christ, T; Destefanis, M; Díaz, J; Dohrmann, F; Dybczak, A; Eberl, T; Fabbietti, L; Fateev, O V; Finocchiaro, P; Fonte, P; Friese, J; Fröhlich, I; Galatyuk, T; Garzón, J A; Gernhäuser, R; Gil, A; Gilardi, C; Golubeva, M; González-Díaz, D; Guber, F; Hennino, T; Holzmann, R; Iori, I; Ivashkin, A; Jurkovic, M; Kämpfer, B; Kanaki, K; Karavicheva, T; Kirschner, D; Koenig, I; Koenig, W; Kolb, B W; Kotte, R; Krizek, F; Krücken, R; Kühn, W; Kugler, A; Kurepin, A; Lang, S; Lange, J S; Lapidus, K; Liu, T; Lopes, L; Lorenz, M; Maier, L; Mangiarotti, A; Markert, J; Metag, V; Michalska, B; Michel, J; Mishra, D; Morinière, E; Mousa, J; Müntz, C; Naumann, L; Otwinowski, J; Pachmayer, Y C; Palka, M; Parpottas, Y; Pechenov, V; Pechenova, O; Pietraszko, J; Przygoda, W; Ramstein, B; Reshetin, A; Roy-Stephan, M; Rustamov, A; Sadovsky, A; Sailer, B; Salabura, P; Schmah, A; Sobolev, Yu G; Spataro, S; Spruck, B; Ströbele, H; Stroth, J; Sturm, C; Sudol, M; Tarantola, A; Teilab, K; Tlusty, P; Traxler, M; Trebacz, R; Tsertos, H; Wagner, V; Weber, M; Wisniowski, M; Wojcik, T; Wüstenfeld, J; Yurevich, S; Zanevsky, Y V; Zhou, P; Zumbruch, P

    2009-09-25

    We report first results on a deep subthreshold production of the doubly strange hyperon Xi;{-} in a heavy-ion reaction. At a beam energy of 1.76A GeV the reaction Ar + KCl was studied with the High Acceptance Di-Electron Spectrometer at SIS18/GSI. A high-statistics and high-purity Lambda sample was collected, allowing for the investigation of the decay channel Xi;{-} --> Lambdapi;{-}. The deduced Xi;{-}/(Lambda + Sigma;{0}) production ratio of (5.6 +/- 1.2_{-1.7};{+1.8}) x 10;{-3} is significantly larger than available model predictions. PMID:19905504

  5. Hyperon production in Ar + KCl collisions at 1.76A GeV

    NASA Astrophysics Data System (ADS)

    Agakishiev, G.; Balanda, A.; Bannier, B.; Bassini, R.; Belver, D.; Belyaev, A.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; D?az, J.; Dohrmann, F.; Dybczak, A.; Eberl, T.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gil, A.; Gilardi, C.; Golubeva, M.; González-D?az, D.; Guber, F.; Gumberidze, M.; Heilmann, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Huck, P.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Krizek, F.; Krücken, R.; Kühn, W.; Kugler, A.; Kurepin, A.; Lang, S.; Lange, J. S.; Lapidus, K.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Morinière, E.; Mousa, J.; Müntz, C.; Naumann, L.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pérez Cavalcanti, T.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy-Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wendisch, C.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.; Zhou, P.; Zumbruch, P.

    2011-02-01

    We present transverse momentum spectra, rapidity distribution and multiplicity of ? -hyperons measured with the HADES spectrometer in the reaction Ar(1.76AGeV) + KCl . The yield of ?^{{-}}_{} is calculated from our previously reported ?^{{-}}_{}/( ? + ?^{{0}}_{}) ratio and compared to other strange particle multiplicities. Employing a strangeness balance equation the multiplicities of the yet unmeasured ?^{{±}}_{} -hyperons can be estimated. Finally a statistical hadronization model is used to fit the yields of ?-_{} , K+, K 0 s , K-, ? , ? and ?-_{} . The resulting chemical freeze-out temperature of T = (76±2) MeV is compared to the measured slope parameters obtained from fits to the transverse mass distributions of the different particles.

  6. An investigation of the critical liquid-vapor properties of dilute KCl solutions

    USGS Publications Warehouse

    Potter, R.W., II; Babcock, R.S.; Czamanske, G.K.

    1976-01-01

    The three parameters that define the critical point, temperature, pressure, and volume have been experimentally determined by means of filling studies in a platinum-lined system for five KCl solutions ranging from 0.006 to 0.568 m. The platinum-lined vessels were used to overcome the problems with corrosion experienced by earlier workers. The critical temperature (tc), pressure (Pc), and volume (Vc) were found to fit the equations {Mathematical expression} from infinite dilution to 1.0 m. ?? 1976 Plenum Publishing Corporation.

  7. Actinides recovery from irradiated metallic fuel in LiCl-KCl melts

    NASA Astrophysics Data System (ADS)

    Murakami, T.; Rodrigues, A.; Ougier, M.; Iizuka, M.; Tsukada, T.; Glatz, J.-P.

    2015-11-01

    Electrorefining of irradiated metallic fuels was successfully demonstrated: Actinides (U, Pu, Np, Am and Cm) in the fuels were dissolved in LiCl-KCl melts with high dissolution ratios, while U was selectively deposited on a solid cathode and the simultaneous recovery of actinides in a liquid Cd cathode was confirmed. The behavior of actinides, the fuel matrix stabilizer Zr and fission products such as lanthanide, alkaline, alkaline earth and noble metal, at the electrorefining is discussed based on the ICP-MS analysis of the samples taken from molten salt electrolyte, anode fuel residues and cathode deposits.

  8. Phase relations in the system NaCl-KCl-H2O: IV. Differential thermal analysis of the sylvite liquidus in the KCl-H2O binary, the liquidus in the NaCl-KCl-H2O ternary, and the solidus in the NaCl-KCl binary to 2 kb pressure, and a summary of experimental data for thermodynamic-PTX analysis of solid-liquid equilibria at elevated P-T conditions

    USGS Publications Warehouse

    Chou, I.-Ming; Sterner, S.M.; Pitzer, Kenneth S.

    1992-01-01

    The sylvite liquidus in the binary system KCl-H2O and the liquidus in the ternary system NaCl-KCl-H2O were determined by using isobaric differential thermal analysis (DTA) cooling scans at pressures up to 2 kbars. Sylvite solubilities along the three-phase curve in the binary system KCl-H2O were obtained by the intersection of sylvite-liquidus isopleths with the three-phase curve in a P-T plot. These solubility data can be represented by the equation Wt.% KCl (??0.2) = 12.19 + 0.1557T - 5.4071 ?? 10-5 T2, where 400 ??? T ??? 770??C. These data are consistent with previous experimental observations. The solidus in the binary system NaCl-KCl was determined by using isobaric DTA heating scans at pressures up to 2 kbars. Using these liquidus and solidus data and other published information, a thermodynamic-PTX analysis of solid-liquid equilibria at high pressures and temperatures for the ternary system has been performed and is presented in an accompanying paper (Part V of this series). However, all experimental liquidus, solidus, and solvus data used in this analysis are summarized in this report (Part IV) and they are compared with the calculated values based on the analysis. ?? 1992.

  9. Growth of NaCl on thin epitaxial KCl films on Ag(100) studied by SPA-LEED

    NASA Astrophysics Data System (ADS)

    Marquardt, Christian; Paulheim, Alexander; Sokolowski, Moritz

    2015-11-01

    We investigated the growth of NaCl on thin (100)-oriented films of KCl by spot profile analysis of low energy electron diffraction (SPA-LEED). The underlying question of this investigation was how the system accommodates to the misfit of - 10% between the NaCl and KCl lattices. The KCl films (3 atomic layers thick) were epitaxially grown on a Ag(100) single crystal. We studied the heteroepitaxial growth of NaCl on KCl at 300 K and at 500 K, respectively. At 300 K, the first NaCl monolayer (ML) grows pseudomorphically on the KCl film. From the second layer onward, the NaCl lattice relaxes. The NaCl multilayers roughen, and a small rotational disorder (± 4°) of the NaCl domains is observed. The roughening results from the formation of multilayer islands of limited lateral size due to the misfit to the pseudomorphic first NaCl layer. At a growth temperature of 500 K, no pseudomorphic NaCl layer forms, instead relaxed multilayer island growth of NaCl is observed from the first layer onward. Similarly to the growth at 300 K, we find NaCl multilayer islands of limited lateral size. For both temperatures, we explain this growth behavior by the misfit that makes the adsorption sites at the island edges of the first relaxed NaCl layer less favorable for larger islands, promoting nucleation of multilayer islands.

  10. Surface Morphology and Microstructural Characterization of KCl Crystals Grown in Halite-Sylvite Brine Solutions by Electron Backscattered Diffraction Techniques

    NASA Astrophysics Data System (ADS)

    Podder, Jiban; Basu, Ritwik; Evitts, Richard William; Besant, Robert William

    2015-11-01

    In this paper, a study on the ternary NaCl-KCl-H2O system was carried out by an extractive metallurgy technique from mixed brine solutions of different compositions at room temperature (23°C). The surface morphology and microstructure were examined using a scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and an energy dispersive X-ray (EDX) spectroscopy. The presence of Na{ }+ was found to reduce the stability of the solutions and increase the crystallization induction period, interfacial energy, energy of formation of the nucleus and greatly reduce the nucleation rate of KCl crystal. The surface morphology of KCl crystals is significantly changed due to presence of 5 to 10% (w/w) of NaCl as impurities in the binary solutions and shows the formation of co-crystals of different crystallographic orientation of NaCl on the KCl surface. In addition X-ray diffraction studies performed on KCl crystals grown in halite-sylvite binary solutions reveals that these crystals are cubic in nature and its lattice constant is 6.2952 Å when the NaCl concentration is small.

  11. Degeneracy of the limited series of solid solutions in the NaCl-KCl-NH4Cl-H2O system at 50°C

    NASA Astrophysics Data System (ADS)

    Elsukov, A. V.; Mazunin, S. A.

    2015-06-01

    The phase equilibria in the NaCl-KCl-NH4Cl-H2O system at 50°C were studied. Sodium chloride was shown to destroy the limited compositions of (K,NH4)Cl and (NH4,K)Cl solid solutions. As the NaCl content increased, the solid solutions of the limited series on the line of monovariant equilibria of (K,NH4)Cl and (NH4,K)Cl with saturated solutions degenerated and the triply saturated solution with the individual salt components NaCl, KCl, and NH4Cl was in nonvariant equilibrium.

  12. 4. pi. physics. [/sup 40/Ar + KCl, 0. 4 to 1. 8 GeV/A

    SciTech Connect

    Sandoval, A.

    1980-03-01

    Exclusive ..pi../sup -/ and charged-particle production in collisions of /sup 40/Ar on KCl are studied at incident energies from 0.4 to 1.8 GeV/A. The correlation between the ..pi../sup -/ and the total charged particle multiplicity confines the reaction along a narrow ridge with no exotic islands of pion production. For high multiplicities the system reaches the total disintegration of target and projectile into singly charged fragments and pions. Every 200 MeV/A datum was taken with a central and inelastic trigger. For central collisions the mean ..pi../sup -/ multiplicity increases linearly with the bombarding energy with no marked discontinuities due to the ..delta..(3,3) resonance. At 1.8 GeV/A evidence for nonthermal ..pi../sup -/ production in central collisions is found. The total c.m. energy in ..pi../sup -/ shows linear dependence on the ..pi../sup -/ multiplicity with a slope of epsilon = 300 MeV/..pi../sup -/. Strange particle production in the central collision of 1.8 GeV/A Ar on KCl is seen. 8 figures.

  13. Experimental observations on electrorefining spent nuclear fuel in molten LiCl-KCl/liquid cadmium system.

    SciTech Connect

    Johnson, T. A.; Laug, D. V.; Li, S. X.; Sofu, T.

    1999-07-14

    Argonne National Laboratory (ANL) is currently performing a demonstration program for the Department of Energy (DOE) which processes spent nuclear fuel from the Experimental Breeder Reactor (EBR-II). One of the key steps in this demonstration program is electrorefining of the spent fuel in a molten LiCl-KCl/liquid cadmium system using a pilot scale electrorefiner (Mk-IV ER). This article summarizes experimental observations and engineering aspects for electrorefining spent fuel in the molten LiCl-KCl/liquid cadmium system. It was found that the liquid cadmium pool acted as an intermediate electrode during the electrorefining process in the ER. The cadmium level was gradually decreased due to its high vapor pressure and vaporization rate at the ER operational temperature. The low cadmium level caused the anode assembly momentarily to touch the ER vessel hardware, which generated a periodic current change at the salt/cathode interface and improved uranium recovery efficiency for the process. The primary current distributions calculated by numerical simulations were used in interpreting the experimental results.

  14. A simplified model of TiH1.65/KClO4 pyrotechnic ignition.

    SciTech Connect

    Chen, Ken Shuang

    2009-04-01

    A simplified model was developed and is presented in this report for simulating thermal transport coupled with chemical reactions that lead to the pyrotechnic ignition of TiH1.65/KClO4 powder. The model takes into account Joule heating via a bridgewire, thermal contact resistance at the wire/powder interface, convective heat loss to the surroundings, and heat released from the TiH1.65- and KClO4-decomposition and TiO2-oxidation reactions. Chemical kinetic sub-models were put forth to describe the chemical reaction rate(s) and quantify the resultant heat release. The simplified model predicts pyrotechnic ignition when heat from the pyrotechnic reactions is accounted for. Effects of six key parameters on ignition were examined. It was found that the two reaction-rate parameters and the thermal contact resistance significantly affect the dynamic ignition process whereas the convective heat transfer coefficient essentially has no effect on the ignition time. Effects of the initial/ambient temperature and electrical current load through the wire are as expected. Ignition time increases as the initial/ambient temperature is lowered or the wire current load is reduced. Lastly, critical needs such as experiments to determine reaction-rate and other model-input parameters and to measure temperature profiles, time to ignition and burn-rate data for model validation as well as efforts in incorporating reaction-rate dependency on pressure are pointed out.

  15. Redox electrochemistry of europium fluoride complexes in an equimolar NaCl-KCl melt

    NASA Astrophysics Data System (ADS)

    Kuznetsov, S. A.; Gaune-Escard, M.

    2011-07-01

    The electrochemical behavior of europium fluoride complexes was studied by different electrochemical methods at a glassy carbon electrode in the temperature range 973-1100 K in the NaCl-KCl melt. The diffusion coefficients of Eu(III) and Eu(II) were determined by linear sweep voltammetry. The standard rate constants of charge transfer for the Eu(III)/Eu(II) redox couple were found on the base cyclic voltammetry, impedance spectroscopy and chronoamperometry data. The formal standard redox potentials EEu(III/Eu(II)? were obtained by linear sweep and cyclic voltammetry. The electrochemical behavior of europium fluoride and europium chloride complexes in NaCl-KCl melt was compared and discussed in connection with the strength and stability of these complexes. It was shown that the formation of stronger fluoride complexes reduced values of diffusion coefficients, standard rate constants for charge transfer of the Eu(III)/Eu(II) redox couple and shifted the formal standard redox potentials to the more electronegative values.

  16. Phase equilibria and volumetric properties of the systems KCl-H 2O and NaCl-KCl-H 2O above 573 K: Equation of state representation

    NASA Astrophysics Data System (ADS)

    Anderko, Andrzej; Pitzer, Kenneth S.

    1993-10-01

    A comprehensive equation of state has been developed for the system KC1-H 2O at high temperatures and pressures. The equation is based on a theoretical model developed earlier for the system NaCl-H 2O. Experimental vapor-liquid equilibrium, solid-liquid equilibrium, and density data have been critically evaluated and used to fit the adjustable parameters of the model. The equation of state reproduces these properties within experimental uncertainty. It is valid for temperatures between 573 K and 973 K and pressures up to 5 kbar. Graphs are presented to provide recommended values of phase compositions and volumetric properties. Furthermore, the equations for NaCl-H 2O and KC1-H 2O have been combined to yield an equation for the ternary system NaCl-KCl-H 2O. The equation reproduces solid-liquid equilibrium data for the ternary system and agrees with the available semiquantitative information about the relative concentration of Na and K in the vapor phase.

  17. Vacuum evaporation of KCl-NaCl salts. Part 1: Thermodynamic modeling of vapor pressures of solid and liquid solutions

    SciTech Connect

    Wang, L.L.; Wallace, T.C.

    1996-02-01

    In electrorefining to purify plutonium scraps and alloys, typically an equal molar KCl-NaCl mixture is used as the molten electrolyte through which the oxidized Pu ions are transported to the cathode where the pure plutonium is produced and settles by gravity to the bottom of the molten salt. In molten salt extraction, molten KCl-NaCl salt or KCl-NaCl salt containing MgCl{sub 2} is used to extract Am from molten Pu. Over the years the spent salts from these processes have accumulated in substantial quantities throughout various Pu processing sites. A promising way to reduce storage space and disposal cost is by first converting the actinide species in the waste salts to oxides through oxygen sparging and then separating the salts from the actinides via a vacuum evaporation process. The separation is possible because of the large difference in the vapor pressure between the chloride salts and the actinide oxides. To aid the optimization of this evaporation separation process and process equipment design, an effort to model the evaporation-condensation process of molten KCl-NaCl solutions was initiated. This article presents the first part of the modeling work in developing vapor pressure relations of the KCl-NaCl system. The methodology of using fundamental thermodynamic relations and data to model the vapor pressure equations for the solid and liquid solutions of the KCl-NaCl system will be presented, and the vapor pressures calculated from the model equation will be compared with the available experimental data. How the model equations are useful in predicting condensate compositions will also be discussed.

  18. XAFS Study on Chlorination of Y2O3 in LiCl-KCl-ZrCl4 Melt

    NASA Astrophysics Data System (ADS)

    Okamoto, Yoshihiro; Yaita, Tsuyoshi; Shiwaku, Hideaki; Suzuki, Shinichi

    2008-11-01

    The chlorination reaction of Y2O3 with ZrCl4 in LiCl-KCl eutectic melt was investigated by X-ray absorption fine structure (XAFS) technique. The chlorination reaction was observed between 773 K and 823 K as the 1st peak shift of the Fourier transform magnitude function |FT(k3?(k))|. The peak corresponding to the nearest Y3+-Cl- correlation was observed in the XAFS analysis at 823 K as the result of the chlorination. It was confirmed that the mixture melts after the reaction is almost equivalent to a molten 5% YCl3-(LiCl-KCl eutectic) mixture.

  19. Solution-crystal-solution oscillatory phase transitions in the KCl-NaCl-H2O system

    NASA Astrophysics Data System (ADS)

    Fedoseev, V. B.; Maksimov, M. V.

    2015-03-01

    Long-term oscillations of a solution-crystal phase transition in the disperse KCl-NaCl-H2O system have been detected. Under steady-state conditions, multiple evaporation of droplets has been observed before the formation of a crystal with subsequent condensation, which completely recovers the dimension of a droplet. An interpretation of the observed phenomenon has been proposed on the basis of the Kelvin and Ostwald-Freundlich size effects, Raoult's law, and features of the phase diagram of the KCl-NaCl system.

  20. (C6H14N2)2[VO(HPO4)5B2O] x H2O x -H3PO4, a novel borophosphate cluster containing a single vanadium centre and linked by hydrogen bonds into a three-dimensional framework.

    PubMed

    Wikstad, Emma; Kritikos, Mikael

    2003-03-01

    The title novel vanadium borophosphate compound, bis(1,4-diazonia[2.2.2]octane) mu(3)-oxo-oxopenta-mu-phosphato-diboronvanadium monohydrate phosphoric acid solvate, containing the cluster anion [VO(PO(3)OH)(5)B(2)O](4-), has been synthesized under mild hydrothermal conditions. Extensive O-H...O and N-H...O hydrogen bonding is observed between the molecular units. PMID:12711766

  1. Phase relations in the system NaCl-KCl-H2O. Part I: Differential thermal analysis of the NaCl-KCl liquidas at 1 atmosphere and 500, 1000, 1500, and 2000 bars

    USGS Publications Warehouse

    Chou, I.-Ming

    1982-01-01

    A simple differential thermal analysis (DTA) technique has been developed to study phase relations of various chemical systems at elevated pressures and temperatures. The DTA system has been calibrated against known melting temperatures in the system NaCl-KCl. Isobaric sections of the liquidus in the system NaCl-KCl have been determined at pressures of 1 atmosphere and 500, 1000, 1500, and 2000 bars. Using the least-squares method, the following equation was used to fit the experimental data: T(??C)= ??? i=0 6aiXiKCl where T is the liquidus temperature, XKCl is mole fraction of KCl, and ai (listed below) are the derived empirical constants. {A table is presented}. The liquidus temperatures estimated from these equations are within ??3??C of experimental values. The measured liquidus temperatures at 1 atmosphere agree with the best available data to within 5??C. The melting temperatures for pure end members at higher pressures agree with the values calculated from the Simon equation (Clark, 1959) to within 3??C. No previous melting data are available for the intermediate compositions at elevated pressures. Using the data in both heating and cooling scans, the minimum melting temperature at 1 atmosphere in the system was located at 658?? ?? 3??C where the sample has an equimolar composition. ?? 1982.

  2. Development of high temperature transport technology for LiCl-KCl eutectic salt in pyroprocessing

    SciTech Connect

    Lee, Sung Ho; Lee, Hansoo; Kim, In Tae; Kim, Jeong-Guk

    2013-07-01

    The development of high-temperature transport technologies for molten salt is a prerequisite and a key issue in the industrialization of pyro-reprocessing for advanced fuel cycle scenarios. The solution of a molten salt centrifugal pump was discarded because of the high corrosion power of a high temperature molten salt, so the suction pump solution was selected. An apparatus for salt transport experiments by suction was designed and tested using LiC-KCl eutectic salt. The experimental results of lab-scale molten salt transport by suction showed a 99.5% transport rate (ratio of transported salt to total salt) under a vacuum range of 100 mtorr - 10 torr at 500 Celsius degrees. The suction system has been integrated to the PRIDE (pyroprocessing integrated inactive demonstration) facility that is a demonstrator using non-irradiated materials (natural uranium and surrogate materials). The performance of the suction pump for the transport of molten salts has been confirmed.

  3. Investigation of p-quaterphenyl layers vapor deposited on KCl (001) by Atomic Force Microscopy (AFM)

    NASA Astrophysics Data System (ADS)

    Kintzel, , Jr.; van Winkle, D. H.; Skofronick, J. G.; Safron, S. A.; Flaherty, F.; Smilgies, D.-M.

    2000-03-01

    We have investigated the structural properties of the aromatic molecule p-quaterphenyl (p-4P) vapor deposited onto a KCl (001) surface at a pressure of 10-6 mbars. In a series of AFM studies, thicknesses of p-quaterphenyl varying from 1 to 20 monolayers exhibited unusual features not previously imaged. Included in our observations are: i) needle-like accumulations of the p-quaterphenyl around surface defects, ii) a striped-phase region with a lateral spacing of approximately 25 nm for a nominal monolayer of p-4P, and iii) a thickness range where we found indications for a transition from lying to standing orientation of the molecules.

  4. Spectroscopy study of CO adsorption on F and V centres at the surface of KCl

    NASA Astrophysics Data System (ADS)

    Zecchina, A.; Scarano, D.

    1986-02-01

    Fast deposition of KCl vapours on a NaCl window maintained at 77 K gives highly defective films of deep violet colour. UV-visible and ESR spectra show that the colour centres are mainly represented by F and V centres formed by interaction of Schottky defects created in abnormal quantity during the deposition process at low T. The defects emerging on the surface show reactivity versus CO. In fact unusual positively and negatively charged species are formed at 77 K by CO interaction. Monomeric ( m = 1) and dimeric ( m = 2) negative species (which represent some of the initial products of the CO interaction) are readily transformed into more complex species when the CO pressure is increased.

  5. The formation of tin oxides in thin-film Sn/C/KCl(100) structures

    SciTech Connect

    Yurakov, Yu. A. Ryabtsev, S. V.; Chuvenkova, O. A.; Domashevskaya, E. P.; Nikitenko, A. S.; Kannykin, S. V.; Kushchev, S. B.

    2009-01-15

    The formation of oxides upon the thermal annealing (both in air and vacuum) of island tin films grown on a KCl(100) substrate, which was coated by a thin layer of amorphous carbon, has been investigated by transmission electron microscopy. It is established that thermal annealing at temperatures below the tin melting point (T{sub m}) does not lead to phase transitions with the formation of new crystalline oxide phases. At the same time, the films undergo structural changes: the average size of blocks in the substrate plane decreases compared to those in an as-deposited film. Thermal annealing in air at temperatures above the tin melting point leads to the formation of multiphase oxide structures and increases the average size of blocks and islands in the substrate plane. It is shown that preliminary thermal annealing in air at temperatures below T{sub m} hinders oxidation upon subsequent heat treatment.

  6. Optical diagnostic of bipolar electrical discharges in HCl, KCl, and KOH solutions

    NASA Astrophysics Data System (ADS)

    Miron, C.; Bratescu, M. A.; Saito, N.; Takai, O.

    2011-06-01

    In this work, the characteristics of the plasma generated in HCl, KCl, and KOH solutions were analyzed using electrical and optical diagnostic techniques. Electrical discharges were initiated between two tungsten electrodes. Current and voltage characteristics have shown the features of a spark discharge for all of the solutions used in the experiment. The reactive species identified in the optical emission spectra depended on the type of solution used to generate the plasma. The time evolution of the reactive species depended on the nature of the solution and on the polarity of the applied pulse. The absorption spectra of the OH radical (X2? ? A2?+) were acquired when the voltage pulses were applied to the electrodes, with the intensity being lower in the regions between the pulses. The OH radical density was highest for the HCl solution plasma (2 × 1017 cm-3) when positive voltage pulses were applied to the electrodes.

  7. Magnetic properties of Sr-ferrites synthesized in molten (NaCl+KCl) flux

    NASA Astrophysics Data System (ADS)

    Kim, Si-Dong; Kim, Jung-Sik

    2006-12-01

    The Sr-ferrite powders, SrFe12O19, were synthesized by the molten salt method using (NaCl+KCl) mixture. Particle morphology was homogeneous and hexagonal platelet like. Both particle size and thickness increased as the reaction temperature and time increased. The sintering density of Sr-ferrite magnet prepared with powders by the molten salt method showed the maximum value at the sintering temperature of 1200C. The magnetic properties of the Sr-ferrite magnet were investigated with various sintering temperatures. The maximum values of remanent magnetization ( ?r, 45 emu/g) and coercivity field ( Hcj, 298 kA/m) occurred at the sintering temperatures of 1150- 1200C. The Sr-ferrite magnet by a molten salt method showed higher remanent magnetization and coercivity field than those of the Sr-ferrite magnet prepared with the same starting materials by a conventional ceramic process.

  8. Dielectron production in Ar + KCl collisions at 1.76A GeV

    NASA Astrophysics Data System (ADS)

    Agakishiev, G.; Balanda, A.; Belver, D.; Belyaev, A.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; Dohrmann, F.; Dybczak, A.; Eberl, T.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gilardi, C.; Golubeva, M.; González-Díaz, D.; Guber, F.; Gumberidze, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Huck, P.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Krása, A.; Krizek, F.; Krücken, R.; Kuc, H.; Kühn, W.; Kugler, A.; Kurepin, A.; Lang, S.; Lange, J. S.; Lapidus, K.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Morinière, E.; Mousa, J.; Müntz, C.; Naumann, L.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wendisch, C.; Wisniowski, M.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.

    2011-07-01

    We present results on dielectron production in 40Ar+KCl collisions at 1.76A GeV. For the first time ? mesons could be reconstructed in a heavy-ion reaction at a bombarding energy which is well below the production threshold in free nucleon-nucleon collisions. The ? multiplicity has been extracted and compared to the yields of other particles, in particular of the ? meson. At intermediate e+e- invariant masses, we find a strong enhancement of the pair yield over a reference spectrum from elementary nucleon-nucleon reactions, suggesting the onset of nontrivial effects of the nuclear medium. Transverse-mass spectra and angular distributions have been reconstructed in three invariant mass bins. In the former unexpectedly large slopes are found for high-mass pairs. The latter, in particular the helicity-angle distributions, are largely consistent with expectations for a pair cocktail dominated at intermediate masses by ? Dalitz decays.

  9. Hydrothermal growth of amethyst and citrine in NaCl and KCl solutions

    NASA Astrophysics Data System (ADS)

    Hosaka, Masahiro; Taki, Sadao

    1983-12-01

    Natural quartz grows from solutions containing mainly Na +, K + and Cl - ions. In this experiment, the growth of synthetic quartz under the same growth conditions as those of natural quartz was attempted using NaCl and KCl solutions as a growth solution. As a result, colored quartz equivalent in quality and color tone to natural amethyst and citrine was obtained. The quartz grown from r-cut and R-cut plate seeds with iron added to the growth solution was colorless but ?-ray irradiation produced a purplish tint. The quartz grown from X-cut plate and Y-bar seeds had a yellowish tint. Although the depth of color increased in proportion to the amount of iron, it reached close to saturation with an iron concentration of approximately 90 ?g/ml solvent.

  10. Simulated Surface Potentials at the Vapor-Water Interface for the KCl Aqueous Electrolyte Solution

    SciTech Connect

    Wick, Collin D.; Dang, Liem X.; Jungwirth, Pavel

    2006-07-14

    Classical molecular dynamics simulations with polarizable potential models were carried out to quantitatively determine the effects of KCl salt concentrations on the electrostatic surface potentials of the vapor-liquid interface of water. To the best of our knowledge, the present work is the first calculation of the aqueous electrolyte surface potentials. Results showed that increased salt concentration enhanced the electrostatic surface potentials, in agreement with the corresponding experimental measurements. Furthermore, the decomposition of the potential drop into static charges and induced dipoles showed a very strong effect on the potential drop (an increase of {approx}1V per 1M) due to the double layers formed by KCl. However, this was mostly negated by the negative contribution from induced dipoles, resulting in a relatively small overall increase ({approx}0.05V per 1M) in potential drop with increased salt concentration. This work was supported by the Office of Basic Energy Sciences of the Department of Energy, in part by the Chemical Sciences program and in part by the Engineering and Geosciences Division. The Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy. The funding of the Center for Biomolecules and Complex Molecular Systems is provided by the Ministry of Education of the Czech Republic under the project number LC512. The work performed at the Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic was a part of the research project Z40550506 and via the NSF-funded Environmental Molecular Science Institute (grants CHE 0431512 and 0209719) is gratefully acknowledged.

  11. Effects of various dopants on NaCl and KCl glow curves

    NASA Astrophysics Data System (ADS)

    Davidson, A. T.; Kozakiewicz, A. G.; Derry, T. E.; Comins, J. D.; Suszynska, M.

    2004-06-01

    We have measured the thermoluminescence of a number of NaCl and KCl crystals following irradiation at ambient temperature with the same dose (10 kGy) of Co-60 ? rays. We compare the TL of pure samples and of samples doped with europium and calcium ions. In the case of NaCl, additional impurities (Ni, Pb, Sr and Cr) have been investigated. The effects of irradiation are determined using optical absorption and thermoluminescence. Factors investigated include the effects of different dopants on TL glow curves and the effects of thermal annealing samples at 400 °C before the irradiation. Changes in TL glow curves relating to changes in the state of aggregation of the impurities produced by pre-irradiation annealing are reported in this paper. Perhaps the most significant effect is a temperature shift of the main glow peak in pre-annealed compared to not pre-annealed samples in the case of Eu doped NaCl. The magnitude of the shift depends on the concentration of the Eu dopant. Shifts are also observed for Ni and Sr impurities in NaCl, but not for Ca and Cr impurities in NaCl. In the case of KCl, glow peaks generally occur at similar temperatures in doped samples and do not shift when doped samples are pre-annealed. Here the main effect of different impurities is to influence the size of the emission and not the structure of the glow curve. Results are discussed in terms of current theories of thermoluminescence.

  12. Schedule for Completion of NUS B.Sc. (Hons.) in Chemistry KCL M.Sc. in Forensic Science

    E-print Network

    Yao, Shao Q

    Schedule for Completion of NUS B.Sc. (Hons.) in Chemistry ­ KCL M.Sc. in Forensic Science 4000 module.) [4x4MCs=16 MCs] YEAR5 Semesters1&2 7BBFM125 Principles of Forensic Science [10]/{15} 7 in Chemistry 1 [4] MA1421 Basic Applied Mathematics for Sciences OR MA1102R Calculus [4] LSM1401 Fundamentals

  13. Elaboration and characterization of a KCl single crystal doped with nanocrystals of a Sb2O3 semiconductor

    NASA Astrophysics Data System (ADS)

    Bouhdjer, L.; Addala, S.; Chala, A.; Halimi, O.; Boudine, B.; Sebais, M.

    2013-04-01

    Undoped and doped KCl single crystals have been successfully elaborated via the Czochralski (Cz) method. The effects of dopant Sb2O3 nanocrystals on structural and optical properties were investigated by a number of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDAX) analysis, UV-visible and photoluminescence (PL) spectrophotometers. An XRD pattern of KCl:Sb2O3 reveals that the Sb2O3 nanocrystals are in the well-crystalline orthorhombic phase. The broadening of diffraction peaks indicated the presence of a Sb2O3 semiconductor in the nanometer size regime. The shift of absorption and PL peaks is observed near 334 nm and 360 nm respectively due to the quantum confinement effect in Sb2O3 nanocrystals. Particle sizes calculated from XRD studies agree fairly well with those estimated from optical studies. An SEM image of the surface KCl:Sb2O3 single crystal shows large quasi-spherical of Sb2O3 crystallites scattered on the surface. The elemental analysis from EDAX demonstrates that the KCl:Sb2O3 single crystal is slightly rich in oxygen and a source of excessive quantities of oxygen is discussed.

  14. Protons and light fragments in Ar+KCl at 1.76 AGeV measured with HADES

    NASA Astrophysics Data System (ADS)

    Schuldes, Heidi; Lorenz, Manuel; HADES-Collaboration

    2015-04-01

    We present transverse momentum spectra, rapidity distributions and multiplicities of protons, deuterons and tritons measured with the High Acceptance DiElectronSpectrometer HADES in the reaction Ar(1.76A GeV)+KCl. This completes the HADES data set measured in this reaction, comprising dielectronsand various lighter hadrons.

  15. KCl -Permeabilized Pancreatic Islets: An Experimental Model to Explore the Messenger Role of ATP in the Mechanism of Insulin Secretion

    PubMed Central

    Deeney, Jude T.; Corkey, Barbara E.

    2015-01-01

    Our previous work has demonstrated that islet depolarization with KCl opens connexin36 hemichannels in ?-cells of mouse pancreatic islets allowing the exchange of small metabolites with the extracellular medium. In this study, the opening of these hemichannels has been further characterized in rat islets and INS–1 cells. Taking advantage of hemicannels’opening, the uptake of extracellular ATP and its effect on insulin release were investigated. 70 mM KCl stimulated light emission by luciferin in dispersed rat islets cells transduced with the fire-fly luciferase gene: it was suppressed by 20 mM glucose and 50 ?M mefloquine, a specific connexin36 inhibitor. Extracellular ATP was taken up or released by islets depolarized with 70 mM KCl at 5 mM glucose, depending on the external ATP concentration. 1 mM ATP restored the loss of ATP induced by the depolarization itself. ATP concentrations above 5 mM increased islet ATP content and the ATP/ADP ratio. No ATP uptake occurred in non-depolarized or KCl-depolarized islets simultaneously incubated with 50 ?M mefloquine or 20 mM glucose. Extracellular ATP potentiated the secretory response induced by 70 mM KCl at 5 mM glucose in perifused rat islets: 5 mM ATP triggered a second phase of insulin release after the initial peak triggered by KCl-depolarization itself; at 10 mM, it increased both the initial, KCl-dependent, peak and stimulated a greater second phase of secretion than at 5 mM. These stimulatory effects of extracellular ATP were almost completely suppressed by 50 ?M mefloquine. The magnitude of the second phase of insulin release due to 5 mM extracellular ATP was decreased by addition of 5 mM ADP (extracellular ATP/ADP ratio = 1). ATP acts independently of KATP channels closure and its intracellular concentration and its ATP/ADP ratio seems to regulate the magnitude of both the first (triggering) and second (amplifying) phases of glucose-induced insulin secretion. PMID:26444014

  16. A Trafficking-Deficient Mutant of KCC3 Reveals Dominant-Negative Effects on K–Cl Cotransport Function

    PubMed Central

    Delpire, Eric

    2013-01-01

    The K–Cl cotransporter (KCC) functions in maintaining chloride and volume homeostasis in a variety of cells. In the process of cloning the mouse KCC3 cDNA, we came across a cloning mutation (E289G) that rendered the cotransporter inactive in functional assays in Xenopus laevis oocytes. Through biochemical studies, we demonstrate that the mutant E289G cotransporter is glycosylation-deficient, does not move beyond the endoplasmic reticulum or the early Golgi, and thus fails to reach the plasma membrane. We establish through co-immunoprecipitation experiments that both wild-type and mutant KCC3 with KCC2 results in the formation of hetero-dimers. We further demonstrate that formation of these hetero-dimers prevents the proper trafficking of the cotransporter to the plasma membrane, resulting in a significant decrease in cotransporter function. This effect is due to interaction between the K–Cl cotransporter isoforms, as this was not observed when KCC3-E289G was co-expressed with NKCC1. Our studies also reveal that the glutamic acid residue is essential to K–Cl cotransporter function, as the corresponding mutation in KCC2 also leads to an absence of function. Interestingly, mutation of this conserved glutamic acid residue in the Na+-dependent cation-chloride cotransporters had no effect on NKCC1 function in isosmotic conditions, but diminished cotransporter activity under hypertonicity. Together, our data show that the glutamic acid residue (E289) is essential for proper trafficking and function of KCCs and that expression of a non-functional but full-length K–Cl cotransporter might results in dominant-negative effects on other K–Cl cotransporters. PMID:23593405

  17. Development and study of cement and a phosphocalciques ceramic as medical use

    NASA Astrophysics Data System (ADS)

    Abbaoui, E.; Essaddek, A.; Mejdoubi, E.; Elansari, L. L.; Elgadi, M.; Hammouti, B.

    2005-03-01

    The hydroxyapatite (Ca{10}(PO{4})6(OH){2}) has a structure and a chemical composition very close to those of the mineral phase of calcified tissues. It is thus used for a long time in orthopedic and odontological surgery. In the past few years, cements which evolve toward the hydroxyapatite have been the object of several studies. This communication reports the synthesis and the study of new phosphocalcic cement, which evolves after hardening, towards a hydroxyapatite. The cement is composed of tricalcium phosphate a type (? -Ca{3}(PO{4})2), calcium hydroxide (Ca(OH){2}) and phosphoric acid (H{3}PO{4}). The sintering of hardened cement, leads to ceramics having a structure and chemical composition close to those of the bone's mineral phase. The trisodium phosphate is used as melting agent to increase the hardness of ceramics and to decrease the sintering temperature, without affecting the physicochemical properties of ceramics.

  18. The study of synthetic carbonate-hydroxyapatites and dental enamels by IR and derivatographic methods

    NASA Astrophysics Data System (ADS)

    Jónás, K.; Vassányi, I.; Ungvári, I.

    1980-06-01

    It is stated that all the synthetic carbonate-hydroxyapatites, produced with the reaction of H3PO4 and Ca(OH)2 solutions, are B type carbonate-apatites. The carbonate content of these is completely eliminated up to 900° C. In dental enamels taken from the healthy teeth of females, the carbonate ions occupy different positions ( A B type carbonate-apatite). Those which are parallel to axis c are decomposed only above 900° C. It was found that the natural ageing of dental enamels is in correlation with the different CO{3/2-}/H2O ratio measured in these samples. Similar differences were observed between enamels taken from different parts of the tooth and the dentin. The change of the apatite composition after fluoride painting has been established by infrared (IR), derivatographic and X-ray methods.

  19. Characterization of Nano-Hydroxyapatite Synthesized from Sea Shells Through Wet Chemical Method

    NASA Astrophysics Data System (ADS)

    Santhosh, S.; Prabu, S. Balasivanandha

    2012-10-01

    Nano-hydroxyapatite (HA) was synthesized by a wet chemical reaction using powdered sea shells (CaO) as starting material which was converted to calcium hydroxide (Ca(OH)2) and subsequently reacted with phosphoric acid (H3PO4). Initially raw sea shells (CaCO3) were thermally converted to amorphous calcium oxide by heat treatment. Two sets of experiments were done; in the first experiment, HA powder was dried in an electric furnace and in the second experiment, the reactants were irradiated in a domestic microwave oven followed by microwave drying. In each set of experiments, the concentrations of the reactants were decreased gradually. HA was synthesized by slow addition of phosphoric acid (H3PO4) in to calcium hydroxide (Ca(OH)2) maintaining the pH of the solution at 10 to avoid the formation of calcium deficient apatites. In both the experiments, Ca:P ratio of 1.67 was maintained for the reagents. The synthesized samples showed X-ray diffraction (XRD) patterns corresponding to hydroxyapatite. The wet chemical process with furnace drying resulted in HA particles of size 7-34 nm, whereas microwave irradiated process yielded HA particles of size 34-102 nm as evidenced from XRD analyses. The above experimental work done by wet chemical synthesis to produce HA powder from sea shells is a simple processing method at room temperature. Microwave irradiation leads to uniform crystallite sizes as evident from this study, at differing concentrations of the reactants and is a comparatively easy method to synthesize HA. The high resolution scanning electron microscopy (HRSEM)/transmission electron microscopic (TEM) analyses revealed the characteristic rod-shaped nanoparticles of HA for the present study.

  20. Role of Protein Kinase C? and Calcium Entry in KCl-Induced Vascular Smooth Muscle Calcium Sensitization and Feedback Control of Cellular Calcium Levels

    PubMed Central

    Ratz, Paul H.; Miner, Amy S.

    2009-01-01

    The degree of tonic force (F) maintenance induced in vascular smooth muscle upon K+ depolarization with 110 mM KCl can be greatly reduced by inhibition of rhoA kinase (ROCK). We explored the possibility that a protein kinase C (PKC) isotype may also play a role in causing KCl-induced Ca2+ sensitization. In isometric rings of rabbit artery, the PKC inhibitors, Go-6983 (3-[1-[3-(dimethylamino)propyl]-5-methoxy-1H-indol-3-yl]-4-(1H-indol-3-yl)-1H-pyrrole-2,5-dione), GF-109203X (2-[1-(3-dimethylaminopropyl)indol-3-yl]-3-(indol-3-yl) maleimide), and a cell-permeable (myristoylated) pseudosubstrate inhibitor of PKC? (PIPKC?) inhibited KCl-induced tonic F. A myristoylated pseudosubstrate inhibitor of PKC?/? that inhibited phorbol dibutyrate-induced F slightly potentiated KCl-induced tonic F and attenuated 30 mM KCl-induced F. Although the ROCK inhibitor, H-1152 [(S)-(+)-2-methyl-1-[(4-methyl-5-isoquinolinyl)-sulfonyl]-hexahydro-1H-1,4-diazepine dihydrochloride], reduced basal phosphorylation of myosin light-chain phosphatase-targeting subunit at Thr853 (MYPT1-pT853), 3 and 10 ?M GF-109203X inhibited only KCl-stimulated phosphorylation, not basal MYPT1-pT853. In fura-2-loaded tissues, GF-109203X and PIPKC? elevated basal [Ca2+]i (calcium) and potentiated KCl-induced tonic increases in calcium while reducing KCl-induced tonic increases in F. Blockade by nifedipine of Ca2+ entry through voltage-operated Ca2+ channels reduced KCl-induced Ca2+ sensitization and KCl-stimulated but not basal MYPT1-pT853. These data together support a model in which ROCK and PKC? are constitutively active and function in “resting” muscle to regulate the basal levels of MYPT1-pT853 and calcium, respectively. In this model, KCl-induced increases in calcium activate PKC? to feed forward and cause additional MYPT1-pT853 above that induced by constitutive ROCK, permitting Ca2+ sensitization and strong F maintenance. Active PKC? also feeds back to attenuate the degree of KCl-induced increases in calcium. PMID:19011165

  1. Dielectron production in Ar + KCl collisions at 1.76A GeV

    SciTech Connect

    Agakishiev, G.; Belyaev, A.; Chernenko, S.; Fateev, O.; Zanevsky, Y.; Balanda, A.; Dybczak, A.; Michalska, B.; Otwinowski, J.; Przygoda, W.; Salabura, P.; Trebacz, R.; Wisniowski, M.; Belver, D.; Cabanelas, P.; Castro, E.; Garzon, J. A.; Blanco, A.; Fonte, P.; Lopes, L.

    2011-07-15

    We present results on dielectron production in {sup 40}Ar+KCl collisions at 1.76A GeV. For the first time {omega} mesons could be reconstructed in a heavy-ion reaction at a bombarding energy which is well below the production threshold in free nucleon-nucleon collisions. The {omega} multiplicity has been extracted and compared to the yields of other particles, in particular of the {phi} meson. At intermediate e{sup +}e{sup -} invariant masses, we find a strong enhancement of the pair yield over a reference spectrum from elementary nucleon-nucleon reactions, suggesting the onset of nontrivial effects of the nuclear medium. Transverse-mass spectra and angular distributions have been reconstructed in three invariant mass bins. In the former unexpectedly large slopes are found for high-mass pairs. The latter, in particular the helicity-angle distributions, are largely consistent with expectations for a pair cocktail dominated at intermediate masses by {Delta} Dalitz decays.

  2. Optical diagnostic of bipolar electrical discharges in HCl, KCl, and KOH solutions

    SciTech Connect

    Miron, C.; Bratescu, M. A.; Takai, O.; Saito, N.

    2011-06-15

    In this work, the characteristics of the plasma generated in HCl, KCl, and KOH solutions were analyzed using electrical and optical diagnostic techniques. Electrical discharges were initiated between two tungsten electrodes. Current and voltage characteristics have shown the features of a spark discharge for all of the solutions used in the experiment. The reactive species identified in the optical emission spectra depended on the type of solution used to generate the plasma. The time evolution of the reactive species depended on the nature of the solution and on the polarity of the applied pulse. The absorption spectra of the OH radical (X{sup 2}{Pi}{yields} A{sup 2}{Sigma}{sup +}) were acquired when the voltage pulses were applied to the electrodes, with the intensity being lower in the regions between the pulses. The OH radical density was highest for the HCl solution plasma (2 x 10{sup 17} cm{sup -3}) when positive voltage pulses were applied to the electrodes.

  3. Polarization infrared spectroscopy study of quasi-orthorhombic acetylene thin films on KCl (100)

    SciTech Connect

    Vogt, Jochen

    2006-02-15

    The growth of ultrathin films of acetylene on KCl (100) single-crystal surfaces has been studied by means of low-energy electron diffraction (LEED) and polarization infrared spectroscopy (PIRS) in transmission geometry at 40 K. IR spectra in the region of the asymmetric stretch vibration {nu}{sub 3} and the asymmetric bending mode {nu}{sub 5} were recorded at different coverages. The PIRS spectra as well as the observed ({radical}(2)x{radical}(2))R45 deg. diffraction pattern with two glide planes are consistent with a parallel orientation of the molecules with respect to the surface as expected for the formation of the low-temperature orthorhombic phase of C{sub 2}H{sub 2}. A refined analysis of the infrared spectra within the dynamic dipole-dipole coupling approach confirms that the lateral orientation of the molecules within one layer is close to the T-shaped geometry favored by the intermolecular quadrupole-quadrupole interaction. Deviating from what was assumed in a previous study [J. P. Toennies et al., Phys. Rev. B 65, 165427 (2002)], the lateral orientation of the molecules in subsequent layers is not characteristic for the orthorhombic phase: essential features in the IR spectra point towards a statistical stacking arrangement of two inequivalent layer types within the films. A structural model is proposed, which is consistent with all available experimental results.

  4. Photo-stimulated luminescence of KCl:Eu under X-ray and ion irradiation

    NASA Astrophysics Data System (ADS)

    Hashima, M.; Koshimizu, M.; Asai, K.

    2009-12-01

    We compared the photo-stimulated luminescence (PSL) process of storage phosphor KCl:Eu under the irradiation of X-ray, 2.0 MeV H + ions and 2.0 MeV He + ions. The purpose of the irradiation of H + and He + ions was to mimic the irradiation effects of neutrons. In each case, it was revealed that F-centers were involved in the PSL process. We observed an entirely different fluence-dependent PSL behavior between the X-ray and the ion irradiation, whereas the behavior of the F-center absorption was quite similar. This difference was due to the different yields of the trapping sites for the electrons liberated from the F-centers, and the difference in the yield was ascribed to the difference in the excitation density. This result clearly indicated a marked difference in the PSL process under X-ray and neutron irradiations and indicated that the analysis of the PSL process under ion irradiation is highly important for the application of PSL phosphors to neutron radiography.

  5. Protein-salt binding data from potentiometric titrations of lysozyme in aqueous solutions containing KCl

    SciTech Connect

    Engmann, J.; Blanch, H.W.; Prausnitz, J.M. |

    1997-03-01

    An existing method for potentiometric titrations of proteins was improved, tested and applied to titrations of the enzyme hen-egg-white lysozyme in aqueous solutions containing KCl at ionic strengths from 0.1 M to 2.0 M at 25 C. Information about the protein`s net charge dependence on pH and ionic strength were obtained and salt binding numbers for the system were calculated using a linkage concept. For the pH range 2.5--11.5, the net charge slightly but distinctly increases with increasing ionic strength between 0.1 M and 2.0 M. The differences are most distinct in the pH region below 5. Above pH 11.35, the net charge decreases with increasing ionic strength. Preliminary calculation of binding numbers from titration curves at 0.1 M and 1.0 M showed selective association of chloride anions and expulsion of potassium ions at low pH. Ion-binding numbers from this work will be used to evaluate thermodynamic properties and to correlate crystallization or precipitation phase-equilibrium data in terms of a model based on the integral-equation theory of fluids which is currently under development.

  6. ?-p femtoscopy in collisions of Ar+KCl at 1.76A GeV

    NASA Astrophysics Data System (ADS)

    Agakishiev, G.; Balanda, A.; Bassini, R.; Belver, D.; Belyaev, A. V.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Braun-Munzinger, P.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; Díaz, J.; Dohrmann, F.; Dybczak, A.; Eberl, T.; Fabbietti, L.; Fateev, O. V.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gil, A.; Gilardi, C.; Golubeva, M.; González-Díaz, D.; Guber, F.; Hennino, T.; Holzmann, R.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Krizek, F.; Krücken, R.; Kühn, W.; Kugler, A.; Kurepin, A.; Lang, S.; Lange, J. S.; Lapidus, K.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Morinière, E.; Mousa, J.; Müntz, C.; Naumann, L.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy-Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Sudol, M.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wendisch, C.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y. V.; Zhou, P.; Zumbruch, P.

    2010-08-01

    Results on ?p femtoscopy are reported at the lowest energy so far. At a beam energy of 1.76A GeV, the reaction Ar+KCl was studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. A high-statistics and high-purity ? sample was collected, allowing for the investigation of ?p correlations at low relative momenta. The experimental correlation function is compared to corresponding model calculations allowing the determination of the space-time extent of the ?p emission source. The ?p source radius is found to be slightly smaller than the pp correlation radius for a similar collision system. The present ?p radius is significantly smaller than that found for Au+Au/Pb+Pb collisions in the AGS, SPS, and RHIC energy domains but larger than that observed for electroproduction from He. Taking into account all available data, we find the ?p source radius to increase almost linearly with the number of participants to the power of one-third.

  7. Thermite and Fe/KClO/sub 4/: some thermodynamic calculations

    SciTech Connect

    Woods, C.M.

    1984-01-01

    Heats of reaction were calculated for thermite materials consisting of various mixtures of Al, Al/Si, Fe/sub 2/O/sub 3/, and Ni. The primary reaction taking place in these thermites was the reduction of iron oxide by aluminum to form metallic iron and aluminum oxide. It was demonstrated that by taking into account all of the favored secondary reactions, the excess thermal output could be accounted for. Adiabatic flame temperatures were calculated. Average heat capacities were calculated for the temperature ranges from ambient to the AFT. Heat capacity calculations were also made in an attempt to understand the relationship between pole temperature and calorific output of various thermite and Fe/KClO/sub 4/ components. Adiabatic flame temperatures were calculated using, as a closed system, the thermite material and its container. An empirical heat loss was subtracted from the available enthalpy of reaction. The remainder of the available heat was then used to calculate the system reduced adiabatic flame temperature which was termed the pole temperature projection. The results of these calculations were quite good when compared to actual measured values. Necessary heat losses were then calculated in the same fashion to fit the experimentally determined pole temperatures to a reduced AFT.

  8. First-Principles Calculation of Principal Hugoniot and K-Shell X-ray Absorption Spectra for Warm Dense KCl

    E-print Network

    Zhao, Shijun; Kang, Wei; Li, Zi; Zhang, Ping; He, Xian-Tu

    2015-01-01

    Principal Hugoniot and K-shell X-ray absorption spectra of warm dense KCl are calculated using the first-principles molecular dynamics method. Evolution of electronic structures as well as the influence of the approximate description of ionization on pressure (caused by the underestimation of the energy gap between conduction bands and valence bands) in the first-principles method are illustrated by the calculation. Pressure ionization and thermal smearing are shown as the major factors to prevent the deviation of pressure from global accumulation along the Hugoniot. In addition, cancellation between electronic kinetic pressure and virial pressure further reduces the deviation. The calculation of X-ray absorption spectra shows that the band gap of KCl persists after the pressure ionization of the $3p$ electrons of Cl and K taking place at lower energy, which provides a detailed understanding to the evolution of electronic structures of warm dense matter.

  9. Transmission Line Modeling Applied to Hot Corrosion of Fe-40at.pctAl in Molten LiCl-KCl

    NASA Astrophysics Data System (ADS)

    Barraza-Fierro, Jesus Israel; Espinosa-Medina, Marco Antonio; Castaneda, Homero

    2015-12-01

    The effect of Cu and Li additions to the intermetallic alloy Fe-40at.pctAl on the corrosion performance in an LiCl-55wtpctKCl molten eutectic salt was studied by means of electrochemical impedance spectroscopy, transmission line modeling (TLM), and cathodic polarization. The tests were done at 723 K, 773 K, and 823 K (450 °C, 500 °C, and 550 °C), for 60 and 720 minutes. The element additions could improve the corrosion resistance of Fe-40at.pctAl in molten LiCl-KCl, while TLM could characterize and quantify the interfacial processes in hot corrosion. The polarization curves helped to establish the possible cathodic reactions in the experimental conditions.

  10. Stimulation of neurite outgrowth in PC12 cells by EGF and KCl depolarization: a Ca(2+)-independent phenomenon

    PubMed Central

    1995-01-01

    MAP kinase activity is necessary for growth factor induction of neurite outgrowth in PC12 cells. Although NGF and EGF both stimulate MAP kinase activity, EGF does not stimulate neurite extension. We report that EGF, in combination with KCl, stimulates neurite outgrowth in PC12 cells. This phenomenon was independent of intracellular Ca2+ increases and not due to enhancement of MAP kinase activity over that seen with EGF alone. However, EGF plus KCl increased intracellular cAMP, and other cAMP elevating agents acted synergistically with EGF to promote neurite outgrowth. Stimulation of neurite outgrowth by cAMP and EGF was blocked by inhibitors of transcription suggesting that synergistic regulation of transcription by the cAMP and MAP kinase pathways may stimulate neurite growth. PMID:7622569

  11. Recycling of LiCl-KCl eutectic based salt wastes containing radioactive rare earth oxychlorides or oxides

    NASA Astrophysics Data System (ADS)

    Eun, H. C.; Cho, Y. Z.; Son, S. M.; Lee, T. K.; Yang, H. C.; Kim, I. T.; Lee, H. S.

    2012-01-01

    Recycling of LiCl-KCl eutectic salt wastes containing radioactive rare earth oxychlorides or oxides was studied to recover renewable salts from the salt wastes and to minimize the radioactive wastes by using a vacuum distillation method. Vaporization of the LiCl-KCl eutectic salt was effective above 900 °C and at 5 Torr. The condensations of the vaporized salt were largely dependent on temperature gradient. Based on these results, a recycling system of the salt wastes as a closed loop type was developed to obtain a high efficiency of the salt recovery condition. In this system, it was confirmed that renewable salt was recovered at more than 99 wt.% from the salt wastes, and the changes in temperature and pressure in the system could be utilized to understand the present condition of the system operation.

  12. First-principles calculation of principal Hugoniot and K-shell X-ray absorption spectra for warm dense KCl

    NASA Astrophysics Data System (ADS)

    Zhao, Shijun; Zhang, Shen; Kang, Wei; Li, Zi; Zhang, Ping; He, Xian-Tu

    2015-06-01

    Principal Hugoniot and K-shell X-ray absorption spectra of warm dense KCl are calculated using the first-principles molecular dynamics (FPMD) method. Evolution of electronic structures as well as the influence of the approximate description of ionization on pressure (caused by the underestimation of the energy gap between conduction bands and valence bands) in the first-principles method are illustrated by the calculation. It is shown that approximate description of ionization in FPMD has small influence on Hugoniot pressure due to mutual compensation of electronic kinetic pressure and virial pressure. The calculation of X-ray absorption spectra shows that the band gap of KCl persists after the pressure ionization of the 3p electrons of Cl and K taking place at lower energy, which provides a detailed understanding to the evolution of electronic structures of warm dense matter.

  13. Real-Time X-Ray Diffraction Measurements of the Phase Transition in KCl Shocked along [100

    SciTech Connect

    D'Almeida, T.; Gupta, Y. M.

    2000-07-10

    X-ray diffraction measurements and analyses were developed and used to examine the phase transition in KCl shocked to 7 GPa. Diffraction data were obtained below and above the transition stress, and related quantitatively to macroscopic compression in the two phases. Interplanar spacing measurements revealed isotropic compression of the unit cell. Above the transition stress, a diffraction peak from the (110) planes in phase II was observed consistently and the orientation of the transformed crystal structure was determined with respect to the phase I structure. This determination provides a mechanism for the atomic rearrangement from the rocksalt to the cesium chloride structure in KCl shocked along [100]. (c) 2000 The American Physical Society.

  14. An upper limit on hypertriton production in collisions of Ar(1.76 A GeV) + KCl

    NASA Astrophysics Data System (ADS)

    Agakishiev, G.; Belver, D.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Castro, E.; Chernenko, S.; Destefanis, M.; Dohrmann, F.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gilardi, C.; Golubeva, M.; González-Díaz, D.; Guber, F.; Gumberidze, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Krása, A.; Krizek, F.; Krücken, R.; Kuc, H.; Kühn, W.; Kugler, A.; Kurepin, A.; Lang, S.; Lange, J. S.; Lapidus, K.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Morinière, E.; Mousa, J.; Müntz, C.; Naumann, L.; Pachmayer, Y. C.; Palka, M.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Rehnisch, L.; Reshetin, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Scheib, T.; Schmah, A.; Schuldes, H.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wendisch, C.; Wisniowski, M.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.

    2013-11-01

    A high-statistic data sample of Ar(1.76 AGeV)+KCl events recorded with HADES is used to search for a hypertriton signal. An upper production limit per centrality-triggered event of on the 3 level is derived. Comparing this value with the number of successfully reconstructed hyperons allows to determine an upper limit on the ratio , which is confronted with statistical and coalescence-type model calculations.

  15. Preparation of Al-La Master Alloy by Thermite Reaction in NaF-NaCl-KCl Molten Salt

    NASA Astrophysics Data System (ADS)

    Jang, Poknam; Li, Hyonmo; Kim, Wenjae; Wang, Zhaowen; Liu, Fengguo

    2015-05-01

    A NaF-NaCl-KCl ternary system containing La2O3 was investigated for the preparation of Al-La master alloy by the thermite reaction method. The solubility of La2O3 in NaF-NaCl-KCl molten salt was determined by the method of isothermal solution saturation. Inductively coupled plasma-optical emission spectroscopy and x-ray diffraction (XRD) analyses were used to consider the content of La2O3 in molten salt and the supernatant composition of molten salt after dissolution of La2O3, respectively. The results showed that the content of NaF had a positive influence on the solubility of La2O3 in NaF-NaCl-KCl molten salts, and the solubility of La2O3 could reach 8.71 wt.% in molten salts of 50 wt.%NaF-50 wt.% (44 wt.%NaCl + 56 wt.%KCl). The XRD pattern of cooling molten salt indicated the formation of LaOF in molten salt, which was probably obtained by the reaction between NaF and La2O3. The kinetic study showed that the thermite reaction was in accord with a first-order reaction model. The main influence factors on La content in the Al-La master alloy product, including molten salt composition, amount of Al, concentration of La2O3, stirring, reduction time and temperature, were investigated by single-factor experimentation. The content of La in the Al-La master alloy could be reached to 10.1 wt.%.

  16. Epitaxial growth of Ge-Sb-Te films on KCl by high deposition rate pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Thelander, E.; Gerlach, J. W.; Ross, U.; Frost, F.; Rauschenbach, B.

    2014-06-01

    Pulsed laser deposition was employed to deposit epitaxial Ge2Sb2Te5-layers (GST) on (100) oriented KCl-substrates. XRD-measurements show a process temperature window for epitaxial growth of the cubic phase between 200 and 300 °C. Below 250 °C (111) oriented GST dominates the growth process and above 250 °C the (100) orientation is the dominating one. Pole figure measurements confirm these results and additionally reveal that the (111) orientation consists of 4 domains with 90° azimuthal separation with an initial 15° rotation with the substrate lattice, i.e., [2-1-1]GST || [100]KCl. The (100) orientation grows cube-on-cube with KCl. A systematic variation of the deposition rate showed that it is possible to obtain epitaxial films in the range between 2.5 and 250 nm/min with no significant deterioration of crystal quality. A smooth topography of (111) oriented films was found, whereas the (100) dominated films in general show higher surface roughness as evidenced from atomic force microscopy investigations.

  17. Vacuum evaporation of KCl-NaCl salts. Part 2: Vaporization-rate model and experimental results

    SciTech Connect

    Wang, L.L.; Wallace, T.C. Sr.; Hampel, F.G.; Steele, J.H.

    1996-06-01

    Separation of chloride salts from the actinide residue by vacuum evaporation is a promising method of treating wastes from the pyrochemical plutonium processes. A model based on the Hertz-Langmuir relation is used to describe how evaporation rates of the binary KCl-NaCl system change with time. The effective evaporation coefficient ({alpha}), which is a ratio of the actual evaporation rate to the theoretical maximum, was obtained for the KCl-NaCl system using this model. In the temperature range of 640 C to 760 C, the effective evaporation coefficient ranges from {approximately}0.4 to 0.1 for evaporation experiments conducted at 0.13 Pa. At temperatures below the melting point, the lower evaporation coefficients are suggested to result from the more complex path that a molecule needs to follow before escaping to the gas phase. At the higher liquid temperatures, the decreasing evaporation coefficients result from a combination of the increasing vapor-flow resistances and the heat-transfer effects at the evaporation surface and the condensate layer. The microanalysis of the condensate verified that composition of the condensate changes with time, consistent with the model calculation. The microstructural examination revealed that the vaporate may have condensed as a single solution phase, which upon cooling forms fine lamellar structures of the equilibrium KCl and NaCl phases. In conclusion, the optimum design of the evaporation process and equipment must take the mass and heat transfer factors and equipment materials issues into consideration.

  18. Package FLUIDS. Part 4: thermodynamic modelling and purely empirical equations for H2O-NaCl-KCl solutions

    NASA Astrophysics Data System (ADS)

    Bakker, Ronald J.

    2012-05-01

    A H2O-NaCl-KCl-rich fluid occurs occasionally in fluid inclusions in a variety of geological environments. The properties of this fluid provide information about the conditions of entrapment, and thereby, conditions that have affected the rock. New purely empirical and thermodynamic models are developed in this study to reproduce the properties of the H2O-NaCl-KCl fluid system, especially the liquidus at variable pressures (the solid-liquid-vapour surface, i.e. SLV), and at constant pressures (the solid-liquid surface, i.e. SL). The SLV surface is modelled according to "best-fit" polynomial equations, which relate temperature, pressure and composition. The SL surfaces, at constants pressures, are modelled according to thermodynamic principles, i.e. the equality of chemical potentials of components (NaCl and KCl) in each phase at equilibrium. The models are valid up to 400 MPa and 900°C and can be applied to fluid inclusions studies to obtain salinities from dissolution temperatures of salt crystals. The new models are included in the program AqSo WHS that forms part of the software package FLUIDS (Bakker, Chem Geol 194:3-23, 2003), to be able to apply directly the mathematical functions in fluid inclusion studies and in general fluid properties investigations.

  19. Electrolysis of uranium nitride containing fission product elements (Mo, Pd, Nd) in a molten LiCl-KCl eutectic

    SciTech Connect

    Satoh, Takumi; Iwai, Takashi; Arai, Yasuo

    2007-07-01

    The electrolysis of burnup-simulated uranium nitride, UN, containing representative solid fission product elements (Mo, Pd, Nd) was investigated in the molten LiCl-KCl eutectic salt with 0.54 wt% UCl{sub 3} from the view point of application of pyrochemical reprocessing to nitride fuel cycle. It was found from cyclic voltammetry and anodic polarization curve measurement that anodic dissolution of UN began at about -0.75 V vs. Ag/AgCl reference electrode in all samples. After the electrolysis at the constant anodic potential of -0.65 {approx} -0.60 V vs. Ag/AgCl, most of UN was dissolved into LiCl- KCl as UCl{sub 3} at the anode, and U was recovered in the liquid Cd cathode in all samples. Further, Nd was dissolved into LiCl-KCl as NdCl{sub 3}, while Mo and Pd were not dissolved but remained at the anode. (authors)

  20. Physiologically relevant concentrations of NaCl and KCl increase DNA photocleavage by an N-substituted 9-aminomethylanthracene dye.

    PubMed

    Terry, Carla A; Fernández, María-José; Gude, Lourdes; Lorente, Antonio; Grant, Kathryn B

    2011-11-29

    This paper describes the synthesis of a new 9-aminomethylanthracene dye N-substituted with a pyridinylpolyamine side chain (4). The effects of NaCl and KCl on anthracene/DNA interactions were then studied, with the goal of simulating the conditions of high ionic strength that a DNA photosensitizer might encounter in the cell nucleus (~150 mM of NaCl and 260 mM of KCl). As exemplified by methylene blue (5), the expected effect of increasing ionic strength is to decrease DNA binding and photocleavage yields. In contrast, the addition of 150 mM of NaCl in combination with 260 mM of KCl to photocleavage reactions containing micromolar concentrations of 4 triggers the conversion of supercoiled, nicked, and linear forms of pUC19 plasmid into a highly degraded band of DNA fragments (350 nm h?, pH 7.0). Circular dichroism spectra point to a correlation between salt-induced unwinding of the DNA helix and the increase in DNA photocleavage yields. The results of circular dichroism, UV-vis absorption, fluorescence emission, thermal denaturation, and photocleavage inhibition experiments suggest that the combination of salts causes a change in the DNA binding mode of 4 from intercalation to an external interaction. This in turn leads to an increase in the anthracene-sensitized production of DNA-damaging reactive oxygen species. PMID:22014335

  1. An optimal method for phosphorylation of rare earth chlorides in LiCl-KCl eutectic based waste salt

    NASA Astrophysics Data System (ADS)

    Eun, H. C.; Kim, J. H.; Cho, Y. Z.; Choi, J. H.; Lee, T. K.; Park, H. S.; Park, G. I.

    2013-11-01

    A study on an optimal method for the phosphorylation of rare earth chlorides in LiCl-KCl eutectic waste salt generated the pyrochemical process of spent nuclear fuel was performed. A reactor with a pitched four blade impeller was designed to create a homogeneous mixing zone in LiCl-KCl eutectic salt. A phosphorylation test of NdCl3 in the salt was carried out by changing the operation conditions (operation temperature, stirring rate, agent injection amount). Based on the results of the test, a proper operation condition (450 °C, 300 rpm, 1 eq. of phosphorylation agent) for over a 0.99 conversion ratio of NdCl3 to NdPO4 was determined. Under this condition, multi-component rare earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Y) chlorides were effectively converted into phosphate forms. It was confirmed that the existing regeneration process of LiCl-KCl eutectic waste salt can be greatly improved and simplified through these phosphorylation test results.

  2. Kinetics of desorption of KCL from polyvinyl alcohol-borate hydrogel in aqueous-alcoholic solvents at different temperatures

    NASA Astrophysics Data System (ADS)

    Saeed, Rehana; Abdeen, Zain Ul

    2015-11-01

    Desorption kinetics of adsorbed KCl from Polyvinyl alcohol borate hydrogel was studied by conductivity method in aqueous system and aqueous binary solvent system using 50% aqueous-methanol, aqueous- ethanol and aqueous-propanol at different temperature ranging from 293 to 313 K. Desorption process follows pseudo first order and intra particle diffusion kinetics was analyzed on the basis of linear regression coefficient R 2 and chi square test ?2 values. The process of desorption of KCl from hydrogel was favorable in aqueous system, the study reveals the fact that the polarity of solvent influenced the kinetics of desorption, on decrement of polarity of solvent rate, rate constant and intra particle rate constant decreases. Based on intra particle kinetic equation fitting it was concluded that desorption was initiated by removal of ions from surface of hydrogel later on ions interacted inside the cross linked unit was also become free. Temperature enhances the rate, rate constant and intra particle rate constant. Thermodynamic parameters attributed towards the fact that the process of desorption of KCl from hydrogel is non-spontaneous in nature.

  3. The effect of substitution of NaCl with KCl on chemical composition and functional properties of low-moisture Mozzarella cheese.

    PubMed

    Ayyash, M M; Shah, N P

    2011-08-01

    The effect of NaCl substitution with KCl on chemical composition, organic acids profile, soluble calcium, and functionality of low-moisture Mozzarella cheese (LMMC) was investigated. Functionality (meltability and browning), organic acids profile, and chemical composition were determined. Chemical composition showed no significant difference between experimental cheeses at same storage period, and same salt treatment. Meltability of LMMC salted with 3NaCl:1KCl, 1NaCl:1KCl, and 1NaCl:3KCl was higher compared with only NaCl (control). The amount of soluble Ca and P increased significantly during storage, with no significant difference between salt treatments. Organic acids profile did not differ between salt treatments at the same storage time. PMID:21787912

  4. In situ measurement technique for simultaneous detection of K, KCl, and KOH vapors released during combustion of solid biomass fuel in a single particle reactor.

    PubMed

    Sorvajärvi, Tapio; DeMartini, Nikolai; Rossi, Jussi; Toivonen, Juha

    2014-01-01

    A quantitative and simultaneous measurement of K, KCl, and KOH vapors from a burning fuel sample combusted in a single particle reactor was performed using collinear photofragmentation and atomic absorption spectroscopy (CPFAAS) with a time resolution of 0.2 s. The previously presented CPFAAS technique was extended in this work to cover two consecutive fragmentation pulses for the photofragmentation of KCl and KOH. The spectral overlapping of the fragmentation spectra of KCl and KOH is discussed, and a linear equation system for the correction of the spectral interference is introduced. The detection limits for KCl, KOH, and K with the presented measurement arrangement and with 1 cm sample length were 0.5, 0.1, and 0.001 parts per million, respectively. The experimental setup was applied to analyze K, KCl, and KOH release from 10 mg spruce bark samples combusted at the temperatures of 850, 950, and 1050 °C with 10% of O2. The combustion experiments provided data on the form of K vapors and their release during different combustion phases and at different temperatures. The measured release histories agreed with earlier studies of K release. The simultaneous direct measurement of atomic K, KCl, and KOH will help in the impact of both the form of K in the biomass and fuel variables, such as particle size, on the release of K from biomass fuels. PMID:24480273

  5. Current view on the functional regulation of the neuronal K+-Cl? cotransporter KCC2

    PubMed Central

    Medina, Igor; Friedel, Perrine; Rivera, Claudio; Kahle, Kristopher T.; Kourdougli, Nazim; Uvarov, Pavel; Pellegrino, Christophe

    2014-01-01

    In the mammalian central nervous system (CNS), the inhibitory strength of chloride (Cl?)-permeable GABAA and glycine receptors (GABAAR and GlyR) depends on the intracellular Cl? concentration ([Cl?]i). Lowering [Cl?]i enhances inhibition, whereas raising [Cl?]i facilitates neuronal activity. A neuron's basal level of [Cl?]i, as well as its Cl? extrusion capacity, is critically dependent on the activity of the electroneutral K+-Cl? cotransporter KCC2, a member of the SLC12 cation-Cl? cotransporter (CCC) family. KCC2 deficiency compromises neuronal migration, formation and the maturation of GABAergic and glutamatergic synaptic connections, and results in network hyperexcitability and seizure activity. Several neurological disorders including multiple epilepsy subtypes, neuropathic pain, and schizophrenia, as well as various insults such as trauma and ischemia, are associated with significant decreases in the Cl? extrusion capacity of KCC2 that result in increases of [Cl?]i and the subsequent hyperexcitability of neuronal networks. Accordingly, identifying the key upstream molecular mediators governing the functional regulation of KCC2, and modifying these signaling pathways with small molecules, might constitute a novel neurotherapeutic strategy for multiple diseases. Here, we discuss recent advances in the understanding of the mechanisms regulating KCC2 activity, and of the role these mechanisms play in neuronal Cl? homeostasis and GABAergic neurotransmission. As KCC2 mediates electroneutral transport, the experimental recording of its activity constitutes an important research challenge; we therefore also, provide an overview of the different methodological approaches utilized to monitor function of KCC2 in both physiological and pathological conditions. PMID:24567703

  6. Measurements and Analysis of Oxygen Bubble Distributions in LiCl-KCl Molten Salt

    SciTech Connect

    Ryan W. Bezzant; Supathorn Phongikaroon; Michael F. Simpson

    2013-03-01

    Transparent system experimental studies have been performed to provide measurement and analysis of oxygen bubble distributions and mass transfer coefficients at different sparging rates ranging from 0.05 to 0.20 L/min in LiCl-KCl molten salt at 500 degrees C using a high-speed digital camera and an oxygen sensor. The results reveal that bubble sizes and rise velocities increased with an increase in oxygen sparging rate. The bubbles observed were ellipsoidal in shape, and an equivalent diameter based on the ellipsoid volume was calculated. The average equivalent bubble diameters at 500 degrees C and these oxygen sparging rates range from 2.63 to 4.07 mm. Results show that the bubble equivalent diameters at each respective sparging rate are normally distributed. A Fanning friction factor correlation was produced to predict a bubble’s rise velocity based on its equivalent diameter. The oxygen mass transfer coefficients for four sparging rates were calculated using the oxygenation model. These calculated values were within the order of magnitude of 10-2 cm/sec and followed a decreasing trend corresponding to an increasing bubble size and sparging rate. The diffusivities were calculated based on two different types of mechanisms, one based on physics of the bubbles and the other on systematic properties. The results reveal that diffusivity values calculated from bubble physics are 1.65 to 8.40 x 10-5 cm2/sec, which are within the range suggested by literature for gases in liquids of a similar viscosity.

  7. Purification of used eutectic (LiCl-KCl) salt electrolyte from pyroprocessing

    NASA Astrophysics Data System (ADS)

    Cho, Yung-Zun; Lee, Tae-Kyo; Eun, Hee-Chul; Choi, Jung-Hoon; Kim, In-Tae; Park, Geun-Il

    2013-06-01

    The separation characteristics of surrogate rare-earth fission products in a eutectic (LiCl-KCl) molten salt were investigated. This system is based on the eutectic salt used for the pyroprocessing treatment of used nuclear fuel (UNF). The investigation was performed using an integrated rare-earth separation apparatus comprising a precipitation reactor, a solid detachment device, and a layer separation device. To separate rare-earth fission products, a phosphate precipitation method using both Li3PO4 and K3PO4 as a precipitant was performed. The use of an equivalent phosphate precipitant composed of 0.408 molar ratio-K3PO4 and 0.592 molar ratio-Li3PO4 can preserve the original eutectic ratio, LiCl-0.592 molar ratio (or 45.2 wt%), as well as provide a high separation efficiency of over 99.5% under conditions of 550 °C and Ar sparging when using La, Nd, Ce, and Pr chlorides. The mixture of La, Nd, Ce, and Pr phosphate had a typical monoclinic (or monazite) structure, which has been proposed as a reliable host matrix for the permanent disposal of a high-level waste form. To maximize the reusability of purified eutectic waste salt after rare-earth separation, the successive rare-earth separation process, which uses both phosphate precipitation and an oxygen sparging method, were introduced and tested with eight rare-earth (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) chlorides. In the successive rare-earth separation process, the phosphate reaction was terminated within 1 h at 550 °C, and a 4-8 h oxygen sparging time were required to obtain over a 99% separation efficiency at 700-750 °C. The mixture of rare-earth precipitates separated by the successive rare-earth separation process was found to be phosphate, oxychloride, and oxide. Through the successive rare-earth separation process, the eutectic ratio of purified salt maintained its original value, and impurity content including the residual precipitant of purified salt can be minimized.

  8. EXPLORING IO'S ATMOSPHERIC COMPOSITION WITH APEX: FIRST MEASUREMENT OF {sup 34}SO{sub 2} AND TENTATIVE DETECTION OF KCl

    SciTech Connect

    Moullet, A.; Lellouch, E.; Moreno, R.; Gurwell, M.; Black, J. H; Butler, B.

    2013-10-10

    The composition of Io's tenuous atmosphere is poorly constrained. Only the major species SO{sub 2} and a handful of minor species have been positively identified, but a variety of other molecular species should be present, based on thermochemical equilibrium models of volcanic gas chemistry and the composition of Io's environment. This paper focuses on the spectral search for expected yet undetected molecular species (KCl, SiO, S{sub 2}O) and isotopes ({sup 34}SO{sub 2}). We analyze a disk-averaged spectrum of a potentially line-rich spectral window around 345 GHz, obtained in 2010 at the APEX 12 m antenna. Using different models assuming either extended atmospheric distributions or a purely volcanically sustained atmosphere, we tentatively measure the KCl relative abundance with respect to SO{sub 2} and derive a range of 4 × 10{sup –4}-8 × 10{sup –3}. We do not detect SiO or S{sub 2}O and present new upper limits on their abundances. We also present the first measurement of the {sup 34}S/{sup 32}S isotopic ratio in gas phase on Io, which appears to be twice as high as the Earth and interstellar medium reference values. Strong lines of SO{sub 2} and SO are also analyzed to check for longitudinal variations of column density and relative abundance. Our models show that, based on their predicted relative abundance with respect to SO{sub 2} in volcanic plumes, both the tentative KCl detection and SiO upper limit are compatible with a purely volcanic origin for these species.

  9. Absorption characteristics of anions (I-, Br-, and Te2-) into zeolite in molten LiCl-KCl eutectic salt

    NASA Astrophysics Data System (ADS)

    Uozumi, Koichi; Sugihara, Kei; Kinoshita, Kensuke; Koyama, Tadafumi; Tsukada, Takeshi; Terai, Takayuki; Suzuki, Akihiro

    2014-04-01

    The behaviors of anion fission product (FP) elements to be absorbed into zeolite in molten LiCl-KCl eutectic salt were studied using iodine, bromine, and tellurium. First, the type-A zeolite was selected as the most suitable type of zeolite among type-A, type-X, and type-Y zeolites through experiments in which zeolites were heated together with LiCl-KCl-KI salt. As the next step, experiments in which the type-A zeolite was immersed in molten LiCl-KCl salt containing various concentrations of iodine, bromine, or tellurium were performed. The degree of absorption of the anion FP elements was evaluated using the separation factor (SF) value versus chlorine. Although the SF values for iodine and tellurium were higher than 1.0, which meant that these elements were absorbed into the type-A zeolite more intensively than chlorine in the salt, the corresponding value for bromine was approximately 1.0. The effects of coexisting cation FPs were also examined using cesium, strontium, and neodymium, and it was revealed that the SF values for iodine were less than those in the case without cation addition. On the other hand, the SF values for tellurium were not affected by the coexistence of cesium and strontium. Finally, the feasibility of the present pyroprocess flowsheet was evaluated by calculating the inventory of each anion FP in an electrorefiner based on the obtained SF values instead of temporary values for the anion FPs absorption, which were set due to lack of experimental data.

  10. Electrochemistry and Spectroelectrochemistry of Europium(III) chloride in 3 LiCl – 2KCl from 643 to 1123 K

    SciTech Connect

    Schroll, Cynthia A.; Chatterjee, Sayandev; Levitskaia, Tatiana G.; Heineman, William R.; Bryan, Samuel A.

    2013-09-09

    The electrochemical and spectroelectrochemical behavior of Europium(III) chloride in a molten salt eutectic, 3 LiCl – 2 KCl, over a temperature range of 643 – 1123 K using differential pulse voltammetry, cyclic voltammetry, potential step chronoabsorptometry, and thin-layer spectroelectrochemistry is reported. The electrochemical reaction was determined to be the one electron reduction of Eu3+ to Eu2+ at all temperatures. The redox potential of Eu3+/2+ shifts to more positive potentials and the diffusion coefficient for Eu3+ increases as temperature increases. The results for the number of electrons transferred, redox potential and diffusion coefficient are in good agreement between the electrochemical and spectroelectrochemical techniques.

  11. Transport of ions across bipolar membranes. 1. Theoretical and experimental examination of the membrane potential of KCl solutions

    SciTech Connect

    Higa, Mitsuru; Kira, Akira

    1995-04-06

    A calculation method was derived for ionic transport across a bipolar membrane in dialysis systems of mixed salt solutions containing multivalent ions. The calculation of the total membrane potential in the solutions containing KCl alone by this method shows that the potential-salt concentration curve depends both on the direction of the arrangement of the membrane charged layers to the concentration gradient of the salt solutions and on the ratio of the charge densities of the two charged layers. The simulations based on experimentally determined parameters agree with the potential measurements for bipolar membranes produced so that the transport properties depend mainly on their charges. 40 refs., 4 figs., 1 tab.

  12. Deep sub-threshold $?^-$ production in Ar+KCl reactions at 1.76A GeV

    E-print Network

    G. Agakishiev; A. Balanda; R. Bassini; D. Belver; A. V. Belyaev; A. Blanco; M. Böhmer; J. L. Boyard; P. Braun-Munzinger; P. Cabanelas; E. Castro; S. Chernenko; T. Christ; M. Destefanis; J. Díaz; F. Dohrmann; A. Dybczak; T. Eberl; L. Fabbietti; O. V. Fateev; P. Finocchiaro; P. Fonte; J. Friese; I. Fröhlich; T. Galatyuk; J. A. Garzón; R. Gernhäuser; A. Gil; C. Gilardi; M. Golubeva; D. González-Díaz; F. Guber; T. Hennino; R. Holzmann; I. Iori; A. Ivashkin; M. Jurkovic; B. Kämpfer; K. Kanaki; T. Karavicheva; D. Kirschner; I. Koenig; W. Koenig; B. W. Kolb; R. Kotte; F. Krizek; R. Krücken; W. Kühn; A. Kugler; A. Kurepin; S. Lang; J. S. Lange; K. Lapidus; T. Liu; L. Lopes; M. Lorenz; L. Maier; A. Mangiarotti; J. Markert; V. Metag; B. Michalska; J. Michel; D. Mishra; E. Morinière; J. Mousa; C. Müntz; L. Naumann; J. Otwinowski; Y. C. Pachmayer; M. Palka; Y. Parpottas; V. Pechenov; O. Pechenova; J. Pietraszko; W. Przygoda; B. Ramstein; A. Reshetin; M. Roy-Stephan; A. Rustamov; A. Sadovsky; B. Sailer; P. Salabura; A. Schmah; Yu. G. Sobolev; S. Spataro; B. Spruck; H. Ströbele; J. Stroth; C. Sturm; M. Sudol; A. Tarantola; K. Teilab; P. Tlusty; M. Traxler; R. Trebacz; H. Tsertos; V. Wagner; M. Weber; M. Wisniowski; T. Wojcik; J. Wüstenfeld; S. Yurevich; Y. V. Zanevsky; P. Zhou

    2009-07-21

    We report first results on a deep sub-threshold production of the doubly strange hyperon $\\Xi^-$ in a heavy-ion reaction. At a beam energy of 1.76A GeV the reaction Ar+KCl was studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. A high-statistics and high-purity $\\Lambda$ sample was collected, allowing for the investigation of the decay channel $\\Xi^- \\to \\Lambda \\pi^-$. The deduced $\\Xi^-/(\\Lambda+\\Sigma^0)$ production ratio of $(5.6 \\pm 1.2 ^{+1.8}_{-1.7})\\cdot 10^{-3}$ is significantly larger than available model predictions.

  13. The colouration by Co-60-gamma rays of NaCl and KCl crystals doped with europium ions

    NASA Astrophysics Data System (ADS)

    Davidson, A. T.; Kozakiewicz, A. G.; Derry, T. E.; Comins, J. D.; Suszynska, M.

    Pure and europium doped NaCl and KCl crystals have been irradiated with Co-60 gamma rays and with ultraviolet light. The dose was 10 kGy and temperatures during irradiation were ambient and liquid nitrogen. The effects of irradiation are determined using optical absorption and thermoluminescence. The role of the europium dopant is compared for the two materials. Factors investigated include the temperature of irradiation, the concentration of the dopant and the state of impurity aggregation and precipitation. A link is indicated between impurity precipitates and UV stimulated thermoluminescence.

  14. Study on a regeneration process of LiCl-KCl eutectic based waste salt generated from the pyrochemical process

    SciTech Connect

    Eun, H.C.; Cho, Y.Z.; Choi, J.H.; Kim, J.H.; Lee, T.K.; Park, H.S.; Kim, I.T.; Park, G.I.

    2013-07-01

    A regeneration process of LiCl-KCl eutectic waste salt generated from the pyrochemical process of spent nuclear fuel has been studied. This regeneration process is composed of a chemical conversion process and a vacuum distillation process. Through the regeneration process, a high efficiency of renewable salt recovery can be obtained from the waste salt and rare earth nuclides in the waste salt can be separated as oxide or phosphate forms. Thus, the regeneration process can contribute greatly to a reduction of the waste volume and a creation of durable final waste forms. (authors)

  15. Evaluation of the KCl Denuder Method for Gaseous Oxidized Mercury using HgBr2 at an In-Service AMNet Site

    NASA Astrophysics Data System (ADS)

    McClure, Crystal

    During the summer of 2013, we examined the performance of KCl-coated denuders for measuring gaseous oxidized mercury (GOM) by calibrating with a known source of GOM (i.e., HgBr2) at the North Birmingham SouthEastern Aerosol Research and Characterization (SEARCH) site. We found that KCl-coated denuders have near 95% collection efficiency for HgBr2 in zero air (i.e., air scrubbed of mercury and ozone). However, in ambient air, the efficiency of KCl-coated denuders in capturing HgBr2 dropped to 20-54%. We also found that absolute humidity and ozone each demonstrate a significant inverse correlation with HgBr2 recovery in ambient air. Subsequent laboratory tests with HgBr2 and the KCl-coated denuder show that ozone and absolute humidity cause the release of gaseous elemental Hg from the denuder and thus appear to explain the low recovery in ambient air. Based on these findings, we infer that the KCl denuder method underestimates atmospheric GOM concentrations. A calibration system is needed to accurately measure GOM. The system described in this paper for HgBr2 could be implemented with existing mercury speciation instrumentation and this would improve our knowledge of the response to one potentially important GOM compound.

  16. Phase relations in the system NaCl-KCl-H2O: V. Thermodynamic-PTX analysis of solid-liquid equilibria at high temperatures and pressures

    USGS Publications Warehouse

    Sterner, S.M.; Chou, I.-Ming; Downs, R.T.; Pitzer, Kenneth S.

    1992-01-01

    The Gibbs energies of mixing for NaCl-KCl binary solids and liquids and solid-saturated NaCl-KCl-H2O ternary liquids were modeled using asymmetric Margules treatments. The coefficients of the expressions were calibrated using an extensive array of binary solvus and solidus data, and both binary and ternary liquidus data. Over the PTX range considered, the system exhibits complete liquid miscibility among all three components and extensive solid solution along the anhydrous binary. Solid-liquid and solid-solid phase equilibria were calculated by using the resulting equations and invoking the equality of chemical potentials of NaCl and KCl between appropriate phases at equilibrium. The equations reproduce the ternary liquidus and predict activity coefficients for NaCl and KCl components in the aqueous liquid under solid-saturation conditions between 673 and 1200 K from vapor saturation up to 5 kbar. In the NaCl-KCl anhydrous binary system, the equations describe phase equilibria and predict activity coefficients of the salt components for all stable compositions of solid and liquid phases between room temperature and 1200 K and from 1 bar to 5 kbar. ?? 1992.

  17. Distillation and condensation of LiCl-KCl eutectic salts for a separation of pure salts from salt wastes from an electrorefining process

    NASA Astrophysics Data System (ADS)

    Eun, Hee Chul; Yang, Hee Chul; Lee, Han Soo; Kim, In Tae

    2009-12-01

    Salt separation and recovery from the salt wastes generated from a pyrochemical process is necessary to minimize the high-level waste volumes and to stabilize a final waste form. In this study, the thermal behavior of the LiCl-KCl eutectic salts containing rare earth oxychlorides or oxides was investigated during a vacuum distillation and condensation process. LiCl was more easily vaporized than the other salts (KCl and LiCl-KCl eutectic salt). Vaporization characteristics of LiCl-KCl eutectic salts were similar to that of KCl. The temperature to obtain the vaporization flux (0.1 g min -1 cm -2) was decreased by much as 150 °C by a reduction of the ambient pressure from 5 Torr to 0.5 Torr. Condensation behavior of the salt vapors was different with the ambient pressure. Almost all of the salt vapors were condensed and were formed into salt lumps during a salt distillation at the ambient pressure of 0.5 Torr and they were collected in the condensed salt storage. However, fine salt particles were formed when the salt distillation was performed at 10 Torr and it is difficult for them to be recovered. Therefore, it is thought that a salt vacuum distillation and condensation should be performed to recover almost all of the vaporized salts at a pressure below 0.5 Torr.

  18. Phase relations in the system NaCl-KCl-H sub 2 O: V. Thermodynamic-PTX analysis of solid-liquid equilibria at high temperatures and pressures

    SciTech Connect

    Sterner, S.M.; Pitzer, K.S. ); Iming Chou ); Downs, R.T. )

    1992-06-01

    The Gibbs energies of mixing for NaCl-KCl binary solids and liquids and solid-saturated NaCl-KCl-H{sub 2}O ternary liquids were modeled using asymmetric Margules treatments. The coefficients of the expressions were calibrated using an extensive array of binary solvus and solidus data, and both binary and ternary liquidus data. Over the PTX range considered, the system exhibits complete liquid miscibility among all three components and extensive solid solution along the anhydrous binary. Solid-liquid and solid-solid phase equilibria were calculated by using the resulting equations and invoking the equality of chemical potentials of NaCl and KCl between appropriate phases at equilibrium. The equations reproduce the ternary liquidus and predict activity coefficients for NaCl and KCl components in the aqueous liquid under solid-saturation conditions between 673 and 1,200 K from vapor saturation up to 5 kbar. In the NaCl-KCl anhydrous binary system, the equations describe phase equilibria and predict activity coefficients of the salt components for all stable compositions of solid and liquid phases between room temperature and 1,200 K and from 1 bar to 5 kbar.

  19. Phase equilibria in the system H{sub 2}O-NaCl-KCl-MgCl{sub 2} relevant to salt cake processing

    SciTech Connect

    Bodnar, R.J.; Vityk, M.O.; Hryn, J.N.; Mavrogenes, J.

    1997-02-01

    One waste product in recycling of Al is salt cake, a mixture of Al, salts, and residue oxides. Several methods have been proposed to recycle salt cake, one involving high-temperature leaching of salts from the salt cake. The salt composition can be approximated as a mixture predominantly of NaCl and KCl salts, with lesser amounts of Mg chloride. In order to better assess the feasibility of recycling salt cake, an experimental study was conducted of phase equilibria in the system H{sub 2}O-NaCl-KCl-MgCl{sub 2} at pressure (P), temperature (T), and composition conditions appropriate for high- temperature salt cake recycling. These experiments were designed to evaluate the effect of small amounts (2-10 wt%) of MgCl{sub 2} on solubilities of halite (NaCl) and sylvite (KCl) in saturated solutions (30-50 wt% NaCl+KCl; NaCl:KCl = 1:1 and 3:1) at elevated P and T.

  20. Phase relations in the system NaCl-KCl-H 2O: V. Thermodynamic- PTX analysis of solid-liquid equilibria at high temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Sterner, S. Michael; Chou, I.-Ming; Downs, Robert T.; Pitzer, Kenneth S.

    1992-06-01

    The Gibbs energies of mixing for NaCl-KCl binary solids and liquids and solid-saturated NaCl-KCl-H 2O ternary liquids were modeled using asymmetric Margules treatments. The coefficients of the expressions were calibrated using an extensive array of binary solvus and solidus data, and both binary and ternary liquidus data. Over the PTX range considered, the system exhibits complete liquid miscibility among all three components and extensive solid solution along the anhydrous binary. Solid-liquid and solid-solid phase equilibria were calculated by using the resulting equations and invoking the equality of chemical potentials of NaCl and KCl between appropriate phases at equilibrium. The equations reproduce the ternary liquidus and predict activity coefficients for NaCl and KCl components in the aqueous liquid under solid-saturation conditions between 673 and 1200 K from vapor saturation up to 5 kbar. In the NaCl-KCl anhydrous binary system, the equations describe phase equilibria and predict activity coefficients of the salt components for all stable compositions of solid and liquid phases between room temperature and 1200 K and from 1 bar to 5 kbar.

  1. 131I-MIBG targeting of neuroblastoma cells is acutely enhanced by KCl stimulation through the calcium/calmodulin-dependent kinase pathway.

    PubMed

    Chung, Hyun Woo; Park, Jin Won; Lee, Eun Jeong; Jung, Kyung-Ho; Paik, Jin-Young; Lee, Kyung-Han

    2013-01-01

    The efficacy of (131)I-metaiodobenzylguanidine (MIBG) therapy relies on norepinephrine transporter (NET) function. The ionic make-up of the extracellular fluid critically controls neuronal cell activity and can also affect substrate transport. In this study, we explored the effect of treatment with elevated KCl concentration on MIBG uptake in SK-N-SH neuroblastoma cells. KCl stimulation caused a rapid increase of (131)I-MIBG uptake in a manner that was calcium-dependent and accompanied by activation of calcium/calmodulin-dependent protein kinase (CaMK)II. The effect was completely abolished by KN93, an inhibitor of CaMKI, II, and IV. STO609, a selective inhibitor of CaMK kinase required for activation of CaMKI and IV, but not CaMKII, only modestly attenuated the response. The KCl effect was also completely abrogated by ML7, a selective inhibitor of myosin light chain kinase (MLCK). This restricted form of CaMK activates myosin, which is required for vesicle trafficking. Saturation kinetic analysis revealed KCl stimulation to increase maximal transport velocity without affecting substrate affinity. In conclusion, KCl stimulation rapidly upregulates NET function through the CaMK pathway via activation of CaMKII and MLCK. These findings allow a better understanding of how NET function is acutely modulated by the ionic environment, which in turn may ultimately help improve the efficacy of (131)I-MIBG therapy. PMID:23763646

  2. The multidrug resistance pumps are inhibited by silibinin and apoptosis induced in K562 and KCL22 leukemia cell lines.

    PubMed

    Noori-Daloii, Mohammad Reza; Saffari, Mojtaba; Raoofian, Reza; Yekaninejad, Mirsaeed; Dinehkabodi, Orkideh Saydi; Noori-Daloii, Ali Reza

    2014-05-01

    Silibinin have been introduced for several years as a potent antioxidant in the field of nutraceuticals. Based on wide persuasive effects of this drug, we have decided to investigate the effects of silibinin on chronic myelogenous leukemia (CML) in vitro models, K562 and KCL22 cell lines. Lactate dehydrogenase (LDH) release, microculture tetrazolium test (MTT assay) and real-time PCR were employed to evaluate the effects of silibinin on cell cytotoxicity, cell proliferation and expression of various multidrug resistance genes in these cell lines, respectively. Our results have shown that presence of silibinin has inhibitory effects on cell proliferation of K562 and KCL22 cell lines. Also, our data indicated that silibinin, in a dose-dependent manner with applying no cytotoxic effects, inhibited cell proliferation and reduced mRNA expression levels of some transporter genes e.g. MDR1, MRP3, MRP2, MRP1, MRP5, MRP4, ABCG2, ABCB11, MRP6 and MRP7. The multifarious in vitro inhibitory effects of silibinin are in agreement with growing body of evidence that silibinin would be an efficient anticancer agent in order to be used in multi-target therapy to prevail the therapeutic hold backs against CML. PMID:24522246

  3. Iridoid and aromatic glycosides from Scrophularia ningpoensis Hemsl. and their inhibition of [Ca2+](i) increase induced by KCl.

    PubMed

    Chen, Bin; Liu, Yan; Liu, Hong-Wei; Wang, Nai-Li; Yang, Bao-Feng; Yao, Xin-Sheng

    2008-09-01

    Bioassay-guided fractionation of EtOH extract of the roots of Scrophularia ningpoensis Hemsl. resulted in the isolation of three new iridoid glycosides, i.e., 6''-O-caffeoylharpagide (1), 6''-O-feruloylharpagide (2), and 6''-O-beta-glucopyranosylharpagoside (3), and five new aromatic glycosides, i.e., 2-(3-hydroxy-4-methoxyphenyl)ethyl O-alpha-arabinopyranosyl-(1-->6)-O-alpha-rhamnopyranosyl-(1-->3)-O-beta-glucopyranoside (4), phenyl O-beta-xylopyranosyl-(1-->6)-O-beta-glucopyranoside (5), 3-methylphenyl O-beta-xylopyranosyl-(1-->6)-O-beta-glucopyranoside (6), 6-O-cinnamoyl beta-fructofuranosyl-(2-->1)-O-alpha-glucopyranosyl-(6-->1)-O-alpha-glucopyranoside (7), and 6-O-feruloyl beta-fructofuranosyl-(2-->1)-O-alpha-glucopyranosyl-(6-->1)-O-alpha-glucopyranoside (8), together with four known compounds, i.e., 6''-O-alpha-D-galactopyranosyl harpagoside (9), 6''-O-(p-coumaroyl) harpagide (10), harpagoside (11), and angoroside C (12). Activity of the isolated compounds on [Ca2+](i) increase induced by KCl was evaluated on rat cardiac myocytes using confocal laser scanning microscopy. Iridoid glycosides 1, 10, and 11, and aromatic glycosides 5 and 6 significantly inhibited the increase of [Ca2+](i) induced by KCl at 100 microM. PMID:18816525

  4. Volatile products from the interaction of KCl/g/ with Cr2O3 and LaCrO3 in oxidizing environments. [gas turbine engines

    NASA Technical Reports Server (NTRS)

    Kohl, F. J.; Miller, R. A.; Stearns, C. A.; Fryburg, G. C.; Dillard, J. G.

    1977-01-01

    Based on cooled target collection methods and high pressure mass spectrometer sampling, oxidative vaporization rates and emanating volatile products were evaluated for interactions of KCl(g) with Cr2O3 and LaCrO3 in oxidizing environments. It was found that: (1) increased rates of oxidative vaporization upon exposure to the reactants are exhibited by chromia and fresh lanthanum chromite samples, and (2) these increased rates result from the heterogeneous formation of complex molecules such as KCl sub 1,2,3CrO3 and KOH sub 1,2CrO3. No increased rates were observed for lanthanum chromite subjected to prolonged oxidative vaporization.

  5. Extensive Gustatory Cortex Lesions Significantly Impair Taste Sensitivity to KCl and Quinine but Not to Sucrose in Rats

    PubMed Central

    Bales, Michelle B.; Schier, Lindsey A.; Blonde, Ginger D.; Spector, Alan C.

    2015-01-01

    Recently, we reported that large bilateral gustatory cortex (GC) lesions significantly impair taste sensitivity to salts in rats. Here we extended the tastants examined to include sucrose and quinine in rats with ibotenic acid-induced lesions in GC (GCX) and in sham-operated controls (SHAM). Presurgically, immediately after drinking NaCl, rats received a LiCl or saline injection (i.p.), but postsurgical tests indicated a weak conditioned taste aversion (CTA) even in controls. The rats were then trained and tested in gustometers to discriminate a tastant from water in a two-response operant taste detection task. Psychometric functions were derived for sucrose, KCl, and quinine. Our mapping system was used to determine placement, size, and symmetry of the lesions (~91% GC damage on average). For KCl, there was a significant rightward shift (?EC50 = 0.57 log10 units; p<0.001) in the GCX psychometric function relative to SHAM, replicating our prior work. There was also a significant lesion-induced impairment (?EC50 = 0.41 log10 units; p = 0.006) in quinine sensitivity. Surprisingly, taste sensitivity to sucrose was unaffected by the extensive lesions and was comparable between GCX and SHAM rats. The fact that such large bilateral GC lesions did not shift sucrose psychometric functions relative to SHAM, but did significantly compromise quinine and KCl sensitivity suggests that the neural circuits responsible for the detection of specific taste stimuli are partially dissociable. Lesion-induced impairments were observed in expression of a postsurgical CTA to a maltodextrin solution as assessed in a taste-oriented brief-access test, but were not reflected in a longer term 46-h two-bottle test. Thus, deficits observed in rats after extensive damage to the GC are also dependent on the test used to assess taste function. In conclusion, the degree to which the GC is necessary for the maintenance of normal taste detectability apparently depends on the chemical and/or perceptual features of the stimulus. PMID:26599914

  6. Electrochemical Study of Ni20Cr Coatings Applied by HVOF Process in ZnCl2-KCl at High Temperatures

    PubMed Central

    Porcayo-Calderón, J.; Sotelo-Mazón, O.; Casales-Diaz, M.; Ascencio-Gutierrez, J. A.; Salinas-Bravo, V. M.; Martinez-Gomez, L.

    2014-01-01

    Corrosion behavior of Ni20Cr coatings deposited by HVOF (high velocity oxygen-fuel) process was evaluated in ZnCl2-KCl (1?:?1 mole ratio) molten salts. Electrochemical techniques employed were potentiodynamic polarization curves, open circuit potential, and linear polarization resistance (LPR) measurements. Experimental conditions included static air and temperatures of 350, 400, and 450°C. 304-type SS was evaluated in the same conditions as the Ni20Cr coatings and it was used as a reference material to assess the coatings corrosion resistance. Coatings were evaluated as-deposited and with a grinded surface finished condition. Results showed that Ni20Cr coatings have a better corrosion performance than 304-type SS. Analysis showed that Ni content of the coatings improved its corrosion resistance, and the low corrosion resistance of 304 stainless steel was attributed to the low stability of Fe and Cr and their oxides in the corrosive media used. PMID:25210645

  7. Elasticity, internal excitation, fragmentation, and charge transfer during grazing scattering of fast fullerenes from a KCl(001) surface

    NASA Astrophysics Data System (ADS)

    Wethekam, S.; Merck, J.; Busch, M.; Winter, H.

    2011-02-01

    C60+ and C70+ fullerenes with keV energies are scattered under grazing polar angles of incidence from an atomically clean and flat KCl(001) surface. For this model system of molecule surface interactions, the elastic properties of the fullerenes in front of the surface are studied by polar angular distributions. From the analysis of fragment spectra, the internal excitations of scattered molecules are deduced and excitation mechanisms are identified. Charge fractions indicate a kinematically induced neutralization of the fullerenes. Via an analysis of negatively charged fragments, the transition from a “soft” scattering event with intact outgoing fullerenes to postcollision multifragmentation is analyzed. The data are compared to three-dimensional molecular dynamics simulations based on empirical bond-order potentials.

  8. Deep Subthreshold XI{sup -} Production in Ar+KCl Reactions at 1.76A GeV

    SciTech Connect

    Agakishiev, G.; Destefanis, M.; Gilardi, C.; Kirschner, D.; Kuehn, W.; Lange, J. S.; Metag, V.; Mishra, D.; Pechenova, O.; Spataro, S.; Spruck, B.; Balanda, A.; Dybczak, A.; Michalska, B.; Otwinowski, J.; Przygoda, W.; Salabura, P.; Trebacz, R.; Wisniowski, M.; Wojcik, T.

    2009-09-25

    We report first results on a deep subthreshold production of the doubly strange hyperon XI{sup -} in a heavy-ion reaction. At a beam energy of 1.76A GeV the reaction Ar+KCl was studied with the High Acceptance Di-Electron Spectrometer at SIS18/GSI. A high-statistics and high-purity LAMBDA sample was collected, allowing for the investigation of the decay channel XI{sup -}->LAMBDApi{sup -}. The deduced XI{sup -}/(LAMBDA+SIGMA{sup 0}) production ratio of (5.6+-1.2{sub -1.7}{sup +1.8})x10{sup -3} is significantly larger than available model predictions.

  9. Magnetic anisotropy induced by crystal distortion in Ge1-xMnxTe/PbTe//KCl (001) ferromagnetic semiconductor layers

    NASA Astrophysics Data System (ADS)

    Knoff, W.; ?usakowski, A.; Domaga?a, J. Z.; Minikayev, R.; Taliashvili, B.; ?usakowska, E.; PieniÄ ?ek, A.; Szczerbakow, A.; Story, T.

    2015-09-01

    Ferromagnetic resonance (FMR) study of magnetic anisotropy is presented for thin layers of IV-VI diluted magnetic semiconductor Ge1-xMnxTe with x = 0.14 grown by molecular beam epitaxy on KCl (001) substrate with a thin PbTe buffer. Analysis of the angular dependence of the FMR resonant field reveals that an easy magnetization axis is located near to the normal to the layer plane and is controlled by two crystal distortions present in these rhombohedral Ge1-xMnxTe layers: the ferroelectric distortion with the relative shift of cation and anion sub-lattices along the [111] crystal direction and the biaxial in-plane, compressive strain due to thermal mismatch.

  10. Zr electrorefining process for the treatment of cladding hull waste in LiCl-KCl molten salts

    SciTech Connect

    Lee, Chang Hwa; Lee, You Lee; Jeon, Min Ku; Kang, Kweon Ho; Choi, Yong Taek; Park, Geun Il

    2013-07-01

    Zr electrorefining for the treatment of Zircaloy-4 cladding hull waste is demonstrated in LiCl-KCl-ZrCl{sub 4} molten salts. Although a Zr oxide layer thicker than 5 ?m strongly inhibits the Zr dissolution process, pre-treatment processes increases the dissolution kinetics. For 10 g-scale experiments, the purities of the recovered Zr were 99.54 wt.% and 99.74 wt.% for fresh and oxidized cladding tubes, respectively, with no electrical contact issue. The optimal condition for Zr electrorefining has been found to improve the morphological feature of the recovered Zr, which reduces the salt incorporation by examining the effect of the process parameters such as the ZrCl{sub 4} concentration and the applied potential.

  11. Energy loss of slow C{sub 60}{sup +} ions during grazing scattering from a KCl(001) surface

    SciTech Connect

    Matsushita, T.; Nakajima, K.; Suzuki, M.; Kimura, K.

    2007-09-15

    The energy spectra of 1-3 keV C{sub 60}{sup +} ions reflected from a KCl(001) surface under grazing incidence are measured with an electrostatic spectrometer. Although both nuclear and electronic energy losses are expected to be almost completely suppressed in the grazing scattering of such extremely low energy ions (v{approx}0.01 a.u.) from the wide-band-gap insulator surface, we observe anomalously large energy losses ranging from {approx}25 eV ({theta}{sub i}=1 deg.) to {approx}100 eV ({theta}{sub i}=6 deg.). Fragmentation of C{sub 60}{sup +} ions via sequential C{sub 2} loss is also observed during grazing scattering. We find a strong correlation between the energy loss and the fragmentation. From these results the observed anomalous energy losses are attributed to the internal excitations of C{sub 60}{sup +} ions.

  12. Radiation damage in KBr:Eu sup 2+ and KCl:Eu sup 2+ due to 350 nm laser irradiation

    SciTech Connect

    Merkle, L.D. ); Bandyopadhyay, P.K. )

    1989-10-20

    In the course of a study of excited state absorption in alkali halides doped with Eu{sup 2+} we have observed changes in the absorption spectra similar to those induced by ionizing radiation. Comparison of these data and observed changes in the Eu{sup 2+} fluorescence spectra in KBr and KCl with studies of thermally induced aggregation of Eu{sup 2+}-alkali vacancy dipoles indicate that laser enhancement of such aggregation is primarily responsible for these spectral changes. In KBr:Eu irradiation also produces F-center absorption. The initial rate of F-center production varies as the cube of the laser intensity, suggesting that the irradiation effects are due to three photon generation of electron-hole pairs. This also indicates that near ultraviolet excited state absorption by Eu{sup 2+} observed in these hosts is not due to ionization of the europium.

  13. Resonant Raman scattering in potassium and chlorine {ital K}{sub {beta}} x-ray emission from KCl

    SciTech Connect

    Miyano, K.E.; Ma, Y.; Southworth, S.H.; Cowan, P.L.; Karlin, B.A.

    1996-11-01

    We have measured the potassium {ital K}{sub {beta}} and chlorine {ital K}{sub {beta}} resonant Raman x-ray scattering from KCl. Strong {ital K}-shell absorption peaks are directly reflected in the resonant Raman spectra. The emission spectra are qualitatively evaluated in terms of the associated absorption spectra, based on a simple single-electron model of the scattering process. This model affords direct interpretation of the energy, line shape, and intensity variations of the emission spectra. In the resonant Raman regime, energy offsets between the data and the model predictions are attributed to binding energy differences between intermediate and final state excitons; thus these offsets indicate that the associated peaks in the absorption spectra are excitonic in nature. {copyright} {ital 1996 The American Physical Society.}

  14. pp and ?? intensity interferometry in collisions of Ar+KCl at 1.76A GeV

    NASA Astrophysics Data System (ADS)

    Agakishiev, G.; Balanda, A.; Bannier, B.; Bassini, R.; Belver, D.; Belyaev, A. V.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; D?az, J.; Dohrmann, F.; Dybczak, A.; Eberl, T.; Epple, E.; Fabbietti, L.; Fateev, O. V.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gil, A.; Gilardi, C.; Golubeva, M.; González-D?az, D.; Guber, F.; Gumberidze, M.; Heilmann, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Huck, P.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Krizek, F.; Krücken, R.; Kühn, W.; Kugler, A.; Kurepin, A.; Lang, S.; Lange, J. S.; Lapidus, K.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Morinière, E.; Mousa, J.; Müntz, C.; Naumann, L.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pérez Cavalcanti, T.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy-Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wendisch, C.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y. V.; Zhou, P.; Zumbruch, P.

    2011-05-01

    Results on pp, ?+?+, and ?-?- intensity interferometry are reported for collisions of Ar+KCl at 1.76 A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The experimental correlation functions as a function of the relative momentum are compared to model calculations allowing the determination of the space-time extent of the corresponding emission sources. The ?? source radii are found significantly larger than the pp emission radius. The present radii do well complement the beam-energy dependences of Gaussian source radii of the collision system of size A + A ? 40 + 40 . The pp source radius at fixed beam energy is found to increase linearly with the cube root of the number of participants. From this trend, a lower limit of the pp correlation radius is deduced.

  15. LEED and PIRS structure analysis of physisorbed molecules on insulators: Monolayer C2D2/KCl(100)

    NASA Astrophysics Data System (ADS)

    Vogt, Jochen; Weiss, Helmut

    2008-03-01

    The structure of the monolayer C2D2 adsorbed on a KCl(100) single crystal surface has been investigated by means of polarization infrared spectroscopy (PIRS) in transmission geometry at oblique incidence and low-energy electron diffraction (LEED). Infrared spectra in the region of the ?3 asymmetric stretch vibration show at 75K a singlet absorption at 2395.6cm-1 . From the ratio of the integrated absorptions in s - and p -polarized spectra, a parallel orientation of the molecules with respect to the surface is deduced. The observed LEED diffraction patterns are consistent with a (2×2)R45° lattice with two glide planes, in agreement with the parallel orientation of the molecules. LEED beam intensities of five inequivalent beams were recorded as a function of electron energy and the resulting I(V) curves were analyzed using the tensor LEED approach. According to the I(V) analysis and the analysis of the PIRS spectra, an adsorption geometry with two energetically equivalent but translationally inequivalent molecules in the surface unit cell is deduced with adsorption sites 3.14Å above the K+ cations. While IR spectroscopy supports a herringbone structure with the molecular axis of nearest neighbors intersecting at 90°, the LEED analysis is consistent with an intersection of 62°. These deviating results for the azimuthal orientations of the molecules on the KCl(100) surface are discussed within the concept of “split positions” [Over , Phys. Rev. B 52, 16812 (1995)] and the consideration of the in-plane libron dynamics of adsorbed molecules.

  16. Effect of partial NaCl substitution with KCl on the texture profile, microstructure, and sensory properties of low-moisture mozzarella cheese.

    PubMed

    Ayyash, Mutamed M; Sherkat, Frank; Shah, Nagendra P

    2013-02-01

    The effect of partial substitution of NaCl with KCl on texture profile, soluble Ca, K, Na, and P, and microstructure of low-moisture mozzarella cheese (LMMC) was investigated. LMMC batches were prepared using four combinations of NaCl and KCl salt viz., NaCl only, NaCl:KCl, 3:1, 1:1 and 1:3 (w/w); all used at of 46 g/kg curd and plasticised in 4% brine containing the above salt mixtures. Texture profile, microstructure, and percentages of soluble Ca, K, Na, and P were determined. There were no significant differences in hardness, cohesiveness, adhesiveness, and gumminess among the experimental LMMC batches. Environmental scanning electron microscopy images showed compact and homogeneous structure of LMMC at day 27 of storage; however, no significant difference was observed among the experimental LMMC batches. Hardness increased significantly in all experimental LMMC during storage. LMMC salted with NaCl/KCl mixtures had almost similar sensory properties compared with the control. There was no significant difference in creaminess, bitterness, saltiness, sour-acid, and vinegary taste among the experimental LMMC at the same storage period. PMID:22998741

  17. Programme Structure and Graduation Requirements for NUS B.Sc. (Hons.) in Chemistry KCL M.Sc. in Forensic Science Concurrent Degree Programme

    E-print Network

    Yao, Shao Q

    .Sc. in Forensic Science Concurrent Degree Programme Concurrent Degree Requirements NUS MCs required Cumulative NUS ECTS Cumulative NUS MCs 7BBFM125 Principles of Forensic Science 15 10 # 7BBFM126 The Forensic Process Project 30 20 Sub­total for M.Sc. Portion 40 Total MCs for NUS-KCL CDP in Forensic Science 200 # Credits

  18. The importance of SO{sub 2} and SO{sub 3} for sulphation of gaseous KCl - An experimental investigation in a biomass fired CFB boiler

    SciTech Connect

    Kassman, Haakan; Baefver, Linda; Aamand, Lars-Erik

    2010-09-15

    This paper is based on results obtained during co-combustion of wood pellets and straw in a 12 MW circulating fluidised bed (CFB) boiler. Elemental sulphur (S) and ammonium sulphate ((NH{sub 4}){sub 2}SO{sub 4}) were used as additives to convert the alkali chlorides (mainly KCl) to less corrosive alkali sulphates. Their performance was then evaluated using several measurement tools including, IACM (on-line measurements of gaseous alkali chlorides), a low-pressure impactor (particle size distribution and chemical composition of extracted fly ash particles), and deposit probes (chemical composition in deposits collected). The importance of the presence of either SO{sub 2} or SO{sub 3} for gas phase sulphation of KCl is also discussed. Ammonium sulphate performed significantly better than elemental sulphur. A more efficient sulphation of gaseous KCl was achieved with (NH{sub 4}){sub 2}SO{sub 4} even when the S/Cl molar ratio was less than half compared to sulphur. Thus the presence of gaseous SO{sub 3} is of greater importance than that of SO{sub 2} for the sulphation of gaseous KCl. (author)

  19. Effects of Partial Substitutions of NaCl with KCl, CaSO4 and MgSO4 on the Quality and Sensorial Properties of Pork Patties

    PubMed Central

    Chun, Ji-Yeon; Cho, Hyung-Yong; Min, Sang-Gi

    2014-01-01

    This study investigated the effects of NaCl replacers (KCl, CaSO4, and MgSO4) on the quality and sensorial properties of pork patty. In the characteristics of spray-dried salt particles, KCl showed the largest particle size with low viscosity in solution. Meanwhile CaSO4 treatment resulted in the smallest particle size and the highest viscosity (p<0.05). In comparison of the qualities of pork patties manufactured by varying level of Na replacers, MgSO4 treatment exhibited low cooking loss comparing to control (p<0.05). Textural properties of KCl and MgSO4 treatments showed similar pattern, i.e., low level of the replacers caused harder and less adhesive texture than those of control (p<0.05), whereas the hardness of these products was not different with control when the replacers were added more than 1.0%. The addition of CaSO4 also manifested harder and less adhesive than control (p<0.05), but the textural properties of CaSO4 treatment was not affected by level of Ca-salt. Eventually, sensorial properties indicated that KCl and CaSO4 influenced negative effects on pork patties. In contrast, MgSO4 showed better sensorial properties in juiciness intensity, tenderness intensity as well as overall acceptability than control, reflecting that MgSO4 was an effective Na-replacer in meat product formulation.

  20. Experimental Determination of Calcite Solubility in H2O-KCl-NaCl-LiCl Solutions at 700 °C and 8 kbar

    NASA Astrophysics Data System (ADS)

    Eguchi, J.; Manning, C. E.; Li, Y.

    2013-12-01

    Calcium carbonate minerals are an important reservoir for subducted carbon. Their stability and solubility plays a major role in mediating the loss of carbon from subducting lithosphere, and therefore in the balance between carbon returned to the surface via arc volcanism and carbon delivered to the mantle. Relatively little oxidized carbon is liberated by mineral transformations during H2O infiltration (e.g., Connolly and Kerrick, 2001, Nature, 411, 293); however, CaCO3 dissolution in alkali-halide brines may liberate significant carbon (Newton and Manning, 2002, Am. Min., 87, 1401). We built on the work of Newton and Manning (2002) by measuring the solubility of calcite in NaCl, KCl and LiCl brines at 700°C and 8 kbar. All experiments employed hydrothermal piston-cylinder and weight-loss methods. We first established solubility as a function of salt concentration for binary LiCl-, KCl-, and NaCl-H2O solutions. In all solutions, calcite solubility increases exponentially with increasing salt mole fraction. At a given salt concentration, calcite solubility increases as the dissolved cation becomes progressively lighter; i.e., solubility increases with salt identity as KClKCl, KCl-LiCl, NaCl-LiCl). Solubilities in salt mixtures increased linearly as a function of chemical hardness, with the solubilities of CaCO3 in the mixtures being bounded by the solubilities of the end-member salts. Observations imply that calcite solubility in salt solutions are predictable using Pearson's hard-soft acid-base rules. Our results demonstrate that fluid salinity exerts a strong control on carbon transport in high-pressure metasomatic environments, such as subduction zones.

  1. The role of activator concentration and precipitate formation on optical and dosimetric properties of KCl:Eu{sup 2+} storage phosphor detectors

    SciTech Connect

    Hansel, Rachael A.; Xiao, Zhiyan; Hu, Yanle; Green, Olga; Yang, Deshan; Harold Li, H.

    2013-09-15

    Purpose: The activator ion (Eu{sup 2+} in KCl:Eu{sup 2+}) plays an important role in the photostimulated luminescence (PSL) mechanism of storage phosphor radiation detectors. In order to design an accurate, effective, and robust detector, it is important to understand how the activator ion concentration affects the structure and, consequently, radiation detection properties of KCl:Eu{sup 2+}.Methods: Potassium chloride pellets were fabricated with various amounts of europium dopant (0.01–5.0 mol.% Eu{sup 2+}). Clinical radiation doses were given with a 6 MV linear accelerator. Radiation doses larger than 100 Gy were given with a {sup 137}Cs irradiator. Dose response curves, radiation hardness, and temporal signal stability were measured using a laboratory PSL readout system. The crystal structure of the material was studied using x ray diffraction and luminescence spectroscopy.Results: The most intense PSL signal was from samples with 1.0 mol.% Eu. However, samples with concentrations higher than 0.05 mol.% Eu exhibited significant degradation in PSL intensity for cumulated doses larger than 3000 Gy. Structural and luminescence spectroscopy showed clear evidence of precipitate phases within the KCl lattice, especially for high activator concentrations. Analysis of PL emission spectra showed that interactions between Eu-V{sub c} dipoles and Eu-V{sub c} trimers could explain trends in PSL sensitivity and radiation hardness observations.Conclusions: The concentration of the activator ion (Eu{sup 2+}) significantly affects radiation detection properties of the storage phosphor KCl:Eu{sup 2+}. An activator concentration between 0.01 and 0.05 mol.% Eu in KCl:Eu{sup 2+} storage phosphor detectors is recommended for linear dose response, good PSL sensitivity, predictable temporal stability, and high reusability for megavoltage radiation detection.

  2. Composition of steam in the system NaCl-KCl-H 2O-quartz at 600°C

    NASA Astrophysics Data System (ADS)

    Fournier, Robert O.; Thompson, J. Michael

    1993-09-01

    In the system NaCl-KCl-H 2O, with and without ?-quartz present, steam was equilibrated in a large-volume reaction vessel with brine and/or precipitated salt at 600°C and pressures ranging from about 100 to 0.4 MPa. Episodically, steam was extracted for chemical analysis, accompanied by a decrease in pressure within the reaction vessel. In the absence of precipitated salt, within the analytical uncertainty stoichiometric quantities of Cl and total alkali, metals (Na + K) dissolve in steam coexisting with chloriderich brine. In contrast, in the presence of precipitated salt (in our experiments halite with some KCl in solid solution), significant excess chloride as associated hydrogen chloride (HCl 0°) dissolves in steam. The HCl 0 is generated by the reaction of steam with solid NaCl(s), producing solid NaOH(s) that diffuses into halite, forming a solid solution. In our quasistatic experiments, compared to dynamic flow-through experiments of others, higher initial ratios of H 2O/NaCl have apparently resulted in higher model fractions of NaOH(s) in solid solution in halite. This, in turn, resulted in incrementally higher concentrations of associated NaOH o dissolved in steam. Addition of quartz to the system NaCl + KC1 + H 2O resulted in an order of magnitude increase in the concentration of HCl 0 dissolved in steam, apparently as a consequence of the formation of sodium disilicate by reaction of silica with NaOH(s). The measured dissolved silica in steam saturated with alkali halides at 600°C in the pressure range 7-70 MPa agrees nicely with calculated values of the solubility of ?-quartz obtained using the equation of Fournier and Potter (1982), corrected for dissolved salt by the method of FOURNIER (1983). Na/K ratios in steam at 600°C tend to be slightly greater than in coexisting brine. When precipitated halite is present, larger mole fractions of NaOH(s) in solid solution in that halite apparently result in even larger Na/K ratios in coexisting steam. Precipitation of more halite as a consequence of repeated depressurization episodes results in decreased Na/K ratios in both the brine and coexisting steam phases, indicating that the lower pressures begin to favor K over Na in the vapor. When steam is in contact with precipitated salts in the absence of brine, the Na/K ratio in the steam is less than that of the bulk composition of the salt-H 2O system.

  3. Composition of steam in the system NaCl-KCl-H2O-quartz at 600°C

    USGS Publications Warehouse

    Fournier, Robert O.; Thompson, J. Michael

    1993-01-01

    In the system NaCl-KCl-H2O, with and without ??-quartz present, steam was equilibrated in a large-volume reaction vessel with brine and/or precipitated salt at 600??C and pressures ranging from about 100 to 0.4 MPa. Episodically, steam was extracted for chemical analysis, accompanied by a decrease in pressure within the reaction vessel. In the absence of precipitated salt, within the analytical uncertainty stoichiometric quantities of Cl and total alkali, metals (Na + K) dissolve in steam coexisting with chloriderich brine. In contrast, in the presence of precipitated salt (in our experiments halite with some KCl in solid solution), significant excess chloride as associated hydrogen chloride (HCl0??) dissolves in steam. The HCl0 is generated by the reaction of steam with solid NaCl(s), producing solid NaOH(s) that diffuses into halite, forming a solid solution. In our quasistatic experiments, compared to dynamic flow-through experiments of others, higher initial ratios of H2O/NaCl have apparently resulted in higher model fractions of NaOH(s) in solid solution in halite. This, in turn, resulted in incrementally higher concentrations of associated NaOHo dissolved in steam. Addition of quartz to the system NaCl + KC1 + H2O resulted in an order of magnitude increase in the concentration of HCl0 dissolved in steam, apparently as a consequence of the formation of sodium disilicate by reaction of silica with NaOH(s). The measured dissolved silica in steam saturated with alkali halides at 600??C in the pressure range 7-70 MPa agrees nicely with calculated values of the solubility of ??-quartz obtained using the equation of Fournier and Potter (1982), corrected for dissolved salt by the method of fournier (1983). Na K ratios in steam at 600??C tend to be slightly greater than in coexisting brine. When precipitated halite is present, larger mole fractions of NaOH(s) in solid solution in that halite apparently result in even larger Na K ratios in coexisting steam. Precipitation of more halite as a consequence of repeated depressurization episodes results in decreased Na K ratios in both the brine and coexisting steam phases, indicating that the lower pressures begin to favor K over Na in the vapor. When steam is in contact with precipitated salts in the absence of brine, the Na K ratio in the steam is less than that of the bulk composition of the salt-H2O system. ?? 1993.

  4. Partition of chlorine compounds between silicate melt and hydrothermal solutions: I. Partition of NaCl-KCl

    NASA Astrophysics Data System (ADS)

    Shinohara, Hiroshi; Iiyama, J. Toshimichi; Matsuo, Sadao

    1989-10-01

    The partition experiments of NaCl and KCl between silicate melts and aqueous chloride solutions were carried at a temperature of 810°C in the pressure range from 0.6 to 6.0 kb. The chloride concentration in the melt (CClm) was constant in certain ranges of chloride concentration in the aqueous phase (CClaq) at 0.6 and 1.2 kb, which reveals the presence of vapor-liquid immiscibility of the aqueous solution. The variation diagram of CClm and CClaq can be applied to the study of aqueous phases as a new method. The partition ratio of chloride (DClm/aq = CClm/CClaq) exhibits a strong negative pressure dependence, which is attributed to the large negative partial molar volume of chlorides in the aqueous phase. The distribution coefficient of Na and K (DNa/KM/Aq = (CNam/CKm/CNaaq/CKaq)) is about 0.75 and has little pressure dependence at pressures higher than 2.2 kb. The distribution coefficient, however, has a positive pressure dependence at pressures lower than 1.2 kb.

  5. {Lambda}-p femtoscopy in collisions of Ar+KCl at 1.76A GeV

    SciTech Connect

    Agakishiev, G.; Destefanis, M.; Gilardi, C.; Kirschner, D.; Kuehn, W.; Lange, J. S.; Metag, V.; Mishra, D.; Pechenova, O.; Spataro, S.; Spruck, B.; Balanda, A.; Dybczak, A.; Michalska, B.; Otwinowski, J.; Przygoda, W.; Salabura, P.; Trebacz, R.; Wisniowski, M.; Wojcik, T.

    2010-08-15

    Results on {Lambda}p femtoscopy are reported at the lowest energy so far. At a beam energy of 1.76A GeV, the reaction Ar+KCl was studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. A high-statistics and high-purity {Lambda} sample was collected, allowing for the investigation of {Lambda}p correlations at low relative momenta. The experimental correlation function is compared to corresponding model calculations allowing the determination of the space-time extent of the {Lambda}p emission source. The {Lambda}p source radius is found to be slightly smaller than the pp correlation radius for a similar collision system. The present {Lambda}p radius is significantly smaller than that found for Au+Au/Pb+Pb collisions in the AGS, SPS, and RHIC energy domains but larger than that observed for electroproduction from He. Taking into account all available data, we find the {Lambda}p source radius to increase almost linearly with the number of participants to the power of one-third.

  6. INTERACTION OF LASER RADIATION WITH MATTER: Influence of Ca and Pb impurities on the bulk optical strength of ultrapure NaCl and KCl crystals

    NASA Astrophysics Data System (ADS)

    Vinogradov, An V.; Voszka, R.; Kovalev, Valerii I.; Fa?zullov, F. S.; Janszky, J.

    1987-06-01

    A significant increase (by a factor of about 3) of the bulk damage threshold in the case of interaction of CO2 laser radiation pulses with ultrapure NaCl and KCl crystals grown in a reactive atmosphere was observed on introduction of divalent metal ions Ca and Pb in concentrations of 10-5-10-6 mol/mol. Impurities were introduced in concentrations of 10-8-10-3 and 2×10-7-10-4 mol/mol into the melts of KCl and NaCl, respectively. The concentration of other impurities (including OH) did not exceed ~10-6 mol/mol. A physical model was developed to account for the observed dependence on the basis of an analogy between a system of colloidal particles and F centers in a crystal and a liquid-vapor system.

  7. Volatile products from the interaction of KCl(g) with Cr2O3 and LaCrO3 in oxidizing environments

    NASA Technical Reports Server (NTRS)

    Kohl, F. J.; Miller, R. A.; Stearns, C. A.; Fryburg, G. C.; Dillard, J. G.

    1977-01-01

    Cooled target collection techniques and high pressure mass spectrometric sampling were used to measure the relative rates of oxidative vaporization and to identify the volatile products emanating from samples of chromia and Mg-doped lanthanum chromite. The materials were exposed to partial pressures of KCl with and without H2O in one atmosphere of slowly flowing oxygen at elevated temperatures. Chromia and fresh samples of lanthanum chromite exhibited enhanced rates of oxidative vaporization upon exposure to these reactants. Mass spectrometric identification showed that the enhancements resulted from the heterogeneous formation of complex molecules of the type KCl sub 1,2,3 CrO3 and KOH sub l,2 CrO3. Lanthanum chromite that had undergone prolonged oxidative vaporization exhibited no enhanced oxidation upon exposure to the reactants.

  8. Electrochemical Study on the Electrodeposition of U, Nd, Ce, La and Y on a Liquid Cadmium Cathode in a LiCl-KCl Eutectic Salt

    SciTech Connect

    Sung Bin Park; Jong Hyeon Lee; Sung Chan Hwang; Young Ho Kang; Joon Bo Shim; Han Soo Lee; Eung Ho Kim; Seong Won Park

    2007-07-01

    Electro-depositions of U, Nd, Ce, La and Y on a liquid cadmium cathode in a LiCl-KCl eutectic salt were studied by using an electrolytic cell. For the LiCl-KCl-UCl{sub 3}- NdCl{sub 3}-CeCl{sub 3}-LaCl{sub 3}-YCl{sub 3}/Cd system, cyclic voltammograms and polarization curves were measured and the electrochemical properties of the system were discussed. From the results of the electro-depositions of U and rare earth metals on the LCC, separation factors and recovery ratios of U and REs were obtained and co-electro-depositions of U and REs were investigated. (authors)

  9. Physical chemistry of molten-salt batteries. Final report, 1 October 1980-September 1981. Current-induced composition gradients in molten LiCl-KCl

    SciTech Connect

    Vallet, C.E.; Heatherly, D.E.; Braunstein, J.

    1982-10-01

    Current-induced composition gradients have been predicted in mixed molten salt battery electrolytes. Composition shifts, if large enough, can produce significant deleterious effects, such as solid phase precipitation in or near the electrodes of molten salt batteries, including the LiAl/LiCl-KCl/FeS/sub x/ battery. Quantitative measurements are needed to determine the extent of the gradients and to find means to reduce them. This report presents the first quantitative SEM/EDX measurements with high distance resolution (<50 ..mu..m) of the shape of the composition profile in LiCl-KCl electrolyzed between LiAl electrodes. Also, current-induced precipitation of LiCl in a porous LiAl anode is indicated by SEM/EDX examination. The measured compositions are consistent with predictions from mass transport models based on the electrode reactions, migrational and diffusional mobilities. 5 figures, 4 tables.

  10. Control for oriented growth of large size KCl crystals by the competition between spontaneous and induced nucleation/growth on a Langmuir Blodgett film

    NASA Astrophysics Data System (ADS)

    Lu, Fei; Zhao, Xinmei; Zhou, Guangdong; Wang, Hai-Shui; Ozaki, Yukihiro

    2008-06-01

    Langmuir-Blodgett (LB) film of stearic acid was used as template to induce the nucleation and growth of KCl crystals when the KCl solution was cooled from 50 to 25 °C. When the LB film template was vertically dipped into the solution, only induced crystals with (1 1 0) orientation were formed. However, if the template was horizontally placed into solutions, both the induced nuclei at the solution/film interface and spontaneous nuclei formed in solution were simultaneously absorbed onto the LB film, and then grew further to form crystals. X-ray diffraction (XRD) patterns and optical microscopy images showed that the orientation and morphology of the crystals were controlled properly by changing the orientation and position of the LB films in the solutions.

  11. Measurement of the thermal diffusivity of molten KCl up to 1,000/degree/C by the forced Rayleigh scattering method

    SciTech Connect

    Nagasaka, Y.; Nagashima, A.

    1988-11-01

    This paper describes measurement of the thermal diffusivity of molten KCl in the temperature range from 804 to 1,030/degree/C by the forced Rayleigh scattering method. In this contact-free optical measuring technique for the thermal diffusivity of liquids, a sample needs to be colored by the admixture of a dye for suitable absorption of a heating laser beam. The dye substances employed are CoCl/sub 2/ and NiCl/sub 2/, which were chosen through the experimental evaluation. The accuracy is estimated to be /plus minus/7% for molten KCl colored with NiCl/sub 2/. The results converted to thermal conductivity show one of the smallest values among other previous data; the difference is a factor of four. The present study demonstrates the promising applicability of the forced Rayleigh scattering method to the measurement of high-temperature molten salts, which has never been attained by other conventional methods.

  12. Physical chemistry of molten salt batteries. Final report for period October 1, 1979-September 30, 1980. Current-induced composition gradients in molten LiCl-KCl

    SciTech Connect

    Braunstein, J.; Cantor, S.; Vallet, C.E.

    1981-03-01

    Current induced composition gradients were demonstrated in the molten LiCl-KCl eutectic mixture, the electrolyte of an LiAl/LiCl-KCl/FeS/sub x/ battery. The gradients were produced by electrolysis of the salt between LiAl electrodes at currents of 50 to 100 mA cm/sup -2/, and quenching. Analysis of composition profiles in quenched samples was by atomic absorption spectroscopy, which gave good precision, and by x-ray fluorescence spectroscopy in a scanning electron microscope (SEM/EDX), which gave good distance resolution. Work is in progress to improve the precision of the SEM/EDX measurements to that demonstrated in model systems.

  13. Reduction behavior of UO22+ in molten LiCl-RbCl and LiCl-KCl eutectics by using tungsten

    NASA Astrophysics Data System (ADS)

    Nagai, Takayuki; Uehara, Akihiro; Fujii, Toshiyuki; Yamana, Hajimu

    2013-08-01

    The reduction of uranium from UO22+ to UO2+ or U4+ in molten LiCl-RbCl and LiCl-KCl eutectics was examined by using tungsten and chlorine gas. Spectrophotometric technique was adopted to determine the concentration of uranium species. When tungsten was immersed into the LiCl-RbCl eutectic melt at 400 °C without supplying chlorine gas, 36% of the total weight of the hexavalent of UO22+ was reduced to the pentavalent of UO2+. Under purging chlorine gas into the melt, 96% of UO22+ was reduced to the tetravalent of U4+. Tungsten oxy-chloride of WOCl4 was produced via the reductions of UO22+, which was volatized from the melt and adsorbed on the upper part of experimental cell. On the other hand, 84% of UO22+ in the LiCl-KCl eutectic melt at 500 °C was reduced to U4+ by using tungsten and chlorine gas.

  14. Part 2: Sensitivity comparisons of the mayfly Centroptilum triangulifer to Ceriodaphnia dubia and Daphnia magna using standard reference toxicants; NaCl, KCl and CuSO4.

    PubMed

    Struewing, Katherine A; Lazorchak, James M; Weaver, Paul C; Johnson, Brent R; Funk, David H; Buchwalter, David B

    2015-11-01

    Criteria for establishing water quality standards that are protective for 95% of the native species are generally based upon laboratory toxicity tests. These tests utilize common model organisms that have established test methods. However, for invertebrates these species represent mostly the zooplankton community and are not inclusive of all taxa. In order to examine a potential under-representation in emerging aquatic invertebrates the US Environmental Protection Agency has cultured a parthenogenetic mayfly, Centroptilum triangulifer (Ephemeroptera: Baetidae). This study established a 48h acute and a 14-day short-term chronic testing procedure for C. triangulifer and compared its sensitivity to two model invertebrates, Ceriodaphnia dubia and Daphnia magna. Toxicity tests were conducted to determine mortality and growth effects using standard reference toxicants: NaCl, KCl and CuSO4. In 48-h acute tests, the average LC50 for the mayfly was 659mgL(-1) NaCl, 1957mgL(-1) KCl, and 11?gL(-1) CuSO4. IC25 values, using dry weight as the endpoint, were 228mgL(-1) NaCl, 356mgL(-1) KCl and 5?gL(-1) CuSO4. C. triangulifer was the most sensitive species in NaCl acute and chronic growth tests. At KCl concentrations tested, C. triangulifer was less sensitive for acute tests but was equally or more sensitive than C. dubia and D. magna for growth measurements. This study determined C. triangulifer has great potential and benefits for use in ecotoxicological studies. PMID:24932778

  15. Vapor pressure of ZrCl{sub 4} and HfCl{sub 4} over melt systems KCl + AlCl{sub 3} (1:1.04 mol) + ZrCl{sub 4} and KCl + AlCl{sub 3} (1:1.04 mol) + HfCl{sub 4}

    SciTech Connect

    Tangri, R.P.; Bose, D.K.; Gupta, C.K.

    1995-07-01

    The vapor pressures of ZrCl{sub 4} and HfCl{sub 4} over a molten salt mixture of KCl + AlCl{sub 3} (1:1.04 mol) + XCl{sub 4} (X = Zr, Hf) was determined in the temperature range of 485--627 K by the transpiration technique. The compositions of ZrCl{sub 4} and HfCl{sub 4} in the molten salt system were chosen such that it would be useful for vapor phase separation of ZrCl{sub 4} from Zr(Hf)Cl{sub 4} by an extractive distillation technique employing KCl + AlCl{sub 3} as the fused salt solvent. The relative volatility factor of p{sub HfCl{sub 4}}/p{sub ZrCl{sub 4}} over the KCl + AlCl{sub 3} + XCl{sub 4} (X = Zr, Hf) molten salt systems was determined to be 1.5 in the composition range of 16--30 mol % HfCl{sub 4} or ZrCl{sub 4}. This indicated the possibility of separation of ZrCl{sub 4} and HfCl{sub 4} by extractive distillation with KCl + AlCl{sub 3} molten salt solvent at ambient pressure. Zirconium, with some minor alloy addition, is primarily used in nuclear power reactors as core structural materials due to its low thermal neutron cross section, excellent high-temperature strength, and resistance to corrosion in water.

  16. Vacuum distillation of a mixture of LiCl-KCl eutectic salts and RE oxidative precipitates and a dechlorination and oxidation of RE oxychlorides.

    PubMed

    Eun, Hee Chul; Yang, Hee Chul; Cho, Yung Zun; Lee, Han Soo; Kim, In Tae

    2008-12-30

    In this study, a vacuum distillation of a mixture of LiCl-KCl eutectic salt and rare-earth oxidative precipitates was performed to separate a pure LiCl-KCl eutectic salt from the mixture. Also, a dechlorination and oxidation of the rare-earth oxychlorides was carried out to stabilize a final waste form. The mixture was distilled under a range of 710-759.5Torr of a reduced pressure at a fixed heating rate of 4 degrees C/min and the LiCl-KCl eutectic salt was completely separated from the mixture. The required time for the salt distillation and the starting temperature for the salt vaporization were lowered with a reduction in the pressure. Dechlorination and oxidation of the rare-earth oxychlorides was completed at a temperature below 1300 degrees C and this was dependent on the partial pressure of O2. The rare-earth oxychlorides (NdOCl/PrOCl) were transformed to oxides (Nd2O3/PrO2) during the dechlorination and oxidation process. These results will be utilized to design a concept for a process for recycling the waste salt from an electrorefining process. PMID:18440139

  17. Evaluation of 2.25Cr-1Mo Alloy for Containment of LiCl/KCl Eutectic during the Pyrometallurgical Processing of Used Nuclear Fuel

    SciTech Connect

    B.R. Westphal; S.X. Li; G.L. Fredrickson; D. Vaden; T.A. Johnson; J.C. Wass

    2011-03-01

    Recovery of uranium from the Mk-IV and Mk-V electrorefiner vessels containing a LiCl/KCl eutectic salt has been on-going for 14 and 12 years, respectively, during the pyrometallurgical processing of used nuclear fuel. Although austenitic stainless steels are typically utilized for LiCl/KCl salt systems, the presence of cadmium in the Mk-IV electrorefiner dictates an alternate material. A 2.25Cr-1Mo alloy (ASME SA-387) was chosen due to the absence of nickel in the alloy which has a considerable solubility in cadmium. Using the transition metal impurities (iron, chromium, nickel, molybdenum, and manganese) in the electrorefined uranium products, an algorithm was developed to derive values for the contribution of the transition metals from the various input sources. Weight loss and corrosion rate data for the Mk-V electrorefiner vessel were then generated based on the transition metal impurities in the uranium products. To date, the corrosion rate of the 2.25Cr-1Mo alloy in LiCl/KCl eutectic is outstanding assuming uniform (i.e. non-localized) conditions.

  18. Theoretical study of the long-wavelength optical properties of NaCl, KCl, KBr, and KI

    SciTech Connect

    Hardy, J.R.; Karo, A.M.

    1982-09-15

    We have made a detailed theoretical study of the long-wavelength absorption of NaCl, KCl, KBr, and KI, associated with two-phonon difference processes caused by third-order anharmonic terms in the lattice potential energy. It was found that a simple nearest-neighbor approximation to the anharmonicity, combined with lattice-dynamical eigenfrequencies and eigenvectors generated with the use of a deformation dipole model, can generally account for most of the observed absorption. This agreement was obtained without the use of any disposable parameters, as the form of the first-neighbor potential was predetermined. It was also found that discrepancies between theory and experiment can generally be explained by invoking three-phonon processes and, when these contributions are subtracted from the experimental data, the resultant agreement between theory and experiment is excellent. The effects of lifetime broadening of the final-state phonons were also considered. At the longer wavelengths these may be responsible for part of the discrepancy between theory and experiment. Specifically, for NaCl at 3.09 mm, clear evidence was found of an anomalous contribution to the measured absorption which could have such an origin. However, for KI, which has a ''window'' in its two-phonon absorption at long wavelengths, it is clear that the three-phonon absorption is dominant at low frequencies. Our findings enable us to present certain criteria as to the requirements necessary for a material to possess high transparency in the millimeter-wavelength region. In addition to obtaining theoretical results for the long-wavelength absorption of the four crystals studied, we have also calculated the damping function over the whole two-phonon range and we thus present results for both summation and difference processes.

  19. Comparison of Reactive Mercury Concentrations Measured Simultaneously Using KCl-coated Denuders, Nylon Membranes, and Cation Exchange Membranes

    NASA Astrophysics Data System (ADS)

    Gustin, M. S.; Huang, J.; Miller, M. B.; Weiss-Penzias, P. S.

    2012-12-01

    There is much debate about the chemistry of reactive gaseous and particle bound mercury (Hg) in the atmosphere, and the processes associated with formation. In addition, there are concerns regarding the interferences and calibration of the widely used Tekran® 2537/1130/1135 Hg measurement system. To investigate these we developed simple laboratory and field sampling systems designed to collect and analyze reactive Hg (Hg (II), Hg (I) and/or particle bound). A manifold system was applied in the laboratory, and in the field, in-series and -parallel membranes, flow controllers and pumps were utilized. Both systems actively collected reactive Hg using nylon membranes and cation exchange membranes alongside measurements made using the Tekran® system. The analytical system consisted of step wise 2.5 minute thermo-desorption and Hg quantification by cold vapor atomic fluorescence. In the laboratory, we compared the efficiency of these surfaces for collection of HgO, HgCl2, and HgBr2 when permeated into Hg and oxidant free air, and ambient filtered air. Other tests are ongoing. Thus far, results show concentrations measured by the cation exchange membrane were two-to-three fold greater than that measured by the nylon membranes, and three-to -four fold greater than that measured by the KCl-coated annual denuder. Thermo-desorption profiles obtained using nylon membranes show slightly different patterns associated with the reactive Hg compounds as permeated and tested. Field measurements were made at two locations in Reno, Nevada (a high traffic site and an agricultural area) and at Elkhorn Slough, California (marine site). Desorption profiles from nylon membrane differed by site and by time of year. Although the influence of aerosol on this measurement has not been explored, field results suggest different forms of reactive Hg were present in the atmosphere as a function of season and location.

  20. Electrochemical studies and analysis of 1-10 wt% UCl3 concentrations in molten LiCl-KCl eutectic

    NASA Astrophysics Data System (ADS)

    Hoover, Robert O.; Shaltry, Michael R.; Martin, Sean; Sridharan, Kumar; Phongikaroon, Supathorn

    2014-09-01

    Three electrochemical methods - cyclic voltammetry (CV), chronopotentiometry (CP), and anodic stripping voltammetry (ASV) - were applied to solutions of up to 10 wt% UCl3 in the molten LiCl-KCl eutectic salt at 500 °C to determine electrochemical properties and behaviors and to help provide a scientific basis for the development of an in situ electrochemical probe for determining the concentration of uranium in a used nuclear fuel electrorefiner. Diffusion coefficients of UCl4 and UCl3 were calculated to be (6.72 ± 0.360) × 10-6 cm2/s and (1.04 ± 0.17) × 10-5 cm2/s, respectively. Apparent standard reduction potentials were determined to be (-0.381 ± 0.013) V and (-1.502 ± 0.076) V vs. 5 mol% Ag/AgCl or (-1.448 ± 0.013) V and (-2.568 ± 0.076) V vs. Cl2/Cl- for the U(IV)/U(III) and U(III)/U redox couples, respectively. In comparing this data with supercooled thermodynamic data to determine activity coefficients, the thermodynamic database used was important with resulting activity coefficients ranging from 2.34 × 10-3 to 1.08 × 10-2 for UCl4 and 4.94 × 10-5 to 4.50 × 10-4 for UCl3. Of anodic stripping voltammetry and cyclic voltammetry anodic or cathodic peaks, the CV cathodic peak height divided by square root of scan rate was shown to be the most reliable method of determining UCl3 concentration in the molten salt.

  1. Author's personal copy Journal of Power Sources 172 (2007) 908912

    E-print Network

    Park, Byungwoo

    2007-01-01

    Tin phosphates with various mesopore ratios were pre- pared by mixing various amounts of SnF2 and H3PO was added to the SnF2/H3PO4 solution. The molar ratio of SnF2/H3PO4 was fixed at 1.35, while CTAB/H3PO4

  2. The WNK-regulated SPAK/OSR1 kinases directly phosphorylate and inhibit the K+–Cl? co-transporters

    PubMed Central

    delos Heros, Paola; Alessi, Dario R.; Gourlay, Robert; Campbell, David G.; Deak, Maria; Macartney, Thomas J.; Kahle, Kristopher T.; Zhang, Jinwei

    2014-01-01

    Precise homoeostasis of the intracellular concentration of Cl? is achieved via the co-ordinated activities of the Cl? influx and efflux. We demonstrate that the WNK (WNK lysine-deficient protein kinase)-activated SPAK (SPS1-related proline/alanine-rich kinase)/OSR1 (oxidative stress-responsive kinase 1) known to directly phosphorylate and stimulate the N[K]CCs (Na+–K+ ion co-transporters), also promote inhibition of the KCCs (K+–Cl? co-transporters) by directly phosphorylating a recently described C-terminal threonine residue conserved in all KCC isoforms [Site-2 (Thr1048)]. First, we demonstrate that SPAK and OSR1, in the presence of the MO25 regulatory subunit, robustly phosphorylates all KCC isoforms at Site-2 in vitro. Secondly, STOCK1S-50699, a WNK pathway inhibitor, suppresses SPAK/OSR1 activation and KCC3A Site-2 phosphorylation with similar efficiency. Thirdly, in ES (embryonic stem) cells lacking SPAK/OSR1 activity, endogenous phosphorylation of KCC isoforms at Site-2 is abolished and these cells display elevated basal activity of 86Rb+ uptake that was not markedly stimulated further by hypotonic high K+ conditions, consistent with KCC3A activation. Fourthly, a tight correlation exists between SPAK/OSR1 activity and the magnitude of KCC3A Site-2 phosphorylation. Lastly, a Site-2 alanine KCC3A mutant preventing SPAK/OSR1 phosphorylation exhibits increased activity. We also observe that KCCs are directly phosphorylated by SPAK/OSR1, at a novel Site-3 (Thr5 in KCC1/KCC3 and Thr6 in KCC2/KCC4), and a previously recognized KCC3-specific residue, Site-4 (Ser96). These data demonstrate that the WNK-regulated SPAK/OSR1 kinases directly phosphorylate the N[K]CCs and KCCs, promoting their stimulation and inhibition respectively. Given these reciprocal actions with anticipated net effects of increasing Cl? influx, we propose that the targeting of WNK–SPAK/OSR1 with kinase inhibitors might be a novel potent strategy to enhance cellular Cl? extrusion, with potential implications for the therapeutic modulation of epithelial and neuronal ion transport in human disease states. PMID:24393035

  3. Comparison of KCl denuders with the pyrolysis method and calibration using HgBr2 at an in-service AMNET site

    NASA Astrophysics Data System (ADS)

    McClure, C.; Jaffe, D. A.; Edgerton, E.; Jansen, J. J.

    2013-12-01

    During the summer of 2013, we initiated a project to examine the performance of Tekran measurements of Gaseous Oxidized Mercury (GOM) with a pyrolysis method at the North Birmingham SEARCH site. Measurements started in June 2013 and will run until September 2013. This project responds to recent studies that indicate problems with the KCl denuder method for collection of GOM (e.g. Lyman et al., 2010; Gustin et al., 2013; Ambrose et al., 2013). For this project, we compared two GOM measurement systems, one using the KCl denuder method and a second method using high temperature pyrolysis of Hg compounds and detection of the resulting Hg0 vapors. Both instruments were also calibrated using an HgBr2 source to understand the recovery of one possible atmospheric GOM constituent. Both instruments sampled from a common, heated manifold. Past work has shown that in order to fully transmit HgBr2 sample lines must be made from PFA lines and heated to 100 °C. The transmission rate of HgBr2 during this project is approximately 90% over 25 feet of sample tubing at this temperature. Very preliminary results from this study have found that the transmitted HgBr2 is captured with 95% efficiency in carbon-scrubbed ambient air for both the KCl denuder and the pyrolysis method. However, the denuder method appears to be significantly less efficient in the capture of GOM when sampling unaltered ambient air versus the pyrolysis validation of total Hg0. Therefore, calibration of GOM measurements is essential in order to accurately correct for fluctuations in the GOM capture efficiency. We have also found that calibrations for GOM can be done routinely in the field and that these are essential to fully understand the GOM measurements. At present our calibration system is performed manually, but in principle this method could be readily automated.

  4. Phorbol ester attenuates the KCl-induced increase in (Ca/sup 2 +/) and inhibits spontaneous sarcoplasmic reticulum Ca/sup 2 +/ release, in rat cardiac myocytes

    SciTech Connect

    Hansford, R.G.; Capogrossi, M.C.; Kaku, T.; Pelto, D.J.; Filburn, C.H.; Lakatta, E.G.

    1986-03-01

    Partial membrane depolarization induced by increasing the KCl concentration of the medium bathing cardiac myocytes leads to an increase in cell (Ca/sup 2 +/), and accelerates the frequency of spontaneous contractile waves (W) caused by periodic sarcoplasmic reticulum (SR) Ca/sup 2 +/ release. In suspensions of myocytes bathed in 1.0mM Ca/sup 2 +/ at 37 (pH 7.4) and loaded with the fluorescent Ca/sup 2 +/ - indicator Fura-2, by incubation with 2 ..mu..M acetoxymethyl ester for 30 min, the addition of KCl to raise (K/sup +/) from 5 to 30 mM is associated with a rapid (< 10 sec) increase in fluorescence, corresponding to an increased cell (Ca/sup 2 +/). Prior exposure (3 min) to 10/sup -7/ M phorbol myristate acetate (PMA) diminishes this response to 44 +/- 10% of that in control suspensions (n = 9). Under the same conditions W frequency (min/sup -1/) in individual cells in 30 mM KCl averaged 8.3 +/- 0.6. Addition of PMA abolished W within 1 min. Diacylglycerol (10 ..mu..M L..cap alpha..-1,2-dioctanoylglycerol, di C8) had a similar effect on W frequency. The thesis is that PMA attenuates cell Ca/sup 2 +/ overload and its associated potentiation of spontaneous SR Ca/sup 2 +/ oscillations. In view of the efficacy of PMA and di C8, it is suggested that the effect is mediated by protein kinase c, and it may involve an alteration in the intracellular distribution of this enzyme.

  5. Structure of low-temperature IR absorption spectra of KCl and KBr crystals with NO/sub 2/- and NO/sub 3/- anion impurities

    SciTech Connect

    Boiko, V.V.; Kushnirenko, I.Ya.; Shinkarenko, V.K.; Shcherbatskii, V.P.

    1987-11-01

    The vibrational and hyperfine structure of the infrared absorption spectra of KCl and KBr crystals doped with the molecular monovalent anions of nitrogen dioxide and nitrogen trioxide and additionally doped or not doped with divalent cations of calcium and barium is analyzed at a temperature of 4.2 K in this paper. The penetration of the ions into the crystal lattices and their complexing behavior with the halides are determined. The isotopic structure of the infrared spectra is also analyzed for nitrogen dioxide and trioxide anions comprised of nitrogen 14/oxygen 16, nitrogen 15/oxygen 16, nitrogen 14/oxygen 18, and nitrogen 14/oxygen 16/oxygen 18 isotope compositions.

  6. Extensive Lesions in Rat Insular Cortex Significantly Disrupt Taste Sensitivity to NaCl and KCl and Slow Salt Discrimination Learning

    PubMed Central

    Blonde, Ginger D.; Bales, Michelle B.; Spector, Alan C.

    2015-01-01

    While studies of the gustatory cortex (GC) mostly focus on its role in taste aversion learning and memory, the necessity of GC for other fundamental taste-guided behaviors remains largely untested. Here, rats with either excitotoxic lesions targeting GC (n = 26) or sham lesions (n = 14) were assessed for postsurgical retention of a presurgically LiCl-induced conditioned taste aversion (CTA) to 0.1M sucrose using a brief-access taste generalization test in a gustometer. The same animals were then trained in a two-response operant taste detection task and psychophysically tested for their salt (NaCl or KCl) sensitivity. Next, the rats were trained and tested in a NaCl vs. KCl taste discrimination task with concentrations varied. Rats meeting our histological inclusion criterion had large lesions (resulting in a group averaging 80% damage to GC and involving surrounding regions) and showed impaired postsurgical expression of the presurgical CTA (LiCl-injected, n = 9), demonstrated rightward shifts in the NaCl (0.54 log10 shift) and KCl (0.35 log10 shift) psychometric functions, and displayed retarded salt discrimination acquisition (n = 18), but eventually learned and performed the discrimination comparable to sham-operated animals. Interestingly, the degree of deficit between tasks correlated only modestly, if at all, suggesting that idiosyncratic differences in insular cortex lesion topography were the root of the individual differences in the behavioral effects demonstrated here. This latter finding hints at some degree of interanimal variation in the functional topography of insular cortex. Overall, GC appears to be necessary to maintain normal taste sensitivity to NaCl and KCl and for salt discrimination learning. However, higher salt concentrations can be detected and discriminated by rats with extensive damage to GC suggesting that the other resources of the gustatory system are sufficient to maintain partial competence in these tasks, supporting the view that such basic sensory-discriminative taste functions involve distributed processes among central gustatory structures. PMID:25658323

  7. Molten Salt Mixture Properties (KF-ZrF4 and KCl-MgCl2) for Use in RELAP5-3D for High Temperature Reactor Application

    SciTech Connect

    N. A. Anderson; P. Sabharwall

    2012-06-01

    Molten salt coolants are being investigated as primary coolants for a fluoride high-temperature reactor and as secondary coolants for high temperature reactors such as the next generation nuclear plant. This work provides a review of the thermophysical properties of candidate molten salt coolants for use as a secondary heat transfer medium from a high temperature reactor to a processing plant. The molten salts LiF-NaF-KF, KF-ZrF4 and KCl-MgCl2 were considered for use in the secondary coolant loop. The thermophysical properties necessary to add the molten salts KF-ZrF4 and KCl-MgCl2 to RELAP5-3D were gathered for potential modeling purposes. The properties of the molten salt LiF-NaF-KF were already available in RELAP5-3D. The effect that the uncertainty in individual properties had on the Nusselt number was evaluated. This uncertainty in the Nusselt number was shown to be nearly independent of the molten salt temperature.

  8. Separation of CsCl from a Ternary CsCl-LiCl-KCl Salt via a Melt Crystallization Technique for Pyroprocessing Waste Minimization

    SciTech Connect

    Ammon Williams; Supathorn Phongikaroon; Michael Simpson

    2013-02-01

    A parametric study has been conducted to identify the effects of several parameters on the separation of CsCl from molten LiCl-KCl salt via a melt crystallization process. A reverse vertical Bridgman technique was used to grow the salt crystals. The investigated parameters were: (1) the advancement rate, (2) the crucible lid configuration, (3) the amount of salt mixture, (4) the initial composition of CsCl, and (5) the temperature difference between the high and low furnace zones. From each grown crystal, samples were taken axially and analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Results show that CsCl concentrations at the top of the crystals were low and increased to a maximum at the bottom of the salt. Salt (LiCl-KCl) recycle percentages for the experiments ranged from 50% to 75% and the CsCl composition in the waste salt was low. To increase the recycle percentage and the concentration of CsCl in the waste form, the possibility of using multiple crystallization stages was explored to further optimize the process. Results show that multiple crystallization stages are practical and the optimal experimental conditions should be operated at 5.0 mm/hr rate with a lid configuration and temperature difference of 200 °C for a total of five crystallization stages. Under these conditions, up to 88% of the salt can be recycled.

  9. Evaluation of the Electrochemical Behavior of CeCl3 in Molten LiCl-KCl Eutectic Utilizing Metallic Ce as an Anode

    SciTech Connect

    K. C. Marsden; B. Pesic

    2011-04-01

    A study of the electrochemical behavior of CeCl3 in LiCl-KCl eutectic was performed in the temperature range 653-973K to ascertain if CeCl3 is a suitable surrogate for UCl3 in the development of nuclear fuel cycle technologies. Reduction of cerium occurs in a single 3-electron step that is quasi-reversible. The diffusion coefficient of Ce(III) was determined by linear sweep voltammetry and chronopotentiometry. The standard potential of Ce(III)/Ce(0) was measured and used to calculate Gibbs free energy and the activity coefficient. The nucleation of cerium on a tungsten substrate was determined to be instantaneous with hemispherical nuclei whose growth is controlled by linear or hemispherical diffusion. The order of magnitude of the exchange current density was determined by the linear polarization method. The electrochemical characteristics of CeCl3 were compared with those of UCl3 in LiCl-KCl to evaluate the potential of cerium as a surrogate for uranium electrorefining development.

  10. Electrochemical hydrogen absorbing behavior of Pd and Pd-Li alloys in a molten LiCl-KCl-LiH system

    SciTech Connect

    Nohira, T.; Ito, Y.

    1997-07-01

    Electrochemical hydrogen absorption and desorption into/from Pd and Pd-Li alloys were studied in a molten LiCl KCl-LiH system (5 mole percent LiH added) at 673 K. A cyclic voltammogram for a Pd electrode indicates that the current is largely due to a hydrogen-related reaction and partly due to a Li-related reaction. Pd spontaneously changes into PdLiH{sub x} merely by immersion into the molten LiCl-KCl-LiH system, because the anodic hydrogen absorption and the cathodic lithium deposition occur on the same surface. By chronopotentiometry, H/Pd ratios were estimated for Pd, Pd{sub 7}Li, Pd{sub 2}Li, and PdLi electrodes after hydrogen charging at 0.6 V for 0.5 h as 0.05, 0.08, 0.27, and 0.74, respectively. The results show that the hydrogen absorbing ability of the alloys increases as the Li concentration increases. These characteristics can be explained by the stronger interaction of Li-H than of Pd-H. For a D-T neutron generator, the development of new metal-tritide targets is important because the desorption of tritium caused by generated heat prevents high neutron output and long-time operation for conventional Ti-T targets.

  11. An experimental study of the solubility of molybdenum in H[subscript 2]O and KCl?H2O solutions from 500 [degrees]C to 800 [degrees]C, and 150 to 300 MPa

    SciTech Connect

    Ulrich, Thomas; Mavrogenes, John

    2008-04-22

    The solubility of molybdenum (Mo) was determined at temperatures from 500 C to 800 C and 150 to 300 MPa in KCl-H{sub 2}O and pure H{sub 2}O solutions in cold-seal experiments. The solutions were trapped as synthetic fluid inclusions in quartz at experimental conditions, and analyzed by laser ablation inductively coupled plasma mass spectrometry (LA ICPMS). Mo solubilities of 1.6 wt% in the case of KCl-bearing aqueous solutions and up to 0.8 wt% in pure H{sub 2}O were found. Mo solubility is temperature dependent, but not pressure dependent over the investigated range, and correlates positively with salinity (KCl concentration). Molar ratios of {approx}1 for Mo/Cl and Mo/K are derived based on our data. In combination with results of synchrotron X-ray absorption spectroscopy of individual fluid inclusions, it is suggested that Mo-oxo-chloride complexes are present at high salinity (>20 wt% KCl) and ion pairs at moderate to low salinity (<11 wt% KCl) in KCl-H{sub 2}O aqueous solutions. Similarly, in the pure H{sub 2}O experiments molybdic acid is the dominant species in aqueous solution. The results of these hydrothermal Mo experiments fit with earlier studies conducted at lower temperatures and indicate that high Mo concentrations can be transported in aqueous solutions. Therefore, the Mo concentration in aqueous fluids seems not to be the limiting factor for ore formation, whereas precipitation processes and the availability of sulfur appear to be the main controlling factors in the formation of molybdenite (MoS{sub 2}).

  12. An experimental study of the solubility of molybdenum in H 2O and KCl-H 2O solutions from 500 °C to 800 °C, and 150 to 300 MPa

    NASA Astrophysics Data System (ADS)

    Ulrich, Thomas; Mavrogenes, John

    2008-05-01

    The solubility of molybdenum (Mo) was determined at temperatures from 500 °C to 800 °C and 150 to 300 MPa in KCl-H 2O and pure H 2O solutions in cold-seal experiments. The solutions were trapped as synthetic fluid inclusions in quartz at experimental conditions, and analyzed by laser ablation inductively coupled plasma mass spectrometry (LA ICPMS). Mo solubilities of 1.6 wt% in the case of KCl-bearing aqueous solutions and up to 0.8 wt% in pure H 2O were found. Mo solubility is temperature dependent, but not pressure dependent over the investigated range, and correlates positively with salinity (KCl concentration). Molar ratios of ˜1 for Mo/Cl and Mo/K are derived based on our data. In combination with results of synchrotron X-ray absorption spectroscopy of individual fluid inclusions, it is suggested that Mo-oxo-chloride complexes are present at high salinity (>20 wt% KCl) and ion pairs at moderate to low salinity (<11 wt% KCl) in KCl-H 2O aqueous solutions. Similarly, in the pure H 2O experiments molybdic acid is the dominant species in aqueous solution. The results of these hydrothermal Mo experiments fit with earlier studies conducted at lower temperatures and indicate that high Mo concentrations can be transported in aqueous solutions. Therefore, the Mo concentration in aqueous fluids seems not to be the limiting factor for ore formation, whereas precipitation processes and the availability of sulfur appear to be the main controlling factors in the formation of molybdenite (MoS 2).

  13. Vapor-liquid phase equilibria of potassium chloride-water mixtures: Equation-of-state representation for KCl-H sub 2 O and NaCl-H sub 2 O

    SciTech Connect

    Hovey, J.K.; Pitzer, K.S.; Tanger, J.C. IV ); Bischoff, J.L.; Rosenbauer, R.J. )

    1990-02-08

    Measurements of isothermal vapor-liquid compositions for KCl-H{sub 2}O as a function of pressure are reported. An equation of state, which was originally proposed by Pitzer and was improved and used by Tanger and Pitzer to fit the vapor-liquid coexistence surface for NaCl-H{sub 2}O, has been used for representation of the KCl-H{sub 2}O system from 300 to 410{degree}C. Improve parameters are also reported for NaCl-H{sub 2}O from 300 to 500{degree}C.

  14. Vapor-liquid phase equilibria of potassium chloride-water mixtures: Equation-of-state representation for KCl-H2O and NaCl-H2O

    USGS Publications Warehouse

    Hovey, J.K.; Pitzer, Kenneth S.; Tanger, J.C., IV; Bischoff, J.L.; Rosenbauer, R.J.

    1990-01-01

    Measurements of isothermal vapor-liquid compositions for KCl-H2O as a function of pressure are reported. An equation of state, which was originally proposed by Pitzer and was improved and used by Tanger and Pitzer to fit the vapor-liquid coexistence surface for NaCl-H2O, has been used for representation of the KCl-H2O system from 300 to 410??C. Improved parameters are also reported for NaCl-H2O from 300 to 500??C. ?? 1990 American Chemical Society.

  15. Cycle-Life Improvement of Zn/NiOOH Cells by the Addition of Ca(OH)2 to the Zinc Electrode

    E-print Network

    Jain, R.

    2010-01-01

    of rechargeable batteries, thus creating the "electric" car.of individual cars. Another advantage of using batteries isbatteries used in portable consumer products, are much too expensive for use in electric cars.

  16. Mixing-rules of viscosity, electrical conductivity and density of NaCl, KCl and CaCl2 aqueous solutions derived from experiments

    NASA Astrophysics Data System (ADS)

    Milsch, Harald; Kallenberg, Bianca; Holzhauer, Julia; Frick, Stephanie; Blöcher, Guido

    2010-05-01

    Upper-crustal fluids often contain an abundance of dissolved ions significantly affecting their thermo-physical properties. Knowledge of these properties and their relation to both type and concentration of ionic species is of predominant importance for a variety of geotechnical applications, e.g. the provision of energy from deep-seated geothermal reservoirs. We conducted extensive and systematic series of measurements on the viscosity, electrical conductivity and density of synthetic geothermal brines containing varying amounts of dissolved NaCl, KCl and CaCl2 salts. The investigations were performed at ambient pressure and temperatures between 20°C and 80°C, using a Höppler-viscometer, a commercial hand-held four-electrode conductivity meter, and a combination of volumetric and mass measurements for density, respectively. The maximum molalities investigated were 4 mol/kg for KCl and 5 mol/kg for NaCl and CaCl2, respectively. Despite analytical simplicity the results obtained were in good to excellent agreement with tabulated values. The investigations on electrical conductivity showed excellent agreement with Kohlrausch's law of independent migration of ions as well as tabulated values for the respective limiting molar conductivities. Cation-valency strongly affects the dependence of all three thermo-physical properties on salt concentration. At a given temperature, CaCl2 brine shows a decrease in conductivity, a dramatic increase in viscosity, and a departure from linearity for density with concentration above molalities of approximately 3 mol/kg. Moreover, systematic measurements performed with mixtures of the three salts yielded mixing-rules for all three parameters. The predictions of these rules applied to a natural geothermal brine of known chemical composition were in excellent agreement with direct measurements performed with this fluid. After evaluation, such relationships then permit reasonable estimates on thermo-physical properties of fluids having more complex compositions without the need for further measurements. For example, the viscosity of a solution containing an arbitrary composition of NaCl, KCl and CaCl2 can be reasonably predicted by stoichiometrically weighting the individual viscosities measured at the total concentration of the mixture. In our contribution we will critically present the data in comparison to existing data and communicate the mixing-rules derived. Also, we will stress the validity of the conventional conductivity-viscosity relationship based on the balance between electrical and viscous forces. This will constrain the species- and concentration-dependence of both effective ionic radii and ionic mobility and finally might provide insight into the mechanistic origin of the observed valency-dependence of all three thermo-physical parameters.

  17. Electrochemical studies of LaCl{sub 3} and GdCl{sub 3} dissolved in fused LiCl-KCl

    SciTech Connect

    Lantelme, F.; Berghoute, Y.

    1999-11-01

    Molten systems are important as reaction media for the winning of strong oxidation or reducing elements such as fluorine, alkaline, and alkaline earth metals and aluminum. Recently, fused salt electrochemistry has been used for the preparation of refractory metals opening the way to the deposition of metals in solid state. The thermodynamic properties of solutions of lanthanum or gadolinium chlorides in mixed molten LiCl-KCl were determined by electromagnetic force (emf) measurements of LaCl{sub 3} or GdCl{sub 3} formation cells. The temperature dependence of the emf between 380 and 590 C was used to calculate the Gibbs energy and the enthalpy of formation of dissolved LaCl{sub 3} or GdCl{sub 3}. The electrode processes of La(III) and Gd(III) reduced on a tungsten electrode were investigated by cyclic voltammetry and chronopotentiometry.

  18. Mechanism of growth of Bi2+ x Sr2- y CuO6+ ? single crystals in gas cavities in a KCl melt

    NASA Astrophysics Data System (ADS)

    Gorina, Yu. I.; Kalyuzhnaya, G. A.; Rodin, V. V.; Sentyurina, N. N.; Stepanov, V. A.; Chernook, S. G.

    2007-07-01

    High-quality Bi2+ x Sr2- y CuO6+ ? single crystals in a wide range of superconducting properties, from optimally doped to strongly underdoped (including insulators), have been obtained by free growth in gas cavities formed in a KCl flux. A model of crystal growth is proposed, in which the decisive parameter is the chemical transport in a cavity at a low partial oxygen pressure and feeding of the gaseous medium from the charge heated to a higher temperature. In this case, layer-by-layer growth through the vapor-solid mechanism is implemented. This growth, as the most ordered process, makes it possible to obtain faceted plates and whiskers with specular faces, without segregation of other phases.

  19. Separation of actinides from irradiated An-Zr based fuel by electrorefining on solid aluminium cathodes in molten LiCl-KCl

    NASA Astrophysics Data System (ADS)

    Sou?ek, P.; Murakami, T.; Claux, B.; Meier, R.; Malmbeck, R.; Tsukada, T.; Glatz, J.-P.

    2015-04-01

    An electrorefining process for metallic spent nuclear fuel treatment is being investigated in ITU. Solid aluminium cathodes are used for homogeneous recovery of all actinides within the process carried out in molten LiCl-KCl eutectic salt at a temperature of 500 °C. As the selectivity, efficiency and performance of solid Al has been already shown using un-irradiated An-Zr alloy based test fuels, the present work was focused on laboratory-scale demonstration of the process using irradiated METAPHIX-1 fuel composed of U67-Pu19-Zr10-MA2-RE2 (wt.%, MA = Np, Am, Cm, RE = Nd, Ce, Gd, Y). Different electrorefining techniques, conditions and cathode geometries were used during the experiment yielding evaluation of separation factors, kinetic parameters of actinide-aluminium alloy formation, process efficiency and macro-structure characterisation of the deposits. The results confirmed an excellent separation and very high efficiency of the electrorefining process using solid Al cathodes.

  20. Environmentally friendly growth of single-crystalline K{sub 2}Ti{sub 6}O{sub 13} nanoribbons from KCl flux

    SciTech Connect

    Xu Lianqiang; Cheng Li

    2010-02-15

    Single-crystalline K{sub 2}Ti{sub 6}O{sub 13} nanoribbons with typical width ranging from one hundred nanometers to a few hundred nanometers and length up to tens of microns were prepared from KCl flux. The nanoribbons were characterized by a range of methods including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, selected area electron diffraction and high-resolution transmission electron microscopy. Ultraviolet-visible experiments showed that the K{sub 2}Ti{sub 6}O{sub 13} nanoribbons were wide-band semiconductors with a band width E{sub g} = 3.4 eV. The mechanism of one-dimensional growth of the nanoribbons was attributed to the oriented attachment mechanism.

  1. Formation of alloy coatings by no-current diffusion saturation of nickel by ytterbium in an LiCl-KCl-YbCl3 melt

    NASA Astrophysics Data System (ADS)

    El'kin, O. V.; Kovalevskii, A. V.

    2013-05-01

    Gravimetry is used to study the effect of the temperature and time of no-current diffusion ytterbium saturation of nickel in a molten mixture of the LiCl-KCl eutectic with YbCl3 on the specific change in the nickel sample weight w = ? m/ s, where ? m is the change in the sample weight and s is the sample surface area. The dependences of w on the process time are obtained in the temperature range 773-973 K. The experimentally formed alloy Ni-Yb coatings on nickel are examined by chemical analysis, X-ray fluorescence analysis, and X-ray diffraction. The experimental results demonstrate the presence of one structural zone, which consists of a Laves phase, in the diffusion layer.

  2. High-resolution helium time-of-flight studies of Rayleigh surface-phonon dispersion curves of LiF, NaF, and KCl

    NASA Astrophysics Data System (ADS)

    Brusdeylins, G.; Doak, R. Bruce; Toennies, J. Peter

    1983-03-01

    A molecular-beam apparatus is described in which a cold He beam (~=20 meV) of very high velocity resolution (?vv~=0.8%) is scattered from alkali halide single-crystal surfaces. The velocity distribution of the scattered beam is analyzed using time-of-flight (TOF) techniques. The variation of the TOF spectra with target temperature reveals the influence of multiphonon processes, allowing the regime of single-phonon scattering to be experimentally delineated. The inelastic scattering TOF spectra reveal as many as six sharp maxima, most of which can be attributed to creation or annihilation of single Rayleigh-mode surface phonons. Some evidence is also found for interactions with bulk modes at the surface. Phonon frequencies and wave vectors determined from the TOF spectra allow Rayleigh-mode dispersion curves to be measured out to the Brillouin-zone boundary for the (001) face of LiF, NaF, and KCl along the <100> azimuth. The measured dispersion curves agree well with theoretical predictions except for LiF, for which the experimental frequencies are about 10% lower at the zone boundary. For KCl possible evidence is found for a "crossing mode" embedded in the bulk continuum bands. Measurements were also made in the <110> azimuth for LiF; however, the scattering intensities were observed to be so weak that measurements to the zone boundary were not possible. The inelastic scattering is found to be significantly affected by resonant processes involving bound states of the gas-surface potential well. However, Benedek's mechanism of kinematic focusing is shown to have usually only a minor effect upon the distribution of scattered intensity with polar incident angle under the present experimental conditions. TOF spectra for different azimuthal angles indicate that a similar kinematic focusing effect may be expected in azimuthal angular distributions.

  3. Deep sub-threshold K*(892)0 production in collisions of Ar + KCl at 1.76 A GeV

    NASA Astrophysics Data System (ADS)

    Agakishiev, G.; Balanda, A.; Bassini, R.; Belver, D.; Belyaev, A. V.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; Díaz, J.; Dohrmann, F.; Dybczak, A.; Eberl, T.; Epple, E.; Fabbietti, L.; Fateev, O. V.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Gil, A.; Gilardi, C.; Golubeva, M.; González-Díaz, D.; Guber, F.; Gumberidze, M.; Heilmann, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Huck, P.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Krizek, F.; Krücken, R.; Kühn, W.; Kugler, A.; Kurepin, A.; Lang, S.; Lange, J. S.; Lapidus, K.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Morinière, E.; Mousa, J.; Müntz, C.; Naumann, L.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pérez Cavalcanti, T.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy-Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Yu. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wendisch, C.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y. V.; Zumbruch, P.

    2013-03-01

    Results on the deep sub-threshold production of the short-lived hadronic resonance K*(892)0 are reported for collisions of Ar + KCl at 1.76A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The K*(892)0 production probability per central collision of P_{K^{*0}}=(4.4± 1.1 ± 0.5)× 10^{-4} and the K*(892)0/K0 ratio of P_{K^{*0}}/P_{K^0}=(1.9± 0.5± 0.3)× 10^{-2} are determined at the lowest energy so far ( i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, sqrt{s_{NN}}-sqrt{s_{thr}}=-340 MeV). The K*0/K0 ratio is compared with results of other experiments and with the predictions of the UrQMD transport approach and of the statistical hadronization model. The experimental K*0 yield and the K*0/K0 ratio are overestimated by the transport model by factors of about five and two, respectively. In a chemically equilibrated medium the ratio corresponds to a temperature of the thermalized system being systematically lower than the value determined by the yields of the stable and long-lived hadrons produced in Ar + KCl collisions. From the present measurement, we conclude that sub-threshold K* production either cannot be considered to proceed in a system being in thermal equilibrium or these short-lived resonances appear undersaturated, for example as a result of the rescattering of the decay particles in the ambient hadronic medium.

  4. Synthesis of fluorine substituted hydroxyapatite nanopowders and application of the central composite design for determination of its antimicrobial effects

    NASA Astrophysics Data System (ADS)

    Stani?, Vojislav; Dimitrijevi?, Suzana; Antonovi?, Dušan G.; Joki?, Bojan M.; Zec, Slavica P.; Tanaskovi?, Sladjana T.; Rai?evi?, Slavica

    2014-01-01

    Synthetic biomaterials based on fluorine substituted hydroxyapatite are potentially attractive for orthopedic and dental implant applications. The new synthesis of fluorine substituted hydroxyapatite samples were done by neutralization, which consists of adding the solution of HF and H3PO4 in suspension of Ca(OH)2. Characterization studies from XRD, SEM and FTIR spectra showed that crystals are obtained with apatite structure and those particles of all samples are nano size, with an average length of 80 nm and about 15-25 nm in diameter. The central composite design was used in order to determine the optimal conditions for the antimicrobial activity of the synthesized samples. In order to evaluate the influence of operating parameters on the percent of viable cell reduction of Streptococcus mutans, three independent variables were chosen: exposure time, pH of saline and floride concentration in apatite samples. The experimental and predicted antimicrobial activities were in close agreement. Antimicrobial activity of the samples increases with the increase of fluoride concentration and the decreased pH of saline. The maximum antimicrobial activity was achieved at the initial pH of 4.

  5. Synthesis of antimicrobial monophase silver-doped hydroxyapatite nanopowders for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Stani?, Vojislav; Jana?kovi?, Djordje; Dimitrijevi?, Suzana; Tanaskovi?, Sladjana B.; Mitri?, Miodrag; Pavlovi?, Mirjana S.; Krsti?, Aleksandra; Jovanovi?, Dragoljub; Rai?evi?, Slavica

    2011-02-01

    Monophase silver-doped hydroxyapatite (AgxCa10-x(PO4)6(OH)2; 0.002 ? x ? 0.04) nanoparticles were prepared using a neutralization method and investigated with respect to potential medical applications. This method consists of dissolving Ag2O in solution of H3PO4, and the slow addition to suspension of Ca(OH)2 was applied for the purpose of homogenous distribution of silver ions. Characterization studies from XRD, TEM and FTIR spectra showed that obtained crystals are monophase hydroxyapatites and that particles of all samples are of nano size, with average length of 70 nm and about 15-25 nm in diameter. Antimicrobial studies have demonstrated that all silver-doped hydroxyapatite samples exhibit excellent antimicrobial activity in vitro against the following pathogens: Staphylococcus aureus, Escherichia coli and Candida albicans. The hydroxyapatite sample with the highest content of silver has shown the highest antimicrobial activity; killed all cells of E. coli and brought to more than 99% reduction in viable counts of S. aureus and C. albicans. The atomic force microscopic studies illustrate that silver-doped hydroxyapatite sample causes considerable morphological changes of microorganism cells which might be the cause of cells' death. Hemolysis ratios of the silver-doped hydroxyapatite samples were below 3%, indicating good blood compatibility and that are promising as biomaterials.

  6. Revisiting whitlockite, the second most abundant biomineral in bone: nanocrystal synthesis in physiologically relevant conditions and biocompatibility evaluation.

    PubMed

    Jang, Hae Lin; Jin, Kyoungsuk; Lee, Jaehun; Kim, Younghye; Nahm, Seung Hoon; Hong, Kug Sun; Nam, Ki Tae

    2014-01-28

    The synthesis of pure whitlockite (WH: Ca18Mg2(HPO4)2(PO4)12) has remained a challenge even though it is the second most abundant inorganic in living bone. Although a few reports about the precipitation of WH in heterogeneous phases have been published, to date, synthesizing WH without utilizing any effects of a buffer or various other ions remains difficult. Thus, the related research fields have encountered difficulties and have not been fully developed. Here, we developed a large-scale synthesis method for pure WH nanoparticles in a ternary Ca(OH)2-Mg(OH)2-H3PO4 system based on a systematic approach. We used excess Mg(2+) to impede the growth of hydroxyapatite (HAP: Ca10(PO4)6(OH)2) and the formation of other kinetically favored calcium phosphate intermediate phases. In addition, we designed and investigated the synthesis conditions of WH under the acidic pH conditions required to dissolve HAP, which is the most thermodynamically stable phase above pH 4.2, and to incorporate the HPO4(2-) group into the chemical structure of WH. We demonstrated that pure WH nanoparticles can be precipitated under Mg(2+)-rich and acidic pH conditions without any intermediate phases. Interestingly, this synthesized nano-WH showed comparable biocompatibility with HAP. Our methodology for determining the synthesis conditions of WH could provide a new platform for investigating other important precipitants in aqueous systems. PMID:24299655

  7. Synthesis, structural characterisation and antibacterial activity of Ag+-doped fluorapatite nanomaterials prepared by neutralization method

    NASA Astrophysics Data System (ADS)

    Stani?, Vojislav; Radosavljevi?-Mihajlovi?, Ana S.; Živkovi?-Radovanovi?, Vukosava; Nastasijevi?, Branislav; Marinovi?-Cincovi?, Milena; Markovi?, Jelena P.; Budimir, Milica D.

    2015-05-01

    Silver doped fluorapatite nanopowders were synthesised by neutralization method, which consists of dissolving Ag2O in solution of HF and H3PO4 and addition to suspension of Ca(OH)2. The powder XRD, SEM and FTIR studies indicated the formation of a fluorapatite nanomaterials with average length of the particles is about 80 nm and a width of about 15 nm. The FTIR studies show that carbonate content in samples is very small and carbonte ions substitute both phosphate and hydroxyl groups in the crystal structure of samples, forming AB-type fluorapatite. Antibacterial studies have demonstrated that all Ag+-doped fluorapatite samples exhibit bactericidal effect against pathogens: Staphylococcus aureus, Micrococcus luteus and Kllebsiela pneumoniae. Antibacterial activity increased with the increase of Ag+ in the samples. The atomic force microscopy studies revealed extensive damage to the bacterial cell envelops in the presence of Ag+-doped fluorapatite particles which may lead to their death. The synthesized Ag+-doped fluorapatite nanomaterials are promising as antibacterial biomaterials in orthopedics and dentistry.

  8. Evaluation of the physical and antimicrobial properties of silver doped hydroxyapatite depending on the preparation method.

    PubMed

    Dubnika, Arita; Loca, Dagnija; Salma, Ilze; Reinis, Aigars; Poca, Lasma; Berzina-Cimdina, Liga

    2014-02-01

    In the present study, the effect of the preparation method on the physical and antibacterial properties of silver doped hydroxyapatite (HAp/Ag) samples was investigated. HAp/Ag with 0.1-5 % of silver was prepared using two different modified wet chemical precipitation methods. A comparison of thermal stability and thermodynamical properties indicated that the thermal stability and sintering temperature of HAp/Ag were higher than those of pure hydroxyapatite if Ca(NO3)2·4H2O, AgNO3, NH4OH and (NH4)2HPO4 were used as raw materials. Phase composition and silver release were determined by XRD and ICP-MS. The study showed that, after 50 h in simulated body fluid 0.8-1.8 % of silver of the total silver amount was released from compact HAp/Ag scaffolds, and release kinetics strongly depended on the HAp/Ag preparation method. In vitro antibacterial activity of samples from each method against the bacterial strains Staphylococcus epidermidis and Pseudomonas aeruginosa was approved. Results showed that, in the case of using Ca(OH)2, H3PO4 and AgNO3 as raw materials for HAp/Ag synthesis, higher antibacterial activity towards both bacterial strains could be obtained. PMID:24170340

  9. On the synthesis of tailored biomimetic hydroxyapatite nanoplates through a bioinspired approach in the presence of collagen or chitosan and L-arginine.

    PubMed

    Tsetsekou, A; Brasinika, D; Vaou, V; Chatzitheodoridis, E

    2014-10-01

    Controlling the structure of hydroxyapatite nanocrystals is vital for acquiring a consistent product. In an effort to synthesize crystals mimicking the morphology of natural bone's apatite, a bioinspired process was developed based on the use of a natural biomacromolecule, collagen or chitosan, in conjunction with l-arginine to direct the formation of hydroxyapatite from H3PO4 and Ca(OH)2. Different cases were investigated by employing various concentrations of the precursors and two molar ratios of Ca/P 1/1 and 10/6. The reaction was carried out at basic pH conditions and at biomimetic temperature (40°C). The resulting aqueous suspensions were characterized in terms of their rheological behavior, whereas the derived powders were fully evaluated by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis and Raman spectroscopy. The analysis showed that in all cases, the only phase detected was hydroxyapatite of a plate-like morphology very similar to that of natural apatite. The homogeneity of the morphology and the crystal size distribution depend on the precursors' final concentration with the mean size ranging from 5 nm up to 20 nm. The powder that demonstrated the best characteristics in terms of homogeneity was that produced in the presence of collagen for molar ratio of Ca/P 1/1. PMID:25175250

  10. Determination of the E-pO 2- stability diagram of plutonium in the molten LiCl-KCl eutectic at 450 °C

    NASA Astrophysics Data System (ADS)

    Caravaca, Concha; Laplace, Annabelle; Vermeulen, Jackie; Lacquement, Jérôme

    2008-07-01

    Plutonium trichloride solution in the molten LiCl-KCl eutectic was prepared by carbochlorination of plutonium oxide. Kinetics of this reaction was compared in different conditions in the range of 443-550 °C. Using this molten salt solution, the redox potential of the Pu(III)/Pu couple at inert tungsten electrode was measured at 450 °C by electromotive force measurement and was found to be E?? = -2.76 V vs. the Cl2(g)(1 atm)/Cl- reference electrode (molar fraction scale). Reaction between plutonium trichloride and oxide ions was studied by potentiometric titration, using yttria stabilized electrodes. In our experimental conditions, the titration curves indicate the precipitation of the sesquioxide Pu2O3. The solubility product cologarithm calculated from these curves is found to be pKs(Pu2O3) = 22.8 ± 1.1 (molality scale). Using the experimentally obtained values for E??, activity coefficient and pKs joined to the published thermodynamic data, the stability phase diagram of the Pu-O species was then drawn.

  11. Experimental Na/K exchange between alkali feldspar and an NaCl-KCl salt melt: chemically induced fracturing and element partitioning

    NASA Astrophysics Data System (ADS)

    Neusser, G.; Abart, R.; Fischer, F. D.; Harlov, D.; Norberg, N.

    2012-08-01

    The exchange of Na+ and K+ between alkali feldspar and a NaCl-KCl salt melt has been investigated experimentally. Run conditions were at ambient pressure and 850 °C as well as 1,000 °C. Cation exchange occurred by interdiffusion of Na+ and K+ on the feldspar sub-lattice, while the Si-Al framework remained unaffected. Due to the compositional dependence of the lattice parameters compositional heterogeneities resulting from Na+/K+ interdiffusion induced coherency stress and associated fracturing. Depending on the sense of chemical shift, different crack patterns developed. For the geometrically most regular case that developed when potassic alkali feldspar was shifted toward more sodium-rich compositions, a prominent set of cracks corresponding to tension cracks opened perpendicular to the direction of maximum tensile stress and did not follow any of the feldspar cleavage planes. The critical stress needed to initiate fracturing in a general direction of the feldspar lattice was estimated at ?0.35 GPa. Fracturing provided fast pathways for penetration of salt melt or vapor into grain interiors enhancing overall cation exchange. The Na/K partitioning between feldspar and the salt melt attained equilibrium values in the exchanged portions of the grains allowing for extraction of the alkali feldspar mixing properties.

  12. Convective solution transport -- An improved technique for the growth of big crystals of the superconducting {alpha}-FeSe using KCl as solvent

    SciTech Connect

    Rao, S. M.; Ling, M. C.; Ke, C. T.; Chen, T. C.; Chen, C. L.; Huang, T. W.; Wu, M. K.; Mok, B. H.; Wu, T. B.; Tsai, I.-M.; Lin, Y.-L.; Liu, H. L.; Hsu, F. C.

    2011-12-01

    An improved technique of convective solution transport using KCl as solvent at 840-790 deg. C (where mass transport takes place across a vertical temperature gradient) is described for the growth of crystals of the recently discovered superconductor {alpha}-FeSe{sub x} (x = 1-0.8). The crystals were annealed in situ at 400-350 deg. C for 20-30 h to improve the superconducting properties. Hexagonal plate like crystals measuring 5-6 mm across and 0.25-0.5 mm thick were obtained. High resolution transmission electron microscopy (HRTEM) measurements show good crystallinity and the energy dispersive x-ray analysis (EDX) gives a composition very close to the starting powders. The zero resistance temperature of the crystals was found to increase from 6.5 to 9 K as the composition is decreased from x = 0.95 to 0.9 and decrease thereafter. Similar behavior was also observed in the powder x-ray diffraction (XRD) patterns and Raman spectra with the main peak shifting to higher value until 0.9 and decrease thereafter. In addition the XRD patterns show reducing hexagonal phase reflections as x decreases to 0.9. Anisotropic magnetic behavior was observed when the magnetic field is applied parallel and perpendicular to the (101) face.

  13. Effect of KCl, NaCl and CaCl{sub 2} mixture on volume combustion synthesis of TiB{sub 2} nanoparticles

    SciTech Connect

    Nekahi, Atiye; Firoozi, Sadegh

    2011-09-15

    Highlights: {yields} A low melting diluent lowers the ignition temperature in combustion synthesis. {yields} Deagglomerated synthesized products are formed as the result of diluent addition. {yields} Addition of 45% salt mixture resulted in formation of 70 nm TiB{sub 2} nanoparticles. {yields} Thermodynamically unstable Mg{sub 2}TiO{sub 4} and Mg{sub 3}B{sub 2}O{sub 6} by-products were formed. {yields} Small change in particle size was observed with addition of salt mixture. -- Abstract: Preparation of titanium diboride (TiB{sub 2}) nanoparticles was carried out by volume combustion synthesis. TiO{sub 2}, B{sub 2}O{sub 3} and elemental Mg were mixed with 0-60% salt mixture of KCl, NaCl and CaCl{sub 2} with increment of 15% as a low melting temperature diluent. Compressed samples were synthesized in a tubular furnace at a constant heating rate under argon atmosphere. Thermal analysis of the process showed that the addition of the low melting temperature salts mixture led to a significant decrease in ignition and combustion temperatures. Synthesized samples were then leached by nitric and hydrochloric acids to remove impurities. The samples were examined by XRD, SEM and DLS analysis. The results showed the formation of fine deagglomerated particles with the addition of the salts mixture. The results revealed that 45% salts mixture had the smallest average particle size of about 90 nm.

  14. Optical properties of Eu2+-ions immersed as substitutional impurities in a novel spatially-coherent composite host obtained from a melt of KCl, KBr and KI

    NASA Astrophysics Data System (ADS)

    Cordero-Borboa, A. E.; Flores-Jiménez, C.; Campos-González, M. A.; Hernández-Alcántara, J. M.; Murrieta-Sánchez, H.

    2012-10-01

    The optical properties of doping Eu2+-ions in a novel composite host, consisting of a spatially-coherent aggregate of crystallites of KBr(0.097):KI(0.903) and KBr(0.459):KCl(0.511):KI(0.030), are investigated. The absorption spectrum consists of two broad absorption bands peaking at 353 and 279 nm while the fluorescence spectrum has a single emission band peaking at 422 nm. These spectra, formed by the spectral contributions from the phases in the composite, are similar in overall shape to the spectra of the Eu2+-doped alkali halides used as mother salts, indicating that they are similar in electronic origin. However, in relation to these alkali halides, the phases in the Eu2+-doped composite have low 10Dq-splittings (5684 and 8034 cm-1), low 5d-level barycentre shifts (corresponding to decrements of about -3351, -2839, and -1823 cm-1, respectively, for one of the phases in the composite, and -2411, -1899 and -916 cm-1, respectively, for the other) and low Stokes shifts (4632 and 5496 cm-1). Such low values are discussed to be due to the effect of the mixed ionic character of the impurity environment on the local crystal field as well as to an impurity preference for host cation lattice sites where an iodide ion is nearby to lie at.

  15. Visible and near-IR spectroscopic studies of uranium(IV) oxychloride in a MgCl{sub 2}-KCl melt

    SciTech Connect

    Dai, S.; Toth, L.M.; Del Cul, G.D.; Metcalf, D.H.

    1995-01-04

    Although the chemistry of uranium(IV) chloride complexes in molten chloride melts has been widely investigated, no studies of uranium(IV) oxychloride complexes in these melts have appeared, with the exception of a recent paper from this laboratory. In that paper, visible and near-IR absorption bands overlapping with those of the uranium(IV) chloride complex are attributed to oxychloride species. Attempts have been made to prepare solutions containing uranium oxychloride by a direct dissolution of UOCl{sub 2} into solvents such as water, acids, and molten pyridinium chloride. However, only uranium(IV) chloride complex species are recovered. This led Ewing to conclude that the uranium-oxygen bond in UOCl{sub 2} is stabilized only in the solid state probably by the lattice energy of the crystal. Here the authors want to report, for the first time, the visible and near-IR spectra of uranium oxychloride in molten MgCl{sub 2}-KCl without interference from those of uranium(IV) chloride complexes. In addition, experimental evidence is provided to confirm that the new uranium(IV) species is an oxygen-containing chloride complex.

  16. Regulated phosphorylation of the K-Cl cotransporter KCC3 is a molecular switch of intracellular potassium content and cell volume homeostasis

    PubMed Central

    Adragna, Norma C.; Ravilla, Nagendra B.; Lauf, Peter K.; Begum, Gulnaz; Khanna, Arjun R.; Sun, Dandan; Kahle, Kristopher T.

    2015-01-01

    The defense of cell volume against excessive shrinkage or swelling is a requirement for cell function and organismal survival. Cell swelling triggers a coordinated homeostatic response termed regulatory volume decrease (RVD), resulting in K+ and Cl? efflux via activation of K+ channels, volume-regulated anion channels (VRACs), and the K+-Cl? cotransporters, including KCC3. Here, we show genetic alanine (Ala) substitution at threonines (Thr) 991 and 1048 in the KCC3a isoform carboxyl-terminus, preventing inhibitory phosphorylation at these sites, not only significantly up-regulates KCC3a activity up to 25-fold in normally inhibitory isotonic conditions, but is also accompanied by reversal of activity of the related bumetanide-sensitive Na+-K+-2Cl? cotransporter isoform 1 (NKCC1). This results in a rapid (<10 min) and significant (>90%) reduction in intracellular K+ content (Ki) via both Cl-dependent (KCC3a + NKCC1) and Cl-independent [DCPIB (VRAC inhibitor)-sensitive] pathways, which collectively renders cells less prone to acute swelling in hypotonic osmotic stress. Together, these data demonstrate the phosphorylation state of Thr991/Thr1048 in KCC3a encodes a potent switch of transporter activity, Ki homeostasis, and cell volume regulation, and reveal novel observations into the functional interaction among ion transport molecules involved in RVD. PMID:26217182

  17. Isothermal evaporation process simulation using the Pitzer model for the Quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K

    DOE PAGESBeta

    Meng, Lingzong; Gruszkiewicz, Miroslaw S.; Deng, Tianlong; Guo, Yafei; Li, Dan

    2015-08-05

    In this study, the Pitzer thermodynamic model for solid-liquid equilibria in the quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K was constructed by selecting the proper parameters for the subsystems in the literature. The solubility data of the systems NaCl–SrCl2–H2O, KCl–SrCl2–H2O, LiCl–SrCl2–H2O, and NaCl–KCl–SrCl2–H2O were used to evaluate the model. Good agreement between the experimental and calculated solubilities shows that the model is reliable. The Pitzer model for the quinary system at 298.15 K was then used to calculate the component solubilities and conduct computer simulation of isothermal evaporation of the mother liquor for the oilfield brine from Nanyishan district in themore »Qaidam Basin. The evaporation-crystallization path and sequence of salt precipitation, change in concentration and precipitation of lithium, sodium, potassium, and strontium, and water activities during the evaporation process were demonstrated. The salts precipitated from the brine in the order : KCl, NaCl, SrCl2?6H2O, SrCl2?2H2O, and LiCl?H2O. The entire evaporation process may be divided into six stages. In each stage the variation trends for the relationships between ion concentrations or water activities and the evaporation ratio are different. This result of the simulation of brines can be used as a theoretical reference for comprehensive exploitation and utilization of this type of brine resources.« less

  18. Isothermal evaporation process simulation using the Pitzer model for the Quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K

    SciTech Connect

    Meng, Lingzong; Gruszkiewicz, Miroslaw S.; Deng, Tianlong; Guo, Yafei; Li, Dan

    2015-08-05

    In this study, the Pitzer thermodynamic model for solid-liquid equilibria in the quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K was constructed by selecting the proper parameters for the subsystems in the literature. The solubility data of the systems NaCl–SrCl2–H2O, KCl–SrCl2–H2O, LiCl–SrCl2–H2O, and NaCl–KCl–SrCl2–H2O were used to evaluate the model. Good agreement between the experimental and calculated solubilities shows that the model is reliable. The Pitzer model for the quinary system at 298.15 K was then used to calculate the component solubilities and conduct computer simulation of isothermal evaporation of the mother liquor for the oilfield brine from Nanyishan district in the Qaidam Basin. The evaporation-crystallization path and sequence of salt precipitation, change in concentration and precipitation of lithium, sodium, potassium, and strontium, and water activities during the evaporation process were demonstrated. The salts precipitated from the brine in the order : KCl, NaCl, SrCl2?6H2O, SrCl2?2H2O, and LiCl?H2O. The entire evaporation process may be divided into six stages. In each stage the variation trends for the relationships between ion concentrations or water activities and the evaporation ratio are different. This result of the simulation of brines can be used as a theoretical reference for comprehensive exploitation and utilization of this type of brine resources.

  19. I-NERI ANNUAL TECHNICAL PROGRESS REPORT: 2006-002-K, Separation of Fission Products from Molten LiCl-KCl Salt Used for Electrorefining of Metal Fuels

    SciTech Connect

    S. Frank

    2009-09-01

    An attractive alternative to the once-through disposal of electrorefiner salt is to selectively remove the active fission products from the salt and recycle the salt back to the electrorefiner (ER). This would allow salt reuse for some number of cycles before ultimate disposal of the salt in a ceramic waste form. Reuse of ER salt would, thus, greatly reduce the volume of ceramic waste produced during the pyroprocessing of spent nuclear fuel. This final portion of the joint I-NERI research project is to demonstrate the separation of fission products from molten ER salt by two methods previously selected during phase two (FY-08) of this project. The two methods selected were salt/zeolite contacting and rare-earth fission product precipitation by oxygen bubbling. The ER salt used in these tests came from the Mark-IV electrorefiner used to anodically dissolved driver fuel from the EBR-II reactor on the INL site. The tests were performed using the Hot Fuel Dissolution Apparatus (HFDA) located in the main cell of the Hot Fuels Examination Facility (HFEF) at the Materials and Fuels complex on the INL site. Results from these tests were evaluated during a joint meeting of KAERI and INL investigators to provide recommendations as to the future direction of fission product removal from electrorefiner salt that accumulate during spent fuel treatment. Additionally, work continued on kinetic measurements of surrogate quaternary salt systems to provide fundamental kinetics on the ion exchange system and to expand the equilibrium model system developed during the first two phases of this project. The specific objectives of the FY09 I-NERI research activities at the INL include the following: • Perform demonstration tests of the selected KAERI precipitation and INL salt/zeolite contacting processes for fission product removal using radioactive, fission product loaded ER salt • Continue kinetic studies of the quaternary Cs/Sr-LiCl-KCl system to determine the rate of ion exchange during the salt/zeolite contacting process • Compare the adsorption models to experimentally obtained, ER salt results • Evaluate results obtained from the oxygen precipitation and salt/zeolite ion exchange studies to determine the best processes for selective fission-product removal from electrorefiner salt.

  20. Burn rates of TiH2/KClO4/Viton and output testing of NASA SKD26100098-301 pressure cartridges

    NASA Technical Reports Server (NTRS)

    Holy, John A.

    1993-01-01

    The burn rates of the pyrotechnic TiH2/KClO4/Viton with a mass ratio of 30/65/5 have been measured as a function of pressure in nitrogen up to 312 MPa(45 Kpsi). The burn rates were fit to R = a pn, with a = 2.055 cm/sec/MPan and n = 0.472 between 0.15 MPa (22 psi) and 21.6 MPa (3.13 Kpsi) and a = 4.38 cm/sec/MPan and n = 0.266 between 70 MPa (10.15 Kpsi) and 312 MPa (45.25 Kpsi). The decrease in slope at the higher pressures is attributed to a diffusion limited reaction. No acoustically driven flame instabilities or large conductive-to-convective burn transitions were observed. Solid reaction products were analyzed by x-ray diffraction and scanning electron microscopy (SEM). X-ray diffraction detected only TiO2 and KC1. SEM showed that the particle size of the reaction products increased as the nitrogen pressure increased. There were no anomalous characteristics of the burn of this pyrotechnic that could be interpreted as a cause of the o-ring blow-by problem in the forward shear bolt assembly. Three NASA SKD26100098-301 pressure cartridges were fired into a fixed volume vessel that was sealed with an O-ring. A maximum pressure of 181.7 MPa(26,350 psi) was reached in around 100 ,mu sec for two shots fired into a volume of 16.3 cm3(0.996 in3). A maximum pressure of 33,460 psi was reached for one shot fired into a volume of 9.55 cm3(0.583 in3). The O-ring burned through on one shot in the larger volume and leaked on the other two thereby simulating the effects of an O-ring leak. The results imply that the piston in the shear bolt assembly would receive a large impulse even if there was a leak in an O-ring seal.

  1. X-ray absorption studies of ZnCl{sub 2}-PEO and mixed salt ZnCl{sub 2}/KCl-PEO and ZnCl{sub 2}/CsCl-PEO complexes

    SciTech Connect

    McBreen, J.; Yang, X.Q.; Lee, H.S.; Okamoto, Y.

    1996-10-01

    ZnCl{sub 2}[polyethylene oxide (PEO)]{sub 12}, [0.33 ZnCl{sub 2} + 0.67 KCl](PEO){sub 12}, and [0.33 ZnCl{sub 2} + 0.67 CsCl](PEO){sub 12} complexes were studied by X-ray absorption in the temperature range of 25 to 120 C. The results for ZnCl{sub 2} (PEO){sub 12} show that the complex exists mostly as undissociated ZnCl{sub 2} with the Zn atom also coordinated with four O atoms from the PEO. The respective Zn-Cl and Zn-O bond distances are 2.2 and 2.05 {angstrom}. There is an increase in ion pairing with increasing temperature. The results for the mixed salt complexes are consistent with the formation of a mixture of ZnCl{sub 4}{sup 2{minus}} and ZnCl{sub 3}{sup {minus}} complexes with a Zn-Cl bond distance of {approximately} 2.26 {angstrom}. Complex formation differs in [0.33 ZnCl{sub 2} + 0.67 KCl](PEO){sub 12} and [0.33 ZnCl{sub 2} + 0.67 CsCl](PEO){sub 12}. This is attributed to the higher charge density of K{sup +}, which promotes ion pairing and shifts the ZnCl{sub 4}{sup 2{minus}}/ZnCl{sub 3}{sup {minus}} equilibrium.

  2. Experimental and simulation study of salt effects and pressure/density effects on oxygen and hydrogen stable isotope liquid-vapor fractionation for 4-5 molal aqueous NaCl and KCl solutions to 400°C

    NASA Astrophysics Data System (ADS)

    Driesner, T.; Seward, T. M.

    2000-05-01

    Liquid-vapor equilibrium fractionation factors for D/H and 18O/ 16O exchange between concentrated (4.0 to 4.8 molal) aqueous solutions of NaCl and KCl and their respective equilibrium vapor phases have been determined experimentally up to 413°C. In both cases, strong deviations from the pure water liquid-vapor fractionation curves are observed. The D/H fractionation curves of the two salt solutions are almost identical over the entire temperature range studied and are always located below the pure water curve, thus changing the location of the crossover point to about 200°C. The strongest fractionation of deuterium into the vapor phase occurs around 330-350°C. The 18O/ 16O fractionation curves for the two solutions are significantly different. Whereas NaCl has hardly any effect below 200°C and then tends to enrich the heavy isotope in the liquid more strongly than is the case in pure water, KCl causes a depletion of the solution relative to pure water below about 100°C and a relative enrichment above 200°C. Using the combined results of molecular dynamics simulations of water vapor at various temperatures and densities and ab initio calculations of the vibrational frequencies for various water species, we demonstrate that above 200°C, the measured fractionation factors cannot solely be interpreted in terms of isotope effects related to ionic hydration in the solution. The simulations indicate significant contributions from isotope effects resulting from the different vapor pressures/densities of pure water and salt solutions. Furthermore, it is very likely that the density differences between the liquid phases play an important role at high temperatures. The contributions of these two density effects to D/H fractionation increase along the liquid-vapor curve. In contrast, the contribution of isotope effects resulting from ionic hydration decreases with increasing temperature. Evidence is presented that the D/H isotope effect resulting from ionic hydration in a solution of constant density probably follows a normal linear 1/T 2 dependence and that the liquid-vapor data below 200°C can be used to constrain the slope of this line. The vapor density effect contribution to the 18O/ 16O liquid-vapor fractionation is apparently small. In contrast to D/H, the 18O/ 16O isotope effects caused by ionic hydration appear to increase with increasing temperature and are different for NaCl and KCl. The possible molecular causes for the observed trends are discussed.

  3. Impedance of Aqueous Solutions of KCl at the Ultra-low Frequency Range: Use of Cole-Cole Impedance Element to Account for the Frequency Dispersion Peak at 20 mHz

    NASA Astrophysics Data System (ADS)

    Giacometti, José A.; Alves, Neri; Teruya, Márcia Y.

    2015-11-01

    This paper reports on the analysis of dispersion in the imaginary part of impedance often observed at low frequencies in a variety of systems. The experimental data were obtained with an electrolytic cell containing KCl aqueous solution in the frequency range from 0.1 mHz to 10 MHz, where the use of ultra-low frequencies helps clarify the analysis of the imaginary impedance dispersion. It is shown that the low frequency dispersion described in the literature is the tail of a relaxation peak located at f ? 20 mHz. This ultra-low frequency dispersion peak is analyzed with a Cole-Cole impedance element, being associated with the electric double layer at the metal-electrolyte interface. Quantitative information can be extracted for the double layer, including its thickness (˜1 nm) and electrical resistivity (˜50 G?m).

  4. Phosphate-induced metal immobilization in a contaminated site Rocky X. Caoa

    E-print Network

    Ma, Lena

    Phosphate-induced metal immobilization in a contaminated site Rocky X. Caoa , Lena Q. Maa, *, Ming Received 15 April 2002; accepted 11 July 2002 ``Capsule'': A mixture of H3PO4 and phosphate rock Florida. Phosphate was applied at a P/Pb molar ratio of 4.0 with three treatments: 100% of P from H3PO4

  5. Electric conductivities of 1:1 electrolytes in liquid methanol along the liquid-vapor coexistence curve up to the critical temperature. I. NaCl, KCl, and CsCl solutions

    NASA Astrophysics Data System (ADS)

    Hoshina, Taka-aki; Tsuchihashi, Noriaki; Ibuki, Kazuyasu; Ueno, Masakatsu

    2004-03-01

    The molar conductivities ? of NaCl, KCl, and CsCl in liquid methanol were measured in the concentration range of (0.3-2.0)×10-3 mol dm-3 and the temperature range of 60-240 °C along the liquid-vapor coexistence curve. The temperature range corresponds to the solvent density range of (2.78-1.55)?c, where ?c=0.2756 g cm-3 is the critical density of methanol. The concentration dependence of ? at each temperature and density (pressure) has been analyzed by the Fuoss-Chen-Justice equation to obtain the limiting molar conductivity ?0 and the molar association constant KA. For all the electrolytes studied, ?0 increased almost linearly with decreasing density at densities above 2.0?c, while the opposite tendency was observed at lower densities. The relative contribution of the nonhydrodynamic effect on the translational friction coefficient ? was estimated in terms of ??/?, where the residual friction coefficient ?? is the difference between ? and the Stokes friction coefficient ?S. At densities above 2.0?c, ??/? increased with decreasing density though ? and ?? decrease, and the tendencies are common for all the ions studied. The density dependences of ? and ??/? were explained well by the Hubbard-Onsager (HO) dielectric friction theory based on the sphere-in-continuum model. At densities below 2.0?c, however, the experimental results cannot be explained by the HO theory.

  6. Quartz solubility in the two-phase and critical region of the NaCl KCl H2O system: Implications for submarine hydrothermal vent systems at 9°50?N East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Foustoukos, D. I.; Seyfried, W. E.

    2007-01-01

    Experiments were performed to investigate quartz solubility in Cl-bearing aqueous solutions at temperature (365-430 °C) and pressure conditions (219-381 bars) near and within the two-phase region of the NaCl-KCl-H 2O system. Dissolved SiO 2 concentrations increased with pressure along a given isotherm, although the magnitude of this decreased with increasing proximity to the two-phase boundary. Upon intersection of the two-phase boundary, however, significant concentrations of dissolved SiO 2 characterized vapor-rich fluids at both subcritical and supercritical conditions. For these fluids, dissolved silica concentrations ranged from 2.81 to 14.6 mmolal, increasing with dissolved chloride concentration. The experimental data permit regression of a density-based relationship, taking account of non-ideal activity-concentration effects, which can be used to better constrain temperatures and pressures from dissolved SiO 2 and chloride in high temperature vent fluids at mid-ocean ridges. Accordingly, pressure and temperature conditions in subseafloor hydrothermal reaction zones at 9°50'N East Pacific Rise (EPR) were estimated applying data from this experimental study to interval (1991-2002) and new field data (2004). Results indicate reaction zone at conditions ranging from 420 to 430 °C at 600 to 1500 m below seafloor. Thus, conditions predicted for 9°50'N East Pacific Rise (EPR) vent fluids suggest that supercritical phase separation might be more common than previously thought.

  7. Anisotropy of longitudinal ultrasonic absorption in anharmonic processes of scattering in Ge, Si, InSb, MgO, and KCl cubic crystals: The role of damping of phonon states

    NASA Astrophysics Data System (ADS)

    Kuleyev, I. G.; Kuleyev, I. I.

    2010-07-01

    The relaxation of longitudinal phonons and absorption of ultrasound in cubic crystals with positive (Ge, Si, InSb, MgO) and negative (KCl) anisotropies of the second-order elastic moduli have been investigated. The scattering processes occurring with the participation of three longitudinal phonons (the LLL mechanism) and the processes of scattering of a longitudinal phonon by two transverse thermal phonons (the LTT mechanism) have been considered in terms of the anisotropic-continuum model. The influence of damping of phonon states on the anisotropy of longitudinal ultrasonic absorption has been examined. The specific features of phonon scattering and the influence of anisotropy of the harmonic and anharmonic energies of the cubic crystals on the ultrasonic absorption have been analyzed. In contrast to the previously performed calculations, the influence of cubic anisotropy of the harmonic and anharmonic energies of the phonon system on the relaxation processes has been exactly taken into account in the present study. The results of the calculations have been compared with experimental data.

  8. Electric conductivities of 1:1 electrolytes in liquid methanol along the liquid-vapor coexistence curve up to the critical temperature. I. NaCl, KCl, and CsCl solutions.

    PubMed

    Hoshina, Taka-Aki; Tsuchihashi, Noriaki; Ibuki, Kazuyasu; Ueno, Masakatsu

    2004-03-01

    The molar conductivities Lambda of NaCl, KCl, and CsCl in liquid methanol were measured in the concentration range of (0.3-2.0) x 10(-3) mol dm(-3) and the temperature range of 60-240 degrees C along the liquid-vapor coexistence curve. The temperature range corresponds to the solvent density range of (2.78-1.55)rhoc, where rhoc = 0.2756 g cm(-3) is the critical density of methanol. The concentration dependence of Lambda at each temperature and density (pressure) has been analyzed by the Fuoss-Chen-Justice equation to obtain the limiting molar conductivity Lambda0 and the molar association constant KA. For all the electrolytes studied, Lambda0 increased almost linearly with decreasing density at densities above 2.0rhoc, while the opposite tendency was observed at lower densities. The relative contribution of the nonhydrodynamic effect on the translational friction coefficient zeta was estimated in terms of Deltazeta/zeta, where the residual friction coefficient Deltazeta is the difference between zeta and the Stokes friction coefficient zetaS. At densities above 2.0rhoc, Deltazeta/zeta increased with decreasing density though zeta and Deltazeta decrease, and the tendencies are common for all the ions studied. The density dependences of zeta and Deltazeta/zeta were explained well by the Hubbard-Onsager (HO) dielectric friction theory based on the sphere-in-continuum model. At densities below 2.0rhoc, however, the experimental results cannot be explained by the HO theory. PMID:15268605

  9. Hydrogen defects in proton bombarded KCl.

    NASA Technical Reports Server (NTRS)

    Chu, Y. H.; Friauf, R. J.; Zeller, E. J.

    1972-01-01

    Optical absorption bands are observed in the UV and IR proton bombarded potassium chloride at liquid nitrogen temperature. It is demonstrated that the absorption is due to trapped protons, and the largest UV band has been identified with the U center.

  10. An Experimental Study of Magnetite Solubility as a Function of Pressure Along the Dewpoint Curve in the NaCl-, KCl-, HCl-H2O-Melt System.

    NASA Astrophysics Data System (ADS)

    Simon, A. C.

    2001-12-01

    Magnetite (Mt) is a ubiquitous phase in magmatic-hydrothermal ore deposits and, thus, any model which aims to predict the evolving physical chemistry of porphyry-ore deposit environments must incorporate data on the equilibria that control the precipitation of Mt in such systems. Extant experimental data indicate that Mt solubility is controlled via the equilibrium Fe3O4Mt + 6HClV + H2V = 3FeCl2V + 4H2OV (Chou and Eugster, 1977, AJS, p 1296); however their experiments were performed at T=500-650° C by equilibrating Mt with a HCl-bearing supercritical aqueous fluid (NaCl-, KCl-free). Conversely, data from some natural Fe-bearing fluid inclusions have evinced that initial temperatures of magmatic volatile phases (MVP) in magmatic-hydrothermal environments may exceed 800° C, possibly even approaching 900° C, in the presence of melt (Clark and Arancibia, 1995, Giant Ore Deposits-II Conference, p. 511). Thus, there currently are no data constraining Mt solubility in the high-temperature regime obtained in natural magmatic systems. Additionally, there are no data on Mt solubility as a function of changes in the chemistry of the MVP. In the system NaCl-H2O, the composition and, thus, the density of brine-saturated vapor change significantly as a function of pressure along a given isotherm and the components KCl and HCl act to shift the limbs of the solvii (Bodnar et al., 1985, GCA, p 1861; Anderko and Pitzer, 1993, GCA, p 1657; Shinohara and Fujimoto, 1994, GCA, p 4857). The absence of data constraining Mt solubility as a function of pressure along a given isotherm, the resultant change in composition and density, as well as deviations in the Na:K:H ratio of the MVP hinder the development of forward models of magmatic-hydrothermal systems. In order to provide these critical data constraining Mt solubility in geologically reasonable magmatic systems we have performed a set of experiments as a function of pressure in the vapor-only field near the 800° C isotherm in the NaCl-H2O system. Natural Mt (aFe3O4 ~1), a synthetic haplogranitic minimum melt (100 MPa) and an aqueous phase (molar K:Na:H=1) were reacted in Au capsules in rapid-quench Stellite-25 vessels, using water as the pressure medium, at 800° C, log fO2 controlled by the NNO buffer, pressures of 100 and 120 MPa, and aqueous salinities of 1.8 and 3.0 wt. % NaCl equivalent, respectively. In all experiments the mass ratio of Mt:melt:fluid was 1:1:4. Detailed petrographic examination of run products did not reveal the presence of brine inclusions; however, fluid inclusions do contain opaque phases. Using the newly determined mFeCl2 (0.0345 at 100 MPa and 0.0359 at 120 MPa) and mHCl (0.0769 at 100 MPa and 0.0947 at 120 MPa) in the quenched MVP and the known fugacities of H2O (? =1) and H2 (? =1) at P and T, apparent equilibrium constants were calculated as log K' = (CFeCl2)3 \\times (fH2O)4 \\div (CHCl)6 \\times fH2. The values of log K' are 1.605 at 100 MPa and 13.01 at 120 MPa. K is fixed for a given P and T except for the effect of activity coefficients for HCl and FeCl2. The values of log K obtained in this study will facilitate more detailed characterization of the chemistry of magmatic-hydrothermal MVPs; both fossil MVPs and those that obtain in modern geothermal reservoirs. Determination of P, T, fH2 and mFeCl2 in fluid inclusions will allow for the direct calculation of a model HCl concentration in the MVP.

  11. LABORATORY EXPERIMENT 4 Alkalimetric Titration of an Acid Mixture

    E-print Network

    Nazarenko, Alexander

    LABORATORY EXPERIMENT 4 Alkalimetric Titration of an Acid Mixture In this experiment to semi-automatic volumetric analysis and potentiometric titrations. Phosphoric Acid, H3PO4 (pK1= 2.16, pK2 = 7.16, pK3=12.3). Phosphoric acid can be titrated as a monobasic acid: H3PO4 + NaOH NaH2PO4 + H2

  12. Pretreating wheat straw by the concentrated phosphoric acid plus hydrogen peroxide (PHP): Investigations on pretreatment conditions and structure changes.

    PubMed

    Wang, Qing; Hu, Jinguang; Shen, Fei; Mei, Zili; Yang, Gang; Zhang, Yanzong; Hu, Yaodong; Zhang, Jing; Deng, Shihuai

    2016-01-01

    Wheat straw was pretreated by PHP (the concentrated H3PO4 plus H2O2) to clarify effects of temperature, time and H3PO4 proportion on hemicellulose removal, delignification, cellulose recovery and enzymatic digestibility. Overall, hemicellulose removal was intensified by PHP comparing to the concentrated H3PO4. Moreover, efficient delignification specially happened in PHP pretreatment. Hemicellulose removal and delignification by PHP positively responded to temperature and time. Increasing H3PO4 proportion in PHP can promote hemicellulose removal, however, decrease the delignification. Maximum hemicellulose removal and delignification were achieved at 100% and 83.7% by PHP. Enzymatic digestibility of PHP-pretreated wheat straw was greatly improved by increasing temperature, time and H3PO4 proportion, and complete hydrolysis can be achieved consequently. As temperature of 30-40°C, time of 2.0h and H3PO4 proportion of 60% were employed, more than 92% cellulose was retained in the pretreated wheat straw, and 29.1-32.6g glucose can be harvested from 100g wheat straw. PMID:26264398

  13. Production of Long-Lived H{sub 2}{sup -}, HD{sup -}, and D{sub 2}{sup -} during Grazing Scattering Collisions of H{sub 2}{sup +}, H{sub 3}{sup +}, D{sub 2}{sup +}, D{sub 3}{sup +} and D{sub 2}H{sup +} Ions with KBr, KCl, and LiF Surfaces

    SciTech Connect

    Seely, D. G.; Meyer, F. W.; Zhang, H.; Havener, C. C.

    2009-03-10

    We have investigated atomic and molecular anion production from singly charged atomic and molecular hydrogen, deuterium, and mixed isotope beams during grazing interactions with large area KBr, KCl, and LiF single crystal targets in the incident energy range 4-22.5 keV. Electron capture and, in the case of incident molecular ions, dissociation occur during the grazing interactions without appreciable angular straggling or change in velocity. As a result, atomic and molecular cation and anion interaction products are strongly peaked in the specular reflection direction, and, in case of dissociation products, at the fractional kinetic energies determined by the product fragment mass to incident mass ratios. A large-acceptance electrostatic analysis and detection system is used to collect the charged scattering products with high efficiency. Of particular interest is the production of metastable molecular ions H{sub 2}{sup -}, HD{sup -}, and D{sub 2}{sup -}. By comparing molecular anion yields obtained from incident hydrogen, deuterium and mixed isotope molecular ions, effects arising from isobaric contamination are seen for some incident molecular species.

  14. Adsorption characteristics of malachite green on activated carbon derived from rice husks produced by chemical-thermal process.

    PubMed

    Rahman, I A; Saad, B; Shaidan, S; Sya Rizal, E S

    2005-09-01

    Phosphoric acid (H(3)PO(4)) and sodium hydroxide (NaOH) treated rice husks, followed by carbonization in a flowing nitrogen were used to study the adsorption of malachite green (MG) in aqueous solution. The effect of adsorption on contact time, concentration of MG and adsorbent dosage of the samples treated or carbonized at different temperatures were investigated. The results reveal that the optimum carbonization temperature is 500 degrees C in order to obtain adsorption capacity that is comparable to the commercial activated carbon for the husks treated by H(3)PO(4). It is interesting to note that MG adsorbed preferably on carbon-rich than on silica rich-sites. It is found that the behaviour of H(3)PO(4) treated absorbent followed both the Langmuir and Freundlich models while NaOH treated best fitted to only the Langmuir model. PMID:15978990

  15. Ab Initio Study of KCl and NaCl Clusters

    NASA Astrophysics Data System (ADS)

    Brownrigg, Clifton; Hira, Ajit; Pacheco, Jose; Salazar, Justin

    2013-03-01

    We continue our interest in the theoretical study of molecular clusters to examine the chemical properties of small KnCln and NanCln clusters (n = 2 - 15). The potentially important role of these molecular species in biochemical and medicinal processes is well known. This work applies the hybrid ab initio methods of quantum chemistry to derive the different alkali-halide (MnHn) geometries. Of particular interest is the competition between hexagonal ring geometries and rock salt structures. Electronic energies, rotational constants, dipole moments, and vibrational frequencies for these geometries are calculated. Magic numbers for cluster stability are identified and are related to the property of cluster compactness. Mapping of the singlet, triplet, and quintet, potential energy surfaces is performed. Calculations have been performed to examine the interactions of these clusters with some atoms and molecules of biological interest, including O, O2, and Fe. The potential for design of new medicinal drugs is explored.

  16. Quantum Theoretical Study of KCl and LiCl Clusters

    NASA Astrophysics Data System (ADS)

    Koetter, Ted; Hira, Ajit; Salazar, Justin; Jaramillo, Danelle

    2014-03-01

    This research focuses on the theoretical study of molecular clusters to examine the chemical properties of small KnClnandLinCln clusters (n = 2 - 20). The potentially important role of these molecular species in biochemical and medicinal processes is well known. This work applies the hybrid ab initio methods of quantum chemistry to derive the different alkali-halide (MnHn) geometries. Of particular interest is the competition between hexagonal ring geometries and rock salt structures. Electronic energies, rotational constants, dipole moments, and vibrational frequencies for these geometries are calculated. Magic numbers for cluster stability are identified and are related to the property of cluster compactness. Mapping of the singlet, triplet, and quintet, potential energy surfaces is performed. Calculations were performed to examine the interactions of these clusters with some atoms and molecules of biological interest, including O, O2, and Fe. Potential design of new medicinal drugs is explored.

  17. Materials Data on KCl (SG:225) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  18. Materials Data on KCl (SG:221) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  19. Dielectric Studies on HgCl2: 2 KCl Crystals

    NASA Astrophysics Data System (ADS)

    Sastry, S. Sreehari; Rao, V. Venkata; Satyanandam, G.; Raj, T. F. Sundar

    1988-09-01

    The dielectric properties of HgCl2 : 2 K Cl crystals have been measured as a function of frequency (102-105 Hz) and temperature (304-415 K), along with the d.c. conductivity, in two mutually perpendicular (X and Y) directions. Along the X direction a simple Debye type relaxation mecha­nism is observed at 304 K. A large dielectric anisotropy has been noticed at all frequencies and temperatures. Phase transitions of ferroelectric and order-disorder type are observed along the X and Y direction, respectively.

  20. www.kcl.ac.uk/connect Main College address

    E-print Network

    Applebaum, David

    and College administration are based in the nearby James Clerk Maxwell Building . Students and staff alike desks located on the ground floors of both the Franklin-Wilkins and James Clerk Maxwell Buildings. #12

  1. Elution behavior of poly(lactide-co-succinimide) copolymers studied by SEC-MALS.

    PubMed

    Gricar, Maja; Zigon, Majda; Zagar, Ema

    2009-03-01

    We synthesized poly(lactide-co-succinimide) (PLS) copolymers with the ratio of lactide to succinimide units of 3:1 and 6.5:1 and studied their elution behavior by size exclusion chromatography with an on-line light-scattering detection. Since the copolymers contain a certain amount of carboxyl groups, they behave as ionomers in N,N-dimethylacetamide (DMAc) and show a typical polyelectrolyte (PE) effect. The PE effect was eliminated by the addition of simple electrolyte like LiBr, H(3)PO(4), or both in DMAc. The efficiency of the additive decreases in the order: LiBr > LiBr + H(3)PO(4) > H(3)PO(4). The ionic strength of the 0.1 M LiBr/DMAc was high enough for the onset of hydrophobic interactions of PLS lactic acid segments intermolecularly as well as with the column packing material. The drawback of the LiBr + H(3)PO(4)/DMAc solvent system is a rather high intensity of the system peaks, which are imposed on the right side of the copolymer signal. System peaks strongly influence the determination of number and to a lesser extent the weight average molar masses of PLS copolymers. An addition of only H(3)PO(4) in high enough concentration to DMAc (0.05 and 0.1 M) successfully eliminated the PE effect of the 6.5:1 PLS copolymer. On the contrary, the PE effect of the 3:1 PLS copolymer having higher charge density compared to 6.5:1 PLS copolymer cannot be entirely canceled out in any of the H(3)PO(4)/DMAc solutions examined. PMID:19104780

  2. Technology development for phosphoric acid fuel cell powerplant, phase 2

    NASA Technical Reports Server (NTRS)

    Christner, L.

    1979-01-01

    A technique for producing an acid inventory control member by spraying FEP onto a partially screened carbon paper backing is discussed. Theoretical analysis of the acid management indicates that the vapor composition of 103% H3PO4 is approximately 1.0 ppm P4O10. An SEM evaluation of corrosion resistance of phenolic resins and graphite/phenolic resin composites in H3PO4 at 185 C shows specific surface etching. Carbonization of graphite/phenolic bipolar plates is achieved without blistering.

  3. Characterization of flue gas cleaning residues from European solid waste incinerators: assessment of various Ca-based sorbent processes.

    PubMed

    Bodénan, F; Deniard, Ph

    2003-05-01

    For the first time, a set of samples of European flue gas cleaning residues, mainly from the incineration of municipal solid waste (MSW), has undergone a mineralogical study. The residues are the result of the neutralization of acid flue gases by lime, the predominant method adopted in Europe, using dry and semi-dry washing processes. The study protocol combines physico-chemical analytical techniques (XRD, FTIR, DSC/TGA) and global chemical analysis enabling identification of the chemical composition of the main constituents, particularly chlorinated Ca-based phases, as well as establishment of modal distributions of the represented phases, both crystalline and amorphous. The samples are slightly hydrated and values vary for trapped Cl, S and even CO(2). The main crystalline phases are NaCl, KCl, CaSO(4), CaCO(3), Ca(OH)(2) and calcium hydroxychloride CaOHCl. CaOHCl is the main chlorine phase, regardless of the treatment process, filtration mode, and specific surface of the Ca-based sorbent. This phase develops during neutralization of HCl by excess lime present according to the reaction Ca(OH)(2)+HCl-->CaOHCl+H(2)O, to the detriment of a complete yield involving the two lime OH groups with formation of CaCl(2).2H(2)O. In addition, it seems that gas temperatures above 150 degrees C increase competition between lime-based neutralization of HCl, SO(2) acid flue gases and CO(2) trapping, thus reducing washing efficiency. PMID:12597999

  4. Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soft drink consumption may have adverse effects on BMD, but studies have shown mixed results. In addition to displacing healthier beverages, colas contain caffeine and phosphoric acid (H3PO4), which may adversely affect bone. We hypothesized that consumption of cola is associated with lower BMD. BMD...

  5. High temperature dilute phosphoric acid pretreatment of corn stover for furfural and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Furfural was produced from corn stover by one stage pretreatment process using dilute H3PO4 and solid residues following furfural production were used for ethanol production by Saccharomyces cerevisiae NRRL- Y2034. A series of experiments were conducted at varied temperatures (140-200 oC) and acid ...

  6. Production of ethanol and furfural from corn stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has potential for economical production of biofuels and value-added chemicals. The conversion of corn stover to sugars involves pretreatment and enzymatic hydrolysis. We have optimized hydrothermal, dilute H2SO4 and dilute H3PO4 pretreatments of corn stover for enzymatic saccharificati...

  7. Response surface optimization of corn stover pretreatment using dilute phosphoric acid for enzymatic hydrolysis and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dilute H3PO4 (0.0 - 2.0%, v/v) was used to pretreat corn stover (10%, w/w) for conversion to ethanol. Pretreatment conditions were optimized for temperature, acid loading, and time using a central composite design. Optimal pretreatment conditions were chosen to promote sugar yields following enzym...

  8. Polysaccharides isolated from sugar beet pulp by quaternization under acidic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugar beet pulp was extracted and chemically modified under acidic conditions using glycidyltrimethylammonium chloride in the presence of trifuoroacetic (TFA), HCl or H3PO4. The goal was to find out how the type of acid used and quaternization could affect the yield of soluble polysaccharide, its mo...

  9. Total and Dissolved Organic and Inorganic Carbon The Shimadzu TOC-L uses a high temperature combustion method to analyze aqueous samples

    E-print Network

    Boynton, Walter R.

    breaks down organic carbon into carbon dioxide (CO2). The CO2 is carried by ultra-pure air to a non- dispersive infrared detector (NDIR) where CO2 is detected. The method used is EPA 415.1. The Shimadzu TOC the TIC concentration. Samples are injected into 25% v/v Phosphoric Acid (H3PO4), and the released CO2

  10. Revised: 2009-12-15 Source: www.microchemicals.eu/technical_information

    E-print Network

    Yoo, S. J. Ben

    compounds for dissolving Al2 O3 as well as for etching (or, respectively, oxidizing) aluminium. Aluminium Etching Mechanism Typical Aluminium etchants contain mixtures of 1-5 % HNO3 * (for Al oxidation), 65 rate of H3 PO4 /HNO3 mixtures strongly depends on the temperature (fig. right-hand for a certain

  11. Preparation and dispersion of NiCu composite nanoparticles Yu-Guo Guo,y Li-Jun Wan,* Jian-Ru Gong and Chun-Li Bai*

    E-print Network

    Gong, Jian Ru

    to produce highly crystalline sand- wich Cu­Ni­Cu composite nanoparticles. 2. Experimental Fabrication of the sandwich cylinder-shaped Cu­Ni­Cu nano- particles was carried out by using the process shown schemati LÀ1 CuCl2 mixed solution. Then, the barrier layer was dissolved in 5% H3PO4 . Finally, a silver film

  12. Arg-Arg-Src Peptide Kinase Activity Assay For Tyrosine Kinases

    E-print Network

    Pike, Linda J.

    easily accomplished by placing a wire basket in a 500 ml beaker with a stir bar that fits underneath the basket. 75 mM H3PO4 is added to the beaker and the papers are placed in the basket immediately after spotting. The papers can be retrieved by removing the basket from the beaker. The wash buffer is discarded

  13. Reversible Intercalation of Hexagonal Boron Nitride with Brnsted Nina I. Kovtyukhova,*,

    E-print Network

    be formed by simple thermal drying of h-BN in Brønsted acids H2SO4, H3PO4, and HClO4. X-ray photoelectron process. INTRODUCTION Intercalation reactions of lamellar solids form the basis of a number of practical to individual atomic/ molecular layers.4-10 In this family of materials, graphene,11 transition metal

  14. Production of cellulose phosphate from oil palm empty fruit bunch: Effect of chemical ratio

    NASA Astrophysics Data System (ADS)

    Rohaizu, R.; Wanrosli, W. D.

    2015-06-01

    Cellulose phosphate was synthesized from oil palm biomass residue that has the potential to represent a considerable added value product for the oil palm biomass utilization. Cellulose phosphate (CP) is prepared viaa phosphorylation process using the H3PO4/P2O5/Et3PO4/hexanol sequence using oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) as the starting material. Various factors affect its synthesis; one of them which is the subject of this investigation is the orthophosphoric acid (H3PO4) to triethylphosphate(Et3PO4) ratio which have the capability to increase the phosphorus content of CP. It is believed that during this reaction, the esterification of the free hydroxyl groups of the cellulose occurred. The H3PO4/Et3PO4 ratios applied were 0.16, 1.00, and 1.84. The effect of the H3PO4/Et3PO4 ratio on phosphorus content, yield, water swelling and molecular structure of CP are discussed.

  15. Antimicrobial effect of calcium hydroxide as an intracanal medicament in root canal treatment: a literature review - Part I. In vitro studies

    PubMed Central

    2014-01-01

    The goal of endodontic treatment is the prevention and control of pulpal and periradicular infections. Calcium hydroxide (Ca(OH)2) has been widely used in endodontics as an intracanal medicament to eliminate the remaining microorganisms after chemomechanical preparation. The purpose of this article is to review the antimicrobial properties of Ca(OH)2 as an intracanal medicament in root canal treatment. The first part of this review details the characteristics of Ca(OH)2 and summarizes the results of in vitro studies related to its antimicrobial effect. The antimicrobial effect of Ca(OH)2 results from the release of hydroxyl ions when it comes into contact with aqueous fluids. Ca(OH)2 has a wide range of antimicrobial effects against common endodontic pathogens, but is less effective against Enterococcus faecalis and Candida albicans. The addition of vehicles or other agents might contribute to the antimicrobial effect of Ca(OH)2. PMID:25383341

  16. A titration model for evaluating calcium hydroxide removal techniques

    PubMed Central

    PHILLIPS, Mark; McCLANAHAN, Scott; BOWLES, Walter

    2015-01-01

    Objective Calcium hydroxide (Ca(OH)2) has been used in endodontics as an intracanal medicament due to its antimicrobial effects and its ability to inactivate bacterial endotoxin. The inability to totally remove this intracanal medicament from the root canal system, however, may interfere with the setting of eugenol-based sealers or inhibit bonding of resin to dentin, thus presenting clinical challenges with endodontic treatment. This study used a chemical titration method to measure residual Ca(OH)2 left after different endodontic irrigation methods. Material and Methods Eighty-six human canine roots were prepared for obturation. Thirty teeth were filled with known but different amounts of Ca(OH)2 for 7 days, which were dissolved out and titrated to quantitate the residual Ca(OH)2 recovered from each root to produce a standard curve. Forty-eight of the remaining teeth were filled with equal amounts of Ca(OH)2 followed by gross Ca(OH)2 removal using hand files and randomized treatment of either: 1) Syringe irrigation; 2) Syringe irrigation with use of an apical file; 3) Syringe irrigation with added 30 s of passive ultrasonic irrigation (PUI), or 4) Syringe irrigation with apical file and PUI (n=12/group). Residual Ca(OH)2 was dissolved with glycerin and titrated to measure residual Ca(OH)2 left in the root. Results No method completely removed all residual Ca(OH)2. The addition of 30 s PUI with or without apical file use removed Ca(OH)2 significantly better than irrigation alone. Conclusions This technique allowed quantification of residual Ca(OH)2. The use of PUI (with or without apical file) resulted in significantly lower Ca(OH)2 residue compared to irrigation alone. PMID:25760272

  17. Measurement of shift in K X-ray peak energies of potassium and calcium in different compounds using EDXRF

    NASA Astrophysics Data System (ADS)

    Kaur, Kamaldip; Mittal, Raj

    2014-12-01

    Energy shifts in K X-ray peaks of potassium and calcium in different chemical compounds have been determined from their X-ray spectra recorded in an energy dispersive X-ray fluorescence (EDXRF) set-up. The set-up comprises low-power X-ray tube photon source and Si(PIN) detector (AMPTEK model XR-100 CR). A statistical procedure has been followed to determine the shifts and t-test was applied to find the statistical significance of the results. The shifts were determined in potassium compounds; KCl, KBr, KI, K2CO3, K2Cr2O7, K2CrO4, K2SO4, K3Fe(CN)6, K4Fe(CN)6, KHSO4, KMnO4 and KSCN with KNO3 as reference and in calcium compounds; Ca(NO3)2 · 4H2O, Ca(OH)2, CaCl2, CaCO3, CaSO3 and CaSO4 · 2H2O with CaO as reference and correlated with differences in electro-negativity, number of ligands, structural changes, type of bonding, axial distances, etc. in the compounds. The shifts in potassium compounds have been evaluated for the first time while the same for calcium compounds almost agree well with the earlier reported measurements in literature.

  18. Synthesis, crystal structure refinement, and nonlinear-optical properties of CaB3O5(OH): Comparative crystal chemistry of calcium triborates

    NASA Astrophysics Data System (ADS)

    Yamnova, N. A.; Aksenov, S. M.; Stefanovich, S. Yu.; Volkov, A. S.; Dimitrova, O. V.

    2015-09-01

    Calcium triborate CaB3O5(OH) obtained by hydrothermal synthesis in the Ca(OH)2-H3BO3-Na2CO3-KCl system is studied by single-crystal X-ray diffraction. The parameters of the orthorhombic unit cell are as follows: a = 13.490(1), b = 6.9576(3), and c = 4.3930(2) Å; V = 412.32(3) Å3 and space group Pna21. The structure is refined in the anisotropic approximation of the atomic displacement parameters to R = 4.28% using 972 | F| > 4?( F). It is confirmed that the crystal structure of Ca triborate CaB3O5(OH) is identical to that described earlier. The hydrogen atom is localized. An SHG signal stronger than that of the quartz standard is registered. The phase transition of calcium triborate into calciborite is found on heating. The comparative crystal-chemical analysis of a series of borates with the general chemical formula 2Ca? · 3?2?3 · nH2? ( n = 0-13) with the constant Ca?: ?2?3= 2: 3 ratio and variable content of water is performed.

  19. EFFECT OF LASER LIGHT ON MATTER. LASER PLASMAS: Effects of CO2 laser radiation on large orthophosphoric acid and water drops and on spherical ice crystals

    NASA Astrophysics Data System (ADS)

    Rudash, V. K.

    1994-02-01

    An experimental investigation is reported of the conditions present during evaporation of suspended orthophosphoric acid and water drops, and of spherical ice crystals with a radius of the order of 1 mm when the laser radiation power density was 20-104 W cm-2 at the wavelength of 10.6 ?m. The lower limit of explosive evaporation was determined for H3PO4 drops and ice crystals. Only one evaporation mechanism of H3PO4 drops was observed (this mechanism was explosive), but there were two mechanisms in the case of water drops (convective with vapour ejection and explosive) and spherical ice crystals (melting followed by evaporation of a water drop and explosive evaporation). Repeated explosions of H2O drops were observed for a power density w = 104 W cm-2 when the beam diameter was 10 mm.

  20. Utilization of crude karanj (Pongamia pinnata) oil as a potential feedstock for the synthesis of fatty acid methyl esters.

    PubMed

    Khayoon, M S; Olutoye, M A; Hameed, B H

    2012-05-01

    Methyl esters were synthesized from crude karanj oil (CKO) by single step esterification with methanol using sulfuric acid (H(2)SO(4)) and phosphoric acid (H(3)PO(4)) as catalysts in a homogeneous batch process. H(3)PO(4) was less active than H(2)SO(4) during the process as it presented very low ester yields (<20%) for the various molar ratios of fatty acid to alcohol studied. With H(2)SO(4) as catalyst, the yield was as high as 89.8% at 65°C after 5h. The fatty acids profile of the oil (palmitic acid: ? 12%; stearic acid: ? 8%; oleic acid: ? 52% and linolenic acid of 17%) and the different reactivities of the acids were responsible for the observed differences in conversion to methyl esters. The findings attained with this study might contribute to the economic utilization of a non-edible feedstock. PMID:22405756

  1. Variation of nanopore diameter along porous anodic alumina channels by multi-step anodization.

    PubMed

    Lee, Kwang Hong; Lim, Xin Yuan; Wai, Kah Wing; Romanato, Filippo; Wong, Chee Cheong

    2011-02-01

    In order to form tapered nanocapillaries, we investigated a method to vary the nanopore diameter along the porous anodic alumina (PAA) channels using multi-step anodization. By anodizing the aluminum in either single acid (H3PO4) or multi-acid (H2SO4, oxalic acid and H3PO4) with increasing or decreasing voltage, the diameter of the nanopore along the PAA channel can be varied systematically corresponding to the applied voltages. The pore size along the channel can be enlarged or shrunken in the range of 20 nm to 200 nm. Structural engineering of the template along the film growth direction can be achieved by deliberately designing a suitable voltage and electrolyte together with anodization time. PMID:21456152

  2. Polybenzimidazole membranes for direct methanol fuel cell: Acid-doped or alkali-doped?

    NASA Astrophysics Data System (ADS)

    Li, Long-Yun; Yu, Bor-Chern; Shih, Chao-Ming; Lue, Shingjiang Jessie

    2015-08-01

    Polybenzimidazole (PBI) films immersed in 2 M phosphoric acid (H3PO4) or 6 M potassium hydroxide (KOH) solution form electrolytes for conducting proton or hydroxide, respectively. A direct methanol fuel cell (DMFC) with the alkali-KOH doped PBI gives 117.9 mW cm-2 of power output which is more than 2 times greater than the power density of 46.5 mW cm-2 with the H3PO4-doped PBI (vs.) when both of the DMFCs use a micro porous layer (MPL) in a gas-fed cathode and a MPL-free anode and are operated at 90 °C. When the MPL-free anode and cathode are used and the fuel flow rate is tripled, the peak power density of alkaline DMFC reaches 158.9 mW cm-2.

  3. Laser Fired Local Back Contact C-Si Solar Cells Using Phosphoric Acid for Back Surface Field

    NASA Astrophysics Data System (ADS)

    Balaji, Nagarajan; Park, Cheolmin; Ju, Minkyu; Lee, Seunghwan; Kim, Jungmo; Chung, Sungyoun; Raja, Jayapal; Yi, Junsin

    2015-04-01

    We report on a laser doping process for the formation of a local back surface field (BSF) using phosphoric acid (H3PO4) for n-type passivated emitter rear totally diffused silicon solar cells. The sheet resistance of the BSF layer was varied by changing the H3PO4 concentration. The BSF layer was passivated using SiN x . With the passivated BSF, the LBC solar cell shows an improved open circuit voltage. A laser power of 44 mW with 10 kHz resulted in a 45-?/sq BSF layer with effective lifetime of 290 ?s and a higher V oc of 623 mV. With the optimized laser parameters, devices with the best electrical results yielded a short circuit current density of 36 mA/cm2 and an efficiency of 18.26%.

  4. Scandium separation from tungsten crucibles : preliminary investigation into the separation of scandium metal from tungsten metal crucibles using an acid soak process.

    SciTech Connect

    Boyle, Timothy J.; Hess, Ryan Falcone; Neville, Michael Luke; Howard, Panit Clifton

    2013-02-01

    The first step in an attempt to isolate Sco from a Wo crucible was explored by soaking the samples in a series of organic (HOAc) and inorganic (HCl, H2SO4, H3PO4, HNO3) acids. All samples, except the HOAc, yielded a powder. The weight loss suggests that HNO3 is the most efficient solvent; however, the powders were tentatively identified by PXRD and found to contain both W and Sc by-products. The higher weight loss may also indicate dissolution of the Wo crucible, which was further evidenced upon visual inspection of the crucible. The H3PO4 acid soak yielded the cleanest removal of Sc from the crucible. More work to understand the separation of the Sco from the Wo crucible is necessary but the acid routes appear to hold promise under not as of yet established criteria.

  5. Monetite (CaHPO4) Synthesis in Ethanol at Room Temperature A. Cuneyt Tas*,w

    E-print Network

    Tas, A. Cuneyt

    were synthesized in ethanol (ethyl alcohol) solutions containing small aliquots of concentrated H3PO4.e., 142 mM Na1 , 5 mM K1 , and 50 mM Ca21 in water) for 6 days at 371C. I. Introduction MONETITE (CaHPO4 103.821, and g 5 88.331,9,10 with a calculated density of 2.92 g/cm3 . Its triclinic

  6. Residual arsenic site in oxidized AlxGa1xAs ,,x0.96... S.-K. Cheong,a)

    E-print Network

    are not intentionally doped. After selectively removing the GaAs cap layer in a 4:1 citric acid:H2O2 etch, a 1 cm 4 cm and the substrate is chemically removed. A phosphoric-acid­hydrogen-peroxide etch 4:1:50 H3PO4:H2O2:H2O is used to thin the substrate, the remainder of which is then removed by the slower, oxide-selective 4:1 citric

  7. Synthesis of (+)-Ipalbidine Based on 6-exo-trig Radical Cyclization of a ?-Amino Radical.

    PubMed

    Chea, JongMyoung; Clive, Derrick L J

    2015-10-16

    N-Boc (S)-proline was converted into (2S)-2-[(phenylselanyl)methyl]pyrrolidine, which was alkylated on nitrogen with 2-bromo-1-(4-methoxyphenyl)ethan-1-one. Reaction with vinyllithium, 6-exo-trig radical cyclization (Bu3SnH, AIBN, PhMe, 110 °C), dehydration (P2O5, H3PO4), and demethylation (BBr3) gave (+)-ipalbidine with ee >99%. PMID:26402510

  8. Preliminary surface analysis of etched, bleached, and normal bovine enamel

    SciTech Connect

    Ruse, N.D.; Smith, D.C.; Torneck, C.D.; Titley, K.C. )

    1990-09-01

    X-ray photoelectron spectroscopic (XPS) and secondary ion-mass spectroscopic (SIMS) analyses were performed on unground un-pumiced, unground pumiced, and ground labial enamel surfaces of young bovine incisors exposed to four different treatments: (1) immersion in 35% H2O2 for 60 min; (2) immersion in 37% H3PO4 for 60 s; (3) immersion in 35% H2O2 for 60 min, in distilled water for two min, and in 37% H3PO4 for 60 s; (4) immersion in 37% H3PO4 for 60 s, in distilled water for two min, and in 35% H2O2 for 60 min. Untreated unground un-pumiced, unground pumiced, and ground enamel surfaces, as well as synthetic hydroxyapatite surfaces, served as controls for intra-tooth evaluations of the effects of different treatments. The analyses indicated that exposure to 35% H2O2 alone, besides increasing the nitrogen content, produced no other significant change in the elemental composition of any of the enamel surfaces investigated. Exposure to 37% H3PO4, however, produced a marked decrease in calcium (Ca) and phosphorus (P) concentrations and an increase in carbon (C) and nitrogen (N) concentrations in unground un-pumiced specimens only, and a decrease in C concentration in ground specimens. These results suggest that the reported decrease in the adhesive bond strength of resin to 35% H2O2-treated enamel is not caused by a change in the elemental composition of treated enamel surfaces. They also suggest that an organic-rich layer, unaffected by acid-etching, may be present on the unground un-pumiced surface of young bovine incisors. This layer can be removed by thorough pumicing or by grinding. An awareness of its presence is important when young bovine teeth are used in a model system for evaluation of resin adhesiveness.

  9. A microleakage study of gutta-percha/AH Plus and Resilon/Real self-etch systems after different irrigation protocols

    PubMed Central

    PRADO, Maíra; SIMÃO, Renata Antoun; GOMES, Brenda Paula Figueiredo de Almeida

    2014-01-01

    The development and maintenance of the sealing of the root canal system is the key to the success of root canal treatment. The resin-based adhesive material has the potential to reduce the microleakage of the root canal because of its adhesive properties and penetration into dentinal walls. Moreover, the irrigation protocols may have an influence on the adhesiveness of resin-based sealers to root dentin. Objective The objective of the present study was to evaluate the effect of different irrigant protocols on coronal bacterial microleakage of gutta-percha/AH Plus and Resilon/Real Seal Self-etch systems. Material and Methods One hundred ninety pre-molars were used. The teeth were divided into 18 experimental groups according to the irrigation protocols and filling materials used. The protocols used were: distilled water; sodium hypochlorite (NaOCl)+eDTA; NaOCl+H3PO4; NaOCl+eDTA+chlorhexidine (CHX); NaOCl+H3PO4+CHX; CHX+eDTA; CHX+ H3PO4; CHX+eDTA+CHX and CHX+H3PO4+CHX. Gutta-percha/AH Plus or Resilon/Real Seal Se were used as root-filling materials. The coronal microleakage was evaluated for 90 days against Enterococcus faecalis. Data were statistically analyzed using Kaplan-Meier survival test, Kruskal-Wallis and Mann-Whitney tests. Results No significant difference was verified in the groups using chlorhexidine or sodium hypochlorite during the chemo-mechanical preparation followed by eDTA or phosphoric acid for smear layer removal. The same results were found for filling materials. However, the statistical analyses revealed that a final flush with 2% chlorhexidine reduced significantly the coronal microleakage. Conclusion A final flush with 2% chlorhexidine after smear layer removal reduces coronal microleakage of teeth filled with gutta-percha/AH Plus or Resilon/Real Seal SE. PMID:25025557

  10. Determination of Aqueous Inorganic Carbon and Calculated Carbonate Alkalinity of Fresh/Estuarine/Coastal Waters.

    E-print Network

    Boynton, Walter R.

    analysis where the sample is injected into a receptacle of phosphoric acid. The carbonates are reduced to proceed. 2.2 An aliquot of sample is injected into a receptacle of 25% v/v phosphoric acid (H3PO4 of salinity. 1.2 A Method Detection Limit (MDL) of 0.17 mg/L TIC was determined using the Student's t value (3

  11. ECLSS Sustaining Compatibility Testing on Urine Processor Assembly Nonmetallic Materials for Reformulation of Pretreated Urine Solution

    NASA Technical Reports Server (NTRS)

    Wingard, C. D.

    2015-01-01

    On International Space Station (ISS), the Urine Processor Assembly (UPA) converts human urine and flush water into potable water. The urine is acid-pretreated primarily to control microbial growth. In recent years, the sulfuric acid (H2SO4) pretreatment was believed to be largely responsible for producing salt crystals capable of plugging filters in UPA components and significantly reducing the percentage of water recovery from urine. In 2012, ISS management decided to change the acid pretreatment for urine from sulfuric to phosphoric with the goal of eliminating or minimizing formation of salt crystals. In 2013-2014, as part of the qualification of the phosphoric acid (H3PO4) formulation, samples of 12 nonmetallic materials used in UPA components were immersed for up to one year in pretreated urine and brine solutions made with the new H3PO4 formulation. Dynamic mechanical analysis (DMA) was used to measure modulus (stiffness) of the immersed samples compared to virgin control samples. Such compatibility data obtained by DMA for the H3PO4-based solutions were compared to DMA data obtained for the H2SO4-based solutions in 2002-2003.

  12. Structural characterization of some sol-gel derived phosphosilicate glasses

    NASA Astrophysics Data System (ADS)

    Todan, L.; Anghel, E. M.; Osiceanu, P.; Turcu, R. V. F.; Atkinson, I.; Simon, S.; Zaharescu, M.

    2015-04-01

    A comparative study of three phosphosilicate gels of the 90SiO2-10P2O5 composition obtained from tetraethoxysilane and three phosphorous precursors: triethylphosphate (TEP), triethylphosphite (TEPI) and H3PO4 is performed. 29Si and 31P Magic Angle Spining NMR, X-ray Photoelectron, X-ray Fluorescence and Raman spectroscopies as well as TG analysis are used in order to establish phosphorous precursors and annealing influence on composition and structure of the outcome materials. Unlike the three dimensional silicate network made of Si(OSi)x(OH)4-x species, unreacted TEP (100% Q1 condensed phosphorous units) from TEP derived gel and a large amount of isolated phosphorous species (39.7% Q0) in the H3PO4 derived gel are identified. Annealing at 700 °C of the three gels give similar structure with the 90SiO2-10P2O5 glass, excepting the triethylphosphate derived glass that has a much lower P content. Thus, the H3PO4 derived glass at 700 and 1000 °C shows 1.89 and 1.94 times higher P2O5/SiO2 ratios than in the case of the TEP derived one.

  13. Exposure damage mechanisms for KCl windows in high power laser systems

    NASA Technical Reports Server (NTRS)

    Blaszuk, P. R.; Woody, B. A.; Hulse, C. O.; Davis, J. W.; Waters, J. P.

    1976-01-01

    An experimental study of the 10.6 micrometer and 0.6328 micrometer optical properties of single crystal and europium doped polycrystal is described. Significant variations in the optical properties are observed over periods of exposure up to 100 hours. Models are proposed to predict the 10.6 micrometer absorptivity for long exposure periods. Mechanical creep has been detected in both materials at high temperature.

  14. Selective Reduction of Active Metal Chlorides from Molten LiCl-KCl using Lithium Drawdown

    SciTech Connect

    Michael F. Simpson; Daniel LaBrier; Michael Lineberry; Tae-Sic Yoo

    2012-10-01

    In support of optimizing electrorefining technology for treating spent nuclear fuel, lithium drawdown has been investigated for separating actinides from molten salt electrolyte. Drawdown reaction selectivity is a major issue that needs to be investigated, since the goal is to remove actinides while leaving the fission products in the salt. A series of lithium drawdown tests with surrogate fission product chlorides was run to obtain selectivity data with non-radioactive salts, develop a predictive model, and draw conclusions about the viability of using this process with actinide-loadd salt. Results of tests with CsCl, LaCl3, CeCl3, and NdCl3 are reported here. An equilibrium model has been formulated and fit to the experimental data. Excellent fits to the data were achieved. Based on analysis and results obtained to date, it is concluded that clean separation between minor actinides and lanthanides will be difficult to achieve using lithium drawdown.

  15. Time-resolved picosecond spectroscopy of the resonant secondary radiation of F centers in KCl

    NASA Astrophysics Data System (ADS)

    Akiyama, N.; Nakahara, F.; Ohkura, H.

    1995-12-01

    The linear polarization (P HL) of hot luminescence (HL) composing of the resonant secondary radiation of the F centers has been measured using a time-resolved picosecond spectroscopy over the whole Stokes wavenumber ? range. The P HL holds constant value of about 40% until the onset of ordinary luminescence (OL), from where it decreases to vanishingly small with decrease of ? This implies that the optically excited F center relaxes down along the 2p-like adiabatic potential energy surface (APES) trough, and transits to the 2s-like APES trough to form the relaxed excited state (RES). The lattice relaxation time and the dynamical transition time are ultra fast estimated to be less than 15 psec.

  16. Materials Data on KClO3 (SG:11) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  17. Materials Data on KClO4 (SG:62) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  18. Anodic dissolution of irradiated metallic fuels in LiCl-KCl melt

    NASA Astrophysics Data System (ADS)

    Murakami, T.; Kato, T.; Rodrigues, A.; Ougier, M.; Iizuka, M.; Koyama, T.; Glatz, J.-P.

    2014-09-01

    Electrorefining is the main step in pyro-process of spent nuclear fuels, where actinides are recovered and separated from fission products. In the present study, electrorefining of irradiated metallic fuels called METAPHIX-1 (U-19 wt%Pu-10 wt%Zr alloy irradiated at PHENIX reactor, approximate maximum burn-up 2.5 at%) was performed. A major focus was on minimization of Zr co-dissolution from spent metallic fuels to reduce the burden to the pyro-process. Based on the ICP-MS analysis results and the SEM-EDX observations, the anodic dissolution behavior of the irradiated metallic fuels and the mass balances of actinides and fission products during the electrorefining were evaluated.

  19. MIGRATION OF GAS-LIQUID INCLUSIONS IN KCl AND NaCl SINGLE CRYSTALS

    SciTech Connect

    Olander, Donald R.; Machiels, Albert J.; Muchowski, Eugen

    1980-08-01

    Natural salt deposits contain small brine inclusions which can be set into motion by a temperature gradient arising from storage of nuclear wastes in the salt. Inclusions totally filled with liquid move up the temperature gradient, but cavities which are filled partly with liquid and partly by an insoluble gas move in the opposite direction. The velocities of these gas-liquid inclusions are calculated from a model which includes: heat transport in the gas/liquid/solid composite medium; vapor transport of water in the gas bubble as the principal mechanism causing cavity motion; and the effect of molecular and thermal diffusion on transport of salt in the liquid phase. An analytical expression for the inclusion velocity is obtainable with certain simplifications, which include: approximating the cubical cavity in the solid as a spherical hole containing a central gas bubble and an annular shell of liquid; neglecting interface kinetics (i.e., slow dissolution and crystallization steps) and assuming the process to be diffusion-controlled and disregarding fluid motion generated by surface tension gradients at the gas/liquid interface. The theory predicts a change in the migration direction at a critical volume fraction gas in the cavity. For gas fractions greater than this critical value, the theory gives the velocities of migration down the temperature gradient which are in satisfactory agreement with available experimental data.

  20. In vitro evaluation of the antimicrobial activity of calcium hydroxide combined with chlorhexidine gel used as intracanal medicament.

    PubMed

    Gomes, Brenda Paula Figueiredo de Almeida; Vianna, Morgana Eli; Sena, Neylla Teixeira; Zaia, Alexandre Augusto; Ferraz, Caio Cezar Randi; de Souza Filho, Francisco José

    2006-10-01

    The aim of this study was to investigate the antimicrobial activity of calcium hydroxide (Ca(OH)2) combined with 2% chlorhexidine gluconate (CHX) gel against endodontic pathogens and to compare the results with the ones achieved by Ca(OH)2 mixed with sterile water and by CHX gel alone. Two methods were used: the agar diffusion test and the direct contact test. Ca(OH)2 + 2% CHX gel produced inhibitory zones ranging from 2.84 to 6.5 mm, and required from 30 seconds to 6 hours to eliminate all tested microorganisms. However, 2% CHX gel showed the largest microbial growth zones from 4.33 to 21.67 mm, and required 1 minute or less to inhibit all tested microorganisms. A paste of Ca(OH)2 plus sterile water inhibited only the microorganisms with which it was in direct contact and required from 30 seconds to 24 hours to kill all tested microorganisms. In conclusion, 2% CHX gel + Ca(OH)2 showed better antimicrobial activity than Ca(OH)2 manipulated with sterile water. PMID:16997123

  1. Effect of the addition of calcium hydroxide on the hydrothermal-mechanochemical treatment of Eucalyptus.

    PubMed

    Ishiguro, Maki; Endo, Takashi

    2015-02-01

    The effect of Ca(OH)2 addition on optimization of hydrothermal-mechanochemical pretreatment, which combines hydrothermal and milling treatments, was examined. The highest glucose yield of 90% was achieved in the ball-milled specimen previously treated at 170°C in the presence of 20% Ca(OH)2 per substrate weight. The specific surface area of the substrate was closely correlated with glucose yield, and a larger specific surface area was obtained when treating the specimen at 170°C in the presence of Ca(OH)2 compared to treatment at 170°C without Ca(OH)2. Although the Ca(OH)2-treated specimen was relatively unaffected by delignification, the cleavage of the ester bonds between lignin and hemicellulose was confirmed by FT-IR. This suggests that Ca(OH)2 weakens the substrate structure by loosening the bonds between lignin and hemicellulose as the mechanism to increase the specific surface area regardless of the high lignin content, facilitating the fibrillation of fibers with mechanical milling. PMID:25496951

  2. Electrochemical behaviors of the magnesium alloy substrates in various pretreatment solutions

    NASA Astrophysics Data System (ADS)

    Zhu, Yanping; Yu, Gang; Hu, Bonian; Lei, Xiping; Yi, Haibo; Zhang, Jun

    2010-02-01

    Interface reactions and film features of AZ91D magnesium alloy in pickling, activation and zinc immersion solutions have been investigated. The surface morphologies of the specimens were observed with scanning electron microscope (SEM). Electrochemical behaviors of AZ91D magnesium alloy in the baths of pickling, activation and zinc immersion were analyzed based on the open circuit potential (OCP) - time curves in various solutions. The results show that the corrosive rate in HNO 3 + CrO 3 or HNO 3 + H 3PO 4 pickling solution was more rapid than in KMnO 4 pickling-activation solution. Both ? phase and ? phase of the substrates were uniformly corroded in HNO 3 + CrO 3 or HNO 3 + H 3PO 4 pickling solution, the coarse surface can augment the mechanical occlusive force between the subsequent coatings and the substrates, so coatings with good adhesion can be obtained. In HF activation solution, the chromic compound formed via HNO 3 + CrO 3 pickling was removed and a compact MgF 2 film was formed on the substrate surface. In K 4P 2O 7 activation solution, the corrosion products formed via HNO 3 + H 3PO 4 pickling were removed, a new thin film of oxides and hydroxides was formed on the substrate surface. In KMnO 4 pickling-activation solution, a film of manganic oxides and phosphates was adhered on the substrate surface. Zinc film was symmetrically produced via K 4P 2O 7 activation or KMnO 4 pickling-activation, so it was good interlayer for Ni or Cu electroplating. Asymmetrical zinc film was produced because the MgF 2 film obtained in the HF activation solution had strong adhesive attraction and it was not suitable for interlayer for electroplating. However, the substrate containing compact MgF 2 film without zinc immersion was fit for direct electroless Ni-P plating.

  3. Unblocking the Sink: Improved CID-Based Analysis of Phosphorylated Peptides by Enzymatic Removal of the Basic C-Terminal Residue

    NASA Astrophysics Data System (ADS)

    Lanucara, Francesco; Chi Hoo Lee, Dave; Eyers, Claire E.

    2013-12-01

    A one-step enzymatic reaction for improving the collision-induced dissociation (CID)-based tandem mass spectrometry (MS/MS) analysis of phosphorylated peptides in an ion trap is presented. Carboxypeptidase-B (CBP-B) was used to selectively remove C-terminal arginine or lysine residues from phosphorylated tryptic/Lys-C peptides prior to their MS/MS analysis by CID with a Paul-type ion trap. Removal of this basic C-terminal residue served to limit the extent of gas-phase neutral loss of phosphoric acid (H3PO4), favoring the formation of diagnostic b and y ions as determined by an increase in both the number and relative intensities of the sequence-specific product ions. Such differential fragmentation is particularly valuable when the H3PO4 elimination is so predominant that localizing the phosphorylation site on the peptide sequence is hindered. Improvement in the quality of tandem mass spectral data generated by CID upon CBP-B treatment resulted in greater confidence both in assignment of the phosphopeptide primary sequence and for pinpointing the site of phosphorylation. Higher Mascot ion scores were also generated, combined with lower expectation values and higher delta scores for improved confidence in site assignment; Ascore values also improved. These results are rationalized in accordance with the accepted mechanisms for the elimination of H3PO4 upon low energy CID and insights into the factors dictating the observed dissociation pathways are presented. We anticipate this approach will be of utility in the MS analysis of phosphorylated peptides, especially when alternative electron-driven fragmentation techniques are not available.

  4. Effects of acids used in the microabrasion technique: Microhardness and confocal microscopy analysis

    PubMed Central

    Pini, Núbia-Inocencya-Pavesi; Ambrosano, Gláucia-Maria-Bovi; da Silva, Wander-José; Aguiar, Flávio-Henrique-Baggio; Lovadino, José-Roberto

    2015-01-01

    Background This study evaluated the effects of the acids used in the microabrasion on enamel. Material and Methods Seventy enamel/dentine blocks (25 mm2) of bovine incisors were divided into 7 groups (n=10). Experimental groups were treated by active/passive application of 35% H3PO4 (E1/E2) or 6.6% HCl (E3/E4). Control groups were treated by microabrasion with H3PO4+pumice (C5), HCl+silica (C6), or no treatment (C7). The superficial (SMH) and cross-sectional (CSMH; depths of 10, 25, 50, and 75 µm) microhardness of enamel were analyzed. Morphology was evaluated by confocal laser-scanning microscopy (CLSM). Data were analyzed by analysis of variance (Proc Mixed), Tukey, and Dunnet tests (?=5%). Results Active application (E1 and E3) resulted in higher microhardness than passive application (E2 and E4), with no difference between acids. For most groups, the CSMH decreased as the depth increased. All experimental groups and negative controls (C5 and C6) showed significantly reduced CSMH values compared to the control. A significantly higher mean CSMH result was obtained with the active application of H3PO4 (E1) compared to HCl (E3). Passive application did not result in CSMH differences between acids. CLSM revealed the conditioning pattern for each group. Conclusions Although the acids displayed an erosive action, use of microabrasive mixture led to less damage to the enamel layers. Key words:Enamel microabrasion, enamel microhardness, confocal laser scanning microscopy. PMID:26535098

  5. HISTORIC LIST OF MAPLETHORPE FELLOWS FROM OCTOBER 1987 Derek Anthony John Balon (KCL) October 1987 -September 1990

    E-print Network

    Applebaum, David

    system to study drug transport and metabolism." Philip Charles Gordge (Sch Pharm) April 1992 - October.F. Redox potential measurement in the gastrointestinal tract in man. In preparation. Summary of Work

  6. Schedule for Completion of NUS B.Sc. (Hons.) in Chemistry KCL M.Sc. in Analytical Toxicology

    E-print Network

    Yao, Shao Q

    MSc Modules {ECTS}Chemistry Major Other graduation requirements YEAR1 Semesters1&2 CM1111 Inorganic Semesters1&2 CM2101 Physical Chemistry 2[4] CM2111 Inorganic Chemistry 2 [4] CM2121 Organic Chemistry 2 [4 in Chemistry 3 [4] YEAR3 Semesters1&2 CM3291 Advanced Experiments in Inorganic and Organic Chemistry CM3292

  7. Thermodynamics and mechanisms of glycine solvation in aqueous NaCl and KCl solutions at 298.15 K

    NASA Astrophysics Data System (ADS)

    Roy, S.; Hossain, A.; Mahali, K.; Dolui, B. K.

    2015-11-01

    In the present study the solubility of glycine in aqueous sodium chloride and potassium chloride solution was determined under different experimental conditions using `formol titrimetry' method. The thermodynamic parameters like standard transfer Gibbs energies and entropies have been evaluated at 298.15 K. Other important parameters like molar volume, densities, solvent diameter, etc., of the experimental solutions have also been determined in this study. The above mentioned parameters have been used to determine ? t,ch 0 ( i)i.e., chemical effects of the transfer Gibbs energies and T? t, ch 0 ( i)i.e., chemical effects of the transfer entropy. The solvation of glycine is influenced by different factors such as nature of the solute, interactions between solute and solvents, etc., which has been explained by different physical and analytical approach.

  8. [Effect of intravenous infusion of KCl on the electrocardiogram and serum potassium in dogs with normal renal function].

    PubMed

    Bravo-Zúñiga, Jessica; Huapaya, Julio; Valencia, Cesar; Bezada, Sandra; Leon, Cristian; Ferrandiz-Espadin, Renato; Cieza, Javier

    2015-01-01

    Variations in serum potassium (K+) and electrocardiographic changes at different infusion speeds of intravenous K+ were studied in dogs. Solutions of 20, 40, 60 and 80 mEq of K+ were infused in one hour to dogs with normal renal function and normal serum K+. Nine dogs were studied: three without prior hydration and six with previous hydration. Infusing 20 mEq/hour of K+ produced an increase in heart rate without changes in the electrocardiogram. With 40 mEq/hour there were changes in the "t" and "p" waves, and with 60 and 80 mEq/hour, alterations consistent with cardiac ischemia and ventricular tachycardia. Dogs without hydration had more obvious and fatal electrocardiographic changes. Doses of 20 mEq/hour of K + caused no morbidity or mortality in the animals studied. Higher doses showed various complications which depended on the hydration status of the animal, its urinary flow and potassium level. PMID:26102114

  9. Adsorption of PTCDA on Terraces and at Steps Sites of the KCl(100) A. Paulheim, and M. Sokolowski*

    E-print Network

    Schmidt, Wolf Gero

    are statistically distributed on the terraces with an azimuthal orientation of the long axis along the polar 110 bears similarity to PTCDA on the low index Ag surfaces,1 although the interfacial bonding

  10. Following the electroreduction of uranium dioxide to uranium in LiCl-KCl eutectic in situ using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Brown, L. D.; Abdulaziz, R.; Jervis, R.; Bharath, V. J.; Atwood, R. C.; Reinhard, C.; Connor, L. D.; Simons, S. J. R.; Inman, D.; Brett, D. J. L.; Shearing, P. R.

    2015-09-01

    The electrochemical reduction of uranium dioxide to metallic uranium has been investigated in lithium chloride-potassium chloride eutectic molten salt. Laboratory based electrochemical studies have been coupled with in situ energy dispersive X-ray diffraction, for the first time, to deduce the reduction pathway. No intermediate phases were identified using the X-ray diffraction before, during or after electroreduction to form ?-uranium. This suggests that the electrochemical reduction occurs via a single, 4-electron-step, process. The rate of formation of ?-uranium is seen to decrease during electrolysis and could be a result of a build-up of oxygen anions in the molten salt. Slow transport of O2- ions away from the UO2 working electrode could impede the electrochemical reduction.

  11. Natural-abundance 17O NMR spectra of some inorganic and biologically important phosphates

    NASA Astrophysics Data System (ADS)

    Gerothanassis, Ioannis P.; Sheppard, Norman

    A number of optimization techniques were employed to obtain 17O NMR spectra at natural abundance for a variety of inorganic and orgnic phosphates and polyphosphates. 17O chemical shifts and some JPO coupling constants are reported for the orthophosphate series of ions from H 3PO 4 to PO 43-, the pyrophosphate ion, P 2O 74-, the linear tripolyphosphate ion, P 3O 105-, and the cyclic trimetaphosphate ion, P 3O 93-; and for disodium DL-?-glycerophosphate and monosodium adenosine monophosphate. 17O- depleted water enables much improved results to be obtained in acqueous solutions.

  12. Simplex-optimized chromatographic resolution of selected ionic liquid cations utilizing a polar reversed-phase system.

    PubMed

    Nichthauser, Joanna; Paszkiewicz, Monika; Sk?adanowski, Andrzej C; Stepnowski, Piotr

    2008-10-01

    This study reports on optimization of the RP-HPLC separation of imidazolium and pyridinium ionic liquid cations using a variable-size simplex algorithm. Under the optimized conditions, all critical pairs of ionic liquids were successfully separated in a single chromatographic run. The mobile phase at the point corresponding to the optimum consisted of 10% MeOH and 90% 15 mM KH(2)PO(4)/H(3)PO(4) with pH 3.43. The coefficients of asymmetry for all of the compounds analyzed at the simplex algorithm optimum ranged from 0.83 to 2.91. PMID:18845900

  13. Molecular Emission and Temperature Measurements from Single-Bubble Sonoluminescence

    NASA Astrophysics Data System (ADS)

    Xu, Hangxun; Suslick, Kenneth S.

    2010-06-01

    Single-bubble sonoluminescence (SBSL) spectra in H2O show featureless continuum emission. From an acoustically driven, moving bubble in phosphoric acid (H3PO4), we observe very strong molecular emission from excited OH radicals (˜310nm), which can be used as a spectroscopic thermometer by fitting the experimental SBSL spectra to the OH A?+2-X?2 rovibronic transitions. The observed emission temperature (Tem) ranges from 6200 to 9500 K as the acoustic pressure (Pa) varies from 1.9 to 3.1 bar and from 6000 to >10000K as the dissolved monatomic gas varies over the series from He to Xe.

  14. Acetic Acid (H3COOH): GaAs; Pb; Ti Hydrochloric Acid (HCl): Al; Cr; Cu; Fe2O3; Ga; GaAs; GaN; In; Fe; Pb; Ni; NiO, Ni2O3; Sn;

    E-print Network

    Garmestani, Hamid

    ; Fe; Pb; Ni; NiO, Ni2O3; Sn; SnO2; Ti; Zn Hydrofluoric Acid (HF): GaAs; Ni; SiO2; Ti Nitric Acid (HNO3 : hydrofluoric acid (49%, aq) HNO3 : nitric acid (70%, aq) H2SO4 : sulfuric acid (96%, aq) H3PO4 : phosphoricAcetic Acid (H3COOH): GaAs; Pb; Ti Hydrochloric Acid (HCl): Al; Cr; Cu; Fe2O3; Ga; GaAs; GaN; In

  15. Chromonic liquid crystalline nematic phase exhibited in binary mixture of two liquid crystals

    NASA Astrophysics Data System (ADS)

    Govindaiah, T. N.; Sreepad, H. R.; Sridhar, K. N.; Sridhara, G. R.; Nagaraja, N.

    2015-06-01

    A binary mixture of abietic acid and orthophosphoric acid (H3PO4) exhibits co-existence of biphasic region of Nematic+Isotropic (N+I), lyotropic Nematic (ND) and Smectic-G (SmG) phases. The mixture exhibits N+I, N and SmG phases at different concentrations and at different temperatures. Mixtures with all concentrations of abietic acid exhibit I?N+I?N?SmG phases sequentially when the specimen is cooled from its isotropic melt. These phases have been characterized by using differential scanning calorimetric, X-ray diffraction, and optical texture studies.

  16. Facile template-free synthesis of pine needle-like Pd micro/nano-leaves and their associated electro-catalytic activities toward oxidation of formic acid

    PubMed Central

    2011-01-01

    Pine needle-like Pd micro/nano-leaves have been synthesized by a facile, template-free electrochemical method. As-synthesized Pd micro/nano-leaves were directly electrodeposited on an indium tin oxide substrate in the presence of 1.0 mM H2PdCl4 + 0.33 M H3PO4. The formation processes of Pd micro/nano-leaves were revealed by scanning electron microscope, and further characterized by X-ray diffraction and electrochemical analysis. Compared to conventional Pd nanoparticles, as-prepared Pd micro/nano-leaves exhibit superior electrocatalytic activities for the formic acid oxidation. PMID:21711919

  17. Defect selective etching of GaAsyP1-y photovoltaic materials

    NASA Astrophysics Data System (ADS)

    Yaung, Kevin Nay; Tomasulo, Stephanie; Lang, Jordan R.; Faucher, Joseph; Lee, Minjoo Larry

    2014-10-01

    Rapid and accurate threading dislocation density (TDD) characterization of direct-gap GaAsyP1-y photovoltaic materials using molten KOH defect selective etching (DSE) is demonstrated. TDDs measured using molten KOH DSE show close agreement with those from both electron beam-induced current mapping and planar view transmission electron microscopy, provided TDD<107 cm-2. H3PO4 DSE is also demonstrated as an accurate method for characterizing TDD of GaP substrates. Taken together, the DSE methods described here enable TDD characterization over large areas (>105 ?m2) from substrate to GaAsyP1-y device layer.

  18. Effect of dentin treatment on proliferation and differentiation of human dental pulp stem cells

    PubMed Central

    Park, Minjeong; Pang, Nan-Sim

    2015-01-01

    Objectives Sodium hypochlorite (NaOCl) is an excellent bactericidal agent, but it is detrimental to stem cell survival, whereas intracanal medicaments such as calcium hydroxide (Ca[OH]2) promote the survival and proliferation of stem cells. This study evaluated the effect of sequential NaOCl and Ca[OH]2 application on the attachment and differentiation of dental pulp stem cells (DPSCs). Materials and Methods DPSCs were obtained from human third molars. All dentin specimens were treated with 5.25% NaOCl for 30 min. DPSCs were seeded on the dentin specimens and processed with additional 1 mg/mL Ca[OH]2, 17% ethylenediaminetetraacetic acid (EDTA) treatment, file instrumentation, or a combination of these methods. After 7 day of culture, we examined DPSC morphology using scanning electron microscopy and determined the cell survival rate with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. We measured cell adhesion gene expression levels after 4 day of culture and odontogenic differentiation gene expression levels after 4 wk using quantitative real-time polymerase chain reaction. Results DPSCs did not attach to the dentin in the NaOCl-treated group. The gene expression levels of fibronectin-1 and secreted phosphoprotein-1 gene in both the Ca[OH]2- and the EDTA-treated groups were significantly higher than those in the other groups. All Ca[OH]2-treated groups showed higher expression levels of dentin matrix protein-1 than that of the control. The dentin sialophosphoprotein level was significantly higher in the groups treated with both Ca[OH]2 and EDTA. Conclusions The application of Ca[OH]2 and additional treatment such as EDTA or instrumentation promoted the attachment and differentiation of DPSCs after NaOCl treatment. PMID:26587415

  19. HCl dry removal with modified Ca-based sorbents at moderate to high temperatures

    NASA Astrophysics Data System (ADS)

    Chen, Dezhen; Wang, Xiongping; Zhu, Tong; Zhang, Hesheng

    2003-08-01

    Modified Ca-based sorbents were obtained by adding sodium alkali into Ca(OH)2 and CaCO3. Reactive properties of modified Ca-based sorbents with acidic gases were investigated through reacting with gaseous HCl at 450 760°C, and SEM and XRD technologies were adopted to get information on the reaction mechanism. Experimental data showed that HCl dry removal efficiencies increased with temperature before 700°C for all of the investigated sorbents, and there existed improved sorbents that corresponded to the highest removal efficiencies under the similar conditions. SEM photographs exhibited morphology difference between original and improved sorbents both before and after the reaction; and displayed that improved sorbents formed more porous product layers than original sorbents especially at higher temperature when product sintering became heavier, which is favorable to HCl dry removal. XRD analysis showed that (1) improved Ca(OH)2 and CaCO3 were less crystalline than original lime and limestone; (2) the reaction product species of improved Ca(OH)2 changed with reaction temperature, while for original Ca(OH)2 the same product species appeared for all of the tested temperatures; and (3) for improved CaCO3, the only product at lower temperatures was CaCl2.2H2O and more product species were produced when temperature was higher than 650°C, but no CaCl2.Ca(OH)2.H2O formed at 700°C, while for the case of original CaCO3, the undesired CaCl2.Ca(OH)2.H2O appeared at 700°C. Presently, reaction temperature interval of 650 700°C is recommended for improved Ca(OH)2 to get the highest efficiency, for improved CaCO3 reaction at higher temperature deserves further investigation to make a good choice.

  20. Effect of phosphoric acid pretreatment of corncobs on the fermentability of Clostridium beijerinckii TISTR 1461 for biobutanol production.

    PubMed

    Boonsombuti, Akarin; Luengnaruemitchai, Apanee; Wongkasemjit, Sujitra

    2015-01-01

    Corncobs pretreated with H2SO4, HNO3, and H3PO4 were compared to evaluate the fermentation ability of Clostridium beijerinckii TISTR 1461 to produce biobutanol via acetone-butanol-ethanol (ABE) fermentation. It was found that the hydrolysate from H3PO4 pretreatment could be used as a substrate without any inhibitor removal methods. However, in terms of sugar yield, it gave the lowest total sugars in both pretreatment and enzymatic hydrolysis. Response surface methodology was applied to optimize enzymatic hydrolysis of the pretreated corncobs. The optimized conditions reduced the consumption of enzymes and hydrolysis time to 7.68 FPU/g biomass and 63.88 hr, respectively, and yielded 51.82 g/L reducing sugars. The Celluclast 1.5 L and Novozyme 188 enzyme ratio were varied to maximize the hydrolyzed sugars. The ABE fermentation, using substrate from phosphoric acid pretreatment of corncobs, with 10 g/L glucose supplementation produced 11.64 g/L of total ABE, which was close to the control experiment using synthetic medium. This study showed that corncobs pretreated with phosphoric acid could potentially be used as a substrate without using a detoxification process. PMID:24678653

  1. A polytetrafluoroethylene porous membrane and dimethylhexadecylamine quaternized poly (vinyl benzyl chloride) composite membrane for intermediate temperature fuel cells

    NASA Astrophysics Data System (ADS)

    Cao, Yuan-Cheng; Xu, Chenxi; Zou, Linling; Scott, Keith; Liu, Jiyan

    2015-10-01

    A composite material for phosphoric acid (PA) loaded membrane was prepared using a porous polytetrafluoroethylene (PTFE) thin film. N, N-Dimethylhexadecylamine partially quaternized poly (vinyl benzyl chloride) (qPVBzCl-) was synthesized as the substrate for the phosphoric acid loaded polymer membrane. SEM observation indicated that the pores were filled with the qPVBzCl-. The maximum PA loading level was calculated to be 4.67-5.12 per repeat unit on average. TGA results showed that resultant composite membrane was stable in the intermediate temperature from 100 °C to 200 °C. The composite membrane tensile stress was 56.23 MPa, and the Young's Modulus was 0.25 GPa, and the fractured elongation was 23%. The conductivity of the composite membrane after the PA addition (H3PO4@PTFE/qPVBzCl-) increased from 0.085 S cm-1 to 0.11 S cm-1 from 105 °C to 180 °C. The peak power density of the H2/O2 at 175 °C under low humidity condition (<1%) for H3PO4@PTFE/qPVBzCl- membranes was 360 mW cm-2.

  2. A boron phosphate-phosphoric acid composite membrane for medium temperature proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Mamlouk, M.; Scott, K.

    2015-07-01

    A composite membrane based on a non-stoichiometric composition of BPO4 with excess of PO4 (BPOx) was synthesised and characterised for medium temperature fuel cell use (120-180 °C). The electrolyte was characterised by FTIR, SS-NMR, TGA and XRD and showed that the B-O is tetrahedral, in agreement with reports in the literature that boron phosphorus oxide compounds at B:P < 1 are exclusively built of borate and phosphate tetrahedra. Platinum micro electrodes were used to study the electrolyte compatibility and stability towards oxygen reduction at 150 °C and to obtain kinetic and mass transport parameters. The conductivities of the pure BPOx membrane electrolyte and a Polybenzimidazole (PBI)-4BPOx composite membrane were 7.9 × 10-2 S cm-1 and 4.5 × 10-2 S cm-1 respectively at 150 °C, 5%RH. Fuel cell tests showed a significant enhancement in performance of BPOx over that of typical 5.6H3PO4-PBI membrane electrolyte. The enhancement is due to the improved ionic conductivity (3×), a higher exchange current density of the oxygen reduction (30×) and a lower membrane gas permeability (10×). Fuel cell current densities at 0.6 V were 706 and 425 mA cm-2 for BPOx and 5.6H3PO4-PBI, respectively, at 150 °C with O2 (atm).

  3. Effect of the Basic Residue on the Energetics and Dynamics of Dissociation of Phosphopeptides

    SciTech Connect

    Laskin, Julia; Kong, Ricky; Song, Tao; Chu, Ivan K.

    2012-12-15

    Time- and collision-energy-resolved surface-induced dissociation (SID) of protonated peptides containing phosphoserine (s) was studied using a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer configured for SID experiments. We examined fragmentation of three singly protonated peptides: GGGsGGG, KGGsGGG, and RGGsGGG. Fragmentation of GGGsGGG occurs under the mobile proton condition, while the ionizing proton is sequestered by the basic residue, resulting in the nonmobile proton condition in dissociation of the two basic peptides: KGGsGGG and RGGsGGG. RRKM modeling of the experimental data demonstrates that the energetics and dynamics of H3PO4 loss are different under mobile and nonmobile proton conditions. Specifically, fragmentation of GGGsGGG is characterized by a higher dissociation barrier, 1.68 eV, and higher activation entropy, 11 e.u. (e.u. = entropy unit), than fragmentation of the basic peptides. Similar threshold energies of 1.36 eV and 1.40 eV and activation entropies of -4.9 e.u. and 0.3 e.u. were obtained for KGGsGGG and RGGsGGG, respectively. We propose that the loss of H3PO4 from phosphoserine is a two-step process, in which the phosphate abstraction from the phosphorylated side chain is followed by dissociation of the ion-molecule complex.

  4. Measurement of Dielectric Properties and Microwave-Assisted Homogeneous Acid-Catalyzed Transesterification in a Monomode Reactor.

    PubMed

    Dall'Oglio, Evandro L; de Sousa, Paulo T; Campos, Deibnasser C; de Vasconcelos, Leonardo Gomes; da Silva, Alan Cândido; Ribeiro, Fabilene; Rodrigues, Vaniomar; Kuhnen, Carlos Alberto

    2015-08-27

    Microwave heating technology is dependent on the dielectric properties of the materials being processed. The dielectric properties of H2SO4, H3PO4, ClSO3H, and H3CSO3H were investigated in this study using a vector network analyzer in an open-ended coaxial probe method at various temperatures. Phosphoric and sulfuric acids presented higher loss tangents in the frequency range 0.3-13 GHz, reflecting greater mobility of the ions and counterions. The acids were employed as catalysts in microwave-assisted homogeneous transesterification reactions for the production of methylic and ethylic biodiesel. The effects of catalyst concentration, alcohol to oil molar ratio, and irradiation time on biodiesel conversions were investigated. The results showed a significant reduction in the reaction time for microwave-assisted transesterification reactions as compared to times for conventional heating. Also, despite its higher loss tangent, it was observed that H3PO4 leads to lower conversion to biodiesel, which can be explained by its lower carbonyl protonation capacity. PMID:26244612

  5. Optimisation of gelatin extraction from Unicorn leatherjacket (Aluterus monoceros) skin waste: response surface approach.

    PubMed

    Hanjabam, Mandakini Devi; Kannaiyan, Sathish Kumar; Kamei, Gaihiamngam; Jakhar, Jitender Kumar; Chouksey, Mithlesh Kumar; Gudipati, Venkateshwarlu

    2015-02-01

    Physical properties of gelatin extracted from Unicorn leatherjacket (Aluterus monoceros) skin, which is generated as a waste from fish processing industries, were optimised using Response Surface Methodology (RSM). A Box-Behnken design was used to study the combined effects of three independent variables, namely phosphoric acid (H3PO4) concentration (0.15-0.25 M), extraction temperature (40-50 °C) and extraction time (4-12 h) on different responses like yield, gel strength and melting point of gelatin. The optimum conditions derived by RSM for the yield (10.58%) were 0.2 M H3PO4 for 9.01 h of extraction time and hot water extraction of 45.83 °C. The maximum achieved gel strength and melting point was 138.54 g and 22.61 °C respectively. Extraction time was found to be most influencing variable and had a positive coefficient on yield and negative coefficient on gel strength and melting point. The results indicated that Unicorn leatherjacket skins can be a source of gelatin having mild gel strength and melting point. PMID:25694708

  6. Effect of sulfuric and phosphoric acid pretreatments on enzymatic hydrolysis of corn stover.

    PubMed

    Um, Byung-Hwan; Karim, M; Henk, Linda

    2003-01-01

    The pretreatment of corn stover with H2SO4 and H3PO4 was investigated. Pretreatments were carried out from 30 to 120 min in a batch reactor at 121 degrees C, with acid concentrations ranging from 0 to 2% (w/v) at a solid concentration of 5% (w/v). Pretreated corn stover was washed with distilled water until the filtrate was adjusted to pH 7.0, followed by surfactant swelling of the cellulosic fraction in a 0-10% (w/v) solution of Tween-80 at room temperature for 12 h. The dilute acid treatment proved to be a very effective method in terms of hemicellulose recovery and cellulose digestibility. Hemicellulose recovery was 62-90%, and enzymatic digestibility of the cellulose that remained in the solid was >80% with 2% (w/v) acid. In all cases studied, the performance of H2SO4 pretreatment (hemicellulose recovery and cellulose digestibility) was significantly better than obtained with H3PO4. Enzymatic hydrolysis was more effective using surfactant than without it, producing 10-20% more sugar. Furthermore, digestibility was investigated as a function of hemicellulose removal. It was found that digestibility was more directly related to hemicellulose removal than to delignification. PMID:12721479

  7. Development of polymer electrolyte membranes for fuel cells to be operated at high temperature and low humidity

    NASA Astrophysics Data System (ADS)

    Zhou, Zhen

    Polymer electrolyte membrane fuel cells (PEMFCs) have been looked at as potential alternative energy conversion devices to conventional energy conversion systems such as combustion engines. Proton conducting membranes (PEMs) are one critical component of PEMFCs. The development of novel electrolyte membranes with dense structure, good mechanical flexibility, and high proton conductivity, but with little or no dependence on humidity at temperatures above 100°C remains an important challenge to the realization of practical PEM fuel cells. In this thesis, to solve the technical difficulties existing in current high temperature PEM systems based on H3PO4 and imidazole, a new type of proton conducting species 1H-1,2,3-triazole has been explored, and proved to have high proton conductivity and also enough electrochemical stability for fuel cell applications. In further experiments, effective methods have been developed to synthesize triazole derivatives and polymers. The properties of the synthesized polymers have studied and reported in this thesis. Preliminary computational simulations have also been performed to study the proton conducting mechanism to provide intrinsic information of the proton conducting process in 1H-1,2,3-triazole. In the final part, research works on other proton conducting species including H3PO4 and other heterocycles have been reported.

  8. Effect of acid dopants in biodegradable gel polymer electrolyte and the performance in an electrochemical double layer capacitor

    NASA Astrophysics Data System (ADS)

    Sudhakar, Y. N.; Selvakumar, M.; Krishna Bhat, D.

    2015-09-01

    Proton-conducting biodegradable gellan gum gel polymer electrolytes (GPEs) have been prepared using three different dopants, namely ortho-phosphoric (o-H3PO4), sulfuric (H2SO4) and hydrochloric acids (HCl). The GPEs were cross-linked using borax. The polymeric gels were characterized by spectroscopic, thermal, ionic conductivities and dielectric measurements. Proton conductivity was in the range of 5.1 × 10-3 to 3.7 × 10-4 s cm-1 and activation energies were between 0.14 meV and 0.19 meV, at different temperatures. Among the doped acids, the H3PO4 doped GPE exhibited thermal stability at varying temperature. Electrochemical double layer capacitors (EDLCs) were fabricated using activated carbon as electrode material and GPEs. The EDLCs were tested using cyclic voltammetry, ac impedance spectroscopic and galvanostatic charge-discharge techniques. The maximum specific capacitance value was 146 F g-1 at a scan rate of 2 mV s-1. Quite stable values were obtained at a constant current density up to 1000 cycles.

  9. Aripiprazole salts IV. Anionic plus solvato networks defining molecular conformation

    NASA Astrophysics Data System (ADS)

    Freire, Eleonora; Polla, Griselda; Baggio, Ricardo

    2014-06-01

    Five new examples of aripiprazole (arip) salts are presented, viz., the Harip phthalate [Harip+·C8H5O4-(I)], homophthalate [Harip+·C9H7O4-(II)] and thiosalicilate [Harip+·C7H4O2S-(III)] salts on one side, and two different dihidrogenphosphates, Harip+·H2PO4-·2(H3PO4)·H2O (IV) and Harip+·H2PO4-·H3PO4(V). Regarding the internal structure of the aripH+ cations, they do not differ from the already known moieties in bond distances and angles, while interesting differences in conformation can be observed, setting them apart in two groups: those in I, II and III present similar conformations to those in the so far reported arip salts presenting the same centrosymmetric R(8)22 dimeric synthon, but different to those in IV and V. In parallel, the anion (+ acid) groups define bulky systems of different dimensionality (1D in the former group, 2D in the latter). The correlation between arip molecular conformation and anionic network type is discussed. An interesting feature arises with the water solvato molecule in IV, disordered around an inversion center, in regard with its interaction with an (also disordered) phosphato O-H, in a way that an “orderly disordered” H-bonding scheme arises, complying with the S.G. symmetry requirements only on average.

  10. High-temperature supercapacitor with a proton-conducting metal pyrophosphate electrolyte

    PubMed Central

    Hibino, Takashi; Kobayashi, Kazuyo; Nagao, Masahiro; Kawasaki, Shinji

    2015-01-01

    Expanding the range of supercapacitor operation to temperatures above 100°C is important because this would enable capacitors to operate under the severe conditions required for next-generation energy storage devices. In this study, we address this challenge by the fabrication of a solid-state supercapacitor with a proton-conducting Sn0.95Al0.05H0.05P2O7 (SAPO)-polytetrafluoroethylene (PTFE) composite electrolyte and a highly condensed H3PO4 electrode ionomer. At a temperature of 200°C, the SAPO-PTFE electrolyte exhibits a high proton conductivity of 0.02?S cm?1 and a wide withstanding voltage range of ±2?V. The H3PO4 ionomer also has good wettability with micropore-rich activated carbon, which realizes a capacitance of 210 F g?1 at 200°C. The resulting supercapacitor exhibits an energy density of 32?Wh kg?1 at 3?A g?1 and stable cyclability after 7000 cycles from room temperature to 150°C. PMID:25600936

  11. Removal of BrO3 (-) from drinking water samples using newly developed agricultural waste-based activated carbon and its determination by ultra-performance liquid chromatography-mass spectrometry.

    PubMed

    Naushad, Mu; Khan, Mohammad R; ALOthman, Zeid A; AlSohaimi, Ibrahim; Rodriguez-Reinoso, Francisco; Turki, Turki M; Ali, Rahmat

    2015-10-01

    Activated carbon was prepared from date pits via chemical activation with H3PO4. The effects of activating agent concentration and activation temperature on the yield and surface area were studied. The optimal activated carbon was prepared at 450 °C using 55 % H3PO4. The prepared activated carbon was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer, Emmett, and Teller (BET) surface area. The prepared date pit-based activated carbon (DAC) was used for the removal of bromate (BrO3 (-)). The concentration of BrO3 (-) was determined by ultra-performance liquid chromatography-mass tandem spectrometry (UPLC-MS/MS). The experimental equilibrium data for BrO3 (-) adsorption onto DAC was well fitted to the Langmuir isotherm model and showed maximum monolayer adsorption capacity of 25.64 mg g(-1). The adsorption kinetics of BrO3 (-) adsorption was very well represented by the pseudo-first-order equation. The analytical application of DAC for the analysis of real water samples was studied with very promising results. PMID:26040265

  12. A flexible all-inorganic fuel cell membrane with conductivity above Nafion, and durable operation at 150 °C

    NASA Astrophysics Data System (ADS)

    Ansari, Y.; Tucker, T. G.; Huang, W.; Klein, I. S.; Lee, S.-Y.; Yarger, J. L.; Angell, C. A.

    2016-01-01

    The search for fuel cell membranes has focused on carbon backbone polymers, among which Nafion seems to best survive the most severe of the degradation mechanisms - attack by peroxide radicals. Less attention has been given to inorganic membranes because of their generally inflexible nature and lower conductivity, though some SiO2-Nafion composites have shown improved properties. Nafion dominates, despite needing hydration, which then restricts operation to below 100 °C (so CO poisoning problems persist). Described herein is a low cost, flexible, and all-inorganic fiberglass reinforced gel membrane with conductivity exceeding that of Nafion at any temperature above 60 °C. Using Teflon fuel cells, maximum currents > 1 Acm-2 and OCV of 1.03 V at 150 °C are demonstrated. No detectable loss of cell potential was observed over 24 h during 50 mAcm-2 constant current operation at 120 °C while, at 150 °C and maximum power, the degradation rate is intermediate among other high conductivity H3PO4-PBI type membranes. The structure of the membrane is deduced, mainly from 29Si solid state-NMR. The -115 ppm resonance, which is extreme for Q4 Si(O) structures, identifies a zeolite-like SiO2 network, which is "floppy". 31P and 1H NMR establish nano-permeating H3PO4 as the source of the exceptional conductivity.

  13. [Behavior of N-methylcarbamate pesticides during refinement processing of edible oils].

    PubMed

    Fukazawa, Toru; Kobayashi, Tetsushi; Tokairin, Shigeru; Chimi, Kenji; Maruyama, Takenori; Yanagita, Teruyoshi

    2007-01-01

    The following N-methylcarbamate pesticides, aldicarb, aldicarb sulfoxide, aldicarb sulfone, oxamyl, methomyl, thiodicarb, propoxur, carbofuran, carbosulfan, benfuracarb, bendiocarb, carbaryl, fenobcarb and furathiocarb, were added to soybean oil, each at 5 mg/kg(5 ppm), followed by degumming, alkali refining, bleaching and deodorization for oil refinement. Residual pesticide content in each case was determined immediately after refining. DEGUMMING: Aldicarb, aldicarb sulfoxide, aldicarb sulfone, oxamyl, thiodicarb, carbosulfan, benfuracarb were each found to decrease by as much as 70% by H(3)PO(4) treatment, this being less than 26% noted for the other pesticides. With hot water treatment, the decrease in any one pesticide was less than 52%. ALKALI REFINING: The rate of decrease varied with the pesticide, ranging from 8% to 100%. 200%NaOH were effectively brought about pesticide removal, compared to 125%NaOH. BLEACHING: Aldicarb, aldicarb sulfoxide, aldicarb sulfone, oxamyl, methomyl, thiodicarb, carbosulfan, benfuracarb, bendiocarb and furathiocarb each decreased by more than 80% with activated clay containing activated charcoal. Carbaryl decreased remarkably by this clay. Pesticide removal in all cases was at less than 30%. DEODORIZATION: 40% Furathiocarb, 14% carbosulfan, 11% benfuracarb and 3% carbofuran could still be detected subsequent to deodorization at 260 degrees C while all other pesticide amounts were too small to permit quantitative detection. Degumming with H(3)PO(4) and bleaching with activated clay caused the conversion of carbosulfan and benfuracarb into carbofuran. Carbofuran and furathiocarb may thus possibly still remain in the oil following the above 4 refinement processes. PMID:17898465

  14. Phase separation and crystallization in sodium lanthanum phosphate glasses induced by electrochemical substitution of sodium ions with protons.

    PubMed

    Kawaguchi, Keiga; Yamaguchi, Takuya; Omata, Takahisa; Yamashita, Toshiharu; Kawazoe, Hiroshi; Nishii, Junji

    2015-09-21

    Electrochemical substitution of sodium ions with protons (alkali-proton substitution; APS), and the injection of proton carriers was applied to sodium lanthanum phosphate glasses. A clear and homogeneous material was obtained for a glass of composition 25NaO1/2-8LaO3/2-66PO5/2-1GeO2 following APS, with a resulting proton conductivity of 4 × 10(-6) S cm(-1) at 250 °C. The glass underwent phase separation and crystallization at temperatures >255 °C, forming a highly hygroscopic and proton conducting H3PO4 phase in addition to LaP5O14 and other unidentified phases. A glass of composition 25NaO1/2-8LaO3/2-67PO5/2 underwent phase separation and crystallization during APS, forming both H3PO4 and LaP5O14 phases. Sodium lanthanum phosphate glasses are prone to phase separation and crystallization during APS unlike the previously reported NaO1/2-WO3-NbO5/2-LaO3/2-PO5/2 glasses. The phase separation was explained by a reduction in viscosity following APS and the introduction of protons, which exhibit high field strength. Thus, phase separation and crystallization of glasses during APS was difficult to avoid. An approach to suppress phase separation is discussed. PMID:26265082

  15. Effect of counterions on the physical properties of l-arginine in frozen solutions and freeze-dried solids.

    PubMed

    Izutsu, Ken-Ichi; Fujimaki, Yasuto; Kuwabara, Akiko; Aoyagi, Nobuo

    2005-09-14

    The objective of this study was to elucidate the physical properties of L-arginine and various counterion combinations in frozen aqueous solutions and in freeze-dried solids. L-Arginine remains amorphous in the highly concentrated non-ice phase in frozen solutions with a Tg (glass transition temperature of maximally freeze-concentrated solutes) of -41.4 degrees C. Some acids and salts (e.g., H3PO4, H2SO4, HNO3, and NaH2PO4) raised the Tg , whereas others (e.g., HCl, CH3COOH, HCOOH, Na2HPO4, and NaCl) had little effect or lowered the L-arginine Tg . Co-lyophilization with phosphoric acid also raised the glass transition temperature (Tg) of amorphous freeze-dried L-arginine solids. Arginine-H3PO4 combinations exhibited properties that led to either the stabilization or destabilization of a model protein (lactate dehydrogenase: LDH) during freeze-drying, depending on their concentration ratios. Fourier-transform infrared (FT-IR) and diffusion reflectance near-infrared (NIR) spectra indicated the presence of interactions between the amino and/or guanidyl groups of L-arginine and phosphate ions in the amorphous freeze-dried cakes. It was postulated that the interaction between L-arginine and the multivalent counterions, as well as an increase in hydrogen bonding network, reduced the mobility of molecules in the frozen solutions and freeze-dried solids. PMID:16026945

  16. Influence of calcium hydroxide on the fate of perfluorooctanesulfonate under thermal conditions.

    PubMed

    Wang, Fei; Lu, Xingwen; Shih, Kaimin; Liu, Chengshuai

    2011-09-15

    To explore the potential fate and transport of perfluorochemicals in the thermal treatment of sludge, perfluorooctanesulfonate (PFOS), a perfluorochemical species commonly dominant in wastewater sludge, was mixed with hydrated lime (Ca(OH)(2)) to quantitatively observe their interaction under different temperatures. The phase compositions of the mixtures after the reactions were qualitatively identified and quantitatively determined using X-ray diffraction technique. The results of the thermogravimetry and differential scanning calorimetry analyses indicate that PFOS gasified directly during the thermal treatment process when the temperature was increased to around 425 °C. However, the formation of CaF(2) at 350 °C suggests that the presence of Ca(OH)(2) in the mixture can lead to the decomposition of PFOS at 350 °C, which is lower than the decomposition temperature of PFOS alone (425 °C). The increase of temperature promoted a solid state reaction between PFOS and Ca(OH)(2), and also enhanced the interaction between the gaseous products of PFOS and CaO (or Ca(OH)(2)). The preferred Ca/F molar ratio to achieve fluorine stabilization by Ca(OH)(2) was above 1:1 in the experiment involving 400 °C and 600 °C treatment. It also showed that equilibrium efficiency is achieved within 5 min at 400 °C and within 1 min above 600°C. PMID:21719193

  17. Long term effect of alkali types on waste activated sludge hydrolytic acidification and microbial community at low temperature.

    PubMed

    Jin, Baodan; Wang, Shuying; Xing, Liqun; Li, Baikun; Peng, Yongzhen

    2016-01-01

    The effect of four alkali reagents (NaOH, KOH, Ca(OH)2, mixed alkali) on waste activated sludge (WAS) hydrolytic acidification and microbial community was studied in semi-continuous fermentation systems at low temperature (15°C) over long term operational time (65day). The results showed that protein and polysaccharide of NaOH (124.26, 11.92) was similar to that of KOH (109.53, 11.30), both were higher than Ca(OH)2 (70.66, 3.74) and mixed alkali (90.66, 8.71). The short chain fatty acids (SCFAs) of NaOH (231.62) was higher than KOH (220.62mg chemical oxygen demand (COD)/g VSS). Although Ca(OH)2 system had strong acidification capacity, the shortage of SCFAs occurred due to the low activity of hydrolase. Illumina MiSeq sequencing revealed that Tissierella and Erysipelothrix were enriched in the NaOH and Ca(OH)2 systems, where Peptostreptococcaceae incertae_sedis was enriched in the NaOH and KOH systems, less Anaerolinea was involved in Ca(OH)2 condition. PMID:26546788

  18. Low temperature calcium hydroxide treatment enhances anaerobic methane production from (extruded) biomass.

    PubMed

    Khor, Way Cern; Rabaey, Korneel; Vervaeren, Han

    2015-01-01

    Ca(OH)2 treatment was applied to enhance methane yield. Different alkali concentration, incubation temperature and duration were evaluated for their effect on methane production and COD conversion efficiency from (non-)extruded biomass during mesophilic anaerobic digestion at lab-scale. An optimum Ca(OH)2 pretreatment for grass is found at 7.5% lime loading at 10°C for 20h (37.3% surplus), while mild (50°C) and high temperatures perform sub-optimal. Ca(OH)2 post-treatment after fast extrusion gives an additional surplus compared to extruded material of 15.2% (grass), 11.2% (maize straw) and 8.2% (sprout stem) regarding methane production. COD conversion improves accordingly, with additional improvements of 10.3% (grass), 9.0% (maize straw) and 6.8% (sprout stem) by Ca(OH)2 post-treatment. Therefore, Ca(OH)2 pretreatment and post-treatment at low temperature generate an additional effect regarding methane production and COD conversion efficiency. Fast extrusion gives a higher energy efficiency ratio compared to slow extrusion. PMID:25461001

  19. Fabrication of porous calcite using chopped nylon fiber and its evaluation using rats.

    PubMed

    Ishikawa, Kunio; Tram, Nguyen Xuan Thanh; Tsuru, Kanji; Toita, Riki

    2015-02-01

    Although porous calcite has attracted attention as bone substitutes, limited studies have been made so far. In the present study, porous calcite block was fabricated by introducing chopped nylon fiber as porogen. Ca(OH)2 powder containing 10 wt% chopped nylon fiber was compacted at 150 MPa, and sintered to burn out the fiber and to carbonate the Ca(OH)2 under stream of 1:2 O2-CO2. Sintering of Ca(OH)2 at 750 °C or lower temperature resulted in incomplete burning out of the fiber whereas sintering at 800 °C or higher temperature resulted in the formation of CaO due to the thermal decomposition of Ca(OH)2. However, sintering at 770 °C resulted in complete burning out of the fiber and complete carbonation of Ca(OH)2 to calcite without forming CaO. Macro- and micro-porosities of the porous calcite were approximately 23 and 16%, respectively. Diameter of the macropores was approximately 100 ?m which is suitable for bone tissue penetration. Porous calcite block fabricated by this method exhibited good tissue response when implanted in the bone defect in femur of 12-weeks-old rat. Four weeks after implantation, bone bonded on the surface of calcite. Furthermore, bone tissue penetrated interior to the macropore at 8 weeks. These results demonstrated the good potential value of porous calcite as artificial bone substitutes. PMID:25649514

  20. Pretreatment of empty palm fruit bunch for production of chemicals via catalytic pyrolysis.

    PubMed

    Misson, Mailin; Haron, Roslindawati; Kamaroddin, Mohd Fadhzir Ahmad; Amin, Nor Aishah Saidina

    2009-06-01

    The effect of chemical pretreatments using NaOH, H(2)O(2), and Ca(OH)(2) on Empty Palm Fruit Bunches (EPFB) to degrade EPFB lignin before pyrolysis was investigated. Spectrophotometer analysis proved consecutive addition of NaOH and H(2)O(2) decomposed almost 100% of EPFB lignin compared to 44% for the Ca(OH)(2), H(2)O(2) system while NaOH and Ca(OH)(2) used exclusively could not alter lignin much. Next, the pretreated EPFB was catalytically pyrolyzed. Experimental results indicated the phenolic yields over Al-MCM-41 and HZSM-5 catalysts were 90 wt% and 80 wt%, respectively compared to 67 wt% yield for the untreated sample under the same set of conditions. Meanwhile, the experiments with HY zeolite yielded 70 wt% phenols. PMID:19232488

  1. Element composition and mineralogical characterisation of air pollution control residue from UK energy-from-waste facilities.

    PubMed

    Bogush, Anna; Stegemann, Julia A; Wood, Ian; Roy, Amitava

    2015-02-01

    Air pollution control (APC) residues from energy-from-waste (EfW) are alkaline (corrosive) and contain high concentrations of metals, such as zinc and lead, and soluble salts, such as chlorides and sulphates. The EPA 3050B-extractable concentrations of 66 elements, including critical elements of strategic importance for advanced electronics and energy technologies, were determined in eight APC residues from six UK EfW facilities. The concentrations of Ag (6-15 mg/kg) and In (1-13 mg/kg), as well as potential pollutants, especially Zn (0.26-0.73 wt.%), Pb (0.05-0.2 wt.%), As, Cd, Cu, Mo, Sb, Sn and Se were found to be enriched in all APC residues compared to average crustal abundances. Results from a combination of scanning electron microscopy with energy dispersive X-ray spectroscopy and also powder X-ray diffraction, thermal analysis and Fourier transform infrared spectroscopy give an exceptionally full understanding of the mineralogy of these residues, which is discussed in the context of other results in the literature. The present work has shown that the bulk of the crystalline phases present in the investigated APC residues include Ca-based phases, such as CaCl(x)OH(2-x), CaCO3, Ca(OH)2, CaSO4, and CaO, as well as soluble salts, such as NaCl and KCl. Poorly-crystalline aragonite was identified by FTIR. Sulphur appears to have complex redox speciation, presenting as both anhydrite and hannebachite in some UK EfW APC residues. Hazardous elements (Zn and Pb) were widely associated with soluble Ca- and Cl-bearing phases (e.g. CaCl(x)OH(2-x) and sylvite), as well as unburnt organic matter and aluminosilicates. Specific metal-bearing minerals were also detected in some samples: e.g., Pb present as cerussite; Zn in gahnite, zincowoodwardite and copper nickel zinc oxide; Cu in tenorite, copper nickel zinc oxide and fedotovite. Aluminium foil pieces were present and abundantly covered by fine phases, particularly in any cracks, probably in the form of Friedel's salt. PMID:25541041

  2. Effectiveness of four different techniques in removing intracanal medicament from the root canals: An in vitro study

    PubMed Central

    Bhuyan, A. C.; Seal, Mukut; Pendharkar, Kartik

    2015-01-01

    Aim: To evaluate the effectiveness of different techniques in removing calcium hydroxide (Ca(OH)2) from the root canal. Materials and Methods: Twenty-four freshly extracted mandibular premolars were instrumented using ProTaper rotary instruments. The teeth were longitudinally split into two halves, cleaned of debris. The two halves were then reassembled and filled with Ca(OH)2 and were divided into four groups. In Group I, the teeth were irrigated with 5 mL of 2.5% sodium hypochlorite (NaOCl) and 5 mL of 17% of ethylenediaminetetraacetic acid. In Group II, the teeth were irrigated with 5 mL of 2.5% NaOCl and a rotary ProTaper F3 instrument was used. In Group III, the teeth were irrigated with 5 mL of 2.5% NaOCl and agitated using an ultrasonic unit. In Group IV, the teeth were irrigated with 5 mL of 2.5% NaOCl and a CanalBrush was used to remove Ca(OH)2. The roots were disassembled, and photographs were taken. The amount of residual Ca(OH)2 was calculated using an image analysis software as a percentage of the total canal surface area. The data were analyzed using one-way analysis of variance and post-hoc Tukey test. Results: CanalBrush and ultrasonic techniques showed significantly less residual Ca(OH)2 than irrigants and rotary techniques. There was no significant difference between the rotary and irrigant techniques. Conclusion: None of the techniques used were completely able to remove Ca(OH)2 from the root canals. But the CanalBrush and ultrasonic techniques were significantly better than the rotary instrument and irrigant groups. PMID:26321826

  3. Alcohol dispersions of calcium hydroxide nanoparticles for stone conservation.

    PubMed

    Rodriguez-Navarro, Carlos; Suzuki, Amelia; Ruiz-Agudo, Encarnacion

    2013-09-10

    Alcohol dispersions of Ca(OH)2 nanoparticles, the so-called nanolimes, are emerging as an effective conservation material for the consolidation of stone, mortars, and plasters present in old masonry and/or mural paintings. To better understand how this treatment operates, to optimize its performance and broaden its applications, here we study the nano and microstructural characteristics, carbonation behavior, and consolidation efficacy of colloidal alcohol dispersions of Ca(OH)2 nanoparticles produced by both homogeneous (commercial nanolime) and heterogeneous phase synthesis (aged slaked lime and carbide lime putties). We observe that the alcohol not only provides a high colloidal stability to Ca(OH)2 particles, but also affects the kinetics of carbonation and CaCO3 polymorph selection. This is due to the pseudomorphic replacement of Ca(OH)2 particles by calcium alkoxides upon reaction with ethanol or 2-propanol. The extent of this replacement reaction depends on Ca(OH)2 size and time. Hydrolysis of alkoxides speeds up the carbonation process and increases the CaCO3 yield. The higher degree of transformation into calcium alkoxide of both the commercial nanolime and the carbide lime fosters metastable vaterite formation, while calcite precipitation is promoted upon carbonation of the aged slaked lime due its lower reactivity, which limits calcium alkoxide formation. A higher consolidation efficacy in terms of strength gain of treated porous stone is achieved in the latter case, despite the fact that the carbonation is much faster and reaches a higher yield in the former ones. Formation of alkoxides, which has been neglected in previous studies, needs to be considered when applying nanolime treatments. These results show that the use Ca(OH)2 nanoparticle dispersions prepared with either aged slaked lime or carbide lime putties is an economical and effective conservation alternative to commercial nanolimes produced by homogeneous phase synthesis. Ultimately, this study contributes to show that nanotechnology can help saving the built and sculptural heritage. PMID:23919634

  4. Microstructure characteristics of concrete incorporating metakaolin and PVA fibers and influence on the compressive strength

    NASA Astrophysics Data System (ADS)

    Khan, Sadaqat Ullah; Shafiq, Nasir; Ayub, Tehmina

    2015-07-01

    In this paper, microstructure of concrete is investigated using metakaolin (MK) as cement replacing material and Polyvinyl Alcohol (PVA) fibers. Total ten (10) mixes of concrete are examined by varying PVA fiber aspect ratio. It was found that MK refines the pore structure, improves interfacial transition zone (ITZ) due to its pozzolanic effects, reduces portlandite (Ca(OH)2) content and bridges the gap between matrix and aggregates due to finer particle size. Due to improvement in ITZ, the compressive strength was improved. There was no indication of Ca(OH)2 around the PVA fibers in the presence of MK and the interface between the fiber and matrix was observed very narrow.

  5. Thermochemical energy storage for a lunar base

    SciTech Connect

    Perez-Davis, M.E.; McKissock, B.I.; Difilippo, F.

    1992-01-01

    A thermochemical solar energy storage concept involving the reversible reaction CaO + H2O yields Ca(OH)2 is proposed as a power system element for a lunar base. The operation and components of such a system are described. The CaO/H2O system is capable of generating electric power during both the day and night. Mass of the required amount of CaO is neglected since it is obtained from lunar soil. Potential technical problems, such as reactor design and lunar soil processing, are reviewed.

  6. Acid and alkali doped PBI electrolyte in electrochemical system

    NASA Astrophysics Data System (ADS)

    Xing, Baozhong

    In this work the conductivity of blank PBI membrane, acid doped PBI and alkaline doped PBI was systematically studied. A new methodology for sorption kinetics study in electrolyte solution has been established by monitoring the conductivity change during the sorption process. The model of the doping process and mechanism of conductivity are proposed. The performance of PBI (doped under optimum conditions) in fuel cell as PEM was evaluated. The experimental results show that the blank PBI in acid solution is an ionic insulator. It clarified the long time confusion in this area. The acid doped PBI membrane is an ionic conductor. The conductivity increases with the concentration of the acid solution. In high concentration acid solution, the conductivity increases with the type of acid in the order: H2SO 4 > H3PO4 > HClO4 > HNO3 > HCl. The kinetics of the doping process was studied, by a continuous method. The ionic conductivity mechanism was established. The PBI membranes doped with H2SO4 and H3PO4 exhibit better performance than NafionRTM. The doped FBI has more resistance to CO poison. 3% CO in H2 has little effect on the H3PO 4 doped PBI membrane at 185°C. The conductivity of the alkali doped PBI membrane changes with the concentration of the alkaline solution and the type of the alkalis. The conductivity has a maximum in KOH and NaOH solution. The maximum conductivity in KOH is higher than in NaOH and LiOH. It is about 5 times of that of NafionRTM in alkaline solution. The two-step sorption process in alkaline solution was observed. The first step is the permeation process of the alkalis in the PBI membrane. The permeation is the results of diffusion and interaction. It is concluded that the permeation process is controlled by the rate of interaction between the alkali and PBI molecule. The second step is the relaxation process in the membrane. This step contributes more to the conductivity for the membrane than the first step. The ionic conductivity mechanism was established. In solution the cations and OH- all participate in the transport of current. It is the OH- that breaks the bonds between PBI molecules and enables the cations pass through the membrane. The performance of alkali doped PBI (doped under optimum conditions) in fuel cell as PEM is as good as NafionRTM.

  7. Hydrogeochemical contrasts between low and high arsenic groundwater and its implications for arsenic mobilization in shallow aquifers of the northern Yinchuan Basin, P.R. China

    NASA Astrophysics Data System (ADS)

    Guo, Qi; Guo, Huaming; Yang, Yuance; Han, Shuangbao; Zhang, Fucun

    2014-10-01

    Little is known about hydrogeochemical contrasts between low and high As groundwaters and their connection to As mobilization in the Yinchuan Basin. Investigations were carried out to evaluate As distribution and geochemical processes for As mobilization in three regions, including piedmont proluvial fans (PA), dry farmland (DF) and paddy farmland (PF). Ninety-two groundwater samples, 4 surface water samples, and 66 sediments samples were collected and analyzed for chemical and isotopic components. Results show that low As groundwater is generally found in PA. However, high As concentrations (up to 105 ?g L-1) are mainly observed in groundwaters from DF and PF, which are associated with reducing conditions. High As groundwater is characterized by high concentrations of NH4+, dissolved Mn, dissolved Fe and Fe(II), and low concentrations of NO3- and SO42-. The intensive irrigation in PF recharges the aquifers by vertical infiltration of the diverted Yellow River water, and leads to the higher redox potentials and the lower dissolved As in comparison with those in DF. Environmental isotopes (?18O and ?D) show that evaporation due to the intensive irrigation plays a minor role in As enrichment. The positive correlation between As and dissolved Fe suggests that groundwater As would result from the reductive dissolution of Fe oxides. Besides, dissolved P may be involved in competing with As for binding sites on Fe oxide minerals. Sediment As ranges between 3.94 and 75.2 mg kg-1. HCl-leached As accounts for 60% of total As in the sediments, while H3PO4-leached As accounts for 5%. Depth-matched samples show a good correlation between dissolved As and H3PO4-leached As in sediments. Arsenic distribution coefficient (Kd), calculated from H3PO4-leached As and dissolved As, ranges between 5.08 and 17.3 cm3 g-1, which generally depends on groundwater redox potentials. In reducing conditions, low values are found with As being preferentially partitioned into groundwater.

  8. Part 2: Sensitivity comparisons of the insect Centroptilum triangulifer to Ceriodaphnia dubia and Daphnia magna using standard reference toxicants; NaCl, KCl and CuSO4

    EPA Science Inventory

    Criteria for establishing water quality standards that are protective of all native biota are generally based upon laboratory toxicity tests. These test utilize common model organisms that have established test methods. However, only a small portion of species have established ...

  9. Titanium subhydride potassium perchlorate (TiH1.65/KClO4) burn rates from hybrid closed bomb-strand burner experiments.

    SciTech Connect

    Cooper, Marcia A.; Oliver, Michael S.

    2012-08-01

    A hybrid closed bomb-strand burner is used to measure the burning behavior of the titanium subhydride potassium perchlorate pyrotechnic with an equivalent hydrogen concentration of 1.65. This experimental facility allows for simultaneous measurement of the closed bomb pressure rise and pyrotechnic burn rate as detected by electrical break wires over a range of pressures. Strands were formed by pressing the pyrotechnic powders to bulk densities between 60% and 90% theoretical maximum density. The burn rate dependance on initial density and vessel pressure are measured. At all initial strand densities, the burn is observed to transition from conductive to convective burning within the strand. The measured vessel pressure history is further analyzed following the closed bomb analysis methods developed for solid propellants.

  10. Excretion of NaCl and KCl loads in mosquitoes. 2. Effects of the small molecule Kir channel modulator VU573 and its inactive analog VU342

    PubMed Central

    Rouhier, Matthew F.; Hine, Rebecca M.; Park, Seokhwan Terry; Raphemot, Rene; Denton, Jerod; Piermarini, Peter M.

    2014-01-01

    The effect of two small molecules VU342 and VU573 on renal functions in the yellow fever mosquito Aedes aegypti was investigated in vitro and in vivo. In isolated Malpighian tubules, VU342 (10 ?M) had no effect on the transepithelial secretion of Na+, K+, Cl?, and water. In contrast, 10 ?M VU573 first stimulated and then inhibited the transepithelial secretion of fluid when the tubules were bathed in Na+-rich or K+-rich Ringer solution. The early stimulation was blocked by bumetanide, suggesting the transient stimulation of Na-K-2Cl cotransport, and the late inhibition of fluid secretion was consistent with the known block of AeKir1, an Aedes inward rectifier K+ channel, by VU573. VU342 and VU573 at a hemolymph concentration of about 11 ?M had no effect on the diuresis triggered by hemolymph Na+ or K+ loads. VU342 at a hemolymph concentration of 420 ?M had no effect on the diuresis elicited by hemolymph Na+ or K+ loads. In contrast, the same concentration of VU573 significantly diminished the Na+ diuresis by inhibiting the urinary excretion of Na+, Cl?, and water. In K+-loaded mosquitoes, 420 ?M VU573 significantly diminished the K+ diuresis by inhibiting the urinary excretion of K+, Na+, Cl?, and water. We conclude that 1) the effects of VU573 observed in isolated Malpighian tubules are overwhelmed in vivo by the diuresis triggered with the coinjection of Na+ and K+ loads, and 2) at a hemolymph concentration of 420 ?M VU573 affects Kir channels systemically, including those that might be involved in the release of diuretic hormones. PMID:25056106

  11. NiO layers grown on a Ni substrate by galvanostatic anodization as a positive electrode material for aqueous hybrid capacitors

    NASA Astrophysics Data System (ADS)

    Chiku, Masanobu; Toda, Masanari; Higuchi, Eiji; Inoue, Hiroshi

    2015-07-01

    A NiO positive electrode for aqueous hybrid capacitors was prepared by a new galvanostatic anodization method. A thin sheet of heat-treated Ni was galvanostatically oxidized in aqueous 85% H3PO4 containing 0.5 M NH4F. During the anodization, the thickness of the Ni metal sheet decreased from 10 to 2 ?m and 2- to 3-?m-thick NiO layers were formed on both sides of the Ni metal sheet. A hybrid capacitor comprising the anodized NiO positive electrode, an activated carbon negative electrode, and aqueous 10 M KOH exhibited a maximum specific energy of 16 W h kg-1 and a specific power of 22.2 kW kg-1.

  12. Tracing environment effects that influence the stability of anion-anion complexes: The case of phosphate-phosphate interactions

    NASA Astrophysics Data System (ADS)

    Mata, Ignasi; Alkorta, Ibon; Molins, Elies; Espinosa, Enrique

    2013-01-01

    The effect of the environment on the stability of the (H3PO4)2, (HPO4-)2 and (HPO42-)2 hydrogen bonded dimers has been explored by the topological analyses of the theoretical electron density and the electrostatic potential. The environment has little effect on the hydrogen-bonding interaction, while it induces a significant one on the Coulombic component of the dimer. The interaction energy is represented in terms of hydrogen-bond and non-hydrogen-bond contributions, being only the latter affected by the charge or the environment. While the non-hydrogen bond contribution dominates the interaction energy in the gas phase, it becomes balanced in a polarizable environment.

  13. Anodically Electrodeposited Iridium Oxide Films (AEIROF) from Alkaline Solutions for Electrochromic Display Devices

    NASA Astrophysics Data System (ADS)

    Yamanaka, Kazusuke

    1989-04-01

    Anodically electrodeposited iridium oxide films from alkaline solutions were investigated for application to electrochromic devices. Micro-crystalline (diameter: 15Å) films obtained by the electrolysis of aqueous alkaline solutions containing iridium chloride, oxalic acid and potassium carbonate showed good electrochromic reaction reversibility. The coloration efficiency of the films was about one third that of typical evaporated tungsten oxide films, and the response rate measured by the amount of injected charge was about double. The cycle lives of the cells, composed of electrodeposited films, 1M H3PO4-NaOH (pH{=}3˜ 5), and an activated carbon cloth, were more than 8× 106 with a 0.6 V, 1 Hz continuous square wave.

  14. Effects of Kraft lignin on hydrolysis/dehydration of sugars, cellulosic and lignocellulosic biomass under hot compressed water.

    PubMed

    Daorattanachai, Pornlada; Viriya-empikul, Nawin; Laosiripojana, Navadol; Faungnawakij, Kajornsak

    2013-09-01

    The effect of Kraft lignin presenting on the hydrolysis and dehydration of C5 and C6 sugars, cellulose, hemicelluloses and biomass under hot compressed water (HCW) in the presence of H3PO4 catalyst was intensively studied. The lignin strongly inhibited the acid hydrolysis of cellulose and hemicellulose to glucose and xylose, respectively. Interestingly, the admixed lignin markedly promoted the isomerization of glucose to fructose, and dehydration of fructose (except at the low catalyst loading), resulting in high 5-hydroxymethylfurfural yields. Nonetheless, lignin inhibited the hydrolysis of xylan to xylose and dehydration of xylose to furfural. Moreover, the acidity of the system significantly affects the hydrolysis/dehydration of biomass. It was revealed that the presence of lignin strongly interfered the yields of sugars and furans produced from raw corncob, while the delignified corncob provided significant improvement of product yields, confirming the observed role of lignin in the biomass conversion system via sugar platforms. PMID:23907066

  15. Oxygen isotope analysis of carbonates in the calcite-dolomite-magnesite solid-solution by high-temperature pyrolysis: initial results.

    PubMed

    Crowley, Stephen F; Spero, Howard J; Winter, David A; Sloane, Hilary J; Croudace, Ian W

    2008-06-01

    Accurate and efficient measurement of the oxygen isotope composition of carbonates (delta(C) (18)O) based on the mass spectrometric analysis of CO(2) produced by reacting carbonate samples with H(3)PO(4) is compromised by: (1) uncertainties associated with fractionation factors (alpha(CO)(2)C) used to correct measured oxygen isotope values of CO(2)(delta(CO(2)(18)O) to delta(C) (18)O; and (2) the slow reaction rates of many carbonates of geological and environmental interest with H(3)PO(4). In contrast, determination of delta(C) (18)O from analysis of CO produced by high-temperature (>1400 degrees C) pyrolytic reduction, using an elemental analyser coupled to continuous-flow isotope-ratio mass spectrometry (TC/EA CF-IRMS), offers a potentially efficient alternative that measures the isotopic composition of total carbonate oxygen and should, therefore, theoretically be free of fractionation effects. The utility of the TC/EA CF-IRMS technique was tested by analysis of carbonates in the calcite-dolomite-magnesite solid-solution and comparing the results with delta(C) (18)O measured by conventional thermal decomposition/fluorination (TDF) on the same materials. Initial results show that CO yields are dependent on both the chemical composition of the carbonate and the specific pyrolysis conditions. Low gas yields (<100% of predicted yield) are associated with positive (>+0.2 per thousand) deviations in delta(C(TC/EA) (18)O compared with delta(C(TDF) (18)O. At a pyrolysis temperature of 1420 degrees C the difference between delta(C) (18)O measured by TC/EA CF-IRMS and TDF (Delta(C(TC/EA,TDF) (18)O) was found to be negatively correlated with gas yield (r = -0.785) and this suggests that delta(C) (18)O values (with an estimated combined standard uncertainty of +/-0.38 per thousand) could be derived by applying a yield-dependent correction. Increasing the pyrolysis temperature to 1500 degrees C also resulted in a statistically significant correlation with gas yield (r = -0.601), indicating that delta(C) (18)O values (with an estimated uncertainty of +/-0.43 per thousand) could again be corrected using a yield-dependent procedure. Despite significant uncertainty associated with TC/EA CF-IRMS analysis, the magnitude of the uncertainty is similar to that associated with the application of poorly defined values of alpha(CO)(2), (C) used to derive delta(C) (18)O from delta(CO(2) (18)O measured by the H(3)PO(4) method for most common carbonate phases. Consequently, TC/EA CF-IRMS could provide a rapid alternative for the analysis of these phases without any effective deterioration in relative accuracy, while analytical precision could be improved by increasing the number of replicate analyses for both calibration standards and samples. Although automated gas preparation techniques based on the H(3)PO(4) method (ISOCARB, Kiel device, Gas-Bench systems) have the potential to measure delta(CO)(2) (18)O efficiently for specific, slowly reacting phases (e.g. dolomite), problems associated with poorly defined alpha(CO)(2), (C) remain. The application of the Principle of Identical Treatment is not a solution to the analysis of these phases because it assumes that a single fractionation factor may be defined for each phase within a solid-solution regardless of its precise chemical composition. This assumption has yet to be tested adequately. PMID:18446821

  16. The GA sulfur-iodine water-splitting process - A status report

    NASA Technical Reports Server (NTRS)

    Besenbruch, G. E.; Chiger, H. D.; Mccorkle, K. H.; Norman, J. H.; Rode, J. S.; Schuster, J. R.; Trester, P. W.

    1981-01-01

    The development of a sulfur-iodine thermal water splitting cycle is described. The process features a 50% thermal efficiency, plus all liquid and gas handling. Basic chemical investigations comprised the development of multitemperature and multistage sulfuric acid boost reactors, defining the phase behavior of the HI/I2/H2O/H3PO4 mixtures, and development of a decomposition process for hydrogen iodide in the liquid phase. Initial process engineering studies have led to a 47% efficiency, improvements of 2% projected, followed by coupling high-temperature solar concentrators to the splitting processes to reduce power requirements. Conceptual flowsheets developed from bench models are provided; materials investigations have concentrated on candidates which can withstand corrosive mixtures at temperatures up to 400 deg K, with Hastelloy C-276 exhibiting the best properties for containment and heat exchange to I2.

  17. Preparation and properties of a coated slow-release and water-retention biuret phosphoramide fertilizer with superabsorbent.

    PubMed

    Jin, Shuping; Yue, Guoren; Feng, Lei; Han, Yuqi; Yu, Xinghai; Zhang, Zenghu

    2011-01-12

    In this investigation, a novel water-insoluble slow-release fertilizer, biuret polyphosphoramide (BPAM), was formulated and synthesized from urea, phosphoric acid (H(3)PO(4)), and ferric oxide (Fe(2)O(3)). The structure of BPAM was characterized by Fourier transform infrared (FTIR) spectroscopy. Subsequently, a coated slow-release BPAM fertilizer with superabsorbent was prepared by ionic cross-linked carboxymethylchitosan (the core), acrylic acid, acrylamide, and active carbon (the coating). The variable influences on the water absorbency were investigated and optimized. Component analysis results showed that the coated slow-release BPAM contained 5.66% nitrogen and 11.7% phosphorus. The property of water retention, the behavior of slow release of phosphorus, and the capacity of adsorption of cations were evaluated, and the results revealed that the product not only had good slow-release property and excellent water retention capacity but also higher adsorption capacities of cations in saline soil. PMID:21155599

  18. The fractionation of noble gases in diamonds of CV3 Efremovka chondrite

    NASA Technical Reports Server (NTRS)

    Fisenko, A. V.; Verchovsky, A. B.; Semjonova, L. F.; Shukolyukov, Yu. A.

    1993-01-01

    It was shown that in diamonds of Efremovka CV3 the noble gases with normal isotopic compositions are fractionated in different degree while the correlation of isotopic anomalous components is nearly constant. Some data for noble gases in DE-4 sample of Efremovka chondrite are considered. In contrast to DE-2 sample the DE-4 was treated except conc. HClO4, 220 C in addition with mixture of conc. H2SO4+H3PO4 (1:1), 220 C, twice. Noble gases analysis were performed in Germany at Max Plank Institute fur Chemie. Noble gases were released by oxidation of samples at stepped heating from 420 C to 810 C and by pyrolysis at 580, 590, and 680 C.

  19. [Determination of antidangdruff agent salicylic acid, zinc pyrithione, octopirox, climbazole and ketoconazole in shampoo by high performance liquid chromatography].

    PubMed

    Yang, Yan-Wei; Zhu, Ying; Su, Xiao-Qing

    2005-09-01

    A high performance liquid chromatography method was established for determination of antidangdruff agent salicylic acid,zinc pyrithione, octopirox, climbazole and ketoconazole in shampoo on a C18 column using acetonitrile-metholaqueous solution (10 mmol/L KH2 PO4 and 5 mmol/L EDTANa2, pH is adjusted to 4.0 with H3 PO4) (50:10:40) as mobile phase at a flow rate of 1.0 ml/min, with the column temperature 25 degrees C and detection wave 230nm. The precision was less than 3.8% and recovery varied from 92.7% to 104.9%. The experimental results showed that the method was simple, precise and accurate. PMID:16329615

  20. Fabrication of Monolithic Sapphire Membranes for High Tc Bolometer Array Development

    NASA Technical Reports Server (NTRS)

    Pugel, D. E.; Lakew, B.; Aslam, S.; Wang, L.

    2003-01-01

    This paper examines the effectiveness of Pt/Cr thin film masks for the architecture of monolithic membrane structures in r-plane sapphire. The development of a pinhole-free Pt/Cr composite mask that is resistant to hot H2SO4:H3PO4 etchant, will lead to the fabrication of smooth sapphire membranes whose surfaces are well-suited for the growth of low-noise high Tc films. In particular, the relationship of thermal annealing conditions on the Pt/Cr composite mask system to: (1) changes in the surface morphology and elemental concentration of the Pt/Cr thin film layers and (2) etch pit formation on the sapphire surface will be presented.

  1. Microscale steps and micro-nano combined structures by anodizing aluminum

    NASA Astrophysics Data System (ADS)

    Ding, G. Q.; Yang, R.; Ding, J. N.; Yuan, N. Y.; Shen, W. Z.

    2010-08-01

    In this paper, we firstly present a novel microscale-step structure fabricated by anodizing aluminum in a mixture of 0.05-0.5 wt% NaCl (HCl), 2 wt% H 3PO 4 and 20 wt% ethanol under potentials of 1-40 V at room temperature. Then, we present two micro-nano combined structures by integrating the microsteps with nanopores through multi-step anodizations. The microstep-nanopore hierarchical structure was obtained by re-anodizing the sample in oxalic acid, and the regular nanopores can be realized on the microscale patterned aluminum surface. The two-layer porous structure was one layer of nanoporous anodic alumina and another layer of micropores by two-step anodization on sample's both sides. These two novel structures can be useful for surface engineering and high flux filtration, respectively. The current fabrication approach broadens the applications of aluminum anodization, and brings a new method for assembling micro-nano structures.

  2. Preparation of granular activated carbons from yellow mombin fruit stones for CO2 adsorption.

    PubMed

    Fiuza, Raildo Alves; Medeiros de Jesus Neto, Raimundo; Correia, Laise Bacelar; Carvalho Andrade, Heloysa Martins

    2015-09-15

    Stones of yellow mombin, a native fruit of the tropical America and West Indies, were used as starting materials to produce activated carbons, subsequently used as adsorbent for CO2 capture. The carbonaceous materials were either chemically activated with HNO3, H3PO4 and KOH or physically activated with CO2. The carbon samples were characterized by SEM, EDX, TG/DTA, Raman spectroscopy, physical adsorption for textural analysis and by acid-base titrations. The CO2 adsorption capacity and adsorption cycles were investigated by TG. The results indicate that the capacity of CO2 adsorption may be maximized on highly basic surfaces of micropores smaller than 1 nm. The KOH activated carbon showed high and stable capacity of CO2 adsorption after 10 cycles. PMID:26182993

  3. Anodized titania: Processing and characterization to improve cell-materials interactions for load bearing implants

    NASA Astrophysics Data System (ADS)

    Das, Kakoli

    The objective of this study is to investigate in vitro cell-materials interactions using human osteoblast cells on anodized titanium. Titanium is a bioinert material and, therefore, gets encapsulated after implantation into the living body by a fibrous tissue that isolates them from the surrounding tissues. In this work, bioactive nonporous and nanoporous TiO2 layers were grown on commercially pure titanium substrate by anodization process using different electrolyte solutions namely (1) H3PO 4, (2) HF and (3) H2SO4, (4) aqueous solution of citric acid, sodium fluoride and sulfuric acid. The first three electrolytes produced bioactive TiO2 films with a nonporous structure showing three distinctive surface morphologies. Nanoporous morphology was obtained on Ti-surfaces from the fourth electrolyte at 20V for 4h. Cross-sectional view of the nanoporous surface reveals titania nanotubes of length 600 nm. It was found that increasing anodization time initially increased the height of the nanotubes while maintaining the tubular array structure, but beyond 4h, growth of nanotubes decreased with a collapsed array structure. Human osteoblast (HOB) cell attachment and growth behavior were studied using an osteoprecursor cell line (OPC 1) for 3, 7 and 11 days. Colonization of the cells was noticed with distinctive cell-to-cell attachment on HF anodized surfaces. TiO2 layer grown in H2SO4 electrolyte did not show significant cell growth on the surface, and some cell death was also noticed. Good cellular adherence with extracellular matrix extensions in between the cells was noticed for samples anodized with H3PO 4 electrolyte and nanotube surface. Cell proliferation was excellent on anodized nanotube surfaces. An abundant amount of extracellular matrix (ECM) between the neighboring cells was also noticed on nanotube surfaces with filopodia extensions coming out from cells to grasp the nanoporous surface for anchorage. To better understand and compare cell-materials interactions, anodized nanoporous sample surfaces were etched with different patterns. Preferential cell attachment was noticed on nanotube surfaces compared to no cells on etched patterned surface. Cell adhesions and differentiation were more pronounced with vinculin protein and alkaline phosphatase, respectively, on anodized surfaces. MTT assays showed increase in living cell density and higher proliferation on H3PO4, HF and nanotube surfaces. When anodized surfaces were compared for cell materials interaction, it was noticed that each of the surfaces has different surface properties that led to variations in cell-materials interactions. It was clear that rough surface morphology, high surface energy, and low value of the contact angles were important factors for better cell materials interaction. Mineralization study was done in simulated body fluid (SBF) with ion concentration nearly equal to human blood plasma to further understand biomimetic apatite deposition behavior. Similar to cell-materials interaction, variation in mineral deposition behavior was also noticed for films grown with different electrolytes. These results clearly show that nonporous titania in H3PO4, HF electrolytes and nanotubes can significantly increase biocompatibility of Ti implants, which has the potential to reduce the healing time and increase in vivo lifetime for these implants.

  4. Temperature dependence of the electrode kinetics of oxygen reduction at the platinum/Nafion interface - A microelectrode investigation

    NASA Technical Reports Server (NTRS)

    Parthasarathy, Arvind; Srinivasan, Supramanian; Appleby, A. J.; Martin, Charles R.

    1992-01-01

    Results of a study of the temperature dependence of the oxygen reduction kinetics at the Pt/Nafion interface are presented. This study was carried out in the temperature range of 30-80 C and at 5 atm of oxygen pressure. The results showed a linear increase of the Tafel slope with temperature in the low current density region, but the Tafel slope was found to be independent of temperature in the high current density region. The values of the activation energy for oxygen reduction at the platinum/Nafion interface are nearly the same as those obtained at the platinum/trifluoromethane sulfonic acid interface but less than values obtained at the Pt/H3PO4 and Pt/HClO4 interfaces. The diffusion coefficient of oxygen in Nafion increases with temperature while its solubility decreases with temperature. These temperatures also depend on the water content of the membrane.

  5. Preparation of bio-based porous carbon by microwave assisted phosphoric acid activation and its use for adsorption of Cr(VI).

    PubMed

    Gupta, Vinod Kumar; Pathania, Deepak; Sharma, Shikha; Singh, Pardeep

    2013-07-01

    Ficus carica fiber based activated carbon (FCAC) was used as a potential adsorbent for Cr(VI) removal from aqueous system. The adsorbent was prepared by carbonization of F. carica fiber followed by H3PO4 activation under microwave radiations. The activated carbon was characterized using scanning electron microscopy and Fourier transformer infrared spectroscopy. The adsorption data were well studied for adsorption isotherms, kinetics models, and thermodynamics. Adsorption of chromium ion followed the second-order kinetics and best fitted the Langmuir adsorption isotherms. The maximum adsorption capacity of Cr(VI) onto FCAC was 44.84 mg/g. The calculated values of thermodynamic parameters like enthalpy change (?H°), entropy change (?S°), and free energy change (?G°) were found to be 7.85 kJ/mol, 69.17 J/mol K, and -13.11 kJ/mol, respectively. Adsorption process was spontaneous and endothermic in nature. PMID:23611657

  6. CO2 Adsorption on Activated Carbon Honeycomb-Monoliths: A Comparison of Langmuir and Tóth Models

    PubMed Central

    Vargas, Diana P.; Giraldo, Liliana; Moreno-Piraján, Juan C.

    2012-01-01

    Activated carbon honeycomb-monoliths with different textural properties were prepared by chemical activation of African palm shells with H3PO4, ZnCl2 and CaCl2 aqueous solutions of various concentrations. The adsorbents obtained were characterized by N2 adsorption at 77 K, and their carbon dioxide adsorption capacities were measured at 273 K and 1 Bar in volumetric adsorption equipment. The experimental adsorption isotherms were fitted to Langmuir and Tóth models, and a better fit was observed to Tóth equation with a correlation coefficient of 0.999. The maximum experimental values for adsorption capacity at the highest pressure (2.627–5.756 mmol·g?1) are between the calculated data in the two models. PMID:22942710

  7. Ab initio calculations of proton transfer in dimethylformamide-phosphoric acid complexes of 1 : 1 composition

    NASA Astrophysics Data System (ADS)

    Krestyaninov, M. A.; Kiselev, M. G.; Safonova, L. P.

    2015-04-01

    The energy parameters of the reactions that result from adding protons to phosphoric acid, its dimer, and dimethylformamide; the reactions of the formation of phosphoric acid dimers and dimethylformamide-phosphoric acid complexes; and reactions involving the protonated forms of dimethylformamide and acid are calculated by means of DFT B3LYP using the 6-31++G( d, p) basis set. The structural characteristics of the complexes and transitional states are calculated along with the change in energy upon proton transfer. The effect media have on the energy characteristics of proton transfer is studied. It is found the energy barrier of proton transfer grows upon an increase in the O⋯O distance. It is concluded that the lowest energy barriers of proton transfer are expected for DMFH+⋯DMF and H3PO4⋯H2PO{4/-} complexes.

  8. Highly Flexible and Planar Supercapacitors Using Graphite Flakes/Polypyrrole in Polymer Lapping Film.

    PubMed

    Raj, C Justin; Kim, Byung Chul; Cho, Won-Je; Lee, Won-gil; Jung, Sang-Don; Kim, Yong Hee; Park, Sang Yeop; Yu, Kook Hyun

    2015-06-24

    Flexible supercapacitor electrodes have been fabricated by simple fabrication technique using graphite nanoflakes on polymer lapping films as flexible substrate. An additional thin layer of conducting polymer polypyrrole over the electrode improved the surface conductivity and exhibited excellent electrochemical performances. Such capacitor films showed better energy density and power density with a maximum capacitance value of 37 mF cm(-2) in a half cell configuration using 1 M H2SO4 electrolyte, 23 mF cm(-2) in full cell, and 6 mF cm(-2) as planar cell configuration using poly(vinyl alcohol) (PVA)/phosphoric acid (H3PO4) solid state electrolyte. Moreover, the graphite nanoflakes/polypyrrole over polymer lapping film demonstrated good flexibility and cyclic stability. PMID:26010272

  9. Redetermination of AgPO(3).

    PubMed

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ?). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure. PMID:21522230

  10. Redetermination of AgPO3

    PubMed Central

    Terebilenko, Katherina V.; Zatovsky, Igor V.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO3, were prepared via a phospho­ric acid melt method using a solution of Ag3PO4 in H3PO4. In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ?). Acta Cryst. 14, 779–784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO5] polyhedra, giving rise to multidirectional ribbons, and from two types of PO4 tetra­hedra linked into meandering chains (PO3)n spreading parallel to the b axis with a repeat unit of four tetra­hedra. The calculated bond-valence sum value of one of the two AgI ions indicates a significant strain of the structure. PMID:21522230

  11. Comparative study of mechanical, hydrothermal, chemical and enzymatic treatments of digested biofibers to improve biogas production.

    PubMed

    Bruni, Emiliano; Jensen, Anders Peter; Angelidaki, Irini

    2010-11-01

    Organic waste such as manure is an important resource for biogas production. The biodegradability of manures is however limited because of the recalcitrant nature of the biofibers it contains. To increase the biogas potential of the biofibers in digested manure, we investigated physical treatment (milling), chemical treatment (CaO), biological treatment (enzymatic and partial aerobic microbial conversion), steam treatment with catalyst (H(3)PO(4) or NaOH) and combination of biological and steam treatments (biofibers steam-treated with catalyst were treated with laccase enzyme). We obtained the highest methane yield increase through the chemical treatment that resulted in 66% higher methane production compared to untreated biofibers. The combination of steam treatment with NaOH and subsequent enzymatic treatment increased the methane yield by 34%. To choose the optimal treatment, the energy requirements relative to the energy gain as extra biogas production have to be taken into account, as well as the costs of chemicals or enzymes. PMID:20638274

  12. Performances of toluene removal by activated carbon derived from durian shell.

    PubMed

    Tham, Y J; Latif, Puziah Abdul; Abdullah, A M; Shamala-Devi, A; Taufiq-Yap, Y H

    2011-01-01

    In the effort to find alternative low cost adsorbent for volatile organic vapors has prompted this research in assessing the effectiveness of activated carbon produced from durian shell in removing toluene vapors. Durian shells were impregnated with different concentrations of H3PO4 followed by carbonization at 500 °C for 20 min under nitrogen atmosphere. The prepared durian shell activated carbon (DSAC) was characterized for its physical and chemical properties. The removal efficiency of toluene by DSAC was performed using different toluene concentrations. Results showed that the highest BET surface area of the produced DSAC was 1404 m2/g. Highest removal efficiency of toluene vapors was achieved by using DSAC impregnated with 30% of acid concentration heated at 500 °C for 20 min heating duration. However, there is insignificant difference between removal efficiency of toluene by DSAC and different toluene concentrations. The toluene adsorption by DSAC was better fitted into Freundlich model. PMID:20884200

  13. Development of value-added products from alumina industry mineral wastes using low-temperature-setting phosphate ceramics

    SciTech Connect

    Wagh, A.S.; Jeong, Seung-Young; Singh, D.

    1996-01-01

    A room-temperature process for stabilizing mineral waste streams has been developed, based on acid-base reaction between MgO and H3PO4 or acid phosphate solution. The resulting waste form sets into a hard ceramic in a few hours. In this way, various alumina industry wastes, such as red mud and treated potliner waste, can be solidified into ceramics which can be used as structural materials in waste management and construction industry. Red mud ceramics made by this process were low-porosity materials ({approx}2 vol%) with a compression strength equal to portland cement concrete (4944 psi). Bonding mechanism appears to be result of reactions of boehmite, goethite, and bayerite with the acid solution, and also encapsulation of red mud particles in Mg phosphate matrix. Possible applications include liners for ponds and thickned tailings disposal, dikes for waste ponds, and grouts. Compatability problems arising at the interface of the liner and the waste are avoided.

  14. Plasmonic silicon solar cell based on silver nanoparticles using ultra-thin anodic aluminum oxide template

    NASA Astrophysics Data System (ADS)

    Ho, Wen-Jeng; Cheng, Po-Yueh; Hsiao, Kuan-Yu

    2015-11-01

    This study fabricated a plasmonic silicon solar cell covered with silver (Ag) nanoparticles (NPs) using an ultra-thin anodic aluminum oxide (AAO) template as a deposition mask. An ultra-thin AAO template of approximately 200 nm was produced using a single-step anodization process in which an Al substrate was etched with phosphoric acid (H3PO4) for 3 min. We then used scanning electron microscopy (SEM) to examine the thickness and density of the AAO as a function of anodization duration, the results of which were confirmed by optical transmission measurement. The photovoltaic performance of the resulting silicon solar cell with Ag NPs was characterized according to photovoltaic current-voltage and external quantum efficiency. The inclusion of Ag NPs resulted in a 32.92% increase in conversion efficiency, compared with reference solar cells produced without Ag NPs.

  15. Speciation of arsenic in environmental samples of the Nha Trang Harbor, Vietnam, using HPLC coupled HG-AAS.

    PubMed

    Le, Lan Anh; Trinh, Anh Duc; Nguyen, Dinh Thuat; Bui, Minh Ly

    2011-04-01

    A coupled high performance liquid chromatography-hydride generation-atomic absorption spectroscopy system was used to determine the speciation of arsenic in samples from the Nha Trang Harbor, Vietnam. Concentrations of arsenic in seawater, pore water, suspended solid, and sediment were 4.12-9.81 ?g/L, 13.10-24.32 ?g/L, 1.87-6.42 ?g/g, and 3.37-9.06 ?g/g, respectively. Extraction using H(3)PO(4) + NH(2)OH·HCl and ultrasonic digestion was optimized to yield a 76-85% of total arsenic. Arsenic (III) was the most abundant species in suspended solids and sediments whereas arsenic (V) represented for 30-50% of arsenic (III) concentration. Monomethylarsonic acid and dimethylarsinic acid species were undetectable. PMID:21365299

  16. Influence of activated carbon upon the photocatalytic degradation of methylene blue under UV-vis irradiation.

    PubMed

    Matos, Juan; Montaña, Ricmary; Rivero, Eliram

    2015-01-01

    Photodegradation of methylene blue (MB) was studied on TiO2 in the presence of activated carbon (AC) prepared from the sawdust of a soft wood by physical activation under CO2 flow, by pyrolysis under N2 flow, and by chemical activation with ZnCl2 and H3PO4 under N2 flow. MB photodegradation was performed under UV and UV-visible irradiation to verify the scaling-up of the present TiO2-AC binary materials. It was verified that oxygenated surface groups on carbon were intrinsically photoactive, and a synergy effect between both solids has been estimated from the first-order apparent rate constants in the photodegradation of MB. This effect enhances the photoactivity of TiO2 up to a factor of about 9 under visible irradiation, and it was associated to the surface properties of AC. PMID:24788930

  17. Shallow Etching of GaAs/AlGaAs Heterostructures in Context of HEMT Fabrication

    NASA Astrophysics Data System (ADS)

    Kumar, Ch. Ravi; Rajaram, G.

    2011-07-01

    Gate recess etching is a key step in the fabrication process of high electron mobility transistors (HEMTs). The thin n+ cap layer needs to be etched without destroying the underlying supply layer. Conventional GaAs etch solutions based on H2SO4 or H3PO4 acids have high etch rates and hence present difficulties in the control of etch rates for shallow etches. Etches using Citric acid (CA) based solutions have been reported to have potential in such applications. Such etches with varying ratio of CA:H2O2:H2O are compared. A suitable recipe has been obtained for shallow gate recess etch and a HEMT is fabricated using the process.

  18. Effects of ultrasonic fields in the phosphoric acid process

    NASA Technical Reports Server (NTRS)

    Kowalska, E.; Mizera, J.; Jakobiec, H.

    1974-01-01

    A process of apatite decomposition with sulfuric acid was studied under the influence of ultrasound in the phosphoric acid production process. The studies were carried out with and without ultrasonic fields in the reaction mixture, which resembled the mixing ratio used in technical production processes. Ultrasound with a frequency of 20 kHz and an intensity of 1 W/sq cm was used in the studies. A very favorable ultrasonic effect upon the degree of apatite decomposition was observed. The ultrasonic field affects the shape of byproduct gypsum crystals. In the H3PO4 production process without ultrasound, the byproduct gypsum crystallizes as long, thin needles which cause problems in filtration. In the trials involving the application of wound, gypsum crystallized in the form of small platelets possessing a favorable ratio of length to width.

  19. Synthesis and structural characterisation using Rietveld and pair distribution function analysis of layered mixed titanium-zirconium phosphates

    NASA Astrophysics Data System (ADS)

    Burnell, Victoria A.; Readman, Jennifer E.; Tang, Chiu C.; Parker, Julia E.; Thompson, Stephen P.; Hriljac, Joseph A.

    2010-09-01

    Crystalline metal (IV) phosphates with variable zirconium-to-titanium molar ratios of general formula (Ti 1- xZr x)(HPO 4) 2·H 2O have been prepared by precipitation of soluble salts of the metals with phosphoric acid and heating the amorphous solids in 12 M H 3PO 4 in an autoclave. The new materials are structurally characterised by Rietveld analysis of synchrotron X-ray powder diffraction data and pair distribution function (PDF) analysis of high energy synchrotron X-ray total scattering data. A broad range of zirconium-titanium phosphate solid solutions were formed showing isomorphous substitution of titanium by zirconium in the ?-titanium phosphate lattice and vice versa for titanium substitution into the ?-zirconium phosphate lattice. In both cases the solubility is partial with the coexistence of two substituted phases observed in samples with nominal compositions between the solubility limits.

  20. Strongly reduced Si surface recombination by charge injection during etching in diluted HF/HNO3.

    PubMed

    Greil, Stefanie M; Schöpke, Andreas; Rappich, Jörg

    2012-08-27

    Herein, we investigate the behaviour of the surface recombination of light-induced charge carriers during the etching of Si in alkaline (KOH) and acidic etching solutions of HF/HNO(3)/CH(3)COOH (HNA) or HF/HNO(3)/H(3)PO(4) (HNP) at different concentration ratios of HF and HNO(3) by means of photoluminescence (PL) measurements. The surface recombination velocity is strongly reduced during the first stages of etching in HF/HNO(3)-containing solutions pointing to a interface well passivated by the etching process, where a positive surface charge is induced by hole injection from NO-related surface species into the Si near-surface region (back surface field effect). This injected charge leads to a change in band bending by about 150 mV that repulses the light-induced charge carriers from the surface and therefore enhances the photoluminescence intensity, since non-radiative surface recombination is reduced. PMID:22761060

  1. Fabrication of Monolithic Sapphire Membranes for High T(sub c) Bolometer Array Development

    NASA Technical Reports Server (NTRS)

    Pugel, D. E.; Lakew, B.; Aslam, S.; Wang, L.

    2004-01-01

    This paper examines the effectiveness of Pt/Cr thin film masks for the architecture of monolithic membrane structures in r-plane single crystal sapphire. The development of a pinhole-free Pt/Cr composite mask that is resistant to boiling H2SO4:H3PO4 etchant will lead to the fabrication of smooth sapphire membranes whose surfaces are well-suited for the growth of low-noise high Tc films. In particular, the relationship of thermal annealing conditions on the Pt/Cr composite mask system to: (1) changes in the surface morphology (2) elemental concentration of the Pt/Cr thin film layers and (3) etch pit formation on the sapphire surface will be presented.

  2. HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM- BASED SORBENTS. 2. EXPERIMENTAL DATA AND THEORETICAL MODEL PREDICTIONS

    EPA Science Inventory

    The fundamental processes for injection of CaCO3 and Ca(OH)2 for the removal of SO2 from combustion gases of coal-fired boilers are analyzed on the basis of experimental data and a comprehensive theoretical model. Sulfation data were obtained in a 30-kW isothermal gas-particle t...

  3. Zentrum f ur Technomathematik Fachbereich 3 --Mathematik und Informatik

    E-print Network

    Bremen, Universität

    places. But using such fine grid everywhere, the computation will get very slow, especially two and three everywhere, because slowly varying concentration fields can easily approximated a relatively coarse mesh carbonation concrete, involving the concentrations 1 c CO 2 and liquid phases, c Ca(OH) 2 water, and total

  4. Synthesis of a Se0 /Calcite Composite Using Hydrothermal

    E-print Network

    Montes-Hernandez, German

    Synthesis of a Se0 /Calcite Composite Using Hydrothermal Carbonation of Ca(OH)2 CoupledVised Manuscript ReceiVed April 4, 2008 ABSTRACT: Elemental selenium (Se0 )/calcite composites were synthesized) deposited on the calcite matrix. Conversely, under O2-rich conditions, the composite consisted rod

  5. FUNDAMENTAL STUDIES OF DRY INJECTION OF CALCIUM-BASED SORBENTS FOR S02 CONTROL IN UTILITY BOILERS

    EPA Science Inventory

    The report describes research to determine the mechanisms which limit the extent of reaction between SO2 and calcium-based sorbents (CaCO3 and Ca(OH)2) by measuring the in situ physical structure and reactivity of sorbent injected into a combustion environment for residence times...

  6. Interactive Effects of Soil ph, Halosulfuron Rate, and Application Method on Carryover to Turnip Green and Cabbage.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted in 2006 and 2007 to evaluate the tolerance of autumn-planted cabbage and turnip green to halosulfuron applied the previous spring to cantaloupe. Main plots were three levels of soil pH; maintained at a natural pH level, pH raised with Ca(OH)2, and pH lowered with Al2(SO...

  7. Impact of mitigation strategies on acid sulfate soil chemistry and microbial community.

    PubMed

    Wu, Xiaofen; Sten, Pekka; Engblom, Sten; Nowak, Pawel; Österholm, Peter; Dopson, Mark

    2015-09-01

    Potential acid sulfate soils contain reduced iron sulfides that if oxidized, can cause significant environmental damage by releasing large amounts of acid and metals. This study examines metal and acid release as well as the microbial community capable of catalyzing metal sulfide oxidation after treating acid sulfate soil with calcium carbonate (CaCO3) or calcium hydroxide (Ca(OH)2). Leaching tests of acid sulfate soil samples were carried out in the laboratory. The pH of the leachate during the initial flushing with water lay between 3.8 and 4.4 suggesting that the jarosite/schwertmannite equilibrium controls the solution chemistry. However, the pH increased to circa 6 after treatment with CaCO3 suspension and circa 12 after introducing Ca(OH)2 solution. 16S rRNA gene sequences amplified from community DNA extracted from the untreated and both CaCO3 and Ca(OH)2 treated acid sulfate soils were most similar to bacteria (69.1% to 85.7%) and archaea (95.4% to 100%) previously identified from acid and metal contaminated environments. These species included a Thiomonas cuprina-like and an Acidocella-like bacteria as well as a Ferroplasma acidiphilum-like archeon. Although the CaCO3 and Ca(OH)2 treatments did not decrease the proportion of microorganisms capable of accelerating acid and metal release, the chemical effects of the treatments suggested their reduced activity. PMID:25933291

  8. Dentinal tubule disinfection with 2% chlorhexidine, garlic extract, and calcium hydroxide against Enterococcus faecalis by using real-time polymerase chain reaction: In vitro study

    PubMed Central

    Eswar, Kandaswamy; Venkateshbabu, Nagendrababu; Rajeswari, Kalaiselvam; Kandaswamy, Deivanayagam

    2013-01-01

    Aim: To compare the efficacy of garlic extract with 2% chlorhexidine (CHX) and calcium hydroxide Ca(OH)2 in disinfection of dentinal tubules contaminated with Enterococcus faecalis by using real-time polymerase chain reaction (PCR). Materials and Methods: Agar diffusion test was done to evaluate the minimum inhibitory concentration of garlic extract against E. faecalis. Forty human extracted mandibular premolar teeth were selected for this study, access cavity was prepared and cleaning and shaping was done. Middle third of the root was cut using a rotary diamond disc. The teeth specimens were inoculated with E. faecalis for 21 days. Specimens were divided into four groups---Group 1: 2% CHX, Group 2: Garlic extract, Group 3: Ca(OH)2, and Group 4: Saline (negative control). The intracanal medicaments were packed inside the tooth specimens and incubated for 5 days. The dentinal chips were collected at 400 ?m depth using a Gates-Glidden drill, following which DNA isolation was done. The specimens were analyzed using real-time PCR. The results were then statistically analyzed using one-way analysis of variance, followed by post hoc Tukey's honestly significant difference (HSD) multiple comparison of means. Results: Threshold cycle (Ct) values of 2% CHX was found to be 32.4, garlic extract to be 27.5, and Ca(OH)2 to be 25.6. Conclusion: A total of 2% CHX showed the maximum efficacy against E. faecalis, followed by garlic extract and Ca(OH)2. PMID:23833449

  9. REACTION MECHANISMS OF DRY CA-BASED SORBENTS WITH GASEOUS HCL

    EPA Science Inventory

    The paper discusses an investigation of the mechanisms of HCl reaction with dry Ca(OH)2 or CaO sorbents in flue gas cleaning applications using differential scanning calorimetry (DSC), thermogravimetry (TGA), and X-ray diffraction (XRD). hort-time differential reactor (STDR) was ...

  10. Characterisation of the efficacy of endodontic medications using a three-dimensional fluorescent tooth model: An ex vivo study.

    PubMed

    Chen, Emily W; Carey, Alison J; Ulett, Glen C; George, Roy

    2015-08-01

    The purpose of this study was to establish a three-dimensional fluorescent tooth model to investigate bacterial viability against intra-canal medicaments across the thickness and surface of root dentine. Dental microbial biofilms (Enterococcus faecalis and Streptococcus mutans) were established on the external root surface and bacterial kill was monitored over time against intra-canal medicament (Ca(OH)2 ) using fluorescent microscopy in conjunction with BacLight SYTO9 and propidium iodide stains. An Olympus digital camera fitted to SZX16 fluorescent microscope captured images of bacterial cells in biofilms on the external root surface. Viability of biofilm was measured by calculating the total pixel area of green (viable bacteria) and red (non-viable bacteria) for each image using ImageJ® software. All data generated were assessed for normality and then analysed using a Mann-Whitney t-test. The viability of S.?mutans biofilm following Ca(OH)2 treatment showed a significant decline compared with the untreated group (P?=?0.0418). No significant difference was seen for E.?faecalis biofilm between the Ca(OH)2 and untreated groups indicating Ca(OH)2 medicament is ineffective against E.?faecalis biofilm. This novel three-dimensional fluorescent biofilm model provides a new clinically relevant tool for testing of medicaments against dental biofilms. PMID:25583457

  11. INVESTIGATION OF PRODUCT-LAYER DIFFUSIVITY FOR CAO SULFATION

    EPA Science Inventory

    The paper gives results of comparisons of the sulfation rates of CaO prepared from Ca(OH)2 and CaCO3, using six types of each precursor derived from the same natural limestones. The particles were small enough to eliminate all transport resistances except diffusion through the Ca...

  12. EFFECT OF RELATIVE HUMIDITY AND ADDITIVES ON THE REACTION OF SULFUR DIOXIDE WITH CALCIUM HYDROXIDE

    EPA Science Inventory

    The paper gives results of a study of the reaction of SO2 with Ca(OH)2 at conditions similar to those of commercial-scale bag filters: 19-74 percent relative humidity (RH), 30.4-95 C, and 300-4000 ppm SO2. The study was carried out in a bench-scale reactor with powder reagent Ca(...

  13. CALCIUM OXIDE SINTERING IN ATMOSPHERES CONTAINING WATER AND CARBON DIOXIDE

    EPA Science Inventory

    The paper gives results of measurements of the effects of water vapor and CO2 on the sintering rate of nascent CaO, as a function of partial pressure and temperature using CaO prepared by rapid decomposition of CaCO3 and CA(OH)2. Each gas strongly catalyzed the sintering process ...

  14. A Simple Recipe for Whitening Old Newspaper Clippings.

    ERIC Educational Resources Information Center

    Carter, Henry A.

    1995-01-01

    Describes a method for experimenting with both whitening and deacidifying old newspaper clippings using sodium borohydride bleaching. Clippings are soaked in distilled water then immersed in sodium borohydride for 15-20 minutes. After rinsing with distilled water, the paper is washed with saturated Ca(OH)2 solution. Readers should not begin…

  15. DNAPL source control by reductive dechlorination with iron-based degradative solidification/stabilization 

    E-print Network

    Do, Si Hyun

    2009-05-15

    by compounds that are formed by reaction of ferrous iron with components of Portland cement or with defined chemicals (FeCl3 + Ca(OH)2). These dechlorinating agents can effectively degrade chlorinated hydrocarbons (PCE, TCE, and 1,1,1-TCA) that are dissolved...

  16. HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM- BASED SORBENTS. 1. THEORETICAL SULFATION MODEL

    EPA Science Inventory

    A mathematical model for the sulfation of CaO is developed around the overlapping grain concept. The potential influence of high mass-transfer rates from simultaneous calcination of CaCO3 or Ca(OH)2 is incorporated in the mass-transfer coefficient for SO2 diffusion to the partic...

  17. Effectiveness of a new canal brushing technique in removing calcium hydroxide from the root canal system: A scanning electron microscope study

    PubMed Central

    Gorduysus, Melahat; Yilmaz, Zeliha; Gorduysus, Omer; Atila, Burcu; Karapinar, Senem Oransal

    2012-01-01

    Aim: To evaluate the effectiveness of Canal Brush technique removal Ca(OH)2 from the root canal system using Scanning Electron Microscope (SEM). Materials and Methods: Eighteen teeth were instrumented up to #40 and dressed with Ca(OH)2. Ca(OH)2 was removed with master apical file (MAF) (Group 1, n:6) and CanalBrush technique (Group 2, n:6). Six teeth served as positive and negative controls. The roots were splited in the buccolingual direction and prepared for SEM examination. Two examiners evaluated the wall cleanliness then statistical analysis was performed by Mann-Whitney U and Friedman tests. Results: Differences in cleanliness were observed between Group 1 and Group 2 in the apical thirds (P=0.002). In the coronal and middle thirds, there were no differences between the two groups. Conclusions: It is essential to re-instrument the root canal walls using instrumentation techniques while irrigating with NaOCl and EDTA combination. The Canal Brush technique results in the packing effect of the Ca(OH)2 through to the apex. PMID:23112486

  18. CALCINATION AND SINTERING MODELS FOR APPLICATION TO HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM-BASED SORBENTS

    EPA Science Inventory

    To simulate the staged availability of transient high surface area CaO observed in high-temperature flow-reactor data, the rate of calcination of CaCO3 or Ca(OH)2 is described by an empirical modification of the shrinking-core model. The physical model depicts particle decomposi...

  19. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    NASA Astrophysics Data System (ADS)

    Pretel, H.; Oliveira, J. A.; Lizarelli, R. F. Z.; Ramalho, L. T. O.

    2009-02-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI - only Ca(OH)2, GII - laser 688 nm, and GIII - laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p < 0.05) and between groups GI and GIII (p < 0.01). On 60th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm.

  20. ENHANCEMENT OF REACTIVITY IN SURFACTANT-MODIFIED SORBENTS FOR SULFUR DIOXIDE CONTROL

    EPA Science Inventory

    The paper discusses the enhancement of reactivity in surfactant-modified sorbents for S02 control. Injecting calcium-based sorbents into the post-flame zone of utility boilers can achieve S02 captures of 50-60% at a stoichiometry of 2. Calcium hydroxide-- Ca(OH)2--appears to be t...

  1. STRUCTURAL CHANGES IN SURFACTANT-MODIFIED SORBENTS DURING FURNACE INJECTION

    EPA Science Inventory

    A calcium hydroxide [Ca(OH)2] sorbent modified by the addition of calcium lignosulfonate has recently been developed for use in the Environmental Protection Agency's limestone injection multistage burner process. The increased reactivity with sulfur dioxide (SO2) displayed by thi...

  2. ENHANCEMENT OF REACTIVITY IN SURFACTANT-MODIFIED SORBENTS FOR SULFUR DIOXIDE CONTROL

    EPA Science Inventory

    Injection of calcium-based sorbents into the postflame zone of utility boilers is capable of achieving sulfur dioxide (SO2) captures of 50-60% at a stoichiometry of 2. Calcium hydroxide [Ca(OH)2] appears to be the most effective commercially available sorbent. Recent attempts to ...

  3. SOX OUT ON A LIMB (LIMESTONE INJECTION MULTISTAGE BURNER)

    EPA Science Inventory

    The paper describes the most recent results from the Limestone Injection Multistage Burner (LIMB) program, covering results from the wall-fired demonstration. Tests were conducted to determine the efficacy of commercial calcium hydroxide (Ca(OH)2) and of calcium-lignosulfonate-mo...

  4. ACTIVATION AND REACTIVITY OF NOVEL CALCIUM-BASED SORBENTS FOR DRY SO2 CONTROL IN BOILERS

    EPA Science Inventory

    Chemically modified calcium hydroxide (Ca(OH)2) sorbents developed in the U.S. Environmental Protection Agency's Air and Energy Engineering Research Laboratory (AEERL) for sulfur dioxide (SO2) control in utility boilers were tested in an electrically heated, bench-scale isotherma...

  5. LIGNOSULFONATE-MODIFIED CALCIUM HYDROXIDE FOR SULFUR DIOXIDE CONTROL

    EPA Science Inventory

    The article discusses the use of lignosulfonate-modified calcium hydroxide Ca(OH)2 for sulfur dioxide (SO2) control. The limestone injection multistage burner (LIMB) process is currently being developed at the U.S. EPA as a low cost retrofittable technology for controlling oxides...

  6. Thiocyanate, calcium and sulfate as causes of toxicity to Ceriodaphnia dubia in a hard rock mining effluent

    E-print Network

    Grosell, Martin

    , the mine utilizes a lime (Ca(OH)2) treatment plant for the removal of heavy metal contamination in the tailings impoundment water. The treatment plant removes the dissolved metals from solution and replaces. Toxicity identification evaluations are a series of experimental manipulations used to either remove

  7. Nutrient Availability from Douglas Fir Bark in Response to Substrate pH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two studies were conducted to determine the influence of substrate pH on nutrient availability in douglas fir bark (DFB). Douglas fir bark was amended with either calcium carbonate (CaCO3) or calcium hydroxide [Ca(OH)2] at 13 rates to generate substrates with low to high pH. A non-amended control ...

  8. SUMMARY REPORT: SULFUR OXIDES CONTROL TECHNOLOGY SERIES: FLUE GAS DESULFURIZATION - SPRAY DRYER PROCESS

    EPA Science Inventory

    Described spray dryer flue gas desulfurization (FGD), which is a throwaway process in which sulfur dioxide (SO2) is removed from flue gas by an atomized lime slurry [Ca(OH)2]. he hot flue gas dries the droplets to form a dry waste product, while the absorbent reacts with sulfur d...

  9. FURNACE SORBENT REACTIVITY TESTING FOR CONTROL OF SO2 EMISSIONS FROM ILLINOIS COALS

    EPA Science Inventory

    Research was undertaken to evaluate the potential of furnai sorbent injection (FSI) for sulf dioxide (S02) emission controlcoal-fired boilers utilizing coals indigenous to Illinois. Tests were run using four coals from the Illinois Basin and six calcium hydroxide [Ca(OH)2], sorbe...

  10. THE CHARACTERIZATION OF A SOLID SORBENT WITH CRYSTALLITE SIZE AND STRAIN DATA FROM X-RAY DIFFRACTION LINE BROADENING

    EPA Science Inventory

    The paper gives results of the characterization of a solid sorbent with crystallite size and strain data from x-ray diffraction line broadening, as part of an EPA investigation of the injection of dry Ca(OH)2 into coal-fired electric power plant burners for the control of SO2 emi...

  11. CALCINATION OF CALCIUM HYDROXIDE SORBENT IN THE PRESENCE OF SO2 AND ITS EFFECT ON REACTIVITY

    EPA Science Inventory

    The paper discusses the calcination of Ca(OH)2 sorbent in the presence of SO2 and its effect on reactivity. When Ca(0H)2 is calcined in an isothermal flow reactor with 300 ppm or less SO2, the structure of the sorbent is characterized by retention of higher pore volumes and surfa...

  12. Boosting Proton Conductivity in Highly Robust 3D Inorganic Cationic Extended Frameworks through Ion Exchange with Dihydrogen Phosphate Anions.

    PubMed

    Xiao, Chengliang; Wang, Yaxing; Chen, Lanhua; Yin, Xuemiao; Shu, Jie; Sheng, Daopeng; Chai, Zhifang; Albrecht-Schmitt, Thomas E; Wang, Shuao

    2015-12-01

    The limited long-term hydrolytic stability of rapidly emerging 3D-extended framework materials (MOFs, COFs, MOPs, etc.) is still one of major barriers for their practical applications as new solid-state electrolytes in fuel cells. To obtain hydrolytically stable materials, two H2 PO4 (-) -exchanged 3D inorganic cationic extended frameworks (CEFs) were successfully prepared by a facile anion-exchange method. Both anion-exchanged CEFs (YbO(OH)P and NDTBP) show significantly enhanced proton conductivity when compared with the original materials (YbO(OH)Cl and NDTB) with an increase of up to four orders-of-magnitude, reaching 2.36×10(-3) and 1.96×10(-2) ?S?cm(-1) at 98?% RH and 85?°C for YbO(OH)P and NDTBP, respectively. These values are comparable to the most efficient proton-conducting MOFs. In addition, these two anion-exchanged materials are stable in boiling water, which originates from the strong electrostatic interaction between the H2 PO4 (-) anion and the cationic host framework, showing a clear advance over all the acid-impregnated materials (H2 SO4 @MIL-101, H3 PO4 @MIL-101, and H3 PO4 @Tp-Azo) as practical solid-state fuel-cell electrolytes. This work offers a new general and efficient approach to functionalize 3D-extended frameworks through an anion-exchange process and achieves water-stability with ultra-high proton conductivity above 10(-2) ?S?cm(-1) . PMID:26489981

  13. Water extractable organic carbon in untreated and chemical treated biochars.

    PubMed

    Lin, Yun; Munroe, Paul; Joseph, Stephen; Henderson, Rita; Ziolkowski, Artur

    2012-04-01

    Biochar, as a soil amendment, can increase concentrations of soil organic matter, especially water-extractable organic carbon (WEOC). This can affect the adsorption-desorption equilibrium between the dissolved solid phases in soil organic matter. Dissolved organic carbon (DOC) represents a small proportion of soil organic matter, but is of significant importance in the soil ecosystem due to its mobility and reactivity. Here, water extracts obtained from twelve non-herbaceous biochars (before, and after, chemical treatment with either H(3)PO(4) or KOH), were tested by Liquid Chromatography - Organic Carbon Detection (LC-OCD) to identify the effects of both pyrolysis conditions and chemical treatments on WEOC content. LC-OCD has the capacity to provide a fingerprint of WEOC, which allows analysis of the various fractions present. WEOC content was affected by both the pyrolysis temperature and the feedstock used. High mineral ash contents deriving from the feedstock can prompt thermochemical reactions of lignocelluloses to produce a relatively high WEOC content, which includes low molecular weight neutrals and humic acids as dominant components. A significant change in WEOC occurred during pyrolysis due to secondary reactions which resulted in a much lower WEOC in the high temperature biochars where fractions of low molecular weight acids and neutrals are dominant. Chemical treatments with H(3)PO(4) or KOH increased WEOC concentration, possibly by promoting hydrolysis reactions on biochar surfaces. These observations assist in assessing the contribution of biochar additions to the soil ecosystem and demonstrate the utility of LC-OCD in providing an understanding of how biochar additions to soil can alter DOC. PMID:22236590

  14. Mechanism of Efficient Proton Conduction in Diphosphoric Acid Elucidated via First-Principles Simulation and NMR.

    PubMed

    Krueger, Rachel A; Vil?iauskas, Linas; Melchior, Jan-Patrick; Bester, Gabriel; Kreuer, Klaus-Dieter

    2015-12-31

    Diphosphoric acid (H4P2O7) is the first condensation product of phosphoric acid (H3PO4), the compound with the highest intrinsic proton conductivity in the liquid state. It exists at higher temperature (T > 200 °C) and lower relative humidity (RH ? 0.01%) and shows significant ionic conductivity under these conditions. In this work, ab initio molecular dynamics simulations of a pure H4P2O7 model system and NMR spectroscopy on nominal H4P2O7 (which contains significant amounts of ortho- and triphosphoric acid in thermodynamic equilibrium) were performed to reveal the nature and underlying mechanisms of the ionic conductivity. The central oxygen of the molecule is found to be excluded from any hydrogen bonding, which has two interesting consequences: (i) compared to H3PO4, the acidity of H4P2O7 is severely increased, and (ii) the condensation reaction only leads to a minor decrease in hydrogen bond network frustration, which is thought to be one of the features enabling high proton conductivity. A topological analysis of diphosphoric acid's hydrogen bond network shows remarkable similarities to that of phosphonic acid (H3PO3). The hydrogen bonding facilitates protonic polarization fluctuations (Zundel polarization) extending over several molecules (Grotthuss chains), the other important ingredient for efficient structural diffusion of protons. At T = 160 °C, this is estimated to make a conductivity contribution of about 0.1 S/cm, which accounts for half of the total ionic conductivity (? ? 0.2 S/cm). The other half is suggested to result from diffusion of charged phosphate species (vehicle mechanism) that are present in high concentration, resembling conduction in ionic liquids. PMID:26633234

  15. Influence of surface treatments on bond strength of metal and ceramic brackets to a novel CAD/CAM hybrid ceramic material.

    PubMed

    Elsaka, Shaymaa E

    2016-01-01

    This study evaluated the effect of four different surface treatments methods on the shear bond strength (SBS) of ceramic and metal brackets to Vita Enamic (VE) CAD/CAM hybrid ceramic. A total of 240 plates (10 mm × 10 mm × 3 mm) were cut from VE ceramic blocks and divided into two groups. In each group, four subgroups were prepared by hydrofluoric acid (HF); phosphoric acid (H3PO4); diamond ceramic grinding bur; and silica coating using CoJet system (CJ). Maxillary central incisor metal (Victory Series) and ceramic (Clarity) brackets were bonded with light-cure composite and then stored in artificial saliva for 1 week and thermocycled. The SBS test was performed, and the failure types were classified with adhesive remnant index scores. Surface morphology of the ceramic was characterized after treatment using a scanning electron microscope. Data were analyzed using two-way ANOVA, Tukey HSD test, and Weibull analysis. SBS was significantly affected by the type of bracket and by type of treatment (P < 0.001). Specimens treated with CJ presented with significantly higher SBS compared to other groups (P < 0.05). Improvements in SBS values (MPa) were found in the following order: CJ > HF > Bur > H3PO4. Ceramic bracket showed higher SBS compared to metal bracket. Adhesive failures between the ceramic and composite resin were the predominant mode of failure in all groups. Surface treatment of VE CAD/CAM hybrid ceramic with silica coating enhanced the adhesion with ceramic and metal brackets. PMID:25585677

  16. Influence of different acid and alkaline cleaning agents on the effects of irrigation of synthetic dairy factory effluent on soil quality, ryegrass growth and nutrient uptake.

    PubMed

    Liu, Y-Y; Haynes, R J

    2013-01-01

    The aim of this study was to examine the effects of replacement of phosphoric acid with nitric or acetic acid, and replacement of NaOH with KOH, as cleaning agents in dairy factories, on the effects that irrigation of dairy factory effluent (DFE) has on the soil-plant system. A 16-week greenhouse study was carried out in which the effects of addition of synthetic dairy factory effluent containing (a) milk residues alone or milk residues plus (b) H(3)PO(4)/NaOH, (c) H(3)PO(4)/HNO(3)/NaOH or (d) CH(3)COOH/KOH, on soil's chemical, physical and microbial properties and perennial ryegrass growth and nutrient uptake were investigated. The cumulative effect of DFE addition was to increase exchangeable Na, K, Ca, Mg, exchangeable sodium percentage, microbial biomass C and N and basal respiration in the soil. Dry matter yields of ryegrass were increased by additions of DFE other than that containing CH(3)COOH. Plant uptake of P, Ca and Mg was in the same order as their inputs in DFE but for Na; inputs were an order of magnitude greater than plant uptake. Replacement of NaOH by KOH resulted in increased accumulation of exchangeable K. The effects of added NaOH and KOH on promoting breakdown of soil aggregates during wet sieving (and formation of a < 0.25 mm size class) were similar. Replacement of H(2)PO(4) by HNO(3) is a viable but CH(3)COOH appears to have detrimental effects on plant growth. Replacement of NaOH by KOH lowers the likelihood of phytotoxic effects of Na, but K and Na have similar effects on disaggregation. PMID:22707204

  17. Bismuth oxide nanotubes-graphene fiber-based flexible supercapacitors

    NASA Astrophysics Data System (ADS)

    Gopalsamy, Karthikeyan; Xu, Zhen; Zheng, Bingna; Huang, Tieqi; Kou, Liang; Zhao, Xiaoli; Gao, Chao

    2014-07-01

    Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics.Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics. Electronic supplementary information (ESI) available: Equations and characterization. SEM images of GGO, XRD and XPS of Bi2O3 NTs, HRTEM images and EDX Spectra of Bi2O3 NT5-GF, CV curves of Bi2O3NT5-GF, Bi2O3 NTs and bismuth nitrate in three-electrode system (vs. Ag/AgCl). CV and GCD curves of Bi2O3 NT1-GF and Bi2O3 NT3-GF. See DOI: 10.1039/c4nr02615b

  18. Organometallic catalysts for primary phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Walsh, Fraser

    1987-01-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  19. Scalable synthesis of hierarchically structured carbon nanotube-graphene fibres for capacitive energy storage

    NASA Astrophysics Data System (ADS)

    Yu, Dingshan; Goh, Kunli; Wang, Hong; Wei, Li; Jiang, Wenchao; Zhang, Qiang; Dai, Liming; Chen, Yuan

    2014-07-01

    Micro-supercapacitors are promising energy storage devices that can complement or even replace batteries in miniaturized portable electronics and microelectromechanical systems. Their main limitation, however, is the low volumetric energy density when compared with batteries. Here, we describe a hierarchically structured carbon microfibre made of an interconnected network of aligned single-walled carbon nanotubes with interposed nitrogen-doped reduced graphene oxide sheets. The nanomaterials form mesoporous structures of large specific surface area (396 m2 g-1) and high electrical conductivity (102 S cm-1). We develop a scalable method to continuously produce the fibres using a silica capillary column functioning as a hydrothermal microreactor. The resultant fibres show a specific volumetric capacity as high as 305 F cm-3 in sulphuric acid (measured at 73.5 mA cm-3 in a three-electrode cell) or 300 F cm-3 in polyvinyl alcohol (PVA)/H3PO4 electrolyte (measured at 26.7 mA cm-3 in a two-electrode cell). A full micro-supercapacitor with PVA/H3PO4 gel electrolyte, free from binder, current collector and separator, has a volumetric energy density of ~6.3 mWh cm-3 (a value comparable to that of 4 V-500 µAh thin-film lithium batteries) while maintaining a power density more than two orders of magnitude higher than that of batteries, as well as a long cycle life. To demonstrate that our fibre-based, all-solid-state micro-supercapacitors can be easily integrated into miniaturized flexible devices, we use them to power an ultraviolet photodetector and a light-emitting diode.

  20. Management of Post-orthodontic White Spot Lesions and Subsequent Enamel Discoloration with Two Microabrasion Techniques

    PubMed Central

    Jahanbin, Arezoo; Ameri, Hamideh; Shahabi, Mostafa; Ghazi, Ala

    2015-01-01

    Statement of the Problem Demineralization of enamel adjacent to orthodontic appliances frequently occurs, commonly due to insufficient oral hygiene. Purpose The aim of this study was to compare two microabrasion techniques on improving the white spot lesions as well as subsequent enamel discoloration. Materials and Method Sixty extracted premolar teeth without caries and hypoplasia were selected for this study. White spot lesions were artificially induced on the buccal surface of each tooth. Teeth were randomly assigned to three treatment groups, each treated with pumice powder as the control, microabrasion with 18% HCl, and microabrasion with 37% H3PO4. Subsequently, the three groups were daily immersed for five minutes in a tea-coffee solution for a period of one week. Colorimetric evaluation was done before and after formation of white spot lesions, after microabrasion, and after immersion in the colored solution; then the color differences (?E) were calculated. Statistical analysis was performed by multiple measurement analysis and the Tukey’s test. Results This study showed that ?E between the stages of white spot formation and microabrasion for H3PO4 was more than other groups and for the pumice powder group it was less than the others. Furthermore, there was a significant difference between ?E of the three study groups (p= 0.017). Additionally, ?E after placing the teeth in the colored solution and microabrasion was the highest for the HCl group and the lowest for the pumice powder group. There was also a significant difference between the three groups (p= 0.000). Conclusion Pumice powder alone had similar effects as 18% HCl on removing the white spot lesions. Nevertheless, 18% HCl makes the enamel susceptible for subsequent color staining more than the other microabrasion methods. PMID:26106636

  1. Prevention of hydrolysable tannin toxicity in goats fed Clidemia hirta by calcium hydroxide supplementation.

    PubMed

    Murdiati, T B; McSweeney, C S; Campbell, R S; Stoltz, D S

    1990-10-01

    Although plants containing hydrolysable tannins can be hepatotoxic, such poisoning has not been reported in Indonesia despite the presence of these plants. In order to determine the hepatotoxic potential of Indonesian plants, goats were intoxicated experimentally with the Indonesian plant Climedia hirta (harendong), which contained 19% hydrolysable tannin. The prophylactic effect of Ca(OH)2 supplementation on the disease was also examined. Two groups of goats were fed for 28 days with grain-based pellets containing 50% harendong leaf or 50% harendong leaf + 8% Ca(OH)2. Two control groups were fed similar pellets containing 50% of the non-toxic elephant grass (Pennisetum purpureum) with and without 8% Ca(OH)2. Serum enzymes indicative of liver damage were monitored during the experiment and histopathological examination of selected tissues was done at the conclusion of the experiment. In goats given unsupplemented harendong pellets there was a significant increase in aspartate aminotransferase and glutamate dehydrogenase from 50.2 and 20.6 U l-1 to 219.6 and 63.3 U l-1, respectively. These changes were associated with moderate to severe nuclear plemorphism, vacuolation and megalocytosis of hepatocytes and deposits of brown pigment in the Kupffer cells. There was also nephrosis of the renal convoluted tubules and collecting ducts, abomasitis and enteritis. Biochemical and histological changes were reduced significantly in the harendong + Ca(OH)2 group and virtually absent from control groups. It is concluded that hydrolysable tannins in harendong leaf are hepato- and nephrotoxic and associated with gastroenteritis, but that poisoning may be ameliorated by Ca(OH)2 supplementation. PMID:2254583

  2. A Comparative Analysis of Antimicrobial Property of Wine and Ozone with Calcium Hydroxide and Chlorhexidine

    PubMed Central

    Ebenezar, A. V. Rajesh; Anand, Nirupa; Mary, A.Vinita; Mony, Bejoy

    2015-01-01

    Background The antibacterial properties of wine and ozone have been established but their antibacterial efficacies against endodontic pathogens are yet to be ascertained. Aim The purpose of this study is to comparatively evaluate the antibacterial property of ozonated water, white wine (14%) and de-alcoholised white wine. Materials and Methods S.mutans and E.faecalis were subcultured and inoculated in a nutrient broth for 24 hours. The following groups were formulated: Group 1A:2% Chlorhexidine (Control group); Group 1B:White wine; Group 1C:Dealcoholised white wine; Group 1D:Ozonated water; Group 2A: Ca(OH)2 + Chlorhexidine (Control group); Group 2B: White wine + Ca(OH)2; Group 2C:De-alcoholised White wine + Ca(OH)2 + chlorhexidine; Group 2D:White wine + Ca(OH)2 + chlorhexidine and group 2E: Dealcoholised white wine + Ca(OH)2 + chlorhexidine. The samples were allowed to diffuse into the culture medium for two hours, later the S. mutans were streaked on to the blood agar medium and the E. faecalis were streaked on to the Muller Hilton agar medium and incubated for 48 hours at 370C the zone of inhibition was measured after 48 hours. Results There was no growth of microorganisms seen with ozonated water. Chlorhexidine showed large zone of inhibition compared to the other groups. White wine has better antimicrobial property than de-alcoholised white wine, but when mixed with calcium hydroxide the dealcoholised white wine has better action against the microorganisms. Conclusion Ozonated water has the best antibacterial property and the antibacterial action of Calcium hydroxide is enhanced when it is mixed with de-alcoholised white wine. PMID:26266206

  3. Scanning electron microscopy evaluation of the hard tissue barrier after pulp capping with calcium hydroxide, mineral trioxide aggregate (MTA) or ProRoot MTA.

    PubMed

    Reston, Eduardo Galia; de Souza Costa, Carlos Alberto

    2009-08-01

    The aim of this study was to investigate the morphology and localisation of calcium hydroxide- and mineral trioxide aggregate (MTA)-induced hard tissue barriers after pulpotomy in dogs' teeth. Pulpotomies were performed on maxillary and mandibular premolars of five dogs. The teeth were assigned into three groups according to the pulp-capping agent used. The pulpal wounds were capped with calcium hydroxide (Ca(OH)(2)- control), MTA or ProRoot MTA, and the cavities were restored with amalgam. After a 90-day follow-up period, the dogs were euthanised and the teeth were examined under scanning electron microscopy (SEM). An image-processing and analysis software was used to delimit the perimeters of the root canal area and the hard tissue barrier to determine the percentage of root canal obliteration. SEM data were used to assess the morphology, localisation and extension of the reparative hard tissue barriers. ProRoot MTA was statistically different from MTA and Ca(OH)(2) (P < 0.05) regarding tissue barrier morphology. Localisation data showed that ProRoot MTA was significantly different from Ca(OH)(2) (P < 0.05) and similar to MTA (P > 0.01; P > 0.05). No statistically significant difference (P > 0.01; P > 0.05) was observed between MTA and Ca(OH)(2). A larger number of complete (centroperipheral) hard tissue barriers with predominance of dentinal tubules was observed to the ProRoot MTA when compared with the Ca(OH)(2) group. PMID:19703080

  4. Improved efficiency of separate hexose and pentose fermentation from steam-exploded corn stalk for butanol production using Clostridium beijerinckii.

    PubMed

    Mu, Xindong; Sun, Wei; Liu, Chao; Wang, Haisong

    2011-08-01

    Water extract of steam-exploded corn stalk (SECS) was detoxified and used as feed for acetone-butanol-ethanol (ABE) fermentation using Clostridium beijerinckii. Utilization of water extract improved the total ABE yield (g ABE/g dry SECS). Separated fermentation showed higher fermentability (0.078 g ABE/g dry SECS) over typical fermentation (0.058 g ABE/g dry SECS). Furthermore, the final ABE yields (g ABE/g utilized sugar) from water extract neutralized by Ca(OH)(2), NaOH, and Na(2)SO(3) were 0.16, 0.1 and 0.07, respectively, suggesting that Ca(OH)(2) had the best detoxification effect. PMID:21424838

  5. Laboratory Synthesized Calcium Oxide and Calcium Hydroxide Grains: A Candidate to Explain the 6.8 Micron Band

    NASA Technical Reports Server (NTRS)

    Kimura, Yuki; Nuth, Joseph A., III

    2005-01-01

    We will demonstrate that CaO and Ca(OH)2 are excellent candidates to explain the 6.8 microns feature, which is one of the most obscure features in young stellar objects. We discuss the condensation of CaO grains and the potential formation of a Ca(OH)2 surface layer. The infrared spectra of these grains are compared with the spectra of fifteen young stellar objects. We note that CaO-rich grains are seen in all meteoritic CAIs (calcium-aluminum-rich inclusions) and the 6.8 micron feature has only been observed in young stellar objects. Therefore, we consider CaO grains to be a plausible candidate to explain the 6.8 microns feature and hypothesize that they are produced in the hot interiors of young stellar environments.

  6. Influence of calcium compounds on the mechanical properties of fly ash geopolymer pastes.

    PubMed

    Temuujin, J; van Riessen, A; Williams, R

    2009-08-15

    The influence of calcium compounds (CaO and Ca(OH)(2)) on the mechanical properties of fly ash based geopolymers has been studied. Calcium compounds were substituted in fly ash at 1, 2 and 3 wt%, respectively. Curing of the geopolymers was performed at ambient temperature (20 degrees C) and 70 degrees C. Addition of calcium compounds as a fly ash substitute improved mechanical properties for the ambient temperature cured samples while decreasing properties for the 70 degrees C cured samples. Seven days compressive strength of the ambient temperature cured samples increased from 11.8 (2.9) to 22.8 (3.8)MPa and 29.2 (1.1)MPa for 3% CaO and 3% Ca(OH)(2) additions, respectively. PMID:19201089

  7. The 6.8 ? m band is caused by CaO grains

    NASA Astrophysics Data System (ADS)

    Kimura, Y.; Nuth, J. A., III

    2005-05-01

    Protostellar objects have several significant infrared. In this study, we will concentrate on the band observed at 6.8 ? m, one of the most obscure features in young stellar objects (YSOs) and one that is only observed in young stellar objects. Although several materials have been proposed to explain this feature, each of these candidates requires specific environmental conditions to explain the observations. We believe that a complex of CaO and Ca(OH)2 could explain observations of a 6.8 ? m feature in protostellar systems. We discuss the condensation of CaO grains and the formation of a Ca(OH)2 surface layer. The smoke samples were observed using a transmission electron microscope at the University of New Mexico. The infrared spectra of our samples had characteristic dual peaks centered at 6.8 um which was produced by absorption in CaO combined with absorption by a Ca(OH)2 layer on the surface of the CaO grains, produced by reaction with moisture upon exposure to air. The infrared spectra are compared with the spectra of fifteen YSOs. We note that CaO-rich grains are seen in all meteoritic CAIs (calcium-aluminum-rich inclusions), characteristic components of carbonaceous chondrites that must have been produced in the solar nebula. In addition, since CaO has a number of nebular formation routes, CaO could be present in young stellar environments to a significantly higher degree than would be implied by its abundance in meteorites. Moreover, the 6.8 ? m feature has only been observed in YSOs. Therefore, we believe that CaO grains (together with Ca(OH)2 coatings of varying thickness) are a plausible candidate to explain the 6.8 ? m features seen in YSOs and hypothesize that they are produced in the hot interiors of young stellar environments.

  8. Chemical Reduction of PCE by Zero Valent Iron Colloids Batch and Column Experiments

    E-print Network

    Cirpka, Olaf Arie

    [-] PCE - Inflow PCE - Outflow TCE - Inflow TCE - Outflow Chloride - Outflow Blank Value Chloride pH Value 34 39 43 48 Pore-Volume [-] pH[-] PCE - Outflow TCE - Outflow Chloride - Outflow Blank Value Chloride pH Value nZVI-reinjection NAPASAN Particle - nZVI & Ca(OH)2 / PCE-DNAPL 0 20 40 60 80 100 120 140 0

  9. Highly Ordered TiO2 Nanotubes Filled by Hydroxyapatite Nanoparticles for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Ulasevich, S. A.; Poznyak, S. K.; Skorb, E. V.; Kulak, A. I.

    2013-05-01

    Hydroxyapatite-containing coatings were prepared on a titanium substrate by chemical treatment of the anodic films with TiO2 nanotube arrays in Ca(OH)2 and (NH4)2HPO4 solutions using successive ion layer adsorption and reaction. The composite coatings obtained offer a good adhesion to the titanium implant and a high biocompatibility due to embedding hydroxyapatite nanoparticles into the vertical TiO2 nanopores.

  10. Intra-canal calcium hydroxide removal by two rotary systems: A comparative study

    PubMed Central

    Dadresanfar, Bahare; Abbas, Fateme Mashhadi; Bashbaghi, Hamide; Miri, Shima Sadat; Ghorbani, Farshid

    2015-01-01

    Aim: The presence of calcium hydroxide (Ca(OH)2) in the root canal interferes with the apical root canal sealing and may result in periapical lesions in the long run. The present study was aimed to compare the efficacy of two rotary systems of Race and Mtwo in the removal of Ca (OH)2 aqueous-based from distobuccal canals of human maxillary molars. Materials and Methods: A total of 44 distobuccal root canals of human maxillary molars were randomly distributed into two groups of 20 canals each and two control groups. Specimens in each group were instrumented with similar master apical rotary (MAR) and flexible files according to the manufacture's guidelines. The Ca (OH)2 paste was placed in canals using # 20 lentulo and radiographs were taken from the two dimensions. The roots were incubated for 1 week at 37°C and 100% humidity and Ca (OH)2 was removed from canals by MAR, afterward. Then, the roots were longitudinally split in halves by diamond disk and chisel without entering the root canals. Photos were taken from the canals’ walls by a stereomicroscope with × 10 magnification. Next, according to a defined scoring system, photos were scored by four endodontists, so that scores 1 and 2 (nonvisible remnants or scattered remnants of Ca(OH)2) were considered as acceptable and scores 3 and 4 (distinct mass or densely-packed mass of Ca(OH)2) were regarded as nonacceptable. Results: The obtained findings indicated that in coronal, middle, and apical portions of the root canal, 45, 60, and 65% of Mtwo specimens and 40, 50, and 55% of specimens prepared by the Race system acquired an acceptable score (1 and 2), respectively. Moreover, the results showed no significant difference between the two groups (P > 0.05). Conclusions: Both Mtwo and Race rotary systems with acceptable removal efficiency (score 1 and 2) were similarly able to remove Ca(OH)2 PMID:26069416

  11. Effects of Phosphoric Acid Concentration on Platinum Catalyst and Phosphoric Acid Hydrogen Pump Performance

    NASA Astrophysics Data System (ADS)

    Buelte, Steve

    This work involves the study of the operational performance of phosphoric acid based electrochemical hydrogen pumps with a polybenzimidazole (PBI) electrolytic membrane. During characterization of these devices, the power consumption was found to be highly sensitive to the water vapor pressure in the supply gas stream which in turn affects the phosphoric acid concentration. The power requirement was 30 times higher when the supply gas stream was not humidified than when the supply gas stream was humidified. Upon testing of electrochemical hydrogen pumps over a range of supply gas water vapor pressures from 150 to 0.8 mmHg, it was found that the effective platinum catalyst area decreases as phosphoric acid concentration increases in response to declining supply gas vapor pressure. It was hypothesized that the decline in the effective platinum catalyst area was caused by the adsorption of a species from the electrolyte that increases in concentration with phosphoric acid concentration. Polyphosphoric acid species were such a species which increased in concentration as phosphoric acid concentration increased and as a result were hypothesized to be the species adsorbing on the platinum catalyst. Additional testing was conducted in an electrochemical half cell in which the effect of phosphoric acid concentration on the platinum surface area at a single electrode interface could be studied. Impedance spectroscopy and cyclic voltammetry (CV) testing was used to measure changes in exchange current and platinum surface area following the exposure of the electrode to electrolyte. Platinum surface coverage estimates from CV measurements were 60-87% at a phosphoric acid concentration of 76 wt% P2O5 (105 wt% H3PO 4) and near 100% coverage at 83.3 wt% P2O5 (115 wt% H3PO4). The exchange current for hydrogen oxidation and reduction on platinum decreased by a factor of 25 for 76 wt% P2O 5 and a factor of 1000 for 83.3 wt% P2O5 phosphoric acid concentration within 36 hours. A similar dependence of platinum surface coverage and exchange current on phosphoric acid concentration was observed during hydrogen pump testing over a range of supply gas vapor pressures. This work indicates that platinum catalyst activity declines sharply above a phosphoric acid concentration of 72.4 wt% P2O5 (100 wt% H3PO4) which causes a significant increase in hydrogen pump power consumption. To reduce power consumption, the hydrogen gas supplied to the hydrogen pump requires humidification to a vapor pressure of at least 55 mmHg. The addition of humidification to the supply gas stream adds complexity to a system incorporating a phosphoric acid hydrogen pump. The need to add humidification equipment to reduce phosphoric acid hydrogen pump power consumption may have a significant impact when such devices are applied to hydrogen separation applications including hydrogen recovery from industrial exhaust streams and for emerging alternative energy applications.

  12. Transport and spectroscopic studies of liquid and polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Bopege, Dharshani Nimali

    Liquid and polymer electrolytes are interesting and important materials to study as they are used in Li rechargeable batteries and other electrochemical devices. It is essential to investigate the fundamental properties of electrolytes such as ionic conductivity, diffusion, and ionic association to enhance battery performance in different battery markets. This dissertation mainly focuses on the temperature-dependent charge and mass transport processes and ionic association of different electrolyte systems. Impedance spectroscopy and pulsed field gradient nuclear magnetic resonance spectroscopy were used to measure the ionic conductivity and diffusion coefficients of ketone and acetate based liquid electrolytes. In this study, charge and mass transport in non-aqueous liquid electrolytes have been viewed from an entirely different perspective by introducing the compensated Arrhenius formalism. Here, the conductivity and diffusion coefficient are written as an Arrhenius-like expression with a temperature-dependent static dielectric constant dependence in the exponential prefactor. The compensated Arrhenius formalism reported in this dissertation very accurately describes temperature-dependent conductivity data for acetate and ketone-based electrolytes as well as temperature-dependent diffusion data of pure solvents. We found that calculated average activation energies of ketone-based electrolytes are close to each other for both conductivity and diffusion data (in the range 24-26 kJ/mol). Also, this study shows that average activation energies of acetate-based electrolytes are higher than those for the ketone systems (in the range 33-37 kJ/mol). Further, we observed higher dielectric constants and ionic conductivities for both dilute and concentrated ketone solutions with temperature. Vibrational spectroscopy (Infrared and Raman) was used to probe intermolecular interactions in both polymer and liquid electrolytes, particularly those which contain lithium trifluoromethanesulfonate, LiCF3SO3, abbreviated here as lithium triflate(LiTf). The molar absorption coefficients of nus(SO3), deltas(CF3), and deltas(SO3) vibrational modes of triflate anion in the LiTf-2-pentanone system were found to be 6708+/-89, 5182+/-62, and 189+/-2 kg mol-1 cm-1, respectively using Beer-Lambert law. Our results show that there is strong absorption by nu s(SO3) mode and weak absorption by deltas(CF 3) mode. Also, the absorptivity of each mode is independent of the ionic association with Li ions. This work allows for the direct quantitative comparison of calculated concentrations in different samples and different experimental conditions. In addition, this dissertation reports the temperature-dependent vibrational spectroscopic studies of pure poly(ethylene oxide) and LiTf-poly(ethylene oxide) complexes. A significant portion of this dissertation focuses on crystallographic studies of ketone-salt (LiTf:2-pentanone and NaTf:2-hexanone) and amine-acid (diethyleneamine: H3PO4, N,N'-dimethylethylenediamine:H 3PO4, and piperazine:H3PO4) systems. Here, sodium trifluoromethanesulfonate, NaCF3SO3 is abbreviated as NaTf. As model compounds, these systems provide valuable information about ion-ion interactions, which are helpful for understanding complex polymer systems. During this study, five crystal structures were solved using single X-ray diffractometry, and their vibrational modes were studied in the mid-infrared region. In the secondary amine/phosphoric acid systems, the nature of hydrogen-bonding network was examined.

  13. Combined thermo-chemo-sonic disintegration of waste activated sludge for biogas production.

    PubMed

    Kavitha, S; Yukesh Kannah, R; Yeom, Ick Tae; Do, Khac-Uan; Banu, J Rajesh

    2015-12-01

    In the present study, there was an investigation about the impact of a new combined thermo-chemo-sonic disintegration of waste activated sludge (WAS) on biodegradability. The outcome of sludge disintegration reveals that maximum Suspended Solids (SS) reduction and Chemical Oxygen Demand (COD) solubilization effectuated at a specific energy input of 5290.5kJ/kgTS, and was found to be 20%, 16.4%, 15% and 27%, 22%, and 20%, respectively for the three alkalis (NaOH, KOH, and Ca(OH)2). The conversion coefficient of the Volatile Suspended Solids (VSS) to product Soluble COD (SCOD), calculated by nonlinear regression modeling, was found to be 0.5530gSCOD/gVSS, 0.4587gSCOD/gVSS, and 0.4195gSCOD/gVSS for NaOH, KOH, and Ca(OH)2, respectively. In the biodegradability studies, the parameter evaluation provides an estimate of parameter uncertainty and correlation, and elucidates that there is no significant difference in biodegradability (0.413gCOD/gCOD, 0.367gCOD/gCOD, and 0.342gCOD/gCOD) for three alkalis (NaOH, KOH, and Ca(OH)2). PMID:26356110

  14. The generation of HCl in the system CaCl2-H2O: Vapor-liquid relations from 380-500°C

    USGS Publications Warehouse

    Bischoff, James L.; Rosenbauer, Robert J.; Fournier, Robert O.

    1996-01-01

    We determined vapor-liquid relations (P-T-x) and derived critical parameters for the system CaCl2-H2O from 380-500??C. Results show that the two-phase region of this system is extremely large and occupies a significant portion of the P-T space to which circulation of fluids in the Earth's crust is constrained. Results also show the system generates significant amounts of HCl (as much as 0.1 mol/kg) in the vapor phase buffered by the liquid at surprisingly high pressures (???230 bars at 380??C, <580 bars at 500??C), presumably by hydrolysis of CaCl2: CaCl2 + 2H2O = Ca(OH)2 + 2HCl. We interpret the abundance of HCl in the vapor as due to its preference for the vapor phase, and by the preference of Ca(OH)2 for either the liquid phase or solid. The recent recognition of the abundance of CaCl2 in deep brines of the Earth's crust and their hydrothermal mobilization makes the hydrolysis of CaCl2 geologically important. The boiling of Ca-rich brines produces abundant HCl buffered by the presence of the liquid at moderate pressures. The resultant Ca(OH)2 generated by this process reacts with silicates to form a variety of alteration products, such as epidote, whereas the vapor produces acid-alteration of rocks through which it ascends.

  15. Comparison of seven chemical pretreatments of corn straw for improving methane yield by anaerobic digestion.

    PubMed

    Song, Zilin; GaiheYang; Liu, Xiaofeng; Yan, Zhiying; Yuan, Yuexiang; Liao, Yinzhang

    2014-01-01

    Agriculture straw is considered a renewable resource that has the potential to contribute greatly to bioenergy supplies. Chemical pretreatment prior to anaerobic digestion can increase the anaerobic digestibility of agriculture straw. The present study investigated the effects of seven chemical pretreatments on the composition and methane yield of corn straw to assess their effectiveness of digestibility. Four acid reagents (H2SO4, HCl, H2O2, and CH3COOH) at concentrations of 1%, 2%, 3%, and 4% (w/w) and three alkaline reagents (NaOH, Ca(OH)2, and NH3·H2O) at concentrations of 4%, 6%, 8%, and 10% (w/w) were used for the pretreatments. All pretreatments were effective in the biodegradation of the lignocellulosic straw structure. The straw, pretreated with 3% H2O2 and 8% Ca(OH)2, acquired the highest methane yield of 216.7 and 206.6 mL CH4 g VS(-1) in the acid and alkaline pretreatments, which are 115.4% and 105.3% greater than the untreated straw. H2O2 and Ca(OH)2 can be considered as the most favorable pretreatment methods for improving the methane yield of straw because of their effectiveness and low cost. PMID:24695485

  16. Hydrothermal treatment of naturally contaminated maize in the presence of sodium metabisulfite, methylamine and calcium hydroxide; effects on the concentration of zearalenone and deoxynivalenol.

    PubMed

    Rempe, Inga; Kersten, Susanne; Valenta, Hana; Dänicke, Sven

    2013-08-01

    Fusarium toxin-contaminated ground maize was hydrothermally treated in the presence of different combinations of chemicals in order to simultaneously reduce zearalenone (ZEA) and deoxynivalenol (DON) concentrations. Treatments were carried out in a laboratory conditioner at 80 °C and 17 % moisture. Six different treatments were performed, consisting of 3 doses of methylamine (MMA; 2.5, 5 and 10 g/kg maize) at a constant dose of 5 g sodium metabisulfite (SBS)/kg, either with or without the addition of 20 g calcium hydroxide (Ca(OH)2)/kg. The used maize was contaminated with approximately 45.99 mg DON/kg and 3.46 mg ZEA/kg. Without the addition of Ca(OH)2, DON reductions reached approximately 82% after 1-min treatment and the toxin disappeared nearly completely after 10 min when 2.5 or 5 g MMA were applied. ZEA concentrations were only marginally affected. In the presence of Ca(OH)2, reductions in DON concentrations were lower, but were enhanced by increasing doses of MMA. ZEA concentrations were reduced by 72, 85 and 95% within the first 5 min of the treatment at MMA dosages of 2.5, 5 and 10 g/kg maize, respectively. The application of SBS in combination with a strong alkaline during hydrothermal treatment seems to be a promising approach to simultaneously decontaminate even high amounts of DON and ZEA in ground maize and may contribute to reduce the toxin load of diets. PMID:23536360

  17. The effect of antibiotics and endodontic antimicrobials on the polymerase chain reaction.

    PubMed

    Fouad, Ashraf F; Barry, Jody

    2005-07-01

    The effectiveness of endodontic antimicrobial treatment could be determined using sensitive molecular methods. The purpose of this study was to determine if antibiotics or endodontic reagents interfere with the ability of PCR to detect Enterococcus faecalis in vitro. Amoxicillin (25 mg/ml), clindamycin (15 mg/ml), tetracycline (25 mg/ml), doxycycline (10 mg/ml), calcium hydroxide, 1% buffered sodium hypochlorite (NaOCl1), 3% and 6% unbuffered NaOCl (NaOCl3 and NaOCl6), 2% chlorhexidine (CHX), 5% tincture iodine (TI), 2% iodine potassium iodide (IKI), chloroform (CF), 70% ethyl alcohol, 5% sodium thiosulphate, 5% citric acid or saline were added to 10 or 10 cells/ml E. faecalis ATCC 19433 for 1 h (1 wk for Ca(OH)2). Using PCR, all specimens were positive except for NaOCl3 and NaOCl6. PCR with Ca(OH)2 was positive with 10 cells/ml but negative with 10 cells/ml. The following reagents yielded negative culturing results: all antibiotics, Ca(OH)2, CHX, IKI, TI, NaOCl3, NaOCl6, and CF. BacLight nuclear staining revealed the presence of viable cells in all PCR positive, culture negative combinations, except for those with CF. Therefore, in the presence of threshold values of bacterial concentrations, all reagents tested except for NaOCl3 and NaOCl6 do not interfere with the detection of E. faecalis using PCR. PMID:15980710

  18. Comparison of Seven Chemical Pretreatments of Corn Straw for Improving Methane Yield by Anaerobic Digestion

    PubMed Central

    Song, Zilin; GaiheYang; Liu, Xiaofeng; Yan, Zhiying; Yuan, Yuexiang; Liao, Yinzhang

    2014-01-01

    Agriculture straw is considered a renewable resource that has the potential to contribute greatly to bioenergy supplies. Chemical pretreatment prior to anaerobic digestion can increase the anaerobic digestibility of agriculture straw. The present study investigated the effects of seven chemical pretreatments on the composition and methane yield of corn straw to assess their effectiveness of digestibility. Four acid reagents (H2SO4, HCl, H2O2, and CH3COOH) at concentrations of 1%, 2%, 3%, and 4% (w/w) and three alkaline reagents (NaOH, Ca(OH)2, and NH3·H2O) at concentrations of 4%, 6%, 8%, and 10% (w/w) were used for the pretreatments. All pretreatments were effective in the biodegradation of the lignocellulosic straw structure. The straw, pretreated with 3% H2O2 and 8% Ca(OH)2, acquired the highest methane yield of 216.7 and 206.6 mL CH4 g VS ?1 in the acid and alkaline pretreatments, which are 115.4% and 105.3% greater than the untreated straw. H2O2 and Ca(OH)2 can be considered as the most favorable pretreatment methods for improving the methane yield of straw because of their effectiveness and low cost. PMID:24695485

  19. Phase relations in the system NaCl-KCl-H 2O II: Differential thermal analysis of the halite liquidus in the NaCl-H 2O binary above 450°c

    NASA Astrophysics Data System (ADS)

    Gunter, W. D.; Chou, I.-Ming; Girsperger, Sven

    1983-05-01

    Thermal analysis of the halite liquidus in the system NaCl-H 2O has been conducted for NaCl mole fractions ( XNaCl) greater than 0.25 ( i.e., > 50 wt. % NaCl) at pressures between 0.3 and 4.1 kb and temperatures greater than 450°C. The position of the liquidus was located by differential thermal analysis (DTA) of cooling scans only, as heating scans did not produce definitive DTA peaks. The dP/dT slope of the liquidus is positive and steep at high pressures, but at high XNaCl, and pressures below 0.5 kb it appears to reverse slope and intersects the three-phase curve (liquid-halite-vapour) at a shallow angle. However, due to the complex nature of the DTA signal when P <- 0.5 kb, there is considerable doubt about exactly what event has been recorded in the experiments conducted at these low pressures. The solubility of halite can be expressed as a function of the mole-fractional-based activity of NaCl in the liquid phase ( L) in temperature (T, °K) and pressure (P, bars) In ? NaCl(L.T.P) = -19.884 - 0.001275T - 1388/T + 3.2305 In (T) - 0.07574PT Our liquidus data (based on 10 compositions) above 500 bars for these brines were combined with this equation to generate activity coefficients of NaCl which were fit within their experimental uncertainties to the following one parameter Margules equation In ? NaCl(L.T.P) = (0.7268 - 695.7/T - 0.1217PT)(1 - X NaCl) 2. Concentrated solutions of NaCl show negative deviations from ideality which rapidly increase in magnitude with decreasing XNaCl.

  20. The generation of HCl in the system NaCl-KCl-H{sub 2}O-quartz at 600{degrees}C: Implications regarding HCl in natural systems at lower temperatures

    SciTech Connect

    Fournier, Robert O.; Thompson, J. Michael

    1993-01-28

    In experiments at 600°C in the system NaCI-KCI-H2O, within the analytical uncertainty, stoichiometric quantities of Cl and total alkali metals (Na+K) appear to dissolve in steam coexisting with chloride-rich brine at high pressures in the absence of solid salt. In contrast, at lower pressures, where steam coexists with precipitated salts, significant excess chloride as associated hydrogen chloride (HCI°) dissolves in steam. The HCI° appears to be generated by the reaction of solid NaCl(s) (halite) with steam, producing solid NaOH(s) that diffuses into halite, forming a solid solution. Where HCI° is present highly associated NaOH° as well as associated NaCI° appear to dissolve in steam, and the solubility of each is increased as the mole fraction of NaOH(s) in halite increases. In our quasi-static experiments, compared to dynamic flow-through experiments of others, higher initial ratios of H2O/NaCI have resulted in higher mole fractions of NaOH(s) in solid solution in halite and, accordingly, higher solubilities of NaCI" and NaOH" dissolved in steam. Addition of quartz to the system NaCI-KCI-H2O results in the formation of sodium disilicate by reaction of silica with NaOH(s) and an order of magnitude increase in the concentration of HCl° dissolved in steam. In natural hydrothermal systems at lower temperatures where brine or brine plus steam are present in the absence of precipitated salt, the pH of the brine is controlled mainly by base exchange reactions involving a variety of silicates that fix Na+/H+ and K+/H+ activity ratios. Where feldspars are present pH values generally are near neutral. Where mica, but no feldspar is present pH values may become only moderately acid. High acidity in salt-absent brine systems occurs only where all feldspars and mica have been altered to other minerals (generally pyrophyllite/ kaolinite or alunite). The situation changes significantly when salt precipitates. Hydrolysis produces HCI° by the reaction of water with NaCl when halite is present. The NaOH(s) that is produced as a byproduct is likely to react with quartz plus various alumino-silicates, producing a variety of alteration products and allowing steam to become greatly enriched in HCl° compared to the composition of steam that is attained in the simple system NaCI-KCI-H2O with halite present. Also, when a natural high-temperature hydrothermal system changes from one in which the pore fluid is brine to one in which the pore fluid is dry steam there is a drastic change in Na+/H+ and K+/H+ activity ratios in the pore fluid because the hydrogen ions that were predominantly dissociated species in the brine become predominantly associated species in steam. The net result is the stabilization of alkali feldspars in contact with steam that may contain appreciable HCI° that is produced by the reaction of precipitated salt with the steam.

  1. Phase relations in the system NaCl-KCl-H2O II: Differential thermal analysis of the halite liquidus in the NaCl-H2O binary above 450°c

    USGS Publications Warehouse

    Gunter, W.D.; Chou, I.-Ming; Girsperger, Sven

    1983-01-01

    The solubility of halite can be expressed as a function of the mole-fractional-based activity of NaCl in the liquid phase (L) in temperature (T, °K) and pressure (P, bars) In  Our liquidus data (based on 10 compositions) above 500 bars for these brines were combined with this equation to generate activity coefficients of NaCl which were fit within their experimental uncertainties to the following one parameter Margules equation In . Concentrated solutions of NaCl show negative deviations from ideality which rapidly increase in magnitude with decreasing XNaCl.

  2. The electrochemical measurements were conducted using a three-electrode cell at 25 C. A Pt wire and an Ag/AgCl (in saturated KCl) were used as the

    E-print Network

    Gao, Hongjun

    using hollow graphitic nanoparticles or commercial cata- lyst) and cathode (Pt black, Johnson by pressing the as-prepared cathode and anode layers onto both sides of a pre-treated Nafion 117 electrolyte

  3. Measurement of delta13C and delta18O Isotopic Ratios of CaCO3 by a Thermoquest Finnigan GasBench II Delta Plus XL Continous Flow Isotope Ratio Mass Spectrometer with Application to Devils Hole Core DH-11 Calcite

    USGS Publications Warehouse

    Revesz, Kinga M.; Landwehr, Jurate Maciunas; Keybl, Jaroslav Edward

    2001-01-01

    A new method was developed to analyze the stable carbon and oxygen isotope ratios of small samples (400?20 ?g) of calcium carbonate. This new method streamlines the classical phosphoric acid - calcium carbonate (H3PO4 - CaCO3) reaction method by making use of a Thermoquest-Finnigan GasBench II preparation device and a Delta Plus XL continuous flow isotope ratio mass spectrometer. To obtain reproducible and accurate results, optimal conditions for the H3PO4 - CaCO3 reaction had to be determined. At the acid-carbonate reaction temperature suggested by the equipment manufacturer, the oxygen isotope ratio results were unsatisfactory (standard deviation () greater than 1.5 per mill), probably because of a secondary reaction. When the acid-carbonate reaction temperature was lowered to 26?C and the reaction time was increased to 24 hours, the precision of the carbon and oxygen isotope ratios for duplicate analyses improved to 0.1 and 0.2 per mill, respectively. The method was tested by analyzing calcite from Devils Hole, Nevada, which was formed by precipitation from ground water onto the walls of a sub-aqueous cavern during the last 500,000 years. Isotope-ratio values previously had been obtained by the classical method for Devils Hole core DH-11. The DH-11 core had been recently re-sampled, and isotope-ratio values were obtained using this new method. The results were comparable to those obtained by the classical method. The consistency of the isotopic results is such that an alignment offset could be identified in the re-sampled core material, a cutting error that was then independently confirmed. The reproducibility of the isotopic values is demonstrated by a correlation of approximately 0.96 for both isotopes, after correcting for an alignment offset. This result indicates that the new method is a viable alternative to the classical method. In particular, the new method requires less sample material permitting finer resolution and allows automation of some processes resulting in considerable timesavings.

  4. Immobilization of EAFD heavy metals using acidic materials.

    PubMed

    Mitrakas, Manassis G; Sikalidis, Constantinos A; Karamanli, Theoktisti P

    2007-03-01

    This study was undertaken to determine the chemical and leaching characteristics of the Electric Arc Furnace Dust (EAFD) generated by a Greek plant and to investigate various acidic materials efficiency on the EAFD stabilization. In order to investigate how [OH(-)] neutralization influences EAFD heavy metals leachability, Na HCO3(-), HNO3 and H3PO4 were used as acidic materials. The concentration of Pb in leachate was found between 40 and 3.7 x 10(3) mg Pb/kg of EAFD, exceeding in all EAFD samples the maximum acceptable limit (MAL) 25 mg/kg for landfill disposal. Neutralization of [OH(-)] with HCO3(-) decreased Pb concentration in leachate at 350 mg Pb/kg of EAFD, while excess over a stoichiometry in HCO3(-) addition increased leachability of Pb, Cd, Cr, Cu as well as F. Using HNO3 as an acidic material decreased leachability of almost all the parameters concerning the EC directive 33/19-01-2003 in a pH value up to 7.2, in exception of Zn. Zinc leachability showed a U shape curve as a function of pH value. The concentration of Zn was minimized in a concentration lower than 1 mg Zn/kg EAFD in a pH range 10.5 to 9 and exceeded the MAL 90 mg/kg at a pH value 7.2. However, the major disadvantage of HNO3 was proved to be its leachability, since NO3(-) concentration in leachate was equal to HNO3 dose. H3PO4 was found the most promising acidic material for the chemical immobilization of heavy metals, since it decreased their leachability in a concentration significantly lower than MAL at a pH value up to 7.1. Finally, the concentration of Cl(-) ranged between 18 and 33 x 10(3) mg Cl(-)/kg EAFD exceeding in all EAFD samples the MAL 17 x 10(3) mg/kg. This high concentration of Cl(-) is attributed to the scrap and it could be reduced only by modification of its composition. PMID:17365324

  5. High precision Nd isotope measurements of nanogram to sub-nanogram size samples: initial results from magnetic microspherules from Younger Dryas Boundary

    NASA Astrophysics Data System (ADS)

    Wu, Y.; West, A.; Sharma, M.

    2010-12-01

    We are developing techniques to precisely measure Nd, Sr, and Os isotopes in single/aggregate magnetic microspherules recovered from Younger Dryas Boundary. For Nd isotopes this requires measurement of samples containing ~100 pg to ? 1 ng of Nd. Due to the high efficiency of the generation of NdO+ ions over Nd+ ions in the thermal ionization mass spectrometer high precision measurements of Nd isotopes with loads of 10-20 ng have typically involved measuring Nd as NdO+ [Wasserburg et al., 1981]. This technique has been further extended to measure Nd down about one ng [e.g., 2-3]. The NdO+ ions are generated by increasing the partial pressure of O2 in the ion source by either a) bleeding oxygen in to the ion source or b) by reducing the pumping of the ion source. Both of these techniques require specialized apparatus and the data obtained tend to be impacted by the uncertainty in the oxygen isotope composition [Prinzhofer et al., 1992]. To overcome these issues techniques that supply oxygen from an emitter that is loaded along with Nd directly on the filament have been developed. Two types of emitters have been used: 1) Silica gel-H3PO4 or 2) Ta2O5-H3PO4. Here we use the latter technique to obtain NdO+ ions. In our study, 10 loads of 1ng Nd of a standard solution Caltech nNd? standard yield 0.1-0.3 V beams on 144Nd16O+ with ?Nd = -14.50 ± 0.65 (2?, external reproducibility). This method permits the analysis of small (hundreds of micrograms) microspherule samples at the Younger Dryas Boundary where total amount of Nd are very low (a few nanograms). Our initial analyses of a cluster of microspherules from the Younger Dryas boundary Pennsylvania gives ?Nd = -11.50 ± 1.46 ([Nd] = 30 ppm). The corresponding 87Sr/86Sr and 187Os/188Os ratios of this cluster are 0.7124 ([Sr] =75 ppm) and 1.08 ([Os] = 1.339 ppb), respectively. The data indicate that the provenance of these spherules is ancient upper crust similar to that found on the eastern Seaboard.

  6. ?13C and ?18O isotopic composition of CaCO3 measured by continuous flow isotope ratio mass spectrometry: statistical evaluation and verification by application to Devils Hole core DH-11 calcite

    USGS Publications Warehouse

    Revesz, Kinga M.; Landwehr, Jurate M.

    2002-01-01

    A new method was developed to analyze the stable carbon and oxygen isotope ratios of small samples (400?±?20?µg) of calcium carbonate. This new method streamlines the classical phosphoric acid/calcium carbonate (H3PO4/CaCO3) reaction method by making use of a recently available Thermoquest-Finnigan GasBench II preparation device and a Delta Plus XL continuous flow isotope ratio mass spectrometer. Conditions for which the H3PO4/CaCO3 reaction produced reproducible and accurate results with minimal error had to be determined. When the acid/carbonate reaction temperature was kept at 26?°C and the reaction time was between 24 and 54?h, the precision of the carbon and oxygen isotope ratios for pooled samples from three reference standard materials was ?0.1 and ?0.2 per mill or ‰, respectively, although later analysis showed that materials from one specific standard required reaction time between 34 and 54?h for ?18O to achieve this level of precision. Aliquot screening methods were shown to further minimize the total error. The accuracy and precision of the new method were analyzed and confirmed by statistical analysis. The utility of the method was verified by analyzing calcite from Devils Hole, Nevada, for which isotope-ratio values had previously been obtained by the classical method. Devils Hole core DH-11 recently had been re-cut and re-sampled, and isotope-ratio values were obtained using the new method. The results were comparable with those obtained by the classical method with correlation?=?+0.96 for both isotope ratios. The consistency of the isotopic results is such that an alignment offset could be identified in the re-sampled core material, and two cutting errors that occurred during re-sampling then were confirmed independently. This result indicates that the new method is a viable alternative to the classical reaction method. In particular, the new method requires less sample material permitting finer resolution and allows automation of some processes resulting in considerable time savings. 

  7. New solvent systems for gradient counter-current chromatography in separation of betanin and its derivatives from processed Beta vulgaris L. juice.

    PubMed

    Spórna-Kucab, Aneta; Garrard, Ian; Ignatova, Svetlana; Wybraniec, S?awomir

    2015-02-01

    Betalains, natural plant pigments, are beneficial compounds due to their antioxidant and possible chemoprotective properties. A mixture of betalains: betanin/isobetanin, decarboxybetanins and neobetanin from processed red beet roots (Beta vulgaris L.) juice was separated in food-grade, gradient solvent systems using high-performance counter-current chromatography (HPCCC). The decarboxylated and dehydrogenated betanins were obtained by thermal degradation of betanin/isobetanin from processed B. vulgaris L. juice under mild conditions. Two solvent systems (differing in their composition by phosphoric acid and ethanol volume gradient) consisting of BuOH-EtOH-NaClsolution-H2O-H3PO4 (v/v/v/v/v, 1300:200-1000:1300:700:2.5-10) in the 'tail-to-head' mode were run. The flow rate of the mobile phase (organic phase) was 1.0 or 2.0 ml/min and the column rotation speed was 1,600 rpm (20°C). The retention of the solvent system stationary phase (aqueous phase) was ca. 80%. The system with the acid and ethanol volume gradient consisting of BuOH-EtOH-NaClsolution-H2O-H3PO4 (v/v/v/v/v, 1300:200-240:1300:700:2.5-4.5) pumped at 2.0 ml/min was the most effective for a separation of betanin/isobetanin, 17-decarboxy-betanin/-isobetanin, 2-decarboxy-betanin/-isobetanin, 2,17-bidecarboxy-betanin/-isobetanin pairs as well as neobetanin. The pigments were detected by LC-DAD and LC-MS. The results are crucial in the application of completely food-grade solvent systems in separation of food-grade compounds as well, and the systems can possibly be extended to other ionizable and polar compounds with potential health benefits. In particular, the method is applicable for the isolation and purification of betalains present in such rich sources as B. vulgaris L. roots as well as cacti fruits and Amaranthaceae flowering plants due to modification possibilities of the solvent systems polarity. PMID:25595533

  8. Biaxially stretchable supercapacitors based on the buckled hybrid fiber electrode array

    NASA Astrophysics Data System (ADS)

    Zhang, Nan; Zhou, Weiya; Zhang, Qiang; Luan, Pingshan; Cai, Le; Yang, Feng; Zhang, Xiao; Fan, Qingxia; Zhou, Wenbin; Xiao, Zhuojian; Gu, Xiaogang; Chen, Huiliang; Li, Kewei; Xiao, Shiqi; Wang, Yanchun; Liu, Huaping; Xie, Sishen

    2015-07-01

    In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times.In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times. Electronic supplementary information (ESI) available: SEM images of the twist-first hybrid fiber, TEM images of SWCNT/PEDOT hybrid bundles, Raman spectra and FTIR spectra of the hybrid electrodes, CVs of the pristine, bended and wound supercapacitor, transmittance spectra of the pristine and stretched supercapacitor, demo video of the supercapacitor. See DOI: 10.1039/c5nr03027g

  9. Context-dependent effects on the hydrophilicity/hydrophobicity of side-chains during reversed-phase high-performance liquid chromatography: Implications for prediction of peptide retention behaviour

    PubMed Central

    Mant, C.T.; Hodges, R.S.

    2009-01-01

    The present study set out to investigate whether observed relative hydrophilicity/hydrophobicity values of positively charged side-chains (with Lys and Arg as representative side-chains) or hydrophobic side-chains (with Ile as the representative side-chain) were context-dependent, i.e., did such measured values vary depending on characteristics of the peptides within which such side-chains are substituted (overall peptide hydrophobicity, number of positive charges) and/or properties of the mobile phase (anionic counterions of varying hydrophobicity and concentration)? Reversed-phase high-performance liquid chromatography (RP-HPLC) was applied to two series of four synthetic peptide analogues (+1, +2, +3 and +4 net charge), the only difference between the two peptide series being the substitution of one hydrophobic Ile residue for a Gly residue, in the presence of anionic ion-pairing reagents of varying hydrophobicity (HCOOH ? H3PO4 < TFA < PFPA < HFBA) and concentration (2–50 mM). RP-HPLC of these peptide series revealed that the relative hydrophilicity of Lys and Arg side-chains in the peptides increased with peptide hydrophobicity. In addition the relative hydrophobicity of Ile decreased dramatically with an increase in the number of positive charges in the peptide, this hydrophobicity decrease being of greater magnitude as the hydrophobicity of the anionic ion-pairing reagent increased. These results have significant implications in the prediction of peptide retention times for proteomic applications. PMID:16814308

  10. The perchlorate anion is more effective than the trifluoroacetate anion as an ion-pairing reagent for reversed-phase chromatography of peptides

    PubMed Central

    Shibue, M.; Mant, C.T.; Hodges, R.S.

    2009-01-01

    The addition of salts, specifically sodium perchlorate (NaClO4), to mobile phases at acidic pH as ion-pairing reagents for reversed-phase high-performance liquid chromatography (RP-HPLC) has been generally overlooked. To demonstrate the potential of NaClO4 as an effective anionic ion-pairing reagent, we applied RP-HPLC in the presence of 0–100 mM sodium chloride (NaCl), sodium trifluoroacetate (NaTFA) or NaClO4 to two mixtures of synthetic 18-residue peptides: a mixture of peptides with the same net positive charge (+4) and a mixture of four peptides of +1, +2, +3 and +4 net charge. Interestingly, the effect of increasing NaClO4 concentration on increasing peptide retention times and selectivity changes was more dramatic than that of either NaCl or NaTFA, with the order of increasing anion effectiveness being Cl? ?TFA? < ClO4?. Such effects were more marked when salt addition was applied to eluents containing 10 mM phosphoric acid (H3PO4) compared to 10 mM trifluoroacetic acid (TFA) due to the lesser starting anion hydrophobicity of the former mobile phase (containing the phosphate ion) compared to the latter (containing the TFA? ion). PMID:16013614

  11. Detection of two minor phosphorylation sites for bovine ?-casein macropeptide by reversed-phase liquid chromatography-tandem mass spectrometry.

    PubMed

    Hernández-Hernández, Oswaldo; Lebrón-Aguilar, Rosa; Quintanilla-López, Jesús E; Sanz, M Luz; Moreno, F Javier

    2011-10-26

    This work addresses the characterization of phosphopeptides in bovine ?-casein macropeptide by reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry (RPLC-ESI-MS(2)). Two different mass spectrometers, equipped with an ion trap (IT) or a quadrupole time-of-flight (Q-TOF) analyzer, were used to perform an accurate phosphorylation site assignment. A total of 8 phosphopeptides from 26 identified peptides were characterized. MS(2) spectra of phosphopeptides were dominated by the neutral loss of a phosphoric acid molecule (H(3)PO(4)) and sufficient informative fragment ions resulting from peptide backbone cleavages enabling the elucidation of the phosphopeptide sequence. A higher number of sequence informative b and y ions were detected using a Q-TOF instead of an IT analyzer. In addition to the well-established phosphorylation sites at Ser(149) and Ser(127), this study also revealed the presence of two minor phosphorylation sites at Thr(145) and Ser(166). These findings indicate that RPLC-ESI-MS(2) on a Q-TOF analyzer is a useful technique for identifying low-abundance phosphorylation sites in caseins. PMID:21910405

  12. Cellobiose dehydrogenase formation by filamentous fungus Chaetomium sp. INBI 2-26(-).

    PubMed

    Vasil'chenko, L G; Khromonygina, V V; Karapetyan, K N; Vasilenko, O V; Rabinovich, M L

    2005-09-22

    Laccase-negative filamentous fungus INBI 2-26(-) isolated from non-sporulating laccase-forming fungal association INBI 2-26 by means of protoplast technique was identified as Chaetomium sp. based on partial sequence of its rRNA genes. In the presence of natural cellulose sources, the strain secreted neutral cellobiose dehydrogenase (CDH) activity both in pure culture and in co-culture with laccase-positive filamentous fungus INBI 2-26(+) isolated from the same association. INBI 2-26(-) also secreted CDH during submerged cultivation in minimal medium with glucose as the sole carbon source. Maximal CDH activity of 1IU/ml at pH 6 with 2,6-dichlorophenolindophenol (DCPIP) as an acceptor was obtained on 12th day of submerged cultivation with filter paper as major cellulose source. Cellulase system of Chaetomium sp. INBI 2-26(-) capable of adsorption onto H(3)PO(4)-swollen filter paper consisted of four major proteins (Mr 200, 95, 65 and 55K) based on SDS-polyacrylamide gel electrophoresis and was capable of DCPIP reduction without exogenous cellobiose. PMID:15996782

  13. The structure and stability of the anodic electrochemical interface in a high temperature polymer electrolyte membrane fuel cell under reformate feed

    NASA Astrophysics Data System (ADS)

    Geormezi, Maria; Paloukis, Fotis; Orfanidi, Alin; Shroti, Nivedita; Daletou, Maria K.; Neophytides, Stylianos G.

    2015-07-01

    The effect of reformate H2 mixture composition on Pt/C based high temperature PEMFC anode was thoroughly studied, in order to understand the anode's tolerance under varying CO and steam partial pressures. It is shown that under steam partial pressure over 12 kPa a high overpotential region appears at current densities over 0.3 A/cm2. This negative effect appears in relation to the structure of the electrochemical interface (EI), as this is specified by the amount of H3PO4 (PA) within the anode catalytic layer. As also shown, the sustainable operation of the anode under reformate containing steam and CO as high as 30 kPa and 2 kPa respectively requires significantly lower loadings of PA. This malfunctioning is attributed to the hydrophobic/hydrophilic properties of the Pt/C-PA EI and its modification when water from the gas phase is dissolved in the PA, in combination with the polarization and the adsorption of CO and H2 on Pt surface. These phenomena and the capillary forces within the catalytic layer are responsible for the alternating contraction (ganglia formation and loss of ionic link within the EI) and spreading (thin film formation and well developed EI) of PA, thus giving rise to oscillatory behavior and unstable performance of the anode.

  14. Phosphoric acid as an electrolyte additive for lead/acid batteries in electric-vehicle applications

    NASA Astrophysics Data System (ADS)

    Meissner, E.

    The influence of the addition of phosphoric acid to the electrolyte on the performance of gelled lead/acid electric-vehiicle batteries is investigated. This additive reduces the reversible capacity decay of the positive electrode significantly which is observed upon extended cycling when recharge of the battery is performed at low initial rate. This is important when low-rate on-board chargers are used. Pulsed discharge, typical for electric-vehicle application, induces reversible capacity decay more than constant-current discharge at a same depth-of-discharge, as well with as without the addition of phosphoric acid. By contrast, hindrance in presence of H 3PO 4 for both the recharge and the discharge reaction helps to homogenize the state of many individual cells during cycling in long battery strings. Reversible capacity loss, which occurs after extended cycling and when pulsed discharge is applied, can be recovered by a single discharge at very low rate with batteries with and without the addition of phosphoric acid. The discharge-rate dependency of the capacity is significantly reduced when phosphoric acid is added. The pulse discharge behaviour may be better, even if the nominal capacity is reduced. The experimental findings of the influence of phosphoric acid addition is discussed in terms of the aggregate-of-spheres model of reversible capacity decay.

  15. Surface state of GaN after rapid-thermal-annealing using AlN cap-layer

    NASA Astrophysics Data System (ADS)

    El-Zammar, G.; Khalfaoui, W.; Oheix, T.; Yvon, A.; Collard, E.; Cayrel, F.; Alquier, D.

    2015-11-01

    Critical issues need to be overcome to produce high performance Schottky diodes on gallium nitride (GaN). To activate dopant, high temperature thermal treatments are required but damage GaN surface where hexagonal pits appear and prevent any device processing. In this paper, we investigated the efficiency of cap-layers on GaN during thermal treatments to avoid degradation. Aluminum nitride (AlN) and silicon oxide (SiOx) were grown on GaN by direct current reactive magnetron sputtering and plasma-enhanced chemical vapor deposition, respectively. AlN growth parameters were studied to understand their effect on the grown layers and their protection efficiency. Focused ion beam was used to measure AlN layer thickness. Crystalline quality and exact composition were verified using X-ray diffraction and energy dispersive X-ray spectroscopy. Two types of rapid thermal annealing at high temperatures were investigated. Surface roughness and pits density were evaluated using atomic force microscopy and scanning electron microscopy. Cap-layers wet etching was processed in H3PO4 at 120 °C for AlN and in HF (10%) for SiOx. This work reveals effective protection of GaN during thermal treatments at temperatures as high as 1150 °C. Low surface roughness was obtained. Furthermore, no hexagonal pit was observed on the surface.

  16. One-Pot dry chemo-mechanical deconstruction for bioethanol production from sugarcane bagasse.

    PubMed

    Sambusiti, C; Licari, A; Solhy, A; Aboulkas, A; Cacciaguerra, T; Barakat, A

    2015-04-01

    The aim of this study was the application of an innovative dry chemo-mechanical pretreatment using different mechanical stresses to produce bioethanol from sugarcane bagasse (SB). The effect of different milling methods on physicochemical composition, enzymatic hydrolysis, bioethanol production and energy efficiency was also evaluated. SB was pretreated with NaOH and H3PO4 at high materials concentration (5 kg/L). Results indicate that vibratory milling (VBM) was more effective in the reduction of particles size and cellulose crystallinity compared to centrifugal (CM) and ball (BM) milling. NaOH pretreatment coupling to BM and VBM was preferred to enhance glucose yields and bioethanol production, while CM consumed less energy compared to BM and VBM. Moreover, the highest energy efficiency (?=0.116 kg glucose/kWh) was obtained with NaOH-CM. Therefore, the combination of dry NaOH and CM appears the most suitable and interesting pretreatment for the production of bioethanol from SB. PMID:25656863

  17. Influence of variously functionalized SBA-15 fillers on conductivity and electrochemical properties of PBI composite membranes for high temperature polymer fuel cells

    NASA Astrophysics Data System (ADS)

    Angioni, S.; Villa, D. C.; Cattaneo, A. S.; Mustarelli, P.; Quartarone, E.

    2015-10-01

    The use of inorganic fillers is an interesting strategy to improve the electrochemical performances of PBI membranes for application as electrolytes in HT-PEMFCs. Here, we prepared several mesoporous silica (SBA-15) based hybrids, functionalised with different moieties, namely acidic (SO3H-), basic (NH2-), and amphoteric (SO3H-NH2) units. The electrochemical properties of the resulting electrolytes were investigated in terms of proton transport and functional tests by varying the silica functionalization degree in the range 10-70 mol%, as well as the particles loading in the polymer (0-30 wt%). The actual effectiveness of the SBA-15 functionalization process in improving the electrolyte properties was compared with both the unfilled membrane and the one filled with pristine SBA-15. The best conductivity (?90 mS cm-1 at 120 °C, 30%RH) was obtained with PBI composites loaded with 30 wt% of non-functionalized SBA-15. The use of fillers functionalized with acidic, basic of amphoteric groups did not lead to improvements with respect to pure SBA-15. This could be related to the set up of significant interactions between the functionalised fillers and H3PO4, which negatively influence the proton mobility. Encouraging MEA results (power peak >320 mW cm-2) were obtained in case of membranes based on pure SBA-15. These performances make the SBA-15/PBI composites particularly interesting for application in HT-PEMFCs.

  18. 2D ^31P NMR Study of Takagi Group Diffusion in Rb_0.50(ND_4)_0.50D_2PO4 Deuteron Glass

    NASA Astrophysics Data System (ADS)

    Kind, R.; Jeitziner, Ch.; Cereghetti, P. M.; Dolinsek, J.; Blinc, R.; Schmidt, V. H.

    2001-03-01

    Slater proposed that KH_2PO4 has 2 polar and 4 nonpolar (with higher energy E_b) H_2PO4 H-bond configurations. Takagi proposed H_3PO4 and HPO4 groups with still higher energy E_a. Via intra bond H transfer, Takagi pairs form, diffuse independently, and annihilate, allowing H-bond reconfiguration. Our 2D ^31P chemical shift study gives the first direct evidence for Takagi group diffusion. A diffusion path past a D_2PO4 group reverses its D-bonds, which may change it from a polar to a nonpolar group or vice versa. Polar and nonpolar group chemical shifts differ, giving a 3-peak 1D NMR spectrum at 50 K. 2D exchange NMR shows that Takagi group diffusion symmetrizes the D-bonds in about 15 s at 45 K. Temperature-dependent results indicate creation energy E_a=81 meV, and diffusion step energy E_b=12 meV in a fractal energy landscape.

  19. Highly proton-conductive thermally rearranged polybenzoxazole for medium-temperature and low-humidity polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Lee, Chang Hyun; Lee, Young Moo

    2014-02-01

    Here a new membrane design concept to improve proton conductivity and to maintain a constant acid doping level for an extended period of time for medium-temperature and low-humidity polymer electrolyte fuel cells (MT/LH-PEFC) is presented. A polymer electrolyte membrane is prepared via thermal rearrangement of hydroxyl-containing polyimide (HPI) precursor membranes over 350 °C, followed by subsequent acid-impregnation. The thermal treatment for 1 h converts HPI into a thermally rearranged polybenzoxazole (TR-PBO) membrane with high surface area, similar to zeolites. The microporous structure and the basic sites (-Cdbnd N-) in benzoxazole moieties contribute to the stable impregnation of small acidic molecules (e.g., HCl, HNO3, H3PO4, and HPF6) in large quantities within the polymer matrix. The acid-doping level decreases with the increasing size of acidic dopants. TR-PBO impregnated using HCl with the smallest radius has a much higher doping level and excellent proton conductivity (1.60 × 10-1 S cm-1 at 130 °C and RH 28%) when compared with PBI (6.59 × 10-2 S cm-1 at the same conditions). Different from a common acid-doped PBI system, the acid-doped TR-PBO membranes do not exhibit a severe acid leaching even in repeated heating and cooling cycles between 90 and 130 °C.

  20. Growth and characterization of electrodeposited Na 0.45VOPO 4, 1.58H 2O materials

    NASA Astrophysics Data System (ADS)

    Bououd, S.; El Hourch, A.; El Kacemi, K.; Guessous, A.; Pradel, A.; Ribes, M.

    2011-12-01

    The paper reports on a new and original way to prepare sodium vanadophosphate by using the electrochemical oxidation of vanadyl ions in H 3PO 4 solution to produce a deposit onto the electrode. Such a way insured an intimate mixing of the component elements in the solution allowing finer particles and high purity materials to be produced by rapid homogenous nucleation. The experimental conditions to obtain a pure phase are described in the paper. The main determining parameter is the solution pH which had to be adjusted at 1.9 or 2.0 with NaOH. A mixture of sodium vanadophosphate and V 2O 5, 0.5H 2O was obtained for higher pH = 2.2. A series of experiments including an X-ray diffraction study, thermogravimetric analysis, transmission electron microscopy and infrared spectroscopy investigation helped in determining the exact chemical formula of the obtained phase, i.e. Na 0.45VOPO 4, 1.58H 2O. The phase exhibits an orthorhombic structure with a = 8.85 Å, b = 9.01 Å and c = 13.02 Å.

  1. 234Th analysis of marine sediments via extraction chromatography and liquid scintillation counting.

    PubMed

    Nour, Svetlana; Burnett, William C; Horwitz, E Philip

    2002-08-01

    234Th is widely used as a natural tracer for study of biological mixing and particle scavenging processes in the ocean. This naturally occurring nuclide serves this purpose due to its convenient half-life (24.1 days), constant rate of production from 238U dissolved in seawater, and its strong tendency to attach to particles in seawater. As a beta/gamma emitter, 234Th may be determined using low-level gas-flow proportional counting, gamma spectrometry, and liquid scintillation counting (LSC). We describe here a technique which combines Cerenkov counting to evaluate 234Th (via 234Pa) with LSC alpha counting of 230Th added to the samples as a yield tracer. Our separation approach is based on a sample preparation procedure for marine sediments using nitric acid leaching in a "hot block", and extraction chromatography (TEVA x Resin) for Th isolation. Samples are counted in plastic LSC vials, using Ultima Gold AB cocktail, in 1 M H3PO4 media. A series of sediment samples spiked with known amounts of 234Th yielded activities within a few percent of the anticipated values. PMID:12150283

  2. Damage-free back channel wet-etch process in amorphous indium-zinc-oxide thin-film transistors using a carbon-nanofilm barrier layer.

    PubMed

    Luo, Dongxiang; Zhao, Mingjie; Xu, Miao; Li, Min; Chen, Zikai; Wang, Lang; Zou, Jianhua; Tao, Hong; Wang, Lei; Peng, Junbiao

    2014-07-23

    Amorphous indium-zinc-oxide thin film transistors (IZO-TFTs) with damage-free back channel wet-etch (BCE) process were investigated. A carbon (C) nanofilm was inserted into the interface between IZO layer and source/drain (S/D) electrodes as a barrier layer. Transmittance electron microscope images revealed that the 3 nm-thick C nanofilm exhibited a good corrosion resistance to a commonly used H3PO4-based etchant and could be easily eliminated. The TFT device with a 3 nm-thick C barrier layer showed a saturated field effect mobility of 14.4 cm(2) V(-1) s(-1), a subthreshold swing of 0.21 V/decade, an on-to-off current ratio of 8.3 × 10(10), and a threshold voltage of 2.0 V. The favorable electrical performance of this kind of IZO-TFTs was due to the protection of the inserted C to IZO layer in the back-channel-etch process. Moreover, the low contact resistance of the devices was proved to be due to the graphitization of the C nanofilms after annealing. In addition, the hysteresis and thermal stress testing confirmed that the usage of C barrier nanofilms is an effective method to fabricate the damage-free BCE-type devices with high reliability. PMID:24969359

  3. Heat of hydration of double-shell slurry feed grouts

    SciTech Connect

    Lokken, R.O.

    1992-12-01

    Samples of double-shell slurry feed (DSSF) grout (used in solidifying the waste stored in DS tanks at Hanford) were prepared and tested in adiabatic calorimeters to determine the effect of waste concentration and dry blend variations on the heat of hydration. Changes in DSSF waste concentration had the greatest impact on the overall heat of hydration of the grouts. Grouts prepared with dilute (100 times) DSSF had temperature rises up to 37 C less than with grouts prepared that for undiluted DSSF (15 C vs 52 C). All the grouts prepared with undiluted DSSF had temperature rises that exceeded 45 C. Partial neutralization of the DSSF with acids resulted in delayed reactions and lower temperature rises than that occurring in the reference grout. The temperature rise of a DSSF grout prepared with waste partially neutralized with HCl was 28 C after 300 hr hydration. Temperature rise for a grout made with DSSF partially neutralized with H3PO4 was 43 C. These values compare with a temperature rise of >52 C for a grout made with untreated DSSF. Decreasing the mix ratio from 9 lb/gal to 7.5 lb/gal did not significantly reduce the adiabatic temperature rise of grouts prepared with partially neutralized DSSF waste.

  4. Phosphorus-modified tungsten nitride/reduced graphene oxide as a high-performance, non-noble-metal electrocatalyst for the hydrogen evolution reaction.

    PubMed

    Yan, Haijing; Tian, Chungui; Wang, Lei; Wu, Aiping; Meng, Meichen; Zhao, Lu; Fu, Honggang

    2015-05-18

    Phosphorus-modified tungsten nitride/reduced graphene oxide (P-WN/rGO) is designed as a high-efficient, low-cost electrocatalyst for the hydrogen evolution reaction (HER). WN (ca. 3?nm in size) on rGO is first synthesized by using the H3[PO4(W3O9)4] cluster as a W source. Followed by phosphorization, the particle size increase slightly to about 4?nm with a P content of 2.52?at?%. The interaction of P with rGO and WN results in an obvious increase of work function, being close to Pt metal. The P-WN/rGO exhibits low onset overpotential of 46?mV, Tafel slope of 54?mV?dec(-1), and a large exchange current density of 0.35?mA?cm(-2) in acid media. It requires overpotential of only 85?mV at current density of 10?mA?cm(-2), while remaining good stability in accelerated durability testing. This work shows that the modification with a second anion is powerful way to design new catalysts for HER. PMID:25824611

  5. Optimization of dilute acid hydrolysis of Enteromorpha

    NASA Astrophysics Data System (ADS)

    Feng, Dawei; Liu, Haiyan; Li, Fuchao; Jiang, Peng; Qin, Song

    2011-11-01

    Acid hydrolysis is a simple and direct way to hydrolyze polysaccharides in biomass into fermentable sugars. To produce fermentable sugars effectively and economically for fuel ethanol, we have investigated the hydrolysis of Enteromorpha using acids that are typically used to hydrolyze biomass: H2SO4, HCl, H3PO4 and C4H4O4 (maleic acid). 5%(w/w) Enteromorpha biomass was treated for different times (30, 60, and 90 min) and with different acid concentrations (0.6, 1.0, 1.4, 1.8, and 2.2%, w/w) at 121°C. H2SO4 was the most effective acid in this experiment. We then analyzed the hydrolysis process in H2SO4 in detail using high performance liquid chromatography. At a sulfuric acid concentration of 1.8% and treatment time of 60 min, the yield of ethanol fermentable sugars (glucose and xylose) was high, (230.5 mg/g dry biomass, comprising 175.2 mg/g glucose and 55.3 mg/g xylose), with 48.6% of total reducing sugars being ethanol fermentable. Therefore, Enteromorpha could be a good candidate for production of fuel ethanol. In future work, the effects of temperature and biomass concentration on hydrolysis, and also the fermentation of the hydrolysates to ethanol fuel should be focused on.

  6. Chemical separation and mass spectrometry of Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial materials using thermal ionization mass spectrometry.

    PubMed

    Yamakawa, Akane; Yamashita, Katsuyuki; Makishima, Akio; Nakamura, Eizo

    2009-12-01

    A sequential chemical separation technique for Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial silicate rocks was developed for precise and accurate determination of elemental concentration by the isotope dilution method (ID). The technique uses a combination of cation-anion exchange chromatography and Eichrom nickel specific resin. The method was tested using a variety of matrixes including bulk meteorite (Allende), terrestrial peridotite (JP-1), and basalt (JB-1b). Concentrations of each element was determined by thermal ionization mass spectrometry (TIMS) using W filaments and a Si-B-Al type activator for Cr, Fe, Ni, and Zn and a Re filament and silicic acid-H3PO4 activator for Cu. The method can be used to precisely determine the concentrations of these elements in very small silicate samples, including meteorites, geochemical reference samples, and mineral standards for microprobe analysis. Furthermore, the Cr mass spectrometry procedure developed in this study can be extended to determine the isotopic ratios of 53Cr/52Cr and 54Cr/52Cr with precision of approximately 0.05epsilon and approximately 0.10epsilon (1epsilon = 0.01%), respectively, enabling cosmochemical applications such as high precision Mn-Cr chronology and investigation of nucleosynthetic isotopic anomalies in meteorites. PMID:19886654

  7. Preparation of a specific bamboo based activated carbon and its application for ciprofloxacin removal.

    PubMed

    Wang, Y X; Ngo, H H; Guo, W S

    2015-11-15

    The studied bamboo based activated carbon (BbAC) with high specific surface area (SSA) and high micro pore volume was prepared from bamboo scraps by the combined activation of H3PO4 and K2CO3. The BbAC was characterized based on the N2 adsorption isotherm at 77K. The results showed that the SSA and pore volume of BbAC increased with increasing impregnation ratio and reached maxima at the impregnation ratio of 3:1 at 750°C. Under these optimal conditions, the BbAC obtained could have a maximum SSA of 2237 m(2)/g and a maximum total pore volume of 1.23 cm(3)/g with the micro pore ratio of more than 90%. The adsorption performance of ciprofloxacin (CIP) on the BbAC was determined at 298 K. The Langmuir and Freundlich models were employed to describe the adsorption equilibrium and the kinetic data were fitted by pseudo first-order and pseudo second-order kinetic models. The results showed that the Langmuir model and the pseudo second-order kinetic model presented better fittings for the adsorption equilibrium and kinetics data, respectively. The maximum adsorption amount of CIP (613 mg/g) on the BbAC was much higher than the report in the literature. Conclusively, the BbAC could be a promising adsorption material for CIP removal from water. PMID:26150305

  8. Bulk filling of Class II cavities with a dual-cure composite: Effect of curing mode and enamel etching on marginal adaptation

    PubMed Central

    Bortolotto, Tissiana; Roig, Miguel; Krejci, Ivo

    2014-01-01

    Objectives: This study attempted to find a simple adhesive restorative technique for class I and II cavities on posterior teeth. Study Design: The tested materials were a self-etching adhesive (Parabond, Coltène/Whaledent) and a dual-cure composite (Paracore, Coltène/Whaledent) used in bulk to restore the cavities. Class II MO cavities were performed and assigned to 4 groups depending on the orthophosphoric acid (H3PO4) conditioning of enamel and polymerization method used (chemical or dual). Specimens were subjected to quantitative marginal analysis before and after thermo-mechanical loading. Results: Higher percentages of marginal adaptation at the total margin length, both before and after thermo-mechanical loading, were found in groups in which enamel was etched with phosphoric acid, without significant differences between the chemically and dual-cured modes. The restorations performance was similar on enamel and dentin, obtaining low results of adaptation on occlusal enamel in the groups without enamel etching, the lowest scores were on cervical dentin in the group with no ortophosphoric acid and self-cured. Conclusions: A dual-cure composite applied in bulk on acid etched enamel obtained acceptable marginal adaptation results, and may be an alternative technique for the restoration of class II cavities. Key words:Dual-cure composite, bulk technique, class II restoration, selective enamel etching, marginal adaptation. PMID:25674316

  9. Stability of the anodic growth porous tungsten oxide in different solutions

    NASA Astrophysics Data System (ADS)

    Chai, Y.; Yam, F. K.; Hassan, Z.

    2015-05-01

    This article presents the study of the stability of the anodic growth porous tungsten oxide (WO3) film in different solutions. As-anodized films are relatively stable in acidic electrolytes like sulphuric acid (H2SO4), hydrochloric acid (HCl) but not in oxalic acid. In higher pH solution, rate of dissolution of the WO3 film is higher. Annealing at 400 °C for 2 h transform the as-grown sample from amorphous phase to the crystalline phase and this significantly improve the stability of the film in high pH solution. Photocurrent measurements reveal that there is no significant difference of the electrolyte used (0.5 M H2SO4, 0.33 M H3PO4, 0.1 M sodium sulfate (Na2SO4)) on the photocurrent. As-annealed films exhibit good stablility for the long photoelectrochemical (PEC) measurements (1700 s) in 0.5 M H2SO4 and 0.1 M Na2SO4. There is no effect on the photocurrent for the variation of the concentration of the acidic solution (H2SO4). However, lower photocurrent was obtained as the concentration of Na2SO4 was increased.

  10. Osteoconductivity and Hydrophilicity of TiO2 Coatings on Ti Substrates Prepared by Different Oxidizing Processes

    PubMed Central

    Yamamoto, Dai; Kawai, Ikki; Kuroda, Kensuke; Ichino, Ryoichi; Okido, Masazumi; Seki, Azusa

    2012-01-01

    Various techniques for forming TiO2 coatings on Ti have been investigated for the improvement of the osteoconductivity of Ti implants. However, it is not clear how the oxidizing process affects this osteoconductivity. In this study, TiO2 coatings were prepared using the following three processes: anodizing in 0.1 M H3PO4 or 0.1 M NaOH aqueous solution; thermal oxidation at 673?K for 2 h in air; and a two-step process of anodizing followed by thermal oxidation. The oxide coatings were evaluated using SEM, XRD, and XPS. The water contact angle on the TiO2 coatings was measured as a surface property. The osteoconductivity of these samples was evaluated by measuring the contact ratio of formed hard tissue on the implanted samples (defined as the RB-I value) after 14?d implantation in rats' tibias. Anatase was formed by anodizing and rutile by thermal oxidation, but the difference in the TiO2 crystal structure did not influence the osteoconductivity. Anodized TiO2 coatings were hydrophilic, but thermally oxidized TiO2 coatings were less hydrophilic than anodized TiO2 coatings because they lacked in surface OH groups. The TiO2 coating process using anodizing without thermal oxidation gave effective improvement of the osteoconductivity of Ti samples. PMID:23316128

  11. Anodic titanium oxide as immobilized photocatalyst in UV or visible light devices.

    PubMed

    Diamanti, M V; Ormellese, M; Marin, E; Lanzutti, A; Mele, A; Pedeferri, M P

    2011-02-28

    Titanium anodizing can be a powerful technique to generate photoactive oxides, strongly adherent to the metallic substrate, and to modify their chemical composition by inducing doping effects. This work investigates the photocatalytic behavior of differently obtained anodic TiO(2) films under UV and visible light irradiation, so as to define the best treatment for wastewaters purifiers. Anodizing was performed in H(3)PO(4) and H(2)SO(4) mixtures or in fluoride containing electrolytes. Morphology, elemental composition and crystal structure of the anodic films were characterized by XDR, GDOES and SEM. When amorphous oxides were obtained, an annealing treatment was used to promote the formation of anatase crystals. Annealing was also performed in nitrogen atmosphere to induce nitrogen doping. The photocatalytic efficiency of anatase-enriched TiO(2) was investigated in rhodamine B photodegradation. Doping was induced not only by annealing but also directly by anodizing, and generated photoactivity in both the UV and Vis components of light. PMID:21242031

  12. Advanced light-scattering materials: Double-textured ZnO:B films grown by LP-MOCVD

    NASA Astrophysics Data System (ADS)

    Addonizio, M. L.; Spadoni, A.; Antonaia, A.

    2013-12-01

    Double-textured ZnO:B layers with enhanced optical scattering in both short and long wavelength regions have been successfully fabricated using MOCVD technique through a three step process. Growth of double-textured structures has been induced by wet etching on polycrystalline ZnO surface. Our double-layer structure consists of a first ZnO:B layer wet etched and subsequently used as substrate for a second ZnO:B layer deposition. Polycrystalline ZnO:B layers were etched by utilizing diluted solutions of fluoridic acid (HF), chloridric acid (HCl) and phosphoric acid (H3PO4) and their effect on surface morphology modification was systematically investigated. The morphology of the second deposited ZnO layer strongly depended on the surface properties of the etched ZnO first layer. Growth of cauliflower-like texture was induced by protrusions presence on the HCl etched surface. Optimized double-layer structure shows a cauliflower-like double texture with higher RMS roughness and increased spectral haze values in both short and long wavelength regions, compared to conventional pyramidal-like single texture. Furthermore, this highly scattering structure preserves excellent optical and electrical properties.

  13. Determination of the ?13C of dissolved inorganic carbon in water; RSIL lab code 1710

    USGS Publications Warehouse

    Singleton, Glenda L.; Revesz, Kinga; Coplen, Tyler B.

    2012-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1710 is to present a method to determine the ?13C of dissolved inorganic carbon (DIC) of water. The DIC of water is precipitated using ammoniacal strontium chloride (SrCl2) solution to form strontium carbonate (SrCO3). The ?13C is analyzed by reacting SrCO3 with 100-percent phosphoric acid (H3PO4) to liberate carbon quantitatively as carbon dioxide (CO2), which is collected, purified by vacuum sublimation, and analyzed by dual inlet isotope-ratio mass spectrometry (DI-IRMS). The DI-IRMS is a DuPont double-focusing mass spectrometer. One ion beam passes through a slit in a forward collector and is collected in the rear collector. The other measurable ion beams are collected in the front collector. By changing the ion-accelerating voltage under computer control, the instrument is capable of measuring mass/charge (m/z) 45 or 46 in the rear collector and m/z 44 and 46 or 44 and 45, respectively, in the front collector. The ion beams from these m/z values are as follows: m/z 44 = CO2 = 12C16O16O, m/z 45 = CO2 = 13C16O16O primarily, and m/z 46 = CO2 = 12C16O18O primarily. The data acquisition and control software calculates ?13C values.

  14. Selective enrichment of catecholamines using iron oxide nanoparticles followed by CE with UV detection.

    PubMed

    Lin, Tzu-Hsiang; Lu, Chi-Yu; Tseng, Wei-Lung

    2013-01-01

    This study examines the use of unmodified magnetite nanoparticles (Fe(3)O(4) NPs) for selective extraction and enrichment of the catecholamines dopamine (DA), noradrenaline (NE), and adrenaline (E), prior to analysis using capillary electrophoresis with UV detection. Coordination between Fe(3+) on-the-surface Fe(3)O(4) NPs and the catechol moiety of catecholamines enables Fe(3)O(4) NPs to capture catecholamines from an aqueous solution. We obtained maximum loading of catecholamines on the NP surface by adjusting the pH of the solution to 7.0. In addition, catecholamine loading on the Fe(3)O(4) NPs increased in conjunction with NP concentrations. H(3)PO(4) was found to be efficient for the removal of adsorbed catecholamines on the NP surface. Adding 1.2% poly(diallyldimethylammonium chloride) to the background electrolyte resulted in a baseline separation of the liberated catecholamines within 20 min. Under optimal extraction and separation conditions, the limit of detections at a S/N ratio of 3 for E, NE, and DA were 9, 8, and 10 nM, respectively. Significantly, the combination of a phenylboronate-containing spin column and the proposed method was successfully applied to the determination of NE and DA in human urine and NE in Portulaca oleracea L. leaves. PMID:23161197

  15. Polybenzimidazole-multiwall carbon nanotubes composite membranes for polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Guerrero Moreno, Nayibe; Gervasio, Dominic; Godínez García, Andrés; Pérez Robles, Juan Francisco

    2015-12-01

    Polymer membranes are prepared as a composite of polybenzimidazole and non-functionalized multiwall carbon nanotubes (PBI-CNT) and polybenzimidazole (PBI) only. Each is doped with H3PO4 (PA) and used as a proton exchange membrane (PEM) as the electrolyte in a fuel cell. The proton conductivities at 180 °C for the doped PBI membrane (PBIPA) and the doped PBI-CNT membrane (PBICNTPA) are 6.3 × 10-2 and 7.4 × 10-2 Scm-1 respectively. A single fuel cell having these membranes as electrolyte has a Pt catalyzed hydrogen gas fed anode and a similar oxygen cathode without humidification of feed gases; the cell with the PBICNTPA membrane has higher open circuit voltage (0.96 V) than that with a PBIPA membrane (0.8 V) at 180 °C. The mechanical stability of the membrane improves with CNTs addition. The tensile strength of the composite PBI-CNT membrane with 1 wt.% CNTs loading is 32% higher and the Young's Modulus is 147% higher than the values for a membrane of PBI alone. The improvement in conductivity and mechanical properties in the composite membrane due to the CNT addition indicates that a PBI-CNT membrane is a good alternative as a membrane electrolyte in a PEMFC.

  16. Characterization of the carbonaceous materials obtained from different agro-industrial wastes.

    PubMed

    Ensuncho-Muñoz, A E; Carriazo, J G

    2015-01-01

    This paper reports the preparation and characterization of carbonaceous materials obtained from three types of vegetable wastes provided by agricultural industries. Soft carbonization (280°C) and H3PO4-activation procedures were used to convert the agricultural wastes to carbon powders with high adsorbent capacities. This process is excellent for eliminating and exploiting the huge masses (many tons) of vegetable residues remaining after each harvest every year in several Colombian agro-industries. The powders were characterized by X-ray diffraction (XRD), IR spectroscopy, scanning electron microscopy (SEM), and N2-adsorption isotherms. XRD and IR verified the formation of carbons, and SEM showed small particles (20-500?µm) with characteristic morphology for each type of residue used and abundant cavities of different sizes. The N2-adsorption analyses showed that the carbons had high adsorption capacities with important surface area values and large pore volumes. The use of the activated carbonaceous materials as adsorbent of azo dyes (allura red and sunset yellow) from aqueous solutions was evaluated. The results showed a good adsorption capacity indicating the potentiality of these materials as pollutant adsorbents in food industry wastewaters. These results indicate that these powders can be used as potential adsorbents for different gaseous or liquid pollutants. PMID:25189634

  17. Biaxially stretchable supercapacitors based on the buckled hybrid fiber electrode array.

    PubMed

    Zhang, Nan; Zhou, Weiya; Zhang, Qiang; Luan, Pingshan; Cai, Le; Yang, Feng; Zhang, Xiao; Fan, Qingxia; Zhou, Wenbin; Xiao, Zhuojian; Gu, Xiaogang; Chen, Huiliang; Li, Kewei; Xiao, Shiqi; Wang, Yanchun; Liu, Huaping; Xie, Sishen

    2015-08-01

    In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g(-1). H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times. PMID:26136109

  18. Gadolinium-hydrogen ion exchange of zirconium phosphate

    NASA Technical Reports Server (NTRS)

    Liu, D. C.; Power, J. L.

    1972-01-01

    The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

  19. Modeling for CO poisoning of a fuel cell anode

    NASA Technical Reports Server (NTRS)

    Dhar, H. P.; Kush, A. K.; Patel, D. N.; Christner, L. G.

    1986-01-01

    Poisoning losses in a half-cell in the 110-190 C temperature range have been measured in 100 wt pct H3PO4 for various mixtures of H2, CO, and CO2 gases in order to investigate the polarization loss due to poisoning by CO of a porous fuel cell Pt anode. At a fixed current density, the poisoning loss was found to vary linearly with ln of the CO/H2 concentration ratio, although deviations from linearity were noted at lower temperatures and higher current densities for high CO/H2 concentration ratios. The surface coverages of CO were also found to vary linearly with ln of the CO/H2 concentration ratio. A general adsorption relationship is derived. Standard free energies for CO adsorption were found to vary from -14.5 to -12.1 kcal/mol in the 130-190 C temperature range. The standard entropy for CO adsorption was found to be -39 cal/mol per deg K.

  20. Changes in 4-vinylsyringol and other phenolics during rapeseed oil refining.

    PubMed

    Kralji?, Klara; Škevin, Dubravka; Bariši?, Lidija; Kova?evi?, Monika; Obranovi?, Marko; Jur?evi?, Ivana

    2015-11-15

    The aim of the present study was to examine changes in phenolic compounds during refining of rapeseed oil. In crude rapeseed oil, 4-vinylsyringol (canolol) is the dominant phenolic compound, accounting for 85% of total phenolics. Refining decreased the total amount of phenolic compounds by 90%. NMR and MS analyses of edible rapeseed oil phenolic extracts identified 4-vinylsyringol dimer as the dominant phenolic compound. This phenolic compound appears to form through acid-catalyzed dimerization-aromatic substitution of 4-vinylsyringol monomers. Analysis of rapeseed oils from different stages of the refining process suggest that 4-vinylsyringol dimer forms during the neutralization phase, when H3PO4 acts as a catalyst, or during bleaching, when acid-activated bleaching earth acts as the catalyst. Whether 4-vinylsyringol forms during one or the other phase appears to depend on the phospholipid content of the crude oil. These insights may be useful for designing rapeseed oil refining processes that maximize levels of 4-vinylsyringol dimer. PMID:25977022

  1. Determination of arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid in cereals by hydride generation atomic fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Matos Reyes, M. N.; Cervera, M. L.; Campos, R. C.; de la Guardia, M.

    2007-09-01

    A fast, sensitive and simple non-chromatographic analytical method was developed for the speciation analysis of toxic arsenic species in cereal samples, namely rice and wheat semolina. An ultrasound-assisted extraction of the toxic arsenic species was performed with 1 mol L - 1 H 3PO 4 and 0.1% (m/v) Triton XT-114. After extraction, As(III), As(V), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) concentrations were determined by hydride generation atomic fluorescence spectrometry using a series of proportional equations corresponding to four different experimental reduction conditions. The detection limits of the method were 1.3, 0.9, 1.5 and 0.6 ng g - 1 for As(III), As(V), DMA and MMA, respectively, expressed in terms of sample dry weight. Recoveries were always greater than 90%, and no species interconversion occurred. The speciation analysis of a rice flour reference material certified for total arsenic led to coherent results, which were also in agreement with other speciation studies made on the same certified reference material.

  2. Hydrothermally mixed hydroxyapatite-multiwall carbon nanotubes composite coatings on biomedical alloys by electrophoretic deposition.

    PubMed

    Ustundag, C B; Avciata, O; Kaya, F; Kaya, C

    2013-02-14

    Hydroxyapatite (HA) coatings have been used to improve biological and mechanical fixation of metallic prosthesis. Because of extraordinary features of carbon nanotubes (CNTs), they have a lot of facilities, such as extremely strong nanoreinforcement materials for composites. HA powders were synthesized and mixed with multiwalled carbon nanotubes (MWCNTs) by a hydrothermal process. Calcium acetate (Ca (CH(3)COO)(2)) and phosphoric acid (H(3)PO(4)) were used as starting materials for synthesizing nano-HA powders. HA-MWCNTs were treated together hydrothermally at 200 °C for 2 h to synthesize nano-HA powders mixed homogeneously with MWCNTs. Cathodic deposits were obtained on Ti-based alloys using suspensions containing nano-HA and MWCNTs dispersed in n-butanol solvent. It was shown that MWCNTs interacted with HA powders during hydrothermal processing, and therefore, they can easily be dispersed within aqueous-based suspensions. It was also shown that hydrothermal surface modification of MWCNTs with functional groups was achievable, which was a significant step toward eliminating nonwetting surface behavior of MWCNTs, resulting in obtaining homogeneous dispersion of them in liquids. PMID:22780563

  3. Development of a quinazoline-based chelating ligand for zinc ion and its application to validation of a zinc-ion-coordinated compound.

    PubMed

    Yamada, Hiroshi; Shirai, Akina; Kato, Keisuke; Kimura, Junko; Ichiba, Hideaki; Yajima, Takehiko; Fukushima, Takeshi

    2010-06-01

    A novel fluorescent chelating ligand, 2,4-[bis-(2-hydroxy-3-methoxybenzylidene)]-dihydrazinoquinazoline (HBQZ), was synthesized, and the fluorescence characteristics of its complex with metal ions were investigated. Among the 36 different metal ions tested in this study, it was found that HBQZ emits intense fluorescence at 506 nm with an excitation wavelength of 414 nm in the presence of Zn2+. The fluorescence intensity was almost constant in the pH range 3.5-10.5. Complexes of other metal ions with HBQZ did not show fluorescence, and the detection limit of Zn2+ was approximately 250 nM (16 ppb). The proposed method was applied to the validation test of a bioactive compound containing Zn2+ in its structure--an antibacterial and antifungal reagent, zinc pyrithione (ZnPT). In order to effectively release Zn2+ from ZnPT, a pretreatment procedure involving heating with H3PO4 at 100 degrees C for 60 min was adopted. Under these conditions, a linear calibration curve was obtained in the ZnPT concentration range of 0.79-15.7 microM (0.25-5.0 ppm); the correlation coefficient and the relative standard deviation were 0.996 and within 3.1% (n=5), respectively. PMID:20523005

  4. Surface phenomena of HA/TiN coatings on the nanotubular-structured beta Ti-29Nb-5Zr alloy for biomaterials

    NASA Astrophysics Data System (ADS)

    Kim, Eun-Ju; Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A.

    2012-01-01

    Surface phenomena of HA/TiN coatings on the nanotubular-structured beta Ti-29Nb-5Zr alloy for biomaterials have been investigated by several experimental methods. The nanotubular structure was formed by anodizing the Ti-29Nb-5Zr alloy in 1 M H3PO4 electrolytes with 1.0 wt.% NaF at room temperature. Hydroxyapatite (HA)/titanium nitride (TiN) films were deposited on Ti-29Nb-5Zr alloy specimens using a magnetron sputtering system. The HA target was made of human tooth-ash by sintering at 1300 °C for 1 h, and the HA target had an average Ca/P ratio of 1.9. The HA/TiN depositions were performed, using the pure HA target, on Ti-29Nb-5Zr alloy following the initial deposition of a TiN buffer layer coating. Microstructures and nanotubular morphology of the coated alloy specimens were examined by FE-SEM, EDX, XRD, and XPS. The Ti-29Nb-5Zr alloy substrate had small grain size and preferred orientation along the drawing direction. The HA/TiN coating was stable with a uniform morphology at the tips of the nanotubes.

  5. Investigation of the growth and local stoichiometric point group symmetry of titania nanotubes during potentiostatic anodization of titanium in phosphate electrolytes

    NASA Astrophysics Data System (ADS)

    Cummings, F. R.; Muller, T. F. G.; Malgas, G. F.; Arendse, C. J.

    2015-10-01

    Potentiostatic anodization of commercially pure, 50 ?m-thick titanium (Ti) foil was performed in aqueous, phosphate electrolytes at increasing experimental timeframes at a fixed applied potential for the synthesis of titania nanotube arrays (TNAs). High resolution scanning electron microscopy images, combined with energy dispersive spectroscopy and x-ray diffraction spectra reveal that anodization of the Ti foil in a 1 M NaF+0.5 M H3PO4 electrolyte for 4 h yields a titanate surface with pore diameters ranging between 100 and 500 nm. The presence of rods on the Ti foil surface with lengths exceeding 20 ?m and containing high concentrations of phosphor on the exterior was also detected at these conditions, along with micro-sized coral reef-like titanate balls. We propose that the formation of these structures play a major role during the anodization process and impedes nanotube growth during the anodization process. High spatially resolved scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) performed along the length of a single anodized TiO2 nanotube reveals a gradual evolution of the nanotube crystallinity, from a rutile-rich bottom to a predominantly anatase TiO2 structure along its length.

  6. Carbon molecular sieves from carbon cloth: Influence of the chemical impregnant on gas separation properties

    NASA Astrophysics Data System (ADS)

    Rodríguez-Blanco, G.; Giraldo, L.; Moreno-Piraján, J. C.

    2010-06-01

    Carbon materials with molecular sieve properties (CMS) were prepared by pyrolysis of cotton fabrics by chemical activation procedures. To evaluate the changes in the chemical and textural properties, the impregnants AlCl 3, ZnCl 2 and H 3PO 4 were used at 1123 K. The materials were characterized using adsorption of nitrogen and carbon dioxide, TPD, and immersion calorimetry in C 6H 6. Adsorption kinetics of O 2, N 2, CO 2, CH 4, C 3H 8 and C 3H 6 were measured in all the prepared materials to determine their behaviour as molecular sieves. The results confirm that the chemical used as impregnant has a significant effect on the resulting CMS separation properties. All materials exhibit microporosity and low oxygen surface group contents; however, the sample impregnated with zinc chloride, with an immersion enthalpy value of 66.4 J g -1 in benzene, exhibits the best performance in the separation of CH 4-CO 2 and C 3H 8-C 3H 6 at 273 K.

  7. Quality control of tuirejieduling granules using high-performance liquid chromatography fingerprint method and simultaneous determination of four main active ingredients

    PubMed Central

    Yang, Aixia; Wang, Xiaoxian; Xiong, Chaomei; Chen, Jing; Ruan, Jinlan

    2013-01-01

    Background: The Tuirejieduling granule is a compound preparation made from four kinds of Chinese medicines. It is effective for anti-inflammation, antivirus, defervescence and anti-bacterium; however, its quality control standards have remained unknown. Objective: To establish a simple and accurate fingerprint method for quality control of the Tuirejieduling granule. Materials and Methods: The methanol extract of the Tuirejieduling granule was used for the fingerprint analysis and the four selected active ingredients (epigoitrin, phillyrin, saikosaponin A and glycyrrhetinic acid) in the extract were determined. The fingerprint method was performed on an Amethyst C18-P chromatography column by gradient elution with acetonitrile and aqueous phase (containing 0.5% H3PO4 (v/v), pH 3.0). Results: Under the optimal chromatographic condition, twenty peaks were chosen as fingerprint peaks of the Tuirejieduling granules extractions. The similarities of 10 batches of Tuirejieduling granule was more than 0.99. This indicates that the different batches of Tuirejieduling granules were under the consistent quality control. Good linear behaviors over the investigated concentration ranges were obtained with the values of R2 higher than 0.99 for four studied active ingredients. The recoveries for spiked samples were in the range of 96.2–105.5%. The developed method was successfully applied to determine the contents of active constituents in different batches of Tuirejieduling granule. Conclusion: The HPLC fingerprint was proved to be a reliable method for the quality control of Tuirejieduling granule. PMID:23772113

  8. Biosorption of model pollutants in liquid phase on raw and modified rice husks

    NASA Astrophysics Data System (ADS)

    Toniazzo, L.; Fierro, V.; Braghiroli, F.; Amaral, G.; Celzard, A.

    2013-03-01

    We studied the application of rice husk (RH) as a biosorbent and we demonstrated that it can be employed for the treatment of dyeing wastewater streams. RH was obtained from Nile Delta (Egypt) and it was used as received, or after a chemical treatment using HNO3 or NaOH, or after conversion into activated carbon (RH-AC) using H3PO4 as activating agent. A commercial activated carbon GAC 830 provided by NORIT was also tested for comparison purposes. These materials were evaluated by adsorption of methylene blue (MB) with an initial concentration of 20 ppm in an aqueous solution at 30°C. The results showed that alkali-treated and RH-AC were the best sorbents. They got a nearly complete MB removal from water and they had better performance than GAC 830. Therefore, the use of RH for pollutant removal makes this method an environment-friendly option and an economically feasible alternative to treat industrial effluents.

  9. Grafting ligands to direct the self-assembly of Co/Ni2+ substituted polyoxometalate clusters.

    PubMed

    Ritchie, Chris; Boyd, Thomas; Long, De-Liang; Ditzel, Evert; Cronin, Leroy

    2009-03-01

    Four transition metal incorporated phosphotungstates have been synthesized through the reaction of Na(2)WO(4), H(3)PO(4), Co/Ni(NO(3))(2), and the multifunctional amine N,N'-Bis(2-hydroxyethyl) piperazine (bhep). Na(2){MHbhep(H(2)O)(4)}[PW(10)M(2)O(38){Hbhep}(2)] M = Co(2+) (1), and Ni(2+)(2) represent rare examples of complete transition metal chelate encapsulation within a Keggin polyanion. Slight modification of the reaction procedure yielding 1 also yields the two dimensional material (H(2)bhep)(3)Na(4)[Co(4)(H(2)O)(2)(PW(9)O(34))(2)].15H(2)O (3). Finally, the isolation of a phosphotungstate cluster containing 18 Co(2+) ions is achieved through the bridging of two [Co(9)(OH)(3)(H(2)O)(6)(HPO(4))(2)(B-alpha-PW(9)O(34))(3)](16-) clusters by the bhep ligand to form the [{Co(9)(OH)(3)(H(2)O)(3)(HPO(4))(2)(B-alpha-PW(9)O(34))(3)}(2) {C(8)H(18)N(2)O(2)}(3)](32-) dimer (4). The dimerisation process is achieved via the monodentate coordination of the hydroxyl groups from three bhep ligands to each polyanion by displacing the water ligands typically found coordinated to the {Co(9)} core forming a nanoscale cylinder-like capsule capped by two {Co(9)P(5)W(27)} with three BHEP-based ligand spacers. PMID:19421602

  10. Effects of speciation on equilibrium fractionations and rates of oxygen isotope exchange between (PO 4) aq and H 2O

    NASA Astrophysics Data System (ADS)

    O'Neil, James R.; Vennemann, Torsten W.; McKenzie, William F.

    2003-09-01

    The effects of phosphate speciation on both rates of isotopic exchange and oxygen isotope equilibrium fractionation factors between aqueous phosphate and water were examined over the temperature range 70 to 180°C. Exchange between phosphate and water is much faster at low pH than at high pH, an observation that is similar to what has been observed in the analogous sulfate-water system. Oxygen isotope fractionations between protonated species like H 3PO 4 and H 2PO 4- that are dominant at relatively low pH and species like PO 43- and ion pairs like KHPO 4- that are dominant at relatively high pH, range between 5 and 8‰ at the temperatures of the experiments. In aqueous phosphate systems at equilibrium, 18O/ 16O ratios increase with increasing degree of protonation of phosphate. This effect can be explained in part by the relative magnitudes of the dissociation constants of the protonated species. Under equilibrium conditions, carbonate in solution or in solid phases concentrates 18O relative to orthophosphate in solution or in solid phases at all temperatures, supporting the traditional view that biogenic phosphate is precipitated in near oxygen isotope equilibrium with body/ambient aqueous fluids with no attendant vital effects.

  11. Ultrasensitive analysis of lysergic acid diethylamide and its C-8 isomer in hair by capillary zone electrophoresis in combination with a stacking technique and laser induced fluorescence detection.

    PubMed

    Airado-Rodríguez, Diego; Cruces-Blanco, Carmen; García-Campaña, Ana M

    2015-03-25

    This article deals with the development and validation of a novel capillary zone electrophoresis (CZE) with laser induced fluorescence detection method for the analysis of lysergic acid diethylamide (LSD) and its isomer iso-LSD in hair samples. The separation of both analytes has been achieved in less than 13 min in a 72-cm effective length capillary with 75-?m internal diameter. As running buffer 25 mM citrate, pH 6.0 has been employed and separation temperature and voltage of 20 °C and 13 kV respectively, were applied. Field amplified sample injection (FASI) has been employed for on-line sample preconcentration, using ultrapure water containing 117 ?M H3PO4 as optimum injection medium. Injection voltage and time have been optimized by means of experimental design, obtaining values of 7 kV and 15s, respectively. Methylergonovine has been employed as internal standard in order to compensate irreproducibility from electrokinetic injection. The analytical method has been applied to hair samples, previous extraction of the target analytes by ultrasound assisted solid-liquid extraction at 40 °C for 2.5 h, employing acetonitrile as extracting solvent. Linear responses were found for LSD and iso-LSD in matrix-matched calibrations from around 0.400 up to 50.0 pg mg(-1). LODs (3 S/N) in the order of 0.100 pg mg(-1) were calculated for both analytes, obtaining satisfactory recovery percentages for this kind of sample. PMID:25732697

  12. Crystal Structure of 2-Amino-5-Nitropyridinium Dihydrogenphosphate Monophosphoric Acid: Influence of the Polyanion Charge on the Formation of Centrosymmetric Structure

    NASA Astrophysics Data System (ADS)

    Zaccaro, Julien; Bagieu-Beucher, Muriel; Ibanez, Alain; Masse, René

    1996-06-01

    Chemical preparation and structural characterization by single crystal X-ray diffraction are given for the 2-amino-5-nitropyridinium dihydrogenphosphate monophosphoric acid (2A5NPDPP): C5H6N3O+2·H2PO-4·H3PO4. Crystals are monoclinic, space groupP21/nwitha= 16.050(16),b= 8.985(5),c= 8.830(5) Å, ? = 96.86(7)°,V= 1264(2) Å3,Z= 4. The structure was refined toR= 0.050 (RW= 0.056) for 2224 reflections withI? 3?(I). The structural arrangement can be described as inorganic layers of H5P2O-8units separated by infinite organic chains of chromophores. Strong hydrogen bonds maintain a two-dimensional cohesion between phosphate tetrahedra while weaker ones link the organic cations together and to the anionic subnetwork. The influence of the polyanion charge on the symmetry of the cationic packing is discussed with respect to the herringbone structure of the 2-amino-5-nitropyridinium dihydrogenphosphate (2A5NPDP), a nonlinear optical crystal built with the same chromophores.

  13. The performance of phosphorus (P)-doped activated carbon as a catalyst in air-cathode microbial fuel cells.

    PubMed

    Chen, Zhihao; Li, Kexun; Pu, Liangtao

    2014-10-01

    To observe the influence of P-doped activated carbon (AC) in air-cathode microbial fuel cells (MFCs), AC was treated with H3PO4 (1M) at 80°C and 400°C respectively, and then was used as catalyst layer in the air-cathode. The maximum power densities were: 1096±33mW/m(2) (SP2, AC treated at 400°C), 954±36mW/m(2) (SP1, AC treated at 80°C), which were 55%, 35% higher than the control (708±27mW/m(2), untreated AC), respectively. The results of electrochemical impedance spectroscopy (EIS) and the Brunauer-Emmett-Teller (BET) showed that the total resistance was decreased and the pore structure was changed. The analysis of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) demonstrated that P-doped functional group was produced in SP2, which caused the 15% greater power density than SP1 by increasing O2 adsorption. What is more important, the chemically modified method is simple and economical. PMID:25151475

  14. Distributed Bragg reflector based on porous anodic alumina fabricated by pulse anodization

    NASA Astrophysics Data System (ADS)

    Sulka, Grzegorz D.; Hnida, Katarzyna

    2012-02-01

    In this paper, we demonstrate a distributed Bragg reflector (DBR) based on nanoporous anodic aluminum oxide (AAO) formed by pulse anodization. The AAO structure with alternating mild anodized (MA) and hard anodized (HA) layers having different porosities and thereby different refractive indices was fabricated in 0.3 M H2SO4 using potential pulses of 25 and 35 V. The effective refractive index of the HA layers can be tailored by changing the porosity of the HA layers. The porosity of the HA layers can be significantly increased by selective chemical etching of HA segments in 0.52 M H3PO4. Before etching, the porous AAO structure was supported by a polymer nanorod frame. On the selected surface area pores were infiltrated with polymers (polystyrene and PMMA). The designed AAO structure consists of alternating high and low refractive index layers and behaves as a distributed Bragg mirror reflecting light in two different ranges of wavelength. This behavior is extremely important in optical communication lines where two separate spectral bands of high reflectivity in the infrared region are desired.

  15. Adsorptive treatment of brewery effluent using activated Chrysophyllum albidium seed shell carbon.

    PubMed

    Menkiti, Matthew Chukwudi; Aneke, Mathew Chidiebere; Ejikeme, Paul Madus; Onukwuli, Okechukwu Dominic; Menkiti, Nwasinachi Uzoma

    2014-01-01

    Chrysophyllum albidium seed shell, an abundant, biodegradable and inexpensive natural resource was used as a precursor to bioadsorbent production for the removal of suspended and dissolved particles (SDP) from initially coagulated Brewery Effluent (BRE). Influence of key parameters such as contact time, bioadsorbent dose, pH and temperature were investigated using batch mode. The thermal behavior studies were evaluated using Thermogravimetric and Differential scanning calorimetric analyses. The morphological observations and functional groups of the bioadsorbents were determined using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The adsorption equilibrium, thermodynamics and kinetic of SDP adsorption on H3PO4-treated shell and NH4Cl-treated shell were examined at specified temperatures. Equilibrium data sufficiently fitted the Langmuir isotherm model (R (2)?>?0.99; SSE??0.99; SSE?

  16. Rhodamine B removal with activated carbons obtained from lignocellulosic waste.

    PubMed

    da Silva Lacerda, Viviane; López-Sotelo, Juan B; Correa-Guimarães, Adriana; Hernández-Navarro, Salvador; Sánchez-Báscones, Mercedes; Navas-Gracia, Luis M; Martín-Ramos, Pablo; Martín-Gil, Jesús

    2015-05-15

    By-products from the wax production process from carnauba palm (leaves), from the extraction of oil from macauba seeds (endocarp) and from pine nut production (shell) have been assessed for activated carbon production, using H3PO4 or CaCl2 for their chemical activation. The resulting activated charcoals have been thoroughly characterized by elemental and thermal analysis, X-ray diffraction, infrared spectroscopy, electron scanning microscopy and N2 adsorption behavior. Subsequently, their adsorption capacity for the removal of rhodamine B (RhB) from aqueous solutions has been evaluated by studying different parameters: contact time, pH, adsorbent dose, initial dye concentration and solution temperature. The adsorption of RhB followed Freundlich's model in all cases. Kinetic studies indicate that the pseudo-second order model can be used for describing the dynamics of the adsorption process. Thermodynamic parameters have also been evaluated, indicating its endothermic and spontaneous nature. Finally, a preliminary analysis of the impact of cellulose content in the carbon precursor materials has been conducted, by using a mixture of native cellulose with one of the lignocellulosic materials. PMID:25770964

  17. Efficient production of fermentable sugars from oil palm empty fruit bunch by combined use of acid and whole cell culture-catalyzed hydrolyses.

    PubMed

    Li, Qingxin; Ng, Wei Ting; Puah, Sze Min; Bhaskar, Ravindran Vijay; Soh, Loon Siong; Macbeath, Calum; Parakattil, Pius; Green, Phil; Wu, Jin Chuan

    2013-12-12

    Empty fruit bunch (EFB) of oil palm trees was converted to fermentable sugars by the combined use of dilute acids and whole fungal cell culture catalyzed hydrolyses. EFB (5%, w/v) was hydrolyzed in the presence of 0.5% H2 SO4 and 0.2% H3 PO4 at 160°C for 10 min. The solid fraction was separated from the acid hydrolysate by filtration and subjected to enzymatic hydrolysis at 50°C using the whole cell culture of Trichoderma reesei RUT-C30 (2%, w/v), which was prepared by cultivating at 30°C for 7 days to reach its maximal cellulase activity. The combined hydrolyses of EFB gave a total sugar yield of 82.0%. When used as carbon sources for cultivating E. coli in M9 medium at 37°C, the combined EFB hydrolysates were shown to be more favorable or at least as good as pure glucose for cell growth in terms of the higher (1.1 times) optical density of E. coli cells. The byproducts generated during the acid-catalyzed hydrolysis seemed not to obviously affect the cell growth. The combined use of acid and whole cell culture hydrolyses might be a commercially promising method for pretreatment of lignocellulose to get fermentable sugars. This article is protected by copyright. All rights reserved. PMID:24329860

  18. Solid olive waste in environmental cleanup: enhanced nitrite ion removal by ZnCl2-activated carbon.

    PubMed

    Zyoud, Ahed; Nassar, Hiba N I; El-Hamouz, Amer; Hilal, Hikmat S

    2015-04-01

    This communication describes how olive solid wastes can be used to prepare activated carbon (AC), with soundly high surface areas, suitable to remove nitrite ions from water. Solid olive wastes, so called Jeft, separated as unwanted bi-products from olive oil mills, have been converted into charcoal. The charcoal was then physically and/or chemically activated using different compounds namely conc. H3PO4 or ZnCl2. Charcoal carbonization was performed under inert atmosphere to avoid loss of heated carbon by oxidation with air. Surface area measurements and SEM micrographs showed that activation using ZnCl2 yields AC with highest surface area and more porous surfaces. The ZnCl2-activated carbon was then used to remove nitrite ions from water by adsorption. Effects of different parameters on value of surface area and adsorption capacity of the AC were investigated. Commercial AC materials were used as reference for comparison. The AC showed higher adsorption capacity toward nitrite than other reported adsorbents. The results suggest that using 5 g of the ZnCl2-activated carbon per liter of heavily nitrite-contaminated water (50 ppm) may bring the contaminant concentration down to the WHO accepted concentration limits within 60 min. This work highlights the future feasibility of using olive waste as feed stocks to produce useful renewable materials while keeping in mind the wisdom "make wastes work in environmental protection". PMID:25602924

  19. Nanocomposite membranes based on polybenzimidazole and ZrO2 for high-temperature proton exchange membrane fuel cells.

    PubMed

    Nawn, Graeme; Pace, Giuseppe; Lavina, Sandra; Vezzù, Keti; Negro, Enrico; Bertasi, Federico; Polizzi, Stefano; Di Noto, Vito

    2015-04-24

    Owing to the numerous benefits obtained when operating proton exchange membrane fuel cells at elevated temperature (>100?°C), the development of thermally stable proton exchange membranes that demonstrate conductivity under anhydrous conditions remains a significant goal for fuel cell technology. This paper presents composite membranes consisting of poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI4N) impregnated with a ZrO2 nanofiller of varying content (ranging from 0 to 22?wt?%). The structure-property relationships of the acid-doped and undoped composite membranes have been studied using thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, wide-angle X-ray scattering, infrared spectroscopy, and broadband electrical spectroscopy. Results indicate that the level of nanofiller has a significant effect on the membrane properties. From 0 to 8?wt?%, the acid uptake as well as the thermal and mechanical properties of the membrane increase. As the nanofiller level is increased from 8 to 22?wt?% the opposite effect is observed. At 185?°C, the ionic conductivity of [PBI4N(ZrO2 )0.231 ](H3 PO4 )13 is found to be 1.04×10(-1) ?S?cm(-1) . This renders membranes of this type promising candidates for use in high-temperature proton exchange membrane fuel cells. PMID:25801848

  20. Development of an activated carbon filter to remove NO2 and HONO in indoor air.

    PubMed

    Yoo, Jun Young; Park, Chan Jung; Kim, Ki Yeong; Son, Youn-Suk; Kang, Choong-Min; Wolfson, Jack M; Jung, In-Ha; Lee, Sung-Joo; Koutrakis, Petros

    2015-05-30

    To obtain the optimum removal efficiency of NO2 and HONO by coated activated carbon (ACs), the influencing factors, including the loading rate, metal and non-metal precursors, and mixture ratios, were investigated. The NOx removal efficiency (RE) for K, with the same loading (1.0 wt.%), was generally higher than for those loaded with Cu or Mn. The RE of NO2 was also higher when KOH was used as the K precursor, compared to other K precursors (KI, KNO3, and KMnO4). In addition, the REs by the ACs loaded with K were approximately 38-55% higher than those by uncoated ACs. Overall, the REs (above 95%) of HONO and NOx with 3% KOH were the highest of the coated AC filters that were tested. Additionally, the REs of NOx and HONO using a mixing ratio of 6 (2.5% PABA (p-aminobenzoic acid)+6% H3PO4):4 (3% KOH) were the highest of all the coatings tested (both metal and non-metal). The results of this study show that AC loaded with various coatings has the potential to effectively reduce NO2 and HONO levels in indoor air. PMID:25725340