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Sample records for kcl caoh2 h3po4

  1. 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

  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. Development of a large scale asymmetric synthesis of the glucocorticoid agonist BI 653048 BS H3PO4.

    PubMed

    Reeves, Jonathan T; Fandrick, Daniel R; Tan, Zhulin; Song, Jinhua J; Rodriguez, Sonia; Qu, Bo; Kim, Soojin; Niemeier, Oliver; Li, Zhibin; Byrne, Denis; Campbell, Scot; Chitroda, Ashish; DeCroos, Phil; Fachinger, Thomas; Fuchs, Victor; Gonnella, Nina C; Grinberg, Nelu; Haddad, Nizar; Jäger, Burkhard; Lee, Heewon; Lorenz, Jon C; Ma, Shengli; Narayanan, Bikshandarkoil A; Nummy, Larry J; Premasiri, Ajith; Roschangar, Frank; Sarvestani, Max; Shen, Sherry; Spinelli, Earl; Sun, Xiufeng; Varsolona, Richard J; Yee, Nathan; Brenner, Michael; Senanayake, Chris H

    2013-04-19

    The development of a large scale synthesis of the glucocorticoid agonist BI 653048 BS H3PO4 (1·H3PO4) is presented. A key trifluoromethyl ketone intermediate 22 containing an N-(4-methoxyphenyl)ethyl amide was prepared by an enolization/bromine-magnesium exchange/electrophile trapping reaction. A nonselective propargylation of trifluoromethyl ketone 22 gave the desired diastereomer in 32% yield and with dr = 98:2 from a 1:1 diastereomeric mixture after crystallization. Subsequently, an asymmetric propargylation was developed which provided the desired diastereomer in 4:1 diastereoselectivity and 75% yield with dr = 99:1 after crystallization. The azaindole moiety was efficiently installed by a one-pot cross coupling/indolization reaction. An efficient deprotection of the 4-methoxyphenethyl group was developed using H3PO4/anisole to produce the anisole solvate of the API in high yield and purity. The final form, a phosphoric acid cocrystal, was produced in high yield and purity and with consistent control of particle size. PMID:23544738

  4. Wet Etching of Amorphous TiO2 Thin Films Using H3PO4-H2O2 Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Okazaki, Sohei; Ohhashi, Takuya; Nakao, Shoichiro; Hirose, Yasushi; Hitosugi, Taro; Hasegawa, Tetsuya

    2013-09-01

    We report on the wet etching of amorphous undoped and Nb-doped TiO2 thin films using H3PO4-H2O2 etching solution. The etching rate (R) showed a maximum at a H3PO4 concentration of approximately 50 wt % at 80 °C, suggesting that H2PO4- and/or H3O+ is responsible for the etching reaction. The addition of H2O2 to H3PO4 solution significantly enhanced R, and an optimized solution exhibited an R of 13 nm/min at 80 °C, which is one order of magnitude higher than that using H2SO4. These results demonstrate that H3PO4-H2O2 aqueous solution is an effective etchant for TiO2-based amorphous thin films.

  5. Toluene and chlorobenzene dinitration over solid H3PO4/MoO3/SiO2 catalyst.

    PubMed

    Adamiak, Joanna; Kalinowska-Alichnewicz, Dorota; Szadkowski, Michał; Skupiński, Wincenty

    2011-11-15

    A new catalyst, H(3)PO(4)/MoO(3)/SiO(2), was prepared by modification of MoO(3)/SiO(2) using phosphoric acid. The characterization of the catalyst was performed using Infrared and Raman Spectroscopy, potentiometric titration and nitrogen adsorption-desorption methods. Molybdenum oxides were identified along with phosphomolybdic acid and polymolybdates on the modified surface. The suitability of the catalysts for toluene and chlorobenzene nitration in continuous process was examined. Toluene is effectively nitrated to dinitrotoluene (DNT) in one-stage process (96 wt.% of DNT in the product) and in mild conditions i.e. at room temperature and only with ten-fold excess of nitric acid. In chlorobenzene nitration only twelve-fold excess of nitric acid is needed to obtain as high yield as 95 wt.%. Most importantly, the novel catalysts we have developed, provide the opportunity for sulfuric acid- free nitration of aromatic compounds. PMID:21885194

  6. The influence of Sr and H3PO4 concentration on the hydration of SrCaHA bone cement.

    PubMed

    Guo, Dagang; Mao, Mengmeng; Qi, Wenli; Li, Hongyuan; Ni, Pengfei; Gao, Guohan; Xu, Kewei

    2011-12-01

    Sr-contained calcium hydroxyapatite (SrCaHA) cement is a potential biomaterial for in vivo bone repair and surgery fixation due to its excellent biodegradability, bioactivity, biocompatibility, easily shaping and self-hardening. We had ever reported the in vitro physiochemical properties, biocompatibility and in vivo degradability of the SrCaHA cement obtained by mixing a cement powder of Ca(4)(PO(4))(2)O/CaHPO(4)/SrHPO(4) and a cement liquid of diluted H(3)PO(4) aqueous solution. In the present study, we intensively studied the influences of both Sr content and H(3)PO(4) concentration in diluted phosphoric acid aqueous solution on the setting time, hydration heat-liberation behaviours, and real-time microstructure and phase evolutions of the SrCaHA cement. The results show that both PO(4)(3-) and H(+) ions in PA solution attended the hydration reaction as reactants, and thus the increase of the PA concentration not only promoted the dissolution of Ca(4)(PO(4))(2)O but also pushed the hydration progress of SrCaHA bone cement. Sr content exhibits a remarkable retardation role on the apatite transformation of the SrCaHA cement pastes which probably attributed to its higher degree of supersaturation for yielding apatite crystals and lower transformation rate when exposed to the Sr(2+)-containing hydration system. This present results contribute to a better understanding on the hydration mechanism of the new SrCaHA cement and help to the more precisely controlling of its hydration process. PMID:21979165

  7. 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.

  8. Synthesis and characterization of nanoporous anodic oxide film on aluminum in H3PO4 + KMnO4 electrolyte mixture at different anodization conditions

    NASA Astrophysics Data System (ADS)

    Verma, Naveen; Jindal, Jitender; Singh, Krishan Chander; Mari, Bernabe

    2016-04-01

    The micro structural properties of nanoporous anodic oxide film formed in H3PO4 were highly influenced by addition of a low concentration of KMnO4 (0.0005 M) in 1 M H3PO4 solution. The KMnO4 as additive enhanced the growth rate of oxide film formation as well as thickness of pore walls. Furthermore the growth rate was found increased with increase in applied current density. The increase in temperature and lack of stirring during anodization causes the thinness of pore wall which leads to increase in pore volume. With the decrease in concentration of H3PO4 in anodizing electrolyte from 1M to 0.3 M, keeping all other conditions constant, the decrease in porosity was observed. This might be due to the dissolution of aluminium oxide film in highly concentrated acidic solution.

  9. Kinetic and isotherm studies of Cu(II) adsorption onto H3PO4-activated rubber wood sawdust.

    PubMed

    Kalavathy, M Helen; Karthikeyan, T; Rajgopal, S; Miranda, Lima Rose

    2005-12-15

    Adsorption of Cu(II) from aqueous solution onto H(3)PO(4)-activated carbon using rubber wood sawdust (RSAC) was investigated in a batch system. Kinetic and isotherm studies were carried out by considering the effects of various parameters, such as initial concentration, contact time, pH, and temperature. The optimal pH value for Cu(II) adsorption onto RSAC was found to be 6.0. Thermodynamic parameters such as standard Gibbs free energy (DeltaG(0)), standard enthalpy (DeltaH(0)), and standard entropy (DeltaS(0)) were evaluated by applying the Van't Hoff equation. The thermodynamics of Cu(II) adsorption onto RSAC indicates its spontaneous and exothermic nature. Langmuir, Freundlich, and Temkin isotherms were used to analyze the equilibrium data at different temperatures. The Langmuir isotherm fits the experimental data significantly better than the other isotherms. Adsorption kinetics data were tested using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. Kinetic studies showed that the adsorption followed a pseudo-second-order reaction. The initial sorption rate, pseudo-first-order, pseudo-second-order, and intraparticle diffusion rate constants for different initial concentrations were evaluated and discussed. Adsorption mechanism studies revealed that the process was complex and followed both surface adsorption and particle diffusion. The rate-controlling parameter and effective diffusion coefficient were determined using the Reichenberg plot. It was found that the adsorption occurs through film diffusion at low concentrations and at higher concentration the particle diffusion becomes the rate-determining step. PMID:16040040

  10. 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

  11. TECHNICAL NOTE: Preparation and characterization of activated carbons made up from different woods by chemical activation with H3PO4

    NASA Astrophysics Data System (ADS)

    Macías-García, A.; Díaz-Díez, M. A.; Gómez-Serrano, V.; Fernández González, M. C.

    2003-12-01

    There are many known methods for the preparation of activated carbons. They are often classified as chemical and physical activation methods, a division widely used in the scientific literature. In this paper we study the preparation of activated carbons from different woods (chestnut, cedarwood, walnut) by chemical activation with different concentrations of phosphoric acid (36 and 85 wt%). The prepared activated carbons were characterized by the following techniques: physical adsorption of gases, mercury porosimetry, chemical analysis and measurement of density by helium and mercury displacement. The main conclusion obtained was that chemical activation with 36 wt% H3PO4 yields activated carbons with better textural properties than those prepared with 85 wt% H3PO4. The effects of activation on the textural properties of the activated carbons improve when the concentration of phosphoric acid is reduced.

  12. Preparation and textural characterisation of activated carbon from vine shoots ( Vitis vinifera) by H 3PO 4—Chemical activation

    NASA Astrophysics Data System (ADS)

    Corcho-Corral, B.; Olivares-Marín, M.; Fernández-González, C.; Gómez-Serrano, V.; Macías-García, A.

    2006-06-01

    An abundant and low-cost agricultural waste as vine shoots ( Vitis vinifera) (VS), which is generated by the annual pruning of vineyards, has been used as raw material in the preparation of powder activated carbon (AC) by the method of chemical activation with phosphoric acid. After size reduction, VS were impregnated for 2 h with 60 wt.% H 3PO 4 solution at room temperature, 50 and 85 °C. The three impregnated products were carbonised at 400 °C. The product impregnated at 50 °C was heated either first at 150-250 °C and then at 400 °C or simply at 350-550 °C in N 2 atmosphere. The time of isothermal treatment after each dynamic heating was 2 h. The carbons were texturally characterised by gas adsorption (N 2, -196 °C), mercury porosimetry, and density measurements. FT-IR spectroscopy was also applied. Better developments of surface area and microporosity are obtained when the impregnation of VS with the H 3PO 4 solution is effected at 50 °C and for the products heated isothermally at 200 and 450 °C. The mesopore volume is also usually higher for the products impregnated and heated at intermediate temperatures.

  13. Separative recovery with lime of phosphate and fluoride from an acidic effluent containing H3PO4, HF and/or H2SiF6.

    PubMed

    Gouider, Mbarka; Feki, Mongi; Sayadi, Sami

    2009-10-30

    Fluoride content and flow-rate of fertilizer plant wastewater from phosphoric acid and/or triple superphosphate (TSP) production lead to the discharge of several thousand tons of fluoride (F(-)) per year and even more for phosphate (PO4(3-)). Since sustainability is an important environmental concern, the removal methods should allow phosphorus and fluoride to be recycled as a sustainable products for use as raw materials either in agricultural or industrial applications. In the present work, separative recovery with lime of these two target species was investigated. A preliminary speciation study, carried out on the crude effluent, showed that two forms of fluoride: HF and H2SiF6 are present in a highly acidic medium (pH approximately 2). Evidence that fluoride is present under both free (HF) and combined (H2SiF6) forms, in the phosphate-containing effluent, was provided by comparing potentiometric titration curves of a crude wastewater sample and synthetic acid mixtures containing H3PO4, HF and H2SiF6. In a second step synthetic effluent containing mixtures of the following acids: HF, H2SiF6 and H3PO4, were treated with lime. The behaviour of these compounds under lime treatment was analysed. The data showed that fluoride has a beneficial effect on phosphate removal. Moreover, by acting on the precipitation pH, a "selective" recovery of fluoride and phosphate ions was possible either from phosphoric acid/hydrofluoric acid or phosphoric acid/hexafluorosilicic acid mixtures. Indeed, the first stage of the separative recovery, led to a fluoride removal efficiency of 97-98% from phosphoric acid/hydrofluoric acid mixture. It was of 93-95% from phosphoric acid/hexafluorosilicic acid mixture. During the second stage, the phosphate precipitation reached 99.8% from both acidic mixtures whereas it did not exceed 82% from a solution containing H3PO4 alone. The XRD and IR analyses showed that during lime treatment, a H2SiF6 hydrolysis occurred, instead of CaSiF6 solid formation, leading to CaF2 precipitate. Calcium fluoride and calcium phosphate based-by-products resulting from the two-step treatment process can be used as raw materials in several industrial sectors, such as ceramic and phosphate fertilizer industries. PMID:19524365

  14. Investigation of the inhibitive effect of triphenyltin 2-thiophene carboxylate on corrosion of steel in 2 M H 3PO 4 solutions

    NASA Astrophysics Data System (ADS)

    Benabdellah, M.; Aouniti, A.; Dafali, A.; Hammouti, B.; Benkaddour, M.; Yahyi, A.; Ettouhami, A.

    2006-09-01

    A new organic compound was synthesised and tested as corrosion inhibitor of steel in phosphoric acid medium using gravimetric, electrochemical polarisation and electrochemical impedance spectroscopy (EIS) measurements. Results obtained show that the inhibitor studied is a good cathodic inhibitor. EIS results show that the change in the impedance parameters ( RT and Cdl) with concentration of triphenyltin 2-thiophene carboxylate (TTC) is indicative of the adsorption of molecules leading to the formation of a protective layer on the surface of steel. The effect of the temperature on the steel corrosion in 2 M H 3PO 4 and with addition of various concentrations of TTC in the range of temperature 298-348 K was studied. The associated apparent activation corrosion energy has been determined.

  15. On the effect of the Fe(2+)/Fe(3+) redox couple on oxidation of carbon in hot H3PO4

    NASA Technical Reports Server (NTRS)

    Dhar, H. P.; Christner, L. G.; Kush, A. K.

    1986-01-01

    Oxidation studies of graphite:glassy carbon composites have been carried out at 1 and 4.7 atm. pressures in conc. H3PO4 in the presence and absence of iron ions. The concentration of the acid was varied over 85-100 wt pct, and of the iron ions over 30-300 ppm; the temperature varied over 190-210 C. Unlike the effect of Fe, which has been observed to increase the corrosion of carbon in sulphuric acid, the corrosion in phosphoric acid was observed to be slightly decreased or not at all affected. This result arises because of the catalytic reduction of the oxidized surface groups of carbon by Fe(2+) ions. The catalytic reduction is possible because under the experimental conditions the redox potential of the Fe(2+)/Fe(3+) couple is lower than the open-circuit voltage of carbon.

  16. Structure-property interplay of proton conducting membranes based on PBI5N, SiO2-Im and H3PO4 for high temperature fuel cells.

    PubMed

    Di Noto, Vito; Piga, Matteo; Giffin, Guinevere A; Quartarone, Eliana; Righetti, Pierpaolo; Mustarelli, Piercarlo; Magistris, Aldo

    2011-07-14

    Polybenzimidazoles (PBIs) are among the polymers of choice to prepare membranes for high temperature polymer fuel cells. Poly-2,2'(2,6-pyridine)-5,5'-bibenzimidazole (PBI5N), doped with H(3)PO(4), and acid-doped PBI5N containing 10 wt% of imidazole-functionalized silica membranes were studied with thermogravimetric analysis, differential scanning calorimetry, dynamic-mechanical analysis, infrared spectroscopy, and broadband electric spectroscopy to examine the structure-property relationships. Key results show that: (1) doped PBI5N membranes show thermal decomposition starting at 120 °C, while pristine PBI5N is stable up to 300 °C; (2) the presence of filler increases the acid uptake and decreases the crystallinity of PBI5N; (3) the addition of phosphoric acid reduces the mechanical properties of the membrane, while the addition of filler has the opposite effect; (4) acid-doped membranes have conductivity values on the order of 10(-2)-10(-3) S cm(-1); and (5) membranes exhibit a Vogel-Tamman-Fulcher (VTF) type proton conduction mechanism, where proton hopping is coupled with the segmental motion of the polymer chain. Infrared spectroscopy combined with DFT quantum mechanical calculations was used to assign the experimental spectrum of PBI5N. PMID:21594297

  17. 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

  18. 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

  19. Accurate approach for determining fresh-water carbonate (H2CO3(*)) alkalinity, using a single H3PO4 titration point.

    PubMed

    Birnhack, Liat; Sabach, Sara; Lahav, Ori

    2012-10-15

    A new, simple and accurate method is introduced for determining H(2)CO(3)(*) alkalinity in fresh waters dominated by the carbonate weak-acid system. The method relies on a single H(3)PO(4) dosage and two pH readings (acidic pH value target: pH~4.0). The computation algorithm is based on the concept that the overall alkalinity mass of a solution does not change upon the addition of a non-proton-accepting species. The accuracy of the new method was assessed batch-wise with both synthetic and actual tap waters and the results were compared to those obtained from two widely used alkalinity analysis methods (titration to pH~4.5 and the Gran titration method). The experimental results, which were deliberately obtained with simple laboratory equipment (glass buret, general-purpose pH electrode, magnetic stirrer) proved the method to be as accurate as the conventional methods at a wide range of alkalinity values (20-400 mg L(-1) as CaCO(3)). Analysis of the relative error attained in the proposed method as a function of the target (acidic) pH showed that at the range 4.0

  20. 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.

  1. Enhanced adsorption of chromium onto activated carbon by microwave-assisted H(3)PO(4) mixed with Fe/Al/Mn activation.

    PubMed

    Sun, Yuanyuan; Yue, Qinyan; Mao, Yanpeng; Gao, Baoyu; Gao, Yuan; Huang, Lihui

    2014-01-30

    FeCl3, AlCl3 and MnCl2 were used as the assisted activation agent in activated carbon preparation by H3PO4 activation using microwave heating method. The physico-chemical properties of activated carbons were investigated by scanning electron microscope (SEM), N2 adsorption/desorption, Boehm's titration, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). To investigate the adsorption performances of chromium onto these newly developed activated carbons, a batch of experiments were performed under different adsorption conditions: solution pH, initial Cr(VI) ion concentration, contact time and co-existing ions. The results suggested that carbon with MnCl2 as assisted activation agent displayed the highest BET surface area (1332m(2)/g) and the highest pore volume (1.060cm(3)/g). FeCl3, AlCl3 and MnCl2 had successfully improved Cr(VI) adsorption and activated carbon with FeCl3 as assisted activation agent exhibited the best uptake capacity. To study the transformation of Cr(VI) in adsorption process, total chromium in the aqueous solution was also recorded. The ratio of the amount of Cr(VI) to Cr(III) on each adsorbent was explained by XPS analysis results. Both the co-existing salts (Na2SO4 and NaNO3) demonstrated promoted effects on Cr(VI) removal by four carbons. The pseudo-second-order model and Freundlich equation displayed a good correlation with adsorption data. PMID:24361798

  2. Adsorption of Pb(II) on mesoporous activated carbons fabricated from water hyacinth using H3PO4 activation: Adsorption capacity, kinetic and isotherm studies

    NASA Astrophysics Data System (ADS)

    Huang, Yang; Li, Shunxing; Chen, Jianhua; Zhang, Xueliang; Chen, Yiping

    2014-02-01

    Activated carbons with high mesoporosity and abundant oxygen-containing functional groups were prepared from water hyacinth using H3PO4 activation (WHAC) to eliminate Pb(II) in water. Characterizations of the WHAC were performed using Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The BET analysis showed that WHAC possesses a high mesoporosity (93.9%) with a BET surface area of 423.6 m2/g. The presence of oxygen-containing functional groups including hydroxyl, carbonyl, carboxyl and phosphate groups renders the WHAC a favorable adsorbent for Pb(II) with the maximum monolayer capacity (qm) 118.8 mg/g. The adsorption behavior follows pseudo-first order kinetic and Langmuir isotherm. The desorption study demonstrated that the WHAC could be readily regenerated using 0.1 M HCl (pH = 1.0). The desorbed WHAC could be reused at least six times without significant adsorption capacity reduction. The adsorption process was spontaneous and endothermic with ΔG (-0.27, -1.13, -3.02, -3.62, -5.54, and -9.31 kJ/mol) and ΔH (38.72 kJ/mol). Under the optimized conditions, a small amount of the adsorbent (1.0 g/L) could remove as much as 90.1% of Pb(II) (50 mg/L) in 20 min at pH 6.0 and temperature of 298 K. Therefore, the WHAC has a great potential to be an economical and efficient adsorbent in the treatment of lead-contaminated water.

  3. An H3PO4-doped polybenzimidazole/Sn0.95Al0.05P2O7 composite membrane for high-temperature proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Jin, Y. C.; Nishida, M.; Kanematsu, W.; Hibino, T.

    2011-08-01

    A polybenzimidazole (PBI)/Sn0.95Al0.05P2O7 (SAPO) composite membrane was synthesized by an in situ reaction of SnO2 and Al(OH)3-mixed powders with an H3PO4 solution in a PBI membrane. The formation of a single phase of SAPO in the PBI membrane was completed at a temperature of 250 °C. Thermogravimetric analysis showed that the PBI membrane was not subject to a serious damage by the presence of SAPO until 500 °C. Scanning electron microscopy revealed that SAPO particles with a diameter of approximately 300 nm were homogeneously dispersed and separated from each other in the PBI matrix. Proton magic angle spinning nuclear magnetic resonance spectra confirmed the presence of new protons originating from the SAPO particles in the composite membrane. As a consequence of the interaction of protons in the SAPO with those in the free H3PO4, the H3PO4-doped PBI/SAPO composite membrane exhibited conductivities several times higher than those of an H3PO4-doped PBI membrane at room temperature to 300 °C, which could contribute to the improved performance of H2/O2 fuel cells.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Kılıç, Murat; Apaydın-Varol, Esin; Pütün, Ayşe 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.

  6. The Elastic Properties of Natural Portlandite Ca(OH)2

    NASA Astrophysics Data System (ADS)

    Speziale, S.; Reichmann, H. J.; Schilling, F.; Wenk, H. R.; Monteiro, P. J.

    2007-12-01

    Portlandite, Ca(OH) 2, is a simple hydroxide with brucite structure (space group P~{3}m1). It is built up of layers of CaO6 octahedra stacked along the c-axis. Portlandite is of basic interest for the cement and concrete research and industries, because it is a major primary solid phase in hydrated portland cement. It is therefore of particular importance to determine the elastic properties of portlandite. So far a computational (Laugesen, 2005) and an experimental (Holuj et al., 1985) study reported the single crystal elastic moduli Cij. However, these results differ significantly in some off-diagonal moduli. We performed Brillouin spectroscopy measurements on natural single crystal portlandite at ambient conditions. Our measurements have been performed in a new Brillouin laboratory set up at the Geoforschungszentrum, Potsdam. The new system features an Eulerian cradle with an inner diameter of 400 mm, and it has been designed to accommodate an internally heated diamond anvil cell to perform Brillouin measurements at high P and T conditions. We have obtained the following values for the elastic moduli (expressed in GPa followed by 1σ uncertainty in parentheses): C11 = 102.0 (2.0), C12 = 32.1 (1.0), C13 = 8.4 (0.4), C14 = 4.5 (0.2), C33 = 33.6 (0.7), C44 = 12.0 (0.3), C66 = (C11-C12)/2 = 35.0 (1.5). With our new measurements we put a better constraint on the value of C13 which is more than 2.5 times larger than reported by Holuj and coworkers, and is closer to the value calculated by Laugesen. A remarkable feature of the elastic behavior is the high elastic anisotropy of portlandite due to its highly anisotropic layered structure. The zero pressure Voigt and Reuss bounds to the adiabatic bulk modulus of portlandite are: K0SV = 37.3 (0.4) GPa and K0SR = 26.0 (0.3) GPa, with a 43% difference between the two bounds. The Voigt and Reuss bounds to the shear modulus are G0V = 24.4 (0.4) GPa and G0R = 17.5 (0.3) GPa, with a 40% difference between the two bounds. The large elastic anisotropy of portlandite is comparable to that of isostructural brucite Mg(OH)2.

  7. 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.

  8. 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

  9. Improvement of SO2 removal by the solubility change of Ca(OH)2 in the spray dryer system.

    PubMed

    Song, H C; Park, J W

    2001-09-01

    Experiments were carried out to verify the effect of the solubility change of the Ca(OH)2 sorbent on the removal of SO2 in a lab-scale spray dryer system. First, to identify the solubility effect, HNO3 was added into Ca(OH)2 slurry to increase the solubility of Ca(OH)2 by neutralization. The improvement of SO2 removal by 5-10% occurred under the condition of both 50% relative solubility and constant pH of slurry. But SO2 removal efficiency decreased steeply when the relative solubility approached 100% and the pH of the slurry decreased rapidly. For the practical application of the solubility effect, NH4Cl and NH4OH were selected as additives. Ammonium chloride (NH4Cl) which could improved Ca(OH)2 solubility removed more SO2 by 5-10% than NH4OH which showed no change in solubility. The optimal result was obtained when the slurry was fed at the ratio of 0.25mol NH4Cl/mol Ca(OH)2. The Ca(OH),/NH4Cl sorbent could remove more SO2 and improve Ca(OH)2 utilization than Ca(OH)2 sorbent in the Ca/S stoichiometric range of 1.0-1.4. It was concluded that the increase of sorbent solubility made the improvement in SO2 removal efficiency and Ca(OH)2 utilization. PMID:11816762

  10. Effect on Ca(OH)2 pretreatment to enhance biogas production of organic food waste

    NASA Astrophysics Data System (ADS)

    Junoh, H.; Yip, CH; Kumaran, P.

    2016-03-01

    This study investigated the effect of calcium hydroxide, Ca(OH)2 pretreatment in optimizing COD solubilisation and methane production through anaerobic digestion process. Two different parameters, chemical concentration (40-190 mEq/L) and pretreatment time (1-6 hours) were used to pretreat food waste. A central composite design and response surface methodology (RSM) was applied in obtaining the optimized condition for COD solubilisation. Result showed COD solubilisation was optimized at 166.98 mEq/L (equivalent to 6.1 g Ca(OH)2/L) for 1 hour. These conditions were applied through biomethane potential test with methane production of 864.19 mL/g VSdestructed and an increase of 20.0% as compared to untreated food waste.

  11. Extrinsic Proton NMR Studies of Mg(OH)2 and Ca(OH)2

    NASA Astrophysics Data System (ADS)

    Itoh, Yutaka; Isobe, Masahiko

    2016-03-01

    We studied narrow 1H NMR spectra of Mg(OH)2 and Ca(OH)2 powders at 100-355 K and 42-59 MHz using pulsed NMR techniques. The Fourier transformed NMR spectra of the proton free-induction signals show the superposition of broad and narrow components, which can be assigned to immobile protons and extrinsic mobile protons, respectively. We found that a narrow spectrum develops on heating above about Tc = 260 K and widens above a Larmor frequency of about νc = 50 MHz for Mg(OH)2. The temperature-induced NMR spectrum and the characteristic frequency νc of 50 MHz are the noteworthy features of the nuclear spin fluctuation spectra of the extrinsic protons.

  12. Effect of storage conditions on handling and SO2 reactivity of CA(OH)2-based sorbents

    SciTech Connect

    Jozewicz, W.; Gullett, B.K.

    1991-01-01

    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). Investigated was the effect of sorbent storage conditions of time (1-24 hr), RH (zero-90%), silo wall material, and aeration on handling properties of flowability and floodability and their subsequent effect on sorbent/SO2 reactivity. Increased RH in the storage chamber and prolonged storage increased floodability, as predicted by the angle of difference. No significant effect of RH on the flowability of Ca(OH)2, as predicted by the angle of repose, was detected. The importance of silo wall material on proper sorbent discharge pattern has been demonstrated through testing on four common surfaces. The effect of sorbent storage conditions on the reactivity of Ca(OH)2 with SO2 was evaluated in a short time differential reactor (STDR)operated under conditions typical of dry sorbent injection for SO2 control near the preheater. Increased RH and aeration with air during storage resulted in decreased reactivity of Ca(OH)2 with SO2. The effect of storage conditions on handling of novel Ca(OH)2-based sorbents for the removal of SO2 was also evaluated. ADVACATE sorbent appears to have significantly better handling properties than the other sorbents tested.

  13. 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...

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

    PubMed

    Ruiz-Agudo, Encarnación; Kudłacz, 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

  15. Novel dry-desulfurization process using Ca(OH)2/fly ash sorbent in a circulating fluidized bed.

    PubMed

    Matsushima, Norihiko; Li, Yan; Nishioka, Masateru; Sadakata, Masayoshi; Qi, Haiying; Xu, Xuchang

    2004-12-15

    A dry-desulfurization process using Ca(OH)2/fly ash sorbent and a circulating fluidized bed (CFB) was developed. Its aim was to achieve high SO2 removal efficiency without humidification and production of CaSO4 as the main byproduct. The CaSO4 produced could be used to treat alkalized soil. An 83% SO2 removal rate was demonstrated, and a byproduct with a high CaSO4 content was produced through baghouse ash. These results indicated that this process could remove SO2 in flue gas with a high efficiency under dry conditions and simultaneously produce soil amendment. It was shown that NO and NO2 enhanced the SO2 removal rate markedly and that NO2 increased the amount of CaSO4 in the final product more than NO. These results confirmed that the significant effects of NO and NO2 on the SO2 removal rate were due to chain reactions that occurred under favorable conditions. The amount of baghouse ash produced increased as the reaction progressed, indicating that discharge of unreacted Ca(OH)2 from the reactor was suppressed. Hence, unreacted Ca(OH)2 had a long residence time in the CFB, resulting in a high SO2 removal rate. It was also found that 350 degrees C is the optimum reaction temperature for dry desulfurization in the range tested (320-380 degrees C). PMID:15669351

  16. 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.

  17. 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

  18. Antifungal coatings based on Ca(OH)2 mixed with ZnO/TiO2 nanomaterials for protection of limestone monuments.

    PubMed

    Gómez-Ortíz, Nikte; De la Rosa-García, Susana; González-Gómez, William; Soria-Castro, Montserrat; Quintana, Patricia; Oskam, Gerko; Ortega-Morales, Benjamin

    2013-03-13

    The presence and deteriorating action of microbial biofilms on historic stone buildings have received considerable attention in the past few years. Among microorganisms, fungi are one of the most damaging groups. In the present work, antimicrobial surfaces were prepared using suspensions of Ca(OH)2 particles, mixed with ZnO or TiO2 nanoparticles. The antimicrobial surfaces were evaluated for their antifungal activity both in the dark and under simulated natural photoperiod cycles, using Penicillium oxalicum and Aspergillus niger as model organisms, and two limestone lithotypes commonly used in construction and as materials for the restoration of historic buildings. Both Ca(OH)2-ZnO and Ca(OH)2-TiO2 materials displayed antifungal activity: ZnO-based systems had the best antifungal properties, being effective both in the dark and under illumination. In contrast, TiO2-based coatings showed antifungal activity only under photoperiod conditions. Controls with coatings consisting of only Ca(OH)2 were readily colonized by both fungi. The antifungal activity was monitored by direct observation with microscope, X-ray diffraction (XRD), and scanning electron microscopy (SEM), and was found to be different for the two lithotypes, suggesting that the mineral grain distribution and porosity played a role in the activity. XRD was used to investigate the formation of biominerals as indicator of the fungal attack of the limestone materials, while SEM illustrated the influence of porosity of both the limestone material and the coatings on the fungal penetration into the limestone. The coated nanosystems based on Ca(OH)2-50%ZnO and pure zincite nanoparticulate films have promising performance on low porosity limestone, showing good antifungal properties against P. oxalicum and A. niger under simulated photoperiod conditions. PMID:23347459

  19. Effects of Ca(OH)(2) treatments ("overliming") on the composition and toxicity of bagasse hemicellulose hydrolysates.

    PubMed

    Martinez, A; Rodriguez, M E; York, S W; Preston, J F; Ingram, L O

    2000-09-01

    Hemicellulose syrups from dilute sulfuric acid hydrolysates of hemicellulose contain inhibitors that prevent efficient fermentation by yeast or bacteria. It is well known that the toxicity of these hydrolysate syrups can be ameliorated by optimized "overliming" with Ca(OH)(2). We have investigated the optimization of overliming treatments for sugar cane bagasse hydrolysates (primarily pentose sugars) using recombinant Escherichia coli LY01 as the biocatalyst. A comparison of composition before and after optimal overliming revealed a substantial reduction in furfural, hydroxymethylfurfural, and three unidentified high-performance liquid chromatography (HPLC) peaks. Organic acids (acetic, formic, levulinic) were not affected. Similar changes have been reported after overliming of spruce hemicellulose hydrolysates (Larsson et al., 1999). Our studies further demonstrated that the extent of furan reduction correlated with increasing fermentability. However, furan reduction was not the sole cause for reduced toxicity. After optimal overliming, bagasse hydrolysate was rapidly and efficiently fermented (>90% yield) by LY01. During these studies, titration, and conductivity were found to be in excellent agreement as methods to estimate sulfuric acid content. Titration was also found to provide an estimate of total organic acids in hydrolysate, which agreed well with the sum of acetic, levulinic, and formic acids obtained by HPLC. Titration of acids, measurement of pH before and after treatment, and furan analyses are proposed as relatively simple methods to monitor the reproducibility of hydrolysate preparations and the effectiveness of overliming treatments. PMID:10898862

  20. HISTOMICROBIOLOGIC ASPECTS OF THE ROOT CANAL SYSTEM AND PERIAPICAL LESIONS IN DOGS' TEETH AFTER ROTARY INSTRUMENTATION AND INTRACANAL DRESSING WITH Ca(OH)2 PASTES

    PubMed Central

    Soares, Janir Alves; Leonardo, Mário Roberto; da Silva, Léa Assed Bezerra; Tanomaru, Mário; Ito, Izabel Yoko

    2006-01-01

    OBJECTIVE: The purpose of this study was to evaluate the distribution of microorganisms in the root canal system (RCS) and periapical lesions of dogs' teeth after rotary instrumentation and placement of different calcium hydroxide [Ca(OHy-based intracanal dressings. MATERIALS AND METHODS: Chronic periapical lesions were experimentally induced in 80 premolar roots of four dogs. Instrumentation was undertaken using the ProFile rotary system and irrigation with 5.25% sodium hypochlorite. The following Ca(OH)2-based pastes were applied for 21 days: group 1 - Calen (n=18); group 2 - Calen+CPMC (n=20); group 3 - Ca(OH2 p.a. + anaesthetic solution (n=16) and group 4 - Ca(OH2 p.a.+ 2% chlorhexidine digluconate (n=18). Eight root canals without endodontic treatment constituted the control group. Histological sections were obtained and stained with Brown & Brenn staining technique to evaluate the presence of microorganisms in the main root canal, ramifications of the apical delta and secondary canals, apical cementoplasts, dentinal tubules, areas of cemental resorption and periapical lesions. The results were analyzed statistically by the Mann-Whitney U test (p<0.05). RESULTS: The control group showed the highest prevalence of microorganisms in all sites evaluated. Gram-positive cocci, bacilli and filaments were the most frequent morphotypes. Similar microbial distribution patterns in the RCS and areas of cementum resorption were observed in all groups (p>0.05). The percentage of RCS sites containing microorganisms in groups 1, 2, 3, 4 and control were: 67.6%, 62.5%, 78.2%, 62.0% and 87.6%, respectively. CONCLUSION: In conclusion, the histomicrobiological analysis showed that the rotary instrumentation and the different calcium hydroxide pastes employed did not effectively eliminate the infection from the RCS and periapical lesions. However, several bacteria seen in the histological sections were probably dead or were inactivated by the biomechanical preparation and calcium hydroxide-based intracanal dressing. PMID:19089058

  1. 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.

  2. Aragonite crystals grown on bones by reaction of CO2 with nanostructured Ca(OH)2 in the presence of collagen. Implications in archaeology and paleontology.

    PubMed

    Natali, Irene; Tempesti, Paolo; Carretti, Emiliano; Potenza, Mariangela; Sansoni, Stefania; Baglioni, Piero; Dei, Luigi

    2014-01-21

    The loss of mechanical properties affecting archeological or paleontological bones is often caused by demineralization processes that are similar to those driving the mechanisms leading to osteoporosis. One simple way to harden and to strengthen demineralized bone remains could be the in situ growth of CaCO3 crystals in the aragonite polymorph - metastable at atmospheric pressure -which is known to have very strong mechanical strength in comparison with the stable calcite. In the present study the controlled growth of aragonite crystals was achieved by reaction between atmospheric CO2 and calcium hydroxide nanoparticles in the presence of collagen within the deteriorated bones. In a few days the carbonation of Ca(OH)2 particles led to a mixture of calcite and aragonite, increasing the strength of the mineral network of the bone. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and Fourier transform infrared (FT-IR) spectrometry showed that aragonite crystallization was achieved. The effect of the aragonite crystal formation on the mechanical properties of the deteriorated bones was investigated by means of X-rays microtomography, helium porosimetry, atomic force microscopy (AFM), and Vickers microhardness techniques. All these data enabled to conclude that the strength of the bones increased of a factor of 50-70% with respect to the untreated bone. These results could have immediate impact for preserving archeological and paleontological bone remains. PMID:24405268

  3. Reaction characteristics of Ca(OH)2, HCl and SO2 at low temperature in a spray dryer integrated with a fabric filter.

    PubMed

    Liu, Zhen-Shu; Wey, Ming-Yen; Lin, Chiou-Liang

    2002-12-01

    The objective of this research was to evaluate the reaction characteristics of CaOH2, HCl and SO2 in the flue gas emitted by a laboratory incinerator. The amount of sulfur retained in the residues (including the spray dryer ash and baghouse ash) was also evaluated in this study. The experimental parameters included HCl concentration (500-2000 ppm), SO2 concentration (500-2000 ppm), relative humidity (40-80% RH), and the addition of CaCl2 (30 wt.%). The results indicated that an HCl concentration of 500-2000 ppm did not affect HCl removal efficiency in the spray dryer at 150 degrees C and 45+/-5% RH. On the other hand, increase in SO2 concentration from 500 to 2000 ppm enhanced SO2 removal at 150 degrees C and 75+/-5% RH. Moreover, increase in removal efficiency of SO2 was more obvious when the relative humidity was greater than 80%. When the flue gas contained both HCl and SO2 simultaneously, the removal efficiency of SO2 could increase from 56.7 to 90.33% at HCl concentration of 236 ppm. However, when the concentration of HCl exceeded 535 ppm, the removal efficiency of SO2 decreased with increasing concentration of HCl. The removal efficiency of SO2 could be increase to 97.7% with the addition of CaCl2. PMID:12423943

  4. Adsorption of 2,4-dichlorophenoxyacetic acid by mesoporous activated carbon prepared from H3PO4-activated langsat empty fruit bunch.

    PubMed

    Njoku, V O; Islam, Md Azharul; Asif, M; Hameed, B H

    2015-05-01

    The removal of toxic herbicide from wastewater is challenging due to the availability of suitable adsorbents. The Langsat empty fruit bunch is an agricultural waste and was used in this study as a cheap precursor to produce activated carbon for the adsorption of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) at different initial concentrations ranging from 50 to 400 mg/L. The produced Langsat empty fruit bunch activated carbon (LEFBAC) was mesoporous and had high surface area of 1065.65 m(2)/g with different active functional groups. The effect of shaking time, temperature and pH on 2,4-D removal were investigated using the batch technique. The adsorption capacity of 2,4-D by LEFBAC was decreased with increase in pH of solution whereas adsorption capacity increased with temperature. The adsorption data was well described by Langmuir isotherm followed by removal capacity of 261.2 mg/g at 30 °C. The results from this work showed that LEFBAC can be used as outstanding material for anionic herbicide uptake from wastewater. PMID:25721981

  5. 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

  6. Laser characteristics of KCL:O2(-)

    NASA Astrophysics Data System (ADS)

    Wilk, S. R.; Boyd, R. W.; Teegarden, K. J.

    1983-10-01

    Amplified spontaneous emission and laser action have been observed at 77 K in KCl crystals containing the superoxide ion (O2/-/). The laser operates in two bands of width approximately 50 A centered at 6350 A and 5984 A. These bands are the (lattice) phonon sidebands of vibronic transitions of the superoxide ion. At lower temperatures (approximately 6 K) amplified spontaneous emission is observed in the zero phonon line at 6294 A.

  7. 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....

  8. 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...

  9. Regulation of K-Cl cotransport: from function to genes.

    PubMed

    Adragna, N C; Di Fulvio, M; Lauf, P K

    2004-10-01

    This review intends to summarize the vast literature on K-Cl cotransport (COT) regulation from a functional and genetic viewpoint. Special attention has been given to the signaling pathways involved in the transporter's regulation found in several tissues and cell types, and more specifically, in vascular smooth muscle cells (VSMCs). The number of publications on K-Cl COT has been steadily increasing since its discovery at the beginning of the 1980s, with red blood cells (RBCs) from different species (human, sheep, dog, rabbit, guinea pig, turkey, duck, frog, rat, mouse, fish, and lamprey) being the most studied model. Other tissues/cell types under study are brain, kidney, epithelia, muscle/smooth muscle, tumor cells, heart, liver, insect cells, endothelial cells, bone, platelets, thymocytes and Leishmania donovani. One of the salient properties of K-Cl-COT is its activation by cell swelling and its participation in the recovery of cell volume, a process known as regulatory volume decrease (RVD). Activation by thiol modification with N-ethylmaleimide (NEM) has spawned investigations on the redox dependence of K-Cl COT, and is used as a positive control for the operation of the system in many tissues and cells. The most accepted model of K-Cl COT regulation proposes protein kinases and phosphatases linked in a chain of phosphorylation/dephosphorylation events. More recent studies include regulatory pathways involving the phosphatidyl inositol/protein kinase C (PKC)-mediated pathway for regulation by lithium (Li) in low-K sheep red blood cells (LK SRBCs), and the nitric oxide (NO)/cGMP/protein kinase G (PKG) pathway as well as the platelet-derived growth factor (PDGF)-mediated mechanism in VSMCs. Studies on VSM transfected cells containing the PKG catalytic domain demonstrated the participation of this enzyme in K-Cl COT regulation. Commonly used vasodilators activate K-Cl COT in a dose-dependent manner through the NO/cGMP/PKG pathway. Interaction between the cotransporter and the cytoskeleton appears to depend on the cellular origin and experimental conditions. Pathophysiologically, K-Cl COT is altered in sickle cell anemia and neuropathies, and it has also been proposed to play a role in blood pressure control. Four closely related human genes code for KCCs (KCC1-4). Although considerable information is accumulating on tissue distribution, function and pathologies associated with the different isoforms, little is known about the genetic regulation of the KCC genes in terms of transcriptional and post-transcriptional regulation. A few reports indicate that the NO/cGMP/PKG signaling pathway regulates KCC1 and KCC3 mRNA expression in VSMCs at the post-transcriptional level. However, the detailed mechanisms of post-transcriptional regulation of KCC genes and of regulation of KCC2 and KCC4 mRNA expression are unknown. The K-Cl COT field is expected to expand further over the next decades, as new isoforms and/or regulatory pathways are discovered and its implication in health and disease is revealed. PMID:15711773

  10. 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.

  11. Protein-induced morphological transitions in KCl crystal growth.

    PubMed

    Szab, Blint; Vicsek, Tams

    2003-01-01

    We investigated the formation of KCl crystals on a glass surface by phase contrast, fluorescent, and atomic force microscopy on the micrometer scale and observed interesting morphological transitions as a function of the experimental conditions. The presence of proteins in the solution from which the salt crystals grow during the drying up leads to complex microscopic patterns of crystals, some of which are analogous to those commonly observed on the macroscopic scale. We tested the effect of tubulin, FITC-labeled albumin, and IgG on the morphology of crystals grown either slowly or fast. A rich variety of protein-specific and concentration-dependent morphologies was found and described by a morphological diagram. We give a phenomenological interpretation, which can explain the growth of complex patterns. Fluorescent images prove that a protein layer covers the surface of the KCl structures. We propose that this layer reduces the anisotropy of the effective surface tension during growth. The tip splitting fractal regime is attributed to the decrease of anisotropy. Further possible mechanisms, which can cause a morphological transition, are also discussed. We found elongated saw-toothed crystals induced by proteins, especially IgG, and identified their structure. PMID:12636533

  12. 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.

  13. 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.

  14. 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.

  15. An XPS study of the KCl surface oxidation in oxygen glow discharge

    NASA Astrophysics Data System (ADS)

    Stoch, J.; Ladecka, M.

    1988-05-01

    The reaction between the surface of KCl and oxygen in a glow discharge has been studied by X-ray photoemission spectroscopy (XPS). Oxygen glow discharge treatment resulted in the formation of a superoxide, which decomposed under vacuum at room temperature to KO 2 and finally to K 2O. No evidence of KClO 3 or KClO 4 formation has been found. Binding energies of some oxygen species in potassium oxides were determined. The possible role of potassium in K-doped silver catalysts of ethylene epoxidation is discussed.

  16. 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.

  17. 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

  18. 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.

  19. 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 ...

  20. 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.

  1. 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

  2. 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 (ρH2O) 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=γH2O[xH2O+(1+(1+α)xKCl)], and aKCL=γKCl[(1+α)xKCl/(xH2O+(1+α)xKCl)](1+α), where α is a degree of dissociation parameter which increases from zero at the lowest pressures to near one at high pressures and the γ's are activity coefficients based on an empirical regular solution parameter W: ln γi=(1-xi)2W. Least squares fitting of our H2O and KCl activity data evaluates the parameters: α=exp(4.166 -2.709/ρH2O) - 212.1P/T, and W=(-589.6-23.10P) /T, with ρH2O 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.

  3. Thermoluminescence behavior of KClXBr1-X: In mixed crystals exposed to gamma radiation

    NASA Astrophysics Data System (ADS)

    Rezaee Ebrahim Saraee, Kh.; Hosseini, S. A.; Faripour, H.; Faiez, M. R.; Abdi, M. R.; Soltani, N.; Aghay Khareiky, A.

    2014-09-01

    In-doped KClXBr1-X (X=1, 0.75, 0.5, 0.25 and 0) mixed crystal has been grown by the Czochralski method. The segregation coefficient of In was studied by the inductively coupled plasma atomic emission spectrometry (ICP-OES). The crystal structure has been determined using X-ray diffraction (XRD) analysis. The thermoluminescence (TL) characterization of KClXBr1-X mixed crystals, exposed to gamma radiation has been performed. The results show the introduction of the dopants ions induced changes in the TL glow curve structure. The TL results suggest that doped KClXBr1-X mixed crystal has good potential active dosimeter applications for gamma ray irradiation.

  4. Theoretical investigations on KCl xBr 1-x, KCl xI 1-x and KBr xI 1-x: A first-principles study

    NASA Astrophysics Data System (ADS)

    Amrani, B.; Kazempoor, A.; Khosravizadeh, Sh.; El Haj Hassan, F.; Akbarzadeh, H.

    2008-08-01

    Using first-principles total energy calculations within the full-potential linearized augmented plane wave (FP-LAPW) method, we have investigated the structural, electronic and thermodynamic properties of potassium halides (KCl xBr 1-x, KCl xI 1-x and KBr xI 1-x), with x concentrations varying from 0% up to 100%. The effect of composition on lattice constants, bulk modulus, band gap and dielectric function was investigated. Deviations of the lattice constants from Vegard's law and the bulk modulus from linear concentration dependence (LCD) were observed for the three alloys. The microscopic origins of the gap bowing were explained by using the approach of Zunger and coworkers. On the other hand, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing Δ Hm as well as the phase diagram.

  5. 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.

  6. Theoretical and empirical investigations of KCl:Eu{sup 2+} for nearly water-equivalent radiotherapy dosimetry

    SciTech Connect

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

    2010-01-15

    Purpose: The low effective atomic number, reusability, and other computed radiography-related advantages make europium doped potassium chloride (KCl:Eu{sup 2+}) a promising dosimetry material. The purpose of this study is to model KCl:Eu{sup 2+} point dosimeters with a Monte Carlo (MC) method and, using this model, to investigate the dose responses of two-dimensional (2D) KCl:Eu{sup 2+} storage phosphor films (SPFs). Methods: KCl:Eu{sup 2+} point dosimeters were irradiated using a 6 MV beam at four depths (5-20 cm) for each of five square field sizes (5x5-25x25 cm{sup 2}). The dose measured by KCl:Eu{sup 2+} was compared to that measured by an ionization chamber to obtain the magnitude of energy dependent dose measurement artifact. The measurements were simulated using DOSXYZnrc with phase space files generated by BEAMnrcMP. Simulations were also performed for KCl:Eu{sup 2+} films with thicknesses ranging from 1 {mu}m to 1 mm. The work function of the prototype KCl:Eu{sup 2+} material was determined by comparing the sensitivity of a 150 {mu}m thick KCl:Eu{sup 2+} film to a commercial BaFBr{sub 0.85}I{sub 0.15}:Eu{sup 2+}-based SPF with a known work function. The work function was then used to estimate the sensitivity of a 1 {mu}m thick KCl:Eu{sup 2+} film. Results: The simulated dose responses of prototype KCl:Eu{sup 2+} point dosimeters agree well with measurement data acquired by irradiating the dosimeters in the 6 MV beam with varying field size and depth. Furthermore, simulations with films demonstrate that an ultrathin KCl:Eu{sup 2+} film with thickness of the order of 1 {mu}m would have nearly water-equivalent dose response. The simulation results can be understood using classic cavity theories. Finally, preliminary experiments and theoretical calculations show that ultrathin KCl:Eu{sup 2+} film could provide excellent signal in a 1 cGy dose-to-water irradiation. Conclusions: In conclusion, the authors demonstrate that KCl:Eu{sup 2+}-based dosimeters can be accurately modeled by a MC method and that 2D KCl:Eu{sup 2+} films of the order of 1 {mu}m thick would have minimal energy dependence. The data support the future research and development of a KCl:Eu{sup 2+} storage phosphor-based system for quantitative, high-resolution multidimensional radiation therapy dosimetry.

  7. Study of the phototransferred thermoluminescence in KCl:Eu2+ phosphors.

    PubMed

    Pedroza-Montero, M; Meléndrez, R; Chernov, V; Barboza-Flores, M; Castañeda, B

    2002-01-01

    The phototransferred thermoluminescence (PITL) processes play an important role in the optical stimulated luminescence (OSL) and thermoluminescence (TL) dosimetric properties in KCl:Eu2+ crystals. In the present work, experimental evidence is presented about the participation of F and Fz centres in the associated recombination luminescence mechanisms involved with all three phenomena. An analysis of the TL glow curve of KCl:Eu2+ exposed to X ray ionising radiation shows three main thermoluminescence peaks around 370, 390 and 470 K. The 470 K highest intensity peak, considered the dosimetric peak due to its low fading and linear dose behaviour, is strongly correlated to the F and Fz centres. Through optical absorption spectra measurements of an optically bleached specimen, it was found that a minimum occurs at 560 nm, coinciding with the F centre band in KCl:Eu2+. Moreover, the diminishing of the integrated TL 470 K peak intensity is also seen to have a minimum at 560 nm (F centres); it also happens simultaneously with an increase of the integrated TL peak associated to the Fz band. This supports the close relation of the F and Fz centres in the PTTL process in KCl:Eu2+. PMID:12382857

  8. Life at high salt concentrations, intracellular KCl concentrations, and acidic proteomes

    PubMed Central

    Oren, Aharon

    2013-01-01

    Extremely halophilic microorganisms that accumulate KCl for osmotic balance (the Halobacteriaceae, Salinibacter) have a large excess of acidic amino acids in their proteins. This minireview explores the occurrence of acidic proteomes in halophiles of different physiology and phylogenetic affiliation. For fermentative bacteria of the order Halanaerobiales, known to accumulate KCl, an acidic proteome was predicted. However, this is not confirmed by genome analysis. The reported excess of acidic amino acids is due to a high content of Gln and Asn, which yield Glu and Asp upon acid hydrolysis. The closely related Halorhodospira halophila and Halorhodospira halochloris use different strategies to cope with high salt. The first has an acidic proteome and accumulates high KCl concentrations at high salt concentrations; the second does not accumulate KCl and lacks an acidic proteome. Acidic proteomes can be predicted from the genomes of some moderately halophilic aerobes that accumulate organic osmotic solutes (Halomonas elongata, Chromohalobacter salexigens) and some marine bacteria. Based on the information on cultured species it is possible to understand the pI profiles predicted from metagenomic data from hypersaline environments. PMID:24204364

  9. 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.

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

    PubMed

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

    2009-08-01

    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

  11. 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

  12. Performance of KCl:Eu2+ storage phosphor dosimeters for low dose measurements

    PubMed Central

    Li, H. Harold; Hansel, Rachael; Knutson, Nels; Yang, Deshan

    2013-01-01

    Recent research has demonstrated that europium doped potassium chloride (KCl:Eu2+) storage phosphor material has the potential to become the physical foundation of a novel and reusable dosimetry system using either film-like devices or devices similar to thermoluminescent dosimeter (TLD) chips. The purposes of this work are to quantify the performance of KCl:Eu2+ prototype dosimeters for low dose measurements and to demonstrate how it can be incorporated into clinical application for in vivo peripheral dose measurements. Pellet-style KCl:Eu2+ dosimeters, 6 mm in diameter, and 1 mm thick, were fabricated in-house for this study. The dosimeters were read using a laboratory photostimulated luminescence detection system. KCl:Eu2+ prototype storage phosphor dosimeter was capable of measuring a dose-to-water as low as 0.01 cGy from a 6 MV photon beam with a signal-to-noise ratio greater than 6. A pre-readout thermal annealing procedure enabled the dosimeter to be read within an hour post irradiation. After receiving large accumulated doses (~10 kGy), the dosimeters retained linear response in the low dose region with only a 20 percent loss of sensitivity comparing to a fresh sample (zero Gy history). The energy-dependence encountered during low dose peripheral measurements could be accounted for via a single point outside-field calibration per each beam quality. With further development the KCl:Eu2+? based dosimeter could become a versatile and durable dosimetry tool with large dynamic range (sub-cGy to 100 Gy). PMID:23735856

  13. Functional and molecular characterization of the K-Cl cotransporter of Xenopus laevis oocytes.

    PubMed

    Mercado, A; de los Heros, P; Vázquez, N; Meade, P; Mount, D B; Gamba, G

    2001-08-01

    The K-Cl cotransporters (KCCs) have a broad range of physiological roles, in a number of cells and species. We report here that Xenopus laevis oocytes express a K-Cl cotransporter with significant functional and molecular similarity to mammalian KCCs. Under isotonic conditions, defolliculated oocytes exhibit a Cl(-)-dependent (86)Rb(+) uptake mechanism after activation by the cysteine-reactive compounds N-ethylmaleimide (NEM) and mercuric chloride (HgCl(2)). The activation of this K-Cl cotransporter by cell swelling is prevented by inhibition of protein phosphatase-1 with calyculin A; NEM activation of the transporter was not blocked by phosphatase inhibition. Kinetic characterization reveals apparent values for the Michaelis-Menten constant of 27.7 +/- 3.0 and 15.4 +/- 4.7 mM for Rb(+) and Cl(-), respectively, with an anion selectivity for K(+) transport of Cl(-) = PO(4)(3-) = Br(-) > I(-) > SCN(-) > gluconate. The oocyte K-Cl cotransporter was sensitive to several inhibitors, including loop diuretics, with apparent half-maximal inhibition values of 200 and 500 microM for furosemide and bumetanide, respectively. A partial cDNA encoding the Xenopus K-Cl cotransporter was cloned from oocyte RNA; the corresponding transcript is widely expressed in Xenopus tissues. The predicted COOH-terminal protein fragment exhibited particular homology to the KCC1/KCC3 subgroup of the mammalian KCCs, and the functional characteristics are the most similar to those of KCC1 (Mercado A, Song L, Vazquez N, Mount DB, and Gamba G. J Biol Chem 275: 30326--30334, 2000). PMID:11443066

  14. 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 the melts where the "phlogopite" component is predominant. Thus, the preliminary experimental data show that KCl decreases the solidus temperature of the hydrous peridotite. This result contradicts with the experiments on melting of the Mg2SiO4+MgSiO3 system in presence of H2O+KCl at 5 GPa (Chu et al., 2011) showing the increase of melting temperature with an increase of KCl content in the system. The present experimental results indicate an important role of alumina as a component regulating phase relations in H2O-bearing peridotite in presence of alkali chlorides. The study is supported by Russian Foundation for Basic Research (project #10-05-00040) and RF President Grant for young scientists (project #MD-222.2012.5).

  15. Excitons in Mg(OH)2 and Ca(OH)2 from ab initio calculations

    NASA Astrophysics Data System (ADS)

    Pishtshev, A.; Karazhanov, S. Zh.; Klopov, M.

    2014-09-01

    By using ab initio calculations with the HSE06 hybrid functional and GW approximation combined with numerical solution of the Bethe Salpeter equation (GW-BSE) we predict the existence of diverse number of excitonic states in multifunctional hydroxides X(OH)2 (X=Mg and Ca) that were not previously reported experimentally or theoretically. The imaginary part of the dielectric function and the reflectivity spectra show very strong peaks corresponding to the electron-hole pair states of large binding energy. The origin of the excitons is attributed to strong localization of the hole and the electron associated with oxygen 2px,2py occupied states as well as to oxygen and earth metal s empty states, respectively. The results have important implications for different applications of the materials in optoelectronic devices.

  16. Volume properties of melts of the KF-KCl-HfF/sub 4/ system

    SciTech Connect

    Darienko, S.E.; Katyshev, S.F.; Chervinskii, Yu.F.

    1988-01-10

    Starting salts of purity grade cp were prepared; the hafnium fluoride was purified by double vacuum distillation. Experimental data were reduced using the method of least squares; results are presented for the measurements of the density of the fused mixtures of the KF-KCl-HfF/sub 4/. The highest concentration of hafnium fluoride in the mixtures was limited to 50 mole % due to the increase in the compressibility of its vapor. The density of the fused KF-KCl-HfF/sub 4/ salt mixtures increased with increased hafnium fluoride content. The concentrational dependence of the excess molar volumes is complex and indicates that on mixing the three components in the fused state, the interaction among the components is more complicated than for gas-phase interactions.

  17. High-temperature deformation behavior of KCl-RbCl solid solution alloys

    SciTech Connect

    Duong, H.; McClelland, R.J.; Wolfenstine, J. ); Beeman, M. )

    1992-05-01

    It is well established that the creep behavior of metallic solid solution alloys can be divided into two types. The main criterion for this classification is based on the value of the stress exponent, n. When n {approximately} 5 the creep behavior of the metallic solid solution alloys is similar to that observed in pure metals, where the rate-controlling deformation mechanism is attributed to a dislocation climb process. This type of metallic alloy is designated as a class II solid solution ally after the original classification of Sherby and Burke and Cannon and Sherby. It is the purpose of this paper to present some preliminary results on the creep behavior of KCl-RbCl solid solution alloys and to compare these results with that observed in the KCl-NaCl system and metallic solid solution alloys. The variation of the stress exponent and dislocation substructure with composition will be reported.

  18. 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.

  19. 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.

  20. Functional comparison of the K+-Cl- cotransporters KCC1 and KCC4.

    PubMed

    Mercado, A; Song, L; Vazquez, N; Mount, D B; Gamba, G

    2000-09-29

    The K(+)-Cl(-) cotransporters (KCCs) are members of the cation-chloride cotransporter gene family and fall into two phylogenetic subgroups: KCC2 paired with KCC4 and KCC1 paired with KCC3. We report a functional comparison in Xenopus oocytes of KCC1 and KCC4, widely expressed representatives of these two subgroups. KCC1 and KCC4 exhibit differential sensitivity to transport inhibitors, such that KCC4 is much less sensitive to bumetanide and furosemide. The efficacy of these anion inhibitors is critically dependent on the concentration of extracellular K(+), with much higher inhibition in 50 mm K(+) versus 2 mm K(+). KCC4 is also uniquely sensitive to 10 mm barium and to 2 mm trichlormethiazide. Kinetic characterization reveals divergent affinities for K(+) (K(m) values of approximately 25.5 and 17.5 mm for KCC1 and KCC4, respectively), probably due to variation within the second transmembrane segment. Although the two isoforms have equivalent affinities for Cl(-), they differ in the anion selectivity of K(+) transport (Cl(-) > SCN(-) = Br(-) > PO(4)(-3) > I(-) for KCC1 and Cl(-) > Br(-) > PO(4)(-3) = I(-) > SCN(-) for KCC4). Both KCCs express minimal K(+)-Cl(-) cotransport under isotonic conditions, with significant activation by cell swelling under hypotonic conditions. The cysteine-alkylating agent N-ethylmaleimide activates K(+)-Cl(-) cotransport in isotonic conditions but abrogates hypotonic activation, an unexpected dissociation of N-ethylmaleimide sensitivity and volume sensitivity. Although KCC4 is consistently more volume-sensitive, the hypotonic activation of both isoforms is critically dependent on protein phosphatase 1. Overall, the functional comparison of these cloned K(+)-Cl(-) cotransporters reveals important functional, pharmacological, and kinetic differences with both physiological and mechanistic implications. PMID:10913127

  1. 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.

  2. Electrode potentials of uranium in the LiCl-KCl-CsCl eutectic melt

    NASA Astrophysics Data System (ADS)

    Maltsev, D. S.; Volkovich, V. A.; Vladykin, E. N.; Vasin, B. D.

    2015-08-01

    The electrode potentials of uranium in the melt of the eutectic mixture of lithium, potassium, and cesium chlorides are measured in the temperature range 573-1073 K. Formal standard potentials E U * (III)/U and the main thermodynamic characteristics of uranium trichloride in the LiCl-KCl-CsCl melt are calculated, and the electronic absorption spectra of UCl 6 3- ions are measured.

  3. Generation of KCL039 clinical grade human embryonic stem cell line

    PubMed Central

    Devito, Liani; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL039 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  4. Generation of KCL037 clinical grade human embryonic stem cell line

    PubMed Central

    Miere, Cristian; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL037 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  5. Generation of KCL038 clinical grade human embryonic stem cell line

    PubMed Central

    Miere, Cristian; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL038 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  6. Generation of KCL032 clinical grade human embryonic stem cell line

    PubMed Central

    Miere, Cristian; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL032 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  7. Generation of KCL040 clinical grade human embryonic stem cell line

    PubMed Central

    Jacquet, Laureen; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL040 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  8. Generation of KCL031 clinical grade human embryonic stem cell line

    PubMed Central

    Jacquet, Laureen; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Hobbs, Carl; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL031 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro and in vivo assays.

  9. (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

  10. X-ray storage performance of KCl:Eu2+ with high cumulated dose

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    The effects of high cumulative radiation dose on the luminescence properties of KCl:Eu2+ are investigated. Pellet samples of KCl:Eu2+ were given doses of up to 200 kGy at the Louisiana State University Synchrotron facility. After synchrotron irradiation, samples were optically bleached and given a clinical dose of 2 Gy from a 6 MV medical linear accelerator. Optical properties were evaluated using photostimulated luminescence (PSL), photoluminescence (PL), and temperature-dependent PSL measurements. For a cumulated dose of up to 5-10 kGy, the PSL emission intensity increased by 15% compared to the PSL signal with no radiation history. For doses higher than 10 kGy, the PSL emission intensity retained at least 70% of the original intensity. Spatial correlation of the charge storage centers increased for doses up to 5 kGy and then decreased for higher cumulative doses. Emission band at 975 nm was attributed to transitions of Eu1+. PL spectra showed an intense peak centered at 420 nm for all cumulative doses. The results of this work show that KCl:Eu2+ storage phosphors are excellent reusable materials for radiation therapy dosimetry.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Electroreduction of yttrium ions in an equimolar NaCl–KCl molten mixture

    NASA Astrophysics Data System (ADS)

    Tolstobrov, I. V.; El'kin, O. V.; Kovalevskii, A. V.; Chebykin, V. V.

    2015-08-01

    The behavior of yttrium ions in an equimolar NaCl-KCl melt is studied in a temperature range of 973-1123 K using cyclic voltammetry at an inert electrode containing 5 wt % YCl3 in the range of potential sweep rates from 0.02 to 0.2 V/s. A cathodic reaction proceeds via the scheme Y(III) + 3 e = Y. The diffusion coefficients of yttrium ions are determined, and the activation energy of the diffusion of yttrium ions is estimated.

  20. Generation of KCL034 clinical grade human embryonic stem cell line

    PubMed Central

    Devito, Liani; Jacquet, Laureen; Petrova, Anastasia; Miere, Cristian; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL034 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro assays. The line was also validated for sterility, specific and non-specific human pathogens.

  1. Generation of KCL033 clinical grade human embryonic stem cell line

    PubMed Central

    Devito, Liani; Petrova, Anastasia; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL033 human embryonic stem cell line was derived from a normal healthy blastocyst donated for research. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment and under current Good Manufacturing Practice (cGMP) standards. Pluripotent state and differentiation potential were confirmed by in vitro assays. The line was also validated for sterility and specific and non-specific human pathogens.

  2. An electrochemical study of uranium behaviour in LiCl-KCl-CsCl eutectic melt

    NASA Astrophysics Data System (ADS)

    Maltsev, D. S.; Volkovich, V. A.; Vasin, B. D.; Vladykin, E. N.

    2015-12-01

    Electrochemical behaviour of uranium was studied in the low melting ternary LiCl-KCl-CsCl eutectic at 573-1073 K employing potentiometry, cyclic voltammetry and chronopotentiometry. Uranium electrode potentials were measured directly and U(III)/U(IV) red-ox potentials were determined from the results of cyclic voltammetry measurements. Formal standard electrode and red-ox potentials of uranium, and thermodynamic properties of uranium chlorides in the studied melt were calculated. Diffusion coefficients of U(III) and U(IV) ions were determined using cyclic voltammetry and chronopotentiometry.

  3. Mechanisms of low Na+-induced increase in intracellular calcium in KCl-depolarized rat cardiomyocytes.

    PubMed

    Rathi, Satyajeet S; Saini, Harjot K; Xu, Yan-Jun; Dhalla, Naranjan S

    2004-08-01

    Although low Na+ is known to increase the intracellular Ca2+ concentration ([Ca2+]i) in cardiac muscle, the exact mechanisms of low Na+ -induced increases in [Ca2+]i are not completely defined. To gain information in this regard, we examined the effects of low Na+ (35 mM) on freshly isolated cardiomyocytes from rat heart in the absence and presence of different interventions. The [Ca2+]i in cardiomyocytes was measured fluorometrically with Fura-2 AM. Following a 10 min incubation, the low Na+ -induced increase in [Ca2+], was only observed in cardiomyocytes depolarized with 30 mM KCl, but not in quiescent cardiomyocytes. In contrast, low Na+ did not alter the ATP-induced increase in [Ca2+]i in the cardiomyocytes. This increase in [Ca2+]i due to low Na+ and elevated KCl was dependent on the extracellular concentration of Ca2+ (0.25-2.0 mM). The L-type Ca2+ -channel blockers, verapamil and diltiazem, at low concentrations (1 microM) depressed the low Na+, KCl-induced increase in [Ca2+]i without significantly affecting the response to low Na+ alone. The low Na+, high KCl-induced increase in [Ca2+]i was attenuated by treatments of cardiomyocytes with high concentrations of both verapamil (5 and 10 microM), and diltiazem (5 and 10 microM) as well as with amiloride (5-20 microM), nickel (1.25-5.0 mM), cyclopiazonic acid (25 and 50 microM) and thapsigargin (10 and 20 microM). On the other hand, this response was augmented by ouabain (1 and 2 mM) and unaltered by 5-(N-methyl-N-isobutyl) amiloride (5 and 10 microM). These data suggest that in addition to the sarcolemmal Na+ - Ca2+ exchanger, both sarcolemmal Na+ - K+ ATPase, as well as the sarcoplasmic reticulum Ca2+ -pump play prominent roles in the low Na+ -induced increase in [Ca2+]i. PMID:15524176

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Thermodynamics of neptunium in LiCl-KCl eutectic/liquid bismuth systems

    SciTech Connect

    Sakamura, Y.; Shirai, O.; Iwai, T.; Suzuki, Y.

    2000-02-01

    Thermodynamic properties of neptunium in LiCl-KCl eutectic/liquid bismuth systems in the temperature range 400--500 C have been studied using a galvanic cell method for the pyrometallurgical reprocessing of nuclear spent fuels. The standard potential of the Np/Np(III) couple vs. the Ag/AgCl (1 wt% AgCl) reference electrode in LiCl-KCl eutectic was measured and given by the equation E{sub Np/Np(III)}{sup 0} = {minus}2.0667 + 0.0007892 T ({sigma} = 0.0009), where E is in volts, T is in kelvin, and {sigma} is the standard deviation. The potential of neptunium-bismuth alloy, E{sub Np-Bi}, was measured as a function of neptunium concentration, X{sub Np in Bi}. The curves for E{sub Bi-Np} vs. log X{sub Np in Bi} indicated the neptunium solubility in liquid bismuth to be 0.34 {+-} 0.02, 0.61 {+-} 0.08, and 1.06 {+-} 0.09 ({+-}{sigma}) atom % at 400, 450, and 500 C, respectively. The excess partial free energy of neptunium in liquid bismuth was represented by the equation, {Delta}{bar G}{sub Np}{sup xs} (kcal/g atom) = {minus}32.5 ({+-}0.7) + 0.0072 ({+-}0.0010) T. The values of the solubility and excess partial free energy for neptunium were closer to those for plutonium rather than uranium.

  9. Generation of (F+2)_AH Centres in Sodium Ion Doped KCl:CO^{2-3}

    NASA Astrophysics Data System (ADS)

    Diaf, M.; Chihi, I.; Hamaïdia, A.; Akrmi, El.

    1996-01-01

    We demonstrate that (F+2)AH centres of KCl may be obtained from crystals doped with K{2}CO{3} and NaCl, grown by the Czochralski method in open atmosphere. The optical properties of (F+2)AH centres thus produced are exactly the same as those of (F+2)AH centres prepared by the usual technique, which involves superoxide doping and a controlled atmosphere. Nous montrons que les centres (F+2)AH de KCl peuvent être obtenus à partir de cristaux dopés par K{2}CO{3} et NaCl, fabriqués par la méthode de Czochralski à l'air libre. Les propriétés optiques des centres (F+2)AH ainsi produits sont exactement les mêmes que celles des centres (F+2)AH préparés par la technique habituelle, qui comporte le dopage par un superoxyde et l'emploi d'une atmosphère contrôlée.

  10. Protein tyrosine phosphorylation and the regulation of KCl cotransport in trout erythrocytes.

    PubMed

    Weaver, Y R; Cossins, A R

    1996-08-01

    Electroneutral salt transporters are activated and deactivated by changes to the phosphorylation status either of the transporter itself or of other, as yet unidentified, regulatory proteins. We have studied the effects of an inhibitor of protein tyrosine kinase (PTK), genistein, upon KCl cotransport in trout erythrocytes. We show that Cl-dependent K fluxes activated by physiological stimuli, i.e. oxygenation and beta-adrenergic agonists, are rapidly and completely blocked by genistein, whilst the inactive analogue of genistein, daidzein, had no effect. By contrast, the protein tyrosine phosphatase (PTP) inhibitor, vanadate (V), caused a slow but strong activation of an inactive cotransporter. This vanadate (V) activated flux was inhibited by genistein as well as by the serine/threonine phosphatase (PSP) inhibitor, calyculin A. However, genistein had no effect upon the activation of the cotransporter by the protein (serine/threonine) kinase (PSK) inhibitor, staurosporine, or by N-ethylmaleimide, which also appears to act by inhibiting a PSK. These results are consistent with a sequential scheme of at least two tyrosine phosphorylation events which lie upstream to the serine/threonine phosphorylation sites in the signal transduction pathway leading from stimulus to transporter activation. The regulation of the activity of KCl cotransporter appears to involve a complex series of phosphorylation reactions. PMID:8764975

  11. 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.

  12. A morphometric analysis of exocytosis in KCl-stimulated bovine chromaffin cells.

    PubMed

    Fox, G Q

    1996-05-01

    Transmission electron microscopy has been used to morphometrically evaluate exocytosis in bovine adrenal medulla chromaffin cells as the mechanism of catecholamine release. Purified cell suspensions were stimulated with KCl at varying strengths and durations and then conventionally processed for ultrastructural analysis. Quantitation of exocytotic images of dense cored chromaffin granules was a major objective and such images were found in all preparations, attesting to the efficacy of chemical fixation to preserve this event. However, because hundreds of cell profiles had to be screened to find a single granule in the process of release this low frequency precluded any meaningful correlations with estimates of granular involvement based on catecholamine release. Neither KCl molarity nor duration altered this finding nor did these variables significantly affect other parameters linked to exocytotic activity. For example, cell size and numbers of "empty' granules and vesicles remained constant and attempts to label "any' organelle with 30-nm colloidal gold or lanthanum precipitate proved unsuccessful. In short, if exocytosis is responsible for release, it would appear to function without leaving a morphological trace. An alternative hypothesis, therefore, is outlined which better accommodates existing data. PMID:8625396

  13. 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.

  14. 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.

  15. Computer simulation of electron states of the isoelectronic substitutional impurities in quantum wire of KCl with edge dislocation

    NASA Astrophysics Data System (ADS)

    Timoshenko, Yury K.; Shunina, Valentina A.; Shashkin, Alexander I.

    2015-01-01

    The electron states of quantum wires KCl, KCl : Br, and KCl : I with an edge dislocations were investigated. The main problem was in study of dislocation influence on localized electron states connected with substitutional isoelectronic impurities Br- and I- in the neighborhood of edge dislocation line. The tight-binding semi-empirical band approximation, semi-empirical and non-empirical cluster approach were used. Semi-empirical calculations were carried out in framework of model [1,2]. Besides, the algorithms for electronic levels calculations of polar nanosystems with the partial self-consistency [3] were used. The computer simulation results lead to the conclusion that the substitutional isoelectronic impurity anions Br- and I- located near the dislocation line capture the holes more efficiently than in bulk of systems without dislocations.

  16. Effect of Aluminum Particle Surface Area and Morphology on the Combustion Properties of KClO4/Al Compositions

    NASA Astrophysics Data System (ADS)

    Caulder, Stanley; Mackey, Joseph; Wilkinson, John

    2009-06-01

    Compositions of KClO4/Al are used in military applications as well as the pyrotechnics industry. The reaction rate as well as the ease of initiation depends on metal particle surface area as well as particle morphology. This factor is especially important for metal fuels having a melting point higher than the melting point of the oxidizer component in the energetic composition. Aluminum powder and turnings of various particle sizes were combined with KClO4 to form an energetic composition. The explosives mixtures were combusted in a rapid scanning calorimeter device (RSD). dP/dt and dT/dt results were measured and heats of reaction were calculated. The effect of Al particle surface area and particle morphology on the combustion properties of KClO4/Al is discussed.

  17. Neural representation of the taste of NaCl and KCl in gustatory neurons of the hamster solitary nucleus.

    PubMed

    Boughter, J D; St John, S J; Smith, D V

    1999-06-01

    NaCl and KCl are monovalent salts that can be discriminated behaviorally by hamsters on the basis of their tastes. We examined the effects of the passive Na+ channel blocker amiloride on responses to both of these salts in 34 taste-responsive neurons of the nucleus of the solitary tract (NST) in the hamster. The effects of amiloride were assessed with two different, commonly employed stimulus protocols. Additionally, concentration-response functions for each salt were measured in 37 neurons. Cells were characterized by their best response to (in M) 0. 03 NaCl, 0.1 sucrose, 0.003 HCl, 0.001 quinine hydrochloride, and 0. 1 KCl. In neurons classified as NaCl-best, amiloride reversibly blocked responses to both NaCl and KCl. In neurons classified as HCl-best, amiloride had no effect on either stimulus. In sucrose-best neurons, amiloride blocked the response to NaCl but not KCl. These results support the hypothesis that both salts are transduced by at least two different receptor mechanisms. In the NST, information arising from these different inputs is maintained in discrete populations of neurons. In addition to differences in amiloride sensitivity, the cell types also differed in their responses to the salts across concentration. At midrange salt concentrations, NaCl-best neurons were far more responsive to NaCl than KCl, whereas HCl- and sucrose-best neurons responded equivalently to the two salts at all concentrations. Because NaCl- and HCl-best cells cannot by themselves distinguish NaCl from KCl, it is the relative activity across these cell types that comprises the code for taste discrimination. PMID:10368384

  18. Effect of molecular structure on the conductivity of amorphous carbohydrate-water-KCl mixtures in the supercooled liquid state.

    PubMed

    Noel, Timothy R; Parker, Roger; Ring, Stephen G

    2003-02-14

    The effect of carbohydrate structure on the conductivity of low water content amorphous carbohydrate-water, and carbohydrate-water-KCl mixtures, has been measured using both direct current and alternating current techniques at temperatures in the supercooled liquid and glassy range, ranging from -40 to 80 degrees C. The structures included homologous mono-, di- and trisaccharides (glucose, maltose and maltotriose), a monosaccharide with no exocyclic hydroxymethyl group (xylose) and a second trisaccharide (raffinose). The KCl-mixtures contained 9.3% w/w water and 0.74% w/w KCl which resulted in calorimetric glass transition temperatures, T(g), in the range -29-19 degrees C. At this concentration conduction due to KCl dominated that due to intrinsic conductors originating from the carbohydrates and water. In the supercooled liquid region, as temperature, T, is reduced to T(g), the activation energy of the molar conductivity of KCl, Lambda(m), increased as described by a Vogel-Tamman-Fulcher-type equation, Lambda(m)=Lambda(m0)exp[B/(T-T(0))], where Lambda(m0), B and T(0) are constants. Comparison of the molar conductivity of KCl in the carbohydrate mixtures at T(g) with that in aqueous solutions showed that conductivity is, to varying extents, uncoupled from viscosity. The uncoupling increased in the order D-xylose

  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. SINGLE PARTICLE SPECTRA ASSOCIATED WITH HIGH-MULTIPLICITY EVENTS IN 800 MeV/ NUCLEON Ar ON KCl AND Pb

    SciTech Connect

    Nagamiya, S.; Lemaire, M.-C.; Schnetzer, S.; Steiner, H.; Tanihata, I.

    1980-03-01

    High-multiplicity events were selected in collisions of 800 MeV per nucleon Ar on KCl and Pb. In these events projectile fragments are highly suppressed, and the angular distributions of high-energy protons are almost isotropic in a moving frame whose rapidity is y{sub 0} ( y{sub 0} ~ 0.60 for KCl and 0.43 for Pb targets). Comparisons with inclusive proton data are used to estimate the relative importance of single and multiple NN collisions. Pion spectra in high-multiplicity events are also presented.

  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. Corrosion resistance of steel materials in LiCl-KCl melts

    NASA Astrophysics Data System (ADS)

    Wang, Le; Li, Bing; Shen, Miao; Li, Shi-yan; Yu, Jian-guo

    2012-10-01

    The corrosion behaviors of 304SS, 316LSS, and Q235A in LiCl-KCl melts were investigated at 450°C by Tafel curves and electrochemical impedance spectroscopy (EIS). 316LSS shows the best corrosion resistance behaviors among the three materials, including the most positive corrosion potential and the smallest corrosion current from the Tafel curves and the largest electron transfer resistance from the Nyquist plots. The results are in good agreement with the weight losses in the static corrosion experiments for 45 h. This may be attributed to the better corrosion resistance of Mo and Ni existing as alloy elements in 316LSS, which exhibit the lower corrosion current densities and more positive corrosion potentials than 316LSS in the same melts.

  3. Semiconductor- to metallic-like behavior in Bi thin films on KCl substrate

    NASA Astrophysics Data System (ADS)

    Bui, Thanh Nhan; Raskin, Jean-Pierre; Hackens, Benoit

    2016-04-01

    Bi thin films, with a thickness of 100 nm, are deposited by electron-beam evaporation on a freshly cleaved (100) KCl substrate. The substrate temperature during film growth (Tdep) ranges from room temperature up to 170 °C. Films deposited at room temperature exhibit a maze-like microstructure typical of the rhombohedral (110) texture, as confirmed by X-ray diffraction. For Tdep above 80 °C, a different microstructure appears, characterized by concentric triangular shapes corresponding to the trigonal (111) texture. Temperature dependence of the resistivity shows a transition from a semiconductor-like behavior for films deposited at room temperature to a metallic-like behavior for Tdep above 80 °C. From magnetoresistance measurements between room temperature and 1.6 K, we extract the electron and hole mobilities, concentrations, and mean free paths, which allow to draw a complete picture of the transport properties of both types of films.

  4. 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.

  5. Plutonium chemical properties in NaCl-KCl and CaCl 2 at 1073 K

    NASA Astrophysics Data System (ADS)

    Lambertin, David; Ched'homme, Séverine; Bourgès, Gilles; Sanchez, Sylvie; Picard, Gérard

    2005-05-01

    The electrochemical properties of plutonium have been studied in molten equimolar NaCl/KCl and CaCl2 at 1073 K by cyclic voltammetry. The respective standard potentials of Pu(III)/Pu redox couple, -2.54 V and -2.51 V (versus Cl-/Cl2 reference electrode), led to the calculation of the activity coefficients of Pu(III) in each electrolyte. In CaCl2 the complexation of Pu(III) ions is lower and the voltage gap between Pu(III)/Pu redox system and the solvent limit is higher. Use of these results to construct potential-pO2- diagrams for plutonium at 1073 K gives a rational overview of plutonium properties in these media.

  6. 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.

  7. Oxidative stability and antioxidant enzyme activities of dry-cured bacons as affected by the partial substitution of NaCl with KCl.

    PubMed

    Wu, Haizhou; Yan, Wenjing; Zhuang, Hong; Huang, Mingming; Zhao, Jianying; Zhang, Jianhao

    2016-06-15

    This study investigated the influence of partial substitution of NaCl with KCl on protein and lipid oxidation as well as antioxidant enzyme activities in dry-cured bacons during processing. The partial substitution was 0% KCl (I), 40% KCl (II), and 70% KCl (III). Compared with 0% KCl (I), the substitution of 40% NaCl with KCl did not significantly influence the protein and lipid oxidation and antioxidant enzyme activities. The bacons that were treated with 70% KCl treatment (III) showed increased lipid oxidation and antioxidant enzyme GSH-Px activity, whereas samples treated with formulas I and II showed higher protein oxidation and antioxidant enzyme catalase activity. These results demonstrate that the substitution of NaCl with KCl by more than 40% may significantly affect protein and lipid oxidation and that for the substitution of NaCl in further processed meat products with other chloride salts, salt content is very important for control of protein and lipid biochemical changes in finished products. PMID:26868571

  8. Densities of L-Glutamic Acid HCl Drug in Aqueous NaCl and KCl Solutions at Different Temperatures

    NASA Astrophysics Data System (ADS)

    Ryshetti, Suresh; Raghuram, Noothi; Rani, Emmadi Jayanthi; Tangeda, Savitha Jyostna

    2016-04-01

    Densities (ρ ) of (0.01 to 0.07) {mol}{\\cdot } {kg}^{-1} L-Glutamic acid HCl (L-HCl) drug in water, and in aqueous NaCl and KCl (0.5 and 1.0) {mol}{\\cdot } {kg}^{-1} solutions have been reported as a function of temperature at T = (298.15, 303.15, 308.15, and 313.15) K and atmospheric pressure. The accurate density (ρ ) values are used to estimate the various parameters such as the apparent molar volume (V_{2,{\\upphi }}), the partial molar volume (V2^{∞}), the isobaric thermal expansion coefficient (α 2), the partial molar expansion (E2^{∞}), and Hepler's constant (partial 2V2^{∞}/partial T2)P. The Cosphere overlap model is used to understand the solute-solvent interactions in a ternary mixture (L-HCl drug + NaCl or KCl + water). Hepler's constant (partial 2V2^{∞}/partial T2)_P is utilized to interpret the structure-making or -breaking ability of L-HCl drug in aqueous NaCl and KCl solutions, and the results are inferred that L-HCl drug acts as a structure maker, i.e., kosmotrope in aqueous NaCl solutions and performs as a structure breaker, i.e., chaotrope in aqueous KCl solutions.

  9. 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.

  10. 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 β-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 μM 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 μM 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 μM 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

  11. Acidity constants in different media (I=0 and I=0.1 M KCl) from the uncertainty perspective.

    PubMed

    Koort, Eve; Gans, Peter; Herodes, Koit; Pihl, Viljar; Leito, Ivo

    2006-07-01

    Procedures for estimating the measurement uncertainty for the acidity constant Ka (or the pKa value) in different media (I=0 and I=0.1 mol L(-1) KCl), as determined by potentiometric titration, are presented. The uncertainty budgets (the relative contributions of the different input quantities to the uncertainty in the result) of the pKa (I=0) and pKa (I=0.1 mol L(-1) KCl) values are compared. Unlike the values themselves, the uncertainties and uncertainty budgets of the values are comparable. The uncertainty estimation procedures are based on mathematical models of pKa measurement and involve the identification and quantification of individual uncertainty sources according to the ISO GUM approach. The mathematical model involves 52 and 48 input parameters for pKa (I=0) and pKa (I=0.1 mol L(-1) KCl), respectively. The relative importance of each source of uncertainty is discussed. In both cases, the main contributors to the uncertainty budget are the uncertainty components due to the hydrogen ion concentration/activity measurement, which provide 63.7% (for pKa (I=0)) and 89.3% (for pKa (I=0.1 mol L(-1) KCl)) of the uncertainty. The remaining uncertainty contributions arise mostly from the limited purity of the acid. From this work, it is clear that the uncertainties of the pKa (I=0.1 mol L(-1) KCl) values tend to be lower than those of the pKa (I=0) values. The main reasons for this are that: (1) the uncertainty due to the residual liquid junction potential is nominally absent in the case of pKa (I=0.1 mol L(-1) KCl) due to the similarly high concentrations of background electrolyte in the calibration solutions and measured solution; (2) the electrode system is more stable in solutions containing the 0.1 mol L(-1) KCl background electrolyte and so the readings obtained in these solutions are more stable. PMID:16791552

  12. High-pressure experimental growth of diamond using C-K 2CO 3-KCl as an analogue for Cl-bearing carbonate fluid

    NASA Astrophysics Data System (ADS)

    Tomlinson, Emma; Jones, Adrian; Milledge, Judith

    2004-09-01

    High-pressure, high-temperature diamond growth experiments have been conducted in the system C-K 2CO 3-KCl at 1050-1420 °C, 7.0-7.7 GPa. KCl is of interest because of the strong effect of halogens on the phase relations of carbonate-rich systems [Geophys. Res. Lett. 30 (2003) 1022] and because of the occurrence of KCl coexisting with alkali silicate-carbonate fluids in natural-coated diamond [Geochim. Cosmochim. Acta 64 (2000) 717]. We have used system C-K 2CO 3-KCl as an analogue for these mantle fluids in diamond growth experiments. The presence of KCl reduces the potassium carbonate liquidus to ≤1000 °C at 7.7 GPa, allowing it to act as a solvent catalyst for diamond growth at temperatures below the continental geotherm. This is a reduction on the minimum diamond growth temperature reported in the alkali-carbonate-C-O-H system [Lithos 60 (2002) 145]. Diamond growth using carbonate solvent catalysts is characterised by a relatively long induction period. However, the addition of KCl also reduced the period for diamond growth in carbonate to ≪5 min; no such induction period appears to be necessary. It is suggested that KCl destabilises carbonate, allowing greater solubility and diffusion of carbon.

  13. Corrosion and Microstructure Correlation in Molten LiCl-KCl Medium

    NASA Astrophysics Data System (ADS)

    Ravi Shankar, A.; Mathiya, S.; Thyagarajan, K.; Kamachi Mudali, U.

    2010-07-01

    Pyrochemical reprocessing in molten chloride salt medium has been considered as one of the best options for the reprocessing of spent metallic fuels of future fast breeder reactors. The unit operations such as salt preparation, electrorefining, and cathode processing involve the presence of molten LiCl-KCl eutectic salt from 673 to 1373 K (400 to 1100 °C). The present work discusses the corrosion behavior of electroformed nickel (EF Ni) without and with nickel-tungsten (Ni-W) coating, 316L SS, and INCONEL 625 alloy in molten LiCl-KCl eutectic salt at 673 K, 773 K, and 873 K (400 °C, 500 °C, and 600 °C) in the presence of air. The weight percent loss of the exposed samples was determined by the weight loss method and surface morphology of the salt exposed, and product layers were examined by scanning electron microscopy (SEM). X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) analysis were also carried out on the exposed and corrosion product layers to understand the phases present and the corrosion mechanism involved. The results of the present study indicated that INCONEL 625 alloy showed superior corrosion resistance compared to electroformed nickel (EF Ni), EF Ni with nickel-tungsten (Ni-W) coating (EF Ni-W), and 316L SS. The EF Ni with Ni-W coating exhibits better corrosion resistance than EF Ni without tungsten coating. Based on the surface morphology, XRD, and EDX analysis of corrosion product layers, the mechanism of corrosion of INCONEL 625 and 316L involves formation of chromium-rich compound at the surface and subsequent spallation. For the EF Ni, the porous thick NiO corrosion product allows the penetration of salt, thus accelerating the corrosion. Improved corrosion resistance of EF Ni-W was attributed to the W-rich NiO layer, while for INCONEL 625, the adherent and protective NiO layer improved the corrosion resistance. The article highlights the results of the present investigation.

  14. Swelling activation of K-Cl cotransport in LK sheep erythrocytes: a three-state process

    PubMed Central

    1993-01-01

    K-Cl cotransport in LK sheep erythrocytes is activated by osmotic swelling and inhibited by shrinkage. The mechanism by which changes in cell volume are transduced into changes in transport was investigated by measuring time courses of changes in transport after osmotic challenges in cells with normal and reduced Mg concentrations. When cells of normal volume and normal Mg are swollen, there is a delay of 10 min or more before the final steady-state flux is achieved, as there is for swelling activation of K-Cl cotransport in erythrocytes of other species. The delay was shown to be independent of the extent of swelling. There was also a delay after shrinkage inactivation of cotransport. Reducing cellular Mg concentration activates cotransport. Swelling of low-Mg cells activates cotransport further, but with no measurable delay. In contrast, there is a delay in shrinkage inactivation of cotransport in low-Mg cells. The results are interpreted in terms of a three-state model: [formula see text] in which A state, B state, and C state transporters have relatively slow, intermediate, and fast transport rates, respectively. Most transporters in shrunken cells with normal Mg are in the A state. Swelling converts transporters to the B state in the rate-limiting process, followed by rapid conversion to the C state. Reducing cell Mg also promotes the A-- >B conversion. Swelling of low-Mg cells activates transport rapidly because of the initial predominance of B state transporters. The results support the following conclusions about the rate constants of the three-state model: k21 is the rate constant for a Mg-promoted process that is inhibited by swelling; k12 is not volume sensitive. Both k23 and k32 are increased by swelling and reduced by shrinkage; they are rate constants for a single process, whereas k12 and k21 are rate constants for separate processes. Finally, the A-->B conversion entails an increase in Jmax of the transporters, and the B-->C conversion entails an increase in the affinity of the transporters for K. PMID:8336103

  15. Local structures and the dissolving behavior of aqueous ammonia and its KCl and NH4Cl solutions: A Raman spectroscopy and X-ray scattering study.

    PubMed

    Li, Shenyu; Yuan, Junsheng; Li, Fei; Liu, Ziyu

    2016-06-01

    The aqueous ammonia (5%-15%) and its KCl and NH4Cl solutions have been studied by Raman spectroscopy and X-ray scattering. The microscopic structures in these solutions were proposed. The addition of KCl reinforced the hydrogen bond between NH3 and H2O. On contrary, NH4Cl destroyed this interaction by forming hydrogen bond NH4(+)-NH3. This study gave an interpretation of the different dissolving behavior of KCl and NH4Cl in aqueous ammonia, which may have important implications in the separation of potassium and ammonium salt during the industrial production. PMID:26974475

  16. Sites of Regulated Phosphorylation that Control K-Cl Cotransporter Activity

    PubMed Central

    Rinehart, Jesse; Maksimova, Yelena D.; Tanis, Jessica E.; Stone, Kathryn L.; Hodson, Caleb A.; Zhang, Junhui; Risinger, Mary; Pan, Weijun; Wu, Dianqing; Colangelo, Christopher M.; Forbush, Biff; Joiner, Clinton H.; Gulcicek, Erol E.; Gallagher, Patrick G.; Lifton, Richard P.

    2010-01-01

    Summary Modulation of intracellular chloride concentration ([Cl−]i) plays a fundamental role in cell volume regulation and neuronal response to GABA. Cl− exit via K-Cl cotransporters (KCCs) is a major determinant of [Cl−]I; however, mechanisms governing KCC activities are poorly understood. We identified two sites in KCC3 that are rapidly dephosphorylated in hypotonic conditions in cultured cells and human red blood cells in parallel with increased transport activity. Alanine substitutions at these sites result in constitutively active cotransport. These sites are highly phosphorylated in plasma membrane KCC3 in isotonic conditions, suggesting that dephosphorylation increases KCC3's intrinsic transport activity. Reduction of WNK1 expression via RNA interference reduces phosphorylation at these sites. Homologous sites are phosphorylated in all human KCCs. KCC2 is partially phosphorylated in neonatal mouse brain and dephosphorylated in parallel with KCC2 activation. These findings provide insight into regulation of [Cl−]i and have implications for control of cell volume and neuronal function. PMID:19665974

  17. Sites of regulated phosphorylation that control K-Cl cotransporter activity.

    PubMed

    Rinehart, Jesse; Maksimova, Yelena D; Tanis, Jessica E; Stone, Kathryn L; Hodson, Caleb A; Zhang, Junhui; Risinger, Mary; Pan, Weijun; Wu, Dianqing; Colangelo, Christopher M; Forbush, Biff; Joiner, Clinton H; Gulcicek, Erol E; Gallagher, Patrick G; Lifton, Richard P

    2009-08-01

    Modulation of intracellular chloride concentration ([Cl(-)](i)) plays a fundamental role in cell volume regulation and neuronal response to GABA. Cl(-) exit via K-Cl cotransporters (KCCs) is a major determinant of [Cl(-)](I); however, mechanisms governing KCC activities are poorly understood. We identified two sites in KCC3 that are rapidly dephosphorylated in hypotonic conditions in cultured cells and human red blood cells in parallel with increased transport activity. Alanine substitutions at these sites result in constitutively active cotransport. These sites are highly phosphorylated in plasma membrane KCC3 in isotonic conditions, suggesting that dephosphorylation increases KCC3's intrinsic transport activity. Reduction of WNK1 expression via RNA interference reduces phosphorylation at these sites. Homologous sites are phosphorylated in all human KCCs. KCC2 is partially phosphorylated in neonatal mouse brain and dephosphorylated in parallel with KCC2 activation. These findings provide insight into regulation of [Cl(-)](i) and have implications for control of cell volume and neuronal function. PMID:19665974

  18. 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.

  19. Direct measurement of potassium leak from single 3 M KCl microelectrodes.

    PubMed

    Stoner, L C; Natke, E; Dixon, M K

    1984-03-01

    Potassium loss was measured from individual microelectrodes filled with 3 M KCl. The potassium content of a distilled-water droplet into which a microelectrode was inserted for a known time interval was analyzed by helium-glow photometry. The rate of potassium loss from single microelectrodes (18-97 M omega) was within the detectable limits of this method. The rate of potassium loss appeared to decrease with increasing input resistance (determined in 0.16 M NaCl) for electrodes having a low resistance (18-50 M omega). Higher resistance electrodes (greater than 50 M omega) appeared to achieve a uniform rate of potassium loss of 3.5 fmol X s-1. Estimates of the rate of potassium loss calculated from the rate of swelling of impaled cells were identical to those measured directly on the same group of electrodes. We conclude the electrolyte loss not only occurs into a distilled-water drop but also during intracellular recording. An alternative method for fabrication of microelectrodes was tested. Of these electrodes, the ones having an input resistance greater than 50 M omega lost potassium at rates below 1 fmol X s-1. PMID:6703067

  20. Adsorption-induced changes of intramolecular optical transitions: PTCDA/NaCl and PTCDA/KCl.

    PubMed

    Hochheim, Manuel; Bredow, Thomas

    2015-09-15

    Structural and optical properties of isolated perylene-3,4,9,10-tetracarboxylic acid dianhydride molecules adsorbed on (100) oriented NaCl and KCl surfaces were studied theoretically to analyze the recently observed red-shift of the optical excitation spectrum after adsorption (Mller et al., Phys. Rev. B, 2011, 83, 241203; Paulheim et al. Phys. Chem. Chem. Phys., 2013, 15, 4906). The ground-state structures were obtained by periodic dispersion-corrected density functional theory (DFT) calculations. For the excited-state calculations, nonperiodic time-dependent DFT methods were applied for a cluster model embedded in point charges. The range-separated hybrid functional CAM-B3LYP was used. Correlation-consistent basis sets were used and the calculated excitation energies were extrapolated to the complete basis set limit. The shift of the first optical excitation energy was analyzed in terms of electronic and geometric contributions. It was found that both the distortion of the molecule due to the interaction with the surface and the electrostatic potential of the surface play an important role. PMID:26152591

  1. Methanol extracts of Hamelia patens containing oxindole alkaloids relax KCl-induced contraction in rat myometrium.

    PubMed

    Reyes-Chilpa, Ricardo; Rivera, Jesús; Oropeza, Martha; Mendoza, Pilar; Amekraz, Badia; Jankowski, Christopher; Campos, Maria

    2004-10-01

    Hamelia patens JAQC. (Rubiaceae) is a medicinal bush widely distributed in tropical areas of the American continent. It is used in Mexican Traditional Medicine for the treatment of menstrual disorders, therefore suggesting that its chemical constituents may have some effect on myometrium contractility. Physiological effects might differ due to quantitative variations in the content of alkaloids arising from its wide geographical distribution. To test this hypothesis, the content of oxindole alkaloids in methanol extracts of five different samples collected in Mexico was quantified by GC-MS. Each extract was assayed on contractility of estrogen-primed rat myometrium. Variations in the content of alkaloids were observed among the different samples. All samples relaxed in a concentration-dependent manner the high KCl-induced contraction in rat myometrium. Those which lack rumberine and/or maruquine displayed a higher relaxant effect than samples containing them, suggesting that these alkaloids might counteract the effects of isopteropodine. However, in contrast with verapamil, Hamelia patens metanol extracts are poor relaxants. PMID:15467206

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

    SciTech Connect

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

    2015-06-15

    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.

  3. Electrochemical formation of Al-Tm intermetallics in eutectic LiCl-KCl melt containing Tm and Al ions

    NASA Astrophysics Data System (ADS)

    Li, Xing; Yan, Yong-De; Zhang, Mi-Lin; Tang, Hao; Ji, De-Bin; Han, Wei; Xue, Yun; Zhang, Zhi-Jian

    2014-09-01

    This work focuses on investigating the electrochemical formation of Al-Tm and Al-Li-Tm alloys in LiCl-KCl-AlCl3-Tm2O3 melt on both W and Al electrodes. Thermodynamic calculation and electrochemical behavior of LiCl-KCl melt containing both AlCl3 and Tm2O3 showed that AlCl3 can chlorinate Tm2O3 to release Tm(III) ions. Three kinds of Al-Tm intermetallics at about -1.26, -1.32 and -1.43 V were detected by means of various electrochemical measurement techniques, i.e. cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry. Potentiostatic and galvanostatic electrolysis were carried out on Al and W electrodes to prepare Al-Tm and Al-Li-Tm alloys, respectively. The composition of Al-Li-Tm alloys was analyzed by inductive coupled plasma atomic emission spectrometer (ICP-AES).

  4. Electrolytic LiCl precipitation from LiCl-KCl melt in porous Li-Al anodes

    NASA Astrophysics Data System (ADS)

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

    1983-12-01

    Composition gradients such as those predicted to occur during discharge of porous Li-Al negative electrodes of Li/S batteries with LiCl-KCl eutectic electrolyte were generated and measured in the LiCl-KCl anolyte of an electrolysis cell with Li-Al electrodes. Precipitation of lithium chloride during electrolysis was observed by two-dimensional scanning of electrolyte composition in the front part of quenched porous Li-Al anode sections using SEM/EDX. The distribution of sites of increased or decreased LiCl concentration, LiCl saturation and precipitation was mapped. Cathodic regions were observed near the cell walls. Preliminary results of analysis by Auger spectroscopy confirm LiCl precipitation in the porous anode.

  5. Equilibrium between titanium ions and high-purity titanium electrorefining in a NaCl-KCl melt

    NASA Astrophysics Data System (ADS)

    Song, Jian-xun; Wang, Qiu-yu; Hu, Guo-jing; Zhu, Xiao-bo; Jiao, Shu-qiang; Zhu, Hong-min

    2014-07-01

    TiCl x ( x = 2.17) was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiCl x melt was employed as the electrolyte, and two parallel crude titanium plates and one high-purity titanium plate were used as the anode and cathode, respectively. A series of electrochemical tests were performed to investigate the influence of electrolytic parameters on the current efficiency and quality of cathodic products. The results indicated that the quality of cathodic products was related to the current efficiency, which is significantly dependent on the current density and the initial concentration of titanium ions. The significance of this study is the attainment of high-purity titanium with a low oxygen content of 30 × 10-6.

  6. 17β-Estradiol relaxes cholecystokinin- and KCl-induced tension in male guinea pig gallbladder strips.

    PubMed

    Kline, Loren W; Karpinski, Edward

    2011-05-01

    Estrogen has been shown to have an inhibitory effect on the contractility of gastrointestinal smooth muscle, including the gallbladder. Since estrogen and progesterone levels are elevated during pregnancy, a biliary stasis may develop during pregnancy that is characterized by an increase in the fasting and residual volumes and by a decrease in emptying capacity. This study investigates the effect of 17β-estradiol (E2) on contraction in male guinea pig gallbladder strips. E2 induced a concentration-dependent relaxation of either CCK-induced tension or KCl-induced tension. Pretreatment of the strips with PKA inhibitor 14-22 amide myristolated had no significant effect on the E2-induced relaxation. Pretreatment of strips with 2-APB, and inhibitor of IP(3) induced Ca(2+) release, produced a significant (p<0.001) increase in the amount of E2-induced relaxation when either CCK or KCl were used to induce tension. KT5823, an inhibitor of PKG, also significantly (p<0.001) increased the amount of E2-induced relaxation. Genistein, an inhibitor of protein tyrosine kinase, had no significant effect on the E2-induced relaxation. Bisindolymaleimide IV and chelerythrine Cl- when used in combination had no significant effect on the amount of CCK-induced tension, but significantly (p<0.001) increased the amount of E2-induced relaxation. When E2 was added to the chambers prior to either CCK or KCl, a significant decrease (p<0.001) in the amount of tension generated was observed. The inhibition of extracellular Ca(2+) entry mediates the E2-induced relaxation of CCK- and KCl-induced tension in male guinea pig gallbladder strips. PMID:21335018

  7. Generation of KCL013 research grade human embryonic stem cell line carrying a mutation in the HTT gene

    PubMed Central

    Jacquet, Laureen; Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL013 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation affecting one allele of the HTT gene encoding huntingtin (42 trinucleotide repeats; 17 for the normal allele). The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  8. 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.%.

  9. Generation of KCL035 research grade human embryonic stem cell line carrying a mutation in HBB gene

    PubMed Central

    Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL035 human embryonic stem cell line was derived from an embryo donated for research that carried a mutation in the HBB gene, which is linked to the β-thalassemia syndrome. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  10. The effects of beta-adrenoceptor agonists on KCl-induced rhythmic contraction in the ureter of guinea pig.

    PubMed

    Yamamoto, Y; Koike, K

    2000-02-01

    In the present study, we tried to determine what effects were induced by beta-adrenoceptor agonists on 40 mM KCl-induced rhythmic contraction and to clarify which beta-adrenoceptor subtypes are involved in the regulation of ureter motility in the guinea pig by using in vitro functional analysis. 40 mM KCl-induced rhythmic contraction was abolished by papaverine (10(-6) M), nicardipine (10(-5) M) and cromakalim (10(-5) M), but was not influenced by atropine (10(-6) M). Isoprenaline decreased the amplitude, and changed the pattern of 40 mM KCl-induced rhythmic contraction in concentration-dependent manner. These results suggest the possibility that the stimulation of beta-adrenoceptors may regulate the ureteral peristalsis. Salbutamol (selective beta2-AR agonist) and CGP12177 (beta(1,2)-AR antagonist and beta3-AR partial agonist) were also effective in decreasing the amplitude and changing the pattern of the rhythmic contraction. The pD2 values of agonists were 7.57 (isoprenaline), 5.80 (CGP12177) and 7.63 (salbutamol), respectively. The concentration-response curves of isoprenaline and salbutamol were rightward shifted by the presence of propranolol, and the apparent pA2 values for propranolol against isoprenaline and salbutamol were 7.12 and 6.29, respectively. These results suggest that inhibition for 40 mM KCl-induced rhythmic contraction of the ureter by isoprenaline and salbutamol mediated mainly via atypical beta-adrenoceptor subtype. PMID:10830474

  11. 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 hν, 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

  12. 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.

  13. 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 χ2 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.

  14. The phase diagrams and Pitzer model representations for the system KCl + MgCl2 + H2O at 50 and 75°C

    NASA Astrophysics Data System (ADS)

    Yang, Ji-min; Peng, Jing; Duan, Yu-xia; Tian, Chong; Ping, Mei

    2012-12-01

    The solubilities in the KCl-MgCl2-H2O system were determined at 50 and 75°C and the phase diagrams and the diagram of refractive index vs composition were plotted. Two invariant point, three univariant curves, and three crystallization zones, corresponding to potassium chloride, hexahydrate (MgCl2 · 6H2O) and double salt (KCl · MgCl2 · 6H2O) showed up in the phase diagrams of the ternary system, The mixing parameters θK, Ca and ΨK, Ca, Cl and equilibrium constant K sp were evaluated in KCl-MgCl2-H2O system by least-squares optimization procedure, in which the single-salt Pitzer parameters of KCl and MgCl2 β(0), β(1), β(2), and C ϕ were directly calculated from the literature. The results obtained were in good agreement with the experimental data.

  15. Synthesis, characterization and antimicrobial activity of copper and zinc-doped hydroxyapatite nanopowders

    NASA Astrophysics Data System (ADS)

    Stanić, Vojislav; Dimitrijević, Suzana; Antić-Stanković, Jelena; Mitrić, Miodrag; Jokić, Bojan; Plećaš, Ilija B.; Raičević, Slavica

    2010-08-01

    Antimicrobial materials based on hydroxyapatite are potentially attractive in a wide variety of medical applications. The synthesis of copper and zinc-doped hydroxyapatite was done by neutralization method. This method consists of dissolving CuO or ZnO in solution of H 3PO 4, and the slow addition to suspension of Ca(OH) 2 for obtaining monophasic product. Characterization studies from XRD, SEM, TEM and FTIR spectra showed that particles of all samples are of nano size and they do not contain any discernible crystalline impurity. The quantitative elemental analysis showed that the copper and zinc ions fully incorporated into the hydroxyapatite. The antimicrobial effects of doped hydroxyapatite powders against pathogen bacterial strains Escherichia coli, Staphylococcus aureus and pathogen yeast Candida albicans were tested in solid and liquid media. Quantitative test in liquid media clearly showed that copper and zinc-doped samples had viable cells reduction ability for all tested strains.

  16. 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 (α -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.

  17. K-Cl cotransporter gene expression during human and murine erythroid differentiation.

    PubMed

    Pan, Dao; Kalfa, Theodosia A; Wang, Daren; Risinger, Mary; Crable, Scott; Ottlinger, Anna; Chandra, Sharat; Mount, David B; Hübner, Christian A; Franco, Robert S; Joiner, Clinton H

    2011-09-01

    The K-Cl cotransporter (KCC) regulates red blood cell (RBC) volume, especially in reticulocytes. Western blot analysis of RBC membranes revealed KCC1, KCC3, and KCC4 proteins in mouse and human cells, with higher levels in reticulocytes. KCC content was higher in sickle versus normal RBC, but the correlation with reticulocyte count was poor, with inter-individual variability in KCC isoform ratios. Messenger RNA for each isoform was measured by real time RT-quantitative PCR. In human reticulocytes, KCC3a mRNA levels were consistently the highest, 1-7-fold higher than KCC4, the second most abundant species. Message levels for KCC1 and KCC3b were low. The ratios of KCC RNA levels varied among individuals but were similar in sickle and normal RBC. During in vivo maturation of human erythroblasts, KCC3a RNA was expressed consistently, whereas KCC1 and KCC3b levels declined, and KCC4 message first increased and then decreased. In mouse erythroblasts, a similar pattern for KCC3 and KCC1 expression during in vivo differentiation was observed, with low KCC4 RNA throughout despite the presence of KCC4 protein in mature RBC. During differentiation of mouse erythroleukemia cells, protein levels of KCCs paralleled increasing mRNA levels. Functional properties of KCCs expressed in HEK293 cells were similar to each other and to those in human RBC. However, the anion dependence of KCC in RBC resembled most closely that of KCC3. The results suggest that KCC3 is the dominant isoform in erythrocytes, with variable expression of KCC1 and KCC4 among individuals that could result in modulation of KCC activity. PMID:21733850

  18. Motor protein-dependent membrane trafficking of KCl cotransporter-4 is important for cancer cell invasion

    PubMed Central

    Chen, Yih-Fung; Chou, Cheng-Yang; Wilkins, Robert J.; Ellory, J. Clive; Mount, David B.; Shen, Meng-Ru

    2009-01-01

    The KCl cotransporter (KCC) is a major determinant of osmotic homeostasis and plays an emerging role in tumor biology. This study stresses the important role of KCC4 in tumor malignant behavior. Real-time reverse transcription polymerase chain reaction on samples collected by laser microdissection and immunofluorescent stainings with different KCC isoform antibodies indicate that KCC4 is abundant in metastatic cervical and ovarian cancer tissues. Insulin-like growth factor 1 (IGF-1) and epidermal growth factor (EGF) stimulate KCC4 recruitment from a presumably inactive cytoplasmic pool of endoplasmic reticulum and Golgi to plasma membrane along actin cytoskeleton that is significantly inhibited by LY294002 and wortmannin. Throughout the trafficking process, KCC4 is incorporated into lipid rafts that function as a platform for the association between KCC4 and myosin Va, an actin-dependent motor protein. KCC4 and ezrin, a membrane cytoskeleton linker, colocalize at lamellipodia of migratory cancer cells. Interference with KCC activity by either the inhibitor or a dominant-negative loss-of-function mutant profoundly suppressed the IGF-1-induced membrane trafficking of KCC4 and structural interaction between KCC4 and ezrin near surface. Endogenous cancer cell invasiveness was significantly attenuated by small interfering RNA targeting KCC4 and the residual invasiveness was much less sensitive to IGF-1 or EGF stimulation. In the metastatic cancer tissues, KCC4 colocalizes with IGF-1 or EGF, indicating a likely in vivo stimulation of KCC4 function by growth factors. Thus, blockade of KCC4 trafficking and surface expression may provide a potential target for the prevention of IGF-1 or EGF-dependent cancer spread. PMID:19887603

  19. Molecular evidence for a role for K(+)-Cl(-) cotransporters in the kidney.

    PubMed

    Melo, Zesergio; Cruz-Rangel, Silvia; Bautista, Rocio; Vázquez, Norma; Castañeda-Bueno, María; Mount, David B; Pasantes-Morales, Herminia; Mercado, Adriana; Gamba, Gerardo

    2013-11-15

    K(+)-Cl(-) cotransporter (KCC) isoforms 3 (KCC3) and 4 (KCC4) are expressed at the basolateral membrane of proximal convoluted tubule cells, and KCC4 is present in the basolateral membrane of the thick ascending loop of Henle's limb and α-intercalated cells of the collecting duct. Little is known, however, about the physiological roles of these transporters in the kidney. We evaluated KCC3 and KCC4 mRNA and protein expression levels and intrarenal distribution in male Wistar rats or C57 mice under five experimental conditions: hyperglycemia after a single dose of streptozotocin, a low-salt diet, metabolic acidosis induced by ammonium chloride in drinking water, and low- or high-K(+) diets. Both KCC3 mRNA and protein expression were increased during hyperglycemia in the renal cortex and at the basolateral membrane of proximal tubule cells but not with a low-salt diet or acidosis. In contrast, KCC4 protein expression was increased by a low-sodium diet in the whole kidney and by metabolic acidosis in the renal outer medulla, specifically at the basolateral membrane of α-intercalated cells. The increased protein expression of KCC4 by a low-salt diet was also observed in WNK4 knockout mice, suggesting that upregulation of KCC4 in these circumstances is not WNK4 dependent. No change in KCC3 or KCC4 protein expression was observed under low- or high-K(+) diets. Our data are consistent with a role for KCC3 in the proximal tubule glucose reabsorption mechanism and for KCC4 in salt reabsorption of the thick ascending loop of Henle's loop and acid secretion of the collecting duct. PMID:24089410

  20. Kinetics of the B1-B2 phase transition in KCl under rapid compression

    NASA Astrophysics Data System (ADS)

    Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; Park, Changyong; Kono, Yoshio; Kenney-Benson, Curtis; Rod, Eric; Shen, Guoyin

    2016-01-01

    Kinetics of the B1-B2 phase transition in KCl has been investigated under various compression rates (0.03-13.5 GPa/s) in a dynamic diamond anvil cell using time-resolved x-ray diffraction and fast imaging. Our experimental data show that the volume fraction across the transition generally gives sigmoidal curves as a function of pressure during rapid compression. Based upon classical nucleation and growth theories (Johnson-Mehl-Avrami-Kolmogorov theories), we propose a model that is applicable for studying kinetics for the compression rates studied. The fit of the experimental volume fraction as a function of pressure provides information on effective activation energy and average activation volume at a given compression rate. The resulting parameters are successfully used for interpreting several experimental observables that are compression-rate dependent, such as the transition time, grain size, and over-pressurization. The effective activation energy (Qeff) is found to decrease linearly with the logarithm of compression rate. When Qeff is applied to the Arrhenius equation, this relationship can be used to interpret the experimentally observed linear relationship between the logarithm of the transition time and logarithm of the compression rates. The decrease of Qeff with increasing compression rate results in the decrease of the nucleation rate, which is qualitatively in agreement with the observed change of the grain size with compression rate. The observed over-pressurization is also well explained by the model when an exponential relationship between the average activation volume and the compression rate is assumed.

  1. K-Cl Cotransporter Gene Expression during Human and Murine Erythroid Differentiation*

    PubMed Central

    Pan, Dao; Kalfa, Theodosia A.; Wang, Daren; Risinger, Mary; Crable, Scott; Ottlinger, Anna; Chandra, Sharat; Mount, David B.; Hübner, Christian A.; Franco, Robert S.; Joiner, Clinton H.

    2011-01-01

    The K-Cl cotransporter (KCC) regulates red blood cell (RBC) volume, especially in reticulocytes. Western blot analysis of RBC membranes revealed KCC1, KCC3, and KCC4 proteins in mouse and human cells, with higher levels in reticulocytes. KCC content was higher in sickle versus normal RBC, but the correlation with reticulocyte count was poor, with inter-individual variability in KCC isoform ratios. Messenger RNA for each isoform was measured by real time RT-quantitative PCR. In human reticulocytes, KCC3a mRNA levels were consistently the highest, 1–7-fold higher than KCC4, the second most abundant species. Message levels for KCC1 and KCC3b were low. The ratios of KCC RNA levels varied among individuals but were similar in sickle and normal RBC. During in vivo maturation of human erythroblasts, KCC3a RNA was expressed consistently, whereas KCC1 and KCC3b levels declined, and KCC4 message first increased and then decreased. In mouse erythroblasts, a similar pattern for KCC3 and KCC1 expression during in vivo differentiation was observed, with low KCC4 RNA throughout despite the presence of KCC4 protein in mature RBC. During differentiation of mouse erythroleukemia cells, protein levels of KCCs paralleled increasing mRNA levels. Functional properties of KCCs expressed in HEK293 cells were similar to each other and to those in human RBC. However, the anion dependence of KCC in RBC resembled most closely that of KCC3. The results suggest that KCC3 is the dominant isoform in erythrocytes, with variable expression of KCC1 and KCC4 among individuals that could result in modulation of KCC activity. PMID:21733850

  2. 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.

  3. 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

  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. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Regulatory Effects of Ca2+ and H+ on the Rat Chorda Tympani Response to NaCl and KCl.

    PubMed

    DeSimone, John A; Phan, Tam-Hao T; Mummalaneni, Shobha; Rhyu, Mee-Ra; Heck, Gerard L; Lyall, Vijay

    2015-07-01

    Modulatory effects of pHi and [Ca(2+)]i on taste receptor cell (TRC) epithelial sodium channel (ENaC) were investigated by monitoring chorda tympani (CT) responses to NaCl and KCl at various lingual voltages, before and after lingual application of ionomycin and with 0-10mM CaCl2 in the stimulus and rinse solutions adjusted to pHo 2.0-9.7. 0.1 and 0.5M KCl responses varied continuously with voltage and were fitted to an apical ion channel kinetic model using the same parameters. ENaC-dependent NaCl CT response was fitted to the same channel model but with parameters characteristic of ENaC. A graded increase in TRC [Ca(2+)]i decreased the ENaC-dependent NaCl CT response, and inhibited and ultimately eliminated its pH sensitivity. CT responses to KCl were pHi- and [Ca(2+)]i-independent. Between ±60 mV applied lingual potential, the data were well described by a linear approximation to the nonlinear channel equation and yielded 2 parameters, the open-circuit response and the negative of the slope of the line in the CT response versus voltage plot, designated the response conductance. The ENaC-dependent NaCl CT response conductance was a linear function of the open-circuit response for all pHi-[Ca(2+)]i combinations examined. Analysis of these data shows that pHi and [Ca(2+)]i regulate TRC ENaC exclusively through modulation of the maximum CT response. PMID:25953775

  10. 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)

  11. Pressure Dependence of the Infrared-Active Phonons in the Mixed Crystal System KCl(1-x)Br(x).

    PubMed

    Ferraro, J R; Postmus, C; Mitra, S S; Hoskins, C J

    1970-01-01

    The mixed crystal system KCl(1-x)Br(x) shows a one-mode type behavior. The variation of the long-wavelength transverse optical (TO) mode frequency at 1 atm pressure can be understood in terms of the virtual crystal model. The variation of the frequency with pressure or the mole fraction x can be expressed in terms of volume change alone. The slopes of the vTO mode vs P are highest for the end numbers, and are less for intermediate values of x, and may be understood in terms of a nonlinear variation of the compressibility with x. PMID:20076127

  12. 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.

  13. Intrinsic shortening speed of temperature-jump-activated intact muscle fibers. Effects of varying osmotic pressure with sucrose and KCl.

    PubMed Central

    Gulati, J; Babu, A

    1984-01-01

    Effects of intracellular ionic strength on the isotonic contraction properties of both intact fibers and skinned fibers give insights into the cross-bridge mechanism, but presently there is fundamental disagreement in the results on the two fiber preparations. This paper, which studies the effects on contraction of varying the osmotic pressure of the bathing medium with impermeant and permeant solutes, explains the above controversy and establishes the physiological significance of the previous results on skinned fibers. Fast-twitch fibers, isolated singly from tibialis and semitendinosus muscles of frogs, were activated by a temperature-jump technique in hyperosmotic solutions with either 100 or 150 mM sucrose (impermeant), or 50 or 75 mM KCl (permeant). Intracellular ionic strength was expected to rise in these solutions from the standard value of approximately 190 to 265 mM. Cell volume and the speed of unloaded shortening both decreased with sucrose and were constant with KCl. On the other hand, isometric force decreased equally with equiosmolar addition of either solute; this is additional evidence that contractile force decreases with ionic strength and is independent of fiber volume. Therefore, for the main cross-bridges, force per bridge is constant with changes in the lateral separation between the myofilaments. The next finding, that at a fixed cell volume the contraction speed is constant with KCl, provides clear evidence in intact fibers that the intrinsic speed of shortening is insensitive to increased ionic strength. The data with KCl are in agreement with the results on skinned fibers. The results suggest that in the cross-bridge kinetics in vivo the rate-limiting step is different for force than that for shortening. On the other hand, the decrease in speed with sucrose is associated with the shrinkage in cell volume, and is explained by the possibility of an increased internal load. A major fraction of the internal load may arise from unusual interactions between the sliding filaments; these interactions are enhanced in the fibers compressed with sucrose, but this does not affect the intrinsic kinetics of the main cross-bridges. Images FIGURE 2 FIGURE 4 FIGURE 6 FIGURE 7 PMID:6607750

  14. Generation of KCL024 research grade human embryonic stem cell line carrying a mutation in NF1 gene

    PubMed Central

    Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL024 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation in the NF1 gene encoding neurofibromin (c.3739–3742 ∆ TTTG). Mutations in this gene have been linked to neurofibromatosis type 1, juvenile myelomonocytic leukemia and Watson syndrome. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  15. Generation of KCL025 research grade human embryonic stem cell line carrying a mutation in NF1 gene

    PubMed Central

    Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL025 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation in the NF1 gene encoding neurofibromin (c.3739–3742 ΔTTTG). Mutations in this gene have been linked to neurofibromatosis type 1, juvenile myelomonocytic leukemia and Watson syndrome. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  16. Generation of KCL026 research grade human embryonic stem cell line carrying a mutation in SMN1 gene

    PubMed Central

    Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL026 human embryonic stem cell line was derived from an embryo donated for research that carried a mutation in the SMN1 gene encoding survival of motor neuron 1, telomeric (exons 7 and 8 deletion). Mutations in this gene are associated with spinal muscular atrophy. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  17. Generation of KCL018 research grade human embryonic stem cell line carrying a mutation in the DMPK gene

    PubMed Central

    Miere, Cristian; Hewitson, Heema; Devito, Liani; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL018 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation affecting one allele of the DMPK gene encoding the dystrophia myotonica protein kinase (2200 trinucleotide repeats; 14 for the normal allele). The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  18. Generation of KCL017 research grade human embryonic stem cell line carrying a mutation in VHL gene

    PubMed Central

    Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL017 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation affecting splicing site of the VHL gene encoding von Hippel–Lindau tumor suppressor E3 ubiquitin protein ligase (676 + 3 A > T). The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  19. Generation of KCL016 research grade human embryonic stem cell line carrying a mutation in VHL gene

    PubMed Central

    Miere, Cristian; Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL016 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation affecting splicing site of the VHL gene encoding von Hippel–Lindau tumor suppressor E3 ubiquitin protein ligase (676 + 3A > T). The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  20. Generation of KCL028 research grade human embryonic stem cell line carrying a mutation in the HTT gene

    PubMed Central

    Jacquet, Laureen; Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Hobbs, Carl; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL028 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation affecting one allele of the HTT gene encoding huntingtin (43 trinucleotide repeats; 21 for the normal allele). The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro and in vivo assays.

  1. Generation of KCL036 research grade human embryonic stem cell line carrying a mutation in the HTT gene

    PubMed Central

    Jacquet, Laureen; Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Hobbs, Carl; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL036 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation affecting one allele of the HTT gene encoding huntingtin (38 trinucleotide repeats; 14 for the normal allele). The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro and in vivo assays.

  2. Generation of KCL012 research grade human embryonic stem cell line carrying a mutation in the HTT gene

    PubMed Central

    Jacquet, Laureen; Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Hobbs, Carl; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL012 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation affecting one allele of the HTT gene encoding huntingtin (46 trinucleotide repeats; 17 for the normal allele). The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro and in vivo assays.

  3. Generation of KCL027 research grade human embryonic stem cell line carrying a mutation in the HTT gene

    PubMed Central

    Jacquet, Laureen; Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Hobbs, Carl; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL027 human embryonic stem cell line was derived from an embryo donated for research that carried an autosomal dominant mutation affecting one allele of the HTT gene encoding huntingtin (43 trinucleotide repeats; 21 for the normal allele). The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro and in vivo assays.

  4. 131I-MIBG Targeting of Neuroblastoma Cells Is Acutely Enhanced by KCl Stimulation through the Calcium/Calmodulin-Dependent Kinase Pathway

    PubMed Central

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

    2013-01-01

    Abstract The efficacy of 131I-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 131I-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 131I-MIBG therapy. PMID:23763646

  5. A Density Model for Multicomponent Liquids Based on the Modified Quasichemical Model: Application to the NaCl-KCl-MgCl2-CaCl2 System

    NASA Astrophysics Data System (ADS)

    Robelin, Christian; Chartrand, Patrice; Eriksson, Gunnar

    2007-12-01

    A theoretical model based on the modified quasichemical model is presented for the density of multicomponent inorganic liquids such as molten salts. By introducing in the Gibbs energy of the liquid phase temperature-dependent molar volume expressions for the pure components and pressure-dependent excess parameters for the binary (and, if necessary, higher-order) interactions, it is possible to reproduce and eventually predict the molar volume and the density of the multicomponent liquid phase using standard interpolation methods. The model is applied to the NaCl-KCl-MgCl2-CaCl2 liquid solutions. No ternary pressure-dependent model parameters were required; the binary pressure-dependent parameters suffice to reproduce satisfactorily the experimental density data available for the NaCl-KCl-MgCl2, NaCl-KCl-CaCl2, NaCl-MgCl2-CaCl2, KCl-MgCl2-CaCl2, and NaCl-KCl-MgCl2-CaCl2 liquids. This is the first of two articles on the density model. In a subsequent article, the model is applied to the NaF-AlF3-CaF2-Al2O3 base electrolyte used for the electroreduction of alumina in Hall-Héroult cells.

  6. 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.

  7. 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.

  8. 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

  9. Activity-dependent cleavage of the K-Cl cotransporter KCC2 mediated by calcium-activated protease calpain.

    PubMed

    Puskarjov, Martin; Ahmad, Faraz; Kaila, Kai; Blaesse, Peter

    2012-08-15

    The K-Cl cotransporter KCC2 plays a crucial role in neuronal chloride regulation. In mature central neurons, KCC2 is responsible for the low intracellular Cl(-) concentration ([Cl(-)](i)) that forms the basis for hyperpolarizing GABA(A) receptor-mediated responses. Fast changes in KCC2 function and expression have been observed under various physiological and pathophysiological conditions. Here, we show that the application of protein synthesis inhibitors cycloheximide and emetine to acute rat hippocampal slices have no effect on total KCC2 protein level and K-Cl cotransporter function. Furthermore, blocking constitutive lysosomal degradation with leupeptin did not induce significant changes in KCC2 protein levels. These findings indicate a low basal turnover rate of the total KCC2 protein pool. In the presence of the glutamate receptor agonist NMDA, the total KCC2 protein level decreased to about 30% within 4 h, and this effect was blocked by calpeptin and MDL-28170, inhibitors of the calcium-activated protease calpain. Interictal-like activity induced by incubation of hippocampal slices in an Mg(2+)-free solution led to a fast reduction in KCC2-mediated Cl(-) transport efficacy in CA1 pyramidal neurons, which was paralleled by a decrease in both total and plasmalemmal KCC2 protein. These effects were blocked by the calpain inhibitor MDL-28170. Taken together, these findings show that calpain activation leads to cleavage of KCC2, thereby modulating GABAergic signaling. PMID:22895718

  10. Measurement and thermodynamic model study on equilibrium solubility in the ternary system KCl-KBr-H2O at 323.15 K

    NASA Astrophysics Data System (ADS)

    Meng, Ling-Zong; Li, Dan; Ma, Cun-Yun; Liu, Kai-Xuan

    2014-12-01

    The solubilities and the refractive indices of the KCl-KBr-H2O system at 323.15 K were studied with the isothermal dissolution method. The phase diagram and refractive index diagram were plotted for this system at 323.15 K. There is only one crystallization field of the solid solution K(Cl, Br). The system belongs to the solid solution type. The refractive indices of the equilibrium solution varies regularly with w(KCl) increasing. The calculated refractive index data are in good agreement with the experimental data. The parameter ΨK, Cl, Br at 323.15 K was fitted using the measured solubility data in this study. The equilibrium constant equation for the equilibrium solids at 323.15 K were obtained using the different Pitzer parameters from the literature or this work with a method using the activity product constant. The calculated solubilities agree well with experimental values.

  11. Monosodium glutamate, disodium inosinate, disodium guanylate, lysine and taurine improve the sensory quality of fermented cooked sausages with 50% and 75% replacement of NaCl with KCl.

    PubMed

    dos Santos, Bibiana Alves; Campagnol, Paulo Cezar Bastianello; Morgano, Marcelo Antônio; Pollonio, Marise Aparecida Rodrigues

    2014-01-01

    Fermented cooked sausages were produced by replacing 50% and 75% of NaCl with KCl and adding monosodium glutamate, disodium inosinate, disodium guanylate, lysine and taurine. The manufacturing process was monitored by pH and water activity measurements. The sodium and potassium contents of the resulting products were measured. The color values (L*, a* and b*), texture profiles and sensory profiles were also examined. Replacing 50% and 75% NaCl with KCl depreciated the sensory quality of the products. The reformulated sausages containing monosodium glutamate combined with lysine, taurine, disodium inosinate and disodium guanylate masked the undesirable sensory attributes associated with the replacement of 50% and 75% NaCl with KCl, allowing the production of fermented cooked sausages with good sensory acceptance and approximately 68% sodium reduction. PMID:24008059

  12. Effect of natural organic matter on the aggregation kinetics of CeO2 nanoparticles in KCl and CaCl2 solutions: measurements and modeling.

    PubMed

    Li, Kungang; Chen, Yongsheng

    2012-03-30

    To characterize the environmental transport and quantify the risk of nanoparticles (NPs), it is important to fundamentally understand the aggregation of NPs and to describe this process quantitatively. This study investigates the aggregation kinetics of CeO(2) NPs in the presence of KCl, CaCl(2) and humic acid (HA) using time-resolved dynamic light scattering. In KCl solutions, regardless of their concentration, HA drastically reduces the aggregation kinetics of CeO(2) NPs. However, the effect of HA was more complicated in CaCl(2) solutions. At low CaCl(2) concentrations, HA inhibited NP aggregation, whereas at high CaCl(2) concentrations, HA promoted aggregation. The critical coagulation concentration (CCC) in KCl in the absence of HA is approximately 36.5mM. In presence of both 1 ppm and 10 ppm HA in KCl solutions, extremely low aggregation kinetics were observed even at very high KCl concentrations (500 mM), implying KCl-CCCs in presence of HA were larger than 500 mM. The CCCs under conditions of no HA, 1 ppm HA and 10 ppm HA in CaCl(2) solutions are approximately 9.5, 8.0 and 12.0mM, respectively. These observations were analyzed in the framework of extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory. Moreover, a kinetic model was used to predict the aggregation kinetics of CeO(2) NPs. The model predictions are in close agreement with experimental observations. To the best of our knowledge, this work is the first to model quantitatively the aggregation of NPs in the presence of natural organic matter. PMID:22285915

  13. A thermodynamic study of electroneutral K-Cl cotransport in pH- and volume-clamped low K sheep erythrocytes with normal and low internal magnesium

    PubMed Central

    1996-01-01

    Swelling-induced human erythrocyte K-Cl cotransport is membrane potential independent and capable of uphill transport. However, a complete thermodynamic analysis of basal and stimulated K-Cl cotransport, at constant cell volume, is missing. This study was performed in low K sheep red blood cells before and after reducing cellular free Mg into the nanomolar range with the divalent cation ionophore A23187 and a chelator, an intervention known to stimulate K- Cl cotransport. The anion exchange inhibitor 4,4'diisothiocyanato- 2,2'disulfonic stilbene was used to clamp intracellular pH and Cl or NO3 concentrations. Cell volume was maintained constant as external and internal pH differed by more than two units. K-Cl cotransport was calculated from the K effluxes and Rb (as K congener) influxes measured in Cl and NO3, at constant internal K and external anions, and variable concentrations of extracellular Rb and internal anions, respectively. The external Rb concentration at which net K-Cl cotransport is zero was defined as flux reversal point which changed with internal pH and hence Cl. Plots of the ratio of external Rb concentrations corresponding to the flux reversal points and the internal K concentration versus the ratio of the internal and external Cl concentrations (i.e., the Donnan ratio of the transported ions) yielded slopes near unity for both control and low internal Mg cells. Thus, basal as well as low internal Mg-stimulated net K-Cl cotransport depends on the electrochemical potential gradient of KCl. PMID:8894982

  14. 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 (ΔEC50 = 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 (ΔEC50 = 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

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

    PubMed

    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 (ΔEC50 = 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 (ΔEC50 = 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

  16. 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.

  17. Accelerated aging of thermally activated batteries which utilize the Li/Si//LiCl-KCl/FeS2 system

    NASA Astrophysics Data System (ADS)

    Searcy, J. Q.; Neiswander, P. A.

    The thermally activated Li(Si)/LiCl-KCl/FeS2 batteries considered are intended for applications which require high reliability and a shelf life of 25 years. In order to determine the feasibility of achieving these requirements, an accelerated aging study was undertaken. The major objective of this work was to identify deleterious chemical reactions that could affect performance and reliability during the 25 year shelf life. The approach used was to accelerate the aging of batteries by storage at elevated temperature, and then to examine and analyze materials from some batteries, while discharging others. The results of the study indicate that the reaction of Li(Si) with water outgassed from the various battery parts is deleterious to shelf life. No other deleterious effects were observed.

  18. 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 μm 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.

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

    PubMed

    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

  20. 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

  1. Electrochemical Behavior of Silicon in the (NaCl-KCl-NaF-SiO2) Molten Salt

    NASA Astrophysics Data System (ADS)

    Cai, Zongying; Li, Yungang; He, Xiaofeng; Liang, Jinglong

    2010-10-01

    The electrochemical behavior of silicon was investigated in a molten salts system including saturation silicon dioxide. Silicon was electrodeposited and MoSi2 was formed on the employed molybdenum working electrode by the diffusivities of silicon and the substrate metals. Transient electrochemical techniques such as cyclic voltammetry and chronoamperometry were used to study the reaction mechanism at the molybdenum electrode. Cyclic voltammograms showed the possibility of electrodeposition of Si at -0.64 V versus Pt reference electrode in a NaCl-KCl-NaF-SiO2 system at 1073 K (800 °C). The electrodeposition of Si is single-step charge-transfer process and the cathode process is irreversible. Chronoamperometry studies indicated that electrocrystallization of Si is controlled by progressive nucleation with a three-dimensional growth mechanism.

  2. Characterization of a cDNA related to K-Cl Cotransporters in the root-knot nematode Meloidogyne incognita.

    PubMed

    Neveu, Cedric; Semblat, Jean-Philippe; Abad, Pierre; Castagnone-Sereno, Philippe

    2002-04-01

    We report the cloning of a full-length cDNA from the plant-parasitic nematode Meloidogyne incognita, which encodes a putative protein of 1082 amino acids showing high similarity with K-Cl cotransporters (KCCs) from the free-living nematode Caenorhabditis elegans (54% identity) and from a number of mammals, including human. Hydropathy analysis indicates typical KCC topology patterns, with a hydrophylic NH2-terminal region, 12 membrane-spanning domains, and a long COOH-terminal hydrophylic region. Alignment of the nematode sequences with eleven KCC sequences from mammals suggests that the nematode proteins may constitute a separated family of KCCs. The M. incognita gene was shown to be expressed in both motile and sedentary stages, which suggests an important function in general physiology of the nematode. By analogy with known proteins, it is hypothesized that this gene is involved in the regulation of cell osmotic pressure to maintain nematode body fluids hyperosmotic to the environment. PMID:12180345

  3. Generation of KCL029 research grade human embryonic stem cell line carrying a mutation in WAS gene

    PubMed Central

    Miere, Cristian; Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL029 human embryonic stem cell line was derived from an embryo donated for research that carried a c.814 T > C mutation in the WAS gene, which is linked to the Wiskott-Aldrich syndrome, a rare, inherited, X-linked, recessive disease characterized by immune dysregulation and microthrombocytopenia. The line is also carrier for a mutation p.N1152H in the gene encoding the cystic fibrosis transmembrane conductance regulator CFTR. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  4. Zirconium behaviour during electrorefining of actinide-zirconium alloy in molten LiCl-KCl on aluminium cathodes

    NASA Astrophysics Data System (ADS)

    Meier, R.; Souček, P.; Malmbeck, R.; Krachler, M.; Rodrigues, A.; Claux, B.; Glatz, J.-P.; Fanghänel, Th.

    2016-04-01

    A pyrochemical electrorefining process for the recovery of actinides from metallic nuclear fuel based on actinide-zirconium alloys (An-Zr) in a molten salt is being investigated. In this process actinides are group-selectively recovered on solid aluminium cathodes as An-Al alloys using a LiCl-KCl eutectic melt at a temperature of 450 °C. In the present study the electrochemical behaviour of zirconium during electrorefining was investigated. The maximum amount of actinides that can be oxidised without anodic co-dissolution of zirconium was determined at a selected constant cathodic current density. The experiment consisted of three steps to assess the different stages of the electrorefining process, each of which employing a fresh aluminium cathode. The results indicate that almost a complete dissolution of the actinides without co-dissolution of zirconium is possible under the applied experimental conditions.

  5. Determination of uranium and rare-earth metals separation coefficients in LiCl KCl melt by electrochemical transient techniques

    NASA Astrophysics Data System (ADS)

    Kuznetsov, S. A.; Hayashi, H.; Minato, K.; Gaune-Escard, M.

    2005-09-01

    The main step in the pyrometallurgical process of spent nuclear fuel recycling is a molten salt electrorefining. The knowledge of separation coefficients of actinides (U, Np, Pu and Am) and rare-earth metals (Y, La, Ce, Nd and Gd) is very important for this step. Usually the separation coefficients are evaluated from the formal standard potentials of metals in melts containing their own ions, values obtained by potentiometric method. Electrochemical experiments were carried out at 723-823 K in order to estimate separation coefficients in LiCl-KCl eutectic melt containing uranium and lanthanum trichlorides. It was shown that for the calculation of uranium and lanthanum separation coefficients it is necessary to determine the voltammetric peak potentials of U(III) and La(III), their concentration in the melt and the kinetic parameters relating to U(III) discharge such as transfer and diffusion coefficients, and standard rate constants of charge transfer.

  6. WNK3 bypasses the tonicity requirement for K-Cl cotransporter activation via a phosphatase-dependent pathway

    PubMed Central

    de los Heros, Paola; Kahle, Kristopher T.; Rinehart, Jesse; Bobadilla, Norma A.; Vázquez, Norma; San Cristobal, Pedro; Mount, David B.; Lifton, Richard P.; Hebert, Steven C.; Gamba, Gerardo

    2006-01-01

    SLC12A cation/Cl− cotransporters are mutated in human disease, are targets of diuretics, and are collectively involved in the regulation of cell volume, neuronal excitability, and blood pressure. This gene family has two major branches with different physiological functions and inverse regulation: K-Cl cotransporters (KCC1–KCC4) mediate cellular Cl− efflux, are inhibited by phosphorylation, and are activated by dephosphorylation; Na-(K)-Cl cotransporters (NCC and NKCC1/2) mediate cellular Cl− influx and are activated by phosphorylation. A single kinase/phosphatase pathway is thought to coordinate the activities of these cotransporters in a given cell; however, the mechanisms involved are as yet unknown. We previously demonstrated that WNK3, a paralog of serine-threonine kinases mutated in hereditary hypertension, is coexpressed with several cation/Cl− cotransporters and regulates their activity. Here, we show that WNK3 completely prevents the cell swelling-induced activation of KCC1–KCC4 in Xenopus oocytes. In contrast, catalytically inactive WNK3 abolishes the cell shrinkage-induced inhibition of KCC1–KCC4, resulting in a >100-fold stimulation of K-Cl cotransport during conditions in which transport is normally inactive. This activation is completely abolished by calyculin A and cyclosporine A, inhibitors of protein phosphatase 1 and 2B, respectively. Wild-type WNK3 activates Na-(K)-Cl cotransporters by increasing their phosphorylation, and catalytically inactive kinase inhibits Na-(K)-Cl cotransporters by decreasing their phosphorylation, such that our data suggest that WNK3 is a crucial component of the kinase/phosphatase signaling pathway that coordinately regulates the Cl− influx and efflux branches of the SLC12A cotransporter family. PMID:16446421

  7. Phosphoregulation of the Na-K-2Cl and K-Cl cotransporters by the WNK kinases.

    PubMed

    Kahle, Kristopher T; Rinehart, Jesse; Lifton, Richard P

    2010-12-01

    Precise regulation of the intracellular concentration of chloride [Cl-]i is necessary for proper cell volume regulation, transepithelial transport, and GABA neurotransmission. The Na-K-2Cl (NKCCs) and K-Cl (KCCs) cotransporters, related SLC12A transporters mediating cellular chloride influx and efflux, respectively, are key determinants of [Cl-]i in numerous cell types, including red blood cells, epithelial cells, and neurons. A common "chloride/volume-sensitive kinase", or related system of kinases, has long been hypothesized to mediate the reciprocal but coordinated phosphoregulation of the NKCCs and the KCCs, but the identity of these kinase(s) has remained unknown. Recent evidence suggests that the WNK (with no lysine = K) serine-threonine kinases directly or indirectly via the downstream Ste20-type kinases SPAK/OSR1, are critical components of this signaling pathway. Hypertonic stress (cell shrinkage), and possibly decreased [Cl-]i, triggers the phosphorylation and activation of specific WNKs, promoting NKCC activation and KCC inhibition via net transporter phosphorylation. Silencing WNK kinase activity can promote NKCC inhibition and KCC activation via net transporter dephosphorylation, revealing a dynamic ability of the WNKs to modulate [Cl-]. This pathway is essential for the defense of cell volume during osmotic perturbation, coordination of epithelial transport, and gating of sensory information in the peripheral system. Commiserate with their importance in serving these critical roles in humans, mutations in WNKs underlie two different Mendelian diseases, pseudohypoaldosteronism type II (an inherited form of salt-sensitive hypertension), and hereditary sensory and autonomic neuropathy type 2. WNKs also regulate ion transport in lower multicellular organisms, including Caenorhabditis elegans, suggesting that their functions are evolutionarily-conserved. An increased understanding of how the WNKs regulate the Na-K-2Cl and K-Cl cotransporters may provide novel opportunities for the selective modulation of these transporters, with ramifications for common human diseases like hypertension, sickle cell disease, neuropathic pain, and epilepsy. PMID:20637866

  8. 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. PMID:26761288

  9. Chemical mechanical planarization of amorphous Ge2Sb2Te5 using KClO4 as oxidizer in acidic slurry

    NASA Astrophysics Data System (ADS)

    He, Aodong; Song, Zhitang; Bo, Liu; Zhong, Min; Weili, Liu; Wang, Liangyong; Yan, Weixia; Lei, Yu; Wu, Guangping

    Amorphous Ge2Sb2Te5 (a-GST) chemical mechanical planarization (CMP) using KClO4 as the oxidizer in an acidicslurry is investigated in the present work. It is shown that the removal rate (RR ) of the a-GST firstly increases and thentends to saturate when the KClO4 concentration is greater than 0.8 wt%, but the static etch rate (SER) linearly increasesfrom low to high KClO4 concentration. To understand the oxidation-reaction capability of Ge, Sb and Te, depth profilesof composition of elements and etch morphology of a-GST immersed in the slurry for some time are measured,respectively. It is found that selective corrosion occurs among Ge, Sb and Te, and an accumulation of Te and loss of Gein a-GST surface region are obvious observed, especially at high KClO4 concentrations. Temperature dependent sheetresistance measurements of all the samples pre- and post-CMP reveal a similar trend, which implies a-GST CMP is ableto keep its characteristic well.

  10. Measurements of the salt-removal of NaCl, KCl and MgCl using a carbon electrode prepared with freezing thawing method in capacitive deionization

    NASA Astrophysics Data System (ADS)

    Endarko, Sari, Intan Permata; Fatimah, Iim

    2016-04-01

    Carbon electrodes prepared with freezing thawing method for desalination purpose has been synthesized and characterized. The carbon electrodes were prepared with an activated carbon (700 - 1400 m2/g) and polyvinyl alcohol (PVA) as a binder using freezing thawing method with 3 and 4 cycles (1 cycle is 12 hours for freezing and 12 hours for thawing). Electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to analyze their electrochemical properties. The main study was to measure the salt-removal of 180 µS/cm NaCl, MgCl and KCl using a capacitive deionization (CDI) unit cell with five pairs of carbon electrodes. The applied potential of 2.0 V and a flow rate of 25 mL/min were used to desalination tests, the result showed that the salt-removal percentage of KCl solution has greater than NaCl and MgCl. The highest value for the salt-removal of NaCl, KCl and MgCl can be achieved for the freezing thawing method with 4 cycles. The salt-removal percentage of KCl was achieved at 64.10% whilst resulted in 54.30 and 54.47 % for NaCl and MgCl, respectively.

  11. 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)

  12. Rauwolscine induces contraction in the dog mesenteric artery precontracted with KCl and endothelin-1: mediation via 5-hydroxytryptamine1-like receptors.

    PubMed

    Shimamoto, Y; Shimamoto, H; Kwan, C Y; Daniel, E E

    1993-01-01

    Rauwolscine, a selective alpha-2 adrenoceptor antagonist, elicited a sustained contraction in the dog mesenteric artery precontracted with 20 mM KCl or 10(-9) M endothelin-1. Cumulative concentration-response curves to rauwolscine were not shifted by spiperone, propranolol, pindolol, mianserin, ketanserin, prazosin or phenoxybenzamine at the concentration of 10(-6) M. The pA2 values against rauwolscine were 8.34 +/- 0.32 for methysergide, 8.52 +/- 0.22 for methiothepin and 5.84 +/- 0.27 for phentolamine, which were in good agreement with the pA2 values for those antagonists against 5-hydroxytryptamine (5-HT) in the dog mesenteric artery precontracted with 20 mM KCl. Contractile responses to 5-HT after pretreatment with 20 mM KCl were antagonized in an apparently competitive manner by 10(-5) M rauwolscine. In the absence of precontraction, rauwolscine also shifted 5-HT-induced contractions in a parallel manner. These data suggest that rauwolscine is a partial agonist with a lower intrinsic activity than 5-HT and acts at the same 5-HT1-like receptors as 5-HT, most probably 5-HT1D receptors, in the dog mesenteric artery precontracted with KCl. PMID:8093725

  13. Short communication: Effect of storage temperature on the solubility of milk protein concentrate 80 (MPC80) treated with NaCl or KCl.

    PubMed

    Sikand, V; Tong, P S; Walker, J; Wang, T; Rodriguez-Saona, L E

    2016-03-01

    A previous study in our laboratory showed that addition of 150 mM NaCl or KCl into diafiltration water improved the solubility of freshly made milk protein concentrate 80 (MPC80). In the present study, the objectives were (1) to evaluate the solubility of NaCl- or KCl-treated MPC80 samples kept at varying temperatures and then stored for extensive periods at room temperature (21C 1C); and (2) to determine if MPC80 samples stored at different temperatures and protein conformation can be grouped or categorized together. Freshly manufactured MPC80 samples were untreated (control), processed with NaCl, or processed with KCl. One set of sample bags was stored at 4C; second and third sets of bags were kept at 25C and 55C for 1 mo (31d) and then transferred to room temperature (21C 1C) storage conditions for 1 yr (365d). Samples were tested for nitrogen solubility index (NSI) and for protein changes by Fourier-transform infrared (FTIR) spectroscopy. Analysis of variance results for NSI showed 2 significantly different groupings of MPC80 samples. The more soluble group contained samples treated with NaCl or KCl and stored at either 4C or 25C. These samples had mean NSI >97.5%. The less soluble groups contained all control samples, regardless of storage temperature, and NaCl- or KCl-treated samples stored at 55C. These samples had mean NSI from 39.5 to 58%. Within each of these groups (more soluble and less soluble), no significant differences in solubility were detected. Pattern recognition analysis by soft independent modeling of class analogy (SIMCA) was used to assess protein changes during storage by monitoring the amide I and amide II (1,700(-1) to 1,300cm(-1)) regions. Dominant bands were observed at 1,385cm(-1) for control, 1,551cm(-1) for KCl-treated samples, and 1,694cm(-1) for NaCl-treated samples. Moreover, SIMCA clustered the MPC80 samples stored at 4C separately from samples stored at 25C and 55C. This study demonstrates that (1) the addition of NaCl or KCl during MPC80 manufacture reduces the deleterious changes in solubility upon prolonged storage at 4C or 25C, and (2) the solubility of samples stored at 55C is poor irrespective of salt treatment. PMID:26805980

  14. 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.

  15. The role of activator concentration and precipitate formation on optical and dosimetric properties of KCl:Eu2+ storage phosphor detectors

    PubMed Central

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

    2013-01-01

    Purpose: The activator ion (Eu2+ in KCl:Eu2+) 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:Eu2+. Methods: Potassium chloride pellets were fabricated with various amounts of europium dopant (0.01–5.0 mol.% Eu2+). Clinical radiation doses were given with a 6 MV linear accelerator. Radiation doses larger than 100 Gy were given with a 137Cs 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-Vc dipoles and Eu-Vc trimers could explain trends in PSL sensitivity and radiation hardness observations. Conclusions: The concentration of the activator ion (Eu2+) significantly affects radiation detection properties of the storage phosphor KCl:Eu2+. An activator concentration between 0.01 and 0.05 mol.% Eu in KCl:Eu2+ storage phosphor detectors is recommended for linear dose response, good PSL sensitivity, predictable temporal stability, and high reusability for megavoltage radiation detection. PMID:24007173

  16. 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.

  17. The K(+)-Cl(-) Cotransporter KCC2 and Chloride Homeostasis: Potential Therapeutic Target in Acute Central Nervous System Injury.

    PubMed

    Wu, Haijian; Che, Xiaoru; Tang, Junjia; Ma, Feiqiang; Pan, Kun; Zhao, Mingfei; Shao, Anwen; Wu, Qun; Zhang, Jianmin; Hong, Yuan

    2016-05-01

    The K(+)-Cl(-) cotransporter-2 (KCC2) is a well-known member of the electroneutral cation-chloride cotransporters with a restricted expression pattern to neurons. This transmembrane protein mediates the efflux of Cl(-) out of neurons and exerts a critical role in inhibitory γ-aminobutyric acidergic (GABAergic) and glycinergic neurotransmission. Moreover, KCC2 participates in the regulation of various physiological processes of neurons, including cell migration, dendritic outgrowth, spine morphology, and dendritic synaptogenesis. It is important to note that down-regulation of KCC2 is associated with the pathogenesis of multiple neurological diseases, which is of particular relevance to acute central nervous system (CNS) injury. In this review, we aim to survey the pathogenic significance of KCC2 down-regulation under the condition of acute CNS injuries. We propose that further elucidation of the molecular mechanisms regarding KCC2 down-regulation after acute CNS injuries is necessary because of potential promising avenues for prevention and treatment of acute CNS injury. PMID:25941074

  18. Loss of K-Cl co-transporter KCC3 causes deafness, neurodegeneration and reduced seizure threshold

    PubMed Central

    Boettger, Thomas; Rust, Marco B.; Maier, Hannes; Seidenbecher, Thomas; Schweizer, Michaela; Keating, Damien J.; Faulhaber, Jörg; Ehmke, Heimo; Pfeffer, Carsten; Scheel, Olaf; Lemcke, Beate; Horst, Jürgen; Leuwer, Rudolf; Pape, Hans-Christian; Völkl, Harald; Hübner, Christian A.; Jentsch, Thomas J.

    2003-01-01

    K-Cl co-transporters are encoded by four homologous genes and may have roles in transepithelial transport and in the regulation of cell volume and cytoplasmic chloride. KCC3, an isoform mutated in the human Anderman syndrome, is expressed in brain, epithelia and other tissues. To investigate the physiological functions of KCC3, we disrupted its gene in mice. This severely impaired cell volume regulation as assessed in renal tubules and neurons, and moderately raised intraneuronal Cl– concentration. Kcc3–/– mice showed severe motor abnormalities correlating with a progressive neurodegeneration in the peripheral and CNS. Although no spontaneous seizures were observed, Kcc3–/– mice displayed reduced seizure threshold and spike-wave complexes on electrocorticograms. These resembled EEG abnormalities in patients with Anderman syndrome. Kcc3–/– mice also displayed arterial hypertension and a slowly progressive deafness. KCC3 was expressed in many, but not all cells of the inner ear K+ recycling pathway. These cells slowly degenerated, as did sensory hair cells. The present mouse model has revealed important cellular and systemic functions of KCC3 and is highly relevant for Anderman syndrome. PMID:14532115

  19. A Molecular Dynamics Simulation of the Transport Properties of Molten (La1/3, K)Cl

    NASA Astrophysics Data System (ADS)

    Matsumiya, Masahiko; Seo, Koichi

    2005-03-01

    Molecular dynamics simulations of molten (La1/3, K)Cl at 1123 K have been performed in order to investigate the correlation between simulated dynamical properties such as the self-exchange velocity (ν), the self-diffusion coefficient (D) and the electrical conductivity (κ) and the corresponding experimental values. The simulated results revealed that v and D of potassium decrease with increasing mole fraction of lanthanum, as expected from the experimental internal cation mobilities, b. The decrease of bK, νK and DK is ascribed to the tranquilization effect by La3+, which strongly interacts with Cl-. In contrast, bLa, νLa, and DLa increase with increasing concentration of La3+. The distorted linkage of the network structure of [LaCl6]3- units was disconnected with increasing the concentration of the alkali chloride. This might be attributed to the stronger association of La3+ with Cl- due to the enhanced charge asymmetry of the two cations neighboring Cl-. The sequence of the calculated v's, D's, and κ's is consistent with those of the referred experimental results.

  20. A Glial K/Cl Transporter Controls Neuronal Receptive Ending Shape by Chloride Inhibition of an rGC.

    PubMed

    Singhvi, Aakanksha; Liu, Bingqian; Friedman, Christine J; Fong, Jennifer; Lu, Yun; Huang, Xin-Yun; Shaham, Shai

    2016-05-01

    Neurons receive input from the outside world or from other neurons through neuronal receptive endings (NREs). Glia envelop NREs to create specialized microenvironments; however, glial functions at these sites are poorly understood. Here, we report a molecular mechanism by which glia control NRE shape and associated animal behavior. The C. elegans AMsh glial cell ensheathes the NREs of 12 neurons, including the thermosensory neuron AFD. KCC-3, a K/Cl transporter, localizes specifically to a glial microdomain surrounding AFD receptive ending microvilli, where it regulates K(+) and Cl(-) levels. We find that Cl(-) ions function as direct inhibitors of an NRE-localized receptor-guanylyl-cyclase, GCY-8, which synthesizes cyclic guanosine monophosphate (cGMP). High cGMP mediates the effects of glial KCC-3 on AFD shape by antagonizing the actin regulator WSP-1/NWASP. Components of this pathway are broadly expressed throughout the nervous system, suggesting that ionic regulation of the NRE microenvironment may be a conserved mechanism by which glia control neuron shape and function. PMID:27062922

  1. Compaction of TiH sub 1. 65 /KClO sub 4 pyrotechnic powder during confined burn

    SciTech Connect

    Hingorani-Norenberg, S.L. ); Razani, A.; Shahinpoor, M. . Dept. of Mechanical Engineering)

    1990-01-01

    The burning behavior of titanium subhydride potassium perchlorate (TiH{sub 1.65}/KClO{sub 4}) is currently under investigation. The research is presently aimed at studying the dynamic compaction of the material as a confined cylindrical charge of the pyrotechnic burns. Flash radiography equipment, optical fibers, and piezoelectric pressure transducers are used to study this phenomenon. The length to diameter ratio of the test charge is thirty and it is pressed in increments, which have a length to diameter ratio of one, into a cylindrical fixture consisting of an epoxy liner in a stainless steel housing. The housing has a series of radial holes to allow optical monitoring, through the transparent liner, of the ignition-front. Lead disks, placed between increments of powder, serve as x-ray tracers. Three 300 kilovolt x-ray heads are pulsed during each experiment, providing information regarding the state of compaction of the powder at three different times during the burn. Fiber optics are used to monitor the location of the ignition front. Pressure transducers monitor the pressure history inside the closed bomb. Tests have been performed with the powder at different initial densities and the data indicate that a significant amount of compaction occurs as the charge burns. 7 refs., 6 figs.

  2. 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.

  3. An experimental study of the burn rate of TiH/sub 1. 65//KClO/sub 4/ pyrotechnic under confinement

    SciTech Connect

    Hingorani-Norenberg, S.L.R.

    1988-11-01

    Titanium subhydride potassium perchlorate is a pyrotechnic powder used extensively in valve actuators. The linear burn rate behavior of this material is of interest in the design of these actuators. In this study, the variation of the burn rate of TiH/sub 1.65//KClO/sub 4/ with bulk density in a zero-free-volume closed bomb is investigated. The data collected indicate that the burn rate of TiH/sub 1.65//KClO/sub 4/ increases with increasing bulk density to a maximum of approximately 700 m/s near 70% of the theoretical maximum density (TMD). Any additional increase in density appears to decrease the burn rate. This variation of burn rate with bulk density and the results of gas permeability measurements are discussed in terms of conductive and convective burning. 44 refs., 18 figs.

  4. 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 11μgL(-1) CuSO4. IC25 values, using dry weight as the endpoint, were 228mgL(-1) NaCl, 356mgL(-1) KCl and 5μgL(-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

  5. Temperature Dependence of Behavior of Interface Between Molten Sn and LiCl-KCl Eutectic Melt Due to Rising Gas Bubble

    NASA Astrophysics Data System (ADS)

    Natsui, Shungo; Nashimoto, Ryota; Takai, Hifumi; Kumagai, Takehiko; Kikuchi, Tatsuya; Suzuki, Ryosuke O.

    2016-02-01

    The behavior of the interface between molten Sn and the LiCl-KCl eutectic melt system was observed directly. We found that the transient behavior of the interface exhibits considerable temperature dependence through a change in its physical properties. The "metal film" generated in the upper molten salt phase significantly influences the shape of the interface. Although the lifetime of the metal film depends on the gas flow rate, it is not affected by the buoyancy if the interfacial tension is dominant.

  6. Measurement of the impedance of aqueous solutions of KCl: An analysis using an extension of the Poisson-Nernst-Planck model

    NASA Astrophysics Data System (ADS)

    Duarte, A. R.; Batalioto, F.; Barbero, G.; Figueiredo Neto, A. M.

    2014-07-01

    We investigate the frequency dependence of the real and imaginary parts of the electric impedance of a cell with titanium electrodes, filled with aqueous solution of KCl in different concentrations. Our experimental data are interpreted by means of an extension of the Poisson-Nernst-Planck model, assuming that the electrodes are not blocking and well described by Ohmic boundary conditions, and that two groups of ions are responsible for the electric conduction. One group is due to the dissociation of KCl in water (majority carriers), the other to the impurities dissolved in water or present in KCl (minority carriers), whose bulk density is very small with respect to first group. The agreement between the experimental data and the theoretical predictions is good, taking into account the small number of free parameters entering in the model. In particular, the diffusion coefficient for the potassium and chloride ions well comparer with those reported in literature. According to our analysis, the role of the carriers related to the impurities present in the solution play a fundamental role in the fit of the experimental data in the low frequency region. The presented model where two groups of ions are present, with the assumption of equal mobilities for positive and negative charges in a group, is motivated by the experimental evidence that in aqueous solution of KCl, K+, and Cl- have approximately the same mobilities. Since the PNP model for an electrolytic solution of the case considered by us predicts an electric response similar to that of an electrolytic solution where the positive and negative ions have different mobility, a comparison with the results reported recently by Macdonald is presented [J. R. Macdonald, Electrochim. Acta, 123, 535 (2014)]. Alternative interpretation of our experimental results related to the assumption of non-blocking electrodes is also discussed.

  7. Generation of KCL021 research grade human embryonic stem cell line carrying a ΔF508 mutation in the CFTR gene

    PubMed Central

    Miere, Cristian; Hewitson, Heema; Wood, Victoria; Kadeva, Neli; Cornwell, Glenda; Codognotto, Stefano; Stephenson, Emma; Ilic, Dusko

    2016-01-01

    The KCL021 human embryonic stem cell line was derived from an embryo donated for research that carried a ΔF508 mutation affecting the CFTR gene encoding the cystic fibrosis transmembrane conductance regulator. The ICM was isolated using laser microsurgery and plated on γ-irradiated human foreskin fibroblasts. Both the derivation and cell line propagation were performed in an animal product-free environment. Pluripotent state and differentiation potential were confirmed by in vitro assays.

  8. 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.

  9. Interplay between structure and transport properties of molten salt mixtures of ZnCl2-NaCl-KCl: A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Manga, Venkateswara Rao; Swinteck, Nichlas; Bringuier, Stefan; Lucas, Pierre; Deymier, Pierre; Muralidharan, Krishna

    2016-03-01

    Molten mixtures of network-forming covalently bonded ZnCl2 and network-modifying ionically bonded NaCl and KCl salts are investigated as high-temperature heat transfer fluids for concentrating solar power plants. Specifically, using molecular dynamics simulations, the interplay between the extent of the network structure, composition, and the transport properties (viscosity, thermal conductivity, and diffusion) of ZnCl2-NaCl-KCl molten salts is characterized. The Stokes-Einstein/Eyring relationship is found to break down in these network-forming liquids at high concentrations of ZnCl2 (>63 mol. %), while the Eyring relationship is seen with increasing KCl concentration. Further, the network modification due to the addition of K ions leads to formation of non-bridging terminal Cl ions, which in turn lead to a positive temperature dependence of thermal conductivity in these melts. This new understanding of transport in these ternary liquids enables the identification of appropriate concentrations of the network formers and network modifiers to design heat transfer fluids with desired transport properties for concentrating solar power plants.

  10. Interplay between structure and transport properties of molten salt mixtures of ZnCl2-NaCl-KCl: A molecular dynamics study.

    PubMed

    Manga, Venkateswara Rao; Swinteck, Nichlas; Bringuier, Stefan; Lucas, Pierre; Deymier, Pierre; Muralidharan, Krishna

    2016-03-01

    Molten mixtures of network-forming covalently bonded ZnCl2 and network-modifying ionically bonded NaCl and KCl salts are investigated as high-temperature heat transfer fluids for concentrating solar power plants. Specifically, using molecular dynamics simulations, the interplay between the extent of the network structure, composition, and the transport properties (viscosity, thermal conductivity, and diffusion) of ZnCl2-NaCl-KCl molten salts is characterized. The Stokes-Einstein/Eyring relationship is found to break down in these network-forming liquids at high concentrations of ZnCl2 (>63 mol. %), while the Eyring relationship is seen with increasing KCl concentration. Further, the network modification due to the addition of K ions leads to formation of non-bridging terminal Cl ions, which in turn lead to a positive temperature dependence of thermal conductivity in these melts. This new understanding of transport in these ternary liquids enables the identification of appropriate concentrations of the network formers and network modifiers to design heat transfer fluids with desired transport properties for concentrating solar power plants. PMID:26957165

  11. Differences in the large extracellular loop between the K(+)-Cl(-) cotransporters KCC2 and KCC4.

    PubMed

    Hartmann, Anna-Maria; Wenz, Meike; Mercado, Adriana; Störger, Christof; Mount, David B; Friauf, Eckhard; Nothwang, Hans Gerd

    2010-07-30

    K(+)Cl(-) cotransporters (KCCs) play fundamental physiological roles in processes such as inhibitory neurotransmission and cell volume regulation. Mammalian genomes encode four distinct KCC paralogs, which share basic transport characteristics but differ significantly in ion affinity, pharmacology, and relative sensitivity to cell volume. Studies to identify divergence in functional characteristics have thus far focused on the cytoplasmic termini. Here, we investigated sequence requirements of the large extracellular loop (LEL) for function in KCC2 and KCC4. Mutation of all four evolutionarily conserved cysteines abolished KCC2 transport activity. This behavior differs from that of its closest relative, KCC4, which is insensitive to this mutation. Chimeras supported the differences in the LEL of the two cotransporters, because swapping wild-type LEL resulted in functional KCC2 but rendered KCC4 inactive. Insertion of the quadruple cysteine substitution mutant of the KCC4 loop, which was functional in the parental isoform, abolished transport activity in KCC2. Dose-response curves of wild-type and chimeric KCCs revealed that the LEL contributes to the different sensitivity to loop diuretics; a KCC2 chimera containing the KCC4 LEL displayed an IC(50) of 396.5 mum for furosemide, which was closer to KCC4 (548.8 mum) than to KCC2 (184.4 mum). Cell surface labeling and immunocytochemistry indicated that mutations do not affect trafficking to the plasma membrane. Taken together, our results show a dramatic and unexpected difference in the sequence requirements of the LEL between the closely related KCC2 and KCC4. Furthermore, they demonstrate that evolutionarily highly conserved amino acids can have different functions within KCC members. PMID:20516068

  12. Automated Potentiometric Titrations in KCl/Water-Saturated Octanol: Method for Quantifying Factors Influencing Ion-Pair Partitioning

    PubMed Central

    2009-01-01

    The knowledge base of factors influencing ion pair partitioning is very sparse, primarily because of the difficulty in determining accurate log PI values of desirable low molecular weight (MW) reference compounds. We have developed a potentiometric titration procedure in KCl/water-saturated octanol that provides a link to log PI through the thermodynamic cycle of ionization and partitioning. These titrations have the advantage of being independent of the magnitude of log P, while maintaining a reproducibility of a few hundredths of a log P in the calculated difference between log P neutral and log P ion pair (diff (log PN − I)). Simple model compounds can be used. The titration procedure is described in detail, along with a program for calculating pKa′′ values incorporating the ionization of water in octanol. Hydrogen bonding and steric factors have a greater influence on ion pairs than they do on neutral species, yet these factors are missing from current programs used to calculate log PI and log D. In contrast to the common assumption that diff (log PN − I) is the same for all amines, they can actually vary more than 3 log units, as in our examples. A major factor affecting log PI is the ability of water and the counterion to approach the charge center. Bulky substituents near the charge center have a negative influence on log PI. On the other hand, hydrogen bonding groups near the charge center have the opposite effect by lowering the free energy of the ion pair. The use of this titration method to determine substituent ion pair stabilization values (IPS) should bring about more accurate log D calculations and encourage species-specific QSAR involving log DN and log DI. This work also brings attention to the fascinating world of nature’s highly stabilized ion pairs. PMID:19265385

  13. Thermal-gradient migration of brine inclusions in salt crystals. [Synthetic single crystals of NaCl and KCl

    SciTech Connect

    Yagnik, S.K.

    1982-09-01

    It has been proposed that high-level nuclear waste be disposed in a geologic repository. Natural-salt deposits, which are being considered for this purpose, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive-decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms which is undesirable. In this work, thermal gradient migration of both all-liquid and gas-liquid inclusions was experimentally studied in synthetic single crystals of NaCl and KCl using a hot-stage attachment to an optical microscope which was capable of imposing temperature gradients and axial compressive loads on the crystals. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is non-linear.At high axial loads, however, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, three different gas phases (helium, air and argon) were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large angle grain boundaries was observed. 35 figures, 3 tables.

  14. 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.

  15. Uranium isotopic composition and uranium concentration in special reference material SRM A (uranium in KCl/LiCl salt matrix)

    SciTech Connect

    Graczyk, D.G.; Essling, A.M.; Sabau, C.S.; Smith, F.P.; Bowers, D.L.; Ackerman, J.P.

    1997-07-01

    To help assure that analysis data of known quality will be produced in support of demonstration programs at the Fuel Conditioning Facility at Argonne National Laboratory-West (Idaho Falls, ID), a special reference material has been prepared and characterized. Designated SRM A, the material consists of individual units of LiCl/KCl eutectic salt containing a nominal concentration of 2.5 wt. % enriched uranium. Analyses were performed at Argonne National Laboratory-East (Argonne, IL) to determine the uniformity of the material and to establish reference values for the uranium concentration and uranium isotopic composition. Ten units from a batch of approximately 190 units were analyzed by the mass spectrometric isotope dilution technique to determine their uranium concentration. These measurements provided a mean value of 2.5058 {+-} 0.0052 wt. % U, where the uncertainty includes estimated limits to both random and systematic errors that might have affected the measurements. Evidence was found of a small, apparently random, non-uniformity in uranium content of the individual SRM A units, which exhibits a standard deviation of 0.078% of the mean uranium concentration. Isotopic analysis of the uranium from three units, by means of thermal ionization mass spectrometry with a special, internal-standard procedure, indicated that the uranium isotopy is uniform among the pellets with a composition corresponding to 0.1115 {+-} 0.0006 wt. % {sup 234}U, 19.8336 {+-} 0.0059 wt. % {sup 235}U, 0.1337 {+-} 0.0006 wt. % {sup 236}U, and 79.9171 {+-} 0.0057 wt. % {sup 238}U.

  16. a Modified Denitrifying Bacteria Method for Dual Stable Isotopic Analysis of of Soil Nitrate in Kcl Extracts: Identification of Bioindicators of Nitrogen Deposition Along a Gradient in the Sonoran Desert

    NASA Astrophysics Data System (ADS)

    Bell, M. D.; Sickman, J. O.; Allen, E. B.

    2011-12-01

    Previous studies performing dual isotopic analysis of nitrate in KCl soil extracts using denitrifying bacteria have not incorporated alterations in the method to compensate for the increased N2O blank produced when the bacteria are exposed to KCl in solution. When 1M KCl is used as a blank, the amount of N2O released from the concentrated bacteria solution is more than four times as high as when using a DI water blank. The excess N2O produced is not an artifact of nitrate impurity in the KCl, although the blank increases with the molarity of KCl up to 1M. The introduction of N2O gas is significant enough to alter the values of IAEA USGS standards (3 μg in 3ml KCl) which in turn results in an inaccurate regression for unknown samples. We reduced the size of the KCl blank and its effect on the standards by adding 3ml of KCl to the bacteria solution prior to purging the sample with He gas. This removes the N2O gas which is released by the bacteria when they initially come in contact with the KCl, and allows for standards to be calibrated to a precision of ± 0.1 % δ15N and ± 0.2 % δ18O. Using this new method, we measured δ15N and δ18O of nitrate in 1M KCl soil extracts taken from surface soil (5cm cores) along a nitrogen deposition gradient spanning the Coachella Valley in the western Sonoran Desert during the summer. Early germinating winter annual plant species (Schismus barbatus, Chaenactic fremontii, and Malacothrix glabrata) were collected as seedlings early in the growing season and again in late spring before senescence. Leaves from the dominant shrub, Larrea tridentata, were also collected from each site. Soil nitrogen from sites on the eastern edge of the valley had δ18O values between +30 and +41%, indicating an influence of atmospheric nitrate in plant available nitrate. There was an inverse correlation (r2=0.907) between soil δ18O and the δ15N of the C.fremontii leaf tissue, which suggests that in areas of high N deposition, some seedlings are able to take up excess nitrogen deposited to the soil surface in the summer. Leaf tissue from L. tridentata had a similar relationship with calculated summer atmospheric nitrogen deposition. These results indicate anthropogenic nitrate is only evident in the soils in areas of high deposition and that isotopic composition of the leaf tissue of some widespread species may be able to be used as a bioindicator of deposition.

  17. Acute Aerobic Swimming Exercise Induces Distinct Effects in the Contractile Reactivity of Rat Ileum to KCl and Carbachol.

    PubMed

    Araujo, Layanne C da Cunha; de Souza, Iara L L; Vasconcelos, Luiz H C; Brito, Aline de Freitas; Queiroga, Fernando R; Silva, Alexandre S; da Silva, Patrícia M; Cavalcante, Fabiana de Andrade; da Silva, Bagnólia A

    2016-01-01

    Aerobic exercise promotes short-term physiological changes in the intestinal smooth muscle associated to the ischemia-reperfusion process; however, few studies have demonstrated its effect on the intestinal contractile function. Thus, this work describes our observations regarding the influence of acute aerobic swimming exercise in the contractile reactivity, oxidative stress, and morphology of rat ileum. Wistar rats were divided into sedentary (SED) and acutely exercised (EX-AC) groups. Animals were acclimated by 10, 10, and 30 min of swimming exercise in intercalated days 1 week before exercise. Then they were submitted to forced swimming for 1 h with a metal of 3% of their body weight attached to their body. Animals were euthanized immediately after the exercise section and the ileum was suspended in organ baths for monitoring isotonic contractions. The analysis of lipid peroxidation was performed in order to determinate the malondialdehyde (MDA) levels as a marker of oxidative stress, and intestinal smooth muscle morphology by histological staining. Cumulative concentration-response curves to KCl were altered in the EX-AC with an increase in both its efficacy and potency (E max = 153.2 ± 2.8%, EC 50 = 1.3 ± 0.1 × 10(-2) M) compared to the SED group (E max = 100%, EC 50 = 1.8 ± 0.1 × 10(-2) M). Interestingly, carbachol had its efficacy and potency reduced in the EX-AC (E max = 67.1 ± 1.4%, EC 50 = 9.8 ± 1.4 × 10(-7) M) compared to the SED group (E max = 100%, EC 50 = 2.0 ± 0.2 × 10(-7) M). The exercise did not alter the MDA levels in the ileum (5.4 ± 0.6 μ mol/mL) in the EX-AC compared to the SED group (8.4 ± 1.7 μ mol/mL). Moreover, neither the circular nor the longitudinal smooth muscle layers thickness were modified by the exercise (66.2 ± 6.0 and 40.2 ± 2.6 μm, respectively), compared to the SED group (61.6 ± 6.4 and 34.8 ± 3.7 μm, respectively). Therefore, the ileum sensitivity to contractile agents is differentially altered by the acute aerobic swimming exercise, without affecting the oxidative stress and the morphology of ileum smooth muscle. PMID:27047389

  18. Structure transition in myosin association with the change of concentration: solubility equilibrium under specified KCl and pH condition.

    PubMed

    Tsunashima, Yoshisuke; Akutagawa, Tohru

    2004-10-15

    We observed, for the first time, the elementary process for the ordered self-assembly formation of myosin in solution. It was realized exclusively under the specific condition of 200 mM KCl, 5 mM phosphate buffer, pH 7.08, at 15-20 degrees C, which is called the transition-generating condition (TGC). Described more in detail: pure myosin extracted from rabbit skeletal muscle exhibited the structural transition in its association form only when the myosin concentration c was changed under TGC. The myosin solubility was saturated in both edges of the total myosin concentration c > 10.0 mg/mL (solubility region II) and c < or = 0.25 mg/mL (solubility region I). In the intermediate region, the association structure of myosin changed stepwise with decreasing c. The steps were classified into four regions: region I (c < or = 0.25 mg/mL), II (0.25 < or = c < or = 0.50 mg/mL), III (0.50 < or = c < or = 5.0 mg/mL), and IV (c > 5.0 mg/mL). In each region except II, the plot of the relative soluble myosin concentration c(aq)/c against c(-1) gave a straight line of different slopes, certifying that myosin constructs self-assemblies by the closed association mechanism and that the self-assembly takes dual structures in each region. In region II, a drastic transition occurred in the self-assembled dual structures. Here, a highly associated (insoluble) giant assembly would break into soluble assemblies composed of several myosin molecules. The solubility region I originates a driving force for this structural transition. The basic binding unit of the self-assembly would be a parallel myosin-dimer constructed by the intermolecular axial staggers of 14.3 and 43 nm, as is observed by X-ray diffraction for the thick filament assembly or light meromyosin paracrystals. Myosin could take a single rod-like chain form only in an extremely low concentration region of c < or = c(aq,0) (= 0.053 mg/mL). The association behavior revealed in the present study suggests strongly that the complementary charge cluster and its electrostatic interaction between parallel myosin rods play a crucial role for the ordered self-assembly formation and that the specific electrostatic atmosphere of the solution under TGC is essential to the association mechanism in skeletal muscle myosin, or the thick filament formation of the mammals. PMID:15378484

  19. Acute Aerobic Swimming Exercise Induces Distinct Effects in the Contractile Reactivity of Rat Ileum to KCl and Carbachol

    PubMed Central

    Araujo, Layanne C. da Cunha; de Souza, Iara L. L.; Vasconcelos, Luiz H. C.; Brito, Aline de Freitas; Queiroga, Fernando R.; Silva, Alexandre S.; da Silva, Patrícia M.; Cavalcante, Fabiana de Andrade; da Silva, Bagnólia A.

    2016-01-01

    Aerobic exercise promotes short-term physiological changes in the intestinal smooth muscle associated to the ischemia-reperfusion process; however, few studies have demonstrated its effect on the intestinal contractile function. Thus, this work describes our observations regarding the influence of acute aerobic swimming exercise in the contractile reactivity, oxidative stress, and morphology of rat ileum. Wistar rats were divided into sedentary (SED) and acutely exercised (EX-AC) groups. Animals were acclimated by 10, 10, and 30 min of swimming exercise in intercalated days 1 week before exercise. Then they were submitted to forced swimming for 1 h with a metal of 3% of their body weight attached to their body. Animals were euthanized immediately after the exercise section and the ileum was suspended in organ baths for monitoring isotonic contractions. The analysis of lipid peroxidation was performed in order to determinate the malondialdehyde (MDA) levels as a marker of oxidative stress, and intestinal smooth muscle morphology by histological staining. Cumulative concentration-response curves to KCl were altered in the EX-AC with an increase in both its efficacy and potency (Emax = 153.2 ± 2.8%, EC50 = 1.3 ± 0.1 × 10−2 M) compared to the SED group (Emax = 100%, EC50 = 1.8 ± 0.1 × 10−2 M). Interestingly, carbachol had its efficacy and potency reduced in the EX-AC (Emax = 67.1 ± 1.4%, EC50 = 9.8 ± 1.4 × 10−7 M) compared to the SED group (Emax = 100%, EC50 = 2.0 ± 0.2 × 10−7 M). The exercise did not alter the MDA levels in the ileum (5.4 ± 0.6 μ mol/mL) in the EX-AC compared to the SED group (8.4 ± 1.7 μ mol/mL). Moreover, neither the circular nor the longitudinal smooth muscle layers thickness were modified by the exercise (66.2 ± 6.0 and 40.2 ± 2.6 μm, respectively), compared to the SED group (61.6 ± 6.4 and 34.8 ± 3.7 μm, respectively). Therefore, the ileum sensitivity to contractile agents is differentially altered by the acute aerobic swimming exercise, without affecting the oxidative stress and the morphology of ileum smooth muscle. PMID:27047389

  20. 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.

  1. 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.

  2. A comparison of the effects of various sex steroids on cholecystokinin- and KCl-induced tension in female guinea pig gallbladder strips.

    PubMed

    Kline, Loren; Karpinski, Edward

    2013-05-01

    Estrogen (E) has been shown to have an inhibitory effect on the contractility of gastrointestinal smooth muscle, including the gallbladder. During pregnancy E and progesterone (P) levels are elevated. A biliary stasis may develop during pregnancy that is characterized by an increase in the fasting and residual volumes and by a decrease in emptying capacity. This study investigates the effect of 17β-estradiol (E2), dihydrotestosterone (DHT), P, 17-hydroxyprogesterone (17-P), and a P metabolite, 20α-hydroxyprogesterone (20-P) on contraction in female guinea pig gallbladder strips. DHT, P, 17-P, 20-P, and E2 each induced a concentration-dependent relaxation of cholecystokinin octapeptide (CCK) induced tension. DHT, E2, and P also induced a concentration-dependent relaxation of KCl-induced tension. When the response to E2 was compared to strips from young female guinea pigs with those taken from guinea pigs in late pregnancy, there was no significant difference in the response to either 50 or 100 μM E2; however, 10 μM E2 caused a significant increase (p<0.05) in the amount of relaxation in strips from pregnant guinea pigs. Treatment of the strips from young guinea pigs with PKA inhibitor 14-22 amide myristolated had no significant effect on the E2-induced relaxation. Treatment of the strips with 2-APB, an inhibitor of IP3 induced Ca(2+) release, produced a significant (p<0.001) increase in the amount of E2-induced relaxation when either CCK or KCl were used. Neither KT5823, a PKG inhibitor, nor L-NMMA, a nitric oxide (NO) synthase inhibitor, had a significant effect on the E2-induced relaxation. Bisindolymaleimide IV and chelerythrine Cl(-), PKC blockers, were used in combination with no significant effect on the amount of CCK-induced tension, but significantly (p<0.01) increased the amount of E2-induced relaxation. When either E2 or P were added to the chambers 3 min prior to either CCK or KCl, a significant decrease (p<0.001) in the amount of tension generated was observed. The inhibition of extracellular Ca(2+) entry mediates both P-induced and E2-induced relaxation of CCK- and KCl-induced tension in female guinea pig gallbladder strips. PMID:23399969

  3. Extensive lesions in rat insular cortex significantly disrupt taste sensitivity to NaCl and KCl and slow salt discrimination learning.

    PubMed

    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

  4. 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

  5. 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.

  6. Band structures and charge densities of KCl, NaF, and LiF obtained by the intersecting-spheres model

    NASA Astrophysics Data System (ADS)

    Antoci, S.; Mihich, L.

    1980-01-01

    The self-consistent electronic structures of KCl, NaF, and LiF have been calculated by the intersecting-spheres model and the results were compared with band structures calculated by other methods using the approximation of the exchange potential adopted by us. While for KCl close agreement was found between the augmented-plane-wave non-muffin-tin results by De Cicco and the intersecting-spheres-model (ISM) band structure, in the case of LiF differences of even 2.5 eV were found between conduction bands calculated by the ISM and the corresponding levels determined by linear-combination-of-atomic-orbitals (LCAO) methods. This disagreement seems to be imputable to a lack of convergence occurring in the LCAO calculations. The Fourier components of the charge densities (scattering factors) were determined using the Kohn-Sham-Gáspár form of the exchange potential. The agreement of the calculated scattering factors with experiment is not much worse than that obtained by Hartree-Fock calculations.

  7. 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.

  8. The effect of mixed HCl-KCl competitive adsorbate on Pt adsorption and catalytic properties of Pt-Sn/Al2O3 catalysts in propane dehydrogenation

    NASA Astrophysics Data System (ADS)

    Zangeneh, Farnaz Tahriri; Taeb, Abbas; Gholivand, Khodayar; Sahebdelfar, Saeed

    2015-12-01

    The effect of competitive adsorbate concentration and combination on the adsorption of H2PtCl6 onto γ-Al2O3 in the preparation and performance of PtSnK/γ-Al2O3 catalyst for propane dehydrogenation was investigated. The catalysts were prepared by sequential impregnation of Sn and Pt precursors. The effect of competitor concentration on Pt adsorption was studied by using hydrochloric acid (0.1-0.3 M) and the effect of pH was studied by using KCl/HCl mixtures at constant (0.1 M) total chloride ion concentration. The catalysts were characterized by nitrogen adsorption/desorption, XRD, XRF, SEM and CO chemisorption. The catalytic performance tests were carried out in a fixed-bed quartz reactor under kinetic controlled condition for proper catalyst screening. It was found that the corrosive competitor HCl could be partially substituted with KCl without appreciable impact on catalyst performance with the advantage of lower acid attack on the support and reduced leaching of the deposited tin. A model based on initial concentration and uptake of the adsorbates was developed to obtain the adsorption parameters. Values of 890 μmol/g and 600 lit/mol were obtained for adsorption site concentration of the tin-impregnated support and equilibrium constant for Pt adsorption, respectively, for HCl concentration range of 0.1-0.3 M.

  9. 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.

  10. 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.

  11. Flexible electromagnetic wave sensor operating at GHz frequencies for instantaneous concentration measurements of NaCl, KCl, MnCl2 and CuCl solutions

    NASA Astrophysics Data System (ADS)

    Korostynska, O.; Ortoneda-Pedrola, M.; Mason, A.; Al-Shamma'a, A. I.

    2014-06-01

    A novel electromagnetic wave sensor operating at GHz frequencies for real-time chlorides concentration analysis is reported. The sensor response to deionized water, NaCl, KCl, MnCl2 and CuCl solutions at various concentrations was tested. The sensing element, in the form of a silver pattern antenna that emits an electromagnetic field, was printed on a polyimide flexible laminate substrate to form a sensor to suit a broad range of applications, where a sensor could be placed in water reservoirs or fluid-carrying pipes for continuous analysis. The developed system confirmed the viability of using microwaves for real-time chloride solutions monitoring as the reflected signals represented by S11 parameters were unique with clearly observed shifts in the resonant frequencies and amplitude changes when placed in direct contact with 20 µl of each solution. This paper was an invited article at the Sensors and Applications XVII conference.

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

    NASA Astrophysics Data System (ADS)

    Souček, 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.

  13. 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.

  14. Influence of partial replacement of NaCl with KCl and CaCl(2) on texture and color of dry fermented sausages.

    PubMed

    Gimeno, O; Astiasarán, I; Bello, J

    1999-03-01

    A Spanish type of dry fermented sausage, Chorizo de Pamplona, was manufactured with a mixture of (2.29%) different salts (NaCl, KCl, and CaCl(2)) with an equivalent ionic strength to that of the control manufactured with 2.6% NaCl. The use of this salt mixture affected the texture profile analysis (TPA), giving rise to a significant reduction in hardness, cohesiveness, gumminess and chewiness. Instrumental color values showed higher b (yellowness) and L (lightness) values. Sensory texture and color intensity yielded lower scores, but they were classified as acceptable. Principal component analysis was carried out with the instrumental measures. The two principal components explained 76.9% of the variance. Modified and control samples were separated by the first component, which explained 57.1% of the variance and was defined basically by texture parameters. PMID:10552384

  15. Behaviour of F and F-z centres under thermal stimulation in KCl : Eu2+ irradiated with ionizing and UV radiation

    NASA Astrophysics Data System (ADS)

    Chernov, V.; Piters, T. M.; Barboza-Flores, M.

    2003-01-01

    The optical absorption (OA) of F and F-z centres in beta- and UV-irradiated KCl:Eu2+ have been studied. The spectra measured at room temperature and during the subsequent heatings up to 600 K, were analyzed by a deconvolution procedure. The OA bands of the F and F-z centres are well described respectively by asymmetric and symmetric gaussians with parameters that are linearly dependent on the temperature. The thermal stability of the F-z centres correlates with the low-temperature thermostimulated luminescence (TL) peaks. The stability of the F centres is determined at least by two processes. Part of the F centres is destroyed together with the F-z centres. The remaining ones are destroyed during further heating up to 470 K, correlating with the TL peak at 425 K (at heating rate of 0.1 K/s).

  16. 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.

  17. Localization of the K(+)-Cl(-) cotransporter, KCC3, in the central and peripheral nervous systems: expression in the choroid plexus, large neurons and white matter tracts.

    PubMed

    Pearson, M M; Lu, J; Mount, D B; Delpire, E

    2001-01-01

    Na(+)-independent K(+)-Cl(-) cotransporters function in the regulation of cell volume, control of CNS excitability and epithelial ion transport. Several K(+)-Cl(-) cotransporter isoforms are expressed in the nervous system, and KCC3 in particular is expressed at significant levels in both the brain and spinal cord. The cellular localization of this transporter has, however, not been determined. In this study, we generated a polyclonal antibody against the KCC3 cotransporter in order to characterize and localize this protein in the brain. Western blot analysis of mouse kidney and brain demonstrated KCC3 proteins of different size, 150 and 170kDa, respectively; this disparity remained after deglycosylation. Northern blot confirmed the presence of two distinct forms of KCC3, KCC3a and KCC3b, generated by the inclusion of different first coding exons. KCC3a predominates in the brain, whereas KCC3b is more abundant in the kidney. Western blots with membrane protein from dissected mouse brain revealed abundant expression in all brain regions examined: the cerebral cortex, hippocampus, diencephalon, brainstem and cerebellum. The spinal cord showed the highest levels of KCC3 expression, whereas peripheral nerves did not contain immunoreactive KCC3 protein. Western blot analysis of whole brain from rats of various ages indicated increasing expression in the postnatal period, concurrent with CNS maturation and myelination. Immunofluorescence studies demonstrated strong signal in myelinated tracts of the spinal cord, consistent with individual myelin sheaths. Brain sections also showed white matter enhancement, but also cellular signal consistent with pyramidal neurons and Purkinje cells. The base of the choroid plexus epithelium was also strongly labeled. These data demonstrate the specificity and diversity of KCC3 expression in the mouse CNS. PMID:11246162

  18. Seizure sensitivity is ameliorated by targeted expression of K+-Cl- cotransporter function in the mushroom body of the Drosophila brain.

    PubMed

    Hekmat-Scafe, Daria S; Mercado, Adriana; Fajilan, Adriel A; Lee, Ann W; Hsu, Richard; Mount, David B; Tanouye, Mark A

    2010-01-01

    The kcc(DHS1) allele of kazachoc (kcc) was identified as a seizure-enhancer mutation exacerbating the bang-sensitive (BS) paralytic behavioral phenotypes of several seizure-sensitive Drosophila mutants. On their own, young kcc(DHS1) flies also display seizure-like behavior and demonstrate a reduced threshold for seizures induced by electroconvulsive shock. The product of kcc shows substantial homology to KCC2, the mammalian neuronal K(+)-Cl(-) cotransporter. The kcc(DHS1) allele is a hypomorph, and its seizure-like phenotype reflects reduced expression of the kcc gene. We report here that kcc functions as a K(+)-Cl(-) cotransporter when expressed heterologously in Xenopus laevis oocytes: under hypotonic conditions that induce oocyte swelling, oocytes that express Drosophila kcc display robust ion transport activity observed as a Cl(-)-dependent uptake of the K(+) congener (86)Rb(+). Ectopic, spatially restricted expression of a UAS-kcc(+) transgene was used to determine where cotransporter function is required in order to rescue the kcc(DHS1) BS paralytic phenotype. Interestingly, phenotypic rescue is largely accounted for by targeted, circumscribed expression in the mushroom bodies (MBs) and the ellipsoid body (EB) of the central complex. Intriguingly, we observed that MB induction of kcc(+) functioned as a general seizure suppressor in Drosophila. Drosophila MBs have generated considerable interest especially for their role as the neural substrate for olfactory learning and memory; they have not been previously implicated in seizure susceptibility. We show that kcc(DHS1) seizure sensitivity in MB neurons acts via a weakening of chemical synaptic inhibition by GABAergic transmission and suggest that this is due to disruption of intracellular Cl(-) gradients in MB neurons. PMID:19884312

  19. Electrochemical characterization of an asymmetric nanofiltration membrane with NaCl and KCl solutions: influence of membrane asymmetry on transport parameters.

    PubMed

    Cañas, A; Benavente, J

    2002-02-15

    Electrochemical characterization of a nanofiltration asymmetric membrane was carried out by measuring membrane potential, salt diffusion, and electrical parameters (membrane electrical resistance and capacitance) with the membrane in contact with NaCl and KCl solutions at different concentrations (10(-3)< or =c(M)< or =5 x 10(-2)). From these experiments characteristic parameters such as the effective concentration of charge in the membrane, ionic transport numbers, and salt and ionic permeabilities across the membrane were determined. Membrane electrical resistance and capacitance were obtained from impedance spectroscopy (IS) measurements by using equivalent circuits as models. This technique allows the determination of the electrical contribution associated with each sublayer; then, assuming that the dense sublayer behaves as a plane capacitor, its thickness can be estimated from the capacitance value. The influence of membrane asymmetry on transport parameters have been studied by carrying out measurements for the two opposite external conditions. Results show that membrane asymmetry strongly affects membrane potential, which is attributed to the Donnan exclusion when the solutions in contact with the dense layer have concentrations lower than the membrane fixed charge (X(ef) approximately -0.004 M), but for the reversal experimental condition (high concentration in contact with the membrane dense sublayer) the membrane potential is practically similar to the solution diffusion potential. The comparison of results obtained for both electrolytes agrees with the higher conductivity of KCl solutions. On the other hand, the influence of diffusion layers at the membrane/solution interfaces in salt permeation was also studied by measuring salt diffusion at a given NaCl concentration gradient but at five different solutions stirring rates. PMID:16290419

  20. [Study of the metal precipitation from decontamination leachates of municipal wastes fly ash incinerators].

    PubMed

    Levasseur, B; Blais, J F; Mercier, G

    2005-04-01

    This research work focuses on the development of a new process for the decontamination of municipal wastes incinerators fly ashes. The objective of this study was to evaluate different total and selective precipitation methods for metals removal from ash decontamination leachates. The tested options include 1) use of hydrated lime and caustic soda for selective (pH 5.0) and total (pH 8.5) metal precipitation; 2) addition of different chemicals (H3PO4, Na2S and FeCl3) in a pH range from 6.0 to 9.0. Fly ash decontamination assays using alkaline and acid washing steps were initially performed using optimal conditions previously established. Treated fly ashes respected the standards based on the TCLP leaching test for all studied metals and SPLP. Total metal precipitation tests carried out at pH 8.5 achieve removal yields for all metals > or = 90% using hydrated lime and > or = 83% using caustic soda. Selective precipitation tests alone at pH 5.0 show removal yields > or = 97% for Cr and between 75 and 87% for Al and Pb. Moreover, assays carried out using a stoechiometric addition of Na2S have allowed the separation of Cd (> or = 99%) and Zn (> or = 71%) as metal sulphides (CdS and ZnS). From an economical point of view, the most interesting option seems to be the leachates neutralization at pH 7.0 using Ca(OH)2 combined with the reuse of the treated leachates in the fly ash leaching steps. Metal precipitation cost at pH 7.0 has been estimated to be 22.7 CAN dollars tct-1 using Ca(OH)2, and 26.7 CAN dollars tct-1 using NaOH. PMID:15906494

  1. Alginate-based bipolymeric-nanobioceramic composite matrices for sustained drug release.

    PubMed

    Hasnain, M Saquib; Nayak, Amit Kumar; Singh, Mukul; Tabish, Mohammad; Ansari, Mohammed Tahir; Ara, Tahseen Jahan

    2016-02-01

    Alginate-based bipolymeric-nanobioceramic composite matrices for sustained drug release were developed through incorporation of nano-hydroxyapatite [nHAp] powders within ionotropically-gelled calcium ion-induced alginate-poly (vinyl pyrrolidone) blends polymeric systems. nHAp powders were synthesized by precipitation technique using calcium hydroxide [Ca(OH)2] and orthophosphoric acid [H3PO4] as raw materials. The average particle size of these was synthesized. nHAp powders was found as 19.04nm and used to prepare nHAp-alginate-PVP beads containing DS. These beads exhibited drug entrapment efficiency (%) of 65.82±1.88 to 94.45±3.72% and average bead sizes of 0.98±0.07 to 1.23±0.15mm. These beads were characterized by scanning electron microscopy (SEM) and Fourier transform-infra red (FTIR) spectroscopy analyses. Various nHAp-alginate-PVP beads containing DS exhibited prolonged sustained drug release and followed the Koresmeyer-Peppas model of drug release (R(2)=0.9908-0.9978) with non-Fickian release (anomalous transport) mechanism (n=0.73-0.84) for drug release over 8h. PMID:26608007

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

    NASA Astrophysics Data System (ADS)

    Stanić, Vojislav; Dimitrijević, Suzana; Antonović, Dušan G.; Jokić, Bojan M.; Zec, Slavica P.; Tanasković, Sladjana T.; Raičević, 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.

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

    NASA Astrophysics Data System (ADS)

    Stanić, Vojislav; Radosavljević-Mihajlović, Ana S.; Živković-Radovanović, Vukosava; Nastasijević, Branislav; Marinović-Cincović, Milena; Marković, 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.

  4. Preparation and in vitro investigation of chitosan/nano-hydroxyapatite composite used as bone substitute materials.

    PubMed

    Li, Zhang; Yubao, Li; Aiping, Yang; Xuelin, Peng; Xuejiang, Wang; Xiang, Zhang

    2005-03-01

    Chitosan/nano-hydroxyapatite composites with different weight ratios were prepared through a co-precipitation method using Ca(OH)(2), H(3)PO(4) and chitosan as starting materials. The properties of these composites were characterized by means of TEM, IR, XRD, burn-out test and universal matertial test machine. Additionally, in vitro tests were also conducted to investigate the biodegradability and bioactivity of the composite. The results showed that the HA synthesized here was poorly crystalline carbonated nanometer crystals and dispersed uniformly in chitosan phase and there is no phase-separation between the two phases. Because of the interactions between chitosan and n-HA, the mechanical properties of these composites were improved, and the maximum value of the compressive strength was measured about 120 MPa corresponding to the chitosan/n-HA composite with a weight ratio of 30/70. The specimens made of 30/70 chitosan/n-HA composite exhibit high biodegradability and bioactivity when being immersed in SBF solutions. The composite is appropriate to being used as scaffold materials for bone tissue engineering. (c) Springer Science + Business Media, Inc. PMID:15744612

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

    NASA Astrophysics Data System (ADS)

    Stanić, Vojislav; Janaćković, Djordje; Dimitrijević, Suzana; Tanasković, Sladjana B.; Mitrić, Miodrag; Pavlović, Mirjana S.; Krstić, Aleksandra; Jovanović, Dragoljub; Raičević, 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. Development of monetite-nanosilica bone cement: a preliminary study.

    PubMed

    Zhou, Huan; Luchini, Timothy J F; Agarwal, Anand K; Goel, Vijay K; Bhaduri, Sarit B

    2014-11-01

    In this paper, we reported the results of our efforts in developing DCPA/nanosilica composite orthopedic cement. It is motivated by the significances of DCPA and silicon in bone physiological activities. More specifically, this paper examined the effects of various experimental parameters on the properties of such composite cements. In this work, DCPA cement powders were synthesized using a microwave synthesis technique. Mixing colloidal nanosilica directly with synthesized DCPA cement powders can significantly reduce the washout resistance of DCPA cement. In contrast, a DCPA-nanosilica cement powder prepared by reacting Ca(OH)2 , H3 PO4 and nanosilica together showed good washout resistance. The incorporation of nanosilica in DCPA can improve compressive strength, accelerate cement solidification, and intensify surface bioactivity. In addition, it was observed that by controlling the content of NaHCO3 during cement preparation, the resulting composite cement properties could be modified. Allowing for the development of different setting times, mechanical performance and crystal features. It is suggested that DCPA-nanosilica composite cement can be a potential candidate for bone healing applications. PMID:24652701

  7. The K-Cl cotransporter KCC3 is mutant in a severe peripheral neuropathy associated with agenesis of the corpus callosum.

    PubMed

    Howard, Heidi C; Mount, David B; Rochefort, Daniel; Byun, Nellie; Dupr, Nicolas; Lu, Jianming; Fan, Xuemo; Song, Luyan; Rivire, Jean-Baptiste; Prvost, Claude; Horst, Jrgen; Simonati, Alessandro; Lemcke, Beate; Welch, Rick; England, Roger; Zhan, Frank Q; Mercado, Adriana; Siesser, William B; George, Alfred L; McDonald, Michael P; Bouchard, Jean-Pierre; Mathieu, Jean; Delpire, Eric; Rouleau, Guy A

    2002-11-01

    Peripheral neuropathy associated with agenesis of the corpus callosum (ACCPN) is a severe sensorimotor neuropathy associated with mental retardation, dysmorphic features and complete or partial agenesis of the corpus callosum. ACCPN is transmitted in an autosomal recessive fashion and is found at a high frequency in the province of Quebec, Canada. ACCPN has been previously mapped to chromosome 15q. The gene SLC12A6 (solute carrier family 12, member 6), which encodes the K+-Cl- transporter KCC3 and maps within the ACCPN candidate region, was screened for mutations in individuals with ACCPN. Four distinct protein-truncating mutations were found: two in the French Canadian population and two in non-French Canadian families. The functional consequence of the predominant French Canadian mutation (2436delG, Thr813fsX813) was examined by heterologous expression of wildtype and mutant KCC3 in Xenopus laevis oocytes; the truncated mutant is appropriately glycosylated and expressed at the cellular membrane, where it is non-functional. Mice generated with a targeted deletion of Slc12a6 have a locomotor deficit, peripheral neuropathy and a sensorimotor gating deficit, similar to the human disease. Our findings identify mutations in SLC12A6 as the genetic lesion underlying ACCPN and suggest a critical role for SLC12A6 in the development and maintenance of the nervous system. PMID:12368912

  8. 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.

  9. 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.

  10. Electrochemical characterisation of CaCl2 deficient LiCl-KCl-CaCl2 eutectic melt and electro-deoxidation of solid UO2

    NASA Astrophysics Data System (ADS)

    Sri Maha Vishnu, D.; Sanil, N.; Mohandas, K. S.; Nagarajan, K.

    2016-03-01

    The CaCl2 deficient ternary eutectic melt LiCl-KCl-CaCl2 (50.5: 44.2: 5.3 mol %) was electrochemically characterised by cyclic voltammetry and polarization techniques in the context of its probable use as the electrolyte in the electrochemical reduction of solid UO2 to uranium metal. Tungsten (cathodic polarization) and graphite (anodic polarization) working electrodes were used in these studies carried out in the temperature range 623 K-923 K. The cathodic limit of the melt was observed to be set by the deposition of Ca2+ ions followed by Li+ ions on the tungsten electrode and the anodic limit by oxidation of chloride ions on the graphite electrode (chlorine evolution). The difference between the onset potential of deposition of Ca2+ and Li+ was found to be 0.241 V at a scan rate of 20 mV/s at 623 K and the difference decreased with increase in temperature and vanished at 923 K. Polarization measurements with stainless steel (SS) cathode and graphite anode at 673 K showed the possibility of low-energy reactions occurring on the UO2 electrode in the melt. UO2 pellets were cathodically polarized at 3.9 V for 25 h to test the feasibility of electro-reduction to uranium in the melt. The surface of the pellets was found reduced to U metal.

  11. Thermoluminescence response of new KCl(X)Br(1-X):EuCl3 sintered phosphors exposed to beta and gamma radiation.

    PubMed

    Bernal, R; Cruz-Zaragoza, E; Cruz-Vázquez, C; Burruel-Ibarra, S E; Rivera-Flores, M J; Barboza-Flores, M

    2006-01-01

    Alkali halides crystals have been the subject of intense research for an understanding of their radiation-induced defects and luminescence properties. They exhibit noteworthy thermoluminescence (TL) properties when exposed to ionising radiation. Currently, these materials are grown employing expensive and rather complicated techniques. In this work, the results on the TL properties of new alkali halides phosphors fabricated by a simple and inexpensive procedure are presented. The samples were made by mixing KCl, KBr and EuCl3 salts, and compressing them at a pressure of 3.2 x 10(7) Pa during 3 min, followed by sintering at 700 degrees C during 24 h under air atmosphere. The dosimetric response of the samples showed an increase with radiation dose in the 1.5-20.0 Gy dose range for beta and gamma radiation. The TL glow curves in sintered samples presented significant differences in their peak structures compared with monocrystalline samples, indicating that the nature of the trapping states and the recombination mechanisms may be different. PMID:16702244

  12. Temperature invariance of NaCl solubility in water: inferences from salt-water cluster behavior of NaCl, KCl, and NH4Cl.

    PubMed

    Bharmoria, Pankaj; Gupta, Hariom; Mohandas, V P; Ghosh, Pushpito K; Kumar, Arvind

    2012-09-27

    The growth and stability of salt-water clusters have been experimentally studied in aqueous solutions of NaCl, KCl, and NH(4)Cl from dilute to near-saturation conditions employing dynamic light scattering and zeta potential measurements. In order to examine cluster stability, the changes in the cluster sizes were monitored as a function of temperature. Compared to the other cases, the average size of NaCl-water clusters remained almost constant over the studied temperature range of 20-70 C. Information obtained from the temperature-dependent solution compressibility (determined from speed of sound and density measurements), multinuclear NMR ((1)H, (17)O, (35)Cl NMR), and FTIR were utilized to explain the cluster behavior. Comparison of NMR chemical shifts of saturated salt solutions with solid-state NMR data of pure salts, and evaluation of spectral modifications in the OH stretch region of saturated salt solutions as compared to that of pure water, provided important clues on ion pair-water interactions and water structure in the clusters. The high stability and temperature independence of the cluster sizes in aqueous NaCl shed light on the temperature invariance of its solubility. PMID:22937984

  13. Solubilities of salts in the ternary systems NaCl + CaCl2 + H2O and KCl + CaCl2 + H2O at 75°C

    NASA Astrophysics Data System (ADS)

    Yang, Ji-Min; Liu, Xiao-Lin; Liang, Pei-Pei

    2011-07-01

    The solubility in the NaCl-CaCl2-H2O and KCl-CaCl2-H2O systems were determined at 75°C and the phase diagrams and the diagram of physicochemical property vs composition were plotted. One invariant point, two univariant curves, and two crystallization zones, corresponding to potassium chloride, dihydrate (CaCl2 · 2H2O) showed up in the phase diagrams of the ternary systems. The mixing parameters θM, Ca and ΨM, Ca, Cl (M = Na or K) and equilibrium constant K sp were evaluated in NaCl-CaCl2-H2O and KCl-CaCl2-H2O systems by least-squares optimization procedure, in which the single-salt Pitzer parameters of NaCl, KCl, and CaCl2 β(0), β(1), β(2), and C Φ were directly calculated from the literature. The results obtained were in good agreement with the experimental data.

  14. Rutile solubility in NaF-NaCl-KCl-bearing aqueous fluids at 0.5-2.79 GPa and 250-650 °C

    NASA Astrophysics Data System (ADS)

    Tanis, Elizabeth A.; Simon, Adam; Zhang, Youxue; Chow, Paul; Xiao, Yuming; Hanchar, John M.; Tschauner, Oliver; Shen, Guoyin

    2016-03-01

    The complex nature of trace element mobility in subduction zone environments is thought to be primarily controlled by fluid-rock interactions, episodic behavior of fluids released, mineral assemblages, and element partitioning during phase transformations and mineral breakdown throughout the transition from hydrated basalt to blueschist to eclogite. Quantitative data that constrain the partitioning of trace elements between fluid(s) and mineral(s) are required in order to model trace element mobility during prograde and retrograde metamorphic fluid evolution in subduction environments. The stability of rutile has been proposed to control the mobility of HFSE during subduction, accounting for the observed depletion of Nb and Ta in arc magmas. Recent experimental studies demonstrate that the solubility of rutile in aqueous fluids at temperatures >700 °C and pressures <2 GPa increases by several orders of magnitude relative to pure H2O as the concentrations of ligands (e.g., F and Cl) in the fluid increase. Considering that prograde devolatilization in arcs begins at ∼300 °C, there is a need for quantitative constraints on rutile solubility and the partitioning of HFSE between rutile and aqueous fluid over a wider range of temperature and pressure than is currently available. In this study, new experimental data are presented that quantify the solubility of rutile in aqueous fluids from 0.5 to 2.79 GPa and 250 to 650 °C. Rutile solubility was determined by using synchrotron X-ray fluorescence to measure the concentration of Zr in an aqueous fluid saturated with a Zr-bearing rutile crystal within a hydrothermal diamond anvil cell. At the PT conditions of the experiments, published diffusion data indicate that Zr is effectively immobile (log DZr ∼10-25 m2/s at 650 °C and ∼10-30 m2/s at 250 °C) with diffusion length-scales of <0.2 μm in rutile for our run durations (<10 h). Hence, the Zr/Ti ratio of the starting rutile, which was quantified, does not change during the experiment, and the measured concentration of Zr in the fluid was used to calculate the concentration of Ti (i.e., the solubility of rutile) in the fluid. The salts NaF, NaCl, and KCl were systematically added to the aqueous fluid, and the relative effects of fluid composition, pressure, and temperature on rutile solubility were quantified. The results indicate that fluid composition exerts the greatest control on rutile solubility in aqueous fluid, consistent with previous studies, and that increasing temperature has a positive, albeit less pronounced, effect. The solubility of Zr-rutile in aqueous fluid increases with the addition of halides in the following order: 2 wt% NaF < 30 wt% KCl < 30 wt% NaCl < 3 wt% NaF < (10 wt% NaCl + 2 wt% NaF) < 4 wt% NaF. The solubility of rutile in the fluid increases with the 2nd to 3rd power of the Cl- concentration, and the 3rd to 4th power of the F- concentration. These new data are consistent with observations from field studies of exhumed terranes that indicate that rutile is soluble in complex aqueous fluids, and that fluid composition is the primary control on rutile solubility and HFSE mobility.

  15. Effect of the calcineurin inhibitor FK506 on K+-Cl- cotransporter 2 expression in the mouse hippocampus after kainic acid-induced status epilepticus.

    PubMed

    Shin, Hyun Joo; Jeon, Byeong Tak; Kim, Jungmee; Jeong, Eun Ae; Kim, Myeung Ju; Lee, Dong Hoon; Kim, Hyun Joon; Kang, Sang Soo; Cho, Gyeong Jae; Choi, Wan Sung; Roh, Gu Seob

    2012-06-01

    Calcineurin (CaN)-mediated excitotoxicity impairs γ-aminobutyric acid (GABA) transmission and induces neuronal apoptosis. Ca(2+)-dependent K(+)-Cl(-) cotransporter 2 (KCC2) participates in GABAergic inhibitory transmission. However, the mechanism by which CaN mediates GABA receptor-mediated KCC2 in seizures is not fully understood. In the present study, we investigated the altered expression of KCC2 and the effects of the CaN inhibitor FK506 on KCC2 expression in the mouse hippocampus following kainic acid (KA) treatment. FK506 was injected twice 24 h and 30 min before KA treatment and then mice were treated with KA and killed 2 days later. FK506 had anticonvulsant effect on KA-induced seizure activities. CaN cleavage was evident in the hippocampus 24 h after KA treatment. FK506 pretreatment blocked the truncation of CaN in the KA-treated hippocampus. Cresyl violet and TUNEL staining showed that FK506 prevented KA-induced hippocampal cell death. In particular, Western blot analysis showed that KCC2 expression was time dependent, with a peak at 6 h and a return to decreased levels at 48 h, whereas FK506 pretreatment inhibited the KA-induced decrease in KCC2 expression in the hippocampus. Immunofluorescence showed that FK506 pretreatment protected the loss of inhibitory GABAergic KCC2-expressing neurons following KA treatment. Taken together, these results provide evidence that altered KCC2 expression may be associated with Ca(2+)-mediated seizure activity and indicate that neuron-specific KCC2 may be involved in neuroprotection after seizures. PMID:22160488

  16. Role of an apical K,Cl cotransporter in urine formation by renal tubules of the yellow fever mosquito (Aedes aegypti)

    PubMed Central

    Hine, Rebecca M.; Schepel, Matthew; Miyauchi, Jeremy; Beyenbach, Klaus W.

    2011-01-01

    The K,Cl cotransporters (KCCs) of the SLC12 superfamily play critical roles in the regulation of cell volume, concentrations of intracellular Cl−, and epithelial transport in vertebrate tissues. To date, the role(s) of KCCs in the renal functions of mosquitoes and other insects is less clear. In the present study, we sought molecular and functional evidence for the presence of a KCC in renal (Malpighian) tubules of the mosquito Aedes aegypti. Using RT-PCR on Aedes Malpighian tubules, we identified five alternatively spliced partial cDNAs that encode putative SLC12-like KCCs. The majority transcript is AeKCC1-A1; its full-length cDNA was cloned. After expression of the AeKCC1-A protein in Xenopus oocytes, the Cl−-dependent uptake of 86Rb+ is 1) activated by 1 mM N-ethylmaleimide and cell swelling, 2) blocked by 100 μM dihydroindenyloxyalkanoic acid (DIOA), and 3) dependent upon N-glycosylation of AeKCC1-A. In Aedes Malpighian tubules, AeKCC1 immunoreactivity localizes to the apical brush border of principal cells, which are the predominant cell type in the epithelium. In vitro physiological assays of Malpighian tubules show that peritubular DIOA (10 μM): 1) significantly reduces both the control and diuretic rates of transepithelial fluid secretion and 2) has negligible effects on the membrane voltage and input resistance of principal cells. Taken together, the above observations indicate the presence of a KCC in the apical membrane of principal cells where it participates in a major electroneutral transport pathway for the transepithelial secretion of fluid in this highly electrogenic epithelium. PMID:21813871

  17. Single-walled carbon nanotubes (SWCNTs) enhance KCl-, acetylcholine-, and serotonin-induced contractions and evoke oxidative stress on rabbit ileum.

    PubMed

    Grasa, Laura; Ansn-Casaos, Alejandro; Martnez, Mara Teresa; Albendea, Raquel; De Martino, Alba; Gonzalo, Sergio; Murillo, Mara Divina

    2014-03-01

    We examined the effects of intravenous administration of purified arc-discharge single-walled carbon nanotubes (SWCNTs) on rabbit ileum to establish the possibility of using these SWCNTs as cell markers or drug carriers for the treatment of intestinal diseases. The SWCNT purification process eliminated carbonaceous impurities and decreased the amount of metals. SWCNTs increased the contractile responses induced by KCl, acetylcholine (ACh), and serotonin (5-HT) in rabbit ileum. Verapamil, apamin, glibenclamide, quinine and charybdotoxin reduced the contractile responses induced by ACh and 5-HT in ileum from rabbits treated with SWCNTs, indicating that voltage-dependent Ca2+ channels and small, intermediate, and large-conductance Ca(2+)-activated, ATP-sensitive, and voltage-dependent K+ channels are involved in these effects. Atropine and hexamethonium reduced the ACh response, indicating that muscarinic and nicotinic receptors are involved in this effect. Ondansetron and GR 113808 reduced the 5-HT response, indicating that serotonin 5-HT3 and 5-HT4 receptors are involved in this effect. SWCNTs increased the malondialdehyde plus 4-hydroxyalkenals and carbonyl levels in rabbit plasma and ileum, indicating that SWCNTs produce oxidative stress. SWCNTs did not produce relevant histological changes or modify the levels of the inflammatory mediators iNOS and COX-2 in the ileum. In conclusion, this study demonstrates that the intravenous administration of SWCNTs can evoke oxidative stress and affect contractility in rabbit ileum. These effects could reduce the possibility of using the arc-discharge SWCNTs as cell markers or drug carriers to treat intestinal diseases. PMID:24730248

  18. Brine-assisted anatexis: Experimental melting in the system haplogranite-H2O-NaCl-KCl at deep-crustal conditions

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    The first-melting temperature of haplogranite in the presence of H2O-NaCl-KCl solutions was determined experimentally at deep-crustal conditions of 6-14 kbar and 700-900 °C. Minimum melting occurs at fluid K/(K+Na) of 0.2-0.25. Melting temperature rises strongly with increasing salinity: at 10 kbar, first melting occurs at 800 °C with a H2O mole fraction (X) of 0.62±0.02, similar to the salinity of fluid inclusions in minerals of some granites and migmatites. At 900 °C and 10 kbar, X is 0.33±0.01 for first melting. All minimum melts are granitic over the entire P-T-X range, with SiO2 melt concentrations of 74±2 wt% on a H2O-free basis and Al2O3 and alkalis typical for granites. Normative quartz is near 30% for all liquids. The K/(K+Na) ratios of minimum melts increase strongly with decreasing H2O activity: at 10 kbar and X=1, K/(K+Na) in the melt is 0.25, whereas at X=0.34 it is 0.55. This "brine trend" is similar to, but more pronounced than, the trend described by decreasing H2O activity in H2O-CO2 fluids, and it better explains the compositions of K-rich granites. Minimum-melting curves in the presence of brines of constant X have strongly positive dP/dT slopes at P>2 kbar, in contrast to vertical or negative dP/dT slopes for those in the presence of H2O-CO2 fluid. There is therefore a wide P-T range over which migrating low-H2O-activity brines may generate subsolidus, deep-crustal metasomatism in the form of K2O and silica enrichment. Moreover, once melting occurs, rising accumulations of granitic magma may be fluid saturated and even increase their melting capacity with decreasing depth because of the strong pressure dependence of H2O activity in salt solutions. Our results offer an explanation for mid-crust migmatization and granite production: rising hot brines may provoke rock melting at some threshold of decreasing depth in the range 15-20 km. Because of their enhanced capacity for metasomatism, leading to eventual melting at granulite facies conditions of temperature, pressure and H2O activity, concentrated brines should be considered as possibly important agents in crustal evolution.

  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. Plant uptake and downward migration of 85Sr and 137Cs after their deposition on to flooded rice fields: lysimeter experiments with and without the addition of KCl and lime.

    PubMed

    Choi, Y H; Lim, K M; Choi, H J; Choi, G S; Lee, H S; Lee, C W

    2005-01-01

    In order to study the plant uptake and downward migration of radiostrontium and radiocesium deposited on to a flooded rice field, 85Sr and 137Cs were applied to the standing water over an acidic sandy soil in planted lysimeters. The plant uptake was quantified with the areal transfer factor (TFa, m2 kg(-1)-dry plant). Following the spiking 14 days after transplanting, the TFa values for the hulled seeds were 3.9 x 10(-4) for 85Sr and 1.4 x 10(-4) for 137Cs, whereas those for the straws were 1.3 x 10(-2) and 3.2 x 10(-4), respectively. The 137Cs TFa from the spiking at the anthesis/milky-ripe stage was several times higher than that from the earlier spiking, whereas the difference was much less in the 85Sr TFa. Such an increase in the 137Cs TFa was attributed mainly to an enhanced plant-base uptake. The addition of KCl and lime after the spiking significantly reduced the TFa values of both radionuclides. The reducing effect was greater for the later spiking. An appreciable fraction of the applied activity leached out of the lysimeter for 85Sr, whereas a negligible fraction leached for 137Cs. The leaching was remarkably increased by the KCl and lime addition for both. A conspicuous localization of 137Cs with respect to the soil surface was observed. In a batch experiment, the 137Cs concentration in the standing water decreased more rapidly than that of 85Sr, both of which were fitted to the power functions of the elapsed time. To add KCl and lime slowed such decreases to lessen the distribution coefficients (Kd) of both 85Sr and 137Cs. PMID:15465178

  2. 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.

  3. Habit changes of lead chloride, PbCl 2, caused by growth from pure aqueous solution and the effect of KCl, NH 4Cl, CdCl 2 and HCl as additives

    NASA Astrophysics Data System (ADS)

    Van Panhuys-Sigler, M.; Hartman, P.; Woensdregt, C. F.

    1988-03-01

    Crystallization of lead chloride, PbCl 2, from pure aqueous solution produces crystals with dominant {211} and smaller {010} and {100} faces at low supersaturation. Increase of supersaturation yields crystals elongated along the c axis. Growth from a previously prepared saturated solution gives crystals elongated along the c axis with {011} as main terminal faces. This habit also occurs when KCl, NH 4Cl or CdCl 2 or mixtures of these are added to a freshly prepared supersaturated solution. Only at low additive concentration and at low supersaturation {211} is dominant. The latter habit is supposed to be caused by adsorption of OH - ions on {211}. A deposit of Pb(OH)Cl has been observed. Crystallization from HCl containing solutions enhances the {010} and {121} forms, presumably through preferred adsorption of H + and possibly PbCl -3 ions. Increasing supersaturation diminishes the effect of the habit modifying process until the stage where dendrites appear.

  4. 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.

    2016-02-01

    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 GΩm).

  5. An in vivo study on the reaction of hydroxyapatite-sol injected into blood.

    PubMed

    Aoki, H; Aoki, H; Kutsuno, T; Li, W; Niwa, M

    2000-02-01

    In order to identify the possibility of hydroxyapatite-sol being used as a drug carrier and absorbent, an in vivo experimental study was performed. Pure hydroxyapatite microcrystals were synthesized by reaction of high purity Ca(OH)2 and H3PO4 solutions while using an ultrasonic homogenizer. Hydroxyapatite-sol was prepared by dispersing hydroxyapatite microcrystals into physiological salt solution. The hydroxyapatite-sol in different concentrations was injected into veins of both 25 Wistar rats and 5 Beagle dogs. The medium lethal dose was determined as 160 mg/kg. By observing the change of O2 and CO2 gas partial pressure, it was considered that the main cause of death by hydroxyapatite-sol injection was due to the blockage of capillaries. When one-sixth amount of the medium lethal dose was injected into the veins of the dogs, the value of phosphorous increased but calcium and magnesium kept stable. LDH, CPK, GOP and GDT values dramatically increased in 30 min after injection, however, one day after injection, the values returned to normal. Repeated experiments by similar methods were continued on same animals for 2 years in two-week intervals, the results in every experiment were almost same, no chronic damage or permanent side effects were discovered in the two years experiment. According to the results above, it was suggested that the hydroxyapatite-sol could be applied as a drug carrier into blood by using a small amount less than one-sixth of the medium lethal dose. PMID:15348049

  6. Ball milling pretreatment of corn stover for enhancing the efficiency of enzymatic hydrolysis.

    PubMed

    Lin, Zengxiang; Huang, He; Zhang, Hongman; Zhang, Lin; Yan, Lishi; Chen, Jingwen

    2010-11-01

    Ethanol can be produced from lignocellulosic biomass with the usage of ball milling pretreatment followed by enzymatic hydrolysis and fermentation. The sugar yields from lignocellulosic feed stocks are critical parameters for ethanol production process. The research results from this paper indicated that the yields of glucose and xylose were improved by adding any of the following dilute chemical reagents: H(2)SO(4), HCl, HNO(3), CH(3)COOH, HCOOH, H(3)PO(4), and NaOH, KOH, Ca(OH)(2), NH(3)·H(2)O in the ball milling pretreatment of corn stover. The optimal enzymatic hydrolysis efficiencies were obtained under the conditions of ball milling in the alkali medium that was due to delignification. The data also demonstrated that ball milling pretreatment was a robust process. From the microscope image of ball milling-pretreated corn stover, it could be observed that the particle size of material was decreased and the fiber structure was more loosely organized. Meanwhile, the results indicate that the treatment effect of wet milling is better than that of dry milling. The optimum parameters for the milling process were ball speed of 350 r/min, solid/liquid ratio of 1:10, raw material particle size with 0.5 mm, and number of balls of 20 (steel ball, Φ = 10 mm), grinding for 30 min. In comparison with water milling process, alkaline milling treatment could increase the enzymatic hydrolysis efficiency of corn stover by 110%; and through the digestion process with the combination of xylanase and cellulase mixture, the hydrolysis efficiency could increase by 160%. PMID:20593309

  7. Utility of reaction intermediate monitoring with photodissociation multi-stage (MSn) time-of-flight mass spectrometry for mechanistic and structural studies: Phosphopeptides

    NASA Astrophysics Data System (ADS)

    Moon, Jeong Hee; Shin, Young Sik; Kim, Myung Soo

    2009-12-01

    In tandem mass spectra of phosphopeptides, intact sequence ions are often missing or appear weakly. Instead, dephosphorylated sequence ions appear prominently. In this work, we used photodissociation (PD) multi-stage (MSn) time-of-flight mass spectrometry that can monitor reaction intermediates with lifetime as short as 100 ns to study the formation of dephosphorylated sequence ions such as yn-H3PO4. yn-H3PO4 was found to be formed mainly by H3PO4 loss from yn. For doubly phosphorylated peptides, yn seemed to lose H3PO4 stepwise and form yn-H3PO4 and yn-2H3PO4. Even when yn was absent in PD-MS2 spectrum, its m/z could be predicted from those of yn-H3PO4 and/or yn-2H3PO4. Complete sequence coverage was possible when the data from PD-MS2 and PD-MS3 were combined, demonstrating the utility of transient ion detection by PD-MS3 for structure analysis.

  8. Memantine treatment reduces the expression of the K(+)/Cl(-) cotransporter KCC2 in the hippocampus and cerebral cortex, and attenuates behavioural responses mediated by GABA(A) receptor activation in mice.

    PubMed

    Molinaro, Gemma; Battaglia, Giuseppe; Riozzi, Barbara; Di Menna, Luisa; Rampello, Liborio; Bruno, Valeria; Nicoletti, Ferdinando

    2009-04-10

    A 7-day treatment with memantine (25 mg/kg, i.p.), a drug that is currently prescribed for the treatment of Alzheimer's disease, increased the levels of brain-derived neurotrophic factor (BDNF) and reduced the expression of the neuron-specific K(+)/Cl(-) co-transporter, KCC2, in the hippocampus and cerebral cortex of mice. Knowing that KCC2 maintains low intracellular Cl(-) concentrations, which drive Cl(-) influx in response to GABA(A) receptor activation, we monitored the behavioural response to the GABA(A) receptor enhancer, diazepam, in mice pre-treated for 7 days with saline or 25 mg/kg of memantine. Memantine treatment substantially attenuated motor impairment induced by an acute challenge with diazepam (6 mg/kg, i.p.), as assessed by the rotarod test and the horizontal wire test. We suggest that a prolonged treatment with memantine induces changes in the activity of GABA(A) receptors that might contribute to the therapeutic and/or toxic effects of the drug. PMID:19236854

  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 (γ =1) and H2 (γ =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. Phosphoric acid activation of Morrocan oil shale of Timahdit: Influence of the experimental conditions on yield and surface area of adsorbents

    NASA Astrophysics Data System (ADS)

    Ichcho, S.; Khouya, E.; Abourriche, A.; Ezzine, M.; Hannache, H.; Naslain, R.; Pailler, R.

    2005-03-01

    The use of Moroccan oil shale for the preparation of adsorbents by chemical activation with phosphoric acid is analysed. The results indicate that this material is promising for this application. The effect of different conditions of preparation on the yield and surface area is discussed. These parameters are H{3}PO{4}/shale weight ratio, carbonisation temperature, carbonisation time and concentration of H{3}PO{4}.

  12. Modification of surface pretreatment of white spot lesions to improve the safety and efficacy of resin infiltration

    PubMed Central

    Yim, Hyun-Kyung; Min, Ji-Hyun; Kwon, Ho-Keun

    2014-01-01

    Objective A low-viscosity resin (infiltrant) was used to inhibit the progression of white spot lesions (WSLs) and resolve associated esthetic issues. An alternative pretreatment was explored to increase the pore volume of the surface layer of the WSLs. Also, the penetration effects of the infiltrant were evaluated for various pretreatments. Methods Sixty two artificial lesions were fabricated on bovine teeth. As a positive control, 15% HCl gel was applied for 120 seconds. Further, 37% H3PO4 gel was applied for 30 seconds using three methods. The samples were divided as follows: H3PO4 only group, H3PO4 sponge group, and H3PO4 brush group. The acid was gently rubbed with the applicators (i.e., a sponge or brush) throughout the application time. To compare the effects of resin infiltration, twenty paired halves of specimens were treated with an infiltrant (ICON®). Results Thicknesses of the removed surface layers and infiltrated areas were evaluated by confocal laser scanning microscope. The positive control and the 37% H3PO4 brush group failed to show significant differences in the removed thickness (p > 0.05); however, the mean percentage of the infiltrated area was higher in the 37% H3PO4 brush group (84.13 ± 7.58%) than the positive control (63.51 ± 7.62%, p < 0.001). Scanning electron microscope observations indicate higher pore volumes for the 37% H3PO4 brush group than for the positive control. Conclusions Application of 37% H3PO4 with a brush for 30 seconds increased the pore volume of WSL surface layers and the percentage of infiltrated areas in comparison to the use of 15% HCl for 120 seconds. PMID:25133134

  13. The effect of phosphoric acid concentration on electrocatalysis

    NASA Astrophysics Data System (ADS)

    Glass, Jeffrey T.; Cahen, George L., Jr.; Stoner, Glenn E.

    1989-03-01

    Phosphoric acid (H3PO4) is the electrolyte used in the most advanced H2/air fuel cell developed for power generation and for on-site integrated energy systems. Oxygen reduction kinetics in this electrolyte are relatively poor and thus limit the efficiency of such fuel cells. Therefore, in order to better understand oxygen interactions with platinum in these cells, oxygen adsorption and the kinetics of oxygen reduction reaction (ORR) were studied utilizing a Pt rotating disk electrode in several concentrations of highly purified H3PO4. Although the kinetics of the ORR remained first order in all concentrations, it was found that its Tafel slope increased from about 110 mV/dec in low H3PO4 concentrations to about 134 mV/dec in 85 wt pct H3PO4. Anodic adsorption isotherms indicated that the higher H3PO4 concentrations also hindered adsorption of oxygen from solution. These effects were attributed to the blockage of electroactive sites by the adsorption of H3PO4 molecules.

  14. Computer simulation study of the intermolecular structure of phosphoric acid-N,N-dimethylformamide mixtures.

    PubMed

    Fedorova, Irina V; Kiselev, Michael G; Safonova, Lyubov P

    2015-01-01

    The structures and energies of the complexes (H3PO4)2, H3PO4-DMF, and (H3PO4)2-DMF were analyzed at the B3LYP level of approximation. It was found that H-bonds form between H3PO4 and DMF molecules, but the strength of the H-bond depends strongly on its molecular environment. Effects of the solvent were taken into account via the CPCM approach. According to the B3LYP-СPCM calculations, the O···O distance in (H3PO4)2-DMF is shorter and its H-bonds are stronger than in the other complexes studied. In order to study the effects of concentration on the intermolecular structure, molecular dynamics simulations of H3PO4-DMF mixtures with mole fractions of acid of <0.1 were performed. The calculations indicated that the largest fraction of the acid protons are involved in hydrogen bonding with oxygen atoms of the DMF molecules. An increased probability of acid-acid hydrogen-bond formation at phosphoric acid mole fractions >0.06 was also noted. PMID:25617205

  15. Surface properties and early murine pre-osteoblastic cell responses of phosphoric acid modified titanium surface

    PubMed Central

    Osathanon, Thanaphum; Sawangmake, Chenphop; Ruangchainicom, Nanticha; Wutikornwipak, Pavitra; Kantukiti, Panisa; Nowwarote, Nunthawan; Pavasant, Prasit

    2015-01-01

    Aims The present study investigated the surface properties and murine pre-osteoblast cell (MC3T3-E1) responses of phosphoric acid (H3PO4) treated commercially pure titanium. Methods Titanium discs were treated with various concentration of H3PO4 (5%, 10%, and 20%; v/v) at 90 °C for 30 min. Surface properties were evaluated by profilometer, contact angle meter, and scanning electron microscopy (SEM) with energy dispersive X-rays. MC3T3-E1 attachment and spreading were evaluated by SEM and phalloidin immunohistochemistry staining. Results Surface roughness and wettability were not statistically difference among all experimental and control groups. Phosphate and oxygen were detected on H3PO4 treated surfaces. At 20 min, cell attachment was significantly higher in 10% and 20% H3PO4 treated groups compared to the control. Cells exhibited orientated-cytoskeleton fibers on 20% H3PO4 modified titanium surface. Though, there was no difference in cell spreading stage among all treatment groups. Conclusion H3PO4 treatment on titanium may influence early cell response, particularly on attachment and spreading. PMID:26937362

  16. 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 2.0 h 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

  17. Bioactivity studies and adhesion of human osteoblast (hFOB) on silicon-biphasic calcium phosphate material.

    PubMed

    Ibrahim, S; Sabudin, S; Sahid, S; Marzuke, M A; Hussin, Z H; Kader Bashah, N S; Jamuna-Thevi, K

    2016-01-01

    Surface reactivity of bioactive ceramics contributes in accelerating bone healing by anchoring osteoblast cells and the connection of the surrounding bone tissues. The presence of silicon (Si) in many biocompatible and bioactive materials has been shown to improve osteoblast cell adhesion, proliferation and bone regeneration due to its role in the mineralisation process around implants. In this study, the effects of Si-biphasic calcium phosphate (Si-BCP) on bioactivity and adhesion of human osteoblast (hFOB) as an in vitro model have been investigated. Si-BCP was synthesised using calcium hydroxide (Ca(OH)2) and phosphoric acid (H3PO4) via wet synthesis technique at Ca/P ratio 1.60 of material precursors. SiO2 at 3 wt% based on total precursors was added into apatite slurry before proceeding with the spray drying process. Apatite powder derived from the spray drying process was pressed into discs with Ø 10 mm. Finally, the discs were sintered at atmospheric condition to obtain biphasic hydroxyapatite (HA) and tricalcium phosphate (TCP) peaks simultaneously and examined by XRD, AFM and SEM for its bioactivity evaluation. In vitro cell viability of L929 fibroblast and adhesion of hFOB cell were investigated via AlamarBlue® (AB) assay and SEM respectively. All results were compared with BCP without Si substitution. Results showed that the presence of Si affected the material's surface and morphology, cell proliferation and cell adhesion. AFM and SEM of Si-BCP revealed a rougher surface compared to BCP. Bioactivity in simulated body fluid (SBF) was characterised by pH, weight gain and apatite mineralisation on the sample surface whereby the changes in surface morphology were evaluated using SEM. Immersion in SBF up to 21 days indicated significant changes in pH, weight gain and apatite formation. Cell viability has demonstrated no cytotoxic effect and denoted that Si-BCP promoted good initial cell adhesion and proliferation. These results suggest that Si-BCP's surface roughness (164 nm) was significantly higher than BCP (88 nm), thus enhancing the adhesion and proliferation of the osteoblast. PMID:26858566

  18. Bioactivity studies and adhesion of human osteoblast (hFOB) on silicon-biphasic calcium phosphate material

    PubMed Central

    Ibrahim, S.; Sabudin, S.; Sahid, S.; Marzuke, M.A.; Hussin, Z.H.; Kader Bashah, N.S.; Jamuna-Thevi, K.

    2015-01-01

    Surface reactivity of bioactive ceramics contributes in accelerating bone healing by anchoring osteoblast cells and the connection of the surrounding bone tissues. The presence of silicon (Si) in many biocompatible and bioactive materials has been shown to improve osteoblast cell adhesion, proliferation and bone regeneration due to its role in the mineralisation process around implants. In this study, the effects of Si-biphasic calcium phosphate (Si-BCP) on bioactivity and adhesion of human osteoblast (hFOB) as an in vitro model have been investigated. Si-BCP was synthesised using calcium hydroxide (Ca(OH)2) and phosphoric acid (H3PO4) via wet synthesis technique at Ca/P ratio 1.60 of material precursors. SiO2 at 3 wt% based on total precursors was added into apatite slurry before proceeding with the spray drying process. Apatite powder derived from the spray drying process was pressed into discs with Ø 10 mm. Finally, the discs were sintered at atmospheric condition to obtain biphasic hydroxyapatite (HA) and tricalcium phosphate (TCP) peaks simultaneously and examined by XRD, AFM and SEM for its bioactivity evaluation. In vitro cell viability of L929 fibroblast and adhesion of hFOB cell were investigated via AlamarBlue® (AB) assay and SEM respectively. All results were compared with BCP without Si substitution. Results showed that the presence of Si affected the material’s surface and morphology, cell proliferation and cell adhesion. AFM and SEM of Si-BCP revealed a rougher surface compared to BCP. Bioactivity in simulated body fluid (SBF) was characterised by pH, weight gain and apatite mineralisation on the sample surface whereby the changes in surface morphology were evaluated using SEM. Immersion in SBF up to 21 days indicated significant changes in pH, weight gain and apatite formation. Cell viability has demonstrated no cytotoxic effect and denoted that Si-BCP promoted good initial cell adhesion and proliferation. These results suggest that Si-BCP’s surface roughness (164 nm) was significantly higher than BCP (88 nm), thus enhancing the adhesion and proliferation of the osteoblast. PMID:26858566

  19. 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

  20. 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

  1. Physicochemical properties of phosphate ester from palm kernel oil

    NASA Astrophysics Data System (ADS)

    Adawiyah Norzali, Nor Rabbi'atul; Badri, Khairiah Haji; Ahmad, Ishak

    2013-12-01

    The physicochemical properties of phosphate ester from palm kernel oil have been studied. The phosphate ester was synthesized via ring-opening of epoxidized palm kernel oil with phosphoric acid. The amount of phosphoric acid (H3PO4) was varied at 0, 2.5, 5.0 and 7.5 wt%. Acid values of PKO and EPKO were 1.85 and 1.87 mg KOH/g respectively. However, the acid values increased with increasing amount of H3PO4 with values of 10.62 mg KOH/g, 31.34 mg KOH/g and 110.95 mg KOH/g respectively. The hydrolysis of the EPKO has successfully converted it to PEPKO with hydroxyl value of 16.16 mg KOH/g, 26.90 and 35.33 mg KOH/g at H3PO4 of 2.5, 5.0, and 7.5wt%.

  2. Porous texture of activated carbons prepared by phosphoric acid activation of woods

    NASA Astrophysics Data System (ADS)

    Díaz-Díez, M. A.; Gómez-Serrano, V.; Fernández González, C.; Cuerda-Correa, E. M.; Macías-García, A.

    2004-11-01

    Activated carbons (ACs) have been prepared using chestnut, cedar and walnut wood shavings from furniture industries located in the Comunidad Autónoma de Extremadura (SW Spain). Phosphoric acid (H3PO4) at different concentrations (i.e. 36 and 85 wt.%) has been used as activating agent. ACs have been characterized from the results obtained by N2 adsorption at 77 K. Moreover, the fractal dimension (D) has been calculated in order to determine the AC surface roughness degree. Optimal textural properties of ACs have been obtained by chemical activation with H3PO4 36 wt.%. This is corroborated by the slightly lower values of D for samples treated with H3PO4 85 wt.%.

  3. Temperature effect on the corrosion and passivation characterization of Ni82.3Cr7Fe3Si4.5B3.2 alloy in acidic media

    NASA Astrophysics Data System (ADS)

    Emran, Khadijah M.; Arab, Sanaa T.; Al-Turkustani, Aisha M.; Al-Turaif, Hamad A.

    2016-02-01

    The effects of temperature on corrosion and the electrochemical behavior of Ni82.3Cr7Fe3Si4.5B3.2 glassy alloy in HCl, H2SO4, and H3PO4 acids were studied using AC and DC techniques. Impedance data reveal that the susceptibility to localized corrosion increases with increasing temperature. Potentiodynamic polarization curves reveal that the bulk glassy alloy is spontaneously passivated at all the investigated temperature in H2SO4 and H3PO4 solutions. A localized corrosion effect in HCl solution is clearly observed. The apparent activation energies in the regions of Tafel, active, and passive, as well as the enthalpies and entropies of the dissolution process were determined and discussed. The high apparent activation energy ( E a) value for H3PO4 solution in Tafel region is explained by the low aggressivity of PO 4 3- ions.

  4. Synthesis of sodium lauryl sulphate (SLS)-modified activated carbon from risk husk for waste lead (Pb) removal

    NASA Astrophysics Data System (ADS)

    Al-Latief, D. N.; Arnelli, Astuti, Y.

    2015-12-01

    Surfactant-modified active carbon (SMAC) has been successfully synthesized from waste rice husk using a series of treatments i.e. carbonization, activation with H3PO4 and surface modification using sodium lauryl sulfate (SLS). The synthesized SMAC was characterized using SEM-EDX and FTIR. The adsorption results show that the SMAC synthesized using H3PO4 treatment for 8 hours followed with SLS treatment for 5 hours had efficiency and capacity of the waste lead removal of 99.965% and 0.499825 mg.g-1, respectively.

  5. 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.

  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. 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...

  8. 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...

  9. 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.

  10. Titanate nanotube thin films with enhanced thermal stability and high-transparency prepared from additive-free sols

    NASA Astrophysics Data System (ADS)

    Kőrösi, László; Papp, Szilvia; Hornok, Viktória; Oszkó, Albert; Petrik, Péter; Patko, Daniel; Horvath, Robert; Dékány, Imre

    2012-08-01

    Titanate nanotubes were synthesized from TiO2 in alkaline medium by a conventional hydrothermal method (150 °C, 4.7 bar). To obtain hydrogen titanates, the as-prepared sodium titanates were treated with either HCl or H3PO4 aqueous solutions. A simple synthesis procedure was devised for stable titanate nanotube sols without using any additives. These highly stable ethanolic sols can readily be used to prepare transparent titanate nanotube thin films of high quality. The resulting samples were studied by X-ray diffraction, N2-sorption measurements, Raman spectroscopy, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The comparative results of using two kinds of acids shed light on the superior thermal stability of the H3PO4-treated titanate nanotubes (P-TNTs). X-ray photoelectron spectroscopy revealed that P-TNTs contains P in the near-surface region and the thermal stability was enhanced even at a low (˜0.5 at%) concentration of P. After calcination at 500 °C, the specific surface areas of the HCl- and H3PO4-treated samples were 153 and 244 m2 g-1, respectively. The effects of H3PO4 treatment on the structure, morphology and porosity of titanate nanotubes are discussed.

  11. Chemical etching behaviors of semipolar (11̄22) and nonpolar (11̄20) gallium nitride films.

    PubMed

    Jung, Younghun; Baik, Kwang Hyeon; Mastro, Michael A; Hite, Jennifer K; Eddy, Charles R; Kim, Jihyun

    2014-08-14

    Wet chemical etching using hot KOH and H3PO4 solutions was performed on semipolar (11̄22) and nonpolar (11̄20) GaN films grown on sapphire substrates. An alternating KOH/H3PO4/KOH etch process was developed to control the orientation of the facets on the thin-film surface. The initial etch step in KOH produced c- and m-plane facets on the surface of both semipolar (11̄22) and nonpolar (11̄20) GaN thin-films. A second etch step in H3PO4 solution additionally exposed a (̄1̄12̄2) plane, which is chemically stable in H3PO4 solution. By repeating the chemical etch with KOH solution, the m-plane facets as seen in the original KOH etch step were recovered. The etching methods developed in our work can be used to control the surface morphologies of nonpolar and semipolar GaN-based optoelectronic devices such as light-emitting diodes and solar cells. PMID:24971494

  12. 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 ...

  13. Enhanced xylose recovery from oil palm empty fruit bunch by efficient acid hydrolysis.

    PubMed

    Tan, Hooi Teng; Dykes, Gary A; Wu, Ta Yeong; Siow, Lee Fong

    2013-08-01

    Oil palm empty fruit bunch (EFB) is abundantly available in Malaysia and it is a potential source of xylose for the production of high-value added products. This study aimed to optimize the hydrolysis of EFB using dilute sulfuric acid (H2SO4) and phosphoric acid (H3PO4) via response surface methodology for maximum xylose recovery. Hydrolysis was carried out in an autoclave. An optimum xylose yield of 91.2 % was obtained at 116 C using 2.0 % (v/v) H2SO4, a solid/liquid ratio of 1:5 and a hydrolysis time of 20 min. A lower optimum xylose yield of 24.0 % was observed for dilute H3PO4 hydrolysis at 116 C using 2.4 % (v/v) H3PO4, a solid/liquid ratio of 1:5 and a hydrolysis time of 20 min. The optimized hydrolysis conditions suggested that EFB hydrolysis by H2SO4 resulted in a higher xylose yield at a lower acid concentration as compared to H3PO4. PMID:23709290

  14. 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

  15. Determination of the calcium species in coal chars by Ca K-edge XANES analysis

    NASA Astrophysics Data System (ADS)

    Liu, Li-Juan; Liu, Hui-Jun; Cui, Ming-Qi; Hu, Yong-Feng; Zheng, Lei; Zhao, Yi-Dong; Ma, Chen-Yan; Xi, Shi-Bo; Yang, Dong-Liang; Guo, Zhi-Ying; Wang, Jie

    2013-02-01

    Ca-based additives have been widely used as a sulfur adsorbent during coal pyrolysis and gasification. The Ca speciation and evolution during the pyrolysis of coal with Ca additives have attracted great attention. In this paper, Ca species in the coal chars prepared from the pyrolysis of Ca(OH)2 or CaCO3-added coals are studied by using Ca K-edge X-ray absorption near-edge structural spectroscopy. The results demonstrate that Ca(OH)2, CaSO4, CaS and CaO coexist in the Ca(OH)2-added chars, while Ca(OH)2 and CaSO4 are the main species in the Ca(OH)2-added chars. Besides, a carboxyl-bound Ca is also formed during both the pyrolysis for the Ca(OH)2-added and the CaCO3-added coals. A detailed discussion about the Ca speciation is given.

  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| > 4σ( 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 2CaО · 3В2О3 · nH2О ( n = 0-13) with the constant CaО: В2О3= 2: 3 ratio and variable content of water is performed.

  19. 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

  20. 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 Ω 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 Ω 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.

  1. 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

  2. Surface enhanced Raman spectroscopy of the silver/KCl, triethylenediamine (DABCO), water system

    NASA Astrophysics Data System (ADS)

    Irish, D. E.; Guzonas, D.; Atkinson, G. F.

    1985-07-01

    1,4-Diazabicyclo[2.2.2]octane, (N(CH 2CH 2) 3N), usually abbreviated DABCO or DBO, is a symmetric top molecule of point group D 3h. SERS experiments have been carried out in an optical electrochemical cell using a silver electrode roughened by a single oxidation-reduction cycle (ORC). The observed SERS spectra contained four strong bands at 624, 798, 990 and 1351 cm -1, all A' 1 totally symmetric modes. The same bands were also observed in SERS spectra of DABCO adsorbed on colloidal gold. In the electrochemical experiments, the maximum of SERS-intensity versus electrode potential plots was observed to shift to less negative potentials as the wavelength of the exciting line was shifted to the red. The radically-altered, relative intensities of the observed bands, as well as observed changes in relative intensity as a function of electrode potential, have been interpreted as a selective enhancement of those normal modes which have as a major component of vibrational motion the C-C stretch. These observations are correlated with current theories concerning the SERS mechanism, especially those involving charge transfer (CT).

  3. 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.

  4. Color center formation in KCl and KBr single crystals with femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Dickinson, J. T.; Langford, S. C.; Avanesyan, S. M.; Orlando, S.

    2007-07-01

    Because of their extremely high instantaneous powers, femtosecond lasers can color many nominally transparent materials. Although the excitations responsible for this defect formation occur on subpicosecond time scales, subsequent interactions between the resulting electronic and lattice defects complicate the evolution of color center formation and decay. These interactions must be understood in order to account for the long-term behavior of coloration. In this work, we probe the evolution of color centers generated by femtosecond laser radiation in potassium chloride and potassium bromide single crystals on time scales from microseconds to hundreds of seconds. By using an appropriately chosen probe laser focused through the femtosecond laser spot, we follow the changes in coloration due to individual or multiple femtosecond pulses and the evolution of that coloration for long times after femtosecond laser radiation is terminated.

  5. 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.

  6. Preparation of a novel rape pollen shell microencapsulation and its use for protein adsorption and pH-controlled release.

    PubMed

    Ma, Hongbo; Zhang, Peiqi; Wang, Jidong; Xu, Xianju; Zhang, Hui; Zhang, Zhenhua; Zhang, Yongchun; Ning, Yunwang

    2014-01-01

    This study aims to synthesize hollow microspheres (HMS) from rape pollen via H3PO4 hydrothermal carbonization. The rape pollen hollow shell was used as the carrier and bovine serum albumin as a model protein. The properties of HMS were characterized by scanning electron microscope (SEM), solid-state nuclear magnetic resonance and elemental analysis. The SEM images clearly showed that the HMS had perfect spherical morphology and porous hollow surface. In the separated filtrate, a large number of sucroses were detected by high-performance liquid chromatography, suggesting that the hydrolysis of starch molecules occurred during the hydrothermal process. The formation of HMS was that the rape pollen inclusion was removed from rape pollen shell to preserve integral HMS by H3PO4 hydrothermal. The HMS possessed amphiphilic surfaces, which was suitable for protein adsorpion and pH-controlled release application. PMID:24963958

  7. Production of technical grade phosphoric acid from incinerator sewage sludge ash (ISSA).

    PubMed

    Donatello, S; Tong, D; Cheeseman, C R

    2010-01-01

    The recovery of phosphorus from sewage sludge ash samples obtained from 7 operating sludge incinerators in the UK using a sulfuric acid washing procedure to produce a technical grade phosphoric acid product has been investigated. The influences of reaction time, sulfuric acid concentration, liquid to solid ratio and source of ISSA on P recovery have been examined. The optimised conditions were the minimum stoichiometric acid requirement, a reaction time of 120 min and a liquid to solid ratio of 20. Under these conditions, average recoveries of between 72% and 91% of total phosphorus were obtained. Product filtrate was purified by passing through a cation exchange column, concentrated to 80% H(3)PO(4) and compared with technical grade H(3)PO(4) specifications. The economics of phosphate recovery by this method are briefly discussed. PMID:20434899

  8. 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

  9. The performance of supercapacitor electrodes developed from chemically activated carbon produced from waste tea

    NASA Astrophysics Data System (ADS)

    Inal, I. Isil Gurten; Holmes, Stuart M.; Banford, Anthony; Aktas, Zeki

    2015-12-01

    Highly microporous and mesoporous activated carbons were produced from waste tea for application as supercapacitor electrodes, utilising a chemical activation method involving treatment with either K2CO3 or H3PO4. The area, pore structure characteristics and surface functionality of the activated carbons were evaluated to investigate the influence on electrochemical performance. The performance of the activated carbons as supercapacitor electrodes was tested by cyclic voltammetry (CV), impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD) measurements, in an aqueous electrolyte. The results showed that the pore structure and type of the activated carbon have significant impact on the supercapacitor performance. Both waste tea-based activated carbon electrodes showed good cyclic stability. However, despite its lower specific surface area the highly microporous activated carbon produced with K2CO3, exhibited much better capacitive performance than that of the mesoporous activated carbon produced with H3PO4.

  10. Sweeping of hydrophobic amines under inhomogeneous electric field and low surfactant concentration in micellar electrokinetic chromatography.

    PubMed

    Ciura, Krzesimir; Kowalski, Piotr; Nowakowska, Joanna; Markuszewski, Michał; Bączek, Tomasz; Dziomba, Szymon

    2016-05-01

    The influence of sample matrix on sample sweeping in MEKC was examined in the presented manuscript. Significant focusing effect was observed for relatively hydrophobic cationic compounds (emetine, strychnine and quinine) using high ionic strength sample matrix (900 mM H3 PO4 /720 mM Tris) which conductivity was about ninefold higher than utilized BGE. Moreover, the results were obtained using BGE composed of comparatively low surfactant concentration (10 mM SDS) and 40 mM H3 PO4 /32 mM Tris buffer solution. About 200 to 300-fold preconcentration of analytes was reached with the presented method. Basing on experimental results and computer simulation using Simul5 software, hypothetical mechanism of observed phenomenon was proposed. PMID:27135308

  11. Influence of the experimental conditions on porosity and structure of adsorbents elaborated from Moroccan oil shale of Timahdit by chemical activation.

    PubMed

    Ichcho, S; Khouya, E; Fakhi, S; Ezzine, M; Hannache, H; Pallier, R; Naslain, R

    2005-02-14

    This study records experiments undertaken to determine the suitable conditions for the use of the oil shale of Timahdit, as an adsorbent for water treatment. A simple process was proposed based on chemical activation. The preparation has been carried out by carbonization after impregnation of the precursor with phosphoric acid. The effect of different conditions of preparation on the specific surface area is discussed. These parameters are H3PO4/shale weight ratio, carbonization temperature, carbonization time and concentration of H3PO4. The properties and surface structure of the adsorbent were investigated by XPS and FT-IR. Their total surface acidity and basicity were also determined. The retention process of methylene blue (MB) by adsorbents has been studied. It was found that MHP2 and MHP7 have relatively high retention ability as compared to activated carbons. PMID:15721527

  12. 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.

  13. Mechanistic Investigation of Phosphate Ester Bond Cleavages of Glycylphosphoserinyltryptophan Radical Cations under Low-Energy Collision-Induced Dissociation

    NASA Astrophysics Data System (ADS)

    Quan, Quan; Hao, Qiang; Song, Tao; Siu, Chi-Kit; Chu, Ivan K.

    2013-04-01

    Under the conditions of low-energy collision-induced dissociation (CID), the canonical glycylphosphoserinyltryptophan radical cation having its radical located on the side chain of the tryptophan residue ([G p SW]•+) fragments differently from its tautomer with the radical initially generated on the α-carbon atom of the glycine residue ([G• p SW]+). The dissociation of [G• p SW]+ is dominated by the neutral loss of H3PO4 (98 Da), with backbone cleavage forming the [b2 - H]•+/y1 + pair as the minor products. In contrast, for [G p SW]•+, competitive cleavages along the peptide backbone, such as the formation of [G p SW - CO2]•+ and the [c2 + 2H]+/[z1 - H]•+ pair, significantly suppress the loss of neutral H3PO4. In this study, we used density functional theory (DFT) to examine the mechanisms for the tautomerizations of [G• p SW]+ and [G p SW]•+ and their dissociation pathways. Our results suggest that the dissociation reactions of these two peptide radical cations are more efficient than their tautomerizations, as supported by Rice-Ramsperger-Kassel-Marcus (RRKM) modeling. We also propose that the loss of H3PO4 from both of these two radical cationic tautomers is preferentially charge-driven, similar to the analogous dissociations of even-electron protonated peptides. The distonic radical cationic character of [G• p SW]+ results in its charge being more mobile, thereby favoring charge-driven loss of H3PO4; in contrast, radical-driven pathways are more competitive during the CID of [G p SW]•+.

  14. 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

  15. Efficacy of a combined nanoparticulate/calcium hydroxide root canal medication on elimination of Enterococcus faecalis.

    PubMed

    Javidi, Maryam; Afkhami, Farzaneh; Zarei, Mina; Ghazvini, Kiarash; Rajabi, Omid

    2014-08-01

    The purpose of this study was to evaluate the efficacy of Ca(OH)2 with or without a silver nanoparticle suspension to eliminate Enterococcus faecalis from root canals. A total of 66 extracted human single-rooted teeth contaminated with E. faecalis were treated with 10% Ca(OH)2 alone, Ca(OH)2 with nanosilver or sterile water (as a negative control). Samples were obtained with paper points and Gates-Glidden burs at 1 and 7 days after root canal preparation and the number of colony-forming units (CFU) was determined. The number of CFUs observed after dressing with Ca(OH)2  + nanosilver was significantly less than the number observed with Ca(OH)2 alone after 1 or 7 days (P < 0.001, P < 0.001). No differences in antimicrobial properties were observed between the two time points in the Ca(OH)2  + nanosilver group (P > 0.05). Higher antimicrobial efficacy was observed in the Ca(OH)2 group after 7 days than 1 day (P < 0.001). This study highlighted the potential advantage of using a mixture of Ca(OH)2 and nanosilver for intracanal medicament. PMID:25244219

  16. Formation and Dissociation of Phosphorylated Peptide Radical Cations

    NASA Astrophysics Data System (ADS)

    Kong, Ricky P. W.; Quan, Quan; Hao, Qiang; Lai, Cheuk-Kuen; Siu, Chi-Kit; Chu, Ivan K.

    2012-12-01

    In this study, we generated phosphoserine- and phosphothreonine-containing peptide radical cations through low-energy collision-induced dissociation (CID) of the ternary metal-ligand phosphorylated peptide complexes [CuII(terpy) p M]·2+ and [CoIII(salen) p M]·+ [ p M: phosphorylated angiotensin III derivative; terpy: 2,2':6',2''-terpyridine; salen: N, N '-ethylenebis(salicylideneiminato)]. Subsequent CID of the phosphorylated peptide radical cations ( p M·+) revealed fascinating gas-phase radical chemistry, yielding (1) charge-directed b- and y-type product ions, (2) radical-driven product ions through cleavages of peptide backbones and side chains, and (3) different degrees of formation of [M - H3PO4]·+ species through phosphate ester bond cleavage. The CID spectra of the p M·+ species and their non-phosphorylated analogues featured fragment ions of similar sequence, suggesting that the phosphoryl group did not play a significant role in the fragmentation of the peptide backbone or side chain. The extent of neutral H3PO4 loss was influenced by the peptide sequence and the initial sites of the charge and radical. A preliminary density functional theory study, at the B3LYP 6-311++G(d,p) level of theory, of the neutral loss of H3PO4 from a prototypical model— N-acetylphosphorylserine methylamide—revealed several factors governing the elimination of neutral phosphoryl groups through charge- and radical-induced mechanisms.

  17. Improving the Selectivity of the Phosphoric Acid β-Elimination on a Biotinylated Phosphopeptide

    NASA Astrophysics Data System (ADS)

    Matheron, Lucrèce; Clavier, Séverine; Diebate, Oumar; Karoyan, Philippe; Bolbach, Gérard; Guianvarc'h, Dominique; Sachon, Emmanuelle

    2012-11-01

    This study aims at improving the MALDI-TOF detection of a phosphorylated peptide containing a cysteine residue by β-elimination of H3PO4 hardly enriched by classical methods. The experimental conditions were optimized on this phosphopeptide (biot-pAdd) and its nonphosphorylated counterpart (biot-Add). The major side-reactions were H2S elimination on the cysteine residues and H2O elimination on the non phosphorylated serine residue of biot-Add. The former dilutes the MALDI-TOF signal for the desired species. The latter gives a product similar to what is obtained by H3PO4 elimination and should prompt to caution when working with a mixture between phosphorylated and non phosphorylated peptides. Modifications on the solvent, the reaction temperature and time, the nature, and concentration of the base were made. Major improvement of the selectivity of the reaction was observed in 30 % ACN, at room temperature for 4 h. However, these optimizations are specific to these sequences and should be performed anew for different peptides. The selectivity of the reaction towards H3PO4 elimination is improved, but the persistence of side-reactions renders a previous sample fractionation necessary. In these optimized conditions, the ionization enhancement is 3-fold and the detection limits for biot-pAdd are similar to biot-Add (100 fmol).

  18. Formation and dissociation of phosphorylated peptide radical cations.

    PubMed

    Kong, Ricky P W; Quan, Quan; Hao, Qiang; Lai, Cheuk-Kuen; Siu, Chi-Kit; Chu, Ivan K

    2012-12-01

    In this study, we generated phosphoserine- and phosphothreonine-containing peptide radical cations through low-energy collision-induced dissociation (CID) of the ternary metal-ligand phosphorylated peptide complexes [Cu(II)(terpy)(p)M](·2+) and [Co(III)(salen)(p)M](·+) [(p)M: phosphorylated angiotensin III derivative; terpy: 2,2':6',2''-terpyridine; salen: N,N'-ethylenebis(salicylideneiminato)]. Subsequent CID of the phosphorylated peptide radical cations ((p)M(·+)) revealed fascinating gas-phase radical chemistry, yielding (1) charge-directed b- and y-type product ions, (2) radical-driven product ions through cleavages of peptide backbones and side chains, and (3) different degrees of formation of [M - H(3)PO(4)](·+) species through phosphate ester bond cleavage. The CID spectra of the (p)M(·+) species and their non-phosphorylated analogues featured fragment ions of similar sequence, suggesting that the phosphoryl group did not play a significant role in the fragmentation of the peptide backbone or side chain. The extent of neutral H(3)PO(4) loss was influenced by the peptide sequence and the initial sites of the charge and radical. A preliminary density functional theory study, at the B3LYP 6-311++G(d,p) level of theory, of the neutral loss of H(3)PO(4) from a prototypical model--N-acetylphosphorylserine methylamide--revealed several factors governing the elimination of neutral phosphoryl groups through charge- and radical-induced mechanisms. PMID:22968907

  19. 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.

  20. 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.

  1. Release of monomeric sugars from Miscanthus sinensis by microwave-assisted ammonia and phosphoric acid treatments.

    PubMed

    Boonmanumsin, P; Treeboobpha, S; Jeamjumnunja, K; Luengnaruemitchai, A; Chaisuwan, T; Wongkasemjit, S

    2012-01-01

    Microwave-assisted ammonium hydroxide (NH4OH) followed by phosphoric acid (H3PO4) treatments were used to release monomeric sugars from Miscanthus sinensis grown in Cha-Chueng-Sao province, Thailand. Treatment with 1.0% (w/v) NH4OH, 15:1 liquid-to-solid ratio (LSR) at 120 °C temperature for 15 min liberated 2.9 g of monomeric sugars per 100 g of dried biomass, whereas the corresponding yield for a treatment with 1.78% v/v H3PO4, 15:1 LSR at 140 °C for 30 min was 62.3 g/100 g. The two-stage pretreatment, treatment with NH4OH at 120 °C temperature for 15 min followed by treatment with H3PO4 at 140 °C for 30 min, impressively provided the highest total monomeric sugar yield of 71.6 g/100 g dried biomass. PMID:22040909

  2. Effect of chemical etching on the morphology of anodic aluminum oxides in the two-step anodization process

    NASA Astrophysics Data System (ADS)

    Erdogan, Pembe; Yuksel, Behiye; Birol, Yucel

    2012-03-01

    Morphological features of the anodic aluminum oxide (AAO) templates fabricated by electrochemical oxidation under different chemical etching conditions were investigated. The chemical etching treatment had a paramount impact on the morphological features of the AAO templates produced with the two-step anodization process. Increasing the etching treatment time was found to be favourable, provided that the ratio of the etching treatment time to that of anodization must be at least one half. Etching solutions based merely on H3PO4 fail to remove the aluminum oxides from the first anodization step. The addition of as much as 2% CrO3 offers a marked improvement in the AAO pore features. Increasing the H3PO4 concentration in H3PO4-CrO3 mixtures improves the pore features while an increase in the CrO3 concentration has no effect. The temperature of the etching solution also affects the morphology of AAO pores remarkably. An etching solution temperature of 55 °C is the optimum.

  3. Antimicrobial effect of calcium hydroxide as an intracanal medicament in root canal treatment: a literature review - Part II. in vivo studies

    PubMed Central

    2015-01-01

    The first part of this study reviewed the characteristics of calcium hydroxide (Ca(OH)2) and summarized the results of in vitro studies related to its antimicrobial effects. The second part of this review covers in vivo studies including human clinical studies and animal studies. The use of Ca(OH)2 as an intracanal medicament represented better histological results in animal studies. However, human clinical studies showed limited antimicrobial effects that microorganisms were reduced but not eliminated through the treatment, and that some species had resistance to Ca(OH)2. Most of clinical outcome studies supported that there is no improvement in healing of periapical lesions when Ca(OH)2 was applied between appointments. Further studies are required for the antimicrobial effects of Ca(OH)2, and search for the ideal material and technique to completely clean infected root canals should be continued. PMID:25984470

  4. In vitro diffusion of hydroxyl ions through root dentine from various calcium hydroxide medicaments.

    PubMed

    Sevimay, S; Kalayci, A; Yilmaz, S

    2003-10-01

    The purpose of this study was to determine diffusion of hydroxyl ions through dentine from different calcium hydroxide [Ca(OH)2] medicaments. Forty-five single-rooted teeth were instrumented and cavities (3 mm in diameter and 1 mm in depth) were prepared on the facial surface of each root. After smear layer was removed with 17% EDTA all surfaces of roots, except cavities, were coated with nail polish. Teeth were randomly divided into four experimental groups (each 10 samples) and a control group (five samples). They were filled with: group 1, Ca(OH)2 and distilled water mixture; group 2, TempCanal; group 3, Calasept; and group 4, Ca(OH)2 plus point. Control group, in which nothing was applied to the canals. All samples were immersed in distilled water maintained at 37 degrees C. pH values were measured at 1 h, 2 h, 3 h, 24 h, 48 h, 72 h, 4 days, 5 days, 6 days, 7 days and 14 days. Ca(OH)2-distilled water mixture and TempCanal showed highest pH values at 24 h. Calasept, Ca(OH)2 plus point and control showed highest pH values at 3 h. Time intervals after 24 h, Ca(OH)2-distilled water mixture, TempCanal and Calasept showed higher pH values than Ca(OH)2 plus point, with a statistically significant difference (P<0.05). The pH value of Ca(OH)2 plus point was lower than the values of other materials after 3 h. This study indicates that non-setting Ca(OH)2 based materials have an effective release of hydroxyl ions compared with Ca(OH)2 plus point. PMID:12974867

  5. The efficacy of the self-adjusting file and ProTaper for removal of calcium hydroxide from root canals

    PubMed Central

    FARIA, Gisele; KUGA, Milton Carlos; RUY, Alessandra Camila; ARANDA-GARCIA, Arturo Javier; BONETTI-FILHO, Idomeo; GUERREIRO-TANOMARU, Juliane Maria; LEONARDO, Renato Toledo

    2013-01-01

    Objective The goal of this study was to evaluate the efficacy of the Self-Adjusting File (SAF) and ProTaper for removing calcium hydroxide [Ca(OH)2] from root canals. Material and Methods Thirty-six human mandibular incisors were instrumented with the ProTaper system up to instrument F2 and filled with a Ca(OH)2-based dressing. After 7 days, specimens were distributed in two groups (n=15) according to the method of Ca(OH)2 removal. Group I (SAF) was irrigated with 5 mL of NaOCl and SAF was used for 30 seconds under constant irrigation with 5 mL of NaOCl using the Vatea irrigation device, followed by irrigation with 3 mL of EDTA and 5 mL of NaOCl. Group II (ProTaper) was irrigated with 5 mL of NaOCl, the F2 instrument was used for 30 seconds, followed by irrigation with 5 mL of NaOCl, 3 mL of EDTA, and 5 mL of NaOCl. In 3 teeth Ca(OH)2 was not removed (positive control) and in 3 teeth canals were not filled with Ca(OH)2 (negative control). Teeth were sectioned and prepared for the scanning electron microscopy. The amounts of residual Ca(OH)2 were evaluated in the middle and apical thirds using a 5-score system. Results None of the techniques completely removed the Ca(OH)2 dressing. No difference was observed between SAF and ProTaper in removing Ca(OH)2 in the middle (P=0.11) and the apical (P=0.23) thirds. Conclusion The SAF system showed similar efficacy to rotary instrument for removal of Ca(OH)2 from mandibular incisor root canals. PMID:24037074

  6. 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.

  7. Large-Scale Examination of Factors Influencing Phosphopeptide Neutral Loss during Collision Induced Dissociation

    NASA Astrophysics Data System (ADS)

    Brown, Robert; Stuart, Scott S.; Houel, Stephane; Ahn, Natalie G.; Old, William M.

    2015-07-01

    Collision-induced dissociation (CID) remains the predominant mass spectrometry-based method for identifying phosphorylation sites in complex mixtures. Unfortunately, the gas-phase reactivity of phosphoester bonds results in MS/MS spectra dominated by phosphoric acid (H3PO4) neutral loss events, suppressing informative peptide backbone cleavages. To understand the major drivers of H3PO4 neutral loss, we performed robust nonparametric statistical analysis of local and distal sequence effects on the magnitude and variability of neutral loss, using a collection of over 35,000 unique phosphopeptide MS/MS spectra. In contrast to peptide amide dissociation pathways, which are strongly influenced by adjacent amino acid side chains, we find that neutral loss of H3PO4 is affected by both proximal and distal sites, most notably basic residues and the peptide N-terminal primary amine. Previous studies have suggested that protonated basic residues catalyze neutral loss through direct interactions with the phosphate. In contrast, we find that nearby basic groups decrease neutral loss regardless of mobility class, an effect only seen by stratifying spectra by charge-mobility. The most inhibitory bases are those immediately N-terminal to the phosphate, presumably because of steric hindrances in catalyzing neutral loss. Further evidence of steric effects is shown by the presence of proline, which can dramatically reduce the presence of neutral loss when between the phosphate and a possible charge donor. In mobile proton spectra, the N-terminus is the strongest predictor of high neutral loss, with proximity to the N-terminus essential for peptides to exhibit the highest levels of neutral loss.

  8. 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.

  9. Wetting ability of an acetone/based etch&rinse adhesive after NaOCl-treatment

    PubMed Central

    Aguilera, Fátima S.; Osorio, Raquel; Osorio, Estrella; Moura, Pedro

    2012-01-01

    Objectives: to evaluate the effect of sodium hypochlorite (NaOCl) treatment on surface dentin roughness (Ra) and contact angle (CA) when using Prime&Bond NT adhesive (PB NT). Study Design: Extracted human third molars were sectioned to expose flat, superficial and deep dentin surfaces. CA and Ra were measured (1) before and (2) after 35% H3PO4 etching, and (3) H3PO4 etching + 5% NaOCl treated for 2 minutes before the application of PB NT. CA was measured by the Axisymmetric Drop Shape Analysis Technique using distilled and deionized water and PB NT. Roughness was evaluated with a profilometer, twelve radial measurements were performed in each treatment surface. Data were analyzed with two-way ANOVA and Newman-Keuls multiple comparison test procedures. Results: CA values decreased after acid etching and even more after NaOCl treatment on deep dentin when water was tested. With resin, there were not differences on CA results after H3PO4 neither after NaOCl treatment, in both dentin surfaces. Etching and NaOCl treatment resulted in surface roughness increase. Conclusions: In spite of the higher roughness after NaOCl treatment on superficial and deep dentin, the use of 5% NaOCl for 2 min after dentin demineralization when PB NT was employed did not improved the wettability of dentin, probably due to nanofiller content and/or hydrogen-bonding interactions with residues of the organic matrix on collagen-depleted dentin. Key words:Sodium hypochlorite, contact angle, roughness, Prime&Bond NT, superficial dentin, deep dentin. PMID:22322490

  10. Bonding efficacy of an acetone/based etch-and-rinse adhesive after dentin deproteinization

    PubMed Central

    Aguilera, Fátima S.; Osorio, Raquel; Osorio, Estrella; Moura, Pedro

    2012-01-01

    Objectives: to evaluate the effect of sodium hypochlorite (NaOCl) treatment on dentin bonding by means of shear bond strength (SBS) measurements when using Prime&Bond NT (PB NT) adhesive. Ultrastructure of the interfaces was examined by scanning electron microscopy (SEM). Study design: Extracted human third molars were sectioned and ground to expose flat surfaces of superficial or deep dentin. Specimens were randomly assigned to two equal groups, and bonded as follows: (1) according to the manufacturers’ directions, after 35% H3PO4 etching, (2) 5% NaOCl treated for 2 minutes, after 35% H3PO4 etching. Each sample was embedded in a Watanabe shear test assembly for a single plane lap shear. After PB NT bonding, specimens were stored in water for 24 h at 37ºC and thermocycled (500x). Samples were tested in shear to failure using a universal testing machine at 0.75 mm/min. Data were analyzed with ANOVA and Newman-Keuls multiple comparison test procedures. Two samples of each group were randomly selected to investigate the morphologic aspect of the resin/dentin interface with SEM. Results: After etching and after aqueous sodium hypochlorite (NaOClaq) application, SBS values were similar on superficial than deep dentin (p>0.05). SEM findings shows for H3PO4 etching conditioned samples a detectable hybrid layer and long resin tags; for NaOCl treated specimens, it may be observed a non apparent hybrid layer, and the adhesive contact directly with the neck of the cylindrical resin tags. Conclusions: The use of 5% NaOCl for 2 min after dentin demineralization when PB NT was employed did not improve the bond strength to dentin, probably due to nanofiller content and/or oxidative changes on collagen-depleted dentin. Key words:Sodium hypochlorite, shear bond strength, SEM, Prime&Bond NT, superficial dentin, deep dentin. PMID:22322501

  11. Critical exponents for solvent extraction resolved using SAXS.

    PubMed

    Ellis, Ross J

    2014-01-01

    The solvent extraction of an ionizable solute (H3PO4) from water into a water-in-oil microemulsion, and subsequent organic phase splitting (known as third phase formation), has been recast as a critical phenomenon by linking system structure to solute concentration via a critical exponent. The transuranic extraction (TRUEX) system was investigated by extracting increasing concentrations of H3PO4 into a microemulsion--consisting of two extractant amphiphiles (CMPO and TBP) and water in n-dodecane--and taking small-angle X-ray scattering (SAXS) measurements from the resulting solutions. The H3PO4 concentration at which phase splitting occurred was defined as the critical concentration (XC), and this was related to the precritical concentrations (X) by the reduced parameter ε = (X(C) - X)/X(C). The scattering intensity at the zero angle I(0), relating to the interaction between reverse micellar aggregates, conformed to the relation I(0) = I0ε(-γ), with critical exponent γ = 2.20. To check γ, SAXS measurements were taken from the organic phase in situ with variable temperature through the point at which third phase formation initiates (the critical temperature), giving I(0) = I0t(-γ), where t = (T - T(C))/T(C) and T(C) and T are the critical and precritical temperatures, with critical exponent γ = 2.55. These γ values suggest third phase formation is a universal phenomenon manifest from a critical double point. Thus, solvent extraction is reduced to its fundamental physical roots where the system is not defined by detailed analysis of metrical properties but by linking the fundamental order to thermodynamic parameters via an exponent, working toward a more predictive understanding of third phase formation. PMID:24328275

  12. 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 (α=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

  13. The influence of preservation method and time on the delta13C value of dissolved inorganic carbon in water samples.

    PubMed

    Taipale, Sami J; Sonninen, Eloni

    2009-08-30

    The precise delta(13)C value of dissolved inorganic carbon (DIC) is important for various types of ecological studies. Without a preservation agent, microbial degradation of organic compounds continues in water samples and the delta(13)C value of DIC will become more depleted with time. HgCl(2) or acidification is often used to prevent microbial activity in water samples collected for carbon isotope ratio analyses of DIC. Mercury compounds are toxic and result in waste disposal problems. Other inhibiting agents or preservation methods are therefore needed. Two possible solutions are to use copper sulphate (CuSO(4)) as a preservative agent or to acidify water samples with phosphoric acid (H(3)PO(4)) within 12 mL measurement Exetainers (septum-capped vials). We prepared a set of lake water samples in three types of vials: glass vials with silicone/PTFE septa, high-density polyethylene vials (HD-PE, scintillation vials) and Exetainers (12 mL) with butyl rubber septa. Samples in glass and PE vials were preserved with and without CuSO(4), whereas lake water was injected into the Exetainer and acidified with H(3)PO(4). Isotope ratios were measured in two laboratories over 6 months. The delta(13)C values of DIC systematically increased with storage time for samples preserved in glass and PE vials with and without CuSO(4). A strong correlation between a decrease of CO(2) concentration and an increase in DIC delta(13)C values was found. The delta(13)C values and DIC concentrations were stable for 6 months in acidified samples stored in Exetainers with butyl rubber septa. Therefore, we conclude that the best method for up to 6 months of storage is to inject samples in the field into butyl rubber septum capped Exetainers containing H(3)PO(4), thereby avoiding the use of preservatives. PMID:19603464

  14. 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

  15. Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

    NASA Astrophysics Data System (ADS)

    Hlaing, Nwe Ni; Vignesh, K.; Sreekantan, Srimala; Pung, Swee-Yong; Hinode, Hirofumi; Kurniawan, Winarto; Othman, Radzali; Thant, Aye Aye; Mohamed, Abdul Rahman; Salim, Chris

    2016-02-01

    Calcium hydroxide (Ca(OH)2) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH)2 based adsorbents for carbon dioxide (CO2) capture. The effect of CTAB concentration (0.2-0.8 M) on the structure, morphology and CO2 adsorption performance of Ca(OH)2 was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG-DTA) techniques. The phase purity, crystallite size, Brunauer-Emmett-Teller (BET) surface area and CO2 adsorption performance of Ca(OH)2 precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH)2 phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH)2 precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

  16. Alkali-treated konjac glucomannan film as a novel wound dressing.

    PubMed

    Huang, Yi-Cheng; Chu, Hao-Wen; Huang, Chih-Ching; Wu, Wen-Ching; Tsai, Jenn-Shou

    2015-03-01

    To investigate the potential medical application of konjac glucomannan (KGM), we treated KGM film with potassium hydroxide (KOH) or calcium hydroxide (Ca(OH)2), and evaluated its use as a wound dressing. The Ca(OH)2-treated KGM (Ca(OH)2-KGM) film exhibited more favorable properties of swelling, tensile strength, and elongation compared with the KOH-treated KGM (KOH-KGM) film, and also had a suitable water vapor transmission rate. Results from in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay further indicated the biocompatibility of the Ca(OH)2-KGM film with L929 fibroblast cells and HaCaT keratinocyte cells. The Ca(OH)2-KGM film inhibited the absorption and activation of platelets, and effectively promoted wound contractility in vivo, particularly at an early healing stage. Histological examination revealed considerably collagen secretion and advanced development of granulation tissue and epithelial coverage by Days 7 and 14 postsurgery in wounds treated with Ca(OH)2-KGM film. Our study results indicate the potential use of alkali-treated KGM film as a novel wound dressing. PMID:25498700

  17. Chlorpheniramine dissolution and relative urinary excretion from commercial products.

    PubMed

    Hsu, H Y; Ayres, J W

    1989-10-01

    Dissolution profiles were determined for seven commercially available nonprescription solid dosage forms containing chlorpheniramine (four sustained release and three immediate release). An in vitro pH change method used to simulate GI transit produced dissolution profiles for some similarly labeled products which were significantly nonequivalent. One product failed to release its chlorpheniramine even when ground in a mortar and pestle in HCl solution, but did release drug in H3PO4 solution. A small (four subjects) relative bioavailability study based on average cumulative excretion of intact drug in urine gave results in parallel with substantially nonequivalent dissolution data for three products. PMID:2600791

  18. Synthesis of polyacrylic-acid-based thermochromic polymers

    NASA Astrophysics Data System (ADS)

    Srivastava, Jyoti; Alam, Sarfaraz; Mathur, G. N.

    2003-10-01

    Smart materials respond to environmental stimuli with particular changes in some variables (for example temperature, pressure and electric field etc), for that reason they are often called responsive materials. In the present work, we have synthesized thermochromic polymer based on poly acrylic acid cobalt chloride (CoCl2) and phosphoric acid (H3PO4) that visually and reversibly changes color in the temperature range (70 - 130°C). These thermochromic materials can be used as visual sensors of temperature. Thermochromic polymers are based on polyacrylic acid and CoCl2 complex.

  19. Design of a cell for electrode kinetic investigations of fuel cell reactions

    NASA Astrophysics Data System (ADS)

    Olender, H.; McBreen, J.; Ogrady, W. E.; Srinivasan, S.; Kordesch, K. V.

    1982-01-01

    Two designs of a cell for investigation of electrode kinetics of fuel cell reactions in acid media are described. The cells are suitable for evaluation of carbon supported platinum electrodes under conditions simulating a phosphoric acid fuel cell environment at elevated temperature and pressure. The usefulness of this for obtaining fuel cell performance, overpotential-current density relation, and in situ platinum surface area measurements in 98.6% H3PO4 at 150 C is demonstrated. The cell design is also ideal for the electrochemical determination of cross migration of oxygen through the matrix at 180 C.

  20. Metal immobilization and phosphorus leaching after stabilization of pyrite ash contaminated soil by phosphate amendments.

    PubMed

    Zupan?i?, Marija; Lavri?, Simona; Bukovec, Peter

    2012-02-01

    In this study we would like to show the importance of a holistic approach to evaluation of chemical stabilization using phosphate amendments. An extensive evaluation of metal stabilization in contaminated soil and an evaluation of the leaching of phosphorus induced after treatment were performed. The soil was highly contaminated with Cu (2894 mg kg(-1)), Zn (3884 mg kg(-1)), As (247 mg kg(-1)), Cd (12.6 mg kg(-1)) and Pb (3154 mg kg(-1)). To immobilize the metals, mixtures of soil with phosphate (from H(3)PO(4) and hydroxyapatite (HA) with varying ratios) were prepared with a constant Pb : P molar ratio of 1: 10. The acetic acid extractable concentration of Pb in the mixture with the highest amount of added phosphoric acid (n(H(3)PO(4)) : n(HA) = 3 : 1) was reduced to 1.9% (0.62 mg L(-1)) of the extractable Pb concentration in the untreated soil, but the content of water extractable phosphorus in the samples increased from 0.04 mg L(-1) in the untreated soil sample up to 14.3 mg L(-1) in the same n(H(3)PO(4)) : n(HA) = 3 : 1 mixture. The high increase in arsenic mobility was also observed after phosphate addition. The PBET test showed phosphate induced reduction in Pb bioavailability. In attempting to stabilize Pb in the soil with the minimum treatment-induced leaching of phosphorus, it was found that a mixture of soil with phosphate addition in the molar ratio of H(3)PO(4) : HA of 0.75 : 1 showed the most promising results, with an acetic acid extractable Pb concentration of 1.35 mg L(-1) and a water extractable phosphorus concentration of 1.76 mg L(-1). The time-dependent leaching characteristics of metals and phosphorus for this mixture were evaluated by a column experiment, where irrigation of the soil mixture with the average annual amount of precipitation in Slovenia (1000 mm) was simulated. The phosphorus concentration in the leachates decreased from 2.60 mg L(-1) at the beginning of irrigation to 1.00 mg L(-1) at the end. PMID:22240857

  1. A novel approach for stabilizing fresh urine by calcium hydroxide addition

    PubMed Central

    Randall, Dyllon G.; Krähenbühl, Manuel; Köpping, Isabell; Larsen, Tove A.; Udert, Kai M.

    2016-01-01

    In this study, we investigated the prevention of enzymatic urea hydrolysis in fresh urine by increasing the pH with calcium hydroxide (Ca(OH)2) powder. The amount of Ca(OH)2 dissolving in fresh urine depends significantly on the composition of the urine. The different urine compositions used in our simulations showed that between 4.3 and 5.8 g Ca(OH)2 dissolved in 1 L of urine at 25 °C. At this temperature, the pH at saturation is 12.5 and is far above the pH of 11, which we identified as the upper limit for enzymatic urea hydrolysis. However, temperature has a strong effect on the saturation pH, with higher values being achieved at lower temperatures. Based on our results, we recommend a dosage of 10 g Ca(OH)2 L−1 of fresh urine to ensure solid Ca(OH)2 always remains in the urine reactor which ensures sufficiently high pH values. Besides providing sufficient Ca(OH)2, the temperature has to be kept in a certain range to prevent chemical urea hydrolysis. At temperatures below 14 °C, the saturation pH is higher than 13, which favors chemical urea hydrolysis. We chose a precautionary upper temperature of 40 °C because the rate of chemical urea hydrolysis increases at higher temperatures but this should be confirmed with kinetic studies. By considering the boundaries for pH and temperature developed in this study, urine can be stabilized effectively with Ca(OH)2 thereby simplifying later treatment processes or making direct use easier. PMID:27055084

  2. A novel approach for stabilizing fresh urine by calcium hydroxide addition.

    PubMed

    Randall, Dyllon G; Krähenbühl, Manuel; Köpping, Isabell; Larsen, Tove A; Udert, Kai M

    2016-05-15

    In this study, we investigated the prevention of enzymatic urea hydrolysis in fresh urine by increasing the pH with calcium hydroxide (Ca(OH)2) powder. The amount of Ca(OH)2 dissolving in fresh urine depends significantly on the composition of the urine. The different urine compositions used in our simulations showed that between 4.3 and 5.8 g Ca(OH)2 dissolved in 1 L of urine at 25 °C. At this temperature, the pH at saturation is 12.5 and is far above the pH of 11, which we identified as the upper limit for enzymatic urea hydrolysis. However, temperature has a strong effect on the saturation pH, with higher values being achieved at lower temperatures. Based on our results, we recommend a dosage of 10 g Ca(OH)2 L(-1) of fresh urine to ensure solid Ca(OH)2 always remains in the urine reactor which ensures sufficiently high pH values. Besides providing sufficient Ca(OH)2, the temperature has to be kept in a certain range to prevent chemical urea hydrolysis. At temperatures below 14 °C, the saturation pH is higher than 13, which favors chemical urea hydrolysis. We chose a precautionary upper temperature of 40 °C because the rate of chemical urea hydrolysis increases at higher temperatures but this should be confirmed with kinetic studies. By considering the boundaries for pH and temperature developed in this study, urine can be stabilized effectively with Ca(OH)2 thereby simplifying later treatment processes or making direct use easier. PMID:27055084

  3. 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

  4. Hydrolysis of sorghum straw using phosphoric acid: evaluation of furfural production.

    PubMed

    Vázquez, Manuel; Oliva, Martha; Téllez-Luis, Simón J; Ramírez, José A

    2007-11-01

    Sorghum straw is a waste that has been studied scarcely. The main application is its use as raw material for xylose production. Xylose is a hemicellulosic sugar mainly used for its bioconversion toward xylitol. An alternative use could be its conversion toward furfural. The objective of this work was to study the furfural production by hydrolysis of sorghum straw with phosphoric acid at 134 degrees C. Several concentrations of H(3)PO(4) in the range 2-6% and reaction time (range 0-300 min) were evaluated. Kinetic parameters of mathematical models for predicting the concentration of xylose, glucose, arabinose, acetic acid and furfural in the hydrolysates were found. Optimal conditions for furfural production by acid hydrolysis were 6% H(3)PO(4) at 134 degrees C for 300 min, which yielded a solution with 13.7 g furfural/L, 4.0 g xylose/L, 2.9 g glucose/L, 1.1g arabinose/L and 1.2g acetic acid/L. The furfural yield of the process was 0.1336 g furfural/g initial dry matter was obtained. The results confirmed that sorghum straw can be used for furfural production when it is hydrolyzed using phosphoric acid. PMID:17145181

  5. Digital image-based titrations.

    PubMed

    Gaiao, Edvaldo da Nobrega; Martins, Valdomiro Lacerda; Lyra, Wellington da Silva; de Almeida, Luciano Farias; da Silva, Edvan Cirino; Araújo, Mário César Ugulino

    2006-06-16

    The exploitation of digital images obtained from a CCD camera (WebCam) as a novel instrumental detection technique for titration is proposed for the first time. Named of digital image-based (DIB) titration, it also requires, as a traditional titration (for example, spectrophotometric, potentiometric, conductimetric), a discontinuity in titration curves where there is an end point, which is associated to the chemical equivalence condition. The monitored signal in the DIB titration is a RGB-based value that is calculated, for each digital image, by using a proposed procedure based on the red, green, and blue colour system. The DIB titration was applied to determine HCl and H3PO4 in aqueous solutions and total alkalinity in mineral and tap waters. Its results were compared to the spectrophotometric (SPEC) titration and, by applying the paired t-test, no statistic difference between the results of both methods was verified at the 95% confidence level. Identical standard deviations were obtained by both titrations in the determinations of HCl and H3PO4, with a slightly better precision for DIB titration in the determinations of total alkalinity. The DIB titration shows to be an efficient and promising tool for quantitative chemical analysis and, as it employs an inexpensive device (WebCam) as analytical detector, it offers an economically viable alternative to titrations that need instrumental detection. PMID:17723410

  6. Plasmonic enhancement of photoluminescence from aluminium nitride

    NASA Astrophysics Data System (ADS)

    Flynn, Chris; Stewart, Matthew

    2016-03-01

    Aluminium nitride (AlN) films were grown on c-plane sapphire wafers by molecular beam epitaxy (MBE) under aluminium-rich conditions. The excess aluminium (Al) accumulated on the surface of the films as micro-scale droplets 1-10 μm in size, and as Al nanoparticles with diameters in the range 10-110 nm. Photoluminescence (PL) measurements were performed on the AlN samples using a 193 nm Excimer laser as the excitation source. Prior to PL measurements the wafers were cleaved in half. One half of each wafer was submitted to a 10 min treatment in H3PO4 heated to 70 °C to remove the excess Al from the film surface. The remaining half was left in the as-deposited condition. The mean intensities of the near-band-edge PL peaks of the as-deposited samples were 2.0-3.4 times higher compared to the samples subjected to the H3PO4 Al-removal treatment. This observation motivated calculations to determine the optimal Al surface nanosphere size for plasmonic enhancement of PL from AlN. The PL enhancement was found to peak for an Al nanosphere radius of 15 nm, which is within the range of the experimentally-observed Al nanoparticle sizes.

  7. Catalytic fast pyrolysis of cellulose and biomass to produce levoglucosenone using magnetic SO4(2-)/TiO2-Fe3O4.

    PubMed

    Lu, Qiang; Ye, Xiao-ning; Zhang, Zhi-bo; Dong, Chang-qing; Zhang, Ying

    2014-11-01

    Magnetic superacid (SO4(2-)/TiO2-Fe3O4) was prepared for catalytic fast pyrolysis of cellulose and poplar wood to produce levoglucosenone (LGO). Its catalytic activity was evaluated via pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments, and compared with the non-magnetic SO4(2-)/TiO2, phosphoric acid (H3PO4) and sulfur acid (H2SO4) catalysts. Moreover, the LGO yield was quantitatively determined. The results indicated that the magnetic SO4(2-)/TiO2-Fe3O4 was effective to selectively produce LGO from both cellulose and poplar wood. Its catalytic capability was a little better than the non-magnetic SO4(2-)/TiO2 and H3PO4, and much better than the H2SO4. The maximal LGO yields from both cellulose and poplar wood were obtained at 300 °C with the feedstock/catalyst ratio of 1/1, reaching as high as 15.43 wt% from cellulose and 7.06 wt% from poplar wood, respectively. PMID:25173471

  8. The correlation between cellulose allomorphs (I and II) and conversion after removal of hemicellulose and lignin of lignocellulose.

    PubMed

    Song, Yanliang; Zhang, Jingzhi; Zhang, Xu; Tan, Tianwei

    2015-10-01

    H2SO4, NaOH and H3PO4 were applied to decompose lignocellulose samples (giant reeds, pennisetum and cotton stalks) to investigate the correlation between cellulose allomorphs (cellulose I and II) and conversion of cellulose. The effect of removal of hemicellulose and lignin on the surface morphology, crystallinity index (CrI), cellulose allomorphs (cellulose I and II), and enzymatic hydrolysis under different pretreatments was also studied. CrI caused by H3PO4 pretreatment reached 11.19%, 24.93% and 8.15% for the three samples, respectively. Corn stalk showed highest conversion of cellulose among three samples, irrespective of the pretreatment used. This accounted for the widely use of corn stalk as the renewable crop substrate to synthesize biofuels like ethanol. CrI of cellulose I (CrI-I) negatively affects cellulose conversion but CrI of cellulose II (CrI-II) positively affects cellulose conversion. It contributes to make the strategy to transform cellulose I to cellulose II and enhancing enzymatic hydrolysis of lignocellulose. PMID:26133473

  9. 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.

  10. 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.

  11. A simplified etching technique to improve the adhesion of fiber post

    PubMed Central

    Veeramachaneni, Chandrasekhar; Morisetty, Pradeep Kumar; Rao, Saggurti Anitha; Tummala, Muralidhar

    2014-01-01

    PURPOSE Numerous methods were used to etch the fiber posts to improve its bonding to root canal dentin. Our aim was to evaluate the efficacy of 37% phosphoric acid in etching fiber posts in comparison with 24% hydrogen peroxide. MATERIALS AND METHODS Ninety human maxillary central incisors were taken and post space preparation was done. Ninety fiber posts were taken and divided into three groups (n=30) based on the surface treatment they received (H3PO4, H2O2, distilled water) and each group was further divided (n=10) based on the time period of application (15 seconds, 30 seconds, 60 seconds). All the posts were luted into canals using Rely X UniCem-2. Each tooth was then sectioned into six slices and subjected to push out test. Data obtained was subjected to statistical analysis at P<.05. The surface topography was evaluated using scanning electron microscopy. RESULTS Highest bond strength values were noted in 15 seconds etched phosphoric acid group and 60 seconds etched hydrogen peroxide group with no significant difference between two groups. Surface topography revealed complete epoxy layer removal with no damage to its structural integrity in those groups. CONCLUSION H3PO4 etching for a period of 15 seconds is an effective alternative in improving the adhesion of fiber post to root dentin. PMID:25177473

  12. Blue luminescence in porous anodic alumina films

    NASA Astrophysics Data System (ADS)

    Li, Zhaojian; Huang, Kelong

    2007-05-01

    We have investigated the luminescence property of anodic alumina membranes (AAM) with ordered nanopore arrays prepared by electrochemically anodizing aluminium in oxalic acid, sulfuric acid and phosphoric acid solutions. The photoluminescence (PL) intensity of AAM prepared in C2H2O4 is much higher than that of AAMs prepared in H2SO4 and H3PO4. The PL spectra obtained show that there are two optical centres for the AAMs prepared in H2SO4 and H3PO4, of which the first originates from the F+ centres, and the second is associated with the F centres. It is found that the oxalic impurities incorporated in the AAMs should have important influences on the optical properties of AAM prepared in C2H2O4. The blue emission band in the AAM prepared in C2H2O4 originates from the coactions of the F+ centres, the F centre and the luminescent centres transformed from oxalic impurities.

  13. 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

  14. Printed all-solid flexible microsupercapacitors: towards the general route for high energy storage devices

    NASA Astrophysics Data System (ADS)

    Wang, Ye; Shi, Yumeng; Zhao, Cheng Xi; Wong, Jen It; Sun, Xiao Wei; Yang, Hui Ying

    2014-03-01

    A novel method for fabricating all-solid flexible microsupercapacitors (MSCs) was proposed and developed by utilizing screen printing technology. A typical printed MSC is composed of a printed Ag electrode, MnO2/onion-like carbon (MnO2/OLC) as active material and a polyvinyl alcohol:H3PO4 (PVA:H3PO4) as solid electrolyte. A capacity of 7.04 mF cm-2 was achieved for the screen printed MnO2/OLC MSCs at a current density of 20 μA cm-2. It also showed an excellent cycling stability, with 80% retention of the specific capacity after 1000 cycles. The printed all-solid flexible MSCs exhibited remarkably high mechanical flexibility when the devices were bent to a radius of 3.5 mm. In addition, all-solid MSCs were successfully demonstrated by screen printing technique on various substrates, such as silicon, glass and conventional printing paper. Moreover, the screen printing technique can be extended to other active materials, such as OLC and carbon nanotubes. This method provides a general route for printable all-solid flexible MSCs, which is compatible with the roll-to-roll process for various high performance active materials.

  15. Comparison of homogeneous and heterogeneous acid promoters in single-step aqueous-organosolv fractionation of eucalyptus wood chips.

    PubMed

    Klamrassamee, Thepparat; Champreda, Verawat; Reunglek, Vasimon; Laosiripojana, Navadol

    2013-11-01

    Fractionation of lignocellulosic biomass is a primary step for converting multi-structure biomass to biofuels and other industrial products in integrated biorefinery processes. Here, the effects of homogeneous and heterogeneous acid promoters (HNO3-, HCl-, H2SO4-, and H3PO4-activated carbons) on Clean Fractionation (CF), a single-step aqueous-organosolv fractionation, of eucalyptus wood chips was studied and optimised. The optimised process contained 16.7% w/v biomass in a ternary mixture of methyl isobutyl ketone:methanol:water (25:42:33) with 5% AC-H3PO4 and incubated at 180 °C for 60 min. Under these conditions, 41.2 wt.% cellulose was obtained in enriched solid pulp with the average glucan content of 75.9%. The majority of the hemicelluloses was hydrolysed into the aqueous-methanol phase, which contained 17.8 wt.% monomeric xylose and xylooligomers while 13.7 wt.% lignin was separated into the organic phase. The heterogeneous acid-promoter process is a potent alternative to corrosive homogeneous acids for lignocellulose fractionation in integrated biorefineries. PMID:24001557

  16. 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

  17. 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

  18. 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.

  19. Controlling hydrolysis and dispersion of AlN powders in aqueous media.

    PubMed

    Oliveira, M; Olhero, S; Rocha, J; Ferreira, J M F

    2003-05-15

    Aqueous suspensions of aluminum nitride (AlN) powders have been prepared in the presence of different surface-active agents, namely, H3PO4 and an anionic surfactant, to avoid the hydrolysis of AlN powders and to enhance dispersion. The most determinant parameters to the hydrolysis process (DeltapH and time of contact) and the stabilization of AlN particles in water (surface crystallinity, surface chemical modification, and surface ionic charge) were seen to be strongly dependent on the acidic agent. The H3PO4 treatment was effective against hydrolysis of AlN due to the formation of a phosphate-based protection layer on the particles' surface, and, although it keeps the pH of the suspension below 4, it does not guarantee a good dispersion. The individual adsorption of the anionic surfactant at the surface of AlN particles suspensions did not completely suppress the hydrolysis but it did enhance the degree of dispersion. A proper combination of the two types of surface-active agents enabled the preparation of AlN aqueous suspensions of relatively low viscosity and high AlN concentration, which can be a good starting point for aqueous-based colloidal shaping techniques or for freeze granulation or spray drying to obtain suitable granulate powder characteristics for dry-pressing technologies. An adsorption mechanism of the surface-active agents onto the particles' surface is proposed and supported by NMR and FT-IR analyses. PMID:16256556

  20. 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

  1. Solvent effect on proton transfer in the complexes of N,N-dimethylformamide with sulfuric and phosphoric acid: A DFT investigation

    NASA Astrophysics Data System (ADS)

    Fedorova, Irina V.; Krestyaninov, Michael A.; Kiselev, Michael G.; Safonova, Lyubov P.

    2016-02-01

    Ab initio quantum-chemical calculations of structure and energies of the complexes of N,N-dimethylformamide (DMF) with sulfuric (H2SO4) and phosphoric (H3PO4) acids have been carried out. It has been found that the hydrogen bond between H2SO4 and DMF molecules is a little shorter and stronger than that between H3PO4 and DMF. The H-bond strength is different both in acid-acid and (acid)n-DMF complexes for n = 1, 2. The polar solvent effect is taken into account by using the CPCM approach. The differences of geometric parameters of the H-bonds in the gas phase and DMF are analyzed. The potential energy surface (PES) of the proton transfer reaction in acid-DMF and (acid)2-DMF complexes was calculated. The calculations have shown that the gas phase PES has a single distinct minimum (with the exception of the (H2SO4)2-DMF). In DMF, the proton transfer reaction takes place in all complexes, if OACID … ODMF distance is constrained. The solvent effect favors a proton transfer from sulfuric acid to oxygen atom of DMF molecule and formation of stable ionic pairs.

  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. Electric double-layer capacitor using composites composed of phosphoric acid-doped silica gel and styrene-ethylene-butylene-styrene elastomer as a solid electrolyte

    NASA Astrophysics Data System (ADS)

    Matsuda, Atsunori; Honjo, Hiroshi; Hirata, Kazuki; Tatsumisago, Masahiro; Minami, Tsutomu

    Solid state electric double-layer capacitors have been fabricated using a composite composed of H 3PO 4-doped silica gel and styrene-ethylene-butylene-styrene elastomer as the electrolyte. A composite hybridized with activated carbon powders (ACP) was the polarizable electrode. The cyclic voltammogram of the electric double-layer capacitor fabricated demonstrated that electric charge was stored in the electric double-layer at the interface between the polarizable electrode and the electrolyte. Resistance of the capacitor obtained from impedance plots in ambient air was smaller by three orders of magnitude than that of the capacitor in a dry Ar atmosphere. The drastic decrease in the resistance should be ascribed to the increase in the proton conductivity of the composite due to the water adsorption in H 3PO 4-doped silica gel in an ambient atmosphere. The value of capacitance of the capacitor in an ambient atmosphere was 10 F/(gram of total ACP), which was 10 times larger than that of the capacitor in a dry Ar atmosphere. The large capacitance of the capacitor in an ambient atmosphere is attributable to the formation of electric double-layer with large electric charge at the interface between the composite and ACP in the capacitor due to the water adsorption.

  4. High-temperature supercapacitor with a proton-conducting metal pyrophosphate electrolyte

    NASA Astrophysics Data System (ADS)

    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.

  5. 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

  6. Chemometrics optimization of six antihistamines separations by capillary electrophoresis with electrochemiluminescence detection.

    PubMed

    Zhu, Derong; Li, Xia; Sun, Jinying; You, Tianyan

    2012-01-15

    This work expanded the knowledge of the use of chemometric experimental design in optimizing of six antihistamines separations by capillary electrophoresis with electrochemiluminescence detection. Specially, central composite design was employed for optimizing the three critical electrophoretic variables (Tris-H(3)PO(4) buffer concentration, buffer pH value and separation voltage) using the chromatography resolution statistic function (CRS function) as the response variable. The optimum conditions were established from empirical model: 24.2mM Tris-H(3)PO(4) buffer (pH 2.7) with separation voltage of 15.9 kV. Applying theses conditions, the six antihistamines (carbinoxamine, chlorpheniramine, cyproheptadine, doxylamine, diphenhydramine and ephedrine) could be simultaneous separated in less than 22 min. Our results indicate that the chemometrics optimization method can greatly simplify the optimization procedure for multi-component analysis. The proposed method was also validated for linearity, repeatability and sensitivity, and was successfully applied to determine these antihistamine drugs in urine. PMID:22265497

  7. 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.

  8. 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.

  9. High-temperature supercapacitor with a proton-conducting metal pyrophosphate electrolyte.

    PubMed

    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 Sn(0.95)Al(0.05)H(0.05)P(2)O(7) (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

  10. 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

  11. Antibacterial activity of calcium hydroxide combined with chitosan solutions and the outcomes on the bond strength of RealSeal sealer to radicular dentin

    PubMed Central

    Elsaka, Shaymaa Elsayed; Elnaghy, Amr Mohamed

    2012-01-01

    The purpose of this study was to investigate the antibacterial activity of calcium hydroxide [Ca(OH)2] combined with chitosan solutions against Enterococcus faecalis-infected root canal dentin and the effect of this new intracanal medicament on the bond strength of RealSeal sealer to radicular dentin. An experimental intracanal medicament was prepared by mixing different concentrations of chitosan solution (25%, 50%, and 100%, W/V) to Ca(OH)2 powder. Antibacterial activity was evaluated and the total numbers of colony forming units were determined. Bonding ability of RealSeal sealer to radicular dentin was evaluated using push-out bond strength test. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's multiple comparison tests. We found that Ca(OH)2 combined with different concentrations of chitosan solutions showed better antibacterial activity than Ca(OH)2 mixed with saline, without significantly affecting the bond strength of RealSeal sealer to radicular dentin (P > 0.05). The findings suggest that Ca(OH)2 combined with chitosan is a promising intracanal medicament and may be effective in endodontic therapy. PMID:23554749

  12. The effect of hydrogen peroxide solution on SO2 removal in the semidry flue gas desulfurization process.

    PubMed

    Zhou, Yuegui; Zhu, Xian; Peng, Jun; Liu, Yaobin; Zhang, Dingwang; Zhang, Mingchuan

    2009-10-15

    The present study attempts to use hydrogen peroxide solution to humidify Ca(OH)(2) particles to enhance the absorption of SO(2) to achieve higher removal efficiency and to solve the valuable reuse of the reaction product in the semidry flue gas desulfurization (FGD) process. Experiments were carried out to examine the effect of various operating parameters including hydrogen peroxide solution concentration, Ca/S molar ratio and approach to adiabatic saturation temperature on SO(2) removal efficiency in a laboratory scale spray reactor. The product samples were analyzed to obtain semi-quantitative measures of mineralogical composition by X-ray diffraction (XRD) with reference intensity ratio (RIR) method and the morphology of the samples was examined by scanning electron microscope (SEM). Compared with spraying water to humidify Ca(OH)(2), SO(2) removal efficiency was improved significantly by spraying hydrogen peroxide solution of 1-3 wt.% to humidify Ca(OH)(2) because hydrogen peroxide solution enhanced the dissolution and absorption rate of SO(2). Moreover, XRD and SEM analyses show that the desulfurization products contain less amount of unreacted Ca(OH)(2) and more amount of stable calcium sulfate with increasing hydrogen peroxide solution concentration. Thus, the process mechanism of the enhanced absorption of SO(2) by spraying hydrogen peroxide solution to humidify Ca(OH)(2) was elucidated on the basis of the experimental results. PMID:19464108

  13. The study of modified calcium hydroxides with surfactants for acid gas removal during incineration.

    PubMed

    Tseng, H H; Wey, M Y; Lu, C Y

    2002-01-01

    The primary objective of the present work is to use additives to extend the sulfation reaction of the calcium hydroxide (Ca(OH)2) used to control SO2 emission from incineration processes. There are two reasons for adding surfactants (surface-active agent): (1) to provide an appropriate dispersion of the Ca(OH)2', thus preventing particle agglomeration due to humidity; (2) to alter the sulfation reaction environment by adsorbing heterogeneous materials on the surface of the Ca(OH)2 to extend the adsorption equilibrium. A dry scrubber integrated with a fabric filter was employed to study the effect of surfactants on the removal efficiency of acid gas in the flue gas with Ca(OH)2 as the sorbent. The operating parameters evaluated include: (1) the different surfactants (calcium lignosulfonate, sodium lignosulfonate, alkyl naphthalene sodium sulfonate and beta-naphthalene sodium sulfonate condensates) and (2) the composition of acid gas (i.e. sulfur dioxide (SO2), nitrogen oxide (NO) and hydrogen chloride (HCl)). The results show that modified Ca(OH)2 with surfactants could effectively decrease the emission of acid gas during incineration. Different additives had individual absorption efficiencies on different acid gases. On the whole, sodium lignosulfonate and beta-naphthalene sodium sulfonate condensates had better sorption capacity for SO2 and NO, but not for HCl. In addition, when SO2 coexisted with NO and HCl, the concentration of NO and HCl will result in decrease or increase of the removal efficiency of SO2. PMID:11924579

  14. 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

  15. 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

  16. 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

  17. [Effect of calcium hydroxide concentration and cooking time of corn grain (Zea mays L.) nixtamalized, over physicochemical and rheological nixtamal characteristics].

    PubMed

    Castillo, V K C; Ochoa, M l A; Figueroa, C J D; Delgado, L E; Gallegos, I J A; Morales, C J

    2009-12-01

    The effect of calcium hydroxide (Ca(OH)2) concentration and cooking time on physicochemical and pasting properties of maize, during traditional nixtamalization was evaluated. It was observed that the higher the Ca(OH)2 concentration and cooking time the higher the gelatinization temperature. Grain samples treated with 2 g/100 g of Ca(OH)2 and 60 min of cooking time presented higher calcium absorption (0.152 g/100 g) showing a significant increment (approximately 500 g/100 g). Results of X-ray diffraction showed that all the samples had X-ray diffraction pattern of starch type A, showing differences in the intensity of the diffraction as indicated by the percentage of cristallinity. The apparent viscosity of the nixtamal considerably decreased when the processes conditions were higher. Water retention capacity increased with temperature. PMID:20677458

  18. Optimization of the Alkaline Pretreatment of Rice Straw for Enhanced Methane Yield

    PubMed Central

    Song, Zilin; Yang, Gaihe; Han, Xinhui; Feng, Yongzhong; Ren, Guangxin

    2013-01-01

    The lime pretreatment process for rice straw was optimized to enhance the biodegradation performance and increase biogas yield. The optimization was implemented using response surface methodology (RSM) and Box-Behnken experimental design. The effects of biodegradation, as well as the interactive effects of Ca(OH)2 concentration, pretreatment time, and inoculum amount on biogas improvement, were investigated. Rice straw compounds, such as lignin, cellulose, and hemicellulose, were significantly degraded with increasing Ca(OH)2 concentration. The optimal conditions for the use of pretreated rice straw in anaerobic digestion were 9.81% Ca(OH)2 (w/w TS), 5.89 d treatment time, and 45.12% inoculum content, which resulted in a methane yield of 225.3 mL/g VS. A determination coefficient (R2) of 96% was obtained, indicating that the model used to predict the anabolic digestion process shows a favorable fit with the experimental parameters. PMID:23509824

  19. Removing Al and regenerating caustic soda from the spent washing liquor of Al etching

    NASA Astrophysics Data System (ADS)

    Barakat, M. A.; El-Sheikh, S. M.; Farghly, F. E.

    2005-08-01

    Spent liquor from washing of aluminum section materials after etching with caustic soda (NaOH) has been treated. Aluminum was removed from the liquor and caustic soda was regenerated by adding precipitating agents to hydrolyze sodium aluminate (Na2AlO2), separating the aluminumprecipitate, and concentrating free NaOH in the resulting solution for reuse in the etching process. Four systems were investigated: hydrated lime [Ca(OH)2], hydrogen peroxide (H2O2), H2O2/Ca(OH)2 mixture, and dry lime (CaO). Results revealed that CaO was more efficient in the removal of aluminum from the spent liquor with a higher hydrolyzing rate of Na2AlO2 than Ca(OH)2, H2O2, or their mixture.

  20. 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 ...

  1. 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

  2. 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.

  3. Thiol-dependent passive K/Cl transport in sheep red cells: VII. Volume-independent freezing by iodoacetamide, and sulfhydryl group heterogeneity.

    PubMed

    Lauf, P K

    1987-01-01

    The sulfhydryl (SH) reagent iodoacetamide (IAAM) inhibits stimulation of Cl-dependent K transport in low K (LK) sheep red cells by another SH reagent, N-ethylmaleimide (NEM), without itself activating this transport pathway (J. Membrane Biol., 1983, 73:257-261). We now report that IAAM alone, acting with a kinetic slower than NEM, sharply reduced the capability of the Cl-dependent K transport system to regulate its activity in response to cell volume changes. This effect of IAAM did not depend on the cell volume maintained during chemical treatment, a fact ruling out that the reactivity of the SH groups with IAAM was a function of the volume-dependent turnover rate of the transporter. On the other hand, the prevention of the NEM-stimulatory effect on Cl-dependent K transport was found to be volume-dependent since 1) the rate with which IAAM blocked the subsequent NEM action was twice as fast in cells swollen in 250 mOSM as opposed to cells shrunken in 370 mOSM media, and 2) the dose response of the IAAM effect was different in swollen and shrunken cells. The action of IAAM with or without subsequent treatment with NEM seemed to be independent of cellular ATP which is required for full expression of the stimulatory modification of Cl-dependent K transport by NEM (Am. J. Physiol., 1983, 245:C445-C448). Clusters of SH groups on the Cl-dependent K transporter apparently react differently with IAAM and NEM when separately applied but, used in combination, reflect a complex volume-dependent effect that may reveal a "volume-sensing" component of the transport molecule. PMID:3681954

  4. 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

  5. Removal efficiency of calcium hydroxide dressing from the root canal.

    PubMed

    Lambrianidis, T; Margelos, J; Beltes, P

    1999-02-01

    The aim of this study was to investigate whether differences in the composition of calcium hydroxide (Ca(OH)2) preparations influence the removal efficiency of irrigation solutions used in combination with filing of the canal. Three Ca(OH)2 preparations were used: Calxyl, Pulpdent paste, and chemically pure Ca(OH)2 mixed with distilled water. Fifty-one single-rooted extracted human teeth were prepared with a step-back technique and divided into groups A, B, and C. In each group, 15 teeth were assigned to each Ca(OH)2 preparation while the remaining two served as positive and negative controls. Each group of treated teeth was divided into three subgroups of five teeth each: subgroup I--canals were irrigated with saline, filed with a #25 file, and finally flushed with saline; subgroup II--canals were irrigated with NaOCl, filed with a #25 file, and finally flushed with NaOCl; and subgroup III--canals were irrigated with NaOCl, filed with a #25 file, and finally flushed with tetrasodium EDTA. Canal sections were then photographed, and the percentage ratios of Ca(OH)2 coated area to the total canal surface area were calculated by image processing analysis. Results revealed: (a) none of the methods efficiently removed all dressing from the walls, and (b) concentration of the paste used had little effect on the efficacy of the methods applied for the removal of the dressing. Excipients (i.e. methylcellulose contained in Pulpdent) possibly effect retention of Ca(OH)2. PMID:10204462

  6. 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

  7. Thermochemical energy storage for a lunar base

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Mckissock, Barbara I.; Difilippo, Frank

    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.

  8. 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.

  9. 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 μg 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 (δ18O and δD) 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.

  10. 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.

  11. Preparation and properties of titanium oxide film on NiTi alloy by micro-arc oxidation

    NASA Astrophysics Data System (ADS)

    Wang, H. R.; Liu, F.; Zhang, Y. P.; Yu, D. Z.; Wang, F. P.

    2011-04-01

    Titanium oxide ceramic coatings were prepared by micro-arc oxidation (MAO) in galvanostatic regime on biomedical NiTi alloy in H3PO4 electrolyte using DC power supply. The surface of the coating exhibited a typical MAO porous and rough structure. The XPS analysis indicated that the coatings were mainly consisted of O, Ti, P, and a little amount of Ni, and the concentration of Ni was greatly reduced compared to that of the NiTi substrate. The TF-XRD analysis revealed that MAO coating was composed of amorphous titanium oxide. The coatings were tightly adhesive to the substrates with the bonding strength more than 45 MPa, which was suitable for medical applications. The curves of potentiodynamic porlarization indicated that the corrosion resistance of NiTi alloy was significantly improved due to titanium oxide formation on NiTi alloy by MAO.

  12. Quantifying phosphoric acid in high-temperature polymer electrolyte fuel cell components by X-ray tomographic microscopy.

    PubMed

    Eberhardt, S H; Marone, F; Stampanoni, M; Büchi, F N; Schmidt, T J

    2014-11-01

    Synchrotron-based X-ray tomographic microscopy is investigated for imaging the local distribution and concentration of phosphoric acid in high-temperature polymer electrolyte fuel cells. Phosphoric acid fills the pores of the macro- and microporous fuel cell components. Its concentration in the fuel cell varies over a wide range (40-100 wt% H3PO4). This renders the quantification and concentration determination challenging. The problem is solved by using propagation-based phase contrast imaging and a referencing method. Fuel cell components with known acid concentrations were used to correlate greyscale values and acid concentrations. Thus calibration curves were established for the gas diffusion layer, catalyst layer and membrane in a non-operating fuel cell. The non-destructive imaging methodology was verified by comparing image-based values for acid content and concentration in the gas diffusion layer with those from chemical analysis. PMID:25343801

  13. Structural engineering for high energy and voltage output supercapacitors.

    PubMed

    Xu, Jing; Wu, Hui; Xu, Chen; Huang, Hongtao; Lu, Linfeng; Ding, Guqiao; Wang, Huili; Liu, Dongfang; Shen, Guozhen; Li, Dongdong; Chen, Xiaoyuan

    2013-05-10

    High capacitance and high output voltage are two important research focuses of electrochemical supercapacitors. Herein we present two novel designs (laminated and tandem) of coin-cell supercapacitors based on a textile coated with active material. The fabric electrodes were prepared by dipping the non-woven cloth into a dispersion of carbon nanotubes and subsequent MnO2 electrodeposition. In the lamination configuration, several pieces of active-material-coated cloth were laminated to construct individual electrodes that enable fold-increased areal capacitances and excellent cycling stability. In the tandem structure, individual cells with solid-state electrolyte (polyvinyl alcohol/H3PO4) sandwiched between the fabric electrodes were stacked together to form a single device. The assembled device composed by ten unit cells was demonstrated to drive four LED digital screens in series with 10 V output. PMID:23520077

  14. 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.

  15. 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.

  16. Solubilitéet croissance de la berlinite AlPO 4, en milieu phospho-sulfurique

    NASA Astrophysics Data System (ADS)

    Cambon, O.; Goiffon, A.; Philippot, E.

    1989-01-01

    La solubilitéde la berlinite, AlPO 4, aétémesurée dans des mélanges d'acide phosphorique et sulfurique en différentes proportions. Dans ces milieux, la solubilitéest toujours de type rétrograde et intermédiaire entre celle déterminée dans chacun des deux acides. La croissance cristalline réalisée dans ce solvant mixte conduita`des cristaux dont la morphologie est elle aussi intermédiairea`celles observées dans H 3PO 4 et H 2SO 4. Cette observation montre que l'utilisation de mélanges d'acide permet de moduler les vitesses de croissance et peuteˆtre un moyen de mieux maiˆtriser celles-ci.

  17. 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.

  18. Poly(vinylimidazole) radiografted PVDF nanospheres as alternative binder for high temperature PEMFC electrodes

    NASA Astrophysics Data System (ADS)

    Galbiati, Samuele; Coulon, Pierre-Eugène; Rizza, Giancarlo; Clochard, Marie-Claude; Castellino, Micaela; Sangermano, Marco; Nayoze, Christine; Morin, Arnaud

    2015-11-01

    Within the framework of high-temperature polymer fuel cells doped with phosphoric acid, we investigate the replacement of the conventional binder in the catalyst layers by functionalized solid PVDF nanospheres. Aim of this study is to develop and test an innovative binder which might create enhanced electrode porosity and acid distribution. Aqueous suspensions of PVDF nanospheres (d ∼ 200 nm) are obtained by radical emulsion polymerization and are functionalized by Vinyl-Imidazole (VI) groups via in situ γ-radiation. As a consequence the nanospheres can interact with H3PO4 to obtain proton conductivity. Catalyst inks are prepared mixing the nanospheres with commercial Pt/C electrocatalyst powder, solvents and phosphoric acid. Prototype electrodes are deposited by spraying and preliminary fuel cell tests are carried out at 160 °C under dry H2/air. Electrodes with grafted PVDF nanospheres as solid binder are demonstrated and its understanding is in progress. Further improvements are outlined.

  19. Blue emission of YMO 4:Eu 2+ (M=V,P) nanocrystals prepared through facile wet process

    NASA Astrophysics Data System (ADS)

    Iwasaki, Mitsunobu; Yamashita, Naoki; Taguchi, Masato; Karuppucharmy, Subbian; Ito, Seishiro; Park, Wonkyu

    2006-08-01

    Nanometer-sized YPO 4:Eu and YVO 4:Eu particles were prepared from alkaline alcohol-water mixture with Y(NO 3) 3 6H IIO, EuCl 3 and H 3PO 4 (or NH 4VO 4) under reflux. The resultant particles were well crystallized ranging 10-50 nm in diameter by changing reaction conditions. Europium ions in YPO 4:Eu and YVO 4:Eu was successfully reduced to Eu 2+ ions by sodium borohydride under reflux. The peak position of blue emission due to Eu 2+ ions (4f-5d transition) in nanocrystals was different among the materials (Y IIO 3, YVO 4 and YPO 4).

  20. 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.

  1. Characterization of Spin-on Dopant by Sol-gel Method

    NASA Astrophysics Data System (ADS)

    Kamil, S. Ahmad; Ibrahim, K.; Aziz, A. Abdul

    2008-05-01

    P-N junction is a basic building block for many important electron devices from as simple as a solar cell to very complicated integrated circuit. In this work, spin-on dopant (SOD) was used as the diffusion source in order to create p-n junction. SOD was prepared by using sol gel method. The spin-on dopant solution ingredients contain tetraethylorthosilicate (TEOS), isopropanol (IPA), distilled water (H2O), acetone and phosphoric acid (H3PO4). The coated silicon wafers were put inside the conventional furnace for predepostion and drive in oxidation. Effect caused by varying the molarity of the acid were observed and studied using Hall Effect measurement by comparing their differences in sheet resistance, mobility, resistivity as well as sheet and bulk concentaration.

  2. Adsorption studies of chromium (VI) on activated carbon derived from Sorghum vulgare (dried stem of Jowar).

    PubMed

    Mise, Shashikant R; Rajamanya, V S

    2003-01-01

    The present work deals with the adsorption studies of chromium (VI) on activated carbon derived from Sorghum vulgare (dried stem of Jowar). The activated carbons were prepared by physical and chemical activation using H2SO4, H3PO4 activating agents of different imprignation Ratio (I.R.). The effect of adsorption of Cr (VI) on pH, particle size concentration, contact time and dosage have been studied. Removal of chromium (VI) attained in equilibrium maxium of 50 minutes and slightly decreases with increasing I.R. Adsorption obeys first order rate equation and Webber and Morris equation for pore diffusion. Adsorption increases with decrease in pH, is maximum at pH 2. Increase in imprignation ratio also increases surface area of Sorghum vulgare carbons. PMID:14723283

  3. Epitaxial quality of thin Ag films on GaAs(100) surfaces cleaned with various wet etching techniques

    NASA Astrophysics Data System (ADS)

    Mello, K. E.; Soss, S. R.; Murarka, S. P.; Lu, T.-M.; Lee, S. L.

    1996-01-01

    2θ and pole figure x-ray analysis have been used to examine the crystal structure and orientation of Ag films deposited on GaAs(100) substrates cleaned by a variety of wet etches. Where epitaxy was observed, it was of the type Ag(110)/GaAs(100). The H3PO4/HCl sequential etch yielded the film with the highest degree of preferred orientation, with the H2SO4/HCl, NH4OH, and HF etches producing films of decreasing quality in the order named. The epitaxial quality is thought to scale with elemental As concentration on the GaAs(100) surface, and have an inverse relationship to the amount of surface oxides present before deposition.

  4. On-substrate fabrication of porous Al2O3 templates with tunable pore diameters and interpore distances

    NASA Astrophysics Data System (ADS)

    Berger, Nele; Habouti, Salah; Rubahn, Horst-Günter; Es-Souni, Mohammed

    2016-03-01

    This work is focused on the on-substrate fabrication of porous aluminum oxide templates by anodization of a thin aluminum film deposited directly on the substrate using different concentrations of oxalic acid. These on-substrate templates are used for fabricating supported, free-standing nanorod (NR)-arrays by electrochemical deposition of Pt followed by the removal of the template. The interpore distance of the templates is tuned by varying the concentration of the electrolyte used for anodization and the applied voltage. The diameter of the pores (and thus the NRs of the resulting array) and wall thickness are influenced by modifying the pore opening time during immersion the sample in H3PO4.

  5. Cleaner production in the ammonia-soda industry: an ecological and economic study.

    PubMed

    Kasikowski, T; Buczkowski, R; Lemanowska, E

    2004-12-01

    Five methods to reduce the negative influence of soda ash factories on the natural environment are presented: 1. obtaining calcium-magnesium phosphates by treating the suspension from raw brine purification with orthophosphoric acid (H(3)PO(4)), 2. production of precipitated chalk from soda processing waste, 3. production of gypsum and semi-brine, 4. desulphurisation of fume gases from the factory power plant, 5. utilization of distiller waste. The tests, accomplished on a laboratory scale, showed the high efficiency of these methods. Economic analysis has proved that only four out of the five presented processes can have a positive financial effect on soda ash factories, as well as being well justified economically. The value of two of the innovations presented is confirmed by their implementation in factories. PMID:15531392

  6. Validation of an HPLC method for the quantification of ambroxol hydrochloride and benzoic acid in a syrup as pharmaceutical form stress test for stability evaluation.

    PubMed

    Heinänen, M; Barbas, C

    2001-03-01

    A method is described for ambroxol, trans-4-(2-amino-3,5-dibromobenzylamino) cyclohexanol hydrochloride, and benzoic acid separation by HPLC with UV detection at 247 nm in a syrup as pharmaceutical presentation. Optimal conditions were: Column Symmetry Shield RPC8, 5 microm 250 x 4.6 mm, and methanol/(H(3)PO(4) 8.5 mM/triethylamine pH=2.8) 40:60 v/v. Validation was performed using standards and the pharmaceutical preparation which contains the compounds described above. Results from both standards and samples show suitable validation parameters. The pharmaceutical grade substances were tested by factors that could influence the chemical stability. These reaction mixtures were analysed to evaluate the capability of the method to separate degradation products. Degradation products did not interfere with the determination of the substances tested by the assay. PMID:11248495

  7. 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

  8. Effects of acid and alkali promoters on compressed liquid hot water pretreatment of rice straw.

    PubMed

    Imman, Saksit; Arnthong, Jantima; Burapatana, Vorakan; Champreda, Verawat; Laosiripojana, Navadol

    2014-11-01

    In this study, effects of homogeneous acid and alkali promoters on efficiency and selectivity of LHW pretreatment of rice straw were studied. The presences of acid (0.25%v/v H2SO4, HCl, H3PO4, and oxalic acid) and alkali (0.25 w/v NaOH) efficiently promoted hydrolysis of hemicellulose, improved enzymatic digestibility of the solids, and lower the required LHW temperature. Oxalic acid was a superior promoter under the optimal LHW conditions at 160 °C, leading to the highest glucose yield from enzymatic hydrolysis (84.2%) and the lowest formation of furans. Combined with hydrolyzed glucose in the liquid, this resulted in the maximal 91.6% glucose recovery from the native rice straw. This was related to changes in surface area and crystallinity of pretreated biomass. The results showed efficiency of external promoters on increasing sugar recovery and saving energy in LHW pretreatment. PMID:25181697

  9. 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.

  10. Novel Application of ZSM-5 Zeolite: Corrosion-Resistant Coating in Chemical Process Industry

    NASA Astrophysics Data System (ADS)

    Pande, H. B.; Parikh, P. A.

    2013-01-01

    As-synthesized zeolite ZSM-5 containing the structure-directing agent, tetrapropyl ammonium bromide, when used as a coating material on mild steel substrate material, has been found to offer a promising corrosion resisting results against HCl, HNO3, H3PO4, and H2SO4 of various concentrations at temperatures up to 60 C under stagnant and stirred conditions. Stable and continuous coated layer is observed under the conditions studied in this work by weight loss and electrochemical methods. Encouraging results in terms of corrosion inhibition efficiency indicate high potential with zeolite (Si/Al ratio 25) material. Material costs compare favorably for zeolite coating against the conventionally used materials. Summarily, zeolite offers an environment-friendly and cost-effective alternate to the other toxic and carcinogenic materials as corrosion-resistant coating.

  11. [Chiral separation of dipeptides by capillary electrophoresis].

    PubMed

    Cheng, Yan; Bai, Min; Wang, Xinmei; Ming, Yongfei; You, Jinmao

    2006-03-01

    Peptides are increasingly used as pharmaceutical agents. Many small peptides are the essential compounds in biological systems. Direct chiral separation of dipeptide derivatives using 9-(2-carbazole) ethyl chloroformate (CEOC) as the derivatizing agent by capillary electrophoresis (CE) with beta-cyclodextrin (beta-CD) and sodium deoxycholate (SDC) as chiral selectors has been developed. It has been well recognized that the combination of the binary selectors can enhance the selectivity and resolution instead of either beta-CD or SDC alone. The molar ratio of the binary chiral selectors, the buffer concentration and pH of Tris-H3PO4, organic modifier were studied and optimized. Complete chiral separations for 14 dipeptide derivatives using beta-CD and SDC as binary chiral selectors were obtained. The results indicated that each pair of D/L chiral resolution was more than 3.63, and the highest resolution for Gly-Ala was 43.14. PMID:16830473

  12. Optical Properties of Rhodamine 6G Doped A1PO4 Gel

    NASA Astrophysics Data System (ADS)

    Li, Ri-Hong; Tang, Bin; Fan, You-Yu; Ren, Jin-Jun; Zhang, Long

    2010-10-01

    Homogeneous monolith of A1PO4 gel doped with rhodamine 6G (Rh6G) at different dye loadings is prepared by a one-step process with sol-gel method using the precursors A1(lact)3 and H3PO4. The optical properties of A1PO4 gel doped with Rh6G are characterized by UV-Visible absorption spectra and fluorescence spectra. Rh6G molecular J-dimers and H-dimers even multimers are analyzed by excitation spectra based on exciton theory. The A1PO4 gel doped with Rh6G dye with molar ratio of Rh6G/A1(lact)3 of 1 × 10-4 has excellent optical properties without obvious aggregates.

  13. Fabrication of GaAs symmetric pyramidal mesas prepared by wet-chemical etching using AlAs interlayer

    NASA Astrophysics Data System (ADS)

    Kicin, S.; Cambel, V.; Kuliffayová, M.; Gregušová, D.; Kováčová, E.; Novák, J.; Kostič, I.; Förster, A.

    2002-01-01

    We present a wet-chemical-etching method developed for the preparation of GaAs four-sided pyramid-shaped mesas. The method uses a fast lateral etching of AlAs interlayer that influences the cross-sectional profiles of etched structures. We have tested the method using H3PO4:H2O2:H2O etchant for the (100) GaAs patterning. The sidewalls of the prepared pyramidal structures together with the (100) bottom facet formed the cross-sectional angles 25° and 42° for mask edges parallel, resp. perpendicular to {011} cleavage planes. For mask edges turned in 45° according to the cleavage planes, 42° cross-sectional angles were obtained. Using the method, symmetric and more than 10-μm-high GaAs "Egyptian" pyramids with smooth tilted facets were prepared.

  14. 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.

  15. 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

  16. Surface morphology of highly ordered nanotube formed and laser textured beta titanium alloys.

    PubMed

    Kim, Jae-Un; Jeong, Yong-Hoon; Choe, Han-Cheol

    2013-03-01

    The aim of the present study is to produce and characterize a well-controlled surface texture on Ti-35Nb-xHf alloys to promote osseointegration. Ti-35Nb-xHf (x = 0, 3, 7 and 15 wt.%) alloys were prepared by arc melting and heat treated for 12 hr at 1000 degrees C in an argon atmosphere and then water quenching. For surface texturing, an amplified Ti: sapphire laser system was used for generating 184 femtosecond (FS, 10(-15) sec) laser pulses with the pulse energy over 30 mJ at a 1 kHz repetition rate with a central wavelength of 800 nm. The nanotube formation was achieved by anodizing a Ti-35Nb-xHf alloy in H3PO4 electrolytes containing 0.8 wt.% NaF at room temperature. The surface morphology of nano/micro structure will enhance osseointegration and cell adhesion. PMID:23755610

  17. Direct fabrication of TiO2 nanoparticles deposited on hydroxyapatite crystals under mild hydrothermal conditions.

    PubMed

    Sujaridworakun, Pornapa; Pongkao, Dujreutai; Ahniyaz, Anwar; Yamakawa, Yasuaki; Watanabe, Tomoaki; Yoshimura, Masahiro

    2005-06-01

    TiO2 nanoparticles-deposited on hydroxyapatite (HAp) have been successfully synthesized by direct (single step) hydrothermal treatments of a CaCO3 suspension in a H3PO4 solution with 10 vol% TAS-FINE (titanium amine complex) at 150 degrees C for 6 h or 120 degrees C for 12-24 h under nearly neutral pH conditions. The obtained products were characterized by XRD, SEM-EDX, visible, Raman, and TEM. The XRD and Raman results showed the formation of HAp and TiO2 anatase phases under these hydrothermal conditions. SEM and TEM observations revealed that anatase TiO2 nanoparticles with the size of about 10 nm were deposited on the surfaces of the HAp crystals. PMID:16060146

  18. 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.

  19. Biocompatibility of nanotube formed Ti-30Nb-7Ta alloys.

    PubMed

    Kim, Eun-Sil; Choe, Han-Cheol

    2014-11-01

    The purpose of this study was to investigate the biocompatibility of Ti-30Nb-7Ta alloy surface decorated with TiO2 nanotubes by anodization in an electrolyte containing 1 M H3PO4 and 0.8 wt.% NaF with an applied voltage of 10 V for 2 h. The anodization was carried out using a scanning potentiostat. The microstructures of alloys and morphology of the nanotubes were investigated by optical microscopy, field emission scanning electron microscopy, and X-ray diffractometry. In comparison to the Ti-30Nb-3Ta alloy, the Ti-30Nb-7Ta alloy contained a lower amount of α" phase, while the β phase was higher. In this study, we observed the formation of a spongy porous layer on the Ti-30Nb-7Ta alloy, while the Ti-30Nb and Ti-30Nb-3Ta alloys showed an absence of such a spongy layer. PMID:25958540

  20. 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.

  1. 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

  2. [Catalytic properties of alpha-ketoglutarate decarboxylase from bovine brain].

    PubMed

    Snechkute, M A; Glemzha, A A

    1976-03-01

    Investigation of the effect of different buffer systems on the rate of alpha-ketoglutarate decarboxylase reaction have shown that the pH optimum is 6.8 in tris-maleic, tris-H3PO4 and KH2PO4-KOH buffers, and it is 7.5 in imidazole buffer. The highest reaction rate was observed when using phosphate containing buffers. The increase of phosphate concentration increased considerably the rate of alpha-ketoglutarate decarboxylase reaction. Mg2+ and Ca2+ were shown to affect slightly the reaction rate. Co2+ and Ag+ slightly inactivated the enzyme. Cu2+ turned to be a very efficient inhibitor of alpha-ketoglutarate decarboxylase reaction. Apparent Mikhaelis constants are determined to be 1.6-10(-3) M for alpha-ketoglutaric acid and 1.7-10(-2)M for 2,6-dichlorphenolindophenol. PMID:6080

  3. Valorization of phosphogypsum as hydraulic binder.

    PubMed

    Kuryatnyk, T; Angulski da Luz, C; Ambroise, J; Pera, J

    2008-12-30

    Phosphogypsum (calcium sulfate) is a naturally occurring part of the process of creating phosphoric acid (H(3)PO(4)), an essential component of many modern fertilizers. For every tonne of phosphoric acid made, from the reaction of phosphate rock with acid, commonly sulfuric acid, about 3t of phosphogypsum are created. There are three options for managing phosphogypsum: (i) disposal or dumping, (ii) stacking, (iii) use-in, for example, agriculture, construction, or landfill. This paper presents the valorization of two Tunisian phosphogypsums (referred as G and S) in calcium sulfoaluminate cement in the following proportions: 70% phosphogypsum-30% calcium sulfoaluminate clinker. The use of sample G leads to the production of a hydraulic binder which means that it is not destroyed when immersed in water. The binder including sample S performs very well when cured in air but is not resistant in water. Formation of massive ettringite in a rigid body leads to cracking and strength loss. PMID:18433998

  4. [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

  5. 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 μg/L, 13.10-24.32 μg/L, 1.87-6.42 μg/g, and 3.37-9.06 μg/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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. Liquid chromatographic preparative method for isolating ergot alkaloids, using a particle-loaded membrane extracting disk.

    PubMed

    Ware, G M; Price, G; Carter, L; Eitenmiller, R R

    2000-01-01

    A liquid chromatographic method is described for the determination of ergot alkaloids in wheat. Ergonovine, ergotamine, ergocornine, alpha-ergocryptine, and ergocristine are extracted from wheat with methanol-0.25% concentrated H3PO4 (40 + 60) pH 2.2, cleaned up by using a solid-phase extraction (SPE) disk, and separated by reversed-phase liquid chromatography with fluorescence detection. Ergot alkaloids are basic compounds that form water-soluble salts in acidic aqueous solution. Because ergot alkaloid salts are positively charged, they can be easily and selectively trapped on a negatively charged strong cation-exchange SPE disk. A strong wash solvent, methanol-0.25% concentrated H3PO4 (40 + 60) was used to remove matrix interferences not bonded by ionic interactions with the cation-exchange column. The ergot alkaloids were eluted from the ion-exchange column by adjusting the pH of the elution solvents to slightly basic conditions (pH 9). The SPE disk concentrated and cleanly separated the ergot alkaloids from matrix interferences. Standard calibration curves for ergot alkaloids for the concentration range 0.1-2.0 microg/mL were linear. The SPE disk had a column capacity equivalent to about 1 g extracted wheat. At spiking levels of 2.3-46 ng/g for ergonovine and 20-400 ng/g for ergotamine, ergocornine, alpha-ergocryptine, and ergocristine, the mean recovery was 88.1% with a coefficient of variation (CV) of 5.33%. The recovery data ranged from 79.1 to 95.9%. Ergonovine had the lowest overall recovery and the largest CV. The method has an estimated reliable limit of detection and limit of quantitation of <5 and <20 ng/g, respectively, for each ergot alkaloid tested. PMID:11128143

  11. Scalable synthesis of hierarchically structured carbon nanotube-graphene fibres for capacitive energy storage.

    PubMed

    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 m(2) 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)/H(3)PO(4) electrolyte (measured at 26.7 mA cm(-3) in a two-electrode cell). A full micro-supercapacitor with PVA/H(3)PO(4) 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. PMID:24813695

  12. 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.

  13. Modification Strategies with Inorganic Acids for Efficient Photocatalysts by Promoting the Adsorption of O2.

    PubMed

    Li, Zhijun; Luan, Yunbo; Qu, Yang; Jing, Liqiang

    2015-10-21

    Efficient photocatalysis for degrading environmental organic pollutants on semiconductors requires photogenerated charge carrier separation to drive the photochemical processes. To ensure charge separation, it is indispensable to make charges captured effectively. Generally, the step for capturing the photogenerated electrons by the surface adsorbed O2 is relatively slow as compared to that for capturing holes by the surface adsorbed hydroxyl groups so that it is taken as the rate-determining step. However, it is frequently neglected. Thus, it is greatly desired to develop feasible strategies to promote the adsorption of O2 for efficient photocatalysts. In this paper, we have mainly discussed surface modification with inorganic acids, such as H3PO4, HF, and H3BO3, to enhance photogenerated charge carrier separation based on oxygen adsorption promotion for photocatalytic degradation of environmental pollutants. Among these acids, the function and mechanism of H3PO4 are highlighted because of its good performance and universality. Several important photocatalyst systems, mainly including TiO2, α-Fe2O3, and g-C3N4, along with the nanostructured carbons as electron acceptors in nanocomposites, are addressed to improve the ability to adsorb O2. A key consideration in this review is the development of a strategy for the promotion of adsorbed O2 for efficient photocatalysts, along with the process mechanisms by revealing the relationships among the adsorbed O2, photogenerated charge carrier separation, and photocatalytic performance. Interestingly, it is suggested that the enrichment in surface acidity be favorable for promotion of O2 adsorption, leading to the improved charge carrier separation and then to the enhanced photoactivities of various semiconductor photocatalysts. Moreover, several outlooks are put forward. PMID:26426144

  14. Enamel morphology after microabrasion with experimental compounds

    PubMed Central

    Pini, Núbia I.P.; Costa, Rafaela; Bertoldo, Carlos E.S.; Aguiar, Flavio H. B.; Lovadino, José R.; Lima, Débora Alves Nunes Leite

    2015-01-01

    Background: Enamel microabrasion is an esthetic treatment for removing superficial stains or defects of enamel. Aim: This study evaluated the roughness after enamel microabrasion using experimental microabrasive systems. Materials and Methods: One hundred and ten samples (5 × 5 mm) were obtained from bovine incisors and divided into 11 groups (n = 10) in accordance with the treatment: Microabrasion using 6.6% hydrochloric acid (HCl) or 35% phosphoric acid (H3PO4) associated with aluminum oxide (AlO3) or pumice (Pum) with active application (using rubber cup coupled with a micro-motor of low rotation) or passive application (just placing the mixture on the enamel surface); just the use of acids in a passive application (negative control), and a group without treatment (positive control). Roughness analysis was performed before and after treatments. The statistical analysis used analysis of variance (PROC MIXED), Tukey-Kramer and Dunnet tests (P < 0.05). Representative specimens were evaluated using scanning electron microscopy (SEM). Results: There was no significant difference between the acids used (P = 0.0510) and the applications (P = 0.8989). All of the treated groups were statistically different from the positive control. When using passive application, the use of HCl + AlO3 resulted in higher roughness when compared with HCl + Pum. Additionally, this treatment was statistically different from the passive application of H3PO4 (negative control) (P < 0.05). However, SEM analysis showed that the treatment with AlO3 resulted in an enamel surface with a more polished aspect when compared with Pum. Conclusion: AlO3 may be a suitable particle for use in microabrasive systems. PMID:26097350

  15. Combined electron capture and infrared multiphoton dissociation for multistage MS/MS in a Fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Håkansson, Kristina; Chalmers, Michael J; Quinn, John P; McFarland, Melinda A; Hendrickson, Christopher L; Marshall, Alan G

    2003-07-01

    We have mounted a permanent on-axis dispenser cathode electron source inside the magnet bore of a 9.4-T Fourier transform ion cyclotron resonance mass spectrometer. This configuration allows electron capture dissociation (ECD) to be performed reliably on a millisecond time scale. We have also implemented an off-axis laser geometry that enables simultaneous access to ECD and infrared multiphoton dissociation (IRMPD). Optimum performance of both fragmentation techniques is maintained. The analytical utility of performing either ECD or IRMPD on a given precursor ion population is demonstrated by structural characterization of several posttranslationally modified peptides: IRMPD of phosphorylated peptides results in few backbone (b- and y-type) cleavages, and product ion spectra are dominated by neutral loss of H3PO4. In contrast, ECD provides significantly more backbone (c- and z*-type) cleavages without loss of H3PO4. For N-glycosylated tryptic peptides, IRMPD causes extensive cleavage of the glycosidic bonds, providing structural information about the glycans. ECD cleaves all backbone bonds (except the N-terminal side of proline) in a 3-kDa glycopeptide with no saccharide loss. However, only a charge-reduced radical species and some side chain losses are observed following ECD of a 5-kDa glycopeptide from the same protein. An MS3 experiment involving IR laser irradiation of the charge-reduced species formed by electron capture results in extensive dissociation into c- and z-type fragment ions. Mass-selective external ion accumulation is essential for the structural characterization of these low-abundance (modified) peptides. PMID:12964777

  16. Organometallic catalysts for primary phosphoric acid fuel cells

    NASA Astrophysics Data System (ADS)

    Walsh, Fraser

    1987-03-01

    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.

  17. Mechanism of Efficient Proton Conduction in Diphosphoric Acid Elucidated via First-Principles Simulation and NMR.

    PubMed

    Krueger, Rachel A; Vilčiauskas, 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 (σ ≈ 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

  18. Influence d'une substitution partielle du ciment par du laitier de hauts fourneaux sur la résistance des mortiers en milieu acide

    NASA Astrophysics Data System (ADS)

    Achoura, D.; Lanos, Ch.; Jauberthie, R.; Redjel, B.

    2004-11-01

    Le stockage de produits chimiques dans du béton présente souvent des problèmes de durabilité dus aux attaques chimiques. Inévitablement les concentrations élevées sont les plus dangereuses. Le but de notre étude est de déterminer les changements de phases qui apparaissent dans le béton lorsqu'on substitue une partie du ciment par du laitier de haut fourneaux. Les échantillons sont conservés dans des solutions acides différents anions (HCl, H{2}SO{4}, H{3}PO{4} et CH{3}COOH) et différentes concentrations (0,1; 0,25 et 0,5M). Les formations qui apparaissent sont déterminées par diffraction X et observées au MEB. Les solutions sulfatiques conduisent à une formation de gypse en surface et d'ettringite au contact de la matrice cimentaire. Avec l'acide acétique, il y a formation de calcium acétate hydrate sous forme spongieuse tandis que, avec l'acide phosphatique, la formation de calcium hydrogeno phosphate hydrate est très superficielle. Enfin, avec l'acide chlorhydrique, la surface du mortier est recouverte de chlorure de calcium dihydrate et d'hydroxyde de fer. Les résistances mécaniques sont plus ou moins affectées par la concentration mais aussi et surtout par la nature des acides avec dans l'ordre le plus agressif H{2}SO{4} puis HCl et CH{3}COOH enfin peu de modification pour H{3}PO{4}.

  19. Effect of different degumming processes and some nontraditional neutralizing agent on refining of RBO.

    PubMed

    De, Bijay Krishna; Patel, J D

    2010-01-01

    The present investigation aimed at finding out the effect of different degumming processes and on the use of some nontraditional alkaline material for refining of rice bran oil. Attempt was made to treat crude rice bran oil with H(2)O, and H(3)PO(4) for degumming followed by with alum or H(2)O for dewaxing. After removal of the gums and waxes the oil was neutralized with commonly used NaOH, and some nontraditional neutralizing agents like Na(2)CO(3) and NaHCO(3). Finally the oil was bleached traditionally using earth and charcoal and deodorized. The RBD oil was characterized by determining their color, peroxide value, content of unsaponifiable matter, and free fatty acids. Among the different processes tried degumming with 0.2 %, w/w, H(3)PO(4) followed by dewaxing with 2.0 %, w/w, H(2)O; bleaching with tonsil earth (1.5 %, w/w) and charcoal (0.5 %, w/w) and finally deodorization at 220 degrees C temperature and 2-4 mm Hg pressure resulted best quality oil in terms of the measured parameters. The characteristics of refined rice bran oil could be as content of FFA and UM 0.2 (%, w/w), 2.6 (%, w/w) respectively; color 10.9Y, 2.0R (in 2.54 cm Lovibond Tintometer cell); PV 3.3 (meq/kg). The oil yield is 78-85 % (by weight). PMID:20124753

  20. Characterization and application of expanded graphite modified with phosphoric acid and glucose for the removal of Ni(II) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Jiang, Li; Zhang, Jian; Xu, Xiaoli; Zhang, Jie; Liu, Hai; Guo, Zizhang; Kang, Yan; Li, Yiran; Xu, Jingtao

    2015-12-01

    Three kinds of modified expanded graphite (EG), impregnated with phosphoric acid (H3PO4) (P-EG), impregnated with glucose (G-EG), and impregnated with H3PO4 and glucose (G-P-EG), were prepared under a low temperature (150 °C). The adsorption capacity of G-P-EG (Qm = 7.016 mg/g) is much higher than original expanded graphite (EG Qm = 0.423 mg/g) and other two kinds of modified expanded graphite (P-EG Qm = 0.770 mg/g; G-EG Qm = 0.507 mg/g). The physicochemical properties of EG and G-P-EG were characterized by N2 adsorption/desorption, Boehm's titration and X-ray photoelectron spectroscopy (XPS). EG exhibited higher values of BET surface area (11.357 m2/g) and total pore volume (0.0303 cm3/g) than that of G-P-EG (4.808 m3/g and 0.0109 cm3/g). However, the results of Bohm's titration and XPS showed that G-P-EG contained more surface oxygen-containing functional groups. The Ni(II) adsorption equilibrium data agreed well with the Langmuir model. And the experimental data of EG and G-P-EG fitted better by pseudo-second order model. Based on the results of batch adsorption experiments and XPS analysis, there were several possible mechanisms for Ni(II) adsorption on the G-P-EG, including chemical adsorption, cation exchange, electrostatic attraction and surface complication.

  1. Immobilization of Cu, Pb and Zn in mine-contaminated soils using reactive materials.

    PubMed

    Navarro, Andrés; Cardellach, Esteve; Corbella, Mercé

    2011-02-28

    Immobilization processes were used to chemically stabilize soil contaminated with Cu, Pb and Zn from mine tailings and industrial impoundments. We examined the effectiveness of ordinary Portland cement (OPC), phosphoric acid and MgO at immobilizing Cu, Pb and Zn in soil contaminated by either mine tailings or industrial and mine wastes. The effectiveness was evaluated using column leaching experiments and geochemical modelling, in which we assessed possible mechanisms for metal immobilization using PHREEQC and Medusa numerical codes. Experimental results showed that Cu was mobilized in all the experiments, whereas Pb immobilization with H(3)PO(4) may have been related to the precipitation of chloropyromorphite. Thus, the Pb concentrations of leachates of pure mining and industrial contaminated soils (32-410 μg/l and 430-1000 μg/l, respectively) were reduced to 1-60 and 3-360 μg/l, respectively, in the phosphoric acid experiment. The mobilization of Pb at high alkaline conditions, when Pb(OH)(4)(-) is the most stable species, may be the main obstacle to the use of OPC and MgO in the immobilization of this metal. In the mining- and industry-contaminated soil, Zn was retained by OPC but removed by MgO. The experiments with OPC showed the Zn decrease in the leachates of mining soil from 226-1960 μg/l to 92-121 μg/l. In the industrial contaminated soil, the Zn decrease in the leachates was most elevated, showing >2500 μg/l in the leachates of contaminated soil and 76-173 μg/l in the OPC experiment. Finally, when H(3)PO(4) was added, Zn was mobilized. PMID:21190796

  2. 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

  3. 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...

  4. FURNACE SURBENT 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...

  5. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium hydroxide. 184.1205 Section 184.1205 Food... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration...

  6. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium hydroxide. 184.1205 Section 184.1205 Food... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration...

  7. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium hydroxide. 184.1205 Section 184.1205 Food... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration...

  8. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium hydroxide. 184.1205 Section 184.1205 Food... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration...

  9. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium hydroxide. 184.1205 Section 184.1205 Food... GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration of lime. (b) The...

  10. Anaerobic tissue-dissolving abilities of calcium hydroxide and sodium hypochlorite.

    PubMed

    Yang, S F; Rivera, E M; Baumgardner, K R; Walton, R E; Stanford, C

    1995-12-01

    Closed root canals likely have an oxygen-free environment; most bacteria in canals are anaerobic. These bacteria and other debris are difficult to remove. Unknown is tissue dissolution with chemicals under these anaerobic conditions. This study evaluated and compared dissolving properties of calcium hydroxide (Ca(OH)2) and sodium hypochlorite (NaOCl) on bovine pulp tissue in aerobic and anaerobic environments. Sixty bovine pulp specimens were dried, then randomly divided into six groups. Groups A and B were immersed in Ca(OH)2 + water solution, whereas group C and D were in 2.5% NaOCl. Groups E and F (controls) specimens were placed in distilled water. Groups A, C, and E were incubated anaerobically, and groups B, D, and F were incubated under regular atmospheric conditions, all for 7 days. Percentages of weight loss were compared between groups. Results showed the following: (a) both chemicals partially dissolved pulp tissue, (b) anaerobic environment did not alter tissue-dissolving properties of Ca(OH)2 or NaOCl, and (c) Ca(OH)2 and NaOCl were equal and more effective than water. PMID:8596083

  11. 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 ...

  12. 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...

  13. 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 ...

  14. 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...

  15. 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...

  16. 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...

  17. DEVELOPMENT OF INFRARED METHODS FOR CHARACTERIZATION OF INORGANIC SULFUR SPECIES RELATED TO INJECTION DESULFURIZATION PROCESSES

    EPA Science Inventory

    The report gives results of using photoacoutsic (PA) and diffuse reflectance (DR) detection methods in Fourier transform infrared spectroscopy (FTIRS) to evaluate the reactions of particulate CaO, CaCO3, and Ca(OH)2 samples with S02 at temperatures of 25-900 C. he work involved t...

  18. 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...

  19. 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…

  20. Conditioning of dilute-acid pretreated corn stover hydrolysate liquors by treatment with lime or ammonium hydroxide to improve conversion of sugars to ethanol.

    PubMed

    Jennings, Edward W; Schell, Daniel J

    2011-01-01

    Dilute-acid pretreatment of lignocellulosic biomass enhances the ability of enzymes to hydrolyze cellulose to glucose, but produces many toxic compounds that inhibit fermentation of sugars to ethanol. The objective of this study was to compare the effectiveness of treating hydrolysate liquor with Ca(OH)2 and NH4OH for improving ethanol yields. Corn stover was pretreated in a pilot-scale reactor and then the liquor fraction (hydrolysate) was extracted and treated with various amounts of Ca(OH)2 or NH4OH at several temperatures. Glucose and xylose in the treated liquor were fermented to ethanol using a glucose-xylose fermenting bacteria, Zymomonas mobilis 8b. Sugar losses up to 10% occurred during treatment with Ca(OH)2, but these losses were two to fourfold lower with NH4OH treatment. Ethanol yields for NH4OH-treated hydrolysate were 33% greater than those achieved in Ca(OH)2-treated hydrolysate and pH adjustment to either 6.0 or 8.5 with NH4OH prior to fermentation produced equivalent ethanol yields. PMID:20801647

  1. 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 ...

  2. 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

  3. 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 μm 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

  4. 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...

  5. 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...

  6. 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...

  7. Characteristics and reactivity of rapidly hydrated sorbent for semidry flue gas desulfurization.

    PubMed

    Zhang, Jie; You, Changfu; Zhao, Suwei; Chen, Changhe; Qi, Haiying

    2008-03-01

    Semidry flue gas desulfurization with a rapidly hydrated sorbent was studied in a pilot-scale circulating fluidized bed (CFB) experimental facility. The desulfurization efficiency was measured for various operating parameters, including the sorbent recirculation rate and the water spray method. The experimental results show that the desulfurization efficiencies of the rapidly hydrated sorbent were 1.5-3.0 times higher than a commonly used industrial sorbent for calcium to sulfur molar ratios from 1.2 to 3.0, mainly due to the higher specific surface area and pore volume. The Ca(OH)2 content in the cyclone separator ash was about 2.9% for the rapidly hydrated sorbent and was about 0.1% for the commonly used industrial sorbent, due to the different adhesion between the fine Ca(OH)2 particles and the fly ash particles, and the low cyclone separation efficiency for the fine Ca(OH)2 particles that fell off the sorbent particles. Therefore the actual recirculation rates of the active sorbent with Ca(OH)2 particles were higher for the rapidly hydrated sorbent, which also contributed to the higher desulfurization efficiency. The high fly ash content in the rapidly hydrated sorbent resulted in good operating stability. The desulfurization efficiency with upstream water spray was 10-15% higher than that with downstream water spray. PMID:18441824

  8. 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...

  9. 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...

  10. 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...

  11. 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

  12. 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...

  13. 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

  14. 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 ...

  15. Enhanced biomethane potential from wheat straw by low temperature alkaline calcium hydroxide pre-treatment.

    PubMed

    Reilly, Matthew; Dinsdale, Richard; Guwy, Alan

    2015-08-01

    A factorially designed experiment to examine the effectiveness of Ca(OH)2 pre-treatment, enzyme addition and particle size, on the mesophilic (35 °C) anaerobic digestion of wheat straw was conducted. Experiments used a 48 h pre-treatment with Ca(OH)2 7.4% (w/w), addition of Accellerase®-1500, with four particle sizes of wheat straw (1.25, 2, 3 and 10mm) and three digestion time periods (5, 15 and 30 days). By combining particle size reduction and Ca(OH)2 pre-treatment, the average methane potential was increased by 315% (from 48 NmL-CH4 g-VS(-1) to 202 NmL-CH4 g-VS(-1)) after 5 days of anaerobic digestion compared to the control. Enzyme addition or Ca(OH)2 pre-treatment with 3, 2 and 1.25 mm particle sizes had 30-day batch yields of between 301 and 335 NmL-CH4 g-VS(-1). Alkali pre-treatment of 3mm straw was shown to have the most potential as a cost effective pre-treatment and achieved 290 NmL-CH4 g-VS(-1), after only 15 days of digestion. PMID:25898087

  16. 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.

  17. 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(...

  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. Alkaline solution neutralization capacity of soil.

    PubMed

    Asakura, Hiroshi; Sakanakura, Hirofumi; Matsuto, Toshihiko

    2010-10-01

    Alkaline eluate from municipal solid waste (MSW) incineration residue deposited in landfill alkalizes waste and soil layers. From the viewpoint of accelerating stability and preventing heavy metal elution, pH of the landfill layer (waste and daily cover soil) should be controlled. On the other hand, pH of leachate from existing MSW landfill sites is usually approximately neutral. One of the reasons is that daily cover soil can neutralize alkaline solution containing Ca(2+) as cation. However, in landfill layer where various types of wastes and reactions should be taken into consideration, the ability to neutralize alkaline solutions other than Ca(OH)(2) by soil should be evaluated. In this study, the neutralization capacities of various types of soils were measured using Ca(OH)(2) and NaOH solutions. Each soil used in this study showed approximately the same capacity to neutralize both alkaline solutions of Ca(OH)(2) and NaOH. The cation exchange capacity was less than 30% of the maximum alkali neutralization capacity obtained by the titration test. The mechanism of neutralization by the pH-dependent charge can explain the same neutralization capacities of the soils. Although further investigation on the neutralization capacity of the soils for alkaline substances other than NaOH is required, daily cover soil could serve as a buffer zone for alkaline leachates containing Ca(OH)(2) or other alkaline substances. PMID:20395123

  20. 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